The mobile epibenthic fauna of soft bottoms in the Dutch Delta (south-west Netherlands): spatial structure

During 1989 monthly beam trawl samples were collected at 48 stations in the Dutch Delta. The annual mean densities of the demersal fishes and mobile epibenthic invertebrates at these stations were calculated. These data were then subjected to multivariate statistical techniques for an analysis of the spatial structure of the communities found and to study the relationship between these communities and their environment. The present study confirms the results of HENDERSON (1989) that, given a fairly limited number of environmental variables, mainly salinity and exposure/substratum type, quite accurate predictions of the type of community expected at a certain site can be made. The explicit inclusion of epibenthic invertebrates, a dominant group in most assemblages, in studies mainly targeted at demersal fishes, is strongly recommended. In the Dutch Delta rich and varied communities exist in the Voordelta. A number of groups, such as salmonids, anadromous species and starfish, expected in the Westerschelde are absent or extremely rare probably as a consequence of pollution stress. The Oosterschelde is relatively poor in density terms but has a highly diverse epibenthic fauna dominated by fishes

Neonatal Tolerance Revisited: A Perinatal Window for Aire Control of Autoimmunity

There has long been conceptual and experimental support for, but also challenges to, the notion that the initial period of the immune system's development is particularly important for the establishment of tolerance to self. The display of self-antigens by thymic epithelial cells is key to inducing tolerance in the T lymphocyte compartment, a process enhanced by the Aire transcription factor. Using a doxycycline-regulated transgene to target Aire expression to the thymic epithelium, complementing the Aire knockout in a temporally controlled manner, we find that Aire is essential in the perinatal period to prevent the multiorgan autoimmunity that is typical of Aire deficiency. Surprisingly, Aire could be shut down soon thereafter and remain off for long periods, with few deleterious consequences. The lymphopenic state present in neonates was a factor in this dichotomy because inducing lymphopenia during Aire turnoff in adults recreated the disease, which, conversely, could be ameliorated by supplementing neonates with adult lymphocytes. In short, Aire expression during the perinatal period is both necessary and sufficient to induce long-lasting tolerance and avoid autoimmunity. Aire-controlled mechanisms of central tolerance are largely dispensable in the adult, as a previously tolerized T cell pool can buffer newly generated autoreactive T cells that might emerge

Functional expression and intracellular signaling of UTP-sensitive P2Y receptors in theca-interstitial cells

<p>Abstract</p> <p>Background</p> <p>Purinergic receptors are expressed in the ovary of different species; their physiological roles remain to be elucidated. UTP-sensitive P2Y receptor activity may regulate cell proliferation. The aim of the present work was to study the functional expression of these receptors in theca/interstitial cells (TIC).</p> <p>Methods</p> <p>TIC were isolated by centrifugation in a Percoll gradient. P2Y receptors and cellular markers in TIC were detected by RT-PCR and Western blot. Intracellular calcium mobilization induced by purinergic drugs was evaluated by fluorescence microscopy, phosphorylation of MAPK p44/p42 and of cAMP response element binding protein (CREB) was determined by Western blot and proliferation was quantified by [3H]-thymidine incorporation into DNA.</p> <p>Results</p> <p>RT-PCR showed expression of p2y2r and p2y6r transcripts, expression of the corresponding proteins was confirmed. UTP and UDP, agonists for P2Y2 and P2Y6 receptors, induced an intracellular calcium increase with a maximum of more than 400% and 200% of basal level, respectively. The response elicited by UTP had an EC50 of 3.5 +/- 1.01 μM, while that for UDP was 3.24 +/- 0.82 μM. To explore components of the pathway activated by these receptors, we evaluated the phosphorylation induced by UTP or UDP of MAPK p44 and p42. It was found that UTP increased MAPK phosphorylation by up to 550% with an EC50 of 3.34 +/- 0.92 and 1.41 +/- 0.67 μM, for p44 and p42, respectively; these increases were blocked by suramin. UDP also induced p44/p42 phosphorylation, but at high concentrations. Phosphorylation of p44/p42 was dependent on PKC and intracellular calcium. To explore possible roles of this pathway in cell physiology, cell proliferation and hCG-induced CREB-phosphorylation assays were performed; results showed that agonists increased cell proliferation and prevented CREB-phosphorylation.</p> <p>Conclusion</p> <p>Here, it is shown that UTP-sensitive P2Y receptors are expressed in cultured TIC and that these receptors had the ability to activate mitogenic signaling pathways and to promote cell proliferation, as well as to prevent CREB-phosphorylation by hCG. Regulation of TIC proliferation and steroidogenesis is relevant in ovarian pathophysiology since theca hyperplasia is involved in polycystic ovarian syndrome. Purinergic receptors described might represent an important new set of molecular therapeutic targets.</p

Annihilation of Dipolar Dark Matter to Photons

In this work we study the annihilation of fermionic dark matter, considering it as a neutral particle with nonvanishing magnetic ($M$) and electric ($D$) dipole moments. Effective cross-section of the process $\chi \overline{\chi} \rightarrow \gamma \gamma$ is computed starting from a general form of coupling $\chi \overline{\chi} \gamma$ in the framework of an extension of the Standard Model. By taking into account annihilation of DM pairs into mono-energetic photons, we found that for small masses, $m_\chi \leq 10\,\textrm{GeV}$, an electric dipole moment $\sim 10^{-16}\, \textrm{e cm}$ is required to satisfy the current residual density inferences. Additionally, in order to pin down models viable to describe the physics of dark matter at the early Universe we also constrain our model according to recent measurements of the temperature anisotropies of the cosmic background radiation, we report constraints to the electric and magnetic dipole moments for a range of masses within our model.Comment: 20 pages, 6 figure

Non-Gaussian geostatistical modeling using (skew) t processes

We propose a new model for regression and dependence analysis when addressing spatial data with possibly heavy tails and an asymmetric marginal distribution. We first propose a stationary process with t marginals obtained through scale mixing of a Gaussian process with an inverse square root process with Gamma marginals. We then generalize this construction by considering a skew-Gaussian process, thus obtaining a process with skew-t marginal distributions. For the proposed (skew) t process, we study the second-order and geometrical properties and in the t case, we provide analytic expressions for the bivariate distribution. In an extensive simulation study, we investigate the use of the weighted pairwise likelihood as a method of estimation for the t process. Moreover we compare the performance of the optimal linear predictor of the t process versus the optimal Gaussian predictor. Finally, the effectiveness of our methodology is illustrated by analyzing a georeferenced dataset on maximum temperatures in Australia

Multiple dens invaginatus, mulberry molar and conical teeth : case report and genetic considerations

Dens in dente, also known as dens invaginatus and dilated compound odontoma, is a malformation that can occur on primary, permanent, or supernumerary teeth that is characterized by a deep invagination of the surface of a crown or root covered with enamel. This abnormality in tooth morphology generally affect the maxillary lateral incisors but several cases of multiple dens invaginatus have been reported in the literature. A 15 year-old female patient is reported here presenting five dens invaginatus: four in the permanent mandibular incisors and one in the permanent, maxillary left central incisor, additionally the following dental findings were observed: a permanent mandibular left mulberry molar, molarization of some premolars, several microdontic conoid teeth, retention of five primary teeth, absence of several permanent teeth germs, a macrodontic molar with abnormal roots and several periapical radiolucencies associated to the dens invaginatus. There was no family history of similar dental findings to those observed in the patient. There are several genes that participate in the development of teeth, of those, the following five genes could be implicated as responsible or co-participators for some of the dental anomalies present in this patient: MSX1 (Muscle segment homeobox 1), DLX1 and DLX2 (Distal-less homeobox 1 and 2 genes), PAX9 (Paired box gene) and PITX2 (Pituitary homeobox transciption factor 2)

Annihilation of Dipolar Dark Matter: χχ→γγ

In this work we study the annihilation of dark matter, considering it as a neutral particle with magnetic and/or electric moments not null. The calculation of the effective section of the process χχbar→γγ is made starting from a general form of coupling χ χbar γ in the framework of an extension of the Standard Model. We found, when taking into account an annihilation of DDM-antiDDM to monoenergetic photons, that for small masses, mχ ≤ 0 GeV, an electric dipole moment ~10–6 e cm is required to satisfy the current residual density, while for the range of greater sensitivity of HAWC, 10 TeV &lt; Eg &lt; 20 TeV, the electrical dipole moment must be of the order of 10–8 e cm

Evaluación de cinco genotipos de haba (Vicia faba L.) con seis niveles de fósforo en Tecámac, México

Abstract. During the spring-summer of 2000, the investigation was carried out in field conditions utilizing a design of complete blocks, with 30 treatments and three repetitions with a factorial arrangement. The characteristics evaluated were height of the first legume (apv), final height (af), number of stems (nt), number of grains per legume (ngv), number of legumes per plant (nvp), weight of 100 seeds p(100)s and grain yield (rend). The analysis of variance (anova) revealed significant effects for genotypes in the variables p(100)s**, rend** and apv*. As for the phosphorus, the af and rend presented significant values to 0.05. The interaction gxf was highly significant for the rend. The best variety according to the dms was the v-32 (3.92 t ha-1). The characteristics that influenced the expression of grain yield were: nt, nvp and p(100)s