3,577 research outputs found
Multi-variate joint PDF for non-Gaussianities: exact formulation and generic approximations
We provide an exact expression for the multi-variate joint probability
distribution function of non-Gaussian fields primordially arising from local
transformations of a Gaussian field. This kind of non-Gaussianity is generated
in many models of inflation. We apply our expression to the non- Gaussianity
estimation from Cosmic Microwave Background maps and the halo mass function
where we obtain analytical expressions. We also provide analytic approximations
and their range of validity. For the Cosmic Microwave Background we give a fast
way to compute the PDF which is valid up to 7{\sigma} for fNL values (both true
and sampled) not ruled out by current observations, which consists of
expressing the PDF as a combination of bispectrum and trispectrum of the
temperature maps. The resulting expression is valid for any kind of
non-Gaussianity and is not limited to the local type. The above results may
serve as the basis for a fully Bayesian analysis of the non-Gaussianity
parameter.Comment: Matches accepted verion to JCAP; conclusions unchaged, extra
references adde
SEARCHING for NEW YELLOW SYMBIOTIC STARS: POSITIVE IDENTIFICATION of StHα63
Yellow symbiotic stars are useful targets for probing whether mass transfer has happened in their binary systems. However, the number of known yellow symbiotic stars is very scarce. We report spectroscopic observations of five candidate yellow symbiotic stars that were selected by their positions in the 2MASS (J - H) versus (H - K) diagram and which were included in some emission-line catalogs. Among the five candidates, only StHα63 is identified as a new yellow symbiotic star because of its spectrum and its position in the [TiO]-[TiO] diagram, which indicates a K4-K6 spectral type. In addition, the derived electron density (∼10 cm) and several emission-line intensity ratios provide further support for that classification. The other four candidates are rejected as symbiotic stars because three of them actually do not show emission lines and the fourth one only Balmer emission lines. We also found that the WISE W3-W4 index clearly separates normal K-giants from yellow symbiotic stars and therefore can be used as an additional tool for selecting candidate yellow symbiotic stars.L.F.M. acknowledges partial support by grants AYA2011-30228-C03.01 and AYA2014-57369-C3-3-P of the Spanish MINECO, both co-funded by FEDER funds.Peer Reviewe
A task-based evaluation methodology for visual representation of dynamic networks
Current evaluation approaches for visualization strategies of dynamic networks are focused on maintaining the mental map ofthe network over the time or keeping a certain shape to make iteasy to navigate, however the available tools for analyzing temporal network have not been evaluated in terms of how easy to usethey are to perform exploratory data analysis tasks with dynamicnetworks. In this work we present an evaluation methodologythat guides the usability assessment of software tools used to analyze dynamic networks by using the standard ISO 9241-11. Thismethodology has been applied successfully with two popularopen source tools used to analyze temporal networks.ITESO, A.C
On Mass-Spring System Implementation in Cluster-Based MANETs for Natural Disaster Applications
Communication after natural disasters is paramount.Disasters such as earthquakes, hurricanes and tsunamis leavethe affected area reachable only to wireless devices. In suchconditions, Mobile Ad-hoc Networks (MANETs) play a criticalrole. The issue of MANETs communication backbone can beaddressed by self-organized cluster-based algorithms. The vir-tual backbone will maintain an efficient communication on theMANET, adapting to the dynamic topology changes thanks toits self-organized nature. Nevertheless, they do not take intoaccount the node’s mobility. If a node moves away from itsneighboring nodes, connectivity will be lost and thus, networksegmentation will occur. Therefore, it is fundamental to maintainthe connectivity and the communication between nodes whileexploring the area. In this paper, we propose the applicationof a mass-spring system on the Energy-Efficient Self-OrganizedAlgorithm (EESOA) for Disaster Area applications. Results willshow that our proposal performs best when deployment ofMANET’s nodes is dense while maintaining a connected network.ITESO, A.C
Suicide ideation, planning, and attempts: the case of the Latinx LGB youth
Background: Guided by an ecological systems theory (EST) framework, the purpose of the present study was to investigate how multiple micro, mezzo, and macro factors influence the suicidality continuum from suicidal ideation to suicide attempt among Latinx LGB (lesbian, gay, and bisexual) youth living in the United States.
Methods: Data for this cross sectional-study included 451 participants who self-identified as Latinx LGB on the 2017-National Youth Risk Behavioral Survey. The analysis explored micro, mezzo, and macro-level factors’ association with three suicidality outcomes (ideation, planning, and attempt) at the bivariate and multivariate level. Since the outcome variables were dichotomized, univariate logistic regressions and backward elimination logistic regressions were used. Results: The most commonly reported suicidal behavior was ideation (n = 173; 40%), followed by planning (n = 150; 34%), and then attempt (n = 64; 21%). Findings from the backward elimination logistic regression on suicidal ideation suggest the best set of independent variables are being bullied at school (odds ratio [OR] = 2.81; CI: 1.61–4.89), experiencing sexual assault (OR = 2.32; CI: 1.32–4.07), experiencing depressive symptoms (OR = 1.99; CI: 1.07– 3.69), being cannabis use (OR = 1.76; CI: 1.08–2.89), and being female (OR = 1.72; CI: 1.01–2.93). For suicide planning the model suggested, experiencing depressive symptoms (OR = 3.21; CI: 1.74–5.91), cannabis use (OR = 2.46; CI: 1.49–4.07), being bullied at school (OR = 2.04; CI: 1.17–3.58), and experiencing sexual assault (OR = 1.88; CI: 1.07–3.31) exhibited the strongest relationships. Suicide attempt was significantly associated with cannabis use (OR = 3.12; CI: 1.60–6.08), experiencing depression (OR= 2.89; CI: 1.30–6.43), experiencing sexual assault (OR = 2.77; CI: 1.34–5.71), and being bullied at school (OR = 2.34; CI: 1.12–4.91).
Conclusion: Given the findings of this study, it is essential that tailored suicide prevention efforts be established that uniquely address the intersections of race/ethnicity and sexual orientation and how this intersection influences micro, mezzo, and macro factors associated with suicide ideation, planning, and attempt among Latinx LGB adolescents
The ArcB Leucine Zipper Domain Is Required for Proper ArcB Signaling
The Arc two-component system modulates the expression of numerous genes in response to respiratory growth conditions. This system comprises ArcA as the response regulator and ArcB as the sensor kinase. ArcB is a tripartite histidine kinase whose activity is regulated by the oxidation of two cytosol-located redox-active cysteine residues that participate in intermolecular disulfide bond formation. Here, we report that the ArcB protein segment covering residues 70–121, fulfills the molecular characteristics of a leucine zipper containing coiled coil structure. Also, mutational analyses of this segment reveal three different phenotypical effects to be distributed along the coiled coil structure of ArcB, demonstrating that this motif is essential for proper ArcB signaling
Insulin Receptor Substrate-1 Expression Is Increased in Circulating Leukocytes of Patients with Acute Coronary Syndrome
The mechanisms underlying the increased risk of cardiovascular disease associated with diabetes mellitus (DM) are not fully defined. Insulin resistance in human metabolic syndrome patients is associated with decreased expression of the insulin receptor substrate-2- (Irs2-) AKT2 axis in mononuclear leukocytes (MLs). Moreover, acute coronary syndrome (ACS) has been linked through genome-wide association studies to the 2q36-q37.3 locus, which contains the Irs1 gene. Here, we investigated the expression of insulin-signaling pathway genes in MLs from patients with DM, ACS, and ACS plus DM. Quantitative real-time PCR expression studies showed no differences in the mRNA levels of Irs2, Akt2, and Akt1 among all patients. However, Irs1 mRNA expression was significantly increased in patients with ACS—diabetics and nondiabetics—compared with diabetic patients without ACS (P < .02 and P < .005, resp.). The present study reveals for the first time an association between increased Irs1 mRNA levels in MLs of patients with ACS which is not related to DM
Proteomics - A Powerful Tool to Deepen the Molecular Mechanisms of Aortic Stenosis Disease
We thank the grants from the Instituto de Salud Carlos III (FIS PI070537), Fondo de Investigación Sanitaria de Castilla la Mancha (FISCAM, PI2008/08), Fondo de Investigación Sanitaria de Castilla la Mancha (FISCAM PI2008/28) and Redes Temáticas de Investigación Cooperativa, FONDOS FEDER (RD06/0014/1015)Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEpu
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