Heat transport through quantum Hall edge states: Tunneling versus capacitive coupling to reservoirs

We study the heat transport along an edge state of a two-dimensional electron gas in the quantum Hall regime, in contact to two reservoirs at different temperatures. We consider two exactly solvable models for the edge state coupled to the reservoirs. The first one corresponds to filling $\nu=1$ and tunneling coupling to the reservoirs. The second one corresponds to integer or fractional filling of the sequence $\nu=1/m$ (with $m$ odd), and capacitive coupling to the reservoirs. In both cases we solve the problem by means of non-equilibrium Green function formalism. We show that heat propagates chirally along the edge in the two setups. We identify two temperature regimes, defined by $\Delta$, the mean level spacing of the edge. At low temperatures, $T< \Delta$, finite size effects play an important role in heat transport, for both types of contacts. The nature of the contacts manifest themselves in different power laws for the thermal conductance as a function of the temperature. For capacitive couplings a highly non-universal behavior takes place, through a prefactor that depends on the length of the edge as well as on the coupling strengths and the filling fraction. For larger temperatures, $T>\Delta$, finite-size effects become irrelevant, but the heat transport strongly depends on the strength of the edge-reservoir interactions, in both cases. The thermal conductance for tunneling coupling grows linearly with $T$, whereas for the capacitive case it saturates to a value that depends on the coupling strengths and the filling factors of the edge and the contacts.Comment: 15 pages, 5 figure

Elastic precession of electronic spin states in interacting integer quantum Hall edge channels

We consider the effect of Coulomb interactions in the propagation of electrons, prepared in arbitrary spin states, on chiral edge channels in the integer quantum Hall regime. Electrons are injected and detected at the same energy at different locations of the Hall bar, which is modeled as a chiral Tomonaga-Luttinger liquid. The current is computed perturbatively in the tunneling amplitudes, within a non-crossing approximation using exact solutions of the interacting Green's functions. In the case of different channel velocities, the spin precession effect is evaluated, and the role of interaction parameters and wavevectors is discussed.Comment: 5 pages, 3 figure

Wet oxidation of GeSi at (700)C

About 500-nm-thick films of Ge0.36Si0.64 and Ge0.28Si0.72 grown epitaxially on (100)Si have been oxidized at 700-degrees-C in wet ambient. A uniform GexSi1-xO2 oxide layer forms with a smooth interface between it and the unoxidized GexSi1-x layer below. The composition and structure of that layer remains unchanged as monitored by backscattering spectrometry or cross-sectional transmission electronic microscopy. The oxide of both samples grows as square root of oxidation duration. The parabolic rate constant increases with the Ge content and is larger than that for wet oxidation of pure Si at the same temperature. The absence of a regime of linear growth at this relatively low temperature indicates a much enhanced linear rate constant

Efeitos do treinamento da musculatura do assoalho pélvico sobre o parto e recém-nascido: estudo controlado randomizado

BACKGROUND: The use of the pelvic floor muscle training for urinary incontinence treatment is well established but little is known about its effects in labor and newborn outcomes. OBJECTIVES: To evaluate the effects of antenatal pelvic floor muscle training and strength in labor and newborn outcomes in low-income pregnant women. METHODS: This is a randomized controlled trial that recruited forty-two nulliparous healthy pregnant women aged between 18-36 years old and able to contract the pelvic floor muscles. The participants were included in the study with 20 weeks of gestational age and had their pelvic floor muscles measured by vaginal squeeze pressure. They were randomly allocated into two groups: training group and a non-intervention control group. Then, all participants had their labor and newborn outcomes evaluated through consultation of medical records by a blinded researcher. RESULTS: There were no statistically significant differences between the groups regarding gestational age at birth, type of labor, duration of the second stage of labor, total time of labor, prevalence of laceration, weight and size of the baby, and Apgar score. No correlation was observed between pelvic floor muscle strength and the second stage or the total length of labor. CONCLUSIONS: This randomized controlled trial did not find any effect of pelvic floor muscle training or pelvic floor muscle strength on labor and newborn outcomes.CONTEXTUALIZAÇÃO: O treinamento da musculatura do assoalho pélvico para tratamento da incontinência urinária é bem estabelecida, mas pouco se sabe sobre seus efeitos sobre o parto e o recém-nascido. OBJETIVOS: Avaliar se os desfechos do parto e os resultados dos recém-nascidos são influenciados pelo treinamento e força da musculatura do assoalho pélvico realizados por gestantes de baixa renda. MÉTODOS: Trata-se de um ensaio clínico randomizado que incluiu 42 gestantes nulíparas de baixo risco, com idade entre 18 e 36 anos, e que eram capazes de contrair a musculatura do assoalho pélvico. As gestantes foram incluídas no estudo com 20 semanas de idade gestacional, e realizava-se a avaliação da pressão de contração vaginal pela contração da musculatura do assoalho pélvico. Elas foram randomizadas em dois grupos: grupo de treinamento e grupo controle. Todas as voluntárias tiveram o trabalho de parto e os resultados dos recém-nascidos avaliados por meio de consulta ao prontuário por um pesquisador não envolvido com o grupo de treinamento. RESULTADOS: Não houve diferença significativa entre os grupos quanto à idade gestacional no nascimento, tipo de parto, duração da segunda fase de trabalho de parto, tempo total de trabalho de parto, prevalência da laceração perineal, peso e tamanho do bebê e índice de Apgar. Nenhuma correlação foi encontrada entre a força muscular do assoalho pélvico e a segunda fase ou a duração total do trabalho de parto. CONCLUSÕES: Este ensaio clínico randomizado não verificou qualquer influência do treinamento muscular do assoalho pélvico e da força dos músculos do assoalho pélvico sobre o trabalho de parto e os resultados do recém-nascido

Exposing the human nude phenotype [4]

Peer reviewedSubmitted Versio

Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.

The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by the altitude and position of the area relative to the sun

Ebola Scare and Measles Resurgence: Mandatory Isolation/quarantine and Vaccination

Public outcry for radical isolation and quarantine policies followed the first Ebola diagnosis in the United States when Eric Duncan, upon his return home Oct 2014 from West Africa, then in the midst of a catastrophic Ebola epidemic, tested positive for Ebola. Likewise, the Dec 2014 Disneyland measles outbreak unleashed an angry backlash against parents who refused to have their children vaccinated; and there was public momentum to repeal all legal exemptions to mandatory vaccination of school children. This paper presents an ethical and legal analysis to adjudicate the issue which is at stake in both controversies; namely the inherent conflict between individual rights v. public health when the nation is threatened by serious communicable disease. It presents reasoned arguments, weighing duty-based v. consequence-maximizing ethical principles of right action through application of the felicity calculus (net utility). And the paper demonstrates how the metaethical theory of emotivism is operative in formation and expression of public sentiment which fueled the ethical and legal deliberations

Bipolar disorder and age-related functional impairment

OBJECTIVE: Although bipolar disorder is a major contributor to functional impairment worldwide, an independent impact of bipolar disorder and ageing on functioning has yet to be demonstrated. The objective of the present study was to evaluate the effect of bipolar disorder on age-related functional status using matched controls as a standard. METHOD: One-hundred patients with bipolar disorder and matched controls were evaluated for disability. Age-related effects controlled for confounders were cross-sectionally evaluated. RESULTS: Patients were significantly more impaired than controls. Regression showed effects for aging in both groups. The effect, size, however, was significantly stronger in patients. CONCLUSION: Bipolar disorder was an important effect modifier of the age impact on functioning. While a longitudinal design is needed to effectively demonstrate this different impact, this study further depicts bipolar disorder as a chronic and progressively impairing illness