BACKGROUND AND OBJECTIVES Now nearly 2 decades into the laparoscopic era, nationwide laparoscopic cholecystectomy conversion rates remain around 5% to 10%. We analyzed patient- and surgeon-specific factors that may impact the decision to convert to open. METHODS We retrospectively analyzed 2205 LCs performed at a large tertiary community hospital over a 52 month period (May 2004 through Octob...

A mathematical model of the effects of interchromosomal biased gene conversion, mutation and natural selection on a multigene family is developed and analyzed. The model assumes two allelic states at each of n loci. The effects of genetic drift are ignored. The model is developed under the assumption of no recombination, but the analysis shows that, at equilibrium, there is no linkage disequili...

OBJECTIVE To analyze the preoperative factors contributing to the decision to convert laparoscopic to open cholecystectomy. METHODS Retrospective identification of 324 consecutive patients undergoing laparoscopic cholecystectomy, with univariate and multivariate analysis of the following parameters: age, gender, obesity, previous abdominal surgery, presentation with acute cholecystitis, pancr...

To assess the effects of livestock grazing on soil compaction (density changes), the trampling action of livestock was simulated. The research field was located to the south west of Nazarabad in Savojbolagh district, south west of Tehran Province. Samples were annually collected based on a completely randomized design. From the triple regions (reference, key and critical) 36 cylindrical cores w...

Evaluation of disease outcome is central to the assessment of tuberculosis (TB) control programmes. In the study reported in this article we examined the factors influencing the measurement of outcome, survival rates during and after treatment, smear conversion rates, and relapse rates for patients diagnosed with TB in a rural area of Malawi between 1986 and mid-1994. Patients with less certain...

The measurement of (86)Rb turnover recently has been suggested as a useful method for measuring field metabolic rate in small animals. We investigated a proposed mechanism of (86)Rb turnover, its analogy to K(+), by comparing the turnover of (86)Rb in a model insect, the rhinoceros beetle Xylotrupes gideon, fed a diet of plum jam or plum jam enriched with K(+) or Rb(+). The turnover of (86)Rb i...

Repeatability studies are gaining considerable interest among physiological ecologists, particularly in traits affected by high environmental/residual variance, such as whole-animal metabolic rate (MR). The original definition of repeatability, known as the intraclass correlation coefficient, is computed from the components of variance obtained in a one-way ANOVA on several individuals from whi...

We present a simple quantum-field model for photon frequency conversion processes in dispersive dielectric microcavities, allowing practical calculations of conversion rates and efficiency optimization. The model incorporates the effect of dispersion into the structure of spatial cavity eigenmodes, while the material nonlinear properties enter the calculations through the coupling coefficients....

We study the influence of social networks on labor market transitions. We develop the first model where social ties and job status coevolve through time. Our key assumption is that the probability of formation of a new tie is greater between two employed individuals than between an employed and an unemployed individual. We show that this assumption generates negative duration dependence of exit...