The first essay examines the relation between fund performance and stock selection process. I classify mutual funds into two groups according to their distinctive stock selection approaches: tire kickers who rely on fund managers' personal judgment and fundamental analysis to pick stocks, and quant jocks who use computer-based models to select stocks. I examine how the stock selection approach affects mutual fund performance and economies of scale. I document an increasing trend of quantitative techniques used by mutual funds, in addition to some unique characteristics of quant jocks. Quant jocks and tire kickers have similar factor-adjusted alphas, but quant jocks have higher Sharpe ratios. Quant jocks tend to be much smaller than tire kickers. I explore possible explanations for the size difference. I find that although quant jocks can cheaply screen a large universe of stocks, the stocks that quant jocks invest in are smaller and less liquid, which results in higher transaction costs and limited scalability of quantitative investment strategies. The second essay investigates mutual fund managers' private information about future stock returns as revealed in their portfolio holdings. Specifically, we develop three different stock alpha estimators to predict stock returns based on portfolio compositions and past performance of mutual funds. We find that investment strategies based on our stock alpha estimators perform well, when using information on recent fund holdings and fund purchases. This evidence suggests that fund managers' stock selection skills are quite persistent, and vary widely in the cross-section. We also compare our strategies with 12 quantitative investment signals based on market anomalies, and find that our strategies are not subsumed by these quantitative signals. Thus, our stock alpha estimators reflect private skills of active fund managers that are unrelated to known anomalies. Finally, we develop a conditional stock alpha estimator using information on stock characteristics and fund characteristics. Investment strategies based on the conditional stock alphas deliver further improved performance.

Wakefields and the corresponding frequency-domain phenomenon beam coupling impedance have been well studied for a number of years as a source of beam instabilities within particle accelerators. With the development of the Large Hadron Collider (LHC) and the large beam currents stored in the LHC during fills for physics production, wakefield driven instabilities and strong beam induced heating have become a limiting factors in luminosity production due to both instantaneous luminousity and the available time for collisions.In this thesis is presented an in depth study of the beam coupling impedance of two important (from an impedance and operational point of view) devices in the LHC; the collimation system and the injection kicker magnets (MKIs). These systems have both been sources of concern for the beam impedance of the LHC, the collimators due to their large transverse impedance and the MKIs due to the strong heating observed during the increased of beam current during operation in 2011 and 2012. The source of the heating for the MKIs is studied in depth, found to be power lost by the beam to wakefields in the MKIs. Simulations and measurements are used to characterise the impedance and localise the areas responsible for the high impedance, here the beam screen and ferrite yoke of the magnet; improvements are proposed to better screen the ferrite yoke and verified. A new RF damping system using ferrite for the collimation system is studied and compared to the existing RF damping system, focusing on the heating of the damping system. Highlights include a new method for measuring the quadrupolar and constant transverse impedances of an asymmetric structure using a coaxial wire technique is proposed and verified using computational simulations, and a study of the heat loss in a ferrite damped cavity, focusing on the location of the power loss for cavities being damped to varying degrees.

The Super Proton Synchrotron (SPS) injection system plays a fundamental role to preserve the quality of injected high-brightness beams for the LHC physics program and to maintain the maximum storable intensity. The present set-up is the result of years of upgrades and patches of a system that was not conceived for such intensities and beam qualities. In this study, we propose the design of a completely new injection system based on multi-level numerical optimisation of the different constraints, including realistic hardware assumptions. We present the different algorithms and procedures applied in the optimisation process, and we also outline how this generic optimisation framework can be adapted to other situations for optimal accelerator system design.

Submitted by CRISTINE BASSETO CRUZ (crisbasseto@gmail.com) on 2017-03-02T23:43:51Z No. of bitstreams: 1 dissertacao 2017-02-24 final.pdf: 2091106 bytes, checksum: 2ffbc1ca866db49e442bf1009d316bf2 (MD5) / Approved for entry into archive by Renata de Souza Nascimento (renata.souza@fgv.br) on 2017-03-02T23:47:20Z (GMT) No. of bitstreams: 1 dissertacao 2017-02-24 final.pdf: 2091106 bytes, checksum: 2ffbc1ca866db49e442bf1009d316bf2 (MD5) / Made available in DSpace on 2017-03-06T12:53:39Z (GMT). No. of bitstreams: 1 dissertacao 2017-02-24 final.pdf: 2091106 bytes, checksum: 2ffbc1ca866db49e442bf1009d316bf2 (MD5) Previous issue date: 2016-12-08 / This paper intends to discuss the legal adequacy of loan arrangements among shareholders, companies offering shares in initial public offer and their underwriters pre-initial public offer. These transactions – known as 'equity kickers' – became popular during 2004 – 2007 Brazilian capital markets’ IPO wave, when several Brazilian corporations went to public offering their shares after borrowing pre-IPO money from their underwriters. Taking into account the usual arrangements among those agents and a few researches made afterwards, we examine the economic and social consequences to the issuer and to the securities market, the legal role of the underwriter under the Brazilian securities exchange legal environment and discuss the fiduciary duty imposed to financial intermediaries in capital. Further on, we discuss the potential conflict of interest arising from credit relationship between underwriters and issuing companies and the adequacy of mandatory information provided in IPO information memorandum (prospecto) for the purpose of warning potential conflict that may arise from such credit relationship. Finally, we conclude our legal analysis and suggest a review of security exchange commission (CVM) current regulation in order to address fiduciary duties to financial intermediaries and improve disclosure standards on conflict of interest to potential investors during securities public offers. / Este trabalho pretende discutir a legalidade dos arranjos contratuais e empréstimos firmados entre acionistas, companhias ofertantes e instituições intermediárias previamente à realização de ofertas públicas iniciais. Esses arranjos – conhecidos como 'equity kickers' – foram largamente utilizados por companhias brasileiras que ofertaram suas ações durante os anos de 2004 a 2007. Tendo por base o formato usualmente utilizado nessas transações e os resultados trazidos por algumas pesquisas realizadas após a realização dessas ofertas, analisamos as consequências econômicas e sociais observadas e sua pertinência para o contexto do mercado de capitais, o papel das instituições intermediárias sob a ótica da regulamentação Brasileira e seu dever fiduciário perante os demais agentes de mercado. Ademais, discutimos o potencial conflito de interesse inerente ao papel simultâneo de distribuidor e credor desempenhado pelo coordenador nessas ofertas e a comunicação desse conflito ao mercado através da divulgação das informações pertinentes no prospecto de distribuição da oferta. Por fim, apresentamos uma análise jurídica e sugerimos a revisão da regulamentação da Comissão de Valores Mobiliários no sentido de tratar expressamente o tema do dever fiduciário das instituições intermediárias no mercado de captais e aumentar a exigência de informações acerca de transparência das situações de conflito ao mercado na realização de ofertas públicas de valores mobiliários.

The Compact Linear Collider (CLIC) is a proposal for a future linear electron--positron collider that could achieve collision energies of up to 3 TeV. In the CLIC concept the main high energy beam is accelerated using RF power extracted from a high intensity drive beam, achieving an accelerating gradient of 100 MV/m. This scheme places strict tolerances on the drive beam phase stability, which must be better than 0.2 degrees at 12 GHz. To achieve the required phase stability CLIC proposes a high bandwidth (>17.5 MHz), low latency drive beam "phase feedforward" (PFF) system. In this system electromagnetic kickers, powered by 500 kW amplifiers, are installed in a chicane and used to correct the phase by deflecting the beam on to longer or shorter trajectories. A prototype PFF system has been installed at the CLIC Test Facility, CTF3; the design, operation and commissioning of which is the focus of this work. Two kickers have been installed in the pre-existing chicane in the TL2 transfer line at CTF3 for the prototype. New optics have been created for the line to take these changes in to account, incorporating new constraints to obtain the desired phase shifting behaviour. Three new phase monitors have also been installed, one for the PFF input and two to verify the system performance. The resolution of these monitors must be significantly better than 0.2 degrees to achieve CLIC-level phase stability. A point by point resolution as low as 0.13 degrees has been achieved after a series of measurements and improvements to the phase monitor electronics. The performance of the PFF system depends on the correlation between the beam phase as measured at the input to the PFF system, and the downstream phase, measured after the correction chicane. Preliminary measurements found only 40% correlation. The source of the low correlation was determined to be energy dependent phase jitter, which has been mitigated after extensive efforts to measure, model and adjust the machine optics. A final correlation of 93% was achieved, improving the theoretical reduction in jitter using the PFF system from a factor 1.1 to a factor 2.7. The performance and commissioning of the kicker amplifiers and PFF controller are also discussed. Beam based measurements are used to determine the optimal correction timing. With a maximum output of around 650 V the amplifiers provide a correction range of ±5.5 ± 0.3 degrees. Finally, results from operation of the complete system are presented. A mean phase jitter of 0.28 ± 0.02 degrees is achieved, in agreement with the theoretical prediction of 0.27 ± 0.02 degrees for an optimal system with the given beam conditions. The current limitations of the PFF system, and possible future improvements to the setup, are also discussed.