Quintessence and tachyon dark energy models with a constant equation of state parameter

In this work we determine the correspondence between quintessence and tachyon dark energy models with a constant dark energy equation of state parameter, $w_e$. Although the evolution of both the Hubble parameter and the scalar field potential with redshift is the same, we show that the evolution of quintessence/tachyon scalar fields with redshift is, in general, very different. We explicity demonstrate that if $w_e \neq -1$ the potentials need to be very fine-tuned for the relative perturbation on the equation of state parameter, $\Delta w_e/(1+w_e) \ll 1$, to be very small around the present time. We also discuss possible implications of our results for the reconstruction of the evolution of $w_e$ with redshift using varying couplings.Comment: 9 pages, 2 figures, published version with two extra references include

Zastosowanie topiramatu w zapobieganiu migrenie przewlekłej

Przewlekła migrena (CM, chronic migraine) jest chorobą powodującą niesprawność, w której leczeniu stosuje się tylko nieliczne metody. Topiramat skutecznie zapobiega napadom migreny, jednak niewiele wiadomo o jego przydatności w CM. Przeprowadzono otwarte badanie z udziałem 64 chorych, u których rozpoznano lub wysunięto podejrzenie CM na podstawie kryteriów diagnostycznych ustalonych przez International Headache Society (IHS). U 50 chorych przeprowadzono analizę wyników zaplanowanego leczenia. Głównym punktem końcowym była liczba pacjentów, u których częstość bólu głowy zmniejszyła się o ponad 50%. Mediana stosowanej dawki leku wynosiła 100 mg na dobę; u 33 pacjentów (66%) częstość migreny zmniejszyła się o więcej niż 50%, a u 14 (28%) uzyskano pełną odpowiedź na leczenie, którą określono jako ograniczenie częstości bólów głowy o ponad 95%. Tolerancja leku była dobra. Do najczęstszych działań niepożądanych należały: utrata masy ciała, parestezje, nudności, zaburzenia czynności poznawczych, zmęczenie, senność, bezsenność i depresja. Wyniki badań wskazują na skuteczność topiramatu w profilaktyce CM

Nutritional, chemical and antioxidant/pro-oxidant profiles of silverskin, a coffee roasting by-product

Coffee silverskin (a coffee roasting by-product) contains high amounts of dietary fibre (49% insoluble and 7% soluble) and protein (19%). Potassium (∼5 g/100 g), magnesium (2 g/100 g) and calcium (0.6 g/100 g) are the major macrominerals. The vitamin E profile of silverskin comprises α-tocopherol, β-tocopherol, ɣ-tocopherol, δ-tocopherol, β-tocotrienol, ɣ-tocotrienol, and δ-tocotrienol. The fatty acid profile is mainly saturated (C16:0 and C22:0), but the total amount of fat is low (2.4%). Caffeine (1.25 g/100 g), chlorogenic acid (246 mg/100 g), and 5-hydroxymethylfurfural (5.68 mg/100 g) are also present in silverskin. Total phenolics and flavonoids are partially responsible for the in vitro antioxidant activity. Silverskin extracts protected erythrocytes from oxidative AAPH- and H2O2-induced hemolysis, but at high concentrations a pro-oxidant effect on erythrocyte morphology was observed.info:eu-repo/semantics/publishedVersio

Espaçamento para mandioca ( Manihot esculenta) em solos Fluminenses de baixa fertilidade

In four trials the spacing of 1.00, 1.20 and 1.40 m between rows and 0.50, 0.70 and 0.90 m between plants were studied in a randomized complete-block, split-plot design with 8 replicates in low fertility soils of three counties in the main cassava (Manihot esculenta Grantz) production area of the Rio de Janeiro State. It was concluded that there was no difference among spacing between rows for the total production of roots, independent of location, giving a yield of 15,400 kg/ha, approximately in all four trials. A 0.50 m spacing between plants produced the highest yield (16,184 kg/ha). The difference in production between the latter treatment and the other two was approximately 765 kg/ha. The roots were classified as commercial type (length from 0.20 to 0.40 m) and industrial type (0.30 to 0.50 m). The best spacing for both types of root was 1.40 m between rows which gave an increased production of 6.2% for the commercial type and 7.8% for the industrial type relative to the 1.00 m spacing. The best spacing between plants was 0.90 m which showed increased yield of 3.0 and 5.1% in comparison to 0.70 and 0.50 m respectively, for the commercial type. The increase in production for industrial type roots was 5.1 and 7.6% for the 0.90 m treatment in comparison to 0.70 and 0.50 in respectively.  Em quatro ensaios de campo, instalados em solos de baixa fertilidade de três municípios do Estado do Rio de Janeiro (Magé, São João da Barra e São Pedro da Aldeia), que integram a zona produtora de mandioca (Manihot esculenta Grantz) do Estado, foram estudados os espaçamentos de 1,00, 1,20 e 1,40 m entre fileiras e de 0,50, 0,70 e 0,90 m entre covas. O esquema experimental adotado foi o de parcelas subdivididas a partir de blocos ao acaso, com 8 repetições; o plantio foi feito em outubro (época das águas) e a colheita, 18 meses após. Numa análise conjunta dos quatro ensaios, verificou-se que para produção total de raízes, independente de localidade, não houve diferença entre os espaçamentos entre fileiras, que apresentaram produções médias em torno de 15.400 kg/ha. Para espaçamento entre covas, o que forneceu a mais alta produção (16.184 kg/ha), resultado significativo, foi o de 0,50 m, constatando-se que a produção caiu, em média, de 765 kg/ha para cada acréscimo de 20 cm no espaçamento. As raízes foram classificadas como comerciais (comprimento entre 0,20 e 0,40 m) e industriais (entre 0,30 e 0,50 m). Para ambos os tipos, o melhor espaçamento entre fileiras foi o de 1,40 m, que forneceu aumento de 6,2% para raízes tipo comercial, e 7,8% para raízes tipo industrial, relativamente ao espaçamento de 1 m. Dos espaçamentos entre covas, o melhor foi o de 0,90 m, que produziu 3,0 e 5,1% mais que os de 0,70 e 0,50 m, respectivamente, para o tipo comercial, e 5,1 e 7,6%, também respectivamente em relação aos mesmos espaçamentos, para o tipo industrial

Models of quintessence coupled to the electromagnetic field and the cosmological evolution of alpha

We study the change of the effective fine structure constant in the cosmological models of a scalar field with a non-vanishing coupling to the electromagnetic field. Combining cosmological data and terrestrial observations we place empirical constraints on the size of the possible coupling and explore a large class of models that exhibit tracking behavior. The change of the fine structure constant implied by the quasar absorption spectra together with the requirement of tracking behavior impose a lower bound of the size of this coupling. Furthermore, the transition to the quintessence regime implies a narrow window for this coupling around $10^{-5}$ in units of the inverse Planck mass. We also propose a non-minimal coupling between electromagnetism and quintessence which has the effect of leading only to changes of alpha determined from atomic physics phenomena, but leaving no observable consequences through nuclear physics effects. In doing so we are able to reconcile the claimed cosmological evidence for a changing fine structure constant with the tight constraints emerging from the Oklo natural nuclear reactor.Comment: 13 pages, 10 figures, RevTex, new references adde

Human toxocariasis: contribution by Brazilian researchers

In the present paper the main aspects of the natural history of human infection by Toxocara larvae that occasionally result in the occurrence of visceral and/or ocular larva migrans syndrome were reviewed. The contribution by Brazilian researchers was emphasized, especially the staff of the Tropical Medicine Institute of São Paulo (IMT)

Assessing the viability of successful reconstruction of the dynamics of dark energy using varying fundamental couplings

We assess the viability of successful reconstruction of the evolution of the dark energy equation of state using varying fundamental couplings, such as the fine structure constant or the proton-to-electron mass ratio. We show that the same evolution of the dark energy equation of state parameter with cosmic time may be associated with arbitrary variations of the fundamental couplings. Various examples of models with the same (different) background evolution and different (the same) time variation of fundamental couplings are studied in the letter. Although we demonstrate that, for a broad family of models, it is possible to redefine the scalar field in such a way that its dynamics is that of a standard quintessence scalar field, in general such redefinition leads to the breakdown of the linear relation between the scalar field and the variation of fundamental couplings. This implies that the assumption of a linear coupling is not sufficient to guarantee a successful reconstruction of the dark energy dynamics and consequently additional model dependent assumptions about the scalar field responsible for the dark energy need to be made.Comment: 7 pages, 2 figures, published versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters