Ontogenetic niche shifts occur across diverse taxonomic groups, and can have critical implications for population dynamics, community structure, and ecosystem function. In this study, we provide a hypothesis-testing framework combining univariate and multivariate analyses to examine ontogenetic niche shifts using stable isotope ratios. This framework is based on three distinct ...

Understanding how freshwater assemblages have been formed and maintained is a fundamental goal in evolutionary and ecological disciplines. Here we use a historical approach to test the hypothesis of codivergence in three clades of the Chilean freshwater species assemblage. Molecular studies of freshwater crabs (Aegla: Aeglidae: Anomura) and catfish (Trichomycterus ...

In group-living animals, such as primates, the average spatial group structure often reflects the dominance hierarchy, with central dominants and peripheral subordinates. This central-peripheral group structure can arise by self-organization as a result of subordinates fleeing from dominants after losing a fight. However, in real primates, subordinates often avoid interactions ...

Aggression occurs when individuals compete over limiting resources. While theoretical studies have long placed a strong emphasis on context-specificity of aggression, there is increasing recognition that consistent behavioural differences exist among individuals, and that aggressiveness may be an important component of individual personality. Though empirical studies tend to focus on ...

Timing the origin of human malarias has been a focus of great interest. Previous studies on the mitochondrial genome concluded that Plasmodium in primates, including those parasitic to humans, radiated relatively recently during a process where host switches were common. Those investigations, however, assumed constant rate of evolution and tightly ...

The scaling of body parts is a central feature of animal morphology. Within species, morphological traits need to be correctly proportioned to the body for the organism to function; larger individuals typically have larger body parts and smaller individuals generally have smaller body parts, such that overall body shape is ...

In this work, belonging to the field of comparative analysis of protein sequences, we focus on detection of functional specialization on the residue level. As the input, we take a set of sequences divided into groups of orthologues, each group known to be responsible for a different function. This provides ...

This study used 16S rRNA-based pyrosequencing to examine the microbial community that is closely associated with the colonic mucosa of five healthy individuals. Spatial heterogeneity in microbiota was measured at right colon, left colon and rectum, and between biopsy duplicates spaced 1 cm apart. The data demonstrate that mucosal-associated microbiota ...

The high diversity of New Caledonia has traditionally been seen as a result of its Gondwanan origin, old age and long isolation under stable climatic conditions (the museum model). Under this scenario, we would expect species diversification to follow a constant rate model. Alternatively, if New Caledonia was completely submerged ...

In a "wasp-waist" ecosystem, an intermediate trophic level is expected to control the abundance of predators through a bottom-up interaction and the abundance of prey through a top-down interaction. Previous studies suggest that the North Sea is mainly governed by bottom-up interactions driven by climate perturbations. However, few studies have ...

Environmental conditions under which species reproduce have major consequences on breeding success and subsequent fitness. Therefore breeding habitat choice is ultimately important. Studies rarely address the potential fitness pay-offs of alternative natural breeding habitats by experimental translocation. Here we present a new tool to study fitness consequences of free living ...

A large body of evidence has shown that anosmic pigeons are impaired in their navigation. However, the role of odours in navigation is still subject to debate. While according to the olfactory navigation hypothesis homing pigeons possess a navigational map based on the distribution of environmental odours, the olfactory activation ...

The emergence of similar collective patterns from different self-propelled particle models of animal groups points to a restricted set of "universal" classes for these patterns. While universality is interesting, it is often the fine details of animal interactions that are of biological importance. Universality thus presents a challenge to inferring ...

The internal braincase anatomy of the holotype of Alioramus altai, a relatively small-bodied tyrannosauroid from the Late Cretaceous of Mongolia, was studied using high-resolution computed tomography. A number of derived characters strengthen the diagnosis of this taxon as both a tyrannosauroid and a unique, new species (e.g., endocranial position of ...

Transplantation is the treatment of choice for people with severe organ failure. However, demand substantially exceeds supply of suitable organs; consequently many people wait months, or years to receive an organ. Reasons for the chronic shortage of deceased organ donations are unclear; there appears to be no lack of 'in ...

The phyllostomid bats present the most extensive ecological and phenotypic radiation known among mammal families. This group is an important model system for studies of cranial ecomorphology and functional optimisation because of the constraints imposed by the requirements of flight. A number of studies supporting phyllostomid adaptation have focused on ...

Intraspecific coalitional aggression between groups of individuals is a widespread trait in the animal world. It occurs in invertebrates and vertebrates, and is prevalent in humans. What are the conditions under which coalitional aggression evolves in natural populations? In this article, I develop a mathematical model delineating conditions where natural ...

In this work kinetic data were obtained for different paraoxon concentrations incubated with chicken serum and the soluble fraction of chicken peripheral nerve. A kinetic model equation was deduced by assuming a multienzymatic system with three different simultaneously occurring molecular phenomena: (1) inhibition; (2) simultaneous spontaneous reactivation; (3) "ongoing" inhibition ...

Human land-use effects on species populations are minimized in protected areas and population changes can thus be more directly linked with changes in climate. In this study, bird population changes in 96 protected areas in Finland were compared using quantitative bird census data, between two time slices, 1981-1999 and 2000-2009, ...

The strategy of relying extensively on stored resources for reproduction has been termed capital breeding and is in contrast to income breeding, where needs of reproduction are satisfied by exogenous (dietary) resources. Most species likely fall somewhere between these two extremes, and the position of an organism along this gradient ...

Live bird markets (LBMs) act as a network 'hub' and potential reservoir of infection for domestic poultry. They may therefore be responsible for sustaining H5N1 highly pathogenic avian influenza (HPAI) virus circulation within the poultry sector, and thus a suitable target for implementing control strategies. We developed a stochastic transmission ...

In the present study, we used the diabetic mouse as a model of delayed wound healing to investigate the effects of human cord blood mesenchymal stem cells (CB-MSC) on wound healing. A delayed wound healing model was used by db/db mice. Study models were divided by an injection of human ...

In the present study, we examined whether bird community composition can predict the annual number of human West Nile virus (WNV) cases on a per county basis in the Colorado Front Range, a region that experienced high numbers of human cases during the early part of the North American epidemic. ...

Mutation of SATB2 causes cleft palate in humans. To understand the role of SATB2 function in palatogenesis, SATB2 analyses in vertebrate model systems will be essential. To facilitate these analyses, we have performed a cross-species comparison of SATB2 structure and function across three vertebrate model systems: mouse, chick, and zebrafish. ...

1. This study is the first to quantitatively compare the structure of feeding behaviour of broilers, ducks and turkeys as recorded by electronic feeders. It tests the hypothesis that this structure is so similar that the same models would be suitable to group the feeding behaviour of these species into ...

Newts have been recognized as an ideal model for body-parts regeneration after traumatic injury since the 18(th) century. However, molecular mechanisms underlying regeneration remain a mystery because of technical limitations. In the current study, to break this obstacle, we established a simple and efficient transgenic protocol for the newt Cynops ...

This paper discusses the benefits and limitations of adaptive sample size re-estimation for phase 3 confirmatory clinical trials. Comparisons are made with more traditional fixed sample and group sequential designs. It is seen that the real benefit of the adaptive approach arises through the ability to invest sample size resources ...

The family of protein deacetylases represented by yeast Sir2 has been the focus of intense investigation because of the longevity activity of Sir2 in yeast, worms and flies. Research in mammals has mainly focused on SIRT1, the closest homologue of Sir2. Emerging evidence from mouse models is yielding a sharper ...

Many soaring bird species migrate southwards in autumn from their breeding grounds in Europe and Central Asia towards their wintering grounds. Our knowledge about interactions between migrating birds, thermal selection during migration and mechanisms that lead to flocking or convergent travel networks is still very limited. To start investigating these ...

Extensive evidence now supports the role of papillary interstitial deposits-Randall's plaques-in the formation of stones in the idiopathic, calcium oxalate stone former. These plaques begin as deposits of apatite in the basement membranes of the thin limbs of Henle's loop, but can grow to become extensive deposits beneath the epithelium ...

Limited knowledge of the genetic causes of male infertility has resulted in few treatment and targeted therapeutic options. Although the ideal approach to identify infertility causing mutations is to conduct studies in the human population, this approach has progressed slowly due to the limitations described herein. Given the complexity of ...

IgA nephropathy is the most common primary chronic glomerulonephritis in the world and was first described by Berger et al. (J Urol Nephrol 74:694-695;1968). Histopathologically, IgA nephropathy is characterized by expansion of the glomerular mesangial matrix with mesangial cell proliferation. Glomeruli typically contain generalized diffuse granular mesangial deposits of IgA ...

Autosomal dominant mutations in the presenilin gene PSEN cause familial Alzheimer's disease (AD), a neurological disorder pathologically characterized by intraneuronal accumulation and extracellular deposition of amyloid-β in plaques and intraneuronal, hyperphosphorylated tau aggregation in neurofibrillary tangles. Presenilins (PS/PSENs) are part of the proteolytic γ-secretase complex, which cleaves substrate proteins within ...

We compare four candidate models (logistic, Gompertz, von Bertalanffy, and extreme value function) for modelling the growth of birds. We fitted the models to two empirical data sets of chick growth (six biometric measurements) of African black oystercatchers Haematopus moquini from South Africa and little stints Calidris minuta from Russia, ...

Branching morphogenesis is a crucial developmental process in which vertebrate organs generate extensive epithelial surface area while retaining a compact size. In the vertebrate submandibular salivary gland, branching morphogenesis is crucial for the generation of the large surface area necessary to produce sufficient saliva. However, in many salivary gland diseases, ...

In regression problems where covariates can be naturally grouped, the group Lasso is an attractive method for variable selection since it respects the grouping structure in the data. We study the selection and estimation properties of the group Lasso in high-dimensional settings when the number of groups exceeds the sample ...

With the advent of mouse models that recapitulate the cellular and molecular pathology of pancreatic neoplasia and cancer, it is now feasible to recruit and deploy these models for the evaluation of various chemopreventive and/or anticancer regimens. The highly lethal nature of pancreatic ductal adenocarcinoma (PDAC) makes multiple areas of ...

The need for mouse models, with their well-developed genetics and similarity to human physiology and anatomy, is clear and their central role in furthering our understanding of human disease is readily apparent in the literature. Mice carrying mutations that alter developmental pathways or cellular function provide model systems for analyzing ...

In the time since its discovery, phosducin's functions have been intensively studied both in vivo and in vitro. Phosducin's most important biochemical feature in in vitro studies is its binding to heterotrimeric G protein βγ-subunits. Data on phosducin's in vivo relevance, however, have only recently been published but expand the ...

Multiplex methodologies enable simultaneous detection of antibodies against several infectious agents allowing sample conservation, cost effectiveness, and amenability to high-throughput/automation. We have previously described a multiplex microbead immunoassay for serodetection of ten, high-priority mouse infectious pathogens. Here, we present a validation of this multiplex diagnostic system using approximately four hundred ...

The cochlear microphonic (CM) can be a useful analytical tool, but many investigators may not be fully familiar with its unique properties to interpret it accurately in mouse models of hearing. The purpose of this report is to develop a model for generation of the CM in wild-type (WT) and ...

• Premise of the study: The study of infra-taxa has historically been considered the study of incipient species. Astragalus lentiginosus Douglas ex Hooker (Fabaceae) is the most taxonomically diverse species in the U. S. flora. To gain insight into the nature of infra-taxa, I ask whether an optimal number of ...

Chronic electrical stimulation via corneal electrodes can rapidly yield large numbers of kindled mice with a seizure phenotype reflective of secondarily generalized partial seizures. The corneal kindled mouse model has been found to be a highly sensitive and efficient screening model for antiepileptic drug (AED) discovery. The present study further ...

To investigate the effects of a heterozygous elastin gene (Eln) abnormality (deletion of one Eln allele) on the structural characteristics of the vocal fold lamina propria using a mouse model of human disease. Cross-sectional between-subjects design. Five mice, four with heterozygous Eln deletions (Eln +/-) serving as an animal model ...

The underlying causes of denervation of the neuromuscular junction and eventual motor neuron death in amyotrophic lateral sclerosis (ALS) have not been resolved. The superoxide dismutase 1 (SOD1)(G93A) mutant mouse is a frequently used animal model of ALS. We hypothesized that resveratrol (RSV), a polyphenolic molecule that enhances mammalian NAD(+)-dependent ...

Genetically-engineered mice with hyperlipidemia are the most widely used atherosclerosis models today, but recent advances in transgenesis open the possibility to create new models in alternative species, such as the rat and pig. It seems relevant at this point in time to review some of the strengths and weaknesses of ...

Duplication or absence of parts of the specialized cardiac conduction system in patients with heterotaxy syndrome causes significant clinical disease, but the mechanistic basis by which embryonic disruption of left-right patterning alters conduction system patterning in these patients is not well understood. We sought to determine whether a mouse model ...

Alzheimer's disease (AD) is characterized by deposition of the amyloid beta (Aβ) peptide in brain parenchyma and vasculature. Several proteins co-deposit with Aβ, including heparan sulphate proteoglycans (HSPG). HSPG have been suggested to contribute to Aβ aggregation and deposition, and may influence plaque formation and persistence by stimulating Aβ fibrillization ...

The availability of molecular and genetic tools has made the mouse the most common animal model for a variety of human diseases in toxicology studies. However, little is known about the factors that will influence the dose delivery to murine lungs during an inhalation study. Among these factors are the ...

Age-related neurodegenerative diseases are largely limited to humans and rarely occur spontaneously in animals. Genetically engineered mouse models recapitulate aspects of the corresponding human diseases and are instrumental in studying disease mechanisms and testing therapeutic strategies. If considered within the range of their validity, mouse models have been predictive of ...