Shapes and Shears, Stars and Smears: Optimal Measurements for Weak Lensing

We present the theoretical and analytical bases of optimal techniques to measure weak gravitational shear from images of galaxies. We first characterize the geometric space of shears and ellipticity, then use this geometric interpretation to analyse images. The steps of this analysis include: measurement of object shapes on images, combining measurements of a given galaxy on different images, estimating the underlying shear from an ensemble of galaxy shapes, and compensating for the systematic effects of image distortion, bias from PSF asymmetries, and `"dilution" of the signal by the seeing. These methods minimize the ellipticity measurement noise, provide calculable shear uncertainty estimates, and allow removal of systematic contamination by PSF effects to arbitrary precision. Galaxy images and PSFs are decomposed into a family of orthogonal 2d Gaussian-based functions, making the PSF correction and shape measurement relatively straightforward and computationally efficient. We also discuss sources of noise-induced bias in weak lensing measurements and provide a solution for these and previously identified biases.Comment: Version accepted to AJ. Minor fixes, plus a simpler method of shape weighting. Version with full vector figures available via http://www.astro.lsa.umich.edu/users/garyb/PUBLICATIONS

A Deep Multicolor Survey. VI. Near-Infrared Observations, Selection Effects, and Number Counts

I present near-infrared J (1.25um), H (1.65um), and K (2.2um) imaging observations of 185 square arcminutes in 21 high galactic latitude fields. These observations reach limiting magnitudes of J ~ 21 mag, H ~ 20 mag and K ~ 18.5 mag. The detection efficiency, photometric accuracy and selection biases as a function of integrated object brightness, size, and profile shape are quantified in detail. I evaluate several popular methods for measuring the integrated light of faint galaxies and show that only aperture magnitudes provide an unbiased measure of the integrated light that is independent of apparent magnitude. These J, H, and K counts and near-infrared colors are in best agreement with passive galaxy formation models with at most a small amount of merging (for Omega_M = 0.3, Omega_Lambda = 0.7).Comment: AJ Accepted (Feb 2001). 28 pages, 7 embedded ps figures, AASTEX5. Minor changes to submitted version. Also available at http://www.astronomy.ohio-state.edu/~martini/pubs

The Evaluation and Use of a Food Frequency Questionnaire Among the Population in Trivandrum, South Kerala, India

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Dietary record tools such as food frequency questionnaire (FFQ) and food diaries (FD) are the most commonly used choices for assessing dietary intakes in most large-scale epidemiological studies. The authors developed a self-administered 360-item food frequency questionnaire (FFQ) to assess dietary intakes amongst a population-based cohort in South Kerala. In the validation study (n = 460), the data were collected using FFQs that were administered on three different occasions which were then compared to 7-day food records. The intake of foods and nutrients was higher as determined by the FFQ than that assessed using food records. Spearman correlations for macro-nutrients ranged from 0.72 for protein to 0.61 for carbohydrates and for micronutrients, from 0.71 for vitamin B6 to 0.34 for magnesium. The correlation was improved with energy-adjusted nutrient intakes. On average, the exact agreement for the macronutrients ranged from 48.2% to 57.1%, and that for micronutrients ranged from 66.7% to 41.9%, with the median percentage of 49.58%. The authors conclude that the FFQ has an acceptable reproducibility, however, there was a systematic trend towards higher estimates with the FFQ for most nutrients compared to the FD records

Influence of exogenous enzymes in presence of Salix babylonica extract on digestibility, microbial protein synthesis and performance of lambs fed maize silage

In Mexico, there are native trees that can be used as an alternative feed when forages are scarce and of poor quality in the dry season (Palma et al. 1995). However, the use of plants or their extracts as feed additives is restricted by their secondary compound content (Salem et al. 2014c): although the ideal concentrations can modify and support the utilization of nutrients in the rumen (Salem et al. 2014a, b, c), an inverse relationship between secondary compound concentration and animal performance has been observed (Vasta & Luciano 2011; Salem et al. 2011a, 2013).Sixteen Suffolk lambs with 29 ± 2·0 kg body weight were housed in individual cages for 60 days and allotted to four treatments in a completely randomized design to determine the effect of administration of Salix babylonica (SB) extract and/or exogenous enzymes (ZADO®) on lamb performance. Lambs were fed with 300 g/kg concentrate (160 g crude protein (CP)/kg, 13·4 MJ metabolizable energy (ME)/kg dry matter (DM)) and 700 g/kg maize silage (80 g/kg CP, 11·7 MJ ME/kg DM) as a basal diet (control). Another three treatments were tested; the SB extract was administered at 30 ml/day (SB) and exogenous enzymes ZADO® (i.e. an exogenous enzyme cocktail in a powder form) directly fed at 10 g/day (EZ), while the last treatment contained ZADO® at 10 g/day + SB extract at 30 ml/day (EZSB). Lambs of the treatment EZSB had the greatest average daily weight gain (ADG) and feed conversion throughout the period of the experiment. However, during the first 30 days SB was more effective for ADG than EZ and vice versa during the last 30 days of the experiment.Water consumption was greater for SB, followed by EZ and EZSB compared to the control. Intakes ofDMand organicmatter (OM) were the highest in EZSB followed by EZ, which had the greatest neutral detergent fibre, acid detergent fibre (ADF) and nitrogen (N) intakes. The EZSB treatment had the greatest DM and OM digestibilities compared to the other treatments; however, SB had the greatest ADF digestibility. Combination of EZ and SB had the best N balance. Allantoin, total purine derivatives (PD), allantoin : -creatinine ratio, and PD: creatinine ratio were increased in EZSB compared to the other treatments. However, EZ supplementation increased uric acid concentration, whereas the microbial N (g N/day) and metabolizable protein (g N/day) were increased in EZSB versus the other treatments. It can be concluded that addition of 10 g ZADO® in combination with S. babylonica extract at 30 ml/day in the diet of lambs increased feed intake, nutrient digestibility and daily gain, with a positive impact on the use of N and microbial protein synthesis

A Study of Nine High-Redshift Clusters of Galaxies: IV. Photometry and Sp ectra of Clusters 1324+3011 and 1604+4321

New photometric and spectroscopic observations of galaxies in the directions of three distant clusters are presented as part of our on-going high-redshift cluster survey. The clusters are CL1324+3011 at z = 0.76, CL1604+4304 at z = 0.90, and CL1604+4321 at z = 0.92. The observed x-ray luminosities in these clusters are at least a factor of 3 smaller than those observed in clusters with similar velocity dispersions at z <= 0.4. These clusters contain a significant population of elliptical-like galaxies, although these galaxies are not nearly as dominant as in massive clusters at z <= 0.5. We also find a large population of blue cluster members. Defining an active galaxy as one in which the rest equivalent width of [OII] is greater than 15 Angstroms, the fraction of active cluster galaxies, within the central 1.0 Mpc, is 45%. In the field population, we find that 65% of the galaxies with redshifts between z = 0.40 and z = 0.85 are active, while the fraction is 79% for field galaxies at z > 0.85. The star formation rate normalized by the rest AB B-band magnitude, SFRN, increases as the redshift increases at a given evolving luminosity. At a given redshift, however, SFRN decreases linearly with increasing luminosity indicating a remarkable insensitivity of the star formation rate to the intrinsic luminosity of the galaxy over the range -18 >= ABB >= -22. Cluster galaxies in the central 1 Mpc regions exhibit depressed star formation rates. We are able to measure significant evolution in the B-band luminosity function over the range 0.1 <= z <= 1. The characteristic luminosity increases by a factor of 3 with increasing redshift over this range.Comment: 64 pages, 18 figures, accepted for publication in the Astronomical Journal on May 25, 2001. Scheduled to appear in Sept 2001 issu

A Magellan-IMACS-IFU Search for Dynamical Drivers of Nuclear Activity. I. Reduction Pipeline and Galaxy Catalog

Using the Inamori Magellan Areal Camera and Spectrograph (IMACS) integral-field unit (IFU) on the 6.5m Magellan telescope, we have designed the first statistically significant investigation of the two-dimensional distribution and kinematics of ionized gas and stars in the central kiloparsec regions of a well-matched sample of Seyfert and inactive control galaxies selected from the Sloan Digital Sky Survey. The goals of the project are to use the fine spatial sampling (0.2 arcsec/pixel) and large wavelength coverage (4000-7000A) of the IMACS-IFU to search for dynamical triggers of nuclear activity in the central region where active galactic nucleus (AGN) activity and dynamical timescales become comparable, to identify and assess the impact of AGN-driven outflows on the host galaxy and to provide a definitive sample of local galaxy kinematics for comparison with future three-dimensional kinematic studies of high-redshift systems. In this paper, we provide the first detailed description of the procedure to reduce and calibrate data from the IMACS-IFU in `long mode' to obtain two-dimensional maps of the distribution and kinematics of ionized gas and stars. The sample selection criteria are presented, observing strategy described and resulting maps of the sample galaxies presented along with a description of the observed properties of each galaxy and the overall observed properties of the sample.Comment: 62 pages. 41 figures. 5 tables. Accepted for publication in ApJS. High-resolution version available at: http://www.astro.ljmu.ac.uk/~pbw/IMACS-IFU/IMACS-1-highRes.pd

Using knowledge: the dilemmas of 'bridging research and policy'

The 'knowledge agenda' has become a central part of development discourse. This paper addresses one aspect of this discourse - the use of policy research in the social sciences - and the dilemmas that have been encountered by both development agencies and researchers in communicating and making use of that research. Development agencies as well as NGOs have initiated work to evaluate and document the effectiveness of research partnerships, knowledge capacity building and (social) science policy impact. As a multilateral initiative, the Global Development Network (GDN), and especially its 'Bridging Research and Policy' project, provides a vehicle to address issues related to research impact. Twelve perspectives on improving research and policy linkages are outlined to reveal that how the problem is defined shapes policy responses. Taken together, these explanations provide a multifaceted picture of the research-policy nexus indicating that there are many possible routes to 'bridging' research and policy. These diverse perspectives will be categorised into three broad categories of explanation: (i) supply-side; (ii) demand-led; and (iii) policy currents. However, knowledge is part of the solution to many development problems but not of itself a panacea

Adenosine Deaminase Activity Is a Sensitive Marker for the Diagnosis of Tuberculous Pleuritis in Patients with Very Low CD4 Counts

Background: Adenosine Deaminase Activity (ADA) is a commonly used marker for the diagnosis of tuberculous pleural effusion. There has been concern about its usefulness in immunocompromised patients, especially HIV positive patients with very low CD4 counts. The objective of this study was to evaluate the sensitivity of ADA in pleural fluid in patients with low CD4 counts. Materials and Methods: This was a retrospective case control study. Medical files of patients with tuberculous pleuritis and non-tuberculous pleuritis were reviewed. Clinical characteristics, CD4 cell counts in blood and biochemical markers in pleural fluid, including ADA were recorded. Results: One ninety seven tuberculous pleuritis and 40 non- tuberculous pleuritis patients were evaluated. Using the cut-off value of 30 U/L, the overall sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of ADA was 94%, 95%, 19, and 0.06 respectively. The mean CD4 cell counts among TB pleuritis patients was 29 and 153 cells/microL in patients with CD4 ,50 cells/microL and .50 cells/microL, (p,0.05) respectively. The corresponding mean ADA values for these patients were 76 U/L and 72 U/L respectively (p.0.5). There was no correlation between ADA values and CD4 cell counts (r =20.120, p = 0.369). Conclusion: ADA analysis is a sensitive marker of tuberculous pleuritis even in HIV patients with very low CD4 counts in a high TB endemic region. The ADA assay is inexpensive, rapid, and simple to perform and is of great value for the immediate diagnosis of tuberculous pleuritis while waiting for culture result and this has a positive impact on patient outcome