Interfaces and programs for classroom experiments in biology

The advantages of the microcomputer as an instrument for the classroom laboratory — adaptability, price and its pedagogical role — are considered. Simple interfaces, including a tension transducer, are described for several physiological experiments. Programs can either be simple presentations of the data collected or be comprehensive with teaching modules, apparatus checks and data filing systems.     

Conditioning and extinction of tolerance to the hypothermic effect of ethanol in rats.

Examined the contribution of classical conditioning to tolerance to the hypothermic effect of ethanol in 56 male albino rats. During the tolerance acquisition phase, Ss were exposed at 4-day intervals to a distinctive set of environmental cues paired with injections of ethanol (1.4 g/kg, ip). Interspersed between these drug trials were exposures to an alternate set of cues paired with injections of saline. In addition, 3 groups experienced different amounts of stimulation and activity during drug exposure in order to determine whether "behavioral augmentation" of tolerance would occur. In subsequent tests, Ss were tolerant only in the presence of cues previously paired with ethanol. Moreover, this environmentally specific tolerance was associated with a conditioned hyporthermic response to placebo (saline) injections in the drug environment. An extinction procedure designed to weaken tolerance mediated by classical conditioning was also found to be effective. Evidence for conditioned tolerance was weakest in Ss experiencing low levels of activity during the initial drug exposure periods. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The cognitive correlates of third-grade skill in arithmetic, algorithmic computation, and arithmetic word problems.

The purpose of this study was to examine the cognitive correlates of 3rd-grade skill in arithmetic, algorithmic computation, and arithmetic word problems. Third graders (N = 312) were measured on language, nonverbal problem solving, concept formation, processing speed, long-term memory, working memory, phonological decoding, and sight word efficiency as well as on arithmetic, algorithmic computation, and arithmetic word problems. Teacher ratings of inattentive behavior also were collected. Path analysis indicated that arithmetic was linked to algorithmic computation and to arithmetic word problems and that inattentive behavior independently predicted all 3 aspects of mathematics performance. Other independent predictors of arithmetic were phonological decoding and processing speed. Other independent predictors of arithmetic word problems were nonverbal problem solving, concept formation, sight word efficiency, and language. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Single- Versus Dual-Drug Target: Effects in a Brief Abstinence Incentive Procedure.

The number of drugs targeted may have an important influence on the ability of drug abusers to abstain during motivational incentive procedures. The authors investigated outcomes in methadone maintenance patients (n = 58), who had evidence of both opiate and cocaine use, when continuous abstinence from cocaine only (single target) or from both cocaine and heroin (dual target) was required to earn $200 in voucher incentives over a 4-day period. Study patients were equally likely to initiate and sustain abstinence from cocaine under the single- versus the dual-drug target. They were more likely to initiate opiate abstinence under the dual-target condition, demonstrating sensitivity to reinforcer effects. Results suggest that adding a second drug target does not impede short-term cocaine abstinence initiation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of water content on thermal and dynamic mechanical properties of xanthan powder: A comparison between standard and novel techniques

In this work, the sorption isotherms of xanthan powder obtained under static and dynamic conditions and their fitting with mathematical models were discussed. The transitions within xanthan-water systems have been investigated using a standard material characterization technique - Differential Scanning Calorimetry (DSC) - and two novel techniques - Dynamic Mechanical Thermal Analysis (DMTA) material pocket and Phase Transition Analysis (PTA). It was found that within water-xanthan systems, the onset temperature for the melting of freezable water obtained from DSC method was in agreement with freezable water melting peaks obtained via DMTA material pocket at levels of hydration when the freezable water was present. Also, low-temperature transitions, related to polysaccharide-water interactions, were observed by both techniques within xanthan systems which contained no freezable water. However, the use of the PTA technique was limited to xanthan systems with low water content.     

An observer-based psychoacoustic procedure for use with young infants.

This article describes an observer-based technique for assessing auditory capacities of infants from 3 to 12 months of age. This technique, referred to as the Observer-based Psychoacoustic Procedure (OPP), combines features of the Forced-choice Preferential Looking technique developed by Teller (1979) and of Visual Reinforcement Audiometry (Moore, Thompson, & Thompson, 1975). The rationale behind the procedure and the specific techniques used in its application are detailed here. Psychometric functions and thresholds for pure-tone detection and frequency discrimination obtained with OPP are also presented. The results for 6-month-olds are compared with results from previous studies employing a visually reinforced head-turn procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unusual thermal relaxation of viscosity-and-shear-induced strain in poly(ether-ketones) synthesized in highly viscous polyphosphoric acid/P2O5 medium

We recently described an improved method to synthesize poly(ether-ketones) or PEKs. It utilized an optimized mixture of polyphosphoric acid (PPA) and P₂O₅ that is not only milder, less corrosive and less expensive than super-acid media, but also can play the multiple roles of solvent, Friedel-Crafts catalyst and dehydrating agent. The as-prepared PEKs from such a highly viscous reaction medium displayed unexpected, thermally induced relaxation exotherms regardless of the amorphous or semi-crystalline nature of polymer. This thermal behavior was not observed for the formally identical polymers [viz. pPEK or poly(oxy-1,4-phenylenecarbonyl-1,4-phenylene] which is normally semi-crystalline) that were separately prepared in a much less viscous mixture of methanesulfonic acid and P₂O₅ (Eaton's reagent) or N-methyl-2-pyrrolidinone (NMP). Such an observation was first made when both samples of pPEKs were subjected to the same thermal history and the thermal relaxation exotherms were observed only for the pPEK sample that was prepared in PPA/P₂O₅ medium. Further confirmation of viscosity-and-shear-induced strain stored in the as-synthesized PEKs was provided by a systematic annealing study with differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) analysis and Fourier-transform infrared spectroscopy (FT-IR). Based on these data, pPEK was successfully compression-molded in the temperature range of 230-250 °C which is more than 100 °C below its melting temperature.     

Drug-induced hypothermia and conditioned place aversion.

Examined the relationship between ethanol's thermal and motivational effects in a place conditioning task. In 3 experiments, male albino rats were exposed to a differential conditioning procedure that paired a distinctive tactile stimulus with ethanol (1.2 or 1.8 g/kg) or lithium chloride (3 meq/kg); a different stimulus was paired with saline. Different groups were exposed to ambient temperatures (Ta) of 5°, 21°, or 32°C during each 60-min conditioning trial. Both ethanol and lithium chloride produced hypothermia and conditioned place aversion in rats conditioned at normal Ta. Exposure to high Ta reduced drug-induced hypothermia, increased activity, and decreased conditioned place aversion. Exposure to low Ta did not enhance drug-induced hypothermia or change conditioned place aversion. In general, these findings support the suggestion that the hedonic effects of ethanol and lithium chloride interact with their thermal effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)