1,270 research outputs found

    Review on possible gravitational anomalies

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    This is an updated introductory review of 2 possible gravitational anomalies that has attracted part of the Scientific community: the Allais effect that occur during solar eclipses, and the Pioneer 10 spacecraft anomaly, experimented also by Pioneer 11 and Ulysses spacecrafts. It seems that, to date, no satisfactory conventional explanation exist to these phenomena, and this suggests that possible new physics will be needed to account for them. The main purpose of this review is to announce 3 other new measurements that will be carried on during the 2005 solar eclipses in Panama and Colombia (Apr. 8) and in Portugal (Oct.15).Comment: Published in 'Journal of Physics: Conferences Series of the American Institute of Physics'. Contribution for the VI Mexican School on Gravitation and Mathematical Physics "Approaches to Quantum Gravity" (Playa del Carmen, Quintana Roo, Mexico, Nov. 21-27, 2004). Updates to this information will be posted in http://www.lsc-group.phys.uwm.edu/~xavier.amador/anomalies.htm

    Genome-by-Trauma Exposure Interactions in Adults With Depression in the UK Biobank

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    IMPORTANCE: Self-reported trauma exposure has consistently been found to be a risk factor for major depressive disorder (MDD), and several studies have reported interactions with genetic liability. To date, most studies have examined gene-environment interactions with trauma exposure using genome-wide variants (single-nucleotide variations [SNVs]) or polygenic scores, both typically capturing less than 3% of phenotypic risk variance. OBJECTIVE: To reexamine genome-by-trauma interaction associations using genetic measures using all available genotyped data and thus, maximizing accounted variance. DESIGN, SETTING, AND PARTICIPANTS: The UK Biobank study was conducted from April 2007 to May 1, 2016 (follow-up mental health questionnaire). The current study used available cross-sectional genomic and trauma exposure data from UK Biobank. Participants who completed the mental health questionnaire and had available genetic, trauma experience, depressive symptoms, and/or neuroticism information were included. Data were analyzed from April 1 to August 30, 2021. EXPOSURES: Trauma and genome-by-trauma exposure interactions. MAIN OUTCOMES AND MEASURES: Measures of self-reported depression, neuroticism, and trauma exposure with whole-genome SNV data are available from the UK Biobank study. Here, a mixed-model statistical approach using genetic, trauma exposure, and genome-by-trauma exposure interaction similarity matrices was used to explore sources of variation in depression and neuroticism. RESULTS: Analyses were conducted on 148 129 participants (mean [SD] age, 56 [7] years) of which 76 995 were female (52.0%). The study approach estimated the heritability (SE) of MDD to be approximately 0.160 (0.016). Subtypes of self-reported trauma exposure (catastrophic, adult, childhood, and full trauma) accounted for a significant proportion of the variance of MDD, with heritability (SE) ranging from 0.056 (0.013) to 0.176 (0.025). The proportion of MDD risk variance accounted for by significant genome-by-trauma interaction revealed estimates (SD) ranging from 0.074 (0.006) to 0.201 (0.009). Results from sex-specific analyses found genome-by-trauma interaction variance estimates approximately 5-fold greater for MDD in male participants (0.441 [0.018]) than in female participants (0.086 [0.009]). CONCLUSIONS AND RELEVANCE: This cross-sectional study used an approach combining all genome-wide SNV data when exploring genome-by-trauma interactions in individuals with MDD; findings suggest that such interactions were associated with depression manifestation. Genome-by-trauma interaction accounts for greater trait variance in male individuals, which points to potential differences in depression etiology between the sexes. The methodology used in this study can be extrapolated to other environmental factors to identify modifiable risk environments and at-risk groups to target with interventions

    DynaMo - Software for vibration based structural health monitoring

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    This paper presents an innovative software for continuous dynamic monitoring of civil infrastructures. The followed approach is based in the continuous on-line automatic identification of the structure modal parameters, using its response under operation and adopting state-of-the-art identification algorithms. Therefore, the monitoring software, called DynaMo, includes routines for data and results management, algorithms for operational modal analysis, statistical tools for elimination of environmental and operational factors on the identified modal parameters and also statistical tools for automatic identification of abnormal frequency values that might be associated with the occurrence of damage. The utility and efficiency of DynaMo is illustrated with an application on a large span concrete arch bridge that is being monitored since 2007. © 2012 Taylor & Francis Group

    Sequestered Dark Matter

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    We show that hidden-sector dark matter is a generic feature of the type IIB string theory landscape and that its lifetime may allow for a discovery through the observation of very energetic gamma-rays produced in the decay. Throats or, equivalently, conformally sequestered hidden sectors are common in flux compactifications and the energy deposited in these sectors can be calculated if the reheating temperature of the standard model sector is known. Assuming that throats with various warp factors are available in the compact manifold, we determine which throats maximize the late-time abundance of sequestered dark matter. For such throats, this abundance agrees with cosmological data if the standard model reheating temperature was 10^10 - 10^11 GeV. In two distinct scenarios, the mass of dark matter particles, i.e. the IR scale of the throat, is either around 10^5 GeV or around 10^10 GeV. The lifetime and the decay channels of our dark matter candidates depend crucially on the fact that the Klebanov-Strassler throat is supersymmetric. Furthermore, the details of supersymmetry breaking both in the throat and in the visible sector play an essential role. We identify a number of scenarios where this type of dark matter can be discovered via gamma-ray observations.Comment: 36 pages, 3 figures; v2: references added, v3: introduction extended and typos correcte

    Glueballs, symmetry breaking and axionic strings in non-supersymmetric deformations of the Klebanov-Strassler background

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    We obtain an analytic solution for an axionic non-supersymmetric deformation of the warped deformed conifold. This allows us to study D-strings in the infrared limit of non-supersymmetric deformations of the Klebanov-Strassler background. They are interpreted as axionic strings in the dual field theory. Following the arguments of [hep-th/0405282], the axion is a massless pseudo-scalar glueball which is present in the supergravity fluctuation spectrum and it is interpreted as the Goldstone boson of the spontaneously broken U(1) baryon number symmetry, being the gauge theory on the baryonic branch. Besides, we briefly discuss about the Pando Zayas-Tseytlin solution where the SU(2) \times SU(2) global symmetry is spontaneously broken. This background has been conjectured to be on the mesonic branch of the gauge theory.Comment: 30 pages; V2: minor corrections; V3: section 3 corrected and misprints corrected to match version published in JHE

    S=1/2S=1/2 Chain-Boundary Excitations in the Haldane Phase of 1D S=1S=1 Systems

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    The s=1/2s=1/2 chain-boundary excitations occurring in the Haldane phaseof s=1s=1 antiferromagnetic spin chains are investigated. The bilinear-biquadratic hamiltonian is used to study these excitations as a function of the strength of the biquadratic term, β\beta, between 1β1-1\le\beta\le1. At the AKLT point, β=1/3\beta=-1/3, we show explicitly that these excitations are localized at the boundaries of the chain on a length scale equal to the correlation length ξ=1/ln3\xi=1/\ln 3, and that the on-site magnetization for the first site is =2/3=2/3. Applying the density matrixrenormalization group we show that the chain-boundaryexcitations remain localized at the boundaries for 1β1-1\le\beta\le1. As the two critical points β=±1\beta=\pm1 are approached the size of the s=1/2s=1/2 objects diverges and their amplitude vanishes.Comment: 4 Pages, 4 eps figures. Uses RevTeX 3.0. Submitted to PR

    Bacterias promotoras de crecimiento de plantas autóctonas y su efecto en "Prosopis chilensis" (Molina) Stunz

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    Today in Mexico are being deforestated the species Prosopis spp. for use as firewood and charcoal, in various arid regions of the country. For its production a synthetic fertilizer is used, thus there is an increase in soil, groundwater and aquifers salinity. This research was conducted in Santa Ana, Sonora, Mexico in 2006. Were isolated and purified microorganisms associated with the root system of Prosopis glandulosa growing in craters of the volcanic area from El Pinacate and Gran Desierto de Altar, Sonora Biosphere Reserve. The plant growth-promoting bacteria present the peculiarity of fixing atmospheric nitrogen; the effect of the isolates on germination and seedling development in P. chilensiswas measured. 19 colonies were isolated; of them, only one bacterial colony showed high acetylene reduction activity and ability to solubilize phosphate, was identified as Bacillus amyloliquefaciens. Our results suggest that B. amyloliquefaciens, has a particular affinity to grow from 0 to 0.75M of NaCl and develops at temperatures of 30 to 50 °C. The effects of inoculation of B. amyloliquefaciens, along with A. halopraeferens, showed favorable results in the increase of germination and seedling development of P. chilensis. This is the first report of B. amyloliquefaciensas a plant growth promoting bacteria associated with P. glandulosa.En la actualidad se está deforestando en México la especie de Prosopis spp. para utilizarse como leña y carbón, en diferentes zonas áridas de nuestro país. Para su producción se utiliza fertilizante sintético, con ello hay un incremento de salinidad del suelo, subsuelo y mantos acuíferos. La presente investigación se realizó en Santa Ana, Sonora, México en 2006. Se aislaron y purificaron microorganismos asociados al sistema radicular de Prosopis glandulosa que se desarrolla en cráteres de la zona volcánica de la reserva de la biosfera El Pinacate y Gran Desierto de Altar Sonora. Las bacterias promotoras de crecimiento de plantas presentan la peculiaridad de fijar el nitrógeno atmosférico; se midió el efecto de las cepas aisladas en germinación y en el desarrollo en plántulas de P. chilensis. Fueron aisladas 19 colonias; de ellas, solamente una colonia bacteriana mostró alta actividad de reducción de acetileno y capacidad de solubilizar fosfatos, se identificó como Bacillus amyloliquefaciens. Nuestros resultados sugieren que B. amyloliquefaciens, presenta una afinidad particular para crecer de 0 a 0.75 M de NaCl y desarrollarse en temperaturas de 30 a 50 °C. Los efectos de la inoculación de B. amyloliquefaciens, conjuntamente con A. halopraeferens, mostraron reultados favorables en el incremento de la germinación y el desarrollo de plántulas de P. chilensis. Éste es el primer reporte de B. amyloliquefaciens como bacteria promora de crecimiento de plantas asociada a P. glandulosa
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