100 research outputs found

    Machine learning method for return direction forecasting of Exchange Traded Funds using classification and regression models

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    This article aims to propose and apply a machine learning method to analyze the direction of returns from Exchange Traded Funds (ETFs) using the historical return data of its components, helping to make investment strategy decisions through a trading algorithm. In methodological terms, regression and classification models were applied, using standard datasets from Brazilian and American markets, in addition to algorithmic error metrics. In terms of research results, they were analyzed and compared to those of the Na\"ive forecast and the returns obtained by the buy & hold technique in the same period of time. In terms of risk and return, the models mostly performed better than the control metrics, with emphasis on the linear regression model and the classification models by logistic regression, support vector machine (using the LinearSVC model), Gaussian Naive Bayes and K-Nearest Neighbors, where in certain datasets the returns exceeded by two times and the Sharpe ratio by up to four times those of the buy & hold control model.Comment: Co-author did not agree with publishing her

    Associations of indicators of sleep impairment and disorders with low muscle strength in middle-aged and older adults: The HypnoLaus cohort study.

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    Investigate associations of objective and subjective indicators of sleep impairment and disorders with low muscle strength (LMS) in different age groups and genders using data from a population-based cohort study. Polysomnographic and subjective sleep data from participants (aged 40-80 years) of the HypnoLaus study (Lausanne, Switzerland) were cross-sectionally analyzed. Indicators of sleep impairment and disorders were based on pre-defined cutoffs. LMS was defined according to the diagnosis of sarcopenia (grip strength <27 kg for men and <16 kg for women). Results obtained by multivariate logistic regression were controlled for confounders. 1902 participants (mean [SD] age, 57.4 [10.5] years; 968 [50.9 %] female) were enrolled. Objective short (<6.2 h) and long sleep durations (>8.5 h) were associated with LMS (OR = 1.74, 95 % CI = 1.07-2.82; OR = 6.66, 95 % CI = 3.45-12.87, respectively). Increased nighttime wakefulness >90 min and severe obstructive apnea (OSA) (AHI > 30) were associated with LMS (OR = 1.60, 95 % CI = 1.01-2.56; OR = 2.36, 95 % CI = 1.29-4.31, respectively). In adults aged over 60 years, these associations persisted, and reduced sleep efficiency was associated with LMS (aOR = 1.81, 95 % CI 1.05-3.13). Objective long sleep duration was associated with LMS in both genders and severe OSA predicted LMS among women (aOR = 2.64, 95 % CI 1.11-6.24). Markers of early sarcopenia are affected by long sleep duration from middle age onwards in both genders. Older adults are more susceptible to the effects of other indicators of inappropriate sleep duration and quality. The findings support a potential role of sarcopenia in age-related OSA. The intricate relationships between sleep and muscle health are potential targets of public health interventions and clinical research on preventive and therapeutic strategies against the increasing morbimortality observed with ageing

    Tapping into non-English-language science for the conservation of global biodiversity.

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    The widely held assumption that any important scientific information would be available in English underlies the underuse of non-English-language science across disciplines. However, non-English-language science is expected to bring unique and valuable scientific information, especially in disciplines where the evidence is patchy, and for emergent issues where synthesising available evidence is an urgent challenge. Yet such contribution of non-English-language science to scientific communities and the application of science is rarely quantified. Here, we show that non-English-language studies provide crucial evidence for informing global biodiversity conservation. By screening 419,679 peer-reviewed papers in 16 languages, we identified 1,234 non-English-language studies providing evidence on the effectiveness of biodiversity conservation interventions, compared to 4,412 English-language studies identified with the same criteria. Relevant non-English-language studies are being published at an increasing rate in 6 out of the 12 languages where there were a sufficient number of relevant studies. Incorporating non-English-language studies can expand the geographical coverage (i.e., the number of 2¬į √ó 2¬į grid cells with relevant studies) of English-language evidence by 12% to 25%, especially in biodiverse regions, and taxonomic coverage (i.e., the number of species covered by the relevant studies) by 5% to 32%, although they do tend to be based on less robust study designs. Our results show that synthesising non-English-language studies is key to overcoming the widespread lack of local, context-dependent evidence and facilitating evidence-based conservation globally. We urge wider disciplines to rigorously reassess the untapped potential of non-English-language science in informing decisions to address other global challenges. Please see the Supporting information files for Alternative Language Abstracts

    Simulating land use changes, sediment yields, and pesticide use in the Upper Paraguay River Basin: Implications for conservation of the Pantanal wetland

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    As a consequence of accelerated and excessive use of pesticides in tropical regions, wilderness areas are under threat; this includes the Pantanal wetlands in the Upper Paraguay River Basin (UPRB). Using a Land Cover Land Use Change (LCLUC) modelling approach, we estimated the expected pesticide load in the Pantanal and the surrounding highlands region for 2050 under three potential scenarios: i) business as usual (BAU), ii) acceleration of anthropogenic changes (ACC), and iii) use of buffer zones around protected areas (BPA). The quantity of pesticides used in the UPRB is predicted to vary depending on the scenario, from an overall increase by as much as 7.4% in the UPRB in the BAU scenario (increasing by 38.5% in the floodplain and 6.6% in the highlands), to an increase of 11.2% in the UPRB (over current use) under the AAC scenario (increasing by 53.8% in the floodplain and 7.5% in the highlands). Much higher usage of pesticides is predicted in sub-basins with greater agricultural areas within major hydrographic basins. Changing the current trajectory of land management in the UPRB is a complex challenge. It will require a substantial shift from current practices, and will involve the implementation of a number of strategies, ranging from the development of new technologies to achieve changes in land use policies, to increasing dialogue between farmers, ranchers, the scientific community, and local or traditional communities through participatory learning processes and outreach

    Tapping into non-English-language science for the conservation of global biodiversity

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    The widely held assumption that any important scientific information would be available in English underlies the underuse of non-English-language science across disciplines. However, non-English-language science is expected to bring unique and valuable scientific information, especially in disciplines where the evidence is patchy, and for emergent issues where synthesising available evidence is an urgent challenge. Yet such contribution of non- English-language science to scientific communities and the application of science is rarely quantified. Here, we show that non-English-language studies provide crucial evidence for informing global biodiversity conservation. By screening 419,679 peer-reviewed papers in 16 languages, we identified 1,234 non-English-language studies providing evidence on the effectiveness of biodiversity conservation interventions, compared to 4,412 English-language studies identified with the same criteria. Relevant non-English-language studies are being published at an increasing rate in 6 out of the 12 languages where there were a sufficient number of relevant studies. Incorporating non-English-language studies can expand the geographical coverage (i.e., the number of 2¬į √ó 2¬į grid cells with relevant studies) of English-language evidence by 12% to 25%, especially in biodiverse regions, and taxonomic coverage (i.e., the number of species covered by the relevant studies) by 5% to 32%, although they do tend to be based on less robust study designs. Our results show that synthesising non-English-language studies is key to overcoming the widespread lack of local, context-dependent evidence and facilitating evidence-based conservation globally. We urge wider disciplines to rigorously reassess the untapped potential of non-English-language science in informing decisions to address other global challenge

    Hunting practices of feral pigs (Sus scrofa) and predation by vampire bats (Desmodus rotundus) as a potential route of rabies in the Brazilian Pantanal.

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    Exotic species are known to cause an impact on native species and the environment through various ecological processes. Their impact on disease dynamics is not completely understood, but their relationship with the local fauna can favour the emergence of zoonoses. We reported records of predation of feral pigs (Sus scrofa) by common vampire bats (Desmodus rotundus) in the Brazilian Pantanal wetland and detailed how the traditional hunting, which involves castration management and hunting dogs, can represent a risk to emergency of rabies virus. With 1.43% of attack probability recorded by camera traps, we highlight the potential role of this interaction in disseminating zoonosis, especially in a scenario where hunting management has been prioritised as a policy tool in the control of exotic species. We alerted for the danger of rabies onset. Moreover, we suggested that the ranchers avoid contact with the pigs’ salivary secretions during hunting, to maintain up to date rabies vaccination on domestic animals, and pay attention to the clinical behaviours of rabies in their hunting dogs. Therefore, we must be aware of all the risks involved in interactions between humans and wildlife to reevaluate our practices and prevent viral outbreaks as we currently witness

    Beyond the HLA polymorphism: A complex pattern of genetic susceptibility to pemphigus

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    Habitat selection in natural and human-modified landscapes by capybaras (Hydrochoerus hydrochaeris), an important host for Amblyomma sculptum ticks.

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    Human activities are changing landscape structure and function globally, affecting wildlife space use, and ultimately increasing human-wildlife conflicts and zoonotic disease spread. Capybaras (Hydrochoerus hydrochaeris) are linked to conflicts in human-modified landscapes (e.g. crop damage, vehicle collision), as well as the spread and amplification of Brazilian spotted fever (BSF), the most human-lethal tick-borne disease in the world. Even though it is essential to understand the link between capybaras, ticks and BSF, many knowledge gaps still exist regarding the effects of human disturbance in capybara space use. Here, we analyzed diurnal and nocturnal habitat selection strategies of capybaras across natural and human-modified landscapes using resource selection functions (RSF). Selection for forested habitats was higher across human-modified landscapes, mainly during day- periods, when compared to natural landscapes. Across natural landscapes, capybaras avoided forests during both day- and night periods. Water was consistently selected across both landscapes, during day- and nighttime. Distance to water was also the most important variable in predicting capybara habitat selection across natural landscapes. Capybaras showed slightly higher preferences for areas near grasses/shrubs across natural landscapes, and distance to grasses/shrubs was the most important variable in predicting capybara habitat selection across human-modified landscapes. Our results demonstrate human-driven variation in habitat selection strategies by capybaras. This behavioral adjustment across human-modified landscapes may be related to increases in A. sculptum density, ultimately affecting BSF

    NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

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    Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data

    Camera trap feasibility for ecological studies of elusive forest deer.

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    The difficulty in observing and capturing elusive species in the wild is one of the main reasons for the limited number of studies on such species. This knowledge gap affects the development of conservation and management plans. Hence, testing the feasibility of research tools is essential for the future use and reliability of such tools. Camera traps increasingly are used as an alternative to capturing animals for wildlife research, and to generate important data for the management and conservation of many species. We identified individual free&#8208;ranging gray brocket deer (Mazama gouazoubira) from the Brazilian Pantanal by their natural markings. From October 2011 through September 2012, we investigated the feasibility of using camera traps for home range, habitat use, and activity period studies based on individuals with natural marks compared with the concurrent data collected from Global Positioning System (GPS) collars. Home range studies based on camera traps have limitations related to the quantity of individuals with natural marks and need for population premonitoring to detect them. The irregular performance of camera traps and lower detection probability in open habitats restricted its application in the habitat use study, especially among highly heterogeneous habitats. However, the positive correlation (r = 0.98, P < 0.001) between the frequency of photographic records and distances travelled by deer with GPS locations indicated reliable use of camera traps for research into activity periods. Camera traps can be used as an alternative to telemetry,potentially expanding the perspective and scope of noninvasive ecological studies for elusive and cryptic species
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