267 research outputs found
Cyclic Multi-Directional Response of Clay Deposits: Evaluating a Constitutive Model
The focus of this study is to verify the capabilities of a constitutive model to mimic a wide range of monotonic and cyclic multi-directional stress paths in clays. The generalized elasto-plastic constitutive formulation of the model enables to describe stress-strain response, accumulation of permanent deformations and excess pore pressure in monotonic and multi-directional cyclic loading. The model is calibrated based on the experimental database on the Gulf of Mexico clay developed at Texas A&M, including the constant rate strain (CRS) consolidation as well as monotonic triaxial tests. Capabilities of the calibrated model to predict the cyclic multi-directional stress paths are then evaluated through comparison with the results of cyclic, circular, and figure 8 multi-directional simple shear tests as a part of the Gulf of Mexico clay experimental database. We also used the extensive database for Boston Blue Clay (BBC) to calibrate model constants and verify its capabilities to mimic the monotonic and cyclic response of lower plasticity clays. The model proves successful to predict a wide range of complicated cyclic multi-directional stress paths for clays
Area of hock hair loss in dairy cows : risk factors and correlation to a categorical scale
Data from 3691 dairy cows from 76 farms were used to investigate the risk factors associated with area of hair loss over the lateral aspect of the hock, and the correlation between the area of hair loss as calculated using a hock map and hock lesion scores determined using a pre-existing categorical scale.
Six factors were associated with a greater area of hair loss, including cows with locomotion score 3, a cleanliness score (10-18/28), high daily milk yield (25.1 - 58.1 kg), poor body condition score (1-1.5), duration of winter housing (≥41 days) and some combinations of cubicle base and bedding materials. Compared with cows housed in cubicles with a concrete base and whole straw or rape straw bedding, cows housed in cubicles with concrete bases with sand or chopped straw bedding had smaller areas of hair loss and cows housed on a mattress base with whole straw or rape straw bedding had a larger area of hair loss.
Area of hair loss, as measured on hock maps, was not significantly different between cows with score 1 (median=23.6 cm2) and score 2 (median=20.3 cm2) on the categorical scale for hock lesions. This suggests that the categorical scale was not reflecting the extent of hair loss and that hock maps are a good alternative for studying the dynamics of hock lesions over time. Further work is required to explore the aetiology of hock lesions and find better ways to control this common condition.
Keywords: Hock lesions; Hair loss; Dairy cow; Welfare; Hock map
Fit for purpose? A cross-sectional study to evaluate the acceptability and usability of HeadUp, a novel neck support collar for neurological neck weakness
The HeadUp collar (previously known as the Sheffield Support Snood) provides support for neck weakness caused by amyotrophic lateral sclerosis (ALS) and has shown to be superior to alternative options in a small cohort of patients from one single center. Here we report the assessment of the HeadUp collar in a larger cohort of patients, exploring the use in other neurological conditions and expanding to other centers across the UK and Ireland. An interventional cross-sectional study design was implemented to investigate the usability and acceptability of the HeadUp collar. A total of 139 patients were recruited for the study, 117 patients had a diagnosis of ALS and 22 patients presented with neck weakness due to other neurological conditions. Participants were assessed at baseline, fitted a HeadUp collar and followed-up one month later. The performance of the HeadUp collar was rated favorably compared to previously worn collars in terms of the ability to eat, drink and swallow. Findings suggest that the collar also permitted a more acceptable range of head movements whilst maintaining a good level of support. We conclude that the HeadUp collar is a suitable option for patients with neck weakness due to ALS and other neurological conditions
Intrinsic and extrinsic properties of quantum systems
The paper attempts to convince that the orthodox interpretation of quantum
mechanics does not contradict philosophical realism by throwing light onto
certain properties of quantum systems that seem to have escaped attention as
yet. The exposition starts with the philosophical notions of realism. Then, the
quantum mechanics as it is usually taught is demoted to a mere part of the
theory called phenomenology of observations, and the common impression about
its contradiction to realism is explained. The main idea of the paper, the
physical notion of intrinsic properties, is introduced and many examples
thereof are given. It replaces the irritating dichotomy of quantum and
classical worlds by a much softer difference between intrinsic and extrinsic
properties, which concern equally microscopic and macroscopic systems. Finally,
the classicality and the quantum measurement are analyzed and found to present
some still unsolved problems. A possible way of dealing with the
Schr\"{o}dinger cat is suggested that is based on the intrinsic properties. A
simple quantum model of one classical property illustrates how our philosophy
may work.Comment: 20 pages, no figure. Comments are wellcom
Changes in supramolecular organization of cyanobacterial thylakoid membrane complexes in response to far-red light photoacclimation
Cyanobacteria are ubiquitous in nature and have developed numerous strategies that allow them to live in a diverse range of environments. Certain cyanobacteria synthesize chlorophylls d and f to acclimate to niches enriched in far-red light (FRL) and incorporate paralogous photosynthetic proteins into their photosynthetic apparatus in a process called FRL-induced photoacclimation (FaRLiP). We characterized the macromolecular changes involved in FRL-driven photosynthesis and used atomic force microscopy to examine the supramolecular organization of photosystem I associated with FaRLiP in three cyanobacterial species. Mass spectrometry showed the changes in the proteome of Chroococcidiopsis thermalis PCC 7203 that accompany FaRLiP. Fluorescence lifetime imaging microscopy and electron microscopy reveal an altered cellular distribution of photosystem complexes and illustrate the cell-to-cell variability of the FaRLiP response
Search for the standard model Higgs boson decaying to a pair in events with no charged leptons and large missing transverse energy using the full CDF data set
We report on a search for the standard model Higgs boson produced in
association with a vector boson in the full data set of proton-antiproton
collisions at TeV recorded by the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45 fb. We
consider events having no identified charged lepton, a transverse energy
imbalance, and two or three jets, of which at least one is consistent with
originating from the decay of a quark. We place 95% credibility level upper
limits on the production cross section times standard model branching fraction
for several mass hypotheses between 90 and . For a Higgs
boson mass of , the observed (expected) limit is 6.7
(3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let
Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data
collected with the CDF II detector at the Tevatron corresponding to an
integrated luminosity of 9.45 fb-1. In events consistent with the decay of the
Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a
neutrino, we set 95% credibility level upper limits on the WH production cross
section times the H->bb branching ratio as a function of Higgs boson mass. At a
Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times
the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by
PRL
Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a Z boson in data collected with the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events
consistent with the decay of the Higgs boson to a bottom-quark pair and the Z
boson to electron or muon pairs, we set 95% credibility level upper limits on
the ZH production cross section times the H -> bb branching ratio as a function
of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a
limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
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