A novel facility for reduced-gravity testing: A setup for studying low-velocity collisions into granular surfaces.

This work presents an experimental design for studying low-velocity collisions into granular surfaces in low-gravity. In the experiment apparatus, reduced-gravity is simulated by releasing a free-falling projectile into a surface container with a downward acceleration less than that of Earth's gravity. The acceleration of the surface is controlled through the use of an Atwood machine, or a system of pulleys and counterweights. The starting height of the surface container and the initial separation distance between the projectile and surface are variable and chosen to accommodate collision velocities up to 20 cm/s and effective accelerations of ∼0.1 to 1.0 m/s(2). Accelerometers, placed on the surface container and inside the projectile, provide acceleration data, while high-speed cameras capture the collision and act as secondary data sources. The experiment is built into an existing 5.5 m drop tower frame and requires the custom design of all components, including the projectile, surface sample container, release mechanism, and deceleration system. Data from calibration tests verify the efficiency of the experiment's deceleration system and provide a quantitative understanding of the performance of the Atwood system.

[Physician-patient relations in the outpatient clinic of primary health care units]. / Relación entre médico y paciente en la consulta externa de unidades de primer nivel de atención médica.

The objective of this study was to determine the degree of concordance between physicians and patients at primary health care units with regard to different aspects of medical consultation. The research design was a descriptive survey. The study units were the primary health care units of the Ministry of Health located in the "Gustavo A. Madero" district. 76 patients were interviewed as well as those physicians who gave consultations. A questionnaire was administered to those patients. It included six questions on the following aspects: physical examination, explanation regarding illness and drug prescription, degree of compliance by patients, duration of consultation and an estimation to know if the physician-patient relationship was satisfactory. For these measurements a analogue-visual scale and a semantic differential scale were used. A great variation was found in the correlation between physician and patient. The major degree of concordance was obtained in the way the relationship was perceived by each other (rs = 0.18); the estimation of compliance (rs = 0.10) and the explanation about illness (rs = 0.08). A tendency to disagreement was perceived in the physical examination (rs = 0.18), the duration of consultation (rs = 0.10) and the explanation about drugs (rs = -0.02). A larger degree of agreement was observed when the physician was less than 40 years old, when he had no specialty and when the patients was also less than 40 years old.