bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydromagnetic waves and instabilities in kappa distribution plasma
Authors: Basu B.
Published: May 2009

Stability properties of hydromagnetic waves (shear and compressional Alfven waves) in spatially homogeneous plasma are investigated when the equilibrium particle velocity distributions in both parallel and perpendicular directions (in reference to the ambient magnetic field) are modeled by kappa distributions. Analysis is presented for the limiting cases |ξα|⪡1 and |ξα|⪢1 for which solutions of the dispersion relations are analytically tractable. Here ξα(α=e,i) is the ratio of the wave phase speed and the electron (ion) thermal speed. Both low and high β (=plasma pressure/magnetic pressure) plasmas are considered. The distinguishing features of the hydromagnetic waves in kappa distribution plasma are (1) both Landau damping and transit-time damping rates are larger than those in Maxwellian plasma because of the enhanced high-energy tail of the kappa distribution and (2) density and temperature perturbations in response to the electromagnetic perturbations are different from those in Maxwellian plasma when |ξα|⪡1. Moreover, frequency of the oscillatory stable modes (e.g., kinetic shear Alfven wave) and excitation condition of the nonoscillatory (zero frequency) unstable modes (e.g., mirror instability) in kappa distribution plasma are also different from those in Maxwellian plasma. Quantitative estimates of the differences depend on the specific choice of the kappa distribution. For simplicity of notations, same spectral indices κ∥ and κ⊥ have been assumed for both electron and ion population. However, the analysis can be easily generalized to allow for different values of the spectral indices for the two charged populations.
The competition between the liquid-liquid dewetting and the liquid-solid dewetting
Authors: Xu Lin , Shi Tongfei , An Lijia
Published: May 2009

We investigate the dewetting behavior of the bilayer of air/PS/PMMA/silanized Si wafer and find the two competing dewetting pathways in the dewetting process. The upper layer dewets on the lower layer (dewetting pathway 1, the liquid-liquid dewetting) and the two layers rupture on the solid substrate (dewetting pathway 2, the liquid-solid dewetting). To the two competing dewetting pathways, the process of forming holes and the process of hole growth, influence their competing relation. In the process of forming holes, the time of forming holes is a main factor that influences their competing relation. During the process of hole growth, the dewetting velocity is a main factor that influences their competing relation. The liquid-liquid interfacial tension, the film thickness of the polymer, and the viscosity of the polymer are important factors that influence the time of forming holes and the dewetting velocity. When the liquid-liquid dewetting pathway and the liquid-solid dewetting pathway compete in the dewetting process, the competing relation can be controlled by changing the molecular weight of the polymer, the film thickness, and the annealing temperature. In addition, it is also found that the rim growth on the solid substrate is by a rolling mechanism in the process of hole growth.
Delay-induced multiple stochastic resonances on scale-free neuronal networks
Authors: Wang Qingyun , Perc Matjaž , Duan Zhisheng , Chen Guanrong
Published: May 2009

We study the effects of periodic subthreshold pacemaker activity and time-delayed coupling on stochastic resonance over scale-free neuronal networks. As the two extreme options, we introduce the pacemaker, respectively, to the neuron with the highest degree and to one of the neurons with the lowest degree within the network, but we also consider the case when all neurons are exposed to the periodic forcing. In the absence of delay, we show that an intermediate intensity of noise is able to optimally assist the pacemaker in imposing its rhythm on the whole ensemble, irrespective to its placing, thus providing evidences for stochastic resonance on the scale-free neuronal networks. Interestingly thereby, if the forcing in form of a periodic pulse train is introduced to all neurons forming the network, the stochastic resonance decreases as compared to the case when only a single neuron is paced. Moreover, we show that finite delays in coupling can significantly affect the stochastic resonance on scale-free neuronal networks. In particular, appropriately tuned delays can induce multiple stochastic resonances independently of the placing of the pacemaker, but they can also altogether destroy stochastic resonance. Delay-induced multiple stochastic resonances manifest as well-expressed maxima of the correlation measure, appearing at every multiple of the pacemaker period. We argue that fine-tuned delays and locally active pacemakers are vital for assuring optimal conditions for stochastic resonance on complex neuronal networks.
Doping induced anisotropic growth in C60
Authors: Wu Miao Miao , Sun Qiang , Wang Qian , Jena Puru , Kawazoe Yoshiyuki
Published: May 2009

Using density functional theory with generalized gradient approximation for exchange and correlation energy, we show that substitution of a Si atom at one of the C sites in C60 not only allows C59Si to have a hydrophobic head with a hydrophilic tail but also the Si atom acts as a seed for anisotropic growth of the heterofullerene. This is demonstrated by interacting C59Si with N7Sc and B8Si. The resulting complex structures exhibit enhanced electric dipole moments and anisotropy. Thus, doping induced anisotropic growth of nanostructures provides a novel route for the synthesis of bifunctional particles with atomic-level control on selectivity and diversity. These particles may have important applications in biomedical, solar, and display industry.
Displacement of the proton in hydrogen-bonded complexes of hydrogen fluoride by beryllium and magnesium ions
Authors: McDowell Sean A. C.
Published: May 2009

The displacement of the proton by a beryllium ion and by a magnesium ion from hydrogen-bonded complexes of hydrogen fluoride, of varying hydrogen bond strengths, was investigated theoretically using ab initio methods. Stable metal-containing species were obtained from all of the hydrogen-bonded complexes regardless of the strength of the hydrogen bond. It was found that the beryllium ion was energetically very effective in displacing the proton from hydrogen bonds, whereas the magnesium ion was unable to do so. The high stability of the beryllium-containing complexes is mainly due to the strong electrostatic bonding between the beryllium and fluoride atoms. This work supports the recent finding from a multidisciplinary bioinorganic study that beryllium displaces the proton in many strong hydrogen bonds.
High-reflectivity broadband distributed Bragg reflector lattice matched to ZnTe
Authors: Pacuski W. , Kruse C. , Figge S. , Hommel D.
Published: May 2009

We report on the realization of a high quality distributed Bragg reflector with both high and low refractive index layers lattice matched to ZnTe. Our structure is grown by molecular beam epitaxy and is based on binary compounds only. The high refractive index layer is made of ZnTe, while the low index material is made of a short period triple superlattice containing MgSe, MgTe, and ZnTe. The high refractive index step of Δn=0.5 in the structure results in a broad stop band and the reflectivity coefficient exceeding 99% for only 15 Bragg pairs.
Enhancement in the thermoelectric performance by Y substitution on SrSi2
Authors: Lue C. S. , Chou M. D. , Kaurav N. , Chung Y. T. , Kuo Y. K.
Published: May 2009

We report the results of the Y substitution in Sr1−xYxSi2 with x≤0.15 via measuring the temperature-dependent electrical resistivity, thermal conductivity, as well as Seebeck coefficient. Upon substituting Y onto the Sr sites, the electrical resistivity exhibit semiconducting behavior and the room-temperature electrical resistivity tends to reduce for x≤0.08. The thermal conductivity also decreases with increasing the Y content. Moreover, the Seebeck coefficient has a substantial increase and a maximum of about 220 μV/K at around 80 K has been found for x=0.08. These promising effects lead to a significant enhancement in the thermoelectric performance characterized by the figure-of-merit, ZT. A room-temperature ZT value of approximately 0.4 is thus achieved for Sr0.92Y0.08Si2, about one order of magnitude larger than that of stoichiometric SrSi2.
Schottky barrier lowering with the formation of crystalline Er silicide on n-Si upon thermal annealing
Authors: Reckinger Nicolas , Tang Xiaohui , Bayot Vincent , Yarekha Dmitri A. , Dubois Emmanuel , Godey Sylvie , Wallart Xavier , Larrieu Guilhem , Łaszcz Adam , Ratajczak Jacek , Jacques Pascal J. , Raskin Jean-Pierre
Published: May 2009

The evolution of the Schottky barrier height (SBH) of Er silicide contacts to n-Si is investigated as a function of the annealing temperature. The SBH is found to drop substantially from 0.43 eV for the as-deposited sample to reach 0.28 eV, its lowest value, at 450 °C. By x-ray diffraction, high resolution transmission electron microscopy, and x-ray photoelectron spectroscopy, the decrease in the SBH is shown to be associated with the progressive formation of crystalline ErSi2−x.
Energy-trapping mode in lateral-field-excited acoustic wave devices
Authors: Wang Wenyan , Zhang Chao , Zhang Zhitian , Ma Tingfeng , Feng Guanping
Published: May 2009

We have analyzed the energy-trapping phenomenon of the thickness-shear vibration in lateral-field-excited (LFE) acoustic wave devices based on elastic wave propagation theory and the cutoff frequency. The standard LFE device does not support the energy-trapping effect, which is significantly different from thickness-field-excited devices. However, energy trapping in LFE devices can be achieved by placing an additional mass-loading layer in the gap region between the two working electrodes. A 5 MHz energy-trapping LFE device is fabricated and tested. The experimental results are in close agreement with the theoretical analysis.
Surface acoustic wave mediated exciton dissociation in a ZnCdSe/LiNbO3 hybrid
Authors: Fuhrmann D. A. , Wixforth A. , Curran A. , Morrod J. K. , Prior K. A. , Warburton R. J. , Ebbecke J.
Published: May 2009

By making use of epitaxial lift-off, ZnCdSe quantum wells are transferred onto a LiNbO3 substrate in order to employ its enhanced piezoelectric properties. The photoluminescence emission of this hybrid structure is characterized and the influence of a surface acoustic wave on the free exciton and bound exciton emission is investigated. Finally, two counterpropagating surface acoustic waves are launched leading to a decrease in the acoustic wave mediated exciton dissociation.
Enhancement of multiferroic properties of Pb(Fe1/2Nb1/2)O3 thin films on SrRuO3 buffered SrTiO3 substrates
Authors: Yan Li , Zhao Xin , Li Jiefang , Viehland D.
Published: May 2009

We report multiferroic properties of Pb(Fe1/2Nb1/2)O3 (or PFN) epitaxial thin layers grown on (001), (110), and (111) SrTiO3 substrates with and without a SrRuO3 (SRO) buffer. Our findings are as follows: (i) the constraint stress on (001) substrates is more than ten times larger than those on (110) and (111); (ii) this large constraint stress induces higher piezoelectric constants, magnetic permeability and magnetization for (001) PFN compared with (110) and (111) layers; (iii) epitaxy distorts the structure of (001) PFN causing the films to be weakly ferromagnetic, whereas (110) films are antiferromagnetic; and (iv) a significant increase of the coercivity of (001) layers occurs due to clamping by a SRO buffer layer.
Revealing the uniaxial to biaxial nematic liquid crystal phase transition via distinctive electroconvection
Authors: Xiang Ying , Goodby J. W. , Görtz V. , Gleeson H. F.
Published: May 2009

Electroconvection (EC) phenomena are reported in the uniaxial and biaxial nematic phases of a bent-core liquid crystal. Two EC instabilities are observed. Prewavy_1, which exists only in the uniaxial phase, has stripes parallel to the rubbing direction, a periodicity of order of the device thickness, and an onset voltage that diverges near the uniaxial to biaxial transition. The prewavy_2 instability, characterized by stripes perpendicular to the rubbing direction and a periodicity of twice the device thickness, exists across the entire nematic regime. Our observations are explained through changes in the electrical conductivity anisotropy at the uniaxial to biaxial transition.
Dependence of domain wall structure for low field injection into magnetic nanowires
Authors: Kunz Andrew , Reiff Sarah C.
Published: May 2009

Micromagnetic simulation is used to model the injection of a domain wall into a magnetic nanowire with field strengths less than the so-called Walker field. This ensures fast, reliable motion of the wall [N. L. Schryer and L. R. Walker, J. Appl. Phys. 45, 5406 (1974)]. When the wire is located at the edge of a small injecting disk, a bias field used to control the orientation of the domain wall can reduce the pinning potential of the structure. The low field injection is explained by a simple model, which relies on the topological nature of a domain wall. The technique can quickly inject multiple domain walls with a known magnetic structure.
Size dependence of rutile TiO2 lattice parameters determined via simultaneous size, strain, and shape modeling
Authors: Kuznetsov Alexei Y. , Machado Rogério , Gomes Lincoln S. , Achete Carlos A. , Swamy Varghese , Muddle Barry C. , Prakapenka Vitali
Published: May 2009

Simultaneous crystal structure, microstructure, and morphology modeling with convolution-based profile fitting of angle-dispersive synchrotron x-ray diffraction data was applied to retrieve the size-dependent lattice changes in nanocrystalline rutile TiO2. The dominant prismatic crystallite morphology was adequately modeled using the parallelepiped geometry. As with anatase TiO2, opposing trends of decreasing c and increasing a parameter, as well as lattice expansion with decreasing average crystallite size were observed. A correlation between Ti vacancy abundance and lattice volume increase suggests a possible causative link.
Spin polarization of Fe4N thin films determined by point-contact Andreev reflection
Authors: Narahara A. , Ito K. , Suemasu T. , Takahashi Y. K. , Ranajikanth A. , Hono K.
Published: May 2009

The spin polarization of (100)-oriented γ′-Fe4N layers grown on MgO(001) substrates by molecular beam epitaxy was deduced from point contact Andreev reflection measurements, and the value was compared with that of α-Fe. The spin polarization (P) for γ′-Fe4N is approximately 0.59 at 7.8 K. This value is distinctly larger than that for α-Fe (P=0.49 at 7.8 K) measured with an identical setting. The mechanism of enhanced spin polarization in γ′-Fe4N is discussed.
Line Segments and Corners of Distractors are Equally Important in Causing Interference
Authors: Hluchanic Catherine , Kritikos Ada
Published: May 2009

In this series of studies we examine the importance of component features (line segments and corners) of a distractor in producing distractor interference. We postulated that corners are non-accidental features and therefore crucial components in the processing of distractors (Kritikos and Pavlis 2007, Experimental Brain Research183 159–170). We presented non-degraded or degraded (line segments or corners removed) distractors (line drawings of tools or musical instruments) simultaneously with a target, either at fixation or peripherally. Non-degraded as well as degraded distractors caused higher levels of interference (increased reaction times and a greater number of errors), particularly when presented at fixation, while non-degraded distractors caused greater interference than degraded. Contrary to expectation, however, there was no difference in the level of interference caused by lines-missing and corners-missing distractors, either at fixation or at periphery. Thus, we conclude that, where response to a complex object is required, both lines and corners are equally important components in the visual processing of distractor stimuli.
Modulation of Visually Evoked Movement Responses in Moving Virtual Environments
Authors: Reed-Jones Rebecca J , Vallis Lori Ann
Published: May 2009

Virtual-reality technology is being increasingly used to understand how humans perceive and act in the moving world around them. What is currently not clear is how virtual reality technology is perceived by human participants and what virtual scenes are effective in evoking movement responses to visual stimuli. We investigated the effect of virtual-scene context on human responses to a virtual visual perturbation. We hypothesised that exposure to a natural scene that matched the visual expectancies of the natural world would create a perceptual set towards presence, and thus visual guidance of body movement in a subsequently presented virtual scene. Results supported this hypothesis; responses to a virtual visual perturbation presented in an ambiguous virtual scene were increased when participants first viewed a scene that consisted of natural landmarks which provided ‘real-world’ visual motion cues. Further research in this area will provide a basis of knowledge for the effective use of this technology in the study of human movement responses.
The consequences of substance use among gay and bisexual men: A Consensual Qualitative Research analysis
Authors: Mullens Amy B. , Young Ross McD. , Hamernik Elisabeth , Dunne Michael
Published: May 2009

Background: Substance use is common among gay/bisexual men and is associated with significant health risks (e.g. HIV transmission). The consequences of substance use, across the range of substances commonly used, have received little attention. The purpose of this study is to map participant’s beliefs about the effects of substance use to inform prevention, health promotion and clinical interventions. Methods: Participants were interviewed about experiences regarding their substance use and recruited through medical and sexual health clinics. Data were collected though a consumer panel and individual interviews. Responses regarding perceived consequences of substance use were coded using Consensual Qualitative Research (CQR) methodology. Results: Most participants reported lifetime use of alcohol, cannabis, stimulants and amyl nitrite, and recent alcohol and cannabis use. A wide range of themes were identified regarding participant’s thoughts, emotions and behaviours (including sexual behaviours) secondary to substance use, including: cognitive functioning, mood, social interaction, physical effects, sexual activity, sexual risk-taking, perception of sexual experience, arousal, sensation, relaxation, disinhibition, energy/activity level and numbing. Analyses indicated several consequences were consistent across substance types (e.g. cognitive impairment, enhanced mood), whereas others were highly specific to a given substance (e.g. heightened arousal post amyl nitrite use). Conclusions: Prevention and interventions need to consider the variety of effects of substance use in tailoring effective education programs to reduce harms. A diversity of consequences appear to have direct and indirect impacts on decision-making, sexual activity and risk-taking. Findings lend support for the role of specific beliefs (e.g. expectancies) related to substance use on risk-related cognitions, emotions and behaviours.
Anal sex is a behavioural marker for laboratory-confirmed vaginal sexually transmissible infections and HIV-associated risk among African-American female adolescents
Authors: DiClemente Ralph J. , Wingood Gina M. , Crosby Richard A. , Salazar Laura F. , Head Sara , Rose Eve , Sales Jessica McDermott , Caliendo Angela M.
Published: May 2009

Background: African-American females are disproportionately affected by HIV and sexually transmissible infections (STIs). The prevalence of anal sex and its association with other sexual risk behaviours is understudied in this population. Methods: Participants were 715 African-American females, 15 to 21 years old, who had reported sexual activity in the previous 60 days. Data collection included an audiocomputer assisted self-interview (ACASI) and a self-collected vaginal swab specimen assayed using nucleic acid amplification tests to detect the presence of Chlamydia trachomatis and Neisseria gonorrhoeae, and real-time polymerase chain reaction assay to detect Trichomonas vaginalis. Results: Approximately 10.5% reported anal sex, at least once, during the 60 days before completing the computerised baseline assessment. The prevalence of any STI was significantly greater among adolescents reporting recent anal sex (40% tested positive for at least one of three laboratory-confirmed STIs) relative to those adolescents not reporting anal sex (27.5% STI prevalence). Of the 10 outcomes comprising the sexual risk profile, seven achieved bivariate significance, with each of the differences indicating greater risk for those recently engaging in anal sex. In multivariable controlled analyses, six of the seven measures retained statistical significance. Conclusions: African-American adolescent females who engage in penile-anal sex may experience an elevated risk of vaginally-acquired STIs. The findings suggest that, among those having penile-anal sex, several HIV/STI-associated sexual risk behaviours are significantly more prevalent. Thus, penile-anal sex may be an important proxy of overall sexual risk behaviours and can be readily assessed during paediatrician visits as part of a sexual history.
A novel antibiotic, linezolid, reduces intraperitoneal adhesion formation in the rat uterine horn model
Authors: AYTAN HAKAN , CALISKAN AHMET C. , YENER TAMER , DEMIRTURK FAZLI , AYTAN PELIN , YENISEHIRLI AYDAN
Published: May 2009

Objective. To examine the effects of linezolid in prevention of adhesion formation in a rat uterine horn model. Design. Prospective randomized study. Setting. University Experimental Animal Research Laboratory Center. Sample. Ninety female Wistar albino rats. Methods. A dose response study was first conducted with 60 Wistar albino rats that were randomly assigned to six equal groups by administering vehicle (control), 5 mg/kg (Group 1), 15 mg/kg (Group 2), 50 mg/kg (Group 3), 100 mg/kg (Group 4), and 150 mg/kg (Group 5) linezolid starting three days before the adhesion inducing operation and continuing for 14 days postoperatively. Adhesion was scored clinically with a scoring system. The minimum effective dose was found to be 100 mg/kg/day. With this dose time response (starting three days before the operation and continuing for seven days), only preoperative and postoperative administration studies were conducted. Main outcome measures. Extent and severity of adhesions. Results. Total adhesion scores in the control and Groups 1 and 2 were significantly higher when compared with Groups 4 and 5, but not with Group 3. There were no significant differences in the adhesion scores between Groups 3, 4, and 5. In time response arm a total of 10 days treatment was not as effective as 17 days treatment. In postoperative and preoperative arms of the study, it was found that administration of linezolid only postoperatively or preoperatively did not affect adhesion formation significantly when compared with the control group. Conclusion. Linezolid was found to reduce intraperitoneal adhesion formation.
Comparison of aortic valve area measured by magnetic resonance imaging and dual-source computed tomography
Authors: Bruder O. , Jochims M. , Hunold P. , Jensen C. , Forsting M. , Sabin G.V. , Barkhausen J. , Schlosser T.
Published: May 2009

Background: Aortic valve stenosis is the most common type of valve lesion in Europe and North America. Patient treatment is based on disease severity, which is classified by determining the aortic valve area (AVA).

Purpose: To compare dual-source computed tomography (DSCT) with magnetic resonance (MR) imaging for quantifying AVA.

Material and Methods: Thirty-two patients, 28 with normal aortic valve function and four with aortic valve stenosis, who underwent DSCT coronary angiography (Somatom Definition; Siemens, Erlangen, Germany), were included in this study. Retrospective ECG-gated contrast-enhanced DSCT scans with dose-reducing tube current modulation were performed, and data sets were reconstructed in 3% steps of the R–R interval (slice thickness 0.75 mm, increment 0.6 mm). Planimetry of the AVA in systole was assessed on cross-sectional images by multiplanar reformations. Within 48 hours, MR was performed with a 1.5T scanner (Magnetom Sonata; Siemens, Erlangen, Germany) using a balanced steady-state free-precession cine sequence (repetition/echo time 3/1.5 ms, flip angle 60°, spatial resolution 1.4x1.4 mm2). Cine sequences of the left ventricular outflow tract (LVOT) were obtained in two orthogonal planes, and MR planimetry was performed on cross-sectional images of the aortic valve perpendicular to the LVOT images.

Results: AVA assessment by DSCT and MR was feasible in all 32 patients. Mean AVA values determined by DSCT and MR were 4.73±1.5 cm2 and 4.69±1.4 cm2, respectively. A strong positive correlation was found between both imaging modalities ( R=0.98, P<0.001). Bland-Altman analysis demonstrated an excellent intermodality agreement, with a slight underestimation of AVA by DSCT. The mean difference was -0.04 cm2, with a standard deviation of 0.32 cm2.

Conclusion: Retrospective ECG-gated contrast-enhanced DSCT with tube current modulation provides an accurate imaging technique for the assessment of the AVA. Further studies are required to determine whether DSCT also allows for AVA quantification in patients with aortic valve stenosis.
Integrin-mediated axoglial interactions initiate myelination in the central nervous system
Authors: Câmara Joana , Wang Zhen , Nunes-Fonseca Cristina , Friedman Hana C. , Grove Matthew , Sherman Diane L. , Komiyama Noboru H. , Grant Seth G. , Brophy Peter J. , Peterson Alan , ffrench-Constant Charles
Published: May 2009

All but the smallest-diameter axons in the central nervous system are myelinated, but the signals that initiate myelination are unknown. Our prior work has shown that integrin signaling forms part of the cell–cell interactions that ensure only those oligodendrocytes contacting axons survive. Here, therefore, we have asked whether integrins regulate the interactions that lead to myelination. Using homologous recombination to insert a single-copy transgene into the hypoxanthine phosphoribosyl transferase (hprt) locus, we find that mice expressing a dominant-negative β1 integrin in myelinating oligodendrocytes require a larger axon diameter to initiate timely myelination. Mice with a conditional deletion of focal adhesion kinase (a signaling molecule activated by integrins) exhibit a similar phenotype. Conversely, transgenic mice expressing dominant-negative β3 integrin in oligodendrocytes display no myelination abnormalities. We conclude that β1 integrin plays a key role in the axoglial interactions that sense axon size and initiate myelination, such that loss of integrin signaling leads to a delay in myelination of small-diameter axons.
VE-PTP controls blood vessel development by balancing Tie-2 activity
Authors: Winderlich Mark , Keller Linda , Cagna Giuseppe , Broermann Andre , Kamenyeva Olena , Kiefer Friedemann , Deutsch Urban , Nottebaum Astrid F. , Vestweber Dietmar
Published: May 2009

Vascular endothelial protein tyrosine phosphatase (VE-PTP) is an endothelial-specific receptor-type tyrosine phosphatase that associates with Tie-2 and VE-cadherin. VE-PTP gene disruption leads to embryonic lethality, vascular remodeling defects, and enlargement of vascular structures in extraembryonic tissues. We show here that antibodies against the extracellular part of VE-PTP mimic the effects of VE-PTP gene disruption exemplified by vessel enlargement in allantois explants. These effects require the presence of the angiopoietin receptor Tie-2. Analyzing the mechanism we found that anti–VE-PTP antibodies trigger endocytosis and selectively affect Tie-2–associated, but not VE-cadherin–associated VE-PTP. Dissociation of VE-PTP triggers the activation of Tie-2, leading to enhanced endothelial cell proliferation and enlargement of vascular structures through activation of Erk1/2. Importantly, the antibody effect on vessel enlargement is also observed in newborn mice. We conclude that VE-PTP is required to balance Tie-2 activity and endothelial cell proliferation, thereby controlling blood vessel development and vessel size.
The Cognitive Neuroscience of Memory
Authors: Eichenbaum Howard
Published: May 2009

This book details the brain's remarkable capacity for memory. The book is organized into sections corresponding to its four major themes: Connection considers how memory is based on alterations to the communication between nerve cells. Cognition discusses the fundamental psychological structure of memory. Compartmentalization involved the notion that the different forms of memory are accomplished by distinct brain systems. Consolidation refers to processes by which memories are transformed from a labile trace into a permanent store. The book provides insights into how memory works and how it is fundamental to all aspects of cognition, behavior, and emotion.
Amnesia—Learning about Memory from Memory Loss
Authors: Eichenbaum Howard
Published: May 2009

This chapter provides a detailed overview of a patient called H.M., in order to provide a closer perspective on the nature of his amnesia. It explores the distinction between declarative and procedural memory using several examples from the experimental literature on amnesia. H.M. had been severely epileptic for several years. In an effort to alleviate his disorder, the medial temporal lobe area was removed, and the surgery did reduce the frequency of his seizures considerably. However, following the surgery this patient became severely amnesic, and yet showed hardly any other neurological deficits.
Two Distinct Stages of Memory Consolidation
Authors: Eichenbaum Howard
Published: May 2009

This chapter considers two aspects of memory consolidation, one that involves a fixation of memory within synapses over a period of minutes or hours, and another that involves a reorganization of memories that occurs over weeks to years. Topics discussed include cellular events that mediate memory fixation, modulation of memory fixation, influencing memory by hormonal activation associated with emotional arousal, the role of the amygdala in enhancing memory in humans, and brain systems that mediate prolonged processes in memory reorganization.
Evolution
Authors: Iwaniuk Andrew N.
Published: May 2009

This chapter discusses the evolution of the laboratory rat from the origins of rodents in general to the speciation of the genus Rattus. It provides a summary of the evolutionary events leading to R. norvegicus. Because palaeontology, taxonomy, and phylogenetics are intimately related to one another, the chapter is organized in terms of the taxonomy of R. norvegicus. Evolutionary relationships and palaeontological history are discussed with reference to other groups of the same taxonomic rank. For example, the order Rodentia is placed in the context of other mammalian orders. Summarizing the evolutionary history of R. norvegicus provides a basic understanding of how the species has evolved that may be instructive in interpreting the results of behavioral experimentation and/or comparative analyses.
Strains
Authors: Koch Lauren Gerard , Britton Steven L.
Published: May 2009

This chapter discusses the development of inbred strains, which relates directly to the use of experimental design for probing cause and effect at all levels of biological organization. Topics covered include the theoretical basis of inbred strains, model development, and experimental use of inbreds.
Somatosensation
Authors: Hermer-Vazquez Linda , Hermer-Vazquez Raymond , Chapin John K.
Published: May 2009

This chapter discusses five principles for how sensorimotor behaviors are learned and performed by rats, based on new findings from neuroscience. It focuses on nonvibrissal somatosensory processing but also considers examples from the whisker-tactile system or from other sensory modalities. These principles are: (i) analyzed somatosensory feedback information is constantly influencing the ascending somatosensory data stream in rats; (ii) rats are constantly evaluating information across multiple timescales to more accurately predict what will happen in their world; (iii) information from multiple spatial scales is processed simultaneously in the rat; (iv) rat sensory and motor processing are constantly influencing one another; and (v) rat behaviors appear to be organized into survival-related repertoires that can be adapted to novel circumstances.
Vibrissae
Authors: Dyck Richard H.
Published: May 2009

This chapter reviews the anatomical characteristics of the rat's vibrissa sensory apparatus and its growth and dynamic functional characteristics. Topics discussed include the structure and growth of the vibrissal system, motor aspects of vibrissae function, sensory aspects of vibrissae function, and vibrissa system plasticity.
Taste
Authors: Spector Alan C.
Published: May 2009

This chapter reviews the methodological and conceptual issues associated with some common behavioral procedures used to assess taste function. It focuses on laboratory rodents, but many of the principles can be generalized to other species. Topics discussed include stimulus preparation, intake tests, oromotor and somatic taste reactivity, brief-access taste test, and taste stimuli as conditioned cues.
Immune System
Authors: Anisman Hymie , Kusnecov Alexander W.
Published: May 2009

This chapter presents a brief overview of the functioning of the immune system, followed by a description of how immune alterations can affect central nervous system (CNS) processes and behavior in the rat. It also describes how factors that have an impact on psychological processes, most notably stressors, may come to affect immune functioning. In so doing, it introduces numerous caveats concerning the conditions and limitations that determine the nature of the effects observed, making it clear that disentangling the impact of various manipulations on immune activity is complex.
Maternal Behavior
Authors: Rees Stephanie L. , Lovic Vedran , Fleming Alison S.
Published: May 2009

This chapter describes maternal behavior of the laboratory rat and outlines various methods of observing and quantifying this behavior. Although in some rodent biparental species males also show parental behavior, this is not the case for most rodents, including R. norvegicus. However, under certain experimental conditions, males also show many of the components of behavior normally shown by the mother rat. The general and specific methods for the testing of maternal behavior are described. Several environmental and situational factors that affect the expression of maternal behavior are considered.
Social Learning
Authors: Galef, Jr. Bennett G.
Published: May 2009

This chapter begins with a brief review of the literature on social influences on food choices of Norway rats. It describes fieldwork strongly suggesting that interactions between adult free-living rats and their young can determine which foods the young come to eat. It then describes several behavioral processes that have been shown in the laboratory to be sufficient to influence food choice in young rats. Finally, it discusses a type of social influence on rats' food preferences that has already proved to be useful in studies of the physical substrates of learning and memory.
Vocalization
Authors: Sokoloff Greta , Blumberg Mark S.
Published: May 2009

This chapter provides an overview of the contexts, mechanisms, and suggested functions of rat vocalizations. Topics discussed include frequency and temporal characteristics of vocalizations, environmental contexts associated with ultrasonic vocalizations, anatomical considerations, functional significance of ultrasonic vocalizations, and the vocalizing rat as a model of human psychological disorders.
Incentive Behavior
Authors: Balleine Bernard W.
Published: May 2009

This chapter discusses the incentive behavior of rats in the context of evaluative, Pavlovian, and instrumental conditioning procedures. These incentive processes constitute a hierarchy: instrumental incentives involve in part processes engaged by Pavlovian incentives that in part involve processes engaged by evaluative incentives. Whether these incentive processes can in fact be fully dissociated structurally is still a matter of debate, and some current issues are discussed in the final section.
Introduction
Authors: McCloskey Michael
Published: May 2009

This introductory chapter begins with a brief discussion of human cognitive neuropsychological research. It then provides a background of the study of a patient called AH. The main objective of the book is outlined, which is to present a coherent, integrated narrative that systematically lays out the results from the study and explores the theoretical implications in detail. Finally, the organization of the book is presented.
Intact Processing of Nonvisual Location and Orientation Information
Authors: McCloskey Michael
Published: May 2009

The findings discussed in the preceding chapter demonstrate that AH made highly systematic location and orientation errors in a wide variety of tasks with visual stimuli. This chapter shows that whereas AH is severely impaired in perceiving the location and orientation of visual stimuli, she is intact in processing nonvisual location and orientation information. This pattern of results points clearly to a selective deficit in visual perception. A second conclusion, which emerged from the arrows experiment, is that AH's visual deficit affects her performance not only in tasks with visual stimuli but also in tasks where spatial vision may play a role in production of responses, such as tasks with drawing responses.
The Nature of the Deficit: Initial Conclusions
Authors: McCloskey Michael
Published: May 2009

This chapter consolidates the conclusions from the preceding chapters and extends these conclusions on the basis of additional arguments and evidence. It contends that AH suffers from a selective developmental deficit in visual location and orientation perception. This deficit, which probably originated prior to AH's birth or in the early years of her life, affects high-level vision and causes distinctive location and orientation errors in a wide range of visual tasks. The deficit may also affect AH's ability to acquire knowledge in circumstances where processing of visual location and/or orientation information is implicated in the learning process (e.g., learning to spell).
Spatial Representations and Frames of Reference: Theoretical Foundations
Authors: McCloskey Michael
Published: May 2009

This chapter discusses the frame-of-reference concept, arguing that this concept has been the subject of considerable confusion in cognitive and neuroscientific research on spatial representation. In particular, it argues that two distinct questions about frames of reference in the brain have been massively conflated and that the dominant empirical method for probing reference frames speaks to only one of these questions. Finally, it suggests that both questions can be addressed empirically.
Location Representations and Frames of Reference: Evidence from AH
Authors: McCloskey Michael
Published: May 2009

This chapter explores both reference-frame issues in light of results from AH, articulating claims about the nature of location representations at the level of the visual system affected by her deficit. It argues that locations are represented at this level in the form of coordinates that specify distance and direction of displacement from an origin along reference axes.
Visual Updating and Visual Awareness
Authors: McCloskey Michael
Published: May 2009

This chapter presents results concerning AH's head and eye movements and the consequences of these movements for her visual location perception. It shows that AH often moved her head and eyes in the wrong direction when attempting to orient toward a visual stimulus. It then reports a far more surprising result: AH's misperceptions of object location often remained stable across head and eye movements. For this latter result, the chapter offers a speculative interpretation concerning the processes that generate high-level visual location representations. Finally, it discusses the implications of AH's performance for issues concerning the levels of the visual system implicated in conscious visual experience.
Closing The Book on Infectious Disease
Authors: Battin Margaret P. , Francis Leslie P. , Jacobson Jay A. , Smith Charles B.
Published: May 2009

During the formative period of bioethics, the field of public health also directed attention largely away from infectious disease, to issues such as environmental degradation, workplace safety, smoking, and obesity. This chapter presents careful documentation of this development—as well as the virtually complete separation, until quite recently, of the fields of bioethics and public health. The past ten years, by contrast, have seen burgeoning development of public health ethics, including extensive efforts to link protection of public health with the right to health care and international human rights initiatives. The standard picture of public health ethics as utilitarian and bioethics as rights-based has shifted somewhat, especially with rights-based approaches to the HIV epidemic. Nonetheless, it is argued that public health ethics has yet to come to terms with the full theoretical challenges posed by infectious disease.
Old Wine in New Bottles:
Authors: Battin Margaret P. , Francis Leslie P. , Jacobson Jay A. , Smith Charles B.
Published: May 2009

This chapter begins to put the PVV view to work in the analysis of both traditional and newer ethical issues in bioethics. Here, the chapter re-examines staple issues of bioethics such as truth-telling, informed consent, privacy and confidentiality, and end-of-life decision making in light of the importance of taking both victimhood and vectorhood into account. To take one example, refusals of patients to be told the truth that might be respected on traditional autonomy grounds look quite different if the truth at issue includes possibilities of contagion. Informed consent must include a discussion of the risks the patient potentially poses to others—as well as the risks posed by others. Using the PVV view, this chapter also takes up more novel issues about duties of physicians, such as the duty to warn, the duty to treat, and the duty to reduce levels of mistakes. Physicians who are potentially infectious themselves, for example, have a duty to consider their own roles as vectors, not solely the interests of the patient.
From the Magic Mountain to a Dying Homeless Man and His Dog:
Authors: Battin Margaret P. , Francis Leslie P. , Jacobson Jay A. , Smith Charles B.
Published: May 2009

This chapter uses the example of a homeless man with multiple drug-resistant tuberculosis to explore ethical conflicts that arise between the public health officers' emphasis on “control-the-vector” approach to managing tuberculosis patients, which may include involuntary screening, isolation, and coerced treatment, and the concerns of autonomy-oriented traditional medical ethicists that patients' rights be respected. It suggests a synthesis of these competing values and approaches that might be implemented by a physician who cares both for the patient and for the health of the public, and who understands that the individual patient is as vulnerable to being infected by others as others are to being infected by the patient. The chapter also raises issues about care of the dying in transmissible infectious disease: in this case, the patient wants only to go home and be with his dog, but for disease-control reasons cannot be allowed to be at large. The tension is reduced with a creative solution in a way that demonstrates a simple case of recognizing that the patient is both victim and vector at one and the same time.
Constraints in the Control of Infectious Disease
Authors: Battin Margaret P. , Francis Leslie P. , Jacobson Jay A. , Smith Charles B.
Published: May 2009

In the effort to control infectious disease, many different kinds of constraints have been employed: mandatory testing, required or observed treatment, and quarantine and isolation, among others. Although sometimes justified, these constraints have often been misused, as people were left to die in cholera-infected ships anchored offshore or in plague-stricken villages. This chapter begins with an overview of the ethical issues raised by different types of constraints used to control infectious disease. It then uses the PVV view to argue that constraints can be justified if they meet a set of procedural and substantive guarantees. The procedural guarantees are: that there be an important interest, supported by evidence, that the least restrictive alternative be chosen, that constraints be fully disclosed and transparent, and that there be an opportunity for reconsideration. The basic substantive guarantees are personal security, meeting basic needs for survival and treatment, effective communication, the equitable allocation of burdens, and compensation for loss.
Pandemic Planning
Authors: Battin Margaret P. , Francis Leslie P. , Jacobson Jay A. , Smith Charles B.
Published: May 2009

With the pressing risk of avian flu, jurisdictions across the world have devoted considerable attention to pandemic planning. This chapter employs the PVV view about the justifiability of constraints to explore several aspects of pandemic planning that have been less discussed to date. It argues that the use of models must be sensitive to both the risks of too much constraint and to the possibility that there is a mismatch between what models predict and what may actually occur. Too few plans have built in careful mechanisms for reconsideration as pandemic conditions develop. Plans should devote more attention to social distancing—which considers people as vectors—but in so doing should also attend to their plight as victims. It is argued that too few plans have devoted sufficient attention to such matters as the delivery of food, essential medical supplies, or palliative care for those who may become isolated under stay-at-home and home quarantine strategies for pandemic management.
Pandemic Planning and the Justice of Health-Care Distribution
Authors: Battin Margaret P. , Francis Leslie P. , Jacobson Jay A. , Smith Charles B.
Published: May 2009

In pandemic planning, much attention has been paid to justice in the distribution of scarce health care resources: vaccines, anti-virals, and access to advanced modes of treatment such as ventilator support. This chapter examines critically the extent to which some proposals fail to take existing injustice into account. It considers the justice of pandemic planning, arguing that in order to be just, pandemic planning requires attention to basic health care infrastructure for everyone. Without, for example, access to basic primary care, people will be less likely to present for treatment and pandemic disease may not be identified at a time when spread is more readily preventable.