Variable Length Optical Packet Synchronizer

Synchronization of asynchronously arriving variable length Internet Protocol packets to a local clock is demonstrated using a fiber-based optical synchronizer. The synchronizer is a four-stage feed-forward design with a resolution of 853 ps and a dynamic tuning range of 12.8 ns. The arrival time of packets is determined on a per packet basis using a payload envelope detection technique. The synchronizer state is dynamically configured on a per packet basis determined from the arrival time. Layer-1 (bit-error-rate) measurements are presented with power penalties 0.5 dB and an input power dynamic range 15 dB. Layer-2 (packet recovery) measurements are presented with power penalties 1.5 dB.     

Guidelines for the safe use of wastewater in agriculture: revisiting WHO guidelines.

The use of wastewater in agriculture is occurring more frequently because of water scarcity and population growth. Often the poorest households rely on this resource for their livelihood and food security needs. However, there are negative health implications of this practice that need to be addressed. WHO developed Guidelines for the Safe Use of Wastewater in Agriculture in 1989. The Guidelines are currently being revised based on new data from epidemiological studies, quantitative microbial risk assessments and other relevant information. WHO guidelines must be practical and offer feasible risk management solutions that will minimize health threats and allow for the beneficial use of scarce resources. To achieve the greatest impact on health, guidelines should be implemented with other health measures such as: health education, hygiene promotion, provision of adequate drinking water and sanitation, and other health care measures.     

Assessing user interfaces for diverse user groups: evaluation strategies and defining characteristics

User interface designers are challenged to design for diverse users, including those of different genders, cultures and abilities; however, little research has been directed at this problem. One factor which may inhibit such research is its cost. This paper presents an approach which offers a way to seek out important characteristics of designs in a cost-effective way and reports on the results. In a study reported here, subjects from different nationalities and of both genders evaluated three dialog boxes specifically designed for 'white American women'. 'European adult male intellectuals', and 'English-speaking-internationals'. The dialog boxes were evaluated with conjoint techniques of preference rankings, and factor-analysed adjective ratings. These results showed that female subjects had stronger and more consistent patterns of preferences than the male subjects. All subjects preferred interfaces rated high on an accessibility factor and disliked complex layouts; this effect was even stronger for women. Nationality did not effect ratings. Gender had a stronger effect on the outcome than nationality.     

Social support and prognosis in patients at increased psychosocial risk recovering from myocardial infarction.

Objective: To compare the impact of network support and different types of perceived functional support on all-cause mortality or nonfatal reinfarction for patients with a recent acute myocardial infarction (AMI). Design: Participants were recruited from the Enhancing Recovery in Coronary Heart Disease (ENRICHD) trial; 2,481 AMI patients with depression or low social support were randomized to a cognitive-behavioral intervention or to a usual care control group. Data collection for certain measures of social support was limited: 2,466 participants completed the ENRICHD Social Support Inventory; 2,457 completed the Perceived Social Support Scale; 1,296 completed the Social Network Questionnaire; and 707 completed the Interpersonal Support and Evaluation List, Tangible Support subscale. Patients also completed the Beck Depression Inventory and were followed for up to 4.5 years. Main Outcome Measure: Time to death or nonfatal reinfarction. Results: Over the follow-up period, 599 patients (24%) died or had a nonfatal AMI. Survival models controlling age, sex, race, socioeconomic status, smoking, antidepressant use, and a composite measure of increased risk revealed that higher levels of perceived social support were associated with improved outcome for patients without elevated depression but not for patients with high levels of depression. Neither perceived tangible support nor network support were associated with more frequent adverse events. Conclusion: AMI patients should be assessed for multiple dimensions of perceived functional support and depression to identify those at increased psychosocial risk who may benefit from treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biobehavioral approaches to the treatment of essential hypertension.

Despite recent advances in the medical management of hypertension, chronically elevated blood pressure remains a major health problem in the United States, affecting almost 50 million Americans. It is widely recognized that lifestyle factors contribute to the development and maintenance of elevated blood pressure. This article critically reviews current approaches to the nonpharmacological treatment of high blood pressure and highlights outcome studies of exercise, weight loss and dietary modification, and stress management and relaxation therapies. Methodological issues in the assessment and treatment of hypertension are discussed, along with possible mechanisms by which lifestyle modification may reduce elevated blood pressure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Delocalized carbanions: synthesis and polymerization of 2,3-disubstituted-1,3-butadienes

Summary The 2,3-dimethylene-1,3-butadiene dianion (2) was prepared from 2,3-dimethyl-1,3-butadiene (1) using Lochmann's base (n-BuLi/potassium-t-butoxide in pentane). The dianion was reacted with primary halides to yield 2,3-disubstituted-1,3-butadiene monomers. These monomers were polymerized free radically with AIBN and with Ziegler/Natta coordination catalysts. The resulting polymers were examined by DSC for crystallization of the polymer backbone and alkyl side chains.     

Directional coupler wavelength filters based on waveguides exhibiting electromagnetically induced transparency

We describe the principle and analyze the operation of an integrated optics directional coupler filter based on coupling between a regular waveguide and one that exhibits electromagnetically induced transparency. Bandwidth length products on the order of 2 pm /spl times/ mm are obtainable, as an example, using this approach.