9,671 research outputs found
Is the transition redshift a new cosmological number?
Observations from Supernovae Type Ia (SNe Ia) provided strong evidence for an
expanding accelerating Universe at intermediate redshifts. This means that the
Universe underwent a transition from deceleration to acceleration phases at a
transition redshift of the order unity whose value in principle depends
on the cosmology as well as on the assumed gravitational theory. Since
cosmological accelerating models endowed with a transition redshift are
extremely degenerated, in principle, it is interesting to know whether the
value of itself can be observationally used as a new cosmic
discriminator. After a brief discussion of the potential dynamic role played by
the transition redshift, it is argued that future observations combining SNe
Ia, the line-of-sight (or "radial") baryon acoustic oscillations, the
differential age of galaxies, as well as the redshift drift of the spectral
lines may tightly constrain , thereby helping to narrow the parameter
space for the most realistic models describing the accelerating Universe.Comment: 12 pages, 5 figures. Some discussions about how to estimate the
transition redshift have been added. New data by Planck and H(z) data have
been mentioned. New references have been adde
New coupled quintessence cosmology
A component of dark energy has been recently proposed to explain the current
acceleration of the Universe. Unless some unknown symmetry in Nature prevents
or suppresses it, such a field may interact with the pressureless component of
dark matter, giving rise to the so-called models of coupled quintessence. In
this paper we propose a new cosmological scenario where radiation and baryons
are conserved, while the dark energy component is decaying into cold dark
matter (CDM). The dilution of CDM particles, attenuated with respect to the
usual scaling due to the interacting process, is characterized by a
positive parameter , whereas the dark energy satisfies the equation
of state (). We carry out a joint statistical
analysis involving recent observations from type Ia supernovae, baryon acoustic
oscillation peak, and Cosmic Microwave Background shift parameter to check the
observational viability of the coupled quintessence scenario here proposed.Comment: 7 pages, 7 figures. Minor corrections to match published versio
Budgetary balances adjustments from governmental accounting to national accounts in EU countries: can deficits be prone to management?
European Union (EU) countries are required to achieve deficit targets and are thus incentivized to use tools to keep within budgetary limits. This paper argues that accounting discretion might be used to manage some adjustments made during the translation of data from Governmental Accounting (GA) into National Accounts (NA), to window‐dress the final deficit/surplus reported to EUROSTAT. The empirical research shows there are certain circumstances that might facilitate the use of GA–NA “adjustment discretion.” EU authorities must pay special attention to these conditions to ensure the reliability of reported deficits. The main findings of this paper could also assist in future efforts to improve the integrity of the adjustment process.info:eu-repo/semantics/acceptedVersio
Levantamento do consumo de água para processamento da cana-de-açúcar na região de abrangência do Pólo Centro-Sul, Piracicaba, SP.
Resumo: A região de Piracicaba é tradicional produtora de cana-de-açúcar e na safra 2012/13 apresentou 327 mil hectares de área plantada. Os benefícios ambientais gerados com a eliminação da queima da cana para fins de colheita, também repercutem na diminuição do consumo de água pelas usinas. Com a introdução do novo sistema de colheita não é mais necessário, via de regra, o uso da água para a lavagem da cana-de-açúcar. No levantamento realizado para o Protocolo Agroambiental, feito nas usinas signatárias e com atividade na região de abrangência do Pólo Centro ? Sul da APTA, foi possível constatar que as 14 usinas desta região consomem em média 1,97 mm de água por tonelada de cana-de-açúcar. Esse trabalho apresenta os dados de precipitação pluviométrica da estação climatológica da Unidade de Pesquisa e Desenvolvimento ? UPD (antiga estação experimental de Tietê) da Agência Paulista de Tecnologia dos Agronegócios ? APTA, no período de 2009 a 2014
A Method for Obtaining Cosmological Models Consistency Relations and Gaussian Processes Testing
In the present work, we apply consistency relation tests to several
cosmological models, including the flat and non-flat CDM models, as
well as the flat XCDM model. The analysis uses a non-parametric Gaussian
Processes method to reconstruct various cosmological quantities of interest,
such as the Hubble parameter and its derivatives from data, as
well as the comoving distance and its derivatives from SNe Ia data. We
construct consistency relations from these quantities which should be valid
only in the context of each model and test them with the current data. We were
able to find a general method of constructing such consistency relations in the
context of reconstruction. In the case of comoving distance
reconstruction, there were not a general method of constructing such relations
and this work had to write an specific consistency relation for each model.
From data, we have analyzed consistency relations for all the three
above mentioned models, while for SNe Ia data we have analyzed consistency
relations only for flat and non-flat CDM models. Concerning the flat
CDM model, some inconsistency was found, at more than c.l.,
with the data in the interval , while the
other models were all consistent at this c.l. Concerning the SNe Ia data, the
flat CDM model was consistent in the interval, at
c.l., while the nonflat CDM model was consistent in the same interval,
at 2 c.l.Comment: 17 pages and 7 figure
Mecanização no cultivo de cana-de-açúcar como componente de sustentabilidade: o caso de Piracicaba/SP e Quirinópolis/GO.
Resumo: A mecanização dos sistemas produtivos de cana-de-açúcar tem sido intensa nos últimos anos devido às pressões da sociedade que buscam produtos com melhor qualidade e ecologicamente corretos. Do lado do produtor, existe também a busca por menores custos de produção na colheita. A expansão da cana-de-açúcar tem ocorrido de forma mais intensa nos estados do centro-oeste do Brasil, estes, por sua vez, têm apresentado altas taxas de mecanização graças à baixa declividade dos terrenos e ao alto investimento tecnológico. Esse trabalho tem por objetivo avaliar duas regiões de produção de cana: a região tradicional para produção de cana, Piracicaba/SP, e uma região de expansão, Quirinópolis/GO. Desse modo, estudar o funcionamento e características dos sistemas de produção de cana-de-açúcar no estado de São Paulo e as mudanças necessárias para os novos ambientes de produção pode ser a chave para entender com maior clareza as inovações eminentes para o setor e com isso definir instrumentos para apoiá-los de modo mais efetivo
Prospective impacts of sugarcane burning suppression: the agro-environmental contributions of the Green Protocol to sustainability.
Agricultural management practices assessment to improve the environmental and social impacts of sugarcane production system in São Paulo State.
Characterization of sugarcane production systems on São José do Rio Preto/São Paulo Mesoregion.
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