Realisation of the circulator concept using differential-input operational amplifiers

A 3-port unit that satisfies the requirements of the circulator concept is realised with a differential-input operational amplifier. It provides, between two of its ports, a direct measure of reflection coefficient at the third port. One unit may be employed as a hybrid transformer; two or more units may be connected in a ring to form an n-port circulator.     

The effect of human chorionic gonadotrophin on the expression of progesterone receptors in human luteal cells in vivo and in vitro

The human corpus luteum expresses genomic progesterone receptors (PRs) suggesting that progesterone may have an autocrine or paracrine role in luteal function. We hypothesised that the reduction in luteal PR reported in the late-luteal phase augmented progesterone withdrawal and had a role in luteolysis. We therefore tested the hypothesis that luteal rescue with human chorionic gonadotrophin (hCG) would maintain PR expression. PR was immunolocalised to different cell types in human corpora lutea (n = 35) from different stages of the luteal phase and after luteal rescue with exogenous hCG. There was no change in the staining intensity of theca-lutein cell or stromal cell PR throughout the luteal phase or after luteal rescue. In the late-luteal phase, granulosa-lutein cell PR immunostaining was reduced (P < 0.05) but the trend to reduction was also seen after luteal rescue with hCG (P = 0.055). To further investigate the effect of hCG on granulosa-lutein cell PR expression, an in vitro model system of cultured human luteinised granulosa cells was studied. Cells were cultured for 12-13 days exposed to different patterns of hCG and aminoglutethamide to manipulate progesterone secretion (P < 0.0001). Expression of PR A/B and PR B isoforms was examined by quantitative real-time RT-PCR. PR A/B mRNA was lower (P < 0.05) after 11-13 days of culture than after 7 days of culture. This reduction could not be prevented by hCG in the presence (P < 0.05) or absence (P < 0.05) of stimulated progesterone secretion. The expression of PR B mRNA showed a similar pattern (P = 0.054). Simulated early pregnancy in vivo and hCG treatment of luteinised granulosa cells in vitro did not appear to prevent the down-regulation of PR seen during luteolysis.     

The role of liquid crystals in the formation of graphitizable carbons (cokes)

The formation of cokes and graphites proceeds via the creation from the isotropic fluid phase of carbonization of pitch and coal, of lamellar nematic liquid crystals or mesophase. This anisotropic fluid, deformable mesophase, develops as spheres within which constituent molecules are stacked parallel to an equatiorial plane. This type of structure facilitates coalescence to a coherent mass which eventually forms a graphitisable carbon. The ‘onion-skin’ structure of mesophase spheres cannot so coalesce. Different optical textures of cokes and graphites owe their origin to different chemical reactivities and fluidities of mesophase, the lower the fluidity the smaller the size of the optical texture. Mesophase from lameller molecules is compared with conventional rod-like nematic liquid crystals. Structures in needle-cokes, metallurgical coke, coke from solvent refiend coal and carbon fibre from pitch are discussed in terms of formation and properties of lamellar nematic liquid crystals.     

Teaching machines and programmed instruction: Areas of application.

One of the principal enterprises of publishers and equipment producers is the manufacture and sale of programs and teaching machines. Applications of these educational and training techniques are prevalent in education, special education, industry, and the military. Conflicting results have been obtained both within and among these areas. It is concluded that this lack of concordance is due both to the situation in which the technique is used and various programming technicalities. More control in future research concerning criterion tests, structuring of this situation, control groups, specification of objectives, motivational factors, and theoretical variables is recommended. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neuroticism and disclosure reciprocity.

49 male undergraduates identified as either "normal" or "neurotic" by their scores on the Maudsley Personality Inventory were exposed to a confederate who disclosed either intimate or superficial information about himself, as part of an "impression formation" study. Normal males reciprocated disclosure at a level of intimacy similar to the confederates, but neurotics disclosed at a moderate level regardless of whether the confederate's initial disclosure was intimate or superficial. Results suggest that neuroticism may be related to inappropriate or nonnormative disclosure, rather than characteristically high or low levels of disclosure. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Burstiness and resource management in ATM networks

Networks based upon the asynchronous transfer mode (ATM) provide for high flexibility to cope with a wide range of applications, some of them producing highly sporadic traffic. Therefore, the problem of burstiness has become in the last few years a key issue for such networks. A basic question is how to dimension network buffers in the presence of bursty traffic? In this paper we investigate the concept of burstiness and its impact on resource management. In burstiness characterization encountered in the literature, special attention has been given to the squared coefficient of variation of inter-arrival time Cv² in a cell arrival process. In order to observe the impact of bursty traffic on a queue, we develop in the present paper a ‘bursty’ traffic model, namely the two-stage hyper-Bernoulli cell arrival process, HBP₂, for short. We numerically solve the HBP₂/D/1/K queue. We especially derive the rejection probability P_loss. Numerical results are then thoroughly studied and we discuss the relevance for burstiness characterization of Cv² and peak to mean rate ratio B. We draw attention to the concept of local overload, i.e. when the arrival rate is greater than the server rate. This seems to be the most relevant phenomenon in the impact of a bursty traffic on a queue. These results are finally applied to the problem of resource management in ATM networks.     

Sexual assault history and physical health in randomly selected Los Angeles women.

Associations of sexual assault history with multiple measures of physical health were examined among 1,610 randomly selected women living in Los Angeles, California. Sexually assaulted women were more likely than nonassaulted women to report poor health perceptions, functional limitation, several chronic diseases, medically explained somatic symptoms, and medically unexplained somatic symptoms. Sexual assault was associated with increased risk of symptoms in a variety of organ systems rather than solely reproductive or sexual symptoms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microbiological assessment of the Gouda-type cheese-making process in a Venezuelan industry

The adoption of the Hazard Analysis and Critical Control Point (HACCP) system is necessary to assure the safety of the product in the cheese-making industry. The compliment of pre-requisite programs as Good Manufacture Practices (GMPs) and Sanitation Standard Operating Procedures (SSOPs) are required before the implementation of the HACCP plan. GMPs are the standards related to equipments, tools, personnel, etc. SSOPs are the procedures related to hygiene and sanitation of the plant and workers. The aim of this study was to assess the compliment of the pre-requisite programs and the microbiological conditions of the Gouda type cheese-making process in a Venezuelan processing plant before designing a HACCP plan. Samples were: (a) raw milk, pasteurized milk, curd and ripened cheese, (b) water, (c) environment of the production areas and ripening premises, (d) equipments before and after sanitation, (e) food handlers. Microbiological analyses were done according to COVENIN standards. This study showed that even though pasteurization process was effective to kill pathogen bacteria of the raw milk and the water was safe, however there are deficient manufacture practices in the hygiene as well as in sanitation of the plant and food handlers. Prerequisite programs (GMP-SSOP) of this industry need to be well established, controlled and evaluated.