Eye Tracking the Face in the Crowd Task: Why Are Angry Faces Found More Quickly?

Among a crowd of distractor faces, threatening or angry target faces are identified more quickly and accurately than are nonthreatening or happy target faces, a finding known as the “face in the crowd effect.” Two perceptual explanations of the effect have been proposed: (1) the “target orienting” hypothesis (i.e., threatening targets orient attention more quickly than do nonthreatening targets and (2) the “distractor processing” hypothesis (i.e., nonthreatening distractors paired with a threatening target are processed more efficiently than vice versa, leading to quicker detection of threatening targets). Using a task, with real faces and multiple identities, the current study replicated the face in the crowd effect and then, via eye tracking, found greater support for the target orienting hypothesis. Across both the classical search asymmetry paradigm (i.e., one happy target in a crowd of angry distractors vs. one angry target in a crowd of happy distractors) and the constant distractor paradigm (i.e., one happy target in a crowd of neutral distractors vs. one angry target in a crowd of neutral distractors), fewer distractors were fixated before first fixating angry targets relative to happy targets, with no difference in the processing efficiency of distractors. These results suggest that the face in the crowd effect on this task is supported to a greater degree by attentional patterns associated with properties of target rather those of the crowd.     

Functional data analysis for longitudinal data with informative observation times

In functional data analysis for longitudinal data, the observation process is typically assumed to be noninformative, which is often violated in real applications. Thus, methods that fail to account for the dependence between observation times and longitudinal outcomes may result in biased estimation. For longitudinal data with informative observation times, we find that under a general class of shared random effect models, a commonly used functional data method may lead to inconsistent model estimation while another functional data method results in consistent and even rate-optimal estimation. Indeed, we show that the mean function can be estimated appropriately via penalized splines and that the covariance function can be estimated appropriately via penalized tensor-product splines, both with specific choices of parameters. For the proposed method, theoretical results are provided, and simulation studies and a real data analysis are conducted to demonstrate its performance.     

TGF-β1 is an organizer of responses to neurodgeneration

TGF-β1 mRNA and protein were recently found to increase in animal brains after experimental lesions that cause local deafferentation or neuron death. Elevations of TGF-β1 mRNA after lesions are prominent in microglia but are also observed in neurons and astrocytes. Moreover, TGF-β1 mRNA autoinduces its own mRNA in the brain. These responses provide models for studying the increases of TGF-β1 protein observed in βA/amyloid-containing extracellular plaques of Alzheimer's disease (AD) and Down's syndrome (DS) and in brain cells of AIDS victims. Involvement of TGF-β1 in these human brain disorders is discussed in relation to the potent effects of TGF-β1 on wound healing and inflammatory responses in peripheral tissues. We hypothesize that TGF-β1 and possibly other TGF-β peptides have organizing roles in responses to neurodegeneration and brain injury that are similar to those observed in non-neural tissues. Work from many laboratories has shown that activities of TGF-β peptides on brain cells include chemotaxis, modification of extracellular matrix, and regulation of cytoskeletal gene expression and of neurotrophins. Similar activities of the TGF-β's are well established in other tissues.     

Vascular Cholinesterases and Choline Uptake in Isolated Rat Forebrain Microvessels: A Possible Link

The two parameters of the active [methyl-3H]choline uptake into isolated rat forebrain microvessels, Km and Vmax, were determined for 1-, 3-, 10-, and 24-month-old Charles River male rats and compared with the activities of the enzymes choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and butyrylcholinesterase (BuChE) in these microvessels over the same time course. The value of Km remained constant over the entire period, but that of Vmax increased from 8.5 +/- 1.0 to 80.6 +/- 16.4 nmol g-1 (mean +/- SEM) over the first 3 months of life. Over the same period, the increase in ChAT activity, from an initial value of 7.1 +/- 1.6 to 10.2 +/- 0.3 nmol g-1 min-1, was not proportional to that of choline uptake. Levels of BuChE activity (0.9-1.3 mumol g-1 min-1) were almost unchanged throughout the entire 24-month period, but those of AChE showed a steady and significant increase from 1 to 24 months, remaining relatively high at senescence (4.7 mumol g-1 min-1), when choline uptake had decreased to one-third of its optimal value. Selective inhibition of AChE with 1,5-bis(4-allyldimethylammonium-phenyl)pentan-3-one dibromide (0.5 microM) in unruptured capillaries from 3-month-old rats resulted in a decrease in Vmax of choline uptake from approximately 81 to 59 nmol g-1 min-1 or with 9-amino-1,2,3,4-tetrahydroacridine (10 microM) in capillaries from 2-month-old rats from approximately 30 to 15 nmol g-1 min-1. Selective inhibition of BuChE with tetraisopropyl pyrophosphoramide (100 microM) resulted in an increase in Vmax from approximately 81 to 96 nmol g-1 min-1. It is possible that the two vascular enzyme systems are coupled to a hypothetical endothelial choline transporter, but with an action opposite to each other.     

Difluoromethane, a New and Improved Inhibitor of Methanotrophy

Difluoromethane (HFC-32; DFM) is compared to acetylene and methyl fluoride as an inhibitor of methanotrophy in cultures and soils. DFM was found to be a reversible inhibitor of CH₄ oxidation by Methylococcus capsulatus (Bath). Consumption of CH₄ in soil was blocked by additions of low levels of DFM (0.03 kPa), and this inhibition was reversed by DFM removal. Although a small quantity of DFM was consumed during these incubations, its remaining concentration was sufficiently elevated to sustain inhibition. Methanogenesis in anaerobic soil slurries, including acetoclastic methanogenesis, was unaffected by levels of DFM which inhibit methanotrophy. Low levels of DFM (0.03 kPa) also inhibited nitrification and N₂O production by soils. DFM is proposed as an improved inhibitor of CH₄ oxidation over acetylene and/or methyl fluoride on the basis of its reversibility, its efficacy at low concentrations, its lack of inhibition of methanogenesis, and its low cost.     

In vitro studies on cell-mediated cytotoxicity by means of a terminal labeling technique.

A modification is described of the Takasugi-Klein assay for cell-mediated cytotoxicity, based on the measurement of ⁵¹Cr uptake by viable cells at the conclusion of effector-target cell interactions. Findings showing the applicability of this method to the quantitative determination of cell-mediated cytotoxicity against syngeneic solid tumors of mice are presented. It was found that repeated washing of splenocytes from donors with large tumors often elevated appreciably the cytotoxic capacity of the effector cells, and that washing of splenocytes from normal animals reduced their apparently nonspecific toxic effects.     

Analysis of pVU3695, a plasmid encoding glutathione-dependent formaldehyde dehydrogenase activity and formaldehyde resistance in the Escherichia coli VU3695 clinical strain

The formaldehyde resistance of Escherichia coli VU3695 is due to the expression of glutathione-dependent formaldehyde dehydrogenase (GSH-FDH) activity, which is encoded by the adhC gene located on the plasmid pVU3695. Conjugation of this plasmid to an unrelated PolA deficient strain of E. coli indicated that it encodes its own replication initiation protein and does not confer resistance to several other antimicrobial agents tested in this work. In addition, pVU3695 has homology with replicons that belong to the IncL/M plasmid incompatibility group, which are widely distributed among the Enterobacteriaceae. Curing of pVU3695 abolished the expression of formaldehyde resistance and the presence of a 46-kDa periplasmic protein immunologically related to GSH-FDH. However, the curing of pVU3695 reduced drastically but did not abolish the expression of a protein with similar electrophoretic motility, which was associated with the expression of GSH-FDH activity still present in the cytoplasm of the plasmidless derivative. The data demonstrate that E. coli VU3695 contains a chromosomal and a plasmid copy of adhC actively expressed, with the latter being involved in resistance to exogenous formaldehyde.