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Coming dissertations at Uppsala university

  • Electoral Incentives and Information Content in Macroeconomic Forecasts Author: André Reslow Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-433165 Publication date: 2021-02-24 10:35

    Essay I (with Davide Cipullo): This essay introduces macroeconomic forecasters as new political agents and suggests that they use their forecasts to influence voting outcomes. The essay develops a probabilistic voting model in which voters do not have complete information about the future economy and rely on professional forecasters when forming beliefs. The model predicts that optimal forecasters with economic interests (stakes) and influence publish biased forecasts before a referendum. The theory is tested using data surrounding the Brexit referendum. The results show that forecasters with stakes and influence released more pessimistic and incorrect estimates for GDP growth subject to the leave outcome than other forecasters.

    Essay II (with Davide Cipullo): This essay documents the existence of Political Forecast Cycles. A theoretical model of political selection shows that governments release overly optimistic GDP growth forecasts ahead of elections to increase the reelection probability. The theory is tested using forecast data from the United States, the United Kingdom, and Sweden. The results confirm key model predictions and show that governments overestimate short-term GDP growth by 10 to 13 percent during campaign periods. Moreover, the bias is larger when the incumbent is not term-limited or constrained by a parliament led by the opposition. Furthermore, election timing determines the size of the bias at different forecast horizons.

    Essay III: This essay assesses to what extent forecasters use competitors’ forecasts efficiently. Empirical results using a large panel of forecasters suggest that forecasters underuse information from their competitors when forecasting GDP growth and inflation. The results also show that forecasters pay more attention to competitors when releasing short-term forecasts than medium-term forecasts. A belief updating model with noisy and private information supports the underuse interpretation and predicts that it is optimal to pay sizable attention to competitors’ work. Furthermore, the essay shows that a revision cost model can only match the observed behavior if asymmetric horizon discounting between cost from revisions and loss from forecast errors is assumed.

    Essay IV (with Michael K. Andersson and Ted Aranki): This essay proposes a method to account for differences in release dates when assessing an unbalanced panel of forecasters. Cross-institutional forecast evaluations may be severely distorted because forecasts are made at different points in time and thus with different amounts of information. The proposed method computes the timing effect and the forecaster’s ability (performance) simultaneously. Simulations demonstrate that evaluations that do not adjust for the differences in information may be misleading. The method is also applied to a real-world data set of 10 Swedish forecasters, and the results show that the forecasters’ ability ranking is affected by the proposed adjustment.

  • The Monoamine Oxidase A Gene and Antisocial Outcomes : An Examination of Genetic, Epigenetic, and Environmental Factors Author: David Checknita Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-433657 Publication date: 2021-02-23 10:04

    Background. Antisocial behaviour involves violation of the basic rights of others or social norms or rules. Such behaviours are indexed in diagnoses such as conduct disorder (CD) in adolescence and antisocial personality disorder (ASPD) in adulthood, which are typified by comorbidity with mood, anxiety, and substance misuse disorders. Alcohol misuse is strongly associated with antisocial behaviour and persistent aggressive behaviours. How environmental and biological factors interface to modulate risk for these outcomes is not yet understood, however, the interaction of adversity with a variable number tandem repeat (uVNTR) polymorphism of the monoamine oxidase gene A (MAOA) gene associates with antisocial behaviour and mental disorders. Further, DNA methylation in a region of interest (ROI) spanning MAOA’s first exonic/intronic junction associates with ASPD in men as well as other mood, anxiety, and substance misuse disorders. 

    Aim and Methods. We characterized methylation of the MAOA ROI by sex and age and examined how negative and positive environmental factors interact with MAOA genotype and methylation on antisocial phenotypes and mental disorders. Participants included men and women from a clinical population of young adults recruited in adolescence at a substance misuse clinic and a community sample of adolescents. 

    Findings. (1) Sex but not age was associated with methylation levels such that high methylation levels among women likely represent X-chromosome inactivation, and sexual abuse was associated with hypermethylation of the MAOA first exon, (2) high methylation levels mediated associations between sexual abuse and current depression diagnosis in women, (3) the highest levels of aggressive behaviour were found among maltreat male carriers of the low-expressing MAOA-uVNTR allele and displayed high levels of exonic methylation, while no interactions were shown in women, and (4) among adolescent girls, but not boys, positive parent-child relationship attenuated the interaction of maltreatment and the high-expressing MAOA-uVNTR allele on alcohol consumption, though the interactions were not robust to adjustments for tobacco use, substance misuse, and delinquent behaviours.

    Conclusion. The findings presented here advance our understanding of how maltreatment interfaces with genotypic and epigenetic factors, in a sex-dependent manner, to promote aggressive behaviour and mental disorders among susceptible individuals.

     

  • Ultra-wideband Millimeter-wave Antenna Arrays and Front-end Systems : For high data rate 5G and high energy physics applications Author: Imran Aziz Link: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-433095 Publication date: 2021-02-22 09:58

    The demand for wireless data communications is rapidly increasing due to several factors including increased internet access, increasingly growing number of mobile users and services, implementation of the Internet of Things (IoT), high-definition (HD) video streaming and video calling. To meet the bandwidth requirement of new and emerging applications, it is necessary to move from the existing microwave bands towards millimeter-wave bands. 

    This thesis presents different antenna arrays at 60 GHz and 28 GHz that are integrated with the front-end RFIC to steer the beam in ≈ ±50° in the azimuth plane. The 5G antenna arrays at 28 GHz are designed to provide broadband high data rate services to the end users. In order to transport this high-volume data to the core network, a fixed wireless access (FWA) link demands the implementation of a broadband, high gain and steerable narrow-beam array. The 60 GHz antenna arrays, presented in this thesis, are good candidates for both FWA as well as backhaul communications. The two proposed arrays at 60 GHz (57-66 GHz) are i) a stacked patches array and ii) a connected slots array feeding a high gain lens antenna. The 2×16 stacked patches antenna array shows more than 20 dBi realized gain. The array is integrated with the front-end RFIC and the resulting module shows > 40 dBm measured effective isotropic radiated power (EIRP). The other 60 GHz antenna array is designed as linear connected slots with sixteen equidistant feeding points. The latest is then used as a feeder of a high gain dielectric lens. Peak measured gain of 25.4 dBi is achieved with this antenna.  Moreover, instead of experiencing scan loss, the lens is designed to get higher gain when the beam is steered away from the broadside direction.

    Furthermore, two compact antenna arrays are designed at 28 GHz (24.25 - 29.50 GHz). A linear polarized (LP) and a circular polarized (CP) array are realized in the fan-out embedded wafer level ball-grid-array (eWLB) package. In comparison with the PCB arrays, this antenna in package (AiP) solution is not only cost-effective but it also reduces the integration losses because of shorter feed lines and no geometrical discontinuity.  The LP array is realized as a dipole antenna array feeding a novel horn-shaped heatsink.  The RF module gives 34 dBm peak EIRP with beam-steering in ±35°. Besides, the CP antenna array is realized with the help of crossed dipoles and the RF module provides 31 dBm peak EIRP with beam-steering in ±50°.

    The data demands are not limited to the telecom industry as the upgradation of accelerators and experiments at the large hadron collider (LHC) at CERN will result in increased event rate thus demanding higher data rate front-end readout systems. This work thus investigates the feasibility of 60 GHz wireless links for the data readout at CERN. For this purpose, the 60 GHz wireless chips are irradiated with 17 MeV protons [dose 7.4 Mrad (RX) & 4.2 Mrad (TX)] and 200 MeV electrons [dose 270 Mrad (RX) & 314 Mrad (TX)] in different episodes. The chips have been found operational in the post-irradiation investigations with some performance degradation. The encouraging results motivate to move forward and investigate the realization of wireless links in such a complex environment.

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