HDTV-putting you in the picture

Interest is now starting to be expressed in larger television displays, which fill more of the observer's field of view, and hence increase their level of involvement in the programme. Unfortunately, these large screens reveal only too clearly the restricted resolution and visible line structure of today's television standards. If the true benefit of large-screen displays is to be obtained, then the television standard itself must be changed to allow a higher definition to be achieved in the final image. Hence the term `high-definition television', or HDTV for short, has come to imply a television standard capable of being satisfactorily displayed in this way. The author investigates recent research of development into HDTV and discusses the desire for a unique, worldwide standard for HDTV programme production     

Axisymmetric stresses and displacements in a finite circular bar

The lateral surface is assumed to be traction free, whereas its end sections are subjected to prescribed tractions and/or displacements. A family of biorthogonal eigenfunctions are generated via Love's function. The problem is formally reduced to an infinite system of linear algebraic equations which can be solved two at a time in some cases and satisfactorily approximated by truncation in other cases. Two example problems are solved and selected numerical results are presented in graphical form.     

The genetics of specific reading disability

Members of the immediate families of twenty children with specific reading disability were examined to determine the prevalence of reading disability within the families. A procedure was developed for identifying adults who may have compensated for a disability manifested more clearly in childhood. Forty-five percent of 75 first-degree relatives of the parents were affected and there was a significantly greater number of affected male relatives than females. No single mode of genetic transmission is evident after inspection of the pedigrees. It is suggested that the disorder is genetically heterogeneous and that subgroups of disabled readers should be looked for.     

The persistence of asperities in indentation experiments

The possibility that asperity persistence in indentation experiments is explainable in terms of the plasticity mechanics of asperity interaction has been investigated both theoretically and by conducting experiments with model asperities. Some persistence is expected as a result of the interaction but the degree of persistence depends on the distribution of the size of the asperities on a surface. The lower limit of the ratio of the real to apparent area of contact in an indentation test is 0.5.     

Gender differences in self-disclosure to various target persons.

In Exp I, 54 male and 54 female undergraduates reported their willingness to self-disclose about 14 topics to each of 3 same-gender target persons: a stranger, an acquaintance, and an intimate friend. The data show an interaction of S's gender and target person, demonstrating that males are more willing than females to disclose to strangers and acquaintances, but females are more willing than males to disclose to intimates. The results suggest a tendency for men to avoid emotional intimacy with one another. Competition among men and homophobia are offered as explanations for this lack of intimacy among men. A 2nd experiment (69 males, 79 females), which included both same-gender and opposite-gender target persons, replicated the findings of Exp I but did not support the competition or homophobia explanations. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

United Kingdom Videotex Service and the European Unified Videotex Standard

Videotex was introduced in the United Kingdom in 1971 with the Prestel public videotex service display standard finalized in 1976. Shortly afterwards, a slightly enhanced but unfortunately incompatible test standard (Antiope) was introduced by France. In CEPT (the European PTT harmonizing body) work has been successfully undertaken to produce a considerably enhanced alphamosaic standard that is upwards compatible to both the Prestel and Antiope systems, and also with the relevant CCITT videotex recommendations. A number of European countries, including the Federal Republic of Germany and the United Kingdom, have announced intentions to adopt the new standard. It permits the introduction of videotex services using low-cost alphamosaic terminals, and is structured to allow the further compatible enhancements of geometric and photographic picture creation, when these methods receive international standardization.     

No Effect of Omega-3 Fatty Acid Supplementation on Cognition and Mood in Individuals with Cognitive Impairment and Probable Alzheimer’s Disease: A Randomised Controlled Trial

Findings from epidemiological and observational studies have indicated that diets high in omega-3 polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) may reduce the risk of cognitive decline and Alzheimer’s disease (AD). To determine if increasing intake of DHA and EPA through supplementation is beneficial to cognition and mood in individuals with cognitive impairment no dementia (CIND) or Alzheimer’s disease (AD) a four month, randomised, double-blind, placebo controlled study was conducted. Fifty-seven participants with CIND and nineteen with AD were randomised to receive either omega-3 PUFAs (600 mg EPA and 625 mg DHA per day) or placebo (olive oil) over a four month period. Elevating depleted levels of EPA and DHA through supplementation in individuals with CIND or AD was found to have negligible beneficial effect on their cognition or mood. These findings confirm an overall negligible benefit of omega-3 PUFA supplementation for those with cognitive impairment and dementia. More intervention studies need to be undertaken with longer study durations and larger sample sizes. It may prove fruitful to examine effects of different doses as well as effects in other dementia subtypes.     

Hypothalamic regulatory peptides and their receptors: Cytochemical studies of their role in regulation at the adenohypophyseal level

Hypothalamic regulatory peptides bind to specific receptors on target cells in the pituitary and control secretion. They in turn can be regulated at the pituitary level by steroid and peptide modulators. Affinity cytochemical techniques are important tools for the identification of specific target binding sites for these regulatory peptides. This presentation reviews the work in which potent, biotinylated ligands of gonadotropin releasing hormone (bio-GnRH), corticotropin releasing hormone (bio-CRH), and arginine vasopressin (bio-AVP) were applied to study the target cell responses. Bio-GnRH, bio-CRH, and bio-AVP bind to membrane receptors on specific anterior pituitary cells. Dual labeling for either gonadotropin or adrenocorticotropin (ACTH) antigens further identified the target cells. After 1–3 minutes, the label was in patches or capped on the surface. After 3 minutes, it was internalized in small vesicles and sent to receptosomes and vacuoles in the Golgi complex. Eventually the biotinylated peptides, or a metabolite, was found in the lysosomes (multivesicular bodies) and a subpopulation of secretory granules. The route and rate of uptake was similar to that described for the classical receptor-mediated endocytosis process. In contrast, intermediate lobe corticotropes internalized the bio-CRH in less than 1 minute. The route through the Golgi complex appeared to be bypassed. Instead the labeled peptide was in vesicles, on the membranes of scattered vacuoles, and in multivesicular bodies. Modulation of ligand binding by steroids showed that changes in receptor numbers correlated with changes in the number of cells that bound the ligand. In male rats, dihydrotestosterone reduced the percentage of GnRH-bound cells by 50%. Most of the reduction appeared in cells that stored luteinizing hormone (LH) antigens. In diestrous female rats, estradiol increased the percentage of bio-GnRH-bound cells. However, the steroid decreased the percentage of GnRH-bound cells in cells from proestrous rats. Glucocorticoids decreased the percentage of CRH-bound corticotropes in as little as 10 minutes. Potentiation of secretion by these ligands was correlated with increases in the percentage of ligand-bound cells. AVP pretreatment of corticotropes increased the percentage of cells that bound bio-CRH. It also increased the rate of receptor-mediated endocytosis of CRH and changed the route so that the Golgi complex was bypassed. This effect could be mimicked by activation of its second messengers (calcium and protein kinase C). Similarly, CRH pretreatment increased the percentage of corticotropes that bound AVP. Thyrotropin releasing hormone (TRH) pretreatment also increased the percentage of thyrotropes that bound AVP. Finally, calcium or sodium channel blockers altered CRH binding so that fewer cells were labeled. This binding by CRH was not dependent on extracellular calcium and tests with a calcium channel agonist showed that it was related to activation of calcium channels. To summarize, these affinity cytochemical studies have identified specific target cells in the pituitary for GnRH, CRH, and AVP. They have also identified heterogeneity in the population. They have demonstrated new information about the direct modulatory effects of steroids, ion channels, and neuropeptides on neuropeptide binding by subpopulations of these target cells.     

Fine friction cutting: a useful wear process

Friction cutting of metals was first reported almost 160 years ago. This review concentrates on its latest development, the slitting of nickel-chromium, titanium and ferrous alloys by toothless, water-cooled, mild steel discs spinning with a rim speed between 50 and 100 ms⁻¹. Slits an thin an 0.25 mm can be produced with little surface damage.Slitting occurs by adhesive wear. When oxidation leading to a mild wear state can be prevented, area slitting rates greater than 10 mm² s⁻¹ can be achieved: this is the case with nickel-chromium and titanium alloys and with soft or hardened stainless and tool steels. Oxidation cannot be prevented with carbon steels and most cast irons, so these metals cannot in general be slit usefully by fine friction cutting     

On the approximate numerical analysis of slip-line fields

An approximate numerical analysis of slip-line fields is presented which requires one tenth the computing time of the matrix operator method. The analysis retains the structure of the matrix method but the matrix operators for force and displacement calculation and for the calculation of slip-line curvatures are replaced by simple algebraic expressions. These are developed from the approximation that slip-line elements may be replaced by circular arcs.The approximations have been tested on slip-line fields for free machining and machining with applied chip tension in which the angular extents of the assumed arcs have been as large as 0.6 radians. They have been found to be adequate at a better than 5% degree of accuracy except for levels of friction stress between chip and tool greater than 80% of the chip material shear flow stress.