10,229 research outputs found
Active adjustment of the cervical spine during pitch production compensates for shape: The ArtiVarK study
The anterior lordosis of the cervical spine is thought to contribute to pitch (fo) production by influencing cricoid rotation as a function of larynx height. This study examines the matter of inter-individual variation in cervical spine shape and whether this has an influence on how fo is produced along increasing or decreasing scales, using the ArtiVarK dataset, which contains real-time MRI pitch production data. We find that the cervical spine actively participates in fo production, but the amount of displacement depends on individual shape. In general, anterior spine motion (tending toward cervical lordosis) occurs for low fo, while posterior movement (tending towards cervical kyphosis) occurs for high fo
ELEMENTS OF CATTLE FEEDING PROFITABILITY IN MIDWEST FEEDLOTS
Conventional wisdom and earlier research have concluded that cattle feeding profitability is more determined by feeder and fed cattle prices than by animal performance. This study examined cross-sectional and time-series data from over 1600 pens of cattle in more than 220 feedlots in the upper Midwest where weather and lot conditions are thought to influence feedlot profitability. In addition to input and output prices and animal performance, other factors found to significantly impact cattle feeding profitability were sex, placement weight, facility design, and to a lesser extent placement season.cattle feedlots, probability, risk, Livestock Production/Industries,
Structure of Magnetocentrifugal Disk-Winds: From the Launching Surface to Large Distances
Protostellar jets and winds are probably driven magnetocentrifugally from the
surface of accretion disks close to the central stellar objects. The exact
launching conditions on the disk, such as the distributions of magnetic flux
and mass ejection rate, are poorly unknown. They could be constrained from
observations at large distances, provided that a robust model is available to
link the observable properties of the jets and winds at the large distances to
the conditions at the base of the flow. We discuss the difficulties in
constructing such large-scale wind models, and describe a novel technique which
enables us to numerically follow the acceleration and propagation of the wind
from the disk surface to arbitrarily large distances and the collimation of
part of the wind into a dense, narrow ``jet'' around the rotation axis. Special
attention is paid to the shape of the jet and its mass flux relative to that of
the whole wind. The mass flux ratio is a measure of the jet formation
efficiency.Comment: 6 pages, figures included. To appear in "The Origins of Stars and
Planets: The VLT View". J. Alves and M. McCaughrean, editor
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Mutational signatures in colon cancer.
ObjectiveRecently, many tumor sequencing studies have inferred and reported on mutational signatures, short nucleotide patterns at which particular somatic base substitutions appear more often. A number of signatures reflect biological processes in the patient and factors associated with cancer risk. Our goal is to infer mutational signatures appearing in colon cancer, a cancer for which environmental risk factors vary by cancer subtype, and compare the signatures to those in adult stem cells from normal colon. We also compare the mutational signatures to others in the literature.ResultsWe apply a probabilistic mutation signature model to somatic mutations previously reported for six adult normal colon stem cells and 431 colon adenocarcinomas. We infer six mutational signatures in colon cancer, four being specific to tumors with hypermutation. Just two signatures explained the majority of mutations in the small number of normal aging colon samples. All six signatures are independently identified in a series of 295 Chinese colorectal cancers
Local interaction scale controls the existence of a non-trivial optimal critical mass in opinion spreading
We study a model of opinion formation where the collective decision of group
is said to happen if the fraction of agents having the most common opinion
exceeds a threshold value, a \textit{critical mass}. We find that there exists
a unique, non-trivial critical mass giving the most efficient convergence to
consensus. In addition, we observe that for small critical masses, the
characteristic time scale for the relaxation to consensus splits into two. The
shorter time scale corresponds to a direct relaxation and the longer can be
explained by the existence of intermediate, metastable states similar to those
found in [P.\ Chen and S.\ Redner, Phys.\ Rev.\ E \textbf{71}, 036101 (2005)].
This longer time-scale is dependent on the precise condition for
consensus---with a modification of the condition it can go away.Comment: 4 pages, 6 figure
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