Semiconductor quantum dots devices: Recent advances and application prospects

In this paper, a brief review will be given on recent advances in semiconductor quantum dots based optoelectronic devices. The focus will be on two major application areas, i.e., telecom devices and high power light sources, where some device examples will be discussed on the current status and for the future prospect

Weak antilocalization in quasi-two-dimensional electronic states of epitaxial LuSb thin films

Observation of large non-saturating magnetoresistance in rare-earth monopnictides has raised enormous interest in understanding the role of its electronic structure. Here, by a combination of molecular-beam epitaxy, low-temperature transport, angle-resolved photoemssion spectroscopy, and hybrid density functional theory we have unveiled the bandstructure of LuSb, where electron-hole compensation is identified as a mechanism responsible for large magnetoresistance in this topologically trivial compound. In contrast to bulk single crystal analogues, quasi-two-dimensional behavior is observed in our thin films for both electron and holelike carriers, indicative of dimensional confinement of the electronic states. Introduction of defects through growth parameter tuning results in the appearance of quantum interference effects at low temperatures, which has allowed us to identify the dominant inelastic scattering processes and elucidate the role of spin-orbit coupling. Our findings open up new possibilities of band structure engineering and control of transport properties in rare-earth monopnictides via epitaxial synthesis.Comment: 20 pages, 12 figures; includes supplementary informatio

Variation and Optimality

This study procedes from two fundamental assumptions which have nevertheless not always received wide acceptance in the fields of phonology and sociolinguistics: (1) that variable or optional rules, and the empirical, quantitative study of variation in language, may have important implications for theories of phonological/morphological derivation

Grounded Duoethnography: A Dialogic Method for the Exploration of Intuition Through Divergence and Convergence

Ausgehend von unserer jeweiligen Intuition zu unserem Bedürfnis, einen Ort als "Heimat" zu benennen, haben wir eine methodologische Bricolage zur Untersuchung dieses Konzepts versucht. Wir griffen dabei auf die konstruktivistische Grounded-Theory-Methodologie (CHARMAZ 2006; CHARMAZ & KELLER 2016) und auf die Duoethnographie (NORRIS & SAWYER 2012) zurück, die wir in einer Grounded Duoethnografie verbanden. Obwohl wir diesen Ansatz dezidiert in einem konstruktivistischen Paradigma verorten, nutzten wir zugleich  postmoderne und poststrukturalistische Überlegungen insbesondere angelehnt an CLARKEs (2009, 2019) Situationsanalyse und die Umsetzung des Bachtinschen Dialogs bei NORRIS und SAWYER (2012), um im Verlauf der Exploration von Konvergenzen und Divergenzen unserer Erfahrungen und Expertisen ein gemeinsames Narrativ zu generieren. Auf diese Weise haben wir zentrale mit "Heimat" verbundene Konzepte identifizieren können. Im Beitrag skizzieren wir den methodologischen Hintergrund und die Anwendung der Grounded Duoethnografie und zeigen an einem Beispiel, wie dieser Ansatz uns als Wissenschaftlerinnen sensibilisiert hat.Motivated by our respective intuition about our need for a place called "home," we engaged in methodological bricolage to study the concept. We draw upon methodological traditions of constructivist grounded theory methodology (CHARMAZ, 2006; CHARMAZ & KELLER, 2016) and duoethnography (NORRIS & SAWYER, 2012) to envision and conduct a grounded duoethnography. Ultimately positioning the methodology within a constructivist paradigm, we nevertheless draw upon the complexities of postmodernism and poststructuralism, specifically as invoked in CLARKE's (2009, 2019) situational analysis and NORRIS and SAWYER's (2012) application of Bakhtinian dialogue to create a shared narrative through the exploration of the convergences and divergences of our experiences and expertise. Through these dialogues we identify core concepts related to "home." We elaborate on the background and application of this methodology and briefly describe an example to demonstrate how these concepts have sensitized us as scholars

Lesbian, Gay, and Bisexual Students Experiencing Homelessness and Substance Use in the School Context: A Statewide Study

PURPOSE This study explored differences between lesbian, gay, and bisexual (LGB)-housed and homeless students regarding substance use patterns on and off school grounds and the unique contribution of homelessness to substance use in school. METHODS Data were from the 2013-2015 California Healthy Kids Survey, a statewide survey of school protective factors and risk behaviors. A representative sample of 9th- and 11th-grade students (N = 20,337) was used. Comparisons between housed (n = 19,456) and homeless (doubled up: n = 715; acute homeless: n = 166) LGB students were conducted. We used chi-square tests to compare rates of lifetime, past-30-day, and in-school substance use and conducted multivariate logistic regression models for each substance use variables. RESULTS Chi-square test results indicated significant differences in rates of substance use among students experiencing homelessness (both categories) and housed LGB students. Lesbian, gay, and bisexual students experiencing homelessness were more likely to report substance use off and on school grounds. Results from logistic regression analyses indicated that LGB students who experience homelessness were significantly more likely to report recent and in-school substance use. For example, students experiencing acute homelessness were about 3 times as likely to report heavy episodic drinking (adjusted odds ratio [AOR] = 3.13; 95% confidence interval [CI] = 2.13, 4.26) and more than 5 times as likely to smoke marijuana in school (AOR = 5.38; 95% CI = 3.46, 8.36), compared to housed LGB students. CONCLUSIONS LGB students who experience homelessness are at higher risk than housed LGB students of substance use on and off school grounds. Findings highlight the need to provide support in the school context for this subpopulation

Shattered Vision: Disenchantment of Couplehood Among Female Survivors of Violence in the Shadow of their Family-of-Origin Experiences

Abstract This article describes and analyzes the relationship disenchantment of couplehood among female survivors of violence and their family-of-origin experiences of abuse. Twenty Israeli women who were survivors of violence participated in this qualitative research. Each woman underwent three indepth interviews, two for data collection and one for validating the themes emerging from content analysis. Data analysis revealed that female survivors of violence aim to overcome the distress and pain of emotional and physical violence experienced in their family of origin, by constructing a couplehood vision imbued with a feeling of power, meaning, hope, and freedom. Partner violence shattered the women's vision of couplehood, leading to crisis, disillusionment, and disenchantment in their marital relationships

Applying Private Information Retrieval to Lightweight Bitcoin Clients

Lightweight Bitcoin clients execute a Simple Payment Verification (SPV) protocol to verify the validity of transactions related to a particular user. Currently, lightweight clients use Bloom filters to significantly reduce the amount of bandwidth required to validate a particular transaction. This is despite the fact that research has shown that Bloom filters are insufficient at preserving the privacy of clients' queries. In this paper we describe our design of an SPV protocol that leverages Private Information Retrieval (PIR) to create fully private and performant queries. We show that our protocol has a low bandwidth and latency cost; properties that make our protocol a viable alternative for lightweight Bitcoin clients and other cryptocurrencies with a similar SPV model. In contract to Bloom filters, our PIR-based approach offers deterministic privacy to the user. Among our results, we show that in the worst case, clients who would like to verify 100 transactions occurring in the past week incurs a bandwidth cost of 33.54 MB with an associated latency of approximately 4.8 minutes, when using our protocol. The same query executed using the Bloom-filter-based SPV protocol incurs a bandwidth cost of 12.85 MB; this is a modest overhead considering the privacy guarantees it provides

Screen use and health habits of youth

Purpose: Adulthood health habits among individuals develop in our youth. What are the influences that create our health habits such as eating healthy foods, engaging in exercise and not smoking? In our complicated society, Uri Bronfenbrenner\u27s Bioecological theory suggests a systematic approach at examining the layers of influence that surround us and shape our behaviors. The theory views the child as encased by a concentric series of layers, each layer having an impact on the next and all layers exude direct or indirect influences on the child at the center. At the center are the unique characteristics and traits of the child, which in turn are reflected by the child\u27s behaviors. The first layer of influence, closest to the child at the center, has the most influence on the child. Distal to the parents\u27 layer of influence is the layer of peer influences, which may include social and online networks. More distal to those layers of influence are those from teachers, and the community. The more proximal these influences are to the child at the center, the more likely they are to affect the child. Proximity of these influences also depends on exposure. That is, some youth may watch television or engage in social networking at a much higher frequency than other youth; consequently, their influences may be higher on youth\u27s behavior. Already some studies found that certain types of screen use (i.e., television, 3rd generation telephones, the internet) are associated with health status. It may be that youth choose to engage in screen use rather than engage in physical activity. Or perhaps, screen use is a refuge for those with poor self-esteem. This latter hypothesis has received considerable attention. This study sought to build on the existing information by (1) examining sources of health information among youth (i.e., parents, screen use, others), (2) measuring the association between hours of screen use and health habits, and (3) determining whether self-esteem confounds or interacts with the relationship between screen use and healthy habits. Methods: This cross-sectional study consists of a paper-and-pencil survey and will be administered to a large sample of youth, ages 15-18 (n=600). Currently, this study is in the process of data collection. Preliminary data were used to examine the relationship between sources of health information, existing health habits and self-esteem. Results: Youth have many sources of health information including parents, teachers and friends, as well as screens such as television, 3rd generation telephones and the internet. The vast majority of youth have access to the internet, television or cell phones (98%); but the amount of screen use varies between 1-19 hours per day (mean=5.41, SD=4.39). Hours of screen use are significantly related to health habits (p\u3c0.001); however, self-esteem appears largely unrelated to health habits for both boys and girls. Conclusions: Youth use health information from many sources available to them. Although these preliminary data support previous studies\u27 findings that longer hours of screen use are associated with poorer health habits, there was no evidence to support the belief that self-esteem influenced the relationship between screen use and health habits. Health professionals interested in designing materials to influence youth will need to disseminate information to parents, teachers and through the internet, as youth glean information from all these sources. Moreover, the importance of youth self-esteem must be in the forefront of efforts to promote healthy habits