Role of GABA in the control of thyrotropin secretion in the rat

Various doses of GABA from 0.25 to 5 mumol injected into the third ventricle decrease serum TSH rapidly. The same effect was observed with GABOB (10 mumol), the hydroxylated form of GABA. The inhibitory effect of both of these drugs was prevented by picrotoxin injection (1 microgram). Peripheral injection of GABAergic drugs such as GABOB or AOAA also decreased serum TSH. In vitro, the addition of GABA (from 6.7 . 10(-6) to 6.7 . 10(-4) M) to the incubation medium of hemi-anterior pituitary did not modify the liberation of TSH. To test the physiological role of GABA in the regulation of thyrotropin function the circadian TSH rhythm was used as a model. Both GABAergic inhibitors, picrotoxin (10 microgram/kg b.w.) as well as semicarbazide (150 mg/kg b.w.), induced an increase of the low basal nocturnal level of TSH (centered on the 02.00 h time point) without altering the diurnal peak of TSH. We conclude that GABA has an inhibitory effect on central thyrotropin control via an inhibition of TRH release from the hypothalamus and might be, at least partly, responsible for the low nocturnal levels of serum TSH observed during the circadian physiological rhythm.     

Assessment of cohesion and adaptability in component family dyads: A question of convergent and discriminant validity.

In the assessment of family cohesion and adaptability, researchers typically overlook the possibility that different components of the family may be more cohesive or adaptable than others. This potential problem is often compounded by monomethodism, reliance on a single source of information. Using a multitrait-mutimethod approach, we obtained three measures of cohesion and adaptability in three component dyads of relatively healthy families. Mothers, fathers, and college students reported about cohesion and adaptability in the mother–student, father–student, and mother–father relationships. Using confirmatory factor analysis, we found significant differences in the convergent validities of mothers', fathers', and students' reports. Furthermore, significant differences emerged among the correlations between mother–father, mother–student, and father–student cohesion (and adaptability), which suggests that noteworthy differences exist between family subsystems on these constructs. Implications for assessment strategies in marital and family counseling are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Relative Humidity on the Ultraviolet Induced Inactivation of Airborne Bacteria

Ultraviolet germicidal irradiation (UVGI) as an engineering control against infectious bioaerosols necessitates a clear understanding of environmental effects on inactivation rates. The response of aerosolized Serratia marcescens, Bacillus subtilis, and Mycobacterium parafortuitum to ultraviolet irradiation was assessed at different relative humidity (RH)levels in a 0.8 m³ completely-mixed chamber. Bioaerosol response was characterized by physical factors including median cell aerodynamic diameter and cell water sorption capacity and by natural decay and UV-induced inactivation rate as determined by direct microscopic counts and standard plate counts. All organisms tested sorbed water from the atmosphere at RH levels between 20% and 95% (up to 70% of dry cell mass at 95% RH); however, no concomitant change in median aerodynamic diameter in this same RH range was observed. Variations in ultraviolet spherical irradiance were minor and not statistically significant in the 20-95% RH range. Cell water sorption and inactivation response was similar for each of the pure cultures tested: when RH exceeded approximately 50%, sorption increased markedly and a sharp concurrent drop in UV-induced inactivation rate was observed.     

The nonsqueaky wheel

This paper presents a new approach, termed performance-based maintenance, can utilize past and ongoing equipment maintenance records to prioritize electrical distribution equipment with greater detail. The proposed scheme provides cost savings and useful in identifying equipment that can have a lesser level of future maintenance, or extended maintenance cycles. The integration of multiple inputs is required to minimize the risks associated with improper equipment prioritization. The savings can be redirected to areas such as predictive diagnostics, which can provide for greater improvements in reliability while also reducing the over all spend on maintenance.     

居民区雷电保护系统的试验:火箭触发雷电和电流冲击发生器试验数据的比较

We present a comparison of data obtained during testing of lightning protective system of a residential structure in rocket-triggered lightning experiment at the International Center for Lightning Research and Testing(ICLRT)at Camp Blanding,Florida,and current surge generator experiment at Rzeszow University of Technology in Poland.Three different configurations of LPS were tested in Poland with the dc grounding resistances of the entire system 4.09 Ω(LPS 1a),1.65 Ω(LPS 1b),and 2.88 Ω(LPS 2).For LPS 1a with three ground rods the value of the peak current entering the electrical circuit neutral was about 56% of the injected current peak,and for LPS 1b with two additional ground rods and two 5 m long buried horizontal conductors it was about 16%.For LPS 2 with five ground rods interconnected by a buried loop conductor this ratio was 21%.The current waveshapes in the ground rods differed from the injected current waveshapes and the current waveshapes in other parts of the test system,especially,for poorer-grounding LPS 1a.The surge-generator results are consistent with those of triggered-lightning experiments at Camp Blanding,Florida(DeCarlo et al.,2008 [2]).     

Convex and Semi-Nonnegative Matrix Factorizations

We present several new variations on the theme of nonnegative matrix factorization (NMF). Considering factorizations of the form X=FG^T, we focus on algorithms in which G is restricted to containing nonnegative entries, but allowing the data matrix X to have mixed signs, thus extending the applicable range of NMF methods. We also consider algorithms in which the basis vectors of F are constrained to be convex combinations of the data points. This is used for a kernel extension of NMF. We provide algorithms for computing these new factorizations and we provide supporting theoretical analysis. We also analyze the relationships between our algorithms and clustering algorithms, and consider the implications for sparseness of solutions. Finally, we present experimental results that explore the properties of these new methods.     

Social influences related to college students’ use of Macintosh computers on an all-PC campus

In the present qualitative research study, 35 Mac users were interviewed in a university campus that exclusively supports PC machines. We particularly explored the Mac-users’ social influences, saving technological and other influences for future reports. Results showed Mac users to possess significant connections with other Mac users on the university campus. The Mac users in our study indicated that positive, past exposure, including Apple’s advertising of Macs, had sharp influences on their decisions to become and remain Mac users.