Ballistic (precessional) contribution to the conventional magnetic switching

We consider a magnetic moment with an easy axis anisotropy energy, switched by an external field applied along this axis. Additional small, time-independent bias field is applied perpendicular to the axis. It is found that the magnet's switching time is a non-monotonic function of the rate at which the field is swept from "up" to "down". Switching time exhibits a minimum at a particular optimal sweep time. This unusual behavior is explained by the admixture of a ballistic (precessional) rotation of the moment caused by the perpendicular bias field in the presence of a variable switching field. We derive analytic expressions for the optimal switching time, and for the entire dependence of the switching time on the field sweep time. The existence of the optimal field sweep time has important implications for the optimization of magnetic memory devices

Physics of low and intermediate spin states of atomic nuclei in the mass A ~ 160 region

The nuclear landscape provides possibly the richest set of data that can be collected for quantum systems, displaying many varying features. The lack of a complete nuclear theory has resulted in a fragmentation of the theories used to describe isolated sections of observables in the landscape of nuclear excitations. A recent model proposed that a tetrahedral deformation could explain observed low-lying, negative parity bands characterized by a lack of in-band electromagnetic transitions. For this work, experimental data has been collected specifically to quantify the intensities of the "missing" in-band transitions for several nuclei in the mass 160 region (156 68Er, 160 68Er and 158 66Dy). While these in-band transitions appear suppressed, it was possible to not only observe some of these transitions, but to quantify the suppression, which indicate a consistency within the band structure between low and medium spin states. An order of magnitude difference was observed in the B(E2)/B(E1) branching ratios between the odd-spin and the even-spin octupole vibrational bands in ¹⁵⁸Dy and ¹⁶⁰Er. This difference is consistent with that reported in other nuclei in the region, which is indicative of some shared reason for this behaviour. The theoretical aspect of this work tries to explain the observed anomalies in terms of the Random Phase Approximation model. Results of calculations suggest that in the intrinsic frame, the negative signature collective modes will have significantly stronger absolute B(E1) rates than the positive signature band partners. By considering a quadrupole deformation of these vibrational states as consistent with the ground state band, the B(E2) rates can be estimated, and the theoretical value for the B(E2)/B(E1) branching ratio is shown to be qualitatively consistent with experimental observations. From this we conclude that the negative parity vibrational bands in the mass 160 region are likely low-K octupole bands, and not tetrahedrally deformed structures

Development of a freeze-out surface for 3+1 dimensional hydrodynamics

Includes bibliographical references (leaves 65-67).A review of a macroscopic description of heavy ion collisions is presented, with focus on hydrodynamics. The various models are discussed and motivation is provided for using full 3+ 1 dimensional hydrodynamics. Numerical freeze-out is then discussed, and a numerical development of the freeze-out hypersurface is presented. Possible algorithmic extensions are described

Cellular and cytokine immunoregulation in patients with chronic obstructive pulmonary disease and bronchial asthma.

BACKGROUND: Different forms of chronic airway inflammation may involve diverse pathogenic elements. In general, deficient defence response is a feature of chronic obstructive pulmonary disease (COPD), whereas distorted immunoregulatory mechanisms lead to development of asthmatic symptoms. In addition to diverse effector mechanisms, the cellular and humoral elements participating in the development of immune response may appear to be different in COPD and bronchial asthma (BA) patients. AIMS: To evaluate the immunoregulatory properties of T cells and monocytes in cultures of peripheral blood mononuclear cells (PBMC) and to determine the chosen cytokine profiles in COPD and BA patients. METHODS: The microcultures of PBMC from COPD and BA patients were assessed for the T-cell response to mitogens, saturation of interleukin (IL)-2 receptors, T-cell suppressive activity and monokine influence on lymphocyte proliferation. Concomitantly, the cytokine (IL-1beta, interleukin-1 receptor antagonist, tumour necrosis factor-alpha, IL-4, IL-6, IL-8) concentrations were determined in the serum, the broncho-alveolar lavage fluid and in the culture supernatants. RESULTS: The T-lymphocyte reactions (response to phytohaemagglutinin, IL-2 receptor saturation, suppressive activity) were lower in BA patients than in COPD patients. Reversely, the immunogenic activity of monocytes (IL-1beta versus IL-1ra production) was higher in BA patients than in COPD patients. The highest values of cytokine concentrations were found in the culture supernatants. The concentrations of tumour necrosis factor-alpha, IL-4, IL-6 and IL-8 were significantly higher and the concentration of IL-1ra was lower in BA patients than in COPD patients. CONCLUSION: The assessments of cellular immunoregulatory properties and cytokine profiles in the cultures of blood mononuclear cells may prove helpful for diagnostic and therapeutic discrimination between BA and COPD patients

Effect of 3-year education in the Main Fire Service School on the fitness level of students

Introduction and objective The aim of the study was to determine changes in the fitness level among students of the Main Fire Service School during 3-year’s education. Material and Methods A total of 75 male and 5 female students took part in the study. Fitness level measurements were carried out before beginning the studies (Measurement 0) and after the 1st, 2nd and 3rd years at the school (Measurement 1, 2, 3). The following tests were performed to estimate level of physical fitness for men: pull-ups on a bar, a 50 m sprint and 1,000 m run, and for women: sit-ups, medical ball (2 kg) throw from above the head and a 4 x10 m shuttle run. Results General fitness level (average number of points from 3 attempts) of the male and female students improved. Improvement of fitness level between Measurement 0 (male students 60.3p.±7.58; female students 61.60p.±3.08), and Measurements 1, 2, 3 (men 64.59p.±6.87; 64.41p.±7.17; 64.03p.±7.65 and women 68.40p.±1.99; 66.67p.±2.36; 68.87±1.87 respectively), was found. The same relationship was found while analysing results of individual competitions. Only speed endurance (anaerobic-aerobic) assessed during Measurement 0 at 64.03p.±10.23, decreased after the 1st year at the school (Measurement 1 – 59.29p.±14.14) and remained on the same level during Measurements 2 and 3 (60.25p.±11.20 and 58.56p. ±12.80, respectively). Conclusions Speed endurance (anaerobic-aerobic) is a capability which decreased among the students in the subsequent years. Because this capability highly correlates with activities that a fire-fighter will perform during rescue operations, it should be treated as a matter of priority during physical education classes in the Main Fire Service School

Organic Geochemistry and Petrology of Oil Source Rocks, Carpathian Overthrust Region, Southeastern Poland — Implications for Petroleum Generation

The organic matter rich Oligocene Menilite black shales and mudstones are widely distributed in the Carpathian Overthrust region of southeastern Poland and have excellent hydrocarbon generation potential, according to TOC, Rock-Eval, and petrographic data. Extractable organic matter was characterized by an equable distribution of steranes by carbon number, by varying amounts of 28,30-dinor-hopane, 18α(H)-oleanane and by a distinctive group of C24 ring-A degraded triterpanes. The Menilite samples ranged in maturity from pre-generative to mid-oil window levels, with the most mature in the southeastern portion of the study area. Carpathian petroleum samples from Campanian-Oligocene sandstone reservoirs were similar in biomarker composition to the Menilite rock extracts. Similarities in aliphatic and aromatic hydrocarbon distributions between petroleum asphaltene and source rock pyrolyzates provided further evidence genetically linking Menilite kerogens with Carpathian oils

Crystal Nucleation by Laser-Induced Cavitation\ud

High-speed and high-resolution photography have been used to investigate the relationship between creation, expansion, and collapse of a vapor cavity induced by a 6 ns laser pulse and the subsequent nucleation of crystals. A thin layer of supersaturated aqueous solutions of (NH4)2SO4 and KMnO4 was confined between two glass plates with a separation of 50 and 100 μm. The expansion and collapse of the laser-induced vapor bubble occurred over a total time scale of 200 μs, while the first identifiable crystal appears one second after the laser pulse. Crystals were observed to form on a ring with a diameter of 70 μm centered in the focal point of the laser. The ring is preceded by an optical disturbance observed through the cavity around 30–50 μs after the laser pulse and vapor cavity formation. This ring-shaped optical disturbance originates from changes in refractive index induced by crystal nuclei formation. The formation of the nuclei most probably coincides with the formation of the bubble, when the rate of evaporation and the supersaturation are at their maxima. Apparently, it takes the nuclei around 30–50 μs to grow to a particle size with a visible optical disturbanc