113 research outputs found
Exploring the Similarities of the dS/CFT and Ads/CFT Correspondences
The dS/CFT correspondence differs from its AdS/CFT counterpart in some ways,
yet is strikingly similar to it in many others. For example, both involve CFTs
defined on connected spaces (despite the fact that the conformal boundary of
deSitter space is not connected), and both impose constraints on scalar masses
(Strominger's bound for deSitter, and the Breitenlohner-Freedman bound for
Anti-deSitter). We argue that these similarities can be explored and exploited
using a slight extension of the Euclidean approach to AdS/CFT. The methods are
particularly compatible with Hull's embedding of deSitter Space in a timelike
T-dual version of M-theory.Comment: Typos fixed, minor clarification
Improving material flow by developing new warehouse layout
Our group was tasked to develop a facility layout for Duncan Ticking's new warehouse and determine appropriate shelving as well as material handling equipment. Duncan Ticking is a reseller of textiles and currently operates two warehouses in Fort Worth. Both are currently full of inventory. The company purchases ticking from international suppliers and resells them to domestic manufacturers. Demand is forecast for products they import based on sales history. As customers change styles and patterns, some products no longer sell at the same volumes, and they are left with the balance to try and sell elsewhere. The company plans to build a new warehouse adjacent to two existing ones, hoping to relieve some of the congestion and to improve the storage and flow of goods. The reseller is seeking assistance to design a facility layout for the additional warehouse. The goal of the project is to develop three recommendations for the proper shelving and supporting material handling processes and devices along with corresponding layouts. A cost-benefit analysis of each of the alternatives will be developed and presented to the client. The primary objectives are to minimize the travel of material and personnel within the warehouse and ensure that the incoming and outgoing orders are processed efficiently and effectively. Time permitting, an inventory analysis will also be conducted throughout the current warehouses along with a plan to implement new storage policies, disposal of unused equipment and materials for more than three years old, along with a cost-benefit analysis of our recommendations
The dS/CFT Correspondence and the Big Smash
Recent observations suggest that the cosmological equation-of-state parameter
w is close to -1. To say this is to imply that w could be slightly less than
-1, which leads to R.Caldwell's "Phantom cosmologies". These often have the
property that they end in a "Big Smash", a final singularity in which the
Universe is destroyed in a finite proper time by excessive *expansion*. We show
that, classically, this fate is not inevitable: there exist Smash-free Phantom
cosmologies, obtained by a suitable perturbation of the deSitter equation of
state, in which the spacetime is in fact asymptotically deSitter. [Contrary to
popular belief, such cosmologies, which violate the Dominant Energy Condition,
do not necessarily violate causality.] We also argue, however, that the
physical interpretation of these classically acceptable spacetimes is radically
altered by ``holography'', as manifested in the dS/CFT correspondence. It is
shown that, if the boundary CFTs have conventional properties, then recent
ideas on "time as an inverse renormalization group flow" can be used to rule
out these cosmologies. Very recently, however, it has been argued that the CFTs
in dS/CFT are of a radically unconventional form, and this opens up the
possibility that Smash-free Phantom spacetimes offer a simple model of a
"bouncing" cosmology in which the quantum-mechanical entanglement of the field
theories in the infinite past and future plays an essential role.Comment: 22 pages, clarification of triple analytic continuation, additional
Comments added in the light of hep-th/020724
First Isolation of West Nile virus from a Patient with Encephalitis in the United States
West Nile virus (WNV) was isolated from a patient who developed encephalitis while undergoing treatment with CHOP (cyclophosphamide, hydroxydoxorubicin, vincristine [Oncovin], predisone) and rituximab for a non-Hodgkin B-cell lymphoma. Both standard reverse transcriptionāpolymerase chain reaction (RT-PCR) and Taqman RT-PCR established the diagnosis of WNV infection from cerebrospinal fluid (CSF). Several whole blood samples and one serum sample underwent further testing. CSF and serum samples were negative for WNV antibody; however, all samples were positive by both RT-PCR assays. Infectious virus was recovered from a blood sample, and its identity was confirmed by using a WNV-specific immunofluorescence assay. The complete WNV genomes determined from CSF and from the virus isolate adapted from cell culture were the same. The results represent the first complete WNV genome sequence obtained directly from human CSF and the first time that infectious WNV has been recovered from a patient with encephalitis in North America
Diagnosis of a severe congenital anomaly: a qualitative analysis of parental decision-making and the implications for healthcare encounters.
Objective: To explore parental decision making following diagnosis of a severe congenital anomaly, and implications for healthcare encounters. Design: Qualitative semi-structured interviews with 38 parents-to- be were collated and triangulated with data generated from consultation recordings. Analysis: Data were analysed using a constant comparative-based approach. Setting: Recruitment was undertaken across four fetal medicine sites in two tertiary referral trusts. Participants: Parents-to- be whose pregnancy was suspected or diagnosed as being affected by a severe congenital anomaly. This sample was purposive to include known factors affecting the decision to terminate or continue the affected pregnancy. Findings: In trying to make a decision about how to proceed with their pregnancy, parents-to-be typically had to work hard to negotiate multiple uncertainties around the diagnosis and prognosis of the suspected anomaly. This was influenced by parentsā capacity to cope with uncertainty and the way in which uncertainty was managed by the clinical team. This negotiation of uncertainty was enacted within a fluid, nonlinear three-phase process: āinformation seeking,ā reflecting the way parents-to-be face the uncertainty associated with a fetal diagnosis and associated prognosis; āimplications,ā where consideration is given to future consequences of the decision; and ādecision making,ā which reflects the way in which the decision is made (head-or heart-led). Spectrums of responses were apparent within each phase. Conclusions: This study provides important insights into how parents-to- be make decisions following diagnosis or suspicion of a severe congenital anomaly. The impact of these on healthcare encounters is discussed, alongside recommendations for clinical practice
Living standards and plague in London, 1560ā1665
This article uses individual records of 930,000 burials and 630,000 baptisms to reconstruct the spatial and temporal patterns of birth and death in London from 1560 to 1665, a period dominated by recurrent plague. The plagues of 1563, 1603, 1625, and 1665 appear of roughly equal magnitude, with deaths running at five to six times their usual rate, but the impact on wealthier central parishes falls markedly through time. Tracking the weekly spread of plague, we find no evidence that plague emerged first in the docks, and in many cases elevated mortality emerges first in the poor northern suburbs. Looking at the seasonal pattern of mortality, we find that the characteristic autumn spike associated with plague continued into the early 1700s. Natural increase improved as smaller crises disappeared after 1590, but fewer than half of those born survived childhood
A rehabilitation intervention to promote physical recovery following intensive care: a detailed description of construct development, rationale and content together with proposed taxonomy to capture processes in a randomised controlled trial.
Background: increasing numbers of patients are surviving critical illness, but survival may be associated with aconstellation of physical and psychological sequelae that can cause on going disability and reduced health-relatedquality of life. Limited evidence currently exists to guide the optimum structure, timing, and content of rehabilitationprogrammes. There is a need to both develop and evaluate interventions to support and expedite recovery during the post-ICU discharge period. This paper describes the construct development for a complex rehabilitationintervention intended to promote physical recovery following critical illness. The intervention is currently beingevaluated in a randomised trial (ISRCTN09412438; funder Chief Scientists Office, Scotland).Methods: the intervention was developed using the Medical Research Council (MRC) framework for developingcomplex healthcare interventions. We ensured representation from a wide variety of stakeholders includingcontent experts from multiple specialties, methodologists, and patient representation. The intervention constructwas initially based on literature review, local observational and audit work, qualitative studies with ICU survivors,and brainstorming activities. Iterative refinement was aided by the publication of a National Institute for Healthand Care Excellence guideline (No. 83), publicly available patient stories (Healthtalkonline), a stakeholder event incollaboration with the James Lind Alliance, and local piloting. Modelling and further work involved a feasibility trial and development of a novel generic rehabilitation assistant (GRA) role. Several rounds of external peer review during successive funding applications also contributed to development.Results: the final construct for the complex intervention involved a dedicated GRA trained to pre-definedcompetencies across multiple rehabilitation domains (physiotherapy, dietetics, occupational therapy, and speech/language therapy), with specific training in post-critical illness issues. The intervention was from ICU discharge to 3 months post-discharge, including inpatient and post-hospital discharge elements. Clear strategies to provide information to patients/families were included. A detailed taxonomy was developed to define and describe the processes undertaken, and capture them during the trial. The detailed process measure description, together with a range of patient, health service, and economic outcomes were successfully mapped on to the modifiedCONSORT recommendations for reporting non-pharmacologic trial interventions.Conclusions: the MRC complex intervention framework was an effective guide to developing a novel post-ICUrehabilitation intervention. Combining a clearly defined new healthcare role with a detailed taxonomy of process and activity enabled the intervention to be clearly described for the purpose of trial delivery and reporting. These data will be useful when interpreting the results of the randomised trial, will increase internal and external trial validity, and help others implement the intervention if the intervention proves clinically and cost effective
An evidence base to optimise methods for involving patient and public contributors in clinical trials: a mixed-methods study
BACKGROUND: In comparison with other study designs, randomised trials are regarded as particularly likely to benefit from patient and public involvement (PPI). Using mixed-methods research we investigated PPI from the perspectives of researchers and PPI contributors. METHODS: Randomised trials in receipt of funding from the Health Technology Assessment (HTA) programme between 2006 and 2010 were identified. Funding applications and board and referee comments were obtained and data relevant to PPI extracted. Chief investigators (CIs), PPI contributors and UK Clinical Research Collaboration Registered Clinical Trials Units (RCTUs) were surveyed. Interviews were conducted with researchers and PPI contributors. RESULTS: A total of 111 trials were included. Text relevant to PPI was identified in half of the trials for which the first-stage applications were available, but only one-quarter described PPI within their development. In the second stage of the application, the majority provided some text relevant to PPI, with over half having PPI in their development. Fewer than half of referees commented on PPI, and funding boards rarely provided comments in relation to PPI. Seventy-three per cent (81 of 111) of CIs responded to the survey and 98% (79 of 81) included PPI at some stage in their trial. CIs considered high impact from PPI contributors to occur more frequently in trial setup, with low or no impact being more common during trial conduct, analysis and dissemination. Only one-third of CIs provided PPI contributor contact details but all contributors contacted completed the survey. The majority of contributors felt engaged and valued by the research team. Interviews were conducted with researchers and/or PPI contributors for 28 trials identifying two main influences on perception of PPI impact: whether or not CIs expressed personal goals and plans for PPI; and the quality of their relationship with the PPI contributors. The importance of early engagement was identified, with opportunity for input thereafter limited. Three PPI roles were identified: oversight, managerial and responsive. Oversight roles, as required by funders, were associated with low impact in comparison with responsive or managerial roles. Most researchers could see some value in PPI training for researchers, although those that had received such training themselves expressed concerns about its purpose and evidence base. Training for PPI contributors was considered unnecessary, with conversational approaches preferred, although this did not appear to provide an opportunity for role negotiation. The RCTU survey response rate was 85% (39 of 46). The majority (37 of 39) reported PPI within trials co-ordinated by their unit. Trial characteristics were used by half to determine the approach to PPI. Two-thirds reported recent developments or changes in implementing plans for PPI (21 of 33). Support to PPI contributors was commonly offered through members of staff at the unit. CONCLUSIONS: PPI is occurring in the majority of trials funded by the HTA programme, but uncertainty remains about how it is assessed and valued. Early involvement, building a relationship between researchers and contributors, responsive or managerial roles, and having defined goals for PPI were associated with impact. Efficiency could be gained by utilising the RCTU network to identify and tackle challenges, and develop a risk-based approach utilising trial characteristics. Recommendations are made to trial funders and the research community. Given the difficulties for some informants in recalling PPI contributions, future research using a prospective approach would be valuable. Ethnographic research that combines observation and multi-informant interviews is likely to be informative in identifying impact. The research community needs to give further consideration to processes for selecting PPI contributors and models of implementing PPI
Can We Modify the Intrauterine Environment to Halt the Intergenerational Cycle of Obesity?
Child obesity is a global epidemic whose development is rooted in complex and multi-factorial interactions. Once established, obesity is difficult to reverse and epidemiological, animal model, and experimental studies have provided strong evidence implicating the intrauterine environment in downstream obesity. This review focuses on the interplay between maternal obesity, gestational weight gain and lifestyle behaviours, which may act independently or in combination, to perpetuate the intergenerational cycle of obesity. The gestational period, is a crucial time of growth, development and physiological change in mother and child. This provides a window of opportunity for intervention via maternal nutrition and/or physical activity that may induce beneficial physiological alternations in the fetus that are mediated through favourable adaptations to in utero environmental stimuli. Evidence in the emerging field of epigenetics suggests that chronic, sub-clinical perturbations during pregnancy may affect fetal phenotype and long-term human data from ongoing randomized controlled trials will further aid in establishing the science behind ones predisposition to positive energy balance
Sound to Language: Different Cortical Processing for First and Second Languages in Elementary School Children as Revealed by a Large-Scale Study Using fNIRS
A large-scale study of 484 elementary school children (6ā10 years) performing word repetition tasks in their native language (L1-Japanese) and a second language (L2-English) was conducted using functional near-infrared spectroscopy. Three factors presumably associated with cortical activation, language (L1/L2), word frequency (high/low), and hemisphere (left/right), were investigated. L1 words elicited significantly greater brain activation than L2 words, regardless of semantic knowledge, particularly in the superior/middle temporal and inferior parietal regions (angular/supramarginal gyri). The greater L1-elicited activation in these regions suggests that they are phonological loci, reflecting processes tuned to the phonology of the native language, while phonologically unfamiliar L2 words were processed like nonword auditory stimuli. The activation was bilateral in the auditory and superior/middle temporal regions. Hemispheric asymmetry was observed in the inferior frontal region (right dominant), and in the inferior parietal region with interactions: low-frequency words elicited more right-hemispheric activation (particularly in the supramarginal gyrus), while high-frequency words elicited more left-hemispheric activation (particularly in the angular gyrus). The present results reveal the strong involvement of a bilateral language network in childrenās brains depending more on right-hemispheric processing while acquiring unfamiliar/low-frequency words. A right-to-left shift in laterality should occur in the inferior parietal region, as lexical knowledge increases irrespective of language
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