119 research outputs found

    Rational Vs Emotional Appeals with Communications to Landholders: A Review of Focus Group Responses

    Full text link
    There are many organisations that seek to communicate with landholders for the purposes of engaging them in local environmental or conservation programs and sustainable production. This study examined whether different segments of landholders are likely to respond better to communication based on different appeals (rational or emotional), using different messages and communication channels. Seven hypothetical communication campaigns were designed with specific messages and appeals, each produced in three types of media. Focus groups of three specific landholder groups lifestylers., traditional and absentee landowners were held to obtain their responses to the campaigns. Findings suggest that the effectiveness of communications with landholders can be increased by using preferred messages and appeals, and selecting a combination of media appropriate to the landholder group being targeted

    Cheating on the Edge

    Get PDF
    We present the results of an individual agent-based model of antibiotic resistance in bacteria. Our model examines antibiotic resistance when two strategies exist: “producers”–who secrete a substance that breaks down antibiotics–and nonproducers (“cheats”) who do not secrete, or carry the machinery associated with secretion. The model allows for populations of up to 10,000, in which bacteria are affected by their nearest neighbors, and we assume cheaters die when there are no producers in their neighborhood. Each of 10,000 slots on our grid (a torus) could be occupied by a producer or a nonproducer, or could (temporarily) be unoccupied. The most surprising and dramatic result we uncovered is that when producers and nonproducers coexist at equilibrium, nonproducers are almost always found on the edges of clusters of producers

    Rutas trĂłficas en macrozooplancton del Lago de Tota - BoyacĂĄ, Colombia

    Get PDF
    1 recurso en lĂ­nea (56 pĂĄginas) : ilustraciones, figuras, tablas.In aquatic ecosystems inputs of matter and energy present in greater or lesser extent depending on the basin, given the origin and quality of these resources, you can alter the balance in metabolism or interactions in the food web. Using stable isotopes of carbon and nitrogen, the link between potential sources of funds and use established by macrozooplankton species in Lake Big and Lake Fellow the Lake Tota sectors. Trophic possible ways the role of each species in the proposed network, as well. In general, most of this study, most species have a bond with the autotrophic pathway, being the phytoplankton the food resource base for the food web, commonly found impoverished carbon signals. Particularly, the analysis showed a variation in the source or resource for two species (Daphnia laevis and Bosmina (Bosmina) cf. longirostris), with an enrichment in its signal to 19.92 ‰ -20.34 ‰ ÎŽ13C, which can be given by plasticity in their food supply, and even if Boeckella gracilis having a signal indicating a specialization in its appeal with carbon impoverished -30 to -26 ‰ values ÎŽ13C while nitrogen values are enriched with an average value 20.21 ‰ in ÎŽ15N. To set the trophic fractionation means establishing three groups, the first (herbivores) consisting of (D. laevis, B. (Bosmina) and Ceriodaphnia pulchella cf. longirostris), the second (omnivore) which is (Daphnia pulex, Macrocyclops sp. and Cyclopoida), and a third group (secondary consumer) where is the only calanoido B. gracilis. In comparing the temporal variation is observed that there is a significant change in signals ÎŽ13C and ÎŽ15N of some species in relation to the influence of sources and allochthonous or autochthonous origin, spatial variation was not significant. It is concluded that the macrozooplanton Lake Tota, has a strong link with the autotrophic pathway and pelagic trophic levels have 3 sections, plus the primary producers and the food web in general tends to have an amplitude of trophic niche.En los ecosistemas acuĂĄticos se presentan aportes de materia y energĂ­a, en mayor o menor proporciĂłn dependiendo de su cuenca, dado el origen y calidad de estos recursos, se puede alterar el balance en el metabolismo o las interacciones en la red trĂłfica. Utilizando los isotopos estables de Carbono y NitrĂłgeno, se estableciĂł el vĂ­nculo entre fuentes potenciales de recursos y el uso por las especies del macrozooplancton en los sectores Lago grande y Lago chico del lago de Tota (BoyacĂĄ). AsĂ­, se propusieron las posibles vĂ­as trĂłficas y el rol de cada especie en la red. En general, en la mayor parte de este estudio, las especies tuvieron un vĂ­nculo marcado con la vĂ­a autotrĂłfica, siendo el fitoplancton el recurso alimenticio base para la red trĂłfica, encontrando comĂșnmente señales empobrecidas de carbono. Particularmente, el anĂĄlisis mostrĂł una variaciĂłn en la fuente o recurso para dos especies (Daphnia laevis y Bosmina (Bosmina) cf. longirostris), con un enriquecimiento en su señal de 19.92‰ ÎŽ13C a -20.34‰ ÎŽ13C, lo que se puede dar por una plasticidad en su fuente alimenticia, e incluso el caso de Boeckella gracilis que tiene una señal que indica una especializaciĂłn en su recurso con valores empobrecidos de carbono -30 a -26‰ ÎŽ13C mientras que los valores de nitrĂłgeno son enriquecidos con un valor promedio de 20.21‰ en ÎŽ15N. Para establecer el fraccionamiento trĂłfico medio se formaron tres grupos, el primero (herbĂ­voros) conformado por (D. laevis, B. (Bosmina) cf. longirostris y Ceriodaphnia pulchella), el segundo (omnĂ­voro) en el que se encuentra (Daphnia pulex, Macrocyclops sp. y Cyclopoida), y un tercer grupo (Consumidor secundario) donde esta B. gracilis el Ășnico calanoido. En la comparaciĂłn de la variaciĂłn temporal, se observa que hay un cambio significativo en las señales de ÎŽ13C y ÎŽ15N de algunas especies en relaciĂłn a la influencia de las fuentes y su origen alĂłctono o autĂłctono, la variaciĂłn espacial no fue significativa. Se concluye que el macrozooplanton del lago de Tota, tiene un fuerte vĂ­nculo con la vĂ­a autotrĂłfica y que los niveles trĂłficos pelĂĄgicos tienen 3 eslabones, mĂĄs los productores primarios, y la red trĂłfica en general tiende a tener una amplitud del nicho trĂłfico. En los ecosistemas acuĂĄticos se presentan aportes de materia y energĂ­a, en mayor o menor proporciĂłn dependiendo de su cuenca, dado el origen y calidad de estos recursos, se puede alterar el balance en el metabolismo o las interacciones en la red trĂłfica. Utilizando los isotopos estables de Carbono y NitrĂłgeno, se estableciĂł el vĂ­nculo entre fuentes potenciales de recursos y el uso por las especies del macrozooplancton en los sectores Lago grande y Lago chico del lago de Tota (BoyacĂĄ). AsĂ­, se propusieron las posibles vĂ­as trĂłficas y el rol de cada especie en la red. En general, en la mayor parte de este estudio, las especies tuvieron un vĂ­nculo marcado con la vĂ­a autotrĂłfica, siendo el fitoplancton el recurso alimenticio base para la red trĂłfica, encontrando comĂșnmente señales empobrecidas de carbono. Particularmente, el anĂĄlisis mostrĂł una variaciĂłn en la fuente o recurso para dos especies (Daphnia laevis y Bosmina (Bosmina) cf. longirostris), con un enriquecimiento en su señal de 19.92‰ ÎŽ13C a -20.34‰ ÎŽ13C, lo que se puede dar por una plasticidad en su fuente alimenticia, e incluso el caso de Boeckella gracilis que tiene una señal que indica una especializaciĂłn en su recurso con valores empobrecidos de carbono -30 a -26‰ ÎŽ13C mientras que los valores de nitrĂłgeno son enriquecidos con un valor promedio de 20.21‰ en ÎŽ15N. Para establecer el fraccionamiento trĂłfico medio se formaron tres grupos, el primero (herbĂ­voros) conformado por (D. laevis, B. (Bosmina) cf. longirostris y Ceriodaphnia pulchella), el segundo (omnĂ­voro) en el que se encuentra (Daphnia pulex, Macrocyclops sp. y Cyclopoida), y un tercer grupo (Consumidor secundario) donde esta B. gracilis el Ășnico calanoido. En la comparaciĂłn de la variaciĂłn temporal, se observa que hay un cambio significativo en las señales de ÎŽ13C y ÎŽ15N de algunas especies en relaciĂłn a la influencia de las fuentes y su origen alĂłctono o autĂłctono, la variaciĂłn espacial no fue significativa. Se concluye que el macrozooplanton del lago de Tota, tiene un fuerte vĂ­nculo con la vĂ­a autotrĂłfica y que los niveles trĂłficos pelĂĄgicos tienen 3 eslabones, mĂĄs los productores primarios, y la red trĂłfica en general tiende a tener una amplitud del nicho trĂłfico.BibliografĂ­a: pĂĄginas 46-56.MaestrĂ­aMagĂ­ster en Ciencias BiolĂłgica

    Biological Convergence of Cancer Signatures

    Get PDF
    Gene expression profiling has identified cancer prognostic and predictive signatures with superior performance to conventional histopathological or clinical parameters. Consequently, signatures are being incorporated into clinical practice and will soon influence everyday decisions in oncology. However, the slight overlap in the gene identity between signatures for the same cancer type or condition raises questions about their biological and clinical implications. To clarify these issues, better understanding of the molecular properties and possible interactions underlying apparently dissimilar signatures is needed. Here, we evaluated whether the signatures of 24 independent studies are related at the genome, transcriptome or proteome levels. Significant associations were consistently observed across these molecular layers, which suggest the existence of a common cancer cell phenotype. Convergence on cell proliferation and death supports the pivotal involvement of these processes in prognosis, metastasis and treatment response. In addition, functional and molecular associations were identified with the immune response in different cancer types and conditions that complement the contribution of cell proliferation and death. Examination of additional, independent, cancer datasets corroborated our observations. This study proposes a comprehensive strategy for interpreting cancer signatures that reveals common design principles and systems-level properties

    The Microbiota Mediates Pathogen Clearance from the Gut Lumen after Non-Typhoidal Salmonella Diarrhea

    Get PDF
    Many enteropathogenic bacteria target the mammalian gut. The mechanisms protecting the host from infection are poorly understood. We have studied the protective functions of secretory antibodies (sIgA) and the microbiota, using a mouse model for S. typhimurium diarrhea. This pathogen is a common cause of diarrhea in humans world-wide. S. typhimurium (S. tmatt, sseD) causes a self-limiting gut infection in streptomycin-treated mice. After 40 days, all animals had overcome the disease, developed a sIgA response, and most had cleared the pathogen from the gut lumen. sIgA limited pathogen access to the mucosal surface and protected from gut inflammation in challenge infections. This protection was O-antigen specific, as demonstrated with pathogens lacking the S. typhimurium O-antigen (wbaP, S. enteritidis) and sIgA-deficient mice (TCRÎČ−/−ή−/−, JH−/−, IgA−/−, pIgR−/−). Surprisingly, sIgA-deficiency did not affect the kinetics of pathogen clearance from the gut lumen. Instead, this was mediated by the microbiota. This was confirmed using ‘L-mice’ which harbor a low complexity gut flora, lack colonization resistance and develop a normal sIgA response, but fail to clear S. tmatt from the gut lumen. In these mice, pathogen clearance was achieved by transferring a normal complex microbiota. Thus, besides colonization resistance ( = pathogen blockage by an intact microbiota), the microbiota mediates a second, novel protective function, i.e. pathogen clearance. Here, the normal microbiota re-grows from a state of depletion and disturbed composition and gradually clears even very high pathogen loads from the gut lumen, a site inaccessible to most “classical” immune effector mechanisms. In conclusion, sIgA and microbiota serve complementary protective functions. The microbiota confers colonization resistance and mediates pathogen clearance in primary infections, while sIgA protects from disease if the host re-encounters the same pathogen. This has implications for curing S. typhimurium diarrhea and for preventing transmission

    ICAR: endoscopic skull‐base surgery

    Get PDF
    n/
    • 

    corecore