350 research outputs found
The relationship between various live animal scores/measurements and carcass classification for conformation and fatness with meat yield and distribution, and ultimate carcass value
End of project reportAccordingly, the primary objectives of the following study were to:
(1) determine the relationship of live animal muscular and skeletal scores, ultrasonically scanned muscle
and fat depth measurements of the m. longissimus dorsi, and carcass conformation and fat scores with
kill-out proportion, carcass composition and value.
(2) Specifically develop and test the accuracy of prediction equations for carcass meat, fat and bone
proportions, derived from carcass conformation and fat scores, and develop prediction equations for
total carcass composition from hind-quarter composition
Testing stellar population synthesis models with Sloan Digital Sky Survey colors of M31's globular clusters
Accurate stellar population synthesis models are vital in understanding the
properties and formation histories of galaxies. In order to calibrate and test
the reliability of these models, they are often compared with observations of
star clusters. However, relatively little work has compared these models in the
ugriz filters, despite the recent widespread use of this filter set. In this
paper, we compare the integrated colors of globular clusters in the Sloan
Digital Sky Survey (SDSS) with those predicted from commonly used simple
stellar population (SSP) models. The colors are based on SDSS observations of
M31's clusters and provide the largest population of star clusters with
accurate photometry available from the survey. As such, it is a unique sample
with which to compare SSP models with SDSS observations. From this work, we
identify a significant offset between the SSP models and the clusters' g-r
colors, with the models predicting colors which are too red by g-r\sim0.1. This
finding is consistent with previous observations of luminous red galaxies in
the SDSS, which show a similar discrepancy. The identification of this offset
in globular clusters suggests that it is very unlikely to be due to a minority
population of young stars. The recently updated SSP model of Maraston &
Stromback better represents the observed g-r colors. This model is based on the
empirical MILES stellar library, rather than theoretical libraries, suggesting
an explanation for the g-r discrepancy.Comment: 8 pages, 4 figures, accepted for publication in Ap
Manipulation of drugs to achieve the required dose is intrinsic to paediatric practice but is not supported by guidelines or evidence
Background: A lack of age-appropriate formulations can make it difficult to administer medicines to children. A manipulation of the dosage form may be required to achieve the required dose. This study aimed to describe medicines that are manipulated to achieve the required dose in paediatric practice.Method: A structured, undisguised observational study and postal survey. The observational study investigated drug manipulations occurring in clinical practice across three sites. The questionnaire, administered to a sample of paediatric nurses throughout the UK, surveyed manipulations conducted and nurses' experiences and views.Results: The observational study identified 310 manipulations, of which 62% involved tablets, 21% were intravenous drugs and 10% were sachets. Of the 54 observed manipulations 40 involved tablets with 65% of the tablets being cut and 30% dispersed to obtain a smaller dose. 188 manipulations were reported by questionnaire respondents, of these 46% involved tablets, 12% were intravenous drugs, and 12% were nebuliser solutions. Manipulations were predominantly, but not exclusively, identified in specialist clinical areas with more highly dependent patients. Questionnaire respondents were concerned about the accuracy of the dose achieved following manipulations and the lack of practice guidance.Conclusion: Manipulations to achieve the required dose occur throughout paediatric in-patient settings. The impact of manipulations on the efficacy of the drugs, the accuracy of the dose and any adverse effects on patients is not known. There is a need to develop evidence-based guidance for manipulations of medicines in children
A Surprisingly High Pair Fraction for Extremely Massive Galaxies at z ~ 3 in the GOODS NICMOS Survey
We calculate the major pair fraction and derive the major merger fraction and
rate for 82 massive () galaxies at
utilising deep HST NICMOS data taken in the GOODS North and South fields. For
the first time, our NICMOS data provides imaging with sufficient angular
resolution and depth to collate a sufficiently large sample of massive galaxies
at z 1.5 to reliably measure their pair fraction history. We find strong
evidence that the pair fraction of massive galaxies evolves with redshift. We
calculate a pair fraction of = 0.29 +/- 0.06 for our whole sample at
. Specifically, we fit a power law function of the form
to a combined sample of low redshift data from Conselice
et al. (2007) and recently acquired high redshift data from the GOODS NICMOS
Survey. We find a best fit to the free parameters of = 0.008 +/- 0.003
and = 3.0 +/- 0.4. We go on to fit a theoretically motivated
Press-Schechter curve to this data. This Press-Schechter fit, and the data,
show no sign of levelling off or turning over, implying that the merger
fraction of massive galaxies continues to rise with redshift out to z 3.
Since previous work has established that the merger fraction for lower mass
galaxies turns over at z 1.5 - 2.0, this is evidence that higher mass
galaxies experience more mergers earlier than their lower mass counterparts,
i.e. a galaxy assembly downsizing. Finally, we calculate a merger rate at z =
2.6 of 5 10 Gpc Gyr, which experiences
no significant change to 1.2 10 Gpc Gyr
at z = 0.5. This corresponds to an average galaxy
experiencing 1.7 +/- 0.5 mergers between z = 3 and z = 0.Comment: 5 pages, 3 figures, accepted to MNRA
Back-illuminated electron multiplying technology: The world's most sensitive CCD for ultra low-light microscopy
ABSTRACT The back-illuminated Electron Multiplying Charge Coupled Device (EMCCD) camera stands to be one the most revolutionary contributions ever to the burgeoning fields of low-light dynamic cellular microscopy and single molecule detection, combining extremely high photon conversion efficiency with the ability to eliminate the readout noise detection limit. Here, we present some preliminary measurements recorded by a very rapid frame rate version of this camera technology, incorporated into a spinning disk confocal microscopy set-up that is used for fast intracellular calcium flux measurements. The results presented demonstrate the united effects of: (a) EMCCD technology in amplifying the very weak signal from these fluorescently labelled cells above the readout noise detection limit, that they would otherwise be completely lost in; (b) back-thinned CCD technology in maximizing the signal/shot noise ratio from such weak photon fluxes. It has also been shown how this innovative development can offer significant signal improvements over that afforded by ICCD technology. Practically, this marked advancement in detector sensitivity affords benefits such as shorter exposure times (therefore faster frame rates), lower dye concentrations and reduced excitation powers and will remove some of the barriers that have been restricting the development of new innovative low-light microscopy techniques
Assembly of the Red Sequence in Infrared-Selected Galaxy Clusters from the IRAC Shallow Cluster Survey
We present results for the assembly and star formation histories of massive
(~L*) red sequence galaxies in 11 spectroscopically confirmed,
infrared-selected galaxy clusters at 1.0 < z < 1.5, the precursors to
present-day massive clusters with M ~ 10^15 M_sun. Using rest-frame optical
photometry, we investigate evolution in the color and scatter of the red
sequence galaxy population, comparing with models of possible star formation
histories. In contrast to studies of central cluster galaxies at lower redshift
(z < 1), these data are clearly inconsistent with the continued evolution of
stars formed and assembled primarily at a single, much-earlier time.
Specifically, we find that the colors of massive cluster galaxies at z = 1.5
imply that the bulk of star formation occurred at z ~ 3, whereas by z = 1 their
colors imply formation at z ~ 2; therefore these galaxies exhibit approximately
the same luminosity-weighted stellar age at 1 < z < 1.5. This likely reflects
star formation that occurs over an extended period, the effects of significant
progenitor bias, or both. Our results generally indicate that massive cluster
galaxy populations began forming a significant mass of stars at z >~ 4,
contained some red spheroids by z ~ 1.5, and were actively assembling much of
their final mass during 1 < z < 2 in the form of younger stars. Qualitatively,
the slopes of the cluster color-magnitude relations are consistent with no
significant evolution relative to local clusters.Comment: 24 pages, 9 figures, accepted to Ap
Wearable wireless inertial measurement for sports applications
The advent of MEMS inertial sensors has reduced the size, cost and power requirements of 6 Degrees-of-Freedom inertial measurement systems to a level where their use can be considered for wearable wireless monitoring devices. Many applications for such Wearable Wireless Inertial Measurement Units exist in the area of sports and sports science. Such a system would be critical in providing data for the analysis of the kinematic motion data of an athlete - to characterise a player’s technique or track progress and provide accurate,
quantitative feedback to player and coach in near real time. A small, lightweight and low power device with the ability to sense the full range of human motion at a high sampling rate is required for such applications. It must also be robust, well sealed and comfortable to wear. Further development and miniaturisation of such devices coupled with progress in
energy scavenging may lead to their use in other areas and their near ubiquity, with the potential to be embedded within clothes, buildings, materials, objects and people for health monitoring, location tracking and other purpose
The Average Physical Properties and Star Formation Histories of the UV-Brightest Star-Forming Galaxies at z~3.7
[Abridged] We investigate the average physical properties and star formation
histories of the most UV-luminous star-forming galaxies at z~3.7. Our results
are derived from analyses of the average spectral energy distributions (SEDs),
constructed from stacked optical to infrared photometry, of a sample of the
1,902 most UV-luminous star-forming galaxies found in 5.3 square degrees of the
NOAO Deep Wide-Field Survey. We bin the sample according to UV luminosity, and
find that the shape of the average SED in the rest-frame optical and infrared
is fairly constant with UV luminosity: i.e., more UV luminous galaxies are, on
average, also more luminous at longer wavelengths. In the rest-UV, however, the
spectral slope (measured at 0.13-0.28 um) rises steeply with the median UV
luminosity from -1.8 at L L* to -1.2 in the brightest bin (L~4-5L*). We use
population synthesis analyses to derive the average physical properties of
these galaxies and find that: (1) L_UV, and thus star formation rates (SFRs),
scale closely with stellar mass such that more UV-luminous galaxies are also
more massive; (2) The median ages indicate that the stellar populations are
relatively young (200-400 Myr) and show little correlation with UV luminosity;
and (3) More UV-luminous galaxies are dustier than their less-luminous
counterparts, such that L~4-5L* galaxies are extincted up to A(1600)=2 mag
while L L* galaxies have A(1600)=0.7-1.5 mag. Based on these observations, we
argue that the average star formation histories of UV-luminous galaxies are
better described by models in which SFR increases with time in order to
simultaneously reproduce the tight correlation between the observed SFR and
stellar mass, and the universally young ages of these galaxies. We demonstrate
the potential of measurements of the SFR-M* relation at multiple redshifts to
discriminate between simple models of star formation histories.Comment: 14 pages, 7 figures. Accepted for publication in Astrophysical
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