University of British Columbia

About: University of British Columbia is a education organization based out in Vancouver, British Columbia, Canada. It is known for research contribution in the topics: Population & Poison control. The organization has 89939 authors who have published 209679 publications receiving 9226862 citations. The organization is also known as: UBC & The University of British Columbia.

Horizontal gene transfer in eukaryotic evolution

Abstract: Horizontal gene transfer (HGT; also known as lateral gene transfer) has had an important role in eukaryotic genome evolution, but its importance is often overshadowed by the greater prevalence and our more advanced understanding of gene transfer in prokaryotes. Recurrent endosymbioses and the generally poor sampling of most nuclear genes from diverse lineages have also complicated the search for transferred genes. Nevertheless, the number of well-supported cases of transfer from both prokaryotes and eukaryotes, many with significant functional implications, is now expanding rapidly. Major recent trends include the important role of HGT in adaptation to certain specialized niches and the highly variable impact of HGT in different lineages.

Conservative prior distributions for variance parameters in hierarchical models

Abstract: Bayesian hierarchical models typically involve specifying prior distributions for one or more variance components. This is rather removed from the observed data, so specification based on expert knowledge can be difficult. While there are suggestions for "default" priors in the literature, often a condi tionally conjugate inverse-gamma specification is used, despite documented drawbacks of this choice. The authors suggest "conservative" prior distributions for variance components, which deliberately give more weight to smaller values. These are appropriate for investigators who are skeptical about the presence of variability in the second-stage parameters (random effects) and want to particularly guard against inferring more structure than is really present. The suggested priors readily adapt to various hierarchical modelling settings, such as fitting smooth curves, modelling spatial variation and combining data from multiple sites. Lois a priori conservatrices pour les parametres de variance de modeles hierarchiques Rgsum6: Les modeles bay6siens hierarchiques comportent g6n6ralement une ou des composantes de va riance que l'on doit doter de lois a priori. Le choix de ces lois est delicat car la variation est un aspect des donn6es difficile a cemer. De toutes les lois a priori "par defaut," une loi conjuguee inverse-gamma con ditionnelle est la plus souvent employ6e, malgr6 ses inconvenients. Les auteurs proposent des lois a priori "conservatrices" pour les composantes de la variance qui privilegient les petites valeurs. Elles conviennent bien aux situations oiu le chercheur s'interroge sur la presence r6elle de variabilit6 dans les parametres de deuxieme degre (effets aleatoires) et qu'il veut eviter d'imposer une structure artificielle. Les lois a priori sugg6rdes s'adaptent A diverses situations propices a la mod6lisation hierarchique, notamment l'ajustement de courbes lisses et la modelisation de variation spatiale ou de donn6es issues de nombreux sites.

A Description of the Affective Quality Attributed to Environments

Abstract: The meaning that persons attribute to environments is divided into perceptualcognitive meaning and affective meaning. Affective meaning is then conceptualized as a two-dimensional bipolar space that can be denned by eight variables falling in the following circular order around the perimeter: pleasant (arbitrarily set at 0°), exciting (45°), arousing (90°), distressing (135°), unpleasant (180°), gloomy (225°), sleepy (270°), and relaxing (315°, which is thus 45° from pleasant). Alternatively, the same space can be denned by two orthogonal bipolar dimensions of pleasant-unpl easant and arousing-sleepy—or equally well by exciting-gloomy and distressing-relaxing. Reliable verbal scales for these eight variables are developed and shown to approximate the proposed theoretical structure. Most of us would acknowledge the pervasive if subtle influence of affective responses on person-environment interactions. The English language provides hundreds of words, such as lively, boring, disgusting, and relaxing, that persons use to describe the affective quality of places. In spite of, or perhaps because of, this large array of affective descriptors, environmental psychologists have focused their attention on only a few and then only one at a time (such as degree of comfort, annoyance, pleasantness, or psychological stress), implicitly expressing pessimism about the possibility of including in their research or theorizing anything approaching a complete description and assessment of the affective quality attributed to places. Our thesis is that a very simple conceptualization can encompass the diverse affective concepts applied to molar physical environments. Theorists from widely differing vantage

Contributions of cultural services to the ecosystem services agenda.

Abstract: Cultural ecosystem services (ES) are consistently recognized but not yet adequately defined or integrated within the ES framework. A substantial body of models, methods, and data relevant to cultural services has been developed within the social and behavioral sciences before and outside of the ES approach. A selective review of work in landscape aesthetics, cultural heritage, outdoor recreation, and spiritual significance demonstrates opportunities for operationally defining cultural services in terms of socioecological models, consistent with the larger set of ES. Such models explicitly link ecological structures and functions with cultural values and benefits, facilitating communication between scientists and stakeholders and enabling economic, multicriterion, deliberative evaluation and other methods that can clarify tradeoffs and synergies involving cultural ES. Based on this approach, a common representation is offered that frames cultural services, along with all ES, by the relative contribution of relevant ecological structures and functions and by applicable social evaluation approaches. This perspective provides a foundation for merging ecological and social science epistemologies to define and integrate cultural services better within the broader ES framework.

Seaweed ecology and physiology

Abstract: Part I. Morphology, Life Histories and Morphogenesis: 1. Introduction: the plants and their environments 2. Seaweed morphology and anatomy 3. Seaweed cells 4. Seaweed genetics and molecular biology 5. Seaweed life histories 6. Settlement and germination 7. Thallus morphogenesis 8. Synopsis Part II. Seaweed Communities: 1. Seaweed communities T. A. Norton et al. 2. Intertidal zonation patterns 3. Submerged zonation patterns 4. Some other seaweed habitats and communities P. H. Nienhuis et al. 5. Community analysis 6. Synopsis Part III. Biotic Interactions: 1. Competition 2. Grazing 3. Symbiosis 4. Synopsis Part IV. Light and Photosynthesis: 1. An overview of photosynthesis 2. Irradiance 3. Light harvesting 4. Carbon fixation: the 'dark reactions' of photosynthesis 5. Seaweed polysaccharides 6. Carbon translocation 7. Photosynthetic rates and primary productivity 8. Synopsis Part V. Nutrients: 1 Nutrient requirements 2. Nutrient availability in seawater 3. Pathways and barriers to ion entry 4. Nutrient uptake kinetics 5. Uptake, assimilation and metabolic role of essential nutrients 6. Long distance transport translocation 7. Growth kinetics 8. Effects of nutrient supply 9. Synopsis Part VI. Temperature and Salinity: 1. Natural ranges of temperature and salinity 2. Temperature effects 3. Biochemical and physiological effects of salinity 4. Dessication 5. Salinity-temperature interactions and estuarine distribution 6. Synopsis Part VII. Water Motion: 1. Water flow over surfaces 2. Wave action 3. Synopsis Part VIII. Pollution: 1. Introduction 2. Thermal pollution 3. Heavy metals 4. Oil 5. Synthetic organic chemicals 6. Complex wastes and eutrophication 7. Synopsis Part IX. Seaweed Mariculture: 1. Introduction 2. Porphyra mariculture 3. Lamineria mariculture 4. Undaria mariculture 5. Eucheuma and Kappaphycus mariculture 6. Other seaweeds 7. Domestication of seaweeds - application of ecology and physiology 8. Seaweed biotechnology 9. Synopsis Appendix: Taxonomic classification of algae mentioned in the text P. C. Silva and R. L. Moe Index.