An avian dominance hierarchy at a supplemental water source in the Patagonian steppe

Birds often compete and engage in interspecific agonistic interactions for access to resources such as food and breeding territories. Based on the observed outcomes from such interactions (i.e., patterns of displacements) dominance hierarchies can be established. Knowing which species can outcompete others for essential resources allows researchers to make predictions about the broader ecological impacts of interspecific interactions. We constructed an interspecific dominance hierarchy of twelve avian species which visited an artificial water source in an arid region of coastal Patagonia, Argentina. Displacements were categorized into four types, based on the behaviors involved in the interaction, and we tested if they could predict the difference in dominance between the interacting species (the difference between calculated dominance coefficients for the two focal species). Indirect displacements, involving only the arrival of the dominant species to the water source without direct aggression toward the subordinate bird, occurred more frequently between species with a large difference in dominance. The most dominant bird observed was the kelp gull (Larus dominicanus), which, due to an increasing population and expanding range, in part due to food supplementation from fisheries waste, is likely to outcompete terrestrial and marine avian species for other scarce resources.Fil: Rabinowicz, Sophie. Cornell University; Estados UnidosFil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Herwood, Tristan. Cornell University; Estados UnidosFil: Lazar, Amanda. Cornell University; Estados UnidosFil: Hein, Benjamin. Cornell University; Estados UnidosFil: Miller, Eliot. Cornell Lab of Ornithology; Estados UnidosFil: Campagna, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Cornell University; Estados Unido

Posterior Segment Approach for Subretinal Transplantation or Injection in the Canine Model

A posterior segment approach for cell transplantation or injection into the subretinal space of the dog has been developed. Controlled penetration to the subretinal space was achieved using a 29-gauge injection cannula, either blunted or with a 30° sharpened bevel, and partially ensheathed with moveable plastic tubing. Depending on the injection volume used, the retina detached, and the fluid was reabsorbed within 1–3 weeks, although for smaller volumes the retina reattached within a matter of days. The optimal injection volume used was between 100 and 150 μl, or two injections of 55 μl each. By ophthalmoscopy following the surgery, it was possible to serially monitor the injection site and retinal bleb through fundus photography. Light microscopy demonstrates the distribution of stable, viable RPE cells in the subretinal space up to 6 months. The transplantation technique developed for the dog is atraumatic and free from any major surgical or clinical complications. It can be readily used to deliver cells or fluids to localized regions of the subretinal space

Successful Xenografts of Second Trimester Human Fetal Brain and Retinal Tissue in the Anterior Chamber of the Eye of Adult Immunosuppressed Rats

Successful xenografting of first trimester human fetal CNS tissue and retina has been reported in the literature. We wished to test the feasibility ofusing the anterior chamber ofthe rat eye to support the development of more mature human fetal xenografts. Here we report on the successful outcome of human brain and retinal transplants. Adult host rats immunosuppressed with cyclosporin A accepted these xenografts and supported their further development. Periodic examination of the host eyes using a direct ophthalmoscope or an ophthalmic slit lamp permitted direct visual monitoring of the health and growth of the transplants. Histologically it was possible to identify neuronal, macroglial, and microglial (macrophage) cell types within the grafts. Mitotic activity and histogenetic differentiation took place. Blood vessels filled with hematic cells were commonly present within the grafts. The walls of these vessels prevented the leakageofhorseradish peroxidase, suggesting the presence of a functional brain-blood barrier in the graft. These results indicate that it is possible to use a small animal model to study normal and pathological phenomena oniate fetal human neural tissues. Our group has already taken advantage of the model to achieve HIV infectivity offetal human brain outside the human body

Intraretinal Transplantation for Rod-Cell Replacement in Light-Damaged Retinas

Blindness from retinal disease is often the consequence of extensive damage to the photoreceptor cell population, while other cell types which form the neural retina are relatively spared. In this setting, transplantation of photoreceptor cells could offer hope for the restoration of some degree of visual function. We testd the feasibility of this approach by transplanting immature retinal cells into the eyes of adult rats affected by late stage phototoxic retinopathy, which are almost totally devoid of photoreceptor cells

Galaxies lacking dark matter produced by close encounters in a cosmological simulation

The standard cold dark matter plus cosmological constant model predicts that galaxies form within dark-matter haloes, and that low-mass galaxies are more dark-matter dominated than massive ones. The unexpected discovery of two low-mass galaxies lacking dark matter immediately provoked concerns about the standard cosmology and ignited explorations of alternatives, including self-interacting dark matter and modified gravity. Apprehension grew after several cosmological simulations using the conventional model failed to form adequate numerical analogues with comparable internal characteristics (stellar masses, sizes, velocity dispersions and morphologies). Here we show that the standard paradigm naturally produces galaxies lacking dark matter with internal characteristics in agreement with observations. Using a state-of-the-art cosmological simulation and a meticulous galaxy-identification technique, we find that extreme close encounters with massive neighbours can be responsible for this. We predict that ~30% of massive central galaxies (with at least 1011 solar masses in stars) harbour at least one dark-matter-deficient satellite (with 108–109 solar masses in stars). This distinctive class of galaxies provides an additional layer in our understanding of the role of interactions in shaping galactic properties. Future observations surveying galaxies in the aforementioned regime will provide a crucial test of this scenario

A many-analysts approach to the relation between religiosity and well-being

The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N=10,535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β=0.120). For the second research question, this was the case for 65% of the teams (median reported β=0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

A Many-analysts Approach to the Relation Between Religiosity and Well-being

The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N = 10, 535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β = 0.120). For the second research question, this was the case for 65% of the teams (median reported β = 0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates

Atrial infarction: Diagnosis and management

Atrial infarction has been a relatively understudied entity. Its incidence by autopsy study has been widely variable, from 0.7% to 42%, with the largest series of 182 patients demonstrating an incidence of 17%. The right atrium is involved five times as often as the left, with the auricle the predominant site in either atria. Clinical atrial infarction may present with supraventricular arrhythmias, atrial rupture, hemodynamic compromise from loss of atrial “kick”, and thromboembolic phenomena. Diagnosis currently is made in an appropriate clinical setting with characteristic PR interval changes. Other noninvasive techniques have shown only limited diagnostic utility, but esophageal echocardiography may prove to be a useful technique in this setting