Estimates of the dollar value of employee output in utility analyses: An empirical test of two theories.

Examined distributions of estimates of the dollar value of performance in studies employing the method of F. L. Schmidt et al (1979) for estimating the standard deviation of job performance (SDy) and found evidence that (1) the mean 50th percentile estimate is biased downward, (2) estimates of SDy appear to be a constant percentage of the 50th percentile estimate, and (3) estimates of SDy as a percentage of the 50th percentile value (SDp) are quite similar to empirical SDp values based on actual employee output. These findings suggest that the downward bias in the mean estimate of the 50th percentile causes the mean estimates of SDy to be similarly biased downward, but does not bias the estimates of SDp. Finally, an objective method for estimating the value of average employee output is described. The product of this value and the mean supervisory estimate of SDp yields an unbiased estimate of SDy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

N.m.r. study of the ferroelectric phase transition in a 7030mol% copolymer of vinylidene fluoride (VF2) and trifluoroethylene (TrFE)

Nuclear magnetic resonance (n.m.r.) studies of ¹⁹F nuclei in a $\text{70}\text{30}\text{mol}\text{\%}$ random copolymer of vinylidene fluoride and trifluoroethylene were performed at 9.14 MHz and 20.0 MHz. The free induction decays (FIDs) were analysed in terms of two T₂ components attributed to the amorphous and crystalline portions of the polymer. The changes in crystallinity as well as the effects of the ferroelectric transition were observed during cycles of heating and cooling between 20°C and 140°C. The crystalline component of the FID lengthens by a factor of 2 at 100°C on heating and decreases by this factor at 60°C on cooling, thus exhibiting the thermal hysteresis of this ferroelectric transition. The spin-lattice relaxation was also investigated. From measurements at 9.14 MHz the observed longitudinal relaxation time T₁ appears to be dominated by the dynamics of the amorphous phase and exhibits no anomaly through the phase transition. However, from measurements at 20 MHz, well defined minima of T₁ were observed, which are associated with the ferroelectric transition (especially after repeated annealing of the samples). Results are discussed in terms of the crystalline phase structure, which appears dynamically disordered above the ferroelectric phase transition. An analogy is considered with the plastic phase transitions encountered in molecular crystals.     

Parallel Pattern-Based Systems for Computational Biology: A Case Study

Computational biology research is now faced with the burgeoning number of genome data. The rigorous postprocessing of this data requires an increased role for high-performance computing (HPC). Because the development of HPC applications for computational biology problems is much more complex than the corresponding sequential applications, existing traditional programming techniques have demonstrated their inadequacy. Many high level programming techniques, such as skeleton and pattern-based programming, have therefore been designed to provide users new ways to get HPC applications without much effort. However, most of them remain absent from the mainstream practice for computational biology. In this paper, we present a new parallel pattern-based system prototype for computational biology. The underlying programming techniques are based on generic programming, a programming technique suited for the generic representation of abstract concepts. This allows the system to be built in a generic way at application level and, thus, provides good extensibility and flexibility. We show how this system can be used to develop HPC applications for popular computational biology algorithms and lead to significant runtime savings on distributed memory architectures.     

Nephropathy of type II diabetes: evidence for hereditary factors?

Family studies point to an important genetic element in the genesis of diabetic nephropathy, but it is not known whether renal abnormalities are present prior to the onset of diabetes. To address this issue we examined all consecutive patients suffering from type II diabetes with a duration of more than 10 years who attended a diabetes outpatient clinic. Ninety-four patients had nephropathy, 307 did not. All offspring who were phenotypically normal (no hypertension, normal oral glucose tolerance, non-smoking) and agreed to participate were examined, 26 from nephropathic and 30 from non-nephropathic diabetic parents. They were compared with 30 offspring matched for age, gender and BMI from non-diabetic parents as controls. We measured urinary albumin excretion under baseline conditions and at several time points after ingestion of 300 g cooked beef and submaximal treadmill exercise, respectively. In addition, casual blood pressure, ambulatory blood pressure, urinary albumin and urinary alpha-1-microglobulin were measured. Primary renal disease was excluded by clinical examination. Under baseline conditions, median urinary albumin excretion rate (AER; microgram/min) was significantly (P < 0.005) higher in offspring of nephropathic type II diabetic patients (7.8; range 1.04 to 19.5) than in the offspring of non-nephropathic type II diabetic patients (4.8; 0.36 to 17.5) and controls (4.4; 0.16 to 18.4). Submaximal treadmill exercise caused a greater proportional increase of AER in offspring of nephropathic type II diabetics (median 16-fold) than in offspring of non-nephropathic diabetic patients (6.3-fold) or controls (4.8-fold). In offspring of nephropathic diabetic patients casual and particularly ambulatory systolic blood pressures were significantly higher, but AER was not correlated with blood pressure. In summary, higher values, albeit within the normal range, for baseline and postexercise albuminuria were noted in phenotypically normal offspring of parents with type II diabetes and nephropathy. The observation suggests that changes in transglomerular albumin traffic are demonstrable prior to the onset of diabetes and diabetic nephropathy in subjects with a potential genetic predisposition to these conditions.     

Estimation of sampling error variance in the meta-analysis of correlations: Use of average correlation in the homogeneous case.

The estimate of the population correlation used in the formula for sampling error variance of a correlation is typically the observed correlation, but in meta-analysis the average of the observed correlations can be used. For the case in which there is no variation in the study population correlations or sample sizes and the number of studies is very large, the authors found that use of the average correlation estimator is more accurate than use of the traditional, individual correlation estimator, except in those rare cases in which the uncorrected population correlation is greater than .60. For typical sample sizes, when the uncorrected population correlation is between -.40 and .40, there is virtually no error in the meta-analysis credibility interval based on the average correlation estimator. On the other hand, the amount of the error in the individual correlation estimator is qualitatively important if the sample is 25 or less and the population correlation is less than .40. (PsycINFO Database Record (c) 2010 APA, all rights reserved)