195 resultados para Lindsay, D. Michael
Resumo:
We characterize asymmetric equilibria in two-stage process innovation games and show that they are prevalent in the different models of R&D technology considered in the literature. Indeed, cooperation in R&D may be accompanied by high concentration in the product market. We show that while such an increase may be profitable, it may be socially inefficient.
Resumo:
Background: There is growing evidence that vitamin D is active in the brain but until recently there was a lack of evidence about its role during brain development. Guided by certain features of the epidemiology of schizophrenia, we have explored the role of vitamin D in the developing brain and behaviour using whole animal models. Methods: Sprague-Dawley rats were fed a vitamin D deficient diet (DVD) or control diet 6 weeks prior to mating and housed under UVB-free lighting conditions. On the day of birth all rats were fed a control diet for the remainder of the study. We observed behaviour at two timepoints; on the day of birth to study maternal behaviour, and at 10 weeks of age to study offspring behaviour in adulthood, under baseline and drug induced conditions (MK-801, haloperidol, amphetamine). Results: Prenatal vitamin D deficiency results in subtle alterations in maternal behaviour as well as long lasting effects on the adult offspring, despite a return to normal vitamin D levels during postnatal life. These affects were specific to transient prenatal vitamin D depletion as adult vitamin D depletion, combined prenatal and chronic postnatal vitamin D depletion, or ablation of the vitamin D receptor in mice led to markedly different outcomes. Conclusions: The developmental vitamin D (DVD) model now draws strength from epidemiological evidence of schizophrenia and animal experiments. Although the DVD model does not replicate every aspect of schizophrenia, it has several attractive features: (1) the exposure is based on clues from epidemiology; (2) it reproduces the increase in lateral ventricles; (3) it reproduces well-regarded behavioural phenotypes associated with schizophrenia (e.g. MK- 801 induced hyperlocomotion); and (4) it implicates a disturbance in dopamine signaling. In summary, low prenatal levels of vitamin D can influence critical components of orderly brain development and that this has a long lasting effect on behaviour.
Resumo:
This paper is a foreword to a series of papers commissioned on 'the impact of science on the beef industry', where the Beef CRC-related collaborative scientific work of Professor Bernard Michael Bindon will be reviewed. These papers will be presented in March 2006, as part of a 'festschrift' to recognise his wider contributions to the Australian livestock industries for over 40 years. Bindon's career involved basic and applied research in many areas of reproductive physiology, genetics, immunology, nutrition, meat science and more recently genomics, in both sheep and cattle. Together with his collaborators, he made large contributions to animal science by improving the knowledge of mechanisms regulating reproductive functions and in elucidating the physiology and genetics of high fecundity livestock. His collaborative studies with many colleagues of the reproductive biology and genetics of the Booroola Merino were amongst the most extensive ever conducted on domestic livestock. He was instrumental in the development of immunological techniques to control ovulation rate and in examining the application of these and other techniques to increase beef cattle reproductive output. This paper tracks his investigations and achievements both within Australia and internationally. In the later stages of his career he was the major influence in attracting a large investment in Cooperative Research Centres for the Australian cattle industry, in which he directed a multi-disciplinary approach to investigate, develop and disseminate science and technology to improve commercial cattle productivity.
Resumo:
This paper reports the isolation of two putative D2R promoters from grey mullet, one 5' flanking and the other an intronic sequence immediately upstream of the first coding exon. Promoter activity of the intronic sequence was confirmed in vitro through functional analysis using luciferase as reporter gene. The functional characteristics of the region flanking the 5'-UTR is currently under investigation.
Resumo:
The current study aims to ascertain the fate of the melanocyte stimulating hormone (MSH) receptor and its ligand [Nle(4), D-Phe(7)]alpha-MsH (NDP-MSH) following binding to murine B16 melanoma cells. Cells were incubated with [I-125]-NDP-MSH for up to 180 min and binding, internalization and degradation determined. Intracellular trafficking of the radiolabel was assessed !using Percoll density gradient centrifugation of homogenized cells. Receptor down-regulation and receptor mRNA levels were also measured over 96 hr after exposure to 1 mu M ligand. NDP-MSH accumulation increased with time in a temperature-dependent manner and was inhibited by excess peptide. The ligand was rapidly internalized and translocated to the lysosomal compartment where it was degraded. Internalization was accompanied by a loss or down-regulation of cell surface receptors, suggesting internalization of the NDP-MSH-receptor complex. No recycling of the receptors between the plasma membrane and intracellular compartments could be detected in this cell-hue. Approximately 15% of the surface receptors were resistant to down-regulation, possibly indicating receptor heterogeneity. Down-regulation persisted ibr up to 96 hr and was accompanied by a decrease in MSH receptor mRNA levels 48 hr after treatment. However, before this time, transcript levels were the same in treated and control cells. In contrast to what was seen with NDP-MSH, cell surface receptors removed with trypsin wc:re rapidly replaced. These results show that NDP-MSH not only induced MSH receptor :internalization but also inhibited receptor turnover, resulting in a prolonged down-regulation. It is concluded that, in B16 cells, the MSH receptor undergoes ligand-dependent internalization, resulting in a prolonged down-regulation. Copyright (C) 1996 Elsevier Science Ltd
Resumo:
Necessary conditions on n, m and d are given for the existence of an edge-disjoint decomposition of K-n\K-m into copies of the graph of a d-dimensional cube. Sufficiency is shown when d = 3 and, in some cases, when d = 2(t). We settle the problem of embedding 3-cube decompositions of K-m into 3-cube decompositions of K-n; where n greater than or equal to m.
Genus II. Blastomonas. Sly and Cahill 1997, 567VP emend. Hiraishi, Kuraishi and Kawahara 2000a. 1117