Isothermal Variation Of The Entropy (Δ St) For The Compound Gd5 Ge4 Under Hydrostatic Pressure

In the present work, the isothermal variation of the entropy (Δ ST) for the compound Gd5 Ge4 was studied at different applied hydrostatic pressures (from 0 up to 0.58 GPa). In all pressure ranges, we observe the giant magnetocaloric effect. The Δ ST data for the compound Gd5 Ge4 at zero applied pressure present two peaks: the lowest temperature peak is due to irreversible processes and the highest temperature peak is due to magnetostructural transitions. Increasing the pressure, the lowest temperature peak displaces to lower temperatures and disappears. The magnitude of the other peak has a nonlinear behavior with pressure. Different protocols were used to obtain Δ ST at zero applied pressure and the results indicate that Δ ST strongly depends on the initial and final states of Gd5 Ge4 compound. We also present a T-P magnetic phase diagram built from the available magnetic data. © 2008 American Institute of Physics.1046Pecharsky, V.K., Gschneidner Jr., K.A., (1999) J. Magn. Magn. Mater., 200, p. 44. , 0304-8853 10.1016/S0304-8853(99)00397-2Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , (IOP, Bristol)Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 0031-9007 10.1103/PhysRevLett.78.4494Magen, C., Arnold, Z., Morellon, L., Skorokhod, Y., Algarabel, P.A., Ibarra, M.R., Kamarad, J., (2003) Phys. Rev. Lett., 91, p. 207202. , 0031-9007 10.1103/PhysRevLett.91.207202Levin, E.M., Gschneidner Jr., K.A., Pecharsky, V.K., (2002) Phys. Rev. B, 65, p. 214427. , 0163-1829 10.1103/PhysRevB.65.214427Levin, E.M., Pecharsky, V.K., Gschneidner Jr., K.A., Miller, G.J., (2001) Phys. Rev. B, 64, p. 235103. , 0163-1829 10.1103/PhysRevB.64.235103Tang, H., Pecharsky, V.K., Gschneidner Jr., K.A., (2004) Phys. Rev. B, 69, p. 064410. , 0163-1829 10.1103/PhysRevB.69.064410Chattopadhyay, M.K., Manekar, M.A., Pecharsky, A.O., Pecharsky, V.K., Gschneidner Jr., K.A., Moore, J., Perkins, G.K., Cohen, L.F., (2004) Phys. Rev. B, 70, p. 214421. , 0163-1829 10.1103/PhysRevB.70.214421Mudryk, Ya., Holm, A.P., Gschneidner Jr., K.A., Pecharsky, V.K., (2005) Phys. Rev. B, 72, p. 064442. , 0163-1829 10.1103/PhysRevB.72.064442Levin, E.M., Gschneidner Jr., K.A., Lograsso, T.A., Schlagel, D.L., Pecharsky, V.K., (2004) Phys. Rev. B, 69, p. 144428. , 0163-1829 10.1103/PhysRevB.69.144428Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Appl. Phys. Lett., 70, p. 3299. , 0003-6951 10.1063/1.119206Nikitin, S.A., Myalikgulyev, G., Tishin, A.M., Annaorazov, M.P., Asatryan, K.A., Tyurin, A.L., (1990) Phys. Lett. A, 148, p. 363. , 0375-9601 10.1016/0375-9601(90)90819-APecharsky, V.K., Gschneidner Jr., K.A., (1999) J. Appl. Phys., 86, p. 565. , 0021-8979 10.1063/1.370767Carvalho, A.M.G., (2006), Ph.D. thesis, UNICAMPCarvalho, A.M.G., Alves, C.S., De Campos, A., Coelho, A.A., Gama, S., Gandra, F.C.G., Von Ranke, P.J., De Oliveira, N.A., (2005) J. Appl. Phys., 97, pp. 10M320. , 0021-8979 10.1063/1.1860932Gschneidner Jr., K.A., Pecharsky, V.K., (2000) Annu. Rev. Mater. Sci., 30, p. 387. , 0084-6600 10.1146/annurev.matsci.30.1.387Carvalho, A.M.G., Alves, C.S., Colucci, C.C., Bolanho, M.A., Coelho, A.A., Gama, S., Nascimento, F.C., Cardoso, L.P., (2007) J. Alloys Compd., 432, p. 11. , 0925-8388 10.1016/j.jallcom.2006.05.121Wood, M.E., Potter, W.H., (1985) Cryogenics, 25, p. 667. , 0011-2275 10.1016/0011-2275(85)90187-0Magnus, A., Carvalho, G., Coelho, A.A., Gama, S., Von Ranke, P.J., De Oliveira, N.A., Da Silva, L.M., Gandra, F.C.G., (submitted

Composição química e atividade antimicrobiana do óleo essencial de folhas e flores de Aloysia gratissima

Volatile oils from leaves and flowers of Aloysia gratissima were investigated for their chemical composition and antimicrobial activity against the bacteria Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae and the Candida albicans yeast. The minimum inhibitory concentrations (MIC) of the oils were determined by the micro-dilution method, while the chemical composition was determined by GC-MS (gas chromatography mass spectrometry). The fresh leaves and inflorescence were subjected to hydrodistillation for 120 min using a Clevenger-type apparatus, and the essential oil was tested against microorganisms. High concentrations of sesquiterpenes were observed for the inflorescence, and monoterpenes were observed for the leaves. The main compounds of the inflorescence essential oil were E-caryophyllene, germacrene B, guaiol and bulnesol, while in the leaves the main compounds were trans-pinocamphone, trans-pinocarveyl acetate, and guaiol. The essential oil from the leaves showed an effect against P. aeruginosa and S. pneumonia, and the essential oil of the inflorescence showed an effect against P. aeruginosa, S. pneumonia, and Candida albicans.O óleo essencial de folhas e de flores de Aloysia gratissima foi avaliado quanto à composição química e ação antimicrobiana contra as bactérias Bacilus subtilis, Staphylococcus aureus, Salmonella choleraesuis, Pseudomonas aeruginosa, Streptococcus pneumoniae, e a levedura Candida albicans. A concentração mínima inibitória (MIC) dos óleos essenciais foi determinada pelo método da microdiluição e a composição química determinada por CG-EM (Cromatografia Gasosa acoplada a Espectrômetro de Massas). Folhas e inflorescências frescas foram hidrodestiladas por 120 minutos em aparelho Clevenger sendo o óleo essencial testado contra microorganismos. Para as flores foi observada maior concentração de sesquiterpenos, enquanto que as folhas apresentaram maior concentração de monoterpenos. Os principais constituintes do óleo essencial da flor foram: E-cariofileno, germacreno B, guaiol e bulnesol; e das folhas foram: trans-pinocamfona, acetato de trans-pinocarveol e guaiol. O óleo essencial da folha mostrou atividade contra P. aeruginosa e S. pneumoniae, e o óleo essencial da flor mostrou atividade contra P. aeruginosa, S. pneumoniae e Candida albicans.583588Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Evaluation of the AR4 CMIP3 and the AR5 CMIP5 model and projections for precipitation in northeast Brazil

This article compares the sensitivity of IPCC CMIP3-AR4 and CMIP5-AR5 models used on the latest reports from the Intergovernmental Panel on Climate Change (IPCC) in representing the annual average variations (austral summer and autumn) on three regions in Northeastern Brazil (NNEB) for the periods 1979–2000 using the CMAP (Climatology Merged Analysis of Precipitation) data as reference. The three areas of NNEB chosen for this analysis were the semiarid, eastern, and southern regions. The EOF analysis was performed to investigate how the coupled models resolve the temporal variability of the spatial modes in the Tropical Atlantic Sea Surface Temperature (SST), which drives the interannual variations of the rainfall in the Northeastern Brazil. CMIP3-AR4 and CMIP5-AR5 models presented a good representation of the annual cycle of precipitation. Results from correlation and mean absolute error analysis indicate that both CMIP3 and CMIP5 models produce large errors and barely capture the interannual rainfall variance during austral summer and autumn in Northeast Brazil, this features is closely related to the poor representation of the modes of SST variability in the Tropical Atlantic Ocean. For the summer and autumn rainfall projections (2040–2070) in the semiarid region, there was no convergence between the CMIP3 and CMIP5 models. During the summer and autumn in the eastern sector, both the CMIP3 and CMIP5 models projected rainfall above the mean for the 2040–2070 period

O epitélio respiratório em ratos Wistar após 48 horas de exposição contínua ao ruído de baixa frequência

ABSTRACTPrevious studies show that exposure to low frequency noise (LFN) (≤500Hz, including infrasound) produces irreversible lesions in Wistar rat respiratory epithelia. Recovery periods for LFN-induced lesions have thus become an object of interest. Changes in the respiratory epithelia of Wistar rats after continuous short-term exposure to LFN are described. Twelve rats were exposed to continuous LFN for 48hrs, and 10 age-matched rats were kept in silence. Animals were treated in accordance with 86/609/CE. After exposure ceased, two rodents were sacrificed immediately, and another two after 6, 12, 24, 48hrs, and 7 days of post-exposure silence. Respiratory epithelial fragments were prepared for light and scanning/ transmission electron microscopy. Six hours after exposure, intense and irregular cellular tumefaction was visible and rosetta structures, formed by secretory cells (SC) centered on a brush cell (BC), were identifiable. Cilia were shorter and shaggy. BC microvilli tended to group, losing the uniform distribution seen in controls. Twelve hours after exposure, cell balooning was still present, BC shape was highly irregular and microvilli were grouped. SC microvilli were still shorter than controls. Seven days after exposure, controls and exposed were indistinguishable. LFN-induced epithelial lesions seem to be reversible if recovery periods are respected.REV PORT PNEUMOL 2003; IX (6): 473-47

Effective Functional Form of Regge Trajectories

We present theoretical arguments and strong phenomenological evidence that hadronic Regge trajectories are essentially nonlinear and can be well approximated, for phenomenological purposes, by a specific square-root form.Comment: 29 pages, LaTeX. Published versio

An alternative order parameter for the 4-state Potts model

We have investigated the dynamic critical behavior of the two-dimensional 4-state Potts model using an alternative order parameter first used by Vanderzande [J. Phys. A: Math. Gen. \textbf{20}, L549 (1987)] in the study of the Z(5) model. We have estimated the global persistence exponent $\theta_g$ by following the time evolution of the probability $P(t)$ that the considered order parameter does not change its sign up to time $t$. We have also obtained the critical exponents $\theta$, $z$, $\nu$, and $\beta$ using this alternative definition of the order parameter and our results are in complete agreement with available values found in literature.Comment: 6 pages, 6 figure

Atomic Dark Matter

We propose that dark matter is dominantly comprised of atomic bound states. We build a simple model and map the parameter space that results in the early universe formation of hydrogen-like dark atoms. We find that atomic dark matter has interesting implications for cosmology as well as direct detection: Protohalo formation can be suppressed below $M_{proto} \sim 10^3 - 10^6 M_{\odot}$ for weak scale dark matter due to Ion-Radiation interactions in the dark sector. Moreover, weak-scale dark atoms can accommodate hyperfine splittings of order 100 \kev, consistent with the inelastic dark matter interpretation of the DAMA data while naturally evading direct detection bounds.Comment: 17 pages, 3 figure

Dark Matter Direct Detection with Non-Maxwellian Velocity Structure

The velocity distribution function of dark matter particles is expected to show significant departures from a Maxwell-Boltzmann distribution. This can have profound effects on the predicted dark matter - nucleon scattering rates in direct detection experiments, especially for dark matter models in which the scattering is sensitive to the high velocity tail of the distribution, such as inelastic dark matter (iDM) or light (few GeV) dark matter (LDM), and for experiments that require high energy recoil events, such as many directionally sensitive experiments. Here we determine the velocity distribution functions from two of the highest resolution numerical simulations of Galactic dark matter structure (Via Lactea II and GHALO), and study the effects for these scenarios. For directional detection, we find that the observed departures from Maxwell-Boltzmann increase the contrast of the signal and change the typical direction of incoming DM particles. For iDM, the expected signals at direct detection experiments are changed dramatically: the annual modulation can be enhanced by more than a factor two, and the relative rates of DAMA compared to CDMS can change by an order of magnitude, while those compared to CRESST can change by a factor of two. The spectrum of the signal can also change dramatically, with many features arising due to substructure. For LDM the spectral effects are smaller, but changes do arise that improve the compatibility with existing experiments. We find that the phase of the modulation can depend upon energy, which would help discriminate against background should it be found.Comment: 34 pages, 16 figures, submitted to JCAP. Tables of g(v_min), the integral of f(v)/v from v_min to infinity, derived from our simulations, are available for download at http://astro.berkeley.edu/~mqk/dmdd

Chemical composition and biological activities of Juçara (Euterpe edulis Martius) fruit by-products, a promising underexploited source of high-added value compounds

The pulp of the fruits of Juçara (Euterpes edulis Martius), a native tree of the Atlantic Rainforest of Brazil, is widely consumed thanks to its flavour and nutritional value. The industrial production of Juçara fruit pulp generates solid residues (peel) which are usually discarded. In this work, a hydroalcoholic extract from Juçara peel flour was evaluated for its phenolic profile as well as for its bioactivities. A total of nineteen phenolic compounds were identified in the Juçara peel flour. Among these, seventeen were non-anthocyanin phenolic compounds, namely two phenolic acids, four flavanonols, six flavones, and five flavonols; whereas the two anthocyanin molecules were cyanidin glycoside derivatives. The Euterpe edulis peel flour presented antioxidant activity and antibacterial potential but was not hepatotoxic. These observations corroborate the idea that this byproduct could fit well into the circular bioeconomy concept, thus promoting the Juçara fruit production chain.J.A.A. Garcia thanks Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for the financial support provided for her masters studies in the State University of Maringá. R.C.G. Corrêa thanks Conselho Nacional de Desenvolvimento Científico e Tecnologia (CNPq) for financing her postdoctoral research at State University of Maringá (Process number 167378/2017-1). R.M. Peralta (Project number 307944/2015-8) and A. Bracht (Project number 304090/2016-6) are CNPq research grant recipients. The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/ 00690/2013), L. Barros and R. C. Calhelha contracts; to FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E; the European Regional Development Fund (ERDF) to FEDER through the Regional Operational Program North 2020, within the scope of Project NORTE-01-0145-FEDER-023289: DeCodE and project Mobilizador Norte-01-0247-FEDER-024479: ValorNatural®.info:eu-repo/semantics/publishedVersio

Evaluation by blue native polyacrylamide electrophoresis colorimetric staining of the effects of physical exercise on the activities of mitochondrial complexes in rat muscle

Blue native polyacrylamide electrophoresis (BN-PAGE) is a technique developed for the analysis of membrane complexes. Combined with histochemical staining, it permits the analysis and quantification of the activities of mitochondrial oxidative phosphorylation enzymes using whole muscle homogenates, without the need to isolate muscle mitochondria. Mitochondrial complex activities were measured by emerging gels in a solution containing all specific substrates for NADH dehydrogenase and cytochrome c oxidase enzymes (complexes I and IV, respectively) and the colored bands obtained were measured by optique densitometry. The objective of the present study was the application of BN-PAGE colorimetric staining for enzymatic characterization of mitochondrial complexes I and IV in rat muscles with different morphological and biochemical properties. We also investigated these activities at different times after acute exercise of rat soleus muscle. Although having fewer mitochondria than oxidative muscles, white gastrocnemius muscle presented a significantly higher activity (26.7 ± 9.5) in terms of complex I/V ratio compared to the red gastrocnemius (3.8 ± 0.65, P < 0.05) and soleus (9.8 ± 0.9, P < 0.001) muscles. Furthermore, the complex IV/V ratio of white gastrocnemius muscle was always significantly higher when compared to the other muscles. Ninety-five minutes of exhaustive physical exercise induced a decrease in complex I/V and complex IV/V ratios after all resting times (0, 3 and 6 h) compared to control (P < 0.05), probably reflecting the oxidative damage due to increasing free radical production in mitochondria. These results demonstrate the possible and useful application of BN-PAGE-histochemical staining to physical exercise studies.93994