Suchergebnisse

Climate change poses increasing risks to food security of South Asia with more severe heat stress, water scarcity, and flooding. As one of the major adaptation measures, adjusting crop calendars could be a feasible and effective solution to avoid adverse effects on crop yield potentials in a changing climate by allowing crops to grow in more favorable weather conditions. Previous single-crop and single-objective studies on the optimization of crop planting dates lack comprehensive consideration of multi-crop rotation systems, especially rice-based cropping systems with very short growing season intervals in Asian tropical monsoon regions. This study seeks to better understand potentials and limitations of adjusting crop calendars for climate change adaptation of double-rice and rice-wheat rotation systems, with a particular focus on the following questions: (1) Is it possible to avoid yield loss of rice and wheat through adjusting crop calendars in the study area? (2) How will fallow period between crop growing seasons change in the future? (3) What are relationships between crop yield improvement, irrigation water requirement, and heat stress mitigationin the study area? To address these questions, we calibrated a spatial implementation of the Environmental Policy Integrated Climate (EPIC) agronomic model to estimate annual potential yields, irrigation water requirement, and heat stress days of irrigated double-rice and rice-wheat cropping systems in Bangladesh, India, and Myanmar (the BIM countries), and adjusted crop calendars (a) by single-objectiveoptimization with maximum yield and (b) multi-objective optimization with least irrigation water requirement, minimum heat stress days, and highest potential yield under climate change. Our results indicate that most yield loss in rice and wheat could be avoided through shifting planting dates while considering effects of elevated atmospheric CO2concentration on biomass assimilation and transpiration. The model indicates that fallow periods between kharif-rice harvest dates and rabi-rice planting dates in double-rice systems are likely to become longer due to shorter growing season duration meanwhile fallow periods between kharif-rice harvest dates and rabi-wheat planting dates in rice-wheat systems are likely to become shorter due to advanced planting dates of rabi wheat, which implies that double-rice systems in the BIM countries will have more flexibility to cope with smaller time windows for crop growth and development in the future. Moreover, nearly half of the study area hasthe potential to increase yield by more than 10% through changing crop calendars compared to the basic scenario with non-adjusted crop calendars under RCP8.5 in 2080s, but 59% of these areas would face contradictions in obtaining crop yield improvement, saving irrigation water, and mitigating heat stress in the future. We found those areas suitable foradoptingshifting planting dates as one of adaptation strategiesfrom the perspective of climate conditions, such as Punjab state in India and Rangpur in Bangladesh, are also the areas with shortened growing season intervals, which requires great efforts to achieve the adaptation objectives under climate change. Thus, the trade-off among economic cost, environmental impacts, and food security should be carefully considered for local governments and farmers to promote adjustment of crop calendars in the future.

Climate change poses increasing risks to food security of South Asia with more severe heat stress, water scarcity, and flooding. As one of the major adaptation measures, adjusting crop calendars could be a feasible and effective solution to avoid adverse effects on crop yield potentials in a changing climate by allowing crops to grow in more favorable weather conditions. Previous single-crop and single-objective studies on the optimization of crop planting dates lack comprehensive consideration of multi-crop rotation systems, especially rice-based cropping systems with very short growing season intervals in Asian tropical monsoon regions. This study seeks to better understand potentials and limitations of adjusting crop calendars for climate change adaptation of double-rice and rice-wheat rotation systems, with a particular focus on the following questions: (1) Is it possible to avoid yield loss of rice and wheat through adjusting crop calendars in the study area? (2) How will fallow period between crop growing seasons change in the future? (3) What are relationships between crop yield improvement, irrigation water requirement, and heat stress mitigationin the study area? To address these questions, we calibrated a spatial implementation of the Environmental Policy Integrated Climate (EPIC) agronomic model to estimate annual potential yields, irrigation water requirement, and heat stress days of irrigated double-rice and rice-wheat cropping systems in Bangladesh, India, and Myanmar (the BIM countries), and adjusted crop calendars (a) by single-objectiveoptimization with maximum yield and (b) multi-objective optimization with least irrigation water requirement, minimum heat stress days, and highest potential yield under climate change. Our results indicate that most yield loss in rice and wheat could be avoided through shifting planting dates while considering effects of elevated atmospheric CO2concentration on biomass assimilation and transpiration. The model indicates that fallow periods between kharif-rice harvest dates and rabi-rice planting dates in double-rice systems are likely to become longer due to shorter growing season duration meanwhile fallow periods between kharif-rice harvest dates and rabi-wheat planting dates in rice-wheat systems are likely to become shorter due to advanced planting dates of rabi wheat, which implies that double-rice systems in the BIM countries will have more flexibility to cope with smaller time windows for crop growth and development in the future. Moreover, nearly half of the study area hasthe potential to increase yield by more than 10% through changing crop calendars compared to the basic scenario with non-adjusted crop calendars under RCP8.5 in 2080s, but 59% of these areas would face contradictions in obtaining crop yield improvement, saving irrigation water, and mitigating heat stress in the future. We found those areas suitable foradoptingshifting planting dates as one of adaptation strategiesfrom the perspective of climate conditions, such as Punjab state in India and Rangpur in Bangladesh, are also the areas with shortened growing season intervals, which requires great efforts to achieve the adaptation objectives under climate change. Thus, the trade-off among economic cost, environmental impacts, and food security should be carefully considered for local governments and farmers to promote adjustment of crop calendars in the future.

Based on 15 months of ethnographic field work in a small factory in southeast China, this thesis is about a new population and a new media. Described as the biggest migration in human history, an estimated 250 million Chinese peasants have left their villages to live and work in urban areas. The vast Chinese rural migrant population that did not exist three decades ago is taking on its new form alongside the rise of social media in contemporary China which itself did not exist two decades ago. The ethnography included intense interaction with a broad range of factory workers both online and offline. One of the most significant findings is the way in which this population challenges the full range of preconceptions commonly held about Chinese people – their relationship with family, with education, with politics, with religion and with 'home'. The thesis argues that a population of 250 million cannot be regarded as a mere exception and should assume a central role in our understanding of contemporary Chinese people. As well as social media providing a route for the ethnography of this population, the study is equally addressing claims and generalisations made about social media itself, and its use and consequences. In many respects it was online sociality that had become central to these people's lives, rather than the direct relationship to fellow workers. So the overarching argument of this thesis is alongside the rural to urban migration, there is a second migration taking place: a movement from offline to online. The 'dual migration' is not simply a convenient analogy but represents the convergence of two phenomena as profound and consequential as each other, where the online world now provides a home for the migrant workers who feel otherwise 'homeless'.

Abstract. Polarization is a new phenomenon that threatens the cohesion and social development of our society. The raise of social media is known to have contributed significantly to the emergence of this phenomenon as it can be noticed from the multiplication of far right and racist online communities as well as the ill-structured political discourse. This can be noticed from scrutinizing recent US or EU elections. Automatic identification of polarization from social media plays a key role in devising appropriate defence strategy to tackle the issue and avoid escalation. This thesis implements several methods to identify polarization from Twitter data issued from Trump-Clinton US election campaign using metrics like Belief Polarization Index (BPI) and Sentiment Analysis. Furtherly, semantic role labelling and argument mining were applied to derive structure of arguments of polarized discourse. Especially, we constructed thirteen topics of interests that were used as potential candidates for polarized discourse. For each topic, the cosine distance of the frequency of the topic overtime between the two candidates was used to indicate the polarization (called as Belief Polarization Index). The statistics inference of sentiment scores was implemented to convey either a positive or negative polarity, which are then further examined using argument structure. All the proposed approaches provide attempts to measure the polarization between two individuals from different perspectives, which may give some hints or references for future research.Tiivistelmä. Polarisaatio on uusi ilmiö, joka uhkaa yhteiskuntamme yhteenkuuluvuutta ja sosiaalista kehitystä. Sosiaalisen median nousun tiedetään vaikuttaneen merkittävästi tämän ilmiön syntymiseen, koska se voidaan havaita äärioikeistolaisten ja rasististen verkkoyhteisöjen lisääntymisestä sekä huonosti jäsennellystä poliittisesta keskustelusta. Tämä voidaan havaita tarkastelemalla äskettäisiä Yhdysvaltojen tai EU: n vaaleja. Polarisaation automaattisella tunnistamisella sosiaalisesta mediasta on keskeinen rooli sopivan puolustusstrategian suunnittelussa ongelman ratkaisemiseksi ja eskalaation välttämiseksi. Tässä opinnäytetyössä toteutetaan useita menetelmiä polarisaation tunnistamiseksi Yhdysvaltain Trump-Clintonin vaalikampanjan Twitter-tiedoista käyttämällä mittareita, kuten vakaumuspolarisaatio indeksi (BPI) ja mielipiteiden analyysi. Lisäksi semanttisen roolin merkintöjä ja argumenttien louhintaa sovellettiin polarisoidun diskurssin argumenttien rakenteen johtamiseen. Erityisesti rakensimme kolmetoista aihepiiriä, joita käytettiin potentiaalisina ehdokkaina polarisoituneeseen keskusteluun. Kunkin aiheen kohdalla kahden ehdokkaan aiheiden ylityötiheyden kosinietäisyyttä käytettiin osoittamaan polarisaatiota (kutsutaan nimellä Belief Polarization Index). Tunnelmapisteiden tilastollinen päättely toteutettiin joko positiivisen tai negatiivisen napaisuuden välittämiseksi, joita sitten tutkitaan edelleen argumenttirakennetta käyttäen. Kaikki ehdotetut lähestymistavat tarjoavat yrityksiä mitata kahden ihmisen välistä polarisaatiota eri näkökulmista, mikä saattaa antaa vihjeitä tai viitteitä tulevaa tutkimusta varten.

It is well established in vertical product differentiation models that the high–quality firm reaps a larger profit in a two–stage quality–price game as long as the cost of quality improvement is zero or is borne as fixed cost in the first stage quality choice. This note shows that the high–quality advantage may fail to hold if there is variable cost of production that is dependent on quality.

The Eurozone Debt Crisis has rekindled the debate on the nexus between currency areas and fiscal sovereigns. After the crisis, much of the intellectual and political debate has been on the benefit of a fiscal union, the idea of creating a common fiscal entity that is well equipped to make state-contingent cross-country transfers within the eurozone. Although the role of a benevolent fiscal union can in theory be welfare-improving for a currency union, it is understood that this is a highly politically constrained option, particularly in the Eurozone. Given this constraint, in this paper, we take the implausibility of fiscal union as given, and argue that debt restructuring can be a close substitute to a fiscal union, leading to welfare improvement. In contrast to a fiscal union that resorts to the government's visible hand to move nominal resources across countries, the debt restructuring plan designs the bankruptcy rules, but it allows the invisible hand of the markets to make the choice based on context-dependent incentives. Much of the insight in this paper originates from Goodhart, Peiris and Tsomocos (2018) and Wang (2019). The authors show that debt restructuring is particularly vital in currency unions and can lead to significant welfare improvement for both the debtor and the creditor, given a hard government budget constraint. A wider implication of this paper is that for the understanding of modern monetary and financial phenomena, particularly the viability of a currency union, we simply cannot ignore the interplay of liquidity and default.

In the past decade, collaborations between China and the European Union (EU) have been rapidly expanding. Hitherto, however, little research has been carried out to assess the implementation and impacts of such collaborations. This article presents an in- depth analysis of the scientific collaborations between China and the EU28, focusing on the major research priorities and benefits of these collaborations. To shed light on the initiatives of collaborations, corresponding authors are detected and classified into three categories: Chinese local, Chinese abroad, and non-Chinese. Evidence shows that academic collaborations between China and the EU28 have been mainly set up by Chinese researchers. In the fast- growing China- EU collaborative fields, the revealed comparative advantage scores in China have improved substantially. In the EU28, however, there is no such obvious improvement.