Recognizing and realizing cactus metrics

The problem of realizing finite metric spaces in terms of weighted graphs has many applications. For example, the mathematical and computational properties of metrics that can be realized by trees have been well-studied and such research has laid the foundation of the reconstruction of phylogenetic trees from evolutionary distances. However, as trees may be too restrictive to accurately represent real-world data or phenomena, it is important to understand the relationship between more general graphs and distances. In this paper, we introduce a new type of metric called a cactus metric, that is, a metric that can be realized by a cactus graph. We show that, just as with tree metrics, a cactus metric has a unique optimal realization. In addition, we describe an algorithm that can recognize whether or not a metric is a cactus metric and, if so, compute its optimal realization in $O(n^3)$ time, where $n$ is the number of points in the space

Ecological Niches, Species Distributions, And Biogeographic Processes In Rodents On Neotropical Sky Islands

This dissertation focused on the methodological and theoretical improvement of correlative ecological niche models (ENMs) to better understand the processes governing species distributions and associated evolutionary divergence in rodents inhabiting mesic conditions in the Neotropics. Focusing on a widespread rodent from northern South America (Heteromys anomalus), in the first chapter I proposed and tested a methodological approach to surmount the challenge of incorporating environmental information from the margins of species geographic ranges into ENMs. In so doing, I argue how populations that exist on the borders of species\u27 local ranges (spatial margins) can lead to exaggerated estimates of their niches and potential geographic distributions due to issues of variable choice and resolution. In the second chapter, I demonstrated how the approach developed in Chapter 1 improved the ability of ENMs to detect an obvious environmental barrier fostering isolation and potential divergence between continental and peninsular populations in three rodent lineages in northern South America: Proechimys guairae, Rhipidomys venezuelae, and the Heteromys anomalus/H. oasicus species pair. In the third chapter, I integrated ENMs with molecular data to test the effect of the climatic oscillations of the late Quaternary Period in two species of rodents restricted to the sky islands of Costa Rica and western Panama: Reithrodontomys creper and Nephelomys devius. Overall, results revealed how, despite sharing similar distribution patterns, niche differences in these species resulted in idiosyncratic responses to past climate change that match currently observed patterns of genetic diversity. Finally, in the fourth chapter, I developed a perspective of the ecological niche concept that takes into account the responsiveness of phenotypes and the variability of ecological strategies that a species can perform. Integrating these aspects into niche theory leads to a more holistic perspective that reduces conflict between niche definitions, dissolves existing paradoxes, and has multiple implications for the study of niches, their evolution, and their effect on lineage divergence. Overall, this dissertation contributes to the conceptual and methodological development of correlative approaches for modeling species Grinnellian niches and their associated potential geographic distributions; the understanding of how these relate to the evolutionary history of Neotropical montane taxa with regards to past climate change; and finally, to a more holistic perspective of the niche concept that has multiple implications for the study of niches in general, as well as our understanding of how they evolve and affect lineage divergence

Natural Resources Management Research Impacts : Evidence from the CGIAR

This document presents the results of SPIA’s initiative to assess the impacts of past investments in NRMR in the CG system. NRMR encompasses research on land, water and biodiversity resources management. It focuses on generating knowledge that results in technology options and how to sustainably enhance the productivity and stability of ecosystem resources. The initiative was a response to concerns on the dearth of documented credible evidence that NRMR substantially contributes to realizing the CGIAR mission on poverty, food security and the environment. SPIA commissioned five impact assessment case studies associated with the research of five CG centers. Two more centers volunteered case studies for inclusion in the overall exercise, on the understanding that their case studies would undergo the same rigorous peer review as the original five. The seven case studies are the main focus of the SPIA NRMR impact assessment initiative. This report also carries results from the Alternatives to Slash-and-Burn Programme (ASB). However, the report only provides summaries of, and commentary on, the case studies. The complete case studies will appear in a forthcoming book to be published by CABI. The seven impact assessments included case studies from CIAT, CIFOR, CIMMYT, ICARDA, ICRAF, IWMI and WorldFish Center

Coopetition in an open-source way : lessons from mobile and cloud computing infrastructures

An increasing amount of technology is no longer developed in-house. Instead, we are in a new age where technology is developed by a networked community of individuals and organizations, who base their relations to each other on mutual interest. Advances arising from research in platforms, ecosystems, and infrastructures can provide valuable knowledge for better understanding and explaining technology development among a network of firms. More surprisingly, recent research suggests that technology can be jointly developed by rival competing firms in an open-source way. For instance, it is known that the mobile device makers Apple and Samsung continued collaborating in open-source projects while running expensive patent wars in the courts. On top of multidisciplinary theory in open-source software, cooperation among competitors (aka coopetition) and digital infrastructures, I (and my coauthors) explored how rival firms cooperate in the joint development of open-source infrastructures. While assimilating a wide variety of paradigms and analytical approaches, this doctoral research combined the qualitative analysis of naturally occurring data (QA) with the mining of software repositories (MSR) and social network analysis (SNA) within a set of case studies. By turning to the mobile and cloud computing industries in general, and the WebKit and OpenStack opensource infrastructures in particular, we found out that qualitative ethnographic materials, combined with social network visualizations, provide a rich medium that enables a better understanding of competitive and cooperative issues that are simultaneously present and interconnected in open-source infrastructures. Our research contributes back to managerial literature in coopetition strategy, but more importantly to Information Systems by addressing both cooperation and competition within the development of high-networked open-source infrastructures.Yhä suurempaa osaa teknologiasta ei enää kehitetä organisaatioiden omasta toimesta. Sen sijaan, olemme uudella aikakaudella jossa teknologiaa kehitetään verkostoituneessa yksilöiden ja organisaatioiden yhteisössä, missä toimitaan perustuen yhteiseen tavoitteeseen. Alustojen, ekosysteemien ja infrastruktuurien tutkimuksen tulokset voivat tuottaa arvokasta tietämystä teknologian kehittämisestä yritysten verkostossa. Erityisesti tuore tutkimustieto osoittaa että kilpailevat yritykset voivat yhdessä kehittää teknologiaa avoimeen lähdekoodiin perustuvilla käytännöillä. Esimerkiksi tiedetään että mobiililaitteiden valmistajat Apple ja Samsung tekivät yhteistyötä avoimen lähdekoodin projekteissa ja kävivät samaan aikaan kalliita patenttitaistoja eri oikeusfoorumeissa. Perustuen monitieteiseen teoriaan avoimen lähdekoodin ohjelmistoista, yhteistyöstä kilpailijoiden kesken (coopetition) sekä digitaalisista infrastruktuureista, minä (ja kanssakirjoittajani) tutkimme miten kilpailevat yritykset tekevät yhteistyötä avoimen lähdekoodin infrastruktuurien kehityksessä. Sulauttaessaan runsaan joukon paradigmoja ja analyyttisiä lähestymistapoja case-joukon puitteissa, tämä väitöskirjatutkimus yhdisti luonnollisesti esiintyvän datan kvantitatiivisen analyysin ohjelmapakettivarastojen louhintaan ja sosiaalisten verkostojen analyysiin. Tutkiessamme mobiili- ja pilvipalveluiden teollisuudenaloja yleisesti, ja WebKit ja OpenStack avoimen lähdekoodin infrastruktuureja erityisesti, havaitsimme että kvalitatiiviset etnografiset materiaalit yhdistettyinä sosiaalisten verkostojen visualisointiin tuottavat rikkaan aineiston joka mahdollistaa avoimen lähdekoodin infrastruktuuriin samanaikaisesti liittyvien kilpailullisten ja yhteistyökuvioiden hyvän ymmärtämisen. Tutkimuksemme antaa oman panoksensa johdon kirjallisuuteen coopetition strategy -alueella, mutta sitäkin enemmän tietojärjestelmätieteeseen, läpikäymällä sekä yhteistyötä että kilpailua tiiviisti verkostoituneessa avoimen lähdekoodin infrastruktuurien kehitystoiminnassaUma crescente quantidade de tecnologia não é desenvolvida internamente por uma só organização. Em vez disso, estamos em uma nova era em que a tecnologia é desenvolvida por uma comunidade de indivíduos e organizações que baseiam suas relações umas com as outras numa rede de interesse mútuo. Os avanços teórico decorrentes da pesquisa em plataformas computacionais, ecossistemas e infraestruturas digitais fornecem conhecimentos valiosos para uma melhor compreensão e explicação do desenvolvimento tecnológico por uma rede de multiplas empresas. Mais surpreendentemente, pesquisas recentes sugerem que tecnologia pode ser desenvolvida conjuntamente por empresas rivais concorrentes e de uma forma aberta (em código aberto). Por exemplo, sabe-se que os fabricantes de dispositivos móveis Apple e Samsung continuam a colaborar em projetos de código aberto ao mesmo tempo que se confrontam em caras guerras de patentes nos tribunais. Baseados no conhecimento científico de software de código aberto, de cooperação entre concorrentes (também conhecida como coopetição) e de infraestruturas digitais, eu e os meus co-autores exploramos como empresas concorrentes cooperam no desenvolvimento conjunto de infraestruturas de código aberto. Ao utilizar uma variedade de paradigmas e abordagens analíticas, esta pesquisa de doutoramento combinou a análise qualitativa de dados de ocorrência natural (QA) com a análise de repositórios de softwares (MSR) e a análise de redes sociais (SNA) dentro de um conjunto de estudos de casos. Ao investigar as industrias de technologias móveis e de computação em nuvem em geral, e as infraestruturas em código aberto WebKit e OpenStack, em particular, descobrimos que o material etnográfico qualitativo, combinado com visualizações de redes sociais, fornece um meio rico que permite uma melhor compreensão das problemas competitivos e cooperativos que estão simultaneamente presentes e interligados em infraestruturas de código aberto. A nossa pesquisa contribui para a literatura em gestão estratégica e coompetição, mas mais importante para literatura em Sistemas de Informação, abordando a cooperação e concorrência no desenvolvimento de infraestruturas de código aberto por uma rede the indivíduos e organizações em interesse mútuo

Exploring the Intersection Between Psychedelics and The 4 P’s of Creativity

Psychedelics are extremely multifaceted and complex hallucinogenic compounds that induce an altered state of consciousness and can have a wide range of effects. The outcomes of one’s psychedelic experience are largely dependent on what’s known as “set and setting.” The purpose of this project is to make an argument that the lens through which we look at and explore psychedelics matters. Currently the primary lens through which Western culture is exploring exploring psychedelics is through the lens of reducing mental illness. When we look at the existing scientific research that focuses on psychedelics as a treatment for mental illness, and we re-read this literature through the lens of deeply understanding creativity research, one can make a strong argument that the same reasons that psychedelics help to treat depression or addiction, for example, are the same underlying mechanisms for which psychedelics can help to foster greater creative thinking. This project makes a case that despite the lack of scientific research explicitly exploring the connection between psychedelics and creativity, we can start to highlight and connect hidden dots that make an argument that psychedelics can indeed enhance various aspects of creativity. This project specifically explores how psychedelics relate to the 4 P’s of Creativity. Through this project and the review of the existing literature, I came to understand that the very core overlap between psychedelics and creativity is a mode of cognition called unconstrained cognition, strengthening my understanding of how psychedelic experiences can support the multifaceted nature of creativity. I believe this to be the next frontier in psychedelic research because it’s essentially the second half of the same equation of mental health. I consider the curriculum I am developing to be like a helpful roadmap for both psychedelic preparation and integration, specifically for leaders who want to not only develop their leadership skills but who also want to develop their capacities to think more creatively

Index appearance record with preorders

Transforming ω-automata into parity automata is traditionally done using appearance records. We present an efficient variant of this idea, tailored to Rabin automata, and several optimizations applicable to all appearance records. We compare the methods experimentally and show that our method produces significantly smaller automata than previous approaches

Toward decolonized conceptions of space and literature of place in ecocritical analysis : the process and production of landscape in William Bartram's travels and Samuel Hearne's a journey to the Northern Ocean

The tendency to stage appreciation for and attention to nature as a passive, guiltless enterprise was necessary for eighteenth-century colonial claims to space, but it also remains a very deeply entrenched aspect of environmentalist attitudes today. Indeed, innovations that shaped the technological interpretation and inscription of place in the latter eighteenth century have strongly situated contemporary North American environmental discourses.This thesis explores the methods of spatial representation in Samuel Hearne’s A Journey from Prince of Wales’s Fort, in Hudson’s Bay, to the Northern Ocean(1795) and William Bartram’s Travels Through North and South Carolina, Georgia, East and West Florida, The Cherokee Country, The Extensive Territories of the Muscogulges or Creek Confederacy, and the Country of the Choctaws (1792). Both ecocritical and postcolonial methods underlay an analysis of the discourses and rhetorics of space exhibited in the North American travel writing of these two late-eighteenth-century writers. A first move monitors how landscape accrues not only as a product of descriptive techniques, frames, and screens, but also as a process whereby narrative identity is formed against and within a represented landscape. A second move locates these texts as versions of Mary Louise Pratt’s “anti-conquest,” in which the hero-explorer of colonial encounter is staged as both passive and innocent.Two primary results from this research into the relationship between literature and environment are reported. First, according to conventions of ecocritical analysis, Hearne and Bartram implement two very different modes of spatial representation in travel narratives from the same period; in the broadest strokes, Hearne’s text is deeply anthropocentric and only partially engages in eighteenth-century vogues of natural history, while Bartram’s is compellingly and precociously ecocentric as well as deeply invested in the commerce of Linnaean systemizations of nature that revolutionized natural history in the period. Second, this disparity in representational method is correlated not only with variances in the ecological (or green) sensibilities of the authors, but also with distinctions in the colonial functionality of the texts, verifying that literature of place, despite the putative object of description, always already maintains significant valencies in social registers