7,480 research outputs found
Radiative Models of Sagittarius A* and M87 from Relativistic MHD Simulations
Ongoing millimeter VLBI observations with the Event Horizon Telescope allow
unprecedented study of the innermost portion of black hole accretion flows.
Interpreting the observations requires relativistic, time-dependent physical
modeling. We discuss the comparison of radiative transfer calculations from
general relativistic MHD simulations of Sagittarius A* and M87 with current and
future mm-VLBI observations. This comparison allows estimates of the viewing
geometry and physical conditions of the Sgr A* accretion flow. The viewing
geometry for M87 is already constrained from observations of its large-scale
jet, but, unlike Sgr A*, there is no consensus for its millimeter emission
geometry or electron population. Despite this uncertainty, as long as the
emission region is compact, robust predictions for the size of its jet
launching region can be made. For both sources, the black hole shadow may be
detected with future observations including ALMA and/or the LMT, which would
constitute the first direct evidence for a black hole event horizon.Comment: 8 pages, 2 figures, submitted to the proceedings of AHAR 2011: The
Central Kiloparse
Asymptotic behaviour of multiple scattering on infinite number of parallel demi-planes
The exact solution for the scattering of electromagnetic waves on an infinite
number of parallel demi-planes has been obtained by J.F. Carlson and A.E. Heins
in 1947 using the Wiener-Hopf method. We analyze their solution in the
semiclassical limit of small wavelength and find the asymptotic behaviour of
the reflection and transmission coefficients. The results are compared with the
ones obtained within the Kirchhoff approximation
Dual production of polyhydroxyalkanoates and antibacterial/antiviral gold nanoparticles
Gold nanoparticles (AuNPs) have been explored for their use in medicine. Here, we report a sustainable, and cost-effective method to produce AuNPs using a bacterial strain such as Pseudomonas mendocina CH50 which is also known to be a polyhydroxyalkanoate (PHA) producer. A cell-free bacterial supernatant, which is typically discarded after PHA extraction, was used to produce spherical AuNPs of 3.5 ± 1.5 nm in size as determined by Transmission Electron Microscopy (TEM) analysis. The AuNPs/PHA composite coating demonstrated antibacterial activity against Staphylococcus aureus 6538P, and antiviral activity, with a 75% reduction in viral infectivity against SARS-CoV-2 pseudotype virus
ANTICARSIA GEMMATALIS (LEPIDOPTERA: NOCTUIDAE) IN PUERTO RICO: A NEW HOST-PLANT AND TWO NEW BIRD PREDATORS
ANTICARSIA GEMMATALIS (LEPIDOPTERA: NOCTUIDAE) IN PUERTO RICO: A NEW HOST-PLANT AND TWO NEW BIRD PREDATOR
Comparison of the telegraph and hyperdiffusion approximations in cosmic-ray transport
The telegraph equation and its generalizations have been repeatedly considered in the models of diffusive cosmic-ray transport. Yet the telegraph model has well-known limitations, and analytical arguments suggest that a hyperdiffusion model should serve as a more accurate alternative to the telegraph model, especially on the timescale of a few scattering times. We present a detailed side-by-side comparison of an evolving particle density profile, predicted by the telegraph and hyperdiffusion models in the context of a simple but physically meaningful initial-value problem, compare the predictions with the solution based on the Fokker–Planck equation, and discuss the applicability of the telegraph and hyperdiffusion approximations to the description of strongly anisotropic particle distributions
Small animal disease surveillance: respiratory disease 2017
This report focuses on surveillance for respiratory disease in companion animals. It begins with an analysis of data from 392 veterinary practices contributing to the Small Animal Veterinary Surveillance Network (SAVSNET) between January and December 2017.
The following section describes canine respiratory coronavirus infections in dogs, presenting results from laboratory-confirmed cases across the country between January 2010 and December 2017. This is followed by an update on the temporal trends of three important syndromes in companion animals, namely gastroenteritis, pruritus and respiratory disease, from 2014 to 2017.
A fourth section presents a brief update on Streptococcus equi subspecies zooepidemicus in companion animals. The final section summarises some recent developments pertinent to companion animal health, namely eyeworm (Thelazzia callipaeda) infestations in dogs imported to the UK and canine influenza virus in the USA and Canada
The combined molecular adjuvant CASAC enhances the CD8+ T cell response to a tumor-associated self-antigen in aged, immunosenescent mice
BACKGROUND: Ineffective induction of T cell mediated immunity in older individuals remains a persistent challenge for vaccine development. Thus, there is a need for more efficient and sophisticated adjuvants that will complement novel vaccine strategies for the elderly. To this end, we have investigated a previously optimized, combined molecular adjuvant, CASAC (Combined Adjuvant for Synergistic Activation of Cellular immunity), incorporating two complementary Toll-like receptor agonists, CpG and polyI:C, a class-II epitope, and interferon (IFN)-γ in aged mice. FINDINGS: In aged mice with typical features of immunosenescence, antigen specific CD8+ T cell responses were stimulated after serial vaccinations with CASAC or Complete/Incomplete Freund's Adjuvant (CFA/IFA) and a class I epitope, deriving either from ovalbumin (SIINFEKL, SIL) or the melanoma-associated self-antigen, tyrosinase-related protein-2 (SVYDFFVWL, SVL). Pentamer analysis revealed that aged, CASAC/SIL-vaccinated animals had substantially higher frequencies of H-2K(b)/SIL-specific CD8+ T cells compared to the CFA/IFA-vaccinated groups. Similarly, higher frequencies of H-2K(b)/SVL-pentamer+ and IFN-γ+ CD8+ T cells were detected in the aged, CASAC + SVL-vaccinated mice than in their CFA/IFA-vaccinated counterparts. In both antigen settings, CASAC promoted significantly better functional CD8+ T cell activity. CONCLUSION: These studies demonstrate that functional CD8+ T cells, specific for both foreign and tumour-associated self-antigens, can be effectively induced in aged immunosenescent mice using the novel multi-factorial adjuvant CASAC
Silent onset of postmenopausal endometriosis in a woman with renal failure in hormone replacement therapy: a case report
<p>Abstract</p> <p>Introduction</p> <p>Postmenopausal endometriosis is a rare form of a common disease, since the absence of estrogenic hormone production should halt disease progression.</p> <p>Case presentation</p> <p>We present the case of a 54-year-old Italian Caucasian woman in surgical menopause with a history of ovarian endometriosis, who underwent voluntary hormone replacement therapy for seven years. She developed postrenal renal failure due to bilateral compression of the pelvic ureteral tract caused by two large, deeply infiltrating endometriotic nodules with no pelvic pain. She underwent operative laparoscopy with adhesiolysis of enteroenteric adhesions and excision of the endometriotic nodules encompassing the juxtavesical tract of the ureters, without obtaining improvement of renal failure.</p> <p>Conclusion</p> <p>Postmenopausal endometriosis can manifest itself in an unpredictable and potentially very serious manner. It is therefore important to carefully evaluate the risks and benefits of administering hormone replacement therapy to patients with previous endometriosis.</p
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