1,204 research outputs found

    Spheroidal and elliptical galaxy radial velocity dispersion determined from Cosmological General Relativity

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    Radial velocity dispersion in spheroidal and elliptical galaxies, as a function of radial distance from the center of the galaxy, has been derived from Cosmological Special Relativity. For velocity dispersions in the outer regions of spherical galaxies, the dynamical mass calculated for a galaxy using Carmelian theory may be 10 to 100 times less than that calculated from standard Newtonian physics. This means there is no need to include halo dark matter. The velocity dispersion is found to be approximately constant across the galaxy after falling from an initial high value at the center.Comment: 10 pages, 3 figure

    Dense ideal extensions of strict regular semigroups

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    If V is an existence variety of strict regular semigroups, then every semigroup in V has, within V, a maximal dense ideal extension

    A Contingent Valuation Study Of Buriti (mauritia Flexuosa L.f.) In The Main Region Of Production In Brazil: Is Environmental Conservation A Collective Responsibility?

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    Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)The immature leaves of the buriti palm (Mauritia flexuosa) are widely harvested in the municipality of Barreirinhas, Maranhão, for the production of handicrafts, which are sold to locals and tourists. The increasing demand for these artisanal goods is stimulating the emergence of an informal market for immature buriti leaves, leading to an intensification of their extraction and resulting in negative effects on local buriti palm populations and the ecosystem. Thus, the objective of the present study was to assess the environmental value of the buriti palm tree based on the maximum willingness to pay (WTP) for its conservation, using the contingent valuation method. Among the respondents, 99.74% reported that the palm species should be protected and the majority of them (65.75%) agreed to pay for its conservation (annual WTP R$ 179.49 ± 222.05). Multivariate analysis revealed that the WTP was not influenced by the socio-economic profile of the respondents. The main reasons for non-WTP are related to dissatisfaction with the government and the belief that financial contributions would not solve problems of environmental damage. Overall, the evaluated population believes that environmental conservation is not an obligation of the government or that of the population, but is a collective responsibility. © 2016, Sociedade Botanica do Brasil. All rights reserved.304532539CAPES, Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorMOE, Ministry of EducationCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    Finite bounded expanding white hole universe without dark matter

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    The solution of Einstein's field equations in Cosmological General Relativity (CGR), where the Galaxy is at the center of a finite yet bounded spherically symmetrical isotropic gravitational field, is identical with the unbounded solution. This leads to the conclusion that the Universe may be viewed as a finite expanding white hole. The fact that CGR has been successful in describing the distance modulus verses redshift data of the high-redshift type Ia supernovae means that the data cannot distinguish between unbounded models and those with finite bounded radii of at least cτc \tau. Also it is shown that the Universe is spatially flat at the current epoch and has been at all past epochs where it was matter dominated.Comment: 11 pages, revised versio

    Influence of ink rheology and post processing in the structural performance of silicon nitride-based ceramics fabricated by robocasting

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    The fabrication of complex shaped Si3N4 parts by conventional methods is challenging due to its high hardness and mechanical strength. Additive manufacturing (AM) appeared as a competitive way to attain three-dimensional complexity at lower costs. However, most of AM technologies still present limitations in producing high dense ceramics, mainly due to several difficulties in developing proper feedstock. This work presents the fabrication of dense silicon nitride-based ceramics by using an extrusion based additive manufacturing technique (direct ink writing, also known as robocasting) and cold isostatic pressing (CIP) as a post processing step. Silicon-nitride aqueous based inks containing different amounts of solids loading (36, 38 and 39 vol%) and proper rheological characteristics for the printing process were studied. The use of CIP (200 MPa) is suggested to reduce or even eliminate defects and porosity and consequently, to improve mechanical performance of the final parts. Relative density, microhardness and flexural strength increased as solids loading in the inks increased and were further improved when CIP pressing was used. Parts produced by robocasting with an ink containing 39 vol% and cold isostatic pressed at 200 MPa exhibited an average relative density around 99%, 1475 HV2 microhardness value and 650 MPa flexural strength, values similar to those of silicon nitride ceramics fabricated by conventional processing.publishe

    Effects Of External Fields On The Far-infrared 1s→2p+ Intradonor Absorption Spectra In Quantum Wells

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    The effects of both electric and magnetic fields (applied perpendicular to the interfaces) on the donor transition energies on a GaAs-Ga1-xAlxAs quantum well are studied by following a variational calculation within the effective-mass approximation with two-parameter variational envelope hydrogenic wave functions for the 1s- and 2p+-like donor states. A detailed analysis of the far-infrared intradonor absorption spectra, taking into account a proper consideration of the impurity-doping profile, is performed and results are compared with recent experimental data. The agreement between the reported magnetospectroscopic data and the average photon energy at the width at half-maximum of the calculated infrared-absorption spectra is quite apparent. It is unambiguously shown that the absorption spectra must be evaluated with an adequate choice of the variational envelope wave function for a correct quantitative understanding of the experimental measurements. © 1996 American Institute of Physics.80425362538Parihar, S.R., Lyon, S.A., (1993) Appl. Phys. Lett., 62, p. 2396Jarosik, N.C., McCombe, B.D., Shanabrook, B.V., Comas, J., Ralston, J., Wicks, G., (1985) Phys. Rev. Lett., 54, p. 1283Barmby, P.W., Dunn, J.L., Bates, C.A., (1994) J. Phys. Condens. Matter, 6, p. 751. , and references thereinChen, R., Cheng, J.P., Lin, D., McCombe, B.D., George, T.F., (1995) J. Phys. Condens. Matter, 7, p. 3577. , and references thereinLatgé, A., Porras-Montenegro, N., Oliveira, L.E., (1995) Phys. Rev. B, 51, p. 2259(1995) Phys. Rev. B, 51, p. 13344Latgé, A., Porras-Montenegro, N., De Dios-Leyva, M., Oliveira, L.E., (1996) Phys. Rev. B, 53, p. 10160Barbosa, L.H.M., Latgé, A., De Dios-Leyva, M., Oliveira, L.E., (1996) Solid State Commun., 98, p. 215Yoo, B.S., McCombe, B.D., Schaff, W., (1991) Phys. Rev. B, 44, p. 13152López-Gondar, J., D'Albuquerque E Castro, J., Oliveira, L.E., (1990) Phys. Rev. B, 42, p. 7069Greene, R.L., Bajaj, K.K., (1985) Phys. Rev. B, 31, p. 913(1986) Phys. Rev. B, 34, p. 951(1988) Phys. Rev. B, 37, p. 4604Chaudhuri, S., Bajaj, K.K., (1984) Solid State Commun., 52, p. 967(1984) Phys. Rev. B, 29, p. 1803Greene, R.L., Lane, P., (1986) Phys. Rev. B, 34, p. 8639(1986) Phys. Rev. B, 33, p. 587

    Does hepatocellular carcinoma in non-alcoholic steatohepatitis exist in cirrhotic and non-cirrhotic patients?

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    Non-alcoholic steatohepatitis (NASH) has been associated with hepatocellular carcinoma (HCC) often arising in histologically advanced disease when steatohepatitis is not active (cryptogenic cirrhosis). Our objective was to characterize patients with HCC and active, histologically defined steatohepatitis. Among 394 patients with HCC detected by ultrasound imaging over 8 years and staged by the Barcelona Clinic Liver Cancer (BCLC) criteria, we identified 7 cases (1.7%) with HCC occurring in the setting of active biopsy-proven NASH. All were negative for other liver diseases such as hepatitis C, hepatitis B, autoimmune hepatitis, Wilson disease, and hemochromatosis. The patients (4 males and 3 females, age 63 ± 13 years) were either overweight (4) or obese (3); 57% were diabetic and 28.5% had dyslipidemia. Cirrhosis was present in 6 of 7 patients, but 1 patient had well-differentiated HCC in the setting of NASH without cirrhosis (fibrosis stage 1) based on repeated liver biopsies, the absence of portal hypertension by clinical and radiographic evaluations and by direct surgical inspection. Among the cirrhotic patients, 71.4% were clinically staged as Child A and 14.2% as Child B. Tumor size ranged from 1.0 to 5.2 cm and 5 of 7 patients were classified as early stage; 46% of all nodules were hyper-echoic and 57% were <3 cm. HCC was well differentiated in 1/6 and moderately differentiated in 5/6. Alpha-fetoprotein was <100 ng/mL in all patients. HCC in patients with active steatohepatitis is often multifocal, may precede clinically advanced disease and occurs without diagnostic levels of alpha-fetoprotein. Importantly, HCC may occur in NASH in the absence of cirrhosis. More aggressive screening of NASH patients may be warranted
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