bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein dynamics studied by neutron scattering
Authors: Gabel Frank , Bicout Dominique , Lehnert Ursula , Tehei Moeava , Weik Martin , Zaccai Giuseppe 
Published: February 2003

1. Introduction 3282. Basic concepts of neutron scattering 3292.1 Introduction 3292.2 Neutron-scattering functions 3312.3 Coherent and incoherent neutron scattering. The particular role of hydrogen in incoherent scattering 3322.4 Total elastic scattering, EISF and mean square displacement (MSD) 3332.5 Quasielastic scattering and relaxation function 3342.6 Inelastic scattering and density of states 3353. Experimental aspects and instruments 3353.1 Energy and space resolution 3353.2 General sample aspects 3353.3 Potential effects of D2O on dynamics 3363.4 Experimental 2H (deuterium) labelling 3364. Physics of protein dynamics 3364.1 Models 3364.2 The dynamical transition 3384.3 Effective force constants 3395. Dynamics of hydrated protein powders 3395.1 First experiments on myoglobin 3405.2 Dynamical transitions in other proteins 3405.3 The role of hydration water 3415.4 Influence of the solvent 3445.5 Diffusional motions within proteins by QENS 3465.6 Inelastic neutron scattering and vibrational spectra 3475.7 Conclusions 3516. Membranes 3526.1 Lipid bilayers 3536.2 BR and the purple membrane (PM) 3536.2.1 The dynamical transition in the PM 3536.2.2 QENS from oriented PM 3546.2.3 Hydration dependence of PM motions 3556.2.4 Local dynamics in PM studied by isotope labelling 3566.2.5 Dynamics of different BR conformations 3577. Protein solutions 3587.1 From powders to solutions 3587.2 Water dynamics and solvent dependence of the dynamical transition in proteins 3598. Comparing neutron scattering with other techniques 3599. Biological relevance 3609.1 Dynamics–activity relations 3609.2 Dynamics–stability relations (adaptation to extreme environments) 3609.3 Protein folding 36110. Acknowledgements 36411. References 364This review of protein dynamics studied by neutron scattering focuses on data collected in the last 10 years. After an introduction to thermal neutron scattering and instrumental aspects, theoretical models that have been used to interpret the data are presented and discussed. Experiments are described according to sample type, protein powders, solutions and membranes. Neutron-scattering results are compared to those obtained from other techniques. The biological relevance of the experimental results is discussed. The major conclusion of the last decade concerns the strong dependence of internal dynamics on the macromolecular environment.
Quantification of badger (Meles meles) sett activity as a method of predicting badger numbers
Authors: Wilson G. J. , Delahay R. J. , de Leeuw A. N. S. , Spyvee P. D. , Handoll D. 
Published: February 2003

AbstractEstimating the size of badger populations at a local scale using direct observation is difficult because of their nocturnal and elusive lifestyle. Methods based on live‐trapping can provide robust estimates of badger numbers, but are very labour‐intensive and expensive. The development of alternative methods to predict badger numbers accurately would provide valuable tools for research and management. Badger setts are distinct structures, which exhibit various signs of activity. The physical appearance of setts has been used in the past as a crude guide to the number of badgers likely to be trapped. In this study, an objective system for quantifying levels of activity at badger setts was developed and related to the number of trapped badgers. Several types of activity were positively associated with badger numbers, although these associations varied seasonally. Furthermore, all individual activity scores, summary indices and combinations of activity types were poor predictors of the number of badgers trapped. This is probably because variations in environmental conditions and badger behaviour confound the relationship between activity and badger numbers.
Home range and habitat use of the kit fox (Vulpes macrotis) in a prairie dog (Cynomys ludovicianus) complex
Authors: List Rurik , Macdonald David W. 
Published: February 2003

AbstractThe largest remaining black‐tailed prairie dog Cynomys ludovicianus towns in North America are in Mexico, where they coexist with the kit fox Vulpes macrotis, providing a unique opportunity to study the relationship between these threatened species. We hypothesized that the presence of prairie dogs would positively affect the kit fox population in our study area in north‐western Mexico, and that these influences would be manifest in home‐range size, density and habitat selection. We estimated fox densities fluctuating from 0.32/km2 to 0.8/km2, and radio‐telemetry revealed minimum convex polygon home ranges averaging 11 km2. These values are within the bounds of estimates from study sites elsewhere. Foxes used mesquite scrub less than expected, but grassland more than expected in relation to availability. Other habitats, including prairie dog towns, were used at random. Most (65.1% of 43) fox dens were in grassland, and were enlarged kangaroo rat Dipodomys spp. (34.9%) or prairie dog (34.9%) burrows. That kit foxes seemed to select grasslands rather than prairie dog towns was unexpected, particularly as prairie dogs are known to be a major component of kit fox diet. Foxes may reduce the amount of time they spend in prairie dog towns to avoid coyotes, which can be responsible for significant swift fox mortality. In our study area, coyotes were more active in prairie dog towns than in the grassland, where they were regularly shot. However, grassland used by kit foxes is a short‐lived product of prairie dog poisoning, which is quickly invaded by scrub, a habitat favoured by coyotes. We conclude that kit fox conservation initiatives in north‐western Mexico should be closely linked to conservation of the prairie dog ecosystem.
Warren building by European rabbits (Oryctolagus cuniculus) in relation to cover availability in a sandy area
Authors: Palomares F. 
Published: February 2003

AbstractWarrens of the wild European rabbit Oryctolagus cuniculus are of concern in the Iberian Peninsula as a way to recover rabbit populations. However, there are no studies on the selection of sites where rabbits build their warrens. Between 1995 and 1997, in addition to warren size (number of entrances), the vegetation characteristics and the occurrence of tree roots in the ground surface occupied by warren entrances in Mediterranean scrubland and pastureland habitats were recorded in a sandy area of the Doñana National Park. Pastureland warrens were about twice as large as warrens in Mediterranean scrubland, and 1.8–1.4 times larger in the first study year than in the other 2 years. Warrens in pastureland were built more between tree roots (13.3–17.8%) than those built in Mediterranean scrubland (0.7–1.8%). In Mediterranean scrubland, most of the ground surface occupied by warren entrances was under tall shrubs (79.7–87.9%), with some under short shrubs (4.5–7.4%). In pastureland, these figures were 2.0–3.8% for tall shrubs, and 17.2–19.8% for short shrubs. Warrens were built between tree roots significantly less than expected in the Mediterranean scrubland, and slightly more than expected in the pastureland. Whereas warren surface was occupied by short shrubs significantly less than expected in the Mediterranean scrubland, the opposite pattern occurred in the pastureland; however, in both habitats tall shrubs were significantly preferred. These results suggest that rabbits may seek protection against collapsing warrens by selecting sites with some supporting structures such as the roots of trees or shrubs. Scrubland vegetation (preferably tall shrubs) should be favoured for medium‐ and long‐term habitat management of areas aimed at supporting large rabbit populations. Furthermore, in sandy areas, some kind of stable ground support and external protection should be provided when creating artificial warrens for rabbits.
Taxonomic status and conservation relevance of the raccoons (Procyon spp.) of the West Indies
Authors: Helgen Kristofer M. , Wilson Don E. 
Published: February 2003

AbstractRaccoons Procyon spp. from New Providence Island in the Bahamas and from Barbados and Guadeloupe in the Lesser Antilles have traditionally been recognized as distinctive species endemic to their respective islands. All three of these ‘species’ currently possess official conservation status of high concern. Bahamian and Guadeloupean raccoons are recognized as endangered species by the World Conservation Union (IUCN), which also considers the Barbados raccoon to be a recently extinct West Indian mammal. However, historical, biogeographic, genetic, and morphological evidence demonstrate that all three West Indian raccoon populations are the result of human‐sponsored introductions from the eastern U.S.A. that have occurred in the past few centuries. Accordingly, these animals should not be considered either conservation priorities or recent losses of biodiversity in the Caribbean. Instead, they may actually represent ecological threats to the insular ecosystems on their respective islands. Procyonid conservation goals must be re‐examined and updated accordingly.
Effects of ultraviolet‐B radiation on metamorphic traits in the common frog Rana temporaria
Authors: Pahkala M. , Merilä J. , Ots I. , Laurila A. 
Published: February 2003

AbstractEffects of ultraviolet‐B (UV‐B) radiation on amphibian embryonic and larval development have been investigated in a number of studies, but the effects on later life‐stages (metamorphosis) have received less attention. Hence, the effects of UV‐B radiation treatments (control (no UV‐B), normal and 26% enhanced levels of UV‐B) on the development of the common frog Rana temporaria embryos from fertilization until metamorphosis were investigated. Survival until metamorphosis was significantly higher among individuals exposed to normal, as compared to individuals sheltered from, UV‐B or those exposed to enhanced levels of UV‐B radiation. There were no effects of normal or enhanced levels of UV‐B radiation on the frequency of developmental anomalies. However, UV‐B radiation delayed the timing of metamorphosis in a dose‐dependent fashion, and the individuals from the normal and enhanced UV‐B treatments metamorphosed at smaller size than those raised in the absence of UV‐B radiation. These results suggest that UV‐B radiation experienced through embryonic and larval stages can have negative effects on the growth and development of R. temporaria. Delayed metamorphosis at reduced size is also likely to lower the fitness during later life‐stages.
Non‐random nestling mortality in northern fulmars: implications for monitoring marine environments
Authors: Gray Catherine M. , Phillips Richard A. , Hamer Keith C. 
Published: February 2003

AbstractChick growth and food provisioning of northern fulmars Fulmarus glacialis were studied at Fair Isle, Shetland, in 2 years of contrasting environmental conditions. Low sandeel Ammodytes marinus availability resulted in very low breeding success in many seabirds in Shetland in 1998, whereas breeding success in 1997 indicated a normal season. Fulmars at Fair Isle experienced lower chick survival in 1998 than in 1997. There were also significant differences in diet and food provisioning in the 2 years; sandeels were the most abundant prey items in 1997, but were completely absent from the diet in 1998. High nestling mortality occurred shortly after hatching in 1998. Those chicks that survived this episode had previously been heavier for their age, and remained heavy throughout development in comparison to chicks in 1997, despite a continued absence of sandeels from the diet. Surviving chicks in 1998 were subsequently fed comparatively small meals at frequent intervals, but with no overall difference in the amount of food delivered. We discuss the implications of differential mortality and resulting growth patterns for the use of seabird breeding parameters to monitor marine environments.
Patterns of helping effort in co‐operatively breeding banded mongooses (Mungos mungo)
Authors: Cant Michael A. 
Published: February 2003

AbstractIn most co‐operative breeding species, some individuals contribute much more to helping behaviour than others. The most well‐established explanation of such variation is based on kin selection and suggests that, in the absence of detectable differences in relatedness, individuals who suffer lower costs for a given level of help should contribute more. Differences in helping effort between dominance/sex categories were investigated in co‐operatively breeding banded mongooses Mungos mungo in Uganda. The most conspicuous form of help in this species is provided by individuals who babysit offspring at the den while the rest of the pack goes off to forage. Across eight groups, the survival rate of pups increased with the average number of babysitters guarding them, consistent with the hypothesis that helpers benefit the brood that they guard. There was no difference between dominant males, subordinate males and breeding females in total contributions to babysitting. Subordinate males, however, contributed more to babysitting in the mornings, which were the longest and presumably the most energetically expensive sessions of the day. In six litters in one well‐studied pack, dominant males and breeding females reduced their contribution to babysitting for the period that females were in oestrus. By contrast, subordinate males increased their contribution to become the main babysitters during this time. These results are consistent with the hypothesis that, where helping conflicts with breeding, individuals with little chance of direct reproduction can help at a lower fitness cost than those with a high probability of successful reproduction.
Algophagus mites (Astigmata: Algophagidae) from the sub‐Antarctic Prince Edward Islands: habitat‐related morphology and taxonomic descriptions
Authors: Marshall David J. , OConnor Barry M. , Pugh Philip J. A. 
Published: February 2003

AbstractFive populations of habitat‐specific, morphologically distinct Algophagus mites (Astigmata: Algophagidae) were found to occur on the sub‐Antarctic Prince Edward islands. Although these mites did not differ among themselves with respect to idiosomal setal characteristics, which were also similar to those of known sub‐Antarctic Algophagus taxa, morphometric analyses revealed leg and idiosomal size differences. In addition to morphometric differences, leg setal positions and porose axillary organ structure, indicated that the morphotypes were taxonomically discrete. The taxa were found to include the known A. antarcticus Hughes, 1955, A. laticollaris Fain, 1974 (new status), a sub‐species of A. semicollaris Fain, 1974, and two new species, A. brachytarsus sp. nov. and A. macrolithus sp. nov. With the exception of A. semicollaris, the taxa are described or redescribed in this paper. Morphological features of the females in particular, and notably leg proportions, claw dimensions, and apodeme positions, corroborate discrete terrestrial (A. brachytarsus and A. macrolithus) and aquatic forms (A. antarcticus, A. laticollaris, and A. semicollaris), and vary in a manner suggesting a functional relationship to habitat occupation by the various taxa.
Grey seal (Halichoerus grypus) pup mortality not explained by local breeding density on North Rona, Scotland
Authors: Twiss S. D. , Duck C. , Pomeroy P. P. 
Published: February 2003

AbstractPre‐weaning pup mortality of grey seals Halichoerus grypus in a breeding colony (North Rona, Scotland, U.K.) was examined in relation to the density of local adult females over two breeding seasons. Accurate, fine‐scale maps of daily seal locations within a GIS database permitted the extraction of measures of female density determined at a range of spatial scales from 5 to 50 m around each pup on the date of death. Adult densities around live pups provided the null distribution of adult densities, which were tested against the distribution of densities where deaths occurred. Pre‐weaning pup mortality at this colony was not related to any of our density measures. The proportion of pups dying each day showed no seasonal trends. Analysis of topographic features from a sub‐meter digital terrain model for locations where deaths occurred suggested that there were fewer mortalities in prime pupping habitats. This could have been a direct effect of habitat or the relative quality of mothers in these habitats. The distance separating mothers and pups tended to be greater on the periphery of the colony compared to more central areas. Pups in the peripheral areas may be more exposed to predation by gulls.
When does a reproducing female viper (Vipera aspis) ‘decide’ on her litter size?
Authors: Lourdais Olivier , Bonnet Xavier , Shine Richard , Taylor Emily N. 
Published: February 2003

AbstractSome organisms rely on stored energy to fuel reproductive expenditure (capital breeders) whereas others use energy gained during the reproductive bout itself (income breeders). Most species occupy intermediate positions on this continuum, but few experimental data are available on the timescale over which food intake can affect fecundity. Mark–recapture studies of free‐ranging female aspic vipers Vipera aspis have suggested that reproductive output relies not only on the energy in fat bodies accumulated in previous years, but also on food intake immediately before ovulation. A simple experiment was conducted to test this hypothesis, maintaining female snakes in captivity throughout the vitellogenic period and controlling their food intake. The energy input of a female strongly influenced the amount of mass that she gained and the number of ova that she ovulated. Multiple regression showed that litter size in these snakes was affected both by maternal body condition in early spring (an indicator of foraging success over previous years) and by food intake in the spring before ovulation. Our experimental data thus reinforce the results of descriptive studies on free‐ranging snakes, and emphasize the flexibility of energy allocation patterns among vipers. Reproducing female vipers may combine energy from ‘capital’ and ‘income’ to maximize their litter sizes in the face of fluctuating levels of prey abundance.
A remarkable young Scolecomorphus vittatus (Amphibia: Gymnophiona: Scolecomorphidae) from the North Pare Mountains, Tanzania
Authors: Loader Simon P. , Wilkinson Mark , Gower David J. , Msuya Charles A. 
Published: February 2003

AbstractA description is given of the external morphology of a single young caecilian (gymnophionan) amphibian from the North Pare Mountains, Tanzania, referable to Scolecomorphus vittatus (Boulenger, 1895). This is the smallest known free‐living Scolecomorphus, and it is characterized by many remarkable features previously unrecorded for any life‐history stage of any caecilian. The cheeks have conspicuous, posteroventrally divergent paraoral processes that border a concavity on the ventral surface of the snout. The mandibles are very flexible about their articulation with the cranium, and they have a broader curvature than the upper jaw. The dentition is heterogeneous, with adult‐like monocusped teeth in single rows, but also some supernumerary teeth, some of which are bicornute. The posterior parts of the paraoral processes bear a small number of monocuspid teeth that lie outside, and project away from, the mouth. The nuchal region of the body bears a distinctive concavity on the underside of the throat, bordered by longitudinal ridges that terminate in fleshy nipples. All of these features are unknown in adult Scolecomorphus, and many are unique for caecilians, and they suggest a highly distinctive life‐history stage. The discovery and description of this specimen adds substantially to the currently meagre information on the life history of scolecomorphids and of the diversity of caecilian reproductive biology. Two modes of viviparity in caecilians are identified, with S. vittatus resembling the caeciliid Geotrypetes in giving birth to small altricial young that seem to require extended post‐parturition parental care.
Size and growth of the crabeater seal Lobodon carcinophagus (Mammalia: Carnivora)
Authors: Laws R. M. , Baird A. , Bryden M. M. 
Published: February 2003

AbstractGrowth in length and weight of a large sample of crabeater seals Lobodon carcinophagus collected over the period 1967–78 is reported. Growth in dorsal standard length of 1146 seals (490 males, 656 females) from 0.5 to 20 years of age was similar to the pattern seen in other phocid seals. Length was plotted against age and Gompertz curves fitted to the data. Growth rates were estimated from the derived equations: males, y= 231.9 − 58.7 e−0.55t; females, y= 236.8 − 63.6 e−0.44t. The asymptote is at approximate length 234 cm and age 10 years in both males and females. Body weights were recorded for 249 seals aged from 0.5 to 20 years, of which reliable age estimates for 230 (100 males, 130 females) were available. Rates of growth in body weight were estimated from the derived equations: males, y= 200.0 − 94.1 e−0.48t; females y= 212.4 − 116.2 e−0.40t. The best estimate of body weight from linear body measurements is obtainable from a predictive equation relating body weight, length and axillary girth, determined by maximum likelihood: W = 0.000046 LG2 (W, body weight; L, dorsal standard length; G, axillary girth). There was no significant difference between the sexes. Seasonal variations in body condition could not be determined because all animals were sampled in February and March. However, inter‐year differences in recovery of body condition of adults, following the demands of breeding and moulting in the spring and summer, were observed. The data represent a unique time series covering the 1960s and 1970s. In terms of global climate change they should provide a valuable baseline for future studies.
Miombo woodland termite mounds: resource islands for small vertebrates?
Authors: Fleming Patricia A. , Loveridge John P. 
Published: February 2003

Abstract Macrotermes mounds are a significant feature of African woodland landscape, contributing to habitat heterogeneity. The mounds are massive, often many centuries old, and support dense vegetation and a suite of woody plant species scarce in surrounding woodland. The present study tested the hypothesis that Zimbabwean Macrotermes mounds, with their greater niche availability, were more heavily utilized by small vertebrates than the surrounding miombo woodland. We carried out a survey of amphibian, reptile and mammal species during early and late rains for 16 termite mounds and 16 adjacent woodland habitat sites, and compared numbers of individuals, species and diversity. For amphibians and reptiles, individual numbers and species did not differ significantly between habitats and their activity was more influenced by season. For mammals, however, significantly more individuals and species were captured on termite mounds, with three species captured only on mounds (most notably the musk shrew Crocidura hirta spp. complex) and all others showing marked preference for this habitat. The greater number of mammals on termite mounds contributed to total small vertebrate biomass being 800 g/ha for termite mounds compared with 380 g/ha in woodland. For mammals certainly, Macrotermes mounds provide significant food and habitat in miombo woodland.