10 research outputs found

    Segregación estacional por sexo y edad de venado cola blanca en poblaciones de vida libre y encierro en Durango, México

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    White-tailed deer (Odocoileus virginianus) is a species with great economic and ecological relevance in Mexico, since it is the main game species in the country. Therefore, it is necessary to obtain reliable demographic data to improve its management. However, animal segregation movements could bias the population density estimations and demographic trends. This work aimed to analyse seasonal segregation by sex and age in free-living and fenced populations of white-tailed deer based on faecal groups. Fresh faecal groups of white-tailed deer were collected in two Wildlife Conservation Management Units (UMA in Spanish) located in Durango, Mexico: Salvador Allende and Molinillos. Faecal groups were collected every two weeks during 13 months for each UMA (from March 1st, 2015 to March 31st, 2016 for Salvador Allende, and from October 1st, 2015 to October 31st, 2016). The length and width of 10 faecal pellets were measured and the mean volume was calculated for each faecal group. Then, faecal groups were assigned to an age and sex category by a fuzzy set clustering technique. DNA was isolated from faecal pellets and a fragment of the SRY gene was amplified to determine the sex of the animals that deposited the faecal groups, in order to compare with the information obtained with the morphometric data of the pellets. The spatial-temporal data taken from faecal groups and the identification of age and sex were used for spatial sexual segregation coefficient (CSSE) calculation. Data about temperature, precipitation, photoperiod and vegetal cover were obtained for every season. A total of 351 fresh faecal groups were collected for both UMAs, in general, more faeces belonging to females. A lower number of faecal groups was collected in Salvador Allende (112). In both UMAs the lowest number of faecal groups was found in summer. The largest number of faecal groups was found in winter in Salvador Allende and in autumn in Molinillos. Statistic differences between segregation index between seasons was found. The sexual segregation index was higher in summer in both UMA (0.910 for Salvador Allende and 0.943 for Molinillos) when fawning occurred. By contrast, the lowest value was observed in winter (0.339) for Salvador Allende and in autumn (0.130) for Molinillos, when the breeding season occurred. Generally, reproductive behaviour determined age and sexual segregation. The highest proportion of faecal groups of juveniles was observed in spring and autumn in Salvador Allende and in summer in Molinillos. There was no correlation between sexual segregation index and environmental variables. It is necessary to consider variations in the segregation patterns in each season, since they can affect the population estimations based on the faecal counting technique. It is recommended to make the population estimates in seasons which spatial sexual segregation coefficient shows the highest and the lowest values.El venado cola blanca (Odocoileus virginianus) es una especie con valor económico, dado que es la especie cinegética más importante del país, por lo que es indispensable contar con datos confiables sobre su demografía para su mejor manejo. El objetivo de este trabajo fue analizar la segregación estacional por sexo y edad, a partir de grupos fecales, en dos grupos de venado cola blanca, uno en vida libre (UMA Salvador Allende, 3200 ha) y el otro en un encierro (UMA Molinillos, 300 ha) ubicados en el estado de Durango. Se colectaron grupos fecales para cada UMA cada dos semanas por 13 meses (del 1° de marzo 2015 al 31 de marzo 2016 en Salvador Allende y del 1° de octubre 2015 al 31 de octubre 2016 en Molinillos). Se midió el largo y ancho de 10 pellets fecales por grupo fecal y se calculó el volumen medio, para asignar los grupos fecales a una categoría de edad y sexo mediante la técnica de agrupamiento de conjuntos difusos (fuzzy sets). Se aisló ADN de los pellets fecales y se amplificó un fragmento del gen SRY para determinar el sexo de los animales que depositaron los grupos fecales y comparar con los resultados obtenidos de las medidas morfométricas de los pellets. Los datos espaciotemporales tomados de los grupos fecales, así como su identificación de edad y sexo, se utilizaron para calcular el grado de segregación sexual espacial (CSSE) en cada UMA. Se colectaron 351 grupos fecales frescos para ambas UMA durante todas las épocas del año, encontrando más grupos pertenecientes a hembras. En la población de vida libre se colectó un menor número de grupos fecales (112) que en la población en encierro (273). El grado de segregación espacial fue estadísticamente diferente entre épocas del año siendo mayores en verano en ambas UMA (0.910 para Salvador Allende y 0.943 en Molinillos) cuando ocurren los nacimientos. Los valores más bajos se presentaron en invierno (0.339) en Salvador Allende y en otoño (0.130) en Molinillos, cuando ocurre el celo, lo que indica que el CSSE estuvo regido por el comportamiento reproductivo. No se observó correlación entre el índice de segregación espacial y las variables ambientales. Hay que considerar las variaciones debidas a la segregación sexual y edad en cada época del año, ya que pueden afectar los resultados de estimaciones de población mediante la técnica de conteo de grupos fecales, dependiendo de la época en que se realicen, por lo que se recomienda llevar a cabo las estimaciones de población tanto en la época donde se presente el valor más alto de segregación sexual espacial, como en el más bajo para evitar sobreestimaciones

    Ants (Hymenoptera: Formicidae) of Durango, México.

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    Ants are eusocial insects of wide functional and taxonomic diversity, with worldwide distribution in various terrestrial ecosystems (some introduced by man), with the exception of the poles and in the high mountain peaks. About 15,947 species have been described. In Mexico, 973 are known within 94 genera, and for the state of Durango 60 species are registered within 25 genera. However, the Formicidae knowledge in Durango State is limited as it has received little attention; this is mainly due to the lack of specialists, as well as the territorial extension of it. In order to know the myrmecofauna of the state of Durango, collections were made every 15 days between August 1, 2016 and August 1, 2017, in 56 sites in 19 municipalities located in different ecoregions of the State. Forty (40) species belonging to 24 genera were collected; the Myrmicinae subfamily was the most diverse with 21 species, followed by Formicinae (12 spp.), Dolichoderinae (5 spp.) and Dorylinae and Ponerinae with one species each. Ten (10) more ant species are registered for the state of Durango, the richness increasing from 60 to 70 species and from 25 to 32 genera. This study represents the first effort to know the myrmecofauna of the state of Durango, Mexico

    Activity of Chloroformic Extract from <i>Salvia connivens</i> (Lamiales: Lamiaceae) and Its Principal Compounds against <i>Spodoptera frugiperda</i> (Lepidoptera: Noctuidae)

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    Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) is one of the most damaging pests in maize crops. In order to manage it, synthetic insecticides such as diamides, neonicotinoids, and pyrethroids are used, but they present a risk for humans and the environment. Investigations of safer alternatives include the use of natural extracts. Thus, this research evaluated the effects of chloroform extract (CHCl3Sc) (5000, 4000, 2000, 1000, and 500 ppm) on aerial parts of Salvia connivens and of nonanal and pyrocatechol (1000, 600, 400, and 80 ppm) on S. frugiperda mortality, duration of the larva and pupae phases, and pupae weight after 24 h. The second instars of S. frugiperda larvae were fed an artificial diet incorporating the extract and compounds. The CHCl3Sc had insecticidal activity against S. frugiperda, showing an LC50 of 1504 ppm. Insectistatic activity began at 1000 ppm, increasing pupal and larval duration in 7.6 and 1.4 days, respectively. Pyrocatechol and nonanal were found in this extract. The first did not have any significant difference in larval or pupal mortalities. On the other hand, insectistatic activity was shown at 500 ppm, increasing the larval duration by 1.7 days compared with the control. In the case of nonanal, the insecticide activity was LC50 of 200 ppm, and insectistatic activity started at 80 ppm, increasing larval duration by 3.2 days compared with the control and reducing pupal weight by 3.4%. The results show that chloroformic extract had insecticidal and insectistatic activities against S. frugiperda; nonanal was an aldehyde compound present in this extract, which confers insecticidal and insectistatic activities against this pest

    Mexico ants: incidence and abundance along the Nearctic–Neotropical interface

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    International audienceto explore different aspects of the population and community research of ants at different spatial scales, and to aid in the establishment of conservation policies and actions. There are no copyright restrictions. Please cite this data paper when using its data for publications or teaching events

    Mexico's Ants: Who are They and Where do They Live?

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    International audienc

    Association between convalescent plasma treatment and mortality in COVID-19: a collaborative systematic review and meta-analysis of randomized clinical trials

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    Abstract Background Convalescent plasma has been widely used to treat COVID-19 and is under investigation in numerous randomized clinical trials, but results are publicly available only for a small number of trials. The objective of this study was to assess the benefits of convalescent plasma treatment compared to placebo or no treatment and all-cause mortality in patients with COVID-19, using data from all available randomized clinical trials, including unpublished and ongoing trials (Open Science Framework, https://doi.org/10.17605/OSF.IO/GEHFX ). Methods In this collaborative systematic review and meta-analysis, clinical trial registries (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform), the Cochrane COVID-19 register, the LOVE database, and PubMed were searched until April 8, 2021. Investigators of trials registered by March 1, 2021, without published results were contacted via email. Eligible were ongoing, discontinued and completed randomized clinical trials that compared convalescent plasma with placebo or no treatment in COVID-19 patients, regardless of setting or treatment schedule. Aggregated mortality data were extracted from publications or provided by investigators of unpublished trials and combined using the Hartung–Knapp–Sidik–Jonkman random effects model. We investigated the contribution of unpublished trials to the overall evidence. Results A total of 16,477 patients were included in 33 trials (20 unpublished with 3190 patients, 13 published with 13,287 patients). 32 trials enrolled only hospitalized patients (including 3 with only intensive care unit patients). Risk of bias was low for 29/33 trials. Of 8495 patients who received convalescent plasma, 1997 died (23%), and of 7982 control patients, 1952 died (24%). The combined risk ratio for all-cause mortality was 0.97 (95% confidence interval: 0.92; 1.02) with between-study heterogeneity not beyond chance (I2 = 0%). The RECOVERY trial had 69.8% and the unpublished evidence 25.3% of the weight in the meta-analysis. Conclusions Convalescent plasma treatment of patients with COVID-19 did not reduce all-cause mortality. These results provide strong evidence that convalescent plasma treatment for patients with COVID-19 should not be used outside of randomized trials. Evidence synthesis from collaborations among trial investigators can inform both evidence generation and evidence application in patient care

    Association between convalescent plasma treatment and mortality in COVID-19: a collaborative systematic review and meta-analysis of randomized clinical trials

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    Abstract Background Convalescent plasma has been widely used to treat COVID-19 and is under investigation in numerous randomized clinical trials, but results are publicly available only for a small number of trials. The objective of this study was to assess the benefits of convalescent plasma treatment compared to placebo or no treatment and all-cause mortality in patients with COVID-19, using data from all available randomized clinical trials, including unpublished and ongoing trials (Open Science Framework, https://doi.org/10.17605/OSF.IO/GEHFX ). Methods In this collaborative systematic review and meta-analysis, clinical trial registries (ClinicalTrials.gov, WHO International Clinical Trials Registry Platform), the Cochrane COVID-19 register, the LOVE database, and PubMed were searched until April 8, 2021. Investigators of trials registered by March 1, 2021, without published results were contacted via email. Eligible were ongoing, discontinued and completed randomized clinical trials that compared convalescent plasma with placebo or no treatment in COVID-19 patients, regardless of setting or treatment schedule. Aggregated mortality data were extracted from publications or provided by investigators of unpublished trials and combined using the Hartung–Knapp–Sidik–Jonkman random effects model. We investigated the contribution of unpublished trials to the overall evidence. Results A total of 16,477 patients were included in 33 trials (20 unpublished with 3190 patients, 13 published with 13,287 patients). 32 trials enrolled only hospitalized patients (including 3 with only intensive care unit patients). Risk of bias was low for 29/33 trials. Of 8495 patients who received convalescent plasma, 1997 died (23%), and of 7982 control patients, 1952 died (24%). The combined risk ratio for all-cause mortality was 0.97 (95% confidence interval: 0.92; 1.02) with between-study heterogeneity not beyond chance (I2 = 0%). The RECOVERY trial had 69.8% and the unpublished evidence 25.3% of the weight in the meta-analysis. Conclusions Convalescent plasma treatment of patients with COVID-19 did not reduce all-cause mortality. These results provide strong evidence that convalescent plasma treatment for patients with COVID-19 should not be used outside of randomized trials. Evidence synthesis from collaborations among trial investigators can inform both evidence generation and evidence application in patient care
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