Long-term decline in krill stock and increase in salps within the Southern Ocean

Antarctic krill (Euphausia superba) and salps (mainly Salpa thompsoni) are major grazers in the Southern Ocean, and krill support commercial fisheries. Their density distributions have been described in the period 1926-51, while recent localized studies suggest short-term changes. To examine spatial and temporal changes over larger scales, we have combined all available scientific net sampling data from 1926 to 2003. This database shows that the productive southwest Atlantic sector contains >50% of Southern Ocean krill stocks, but here their density has declined since the 1970s. Spatially, within their habitat, summer krill density correlates positively with chlorophyll concentrations. Temporally, within the southwest Atlantic, summer krill densities correlate positively with sea-ice extent the previous winter. Summer food and the extent of winter sea ice are thus key factors in the high krill densities observed in the southwest Atlantic Ocean. Krill need the summer phytoplankton blooms of this sector, where winters of extensive sea ice mean plentiful winter food from ice algae, promoting larval recruitment and replenishing the stock. Salps, by contrast, occupy the extensive lower-productivity regions of the Southern Ocean and tolerate warmer water than krill. As krill densities decreased last century, salps appear to have increased in the southern part of their range. These changes have had profound effects within the Southern Ocean food web.     

The effects of vitamin E-deficiency on serum prolactin and serum luteinising hormone levels in the pregnant rat

Summary No significant differences were observed between the serum prolactin or serum LH levels of vitamin E-deficient or vitamin E-replete rats during the first 12 days of gestation. It is suggested that pituitary dysfunction is not the cause of the characteristic foetal resorption observed in vitamin E-deficient rats.Acknowledgments. The authors would like to thank Dr A.F. Parlow of the NIAMDD Rat Pituitary Hormone Distribution Programme for the generous supply of kits for the measurement of rat prolactin and LH, and Dr K.M.L. Morris (City of London Polytechnic) for arranging facilities for the radioiodination of the purified hormones used in the radioimmunoassays.     

Intermediate health care in a British inner city: An exercise in multiprofessional systems design

Health care in England is divided into the acute- and primary-care sectors. In the inner city the primary-care sector suffers from a number of ills that would be relieved by the introduction of a form of health care intermediate to it and the acute sector. This paper illustrates how members of the Department of General Practice at the University of Liverpool set about exploring the problems of the inner city and its health-care provision, as a means of arriving at a preliminary design for an intermediate-care service provision. The design was to form the basis for negotiations with other interested parties over the introduction of intermediate care in the inner city. The approach adopted was based on the soft systems methodology of P. B. Checkland. However, a number of variations on the traditional soft systems methodology were introduced, not the least of which was the introduction of new systemic metaphor into the root definition and conceptual modeling stages.     

The gene responsible for familial hypocalciuric hypercalcemia maps to chromosome 3q in four unrelated families.

Familial hypocalciuric hypercalcemia (FHH) is an autosomal dominant syndrome of unknown aetiology characterized by lifelong elevation in serum calcium concentration and low urinary calcium excretion. These features suggest that the causal gene is important for maintenance of extracellular calcium homeostasis by the parathyroid gland and kidney. To identify the chromosomal location of FHH gene(s), we clinically evaluated 114 individuals in four unrelated affected families and performed linkage analyses. The disease gene mapped to the long arm of chromosome 3 in each family (combined maximum multipoint lod score = 20.67). We suggest that this is the predominant FHH locus and anticipate that identification of the FHH gene will improve our understanding of the molecular basis for physiologic and pathologic regulation of calcium.     

Probability without certainty: foundationalism and the Lewis–Reichenbach debate

Like many discussions on the pros and cons of epistemic foundationalism, the debate between C. I. Lewis and H. Reichenbach dealt with three concerns: the existence of basic beliefs, their nature, and the way in which beliefs are related. In this paper we concentrate on the third matter, especially on Lewis’s assertion that a probability relation must depend on something that is certain, and Reichenbach’s claim that certainty is never needed. We note that Lewis’s assertion is prima facie ambiguous, but argue that this ambiguity is only apparent if probability theory is viewed within a modal logic. Although there are empirical situations where Reichenbach is right, and others where Lewis’s reasoning seems to be more appropriate, it will become clear that Reichenbach’s stance is the generic one. We conclude that this constitutes a threat to epistemic foundationalism.     

Changes in the plasma membrane surface of lymphocytes stimulated in vivo with DNCB.

Stereological principles have been used to evaluate ultrastructural changes which accompany the transformation of lymphocytes stimulated in vivo with dinitrochlorobenzene (DNCB). Whereas unstimulated lymphocytes and blast cells have slightly more than the minimal containing plasmalemmal surface for their volume, stimulated (blast-derived) lymphocytes have an excess surface area in the order of 30%. This observation is discussed in the context of altered cell function and the biosynthesis of additional membrane components.     

Changes in the plasma membrane surface of lymphocytes stimulated in vivo with DNCB

Summary Stereological principles have been used to evaluate ultrastructural changes which accompany the transformation of lymphocytes stimulated in vivo with dinitrochlorobenzene (DNCB). Whereas unstimulated lymphocytes and blast cells have slightly more than the minimal containing plasmalemmal surface for their volume, stimulated (blast-derived) lymphocytes have an excess surface area in the order of 30%. This observation is discussed in the context of altered cell function and the biosynthesis of additional membrane components.We wish to thank Prof. R. Barer for his continued support and encouragement. The work was undertaken by M.M. A.-H. in part fulfilment of requirements for the degree of Ph. D. in this department. M.M. A-H. was supported by the Ministry of Higher Education and Scientific Research, Government of Iraq.     

Large-scale genetic fine mapping and genotype-phenotype associations implicate polymorphism in the IL2RA region in type 1 diabetes

Genome-wide association studies are now identifying disease-associated chromosome regions. However, even after convincing replication, the localization of the causal variant(s) requires comprehensive resequencing, extensive genotyping and statistical analyses in large sample sets leading to targeted functional studies. Here, we have localized the type 1 diabetes (T1D) association in the interleukin 2 receptor alpha (IL2RA) gene region to two independent groups of SNPs, spanning overlapping regions of 14 and 40 kb, encompassing IL2RA intron 1 and the 5' regions of IL2RA and RBM17 (odds ratio = 2.04, 95% confidence interval = 1.70-2.45; P = 1.92 x 10(-28); control frequency = 0.635). Furthermore, we have associated IL2RA T1D susceptibility genotypes with lower circulating levels of the biomarker, soluble IL-2RA (P = 6.28 x 10(-28)), suggesting that an inherited lower immune responsiveness predisposes to T1D.     

铁及低碳钢的超快速退火

通过电阻加热方法实现了加热速度为 1 000—5 000℃/s,由此使铁及低碳钢的再结晶温度由 650℃降为 610℃,这一新型的热处理方法——超快速退火法(Ultra-rapid annealing),可以在不到一秒钟的时间内有效地软化材料,使其具有良好的机械性能,而且再结晶机理也要发生变化。在加热速度 1 000 ℃/s以上,回复效应随加热速率的提高而降低。本文重点研究了脱碳、脱氮钢,用超快速退火处理后,材料的最低硬度一般在 87.2 HV2.5kg。