1,802 research outputs found
Rescuing Quartic and Natural Inflation in the Palatini Formalism
When considered in the Palatini formalism, the Starobinsky model does not
provide us with a mechanism for inflation due to the absence of a propagating
scalar degree of freedom. By (non)--minimally coupling scalar fields to the
Starobinsky model in the Palatini formalism we can in principle describe the
inflationary epoch. In this article, we focus on the minimally coupled quartic
and natural inflation models. Both theories are excluded in their simplest
realization since they predict values for the inflationary observables that are
outside the limits set by the Planck data. However, with the addition of the
term and the use of the Palatini formalism, we show that these models can
be rendered viable.Comment: JCAP accepted version, 16 pages, 7 figure
Low-complexity approximations for sets defined by generalizations of affine conditions
Let be a prime, let be a non-empty subset of and let
. We show that there exists a constant
such that for every positive integer , whenever are linear forms and
are subsets of , there exist linear forms and subsets of
such that the set is contained inside the set , and the difference has
density at most inside . We then generalize this result to one
where are replaced by homomorphisms for
some pair of finite Abelian groups and , and to another where they are
replaced by polynomial maps of small degree.Comment: 26 page
Recommended from our members
European Gas Markets, Trading Hubs, and Price Formation: A Network Perspective
We apply network theory to analyse the interactions of trading hub prices, and to assess the harmonisation of the European gas market. We construct dynamic networks, where the nodes correspond to the twelve EU trading hubs, and where the edges weight the causality between the variations of the respective gas prices. Network density dynamically calculates the aggregate quantity of causal interactions recorded within the system, which provides information pertaining to the integration of the European gas network. We document a number of spikes in network density, suggesting short periods of improved connectivity of European gas markets. We argue that these results appear to be driven by exogenous factors, such as unseasonal weather patterns, seismic activity and pipeline capacity reductions or outages. The findings elucidate the time varying nature of European gas market dynamics, and the importance of continual monitoring of market evolution
Seletividade de herbicidas e dinâmica populacional de plantas daninhas na cultura do girassol para a produção de biodiesel.
Os experimentos foram instalados em Prudente de Morais, MG, em 2010 e 2011, com o objetivo de avaliar a seletividade e a eficácia de herbicidas aplicados em pré e pósemergência na cultura do girassol, bem como de estudar a dinâmica populacional de plantas daninhas. O trabalho de 2010 foi conduzido em casa de vegetação em delineamento em blocos ao acaso com 11 tratamentos e três repetições. Os tratamentos foram constituÃdos por dez herbicidas, sendo quatro pré-emergentes e seis pós-emergentes (alachlor, imazaquin, metribuzin, trifluralin, chlorimuron-ethyl, fenoxaprop-p-ethyl, [fluazifop-p + fomesafen], imazapyr, imazethapyr e sethoxydim) e uma testemunha. Foram avaliados os efeitos fitotóxicos, altura das plantas, número de folhas e a biomassa seca da parte aérea e raÃzes aos 60 dias após a aplicação. Em 2011 o trabalho foi conduzido a campo, em delineamento de blocos ao acaso com seis tratamentos e quatro repetições. Os tratamentos consistiram dos herbicidas alachlor e trifluralin (préemergência), fenoxaprop-p-ethyl e sethoxydim (pós-emergência) e duas testemunhas (capinada e sem capina). Foram avaliados o ciclo da cultura, o inÃcio de florescimento, a altura de plantas, o diâmetro do caule, a maturação fisiológica dos aquênios, o diâmetro de capÃtulos, o número de plantas quebradas, o número de plantas acamadas, o estande final e o rendimento de aquênios. Com base nos resultados pode-se concluir que os herbicidas que apresentaram maior fitotoxicidade ao girassol foram: imazaquin, metribuzin, chlorimuron-ethyl, [fluazifop-p + fomesafen], imazapyr e imazethapyr. Os herbicidas pré-emergentes alachlor e trifluralin, e os pós-emergentes fenoxaprop-p-ethyl e sethoxydim mostraram-se seletivos para o girassol. O fenoxaprop-p-ethyl poderá vir a ser utilizado em um programa de manejo integrado de plantas daninhas no girassol, pois apenas trifluralin, alachlor e sethoxydim são herbicidas registrados para esta cultura
Culture\u27s influence on the perception of OCB as in-role or extra-role
The relationship between dimensions of individual level culture-related variables (social axioms) and the categorization of organizational citizenship behaviours (OCB) as in-role versus extra-role was explored within a Canadian sample. In order to appropriately address levels-of-analysis issues, this study focused on the relationship between two variables at the same level of analysis: individual social beliefs and individual perceptions of what constitutes OCB. Results indicate that the extent to which each of the OCB dimensions were viewed as in-role versus extra-role varied considerably among participants and that this variation could in part be predicted by social beliefs. The implications of understanding culture\u27s effect on employee work behaviours and attitudes are discussed
Polycystic Liver With Cardiac Compression Leading to Atrial Fibrillation: Case Report and Review of the Literature.
Polycystic liver disease (PCLD) is a rare condition that most often occurs in patients with polycystic kidney disease and less commonly as an isolated liver disease. Complications include cyst rupture, infection, hemorrhage, and compression of surrounding organs by large cysts. We present the case of a patient with a history of PCLD who presented to our hospital with palpitations and was found to have atrial fibrillation. Imaging and echocardiograph revealed a dominant large cyst compressing the right atrium. Other etiologies including thyroid disease, ischemic heart disease, and electrolytes abnormalities were excluded. The patient refused surgical intervention and was conservatively treated with rate control and anticoagulation. To the best of our knowledge, this is the first case of new-onset atrial fibrillation secondary to right atrial compression by a liver cyst. Compression of cardiac chambers resulting in new-onset arrhythmia should be considered when evaluating patients with PCLD
Levantamento fitossociológico de plantas daninhas em sorgo sacarino semeado em diferentes espaçamentos e densidades.
Edição dos Resumos do 1º Seminário de Agroecologia da América do Sul, 5º Seminário de Agroecologia de Mato Grosso do Sul, 4º Encontro de Produtores Agroecológicos de Mato Grosso do Sul, 1º Seminário de Sistemas Agroflorestais em Bases Agroecológicas de Mato Grosso do Sul, Dourados, nov. 2014
- …