Irreversible processes and the accelerated-decelerated phases of the Universe

A model for the Universe is proposed where it is considered as a mixture of scalar and matter fields. The particle production is due to an irreversible transfer of energy from the gravitational field to the matter field and represented by a non-equilibrium pressure. This model can simulate three distinct periods of the Universe: (a) an accelerated epoch where the energy density of the scalar field prevails over the matter field, (b) a past decelerated period where the energy density of the matter field becomes more predominant than the scalar energy density, and (c) a present acceleration phase where the scalar energy density overcomes the energy density of the matter field.Comment: 6 pages, 2 figures, to be published in Brazilian Journal of Physic

The critical success factors of GDPR implementation - a systematic literature review

Purpose: The digital paradigm people live in today, which drastically increased the consumption of data, is a threat to their privacy. To create a high level of privacy protection for its citizens, the European Union proposed the General Data Protection Regulation (GDPR), which introduces obligations for organizations regarding the storing, processing, collecting and disclosing of data. This paper aims to identify the critical success factors of GDPR implementation. Design/methodology/approach: A systematic literature review was conducted by following a strict review protocol, where 32 documents were found relevant to perform the review and to answer to the proposed research questions. Findings: The critical success factors of GDPR implementation were identified, including barriers and enablers. Furthermore, benefits of complying with GDPR were identified. Research limitations/implications: As GDPR is a relatively recent subject, there are still few scientific papers about it. Therefore, the authors were unable to neither identify nor present a robust conclusion regarding specific topics, such as practical outcomes. Originality/value: On the basis of the literature, the identified critical success factors may be useful for organizations as these can be better prepared to achieve compliance by prioritizing the enablers and avoiding the barriers.info:eu-repo/semantics/acceptedVersio

Os aningais: um tipo de vegetação "quase extinta nas cidades amazônicas".

Os aningais são compostos principalmente pela planta conhecida regionalmente como Aninga (Montrichardia arborescens Schott), uma Araceae que pode atingir 3 a 4 m de altura ocorrendo em densa sinúsia quase monoespecífica caracterizando a paisagem aningal. O objetivo desse trabalho é alertar para a destruição dos remanescentes de aningais nessas cidades e identificar as espécies que ocorre nessa região

Validação de plantio direto de soja sobre residuo de milheto.

Descrição dos agroecossistemas; Resultados; Rendimento de grãos; Rendimento financeiro.bitstream/item/36287/1/Doc36.pd

Water and nutrient flux measurements.

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Distribution of throughfall and stemflow in agroforestry, perennial monoculture, fallow and primary forest in the central Amazon, Brazil.

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Uso de ratos de laboratório para determinar o valor nutritivo do milho em diversos níveis de carunchamento.

Com o objetivo de avaliar os efeitos do milho carunchado e a qualidade de sua proteína para ratos em crescimento foi conduzido um experimento no biotério do Departamento de Nutrição/UFV. Trinta ratos (fêmeas) recém-desmamados, da linhagem Wistar, com 22 dias de idade e peso médio de 53,9 ± 3,2 g foram distribuídos em delineamento inteiramente casualizado para cinco tratamentos e seis repetições com um animal por unidade experimental. Os tratamentos consistiram de uma dieta basal (controle positivo), como um padrão de caseína, quatro dietas com milho que continha 2%; 10%; 17% e 38% de carunchamento e uma dieta isenta de proteína. O ensaio teve duração de 14 dias. Foram observados maior ganho de peso médio diário (GPMD), maior consumo de ração médio diário (CRMD), melhor conversão alimentar (CA) e maior razão protéica líquida (NPR) nos ratos que receberam a dieta padrão de caseína do que nas dietas que continham o milho carunchado, mas não foi observado diferença entre as dietas que continham diferentes níveis de carunchamento. Por outro lado, foi observado maiores coeficientes de digestibilidade de MS, PB e ED que na dieta padrão de caseína do que nas dietas contendo milho carunchado, embora maiores coeficientes tenham sido observados com 17% e que os valores semelhantes entre 2 e 38% provavelmente estejam relacionados ao processo de carunchamento. Com base nos dados do experimento, pode-se concluir que o aumento do nível de carunchamento do milho não afetou o desempenho dos animais e que a razão protéica líquida (NPR) do milho foi, em média, 57,8% do valor da dieta padrão de caseína. As variações observadas nos coeficientes de digestibilidade do milho podem ser atribuídos ao processo de carunchamento

Water and nutrient fluxes as indicators for the sustainability of different land-use systems on the terra firme near Manaus - a project overview.

Comparision of the water and nutrient fluxes in different perennial land-se systems, either monocultures or mixed cropping systems, in order to determine the resource efficiency of perennial land-se systems. They were comparision of the monocultue systems with Theobroma grandiflorum (cupuacu) or Bactris gasipaes (pupunha), polyculture systems with cupuacu, pupunh, Bixa orellana (urucum) and Bertholletia excelsa (castanha-do-Para) and primary and secondary forest sites. In the first experimental year, the equipment was installed to measure raianfall, throughfall, stemflow and soil water fluxes. These data combined with measurements of nutrient concentrations inform about the element fluxes. for this purpose, laboratory facilities were implemented to analyze anions and cations in the different land-se systems. Additionally, the nutrient and organic matter content of the soils were studied. Firt results showed that the investigated tree species differ in their effect on the water distribution and nutrient accumulation within the different cropping systems

Nutrient and water dynamics in a multi-strata agroforestry system.

In the presentel project, the nutriente and water fluxes are studied ann used as indicators for the stability of the agroforestry systems. The effects of the trees on soil properties, water and nutrient dynamics highly differed between species. To evaluate the sustaninability on an agroforestry system it is important to stress the consideration of spatial variability in the studied parameters. This variability creates the possibility to develop agroforestry with a complementary use of water and nutriente resources. The cropping sysytem with the current management is not seen as viable solution for land use in Amazonia at the moment. However, the discovered features of single trees and the effects on crop production and sustainability so far described encourage futher efforts to improve multi-strata agroforestry as a land use system for the Amazon region

Modified poly(heptazine imides) : minimizing H₂O₂ decomposition to maximize oxygen reduction

Photocatalysis provides a sustainable pathway to produce the consumer chemical H2O2 from atmospheric O2 via an oxygen reduction reaction (ORR). Such an alternative is attractive to replace the cumbersome traditional anthraquinone method for H2O2 synthesis on a large scale. Carbon nitrides have shown very interesting results as heterogeneous photocatalysts in ORR because their covalent two-dimensional (2D) structure is believed to increase selectivity toward the two-electron process. However, an efficient and scalable application of carbon nitrides for this reaction is far from being achieved. Poly(heptazine imides) (PHIs) are a more powerful subgroup of carbon nitrides whose structure provides high crystallinity and a scaffold to host transition-metal single atoms. Herein, we show that PHIs functionalized with sodium and the recently reported fully protonated PHI exhibit high activity in two-electron ORR under visible light. The latter converted O2 to up to 1556 mmol L–1 h–1 g–1 H2O2 under 410 nm irradiation using inexpensive but otherwise chemically demanding glycerin as a sacrificial electron donor. We also prove that functionalization with transition metals is not beneficial for H2O2 synthesis, as the metal also catalyzes its decomposition. Transient photoluminescence spectroscopy suggests that H-PHIs exhibit higher activity due to their longer excited-state lifetime. Overall, this work highlights the high photocatalytic activity of the rarely examined fully protonated PHI and represents a step forward in the application of inexpensive covalent materials for photocatalytic H2O2 synthesis