Competitive Processes in Cross‐Situational Word Learning

Cross‐situational word learning, like any statistical learning problem, involves tracking the regularities in the environment. However, the information that learners pick up from these regularities is dependent on their learning mechanism. This article investigates the role of one type of mechanism in statistical word learning: competition. Competitive mechanisms would allow learners to find the signal in noisy input and would help to explain the speed with which learners succeed in statistical learning tasks. Because cross‐situational word learning provides information at multiple scales—both within and across trials/situations—learners could implement competition at either or both of these scales. A series of four experiments demonstrate that cross‐situational learning involves competition at both levels of scale, and that these mechanisms interact to support rapid learning. The impact of both of these mechanisms is considered from the perspective of a process‐level understanding of cross‐situational learning.     

不同线索下特质焦虑个体的返回抑制

焦虑与注意偏向的研究是近年来情绪与认知领域的热点。为探讨特质焦虑个体的注意偏向特点及其返回抑制能力是否受不同线索的调节, 采用特质焦虑量表筛选高特质焦虑大学生29名, 低特质焦虑大学生28名完成线索-靶子任务。要求被试在提示线索消失后, 对位置进行快而准地辨别反应, 分别探索中性和情绪性提示线索下被试的返回抑制。结果发现：(1)在中性线索条件下, 高焦虑个体平均反应时慢于低焦虑个体。(2) 在情绪线索条件下, 高焦虑个体在负性线索下的反应时小于在正性线索下的反应时; 高、低焦虑个体在各种SOA条件下均出现了返回抑制, 但各组返回抑制量受到情绪线索的调节：在正性情绪线索条件下, 两组返回抑制量没有显著差异; 在负性情绪线索下, 高焦虑个体返回抑制量显著小于低焦虑个体。这表明, (1)焦虑个体的注意偏向受到刺激信息的影响：只对负性情绪线索出现注意警觉; (2)只有在涉及负性情绪信息时高、低焦虑个体返回抑制能力才有差异, 高焦虑个体存在对负性情绪线索的抑制困难。     

Long-term natural ageing of a dissociated dislocation in a Cu-13.43 at.% Al alloy

The nature of impurity-dislocation interactions is one of the key questions governing the strength and plasticity of solid-solution materials. To investigate the influence of impurities on the mechanical properties of intermetallic NiAl, the electronic structure and energy of NiAl with a <100>{010} edge dislocation and transition-metal impurities was calculated using the real-space tight-binding linear muffin-tin orbital method. The localized electronic states, appearing in the core of the dislocation, are found to lead to strong impurity-dislocation interactions via two mechanisms: firstly, chemical locking, due to strong hybridization between impurity electronic states and dislocation localized states; secondly, electrostatic locking, due to long-range charge oscillations caused by the electron localization in the dislocation core. The results obtained explain qualitatively why the solid-solution hardening effect in NiAl correlates with the electronic structure of impurities rather than with size misfit, as expected according to traditional views.     

Real temperature of nanoparticles in electron microscope beams

Abstract

This Letter presents a solution of the problem of the real temperature of nanoparticles under conditions of electron microscope beam irradiation. It is shown that the average temperature of the nanoparticles (NPs) may increase to several hundred degrees depending on contact conditions with the substrate, the intensity of the beam and the size of the NPs. The temperature increases with NP size a according to the dependence: T α a² for sufficiently small particles.     

The kinetics of infralow-frequency viscoelastic internal friction induced by irreversible structural relaxation of a metallic glass

This letter presents the results of internal-friction measurements of Co 70 Fe 5 Si 15 B10 metallic glass at temperatures 400K h T h 700K and frequencies 0.01 Hz h f h 0.05Hz. It is shown that Maxwellian viscoelastic damping is predominant in this case. The nature of this damping is determined by irreversible structural relaxation. The kinetic relaxation law is derived.     

Role of cross-slipping in formation of edge dislocations in heteroepitaxial systems GeSi-on-Si(001) and Ge-on-InGaAs/GaAs

Edge misfit dislocations (MDs) formed as result of reactions between 60° glissile threading dislocations and 60° MDs lying on an intersecting glide plane were found in strained GeSi-on-Si(001) and Ge-on-InGaAs/GaAs films. It was demonstrated that dislocations penetrating from the InGaAs buffer layer to the strained Ge film can provoke formation of not only 60° MDs, but also edge MDs on the interface even at minor mismatch of the lattice parameters of the film and the InGaAs/GaAs virtual substrate.     

Contributions of Head-Mounted Cameras to Studying the Visual Environments of Infants and Young Children

Head-mounted video cameras (with and without an eye camera to track gaze direction) are being increasingly used to study infants’ and young children's visual environments and provide new and often unexpected insights about the visual world from a child's point of view. The challenge in using head cameras is principally conceptual and concerns the match between what these cameras measure and the research question. Head cameras record the scene in front of faces and thus answer questions about those head-centered scenes. In this “Tools of the Trade” article, we consider the unique contributions provided by head-centered video, the limitations and open questions that remain for head-camera methods, and the practical issues of placing head cameras on infants and analyzing the generated video.     

自尊的遗传性:来自双生子研究的证据

自尊是个体差异的一个重要方面,迄今已有许多研究从行为遗传学角度探讨自尊个体差异的来源。通过梳理现有关于自尊的双生子研究,发现:1)自尊有中等的遗传度,其个体差异来自遗传和非共享环境;2)遗传对自尊的稳定性有较大作用;3)自尊与认知、情感的联系主要源自共同的遗传基础。总之,遗传对自尊具有重要影响。未来双生子研究可拓展到自尊波动性、内隐自尊等领域,并考虑极端人群的遗传特异性和文化对自尊遗传性的影响。     

Uptake of Cardiac Screening and Genetic Testing Among Hypertrophic and Dilated Cardiomyopathy Families

Cardiomyopathy is a genetically and clinically heterogeneous, life threatening disease which affects people of all ages. Recent guidelines provide recommendations for cardiac screening and genetic testing in at-risk relatives, but the uptake and impact of these measures in the United States is unknown. This is a single institution retrospective study that characterizes the uptake of cardiac screening and genetic testing for relatives of a cohort of 57 probands with hypertrophic (HCM) and dilated cardiomyopathy (DCM) who underwent both clinical evaluation and genetic testing. Cardiac screening was indicated for 302 relatives. One hundred and seventy-three (57 %) completed cardiac screening. Forty of the 57 probands were mutation positive and genetic testing was indicated for 213 relatives. Eighty-four (39 %) completed genetic testing. The uptake of cardiac surveillance was greater than the uptake of genetic testing (p?<?0.0001) among relatives of mutation positive probands. Within the group of at-risk, asymptomatic relatives of probands, cardiac screening and genetic testing were positive in 25 % and 40 % of cases, respectively. These data demonstrate the important role and utility of cascade cardiac screening and genetic testing in the care of patients and families with HCM or DCM. The approach to cardiac screening and genetic testing should be family-specific and requires expertise in the genetics of cardiomyopathy.     

Ethical Considerations for Volunteer Recruitment of Visual Prosthesis Trials

With the development of visual prostheses research from the engineering phase to clinical trials, volunteer recruitment for the early visual prosthesis trials needs to be carefully considered. In this article, we mainly discuss several issues related to volunteer recruitment that had posed serious challenges to the visual prosthesis trials, such as low rates of participants, high expectations and underlying motivations to participate in the visual prosthesis trials as well as the importance of informed consent. When recruiting volunteers for visual prosthesis implants, it is critical that the visual prosthesis researchers should not only take into account the patient’s expectations and motivations, but also make the patients fully aware of the possible benefits and risks involved with their participation, and help patients establish realistic expectations for the early phase of visual prosthesis implantation. Based on these considerations to the challenges, eligible volunteers may be recruited in the preliminary stages of visual prosthesis trials.