Forward-scatter radiant mapping

Forward-scatter systems have been much neglected for the study of meteors and meteor streams. A great deal of this neglect stems from the complicated geometry which has made the interpretation of results difficult in the past. This no longer presents a problem because of the computer power now available. There are practical advantages in using forward-scatter in that low-power transmitters are much easier to handle than the high-power ones used in pulsed back-scatter radars. The data reduction of the CW signals is also significantly simpler. Because the forward-scatter reflection geometry increases the duration of the echoes relative to the back-scatter case, the problem of the underdense ceiling is partially alleviated. We have built a 'short hop' forward-scatter system between Ottawa and London (Ont) for which the transmitter and receiver are separated by about 500 km. With it, we are able to measure unambiguously the directions of arrival of the echoes using a 5-antenna interferometer. Morton and Jones (1982, MN, 198, 737) have shown how the echo direction distribution can be deconvolved to yield the meteor radiant distribution for back-scatter data. We have extended the technique to the forward-scatter case and present some preliminary meteor radiant distribution maps

Quasar-galaxy associations

There is controversy about the measurement of statistical associations between bright quasars and faint, presumably foreground galaxies. We look at the distribution of galaxies around an unbiased sample of 63 bright, moderate redshift quasars using a new statistic based on the separation of the quasar and its nearest neighbour galaxy. We find a significant excess of close neighbours at separations less than about 10 arcsec which we attribute to the magnification by gravitational lensing of quasars which would otherwise be too faint to be included in our sample. About one quarter to one third of the quasars are so affected although the allowed error in this fraction is large.Comment: uuencoded Postscript file (including figures and tables), SUSSEX-AST 94/8-

The potential and value of epidemiology in curbing non-communicable diseases.

Non-communicable diseases (NCDs) have reached pandemic levels globally and pose a major threat to social and economic development worldwide. The discipline of epidemiology has done much to bring this issue to the forefront of global health. Epidemiological approaches have broadened our understanding of the impact of NCDs in widening socioeconomic disparities. Over a number of decades, this discipline has also contributed to the development of many preventive measures and treatments of known efficacy and safety. However, epidemiology also has a critical role to play in better translating these discoveries into practice, through the new science of implementation. As we strive to achieve the "25 by 25" goal of a 25% reduction in premature mortality from common NCDs by 2025, the discipline of epidemiology will need to continuously evolve to remain an essential tool for public health action

Abundant variation in microsatellites of the parasitic nematode Trichostrongylus tenuis and linkage to a tandem repeat

An understanding of how genes move between and within populations of parasitic nematodes is important in combating the evolution and spread of anthelmintic resistance. Much has been learned by studying mitochondrial DNA markers, but autosomal markers such as microsatellites have been applied to only a few nematode species, despite their many advantages for studying gene flow in eukaryotes. Here, we describe the isolation of 307 microsatellites from Trichostrongylus tenuis, an intestinal nematode of red grouse. High levels of variation were revealed at sixteen microsatellite loci (including three sex-lined loci) in 111 male T. tenuis nematodes collected from four hosts at a single grouse estate in Scotland (average He = 0.708; mean number of alleles = 12.2). A population genetic analysis detected no deviation from panmixia either between (F(ST) = 0.00) or within hosts (F(IS) = 0.015). We discuss the feasibility of developing microsatellites in parasitic nematodes and the problem of null alleles. We also describe a novel 146-bp repeat element, TteREP1, which is linked to two-thirds of the microsatellites sequenced and is associated with marker development failure. The sequence of TteREP1 is related to the TcREP-class of repeats found in several other trichostrongyloid species including Trichostrongylus colubriformis and Haemonchus contortus

Pragmatic Trials for Noncommunicable Diseases: Relieving Constraints

At the 65th World Health Assembly in 2012, all World Health Organization member states made a historic commitment to reduce premature deaths from noncommunicable diseases (NCDs, including cardiovascular diseases, diabetes, cancer, and chronic respiratory diseases) by 25% by 2025. Subsequently, the World Health Assembly in 2013 agreed to adopt a global monitoring framework that included nine ambitious global NCD targets for 2025 [1]. These targets address key risk factors including tobacco and alcohol use, physical inactivity, high salt intake, high blood pressure, diabetes, and obesity and also the availability of basic technologies and medicines for the prevention and treatment of major NCDs

Pragmatic Trials for Noncommunicable Diseases: Relieving Constraints.

In this month's editorial, PLOS Medicine Editorial Board member Anushka Patel and Ruth Webster discuss how applying rules for drug efficacy trials can impede pragmatic trials of interventions for noncommunicable diseases

The potential and value of epidemiology in curbing non-communicable diseases

Non-communicable diseases (NCDs) have reached pandemic levels globally and pose a major threat to social and economic development worldwide. The discipline of epidemiology has done much to bring this issue to the forefront of global health. Epidemiological approaches have broadened our understanding of the impact of NCDs in widening socioeconomic disparities. Over a number of decades, this discipline has also contributed to the development of many preventive measures and treatments of known efficacy and safety. However, epidemiology also has a critical role to play in better translating these discoveries into practice, through the new science of implementation. As we strive to achieve the “25 by 25” goal of a 25% reduction in premature mortality from common NCDs by 2025, the discipline of epidemiology will need to continuously evolve to remain an essential tool for public health action