269 research outputs found
Instanton effects and linear-chiral duality
We discuss duality between the linear and chiral dilaton formulations, in the
presence of super-Yang-Mills instanton corrections to the effective action. In
contrast to previous work on the subject, our approach appeals directly to
explicit instanton calculations and does not rely on the introduction of an
auxiliary Veneziano-Yankielowicz superfield. We discuss duality in the case of
an axion that has a periodic scalar potential, and find that the bosonic fields
of the dual linear multiplet have a modified interpretation. We note that
symmetries of the axion potential manifest themselves as symmetries of the
equations of motion for the linear multiplet. We also make some brief remarks
regarding dilaton stabilization. We point out that corrections recently studied
by Dijkgraaf and Vafa can be used to stabilize the axion in the case of a
single super-Yang-Mills condensate.Comment: 1+18 pages, 1 figure, comments and references adde
A Diverse Array of Fluvial Depositional Systems in Arabia Terra: Evidence for midâNoachian to Early Hesperian Rivers on Mars
Branching to sinuous ridges systems, 100s of kilometers in length and comprising layered strata, are present across much of Arabia Terra, Mars. These ridges are interpreted as depositional fluvial channels, now preserved as inverted topography. Here we use high resolution image and topographic datasets to investigate the morphology of these depositional systems and show key examples of their relationships to associated fluvial landforms. The inverted channel systems likely comprise indurated conglomerate, sandstone, and mudstone bodies, which form a multiâstorey channel stratigraphy. The channel systems intersect local basins and indurated sedimentary mounds, that we interpret as paleolake deposits. Some inverted channels are located within erosional valley networks, which have regional and local catchments. Inverted channels are typically found in downslope sections of valley networks, sometimes at the margins of basins, and numerous different transition morphologies are observed. These relationships indicate a complex history of erosion and deposition, possibly controlled by changes in water or sediment flux, or base level variation. Other inverted channel systems have no clear preserved catchment; likely lost due to regional resurfacing of upland areas. Sediment may have been transported through Arabia Terra towards the dichotomy and stored in local and regionalâscale basins. Regional stratigraphic relations suggest these systems were active between the midâNoachian and early Hesperian. The morphology of these systems is supportive of an early Mars climate which was characterized by prolonged precipitation and runoff
Aram Dorsum: an extensive mid-Noachian age fluvial depositional system in Arabia Terra, Mars
A major debate in Mars science is the nature of the early Mars climate, and the availability of precipitation and runoff. Observations of relict erosional valley networks have been proposed as evidence for extensive surface runâoff around the NoachianâHesperian boundary. However, these valley networks only provide a timeâintegrated record of landscape evolution and thus the timing, relative timescales and intensity of aqueous activity required to erode the valleys remain unknown. Here, we investigate an ancient fluvial sedimentary system in western Arabia Terra, now preserved in positive relief. This ridge, âAram Dorsumâ, is flatâtopped, branching, ~ 85 km long, and particularly wellâpreserved. We show that Aram Dorsum was an aggradational alluvial system and that the existing ridge was once a large river channelâbelt set in extensive flood plains, many of which are still preserved. Smaller, palaeochannelâbelts feed the main system; their setting and network pattern suggest a distributed source of water. The alluvial succession is up to 60 m thick, suggesting a formation time of 105 to 107 years by analogy to Earth. Our observations are consistent with Aram Dorsum having formed by longâlived flows of water, sourced both locally, and regionally as part of a wider alluvial system in Arabia Terra. This suggests frequent or seasonal precipitation as the source of water. Correlating our observations with previous regionalâscale mapping shows that Aram Dorsum formed in the midâNoachian, making it one of the oldest fluvial systems described on Mars and indicating climatic conditions that sustained surface river flows on early Mars
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
Sensibilidad ĂŠtica, conocimientos y su relaciĂłn con el consumo del alcohol en estudiantes universitarios
Introduction: care is an element influenced by multiple factors, among them, the axiological approach and ethical sensitivity, acting as a determinant in the quality of care provided to the patient. On the other hand, health problems related to alcohol consumption are becoming more and more frequent, giving way to the creation of moral dilemmas, in which the question arises whether an individual who affects his human responses by choice deserves the same level of care as those without control over his disease. Objective: to determine the relationship between ethical sensitivity, knowledge and alcohol consumption in university students. Methods: quantitative, descriptive, correlational, prospective and cross-sectional study, applying the Ethical Sensitivity, NEADA and AUDIT instruments to a group of nursing students belonging to a public university and selected by stratified probabilistic sampling. Results and discussion: ethical sensitivity scored at medium levels (52.3%), knowledge about alcohol was medium (81.7%) and consumption was characterized as risky (58.0%). Conclusions: The aim is for students to promote ethical and healthy behaviors through participation in social groups and workshops on didactic techniques that address addiction issues.IntroducciĂłn: el cuidado es un elemento influenciado por mĂşltiples factores, entre ellos, el enfoque axiolĂłgico y sensibilidad ĂŠtica, fungiendo como un determinante en la calidad de la atenciĂłn que se brinda al paciente. Por otro lado, los problemas de salud relacionados con el consumo de alcohol son cada vez mĂĄs mĂĄs frecuentes, dando paso a la creaciĂłn de dilemas morales, en ellos plantea si un individuo que afecta sus respuestas humas por elecciĂłn propia merece el mismo nivel de atenciĂłn que aquellos sin control sobre su enfermedad. Objetivo: determinar la relaciĂłn que existe en sensibilidad ĂŠtica, conocimientos y consumo de alcohol en estudiantes universitarios. Material y mĂŠtodos: estudio cuantitativo, descriptivo, correlacional, prospectivo y transversal, aplicando los instrumentos Sensibilidad ĂŠtica, NEADA y AUDIT a un grupo de estudiantes de EnfermerĂa pertenecientes a Universidad pĂşblica y seleccionados mediante un muestreo probabilĂstico estratificado. Resultados y discusiĂłn: la sensibilidad ĂŠtica puntuĂł en niveles medios (52.3%), el conocimiento sobre el alcohol en medio (81.7%) y el consumo se caracterizĂł como riesgoso (58.0%). Conclusiones: se busca que el estudiante en promueva conductas ĂŠticas y saludables mediante la participaciĂłn en grupos sociales y talleres sobre tĂŠcnicas didĂĄcticas que aborden de temas de adicciones
Twenty-eight genetic loci associated with ST-T-wave amplitudes of the electrocardiogram
The ST-segment and adjacent T-wave (ST-T wave) amplitudes of the electrocardiogram are quantitative characteristics of cardiac repolarization. Repolarization abnormalities have been linked to ventricular arrhythmias and sudden cardiac death. We performed the first genome-wide association meta-analysis of ST-T-wave amplitudes in up to 37 977 individuals identifying 71 robust genotype-phenotype associations clustered within 28 independent loci. Fifty-four genes were prioritized as candidates underlying the phenotypes, including genes with established roles in the cardiac repolarization phase (SCN5A/SCN10A, KCND3, KCNB1, NOS1AP and HEY2) and others with as yet undefined cardiac function. These associations may provide insights in the spatiotemporal contribution of genetic variation influencing cardiac repolarization and provide novel leads for future functional follow-up
Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases
Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r =-0.62, P = 5.30 Ă 10-5) but not between CCT and primary open-angle glaucoma (r =-0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation
Alignment of the CMS silicon tracker during commissioning with cosmic rays
This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe CMS silicon tracker, consisting of 1440 silicon pixel and 15 148 silicon strip detector modules, has been aligned using more than three million cosmic ray charged particles, with additional information from optical surveys. The positions of the modules were determined with respect to cosmic ray trajectories to an average precision of 3â4 microns RMS in the barrel and 3â14 microns RMS in the endcap in the most sensitive coordinate. The results have been validated by several studies, including laser beam cross-checks, track fit self-consistency, track residuals in overlapping module regions, and track parameter resolution, and are compared with predictions obtained from simulation. Correlated systematic effects have been investigated. The track parameter resolutions obtained with this alignment are close to the design performance.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ,
and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS
(Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia);
Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG,
and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT,
SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
Commissioning and performance of the CMS pixel tracker with cosmic ray muons
This is the Pre-print version of the Article. The official published verion of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe pixel detector of the Compact Muon Solenoid experiment consists of three barrel layers and two disks for each endcap. The detector was installed in summer 2008, commissioned with charge injections, and operated in the 3.8 T magnetic field during cosmic ray data taking. This paper reports on the first running experience and presents results on the pixel tracker performance, which are found to be in line with the design specifications of this detector. The transverse impact parameter resolution measured in a sample of high momentum muons is 18 microns.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ,
and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia);
Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG,
and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT,
SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)
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