bluuebunny/crossref_metadata_2025 huggingface dataset:
Pliocene and Quaternary surface uplift evidenced by sediments of the Loire Allier river system (France) [ Mise en évidence du soulèvement des surfaces continentales au Quaternaire et au Pliocène d'après les sédiments du système Loire-Allier (France).]
Authors: Westaway Rob
Published: October 2009

Des systèmes de terrasses couvrant une longue période de temps sont largement observés dans le centre de la France le long de la Loire et de l'Allier. Ils sont aussi présents au nord dans le bassin de la Seine, bassin débouchant dans la Manche, auquel la Loire était raccordée avant son changement de cours en direction de l'Atlantique. De nombreux aspects de l'enregistrement fluviatile plio-quaternaire de ce système peuvent être expliqués par la modélisation rheologique, comme réésultant de mouvements crustaux verticaux causes par le couplage entre les processus de surface et le flux subordonné de la base de la croûte. En comparaison avec d'autres régions d'Europe ayant fait l'objet de travaux comparables, cette région est plus complexe car les rhéologies de la croûte varient latéralement en fonction de la décroissance du flux de chaleur vers l'extérieur à partir du Massif Central. Les charges de surface et les allégements causés par l'érosion varient aussi latéralement en fonction de la distribution du volcanisme centralien. L'histoire de l'ajustement du cours inférieur de la Loire entre la Manche et l'Océan Atlantique peut être expliquée comme une conséquence des modifications nord-sud du soulèvement dans le temps, modifications causées par les variations latérales dans le flux de chaleur. II n'est pas nécessaire de faire appel à des processus indépendants, comme la présence d'un panache mantellique sous le Massif Central pour expliquer le soulèvement observé
Evolution of the fluvial system of the Prypiat, Desna and Dnieper during the Late Middle - Late Pleistocene [ Evolution des systèmes fluviatiles des rivières Prypiat, Desna et Dniepr au cours du Pléistocène moyen récent et du Pléistocène supérieur. ]
Authors: Matoshko Andreï V.
Published: October 2009

A hypothesis that envisages Late Pleistocene braided rivers with enlarged meanders, unlike the present rivers of the European plains, anses from a tentative model for the development of the Prypiat-Dnieper-Desna alluvial plain in the late Middle - Late Pleistocene. This plain (local relief - 30-60 m) consists of a staircase of six river terraces and corresponding alluvial suites that have been forming since the Dnieper (Saale) Glaciation. Each terrace occupies a definite altitudinal step in this staircase and has a unique position within the plain as well as characteristic relief features related to terrace boundary shapes, longitudinal and cross profiles, primary fluvial and superimposed aeohan, cryogenic and erosional landforms. The alluvial suites have a cut-and-fill framework and noticeable differences in faciès composition expressed by sedimentary structures and other hthological features. Data inferred from the relief and from geological structures indicate complex fluvial system development with six main stages of varying duration and significance. These comprised one accumulative phase and five erosion-accumulation cycles, associated with weak pulsating tectonic uplift, expressed as 7-20 m of incision. The direct influence of the decay of the Dnieper ice sheet, alternations of glacial -interglacial runoff and stream load, significant fluctuations of precipitation, displacement of vegetation zones as well as permafrost thaw, all caused changes in the fluvial erosion-sedimentation regime. Glacially-fed suspended load streams, sandy meandering and braided streams, as well as sandy bedload braided and low sinuosity streams succeeded each other following the Dnieper Glaciation. These changes were accompanied by remarkable transformations of the river network general westward displacement, downstream displacement during the latest stages, abandonment of tributaries and inner fan formation. Proof of the existence of discontinuous permafrost or deep seasonal frost penetration has been obtained for the first time in the Late Pleistocene fluvial deposits of the area. Relying on the evidence of cryogenic and aeohan activity, the final phases of accumulation of the 1st Terrace Suite presumably correlate with the maximum of the Last Glaciation and the formation of the Peripheral Terrace Suite with permafrost degradation at the end of the Late Pleistocene.
The suitability of dated travertines as a record of fluvial incision: Allier (France) floodplain dynamics during the Late quaternary [ Validité des travertins datés pour la reconstitution de l'histoire de l'incision fluviatile. La dynamique de la nappe alluviale de l'Allier pendant le Quaternaire récent.]
Authors: Veldkamp Antonie , Kroonenberg Salomon , Heijnis Henk , Van Den Berg Van Saparoea Rob
Published: October 2009

Travertines overlying and impregnating Allier terraces have been dated and confirm previous research that they register past spring activity for the last 250 kyr New U-senes ages demonstrate that surface travertines were not only mainly deposited under Interglacial but also under Interstadial conditions Detailed reconstruction of the Holocene fluvial incision suggests that the position of surface travertine precipitation at terrace scarps bear a relationship with floodplain incision (terrace formation) Unfortunately the temporal resolution of current U-senes dates is too coarse to allow a detailed reconstruction for older cycles. Travertine dating with 14C has proved to be unreliable as a result of the contamination with fossil carbonates
Example of Holocene alpine torrent response to environmental change: contribution to assessment of forcing factors [ Un exemple de réponse d'un torrent alpin aux changements environnementaux à l'Holocène contribution à l'analyse des facteurs de forçage]
Authors: Flez Christophe , Lahousse Philippe
Published: October 2009

Si les grandes lignes de l'évolution de la torrentialité Holocène des Alpes du Sud sont désormais connues, on sait que les caractéristiques intrinsèques de chaque bassin versant et les modalités de leur anthropisation influent sur la réponse géomorphologique fournie aux changements environnementaux. Situé dans la moyenne vallée de l'Ubaye, l'Abéous est à notre connaissance le seul torrent des Alpes françaises à avoir livré suffisamment d'informations pour que l'on puisse en reconstituer l'histoire tout au long de l'Holocène. Les auteurs mettent en évidence le caractère récurrent des faciès torrentiels dans la stratigraphie du cône de déjection de ce torrent, y compris à l'Atlantique et constatent une accentuation du caractère torrentiel depuis l'Age du Bronze. Ils s'interrogent par ailleurs sur les conditions de formations des épais niveaux limoneux qui composent pour partie le «remplissage holocène principal». A la lumière de cette longue évolution, l'article propose une analyse de la dynamique contemporaine de reboisement spontané et de rétraction de la bande active du torrent
Hydrogeomorphic effects of beaver dams on floodplain morphology: avulsion processes and sediment fluxes in upland valley floors (Spessart, Germany) [ Les effets hydro-géomorphologiques des barrages de castors sur la morphologie de la plaine alluviale : processus d'avulsions et flux sédimentaires des vallées intra-montagnardes (Spessart, Allemagne).]
Authors: John Stefan , Klein Andreas
Published: October 2009

In a two years study, several methods were used to visualise and analyse beaver-induced hydrogeomorphic changes of channel pattern, sediment fluxes and erosion processes on the upland valley floor of the 3rd order river Jossa (Spessart/Germany). There, the re-introduced population of Castor fiber albicus shows intensive dam-building activity Using GIS and aenal photography, different stages of river and floodplain morphology (1998-2001) were mapped In addition, length of water courses, areal extent of ponds and wetlands, sediment depths, volumes and sedimentation rates, as well as erosion rates and amounts of eroded matenal were calculated. The results revealed that beaver dams create large wetlands and greatly increase the area of open water surface and quiet reaches by damming-up ponds. Moreover, they enhance the total water flow length by diverting water onto the floodplain, resulting in a multi-channeled (anastomosing) drainage network Where pond drainage was concentrated on a few relative stable channels, headcut erosion led to the development of one single dominant channel. Five stages of this development to a channel relocation were observed, resembling stages of a gradual avulsion. This implies that beaver dams should be recognised as possible - or even as important - avulsion triggers Intensified deposition of predominantly sands and organic silts occurred within the beaver ponds. Moreover, extended avulsion deposits caused by permanent overbank flow revealed the multi-channeled drainage network to be an important depositional environment of beaver sites. The highest amounts of sediments were deposited within the channel-bed and adjacent anthropogenic ditches, smaller amounts were accumulated on the inundated floodplain. The results may provide a rationale for attributing beaver activities a high significance as a forcing factor of Quaternary floodplain development along low order rivers in Central Europe.
Formations sédimentaires et évolution de la vallée de la Deûle depuis le Pléniglaciaire supérieur à Houplin-Ancoisne (Nord de la France)
Authors: Deschodt Laurent , Salvador Pierre Gil , Boulen Muriel
Published: October 2009

Dans la région d'Houplin-Ancoisne (vallée de la Deûle, Nord), l'ampleur de la sédimentation loessique du Pléistocène supérieur dans le fond de vallée a favorisé la conservation des dépôts fluviatiles antérieurs, sur une bande de plus de 3 km de large et parfois jusqu'à 22 m d'épaisseur. Un transect partiel de la vallée de la Deûle a révélé un chenal tardiglaciaire qui incise sur environ 3 m les dépôts antérieurs, créant une terrasse Plésitocène supérieur / Tardiglaciaire. Son remblaiement débute précocement au Bolling, mais la majeure partie du comblement est datée du Dryas récent après un dépôt lité relativement riche en débris végétaux (environ 1 m), la partie supérieure (0,9 m) est azoïque et s'accumule rapidement (après 12350-12150 cal BP). Ce comblement terminal du Dryas recent témoigne d'une relative sécheresse et d'une modification de la morphologie du chenal. L' incision holocène, décalée par rapport au chenal tardiglaciaire, est plus modérée. Elle dégage une morphologie de basses terrasses creusées dans les nappes fluviatiles antérieures et le loess qui les scelle. Après un dépôt grossier, la tourbe se développe a partir du Boréal, déborde du lit mineur et ennoie les zones les plus basses du fond de vallée. La palynozone atlantique repérée dans la tourbe offre l'image d'un paysage boisé dominé par le Tilleul avec des traces d'anthropisation fugaces. Depuis le Néolithique, la micro-topographie du bas de versant à proximité de la rive droite est peu à peu régularisée par les colluvions.
Price Dispersion: An Empirical Analysis in the Tour Operating Industry
Authors: Alegre Joaquín , Sard Maria
Published: October 2009

Price dispersion refers to the existence of a nondegenerated distribution of prices by the sellers of a product or service with similar features. Price dispersion is a clear reality in the tour operating market, although very little attention has been given to an analysis of
this kind of dispersion and price oscillations in package holidays. In this article, the existence of inter- and intrafirm price dispersion and its persistence over time are analyzed. For the purpose of the analysis, a dataset of package holiday prices for the Balearic Islands is used from
a sample of British and German tour operators. The results show the existence of persistent differences in the mean prices of tour operators and price distributions with different dispersions and shapes for tour operators and markets. Nevertheless these distributions are not static, showing
a swift response to market demands. Although the article is presented as an empirical investigation, the results can be interpreted in the context of theoretical literature on price dispersion.
The Economic Impact of Hawaii's Cruise Industry
Authors: Pratt Stephen , Blake Adam
Published: October 2009

The cruise industry worldwide has increased rapidly since the beginning of the millennium. Hawaii is no exception to this. Since the 1970s, cruise ships periodically visited the Hawaiian Islands, yet overnight cruising among the islands was rare. From 2001 to 2004, cruise ships sailing
to and around Hawaii were solely foreign-flagged ships, including those home based in Hawaii. This meant much of the tourism revenue and taxes did not accrue to the local economy. Since July 2004, in addition to the foreign-flagged ships, a U.S.-flagged ship has been home-ported in the islands,
paying Hawaii taxes and hiring U.S. crews with two more U.S.-flagged ships being added to the fleet in 2005 and 2006. This article uses a computable general equilibrium (CGE) model to estimate the economywide economic impact of the cruise industry on the state of Hawaii. Using the 2002 intercounty
input–output table as a benchmark, the multiregion CGE model takes the direct expenditure estimates of cruise passengers, expenditure by cruise crews, and the direct expenditures by the cruise lines, as computed by the State of Hawaii and uses these direct impacts as simulations in the
CGE model. Gross value added and welfare are calculated for each county and the state as a whole. Some regions benefit more than others.
International Tourism in the Coastal Regions of Five Mediterranean Countries
Authors: Quintiliani Fabio
Published: October 2009

This article aims to highlight both some of the determinants of foreign tourist demand and the main structural features of coastal regions in Italy, Spain, Greece, Croatia, and Cyprus over the period 1999–2004. The analysis is carried out on the basis of an original three-dimensional
panel dataset featuring a wide range of variables collected from a large set of sources. Weighted price competitiveness indicators are also calculated with weights built so as to contemporaneously account for the relative importance, for each region of destination, of both its foreign tourist
markets and of its rival regions. Descriptive analysis shows that foreign tourists' hotel arrivals and night stays increased in Adriatic Croatia, entailing a rise in its market shares. In other regions, tourist flows either stagnated or declined, owing to the decrease in the number of travelers
from Germany, one of the two main tourist markets for the Mediterranean countries. Italy's coastal regions performed below their potential, succeeding in attracting tourists mainly for the local art and historic heritage sites rather than for their "sea-and-sun" attractions. They could only
partially reap the benefits of increased air passenger traffic, and their market shares did not increase despite price competiveness gains. Panel data regressions with fixed nationality, regional, and time effects show that international tourist flows to coastal regions are negatively correlated
with price indicators and with the distance between coastal regions and tourists' homelands. Tourist movements are instead positively correlated with the country of origin's per capita GDP, the presence of renowned heritage or natural sites, and the international air passenger traffic at local
airports. Policy interventions that foster structural improvements, such as the accessibility by air from abroad, may improve the qualitative competitiveness of the coastal regions.
Estimating the Economic Benefits from Outdoor Recreation on a Scenic Route: The Ponale Road
Authors: Notaro Sandra , de Salvo Maria
Published: October 2009

The Ponale Road features a spectacular panorama, consisting of one of the most beautiful mountain-top views of Lake Garda (northern Italy). In the past, it attracted large numbers of tourists from all over Europe, especially mountain bikers, due to its unique characteristics. However,
it was closed at the end of the 1990s due to geological instability. In this study, we estimated the social benefit of the reopening of this scenic route using the contingent valuation method, focusing exclusively on its recreational use value. During 2002, we conducted face-to-face interviews
with 675 randomly drawn potential users of the road and got a response rate of 96%. Our target population was all potential road users, both tourists and residents, because at the time the research was carried out the road was closed to any type of use. A hypothetical scenario proposed the
reopening of the road conditional on users paying an access fee. We elicited willingness to pay (WTP) using a payment-card format. The Cameron and Huppert parametric interval regression method was used to analyze data. Benefits compared with annual cost of maintenance show the attractiveness
of the project. The feasibility of a pricing policy was also evaluated.
Labor Conditions in the Spanish Hotels and Restaurants Industry
Authors: Fernández Melchor , Pena-Boquete Yolanda , Pereira Xesús
Published: October 2009

The tourism and hotels and restaurants industries fall within the service sector and employ many people with different skills and capacities. As in other sectors, it is important to monitor employment and working conditions in this sector. However, there has not been any empirical systematic
research into employment and wage conditions in the Spanish hotels and restaurants sector, partly because of the complexity and size of the sector. All studies that exist on salary levels in the tourism industry emphasize the fact that the hotels and restaurants sector is among the lowest
paid business sectors and it employs a large proportion of women and nonqualified labor. Such characteristics generate lower pay and greater risk of gender discrimination. The aim of this article is to analyze these two negative aspects of labor market conditions in the hotels and restaurants
industry in Spain and to discuss regional differences comparing tourism regions and nontourism regions. We show that low-wage incidence in the hotels and restaurants industry disappears with the tourism development of the sector, that is, it is lower in the tourism regions. Nevertheless, gender
discrimination does not depend on the tourism or nontourism characterization of regions.
A Framework to Analyze Productivity Changes: Theoretical Aspects and Application to the Portuguese Travel Agencies Sector
Authors: Barros Carlos Pestana , Botti Laurent , Peypoch Nicolas
Published: October 2009

This article proposes a new framework for analyzing decision-making unit (DMU) productivity changes during two time periods. This method is based on the Luenberger productivity indicator, which uses the directional distance function. The method has two advantages, which are explained in the article. First, it evaluates simultaneously the scale of the economies and the improvements in production that have been achieved by each observed entity during the time span. Thus, it can be considered as a method that indicates the performance evolution of DMUs. Moreover, it indicates technical efficiency and technological changes during the period. This framework is applied to a Portuguese travel agencies sample that has faced a number of threats during the period 2000–2004. Conclusions are that productivity increased for the majority of the travel agencies analyzed and that these good performances are almost always explained by technical progress. Some managerial implications beneficial for agencies' productivity are drawn from this study.
On Linear Independence of a Certain Multivariate Infinite Product
Authors: Choi Stephen , Zhou Ping
Published: October 2009

Letq,m,M≥ 2 be positive integers andr1,r2, … ,rmbe positive rationals and consider the followingMmultivariate infinite products

fori= 0, 1, … ,M–1. In this article, we study the linear independence of these infinite products. In particular, we obtain a lower bound for the dimension of the vector space ℚF0+ℚF1+· · ·+ℚFM–1+ℚ over ℚ and show that among theseMinfinite products,F0,F1, … ,FM–1, at least ∼M/m(m+ 1) of them are irrational for fixedmandM→ ∞.
The Numerical Range of 2-Dimensional Krein Space Operators
Authors: Nakazato Hiroshi , Bebiano Natália , da Providência João
Published: October 2009

The tracial numerical range of operators on a 2-dimensional Krein space is investigated. Results in the vein of those obtained in the context of Hilbert spaces are obtained.
Dynamical Zeta Function for Several Strictly Convex Obstacles
Authors: Petkov Vesselin
Published: October 2009

The behavior of the dynamical zeta function ZD(s) related to several strictly convex disjoint obstacles is similar to that of the inverse Q(s) = of the Riemann zeta function ζ(s). Let Π(s) be the series obtained from ZD(s) summing only over primitive periodic rays. In this paper we examine the analytic singularities of ZD(s) and Π(s) close to the line , where s2 is the abscissa of absolute convergence of the series obtained by the second iterations of the primitive periodic rays. We show that at least one of the functions ZD(s), Π(s) has a singularity at s = s2.
First Variations of the Best Sobolev Trace Constant with Respect to the Domain
Authors: Rossi Julio D.
Published: October 2009

In this paper we study the best constant of the Sobolev trace embedding H1(Ω) → L2(∂Ω), where Ω is a bounded smooth domain in ℝN. We find a formula for the first variation of the best constant with respect to the domain. As a consequence, we prove that the ball is a critical domain when we consider deformations that preserve volume.
Stepping-Stone Model with Circular Brownian Migration
Authors: Zhou Xiaowen
Published: October 2009

In this paper we consider the stepping-stone model on a circle with circular Brownian migration. We first point out a connection between Arratia flow on the circle and the marginal distribution of this model. We then give a new representation for the stepping-stone model using Arratia flow and circular coalescing Brownian motion. Such a representation enables us to carry out some explicit computations. In particular, we find the distribution for the first time when there is only one type left across the circle.
An Exploratory Study on the Critical Success Factors in the Implementation of Enterprise Resource Planning Systems in Venezuela
Authors: Colmenares Leopoldo
Published: October 2009

This paper reports on an exploratory study, carried out in seven Venezuelan organizations who have successfully implemented an enterprise resource planning (ERP) system. The data were collected by means of both a questionnaire and of conducted interviews to the seven project managers of the project of implementation of ERP systems in these enterprises. The purpose of the study was to know the perceptions the project managers, on aspects and activities of the process of implementing an ERP system and that are strongly correlated with the Critical Success Factors (FCE’s) for this kind of projects. The FCE’s were identified in a deep revision of the literature. The questionnaire included, among others, questions on the top management support to the project, the process of selection of the system, team work implementation and the participation and training of the users. Additionally were identified the problems that organizations confronted during the implementation process. The study concludes that organizations must take care the elements that indicate the FCE’s, because them hit positively the project, additionally describe aspects, which must take into account the enterprises who are in the process to adopt an ERP system to facilitate its implementation.
Information Systems: New Ontologies-Based Scenarios
Authors: Elisa Barchini Graciela , María Álvarez Margarita , Herrea Susana
Published: October 2009

While ontology is still a fertile area of research in the field of Philosophy, Ontologies currently stands for research, development, and application fields in disciplines related with computing, information and knowledge. Information Systems (IS) are essentially knowledge artifacts that capture and represent knowledge in certain domains. Considering that ontologies is generally used to specify and communicate knowledge in a domain, and the growing recognition that ontological principles and concepts can be fruitfully applied to the IS field, one could say that an IS has its own implicit ontology when attributing meaning to the symbols used. Explicitly, however, ontology may play different roles in an IS. The scenarios presented in this article allow visualizing the roles that ontologies are now playing or will play in the near future in IS. There is a wide range of uses for ontologies in the different scenarios - they vary from the conceptual analysis of IS modeling techniques to their use as support for IS design, development and application. Our knowledge on the roles played by ontologies in IS is expected to be expanded.
Evaluating the Service Quality of Thirdparty Logistics Service Providers Using the Analytic Hierarchy Process
Authors: So Soon-hoo , Kim JaeJon , Cheong KiJu , Cho Geon
Published: October 2009

In this study we apply the analytic hierarchy process (AHP) to evaluate the service quality of third-party logistics (3PL) service providers. We first conceptualize five dimensions of 3PL service quality (i.e. tangibles, reliability, responsiveness, assurance and empathy). We then apply the AHP method to determine the relative weights of the five service quality dimensions and eventually select the best 3PL service provider. To implement this idea in practice, we conduct an empirical case study on four companies providing 3PL services in Korea. The results indicate that Responsiveness out of the five service quality dimensions is the most important factor in the perception of 3PL customers.
Integrating Analytical Procedures Into the Continuous Audit Environment
Authors: Koskivaara Eija
Published: October 2009

The objective of this article is to show how to embed analytical procedures (AP) into the continuous audit environment. The audit environment is discussed in terms of audit phases, where the role of APs is to obtain evidence for auditors. The article addresses different characteristics of AP techniques. Furthermore, the article compares four different AP techniques to form expectations for the monthly sales values. Two of these techniques are simple quantitative ones, such as the previous year’s value and the mean of the previous years’ values. The advanced quantitative techniques are regression analysis and an artificial neural network (ANN)-based model. In a comparison of the prediction results, the regression analysis and ANN model turn out to be equally good. The development of these kinds of tools is crucial to the continuous audit environment, especially when most data transmission between companies and their stakeholders are moved into the electronic form.
Business Acceptance of Information and Communication Technologies: an Study of the Service Sector
Authors: Ortega Blanca Hernández , Martínez Julio Jiménez , De Hoyos Maria José Martín
Published: October 2009

The aim of this paper is to analyse the level of development reached by some Information and Communication Technologies (ICT) such as web pages, e-mail, EDI, and business management software in the business world. To this end, we have concentrated on the business behaviour of the service sector. Nevertheless, the technological development demanded changes depending on the activity of the firm, so the mediator effect of the industry has been tested in the process of acceptance of innovations. Our results show the technology acceptance process is influenced by the perception of both the usefulness and the ease of use of such innovation. Moreover, the industry effect mediates the technological behaviour of the firm; meanwhile, if the firms performs a “traditional activity”, there are less incentives to implement the innovation.
The Structure of Information for the Process of Strategic Decision Making: a Study Based on the Strategy While in Practise
Authors: Abib Gustavo , Bulgacov Sergio , Do Amorim André Luis Marra
Published: October 2009

This research aims to study the informational structure behavior at the strategic decision process of two cooperatives located in the state of Parana, Brazil. For the referenced analysis it was used the social relation practices emerged between the cooperatives and its cooperated staff and the analysis of the process as a competitive resource. The research kind was multicase one with descriptive and exploratory methodology and data analysis triangulation. The findings showed that the informational structure behavior has differences in use and importance when observed at different moments of the strategic decision process and at different hierarquical levels.
Experimental Evaluation of Wireless Mesh Network with the Intel Classmate PCS
Authors: Garay Jorge R. Beingolea , Hiramatsu Roberto K. , Kofuji Sergio T. , Lopes Roseli de Deus
Published: October 2009

Este artigo apresenta os resultados da avaliação de uma rede mesh empregando o padrão 802.11s e laptops de baixo custo para inclusão digital fabricados pela Intel - os Classmate PCs. Os experimentos de avaliação contemplaram tanto testes em ambientes internos como externos, nos quais foram realizados testes de cobertura da rede e comunicação multihop. Os experimentos realizados mostram uma taxa máxima obtida na transferência de pacotes de 14Mbps e 12Mbps para TCP e UDP, respectivamente, comprovando a viabilidade da solução proposta para o processo de inclusão digital nas escolas públicas.
Analysis of Components and Usability of Webquests Inportuguese Language Available on the Web: Anexploratory Study
Authors: Batista Bottentuit Junior João , Pereira Coutinho Clara
Published: October 2009

Uma WebQuest é um modelo extremamente simples e rico para utilizar o potencial educativo da Web, com fundamento na aprendizagem colaborativa e nos processos de investigação para a construção do saber, que conta hoje com milhares de propostas de educadores das mais diversas partes do mundo. No entanto, muitas das WebQuests disponibilizadas online não obedecem a padrões mínimos de qualidade no nível dos componentes e da usabilidade, ou então, mais não são do que simples folhas de exercícios ou “WebExercises”. Neste artigo foram recenseadas e analisadas 483 WebQuests em língua portuguesa que estavam disponibilizadas online entre Julho e Outubro de 2007. A avaliação incidiu sobre as componentes e sobre alguns indicadores associados à usabilidade. Os resultados revelam que, no que concerne a componentes, as maiores falhas estão na tarefa, nos recursos e na avaliação e, em nível de usabilidade, a maior falha a assinalar é a ausência do “menu” em muitas dos exemplares analisados. Verificou-se ainda que apenas 41% eram verdadeiras WebQuests, constituindo as restantes simples “WebExercises” com atividades rotineiras que não levam o aluno a tirar partido do potencial da Web para a construção do saber.
From Single Grains to Texture
Authors: Yan Kun , Liss Klaus‐Dieter , Garbe Ulf , Daniels John , Kirstein Oliver , Li Huijun , Dippenaar Rian
Published: October 2009

Structural materials, such as metals, ceramics, and their composites are most often polycrystalline. The nature, morphology, and composition of their microstructure determine in large measure the mechanical properties of the final product, and the art to design novel materials is to find particular arrangements which make them harder, more shock absorbing, heat resistant, or self‐recovering upon damage and aging. The understanding of the basic processes and their interplay in a polycrystalline structure are most important for improved simulation of plastic deformation and to predict their thermo‐mechanical behavior.
The effect of mixer properties and fill level on granular flow in a bladed mixer
Authors: Remy Brenda , Glasser Benjamin J. , Khinast Johannes G.
Published: October 2009

The discrete element method was used to study the effect of mixer properties and fill level on the granular flow of monodisperse, cohesionless spheres in a bladed mixer. For fill levels just covering the span of the blades, a three‐dimensional (3‐D) recirculation zone develops in front of the blades, which promotes vertical and radial mixing. Increasing fill level reduces the size of the recirculation zone, decreases bed dilation and hinders particle diffusivities. However, above a critical fill level, the behavior of the particles within the span of the blade is found to be invariant of fill level. At low‐fill levels, the pressure within the particle bed varies linearly with bed height and can be approximated by hydrostatics. At higher fill levels, a constant pressure region develops within the span of the blades due to the angled pitch of the blades. Cylinder wall friction is shown to significantly influence granular behavior in bladed mixers. At low‐wall friction, the 3‐D recirculation zone observed for high‐wall friction conditions does not develop. High‐wall friction leads to an increase in convective and diffusive particle mixing. Shear stresses are shown to be a function of wall friction. Blade position along the vertical axis is shown to influence flow patterns, granular temperature and stress. The effect of increasing the mixer diameter at a constant particle diameter was also studied. When the mixer diameter is larger than a critical size such that wall effects are minimized, the observed granular behavior follows simple scaling relations. Particle velocities and diffusivities scale linearly with mixer size and blade speed. Normal and shear stress profiles are found to scale linearly with the total weight of the particle bed. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Behavior of an organic solvent drop during the supercritical extraction of emulsions
Authors: Mattea Facundo , Martín Ángel , Schulz Constantin , Jaeger Philip , Eggers Rudolf , Cocero María José
Published: October 2009

The behavior of a drop of dichloromethane in water in contact with CO2 at high pressure has been investigated with the purpose of analyzing the phenomena that takes place during the supercritical fluid extraction of emulsions process. Experiments have been performed with and without a solute (β‐carotene) and a surfactant (n‐octenylsuccinic anhydride‐modified starch) dissolved in the drop, and the evolution of the drop volume as well as of the interfacial tension between the drop and the aqueous phase has been measured. Additionally, a mathematical model has been developed that allows describing the mass transfer. Results show that the drop undergoes swelling and shrinking processes due to diffusion of CO2 into the drop and dichloromethane out of the drop. CO2 concentration in the drop can be as high as 0.9 (molar fraction). Emulsion drops behave as miniature gas antisolvent precipitators and many particles are formed inside the drop. The interfacial tension between the drop and the aqueous phase increases during the process, therefore destabilizing the emulsion. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Body size and human energy requirements: Reduced mass‐specific total energy expenditure in tall adults
Authors: Heymsfield Steven B. , Pietrobelli Angelo
Published: October 2009

Mammalian resting energy expenditure (REE) increases as ∼weight0.75 while mass‐specific REE scales as ∼weight−0.25. Energy needs for replacing resting losses are thus less relative to weight (W) in large compared with small mammals, a classic observation with biological implications. Human weight scales as ∼height2 and tall adults thus have a greater weight than their short counterparts. However, it remains unknown if mass‐specific energy requirements are less in tall adults; allometric models linking total energy expenditure (TEE) and weight with height (H) are lacking. We tested the hypothesis that mass‐specific energy requirements scale inversely to height in adults by evaluating TEE (doubly labeled water) data collected by the National Academy of Sciences. Activity energy expenditure (AEE) was calculated from TEE, REE (indirect calorimetry), and estimated diet‐induced energy expenditure. Main analyses focused on nonmorbidly obese subjects ≤50 yrs of age with non‐negative AEE values (n = 404), although results were directionally similar for all samples. Allometric models, including age as a covariate, revealed significantly (P < 0.05) greater REE, AEE, and TEE as a function of height (range H1.5–1.7) in both men and women. TEE/W scaled negatively to height (∼H−0.7, P < 0.01) with predicted mass‐specific TEE (kcal/kg/d) at ±2 SD for US height lower in tall compared with short men (40.3 vs. 46.5) and women (37.7 vs. 42.7). REE/W also scaled negatively to height in men (P < 0.001) and women (P < 0.01). Results were generally robust across several different analytic strategies. These observations reveal previously unforeseen associations between human stature and energy requirements that have implications for modeling efforts and provide new links to mammalian biology as a whole. Am. J. Hum. Biol. 2010. © 2009 Wiley‐Liss, Inc.
Synthesis of 2‐Fluoro N10‐Substituted Acridones and Their Cytotoxicity Studies in Sensitive and Resistant Cancer Cell Lines and Their DNA Intercalation Studies
Authors: Mayur Yergeri C. , Zaheeruddin  , Peters Godefridus J. , Lemos Clara , Kathmann Ietje , Prasad Velivela V. S. Rajendra
Published: October 2009

A series of 2‐fluoro N10‐substituted acridone derivatives with varying alkyl side chain length with propyl, butyl substitution, and a tertiary amine group at the terminal end of the alkyl side chain were synthesized and screened against cancer cell lines SW 1573, SW 1573 2R 160 (P‐gp substrate) which are non‐small lung cancer cell lines, MCF‐7, MCF‐7/MR (BCRP substrate) are breast cancer cell lines, 2008 WT, 2008MRP1, 2008MRP2, 2008MRP3 are ovarian cancer cell lines, and human embryo kidney cell lines like HEK293, HEK293 MRP4, and HEK293 MRP5i. The propyl‐series compounds showed lipophilicity in the range of 1.93 to 4.40 and the butyl series in the range of 2.37 to 4.78. The compounds 4, 7, and 8 showed good cytotoxicity against the 60 human cancer cell line panel of the National Cancer Institute, USA. The compounds 14 and 15 showed a better cytotoxicity in most of the cancer cell lines compared to other compounds tested. The DNA‐binding properties of the compounds were evaluated based on their affinity or intercalation with CT‐DNA measured with absorption titration. The compound 11 bearing planar tricyclic ring linked with a butyl methylpiperazino side chain showed the highest binding affinity with a binding constant (Ki) of 10.38×10 M–1. Evaluation of the compounds in cell lines with an overexpression of various multidrug resistance‐related protein (MRP), P‐glycoprotein (P‐gp), or Breast Cancer Resistance Protein (BCRP) showed that all compounds are not substrates for any of these transporters.
Monitoring the fractionation of a whey protein isolate during dead‐end membrane filtration using fluorescence and chemometric methods
Authors: Elshereef Rand , Budman Hector , Moresoli Christine , Legge Raymond L.
Published: October 2009

During membrane‐based separation of proteins, changes in protein concentration of the permeate and retentate streams occurs over time. The current work proposes a new approach for monitoring the changes in concentrations of proteins in both permeate and retentate by making use of data collected using fluorescence spectroscopy and intrinsic protein fluorescence analyzed by multivariate statistical techniques. Whey protein isolate consists mainly of α‐lactalbumin (α‐LA), β‐lactoglobulin (β‐LG), and small proportion of bovine serum albumin (BSA) and was used as a model system in this study. A fiber optic probe (FOP) was used to acquire multiwavelength fluorescence spectra for permeate and retentate streams at different times during UF‐based separation of the components from a multicomponent solution. Multivariate regression models were developed for predicting the concentrations of α‐LA, β‐LG, and BSA by establishing a calibration model between data acquired using the FOP and the corresponding protein concentration levels measured by size‐exclusion chromatography. The model was validated using FOP data that were not previously used for calibration of the regression models. This comparison showed that concentrations of α‐LA, β‐LG, and BSA could be predicted directly from FOP data within reasonable accuracy by making use of multivariate calibration tools. This approach has several attractive features including that it is nondestructive, fast, and relatively simple to perform. This technique has potential practical applications as it could offer the opportunity for in situ monitoring of membrane filtration processes by tracking individual protein transmission and selectivity of fractionation. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Personal recommendation based on a user's understanding
Authors: Lee Soojung
Published: October 2009

Current web personalization mainly focuses on extracting web pages interesting to users. However, difficulty in understanding web contents often arises for some users mainly due to the lack of background knowledge on the contents. As a solution to this problem, this paper proposes a method of personalizing web search that produces search results suitable to the understanding level of a user. Fuzzy sets and membership functions are defined in order to keep adjusting the level of a user, which is updated based on the levels of web pages on which the user shows preferences. Extensive simulation experiments are conducted to tune the system parameters optimally and to show that the proposed system outperforms not only a general search engine but also a system that updates the understanding level of a user with the mean of the web page levels. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 62–71, 2012
Composite Particles of Novozyme 435 and Silicone: Advancing Technical Applicability of Macroporous Enzyme Carriers
Authors: Wiemann Lars O. , Nieguth René , Eckstein Marrit , Naumann Matthias , Thum Oliver , Ansorge‐Schumacher Marion B.
Published: October 2009

The mechanical and leaching stability of enzymes adsorbed on macroporous carriers is an important issue for the technical applicability of such biocatalysts. Both can considerably benefit from the deposition of silicone coating on the carrier surface. The coating of the immobilized lipase Novozyme 435 (NZ435), as a model enzyme preparation, with different silicone loadings was studied in detail by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), as well as by energy‐dispersive X‐ray spectroscopy (EDX) and BET isotherms, and offers explanations and prerequisites for its stabilizing effects. The deposition of silicone on the poly(methyl methacrylate) (PMMA) carrier was found to form an interpenetrating network composite rather than the anticipated core‐shell structure. The silicone precursors homogeneously wet the carrier surface including all inner pores and gradually fill the complete carrier. In parallel, the surface area of NZ435 decreases from an initial value of 89 m2g−1to 0.2 m2g−1after silicone loading. A visible layer of silicone on the outer surface of the carrier was only observed at a silicone concentration of 54 % w/w and more. Maximum leaching stability corresponds to the formation of this layer. The mechanical stability increases with the amount of deposited silicone. It can be expected that stabilization against leaching and/or mechanical stress by formation of silicone composites can easily be transferred to a whole range of alternative biocatalytic systems. This should considerably advance their general technical applicability and overall implementation of biocatalysts in chemical synthesis.
ChemInform Abstract: Microsolvation of Thiosulfuric Acid and Its Tautomeric Anions [HSSO3]‐ and [SSO2(OH)]‐ Studied by B3LYP‐PCM and G3X(MP2) Calculations.
Authors: Steudel Ralf , Steudel Yana
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Dy5Ni0.66Bi2.34 and Lu5Ni0.56Sb2.44 — Substitution Derivatives with the Orthorhombic Yb5Sb3‐Type Structure. Magnetocaloric Effect of Dy5Ni0.66Bi2.34.
Authors: Svitlyk Volodymyr , Fei Fan , Mozharivskyj Yurij
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis, Crystal and Band Structures, and Optical Properties of a New Supramolecular Complex: [Hg6Sb4](InBr6)Br.
Authors: Zou Jian‐Ping , Guo Sheng‐Ping , Jiang Xiao‐Ming , Liu Guang‐Ning , Guo Guo‐Cong , Huang Jin‐Shun
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Starting Members of the Series Pr4n+2(C2)nBr5n+5 (n = 1, 2, 3).
Authors: Schaloske Manuel Christian , Mattausch Hansjuergen , Duppel Viola , Kienle Lorenz , Simon Arndt
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Chemistry of Three New Monodimensional Fluorometalates Templated with Ethylenediamine.
Authors: Lhoste J. , Gervier R. , Maisonneuve V. , Leblanc M. , Adil K.
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Enantioselective Friedel—Crafts Reactions of Ethenetricarboxylates and Substituted Pyrroles and Furans and Intramolecular Reaction of Benzene Derivatives.
Authors: Yamazaki Shoko , Kashima Shinichi , Kuriyama Taiki , Iwata Yuko , Morimoto Tsumoru , Kakiuchi Kiyomi
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Unusual Methylation Reaction of gem‐ Bromofluorospiropentanes with Methyllithium.
Authors: Averina Elena B. , Sedenkova Kseniya N. , Borisov Ilya S. , Grishin Yuri K. , Kuznetsova Tamara S. , Zefirov Nikolai S.
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Nickel/AlMe2Cl‐Catalyzed Carbocyanation of Alkynes Using Arylacetonitriles.
Authors: Yada Akira , Yukawa Tomoya , Nakao Yoshiaki , Hiyama Tamejiro
Published: October 2009

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.