Survey and Service on STD/HIV/AIDS in Namungo Mines,Lindi Region

Namungo is small-scale mining in Ruangwa district, Lindi Region, with deposits of green gemstone (tsavorite). About 400 men and women are living in temporary settlements. In August 2001, an STD/HIV/AIDS workplace intervention started which comprised of: A baseline KAP study with villagers and miners, A survey on infection rates with Syphilis and HIV, Treatment of patients with STD, An educational campaign and Development of plans for continuos collaboration between the mine and the health system. The KAP-study showed that 81% of respondents knew that sexual intercourse/sex without a condom is the main mode of HIV transmission. 80% correctly started that a person infected with HIV can remain a symptomatic for a long period. Half of them responded to had paid sex with more than one partner during the last 12 mouth. Those reporting having used a condom in the past 3 month were 48%. 92% of the respondents reported willingness for Voluntary Counseling and Testing (VCT) to know their HIV status. From 429 people who had came with symptoms of STDs most were treated for discharge syndrome (40% males,24 females) and for genital ulcers (38% in males and females) Testing and counseling for syphilis and HIV was offered to STD clients and volunteers. Infection rates were high in both groups, STD patients and volunteers with 18% for syphilis and 17% for HIV. The highest prevalence with 38% was found in women 30-34 years of age. The high infection rates, risky behavior and a high mobility of the people involved are a challenge to claim holders, health authorities and communities in the vicinity. Regular interventions urgently needed

On the origin of the extremely different solubilities of polyethers in water

The solubilities of polyethers are surprisingly counter-intuitive. The best-known example is the difference between polyethylene glycol ([–CH2–CH2–O–]n) which is infinitely soluble, and polyoxymethylene ([–CH2–O–]n) which is completely insoluble in water, exactly the opposite of what one expects from the C/O ratios of these molecules. Similar anomalies exist for oligomeric and cyclic polyethers. To solve this apparent mystery, we use femtosecond vibrational and GHz dielectric spectroscopy with complementary ab initio calculations and molecular dynamics simulations. We find that the dynamics of water molecules solvating polyethers is fundamentally different depending on their C/O composition. The ab initio calculations and simulations show that this is not because of steric effects (as is commonly believed), but because the partial charge on the O atoms depends on the number of C atoms by which they are separated. Our results thus show that inductive effects can have a major impact on aqueous solubilities

ICP polishing of silicon for high quality optical resonators on a chip

Miniature concave hollows, made by wet etching silicon through a circular mask, can be used as mirror substrates for building optical micro-cavities on a chip. In this paper we investigate how ICP polishing improves both shape and roughness of the mirror substrates. We characterise the evolution of the surfaces during the ICP polishing using white-light optical profilometry and atomic force microscopy. A surface roughness of 1 nm is reached, which reduces to 0.5 nm after coating with a high reflectivity dielectric. With such smooth mirrors, the optical cavity finesse is now limited by the shape of the underlying mirror

Caracterización térmica de placas de yeso con material de cambio de fase incorporado

En este trabajo se demuestra la idoneidad de incorporar materiales de cambio de fase en placas de yeso para incrementar su capacidad de almacenamiento térmico. Para ello se evalúa y se compara la capacidad de almacenamiento térmico, de diferentes elementos constructivos cuyo uso y aplicación es similar a la de las placas de yeso: trasdosado y tabique separador. Se ha disenado y puesto en funcionamiento una instalación experimental que simula las condiciones de contorno que se producen en una estancia donde estén instalados los diferentes materiales y sistemas constructivos. Se ha estudiado la influencia de diferentes para´metros y variables del sistema (temperatura de trabajo, velocidad del aire, presentación de los materiales de cambio de fase, ubicación en el edificio,…), para constituir un sistema de almacenamiento de calor latente, que, complementado con estrategias pasivas (captación solar, ventilación natural), reduzca las necesidades de consumo energético para la climatización de edificios. Se obtiene que las placas de yeso con un 45% en peso de material de cambio de fase es capaz de almacenar en 1,5 cm de espesor, 5 veces la energía térmica de un panel de yeso laminado con el mismo espesor, y la misma cantidad que 1/2 pie de fábrica ladrillo hueco sencillo, en el rango de temperaturas próximas a la de confort (20-30 ºC), manteniendo las propiedades físicas y mecánicas exigidas en la normativa

Self-localization of magnon Bose-Einstein condensates in the ground state and on excited levels: from harmonic to box-like trapping potential

Long-lived coherent spin precession of 3He-B at low temperatures around 0.2 Tc is a manifestation of Bose-Einstein condensation of spin-wave excitations or magnons in a magnetic trap which is formed by the order-parameter texture and can be manipulated experimentally. When the number of magnons increases, the orbital texture reorients under the influence of the spin-orbit interaction and the profile of the trap gradually changes from harmonic to a square well, with walls almost impenetrable to magnons. This is the first experimental example of Bose condensation in a box. By selective rf pumping the trap can be populated with a ground-state condensate or one at any of the excited energy levels. In the latter case the ground state is simultaneously populated by relaxation from the exited level, forming a system of two coexisting condensates.Comment: 4 pages, 5 figure

Wind Circulation in Selected Rotating Magnetic Early-B Stars

The rotating magnetic B stars have oblique dipolar magnetic fields and often anomalous helium and metallic compositions. These stars develop co-rotating torus-shaped clouds by channelling winds from their magnetic poles to an anchored planar disk over the magnetic equator. The line absorptions from the cloud can be studied as the complex rotates and periodically occults the star. We describe an analysis of the clouds of four stars (HD184927, beta Cep, sigma Ori E, and HR6684). From line synthesis models, we find that the metallic compositions are spatially uniform over the stars' surfaces. Next, using the Hubeny CIRCUS code, we demonstate that periodic UV continuum fluxes can be explained by the absorption of low-excitation lines. The analysis also quantifies the cloud temperatures, densities, and turbulences, which appear to increase inward toward the stars. The temperatures range from about 12,000K for the weak Fe lines up to temperatures of 33,000K for N V absorptions, which is in excess of temperatures expected from radiative equilibrium. The spectroscopic hallmark of this stellar class is the presence of strong C IV and N V resonance line absorptions at occultation phases and of redshifted emissions at magnetic pole-on phases. The emissions have characteristics which seem most compatible with the generation of high-energy shocks at the wind-cloud interface, as predicted by Babel.Comment: 19 pages, Latex plus 6 figures A&A single-spaced, accepted by Astronomy & Astrophysics. Files available by ftp at nobel.stsci.edu/pub/aapaper

Glasslike Behavior in Aqueous Electrolyte Solutions

When salts are added to water, the viscosity generally increases suggesting the ions increase the strength of the water's hydrogen-bond network. However, infrared pump-probe measurements on electrolyte solutions have found that ions have no influence on the rotational dynamics of water molecules implying no enhance-ment or breakdown of the hydrogen-bond network. Here we report optical Kerr-effect and dielectric relaxa-tion spectroscopic measurements, which have enabled us to separate the effects of rotational and transitional motions of the water molecules. These data show that electrolyte solutions behave like a supercooled liquid approaching a glass transition in which rotational and translational molecular motions are decoupled. It is now possible to understand previously conflicting viscosity data, nuclear magnetic resonance relaxation, and ultrafast infrared spectroscopy in a single unified picture