Organic management and soil health promote nutrient use efficiency

Introduction: Nitrogen is a key nutrient for plants. Often less than 50% of the applied nitrogen fertilisers is acquired by crops and nitrogen can be easily lost into the environment causing environmental pollution. Thus, to make agriculture more sustainable, it is important to investigate which factors determine nitrogen use efficiency (NUE). We investigated whether NUE was higher in organically managed soils compared to conventionally managed soils. Materials and Methods: To test this, we carried out a pot experiment in a greenhouse using soils from 16 fields. The soils were collected from conventionally (eight fields) or organically managed fields (eight fields). In addition, plants received two different 15N enriched N sources (mineral 15N or an organic fertiliser source, namely 15N enriched plant litter). Plants were harvested at three time points, and growth and nitrogen uptake were assessed at each time point. Results: NUE depended on management type and harvest time and the higher NUE of organically managed soils became more evident towards the second and third harvest. The average NUE at the end of the experiment was 93% and 55% for mineral fertiliser and litter application, respectively. This indicated that mineral fertilisers were immediately acquired by the plants, while nutrients in organic amendments had a lower availability and probably would be supplied later but steadier. Further, NUE was positively linked to microbial biomass, soil organic carbon content, and aggregate size, indicating that enhanced soil quality and soil health leads to a more efficient use of fertilisers. Conclusion: Our results indicate that organic management and soil health promote a more efficient use of nutrients and contribute to a more sustainable agriculture

One-dimensional thermal pressure-driven expansion of a pair cloud into an electron-proton plasma

Recently a filamentation instability was observed when a laser-generated pair cloud interacted with an ambient plasma. The magnetic field it drove was strong enough to magnetize and accelerate the ambient electrons. It is of interest to determine if and how pair cloud-driven instabilities can accelerate ions in the laboratory or in astrophysical plasma. For this purpose, the expansion of a localized pair cloud with the temperature 400 keV into a cooler ambient electron-proton plasma is studied by means of one-dimensional particle-in-cell (PIC) simulations. The cloud's expansion triggers the formation of electron phase space holes that accelerate some protons to MeV energies. Forthcoming lasers might provide the energy needed to create a cloud that can accelerate protons.Comment: 5 pages 4 figures, accepted for publication in Physics of Plasma

Luminosity- and morphology-dependent clustering of galaxies

How does the clustering of galaxies depend on their inner properties like morphological type and luminosity? We address this question in the mathematical framework of marked point processes and clarify the notion of luminosity and morphological segregation. A number of test quantities such as conditional mark-weighted two-point correlation functions are introduced. These descriptors allow for a scale-dependent analysis of luminosity and morphology segregation. Moreover, they break the degeneracy between an inhomogeneous fractal point set and actual present luminosity segregation. Using the Southern Sky Redshift Survey~2 (da Costa et al. 1998, SSRS2) we find both luminosity and morphological segregation at a high level of significance, confirming claims by previous works using these data (Benoist et al. 1996, Willmer et al. 1998). Specifically, the average luminosity and the fluctuations in the luminosity of pairs of galaxies are enhanced out to separations of 15Mpc/h. On scales smaller than 3Mpc/h the luminosities on galaxy pairs show a tight correlation. A comparison with the random-field model indicates that galaxy luminosities depend on the spatial distribution and galaxy-galaxy interactions. Early-type galaxies are also more strongly correlated, indicating morphological segregation. The galaxies in the PSCz catalog (Saunders et al. 2000) do not show significant luminosity segregation. This again illustrates that mainly early-type galaxies contribute to luminosity segregation. However, based on several independent investigations we show that the observed luminosity segregation can not be explained by the morphology-density relation alone.Comment: aastex, emulateapj5, 20 pages, 13 figures, several clarifying comments added, ApJ accepte

Endothelial dysfunction in neuroprogressive disorders—causes and suggested treatments

Background: Potential routes whereby systemic inflammation, oxidative stress and mitochondrial dysfunction may drive the development of endothelial dysfunction and atherosclerosis, even in an environment of low cholesterol, are examined. Main text: Key molecular players involved in the regulation of endothelial cell function are described, including PECAM-1, VE-cadherin, VEGFRs, SFK, Rho GEF TRIO, RAC-1, ITAM, SHP-2, MAPK/ERK, STAT-3, NF-κB, PI3K/AKT, eNOS, nitric oxide, miRNAs, KLF-4 and KLF-2. The key roles of platelet activation, xanthene oxidase and myeloperoxidase in the genesis of endothelial cell dysfunction and activation are detailed. The following roles of circulating reactive oxygen species (ROS), reactive nitrogen species and pro-inflammatory cytokines in the development of endothelial cell dysfunction are then described: paracrine signalling by circulating hydrogen peroxide, inhibition of eNOS and increased levels of mitochondrial ROS, including compromised mitochondrial dynamics, loss of calcium ion homeostasis and inactivation of SIRT-1-mediated signalling pathways. Next, loss of cellular redox homeostasis is considered, including further aspects of the roles of hydrogen peroxide signalling, the pathological consequences of elevated NF-κB, compromised S-nitrosylation and the development of hypernitrosylation and increased transcription of atherogenic miRNAs. These molecular aspects are then applied to neuroprogressive disorders by considering the following potential generators of endothelial dysfunction and activation in major depressive disorder, bipolar disorder and schizophrenia: NF-κB; platelet activation; atherogenic miRs; myeloperoxidase; xanthene oxidase and uric acid; and inflammation, oxidative stress, nitrosative stress and mitochondrial dysfunction. Conclusions: Finally, on the basis of the above molecular mechanisms, details are given of potential treatment options for mitigating endothelial cell dysfunction and activation in neuroprogressive disorders

Formation of Structure in Molecular Clouds: A Case Study

Molecular clouds (MCs) are highly structured and ``turbulent''. Colliding gas streams of atomic hydrogen have been suggested as a possible source of MCs, imprinting the filamentary structure as a consequence of dynamical and thermal instabilities. We present a 2D numerical analysis of MC formation via converging HI flows. Even with modest flow speeds and completely uniform inflows, non-linear density perturbations as possible precursors of MCs arise. Thus, we suggest that MCs are inevitably formed with substantial structure, e.g., strong density and velocity fluctuations, which provide the initial conditions for subsequent gravitational collapse and star formation in a variety of galactic and extragalactic environments.Comment: 4 pages, 5 figures, resubmitted to ApJ

Concerted Evaluation of Pesticides in Soils of Extensive Grassland Sites and Organic and Conventional Vegetable Fields Facilitates the Identification of Major Input Processes

The intensive use of pesticides and their subsequent distribution to the environment and non-target organisms is of increasing concern. So far, little is known about the occurrence of pesticides in soils of untreated areas─such as ecological refuges─as well as the processes contributing to this unwanted pesticide contamination. In this study, we analyzed the presence and abundance of 46 different pesticides in soils from extensively managed grassland sites, as well as organically and conventionally managed vegetable fields (60 fields in total). Pesticides were found in all soils, including the extensive grassland sites, demonstrating a widespread background contamination of soils with pesticides. The results suggest that after conversion from conventional to organic farming, the organic fields reach pesticide levels as low as those of grassland sites not until 20 years later. Furthermore, the different pesticide composition patterns in grassland sites and organically managed fields facilitated differentiation between long-term persistence of residues and diffuse contamination processes, that is, short-scale redistribution (spray drift) and long-scale dispersion (atmospheric deposition), to offsite contamination

Resultados de urocultivos en adultos realizados por el laboratorio de microbiología del Hospital de Clínicas - San Lorenzo de enero del 2015 a agosto de 2016 y métodos de estudio de las infecciones urinarias disponibles en la institución

Introducción: Los objetivos de este trabajo son: presentar los métodos de estudio de las infecciones urinarias actualmente disponibles en el Laboratorio de Microbiología del Hospital de Clínicas y mostrar los datos de los urocultivos evaluados en forma retrospectiva. Materiales y Métodos: Para estudiar los métodos de estudio de los urocultivos disponibles en el Laboratorio hemos recurrido al archivo del Laboratorio cuyos datos fueron consecutivamente cargados en una planilla de procesamiento de datos Excel de Microsoft Office ®. Los resultados de los urocultivos fueron evaluados de enero de 2015 a agosto de 2016, en forma retrospectiva, observacional, en corte transverso, de los adultos de ambos sexos. Las muestras para urocultivo son recibidas y procesadas en el laboratorio, siguiendo pasos preestablecidos. Resultados: El microorganismo preponderante de los urocultivos fue Escherichia coli (60% de las mujeres y 32% de los varones) seguido por Klebsiella pneumoniae (19% de los varones, 14% de las mujeres). Otros microorganismos aislados fueron Candida sp., Enterococcus faecalis, Enterobacter cloacae, Pseudomona aeruginosa, Proteus mirabilis, Staphylococcus aureus, Acinetobacter baumanii. La resistencia de Escherichia Coli a nitrofurantoína fue del 6% en los varones y 1% en las mujeres. La resistencia de E.Coli a meropenen fue también escasa. En cuanto a Klebsiella pneumoniae en las mujeres, la resistencia fue del 3%. En los hombres, los antibióticos testados para Klebsiella pneumoniae mostraron una resistencia superior al 30%, con excepción del meropenem. Uropatógenos productores de betalactamas de espectro extentido (BLEE) y de carbapenemasas fueron detectados en el presente estudio. Discusión: La toma de la orina para el urocultivo se efectúa siguiendo pautas claras, emanadas del laboratorio. Con la utilización de medios actualmente disponibles en el laboratorio, es posible tipificar el género y la especie tanto de bacterias Gram negativas y positivas como de hongos. Conclusión: La estructura del Laboratorio de Microbiología ha tenido avances que permiten la identificación precisa de los gérmenes de los urocultivos, así como la prevalencia y la resistencia que presentan a ciertos antibióticos. Estos aportes son particularmente útiles para los casos de Escherichia coli y Klebsiella pneumoniae debido a su alta prevalencia. También fue factible constatar la emergencia de gérmenes productores de betalactamasas de espectro extendido (BLEE) y carbapenemasas

Biologia de Ceratitis capitata (Diptera:Tephritidae) em variedades de uva de mesa cultivadas no Vale do São Francisco.

O objetivo do trabalho foi determinar qual o volume mínimo de dieta a ser colocado em copo plástico para a criação de Chloridea virescens (Fabricius)