Basis for the Age-related Decline in Intestinal Mucosal Immunity

The elderly are characterized by mucosal immunosenescence and high rates of morbidity and mortality associated with infectious diseases of the intestinal tract. Little is known about how the differentiation of immunoglobulin A (IgA) plasma cells in Peyer's patches (PPs) and their subsequent homing to the small intestinal lamina propria (LP) is affected by aging. Quantitative immunohistochemical analyses demonstrated a 2-fold increase in the number of IgA+ cells in the PPs, coupled with significant declines in the numbers of IgA+ and antibody-positive cells in the intestinal LP of senescent rats compared to young adult animals. These data suggest that aging diminishes the emigration of IgA immunoblasts from these lymphoid aggregates, as well as their migration to the intestinal LP. Flow cytometry and lymphocyte adoptive transfer studies showed 3- to 4-fold age-related declines in the homing of antibody-containing cells and mesenteric lymph node lymphocytes to the small intestines of rhesus macaques and rats, respectively. The number of peripheral blood IgA immunoblasts expressing the homing molecule α4β7 declined 30% in senescent rats. This was accompanied by a >17% decrease in the areal density of LP blood vessels staining positive for the cell adhesion molecule MAdCAM-1. Cumulatively, declines in expression of these homing molecules constitute a substantial age-related diminution of IgA immunoblast homing potential. In vitro antibody secretion by LP plasma cells, i.e. antibody secreted per antibody-positive cell, remains unchanged as a function of donor age. Intestinal mucosal immunosenescence is a consequence of reduced homing of IgA plasma cells to the intestinal LP as a result of declines in homing molecule expression

HOST TRACKING OR RESOURCE TRACKING? THE CASE OF PERIGLISCHRUS WING MITES (ACARINA: SPINTURNICIDAE) OF LEAF-NOSED BATS (CHIROPTERA: PHYLLOSTOMIDAE) FROM MICHOACAN, MEXICO

We examined the issue of host tracking versus resource tracking in spinturnicid wing mites of the genus Periglischrus, which are associated with bats of the family Phyllostomidae. Several lines of evidence suggest that these mites are host tracking, that is they do not respond to environmental factors beyond the body of their host. With one exception only, each host species was infested by only one mite species. In some cases, a mite species infested more than one bat species, but these hosts were always closely related, composing a monophyletic group within our sample. Finally, GIS analyses were used to evaluate the effects of annual precipitation, vegetation, climate, and soils on mite distributions within their host distributions in Michoacán. Those associations having an adequate sample size resulted in non-significance, indicating that the mite distributions did not vary with respect to environmental factors. Additional data and analyses are needed to test each of these findings, as well as to evaluate other environmental factors not tested in this study which may be of importance to mite distribution.Las hipótesis de seguimiento del huesped (host tracking) versus seguimiento de recursos (resource tracking) fueron analizadas en ácaros spinturnícidos del genero Periglischrus, parásitos asociados a los murciélagos de la familia Phyllostomidae. Diferentes líneas de evidencia sugieren que estos ácaros siguen a los huespedes, es decir, que no responden a factores ambientales más alla del cuerpo de los mismos. Con una sola excepción, cada especie huesped fue infectada por una sola especie de ácaro. En algunos casos, una especie de ácaro infectó más de una especie de murciélago, pero siempre estos huespedes fueron especies estrechamente relacionadas, componiendo un grupo monofilético dentro de nuestra muestra. Por último, se usaron análisis por sistema de información geográfica (GIS) para evaluar los efectos de precipitación anual, vegetación, clima y suelos en la distribución de los ácaros dentro de la distribución de sus huespedes en Michoacán. Aquellas asociaciones con un tamaño de muestra adecuado resultaron no significativas, indicando que las distribuciones de los ácaros no varían con respecto a factores ambientales. Datos y análisis adicionales son necesarios para poner a prueba estos resultados, así como para evaluar otros factores ambientales no analizados en este estudio y que pudieran ser de importancia en la determinación de la distribución de los ácaros

Parallel-propagating Fluctuations at Proton-kinetic Scales in the Solar Wind are Dominated by Kinetic Instabilities

We use magnetic helicity to characterise solar wind fluctuations at proton-kinetic scales from Wind observations. For the first time, we separate the contributions to helicity from fluctuations propagating at angles quasi-parallel and oblique to the local mean magnetic field, $\mathbf{B}_0$. We find that the helicity of quasi-parallel fluctuations is consistent with Alfv\'en-ion cyclotron and fast magnetosonic-whistler modes driven by proton temperature anisotropy instabilities and the presence of a relative drift between $\alpha$-particles and protons. We also find that the helicity of oblique fluctuations has little dependence on proton temperature anisotropy and is consistent with fluctuations from the anisotropic turbulent cascade. Our results show that parallel-propagating fluctuations at proton-kinetic scales in the solar wind are dominated by proton temperature anisotropy instabilities and not the turbulent cascade. We also provide evidence that the behaviour of fluctuations at these scales is independent of the origin and macroscopic properties of the solar wind.Comment: Accepted for publication in ApJL. 6 Pages, 3 figures, 1 tabl

Working Futures 2017-2027 : Long-run labour market and skills projections headline report

This report provides a concise overview of Working Futures 2017-2027 results for the UK. It presents historical trends and future prospects by sector for the UK and its constituent nations and the English regions. The prime focus of Working Futures is on the demand for skills as measured by employment by occupation and qualification, although the supply side is also considered. Its prime objective is to provide useful labour market information that can help to inform policy development and strategy around skills, careers and employment, for both policy makers and a much wider audience. The results are intended to provide a sound statistical foundation for reflection and debate among all those with an interest in the demand for and supply of skills. It is aimed at the general reader and focuses on the key messages from this very detailed study. It complements the more detailed outputs and results from the project available from the gov.uk website2 and cover sectors, occupations, geography and qualifications

Degeneracy measures for the algebraic classification of numerical spacetimes

We study the issue of algebraic classification of the Weyl curvature tensor, with a particular focus on numerical relativity simulations. The spacetimes of interest in this context, binary black hole mergers, and the ringdowns that follow them, present subtleties in that they are generically, strictly speaking, Type I, but in many regions approximately, in some sense, Type D. To provide meaning to any claims of "approximate" Petrov class, one must define a measure of degeneracy on the space of null rays at a point. We will investigate such a measure, used recently to argue that certain binary black hole merger simulations ring down to the Kerr geometry, after hanging up for some time in Petrov Type II. In particular, we argue that this hangup in Petrov Type II is an artefact of the particular measure being used, and that a geometrically better-motivated measure shows a black hole merger produced by our group settling directly to Petrov Type D.Comment: 14 pages, 7 figures. Version 2 adds two references

Short-term studies underestimate 30-generation changes in a butterfly metapopulation

Most studies of rare and endangered species are based on work carried out within one generation, or over one to a few generations of the study organism. We report the results of a study that spans 30 generations (years) of the entire natural range of a butterfly race that is endemic to 35 km2 of north Wales, UK. Short-term studies (surveys in single years and dynamics over 4 years) of this system led to the prediction that the regional distribution would be quite stable, and that colonization and extinction dynamics would be relatively unimportant. However, a longer-term study revealed unexpectedly high levels of population turnover (local extinction and colonization), affecting 18 out of the 20 patches that were occupied at any time during the period. Modelling the system (using the 'incidence function model' (IFM) for metapopulations) also showed higher levels of colonization and extinction with increasing duration of the study. The longer-term dynamics observed in this system can be compared, at a metapopulation level, with the increased levels of variation observed with increasing time that have been observed in single populations. Long-term changes may arise from local changes in the environment that make individual patches more or less suitable for the butterfly, or from unusual colonization or extinction events that take metapopulations into alternative states. One implication is that metapopulation and population viability analyses based on studies that cover only a few animal or plant generations may underestimate extinction threats

Hardware Specific Integration Strategy for Impedance-Based Structural Health Monitoring of Aerospace Systems

The Integrated Vehicle Health Management (IVHM) Project, sponsored by NASA's Aeronautics Research Mission Directorate, is conducting research to advance the state of highly integrated and complex flight-critical health management technologies and systems. An effective IVHM system requires Structural Health Monitoring (SHM). The impedance method is one such SHM technique for detection and monitoring complex structures for damage. This position paper on the impedance method presents the current state of the art, future directions, applications and possible flight test demonstrations

Determinants of Newspaper Circulation

This study offers a new approach to the problem of time-series studies and attempts to set up a model to account for the growth in demand for daily newspapers Using U S data on a state-by-state basis for 1850 to 1970, we have used a marketing approach What conditions were necessary for the survival of a daily newspaper? What conditions were conducive to consolidation? What conditions were a barrier to the adoption of social and technological innovation? The data were grouped into geographic and social regions for analysis, using a special case of generalized least squares Independent variables included price as a proportion of per-capita income, percentage of the work force in nonagricultural labor, education, voting, and urbanization. Price proved the most powerful predictor Corrected R2s range from 22636 (m regions where newspaper growth took place very early or late in the period) to 67543 in the Midwest and Southwest The model will be applied to data from the industrialized countries of Western Europe in later workPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67057/2/10.1177_009365028000700101.pd