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Selected AbstractsTesting the assumptions of chronosequences in successionECOLOGY LETTERS, Issue 5 2008Edward A. Johnson Abstract Many introductory ecology textbooks illustrate succession, at least in part, by using certain classic studies (e.g. sand dunes, ponds/bogs, glacial till, and old fields) that substituted space for time (chronosequence) in determining the sequences of the succession. Despite past criticisms of this method, there is continued, often uncritical, use of chronosequences in current research on topics besides succession, including temporal changes in biodiversity, productivity, nutrient cycling, etc. To show the problem with chronosequence-based studies in general, we review evidence from studies that used non-chronosequence methods (such as long-term study of permanent plots, palynology, and stand reconstruction) to test the space-for-time substitution in four classic succession studies. In several cases, the tests have used the same locations and, in one case, the same plots as those in the original studies. We show that empirical evidence invalidates the chronosequence-based sequences inferred in these classic studies. [source] Residency and movement of stream-dwelling Japanese charr, Salvelinus leucomaenis, in a central Japanese mountain streamECOLOGY OF FRESHWATER FISH, Issue 3 2002T. Nakamura Abstract,,,The residency and movement of stream-dwelling adult (2+ and older) Japanese charr, Salvelinus leucomaenis, were studied by mark and recapture experiments in the Jadani Stream, a headwater tributary of the Tedori River, central Japan, from 1986 to 1989. Of the marked fish, 31.3,58.3% were recaptured in the same pools where they had been caught during the study periods of summer (June,August), autumn (August,November) and winter,spring (November to the next June) and no seasonal movement was observed. The mean distances that the fish moved during the study periods ranged from 139.0 to 502.3 m and many movements longer than 1000 m were observed. Between the resident and the moved fish, there was little difference in body length, growth rate or sex. For the fish that had been resident in the same pools and riffles at previous recaptures, most fish were recaptures in the same locations at the next recapture. Conversely, for the fish that moved previously, most fish were recaptured in different locations from previous sites at the next recapture. These results suggest that Japanese charr exhibit relatively high residency throughout the year, but many fish moved longer distance. The results also suggest the presence of static and mobile components in the charr population. [source] Modification of growing-season surface temperature records in the northern great plains due to land-use transformation: verification of modelling results and implication for global climate changeINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2004Rezaul Mahmood Abstract Land-use and land-cover change can modify near-surface atmospheric condition. Mesoscale modelling studies have shown that modification in land use affects near-surface soil moisture storage and energy balance. Such a study in the Great Plains showed that changes in land use from natural grass to irrigated agriculture enhanced soil water storage in the root zone and increased latent energy flux. This increase in latent energy flux would correspond to a decrease in sensible heat flux and, therefore, modify near-surface temperature records. To verify this deduction, we have investigated the changes in the historical near-surface temperature records in Nebraska, USA. We have analysed the long-term mean monthly maximum, minimum, and monthly mean air temperature data from five irrigated and five non-irrigated sites. The cooperative weather observation (coop) network is the source of the data. We have found that there is a clear trend in decreasing mean maximum and average temperature data for irrigated sites. For example, York, NE, reports that the mean maximum growing season temperature is decreasing at the rate ,0.01°C year,1. The results from non-irrigated sites indicated an increasing trend for the same parameters. The data from Halsey, NE, indicate a +0.01°C year,1 increase in this century. In addition, we have conducted similar analyses of temperature data for the National Climatic Data Center's Historical Climatic Network data set for the same locations. The results are similar to that obtained with the coop data set. Further investigation of dew-point temperature records for irrigated and non-irrigated sites also show an increasing and decreasing trend respectively. Therefore, we conclude that the land-use change in the Great Plains has modified near-surface temperature records. Copyright © 2004 Royal Meteorological Society [source] Backpackers in the Northern Territory of Australia,motives, behaviours and satisfactionsINTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 2 2003Asad Mohsin Abstract This paper reports the findings of a study of 475 backpackers in the Northern Territory of Australia. It finds that backpackers tend to visit many of the same locations as other tourists, and like those tourists, are attracted to the natural sights of the Territory. It is also found that the backpackers can be divided into various groups. For example, of this sample about one-third had left their previous career to travel, and about 12% had just completed studies. On the other hand about one-quarter were holidaying during periods of normal paid holiday leave. It is argued that the market is not solely comprised of ,life change' or rite de passage holidaymakers. Additionally, differences are found between national groupings. Copyright © 2003 John Wiley & Sons, Ltd. [source] Neurocalcin-like immunoreactivity in embryonic stages of the gastropod molluscs Aplysia californica and Lymnaea stagnalisINVERTEBRATE BIOLOGY, Issue 3 2001Amanda J.G. Dickinson Neurocalcin is a calcium-binding protein that has been localized in neural and non-neural tissues of vertebrates, the arthropod Drosophila melanogaster, and in juveniles and adults of the mollusc Aplysia californica. We examine the distribution of neurocalcin in pre-hatching stages of the molluscs A. californica and Lymnaea stagnalis to elucidate where this calcium-binding protein functions in early development, as well as to localize novel neuronal populations in early stages of ontogeny. Aplysia neurocalcin (ApNc)-like immunoreactivity was localized in shell-secreting cells in embryonic stages of both A. californica and L. stagnalis. In A. californica, central and anterior regions of the embryo were diffusely labeled, as were a few identifiable neurons in veliger stages, On the other hand, in L. stagnalis, ApNc-like immunoreactivity was clearly detected in cells and fibers in the same locations as neuronal elements that have been previously identified very early in development and throughout the embryonic period using techniques to localize specific transmitters and peptides. Furthermore, additional neurons are also identified with anti- ApNc in this species. Establishing the distribution of neurocalcin-like proteins in embryonic stages of these two molluscs provides the first step to understanding the role of such proteins during development. [source] Kootenai River velocities, depth, and white sturgeon spawning site selection , a mystery unraveled?JOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2009V. L. Paragamian Summary The Kootenai River white sturgeon Acipenser transmontanus population in Idaho, US and British Columbia (BC), Canada became recruitment limited shortly after Libby Dam became fully operational on the Kootenai River, Montana, USA in 1974. In the USA the species was listed under the Endangered Species Act in September of 1994. Kootenai River white sturgeon spawn within an 18-km reach in Idaho, river kilometer (rkm) 228.0,246.0. Each autumn and spring Kootenai River white sturgeon follow a ,short two-step' migration from the lower river and Kootenay Lake, BC, to staging reaches downstream of Bonners Ferry, Idaho. Initially, augmented spring flows for white sturgeon spawning were thought to be sufficient to recover the population. Spring discharge mitigation enhanced white sturgeon spawning but a series of research investigations determined that the white sturgeon were spawning over unsuitable incubation and rearing habitat (sand) and that survival of eggs and larvae was negligible. It was not known whether post-Libby Dam management had changed the habitat or if the white sturgeon were not returning to more suitable spawning substrates farther upstream. Fisheries and hydrology researchers made a team effort to determine if the spawning habitat had been changed by Libby Dam operations. Researchers modeled and compared velocities, sediment transport, and bathymetry with post-Libby Dam white sturgeon egg collection locations. Substrate coring studies confirmed cobbles and gravel substrates in most of the spawning locations but that they were buried under a meter or more of post-Libby Dam sediment. Analysis suggested that Kootenai River white sturgeon spawn in areas of highest available velocity and depths over a range of flows. Regardless of the discharge, the locations of accelerating velocities and maximum depth do not change and spawning locations remain consistent. Kootenai River white sturgeon are likely spawning in the same locations as pre-dam, but post-Libby Dam water management has reduced velocities and shear stress, thus sediment is now covering the cobbles and gravels. Although higher discharges will likely provide more suitable spawning and rearing conditions, this would be socially and politically unacceptable because it would bring the river elevation to or in excess of 537.66 m, which is flood stage. Thus, support should be given to habitat modifications incorporated into a management plan to restore suitable habitat and ensure better survival of eggs and larvae. [source] Leichhardt's maps: 100 years of change in vegetation structure in inland QueenslandJOURNAL OF BIOGEOGRAPHY, Issue 1 2008R. J. Fensham Abstract Aim, To address the hypothesis that there has been a substantial increase in woody vegetation cover (,vegetation thickening') during the 100 years after the burning practices of aboriginal hunter-gatherers were abruptly replaced by the management activities associated with pastoralism in north-east Australia. Location, Three hundred and eighty-three sites on 3000 km transect, inland Queensland, Australia. Methods, Vegetation structure descriptions from the route notes of the first European exploration of the location by Ludwig Leichhardt in 1844,45 were georeferenced and compiled. Leichhardt's application of structural descriptors (e.g. ,scrub', ,open forest', ,plain') was interpreted as domains within a matrix of tall stratum and low stratum woody cover. Woody cover was also interpreted for the same locations using aerial photography that largely pre-dates extensive land clearing (1940s,1970s) and compared with their structural domain in 1844,45. The fire-sensitive tree, cypress-pine (Callitris glaucophylla) was singled out for case study because it has been widely proposed that the density of this tree has substantially increased under European pastoral management. Results, The coarse resolution of this analysis indicates that the structure of the vegetation has been stable over the first 100 years of pastoralism. For example treeless or sparsely treed plains described by Leichhardt (1844,45) had the same character on the aerial photography (1945,78). Leichhardt typically described vegetation that includes cypress-pine as having a ,thicket' structure suggesting dense regenerating stands of small trees, consistent with the signature typical on the aerial photography. Main conclusions, A large data set of geographically located descriptions of vegetation structure from the first European traverse of inland Australia compared with vegetation structure determined from aerial photography does not support the hypothesis that vegetation thickening has been extensive and substantial. On the contrary the study suggests that the structure of the vegetation has been relatively stable for the first 100 years of European settlement and pastoralism except for those areas that have been affected by broad-scale clearing. [source] Reader variability in the use of diagnostic terms to describe white matter lesions seen on cranial scans of severely premature infants: The ELGAN studyJOURNAL OF CLINICAL ULTRASOUND, Issue 8 2010Sjirk Westra MD Abstract Purpose To evaluate reader variability of white matter lesions seen on cranial sonographic scans of extreme low gestational age neonates (ELGANs). Methods In 1,452 ELGANs, cranial sonographic scans were obtained in the first and second postnatal weeks, and between the third postnatal week and term. All sets of scans were read independently by two sonologists. We reviewed the use of four diagnostic labels: early periventricular leucomalacia, cystic periventricular leucomalacia, periventricular hemorrhagic infarction (PVHI), and other white matter diagnosis, by 16 sonologists at 14 institutions. We evaluated the association of these labels with location and laterality of hyperechoic and hypoechoic lesions, location of intraventricular hemorrhage, and characteristics of ventricular enlargement. Results Experienced sonologists differed substantially in their application of the diagnostic labels. Three readers applied early periventricular leucomalacia to more than one fourth of all the scans they read, whereas eight applied this label to ,5% of scans. Five applied PVHI to ,10% of scans, while three applied this label to ,5% of scans. More than one third of scans labeled cystic periventricular leucomalacia had unilateral hypoechoic lesions. White matter abnormalities in PVHI were more extensive than in periventricular leucomalacia and were more anteriorly located. Hypoechoic lesions on late scans tended to be in the same locations, regardless of the diagnostic label applied. Conclusions Experienced sonologists differ considerably in their tendency to apply diagnostic labels for white matter lesions. This is due to lack of universally agreed-upon definitions. We recommend reducing this variability to improve the validity of large multicenter studies. © 2010 Wiley Periodicals, Inc. J Clin Ultrasound 38:409,419, 2010 [source] Interspecific variations of otolith chemistry in estuarine fish nurseriesJOURNAL OF FISH BIOLOGY, Issue 10 2008P. Reis-Santos Otolith chemical composition differed between juveniles of five fish species (Solea solea, Solea senegalensis, Platichthys flesus, Diplodus vulgaris and Dicentrarchus labrax) in nursery areas of six estuaries along the Portuguese coast (Douro, Ria de Aveiro, Mondego, Tejo, Sado and Mira). Spatially consistent patterns in the concentration of some elements were responsible for differences between species. Discrimination of estuaries using data from all species simultaneously averaged 44·7% of correctly classified cases, whilst discrimination of species averaged 76·2%. Moreover, species-related patterns in otolith fingerprints were highlighted when comparing species for each estuarine nursery area, with intra estuarine species discrimination averages ranging from 86·2 to 100·0%. Similarities in the otolith elemental fingerprints were larger between species with close phylogeny and ecology, particularly between flatfish and perciform species. In addition to the differences in physiological regulation of species, specific microhabitat use in a common environment was suggested as a relevant factor for the differentiation of otolith chemistry among species occurring in the same locations. Despite positive results in specific estuaries, variation in otolith composition limited the use of species as proxies to classify others to their system of origin. [source] A measure of food seeking in individuals with Prader,Willi syndromeJOURNAL OF INTELLECTUAL DISABILITY RESEARCH, Issue 1 2006J. Young Abstract Background Individuals with Prader,Willi syndrome (PWS), a chromosome 15 genetic disorder, often have a significant preoccupation with food and problem behaviour related to food seeking is often prevalent. Methods In the present study, we compared how individuals with PWS responded on a survey regarding the acceptability of food in various locations that varied according to degree of appropriateness for human consumption (e.g. food on a plate, food in a garbage can). For a subgroup of participants, we observed how they actually responded when placed in a room with food items placed in the same locations depicted in the survey. In the first part of the study, three groups (25 typically developing individuals, 7 individuals with intellectual disability (ID), and 19 individuals with PWS) responded to a visual survey to determine the degree of acceptability of food items in various locations (e.g. on a table near a hairbrush, on the floor behind a toy box, in a trash can). In the second part of the study, these food items (popcorn, jelly beans) were placed in the 12 locations described above. Nine individuals diagnosed with PWS (deletion type) and three individuals with ID were given some break time in the room for 15 min. The amount of food consumed, the time spent food seeking, and time spent interacting with materials were measured. Results Results of the survey indicated that the PWS group differed significantly with regard to how they responded on the survey from the typically developing group, but did not differ significantly from the ID group. Results of the food seeking observations indicated that only three individuals with PWS ate a significant number of items. The three individuals did not differ from the rest of the group according to IQ or compulsivity score; however, they had significantly lower body mass index (BMI) scores and were younger than the other participants. Conclusions The findings from the survey indicate that individuals with PWS are able to discriminate the appropriateness of eating items in more or less contaminated areas; however, the amount of time spent seeking food and the amount of food covertly consumed appeared to depend more directly on age and BMI. [source] Introduction to the special issue on Bayesian journey-to-crime modellingJOURNAL OF INVESTIGATIVE PSYCHOLOGY AND OFFENDER PROFILING, Issue 3 2009Ned Levine Abstract In this special issue of the Journal of Investigative Psychology and Offender Profiling, we explore a Bayesian approach to journey-to-crime (JTC) estimation with an emphasis on the statistical models used. The approach conceptualises the probability that an offender lives at one location as the product of the probability distribution from a JTC estimate along with the probability distribution of other offenders who committed crimes in the same locations. The Bayesian approach is appropriate as the second part is conditional on the first part. The introduction gives the background behind the methodology and suggests how future improvements can be made by integrating new information. Finally, the papers in the special issue are introduced. Copyright © 2009 John Wiley & Sons, Ltd. [source] Initial feasibility of a multi-station high resolution three-dimensional dark blood angiography protocol for the assessment of peripheral arterial diseaseJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2009Georgeta Mihai PhD Abstract Purpose To evaluate the feasibility of a multi-station three dimensional (3D) T1-weighted turbo spin echo (TSE) dark-blood Sampling Perfection with Application optimized Contrasts using different flip angle Evolution sequence (T1w-SPACE), to assess aorta, iliac, and superficial femoral (SFA) arteries (inflow vessels) by comparing it with a multi-station contrast enhanced MR angiography (CE-MRA) with identical resolution. Materials and Methods A total of 6 volunteers and 14 peripheral arterial disease (PAD) patients were included in the study. Abdominal and thigh T1w-SPACE and lower leg time-resolved MRA (TR-MRA) with low dose contrast were followed by 3-station CE-MRA. Quantitative measurements of lumen area at 17 locations from T1w-SPACE and CE-MRA were obtained. Additionally, vessel wall areas at the same locations were obtained from the T1w-SPACE images. Results Quantitative comparison of lumen areas with T1w-SPACE and CE-MRA revealed strong correlation between the two techniques and strong inter-observer agreement for each of the two imaging methods (r > 0.9; P < 0.001). Localized vessel wall area measurements obtained in PAD patients were significantly greater compared with those obtained in normal volunteers (mean difference 43.75 ± 12.46 mm2; P < 0.001). Stenosis severity obtained from T1w-SPACE localized measurements showed significant arterial area stenosis in PAD patients. Conclusion T1w-SPACE imaging of inflow vessels is feasible, and in addition to CE-MRA has the ability to assess atherosclerotic plaque and vascular remodeling. J. Magn. Reson. Imaging 2009;30:785,793. © 2009 Wiley-Liss, Inc. [source] Microbial status in seawater and coastal sediments during pre- and post-tsunami periods in the Bay of Bengal, IndiaMARINE ECOLOGY, Issue 3 2006Subramani Ramesh Abstract Tsunami, the natural disaster, which occurred on December 26, 2004 in the Indian Ocean, caused severe damage to mankind in the coastal areas. Total loss of life and economic loss because of this disaster have been estimated by various agencies but its effect on microbial density has not been probed. With our previous results on microbial populations in four locations of the Chennai coast of the Bay of Bengal, India in the pre-tsunami period, the change in microbial populations was studied after the tsunami at regular intervals in the same locations. Coastal sediment and seawater samples were collected from four different locations after 5,10 h and thereafter at intervals of every 7 days up to 28 days post-tsunami. Bacteria, fungi and actinomycetes were isolated from the marine samples by serial dilution on respective media. Before the tsunami, the bacterial population was higher in seawater samples than the sediments, whereas fungi and actinomycetes were recorded only in the sediments. The microbial population remarkably increased 5,10 h post-tsunami in all the marine samples irrespective of the location. However, it slowly declined in the subsequent days and became similar to that of the population recorded before the tsunami. The population of gram-positive bacteria increased whereas the gram-negative bacterial population decreased after the tsunami. Further, populations of pathogenic bacteria such as coliform and vibrios did not increase after the tsunami. It has been observed that the increase in populations of bacteria and actinomycetes even after 28 days of tsunami may be due to the introduction of foreign microorganisms that developed the ability to survive in the extreme environment by exhibiting special characteristics such as pigmentation and production of exopolysaccharides. [source] Long-term geobotanical observations of climate change impacts in the Scandes of West-Central SwedenNORDIC JOURNAL OF BOTANY, Issue 4 2004Leif Kullman In the context of projected future human-caused climate warming, the present study reports and analyses the performance of subalpine/alpine plants, vegetation and phytogeographical patterns during the past century of about 1 °C temperature rise. Historical baseline data of altitudinal limits of woody and non-woody plants in the southern Scandes of Sweden are compared with recent assessments of these limits at the same locations. The methodological approach also includes repeat photography, individual age determinations and analyses of permanent plots. At all levels, from trees to tiny herbs, and from high to low altitudes, the results converge to indicate a causal association between temperature rise and biotic evolution. The importance of snow cover phenology is particularly evident. Treeline advance since the early-20th century varies between 75 and 130 m, depending on species and site. Tendencies and potentials for further upshift in a near future are evident from the appearance of young saplings of all tree species, growing 400,700 m atop of the treeline. Subalpine/alpine plant species have shifted upslope by average 200 m. In addition, present-day repetitions of floristic inventories on two alpine mountain summits reveal increases of plant species richness by 58 and 67%, respectively, since the early-1950s. Obviously, many plants adjust their altitudinal ranges to new climatic regimes much faster than generally assumed. Nevertheless, plants have migrated upslope with widely different rates. This produces non-analogous alpine plant communities, i.e. peculiar mixtures of alpine and silvine species. The alpine region is shrinking (higher treeline), and the character of the remaining alpine vegetation landscape is changing. For example, extensive alpine grasslands are replacing snow bed plant communities. [source] Permafrost distribution in talus slopes located within the alpine periglacial belt, Swiss AlpsPERMAFROST AND PERIGLACIAL PROCESSES, Issue 3 2008Christophe Lambiel Abstract The extent of permafrost in nine talus slopes located within the alpine periglacial belt in the western Swiss Alps was investigated using ground surface temperature measurements and one- dimensional geoelectrical profiles. Based on the thermal data, permafrost appears likely in the lower parts of the slopes. At the same locations, an electrically resistive layer, interpreted as frozen sediments, was identified beneath 3,5,m of surface materials. Further upslope, resistivities were lower and ground surface temperatures were warmer, suggesting that permafrost was absent. The cooling of the ground in the lower parts of some of the talus slopes investigated was apparently due to the chimney effect. It is inferred that this mechanism plays an important role in permafrost development in the lower half of talus slopes located within the discontinuous mountain permafrost belt. Copyright © 2008 John Wiley & Sons, Ltd. [source] Archaeogeophysical study on the site of Tell Toukh El-Qaramous, Sharkia Governorate, East Nile Delta, EgyptARCHAEOLOGICAL PROSPECTION, Issue 1 2003H. Ghazala Abstract The archaeological site of Tell Toukh El-Qaramous, which is located to the south of Abu Kebir, Sharkiya Governorate, was subjected to detailed geophysical studies using magnetic vertical gradient and geoelectric resistivity survey. The success of these surveys depends on the contrast in the physical properties between the dominant sedimentary deposits (clays and sands) and the buried archeological constructions. The area of study occupies about 80 acres at present. It was subjected firstly to a regional geophysical survey to discover the subsurface conditions above one of the most important military fortress that had been constructed to be vanguard of the eastern entry to Egypt during the Ptolemaic age (323,30 BC). Detailed gridded magnetic (0.5 m grid interval) and geoelectric resistivity surveys (2 m grid interval) were also carried out at a selected site of about 50 × 100 m according to the recommendations of the archaeologists who periodically carried out excavation of the archaeological remains. Such surveys could help mapping of the anomalous features that probably reflect the buried archaeological remains. The integrated results of the magnetic gradient images obtained as well as apparent resistivity maps for depths ranges from 1 to 5 m gave fascinating results. The results indicate that the Tell-Toukh El-Qaramous has been built on a buried sand gezira. Also, groups of ancients walls made of mud bricks and some interesting locations of archeological buried artefacts have been delineated. Both the magnetic and resistivity data supported each other and are in good agreement for the same locations of archeological interest. Copyright © 2002 John Wiley & Sons, Ltd. [source] Angioarchitecture of the venous and capillary system in heart defects induced by retinoic acid in mice,BIRTH DEFECTS RESEARCH, Issue 7 2009Anna Ratajska Abstract BACKGROUND: Corrosion casting and immunohistochemical staining with anti-alpha smooth muscle actin and anti-CD34 was utilized to demonstrate the capillary plexus and venous system in control and malformed mouse hearts. METHODS: Outflow tract malformations (e.g., double outlet right ventricle, transposition of the great arteries, and common truncus arteriosus) were induced in progeny of pregnant mice by retinoic acid administration at day 8.5 of pregnancy. RESULTS: Although control hearts exhibited areas in which capillaries tended to be oriented in parallel arrays, the orientation of capillaries in the respective areas of malformed hearts was chaotic and disorganized. The major branch of a conal vein in control hearts runs usually from the left side of the conus to its right side at the root of the pulmonary trunk and opens to the right atrium below the right auricle; thus, it has a curved course. On the other hand, a conal vein in malformed hearts courses from the left side or from the anterior side of the conus and tends to traverse straight upwards along the dextroposed aorta or along the aortopulmonary groove with its proximal part located outside of the heart. Other cardiac veins in outflow tract malformations are positioned in the same locations as in control hearts. CONCLUSIONS: We postulate that the changed location of the conal vein and disorganized capillary plexus result from malformed morphogenesis of the outflow tract and/or a disturbed regulation of angiogenic growth factor release from the adjacent environment. Birth Defects Research (Part A), 2009. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||||||||