Analysis of the /spl Sigma/-/spl Delta/ pulsed digital oscillator for MEMS

The aim of this paper is the analysis, simulation, and experimental verification of the /spl Sigma/-/spl Delta/ pulsed digital oscillator (PDO) topology. As it has been shown in previous works, the oscillation frequency and output spectrum in the PDO depend on the sampling frequency, the natural frequency of the microelectromechanical systems (MEMS) resonator and its damping factor. Here, extensive discrete-time simulations have been carried out which show that the normalized oscillation frequency as a function of the normalized natural frequency of the resonator is very similar to a distorted Devil's Staircase fractal. This nonlinear behavior is a direct consequence of the damping losses of the MEMS resonator. Analytical conditions for a perfect oscillation at the natural frequency of the resonator are also calculated. For this set of what we call "perfect" frequencies, it is also shown that the energy transfer from the electrical to the mechanical domain is maximum. Then a more generalized structure of the oscillator is considered and the drawn conclusions are tested against experimental results obtained from an oscillator prototype which uses a MEMS resonator with thermoelectric actuation and piezoresistive position sensing.     

The microbiology of mixed salad containing raw and cooked ingredients without dressing

Growth of aerobic mesophilic bacteria in mixed salad without dressing, containing cooked sweet corn and raw endive, was similar to that of raw endive alone. At 9°C, sweet corn permitted the growth of the lactic acid bacterium Leuconostoc mesenteroides , whenever the bacterium was present on raw endive, whereas no growth of lactic acid bacteria was recorded on raw endive alone. Listeria monocytogenes , artificially inoculated in the samples, grew more in the mixed salad than in the raw endive alone, for products stored at 6°C and 9°C. Acidification of sweet corn to pH 5.0 was proposed to reduce the development of L. monocytogenes in the mixed salad to a level similar to that recorded in the raw endive alone. Acidification with citric acid reduced spoilage of sweet corn, whereas acetic acid caused necrosis on the leaves of raw endive.     

Fluorimetric methods for the measurement of intermediate metabolites (lactate,pyruvate, alanine, β-hydroxybutyrate,glycerol) using a COBAS FARA centrifugal analyser

Intermediate products of the metabolism of glucose, fat and amino-acid are important in the evaluation of such metabolic disorders as diabetes mellitus, liver disease and metabolic acidosis. In the present study, methods for the measurement of intermediate metabolites (lactate, pyruvate, alanine, β-hydroxybutyrate and glycerol) have been adapted to a fast centrifugal analyzer: the COBAS FARA. Correlation coeffcients rangedfrom 0.90 to 0.99, compared to established manual spectrophotometric methods. Within-run coeffcients of variation (CVs) ranged between 2.9 and 8.8% at low levels, between 1.5 and 5.7% at medium levels and between 1.2 and 5.6% at high levels. Between-run CVs were between 4.0 and 15.0% at low levels, between 1.7 and 7.0% at medium levels and between 1.3 and 2.7% at high levels. These fluorimetric assays for the determination of intermediate metabolites on COBAS FARA (Roche) have a good sensitivity and precision, are less costly than manual methods and can be used on a routine basis.     

Primary traits of Eysenck's P-E-N system: three- and five-factor solutions

The Eysenck Personality Profiler (EPP), a set of 21 scales measuring primary traits hypothesized to be definers of Neuroticism, Extraversion, and Psychoticism factors, was administered to 229 adults together with the Eysenck Personality Questionnaire--Revised (H. J. Eysenck & S. B. G. Eysenck, 1991) and the Revised NEO Personality Inventory (NEO-PI-R; P. T. Costa & R. R. McCrae, 1992b). Correlations of EPP scales with NEO-PI-R facet scales provided preliminary evidence supporting the convergent and discriminant validity of the EPP scales. However, varimax and targeted validimax factor analyses suggested that some EPP scales were misclassified and that EPP scales could better be understood in terms of the 5-factor model than the intended 3-factor model.     

Structure discovery in medical databases: a conceptual clustering approach

Clustering is an important data analysis tool for discovering structure in data sets. Although research on conceptual clustering has produced algorithms showing significant advantages over earlier numerical ones, existing methods still present some limitations regarding applicability to biomedical domains. In this paper we describe ADAGIO, a conceptual clustering algorithm combining a low-cost preordering process with a breadth-first incremental control strategy that incorporates merging and splitting operators. Experimental evaluation indicated that the algorithm achieves a good balance between structure discovery performance and computational efficiency, and demonstrated the comparative effectiveness of its missing information handling process. ADAGIO is able to handle qualitative, quantitative and mixed-type data. An application example to a cancer domain is given, where the algorithm was able to suggest interesting epidemiological interpretations.     

Protective factors in adolescent health behavior

The role of psychosocial protective factors in adolescent health-enhancing behaviors--healthy diet, regular exercise, adequate sleep, good dental hygiene, and seatbelt use--was investigated among 1,493 Hispanic, White, and Black high school students in a large, urban school district. Both proximal (health-related) and distal (conventionality-related) protective factors have significant positive relations with health-enhancing behavior and with the development of health-enhancing behavior. In addition, in cross-sectional analyses, protection was shown to moderate risk. Key proximal protective factors are value on health, perceived effects of health-compromising behavior, and parents who model health behavior. Key distal protective factors are positive orientation to school, friends who model conventional behavior, involvement in prosocial activities, and church attendance. The findings suggest the importance of individual differences on a dimension of conventionality-unconventionality. Strengthening both proximal and distal protective factors may help to promote healthful behaviors in adolescence.     

Breed group effects on milk production of Brazilian crossbred dairy cows

Lactation records (n = 2362) of 1402 crossbred cows in 22 cooperating dairy herds in southeastern Brazil were evaluated. Cows were mixtures of Zebu (Gir, Guzera, and unknown) and European breeding (mostly Holstein). Lactation milk yields were expressed as total, 3050-d, or deviated 305-d yields, either adjusted or unadjusted for days in milk (DIM). Mean DIM was 280. Arithmetic means unadjusted for DIM were 1942, 1666, and 5 kg per record. Milk yields of daughters from sires of 6/8 and 7/8 European breeds were higher than yields of daughters from sires of 5/8 European breeds when data were either adjusted or unadjusted for DIM. The differences associated with breed group of sire were only slightly reduced when records were adjusted for DIM. There was no evidence of a decline in milk yield as the fraction of European breeding of the sire increased from 6/8 to 7/8. For a given breed group of sire, whether the grandsire was purebred or crossbred had no detectable effect. These results should be useful in determining strategies for crossbreeding of dairy cows in tropical areas, particularly when crossbred sires are used.     

Carcinoma of the splenic flexure. Nosological and therapeutic contribution

Twenty-one patients undergoing colectomy for carcinoma of the splenic flexure from November 1996 throughout October 1993 were studied retrospectively. Clinical and prognostic features were compared with those of other colon cancers treated in the same period at the same Institution. No differences in symptoms at onset and stage distribution were found in the two groups. The complex removal of the cancer tissue was achieved with the resection of the major part of the transverse colon, splenic flexure, descending colon and its mesocolon. The splenic flexure cancer did not show a worse prognosis than other colon cancers.     

Development of novel, potent, and selective dopamine reuptake inhibitors through alteration of the piperazine ring of 1-[2-(diphenylmethoxy)ethyl]-and 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazines (GBR 12935 and GBR 12909)

The design, synthesis, and biological evaluation of compounds related to the dopamine (DA) uptake inhibitors: 1-[2-(diphenylmethoxy)ethyl]-4-(3-phenylpropyl)piperazine (1) and 1-[2-[bis-(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperazine (2) (GBR 12395 and GBR 12909, respectively), directed toward the development and identification of new ligands interacting with high potency and selectivity at the dopamine transporter (DAT) is reported. The substitution of the piperazine ring in the GBR structure with other diamine moieties resulted in the retention of the high affinity of new ligands for the DAT. Some of the modified GBR analogs (e.g. 8, 10, (-)-49, or (-)-50) displayed substantially higher selectivity (4736- to 693-fold) for the dopamine (DA) versus the serotonin (5HT) reuptake site than the parent compounds. The bis(p-fluoro) substitution in the (diphenylmethoxy)ethyl fragment slightly increased the affinity of the ligands at the DA reuptake site but reduced their selectivity at this site (e.g. 9 and 8, 11 and 10, or 17 and 16, respectively). Congeners, such as the series of monosubstituted and symmetrically disubstituted piperazines and trans-2,5-dimethylpiperazines, which lack the (diphenylmethoxy)ethyl substituent lost the affinity for the DAT yet exhibited very high potency for binding to the sigma receptors (e.g.28). The chiral pyrrolidine derivatives of 1, (-)-49, and (+)-49, exhibited an enantioselectivity ratio of 181 and 146 for the inhibition of DA reuptake and binding to the DAT, respectively.     

Optimization of the grapes reception process

Neural Computing and Applications - Grapes reception is a key process in wine production. The harvest days are extremely challenging days in managing the reception of the grapes, as the winery...