Beta cloth durability assessment for Space Station Freedom (SSF) Multi-Layer Insulation (MLI) blanket covers

MLI blankets for the Space Station Freedom (SSF) must comply with general program requirements and recommendations for long life and durability in the low-Earth orbit (LEO) environment. Atomic oxygen and solar ultraviolet/vacuum ultraviolet are the most important factors in the SSF natural environment which affect materials life. Two types of Beta cloth (Teflon coated woven glass fabric), which had been proposed as MLI blanket covers, were tested for long-term durability in the LEO environment. General resistance to atomic oxygen attack and permeation were evaluated in the high velocity atomic oxygen beam system at Los Alamos National Laboratories. Long-term exposure to the LEO environment was simulated in the laboratory using a radio frequency oxygen plasma asher. The plasma asher treated Beta cloth specimens were tested for thermo-optical properties and mechanical durability. Space exposure data from the Long Duration Exposure Facility and the Intelsat Solar Array Coupon were also used in the durability assessment. Beta cloth fabricated to Rockwell specification MBO 135-027 (Chemglas 250) was shown to have acceptable durability for general use as an MLI blanket cover material in the LEO environment while Sheldahl G414500 should be used only in locations which are protected from direct Ram atomic oxygen

Action towards hope: Addressing learner behaviour in a classroom

Unruly learners and disciplinary problems are an intractable part of every teacher’s teaching experience. It appears that, even though most schools have enacted a code of conduct to regulate learner behaviour, this does not always have the desired effect. Disciplinary problems in schools impact negatively on the teaching and learning environment as well as on teachers’ personal and professional well-being and morale. Framed within the context of a biblical worldview, this article narrates the experiences of one teacher who decided to take action towards hope. The situation in her classroom was quite desperate with learners coming to school unprepared and behaving very badly and parents being uninterested in the performance of their children at school. She realised that she could not change the learners or their parents unless she started with herself. In this context, she, as a postgraduate student under the supervision of the co-authors, embarked on an action-research project to promote positive learner behaviour. By collaborating with the learners on a set of classroom rules, engaging in reflective teaching and changing her own behaviour towards the learners, the situation in her classroom improved. Based on her experiences, this article argues that teachers should empower themselves with knowledge and a better understanding of the concept of discipline rather than viewing the classroom as a battlefield. It is important to acknowledge and show respect and appreciation for each learner in his or her own context

Recombinant alpha-interferon as salvage therapy in multiple myeloma

Ten patients with end-stage multiple myeloma refractory to conventional chemotherapy and hemibody irradiation received recombinant α-interferon as salvage therapy. The median duration of treatment was 8 weeks. One patient had an objective response and survived 8 months, whereas in the remaining 9 patients the disease progressed and median survival was 11,5 weeks. Side-effects were substantial and included confusion with extreme weakness, resulting in 5 patients refusing further therapy. The low response rate and the morbidity in this pilot study resulted in its discontinuation and the conclusion that recombinant α-interferon as singleagent therapy used for salvage in patients with refractory myeloma is of no value.S Afr Med J 1989; 76: 100-10

Severe acute respiratory infection with influenza A (H1N1) during pregnancy

The original publication is available at http://www.samj.org.zaABSTRACT FROM JOURNAL: Pregnant women are at high risk of severe acute respiratory infection if infected with the influenza A (H1N1) virus. On 14 August 2009 the first complicated H1N1 obstetric patient was admitted to the obstetric critical care unit (OCCU) at Tygerberg Hospital with respiratory distress. The clinical picture was that of bronchopneumonia, and she tested positive for H1N1. Subsequent pregnant patients admitted to the OCCU with respiratory compromise or flu symptoms were screened for the virus. Eleven days later 13 cases were confirmed. Five patients had acute lung injury and required ventilation and inotropic support. Three of the patients with acute lung injury subsequently died. Three patients required continuous positive airway pressure (CPAP) support only, with no inotropics needed. The remaining 5 patients presented early, received oseltamivir within 48 hours and did not require critical care admission. All the patients admitted to the OCCU and the medical intensive care unit (ICU) initially presented with flu symptoms, respiratory distress and changes on the chest radiograph indicating an active diffuse pulmonary parenchymal process. Six patients underwent uncomplicated caesarean sections for fetal distress after they were stabilised. Maternal and neonatal outcomes varied. The key factor appears to be early clinical diagnosis and oseltamivir within 48 hours of the onset of symptoms. The demographic data and maternal and fetal outcomes are set out in Table I

Coupling constants and transition potentials for hadronic decay modes of a meson

Within the independent-harmonic-oscillator model for quarks inside a hadron, a rigorous method is presented for the calculation of coupling constants and transition potentials for hadronic decay, as needed in a multi-channel description of mesons.Comment: 19 pages, 4 figure

On the validity of the reduced Salpeter equation

We adapt a general method to solve both the full and reduced Salpeter equations and systematically explore the conditions under which these two equations give equivalent results in meson dynamics. The effects of constituent mass, angular momentum state, type of interaction, and the nature of confinement are all considered in an effort to clearly delineate the range of validity of the reduced Salpeter approximations. We find that for $J\not{\hspace*{-1.0mm}=}0$ the solutions are strikingly similar for all constituent masses. For zero angular momentum states the full and reduced Salpeter equations give different results for small quark mass especially with a large additive constant coordinate space potential. We also show that $\frac{1}{m}$ corrections to heavy-light energy levels can be accurately computed with the reduced equation.Comment: Latex (uses epsf macro), 24 pages of text, 12 postscript figures included. Slightly revised version, to appear in Phys. Rev.

Management of trypanosomiasis and leishmaniasis

<p>Background: The current treatments for human African trypanosomiasis (HAT), Chagas disease and leishmaniasis (collectively referred to as the kinetoplastid diseases) are far from ideal but, for some, there has been significant recent progress. For HAT the only advances in treatment over the past two decades have been the introduction of an eflornithine/nifurtimox co-administration and a shorter regime of the old standard melarsoprol.</p> <p>Sources of data: PubMed.</p> <p>Areas of Agreement: There is a need for new safe, oral drugs for cost-effective treatment of patients and use in control programmes for all the trypanosomatid diseases.</p> <p>Areas of controversy: Cutaneous leishmaniasis is not on the agenda and treatments are lagging behind.</p> <p>Growing points: There are three compounds in development for the treatment of the CNS stage of HAT: fexinidazole, currently due to entry into phase II clinical studies, a benzoxaborole (SCYX-7158) in phase I trials and a diamidine derivative (CPD-0802), in advanced pre-clinical development. For Chagas disease, two anti-fungal triazoles are now in clinical trial. In addition, clinical studies with benznidazole, a drug previously recommended only for acute stage treatment, are close to completion to determine the effectiveness in the treatment of early chronic and indeterminate Chagas disease. For visceral leishmaniasis new formulations, therapeutic switching, in particular AmBisome, and the potential for combinations of established drugs have significantly improved the opportunities for the treatment in the Indian subcontinent, but not in East Africa.</p> <p>Areas timely for developing research: Improved diagnostic tools are needed to support treatment, for test of cure in clinical trials and for monitoring/surveillance of populations in control programmes.</p&gt

First Order Vortex Dynamics

A non-dissipative model for vortex motion in thin superconductors is considered. The Lagrangian is a Galilean invariant version of the Ginzburg--Landau model for time-dependent fields, with kinetic terms linear in the first time derivatives of the fields. It is shown how, for certain values of the coupling constants, the field dynamics can be reduced to first order differential equations for the vortex positions. Two vortices circle around one another at constant speed and separation in this model.Comment: 22pages, no figures, tex fil

Instantaneous Bethe-Salpeter equation: utmost analytic approach

The Bethe-Salpeter formalism in the instantaneous approximation for the interaction kernel entering into the Bethe-Salpeter equation represents a reasonable framework for the description of bound states within relativistic quantum field theory. In contrast to its further simplifications (like, for instance, the so-called reduced Salpeter equation), it allows also the consideration of bound states composed of "light" constituents. Every eigenvalue equation with solutions in some linear space may be (approximately) solved by conversion into an equivalent matrix eigenvalue problem. We demonstrate that the matrices arising in these representations of the instantaneous Bethe-Salpeter equation may be found, at least for a wide class of interactions, in an entirely algebraic manner. The advantages of having the involved matrices explicitly, i.e., not "contaminated" by errors induced by numerical computations, at one's disposal are obvious: problems like, for instance, questions of the stability of eigenvalues may be analyzed more rigorously; furthermore, for small matrix sizes the eigenvalues may even be calculated analytically.Comment: LaTeX, 23 pages, 2 figures, version to appear in Phys. Rev.