66 research outputs found
Estimating the economic impacts of bird and rodent damage to selected California crops
2011 Spring.Includes bibliographical references.This research estimates the direct financial costs and the changes in economic welfare associated with bird and rodent damage to 15 different crop markets in eight agricultural regions in California. Three different models are used to quantify this impact: a meta-analysis to aggregate and analysis a large database of 206 damage estimates from 43 studies related to 15 crops across 6 (of 8) regions of California, a direct financial cost model to identify changes in profits and costs from an individual producer's perspective, and a combination of an equilibrium displacement model (EDM) and an economic surplus model to estimate changes to producer and consumer surpluses. Using a range of damage estimates calculated from the meta-analysis, results from the direct financial analysis indicate that birds and rodents have a direct financial impact in reducing income from lower production and increasing production costs and was calculated as a range from 1,726 m. Results from the EDM and economic surplus model are the estimated gain in consumer surplus resulting from an absence of bird and rodent damage and a reduction is between 396.0 m and $658.8 m. Understanding the aggregate impact of damage caused by birds and rodents to multiple economically important crops in California agriculture is crucial. The results of this study indicate that bird and rodent have caused negative impacts on California producers and consumers. Through the inclusion of a more complete damage data set, the impact of this damage on profits and consumer and producer surpluses was estimated with greater accuracy and yielded predictive and interpretive value to the profession
Inoculation of Weaned Pigs by Feed, Water, and Airborne Transmission of Salmonella enterica Serotype 4,[5],12:i:-
Salmonella enterica serotype 4,[5],12:i:- (STM) has become an increasing problem for food safety and has been often detected in pork products. For this study, weanling pigs were exposed to STM-contaminated feed, water, or air to determine possible STM transmission routes. An uninoculated control group of pigs was included. The STM was monitored daily in feces and rectal and nasal swabs. The STM colonization was most prevalent in tissues from tonsil, lower intestine, and mesenteric lymph nodes. No differences in lesion severity were observed between inoculated and control pigs. Contaminated feed, water, and aerosolized particles caused infection in weaned pigs; however, no STM colonization was observed in skeletal muscle destined for human consumption. Based on the results from this study, STM contamination in pork products most likely results from cross-contamination of meat by digesta or lymph node tissue during processing
Inoculation of Weaned Pigs by Feed, Water, and Airborne Transmission of Salmonella enterica Serotype 4,[5],12:i:-
Salmonella enterica serotype 4,[5],12:i:- (STM) has become an increasing problem for food safety and has been often detected in pork products. For this study, weanling pigs were exposed to STM-contaminated feed, water, or air to determine possible STM transmission routes. An uninoculated control group of pigs was included. The STM was monitored daily in feces and rectal and nasal swabs. The STM colonization was most prevalent in tissues from tonsil, lower intestine, and mesenteric lymph nodes. No differences in lesion severity were observed between inoculated and control pigs. Contaminated feed, water, and aerosolized particles caused infection in weaned pigs; however, no STM colonization was observed in skeletal muscle destined for human consumption. Based on the results from this study, STM contamination in pork products most likely results from cross-contamination of meat by digesta or lymph node tissue during processing
The DEEP2 Galaxy Redshift Survey: Design, Observations, Data Reduction, and Redshifts
We describe the design and data sample from the DEEP2 Galaxy Redshift Survey,
the densest and largest precision-redshift survey of galaxies at z ~ 1
completed to date. The survey has conducted a comprehensive census of massive
galaxies, their properties, environments, and large-scale structure down to
absolute magnitude M_B = -20 at z ~ 1 via ~90 nights of observation on the
DEIMOS spectrograph at Keck Observatory. DEEP2 covers an area of 2.8 deg^2
divided into four separate fields, observed to a limiting apparent magnitude of
R_AB=24.1. Objects with z < 0.7 are rejected based on BRI photometry in three
of the four DEEP2 fields, allowing galaxies with z > 0.7 to be targeted ~2.5
times more efficiently than in a purely magnitude-limited sample. Approximately
sixty percent of eligible targets are chosen for spectroscopy, yielding nearly
53,000 spectra and more than 38,000 reliable redshift measurements. Most of the
targets which fail to yield secure redshifts are blue objects that lie beyond z
~ 1.45. The DEIMOS 1200-line/mm grating used for the survey delivers high
spectral resolution (R~6000), accurate and secure redshifts, and unique
internal kinematic information. Extensive ancillary data are available in the
DEEP2 fields, particularly in the Extended Groth Strip, which has evolved into
one of the richest multiwavelength regions on the sky. DEEP2 surpasses other
deep precision-redshift surveys at z ~ 1 in terms of galaxy numbers, redshift
accuracy, sample number density, and amount of spectral information. We also
provide an overview of the scientific highlights of the DEEP2 survey thus far.
This paper is intended as a handbook for users of the DEEP2 Data Release 4,
which includes all DEEP2 spectra and redshifts, as well as for the
publicly-available DEEP2 DEIMOS data reduction pipelines. [Abridged]Comment: submitted to ApJS; data products available for download at
http://deep.berkeley.edu/DR4
Pre-ART Levels of Inflammation and Coagulation Markers Are Strong Predictors of Death in a South African Cohort with Advanced HIV Disease
BACKGROUND: Levels of high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), and D-dimer predict mortality in HIV patients on antiretroviral therapy (ART) with relatively preserved CD4+ T cell counts. We hypothesized that elevated pre-ART levels of these markers among patients with advanced HIV would be associated with an increased risk of death following the initiation of ART. METHODS: Pre-ART plasma from patients with advanced HIV in South Africa was used to measure hsCRP, IL-6 and D-dimer. Using a nested case-control study design, the biomarkers were measured for 187 deaths and two controls matched on age, sex, clinical site, follow-up time and CD4+ cell counts. Odds ratios were estimated using conditional logistic regression. In addition, for a random sample of 100 patients, biomarkers were measured at baseline and 6 months following randomization to determine whether ART altered their levels. RESULTS: Median baseline biomarkers levels for cases and controls, respectively, were 11.25 vs. 3.6 mg/L for hsCRP, 1.41 vs. 0.98 mg/L for D-dimer, and 9.02 vs. 4.20 pg/mL for IL-6 (all p<0.0001). Adjusted odds ratios for the highest versus lowest quartile of baseline biomarker levels were 3.5 (95% CI: 1.9-6.7) for hsCRP, 2.6 (95%CI 1.4-4.9) for D-dimer, and 3.8 (95% CI: 1.8-7.8) for IL-6. These associations were stronger for deaths that occurred more proximal to the biomarker measurements. Levels of D-dimer and IL-6, but not hsCRP, were significantly lower at month 6 after commencing ART compared to baseline (p<0.0001). CONCLUSIONS: Among patients with advanced HIV disease, elevated pre-ART levels of hsCRP, IL-6 and D-dimer are strongly associated with early mortality after commencing ART. Elevated levels of inflammatory and coagulation biomarkers may identify patients who may benefit from aggressive clinical monitoring after commencing ART. Further investigation of strategies to reduce biomarkers of inflammation and coagulation in patients with advanced HIV disease is warranted. TRIAL REGISTRATION: Parent study: ClinicalTrials.gov NCT00342355
Luminous Thermal Flares from Quiescent Supermassive Black Holes
A dormant supermassive black hole lurking in the center of a galaxy will be
revealed when a star passes close enough to be torn apart by tidal forces, and
a flare of electromagnetic radiation is emitted when the bound fraction of the
stellar debris falls back onto the black hole and is accreted. Here we present
the third candidate tidal disruption event discovered in the GALEX Deep Imaging
Survey: a 1.6x10^{43} erg s^{-1} UV/optical flare from a star-forming galaxy at
z=0.1855. The UV/optical SED during the peak of the flare measured by GALEX and
Palomar LFC imaging can be modeled as a single temperature blackbody with
T_{bb}=1.7x10^{5} K and a bolometric luminosity of 3x10^{45} erg s^{-1},
assuming an internal extinction with E(B-V)_{gas}=0.3. The Chandra upper limit
on the X-ray luminosity during the peak of the flare, L_{X}(2-10 keV)< 10^{41}
erg s^{-1}, is 2 orders of magnitude fainter than expected from the ratios of
UV to X-ray flux density observed in active galaxies. We compare the light
curves and broadband properties of all three tidal disruption candidates
discovered by GALEX, and find that (1) the light curves are well fitted by the
power-law decline expected for the fallback of debris from a tidally disrupted
solar-type star, and (2) the UV/optical SEDs can be attributed to thermal
emission from an envelope of debris located at roughly 10 times the tidal
disruption radius of a ~10^{7} M_sun central black hole. We use the observed
peak absolute optical magnitudes of the flares (-17.5 > M_{g} > -18.9) to
predict the detection capabilities of upcoming optical synoptic surveys.
(Abridged)Comment: Accepted for Publication in ApJ, 19 pages, 10 figures, 2 tables,
emulateapj, corrections from proofs adde
Suppression of star formation in early-type galaxies by feedback from supermassive black holes
Detailed high-resolution observations of the innermost regions of nearby
galaxies have revealed the presence of supermassive black holes1. These black
holes may interact with their host galaxies by means of 'feedback' in the form
of energy and material jets; this feedback affects the evolution of the host
and gives rise to observed relations between the black hole and the host. Here
we report observations of the ultraviolet emissions of massive early-type
galaxies. We derive an empirical relation for a critical black-hole mass (as a
function of velocity dispersion) above which the outflows from these black
holes suppress star formation in their hosts by heating and expelling all
available cold gas. Supermassive black holes are negligible in mass compared to
their hosts but nevertheless seem to play a critical role in the star formation
history of galaxies.Comment: Nature, in press. 27 pages, 4 Figures. Article & supplements with
high-resolution figures can be downloaded at:
http://www-astro.physics.ox.ac.uk/~kevins/PAPERS/AGN_feedback.pd
The Host Galaxies of AGN
We examine the properties of the host galaxies of 22,623 narrow-line AGN with
0.02<z<0.3 selected from a complete sample of 122,808 galaxies from the Sloan
Digital Sky Survey. We focus on the luminosity of the [OIII]5007
emission line as a tracer of the strength of activity in the nucleus. We study
how AGN host properties compare to those of normal galaxies and how they depend
on L[OIII]. We find that AGN of all luminosities reside almost exclusively in
massive galaxies and have distributions of sizes, stellar surface mass
densities and concentrations that are similar to those of ordinary early-type
galaxies in our sample. The host galaxies of low-luminosity AGN have stellar
populations similar to normal early-types. The hosts of high- luminosity AGN
have much younger mean stellar ages. The young stars are not preferentially
located near the nucleus of the galaxy, but are spread out over scales of at
least several kiloparsecs. A significant fraction of high- luminosity AGN have
strong H absorption-line equivalent widths, indicating that they
experienced a burst of star formation in the recent past. We have also examined
the stellar populations of the host galaxies of a sample of broad-line AGN. We
conclude that there is no significant difference in stellar content between
type 2 Seyfert hosts and QSOs with the same [OIII] luminosity and redshift.
This establishes that a young stellar population is a general property of AGN
with high [OIII] luminosities.Comment: submitted to MNRAS, 44 pages, version with full resolution figures
available at http://www.mpa-garching.mpg.de/~gamk/agnpaper/agnpaper.p
Optical Trapping with High Forces Reveals Unexpected Behaviors of Prion Fibrils
Amyloid fibrils are important in diverse cellular functions, feature in many human diseases and have potential applications in nanotechnology. Here we describe methods that combine optical trapping and fluorescent imaging to characterize the forces that govern the integrity of amyloid fibrils formed by a yeast prion protein. A crucial advance was to use the self-templating properties of amyloidogenic proteins to tether prion fibrils, enabling their manipulation in the optical trap. At normal pulling forces the fibrils were impervious to disruption. At much higher forces (up to 250 pN), discontinuities occurred in force-extension traces before fibril rupture. Experiments with selective amyloid-disrupting agents and mutations demonstrated that such discontinuities were caused by the unfolding of individual subdomains. Thus, our results reveal unusually strong noncovalent intermolecular contacts that maintain fibril integrity even when individual monomers partially unfold and extend fibril length.National Institutes of Health (U.S.) (Grant GM025874)National Science Foundation (U.S.). CAREER (Award 0643745
The effects of health value on healthful food selection intention at restaurants: Considering the role of attitudes toward taste and healthfulness of healthful foods
This study investigated restaurant customers’ intent to choose healthful (e.g., low-fat or low-calorie) menu items using the value–attitude–behavior model. The sample was comprised of customers who had previously consumed these types of healthful items at a casual dining restaurant. Structural equation modeling was used to analyze data. Results revealed that customers’ health values had a positive effect on attitudes and behavioral intentions and that customers’ attitudes toward low-fat or low-calorie menu items positively influenced behavioral intentions. However, attitudes toward taste of healthful menu items exerted a greater impact on behavioral intentions to choose, recommend, and spread a positive word-of-mouth about those menu items. To meet customers’ desire, restaurants should continue to focus on great-tasting healthful foods
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