547 research outputs found
Activity and Diversity of Collembola (Insecta) and Mites (Acari) in Litter of a Degraded Midwestern Oak Woodland
Litter-inhabiting Collembola and mites were sampled using pitfall traps over a twelve-month period from four sub-communities within a 100-acre (40-ha) oak-woodland complex in northern Cook County, Illinois. Sampled locations included four areas where future ecological restoration was planned (mesic woodland, dry-mesic woodland, mesic upland forest, and buckthorn-dominated savanna) and a mesic woodland control that would not be restored. Fifty-eight mite and 30 Collembola taxa were identified out of 5,308 and 190,402 individuals trapped, respectively. There was a significant positive relationship between litter mass and both mite diversity and the ratio of Oribatida to Prostigmata and a significant negative relationship between Collembola diversity and litter. Based on multivariate analysis, Collembola and mite composition differed by sub-community and season interaction
3-hydroxykynurenine suppresses CD4+ T-cell proliferation, induces T-regulatory-cell development, and prolongs corneal allograft survival
Copyright © 2011 Association for Research in Vision and Ophthalmology. This article is available open access through the publisher’s website at the link below.Purpose. IDO (indoleamine 2,3-dioxygenase) modulates the immune response by depletion of the essential amino acid tryptophan, and IDO overexpression has been shown to prolong corneal allograft survival. This study was conducted to examine the effect of kynurenines, the products of tryptophan breakdown and known to act directly on T lymphocytes, on corneal graft survival.
Methods. The effects of kynurenines on T-cell proliferation and death, T-regulatory-cell development, and dendritic cell function, phenotype, and viability were analyzed in vitro. The effect of topical and systemic administration of 3-hydroxykynurenine (3HK) on orthotopic murine corneal allograft survival was examined.
Results. T-lymphocyte proliferation was inhibited by two of the four different kynurenines: 3HK and 3-hydroxyanthranilic acid (3HAA). This effect was accompanied by significant T-cell death. Neither 3HK nor 3HAA altered dendritic cell function, nor did they induce apoptosis or pathogenicity to corneal endothelial cells. Administration of systemic and topical 3HK to mice receiving a fully mismatched corneal graft resulted in significant prolongation of graft survival (median survival of control grafts, 12 days; of treated, 19 and 15 days, respectively; P < 0.0003). While systemic administration of 3HK was associated with a significant depletion of CD4+ T, CD8+ T, and B lymphocytes in peripheral blood, no depletion was found after topical administration.
Conclusions. The production of kynurenines, in particular 3HK and 3HAA, may be one mechanism (in addition to tryptophan depletion) by which IDO prolongs graft survival. These molecules have potential as specific agents for preventing allograft rejection in patients at high rejection risk.Fight for Sight and the Wellcome Trust
Activity and Diversity of Collembola (Insecta) and Mites (Acari) in Litter of a Degraded Midwestern Oak Woodland
Litter-inhabiting Collembola and mites were sampled using pitfall traps over a twelve-month period from four sub-communities within a 100-acre (40-ha) oak-woodland complex in northern Cook County, Illinois. Sampled locations included four areas where future ecological restoration was planned (mesic woodland, dry-mesic woodland, mesic upland forest, and buckthorn-dominated savanna) and a mesic woodland control that would not be restored. Fifty-eight mite and 30 Collembola taxa were identified out of 5,308 and 190,402 individuals trapped, respectively. There was a significant positive relationship between litter mass and both mite diversity and the ratio of Oribatida to Prostigmata and a significant negative relationship between Collembola diversity and litter. Based on multivariate analysis, Collembola and mite composition differed by sub-community and season interaction
Flipping the Classroom to Train Citizen Scientists in Invasive Species Detection and Response
Extension educators are increasingly using flipped classrooms, wherein online content delivery precedes in-person learning. We have applied this approach to two Extension programs in which citizen scientists are trained in early detection of invasive species. Our goal in using the tool of flipped classrooms is to accommodate large amounts of content while focusing classroom time on skills development. In 2017, we assessed efficacy of the flipped classroom through knowledge tests and surveys completed by 174 participants and 106 participants, respectively. Results demonstrated large knowledge gains and high participant satisfaction. We encourage Extension professionals to consider whether use of the flipped classroom format could advance achievement of their programs\u27 learning objectives
Langevin simulations of the out-of-equilibrium dynamics of the vortex glass in high-temperature superconductors
We study the relaxation dynamics of flux lines in dirty high-temperature
superconductors using numerical simulations of a London-Langevin model of the
interacting vortex lines. By analysing the equilibrium dynamics in the vortex
liquid phase we find a dynamic crossover to a glassy non-equilibrium regime. We
then focus on the out-of-equilibrium dynamics of the vortex glass phase using
tools that are common in the study of other glassy systems. By monitoring the
two-times roughness and dynamic wandering we identify and characterize
finite-size effects that are similar, though more complex, than the ones found
in the stationary roughness of clean interface dynamics. The two-times
density-density correlation and mean-squared-displacement correlation age and
their temporal scaling follows a multiplicative law similar to the one found at
criticality. The linear responses also age and the comparison with their
associated correlations shows that the equilibrium fluctuation-dissipation
relation is modified in a simple manner that allows for the identification of
an effective temperature characterizing the dynamics of the slow modes. The
effective temperature is closely related to the vortex liquid-vortex glass
crossover temperature. Interestingly enough, our study demonstrates that the
glassy dynamics in the vortex glass is basically identical to the one of a
single elastic line in a disordered environment (with the same type of scaling
though with different parameters). Possible extensions and the experimental
relevance of these results are also discussed.Comment: 22 pages, 29 figure
Stability of Elastic Glass Phases in Random Field XY Magnets and Vortex Lattices in Type II Superconductors
A description of a dislocation-free elastic glass phase in terms of domain
walls is developed and used as the basis of a renormalization group analysis of
the energetics of dislocation loops added to the system. It is found that even
after optimizing over possible paths of large dislocation loops, their energy
is still very likely to be positive when the dislocation core energy is large.
This implies the existence of an equilibrium elastic glass phase in three
dimensional random field X-Y magnets, and a dislocation free,
bond-orientationally ordered ``Bragg glass'' phase of vortices in dirty Type II
superconductors.Comment: 12 pages, Revtex, no figures, submitted to Phys Rev Letter
Vortex Glass Phase and Universal Susceptibility Variations in Planar Array of Flux Lines
Some of the properties of the low temperature vortex-glass phase of
randomly-pinned flux lines in 1+1 dimensions are studied. The flux arrays are
found to be sensitive to small changes in external parameters such as the
magnetic field or temperature. These effects are captured by the variations in
the magnetic response and noise, which have universal statistics and should
provide an unambiguous signature of the glass phase.Comment: 11 pages and no figures; revtex 3.
Neurobiologic Features of Fibromyalgia Are Also Present Among Rheumatoid Arthritis Patients
Funding: The study recieved support from Pfizer. The funder had no role in study design, data collection, analysis, decision to publish or preparation of the manuscript. The content is solely the responsibility of the authors. Funding Information Pfizer Aptinyx Cerephex ACKNOWLEDGEMENTS: The authors wish to thank all of the patient volunteers. We also thank Mariella D’Allesandro for supporting recruitment and data collection.Peer reviewedPostprin
Patterns of Beta Diversity of Vascular Plants and Their Correspondence With Biome Boundaries Across North America
Understanding why species composition and diversity varies spatially and with environmental variation is a long-standing theme in macroecological research. Numerous hypotheses have been generated to explain species and phylogenetic diversity gradients. Much less attention has been invested in explaining patterns of beta diversity. Biomes boundaries are thought to represent major shifts in abiotic variables accompanied by vegetation patterns and composition as a consequence of long-term interactions between the environment and the diversification and sorting of species. Using North American plant distribution data, phylogenetic information and three functional traits (SLA, seed mass, and plant height), we explicitly tested whether beta diversity is associated with biome boundaries and the extent to which two components of beta diversity—turnover and nestedness—for three dimensions of biodiversity (taxonomic, phylogenetic, and functional)—are associated with contrasting environments and linked to different patterns of historical climatic stability. We found that dimensions of vascular plant beta diversity are strongly coupled and vary considerably across North America, with turnover more influential in biomes with higher species richness and greater environmental stability and nestedness more influential in species-poor biomes characterized by high environmental variability. These results can be interpreted to indicate that in harsher climates with less stability explain beta diversity, while in warmer, wetter more stable climates, patterns of endemism associated with speciation processes, as well as local environmental sorting processes, contribute to beta diversity. Similar to prior studies, we conclude that patterns of similarity among communities and biomes reflects biogeographic legacies of how vascular plant diversity arose and was shaped by historical and ecological processes
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