1,060 research outputs found
Hierarchy Theory of Evolution and the Extended Evolutionary Synthesis: Some Epistemic Bridges, Some Conceptual Rifts
Contemporary evolutionary biology comprises a plural landscape of multiple co-existent conceptual frameworks and strenuous voices that disagree on the nature and scope of evolutionary theory. Since the mid-eighties, some of these conceptual frameworks have denounced the ontologies of the Modern Synthesis and of the updated Standard Theory of Evolution as unfinished or even flawed. In this paper, we analyze and compare two of those conceptual frameworks, namely Niles Eldredge’s Hierarchy Theory of Evolution (with its extended ontology of evolutionary entities) and the Extended Evolutionary Synthesis (with its proposal of an extended ontology of evolutionary processes), in an attempt to map some epistemic bridges (e.g. compatible views of causation; niche construction) and some conceptual rifts (e.g. extra-genetic inheritance; different perspectives on macroevolution; contrasting standpoints held in the “externalism–internalism” debate) that exist between them. This paper seeks to encourage theoretical, philosophical and historiographical discussions about pluralism or the possible unification of contemporary evolutionary biology
Maternal nutritional status, food intake and pregnancy weight gain in Nepal
This is the author's accepted version (version 2) of an article published by SAGE in Journal of Health Management, March 2016. The published version is available at http://pss.sagepub.com/lookup/doi/10.1177/0972063415625537Poor maternal nutrition during pregnancy may predispose to intrauterine growth restriction (IUGR), immunological and metabolic adaptations which manifest as low birth weight and increase the risk of adult non-communicable disease. This study examined the relationships between maternal nutritional status, food intake and pregnancy weight gain (PWG) which may account for risk of low birth weight (LBW) in Nepal
Stable vortex and dipole vector solitons in a saturable nonlinear medium
We study both analytically and numerically the existence, uniqueness, and
stability of vortex and dipole vector solitons in a saturable nonlinear medium
in (2+1) dimensions. We construct perturbation series expansions for the vortex
and dipole vector solitons near the bifurcation point where the vortex and
dipole components are small. We show that both solutions uniquely bifurcate
from the same bifurcation point. We also prove that both vortex and dipole
vector solitons are linearly stable in the neighborhood of the bifurcation
point. Far from the bifurcation point, the family of vortex solitons becomes
linearly unstable via oscillatory instabilities, while the family of dipole
solitons remains stable in the entire domain of existence. In addition, we show
that an unstable vortex soliton breaks up either into a rotating dipole soliton
or into two rotating fundamental solitons.Comment: To appear in Phys. Rev.
Zinc intake, status and indices of cognitive function in adults and children: a systematic review and meta-analysis
In developing countries, deficiencies of micronutrients are thought to have a major impact on child development; however, a consensus on the specific relationship between dietary zinc intake and cognitive function remains elusive. The aim of this systematic review was to examine the relationship between zinc intake, status and indices of cognitive function in children and adults. A systematic literature search was conducted using EMBASE, MEDLINE and Cochrane Library databases from inception to March 2014. Included studies were those that supplied zinc as supplements or measured dietary zinc intake. A meta-analysis of the extracted data was performed where sufficient data were available. Of all of the potentially relevant papers, 18 studies met the inclusion criteria, 12 of which were randomised controlled trials (RCTs; 11 in children and 1 in adults) and 6 were observational studies (2 in children and 4 in adults). Nine of the 18 studies reported a positive association between zinc intake or status with one or more measure of cognitive function. Meta-analysis of data from the adult’s studies was not possible because of limited number of studies. A meta-analysis of data from the six RCTs conducted in children revealed that there was no significant overall effect of zinc intake on any indices of cognitive function: intelligence, standard mean difference of <0.001 (95% confidence interval (CI) –0.12, 0.13) P=0.95; executive function, standard mean difference of 0.08 (95% CI, –0.06, 022) P=0.26; and motor skills standard mean difference of 0.11 (95% CI –0.17, 0.39) P=0.43. Heterogeneity in the study designs was a major limitation, hence only a small number (n=6) of studies could be included in the meta-analyses. Meta-analysis failed to show a significant effect of zinc supplementation on cognitive functioning in children though, taken as a whole, there were some small indicators of improvement on aspects of executive function and motor development following supplementation but high-quality RCTs are necessary to investigate this further
Scaling properties of protein family phylogenies
One of the classical questions in evolutionary biology is how evolutionary
processes are coupled at the gene and species level. With this motivation, we
compare the topological properties (mainly the depth scaling, as a
characterization of balance) of a large set of protein phylogenies with a set
of species phylogenies. The comparative analysis shows that both sets of
phylogenies share remarkably similar scaling behavior, suggesting the
universality of branching rules and of the evolutionary processes that drive
biological diversification from gene to species level. In order to explain such
generality, we propose a simple model which allows us to estimate the
proportion of evolvability/robustness needed to approximate the scaling
behavior observed in the phylogenies, highlighting the relevance of the
robustness of a biological system (species or protein) in the scaling
properties of the phylogenetic trees. Thus, the rules that govern the
incapability of a biological system to diversify are equally relevant both at
the gene and at the species level.Comment: Replaced with final published versio
An examination of intentions of recommending fitness centers by user members
The goal of this study was to examine what experiences members have with fitness centers that influence
their intentions for recommendation. After item generation and content validity, as well as a pilot test, a survey was
conducted among members of five different clubs (n=1750). The questionnaire included measures of service quality
attributes, accessibility, well-being in life, well-being in a club, and intentions to recommend a fitness center. Results
using a structural equation model provide evidence that only service quality attributes and well-being in a club have
positive effect on intentions of users to recommend it. Well-being in life has a negative effect on the intentions for recommendation,
while accessibility shows no predictive effect. These findings suggest implications for the management
of a club, such as the need to create a pleasant environment and to provide a personalized service directed towards the
members’ goals in order to improve well-being in a club and contribute to increase the intentions to recommend the
fitness centers to others.O objetivo
deste estudo foi examinar como as experiências de usuários de centros de atividade física interferem nas intenções em
recomendar serviços. Depois de gerar itens e validar o conteúdo, aplicou-se um pré-teste, o questionário final foi aplicado
a sócios de cinco clubes de fitness (n=1.750). O questionário incluiu atributos da qualidade do serviço, acessibilidade,
bem-estar na vida, bem-estar no clube e intenção de recomendar. O modelo de equações estruturais mostrou que apenas
os atributos da qualidade do serviço e bem-estar no clube têm um efeito positivo sobre as intenções de recomendar.
O bem-estar na vida tem um efeito negativo sobre as intenções para recomendar, enquanto que a acessibilidade não
mostra nenhum efeito preditivo. Estas conclusões sugerem a necessidade de criar um ambiente agradável nos clubes e
de oferecer um serviço personalizado para os objetivos dos sócios, a fim de melhorar o bem-estar no clube e contribuir
para a intenção de recomendar o ginásio.
Palavras-chave: intenção de recomendar, atributos da qualSin financiación0.191 SJR (2014) Q3, posición 172/231 Health (social science), 1027/1811 Medicine (miscellaneous); Q4, 112/128 Sports scienceUE
Pathogenic copy number variants and SCN1A mutations in patients with intellectual disability and childhood-onset epilepsy
Background Copy number variants (CNVs) have been linked to neurodevelopmental disorders such as intellectual disability (ID), autism, epilepsy and psychiatric disease. There are few studies of CNVs in patients with both ID and epilepsy. Methods We evaluated the range of rare CNVs found in 80 Welsh patients with ID or developmental delay (DD), and childhood-onset epilepsy. We performed molecular cytogenetic testing by single nucleotide polymorphism array or microarray-based comparative genome hybridisation. Results 8.8 % (7/80) of the patients had at least one rare CNVs that was considered to be pathogenic or likely pathogenic. The CNVs involved known disease genes (EHMT1, MBD5 and SCN1A) and imbalances in genomic regions associated with neurodevelopmental disorders (16p11.2, 16p13.11 and 2q13). Prompted by the observation of two deletions disrupting SCN1A we undertook further testing of this gene in selected patients. This led to the identification of four pathogenic SCN1A mutations in our cohort. Conclusions We identified five rare de novo deletions and confirmed the clinical utility of array analysis in patients with ID/DD and childhood-onset epilepsy. This report adds to our clinical understanding of these rare genomic disorders and highlights SCN1A mutations as a cause of ID and epilepsy, which can easily be overlooked in adults
Dual frequency scatterometer measurement of ocean wave height
A technique for remotely measuring wave height averaged over an area of the sea surface was developed and verified with a series of aircraft flight experiments. The measurement concept involves the cross correlation of the amplitude fluctuations of two monochromatic reflected signals with variable frequency separation. The signal reflected by the randomly distributed specular points on the surface is observed in the backscatter direction at nadir incidence angle. The measured correlation coefficient is equal to the square of the magnitude of the characteristic function of the specular point height from which RMS wave height can be determined. The flight scatterometer operates at 13.9 GHz and 13.9 - delta f GHz with a maximum delta f of 40 MHz. Measurements were conducted for low and moderate sea states at altitudes of 2, 5, and 10 thousand feet. The experimental results agree with the predicted decorrelation with frequency separation and with off-nadir incidence angle
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