3,520 research outputs found
Potato variety trial
DELAWARE has been the only variety of Potato grown commercially in Western Australia. This is due to the fact that in the past an early maturing variety with a short dormancy period has been required to suit both hill plantings and swamp crops.
However, with the advent of sprinkler irrigation and hence better control of moisture and growing conditions, the need for early maturing varieties has ceased to exist in some districts.
There has been consequently an increasing interest in testing varieties which have proved high yielding and of good quality in other parts of the world
Uncovering regulatory pathways that affect hematopoietic stem cell function using 'genetical genomics'
We combined large-scale mRNA expression analysis and gene mapping to identify genes and loci that control hematopoietic stem cell (HSC) function. We measured mRNA expression levels in purified HSCs isolated from a panel of densely genotyped recombinant inbred mouse strains. We mapped quantitative trait loci (QTLs) associated with variation in expression of thousands of transcripts. By comparing the physical transcript position with the location of the controlling QTL, we identified polymorphic cis-acting stem cell genes. We also identified multiple trans-acting control loci that modify expression of large numbers of genes. These groups of coregulated transcripts identify pathways that specify variation in stem cells. We illustrate this concept with the identification of candidate genes involved with HSC turnover. We compared expression QTLs in HSCs and brain from the same mice and identified both shared and tissue-specific QTLs. Our data are accessible through WebQTL, a web-based interface that allows custom genetic linkage analysis and identification of coregulated transcripts.
The expected payoff to Internet auctions
In an Internet auction, the expected payoff acts as a benchmark of the reasonableness of the price that is paid for the purchased item. Since the number of potential bidders is not observable, the expected payoff is difficult to estimate accurately. We approach this problem by considering the bids as a record and 2-record sequence of the potential bidde
Cross-classified multilevel models improved standard error estimates of covariates in clinical outcomes – a simulation study
Objective: To compare estimates of effect and variability resulting from standard linear regression analysis and hierarchical multilevel analysis with cross-classified multilevel analysis under various scenarios. Study design and setting: We performed a simulation study based on a data structure from an observational study in clinical mental health care. We used a Markov chain Monte Carlo approach to simulate 18 scenarios, varying sample sizes, cluster sizes, effect sizes and between group variances. For each scenario, we performed standard linear regression, multilevel regression with random intercept on patient level, multilevel regression with random intercept on nursing team level and cross-classified multilevel analysis. Results: Applying cross-classified multilevel analyses had negligible influence on the effect estimates. However, ignoring cross-classification led to underestimation of the standard errors of the covariates at the two cross-classified levels and to invalidly narrow confidence intervals. This may lead to incorrect statistical inference. Varying sample size, cluster size, effect size and variance had no meaningful influence on these findings. Conclusion: In case of cross-classified data structures, the use of a cross-classified multilevel model helps estimating valid precision of effects, and thereby, support correct inferences
Extreme value distributions and Renormalization Group
In the classical theorems of extreme value theory the limits of suitably
rescaled maxima of sequences of independent, identically distributed random
variables are studied. So far, only affine rescalings have been considered. We
show, however, that more general rescalings are natural and lead to new limit
distributions, apart from the Gumbel, Weibull, and Fr\'echet families. The
problem is approached using the language of Renormalization Group
transformations in the space of probability densities. The limit distributions
are fixed points of the transformation and the study of the differential around
them allows a local analysis of the domains of attraction and the computation
of finite-size corrections.Comment: 16 pages, 5 figures. Final versio
Association between characteristics of nursing teams and patients' aggressive behavior in closed psychiatric wards
PURPOSE: Estimate the effect of nursing, shift, and patient characteristics on patients' aggression. DESIGN AND METHODS: Follow‐up study on a closed psychiatric ward was performed to estimate the effect of nursing team characteristics and patient characteristics on the incidence of aggression. FINDINGS: The incidence of aggression (n = 802 in sample) was lower in teams with >75% male nurses. Teams scoring high on extraversion experienced more verbal aggression and teams scoring high on neuroticism experienced more physical aggression. Younger patients and/or involuntarily admitted patients were more frequently aggressive. PRACTICE IMPLICATIONS: These findings could stimulate support for nurses to prevent aggression
Extreme fluctuations in noisy task-completion landscapes on scale-free networks
We study the statistics and scaling of extreme fluctuations in noisy
task-completion landscapes, such as those emerging in synchronized
distributed-computing networks, or generic causally-constrained queuing
networks, with scale-free topology. In these networks the average size of the
fluctuations becomes finite (synchronized state) and the extreme fluctuations
typically diverge only logarithmically in the large system-size limit ensuring
synchronization in a practical sense. Provided that local fluctuations in the
network are short-tailed, the statistics of the extremes are governed by the
Gumbel distribution. We present large-scale simulation results using the exact
algorithmic rules, supported by mean-field arguments based on a coarse-grained
description.Comment: 16 pages, 6 figures, revte
Lacosamide monotherapy in clinical practice: A retrospective chart review
Objective: To assess effectiveness and tolerability of first-line and conversion to lacosamide monotherapy for focal seizures. Materials and Methods: Retrospective, non-interventional chart review of lacosamide monotherapy patients aged ≥16 years in Europe. Outcomes included retention rate at observational point (OP) 3 (12 ± 3 months), seizure freedom rates at OP2 (6 ± 3 months) and OP3 and adverse drug reactions (ADRs). Results: A total of 439 patients were included (98 first-line and 341 conversion to monotherapy; 128 aged ≥65 years [25 first-line and 103 conversion to monotherapy]). First-line and conversion to monotherapy retention rates were 60.2% (59/98; 95% confidence interval [CI] 49.8%-70.0%) and 62.5% (213/341; 57.1%-67.6%), respectively. Kaplan-Meier estimates of 12-month retention rates were 81.2% and 91.4% for first-line and conversion to monotherapy, respectively. First-line and conversion to monotherapy retention rates in patients aged ≥65 years were 60.0% (38.7%-78.9%) and 68.9% (59.1%-77.7%), respectively. At OP2, 66.3% of first-line and 63.0% of conversion to monotherapy patients were seizure free. At OP3, 60.2% of first-line and 52.5% of conversion to monotherapy patients were seizure free. In the ≥65 years subgroup, seizure freedom rates at OP2 were 72.0% and 68.0% for first-line and converted to monotherapy, respectively, and at OP3, 68.0% and 56.3%, respectively. Overall, 52 of 439 (11.8%) patients reported ADRs (16.4% in ≥65 years subgroup), most commonly dizziness (5.0%), headache (2.1%) and somnolence (1.6%). Conclusions: Lacosamide was effective and well tolerated as first-line or conversion to monotherapy in a clinical setting in adult and elderly patients with focal seizuresThis study was supported by UCB Pharm
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