227 research outputs found

    A review and meta-analysis of mitigation measures for nitrous oxide emissions from crop residues

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    Crop residues are of crucial importance to maintain or even increase soil carbon stocks and fertility, and thereby to address the global challenge of climate change mitigation. However, crop residues can also potentially stimulate emissions of the greenhouse gas nitrous oxide (N2_{2}O) from soils. A better understanding of how to mitigate N2_{2}O emissions due to crop residue management while promoting positive effects on soil carbon is needed to reconcile the opposing effects of crop residues on the greenhouse gas balance of agroecosystems. Here, we combine a literature review and a meta-analysis to identify and assess measures for mitigating N2_{2}O emissions due to crop residue application to agricultural fields. Our study shows that crop residue removal, shallow incorporation, incorporation of residues with C:N ratio > 30 and avoiding incorporation of residues from crops terminated at an immature physiological stage, are measures leading to significantly lower N2_{2}O emissions. Other practices such as incorporation timing and interactions with fertilisers are less conclusive. Several of the evaluated N2_{2}O mitigation measures implied negative side-effects on yield, soil organic carbon storage, nitrate leaching and/or ammonia volatilization. We identified additional strategies with potential to reduce crop residue N2_{2}O emissions without strong negative side-effects, which require further research. These are: a) treatment of crop residues before field application, e.g., conversion of residues into biochar or anaerobic digestate, b) co-application with nitrification inhibitors or N-immobilizing materials such as compost with a high C:N ratio, paper waste or sawdust, and c) use of residues obtained from crop mixtures. Our study provides a scientific basis to be developed over the coming years on how to increase the sustainability of agroecosystems though adequate crop residue management

    Maternal and Newborn Health in Karnataka State, India: The Community Level Interventions for Pre-Eclampsia (CLIP) Trial's Baseline Study Results.

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    Existing vital health statistics registries in India have been unable to provide reliable estimates of maternal and newborn mortality and morbidity, and region-specific health estimates are essential to the planning and monitoring of health interventions. This study was designed to assess baseline rates as the precursor to a community-based cluster randomized control trial (cRCT)-Community Level Interventions for Pre-eclampsia (CLIP) Trial (NCT01911494; CTRI/2014/01/004352). The objective was to describe baseline demographics and health outcomes prior to initiation of the CLIP trial and to improve knowledge of population-level health, in particular of maternal and neonatal outcomes related to hypertensive disorders of pregnancy, in northern districts the state of Karnataka, India. The prospective population-based survey was conducted in eight clusters in Belgaum and Bagalkot districts in Karnataka State from 2013-2014. Data collection was undertaken by adapting the Maternal and Newborn Health registry platform, developed by the Global Network for Women's and Child Health Studies. Descriptive statistics were completed using SAS and R. During the period of 2013-2014, prospective data was collected on 5,469 pregnant women with an average age of 23.2 (+/-3.3) years. Delivery outcomes were collected from 5,448 completed pregnancies. A majority of the women reported institutional deliveries (96.0%), largely attended by skilled birth attendants. The maternal mortality ratio of 103 (per 100,000 livebirths) was observed during this study, neonatal mortality ratio was 25 per 1,000 livebirths, and perinatal mortality ratio was 50 per 1,000 livebirths. Despite a high number of institutional deliveries, rates of stillbirth were 2.86%. Early enrollment and close follow-up and monitoring procedures established by the Maternal and Newborn Health registry allowed for negligible lost to follow-up. This population-level study provides regional rates of maternal and newborn health in Belgaum and Bagalkot in Karnataka over 2013-14. The mortality ratios and morbidity information can be used in planning interventions and monitoring indicators of effectiveness to inform policy and practice. Comprehensive regional epidemiologic data, such as that provided here, is essential to gauge improvements and challenges in maternal health, as well as track disparities found in rural areas

    Vulnerabilities and reparative strategies during pregnancy, childbirth, and the postpartum period:moving from rhetoric to action

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    Maternal outcomes throughout pregnancy, childbirth, and the postnatal period are influenced by interlinked and interdependent vulnerabilities. A comprehensive understanding of how various threats and barriers affect maternal and perinatal health is critical to plan, evaluate and improve maternal health programmes. This paper builds on the introductory paper of the Series on the determinants of maternal health by assessing vulnerabilities during pregnancy, childbirth, and the postnatal period. We synthesise and present the concept of vulnerability in pregnancy and childbirth, and map vulnerability attributes and their dynamic influence on maternal outcomes in early and late pregnancy and during childbirth and the postnatal period, with a particular focus on low-income and middle-income countries (LMICs). We summarise existing literature and present the evidence on the effects of various reparative strategies to improve pregnancy and childbirth outcomes. Lastly, we discuss the implications of the identified vulnerability attributes and reparative strategies for the efforts of policymakers, healthcare professionals, and researchers working towards improving outcomes for women and birthing people in LMICs

    Predicting field N2_{2}O emissions from crop residues based on their biochemical composition: A meta-analytical approach

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    Crop residue incorporation is a common practice to increase or restore organic matter stocks in agricultural soils. However, this practice often increases emissions of the powerful greenhouse gas nitrous oxide (N2_{2}O). Previous meta-analyses have linked various biochemical properties of crop residues to N2_{2}O emissions, but the relationships between these properties have been overlooked, hampering our ability to predict N2_{2}O emissions from specific residues. Here we combine comprehensive databases for N2_{2}O emissions from crop residues and crop residue biochemical characteristics with a random-meta-forest approach, to develop a predictive framework of crop residue effects on N2_{2}O emissions. On average, crop residue incorporation increased soil N2_{2}O emissions by 43% compared to residue removal, however crop residues led to both increases and reductions in N2_{2}O emissions. Crop residue effects on N2_{2}O emissions were best predicted by easily degradable fractions (i.e. water soluble carbon, soluble Van Soest fraction (NDS)), structural fractions and N returned with crop residues. The relationship between these biochemical properties and N2_{2}O emissions differed widely in terms of form and direction. However, due to the strong correlations among these properties, we were able to develop a simplified classification for crop residues based on the stage of physiological maturity of the plant at which the residue was generated. This maturity criteria provided the most robust and yet simple approach to categorize crop residues according to their potential to regulate N2_{2}O emissions. Immature residues (high water soluble carbon, soluble NDS and total N concentration, low relative cellulose, hemicellulose, lignin fractions, and low C:N ratio) strongly stimulated N2_{2}O emissions, whereas mature residues with opposite characteristics had marginal effects on N2_{2}O. The most important crop types belonging to the immature residue group – cover crops, grasslands and vegetables – are important for the delivery of multiple ecosystem services. Thus, these residues should be managed properly to avoid their potentially high N2_{2}O emissions

    No evidence for differential sociosexual behavior and space use in the color morphs of the European common wall lizard (Podarcis muralis)

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    Explaining the evolutionary origin and maintenance of color polymorphisms is a major challenge in evolutionary biology. Such polymorphisms are commonly thought to reflect the existence of alternative behavioral or life-history strategies under negative frequency-dependent selection. The European common wall lizardPodarcis muralisexhibits a striking ventral color polymorphism that has been intensely studied and is often assumed to reflect alternative reproductive strategies, similar to the iconic "rock-paper-scissors" system described in the North American lizardUta stansburiana. However, available studies so far have ignored central aspects in the behavioral ecology of this species that are crucial to assess the existence of alternative reproductive strategies. Here, we try to fill this gap by studying the social behavior, space use, and reproductive performance of lizards showing different color morphs, both in a free-ranging population from the eastern Pyrenees and in ten experimental mesocosm enclosures. In the natural population, we found no differences between morphs in site fidelity, space use, or male-female spatial overlap. Likewise, color morph was irrelevant to sociosexual behavior, space use, and reproductive success within experimental enclosures. Our results contradict the commonly held hypothesis thatP. muralismorphs reflect alternative behavioral strategies, and suggest that we should instead turn our attention to alternative functional explanations

    Increased placental expression of cannabinoid receptor 1 in preeclampsia

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    BackgroundThe endocannabinoid system plays a key role in female reproduction, including implantation, decidualization and placentation. In the present study, we aimed to analyze cannabinoid receptor 1 (CB1), CB2 and fatty acid amid hydrolase (FAAH) expressions and localization in normal and preeclamptic placenta, in order to determine whether placental endocannabinoid expression pattern differs between normal pregnancy and preeclampsia.MethodsEighteen preeclamptic patients and 18 normotensive, healthy pregnant women with uncomplicated pregnancies were involved in our case inverted question markcontrol study. We determined CB1, CB2 and FAAH expressions by Western blotting and immunohistochemistry in placental samples collected directly after Cesarean section.ResultsCB1 expression semi-quantified by Western blotting was significantly higher in preeclamptic placenta, and these findings were confirmed by immunohistochemistry. CB1 immunoreactivity was markedly stronger in syncytiotrophoblasts, the mesenchymal core, decidua, villous capillary endothelial and smooth muscle cells, as well as in the amnion in preeclamptic samples compared to normal pregnancies. However, we did not find significant differences between preeclamptic and normal placenta in terms of CB2 and FAAH expressions and immunoreactivity.ConclusionsWe observed markedly higher expression of CB1 protein in preeclamptic placental tissue. Increased CB1 expression might cause abnormal decidualization and impair trophoblast invasion, thus being involved in the pathogenesis of preeclampsia. Nevertheless, we did not find significant differences between preeclamptic and normal placental tissue regarding CB2 and FAAH expressions. While the detailed pathogenesis of preeclampsia is still unclear, the endocannabinoid system could play a role in the development of the disease

    Comparative descriptions of eggs from three species of Rhodnius (Hemiptera: Reduviidae: Triatominae)

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    The authors describe and compare the morphological and ultrastructural characteristics of eggs from the three most recent described species of the genus Rhodnius Stål, 1859, which have not previously been studied. These species are Rhodnius colombiensis (Mejia, Galvão & Jurberg 1999), Rhodnius milesi (Carcavallo, Rocha, Galvão & Jurberg 2001) and Rhodnius stali (Lent, Jurberg & Galvão 1993). The results revealed that there are similarities in the exochorial architecture of optical microscopy and scanning electron microscopy; these include the predominance of hexagonal cells that are common to all Rhodnius species and variable degrees of lateral flattening, which is common not only to species of this genus, but also to the Rhodniini tribe. Differences in overall colour, the presence of a collar in R. milesi, a longitudinal bevel in R. stali and the precise length of R. colombiensis can be useful distinguishing features. As a result of this study, the key for egg identification proposed by Barata in 1981 can be updated.European Community - Chagas Disease Intervention ActivitiesCNPqCoordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

    A microscopy-based screen employing multiplex genome sequencing identifies cargo-specific requirements for dynein velocity

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    The timely delivery of membranous organelles and macromolecules to specific locations within the majority of eukaryotic cells depends on microtubule-based transport. Here, we describe a screening method to identify mutations that have a critical effect on intracellular transport and its regulation using mutagenesis, multicolor-fluorescence microscopy, and multiplex genome sequencing. This screen exploits the filamentous fungus Aspergillus nidulans, which has many of the advantages of yeast molecular genetics, but uses long-range microtubule-based transport in a manner more similar to metazoan cells. Using this method, we identified 7 mutants that represent novel alleles of components of the intracellular transport machinery: specifically, kinesin-1, cytoplasmic dynein, and the dynein regulators Lis1 and dynactin. The two dynein mutations identified in our screen map to dynein's AAA+ catalytic core. Single-molecule studies reveal that both mutations reduce dynein's velocity in vitro. In vivo these mutants severely impair the distribution and velocity of endosomes, a known dynein cargo. In contrast, another dynein cargo, the nucleus, is positioned normally in these mutants. These results reveal that different dynein functions have distinct velocity requirements

    Novel Two-Component Systems Implied in Antibiotic Production in Streptomyces coelicolor

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    The abundance of two-component systems (TCSs) in Streptomyces coelicolor A3(2) genome indicates their importance in the physiology of this soil bacteria. Currently, several TCSs have been related to antibiotic regulation, and the purpose in this study was the characterization of five TCSs, selected by sequence homology with the well-known absA1A2 system, that could also be associated with this important process. Null mutants of the five TCSs were obtained and two mutants (ΔSCO1744/1745 and ΔSCO4596/4597/4598) showed significant differences in both antibiotic production and morphological differentiation, and have been renamed as abr (antibiotic regulator). No detectable changes in antibiotic production were found in the mutants in the systems that include the ORFs SCO3638/3639, SCO3640/3641 and SCO2165/2166 in any of the culture conditions assayed. The system SCO1744/1745 (AbrA1/A2) was involved in negative regulation of antibiotic production, and acted also as a negative regulator of the morphological differentiation. By contrast, the system SCO4596/4597/4598 (AbrC1/C2/C3), composed of two histidine kinases and one response regulator, had positive effects on both morphological development and antibiotic production. Microarray analyses of the ΔabrC1/C2/C3 and wild-type transcriptomes revealed downregulation of actII-ORF4 and cdaR genes, the actinorhodin and calcium-dependent antibiotic pathway-specific regulators respectively. These results demonstrated the involvement of these new two-component systems in antibiotic production and morphological differentiation by different approaches. One is a pleiotropic negative regulator: abrA1/A2. The other one is a positive regulator composed of three elements, two histidine kinases and one response regulator: abrC1/C2/C3
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