216 research outputs found
I only have eyes for you: Ovulation redirects attention (but not memory) to attractive men
A number of studies have found a disjunction between women’s attention to, and memory for, handsome men. Although women pay initial attention to handsome men, they do not remember those men later. The present study examines how ovulation might differentially affect these attentional and memory processes. We found that women near ovulation increased their visual attention to attractive men. However, this increased visual attention did not translate into better memory. Discussion focuses on possible explanations, in the context of an emerging body of findings on disjunctions between attention to, and memory for, other people.National Institute of Mental Health (U.S.) (R01MH064734
Deducing transport properties of mobile vacancies from perovskite solar cell characteristics
The absorber layers in perovskite solar cells possess a high concentration of mobile ion vacancies. These vacancies undertake thermally activated hops between neighboring lattice sites. The mobile vacancy concentration N 0 is much higher and the activation energy E A for ion hops is much lower than is seen in most other semiconductors due to the inherent softness of perovskite materials. The timescale at which the internal electric field changes due to ion motion is determined by the vacancy diffusion coefficient D v and is similar to the timescale on which the external bias changes by a significant fraction of the open-circuit voltage at typical scan rates. Therefore, hysteresis is often observed in which the shape of the current-voltage, J-V, characteristic depends on the direction of the voltage sweep. There is also evidence that this defect migration plays a role in degradation. By employing a charge transport model of coupled ion-electron conduction in a perovskite solar cell, we show that E A for the ion species responsible for hysteresis can be obtained directly from measurements of the temperature variation of the scan-rate dependence of the short-circuit current and of the hysteresis factor H. This argument is validated by comparing E A deduced from measured J-V curves for four solar cell structures with density functional theory calculations. In two of these structures, the perovskite is MAPbI 3, where MA is methylammonium, CH 3 NH 3; the hole transport layer (HTL) is spiro (spiro-OMeTAD, 2,2 ′,7,7 ′- tetrakis[N,N-di(4-methoxyphenyl) amino]-9,9 ′-spirobifluorene) and the electron transport layer (ETL) is TiO 2 or SnO 2. For the third and fourth structures, the perovskite layer is FAPbI 3, where FA is formamidinium, HC (NH 2) 2, or MAPbBr 3, and in both cases, the HTL is spiro and the ETL is SnO 2. For all four structures, the hole and electron extracting electrodes are Au and fluorine doped tin oxide, respectively. We also use our model to predict how the scan rate dependence of the power conversion efficiency varies with E A, N 0, and parameters determining free charge recombination. </p
Signal Detection on the Battlefield: Priming Self-Protection vs. Revenge-Mindedness Differentially Modulates the Detection of Enemies and Allies
Detecting signs that someone is a member of a hostile outgroup can depend on very subtle cues. How do ecology-relevant motivational states affect such detections? This research investigated the detection of briefly-presented enemy (versus friend) insignias after participants were primed to be self-protective or revenge-minded. Despite being told to ignore the objectively nondiagnostic cues of ethnicity (Arab vs. Western/European), gender, and facial expressions of the targets, both priming manipulations enhanced biases to see Arab males as enemies. They also reduced the ability to detect ingroup enemies, even when these faces displayed angry expressions. These motivations had very different effects on accuracy, however, with self-protection enhancing overall accuracy and revenge-mindedness reducing it. These methods demonstrate the importance of considering how signal detection tasks that occur in motivationally-charged environments depart from results obtained in conventionally motivationally-inert laboratory settings.National Institute of Mental Health (U.S.) (Grant MH64734)U.S. Army Research Institute for the Behavioral and Social Sciences (Grant W74V8H-05-K-0003)National Science Foundation (U.S.) (Grant BCS-0642873
The green algal underground : evolutionary secrets of desert cells
Author Posting. © American Institute of Biological Sciences, 2008. This article is posted here by permission of American Institute of Biological Sciences for personal use, not for redistribution. The definitive version was published in BioScience 58 (2008): 114-122, doi:10.1641/B580206.Microscopic, unicellular, free-living green algae are found in desert microbiotic crusts worldwide. Although morphologically simple, green algae in desert crusts have recently been found to be extraordinarily diverse, with membership spanning five green algal classes and encompassing many taxa new to science. This overview explores this remarkable diversity and its potential to lead to new perspectives on the diversity and evolution of green plants. Molecular systematic and physiological data gathered from desert taxa demonstrate that these algae are long-term members of desert communities, not transient visitors from aquatic habitats. Variations in desiccation tolerance and photophysiology among these algae include diverse evolutionary innovations that developed under selective pressures in the desert. Combined with the single embryophyte lineage to which more familiar terrestrial green plants belong, multiple desert green algal lineages provide independent evolutionary units that may enhance understanding of the evolution and ecology of eukaryotic photosynthetic life on land.This work was supported by
grants from the National Aeronautics and Space Administration,
Exobiology Program (EXB02-0042-0054) to L. A. L.
and Z. G. C., from the National Science Foundation (DEB-
0529737) to L. A. L., and from the University of Connecticut
Research Foundation to Z. G. C
The Phanerozoic diversification of silica-cycling testate amoebae and its possible links to changes in terrestrial ecosystems
Cytogenetics of Mimosa bimucronata (DC.) O. Kuntze (Mimosoideae, Leguminosae): chromosome number, polysomaty and meiosis
Determinants of consumers’ intentions to share knowledge and intentions to purchase on s-commerce sites: incorporating attitudes toward persuasion attempts into a social exchange model
This research explores s-commerce users’ intentions to purchase and to share knowledge by incorporating ‘attitudes toward persuasion attempts,’ ‘ease of use,’ and ‘perceived usefulness’ into a social exchange theory model. A survey using an on-site purposive sampling technique was used to recruit the respondents, and an interception technique was used to approach the consumers. A total of 471 Korean consumers participated in this research. Based on 471 Korean social-commerce users, our results reveal that social exchange belief factors and a site’s usability affect user satisfaction, which subsequently affects users’ intentions to purchase and to share knowledge. In addition, attitudes toward persuasion attempts moderate the effect of satisfaction on users’ purchase intentions.
Keywords: social exchange theory, attitudes toward persuasion attempts, intention to share knowledge, social exchange belief
Law, Environment, and the “Nondismal” Social Sciences
Over the past 30 years, the influence of economics over the study of environmental law and policy has expanded considerably, becoming in the process the predominant framework for analyzing regulations that address pollution, natural resource use, and other environmental issues. This review seeks to complement the expansion of economic reasoning and methodology within the field of environmental law and policy by identifying insights to be gleaned from various “nondismal” social sciences. In particular, three areas of inquiry are highlighted as illustrative of interdisciplinary work that might help to complement law and economics and, in some cases, compensate for it: the study of how human individuals perceive, judge, and decide; the observation and interpretation of how knowledge schemes are created, used, and regulated; and the analysis of how states and other actors coordinate through international and global regulatory regimes. The hope is to provide some examples of how environmental law and policy research can be improved by deeper and more diverse engagement with social science
Stepwise evolution of Paleozoic tracheophytes from South China: contrasting leaf disparity and taxic diversity
During the late Paleozoic, vascular land plants (tracheophytes) diversified into a remarkable variety of morpho-
logical types, ranging from tiny, aphyllous, herbaceous forms to giant leafy trees. Leaf shape is a key determinant
of both function and structural diversity of plants, but relatively little is known about the tempo and mode of leaf
morphological diversification and its correlation with tracheophyte diversity and abiotic changes during this re-
markable macroevolutionary event, the greening of the continents. We use the extensive record of Paleozoic tra-
cheophytes from South China to explore models of morphological evolution in early land plants. Our findings
suggest that tracheophyte leaf disparity and diversity were decoupled, and that they were under different selec-
tive regimes. Two key phases in the evolution of South Chinese tracheophyte leaves can be recognized. In the first
phase, from Devonian to Mississippian, taxic diversity increased substantially, as did leaf disparity, at the same
time as they acquired novel features in their vascular systems, reproductive organs, and overall architecture.
The second phase, through the Carboniferous–Permian transition, saw recovery of wetland communities in
South China, associated with a further expansion of morphologies of simple leaves and an offset shift in
morphospace occupation by compound leaves. Comparison with Euramerica suggests that the floras from
South China were unique in several ways. The Late Devonian radiation of sphenophyllaleans contributed signif-
icantly to the expansion of leaf morphospace, such that the evolution of large laminate leaves in this group oc-
curred much earlier than those in Euramerica. The Pennsylvanian decrease in taxic richness had little effect on
the disparity of compound leaves. Finally, the distribution in morphospace of the Permian pecopterids,
gigantopterids, and equisetaleans occurred at the periphery of Carboniferous leaf morphospace
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