161 research outputs found
Exotic fluids and crystals of soft polymeric colloids
We discuss recent developments and present new findings in the colloidal
description of soft polymeric macromolecular aggregates. For various
macromolecular architectures, such as linear chains, star polymers, dendrimers
and polyelectrolyte stars, the effective interactions between suitably chosen
coordinates are shown to be ultrasoft, i.e., they either remain finite or
diverge very slowly at zero separation. As a consequence, the fluid phases have
unusual characteristics, including anomalous pair correlations and mean-field
like thermodynamic behaviour. The solid phases can exhibit exotic, strongly
anisotropic as well as open crystal structures. For example, the diamond and
the A15-phase are shown to be stable at sufficiently high concentrations.
Reentrant melting and clustering transitions are additional features displayed
by such systems, resulting in phase diagrams with a very rich topology. We
emphasise that many of these effects are fundamentally different from the usual
archetypal hard sphere paradigm. Instead, we propose that these fluids fall
into the class of mean-field fluids.Comment: 22 pages, uses iopart.cls and iopart10.clo; submitted to Journal of
Physics Condensed Matter, special issue in honour of professor Peter Puse
Interventions to promote oral nutritional behaviours in people living with neurodegenerative disorders of the motor system : a systematic review
Background & Aims:
Weight loss is common in people with neurodegenerative diseases of the motor system (NDMS), such as Parkinsonâs disease and Amyotrophic Lateral Sclerosis, and is associated
with reduced quality of life, functional ability and survival. This systematic review aims to identify interventions and intervention components (i.e. behaviour change techniques [BCTs] and modes of delivery [MoDs]) that are associated with increased effectiveness in promoting oral nutritional behaviours that help people with NDMS to achieve a high-calorie diet.
Methods:
Eight electronic databases including MEDLINE and CINAHL were searched from inception to May 2018. All interventions from included studies were coded for relevant BCTs and MoDs. Methodological quality of studies was assessed using the Cochrane risk of bias tool.
Results:
Fourteen studies were included. Of these, eight studies reported interventions to assist with swallowing difficulties and six studies reported interventions targeting dietary content.
Beneficial effects in managing swallowing difficulties were observed with video assisted swallowing therapy, lung volume recruitment and swallowing management clinics with
outpatient support. In contrast, studies reporting effectiveness of chin down posture, use of thickened liquids and respiratory muscle training were inconclusive. Positive effects in
interventions targeting dietary content included the use of food pyramid tools, individualised nutritional advice with nutritional interventions, electronic health applications, face-to-face
dietary counselling and high fat, high carbohydrate and milk whey protein supplements. Individualised nutritional advice with weekly phone contact did not appear to be effective.
Most frequently coded BCTs were âinstructions on how to perform the behaviourâ, âself-monitoringâ and âbehavioural practice/rehearsalâ. Most commonly identified MoDs were âhumanâ, âface-to-faceâ and âsomatic therapyâ. However, the robustness of these findings are low due to small number of studies, small sample sizes and large between-study variability.
Conclusions:
Despite the limited evidence, these findings may help inform the development of more effective interventions to promote oral nutritional behaviours in people with NDMS. However, further research is needed to demonstrate which interventions, or intervention components, yield most benefit
PEARLS: A Potentially Isolated Quiescent Dwarf Galaxy with a TRGB Distance of 31 Mpc
A wealth of observations have long suggested that the vast majority of
isolated classical dwarf galaxies (- M) are currently
star-forming. However, recent observations of the large abundance of
"Ultra-Diffuse Galaxies" beyond the reach of previous large spectroscopic
surveys suggest that our understanding of the dwarf galaxy population may be
incomplete. Here we report the serendipitous discovery of an isolated quiescent
dwarf galaxy in the nearby Universe, which was imaged as part of the PEARLS GTO
program. Remarkably, individual red-giant branch stars are visible in this
near-IR imaging, suggesting a distance of Mpc, and a wealth of archival
photometry point to an sSFR of yr. Spectra obtained
with the Lowell Discovery Telescope find a recessional velocity consistent with
the Hubble Flow and km/s separated from the nearest massive galaxy in
SDSS, suggesting that this galaxy was either quenched from internal mechanisms
or had a very high-velocity interaction with a nearby massive galaxy in the
past. This analysis highlights the possibility that many nearby quiescent dwarf
galaxies are waiting to be discovered and that JWST has the potential to
identify them.Comment: Submitted to ApJ Letters. Comments welcome
Health risk behaviours among adolescents in the English-speaking Caribbean: a review
<p>Abstract</p> <p>Background</p> <p>The aim of this paper was to review and summarize research on prevalence of health risk behaviours, their outcomes as well as risk and protective factors among adolescents in the English-speaking Caribbean.</p> <p>Methods</p> <p>Searching of online databases and the World Wide Web as well as hand searching of the <it>West Indian Medical Journal </it>were conducted. Papers on research done on adolescents aged 10 â 19 years old and published during the period 1980 â 2005 were included.</p> <p>Results</p> <p>Ninety-five relevant papers were located. Five papers were published in the 1980s, 47 in the 1990s, and from 2000â2005, 43 papers. Health risk behaviours and outcomes were divided into seven themes. Prevalence data obtained for these, included lifetime prevalence of <b>substance use</b>: cigarettes-24% and marijuana-17%; <b>high risk sexual behaviour</b>: initiation of sexual activity †10 years old-19% and those having more than six partners-19%; <b>teenage pregnancy</b>: teens account for 15â20% of all pregnancies and one-fifth of these teens were in their second pregnancy; <b>Sexually-Transmitted Infections (STIs)</b>: population prevalence of gonorrhoea and/or chlamydia in 18â21 year-olds was 26%; <b>mental health</b>: severe depression in the adolescent age group was 9%, and attempted suicide-12%; <b>violence and juvenile delinquency</b>: carrying a weapon to school in the last 30 days-10% and almost always wanting to kill or injure someone-5%; <b>eating disorders and obesity</b>: overweight-11%, and obesity-7%. Many of the risk behaviours in adolescents were shown to be related to the adolescent's family of origin, home environment and parent-child relationships. Also, the protective effects of family and school connectedness as well as increased religiosity noted in studies from the United States were also applicable in the Caribbean.</p> <p>Conclusion</p> <p>There is a substantial body of literature on Caribbean adolescents documenting prevalence and correlates of health risk behaviours. Future research should emphasize the designing and testing of interventions to alleviate this burden.</p
Targeted Next-Generation Sequencing Analysis of 1,000 Individuals with Intellectual Disability.
To identify genetic causes of intellectual disability (ID), we screened a cohort of 986 individuals with moderate to severe ID for variants in 565 known or candidate ID-associated genes using targeted next-generation sequencing. Likely pathogenic rare variants were found in âŒ11% of the cases (113 variants in 107/986 individuals: âŒ8% of the individuals had a likely pathogenic loss-of-function [LoF] variant, whereas âŒ3% had a known pathogenic missense variant). Variants in SETD5, ATRX, CUL4B, MECP2, and ARID1B were the most common causes of ID. This study assessed the value of sequencing a cohort of probands to provide a molecular diagnosis of ID, without the availability of DNA from both parents for de novo sequence analysis. This modeling is clinically relevant as 28% of all UK families with dependent children are single parent households. In conclusion, to diagnose patients with ID in the absence of parental DNA, we recommend investigation of all LoF variants in known genes that cause ID and assessment of a limited list of proven pathogenic missense variants in these genes. This will provide 11% additional diagnostic yield beyond the 10%-15% yield from array CGH alone.Action Medical Research (SP4640); the Birth Defect Foundation (RG45448); the Cambridge National Institute for Health Research Biomedical Research Centre (RG64219); the NIHR Rare Diseases BioResource (RBAG163); Wellcome Trust award WT091310; The Cell lines and DNA bank of Rett Syndrome, X-linked mental retardation and other genetic diseases (member of the Telethon Network of Genetic Biobanks (project no. GTB12001); the Genetic Origins of Congenital Heart Disease Study (GO-CHD)- funded by British Heart Foundation (BHF)This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/humu.2290
Developing "personality" taxonomies: Metatheoretical and methodological rationales underlying selection approaches, methods of data generation and reduction principles
Taxonomic "personality" models are widely used in research and applied fields. This article applies the Transdisciplinary Philosophy-of-Science Paradigm for Research on Individuals (TPS-Paradigm) to scrutinise the three methodological steps that are required for developing comprehensive âpersonalityâ taxonomies: 1) the approaches used to select the phenomena and events to be studied, 2) the methods used to generate data about the selected phenomena and events and 3) the reduction principles used to extract the âmost importantâ individual-specific variations for constructing âpersonalityâ taxonomies. Analyses of some currently popular taxonomies reveal frequent mismatches between the researchersâ explicit and implicit metatheories about âpersonalityâ and the abilities of previous methodologies to capture the particular kinds of phenomena toward which they are targeted. Serious deficiencies that preclude scientific quantifications are identified in standardised questionnaires, psychologyâs established standard method of investigation. These mismatches and deficiencies derive from the lack of an explicit formulation and critical reflection on the philosophical and metatheoretical assumptions being made by scientists and from the established practice of radically matching the methodological tools to researchersâ preconceived ideas and to pre-existing statistical theories rather than to the particular phenomena and individuals under study. These findings raise serious doubts about the ability of previous taxonomies to appropriately and comprehensively reflect the phenomena towards which they are targeted and the structures of individual-specificity occurring in them. The article elaborates and illustrates with empirical examples methodological principles that allow researchers to appropriately meet the metatheoretical requirements and that are suitable for comprehensively exploring individualsâ âpersonalityâ
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