233 research outputs found
Heritability and genetic correlations between enteric methane production and concentration recorded by GreenFeed and sniffers on dairy cows
To reduce methane (CH4) emissions of dairy cows by animal breeding, CH4 measurements have to be recorded on thousands of individual cows. Currently, several techniques are used to phenotype cows for CH4, differing in costs and applicability. However, there is uncertainty about the agreement between techniques. To judge the similarity and repeatability between measurements of different recording techniques, the repeatability, heritability, and genetic correlation are useful metrics. Therefore, our objective was to estimate (1) the repeatability and heritability for CH4 and carbon dioxide production recorded by GreenFeed (GF) and for CH4 and carbon dioxide concentration measured by cost-effective but less accurate sniffers, and (2) the genetic correlation between CH4 recorded with these 2 different on farm and high throughput techniques. Data were available from repeated measurements of CH4 production (grams/day) by GF units and of CH4 concentration (ppm) by sniffers, recorded on commercial dairy farms in the Netherlands. The final data comprised 24,284 GF daily means from 822 cows, 170,826 sniffer daily means from 1,800 cows, and 1,786 daily means from 75 cows by both GF and sniffer (in the same period). Additionally, CH4 records were averaged per week. For daily and weekly mean GF CH4 the heritabilities were 0.19 ± 0.02 and 0.33 ± 0.04, and for daily and weekly mean sniffer CH4 the heritabilities were similar and were 0.18 ± 0.01 and 0.32 ± 0.02, respectively. Phenotypic correlations between GF CH4 production and sniffer CH4 concentration were moderate (0.39 ± 0.03 for daily means and 0.37 ± 0.05 for weekly means). However, genetic correlations were high" 0.71 ± 0.13 for daily means and 0.76 ± 0.15 for weekly means. The high genetic correlation indicates that selection on low CH4 concentrations (ppm) recorded by the cost-effective sniffer method, will result in reduced CH4 production (grams/day) as recorded with GF
Heritability and genetic correlations of enteric methane emissions of dairy cows measured by sniffers and GreenFeed
Before methane (CH4) emission can be mitigated with animal breeding, breath measurements have to be recorded on a large number of cows. Our aim was to estimate heritabilities for, and a genetic correlation between, CH4 recorded by GreenFeed and sniffers. Repeated records were available for CH4 production (g/cow/day) by GreenFeed and for CH4 concentration (ppm) by sniffers. The data included 24,284 GreenFeed daily means from 822 cows, 172,948 sniffer daily means from 1,800 cows, and 1,787 daily means from both devices on the same day from 75 cows. Additionally, records were averaged per week. The datasets were analyzed using bivariate animal models. The results show that CH4 emissions recorded by either device has a moderate heritability (0.18-0.37). Furthermore, the genetic correlation between weekly mean CH4 recorded by GreenFeed or by sniffers was high (0.77). This suggest that the measurements can be used in the same genetic evaluations
Association of cardiovascular risk factors with carotid intima media thickness in patients with rheumatoid arthritis with low disease activity compared to controls: A cross-sectional study
Objectives Rheumatoid arthritis (RA) has been identified as an independent cardiovascular risk factor. The importance of risk factors such as hypertension and hyperlipidemia in the generation of atherosclerosis in RA patients is unclear. This study analyzed clinical parameters associated with carotid intima media thickness (cIMT) in patients with RA. Methods Subjects with RA and healthy controls without RA, both without known cardiovascular disease, were included. Participants underwent a standard physical examination and laboratory measurements including a lipid profile. cIMT was measured semi-automatically by ultrasound. Results In total 243 RA patients and 117 controls were included. The median RA disease duration was 7 years (IQ
The Subaru/XMM-Newton Deep Field - II. The 37 brightest radio sources
We study the 37 brightest radio sources in the Subaru/XMM-Newton Deep Field
(SXDF). We have spectroscopic redshifts for 24 of 37 objects and photometric
redshifts for the remainder, yielding a median redshift z_med for the whole
sample of z_med ~= 1.1 and a median radio luminosity close to the `FRI/FRII'
luminosity divide. Using mid-IR (Spitzer MIPS 24 um) data we expect to trace
nuclear accretion activity, even if it is obscured at optical wavelengths,
unless the obscuring column is extreme. Our results suggest that above the
FRI/FRII radio luminosity break most of the radio sources are associated with
objects that have excess mid-IR emission, only some of which are broad-line
objects, although there is one clear low-accretion-rate object with an FRI
radio structure. For extended steep-spectrum radio sources, the fraction of
objects with mid-IR excess drops dramatically below the FRI/FRII luminosity
break, although there exists at least one high-accretion-rate `radio-quiet'
QSO. We have therefore shown that the strong link between radio luminosity (or
radio structure) and accretion properties, well known at z ~ 0.1, persists to z
~ 1. Investigation of mid-IR and blue excesses shows that they are correlated
as predicted by a model in which, when significant accretion exists, a torus of
dust absorbs ~30% of the light, and the dust above and below the torus scatters
>~1% of the light.Comment: Accepted for publication by MNRAS; 39 pages, 7 figures, 4 table
Critique and Review of Leader-Member Exchange Theory: Issues of Agreement, Consensus, and Excellence
The relationship quality that develops between leaders and those designated as followers is of longstanding interest to researchers and practitioners. The purpose of the present article is to review the more recent developments in the field of leader-member exchange (LMX) theory to identify specific issues related to leader-member agreement and follower consensus that have potentially important theoretical and practical implications. We introduce the concept of LMX excellence, which involves high-quality LMX, high leader-member agreement as well as high group consensus in LMX quality. We outline how leaders and followers' behaviour as well as context can enhance or hinder the development of LMX excellence and conclude with an overview of the practical and theoretical implications as well as future research needs
Current challenges in software solutions for mass spectrometry-based quantitative proteomics
This work was in part supported by the PRIME-XS project, grant agreement number 262067, funded by the European Union seventh Framework Programme; The Netherlands Proteomics Centre, embedded in The Netherlands Genomics Initiative; The Netherlands Bioinformatics Centre; and the Centre for Biomedical Genetics (to S.C., B.B. and A.J.R.H); by NIH grants NCRR RR001614 and RR019934 (to the UCSF Mass Spectrometry Facility, director: A.L. Burlingame, P.B.); and by grants from the MRC, CR-UK, BBSRC and Barts and the London Charity (to P.C.
Clusters of Galaxies in the First Half of the Universe from the IRAC Shallow Survey
We have identified 335 galaxy cluster and group candidates, 106 of which are
at z > 1, using a 4.5 um selected sample of objects from a 7.25 deg^2 region in
the Spitzer Infrared Array Camera (IRAC) Shallow Survey. Clusters were
identified as 3-dimensional overdensities using a wavelet algorithm, based on
photometric redshift probability distributions derived from IRAC and NOAO Deep
Wide-Field Survey data. We estimate only ~10% of the detections are spurious.
To date 12 of the z > 1 candidates have been confirmed spectroscopically, at
redshifts from 1.06 to 1.41. Velocity dispersions of ~750 km/s for two of these
argue for total cluster masses well above 10^14 M_sun, as does the mass
estimated from the rest frame near infrared stellar luminosity. Although not
selected to contain a red sequence, some evidence for red sequences is present
in the spectroscopically confirmed clusters, and brighter galaxies are
systematically redder than the mean galaxy color in clusters at all redshifts.
The mean I - [3.6] color for cluster galaxies up to z ~ 1 is well matched by a
passively evolving model in which stars are formed in a 0.1 Gyr burst starting
at redshift z_f = 3. At z > 1, a wider range of formation histories is needed,
but higher formation redshifts (i.e. z_f > 3) are favored for most clusters.Comment: 56 pages, 19 figures, 3 tables, landscape tables 1 (p. 14) and 2 (p.
29) should be printed separately. Accepted for publication in Astrophysical
Journal, updated version will be posted upon publicatio
The longitudinal relationship between job mobility, perceived organizational justice, and health
<p>Abstract</p> <p>Background</p> <p>The main purpose of the present study was to examine the 2-year longitudinal and reciprocal relationship between job mobility and health and burnout. A second aim was to elucidate the effects of perceived organizational justice and turnover intentions on the relationship between job mobility (non-, internally and externally mobile), and health (SF-36) and burnout (CBI).</p> <p>Methods</p> <p>The study used questionnaire data from 662 Swedish civil servants and the data were analysed with Structural Equation Modeling statistical methods.</p> <p>Results</p> <p>The results showed that job mobility was a better predictor of health and burnout, than health and burnout were as predictors of job mobility. The predictive effects were most obvious for psychosocial health and burnout, but negligible as far as physical health was concerned. Organizational justice was found to have a direct impact on health, but not on job mobility; whereas turnover intentions had a direct effect on job mobility.</p> <p>Conclusion</p> <p>The predictive relationship between job mobility and health has practical implications for health promotive actions in different organizations.</p
The WiggleZ Dark Energy Survey: Survey Design and First Data Release
The WiggleZ Dark Energy Survey is a survey of 240,000 emission line galaxies
in the distant universe, measured with the AAOmega spectrograph on the 3.9-m
Anglo-Australian Telescope (AAT). The target galaxies are selected using
ultraviolet photometry from the GALEX satellite, with a flux limit of NUV<22.8
mag. The redshift range containing 90% of the galaxies is 0.2<z<1.0. The
primary aim of the survey is to precisely measure the scale of baryon acoustic
oscillations (BAO) imprinted on the spatial distribution of these galaxies at
look-back times of 4-8 Gyrs. Detailed forecasts indicate the survey will
measure the BAO scale to better than 2% and the tangential and radial acoustic
wave scales to approximately 3% and 5%, respectively.
This paper provides a detailed description of the survey and its design, as
well as the spectroscopic observations, data reduction, and redshift
measurement techniques employed. It also presents an analysis of the properties
of the target galaxies, including emission line diagnostics which show that
they are mostly extreme starburst galaxies, and Hubble Space Telescope images,
which show they contain a high fraction of interacting or distorted systems. In
conjunction with this paper, we make a public data release of data for the
first 100,000 galaxies measured for the project.Comment: Accepted by MNRAS; this has some figures in low resolution format.
Full resolution PDF version (7MB) available at
http://www.physics.uq.edu.au/people/mjd/pub/wigglez1.pdf The WiggleZ home
page is at http://wigglez.swin.edu.au
Modelling high redshift Lyman-alpha Emitters
We present a new model for high redshift Lyman-Alpha Emitters (LAEs) in the
cosmological context which takes into account the resonant scattering of Ly-a
photons through expanding gas. The GALICS semi-analytic model provides us with
the physical properties of a large sample of high redshift galaxies. We
implement a gas outflow model for each galaxy based on simple scaling
arguments. The coupling with a library of numerical experiments of Ly-a
transfer through expanding or static dusty shells of gas allows us to derive
the Ly-a escape fractions and profiles. The predicted distribution of Ly-a
photons escape fraction shows that galaxies with a low star formation rate have
a f_esc of the order of unity, suggesting that, for those objects, Ly-a may be
used to trace the star formation rate assuming a given conversion law. In
galaxies forming stars intensely, the escape fraction spans the whole range
from 0 to 1. The model is able to get a good match to the UV and Ly-a
luminosity function (LF) data at 3 < z < 5. We find that we are in good
agreement with both the bright Ly-a data and the faint population observed by
Rauch et al. (2008) at z=3. Most of the Ly-a profiles of our LAEs are
redshifted by the diffusion in the outflow which suppresses IGM absorption. The
bulk of the observed Ly-a equivalent width (EW) distribution is recovered by
our model, but we fail to obtain the very large values sometimes detected.
Predictions for stellar masses and UV LFs of LAEs show a satisfactory agreement
with observational estimates. The UV-brightest galaxies are found to show only
low Ly-a EWs in our model, as it is reported by many observations of high
redshift LAEs. We interpret this effect as the joint consequence of old stellar
populations hosted by UV-bright galaxies, and high HI column densities that we
predict for these objects, which quench preferentially resonant Ly-a photons
via dust extinction.Comment: 17 pages, 12 figures, 3 tables, accepted for publication in MNRA
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