K-means method for rough classification of R&D employees' performance evaluation

This paper proposes an approach that can roughly cluster a data set with fuzzy linguistic entries as a prior data arrangement for performance evaluation of R&D employees. The extension principles of fuzzy linguistic numbers are used to modify the K‐means method for handling the linguistic data set. We define the absolute difference of fuzzy linguistic variables as their fuzzy distance. Based on this definition, the K‐means approach can be modified slightly for clustering purposes. The performance of employees engaged in designing and R&D‐oriented jobs is possibly related to some qualitative attributes and the evaluation of such attributes for each employee has a tendency toward semantic scales. In the proposed approach, the supervisor can evaluate the performance of each employee directly with a semantic scale. The modified K‐means approach can roughly cluster their performance into different classes in advance of applying some other sophisticated processes.     

High-efficiency InGaN-GaN MQW green light-emitting diodes with CARTand DBR structures

Distributed Bragg reflector (DBR) and charge asymmetric resonance tunneling (CART) structures were applied to nitride-based green light-emitting diodes (LEDs) to enhance their output efficiency It was found that we can reduce the forward voltage at 20 mA from 3.7 to 3.2 V with the inclusion of CART structure. It was also found that the electroluminescence peak wavelength of the CART LED is less sensitive to the amount of injection current. The output power and external quantum efficiency of the CART LED with DBR structure measured at 20 mA can reach 7.2 mW and 11.25%, respectively     

Characterization of Si implants in p-type GaN

Si ion implantation into p-type GaN followed by rapid thermal annealing (RTA) in N/sub 2/ has been performed. X-ray diffraction analyses indicate that ion-implanted damage remains even with 1050/spl deg/C, 60 s RTA. By varying implantation and postimplantation annealing conditions, we could convert carrier concentration from p-type 3 /spl times/ 10/sup 17/ cm/sup -3/ into n-type 2 /spl times/ 10/sup 17/ cm/sup -3/ /spl sim/2 /spl times/ 10/sup 19/ cm/sup -3/. It was found that typical activation energies of Si implants in p-GaN are lower than 10 meV. Such activation energies are smaller than those observed from epitaxially grown Si-doped GaN films. A deep donor level with activation energy of 60 meV was also found from some samples. Photoluminescence studies show that the peak appears at 372 nm might be related to implantation-induced defects. It was also found that a green emission band could be observed from Si-implanted GaN. It was shown that such a green emission is related to the yellow band observed from epitaxially grown Si-doped GaN. The transport properties of these Si-implanted samples were also studied.     

Using Cpk index with fuzzy numbers to evaluate service quality

Service quality is measured by customers' satisfaction. Traditionally, the degree of satisfaction is calculated from the data obtained from questionnaires that have been filled by customers directly. The percentile of each different level of a customer's satisfaction is employed to summarize and compare the quality of service provided by different enterprises. This approach does not consider the consistency of the customers' perceptions, thus making comparison difficult. This paper introduces the concept of a process capability index that considers both the average and the consistency of the data simultaneously. Evaluations of service quality are usually vague and linguistic. We use the fuzzy numbers of linguistic variables developed in fuzzy set theory to modify the process capability index, and then apply it to evaluate the quality of a service. The average and consistency of the data obtained from a service quality evaluation are thus considered simultaneously, making the comparison of the performance of service quality easier. Moreover, the value of the index can be applied to help to point out the direction for improving the performance of service quality whenever it is lower than some default value.     

The relationship of chronic mucin secretion to airway disease in normal and CFTR-deficient mice

In the cystic fibrosis (CF) patient, lung function decreases throughout life as a result of continuous cycles of infection, particularly with Pseudomonas aeruginosa and Staphylococcus aureus. The mechanism underlying the pathophysiology of the disease in humans has not been established. However, it has been suggested that abnormal, tenacious mucus, resulting perhaps from improper hydration from loss of Cl- secretion via the cystic fibrosis transmembrane conductance regulator (CFTR) protein, impairs clearance of bacteria from the CF airway and provides an environment favorable to bacterial growth. If this hypothesis is correct, it could explain the absence of respiratory disease in CFTR-deficient mice, since mice have only a single submucosal gland and display few goblet cells in their lower airways, even when exposed to bacteria. To test this hypothesis further, we induced allergic airway disease in CFTR-deficient mice. We found that induction of allergic airway disease in mice, unlike bacterial infection, results in an inflammatory response characterized by goblet cell hyperplasia, increased mucin gene expression, and increased production of mucus. However, we also found that disease progression and resolution is identical in Cftr-/- mice and control animals. Furthermore, we show that the presence of mucus in the Cftr-/- airway does not lead to chronic airway disease, even upon direct inoculation with S. aureus and P. aeruginosa. Therefore, factors in addition to the absence of high levels of mucus secretion protect the mouse from the airway disease seen in human CF patients.     

Meta-analysis of multiple outcomes by regression with random effects

Earlier work showed how to perform fixed-effects meta-analysis of studies or trials when each provides results on more than one outcome per patient and these multiple outcomes are correlated. That fixed-effects generalized-least-squares approach analyzes the multiple outcomes jointly within a single model, and it can include covariates, such as duration of therapy or quality of trial, that may explain observed heterogeneity of results among the trials. Sometimes the covariates explain all the heterogeneity, and the fixed-effects regression model is appropriate. However, unexplained heterogeneity may often remain, even after taking into account known or suspected covariates. Because fixed-effects models do not make allowance for this remaining unexplained heterogeneity, the potential exists for bias in estimated coefficients, standard errors and p-values. We propose two random-effects approaches for the regression meta-analysis of multiple correlated outcomes. We compare their use with fixed-effects models and with separate-outcomes models in a meta-analysis of periodontal clinical trials. A simulation study shows the advantages of the random-effects approach. These methods also facilitate meta-analysis of trials that compare more than two treatments.     

Is preoperative chemotherapy in locally advanced non-small-cell bronchial carcinoma of value?

Although surgeons are able to resect completely locally advanced non-small cell lung cancer with mediastinal lymph node involvement (stage IIIA), the majority of patients succumb from metastatic disease. Therefore, neoadjuvant therapy was introduced in the management of this disease in order to eradicate distant metastases at an early stage. Phase II trials with preoperative chemotherapy in stage IIIA patients have shown that the pathological response (amount of tumour necrosis) and the clearance of mediastinal lymph node correlate with a better survival and is the best predictor for eradication of distant metastases. Indeed, three small randomised phase III studies have demonstrated a survival advantage for preoperative chemotherapy compared to surgery alone. Further studies are required to determine the best neoadjuvant regimen inducing the largest amount of tumour necrosis.     

Rabies virus quasispecies: implications for pathogenesis

Passage of the mouse-adapted rabies virus strain CVS-24 (where CVS is challenge virus standard) in BHK cells results in the rapid selection of a dominant variant designated CVS-B2c that differs genotypically and phenotypically from the dominant variant CVS-N2c present in mouse-brain- or neuroblastoma-cell-passaged CVS-24. The glycoprotein of CVS-B2c has 10 amino acid substitutions compared with that of CVS-N2c. Because CVS-B2c can be reproducibly selected in BHK cells, it is likely to be a conserved minor subpopulation of CVS-24. CVS-N2c is more neurotropic in vitro and in vivo than CVS-B2c, which replicates more readily in nonneuronal cells in vitro and in vivo. These characteristics appear to be relevant to the pathogenicity of the two variants. CVS-N2c is more pathogenic for adult mice than CVS-B2c. In contrast, CVS-B2c is more pathogenic for neonatal mice. These differences in pathogenicity are reflected in the selection pattern when mixtures of CVS-N2c and CVS-B2c were used to infect neonatal and adult mice. Although CVS-N2c was highly selected in adult mice, no selection for either variant was seen in neonates, suggesting that certain aspects of development, such as maturation of the nervous and immune systems, may contribute to the selection process. We speculate that the existence of different variants within a rabies virus strain may facilitate the virus in overcoming barriers to its spread, both within the host and between species.     

Swyer James syndrome following Mycoplasma pneumoniae pneumonia: report of one case

Systemic vasculopathy in patients with neurofibromatosis type 1 is rare. We describe a case of unusual cerebral and renal involvement in a young, 29-year-old patient, who died of a cerebral ischemic attack one year after our observation.