Cortical Responses in Rats Predict Perceptual Sensitivities to Complex Sounds.

The common assumption that perceptual sensitivities are related to neural representations of sensory stimuli has seldom been directly demonstrated. The authors analyzed the similarity of spike trains evoked by complex sounds in the rat auditory cortex and related cortical responses to performance in an auditory task. Rats initially learned to identify 2 highly different periodic, frequency-modulated sounds and then were tested with increasingly similar sounds. Rats correctly classified most novel sounds; their accuracy was negatively correlated with acoustic similarity. Rats discriminated novel sounds with slower modulation more accurately than sounds with faster modulation. This asymmetry was consistent with similarities in cortical representations of the sounds, demonstrating that perceptual sensitivities to complex sounds can be predicted from the cortical responses they evoke. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence of frequent integration of non-T-DNA vector backbone sequences in transgenic strawberry plant

We have studied the occurrence of the integration of non-T-DNA sequences in transgenic strawberry plants obtained through Agrobacterium inoculation. DNA from these plants was subjected to PCR amplification of the sequence of the gene trfA, which is located outside the T-DNA. The percentage of trfA-positive plants varied from 40% to 90%, with a mean of 65.7%. Backbone sequences were confirmed by Southern blot analysis.     

Polycrystalline SrBi2Ta0.8Nb1.2O9 thin films

Abstract

The growth, microstructure and micro-Raman properties of SrBi₂Tao_0.8Nb_1.2O₉ (SBTN) thin films deposited on Si(100) substrates using pulsed laser deposition (PLD) technique were studied at various substrate temperatures. Films were characterized using X-ray diffraction(XRD), atomic force microscopy(AFM), energy dispersive X-ray analysis (EDAX) and micro-Raman studies. AFM studies indicated that the average grain size of the films increased between 0.08 μm to 0.1 μm with the increasing growth temperatures. Micro-Raman studies of SBTN films revealed the fact that shifting of Raman modes corresponds to the BO₆ (where B' Ta/Nb) octahedral symmetry, to higher frequencies, is in accordance with the different masses of the B site atoms and the force constants involved due to Nb doping at Ta sites.     

Glycerol polymerization degree effect on the emulsifying properties of polyglycerol esters

Polymeric emulsifiers based on glycerol and oleic acid were developed and their properties evaluated in palm oil and water solutions. Developed polymeric emulsifiers were polyglycerol-esters. Polymerization degree of polyglycerol-esters at different dosages (from 0.2 to 3% w/v) had a significant effect over emulsion stability, water surface tension, droplet size, and viscosity. Polyglycerol-ester with highest polymerization degree behaved more efficiently as emulsifier. A dosage of 0.5% w/v was required to maintain emulsion stability for a half-life period of 872 min (~14.5 h); which, is 5.6 and 3.6-fold longer stability than with the other two polyglycerol-esters developed. When dosage increased to 3% w/v, the emulsion stability also increased to 3792 min (~2.6 days). Nevertheless, surfactants with lower polymerization degree and molecular weight did not behave the same way. Emulsifier with highest polymerization degree reduced water surface tension by 70% and the mean particle diameter decreased when emulsifier polymerization degree increased. For the viscosity parameter, there were two interesting regions: for shear rates up to 1 s⁻¹ the emulsion behaved as Non-Newtonian fluid type Shear-thinning; while, higher shear rates, the viscosity exhibited a Newtonian profile.     

Profile of a population using a primary health care center in Puerto Rico

PURPOSE: To describe the services delivered by the Family Medicine Physicians at a Community Health Center. METHODS: All information from patient visits during the natural year 1996 were registered using a commercialized computer program. The information was gathered by different means: initial interview, physician's report, records, and personal interviews. RESULTS: A total of 13,203 visits were registered; this represent a total of 4,493 patients. Most of the patients were women, and with a mean age of 38. As expected, most of the patients have Medicaid. The most common conditions seen were hypertension, diabetes, and respiratory diseases. The mean number of visits during the year for almost all conditions was three. Most of the children and adolescents visit the Center due to respiratory conditions, while adults come due to hypertension, diabetes, and musculoskeletal conditions.     

Primary hyperparathyroidism due to parathyroid carcinoma

OBJECTIVES: Our aim was to determine whether tissue factor pathway inhibitor (TFPI), a physiologically important natural anticoagulant that acts by inhibiting the extrinsic pathway, concentrations decrease as liver disease progresses, and, second, whether TFPI has an etiologic role in portal vein thrombosis in cirrhotics. METHODS: After taking their informed consent, we determined TFPI concentrations in the plasma of healthy subjects (group I) (n = 15) (average age, 45.1 = 11.8 yr), cirrhotics (group II) (n = 16) (average age, 43.6 +/- 9.8 yr), and cirrhotics with portal vein thrombosis (group III) (n = 12) (average age, 42.6 +/- 10.7 yr). Mean and median TFPI values and interquartile ratios were determined for groups I, II, and III. Then group II and III were further divided according to the Child classes A, B, or C, and mean and median TFPI values and interquartile ratios were determined for these classes as well. Using the Man-Whitney U test, we compared the results. RESULTS: Statistically important differences were documented (p = 0.005) between the median TFPI levels of healthy adults and Child C cirrhotics (concentration lower in Child C) and between normal subjects and cirrhotics with portal vein thrombosis (p = 0.02) (TFPI concentration being lower in the latter group again). CONCLUSIONS: TFPI concentration decreases in advanced liver disease, and this may be a contributory factor for portal vein thrombosis in at least some cases of cirrhotics.     

NP-hardness of the stable matrix in unit interval family problem in discrete time

We show that to determine if a family of matrices, each with parameters in the unit interval, contains a matrix with all eigenvalues inside the unit circle is an NP-hard problem. We also discuss how this problem is closely related to the widespread problem of power control in wireless systems.     

Impact of flip-chip packaging on copper/low-k structures

Copper/low-k structures are the desired choice for advanced integrated circuits (ICs). Nevertheless, the reliability might become a concern due to the considerably lower strength and greater coefficient of thermal expansion (CTE) of the low-k materials. To ensure successful integration of the new chips within advanced packaging products, it is essential to understand the impact of packaging on chips with copper/low k structures. In this study, flip-chip die attach process has been studied. Multilevel, multiscale modeling technique was used to bridge the large gap between the maximum and minimum dimensions. Interface fracture mechanics-based approach has been used to predict interface delamination. Both plastic ball grid array (PBGA) and ceramic ball grid array (CBGA) packages were evaluated. Critical failure locations and interfaces were identified for both packages. The impact of thin film residual stresses has been studied at both wafer level and package level. Both PBGA and CBGA packaging die-attach processes induce significantly higher crack driving force on the low-k interfaces than the wafer process. CBGA die-attach might be more critical than PBGA die-attach due to the higher temperature. During CBGA die-attach process, the crack driving force at the low-k/passivation interface may exceed the measured interfacial strength. Two solutions have been suggested to prevent catastrophic delamination in copper/low-k flip-chip packages, improving adhesion strength of low-k/barrier interface or adding tiles and slots in low-k structures to reduce possible area for crack growth.     

Nephrotic syndrome in autosomal dominant polycystic kidney disease

Urinary protein excretion is generally less than 1 g/24 h in autosomal dominant polycystic kidney disease (ADPKD), and the association of the nephrotic syndrome with this condition is considered rare. A patient with ADPKD associated with nephrotic-range proteinuria is described. She exhibited a relatively rapid impairment of her renal function. An open renal biopsy revealed focal segmental glomerulosclerosis (FGS) with features consistent with secondary FGS. Twenty-one patients with ADPKD and nephrotic syndrome were retrieved from the literature. Fourteen of them (including this case) had a histopathologic evaluation, and FGS was the dominant diagnoses (five patients). Next in frequency were minimal-change disease and membranous nephropathy, with two patients each. Five other patients had a variety of diagnoses. Thus, it is difficult to ascertain if these associations are coincidental or represent a specific pathogenetic relationship. The evaluation of the data also suggests that the presence of proteinuria and nephrotic syndrome accelerates the course of ADPKD toward ESRD.