2,948 research outputs found
Gravitational lens candidates in the E-CDFS
We report ten lens candidates in the E-CDFS from the GEMS survey. Nine of the
systems are new detections and only one of the candidates is a known lens
system. For the most promising five systems including the known lens system, we
present results from preliminary lens mass modelling, which tests if the
candidates are plausible lens systems. Photometric redshifts of the candidate
lens galaxies are obtained from the COMBO-17 galaxy catalog. Stellar masses of
the candidate lens galaxies within the Einstein radius are obtained by using
the -band luminosity and the color-based stellar mass-to-light ratios.
As expected, the lensing masses are found to be larger than the stellar masses
of the candidate lens galaxies. These candidates have similar dark matter
fractions as compared to lenses in SLACS and COSMOS. They also roughly follow
the halo mass-stellar mass relation predicted by the subhalo abundance matching
technique. One of the candidate lens galaxies qualifies as a LIRG and may not
be a true lens because the arc-like feature in the system is likely to be an
active region of star formation in the candidate lens galaxy. Amongst the five
best candidates, one is a confirmed lens system, one is a likely lens system,
two are less likely to be lenses and the status of one of the candidates is
ambiguous. Spectroscopic follow-up of these systems is still required to
confirm lensing and/or for more accurate determination of the lens masses and
mass density profiles.Comment: 12 pages, 5 figures, 3 tables, ApJ accepte
SARCS strong lensing galaxy groups: I - optical, weak lensing, and scaling laws
We present the weak lensing and optical analysis of the SL2S-ARCS (SARCS)
sample of strong lens candidates. The sample is based on the Strong Lensing
Legacy Survey (SL2S), a systematic search of strong lensing systems in the
photometric Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). The SARCS
sample focuses on arc-like features and is designed to contain mostly galaxy
groups. We briefly present the weak lensing methodology that we use to estimate
the mass of the SARCS objects. Among 126 candidates, we obtain a weak lensing
detection for 89 objects with velocity dispersions of the Singular Isothermal
Sphere mass model ranging from 350 to 1000 km/s with an average value of
600km/s, corresponding to a rich galaxy group (or poor cluster). From the
galaxies belonging to the bright end of the group's red sequence (M_i<-21), we
derive the optical properties of the SARCS candidates. We obtain typical
richnesses of N=5-15 galaxies and optical luminosities of L=0.5-1.5e+12 Lsol
(within a radius of 0.5 Mpc). We use these galaxies to compute luminosity
density maps, from which a morphological classification reveals that a large
fraction of the sample are groups with a complex light distribution, either
elliptical or multimodal, suggesting that these objects are dynamically young
structures. We finally combine the lensing and optical analyses to draw a
sample of 80 most secure group candidates, i.e. weak lensing detection and
over-density at the lens position in the luminosity map, to remove false
detections and galaxy-scale systems from the initial sample. We use this
reduced sample to probe the optical scaling relations in combination with a
sample of massive galaxy clusters. We detect the expected correlations over the
probed range in mass with a typical scatter of 25% in the SIS velocity
dispersion at a given richness or luminosity, making these scaling laws
interesting mass proxie
Taxonomic studies of Eulophid parasitoids (Hymenoptera: Chalcidoidea) collected from Uttarakhand, India
A sound taxonomic knowledge base is a prerequisite for effective conservation, environment assessment, ecological research, management and sustainable use of biological resources. Parasitoids are the major component of the biocontrol, so the correct identification of the parasitoid is very important task. Eulophidae is a large family of the superfamily Chalcidoidea and comprises promising biocontrol agents for the control of insect pests causing harm to agricultural ecosystem. The present study has been done to provide the account and occurrence of 4 genera belonging to subfamily Entedoninae, Eulophinae and Tetrastichinae. Entedon costalis Dalman, Diglyphus horticola Khan, Hemiptarsenus varicornis (Girault), and Neotrichoporoides viridimaculatus (Fullaway) was collected from Uttarakhand (India) and described in detail with additional morphological characters that aids in clear identification of the parasitoids. Entedon costalis is recorded from this region with additional characters for identification
Generalised Decision Level Ensemble Method for Classifying Multi-media Data
In recent decades, multimedia data have been commonly generated and used in various domains, such as in healthcare and social media due to their ability of capturing rich information. But as they are unstructured and separated, how to fuse and integrate multimedia datasets and then learn from them eectively have been a main challenge to machine learning. We present a novel generalised decision level ensemble method (GDLEM) that combines the multimedia datasets at decision level. After extracting features from each of multimedia datasets separately, the method trains models independently on each media dataset and then employs a generalised selection function to choose the appropriate models to construct a heterogeneous ensemble. The selection function is dened as a weighted combination of two criteria: the accuracy of individual models and the diversity among the models. The framework is tested on multimedia data and compared with other heterogeneous ensembles. The results show that the GDLEM is more exible and eective
Post Disaster Management of Mithi River Flood after July -2005 by HAVOC
The disaster of Mumbai, July 2005 a galvanised the concerned agencies into recognising the importance of the river, which in fact flows through the heart of Mumbai Suburbs. The authorities were willing now to recognise that the Mithi was a "river" and not a "nalla". The Mithi River Development and Protection Authority was established to initiate the study to identify the causes of pollution affecting the river and to suggest remedial measures. The authority conducted and environmental survey of the Mithi River to determine the pollution level of its water. I have tried to analyse the situation and have suggested guidelines for immediate actions as well as for long term measures. I have refrained from working out specific details of any proposals and it will be done as required by the concerned public agencies keeping in view of the guidelines suggested in this paper. Ours has not been a fault finding mission, but a serious exercise to understand as to which deficiencies need to be overcome, so as to be able to face calamitous situations as on 26th and 27th July,2005 in a better prepared way. We hope that our findings will help Mumbaikar?s to move in the right direction rapidly and with confidence
Efficacy of sequential sprays of different fungicides against early blight Alternaria solani (Ellis and Martin) in potato Solanum tubrosum L.
Potato is one of the world's fourth most important food crop belongs to family solanaceae. More than one billion peoples consume potatoes and richest source of energy highest dry matter, energy and edible proteins. The field experiments on Efficacy of sequential sprays of different fungicides against early blight Alternaria solani (Ellis and Martin) in potato Solanum tubrosum L. was conducted during kharif season on potato (cv. K. Pukharaj) for consecutive three years. The experiment was laid out in RBD design with 6 treatments and 4 replications. The results revealed that spray of Chlorothalonil 75 WP (0.25%) @ 2.5 gm/ liter of water followed by Hexaconazole 5 EC (0.05%) @ 0.5 ml /liter of water and then Chlorothalonil 75WP (0.25%) @ 2.5 gm/liter of water at 10 days interval was found significantly superior in controlling the early blight on potato The yield differences due to spraying of fungicides were significant and the highest yield (18.10 t/ha) was obtained in same treatment
Distanciamiento social ante la COVID-19: Simulación del aforo máximo de personas mediante PHP
Population confluence in internal or external areas considerably increases transmission of COVID-19, due to not respecting the social distancing established by the health system. The objective of this work was to make use of programming techniques,
using the PHP language (hypertext preprocessor), for the development of an application that simulates the maximum capacity of people who can enter an internal or external area. The methodology allowed recognizing common internal and external areas, configurating to the development environment, coding, simulation proposing and executing of the simulator where a practical case and ten places were evaluated to determine its reliability. The simulator provided the maximum capacity of people who can enter an internal or external area, complying with the social distancing of 2 m. The results made it possible to know that the use of information technologies through programming techniques and the PHP language contributed to being a technological alternative for the fight against the spread of the virus.La confluencia poblacional en áreas internas o externas incrementa considerablemente la trasmisión de la COVID-19, por no respetar el distanciamiento social que establece el sistema de salud. El objetivo de este trabajo fue hacer uso de técnicas de programación, empleando el lenguaje PHP (preprocesador de hipertexto), para el desarrollo de una aplicación que simule el aforo máximo de personas que pueden ingresar a un área interna o externa. La metodología permitió el reconocimiento de áreas internas y externas comunes, configuración al entorno de desarrollo, codificación, propuesta de simulación y ejecución del simulador donde se ha evaluado un caso práctico y diez lugares para determinar su confiabilidad. El simulador brindó el aforo máximo de personas que pueden ingresar a un lugar de área interna o externa cumpliendo el distanciamiento social de 2 m. Los resultados permitieron conocer que el uso de las tecnologías de información a través de las técnicas de programación y el lenguaje PHP contribuyó en ser una alternativa tecnológica para la lucha contra la propagación del virus
A spectral function tour of electron-phonon coupling outside the Migdal limit
We simulate spectral functions for electron-phonon coupling in a filled band
system - far from the asymptotic limit often assumed where the phonon energy is
very small compared to the Fermi energy in a parabolic band and the Migdal
theorem predicting 1+lambda quasiparticle renormalizations is valid. These
spectral functions are examined over a wide range of parameter space through
techniques often used in angle-resolved photoemission spectroscopy (ARPES).
Analyzing over 1200 simulations we consider variations of the microscopic
coupling strength, phonon energy and dimensionality for two models: a
momentum-independent Holstein model, and momentum-dependent coupling to a
breathing mode phonon. In this limit we find that any `effective coupling',
lambda_eff, inferred from the quasiparticle renormalizations differs from the
microscopic dimensionless coupling characterizing these Hamiltonians, lambda,
and could drastically either over- or under-estimate it depending on the
particular parameters and model. In contrast, we show that perturbation theory
retains good predictive power for low coupling and small momenta, and that the
momentum-dependence of the self-energy can be revealed via the relationship
between velocity renormalization and quasiparticle strength. Additionally we
find that (although not strictly valid) it is often possible to infer the
self-energy and bare electronic structure through a self-consistent
Kramers-Kronig bare-band fitting; and also that through lineshape alone, when
Lorentzian, it is possible to reliably extract the shape of the imaginary part
of a momentum-dependent self-energy without reference to the bare-band.Comment: 15 pages, 11 figures. High resolution available here:
http://www.physics.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/sf_tour.pd
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