The global non-entropic arrow of time: from global geometrical asymmetry to local energy flow

Since the nineteenth century, the problem of the arrow of time has been traditionally analyzed in terms of entropy by relating the direction past-to-future to the gradient of the entropy function of the universe. In this paper, we reject this traditional perspective and argue for a global and non-entropic approach to the problem, according to which the arrow of time can be defined in terms of the geometrical properties of spacetime. In particular, we show how the global non-entropic arrow can be transferred to the local level, where it takes the form of a non-spacelike local energy flow that provides the criterion for breaking the symmetry resulting from time-reversal invariant local laws.     

Huntington disease: A case study describing the complexities and nuances of predictive testing of monozygotic twins

When a candidate for predictive testing for the Huntington disease gene is a monozygotic twin, confidentiality of the co-twin's diagnosis and autonomy of participation are among the critical genetic counseling issues. Predictive testing can proceed when twins voluntarily and simultaneously request counseling and evaluation in an HD testing program. This case describes a young man referred for predictive testing to an HD testing site on the East Coast of the United States. Family history revealed a twin brother of unknown zygosity who resided on the West Coast of the United States. The genetic counselors on opposite coasts collaborated to provide genetic counseling and evaluation for voluntary, informed predictive testing of the twins, protecting their rights while observing national protocol guidelines.     

Attainment of an exceptionally high strength in low-carbon steel along with modest ductility through a novel heat treatment route

ABSTRACT

Over the last few decades, the use of steel (the most significant structural engineering material) is facing a significant challenge due to its replacement by other materials (such as composites) possessing higher strength-to-weight ratio/specific strength. This necessitates further enhancement in the strength of steel. In particular, low-carbon steel, in the annealed condition, suffers from inherent problems of poor strength and discontinuous yielding. In this research work a novel heat treatment route of incomplete austenitisation-based cyclic ice-brine quenching has been adopted on low-carbon steel (AISI 1010 steel containing 0.1 wt.% C) without considering any costly alloying or thermo-mechanical treatment. Accordingly, exceptionally high strength (UTS?=?1.7?GPa) and specific strength (226?MPa?g^?1cm³) are achieved after three cycles along with a modest ductility (% Elongation?=?9). This is the highest strength reported so far for low-carbon steel containing 0.1 wt.% C. Yield point phenomenon is also eliminated. This is attributed to a novel microstructure consisting of highly sub-structured fine plate martensite crystals containing internal twin and dislocation tangles along with dispersion of nano-sized cementite particles and clusters of cementite particles.     

瑞典的双生子与子代研究： 通过双生子及其家庭来增加对遗传与环境互动的了解

双生子及子代研究（TOSS）收集了909对双生子及他（她）们的配偶和他（她）们的青少年子女的数据。设计该项目是为研究以下三个问题：1）遗传与环境是如何影响双生子父母的养育方式的？2）遗传与环境是如何影响成年人的家庭关系的？3）家庭关系是如何影响成年人的心理调适的？由于此研究包括了双生子及其子女,该设计可以与其他研究相比较来具体地分析遗传与环境的关联。此研究的结果有助于厘清遗传与环境在养育方式和家庭关系中的型态,同时也澄清了父母亲个人特征是如何影响他（她）们的养育方式,以及父母的个体特征是如何帮助解释了遗传对家庭关系的影响。此研究今后将进一步分析遗传与环境的关联与互动,以及候选基因与环境的关联与互动     

Exploring the Association Between Anxiety and Conduct Problems in a Large Sample of Twins Aged 2–4

Anxiety and conduct problems covary, yet studies have not explored the genetic and environmental origins of this association. We analyzed parent-reported anxiety and conduct problems in 6,783 pairs of twins at 2-, 3-, and 4-years of age. As anxiety and conduct problems were fairly stable across the three ages (average 1-year correlation was .53), ratings from all three were combined. The aggregate anxiety and conduct ratings correlated .33 for boys and .30 for girls. Bivariate genetic analyses indicated fairly low genetic correlations (.31 for boys, .16 for girls), and high shared environmental correlations (1.0 for boys and 0.99 for girls) between anxiety and conduct problems. Most of the phenotypic correlation was accounted for by shared environmental mediation (65% for boys and 94% for girls), indicating that many of the same family environmental factors are responsible for the development of both anxiety and conduct problems.     

Genetics, Dementia, and the Elderly

ABSTRACT— Whether or not an individual develops dementia is powerfully influenced by genes. For Alzheimer's disease, the most common type of dementia, one susceptibility gene with major effects has been identified, but progress finding other susceptibility genes has stalled. Twin studies have revealed that nongenetic risk also plays an important role, as there are many monozygotic twin pairs in which only one individual has dementia. Scientists have argued that gene-by-environment interactions will be key to understanding vulnerability to Alzheimer's disease; but to date, few substantial gene-by-environment interactions have been replicated. Often, too, the nongenetic or lifestyle factor appears to have a protective effect only for those individuals not carrying the risky version of the gene, not for those individuals who are at genetic risk.     

神经心理学手段及其在行为遗传学研究中的应用

神经心理学的检测手段包括神经心理学测验和仪器检查。行为遗传学是一门在多学科基础上发展形成的的交叉学科。近年来,应用神经心理学手段进行行为遗传学研究,已经取得了一些可喜的进展。     

What does a general factor of personality look like in unshared environmental variance?

A general factor of personality (GFP) was obtained solely from unshared environment, by deriving it from the intercorrelations of monozygotic twin differences. This GFP was compared with a GFP derived from correlations reflecting all three components of variance—genes, shared environment, and unshared environment. In two large samples of adult Australian twins, for the items of two questionnaires, the two approaches gave virtually identical GFPs. However, in a sample of adolescent Australian twins, the two GFPs were correlated but distinct.     

The Etiology of Behavior Problems in 7-Year-Old Twins: Substantial Genetic Influence and Negligible Shared Environmental Influence for Parent Ratings and Ratings by Same and Different Teachers

Parent ratings of behavior problems in childhood show substantial genetic influence and modest shared environmental influence. However, few studies have compared these results to teacher ratings and no previous studies have compared same-teacher ratings to different-teacher ratings. 3,714 7-year-old twin pairs in the Twins Early Development Study were rated by parents and teachers on the Strengths and Difficulties Questionnaire. Substantial heritability and negligible shared environmental influence were found for data from all three raters for total behavior problems, hyperactivity, prosocial behavior, peer problems, conduct problems, and emotional symptoms. Sex-limitation models revealed similar results for males and females, although there was some evidence for greater heritability for boys, especially when twins were rated by the same teacher.     

Using Genetic Analyses to Clarify the Distinction Between Depressive and Anxious Symptoms in Children

Self-report measures of depression and anxiety in children are highly correlated and distinguishing between shared and independent factors in their etiologies is therefore problematic. The aim of this article was to test whether less correlated measures of depression and anxiety could be produced and, if so, what genetic and environmental factors would account for the variance in these symptoms. Second-order factor analysis of the items from two standardized self-report questionnaires of depression and anxiety collected from 395 pairs of same-sex twins aged 8 to 16 years resulted in purer dimensions of depression and anxiety. Behavioral genetic analyses confirmed the distinction between these two dimensions, and bivariate analyses revealed that the association between the two was primarily accounted for by shared genetic factors.