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Terms modified by Nearby Selected AbstractsFlorida Scrub-Jays (Aphelocoma coerulescens) are Sentinels More When Well-Fed (Even with no Kin Nearby)ETHOLOGY, Issue 11 2003Peter A. Bednekoff Sentinels occupy high, exposed positions while other group members forage nearby. If sentinel behavior involves a foraging,predation risk trade-off, animals should be sentinels more when fed supplemental food. When individual Florida scrub-jays (Aphelocoma coerulescens) were fed fragments of peanuts, during the following 30 min they shifted 30% of their time from foraging to sentinel behavior. In a follow-up experiment, we fed either one or two members in each group. As before, the jays reduced their foraging and spent much more time as sentinels when given supplemental food. In each treatment, pairs were sentinels simultaneously considerably less often than expected by chance. The dramatic shift from foraging to sentinel behavior suggests that for Florida scrub-jays sentinel behavior brings substantial benefits for no greater cost than that of lost opportunities to forage. Because the results held for simple mated pairs of scrub-jays, we argue that kin selection and social prestige are not necessary to explain sentinel behavior. [source] Epidemiologic Analysis of Factors Associated with Local Disappearances of Native Ranid Frogs in ArizonaCONSERVATION BIOLOGY, Issue 2 2008CARMEL L. WITTE análisis de factores de riesgo; declinación de anfibios; declinación de ranas; epidemiología de vida silvestre; métodos de control de casos Abstract:,We examined factors that may independently or synergistically contribute to amphibian population declines. We used epidemiologic case,control methodology to sample and analyze a large database developed and maintained by the Arizona Game and Fish Department that describes historical and currently known ranid frog localities in Arizona, U.S.A. Sites with historical documentation of target ranid species (n= 324) were evaluated to identify locations where frogs had disappeared during the study period (case sites) and locations where frog populations persisted (control sites). Between 1986 and 2003, 117 (36%) of the 324 sites became case sites, of which 105 were used in the analyses. An equal number of control sites were sampled to control for the effects of time. Risk factors, or predictor variables, were defined from environmental data summarized during site surveys and geographic information system data layers. We evaluated risk factors with univariate and multifactorial logistic-regression analyses to derive odds ratios (OR). Odds for local population disappearance were significantly related to 4 factors in the multifactorial model. Disappearance of frog populations increased with increasing elevation (OR = 2.7 for every 500 m, p < 0.01). Sites where disappearances occurred were 4.3 times more likely to have other nearby sites that also experienced disappearances (OR = 4.3, p < 0.01), whereas the odds of disappearance were 6.7 times less (OR = 0.15, p < 0.01) when there was a source population nearby. Sites with disappearances were 2.6 times more likely to have introduced crayfish than were control sites (OR = 2.6, p= 0.04). The identification of factors associated with frog disappearances increases understanding of declines occurring in natural populations and aids in conservation efforts to reestablish and protect native ranids by identifying and prioritizing implicated threats. Resumen:,Examinamos los factores que pueden contribuir independiente o sinérgicamente a la declinación de poblaciones de anfibios. Utilizamos una metodología epidemiológica de control de casos para muestrear y analizar una base de datos desarrollada y mantenida por el Departamento de Caza y Pesca de Arizona que describe las localidades históricas y actuales de ranas en Arizona, E. U. A. Los sitios con documentación histórica de las especies de ránidos (n= 324) fueron evaluados para identificar localidades donde las ranas desaparecieron durante el período de estudio (sitios caso) y localidades donde las poblaciones de ranas persistieron (sitios control). Entre 1986 y 2003, 36% (117) de los 324 sitios se volvieron sitios caso, de los cuales 105 fueron utilizados en los análisis. El mismo número de sitios control fueron muestreados para controlar los efectos del tiempo. Los factores de riesgo, o variables predictivas, fueron definidos a partir de datos ambientales obtenidos de los muestreos en los sitios y de capas de datos de un sistema información geográfica. Evaluamos los factores de riesgo con análisis de regresión logística univariada y multivariada para derivar proporciones de probabilidades (PP). Las probabilidad para la desaparición de una población local estuvo relacionada significativamente con 4 factores en el modelo multifactorial. La desaparición de poblaciones de ranas incrementó con la elevación (PP = 2.7 por cada 500 m, p < 0.01). Los sitios donde ocurrieron las desapariciones fueron 4.3 veces más propensos a estar cerca de otros sitios donde ocurrieron desapariciones (PP = 4.3, p < 0.01), mientras que la probabilidad de desaparición fue 6.7 veces menos (PP = 0.15, p < 0.01) cuando había una población fuente cercana. Los sitios con desapariciones fueron 2.6 veces más propensos a tener langostinos introducidos que los sitios control (PP = 2.6, p= 0.04). La identificación de factores asociados con la desaparición de ranas incrementa el conocimiento de las declinaciones de poblaciones naturales y ayuda a los esfuerzos de conservación para el reestablecimiento y la protección de ránidos nativos mediante la identificación y priorización de las amenazas implicadas. [source] FC02.4 Meteorological factors and standard series patch test reactionsCONTACT DERMATITIS, Issue 3 2004Janice Hegewald The existence of seasonal patterns to patch test reactions has been described, but with conflicting causal interpretations. The potential seasonality of patch tests may be due to irritation, changes to skin barrier or changes to immunological functions caused by meteorological fluctuations. For example, increased skin irritability due to cold winter weather and low humidity may cause an increase in irritative/doubtful and weak positive (false positive) reactions. To investigate the extent of the association between weather and patch test results, consecutive patients (N = 73691) patch tested with the standard series of the German Contact Dermatitis Research Group (DKG) at German or Austrian IVDK (http://www.ivdk.de) centres were matched with weather data collected at a nearby (30 km radius) weather station. Temperature and absolute humidity (AH) on the day of patch test application and the two preceding days were averaged to represent the environment most likely to have influenced the skin condition at the time of testing. The results of 24 standard series substances were analyzed with multivariate logistic regression. Half of the standard series substances examined, including fragrance mix, nickel sulphate, and formaldehyde, exhibited evidence of a relationship with meteorological conditions. Fragrance mix and p-Phenylene diamine exhibited the strongest evidence of an association to weather, with the odds of the reactions in all three reaction categories (ir/?, +, ++/+++) increasing during winter conditions. Due to the association between weather and patch test reactivity, the potential effect of meteorological conditions should be considered in the interpretation of patch test reactions. [source] DOES CRIME JUST MOVE AROUND THE CORNER?CRIMINOLOGY, Issue 3 2006A CONTROLLED STUDY OF SPATIAL DISPLACEMENT AND DIFFUSION OF CRIME CONTROL BENEFITS Recent studies point to the potential theoretical and practical benefits of focusing police resources on crime hot spots. However, many scholars have noted that such approaches risk displacing crime or disorder to other places where programs are not in place. Although much attention has been paid to the idea of displacement, methodological problems associated with measuring it have often been overlooked. We try to fill these gaps in measurement and understanding of displacement and the related phenomenon of diffusion of crime control benefits. Our main focus is on immediate spatial displacement or diffusion of crime to areas near the targeted sites of an intervention. Do focused crime prevention efforts at places simply result in a movement of offenders to areas nearby targeted sites,"do they simply move crime around the corner"? Or, conversely, will a crime prevention effort focusing on specific places lead to improvement in areas nearby,what has come to be termed a diffusion of crime control benefits? Our data are drawn from a controlled study of displacement and diffusion in Jersey City, New Jersey. Two sites with substantial street-level crime and disorder were targeted and carefully monitored during an experimental period. Two neighboring areas were selected as "catchment areas" from which to assess immediate spatial displacement or diffusion. Intensive police interventions were applied to each target site but not to the catchment areas. More than 6,000 20-minute social observations were conducted in the target and catchment areas. They were supplemented by interviews and ethnographic field observations. Our findings indicate that, at least for crime markets involving drugs and prostitution, crime does not simply move around the corner. Indeed, this study supports the position that the most likely outcome of such focused crime prevention efforts is a diffusion of crime control benefits to nearby areas. [source] "Let's Go to MY Museum": Inspiring Confident Learners and Museum Explorers at Children's MuseumsCURATOR THE MUSEUM JOURNAL, Issue 1 2007Carol Enseki Recent guests have arrived from as far away as Israel, Ecuador, Japan, and Australia, and as nearby as the Bronx. In the United States, children's museums represent one of the youngest and fastest growing cultural sectors. Our field was founded in 1899 with the opening of the Brooklyn Children's Museum. Anna Billings Gallup, an influential curator and director at the museum from 1902 to 1937, spoke widely about the value of bringing the child into the forefront of museum activities. In the United States, the field grew slowly but steadily to four children's museums in 1925 and to approximately 38 by 1975. In the last three decades, sparked by the groundbreaking work of Michael Spock at the Boston Children's Museum, the field has been energized by an extraordinary boom in new and expanding children's museums. Today there are approximately 350 worldwide. [source] Impact of the invasive alien grass Melinis minutiflora at the savanna-forest ecotone in the Brazilian CerradoDIVERSITY AND DISTRIBUTIONS, Issue 2 2004William A. Hoffmann ABSTRACT Exotic grasses are a serious threat to biodiversity in the cerrado savannas of central Brazil. Of particular concern is the possible role they may have in impeding tree regeneration at gallery (riverine) forest edges and increasing fire intensity, thereby driving gallery forest retreat. Here we quantify the effect of roads and distance from gallery forests on the abundance of the African grass Melinis minutiflora Beauv. and test for an effect of this species on woody plant regeneration and leaf area index. Melinis was present at approximately 70% of the sites near gallery forest edges, with its frequency declining sharply at greater distances from the edge. Melinis frequency was 2.8 times greater where roads were present nearby. Leaf area index (LAI) of the ground layer was 38% higher where Melinis was present than where it was absent. LAI was strongly correlated to fine fuel mass (r2 = 0.80), indicating higher fuel loads where Melinis was present. The abundance of tree and shrub species in the ground layer was negatively related to LAI and to the presence of Melinis. The greater fuel accumulation and reduced tree regeneration caused by Melinis may cause a net reduction in forest area by increasing fire intensity at the gallery forest edge and slowing the rate of forest expansion. [source] Particle clusters in gravel-bed rivers: an experimental morphological approach to bed material transport and stability conceptsEARTH SURFACE PROCESSES AND LANDFORMS, Issue 11 2005Lea Wittenberg Abstract Structured gravel river beds clearly exert a major influence on bed stability. Indexing structural stability by field measurements of bed strength neglects the processes operating to entrain and transport bed material in different parts of each structure. This study takes a morphological approach to interpreting the critical processes, using particle tracing to determine the movement of individual cluster particles over a range of flood event magnitudes and durations. The experiment was carried out on the River South Tyne, UK; it uses flow hydrographs measured nearby and also benefits from previous studies of historical development, channel morphology and sediment transport at the same site. More than 30 clusters were monitored over a seven-month period during which clusters occupied 7,16 per cent of the bed. Threshold flows delimiting three apparently contrasting bed sediment process regimes for cluster particles are tentatively set at 100 m3 s,1 and 183 m3 s,1; durations of flow at these levels are critical for cluster development, rather than flow peak values. Wake particles are transported most easily. Flow straightening in the wandering channel planform reduces the stability of clusters, since mechanical strength is markedly reduced by this change of direction. The overall area covered by clusters between significant transport events varies little, implying a dynamic equilibrium condition. Copyright © 2005 John Wiley & Sons, Ltd. [source] Locomotory and feeding effectors of the tornaria larva of Balanoglossus biminiensisACTA ZOOLOGICA, Issue 2 2001T. C. Lacalli Abstract Lacalli, T. C. and Gilmour, T. H. J. 2001. Locomotory and feeding effectors of the tornaria larva of Balanoglossus biminiensis. ,Acta Zoologica (Stockholm) 82: 117,126 The tornaria ciliary bands and oesophagus were examined ultrastructurally to identify the neural components that control larval behaviour. The circumoral ciliary band is known to be innervated in part by fibres from the apical plate and adoral nerve centres. Within the band itself, however, the only neurones we could find were multipolar cells, an unusual cell type with apical processes that traverse the surface of the band. Similar cells occur in the circumoral bands of echinoderm larvae. The tornaria telotroch has a much larger nerve, but no neurones were found either in the band or nearby, so the source of the fibres in the telotroch nerve remains unknown. In addition to having different innervation, the two bands also respond differently to cholinergic agonists, which elicit telotroch arrests but have no visible effect on the circumoral band. The oesophagus has a well-developed musculature and an extensive nerve plexus. During feeding, the oesophagus repeatedly contracts, forcing excess water out along two lateral channels prior to swallowing. These channels are also sites of gill slit formation, so there is evidently a continuity between the water bypass mechanism of the larva and that of the postmetamorphic juvenile. [source] An attenuation model for distant earthquakesEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 2 2004Adrian Chandler Abstract Large magnitude earthquakes generated at source,site distances exceeding 100km are typified by low-frequency (long-period) seismic waves. Such induced ground shaking can be disproportionately destructive due to its high displacement, and possibly high velocity, shaking characteristics. Distant earthquakes represent a potentially significant safety hazard in certain low and moderate seismic regions where seismic activity is governed by major distant sources as opposed to nearby (regional) background sources. Examples are parts of the Indian sub-continent, Eastern China and Indo-China. The majority of ground motion attenuation relationships currently available for applications in active seismic regions may not be suitable for handling long-distance attenuation, since the significance of distant earthquakes is mainly confined to certain low to moderate seismicity regions. Thus, the effects of distant earthquakes are often not accurately represented by conventional empirical models which were typically developed from curve-fitting earthquake strong-motion data from active seismic regions. Numerous well-known existing attenuation relationships are evaluated in this paper, to highlight their limitations in long-distance applications. In contrast, basic seismological parameters such as the Quality factor (Q -factor) could provide a far more accurate representation for the distant attenuation behaviour of a region, but such information is seldom used by engineers in any direct manner. The aim of this paper is to develop a set of relationships that provide a convenient link between the seismological Q -factor (amongst other factors) and response spectrum attenuation. The use of Q as an input parameter to the proposed model enables valuable local seismological information to be incorporated directly into response spectrum predictions. The application of this new modelling approach is demonstrated by examples based on the Chi-Chi earthquake (Taiwan and South China), Gujarat earthquake (Northwest India), Nisqually earthquake (region surrounding Seattle) and Sumatran-fault earthquake (recorded in Singapore). Field recordings have been obtained from these events for comparison with the proposed model. The accuracy of the stochastic simulations and the regression analysis have been confirmed by comparisons between the model calculations and the actual field observations. It is emphasized that obtaining representative estimates for Q for input into the model is equally important.Thus, this paper forms part of the long-term objective of the authors to develop more effective communications across the engineering and seismological disciplines. Copyright © 2003 John Wiley & Sons, Ltd. [source] How do paedomorphic newts cope with lake drying?ECOGRAPHY, Issue 4 2003Mathieu Denoël Paedomorphosis, in which adult individuals retain larval traits, is widespread in newts and salamanders. Most evolutionary models predict the maintenance of this life-history trait in favourable aquatic habitats surrounded by hostile terrestrial environments. Nevertheless, numerous ponds inhabited by paedomorphic individuals are unpredictable and temporary. In an experimental framework, I showed that paedomorphic newts were able to metamorphose and thus survive in the absence of water. However, the mere decrease of water level or the life space do not seem to induce metamorphosis in paedomorphs. On the contrary, drying up induces almost all individuals to move on land and after that to colonize other aquatic sites located nearby. Such terrestrial migrations allow survival in drying conditions without metamorphosis as long as the distances of terrestrial migration are short. These results are consistent with the presence of paedomorphs in drying ponds and are in favor of classic optimality models predicting metamorphosis in unfavorable environments. [source] Pollinator genetics and pollination: do honey bee colonies selected for pollen-hoarding field better pollinators of cranberry Vaccinium macrocarpon?ECOLOGICAL ENTOMOLOGY, Issue 2 2001James H. Cane Summary 1. Genetic polymorphisms of flowering plants can influence pollinator foraging but it is not known whether heritable foraging polymorphisms of pollinators influence their pollination efficacies. Honey bees Apis mellifera L. visit cranberry flowers for nectar but rarely for pollen when alternative preferred flowers grow nearby. 2. Cranberry flowers visited once by pollen-foraging honey bees received four-fold more stigmatic pollen than flowers visited by mere nectar-foragers (excluding nectar thieves). Manual greenhouse pollinations with fixed numbers of pollen tetrads (0, 2, 4, 8, 16, 32) achieved maximal fruit set with just eight pollen tetrads. Pollen-foraging honey bees yielded a calculated 63% more berries than equal numbers of non-thieving nectar-foragers, even though both classes of forager made stigmatic contact. 3. Colonies headed by queens of a pollen-hoarding genotype fielded significantly more pollen-foraging trips than standard commercial genotypes, as did hives fitted with permanently engaged pollen traps or colonies containing more larvae. Pollen-hoarding colonies together brought back twice as many cranberry pollen loads as control colonies, which was marginally significant despite marked daily variation in the proportion of collected pollen that was cranberry. 4. Caloric supplementation of matched, paired colonies failed to enhance pollen foraging despite the meagre nectar yields of individual cranberry flowers. 5. Heritable behavioural polymorphisms of the honey bee, such as pollen-hoarding, can enhance fruit and seed set by a floral host (e.g. cranberry), but only if more preferred pollen hosts are absent or rare. Otherwise, honey bees' broad polylecty, flight range, and daily idiosyncrasies in floral fidelity will obscure specific pollen-foraging differences at a given floral host, even among paired colonies in a seemingly uniform agricultural setting. [source] Annual movement of adult pike (Esox lucius L.) in a lowland riverECOLOGY OF FRESHWATER FISH, Issue 2 2006A. Koed Abstract,,, The movement of ten radio-tagged adult pikes (57,113 cm) in the River Gudenå, Denmark, was investigated from September 1998 to September 1999. The movements of pike were characterised by long resident periods in the submergent vegetation, interrupted by short excursions to nearby areas. Two periods with more intense movement were observed; one period during early winter; and one period during spring from mid-March to mid-May. The increased movement during early winter may have been initiated by a slight temperature increase at this time, whereas the increased movement during spring coincided with the spawning of pike. Despite suitable spawning areas nearby the areas where pike resided most of the year, several pike, mainly females, migrated to distant localities during spring. [source] Evaluation of eradication measures against Anoplophora chinensis in early stage infestations in EuropeEPPO BULLETIN, Issue 2 2010D. J. Van Der Gaag Eradication efforts are described at 5 sites where infestations of Anoplophora chinensis have been detected in Europe since 2003. The infestations were in France (declared eradicated in 2006), in Croatia, in Italy (Rome) and in the Netherlands (Westland and Boskoop). Each of these infestations was on or nearby a nursery or location where plants originating from Eastern Asia had (probably) been stocked or sold. Infested plants were all found within a distance of 30 m from the presumed source of infestation except in the Rome-infestation where infested plants, in total 40, were found within 500 m of the presumed source of infestation. The history of plant imports and local observations at 3 sites (France, Croatia and Westland in the Netherlands) suggests that larvae arrived in imported plants and adults emerged and laid eggs on plants in the surroundings between 1 and 5 years before the infestation was detected. It was not possible to make such an estimate for the Boskoop infestation in the Netherlands and the Rome infestation in Italy. [source] Florida Scrub-Jays (Aphelocoma coerulescens) are Sentinels More When Well-Fed (Even with no Kin Nearby)ETHOLOGY, Issue 11 2003Peter A. Bednekoff Sentinels occupy high, exposed positions while other group members forage nearby. If sentinel behavior involves a foraging,predation risk trade-off, animals should be sentinels more when fed supplemental food. When individual Florida scrub-jays (Aphelocoma coerulescens) were fed fragments of peanuts, during the following 30 min they shifted 30% of their time from foraging to sentinel behavior. In a follow-up experiment, we fed either one or two members in each group. As before, the jays reduced their foraging and spent much more time as sentinels when given supplemental food. In each treatment, pairs were sentinels simultaneously considerably less often than expected by chance. The dramatic shift from foraging to sentinel behavior suggests that for Florida scrub-jays sentinel behavior brings substantial benefits for no greater cost than that of lost opportunities to forage. Because the results held for simple mated pairs of scrub-jays, we argue that kin selection and social prestige are not necessary to explain sentinel behavior. [source] Patterns of Vocal Interactions in a Bullfrog (Rana catesbeiana) Chorus: Preferential Responding to Far NeighborsETHOLOGY, Issue 8 2000Su L. Boatright-Horowitz In chorusing species, males seem to be spaced non-randomly, and their vocal interactions may be governed by particular behavioral rules. We monitored patterns of vocal interactions in a natural bullfrog (Rana catesbeiana) chorus to determine the probability with which calls of individual frogs would follow each other's in dyadic sequences. Expected probabilities of responses in a dyad were calculated based upon the joint probabilities of calling (relative calling rates) of the individual frogs; observed probabilities of response reflected the actual number of following responses in each dyad. Results of statistical tests comparing observed and expected probabilities of responding revealed that, when dyads were closely spaced, observed probabilities of a following response were significantly less than the expected probabilities. Conversely, when dyads were composed of more distant males, observed probabilities of responding were significantly greater than expected. Observed probabilities of response were correlated with inter-male distances; males called more frequently than expected following calls of far neighbors, and less frequently than expected following calls of near neighbors. These data suggest that males attend to both nearby and distant callers, and adjust the onset of their own vocalizations appropriately. Males may be actively inhibited by calls of their near neighbors, and their calling may be actively elicited by the calls of their far neighbors. [source] Metal-Assisted Hybridization of Oligonucleotides, Evaluation of Circular 2,- O -Me RNA as Ligands for the TAR RNA TargetEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 6 2003Laurence Zapata Abstract Two complementary oligonucleotides were conjugated with terpyridine ligands at their nearby 5,- and 3,-ends. Addition of a stoichiometric amount of a transition metal (Zn2+, Fe2+) resulted in a large increase in the melting temperature of the duplex. The conjugation of TPY to stem-loop oligomers provided an efficient procedure for the cyclisation of the oligomer after the addition of metal ions. Such a short stem-loop oligomer was designed to target the HIV-1 TAR RNA through loop,loop interactions. The addition of Zn2+ ions yielded a good ligand (Kd = 30 nM) for this RNA structural element. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] THE HISTORICAL BIOGEOGRAPHY OF TWO CARIBBEAN BUTTERFLIES (LEPIDOPTERA: HELICONIIDAE) AS INFERRED FROM GENETIC VARIATION AT MULTIPLE LOCIEVOLUTION, Issue 3 2002Neil Davies Abstract Mitochondrial DNA and allozyme variation was examined in populations of two Neotropical butterflies, Heliconius charithonia and Dryas iulia. On the mainland, both species showed evidence of considerable gene flow over huge distances. The island populations, however, revealed significant genetic divergence across some, but not all, ocean passages. Despite the phylogenetic relatedness and broadly similar ecologies of these two butterflies, their intraspecific biogeography clearly differed. Phylogenetic analyses of mitochondrial DNA sequences revealed that populations of D. iulia north of St. Vincent are monophyletic and were probably derived from South America. By contrast, the Jamaican subspecies of H. charithonia rendered West Indian H. charithonia polyphyletic with respect to the mainland populations; thus, H. charithonia seems to have colonized the Greater Antilles on at least two separate occasions from Central America. Colonization velocity does not correlate with subsequent levels of gene flow in either species. Even where range expansion seems to have been instantaneous on a geological timescale, significant allele frequency differences at allozyme loci demonstrate that gene flow is severely curtailed across narrow ocean passages. Stochastic extinction, rapid (re)colonization, but low gene flow probably explain why, in the same species, some islands support genetically distinct and nonexpanding populations, while nearby a single lineage is distributed across several islands. Despite the differences, some common biogeographic patterns were evident between these butterflies and other West Indian taxa; such congruence suggests that intraspecific evolution in the West Indies has been somewhat constrained by earth history events, such as changes in sea level. [source] Effects of fire on surface carbon, energy and water vapour fluxes over campo sujo savanna in central BrazilFUNCTIONAL ECOLOGY, Issue 6 2003A. J. B. Santos Summary 1Tower-based eddy covariance measurements were used to quantify the effect of fire on subsequent carbon dioxide fluxes and water and surface energy balance characteristics for campo sujo savanna located near Brasília in Central Brazil (15°56, S, 47°51, W). Campo sujo is a xeromorphic, open shrub savanna with very scattered but definitely visible shrubs and tree-like shrub elements. We studied two areas, one exposed to a prescribed fire late in the dry season, and a second that had not been burned for the previous 4 years. 2The fire on 22 September 1998 consumed an estimated 26 mol C m,2. Immediately after the fire, evapotranspiration rates decreased and the savanna became a stronger net source of CO2 to the atmosphere. This was attributed to the removal of the still slightly physiologically active grass layer and higher soil CO2 efflux rates as a consequence of elevated surface soil temperatures post-burning. 3On the commencement of the first rains in early October 1998, this situation was reversed, with the burned area rapidly becoming a stronger sink for CO2 and with higher evapotranspiration rates than a nearby unburned (control) area. This difference persisted throughout the wet season (until at least June 1999) and was attributable to greater physiological activity of the regrowing vegetation in the burned area. Early in the growing season, higher soil evaporation rates may also have contributed to faster water use by the previously burned area. 4Overall, we estimate an annual gross primary productivity for the burned area of 135 mol C m,2 year,1, with that for the unburned area being 106 mol C m,2 year,1. Estimated ecosystem respiration rates were more similar on an annual basis (96 and 82 mol C m,2 year,1 for the burned and unburned areas, respectively), giving rise to a substantially higher net ecosystem productivity for the previously burned area (38 vs 24 mol C m,2 year,1). 5Stimulation of photosynthetic activity in the rapid post-fire growth phase means that the negative effects of fire on the ecosystem carbon balance were more or less neutralized after only 12 months. [source] Geoarchaeology of the Boca Negra Wash Area, Albuquerque Basin, New Mexico, USAGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2006Vance T. Holliday Dozens of Paleoindian sites, including the Boca Negra Wash (BNW) Folsom site (LA 124474), are scattered across a basalt plateau (the West Mesa) on the western side of the Albuquerque Basin, and adjacent uplands. The BNW site, like many others in the area, is located near a small (,60 × 90 m) playa basin that formed in a depression on the basalt surface and was subsequently covered by an eolian sand sheet (Unit 1) dated by OSL to ,23,000 yr B.P. Most of the basin fill is ,2 m of playa mud (Units 2 and 3) dating ,13,970 14C yr B.P. (17,160,16,140 cal yr B.P.) at the sand,mud interface to ,2810 14C yr B.P. (,2960,2860 cal yr B.P.) at the top. C/N ratios suggest that the BNW playa basin probably held water more often during the Folsom occupation; stable carbon isotope values indicate C3 vegetation was more common as well, but C4 grasses became dominant in the Holocene. Cores extracted from four playa basins nearby revealed a similar stratigraphy and geochronology, documenting presence of wetlands on playa floors during the Paleoindian occupation of the area. © 2006 Wiley Periodicals, Inc. [source] Tectonics and quaternary evolution of the Northern Apennines watershed area (upper course of Arno and Tiber rivers, Italy)GEOLOGICAL JOURNAL, Issue 1 2009Marco Bonini Abstract This work examines the connection between Quaternary tectonics and erosion/incision processes in the primary Tuscan-Romagna watershed of the Northern Apennines, which essentially coincides with the topographic culmination of the Nero Unit structural ridge. Tectonic and geomorphic information were collected in the area where this ridge is crossed by the upper Tiber River course forming a deep gorge. Structural analysis and field mapping have revealed that the region experienced polyphase tectonics with superposed thrust folding events identifiable both at the map and mesoscopic scales. Hinterland-SSW-verging thrusts and thrust-related folds deformed the whole thrust pile during the latest deformation phase. Backthrusts/backfolds controlled the development of intermountain basins nearby the main watershed during the Early Pleistocene and seemingly deformed, in the Tiber gorge, a low-relief landscape developed in the Early Pleistocene (ca. 1.1,Ma). Successively, the upper Tiber River course area and Apennines axial zone underwent a generalized uplift, which is manifested by the deep incision of palaeo-morphologies. This proposed sequence of events correlates well with the major geodynamic change of the Apennines revealed by an acceleration of uplift rates in the Middle,Late Pleistocene. This latter event may also correlate with increased rates of river incision recorded in Europe as a consequence of uplift and/or climate change. Copyright © 2008 John Wiley & Sons, Ltd. [source] Temporal Elements in the Spatial Extension of Production NetworksGROWTH AND CHANGE, Issue 4 2006JOHAN WOXENIUS ABSTRACT The spatial extension of production networks presents a significant challenge to managers accustomed to reducing lead times by geographically contracting supply chains. This paper extends the theory on time in transportation by defining the elements of transport time, order time, timing, punctuality, and frequency and elaborating on their characteristics. Structured along these elements, it analyses the consequences of extending production networks from within a mature economic region, mainly the EU-15, U.S., and Japan, first to adjacent and then to nearby and finally distant low-cost regions. Distance obviously affects the transport quality in all time dimensions. Except for air parcel services that globally match what road transport offers within an economic region, the longer the distance, the lower the time-related performance. Distant, low-cost regions, meaning China and India, also imply a polarisation between air and sea transport at opposite ends of the time, cost, and capacity scales. This supply gap restricts the types of products traded. The conceptual framework is illustrated in the setting of a global vehicle manufacturer spatially extending its sourcing. It demands that sequenced sub-assemblies and small, cheap, and generic components are delivered from the vicinity of each assembly plant. Batched components can be sourced from adjacent regions, but deliveries from longer distances imply storage at pick-up points to fulfil their time requirements. Hence, the suppliers must offer the manufacturing firm deliveries as if they produce relatively close to the assembly plants. [source] Population trends of Rooks Corvus frugilegus in Spain and the importance of refuse tipsIBIS, Issue 1 2008PEDRO P. OLEA Anthropogenic food from refuse tips can affect population dynamics in birds, especially gulls, but the evidence is mostly circumstantial. We combine analyses of long-term population data and natural experiments to show a positive effect of refuse tips on the growth of the Spanish breeding population of Rooks Corvus frugilegus. In this isolated population of around 2000 breeding pairs, monitored since 1976, birds in colonies less than 10 km from tips fed largely on refuse, particularly during periods of lowest natural food availability. Three lines of evidence support the hypothesis that the supply of refuse influenced breeding numbers, suggesting that this population is limited by food: 1) between 1976 and 2003, the two population nuclei that had access to tips increased 2.1 and 3.7 times more than that without a tip nearby; 2) annual colony growth between 1996 and 2003 was strongly correlated with the availability of tips when other potentially important variables were taken into account; 3) the number of breeding pairs in refuse-foraging colonies declined rapidly after the closure of the local tip and recovered only when a supply of refuse was restored. The effect of tips on colony growth was stronger when the availability of natural foraging habitat around the colonies was low, suggesting that anthropogenic food acts as a buffer against shortage of natural food. Artificial food supplementation may be an effective tool to increase the breeding population of target species, especially those facing a reduction of their foraging habitats. The potential effects on bird species of Directive 1999/31/CE, which is enforcing a massive closure of tips in Europe, are discussed. [source] Habitat selection in a recovering Osprey Pandion haliaetus populationIBIS, Issue 3 2001ASKO LOHMUS Sequential habitat occupation and productivity of Ospreys Pandion haliaetus were studied in the recovering Estonian population from 1985 to 1999. During this period, the number of known nests increased from five to 32. Nest-sites closer to the foraging grounds and with more lakes nearby were occupied first and had the highest productivity. Through a reduction in the quality of sites available, the average productivity of Ospreys decreased as their numbers rose, consistent with despotic distribution models. The sites occupied first during the recolonization were also those that had been the last to be abandoned during the population's decline prior to 1980. However, newcomers preferred sites near established pairs. Therefore, conspecific attraction explained some stochasticity left unexplained by deterministic resource models. [source] A new modification of the immersed-boundary method for simulating flows with complex moving boundariesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 11 2006Jian Deng Abstract In this paper, a new immersed-boundary method for simulating flows over complex immersed, moving boundaries is presented. The flow is computed on a fixed Cartesian mesh and the solid boundaries are allowed to move freely through the mesh. The present method is based on a finite-difference approach on a staggered mesh together with a fractional-step method. It must be noted that the immersed boundary is generally not coincident with the position of the solution variables on the grid, therefore, an appropriate strategy is needed to construct a relationship between the curved boundary and the grid points nearby. Furthermore, a momentum forcing is added on the body boundaries and also inside the body to satisfy the no-slip boundary condition. The immersed boundary is represented by a series of interfacial markers, and the markers are also used as Lagrangian forcing points. A linear interpolation is then used to scale the Lagrangian forcing from the interfacial markers to the corresponding grid points nearby. This treatment of the immersed-boundary is used to simulate several problems, which have been validated with previous experimental results in the open literature, verifying the accuracy of the present method. Copyright © 2006 John Wiley & Sons, Ltd. [source] Distinct expression patterns of the immunogenic differentiation antigen NY-BR-1 in normal breast, testis and their malignant counterpartsINTERNATIONAL JOURNAL OF CANCER, Issue 7 2008Jean-Philippe Theurillat Abstract NY-BR-1 is a differentiation antigen and a potential target for cancer immunotherapy. Its mRNA expression is restricted to breast, testis, prostate and breast cancer by RT-PCR. In this study, we correlated NY-BR-1 protein and mRNA expression on tissue microarrays of mammary, prostatic and testicular malignancies using immunohistochemisty and in situ hybridization with probes for exon 4,7 and 30,33. NY-BR-1 mRNA was confined to primary spermatocytes, suggesting a role in spermatogenesis. Exon 4,7 and 30,33 were equally expressed this cell type. However, NY-BR-1 was absent in all germ cell tumours analyzed (n = 475) and present in one of 56 (2%) prostate carcinomas. In breast, NY-BR-1 mRNA expression was detected in 307 of 442 (70%) primary carcinomas, with strong correlation to its protein expression (p < 0.0001). mRNA expression was significantly stronger and more frequently detected by the exon 30,33 probe than by the exon 4,7 probe (70% vs. 35%, p < 0.0001), indicating the presence of alternative splice variants that lack 5-prime sequences. A similar restricted mRNA pattern was also observed in the normal breast epithelium. NY-BR-1 protein and mRNA correlated significantly with estrogen receptor , (ER,) protein expression (p < 0.0001), with stronger association to NY-BR-1 mRNA than protein (odds ratio 7.7 compared to 4.6). We identified 4 estrogen response elements (ERE)-like sequences nearby the promoter region, suggesting that NY-BR-1 transcription might be controlled by ER,. Accordingly, analysis of matching pairs of primary tumors with their recurrences showed a marked decrease of NY-BR-1 expression in recurrences after tamoxifen treatment (p < 0.0001). © 2007 Wiley-Liss, Inc. [source] A comparative study of the magnitude, frequency and distribution of intense rainfall in the United KingdomINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 12 2010John C. Rodda Abstract During the 1960s, a study was made of the magnitude, frequency and distribution of intense rainfall over the United Kingdom, employing data from more than 120 daily read rain gauges covering the period 1911 to 1960. Using the same methodology, that study was recently updated utilizing data for the period 1961 to 2006 for the same gauges, or from those nearby. This paper describes the techniques applied to ensure consistency of data and statistical modelling. It presents a comparison of patterns of extreme rainfalls for the two periods and discusses the changes that have taken place. Most noticeably, increases up to 20% have occurred in the north-west of the country and in parts of East Anglia. There have also been changes in other areas, including decreases of the same magnitude over central England. The implications of these changes are considered. Copyright © 2009 Royal Meteorological Society [source] Thermal anomaly around the Nojima Fault as detected by fission-track analysis of Ogura 500 m borehole samplesISLAND ARC, Issue 3-4 2001Takahiro Tagami Abstract To better understand heat generation and transfer along earthquake faults, this paper presents preliminary zircon fission-track (FT) length data from the Nojima Fault, Awaji Island, Japan, which was activated during the 1995 Kobe earthquake (Hyogo-ken Nanbu earthquake). Samples were collected of Cretaceous granitic rocks from the Ogura 500 m borehole as well as at outcrops adjacent to the borehole site. The Nojima Fault plane was drilled at a depth of 389.4 m (borehole apparent depth). Fission-track lengths in zircons from localities > 60 m distance from the fault plane, as well as those from outcrops, are characterized by the mean values of ,10,11 ,m and unimodal distributions with positive skewness, which show no signs of an appreciable reduction in FT length. In contrast, those from nearby the fault at depths show significantly reduced mean track lengths of ,6,8 ,m and distributions having a peak around 6,7 ,m with rather negative skewness. In conjunction with other geological constraints, these results are best interpreted by a recent thermal anomaly around the fault, which is attributable to heat transfer via focused fluids from the deep interior of the crust and/or heat dispersion via fluids associated with frictional heating by fault motion. [source] Twenty years of rest returns grazing potential, but not palatable plant diversity, to Karoo rangeland, South AfricaJOURNAL OF APPLIED ECOLOGY, Issue 4 2010Colleen L. Seymour Summary 1.,Up to 73% of the world's rangelands are degraded, and increasing demand for meat in developing countries and a growing human population are likely to exert even greater pressures on rangelands in the next 20,50 years. Restoration of rangeland grazing potential and resilience is therefore important, particularly in the face of climate change. 2.,We investigated the influence of past stocking rates (from 1910 to 1987), rainfall, and current grazing regimes (from 1988 to 2008) on plant assemblages, grazing potential, and diversity of palatable species in southern Karoo rangelands, South Africa. 3.,We used herbivore exclusion experiments to test whether resting rangeland for 20 years enables recovery of plant assemblages (where seed sources are present within 50 m), regardless of previous grazing history. Mean annual rainfall over this period was 15% higher than the mean annual rainfall for the preceding 80 years and included two exceptionally wet years. 4.,While rainfall was a primary driver of total vegetation cover, grazing history explained differences in plant species composition: plots with shared historical grazing intensity were more similar than plots with the same grazing regimes between 1988 and 2008. 5.,In historically heavily-grazed exclusion plots, cover of the palatable species Tripteris sinuata (formerly Osteospermum sinuatum) returned to levels comparable to that in both exclusion and lightly-grazed plots with a moderate grazing history. Five palatable species (Pteronia empetrifolia, Tetragonia spicata, Berkheya spinosa, Hereroa latipetala and Ruschia spinosa) failed to re-establish, however, despite the presence of seed-producing plants nearby. Furthermore, only cover of P. empetrifolia increased significantly in historically moderately-grazed plots. Cover of unpalatable plants (e.g. Pteronia pallens) increased in all plots over time. 6.Synthesis and applications. These findings suggest that present species composition of arid shrublands reflects historical management at time scales greater than 20 years. Despite high rainfall enabling the return of grazing potential through recovery of a single forage species, rest alone did not ensure the return of all palatable species, with implications for rangeland resilience. Restoring the full suite of palatable species over management timeframes will require more complex interventions such as reseeding or selective clearing. [source] Genetic restoration of a stocked brown trout Salmo trutta population using microsatellite DNA analysis of historical and contemporary samplesJOURNAL OF APPLIED ECOLOGY, Issue 4 2006MICHAEL M. HANSEN Summary 1Gene flow from domesticated to wild populations is a major threat to wild salmonid fish. However, few studies have addressed how populations could be restored after admixture has occurred. We analysed the prospects for restoring the previously intensively stocked brown trout population of the Skjern River, Denmark, by identifying remaining non-admixed individuals to be used for supportive breeding. 2We analysed microsatellite DNA markers in historical (1940,50s) and contemporary (1992,2004) samples from the Skjern River system, from the strain of domesticated trout previously used for stocking, and from the neighbouring Storå River. We analysed admixture proportions to estimate the genetic contribution by domesticated trout. We identified non-admixed trout using assignment tests, and further analysed the possible sources of indigenous trout by estimating contemporary migration among populations. 3Genetic differentiation between the historical Storå and Skjern river populations was low (,ST = 0·004), suggesting considerable gene flow in the past. The contemporary Skjern and Storå river populations and a supportive breeding brood stock were strongly admixed, but some non-admixed individuals nevertheless remained in the wild-caught samples. In addition, two resident populations in isolated tributaries were found to be indigenous. The indigenous anadromous individuals from the Skjern River were unlikely to have been recruited from either the isolated tributary populations or the neighbouring Storå River and were presumably derived from unidentified spawning sites in the river system. 4All but one non-admixed anadromous Skjern River trout were females, which we ascribed to sampling bias. Moreover, all non-admixed fish were late-spawning (January,February) whereas the majority of all trout caught for the study were ripe by November,December. The difference in spawning time could be an important factor delaying complete admixture of domesticated and indigenous trout. 5Synthesis and applications. This study demonstrates the feasibility of restoring populations that have been admixed with exogenous individuals, by identifying non-admixed individuals using genetic markers. However, the results also highlight the problem that numbers of identified non-admixed individuals may be small, necessitating identification of nearby, closely related populations that can be incorporated into breeding programmes. [source] Factors affecting predation by buzzards Buteo buteo on released pheasants Phasianus colchicusJOURNAL OF APPLIED ECOLOGY, Issue 4 2001R.E. Kenward Summary 1Information on the effects of wildlife predation on game and livestock is required to allow improved management of all organisms involved. Monitoring of prey, predators and predation mechanisms each suggests important methods, illustrated here by data from common buzzards Buteo buteo and ring-necked pheasants Phasianus colchicus. 2Location data from 136 radio-tagged common buzzards, together with prey remains from 40 nest areas, records from 10 gamekeepers and vegetation surveys, were used to investigate raptor predation at 28 pens from which pheasants were released in southern England. 3Among 20 725 juvenile pheasants released in 1994,95, gamekeepers attributed 4·3% of deaths to buzzards, 0·7% to owls, 0·6% to sparrowhawks, 3·2% to foxes and 0·5% to other mammals. 4Fresh pheasant remains were found on 7% of 91 visits to buzzard nests, and 8% of radio-tagged buzzards had significantly more association than other buzzards with pheasant pens. 5Predation by buzzards was most likely to be recorded at release pens with little shrub cover, deciduous canopies and a large number of released pheasants. The number of pheasants killed was greatest in large pens with extensive ground cover, and the highest proportion of released pheasants was killed in large pens where few were released. However, only 21% of 55 releases had > 2 pheasant kills per week. 6Radio-tagged buzzards were located most often at pheasant-release pens with open, deciduous canopies. Pens were most likely to be visited by buzzards that had fledged nearby, but the proximity of buzzard nests had little influence on how much predation occurred. 7Only a minority of buzzards associated frequently with pheasant pens, and predation was heavy at only a minority of sites, where pen characteristics and release factors probably made it easy for individual buzzards to kill pheasants. We suggest that the occasional heavy losses could be avoided by encouraging shrubs rather than ground cover in pens, by siting pens where there are few perches for buzzards, and perhaps also by high-density releases. 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