CW and pulsed electrically detected magnetic resonance spectroscopy at 263 GHz/12 T on operating amorphous silicon solar cells

Here we describe a new high frequency/high field continuous wave and pulsed electrically detected magnetic resonance (CW EDMR and pEDMR) setup, operating at 263 GHz and resonance fields between 0 and 12 T. Spin dependent transport in illuminated hydrogenated amorphous silicon p-i-n solar cells at 5 K and 90 K was studied by in operando 263 GHz CW and pEDMR alongside with complementary X-band CW EDMR. Benefiting from the superior resolution at 263 GHz, we were able to better resolve EDMR signals originating from spin dependent hopping and recombination processes. 5 K EDMR spectra were found to be dominated by conduction and valence band tale states involved in spin dependent hopping, with additional contributions from triplet exciton states. 90 K EDMR spectra could be assigned to spin pair recombination involving conduction band tail states and dangling bonds as dominating spin dependent transport process, with additional contributions from valence band tail and triplet exciton states.Comment: 8 pages, 4 figure

Performance Pay and Multidimensional Sorting - Productivity, Preferences and Gender

This paper studies the impact of incentives on worker self-selection in a controlled laboratory experiment. Subjects face the choice between a fixed and a variable payment scheme. Depending on the treatment, the variable payment is a piece rate, a tournament or a revenue-sharing scheme. We find that output is higher in the variable pay schemes (piece rate, tournament, and revenue sharing) compared to the fixed payment scheme. This difference is largely driven by productivity sorting. In addition personal attitudes such as willingness to take risks and relative self-assessment as well as gender affect the sorting decision in a systematic way. Moreover, self-reported effort is significantly higher in all variable pay conditions than in the fixed wage condition. Our lab findings are supported by an additional analysis using data from a large and representative sample. In sum, our findings underline the importance of multi-dimensional sorting, i.e., the tendency for different incentive schemes to systematically attract people with different individual characteristics

Pretend Play and Creativity in Preschool-Aged Children: Associations and Brief Intervention

Cognitive and affective processes in play have related to measures of creativity in school-aged children. In a previous examination of these play processes in preschool-aged children with the Affect in Play Scale-Preschool version, cognitive and affective play processes related to divergent thinking. One goal of the current study was to replicate this finding and examine the relationship between pretend play and storytelling creativity in preschoolers. A second goal was to test the effectiveness of a brief play intervention. Adult-led play interventions have effectively improved play skills and related developmental skills for children with documented play deficits. However, there is a need for an empirically-based, brief play intervention for typically developing preschool-aged children. A pilot study found medium to large effect sizes for increased play skills for an intervention with preschool-aged children and their parents. The current study aimed to examine the effectiveness of the intervention without parent involvement. Forty-one typically developing children (ages 4-6 years) participated. Pretend play, divergent thinking, and creative storytelling were assessed at baseline and outcome. Children were randomly assigned to the play skills intervention, which received three 20-30 minute individual play sessions, or the active control. At baseline, results were that cognitive and affective play processes related to divergent thinking and creative storytelling. The play intervention did not significantly improve pretend play skills or creativity in the intervention group compared to the control group. Reasons for the nonsignfiicant findings for the intervention, suggestions for future refinement of the intervention, and implications for childhood development are discussed

Research Notes: Performance of lines from four generations of a backcrossing program involving Glycine max and G. soja

We are interested in the possibility of using Glycine soja as a source of genes for improving cultivars of Glycine max. However, some characteristics in G. soja , such as low yield, vining, l odging, shattering, non-defoliation at maturity, poor seed quality, and non-yellow seed coat color are not acceptable in a cultivar. The purpose of our study is to explore the performance of these characters in lines derived from a backcrossing program in which G. soja is the donor parent

Revealed preferences in a sequential prisoners' dilemma: a horse-race between five utility functions

We experimentally investigate behavior and beliefs in a sequential prisoner’s dilemma. Each subject had to choose an action as first-mover and a conditional action as second-mover. All subjects also had to state their beliefs about others’ second-mover choices. We find that subjects’ beliefs about others’ choices are fairly accurate on average. Using the elicited beliefs, we compare the explanatory power of a few current models of social and moral preferences. The data show clear differences in explanatory power between the preference models, both without and with control for the number of free parameters. The best-performing models explain about 80% of observed behavior. We use the estimated preference parameters to identify biases in subjects’ expectations. We find a consensus bias (whereby subjects believe others behave like themselves) and a certain optimism (whereby subjects overestimate probabilities for favorable outcomes), the former being about twice as strong as the second

The resurrection of group selection as a theory of human cooperation

Two books edited by members of the MacArthur Norms and Preferences Network (an interdisciplinary group, mainly anthropologists and economists) are reviewed here. These books in large part reflect a renewed interest in group selection that has occurred among these researchers: they promote the theory that human cooperative behavior evolved via selective processes which favored biological and/or cultural group-level adaptations as opposed to individual-level adaptations. In support of this theory, an impressive collection of cross-cultural data are presented which suggest that participants in experimental economic games often do not behave as self-interested income maximizers; this lack of self-interest is regarded as evidence of group selection. In this review, problems with these data and with the theory are discussed. On the data side, it is argued that even if a behavior seems individually-maladaptive in a game context, there is no reason to believe that it would have been that way in ancestral contexts, since the environments of experimental games do not at all resemble those in which ancestral humans would have interacted cooperatively. And on the theory side, it is argued that it is premature to invoke group selection in order to explain human cooperation, because more parsimonious individual-level theories have not yet been exhausted. In summary, these books represent ambitious interdisciplinary contributions on an important topic, and they include unique and useful data; however, they do not make a convincing case that the evolution of human cooperation required group selection

Treatment of Sleep Problems in Young Children: A Case Series Report of a Cognitive-Behavioral Play Intervention

Sleep problems and bedtime resistance are common in young children. Treatment is critical because sleep problems typically persist, and insufficient sleep is related to worse outcomes. Current behavioral treatments do not work directly with the child to reduce anxiety and distress at bedtime. Cognitive-behavioral play therapy is a treatment approach designed to teach coping skills to young children by combining cognitive-behavioral therapy with pretend play, a developmentally-appropriate intervention mode. The current case series examined the effectiveness of adding a brief cognitive-behavioral play intervention (CBPI) to parent behavior management for young children with sleep difficulties. Four children (4-6 years) received three 20-30 minute individual sessions during which the child played out stories with an advanced graduate student therapist (first author, K.F.) about a child coping with sleep problems. Each child’s parent also received a 30-minute sleep information session. Three parents returned questionnaires post-treatment. As expected, all three parents reported improvements in their child’s sleep habits, sleep anxiety, and general fears. All three parents also reported a high level of satisfaction with the treatment. These preliminary results suggest that the CBPI may be effective for decreasing anxiety and child distress when added to behavioral treatment, thus increasing the breadth of treatment approaches available for young children with sleep problems. These results are promising, although a randomized study is needed to further refine the intervention and establish the efficacy of a CBPI for treatment of sleep problems in young children