814 research outputs found
Systematics of g factors of 2_1^+ states in even-even nuclei from Gd to Pt: A microscopic description by the projected shell model
The systematics of g factor of first excited 2^+ state vs neutron number N is
studied by the projected shell model. The study covers the even-even nuclei of
all isotopic chains from Gd to Pt. g factors are calculated by using the
many-body wavefunctions that reproduces well the energy levels and B(E2)'s of
the ground-state bands. For Gd to W isotopes the characteristic feature of the
g factor data along an isotopic chain is described by the present model.
Deficiency of the model in the g factor description for the heavier Os and Pt
isotopes is discussed.Comment: 9 pages, 5 figure
What does it mean when we ask the public if they are “confident” in policing? The Trust, Fairness, Presence model of “public confidence”
‘Confidence’ is widely taken to be a crucial measure of the relationship between citizens and public services such as policing. It is acknowledged that confidence is multifaceted and hard to measure, but often discussions are based on one ‘headline’ rating of a single item, for instance: ‘What is your level of confidence in…’. The subsequent focus for research is explaining what might drive ‘confidence’, or what it might predict. We are interested in a more fundamental question: what does it mean when we ask the public if they are ‘confident’ in policing? To answer this, we analyse extensive and detailed survey data specifically designed to measure public confidence, within the jurisdiction of a UK police force – West Midlands Police. We develop then validate a three-part model of confidence as trust, fairness and presence, and find good evidence to support this model across different waves of the survey. This extends existing literature with implications for policy
Structure of laponite-styrene precursor dispersions for production of advanced polymer-clay nanocomposites
One method for production of polymer-clay nanocomposites involves dispersal of surface-modified clay in a polymerisable monomeric solvent, followed by fast in situ polymerisation. In order to tailor the properties of the final material we aim to control the dispersion state of the clay in the precursor solvent. Here, we study dispersions of surface-modified Laponite, a synthetic clay, in styrene via large-scale Monte-Carlo simulations and experimentally, using small angle X-ray and static light scattering. By tuning the effective interaction between simulated laponite particles we are able to reproduce the experimental scattering intensity patterns for this system, with good accuracy over a wide range of length scales. However, this agreement could only be obtained by introducing a permanent electrostatic dipole moment into the plane of each Laponite particle, which we explain in terms of the distribution of substituted metal atoms within each Laponite particle. This suggests that Laponite dispersions, and perhaps other clay suspensions, should display some of the structural characteristics of dipolar fluids. Our simulated structures show aggregation regimes ranging from networks of long chains to dense clusters of Laponite particles, and we also obtain some intriguing ‘globular’ clusters, similar to capsids. We see no indication of any ‘house-of-cards’ structures. The simulation that most closely matches experimental results indicates that gel-like networks are obtained in Laponite dispersions, which however appear optically clear and non-sedimenting over extended periods of time. This suggests it could be difficult to obtain truly isotropic equilibrium dispersion as a starting point for synthesis of advanced polymer-clay nanocomposites with controlled structures
The Effects of Serotonin Receptor Antagonists on Contraction and Relaxation Responses Induced by Electrical Stimulation in the Rat Small Intestine
Background: The main source of 5-HT in body is in enterchromafin cells of intestine, different studies mentioned different roles for endogenous 5-HT and receptors involved and it is not clearified the mechanism of action of endogenous 5-HT.
Objectives: To study the role of endogenous 5-HT on modulation of contraction and relaxation responses induced by electrical field stimulation (EFS) in different regions of the rat intestine.
Materials and Methods: Segments taken from the rat duodenum, jejunum, mid and terminal ileum were vertically mounted, connected to a transducer and exposed to EFS with different frequencies in the absence and presence of various inhibitors of enteric mediators i. e. specific 5-HT receptor antagonists.
Results: EFS-induced responses were sensitive to TTX and partly to atropine, indicating a major neuronal involvement and a cholinergic system. Pre-treatment with WAY100635 (a 5-HT1A receptor antagonist) and granisetron up to 10.0 µM, GR113808 (a 5-HT4 receptor antagonist), methysergide and ritanserin up to 1.0 µM, failed to modify responses to EFS inall examined tissues. In the presence of SB258585 1.0 µM (a 5-HT6 receptor antagonist) there was a trend to enhance contraction in the proximal part of the intestine and reduce contraction in the distal part. Pre-treatment with SB269970A 1.0 µM (5-HT7 receptor antagonist) induced a greater contractile response to EFS at 0.4 Hz only in the duodenum.
Conclusions: The application of 5-HT1A, 5-HT2, 5-HT3, 5-HT4, 5-HT6 and 5-HT7 receptor antagonists, applied at concentrations lower than 1.0 µM did not modify the EFS-induced contraction and relaxation responses, whichsuggests the unlikely involvement of endogenous 5-HT in mediating responses to EFS in the described test conditions.
Keywords: Electric Stimulation Therapy; Serotonin 5-HT1 Receptor Antagonists; Intestine, Smal
EGLN1 Inhibition and Rerouting of α-Ketoglutarate Suffice for Remote Ischemic Protection
Ischemic preconditioning is the phenomenon whereby brief periods of sublethal ischemia protect against a subsequent, more prolonged, ischemic insult. In remote ischemic preconditioning (RIPC), ischemia to one organ protects others organs at a distance. We created mouse models to ask if inhibition of the alpha-ketoglutarate (αKG)-dependent dioxygenase Egln1, which senses oxygen and regulates the hypoxia-inducible factor (HIF) transcription factor, could suffice to mediate local and remote ischemic preconditioning. Using somatic gene deletion and a pharmacological inhibitor, we found that inhibiting Egln1 systemically or in skeletal muscles protects mice against myocardial ischemia-reperfusion (I/R) injury. Parabiosis experiments confirmed that RIPC in this latter model was mediated by a secreted factor. Egln1 loss causes accumulation of circulating αKG, which drives hepatic production and secretion of kynurenic acid (KYNA) that is necessary and sufficient to mediate cardiac ischemic protection in this setting.Broad Institute of MIT and Harvard. SPARC ProgramBurroughs Wellcome Fun
Faculty Members’ Perceptions of Quality Assurance and Accreditation in Afghanistan
Abstract This study investigated faculty members’ perceptions of quality assurance and accreditation (QAA) in Afghanistan. The study aimed to examine how familiar faculty members were with QAA policy, quality concepts, QAA processes, and whether QAA process has improved the status quo. Through a sequential exploratory mixed methods design, the investigators interviewed seven faculty members at four universities, and subsequently conducted a self-administered survey questionnaire at six universities (two public and four private). A response rate of 54 percent (N = 42) was obtained from the survey. The study findings suggest that faculty members had mixed impressions about QAA implementation. For instance, an overall sum of mean scores shows that faculty members have a positive view about QAA processes M = 3.5 (SD = .75), however, interview participants were less satisfied with QAA outcome. Lastly, implications are made that a successful implementation of QAA processes in Afghanistan is contingent on: 1) establishment of a quality culture wherein universities own the processes and outcomes, and 2) engagement of key stakeholders including faculty, staff, and administrators to internalize QAA processes to improve the status quo. Keywords: higher education quality; quality assurance; accreditation; higher education in Afghanista
Removal of Nitrogen From Secondary Wastewater Effluent Through No 3-N Reduction Using Sulfur Dioxide (SO2)
The overall purpose of this study was to evaluate the ability of sulfur dioxide (SO2) to remove nitrate-nigrogen (i.e., reduction to a gaseous form) from the secondary wastewater effluent. To accomplish th above task, a jar test procedure was established and the concentration of NO3-N along with the concentration of NH3-N present in the secondary wastewater, treated with SO2, were measured initially and after 10 min, 20 min, 30 min, 40 min, and 24 hr. Then, the percent NO3-N removal was calculated, comparing the NO3-H concentrations measured in each treatment with the initial values. The above procedures were conducted for 36 different runs resulting from variation of the parameters which were believed to effect the kinetics of the reaction (i.e., SO2 concentration, presence of catalysts, temperature, and NO3-N concentration). Three levels of SO2 (500, 1000, 2000 mg/1), two levels of NO3-N(25-30 and 40-45 mg/1), two temperatures (20 degrees and 35 degrees Celsius), and two different catalysts (Fe+3 1 mg/1 and Feo 1 g/1) were used in this study. Prior to the jar tests, it was necessary to develop techniques to eliminate the SO2 interferences with analysis of NO2-N, and NH3-N. Two approahces were made to accomplish this task. First by air stripping of the SO2 treated secondary wastewater sample; secondly by diluting the SO2 treated secondary water to decrease the SO2 concentration to a level of less than 80 mg/1 as SO2. Satisfactory results were obtained applying both stripping and dilution methods
The Incremental Cooperative Design of Preventive Healthcare Networks
This document is the Accepted Manuscript version of the following article: Soheil Davari, 'The incremental cooperative design of preventive healthcare networks', Annals of Operations Research, first published online 27 June 2017. Under embargo. Embargo end date: 27 June 2018. The final publication is available at Springer via http://dx.doi.org/10.1007/s10479-017-2569-1.In the Preventive Healthcare Network Design Problem (PHNDP), one seeks to locate facilities in a way that the uptake of services is maximised given certain constraints such as congestion considerations. We introduce the incremental and cooperative version of the problem, IC-PHNDP for short, in which facilities are added incrementally to the network (one at a time), contributing to the service levels. We first develop a general non-linear model of this problem and then present a method to make it linear. As the problem is of a combinatorial nature, an efficient Variable Neighbourhood Search (VNS) algorithm is proposed to solve it. In order to gain insight into the problem, the computational studies were performed with randomly generated instances of different settings. Results clearly show that VNS performs well in solving IC-PHNDP with errors not more than 1.54%.Peer reviewe
Non-Invasive Brain-to-Brain Interface (BBI): Establishing Functional Links between Two Brains
Transcranial focused ultrasound (FUS) is capable of modulating the neural activity of specific brain regions, with a potential role as a non-invasive computer-to-brain interface (CBI). In conjunction with the use of brain-to-computer interface (BCI) techniques that translate brain function to generate computer commands, we investigated the feasibility of using the FUS-based CBI to non-invasively establish a functional link between the brains of different species (i.e. human and Sprague-Dawley rat), thus creating a brain-to-brain interface (BBI). The implementation was aimed to non-invasively translate the human volunteer's intention to stimulate a rat's brain motor area that is responsible for the tail movement. The volunteer initiated the intention by looking at a strobe light flicker on a computer display, and the degree of synchronization in the electroencephalographic steady-state-visual-evoked-potentials (SSVEP) with respect to the strobe frequency was analyzed using a computer. Increased signal amplitude in the SSVEP, indicating the volunteer's intention, triggered the delivery of a burst-mode FUS (350 kHz ultrasound frequency, tone burst duration of 0.5 ms, pulse repetition frequency of 1 kHz, given for 300 msec duration) to excite the motor area of an anesthetized rat transcranially. The successful excitation subsequently elicited the tail movement, which was detected by a motion sensor. The interface was achieved at 94.0 +/- 3.0% accuracy, with a time delay of 1.59 +/- 1.07 sec from the thought-initiation to the creation of the tail movement. Our results demonstrate the feasibility of a computer-mediated BBI that links central neural functions between two biological entities, which may confer unexplored opportunities in the study of neuroscience with potential implications for therapeutic applications.open12
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Preclinical mouse models of immune checkpoint inhibitor-associated myocarditis
In this Review, we present a comprehensive analysis of preclinical models used to study immune checkpoint inhibitor-associated myocarditis (hereafter ICI-myocarditis), a potentially lethal immune-related adverse event. We begin by providing an overview of immune checkpoint inhibitors, highlighting how their efficacy in cancer treatment is counterbalanced by their predisposition to cause immune-related adverse events. Next, we draw from human data to identify disease features that an effective mouse model should ideally mimic. After that, we present a critical evaluation of a wide variety of existing mouse models including genetic, pharmacological and humanized models. We summarize insights gathered about the underlying mechanisms of ICI-myocarditis and the role of mouse models in these discoveries. We conclude with a perspective on the future of preclinical models, highlighting potential model improvements and research directions that could strengthen our understanding of ICI-myocarditis, ultimately improving patient outcomes
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