Hybrid acrylic–polyimide latexes from miniemulsion polymerisation

A rigid polyimide (PI) was dissolved in acrylic monomers (methyl methacrylate, n‐butyl acrylate) as a hydrophobe to form miniemulsions stabilized by a mixture of sodium dodecyl sulfate and Triton^®, with droplets size in the range 100–300 nm, and PI concentration up to about 30% by weight, which corresponds to its limit of solubility. Upon polymerization initiated with ammonium persulfate, the particle size tends to decrease to the range 80–250 nm. From these hybrid latexes, clear yellowish films were obtained with two glass transitions: one close to that of polybutylacrylate (T_g = ?50 °C) and the second between 15 and 40 °C, depending on PI concentration. PI causes a reinforcement of the mechanical properties at room temperature. This reinforcement is enhanced through an appropriate thermal treatment. Copyright © 2004 Society of Chemical Industry     

Design guidelines for wireless sensor networks: communication, clustering and aggregation

When sensor nodes are organized in clusters, they could use either single hop or multi-hop mode of communication to send their data to their respective cluster heads. We present a systematic cost-based analysis of both the modes, and provide results that could serve as guidelines to decide which mode should be used for given settings. We determine closed form expressions for the required number of cluster heads and the required battery energy of nodes for both the modes. We also propose a hybrid communication mode which is a combination of single hop and multi-hop modes, and which is more cost-effective than either of the two modes. Our problem formulation also allows for the application to be taken into account in the overall design problem through a data aggregation model.     

Role of the central nucleus of the amygdala in olfactory heart rate conditioning.

The role of the central nucleus of the amygdala on olfactory heart rate conditioning in the infant rat was investigated. The conditioned stimulus (CS) consisted of a 10-s presentation of grape juice odor that was immediately followed by a 0.5-s, 0.35-mA subcutaneous shock. A sensitization control group was also run. Three days prior to testing, Ss received either bilateral electrolytic lesions of the central nucleus of the amygdala, sham lesions, or were left unperturbed. Results show that damage to the central nucleus of the amygdala severely impaired olfactory heart rate conditioning but that it had no deleterious effect on the heart rate orienting response to that stimulus or on the heart rate unconditioned response (UCR) to shock. Results are analogous to those in previous research on auditory heart rate conditioning and suggest that the central nucleus of the amygdala may constitute a necessary stage in the transduction of the CS into a cardiac conditioned response (CR) regardless of sensory modality. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Corrosion behaviour of AISI 304 stainless steel in presence of a biosurfactant produced by Pseudomonas fluorescens

Under certain conditions, some microorganisms are able to synthesize surface active compounds called biosurfactants (BS), which reduce the surface tension of water. BS characteristics depend on which microorganism produce them and therefore, on the microorganism culture conditions (temperature, pH, C, N-source,…). Numerous applications are known for these biomolecules, such as cleaning, bioremediation, and their use as a detergent, or in cosmetic formulations.Recently, a large amount of literature has been edited on the influence of BS on the interactions between pathogenic bacteria and inert surfaces. It has been shown that the modifications of surface properties by the adsorption of BS can reduce microbial adhesion.Some other studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; they are indeed used as an interesting corrosion inhibition tool. Therefore, it seems very interesting to study the impact of BS as environment-friendly (since biological and biodegradable) corrosion inhibitors.In the present work, an attempt was made to study the corrosion behaviour of AISI 304 stainless steel in presence of BS produced by a Gram-negative bacteria, Pseudomonas fluorescens (Pf495). Corrosion tests were achieved on several surface oxidation states. The surface morphology of the corroded specimens was investigated using SEM.     

A CASE STUDY ON CASE Its Evolution and Use at HHMI

Computer-aided software engineering (CASE) methodology and tools play an important role in the development of information systems and in the future direction of CASE. The amount of available information on this topic can be overwhelming. This article presents guidelines on selecting tools and a methodology based on the experience of the systems development team at Howard Hughes Medical Institute (HHMI), where CASE has been successfully implemented.     

Frontal Electroencephalogram Alpha Asymmetry During Sleep: Stability and Its Relation to Affective Style.

Electroencephalogram (EEG) alpha (8-12 Hz) asymmetries were collected from the mid-frontal and central regions during presleep wakefulness and Stage 1, Stage 2, and rapid eye movement (REM) sleep in 11 healthy right-handed participants who were free of psychiatric, neurological, and sleep problems. The authors found significant correlations between presleep wakefulness and different stages of sleep in the frontal, but not central, EEG alpha asymmetry measure. The strongest correlation was between presleep waking and REM sleep, replicating and extending relation earlier work to a normal population. The high degree of association between presleep waking and REM sleep may be a result of high cortical activation common to these states and may reflect a predisposition to different styles of emotional reactivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Receptor contributions to configural and elemental odor mixture perception.

Odor mixture perception can be configural (the mixture is qualitatively different from the components) or elemental (the components are recognizable). Some have argued that configural properties are dependent on chemical similarity and possible overlap at the receptor level. The authors show that a binary mixture in which both components activate the same receptor (17) has a configural odor, whereas a mixture that suppresses overlap has elemental odor properties. Rats trained to recognize mixtures of citronellal and octanal (strong 17 agonists) in many ratios rarely recognize the components, supporting configural representation of the odor mixture. However, when trained to recognize mixtures of citral (partial 17 agonist, inhibitor) and octanal, rats recognize 1 or both components over a wide range of ratios. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Creating satisfaction in steady dating relationships: The role of personal goals and situational affordances.

This research extends previous work indicating that individuals are more effective at regulating their behavior when they are in goal-congruent contexts by examining whether individuals particularly need concrete goal-relevant situational affordances once they are in these broadly affirming contexts. Specifically, the authors explore this issue by using the broad context of steady dating relationships (i.e., intimacy-relevant contexts), and considering the role of both intimacy goals and intimacy-affording daily life situations in producing relationship satisfaction and maintenance over time. Results indicate that those with a strong focus on intimacy experience considerable relationship satisfaction regardless of whether they spend time in daily life situations that facilitate intimacy, whereas those without such a focus depend for satisfaction on the presence of intimacy-conducive situations (e.g., time alone with one's partner, or social support from one's partner). Discussion focuses on the theoretical implications of these findings for the Person x Situation literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Analysis of group process: Cooperation of preschool children.

Studied cooperation from a group process perspective within the free play of children aged 2, 3, and 4 yrs. 72 children were distributed among 12 groups, with 3 boys and 3 girls in each group and 4 groups in each age. Two 30-min sessions were videotaped for each group to assess dimensions of cooperation such as the number of children in each subgroup, kind of play, and type of activity. Observational analyses showed that cooperation is present at every age but may develop rapidly at certain ages and plateau at others. Furthermore, results suggest that group play is not the culmination of a linear developmental process. Modifications in quantity between the 2 youngest and the oldest group suggest a cooperation continuum of its own, with large variations between groups within each age group. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stronger laws needed to stem spam

Without global legislation to combat spam, the problem will never be solved despite the fact that it is costs global businesses millions of dollars a year to tackle, believes the security industry.