Stable isotope (δD–δ¹⁸O) relationships of ice facies and glaciological structures within the mid-latitude maritime Fox Glacier, New Zealand

Relationships between stable isotopes (δD–δ¹⁸O), ice facies and glacier structures have hitherto gone untested in the mid-latitude maritime glaciers of the Southern Hemisphere. Here, we present δD–δ¹⁸O values as part of a broader study of the structural glaciology of Fox Glacier, New Zealand. We analyzed 94 samples of δD–δ¹⁸O from a range of ice facies to investigate whether isotopes have potential for structural glaciological studies of a rapidly deforming glacier. The δD–δ¹⁸O measurements were aided by structural mapping and imagery from terminus time-lapse cameras. The current retreat phase was preceded by an advance of 1 km between 1984 and 2009, with the isotopic sampling and analysis undertaken at the end of that advance (2010/11). Stable isotopes from debris-bearing shear planes near the terminus, interpreted as thrust faults, are isotopically enriched compared with the surrounding ice. When plotted on co-isotopic diagrams (δD–δ¹⁸O), ice sampled from the shear planes appears to show a subtle, but distinctive isotopic signal compared with the surrounding clean ice on the lower glacier. Hence, stable isotopes (δD–δ¹⁸O) have potential within the structural glaciology field, but larger sample numbers than reported here may be required to establish isotopic contrasts between a broad range of ice facies and glacier structures

Liver-Targeting of Interferon-Alpha with Tissue-Specific Domain Antibodies

PMCID: PMC3581439This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Stochastic population growth in spatially heterogeneous environments

Classical ecological theory predicts that environmental stochasticity increases extinction risk by reducing the average per-capita growth rate of populations. To understand the interactive effects of environmental stochasticity, spatial heterogeneity, and dispersal on population growth, we study the following model for population abundances in $n$ patches: the conditional law of $X_{t+dt}$ given $X_t=x$ is such that when $dt$ is small the conditional mean of $X_{t+dt}^i-X_t^i$ is approximately $[x^i\mu_i+\sum_j(x^j D_{ji}-x^i D_{ij})]dt$, where $X_t^i$ and $\mu_i$ are the abundance and per capita growth rate in the $i$-th patch respectivly, and $D_{ij}$ is the dispersal rate from the $i$-th to the $j$-th patch, and the conditional covariance of $X_{t+dt}^i-X_t^i$ and $X_{t+dt}^j-X_t^j$ is approximately $x^i x^j \sigma_{ij}dt$. We show for such a spatially extended population that if $S_t=(X_t^1+...+X_t^n)$ is the total population abundance, then $Y_t=X_t/S_t$, the vector of patch proportions, converges in law to a random vector $Y_\infty$ as $t\to\infty$, and the stochastic growth rate $\lim_{t\to\infty}t^{-1}\log S_t$ equals the space-time average per-capita growth rate \sum_i\mu_i\E[Y_\infty^i] experienced by the population minus half of the space-time average temporal variation \E[\sum_{i,j}\sigma_{ij}Y_\infty^i Y_\infty^j] experienced by the population. We derive analytic results for the law of $Y_\infty$, find which choice of the dispersal mechanism $D$ produces an optimal stochastic growth rate for a freely dispersing population, and investigate the effect on the stochastic growth rate of constraints on dispersal rates. Our results provide fundamental insights into "ideal free" movement in the face of uncertainty, the persistence of coupled sink populations, the evolution of dispersal rates, and the single large or several small (SLOSS) debate in conservation biology.Comment: 47 pages, 4 figure

Femoral Stem Displacement in a Patient Suffering Recurrent Dislocations After Hip Hemiarthroplasty: Case Report

Displacement of the femoral component during attempt to closed reduction of a dislocated hip arthroplasty is an exceptionally rare, catastrophic event, which renders operative management obligatory. We report the proximal migration of a femoral stem during attempt to closed reduction in a patient with recurrent postoperative dislocations after hip hemiarthroplasty, and describe successful management by conversion to a standard total hip arthroplasty, retaining the same stem in the existing cement mantle. This illustrative case is reported not only as an extremely rare event, but also to highlight and discuss pitfalls and efficient measures in the management of this complex issue

Resident Memory T Cells (TRM) Are Abundant in Human Lung: Diversity, Function, and Antigen Specificity

Recent studies have shown that tissue resident memory T cells (TRM) are critical to antiviral host defense in peripheral tissues. This new appreciation of TRM that reside in epithelial tissues and mediate host defense has been studied most extensively in skin: adult human skin contains large numbers of functional TRM that express skin specific markers. Indeed, more than twice as many T cells reside in skin as in peripheral blood. This T cell population has a diverse T cell receptor repertoire, and can produce a broad array of cytokines. More recently, we have begun to examine other epithelial tissues for the presence of resident T cells. In the present study, we asked whether analogous populations of resident T cells could be found in human lung. We were able to demonstrate abundant resident T cells in human lung-more than 10 billion T cells were present. Lung T cells were largely of the effector memory T cell (TEM) phenotype, though small numbers of central memory T cells (TCM) and T regulatory cells (Treg) could be identified. Lung T cells had a diverse T cell receptor repertoire and subsets produced IL-17, IL-4, IFNγ, as well as TNFα. A significant number of lung TRM CD4+Th cells produced more than one cytokine, identifying them as “multifunctional” Th1 type cells. Finally, lung TRM, but not TRM resident to skin or T cells from blood, proliferated in response to influenza virus. This work suggests that normal human lung contains large numbers of TRM cells, and these cells are poised to respond to recall antigens previously encountered through lung mucosa. This population of T cells may contribute to the pathogenesis of asthma and other T cell mediated lung diseases

What happens if you single out? An experiment

We present an experiment investigating the effects of singling out an individual on trust and trustworthiness. We find that (a) trustworthiness falls if there is a singled out subject; (b) non-singled out subjects discriminate against the singled out subject when they are not responsible of the distinct status of this person; (c) under a negative frame, the singled out subject returns significantly less; (d) under a positive frame, the singled out subject behaves bimodally, either selecting very low or very high return rates. Overall, singling out induces a negligible effect on trust but is potentially disruptive for trustworthiness

X-ray Absorption and Reflection in Active Galactic Nuclei

X-ray spectroscopy offers an opportunity to study the complex mixture of emitting and absorbing components in the circumnuclear regions of active galactic nuclei, and to learn about the accretion process that fuels AGN and the feedback of material to their host galaxies. We describe the spectral signatures that may be studied and review the X-ray spectra and spectral variability of active galaxies, concentrating on progress from recent Chandra, XMM-Newton and Suzaku data for local type 1 AGN. We describe the evidence for absorption covering a wide range of column densities, ionization and dynamics, and discuss the growing evidence for partial-covering absorption from data at energies > 10 keV. Such absorption can also explain the observed X-ray spectral curvature and variability in AGN at lower energies and is likely an important factor in shaping the observed properties of this class of source. Consideration of self-consistent models for local AGN indicates that X-ray spectra likely comprise a combination of absorption and reflection effects from material originating within a few light days of the black hole as well as on larger scales. It is likely that AGN X-ray spectra may be strongly affected by the presence of disk-wind outflows that are expected in systems with high accretion rates, and we describe models that attempt to predict the effects of radiative transfer through such winds, and discuss the prospects for new data to test and address these ideas.Comment: Accepted for publication in the Astronomy and Astrophysics Review. 58 pages, 9 figures. V2 has fixed an error in footnote

Evolution of predator dispersal in relation to spatio-temporal prey dynamics : how not to get stuck in the wrong place!

Peer reviewedPublisher PD

A wager on the future: a practicable response to HIV pre-exposure prophylaxis (PrEP) and the stubborn fact of process

In this article we focus on public health’s wager on the social implications of a daily antiretroviral pill to prevent HIV, referred to as PrEP (pre-exposure prophylaxis). The wager is shown to rely on modes of inquiry overly tied to what is known of the present in order to predict the future. Although such inquiry is not unusual when social research is called upon to assist health policy, predictive methodologies are unable to appreciate the dynamic and thus indeterminate nature of process. We ask: what mode of inquiry might practicably appreciate that what happens in the present will have a bearing on the future, without foreclosing on unknown possibles? Drawing on speculative and pragmatic philosophy, we reflect on our own qualitative research on PrEP to suggest that conventional methodological approaches can contribute to the future without seeking to determine what it will become