bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced levels of cyclic AMP contribute to the enhanced oxidative stress in vascular smooth muscle cells from spontaneously hypertensive ratsThis article is one of a selection of papers published in the special issue Bridging the Gap: Where Progress in Cardiovascular and Neurophysiologic Research Meet.
Authors: Saha Soumya , Li Yuan , Anand-Srivastava Madhu B.
Published: April 2008

We have earlier shown that aortic vascular smooth muscle cells (VSMC) from 12-week-old spontaneously hypertensive rats (SHR) exhibited enhanced production of superoxide anion (O2–) compared with Wistar–Kyoto (WKY) rats. This production was attenuated to control levels by losartan, an angiotensin II (Ang II) AT1-receptor antagonist, suggesting that the AT1receptor is implicated in enhanced oxidative stress in SHR. Since AT1receptor activation signals via adenylyl cyclase inhibition and decreases cAMP levels, it is possible that AT1receptor-mediated decreased levels of cAMP contribute to the enhanced production of O2–in SHR. The present study was undertaken to investigate this possibility. The basal adenylyl cyclase activity as well as isoproterenol and forskolin-mediated stimulation of adenylyl cyclase was significantly attenuated in VSMC from 12-week-old SHR compared with those from WKY rats, whereas Ang II-mediated inhibition of adenylyl cyclase was significantly enhanced by about 70%, resulting in decreased levels of cAMP in SHR. NADPH oxidase activity and the levels of O2–were significantly higher (about 120% and 200%, respectively) in VSMC from SHR than from WKY rats. In addition, the levels of p47phoxand Nox4 proteins, subunits of NADPH oxidase, were significantly augmented about 35%–40% in VSMC from SHR compared with those from WKY rats. Treatment of VSMC from SHR with 8Br-cAMP, as well as with cAMP-elevating agents such as isoproterenol and forskolin, restored to control WKY levels the enhanced activity of NADPH oxidase and the enhanced levels of O2–, p47phox, and Nox4. Furthermore, in the VSMC A10 cell line, 8Br-cAMP also restored the Ang II-evoked enhanced production of O2–, NADPH oxidase activity, and enhanced levels of p47phoxand Nox4 proteins to control levels. These data suggest that decreased levels of cAMP in SHR may contribute to the enhanced oxidative stress in SHR and that increasing the levels of cAMP may have a protective effect in reducing oxidative stress and thereby improve vascular function.
COMPLEX WAVE NUMBERS IN THE VICINITY OF THE SCHWARZSCHILD EVENT HORIZON
Authors: SHARIF M. , SHEIKH UMBER
Published: April 2008

This paper is devoted to investigate the cold plasma wave properties outside the event horizon of the Schwarzschild planar analogue. The dispersion relations are obtained from the corresponding Fourier analyzed equations for nonrotating and rotating, nonmagnetized and magnetized backgrounds. These dispersion relations provide complex wave numbers. The wave numbers are shown in graphs to discuss the nature and behavior of waves and the properties of plasma lying in the vicinity of the Schwarzschild event horizon.
FIRST OBSERVATION OF THE NEUTRON SPIN ROTATION FOR LAUE DIFFRACTION IN A DEFORMED NONCENTROSYMMETRIC CRYSTAL
Authors: FEDOROV V. V. , LAPIN E. G. , YU. SEMENIKHIN S. , VORONIN V. V. , LELIÈVRE-BERNA E. , NESVIZHEVSKY V. , PETOUKHOV A. , SOLDNER T. , TASSET F.
Published: April 2008

Detailed study of a neutron Laue diffraction in a noncentrosymmetric crystal was carried out using a prototype of the experimental setup to measure the neutron electric dipole moment (nEDM) by Laue diffraction method (LDM). A new kind of spin rotation effect was observed for the first time. We attribute this effect to a difference of the two Bloch waves amplitudes in the crystal, which is caused by the presence of the definite small crystal deformation. In a revised scheme of the experiment, this effect could be exploited for a purposeful manipulation of the Bloch waves.
SINGULAR POINTS OF QUADRATIC SYSTEMS: A COMPLETE CLASSIFICATION IN THE COEFFICIENT SPACE ℝ12
Authors: ARTES JOAN C. , LLIBRE JAUME , VULPE NICOLAE
Published: April 2008

Planar quadratic differential systems occur in many areas of applied mathematics. Although more than one thousand papers were written on these systems, a complete understanding of this class is still missing. Classical problems, and in particular, Hilbert's 16th problem [Hilbert,1900], are still open for this class. Even when not dealing with limit cycles, still some problems have remained unsolved like a complete classification of different phase portraits without limit cycles.

For some time it was thought (see [Coppel, 1966]) there could exist a set of algebraic functions whose signs would completely determine the phase portrait of a quadratic system. Nowadays we already know that this is not so, and that there are some analytical, nonalgebraic functions that also play a role when dealing with limit cycles and separatrix connections.

However, it is possible to find out a set of algebraic functions whose signs determine the characteristics of all finite and infinite singular points. Most of the work up to now has dealt with this problem studying it using different normal forms adapted to some subclasses of quadratic systems. A general work useful for any quadratic system regardless of affine changes has only been done for the study of infinite singular points [Schlomiuk et al., 2005].

In this paper, we give a complete global classification of quadratic differential systems according to their topological behavior in the vicinity of the finite singular points. Our classification Main Theorem gives us a complete dictionary describing the local behavior of finite singular points using algebraic invariants and comitants which are a powerful tool for algebraic computations. Linking the result of this paper with the main one of [Schlomiuk et al., 2005] which uses the same algebraic invariants, it is possible to complete the algebraic classification of singular points (finite and infinite) for quadratic differential systems.
ON ISOCONCENTRATION SURFACES OF THREE-DIMENSIONAL TURING PATTERNS
Authors: GLIMM TILMANN , HENTSCHEL H. G. E.
Published: April 2008

We consider three-dimensional Turing patterns and their isoconcentration surfaces corresponding to the equilibrium concentration of the reaction kinetics. We call these surfaces equilibrium concentration surfaces (EC surfaces). They are the interfaces between the regions of "high" and "low" concentrations in Turing patterns. We give alternate characterizations of EC surfaces by means of two variational principles, one of them being that they are optimal for diffusive transport. Several examples of EC surfaces are considered. Remarkably, they are often very well approximated by certain minimal surfaces. We give a dynamical explanation for the emergence of Scherk's surface in certain cases, a structure that has been observed numerically previously in [De Wit et al., 1997].
A POLYNOMIAL TIME ALGORITHM TO DETERMINE MAXIMAL BALANCED EQUIVALENCE RELATIONS
Authors: ALDIS JOHN W.
Published: April 2008

Following Golubitsky, Stewart, and others, we give definitions of networks and input trees. In order to make our work as general as possible, we work with a somewhat extended notion of multiplicity, and introduce the concept of "bunching" of trees. We then define balanced equivalence relations on networks, and a partial ordering on these relations. Previous work has shown that there is a maximal balanced equivalence relation on networks of certain classes: we provide a different style of proof which gives this result for any network. We define two algorithms to determine this relation in practice on a given finite network — one for use with networks with all multiplicities equal, and a second for the more general case. We then provide illustrative examples of each algorithm in use. We show both of these algorithms to be quartic in the size of the given network.
ON THE SPATIAL ORGANIZATION OF EPILEPTIFORM ACTIVITY
Authors: GARCÍA DOMÍNGUEZ LUIS , GUEVARA ERRA R. , WENNBERG RICHARD , PEREZ VELAZQUEZ JOSE L.
Published: April 2008

The generation and progression of epileptiform activity, especially that associated with ictal paroxysmal neuronal discharges (seizures), is usually studied in terms of its temporal evolution rather than its spatial organization. The characterization of the spatio-temporal dynamics of epileptiform activity represents a major challenge in neuroscience, due to the very intricate nature of brain structure and function. Our study is an initial attempt to reveal the structure hidden under the spatial organization of the synchronization patterns in neuronal activity associated with epilepsy. Analysis of the phase synchronization patterns from magnetoencephalographic recordings in an epileptic patient revealed a decrease in complexity during seizures. Distinct patterns of synchronized activity were observed during interictal and ictal (seizure) activity, and new tools to quantify and visualize the information contained in a synchrony pattern are proposed. The results reported here support previous observations on the high local synchronization in seizures.
STABILITY AND HOPF BIFURCATION FOR A DELAYED COOPERATIVE SYSTEM WITH DIFFUSION EFFECTS
Authors: YAN XIANG-PING , LI WAN-TONG
Published: April 2008

The main purpose of this paper is to investigate the stability and Hopf bifurcation for a delayed two-species cooperative diffusion system with Neumann boundary conditions. By linearizing the system at the positive equilibrium and analyzing the corresponding characteristic equation, the asymptotic stability of positive equilibrium and the existence of Hopf oscillations are demonstrated. It is shown that, under certain conditions, the system undergoes only a spatially homogeneous Hopf bifurcation at the positive equilibrium when the delay crosses through a sequence of critical values; under the other conditions, except for the previous spatially homogeneous Hopf bifurcations, the system also undergoes a spatially inhomogeneous Hopf bifurcation at the positive equilibrium when the delay crosses through another sequence of critical values. In particular, in order to determine the direction and stability of periodic solutions bifurcating from spatially homogeneous Hopf bifurcations, the explicit formulas are given by using the normal form theory and the center manifold reduction for partial functional differential equations (PFDEs). Finally, to verify our theoretical predictions, some numerical simulations are also included.
MULTIPLE PERIOD DOUBLING BIFURCATION ROUTE TO CHAOS IN PERIODICALLY PULSED MURALI–LAKSHMANAN–CHUA (MLC) CIRCUIT
Authors: SRINIVASAN K.
Published: April 2008

In this paper, we study the effect of additional periodic forces in Murali–Lakshmanan–Chua (MLC) circuit. We show that the additional periodic forces of pulse type display novel dynamical features including multiple period doubling bifurcation route to chaos, followed by a rich variety of dynamical phenomena including enlarged periodic windows, attractor crises, distinctly modified bifurcation structures and so on. For certain types of periodic pulses, the circuit admits transcritical bifurcations preceding the onset of multiple period doubling bifurcations. We have characterized these dynamical behaviors using Lyapunov exponents, correlation dimension, Kaplan–Yorke dimension and power spectrum, which are found to be in good agreement with the experimental observations. We have also shown that the chaotic attractor becomes more complicated and their corresponding return maps are no longer simple for large n-periodic pulses, which has immense potential applications in secure communication. The above study facilitates one to generate any desired n-period doubling bifurcation behavior by applying n-periodic pulses to a chaotic system. Further, controlling and synchronization of chaos in this periodically pulsed MLC circuit have also been achieved by using suitable methods.
PREDICTIVE CONTROL OF CONTINUOUS CHAOTIC SYSTEMS
Authors: BOUKABOU ABDELKRIM , CHEBBAH ABDELHAMID , MANSOURI NOURA
Published: April 2008

In this paper, a predictive control method is suggested for chaos control in continuous-time systems. This method combines the delayed feedback control of high order continuous-time chaotic systems with the prediction-based method of discrete-time chaotic systems. Moreover, we give necessary and sufficient conditions for exponential stabilization of unstable fixed points by the proposed method. Both control performance and system sensitivity to initial conditions of this approach are demonstrated by numerical simulations.
DETRENDED FLUCTUATION ANALYSIS OF THE US STOCK MARKET
Authors: SERLETIS APOSTOLOS , URITSKAYA OLGA YU. , URITSKY VADIM M.
Published: April 2008

This paper extends the work in [Serletis & Shintani, 2003; Elder & Serletis, 2007; Koustas et al.; Hinich & Serletis, 2008] by re-examining the empirical evidence for random walk type behavior in the US stock market. In doing so, it uses daily data on the Dow Jones Industrial Average, over the period from January 3, 1928 to March 15, 2006, and a statistical-physical approach — "detrended fluctuations analysis" — providing a reliable framework for testing the information efficiency in financial markets as shown by Uritskaya [2005a, 2005b] and Uritskaya and Uritsky [2001]. The approach eliminates nonstationary market trends and focuses on the intrinsic correlation structure of stock market fluctuations at different time scales which is studied relative to random walks models. Our results indicate that the US stock market operates close to the state predicted by the efficient markets hypothesis. The observed transient deviations from this state are shown to have a statistical origin, consistent with a purely random geometric Brownian motion.
CHARACTERIZING THE STRUCTURAL QUALITY OF GENERAL COMPLEX SOFTWARE NETWORKS
Authors: LIU JING , LÜ JINHU , HE KEQING , LI BING , TSE CHI K.
Published: April 2008

Software systems can be modeled as complex networks in which software components are abstract nodes and their interactions are abstract edges. This paper attempts to characterize the structural quality of complex software networks. We propose to use a novel statistical measure, called average propagation ratio, to characterize the structural quality of general complex software networks, such as software adaptivity and maintainability. Several real-world complex software networks are analyzed in some depth to demonstrate the application of average propagation ratios. Furthermore, we investigate the key factors that determine the average propagation ratios of general complex software networks, resulting in a set of guiding principles that can be used in practical network design for improving the structural quality of complex software systems.
Effect of ovarian suppression with gonadotropin-releasing hormone agonist on glucose disposal and insulin secretion
Authors: Toth Michael J. , Cooper Brian C. , Pratley Richard E. , Mari Andrea , Matthews Dwight E. , Casson Peter R.
Published: April 2008

Several lines of evidence suggest that ovarian hormones influence glucose homeostasis, although their exact role in humans has not been clearly defined. In the present study, we sought to test the hypothesis that ovarian hormones regulate glucose homeostasis by examining the effect of pharmacologically induced ovarian hormone deficiency on glucose disposal and insulin secretion. Young, healthy women with regular menstrual patterns were studied during the follicular and luteal phases of their cycle at baseline and after 2 mo of treatment with gonadotropin-releasing hormone agonist (GnRHa; n = 7) or placebo ( n = 6). Using hyperglycemic clamps, in combination with stable isotope-labeled (i.e.,13C and2H) glucose tracers, we measured glucose disposal and insulin secretion. Additionally, we assessed body composition and regional fat distribution using radiologic imaging techniques as well as glucoregulatory hormones. Ovarian hormone suppression with GnRHa did not alter body composition, abdominal fat distribution, or thigh tissue composition. There was no effect of ovarian suppression on total, oxidative, or nonoxidative glucose disposal expressed relative to plasma insulin level. Similarly, no effect of ovarian hormone deficiency was observed on first- or second-phase insulin secretion or insulin clearance. Finally, ovarian hormone deficiency was associated with an increase in circulating adiponectin levels but no change in leptin concentration. Our findings suggest that a brief period of ovarian hormone deficiency in young, healthy, eugonadal women does not alter glucose disposal index or insulin secretion, supporting the conclusion that ovarian hormones play a minimal role in regulating glucose homeostasis. Our data do, however, support a role for ovarian hormones in the regulation of plasma adiponectin levels.
Computational assessment of airway wall stiffness in vivo in allergically inflamed mouse models of asthma
Authors: Cojocaru Ana , Irvin Charles G. , Haverkamp Hans C. , Bates Jason H. T.
Published: April 2008

Allergic inflammation is known to cause airway hyperresponsiveness in mice. However, it is not known whether inflammation affects the stiffness of the airway wall, which would alter the load against which the circumscribing smooth muscle shortens when activated. Accordingly, we measured the time course of airway resistance immediately following intravenous methacholine injection in acutely and chronically allergically inflamed mice. We estimated the effective stiffness of the airway wall in these animals by fitting to the airway resistance profiles a computational model of a dynamically narrowing airway embedded in elastic parenchyma. Effective airway wall stiffness was estimated from the model fit and was found not to change from control in either the acute or chronic inflammatory groups. However, the acutely inflamed mice were hyperresponsive compared with controls, which we interpret as reflecting increased delivery of methacholine to the airway smooth muscle through a leaky pulmonary endothelium. These results support the notion that acutely inflamed BALB/c mice represent an animal model of functionally normal airway smooth muscle in a transiently abnormal lung.
Processing of naturally occurring sense/antisense transcripts of the vertebrate Slc34a gene into short RNAs
Authors: Carlile Mark , Nalbant Perihan , Preston-Fayers Keziah , McHaffie Gavin S. , Werner Andreas
Published: April 2008

Overlapping sense/antisense RNAs transcribed in opposite directions from the same genomic locus are common in vertebrates. The impact of antisense transcription on gene regulation and cell biology is largely unknown. We show that sense/antisense RNAs of an evolutionarily conserved phosphate transporter gene (Slc34a2a) are coexpressed in a short time window during embryonic development of zebrafish at 48 hours postfertilization (hpf). To address the mechanism by which coexpressed sense/antisense transcripts are processed, we injected sense/antisense RNAs in various combinations into Xenopus oocytes. In the cytoplasm RNAs were stable in whatever combination expressed. In the nucleus coinjected sense/antisense transcripts were degraded into short RNAs of ∼23 bases within 4 h. A homologous transcript from toad or another isoform (Slc34a2b) from zebrafish failed to trigger processing. In oocytes that were primed with nuclear sense/antisense RNA coinjections, a reporter RNA was rapidly degraded. We produced evidence that the observed processing of complementary transcripts was not restricted to Xenopus oocytes, because Slc34a-related short RNAs were detected in zebrafish embryos by Northern blotting. Signals were observed at stages that showed coexpression of sense/antisense transcripts. Remarkably, strand-specific probes revealed that the orientation of short RNAs was developmentally regulated. In addition, RNA from zebrafish embryos 48 hpf was able to induce degradation of reporter constructs in Xenopus oocytes. Our findings may give important clues to understanding the physiological role of the widespread antisense transcription.
Tobacco Smoking and Depression – Results from the WHO/ISBRA Study
Authors: Wiesbeck G.A. , Kuhl H.-C. , Yaldizli Ö. , Wurst F.M.
Published: April 2008

Aims: To elucidate the relationship between tobacco smoking and depression, and to estimate the impact of other substance dependencies. Design: Cross-sectional. Participants: A total of 1,849 men and women were interviewed face-to-face using a validated structured questionnaire. According to their tobacco smoking behavior, participants were grouped into never smokers, ex-smokers and current smokers. Measurements: Data were generated through the WHO/ISBRA study, an international multicenter study with a cross-sectional design. A standardized questionnaire was administered face-to-face by trained interviewers. Logistic regression analysis was used to predict depression. Results: There was a significant difference across the 3 smoking groups in the number of subjects who had major depression (DSM-IV) during their lifetime. The highest rate of depressives was found in current smokers (23.7%), the lowest rate in never smokers (6.2%), while the rate of those who had quit smoking (14.6%) was between both. In a logistic regression analysis, alcohol dependence (both current and during lifetime) as well as cocaine dependence were significant predictors of depression. However, the association between smoking and depression still remained statistically significant. Conclusions: This study adds support to the evidence that smoking is linked to depression. It also elucidates the importance of taking into account alcohol and cocaine dependence since they have a significant impact on the relationship between smoking and depression.
Spatial Clusters of Creutzfeldt-Jakob Disease Mortality in Japan between 1995 and 2004
Authors: Doi Y. , Yokoyama T. , Sakai M. , Nakamura Y. , Tango T. , Takahashi K.
Published: April 2008

Background: There is suggested to be a geographical difference in Creutzfeldt-Jakob disease (CJD) mortality in Japan. We performed a study to detect localized clusters and hot-spot areas of deaths from CJD in Japan during the 10-year period from 1995 to 2004. Methods: The diagnosis of CJD was taken from the death certificate (coded as A81.0 in the ICD-10). A total number of 1,168 CJD deaths (500 males and 668 females) were used for analysis using empirical Bayes estimates of standardized mortality ratios and the flexible spatial scan statistic to detect clusters. To detect the most likely cluster, p values were obtained using Monte Carlo hypothesis testing (with p < 0.05 as statistical significance).Results: The most likely cluster of CJD mortality was located in the northwest region from the base of Mt. Fuji, stretching over the two neighboring prefectures of Yamanashi and Shizuoka (relative risk = 2.28, p = 0.021). Some other clusters were detected but were not significant. Conclusions: The present study supports the evidence of geographical clustering of deaths from CJD at a specific location in Japan.
Serum Proteomic Profiling Associated with Immune System Impaired by Stress Using ProteinChip Technology
Authors: Hui Liu , Diandong Hou , Baoxia Zhao , Da Wu , Hong Yin , Xiaoyi Wu
Published: April 2008

We set out to use proteomic profiling as a means of defining serum peptides that are indicative of a stress response related to an impact on the immune system. Two types of mouse models with the immune response impaired under stress (restraint stress and thermal stress) comprised the stressed groups (n = 10 in each group), while mice without stress represented the control group (n = 10). ProteinChip technology (surface-enhanced laser desorption/ionization time-of-flight mass spectrometry) was used to investigate the serum proteomic profiles. Histopathological examination of spleens from the stressed and control groups was performed to select appropriate individuals. Compared with the spleens of normal mice, those of mice subjected to restraint and thermal stress had decreased white pulp and lymphoid nodules, and their distribution and structure changed irregularly. Pathological changes occurred in all individuals in both stressed groups. The m/z values of the protein peaks ranged from 1,500 to 50,000 daltons and were mainly in the 2,000- to 20,000-dalton range. One hundred and fifty protein peaks were detected in the three groups. Four downregulated universal stress protein peaks with m/z of 4,389, 5,341, 5,526, and 6,252 were finally selected. Unexpectedly, no upregulated universal stress protein peaks were detected. These results suggested that impairment of the immune system results from inhibition of growth-promoting factors associated with the immune system. Identified protein peaks may be biomarkers of the impaired immune system under stress.
Cardiothoracic Ratio, Malnutrition, Inflammation, and Two-Year Mortality in Non-Diabetic Patients on Maintenance Hemodialysis
Authors: Chen Kuan-Hsing , Lin-Tan Dan-Tzu , Huang Wen-Hung , Hung Cheng-Chieh , Chang Chiz-Tzung , Huang Jeng-Yi , Lin Ja-Liang
Published: April 2008

Background/Aims: Cardiothoracic ratio (CTR) is associated with left ventricular mass, left ventricular systolic dysfunction and mortality in patients with hypertension or chronic cardiovascular disease. The clinical significance of CTR in non-diabetic maintenance hemodialysis (MHD) patients remains unclear. Methods: 468 non-diabetic MHD patients were enrolled. Geographic, hematological, biochemical and dialysis-related data were obtained. The patients were analyzed for nutritional and inflammatory markers as well as CTR. All patients were followed up for 2 years to investigate the risks for mortality. Results: Chi-square analysis showed that the incidence of malnutrition and inflammation was significantly higher in patients with CTR >60% than in patients with CTR ≤60%. CTR positively correlated with high-sensitivity C-reactive protein (hsCRP) levels but negatively correlated with albumin levels. 29 patients (6.2%) had expired by the end of the study. Cox multivariate analysis revealed that CTR significantly predicts both all-cause and cardiovascular-cause 2-year mortality in non-diabetic MHD patients. Conclusion: CTR is an indicator of inflammation and nutritional status in non-diabetic MHD patients and can predict 2-year mortality in these patients. The analytical results of this study support continued efforts to reduce CTR and treat underlying causes in patients with CTR >50%.
Organic Elemental Composition in Fingernail Plates Varies between Sexes and Changes with Increasing Age in Healthy Humans
Authors: Dittmar Manuela , Dindorf Willi , Banerjee Arun
Published: April 2008

Background: Keratin, an α-helical fibrous protein, is the primary component of human nail plates. No data on age-related changes in healthy subjects are present. Objective: This study investigated whether keratin amount and composition, as indicated by organic elemental composition of fingernails, varies with aging and between sexes. Methods: Nail clippings from 225 healthy individuals (93 males, 132 females), aged 20–90 years, were analyzed for carbon (C), nitrogen (N), and sulfur (S) contents with an automatic elemental analyzer. C/N and N/S ratios were calculated. The C/N ratio is indicative of keratin composition, i.e. the ratio of α-amino acids and protein. The relationship of elemental composition with dietary intake was analyzed by standardized food record. Results: Females have in their nails more sulfur (p < 0.001) and less nitrogen (p = 0.001), and thereby, a lower N/S ratio than males, whereas their carbon content is not different. With aging, the carbon content increases (p < 0.01, both sexes) and the nitrogen content decreases (p = 0.05, females), both leading to an increased C/N ratio (p < 0.001). By contrast, the sulfur content and the N/S ratio do not change with aging (p > 0.05). The carbon content correlates positively with macronutrient intake in females. Nitrogen and sulfur contents are not related with dietary intake. Conclusions: Results suggest that the N/S ratio is indicative of sex differences and the C/N ratio of aging in healthy humans. The increasing carbon content with ongoing age could be explained by loss of inorganic material from the nails, followed by a subsequent increase of organic material. The increasing C/N ratio gives evidence that keratin composition changes towards a higher amount of α-amino acids with aging.
Combining Modalities with Different Latencies for Optimal Motor Control
Authors: Bissmarck Fredrik , Nakahara Hiroyuki , Doya Kenji , Hikosaka Okihide
Published: April 2008

Feedback signals may be of different modality, latency, and accuracy. To learn and control motor tasks, the feedback available may be redundant, and it would not be necessary to rely on every accessible feedback loop. Which feedback loops should then be utilized? In this article, we propose that the latency is a critical factor to determine which signals will be influential at different learning stages. We use a computational framework to study the role of feedback modules with different latencies in optimal motor control. Instead of explicit gating between modules, the reinforcement learning algorithm learns to rely on the more useful module. We tested our paradigm for two different implementations, which confirmed our hypothesis. In the first, we examined how feedback latency affects the competitiveness of two identical modules. In the second, we examined an example of visuomotor sequence learning, where a plastic, faster somatosensory module interacts with a preacquired, slower visual module. We found that the overall performance depended on the latency of the faster module alone, whereas the relative latency determines the independence of the faster from the slower. In the second implementation, the somatosensory module with shorter latency overtook the slower visual module, and realized better overall performance. The visual module played different roles in early and late learning. First, it worked as a guide for the exploration of the somatosensory module. Then, when learning had converged, it contributed to robustness against system noise and external perturbations. Overall, these results demonstrate that our framework successfully learns to utilize the most useful available feedback for optimal control.
Two Neurocognitive Mechanisms of Semantic Integration during the Comprehension of Visual Real-world Events
Authors: Sitnikova Tatiana , Holcomb Phillip J. , Kiyonaga Kristi A. , Kuperberg Gina R.
Published: April 2008

How do comprehenders build up overall meaning representations of visual real-world events? This question was examined by recording event-related potentials (ERPs) while participants viewed short, silent movie clips depicting everyday events. In two experiments, it was demonstrated that presentation of the contextually inappropriate information in the movie endings evoked an anterior negativity. This effect was similar to the N400 component whose amplitude has been previously reported to inversely correlate with the strength of semantic relationship between the context and the eliciting stimulus in word and static picture paradigms. However, a second, somewhat later, ERP component—a posterior late positivity—was evoked specifically when target objects presented in the movie endings violated goal-related requirements of the action constrained by the scenario context (e.g., an electric iron that does not have a sharp-enough edge was used in place of a knife in a cutting bread scenario context). These findings suggest that comprehension of the visual real world might be mediated by two neurophysiologically distinct semantic integration mechanisms. The first mechanism, reflected by the anterior N400-like negativity, maps the incoming information onto the connections of various strengths between concepts in semantic memory. The second mechanism, reflected by the posterior late positivity, evaluates the incoming information against the discrete requirements of real-world actions. We suggest that there may be a tradeoff between these mechanisms in their utility for integrating across people, objects, and actions during event comprehension, in which the first mechanism is better suited for familiar situations, and the second mechanism is better suited for novel situations.
Action Co-representation is Tuned to Other Humans
Authors: Tsai Chia-Chin , Kuo Wen-Jui , Hung Daisy L. , Tzeng Ovid J. L.
Published: April 2008

The present study attempts to explore the process by which knowledge of another's intentional behavior in a joint-action scenario is represented through the action observation and execution network—also known as the common coding system. Participants (n = 18) were instructed to perform the complementary social Simon task under the implemented belief of interaction with either an unseen human (biological agent) or a computer program, where in fact, all response sequences from either “partner” were generated by computer. Results provide behavioral and neurophysiological evidence (P3 and S-LRP) that the believed intentionality of another person's actions is sufficient to facilitate a strong-enough agency-dependent social Simon effect to modulate action planning and anticipation. We suggest that the co-representation of human action may be an evolved biologically tuned default of the human motor system.
From High Hopes to Disillusionment: Indigenous Peoples' Struggle to (re)Gain Their Right to Self-determination
Authors: Koivurova Timo
Published: April 2008

This article will examine three international processes wherein the right to self-determination of indigenous peoples has been taken up: the process whereby the United Nations (UN) General Assembly adopted the UN Declaration on the Rights of Indigenous Peoples (UN Declaration), the intention to negotiate a Nordic Saami Convention (Draft Convention) and the practice of the Human Rights Committee (HRC) in monitoring the observance of the International Covenant on Civil and Political Rights (Covenant). All of these processes have enunciated indigenous peoples' right to self-determination, but any claim to such a right has met with resistance from the states, with the reasons for such resistance examined here. The aim is to study why it is so difficult to insert indigenous peoples into international law as category and, in particular, to have states accept their right to self-determination. In the conclusions, it is useful to ask whether the problems experienced in promoting the right to self-determination of indigenous peoples are mere setbacks or whether they contain elements that might inform the international movement of indigenous peoples more generally.
Cicero de Oratore 2.51-64 and Rhetoric in Historiography
Authors:   Northwood
Published: April 2008

An analysis of Cicero's vocabulary, argumentation, and views on Greek historians in de Orat. 2.51-8 shows that he criticizes the early Roman historians for failings in both style and content. This contradicts A.J. Woodman's claim that the views of Cicero's 'Antonius' have “nothing to do with style”. Furthermore the idea that Cicero considered the exaedificatio of an historical work not to be subject to the leges historiae is based on a mistaken interpretation of de Orat. 2.63. It is argued that this text provides no theoretical foundation for a “hard core” of material subject to the leges historiae and a “superstructure” subject only to the rhetorical requirement of plausibility.
Intercultural Dialogue — An Overrated Means of Acquiring Understanding Examined in the Context of Christian Mission to Africa
Authors: Harries Jim
Published: April 2008

Intercultural dialogue is at depth impossible, because mutual understanding is only possible in so far as cultures and languages used are common, and not different. Assuming the wrong topic of conversation will result in a realisation of error and not productive progress. Having a common language (such as English) alone does not bring mutual understanding because languages are integrally rooted in cultures. Conversations always being engaged with a view to potential and actual overhearers of all sorts, means that mutual understanding requires a clear knowledge of overhearers on both sides. Power issues and types of reasoning often being in the context and not the content of dialogue means that failure to realise the context from which someone is dialoguing is in effect misunderstanding.
Probabilistic Forecasts from the National Digital Forecast Database
Authors: Krzysztofowicz Roman , Evans W. Britt
Published: April 2008

The Bayesian processor of forecast (BPF) is developed for a continuous predictand. Its purpose is to process a deterministic forecast (a point estimate of the predictand) into a probabilistic forecast (a distribution function, a density function, and a quantile function). The quantification of uncertainty is accomplished via Bayes theorem by extracting and fusing two kinds of information from two different sources: (i) a long sample of the predictand from the National Climatic Data Center, and (ii) a short sample of the official National Weather Service forecast from the National Digital Forecast Database. The official forecast is deterministic and hence deficient: it contains no information about uncertainty. The BPF remedies this deficiency by outputting the complete and well-calibrated characterization of uncertainty needed by decision makers and information providers. The BPF comes furnished with (i) the meta-Gaussian model, which fits meteorological data well as it allows all forms of marginal distribution functions, and nonlinear and heteroscedastic dependence structures, and (ii) the statistical procedures for estimation of parameters from asymmetric samples and for coping with nonstationarities in the predictand and the forecast due to the annual cycle and the lead time. A comprehensive illustration of the BPF is reported for forecasts of the daily maximum temperature issued with lead times of 1, 4, and 7 days for three stations in two seasons (cool and warm).
Fate of Internal Mammary Artery Grafted to Left Anterior Descending Artery is Influenced by Native Vessel Stenosis and Viable Myocardium
Authors: Yilmaz Mehmet B. , Guray Yesim , Altay Hakan , Demirkan Burcu , Caldir Vedat , Guray Umit , Biyikoglu Senay F. , Sasmaz Hatice , Kisacik Halil L. , Korkmaz Sule
Published: April 2008

In this study, factors leading to the failure of internal mammary artery grafting was investigated among patients with coronary bypass. In all, 1323 patients were evaluated. It was found that lower grade diameter stenosis in the native vessel during postoperative angiogram and wall motion score index independently affected the fate of internal mammary artery as a graft. Grafting with internal mammary artery to native vessels with lower grade stenosis and to myocardium with poor wall score might not be a rational approach.
China as Viewed by Two Early Bengali Travellers
Authors: Sen Narayan C.
Published: April 2008

The writings of Indian travellers in Republican China have attracted limited attention. This article examines the travel accounts of two Bengali travellers who visited China in the early twentieth century. Indumadhav Mullick may have been the earliest Bengali to write an eyewitness account of China for Bengali readers in India. Mullick's account is noteworthy for its vivid record of the maritime route from the eastern coast of India to China and his descriptions of the southern Chinese port, Xiamen. Benoy Kumar Sarkar, on the other hand, provides detailed observations about the political situation in China and the vibrant intellectual life in Shanghai. Together these two works are important for understanding the interactions between India and China during the colonial period. They are also vital for examining the cultural links between Kolkata and China during the early twentieth century.
Undermine, or Bring Them Over: SOE and OSS Plans for Hungary in 1943
Authors: Meszerics Tamás
Published: April 2008

Plans for British and American political warfare operations in 1943 diverged considerably. SOE conceptions always involved a sabotage component, while OSS naturally put more emphasis on intelligence requirements. Detaching Hungary from the Axis became a strategic goal almost only by chance. Operational plans were not as fully responsive to shifts in Allied strategy as one might have expected. Assumptions about Allied military presence in the Balkans remained part of the plans far beyond the decisions reached at Quadrant.
'Good Morning, Pupil!' American Representations of Italianness and the Occupation of Italy, 1943—1945
Authors: Buchanan Andrew
Published: April 2008

Popular American images of Italianness before and during the second world war represented Italians as an infantile, emotional and largely apolitical people whose character was marked by cowardice and unpredictable violence. Unlike the German and Japanese peoples, who, by dint of their inherent militarism or their racialized religious allegiance to their 'god-emperor', were judged complicit in the policies of their governments, Italians were presented as the hapless victims of fascism. This construction enabled the place and significance of America's war with Italy to be systematically underemphasized and, more importantly, it allowed the Allied occupation of Italy to be framed from the beginning as an exercise in humanitarian redemption. This article examines the relationship between American representations of Italianness in films, novels and the news media, and the actuality of the Allied occupation, and contrasts it with the experience of the occupations of Germany and Japan.
The Cult of the Red Martyr: Politics of Commemoration in China
Authors: Hung Chang-tai
Published: April 2008

Facing an increasing number of deaths among its rank and file in the wars against Japan and the Kuomintang (Nationalists), the Chinese Communist Party (CCP) began to promote the cult of the red martyr during the late Yan'an era, and then developed it in a systematic fashion after the founding of the People's Republic of China in 1949. In the 1950s, the CCP cultivated the cult to honour those who had died in the revolution with commemorative practices such as the launching of the Martyrs' Memorial Day and the building of a national cemetery — the Babaoshan Revolutionary Cemetery — in the western part of Beijing as a place of national pilgrimage. The cult served the purposes of diverting attention from the destruction of war, justifying armed conflict as a means to fight enemies, providing psychological comfort for the bereaved, and, finally, educating future generations about socialist goals, serving, in the words of Zhou Enlai, 'to commemorate the dead and inspire the living'. However, the CCP's political aims did not always dominate how the cult was interpreted, for the bereaved often expressed less political and more emotional views about their grief and personal loss. In recent years, as revolutionary fervour wanes and material gains have come to dominate the lives of the Chinese people, war memorials have fallen into oblivion. The cult is rapidly losing its influence, and, with that, the Party's ability to control its people is deteriorating.
Political Purges and State Crisis in Portugal's Transition to Democracy, 1975—76
Authors: Pinto António Costa
Published: April 2008

The Portuguese military coup of 25 April 1974 was the beginning of the 'third wave' of democratic transitions in Southern Europe. Unshackled by international pro-democratizing forces and occurring in the midst of the Cold War, the coup led to a severe crisis of the state that was aggravated by the simultaneous processes of transition to democracy and de-colonization of what was the last European colonial empire. This article analyses how Portugal's political élite and society struggled with two aspects of the authoritarian legacies of the 'Estado Novo' during the transition: the élite and the institutions associated with the dictatorship. The nature of the Portuguese transition and the consequent state crises created a 'window of opportunity' in which the 'reaction to the past' was much stronger in Portugal than in the other Southern European transitions. In fact, the transition's powerful dynamic in itself served to constitute a legacy for the consolidation of democracy.
Community Violence, Interpartner Conflict, Parenting, and Social Support as Predictors of the Social Competence of African American Preschool Children
Authors: Oravecz Linda M. , Koblinsky Sally A. , Randolph Suzanne M.
Published: April 2008

Adopting an ecological framework, this study examines the role of community violence exposure, interpartner conflict, positive parenting, and informal social support in predicting the social skills and behavior problems of low-income African American preschoolers. Participants were 184 African American mothers and female caregivers of Head Start children who completed study measures in a structured interview. Regression analyses revealed that greater community violence exposure predicted more internalizing and externalizing child behavior problems and lower levels of self-control and cooperation. Greater interpartner conflict predicted more internalizing problems. Positive parenting was predictive of fewer internalizing and externalizing problems and higher levels of child self-control and cooperation. Greater informal social support predicted higher levels of all four child social skills, including self-control, cooperation, assertion, and responsibility. Positive parenting and informal social support failed to moderate the relationships between community violence exposure and interpartner conflict and child outcomes. Implications of the findings for intervention and future research are discussed.
The Social Foundation of Religious Meaning in Life
Authors: Krause Neal
Published: April 2008

The purpose of this study was to see whether informal social support from fellow church members sustains an older person's sense of religious meaning in life over time. Two types of church-based social support were evaluated: spiritual support and emotional support. Data from a nationwide longitudinal survey of older adults suggested that both emotional and spiritual support tend to sustain a sense of religious meaning in life, but of the two, spiritual support appeared to exert the greatest effect. The findings further revealed that older African Americans are more likely than older European Americans to derive a sense of meaning in life through religion. This race difference is largely explained by the fact that older African Americans tend to receive more church-based social support than older European Americans.
Organizational Citizenship Behavior of Temporary Knowledge Employees
Authors: Blatt Ruth
Published: April 2008

This study examines accounts of organizational citizenship behavior (OCB) by temporary knowledge employees. Most studies of OCB are based on the perspective of permanent employees and may not account for the unique perspective of temporary knowledge employees. This study finds that the most prominent themes in temporary knowledge employees' explanations for why they engaged in OCB are their perceived norms of professional behavior for their occupation and an experience of positive regard with and among their co-workers. This is in contrast with the themes of social exchange, organizational identification, and impression management that are currently invoked in explaining OCBs among permanent employees.