2,349 research outputs found
Rational points in the moduli space of genus two
We build a database of genus 2 curves defined over which contains
all curves with minimal absolute height , all curves with moduli
height , and all curves with extra automorphisms in
standard form defined over with height .
For each isomorphism class in the database, an equation over its minimal field
of definition is provided, the automorphism group of the curve, Clebsch and
Igusa invariants. The distribution of rational points in the moduli space
for which the field of moduli is a field of definition is
discussed and some open problems are presented
Household decision-making about delivery in health facilities: evidence from Tanzania.
This study investigated how partners' perceptions of the healthcare system influence decisions about delivery-location in low-resource settings. A multistage population-representative sample was used in Kasulu district, Tanzania, to identify women who had given birth in the last five years and their partners. Of 826 couples in analysis, 506 (61.3%) of the women delivered in the home. In multivariate analysis, factors associated with delivery in a health facility were agreement of partners on the importance of delivering in a health facility and agreement that skills of doctors are better than those of traditional birth attendants. When partners disagreed, the opinion of the woman was more influential in determining delivery-location. Agreement of partners regarding perceptions about the healthcare system appeared to be an important driver of decisions about delivery-location. These findings suggest that both partners should be included in the decision-making process regarding delivery to raise rates of delivery at facility
The virtual observatory service TheoSSA: Establishing a database of synthetic stellar flux standards. II. NLTE spectral analysis of the OB-type subdwarf Feige 110
In the framework of the Virtual Observatory (VO), the German Astrophysical
Virtual Observatory (GAVO) developed the registered service TheoSSA
(Theoretical Stellar Spectra Access). It provides easy access to stellar
spectral energy distributions (SEDs) and is intended to ingest SEDs calculated
by any model-atmosphere code, generally for all effective temperature, surface
gravities, and elemental compositions. We will establish a database of SEDs of
flux standards that are easily accessible via TheoSSA's web interface.
The OB-type subdwarf Feige 110 is a standard star for flux calibration.
State-of-the-art non-local thermodynamic equilibrium (NLTE) stellar-atmosphere
models that consider opacities of species up to trans-iron elements will be
used to provide a reliable synthetic spectrum to compare with observations.
In case of Feige 110, we demonstrate that the model reproduces not only its
overall continuum shape from the far-ultraviolet (FUV) to the optical
wavelength range but also the numerous metal lines exhibited in its FUV
spectrum.
We present a state-of-the-art spectral analysis of Feige 110. We determined
, and
the abundances of He, N, P, S, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, and Ge. Ti, V,
Mn, Co, Zn, and Ge were identified for the first time in this star. Upper
abundance limits were derived for C, O, Si, Ca, and Sc.
The TheoSSA database of theoretical SEDs of stellar flux standards guarantees
that the flux calibration of astronomical data and cross-calibration between
different instruments can be based on models and SEDs calculated with
state-of-the-art model-atmosphere codes.Comment: 19 pages, 7 figure
New Wave of Component Reuse with Spring Framework - AP Case Study
The myth of component reuse has always been the âholy grailâ of software engineering. The motivation var-ies from less time, effort and money expenditure to higher system quality and reliability which is especially impor-tant in the domain of high energy physics and accelerator controls. Identified as an issue by D. McIlroy in 1968 [1], it has been generally addressed in many ways with vari-ous success rates. But only recently with the advent of fresh ideas like the Spring Framework with its powerful yet simple âInversion of Controlâ paradigm the solution to the problem has started to be surprisingly uncompli-cated. Gathered over years of experience this document explains best practices and lessons learned applied at CERN for the design of the operational software used to control the accelerator complex and focuses on features of the Spring Framework that render the component reuse achievable in practice. It also provides real life use cases of mission-critical control systems developed by the Ap-plication Section like the LHC Software Architecture (LSA), the Injector Control Architecture (InCA) or the Software Interlock System (SIS) that have built their own success mostly upon a stack of reusable software components
Metal abundances in PG1159 stars from Chandra and FUSE spectroscopy
We investigate FUSE spectra of three PG1159 stars and do not find any
evidence for iron lines. From a comparison with NLTE models we conclude a
deficiency of 1-1.5 dex. We speculate that iron was transformed into heavier
elements. A soft X-ray Chandra spectrum of the unique H- and He-deficient star
H1504+65 is analyzed. We find high neon and magnesium abundances and confirm
that H1504+65 is the bare core of either a C-O or a O-Ne-Mg white dwarf.Comment: To be published in: Proceedings 13th European Workshop on White
Dwarfs, NATO Science Series, 4 pages, 1 figur
Modeling of orographic precipitation events in South America to couple hydrological and atmospheric models; part 1: The simulation of rain with the Mesoscale Model GESIMA
Globalmodelle sind aufgrund ihres groben Gitters (60 x 60 km) nur unzureichend in der Lage kleinskalige Prozesse (orographische NiederschlagsverstÀrkung) in der AtmosphÀre aufzulösen. Mit Mesoskalenmodellen z.B. dem GESIMA (5 x 5 km) können deshalb die
physikalische Grundlagen der AtmosphĂ€re (Wolken- und Niederschlagsbildung) besser studiert und eine Kopplung mit hydrologischen Abflussmodellen erprobt werden. ZukĂŒnftig sieht dieses Projekt genau das vor, wobei der erste Teil, die Arbeit mit dem meteorologische Modell hier vorgestellt werden soll. Starkniederschlagserreignisse sind vielerorts auf der Welt mit charakteristischen Wetterlagen verbunden, die quasi ĂŒber Tage unverĂ€ndert ergiebigen Regen produzieren. Initialisiert mit den lokalen Vertikalprofilen aus Radiosondendaten, produzieren das prognostische
Mesoskalenmodell GESIMA und das diagnostische Niederschlagsberechungsverfahren (MAXRR) maximale Regenmengen vergleichbarer GröĂenordnung.Global models are insufficient to solve small scale atmospheric processes (e.g. orographic precipitation) due to their gross resolution (60 x 60 km). With mesoscale models e.g. the GESIMA (5 x 5 km), the physical fundamentals of the atmosphere (formation of precipitation
and clouds) can better be studied and a coupling with hydrological models be tested through. This project plans exactly, as a first step, the work with the cited meteorological model. Heavy rainfall events are connected with characteristic weather conditions in many places in the world which produce invariably rain quasi over days. Initialized with the local vertical profiles from radiosonde data, the prediction model GESIMA and the diagnostic model MAXRR produced rain quantities of comparable order of magnitude
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