The value and utility of the 1992 ethics code.

This article describes organizational and conceptual strengths of the current American Psychological Association's ethics code within the context of the diversity of activities in which psychologists are engaged and the constantly changing realities of professional and legal responsibilities. The article places into practical perspective (a) the revised format, choice of wording, and enforceability of the code; (b) protections for students, supervisees, research participants, and diverse groups; (c) requirements for informed consent to psychotherapy, continuity of care, and appropriate termination; (d) restrictions regarding multiple relations; and (e) standards particularly relevant to teaching, research, forensic, and managed care contexts. Discussion aims at assisting psychologists in using the ethical principles and standards to conduct their activities in morally responsible ways and avoid potential ethical violations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory frequency discrimination in infancy.

Investigated the ability of 14 5–8 mo olds and 5 college students to detect changes in the frequency of pure tones. A head turn for visual reinforcement technique was used to obtain difference thresholds for infants and adults at 1,000, 2,000, and 3,000 Hz. With signals presented at 70 db above adult detection thresholds, infants reliably detected frequency changes on the order of 2%, whereas adults detected changes of about 1%. Data confirm previous findings indicating that infants can distinguish different frequencies and can make relatively fine discriminations. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lipid nanotubes as substrates for helical crystallization of macromolecules

A general approach for crystallization of proteins in a fast and simple manner would be of immense interest to biologists studying protein structure-function relationships. Here, we describe a method that we have developed for promoting the formation of helical arrays of proteins and macromolecular assemblies. Electron micrographs of the arrays are suitable for helical image analysis and three-dimensional reconstruction. We show that hydrated mixtures of the glycolipid galactosylceramide (GalCer) and derivatized lipids or charged lipids form unilamellar nanotubules. The tubules bind proteins in a specific manner via high affinity ligands on the polar head groups of the lipid or via electrostatic interactions. By doping the GalCer with a novel nickel-containing lipid, we have been able to form helical arrays of two histidine-tagged proteins. Similarly, doping with a biotinylated lipid allows crystallization of streptavidin. Finally, three proteins with affinity for positively or negatively charged lipid layers formed helical arrays on appropriately charged tubules. The generality of this method may allow a wide variety of proteins to be crystallized on lipid nanotubes under physiological conditions.     

Traits as dimensions or categories? Developmental change in the understanding of trait terms.

Recent research has suggested that young children have relatively well-developed trait concepts. However, this literature overlooks potential age-related differences in children's appreciation of the fundamentally dimensional nature of traits. In Study 1, we presented 4-, 5-, and 7-year-old children and adults with sets of characters and asked them to indicate the preferences of a target character who shared appearance attributes with one character (appearance match) and shared a common trait with the other character (trait match). Traits were presented in a way that emphasized either their categorical or their dimensional nature. When the dimensional nature of trait terms was emphasized, the youngest children made fewer trait-based inferences, and the use of traits increased with age. In Study 2, we gave 4-year-old children and adults the same task except that the extent to which appearance cues could serve as a meaningful basis of judgment was varied. Results were consistent with the findings of Study 1, although children were more likely to rely on dimensional presentations of traits in the absence of strong appearance cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The specific bronchial provocation test in the diagnosis of occupational asthma

Specific bronchial challenge (SBC) testing is a key technique for diagnosing the origin of occupational asthma (OA). SBC is indicated in specific circumstances, including whenever several agents present in the work environment may be the cause of OA, when new or unusual occupational agents need to be identified, when evidence for legal action is required, or when research is conducted. SBC procedures are not standardized, because of the great diversity of occupational agents and the variety of physical and chemical properties involved. Thus, SBC testing with agents found in fumes, gases or vapors can be administered in special cabins or in closed circuits with continuous monitoring of sub-irritant concentrations. Agents found in dust, most but not all of which have high molecular weights, may be appropriate for routine SBC testing in an allergy laboratory. This paper will treat only these cases. SBC must be formed in specialized centers by experienced personnel, as it is a sophisticated and potentially dangerous technique. We describe a series of 20 patients diagnosed of OA in our unit over the past two years in whom SBC provided an etiologic diagnosis. All were exposed to dust or aerosols at work. The cause was a substance of high molecular weight in 17 cases, and low molecular weight in 3. The procedure used is described and models of bronchial response are discussed.