462 research outputs found

    Estimating mobility using sparse data: Application to human genetic variation.

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    Mobility is one of the most important processes shaping spatiotemporal patterns of variation in genetic, morphological, and cultural traits. However, current approaches for inferring past migration episodes in the fields of archaeology and population genetics lack either temporal resolution or formal quantification of the underlying mobility, are poorly suited to spatially and temporally sparsely sampled data, and permit only limited systematic comparison between different time periods or geographic regions. Here we present an estimator of past mobility that addresses these issues by explicitly linking trait differentiation in space and time. We demonstrate the efficacy of this estimator using spatiotemporally explicit simulations and apply it to a large set of ancient genomic data from Western Eurasia. We identify a sequence of changes in human mobility from the Late Pleistocene to the Iron Age. We find that mobility among European Holocene farmers was significantly higher than among European hunter-gatherers both pre- and postdating the Last Glacial Maximum. We also infer that this Holocene rise in mobility occurred in at least three distinct stages: the first centering on the well-known population expansion at the beginning of the Neolithic, and the second and third centering on the beginning of the Bronze Age and the late Iron Age, respectively. These findings suggest a strong link between technological change and human mobility in Holocene Western Eurasia and demonstrate the utility of this framework for exploring changes in mobility through space and time.L.L. was supported by Natural Environment Research Council, UK Grants NE/K005243/1 and NE/K003259/1 and European Research Council Grant 339941-ADAPT. M.G.T. was supported by Wellcome Trust Senior Investigator Award Grant 100719/Z/12/Z and Leverhulme Trust Grant RP2011-R-045. A.M. and A.E. were supported by European Research Council Consolidator Grant 647787-LocalAdaptation. M.M.L. was supported by European Research Council Advanced Grant 295907, In-Africa. M.K. was funded by the Engineering and Physical Sciences Research Council through the Centre for Mathematics and Physics in the Life Sciences and Experimental Biology

    Proximate drivers of spatial segregation in non-breeding albatrosses

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    Many animals partition resources to avoid competition, and in colonially-breeding species this often leads to divergent space or habitat use. During the non-breeding season, foraging constraints are relaxed, yet the patterns and drivers of segregation both between and within populations are poorly understood. We modelled habitat preference to examine how extrinsic (habitat availability and intra-specific competition) and intrinsic factors (population, sex and breeding outcome) influence the distributions of non-breeding grey-headed albatrosses Thalassarche chrysostoma tracked from two major populations, South Georgia (Atlantic Ocean) and the Prince Edward Islands (Indian Ocean). Spatial segregation was greater than expected, reflecting distinct seasonal differences in habitat selection and accessibility, and avoidance of intra-specific competition with local breeders. Previously failed birds segregated spatially from successful birds during summer, when they used less productive waters, suggesting a link between breeding outcome and subsequent habitat selection. In contrast, we found weak evidence of sexual segregation, which did not reflect a difference in habitat use. Our results indicate that the large-scale spatial structuring of albatross distributions results from interactions between extrinsic and intrinsic factors, with important implications for population dynamics. As habitat preferences differed substantially between colonies, populations should be considered independently when identifying critical areas for protectio

    Hypertensive emergency and type 2 myocardial infarction resulting from pheochromocytoma and concurrent capnocytophaga canimorsus infection

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    A diagnosis of myocardial infarction is made using a combination of clinical presentation, electrocardiogram and cardiac biomarkers. However, myocardial infarction can be caused by factors other than coronary artery plaque rupture and thrombosis. We describe an interesting case presenting with hypertensive emergency and type 2 myocardial infarction resulting from Pheochromocytoma associated with Capnocytophaga canimorsus infection from a dog bite. We also review current literature on the management of hypertensive emergency and Pheochromocytoma

    Deep history of cultural and linguistic evolution among Central African hunter-gatherers

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    Human evolutionary history in Central Africa reflects a deep history of population connectivity. However, Central African hunter-gatherers (CAHGs) currently speak languages acquired from their neighbouring farmers. Hence it remains unclear which aspects of CAHG cultural diversity results from long-term evolution preceding agriculture and which reflect borrowing from farmers. On the basis of musical instruments, foraging tools, specialized vocabulary and genome-wide data from ten CAHG populations, we reveal evidence of large-scale cultural interconnectivity among CAHGs before and after the Bantu expansion. We also show that the distribution of hunter-gatherer musical instruments correlates with the oldest genomic segments in our sample predating farming. Music-related words are widely shared between western and eastern groups and likely precede the borrowing of Bantu languages. In contrast, subsistence tools are less frequently exchanged and may result from adaptation to local ecologies. We conclude that CAHG material culture and specialized lexicon reflect a long evolutionary history in Central Africa

    Characterization of meloidogyne species from irrigated rice in southern Brazil.

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    Edição dos Proceedings do 6th International Congress of Nematology, Cape Town, South Africa, May 2014

    Spatial modes for transmission of chikungunya virus during a large chikungunya outbreak in Italy: a modeling analysis

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    14openInternationalBothBackground The spatial spread of many mosquito-borne diseases occurs by focal spread at the scale of a few hundred meters and over longer distances due to human mobility. The relative contributions of different spatial scales for transmission of chikungunya virus require definition to improve outbreak vector control recommendations. Methods We analyzed data from a large chikungunya outbreak mediated by the mosquito Aedes albopictus in the Lazio region, Italy, consisting of 414 reported human cases between June and November 2017. Using dates of symptom onset, geographic coordinates of residence, and information from epidemiological questionnaires, we reconstructed transmission chains related to that outbreak. Results Focal spread (within 1 km) accounted for 54.9% of all cases, 15.8% were transmitted at a local scale (1–15 km) and the remaining 29.3% were exported from the main areas of chikungunya circulation in Lazio to longer distances such as Rome and other geographical areas. Seventy percent of focal infections (corresponding to 38% of the total 414 cases) were transmitted within a distance of 200 m (the buffer distance adopted by the national guidelines for insecticide spraying). Two main epidemic clusters were identified, with a radius expanding at a rate of 300–600 m per month. The majority of exported cases resulted in either sporadic or no further transmission in the region. Conclusions Evidence suggest that human mobility contributes to seeding a relevant number of secondary cases and new foci of transmission over several kilometers. Reactive vector control based on current guidelines might allow a significant number of secondary clusters in untreated areas, especially if the outbreak is not detected early. Existing policies and guidelines for control during outbreaks should recommend the prioritization of preventive measures in neighboring territories with known mobility flows to the main areas of transmission.openGuzzetta, Giorgio; Vairo, Francesco; Mammone, Alessia; Lanini, Simone; Poletti, Piero; Manica, Mattia; Rosa, Roberto; Caputo, Beniamino; Solimini, Angelo; Torre, Alessandra Della; Scognamiglio, Paola; Zumla, Alimuddin; Ippolito, Giuseppe; Merler, StefanoGuzzetta, G.; Vairo, F.; Mammone, A.; Lanini, S.; Poletti, P.; Manica, M.; Rosa, R.; Caputo, B.; Solimini, A.; Torre, A.D.; Scognamiglio, P.; Zumla, A.; Ippolito, G.; Merler, S
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