Quantum work fluctuations in connection with the Jarzynski equality.

A result of great theoretical and experimental interest, the Jarzynski equality predicts a free energy change ΔF of a system at inverse temperature ß from an ensemble average of nonequilibrium exponential work, i.e., 〈e^{-ßW}〉=e^{-ßΔF}. The number of experimental work values needed to reach a given accuracy of ΔF is determined by the variance of e^{-ßW}, denoted var(e^{-ßW}). We discover in this work that var(e^{-ßW}) in both harmonic and anharmonic Hamiltonian systems can systematically diverge in nonadiabatic work protocols, even when the adiabatic protocols do not suffer from such divergence. This divergence may be regarded as a type of dynamically induced phase transition in work fluctuations. For a quantum harmonic oscillator with time-dependent trapping frequency as a working example, any nonadiabatic work protocol is found to yield a diverging var(e^{-ßW}) at sufficiently low temperatures, markedly different from the classical behavior. The divergence of var(e^{-ßW}) indicates the too-far-from-equilibrium nature of a nonadiabatic work protocol and makes it compulsory to apply designed control fields to suppress the quantum work fluctuations in order to test the Jarzynski equality.

Cost analysis of integrating the PrePex medical device into a voluntary medical male circumcision program in Zimbabwe.

BACKGROUND: Fourteen African countries are scaling up voluntary medical male circumcision (VMMC) for HIV prevention. Several devices that might offer alternatives to the three WHO-approved surgical VMMC procedures have been evaluated for use in adults. One such device is PrePex, which was prequalified by the WHO in May 2013. We utilized data from one of the PrePex field studies undertaken in Zimbabwe to identify cost considerations for introducing PrePex into the existing surgical circumcision program. METHODS AND FINDINGS: We evaluated the cost drivers and overall unit cost of VMMC at a site providing surgical VMMC as a routine service ("routine surgery site") and at a site that had added PrePex VMMC procedures to routine surgical VMMC as part of a research study ("mixed study site"). We examined the main cost drivers and modeled hypothetical scenarios with varying ratios of surgical to PrePex circumcisions, different levels of site utilization, and a range of device prices. The unit costs per VMMC for the routine surgery and mixed study sites were $56 and $61, respectively. The two greatest contributors to unit price at both sites were consumables and staff. In the hypothetical scenarios, the unit cost increased as site utilization decreased, as the ratio of PrePex to surgical VMMC increased, and as device price increased. CONCLUSIONS: VMMC unit costs for routine surgery and mixed study sites were similar. Low service utilization was projected to result in the greatest increases in unit price. Countries that wish to incorporate PrePex into their circumcision programs should plan to maximize staff utilization and ensure that sites function at maximum capacity to achieve the lowest unit cost. Further costing studies will be necessary once routine implementation of PrePex-based circumcision is established.

Use of steel bands in sternotomy closure: implications in high-risk cardiac surgical population.

A retrospective-prospective descriptive and comparative study of two sternal closure techniques in a population of 621 patients divided into: group A, steel band closure (n=300) and group B, conventional technique closure (n=321), was carried out between January 2005 and December 2007 in order to describe and compare the results of both techniques in high-risk patients for sternal dehiscence and mediastinitis. Differences between both groups and association with risk factors were obtained using non-parametric tests for statistical analysis. No complications or mortality related to the use of the steel sternal bands were found. A statistically significant difference was found in the frequency of sternal dehiscence between both groups (P=0.022) in favor of group A. Although the frequency of mediastinitis was higher in group B, a statistically significant difference could not be established in terms of this complication. Sternal dehiscence was found to be a risk factor for mediastinitis. This study demonstrates that the use of steel bands for median sternotomy closure is a safe, reliable and reproducible technique. The frequency of sternal dehiscence significantly decreases with this technique in high-risk patients.

Integración docente-asistencial: una experiencia de educación continua para el personal de servicios: Colombia / Teaching care integration: an experience of continuing education to health personnel: Colombia

El artículo recoge una experiencia de integración docente-asistencial dirigida a personal perteneciente a puestos y centros de salud. La metodología educativa fue participativa y se lograron progresos importantes dentro del desarrollo de los agentes de salud (profesionales, técnicos, auxiliares y promotores). Sin embargo, los autores destacan que el proceso educativo, en sí mismo, no fue un factor que propiciara una mejor prestación de servicios e impactara cualitativamente en la dinámica asistencial (preventivo-curativa). Los factores determinantes están inscritos dentro de la organización social existente en Colombia, país donde se llevó a cabo el programa. Dentro de dicha organización es bastante improbable que nuevas modalidades en los procesos educativos tengan verdadera trascendencia debido a limitantes estructurales sociales, políticas y económicas que caracterizan el sistema colombiano