bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypertension and disrupted blood pressure circadian rhythm in Type 2 diabetic db/db mice
Authors: Su Wen , Guo Zhenheng , Randall David C. , Cassis Lisa , Brown David R. , Gong Ming C.
Published: August 2008

Human Type 2 diabetes is associated with increased incidence of hypertension and disrupted blood pressure (BP) circadian rhythm. Db/db mice have been used extensively as a model of Type 2 diabetes, but their BP is not well characterized. In this study, we used radiotelemetry to define BP and the circadian rhythm in db/db mice. We found that the systolic, diastolic, and mean arterial pressures were each significantly increased by 11, 8, and 9 mmHg in db/db mice compared with controls. In contrast, no difference was observed in pulse pressure or heart rate. Interestingly, both the length of time db/db mice were active (locomotor) and the intensity of locomotor activity were significantly decreased in db/db mice. In contrast to controls, the 12-h light period average BP in db/db mice did not dip significantly from the 12-h dark period. A partial Fourier analysis of the continuous 72-h BP data revealed that the power and the amplitude of the 24-h period length rhythm were significantly decreased in db/db mice compared with the controls. The acrophase was centered at 0141 in control mice, but became scattered from 1805 to 0236 in db/db mice. In addition to BP, the circadian rhythms of heart rate and locomotor activity were also disrupted in db/db mice. The mean arterial pressure during the light period correlates with plasma glucose, insulin, and body weight. Moreover, the oscillations of the clock genes DBP and Bmal1 but not Per1 were significantly dampened in db/db mouse aorta compared with controls. In summary, our data show that db/db mice are hypertensive with a disrupted BP, heart rate, and locomotor circadian rhythm. Such changes are associated with dampened oscillations of clock genes DBP and Bmal1 in vasculature.
Regulation of cardiac myocyte contractility by phospholemman: Na+/Ca2+ exchange versus Na+-K+-ATPase
Authors: Song Jianliang , Zhang Xue-Qian , Wang JuFang , Cheskis Ellina , Chan Tung O. , Feldman Arthur M. , Tucker Amy L. , Cheung Joseph Y.
Published: August 2008

Phospholemman (PLM) regulates cardiac Na+/Ca2+ exchanger (NCX1) and Na+-K+-ATPase in cardiac myocytes. PLM, when phosphorylated at Ser68, disinhibits Na+-K+-ATPase but inhibits NCX1. PLM regulates cardiac contractility by modulating Na+-K+-ATPase and/or NCX1. In this study, we first demonstrated that adult mouse cardiac myocytes cultured for 48 h had normal surface membrane areas, t-tubules, and NCX1 and sarco(endo)plasmic reticulum Ca2+-ATPase levels, and retained near normal contractility, but α1-subunit of Na+-K+-ATPase was slightly decreased. Differences in contractility between myocytes isolated from wild-type (WT) and PLM knockout (KO) hearts were preserved after 48 h of culture. Infection with adenovirus expressing green fluorescent protein (GFP) did not affect contractility at 48 h. When WT PLM was overexpressed in PLM KO myocytes, contractility and cytosolic Ca2+ concentration ([Ca2+]i) transients reverted back to those observed in cultured WT myocytes. Both Na+-K+-ATPase current ( Ipump) and Na+/Ca2+ exchange current ( INaCa) in PLM KO myocytes rescued with WT PLM were depressed compared with PLM KO myocytes. Overexpressing the PLMS68E mutant (phosphomimetic) in PLM KO myocytes resulted in the suppression of INaCa but had no effect on Ipump. Contractility, [Ca2+]i transient amplitudes, and sarcoplasmic reticulum Ca2+ contents in PLM KO myocytes overexpressing the PLMS68E mutant were depressed compared with PLM KO myocytes overexpressing GFP. Overexpressing the PLMS68A mutant (mimicking unphosphorylated PLM) in PLM KO myocytes had no effect on INaCa but decreased Ipump. Contractility, [Ca2+]i transient amplitudes, and sarcoplasmic reticulum Ca2+ contents in PLM KO myocytes overexpressing the S68A mutant were similar to PLM KO myocytes overexpressing GFP. We conclude that at the single-myocyte level, PLM affects cardiac contractility and [Ca2+]i homeostasis primarily by its direct inhibitory effects on Na+/Ca2+ exchange.
Venous response to orthostatic stress
Authors: Krabbendam Ineke , Jacobs Loes C. A. , Lotgering Fred K. , Spaanderman Marc E. A.
Published: August 2008

Head-up tilt (HUT) induces a reduction in preload, which is thought to be restored through sympathetic venoconstriction, reducing unstressed volume (Vu) and venous compliance (VeC). In this study, we assessed venous inflow and outflow responses and their reproducibility and determined the relation with autonomic function during HUT. Eight healthy non-pregnant women were subjected to 20° head-down tilt to 60° HUT at 20° intervals. At each rotational step, we randomly assessed forearm pressure-volume (P-V) curves (venous occlusion plethysmography) during inflow (VeCIN) and outflow [venous emptying rate (VEROUT)]. VeCIN was defined as the ratio of the slope of the volume-time curve and pressure-time curve, with direct intravenous pressure measurement. VEROUT was determined using the derivate of a quadratic regression model using cuff pressure. We defined Vu as the y-intercept of the P-V curve. We calculated, for both methods, the coefficients of reproducibility (CR) and variation (CV). Vascular sympathetic activity was determined by spectral analysis. VeCIN decreased at each rotational step compared with the supine position ( P < 0.05), whereas VEROUT increased. CR of VeCIN was higher in the supine position than VEROUT but lower during HUT. CV varied between 19% and 25% (VeCIN) and between 12% and 21% (VEROUT). HUT decreased Vu. The change in VeCIN and VEROUT correlated with the change in vascular sympathetic activity ( r = −0.36, P < 0.01, and r = 0.48, P < 0.01). This is the first study in which a reproducible reduction in VeCIN and Vu and a rise in VEROUT during HUT are documented. The alterations in venous characteristics relate to changes in vascular sympathetic activity.
Internalization of eNOS via caveolae regulates PAF-induced inflammatory hyperpermeability to macromolecules
Authors: Sánchez Fabiola A. , Kim David D. , Durán Ricardo G. , Meininger Cynthia J. , Durán Walter N.
Published: August 2008

Endothelial nitric oxide (NO) synthase (eNOS) is thought to regulate microvascular permeability via NO production. We tested the hypotheses that the expression of eNOS and eNOS endocytosis by caveolae are fundamental for appropriate signaling mechanisms in inflammatory endothelial permeability to macromolecules. We used bovine coronary postcapillary venular endothelial cells (CVECs) because these cells are derived from the microvascular segment responsible for the transport of macromolecules in inflammation. We stimulated CVECs with platelet-activating factor (PAF) at 100 nM and measured eNOS phosphorylation, NO production, and CVEC monolayer permeability to FITC-dextran 70 KDa (Dx-70). PAF translocated eNOS from plasma membrane to cytosol, induced changes in the phosphorylation state of the enzyme, and increased NO production from 4.3 ± 3.8 to 467 ± 22.6 nM. PAF elevated CVEC monolayer permeability to FITC-Dx-70 from 3.4 ± 0.3 × 10−6 to 8.5 ± 0.4 × 10−6 cm/s. The depletion of endogenous eNOS with small interfering RNA abolished PAF-induced hyperpermeability, demonstrating that the expression of eNOS is required for inflammatory hyperpermeability responses. The inhibition of the caveolar internalization by blocking caveolar scission using transfection of dynamin dominant-negative mutant, dyn2K44A, inhibited PAF-induced hyperpermeability to FITC-Dx-70. We interpret these data as evidence that 1) eNOS is required for hyperpermeability to macromolecules and 2) the internalization of eNOS via caveolae is an important mechanism in the regulation of endothelial permeability. We advance the novel concept that eNOS internalization to cytosol is a signaling mechanism for the onset of microvascular hyperpermeability in inflammation.
The impact of baseline diameter on flow-mediated dilation differs in young and older humans
Authors: Thijssen Dick H. J. , van Bemmel Marieke M. , Bullens Lauren M. , Dawson Ellen A. , Hopkins Nicola D. , Tinken Toni M. , Black Mark A. , Hopman Maria T. E. , Cable N. Timothy , Green Daniel J.
Published: August 2008

Flow-mediated dilation (FMD) has become a commonly applied approach for the assessment of vascular function and health, but methods used to calculate FMD differ between studies. For example, the baseline diameter used as a benchmark is sometimes assessed before cuff inflation, whereas others use the diameter during cuff inflation. Therefore, we compared the brachial artery diameter before and during cuff inflation and calculated the resulting FMD in healthy children ( n = 45; 10 ± 1 yr), adults ( n = 31; 28 ± 6 yr), and older subjects ( n = 22; 58 ± 5 yr). Brachial artery FMD was examined after 5 min of distal ischemia. Diameter was determined from either 30 s before cuff inflation or from the last 30 s during cuff inflation. Edge detection and wall tracking of high resolution B-mode arterial ultrasound images was used to calculate conduit artery diameter. Brachial artery diameter during cuff inflation was significantly larger than before inflation in children ( P = 0.02) and adults ( P < 0.001) but not in older subjects ( P = 0.59). Accordingly, FMD values significantly differed in children (11.2 ± 5.1% vs. 9.4 ± 5.2%; P = 0.02) and adults (7.3 ± 3.2% vs. 4.6 ± 3.3%; P < 0.001) but not in older subjects (6.3 ± 3.4% vs. 6.0 ± 4.2%; P = 0.77). When the diameter before cuff inflation was used, an age-dependent decline was evident in FMD, whereas FMD calculated using the diameter during inflation was associated with higher FMD values in older than younger adults. In summary, the inflation of the cuff significantly increases brachial artery diameter, which results in a lower FMD response. This effect was found to be age dependent, which emphasizes the importance of using appropriate methodology to calculate the FMD.
Regulating RISK: a role for JAK-STAT signaling in postconditioning?
Authors: Goodman Michael D. , Koch Sheryl E. , Fuller-Bicer Geraldine A. , Butler Karyn L.
Published: August 2008

Postconditioning (POC), a novel strategy of cardioprotection against ischemia-reperfusion injury, is clinically attractive because of its therapeutic application at the predictable onset of reperfusion. POC activates several intracellular kinase signaling pathways, including phosphatidylinositol 3-kinase (PI3K)-Akt (RISK). The regulation of POC-induced survival kinase signaling, however, has not been fully characterized. JAK-STAT activation is integral to cardiac ischemic tolerance and may provide upstream regulation of RISK. We hypothesized that POC requires the activation of both JAK-STAT and RISK signaling. Langendorff-perfused mouse hearts were subjected to 30 min of global ischemia and 40 min of reperfusion, with or without POC immediately after ischemia. A separate group of POC hearts was treated with AG 490, a JAK2 inhibitor, Stattic, a specific STAT3 inhibitor, or LY-294002, a PI3K inhibitor, at the onset of reperfusion. Cardiomyocyte-specific STAT3 knockout (KO) hearts were also subjected to non-POC or POC protocols. Myocardial performance (+dP/d tmax, mmHg/s) was assessed throughout each perfusion protocol. Phosphorylated (p-) STAT3 and Akt expression was analyzed by Western immunoblotting. POC enhanced myocardial functional recovery and increased expression of p-STAT3 and p-Akt. JAK-STAT inhibition abrogated POC-induced functional protection. STAT3 inhibition decreased expression of both p-STAT3 and p-Akt. PI3K inhibition also attenuated POC-induced cardioprotection and reduced p-Akt expression but had no effect on STAT3 phosphorylation. Interestingly, STAT3 KO hearts undergoing POC exhibited improved ischemic tolerance compared with KO non-POC hearts. POC induces myocardial functional protection by activating the RISK pathway. JAK-STAT signaling, however, is insufficient for effective POC without PI3K-Akt activation.
Polarity reversal lowers activation time during diastolic field stimulation of the rabbit ventricles: insights into mechanisms
Authors: Maleckar M. M. , Woods M. C. , Sidorov V. Y. , Holcomb M. R. , Mashburn D. N. , Wikswo J. P. , Trayanova N. A.
Published: August 2008

To fully characterize the mechanisms of defibrillation, it is necessary to understand the response, within the three-dimensional (3D) volume of the ventricles, to shocks given in diastole. Studies that have examined diastolic responses conducted measurements on the epicardium or on a transmural surface of the left ventricular (LV) wall only. The goal of this study was to use optical imaging experiments and 3D bidomain simulations, including a model of optical mapping, to ascertain the shock-induced virtual electrode and activation patterns throughout the rabbit ventricles following diastolic shocks. We tested the hypothesis that the locations of shock-induced regions of hyperpolarization govern the different diastolic activation patterns for shocks of reversed polarity. In model and experiment, uniform-field monophasic shocks of reversed polarities (cathode over the right ventricle is RV−, reverse polarity is LV−) were applied to the ventricles in diastole. Experiments and simulations revealed that RV− shocks resulted in longer activation times compared with LV− shocks of the same strength. 3D simulations demonstrated that RV− shocks induced a greater volume of hyperpolarization at shock end compared with LV− shocks; most of these hyperpolarized regions were located in the LV. The results of this study indicate that ventricular geometry plays an important role in both the location and size of the shock-induced virtual anodes that determine activation delay during the shock and subsequently affect shock-induced propagation. If regions of hyperpolarization that develop during the shock are sufficiently large, activation delay may persist until shock end.
Morphological and biochemical characterization of basal and starvation-induced autophagy in isolated adult rat cardiomyocytes
Authors: Maruyama Rumi , Goto Kazuko , Takemura Genzou , Ono Koh , Nagao Kazuya , Horie Takahiro , Tsujimoto Akiko , Kanamori Hiromitsu , Miyata Shusaku , Ushikoshi Hiroaki , Nagashima Kenshi , Minatoguchi Shinya , Fujiwara Takako , Fujiwara Hisayoshi
Published: August 2008

Autophagy is simultaneously a mode of programmed cell death and an important physiological process for cell survival, but its pathophysiological significance in cardiac myocytes remains largely unknown. We induced autophagy in isolated adult rat ventricular cardiomyocytes (ARVCs) by incubating them in glucose-free, mannitol-supplemented medium for up to 4 days. Ultrastructurally, intracellular vacuoles containing degenerated subcellular organelles (e.g., mitochondria) were markedly apparent in the glucose-starved cells. Microtubule-associated protein-1 light chain 3 was significantly upregulated among the glucose-starved ARVCs than among the controls. After 4 days, glucose-starved ARVCs showed a significantly worse survival rate (19 ± 5.2%) than the controls (55 ± 8.3%, P < 0.005). Most dead ARVCs in both groups showed features of necrosis, and the rate of apoptosis did not differ between the groups. Two inhibitors of autophagy, 3-methyladenine (3-MA) and leupeptin, significantly and dose-dependently reduced the viability of both control and glucose-starved ARVCs and caused specific morphological alterations; 3-MA reduced autophagic findings, whereas leupeptin greatly increased the numbers and the sizes of vacuoles that contained incompletely digested organelles. The knockdown of the autophagy-related genes with small interfering RNA also reduced the glucose-starved ARVCs viability, but rapamycin, an autophagy enhancer, improved it. Reductions in the ATP content of ARVCs caused by glucose depletion were exacerbated by the inhibitors while attenuated by rapamycin, suggesting that autophagy inhibition might accelerate energy depletion, leading to necrosis. Taken together, our findings suggest that autophagy in cardiomyocytes reflects a prosurvival, compensatory response to stress and that autophagic cardiomyocyte death represents an unsuccessful outcome due to necrosis.
Physiological Basis of Limb-Impedance Modulation During Free and Constrained Movements
Authors: Damm Loïc , McIntyre Joseph
Published: August 2008

Arm stiffness is a critical factor underlying stable interactions with the environment. When the hand moves freely through space, a stiff limb would most effectively maintain the hand on the desired path in the face of external perturbations. Conversely, when constrained by a rigid surface, a compliant limb would allow the surface to guide the hand while minimizing variations in contact forces. We aimed to identify the physiological basis of stiffness adaptation for these two classes of movement. Stiffness can be regulated by two mechanisms: coactivation of antagonistic muscles and modulation of reflex gains. We hypothesized that subjects would select high stiffness (high coactivation and/or reflex gains) in free space and high compliance (low coactivation and reflex gains) for constrained movements. We measured EMG and the H-reflex during constrained and unconstrained movement of the wrist. As predicted, subjects coactivated antagonist muscles more when performing the unconstrained movement. Contrary to our hypothesis, however, H-reflex amplitude was higher for the constrained movement despite the a priori preference for lower reflex gains in this situation. In addition, the H-reflex depended on the task and the net force exerted by the limb on the environment, rather than showing a simple dependence on the level of muscle activation. Thus stiffness seems to increase in free space compared with constrained motion through the use of coactivation, whereas spinal loop gains are adjusted to better regulate the influence of afferences on the ongoing movement. These observations support the hypothesis of movement programming in terms of impedance.
Locoregionally Advanced Nasopharyngeal Carcinoma: Induction Chemotherapy with Cisplatin and 5-Fluorouracil Followed by Radiotherapy and Concurrent Cisplatin
Authors: Ferrari D. , Chiesa F. , Codecà C. , Calabrese L. , Jereczek-Fossa B.A. , Alterio D. , Fiore J. , Luciani A. , Floriani I. , Orecchia R. , Foa P.
Published: August 2008

Background: Chemoradiotherapy is the current standard of care for locoregionally advanced nasopharyngeal carcinoma. The purpose of this study was to assess the feasibility and efficacy of induction chemotherapy (CHT) followed by concomitant chemoradiotherapy in this patient population. Patients and Methods: In this single-arm, phase II study, patients with locoregionally advanced nasopharyngeal carcinoma were treated with 3 cycles of induction CHT with cisplatin (100 mg/m2 on day 1) and 5-fluorouracil (1,000 mg/m2 continuous infusion on days 1–4) followed by 3 cycles of cisplatin (100 mg/m2 on days 1, 22 and 43) and concurrent radiotherapy up to 70 Gy. The primary endpoint was objective response. Results: Thirty-four patients were enrolled, and all completed both induction treatment and subsequent chemoradiotherapy. Objective response rates were 79.4% (95% CI 62.1–91.3) and 85.3% (95% CI 68.9–95.0) after induction CHT and chemoradiation, respectively. Treatment was well tolerated and toxicity was manageable. At a median follow-up of 29 months, 3-year overall survival and progression-free survival rates are 80.0% (95% CI 0.64–0.95) and 54.0% (95% CI 0.36–0.73), respectively. Conclusions: Induction CHT with cisplatin and 5-fluorouracil followed by concomitant chemoradiotherapy is a feasible and active regimen for patients with stage IIB–IVB nasopharyngeal carcinoma. This regimen resulted in excellent locoregional disease control and overall survival.
Feminist social work research engaging with poststructural ideas
Authors: Wendt Sarah , Boylan Jane
Published: August 2008

English

This article draws on two empirical studies, one with women who had experienced domestic violence and the other with children and young people in public care. It presents reflections by two feminist social workers on how poststructuralism influenced their research practices in social work.

French

Cet article fait appel à deux études empiriques; la première auprès de femmes victimes de violence conjugale et la seconde auprès d'enfants et d'adolescents pris en charge par les services sociaux. Il présente les réflexions de deux travailleuses sociales féministes sur la façon dont le poststructuralisme a influencé leurs recherches en travail social.

Spanish

Este artículo llama la atención sobre dos estudios empíricos, uno con mujeres que tuvieron experiencias de violencia doméstica y el otro con niños y gente joven con cuidados públicos. Presenta reflexiones de dos trabajadoras sociales feministas, sobre cómo el post-estructuralismo ha influenciado sus prácticas de investigación en trabajo social.
A reflection on the indigenization discourse in social work
Authors: Huang Yunong  , Zhang Xiong
Published: August 2008

English

This article gives a brief review of the indigenization discourse in social sciences and in social work. We examine some assumptions and arguments by the proponents of indigenization in social work and suggest that attempts at indigenization may be less beneficial in some countries than assumed.

French

Cet article survole le thème de l'autochtonisation dans le domaine des sciences sociales et du travail social. Les auteurs y examinent quelques hypothèses et quelques arguments des tenants de l'autochtonisation en travail social et ils en arrivent à la conclusion que les tentatives d'autochtonisation peuvent se révéler moins porteuses que prévu dans certains pays.

Spanish

Este artículo ofrece una breve revisión soble el discurso de indigenización en las ciencias sociales y en el trabajo social. Examinamos algunos supuestos y argumentos de los partidarios de la indigenización en el trabajo social y sugerimos que los intentos de indigenización, en algunos países, pueden ser menos beneficiosos de lo que se asume.
Domestic violence services in Romania
Authors: Wimmer Jane S. , Harrington Pamela Awtrey
Published: August 2008

English

A domestic violence program in Sighisoara, Romania was developed as a partnership between a US university and a Romanian NGO through USAID funding. Goals included capacity building and direct service. This successful program was evaluated using a longitudinal case study methodology from 2003 to 2007.

French

Un programme pour contrer la violence conjugale a été mis au point à Sighisora, en Roumanie, par une ONG locale, en collaboration avec une université américaine, et avec l'appui financier de USAID. Les objectifs visaient le renforcement des capacités et la prestation de services. Ce programme porteur a été évalué de 2003 à 2007 en appliquant la méthode d'analyse de cas longitudinale.

Spanish

En Sighisoara, Rumania, ha sido desarrollado un programa para la violencia doméstica en colaboración entre una universidad norteamericana y una ONG rumana, a través de la USAID. Las metas incluyeron la formación de capacidades y el servicio directo. Este exitoso programa fue evaluado mediante una metodología de estudio de caso longitudinal, de 2003 a 2007.
Transracial adoption
Authors: Heimsoth DeAnna , Laser Julie Anne
Published: August 2008

English

Qualitative research investigated expatriate families living in China with adopted Chinese children and the manner in which living in China influenced the adoptees' acquisition of their culture of origin. The values and cultural practices of these expatriate parents are also examined.

French

Il s'agit d'une recherche qualitative qui explore la situation des familles expatriées vivant en Chine et ayant adopté des enfants Chinois. Plus particulièrement, cette recherche examine la façon dont le fait de vivre en Chine a influencé les enfants adoptés à intégrer leur culture d'origine. Les valeurs et les pratiques culturelles des parents expatriés sont également examinées.

Spanish

Mediante investigación cualitativa se estudió a las familias expatriadas que viven en China con sus niños adoptivos chinos, y la forma en que vivir en China ha influenciado en éstos la adquisición de su cultura de origen. También son examinados los valores y prácticas culturales de estos padres expatriados.
Brazilian street children
Authors: Fernandes Giselle T. , Vaughn Michael G.
Published: August 2008

English

This article reviews the socioeconomic and political context of substance misuse by street children in Brazil. Although findings are limited, available research reveals an urgent need for implementation of policies for street children. Programs for preventing substance misuse and delinquency are still missing political and infrastructural support.

French

Cette étude analyse le contexte politique et socioéconomique qui entoure le mauvais emploi de substances par les enfants de la rue du Brésil. Bien que les résultats soient limités, la recherche indique que l'établissement de politiques concernant les enfants de la rue est un enjeu urgent. Il n'y a pas encore de cadre politique et d'infrastructures pour soutenir les programmes de prévention de la consommation et de la délinquance.

Spanish

Este artículo revisa el contexto socioeconómico y político del fundamento del abuso de niños de la calle en Brasil. Aunque los hallazgos son limitados, la investigación disponible revela una urgente necesidad de implementación de políticas respecto a los niños de la calle. Los programas para prevenir el fundamento del abuso y la delincuencia aún están ausentes de apoyo político e infraestructural.
Sub-Saharan Africa's orphan crisis
Authors: Lombe Margaret , Ochumbo Alex
Published: August 2008

English

The dramatic increase in the number of children made vulnerable by AIDS in sub-Saharan Africa has necessitated research in treatment and prevention. We contribute to the current discussion on the orphan crisis by proposing a multifaceted approach utilizing institutional characteristics, with greater potential to strengthen community capacity and empower vulnerable children.

French

L'accroissement phénoménal des enfants vulnérabilisés par le SIDA en Afrique sub-saharienne a eu pour effet de stimuler la recherche en matière de traitements et de prévention. Cette étude s'inscrit dans la réflexion courante sur la crise des orphelinats et propose une approche multidimensionnelle qui tire parti des caractéristiques institutionnelles tout en renforçant les capacités des communautés et en redonnant davantage du pouvoir aux enfants vulnérables.

Spanish

El dramático incremento en el número de niños que se han hecho vulnerables por el SIDA, en el África Subsahariana, ha hecho necesaria la investigación en tratamiento y prevención. Nosotros aportamos a la discusión actual sobre la crisis de huérfanos, proponiendo un acercamiento multifacético, utilizando las características institucionales con mayor potencial para fortalecer la capacidad comunitaria y empoderar a los niños vulnerables.
Letting Go Without a Fight: Decolonization, Democracy and War, 1900—94
Authors: Goldsmith Benjamin E. , Baogang He
Published: August 2008

Does the type of regime really make no difference to the likelihood of violent conflict over basic issues of stateness such as separatism and decolonization? Can democratic peace theory be successfully applied when dealing with the national identity or stateness question? This article extends the application of the democratic peace to the process of decolonization. It examines conflict between imperial states and their colonies during the process of decolonization and investigates the question of whether democracy affects the likelihood of conflict. The central finding is that, contrary to the implications of some prominent theories of state formation and democracy, democratic imperial states are significantly less likely to go to war with their colonial possessions in the process of achieving independence. Further, the authors find only a monadic, not dyadic, democratic peace effect. The regime type of the colony does not have a significant effect on the likelihood of war. It is the nature of the regime of imperial states, rather than that of colonies, that is a significant factor. In addition, the predominant source of this effect appears to be the institutional constraints placed on executive action within democracies, rather than the influence of mass politics or the effects of political competition. Regarding power-related factors, power parity between sovereign and colony makes conflict more likely (a colonial power-transition effect), but imperial decline actually makes war with colonies less likely. Sensitivity analysis reveals that a number of other hypothesized effects cannot find robust support. Simulations are used to assess the magnitude of the effect of regime type pre- and post-independence. Overall, the article contributes to theory development by investigating different institutional aspects of democracy and by distinguishing monadic and dyadic effects.
Taming the Leviathan: Examining the Impact of External Threat on State Capacity
Authors: Lektzian David , Prins Brandon C.
Published: August 2008

This article argues that the systemic security environment influences the structure of domestic political and economic institutions. If states have been primarily created to protect one group from predation by another, then the state may visibly change as external threats rise and fall. The authors argue that political elites respond to threatening environments by enhancing the ability of the state to extract resources from society in order to protect itself. Using data from the Armed Conflict Dataset, Banks's Cross National Data Archive, and COW data from 1975 to 1995, the authors find evidence that supports the conjectured relationship between threat and state strength. As a response to a more threatening environment, the authors find that states significantly increase their capacity in terms of revenue, government spending, and military spending, but they do not easily relinquish these gains. The authors also observe that nation-state security is heavily influenced by regional regime-type patterns. State capacity increases as the regional neighborhood becomes increasingly autocratic. This suggests political elites not only regard violent conflict in the region as a serious concern to national security, but also appear to consider political change a threat as well.
Bias in Epidemiological Studies of Conflict Mortality
Authors: Johnson Neil F. , Spagat Michael , Gourley Sean , Onnela Jukka-Pekka , Reinert Gesine
Published: August 2008

Cluster sampling has recently been used to estimate the mortality in various conflicts around the world. The Burnham et al. study on Iraq employs a new variant of this cluster sampling methodology. The stated methodology of Burnham et al. is to (1) select a random main street, (2) choose a random cross street to this main street, and (3) select a random household on the cross street to start the process. The authors show that this new variant of the cluster sampling methodology can introduce an unexpected, yet substantial, bias into the resulting estimates, as such streets are a natural habitat for patrols, convoys, police stations, road-blocks, cafes, and street-markets. This bias comes about because the residents of households on cross-streets to the main streets are more likely to be exposed to violence than those living further away. Here, the authors develop a mathematical model to gauge the size of the bias and use the existing evidence to propose values for the parameters that underlie the model. The research suggests that the Burnham et al. study of conflict mortality in Iraq may represent a substantial overestimate of mortality. Indeed, the recently published Iraq Family Health Survey covered virtually the same time period as the Burnham et al. study, used census-based sampling techniques, and produced a central estimate for violent deaths that was one fourth of the Burnham et al. estimate. The authors provide a sensitivity analysis to help readers to tune their own judgements on the extent of this bias by varying the parameter values. Future progress on this subject would benefit from the release of high-resolution data by the authors of the Burnham et al. study.
US Presidential War Powers: Legacy Chains in Military Intervention Decisionmaking
Authors: Paul Christopher
Published: August 2008

Using the events leading to the War Powers Resolution of 1973 and its subsequent impact on US military interventions as an empirical example, this article elaborates the notion of `legacy chains'. Expanding on the general notion of policy legacies, the discussion describes the effects that post-World War II US military interventions have had on each other through the policy legacies left by each in turn. The argument allows that military intervention legacies have their strongest impact on decisionmaking for an immediately subsequent intervention but can also leave durable impressions on the institutional context, which, after being modified by subsequent military interventions, constitute `legacy chains'. These legacy chains are path-dependent processes, in that their institutional embodiments follow `increasing returns' logics and will remain in place until the structure of returns changes, usually due to a `critical shift'. In response to a series of perceived abuses of presidential war powers following World War II, the War Powers Resolution sought to ensure congressional participation in future commitments of US forces to hostilities. It has not done so. The lasting legacy of the War Powers Resolution is an unintended consequence of the way it was formally institutionalized. Presidents, following the letter of the resolution, have designed post-War Powers Resolution military interventions to either be short (so the 60-day mandatory reporting period specified in the resolution ends with a fait accompli) or popular, so that public and congressional opinion are sufficient to ensure approval of the operation, either before it starts or once underway. While the actual legacy of the War Powers Resolution is not what was intended at its inception, it is unlikely to be formally changed until a future (hypothetical) abuse of war powers sufficiently egregious to break through its institutional inertia.
Adolescents' Explanations for Paramilitary Involvement
Authors: Muldoon Orla T. , Mclaughlin Katrina , Rougier Nathalie , Trew Karen
Published: August 2008

Current understanding of the motivations of young people who engage in paramilitary activity is poor. The youth bulge literature has made important advances in understanding determinants of political violence at population level; however, the psychological processes that underpin engagement with political violence among young people are less clearly understood. Further, the pathologization of terrorist activity has hampered deeper understanding of the motivations of those who seek to effect change using violence. This article explores the explanations offered by 14—16-year-olds regarding possible motivations of young people who engage in paramilitary activities in Ireland. Seventy-four Protestant and Catholic young people residing in the border regions of Northern Ireland and the Irish Republic completed an essay-writing task which elicited explanations for paramilitary involvement. Young people's explanations were multi-levelled and varied, reflecting the breadth and diversity of their personal circumstances and experiences. The essays were analysed using a Grounded Theory approach, which generated four categories of explanations for paramilitary involvement, namely, social identification explanations, family and socialization explanations, developmental explanations and pathological explanations. Though not asked to express a personal judgement regarding such activity, a substantial proportion of respondents did, with females being more likely than males to openly condone or condemn such activity. Discussion and interpretation of these findings centre on understanding of paramilitary involvement in areas affected by political violence.
Electrospun Nanoporous Fiber
Authors: Yue Wu  , Yu Jian-Yong , Chi Ma
Published: August 2008

Different concentrations of PBS/CF solution were prepared by dissolving Poly(butylenes succinate) (PBS) in Chioroform (CF) solvent. Single electrospun nanoporous fiber with an ultra-high specific surface was formed from electrospinning PBS/CF solution in a single processing step. As the concentration of PBS in CF increased, morphology evolved from beads only to ultra-fine continuous fibers. At a suitable concentration, PBS/CF 13%(w/w), uniform nanoporous threads of polymers were emitted from the jet by an electrospinning process. The electrospun nanoporous fibers were fabricated with average porous diameters of ~200 nm. The electrospun PBS fibers offer the potential for direct fabrication of biologically based, high-surface-area porous fibers without the use of multiple synthetic steps or post-processing surface treatments.
Numerical Analysis of Fiber Fleece Behavior in Roller Drafting in a Transient State
Authors: Kim Jong S. , Cherif Chokri , Huh You
Published: August 2008

Fiber bundle thickness irregularity from a roll draft mechanism was analyzed in the time domain on the basis of a theoretical model (Partial Differential Equation, PDE, system) for bundle flow. As the governing equations that consisted of continuity and motion equations turned out to be nonlinear, being coupled between variables, etc., a numerical method was established to solve the problem. In particular, the Forward-Time Central-Space (FTCS) difference formula with an explicit Euler scheme as the Finite Difference Method (FDM) was applied. Then the system of equations, which were in algebraic form, was solved according to given initial and boundary conditions in an iterative fashion. Results from this research confirmed that the theoretical response of the output linear density to the disturbance of drafting condition agreed very well with experiment. The transient state of the velocity profile faded out more quickly than that of the linear density profile. The response of the output bundle thickness to the step change perturbation depended on process conditions or material properties. With certain model parameters, the disturbed linear density of the output sliver converged to a fixed value or had an increasing variation magnitude. This indicated that the characteristics of the output bundle thickness could change according to the bundle properties or to the process conditions, which could induce unstable changes in thickness.
Understanding Residents' Attitudes toward the Development of Industrial Tourism in a Former Mining Community
Authors: Vargas-Sánchez Alfonso , Plaza-Mejía María de los Ángeles , Porras-Bueno Nuria
Published: August 2008

The topic of residents' attitudes toward tourism development has been analyzed by many authors, but there have been few studies that have included: (1) the impacts resulting from tourism perceived by residents of a particular region in a very early stage of tourism development, where, consequently, this industry is not yet economically important; (2) the relationship between the impacts of tourism perceived by residents and their degree of satisfaction with their community; and (3) a specific tourism segment, such as industrial tourism. The article presented here addresses these gaps in the literature, and focuses attention on the attitudes of the residents of Minas de Riotinto—a locality of the Spanish province of Huelva, traditionally involved in mining activity, which is now in decline and in the very initial phase of tourism development—toward greater development of tourism in their municipality, and on the factors that may determine and explain those attitudes.
Understanding the Relationship between Tourism Destination Imagery and Tourist Photography
Authors: Garrod Brian
Published: August 2008

Photography and tourism are widely considered to be intrinsically linked. Photographs play a crucial role in the promotion of tourism destinations, working through a range of media including brochures, television commercials, and picture postcards. Meanwhile the practice of photography is often held to be intimately related to the condition of being a tourist. Urry (1990) links these two phenomena, suggesting that they may constitute a self-reinforcing "closed circle of representation" in which tourist photographs both reflect and inform destination images. Using an innovative research approach combining visitor-employed photography with content analysis and quantitative statistical techniques, this article presents an empirical test of Urry's theory. Mixed evidence is found, suggesting that while in many respects the circle of representation may indeed be at work, in certain other respects it may not be. This suggests that a more fine-grained and nuanced understanding of the circle of representation is required.
A simple method for correcting time constant errors incurred in step scan systems
Authors: Fothergill I.R. , Neal W.E.J.
Published: August 2008

The spatial variation of parameters such as temperature or flow velocity in a region of interest is frequently measured using scanning techniques and the results displayed on a chart recording. In certain instances it may be necessary to perform the scans manually using a time step procedure in order to maintain synchronism with the recording equipment. The sensor is moved in small equal steps with a fixed time delay at each location before moving to the next. Unless the delay is very much longer than the system time constant, including the sensor response, then time constant errors may result in the recorded measurements.

This paper describes one of a number of techniques for correcting time constant errors incurred in these step scan systems. The method has the virtue of being simple to both understand and apply and sufficient background theory is included to convince the user that the approach is justified.
Improving the control of grinding processes using prediction from dynamic models
Authors: Cutting G.W. , Devenish M.
Published: August 2008

A method of developing a range of dynamic models of grinding processes is described, in which the structures of the models have been determined by a method which is best described as a regression upon the currently available expertise of the dynamic performance of grinding circuits. The models were developed initially on an analogue computer and subsequently the models have been transferred to a simulation language to provide greater flexibility. Grinding processes can present a large range of process control problems and the models have been designed for use as test beds during the design and development of mill control systems.
Digital algorithms for prediction, differentiation and integration
Authors: Forsythe W.
Published: August 2008

The subject is dealt with in three parts, covered in three consecutive papers as follows.

Part 1 presents a method of calculating the coefficients required in digital algorithms for prediction (including interpolation and extrapolation), differentiation and integration, both on and off line. It provides the means of computing rapidly, by hand or with the aid of a small calculator, the coefficients required for algorithms of any order up to eight.

Parts 2 and 3, to be published in subsequent issues, will consider the errors inherent in using the algorithms derived in Part 1 and draw significant conclusions about the interaction of quantisation level, sampling frequency, order of the algorithm and the effects of these quantities on the accuracy of the results. Part 2 will deal with prediction and integration algorithms; Part 3 with differentiation.
The application of an on-line model error tolerant sub-optimal controller to a chemical reactor
Authors: Litchfield R.J. , Locke A. , Campbell K.
Published: August 2008

The performance of multivariable non-linear stirred tank chemical reactor has been used to compare the practicability of an optimal controller and two types of suboptimal controller. The optimal controller, which by its nature required lengthy calculations, was suitable for open-loop control only and therefore sensitive to modelling errors. By contrast a suboptimal controller, which used the method of quasilinearisation to solve the two point boundary value problem, needed only a small amount of computation time and was capable of on-line implementation. This controller was much less sensitive to modelling errors, and also had the advantage of decoupling the control variables. An extension of this controller incorporated a feedback feature which compensated further for modelling errors and, in addition, unmeasured disturbances. This controller, which is expected to be of interest to the process industries facing inaccurate-model problems, produced responses close to the true optimal response even when the actual model used was in gross error.
An integrated steelworks energy model
Authors: Gathergood D.S. , Wild R.
Published: August 2008

This model enables the quantity of each form of energy used or produced within the steelworks to be calculated. A simple model of each of the main operating areas of the works has been devised enabling the quantities of each of the fuels used or produced in that area to be calculated for any given operating conditions. The total quantity of any form of energy utilised within the works can be found, for any given sequence of operating conditions, by summing the quantities produced or consumed in each unit operation and relating all quantities to the production of one tonne of liquid steel. The main emphasis in this study has been concentrated on the processes up to and including steel production.
Identification of ventilatory dynamics using pseudorandom binary sequences
Authors: Bennett Frederick M. , Reischl Peter , Grodins Fred S. , Yamashiro Stanley , Fordyce Wayne E.
Published: August 2008

A controversy exists concerning how best to describe the dynamics of the ventilatory response to exercise in man. The results of studies which used step, ramp and sinusoidal forcings of work have implied that there is a single slow, presumably humoral, component. However, application of short duration pulses of very heavy work gave results consistent with a rapid, presumably neural, component in addition to the slower dynamics. There are two factors which may be responsible for the conflict: (1) differences in the frequency content of the input signals and (2) the large work loads used in the pulse study may have induced an artifact. In the present study five subjects exercised on a bicycle ergometer while the work load was varied as a pseudorandom binary sequence (PRBS). The first order Wiener kernels were calculated by cross-correlation techniques. All subjects clearly demonstrated a rapid component. When the frequency content of the PRBS was lowered such that it excited a range similar to the sinusoidal studies, a rapid component was not evident in the cross- correlation. This suggests that previous studies failed to identify a rapid component because of the low range of frequencies over which the respiratory system was stimulated, Work loads used in this study were of moderate intensity. Evidence is presented which verifies that the PRBS technique is a valid method of testing the respiratory system. The advantages of using this technique are also discussed.
A practical means of quantitatively describing the topographies of machined surfaces
Authors: Edmonds M.J. , Snaith B. , Probert S.D.
Published: August 2008

The design of an automated system for assessing surface texture is described. In this, a parallel profile tracing tech nique has been developed which can provide detailed analyses of surfaces of up to 2500 mm 2 in area. Microprocessor controlled data handling, with a storage capability of 5 x 105 height readings and ensemble averaging of up to 100 successive retraces, is employed. Typical statistically computed outputs, together with surface isometric and contour plots, are presented for surfaces with different machine finishes.