Transition state theory and the dynamics of hard disks

The dynamics of two and five disk systems confined in a square has been studied using molecular dynamics simulations and compared with the predictions of transition state theory. We determine the partition functions Z and Z^\ddagger of transition state theory using a procedure first used by Salsburg and Wood for the pressure. Our simulations show this procedure and transition state theory are in excellent agreement with the simulations. A generalization of the transition state theory to the case of a large number of disks N is made and shown to be in full agreement with simulations of disks moving in a narrow channel. The same procedure for hard spheres in three dimensions leads to the Vogel-Fulcher-Tammann formula for their alpha relaxation time.Comment: 1 new author, new simulations and figures, less speculation. Now 6 pages, 6 figures, 1 animation. Animation may be viewed at http://www.theory.physics.manchester.ac.uk/~godfrey/supplement/activated_dynamics2.htm

Analysis of motion parameter variations for rotorcraft flight simulators

No standard guidelines currently exist for tuning rotorcraft flight simulation motion platforms. This often leads to systems that are poorly utilized. This paper presents results from a study to determine the influence of parameter variations in two rotorcraft research simulators. Investigations were conducted using three Mission Task Elements (MTEs), and both subjective and objective analysis is used to determine the suitability of motion settings. Motion settings are compared with recommended Objective Motion Cueing Test (OMCT) boundaries for fixed-wing aircraft. Results show differences in the fidelity of motion settings, and recommendations specifically for rotorcraft simulation are presented

An electrically driven, computer controlled robotics platform for orchard use

As automation in agriculture progresses, more automation systems will be placed into farms & orchards. Systems that service the crops directly are likely to have positioning requirements that make traditional tractor-trailer units unsuitable. This paper introduces a platform built for transporting robotics modules through a kiwifruit orchard. Performance figures, design considerations and a general hardware overview are presented. The platform is controlled either by remote or computer generated drive commands - facilitating autonomous navigation. In-orchard testing shows the system is well suited for the target application, achieving stable speed control and repeatable positioning

Randomized double-blind placebo-controlled trial of 40 mg/day of atorvastatin in reducing the severity of sepsis in ward patients (ASEPSIS Trial)

Introduction: Several observational studies suggest that statins modulate the pathophysiology of sepsis and may prevent its progression. The aim of this study was to determine if the acute administration of atorvastatin reduces sepsis progression in statin naïve patients hospitalized with sepsis. Methods: A single centre phase II randomized double-blind placebo-controlled trial. Patients with sepsis were randomized to atorvastatin 40 mg daily or placebo for the duration of their hospital stay up to a maximum of 28-days. The primary end-point was the rate of sepsis progressing to severe sepsis during hospitalization. Results: 100 patients were randomized, 49 to the treatment with atorvastatin and 51 to placebo. Patients in the atorvastatin group had a significantly lower conversion rate to severe sepsis compared to placebo (4% vs. 24% p = 0.007.), with a number needed to treat of 5. No significant difference in length of hospital stay, critical care unit admissions, 28-day and 12-month readmissions or mortality was observed. Plasma cholesterol and albumin creatinine ratios were significantly lower at day 4 in the atorvastatin group (p < 0.0001 and p = 0.049 respectively). No difference in adverse events between the two groups was observed (p = 0.238). Conclusions: Acute administration of atorvastatin in patients with sepsis may prevent sepsis progression. Further multi-centre trials are required to verify these findings. Trial Registration: International Standard Randomized Control Trial Registry ISRCTN64637517

Cognitive profiles in childhood and adolescence differ between adult psychotic and affective symptoms: a prospective birth cohort study

Background Differences between verbal and non-verbal cognitive development from childhood to adulthood may differentiate between those with and without psychotic symptoms and affective symptoms in later life. However, there has been no study exploring this in a population-based cohort. Method The sample was drawn from the MRC National Survey of Health and Development, and consisted of 2,384 study members with self-reported psychotic experiences and affective symptoms at age 53 years, and with complete cognitive data at ages 8 and 15 years. The association between verbal and non-verbal cognition at age 8 years and relative developmental lag from age 8 to 15 years, and both adult outcomes were tested with the covariates adjusted, and mutually adjusted for verbal and nonverbal cognition. Results Those with psychotic experiences (thought interference [n=433], strange experience [n=296], hallucination [n=88]) had lower cognition at both age 8 and 15 years in both verbal and non-verbal domains. After mutual adjustment, lower verbal cognition at age 8 years and greater verbal developmental lag were associated with higher likelihood of psychotic experiences within individuals, whereas there was no association between non-verbal cognition and any psychotic experience. In contrast, those with case-level affective symptoms (n=453) had lower non-verbal cognition at age 15, and greater developmental lag in non-verbal domain. After adjustment, lower non-verbal cognition at age 8 years and greater non-verbal developmental lag were associated with higher risk of case-level affective symptoms within individuals. Conclusions These results suggest that cognitive profiles in childhood and adolescence differentiate psychiatric disease spectra.SK was supported by the grants from JSPS KAKENHI Grant Number 25870143, 26118703, and Strategic Young Researcher Overseas Visits Program for Accelerating Brain Circulation. MR is funded by the UK Medical Research Council [Unit Programme numbers MC UU 12019/3]. PJ is supported by Wellcome Trust grants 095844/Z/11/Z and 088869/Z/09/Z; National Institute for Health Research grant RP-PG-0606-1335; and by the NIHR Cambridge BRC and the NIHR CLAHRC East of England

Adolescent self-control predicts midlife hallucinatory experiences:40-year follow-up of a national birth cohort

Associations between self-control in adolescence and adult mental health are unclear in the general population; to our knowledge, no study has investigated self-control in relation to psychotic-like symptoms

The Relative Importance of Different Trophic Pathways for Secondary Exposure to Anticoagulant Rodenticides

Secondary exposure of predators to anticoagulant rodenticides, and in particular second generation anticoagulant rodenticides (SGARs), is a global phenomenon. The widespread and large-scale nature of this exposure has attracted considerable concern, although the consequences in terms of likelihood of poisoning of individuals and resultant impacts on populations are not well characterised. Secondary exposure of predators may as rise from once or more of: (i) eating contaminated commensal rodents subject to control (target species are typically rats and house mice); (ii) consumption of contaminated non-target small mammals (such as Peromyscus, Microtus, and Apodemus species) that encounter and feed on what are rodent-attractive baits; (iii) consumption of non-rodent vertebrate and invertebrate prey that may also incidentally encounter and eat baits. We hypothesised that predators feeding primarily on target species may be most at risk of exposure to SGARs while those predominantly taking non-mammalian prey may be at least risk. We tested this hypothesis by comparing exposure, determined from the presence and magnitude of SGAR liver residues, in red kites (Milvus milvus), which feeds extensively on rats, in barn owls (Tyto alba), kestrels (Falco tinnunculus), and tawny owls (Strix aluco) that feed widely on non-target small mammals, and in sparrowhawks (Accipiter nisus) that feed predominantly on small birds. We found that the scale and magnitude of exposure was broadly consistent with our hypothesis, and that controlling for age in the analysis could be important as older birds can accumulate residues with age. However, exposure in kestrels was typically greater than that in barn owls and tawny owls, despite what is thought to be a general similarity among the species in their diets. We discuss the relative importance of trophic pathways relative to other factors that may drive secondary exposure in predators, and confirm that species that feed on rats or other target species may be at most risk of exposure and poisoning

Avatars of Eurocentrism in the critique of the liberal peace

Recent scholarly critiques of the so-called liberal peace raise important political and ethical challenges to practices of postwar intervention in the global South. However, their conceptual and analytic approaches have tended to reproduce rather than challenge the intellectual Eurocentrism underpinning the liberal peace. Eurocentric features of the critiques include the methodological bypassing of target subjects in research, the analytic bypassing of subjects through frameworks of governmentality, the assumed ontological split between the ‘liberal’ and the ‘local’, and a nostalgia for the liberal subject and the liberal social contract as alternative bases for politics. These collectively produce a ‘paradox of liberalism’ that sees the liberal peace as oppressive but also the only true source of emancipation. However, the article suggests that a repoliticization of colonial difference offers an alternative ‘decolonizing’ approach to critical analysis through repositioning the analytic gaze. Three alternative research strategies for critical analysis are briefly developed

Analytic Perturbation Theory: A New Approach to the Analytic Continuation of the Strong Coupling Constant αS\alpha_S into the Timelike Region

The renormalization group applied to perturbation theory is ordinarily used to define the running coupling constant in the spacelike region. However, to describe processes with timelike momenta transfers, it is important to have a self-consistent determination of the running coupling constant in the timelike region. The technique called analytic perturbation theory (APT) allows a consistent determination of this running coupling constant. The results are found to disagree significantly with those obtained in the standard perturbative approach. Comparison between the standard approach and APT is carried out to two loops, and threshold matching in APT is applied in the timelike region.Comment: 16 pages, REVTeX, 7 postscript figure

Improvement and decline of cognitive function in schizophrenia over one year: a longitudinal investigation using latent growth modelling.

BACKGROUND: Long-term follow-up studies of people with schizophrenia report stability of cognitive performance; less is known about any shorter-term changes in cognitive function. METHODS: This longitudinal study aimed to establish whether there was stability, improvement or decline in memory and executive functions over four assessments undertaken prospectively in one year. Cognitive performance was assessed during randomized controlled trials of first- and second-generation antipsychotic medication. Analyses used a latent growth modeling approach, so that individuals who missed some testing occasions could be included and trajectories of cognitive change explored despite missing data. RESULTS: Over the year there was significant decline in spatial recognition but no change in pattern recognition or motor speed. Improvement was seen in planning and spatial working memory tasks; this may reflect improved strategy use with practice. There were significant individual differences in the initial level of performance on all tasks but not in rate of change; the latter may have been due to sample size limitations. Age, sex, premorbid IQ and drug class allocation explained significant variation in level of performance but could not predict change. Patients randomized to first-generation drugs improved more quickly than other groups on the planning task. CONCLUSION: We conclude that cognitive change is present in schizophrenia but the magnitude of change is small when compared with the large differences in cognitive function that exist between patients. Analyses that retain patients who drop out of longitudinal studies, as well as those who complete testing protocols, are important to our understanding of cognition in schizophrenia.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are