scholarly journals Microvariability of S5 0716+714, a γ-Ray Blazar

1998 ◽  
Vol 188 ◽  
pp. 442-443 ◽  
Author(s):  
R. Nesci ◽  
E. Massaro ◽  
M. Maesano ◽  
F. Montagni ◽  
F. D'Alessio ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Synchrotron Radiation ◽  
General Scheme ◽  
Plasma Jet ◽  
Line Of Sight ◽  
First Case ◽  
Γ Ray ◽  
Geometrical Effects ◽  
High Level ◽  
Different Time Scales

Like many radio-selected blazars, 0716+714 shows a high level of variability on different time scales, as short as a few days (e.g. Wagner et al 1996, Ghisellini et al. 1997). The mechanism of the emission in the optical band, in the general scheme of a relativistic plasma jet highy collimated toward the observer, is generally believed to be synchrotron radiation from electrons in a strong magnetic field. Our monitoring of S5 0716+714 is aimed to clarify whether the flux variations are chromatic or achromatic. In the first case, one could guess that variations in the spectrum of the injected electrons are responsible for the flux variations; in the second case, geometrical effects like small changes in the angle between the jet and the line of sight could be more likely (Wagner et al. 1993).

scholarly journals The effect of simplifications of a numerical mesh on the results of electromagnetic analysis of the Nuclotron-type cable

2018 ◽  
Vol 177 ◽  
pp. 08004
Author(s):  
Łukasz Tomków
Keyword(s):  
Magnetic Field ◽  
Electric Current ◽  
Current Density ◽  
Electric Current Density ◽  
Electromagnetic Analysis ◽  
First Case ◽  
Single Region ◽  
The Magnetic Field

The model of a single Nuclotron-type cable is presented. The goal of this model is to assess the behaviour of the cable under different loads. Two meshes with different simplifications are applied. In the first case, the superconductor in the cable is modelled as single region. Second mesh considers individual strands of the cable. The significant differences between the distributions of the electric current density obtained with both models are observed. The magnetic field remains roughly similar.

scholarly journals Broadband Linear Polarization in Ap Stars

1993 ◽  
Vol 138 ◽  
pp. 305-309
Author(s):  
Marco Landolfi ◽  
Egidio Landi Degl’Innocenti ◽  
Maurizio Landi Degl’Innocenti ◽  
Jean-Louis Leroy ◽  
Stefano Bagnulo
Keyword(s):  
Magnetic Field ◽  
Circular Polarization ◽  
Linear Polarization ◽  
Rotation Axis ◽  
Spectral Lines ◽  
Line Of Sight ◽  
Long Time ◽  
Rotating Star ◽  
Ap Stars ◽  
The Magnetic Field

AbstractBroadband linear polarization in the spectra of Ap stars is believed to be due to differential saturation between σ and π Zeeman components in spectral lines. This mechanism has been known for a long time to be the main agent of a similar phenomenon observed in sunspots. Since this phenomenon has been carefully calibrated in the solar case, it can be confidently used to deduce the magnetic field of Ap stars.Given the magnetic configuration of a rotating star, it is possible to deduce the broadband polarization at any phase. Calculations performed for the oblique dipole model show that the resulting polarization diagrams are very sensitive to the values of i (the angle between the rotation axis and the line of sight) and β (the angle between the rotation and magnetic axes). The dependence on i and β is such that the four-fold ambiguity typical of the circular polarization observations ((i,β), (β,i), (π-i,π-β), (π-β,π-i)) can be removed.

TIGHT-BINDING MODEL FOR THE QUANTUM LADDER IN A MAGNETIC FIELD

1996 ◽  
Vol 10 (28) ◽  
pp. 3827-3856 ◽  
Author(s):  
KAZUMOTO IGUCHI
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Tight Binding ◽  
Critical Value ◽  
Tight Binding Model ◽  
Binding Model ◽  
First Case

A tight-binding model is formulated for the calculation of the electronic structure and the ground state energy of the quantum ladder under a magnetic field, where the magnetic flux at the nth plaquette is given by ϕn. First, the theory is applied to obtain the electronic spectra of the quantum ladder models with particular magnetic fluxes such as uniform magnetic fluxes, ϕn=0 and 1/2, and the staggered magnetic flux, ϕn= (−1)n+1ϕ0. From these, it is found that as the effect of electron hopping between two chains—the anisotropy parameter r=ty/tx—is increased, there are a metal-semimetal transition at r=0 and a semimetal–semiconductor transition at r=2 in the first case, and metal-semiconductor transitions at r=0 in the second and third cases. These transitions are thought of as a new category of metal-insulator transition due to the hopping anisotropy of the system. Second, using the spectrum, the ground state energy is calculated in terms of the parameter r. It is found that the ground state energy in the first case diverges as r becomes arbitrarily large, while that in the second and third cases can have the single or double well structure with respect to r, where the system is stable at some critical value of r=rc and the transition between the single and double well structures is associated with whether tx is less than a critical value of txc. The latter cases are very reminiscent of physics in polyacetylene studied by Su, Schrieffer and Heeger.

scholarly journals Thermalization of synchrotron radiation from field-aligned currents

1988 ◽  
Vol 6 (3) ◽  
pp. 493-501 ◽  
Author(s):  
William Peter ◽  
Anthony L. Peratt
Keyword(s):  
Magnetic Field ◽  
Synchrotron Radiation ◽  
Energy Density ◽  
Radiation Spectrum ◽  
Axial Magnetic Field ◽  
Three Dimensional ◽  
Synchrotron Emission ◽  
Microwave Background ◽  
Strong Function ◽  
Current Filaments

Three-dimensional plasma simulations of interacting galactic-dimensioned current filaments show bursts of synchroton radiation of energy density 1·2 ×10−13 erg/cm3 which can be compared with the measured cosmic microwave background energy density of 1·5 × 10−13 erg/cm3. However, the synchrotron emission observed in the simulations is not blackbody. In this paper, we analyze the absorption of the synchrotron emission by the current filaments themselves (i.e., self-absorption) in order to investigate the thermalization of the emitted radiation. It is found that a large number of current filaments (>1031) are needed to make the radiation spectrum blackbody up to the observed measured frequency of 100 GHz. The radiation spectrum and the required number of current filaments is a strong function of the axial magnetic field in the filaments.

Study of the glow dynamics in a laser-produced plasma jet expanding across the magnetic field

2011 ◽  
Vol 37 (9) ◽  
pp. 802-806 ◽  
Author(s):  
A. V. Bessarab ◽  
G. A. Bondarenko ◽  
S. G. Garanin ◽  
N. V. Zhidkov ◽  
I. N. Nikitin ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Plasma Jet ◽  
Laser Produced Plasma ◽  
The Magnetic Field

Jewish Holiday “Tu Bishvat” or Two Cases of Small Bowel Obstruction with Dried Apricot

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kukeev I ◽  
◽  
Replyansky I ◽  
Czeiger D ◽  
Atias S ◽  
...  
Keyword(s):  
Small Bowel ◽  
Small Bowel Obstruction ◽  
Bowel Obstruction ◽  
Gastric Bypass Surgery ◽  
Surgical Removal ◽  
Cellulose Content ◽  
Lead Point ◽  
First Case ◽  
Dried Fruit ◽  
High Level

Introduction: Small bowel obstruction caused by bezoars is rare. One of the causes of phytobezoars is dried fruits. We present two cases of small bowel obstruction caused by dried apricots during Jewish holiday “Tu BiShvat”. Case Presentation: Two men, 54 and 86 years old hospitalized with acute abdomen attributed to small bowel obstruction. In the first case - intoxicated patient, due to suspicion of mesenteric ischemia underwent laparotomy. A lead point caused obstruction was found and after enterotomy whole dried apricot was removed. The patient swallowed it whole three days before hospitalization. In the second case, edentulous patient with small bowel obstruction and peritonitis underwent laparotomy. The cause of obstruction was a dried apricot swallowed whole by the patient. Discussion: Presentation of bezoar with features of acute surgical abdomen is extremely rare, accounting for only 1% of the patients. The expansion of phytobezoar that is high in cellulose content can absorb a large amount of fluid causing an obstruction of the small bowel. The treatment of small bowel obstruction caused by bezoars varies from dissolving with cellulase, papain and even Coca-Cola, followed by endoscopic and surgical removal. Conclusion: A high level of suspicion needs to exist in the presence of a history of eating dried fruit, which can cause gastrointestinal obstruction. Especially on background gastric bypass surgery and inadequate mastication.

scholarly journals A Case of Multiple Posterior Intercostal Artery Common Trunks in Conjunction with Additional Arterial Variations

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Nicholas R. Fanselow ◽  
Nolan Wallace ◽  
Daniel Sehi ◽  
Lokesh Coomar ◽  
John Martin ◽  
...  
Keyword(s):  
Vertebral Artery ◽  
Intercostal Space ◽  
Thoracic Wall ◽  
Thoracic Cavity ◽  
Arterial Variation ◽  
Arterial Variations ◽  
First Case ◽  
Male Cadaver ◽  
The Right ◽  
High Level

Several thoracic vasculature variations were observed in an 81-year-old male cadaver during routine dissection. These included 5 common trunks of posterior intercostal arteries, a descending branch of the right vertebral artery, and atypical neurovascular relationships within intercostal spaces. On the right side, two common trunks of posterior intercostal arteries were observed supplying the 4th-7th intercostal spaces and 9th-11th intercostal spaces, respectively. There was also a small accessary branch supplying the 9th intercostal space. The first three posterior intercostal spaces on the right were supplied by a descending branch of the vertebral artery. On the left side, three common trunks of posterior intercostal arteries were encountered, supplying intercostal spaces 3-5, 6-7, and 11 plus the subcostal space. An atypical neurovascular relationship was observed in the right 6th intercostal space, as well as the left 2nd, 3rd, and 6th intercostal spaces. This is the first case report that presents 5 common trunks of posterior intercostal arteries, as well as common trunks in conjunction with other arterial variation in the posterior thoracic wall. These variations carry a high level of clinical significance and may be helpful in guiding decision-making related to surgical procedures related to the posterior thoracic cavity and spine.

Sign in / Sign up

Export Citation Format

Share Document