Berry phase in magnetic systems with point perturbations

We study a two-dimensional charged particle interacting with a magnetic field, in general non-homogeneous, perpendicular to the plane, a confining potential, and a point interaction. If the latter moves adiabatically along a loop the state corresponding to an isolated eigenvalue acquires a Berry phase. We derive an expression for it and evaluate it in several examples such as a homogeneous field, a magnetic whisker, a particle confined at a ring or in quantum dots, a parabolic and a zero-range one. We also discuss the behavior of the lowest Landau level in this setting obtaining an explicit example of the Wilczek-Zee phase for an infinitely degenerated eigenvalue.Comment: LaTeX, 26 page

Eye spectral sensitivity in fresh- and brackish-water populations of three glacial-relict Mysis species (Crustacea) : physiology and genetics of differential tuning

Absorbance spectra of single rhabdoms were studied by microspectrophotometry (MSP) and spectral sensitivities of whole eyes by electroretinography (ERG) in three glacial-relict species of opossum shrimps (Mysis). Among eight populations from Fennoscandian fresh-water lakes (L) and seven populations from the brackish-water Baltic Sea (S), L spectra were systematically red-shifted by 20-30 nm compared with S spectra, save for one L and one S population. The difference holds across species and bears no consistent adaptive relation to the current light environments. In the most extensively studied L-S pair, two populations of M. relicta (L (p) and S (p)) separated for less than 10,000 years, no differences translating into amino acid substitutions have been found in the opsin genes, and the chromophore of the visual pigments as analyzed by HPLC is pure A1. However, MSP experiments with spectrally selective bleaching show the presence of two rhodopsins (lambda (max) a parts per thousand 525-530 nm, MWS, and 565-570 nm, LWS) expressed in different proportions. ERG recordings of responses to "red" and "blue" light linearly polarized at orthogonal angles indicate segregation of the pigments into different cells differing in polarization sensitivity. We propose that the pattern of development of LWS and MWS photoreceptors is governed by an ontogenetic switch responsive to some environmental signal(s) other than light that generally differ(s) between lakes and sea, and that this reaction norm is conserved from a common ancestor of all three species.Peer reviewe

Urceni rezidualni nemoci u leukemie s vlasatymi bunkami

Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Electrical condition monitoring techniques for low-voltage cables used in nuclear power plants

In this paper, dielectric spectroscopy is adapted to investigate the dielectric response, in the frequency range 10-2-106Hz, of a low-voltage cable for nuclear power plants. Cable samples were aged under accelerated stress conditions up to an equivalent aging time of 60 years. The aging procedure consisted of two phases: thermal aging by means of high temperature followed by gamma-irradiation at room temperature. Dielectric spectroscopy has been adapted to measure the dissipation factor Tan(\u3b4) of inner insulation and outer sheath. A significant reduction of Tan(\u3b4) can be observed in the frequency range 101-104Hz, indicating that accelerated aging process mainly affects the dipolar polarization. Furthermore, the shape of the dielectric response presents a global minimum which shifts to lower frequency as the aging time increases. Experimental results show that the frequency in correspondence of this minimum value, as well as Tan(\u3b4) at the reference frequency of 100 Hz, can be used as aging indicator

BETTER OUTCOME OF HIGH-DOSE CEFTAZIDIME IN HEMATO – ONCOLOGICAL PATIENTS WITH INFECTIONS CAUSED BY EXTENSIVELY DRUG-RESISTANT PSEUDOMONAS AERUGINOSA

Background: P. aeruginosa sepsis in immunocompromised patients is serious complication of cancer treatment, especially in case of XDR pathogen. The purpose of the study is to evaluate the efficacy of high-dose ceftazidime in treatment of XDR P. aeruginosa infection and to compare it with the conventionally treated cohort in hemato-oncological patients. Methods: We identified 27 patients with XDR P. aeruginosa infection during the 2008-2018 period, 16 patients served as a conventionally treated cohort with antipseudomonal beta-lactam antibiotic in standard dose (cohort A), and 11 patients were treated with high-dose ceftazidime (cohort B).  Most of the patients were neutropenic and under active treatment for their cancer in both cohorts. Results: Mortality and related mortality were statistically significantly better for cohort B compared to cohort A,  it was  18.2% and 9.1% for cohort B and 68.8% and 68.8% for cohort A, respectively. More patients in cohort A needed mechanical ventilation and renal replacement therapy, 75% and 50% for cohort A and 27.3% and 9.9% for cohort B, respectively.  It corresponded well with the worst SOFA in cohort A in comparison to cohort B, 16 versus 7 respectively. Reversible neurotoxicity was seen only in two patients in cohort B. Conclusion: Ceftazidime in high doses is a very potent ATB for the treatment of XDR P. aeruginosa infections in neutropenic cancer with acceptable toxicity

Saprochaete clavata Invasive Infections - A New Threat to Hematological-Oncological Patients

Background Saprochaete clavata (formerly Geotrichum clavatum, now proposed as Magnusiomyces clavatus) is a filamentous yeast-like fungus that has recently been described as an emerging pathogen mostly in patients with acute leukemia. Methods This is a retrospective study of patients diagnosed with proven and probable S. clavata infection at the University Hospital, Hradec Kralove, Czechia between March 2005 and December 2017. Previous cases were identified from the literature and FungiScope (R) database. Results Six new cases (5 females, 1 male) of blood-stream S. clavata infections at the hemato-oncological department were described including epidemiological data of additional 48 patients colonized with the species. Overall, 116 strains of S. clavata were isolated from different clinical specimens of 54 patients; most of them belonged to the respiratory tract (60.3%). S. clavata was the most frequent species among arthroconidial yeasts (Trichosporon, Galactomyces, Magnusiomyces) recovered from the blood. All our patients with S. clavata infection had profound neutropenia, a central venous catheter, broad-spectrum antibiotics and antifungal prophylaxis; four had a history of a biliary tract system disease. The diagnosis was based on a positive blood culture in all patients. Four patients died of multiorgan failure and sepsis despite treatment with lipid-based amphotericin B and/or voriconazole. From the literature and FungiScope database, 67 previous cases of S. clavata infections were evaluated in context of our cases. Conclusion Saprochaete clavata infection represents a life-threatening mycosis in severely immunocompromised patients. The successful outcome of treatment seems to be critically dependent on the early diagnosis and the recovery of underlying conditions associated with immune dysfunction or deficiency