352 research outputs found
Spring wheat yield assessment under drought conditions using vegetation health index: case of Canadian prairies
Non-Peer ReviewedAgricultural drought is a major climate concern which occurs frequently on Canadian prairies. It
acts negatively on crop production, which directly affects the Canadian economy. The
Normalized Difference Vegetation Index (NDVI) has been widely used to assess crop yield
losses related to drought events. However, this index suffers from some shortcomings such as the
apparent time lag between drought impact due to rainfall deficit and NDVI response. This study
was undertaken to investigate the effectiveness of the integrated Vegetation Health Index (iVHI)
for the assessment of spring wheat yield across Canadian prairies. A time series of five years
from the Advanced Very High Resolution Radiometer (AVHRR) sensor were used to develop a
spring wheat yield model for three agroclimatic regions: subarid, semiarid and subhumid. The
results demonstrated that spring wheat yield assessment is feasible through the use of iVHI,
especially in subarid and semiarid regions where it reached a correlation coefficient of 0.75 and
0.61, respectively. This finding shows that iVHI can be used to estimate spring wheat yield losses
due to agricultural drought across the Canadian prairies. However, in subhumid regions where
spring wheat growing conditions are favourable because of adequate water supply, the integrated
NDVI (iNDVI) outperforms iVHI with a correlation coefficient of 0.44 compared to 0.34.
Consequently, to develop an efficient tool, it suggested coupling the iVHI with iNDVI to better
estimate spring wheat yield in the Canadian prairies
Effects of Hydrogen on the Phases and Transition Temperatures of NiTi
Austenitic (B2) NiTi samples were cathodically charged with various amounts of hydrogen. Trends are tracked based on temperature, time and voltage throughout the process to establish consistent and predictive hydrogen charging procedures. The effect of hydrogen on the austenitic structure and the formation of hydrides are studied with x-ray diffraction (XRD). An increase in the austenite lattice parameter with increased hydrogen content is observed up to a hydrogen solubility limit of approximately 85 wppm. At greater hydrogen concentrations, additional XRD peaks appear, suggesting possible hydride formation. Differential scanning calorimetry (DSC) results show a decrease in both the austenitic and martensitic transition temperatures with increased atomic hydrogen content and increased hydride phase. Scanning electron microscopy (SEM) is used to reveal the hydride phase. The effect of atomic hydrogen on NiTi and the structure of the hydride phase are compared with previous hydrogen studies
Using Technology in Reggio-Inspired Long-Term Projects
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42648/1/10643_2004_Article_290536.pd
A prospective cohort study assessing clinical referral management & workforce allocation within a UK regional medical genetics service
Abstract
Ensuring patient access to genomic information in the face of increasing demand requires clinicians to develop innovative ways of working. This paper presents the first empirical prospective observational cohort study of UK multi-disciplinary genetic service delivery. It describes and explores collaborative working practices including the utilisation and role of clinical geneticists and non-medical genetic counsellors. Six hundred and fifty new patients referred to a regional genetics service were tracked through 850 clinical contacts until discharge. Referral decisions regarding allocation of lead health professional assigned to the case were monitored, including the use of initial clinical contact guidelines. Significant differences were found in the cases led by genetic counsellors and those led by clinical geneticists. Around a sixth, 16.8% (109/650) of referrals were dealt with by a letter back to the referrer or re-directed to another service provider and 14.8% (80/541) of the remaining patients chose not to schedule an appointment. Of the remaining 461 patients, genetic counsellors were allocated as lead health professional for 46.2% (213/461). A further 61 patients did not attend. Of those who did, 86% (345/400) were discharged after one or two appointments. Genetic counsellors contributed to 95% (784/825) of total patient contacts. They provided 93.7% (395/432) of initial contacts and 26.8% (106/395) of patients were discharged at that point. The information from this study informed a planned service re-design. More research is needed to assess the effectiveness and efficiency of different models of collaborative multi-disciplinary working within genetics services. Keywords (MeSH terms)
Genetic Services, Genetic Counseling, Interdisciplinary Communication, Cohort Studies, Delivery of Healthcare, Referral and Consultation
Polymorphisms in the carcinogen detoxification genes CYB5A and CYB5R3 and breast cancer risk in African American women
Cytochrome b5 (encoded by CYB5A) and NADH cytochrome b5 reductase (encoded by CYB5R3) detoxify aromatic and heterocyclic amine mammary carcinogens found in cigarette smoke. We hypothesized that CYB5A and CYB5R3 polymorphisms would be associated with breast cancer risk in women
International Veterinary Epilepsy Task Force consensus proposal: Medical treatment of canine epilepsy in Europe
In Europe, the number of antiepileptic drugs (AEDs) licensed for dogs has grown considerably over the last years. Nevertheless, the same questions remain, which include, 1) when to start treatment, 2) which drug is best used initially, 3) which adjunctive AED can be advised if treatment with the initial drug is unsatisfactory, and 4) when treatment changes should be considered. In this consensus proposal, an overview is given on the aim of AED treatment, when to start long-term treatment in canine epilepsy and which veterinary AEDs are currently in use for dogs. The consensus proposal for drug treatment protocols, 1) is based on current published evidence-based literature, 2) considers the current legal framework of the cascade regulation for the prescription of veterinary drugs in Europe, and 3) reflects the authors’ experience. With this paper it is aimed to provide a consensus for the management of canine idiopathic epilepsy. Furthermore, for the management of structural epilepsy AEDs are inevitable in addition to treating the underlying cause, if possible
Gamma Ray Flashes Produced by Lightning Observed at Ground Level by TETRA-II
In its first 2 years of operation, the ground-based Terrestrial gamma ray
flash and Energetic Thunderstorm Rooftop Array(TETRA)-II array of gamma ray
detectors has recorded 22 bursts of gamma rays of millisecond-scale duration
associated with lightning. In this study, we present the TETRA-II observations
detected at the three TETRA-II ground-level sites in Louisiana, Puerto Rico,
and Panama together with the simultaneous radio frequency signals from the
VAISALA Global Lightning Data set, VAISALA National Lightning Detection
Network, Earth Networks Total Lightning Network, and World Wide Lightning
Location Network. The relative timing between the gamma ray events and the
lightning activity is a key parameter for understanding the production
mechanism(s) of the bursts. The gamma ray time profiles and their correlation
with radio sferics suggest that the gamma ray events are initiated by lightning
leader activity and are produced near the last stage of lightning leader
channel development prior to the lightning return stroke.Comment: 10 pages, 9 figure
Gamma-ray Observations Under Bright Moonlight with VERITAS
Imaging atmospheric Cherenkov telescopes (IACTs) are equipped with sensitive
photomultiplier tube (PMT) cameras. Exposure to high levels of background
illumination degrades the efficiency of and potentially destroys these
photo-detectors over time, so IACTs cannot be operated in the same
configuration in the presence of bright moonlight as under dark skies. Since
September 2012, observations have been carried out with the VERITAS IACTs under
bright moonlight (defined as about three times the night-sky-background (NSB)
of a dark extragalactic field, typically occurring when Moon illumination >
35%) in two observing modes, firstly by reducing the voltage applied to the
PMTs and, secondly, with the addition of ultra-violet (UV) bandpass filters to
the cameras. This has allowed observations at up to about 30 times previous NSB
levels (around 80% Moon illumination), resulting in 30% more observing time
between the two modes over the course of a year. These additional observations
have already allowed for the detection of a flare from the 1ES 1727+502 and for
an observing program targeting a measurement of the cosmic-ray positron
fraction. We provide details of these new observing modes and their performance
relative to the standard VERITAS observations
Dark Matter Constraints from a Joint Analysis of Dwarf Spheroidal Galaxy Observations with VERITAS
We present constraints on the annihilation cross section of WIMP dark matter
based on the joint statistical analysis of four dwarf galaxies with VERITAS.
These results are derived from an optimized photon weighting statistical
technique that improves on standard imaging atmospheric Cherenkov telescope
(IACT) analyses by utilizing the spectral and spatial properties of individual
photon events. We report on the results of 230 hours of observations of
five dwarf galaxies and the joint statistical analysis of four of the dwarf
galaxies. We find no evidence of gamma-ray emission from any individual dwarf
nor in the joint analysis. The derived upper limit on the dark matter
annihilation cross section from the joint analysis is at 1 TeV for the bottom quark () final state,
at 1 TeV for the tau lepton
() final state and at 1 TeV for the gauge boson () final state.Comment: 14 pages, 9 figures, published in PRD, Ascii tables containing
annihilation cross sections limits are available for download as ancillary
files with readme.txt file description of limit
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