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Selected AbstractsEthnic variations in facial skin neurosensitivity assessed by capsaicin detection thresholdsCONTACT DERMATITIS, Issue 6 2009Roland Jourdain Background: Ethnic variations in sensitive skin have not been thoroughly explored and remain controversial. Objective: To objectively assess ethnic variations in facial skin neurosensitivity through individual detection thresholds of topically applied capsaicin. Patients/Methods: The single-blind, controlled study was performed in 144 women from three ethnicities: Asian, African, and Caucasian. Five solutions with increasing capsaicin concentration were successively applied to one side of nasolabial folds, while the other side simultaneously received the vehicle as control. The test was discontinued when the volunteer reported on the capsaicin side a sensation whatever its nature. Otherwise the experimenter continued the test, using the next solution with higher capsaicin content and so on, until the subject experienced a sensation on the capsaicin side. Results: Each ethnic group was divided into six sub-groups according to the level of sensitivity to capsaicin, i.e. from detection of the lowest concentration up to no detection of the highest concentration, 100-fold higher. Asian women tended to have higher capsaicin detection thresholds than Caucasians, but lower thresholds than Africans. Nevertheless, the distribution did not greatly differ between the three ethnicities. Conclusions: The capsaicin skin neurosensitivity test is painless and the changes across individuals of different ethnic backgrounds appear minimal. [source] Children's narratives and patterns of cardiac reactivityDEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2004Yair Bar-Haim Abstract The present study examines the associations between narrative processing, narrative production, and cardiac rate and variability in children. Heart period (HP) and vagal tone (VT) were computed for fifty-eight 7-year-olds (29 males) during a resting baseline and during epochs in which the children listened to and completed a selected set of story-stems from the MacArthur Story-Stem Battery (I. Bretherton, D. Oppenheim, H. Buchsbaum, R. N. Emde, & the MacArthur Narrative Group, 1990). Significant decreases in HP and VT were observed between a resting baseline and epochs of story-stem presentation by the experimenter. In addition, HP was shorter and VT lower during children's narrative production to emotionally laden story-stems compared with narration to a neutral story-stem. Furthermore, narrative and cardiac responses to stories containing separation,reunion themes reflected increased emotional and cognitive load compared with responses to stories that did not contain such themes. Finally, children who showed VT suppression in response to emotion-laden stories produced more coherent and adaptive narratives compared to those of children who did not show VT suppression. The findings suggest interplay between the cognitive-emotional processes associated with narrative processing and production and cardiac activation patterns. © 2004 Wiley Periodicals, Inc. Dev Psychobiol 44: 238,249, 2004. [source] Essentialism in the absence of language?DEVELOPMENTAL SCIENCE, Issue 4 2010Evidence from rhesus monkeys (Macaca mulatta) We explored whether rhesus monkeys (Macaca mulatta) share one important feature of human essentialist reasoning: the capacity to track category membership across radical featural transformations. Specifically, we examined whether monkeys , like children (Keil, 1989) , expect a transformed object to have the internal properties of its original category. In two experiments, monkeys watched as an experimenter visually transformed a familiar fruit (e.g. apple) into a new kind of fruit (e.g. coconut) either by placing a fruit exterior over the original, or by removing an exterior shell and revealing the inside kind of fruit. The experimenter then pretended to place an inside piece of the transformed fruit into a box which the monkey was allowed to search. Results indicated that monkeys searched the box longer when they found a piece of fruit inconsistent with the inside kind, suggesting that the monkeys expected that the inside of the transformed fruit would taste like the innermost kind they saw. These results suggest that monkeys may share at least one aspect of psychological essentialism: They maintain category-specific expectations about an object's internal properties even when that object's external properties change. These results therefore suggest that some essentialist expectations may emerge in the absence of language, and thus raise the possibility that such tendencies may emerge earlier in human development than has previously been considered. [source] Children's use of gesture to resolve lexical ambiguityDEVELOPMENTAL SCIENCE, Issue 6 2009Evan Kidd We report on a study investigating 3,5-year-old children's use of gesture to resolve lexical ambiguity. Children were told three short stories that contained two homonym senses; for example, bat (flying mammal) and bat (sports equipment). They were then asked to re-tell these stories to a second experimenter. The data were coded for the means that children used during attempts at disambiguation: speech, gesture, or a combination of the two. The results indicated that the 3-year-old children rarely disambiguated the two senses, mainly using deictic pointing gestures during attempts at disambiguation. In contrast, the 4-year-old children attempted to disambiguate the two senses more often, using a larger proportion of iconic gestures than the other children. The 5-year-old children used less iconic gestures than the 4-year-olds, but unlike the 3-year-olds, were able to disambiguate the senses through the verbal channel. The results highlight the value of gesture to the development of children's language and communication skills. [source] Biological bases of face preference in 6-week-old infantsDEVELOPMENTAL SCIENCE, Issue 5 2003Elliott M. Blass Six-week-old infants (N =40) who started the experiment in either a calm or crying state, received sucrose from an experimenter, while in eye contact with her. Sucrose was delivered either by syringe or on a pacifier. After 3.5 min., the experimenter retired, the mother came into the test room and placed her infant over her shoulder en face with a video camera. The experimenter and a confederate, both dressed identically, sat in front of and slightly to either side of the infant and the infant could choose to look at either experimenter. To minimize position bias, experimenters switched sides every 30 sec. To maintain a stable level of infant attention, they simultaneously called the baby's name at 10 sec. intervals. When an infant looked at one or the other experimenters, she raised her thumb in camera view. Only crying infants who sucked a sweet pacifier showed a preference for their experimenter. As a group none of the other infants did so. However, there was a wide distribution of sucking times in calm week 6 infants. Choice was linearly related to sucking duration. Infants who sucked for substantial periods of time, showed a strong preference for the experimenter. Those who sucked for minimal periods of time strongly preferred the confederate. Based on these findings and ones from 9- and 12-week-old infants, a model is presented in which preference in this experimental paradigm is determined by idealized levels of central activation. These levels may be inferred from the normal crying function at a particular age. [source] Successful Application of Video-Projected Human Images for Signalling to DogsETHOLOGY, Issue 10 2003Péter Pongrácz Dogs were tested (1) in a two-way choice experiment, where the experimenter indicated a baited bowl by pointing; and (2) in a task where the owner was asked to command the dog to execute simple obedience tasks. In expt 1 dogs (n = 10) were tested at first in the presence of the experimenter (three dimensional condition, 3D), that was followed by a series of pointing trials when the life-sized image of the experimenter was projected onto the wall by the means of a video-projector (two dimensional condition, 2D). Dogs performed correctly more often than expected by chance in both 3D and 2D conditions. In expt 2 the commanding owner was either present in the room (3D), or her/his image was projected on the screen (2D), or only her/his voice was audible for the dog through a speaker (0D). The performance of the dogs (n = 10) decreased to great extent comparing the 3D and 0D condition, as the number of different actions the dogs obeyed was significantly less in the 0D condition. However, there was no difference in the number of different actions obeyed in the 3D and 2D conditions. Our results show that dogs readily obey life-sized, interactive moving image in various communicative situtations. We suppose that the difference between 2D and 3D conditions can be attributed partially to the lack of some additional communicative signals as sounds (verbal cues) and odours (from the human), and to some changes in the context. [source] MDMA self-administration in rats: acquisition, progressive ratio responding and serotonin transporter bindingEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2007Susan Schenk Abstract 3,4-Methylenedioxymethamphetamine (MDMA) self-administration has been shown in animals with extensive drug histories, but only a small number of studies have examined high rates of responding maintained by MDMA in previously drug-naïve animals. In the present study, influence of dose (0.25 or 1.0 mg/kg/infusion) on the acquisition of MDMA self-administration was measured during daily 6-h sessions. Dose,effect data were obtained for MDMA (0.25,1.0 mg/kg/infusion) self-administration under a progressive ratio (PR) schedule of reinforcement. The effect of experimenter- or self-administered MDMA on [3H] paroxetine binding in several brain regions was measured. Acquisition of MDMA self-administration was highly variable and not different for 0.25 or 1.0 mg/kg/infusion progressed with approximately 60% of the rats acquiring reliable self-administration during the 15-day test period. The percentage of rats that acquired MDMA self-administration was lower than the percentage of rats that acquired cocaine (0.5 mg/kg/infusion) self-administration, and cocaine self-administration was acquired with a shorter latency. Responding maintained by MDMA was dose dependent, and breakpoints under a PR schedule increased with dose. Radioligand binding and autoradiography demonstrated lower densities of serotonin transporter sites (SERT) in MDMA self-administering rats as compared with controls across brain regions. The reduction in SERT densities was comparable in magnitude to rats treated with experimenter-administered doses of MDMA. These data support the idea that MDMA is a drug with high abuse liability, and long-term self-administration may lead to long-lasting deficits in serotonin neurotransmission. [source] PRECISION OF HERBIVORE TOLERANCE EXPERIMENTS WITH IMPOSED AND NATURAL DAMAGEEVOLUTION, Issue 3 2003Kari Lehtilä Abstract Tiffin and Inouye (2000) discussed the use of natural and imposed (controlled) damage in experiments of herbivore tolerance. They constructed a statistical model of the effect of herbivory on plant fitness, including damage level and an environmental factor as the independent factors, in which tolerance is defined as a slope of the regression line when damage level is regressed with plant fitness. They claim that while experiments with imposed damage are more accurate (i.e., they give a more correct estimate of tolerance), experiments with natural damage are more precise under a wide range of parameter values (i.e., tolerance estimates explain a larger part of variation in fitness). I show, however, that experiments with imposed damage are less precise only when an experimenter uses an experimental design that has weaker statistical power than in experiments with natural herbivory. The experimenter can nevertheless control the damage levels to optimize the experimental designs. For instance, when half of the experimental plants are left undamaged and the other half treated with maximal relevant damage level, experiments with imposed damage are almost always much more precise than experiments with natural damage. [source] Common variations in the pretest environment influence genotypic comparisons in models of anxietyGENES, BRAIN AND BEHAVIOR, Issue 7 2005G. S. Izídio The behavioral characterization of rodent strains in different studies and laboratories can provide unreplicable results even when genotypes are kept constant and environmental control is maximized. In the present study, the influence of common laboratory environmental variables and their interaction with genotype on the results of behavioral tests of anxiety/emotionality were investigated. To this end, the inbred rat strains Lewis (LEW) and spontaneously hypertensive rats (SHR), which are known to differ for numerous emotionality-related behaviors, were tested in the open field (OF), elevated plus maze (EPM) and black/white box (BWB), while three environmental factors were systematically controlled and analyzed: (1) the experimenter handling the animal (familiar or unfamiliar); (2) the position of the home cage (top or bottom shelf of the rack) and (3) the behavioral state of the animal immediately before the test (arousal or rest). Experimenter familiarity did not alter the behavior of rats in the OF. Cage position, on the other hand, influenced the behavior in the OF and BWB, with rats housed in top cages appearing less anxious like than those housed in the bottom. In the BWB (but not in the OF), these effects were genotype dependent. Finally, the behavioral state of the animals prior to testing altered the results of the EPM in a strain-dependent manner, with some anxiety-related genotypic differences being found only among rats that were aroused in their home cages. This study showed that common variations in the laboratory environment interact with genotype in behavioral tests of anxiety/emotionality. Recognizing and understanding such variations can help in the design of more effective experiments. [source] Involuntary, unreinforced (pure) spatial learning is impaired by fimbria-fornix but not by dorsal hippocampus lesionsHIPPOCAMPUS, Issue 3 2003Norman M. White Abstract Pure spatial learning occurs when rats acquire information about an environment while exploring it in the absence of reinforcers. We previously reported that voluntary, unreinforced exploration of a radial maze retards subsequent reinforced conditioned cue preference (CCP) learning in the same maze. In the present experiment, we examined the effects of involuntary, unreinforced pre-exposure to a radial maze. During pre-exposure, rats were moved by an experimenter between the ends of two arms of a radial maze five times in 30 min. This form of pre-exposure retarded CCP learning, whereas rats that were not pre-exposed and rats that were pre-exposed to a maze in a different room displayed normal CCP learning. These findings suggest that some information specific to the maze environment was acquired during involuntary unreinforced pre-exposure to it. In experiment 2, the retardation of reinforced CCP learning by involuntary unreinforced pre-exposure was eliminated by fimbria-fornix lesions made before pre-exposure but was unaffected by fimbria-fornix lesions made after pre-exposure but before training. Large neurotoxic lesions of the dorsal hippocampus made before pre-exposure had no effect on the retardation of CCP learning, but the rats with these lesions were impaired on a standard test of reinforced spatial learning in a water maze. The lesion effects in experiment 2 are similar to those previously reported for voluntary exploration and suggest that pure spatial learning may occur during both voluntary exploration of and involuntary exposure to an environment in the absence of reinforcers. Pure spatial learning can apparently occur with exposure to two different locations within an environment, but the rats do not have to move between the locations voluntarily. An intact fimbria-fornix is required for acquisition but not expression of this form of learning. The hippocampus is not involved in this form of learning. Hippocampus 2003;13:324,333. © 2003 Wiley-Liss, Inc. [source] Common Coding of Observation and Execution of Action in 9-Month-Old InfantsINFANCY, Issue 1 2006Matthew R. Longo Do 9-month-old infants motorically simulate actions they perceive others perform? Two experiments tested whether action observation, like overt reaching, is sufficient to elicit the Piagetian A-not-B error. Infants recovered a toy hidden at location A or observed an experimenter recover the toy. After the toy was hidden at location B, infants in both conditions perseverated in reaching to A, demonstrating that active search by the infant is not necessary for the A-not-B error. Consistent with prior research, infants displayed an ipsilateral bias when reaching, the so-called mysterious midline barrier. A similar ipsilateral bias was also observed depending on the manner in which the experimenter reached; infants perseverated following observation of ipsi- but not contralateral reaches by the experimenter. Thus, infants perseverated only following observation of actions they themselves were able to perform, suggesting that they coded others' actions in terms of motor simulation. [source] The Influence of Labels, Non-Labeling Sounds, and Source of Auditory Input on 9- and 15-Month-Olds' Object CategorizationINFANCY, Issue 3 2003Anne L. Fulkerson This experiment examines the joint influence of auditory and social cues on infants' basic-level and global categorization. Nine- and fifteen-month-olds were familiarized to a series of category exemplars in an object-examining task. Objects were introduced with a labeling phrase, a non-labeling sound, or no sound, and auditory input was presented orally by the experimenter or played on a hidden voice recorder. Novel objects from the familiarized category and a contrasting category were then presented. Results of analyses performed on novelty preference scores indicated that infants demonstrated basic-level categorization in all conditions. However, infants at both age levels only demonstrated global categorization when labeling phrases were introduced. In addition, labels led to global categorization in 9-month-olds regardless of the source of those labels; however, labels only led to global categorization in 15-month-olds when the labels were presented orally by the experimenter. [source] Task-to-Task Vagal Regulation: Relations With Language and Play in 20-Month-Old ChildrenINFANCY, Issue 3 2000Patricia E. Suess In this article we report patterns of task-to-task vagal tone change across multiple language and play tasks as well as associations between these patterns of task-to-task vagal tone change and language and play performance in 20-month-old girls and boys. Although initially different in vagal tone suppression during solitary play, girls and boys exhibited similar group patterns of vagal reengagement during successive language and play tasks with their mothers and with an experimenter. In terms of individual differences, vagal suppression during solitary play and vagal reengagement during social interactive tasks predicted language and play performance. Gender differences emerged in patterns of predictive relations: Task-to-task vagal changes predicted primarily play performance in girls and language performance in boys. These findings expose the effects of social context on directional changes in task-to-task vagal tone and speak to the functional role of appropriate vagal regulation in young children's language and play performance. [source] Gender-related differences in neonatal imitationINFANT AND CHILD DEVELOPMENT, Issue 3 2007Emese Nagy Abstract Socio-emotional behaviour is in part sex-related in humans, although the contribution of the biological and socio-cultural factors is not yet known. This study explores sex-related differences during the earliest communicative exchange, the neonatal imitation in 43 newborn infants (3,96 hours old) using an index finger extension imitative gesture. Results showed that although the experimenter presented comparable stimuli to both sexes, and the total number of movements was similar in boys and girls, girls showed more fine motor movements, a higher number of specific imitative gestures, responded faster during the imitation and showed a higher baseline heart rate during the experiment. Newborn girls, with their faster and more accurate imitative abilities, may create a more responsive and interactive social environment, which in turn may lead to differences in socio-emotional and cognitive development between girls and boys. Copyright © 2007 John Wiley & Sons, Ltd. [source] Use of experimenter-given directional cues by a young white-handed gibbon (Hylobates lar)1JAPANESE PSYCHOLOGICAL RESEARCH, Issue 3 2004YOICHI INOUE Abstract:, A three-year-old white-handed gibbon (Hylobates lar) was tested in terms of her ability to follow experimenter-given directional cues in an object-choice task. Four conditions were run: the experimenter baited one of two cups and then gave one of the following four directional cues: (a) pointing at the baited cup from a short distance (5 cm); (b) pointing at the target from a long distance (20 cm); (c) orienting body, head, and eyes toward the baited cup; and (d) orienting eyes only toward the baited cup. A young gibbon was able to use all of the experimenter-given cues to obtain hidden food rewards. Several possible reasons for the gibbon's superior performance in comparison to other primates reported in the existing literature were discussed. [source] Single-crystal structure validation with the program PLATONJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2003A. L. Spek The results of a single-crystal structure determination when in CIF format can now be validated routinely by automatic procedures. In this way, many errors in published papers can be avoided. The validation software generates a set of ALERTS detailing issues to be addressed by the experimenter, author, referee and publication journal. Validation was pioneered by the IUCr journal Acta Crystallographica Section C and is currently standard procedure for structures submitted for publication in all IUCr journals. The implementation of validation procedures by other journals is in progress. This paper describes the concepts of validation and the classes of checks that are carried out by the program PLATON as part of the IUCr checkCIF facility. PLATON validation can be run at any stage of the structure refinement, independent of the structure determination package used, and is recommended for use as a routine tool during or at least at the completion of every structure determination. Two examples are discussed where proper validation procedures could have avoided the publication of incorrect structures that had serious consequences for the chemistry involved. [source] Clear strategy screens for macromolecular crystallizationJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2001Andrzej Marek Brzozowski The development of high-throughput crystallography combined with the wealth of already accumulated information about protein crystallization properties requires constant revision of current crystallization screening procedures. Two complementary 6 × 4 matrix `clear strategy screens' (CSS) have been developed and tested on a number of previously non-crystallized proteins. The screens yielded diffraction-quality crystals of a wide range of proteins (enzymes, transcription factors, structural proteins, etc.) in cases where the applications of commercially available screens were unsuccessful. Both their inherently simple design and their flexible nature provide an experimenter with a logical platform for further modification and optimization. Furthermore, the screens facilitate cryoprotection and potential incorporation of anomalous scatterers for multiple/single-wavelength anomalous dispersion (MAD/SAD) experiments. [source] The effects of alcohol and the salience of aggressive cues on triggered displaced aggressionAGGRESSIVE BEHAVIOR, Issue 1 2008Thomas F. Denson Abstract Alcohol increases the aggression-augmenting effects of provocation. Theories of alcohol and aggression suggest that impaired cognitive processing induced by acute intoxication leads individuals to process aggression-inducing social cues differently depending on whether they are high or low in salience. We examined the effects of intoxication and aggressive cue salience within the triggered displaced aggression paradigm. An ethnically diverse sample of 74 primarily young adult participants (40 men and 34 women; M=23.28, SD=3.14 years) were recruited from the university community and surrounding area. All participants were provoked by an experimenter, randomly assigned to a 2 (alcohol condition: alcohol vs. placebo) × 2 (trigger salience: high vs. low salience) between-subjects design, and then given the opportunity to aggress against the undeserving triggering agent. As expected, intoxication combined with a salient triggering cue elicited the most displaced aggression among all conditions. These results provide the first evidence that the effect of alcohol on triggered displaced aggression is moderated by the salience of the triggering event. Aggr. Behav. 34:25,33, 2008. © 2007 Wiley-Liss, Inc. [source] Experimentally manipulated change in children's proactive and reactive aggressive behaviorAGGRESSIVE BEHAVIOR, Issue 3 2003Nancy C. Phillips Abstract The current study assessed the effectiveness of two behavior manipulations created to differentially lower aggressive responses in a laboratory task. It was hypothesized that the reactive anger manipulation would have the greatest effect for reactive aggressive behavior and the instrumental manipulation would significantly affect proactive aggressive behavior and slightly affect the reactive behavior. Fifty participants played pinball in competition for points against an unknown peer, whose responses were actually controlled by the experimenter. Participants could push a noise button, sending the peer an annoying noise; a tilt button, interfering with the opponent's game; or a no answer button, offering a pro-social alternative to aggression. After playing four rounds, participants were randomly assigned to either a reactive anger or a positive instrumental manipulation group; they then played pinball again for four rounds. Results indicate that the instrumental manipulation significantly lowered aggressive responses for both reactive and proactive behavior. The reactive manipulation effected aggressive responses only for use of the noise button and produced significantly lower levels of anger. Aggr. Behav. 29:215,227, 2003. © 2003 Wiley-Liss, Inc. [source] Selection experiments and the study of phenotypic plasticity,JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2002S. M. Scheiner Abstract Laboratory selection experiments are powerful tools for establishing evolutionary potentials. Such experiments provide two types of information, knowledge about genetic architecture and insight into evolutionary dynamics. They can be roughly classified into two types: (1) artificial selection in which the experimenter selects on a focal trait or trait index, and (2) quasi-natural selection in which the experimenter establishes a set of environmental conditions and then allows the population to evolve. Both approaches have been used in the study of phenotypic plasticity. Artificial selection experiments have taken various forms including: selection directly on a reaction norm, selection on a trait in multiple environments, and selection on a trait in a single environment. In the latter experiments, evolution of phenotypic plasticity is investigated as a correlated response. Quasi-natural selection experiments have examined the effects of both spatial and temporal variation. I describe how to carry out such experiments, summarize past efforts, and suggest further avenues of research. [source] Interpretation of the temperature dependence of equilibrium and rate constantsJOURNAL OF MOLECULAR RECOGNITION, Issue 5 2006Donald J. Winzor Abstract The objective of this review is to draw attention to potential pitfalls in attempts to glean mechanistic information from the magnitudes of standard enthalpies and entropies derived from the temperature dependence of equilibrium and rate constants for protein interactions. Problems arise because the minimalist model that suffices to describe the energy differences between initial and final states usually comprises a set of linked equilibria, each of which is characterized by its own energetics. For example, because the overall standard enthalpy is a composite of those individual values, a positive magnitude for ,Ho can still arise despite all reactions within the subset being characterized by negative enthalpy changes: designation of the reaction as being entropy driven is thus equivocal. An experimenter must always bear in mind the fact that any mechanistic interpretation of the magnitudes of thermodynamic parameters refers to the reaction model rather than the experimental system For the same reason there is little point in subjecting the temperature dependence of rate constants for protein interactions to transition-state analysis. If comparisons with reported values of standard enthalpy and entropy of activation are needed, they are readily calculated from the empirical Arrhenius parameters. Copyright © 2006 John Wiley & Sons, Ltd. [source] Advances in membrane receptor screening and analysisJOURNAL OF MOLECULAR RECOGNITION, Issue 4 2004Matthew A. Cooper Abstract During the last decade there has been significant progress in the development of analytical techniques for the screening of ligand binding to membranes and membrane receptors. This review focuses on developments using label-free assays that facilitate ligand,membrane,receptor screening without the need for chemical-, biological- or radiological-labelled reagents. These assays include acoustic, optical surface plasmon resonance biosensing, sedimentation (analytical ultracentrifugation), chromatographic assays, isothermal titration calorimetry and differential scanning calorimetry. The merits and applications of cell-based screening systems and of different model membrane systems, including planar supported lipid layers, bead-supported membranes and lipid micro-arrays, are discussed. Recent advances involving more established techniques including intrinsic fluorescence, FRET spectroscopy, scintillation proximity assays and automated patch clamping are presented along with applications to peripheral membrane proteins, ion channels and G protein-coupled receptors. Novel high-throughput assays for determination of drug- and protein-partitioning in membranes are also highlighted. To aid the experimenter, a brief synopsis of the techniques commonly employed to purify and reconstitute membranes and membrane receptors is included. Copyright © 2004 John Wiley & Sons, Ltd [source] A new approach to batch process optimization using experimental designAICHE JOURNAL, Issue 2 2009Paul J. Wissmann Abstract Empirical and mechanistic experimental design methods are combined to construct partial models, which are, thus, used to design a process. The grid algorithm restricts the next experimental point to potential process optima, according to the confidence intervals around the optimal points, and works with any experimental design algorithm such as D-optimal. Two case studies show the advantages of implementing the grid algorithm. On average the improvement due to the grid algorithm was 15,20% in the first case study. The second case study is based on thin film growth using four potential models, with the most probable model used for experimental design. The grid algorithm balances the trade-off between two extremes: D-optimal designs and sampling at the predicted optimal point. The methodology presented shows that the experimenter does not have to decide ahead of time on purely empirical or mechanistic experimental design methods, since both may be useful. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Maternal Genotype Influences Stress Reactivity of Vasopressin-Deficient Brattleboro RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 12 2003D. Zelena Abstract The role of vasopressin, cosecreted with corticotropin-releasing hormone (CRH), in stress is debated, because both normal as well as reduced adrenocorticotropin hormone (ACTH) rise to an acute challenge has been reported in Brattleboro rats genetically lacking vasopressin (di/di). Because di/di pups could be born either from di/+ (heterozygous) or from di/di mothers, and maternal influence is known to modify adult responsiveness, we investigated whether the influence of maternal genotype could explain the variability. Adult rats from mothers with different genotypes were stressed with 60 min restraint and trunk blood was collected for measuring hormone content by radioimmunoassay at the end of stress. All offspring of di/+ mothers had similar ACTH responses to restraint, while the di/di rats born to, and raised by di/di mothers showed reduced ACTH reactivity to restraint. The di/di rats showed elevated water turnover and required a daily cage cleaning every day, which meant frequent handling. To offset the role of handling, all rats had daily cage cleaning in the next series, but the results were the same as in the first series. To investigate whether lactation, the behaviour of the mother or some other factor during the pregnancy is responsible for the differences, pups from di/+ dams were raised by di/di foster mothers and vice versa. We found that the genotype of parental mother is more important than that of the foster mother. The corticosterone and prolactin elevation normally seen after acute stress was unchanged by family history, maternal or personal genotype. Furthermore, in studies with mutant animals, the rearing conditions should be controlled by the experimenter. In experiments with Brattleboro rats, the use of homozygous and heterozygous rats from the same litters of di/+ dams and di/di males is recommended. Our results suggest that vasopressin is not indispensable for ACTH release, and that the di/di genotype of the parental mother can decrease the stress reactivity of the di/di Brattleboro rats. [source] Laminar variation in neuronal viability and trophic dependence in neocortical slicesJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2001Mary M. Niblock Abstract Organotypic slices are used frequently in studies of central nervous system development and function because they provide excellent experimental access with significant preservation of cellular context and relationships. Within a slice, however, a variety of factors may cause individual classes of neurons to respond differently to the culture environment. Differences in deafferentation, cellular maturation, trophic dependence and ongoing naturally occurring cell death may produce changes in the neuronal population that are transparent to the experimenter but that could affect experimental results significantly. In this study, we examined the distribution and prevalence of cell death among neurons in each cortical layer in organotypic slices. In addition, we assessed the ability of several neurotrophic factors to ameliorate neuronal death in each cortical layer. Within the first 24 hr in culture, there was striking laminar variation in the extent of neuronal death in culture, which could not be accounted for by the pattern of programmed cell death in vivo. In addition, neurons in the six layers of the neocortex differed in the degree to which they could be rescued by neurotrophic factors. These data suggest that differential neuronal death and rescue are important considerations in studies utilizing organotypic slices and may represent particularly confounding variables in studies of effects of trophic factors in such preparations. J. Neurosci. Res. 65:455,462, 2001. © 2001 Wiley-Liss, Inc. [source] HIDDEN AND FALSE "PREFERENCES" ON THE STRUCTURED 9-POINT HEDONIC SCALEJOURNAL OF SENSORY STUDIES, Issue 6 2008XADENI VILLEGAS-RUIZ ABSTRACT An unspecified number of consumers who used a 9-point hedonic scale were frustrated because they could not express preferences for products with the same ratings. Accordingly, consumers were required to rate samples of yogurt on a 9-point structured hedonic scale. Consumers were able to express preference judgments because the testing was performed one-on-one with the experimenter. Thus, it was possible to determine the proportion of consumers who had given the same hedonic response to yogurts but still had preferences for one or other of the stimuli. Further testing, which included a pair of identical yogurts among the stimuli, allowed the proportion of preference and no preference responses elicited by identical stimuli to be determined in this context. Such data are useful as a control condition in preference testing, to assess the proportion of false preferences induced by the experimental conditions. PRACTICAL APPLICATIONS Consumer liking for various products is typically measured using the 9-point structured hedonic scale. Sometimes, consumers will give the same score to two products yet prefer one to the other. Such preferences are not recorded if the consumer is isolated from the experimenter and has no means of reporting them. However, the situation is easily rectified if the experimenter interacts one-on-one with the consumer. Sometimes, false preferences can be obtained from a hedonic scale. This tendency can be monitored by including identical stimuli in the measurements. The present study investigated the extent of such problems so that methods could be devised to address the problem. [source] Friction evaluation of elastomers in lubricated contactLUBRICATION SCIENCE, Issue 10 2009Gregory F. Simmons Abstract Friction testing of elastomers in lubricated contact is discussed with a focus on developing experimental arrangements that can produce worthwhile results. Practical issues unique to elastomers are covered as well as their solutions, including contact mechanics, material response to loading, contact edges, oil absorption, cleaning and specimen geometry. A critique of reciprocating laboratory testing machines, including high-frequency short stroke and low-frequency long stroke friction and wear machines, is conducted for their usefulness, as is critical analysis of a wide variety of specimen configurations with the aim of helping the laboratory experimenter to overcome many of the pitfalls associated with testing of elastomers in lubricated conditions. Results from experiments using various testing arrangements are analysed, and it is found that the synthetic ester and mineral oil used produced similar results. Copyright © 2009 John Wiley & Sons, Ltd. [source] Probabilistic cross-link analysis and experiment planning for high-throughput elucidation of protein structurePROTEIN SCIENCE, Issue 12 2004Xiaoduan Ye Abstract Emerging high-throughput techniques for the characterization of protein and protein-complex structures yield noisy data with sparse information content, placing a significant burden on computation to properly interpret the experimental data. One such technique uses cross-linking (chemical or by cysteine oxidation) to confirm or select among proposed structural models (e.g., from fold recognition, ab initio prediction, or docking) by testing the consistency between cross-linking data and model geometry. This paper develops a probabilistic framework for analyzing the information content in cross-linking experiments, accounting for anticipated experimental error. This framework supports a mechanism for planning experiments to optimize the information gained. We evaluate potential experiment plans using explicit trade-offs among key properties of practical importance: discriminability, coverage, balance, ambiguity, and cost. We devise a greedy algorithm that considers those properties and, from a large number of combinatorial possibilities, rapidly selects sets of experiments expected to discriminate pairs of models efficiently. In an application to residue-specific chemical cross-linking, we demonstrate the ability of our approach to plan experiments effectively involving combinations of cross-linkers and introduced mutations. We also describe an experiment plan for the bacteriophage , Tfa chaperone protein in which we plan dicysteine mutants for discriminating threading models by disulfide formation. Preliminary results from a subset of the planned experiments are consistent and demonstrate the practicality of planning. Our methods provide the experimenter with a valuable tool (available from the authors) for understanding and optimizing cross-linking experiments. [source] An investigation of listening and listening-while-reading accommodations on reading comprehension levels and rates in students with emotional disordersPSYCHOLOGY IN THE SCHOOLS, Issue 1 2005Andrea D. Hale Researchers used alternating treatment designs to investigate the effects of listening-while-reading (LWR) and listening interventions on comprehension levels and rates in four middle school students with emotional disorders. During LWR, students were instructed to read passages silently along with experimenters. During the listening condition, we did not give students a printed copy of the passage but merely instructed them to listen as an experimenter read the passages aloud. The control condition consisted of students reading passages silently. After each condition, students answered 10 comprehension questions without referring back to the printed passage. Although neither intervention resulted in comprehension levels consistently superior to those of the silent reading control condition, LWR and listening resulted in higher rates of comprehension than the silent reading control condition across all four students. However, listening appeared to improve reading comprehension rates in only two students. These results suggest that LWR may be an efficient procedure for enhancing comprehension across content areas with groups of students who have heterogeneous reading skills. The discussion focuses on future applied research with students with disabilities. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 39,51, 2005. [source] The effects of competition and competitiveness on cardiovascular activityPSYCHOPHYSIOLOGY, Issue 4 2001Lesley K. Harrison Cardiovascular activity was measured at resting baseline and in response to a car racing game, undertaken in competition or in cooperation with an experimenter, or individually. Competitiveness and win and goal orientations were assessed by questionnaire. Competition provoked increases in blood pressure and heart rate, and a significant shortening of the preejection period, an index of enhanced beta-adrenergic influences on the heart. The cooperation task was largely without effect, and although the solo task affected cardiovascular activity, it did so to a lesser extent and much less consistently than did the competition task. The three task conditions, then, were largely distinguishable by their capacity to activate beta-adrenergic processes. Participants high in competitiveness and desire to win showed higher blood pressure reactions and greater shortening of the preejection period to competition than those low in these characteristics. 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