204 research outputs found
Verification of Java Bytecode using Analysis and Transformation of Logic Programs
State of the art analyzers in the Logic Programming (LP) paradigm are
nowadays mature and sophisticated. They allow inferring a wide variety of
global properties including termination, bounds on resource consumption, etc.
The aim of this work is to automatically transfer the power of such analysis
tools for LP to the analysis and verification of Java bytecode (JVML). In order
to achieve our goal, we rely on well-known techniques for meta-programming and
program specialization. More precisely, we propose to partially evaluate a JVML
interpreter implemented in LP together with (an LP representation of) a JVML
program and then analyze the residual program. Interestingly, at least for the
examples we have studied, our approach produces very simple LP representations
of the original JVML programs. This can be seen as a decompilation from JVML to
high-level LP source. By reasoning about such residual programs, we can
automatically prove in the CiaoPP system some non-trivial properties of JVML
programs such as termination, run-time error freeness and infer bounds on its
resource consumption. We are not aware of any other system which is able to
verify such advanced properties of Java bytecode
Life history baseline of unexploited populations: The case of Beryx splendens from the Sierra Leone Rise
This study examines for the first time the biology of alfonsino (Beryx splendens) from three small seamounts of the Sierra Leone Rise (SLR), an unexploited and fragile ecosystem in the Atlantic, using data from an experimental survey carried out in 2001 by Spanish longliners. In general, the lack of rigorous baseline data limits the implementation of efficient management and conservation plans in fisheries strategies. Therefore, the main aim of present study was to provide baseline information on basic biological parameters of the alfonsino population associated with an unexploited ecosystem. A total of 17296 individuals of alfonsino were sampled from SLR. Alfonsino is gonochoric and presented an unbalanced sex ratio, there were significantly more females than males. Taking into account the results in stage of maturity of alfonsino and the gonadosomatic index values during studied period, we can conclude that at least one reproductive period in these seamounts was in the late spring and early summer. The spawning stage was attained at a minimum fork length of 23 and 25 cm for males and females, respectively. The size at which 50% of the population attains sexual maturity was approximately 28 and 27 cm for males and females, respectively. The stock structure of alfonsino showed a segregation of the size with the depth, as they increase in size they move into the deeper water.Versión del edito
The association of parental and offspring educational attainment with systolic blood pressure, fasting blood glucose and waist circumference in Latino adults
Objective: The objective of the study is to evaluate the association of intergenerational educational attainment with cardiovascular disease (CVD) risk factors among US Latinos. Methods: We used cross-sectional data from the Niños Lifestyle and Diabetes Study, an offspring cohort of middle-aged Mexican-Americans whose parents participated in the Sacramento Latino Study on Aging. We collected educational attainment, demographic and health behaviours and measured systolic blood pressure (SBP), fasting glucose and waist circumference. We evaluated the association of parental, offspring and a combined parent–offspring education variable with each CVD risk factor using multivariable regression. Results: Higher parental education was associated only with smaller offspring waist circumference. In contrast, higher offspring education was associated with lower SBP, fasting glucose and smaller waist circumference. Adjustment for parental health behaviours modestly attenuated these offspring associations, whereas adjustment for offspring health behaviours and income attenuated the associations of offspring education with offspring SBP and fasting glucose but not smaller waist circumference, even among offspring with low parental education. Conclusions: Higher offspring education is associated with lower levels of CVD risk factors in adulthood, despite intergenerational exposure to low parental education
Forecasting maize yield at field scale based on high-resolution satellite imagery
Estimating maize (Zea mays L.) yields at the field level is of great interest to farmers, service dealers, and policy-makers. The main objectives of this study were to: i) provide guidelines on data selection for building yield forecasting models using Sentinel-2 imagery; ii) compare different statistical techniques and vegetation indices (VIs) during model building; and iii) perform spatial and temporal validation to see if empirical models could be applied to other regions or when models' coefficients should be updated. Data analysis was divided into four steps: i) data acquisition and preparation; ii) selection of training data; iii) building of forecasting models; and iv) spatial and temporal validation. Analysis was performed using yield data collected from 19 maize fields located in Brazil (2016 and 2017) and in the United States (2016), and normalized vegetation indices (NDVI, green NDVI and red edge NDVI) derived from Sentinel-2. Main outcomes from this study were: i) data selection impacted yield forecast model and fields with narrow yield variability and/or with skewed data distribution should be avoided; ii) models considering spatial correlation of residuals outperformed Ordinary least squares (OLS) regression; iii) red edge NDVI was most frequently retained into the model compared with the other VIs; and iv) model prediction power was more sensitive to yield data frequency distribution than to the geographical distance or years. Thus, this study provided guidelines to build more accurate maize yield forecasting models, but also established limitations for up-scaling, from farm-level to county, district, and state-scales.Publicado originalmente en: Rai A. Schwalbert, Telmo J.C. Amado, Luciana Nieto, Sebastian Varela, Geomar M. Corassa, Tiago A.N. Horbe, Charles W. Rice, Nahuel R. Peralta, Ignacio A. Ciampitti. Forecasting maize yield at field scale based on high-resolution satellite imagery. Biosystem Engineering. 171: 179–192
DOI: https://doi.org/10.1016/j.biosystemseng.2018.04.020Sociedad Argentina de Informática e Investigación Operativ
Magnetic Field Generation in Stars
Enormous progress has been made on observing stellar magnetism in stars from
the main sequence through to compact objects. Recent data have thrown into
sharper relief the vexed question of the origin of stellar magnetic fields,
which remains one of the main unanswered questions in astrophysics. In this
chapter we review recent work in this area of research. In particular, we look
at the fossil field hypothesis which links magnetism in compact stars to
magnetism in main sequence and pre-main sequence stars and we consider why its
feasibility has now been questioned particularly in the context of highly
magnetic white dwarfs. We also review the fossil versus dynamo debate in the
context of neutron stars and the roles played by key physical processes such as
buoyancy, helicity, and superfluid turbulence,in the generation and stability
of neutron star fields.
Independent information on the internal magnetic field of neutron stars will
come from future gravitational wave detections. Thus we maybe at the dawn of a
new era of exciting discoveries in compact star magnetism driven by the opening
of a new, non-electromagnetic observational window.
We also review recent advances in the theory and computation of
magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo
theory. These advances offer insight into the action of stellar dynamos as well
as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field
generation in stars to appear in Space Science Reviews, Springe
Study of Tau-pair Production in Photon-Photon Collisions at LEP and Limits on the Anomalous Electromagnetic Moments of the Tau Lepton
Tau-pair production in the process e+e- -> e+e-tau+tau- was studied using
data collected by the DELPHI experiment at LEP2 during the years 1997 - 2000.
The corresponding integrated luminosity is 650 pb^{-1}. The values of the
cross-section obtained are found to be in agreement with QED predictions.
Limits on the anomalous magnetic and electric dipole moments of the tau lepton
are deduced.Comment: 20 pages, 9 figures, Accepted by Eur. Phys. J.
CP asymmetry in in a general two-Higgs-doublet model with fourth-generation quarks
We discuss the time-dependent CP asymmetry of decay in an
extension of the Standard Model with both two Higgs doublets and additional
fourth-generation quarks. We show that although the Standard Model with
two-Higgs-doublet and the Standard model with fourth generation quarks alone
are not likely to largely change the effective from the decay of
, the model with both additional Higgs doublet and
fourth-generation quarks can easily account for the possible large negative
value of without conflicting with other experimental
constraints. In this model, additional large CP violating effects may arise
from the flavor changing Yukawa interactions between neutral Higgs bosons and
the heavy fourth generation down type quark, which can modify the QCD penguin
contributions. With the constraints obtained from processes
such as and , this model can lead to the
effective to be as large as in the CP asymmetry of .Comment: 13 pages, 5 figures, references added, to appear in Eur.Phys.J.
Energy dependence of Cronin momentum in saturation model for and collisions
We calculate dependence of Cronin momentum for and
collisions in saturation model. We show that this dependence is consistent with
expectation from formula which was obtained using simple dimentional
consideration. This can be used to test validity of saturation model (and
distinguish among its variants) and measure dependence of saturation
momentum from experimental data.Comment: LaTeX2e, 12 pages, 8 figure
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