Use of landmark configuration in pigeons and humans: II. Generality across search tasks.

Pigeons and humans searched for a goal that was hidden in varied locations within a search space. The goal location was fixed relative to an array of identical landmarks. Pigeons searched on the laboratory floor, and humans searched on a table top or an outdoor field. In Experiment 1, the goal was centered in a square array of 4 landmarks. When the spacing between landmarks was increased, humans searched in the middle of the expanded array, whereas pigeons searched in locations that preserved distance and direction to an individual landmark. In Experiment 2, the goal was centered between and a perpendicular distance away from 2 landmarks aligned in the left-right dimension. When landmark spacing was increased, humans, but not pigeons, shifted their searching away from the landmarks along the perpendicular axis. These results parallel those obtained in touch-screen tasks. Thus, pigeons and humans differ in how they use landmark configuration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

People,Places, Things: Web Presence for the Real World

The convergence of Web technology, wireless networks, and portable client devices provides new design opportunities for computer/communications systems. In the HP Labs' Cooltown project we have been exploring these opportunities through an infrastructure to support web presence for people, places and things. We put web servers into things like printers and put information into web servers about things like artwork; we group physically related things into places embodied in web servers. Using URLs for addressing, physical URL beaconing and sensing of URLs for discovery, and localized web servers for directories, we can create a location-aware but ubiquitous system to support nomadic users. On top of this infrastructure we can leverage Internet connectivity to support communications services. Web presence bridges the World Wide Web and the physical world we inhabit, providing a model for supporting nomadic users without a central control point.     

Evaluation of the rapid micromethod for ultracentrifugal separation of labeled plasma lipoproteins

The fractionations of plasma lipoproteins by 2 methods were compared to evaluate the rapid separation (Airfuge^®) method for lipoprotein distribution studies. When [¹²⁵I] labeled very low density, low density, and high density lipoproteins (VLDL, LDL, HDL), were separately centrifuged in buffers at d=1.006, 1.06 or 1.2 g/ml by the conventional ultracentrifuge and the Airfuge^®, separations of the fractions in the Airfuge^® were incomplete at both 5 C and 24 C, especially at d=1.006. [³H] Benzo (a)pyrene, when added to plasma, associates with the plasma proteins and lipoproteins, especially LDL. Compared to the standard techniques, the Airfuge^® method greatly overestimated its distribution into VLDL. The distribution of [³H] vitamin D₃ into the VLDL plus LDL fraction was also overestimated by the Airfuge^® procedure. It is concluded that caution should be observed in quantitative studies of lipoproteins in the Airfuge^®. A careful comparison of the distribution into or fractionation of lipoproteins by the 2 methods should always precede any quantitative determinations involving the Airfuge^®.     

Child health psychology.

[Correction Notice: An erratum for this article was reported in Vol 9(6) of Health Psychology (see record 2008-09119-001). The name of the author, Sharon Millstein, should be Susan Millstein.] The term child health psychology refers to the field of research on the behavioral aspects of children's health and illness. At this time we need to continue the work of the child health psychology special interest group and to draw into the Division of Health Psychology a much larger number of developmental psychologists, who need to be informed about the relevance of their scientific training to child health issues. We call the Division's attention and that of granting agencies such as the National Institute of Child Health and Human Development to the following high-priority child health research issues: adherence to pediatric medical regimens; child health promotion; family influences on child and adolescent health and disease; and stress and coping in childhood illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Optical wireless communication through fog in the presence of pointing errors

Terrestrial optical wireless communication (OWC) is emerging as a promising technology, which makes connectivity possible between high-rise buildings and metropolitan and intercity communication infrastructures. A light beam carries the information, which facilitates extremely high data rates. However, strict alignment between the transmitter and the receiver must be maintained at all times, and a pointing error can result in a total severance of the communication link. In addition, the presence of fog and haze in the propagation channel hampers OWC as the small water droplets scatter the propagating light. This causes attenuation due to the resultant spatial, angular, and temporal spread of the light signal. Furthermore, the ensuing low visibility may impede the operation of the tracking and pointing system so that pointing errors occur. We develop a model of light transmission through fogs of different optical densities and types using Monte Carlo simulations. Based on this model, the performance of OWC in fogs is evaluated at different wavelengths. The handicap of a transceiver pointing error is added to the model, and the paradoxically advantageous aspects of the transmission medium are exposed. The concept of a variable field of view receiver for narrow-beam OWC is studied, and the possibility of thus enhancing communication system performance through fog in an inexpensive and simple way is indicated.     

The Impact of Language Variety and Expertise on Perceptions of Online Political Discussions

An experimental design was employed in the investigation of the impact of two status cues, language style and source expertise, on people's perceptions of online political discussants and their intentions and motivations to participate in local online political discussion fora. Specifically, the colloquial form of Singapore English, known as Singlish, was manipulated, together with information about the expertise of a discussant, in a 2 × 2 between-subjects factorial design, with the discussion issue manipulated as a within-subjects variable. Eighty undergraduates, 42 male and 38 female, participated in the study. Overall, the results of this study provide very limited support for the significant effects of status cues on perceptions and participation. The implications of the results of this study for theories of computer-mediated communication and linguistics in the context of the Internet are discussed.     

Addressing the Ontology Acquisition Bottleneck Through Reverse Ontological Engineering

The use of ontologies in knowledge engineering arose as a solution to the difficulties associated with acquiring knowledge, commonly referred to as the knowledge acquisition bottleneck. The knowledge-level model represented in an ontology provides a much more structured and principled approach compared with earlier transfer-of-symbolic-knowledge approaches but brings with it a new problem, which can be termed the ontology-acquisition (and maintenance) bottleneck. Each ontological approach offers a different structure, different terms and different meanings for those terms. The unifying theme across approaches is the considerable effort associated with developing, validating and connecting ontologies. We propose an approach to engineering ontologies by retrospectively and automatically discovering them from existing data and knowledge sources in the organization. The method offered assists in the identification of similar and different terms and includes strategies for developing a shared ontology. The approach uses a human-centered, concept-based knowledge processing technique, known as formal concept analysis, to generate an ontology from examples. To assist classification of examples and to identify the salient features of the example, we use a rapid and incremental knowledge acquisition and representation technique, known as ripple-down rules. The method can be used as an alternative or complement to other approaches.     

Adsorption of pathogenic prion protein to quartz sand

Management responses to prion diseases of cattle, deer, and elk create a significant need for safe and effective disposal of infected carcasses and other materials. Furthermore, soil may contribute to the horizontal transmission of sheep scrapie and cervid chronic wasting disease by serving as an environmental reservoirforthe infectious agent. As an initial step toward understanding prion mobility in porous materials such as soil and landfilled waste, the influence of pH and ionic strength (l) on pathogenic prion protein (PrPsc) properties (viz. aggregation state and zeta-potential) and adsorption to quartz sand was investigated. The apparent average isoelectric point of PrPsc aggregates was 4.6. PrPsc aggregate size was largest between pH 4 and 6, and increased with increasing l at pH 7. Adsorption to quartz sand was maximal near the apparent isoelectric point of PrPsc aggregates and decreased as pH either declined or increased. PrPsc adsorption increased as suspension l increased, and reached an apparent plateau at l approximately 0.1 M. While trends with pH and l in PrPsc attachment to quartz surfaces were consistent with predictions based on Born-DLVO theory, non-DLVO forces appeared to contribute to adsorption at pH 7 and 9 (l = 10 mM). Our findings suggest that disposal strategies that elevate pH (e.g., burial in lime or fly ash), may increase PrPsc mobility. Similarly, PrPsc mobility may increase as a landfill ages, due to increases in pH and decreases in l of the leachate.     

Longitudinal associations between emotion regulation and depression in preadolescent girls: Moderation by the caregiving environment.

Identifying childhood precursors for depression has been challenging and yet important for understanding the rapid increase in the rate of depression among adolescent girls. This study examined the prospective relations of preadolescent girls’ emotion regulation and parenting style with depressive symptoms. Participants were 225 children and their biological mothers recruited from a larger longitudinal community study. Girls’ observed positive and negative emotion during a conflict resolution task with mothers, their ability to regulate sadness and anger, and their perception of parental acceptance and psychological control were assessed at age 9. Depressive symptoms were assessed by self-report at ages 9 and 10. The results indicated interactions between child emotion characteristics and parenting in predicting later depression. Specifically, low levels of positive emotion expression predicted higher levels of depressive symptoms in the context of moderate to high parental psychological control. Low levels of sadness regulation were predictive of high levels of depressive symptoms in the context of low to moderate parental acceptance. Findings from this study support the hypothesis that the prospective association between vulnerabilities in emotion regulation and depression are moderated by the caregiving environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)