1,100 research outputs found
Opacities and spectra of hydrogen atmospheres of moderately magnetized neutron stars
There is observational evidence that central compact objects (CCOs) in supernova remnants have moderately strong magnetic fields G. Meanwhile, available models of partially ionized hydrogen atmospheres of neutron stars with strong magnetic fields are restricted to G. We extend the equation of state and radiative opacities, presented in previous papers for 10^{12}\mbox{ G}\lesssim B \lesssim 10^{15} G, to weaker fields. An equation of state and radiative opacities for a partially ionized hydrogen plasma are obtained at magnetic fields , temperatures , and densities typical for atmospheres of CCOs and other isolated neutron stars with moderately strong magnetic fields. The first- and second-order thermodynamic functions, monochromatic radiative opacities, and Rosseland mean opacities are calculated and tabulated, taking account of partial ionization, for 3\times10^{10}\mbox{ G}\lesssim B\lesssim 10^{12} G, K K, and a wide range of densities. Atmosphere models and spectra are calculated to verify the applicability of the results and to determine the range of magnetic fields and effective temperatures where the incomplete ionization of the hydrogen plasma is important.The work of AYP on calculation of the opacities and polarizabilities (Sect. 4) has been supported by the Russian Science Foundation (grant 14-12-00316). WCGH appreciates use of computer facilities at KIPAC
Fatal abomasal sand impaction in a giraffe calf (Giraffa camelopardalis) at the University of Ilorin zoological garden
A post-mortem examination was carried out on a 4-month-old giraffe which was reported dead early hours of the morning in the zoological garden, University of Ilorin. The carcass of the animal appeared slightly emaciated and on opening of the carcass the abomasum was distended with a hard mass felt inside the organ. On opening of the organ, it was filled with sand and weighing 3.8kg. Geophagia due to variousĀ factors were queried in the cause of the condition including seasonal prevalence, nutrient deficiencies,Ā feeding regimen and also housing inadequacies. Although poor milk intake, absence of maternal nurturingĀ and inadequate captive conditions are the most likely causes of geophagia which eventually led to theĀ death of the animal.Keywords: Abomasum, Sand impaction, Geophagia, Giraffe, Nigeri
Efficacy of a Novel Injection Lipolysis to Induce Targeted Adipocyte Apoptosis: A Randomized, Phase IIa Study of CBL-514 Injection on Abdominal Subcutaneous Fat Reduction
Background: CBL-514 is a novel injectable drug that may be safe and efficacious for localized abdominal subcutaneous fat reduction. Objectives: The aim of this study was to assess the safety and efficacy of CBL-514 in reducing abdominal subcutaneous fat volume and thickness. Methods: This Phase IIa, open-label, random allocation study consisted of a 6-week treatment period and follow-up at 4 and 8 weeks following the last treatment. Participants were randomly allocated to receive 1.2 mg/cm2 (180 mg), 1.6 mg/cm2 (240 mg), or 2.0 mg/cm2 (300 mg) of CBL-514 with up to 4 treatments, each comprising 60 injections into the abdominal adipose layer. Changes in abdominal subcutaneous fat were assessed by ultrasound at follow-up visits. Treatment-emergent adverse events were recorded. Results: Higher doses of CBL-514 (unit dose, 2.0 and 1.6 mg/cm2) significantly improved the absolute and percentage reduction in abdominal fat volume (P < 0.00001) and thickness (P < 0.0001) compared with baseline. Although the COVID-19 pandemic halted some participant recruitment and follow-ups, analysis was unaffected, even after sample size limitations. Conclusions: CBL-514 injection at multiple doses up to 300 mg with a unit dose of 2.0 mg/cm2 is safe, well-tolerated, and reduced abdominal fat volume and thickness by inducing adipocyte apoptosis. Although other procedures exist to treat abdominal fat, they have limitations and may cause complications. At a dose of 2.0 mg/cm2, CBL-514 safely and significantly reduced abdominal fat volume by 24.96%, making it a promising new treatment for routine, nonsurgical abdominal fat reduction in dermatologic clinics. Level of Evidence: 4
Medical and dental studentsā willingness to administer treatments and procedures for patients living with AIDS
Background. Nearly three decades after the discovery of the human immunodeficiency virus (HIV), acquired immunodeficiency syndrome (AIDS)epidemics continue to pose significant challenges to low-income countries in sub-Saharan Africa.Objective. To assess medical and dental studentsā willingness to perform specific techniques and procedures on people living with AIDS (PLWA).Methods. A survey was done among medical and dental students (N=304) at a Nigerian University using a 21-item questionnaire that elicitedresponses on sociodemographic characteristics and willingness to perform specific techniques and procedures. Analysis of variance (ANOVA) andan independent t-test were used to determine the influence of sociodemographic variables. Multiple regression analyses were used to determine the predictors of willingness.Results. The cohort of medical and dental students was willing to care for PLWA. Almost all medical students were either undecided or unwillingto perform mouth-to-mouth resuscitation. A higher proportion of dental students were either undecided or unwilling to assist during surgery, toothextractions and other procedures they considered to be invasive. More medical than dental students were willing to carry out surgical procedures.Previous personal encounters with AIDS patients, religion, and satisfaction with instructions influenced medical and dental studentsā willingness tocare for PLWA, while knowing a family member living with AIDS (R2=0.22, p<0.001) was the strongest predictor of willingness to care for PLWA.Conclusion. Extensive use of clinical clerkships and exposure through direct experience are viable strategies necessary for optimising and enhancingmedical and dental studentsā dispositions to perform procedures and care for PLWA
Cyclic deformation characteristics of S355 and S690 steels under different loading protocols
Despite of excellent high strength to self-weight ratios of the S690 steels, when compared with the S355 steels, there is a widespread concern regarding the ductility of the S690 steels. It is generally considered that the ductility of the S690 steels is significantly lower than that of the S355 steels ā this is the general understandings the authors attempt to investigate. This paper presents an experimental investigation into cyclic deformation characteristics of both S355 and S690 steels through low-cycle high-strain cyclic tests with two different loading protocols. A detailed account of the results of 32 cyclic tests on both the S355 and the S690 funnel-shaped coupons is presented. Effects of four different target strains and two different loading frequencies are also examined in details. For the ranges of loading protocols, strain amplitudes, and frequencies considered, the hysteretic responses of these coupons of the two steels are compared directly in terms of engineering stressāstrain curves based on their nominal diameters. Microstructures of the fractured coupons of the two steels are also identified for comparison. Contrary to the general understandings, it is demonstrated that the high strength S690 steels do have a good ductility under both monotonic and cyclic actions. Moreover, depending on specific loading protocols and target strains, the cyclic deformation characteristics of the S690 steels are demonstrated to be superior to those of the S355 steels in terms of the number of cycles completed prior to failure and their corresponding energy dissipation characteristic under various target strains up to Ā±10.0%. The findings of this experimental investigation highlight the importance of establishing ductility requirements and cyclic deformation characteristics for the high strength S690 steels in accordance with specifically designed cyclic tests rather than relying solely on conventional monotonic tensile tests
Current progress on removal of recalcitrance coloured particles from anaerobically treated effluent using coagulationāflocculation
The palm oil industry is the most important agro industries in Malaysia and most of the mills adopt anaerobic digestion as their primary treatment for palm oil mill effluent (POME). Due to the public concern, decolourisation of anaerobically treated POME (AnPOME) is becoming a great concern. Presence of recalcitrant-coloured particles hinders biological processes and coagulationāflocculation may able to remove these coloured particles. Several types of inorganic and polymers-based coagulant/flocculant aids for coagulationāflocculation of AnPOME have been reviewed. Researchers are currently interested in using natural coagulant and flocculant aids. Modification of the properties of natural coagulant and flocculant aids enhanced coagulationāflocculation performance. Modelling and optimization of the coagulationāflocculation process have also been reviewed. Chemical sludge has the potential for plant growth that can be evaluated through pot trials and phytotoxicity test
Soft excess in the quiescent Be/X-ray pulsar RX J0812.4-3114
We report a 72 ks XMM-Newton observation of the Be/X-ray pulsar (BeXRP) RX J0812.4-3114 in quiescence (L-X approximate to 1.6 x 10(33) erg s(-1)). Intriguingly, we find a two-component spectrum, with a hard power-law (Gamma approximate to 1.5) and a soft blackbody-like excess below keV. The blackbody component is consistent in kT with a prior quiescent Chandra observation reported by Tsygankov et al. and has an inferred blackbody radius of;----10 km, consistent with emission from the entire neutron star (NS) surface. There is also mild evidence for an absorption line at approximate to and/or approximate to 1.4 keV. The hard component shows pulsations at P approximate to 31.908 s (pulsed fraction 0.84 +/- 0.10), agreeing with the pulse period seen previously in outbursts, but 110 pulsations were found in the soft excess (pulsed fraction less than or similar to 31 per cent). We conclude that the pulsed hard component suggests low-level accretion on to the NS poles, while the soft excess seems to originate from the entire NS surface. Wc speculate that, in quiescence, the source switches between a soft, thermal-dominated state (when the propeller effect is at work) and a relatively hard state with low-level accretion, and use the propeller cut-off to estimate the ma.gnetic field of the system to be less than or similar to 8.4 x 10(11)G. We compare the quiescent thermal L-X predicted by the standard deep crustal heating model to our observations and find that RX J0812.4-31.14 has a high thermal L-X, at or above the prediction for minimum cooling mechanisms. This suggests that RX J0812.4-3114 either contains a relatively low-mass NS with minimum cooling, or that the system may be young enough that the NS has not fully cooled from the supernova explosion
Cooling of Dark-Matter Admixed Neutron Stars with density-dependent Equation of State
We propose a dark-matter (DM) admixed density-dependent equation of state
where the fermionic DM interacts with the nucleons via Higgs portal. Presence
of DM can hardly influence the particle distribution inside neutron star (NS)
but can significantly affect the structure as well as equation of state (EOS)
of NS. Introduction of DM inside NS softens the equation of state. We explored
the effect of variation of DM mass and DM Fermi momentum on the NS EOS.
Moreover, DM-Higgs coupling is constrained using dark matter direct detection
experiments. Then, we studied cooling of normal NSs using APR and DD2 EOSs and
DM admixed NSs using dark-matter modified DD2 with varying DM mass and Fermi
momentum. We have done our analysis by considering different NS masses. Also DM
mass and DM Fermi momentum are varied for fixed NS mass and DM-Higgs coupling.
We calculated the variations of luminosity and temperature of NS with time for
all EOSs considered in our work and then compared our calculations with the
observed astronomical cooling data of pulsars namely Cas A, RX J0822-43, 1E
1207-52, RX J0002+62, XMMU J17328, PSR B1706-44, Vela, PSR B2334+61, PSR
B0656+14, Geminga, PSR B1055-52 and RX J0720.4-3125. It is found that APR EOS
agrees well with the pulsar data for lighter and medium mass NSs but cooling is
very fast for heavier NS. For DM admixed DD2 EOS, it is found that for all
considered NS masses, all chosen DM masses and Fermi momenta agree well with
the observational data of PSR B0656+14, Geminga, Vela, PSR B1706-44 and PSR
B2334+61. Cooling becomes faster as compared to normal NSs in case of
increasing DM mass and Fermi momenta. It is infered from the calculations that
if low mass super cold NSs are observed in future that may support the fact
that heavier WIMP can be present inside neutron stars.Comment: 24 Pages, 15 Figures and 2 Tables. Version accepted in The European
Physical Journal
Gauge-Higgs Unification In Spontaneously Created Fuzzy Extra Dimensions
We propose gauge-Higgs unification in fuzzy extra dimensions as a possible
solution to the Higgs naturalness problem. In our approach, the fuzzy extra
dimensions are created spontaneously as a vacuum solution of certain
four-dimensional gauge theory. As an example, we construct a model which has a
fuzzy torus as its vacuum. The Higgs field in our model is associated with the
Wilson loop wrapped on the fuzzy torus. We show that the quadratic divergence
in the mass of the Higgs field in the one-loop effective potential is absent.
We then argue based on symmetries that the quantum corrections to the Higgs
mass is suppressed including all loop contributions. We also consider a
realization on the worldvolume theory of D3-branes probing orbifold with discrete torsion.Comment: 1+38 pages, 4 figures v2: refs adde
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