Efeito dos sistemas de manejo e plantio sobre a densidade de grupos funcionais de microrganismos, em solo de cerrado.

O crescimento da agricultura e pecuária, que pode resultar em abertura de novas áreas de plantio, tem motivado pesquisas que buscam sistemas de produção mais sustentáveis, cujo manejo causa menor impacto e degradação do solo. O manejo do solo e a cobertura vegetal alteram suas propriedades, principalmente, as microbiológicas, provocando mudanças na densidade de microrganismos funcionais. O objetivo deste trabalho foi avaliar o efeito dos sistemas de manejo e dos diferentes sistemas de plantio, sobre a densidade de grupos funcionais de microrganismos em solos de Cerrado. As coletas de solo foram feitas em duas profundidades (0-5 cm e 5-20 cm) e dois períodos (seco e chuvoso), nos seguintes tratamentos: plantio direto (PD), plantio direto com rotação (PDR), plantio convencional (PC), plantio convencional com rotação (PCR) e Cerrado nativo (Mata mesofítica). A vegetação nativa apresentou as maiores densidades microbianas, nos períodos seco e chuvoso, em ambas as profundidades analisadas. Em geral, os tratamentos PDR e PD apresentaram maiores densidades microbianas nas camadas mais superficiais. Os dados de correlação linear (r) entre os grupos totais e funcionais de microrganismos e os atributos químicos do solo variaram entre os sistemas de preparo do solo. A correlação entre grupos funcionais de microrganismos e os atributos químicos do solo foram variáveis nos diferentes sistemas de manejo. Concluiu-se que o solo de cerrado apresentou maior densidade microbiana, não houve diferença na densidade microbiana entre os sistemas de preparo no período seco

Charge-transfer energy in iridates: A hard x-ray photoelectron spectroscopy study

We have investigated the electronic structure of iridates in the double perovskite crystal structure containing either Ir4+ or Ir5+ using hard x-ray photoelectron spectroscopy. The experimental valence band spectra can be well reproduced using tight-binding calculations including only the Ir 5d, O 2p, and O 2s orbitals with parameters based on the downfolding of the density-functional band structure results. We found that, regardless of the A and B cations, the A2BIrO6 iridates have essentially zero O 2p to Ir 5d charge-transfer energies. Hence double perovskite iridates turn out to be extremely covalent systems with the consequence being that the magnetic exchange interactions become very long ranged, thereby hampering the materialization of the long-sought Kitaev physics. Nevertheless, it still would be possible to realize a spin-liquid system using the iridates with a proper tuning of the various competing exchange interactions

Epidemiological and clinical features of rotavirus among children younger than 5 years of age hospitalized with acute gastroenteritis in Northern Italy

BACKGROUND: Rotavirus is the major cause of acute gastroenteritis and severe dehydrating diarrhea in young children. METHODS: To estimate the proportion of hospital admissions for rotavirus acute gastroenteritis and identify the circulating G and P genotypes among children under five years of age, we conducted a prospective observational study from January to December 2008, recruiting children consecutively admitted to six hospitals in Milan and nearby towns in northern Italy. Typing was done on stool samples by reverse transcriptase polymerase chain reaction amplification. RESULTS: Of the 521 stool samples from children with acute gastroenteritis, 34.9% (95%CI, 30.8 to 39.2%) were rotavirus-positive. Two thirds (67.6%) were under two years of age, and 13.2% were under six months. The predominant G type was G1 (40.7%), followed by G9 (22.5%), G2 (13.2%), G3 (5.5%), G4 (3.8%) and G10 (1.6%). Twenty-one (11.7%) mixed-G infections were identified: G1+G10 (8.8%); G1+G9 (1.6%); and G2+G10 (1.2%). Only P[8] (67.6%) and P[4] (12.6%) types were P genotyped. The predominant single G/P combination was G1P[8] (39.7%), followed by G9P[8] (25.3%), G2P[4] (14.3%), and G3P[8] (4.1%). All G-mixed types combined with P[8]. CONCLUSIONS: These findings show an high prevalence of rotavirus infections among children admitted to hospital for acute gastroenteritis caused by different rotavirus strains circulating in the area studied

Role of host genetics in fibrosis

Fibrosis can occur in tissues in response to a variety of stimuli. Following tissue injury, cells undergo transformation or activation from a quiescent to an activated state resulting in tissue remodelling. The fibrogenic process creates a tissue environment that allows inflammatory and matrix-producing cells to invade and proliferate. While this process is important for normal wound healing, chronicity can lead to impaired tissue structure and function

ANALOGUE SAMPLES IN AN EUROPEAN SAMPLE CURATION FACILITY - THE EURO-CARES PROJECT.

The objective of the H2020-funded EURO-CARES project (grant agreement n° 640190) was to create a roadmap for the implementation of a European Extraterrestrial Sample Curation Facility (ESCF) that would be suitable for the curation of samples from all possible return missions likely over the next few decades, i.e. from the Moon, asteroids and Mars. The return of extraterrestrial samples brought to Earth will require specific storage conditions and handling procedures, in particular for those coming from Mars. For practical reasons and sterility concerns it might be necessary for such a facility to have its own collection of analogue samples permitting the testing of storage conditions, and to develop protocols for sample prepartion and analyses. Within the framework of the EURO-CARES project, we havecreated a list of the different types of samples that would be relevant for such a curation facility. The facility will be used for receiving and opening of the returned sample canisters, as well as for handling and preparation of the returned samples. Furthermore, it will provide some analysis of the returned samples, i.e. early sample characterisation, and is expected to provide longterm storage of the returned samples. Each of these basic functions requires special equipment. Equipment, handling protocols and long-term storage conditions will strongly depend on the characteristics of the materials, and on whether returned samples are from the Moon, Mars or an asteroidal body. Therefore the different types and aspects of analogue samples one need to be considered, i.e. the nature of the materials, which analogues are needed for what purpose, what mass is needed, and how should the analogue samples be stored within the facility. We distinguished five different types of anologue samples: analogue (s.s.), witness plate, voucher specimen, reference sample, and standard. Analogues are materials that have one or more physical or chemical properties similar to Earth-returned extraterrestrial samples. Reference samples are well-characterised materials with known physical and chemical properties used for testing. They may not necessarily be the same materials as the analogues defined above. Standards are internationally recognised, homogeneous materials with known physical and chemical properties that are used for calibration. They can also be used as reference samples in certain circumstances. They may be made of natural materials but are often produced artificially. A voucher specimen is a duplicate of materials used at any stage during sample acquisition, storage, transport, treatment etc., e.g. spacecraft materials (including solar panels), lubricants, glues, gloves, saws, drills, and others. In addition, Earth landing site samples (from the touch down site) would be necessary in case of doubtful analysis, even if normally this type of contamination is not expected. Finally, a witness plate is defined as material left in an area where work is being done to detect any biological, particulate, chemical, and/or organic contamination. It is a spatial and temporal document of what happens in the work area. Analogue materials could be solids (including ices), liquids or gases. These could contain biological (extant and/or exinct) and/or organic components. They could be natural materials, e.g. rocks or minerals, or could be manufactured, such as mixtures of different components, which may be biologically and/or organically doped. Analogues with appropriate sample size and nature will be well-suited for testing and training of sample handling procedures, and for transport protocols. The training of science and curation teams also requires reference samples and standards. Long-term storage needs special witness plates and voucher specimes. Developing and testing sample preparation protocols needs all sample types

Anticipated Geological Assessment of the (65803) Didymos–Dimorphos System, Target of the DART–LICIACube Mission

On 2022 September 26, the DART spacecraft will impact the surface of Dimorphos, the ∼160 m size satellite of the binary near-Earth asteroid (NEA) (65803) Didymos. What will be observed on the surfaces of both asteroids and at the DART impact site is largely unknown, beyond the details of Didymos revealed by previous Arecibo and Goldstone radar observations. We present here the expected DART and LICIACube observations of the Didymos system and discuss the planned mapping strategies. By searching similar geological features and processes identified on other NEAs, we constrain the impact conditions that DART might encounter at Dimorphos, assessing both the asteroid's surface and interior structure

Reducing Bacterial Contamination in Fuel Ethanol Fermentations by Ozone Treatment of Uncooked Corn Mash

Ozonation of uncooked corn mash from the POET BPX process was investigated as a potential disinfection method for reducing bacterial contamination prior to ethanol fermentation. Corn mash (200 g) was prepared from POET ground corn and POET corn slurry and was ozonated in 250 mL polypropylene bottles. Lactic and acetic acid levels were monitored daily during the fermentation of ozonated, aerated, and nontreated corn mash samples to evaluate bacterial activity. Glycerol and ethanol contents of fermentation samples were checked daily to assess yeast activity. No yeast supplementation, no addition of other antimicrobial agents (such as antibiotics), and spiking with a common lactic acid bacterium found in corn ethanol plants,Lactobacillus plantarum, amplified the treatment effects. The laboratory-scale ozone dosages ranged from 26–188 mg/L, with very low estimated costs of $0.0008–0.006/gal ($0.21–1.6/m3) of ethanol. Ozonation was found to decrease the initial pH of ground corn mash samples, which could reduce the sulfuric acid required to adjust the pH prior to ethanol fermentation. Lactic and acetic acid levels tended to be lower for samples subjected to increasing ozone dosages, indicating less bacterial activity. The lower ozone dosages in the range applied achieved higher ethanol yields. Preliminary experiments on ozonating POET corn slurry at low ozone dosages were not as effective as using POET ground corn, possibly because corn slurry samples contained recycled antimicrobials from the backset. The data suggest additional dissolved and suspended organic materials from the backset consumed the ozone or shielded the bacteria.Reprinted with permission from J. Agric. Food Chem., 2015, 63 (21), pp 5239–5248. doi: 10.1021/acs.jafc.5b00563. Copyright 2015 American Chemical Society.</p