Propagators weakly associated to a family of Hamiltonians and the adiabatic theorem for the Landau Hamiltonian with a time-dependent Aharonov-Bohm flux

We study the dynamics of a quantum particle moving in a plane under the influence of a constant magnetic field and driven by a slowly time-dependent singular flux tube through a puncture. The known adiabatic results do not cover these models as the Hamiltonian has time dependent domain. We give a meaning to the propagator and prove an adiabatic theorem. To this end we introduce and develop the new notion of a propagator weakly associated to a time-dependent Hamiltonian.Comment: Title and Abstract changed, will appear in Journal of Mathematical Physic

Implications of spatial distribution of rockfall reconstructed by dendrogeomorphological methods

Rockfall is a dangerous geomorphological process. The prediction of potentially threatened areas requires thorough reconstruction of spatial rockfall activity. Dendrogeomorphic methods allow precise determination of both temporal and spatial occurrences of rockfall without the necessity of long-term monitoring. At the case-study site of Taraktash, located among southern slopes of the Crimean Mountains, 114 Crimean pine trees (Pinus nigra ssp. pallasiana) were sampled on a talus slope located under a 150 m high rockwall. Based on their age, the trees were divided into two distinct groups (young and old trees). Considerable disturbance in the age structure of the trees on the talus was probably caused by a series of strong earthquakes. Major differences were identified in the ability of young and old trees to record a rockfall event. We found that in the first decades of their growth, the ability of the studied P. nigra to record rockfall events gradually increased. The trees showed the highest sensitivity at the age of 80 to 90 yr; after that age their sensitivity gradually decreases. Two indicators were selected for the spatial reconstruction of rockfall events (the number of rockfall events per tree and recurrence interval). The highest activity was identified on the talus using selected indicators

Higher prevalence of smoking and lower BMI, waist circumference, cholesterol and triacylglyceride levels in Prague's homeless compared to a majority of the Czech population

BACKGROUND: Homeless people have higher morbidity and mortality rates than the general population. Research has shown that cardiovascular disease is the leading cause of death in older homeless adults. This study was undertaken to describe the prevalence of cardiovascular risk factors in the homeless population in Prague. METHODS: Data was obtained from a cross-sectional study carried out in 2003. Body mass index (BMI), waist circumference (WC), total cholesterol (TC), triacylglycerides (TAG) and smoking habits were assessed. The homeless participants in the study were recruited from a homeless center run by a Prague charitable organization called Naděje ("Hope") and at Prague's main railway station. Most participants were assessed at the Naděje center (134 persons) while the rest were assessed at Prague's Bulovka University Hospital (67 persons). RESULTS: A total of 201 homeless (174 males and 27 females) aged 19 – 70 years were examined. Mean values of BMI, WC, TC and TAG in homeless men and women were within normal limits. Compared with the majority of the Czech population, the homeless had significantly lower mean levels of TC and TAG and lower BMI and WC values. When compared to the majority of the Czech population, the incidence of smoking among the homeless was significantly higher. Among smokers in both populations, no differences were found in the number of cigarettes smoked per day. CONCLUSION: Classical cardiovascular risk factors such as TC, TAG, BMI and WC, are significantly lower in Prague's homeless minority than in the majority of the Czech population. However, the prevalence of smoking is much higher in the homeless population

Environmental magnetism as a dating proxy for recent overbank sediments of (peri-)industrial regions in the Czech Republic and UK

Twenty five floodplain sediment profiles from seven rivers in eastern Czech Republic and three in north west England were collected to examine the hypothesis that magnetic enhancement in recent sediments is predominantly of anthropogenic origin and that magnetic parameters can be used as a dating proxy reflecting changes in intensity of industry sources over time. Natural sources of magnetic enhancement were excluded and anthropogenic enhancement was identified as exhibiting elevated values of χlf, ARM, SIRM, SIRM/χ and S-ratios with lowvalues of χfd%. Magnetic spherules, typically formed through fossil fuel combustion processes, were observed by scanning electron microscopy (SEM) in these sediments. To assess the potential of magnetic parameters as a chronometer, the approach was compared with frequently used dating techniques: concentrations of heavy metals and 137Cs.The floodplain profileswere divided to three groups according to the characteristics of their trends with depth in magnetic parameters; χlf in particular, and the suitability of magnetic properties as a dating proxy. Group 1, which included the majority of the profiles, exhibited magnetic enhancement in the upper part of its profiles and a single maximum in χlf. This group exhibited a clear suitability for our proposed ‘magnetic dating’ as the magnetic record reflected the industrial history of the region and was aligned with the chronologies of the other dating techniques. Profiles magnetically enhanced throughout their depth and lacking any clear trend comprised group 2; here a mineral magnetic approach to dating was limited as the magnetic signal was diluted by a high sedimentation rate or impacted by local anthropogenic factors. All profiles from England were included in group 3 because their magnetic depth profiles were influenced by natural sources of magnetic particles or specific sedimentary conditions, and a longer industrial history and thus needed an individual interpretation. However, they still reflected the regional deposition history of industrial sources of ferrimagnetic particles. Overall, magnetic parameters proved to be an efficient dating proxy with potential for recently aggrading river

Investigation of recent catastrophic landslides in the flysch belt of Outer Western Carpathians (Czech Republic): progress towards better hazard assessment

Rapid snow melting and intense precipitation triggered and reactivated tens of mostly shallow landslides in the eastern part of the Czech Republic at the turn of March and April 2006. This area is build up by highly fractured flysch rock units with variable content of sandstones and claystones. The landslide complex at Hluboče (Brumov-Bylnice town) is composed of shallow translational (up to 10 m thick) as well as deep-seated (up to 20 m thick) rotational landslides, which generated a catastrophic earthflow at their toe. This earthflow destroyed three buildings, the access road and caused total loss of about 350 000 EUR. Detailed field investigation, review of the archive sources and interviewing of local inhabitants allowed brief description of slope movement history prior the catastrophic event as well as detailed reconstruction of slope failure mechanisms during the main movement activity (3–4 April 2006). This information, along with the detailed description of the passive as well as active causative factors (structural and morphologic settings) can contribute towards better identification of potentially dangerous slope failures in the study region

Folia Biologica (Praha) 51, 159-165 (2005) Original Articles Immune Characterization of the Lewis Rats Inoculated with K2 Sarcoma Cell Line and Newly Derived R5-28 Malignant Cells ( rat sarcoma / malignancy / myeloid cells / splenomegaly / natural killer

Abstract. Sarcoma is a relatively rare malignant disease with high mortality, bad prognosis and response to conventional therapy. Two possible models of this disease were tested: the K2 rat sarcoma cell line, which was described previously, and the new rat R5-28 cell line derived from a spontaneously growing rat neoplasm with sarcoma morphology. While all rats inoculated with K2 cells developed tumours at 22 th -25 th day after inoculation (D = 22-25), only 60%-75% of R5-28-inoculated rats were affected by tumours. The frequency and progress of the disease depended on the number of inoculated cells. No metastases were detected in both cases. All affected animals showed large splenomegaly. A possible response of some immune system components to tumours was tested. No tumourinfiltrating lymphocytes were revealed in the tumour tissue. Anti-tumour antibodies were not found in tumour-bearing animal sera. Appropriate changes in peripheral blood lymphocyte subsets were explored. While the relative numbers of both NK cells and Tc were impaired, no changes were noted in numbers of CD4 + CD8 -T helper cells. Leukocytosis with highly increased numbers of CD11b + myeloid cells displaying variable expression of CD4 was detected in terminal stages of the disease. Sarcomas are rare but aggressive tumours of mesenchymal origin. They consist of poorly differentiated or undifferentiated tumour cells. On that account sarcomas compose several heterogeneous histological groups with different clinical markers. Prognosis is usually bad and standard therapies remain limited. Several animal models of sarcoma are known, one of them was described by Contrary to other tumours such as melanoma or colon carcinoma, sarcomas are not very well defined from the immunological point of view, particularly due to the variety of differentiation stages of tumour cells and therefore wide spectra of expressed antigens. It was shown recently that more than 70% of human sarcomas bear tumour testicular antigens NY-ESO-1 and SP110 To identify host-tumour interactions and immune system changes in this cancer disease we utilized the Lewis rat sarcoma model. We selected the low-malignant K2 cells to develop subcutaneous tumours in experimental animals. Tumour growth, metastatic potential and abundance of immune cells in peripheral blood were monitored. We also included in this stud