Adaptations, exaptations, and spandrels.

Adaptation and natural selection are central concepts in the emerging science of evolutionary psychology. Natural selection is the only known causal process capable of producing complex functional organic mechanisms. These adaptations, along with their incidental by-products and a residue of noise, comprise all forms of life. Recently, S. J. Gould (1991) proposed that exaptations and spandrels may be more important than adaptations for evolutionary psychology. These refer to features that did not originally arise for their current use but rather were co-opted for new purposes. He suggested that many important phenomena—such as art, language, commerce, and war—although evolutionary in origin, are incidental spandrels of the large human brain. The authors outline the conceptual and evidentiary standards that apply to adaptations, exaptations, and spandrels and discuss the relative utility of these concepts for psychological science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Direct frequency changer operation under a new scalar controlalgorithm

A thorough analysis of a scalar control method for the operation of direct frequency changers (DFC) using bidirectional switches operating at high switching frequencies is proposed. The method allows full control over voltage and frequency at the output port and the input side power displacement factor, with little effect on the frequency spectrum of either the output voltage or input currents. The method uses the instantaneous voltage ratio of specific input phase voltages to generate the active and zero states of the various switches. A voltage transfer ratio as high as 0.87 is obtained under synchronous and asynchronous operation with a conventionally connected three-phase load. Analysis shows that the input power displacement factor is independent of load characteristics. The power displacement can be precisely controlled by proper adjustments of the timing sequence. Synchronization error in the timing sequence affects both the input power displacement and the voltage transfer ratio     

Family resemblance in attitudes to foods.

Although it seems likely that family experience should be a major factor in the acquisition of food preferences and attitudes to foods, prior research has not justified assignment of a significant portion of variance to family influences. The present study compared young adults with their parents and explored attitudes to food, especially sensitivity to cleanliness and contamination of foods, as well as food preferences. Questionnaires were answered by 17 Christian and 17 Jewish university students, their parents, and 41 11–36 yr old siblings. Results indicate small positive parent–child correlations for food preferences and considerably larger correlations in the area of disgust or contamination sensitivity. Children's preferences and attitudes were about equally related to those of their mother and father. Some small ethnic-group effects were found in contamination sensitivity; these were minor in comparison to the family effects. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Are adult children of dysfunctional families with alcoholism different from adult children of dysfunctional families without alcoholism? A look at committed, intimate relationships.

Investigating the validity of classifying adult children of dysfunctional families with alcoholism (ACDFAs) as a unique population, this study compared ACDFAs with adult children of dysfunctional families without alcoholism (ACDFs) and adult children of functional families (ACFFs) on current relationship satisfaction. Participants (N ?=?126) were from a community sample. No significant difference between the ACDFAs and ACDFs was found; however, both ACDFAs and ACDFs displayed significantly more difficulty with problem-solving communication than the ACFFs. Regression results indicated that dysfunction in the family of origin is significantly related to global distress and difficulties with problem-solving communication in current intimate relationships. Results do not lend support to the utility of classifying ACDFAs as a unique population. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Natural Voltage-Gated Sodium Channel Ligands: Biosynthesis and Biology

Natural product biosynthetic pathways are composed of enzymes that use powerful chemistry to assemble complex molecules. Small molecule neurotoxins are examples of natural products with intricate scaffolds which often have high affinities for their biological targets. The focus of this Minireview is small molecule neurotoxins targeting voltage-gated sodium channels (VGSCs) and the state of knowledge on their associated biosynthetic pathways. There are three small molecule neurotoxin receptor sites on VGSCs associated with three different classes of molecules: guanidinium toxins, alkaloid toxins, and ladder polyethers. Each of these types of toxins have unique structural features which are assembled by biosynthetic enzymes and the extent of information known about these enzymes varies among each class. The biosynthetic enzymes involved in the formation of these toxins have the potential to become useful tools in the efficient synthesis of VGSC probes.     

Identification and quantification of oxidized organic aerosol compounds using derivatization,liquid chromatography,and chemical ionization mass spectrometry

A systematic approach for identifying and quantifying molecular components of complex organic aerosol mixtures is presented. The approach combines methods developed previously for derivatizing carbonyl, hydroxyl, carboxyl, and ester functional groups, which are commonly present in oxidized organic aerosol, with liquid chromatography, UV detection, and chemical ionization-ion trap mass spectrometry. The original derivatization-spectrophotometric methods were modified for compatibility with liquid chromatography and then evaluated by analyzing a variety of standard compounds that contain one or more functional groups. Detection limits for carbonyl, hydroxyl, carboxyl, and ester analysis are approximately 0.003, 0.02, 0.01, and 1 nmole, respectively. Mass spectral analysis of derivatives using isobutane and ammonia as reagent gases for chemical ionization can be used to determine compound molecular weight, and characteristic fragmentation patterns provide structural information for use in compound identification. The methods will be useful for analyzing the chemical composition of secondary organic aerosol (SOA) formed in laboratory studies to obtain information needed to develop quantitative reaction mechanisms that can be incorporated into atmospheric models to better predict the formation, composition, and fate of SOA.

Copyright © 2017 American Association for Aerosol Research     

铝酸钙水泥、硅酸盐水泥和β-半水石膏混合物中钙矾石的膨胀性能

本文利用现场同步加速X-射线衍射、等温量热仪和膨胀测量等手段,研究了在20℃,100%相对湿度下,由25%(重量比)的铝酸钙水泥、12.5%的硅酸盐水泥、12.5%的β-半水石膏和50%的水组成的浆体的水化。水化伊始,首先形成了石膏和钙矾石,同时半水石膏也相应消耗(0-45min内)。随后石膏继续消耗,钙矾石持续形成,2h45min后石膏消耗完毕,铝酸盐-AFm开始形成,同时钙矾石的数量在7h内保持不变。热曲线的第一个峰源自机械搅拌、初始润湿和溶解,还有钙矾石和石膏的形成,第二个峰为石膏被钙矾石所替代,第三个对应于铝酸盐-AFm的形成。石膏被钙矾石替代伴随着0.7%平均线性膨胀。     

STABILITY OF WHISKERS AND INTERFACIAL MICROSTRUCTURE IN ALUMINUM MATRIX COMPOSITES REINFORCED BY K_2O·8TiO_2 WHISKERS

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