Fibre backbone for cable TV using multi-channel am video trunking

This paper updates a scenario for the evolutionary integration of optical fibre transmission technology into existing cable television networks first presented in 1988. The resulting ‘fibre backbone’ yields a hybrid fibre/coaxial network with significantly better reliability and transmission quality than present systems. System and electro-optical component advances in the last year are reviewed, and the merits of various modulation techniques are examined. The fibre backbone approach emphasizes continuing the broadband delivery of a large number of video signals to the consumer.     

Shallow Linear Action Graphs and their Embeddings

Action calculi, which generalise process calculi such as Petri nets, π-calculusand ambient calculus, have been presented in terms of action graphs. We here offer linear action graphs as a primitive basis for action calculi. This paper presents the category of embeddings of undirected linear action graphs without nesting, using a novel form of graphical reasoning which simplifies some otherwise complex manipulations in regular algebra. The results are adapted in a few lines to directed graphs. This work is part of a long-term search for a uniform behavioural theory for process calculi. Received October 2000 / Accepted in revised form April 2001     

Effect of moderate to very low fat defined formula diets on serum lipids in healthy subjects

Serum total cholesterol, high density lipoprotein (HDL) cholesterol, and triglyceride levels were studied in healthy male and female subjects consuming for one-week periods a diet of conventional food (CF) providing 42% of energy as fat, principally butter fat, and then in random order nutritionally complete, defined formula diets of moderate (32%) to very low (1%) fat content. Compared to CF, the formula with 32% of energy as corn oil lowered serum cholesterol by 25% and the ratio of total to HDL-cholesterol by 13%. Low (9%) and very low (1–3%) fat formulas reduced HDL-cholesterol by as much as 40%, raised the total: HDL-cholesterol ratio by about 20% and raised serum triglyceride levels by as much as 100%. When low and very low fat formulas were ingested for three weeks, these effects persisted although maximal responses occurred during the first week. These results demonstrated that a moderate fat formula diet with a high P/S ratio had a more favorable effect on serum lipid levels than various low fat formulas. Low fat conventional food diets should be studied in long-term controlled metabolic experiments before such diets are recommended to the general population for coronary heart disease or cancer prevention.     

Improving signal prediction performance of neural networks through multiresolution learning approach.

In this paper, we extend the original work on multiresolution learning for neural networks, and present new developments on the multiresolution learning paradigm. The contributions of this paper include: (1) proposing a new concept and method of adjustable neural activation functions in multiresolution learning to improve neural network learning efficacy and generalization performance for signal predictions; (2) providing new insightful explanations for the multiresolution learning paradigm from a multiresolution optimization perspective; (3) exploring underlying ideas why the multiresolution learning scheme associated with adjustable activation functions would be more appropriate for the multiresolution learning paradigm; and (4) providing rigorous validations to evaluate the multiresolution learning paradigm with adjustable activation functions and comparing it with the schemes of multiresolution learning with fixed activation functions and traditional learning. This paper presents systematically new analytical and experimental results on the multiresolution learning approach for training an individual neural network model, demonstrates our integral solution on neural network learning efficacy, and illustrates the significant improvements on neural networks' generalization performance and robustness for nonlinear signal predictions.     

Advances in the stabilization of flexible PVC by using a liquid calcium‐zinc technology

The global market for liquid mixed‐metal stabilizers is migrating toward heavy‐metal‐free products, Historically, these systems have not been performance and cost competitive. High efficiency calcium‐zinc stabilizers have the potential to replace heavy‐metal‐based products. The intrinsic value of non‐phenolic lubricating calcium intermediates and calcium‐zinc stabilizers is discussed.     

Using bald eagles to indicate the health of the Great Lakes' environment

The bald eagle (Haliaeetus leucocephalus) is one of the most studied birds of North America, and a great amount of natural life‐history information, including the response of various stressors on the eagles' ability to reproduce, are well known. In Michigan, the eagle has been chosen to track the trends of bioaccumulative compounds of concern across watersheds in the state. The state has been divided into major watersheds, and 20% of these are surveyed each year. A control area in northern Minnesota, Voyageurs National Park, is also sampled annually. We report here on the methods used, the preliminary results of the 1999 field season, and how differences in mercury concentrations varied over a 10‐year period. Mercury in feathers of nestling eagles declined over time only in Lakes Michigan and Huron, but have not decreased among other subpopulations in Michigan. Concentrations of polychlorinated biphenyls (PCBs) and 4,4′‐DDE in blood plasma from nestling eagles have declined over time for most subpopulations; however, they remain greater for breeding areas associated with the Great Lakes' food web. Sea eagles of the genus Haliaeetus are a good sentinel species to track trends in bioaccumulative compounds in aquatic systems.     

熔融-固相缩聚法中固相聚合对聚乳酸合成的影响

以L 乳酸单体为原料 ,熔融 -固相缩聚法合成了聚乳酸 ,重点研究了固相聚合的工艺条件。结果表明 ,绝对压力 60Pa ,氯化亚锡为催化剂 ,分段控温 ,可使聚乳酸的粘均分子量提高到固相聚合反应前的 5 3倍。通过对固相聚合产物的结晶度和熔点的分析 ,探讨了固相聚合的机理。     

AN ASSESSMENT OF CRACK CLOSURE AND THE EXTENT OF THE SHORT CRACK REGIME IN Q1N (HY80) STEEL

Abstract— The paper addresses some aspects of the differences in fatigue crack growth rate behaviour and threshold values obtained for long through-cracks, short through-cracks and surface cracks. Attention is focused on plasticity induced closure in the wake behind the growing crack tip. For long cracks at high K _max, closure is found to depend in a linear manner on K _max, i.e. K _op, increases with the size of the monotonic plastic zone. Closure increases at low δ K and this is primarily a consequence of the load shedding procedure. If short through-cracks are prepared by machining specimens containing long cracks, a substantial part of the plastic wake is removed and this can produce marked effects on the closure contribution during subsequent growth. The length of crack "closed" in a long crack threshold test was found to be of the order of 1 mm. Cracks less than this length exhibited "short crack" behaviour: greater than this length, they behaved as "long cracks", with plastic wake effects apparently fully operative. Small surface cracks exhibit "long crack" behaviour at lengths as short as 0.2 mm and reasons for this are discussed.     

Single-longitudinal-mode fiber ring laser employing an equivalent phase-shifted fiber Bragg grating

A novel single-longitudinal-mode (SLM) fiber ring laser that incorporates an equivalent phase-shifted fiber Bragg grating acting as an ultra-narrow bandpass filter in the laser cavity is proposed. The equivalent phase-shifted fiber Bragg grating has an ultra-narrow transmission bandwidth which ensures an SLM lasing. Stable SLM operation without mode hopping is demonstrated.