512 research outputs found
5d quivers and their AdS(6) duals
We consider an infinite class of 5d supersymmetric gauge theories involving
products of symplectic and unitary groups that arise from D4-branes at orbifold
singularities in Type I' string theory. The theories are argued to be dual to
warped AdS(6)x S4/Zn backgrounds in massive Type IIA supergravity. In
particular, this demonstrates the existence of supersymmetric 5d fixed points
of quiver type. We analyze the spectrum of gauge fields and charged states in
the supergravity dual, and find a precise agreement with the symmetries and
charged operators in the quiver theories. We also comment on other brane
objects in the supergravity dual and their interpretation in the field
theories.Comment: 29 pages, 15 figure
CD209 in inflammatory bowel disease: a case-control study in the Spanish population
<p>Abstract</p> <p>Background</p> <p>The etiology of Ulcerative Colitis (UC) and Crohn's Disease (CD), considered together as Inflammatory Bowel Diseases (IBD), involves environmental and genetic factors. Although some genes are already known, the genetics underlying these diseases is complex and new candidates are continuously emerging. The <it>CD209 </it>gene is located in a region linked previously to IBD and a <it>CD209 </it>functional polymorphism (rs4804803) has been associated to other inflammatory conditions. Our aim was to study the potential involvement of this <it>CD209 </it>variant in IBD susceptibility.</p> <p>Methods</p> <p>We performed a case-control study with 515 CD patients, 497 UC patients and 731 healthy controls, all of them white Spaniards. Samples were typed for the <it>CD209 </it>single nucleotide polymorphism (SNP) rs4804803 by TaqMan technology. Frequency comparisons were performed using χ<sup>2 </sup>tests.</p> <p>Results</p> <p>No association between <it>CD209 </it>and UC or CD was observed initially. However, stratification of UC patients by <it>HLA-DR3 </it>status, a strong protective allele, showed that carriage of the <it>CD209</it>_G allele could increase susceptibility in the subgroup of <it>HLA-DR3</it>-positive individuals (p = 0.03 OR = 1.77 95% CI 1.04–3.02, <it>vs. </it>controls).</p> <p>Conclusion</p> <p>A functional variant in the <it>CD209 </it>gene, rs4804803, does not seem to be influencing Crohn's disease susceptibility. However, it could be involved in the etiology or pathology of Ulcerative Colitis in <it>HLA-DR3</it>-positive individuals but further studies are necessary.</p
An algorithm to reduce the occupational space in gender segregation studies
This paper presents an algorithm based on the bootstrap to select an admissible aggregation level, that is, the minimum number of occupational categories that yield a gender segregation value not significantly smaller than that obtained from the large number of occupational categories usually available in any data set. The approach is illustrated using labour force survey data for Spain for the comparison of gender segregation in 1977 and 1992, as well as 1994 and 2000. To measure gender segregation, an additively decomposable segregation index based on the entropy concept is used. Despite a substantial simplification in the size of the occupation space, the decrease in the segregation index is very small and not significant, regardless of the year. Consequently, intertemporal changes in gender segregation can be studied using a greatly reduced classification of occupations that permits an easier interpretation of results.Publicad
First Colombian Multicentric Newborn Screening for Congenital Toxoplasmosis
Congenital toxoplasmosis can result in permanent sequel as blindness or neurological damage in children and it seems to be more severe in South America than in other continents. There is a lack of information about this frequency in Colombia, where no control program is established, although it is a recognized cause of potentially preventable congenital blindness. We propose the first Colombian multicentric study to determine the frequency and impact of congenital toxoplasmosis. More than 15,000 newborns in seven cities were studied. Newborns were tested at birth by doing a cord blood test for toxoplasmosis. Additionally, children from mothers with history of toxoplasmosis acquired during pregnancy were recalled for a follow-up. The program identified fifteen children otherwise undiagnosed; three of these children died as consequence of congenital toxoplasmosis. The frequency of the congenital infection varied significantly between cities, being higher in Armenia and Florencia, intermediate in Bogota, Bucaramanga and Barranquilla and very low in western cities such as Cucuta and Riohacha. For the first time a significant correlation was found between mean rainfall at the city and the incidence of this congenital infection
A change in the optical polarization associated with a gamma-ray flare in the blazar 3C 279
It is widely accepted that strong and variable radiation detected over all
accessible energy bands in a number of active galaxies arises from a
relativistic, Doppler-boosted jet pointing close to our line of sight. The size
of the emitting zone and the location of this region relative to the central
supermassive black hole are, however, poorly known, with estimates ranging from
light-hours to a light-year or more. Here we report the coincidence of a
gamma-ray flare with a dramatic change of optical polarization angle. This
provides evidence for co-spatiality of optical and gamma-ray emission regions
and indicates a highly ordered jet magnetic field. The results also require a
non-axisymmetric structure of the emission zone, implying a curved trajectory
for the emitting material within the jet, with the dissipation region located
at a considerable distance from the black hole, at about 10^5 gravitational
radii.Comment: Published in Nature issued on 18 February 2010. Corresponding
authors: Masaaki Hayashida and Greg Madejsk
Systems and technologies for objective evaluation of technical skills in laparoscopic surgery
Minimally invasive surgery is a highly demanding surgical approach regarding technical requirements for the surgeon, who must be trained in order to perform a safe surgical intervention. Traditional surgical education in minimally invasive surgery is commonly based on subjective criteria to quantify and evaluate surgical abilities, which could be potentially unsafe for the patient. Authors, surgeons and associations are increasingly demanding the development of more objective assessment tools that can accredit surgeons as technically competent. This paper describes the state of the art in objective assessment methods of surgical skills. It gives an overview on assessment systems based on structured checklists and rating scales, surgical simulators, and instrument motion analysis. As a future work, an objective and automatic assessment method of surgical skills should be standardized as a means towards proficiency-based curricula for training in laparoscopic surgery and its certification
Long-COVID cognitive impairments and reproductive hormone deficits in men may stem from GnRH neuronal death
BACKGROUND: We have recently demonstrated a causal link between loss of gonadotropin-releasing hormone (GnRH), the master molecule regulating reproduction, and cognitive deficits during pathological aging, including Down syndrome and Alzheimer's disease. Olfactory and cognitive alterations, which persist in some COVID-19 patients, and long-term hypotestosteronaemia in SARS-CoV-2-infected men are also reminiscent of the consequences of deficient GnRH, suggesting that GnRH system neuroinvasion could underlie certain post-COVID symptoms and thus lead to accelerated or exacerbated cognitive decline. METHODS: We explored the hormonal profile of COVID-19 patients and targets of SARS-CoV-2 infection in post-mortem patient brains and human fetal tissue. FINDINGS: We found that persistent hypotestosteronaemia in some men could indeed be of hypothalamic origin, favouring post-COVID cognitive or neurological symptoms, and that changes in testosterone levels and body weight over time were inversely correlated. Infection of olfactory sensory neurons and multifunctional hypothalamic glia called tanycytes highlighted at least two viable neuroinvasion routes. Furthermore, GnRH neurons themselves were dying in all patient brains studied, dramatically reducing GnRH expression. Human fetal olfactory and vomeronasal epithelia, from which GnRH neurons arise, and fetal GnRH neurons also appeared susceptible to infection. INTERPRETATION: Putative GnRH neuron and tanycyte dysfunction following SARS-CoV-2 neuroinvasion could be responsible for serious reproductive, metabolic, and mental health consequences in long-COVID and lead to an increased risk of neurodevelopmental and neurodegenerative pathologies over time in all age groups. FUNDING: European Research Council (ERC) grant agreements No 810331, No 725149, No 804236, the European Union Horizon 2020 research and innovation program No 847941, the Fondation pour la Recherche Médicale (FRM) and the Agence Nationale de la Recherche en Santé (ANRS) No ECTZ200878 Long Covid 2021 ANRS0167 SIGNAL, Agence Nationale de la recherche (ANR) grant agreements No ANR-19-CE16-0021-02, No ANR-11-LABEX-0009, No. ANR-10-LABEX-0046, No. ANR-16-IDEX-0004, Inserm Cross-Cutting Scientific Program HuDeCA, the CHU Lille Bonus H, the UK Medical Research Council (MRC) and National Institute of Health and care Research (NIHR)
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