865 research outputs found

    What Are The Next Three Terms In This Sequence?

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    Continuing a sequence when the first three terms are provided is a problem that students encounter at many levels of instruction. Consider the following: 3, 6, 9, __, __, __.  When asked to fill in the blanks, many students (and more than a few teachers) mistakenly believe that there is only one correct answer. In the following article, the authors explore alternative solutions to such tasks, confirming that—in fact—such questions have many correct answers. Using a mix of by-hand and technology-based approaches, the authors explore three different types of sequences and show how to determine the explicit formula for each based on the term that is chosen next

    Dating the Cryptococcus gattii Dispersal to the North American Pacific Northwest.

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    The emergence of Cryptococcus gattii, previously regarded as a predominantly tropical pathogen, in the temperate climate of the North American Pacific Northwest (PNW) in 1999 prompted several questions. The most prevalent among these was the timing of the introduction of this pathogen to this novel environment. Here, we infer tip-dated timing estimates for the three clonal C. gattii populations observed in the PNW, VGIIa, VGIIb, and VGIIc, based on whole-genome sequencing of 134 C. gattii isolates and using Bayesian evolutionary analysis by sampling trees (BEAST). We estimated the nucleotide substitution rate for each lineage (1.59 × 10-8, 1.59 × 10-8, and 2.70 × 10-8, respectively) to be an order of magnitude higher than common neutral fungal mutation rates (2.0 × 10-9), indicating a microevolutionary rate (e.g., successive clonal generations in a laboratory) in comparison to a species' slower, macroevolutionary rate (e.g., when using fossil records). The clonal nature of the PNW C. gattii emergence over a narrow number of years would therefore possibly explain our higher mutation rates. Our results suggest that the mean time to most recent common ancestor for all three sublineages occurred within the last 60 to 100 years. While the cause of C. gattii dispersal to the PNW is still unclear, our research estimates that the arrival is neither ancient nor very recent (i.e., <25 years ago), making a strong case for an anthropogenic introduction. IMPORTANCE The recent emergence of the pathogenic fungus Cryptococcus gattii in the Pacific Northwest (PNW) resulted in numerous investigations into the epidemiological and enzootic impacts, as well as multiple genomic explorations of the three primary molecular subtypes of the fungus that were discovered. These studies lead to the general conclusion that the subtypes identified likely emerged out of Brazil. Here, we conducted genomic dating analyses to determine the ages of the various lineages seen in the PNW and propose hypothetical causes for the dispersal events. Bayesian evolutionary analysis strongly suggests that these independent fungal populations in the PNW are all 60 to 100 years old, providing a timing that is subsequent to the opening of the Panama Canal, which allowed for more direct shipping between Brazil and the western North American coastline, a possible driving event for these fungal translocation events

    Work‐Related Outcomes After a Myocardial Infarction

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90385/1/phco.24.16.1515.50946.pd

    Liver Parasites and Body Condition in Relation to Environmental Contaminants in Caribou (Rangifer tarandus) from Labrador, Canada

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    Over the last several decades, elders and hunters of the Innu Nation in Labrador, Canada, have expressed concerns over perceived declines in environmental health and the integrity of country food, including caribou. The primary objective of this study was to determine links between specific health parameters and contaminants found in caribou from the George River herd. Twenty-seven caribou killed by local Innu hunters between February and December 2001 were evaluated for gross and microscopic pathology, body condition, liver parasitology, and contaminant levels in kidney and fat. Overall, the sampled caribou appeared to be in adequate body condition for the time of year, and no clinically significant lesions were found. Concentrations of selenium, metals (Hg, Cd, and Pb), 20 organochlorine pesticides (HCB, a-HCH, g-HCH, aldrin, dieldrin, methoxychlor, mirex, a- and b-endosulfan, heptachlor, heptachlor epoxide, g-CHL, cis-CHL, trans-nonachlor, and o,p'- and p,p'-DDD, DDE, DDT), and 24 PCB congeners were within the ranges reported for caribou in Canada. In general, contaminant levels were relatively low, with the exception of cadmium in kidneys (geometric mean: 6.5 ÎŒg/g wet weight; range: 1.5–44.0 ÎŒg/g). Two types of liver parasites were found: the liver fluke Fascioloides magna (prevalence: 78%; geometric mean abundance: 4.2 flukes/caribou) and a tapeworm larva consistent with Taenia hydatigena (prevalence: 50%; geometric mean abundance: 0.6 larvae/caribou). Using multiple variable regression analysis, we found renal concentrations of cadmium to be positively associated, and selenium to be negatively associated, with F. magna abundance.Ces derniĂšres dĂ©cennies, les aĂźnĂ©s et les chasseurs de la nation montagnaise du Labrador, au Canada, ont exprimĂ© des inquiĂ©tudes au sujet du dĂ©clin de la santĂ© de l’environnement et de l’intĂ©gritĂ© de la nourriture provenant de la campagne, telle que le caribou. L’objectif principal de cette Ă©tude consistait Ă  dĂ©terminer les liens qui existent entre certains paramĂštres de santĂ© prĂ©cis et les contaminants se trouvant dans le caribou du troupeau de la riviĂšre George. Vingt-sept caribous ayant Ă©tĂ© tuĂ©s par les chasseurs montagnais de la rĂ©gion entre les mois de fĂ©vrier et de dĂ©cembre 2001 ont subi des examens pathologiques macroscopiques et microscopiques, en plus d’avoir Ă©tĂ© Ă©valuĂ©s pour en dĂ©terminer l’état du corps, la parasitologie du foie et les taux de contaminants dans le foie et le gras. Dans l’ensemble, l’état des corps de caribous Ă©chantillonnĂ©s semblait adĂ©quat pour cette pĂ©riode de l’annĂ©e et aucune lĂ©sion clinique importante n’a Ă©tĂ© signalĂ©e. Les concentrations de sĂ©lĂ©nium, de mĂ©taux (Hg, Cd et Pb), de 20 pesticides organochlorĂ©s (HCB, a-HCH, g-HCH, aldrine, dieldrine, mĂ©thoxychlore, mirex, a- et b-endosulfane, heptachlore, heptachlorĂ©poxyde, g-CHL, cis-CHL, trans-nonachlore ainsi que o,p'- et p,p'-DDD, DDE, DDT) et de 24 congĂ©nĂšres de PCB s’établissaient dans les Ă©tendues signalĂ©es pour le caribou au Canada. En gĂ©nĂ©ral, les niveaux de contaminants Ă©taient relativement faibles, Ă  l’exception du cadmium se trouvant dans les reins (moyenne gĂ©ometrique : 6,5 ÎŒg/g poids humide; Ă©tendue : 1,5–44,0 mg/g). Deux types de parasites du foie ont Ă©tĂ© trouvĂ©s : la douve Fascioloides magna (prĂ©valence : 78 %; abondance moyenne gĂ©omĂ©trique : 4,2 douves/caribou) et un cestode du genre Taenia hydatigena (prĂ©valence : 50 %; abondance moyenne gĂ©omĂ©trique : 0,6 larves/caribou). Nous avons Ă©galement rĂ©alisĂ© une analyse de rĂ©gression Ă  variables multiples qui nous a permis de constater que les concentrations de cadmium sont positivement associĂ©es et celles de sĂ©lĂ©nium sont nĂ©gativement associĂ©es Ă  l’abondance de F. magna

    Abstract Argumentation / Persuasion / Dynamics

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    The act of persuasion, a key component in rhetoric argumentation, may be viewed as a dynamics modifier. We extend Dung's frameworks with acts of persuasion among agents, and consider interactions among attack, persuasion and defence that have been largely unheeded so far. We characterise basic notions of admissibilities in this framework, and show a way of enriching them through, effectively, CTL (computation tree logic) encoding, which also permits importation of the theoretical results known to the logic into our argumentation frameworks. Our aim is to complement the growing interest in coordination of static and dynamic argumentation.Comment: Arisaka R., Satoh K. (2018) Abstract Argumentation / Persuasion / Dynamics. In: Miller T., Oren N., Sakurai Y., Noda I., Savarimuthu B., Cao Son T. (eds) PRIMA 2018: Principles and Practice of Multi-Agent Systems. PRIMA 2018. Lecture Notes in Computer Science, vol 11224. Springer, Cha
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