Stellar Disk Truncations: Where do we stand ?

In the light of several recent developments we revisit the phenomenon of galactic stellar disk truncations. Even 25 years since the first paper on outer breaks in the radial light profiles of spiral galaxies, their origin is still unclear. The two most promising explanations are that these 'outer edges' either trace the maximum angular momentum during the galaxy formation epoch, or are associated with global star formation thresholds. Depending on their true physical nature, these outer edges may represent an improved size characteristic (e.g., as compared to D_25) and might contain fossil evidence imprinted by the galaxy formation and evolutionary history. We will address several observational aspects of disk truncations: their existence, not only in normal HSB galaxies, but also in LSB and even dwarf galaxies; their detailed shape, not sharp cut-offs as thought before, but in fact demarcating the start of a region with a steeper exponential distribution of starlight; their possible association with bars; as well as problems related to the line-of-sight integration for edge-on galaxies (the main targets for truncation searches so far). Taken together, these observations currently favour the star-formation threshold model, but more work is necessary to implement the truncations as adequate parameters characterising galactic disks.Comment: LaTeX, 10 pages, 6 figures, presented at the "Penetrating Bars through Masks of Cosmic Dust" conference in South Africa, proceedings published by Kluwer, and edited by Block, D.L., Freeman, K.C., Puerari, I., & Groess, R; v3 to match published versio

Galactic Evolution along the Hubble Sequence

A generalization of the multiphase chemical evolution model applied to a wide set of theoretical galaxies is shown. This set of models has been computed by using the so-called Universal Rotation Curve from Persic, Salucci & Steel to calculate the radial mass distributions of each theoretical galaxy. By assuming that the molecular cloud and star formation efficiencies depend on the morphological type of each galaxy, we construct a bi-parametric grid of models whose results are valid in principle for any spiral galaxy, of given maximum rotation velocity or total mass, and morphological type.Comment: Proceedings of the Euroconference "The Evolution of Galaxies. III..." (Kiel 2002

Psychophysiological effects of massage-myofascial release after exercise: a randomized sham-control study

This is a copy of an article published in the Journal of Alternative and Complementary Medicine © 2008 Mary Ann Liebert, Inc.; Journal of Alternative and Complementary Medicine is available online at: http://online.liebertpub.com.Objective: The aim of this study was to evaluate the effect of massage on neuromuscular recruitment, mood state, and mechanical nociceptive threshold (MNT) after high-intensity exercise. Design: This was a prospective randomized clinical trial using between-groups design. Setting: The study was conducted at a university-based sports medicine clinic. Participants: Sixty-two (62) healthy active students age 18–26 participated. Interventions: Participants, randomized into two groups, performed three 30-second Wingate tests and immediately received whole-body massage-myofascial induction or placebo (sham ultrasound/magnetotherapy) treatment. The duration (40 minutes), position, and therapist were the same for both treatments. Main outcome measures: Dependent variables were surface electromyography (sEMG) of quadriceps, profile of mood states (POMS) and mechanical nociceptive threshold (MNT) of trapezius and masseter muscles. These data were assessed at baseline and after exercise and recovery periods. Results: Generalized estimating equations models were performed on dependent variables to assess differences between groups. Significant differences were found in effects of treatment on sEMG of Vastus Medialis (VM) (p 0.02) and vigor subscale (p 0.04). After the recovery period, there was a significant decrease in electromyographic (EMG) activity of VM (p 0.02) in the myofascial-release group versus a nonsignificant increase in the placebo group (p 0.32), and a decrease in vigor (p 0.01) in the massage group versus no change in the placebo group (p 0.86). Conclusions: Massage reduces EMG amplitude and vigor when applied as a passive recovery technique after a high-intensity exercise protocol. Massage may induce a transient loss of muscle strength or a change in the muscle fiber tension–length relationship, influenced by alterations of muscle function and a psychological state of relaxation.The trial was funded by a research project grant (11/UPB10/06) from the Spanish Higher Sports Council

First evidence of population genetic structure of the deep-water blackmouth catshark Galeus melastomus Rafinesque, 1810

Genetic connectivity at large spatial scales. Given the lack of species-specific nuclear markers, a total of 129 microsatellite loci (Simple Sequence Repeats, SSRs) were cross-amplified on blackmouth catshark specimens collected in eight geographically distant areas in the Mediterranean Sea and North-eastern Atlantic Ocean. A total of 13 SSRs were finally selected for genotyping, based on which the species exhibited signs of weak, but tangible genetic structure. The clearcut evidence of genetic differentiation of G. melastomus from Scottish waters from the rest of the population samples was defined, indicating that the species is genetically structured in the Mediterranean Sea and adjacent Southern North-eastern Atlantic. Both individual and frequency-based analyses identified a genetic unit formed by the individuals collected in the Tyrrhenian Sea and the Strait of Sicily, distinguished from the rest of the Mediterranean and Portuguese samples. In addition, Bayesian analyses resolved a certain degree of separation of the easternmost Aegean sample and the admixed nature of the other Mediterranean and the Portuguese samples. Here, our results supported the hypothesis that the interaction between the ecology and biology of the species and abiotic drivers such as water circulations, temperature and bathymetry may affect the dispersion of G. melastomus, adding new information to the current knowledge of the connectivity of this deep-water species and providing powerful tools for estimating its response to anthropogenic impacts

Rheumatoid synovial fluid interleukin-17-producing CD4 T cells have abundant tumor necrosis factor-alpha co-expression, but little interleukin-22 and interleukin-23R expression

Introduction\ud Th17 cells have been implicated in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to systematically analyse the phenotype, cytokine profile and frequency of interleukin-17 (IL-17) producing CD4-positive T cells in mononuclear cells isolated from peripheral blood, synovial fluid and synovial tissue of RA patients with established disease, and to correlate cell frequencies with disease activity. \ud \ud Methods\ud Flow cytometry was used to analyse the phenotype and cytokine production of mononuclear cells isolated from peripheral blood (PBMC) (n = 44), synovial fluid (SFMC) (n = 14) and synovium (SVMC) (n = 10) of RA patients and PBMC of healthy controls (n = 13). \ud \ud Results\ud The frequency of IL-17-producing CD4 T cells was elevated in RA SFMC compared with RA PBMC (P = 0.04). However, the frequency of this population in RA SVMC was comparable to that in paired RA PBMC. The percentage of IL-17-producing CD4 T cells coexpressing tumor necrosis factor alpha (TNFα) was significantly increased in SFMC (P = 0.0068). The frequency of IFNγ-producing CD4 T cells was also significantly higher in SFMC than paired PBMC (P = 0.042). The majority of IL-17-producing CD4 T cells coexpressed IFNγ. IL-17-producing CD4 T cells in RA PBMC and SFMC exhibited very little IL-22 or IL-23R coexpression. \ud \ud Conclusions\ud These findings demonstrate a modest enrichment of IL-17-producing CD4 T cells in RA SFMC compared to PBMC. Th17 cells in SFMC produce more TNFα than their PBMC counterparts, but are not a significant source of IL-22 and do not express IL-23R. However, the percentage of CD4 T cells which produce IL-17 in the rheumatoid joint is low, suggesting that other cells may be alternative sources of IL-17 within the joints of RA patients. \ud \u

Assessment of Darkling Beetle Fauna after Implementation of an Environmental Restoration Program in the Southern Iberian Peninsula Affected by the Aznalcóllar Toxic Spill

This study is part of the Follow up Restoration Program of animal communities that colonize the Guadiamar River Basin. In 1998, the area was affected by a release of toxic sludge after the retention walls of the Aznalcóllar Mines (southern Iberian Peninsula) broke. The main objective of this study was to assess the current state of the population of Tenebrionidae, one of the most representative groups of edaphic Coleoptera inhabiting the Guadiamar River Basin. This paper analyses the progress made by the darkling beetle community six years after the disaster occurred and the Restoration Program was implemented. The study is based on faunistic data from systematic sampling carried out for six years to monitor plots distributed across the damaged area. To make an overall assessment of the tenebrionid fauna in relation to adjacent areas qualitative and quantitative ecological indices were applied, and temporal follow up and biogeographical comparisons were also made. The results indicate that, on the whole, tenebrionid fauna was somewhat affected by the Aznalcóllar Mine spill, and that a greater loss of fauna was detected closer to the accident site. The analysis of the temporal population dynamic suggests that the most affected zones are undergoing a process of re-colonization. However, this process varies widely by species and has not yet reached the expected levels of a non-affected river basin in the southern Iberian Peninsula

Seasonal changes in patterns of gene expression in avian song control brain regions.

This 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.Photoperiod and hormonal cues drive dramatic seasonal changes in structure and function of the avian song control system. Little is known, however, about the patterns of gene expression associated with seasonal changes. Here we address this issue by altering the hormonal and photoperiodic conditions in seasonally-breeding Gambel's white-crowned sparrows and extracting RNA from the telencephalic song control nuclei HVC and RA across multiple time points that capture different stages of growth and regression. We chose HVC and RA because while both nuclei change in volume across seasons, the cellular mechanisms underlying these changes differ. We thus hypothesized that different genes would be expressed between HVC and RA. We tested this by using the extracted RNA to perform a cDNA microarray hybridization developed by the SoNG initiative. We then validated these results using qRT-PCR. We found that 363 genes varied by more than 1.5 fold (>log(2) 0.585) in expression in HVC and/or RA. Supporting our hypothesis, only 59 of these 363 genes were found to vary in both nuclei, while 132 gene expression changes were HVC specific and 172 were RA specific. We then assigned many of these genes to functional categories relevant to the different mechanisms underlying seasonal change in HVC and RA, including neurogenesis, apoptosis, cell growth, dendrite arborization and axonal growth, angiogenesis, endocrinology, growth factors, and electrophysiology. This revealed categorical differences in the kinds of genes regulated in HVC and RA. These results show that different molecular programs underlie seasonal changes in HVC and RA, and that gene expression is time specific across different reproductive conditions. Our results provide insights into the complex molecular pathways that underlie adult neural plasticity

Shape, Size, and Robustness: Feasible Regions in the Parameter Space of Biochemical Networks

The concept of robustness of regulatory networks has received much attention in the last decade. One measure of robustness has been associated with the volume of the feasible region, namely, the region in the parameter space in which the system is functional. In this paper, we show that, in addition to volume, the geometry of this region has important consequences for the robustness and the fragility of a network. We develop an approximation within which we could algebraically specify the feasible region. We analyze the segment polarity gene network to illustrate our approach. The study of random walks in the parameter space and how they exit the feasible region provide us with a rich perspective on the different modes of failure of this network model. In particular, we found that, between two alternative ways of activating Wingless, one is more robust than the other. Our method provides a more complete measure of robustness to parameter variation. As a general modeling strategy, our approach is an interesting alternative to Boolean representation of biochemical networks