Detecting and characterising returns in a pulsed ladar system

A new multi-spectral laser radar (ladar) system based on the time-correlated single photon counting, time-of-flight technique has been designed to detect and characterise distributed targets at ranges of several kilometres. The system uses six separated laser channels in the visible and near infrared part of the electromagnetic spectrum. The authors present a method to detect the numbers, positions, heights and shape parameters of returns from this system, used for range profiling and target classification. The algorithm has two principal stages: non-parametric bump hunting based on an analysis of the smoothed derivatives of the photon count histogram in scale space, and maximum likelihood estimation using Poisson statistics. The approach is demonstrated on simulated and real data from a multi-spectral ladar system, showing that the return parameters can be estimated to a high degree of accuracy.     

Correlates of osteopenia in patients with cystic fibrosis

The responses to heat shock in Tritrichomonas mobilensis, a squirrel monkey parasite and Tritrichomonas augusta, an amphibian trichomonad, were evaluated by means of metabolic labeling with [35S]methionine. Electrophoretically separated trichomonad proteins synthesized at different temperatures were visualized by autoradiography and the label incorporation quantitated by a trichloroacetic acid precipitation procedure. A considerable difference in thermotolerance between the two species was found as the protein synthesis reached a maximum at 41 C in T. mobilensis and 37 C in T. augusta. The latter tolerated temperature increases 13 C above normal cultivation temperatures as compared to only 4 C thermotolerance range above normal in T. mobilensis. Major heat shock proteins (Hsps) were expressed in both T. mobilensis (with apparent Mr 94, 72, and 58 kDa) and T. augusta (Mr 94, 70, and 56 kDa) as revealed by autoradiography. Western blot analysis with polyclonal antibody against DnaK of Escherichia coli showed the presence of antigenic Hsp70 homologs in both trichomonads. Similarly, a polyclonal antibody against Hsp60 with broad interspecies cross-reactivity detected Hsp60 homologs in both T. mobilensis and T. augusta. The anti-DnaK antibody cross-reacted with a T. mobilensis protein localized in Golgi apparatus as demonstrated by immunoelectron microscopy. Immunocytochemistry on trichomonad frozen sections revealed the presence of the Hsp60 homolog in light-microscopic granules corresponding to hydrogenosomes.     

Occupational burnout, tolerance for stress, and coping among nurses in rehabilitation units.

The relation of problem-solving confidence, perceived tolerance of stressors, and situation-specific coping efforts to occupational burnout was examined among 88 nurses in physical rehabilitation units. Participants completed measures of problem solving and burnout, and were administered a questionnaire that required them to list stressors encountered at work and their ability to tolerate this stressor. Participants were also asked to list their typical ways of coping with this stressor. Consistent with predictions, confidence in one's ability to handle problems and perceived tolerance were significantly predictive of lower burnout scores, regardless of time spent on the job. Of the coping variables, emotion-focused coping was significantly associated with higher burnout scores. Post-hoc analyses of self-reported coping activities indicated that some coping efforts (e.g., taking time off from work, confronting a supervisor) could be construed as symptoms of burnout, according to theoretical conceptualizations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identifiability as a deterrant to social loafing: Two cheering experiments.

Two experiments with 156 male undergraduates tested the extent to which the identifiability of one's individual output moderates social loafing—the reduction of individual efforts due to the social presence of others. In the 1st stage of Exp I, Ss were asked to produce noise either alone, in groups of 2 and 6, or in pseudogroups where Ss actually shouted alone but believed that 1 or 5 other people were shouting with them. As in previous research, Ss exerted less effort when they thought that they were shouting in groups than when they shouted alone. In the 2nd stage, the same Ss were led to believe that their outputs would be identifiable even when they cheered in groups. This manipulation eliminated social loafing. Exp II demonstrated that when individual outputs were always identifiable (even in groups), Ss consistently exerted high levels of effort, and if their outputs were never identifiable (even when alone), they consistently exerted low levels of effort across all group sizes. Results suggest that identifiability is an important mediator of social loafing. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of personal involvement: Thought-provoking implications for social loafing.

In previous research, the 2nd author and colleagues (see record 1980-30335-001) observed that individuals working together put out less effort than when they work alone; this phenomenon was termed social loafing (SL). Subsequent research by these authors (see record 1981-32831-001) suggested that SL arises, at least in part, because when participants work with others on tasks their individual outputs are lost in the crowd, and, thus, they can receive neither credit nor blame for their performance. The possibility that personal involvement in a task could moderate the SL effect was tested in the present experiment, which used a 2 (high/low involvement)?×?2 (high/low identifiability) factorial design across 3 replications with 224 undergraduates. The task involved thoughts generated in response to a counterattitudinal proposal. Replicating previous SL research, present results show that under conditions of low involvement, Ss whose outputs were identifiable worked harder than those whose outputs were pooled. However, when the task was personally involving, the SL effect was eliminated: Ss whose outputs were pooled worked as hard as those whose individual outputs could be identified. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparative study of interval and conventional training in thoroughbred racehorses

Eight horses with previous racing experience were used in a comparative study of training methods for Thoroughbred racehorses. They were randomly assigned to two groups of four horses each. One group was trained using an interval training method (IT) and the other using conventional training (CT) methods. Peak heart rates, heart rate recovery curves, peak plasma lactate levels, plasma lactate clearance rates and run times were used to evaluate differences in the training methods. Peak heart rates, heart rate recovery curves, and run times were not significantly different between the groups. However, higher lactate production and increased plasma lactate clearance by the IT group demonstrated an increased anaerobic capacity.     

NMR study of the transforming growth factor-alpha (TGF-alpha)-epidermal growth factor receptor complex. Visualization of human TGF-alpha binding determinants through nuclear Overhauser enhancement analysis

The study of human transforming growth factor-alpha (TGF-alpha) in complex with the epidermal growth factor (EGF) receptor extracellular domain has been undertaken in order to generate information on the interactions of these molecules. Analysis of 1H NMR transferred nuclear Overhauser enhancement data for titration of the ligand with the receptor has yielded specific data on the residues of the growth factor involved in contact with the larger protein. Significant increases and decreases in nuclear Overhauser enhancement cross-peak intensity occur upon complexation, and interpretation of these changes indicates that residues of the A- and C-loops of TGF-alpha form the major binding interface, while the B-loop provides a structural scaffold for this site. These results corroborate the conclusions from NMR relaxation studies (Hoyt, D. W., Harkins, R. N., Debanne, M. T., O'Connor-McCourt, M., and Sykes, B. D. (1994) Biochemistry 33, 15283-15292), which suggest that the C-terminal residues of the polypeptide are immobilized upon receptor binding, while the N terminus of the molecule retains considerable flexibility, and are consistent with structure-function studies of the TGF-alpha/EGF system indicating a multidomain binding model. These results give a visualization, for the first time, of native TGF-alpha in complex with the EGF receptor and generate a picture of the ligand-binding site based upon the intact molecule. This will undoubtedly be of utility in the structure-based design of TGF-alpha/EGF agonists and/or antagonists.     

Social loafing and group evaluation.

Recent work (e.g., S. Harkins; see PA, Vol 75:20027; K. Szymanski and Harkins; see PA, Vol 75:7410) has suggested that social loafing occurs because participants' outputs cannot be evaluated by the experimenter, by the coactors, or by the participants themselves. This analysis had focused on the output of the individual, but in loafing research, participants work together to produce a group product. However, in this prior work participants have been unable to make anything of this group product, because no standard of comparison has been made available. Several recent formulations (e.g., G. Goethals and J. Darley, 1987) have suggested that the potential for group evaluation could motivate performance. Testing this hypothesis in 2 experiments, 1 using an optimizing task and the other a maximizing task, we found that providing a standard that allowed the "group" to evaluate its performance eliminated the loafing effect. The implications of these findings for current theories of group evaluation are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parallel electrophoretic depletion, fractionation, concentration, and desalting of 96 complex biological samples for mass spectrometry

The preparation of complex biological samples for high-throughput mass spectrometric analyses remains a significant bottleneck, limiting advancement of the capabilities of mass spectrometry (MS) and ultimately limiting development of novel clinical assays. The removal of interfering species (e.g., salts, detergents, and buffers), concentration of dilute analytes, and the reduction of sample complexity are required in order to maximize the quality of resultant MS data. This study describes a novel sample preparation method that makes use of electrophoresis to prepare complex biological samples for high-throughput MS analysis. The method provides for integration of key sample preparation steps, including depletion, fractionation, desalting, and concentration. The prepared samples are captured onto a monolithic reversed-phase capture target that can be analyzed directly by a mass spectrometer. Up to 96 individual samples are simultaneously prepared for MS analysis in under 1 h. For standard proteins added to serum, this method provides femtomole level sensitivity and reproducible label-free detection (coefficient of variation <30%). This study demonstrates that this electrophoretic sample preparation system permits high-throughput sample preparation for mass spectrometric analysis of complex biological samples, such as serum, plasma, and tissue extracts.     

Social loafing and self-evaluation with a social standard.

Social loafing has been described as the phenomenon in which participants who work together generate less effort than do participants who work alone (e.g., Latané, Williams, & Harkins, 1979). Subsequent research (Harkins & Jackson, 1985; Williams, Harkins, & Latané, 1981) has shown that a particular aspect of this paradigm leads to the loafing effect. In those studies, the evaluation potential of the experimenter has been emphasized. However, when the experimenter could not evaluate individual outputs, neither could the participants evaluate themselves. In this study we tested the possibility that the opportunity for the participants to evaluate themselves would be sufficient to eliminate the loafing effect. In 2 experiments, the evaluation potential of the experimenter (experimenter evaluation vs. no experimenter evaluation) was crossed with the potential for self-evaluation (self-evaluation vs. no self-evaluation). Consistent with previous loafing research, the potential for evaluation by the experimenter was sufficient to increase motivation, whether participants could self-evaluate or not. However, when the experimenter could not evaluate the participants' outputs, the potential for self-evaluation reliably improved participant performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)