<p>Modern massive data, with enormous sample size and tremendous dimensionality, are usually stored and processed using a cluster of nodes in a master-worker architecture. A shortcoming of this architecture is that inter-node communication can be over a thousand times slower than intra-node computation, which makes communication efficiency a desirable feature when developing distributed learning algorithms. In this dissertation, we tackle this challenge and propose communication-efficient bootstrap methods for simultaneous inference in the distributed computational framework.</p> <p>  </p> <p>First, we propose two generic distributed bootstrap methods, \texttt{k-grad} and \texttt{n+k-1-grad}, which apply multiplier bootstrap at the master node on the gradients communicated across nodes. Based on them, we develop a communication-efficient method of producing an $\ell_\infty$-norm confidence region using distributed data with dimensionality not exceeding the local sample size. Our theory establishes the communication efficiency by providing a lower bound on the number of communication rounds $\tau_{\min}$ that warrants the statistical accuracy and efficiency and showing that $\tau_{\min}$ only increases logarithmically with the number of workers and the dimensionality. Our simulation studies validate our theory.</p> <p>  </p> <p>Then, we extend \texttt{k-grad} and \texttt{n+k-1-grad} to the high-dimensional regime and propose a distributed bootstrap method for simultaneous inference on high-dimensional distributed data. The method produces an $\ell_\infty$-norm confidence region based on a communication-efficient de-biased lasso, and we propose an efficient cross-validation approach to tune the method at every iteration. We theoretically prove a lower bound on the number of communication rounds $\tau_{\min}$ that warrants the statistical accuracy and efficiency. Furthermore, $\tau_{\min}$ only increases logarithmically with the number of workers and the intrinsic dimensionality, while nearly invariant to the nominal dimensionality. We test our theory by extensive simulation studies and a variable screening task on a semi-synthetic dataset based on the US Airline On-Time Performance dataset.</p>

Newts of the genus Taricha have long been studied due to the powerful neurotoxin found in their skin. Tetrodotoxin (TTX) acts by blocking receptors in sodium channels, ultimately resulting in death via asphyxiation. The only documented predators of species in this genus have been snakes of the genus Thamnophis. Recently, predation on Taricha in Ledson Marsh in Annadel State Park, Santa Rosa, CA was discovered. Predation was in the form of laceration or evisceration, and tracking of predation from 1998-2008 showed that it was male-biased. Two species of Taricha were found living sympatrically at this location, the California newt (T. torosa) and the rough-skinned newt (T. granulosa). Fluorometric High Phase Liquid Chromatography (HPLC) analysis was used in order to quantify TTX levels in the skin of ten male and ten female newts of each species. Quantification of TTX was done to determine the influence, if any, that TTX levels may have on sex-biased predation in this population. I predicted that levels of TTX would be greater in females than males, and greater in T. granulosa than T. torosa since very few T. granulosa were preyed upon during the study period. My results indicated that there were significant differences between the sexes, and T. torosa were significantly more toxic than T. granulosa. An in-depth ecological study of relative abundances of both species and identification of the predator are needed at this site to obtain a clear picture of the predator-prey dynamics at Ledson Marsh

On previous occasions in society when the labor market has changed due to new technology, there has been concern that people would lose their jobs. Over the past year, the development of various AI tools has emerged, which has affected people both in their personal lives and professional careers. By examining previous research in conjunction with interviewing individuals working as programmers, a depiction is presented of how the perception of AI looks within the specific professional role. Six semi-structured interviews were conducted, where individuals with different experiences and roles shared their perceptions of the development. The data from the interviews was analyzed and compared with the theory and previous research presented. The respondents' overall perception is positive, and they believed that AI would rather serve as an aid in their profession in the future. According to all respondents, the industry will undergo some changes, but primarily through streamlining and reducing manual work, rather than taking over their roles. Some of the respondents believed that AI could pose a threat to the programming profession, but it will take longer than ten years for that to happen.

Labor intensive sectors such as the specialty crop sector have historically had strong reliance on foreign labor, constituting roughly oneifth of all U.S. farms while incurring roughly two-thirds of direct-hire expenses. It is estimated that more than half unauthorized of the foreign-born labor force in the specialty crop sector are unauthorized for US employment. Using data from the National Agricultural Workers Survey for 1989-2014, this study uses a treatment effects approach (via propensity score matching and minimum-biased estimation) to evaluate the farm wage implications of legalization of foreign-born specialty crop farm workers nationally, as well as specifically in California. Positive wage effects are estimated in nationally and in California, with higher magnitude effects observed in California.

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Title: “The influence of managers personal preferences on sport sponsorship in small-medium sized businesses - A qualitative case study of the effect on brand equity” Date: 2023-05-23Level: Bachelor Thesis in International MarketingAuthors: Emma Salqvist &amp; Hanna Hedin Supervisor: Olga Rauhut Kompaniets Examiner: Fawzi Halila Aim: This study aims to provide an analysis of how the managers’ personal preferences on sport sponsorship has an impact on the sponsoring company’s brand equity in small-medium sized companies. Methodology: The study has a qualitative research method with a deductive approach. A conceptual model was made based on a theoretical framework of findings from previous studies. Three main themes were highlighted, including brand equity, sport sponsorships in brand strategy and managerial aspects of sport sponsorship. Empirical material was collected through six semi-structured interviews with managers in a decision making role within sport sponsorship decisions. Further the results were thematically analyzed. Findings: In small-medium sized companies, sport sponsorship is often driven by managers’ personal objectives which conflicts with brand strategy. When personal objectives dominate the sponsorship decisions, the effect on brand equity tends to be limited in comparison to strategic decisions. Keywords – Sport Sponsorship, Brand Strategy, Brand Equity, Managers’ roll, Biased Decisions, Sponsorship Objectives Paper type – Bachelor thesis

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Sexual dimorphism, i.e., differences in morphology, physiology, and behavior between conspecific males and females, is ubiquitous, extensive, and often species-specific, indicative of its rapidly evolving nature. Ever since Darwin first described a general theory of sexual selection to explain the extraordinary differences between males and females of the same species, biologists have proposed a variety of mechanisms ranging from runaway selection to good genes to sexual conflict. While a popular approach is studying the effects of sexual selection on different components of fitness, the results of these studies are generally difficult to interpret and are typically not generalizable across populations, let alone taxa. Recent advances in the “omics” field are transforming the way that we study patterns and processes involved in sexual selection. At the molecular level, sexual dimorphism is present in gene expression differences between the sexes, providing a powerful framework to study sexual selection. By studying genes that are sex-biased in expression, we will better understand the underlying genetic basis of traits that are sexually dimorphic. Alreadly, studies of sex-biased genes in model organisms, particularly Drosophila, have revealed that male-biased genes are among the most rapidly evolving functional classes of genes. However, while a number of intrinsic factors appear to correlate with evolutionary rate (e.g., gene expression level, codon bias), it is unclear whether any of these factors drive the rapid divergence of male-biased genes. Another important discovery is the prevalence of sex-biased gene expression. However, even with widespread sexual dimorphism at the phenotypic level, it remains unknown the extent to which sex-biased gene expression exists in humans and their primate relatives. In fact, studies of sexual dimorphism on a molecular level in primates have been very few, even though understanding this phenomenon in humans could further our knowledge of the nature of sex-biased phenotypes and diseases. In this thesis, I advance our knowledge of the genetic bases and mechanisms that shape sexual dimorphism. First, I review a classic framework that biologists have traditionally applied to define and partition fitness measures between males and females in the model system, Drosophila. Second, I apply a molecular framework to compare the relative roles of intrinsic factors on the evolutionary rate of rapidly evolving male-biased genes in Drosophila. Third, I review the current state of our knowledge of sexual dimorphism and sex-biased gene expression in humans. Fourth, I present a bioinformatics framework to identify the extent of sex-biased expression in primate tissue and to examine the selective forces involved in their evolution. Overall, I demonstrate the effectiveness of using a functional comparative genomics approach in studying the nature of sexual dimorphism at the molecular level across multiple taxa. / Biology