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Wide Gap (wide + gap)

Distribution by Scientific Domains

Medical Sciences	33%

Selected Abstracts

Rural tourism and the development of less favoured areas,between rhetoric and practice,

INTERNATIONAL JOURNAL OF TOURISM RESEARCH, Issue 3 2002
Manuela Ribeiro
Abstract Tourism has, in recent times, been advocated as a particularly efficient way to promote the development of the so-called less favoured regions, mostly inland and mountain, owing to its potential for employment and income creation and the synergies it is able to generate in other sectors of activity. Based on the results of empirical research carried out in two distinct inland zones of Portugal, this article tries to demonstrate that a wide gap and considerable contradictions are emerging between the rhetoric and the real benefits that tourism has been producing in the local societies and economies of these regions. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Characterization of Taylor vortex flow in a short liquid column

AICHE JOURNAL, Issue 12 2009
Rensheng Deng
Abstract We present a study on Taylor vortex flow in the annulus between a rotating inner cylinder and a stationary outer cylinder, featured with a wide gap (radius ratio is 0.613) and a short column (aspect ratio is 5.17). A particle image velocimetry (PIV) system was used to determine the position, shape, and velocity distribution of the vortices, by which the flow was also confirmed to lie in the nonwavy Taylor vortex regime for all operating conditions explored in this study. Our results suggest that end boundary effects are important, in which the vortex number decreases with decreasing column length. For a system with an aspect ratio of 5.17, six vortices appear in the gap with their position, size, and shape varying at different Reynolds numbers. The fluid velocities show an asymmetric feature with respect to the vortex centers, while the maximum axial and radial velocities increase almost linearly with the increasing reduced Reynolds number (Re , Rec). In addition, computational fluid dynamics study was employed under the same conditions, and its results agree well with the PIV measurements. Overall, this study provides a quantitative understanding of the formation of Taylor vortices in a constrained space. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

Americans' Views of Health Care Costs, Access, and Quality

THE MILBANK QUARTERLY, Issue 4 2006
ROBERT J. BLENDON
For more than two decades, polls have shown that Americans are dissatisfied with their current health care system. However, the public's views on how to change the current system are more conflicted than often suggested by individual poll results. At the same time, Americans are both dissatisfied with the current health care system and relatively satisfied with their own health care arrangements. As a result of the conflict between these views and the public's distrust of government, there often is a wide gap between the public's support for a set of principles concerning what needs to be done about the overall problems facing the nation's health care system and their support for specific policies designed to achieve those goals. [source]

Tissue response to titanium implantation in the rat maxilla, with special reference to the effects of surface conditions on bone formation

CLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2003
Masaki Shirakura
Abstract: Tissue responses to titanium implantation with two different surface conditions in our established implantation model in rat maxillae were investigated by light and transmission electron microscopy and by histochemistry for tartrate-resistant acid phosphatase (TRAPase) activity. Here we used two types of implants with different surface qualities: titanium implants sandblasted with Al2O3 (SA-group) and implants coated with hydroxyapatite (HA-group). In both groups, bone formation had begun by 5 days postimplantation when the inflammatory reaction had almost disappeared in the prepared bone cavity. In the SA-group, however, the bone formation process in the bone cavity was almost identical to that shown in our previous report using smooth surfaced implants (Futami et al. 2000): new bone formation, which occurred from the pre-existing bone toward the implant, was preceded by active bone resorption in the lateral area with a narrow gap, but not so in the base area with a wide gap. In the HA-group, direct bone formation from the implant toward the pre-existing bone was recognizable in both lateral and base areas. Many TRAPase-reactive cells were found near the implant surface. On the pre-existing bone, new bone formation occurred with bone resorption by typical osteoclasts. Osseointegration around the implants was achieved by postoperative day 28 in both SA- and HA-groups except for the lateral area, where the implant had been installed close to the cavity margin. These findings indicate that ossification around the titanium implants progresses in different patterns, probably dependent on surface properties and quality. Résumé Les réponses tissulaires à l'implantation du titane avec deux conditions de surfaces différentes dans le maxillaire du rat ont étéétudiées par microscopie optique et électronique à transmission et par histochimie pour l'activité de l'acide phosphatase résistant au tartrate (TRAPase). Deux types d'implants avec différentes qualité de surface ont été utilisés : des implants en titane sablés par du AL2O3 (groupe SA) et des implants couverts par de l'hydroxyapatite (groupe HA). Dans les deux groupes la formation osseuse avait démarré cinq jours après l'implantation, lorsque la réaction inflammatoire avait presque disparue de la cavité osseuse préparée. Cependant, dans le groupe SA le processus de formation osseuse de la cavité osseuse était quasi identique à celle montrée dans un rapport précédent utilisant des implants à surface lisse (Futami et al., 2000) : la néoformation osseuse qui démarre de l'os préexistant vers l'implant, était précédée par une résorption osseuse active dans l'aire latérale avec une brèche étroite, mais pas dans l'aire de base avec un espace large. Dans le groupe HA, une formation osseuse directe de l'implant vers l'os préexistant était reconnaissable tant dans les aires latérales qu'au niveau de la base. Beaucoup de cellules réactives au TRAPase ont été trouvées près de la surface de l'implant. Sur l'os préexistant une néoformation osseuse est apparue avec une résorption osseuse par des ostéoclastes typiques. L'ostéoïntégration autour des implants a été achevée au jour 28 après l'opération tant dans le groupe SA que HA excepté pour l'aire latérale où l'implant avait été inséré près du rebord de la cavité. Ces découvertes indiquent que l'ossification autour des implants en titane progresse de manière différente dépendant probablement de la qualité et des propriétés de surface. Zusammenfassung Die Gewebsantwort auf implantiertes Titan in einem Rattenoberkiefer. Spezielles Augenmerk auf die Einflüsse der Oberflächenbeschaffenheit auf die Knochenbildung. An unserem etablierten Implantationsmodell am Rattenoberkiefer wurde die Gewebsantwort nach der Titanimplantation von zwei Prüfkörpern mit verschiedener Oberfläche mit Hilfe der Licht- und Transmissionselektronenmikroskopie, sowie mittels Histochemie zum Aktivitätsnachweis der tartratresitenten sauren Phosphatase (TRAPase) untersucht. Wir benutzten hier zwei Implantattypen mit verschiedenen Oberflächen: Mit Al2O3 sandgestrahlte Titanimplantate (SA-Gruppe) und mit Hydroxylapatit beschichtete Implantate (HA-Gruppe). Bei beiden Gruppen begann die Knochenbildung 5 Tage nach der Implantation, sobald die Entzündungsreaktion im präparierten Knochenbett am verschwinden war. In der SA-Gruppe aber, zeigte sich im präparierten Implantatbett ein beinahe gleicher Knochenbildungsvorgang, wie in unseren früheren Berichten für glatte Implantatoberflächen beschrieben (Futami et al., 2000): Die vom bereits vorhandenen Knochen ausgehende Knochenneubildung gegen das Implantat hin erfolgte erst nach einer aktiven Knochenresorption im lateralen Bereich. Es entstand eine minime Spalte zwischen Knochen und Implantat, währenddem im apicalen Bereich eine breitere Spalte entstand. In der HA-Gruppe konnte man sowohl im lateralen, wie auch im apicalen Bereich eine direkt vom Implantat ausgehende Knochenbildung in Richtung des vorhandenen Knochens feststellen. In der Nähe der Implantatoberfläche fand man viele TRAPase-reaktive Zellen. Beim vorhandenen Knochen erfolgte die Knochenneubildung gleichzeitig mit der Knochenresorption durch typische Osteoklasten. Die Osseointegration rund um die Implantate herum erreichte man, ausser im lateralen Bereich gegen den Rand des Implantatbettes hin, in der SA-und der HA-Gruppe am 28igsten postoperativen Tag. Diese Ergebnisse zeigen, dass die Ossifikation um Titanimplantate in verschiedenen Mustern abläuft, wahrscheindlich in Abhängigkeit von der Oberflächeneigenschaft und -qualität. Resumen Se investigó las respuestas tisulares a la implantación con titanio con dos condiciones diferentes de superficie en nuestro modelo establecido de implantación en el maxilar de la rata por medio de microscopía óptica y electrónica de transmisión y por medio de histoquímica para la actividad de fosfatasa alcalina tartrato resistente (TRAPase). Hemos usado aquí dos tipos de implantes con diferentes calidades de superficies: Implantes de titanio pulverizados con Al2O3 (grupo-SA), e implantes cubiertos con hidroxiapatita (grupo-HA). En ambos grupos la formación de hueso comenzó a los 5 días de la implantación cuando la reacción inflamatoria hubo casi desaparecido en la cavidad ósea preparada. De todos modos, en el grupo SA, el proceso de formación de hueso en la cavidad ósea fue casi idéntico a aquel mostrado en nuestro informe previo usando implantes de superficies lisas (Futami et al., 2000): neoformación de hueso, que tuvo lugar desde el hueso preexistente hacia el implante, siendo precedida por reabsorción ósea activa en el área lateral con un espacio estrecho, pero no así en el área basal con espacio ancho. Se encontraron muchas células TRAPase reactivas cerca de la superficie del implante. En el hueso preexistente, la neoformación ósea tuvo lugar con reabsorción ósea con osteoclastos típicos. La osteointegración alrededor de los implantes se logró al día 28 tras la operación en ambos grupos SA y HA excepto para el área lateral, donde el implante se instaló cerca del margen de la cavidad. Estos hallazgos indican que la osificación alrededor de los implantes de titanio progresa con patrones diferentes, probablemente dependiendo de las propiedades y las calidades de la superficie. [source]

Universal ideals and particular constraints of social citizenship: the Chinese experience of unifying rights and responsibilities

INTERNATIONAL JOURNAL OF SOCIAL WELFARE, Issue 2 2004
Chack Kie Wong
This study looks at the perceptions of citizens in a modern Chinese society and explores whether social rights and responsibilities are unified at both ideal and practice levels. It finds that the conception that the Chinese have a weak image of social rights is no longer true. The Chinese are generally ,right-deficit' at the practice level. It is also found that there are wide gaps between ideal rights and practice rights, and between ideal responsibilities and practice responsibilities, except in components affected by cultural, contextual and institutional factors. The findings suggest that, for a full understanding of social citizenship, it is necessary to look at both ideal and practice levels of social citizenship. Cultural, contextual and institutional factors are identified as moderating people's behaviour and preferences in regard to social citizenship. [source]

Acclimation of tropical tree seedlings to excessive light in simulated tree-fall gaps

PLANT CELL & ENVIRONMENT, Issue 12 2001
G. H. Krause
Abstract Acclimation to periodic high-light stress was studied in tree seedlings from a neotropical forest. Seedlings of several pioneer and late-succession species were cultivated under simulated tree-fall gap conditions; they were placed under frames covered with shade cloth with apertures of different widths that permitted defined periods of daily leaf exposure to direct sunlight. During direct sun exposure, all plants exhibited a marked reversible decline in potential photosystem II (PSII) efficiency, determined by means of the ratio of variable to maximum Chl a fluorescence (Fv/Fm). The decline in Fv/Fm under full sunlight was much stronger in late-succession than in pioneer species. For each gap size, all species exhibited a similar degree of de-epoxidation of violaxanthin in direct sunlight and similar pool sizes of xanthophyll cycle pigments. Pool sizes increased with increasing gap size. Pioneer plants possessed high levels of , -carotene that also increased with gap size, whereas , -carotene decreased. In contrast to late-succession plants, pioneer plants were capable of adjusting their Chl a/b ratio to a high value in wide gaps. The content of extractable UV-B-absorbing compounds was highest in the plants acclimated to large gaps and did not depend on the successional status of the plants. The results demonstrate a better performance of pioneer species under high-light conditions as compared with late-succession plants, manifested by reduced photoinhibition of PSII in pioneer species. This was not related to increased pool size and turnover of xanthophyll cycle pigments, nor to higher contents of UV-B-absorbing substances. High , -carotene levels and increased Chl a/b ratios, i.e. reduced size of the Chl a and b binding antennae, may contribute to photoprotection in pioneer species. [source]