297 research outputs found
Genotype-Environment Interaction for Forage Yield of Vetch (\u3ci\u3eVicia sativa\u3c/i\u3e L.) in Mediterranean Environments
Genotype x environment (GE) interactions limit the effectiveness of selection when selection is based only on mean yields. The objective of this study was to evaluate the amount of GE interaction for vetch forage yield in some environments of Southern Italy, and to analyze some stability parameters that can be useful in the selection of genotypes adapted to Mediterranean environmental conditions. Eleven vetch genotypes were grown in a total of 16 environments in Southern Italy. The combined analysis of variance for forage yield showed that the environment, genotype and GE interaction terms were significant at 0.01 level, suggesting a broad range of genotype diversity and environmental variation. Production stability for yield was measured by computing five stability parameters: (i) mean forage yield, (ii) the regression coefficients of the yields of a genotype on to mean yields of the 16 environments (b), (iii) the deviations from regression mean square (sdi2), (iv) the determination coefficient (r2), and (v) the ranking indices (R1 and R2) of genotypes productivity. Phenotypic correlations between forage yield and stability parameters were also calculated. More than 90% of yield variability of single vetch genotype is due to the linear regression. The mean forage yield and the adaptability (b) and stability (sd2 and r2 ) parameters showed a significant variability. No significant correlation was observed between yield and adaptability and stability parameters, whereas the correlation between r2 and sd2 parameters was highly significant (r = – 0,978**). Three genotypes, useful for Mediterranean environments, were selected
Correlation functions by Cluster Variation Method for Ising model with NN, NNN and Plaquette interactions
We consider the procedure for calculating the pair correlation function in
the context of the Cluster Variation Methods. As specific cases, we study the
pair correlation function in the paramagnetic phase of the Ising model with
nearest neighbors, next to the nearest neighbors and plaquette interactions in
two and three dimensions. In presence of competing interactions, the so called
disorder line separates in the paramagnetic phase a region where the
correlation function has the usual exponential behavior from a region where the
correlation has an oscillating exponentially damped behavior. In two
dimensions, using the plaquette as the maximal cluster of the CVM
approximation, we calculate the phase diagram and the disorder line for a case
where a comparison is possible with results known in literature for the
eight-vertex model. In three dimensions, in the CVM cube approximation, we
calculate the phase diagram and the disorder line in some cases of particular
interest. The relevance of our results for experimental systems like mixtures
of oil, water and surfactant is also discussed.Comment: 31 pages, LaTeX file, 7 figure
Variation of Agronomic Traits in a World Collection of Vetch (\u3ci\u3eVicia sativa\u3c/i\u3e L.)
More than 850 accessions of vetch (Vicia sativa L.) representing 16 countries were obtained from the Italian Germplasm Institute and grown in a Southern Italy environment. The five following quantitative characters were analysed: days to harvest, plant dry weight, number of pods per plant, seed yield per plant, and seed yield per pod. The frequencies of various phenotypes were examined for total world collection and for each country in which there was a sufficient number of accessions. Wide phenotypic variability was observed for all characters, and usually within each country. The Shannon–Weaver diversity index (H\u27) was used to examine overall phenotypic diversity on a world and geographic basis. The total world collection showed a high diversity (H\u27= 0.872) and also the collections of substantial size (Turkey, FAO and Italy) showed a highly significant diversity index (H\u27= 0.826, 0.762, 0.801). A strong positive correlation was found between biomass and seed yield for total accessions (r = 0,794**) and for the accessions of some countries; these results indicate that simultaneous selection for both traits should be successful
Effect of Supplementary Irrigation on Yield of Chickpea Genotypes in a Mediterranean Climate
Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 8 (2006): Effect of Supplementary Irrigation on Yield of Chickpea Genotypes in a Mediterranean Climate. Manuscript LW 04 005. Vol. VIII. May, 2006
Coherent instabilities in a semiconductor laser with fast gain recovery
We report the observation of a coherent multimode instability in quantum
cascade lasers (QCLs), which is driven by the same fundamental mechanism of
Rabi oscillations as the elusive Risken-Nummedal-Graham-Haken (RNGH)
instability predicted 40 years ago for ring lasers. The threshold of the
observed instability is significantly lower than in the original RNGH
instability, which we attribute to saturable-absorption nonlinearity in the
laser. Coherent effects, which cannot be reproduced by standard laser rate
equations, can play therefore a key role in the multimode dynamics of QCLs, and
in lasers with fast gain recovery in general.Comment: 5 pages, 4 figure
Self-supervised Outdoor Scene Relighting
Outdoor scene relighting is a challenging problem that requires good
understanding of the scene geometry, illumination and albedo. Current
techniques are completely supervised, requiring high quality synthetic
renderings to train a solution. Such renderings are synthesized using priors
learned from limited data. In contrast, we propose a self-supervised approach
for relighting. Our approach is trained only on corpora of images collected
from the internet without any user-supervision. This virtually endless source
of training data allows training a general relighting solution. Our approach
first decomposes an image into its albedo, geometry and illumination. A novel
relighting is then produced by modifying the illumination parameters. Our
solution capture shadow using a dedicated shadow prediction map, and does not
rely on accurate geometry estimation. We evaluate our technique subjectively
and objectively using a new dataset with ground-truth relighting. Results show
the ability of our technique to produce photo-realistic and physically
plausible results, that generalizes to unseen scenes.Comment: Published in ECCV '20,
http://gvv.mpi-inf.mpg.de/projects/SelfRelight
Simplifying Consent for HIV Testing Is Associated with an Increase in HIV Testing and Case Detection in Highest Risk Groups, San Francisco January 2003–June 2007
Populations at highest risk for HIV infection face multiple barriers to HIV testing. To facilitate HIV testing procedures, the San Francisco General Hospital Medical Center eliminated required written patient consent for HIV testing in its medical settings in May 2006. To describe the change in HIV testing rates in different hospital settings and populations after the change in HIV testing policy in the SFDH medical center, we performed an observational study using interrupted time series analysis.Data from all patients aged 18 years and older seen from January 2003 through June 2007 at the San Francisco Department of Public Health (SFDPH) medical care system were included in the analysis. The monthly HIV testing rate per 1000 had patient-visits was calculated for the overall population and stratified by hospital setting, age, sex, race/ethnicity, homelessness status, insurance status and primary language.By June 2007, the average monthly rate of HIV tests per 1000 patient-visits increased 4.38 (CI, 2.17-6.60, p<0.001) over the number predicted if the policy change had not occurred (representing a 44% increase). The monthly average number of new positive HIV tests increased from 8.9 (CI, 6.3-11.5) to 14.9 (CI, 10.6-19.2, p<0.001), representing a 67% increase. Although increases in HIV testing were seen in all populations, populations at highest risk for HIV infection, particularly men, the homeless, and the uninsured experienced the highest increases in monthly HIV testing rates after the policy change.The elimination of the requirement for written consent in May 2006 was associated with a significant and sustained increase in HIV testing rates and HIV case detection in the SFDPH medical center. Populations facing the higher barriers to HIV testing had the highest increases in HIV testing rates and case detection in response to the policy change
Similarity Patterns and Stability of Environmental Response in Sunflower Hybrids
The rationale for the following research was to analyse the response of sunflower hybrids to different sowing dates and to evaluate hybrid response to critical environmental conditions. The data used are from an experiment conducted in a location-year combination over a period of two years (2007-09) in southern Italy. Eleven hybrids were tested following a randomized complete block design with three replications at each location-year combination. Eight agronomic characters including seed oil content were recorded. Classification and ordination procedures were used to investigate hybrid performance in relation to three different sowing dates. Combined analysis of variance showed that hybrids, location-year combination, sowing date and their interactions were highly significant for all characters. Hybrid performances were classified by cluster analysis into groups that were differentiable in terms of means and stability. The first three components accounted for 74%, 82%, and 87% of the total variation for the first, second and third sowing date respectively. Plotting component one against component two along Euclidean axes should therefore provide a reasonable representation of the spatial arrangements of hybrid performances in the original multi-dimensional space. The applied statistical method gives full information on hybrid performances similarity
An Earth-system prediction initiative for the twenty-first century
International audienceSome scientists have proposed the Earth-System Prediction Initiative (EPI) at the 2007 GEO Summit in Cape Town, South Africa. EPI will draw upon coordination between international programs for Earth system observations, prediction, and warning, such as the WCRP, WWRP, GCOS, and hence contribute to GEO and the GEOSS. It will link with international organizations, such as the International Council for Science (ICSU), Intergovernmental Oceanographic Commission (IOC), UNEP, WMO, and World Health Organization (WHO). The proposed initiative will provide high-resolution climate models that capture the properties of regional high-impact weather events, such as tropical cyclones, heat wave, and sand and dust storms associated within multi-decadal climate projections of climate variability and change. Unprecedented international collaboration and goodwill are necessary for the success of EPI
A parametric model for wind turbine power curves incorporating environmental conditions
A wind turbine's power curve relates its power production to the wind speed it experiences. The typical shape of a power curve is well known and has been studied extensively. However, power curves of individual turbine models can vary widely from one another. This is due to both the technical features of the turbine (power density, cut-in and cut-out speeds, limits on rotational speed and aerodynamic efficiency), and environmental factors (turbulence intensity, air density, wind shear and wind veer). Data on individual power curves are often proprietary and only available through commercial databases. We therefore develop an open-source model for pitch regulated horizontal axis wind turbine which can generate the power curve of any turbine, adapted to the specific conditions of any site. This can employ one of six parametric models advanced in the literature, and accounts for the eleven variables mentioned above. The model is described, the impact of each technical and environmental feature is examined, and it is then validated against the manufacturer power curves of 91 turbine models. Versions of the model are made available in MATLAB, R and Python code for the community
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