SOAR: Simple Opportunistic Adaptive Routing Protocol for Wireless Mesh Networks

Multihop wireless mesh networks are becoming a new attractive communication paradigm owing to their low cost and ease of deployment. Routing protocols are critical to the performance and reliability of wireless mesh networks. Traditional routing protocols send traffic along predetermined paths and face difficulties in coping with unreliable and unpredictable wireless medium. In this paper, we propose a Simple Opportunistic Adaptive Routing protocol (SOAR) to explicitly support multiple simultaneous flows in wireless mesh networks. SOAR incorporates the following four major components to achieve high throughput and fairness: 1) adaptive forwarding path selection to leverage path diversity while minimizing duplicate transmissions, 2) priority timer-based forwarding to let only the best forwarding node forward the packet, 3) local loss recovery to efficiently detect and retransmit lost packets, and 4) adaptive rate control to determine an appropriate sending rate according to the current network conditions. We implement SOAR in both NS-2 simulation and an 18-node wireless mesh testbed. Our extensive evaluation shows that SOAR significantly outperforms traditional routing and a seminal opportunistic routing protocol, ExOR, under a wide range of scenarios.     

The effects of patterned calorie-restricted diets on mammary tumor incidence and plasma endothelin levels in DMBA-treated rats

Chronic caloric restriction has been shown to inhibit mammary tumor promotion in the 7,12-dimethyl-benz[a]anthracene (DMBA) rat mammary tumor model. The objectives of this study were to determine (i) the effects of chronic caloric cycling (yo-yo dieting) on mammary tumor promotion by high fat diets and (ii) the effect of three dietary regimens +/- superimposed mammary tumor burden on plasma endothelin-1,2 (ET) levels. Female Sprague-Dawley rats were treated with DMBA (5 mg/rat) and divided into three dietary groups: ad libitum (AL) (containing 15% corn oil); 40% calorie restricted (CR) (containing 20% corn oil so consumption of fat was equivalent between AL and CR); a calorie cycled (CC) group fed alternatively AL and CR diets each 48 h period. After 10 weeks, tumor incidences were: AL, 63%; CR, 27%; CC, 57% (AL versus CR, P < 0.05; CC versus CR, P < 0.05; AL versus CC, NSD). ET levels (pg/ml plasma) were: AL, 16.0 +/- 6.54; CR, 32.31 +/- 0.34; CC, 23.44 +/- 5.04 (AL versus CR, P < 0.01; CC versus CR, P < 0.01; AL versus CC, P < 0.05). Plasma ET levels were independent of tumor incidence and tumor burden, but plasma ET levels were significantly increased in rats with a prior history of calorie restriction. As expected, maintained caloric restriction reduced mammary tumor incidence but intermittent caloric restriction (caloric cycling or yo-yo dieting) was without similar benefit.     

A prolonged QRS duration on surface electrocardiogram is a specific indicator of left ventricular dysfunction [see comment

OBJECTIVE: We sought to determine whether a prolonged QRS-interval duration is associated with decreased left ventricular (LV) systolic function. BACKGROUND: The 12-lead electrocardiogram (ECG) is a routine test for suspected cardiac disease. Although several scoring systems have been devised to estimate LV systolic function, no studies have examined the direct relationship between QRS duration alone and LV systolic function. METHODS: We analyzed the standard 12-lead surface ECG of 270 consecutive patients, referred for radionuclide ventriculography. Patients (n = 44) with bundle branch blocks, atrial flutter or fibrillation, pacemaker rhythm, recent myocardial infarction or bypass surgery, and patients on antiarrhythmic drugs were excluded. In the remaining patients (n = 226), we correlated the QRS duration on standard resting ECG, and the resting LV ejection fraction (EF), end-systolic and end-diastolic counts (ESC and EDC, respectively; LV volume indices), as obtained by radionuclide angiography. We used a multivariate analysis to identify independent predictors of reduced ventricular function entering QRS duration, the previously described R-wave score and clinical variables in our model. RESULTS: The QRS duration in the abnormal EF group was significantly longer than in the normal EF group (0.102 vs. 0.091 s, p < 0.0001). A QRS duration >0.10 s was highly specific (83.6%), but modestly sensitive (43.8%), for the prediction of abnormal EF. Furthermore, an abnormal EF was predicted with incrementally increased specificity (83.6% to 99.3%) and a corresponding decrease in sensitivity (43.8% to 13.8%) for each 0.01-s increase in the definition of prolonged QRS (from >0.10 to >0.12 s). Accordingly, the positive likelihood ratio for the prediction of decreased LV function was increased from 2.67 to 19.7 as the definition of prolonged QRS duration was increased from >0.10 to >0.12 s. In the multivariate analysis, a prolonged QRS duration and a low R-wave score were the only independent predictors of decreased LV systolic function. CONCLUSIONS: Prolonged QRS duration (>0.10 s) obtained from a standard resting 12-lead ECG is a specific, but relatively insensitive indicator of decreased LV systolic function. Further prolongation of the QRS had a higher specificity for decreased LV EF and a higher positive likelihood ratio for predicting abnormal LV EF.     

Quality,functionality, and shelf life of fermented meat and meat products: A review

Fermentation of meat is a traditional preservation method used widely for improving quality and shelf life of fermented meat products. Fermentation of meat causes a number of physical, biochemical, and microbial changes, which eventually impart functional properties, sensory characteristics, and nutritional aspects to these products and inhibit the growth of various pathogenic and spoilage microorganisms. These changes include acidification (carbohydrate catabolism), solubilization and gelation of myofibrillar and sarcoplasmic proteins of muscle, degradation of proteins and lipids, reduction of nitrate into nitrite, formation of nitrosomyoglobin, and dehydration. Dry-fermented sausages are increasingly being used as carrier of probiotics. The production of biogenic amines during fermentation can be controlled by selecting proper starter cultures and other preventive measures such as quality of raw materials, hygienic measures, temperature, etc.     

Spectral interferometric microscope with tandem liquid-crystal Fabry-Perot interferometers for extension of the dynamic range in three-dimensional step-height measurement

The maximum measurable range of a spectral interference microscope depends on the coherence length of the light transmitted by its tunable spectral filter. To achieve a large range in step-height measurement we have developed a new tunable spectral filter that uses tandem liquid-crystal Fabry-Perot interferometers (LC-FPIs), which can simultaneously attain both a high spectral resolution and a large tuning range. Fringe visibility measurements were carried out, and it was found that the coherence length of the light transmitted through tandem LC-FPIs is two times larger than that transmitted through a single LC-FPI. Using this novel tunable spectral filter, we developed a new spectral interference microscope for the measurement of three-dimensional shapes of discontinuous objects. Experimental results of step-height measurements both with a single LC-FPI and with tandem LC-FPIs are presented for a combination of standard steel gauge block sets with 1-, 99-, and 100-microm steps. A large range (1-100 microm) of measurement with submicrometer resolution was achieved with tandem LC-FPIs that was not possible with our previous system in which a single LC-FPI was used.     

Analytic Tangent Irradiance Environment Maps for Anisotropic Surfaces

Environment‐mapped rendering of Lambertian isotropic surfaces is common, and a popular technique is to use a quadratic spherical harmonic expansion. This compact irradiance map representation is widely adopted in interactive applications like video games. However, many materials are anisotropic, and shading is determined by the local tangent direction, rather than the surface normal. Even for visualization and illustration, it is increasingly common to define a tangent vector field, and use anisotropic shading. In this paper, we extend spherical harmonic irradiance maps to anisotropic surfaces, replacing Lambertian reflectance with the diffuse term of the popular Kajiya‐Kay model. We show that there is a direct analogy, with the surface normal replaced by the tangent. Our main contribution is an analytic formula for the diffuse Kajiya‐Kay BRDF in terms of spherical harmonics; this derivation is more complicated than for the standard diffuse lobe. We show that the terms decay even more rapidly than for Lambertian reflectance, going as l^–3, where l is the spherical harmonic order, and with only 6 terms (l = 0 and l = 2) capturing 99.8% of the energy. Existing code for irradiance environment maps can be trivially adapted for real‐time rendering with tangent irradiance maps. We also demonstrate an application to offline rendering of the diffuse component of fibers, using our formula as a control variate for Monte Carlo sampling.     

A Bluetooth Based Sensor Network for Civil Infrastructure Health Monitoring

Communicating with sensors has long been limited either to wired connections or to proprietary wireless communication protocols. Using a ubiquitous and inexpensive wireless communication technology to create Sensor Area Networks (SANs) will accelerate the extensive deployment of sensor technology. Bluetooth, an emerging, worldwide standard for inexpensive, local wireless communication is a viable choice for SANs because of its inherent support for some of the important requirements – low power, small form factor, low cost and sufficient communication range. In this paper we outline an approach, centered on the Bluetooth technology, to support a sensor network composed of fixed wireless sensors for health monitoring of highways, bridges and other civil infrastructures. We present a topology formation scheme that not only takes into account the traffic generated by different sensors but also the associated link strengths, buffer capacities and energy availability. The algorithm makes no particular assumptions as to the placement of nodes, and not all nodes need to be in radio proximity of each other. The output is a tree shaped scatternet rooted at the sensor hub (data logger) that is balanced in terms of traffic carried on each of the links. We also analyze the scheduling, routing and healing aspects of the resulting sensor-net topology.     

An evidence-based review of the effectiveness of cognitive behavioral therapy for psychosocial issues post-spinal cord injury.

Study Design: Systematic review. Objective: To examine the evidence supporting the effectiveness of cognitive behavioral therapy (CBT) for improving psychosocial outcomes in individuals with spinal cord injury (SCI). Method: Electronic databases (MEDLINE, CINAHL, EMBASE, and PsycINFO) were searched for studies published between 1990 and October 2010. Randomized control trials (RCTs) and nonrandomized control trials (non-RCTs) utilizing a CBT intervention to improve psychosocial outcomes (depressive symptomatology, anxiety, coping, and adjustment to disability) in outpatient persons with SCI were included for review. Levels of evidence were assigned to each study using a modified Sackett scale. Effect size calculations for the interventions were provided where possible. Results: Nine studies met the inclusion criteria. The studies reviewed included two RCTs, six prospective controlled trials (PCTs) and one cohort study. All studies examined at least two groups. There is Level 1 and Level 2 evidence supporting the use of specialized CBT protocols in persons with SCI for improving outcomes related to depression, anxiety, adjustment, and coping. Conclusions: CBT holds promise as an effective approach for persons with SCI experiencing depression, anxiety, adjustment, and coping problems. As CBT may involve many different components, it is important in the future to determine which of these elements alone or in combination is most effective in treating the emotional consequences of SCI. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Effect of chromium on the mechanical properties of powder-processed Fe–0.45 wt.% P alloys

The present investigation shows the role of chromium in Fe–P binary and Fe–P–Cr ternary alloys. The compositions are characterized in terms of microstructure, porosity content, hardness and tensile properties. The alloys were made using a hot powder forging technique. In this process mild steel encapsulated powders were hot forged into slabs. Then the slabs were hot rolled and annealed to relieve the residual stresses. Densifications as high as 98.9% of theoretical density have been realized. Microstructures of these alloys consist of single-phase ferrite only. Both Fe–0.45P and Fe–0.45P–3Cr alloys showed very high strength. As forged and hot rolled Fe–0.45P alloy showed low elongation. It was observed that, the addition of Cr to Fe–P based alloys caused an increase in strength associated with the reduction in ductility. Alloys developed in the present investigation were capable of hot working to very thin gage of sheets and wires.