Biogas production by co-ensiling catch crops and straw, effect of substrate blend and microbial communities

The combination of catch crop (CC) and barley straw(S) for biogas production was investigated in order to evaluate the ensiling process in batch assay and in continuous process. Based on two new agriculture strategies designed to produce energy and improve nutrient cycling in organic farming are being evaluated, one of them consisting on the harvest of straw and catch crop in different periods whereas the other strategy consists on harvesting them at the same time. Catch crops is promoted to reduce nutrient leaching during rainy season and straw that is not used for animal feeding or bedding is generally left in the field. Mixtures of CC and S provides several advantages: 1) Provides adequate TS for silage, 2) Absorbs the silage effluent, 3) Produces high LAB activity, and 4) Provides an optimal C/N for anaerobic digestion (AD). The effect of feeding compositions (straw or manurea ddition) on the microbial community structures were also investigated

Previsão de dificuldade financeira em empresas de capital aberto

Several models for forecasting bankruptcy have been developed over the years, one of the reasons for which is the important part it plays in decision-making. However, forecasting a company’s bankruptcy leaves a very short time for stakeholders to change the situation. It is in this context that this paper arises in order to develop a model for predicting financial distress, which is identified as a step prior to bankruptcy. The predictive model uses the logistic regression technique with panel data and a sample of Brazilian publicly-traded companies with shares listed on the São Paulo Stock, Commodities, and Futures Exchange between 2001 and 2014. As well as financial variables, the final model includes market expectations (macroeconomic) and sector variables. These variables are statistically tested and the hypothesis is confirmed that they improve the accuracy of the model. The research identified the existence of financial distress in 96% of the companies that went bankrupt. In addition, the relationship between the phenomena of bankruptcy and financial distress is verified, using financial and macroeconomic explanatory variables. The results demonstrate that most (83%) of the explanatory variables in the model for predicting bankruptcy are also present in the model for predicting the phenomenon of financial distress. The expected gross domestic product variables and the quick ratio, asset turnover, and net equity over total liabilities financial variables are statistically significant in predicting both phenomena. With this evidence, the study suggests the use of the concept of financial distress as a stage prior to bankruptcy and provides a model for predicting financial distress with 89% accuracy when applied to publicly-traded companies in Brazil in the period examined.Ao longo dos anos, desenvolveram-se diversos modelos de previsão de insolvência, sendo uma das razões o seu importante papel na tomada de decisão. Entretanto, ao prever a insolvência de uma empresa, proporciona-se um tempo muito curto para que as partes interessadas consigam agir e reverter essa situação. É nesse contexto que o presente trabalho surge, com o objetivo de desenvolver um modelo de previsão de dificuldade financeira identificado como uma etapa anterior à insolvência. No desenvolvimento do modelo de previsão, utiliza-se a técnica de análise de regressão logística com dados em painel e a amostra de empresas brasileiras de capital aberto com ações negociadas na Bolsa de Valores, Mercadorias e Futuros de São Paulo, entre os períodos de 2001 e 2014. O modelo final contempla, além das variáveis financeiras, as variáveis de expectativa de mercado (macroeconômicas) e setorial. Essas variáveis são testadas estatisticamente e a hipótese de que melhoram a previsibilidade do modelo é confirmada. A pesquisa identificou a existência do estado de dificuldade financeira em 96% das empresas que entraram em insolvência. Além disso, verifica-se a relação entre os fenômenos de insolvência e dificuldade financeira. Os resultados obtidos demonstram que a maioria (83%) das variáveis explicativas do modelo de previsão de insolvência também está presente no modelo de previsão do fenômeno de dificuldade financeira. As variáveis de expectativa do produto interno bruto e as variáveis financeiras de liquidez seca, giro do ativo e patrimônio líquido sobre passivo total são estatisticamente significativas para prever ambos os fenômenos. Com esses indícios, o estudo sugere a utilização do conceito de dificuldade financeira como uma etapa predecessora da insolvência e disponibiliza um modelo de previsão de dificuldade financeira com poder de acerto de 89% dos casos, quando aplicado às empresas de capital aberto no Brasil no período pesquisado

Theoretical foundations of educational strategies used in e-learning environments for developing clinical reasoning in nursing students : a scoping review

E-learning environments expand opportunities for the use of educational strategies that may contribute to the development of clinical reasoning in nursing students. The purposes of this scoping review were the following: 1) to map the principles of cognitive companionship and the theoretical foundations underlying the design and implementation of educational strategies used in e-learning environments for developing clinical reasoning in nursing students; and 2) to identify the types of educational strategies used in e-learning environments for developing or assessing clinical reasoning in nursing students. A scoping review was conducted and was based on the Joanna Briggs Institute Framework. Bibliographical databases were searched for studies published between January 2010 to July 2017. Out of 1202 screened articles, 18 met eligibility criteria and were included in this review. Principles of cognitive companionship in e-learning environments provide key clues from a learning support perspective, such as integrated feedback, interactive group discussion, gaming, and questioning. However, theoretical foundations underlying educational strategies in e-learning environments are poorly documented and insufficiently associated with cognitive learning models. E-learning environments must have solid theoretical foundations to provide support for the development of CR in nursing students

The correlation between C/O ratio, metallicity and the initial WD mass for SNe Ia

In this paper, we want to check whether or not the carbon abundance can be affected by initial metallicity. We calculated a series of stellar evolution. We found that when $Z\leq0.02$, the carbon abundance is almost independent of metallicity if it is plotted against the initial WD mass. However, when $Z>0.02$, the carbon abundance is not only a function of the initial WD mass, but also metallicity, i.e. for a given initial WD mass, the higher the metallicity, the lower the carbon abundance. Based on some previous studies, i.e. both a high metallicity and a low carbon abundance lead to a lower production of $^{\rm 56}$Ni formed during SN Ia explosion, the effects of the carbon abundance and the metallicity on the amount of $^{\rm 56}$Ni are enhanced by each other, which may account for the variation of maximum luminosity of SNe Ia, at least qualitatively. Considering that the central density of WD before supernova explosion may also play a role on the production of $^{\rm 56}$Ni and the carbon abundance, the metallicity and the central density are all determined by the initial parameters of progenitor system, i.e. the initial WD mass, metallicity, orbital period and secondary mass, the amount of $^{\rm 56}$Ni might be a function of the initial parameters. Then, our results might construct a bridge linking the progenitor model and the explosion model of SNe Ia.Comment: 7pages, 4 figures, accepted for publication in A&

Horizontal DNA transfer mechanisms of bacteria as weapons of intragenomic conflict

Horizontal DNA transfer (HDT) is a pervasive mechanism of diversification in many microbial species, but its primary evolutionary role remains controversial. Much recent research has emphasised the adaptive benefit of acquiring novel DNA, but here we argue instead that intragenomic conflict provides a coherent framework for understanding the evolutionary origins of HDT. To test this hypothesis, we developed a mathematical model of a clonally descended bacterial population undergoing HDT through transmission of mobile genetic elements (MGEs) and genetic transformation. Including the known bias of transformation toward the acquisition of shorter alleles into the model suggested it could be an effective means of counteracting the spread of MGEs. Both constitutive and transient competence for transformation were found to provide an effective defence against parasitic MGEs; transient competence could also be effective at permitting the selective spread of MGEs conferring a benefit on their host bacterium. The coordination of transient competence with cell-cell killing, observed in multiple species, was found to result in synergistic blocking of MGE transmission through releasing genomic DNA for homologous recombination while simultaneously reducing horizontal MGE spread by lowering the local cell density. To evaluate the feasibility of the functions suggested by the modelling analysis, we analysed genomic data from longitudinal sampling of individuals carrying Streptococcus pneumoniae. This revealed the frequent within-host coexistence of clonally descended cells that differed in their MGE infection status, a necessary condition for the proposed mechanism to operate. Additionally, we found multiple examples of MGEs inhibiting transformation through integrative disruption of genes encoding the competence machinery across many species, providing evidence of an ongoing "arms race." Reduced rates of transformation have also been observed in cells infected by MGEs that reduce the concentration of extracellular DNA through secretion of DNases. Simulations predicted that either mechanism of limiting transformation would benefit individual MGEs, but also that this tactic's effectiveness was limited by competition with other MGEs coinfecting the same cell. A further observed behaviour we hypothesised to reduce elimination by transformation was MGE activation when cells become competent. Our model predicted that this response was effective at counteracting transformation independently of competing MGEs. Therefore, this framework is able to explain both common properties of MGEs, and the seemingly paradoxical bacterial behaviours of transformation and cell-cell killing within clonally related populations, as the consequences of intragenomic conflict between self-replicating chromosomes and parasitic MGEs. The antagonistic nature of the different mechanisms of HDT over short timescales means their contribution to bacterial evolution is likely to be substantially greater than previously appreciated

Formalizing the Ring of Witt Vectors

The ring of Witt vectors $\mathbb{W} R$ over a base ring $R$ is an important tool in algebraic number theory and lies at the foundations of modern $p$-adic Hodge theory. $\mathbb{W} R$ has the interesting property that it constructs a ring of characteristic $0$ out of a ring of characteristic $p > 1$, and it can be used more specifically to construct from a finite field containing $\mathbb{Z}/p\mathbb{Z}$ the corresponding unramified field extension of the $p$-adic numbers $\mathbb{Q}_p$ (which is unique up to isomorphism). We formalize the notion of a Witt vector in the Lean proof assistant, along with the corresponding ring operations and other algebraic structure. We prove in Lean that, for prime $p$, the ring of Witt vectors over $\mathbb{Z}/p\mathbb{Z}$ is isomorphic to the ring of $p$-adic integers $\mathbb{Z}_p$. In the process we develop idioms to cleanly handle calculations of identities between operations on the ring of Witt vectors. These calculations are intractable with a naive approach, and require a proof technique that is usually skimmed over in the informal literature. Our proofs resemble the informal arguments while being fully rigorous

PESCADOR, a web-based tool to assist text-mining of biointeractions extracted from PubMed queries

BACKGROUND: Biological function is greatly dependent on the interactions of proteins with other proteins and genes. Abstracts from the biomedical literature stored in the NCBI's PubMed database can be used for the derivation of interactions between genes and proteins by identifying the co-occurrences of their terms. Often, the amount of interactions obtained through such an approach is large and may mix processes occurring in different contexts. Current tools do not allow studying these data with a focus on concepts of relevance to a user, for example, interactions related to a disease or to a biological mechanism such as protein aggregation. RESULTS: To help the concept-oriented exploration of such data we developed PESCADOR, a web tool that extracts a network of interactions from a set of PubMed abstracts given by a user, and allows filtering the interaction network according to user-defined concepts. We illustrate its use in exploring protein aggregation in neurodegenerative disease and in the expansion of pathways associated to colon cancer. CONCLUSIONS: PESCADOR is a platform independent web resource available at: http://cbdm.mdc-berlin.de/tools/pescador

Ovine pedomics : the first study of the ovine foot 16S rRNA-based microbiome

We report the first study of the bacterial microbiome of ovine interdigital skin based on 16S rRNA by pyrosequencing and conventional cloning with Sanger-sequencing. Three flocks were selected, one a flock with no signs of footrot or interdigital dermatitis, a second flock with interdigital dermatitis alone and a third flock with both interdigital dermatitis and footrot. The sheep were classified as having either healthy interdigital skin (H), interdigital dermatitis (ID) or virulent footrot (VFR). The ovine interdigital skin bacterial community varied significantly by flock and clinical condition. The diversity and richness of operational taxonomic units was greater in tissue from sheep with ID than H or VFR affected sheep. Actinobacteria, Bacteriodetes, Firmicutes and Proteobacteria were the most abundant phyla comprising 25 genera. Peptostreptococcus, Corynebacterium and Staphylococcus were associated with H, ID and VFR respectively. Sequences of Dichelobacter nodosus, the causal agent of ovine footrot, were not amplified due to mismatches in the 16S rRNA universal forward primer (27F). A specific real time PCR assay was used to demonstrate the presence of D. nodosus which was detected in all samples including the flock with no signs of ID or VFR. Sheep with ID had significantly higher numbers of D. nodosus (104-109 cells/g tissue) than those with H or VFR feet

A Tale of Four Stories: Soil Ecology, Theory, Evolution and the Publication System

International audienceBACKGROUND: Soil ecology has produced a huge corpus of results on relations between soil organisms, ecosystem processes controlled by these organisms and links between belowground and aboveground processes. However, some soil scientists think that soil ecology is short of modelling and evolutionary approaches and has developed too independently from general ecology. We have tested quantitatively these hypotheses through a bibliographic study (about 23000 articles) comparing soil ecology journals, generalist ecology journals, evolutionary ecology journals and theoretical ecology journals. FINDINGS: We have shown that soil ecology is not well represented in generalist ecology journals and that soil ecologists poorly use modelling and evolutionary approaches. Moreover, the articles published by a typical soil ecology journal (Soil Biology and Biochemistry) are cited by and cite low percentages of articles published in generalist ecology journals, evolutionary ecology journals and theoretical ecology journals. CONCLUSION: This confirms our hypotheses and suggests that soil ecology would benefit from an effort towards modelling and evolutionary approaches. This effort should promote the building of a general conceptual framework for soil ecology and bridges between soil ecology and general ecology. We give some historical reasons for the parsimonious use of modelling and evolutionary approaches by soil ecologists. We finally suggest that a publication system that classifies journals according to their Impact Factors and their level of generality is probably inadequate to integrate "particularity" (empirical observations) and "generality" (general theories), which is the goal of all natural sciences. Such a system might also be particularly detrimental to the development of a science such as ecology that is intrinsically multidisciplinary

O PROCESSO DE FORMAÇÃO DE PREÇO DE UMA MICROEMPRESA DO SETOR TEXTIL DE CONFECÇÃO

No atual cenário econômico a formação do preço de venda de produtos e serviços tem sido vista com mais cautela entre os gestores, por se tratar de uma variável importantíssima para o sucesso de uma organização, fazendo com que as empresas se tornem prósperas e ativas no mercado. Diante da relevância do tema, bem como das dificuldades encontradas pelos gestores das microempresas para a correta apuração dos custos e formação de preços, esse trabalho se propõe a conhecer e analisar o processo de formação de preço de venda de uma microempresa do setor têxtil e de confecção do município de Porciúncula-RJ. Para esta análise, aplicou-se um questionário com perguntas relacionadas aos métodos que a empresa utiliza para precificar seus produtos, chegando-se então a conclusão de que o processo de formação de preços de venda da empresa utiliza-se de forma superficial dos fundamentos estabelecidos pelas Teorias contábil, econômica e de marketing