281 research outputs found
Plant height and hydraulic vulnerability to drought and cold
Understanding how plants survive drought and cold is increasingly important as plants worldwide experience dieback with drought in moist places and grow taller with warming in cold ones. Crucial in plant climate adaptation are the diameters of water-transporting conduits. Sampling 537 species across climate zones dominated by angiosperms, we find that plant size is unambiguously the main driver of conduit diameter variation. And because taller plants have wider conduits, and wider conduits within species are more vulnerable to conduction-blocking embolisms, taller conspecifics should be more vulnerable than shorter ones, a prediction we confirm with a plantation experiment. As a result, maximum plant size should be short under drought and cold, which cause embolism, or increase if these pressures relax. That conduit diameter and embolism vulnerability are inseparably related to plant size helps explain why factors that interact with conduit diameter, such as drought or warming, are altering plant heights worldwide
Meat tenderness genetic polymorphisms occurrence and distribution in five Zebu breeds in Mexico
Background: The Zebu cattle are represented by a diverse group of
breeds in M\ue9xico. Traditionally these breeds have been associated
with the tough beef characteristic. Validated genetic markers have the
potential to be included in marker-assisted selection and management
programs in order to improve traits such as beef tenderness. The
incidence and distribution of Calpain and Calpastatin polymorphisms
strongly associated with beef tenderness were estimated in registered
cattle of five Zebu breeds in Mexico. Results: A low and in some
cases null frequency of favorable C allele of CAPN316 was determined in
all breeds. Conversely, a more equilibrated frequency in CAPN4751 and
CAST loci was observed. Conclusions: Although the relatively low
occurrence of favorable alleles in assessed loci may limit their use in
selection programs, genotyping availability might be a practical and
comprehensive tool for introgression programs by marker assisted
selection and management as to improve meat tenderness of Zebu breeds
Convenient genotyping of nine bovine K-casein variants
K-casein gene polymorphisms are of major importance in the dairy
industry due to their association with different quality and productive
traits (i.e., milk protein). Several methods for genotyping this gene
have been proposed; however, none are focused on the simultaneous
discrimination of nine K-casein variants. A strategy based on PCR-RFLP
was designed to characterize nine K-casein variants (A, B, C, E, F2, G,
H, I and J) and used to genotype three cattle populations: Gyrholando
(3/8 Gyr x 5/8 Holstein), Charolais and Carora. The B variant was the
most frequent in the Charolais and Carora breeds, with allelic
frequencies of 0.60 and 0.59, respectively. In the Gyrholando breed,
four variants were found, with the A variant being the most frequent
and E and H the least. The genotyping strategy was effective in
detection and differentiation of K-casein variants, and it is proposed
for use in laboratories with minimal molecular biology equipment for
genotyping and evaluation of the phenotypic effects of nine K-casein
variants on milk production and quality
Geographical variation in therapy for bloodstream infections due to multidrug-resistant enterobacteriaceae: a post hoc analysis of the INCREMENT study
We aimed to describe regional differences in therapy for bloodstream infection (BSI) caused by extended-spectrum ?-lactamase-producing Enterobacteriaceae (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE). 1,482 patients in 12 countries were included from an observational study of BSI caused by ESBL-E or CPE. Multivariate logistic regression was used to calculate adjusted odds ratios (aORs) for the influence of country of recruitment on empirical use of ?-lactam/?-lactamase inhibitors (BLBLI) or carbapenems, targeted use of BLBLI for ESBL-E and use of targeted combination therapy for CPE. The use of BLBLI for empirical therapy was least likely in sites from Israel (aOR 0.34, 95% CI 0.14-0.81), Greece (aOR 0.49, 95% CI 0.26-0.94) and Canada (aOR 0.31, 95% CI 0.11-0.88) but more likely in Italy (aOR 1.58, 95% CI 1.11-2.2) and Turkey (aOR 2.09, 95% CI 1.14-3.81), compared to Spain as a reference. Empirical carbapenems were more likely to be used in sites from Taiwan (aOR 1.73, 95% CI 1.03-2.92) and USA (aOR 1.89; 95% CI 1.05-3.39), and less likely in Italy (aOR 0.44, 95% CI 0.28-0.69) and Canada (aOR 0.10, 95% CI 0.01-0.74). Targeted BLBLI for ESBL-E was more likely in sites from Italy. Treatment at sites within Israel, Taiwan, Turkey and Brazil was associated with less combination therapy for CPE. Although this study does not provide precise data on the relative prevalence of ESBL-E or CPE, significant variation in therapy exists across countries even after adjustment for patient factors. A better understanding of what influences therapeutic choices for these infections will aid antimicrobial stewardship efforts.PH is supported by an Australian Postgraduate Award from the University of
Queensland. The study was funded by the Ministerio de Economía y Competitividad,
Instituto de Salud Carlos III - co-financed by European Development Regional Fund "A way to
achieve Europe" ERDF, Spanish Network for the Research in Infectious Diseases (REIPI
RD12/0015). BGG, JRB, APH and YC also received funds from the COMBACTE-CARE
project (grant agreement 115620), Innovative Medicines Initiative (IMI), the European
Union's Seventh Framework Programme (FP7/2007-2013) and in-kind contributions from
EFPIA companies
Observation and Mass Measurement of the Baryon
We report the observation and measurement of the mass of the bottom, strange
baryon through the decay chain , where
, , and .
Evidence for observation is based on a signal whose probability of arising from
the estimated background is 6.6 x 10^{-15}, or 7.7 Gaussian standard
deviations. The mass is measured to be (stat.) (syst.) MeV/.Comment: Minor text changes for the second version. Accepted by Phys. Rev.
Let
Search for New Particles Leading to Z+jets Final States in Collisions at TeV
We present the results of a search for new particles that lead to a \Z boson
plus jets in collisions at TeV using the Collider
Detector at Fermilab (CDF II). A data sample with a luminosity of 1.06 \ifb\
collected using \Z boson decays to and is used. We describe a
completely data-based method to predict the dominant background from
standard-model \Z+jet events. This method can be similarly applied to other
analyses requiring background predictions in multi-jet environments, as shown
when validating the method by predicting the background from +jets in \ttbar
production. No significant excess above the background prediction is observed,
and a limit is set using a fourth generation quark model to quantify the
acceptance. Assuming and using a leading-order
calculation of the cross section, quark masses below 268 \gev/c^2
are excluded at 95% confidence level.Comment: To be submitted to PR
First Measurement of the W Boson Mass in Run II of the Tevatron
We present a measurement of the W boson mass using 200/pb of data collected
in pbar p collisions at sqrt(s) = 1.96 TeV by the CDF II detector at Run II of
the Fermilab Tevatron. With a sample of 63964 W -> e nu candidates and 51128 W
-> mu nu candidates, we measure M_W = (80413 +- 34 (stat) +- 34 (syst) = 80413
+- 48) MeV/c^2. This is the most precise single measurement of the W boson mass
to date.Comment: published version in PR
Polarizations of J/psi and psi(2S) Mesons Produced in ppbar Collisions at 1.96 TeV
We have measured the polarizations of \jpsi and \psiprime mesons as
functions of their transverse momentum \pt when they are produced promptly in
the rapidity range with \pt \geq 5 \pgev. The analysis is performed
using a data sample with an integrated luminosity of about 800 \ipb collected
by the CDF II detector. For both vector mesons, we find that the polarizations
become increasingly longitudinal as \pt increases from 5 to 30 \pgev. These
results are compared to the predictions of nonrelativistic quantum
chromodynamics and other contemporary models. The effective polarizations of
\jpsi and \psiprime mesons from -hadron decays are also reported.Comment: 8 pages, 7 figures, published in Physical Review Letter
Precise measurement of the top quark mass in the lepton+jets topology at CDF II
We present a measurement of the mass of the top quark from proton-antiproton
collisions recorded at the CDF experiment in Run II of the Fermilab Tevatron.
We analyze events from the single lepton plus jets final state (). The top quark mass is extracted
using a direct calculation of the probability density that each event
corresponds to the final state. The probability is a function of both
the mass of the top quark and the energy scale of the calorimeter jets, which
is constrained {\it in situ} by the hadronic boson mass. Using 167 events
observed in 955 pb of integrated luminosity, we achieve the single
most precise measurement of the top quark mass, 170.8 2.2 (stat.)
1.4 (syst.) GeV/.Comment: accepted by Phys. Rev. Let
Search for resonant ttbar production in ppbar collisions at sqrt{s}=1.96 TeV
We report on a search for narrow-width particles decaying to a top and
antitop quark pair. The data set used in the analysis corresponds to an
integrated luminosity of 680 pb^{-1} collected with the Collider Detector at
Fermilab in Run II. We present 95% confidence level upper limits on the cross
section times branching ratio. Assuming a specific topcolor-assisted
technicolor production model, the leptophobic Z' with width
\Gamma_{Z'}=0.012M_{Z'}, we exclude the mass range M_{Z'} < 725 GeV/c^2 at the
95% confidence level.Comment: 7 pages, 3 figures. submitted to Phys. Rev. Let
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