Spacelab experiment definition study on phase transition and critical phenomena in fluids: Interim report on experimental justification

Pure fluids and fluid mixtures near critical points are identified and are related to the progress of several disciplines. Consideration is given to thermodynamic properties, transport properties, and the complex nonlinear phenomena which occur when fluids undergo phase transitions in the critical region. The distinction is made between practical limits which may be extended by advances in technology and intrinsic ones which arise from the modification of fluid properties by the earth's gravitational field. The kinds of experiments near critical points which could best exploit the low gravity environment of an orbiting laboratory are identified. These include studies of the index of refraction, constant volume specific heat, and phase separation

Evaluation of a novel UHMWPE bearing for applications in precision slideways

This paper presents a novel slideway bearing design comprised of a thin-film (0.1 mm-0.2 mm) of ultra-high molecular weight polyethylene (UHMWPE) bound to a rigid hemispherical substrate. Two prototype bearing designs were fabricated and tested to characterize the coefficient of friction (dynamic and static) and wear of the polymer. In addition, similar bearings were incorporated into a kinematically constrained rectilinear carriage to determine the repeatability of motion during multiple traverses. The first bearing had a radius of curvature on the order of 2.38 mm incorporating an UHMWPE film thickness between 0.1 mm and 0.2 mm. The friction coefficient was measured to be between 0.155 and 0.189 for normal loads of 11.5 N and 2.2 N, respectively at a surface speed of 4.2 mm {center_dot} s{sup -1}. This bearing failed after a traverse of approximately 700 m at a load of 11.5 N. A similar evaluation procedure was carried out on a bearing of radius 6.35 mm resulting in a friction coefficient between 0.125 and 0.185 at loads of 27.8 N and 2.2 N, respectively, and the bearing endured a traverse of over 2.2 km at a load of approximately 28 N (in both air and vacuum conditions) with a surface speed of 4.2 mm {center_dot} s{sup -1}. The second bearing prototype was further subjected to a repeatability test. In this setup, a carriage incorporating five bearings was traversed in a nominally linear path while vertical deviations for multiple traverses were measured by a custom built displacement sensor. Deviations from a linear path were observed to repeat to within a few nanometers about nominal variations of less than 10 nm for a traverse distance of 10 mm. This system and other subsystems used to characterize the friction coefficient and noise of the polymer bearing are presented

Evaluation of the use of pharmacological treatment with prisoners experiencing high levels of hypersexual disorder

This paper presents an evaluation of the impact of pharmacological treatment in reducing hypersexual disorder in adult males who have been incarcerated following conviction for a sexual offence. The evaluation compares two types of pharmacological treatment, one of which is part of the current NICE guidance for treatment of hypersexuality (Antiandrogens), whilst the other type (SSRIs) is off-label use in the UK for hypersexuality. The participant pool comprised 127 adult male prisoners serving sentences for sexual offences in a UK prison. Participants had been voluntarily referred for pharmacological treatment to manage hypersexual disorder. The results demonstrated a significant reduction of hypersexual disorder pre- and post-medication and contribute to the evidence base for the use of pharmacological treatment with individuals for whom hypersexual disorder may be a salient factor in their offending. Limitations of the current research are discussed

Early testing of a coarse/fine precision motion control system

This abstract presents a brief overview of key components of a motion control stage for accurate nanometer level positioning for scanning specimens over an area measuring 50 mm x 50 mm. The completed system will utilize a short-range, third generation 6 degree-of-freedom fine motion control platform (4 microns, 160 micro-radians) carried by a long-range, two-axis x-y positioning system (50 mm x 50 mm). Motion of the controlled platform relative to a measurement frame will be measured using a heterodyne laser interferometer and capacitance sensing. The final stage will be mounted onto an isolation table in a vacuum chamber, itself on isolation supports mounted to a granite slab on bed rock and isolated from the main floor of the building. This whole system is housed in a temperature-controlled laboratory. It is envisaged that the current system will provide the ability to ''pick and place'' at nanometer levels and be used for long range scanning of specimens (including biological specimens), micro- /macroassembly, lithography and as a coordinate measuring machine (CMM). Furthermore, the system performance will be compared with other comparable systems at international locations such as, National Physical Laboratory (NPL) in the UK, Technical University of Eindhoven (TUE) in the Netherlands, Physikalisch-Technische Bundesanstalt (PTB) in Germany, and our own sub-atomic measuring machine (SAMM) [1, 2] at UNC-Charlotte. Critical requirements of the system are as follows: (1) Vacuum compatible to better than 20 mPa; (2) Range of 50 mm x 50 mm x 4 microns; (3) Maximum translation velocity of 5 mm {center_dot} s{sup -1}; (4) Sub-nanometer resolution; and (5) System accuracy of better than 10 nm

Controller strategy for a 6 DOF piezoelectric translation stage

A controller for the third generation, 6 degree-of-freedom (DOF) piezoelectric translation stage shown in Figure 1 is presented. This was tested by monitoring all six coordinate motions using an orthogonal array of six, high-resolution capacitance gages. The full 6 DOF matrix transformations and controller block diagrams for this system have been measured and the system operated under closed loop control. Results of early experiments to determine the 21 open loop response functions as well as preliminary results showing the closed loop response for the 3 linear translations are presented in this abstract. The ultimate goal of this project is to incorporate this 6 DOF stage within a long range X-Y scanning system for nanometer pick-and-place capability over an area of 50 x 50 mm. The control strategy and early results from this system will be presented

A comparison of drive mechanisms for precision motion controlled stages

This abstract presents a comparison of two drive mechanisms, a Rohlix{reg_sign} drive and a polymer nut drive, for precision motion controlled stages. A single-axis long-range stage with a 50 mm traverse combined with a short-range stage with a 16 {micro}m traverse at a operational bandwidth of 2.2 kHz were developed to evaluate the performance of the drives. The polymer nut and Rohlix{reg_sign} drives showed 4 nm RMS and 7 nm RMS positioning capabilities respectively, with traverses of 5 mm at a maximum velocity of 0.15 mm{sup -}s{sup -1} with the short range stage operating at a 2.2 kHz bandwidth. Further results will be presented in the subsequent sections

Estimation of uncertainty in three-dimensional coordinate measurement by comparison with calibrated points

This paper details a method of estimating the uncertainty of dimensional measurement for a three-dimensional coordinate measurement machine. An experimental procedure was developed to compare three-dimensional coordinate measurements with calibrated reference points. The reference standard used to calibrate these reference points was a fringe counting interferometer with a multilateration-like technique employed to establish three-dimensional coordinates. This is an extension of the established technique of comparing measured lengths with calibrated lengths. Specifically a distributed coordinate measurement device was tested which consisted of a network of Rotary-Laser Automatic Theodolites (R-LATs), this system is known commercially as indoor GPS (iGPS). The method was found to be practical and was used to estimate that the uncertainty of measurement for the basic iGPS system is approximately 1 mm at a 95% confidence level throughout a measurement volume of approximately 10 m × 10 m × 1.5 m. © 2010 IOP Publishing Ltd

A wirelessly powered and controlled device for optical neural control of freely-behaving animals

Optogenetics, the ability to use light to activate and silence specific neuron types within neural networks in vivo and in vitro, is revolutionizing neuroscientists' capacity to understand how defined neural circuit elements contribute to normal and pathological brain functions. Typically, awake behaving experiments are conducted by inserting an optical fiber into the brain, tethered to a remote laser, or by utilizing an implanted light-emitting diode (LED), tethered to a remote power source. A fully wireless system would enable chronic or longitudinal experiments where long duration tethering is impractical, and would also support high-throughput experimentation. However, the high power requirements of light sources (LEDs, lasers), especially in the context of the extended illumination periods often desired in experiments, precludes battery-powered approaches from being widely applicable. We have developed a headborne device weighing 2 g capable of wirelessly receiving power using a resonant RF power link and storing the energy in an adaptive supercapacitor circuit, which can algorithmically control one or more headborne LEDs via a microcontroller. The device can deliver approximately 2 W of power to the LEDs in steady state, and 4.3 W in bursts. We also present an optional radio transceiver module (1 g) which, when added to the base headborne device, enables real-time updating of light delivery protocols; dozens of devices can be controlled simultaneously from one computer. We demonstrate use of the technology to wirelessly drive cortical control of movement in mice. These devices may serve as prototypes for clinical ultra-precise neural prosthetics that use light as the modality of biological control.National Institutes of Health (U.S.) (NIH Director’s New Innovator Award (DP2OD002002))National Institutes of Health (U.S.) (Grant 1R01DA029639)National Institutes of Health (U.S.) (Grant 1RC1MH088182)National Institutes of Health (U.S.) (Grant 1RC2DE020919)National Institutes of Health (U.S.) (Grant 1R01NS067199)National Institutes of Health (U.S.) (Grant 1R43NS070453)National Science Foundation (U.S.) (CAREER award)National Science Foundation (U.S.) (NSF Grant DMS 1042134)National Science Foundation (U.S.) (NSF Grant DMS 0848804)National Science Foundation (U.S.) (NSF Grant EFRI 0835878)Benesse FoundationGoogle (Firm)Dr. Gerald Burnett and Marjorie BurnettUnited States. Dept. of Defense (CDMRP PTSD Program)Massachusetts Institute of TechnologyBrain & Behavior Research FoundationAlfred P. Sloan FoundationSociety for NeuroscienceMassachusetts Institute of Technology. Media LaboratoryMcGovern Institute for Brain Research at MITWallace H. Coulter Foundatio

Cambio demográfico, migración y salud reproductiva : el papel de las mujeres senegalesas en la constitución de las familias

En aquest paper presentem en primer lloc els trets més característics de la transició de la nupcialitat i de la fecunditat a Senegal fent referència a alguns indicadors de la salut sexual i reproductiva de les dones. A continuació presentem els indicadors que resumeixen la biografia migratòria, nupcial i reproductiva d'un col·lectiu de dones senegaleses que han immigrat a Catalunya i que estan construint les seves famílies a cavall de dues cultures i de dos continents, fent referència entre altres coses a la poligamia, al lloc de naixement i residència dels seus fills i a la utilització de mètodes de planificació familiar. Acabem la comunicació amb algunes reflexions sobre el paper de les dones com agents actius en les decisions en materia de sexualitat i reproducció, en una societat que no és la seva, de la qual agraeixen els serveis de salut públics però sense deixar de banda la seva pròpia concepció de la família i de la salut.En este artículo presentamos en primer lugar los elementos más rellevantes de la transición de la nupcialidad y de la fecundidad en Senegal haciendo referencia a algunos indicadores de salud sexual y reproductiva de las mujeres. A continuación presentamos los indicadores que resumen la biografía migratoria, nupcial y reproductiva de un colectivo de mujeres de Senegal que han inmigrado a Cataluña y que están formando sus familias en el contexto de dos culturas y de dos continentes, haciendo referencia entre otras cosas a la poligamia, al lugar de nacimiento y residencia de sus hijos y a la utilización de métodos de planificación familiar. Finalizamos la comunicación con algunas reflexiones sobre el papel de las mujeres como agentes activos en las decisiones en materia de sexualidad y reproducción, en una sociedad que no es la suya propia, de la que agradecen los servicios de salud públicos pero sin olvidar su propia concepción de la familia y de la salud.In this paper we present the main characteristics from Senegal's nuptuality and fertility transition according to a group of measures related to women's sexual and reproductive health. We then show those indicators that summarise Senegal's women biography in terms of their migration, nuptuality and reproduction for those who have immigrated to Catalunya and have to raise a family between two cultures and two continents. In this way the article makes reference, among other things, to polygamy, the birthplace and residence of their offspring, as well as the existence of family planning. Lastly, we finish this paper with some ideas about the role of Senegal's women making sexual and reproduction decisions in a different society where they can obtain public health services while keeping their own approach to family and health issues