Edge channel mixing induced by potential steps in an integer quantum Hall system

We investigate the coherent mixing of co-propagating edge channels in a quantum Hall bar produced by step potentials. In the case of two edge channels it is found that, although a single step induces only a few percent mixing, a series of steps could yield 50% mixing. In addition, a strong mixing is found when the potential height of a single step allows a different number of edge channels on the two sides of the step. Charge density probability has been also calculated even for the case where the step is smoothened.Comment: final version: 7 pages, 6 figure

Unpacking the difference between digital transformation and IT-enabled organizational transformation

Although digital transformation offers a number of opportunities for today’s organizations, information systems scholars and practitioners struggle to grasp what digital transformation really is, particularly in terms of how it differs from the well-established concept of information technology (IT)-enabled organizational transformation. By integrating literature from organization science and information systems research with two longitudinal case studies—one on digital transformation, the other on IT-enabled organizational transformation—we develop an empirically grounded conceptualization that sets these two phenomena apart. We find that there are two distinctive differences: (1) digital transformation activities leverage digital technology in (re)defining an organization’s value proposition, while IT-enabled organizational transformation activities leverage digital technology in supporting the value proposition, and (2) digital transformation involves the emergence of a new organizational identity, whereas IT-enabled organizational transformation involves the enhancement of an existing organizational identity. We synthesize these arguments in a process model to distinguish the different types of transformations and propose directions for future research

Echo-endoscopic appearance of mediastinal metastasis from papillary renal carcinoma.

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Epoxy-cross-linked Polyamine CO2 Sorbents Enhanced via Hydrophobic Functionalization

Optimizing sorption capacity and amine efficiency are among the major challenges in developing solid carbon dioxide sorbents. Such materials frequently feature polyamines impregnated onto supports adding weight to the sorbents. This work presents the cross-linking of polyethyleneimine (PEI) by the industrially available epoxy resin, bisphenol-A diglycidyl ether (DER) to form support-free sorbent materials. Prior to cross-linking, the polyamine chain is functionalized with hydrophobic additives; one material modified with the branched chain hydrocarbon 2-ethylhexyl glycidyl ether displays CO2 uptake of 0.195 g/g, 4.43 mmol CO2/g (1 atm single component CO2, 90 °C). The additive loading affects the cross-linking, with the lesser cross-linked materials showing more favorable sorption capacities and higher amine efficiencies. The type of additive also influences sorption, with the larger, longer and bulkier additives better able to free the amine from their hydrogen bonding network, generally promoting better sorption. As well as increasing CO2 uptake, the additives also reduce the optimum sorption temperature, offering a handle to tune sorbents for specific working conditions. The best performing material shows high selectivity for CO2 sorption, and under sorption cycles in a 10% CO2/90% N2 mixture, utilizing temperature swing desorption, demonstrates a good working capacity of 9.5% CO2 uptake over the course of 29 cycles. Furthermore, humidity has been found to promote CO2 sorption at lower temperatures with a CO2 uptake of 0.235 g/g, 5.34 mmol/g (1 atm single component CO2, 25 °C) using a pre-hydrated sample. Overall, these findings confirm the value of our approach where cross-linking emerges as a valid and practical alternative to loading polyamines onto solid supports. This work demonstrates the versatility of these types of materials and their potential for use in large scale carbon capture systems

Annotating ritual in ancient greek tragedy: A bottom-up approach in action

EuporiaRAGT is one of the pilot projects that adopt the Euporia system as a digital support to an historico-anthropological research on the form and function of rituals in the texts of ancient Greek tragedy. This paper describes the bottom-up approach adopted in the project: During the annotation stage, performed with a Domain Specific Language designed with a usercentred approach, the domain expert can annotate ritual and religious phenomena, with the possibility of registering different textual and interpretive variants; the design of a search engine, in a second phase of the work, allows the database to be tested and reorganized. Finally, the construction of an ontology allows to structure the tags, in order to perform complex queries on the database

Semen qualitative parameters and spermatozoon ultrastructure of Phasianus colchicus mongolicus

In many European countries, the common pheasant is one of the most popular game bird species. Despite its popularity, little information has been published related to its sperm profile, including the common semen parameters used to characterise the quality of this material. Additionally, the spermatozoon's ultrastructure has never been characterised, and very few data on reproductive performance in the male bird are available. The aim of the present study was to provide these data and fill these gaps in the literature. Semen was collected by the dorso-abdominal massage technique for pheasants and evaluated during the late spring period (May to mid-June). For the ultrastructure and morphometric descriptions, scanning electron and transmission electron images were obtained. The data show that pheasants produce ejaculates of a smaller volume (average volume = 131 mu L) but with a higher sperm concentration compared with roosters. Semen pH values tended towards alkaline values (average pH = 8.3). The general shape of the pheasant spermatozoon resembles that of roosters and turkeys, although a bigger sub-acrosomal space was observed compared with these species. As a consequence, its perforatorium occupies two-thirds of the acrosome. A lower number of mitochondria (20-24) was also detected compared with roosters and turkeys. The pheasant spermatozoon's dimensions are most similar to those observed in turkeys and guineafowl. The present study provides basic information useful for assisted reproductive techniques and conservation programmes

The predicted relative risk of premature ovarian failure for three radiotherapy modalities in a girl receiving craniospinal irradiation

In girls and young women, irradiation of the ovaries can reduce the number of viable ovarian primordial follicles, which may lead to premature ovarian failure (POF) and subsequently to sterility. One strategy to minimize this late effect is to reduce the radiation dose to the ovaries. A primary means of reducing dose is to choose a radiotherapy technique that avoids irradiating nearby normal tissue; however, the relative risk of POF (RRPOF) due to the various therapeutic options has not been assessed. This study compared the predicted RRPOF after craniospinal proton radiotherapy, conventional photon radiotherapy (CRT) and intensity-modulated photon radiotherapy (IMRT). We calculated the equivalent dose delivered to the ovaries of an 11-year-old girl from therapeutic and stray radiation. We then predicted the percentage of ovarian primordial follicles killed by radiation and used this as a measure of the RRPOF; we also calculated the ratio of the relative risk of POF (RRRPOF) among the three radiotherapies. Proton radiotherapy had a lower RRPOF than either of the other two types. We also tested the sensitivity of the RRRPOF between photon and proton therapies to the anatomic position of the ovaries, i.e., proximity to the treatment field (2 ≤ RRRPOF ≤ 10). We found that CRT and IMRT have higher risks of POF than passive-scattering proton radiotherapy (PRT) does, regardless of uncertainties in the ovarian location. Overall, PRT represents a lower RRPOF over the two other modalities. © 2013 Institute of Physics and Engineering in Medicine

Effectiveness of school-based nutrition education interventions to prevent and reduce excessive weight gain in children and adolescents: a systematic review

OBJETIVO: Avaliar a efetividade da educação nutricional em escolas na redução ou prevenção de sobrepeso e obesidade em crianças e adolescentes. FONTES DOS DADOS: Busca sistemática em 14 bases de dados e cinco revisões sistemáticas por ensaios controlados randomizados realizados em escolas com o objetivo de reduzir ou prevenir o sobrepeso em crianças e adolescentes. O índice de massa corporal e o consumo de frutas e verduras foram utilizados como desfechos primário e secundário, respectivamente. Não houve restrição de data de publicação ou idioma, exceto para idiomas com logogramas. Excluímos estudos em populações com distúrbios alimentares, dislipidemia, diabetes e deficiência física ou mental, e que utilizassem medicamentos ou suplementos alimentares. A avaliação por título e resumo e a avaliação de qualidade foram realizadas de forma independente por dois pesquisadores. Utilizamos as orientações do Centre for Reviews and Dissemination para a elaboração de artigos de revisão em saúde e o programa EPPI-Reviewer 3. SÍNTESE DOS DADOS: Das 4.809 referências inicialmente encontradas, 24 artigos preencheram os critérios de inclusão. Os dados extraídos apresentam evidências de efeitos antropométricos positivos e de aumento no consumo de frutas e verduras. As intervenções com as seguintes características demonstraram ser efetivas: duração > 1 ano, introdução como atividade regular da escola, envolvimento dos pais, introdução da educação nutricional no currículo regular e fornecimento de frutas e verduras pelos serviços de alimentação da escola. CONCLUSÃO: As intervenções para reduzir o sobrepeso e a obesidade e aumentar o consumo de frutas e verduras foram efetivas nos estudos bem conduzidos.OBJECTIVE: To evaluate the effectiveness of school-based nutrition education in reducing or preventing overweight and obesity in children and adolescents. SOURCES: Systematic search in 14 databases and five systematic reviews for randomized controlled trials conducted in schools to reduce or prevent overweight in children and adolescents. Body mass index and fruit and vegetable intake were used as primary and secondary measures of outcome, respectively. There was no restriction by date of publication or language, except for languages with structured logograms. We excluded studies on specific populations presenting eating disorders, dyslipidemia, diabetes, and physical or mental disabilities, as well as studies that used drugs or food supplements as components of the intervention. The assessment by title and abstract and the quality assessment were performed independently by two researchers. We used the Centre for Reviews and Dissemination's guidance for undertaking reviews in health care and the software EPPI-Reviewer 3. SUMMARY OF THE FINDINGS: From the initially retrieved 4,809 references, 24 articles met the inclusion criteria. The extracted data show that there is evidence of positive effects on anthropometry and of increase in fruit and vegetable consumption. Characteristics of the interventions that demonstrated effectiveness are: duration > 1 year, introduction into the regular activities of the school, parental involvement, introduction of nutrition education into the regular curriculum, and provision of fruits and vegetables by school food services. CONCLUSION: Interventions in schools to reduce overweight and obesity, as well as to increase fruits and vegetable consumption, have demonstrated effectiveness in the best-conducted studies