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

Literature review and Case report : Treatment of recurrent attacks of idiopathic high-flow priapism in 13-year-old boy with Diazepam and local ice pad. Case report and literature review

Objective: Priapism is a fairly uncommon presentation to the emergency paediatrics department, but when it does present, it represents a real urologic emergency. Prompt treatment will decrease the risk of permanent consequences including impotency. Treatment should be based on aetiology, followed by an organized approach [1]. This report discusses a case of recurrent attacks of idiopathic priapism in a 13-year-old boy comparing the treatment with other experiences. Patient and methods: A 13-year-old boy was diagnosed at our hospital with idiopathic priapism which always happened at waking up time and which responded to oral diazepam and local ice pad therapy. Diagnosis was confirmed after exclusion of all other causes. This type of management was compared with retrospectively reviewed and reported in the PubMed web site. Results: Successful treatment of recurrent idiopathic priapism with oral administration of diazepam and local ice pad. Conclusion: As the problem was solved completely after the fifth attack of priapism, the utilisation of oral diazepam and local ice pad therapy may be considered as a less invasive method for the management of recurrent idiopathic priapism in children

Oxidative stress and antioxidant status in patients with erectile dysfunction

Introduction. Erectile dysfunction (ED) is increasingly recognized as a public health problem. The interaction between nitric oxide and reactive oxygen species is one of the important mechanisms implicated in the pathophysiological process of ED. Plasma contains various antioxidant components to prevent free-radical injury. Aim. The aim of this study was to determine and compare the oxidative and antioxidant status of peripheral venous blood in patients with ED of arteriogenic and non-arteriogenic origin. Methods. Oxidative stress and antioxidant status were assessed in 40 patients with ED and 20 healthy controls. Main Outcome Measures. Plasma reactive oxygen metabolite (ROM) concentrations were measured as an indicator of oxidative stress, and plasma total antioxidant status (TAS) to indicate antioxidant defense. Results. Plasma ROM concentrations were higher (349.75 +/- 53.35 standard deviation [SD] U.Carr vs. 285.43 +/- 25.58 U.Carr, P < 0.001) and plasma TAS lower (0.54 +/- 0.16 SD mmol/L vs. 0.94 +/- 0.28 SD mmol/L, P < 0.0001) in patients with arteriogenic ED in comparison to those in patients with non-arteriogenic ED. Plasma ROM and TAS in controls were not significantly different from those in non-arteriogenic ED. Conclusions. This observation may be useful to better understand and distinguish arteriogenic from non-arteriogenic ED using laboratory tests. In addition, our findings provide important support for an antioxidant therapy to try to correct oxidative stress in arteriogenic ED patients. Barassi A, Colpi GM, Piediferro G, Dogliotti G, Melzi D'Eril GV, and Corsi MM. Oxidative stress and antioxidant status in patients with erectile dysfunction

Asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA) and L-arginine in patients with arteriogenic and non-arteriogenic erectile dysfunction

The plasma concentration of asymmetrical dimethylarginine (ADMA), an inhibitor of nitric oxide synthase, has been linked to endothelial dysfunction. We investigated the relation between ADMA, symmetric dimethylarginine (SDMA) and L-arginine concentrations and erectile dysfunction. We compared plasma levels of ADMA, SDMA and L-arginine in 61 men in good health with erectile dysfunction of arteriogenic and non-arteriogenic origin. Diagnosis of erectile dysfunction was based on the International Index of Erectile Function Score and its aetiology was classified with penile echo-colour-Doppler in basal condition and after intracavernous injection of prostaglandin E1. The ADMA and SDMA concentrations were significantly higher in men with arteriogenic erectile dysfunction compared with those with erectile dysfunction of non-arteriogenic origin (p 0.05) nor between each of the two erectile dysfunction subgroups and controls (p > 0.05). The L-arginine/ADMA and the L-arginine/SDMA ratios in arteriogenic erectile dysfunction subgroups were significantly lower than both in controls (p 0.05). We conclude that ADMA and SDMA concentrations are significantly higher and L-arginine/ADMA ratio lower in patients who have arteriogenic erectile dysfunction compared with both patients with non-arteriogenic erectile dysfunction and controls. The negative correlation between ADMA and severity of erectile dysfunction is present only in patients with arteriogenic erectile dysfunction. This study supports the importance to always distinguish arteriogenic from non-arteriogenic erectile dysfunction patients to study the complicate erectogenic mechanisms that lead to erectile dysfunction and also to provide potential therapeutic agents for patients with arteriogenic erectile dysfunction

Search for intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network

Gravitational-wave astronomy has been firmly established with the detection of gravitational waves from the merger of ten stellar-mass binary black holes and a neutron star binary. This paper reports on the all-sky search for gravitational waves from intermediate mass black hole binaries in the first and second observing runs of the Advanced LIGO and Virgo network. The search uses three independent algorithms: two based on matched filtering of the data with waveform templates of gravitational-wave signals from compact binaries, and a third, model-independent algorithm that employs no signal model for the incoming signal. No intermediate mass black hole binary event is detected in this search. Consequently, we place upper limits on the merger rate density for a family of intermediate mass black hole binaries. In particular, we choose sources with total masses M=m1+m2ϵ[120,800] M and mass ratios q=m2/m1ϵ[0.1,1.0]. For the first time, this calculation is done using numerical relativity waveforms (which include higher modes) as models of the real emitted signal. We place a most stringent upper limit of 0.20 Gpc-3 yr-1 (in comoving units at the 90% confidence level) for equal-mass binaries with individual masses m1,2=100 M and dimensionless spins χ1,2=0.8 aligned with the orbital angular momentum of the binary. This improves by a factor of ∼5 that reported after Advanced LIGO's first observing run. © 2019 American Physical Society

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2 Ma-1.0 Ma. We use the null result to constrain the binary merger rate of (0.2 M, 0.2 M) binaries to be less than 3.7×105 Gpc-3 yr-1 and the binary merger rate of (1.0 M, 1.0 M) binaries to be less than 5.2×103 Gpc-3 yr-1. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2 M black holes to account for less than 16% of the dark matter density and a population of merging 1.0 M black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries. © 2019 American Physical Society

GW190814: gravitational waves from the coalescence of a 23 solar mass black hole with a 2.6 solar mass compact object

We report the observation of a compact binary coalescence involving a 22.2–24.3 Me black hole and a compact object with a mass of 2.50–2.67 Me (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO’s and Virgo’s third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg2 at a distance of - + 241 45 41 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves, - + 0.112 0.009 0.008, and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The dimensionless spin of the primary black hole is tightly constrained to �0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1–23 Gpc−3 yr−1 for the new class of binary coalescence sources that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries