A Derivation of Three-Dimensional Inertial Transformations

The derivation of the transformations between inertial frames made by Mansouri and Sexl is generalised to three dimensions for an arbitrary direction of the velocity. Assuming lenght contraction and time dilation to have their relativistic values, a set of transformations kinematically equivalent to special relativity is obtained. The ``clock hypothesis'' allows the derivation to be extended to accelerated systems. A theory of inertial transformations maintaining an absolute simultaneity is shown to be the only one logically consistent with accelerated movements. Algebraic properties of these transformations are discussed. Keywords: special relativity, synchronization, one-way velocity of light, ether, clock hypothesis.Comment: 16 pages (A5), Latex, one figure, to be published in Found. Phys. Lett. (1997

Actualización en anticoncepción hormonal

La anticoncepción hormonal constituye el segundo método anticonceptivo más utilizado en nuestro país. Las principales novedades en cuanto a composición son la introducción del valerato de estradiol como componente estrogénico para mejorar la seguridad y de la drospirenona, progestágeno con acción antimineralocorticoide, que contrarresta la retención hidrosalina y ha sido aprobado como tratamiento del síndrome premenstrual. Para mejorar el cumplimiento se han propuesto el método de inicio inmediato y los regímenes de administración en ciclo prolongado o continuo que disminuyen los síntomas del periodo libre de hormona. La vía transdérmica presenta niveles séricos superiores de etinilestradiol que la oral lo que puede elevar el riesgo de tromboembolismo. Las innovaciones en la anticoncepción de emergencia son la pauta toma única de 1500 mcg de levonorgestrel y su dispensación sin receta. En este trabajo se revisan también los riesgos así como los criterios médicos de elegibilidad de la anticoncepción hormonalThe second more frequently used contraception method in our country is hormonal contraception. Innovations in composition include the introduction of estradiol valerate as estrogen element to improve safety, and oral contraceptives containing drospirenone that is a progestin with antimineraolcorticoid activity and has been approved for treating premenstrual syndrome. To improve compliance quick start and extended dose regimen, that decreases symptoms during hormonal free interval, have been proposed. With transdermal patch ethinylestradiol serum level is higher than with oral contraceptives therefore venous thromboembolism risk can be increased. Main innovations in emergency contraception are the 1500 mcg single dose of levonorgestrel regimen and the possibility of obtaining it without medical prescription. In this essay we also review severe adverse effects and medical eligibility criteria of hormonal contraceptio

A rotating cavity for high-field angle-dependent microwave spectroscopy of low-dimensional conductors and magnets

The cavity perturbation technique is an extremely powerful method for measuring the electrodynamic response of a material in the millimeter- and sub-millimeter spectral range (10 GHz to 1 THz), particularly in the case of high-field/frequency magnetic resonance spectroscopy. However, the application of such techniques within the limited space of a high-field magnet presents significant technical challenges. We describe a 7.62 mm x 7.62 mm (diameter x length) rotating cylindrical cavity which overcomes these problems.Comment: 11 pages including 8 figure

Change in quality of life among community-dwelling older adults: population-based longitudinal study.

This population-based study aimed to determine 5-year change in multidimensional QoL among community-dwelling older people, and to identify predictors of QoL change among demographic, socioeconomic, and health characteristics. Data of the 2011 and 2016 annual assessments of 1845 older men and women (age range 68-77 years) from the Lc65 + cohort study were used. QoL was assessed using a 28-item instrument yielding a QoL overall score and seven domain-specific QoL subscores. Additional ratings of QoL included a single item (excellent; very good; good; fair; poor), expected QoL in 1 year (better; worse; same as today), and retrospective assessment of QoL 5-year change (better; worse; same as 5 years ago). The predictors of 5-year change in the QoL score were assessed using linear regression, controlling for baseline QoL score. All prospective and retrospective indicators of QoL converged towards a slight deterioration over 5 years. QoL subscores significantly decreased in domains "Close entourage" (P = 0.004), "Social and cultural life" (P < 0.001), "Esteem and recognition" (P = 0.001), "Health and mobility" (P < 0.001), and "Autonomy" (P < 0.001), whereas "Material resources" (P = 0.345) and "Feeling of safety" (P = 0.380) remained stable. A stronger decrease in QoL was observed in the most vulnerable profiles at baseline in terms of demographic, socioeconomic, and health characteristics. Changes in depressive symptoms and in disability-either worsening or improving-predicted QoL change in the expected direction. Age-related decline in QoL may be limited through the prevention of disability and depressive symptoms, and more generally by devoting special attention to vulnerable profiles