bluuebunny/crossref_metadata_2025_split huggingface dataset:
Introduction to the Topic on Modeling Spatial Cognition
Authors: Gunzelmann Glenn 
Published: October 2011

AbstractOur ability to process spatial information is fundamental for understanding and interacting with the environment, and it pervades other components of cognitive functioning from language to mathematics. Moreover, technological advances have produced new capabilities that have created research opportunities and astonishing applications. In this Topic on Modeling Spatial Cognition, research crossing a variety of disciplines and methodologies is described, all focused on developing models to represent the capacities and limitations of human spatial cognition.
Experimental investigation of shock metamorphic effects in a metapelitic granulite: The importance of shock impedance contrast between components
Authors: OGILVIE Paula , GIBSON Roger L. , REIMOLD W. Uwe , DEUTSCH Alexander , HORNEMANN Ulrich 
Published: October 2011

Abstract–Shock recovery experiments were performed at 12.5, 25, 34, 40, and 56 GPa at 25 °C, and at 18 and 25 GPa at 400 °C, on a high‐grade, migmatitic, garnet‐cordierite metapelite from the Etivé aureole, Scotland. Objectives for this study were to (1) characterize shock effects in a complex polymineralic rock with a significant proportion of hydrous ferromagnesian minerals, both as a function of variable shock pressure and preshock temperature, and (2) to explore the effects of shock impedance contrast between component minerals on the respective abundances and distribution of these features. At any shock pressure, the order of decreasing intensity of shock metamorphic effects in component phases is: cordierite (Crd)→biotite (Bt)→plagioclase (Pl)→K‐feldspar (Kfs)→quartz (Qtz)→garnet (Grt)→orthopyroxene (Opx). Samples shocked to pressures below 40 GPa (25 °C) were typically characterized by marked heterogeneous distribution of shock effects on both intragranular and intergranular scales. Shock heterogeneity is mainly attributed to shock impedance contrast between contiguous phases, and manifests as shock amplification locally where shock impedance contrast is greatest, and shock suppression where impedance contrast is least. The heterogeneous distribution of shock metamorphic effects in both experiments and natural rocks is a signature of extreme disequilibrium at the submillimeter scale. The heterogeneous distribution of shock metamorphic effects mitigates against the use of shock effects in minerals exclusively as regional shock pressure barometers, and ought to be augmented by additional constraints on shock pressure from numerical models.
Testing an empathy model of guest‐directed citizenship and counterproductive behaviours in the hospitality industry: Findings from three hotels
Authors: Ho Violet T. , Gupta Naina 
Published: October 2011

This research proposes and tests an empathy model of guest‐directed discretionary behaviours (i.e., citizenship and counterproductive behaviours) using two studies conducted in three hotels. Building on the two‐stage model of empathic mediation, we examined the mediating role of empathic concern in the relationship between perspective taking and both forms of discretionary behaviours in Study 1. Support for this mediated model was found in relation to citizenship behaviours but not for counterproductive behaviours. Study 2 was conducted to extend these findings using peer reports of discretionary behaviours, and to apply an interactional psychology perspective to predict guest‐directed counterproductive behaviours. We drew upon trait activation theory to highlight the importance of situational triggers, in the form of interpersonal injustice from guests, in moderating the relationship between perspective taking and counterproductive behaviours, mediated through empathic concern. We found support for the hypothesized moderated mediation effect, such that perspective taking inhibited counterproductive behaviours through empathic concern only when interpersonal injustice was high, but not when injustice was low. Replicating the results in Study 1, perspective taking also positively predicted peer‐reported citizenship behaviours, but this was not mediated by empathic concern. Research and practical implications from these findings are discussed.Practitioner Points
Highlights to organizations in the hospitality industry the importance of perspective taking in generating customer goodwill, through promoting employees' citizenship behaviours towards guests, and in reducing their counterproductive behaviours in instances of guest injustice.
Suggests ways in which organizations can develop employees' perspective taking, such as appointing mentors or role models, providing training programmes to help employees improve their interpersonal skills, and assessing job applicants' trait empathy as part of the selection process.
The Timoshenko Beam With a Moving Load
Authors: Steele C. R. 
Published: October 2011

Abstract
The problem of a semi-infinite Timoshenko beam of an elastic foundation with a step load moving from the supported end at a constant velocity is discussed. Asymptotic solutions are obtained for all ranges of load speed. The solution is shown to approach the “steady-state” solution, except for three speeds at which the steady state does not exist. Previous investigators have considered only the steady-state solution for the moving concentrated load and have indicated that the three speeds are “critical.” It is shown, however, that only the lowest speed is truly critical in that the response increases with time. For the load speed equal to either the shear or bar velocity, the transients due to the end condition never leave the vicinity of the load discontinuities, so a steady-state condition is never attained. However, the response is shown to be bounded in time for a distributed load. Thus the nonexistence of a steady state does not necessarily indicate a critical condition. Furthermore, the concentrated load solution is shown to have validity at speeds the magnitude of the sonic speeds only for loads of a concentration beyond the limitations of beam theory. Asymptotic results have also been obtained for the beam without a foundation. Since the procedure is similar for beams with, and without, a foundation, only the results are included to show a comparison with the numerical results previously obtained by Florence.
On Inextensional Vibrations of Thin Shells
Authors: Ross E. W. 
Published: October 2011

Abstract
In this paper the nonsymmetric, free, elastic vibrations of thin domes of revolution are studied. It is assumed that the frequency is low. The asymptotic approximations previously given by the writer are used to estimate the general solution to the shell vibration equations at low frequencies. Approximations for the low natural frequencies and modes are derived systematically under a variety of edge conditions. Low natural frequencies are found only when the edge conditions impose no forces tangent to the shell surface. When the edge is free (and only then) Rayleigh’s inextensional frequencies are recovered. For certain other edge conditions, new natural frequencies are found that are above Rayleigh’s frequencies but still low compared, e.g., with the lowest membrane frequency. The displacement modes associated with these new frequencies are mostly of inextensional type. The general results are applied to estimate these new frequencies for spherical domes.
Axially Symmetric Creep Buckling of Circular Cylindrical Shells in
Axial Compression
Authors: Hoff N. J. 
Published: October 2011

Abstract
The creep-buckling phenomenon of circular cylindrical shells subjected to axial compression is studied in the presence of initial imperfections when the creep strain rate is proportional to a power of the stress with the exponent greater than unity. A closed-form solution is obtained for the critical time; that is, for the finite time at which the analysis predicts the development of indefinitely large displacements.
Gyroscopic Drifts Associated With Rotational Vehicle
Vibrations
Authors: Wenglarz R. A. , Kane T. R. 
Published: October 2011

Abstract
Exact dynamical and kinematical equations governing motions of a two-degree-of-freedom gyroscope mounted on a moving vehicle are formulated. From these equations, a set of simpler ones is derived by taking advantage of a number of experimentally verifiable facts, and this set is solved for a vehicle performing oscillations of small amplitude about an axis having an arbitrary orientation. The validity of the resulting drift theory is established by comparing its predictions with those of digital computer solutions of the exact equations of motion, and formulas relating drift rates to system parameters are presented.
Symmetric Arc Solutions of ζ¨ =
ζn
Authors: Atkinson C. P. , Dhoopar B. L. 
Published: October 2011

Abstract
This paper, "Symmetric Arc Solutions of ζ¨ = ζn," presents periodic solutions of this differential equation relating the complex variable ζ(t) = u(t) + iv(t) and its second time derivative ζ¨ The solutions are called symmetric arc solutions since they form such arcs on the ζ = u + iv-plane. The solutions, ζ(t), are “complex modes” of coupled nonlinear differential equations in the complex variables z1 and z2. Symmetric arc solutions are presented for a range of n from n = 3 to n = 101. Approximate solutions are presented and compared with solutions generated by digital computer. Solutions are presented on the ζ-plane and in the time domain as u(t) and v(t).
Collapse of a Gas-Filled Spherical Cavity
Authors: Jahsman W. E. 
Published: October 2011

Abstract
The PLK coordinate perturbation technique [10] is used to obtain a solution to the problem of collapse of gas-filled spherical cavity in an infinite compressible liquid. The gas is assumed to undergo quasi-static adiabatic compression and the liquid equation of state is taken to follow the modified Tate form [11]. The approach was first outlined by Benjamin [9] and in the present paper expressions for cavity wall history and fluid pressure, density, and particle velocity are carried out in complete detail for the first three terms in the expansions. It is found that the solutions for the variables can all be written as products of functions which depend on only one of the perturbed coordinates. For the coordinate corresponding to outward traveling characteristics (first used by Whitham [12]), only two functions are required; they are associated with cavity wall position and with velocity and satisfy second-order ordinary differential equations which are readily solved by digital computer. For the remaining coordinate (perturbed radius) the functions are all polynomials. A numerical example is presented and curves of cavity wall position, pressure, and velocity histories are given for the period associated with collapse and rebound of the cavity. Results are compared with earlier work based on the Gilmore adaptation of the Kirkwood-Bethe formulation [8], and good agreement is found.
Automated temporal tracking and segmentation of lymphoma on serial CT examinations
Authors: Xu Jiajing , Greenspan Hayit , Napel Sandy , Rubin Daniel L. 
Published: October 2011

Purpose:It is challenging to reproducibly measure and compare cancer lesions on numerous follow‐up studies; the process is time‐consuming and error‐prone. In this paper, we show a method to automatically and reproducibly identify and segment abnormal lymph nodes in serial computed tomography (CT) exams.Methods:Our method leverages initial identification of enlarged (abnormal) lymph nodes in the baseline scan. We then identify an approximate region for the node in the follow‐up scans using nonrigid image registration. The baseline scan is also used to locate regions of normal, non‐nodal tissue surrounding the lymph node and to map them onto the follow‐up scans, in order to reduce the search space to locate the lymph node on the follow‐up scans. Adaptive region‐growing and clustering algorithms are then used to obtain the final contours for segmentation. We applied our method to 24 distinct enlarged lymph nodes at multiple time points from 14 patients. The scan at the earlier time point was used as the baseline scan to be used in evaluating the follow‐up scan, resulting in 70 total test cases (e.g., a series of scans obtained at 4 time points results in 3 test cases). For each of the 70 cases, a “reference standard” was obtained by manual segmentation by a radiologist. Assessment according to response evaluation criteria in solid tumors (RECIST) using our method agreed with RECIST assessments made using the reference standard segmentations in all test cases, and by calculating node overlap ratio and Hausdorff distance between the computer and radiologist‐generated contours.Results:Compared to the reference standard, our method made the correct RECIST assessment for all 70 cases. The average overlap ratio was 80.7 ± 9.7% s.d., and the average Hausdorff distance was 3.2 ± 1.8 mm s.d. The concordance correlation between automated and manual segmentations was 0.978 (95% confidence interval 0.962, 0.984). The 100% agreement in our sample between our method and the standard with regard to RECIST classification suggests that the true disagreement rate is no more than 6%.Conclusions:Our automated lymph node segmentation method achieves excellent overall segmentation performance and provides equivalent RECIST assessment. It potentially will be useful to streamline and improve cancer lesion measurement and tracking and to improve assessment of cancer treatment response.
Evaluation of Pharmacokinetic/Pharmacodynamic Relationships of PD-0162819, a Biotin Carboxylase Inhibitor Representing a New Class of Antibacterial Compounds, Using
In Vitro
Infection Models
Authors: Ogden Adam , Kuhn Michael , Dority Michael , Buist Susan , Mehrens Shawn , Zhu Tong , Xiao Deqing , Miller J. Richard , Hanna Debra 
Published: October 2011

ABSTRACT

The present study investigated the pharmacokinetic/pharmacodynamic (PK/PD) relationships of a prototype biotin carboxylase (BC) inhibitor, PD-0162819, against
Haemophilus influenzae
3113 in static concentration time-kill (SCTK) and one-compartment chemostat
in vitro
infection models.
H. influenzae
3113 was exposed to PD-0162819 concentrations of 0.5 to 16× the MIC (MIC = 0.125 μg/ml) and area-under-the-curve (AUC)/MIC ratios of 1 to 1,100 in SCTK and chemostat experiments, respectively. Serial samples were collected over 24 h. For efficacy driver analysis, a sigmoid maximum-effect (
E
max
) model was fitted to the relationship between bacterial density changes over 24 h and corresponding PK/PD indices. A semimechanistic PK/PD model describing the time course of bacterial growth and death was developed. The AUC/MIC ratio best explained efficacy (
r
2
= 0.95) compared to the peak drug concentration (
C
max
)/MIC ratio (
r
2
= 0.76) and time above the MIC (
T
>MIC) (
r
2
= 0.88). Static effects and 99.9% killing were achieved at AUC/MIC values of 500 and 600, respectively. For time course analysis, the net bacterial growth rate constant, maximum bacterial density, and maximum kill rate constant were similar in SCTK and chemostat studies, but PD-0162819 was more potent in SCTK than in the chemostat (50% effective concentration [EC
50
] = 0.046 versus 0.34 μg/ml). In conclusion, basic PK/PD relationships for PD-0162819 were established using
in vitro
dynamic systems. Although the bacterial growth parameters and maximum drug effects were similar in SCTK and the chemostat system, PD-0162819 appeared to be more potent in SCTK, illustrating the importance of understanding the differences in preclinical models. Additional studies are needed to determine the
in vivo
relevance of these results.
In Vitro
Analyses of the Effects of Heparin and Parabens on Candida albicans Biofilms and Planktonic Cells
Authors: Miceli Marisa H. , Bernardo Stella M. , Ku T. S. Neil , Walraven Carla , Lee Samuel A. 
Published: October 2011

ABSTRACT

Infections and thromboses are the most common complications associated with central venous catheters. Suggested strategies for prevention and management of these complications include the use of heparin-coated catheters, heparin locks, and antimicrobial lock therapy. However, the effects of heparin on
Candida albicans
biofilms and planktonic cells have not been previously studied. Therefore, we sought to determine the
in vitro
effect of a heparin sodium preparation (HP) on biofilms and planktonic cells of
C. albicans
. Because HP contains two preservatives, methyl paraben (MP) and propyl paraben (PP), these compounds and heparin sodium without preservatives (Pure-H) were also tested individually. The metabolic activity of the mature biofilm after treatment was assessed using XTT [2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] reduction and microscopy. Pure-H, MP, and PP caused up to 75, 85, and 60% reductions of metabolic activity of the mature preformed
C. albicans
biofilms, respectively. Maximal efficacy against the mature biofilm was observed with HP (up to 90%) compared to the individual compounds (
P
< 0.0001). Pure-H, MP, and PP each inhibited
C. albicans
biofilm formation up to 90%. A complete inhibition of biofilm formation was observed with HP at 5,000 U/ml and higher. When tested against planktonic cells, each compound inhibited growth in a dose-dependent manner. These data indicated that HP, MP, PP, and Pure-H have
in vitro
antifungal activity against
C. albicans
mature biofilms, formation of biofilms, and planktonic cells. Investigation of high-dose heparin-based strategies (e.g., heparin locks) in combination with traditional antifungal agents for the treatment and/or prevention of
C. albicans
biofilms is warranted.
Pharmacokinetic Evaluation of the Penetration of Antituberculosis Agents in Rabbit Pulmonary Lesions
Authors: Kjellsson Maria C. , Via Laura E. , Goh Anne , Weiner Danielle , Low Kang Min , Kern Steven , Pillai Goonaseelan , Barry Clifton E. , Dartois Véronique 
Published: October 2011

ABSTRACT

Standard antituberculosis (anti-TB) therapy requires the use of multiple drugs for a minimum of 6 months, with variable outcomes that are influenced by a number of microbiological, pathological, and clinical factors. This is despite the availability of antibiotics that have good activity against
Mycobacterium tuberculosis in vitro
and favorable pharmacokinetic profiles in plasma. However, little is known about the distribution of widely used antituberculous agents in the pulmonary lesions where the pathogen resides. The rabbit model of TB infection was used to explore the hypothesis that standard drugs have various abilities to penetrate lung tissue and lesions and that adequate drug levels are not consistently reached at the site of infection. Using noncompartmental and population pharmacokinetic approaches, we modeled the rate and extent of distribution of isoniazid, rifampin, pyrazinamide, and moxifloxacin in rabbit lung and lesions. Moxifloxacin reproducibly showed favorable partitioning into lung and granulomas, while the exposure of isoniazid, rifampin, and pyrazinamide in lesions was markedly lower than in plasma. The extent of penetration in lung and lesions followed different trends for each drug. All four agents distributed rapidly from plasma to tissue with equilibration half-lives of less than 1 min to an hour. The models adequately described the plasma concentrations and reasonably captured actual lesion concentrations. Though further refinement is needed to accurately predict the behavior of these drugs in human subjects, our results enable the integration of lesion-specific pharmacokinetic-pharmacodynamic (PK-PD) indices in clinical trial simulations and in
in vitro
PK-PD studies with
M. tuberculosis
.
Phenotypic Changes in Artemisinin-Resistant Plasmodium falciparum Lines
In Vitro
: Evidence for Decreased Sensitivity to Dormancy and Growth Inhibition
Authors: Teuscher Franka , Chen Nanhua , Kyle Dennis E. , Gatton Michelle L. , Cheng Qin 
Published: October 2011

ABSTRACT

The appearance of
Plasmodium falciparum
parasites with decreased
in vivo
sensitivity but no measurable
in vitro
resistance to artemisinin has raised the urgent need to characterize the artemisinin resistance phenotype. Changes in the temporary growth arrest (dormancy) profile of parasites may be one aspect of this phenotype. In this study, we investigated the link between dormancy and resistance, using artelinic acid (AL)-resistant parasites. Our results demonstrate that the AL resistance phenotype has (i) decreased sensitivity of mature-stage parasites, (ii) decreased sensitivity of the ring stage to the induction of dormancy, and (iii) a faster recovery from dormancy.
Composition and Localization of Treponema denticola Outer Membrane Complexes
Authors: Godovikova Valentina , Goetting-Minesky M. Paula , Fenno J. Christopher 
Published: October 2011

ABSTRACTTheTreponema denticolaouter membrane lipoprotein-protease complex (dentilisin) contributes to periodontal disease by degrading extracellular matrix components and disrupting intercellular host signaling pathways. We recently demonstrated thatprcB, located upstream of and cotranscribed withprcAandprtP, encodes a 22-kDa lipoprotein that interacts with PrtP and is required for its activity. Here we further characterize products of the protease locus and their roles in expression, formation, and localization of outer membrane complexes. PrcB migrates in native gels as part of a >400-kDa complex that includes PrtP and PrcA, as well as the major outer sheath protein Msp. PrcB is detectable as a minor constituent of the purified active protease complex, which was previously reported to consist of only PrtP and auxiliary polypeptides PrcA1 and PrcA2. Though it lacks the canonical ribosome binding site present upstream of bothprcAandprtP, PrcB is present at levels similar to those of PrtP in whole-cell extracts. Immunofluorescence microscopy demonstrated cell surface exposure of the mature forms of PrtP, PrcA1, PrcB, and Msp. The 16-kDa N-terminal acylated fragment of PrtP (predicted to be released during activation of PrtP) was present in cell extracts but was detected neither in the purified active protease complex nor on the cell surface. PrcA2, detectable on the surface of Msp-deficient cells but not that of wild-type cells, coimmunoprecipitated with Msp. Our results indicate that PrcB is a component of the outer membrane lipoprotein protease complex and that Msp and PrcA2 interaction may mediate formation of a very-high-molecular-weight outer membrane complex.