On the spectrum of the twisted Dolbeault Laplacian over K\"ahler manifolds

We use Dirac operator techniques to a establish sharp lower bound for the first eigenvalue of the Dolbeault Laplacian twisted by Hermitian-Einstein connections on vector bundles of negative degree over compact K\"ahler manifolds.Comment: 14 pages. Completely revised: estimates corrected and shown to be shar

Equilibrium, Adverse Selection, and Statistical Distributions

This paper addresses the problem of multiple equilibria in markets with adverse selection. Akerlof (1970) identified an unique equilibrium of the total market failure under adverse selection. Posterioly, Wilson (1979, 1980) argued that the presence of adverse selection may lead to multiple equilibria. In particular, this paper extends the work of Rose (1993), who stated that the existence of multiple equilibria depends on the distribution of quality. Rose found that multiple equilibria are highly unlikely for most standard probability distributions. This work considers additional statistical distributions for quality. The simulation results suggest the existence of multiple equilibria when the quality follows a beta normal distribution.Adverse Selection; Multiple Equilibria; Statistical Distributions; Akerlof-Wilson Model.

New Network Goods

New horizontally-differentiated goods involving product-specific network effects are quite prevalent. Consumers market-wide preference for each of these goods typically is initially unknown. Later, as sales data begin to accumulate, agents learn market-wide preferences, which thus become common knowledge. We study such a market, pinpointing the factors which determine whether the market-wide preferred firm reinforces its lead as time elapses, penetration and under-cost pricing prevail, and first- or last-mover effects in market-wide preferences occur.Network effects, horizontal differentiation

"Can Portugal Escape Stagnation without Opting Out from the Eurozone?"

The creation of the Economic and Monetary Union (EMU) has not brought significant gains to the Portuguese economy in terms of real convergence with wealthier eurozone countries. We analyze the causes of the underperformance of the Portuguese economy in the last decade, discuss its growth prospects within the EMU, and make two proposals for urgent institutional reform of the EMU. We argue that, under the prevailing institutional framework, Portugal faces a long period of stagnation, high unemployment, and painful structural reform, and conclude that, in the absence of institutional reform of the EMU, getting out of the eurozone represents a serious political option for Portugal.Nominal Wage Cuts; Eurozone; Relative Unit Labor Costs; Zero-sum Game

Interruptions and failure in higher education: evidence from ISEG-UTL

Abstract Failure in Higher Education (HE) is the outcome of multiple time-dependent determinants. Interruptions in student’s individual school trajectories are one of them and that’s why research on this topic has been attracting much attention these days. From an individual point of view, it is expected that interruptions in school trajectory, whatever the reason, influence success in undergraduate programs either this success is measured by time required to obtain a degree, the scores obtained in some more “critical” subjects in these programs or the number of enrolment registrations. Nevertheless, performing a paid job during interruption may in given circumstances positively affect academic success on account of the combination between learning and occupational experience The study of interruptions’ impact on failure in HE is also important to help Education institutions at all grades to think about changes in organisational procedures, class timetables, syllabuses contents or teachers recruitment and training in order to fight this problem. From a social and political point of view, interruptions are also a matter of concern since failure in HE affects individual’s lifelong learning opportunities, distort public funding allocation efficiency to HE institutions and create lag effects in the desired/planned outcomes of HE production functions. So, research on the impact of interruptions on failure in HE is important to support policy measures definition related to the articulation between Upper Secondary and HE programs. In previous research we have shed some light into the determinants of failure in 1st year of HE studies using longitudinal data on ISEG’s undergraduate students. A further insight into this database revealed the existence of a meaningful number of students with interruptions in their school trajectories either in the transition from Upper Secondary to HE or within HE programs. In this paper our major concern is to find some evidence on interruptions effects on HE failure among ISEG students using a life cycle approach with control group. We are interested in knowing whether the above mentioned effects are gender and/or specific graduation program neutral. We also want to search if work experience may counter balance the effect of interruption on academic success. We hope to be able to derive some useful recommendations to address policy making in the fields of pedagogic methodologies in HE, articulation between academic and occupational learning in the framework of Bologna Chart and public funding/fellowship policies in HE.Key words: Portuguese Higher Education; Interruption; Failure; Adult Students; Bologna Chart; Policy Implications

Integration of green hydrogen in the European energy systems

Hydrogen has been suggested as a way to decarbonise the global energy system for decades but has yet to have a breakthrough on the European energy market. For the past decade, the efforts to reduce carbon emissions in the European energy market have increased, leading to rapid changes and a decline in costs of renewable energy. These efforts to reduce carbon emissions, combined with difficulties of decarbonising in several sectors due to few viable alternatives, surged the interest in hydrogen as a possible solution. This thesis investigates how large scale production of hydrogen via electrolysers can be integrated into a future power system with high shares of renewable energy capacity. Based on a literature review, a scenario for the year 2050 was constructed with the aim to identify sectors with potential hydrogen demand in the future. The scenario focuses on Germany and the United Kingdom and was implemented in a power market dispatch model called Bid3 to analyse its effects on the European energy system. The hydrogen demand was estimated to 225 TWh for Germany and 157 TWh for the United Kingdom whereas the necessary storage capacity for the two countries was identified to between 20 to 24 TWh. The sectors with the largest hydrogen potential were identified as the residential and commercial heating sector as well as the heavy vehicle transportation sector. Moreover, the implementation of hydrogen managed to reduce greenhouse gas emissions by 88.8 M tonnes CO2-eq per year. The implemented electrolysers showed great synergy with renewable energy capacity by improving the flexibility of the power system. As a result, it also reduced the severity of price crashes due to oversupply of renewable energy generation. However, even with installed electrolysers, the high share of renewable energy capacity caused several hours of wholesale power price close to zero. Hence, the scenario highlighted the difficulties of obtaining a power system with a high share of renewable capacity within the regulations of the current power market.Den europeiska energimarknaden ändras snabbt till följd av sjunkande kostnader för förnybar energi och politisk vilja att reducera växthusutsläpp. Detta tillsammans med svårigheter att byta ut kolbaserade produkter inom en del sektorer har lett till ett ökat intresse för vätgas som en potentiell del av lösningen. Denna uppsats analyserar hur storskalig vätgasproduktion med elektrolys kan integreras i ett framtida elsystem med stor andel förnybar energi. Ett scenario för 2050 utformades för att identifiera den potentiella efterfrågan av vätgas i flera sektorer. Scenariot fokuserade på Tyskland och Storbritannien vilket implementerades i elsystemsmodellen Bid3 för att analysera effekterna på energisystemen i Europa. Efterfrågan på vätgas uppskattades till 225 TWh för Tyskland och 157 TWh för Storbritannien, vilket täcktes av nationell produktion via elektrolys och de sektorer med störst uppskattad efterfrågan identifierades som värmesektorn samt transportsektorn. Genom produktion av vätgas som ersatte kolbaserade bränslen och produkter, kunde utsläppen reduceras med 88.8 M ton CO2-ekv per år. Vätgasproduktion med elektrolys i förbindelse till elnätet ökade också flexibiliteten i elsystemet. Detta ledde till större motstånd vid prisras som kan uppstå vid överproduktion av förnybar energi. Dock ledde det konstruerade scenariot trots vätgasproduktion till ett stort antal timmar med låga elpriser, vilket visar på svårigheter i att integrera stora mängder förnybar energi i den nuvarande elmarknaden

Singing a(n) "(a)laukika" body : a note on the theorization of "utprekṣā" and Its application in the Pāṇḍyakulodayamahākāvya"

Utprekṣā or ‘ascription’ is one of the foremost devices in classical Sanskrit literature, with importance secondary only to upamā and rūpaka. In contrast to other figures extensively analysed by the theoretical treatises over centuries, it was characterised by a surprising uniformity in regard to its definition as offered by the ālaṃkārikas. The paper provides a brief overview of this device and its practical application in a 16th century mahākāvya, the Pāṇḍyakulodaya

The Evolution Of Agricultural Land Use Patterns In The State Of Bahia, Brazil

This dissertation deals with the historical spatial analysis of agriculture of Bahia, the earliest economic core of Brazil. Emphasis is on the economic processes responsible for the expansion and location of agriculture from colonization in 1549 until 1970. The conceptual framework is von Thunen\u27s classic model of agricultural location, which was chosen because it contains predictions (under equilibrium and dynamic conditions) related to both the evolution and location of agriculture.;Comparison between Bahia\u27s agricultural reality and theoretical conditions of The Isolated State employs the method of comparative statics, whereby the time is divided into four stages, each one in succession treated as an equilibrium solution for its respective time period.;(1) Origins (1500-1570), includes the discovery of Brazil and the application by Portugal of mercantilistic policies which resulted in Bahia\u27s colonization. Von Thunen\u27s prediction that intensity of agriculture is inversely related to distance from a market is observed in Bahia. (2) Gradual Expansion (1571-1822), includes the remainder of colonial times and ends with the political independence of Brazil. Continued expansion of sugar plantations fails to confirm von Thunen\u27s prediction that a fall in prices of agricultural products leads to a spatial contraction of agricultural land use regions. The relationship between the intensity of agriculture and distance from the major market of Salvador, however, remains consistent. (3) Rapid Expansion (1823-1930), includes the post-colonial period to the beginning of the Depression. Von Thunen\u27s predictions that increase in demand and transportation improvements cause expansion of agriculture are both empirically observed in Bahia. This results in the evolution of the two earlier agricultural zones into three based on the impact of the industrial revolution. (4) Spatial Adjustment (1931-1970), begins with the Depression which led to major changes in Brazil, including government policies to promote sectorial industrialization, and culminates with the last agricultural census. Von Thunen\u27s prediction that lower demand for agricultural products causes contraction of agricultural space and an increase in extensive types of agriculture is partially verified. A clear trend for agricultural land uses to be located according to their respective markets is also observed. . . . (Author\u27s abstract exceeds stipulated maximum length. Discontinued here with permission of school.) UM