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Selected Abstracts

Design and analysis of a scalable algorithm to monitor chord-based p2p systems at runtime

Andreas Binzenhöfer
Abstract Peer-to-peer (p2p) systems are a highly decentralized, fault tolerant, and cost-effective alternative to the classic client,server architecture. Yet companies hesitate to use p2p algorithms to build new applications. Due to the decentralized nature of such a p2p system the carrier does not know anything about the current size, performance, and stability of its application. In this paper, we present an entirely distributed and scalable algorithm to monitor a running p2p network. The snapshot of the system enables a telecommunication carrier to gather information about the current performance parameters of the running system as well as to react to discovered errors. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Measuring metabolic rate in the field: the pros and cons of the doubly labelled water and heart rate methods

P. J. Butler
Summary 1Measuring the metabolic rate of animals in the field (FMR) is central to the work of ecologists in many disciplines. In this article we discuss the pros and cons of the two most commonly used methods for measuring FMR. 2Both methods are constantly under development, but at the present time can only accurately be used to estimate the mean rate of energy expenditure of groups of animals. The doubly labelled water method (DLW) uses stable isotopes of hydrogen and oxygen to trace the flow of water and carbon dioxide through the body over time. From these data, it is possible to derive a single estimate of the rate of oxygen consumption () for the duration of the experiment. The duration of the experiment will depend on the rate of flow of isotopes of oxygen and hydrogen through the body, which in turn depends on the animal's size, ranging from 24 h for small vertebrates to up to 28 days in Humans. 3This technique has been used widely, partly as a result of its relative simplicity and potential low cost, though there is some uncertainty over the determination of the standard error of the estimate of mean . 4The heart rate (fH) method depends on the physiological relationship between heart rate and . 5If these two quantities are calibrated against each other under controlled conditions, fH can then be measured in free-ranging animals and used to estimate . 6The latest generation of small implantable data loggers means that it is possible to measure fH for over a year on a very fine temporal scale, though the current size of the data loggers limits the size of experimental animals to around 1 kg. However, externally mounted radio-transmitters are now sufficiently small to be used with animals of less than 40 g body mass. This technique is gaining in popularity owing to its high accuracy and versatility, though the logistic constraint of performing calibrations can make its use a relatively extended process. [source]

Lobular panniculitis at the site of glatiramer acetate injections for the treatment of relapsing-remitting multiple sclerosis.

A report of two cases
Lipoatrophy and localized panniculitis have been described as rare complications of daily subcutaneous glatiramer acetate injections for the treatment of relapsing-remitting multiple sclerosis (MS). We describe the biopsies from two MS patients in a single neurologist's practice who developed clinical lesions of lipoatrophy at the sites of subcutaneous glatiramer acetate injections. These biopsies showed a lobular panniculitis with lipoatrophy that more closely resembled lupus panniculitis than previous reports of localized panniculitis at glatiramer acetate injection sites. In one case, the area of clinical lipoatrophy continued to enlarge for 6 months after stopping glatiramer acetate therapy, before stabilizing at its current size for the last 8 months. Injection site reactions to glatiramer acetate should be considered in the differential diagnosis of biopsies that show a lupus panniculitis-like appearance. Our observations indicate that glatiramer acetate induced panniculitis is common and may continue to progress after therapy has stopped. In this single neurologist's practice, 64% of the patients receiving daily glatiramer acetate injections had clinical evidence of lipoatrophy or panniculitis. Of 100 consecutive patients receiving therapy for MS between February and November 2006, 14 patients were on glatiramer acetate, 9 of whom had clinical lipoatrophy. [source]

Cholesterol metabolism in 8 to 12-year-old children born preterm or at term

M Mortaz
Studies in animals have indicated that cholesterol metabolism is susceptible to manipulation by diet and growth in early life. In humans, low birthweight has been associated with increased risk of coronary heart disease. Aim: To establish whether plasma lipids and indicators of cholesterol absorption, synthesis and breakdown differ in children born preterm and at term. Methods: Plasma total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol, triacylglycerols, apolipoprotein A1, apolipoprotein B, lathosterol (indicator of cholesterol synthesis), campesterol (indicator of cholesterol absorption), 7-, hydroxycholesterol (indicator of cholesterol breakdown) were measured in up to 407 children born preterm and 36 children born at term. Results: Children born preterm had lower cholesterol synthesis (p= 0.002) and lower cholesterol breakdown (p < 0.001) than those born at term, but their plasma cholesterol concentration was not significantly different. After adjusting for current size, birthweight and gestational age were significantly related to plasma lathosterol and 7-, hydroxycholesterol. However, when both birthweight and gestational age were adjusted, only gestational age remained significant. There were no significant differences in plasma campesterol between the two groups. Conclusion: Being born preterm may have a long-term effect on cholesterol metabolism in children 8,12 y later. Those born prematurely had lower cholesterol synthesis and breakdown, but their plasma cholesterol concentration was similar at this age. These parameters need to be studied in older cohorts. [source]