1,619 research outputs found
A note on the comparison of three near infrared reflectance spectroscopy calibration strategies for assessing herbage quality of ryegrass
peer-reviewedPerennial ryegrass (n = 1,836), Italian ryegrass (n = 137) and hybrid ryegrass (n =
103) herbage was taken from harvested plots from the Irish national variety evaluation
scheme and analysed for in vitro dry matter digestibility, water soluble carbohydrate
concentration, crude protein concentration and buffering capacity. Spectral data were
obtained using near infrared reflectance spectroscopy and three calibration strategies
(global, species-specific or local) were utilised to relate the reference values to the
spectral data. The local strategy generally provided the poorest estimation of herbage
composition, with global and species-specific calibration strategies producing similarly
accurate estimates of each quality trait. The higher accuracy and easier maintenance of
the global strategy make it the recommended calibration method for analysing quality
of ryegrass.Department of Agriculture, Food and the
Marine Research Stimulus Fund (07 526
Comparison of herbage yield, nutritive value and ensilability traits of three ryegrass species evaluated for the Irish Recommended List
peer-reviewedThis study examined 169 of the newest varieties of three ryegrass species, perennial (Lolium perenne L.), Italian (Lolium multiflorum Lam.) and hybrid (Lolium boucheanum Kunth), from Recommended List trials in Ireland. The traits examined were yield, dry matter concentration, three nutritive value traits (in vitro dry matter digestibility, water-soluble carbohydrate on a dry matter basis and crude protein concentration) and two ensilability traits (buffering capacity and water soluble carbohydrate concentration on an aqueous phase basis). Varietal monocultures of each species underwent a six cut combined simulated grazing and silage management in each of two years following sowing. Perennial ryegrass yielded less than both other species in one-year-old swards, but less than only Italian ryegrass in two-year-old swards, but generally had the higher in vitro dry matter digestibility and crude protein values. Italian ryegrass displayed the most favourable ensilability characteristics of the three species with perennial ryegrass less favourable and hybrid ryegrass intermediate. Overall, despite the high yields and favourable nutritive value and ensilability traits recorded, the general differences between the three ryegrass species studied were in line with industry expectations. These findings justify assessing the nutritive value and ensilability of ryegrass species, in addition to yield, to allow farmers select species that match farming enterprise requirements.We acknowledge the Department of Agriculture, Food and the Marine for funding provided through the Research Stimulus Fund (07 526
Detection of an Extrasolar Planet Atmosphere
We report high precision spectrophotometric observations of four planetary
transits of HD 209458, in the region of the sodium resonance doublet at 589.3
nm. We find that the photometric dimming during transit in a bandpass centered
on the sodium feature is deeper by (2.32 +/- 0.57) x 10^{-4} relative to
simultaneous observations of the transit in adjacent bands. We interpret this
additional dimming as absorption from sodium in the planetary atmosphere, as
recently predicted from several theoretical modeling efforts. Our model for a
cloudless planetary atmosphere with a solar abundance of sodium in atomic form
predicts more sodium absorption than we observe. There are several
possibilities that may account for this reduced amplitude, including reaction
of atomic sodium into molecular gases and/or condensates, photoionization of
sodium by the stellar flux, a low primordial abundance of sodium, or the
presence of clouds high in the atmosphere.Comment: 26 pages, 8 figures, accepted by ApJ 2001 November 1
An evidence-based method for targeting an abusive head trauma prevention media campaign and its evaluation
BACKGROUND: A triple-dose abusive head trauma (AHT) prevention program (Period of PURPLE Crying) was implemented. The third dose consisted of an education media campaign. The study objectives were to describe the qualitative and spatial methods developed to target AHT prevention and to evaluate this campaign.
METHODS: A questionnaire on the level of importance of factors, rated on a 7-point Likert scale, was distributed to a panel of experts to determine the best advertising locations. Ranked factors were used to create weights for statistical modeling and mapping within a Geographic Information Systems to determine optimal ad locations. The media campaign was evaluated via a telephone survey of randomly selected households.
RESULTS: The survey found locations of new families, high population density, and high percentage of lone parents to be the most important factors for selecting billboard sites. Spatial analysis revealed six areas that ranked highest in our factors. Five billboards, four media posters, and six transit shelters were selected for our advertisements. A population-based telephone survey revealed that 23% of respondents knew the campaign. Nearly half (42%) heard the radio public service announcements, and 9% saw billboards.
CONCLUSION: Extending primary prevention efforts to the public helps to create a cultural change in the way inconsolable crying, the trigger for AHT, is viewed. With the use of ranked factors and Geographic Information Systems, geographic locations with high visibility and specific risk factors for AHTwere identified for targeting the campaign, facilitating the likelihood that our message was reaching the population in greatest need
Hubble Space Telescope Transmission Spectroscopy of the Exoplanet HD 189733b: High-altitude atmospheric haze in the optical and near-UV with STIS
We present Hubble Space Telescope optical and near-ultraviolet transmission
spectra of the transiting hot-Jupiter HD189733b, taken with the repaired Space
Telescope Imaging Spectrograph (STIS) instrument. The resulting spectra cover
the range 2900-5700 Ang and reach per-exposure signal-to-noise levels greater
than 11,000 within a 500 Ang bandwidth. We used time series spectra obtained
during two transit events to determine the wavelength dependance of the
planetary radius and measure the exoplanet's atmospheric transmission spectrum
for the first time over this wavelength range. Our measurements, in conjunction
with existing HST spectra, now provide a broadband transmission spectrum
covering the full optical regime. The STIS data also shows unambiguous evidence
of a large occulted stellar spot during one of our transit events, which we use
to place constraints on the characteristics of the K dwarf's stellar spots,
estimating spot temperatures around Teff~4250 K. With contemporaneous
ground-based photometric monitoring of the stellar variability, we also measure
the correlation between the stellar activity level and transit-measured
planet-to-star radius contrast, which is in good agreement with predictions. We
find a planetary transmission spectrum in good agreement with that of Rayleigh
scattering from a high-altitude atmospheric haze as previously found from HST
ACS camera. The high-altitude haze is now found to cover the entire optical
regime and is well characterised by Rayleigh scattering. These findings suggest
that haze may be a globally dominant atmospheric feature of the planet which
would result in a high optical albedo at shorter optical wavelengths.Comment: 14 pages, 14 figures, 4 tables, accepted to MNRAS, revised version
has minor change
Photometric variability in the old open cluster M 67. II. General Survey
We use differential CCD photometry to search for variability in BVI among 990
stars projected in and around the old open cluster M 67. In a previous paper we
reported results for 22 cluster members that are optical counterparts to X-ray
sources; this study focuses on the other stars in our observations. A variety
of sampling rates were employed, allowing variability on time scales ranging
from \sim 0.3 hours to \sim 20 days to be studied. Among the brightest sources
studied, detection of variability as small as sigma approx 10 mmag is achieved
(with > 3 sigma confidence); for the typical star observed, sensitivity to
variability at levels sigma approx 20 mmag is achieved. The study is unbiased
for stars with 12.5 < B < 18.5, 12.5 < V < 18.5, and 12 < I < 18 within a
radius of about 10 arcmin from the cluster centre. In addition, stars with 10 <
BVI < 12.5 were monitored in a few small regions in the cluster. We present
photometry for all 990 sources studied, and report the variability
characteristics of those stars found to be variable at a statistically
significant level. Among the variables, we highlight several sources that merit
future study, including stars located on the cluster binary sequence, stars on
the giant branch, blue stragglers, and a newly discovered W UMa system.Comment: 12 pages, including 6 figures and 5 tables. Tables 1 and 3 only
available in electronic version of paper. Accepted by A&
Recommended from our members
Accurate detection of uniparental disomy and microdeletions by SNP array analysis in myelodysplastic syndromes with normal cytogenetics.
Progress in the management of patients with myelodysplastic syndromes (MDS) has been hampered by the inability to detect cytogenetic abnormalities in 40-60% of cases. We prospectively analyzed matched pairs of bone marrow and buccal cell (normal) DNA samples from 51 MDS patients by single nucleotide polymorphism (SNP) arrays, and identified somatically acquired clonal genomic abnormalities in 21 patients (41%). Among the 33 patients with normal bone marrow cell karyotypes, 5 (15%) had clonal, somatically acquired aberrations by SNP array analysis, including 4 with segmental uniparental disomies (UPD) and 1 with three separate microdeletions. Each abnormality was detected more readily in CD34+ cells than in unselected bone marrow cells. Paired analysis of bone marrow and buccal cell DNA from each patient was necessary to distinguish true clonal genomic abnormalities from inherited copy number variations and regions with apparent loss of heterozygosity. UPDs affecting chromosome 7q were identified in two patients who had a rapidly deteriorating clinical course despite a low-risk International Prognostic Scoring System score. Further studies of larger numbers of patients will be needed to determine whether 7q UPD detected by SNP array analysis will identify higher risk MDS patients at diagnosis, analogous to those with 7q cytogenetic abnormalities
A search for solar-like oscillations in K giants in the globular cluster M4
To expand the range in the colour-magnitude diagram where asteroseismology
can be applied, we organized a photometry campaign to find evidence for
solar-like oscillations in giant stars in the globular cluster M4. The aim was
to detect the comb-like p-mode structure characteristic for solar-like
oscillations in the amplitude spectra. The two dozen main target stars are in
the region of the bump stars and have luminosities in the range 50-140 Lsun. We
collected 6160 CCD frames and light curves for about 14000 stars were
extracted. We obtain high quality light curves for the K giants, but no clear
oscillation signal is detected. High precision differential photometry is
possible even in very crowded regions like the core of M4. Solar-like
oscillations are probably present in K giants, but the amplitudes are lower
than classical scaling laws predict.Comment: 14 pages, 16 figures, accepted for publication in A&
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