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Winter Months (winter + month)
Selected AbstractsThe use of periphytic diatoms as a means of assessing impacts of point source inorganic nutrient pollution in south-eastern AustraliaFRESHWATER BIOLOGY, Issue 5 2006JOCELYN DELA-CRUZ Summary 1. Periphytic diatoms are used as indicators of water quality because their ecological tolerances or preferences to environmental variables are thought to be predictable. However, much of the present autecological information for periphytic diatoms has been derived from studies conducted in the northern hemisphere. In this present study we used periphytic diatoms to determine the impacts of inorganic nutrient pollution in a tidal river system in the temperate latitudes of south-east Australia. In so doing, we assess the suitability of the use of the ,northern hemisphere' ecological tolerance/preference data for periphytic diatoms. 2. Artificial substrates were used to collect periphytic diatoms at 35 sites, which were positioned along the riverbanks and the middle of the river at various distances upstream and downstream of the sewage outfall. The sampling design took into account tidal excursions and the observed sewage plume dynamics. Periphytic diatoms were collected during the austral winter month of August and the austral spring months of September and October. We deployed the artificial substrates for 4 weeks to allow the periphytic diatoms to recruit and colonise, before identifying and enumerating the assemblages. 3. Data analysis included two approaches: multivariate visualisations of combinations of environmental and biological data to investigate shifts in species structure of the periphytic diatom assemblage and multimetric indices based on ecological tolerance/preference data. 4. We found that the spatial patterns inferred from multivariate and multimetric analyses were consistent. Temporal variation in the composition of the periphytic diatom assemblage was greater than the spatial variation along horizontal sections of the river (in any one deployment) due mainly to shifts between winter and spring species. 5. Outfall effects were most apparent in winter, possibly because subsequent deployments were swamped by growth of spring periphytic diatoms. The outfall effects included a shift towards pollutant tolerant species and a reduction in the variability of the periphytic diatom assemblage across the river. 6. We conclude that the use of periphytic diatoms and associated ecological tolerance/preference data as a means of assessing impacts of point source inorganic nutrient pollution is effective. An understanding of river and sewage flow patterns is essential to the design of appropriate monitoring programmes and to the interpretation of results, especially as periphytic diatoms are sensitive to many environmental variables. [source] Biological Sustainability of Live Shearing of Vicuña in PeruCONSERVATION BIOLOGY, Issue 1 2007CATHERINE TERESA SAHLEY Andes; conservación basada en comunidades; Vicugna vicugna Abstract:,The vicuña's (Vicugna vicugna) fiber is highly valued as an export product that is made into luxury fabric and clothing. The price of fiber in 2004 was $566/kg, which makes the fiber a potentially important source of income for Andean agropastoral communities and serves as an incentive to allow vicuña grazing on high-elevation Andean landscapes. It is presumed that a shorn vicuña has little value for poachers, so shearing vicuñas could serve as a disincentive to poaching. Thus, the supply of vicuña fiber may be sustainable if it is procured through live shearing, which should serve as a powerful conservation tool. We evaluated the effects of capture and shearing on the demography of vicuña in one site located in the Salinas Aguada Blanca Reserve, Arequipa, Peru, where vicuñas were captured and shorn in spring and then returned to the wild. We conducted fixed-width line-transect censuses from 1997 to 2003 of this population. We compared the proportion of young born to females that were shorn versus females that were unshorn for the 3 years in which shearing occurred. We evaluated the effect of capture and shearing on proportion of young born to shorn and unshorn females at a second site, Picotani, Puno. The wild population in Arequipa that underwent capture and shearing showed a steady increase in total population and average density between 1997 and 2003. No significant difference was found between the proportion of young per female for shorn and unshorn females at either site. We conclude that in spring, capture and live shearing of vicuñas can be biologically sustainable. Further research is needed to determine whether shearing during winter months is biologically sustainable. Resumen:,La fibra de vicuña (Vicugna vicugna) tiene gran valor como un producto de exportación que es transformado en tela y ropa de lujo. El precio de la fibra en 2004 era de $566/kg, lo que hace que la fibra sea una fuente de ingreso potencialmente importante para comunidades agropastoriles Andinas y servir como un incentivo para permitir el pastoreo de vicuñas en paisajes Andinos elevados. Se presume que una vicuña trasquilada tiene poco valor para cazadores furtivos, por lo que el trasquilado de vicuñas pudiera servir como un desincentivo para la caza furtiva. Por lo tanto, el abastecimiento de fibra de vicuña puede ser sustentable si se obtiene del trasquilado de animales vivos, y el trasquilado de animales vivos debería ser una poderosa herramienta de conservación. Evaluamos los efectos de la captura y trasquilado sobre la demografía de vicuñas en un sitio localizado en la Reserva Salinas Aguada Blanca, Arequipa, Perú, donde las vicuñas fueron capturadas y trasquiladas en primavera y liberadas. Realizamos censos de esta población en transectos lineales de ancho fijo de 1997 a 2003. Comparamos la proporción de crías de hembras trasquiladas con las de hembras no trasquiladas durante los 3 años en que ocurrió el trasquilado. Evaluamos el efecto de la captura y trasquilado sobre la proporción de crías de hembras trasquiladas y no trasquiladas en un segundo sitio, Picotani, Puno. La población silvestre en Arequipa que fue capturada y trasquilada mostró un incremento constante en la población total y la densidad promedio entre 1997 y 2003. No se encontró diferencia significativa entre la proporción de crías por hembra para hembras trasquiladas y no trasquiladas en ningún sitio. Concluimos que en la primavera, la captura y trasquilado de vicuñas vivas puede ser biológicamente sostenible. Se requiere más investigación para determinar si el trasquilado durante el invierno es biológicamente sostenible. [source] Characteristics and dynamics of multiple intertidal bars, north Lincolnshire, EnglandEARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2006Selma van Houwelingen Abstract Multiple intertidal bars and troughs, often referred to as ,ridges and runnels', are significant features on many macrotidal sandy beaches. Along the coastline of England and Wales, they are particularly prevalent in the vicinity of estuaries, where the nearshore gradient is gentle and a large surplus of sediment is generally present. This paper examines the dynamics of such bar systems along the north Lincolnshire coast. A digital elevation model of the intertidal morphology obtained using LIDAR demonstrates that three to five intertidal bars are consistently present with a spacing of approximately 100 m. The largest and most pronounced bars (height = 0·5,0·8 m) are found around mean sea level, whereas the least developed bars (height = 0·2,0·5 m) occur in the lower intertidal zone. Annual aerial photographs of the intertidal bar morphology were inspected to try to track individual bars from year to year to derive bar migration rates; however, there is little resemblance between concurrent photographs, and ,resetting' of the intertidal profile occurs on an annual basis. Three-dimensional beach surveys were conducted monthly at three locations along the north Lincolnshire coast over a one-year period. The intertidal bar morphology responds strongly to the seasonal variation in the forcing conditions, and bars are least numerous and flattest during the more energetic winter months. Morphological changes over the monthly time scale are strongly affected by longshore sediment transport processes and the intertidal bar morphology can migrate along the beach at rates of up to 30 m per month. The behaviour of intertidal bars is complex and varies over a range of spatial and temporal scales in response to a combination of forcing factors (e.g. incident wave energy, different types of wave processes, longshore and cross-shore sediment transport), relaxation time and morphodynamic feedback. Copyright © 2005 John Wiley & Sons, Ltd. [source] Comparison of the life history strategies of three Dysdercus true bugs (Heteroptera: Pyrrhocoridae), with special reference to their seasonal host plant useENTOMOLOGICAL SCIENCE, Issue 4 2005Katsuyuki KOHNO Abstract The life history strategy and seasonal host plant use of three Dysdercus bugs (D. cingulatus, D. poecilus and D. decussatus) were compared based on 2 years of twice monthly observations on Ishigaki-jima Island (24°N, 124°E) in the southernmost part of Japan. Dysdercus poecilus reproduced almost year round, exclusively on Sida rhombifolia, which bears fruit and/or seeds almost year round. Dysdercus cingulatus reproduced successively on various malvaceous and bombacaceous plant species, according to their seasonal fruiting cycles. Its robust reproduction was observed on Hibiscus makinoi during winter months and on Chorisia speciosa and Bombax ceiba in early summer, whereas small-scale reproduction was observed on various malvaceous plant species during the summer and autumn months. Dysdercus decussatus reproduced on Hibiscus tiliaceus and Thespesia populnea during the summer months, when these host plants bear abundant fruit and/or seeds, and its adults formed conspicuous aggregations without copulation on the underside of the leaves of those plants from November to the subsequent May. Each Dysdercus species showed a species-specific life history strategy according to the differences in the phenology of their host plants. [source] Dynamics of the SAR11 bacterioplankton lineage in relation to environmental conditions in the oligotrophic North Pacific subtropical gyreENVIRONMENTAL MICROBIOLOGY, Issue 9 2009Alexander Eiler Summary A quantitative PCR assay for the SAR11 clade of marine Alphaproteobacteria was applied to nucleic acids extracted from monthly depth profiles sampled over a 3-year period (2004,2007) at the open-ocean Station ALOHA (A Long-term Oligotrophic Habitat Assessment; 22°45,N, 158°00,W) in the oligotrophic North Pacific Ocean. This analysis revealed a high contribution (averaging 36% of 16S rRNA gene copies) of SAR11 to the total detected 16S rRNA gene copies over depths ranging from the surface layer to 4000 m, and revealed consistent spatial and temporal variation in the relative abundance of SAR11 16S rRNA gene copies. On average, a higher proportion of SAR11 rRNA gene copies were detected in the photic zone (< 175 m depth; mean = 38%) compared with aphotic (> 175 m depth; mean = 30%), and in the winter months compared with the summer (mean = 44% versus 33%, integrated over 175 m depth). Partial least square to latent structure projections identified environmental variables that correlate with variation in the absolute abundance of SAR11, and provided tools for developing a predictive model to explain time and depth-dependent variations in SAR11. Moreover, this information was used to hindcast temporal dynamics of the SAR11 clade between 1997 and 2006 using the existing HOT data set, which suggested that interannual variations in upper ocean SAR11 abundances were related to ocean-climate variability such as the El Niño Southern Oscillation. [source] Sex Differences in Feeding Activity Results in Sexual Segregation of Feral GoatsETHOLOGY, Issue 5 2008Robin I. M. Dunbar Sexual segregation is common in ungulates. We show, in a high latitude population of feral goats where behavioural synchrony and fission rates have been shown to be the best explanation for segregation, that it is differences explicitly in the feeding time requirements of the two sexes (but not those for other activities) that best explains the variations in monthly frequencies of segregation. However, this effect is less marked during winter months when short day length forces the time budgets of the two sexes to converge. We argue that the various explanations for segregation can best be interpreted as separate factors in a multivariate model in which species- and habitat-specific weightings influence the relative importance of these variables, and thus the likelihood that segregation will occur. [source] Variation in abundance of Norwegian spring-spawning herring (Clupea harengus, Clupeidae) throughout the 20th century and the influence of climatic fluctuationsFISH AND FISHERIES, Issue 3 2000R. Toresen A long-term (1907,98) virtual population analysis (VPA) was made for Norwegian spring-spawning herring (NSSH), which is a huge pelagic fish stock in the north-east Atlantic. It shows that this herring stock has had large fluctuations during the last century; these fluctuations have mainly been determined by variations in the temperature of the inflowing water masses to the region. The spawning stock biomass (SSB) increased from a rather low level in the early years of this century and reached a high level of around 14 million tons by 1930. The spawning stock biomass then decreased to a level of around 10 million tons by 1940, but increased again to a record high level of 16 million tons by 1945. The stock then started to decrease and during the next 20-year period fell to a level of less than 50 000 tons by the late 1960s. Through the 1970s and 1980s, the stock slowly recovered and after the recruitment of strong year classes in 1983 and 1990,1992 the stock recovered to a spawning stock biomass of about 10 million tons. The long-term fluctuation in spawning stock biomass is caused by variations in the survival of recruits. It is found that the long-term changes in spawning stock abundance are highly correlated with the long-term variations in the mean annual temperature of the inflowing Atlantic water masses (through the Kola section) into the north-east Atlantic region. The recruitment is positively correlated with the average temperature in the Kola section in the winter months, January,April, which indicates that environmental factors govern the large-scale fluctuations in production for this herring stock. [source] Spatial correlation patterns in coastal environmental variables and survival rates of salmon in the north-east Pacific OceanFISHERIES OCEANOGRAPHY, Issue 4 2002Franz J. Mueter We examined spatial correlations for three coastal variables [upwelling index, sea surface temperature (SST), and sea surface salinity (SSS)] that might affect juvenile salmon (Oncorhynchus spp.) during their early marine life. Observed correlation patterns in environmental variables were compared with those in survival rates of pink (O. gorbuscha), chum (O. keta), and sockeye (O. nerka) salmon stocks to help identify appropriate variables to include in models of salmon productivity. Both the upwelling index and coastal SST were characterized by strong positive correlations at short distances, which declined slowly with distance in the winter months, but much more rapidly in the summer. The SSS had much weaker and more variable correlations at all distances throughout the year. The distance at which stations were no longer correlated (spatial decorrelation scale) was largest for the upwelling index (> 1000 km), intermediate for SST (400,800 km in summer), and shortest for SSS (< 400 km). Survival rate indices of salmon showed moderate positive correlations among adjacent stocks that decreased to zero at larger distances. Spatial decorrelation scales ranged from approximately 500 km for sockeye salmon to approximately 1000 km for chum salmon. We conclude that variability in the coastal marine environment during summer, as well as variability in salmon survival rates, are dominated by regional scale variability of several hundred to 1000 km. The correlation scale for SST in the summer most closely matched the observed correlation scales for survival rates of salmon, suggesting that regional-scale variations in coastal SST can help explain the observed regional-scale covariation in survival rates among salmon stocks. [source] Root recovery rates for Phytophthora cinnamomi and rate of symptom development from root rot on Abies fraseri trees over 7 yearsFOREST PATHOLOGY, Issue 1 2009G. J. Griffin Summary Phytophthora root rot on Abies fraseri trees was monitored from 2001 to 2007 within the disease front of a 12-year-old Virginia plantation where trees had been dying of the disease since 1994. After a slow increase in early foliage symptom development from July 2001 to September 2002, the frequency of A. fraseri trees with early symptoms accelerated for about 15 months. While the slow increase occurred during a 18.7% lower than normal rainfall period and the acceleration occurred during a 31.2% higher than normal rainfall period, the percentage of trees with early symptoms continued to increase during the mid-winter months (December,February) when the estimated mean minimum daily soil temperature (25 cm depth) was unfavourable (<10°C) to Phytophthora cinnamomi pathogenic activity. The time required for trees to progress from early foliage symptoms to completely dead foliage, from November 2000 to October 2007, was highly variable, ranging from 4 to 35 months. Root recovery rates for P. cinnamomi, assayed on a selective medium, were 6.4 times greater for symptomatic foliage trees than for asymptomatic foliage trees in this deep, silt-loam soil. Following an atypical cold period in February 2007, when the mean minimum daily soil temperature was 0.8°C, symptomatic roots yielded only a low level of germinable propagules of P. cinnamomi. Further, during an atypical midsummer in 2007 (June,August), when the soil water potential was at or below ,9 bars for 68 of 92 days, symptomatic roots yielded no germinable propagules of P. cinnamomi. Addition of thiophanate-methyl to the selective medium aided P. cinnamomi isolation by inhibiting many undesired pythiaceous colonies growing from symptomatic roots. [source] Endochitinase activity in the apoplastic fluid of Phellinus weirii -infected Douglas-fir and its association with over wintering and antifreeze activityFOREST PATHOLOGY, Issue 5 2003A. Zamani Summary Extracellular proteins were extracted from Phellinus weirii infected Douglas-fir (Pseudotsuga menziesii var. menziesii) roots and needles to examine endochitinase activity. Chitinases have been associated with the plant's defence response against fungal attack because they hydrolyse chitin, a structural component of fungal cell walls. Protein separation using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Western immunoblot analysis using a polyclonal antibody specific to an endochitinase-like protein (ECP) resulted in the detection of up to three polypeptides between 27 and 30 kDa in size. Two-dimensional gel electrophoresis (2-D PAGE) followed by Western immunoblot analysis revealed that the apoplastic fluid contained multiple ECP isoforms with isoelectric points (pIs) ranging from 5.3 to 5.8 and molecular masses of 27,30 kDa. Chitinase activity in needle and root tissues was measured spectrophotometrically using a colorimetric assay. A gel overlay technique using glycol chitin as a substrate for endochitinase was applied to confirm that the ECP antibody detected an enzymatically active protein. The apoplastic fluid collected from P. weirii -infected winter Douglas-fir needles showed anti-freeze activity and seasonal analysis of needle tissue showed some evidence of ECP accumulation in winter months. ECP was distributed systemically throughout the tree. Increased levels of endochitinase activity in the region of P. weirii infection supports a physiological role for ECP in the plant defence response. Résumé Les protéines extra-cellulaires ont été extraites des racines et aiguilles de douglas (Pseudotsuga menziesii var menziesii) infectés par Phellinus weirii (Murr.) Gilbn., pour étudier l'activité endochitinase. Les chitinases ont été associées aux réactions de défense des plantes contre les attaques fongiques parce-qu'elles hydrolysent la chitine, un composant de la paroi des cellules fongiques. La séparation des protéines, réalisée par électrophorèse en gel de polyacrylamide avec sodium dodecyl sulfate (SDS-PAGE), suivie par une analyse par Western immunoblot en utilisant un anticorps polyclonal spécifique d'une protéine de type endochitinase (ECP), a permis la détection de 3 polypeptides de taille comprise entre 27 et 30 kDa. Une électrophorèse sur gel en 2-dimensions (2-D PAGE) suivie par une analyse par Western immunoblot a révélé que le fluide apoplastique contient de multiples isoformes d'ECP avec des pI dans une gamme de 5.3 à 5.8 et des masses moléculaires de 27 à 30 kDa. L'activité chitinase dans les aiguilles et tissus racinaires a été mesurée par spectrophotométrie par une méthode colorimétrique. Une technique d'overlay utilisant de la chitine glycol comme substrat de l'endochitinase a été appliquée pour confirmer que l'anticorps ECP avait détecté une protéine active du point de vue enzymatique. Le fluide apoplastique d'aiguilles récoltées en hiver sur des douglas infectés par P. weirii a montré une activité antigel et l'analyse saisonnière des tissus foliaires a montré une certaine accumulation d'ECP pendant l'hiver. L'ECP est répartie de façon systémique dans l'ensemble de l'arbre. Les niveaux accrus d'activité endochitinase dans la zone infectée par P. weirii suggère un rôle physiologique de l'ECP dans les réactions de défense de la plante. Zusammenfassung Aus Wurzeln und Nadeln von mit Phellinus weirii infizierten Douglasien (Pseudotsuga menziesii var. menziesii) wurden extrazelluläre Proteine extrahiert, um die Endochitinase-Aktivität zu bestimmen. Chitinasen werden mit der pflanzlichen Abwehrreaktion auf Pilzinfektionen in Verbindung gebracht, da sie Chitin, eine Strukturkomponente der pilzlichen Zellwand, hydrolysieren. Die Proteine wurden mit Natrium-Dodecyl-Sulfat-Polyacrylamid-Gelelektrophorese (SDS-PAGE) getrennt, gefolgt von einer Western Immunoblot-Analyse mit einem gegen ein Endochitinase-ähnliches Protein (ECP) spezifischen polyklonalen Antikörper. Hiermit liessen sich bis zu drei Polypeptide zwischen 27-30 kDa nachweisen. Eine zweidimensionale Gelelektrophorese (2-D PAGE) mit anschliessender Western Immunoblot-Analyse ergab, dass die Apoplastenflüssigkeit multiple ECP-Isoformen enthielt (mit pIs von 5,3 bis 5,8 und Molekularmassen von 27 bis 30 kDa). Die Chitinase-Aktivität wurde auch im Nadel- und Wurzelgewebe spektrophotometrisch mit einer Farbreaktion gemessen. Um sicher zu stellen, dass der ECP-Antikörper ein enzymatisch aktives Protein nachwies, wurde eine Gel-Overlay-Methode verwendet, mit Glycolchitin als Substrat für die Endochitinase. Die Apoplastenflüssigkeit der Nadeln von mit P. weirii infizierten Douglasien zeigte in Winterzustand eine Antifrost-Aktivität, ihre Analyse während des gesamten Jahres ergab aber keine Hinweise auf eine ECP-Anreicherung während der Wintermonate. ECP war systemisch im gesamten Baum enthalten. Die erhöhte Endochitinase-Aktivität in Bereichen mit P. weirii -Infektion lässt auf eine physiologische Rolle von ECP in der Pflanzenabwehr schliessen. [source] The effects of groundwater level and vegetation on creep of the Mam Tor landslipGEOLOGY TODAY, Issue 4 2010Sam Green The creeping Mam Tor landslide (North Derbyshire, UK) is sliding slowly downhill at up to 0.5 m per year. Annual measurements using conventional surveying techniques have shown that creep is exacerbated by periods of heavy rainfall, but to establish a detailed correlation between creep and groundwater levels requires spatially and temporally higher resolution monitoring. We have acquired three years of such data from wire creep meters, borehole piezometers and rainfall monitoring. These measurements showed that creep is strongly focused into the winter months and that it correlates well with groundwater levels. Summer grass and fern growth exerts a strong influence on rainfall infiltration, recycling much of the summer rainfall back to the atmosphere, and explaining the seasonal variability of creep motion. [source] The causes and consequences of maxillofacial injuries in elderly peopleGERODONTOLOGY, Issue 1 2002K. Rehman Abstract Objective: The occurrence of trauma in older people is well-documented; however the incidence of maxillofacial trauma is scarcely reported. Therefore, the objective of this study is to determine the causes and consequences of maxillofacial trauma in older people. Design: A five-year (March 95 - March 2000) retrospective study was earned out of all patients over the age of 65 years with facial trauma presenting to Accident and Emergency Department (A&E). The information was collected using the medical notes and discharge summaries. Setting: The Departments of A&E and Maxillofacial Surgery. Subjects: A total of 42 patients' records were examined for study related data. Results: A total of 42 patients were seen during the study period. Thirty-six gave a history of a fall, of which 15 had tripped, 5 had slipped, 3 resulted from a Transient Ischaemic Attack (TIA), 1 as a result of alcohol abuse, in 1 a prosthetic knee gave way and 11 gave no cause for the fall. Of the remaining 6 patients. 5 were assaulted and 1 had a wardrobe fall on top of him. The majority of the falls occurred during the winter months. Maxillofacial injuries were noted in 27 of the 42 patients. Sixteen patients had cheekbone fractures, 8 mandibular fractures, 2 midface and 1 orbital complex fracture. Twenty-five percent of cheekbone fractures and 50% of mandibular fractures were treated surgically. Medical history was noted in 27 patients. Conclusions: This study clearly demonstrates the majority of the facial trauma in the older people can be treated conservatively unless the patients complain of functional problems. [source] Global climate patterns explain range-wide synchronicity in survival of a migratory seabirdGLOBAL CHANGE BIOLOGY, Issue 1 2009STEPHANIE JENOUVRIER Abstract To predict the impact of climate change over the whole species distribution range, comparison of adult survival variations over large spatial scale is of primary concern for long-lived species populations that are particularly susceptible to decline if adult survival is reduced. In this study, we estimated and compared adult survival rates between 1989 and 1997 of six populations of Cory's shearwater (Calonectris diomedea) spread across 4600 km using capture,recapture models. We showed that mean annual adult survival rates are different among populations along a longitudinal gradient and between sexes. Variation in adult survival is synchronized among populations, with three distinct groups: (1) both females and males of Corsica, Tremiti, and Selvagem (annual survival range 0.88,0.96); (2) both females and males of Frioul and females from Crete (0.82,0.92); and (3) both females and males of Malta and males from Crete (0.74,0.88). The total variation accounted for by the common pattern of variation is on average 71%, suggesting strong environmental forcing. At least 61% of the variation in survival is explained by the Southern Oscillation Index fluctuations. We suggested that Atlantic hurricanes and storms during La Niña years may increase adult mortality for Cory's shearwater during winter months. For long-lived seabird species, variation in adult survival is buffered against environmental variability, although extreme climate conditions such as storms significantly affect adult survival. The effect of climate at large spatial scales on adult survival during the nonbreeding period may lead to synchronization of variation in adult survival over the species' range and has large effects on the meta-population trends. One can thus worry about the future of such long-lived seabirds species under the predictions of higher frequency of extreme large-scale climatic events. [source] Elevated metabolic costs while resting on water in a surface feeder: the Black-legged Kittiwake Rissa tridactylaIBIS, Issue 1 2007ELIZABETH M. HUMPHREYS Measurements of the energy costs of individual behaviours provide insights into how animals trade-off resource allocation and energy acquisition decisions. The energetic costs while resting on water are poorly known for seabirds but could comprise a substantial proportion of their daily energy expenditure. We measured the cost of resting on water in Black-legged Kittiwakes Rissa tridactyla, a species which does not fly during the night and for which estimating energy expenditure while resting on the water is therefore important. Their resting metabolic rate on water at 12.5 °C was at least 40% higher compared with resting at the same temperature in air. This indicates that, at comparable temperatures, metabolic costs are elevated for birds resting at sea compared with on land. We argue that Kittiwakes meet much of this extra thermoregulatory demand by dedicated metabolic activity. During the winter months, their costs are likely to be even higher owing to lower sea temperatures. Accordingly, we suggest that migration to milder latitudes, following breeding, will provide enhanced benefits, particularly to seabirds such as Kittiwakes which rest on the sea surface during darkness. [source] Sex, diet and feeding method-related differences in body condition in the Oystercatcher Haematopus ostralegusIBIS, Issue 1 2001SARAH E.A. Measurements were made of Oystercatcher corpses to find the most reliable measure of body condition in live birds. Total body weight was as accurate as muscle thickness in assessing the weight of the pectoral muscles, a major store of protein reserves. Total body weight was also a good indicator of fat reserves. Wing-length was the most reliable measure of body size. Body condition in live birds was measured as an individual's residual weight derived from a general linear model of (loge) body weight against age, month, (loge) wing-length and time since capture. On the Exe estuary in autumn, there was no significant difference in body condition between same-age Oystercatchers of different diets and feeding methods. In the winter months, however, body condition differed significantly between mussel feeders using different feeding methods, and between mussel feeders and birds that fed on worms and clams. Differences between diet/feeding methods were not the same for each age group. Birds with the highest mean body condition index in adults were mussel hammerers, in immatures mussel stabbers and in juveniles, worm/clam feeders. No significant difference in body condition was found between the sexes in any age group in autumn. In winter, when birds with the same diet/feeding method were considered, females were significantly heavier than males. However, when birds of all diets and feeding methods were combined, weight differences between the sexes were not apparent. We examine reasons why birds with certain diets and feeding methods may be heavier than others in winter, and why females are sometimes heavier than males. We conclude that, in most cases, it is due to differences between birds in their ability to achieve a common target weight. However, we conclude that adult females try to achieve a higher target weight than males, probably as a premigratory and prebreeding strategy. In the light of this, we consider the consequences for adult females, in terms of reproductive success and survival, of specializing in diets and feeding methods associated with lower body weights in winter. [source] Variability and trends in the directional wave climate of the Southern HemisphereINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 4 2010Mark A. Hemer Abstract The effect of interannual climate variability and change on the historic, directional wave climate of the Southern Hemisphere is presented. Owing to a lack of in situ wave observations, wave climate in the Southern Hemisphere is determined from satellite altimetry and global ocean wave models. Altimeter data span the period 1985 to present, with the exception of a 2-year gap in 1989,1991. Interannual variability and trends in the significant wave height are determined from the satellite altimeter record (1991 to present), and the dominant modes of variability are identified using an empirical orthogonal function (EOF) analysis. Significant wave heights in the Southern Ocean are observed to show a strong positive correlation with the Southern Annular Mode (SAM), particularly during Austral autumn and winter months. Correlation between altimeter derived significant wave heights and the Southern Oscillation Index is observed in the Pacific basin, which is consistent with several previous studies. Variability and trends of the directional wave climate are determined using the ERA-40 Waves Re-analysis for the period 1980,2001. Significant wave height, mean wave period and mean wave direction data are used to describe the climate of the wave energy flux vector. An EOF analysis of the wave energy flux vector is carried out to determine the dominant modes of variability of the directional seasonal wave energy flux climate. The dominant mode of variability during autumn and winter months is strongly correlated to the SAM. There is an anti-clockwise rotation of wave direction with the southward intensification of the Southern Ocean storm belt associated with the SAM. Clockwise rotation of flux vectors is observed in the Western Pacific Ocean during El-Nino events. Directional variability of the wave energy flux in the Western Pacific Ocean has previously been shown to be of importance to sand transport along the south-eastern Australian margin, and the New Zealand region. The directional variability of the wave energy flux of the Southern Ocean associated with the SAM is expected to be of importance to the wave-driven currents responsible for the transport of sand along coastal margins in the Southern Hemisphere, in particular those on the Southern and Western coastal margins of the Australian continent. Copyright © 2009 Royal Meteorological Society [source] Intra-seasonal variability of wintertime temperature over East AsiaINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2004Dao-Yi Gong Abstract There has been a profound warming over East Asia during the winter months (November through to March) over the past few decades. The goal of this study is to address the question of whether the daily temperature has become more variable in conjunction with this warming by using observed temperature data obtained from 155 Chinese and Korean stations. Prior to the analysis, the annual cycle is removed to obtain daily temperature anomalies for each winter for each station. Results show that the intra-seasonal variance generally decreases, implying that the daily temperatures are becoming less variable. Considering all stations as a whole, the rate of change is ,0.49°C2 per decade (equivalent to ,3.59% per decade). The changes are more robust in the northeastern portion of China. In contrast, there are no dominant trends for the skewness coefficients, except for clear negatively skewed trends in northeastern China. These results are consistent with an increase in the number of extremely cold events. Over the region, the frequency of low-temperature extremes (as low as below minus two standard deviations) increases at a rate of change of 0.26 days per decade, significant at the 95% confidence level. Both the Siberian high and Arctic oscillation (AO) exert a notable influence on the temperature variance. Intra-seasonal variance of the Siberian high and AO are significantly correlated with the temperature variance, whereas the seasonal mean state of the AO affects the temperature variance by modulating the high-frequency components of the Siberian high. The intra-seasonal variance of the Siberian high tends to decline at a rate of change of ,10.7% per decade, significant at the 99% level; meanwhile, the mean wintertime AOs have strengthened in the last few decades. These two climate features together make a considerable contribution to the changes in intra-seasonal temperature variance in East Asia. Copyright © 2004 Royal Meteorological Society [source] A 10 year cloud climatology over Scandinavia derived from NOAA Advanced Very High Resolution Radiometer imageryINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 9 2003Karl-Göran Karlsson Abstract Results from a satellite-based method to compile regional cloud climatologies covering the Scandinavian region are presented. Systematic processing of multispectral image data from the NOAA Advanced Very High Resolution Radiometer (AVHRR) instrument has been utilized to provide monthly cloud climatologies covering the period 1991,2000. Considerable local-scale variation of cloud amounts was found in the region. The inland Baltic Sea and adjacent land areas exhibited a large-amplitude annual cycle in cloudiness (high cloud amounts in winter, low cloud amounts in summer) whereas a weak-amplitude reversed annual cycle (high cloud amounts with a weak maximum in summer) was found for the Scandinavian mountain range. As a contrast, conditions over the Norwegian Sea showed high and almost unchanged cloud amounts during the course of the year. Some interesting exceptions to these patterns were also seen locally. The quality of the satellite-derived cloud climatology was examined through comparisons with climatologies derived from surface cloud observations, from the International Satellite Cloud Climatology Project (ISCCP) and from the European Centre for Medium-range Weather Forecasts ERA-40 data set. In general, cloud amount deviations from surface observations were smaller than 10% except for some individual winter months, when the separability between clouds and snow-covered cold land surfaces is often poor. The ISCCP data set showed a weaker annual cycle in cloudiness, generally caused by higher summer-time cloud amounts in the region. Very good agreement was found with the ERA-40 data set, especially for the summer season. However, ERA-40 showed higher cloud amounts than SCANDIA and ISCCP during the winter season. The derived cloud climatology is affected by errors due to temporal AVHRR sensor degradation, but they appear to be small for this particular study. The data set is proposed as a valuable data set for validation of cloud description in numerical weather prediction and regional climate simulation models. Copyright © 2003 Royal Meteorological Society [source] Links between circulation and changes in the characteristics of Iberian rainfallINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 13 2002C. M. Goodess Abstract Investigation of the links between atmospheric circulation patterns and rainfall is important for the understanding of climatic variability and for the development of empirical circulation-based downscaling methods. Here, spatial and temporal variations in circulation-rainfall relationships over the Iberian Peninsula during the period 1958,97 are explored using an automated circulation classification scheme and daily rainfall totals for 18 stations. Links between the circulation classification scheme and the North Atlantic oscillation (NAO) are also considered, as are the direct links between rainfall and the NAO. Trends in rainfall and circulation-type frequency are explored. A general tendency towards decreasing mean seasonal rainfall over the peninsula, with the exception of the southeastern Mediterranean coast, hides larger changes in wet day amount and rainfall probability. There is a tendency towards more, less-intensive rain days across much of Iberia, with a tendency towards more, more-intensive rain days along the southeastern Mediterranean coast, both of which are reflected in changes in rainfall amount quantiles. A preliminary analysis indicates that these changes may have occurred systematically across all circulation types. Comparison of the trends in rainfall and in circulation-type frequency suggests possible links. These links are supported by linear regression analyses using circulation-type frequencies as predictor variables and rainfall totals for winter months as the predictands. The selected predictor variables reflect the main circulation features influencing winter rainfall across the peninsula, i.e. the strong influence of Atlantic westerly and southwesterly airmasses over much of the peninsula, of northerly and northwesterly surface flow over northern/northwestern Spain and northern Portugal and the stronger effect of Mediterranean rather than Atlantic influences in southeastern Spain. The observed rainfall changes cannot, however, be explained by changes in circulation alone. Copyright © 2002 Royal Meteorological Society. [source] Spatial and temporal 850 hPa air temperature and sea-surface temperature covariances in the Mediterranean region and their connection to atmospheric circulationINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 6 2002C. J. Lolis Abstract The spatial and temporal covariability between the lower troposphere and sea surface temperatures (SSTs) are studied in the Mediterranean basin for the period 1958,98. Monthly air temperature anomalies for the 850 hPa pressure level (T-850hPa) at 2.5° × 2.5° grid points and SST anomalies in 5° × 5° grid boxes are utilized. As a first step, factor analysis is applied on both sets of data in order to reduce their dimensionality. Then, canonical correlation analysis is applied and this leads to one statistically significant pair of canonical variates for winter and to two pairs for summer. In winter, a teleconnection (see-saw) between western Europe and the eastern Mediterranean at the 850 hPa level is revealed, and a corresponding weaker one between the areas of central-west and eastern Mediterranean for SST. The correlation between T-850hPa and SST appears higher over the eastern Mediterranean. In summer, the first pair of canonical variates reveals a covariability between T-850hPa and SST in the western Mediterranean, and the second one shows a covariability in the eastern Mediterranean, without the existence of any strong spatial teleconnection. The analysis is repeated, using time lags of 1 month, or longer, in order to detect any possible non-synchronous relation. Statistically significant results are found only when T-850hPa leads SST with a time lag of 1 month. In particular, the results are statistically significant for winter only, and the findings are similar to those of the first analysis. Therefore, the existence of a 1 month time scale SST persistence is detected for winter months. Copyright © 2002 Royal Meteorological Society. [source] Influence of environmental stress on skin tone, color and melanogenesis in Japanese skinINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2005K. Kikuchi Introduction It is needless to say that one of the most potent environmental stress for melanogenesis of the human skin is the effect of ultraviolet (UV) light from the sunlight. Characteristic skin aging as a result of this UV light is recognized as photoaging. Clinical features in photoaging are wrinkles, skin laxity, coarseness, leathery, yellowing, lentigenes, mottled pigmentation, telangiectasia, sebaceous hypertrophy and purpura. There is an apparent difference in clinical features in photoaging among different races, i.e. between Caucasians, African American and Asians that include Japanese. Not only photo skin type but also environmental factors, such as climate, latitude, altitude and their habit of sunbathing, smoking and skin care influence the characteristic development of their photoaging. Racial difference in photoaging Caucasians tend to develop skin laxity and fine wrinkles more than Asians [1]. Asians tend to produce coarser wrinkles than the Caucasians although their development is rather late in life. There is also a difference in the skin color. Pigmentation is an earliest and prominent skin changes in Asians [1] and it increases with age [2]. In contrast, pigmentation is not apparent in the Caucasians although redness probably because of an increase in cutaneous vascularization becomes prominent in middle aged Caucasians [2]. Chung reported that seborrheic keratosis is a major pigmentary lesion in men, whereas hyperpigmented macules are prominent features in women in Koreans [3]. Melanogenesis pigmentation disorders in Japanese Ephelides (freckles) are commonly found in those with photo skin type I who have fair skin and red eyes and blond hair. They are also found in the Japanese. Clinical feature reveals that multiple small pigmentary macules on sun-exposed areas mainly on the mid-portion of the face. These lesions seem to be familial, becoming apparent even in early childhood after sun exposure. Melasma is an acquired pigmentary disorder commonly found in middle aged Japanese women characterized by irregular brown macules and patches on the sun-exposed areas on the face typically as bilaterally present macules on the cheeks. An increase in sex hormones as a result of pregnancy and intake of contraceptive pills is one of the etiological factors to develop melasma. Sun exposure also worsens it. Nevus of Ota is also a common pigmentary disorder found in the Japanese. It is usually unilateral, blue-brown to slate-gray pigmentary macules on the eyelid and cheek that appear in early childhood or in puberty. Acquired dermal melanocytosis is also a pigmentary disorder, in which dermal melanocytes are found as shown in nevus of Ota, characterized by bilateral brown to blue-gray macules on the forehead, temple, eyelid and malar areas in middle aged Japanese women. This tends to be misdiagnosed as melasma. Solar lentigo is an acquired pigmented macule induced by sun exposure. Solar lentigines are usually multiple, circumscribed brown macules. There are two types of solar lentigo. One is a small macular type, characterized by multiple, small brown macules whose diameter is less than 5 mm, being similar to ephelides (freckles). The other type is a large macular type, characterized by a few round to oval, brown macules whose diameter is beyond 1 cm. Some of their surface are hyperkeratotic and become elevated to produce seborrheic keratosis. Again, the early sign of photoaging in Japanese is pigmentated spots and these pigmentation disorders increase with age. Among the pigmentary changes, nevus of Ota, acquired dermal melanocytosis, melasma and large macular type of solar lentigo are characteristic skin changes found in the Japanese in addition to ephelides and small macular type of solar lentigo. Seasonal changes of the various functional properties of the skin including skin color assessed by non-invasive bioengineering techniques [4]. When we consider skin tone, color and melanogenesis, UV light from the sunlight is the most potent environmental stress, although we cannot forget also the important influence of environmental relative humidity affects our skin functions as well as its appearance. We investigated seasonal influences on the various properties of the skin in 39 healthy Japanese females consisting of different age groups. Their skin is thought to be affected by the UV light in summer, and by the exposure to the dry and cold air in winter. Materials and methods Biophysical, non-invasive measurements, including transepidermal water loss (TEWL) as a parameter for the barrier function of the stratum corneum (SC), high frequency conductance as a parameter for the hydration state of the SC, skin color and casual surface lipid levels, were conducted during late summer and winter months. Skin color was determined with a chromameter according to the L*a*b* CIE 1976 system, where L* is an attribute on the luminance scale, a* that on the red versus green scale and b* that on the yellow versus blue scale. All the measurements were conducted in an environment controlled-chamber (21 ± 1 °C room temperature, and 50 ± 3% relative humidity). Results The barrier function of the SC was found to be significantly impaired in winter on the cheek as compared with that measured in summer, whereas no such seasonal change was apparent both in the hydration state of the SC and sebum levels on the cheek. In the assessment of the skin color on the cheek, a significant increase in a* (redness) and a decrease in b* (yellowness) were observed in winter. In contrast, on the flexor forearm, the values of L* (luminescence) increased in winter, but no seasonal change was noted in the values of a* and b*. In this study, skin changes with aging were also found by the non-invasive bioengineering methods. The value of TEWL on the cheek tended to increase with age, whereas no significant change was observed in the value of TEWL on the forearm. In the assessment of skin color, b* value on the cheek significantly increased with age whereas a* and L* values on the cheek did not show any significant change with age. Summary of this study We think that such an increase in yellowness with aging of the cheek skin is a phenomenon unique to the Japanese (Asians) since an increase in b* value was not observed in Caucasians [2]. The facial skin that is always exposed shows barrier impairment in a dry and cold winter environment and demonstrates increased yellowness in skin color because of a prolonged exposure to the UV light from the sun in the summer season. The non-invasive bioengineering methods are useful to demonstrate even invisible seasonal changes occurring in the same individuals and changes with age occurring in the skin. References 1.,Goh, S.H. The treatment of visible signs of senescence: the Asian experience. Br. J. Dermatol.122, 105,109 (1990). 2.,LeFur, I., Numagami, K., Guinot, C. et al. Age-related reference values of skin color in Caucasian and Japanese healthy women according to skin site. Pigment Cell Res. 7, 67 (1999). 3.,Chung, J.H., Lee, S.H., Youn, C.S. et al. Cutaneous photodamage in Koreans: influence of sex, sun exposure, smoking, and skin color. Arch. Dermatol. 137, 1043,1051 (2001). 4.,Kikuchi, K., Kobayashi, H., Le Fur, I. et al. Winter season affects more severely the facial skin than the forearm skin: comparative biophysical studies conducted in the same Japanese females in later summer and winter. Exog. Dermatol. 1, 32,38 (2002). [source] Temperate and tropical algal-sea anemone symbiosesINVERTEBRATE BIOLOGY, Issue 2 2001Gisèle Muller-Parker Abstract. In this review, we seek to develop new insights about the nature of algal-sea anemone symbioses by comparing such associations in temperate and tropical seas. Temperate seas undergo pronounced seasonal cycles in irradiance, temperature, and nutrients, while high irradiance, high temperature, and low nutrients are seasonally far less variable in tropical seas. We compare the nature of symbiosis between sea anemones (= actinians) and zooxanthellae (Symbiodinium spp.) in both regions to test tropical paradigms against temperate examples and to identify directions for future research. Although fewer anemone species are symbiotic in temperate regions, they are locally dominant and ecologically important members of the benthic community compared to the tropics. Zooxanthella densities tend to be lower in temperate anemones, but data are limited to a few species in both temperate and tropical seas. Zooxanthella densities are far more stable over time in temperate anemones than in tropical anemones, suggesting that temperate symbioses are more resistant to fluctuations in environmental parameters such as irradiance and temperature. Light-saturated photosynthetic rates of temperate and tropical zooxanthellae are similar, but temperate anemone hosts receive severely reduced carbon supplies from zooxanthellae during winter months when light is reduced. Symbiont transmission modes and specificity do not show any trends among anemones in tropical vs. temperate seas. Our review indicates the need for the following: (1) Investigations of other temperate and tropical symbiotic anemone species to assess the generality of trends seen in a few "model' anemones. (2) Attention to the field ecology of temperate and tropical algal-anemone symbioses, for example, how symbioses function under seasonally variable environmental factors and how zooxanthellae persist at high densities in darkness and winter. The greater stability of zooxanthella populations in temperate hosts may be useful to understanding tropical symbioses in which bleaching (loss of zooxanthellae) is of major concern. (3) Study of the evolutionary history of symbiosis in both temperate and tropical seas. Continued exploration of the phylogenetic relationships between host anemones and zooxanthella strains may show how and why zooxanthellae differ in anemone hosts in both environments. [source] Relationships between tail-flicking, morphology, and body condition in MoorhensJOURNAL OF FIELD ORNITHOLOGY, Issue 1 2006Fernando Alvarez ABSTRACT Prey-predator communication of alertness has been reported for Moorhens (Gallinula chloropus) and other species of birds. Because ability to flee is probably related to body condition, healthy potential prey may behave more conspicuously to send predators an unambiguous message. Moorhens have a contrasting rump patch that is flashed by rapid tail-flicking. During two winter months, we observed sex-related differences in the rate of tail-flicking. Females tail-flicked at a faster rate than males, and more vigilant and more symmetrical males tail-flicked faster. The rate of tail-flicking was negatively correlated to the heterophil/lymphocyte ratio in both sexes and positively correlated to hematocrit and albumin/globulin ratio in females. These results suggest that male and female Moorhens in better physical condition tail-flick at a faster rate and support the pursuit deterrent hypothesis, with healthy individuals appearing to inform predators that they would be difficult to capture. SINOPSIS Es conocida la comunicación del estado de alerta de las presas hacia los predadores potenciales en la Gallineta Gallinula chloropus y en otras especies de aves. Puesto que la facilidad de captura está probablemente relacionada con la condición física, sería de esperar que los individuos presa en mejor condición física actuaran de forma más conspicua, pudiendo así informar sin ambigüedad a los predadores. La Gallineta presenta un escudo anal contrastado, que se hace más conspicuo mediante rápidos movimientos verticales de la cola. Durante dos meses invernales se registraron las diferencias en la tasa de movimiento de cola con relación al sexo de los sujetos, así como su relación con la tasa de vigilancia y con varios parámetros de condición física. Las hembras presentaron mayor tasa de exhibición del escudo anal que los machos, y los más vigilantes y más simétricos de éstos realizaron una exhibición más rápida. Mientras que en ambos sexos la tasa de exhibición apareció relacionada negativamente con la razón heterófilos/linfocitos, en las hembras se mostró positivamente relacionada con su hematocrito y con la razón albúmina/globulina. Estos resultados sugieren que los machos y hembras con mejor salud, así como los machos con tarsos más simétricos, realizan una más rápida exhibición, lo que apoya la hipótesis del efecto disuasorio a la persecución, ya que las presas potenciales podrían estar informando a los predadores respecto a la dificultad de su captura. [source] Seasonal foraging movements and migratory patterns of female Lamna ditropis tagged in Prince William Sound, AlaskaJOURNAL OF FISH BIOLOGY, Issue 2 2005L. B. Hulbert Conventional and electronic tags were used to investigate social segregation, distribution, movements and migrations of salmon sharks Lamna ditropis in Prince William Sound, Alaska. Sixteen salmon sharks were tagged with satellite transmitters and 246 with conventional tags following capture, and were then released in Prince William Sound during summer 1999 to 2001. Most salmon sharks sexed during the study were female (95%), suggesting a high degree of sexual segregation in the region. Salmon sharks congregated at adult Pacific salmon Oncorhynchus spp. migration routes and in bays near Pacific salmon spawning grounds in Prince William Sound during July and August. Adult Pacific salmon were the principal prey in 51 salmon shark stomachs collected during summer months in Prince William Sound, but the fish appeared to be opportunistic predators and consumed sablefish Anoplopoma fimbria, gadids, Pacific herring Clupea pallasi, rockfish Sebastes spp. and squid (Teuthoidea) even when adult Pacific salmon were locally abundant. As Pacific salmon migrations declined in late summer, the salmon sharks dispersed; some continued to forage in Prince William Sound and the Gulf of Alaska into autumn and winter months, while others rapidly moved south-east thousands of kilometres toward the west coasts of Canada and the U.S. Three movement modes are proposed to explain the movement patterns observed in the Gulf of Alaska and eastern North Pacific Ocean: ,focal foraging' movements, ,foraging dispersals' and ,direct migrations'. Patterns of salmon shark movement are possibly explained by spatio-temporal changes in prey quality and density, an energetic trade-off between prey availability and water temperature, intra-specific competition for food and reproductive success. Transmissions from the electronic tags also provided data on depth and water temperatures experienced by the salmon sharks. The fish ranged from the surface to a depth of 668 m, encountered water temperatures from 4·0 to 16·8° C and generally spent the most time above 40 m depth and between 6 and 14° C (60 and 73%, respectively). [source] Respiratory syncytial virus and human rhinoviruses are the major causes of severe lower respiratory tract infections in KuwaitJOURNAL OF MEDICAL VIROLOGY, Issue 8 2010M. Khadadah Abstract Respiratory infections are very common in Kuwait, yet little is known about the cause of severe lower respiratory tract infections. This study was designed to investigate the viral cause of lower respiratory tract infections using sensitive molecular methods. PCR was applied to investigate 10 respiratory viruses in respiratory samples from 1,014 patients aged between 3 days to 76 years with acute lower respiratory tract infections. Of the 1,014 patients with lower respiratory tract infections, 288 (28.4%) had a viral infection. One hundred fifty-five (53.8%) presented with bronchiolitis, 100 (43.7%) with pneumonia, and 33 (11.5%) with croup. One hundred six (36.8%) and 99 (34.4%) patients had evidence of respiratory syncytial virus and human rhinoviruses infections, respectively. Adenoviruses were detected in 44 (15.2%) patients, while influenza A virus in 21 (7.3%) patients. The majority of respiratory syncytial virus infections (84%) were among patients aged <1 year. Similarly, of the 99 patients infected by human rhinoviruses, 50 (50.5%) were also among this age group. In contrast, most of influenza A virus infections, 12 of 21 (57.1%), were among patients aged over 16 years. Parainfluenza virus-2 and human coronaviruses were not detected in any of the patients' samples. Over the 3-year period, most of the hospitalized patients were seen during the autumn and winter months from October through March. These data show that respiratory syncytial virus and human rhinoviruses may be the major causes of lower respiratory tract infections in children admitted to hospital in Kuwait. J. Med. Virol. 82:1462,1467, 2010. © 2010 Wiley-Liss, Inc. [source] 30,Seasonal control of phytoplankton biomass and productivity in coastal british columbia lakes and reservoirsJOURNAL OF PHYCOLOGY, Issue 2003J. M. Davies Factors controlling algal abundance and carbon fixation form a cornerstone of aquatic ecology. Central among these are light, nutrients, and grazers. We measured 14C fixation over one year in six coastal BC lakes that differed in trophic status and grazer community structure. The lakes in our study were never covered with ice, so mixing due to wind energy was more similar to summer months and light levels were higher during winter than comparable ice-covered lakes. Our study, therefore, offered a unique opportunity to examine how seasonal changes in light and temperature affects the functioning of these lakes. While many of our study lakes had higher chlorophyll concentrations during winter months, only the lake with a community dominated by small grazers maintained moderate nutrient deficiency throughout the year and increased 14C-fixation during the winter (Jan,Feb). [source] Temperature functions of the rate coefficients of net N mineralization in sandy arable soils.JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 4 2004Part II. Abstract The aim of this study was to evaluate experimentally derived temperature functions for the rate coefficients of net N mineralization in sandy arable soils from NW Germany via field measurements. In part I of this paper (Heumann and Böttcher, 2004), different temperature functions for the rate coefficients of a two-pool first-order kinetic equation were derived by long-term laboratory incubations at 3°C to 35°C. In this paper, field net N mineralization during winter of 25 plots was measured in undisturbed soil columns with a diameter of 20,cm to the depth of the Ap horizon. Mean simulated net N mineralization with the most adequate multiple functions corresponded also best with the mean of the measured values despite of an overestimation of about 10%. Distinctly larger deviations under use of other temperature functions (Arrhenius, Q10) were directly related to their deviations from mean, experimentally derived rate coefficients. Simulated net N mineralization in the soil columns was significantly correlated with measured values, regardless of the temperature functions. Yet the goodness of fit was generally relatively low due to the spatial variability of measured net N mineralization within replicate soil columns, although the mean CV (38%) was by far not extraordinary. The pool of slowly mineralizable N contributed considerably to net N mineralization during four to five winter months, on an average 10.0 kg N ha,1, about one third of total simulated N mineralization. Sometimes, it contributed even 21.3 kg N ha,1, which is almost sufficient to reach the EU drinking-water limit for nitrate in these soils. Simulations with widely used functions that were once derived from loess soils overestimated mineralization from pool Nslow in the studied sandy arable soils by a factor of two. Die Temperaturfunktionen der Reaktionskoeffizienten der N-Nettomineralisation in sandigen Ackerböde nII. Überprüfung anhand von Mineralisationsmessungen im Freiland Ziel dieser Untersuchung war die Überprüfung experimentell ermittelter Temperaturfunktionen für die Reaktionskoeffizienten der N-Nettomineralisation in sandigen Ackerböden NW-Deutschlands anhand von Freilandmessungen. In Teil I der Arbeit (Heumann and Böttcher, 2004) wurden verschiedene Temperaturfunktionen für die Reaktionskoeffizienten zweier N-Pools mit Reaktionskinetik erster Ordnung mittels Langzeit-Laborinkubationen bei 3 bis 35°C bestimmt. In diesem Artikel wurde von 25 Plots die winterliche N-Nettomineralisation im Freiland in ungestörten Bodensäulen mit einem Durchmesser von 20,cm bis zur Tiefe des Ap-Horizontes gemessen. Im Mittel gaben die Simulationen mit den am besten passenden, multiplen Funktionen die Messergebnisse auch am besten wieder, trotz einer Überschätzung um etwa 10%. Deutlich größere Abweichungen bei Benutzung anderer Temperaturfunktionen (Arrhenius, Q10) standen in direkter Beziehung zu deren Abweichungen von den mittleren, experimentell ermittelten Reaktionskoeffizienten. Die simulierte N-Nettomineralisation war unabhängig von den Temperaturfunktionen signifikant mit den Messergebnissen korreliert. Jedoch war die Güte der Anpassung im Allgemeinen relativ niedrig aufgrund der räumlichen Variabilität der gemessenen N-Nettomineralisation innerhalb der einzelnen Säulen eines Plots, obwohl der mittlere CV (38%) bei weitem nicht außergewöhnlich war. Der langsam mineralisierbare N-Pool trug beträchtlich zur N-Nettomineralisation innerhalb von vier bis fünf Wintermonaten bei, durchschnittlich 10,0 kg N ha,1, etwa ein Drittel der gesamten simulierten N-Mineralisation. In manchen Böden waren es sogar 21,3 kg N ha,1, was fast ausreicht, um den EU-Trinkwassergrenzwert für Nitrat in diesen Böden zu erreichen. Simulationen mit häufig benutzten Funktionen, die ursprünglich an Lössböden ermittelt wurden, überschätzten die Mineralisation aus dem Pool Nslow in den untersuchten Sandböden um den Faktor zwei. [source] COMPARISON OF PROCESS-BASED AND ARTIFICIAL NEURAL NETWORK APPROACHES FOR STREAMFLOW MODELING IN AN AGRICULTURAL WATERSHED,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 3 2006Puneet Srivastava ABSTRACT: The performance of the Soil and Water Assessment Tool (SWAT) and artificial neural network (ANN) models in simulating hydrologic response was assessed in an agricultural watershed in southeastern Pennsylvania. All of the performance evaluation measures including Nash-Sutcliffe coefficient of efficiency (E) and coefficient of determination (R2) suggest that the ANN monthly predictions were closer to the observed flows than the monthly predictions from the SWAT model. More specifically, monthly streamflow E and R2 were 0.54 and 0.57, respectively, for the SWAT model calibration period, and 0.71 and 0.75, respectively, for the ANN model training period. For the validation period, these values were ,0.17 and 0.34 for the SWAT and 0.43 and 0.45 for the ANN model. SWAT model performance was affected by snowmelt events during winter months and by the model's inability to adequately simulate base flows. Even though this and other studies using ANN models suggest that these models provide a viable alternative approach for hydrologic and water quality modeling, ANN models in their current form are not spatially distributed watershed modeling systems. However, considering the promising performance of the simple ANN model, this study suggests that the ANN approach warrants further development to explicitly address the spatial distribution of hydrologic/water quality processes within watersheds. [source] Factors affecting the duration of activity by pine martens (Martes martes) in the Bia,owie,a National Park, PolandJOURNAL OF ZOOLOGY, Issue 4 2000Andrzej Zalewski Abstract The duration of activity bouts by pine martens Martes martes was studied in the pristine deciduous forests in Bia,owie,a National Park (north-eastern Poland). From 1991 to 1996, 14 martens were monitored by radio-tracking throughout 5823 h. On average, male martens were active for 9 h/day and females for 8.5 h/day. The duration of the martens' diel activity varied greatly among bimonthly periods (from 2.8 h/day in February,March to 12 h/day in June,July). Martens decreased their activity from 13 h/day on warm days to 2.5 h/day on cooler days. In the winter months, when martens curtailed their activity, they often hunted larger prey or scavenged ungulate carcasses. On average, 69% of the martens' active time was during the night. The number of activity bouts per day varied from one to six (mean 2.6) and increased with growing ambient temperature. Activity bouts of males were significantly longer (4 h, on average) than those of females (3 h) and were not related to ambient temperature. The duration of short inactive bouts increased in the cold season and inactivity lasted longer in females than in males. [source] Demographic Characteristics of Lytechinus variegatus (Echinoidea: Echinodermata) from Three Habitats in a North Florida Bay, Gulf of MexicoMARINE ECOLOGY, Issue 1 2000Steven D. Beddingfield Abstract. The population densities, spatial distributions, size frequencies, growth rates, longevity and reproductive activities of sub-populations of the sea urchin Lytechinus variegatus were investigated over a two-year period. Sea urchins were examined in three habitats in Saint Joseph Bay, Florida, which is within the northern limits of their distribution. Densities of sea urchins, which ranged as high as 35 individuals ·,2, fluctuated seasonally at all sites and were higher in seagrass beds comprised of Thalassia testudinum than Syringodium filiforme or on a sand flat. A cold front caused large-scale, catastrophic mortality among adult, and especially juvenile, sea urchins in nearshore habitats of the Bay in the spring of 1993, leading to a dramatic decline in sea urchin densities at the Thalassia seagrass site. The population recovered over 6 months at this site and was attributable to immigration of new adults. Juvenile recruitment displayed both interannual and site-specific variability, with recruitment being highest in seagrass habitats in fall and spring. The most pronounced recruitment event occurred in fall 1993 at the Thalassia site. Spatial distributions of adult individuals ascertained monthly never varied from random in the seagrass beds (T. testudinum and S. filiforme) or during spring, summer or fall months on the sand flat. Nonetheless, aggregations of adult sea urchins were observed on the sand flat in the winter months and were associated with patchy distributions of plant food resources. Juvenile sea urchins (< 25 mm test diameter) exhibited aggregations at all sites and 67 % of all juveniles under 10 mm test diameter (91 of 165 individuals observed) were found under the spine canopies of adults. Measurements of the inducibility of spawning indicated peak gametic maturity in all three sub-populations in spring and summer. Gonad indices varied between habitats and years, but distinct maxima were detected, particularly in spring 1993 and late summer 1994. The mean gonad index of individuals at the Syringodium seagrass site was 2- to 4-fold higher than the other sites in spring 1993 and gonad indices were much higher at all sites in spring of 1993 than 1994. Estimates of growth based on changes in size frequency cohorts coupled with measurements of growth bands on lantern demipyramids indicated that L. variegatus in three habitats of Saint Joseph Bay have similar growth rates and attain a mean test diameter of approximately 35 mm in one year. In contrast to populations within the central biogeographical range of the species, which may attain test diameters up to 90 mm, the largest individuals recorded in Saint Joseph Bay were 60 mm in test diameter, and almost all individuals were no more than 45 mm in test diameter or two years of age. The demographics of L. variegatus in the northern limits of their distribution appear to be strongly influenced by latitudinally driven, low-temperature events and secondarily by local abiotic factors, especially springtime low salinities, which may negatively impact larval development and recruitment. [source] | |||||||||||||||||||||||||||||||