Polynomial extensions of semistar operations

We provide a complete solution to the problem of extending arbitrary semistar operations of an integral domain $D$ to semistar operations of the polynomial ring $D[X]$. As an application, we show that one can reobtain the main results of some previous papers concerning the problem in the special cases of stable semistar operations of finite type or semistar operations defined by families of overrings. Finally, we investigate the behavior of the polynomial extensions of the most important and classical operations such as $d_D$, $v_D$, $t_D$, $w_D$ and $b_D$ operations

Compreensão leitora nos últimos anos dos ciclos I e II do Ensino Fundamental

PURPOSE:To characterize students' performance in Cycle I and II of the Elementary School (EF), in decoding, reading comprehension and underlying skills of reading, and investigate correlations between these variables, in the absence and presence of reading comprehension deficits, identified by their teachers.METHODS:125 students from ES were grouped according to Cycle and presence or absence of reading comprehension impairments. Two Control (good readers from both Cycles) and two Research groups (poor readers from both Cycles) were established. Assessment involved: fluency and reading comprehension; oral comprehension; working and short-term phonological memory; grammar closure. It was compared (Mann-Whitney test): in intragroup study, both Control and Research groups; in intergroup study, Control and Research from different cycles, and Control I and Research II. Spearman coefficient investigated correlations.RESULTS:Analyzing reading comprehension, we observed better performance of Control Groups in all tasks in comparison to the respective Research Groups, and better performance of Control II in comparison to Control I. Research Groups had similar results in most tests. Positive correlations have been observed between most of the variables.CONCLUSION:Students without reading comprehension impairments showed better performance in reading in both Cycles. Working memory and oral comprehension did not differentiate students with and without complaints in Cycle I, differently from what was observed in Cycle II. Research II presented similar or better performance than Research I and similar or worse performance than Control I. Underlying skills showed different profiles of correlation with reading comprehension capacity, according to the group.OBJETIVO:Caracterizar o desempenho de escolares do Ciclo I e II do Ensino Fundamental (EF), em decodificação, compreensão leitora e habilidades subjacentes à leitura, e investigar correlações entre essas variáveis, na ausência e na presença de prejuízos da compreensão leitora, identificados pelos professores.MÉTODOS:Participaram 125 escolares do EF, agrupados segundo o Ciclo e a presença ou ausência de indicativos de prejuízos de compreensão leitora. Estabeleceram-se dois Grupos Controle (bons compreendedores de ambos os Ciclos) e dois Grupos Pesquisa (pobres compreendedores de ambos os Ciclos). Avaliaram-se: fluência e compreensão leitora; compreensão oral; memória fonológica de curto prazo e operacional; closura gramatical. Comparou-se (Teste de Mann-Whitney): em estudo intragrupo, os dois Grupos Controle e os dois Grupos Pesquisa; em estudo intergrupo, Controle e Pesquisa dos diferentes ciclos e Controle I e Pesquisa II. O coeficiente de Spearman investigou correlações entre as variáveis.RESULTADOS:Quanto à compreensão leitora, observou-se: melhor desempenho dos Controle em todas as tarefas, comparados aos respectivos Pesquisa; melhor desempenho do Controle II comparado ao Controle I. Os Pesquisa foram semelhantes na maioria das provas. Observaram-se correlações positivas entre a maioria das variáveis estudadas.CONCLUSÃO:Os Controle mostraram melhor desempenho em leitura, nos dois ciclos. Memória de trabalho e compreensão oral não diferenciaram escolares no Ciclo I, ao contrário do observado no Ciclo II. O Pesquisa II foi semelhante ou melhor que o Pesquisa I e semelhante ou pior que o Controle I. Habilidades subjacentes mostraram diferentes perfis de correlação com a capacidade de compreensão leitora, segundo o grupo.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Department of Speech-Language Pathology and AudiologyUNIFESP, EPM, Department of Speech-Language Pathology and AudiologySciEL

Aharonov-Bohm-Coulomb Problem in Graphene Ring

We study the Aharonov-Bohm-Coulomb problem in a graphene ring. We investigate, in particular, the effects of a Coulomb type potential of the form $\xi/r$ on the energy spectrum of Dirac electrons in the graphene ring in two different ways: one for the scalar coupling and the other for the vector coupling. It is found that, since the potential in the scalar coupling breaks the time-reversal symmetry between the two valleys as well as the effective time-reversal symmetry in a single valley, the energy spectrum of one valley is separated from that of the other valley, demonstrating a valley polarization. In the vector coupling, however, the potential does not break either of the two symmetries and its effect appears only as an additive constant to the spectrum of Aharonov-Bohm potential. The corresponding persistent currents, the observable quantities of the symmetry-breaking energy spectra, are shown to be asymmetric about zero magnetic flux in the scalar coupling, while symmetric in the vector coupling.Comment: 20 pages, 12 figures (V2) 18 pages, accepted in JPHYS

The Korean urban rural elderly cohort study: study design and protocol

BACKGROUND: Korea is one of the fastest aging countries and is expected to become a super-aged society within 12 years. The Korean Urban Rural Elderly (KURE) study was developed to evaluate the epidemiological characteristics and establish the prevention and management of major disorders of the elderly in Korea. METHODS/DESIGN: The KURE study is a community-based prospective cohort study on health, aging, and common geriatric disorders of Korean elderly persons aged at least 65 years. To construct a cohort reflecting both urban and rural areas, we selected 2 representative communities in the country. To establish multidisciplinary approaches to geriatric health, this study was performed by researchers in the divisions of geriatrics, preventive medicine, endocrinology, and sociology. The baseline examinations began in 2012; the study will follow more than 4,000 elderly Koreans over 10 years. The first and second follow-up health examinations will be performed every 4 years. Every 2 years after each health examination, inter-assessment interview will be conducted to improve participant retention. DISCUSSION: The KURE study will provide longitudinal epidemiologic data on health, aging, and common geriatric disorders of the elderly in Korea. This is a comprehensive, multidisciplinary study of the elderly with respect to biological, physical, socio-economic, and environmental factors. The results of this study will contribute to improve public health and welfare policies for the aging society in Korea

Potassium chloride elicits enhancement of bilobalide and Ginkgolides production by Ginkgo biloba cell cultures

This study investigated the ability of potassium chloride (KCl) to elicit the production of bilobalide (BB), ginkgolide A (GA) and ginkgolide B (GB) by Ginkgo biloba cell suspension cultures. The salt stress by KCl treatments increased production of BB, GA and GB in both suspended cells and cultured medium. Especially, treatment of KCl 800 mM of highest concentration was stimulated emission into cultured medium BB, GA and GB compounds accumulated in cells. Although KCl 800 mM severely inhibited cells growth, the maximum content of GA and GB in cells was obtained in the treatment of KCl 800 mM, which was 1.9 and 4.0 times higher than the control. These results thus suggest that salt stress can afford enhanced production of secondary metabolites by plant cell cultures