Spinorial Characterizations of Surfaces into 3-dimensional pseudo-Riemannian Space Forms

We give a spinorial characterization of isometrically immersed surfaces of arbitrary signature into 3-dimensional pseudo-Riemannian space forms. For Lorentzian surfaces, this generalizes a recent work of the first author in $\mathbb{R}^{2,1}$ to other Lorentzian space forms. We also characterize immersions of Riemannian surfaces in these spaces. From this we can deduce analogous results for timelike immersions of Lorentzian surfaces in space forms of corresponding signature, as well as for spacelike and timelike immersions of surfaces of signature (0,2), hence achieving a complete spinorial description for this class of pseudo-Riemannian immersions.Comment: 9 page

Wake up economists! - Currency-issuing central governments have no budget constraint

Abstract: Despite what mainstream economists preach, currency-issuing central governments have no budget constraint. It is therefore incumbent upon them to use their unique spending and taxing powers to achieve the broader goal of sustainable development. Their failure to do so has meant that nations have fallen well short of realising their full potential. Rather than accept the neo-liberal myth that ‘small government is best’, the citizens of a nation should welcome the central-government’s responsible use of their unique spending and taxing powers to provide sufficient public goods and critical infrastructure, achieve and maintain full employment, resolve critical social and environmental concerns, and meet the requirements of an aging population. Should central governments fail in their responsibility to prudently use their unique powers, public disapproval is best registered through the ballot box, not through degenerative debates that distort the facts about the operation of a modern, fiat-currency economy.Keywords: Central governments, government budgets, fiscal and monetary policy, sustainable development

Dietary intakes and body composition of Māori and Pacific women in the women's EXPLORE study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand

The most thorough record of dietary intake among New Zealand (NZ) Māori and Pacific women was undertaken in the 2008 NZ Adult Nutrition Survey, but it did not consider the relationship with body composition. The aim of this study was to investigate the relationship between dietary intake and body composition (particularly body mass index (BMI) and body fat (BF) percentage) of all Māori (n=79) and Pacific (n=75) women (16-45 years old) recruited in the women’s EXPLORE study. Anthropometric data was measured using weight, height, and air displacement plethysmography (BodPod), while dietary data was assessed using a validated, 220-item, semi-quantitative food frequency questionnaire. On average, the BMI (28.2 kg/m2) and BF (34.6%) of Māori women classified them as overweight, while the average BMI (31.9 kg/m2) and BF (37.8%) of Pacific women classified them as obese. There were significant positive correlations between the BMI and BF percentage of Māori (r=0.86) and Pacific women (r=0.87), which suggests BMI is a good indicator of BF percentage in these populations. The percentage of Māori and Pacific women who exceeded their estimated energy requirement was similar and identical to the percentage of women found in the obese BF percentage groups, respectively. Dietary intake was compared with NZ guidelines, revealing that both groups of women consumed inadequate carbohydrate. In contrast, both groups consumed excess total and saturated fat, and sodium in excess of the upper level, mostly due to high intakes of takeaways. Takeaways were also the top contributor of total energy (13.4%), protein (13.4%) and fat (17.7%) in Pacific women. Obese Māori women consumed more takeaways (42.7%) than non-obese. Obese Pacific women consumed more discretionary breads, cereals and starchy foods (e.g. iced buns, croissants and paraoa parai (fry bread)) (210%) than non-obese. Recommendations include reducing takeaways, fats (e.g. butter), and sugar-sweetened beverages. Instead, opt for more complex carbohydrates and leafy green vegetables. Further research should investigate relationships between dietary intake and waist circumference, as well as other factors influencing body composition, such as physical activity and level of deprivation

A Fundamental Theorem for submanifolds of multiproducts of real space forms

We prove a Bonnet theorem for isometric immersions of submanifolds into the products of an arbitrary number of simply connected real space forms. Then, we prove the existence of associated families of minimal surfaces in such products. Finally, in the case of $\mathbb{S}^2\times\mathbb{S}^2$, we give a complex version of the main theorem in terms of the two canonical complex structures of $\mathbb{S}^2\times\mathbb{S}^2$

Associated Families of Immersions of Three Dimensional CR Manifolds in Euclidean Spaces

We consider isometric immersions in arbitrary codimension of three-dimensional strongly pseudoconvex pseudo-hermitian CR manifolds into the Euclidean space $\mathbb{R}^n$ and generalize in a natural way the notion of associated family. We show that the existence of such deformations turns out to be very restrictive and we give a complete classification.Comment: 15 page

Coupled elastic membranes model for quantum heat transport in semiconductor nanowires

Presented here is a nanowire model, consisting of coupled elastic membranes with the purpose of investigating thermal transport in quasi-one-dimensional quantum systems. The vibrations of each elastic membrane are quantized and the flow of the vibrational energy between adjacent membranes is allowed. The ends of the nanowire are attached to thermal baths held at different temperatures. We derived quantum master equation for energy flow across the nanowire and obtained thermal currents and other key observables. We study the effects of a disordered boundary on the thermal current by randomizing the membrane radii. We evaluate the model as a nanowire analogue as well as study the effects of a disordered boundary on thermal conductivity. The calculations show that the membrane lattice model demonstrates diameter phonon confinement and a severe reduction in thermal conductivity due to surface roughness which is characteristic of semiconductor nanowires. The surface roughness also produces a length dependence of the thermal conductivity of the form $\kappa=\alpha L^{\beta}$, with $\beta$ dependent on disorder characteristics, in the otherwise ballistic regime. Finally, the parameters of the model are fitted to available experimental data for silicon nanowires and the results of the calculations are assessed against the experimental data.Comment: 12 Pages, 10 Figure

Characteristics and Early Outcomes of Patients With Xpert MTB/RIF-Negative Pulmonary Tuberculosis Diagnosed During Screening Before Antiretroviral Therapy

Comparison of the characteristics of HIV-infected patients with Xpert-positive and Xpert-negative tuberculosis and relationship of Xpert status with subsequent clinical and programmatic outcomes