290 research outputs found
Numerical Solutions of ideal two-fluid equations very closed to the event horizon of Schwarzschild black hole
The 3+1 formalism of Thorne, Price and Macdonald has been used to derive the
linear two-fluid equations describing transverse and longitudinal waves
propagating in the two-fluid ideal collisionless plasmas surrounding a
Schwarzschild black hole. The plasma is assumed to be falling in radial
direction toward the event horizon. The relativistic two-fluid equations have
been reformulate, in analogy with the special relativistic formulation as
explained in an earlier paper, to take account of relativistic effects due to
the event horizon. Here a WKB approximation is used to derive the local
dispersion relation for these waves and solved numerically for the wave number
k.Comment: 16 pages, 15 figures. arXiv admin note: text overlap with
arXiv:0902.3766, arXiv:0807.459
Importance of Selecting a Suitable Analysis Frequency Range in Impact Force Identification for Automobile Test Rig
In this study, the effectiveness of selecting a suitable analysis frequency range in impact force identification is highlighted. A methodology that utilizesOperating Deflection Shape (ODS) analysis, Modal Analysis (MA) and Modal Transformation Method (MTM) to evaluate the dynamic force in three cases of analysis frequency ranges was presented. These three cases are the overestimated, even-estimated, and under-estimated cases, which consist of higher, similar andlower analysis frequency range respectively, compared to the actual excitation frequency range. The performance of this approach was demonstrated via experiment. A Perspex plate with four ground supports was used as the automobile test rig. By measuring the acceleration response and Frequency Response Function (FRF) of the test rig, the time history of unknown force was recovered by the proposed method where the impact location was known in advance. It showed that the force identification result for even-estimated case falls within acceptable range while the force identification result for over-estimated and under-estimated cases isnot acceptable
Influence of Falling Height on the Behavior of Skid- Launching Free-Fall Lifeboat in Regular Waves
This paper numerically investigated the influence of falling height on the behavior of the skid-launching free-fall
lifeboat (FFLB) in regular waves. The boat has been treated as a rigid body when the differential equations of motion
for the four falling phases, i.e., sliding or ramp phase, rotation phase, free-fall phase and water entry phase of the
lifeboat were solved in the time domain. The hydrodynamic characteristics of the lifeboat has been studied for
different falling heights such as H = 1.5m, 1.75m and 2.00m. Horizontal and vertical excursions and the rotation of
the axis of the boat have been computed at different time along with its horizontal and vertical velocities.
Hydrodynamic forces and accelerations at normal and axial directions have also been determined. At first the analysis
has been done in still water and then in regular wave with amplitude of 0.5m and a period of 2.0 sec. In all of the
cases, effects of regular wave are shown by comparing the results with those considering the falling of FFLB into
calm water
Efecto hepatoprotector del insaponificable de los aceites de oliva, linaza y sésamo contra la lesión hepática inducida por tetracloruro de carbono en ratas
In the present study, the hepatoprotective activity of the unsaponifiable matter (UNSAP) of olive oil, linseed, and sesame oils against CCl4-induced liver toxicity in rats was investigated. In a preliminary antioxidant study, UNSAP showed pronounced DPPH radical scavenging activity (IC50 6.2-10.8 mg/mL). The constituents of UNSAP were determined by GC-MS. The subcutaneous administration of CCl4, caused liver injury. The hepatoprotective effect of UNSAP was comparable to that of α-tocopherol, a standard antioxidant agent. The co-administration of the investigated UNSAP normalized the activities of serum marker enzymes, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Furthermore, the serum alkaline phosphatase (ALP) activity and hepatic malondialdehyde (MDA) level were found to be alleviated by pre-treatment with the UNSAP. A histopathological evaluation showed marked improvement in the liver of UNSAP- and α-Tocopherol-treated animals. The hepatoprotective effect could be attributed to the antioxidant characteristics of UNSAP.En el presente estudio, se investigĂł la actividad hepatoprotectora de la materia insaponificable (UNSAP) de los aceites de oliva, linaza y sĂ©samo contra la toxicidad hepática inducida por CCl4 en ratas. En un estudio preliminar de antioxidantes, UNSAP mostrĂł una pronunciada actividad de captaciĂłn de radicales DPPH (IC50 6.2-10.8 mg / mL). Los constituyentes del UNSAP fueron determinados por GC-MS. La administraciĂłn de CCl4, por vĂa subcutánea, causĂł lesiĂłn hepática. El efecto hepatoprotector del UNSAP fue comparable al del α-Tocoferol, un agente antioxidante estándar. La administraciĂłn conjunta del UNSAP normalizĂł las actividades de las enzimas marcadoras sĂ©ricas, alanina aminotransferasa (ALT) y aspartato aminotransferasa (AST). Además, se encontrĂł que la actividad de la fosfatasa alcalina en suero (ALP) y el nivel de malondialdehĂdo hepático (MDA) se mitigan con el tratamiento previo con UNSAP. La evaluaciĂłn histopatolĂłgica mostrĂł una mejorĂa notable en el hĂgado de los animales tratados con UNSAP y α-Tocopherol. El efecto hepatoprotector podrĂa atribuirse a las caracterĂsticas antioxidantes de UNSAP
Actividades antioxidantes, antiinflamatorias y citotĂłxicas de la fracciĂłn insaponificable de aceite de oliva virgen extra
The health benefits of olive oil are well-known. In this study, the unsaponifiable fraction of extra virgin olive oil (Unsap) was investigated for reducing power capacity, ferric reducing antioxidant power, fer-rous chelating activity and nitric oxide inhibition. The present study was also designed to evaluate the in vitro cytotoxic effect of the Unsap against human carcinoma cells. The anti-inflammatory potential of Unsap has been determined via the inhibition of Human Cyclooxygenases. The results showed that Unsap is efficient for ferric reducing antioxidant power and nitric oxide inhibition. Unsap has a selective effect as anti-inflammatory agent. The results showed moderate to good in vitro antitumor activities of Unsap against human liver, lung and pancreas cancer cells with IC50 ranging from 19.6 to 30.4 ÎĽg/mL and good selectivity index (≥ 2). In conclusion, Unsap represents a promising and safe antitumor and antioxidant material that supports the need for further investigation.Los beneficios para la salud del aceite de oliva son bien conocidos. En este estudio, se investigĂł la fracciĂłn insaponificable del aceite de oliva virgen extra (Insap) para reducir el poder antioxidante fĂ©rrico, la actividad quelante ferrosa y la inhibiciĂłn del Ăłxido nĂtrico. El presente estudio tambiĂ©n fue diseñado para evaluar el efecto citotĂłxico in vitro del Insap contra las cĂ©lulas de carcinoma humano. La potencialidad antiinflamatoria del Insap se ha determinado mediante la inhibiciĂłn de las ciclooxigenasas humanas. Los resultados mostraron que el Insap es eficiente para reducir el poder antioxidante fĂ©rrico y la inhibiciĂłn del Ăłxido nĂtrico. El Insap tiene un efecto selectivo como agente antiinflamatorio. Los resultados mostraron actividades antitumorales in vitro del Insap de moderadas a buenas contra cĂ©lulas de cáncer de hĂgado, pulmĂłn y páncreas humano con una CI50 que varĂa de 19,6 a 30,4 ÎĽg/ml y por su buen Ăndice de selectividad ( ≥ 2). En conclusiĂłn, el Insap contiene material antitumoral y antioxidante prometedor y seguro que será respaldado por investiga-ciones adicionales
Transverse Wave Propagation in Relativistic Two-fluid Plasmas in de Sitter Space
We investigate transverse electromagnetic waves propagating in a plasma in
the de Sitter space. Using the 3+1 formalism we derive the relativistic
two-fluid equations to take account of the effects due to the horizon and
describe the set of simultaneous linear equations for the perturbations. We use
a local approximation to investigate the one-dimensional radial propagation of
Alfv\'en and high frequency electromagnetic waves and solve the dispersion
relation for these waves numerically.Comment: 19 pages, 12 figure
Bilateral Torsion of Intra-abdominal Seminoma Presenting with Acute Abdomen and Intra-peritoneal Bleeding: A Case Report
Seminoma is the most frequently reported tumor in patients with intra-abdominal testicles. In very rare cases, it might present with torsion or rupture. We report a 41-year-old man who presented with acute abdominal pain due to torsion of large bilateral intra-abdominal testicular tumors with rupture of the right-sided mass. Bilateral orchiectomy was performed and histopathological examination revealed bilateral seminoma. Postoperative staging imaging displayed no lymphadenopathy or metastatic lesions. No adjuvant treatment was required and the patient is clinically well and under regular follow-up. This case represents an extremely rare presentation of bilateral testicular cancer with a pleasant outcome
High rate of multidrug-resistant Enterobacteriaceae carrying ESBL and plasmid-borne AmpC Ăź-lactamase in a Malaysian community
Daniel Reidpath - ORCID: 0000-0002-8796-0420
https://orcid.org/0000-0002-8796-0420Background: Even though Southeast Asia is generally regarded as the hotspot for antibiotic resistance, there have been limited studies investigating the prevalence of antibiotic resistance among healthy people in the region. We aimed to investigate the prevalence of two Ăź-lactamase genes, ESBL and plasmid-borne AmpC (pAmpC) among Enterobacteriaceae in a healthy community in Malaysia.
Methods and materials: We collected stool samples and screened for ESBL and pAmpC-producing Enterobacteriaceae using phenotypic and genotypic methods. The susceptibility profile of the isolates towards 13 different antibiotics was observed. Plasmid replicon group, E. coli phylogenetic group and MLST analyses were also conducted to observe the spread pattern of these resistance genes. Risk factors associated with the carriage of ESBL or pAmpC-producing Enterobacteriaceae were then analysed.
Results: ESBL and pAmpC production was observed in 21.6% (95% CI 13.9–28.8%) and 32.1% (95% CI 24.5–38.9%) of the participants, respectively. A high proportion of the isolates (99.9%, 95% CI 98.6–99.9%) were multidrug-resistant regardless of the resistance genes carried. Although E. coli B2:ST131 was detected, there was no dominance of a specific clonal strain. Possession of multiple plasmid groups was common, with incFIB being the most frequently detected type. Mixed effect logistic regression analysis found that ESBL production was associated with having allergy (p = 0.01, OR 3.86, 95% CI 1.32–11.23) and consumption of chicken meat (p = 0.02, OR = 8.66, 95% CI = 1.40–53.29), while consumption of fermented food significantly lowers the risk of colonisation with pAmpC producing Enterobacteriaceae (p = 0.02, OR 0.23, 95% CI = 0.06–0.79).
Conclusion: The high prevalence of Ăź-lactamase and multidrug resistance suggests that antibiotic resistance is endemic among healthy people in Malaysia.https://doi.org/10.1016/j.ijid.2020.09.078101pubpubSuppl.
Collapsing shear-free perfect fluid spheres with heat flow
A global view is given upon the study of collapsing shear-free perfect fluid
spheres with heat flow. We apply a compact formalism, which simplifies the
isotropy condition and the condition for conformal flatness. This formalism
also presents the simplest possible version of the main junction condition,
demonstrated explicitly for conformally flat and geodesic solutions. It gives
the right functions to disentangle this condition into well known differential
equations like those of Abel, Riccati, Bernoulli and the linear one. It yields
an alternative derivation of the general solution with functionally dependent
metric components. We bring together the results for static and time- dependent
models to describe six generating functions of the general solution to the
isotropy equation. Their common features and relations between them are
elucidated. A general formula for separable solutions is given, incorporating
collapse to a black hole or to a naked singularity.Comment: 26 page
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
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