About [q]-regularity properties of collections of sets

We examine three primal space local Hoelder type regularity properties of finite collections of sets, namely, [q]-semiregularity, [q]-subregularity, and uniform [q]-regularity as well as their quantitative characterizations. Equivalent metric characterizations of the three mentioned regularity properties as well as a sufficient condition of [q]-subregularity in terms of Frechet normals are established. The relationships between [q]-regularity properties of collections of sets and the corresponding regularity properties of set-valued mappings are discussed.Comment: arXiv admin note: substantial text overlap with arXiv:1309.700

Josephson tunneling of dark solitons in a double-well potential

We study the dynamics of matter waves in an effectively one-dimensional Bose-Einstein condensate in a double well potential. We consider in particular the case when one of the double wells confines excited states. Similarly to the known ground state oscillations, the states can tunnel between the wells experiencing the physics known for electrons in a Josephson junction, or be self-trapped. As the existence of dark solitons in a harmonic trap are continuations of such non-ground state excitations, one can view the Josephson-like oscillations as tunnelings of dark solitons. Numerical existence and stability analysis based on the full equation is performed, where it is shown that such tunneling can be stable. Through a numerical path following method, unstable tunneling is also obtained in different parameter regions. A coupled-mode system is derived and compared to the numerical observations. Regions of (in)stability of Josephson tunneling are discussed and highlighted. Finally, we outline an experimental scheme designed to explore such dark soliton dynamics in the laboratory.Comment: submitte

A thermal vacuum test optimization procedure

An analytical model was developed that can be used to establish certain parameters of a thermal vacuum environmental test program based on an optimization of program costs. This model is in the form of a computer program that interacts with a user insofar as the input of certain parameters. The program provides the user a list of pertinent information regarding an optimized test program and graphs of some of the parameters. The model is a first attempt in this area and includes numerous simplifications. The model appears useful as a general guide and provides a way for extrapolating past performance to future missions

Kinetics of nitric oxide formation and decomposition

Experiments on shock wave structure were conducted in the 12 inch shock tube facility, and it is shown that this work was motivated by the need for improved kinetics for the modeling of NO production in space shuttle flow fields. The experiments on shock structure involved simultaneous observations of pressure and temperature on the wall of the shock tube during reflection of normal shock waves in inert gases

An induction theorem and nonlinear regularity models

A general nonlinear regularity model for a set-valued mapping $F:X\times R_+\rightrightarrows Y$, where $X$ and $Y$ are metric spaces, is considered using special iteration procedures, going back to Banach, Schauder, Lusternik and Graves. Namely, we revise the induction theorem from Khanh, J. Math. Anal. Appl., 118 (1986) and employ it to obtain basic estimates for studying regularity/openness properties. We also show that it can serve as a substitution of the Ekeland variational principle when establishing other regularity criteria. Then, we apply the induction theorem and the mentioned estimates to establish criteria for both global and local versions of regularity/openness properties for our model and demonstrate how the definitions and criteria translate into the conventional setting of a set-valued mapping $F:X\rightrightarrows Y$.Comment: 28 page

A Comparison of Quartz Crystal Microbalance Measurements with Mass Spectrometer Determinations

An experimental program was undertaken in which mass accretion rates, as determined by a liquid nitrogen cooled quartz crystal microbalance, were compared with the mass flux rates, as determined by both a cycloidal type and a quadrupole type residual gas analyzer for five simple materials. The data indicate a high degree of correlation between these instruments insofar as the shape of the curves. There are large variations however among the absolute values

The invisible children - protecting the right to birth registration in South Africa

Birth registration is fundamentally important for the protection of the rights of children. It is the key that unlocks their fundamental rights. Children without birth certificates can be regarded as “invisible”. Given the importance of birth registration, the United Nations Children’s Fund set a target to achieve universal birth registration (i.e., birth registration for all children) by 2030. This target flows from the adoption of the Sustainable Development Goals (SDGs) by the United Nations General Assembly in 2015. The SDGs includes a dedicated target in goal 16 to provide a legal identity for all, including birth registration, by 2030. South Africa’s birth registration rate has remained stagnant at 88.6 per cent from 2011 to 2016. (This figure will be reviewed when the Census 2022 data becomes available.) Although South Africa’s birth registration rate is higher compared to some other countries in Africa, it still falls short of the UNICEF target of universal birth registration. This article centres around the overarching question as to whether the legislative framework for birth registration in South Africa is optimal for achieving the UNICEF target of universal birth registration by 2030. It starts off with an investigation of the causes of low birthregistration rates and the concomitant classes of children who are vulnerable to low birth-registration rates. Next, the importance of birth registration and the devastating consequences of failure to obtain a birth certificate are considered. This is followed by a review of the relevant provisions of international human rights instruments and the Constitution of the Republic of South Africa, 1996. Next, the legal framework, particularly the Births and Deaths Registration Act 51 of 1992 and its regulations are critically analysed, with a view to identifying inadequacies in legislation, improper implementation of legislation, and failure to remove limitations and barriers to birth registration. Finally, recommendations are made for law and policy reforms to remedy these shortfalls

Evaluation of waist-to-height ratio to predict 5 year cardiometabolic risk in sub-Saharan African adults

Simple, low-cost central obesity measures may help identify individuals with increased cardiometabolic disease risk, although it is unclear which measures perform best in African adults. We aimed to: 1) cross-sectionally compare the accuracy of existing waist-to-height ratio (WHtR) and waist circumference (WC) thresholds to identify individuals with hypertension, pre-diabetes, or dyslipidaemia; 2) identify optimal WC and WHtR thresholds to detect CVD risk in this African population; and 3) assess which measure best predicts 5-year CVD riskPeer reviewedFinal Accepted Versio

Vier sleutelareas van die onderwys in ’n nuwe staatkundige bedeling in Suid-Afrika

Quite a few changes have occurred in South Africa since 2 February 1990 - even in the field o f education. The greatest changes in education, however, still lie ahead. Thus the present fifteen education departments will probably be replaced by one education system an d regional departments. A few important challenges for education include, inter alia, the financial situation, in which providing for the best possible education with the little money that is available, will have to be planned. In addition the rate o f population growth is very high. A new education structure will make greater demands in regard to a heterogeneous school population and multicultural education. Education standards will also have to be maintained as far as certification and the professional quality o f the teachers are concerned. In the meantime it remains important that education is still provided on the basis o f sound educational principles - this includes education through the medium o f the home language, the construction and maintenance o f the spirit and character o f the school, the continuation o f the culture o f the parental home in the school and the involvement and responsibility o f parents in the education. These aims will have to be promoted purposefully