560 research outputs found
Raman Spectrum and Polarizability of Liquid Water from Deep Neural Networks
We introduce a scheme based on machine learning and deep neural networks to
model the environmental dependence of the electronic polarizability in
insulating materials. Application to liquid water shows that training the
network with a relatively small number of molecular configurations is
sufficient to predict the polarizability of arbitrary liquid configurations in
close agreement with ab initio density functional theory calculations. In
combination with a neural network representation of the interatomic potential
energy surface,the scheme allows us to calculate the Raman spectra along
2-nanosecond classical trajectories at different temperatures for H2O and D2O.
The vast gains in efficiency provided by the machine learning approach enable
longer trajectories and larger system sizes relative to ab initio methods,
reducing the statistical error and improving the resolution of the
low-frequency Raman spectra. Decomposing the spectra into intramolecular and
intermolecular contributions elucidates the mechanisms behind the temperature
dependence of the low-frequency and stretch modes
Ab initio theory and modeling of water
Water is of the utmost importance for life and technology. However, a
genuinely predictive ab initio model of water has eluded scientists. We
demonstrate that a fully ab initio approach, relying on the strongly
constrained and appropriately normed (SCAN) density functional, provides such a
description of water. SCAN accurately describes the balance among covalent
bonds, hydrogen bonds, and van der Waals interactions that dictates the
structure and dynamics of liquid water. Notably, SCAN captures the density
difference between water and ice I{\it h} at ambient conditions, as well as
many important structural, electronic, and dynamic properties of liquid water.
These successful predictions of the versatile SCAN functional open the gates to
study complex processes in aqueous phase chemistry and the interactions of
water with other materials in an efficient, accurate, and predictive, ab initio
manner
DIAGNÓSTICO E PLANO DE AÇÃO PARA A RECUPERAÇÃO DE NASCENTES DO RIO RANCHO MUNDO – CORBÉLIA – PR
A humanidade por séculos considerou inesgotável e renovável as fontes do recurso água. No entanto, nas últimas décadas, tornou se escasso, a tal modo, que segundo a Organização das Nações Unidas (ONU), 1,2 bilhões de pessoas, quase um quinto da população, encontram-se em áreas de escassez de água potável, enquanto 500 milhões, estão se aproximando dessa situação. Estudiosos afirmam que o motivo de próximos conflitos mundiais será por alimentos e água. O presente trabalho objetivou identificar fatores que interferem na qualidade da água das nascentes e desenvolver um plano de ação para minimização de problemas, que quantifique recursos financeiros e humanos, com base no diagnóstico das 72 nascentes da Microbacia do Rio Rancho Mundo - Corbélia - PR, no decorrer do período de novembro de 2010 a agosto de 2011. Avaliou-se a qualidade da água a partir da determinação de valores de coliformes fecais termotolerantes, pH, cor e turbidez presentes na água, obtidos por meio de análise laboratorial. Tais variáveis indicam a situação de uso e manejo de solo e de proteção de nascentes, a qual interfere na potabilidade da água. As intervenções nas áreas de APP devem ser realizadas em conjunto com as intervenções nas áreas adjacentes, as quais devem ser planejadas através de um plano de ação elaborado com base em dados e informações obtidas em um levantamento a campo
Multi year aerosol characterization in the tropical Andes and in adjacent Amazonia using AERONET measurements
This work focuses on the analysis of columnar aerosol properties in the complex geophysical tropical region of South America within 10-20 South and 50-70 West. The region is quite varied and encompasses a significant part of Amazonia (lowlands) as well as high mountains in the Andes (highlands,~4000 m a.s.l.). Several AERONET stations were included to study the aerosol optical characteristics of the lowlands (Rio Branco, Ji Parana and Cuiaba in Brazil and Santa Cruz in Bolivia) and the highlands (La Paz, Bolivia) during the 2000-2014 period. Biomass-burning is by far the most important source of aerosol in the lowlands, particularly during the dry season (August-October). Multi-annual variability was investigated and showed very strong burning activity in 2005, 2006, 2007 and 2010. This resulted in smoke characterized by correspondingly strong, above-average AODs (aerosol optical depths) and homogeneous single scattering albedo (SSA) across all the stations (~0.93). For other years, however, SSA differences arise between the northern stations (Rio Branco and Ji Parana) with SSAs of ~0.95 and the southern stations (Cuiaba and Santa Cruz) with lower SSAs of ~0.85.Such differences are explained by the different types of vegetation burned in the two different regions. In the highlands, however, the transport of biomass burning smoke is found to be sporadic in nature. This sporadicity results in highly variable indicators of aerosol load and type (Angstrom exponent and fine mode fraction) with moderately significant increases in both. Regional dust and local pollution are the background aerosol in this highland region, whose elevation places it close to the free troposphere. Transported smoke particles were generally found to be more optical absorbing than in the lowlands: the hypothesis to explain this is the significantly higher amount of water vapor in Amazonia relative to the high mountain areas. The air-mass transport to La Paz was investigated using the HYSPLIT air-concentration five-days back trajectories. Two different patterns were clearly differentiated: westerly winds from the Pacific that clean the atmosphere and easterly winds favoring the transport of particles from Amazonia.Marie Skłodowska-Curie Individual Fellowships (IF) ACE_GFAT (grant agreement No 659398).European Union's Horizon 2020 Research and Innovation Programme under grant agreement No. 654109, ACTRIS-2
Plants Probiotics as a Tool to Produce Highly Functional Fruits: The Case of Phyllobacterium and Vitamin C in Strawberries
10 páginas, 1 tabla, 1 figuraThe increasing interest in the preservation of the environment and the health of consumers
is changing production methods and food consumption habits. Functional foods are increasingly demanded by consumers because they contain bioactive compounds involved in health protection. In this sense biofertilization using plant probiotics is a reliable alternative to the use of chemical fertilizers, but there are few studies about the effects of plant probiotics on the yield of functional fruits and, especially, on the content of bioactive compounds. In the present work we reported that a strain of genus Phyllobacterium able to produce biofilms and to colonize strawberry roots is able to increase the yield and quality of strawberry plants. In addition, the fruits from plants inoculated with this strain have significantly higher content in vitamin C, one of the most interesting bioactive compounds in strawberries. Therefore the use of selected plant probiotics benefits the environment and human health without agronomical losses, allowing the production of highly functional foods.This work was granted by “Junta de Castilla y León” (Regional Government, Grant SA183A11-2) and MINECO (Central Government, Grant AGL2011-29227). Paula García-Fraile is
recipient of a postdoctoral researcher contract from
Academy of Sciences of the Czech Republic. José
David Flores-Félix was supported by a fellowship of
Salamanca University. Marta Marcos García was supported by a fellowship of Fundación Miguel Casado San José. Luís R. Silva is grateful to the financial support from the European Union (FEDER
funds through COMPETE) and National Funds (FCT,
Fundação para a Ciência e Tecnologia) through
project Pest-C/EQB/LA0006/2013 and from the
European Union (FEDER funds) under the framework
of QREN through Project NORTE-07-0124-FEDER-
000069.Peer reviewe
Histological evaluation on Brazilian green propolis effect in tissue repair of Wistar rats cutaneous wounds
This study aimed to evaluate the action of Brazilian green propolis (5%) topic use on cutaneous wound healing in rats, by inflammatory cell counting. Ten Wistar rats were separated in groups 24 h and 72 h, were trichotomized under anesthesia on cervical-dorsal region, and 2 wounds were provoked with a biopsy punch (5 mm diameter). Left wound underwent Brazilian green propolis topic treatment, and right wounds received nothing. Tissue samples were processed for light microscopy with hematoxilineosin., and leucocytes, macrophages and fibroblasts were counted using a histometric reticule in ocular lens. In both groups, within 24 and 72 h evolution, treated wounds demonstrated significant bigger means for leucocytes, macrophages and fibroblasts. Brazilian green propolis resulted in inflammatory cell quantity increase, suggesting its action on tissue repair process.Colegio de Farmacéuticos de la Provincia de Buenos Aire
Measuring nutritional knowledge using Item Response Theory and its validity in European adolescents
Objective: To analyse the Nutritional Knowledge Test (NKT) using Item Response Theory (ITR) analysis and to assess the construct validity of the Nutritional Knowledge Scale (NKTS) and its associations with adolescent food group consumption and nutritional biomarkers.
DesignCross-sectional study: SettingMulticentre investigation conducted in ten European cities.ParticipantsAdolescents aged 12·5-17·5 years (n 3215) who completed over 75 % of the NKT.
Results: Factor analysis indicated that the NKT can be analysed with a one-dimensional model. Eleven out of twenty-three items from the NKT presented adequate parameters and were selected to be included in the NKTS. Nutrition knowledge was positively associated with consumption of fruits, cereals, dairy products, pulses, meat and eggs, and fish, as well as with blood concentrations of vitamin C, ß-carotene, n-3 fatty acids, holo-transcobalamin, cobalamin and folate; nutrition knowledge was negatively associated with intake of olives and avocado, alcohol and savoury snacks.
Conclusions: The NKTS assessed nutritional knowledge adequately and it is proposed as a new tool to investigate this subject in future studies
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