Probing Yukawian gravitational potential by numerical simulations. I. Changing N-body codes

In the weak field limit general relativity reduces, as is well known, to the Newtonian gravitation. Alternative theories of gravity, however, do not necessarily reduce to Newtonian gravitation; some of them, for example, reduce to Yukawa-like potentials instead of the Newtonian potential. Since the Newtonian gravitation is largely used to model with success the structures of the universe, such as for example galaxies and clusters of galaxies, a way to probe and constrain alternative theories, in the weak field limit, is to apply them to model the structures of the universe. In the present study, we consider how to probe Yukawa-like potentials using N-body numerical simulations.Comment: 17 pages, 11 figures. To appear in General Relativity and Gravitatio

c-Fos expression induced by electroacupuncture at the Zusanli point in rats submitted to repeated immobilization

In laboratory animals, acupuncture needs to be performed on either anesthetized or, if unanesthetized, restrained subjects. Both procedures up-regulate c-Fos expression in several areas of the central nervous system, representing therefore a major pitfall for the assessment of c-Fos expression induced by electroacupuncture. Thus, in order to reduce the effect of acute restraint we used a protocol of repeated restraint for the assessment of the brain areas activated by electroacupuncture in adult male Wistar rats weighing 180-230 g. Repeated immobilization protocols (6 days, 1 h/day and 13 days, 2 h/day) were used to reduce the effect of acute immobilization stress on the c-Fos expression induced by electroacupuncture at the Zusanli point (EA36S). Animals submitted to immobilization alone or to electroacupuncture (100 Hz, 2-4 V, faradic wave) in a non-point region were compared to animals submitted to electroacupuncture at EA36S (4 animals/subgroup). c-Fos expression was measured in 41 brain areas by simple counting of cells and the results are reported as number of c-Fos-immunoreactive cells/10,000 µm². The protocols of repeated immobilization significantly reduced the immobilization-induced c-Fos expression in most of the brain areas analyzed (P < 0.05). Animals of the EA36S groups had significantly higher levels of c-Fos expression in the dorsal raphe nucleus, locus coeruleus, posterior hypothalamus and central medial nucleus of the thalamus. Furthermore, the repeated immobilization protocols intensified the differences between the effects of 36S and non-point stimulation in the dorsal raphe nucleus (P < 0.05). These data suggest that high levels of stress can interact with and mask the evaluation of specific effects of acupuncture in unanesthetized animals.Universidade Federal Rural do Rio de Janeiro Departamento de Ciências FisiológicasUniversidade de São Paulo Instituto de Ciências Biomédicas Departamento de Fisiologia e BiofísicaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PsicobiologiaUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de FisiologiaUNIFESP, EPM, Depto. de PsicobiologiaUNIFESP, EPM, Depto. de FisiologiaSciEL

Probing Yukawian Gravitational Potential by Numerical Simulations. II. Elliptical Galaxies

Since the Newtonian gravitation is largely used to model with success the structures of the universe, such as galaxies and clusters of galaxies, for example, a way to probe and constrain alternative theories, in the weak field limit, is to apply them to model the structures of the universe. We then modified the well known Gadget-2 code to probe alternative theories of gravitation through galactic dynamics. In particular, we modified the Gadget-2 code to probe alternatives theories whose weak field limits have a Yukawa-like gravitational potential. As a first application of this modified Gadget-2 code we simulate the evolution of elliptical galaxies. These simulations show that galactic dynamics can be used to constrain the parameters associated with alternative theories of gravitation.Comment: 6 pages, 5 figures - To appear in General Relativity and Gravitatio

A solution for galactic disks with Yukawian gravitational potential

We present a new solution for the rotation curves of galactic disks with gravitational potential of the Yukawa type. We follow the technique employed by Toomre in 1963 in the study of galactic disks in the Newtonian theory. This new solution allows an easy comparison between the Newtonian solution and the Yukawian one. Therefore, constraints on the parameters of theories of gravitation can be imposed, which in the weak field limit reduce to Yukawian potentials. We then apply our formulae to the study of rotation curves for a zero-thickness exponential disk and compare it with the Newtonian case studied by Freeman in 1970. As an application of the mathematical tool developed here, we show that in any theory of gravity with a massive graviton (this means a gravitational potential of the Yukawa type), a strong limit can be imposed on the mass (m_g) of this particle. For example, in order to obtain a galactic disk with a scale length of b ~ 10 kpc, we should have a massive graviton of m_g << 10^{-59} g. This result is much more restrictive than those inferred from solar system observations.Comment: 7 pages; 1 eps figure; to appear in General Relativity and Gravitatio

Raman Spectroscopy Studies on the Barocaloric Hybrid Perovskite [(CH₃)₄N][Cd(N₃)₃]

[Abstract] Temperature-dependent Raman scattering and differential scanning calorimetry were applied to the study of the hybrid organic-inorganic azide-perovskite [(CH₃)₄N][Cd(N₃)₃], a compound with multiple structural phase transitions as a function of temperature. A significant entropy variation was observed associated to such phase transitions, |∆S| ~ 62.09 J·kg⁻¹ K⁻¹, together with both a positive high barocaloric (BC) coefficient |δTt/δP| ~ 12.39 K kbar⁻¹ and an inverse barocaloric (BC) coefficient |δTt/δP| ~ −6.52 kbar⁻¹, features that render this compound interesting for barocaloric applications. As for the obtained Raman spectra, they revealed that molecular vibrations associated to the NC₄, N₃⁻ and CH₃ molecular groups exhibit clear anomalies during the phase transitions, which include splits and discontinuity in the phonon wavenumber and lifetime. Furthermore, variation of the TMA⁺ and N₃⁻ modes with temperature revealed that while some modes follow the conventional red shift upon heating, others exhibit an unconventional blue shift, a result which was related to the weakening of the intermolecular interactions between the TMA (tetramethylammonium) cations and the azide ligands and the concomitant strengthening of the intramolecular bondings. Therefore, these studies show that Raman spectroscopy is a powerful tool to gain information about phase transitions, structures and intermolecular interactions between the A-cation and the framework, even in complex hybrid organic-inorganic perovskites with highly disordered phases.Conselho Nacional de Desenvolvimento Científico e Tecnológico (Brasil); 431943/2016-8Fundação de Amparo à Pesquisa e ao Desenvolvimento Científico e Tecnológico do Maranhão (Brasil); COOPI-07771/17Ministerio de Economía y Competitividad; MAT2017-86453-RXunta de Galicia; ED431G/0

Bispectral Index In Calves Anesthetized With Xylazine, Midazolam, Ketamine, Isoflurane And Subjected To Continuous Rate Infusion Of Lidocaine

PURPOSE: To assess the bispectral index (BIS) and recovery in calves anesthetized with xylazine, midazolam, ketamine and isoflurane and subjected to CRI of lidocaine. METHODS: Xilazine was administered followed by ketamine and midazolam, orotracheal intubation and maintenance on isoflurane using mechanical ventilation. Lidocaine (2 mg kg-1 bolus) or saline (0.9%) was administered IV followed by a CRI (100 μg kg-1 minute-1) of lidocaine (L) or saline (C). Were recorded BIS, heart rate (HR), mean arterial pressure (MAP) and rectal temperature (RT) before administration of premedication (TB) and 15 minutes after (TX), before administering lidocaine (T0) and 20, 40, 60 and 80 minutes after the start of the CRI. Time do sternal recumbency (SRE) and standing (ST) and plasma lidocaine concentration also evaluated. RESULTS: In both treatments BIS decreased significantly at all times compared to TB. TX was higher than the subsequent times. HR decreased from baseline at all times and decreased from T40 in L compared to C. SRE was higher in L compared to C. CONCLUSIONS: Bispectral index values were consistent with the degree of hypnosis of the animals. Lidocaine did not potentiate isoflurane anesthesia assessed by BIS in unstimulated calves anesthetized with constant E´Iso. Lidocaine increased the time to sternal recumbency.3016772Haga, H.A., Dolvik, N.I., Evaluation of the bispectral index as an indicator of degree of central nervous system depression in isoflurane-anesthetizes horses (2002) Am J Vet Res, 63 (3), pp. 438-442Henao-Guerreno, P.N., McMurphy, R., Kukanich, B., Hodgson, D.S., Effect of morphine on the bispectral index during isoflurane anesthesia in dogs (2009) Vet Anaesth Analg, 36 (2), pp. 133-143Rosow, C., Manberg, P.J., Bispectral index monitoring (2001) Anesthesiol Clin North Am, 19 (4), pp. 947-966Antognini, J.F., Wang, X.W., Cartens, E., Isoflurane anaesthetic depth in goats monitored using the bispectral index of the electroencephalogram (2000) Vet Res Commun, 24 (6), pp. 361-370Martin-Cancho, M., Lima, J.R., Luis, L., Crisóstomo, V., Ezquerra, L.J., Carrasco, M.S., Usón-Gargallo, J., Bispectral index, spectral edge frequency 95%, and median frequency recorded for various concentration of isoflurane and sevoflurane in pigs (2003) Am J Vet Res, 64 (7), pp. 866-873March, P.A., Muir, W.W., Use of the bispectral index as a monitor of anesthetic depth in cats anesthetized with isoflurane (2003) Am J Vet Res, 64 (12), pp. 1534-1541Campagnol, D., Teixeira Neto, F.J., Monteiro, E.R., Beier, L.S., Aguiar, J.A., Use of bispectral index to monitor depth of anesthesia in isoflurane-anesthetized dogs (2007) Am J Vet Res, 68 (12), pp. 1300-1307Garcia-Pereira, F.L., Greene, A.S., Keegan, R.D., McEwen, M.M., Tibary, A., Effects of intravenous butorphanol on cardiopulmonary function in isoflurane-anesthetized alpacas (2007) Vet Anesth Analg, 34 (4), pp. 269-274Muir, W.W., Wiese, A.J., March, P.A., Effects of morphine, lidocaine, ketamine, and morphine-lidocaine-ketamine drug combination on minimum alveolar concentration in dogs anesthetized with isoflurane (2003) Am J Vet Res, 64 (9), pp. 1155-1160Vesal, N., Spadavecchia, C., Steiner, A., Kirscher, F., Levionnois, O.L., Evaluation of the isoflurane-sparing effects of lidocaine infusion during umbilical surgery in calves (2011) Vet Anaest Analg, 38 (5), pp. 451-460Dzikiti, T.B., Hellebrekers, P., Van Dijk, P., Effects of intravenous lidocaine on isoflurane concentration, physiological parameters, metabolic parameters and stress-related hormones in horses undergoing surgery (2003) J Vet Med A, 50 (4), pp. 190-195Pypendop, B.H., Ilkiw, J.E., The effects of intravenous lidocaine administration on the minimum alveolar concentration of isoflurane in cats. Anesth Analg (2005) Jan, 100 (1), pp. 97-101Doherty, T., Redua, M.A., Queiroz-Castro, P., Egger, C., Cox, S.K., Rohrbach, B.W., Effect of intravenous lidocaine and ketamine on the minimum alveolar concentration of isoflurane in goats (2007) Vet Anaest Analg, 34 (2), pp. 125-131Doherty, T.J., Frazier, D.L., Effect of intravenous lidocaine on halothane minimum alveolar concentration in ponies (1998) Equine Vet J, 30 (4), pp. 300-303Valverde, A., Doherty, T.J., Hérnandez, J., Davies, W., Effect of lidocaine on the minimum alveolar concentration of isoflurane in dogs (2004) Vet Anaest Analg, 31 (4), pp. 264-274. , OctMurrel, J.C., White, K.L., Johnson, C.B., Taylor, P.M., Doherty, T.J., Waterman-Pearson, A.E., Investigation of the EEG effects of intravenous lidocaine during halothane anaesthesia in ponies (2005) Vet Anaest Analg, 32 (4), pp. 212-221Robertson, S.A., Sanches, L.C., Merrit, A.M., Doherty, T.J., Effect of systemic lidocaine on visceral and somatic nociception in conscious horses (2005) Equine Vet J, 37 (2), pp. 122-127Moraes, A.N., Dyson, D.H., Mr, O., McDonell, W.N., Holmberg, D.L., Plasma concentration and cardiovascular influence of lidocaine infusions during isoflurane anesthesia in healthy dogs and dogs with subaortic stenosis (1998) Vet Surg, 27 (5), pp. 486-497Pypendop, B.H., Ilkiw, J.E., Assessment of the hemodynamic effects of lidocaine administered IV in isoflurane-anesthetized cats (2005) Am J Vet Res, 66 (4), pp. 661-668Ringer, S.K., Kalchofner, K., Boller, J., Fürst, A., Bettschart- Wolfensberger, R.A., clinical comparison of two anaesthetic protocols using lidocaine or medetomidine in horses. Vet. Anaesth (2007) Analg, 34 (4), pp. 257-268Valverde, A., Rickey, E., Sinclair, M., Rioja, E., Pedernera, J., Hathway, A., Cruz, A., Comparison of cardiovascular function and quality of recovery in isoflurane-anaesthetised horses administered a constant rate infusion of lidocaine or lidocaine and medetomidine during elective surgery (2010) Equine Vet. J, 42 (3), pp. 192-199Cantalapietra, A.G., Villanueva, B., Pereira, J.L., Anaesthetic potency of isoflurane in cattle: Determination of the minimum alveolar concentration (2000) Vet Anaesth Analg, 27 (1), pp. 22-26Mendes, F.D., Chen, L.S., Borges, A., Babadópulos, T., Ilha, J.O., Alkharfy, K.M., Mendes, G.D., De Nucci G. Ciprofibrate quantification in human plasma by high performance liquid chromatography coupled with electrospray tandem mass spectrometry for pharmacokinetic studies (2012) J Chromatogr B Analyt Technol Biomed Life Sci, 879 (24), pp. 2361-2368. , Aug;15Johansen, J.W., Sebel, P.S., Development and clinical application of electroencephalographic bispectrum monitoring (2000) Anesthesiology, 93 (5), pp. 1336-1344Kissin, I., Depth of anesthesia and bispectral index monitoring (2000) Anesth Analg, 90 (5), pp. 1114-1117March, P.A., Muir, W.W., Bispectral analysis of the electroencephalogram: A review of its development and use in anesthesia (2005) Vet Anaest Analg, 32 (5), pp. 241-255Hans, G.A., Lauwick, S.M., Kaba, A., Bonhomme, V., Struys, M.M., Hans, P.C., Lamy, M.L., Joris, J.L., Intravenous lidocaine infusion reduces bispectral index-guided requirements of propofol only during surgical stimulation (2010) Br J Anaesth, 105 (4), pp. 471-479Wilson, R.A., Soel, L.K., Beztarosti, K., Lamers, J.M., Verdouw, P.D., Negative inotropy of lidocaine: Possible biochemical mechanisms (1993) Eur Heart J, 14 (2), pp. 284-289Pankucsi, C., Varrô, A., Nánási, P.P., Three distinct components of the negative inotropic action of lidocaine in dog Purkinje fiber (1996) Gen Pharmacol, 27 (1), pp. 69-71Valverde, A., Gunkelt, C., Doherty, T.J., Giguère, S., Pollak, A.S., Effect of a constant rate infusion of lidocaine on the quality of recovery from sevoflurane or isoflurane general anaesthesia in horses (2005) Equine Vet J, 37 (6), pp. 559-564Feary, D.J., Mama, K.R., Wagner, E.A., Thomasy, S., Influence of general anesthesia on pharmacokinetics of intravenous lidocaine infusion in horses (2005) Am J Vet Res, 66 (4), pp. 574-580. , Ap

Calcified Abdominal Pregnancy With Eighteen Years Of Evolution: Case Report.

CONTEXT: The lithopedion (calcified abdominal pregnancy) is a rare phenomenon and there are less than 300 cases reported in the medical literature. CASE REPORT: In this case, a 40 year-old patient had had her only pregnancy 18 years earlier, without medical assistance since then. She came to our hospital with pain and tumoral mass of approximately 20 centimeters in diameter. Complementary examinations (abdominal X-ray, ultrasonography and computerized tomography) demonstrated an extra-uterine abdominal 31-week pregnancy with calcification areas. Exploratory laparotomy was performed, with extirpation of a well-conserved fetus with partially calcified ovular membranes.118619219

Light-Front Approach for Pentaquark Strong Decays

Assuming the two diquark structure for the pentaquark state as advocated in the Jaffe-Wilczek model, we study the strong decays of light and heavy parity-even pentaquark states using the light-front quark model in conjunction with the spectator approximation. The narrowness of the Theta width is ascribed to the p-wave configuration of the diquark pair. Taking the Theta width as a benchmark, we estimate the rates of the strong decays Xi_{3/2}-- to Xi- pi-, Sigma- K-, Sigma_{5c}0 to D_s- p, D_{s0}*- p and Xi_{5c}0 to D_s- Sigma+, D_{s0}^{*-} Sigma+ with Sigma_{5c} Xi_{5c} being antisextet charmed pentaquarks and D_{s0}* a scalar strange charmed meson. The ratio of Gamma(P_c to Baryon D_{s0}*)/Gamma(P_c to Baryon D_s) is very useful for verifying the parity of the antisextet charmed pentaquark P_c. It is expected to be of order unity for an even parity P_c and much less than one for an odd parity pentaquark.Comment: 24 pages, 2 figure