15,833 research outputs found
An algorithm for efficient constrained mate selection
<p>Abstract</p> <p>Background</p> <p>Mate selection can be used as a framework to balance key technical, cost and logistical issues while implementing a breeding program at a tactical level. The resulting mating lists accommodate optimal contributions of parents to future generations, in conjunction with other factors such as progeny inbreeding, connection between herds, use of reproductive technologies, management of the genetic distribution of nominated traits, and management of allele/genotype frequencies for nominated QTL/markers.</p> <p>Methods</p> <p>This paper describes a mate selection algorithm that is widely used and presents an extension that makes it possible to apply constraints on certain matings, as dictated through a group mating permission matrix.</p> <p>Results</p> <p>This full algorithm leads to simpler applications, and to computing speed for the scenario tested, which is several hundred times faster than the previous strategy of penalising solutions that break constraints.</p> <p>Conclusions</p> <p>The much higher speed of the method presented here extends the use of mate selection and enables implementation in relatively large programs across breeding units.</p
Adding control to arbitrary unknown quantum operations
While quantum computers promise significant advantages, the complexity of
quantum algorithms remains a major technological obstacle. We have developed
and demonstrated an architecture-independent technique that simplifies adding
control qubits to arbitrary quantum operations-a requirement in many quantum
algorithms, simulations and metrology. The technique is independent of how the
operation is done, does not require knowledge of what the operation is, and
largely separates the problems of how to implement a quantum operation in the
laboratory and how to add a control. We demonstrate an entanglement-based
version in a photonic system, realizing a range of different two-qubit gates
with high fidelity.Comment: 9 pages, 8 figure
Spinocerebellar ataxia types 1, 2, 3, and 6: disease severity and nonataxia symptoms.
OBJECTIVE: To identify factors that determine disease severity and clinical
phenotype of the most common spinocerebellar ataxias (SCAs), we studied 526
patients with SCA1, SCA2, SCA3. or SCA6.
METHODS: To measure the severity of ataxia we used the Scale for the Assessment
and Rating of Ataxia (SARA). In addition, nonataxia symptoms were assessed with
the Inventory of Non-Ataxia Symptoms (INAS). The INAS count denotes the number of
nonataxia symptoms in each patient.
RESULTS: An analysis of covariance with SARA score as dependent variable and
repeat lengths of the expanded and normal allele, age at onset, and disease
duration as independent variables led to multivariate models that explained 60.4%
of the SARA score variance in SCA1, 45.4% in SCA2, 46.8% in SCA3, and 33.7% in
SCA6. In SCA1, SCA2, and SCA3, SARA was mainly determined by repeat length of the
expanded allele, age at onset, and disease duration. The only factors determining
the SARA score in SCA6 were age at onset and disease duration. The INAS count was
5.0 +/- 2.3 in SCA1, 4.6 +/- 2.2 in SCA2, 5.2 +/- 2.5 in SCA3, and 2.0 +/- 1.7 in
SCA6. In SCA1, SCA2, and SCA3, SARA score and disease duration were the strongest
predictors of the INAS count. In SCA6, only age at onset and disease duration had
an effect on the INAS count.
CONCLUSIONS: Our study suggests that spinocerebellar ataxia (SCA) 1, SCA2, and
SCA3 share a number of common biologic properties, whereas SCA6 is distinct in
that its phenotype is more determined by age than by disease-related factors
Variance in multiplex suspension array assays: A distribution generation machine for multiplex counts
<p>Abstract</p> <p>Background</p> <p>This study attempted to replicate Luminex experimental results for large numbers of beads per classifier using multiplexed assays and routine instrument use conditions.</p> <p>Conclusion</p> <p>Using larger numbers of microspheres per classifier highlights a fundamental stochastic distribution of bead counts issue complicated by other factors. The more classifiers and the higher the count required per classifier there are, the more apparent the distribution of counts per classifier will be, and the more microspheres are required. Additional problems have been identified. Alternate methods of improving precision and reliability are recommended such as intraplexing and multi-well sample replicates to improve precision and confidence.</p
Local Detection of Quantum Correlations with a Single Trapped Ion
As one of the most striking features of quantum mechanics, quantum
correlations are at the heart of quantum information science. Detection of
correlations usually requires access to all the correlated subsystems. However,
in many realistic scenarios this is not feasible since only some of the
subsystems can be controlled and measured. Such cases can be treated as open
quantum systems interacting with an inaccessible environment. Initial
system-environment correlations play a fundamental role for the dynamics of
open quantum systems. Following a recent proposal, we exploit the impact of the
correlations on the open-system dynamics to detect system-environment quantum
correlations without accessing the environment. We use two degrees of freedom
of a trapped ion to model an open system and its environment. The present
method does not require any assumptions about the environment, the interaction
or the initial state and therefore provides a versatile tool for the study of
quantum systems.Comment: 6 Pages, 5 Figures + 6 Pages, 1 Figure of Supplementary Materia
Behavior of a Metabolic Cycling Population at the Single Cell Level as Visualized by Fluorescent Gene Expression Reporters
BACKGROUND: During continuous growth in specific chemostat cultures, budding yeast undergo robust oscillations in oxygen consumption that are accompanied by highly periodic changes in transcript abundance of a majority of genes, in a phenomenon called the Yeast Metabolic Cycle (YMC). This study uses fluorescent reporters of genes specific to different YMC phases in order to visualize this phenomenon and understand the temporal regulation of gene expression at the level of individual cells within the cycling population. METHODOLOGY: Fluorescent gene expression reporters for different phases of the YMC were constructed and stably integrated into the yeast genome. Subsequently, these reporter-expressing yeast were used to visualize YMC dynamics at the individual cell level in cultures grown in a chemostat or in a microfluidics platform under varying glucose concentrations, using fluorescence microscopy and quantitative Western blots. CONCLUSIONS: The behavior of single cells within a metabolic cycling population was visualized using phase-specific fluorescent reporters. The reporters largely recapitulated genome-specified mRNA expression profiles. A significant fraction of the cell population appeared to exhibit basal expression of the reporters, supporting the hypothesis that there are at least two distinct subpopulations of cells within the cycling population. Although approximately half of the cycling population initiated cell division in each permissive window of the YMC, metabolic synchrony of the population was maintained. Using a microfluidics platform we observed that low glucose concentrations appear to be necessary for metabolic cycling. Lastly, we propose that there is a temporal window in the oxidative growth phase of the YMC where the cycling population segregates into at least two subpopulations, one which will enter the cell cycle and one which does not
Effect of Pulsed or Continuous Delivery of Salt on Sensory Perception Over Short Time Intervals
Salt in the human diet is a major risk factor for hypertension and many countries have set targets to reduce
salt consumption. Technological solutions are being sought
to lower the salt content of processed foods without altering their taste. In this study, the approach was to deliver salt solutions in pulses of different concentrations to determine whether a pulsed delivery profile affected sensory perception of salt. Nine different salt profiles were delivered by a Dynataste device and a trained panel assessed their saltiness using time–intensity and single-score sensory techniques. The profile duration (15 s) was designed to match eating conditions and the effects of intensity and duration of the pulses on sensory perception were investigated. Sensory results from the profiles delivered in either water or in a bouillon base were not statistically different. Maximum perceived salt intensities and the area under the time–
intensity curves correlated well with the overall perceived
saltiness intensity despite the stimulus being delivered as
several pulses. The overall saltiness scores for profiles
delivering the same overall amount of sodium were statistically not different from one another suggesting that, in this system, pulsed delivery did not enhance salt
perception but the overall amount of salt delivered in each
profile did affect sensory perception
Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke
Background
Recurrent stroke is a frequent, disabling event after ischemic stroke. This study compared
the efficacy and safety of two antiplatelet regimens — aspirin plus extendedrelease
dipyridamole (ASA–ERDP) versus clopidogrel.
Methods
In this double-blind, 2-by-2 factorial trial, we randomly assigned patients to receive
25 mg of aspirin plus 200 mg of extended-release dipyridamole twice daily or to receive
75 mg of clopidogrel daily. The primary outcome was first recurrence of stroke.
The secondary outcome was a composite of stroke, myocardial infarction, or death
from vascular causes. Sequential statistical testing of noninferiority (margin of 1.075),
followed by superiority testing, was planned.
Results
A total of 20,332 patients were followed for a mean of 2.5 years. Recurrent stroke
occurred in 916 patients (9.0%) receiving ASA–ERDP and in 898 patients (8.8%) receiving
clopidogrel (hazard ratio, 1.01; 95% confidence interval [CI], 0.92 to 1.11). The
secondary outcome occurred in 1333 patients (13.1%) in each group (hazard ratio for
ASA–ERDP, 0.99; 95% CI, 0.92 to 1.07). There were more major hemorrhagic events
among ASA–ERDP recipients (419 [4.1%]) than among clopidogrel recipients (365
[3.6%]) (hazard ratio, 1.15; 95% CI, 1.00 to 1.32), including intracranial hemorrhage
(hazard ratio, 1.42; 95% CI, 1.11 to 1.83). The net risk of recurrent stroke or major
hemorrhagic event was similar in the two groups (1194 ASA–ERDP recipients [11.7%],
vs. 1156 clopidogrel recipients [11.4%]; hazard ratio, 1.03; 95% CI, 0.95 to 1.11).
Conclusions
The trial did not meet the predefined criteria for noninferiority but showed similar rates
of recurrent stroke with ASA–ERDP and with clopidogrel. There is no evidence that either
of the two treatments was superior to the other in the prevention of recurrent
stroke. (ClinicalTrials.gov number, NCT00153062.
What am I not seeing? An Interactive Approach to Social Content Discovery in Microblogs
In this paper, we focus on the informational and user experience benefits of user-driven topic exploration in microblog communities, such as Twitter, in an inspectable, controllable and personalized manner. To this end, we introduce ``HopTopics'' -- a novel interactive tool for exploring content that is popular just beyond a user's typical information horizon in a microblog, as defined by the network of individuals that they are connected to. We present results of a user study (N=122) to evaluate HopTopics with varying complexity against a typical microblog feed in both personalized and non-personalized conditions. Results show that the HopTopics system, leveraging content from both the direct and extended network of a user, succeeds in giving users a better sense of control and transparency. Moreover, participants had a poor mental model for the degree of novel content discovered when presented with non-personalized data in the Inspectable interface
Thermodynamic curvature and black holes
I give a relatively broad survey of thermodynamic curvature , one spanning
results in fluids and solids, spin systems, and black hole thermodynamics.
results from the thermodynamic information metric giving thermodynamic
fluctuations. has a unique status in thermodynamics as being a geometric
invariant, the same for any given thermodynamic state. In fluid and solid
systems, the sign of indicates the character of microscopic interactions,
repulsive or attractive. gives the average size of organized mesoscopic
fluctuating structures. The broad generality of thermodynamic principles might
lead one to believe the same for black hole thermodynamics. This paper explores
this issue with a systematic tabulation of results in a number of cases.Comment: 27 pages, 10 figures, 7 tables, 78 references. Talk presented at the
conference Breaking of Supersymmetry and Ultraviolet Divergences in extended
Supergravity, in Frascati, Italy, March 27, 2013. v2 corrects some small
problem
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