bluuebunny/crossref_metadata_2025 huggingface dataset:
Verification, validation, and uncertainty in computational fluids dynamicsThis article is one of a selection of papers published in this Special Issue on Hydrotechnical Engineering.
Authors: Pelletier D.
Published: July 2010

In this paper, we discuss issues in verification, validation, and uncertainty prediction in computational fluid dynamics (CFD). Mesh adaptation is used to perform the systematic grid refinement studies required for code and simulation verification. We demonstrate the method of manufactured solutions (MMS) for code verification. Examples of successful and failed validation show that reliable prediction can only occur with an appropriate mathematical model of physics along with accurate numerical solution of the differential equations. The paper emphasizes good CFD practices to achieve systematic verification and put validation studies on solid grounds. Finally, the sensitivity equation method (SEM) is used to cascade input data uncertainty through the CFD code for estimating the uncertainty of the flow response.
Évaluation de l’incertitude due au modèle de représentation du réservoir dans les analyses de rupture de barrageLe présent ouvrage fait partie d’une série d’articles publiés dans ce numéro spécial consacré au génie hydrotechnique.
Authors: Tchamen Georges Williams , Gaucher Jérémie
Published: July 2010

Le présent article analyse l’impact du modèle de représentation de la vidange du réservoir sur les résultats de modélisation numérique de rupture de barrage. Le modèle à représentation statique à l’aide de la courbe d’emmagasinement est comparé à celui à représentation dynamique à l’aide d’un modèle de Saint-Venant utilisant la bathymétrie du réservoir. La comparaison est basée sur l’hydrogramme à la brèche, les niveaux maximaux, les surfaces inondées et les temps d’arrivée de l’onde à l’aval pour trois cas de réservoir de tailles différentes. Il ressort que la différence entre les deux modèles de représentation est maximale à la brèche et à l’aval immédiat du barrage, notamment pour le niveau maximal et la surface inondée, et qu’elle s’estompe plus loin à l’aval. L’analyse des résultats de simulation des cas étudiés montre que le modèle statique surestime les rehaussements atteints ainsi que la surface inondée à l’aval du barrage dans une proportion qui peut atteindre 20 %. L’utilisation d’un modèle dynamique de représentation du réservoir peut permettre de réduire de 30 % à 40 % ces surestimations. En l’absence de données bathymétriques du réservoir, la reconstitution de données synthétiques reproduisant la courbe d’emmagasinement pour servir de base à un modèle dynamique du réservoir est examinée. Il apparaît que cette solution peut réduire de façon appréciable l’incertitude due à la représentation statique.
Expression of cystic fibrosis transmembrane conductance regulator in paracervical gangliaThis paper is one of a selection of papers published in this special issue entitled “Second International Symposium on Recent Advances in Basic, Clinical, and Social Medicine” and has undergone the Journal's usual peer review process.
Authors: Su Meng , Guo Yong , Zhao Yingying , Korteweg Christine , Gu Jiang
Published: July 2010

The cystic fibrosis transmembrane conductance regulator (CFTR) is an important protein that acts as a chloride channel and regulates many physiological functions, including salt transport and fluid flow. Mutations in the gene encoding the CFTR protein cause cystic fibrosis. CFTR is expressed in the epithelial cells of the lungs, pancreas, intestines, and other organs. In the peripheral and central nervous system, CFTR expression has been detected in the neurons of rat brains, ganglion cells of rat hearts, human hypothalamus, human spinal cord, and human spinal and sympathetic ganglia. However, CFTR has not been identified in other parts of the nervous system. In this study, we used immunohistochemistry, in situ hybridization, and laser-assisted microdissection (LMD) followed by reverse transcriptase (RT) PCR to identify CFTR proteins and messenger RNA in human and rat paracervical ganglion cells. CFTR and its gene expression were both detected in paracervical ganglion cells, a finding that might link this important protein to the neuronal regulation of female urogenital function. These findings could provide new insights into the symptoms related to the reproductive system frequently observed in female cystic fibrosis patients.
Role of insulin on jejunal PepT1 expression and function regulation in diabetic male and female rats
Authors: Der-Boghossian Asdghig H. , Saad Sara R. , Perreault Claudine , Provost Chantale , Jacques Danielle , Kadi Lina N. , Issa Nahla G. , Sibai Abla M. , El-Majzoub Nadim W. , Bikhazi Anwar B.
Published: July 2010

The aim of this study was to determine whether the jejunal oligopeptide transporter PepT1 is regulated by insulin and whether this regulation is sex-dependent in type 1 diabetic rats. PepT1 expression, real-time polymerase chain reaction, and Western blots were performed using jejunal segments from 4 groups of male and female rats: normal (nondiabetic), insulin-treated nondiabetic, streptozotocin (STZ)-induced diabetic (type 1 diabetes), and insulin-treated diabetic models. Furthermore, the same segments from all groups underwent perfusion to assess uptake of the dipeptide glycylsarcosine through PepT1. Our results showed that insulin treatment of nondiabetic female rats decreased blood glucose level but did not affect nondiabetic male rats. In both male and female diabetic rats, insulin did not completely decrease blood glucose level. Insulin treatment decreased PepT1 mRNA level in nondiabetic male rats and increased mRNA level in nondiabetic female rats without affecting the PepT1 protein level in either sex. Inducing diabetes with STZ increased PepT1 mRNA and protein levels in female rats; however, in diabetic male rats, the increase in mRNA level was accompanied by a decrease in PepT1 protein level. Treatment of diabetic male rats with insulin partially reversed the effect of diabetes on PepT1 mRNA and protein levels, whereas the same treatment completely restored both PepT1 mRNA and protein to control levels in insulin-treated diabetic female rats. In both nondiabetic male and female rats, insulin treatment had no effect on PepT1 influx rate, and STZ treatment decreased the transporter influx rate. Treatment of diabetic male and female rats with insulin significantly increased PepT1 influx rate; however, complete recovery was found only in diabetic female rats. These results clearly show that insulin and diabetes affected blood glucose level as well as PepT1 activity, expression, and protein levels in a sex-dependent manner. These results suggest that a factor, probably estrogen, could be responsible for the sex-dependent effects of diabetes and insulin in PepT1 level and activity.
Peroxisome proliferator-activated receptor γ promotes neuroprotection by modulating cyclic D1 expression after focal cerebral ischemia
Authors: Pei Lichun , Zhang Yanqiao , Zhang Yina , Chu Xiaojie , Zhang Jingyuan , Wang Ruitao , Liu Meiling , Zhu Xiuying , Yu Weigang
Published: July 2010

Peroxisome proliferator-activated receptor γ (PPARγ) has been shown to protect against stroke and improve neurological outcome after cerebral ischemia. This study investigated whether activation of cerebral PPARγ improves recovery from focal cerebral ischemia by reducing expression of cyclin D1, which is associated with programmed neuron death. Focal cerebral ischemia was induced by 90 min of middle cerebral artery occlusion (MCAO), followed by reperfusion. Intracerebroventricular (i.c.v.) infusion of the PPARγ agonist ciglitazone, beginning 5 days before and continuing through 1 day after MCAO, reduced infarct size and cyclin D1 expression in the peri-infarct cortical region. Furthermore, primary cortical neurons treated with ciglitazone showed suppressed expression of cyclin D1 in response to hypoxia–reoxygenation. This protective effect was reversed after cotreatment with the selective PPAR-γ antagonist GW 9662 (2-chloro-5-nitrobenzanilide), clearly demonstrating the involvement of a PPARγ-dependent mechanism. Our data provide evidence that activation of neuronal PPARγ makes a substantial contribution to neuroprotection by preventing cyclin D1 up-regulation in vitro and in vivo.
Cheaters and liars: chemical mimicry at its finestThe present review is one in the special series of reviews on animal-plant interactions.In memory of Jan Tengö (1939–2010), who made exceptional contributions to our understanding of the chemical ecology of solitary bees, including chemical mimicry.
Authors: Vereecken N. J. , McNeil J. N.
Published: July 2010

Chemical mimicry is an essential part of certain interspecific interactions, where the outcome for both species may depend on the degree to which the original signals are mimicked. In this review, we discuss a number of specific cases relating to pollination and obtaining nutrient resources that we believe exemplify recent advances in our understanding of chemical mimicry. Subsequently, we suggest avenues for future ecological and chemical research that should allow us to gain further insight into the evolution of chemical mimicry.
Shear strength of soils derived from the weathering of granite and gneiss in Brazil
Authors: Lacerda Willy A.
Published: July 2010

Research on the properties of residual soils has been continuing in Brazil since the pioneering work by Vargas in 1953. A great number of earth dams built since then and the initiation of graduate courses since 1960 have increased the rate of in-depth studies on this theme. This contribution considers the more recent research on the properties of these soils, mainly shear strength parameters.
Identification of aspect candidates by inspecting use cases descriptions
Authors: Campos Juliana Pinheiro , Braga José Luis , Pereira de Resende Antânio Maria , Osório Silva Carlos Henrique
Published: July 2010

The identification of aspect candidates in the early phases of software development process allows improving the modularization of the requirements, to detect conflicts early and maintain the separation of concerns in the later phases of the process. However, the identification of aspects in initial phases is a non-trivial task, which can be costly and too time-consuming. This paper presents a technique to assist in the identification of aspect candidates in the requirements, through inspection. Two case studies were carried out to evaluate the proposed technique. The results obtained from the case studies let us conclude that the proposed technique facilitates the identification of aspect candidates.
Model driven development approach to natural language generation systems
Authors: Macedo Hendrik
Published: July 2010

Natural Language Generation systems have traditionally been built using
ad-hoc
software engineering practices with no explicit development process and no standard software architecture. This situation has drastically limited professional use of NLG technology. New approaches to NLG application development that considers domain-independence, languages and standards of modern software engineering, could enhance its practical use. This work proposes an NLG reference architecture that leverages the most advanced open standards in software architecture, modeling languages and processing tools. In particular, it is shown how dialogue-based voice-driven NLG applications can be built from the up-to-date Model-driven Architecture (MDA) approach. The implementation of a voice-driven movie recommendation system demonstrates the feasibility of the proposal.
A mathematical reusability model for quantifying the reduction in development effort
Authors: Majumdar Dipankar , Sengupta Sabnam , Kanjilal Ananya , Kundu Swagata , Bhattacharya Swapan
Published: July 2010

Software Effort and Cost Estimation is a very important activity that includes very uncertain elements. In the context of object-oriented software, traditional methods and metrics were extended to help managing this activity. Use Case Points (UCP) is a very well known metrics used for estimation of object-oriented systems. Use case models are used in Object-Oriented Analysis for capturing and describing the Functional-Requirements of a system. Several methods for estimating software development effort are based on attributes of a use case model. In this paper, we propose a mathematical model based on vectors to measure reusability of software design in terms of reusability of the use cases. Increasing reusability of the use case model would lead to decrease in development effort. Using the vector model, we propose an approach to measure Complexity Reduction Factor (CRF) which measures percentage decrease in effort and hence in cost with increasing reusability. This quantitative analysis of effort reduction with increased reusability would enable us in designing reusable and cost effective software much earlier in software development life cycle, right at the requirement engineering phase. We have used requirements of an Insurance system as a case study to illustrate our approach.
A soft computing based approach to estimate reusability of software components
Authors: Sagar Shrddha , Nerurkar N. W. , Sharma Arun
Published: July 2010

Component-based development (CBD) is the process of assembling existing software components in an application such that they satisfy a predefined functionality. Reduced development time, effort and cost are few merits of CBD. As components are black-box, therefore the use of conventional metrics in CBD is difficult, because these metrics needs analysis of source codes. To assess the reuse of component, it is important to estimate reusability of these components. Present paper discusses reusability in relation to CBD and proposes a reusability metrics for black box components. It identifies the factors affecting reusability of the components and establishes relationship in between these factors and reusability. Fuzzy logic based approach is used to estimate reusability and results found on real time applications are quite satisfactory. The proposed approach can be used by the application developers to select highly reusable components in the systems which will eventually help in maintaining the system in a better way.
CRAYSE
Authors: Radhakishan V. , Farook Yaser , Selvakumar S.
Published: July 2010

CRAYSE1 is a SEarch WHIle CRAwl application, intended to perform fast searching of text in web pages. A Web crawler is a computer program that browses the World Wide Web in a methodical, automated manner. This process is also called spidering. Search engines, use spidering as a means of providing up-to-date data. Most of the existing web-crawlers archive the contents of the web starting from the input URL. Search engines index the results of web-crawlers and then perform searching when queried. As such, the searching is not performed while crawling. Hence such softwares can not be used for general use by web browsers. Also, the existing search mechanism in web browsers, search only on the current page and not recursively through all the links present in that page. In order to overcome such disadvantages, we propose in this paper to implement a web crawler that searches for a pattern efficiently and recursively through all the links including pdf links while crawling. CRAYSE can be used as a general purpose open source software by web browsers. It can also be used for offine searching. Further, the applications that require selective archival of web pages (based on the presence of a key word), can deploy CRAYSE for efficient search operations. This paper focusses on the design and implementation of CRAYSE and its demonstration through web applications.
Dependence analysis of software component
Authors: Ratneshwer  , Tripathi A. K.
Published: July 2010

Dependence analysis among software components is still a challenging issue for practitioners and researchers. We propose the representation of dependence among software components as a Component Interaction Graph (CIG). We make use of a well known data structure consisting of "two linear arrays" to represent the CIG. Based on this representation, we derived some dependency relationships. We evaluate the relationships by Weyukers' properties. We also have demonstrated with a possible CIG for a CBS to show the quantitative characteristics of the derived relationships. This work starts a discussion and calls for more extensive research oriented studies by professionals and academicians for perfection of the approach.
The saliency of anomalies in animated human characters
Authors: Hodgins Jessica , Jörg Sophie , O'Sullivan Carol , Park Sang Il , Mahler Moshe
Published: July 2010

Virtual characters are much in demand for animated movies, games, and other applications. Rapid advances in performance capture and advanced rendering techniques have allowed the movie industry in particular to create characters that appear very human-like. However, with these new capabilities has come the realization that such characters are yet not quite “right.” One possible hypothesis is that these virtual humans fall into an “Uncanny Valley”, where the viewer's emotional response is repulsion or rejection, rather than the empathy or emotional engagement that their creators had hoped for. To explore these issues, we created three animated vignettes of an arguing couple with detailed motion for the face, eyes, hair, and body. In a set of perceptual experiments, we explore the relative importance of different anomalies using two different methods: a questionnaire to determine the emotional response to the full-length vignettes, with and without facial motion and audio; and a 2AFC (two alternative forced choice) task to compare the performance of a virtual “actor” in short clips (extracts from the vignettes) depicting a range of different facial and body anomalies. We found that the facial anomalies are particularly salient, even when very significant body animation anomalies are present.
Perceptually motivated guidelines for voice synchronization in film
Authors: Carter Elizabeth J. , Sharan Lavanya , Trutoiu Laura , Matthews Iain , Hodgins Jessica K.
Published: July 2010

We consume video content in a multitude of ways, including in movie theaters, on television, on DVDs and Blu-rays, online, on smart phones, and on portable media players. For quality control purposes, it is important to have a uniform viewing experience across these various platforms. In this work, we focus on voice synchronization, an aspect of video quality that is strongly affected by current post-production and transmission practices. We examined the synchronization of an actor's voice and lip movements in two distinct scenarios. First, we simulated the temporal mismatch between the audio and video tracks that can occur during dubbing or during broadcast. Next, we recreated the pitch changes that result from conversions between formats with different frame rates. We show, for the first time, that these audio visual mismatches affect viewer enjoyment. When temporal synchronization is noticeably absent, there is a decrease in the perceived performance quality and the perceived emotional intensity of a performance. For pitch changes, we find that higher pitch voices are not preferred, especially for male actors. Based on our findings, we advise that mismatched audio and video signals negatively affect viewer experience.
How does presentation method and measurement protocol affect distance estimation in real and virtual environments?
Authors: Grechkin Timofey Y. , Nguyen Tien Dat , Plumert Jodie M. , Cremer James F. , Kearney Joseph K.
Published: July 2010

We conducted two experiments that compared distance perception in real and virtual environments in six visual presentation methods using either timed imagined walking or direct blindfolded walking, while controlling for several other factors that could potentially impact distance perception. Our presentation conditions included unencumbered real world, real world seen through an HMD, virtual world seen through an HMD, augmented reality seen through an HMD, virtual world seen on multiple, large immersive screens, and photo-based presentation of the real world seen on multiple, large immersive screens. We found that there was a similar degree of underestimation of distance in the HMD and large-screen presentations of virtual environments. We also found that while wearing the HMD can cause some degree of distance underestimation, this effect depends on the measurement protocol used. Finally, we found that photo-based presentation did not help to improve distance perception in a large-screen immersive display system. The discussion focuses on points of similarity and difference with previous work on distance estimation in real and virtual environments.
Designing coded feedback for efficient network coding based opportunistic routing
Authors: Koutsonikolas Dimitrios , Wang Chih-Chun , Hu Y. Charlie
Published: July 2010

A fundamental challenge faced by network coding (NC)-based opportunistic routing (OR) protocols is determining how many coded packets each forwarding node (FN) should transmit. Existing protocols address this challenge by combining NC with offline loss rate based heuristics to eliminate the overhead of feedback exchange, often at the cost of reduced performance in dynamic wireless environments. In this paper, we present a novel solution to this challenge through the design of the CCACK protocol. CCACK introduces an online Cumulative Coded ACKnowledgment scheme which allows the protocol to sustain high performance in dynamic wireless environments, with practically zero overhead.
BodySec
Authors: Shi Jinyang , Lam Kwok-Yan , Gu Ming , Li Husheng
Published: July 2010

This paper proposes a new biometric-based key distribution scheme, BodySec, for energyefficient secure communications in wireless body sensor networks. To the best of our knowledge, BodySec is the first approach that can remove the timing synchronization assumption of the biometric inter-pulse signals among different biomedical sensors. The basic design is to represent the biometrics as an unordered set of short-term slots, then transform the problem of key agreement using biometrics into a problem of set reconciliation, finally ensure the different sensors can possess the same keys with low energy consumption. The experimental results on the PhysioBank electrocardiogram database demonstrate that BodySec opens up a new feasible way for energy-efficient key distribution in the future human-centered wireless system characterized by timing asynchronism and limited power.
Numerical modeling of oxygen distributions in cortical and cancellous bone: oxygen availability governs osteonal and trabecular dimensions
Authors: Zahm Adam M. , Bucaro Michael A. , Ayyaswamy Portonovo S. , Srinivas Vickram , Shapiro Irving M. , Adams Christopher S. , Mukundakrishnan Karthik
Published: July 2010

Whereas recent work has demonstrated the role of oxygen tension in the regulation of skeletal cell function and viability, the microenvironmental oxemic status of bone cells remains unknown. In this study, we have employed the Krogh cylinder model of oxygen diffusion to predict the oxygen distribution profiles in cortical and cancellous bone. Under the assumption of saturation-type Michaelis-Menten kinetics, our numerical modeling has indicated that, under steady-state conditions, there would be oxygen gradients across mature osteons and trabeculae. In Haversian bone, the calculated oxygen tension decrement ranges from 15 to 60%. For trabecular bone, a much shallower gradient is predicted. We note that, in Haversian bone, the gradient is largely dependent on osteocyte oxygen utilization and tissue oxygen diffusivity; in trabecular bone, the gradient is dependent on oxygen utilization by cells lining the bone surface. The Krogh model also predicts dramatic differences in oxygen availability during bone development. Thus, during osteon formation, the modeling equations predict a steep oxygen gradient at the initial stage of development, with the gradient becoming lesser as osteonal layers are added. In contrast, during trabeculum formation, the oxygen gradient is steepest when the diameter of the trabeculum is maximal. Based on these results, it is concluded that significant oxygen gradients exist within cortical and cancellous bone and that the oxygen tension may regulate the physical dimensions of both osteons and bone trabeculae.
TRB3 is stimulated in diabetic kidneys, regulated by the ER stress marker CHOP, and is a suppressor of podocyte MCP-1
Authors: Morse Elizabeth , Schroth Jana , You Young-Hyun , Pizzo Donald P. , Okada Shinichi , RamachandraRao Satish , Vallon Volker , Sharma Kumar , Cunard Robyn
Published: July 2010

The prevalence of diabetic nephropathy continues to rise, highlighting the importance of investigating and discovering novel treatment strategies. TRB3 is a kinase-like molecule that modifies cellular survival and metabolism and interferes with signal transduction pathways. Herein, we report that TRB3 expression is increased in the kidneys of type 1 and type 2 diabetic mice. TRB3 is expressed in conditionally immortalized podocytes; however, it is not stimulated by elevated glucose. The diabetic milieu is associated with increased oxidative stress and circulating free fatty acids (FFA). We show that reactive oxygen species (ROS) such as H2O2 and superoxide anion (via the xanthine/xanthine oxidase reaction) as well as the FFA palmitate augment TRB3 expression in podocytes. C/EBP homologous protein (CHOP) is a transcription factor that is associated with the endoplasmic reticulum stress response. CHOP expression increases in diabetic mouse kidneys and in podocytes treated with ROS and FFA. In podocytes, transfection of CHOP increases TRB3 expression, and ROS augment recruitment of CHOP to the proximal TRB3 promoter. MCP-1/CCL2 is a chemokine that contributes to the inflammatory injury associated with diabetic nephropathy. In these studies, we demonstrate that TRB3 can inhibit basal and stimulated podocyte production of MCP-1. In summary, enhanced ROS and/or FFA associated with the diabetic milieu induce podocyte CHOP and TRB3 expression. Because TRB3 inhibits MCP-1, manipulation of TRB3 expression could provide a novel therapeutic approach in diabetic kidney disease.
Frequency-Dependent Release of Substance P Mediates Heterosynaptic Potentiation of Glutamatergic Synaptic Responses in the Rat Visual Thalamus
Authors: Masterson Sean P. , Li Jianli , Bickford Martha E.
Published: July 2010

To investigate the interaction between peptides and glutamatergic synapses in the dorsal thalamus, we compared the frequency-dependent plasticity of excitatory postsynaptic potentials (EPSPs) in the tectorecipient zone of rodent lateral posterior nucleus (LPN), which is densely innervated by axons that contain the neuromodulator substance P (SP). Immunocytochemistry and confocal and electron microscopy revealed that neurokinin 1 (NK1) receptors are distributed on the dendrites of LPN cells, whereas SP is contained in axons originating from the superior colliculus (SC) and is reduced following SC lesions. In vitro whole cell recordings in parasagittal slices revealed that stimulation of the SC or optic radiations (corticothalamic axons [CTXs]) evoked LPN EPSPs that increased in amplitude with increasing stimulation intensity, suggesting convergence. With 0.5- to 10-Hz stimulus trains, CTX EPSP amplitudes displayed frequency-dependent facilitation, whereas SC EPSP amplitudes were unchanged. High-frequency SC stimulation (100 Hz for 0.5 s), or bath application of SP, resulted in gradual increases in both SC and CTX EPSP amplitudes to twofold or greater above baseline within 15–20 min poststimulation/application. This enhancement correlated with increases in input resistance and both the potentiation and resistance change were abolished in the presence of the NK1 antagonist L-703,606. These results indicate that SP is released when SC-LPN neurons fire at high frequency and SP acts postsynaptically via NK1 receptors to potentiate subsequent LPN responses to both cortical and tectal inputs. We suggest that the SP-mediated potentiation of synaptic responses may serve to amplify responses to threatening objects that move across large regions of the visual field.
Manual Skill Generalization Enhanced by Negative Viscosity
Authors: Huang Felix C. , Patton James L. , Mussa-Ivaldi Ferdinando A.
Published: July 2010

Recent human-machine interaction studies have suggested that movement augmented with negative viscosity can enhance performance and can even promote better motor learning. To test this, we investigated how negative viscosity influences motor adaptation to an environment where forces acted only in one axis of motion. Using a force-feedback device, subjects performed free exploratory movements with a purely inertia generating forces proportional to hand acceleration, negative viscosity generating destabilizing forces proportional to hand velocity, or a combination of the acceleration and velocity fields. After training, we evaluated each subject's ability to perform circular movements in only the inertial field. Combined training resulted in lowest error and revealed similar responses as inertia training in catch trials. These findings are remarkable because negative viscosity, available only during training, evidently enhanced learning when combined with inertia. This success in generalization is consistent with the ability of the nervous system to decompose the perturbing forces into velocity and acceleration dependent components. Compared with inertia, the combined group exhibited a broader range of speeds along the direction of maximal perturbing force. Broader exploration was also correlated with better performance in subsequent evaluation trials; this suggests that negative viscosity improved performance by enhancing identification of each force field. These findings shed light on a new way to enhance sensorimotor adaptation through robot-applied augmentation of mechanics.
Neural Correlates of Color-Selective Metacontrast in Human Early Retinotopic Areas
Authors: Maeda Kiyohiro , Yamamoto Hiroki , Fukunaga Masaki , Umeda Masahiro , Tanaka Chuzo , Ejima Yoshimichi
Published: July 2010

Metacontrast is a visual illusion in which the visibility of a target stimulus is virtually lost when immediately followed by a nonoverlapping mask stimulus. For a colored target, metacontrast is color-selective, with target visibility markedly reduced when the mask and target are the same color, but only slightly reduced when the colors differ. This study investigated neural correlates of color-selective metacontrast for cone-opponent red and green stimuli in the human V1, V2, and V3 using functional magnetic resonance imaging. Neural activity was suppressed when the target was rendered less visible by the same-colored mask, and the suppression was localized in the cortical region retinotopically representing the target, correlating with the perceptual topography of visibility/invisibility rather than the physical topography of the stimulus. Retinotopy-based group analysis found that activity suppression was statistically significant for V2 and V3 and that its localization to the target region was statistically significant for V2. These results suggest that retinotopic color representations in early visual areas, especially in V2, are closely linked to the visibility of color.
Performance Monitoring Local Field Potentials in the Medial Frontal Cortex of Primates: Supplementary Eye Field
Authors: Emeric Erik E. , Leslie Melanie , Pouget Pierre , Schall Jeffrey D.
Published: July 2010

We describe intracranial local field potentials (LFPs) recorded in the supplementary eye field (SEF) of macaque monkeys performing a saccade countermanding task. The most prominent feature at 90% of the sites was a negative-going polarization evoked by a contralateral visual target. At roughly 50% of sites a negative-going polarization was observed preceding saccades, but in stop signal trials this polarization was not modulated in a manner sufficient to control saccade initiation. When saccades were canceled in stop signal trials, LFP modulation increased with the inferred magnitude of response conflict derived from the coactivation of gaze-shifting and gaze-holding neurons. At 30% of sites, a pronounced negative-going polarization occurred after errors. This negative polarity did not appear in unrewarded correct trials. Variations of response time with trial history were not related to any features of the LFP. The results provide new evidence that error-related and conflict-related but not feedback-related signals are conveyed by the LFP in the macaque SEF and are important for identifying the generator of the error-related negativity.
Natalizumab and Regulation of Cerebral Blood Flow: Results from an Observational Study
Authors: Reinhard Matthias , Rosengarten Bernhard , Kirchhoff Luise , Hetzel Andreas , Rauer Sebastian
Published: July 2010

Background: Natalizumab inhibits adherence of leukocytes to the cerebral endothelium. Since leukocytes play a role in regulating vascular tone, natalizumab may also affect cerebral vasoregulation. The aim of this observational study was to investigate whether neurovascular coupling and cerebral autoregulation are altered following routine clinical infusion of natalizumab in patients with relapsing-remitting multiple sclerosis. Methods: In 18 patients receiving regular infusion of 300 mg natalizumab, neurovascular coupling to visual stimulation and dynamic cerebral autoregulation (phase and gain of 0.1-Hz oscillations) were measured by transcranial Doppler ultrasound (before, and 2 h and 2 days after the infusion). A repeated examination 28 days after infusion served as a control situation. Results: Neurovascular coupling was altered 2 h and 2 days after infusion with an overshooting initial hemodynamic response. After 28 days, neurovascular coupling was similar to values before the infusion. Dynamic cerebral autoregulation, cerebral blood flow velocity and pulsatility index in the middle and posterior cerebral artery were unaltered. Conclusion: Natalizumab infusion is associated with a temporarily increased initial hyperemia to functional activation. Such a hyperreactivity suggests an increased bioavailability of nitric oxide during functional activation.
Increased Hospitalizations for Ischemic Stroke with Comorbid Diabetes and Residential Proximity to Sources of Organic Pollutants: A 12-Year Population-Based Study
Authors: Sergeev Alexander V. , Carpenter David O.
Published: July 2010

Background: Evidence is emerging that exposure to persistent organic pollutants (POP) is a risk factor for atherosclerosis-related diseases and for diabetes mellitus (DM). We hypothesized that residential proximity to sources of POP will be associated with an increase in hospitalization rates for ischemic stroke (IS) with comorbid DM (IS-DM). Methods: We examined IS-DM hospitalization rates in the New York State (exclusive of New York City) during a 12-year period. POP exposure status was assessed based on residency in a zip code containing or abutting environmental sources of POP. Adjusted relative risks (RR) of IS-DM hospitalization were estimated by multivariate Poisson regression. Results: A statistically significant 10% increase in IS-DM hospitalization rates was observed in populations environmentally exposed to POP (adjusted RR 1.10, 95% confidence interval, CI, 1.01–1.20; p = 0.031). IS-DM hospitalization rates were also higher in males (adjusted RR 1.34, 95% CI 1.30–1.39; p < 0.001), in blacks (adjusted RR 4.54, 95% CI 4.16–4.94; p < 0.001) and in older age groups (p for trend <0.001). Conclusions: Residential proximity to sources of POP is associated with an increase in RR of IS-DM hospitalization. Our findings support the hypothesis of POP being a risk factor for IS. Further studies are warranted.
Serotonin Transporter Gene Polymorphism Associated with Short-Term Treatment Response to Venlafaxine
Authors: Lee Sang-Hyuk , Choi Tae Kyou , Lee Eun , Seok Jeong-Ho , Lee Sung Hee , Lee Hong Shick , Kim Se Joo
Published: July 2010

Background: Polymorphisms of serotonin transporter, especially serotonin transporter linked promoter region (5- HTTLPR) and serotonin transporter intron 2 variable number tandem repeat (5-HTTVNTR), have been suggested to be associated with treatment response to selective serotonin reuptake inhibitors. However, there have been only few reports of the association between 5-HTTLPR or 5-HTTVNTR and treatment response to venlafaxine. Methods: 84 Korean major depressive disorder patients were included in this study. They were administered 75 mg of venlafaxine XR (extended release) for 1 week and then took 150 mg for the next 3 weeks. All patients were evaluated at baseline and week 4 by the Hamilton Depression Rating Scale (HAM-D), Montgomery-Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory (BDI), Hamilton Anxiety Rating Scale (HAM-A), and Beck Anxiety Inventory (BAI). Results: (1) Treatment response of depressive symptoms (BDI, HAM-D, MADRS) to venlafaxine at week 4 was associated with the non-s/s (l/l and l/s) genotype of 5-HTTLPR; (2) in repeated measures ANOVA, the BDI, MADRS and HAM-A scores decreased more significantly in patients with the non-s/s genotype than in those with the s/s genotype, and (3) multiple regression analyses suggested that the 5-HTTLPR polymorphism is a predictive factor for short-term treatment response to venlafaxine. However, 5-HTTVNTR showed no significant association with treatment response to venlafaxine. Both 5-HTTLPR and 5-HTTVNTR were not associated with side effects of venlafaxine. Conclusion: The 5-HTTLPR non-s/s genotype can be associated with venlafaxine treatment responses. However, further large-scale studies are warranted to confirm this finding.
Sensibility of Linkage Information and Effectiveness of Estimated Distributions
Authors: Chuang Chung-Yao , Chen Ying-ping
Published: July 2010

The probabilistic model building performed by estimation of distribution algorithms (EDAs) enables these methods to use advanced techniques of statistics and machine learning for automatic discovery of problem structures. However, in some situations, it may not be possible to completely and accurately identify the whole problem structure by probabilistic modeling due to certain inherent properties of the given problem. In this work, we illustrate one possible cause of such situations with problems consisting of structures with unequal fitness contributions. Based on the illustrative example, we introduce a notion that the estimated probabilistic models should be inspected to reveal the effective search directions and further propose a general approach which utilizes a reserved set of solutions to examine the built model for likely inaccurate fragments. Furthermore, the proposed approach is implemented on the extended compact genetic algorithm (ECGA) and experiments are performed on several sets of additively separable problems with different scaling setups. The results indicate that the proposed method can significantly assist ECGA to handle problems comprising structures of disparate fitness contributions and therefore may potentially help EDAs in general to overcome those situations in which the entire problem structure cannot be recognized properly due to the temporal delay of emergence of some promising partial solutions.
Male territoriality in a social sciurid, Cynomys gunnisoni: what do patterns of paternity tell us?
Authors: Verdolin  , Slobodchikoff
Published: July 2010

In many social sciurids, male territoriality confers significant mating advantages. We evaluated resident male paternity in Gunnison's prairie dogs (Cynomys gunnisoni), a colonial ground-dwelling sciurid, where males and females cooperatively defend territories. Contrary to findings reported for other social sciurids, our results show that territorial resident males do not gain significant reproductive advantages. Resident males sired the majority of offspring from their respective territories only 10.5% of the time. A single non-resident male sired equal or greater number of offspring than any single resident male 71.2% of the time. While adult males were more likely to sire a greater number of offspring, standard heterozygosity, body mass, and territory size were not significant predictors of how many offspring a male sired. In addition, the number of other males present did not influence the number of offspring sired by any given resident male. However, territory size was significantly correlated with overall offspring number and mean litter size per female, suggesting a potential reproductive advantage for females that occupy larger, better quality territories. Previous work has demonstrated that the cooperative defence of territories by both males and females permits enhanced access to food resources critical to overwinter survival. Our results have important implications for studies that do not distinguish between social and mating systems, because they suggest that individual mating strategies may be different from the social strategies that emerge in response to resource availability.
Four new species of Heth Cobb, 1898 (Rhigonematida: Hethidae) from Vietnamese diplopods
Authors: Malysheva Svetlana V. , Spiridonov Sergei E.
Published: July 2010

Four new species of Heth are described from diplopods collected in different parts of Viet Nam: Heth vietnamensis sp. n. and H. tonkinensis sp. n. in Ba Vi National Park, Ha Tay Province; H. taybaci sp. n. in Lai Chau Province and H. taynguyeni sp. n. in Chu Yang Sin National Park, Dak Lak Province. The new species are morphologically related to those described from Papua New Guinea, but are differentiated by the form of the female cuticular armature. Heth vietnamensis sp. n. is characterised by the posterior end of the lappets overhanging the anterior pair of the lateral spines, the similar size of spines in both pairs and the presence of two pairs of small papillae on the anterior lip of the cloacal aperture. Heth tonkinensis sp. n. can be differentiated from the other species by having the longest lappets, lateral spines with fused bases and the unequal-sized spicule heads. Heth taybaci sp. n. has the shortest lappets of the described Vietnamese species, has gaps between the lateral spines that are wider than the spine base and the presence of a bursa-like cuticular fold at cloacal aperture level. Heth taynguyeni sp. n. males also have a bursa-like cuticular fold but, unlike H. taybaci sp. n., this species is characterised by the bifurcate distal tips of the spicule and the undulating inner margin of the lappets.
Racial Typicality, Racial Identity, and Health Behaviors: A Case for Culturally Sensitive Health Interventions
Authors: Harvey Richard D. , Afful Stephanie E.
Published: July 2010

Culturally sensitive health interventions have proven to be vitally important for the elimination of the health disparities that Black Americans face. The purpose of this study was to illuminate the role and importance of health behavior racial typicality and racial identification in how Black Americans view and engage in health behaviors. Black Americans completed racial identity measures and rated a variety of both health-promoting and health-compromising behaviors on whether they were more typical of Blacks or Whites (i.e., racial typicality), personal importance, and frequency of engagement. Results indicated the extent to which health behaviors were viewed as relatively more descriptive of Blacks (rather than Whites) was associated with higher perceived importance and greater frequency of engagement, particularly among those reporting higher levels of nationalist racial identification. Finally, health behavior importance mediated the relationship between racial typicality of the behavior and engagement in the behavior. The results of the study are discussed in terms of their implications for providing empirical support for the necessity of culturally tailored interventions in eliminating Black American health disparities.
Network Theory of Organization: A Multilevel Approach
Authors: Moliterno Thomas P. , Mahony Douglas M.
Published: July 2010

Management research regularly considers social networks and their effects on a wide range of organizational phenomena. Scholars employing the social network perspective have generated a considerable body of organizational research, with much of this scholarship single-level in its focus: exploring how networks of individuals, groups, or firms relate to organizational outcomes at the same level of analysis. However, given that organizations are multilevel systems, a network theory of the organization should, by definition, be multilevel in its scope, considering how networks at one level of the organizational system influence networks at higher and/or lower levels. In this article, the authors overlay canonical multilevel theory on the social network perspective to derive postulates defining the broad theoretical domain of a multilevel network theory of organization. The link between these two theoretical perspectives is the graph theoretical notion of systems of nested networks, allowing the authors to examine how an observed network structure at one level of the system of organizational networks relates to network structures and effects at higher or lower levels of the system.
Failure to Apply the Flynn Correction in Death Penalty Litigation: Standard Practice of Today Maybe, but Certainly Malpractice of Tomorrow
Authors: Reynolds Cecil R. , Niland John , Wright John E. , Rosenn Michal
Published: July 2010

The Flynn Effect is a well documented phenomenon demonstrating score increases on IQ measures over time that average about 0.3 points per year. Normative adjustments to scores derived from IQ measures normed more than a year or so prior to the time of testing an individual have become controversial in several settings but especially so in matters of death penalty litigation. Here we make the argument that if the Flynn Effect is real, then a Flynn Correction should be applied to obtained IQs in order to obtain the most accurate estimate of IQ possible. To fail to provide the most accurate estimate possible in matters that are truly life and death decisions seems wholly indefensible.
Involving Developing Countries in the Evaluation of Development Cooperation: The Case of a Joint Evaluation of Development Cooperation between Ghana and Denmark
Authors: Mensa-Bonsu Isaac F. , Andersen Margrethe Holm
Published: July 2010

Joint evaluation of development cooperation is becoming more imperative within the framework of the Paris Declaration. It has, however, been noted that the documentation of practical experience with evaluations conducted in a joint fashion is missing. This article seeks to contribute to the debate on the practical implications of conducting joint evaluations. The model adopted involves one donor (Denmark) and one recipient country (Ghana) working as equal partners in drafting the terms of reference (ToR) for the evaluation, procuring consultants, managing the entire process and reviewing the draft reports prepared by the consultants. Principal lessons include: (a) early involvement of the recipient country in the joint evaluation is essential, (b) joint development of the ToR ensures mutual benefits, (c) a Memorandum of Understanding (MoU) strengthens the collaboration, (d) the use of reference groups ensures that the evaluation results are relevant and (e) the use of new communication technologies can help facilitate joint evaluation management. The article concludes that engagement in a joint evaluation is time- and resource-demanding and requires a strong commitment from both sides.