1,254 research outputs found
Entanglement trapping in a non-stationary structured reservoir
We study a single two-level atom interacting with a reservoir of modes
defined by a reservoir structure function with a frequency gap. Using the
pseudomodes technique, we derive the main features of a trapping state formed
in the weak coupling regime. Utilising different entanglement measures we show
that strong correlations and entanglement between the atom and the modes are in
existence when this state is formed. Furthermore, an unexpected feature for the
reservoir is revealed. In the long time limit and for weak coupling the
reservoir spectrum is not constant in time.Comment: 10 pages, 16 figure
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Ecosystem-scale Selenium Model for the San Francisco Bay-Delta Regional Ecosystem Restoration Implementation Plan
Environmental restoration, regulatory protections, and competing interests for water are changing the balance of selenium (Se) discharges to the San Francisco Bay–Delta Estuary (Bay–Delta). The model for Se described here as part of the Delta Regional Ecosystem Restoration Implementation Plan (DRERIP) draws both from the current state of knowledge of the Bay–Delta and of environmental Se science. It is an ecosystem-scale methodology that is a conceptual and quantitative tool to (1) evaluate implications of Se contamination; (2) better understand protection for fish and aquatic-dependent wildlife; and (3) help evaluate future restoration actions. The model builds from five basic principles that determine ecological risks from Se in aquatic environments: (1) dissolved Se transformation to particulate material Se, which is partly driven by the chemical species of dissolved Se, sets dynamics at the base of the food web; (2) diet drives bioavailability of Se to animals; (3) bioaccumulation differs widely among invertebrates, but not necessarily among fish; (4) ecological risks differ among food webs and predator species; and (5) risk for each predator is driven by a combination of exposures via their specific food web and the species’ inherent sensitivity to Se toxicity. Spatially and temporally matched data sets across media (i.e., water, suspended particulate material, prey, and predator) are needed for initiating modeling and for providing ecologically consistent predictions. The methodology, applied site-specifically to the Bay–Delta, includes use of (1) salinity-specific partitioning factors based on empirical estuary data to quantify the effects of dissolved speciation and phase transformation; (2) species-specific dietary biodynamics to quantify foodweb bioaccumulation; and (3) habitat use and life-cycle data for Bay–Delta predator species to illustrate exposure. Model outcomes show that the north Bay–Delta functions as an efficient biomagnifier of Se in benthic food webs, with the greatest risks to predaceous benthivores occurring under low flow conditions. Improving the characterization of ecological risks from Se in the Bay–Delta will require modernization of the Se database and continuing integration of biogeochemical, ecological, and hydrological dynamics into the model
DBT, FAP, and ACT: How empirically oriented are the new behavior therapy technologies?
Empirically validated methods for reducing stigma and prejudice toward recipients of behavioral healthcare services are badly needed. In the present study, two packages presented in one day workshops were compared to a biologically oriented Educational Control condition in the alleviation of stigmatizing attitudes in drug abuse counselors. One, Acceptance and Commitment Training (ACT), utilized acceptance, defusion, mindfulness, and values methods. The other, Multicultural Training, sensitized participants to group prejudices and biases. Measures of stigma and burnout were taken pre-training, post-training, and after a three month follow-up. Results showed that Multicultural Training had an impact on stigmatizing attitudes and burnout post-intervention but not at follow-up, but showed better gains in a sense of personal accomplishment as compared to the Educational Control at follow-up. ACT had a positive impact on stigma at follow-up and on burnout at post-treatment and follow-up and follow-up gains in burnout exceeded those of Multicultural Training. ACT also significantly changed the believability of stigmatizing attitudes. This process mediated the impact of ACT but not Multicultural Training on follow-up stigma and burnout. This preliminary study opens new avenues for reducing stigma and burnout in behavioral health counselors
Linear optical properties of organic microcavity polaritons with non-Markovian Quantum State Diffusion
Hybridisation of the cavity modes and the excitons to polariton states
together with the coupling to the vibrational modes determine the linear
optical properties of organic semiconductors in microcavities. In this article
we compute the refractive index for such system using the
Holstein-Tavis-Cummings model and determine then the linear optical properties
using the transfer matrix method. We first extract the parameters for the
exciton in our model from fitting to experimentally measured absorption of a
2,7-bis [9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl) fluorene
(TDAF) molecular thin film. Then we compute the reflectivity of such a thin
film in a metal clad microcavity system by including the dispersive microcavity
mode to the model. We compute susceptibility of the model systems evolving just
a single state vector by using the non-Markovian Quantum State Diffusion. The
computed location and height of the lower and upper polaritons agree with the
experiment within the estimated errorbars for small angles ().
For larger angles the location of the polariton resonances are within the
estimated error.Comment: 10 pages, 4 figure
Local in time master equations with memory effects: Applicability and interpretation
Non-Markovian local in time master equations give a relatively simple way to
describe the dynamics of open quantum systems with memory effects. Despite
their simple form, there are still many misunderstandings related to the
physical applicability and interpretation of these equations. Here we clarify
these issues both in the case of quantum and classical master equations. We
further introduce the concept of a classical non-Markov chain signified through
negative jump rates in the chain configuration.Comment: Special issue on loss of coherence and memory effects in quantum
dynamics, J. Phys. B., to appea
The Need for Head Protection Protocols for Craniectomy Patients during Rest, Transfers and Turning
After craniectomy, patients are generally advised to wear a helmet when mobilising to protect the unshielded brain from damage. However, there exists limited guidance regarding head protection for patients at rest and when being transferred or turned. Here, we emphasise the need for such protocols and utilise evidence from several sources to affirm our viewpoint. A literature search was first performed using MEDLINE and EMBASE, looking for published material relating to head protection for patients post-craniectomy during rest, transfer or turning. No articles were identified using a wide-ranging search strategy. Next, we surveyed and interviewed staff and patients from our neurosurgical centre to ascertain how often their craniectomy site was exposed to external pressure and the precautions taken to prevent this. 59% of patients admitted resting in contact with the craniectomy site, in agreement with the observations of 67% of staff. In 63% of these patients, this occurred on a daily basis and for some, was associated with symptoms suggestive of raised intracranial pressure. 44% of staff did not use a method to prevent craniectomy site contact while 65% utilised no additional precautions during transfer or turning. 63% of patients received no information about avoiding craniectomy site contact upon discharge, and almost all surveyed wished for resting head protection if it were available. We argue that pragmatic guidelines are needed and that our results support this perspective. As such, we offer a simple, practical protocol which can be adopted and iteratively improved as further evidence becomes available in this area
Identifying the origin of delayed electroluminescence in a polariton organic light-emitting diode
Modifying the energy landscape of existing molecular emitters is an
attractive challenge with favourable outcomes in chemistry and organic
optoelectronic research. It has recently been explored through strong
light-matter coupling studies where the organic emitters were placed in an
optical cavity. Nonetheless, a debate revolves around whether the observed
change in the material properties represents novel coupled system dynamics or
the unmasking of pre-existing material properties induced by light-matter
interactions. Here, for the first time, we examined the effect of strong
coupling in polariton organic light-emitting diodes via time-resolved
electroluminescence studies. We accompanied our experimental analysis with
theoretical fits using a model of coupled rate equations accounting for all
major mechanisms that can result in delayed electroluminescence in organic
emitters. We found that in our devices the delayed electroluminescence was
dominated by emission from trapped charges and this mechanism remained
unmodified in the presence of strong coupling.Comment: 11 pages + 8 supp pages, 4 figures + 8 supp figure
The failure of suicide prevention in primary care: family and GP perspectives - a qualitative study
Background Although Primary care is crucial for suicide prevention, clinicians tend to report completed suicides in their care as non-preventable. We aimed to examine systemic inadequacies in suicide prevention from the perspectives of bereaved family members and GPs.Methods Qualitative study of 72 relatives or close friends bereaved by suicide and 19 General Practitioners who have experienced the suicide of patients.Results Relatives highlight failures in detecting symptoms and behavioral changes and the inability of GPs to understand the needs of patients and their social contexts. A perceived overreliance on anti-depressant treatment is a major source of criticism by family members. GPs tend to lack confidence in the recognition and management of suicidal patients, and report structural inadequacies in service provision.Conclusions Mental health and primary care services must find innovative and ethical ways to involve families in the decision-making process for patients at risk of suicide
QTL/microarray approach using pathway information
<p>Abstract</p> <p>Background</p> <p>A combined quantitative trait loci (QTL) and microarray-based approach is commonly used to find differentially expressed genes which are then identified based on the known function of a gene in the biological process governing the trait of interest. However, a low cutoff value in individual gene analyses may result in many genes with moderate but meaningful changes in expression being missed.</p> <p>Results</p> <p>We modified a gene set analysis to identify intersection sets with significantly affected expression for which the changes in the individual gene sets are less significant. The gene expression profiles in liver tissues of four strains of mice from publicly available microarray sources were analyzed to detect trait-associated pathways using information on the QTL regions of blood concentrations of high density lipoproteins (HDL) cholesterol and insulin-like growth factor 1 (IGF-1). Several metabolic pathways related to HDL levels, including lipid metabolism, ABC transporters and cytochrome P450 pathways were detected for HDL QTL regions. Most of the pathways identified for the IGF-1 phenotype were signal transduction pathways associated with biological processes for IGF-1's regulation.</p> <p>Conclusion</p> <p>We have developed a method of identifying pathways associated with a quantitative trait using information on QTL. Our approach provides insights into genotype-phenotype relations at the level of biological pathways which may help to elucidate the genetic architecture underlying variation in phenotypic traits.</p
Caries inhibitory effect of fluoridated sugar in a trial in Indonesia
The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: In some regional areas of Indonesia, caries prevalence is increasing rapidly. As water, salt or milk fluoridation were not considered suitable for use throughout Indonesia, and fluoridated tooth paste is mostly too expensive, a fluoride cocrystallised sugar containing 10ppm fluoride was prepared. Its efficacy in inhibiting caries development was tested in a field trial. Methods: The field trial was established in Medan, Sumatera. All dietary background data necessary to ensure the safety of a trial were collected. Subjects chosen were 176 children who were residents of two orphanages and a boarding school for children of poor rural families. The trial used a double-blind format. Close monitoring of fluoride consumption was maintained, and fluoride excretion rates were assessed six monthly by urinary fluoride analysis. Results: Records of total tooth surface caries present initially and after 18 months of sugar supply showed that the children using fluoridated sugar had significantly fewer carious lesions than those who used normal sugar. Conclusion: This result indicates that sugar might be considered as a further vehicle for supplementary dietary fluoride in communities where there is a high caries prevalence or high caries risk and little exposure to fluoride.Mulyani, J McIntyr
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