1,666 research outputs found
Speeding up Thermalisation via Open Quantum System Variational Optimisation
Optimizing open quantum system evolution is an important step on the way to
achieving quantum computing and quantum thermodynamic tasks. In this article,
we approach optimisation via variational principles and derive an open quantum
system variational algorithm explicitly for Lindblad evolution in Liouville
space. As an example of such control over open system evolution, we control the
thermalisation of a qubit attached to a thermal Lindbladian bath with a damping
rate . Since thermalisation is an asymptotic process and the
variational algorithm we consider is for fixed time, we present a way to
discuss the potential speedup of thermalisation that can be expected from such
variational algorithms.Comment: 10 pages, 4 figures, comments welcom
DEVELOPING A PERFORMANCE IMPORTANCE MATRIX FOR A PUBLIC SECTOR BUS TRANSPORT COMPANY: A CASE STUDY
This paper presents a study of comparison of the importance attached by the service providers’ and the customers’ with respect to eighteen service characteristics towards the public transportation services provided by a bus company. The survey was conducted in three bus depots in one division of a state road transport undertaking (SRTU) in south India. The importance the SRTU and the customers attach to these characteristics indicates significant differences. This reveals the existence of a gap between customers’ expectations and the service provided by the company. Finally the customer retention and customer development criteria have been. identified.Performance importance matrix, Customer expectations, Public bus transport, Radar chart.
The Role of Sensory Experiences and Information on the Willingness to Pay for Organic Wheat Bread
This study examined the size and the determinants of the price premium a sample of Edmonton-area consumers was willing to pay for organic wheat bread. The development of these premiums included consideration of providing information on health or environmental advantages of organic production and consideration of sensory (taste) acceptance. To do this conventional and organic wheat was grown under similar conditions and milled and baked into 60% whole wheat bread under identical conditions. Samples of these breads were presented to consumers for sensory acceptance and a survey of their attitudes, behaviours and characteristics. The survey included a closed-ended contingent valuation question to examine consumers' willingness-to-pay (WTP) premiums for the organic bread. A trained sensory panel was used to quantify differences in the sensory characteristics of the two breads. The results suggest that in the absence of taste information respondents' WTP when environmental information was provided was greater than WTP when health information was given. When sensory taste information was included, however, the WTP estimates under the health information treatment were about twice those under the environmental information. The trained sensory panel observed the two treatments of bread to differ in texture but not in flavor, aroma or colour characteristics. The implications of these findings are that successful marketing of organic foods depends on circumstance - in the absence of sensory experience the environmental benefits of organic production appear to be more appealing than potential health benefits. Health claims are only viewed positively when the product can be tasted. Sensory scientists should use caution in interpreting WTP estimates in that they must take into account the type of information and placement of WTP questions in their study designs. We also found that sensory variables when included in the regression model had statistically significant effects on WTP estimates. The economic significance of including these variables in the logit model was limited, however. Nevertheless we feel that under some circumstances economists may find it advantageous to include sensory information in their models of food demand.Organic foods, price premium, willingness to pay, taste, health, environment, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Q13, Q18,
Ecosystem Approach to Fisheries Management (Essential EAFM) training and TOT in Sri Lanka
This report presents presentations from representatives of 12 countries, key outcomes and recommendations for the future
Epigenetic suppression of hippocampal calbindin-D28k by ΔFosB drives seizure-related cognitive deficits.
The calcium-binding protein calbindin-D28k is critical for hippocampal function and cognition, but its expression is markedly decreased in various neurological disorders associated with epileptiform activity and seizures. In Alzheimer\u27s disease (AD) and epilepsy, both of which are accompanied by recurrent seizures, the severity of cognitive deficits reflects the degree of calbindin reduction in the hippocampal dentate gyrus (DG). However, despite the importance of calbindin in both neuronal physiology and pathology, the regulatory mechanisms that control its expression in the hippocampus are poorly understood. Here we report an epigenetic mechanism through which seizures chronically suppress hippocampal calbindin expression and impair cognition. We demonstrate that ΔFosB, a highly stable transcription factor, is induced in the hippocampus in mouse models of AD and seizures, in which it binds and triggers histone deacetylation at the promoter of the calbindin gene (Calb1) and downregulates Calb1 transcription. Notably, increasing DG calbindin levels, either by direct virus-mediated expression or inhibition of ΔFosB signaling, improves spatial memory in a mouse model of AD. Moreover, levels of ΔFosB and calbindin expression are inversely related in the DG of individuals with temporal lobe epilepsy (TLE) or AD and correlate with performance on the Mini-Mental State Examination (MMSE). We propose that chronic suppression of calbindin by ΔFosB is one mechanism through which intermittent seizures drive persistent cognitive deficits in conditions accompanied by recurrent seizures
Spatiotemporal Compound Wavelet Matrix Framework for Multiscale/Multiphysics Reactor Simulation: Case Study of a Heterogeneous Reaction/Diffusion System
We present a mathematical method for efficiently compounding information from different models of species diffusion from a chemically reactive boundary. The proposed method is intended to serve as a key component of a multiscale/ multiphysics framework for heterogeneous chemically reacting processes. An essential feature of the method is the merging of wavelet representations of the different models and their corresponding time and length scales. Up-and-downscaling of the information between the scales is accomplished by application of a compounding wavelet operator, which is assembled by establishing limited overlap in scales between the models. We show that the computational efficiency gain and potential error associated with the method depend on the extent of scale overlap and wavelet filtering used. We demonstrate the method for an example problem involving a two-dimensional chemically reactive boundary and first order reactions involving two species
Two Stage Leather Dyeing - A Novel Approach to Minimize the Dye Discharge in the Effluent
Large quantities of synthetic dyes are used in tanneries for coloring leathers. A significant portion of the dyes offered do not fix to the leather and the un-utilized dye is discharged in the effluent, which may be environmentally harmful as it may require a long time for degradation. Depending upon the wastewater treatment methods adopted, sometimes these dyes may generate several highly toxic compounds. These dyes, when discharged into water bodies or land, may also cause severe environmental and health problems. Up to 10% (weight/weight of leather) dye is used in the dyeing process of conventional leather making. There are several physiochemical methods reported for treatment of dyes in effluent, which mainly degrade and remove the dye in effluent and do not aim for recovery and reuse of dye. In the present study an attempt has been made to modify the dyeing process in such a way that minimum dye is discharged in the effluent. Most of the un-utilized dye is recovered and recycled or re-utilized in subsequent dyeing. The visual and instrumental examination of the dyed leathers with this modified dyeing method led to encouraging results. This approach has not only reduced the dye discharge after dyeing but also facilitated substantial reduction in dye input by reuse thereby providing economic benefit to the tanners. The study was carried out for a specific synthetic acid dye and should also be easily extended to other class of dyes.ResumenGrandes cantidades de colorantes sintéticos se utilizan en las curtiembres para colorear cueros. Una parte significativa de los colorantes que se ofrecen no se fijan al cuero y el colorante no utilizado se descarga en el efluente, lo que puede ser dañino para el ambiente, ya que puede requerir mucho tiempo para su degradación. Dependiendo de los métodos de tratamiento de aguas residuales adoptados, a veces estos colorantes puede generar varios compuestos altamente tóxicos. Estos colorantes, cuando se descargan en los cuerpos de agua o tierra, también puede causar graves problemas ambientales y de salud. Hasta un 10% (peso / peso de cuero) del colorante se utiliza en el proceso de teñido en la fabricación convencional del cuero. Hay varios métodos físico-químicos reportados para el tratamiento de los colorantes en los efluentes, que degradan y eliminan principalmente el colorante en los efluentes y no tienen como objetivo la recuperación y reutilización de colorante. En el presente estudio un intento se ha hecho para modificar el proceso de tintura de tal manera que una mínima cantidad del colorante se descarga en el efluente. La mayoría de los colorantes no utilizados se recupera y se recicla o reutiliza en posteriores tinturas. El examen visual e instrumental de los cueros teñidos con este método de tintura modificada ha dado resultados alentadores. Este enfoque no sólo ha reducido la descarga de colorante después del teñido, sino también facilitó la reducción sustancial de la oferta de colorantes por la reutilización de tal modo que proporciona beneficios económicos a los curtidores. El estudio se llevó a cabo para un colorante ácido sintético específico y debería también extenderse fácilmente a otra clase de colorantes
The number of transmission channels through a single-molecule junction
We calculate transmission eigenvalue distributions for Pt-benzene-Pt and
Pt-butadiene-Pt junctions using realistic state-of-the-art many-body
techniques. An effective field theory of interacting -electrons is used to
include screening and van der Waals interactions with the metal electrodes. We
find that the number of dominant transmission channels in a molecular junction
is equal to the degeneracy of the molecular orbital closest to the metal Fermi
level.Comment: 9 pages, 8 figure
Global skin colour prediction from DNA
Human skin colour is highly heritable and externally visible with relevance in medical, forensic, and anthropological genetics. Although eye and hair colour can already be predicted with high accuracies from small sets of carefully selected DNA markers, knowledge about the genetic predictability of skin colour is limited. Here, we investigate the skin colour predictive value of 77 single-nucleotide polymorphisms (SNPs) from 37 genetic loci previously associated with human pigmentation using 2025 individuals from 31 global populations. We identified a minimal set of 36 highly informative skin colour predictive SNPs and developed a statistical prediction model capable of skin colour prediction on a global scale. Average cross-validated prediction accuracies expressed as area under the receiver-operating characteristic curve (AUC) ± standard deviation were 0.97 ± 0.02 for Light, 0.83 ± 0.11 for Dark, and 0.96 ± 0.03 for Dark-Black. When using a 5-category, this resulted in 0.74 ± 0.05 for Very Pale, 0.72 ± 0.03 for Pale, 0.73 ± 0.03 for Intermediate, 0.87±0.1 for Dark, and 0.97 ± 0.03 for Dark-Black. A comparative analysis in 194 independent samples from 17 populations demonstrated that our model outperformed a previously proposed 10-SNP-classifier approach with AUCs rising from 0.79 to 0.82 for White, comparable at the intermediate level of 0.63 and 0.62, respectively, and a large increase from 0.64 to 0.92 for Black. Overall, this study demonstrates that the chosen DNA markers and prediction model, particularly the 5-category level; allow skin colour predictions within and between continental regions for the first time, which will serve as a valuable resource for future applications in forensic and anthropologic genetics
Green function techniques in the treatment of quantum transport at the molecular scale
The theoretical investigation of charge (and spin) transport at nanometer
length scales requires the use of advanced and powerful techniques able to deal
with the dynamical properties of the relevant physical systems, to explicitly
include out-of-equilibrium situations typical for electrical/heat transport as
well as to take into account interaction effects in a systematic way.
Equilibrium Green function techniques and their extension to non-equilibrium
situations via the Keldysh formalism build one of the pillars of current
state-of-the-art approaches to quantum transport which have been implemented in
both model Hamiltonian formulations and first-principle methodologies. We offer
a tutorial overview of the applications of Green functions to deal with some
fundamental aspects of charge transport at the nanoscale, mainly focusing on
applications to model Hamiltonian formulations.Comment: Tutorial review, LaTeX, 129 pages, 41 figures, 300 references,
submitted to Springer series "Lecture Notes in Physics
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