Josephson critical currents in annular superconductors with Pearl vortices

We investigate the influence of Pearl vortices in the vicinity of an edge-type Josephson junction for a superconducting thin-film loop in the form of an annulus, under uniform magnetic field. Specifically, we obtain the exact analytic formulation that allows to describe the circulating current density and the gauge invariant phase increment $\Delta\phi$ across the junction. The main properties of $\Delta\phi$ and their influence on the critical current pattern $I_c(B)$ are described quantitatively in terms of the loop's width to radius ratio $W/R$ and of the vortex position within the loop ${\bf r}_v$. It is shown that narrow loops ($W/R < 0.3$) may be well described by the straight geometry limit. However, such approximation fails to predict a number of distinctive features captured by our formulation, as the node lifting effect of the $I_c(B)$ pattern in wide loops or the actual influence of a vortex pinned at different positions.Comment: 11 pages, 8 figure

A Tracking Fiber Detector based on Silicon Photomultipliers for the Kaos Spectrometer

A tracking detector based on two meters long scintillating fibers read out by silicon photomultipliers (SiPM) is being developed for the Kaos spectrometer at the Mainz Microtron MAMI. Results from a prototype setup using 2 mm square fibers and large area SiPM readout are presented. The detection efficiency of such a combination was measured to be between 83 and 100% depending on the threshold on the SiPM amplitude. A Monte Carlo simulation based on a physical model was employed in order to extract the photon detection efficiency of the SiPM devices.Comment: Contributed to 2008 IEEE Nuclear Science Symposium, 19-25 October 2008, Dresden, German

Conjugate two-dimensional electric potential maps

Two dimensional electric potential maps based on voltage detection in conducting paper are common practice in many physics courses in college. Most frequently, students work on `capacitor-like' geometries with current flowing between two opposite electrodes. A `topographical' investigation across the embedding medium (map of equipotential curves) allows to reassure a number of physical properties. This paper focuses on some less common configurations that bear pedagogical interest. We analyze `open-geometries' with electrodes in the form of long strips with slits. They provide a natural groundwork to bring the student to complex variable methods. Aided by this, we show that shaping the conducting paper board one may analyze finite size effects, as well as some meaningful discontinuities in the measured potential. The concept of conjugate electric potentials is exploited. Equipotentials and electric field lines acquire interchangeable roles and may be obtained in complementary `dual' experiments. A feasible theoretical analysis based on introductory complex variables and standardized numerics gives a remarkable quantification of the experimental results.Comment: 15 pages, 8 figure

Norms and Institutions of the Congress of Vienna – 200 Years Later

The conference “Ideas, norms and institutions of the Congress of Vienna – 200 years later” took place in Warsaw on 15 and 16 October 2015. It was organised by the International Law Association – Polish Group. The aim of the conference was a legal reflection (mostly international law) on the legacy of the Congress of Vienna. The intention of the organisers was to study the “present day” and not the past, but to do so by looking at continuity with the past. The starting point was the hypothesis that the ideas, norms and institutions created by the participants of the Congress are still present in international law, either in their original formula, or as more modern ideas, or as norms and institutions

An asymmetrical fenestration of the basilar artery coexisting with two aneurysms in a patient with subarachnoid haemorrhage: case report and review of the literature

The vertebrobasilar system is a part of the cerebral arterial circle (circle of Willis), which forms the collateral circulation of the brain. A 75-year-old Caucasian female was admitted to hospital because of a strong headache radiating to the neck. On the basis of a neurological examination, the patient was classified into group III of the Hunt and Hess scale. Subarachnoid haemorrhage and 2 aneurysms of the cerebral arteries were diagnosed during multidetector 64-row computed tomography and angiography. An asymmetrical fenestration of the proximal part of the basilar artery was also observed. The bleeding aneurysm locating at anterior communicating artery was diagnosed and clipped surgically by right fronto-parietal craniotomy. The second aneurysm was located just after the junction of the vertebral arteries on the wall of the basilar artery. The presented case firstly illustrates the asymmetric fenestration of the proximal part of the basilar artery coexisting with subarachnoid haemorrhage and 2 aneurysms of brain arteries. Such observation should increase diagnostic attention in the detection of possible associated aneurysms and can help in preventing complications during all endovascular treatment procedures

Excessive brain atrophy in patients with severe aortic stenosis

Purpose: To assess the prevalence of the neuroradiological indices of brain atrophy in patients with severe aortic valve stenosis (AS) in magnetic resonance imaging (MRI) with particular emphasis on the assessment of atrophy areas typical of cerebral small vessel disease (CSVD). Material and methods: The group of 34 patients (age 60-90 years, 17 women and 17 men) with severe AS and 50 healthy controls (age 61-85 years, 29 women and 21 men) underwent MRI brain examinations, which were analysed for the neuroradiological indices of brain atrophy. Results: A slight but statistically significant age difference was found between the study and control groups - about 3 years on average (p = 0.040). Differences between total brain volumes in both the groups did not show statistical significance. In a comparative analysis of the main brain compartments, a statistically significant difference was found only in the volumetry of cerebral hemispheres for both the groups: mean volume of cerebral hemispheres in patients with severe AS was 884.46 cm³, while it was 17 cm³ bigger in the volunteer group, reaching 901.80 cm³ on average (p = 0.043). Comparison of the volumetry of the other major and minor regions and structures according to the clinical and anatomical division revealed statistically non-significant differences. No statistically significant relationships were observed concerning structures correlated with CSVD. Conclusions: Neuroradiological indices of the brain atrophy do not provide an unequivocal distinction in patients with severe AS. Most observations imply that brain atrophy in patients with severe AS is primarily a consequence of physiological ageing of the brain

The influence of atherosclerotic abdominal aorta on the shape of duplicated inferior vena cava: its potential clinical implications and vascular complications

Duplication of the inferior vena cava (IVC) is a congenital condition where there are 2 large vessels: right IVC (RIVC) and left IVC (LIVC) on both sides of the abdominal aorta. Here, we present 2 cases of duplicated inferior cava coexisting with rare morphology of left gonadal (ovarian/testicular) vein. Both were observed during multidetector 64-row computer tomography. In first case atherosclerotic, tortuous abdominal aorta models both inferior venae cavae. The shape of veins were more- (RIVC) and less-arcuate (LIVC). Two years ago, the patient had been diagnosed with pulmonary thromboembolism. In second case abdominal aortic aneurysm models both large veins. The RIVC has a highly right-arcuate shape, while the LIVC has a less left-arcade shape. Our observation would seem to be especially important, because the tortuous abdominal aorta changes the shape of both IVC, and may predispose them for thrombosis formation. The presented report precisely describes the topography and measurements of the vessels in the retroperitoneal area. The literature concerning this anomaly, potential clinical implications and vascular complications are reviewed and the possible practical aspects are discussed. A familiarity with the anatomy of the most common types of venous anomalies is crucial for all surgeons, urologists and oncologists to reduce the risk of severe haemorrhage during all abdominal procedures

Magnetic resonance imaging assessment of cerebral small vessel disease intensification in patients with severe aortic valve stenosis

Purpose: To assess the prevalence of the neuroradiological indices of cerebral small vessel disease (CSVD) in patients with severe aortic valve stenosis (AS) in magnetic resonance imaging (MRI). Material and methods: 34 patients (age 60-90 years, 17 women and 17 men) with severe AS and 50 healthy controls (age 61-85 years, 29 women and 21 men) underwent MRI brain examinations, which were analysed for the neuroradiological indices of CSVD: hyperintensities in periventricular white matter (PVWM) and deep white matter (DWM), enlarged perivascular spaces (ePVS), lacunar strokes, and cerebral microbleeds (CMBs). Results: PVWM hyperintensities were found in 46% of volunteers and was significantly lower (p = 0.027), corresponding to AS patients (80%), the density of lesions was higher in the AS group than in controls (p = 0.019). DWM hyperintensities were found more often in AS patients (76%) than in controls (66%) (p = 0.303), but the densities were similar in both groups. Lacunar strokes were found in 35% of AS patients and 16% of controls (p = 0.042). The average number of lacunar strokes per person was 0.9 in the AS group and 0.3 in the controls (p = 0.035). The AS group showed higher variance in the number of strokes: SD = 1.96 vs. SD = 1.06 in controls. Both prevalence and density of the ePVS and CMBs did not differ significantly between the groups. Conclusions: Neuroradiological indices of the vascular disease do not provide an unequivocal clue to the pathogenesis of CSVD in patients with severe AS. Most observations imply that CSVD is primarily a consequence of cerebral hypoperfusion caused by AS

The United Nations system from the Polish perspective. Conference report Warsaw, 13–14.10. 2016

The conference “The United Nations system from the Polish perspective” took place in Warsaw on 13 and 14 October 2016. It was organised by the International Law Association – Polish Group. The aim of the conference was to analyse the universal international order, its central role in the United Nations, and the institutions of the UN system from the Polish perspective (this perspective means both the place of Poland in the institutionalised order, and the perception of the phenomenon by Polish lawyers)..