High-speed metal-semiconductor-metal photodetectors on InP:Fe

Metal-semiconductor-metal (MSM) photodetectors on semi-insulating InP:Fe with a lateral planar structure have been fabricated. Laterally structured photodiodes are formed with interdigitated contact fingers. The detectors exhibit low dark currents of about 10 nA, an impulse response of 26 ps FWHM (full-width of half-maximum), and an internal quantum efficiency of 80%, all at 10 V bias. An electrical cutoff frequency of 40 GHz for the packaged detectors is obtained from s -parameter measurements, demonstrating that the response time is not limited by the parasitic elements of the devices     

18F]fluoroethoxy-benzovesamicol, a PET radiotracer for the vesicular acetylcholine transporter and cholinergic synapses

CACO-2 BBE was used to determine the response of a gastrointestinal epithelium to tumor necrosis factor-alpha (TNF). Incubation of CACO-2 BBE with TNF did not produce any effect on transepithelial resistance (TER) within the first 6 hr but resulted in a 40-50% reduction in TER and a 30% decrease in 1SC (short circuit current) relative to time-matched control at 24 hr. The decrease in TER was sustained up to 1 week following treatment with TNF and was not associated with a significant increase in the transepithelial flux of [14C]-D-mannitol or the penetration of ruthenium red into the lateral intercellular space. Dilution potential and transepithelial 22Na+ flux studies demonstrated that TNF-treatment of CACO-2 BBE cell sheets increased the paracellular permeability of the epithelium to Na+ and Cl-. The increased transepithelial permeability did not associate with an increase in the incidence of apoptosis. However, there was a TNF-dependent increase in [3H]-thymidine labeling that was not accompanied by a change in DNA content of the cell sheet. The increase in transepithelial permeability was concluded to be across the tight junction because: (i) 1 mM apical amiloride reduced the basolateral to apical flux of 22Na+, and (ii) dilution potential studies revealed a bidirectionally increased permeability to both Na+ and Cl-. These data suggest that the increase in transepithelial permeability across TNF-treated CACO-2 BBE cell sheets arises from an alteration in the charge selectivity of the paracellular conductive pathway that is not accompanied by a change in its size selectivity.     

Intuition, affect, and personality: Unconscious coherence judgments and self-regulation of negative affect.

According to personality systems interaction theory, a negative mood was expected to reduce access to extended semantic networks and to reduce performance on intuitive judgments of coherence for participants who have an impaired ability to down-regulate negative affect (i.e., state-oriented participants). Consistent with expectations, state-oriented participants reporting higher levels of perseverating negative mood had a reduced discrimination between coherent and incoherent standard word triples (Study 1) and individually derived word triples describing persons (Study 2). Participants who are able to down-regulate negative affect (i.e., action-oriented participants) did not show this tendency. In addition, Study 2 revealed a dissociation between state orientation and Neuroticism that is discussed in terms of a functional difference between the two constructs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Categorization of speech by infants: Support for speech-sound prototypes.

This study tested 6-month-old infants' categorization of speech stimuli to investigate whether infants organize speech categories around "prototypes." In Experiment 1, infants first discriminated single "good" exemplars from two different vowel categories. They were then tested with 64 novel exemplars, 32 from each vowel category. The test stimuli varied in the degree to which they conformed to adult-defined prototypes of the two categories. The results showed that infants correctly sorted the novel stimuli over 90% of the time. In Experiment 2, we trained two groups of infants, one with a good (prototypical) exemplar from a vowel category and the other with a poor (nonprototypical) exemplar. Then we tested both groups with 16 novel exemplars from that same vowel category. Generalization to novel members of the category was significantly greater following exposure to the prototypical exemplar. Results are consistent with a model of speech perception that holds that young human infants organize vowel categories around prototypes. This may contribute to their seemingly efficient processing of speech information, even in the first half year of life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Real-Time Camera Tracking for Mobile Devices: The VisiTrack System

This paper presents VisiTrack, a novel approach for video based incremental tracking in real-time. The major objectives in the development of VisiTrack was to design or select algorithms that are well suited for embedded real-time computation. We had a special focus on latency reduction and storage minimization since the algorithms should run on mobile devices like PDAs with the appropriate extension, i.e. mainly a camera, in real-time. The image analysis, camera localization and feature position approximation of VisiTrack are explained in detail. The CV-SDF model, an extension of Synchronous Dataflow graphs (SDF), supporting the principles of linear processing and fine-grained pipelining was defined and applied for the design of all VisiTrack modules in order to fulfill real-time constraints and reduce system latency. Furthermore the camera localization and position approximation include mechanisms for minimization of errors that may arise for instance due to measurement inaccuracies. Current applications of VisiTrack in the augmented reality domain and robotic self localization show its good performance. However VisiTrack is not limited to these application domains.     

Intentional suppression of unwanted memories grows more difficult as we age.

People often encounter reminders to memories that they would prefer not to think about. When this happens, they often try to exclude the unwanted memory from awareness, a process that relies upon inhibitory control. We propose that the ability to regulate awareness of unwanted memories through inhibition declines with advancing age. In two experiments, we examined younger and older adults' ability to intentionally suppress retrieval when repeatedly confronted with reminders to an experience they were instructed to not think about. Older adults exhibited significantly less forgetting of the suppressed items compared to younger adults on a later independent probe test of recall, indicating that older adults failed to inhibit the to-be-avoided memories. These findings demonstrate that the ability to intentionally regulate conscious awareness of unwanted memories through inhibitory control declines with age, highlighting differences in memory control that may be of clinical relevance in the aftermath of unpleasant life events. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

When nonsense sounds happy or helpless: The Implicit Positive and Negative Affect Test (IPANAT).

This article introduces an instrument for the indirect assessment of positive and negative affect, the Implicit Positive and Negative Affect Test (IPANAT). This test draws on participant ratings of the extent to which artificial words subjectively convey various emotions. Factor analyses of these ratings yielded two independent factors that can be interpreted as implicit positive and negative affect. The corresponding scales show adequate internal consistency, test–retest reliability, stability (Study 1), and construct validity (Study 2). Studies 3 and 4 demonstrate that the IPANAT also measures state variance. Finally, Study 5 provides criterion-based validity by demonstrating that correlations between implicit affect and explicit affect are higher under conditions of spontaneous responding than under conditions of reflective responding to explicit affect scales. The present findings suggest that the IPANAT is a reliable and valid measure with a straightforward application procedure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)