258 research outputs found
Engineered swift equilibration of a Brownian particle
A fundamental and intrinsic property of any device or natural system is its
relaxation time relax, which is the time it takes to return to equilibrium
after the sudden change of a control parameter [1]. Reducing relax , is
frequently necessary, and is often obtained by a complex feedback process. To
overcome the limitations of such an approach, alternative methods based on
driving have been recently demonstrated [2, 3], for isolated quantum and
classical systems [4--9]. Their extension to open systems in contact with a
thermostat is a stumbling block for applications. Here, we design a
protocol,named Engineered Swift Equilibration (ESE), that shortcuts
time-consuming relaxations, and we apply it to a Brownian particle trapped in
an optical potential whose properties can be controlled in time. We implement
the process experimentally, showing that it allows the system to reach
equilibrium times faster than the natural equilibration rate. We also estimate
the increase of the dissipated energy needed to get such a time reduction. The
method paves the way for applications in micro and nano devices, where the
reduction of operation time represents as substantial a challenge as
miniaturization [10]. The concepts of equilibrium and of transformations from
an equilibrium state to another, are cornerstones of thermodynamics. A textbook
illustration is provided by the expansion of a gas, starting at equilibrium and
expanding to reach a new equilibrium in a larger vessel. This operation can be
performed either very slowly by a piston, without dissipating energy into the
environment, or alternatively quickly, letting the piston freely move to reach
the new volume
International Veterinary Epilepsy Task Force Consensus Proposal: Outcome of therapeutic interventions in canine and feline epilepsy
Common criteria for the diagnosis of drug resistance and the assessment of outcome are needed urgently as a prerequisite for standardized evaluation and reporting of individual therapeutic responses in canine epilepsy. Thus, we provide a proposal for the definition of drug resistance and partial therapeutic success in canine patients with epilepsy. This consensus statement also suggests a list of factors and aspects of outcome, which should be considered in addition to the impact on seizures. Moreover, these expert recommendations discuss criteria which determine the validity and informative value of a therapeutic trial in an individual patient and also suggest the application of individual outcome criteria. Agreement on common guidelines does not only render a basis for future optimization of individual patient management, but is also a presupposition for the design and implementation of clinical studies with highly standardized inclusion and exclusion criteria. Respective standardization will improve the comparability of findings from different studies and renders an improved basis for multicenter studies. Therefore, this proposal provides an in-depth discussion of the implications of outcome criteria for clinical studies. In particular ethical aspects and the different options for study design and application of individual patient-centered outcome criteria are considered
Evaluation of Analytical Methods to Study Aquifer Properties with Pumping Tests in Coastal Aquifers with Numerical Modelling (Motril-Salobreña Aquifer)
Two pumping tests were performed in the unconfined Motril-Salobreña detrital
aquifer in a 250 m-deep well 300 m from the coastline containing both freshwater and
saltwater. It is an artesian well as it is in the discharge zone of this coastal aquifer. The two
observation wells where the drawdowns are measured record the influence of tidal fluctuations, and the well lithological columns reveal high vertical heterogeneity in the aquifer. The
Theis and Cooper-Jacob approaches give average transmissivity (T) and storage
coefficient (S) values of 1460 m2
/d and 0.027, respectively. Other analytical solutions,
modified to be more accurate in the boundary conditions found in coastal aquifers,
provide similar T values to those found with the Theis and Cooper-Jacob methods,
but give very different S values or could not estimate them. Numerical modelling in a
synthetic model was applied to analyse the sensitivity of the Theis and Cooper-Jacob
approaches to the usual boundary conditions in coastal aquifers. The T and S values
calculated from the numerical modelling drawdowns indicate that the regional flow,
variable pumping flows, and tidal effect produce an error of under 10 % compared to results
obtained with classic methods. Fluids of different density (freshwater and saltwater) cause an
error of 20 % in estimating T and of over 100 % in calculating S. The factor most affecting T and
S results in the pumping test interpretation is vertical heterogeneity in sediments, which can
produce errors of over 100 % in both parameters.This research has been financed by Project CGL2012-32892 (Ministerio de EconomĂa y
Competitividad of Spain) and by the Research Group Sedimentary Geology and Groundwater (RNM-369) of the
Junta de AndalucĂa
Cellular Bases of Barbiturate and Phenytoin Anticonvulsant Drug Action
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65509/1/j.1528-1157.1982.tb06093.x.pd
Modeling complex ecological economic systems: toward an evolutionary, dynamic understanding of people and nature
Recent understanding about system dynamics and predictability that has emerged from the study of complex systems is creating new tools for modeling interactions between anthropogenic and natural systems. A range of techniques has become available through advances in computer speed and accessibility and by implementing a broad, interdisciplinary systems view
Family-based association study of the BDNF, COMT and serotonin transporter genes and DSM-IV bipolar-I disorder in children
<p>Abstract</p> <p>Background</p> <p>Over the past decade pediatric bipolar disorder has gained recognition as a potentially more severe and heritable form of the disorder. In this report we test for association with genes coding brain-derived neurotrophic factor (<it>BDNF</it>), the serotonin transporter (<it>SLC6A4</it>), and catechol-O-methyltransferase (<it>COMT</it>).</p> <p>Methods</p> <p>Bipolar-I affected offspring triads (N = 173) were drawn from 522 individuals with 2 parents in 332 nuclear families recruited for genetic studies of pediatric psychopathology at the Clinical and Research Program in Pediatric Psychopharmacology and Adult ADHD at Massachusetts General Hospital.</p> <p>Results</p> <p>We failed to identify an association with the val66 allele in BDNF (OR = 1.23, p = 0.36), the COMT-l allele (OR = 1.27, p = 0.1), or the HTTLPR short allele (OR = 0.87, p = 0.38).</p> <p>Conclusion</p> <p>Our study suggests that the markers examined thus far in <it>COMT </it>and <it>SLC6A4 </it>are not associated with pediatric bipolar disorder and that if the val66met marker in <it>BDNF </it>is associated with pediatric bipolar disorder the magnitude of the association is much smaller than first reported.</p
Assembly of Inflammation-Related Genes for Pathway-Focused Genetic Analysis
Recent identifications of associations between novel variants in inflammation-related genes and several common diseases emphasize the need for systematic evaluations of these genes in disease susceptibility. Considering that many genes are involved in the complex inflammation responses and many genetic variants in these genes have the potential to alter the functions and expression of these genes, we assembled a list of key inflammation-related genes to facilitate the identification of genetic associations of diseases with an inflammation-related etiology. We first reviewed various phases of inflammation responses, including the development of immune cells, sensing of danger, influx of cells to sites of insult, activation and functional responses of immune and non-immune cells, and resolution of the immune response. Assisted by the Ingenuity Pathway Analysis, we then identified 17 functional sub-pathways that are involved in one or multiple phases. This organization would greatly increase the chance of detecting gene-gene interactions by hierarchical clustering of genes with their functional closeness in a pathway. Finally, as an example application, we have developed tagging single nucleotide polymorphism (tSNP) arrays for populations of European and African descent to capture all the common variants of these key inflammation-related genes. Assays of these tSNPs have been designed and assembled into two Affymetrix ParAllele customized chips, one each for European (12,011 SNPs) and African (21,542 SNPs) populations. These tSNPs have greater coverage for these inflammation-related genes compared to the existing genome-wide arrays, particularly in the African population. These tSNP arrays can facilitate systematic evaluation of inflammation pathways in disease susceptibility. For additional applications, other genotyping platforms could also be employed. For existing genome-wide association data, this list of key inflammation-related genes and associated subpathways can facilitate comprehensive inflammation pathway- focused association analyses
Anti-Inflammatory properties of Salograviolide A purified from Lebanese plant Centaurea ainetensis
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