The challenges of disconnected delay-tolerant MANETs

This article is concerned with the challenges associated with supporting communication in disconnected MANETs with such a sparse population of nodes and so little (or no) fixed infrastructure that the network graph is rarely, if ever, connected. The networks considered are autonomous and do not depend on established infrastructure. The disconnected nature and the lack of end-to-end connectivity between nodes mean that the communication must be delay-tolerant. We refer to such a networks as Disconnected Delay-Tolerant MANETs (DDTMs). In general the challenges associated with mobile computing are not new. However, issues in wireless communication such as low bandwidth, disconnections and high bandwidth variability are problematic and further exacerbated in DDTMs by little or no infrastructure, variable node population and lossy links. DDTMs additionally face challenges of mobility which is frequent and uncontrolled resulting in a highly dynamic topology and disconnected network graph. In addition, portability remains a challenge, where battery power, memory and processing power are limited. The challenges are presented using a two-tier classification scheme that allows their causes and inter-dependencies to be mapped.     

Modelling the heart as a communication system

Electrical communication between cardiomyocytes can be perturbed during arrhythmia, but these perturbations are not captured by conventional electrocardiographic metrics. We developed a theoretical framework to quantify electrical communication using information theory metrics in two-dimensional cell lattice models of cardiac excitation propagation. The time series generated by each cell was coarse-grained to 1 when excited or 0 when resting. The Shannon entropy for each cell was calculated from the time series during four clinically important heart rhythms: normal heartbeat, anatomical reentry, spiral reentry and multiple reentry. We also used mutual information to perform spatial profiling of communication during these cardiac arrhythmias. We found that information sharing between cells was spatially heterogeneous. In addition, cardiac arrhythmia significantly impacted information sharing within the heart. Entropy localized the path of the drifting core of spiral reentry, which could be an optimal target of therapeutic ablation. We conclude that information theory metrics can quantitatively assess electrical communication among cardiomyocytes. The traditional concept of the heart as a functional syncytium sharing electrical information cannot predict altered entropy and information sharing during complex arrhythmia. Information theory metrics may find clinical application in the identification of rhythm-specific treatments which are currently unmet by traditional electrocardiographic techniques.     

Spiritual issues in counseling: Clients' beliefs and preferences.

The current study assessed psychotherapy clients' beliefs about the appropriateness of discussing religious and spiritual concerns in counseling, clients' preferences for such discussion, and identified explanatory variables for these beliefs and preferences. These variables were assessed using the Client Attitudes toward Spirituality in Therapy survey; the Index of Spiritual Experiences (J. D. Kass, R. Friedman, J. Leserman, P. C. Zuttermeister, & H. Benson, 1991); the Expectations About Counseling-Brief Form (H. E. A. Tinsley, 1982); the Religious scale of the Counseling Appropriateness Check List (R. Warman, 1960); the Socially Desirable Response Set-5 Scale (R. D. Hays, T. Hayashi, & A. L. Stewart, 1989); and the Religion Section of the Mooney Problem Check List-Adult Form (L. V. Gordon & R. L. Mooney, 1950). Clients believed religious concerns were appropriate for discussion in counseling and had a preference for discussing spiritual and religious issues in counseling. Spiritual experience was the most potent variable for explaining preferences for discussing spiritual issues. Implications and limitations of the study are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Positron Annihilation Lifetime Spectra in a Metakaolin-Based Geopolymer

Significant nanoporosity as indicated by positron annihilation lifetime spectroscopy (PALS) has been observed in a metakaolin-based geopolymer. The nanoporosity was indicated by a component of the PALS spectrum having a lifetime of 1.5–2 ns, characterizing a pore diameter size of ∼0.5 nm. Progressive heating to 600°C decreased the intensity of this spectral component from ∼10% to 2.5%. Positron annihilation in free pore water appears to be only a minor contributor to this spectral component. The Barrett–Joyner–Halenda (BJH) method pore distribution data, derived from BET nitrogen adsorption isotherms, showed the presence of considerable meso- and macroporosity in the samples. However, these porosities were not evident in the PALS spectrum. Heating from 150° to 600°C progressively changed the smallest detectable pore size via the BJH method from 3.3 to 7.1 nm.     

Release of antioxidants from co-extruded active packaging developed for whole milk powder

Control of oxidation is a basic criterion to maintain the quality of milk and dairy products. Multilayer co-extruded films are often used to limit the diffusion of oxygen from the environment into the package. In this study, multilayer co-extruded films made of high density polyethylene (added with titanium dioxide), ethylene vinyl alcohol and a layer of low density polyethylene containing the antioxidants butylated hydroxyanisole (1.5%), butylated hydroxytoluene (1.5%) and α-tocopherol (4%) were manufactured. The release of the antioxidants from the films to whole milk powder was determined during 30 days at 30 °C. Whole milk powder stability was measured by monitoring vitamin A, hexanal, pentanal and heptanal content. Butylated hydroxytoluene and butylated hydroxyanisole migrated quickly from the films to the milk powder, while α-tocopherol migrated gradually. Multilayer co-extruded films provided an adequate light-barrier for whole milk powder and the film added with α-tocopherol contributed to the protection of vitamin A degradation compared with the other films.     

Reliability and performance of a true enhancement mode HIGFET for wireless applications

Freescale’s true enhancement mode (EMODE) HIGFET is a high performance single supply technology used for wireless power amplifiers. It is the first technology of its kind to be produced in a high volume manufacturing environment. The EMODE HIGFET intrinsic reliability was evaluated using a conventional three temperature DC accelerated stress test. The device used for these tests has a total gate width of 0.6 mm, a gate length of 0.8 μm, and a die thickness of 3 mils. The device has no through-wafer vias, is representative of the unit cell for larger devices, and was processed using a production mask set.For targeted applications with a system life of 5 years, the first expected failure at 150 °C for the 1 ppm level was determined to be 82 years at a 90% lower confidence level, which exceeds the reliability requirements for subscriber unit power amplifiers by a wide margin. This work demonstrates that EMODE HIGFET devices are high performance RF devices with intrinsic reliability well in excess of anticipated system requirements.     

Does marriage and relationship education work? A meta-analytic study.

In this meta-analytic study, the authors examined the efficacy of marriage and relationship education (MRE) on 2 common outcomes: relationship quality and communication skills. A thorough search produced 86 codable reports that yielded 117 studies and more than 500 effect sizes. The effect sizes for relationship quality for experimental studies ranged from d = .30 to .36, while the communication skills effect sizes ranged from d = .43 to .45. Quasi-experimental studies generated smaller effect sizes, but these appeared to be due to pretest group differences. Moderate-dosage programs produced larger effect sizes than did low-dosage programs. For communication skills, published studies had larger effects than those of unpublished studies at follow-up; there were no publication differences for relationship quality. There was no evidence of a gender difference. Unfortunately, a lack of racial/ethnic and economic diversity in the samples prevented reliable conclusions about the effectiveness of MRE for disadvantaged couples, a crucial deficit in the body of research. In addition, intervention outcomes important to policy makers, such as relationship stability and aggression, rarely have been addressed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Using lexical familiarity judgments to assess verbally mediated intelligence in aphasia.

In this study, a task using forced-choice lexical familiarity judgments of irregular versus archaic words (a newly developed measure called the Lexical Orthographic Familiarity Test; LOFT) was compared to a standardized oral word-reading measure (the Wechsler Test of Adult Reading; WTAR) in a group of 35 aphasic adults and a comparison group of 125 community dwelling, nonbrain damaged adults. When compared to the comparison group, aphasics had significantly lower scores on the WTAR but not the LOFT. Although both the WTAR and LOFT were significantly correlated with education in the nonbrain-damaged group, only the LOFT was correlated with education and also with the Barona full scale IQ index in the aphasic group. Lastly, WTAR performance showed a significantly greater relationship to the severity of language disorder in the aphasic group than did the LOFT. These results have both theoretical and clinical implications for the assessment of language-disordered adults, as they indicate that patients with aphasia may retain aspects of verbally mediated intelligence, and that the LOFT may provide a better estimate of premorbid functioning in aphasia than other currently available measures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In Situ Rheo-NMR Measurements of Solid Fat Content

The properties of crystallized fats depend on their solid fat content (SFC) and their fractal structures. The SFC and the structures are dramatically affected during crystallization under shear flow. A mini-Couette cell was developed to crystallize fat samples under shear. The cell was tested with blends of canola stearin (CS) in canola oil (CO) in a 20-MHz NMR spectrometer. The blends were placed in the cell, melted at 80 °C, and then crystallized under different shear rates (58–460 s⁻¹) at 40 °C inside the spectrometer for 4 h. Time averaged NMR free induction decay (FID) curves were captured at 20 s intervals. SFC values were calculated using parameters determined by a calibration procedure. The SFC values determined by the direct method with and without the shaft of the Couette device were reasonably close. Similar results were observed with and without shear in the Couette device. The FID curves did not show a significant difference either. Therefore this system is accurate for in-situ time-resolved determination of SFC under shear flow. Furthermore, a combination of the direct and the indirect methods was successfully used to estimate the temperature increase due to viscous heating. The system developed will help in understanding the effects of shear flow on SFC of nanostructured lipid multicomponent systems. This will permit the optimization of the manufacturing processes.