Tourism and Empirical Applications of International Trade Theory: A Multi-Country Analysis

This paper examines the application of quantitative techniques to further our understanding of international trade theory with respect to tourism flows. The analyses are based on the construction of Balassa and Grubel-Lloyd Indices, as well as the construction of dynamic indices. The results of the analyses suggest that international trade theory has much to offer the study of international tourism flows. Many countries seem to specialize as both exporters and importers of tourism services. The analyses also explore the theoretical assertion that intra-industry trade is likely to be of importance in understanding international tourism flows

Tourism and Empirical Applications of International Trade Theory: A Multi-Country Analysis

This paper examines the application of quantitative techniques to further our understanding of international trade theory with respect to tourism flows. The analyses are based on the construction of Balassa and Grubel-Lloyd Indices, as well as the construction of dynamic indices. The results of the analyses suggest that international trade theory has much to offer the study of international tourism flows. Many countries seem to specialize as both exporters and importers of tourism services. The analyses also explore the theoretical assertion that intra-industry trade is likely to be of importance in understanding international tourism flows

UK Taxes and Tax Revenues: Composition and Trends

This study looks at the composition and trends of tax revenues in the UK. It provides a brief overview of the rather complicated system of different taxes in the UK. Three main taxes—personal income tax, national insurance contributions (NICs) and value added tax (VAT)—are shown to account for about three quarters of all tax revenues and that this has been stable over a period of time. In comparison to other countries the UK is similar in its tax composition to both the US and France, where the same three types of tax dominate revenues. It is much less similar to both Malaysia and Argentina. The study examines monthly UK tax revenues for these three taxes, using econometrically estimated trends. It finds that, in constant price terms, revenues have grown slowly and steadily over time, broadly keeping pace with growth in real GDP. Tax revenue forecasting in the UK is mainly undertaken by an independent body which publishes forecasts at the level of receipts for individual taxes. This considerably reduces the risk of political bias in these revenue forecasts

Development of novel multiplex microsatellite polymerase chain reactions to enable high-throughput population genetic studies of Schistosoma haematobium

© 2015 Webster et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article

Prevalence and distribution of schistosomiasis in human, livestock, and snail populations in northern Senegal: a One Health epidemiological study of a multi-host system

BACKGROUND: Schistosomiasis is a neglected tropical disease of global medical and veterinary importance. As efforts to eliminate schistosomiasis as a public health problem and interrupt transmission gather momentum, the potential zoonotic risk posed by livestock Schistosoma species via viable hybridisation in sub-Saharan Africa have been largely overlooked. We aimed to investigate the prevalence, distribution, and multi-host, multiparasite transmission cycle of Haematobium group schistosomiasis in Senegal, West Africa. METHODS: In this epidemiological study, we carried out systematic surveys in definitive hosts (humans, cattle, sheep, and goats) and snail intermediate hosts, in 2016-18, in two areas of Northern Senegal: Richard Toll and Lac de Guiers, where transmission is perennial; and Barkedji and Linguère, where transmission is seasonal. The occurrence and distribution of Schistosoma species and hybrids were assessed by molecular analyses of parasitological specimens obtained from the different hosts. Children in the study villages aged 5-17 years and enrolled in school were selected from school registers. Adults (aged 18-78 years) were self-selecting volunteers. Livestock from the study villages in both areas were also randomly sampled, as were post-mortem samples from local abattoirs. Additionally, five malacological surveys of snail intermediate hosts were carried out at each site in open water sources used by the communities and their animals. FINDINGS: In May to August, 2016, we surveyed 375 children and 20 adults from Richard Toll and Lac de Guiers, and 201 children and 107 adults from Barkedji and Linguère; in October, 2017, to January, 2018, we surveyed 386 children and 88 adults from Richard Toll and Lac de Guiers, and 323 children and 85 adults from Barkedji and Linguère. In Richard Toll and Lac de Guiers the prevalence of urogenital schistosomiasis in children was estimated to be 87% (95% CI 80-95) in 2016 and 88% (82-95) in 2017-18. An estimated 63% (in 2016) and 72% (in 2017-18) of infected children were shedding Schistosoma haematobium-Schistosoma bovis hybrids. In adults in Richard Toll and Lac de Guiers, the prevalence of urogenital schistosomiasis was estimated to be 79% (52-97) in 2016 and 41% (30-54) in 2017-18, with 88% of infected samples containing S haematobium-S bovis hybrids. In Barkedji and Linguère the prevalence of urogenital schistosomiasis in children was estimated to be 30% (23-38) in 2016 and 42% (35-49) in 2017-18, with the proportion of infected children found to be shedding S haematobium-S bovis hybrid miracidia much lower than in Richard Toll and Lac de Guiers (11% in 2016 and 9% in 2017-18). In adults in Barkedji and Linguère, the prevalence of urogenital schistosomiasis was estimated to be 26% (17-36) in 2016 and 47% (34-60) in 2017-18, with 10% of infected samples containing S haematobium-S bovis hybrids. The prevalence of S bovis in the sympatric cattle population of Richard Toll and the Lac de Guiers was 92% (80-99), with S bovis also found in sheep (estimated prevalence 14% [5-31]) and goats (15% [5-33]). In Barkedji and Linguère the main schistosome species in livestock was Schistosoma curassoni, with an estimated prevalence of 73% (48-93) in sheep, 84% (61-98) in goats and 8% (2-24) in cattle. S haematobium-S bovis hybrids were not found in livestock. In Richard Toll and Lac de Guiers 35% of infected Bulinus spp snail intermediate hosts were found to be shedding S haematobium-S bovis hybrids (68% shedding S haematobium; 17% shedding S bovis); however, no snails were found to be shedding S haematobium hybrids in Barkedji and Linguère (29% shedding S haematobium; 71% shedding S curassoni). INTERPRETATION: Our findings suggest that hybrids originate in humans via zoonotic spillover from livestock populations, where schistosomiasis is co-endemic. Introgressive hybridisation, evolving host ranges, and wider ecosystem contexts could affect the transmission dynamics of schistosomiasis and other pathogens, demonstrating the need to consider control measures within a One Health framework. FUNDING: Zoonoses and Emerging Livestock Systems programme (UK Biotechnology and Biological Sciences Research Council, UK Department for International Development, UK Economic and Social Research Council, UK Medical Research Council, UK Natural Environment Research Council, and UK Defence Science and Technology Laboratory)

Chemical composition of Some Components of the Arrestment Pheromone of the Black-Legged Tick, Ixodes scapularis (Acari : Ixodidae) and Their Use in Tick Control

Chemical analysis (high-performance liquid chromatography) and bioassay demonstrated the presence of compounds that seem to be components of the Ixodes scapularis arrestment pheromone. Only two purines, guanine and xanthine, were found in acidified saline extracts made from cast skins after molting of fed nymphs, fed larvae, and fecal/excretory exudates deposited by unfed adults on substrates in their environment. The ratio of guanine to xanthine was 10.6:1 in an extract from the nymphal skins versus 0.95:1 in an extract from the larval skins. Guanine, xanthine, and traces of a third purine, tentatively identified as 8-azaguanine, were found in extracts made from filter paper strips or washings from glass vials contaminated with tick feces and excreta left by unfed adults. 8-azaguanine may be a product of microbial degradation of the other purines rather than a natural product from the ticks. Low concentrations of ammonia also were detected in saline extracts of excreta from feeding ticks. Hematin also was found in NH4OH extracts of the black fecal/excretory exudates deposited by the unfed ticks. Hematin was tentatively identified by comparison of spectra with that of the authentic standard. Bioassays demonstrated a strong positive arrestment response to cast skins found to contain a mixture of guanine and xanthine and to black fecal/excretory exudates containing guanine, xanthine, the putative 8-azaguanine, and hematin. A Noldus video tracking system using a CCD video camera and Ethovision Pro tracking software showed statistically significant increases in the frequency of visits to the treated zone versus the control. Ticks were significantly more likely to assemble in response to the tick exudates within as little as 3 h compared with the controls. Previous bioassay studies also showed strong positive responses to guanine, xanthine, other purines, and hematin. Comparisons with the arrestment pheromones of other tick species are described. The inclusion of the pheromone components in a permethrin-impregnated oily matrix, Last Call, increased the lethal activity of the product to 95% compared with only 65% in the formulation with permethrin alone. More detailed knowledge of I. scapularis arrestment pheromone may be useful for improving the efficacy of this tick-killing technology even further

The effects of COVID-19 on employment, labor markets, and gender equality in Central America.

This study considers the economic impact of coronavirus disease 2019 (COVID-19) on commercial enterprises in four Central American countries - El Salvador, Guatemala, Honduras, and Nicaragua. At the time of analysis, neither the pandemic nor its economic consequences had fully run their course. It is not, therefore, a definitive analysis, but it is important to try to draw important lessons as soon as possible. The main focus of the study was the initial impact on labor markets. The analysis was based on World Bank Enterprise Surveys undertaken before the outbreak of COVID-19 and follow-up surveys on the effects of the pandemic, also undertaken by the World Bank (Source: Enterprise Surveys, The World Bank, http://www.enterprisesurveys.org). These were combined with data on both government containment measures and rates of morbidity and mortality. The use of enterprise data to analyze labor market issues has some limitations but also many strengths. The data are useful for analyzing the consequences for gender equality in employment. Since the demand for labor is a derived demand, firm-level data provide a clear link to labor market effects. The pandemic has caused a significant loss in sales for many firms. This has created a loss of liquidity, which, in turn, has caused some firms to reduce employment, working hours, and wages. Government containment measures necessary to save lives, such as temporary workplace closures, have added to the burden for both firms and employees. The study starts by using the surveys to identify the important stylized facts. Although some issues are already well documented anecdotally through media reports, this method provides a more evidence-based approach. It also helps identify several issues, such as the impact on gender equality, which has received less journalistic attention. The study is further supported by a regression analysis (ordinary least squares and seemingly unrelated regression equations models) of several key outcomes (changes in sales, employment, the share of females in employment, and expectations of firm survival). A limitation of such an analysis at any enterprise level is heterogeneity and, consequently, a risk of sample selection bias. To provide robustness checks, we use a matching approach. The results suggest that a significant proportion of surviving firms are vulnerable to permanent closure. The ability of firms to retain labor depends on sales, which are affected by both the pandemic itself and the government containment measures. Only a small proportion of firms have received government support, and there is evidence that it could help both firm survival and the retention of labor. There is some doubt whether the four countries have the institutional capacity to provide effective support. If such doubts prove well founded, then support may need to be externally driven

The gender pay gap in the US: a matching study

This study examines the gender wage gap in the US using two separate cross-sections from the Current Population Survey (CPS). The extensive literature on this subject includes wage decompositions that divide the gender wage gap into “explained” and “unexplained” components. One of the problems with this approach is the heterogeneity of the sample data. In order to address the difficulties of comparing like with like this study uses a number of different matching techniques to obtain estimates of the gap. By controlling for a wide range of other influences, in effect, we estimate the direct effect of simply being female on wages. However, a number of other factors, such as parenthood, gender segregation, part-time working and unionization, contribute to the gender wage gap. This means that it is not just the core “like for like” comparison between male and female wages that matters, but also how gender wage differences interact with other influences. The literature has noted the existence of these interactions, but precise or systematic estimates of such effects remain scarce. The most innovative contribution of this study is to do that. Our findings imply that the idea of a single uniform gender pay gap is perhaps less useful than an understanding of how gender wages are shaped by multiple different forces

Social technologies for online learning: theoretical and contextual issues

Three exemplars are presented of social technologies deployed in educational contexts: wikis; a photo-sharing environment; and a social bookmarking tool. Students were found to engage with the technologies selectively, sometimes rejecting them, in the light of their prior conceptions of education. Some students (a minority in all the studies) were unsympathetic to the educational philosophy underpinning the technology’s adoption. The paper demonstrates, through an examination of in-context use, the importance of socio-cultural factors in relation to education, and the non-deterministic nature of educational technology. The academic study of technology has increasingly called into question the deterministic views which are so pervasive in popular discourse and among policy makers. Instead, socio-cultural factors play a crucial role in shaping and defining technology and educational technology is no exception, as the examples in the paper show. The paper concludes by drawing out some implications of the examples for the use of social technologies in education