Isotype-specific antibody responses to foot-and-mouth disease virus in sera and secretions of "carrier' and "non-carrier' cattle

Isotype-specific antibody responses to foot-and-mouth disease virus (FMDV) were measured in the sera and upper respiratory tract secretions of vaccinated and susceptible cattle challenged with FMDV by direct contact or by intranasal inoculation. A comparison was made between cattle that eliminated FMDV and those that developed and maintained a persistent infection. Serological and mucosal antibody responses were detected in all animals after challenge. IgA and IgM were detected before the development of IgG1 and IgG2 responses. IgM was not detected in vaccinated cattle. Challenge with FMDV elicited a prolonged biphasic secretory antibody response in FMDV "carrier' animals only. The response was detected as FMDV-specific IgA in both mucosal secretions and serum samples, which gained statistical significance (P < 0.05) by 5 weeks after challenge. This observation could represent the basis of a test to differentiate vaccinated and/or recovered convalescent cattle from FMDV "carriers'.     

Towards Focused Plan Monitoring: A Technique and an Application to Mobile Robots

Until recently, techniques for AI plan generation relied on highly restrictive assumptions that were almost always violated in real-world environments; consequently, robot designers adopted reactive architectures and avoided AI planning techniques. Some recent research efforts have focused on obviating such assumptions by developing techniques that enable the generation and execution of plans in dynamic, uncertain environments. In this paper, we discuss one such technique, rationale-based monitoring, originally introduced by Veloso, Pollack, and Cox (Proceedings for the Fourth International Conference on AI Planning Systems, Pittsburgh, PA, 1998, pp. 171–179) and we describe our use of it in a simple mobile robot environment. We review the original approach, describe how it can be adapted for a causal-link planner, and provide experimental results demonstrating that it can lead to improved plans without consuming excessive overhead. We also describe our use of rationale-based monitoring in a mobile robot office-assistant project currently in progress.     

Weaving patterns of lines and line segments in space

Aweaving W is a simple arrangement of lines (or line segments) in the plane together with a binary relation specifying which line is above the other. A system of lines (or line segments) in 3-space is called arealization ofW, if its projection into the plane isW and the above-below relations between the lines respect the specifications. Two weavings are equivalent if the underlying arrangements of lines are combinatorially equivalent and the above-below relations are the same. An equivalence class of weavings is said to be aweaving pattern. A weaving pattern isrealizable if at least one element of the equivalence class has a three-dimensional realization. A weaving (pattern)W is calledperfect if, along each line (line segment) ofW, the lines intersecting it are alternately above and below. We prove that (i) a perfect weaving pattern ofn lines is realizable if and only ifn 3, (ii) a perfect m byn weaving pattern of line segments (in a grid-like fashion) is realizable if and only if min(m, n) 3, (iii) ifn is sufficiently large, then almost all weaving patterns ofn lines are nonrealizable.Jànos Pach has been supported in part by Hungarian NFSR Grant 1812, NSF Grant CCR-8901484, and the Center for Discrete Mathematics and Theoretical Computer Science (DIMACS), a National Science Foundation Science and Technology Center, under NSF Grant STC88-09648. Richard Pollack has been supported in part by NSA Grant MDA904-89-H-2030, NSF Grants DMS-85-01947 and CCR-8901484, and DIMACS. Emo Welzl has been supported in part by the ESPRIT II Basic Research Actions Program of the EC under Contract No. 3075 (project ALCOM) and DIMACS.     

Selective isolation of reversible cold sensitive variants from Chinese hamster ovary cell cultures

The fine structure and cellular associations of the large pigment cells (LPC's) of the compound eye of the house fly were studied with high voltage and conventional electron microscopy. Depending on the sector of the compound eye, the facets are either rectangular or hexagonal. The underside of each facet has indentations exactly aligned with those on top into which inserts an angulated sleeve of LPC's. Under the rectangular lens facet 6 or 8 small compact (in cross section) LPC's join four elongate LPC's. Clusters of compact cells alternate in this ring with elongate ones. Compact cells compress together and become quadrangular (in cross section) several microns below their insertion into the lens and form "building block" corners while elongate cells form "side rails" for the rectangular type of distal pseudocone enclosure. Beneath hexagonal facets all LPC's are rather elongate with out corner cells. In both facet types LPC's enclose the pseudocone for a longitudinal distance of 4 mum and then are displaced as bordering cells by a sleeve of two corneal pigment cells (CPC's), each of which encloses half of the proximal pseudocone. For the following 6 mum of longitudinal distance these concentric sleeves of CPC's and LPC's form a double layer around the pseudocone. At about 10 mum below lens base the two sleeves separate; LPC's become attenuated and extend cable-like to the basement membrane and CPC's enclose the proximal pseudocone, Semper cells and distal retinula. The junction between lens and LPC's has critical structural value in that (1) this is the sole anchorage to the lens by the lengthy remainder of the ommatidium, and (2) LPC's enclose the semiliquid pseudocone in the most distal portion of the pseudocone. In addition to vertical support, the LPC's send out numerous lateral processes that make structural contact among themselves, with the corneal pigment cells and the photoreceptor cells. The structural features of this array are discussed relative to possible physiological roles.     

Supportive friendships moderate the association between stressful life events and sexual risk taking among African American adolescents.

Objective: This study examined whether uncontrollable stressful life events were associated with sexual risk taking among adolescents across a 1-year period, and whether supportive friendships modified associations. Design: Participants were 159 sexually active African American adolescents (57% male; mean age [SD] = 17.0 [1.5] years at baseline). Participants were recruited for in-person interviews through random digit dialing in one inner-city neighborhood characterized by high rates of poverty and crime relative to the surrounding city. Main Outcome Measures: Dependent variables included substance use before sexual activity and inconsistent condom use. Results: Among adolescents who reported low levels of supportive friendships, uncontrollable stressors were associated with greater levels of sexual risk taking over time. In contrast, uncontrollable stressors were not associated with sexual risk taking among adolescents who reported high social support from friends; risk taking was typically moderate to high among these adolescents. Conclusion: Different processes may explain sexual risk taking among adolescents with varying levels of social support from friends. Adolescents with low support may be prone to engagement in health risk behavior as a stress response, while adolescents with high support may engage in risk behavior primarily due to peer socialization of risk. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A psychobiocultural model of orthostatic panic among Cambodian refugees: Flashbacks, catastrophic cognitions, and reduced orthostatic blood-pressure response.

This paper investigates cognitive and physiological precursors of orthostatic panic (OP), that is, panic upon standing, which is a key complaint among traumatized Cambodian refugees. Prior research links OP to hypotension (lower blood pressure) and catastrophic cognitions. A clinical sample of 102 Cambodian refugees were assessed for posttraumatic stress disorder (PTSD), recent OP attacks, and anticipatory anxiety before engaging in an orthostatic challenge (OC) task during which they were monitored for blood pressure. After the task, they were assessed for OC-induced culture-related catastrophic cognitions, flashbacks, and panic attacks. We found that participants with recent OP (n = 60) had more PTSD, greater anticipatory anxiety before the OC, a larger drop in systolic blood pressure during the OC, more OC-induced catastrophic cognitions and flashbacks, and more severe OC-induced panic attack symptoms. Regression models showed that the severity of OC-induced panic symptoms was predicted by the magnitude of SBP drop and mediated by more severe catastrophic cognitions and flashbacks. Implications of the findings for cross-cultural psychopathology research and the treatment of both panic and PTSD in Cambodian refugees are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Structurally related peptide agonist, partial agonist, and antagonist occupy a similar binding pocket within the cholecystokinin receptor. Rapid analysis using fluorescent photoaffinity labeling probes and capillary electrophoresis

The molecular basis of ligand binding to receptors provides important insights for drug development. Here, we explore domains of the cholecystokinin (CCK) receptor that are critical for ligand binding, using a novel series of fluorescent photolabile probes, receptor proteolysis, and rapid high resolution separation of peptide fragments by capillary electrophoresis. Each probe incorporated the same fluorophore and a photolabile p-benzoylphenylalanine at the amino terminus of the pharmacophoric domain (residue 24 of CCK-33) of CCK analogues representing full agonist, partial agonist, and antagonist of this receptor. Each was used to label the CCK receptor expressed on Chinese hamster ovary-CCKR cells, with the labeled domain then released by cyanogen bromide cleavage. Capillary electrophoresis with laser-induced fluorescence detection achieved an on-capillary mass sensitivity of 1.6 attomoles (10(-18) mol), with an excellent signal-to-noise ratio. Each of the biologically divergent, but structurally similar probes saturably and specifically labeled the same receptor domain, consistent with conservation of "docking" determinants. This had an apparent mass of 2.9 kDa, most consistent with the first extracellular loop domain. An additional probe having its site of covalent attachment in a different region of the probe (residue 29 of CCK-33) labeled a distinct receptor fragment with differential migration on capillary electrophoresis (third extracellular loop). Identification of the specific receptor residue(s) covalently linked to the amino-terminal probes must await further fragmentation and sequence analysis.