AIMS Geosciences最新文献

{"title":"Young returnees' sustainability of return: The case of Bulgaria","authors":"M. Misheva, Antoaneta Getova","doi":"10.3934/geosci.2023023","DOIUrl":"https://doi.org/10.3934/geosci.2023023","url":null,"abstract":"Return migration flow to Bulgaria is constant but not high, except for the past two years. Here, we argue that subjective and objective reasons should both be considered in line to explain life prospects of young returnees at home. An innovative approach to balancing the subjective-objective dichotomy in return migration phenomena is measuring sustainability of return through re-emigration, captured by and tested through a re-emigration index based on a national representative survey of returning Bulgarian migrants. The main hypothesis is that the sustainability of the return of young people depends on a complex group of factors, including social and emotional motives. The main findings are about the magnitude of the return migration flow and its sustainability: The factors for the return of young Bulgarians in the pre-Covid research show strong non-economic character, which intensifies in times of crisis. There are no significantly different tendencies for re-emigration/return among young people compared with all returnees.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70251194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flood spatial location in a Mediterranean coastal city: Ibiza (Balearic Islands) from 2000 to 2021","authors":"Joan Rosselló-Geli, M. Grimalt-Gelabert","doi":"10.3934/geosci.2023013","DOIUrl":"https://doi.org/10.3934/geosci.2023013","url":null,"abstract":"Floods are a common occurrence in the Western Mediterranean basin, causing daily life disturbances, economic impacts and fatalities as the population living near the Mediterranean shores face a great risk. The city of Ibiza has been historically affected by floods of different magnitudes. After almost three decades without large events, with the 1977 flood being the latest, 20 floods have been identified within the city boundaries since the beginning of the 21st century, causing a great social impact. The aim of the research herein presented is to identify the locations of floods and their possible causes. The methodology is based on a comprehensive survey of newspapers articles and technical reports, thus allowing mapping of the location of the events over a city map. Among the causes, there are the lack of a runoff network and deficient infrastructure planning. Regarding the spatial distribution of floods, the most affected areas are the circumvallation freeways around the city and the neighborhoods urbanized after the 1960's. The results highlight the importance of the urban sprawl and malpractices related to flood risk areas, which increase the occurrence of floods. Moreover, the identification of the most affected areas can help city planners to create prevention measures and systems to reduce flood hazards and vulnerability.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70250574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bulgarian community in Chicago: A model of development","authors":"Dilyana Ivanova Zieske, William F. Zieske","doi":"10.3934/geosci.2023029","DOIUrl":"https://doi.org/10.3934/geosci.2023029","url":null,"abstract":"This paper presents the first comprehensive model of development of the Bulgarian settlement in the Chicago area from its earliest traces to the present day, from historical and anthropological perspectives. In the process, we distinguish five periods of Bulgarian presence spanning more than a century and discuss the patterns of Bulgarian settlement, economic profiles and community life for each of those periods. The paper highlights the struggle for survival and recognition of early Bulgarian migrants during the late nineteenth and early twentieth century, the political rivalry of the Cold War Bulgarian refugees preventing their consolidation and the contemporary, post-1989, Bulgarian economic mass migration which becomes increasingly visible and emancipated, claiming Chicago as the Bulgarian City. In the process, we seek to explain why this long history of Bulgarian immigration has not resulted in the community's overt visibility, either in the literature and studies of Chicago's ethnic landscape or through the creation of an ethnic enclave with vernacular urban centralized space distinct from other ethnic migrant groups and their neighborhoods such as Little Italy, Ukrainian Village, Greek Town and Chinatown.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"72 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70252047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mobility issues and multidimensional inequalities: exploring the limits of the National Strategy for Immigration and Asylum during the COVID-19 pandemic in Morocco","authors":"Daniela Santus, S. Ansaloni","doi":"10.3934/geosci.2023011","DOIUrl":"https://doi.org/10.3934/geosci.2023011","url":null,"abstract":"In December 2019, the severe respiratory syndrome coronavirus-2 was discovered in China. The virus spread rapidly and, by March 2020, the World Health Organization (WHO) declared COVID-19 to be a global pandemic. Scientists expected the African continent to be among the worst affected by the sanitary emergency in terms of prevalence, incidence and mortality. This prediction was refuted by evidence, considering that Africa reported the least number of cases and deaths compared to Europe, Asia and America. The first case in Africa was registered in Egypt on February 14, 2020. By the end of 2021, the continent recorded a cumulative of 7,110,817 cases and 155,505 deaths. Nonetheless, estimates are likely to be distorted due to the lack of available data about the impact of COVID-19 and the limited documentary capacity of most African countries. There are several theories to explain why, contrary to the expected trend, Africa had the fewest COVID-19 incidences compared to other continents. Africa is characterized by a young population, which is notoriously less susceptible to COVID-19, with an average age of 19.7 years. In addition, most of the Africans (59%) live in rural areas, with few opportunities to travel or get in contact with outsiders. Moreover, governments enforced outstanding measures to contain the spread of the virus and safeguard the national economy, such as strengthening their documentary capacity and enforcing effective social safety nets. However, most of these policies have aggravated entrenched patterns of discrimination, making certain populations uniquely vulnerable. Indeed, mobility restrictions and border closures severely affected people with mobile livelihoods. In Morocco, the emergency measures compromised the resilience capacity of sub-Saharan migrants, particularly women and girls. To study the phenomenon of African migration to Morocco, we conducted fieldwork research from October to December 2021, interrupted by the closure of the kingdom's borders, and continued remotely thanks to key informants.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70250509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of Hydrological Drought Index change over long period (1990–2020): The case of İskenderun Gönençay Stream, Türkiye","authors":"Serin Değerli Şimşek, Ömer Çapar, E. Turhan","doi":"10.3934/geosci.2023024","DOIUrl":"https://doi.org/10.3934/geosci.2023024","url":null,"abstract":"Recently, due to changes in the global climate, there have been significant increases in flood and drought events. The changes in wet and dry periods can be examined by various methods using hydrometeorological data to analyze climate disasters. In this study, Gönençay Stream in the Asi River Basin was chosen as the study area, which contains abundant underground and surface water reserves in Türkiye. Within this region, not only are the agricultural activities intense, but also hydraulic structure applications such as dams and reservoirs draw attention. Previous studies stated that meteorological and agricultural droughts have started to be noticed in the basin. Therefore, temporal variation analyses can positively contribute to assessing possible hydrological droughts in the following years. In this context, wet and drought periods were determined using the Streamflow Drought Index method at 3, 6, 9, and 12-month time scales with monthly average flow data observed between 1990 and 2020. At the same time, the number and probabilities of drought categories on a 12-month time scale, the first expected transition times between classifications, and the expected residence times between categories were specified. The study revealed that the most severe dry period occurred between 2013 and 2014 and was classified as Extremely Drought. The wettest period was around 2018–2019 and was classified as Extremely Wet. The largest expected time residence among all classifications was calculated for the Extremely Drought category with nine months, means that if the Extremely Drought period ever occurs, it remains for approximately nine months. While the Moderately Drought period occurred within one month following the Extremely Drought duration, and a Near Normal Wet period was observed three months after the Extremely Wet period. The most seen drought category for monthly calculations was the Near Normal Wet category, and was seen over 200 times with a 52.8% probability. Considering the Gönençay region, it is possible that any Extreme drought classification eventually regresses to normal.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"44 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70251245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The effects of climate and soil properties on the magnitude of the visual soil quality indicators: a logistic regression approach","authors":"F. Teixeira","doi":"10.3934/geosci.2023027","DOIUrl":"https://doi.org/10.3934/geosci.2023027","url":null,"abstract":"Understanding how different climates and soil properties affect the soil processes requires quantifying these effects. Visual soil quality indicators have been proposed to assess the robustness of the soil processes and infer their ability to function. The scores of the visual soil quality indicators covary with climate features and soil properties, and their magnitude is different in acid-to-neutral and alkaline soils. These variables show collinearities and interactions, and the assessment of the individual effect of each variable on the scores of the visual indicators and the selection of the best set of explanatory variables can only be made with a definite set of variables. Logistic regression was used to calculate the effects of six climate variables and four soil properties, and their interactions, on the scores of eight visual soil quality indicators. Simple models featuring climate and soil variables explained a substantial part of the variation of the visual indicators. Models were fitted for each visual indicator for acid-to-neutral and alkaline soils. The sample size needed was calculated, and the method and its validity were discussed. For two possible outcomes, the sample size using the events per variable (EPV) criterium ranges between 62 and 183 observations, while using one variable and a variance inflation factor, it ranges between 22 and 234. Except for the model of soil structure and consistency for acid-to-neutral soils, with a C statistic of 0.67, all others had acceptable to excellent discrimination. The models built are adequate, for example, for the large-scale spatial outline of the soil health indices, to couple with soil morphological-dependent pedotransfer functions, and so on. Future models should consider (test) other explanatory variables: other climate variables and indices, other soil properties and soil management practices.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70251978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rock strength degradation induced by salt precipitation: A new mechanical mechanism of sand production in ultra-deep fractured tight sandstone gas reservoirs","authors":"Dujie Zhang, Yili Kang, Lijun You, Li Xiangchen","doi":"10.3934/geosci.2023032","DOIUrl":"https://doi.org/10.3934/geosci.2023032","url":null,"abstract":"<abstract> <p>I take a typical ultra-deep tight sandstone gas reservoir located in Tarim Basin as an example to investigate the rare sand production problem. The situation of sand production was presented, and then conventional analyses were conducted. Six tight sandstone core plugs were selected to conduct rock mechanical tests before and after salt precipitation. Ultimately, a mathematical model was established to investigate the mechanism of rock strength degradation. The results of sand production prediction indicated that sand production from rock skeletons should never appear, but the rock skeletons was observed in the sand samples, and thus the impact of salt precipitation was taken into account. The experiments proved salt precipitation caused a degradation in rock strength, and the difference between actual- and predicted critical sand production pressure drop based on the weakened rock strength reduced significantly. Furthermore, the stress intensity factor on the fracture tip induced by salt precipitation reached up to 1.22 MPa·m^1/2, which was greater than the fracture toughness of tight sandstone, and it was used to explain the rock strength degradation. The results are helpful to the knowledge of the sand production problem in ultra-deep fractured tight sandstone gas reservoirs.</p> </abstract>","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135784805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digital infrastructure strategies: the case of the province of Caserta","authors":"Paolo Pane, Federico de Andreis","doi":"10.3934/geosci.2023014","DOIUrl":"https://doi.org/10.3934/geosci.2023014","url":null,"abstract":"The digital economy and the associated productivity gains generated by the diffusion of the Internet are considered fundamental components of growth models. Scientific reflection converges in considering balanced access to digital services as a diriment factor for the promotion of competitiveness, equity, economic development and social and environmental sustainability. Although the availability of infrastructure is not sufficient to achieve the full development of the territory and the community, it is nevertheless an unavoidable prerequisite for today's and future technological and digital applications and, therefore, investigating the type of association between the presence of communication networks and the socio-economic structure of the territories is essential to understanding the very nature of multidimensional inequalities and their spatial and geographical distribution, within a framework that sees infrastructure as a conversion factor and means of development for capabilities. Based on the theories of social exclusion, the capability approach and critical theory, the research presented aims to investigate, through the analysis of a case study, the possible association between the state of progress of broadband implementation and specific territorial configurations, considering also different variables of a geographical nature.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70250146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"COVID-19 and return intentions among mobile Bulgarian citizens living abroad","authors":"Vanya Ivanova","doi":"10.3934/geosci.2023020","DOIUrl":"https://doi.org/10.3934/geosci.2023020","url":null,"abstract":"The article presents the results from a virtual ethnographic study, focused on the return intentions of 11 mobile Bulgarian citizens living in several countries in the European Union and beyond, employed in highly qualified jobs. In-depth interviews were conducted online in the months of April-May 2020, at the time of the first lockdowns and restrictions on international travel both to/from Bulgaria and to multiple countries around the world. The core issues, analyzed in this article, are the motivations for potential return and how the Bulgarians abroad observe and feel the COVID-19 situation in their current destination country. The qualitative data shows that in this particular small number of respondents, the majority of the highly qualified mobile Bulgarians do not have intentions to return to Bulgaria, most of them prefer to stay in their current country. In several cases, COVID-19 blocked their opportunities to further move internationally, for example, to a new job position in a third destination country. Three figures of highly qualified mobile people are synthesized, explaining three models of return intentions at the beginning of the COVID-19 pandemic.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"1 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70251493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting European migration industries amid the Covid-19 pandemic: Changes in the recruiting practices of Bulgarian agencies","authors":"Boris Popivanov, S. Kovacheva","doi":"10.3934/geosci.2023022","DOIUrl":"https://doi.org/10.3934/geosci.2023022","url":null,"abstract":"Workforce mobility in the European Union (EU) has faced enormous challenges regarding the outbreak of Covid-19 in 2020. Member-states reacted by imposing border closures and eliciting travel restrictions and sanitary measures, some of which continued well into 2022, with far-reaching consequences in all areas of mobility experience. In a time of constant changes in the regulations of the internal market, the work of labour market intermediaries deserves special attention. Recent studies have shown that, being a relatively new EU member-state, Bulgaria managed to develop an important migration industry comprising a complex network of public and private actors. We focus on an interpretative analysis of ten in-depth interviews conducted in 2017 with practitioners working in such agencies, and ten follow-up interviews five years later. The comparative analysis of these intermediaries' reflections on the mobility policies and practices before and during the pandemic allows us to examine the processes of structural and functional adaptation in the industry in multiple dimensions: assessment of changes in mobility practices, perceptions of employers' and migrants' needs and expectations, and the challenges facing their agencies vis-à-vis the role of other actors in the field. The conclusion underlines trends and transformations which are of interest for the developing recruitment sectors in other Central and East European countries, as well as for the dynamics of the East-West labour mobility throughout the entire EU.","PeriodicalId":43999,"journal":{"name":"AIMS Geosciences","volume":"53 5 1","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70251610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}