Averaging the spectral shapes

The methods of obtaining the average spectral shape in a low statistics regime are presented. Different approaches to averaging are extensively tested with simulated spectra, based on the ASCA responses. The issue of binning up the spectrum before fitting is discussed together with the choice of statistic used to model the spectral shape. The best results are obtained with methods in which input data are represented by probability density functions. Application of weights, representing the coverage between the input and output bins, slightly improves the resolution of averaging.Comment: 14 pages, 13 figures, LaTeX mn2e MNRAS style, accepted for publication in MNRA

The effect of Covid-19 on consumer behavior in Poland : preliminary research results

PURPOSE: The purpose of this paper is to present the results of preliminary research on the impact of restrictions during the Covid-19 pandemic in Poland on consumer behavior. In the research we tried to demonstrate that the pandemic restrictions and austerity have changed individual consumers' behavior in their daily shopping and to what extent.DESIGN/METHODOLOGY/APPROACH: In this research we used survey research method, i.e., CAWI (Computer Assisted Web Interview) technique. The surveyed population consisted of 214 respondents. The research was conducted in the second half of 2020. The sample selection was random.FINDINGS: The results indicate that certain consumer behaviors changed during the lockdown period, indicating the impact of the Covid-19 pandemic on consumer behavior.PRACTICAL IMPLICATIONS: The research results obtained can become guidelines for changes in individual customer service. Indeed, it should be kept in mind that the change in consumer behavior under the influence of Covid-19 has three implications for management. First, business must also learn to improvise and become more flexible during a pandemic crisis. The second managerial implication is the matching of demand and supply. The third managerial effect is the occurring likelihood that consumers will not return to their old buying habits unless the technology they learn to use does not bring about significant changes in their lives.ORIGINALITY/VALUE: Presented results, complement previously conducted research on the impact of the Covid -19 pandemic on the behavior of Polish consumers. The research was designed to address, to some extent, the research gaps identified by others, in examining the effects of Covid-19 on consumer consumption and behavior.peer-reviewe

Geometry of the X-ray source 1H 0707–495

Aims. We investigate the constraints on the size and location of the X-ray source in 1H 0707–495 determined from the shape of the relativistically smeared reflection from the accretion disc. Methods. We developed a new code to model an extended X-ray source and we applied this code to all archival XMM observations of 1H 0707–495. Results. In contrast to earlier works we find that the relativistic reflection in this source is not consistent with an extended uniform corona. Instead, we find that the X-ray source must be very compact, at most a gravitational radius in size, and located at most a few gravitational radii from the black-hole horizon. A uniform extended corona produces an emissivity that is similar to a twice-broken power-law, but the inner emissivity is fixed by the source geometry rather than being a free parameter. In 1H0707–495, the reflection from the inner disc is much stronger than expected for a uniformly extended source. Including the effect of ionised absorption from the wind does not change this conclusion, but including scattered emission (and more complex absorption) from the wind can dramatically change the reflection parameters

Information on the nuclear periphery from antiprotonic atoms

In the PS209 experiments at CERN two kinds of measurements were performed: the in-beam measurement of X-rays from antiprotonic atoms and the radiochemical, off-line determination of the yield of annihilation products with mass number At — 1 (less by 1 than the target mass). Both methods give observables which allows to study the peripheral matter density composition and distribution. A comparisons of the PS209 results with the theoretical and semiempirical predictions for neutron and proton densities and with the differences Arnp of the rms radii of neutrons and protons obtained in other experiments are also presented

Association between Asymptomatic Unilateral Internal Carotid Artery Stenosis and Electrophysiological Function of the Retina and Optic Nerve

Purpose. This study was designed to assess retinal and optic nerve bioelectrical function in patients with unilateral asymptomatic but hemodynamically significant internal carotid artery stenosis (ICAS). Methods. Forty-two subjects with a diagnosis of unilateral ICAS and 34 controls were analyzed. Full-field electroretinogram (ERG), pattern electroretinogram (PERG), and pattern visual-evoked potentials, as well as optical coherence tomography and ophthalmological examination, were performed. Data analysis included eyes ipsilateral to ICAS (EIS) and eyes contralateral to ICAS (ECS). Results. Intraocular pressure was significantly decreased in EIS and ECS compared to that in the controls. In the macula, both the cube average thickness and cube volume values were significantly reduced both in EIS and ECS compared to those in the controls. Similarly, PERG P50 and N95 wave amplitudes were significantly smaller in EIS and ECS compared to those in the controls. The ERG rod b-wave and rod-cone a-wave amplitudes were decreased, and implicit times were significantly prolonged, whereas the OP wave index was reduced in EIS compared to that in the controls. No differences in IOP, OCT, or ERG and PERG parameters were identified between EIS and ECS. Conclusions. Our study demonstrated that retinal bioelectrical function is negatively affected by ICAS despite the absence of objective clinical signs and symptoms of ocular ischemia

Evaluation of aqueous flare after Descemet’s stripping endothelial keratoplasty and penetrating keratoplasty

Purpose: Evaluation of aqueous flare in patients after Descemet's Stripping Endothelial Keratoplasty (DSEK) and Penetrating Keratoplasty (PK) performed of various indications. Material and methods: In a prospective study 17 eyes in 16 patients were examined. First group consisted of 8 eyes after DSEK, second: 9 eyes after PK. The first procedure was performed of Fuch’s dystrophy - 4 eyes, bullous keratopathy – 4 eyes. The indications in the second were as follows: keratoconus – 2 eyes, corneal cicatrix without neovascularization – 3 eyes, endangering corneal perforation – 4 eyes. Examined group mean age was respectively 67 and 69 years. The overall examining time was six months after the surgery. In the paperaqueous flare was evaluated in the anterior chamber in 1st, 3rd and 6th month after keratoplasty in FM-600 Laser Flare Kowa. Abovementioned device function is based on emission and detection of light produced by diode laser. Keratoplasty was performed in general (No 9) or in local peribulbar (No 8) anaesthesia. Results: Mean aqueous flarein 1st, 3rd, and 6th month after keratoplasty is significantly lower after DSEK (14,46 +/- 4,70 ph/ms; 10,64 +/- 2,91 ph/ms; 5,98 +/- 2,53 ph/ms) in comparison with PK (18,50 +/- 5,82 ph/ms; 15,04 +/- 6,38 ph/ms; 10,68 +/- 3,83 ph/ms). In 6 months observation the mean flare value in DSEK was decreased twice in comparison with PK. Considering indication for keratoplasty mean flare measurements were respectively in 1st, 3rd and 6th month for first group: Fuchs’ dystrophy: 11,85 +/- 5,46 ph/ms; 8,28 +/- 1,80 ph/ms; 4,93 +/- 0,95 ph/ms; bullous keratopathy: 17,08 +/- 1,89 ph/ms; 13,00 +/- 1,27 ph/ms; 7,03 +/- 3,32 ph/ms. In second group respectively: keratoconus: 15,15 +/- 1,34 ph/ms; 11,95 +/- 0,49 ph/ms; 11,25 +/- 0,64 ph/ms; corneal cicatrix without neovascularization: 16,40 +/- 9,27 ph/ms; 12,13 +/- 9,85 ph/ms; 6,87 +/- 4,20 ph/ms; endangering corneal perforation: 21,75 +/- 2,54 ph/ms; 18,78 +/- 3,21 ph/ms; 13,25 +/- 1,92 ph/ms. In the analysis of indications for keratoplasty the lowest mean aqueous flare in 1st, 3rd, and 6th month after procedure was observed in the Fuchs’ dystrophy. In endangering corneal perforation mean flare values were the highest. Conclusions: Our results indirectly indicate that in examined patients after DSEK post-operative inflammatory reaction is lower than in PK. Furthermore flare values might depend on the indications for keratoplasty. The study was performed in group with various indications for keraoplasty. Further studies including protein concentration in AH after DSEK and PK performed in equal indications are needed

The MeV spectral tail in Cyg X-1 and optically-thin emission of jets

We study the average X-ray and soft gamma-ray spectrum of Cyg X-1 in the hard spectral state, using data from INTEGRAL. We compare these results with those from CGRO, and find a good agreement. Confirming previous studies, we find the presence of a high-energy MeV tail beyond a thermal-Comptonization spectrum; however, the tail is much softer and weaker than that recently published by Laurent et al. In spite of this difference, the observed high-energy tail could still be due to the synchrotron emission of the jet of Cyg X-1, as claimed by Laurent et al. To test this possibility, we study optically-thin synchrotron and self-Compton emission from partially self-absorbed jets. We develop formalisms for calculating both emission of the jet base (which we define here as the region where the jet starts its emission) and emission of the entire jet. We require the emission to match that observed at the turnover energy. The optically thin emission is dominated by that from the jet base, and it has to become self-absorbed within it at the turnover frequency. We find this implies the magnetic field strength at the jet base of B_0 prop. to z_0^4, where z_0 is the distance of the base from the black-hole centre. The value of B_0 is then constrained from below by the condition that the self-Compton emission is below an upper limit in the GeV range, and from above by the condition that the Poynting flux does not exceed the jet kinetic power. This yields B_0 of the order of ~10^4 G and the location of the jet base at ~10^3 gravitational radii. Using our formalism, we find the MeV tail can be due to jet synchrotron emission, but this requires the electron acceleration at a rather hard power-law index, p~1.3-1.6. For acceleration indices of p> 2, the amplitude of the synchrotron component is much below that of MeV tail, and its origin is likely to be due to hybrid Comptonization in the accretion flow.Comment: MNRAS, in press, 13 page