bluuebunny/crossref_metadata_2025 huggingface dataset:
Forecasting the Tourism Environment Using a Consensus Approach
Authors: Moutinho Luiz , Witt Stephen F.
Published: March 2008

Qualitative techniques are generally used to forecast the long-term tourism environment. Although the Delphi approach is often employed for this purpose, in this study an alternative consensus approach is adopted (on account of the radical nature of some of the possible tourism developments) that permits full discussion among the experts taking part in the forecasting exercise. The results show that the tourism experts expect advances in science and technology to have major impacts on tourism development during the period up to 2030.
Holidays on the Farm: A Case Study of German Hosts and Guests
Authors: Oppermann Martin
Published: March 2008

This study compares hosts' and guests' responses to questions regarding the guests' travel motives, excursions, and perception of the tourist resource base in a farm tourism setting in southern Germany. It shows a high degree of conformity, indicating that hosts have an intimate knowledge of their guests. Further, the article analyzes the economic potential of farm tourism. It suggests that farm tourism often forms only a supplementary income.
The Impact of International Tourism on the Economy of Bermuda, 1994
Authors: Archer Brian
Published: March 2008

This article is concerned with the impact made by international tourism on the economy of Bermuda during 1994, as measured by an input-output model. It is one of a series of similar studies undertaken on behalf of the government of Bermuda to monitor the impact of tourism on incomes, employment, government revenue, and the balance of payments.
Determinants of Tourist Arrivals and Expenditures in Canada
Authors: Hanquin Qiu  , Junsen Zhang
Published: March 2008

This study investigated the determinants and functional forms of international tourism demand for travel to Canada from the United States, the United Kingdom, France, theformer West Germany, and Japan. The independent variables, per capita income, exchange rate, travel price index, immigration, crime rate, special events, and a time trend, were hypothesized to influence tourist arrivals and expenditure. Both linear and log-linear functions were estimated, and a statistical method was applied to choose the appropriate functional form. Overall, with few exceptions, the variables examined explained a high percentage of variations in the dependent variables, and most variables had statistically significant coefficients with expected signs. This study shows that determinants of tourism demand may vary by country, suggesting that pooling data across countries needs to be treated with caution. While there appears to be almost universal agreement that the log-linear form is better than the linear form in the international tourism demand literature, it is shown that the popular view is often not supported by the data.
Choice Factors and Alternative Activities for Riverboat Gamblers
Authors: Turco Douglas M. , Riley Roger W.
Published: March 2008

This study examined the choice factors and alternative activities involved when choosing a particular riverboat casino over its competitors. These factors are considered important in the Chicago metropolitan area where five relatively similar riverboat operations exist in close proximity. Chi-square analyses revealed that the choice factors most important among frequent gamblers were related to service quality; recommendations by friends/ relatives were most influential among occasional gamblers; and among infrequent gamblers the novelty of the riverboat experience was the most important choice factor.
Crime Patterns and Gaming Development in Rural Colorado
Authors: Stokowski Patricia A.
Published: March 2008

Opponents of casino development often claim that gaming development will lead to an increase in community criminal behavior. This article compares crime levels before, during, and after the initiation of gaming in three rural Colorado towns. While totals have increased in some offense categories, crime is not proportional to numbers of tourists visiting. These data illustrate the complexity of competing claims about gaming impacts.
Report on a Comprehensive Five-Year Gambling Impact Research Plan in New Orleans
Authors: Dimanche Frédéric , Speyrer Janet F.
Published: March 2008

Gambling as a recreation and touristic activity is experiencing rapid growth in the United States. However, little research exists on the impact of gambling on communities, particularly in cities with diversified economies. This report presents a plan for an inter disciplinary five-year study of the impacts of riverboat and land-based gambling on the city of New Orleans.
Conference Report . . .
Authors: Goeldner C.R.
Published: March 2008

This report briefly summarizes the 1996 Travel Outlook Forum, cosponsored by the Travel and Tourism Research Association and the Travel Industry Association of America. Copies of the 1996 Outlook for Travel and Tourism are available from the Travel Industry Association of America, 1100 New York Avenue, NW, Suite 450, Washington, DC 20005-3934 for $150.
Visitor Attitudes to a Policy Instrument for Visitor Funding of Conservation in a Tourist Area
Authors: Bramwell Bill , Fearn Adrian
Published: March 2008

This study identified criteria to evaluate the strengths and weaknesses of policy instruments to raise money from visitors to fund environmental conservation in a tourist area. An assessment was made of a proposed local tourism heritage trust, which would fund local conservation based on visitors paying a voluntary small levy on local tourist services in the English Peak District. Results of a survey of visitor attitudes about the trust prior to implementation of activities provided management with information on the trust's feasibility and form and suggested many visitors would pay the levy.
A Profile of the Casino Resort Vacationer
Authors: Morrison Alastair M. , Braunlich Carl G. , Cai Liping A. , O'Leary Joseph T.
Published: March 2008

This article provides profiles of casino resort vacationers and oceanside beach resort, ski resort, and summer country resort vacationers. It investigates the differences between the four groups of travelers. These travelers were found to have different sociodemographics, trip planning characteristics, activity participation patterns, and benefits experienced. A discriminant function was developed to predict resort choice based on four demographic characteristics. Two constructs of travel attitudes were developed that displayed significant differences between casino resort vacationers and other resort groups.
Hybrid Conjoint Analysis as a Research Technique to Measure Meeting Planners' Preferences in Hotel Selection
Authors: Hu Clark , Hiemstra Stephen J.
Published: March 2008

This article addresses the need for measuring meeting planners' preferences of hotel selection to help hotel management better understand their customers' expectations in the meeting business. Using hybrid conjoint analysis (HCA) the authors incorporated meeting planners' trade-offs in the preference measurement to overcome the drawbacks of traditional measurement methods. The HCA methodology is discussed to provide a better under standing of this research technique. This article reports which attributes are considered most important and least important to meeting planners. The most preferred hotel profile in the study was identified as a reference for hotel operators to improve their meeting packages. HCA model validations were carried out to examine the validity of preference prediction. Finally, the authors explain the implications and some limitations of this research.
Current Income versus Total Expenditure Measures in Regression Models of Vacation and Pleasu re Travel
Authors: Fish Mary , Waggle Doug
Published: March 2008

This study compares the impact that life cycle income and current income have on the number of vacation and pleasure trips taken and trip expenditures of families. Total household expenditure is used as a surrogate for permanent or life cycle income. A stratified sample was taken from the U.S. Department of Labor consumer survey data. The impact of additional variables such as age of consumer unit, reference person, and number of old and young people in the household is also evaluated. The percentage spent on trips increases as the total expenditure quintile rises, while the percentage spent on trips decreases as the income quintile increases. Total household expenditures is the strongest variable for forecasting trips and the spending on them.
Using the Internet for Travel and Tourism Survey Research: Experiences from the Net Traveler Survey
Authors: Schonland Addison M. , Williams Peter W.
Published: March 2008

This article presents some of the 1995-96 first-year preliminary findings of the Net Traveler Survey, a pioneering and ongoing study of the travel and tourism characteristics of Internet users. The focus is on the strengths and challenges associated with using the Internet as a medium for primary survey research purposes. The article provides tourism market researchers and managers with useful guidelines concerning survey design and operational issues, such as addressing sample bias, weighting samples, and improving survey effectiveness and efficiency for respondents, clients, and research organizations. The article contributes to the growing body of knowledge associated with the methodological development of survey design and implementation strategies for using this rapidly evolving medium.
Improving the Accuracy of Hotel Reservations Forecasting: Curves Similarity Approach
Authors: Schwartz Zvi , Hiemstra Stephen
Published: March 2008

This study developed and tested a new type of an extrapolative forecasting model that improves the forecasting models of daily occupancy levels in a hotel by focusing on the shape of past booking curves. By applying a dissimilarity measure to identify past book ing curves with a similar shape, the identified similar curves were then used to project future reservations. The study examined 10 forecasting horizons ranging from 1 to 99 days in advance. The results indicate that the curves similarity model is considerably more accurate than the three benchmark models tested These results are statistically and prac tically significant. In addition, this study shows that under certain conditions a model that combines two independent models might produce a forecast that is more accurate than that of its components.
Mexico's 1989-94 Tourism Plan: Implications of Internal Political and Economic Instability
Authors: Casado Matt A.
Published: March 2008

This article is a descriptive study of the tourism modernization plan adopted and implemented by Mexico as a means of improving the economic performance of the country. It presents in detail the strategies adopted and the steps taken by the Mexican government to carry out the plan, analyzes the results, and argues that although a well- designed and well-executed tourism plan is necessary, it may not be sufficient for developing sustained growth when political and economic instability are present.
The Development of the Cruise Line Job Satisfaction Questionnaire
Authors: Testa Mark R. , Williams John M. , Pietrzak Dale
Published: March 2008

This article discusses the development and testing of the 31-item Cruise Line Job Satisfaction Questionnaire (CLJSQ). The CLJSQ measures three facets of job satisfac tion in the cruise industry, including satisfaction with company, supervisor, and ship. This investigation used four se quential experiments to assess the CLJSQ's content validity, test-retest reliability, criterion-related validity, and construct validity, in addition to the instrument's internal consistency. The procedures and process used in this study may provide a useful example for researchers seeking to validate measurement scales or questionnaires. The results show the CLJSQ to be a valid and reliable instrument for measuring job satisfaction in the cruise industry.
Tracking Expenditures of the Elusive Nature Tourists of Southeastern Arizona
Authors: Leones Julie , Colby Bonnie , Crandall Kristine
Published: March 2008

Expansion of nature tourism markets may be limited because of restrictions on visitor numbers at specific sites. Hence, factors affecting visitor expenditures are critical. This study of nature tourists in Arizona indicates that bird-watchers spend more money than other visitors to natural sites. Communities that target nature visitors from areas more than a few hours' drive away and encourage visits to multiple sites can increase visitor expenditures.
Industrial Heritage Tourism at the Bingham Canyon Copper Mine
Authors: Rudd Michelle Andreadakis , Davis James A.
Published: March 2008

Industrial tourism is a popular subsection of the heritage tourism industry. Although many companies create tourism sites to increase profits, the Kennecott Utah Copper Corporation uses tourism as a public relation tool to generate a positive image of the copper industry and to counteract public fears about pollution and environmental degradation.
Measuring the Returns to Tourism Advertising
Authors: Butterfield David W. , Deal Kenneth R. , Kubursi Atif A.
Published: March 2008

A framework for estimating the impact of tourism adver tising on tourist spending is developed and implemented for the 1987-88 Ontario Incredible advertising campaign. Tour ism advertising was first linked to changes in awareness of and attitudes toward the target destination based on adver tising tracking data. Second, the changes in awareness and attitudes were linked to changes in the number of visits, based on LISREL and econometric analysis of the tracking data. Finally, changes in the number of visits were converted into changes in tourist expenditures, based on data on actual visits and expenditures. The results suggest that the returns to the advertising campaign were significant. A number of important weaknesses in the implementation are identified, together with the data that would be required to strengthen the estimates.
The Impact of Tourism and Travel Experience on Senior Travelers' Psychological Well-Being
Authors: Milman Ady
Published: March 2008

This study explored the impact of travel and tourism ex perience on travelers' psychological well-being or level of happiness. Using a pretest-posttest experimental design, senior travelers taking an escorted tour were asked to assess their happiness before and after the tour. While the findings rejected the hypothesis that travel may change level ofhappi ness, other variables may explain the variation.
Determining Future Travel Behavior from Past Travel Experience and Perceptions of Risk and Safety
Authors: Sönmez Sevil F. , Graefe Alan R.
Published: March 2008

This study examined the influences of past international travel experience, types of risk associated with international travel, and the overall degree of safety felt during interna tional travel on individuals' likelihood of travel to various geographic regions on their next international vacation trip or avoidance of those regions due to perceived risk. Informa tion integration theory and protection motivation theory served as the theoretical framework for the study. A mail sur vey sent to 500 international travelers achieved a 48% re sponse rate. Nonresponse bias was tested with telephone in terviews. Data were analyzed using cross tabulations and logistic regression. Results revealed that past travel experi ence to specific regions both increases the intention to travel there again and decreases the intention to avoid areas, par ticularly risky areas. Perceived risks and safety were both found to be stronger predictors of avoiding regions than of planning to visit them.
The Symmetry Between Bruno Latour and Martin Heidegger
Authors: Riis Søren
Published: March 2008

In spite of Bruno Latour's explicit critique of Martin Heidegger's conception of technology, he and Heidegger implicitly think very similarly. When looked at carefully, Latour's examination of technical mediation stands out as a detailed reflection of Heidegger's studies. In Pandora's Hope, Latour (1999) dedicates a whole essay to exposing Heidegger's misconception of technology. 1 However, at the end of this polemic, Latour in fact unfolds and actualizes Heidegger's argument. What Latour considers fictitious, antiquated and pessimistic in Heidegger's writings on technology comes alive in a different and more accessible way in his own writings. This profound and previously unrevealed relationship between Latour and Heidegger makes it possible to reinterprete the ideas of both in a way that has crucial importance for Science and Technology Studies (STS). In order to carry out this kind of comparative philosophy or `theoretical fieldwork', one has to pay close attention to their basic conceptions and not be led astray by different ways of naming them.
Medical Science in the Light of the Holocaust
Authors: Hedfors Eva
Published: March 2008

In scholarly debates, Ludwik Fleck's post-war paper `Problemy naukoznawstwa [Problems of the Science of Science]', published in 1946, has been taken unanimously to illustrate the epistemology expounded in his monograph Genesis and Development of a Scientific Fact. The paper has also been seen to support parts of the received view of Fleck, notably that he manufactured an anti-typhus vaccine while imprisoned in Buchenwald. However, a different narrative emerges when comparing Fleck's paper with other accounts, also published in 1946 and written by other prisoners alluded to by Fleck in his paper. The situation is further complicated by four papers, published in prestigious scientific journals between 1942 and 1945, by the German medical leader of the typhus studies accounted for by Fleck. In addition, a thus-far neglected paper by Fleck, published in 1946 and summarizing his observations on typhus, discloses his role in the Buchenwald studies. Despite the obvious difficulties with tracing the history behind these works, notably the one on Nazi science, the contention is that what was attempted in Buchenwald in the name of science amounted to pseudoscience. This conclusion is amply supported not only by the accounts given by Fleck's fellow prisoners, but also by his own post-war paper on typhus. Based on the above findings, it is suggested that the mythology about Fleck, established in the 1980s, has been accomplished by a selective reading of his papers and also that the role played by Fleck was more complex than has so far been contemplated.
Visions and Versions of Governing Biomedicine
Authors: Felt Ulrike , Fochler Maximilian , Mager Astrid , Winkler Peter
Published: March 2008

In recent years, governance and public participation have developed into key notions within both policy discourse and academic analysis. While there is much discussion on developing new modes of governance and public participation, little empirical attention is paid to the public's perception of models, possibilities and limits of participation and governance. Building on focus group data collected in Austria within the framework of a European project, this paper explores lay people's visions and versions of government, governance and participation for two biomedical technologies: post-natal genetic testing and organ transplantation. Building on this analysis, we show that people situate their assessments of public participation against the background of rather complex lay models of the governance and government of the respective technology. Because these models are very different for the two technologies, participation also had very different connotations, which were deeply intertwined with each socio-technical system. Building on these findings we argue for a more technology-sensitive approach to public participation.
Are the poor socially integrated? The link between poverty and social support in different welfare regimes
Authors: Böhnke Petra
Published: March 2008

Cultures of support vary across enlarged Europe. This article examines the link between poverty and social integration in countries characterized by different economic, cultural and welfare state regimes. Its object is to determine whether being materially disadvantaged increases the likelihood of social disintegration (accumulation) or whether poor people can count on receiving more support (compensation). In addition it will examine the conditions under which material and social disadvantages accumulate. The empirical analysis thus combines a micro- with a macro-sociological perspective and focuses particular attention on the context in which people are poor. Although poverty is closely connected to social disintegration, the degree of accumulation varies from one country to the next. Of decisive importance is household composition, which is strongly related to country-specific social policy design. Contextual factors such as the prevalence of poverty also play a role, as do general attitudes to religion and family solidarity.
Early Detection of Pitting Damage in Gears using Mean Frequency of Scalogram
Authors: Öztürk Hasan , Sabuncu Mustafa , Yesilyurt Isa
Published: March 2008

A local gear-tooth defect such as a fatigue crack, pit or chip weakens the tooth and causes transient events when that faulty tooth is in mesh. The magnitude and duration of these events depend mainly upon the severity of the defect and the contact ratio of the gear pair. If the tooth fault severity is small and the contact ratio is high, the resulting transient may not show distinctively in the vibration signal; time-frequency analysis can be used to reveal such events. This paper presents the use of a scalogram and its mean frequency variation for the detection and monitoring of pitting faults in gears. Real gear vibrations are obtained from a test rig utilising a two-stage industrial gearbox. Pits representing differing degrees of fault severity are simulated on a few tooth surfaces. Classical processing schemes in the time and frequency domain are firstly employed to obtain general characteristics of the gear vibration. The continuous wavelet transform is then used to obtain a scalogram and its mean frequency variation. It has been found that the presence of a pitting fault cannot be clearly revealed by the time and frequency domain representations unless the fault severity is high. In contrast, the scalogram (and especially its mean frequency variation) provides early indications of presence and progression of pitting faults in gears even when the fault severity is considerably smaller.
Time-Optimal De-tumbling Control of a Rigid Spacecraft
Authors: Yang Chi-Ching , Wu Chia-Ju
Published: March 2008

The problem of time-optimal de-tumbling control (TODTC) of a rigid spacecraft moving between two attitudes is studied in this article. Unlike conventional approaches, which involve solving a set of differential equations, a novel numerical method is introduced. In the proposed method, by fixing the count of control steps and treating the sampling period as a variable, the TODTC problem is formulated as a nonlinear programming (NLP) problem by utilizing an iterative procedure. Generating initial feasible solutions systematically is also discussed, since these are usually needed in solving a NLP problem. In this manner, the optimization process of the NLP problem can be started from many different points when searching for the optimal solution. Simulation results are included, to show the feasibility of the proposed method.
Active Control of Flow-Induced Vibrations via Feedback Decoupling
Authors: Yigit F.
Published: March 2008

This paper deals with the flutter instability characteristics of a cantilever pipe conveying fluid flow, and explores the applicability of an active nodal vibration control for suppressing the associated structural vibration. The Euler-Bernoulli theory is used to represent pipe bending. The finite element method is used to discretize the governing equation. The control law is based on full state feedback and pole assignment, and requires as many actuators as the number of nodal degrees-of-freedom. Considering that this is not practical, a reduced order model with less number of elements is used to design the controller, and the resulting control input is applied to the “full” or the “truth” model. In this case, since the feedback simplification will not be complete, some performance degradation is to be expected. It is however demonstrated that the proposed control strategy can ensure closed loop stability for a wide range of flow velocity even if the critical flow velocity is exceeded. The effectiveness of the proposed method, in damping out the pipe vibrations, is also demonstrated clearly by comparing its results with those obtained by a direct velocity feedback control which is equivalent to add an external viscous damper to the pipe. The proposed control is essentially a model-based controller, and hence suffers from modeling errors and uncertainties in model parameters. Therefore, the robustness of the control is also investigated. It is shown that the proposed controller significantly reduces sensitivity of the uncontrolled system to flow conditions. It works effectively to suppress the vibrations of a fluid conveying cantilever pipe due to any disturbance.
Putting words in their mouths: The role of teaching assistants and the spectre of scripted pedagogy
Authors: Gibson Howard , Patrick Helen
Published: March 2008

National governments in Britain have consistently promised that, while they would legislate for a curriculum, it would not tell teachers how to teach. Our article suggests, however, that this policy is compromised with the current programme to `remodel the workforce' and augment the role of the classroom or teaching assistant. It does this in three ways. First, it examines the likelihood that what a teacher is may subtly change and overlap with the TA's new role. Second, it argues that despite what the government says, TAs will have little professional authority to question centrally determined initiatives regarding methods and approaches to teaching. And third, it takes a detailed and critical look at recommendations for teaching and learning contained within the government's publication Additional Literacy Support . This national programme for seven-year-old pupils comes complete with `Example Scripts' that are said to model `a perfect lesson' for TAs to imitate. We reflect upon these scripted lessons in detail, suggest that their view of perfection is at best contentious and conclude with the possibility that TAs may increasingly come to serve as a conduit for a centrally contrived pedagogy.
'Third spaces' are interesting places: Applying 'third space theory' to nursery-aged children's constructions of themselves as readers
Authors: Levy Rachael
Published: March 2008

Based on Moje et al.'s (2004) conceptions of `third space theory', this article describes how five nursery-aged children created a `third space' between home and school, in order to find continuity between home and school constructions of reading. This article describes how the children used various aspects of their home experiences, such as popular culture, television texts, computer technology and play to integrate the reading experiences of the home with that of the primary school curriculum. Yet this article also warns that many of these children's own sophisticated and valuable constructions could be at risk of disruption by the demands of the primary school curriculum, even from the time of entry into the Nursery year. It is therefore argued that educators within the Foundation Stage must find ways to accommodate and utilize children's own constructions of reading in order to build confidence and initiate success in a modern generation of young readers.
Impacts of television viewing on young children's literacy development in the USA: A review of the literature
Authors: Moses Annie M.
Published: March 2008

Television viewing plays an important role in the lives of many young children and has received a great deal of attention in the public as well as in research. This review examined research on television and literacy development in early childhood, including studies of messages about literacy in children's programs as well as the impact of specific programs on young viewers' literacy development. Results indicate: (1) moderate amounts of television viewing were found to be beneficial for reading; (2) the content of programs viewed by children matters; (3) programs that aim to promote literacy in young children have been found to positively impact specific early literacy skills; and finally, (4) there are limitations to the existing literature. Suggestions for addressing these limitations were included, and future studies should focus on methodological, theoretical, and measurement issues in this area, in addition to exploring a wider variety of programs watched by young viewers.
An exploration of the experiences of South Asian students on Pre-registration nursing programmes in a UK university
Authors: Dyson Sue , Culley Lorraine , Norrie Peter , Genders Nicky
Published: March 2008

Abstract

There is a lack of focused research on the educational experience of minority ethnic nursing students in the United Kingdom. This small scale mixed–method study has shown that in one institution, South Asian students entered training at a younger age than White students but had broadly similar levels of attainment and completion. Qualitative data suggest that although South Asian and White students share many common experiences, the cultural background of South Asian students may have a considerable effect on their academic life, sometimes creating particular tensions and difficulties. Several themes are explored, including choosing nursing, negotiating marriage, responding to family obligations, relating to fellow students and accessing support. Students expressed the importance of peer group and personal tutor support to their academic success. Understanding the student experience is important and should help institutions to develop culturally sensitive support systems.
Chromhome: A rich internet application for accessing comparative chromosome homology maps
Authors: Nagarajan Sridevi , Rens Willem , Stalker James , Cox Tony , Ferguson-Smith Malcolm A
Published: March 2008

Background

Comparative genomics has become a significant research area in recent years, following the availability of a number of sequenced genomes. The comparison of genomes is of great importance in the analysis of functionally important genome regions. It can also be used to understand the phylogenetic relationships of species and the mechanisms leading to rearrangement of karyotypes during evolution. Many species have been studied at the cytogenetic level by cross species chromosome painting. With the large amount of such information, it has become vital to computerize the data and make them accessible worldwide. Chromhome http://www.chromhome.org is a comprehensive web application that is designed to provide cytogenetic comparisons among species and to fulfil this need.

Results

The Chromhome application architecture is multi-tiered with an interactive client layer, business logic and database layers. Enterprise java platform with open source framework OpenLaszlo is used to implement the Rich Internet Chromhome Application. Cross species comparative mapping raw data are collected and the processed information is stored into MySQL Chromhome database. Chromhome Release 1.0 contains 109 homology maps from 51 species. The data cover species from 14 orders and 30 families. The homology map displays all the chromosomes of the compared species as one image, making comparisons among species easier. Inferred data also provides maps of homologous regions that could serve as a guideline for researchers involved in phylogenetic or evolution based studies.

Conclusion

Chromhome provides a useful resource for comparative genomics, holding graphical homology maps of a wide range of species. It brings together cytogenetic data of many genomes under one roof. Inferred painting can often determine the chromosomal homologous regions between two species, if each has been compared with a common third species. Inferred painting greatly reduces the need to map entire genomes and helps focus only on relevant regions of the chromosomes of the species under study. Future releases of Chromhome will accommodate more species and their respective gene and BAC maps, in addition to chromosome painting data. Chromhome application provides a single-page interface (SPI) with desktop style layout, delivering a better and richer user experience.
Time-course analysis of genome-wide gene expression data from hormone-responsive human breast cancer cells
Authors: Mutarelli Margherita , Cicatiello Luigi , Ferraro Lorenzo , Grober Olì MV , Ravo Maria , Facchiano Angelo M , Angelini Claudia , Weisz Alessandro
Published: March 2008

Background

Microarray experiments enable simultaneous measurement of the expression levels of virtually all transcripts present in cells, thereby providing a ‘molecular picture’ of the cell state. On the other hand, the genomic responses to a pharmacological or hormonal stimulus are dynamic molecular processes, where time influences gene activity and expression. The potential use of the statistical analysis of microarray data in time series has not been fully exploited so far, due to the fact that only few methods are available which take into proper account temporal relationships between samples.

Results

We compared here four different methods to analyze data derived from a time course mRNA expression profiling experiment which consisted in the study of the effects of estrogen on hormone-responsive human breast cancer cells. Gene expression was monitored with the innovative Illumina BeadArray platform, which includes an average of 30-40 replicates for each probe sequence randomly distributed on the chip surface. We present and discuss the results obtained by applying to these datasets different statistical methods for serial gene expression analysis. The influence of the normalization algorithm applied on data and of different parameter or threshold choices for the selection of differentially expressed transcripts has also been evaluated. In most cases, the selection was found fairly robust with respect to changes in parameters and type of normalization. We then identified which genes showed an expression profile significantly affected by the hormonal treatment over time. The final list of differentially expressed genes underwent cluster analysis of functional type, to identify groups of genes with similar regulation dynamics.

Conclusions

Several methods for processing time series gene expression data are presented, including evaluation of benefits and drawbacks of the different methods applied. The resulting protocol for data analysis was applied to characterization of the gene expression changes induced by estrogen in human breast cancer ZR-75.1 cells over an entire cell cycle.
A three-state prediction of single point mutations on protein stability changes
Authors: Capriotti Emidio , Fariselli Piero , Rossi Ivan , Casadio Rita
Published: March 2008

Background

A basic question of protein structural studies is to which extent mutations affect the stability. This question may be addressed starting from sequence and/or from structure. In proteomics and genomics studies prediction of protein stability free energy change (ΔΔG) upon single point mutation may also help the annotation process. The experimental ΔΔG values are affected by uncertainty as measured by standard deviations. Most of the ΔΔG values are nearly zero (about 32% of the ΔΔG data set ranges from −0.5 to 0.5 kcal/mole) and both the value and sign of ΔΔG may be either positive or negative for the same mutation blurring the relationship among mutations and expected ΔΔG value. In order to overcome this problem we describe a new predictor that discriminates between 3 mutation classes: destabilizing mutations (ΔΔG<−1.0 kcal/mol), stabilizing mutations (ΔΔG>1.0 kcal/mole) and neutral mutations (−1.0≤ΔΔG≤1.0 kcal/mole).

Results

In this paper a support vector machine starting from the protein sequence or structure discriminates between stabilizing, destabilizing and neutral mutations. We rank all the possible substitutions according to a three state classification system and show that the overall accuracy of our predictor is as high as 56% when performed starting from sequence information and 61% when the protein structure is available, with a mean value correlation coefficient of 0.27 and 0.35, respectively. These values are about 20 points per cent higher than those of a random predictor.

Conclusions

Our method improves the quality of the prediction of the free energy change due to single point protein mutations by adopting a hypothesis of thermodynamic reversibility of the existing experimental data. By this we both recast the thermodynamic symmetry of the problem and balance the distribution of the available experimental measurements of free energy changes. This eliminates possible overestimations of the previously described methods trained on an unbalanced data set comprising a number of destabilizing mutations higher than stabilizing ones.
In silico docking of urokinase plasminogen activator and integrins
Authors: Degryse Bernard , Fernandez-Recio Juan , Citro Valentina , Blasi Francescol , Cubellis Maria Vittoria
Published: March 2008

Background

Urokinase, its receptor and the integrins are functionally associated and involved in regulation of cell signaling, migration, adhesion and proliferation. No structural information is available on this potential multimolecular complex. However, the tri-dimensional structure of urokinase, urokinase receptor and integrins is known.

Results

We have modeled the interaction of urokinase on two integrins, αIIbβ3 in the open configuration and αvβ3 in the closed configuration. We have found that multiple lowest energy solutions point to an interaction of the kringle domain of uPA at the boundary between α and β chains on the surface of the integrins. This region is not far away from peptides that have been previously shown to have a biological role in urokinase receptor/integrins dependent signaling.

Conclusions

We demonstrated that in silico docking experiments can be successfully carried out to identify the binding mode of the kringle domain of urokinase on the scaffold of integrins in the open and closed conformation. Importantly we found that the binding mode was the same on different integrins and in both configurations. To get a molecular view of the system is a prerequisite to unravel the complex protein-protein interactions underlying urokinase/urokinase receptor/integrin mediated cell motility, adhesion and proliferation and to design rational in vitro experiments.
Minimising barriers to dental care in older people
Authors: Borreani Elena , Wright Desmond , Scambler Sasha , Gallagher Jennifer E
Published: March 2008

Background

Older people are increasingly retaining their natural teeth but at higher risk of oral disease with resultant impact on their quality of life. Socially deprived people are more at risk of oral disease and yet less likely to take up care. Health organisations in England and Wales are exploring new ways to commission and provide dental care services in general and for vulnerable groups in particular. This study was undertaken to investigate barriers to dental care perceived by older people in socially deprived inner city area where uptake of care was low and identify methods for minimising barriers in older people in support of oral health.

Methods

A qualitative dual-methodological approach, utilising both focus groups and individual interviews, was used in this research. Participants, older people and carers of older people, were recruited using purposive sampling through day centres and community groups in the inner city boroughs of Lambeth, Southwark and Lewisham in South London. A topic guide was utilised to guide qualitative data collection. Informants' views were recorded on tape and in field notes. The data were transcribed and analysed using Framework Methodology.

Results

Thirty-nine older people and/or their carers participated in focus groups. Active barriers to dental care in older people fell into five main categories: cost, fear, availability, accessibility and characteristics of the dentist. Lack of perception of a need for dental care was a common 'passive barrier' amongst denture wearers in particular. The cost of dental treatment, fear of care and perceived availability of dental services emerged to influence significantly dental attendance. Minimising barriers involves three levels of action to be taken: individual actions (such as persistence in finding available care following identification of need), system changes (including reducing costs, improving information, ensuring appropriate timing and location of care, and good patient management) and societal issues (such as reducing isolation and loneliness). Older people appeared to place greater significance on system and societal change than personal action.

Conclusion

Older people living within the community in an inner city area where NHS dental care is available face barriers to dental care. Improving access to care involves actions at individual, societal and system level. The latter includes appropriate management of older people by clinicians, policy change to address NHS charges; consideration of when, where and how dental care is provided; and clear information for older people and their carers on available local dental services, dental charges and care pathways.
Hypoxia induces protection against etoposide-induced apoptosis: molecular profiling of changes in gene expression and transcription factor activity
Authors: Sermeus Audrey , Cosse Jean-Philippe , Crespin Marianne , Mainfroid Veronique , de Longueville Francoise , Ninane Noelle , Raes Martine , Remacle Jose , Michiels Carine
Published: March 2008

Background

it is now well established that hypoxia renders tumor cells resistant to radio- but also chemotherapy. However, few elements are currently available as for the mechanisms underlying this protection.

Results

in this study, physiological hypoxia was shown to inhibit apoptosis induced in HepG2 cells by etoposide. Indeed, hypoxia reduced DNA fragmentation, caspase activation and PARP cleavage. The DNA binding activity of 10 transcription factors was followed while the actual transcriptional activity was measured using specific reporter plasmids. Of note is the inhibition of the etoposide-induced activation of p53 under hypoxia. In parallel, data from low density DNA microarrays indicate that the expression of several pro- and anti-apoptotic genes was modified, among which are Bax and Bak whose expression profile paralleled p53 activity. Cluster analysis of data unravels several possible pathways involved in the hypoxia-induced protection against etoposide-induced apoptosis: one of them could be the inhibition of p53 activity under hypoxia since caspase 3 activity parallels Bax and Bak expression profile. Moreover, specific downregulation of HIF-1α by RNA interference significantly enhanced apoptosis under hypoxia possibly by preventing the hypoxia mediated decrease in Bak expression without altering Bax expression.

Conclusion

these results are a clear demonstration that hypoxia has a direct protective effect on apoptotic cell death. Moreover, molecular profiling points to putative pathways responsible for tumor growth in challenging environmental conditions and cancer cell resistance to chemotherapeutic agents.
Human-machine interfaces based on EMG and EEG applied to robotic systems
Authors: Ferreira Andre , Celeste Wanderley C , Cheein Fernando A , Bastos-Filho Teodiano F , Sarcinelli-Filho Mario , Carelli Ricardo
Published: March 2008

Background

Two different Human-Machine Interfaces (HMIs) were developed, both based on electro-biological signals. One is based on the EMG signal and the other is based on the EEG signal. Two major features of such interfaces are their relatively simple data acquisition and processing systems, which need just a few hardware and software resources, so that they are, computationally and financially speaking, low cost solutions. Both interfaces were applied to robotic systems, and their performances are analyzed here. The EMG-based HMI was tested in a mobile robot, while the EEG-based HMI was tested in a mobile robot and a robotic manipulator as well.

Results

Experiments using the EMG-based HMI were carried out by eight individuals, who were asked to accomplish ten eye blinks with each eye, in order to test the eye blink detection algorithm. An average rightness rate of about 95% reached by individuals with the ability to blink both eyes allowed to conclude that the system could be used to command devices. Experiments with EEG consisted of inviting 25 people (some of them had suffered cases of meningitis and epilepsy) to test the system. All of them managed to deal with the HMI in only one training session. Most of them learnt how to use such HMI in less than 15 minutes. The minimum and maximum training times observed were 3 and 50 minutes, respectively.

Conclusion

Such works are the initial parts of a system to help people with neuromotor diseases, including those with severe dysfunctions. The next steps are to convert a commercial wheelchair in an autonomous mobile vehicle; to implement the HMI onboard the autonomous wheelchair thus obtained to assist people with motor diseases, and to explore the potentiality of EEG signals, making the EEG-based HMI more robust and faster, aiming at using it to help individuals with severe motor dysfunctions.
Corticosterone Levels in the Brain Show a Distinct Ultradian Rhythm but a Delayed Response to Forced Swim Stress
Authors: Droste Susanne K. , de Groote Lotte , Atkinson Helen C. , Lightman Stafford L. , Reul Johannes M. H. M. , Linthorst Astrid C. E.
Published: March 2008

Circulating corticosterone levels show an ultradian rhythm resulting from the pulsatile release of glucocorticoid hormone by the adrenal cortex. Because the pattern of hormone availability to corticosteroid receptors is of functional significance, it is important to determine whether there is also a pulsatile pattern of corticosterone concentration within target tissues such as the brain. Furthermore, it is unclear whether measurements of plasma corticosterone levels accurately reflect corticosterone levels in the brain. Given that the hippocampus is a principal site of glucocorticoid action, we investigated in male rats hippocampal extracellular corticosterone concentrations under baseline and stress conditions using rapid-sampling in vivo microdialysis. We found that hippocampal extracellular corticosterone concentrations show a distinct circadian and ultradian rhythm. The PULSAR algorithm revealed that the pulse frequency of hippocampal corticosterone is 1.03 ± 0.07 pulses/h between 0900 and 1500 h and is significantly higher between 1500 and 2100 h (1.31 ± 0.05). The hippocampal corticosterone response to stress is stressor dependent but resumes a normal ultradian pattern rapidly after the termination of the stress response. Similar observations were made in the caudate putamen. Importantly, simultaneous measurements of plasma and hippocampal glucocorticoid levels showed that under stress conditions corticosterone in the brain peaks 20 min later than in plasma but clears concurrently, resulting in a smaller exposure of the brain to stress-induced hormone than would be predicted by plasma hormone concentrations. These data are the first to demonstrate that the ultradian rhythm of corticosterone is maintained over the blood-brain barrier and that tissue responses cannot be reliably predicted from the measurement of plasma corticosterone levels.