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In modern data analysis, privacy is a critical concern when dealing with user-related databases. Ensuring user anonymity while extracting meaningful correlations from the data poses a significant challenge, especially when side information can potentially enable de-anonymization. This dissertation explores the standard information-theoretic problems in the correlated databases model. We define a "database" as a simple probabilistic model that contains a random feature vector for each user, with user labels shuffled to ensure anonymity. We first investigate correlation detection between two databases, formulating it as a composite binary hypothesis testing problem. Under the alternate hypothesis, there exists an unknown permutation that aligns users in the first database with those in the second, thereby matching correlated entries. The null hypothesis assumes that the databases are independent, with no such alignment. For the special case of Gaussian feature vectors, we derive both upper and lower bounds on the correlation required to achieve or fail to achieve this statistical problem. Our results are tight up to a constant factor when the feature length exceeds the number of users. Regarding our achievability boundary, we draw connections to the user labeling recovery problem, highlighting significant parallels and insights. Additionally, for the two databases model, we initially examine the potential gaps in the statistical analysis conducted thus far for the large number of users regime by drawing parallels with similar problems in the literature. Motivated by these comparisons, we propose a novel approach to address the detection problem, focusing on the hidden permutation structure and intricate dependencies characterizing these relationships. Building on our research, we present a comprehensive model for handling multiple correlated databases. In this multiple-databases setting, we address another fundamental information-theoretic problem: user label recovery. We evaluate the performance of the typicality matching estimator in relation to the asymptotic behavior of feature length, demonstrating an impossibility result that holds up to a multiplicative constant factor. This exploration into multiple databases not only broadens the scope of our study but also underscores the complexity and richness of correlation detection in a more generalized framework. In conclusion, we summarize the statistical gaps identified in our findings, exploring their possible origins. We also discuss the limitations of our simple probabilistic model and propose strategies to address them. Finally, we outline potential future research directions, including the information-theoretic problem of change detection, which remains an open area of significant interest.

Studies of mating systems and social organisation have been central to understanding of the evolution of social behaviour. The European badger Meles meles is a good species in which to study these processes, as its complex social system provides an opportunity to investigate how both natural and kin selection shape the evolution of mating systems and social structure. In this thesis, I use behavioural and genetic data to describe the mating system and social organisation of a high-density badger population and examine the occurrence of cooperative breeding. I genotyped 915 (85%) badgers trapped in Wytham Woods (1987–2005), 630 of which were cubs, and assigned both parents to 331 cubs with 95% confidence. This revealed a polygynandrous mating system, with up to five mothers and five fathers per social group. Mounting behaviour was also polygynandrous and I show the strongest evidence to date for multiple-paternity litters. I demonstrate, for the first time, that groups consisted of close and distant kin: approximately one third of group members were first-order kin, and overall group members had slightly lower relatedness levels than half-siblings. Within groups, adult and yearling females had higher pairwise relatedness than males, and neighbouring groups contained relatives. These findings result from the high level (42%) of extra-group paternities, 86% of which were assigned to neighbouring males. For the first time I show that females avoided inbreeding by mating with extra-group males; however, incestuous matings did occur. Promiscuous and repeated mountings were observed, which may reduce male–male aggression and infanticide, but may also promote sperm competition, genetic diversity, and / or genetic compatibility. Just under a third of adult males and females were assigned parentage each year and I quantify, for the first time, reproductive skew within badger groups. Correlations between relatedness, group productivity, and reproductive skew were not consistent with the predictions of incomplete-control models; rather, resource availability may play a role. Older and younger badgers displayed reduced annual breeding success, with male success increasing initially with experience. The Restraint, Constraint, and Selection Hypotheses did not explain the age-related breeding pattern in females. Variance in lifetime breeding success (LBS) was greater for males. Males that only bred within or only outside of their groups had half the LBS of males that did both. Females that were assigned maternity probably bred cooperatively and allonursed non-offspring, which has not been demonstrated previously. No benefit was established, however, in terms of litter size, probability of offspring breeding, or offspring lifetime breeding success, with more mothers in a group. In conclusion, badger social groups are fostered through kinship ties. Polygynandry and repeated mounting may have evolved originally to reduce male–male aggression and infanticide by males, through paternity masking. Although plural breeding occurs, group living appears to be costly. Motivation to disperse may be reduced through high-levels of extra-group paternities, which may also reduce inbreeding. Cooperative breeding among mothers may represent a low-cost behaviour with indirect benefits due to high levels of relatedness between female group-members. Badger sociality therefore represents an early stage in the evolution of social behaviour.

Sammanfattning Magisteruppsats för Civilekonomexamen i företagsekonomi, Ekonomihögskolan vid Linnéuniversitetet, Växjö, 2016.   Författare Alexander Palm & Adam Sjögren   Handledare Christopher Von Koch & Katarina Eriksson   Examinator: Sven-Olof Yrjö Collin   Titel: ”Aktierekommendationer i en ny tid – podcasts på den finansiella marknaden”   Bakgrund & problem: Aktierekommendationer ges traditionellt ut av diverse banker och analyshus. En bias har observerats vilket är till nackdel för investerare. Podcasts är ett förhållandevis nytt fenomen som kan erbjuda aktierekommendationer. Eftersom denna form av media är ny, finns lite forskning kring dess roll och potential för att erbjuda finansiella råd.   Syfte: Uppsatsens syfte är att utvidga forskning kring podcasts och dess roll för marknadsfunktionen och marknadseffektiviteten   Metod: En deduktiv utgångspunkt och ett kvantitativt förhållningssätt mellan teori och forskning tillämpas. En traditionell eventstudie med två olika tidsspann tillämpas för att studera aktierekommendationers påverkan på aktiekurser.   Slutsats: Resultat pekar på att IH inte har stöd vid aktierekommendationer från podcasts vilket är ett tecken på stöd för EMH. Däremot har PPH stöd vilket i sin tur pekar på brister i EMH. Således är det ett tecken på att den svenska aktiemarknaden inte är fullt effektiv och den besitter inte semi-stark form. Inget informationsläckage kunde observeras i samband med rekommendationerna, något som skiljer sig från traditionella källor. Vi kunde visa på en viss temporär och positiv effekt gällande marknadsfunktionen för Small Cap. Genom en observerad ökad handelsvolym påvisar vi övertro på den svenska aktiemarknaden, något som gäller även för traditionella aktierekommendationer. Vi kan inte statistiskt säkerställa att kunskaps sprids mellan podcastlyssnare vilket skiljer sig mot teorier och tidigare forskning. / Abstract Master Thesis in Business Administration. School of Business and Economics at Linnaeus University, Växjö, 2016.   Authors Alexander Palm & Adam Sjögren   Supervisor: Christopher Von Koch & Katarina Eriksson   Examiner: Sven-Olof Yrjö Collin   Title: “Stock recommendations in a new era – Podcasts in financial markets.”   Background & problem: Banks and other financial institutes deliver traditionally stock recommendations. Bias from these sources has been observed which can be of disadvantage for individual investors. Podcasts is a relatively new kind of media that can supply the market with stock recommendations. Since podcasts is a new media, there is little research regarding its role on financial markets and its potential to offer financial advice.   Purpose: The purpose is to extend previous research regarding podcasts and it’s role on market efficiency and market function.   Method: We apply a deductive benchmark and a quantitative approach. A traditional event study with two different time-spans is conducted to analyse stock recommendation and the effect on stock prices.   Conclusion: Results indicate lack of support for IH with stock recommendations from podcasts, which in turn is support for EMH. However, PPH does have support, which indicate deficiency in EMH. Thus, we provide evidence that the Swedish stock market is not fully efficient and doesn’t posses semi-strong form. No information leakage could be observed, something that differs from previous research on stock recommendations. We could provide evidence of a temporary and positive effect regarding the market function for Small Cap. The observed increase in trading volume proves overconfidence on the Swedish stock market, something that has previously been shown. No knowledge dispersion exists between listeners of podcasts, something that differs from theory and previous research.

<p>This work concerns the linguistic relativity hypothesis, also known as the Sapir-Whorf hypothesis, which, in its most general form claims that ‘lan-guage’ influences ‘thought’. Past studies into linguistic relativity have treated various aspects of both thought and language, but a growing body of literature has recently emerged, in this thesis referred to as neo-Whorfian, that empirically investigates thought and language from a cross-linguistic perspective and claims that the grammar or lexicon of a particular language influences the speakers’ non-linguistic thought.</p><p>The present thesis examines the assumptions about language that underlie this claim and criticizes the neo-Whorfian arguments from the point of view that they are based on misleading notions of language. The critique focuses on the operationalization of thought, language, and culture as separate vari-ables in the neo-Whorfian empirical investigations. The neo-Whorfian stud-ies explore language primarily as ‘particular languages’ and investigate its role as a variable standing in a causal relation to the ‘thought’ variable. Tho-ught is separately examined in non-linguistic tests and found to ‘correlate’ with language.</p><p>As a contrast to the neo-Whorfian view of language, a few examples of other approaches to language, referred to in the thesis as sociocultural appro-aches, are reviewed. This perspective on language places emphasis on prac-tice and communication rather than on particular languages, which are vie-wed as secondary representations. It is argued that from a sociocultural per-spective, language as an integrated practice cannot be separated from tho-ught and culture. The empirical findings in the neo-Whorfian studies need not be rejected, but they should be interpreted differently. The findings of linguistic and cognitive diversity reflect different communicational practices in which language cannot be separated from non-language.</p>

The degree to which biotic interactions influence invasion success may partly depend on the evolutionary relationship between invaders and native species. In particular, since host-use by enemies such as invertebrate herbivores and fungal pathogens tends to be phylogenetically conserved, exotic plants that have close native relatives in the invaded range should be more likely to interact with enemies. In this thesis, I explore this idea using a series of experiments and field surveys at nested taxonomic levels. My results indicate that exotics from multiple plant families experience lower damage if their average phylogenetic distance from locally co-occurring native family members is higher. I then demonstrate that within the Asteraceae, foliar and capitular damage are lower on exotic compared to native species. Both damage types had a relatively large phylogenetic component, but did not decline with phylogenetic distance to native or exotic confamilials. Finally, I show that communities with versus without close relatives are unlikely to differ in resistance to the novel invader, Solidago virgaurea: biotic resistance imposed by competitors, generalist vertebrates, and specialist invertebrates resulted in similar patterns of damage and mortality regardless of the presence of congeneric natives. In some cases, effects of biota were positive: growth of S. virgaurea seedlings in soils collected near congeneric natives was enhanced more than in soils from communities where congenerics were absent. Overall, these results suggest that biotic interactions between exotic and native species can be phylogenetically structured, although trends based on distance measures tend to be weak. In some cases, damage does decline with phylogenetic distance to native species; however this trend is unlikely to be a strong force limiting invasion or structuring plant communities. These results have significant implications for current theories of invasion biology including the "Enemy Release Hypothesis" and "Darwin's Naturalization Hypothesis", as well as for community phylogenetics.

When selecting a method for testing variance equality, a researcher should select a method which is robust to distribution non-normality and dissimilarity. The method should also possess sufficient power to ascertain departures from the equal variance hypothesis. This Monte Carlo study examined the robustness and power of five tests of variance equality under specific conditions. The tests examined included one procedure proposed by O'Brien (1978), two by O'Brien (1979), and two by Conover, Johnson, and Johnson (1981). Specific conditions included assorted combinations of the following factors: k=2 and k=3 groups, normal and non-normal distributional forms, similar and dissimilar distributional forms, and equal and unequal sample sizes. Under the k=2 group condition, a total of 180 combinations were examined. A total of 54 combinations were examined under the k=3 group condition. The Type I error rates and statistical power estimates were based upon 1000 replications in each combination examined. Results of this study suggest that when sample sizes are relatively large, all five procedures are robust to distribution non-normality and dissimilarity, as well as being sufficiently powerful.

A sinalização, formação e descoberta de preços agrícolas são adequadas se refletem rapidamente todas as informações recebidas pelos seus participantes. Então, quando o mercado é eficiente, possibilita eficiência alocativa, redução de imprecisão nas decisões dos agentes e dos custos informacionais. Entretanto, os agentes do agronegócio podem tomar decisões errôneas de produção, comercialização e estocagem, sujeitas ao conjunto de informações incompletas contidas nos preços passados, se os mercados forem não eficientes. Nesse contexto, o objetivo geral foi analisar a eficiência dos mercados futuros de commodities. Para atingi-lo, estruturou-se esta pesquisa em três ensaios. No primeiro, objetivou-se testar a hipótese de passeio aleatório a contratos futuros agropecuários negociados na BM&FBOVESPA. Refutá-la significa possível previsibilidade e, por conseguinte, os mercados não seriam fracamente eficientes. Correlações seriais e testes de razão de variância foram utilizados para verificá-las. Os resultados deram suporte à hipótese de passeio aleatório nos mercados futuros de café e da soja, eficientes na forma fraca, e evidências contrárias foram encontradas nos mercados do boi gordo, milho e etanol. No segundo, o objetivo foi investigar a eficiência e formações de clusters nos contratos futuros do complexo soja (soja, farelo de soja e óleo de soja) negociados nas bolsas de commodities: argentina, brasileira, chinesa, indiana, japonesa, norte-americana e sul-africana. Com base na métrica obtida por distância euclidiana de razões de variância, evidenciaram-se dependências similares dos mercados, as quais podem ser interpretadas como efeito espraiamento da eficiência informacional. Os agentes devem, portanto, manter percepções em relação aos diversos mercados devido às sinalizações interdependentes dos preços. No terceiro, objetivou-se analisar a eficiência dos mercados futuros agropecuários brasileiros, sob a hipótese adaptativa de mercado. Utilizando propostas recentes à não linearidade e razão de variância, encontrou-se que as elevadas rejeições à hipótese de diferença martingal se encontram nos mercados em que as intervenções governamentais se fazem presentes: milho e etanol. Nos mercados de café, boi gordo e soja ocorreram menores rejeições à hipótese martingal e, portanto, houve maior eficiência informacional. Essas evidências--consistentes com a hipótese adaptativa dos mercados--justificam operações de hedge dinâmicas, bem como a gerência de carteiras de investimentos de forma ativa. / Agricultural prices\' formation, discovery and signalling only are accurate when they can rapidly reflect all new information faced by its market agents. Thereby, when a given market is efficient, it allows for allocative efficiency, reducing inefficiencies both in decision-making process and in informational costs. On the other hand, when markets are said not to be efficient, agribusinesses\' agents can make mistaken production, marketing and storage decisions, once such decisions are due to incomplete information contained in past prices. In this context, the main purpose of this study is to analyze the efficiency in future markets of commodities. In order to achieve its final goal, the study has been structured in three essays. In the first essay, the random walk hypothesis has been tested for agricultural future contracts from Brazilian Securities, Commodities and Futures Exchange (BMF&BOVESPA). Refusing the hypothesis for a given commodity implies some degree of predictability, therefore inconsistent even with a weak notion of efficiency. These tests were carried out using serial correlations and variance ratios. The results show the presence of random walks in coffee and soybean future markets, and contrary evidences (absence of random walks) in live cattle, corn and ethanol future markets. In the second essay, it has been analyzed the efficiency and the presence of clusters in the soybean complex future contracts (soybean, soybean meal and soybean oil) traded in the following future markets: Argentina (MTB), Brazil (BVMF), China (DCE), India (NCD), Japan (TKT), US (CBT) and South-Africa (SAF). Based on the metrics obtained by Euclidian distances of variance ratios, similar dependencies have been found for all markets, which suggest informational efficiency spreading. Agents, therefore, shall maintain perceptions over several international markets, given the interdependence found for prices in distinct future markets. In the third one, the adaptive market hypothesis has been tested for agricultural future markets in Brazil. Applying more recent approaches to Nonlinearity and Variance Ratio tests, high rejections to martingale difference hypothesis took place in agricultural markets which governmental interference is highly persistent, i.e., corn and ethanol. In coffee, live cattle and soybeans markets, weaker rejections to the martingale hypothesis hint higher informational efficiency. These evidences, consistent with the adaptive market hypothesis, justify dynamic hedge operations, as well as an active management of investment portfolios in such markets.

Animal communication transmits information using different sensory signals that have particular purposes (e.g. courtship, territorial defense, maintaining groups together and minimizing predation) and are susceptible to habitat pressures (Sensory Drive Hypothesis - SDH). In birds, some studies on acoustic and visual signals showed that song structure is associated with sound transmission capacity in different habitats and some plumage features (e.g. color, brightness and pattern) seem to vary according to light conditions of the environment. In addition to habitat effects, other factors such as energetic limits, predation, and parasitism risk can limit the investment in more than one type of sensory signal. Due to this high cost, it was proposed the existence of an evolutionary trade-off between the different types of sensory signals termed Transfer (TH) or Trade-off hypothesis. Few studies that have tested the TH in birds showed contrasting results, being corroborated only in two studies. Also, there is a low in the number of studies that have considered habitat conditions as covariates (SDH). Here, we assess the TH between acoustic and visual signals, while simultaneously considering potential effects of habitat conditions (SDH) in a diverse group of Neotropical suboscine birds, commonly known as antbirds (Thamnophilidae). Specifically, we integrated a genome-scale phylogeny of the tribe Formicivorini (36 species) with vocal, plumage, ecological, and behavioral data within a phylogenetic comparative framework to simultaneously test the TH and SDH while assessing the influence of mixed-species flocking foraging behavior on the structural diversity of acoustic and visual signals. Whereas in both sexes we found significant trade-offs between some plumage and vocal traits (e.g. dorsal luminance versus frequency slope), providing support for the TH, we found a non-significant opposite trend between plumage and vocal sexual dimorphism. All these relationships are influenced by habitat conditions and behavioral traits as covariates, corroborating the SDH and mixed-species flocking behavior influence in the evolution of visual and acoustic signals / A comunicação animal transmite informações usando diferentes tipos de sinais sensoriais que possuem propósitos específicos (e.g. cortejo, defesa territorial, manutenção de grupos unidos e minimização da predação) e estão suscetíveis a pressões do habitat (Hipótese de Condução Sensorial - HCS). Em aves, alguns estudos de sinais acústicos e visuais demonstraram que a estrutura do canto está associada com a capacidade de transmissão do som em diferentes habitats e alguns aspectos de plumagem (e.g. coloração, brilho e padrão) parecem variar de acordo com as condições de iluminação do ambiente. Além dos efeitos de habitat, outros fatores como limitação energética, risco de predação e de parasitismo podem limitar o investimento em mais de um tipo de sinal sensorial. Devido a esse alto custo, foi proposta a existência de uma demanda conflitante (trade-off) evolutiva entre os diferentes tipos de sinais sensoriais denominada Hipótese de Transferência (HT) ou de \"Trade-off\". Os poucos estudos que testaram a HT em aves apresentaram resultados contrastantes, sendo corroborada apenas em dois trabalhos. Além disso, há uma baixa quantidade de trabalhos que consideraram as condições de habitat como covariáveis. Assim, nós avaliamos a HT entre os sinais acústicos e visuais, considerando simultaneamente os efeitos potenciais das condições de habitat (HCS) em um diverso grupo de aves subóscines neotropicais, comumente conhecidas como papa-formigas (Thamnophilidae). Especificamente, nós integramos a filogenia em escala genômica da tribo Formicivorini (36 espécies) com dados vocais, de plumagem, ecológicos e comportamentais utilizando uma abordagem comparativa filogenética para testar simultaneamente a HT, a HCS e também considerando a influência do comportamento de formação de bandos mistos na diversidade da estrutura dos sinais acústicos e visuais. Enquanto que demandas conflitantes significativas entre algumas medidas de plumagem e de canto foram encontradas em ambos os sexos (e.g. luminância dorsal contra declive de frequência) corroborando a HT, uma tendência oposta não significativa foi encontrada entre o dimorfismo sexual de plumagem e canto. Todas essas relações são influenciadas por condições de habitat e comportamento como covariáveis, corroborando a HCS e a influência do comportamento de bandos mistos na evolução da estrutura dos sinais acústicos e visuais