The teaching profession in Europe : historical and sociological analysis

A possible effect of direct CP violation in D -> K-S(0)pi(+)pi(-) decay on the gamma measurement from B-+/- -> DK +/-, D -> K-S(0)pi(+)pi(-) Dalitz plot analysis is considered. Systematic uncertainty of gamma coming from the current limits on direct CP violation in D -> K-S(0)pi(+)pi(-) is estimated, and a modified model-independent procedure of B-+/- -> DK +/-, D -> K-S(0)pi(+)pi(-) Dalitz plot analysis is proposed that gives an unbiased gamma measurement even in presence of direct CP violation in charm decays. The technique is applicable to other threebody D decays such as D-0 -> (KSK+K-)-K-0, D-0 -> pi(+)pi(-)pi(0), etc

Biomechanical Similarities And Differences Of A. Agassi's First And Second Serves

The purpose of this study was to perform three-dimensional analysis of the instrumentally recorded elements of Andre Agassi's serving technique during competition. A video based analysis system was used to analyze the data provided by two sVHS (60 Hz) back and right side view camcorders. Four successful first and second serves into the deuce court were selected for the analysis. Spatial kinematic characteristics of the defined points and segments were analyzed. The average speed of the ball for the first serve was 45.8±2.2 m/s and angled close to the sideline. The second serve was hit with pronounced topspin and achieved a ball speed of 37.9±2.4 m/s. Kinematic characteristics of the CG in the preparation phase reflects direction, velocity and rotation of the ball. The first serve's CG maximum speed was 1.89±0.10 m/s. Angle ofthe horizontal velocity at the moment of impact was 17±4 degrees. The characteristics of the second serve were 1.71±0.09 m/sand 1l±5 degrees. However, the vertical component of CG velocity of the second serve was 12% higher than the first which most likely provided additional ball rotation. The ball positioning relative to the CG at the moment of impact for the first serve was 0.13±0.02 m forward and 0.12±0.04 m laterally. The second serve had no significant forward shift between the ball and CG. Lateral shift was 0.36±0.04 m. The impact height was relatively the same. Analysis of body segment movements during the first serve gives the following results: high speed right knee extension, hip and shoulder rotation provides pronounced forward body motion. In the second serve extension of the left knee was dominant with less influence by the hip and shoulder rotation, but with more notable lateral trunk action. No significant differences were found between right arm and racquet's relative movements during the first and the second serves. In both cases maximum angular velocities of the elbow extension and a racquet swing were 1185±110 deg/s and 3240±180 deg/sec respectively with the same structure of the velocity changes. It was found that in order to increase consistency of the second serve, Agassi while keeping the relative motion of his arm consistent from serve to serve, makes changes in his vertical and lateral position, and the forward motion of his body which causes changes in the velocity and rotation of the ball. Since the torso and leg muscles are larger than the arm muscles, they are stronger and more stable, thus providing consistency in changes of motion patterns for the second serve

Development of hollow electron beams for proton and ion collimation

Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.Comment: 3 pp. 1st International Particle Accelerator Conference: IPAC'10, 23-28 May 2010: Kyoto, Japa

Poisson Structures on Trivial Extension Algebras

We present a class of Poisson structures on trivial extension algebras which generalize some known structures induced by Poisson modules. We show that there exists a one-to-one correspondence between such a class of Poisson structures and some data involving (not necessarily flat) contravariant derivatives, and then we give a formulation of this result in terms of Lie algebroids. Some properties of the first Poisson cohomology are also presented. Examples coming from Poisson modules and Poisson submanifolds are given.Comment: 31 page

Потребление микропластика рыбами с различным пищевым поведением в реках Обь и Енисей

Microplastic particles in the size range 0.15 to 5.00 mm were quantified and characterised in the gastrointestinal tracts of three wild freshwater fish (n = 141) from the Ob and Yenisei rivers, including common ruffe (Gymnocephalus cernua L.), Siberian dace (Leuciscus baicalensis Dybowski) and European perch (Perca fluviatilis L.). Microplastics were found in the gastrointestinal tract of 62% of the fish examined, ranging from 18.5% in the Yenisei perch sample to 92.6% in the Ob ruffe sample. The vast majority of microplastics in all fish species were fibres (up to 99.7% of all particles detected in perch), followed by irregularly shaped fragments (up to 22.7% in ruffe), with no preference between the three species. Spheres and films were found exclusively in dace and ruffe, with proportions of 3.7% and 1.2% respectively. Particles consisted of polyethylene terephthalate, polypropylene, polyamide and other synthetic polymers with a significant proportion of highly degraded polymers. The mean MP content in fish GITs ranged from 0.44 ± 0.25 items per individual in Yenisei perch to 3.81 ± 0.55 items per individual in Ob ruffe. Particle burdens in fish were significantly higher in the Ob than in the Yenisei (p dace (omnivorous) > perch (hunter) in both rivers (p < 0.01). This study was the first to quantify MP consumption by freshwater fish of different species in the Ob and Yenisei rivers and to identify patterns associated with different feeding habits

Evidence for microplastics contamination of the remote tributary of the Yenisei River, Siberia - The pilot study results

This study is a pioneering attempt to count microplastics (MPs) in the Yenisei River system to clarify the role of Siberian Rivers in the transport of MPs to the Arctic Ocean. The average MPs content in the surface water of the Yenisei large tributary, the Nizhnyaya Tunguska River, varied from 1.20 ± 0.70 to 4.53 ± 2.04 items/m3, tending to increase along the watercourse (p < 0.05). Concentrations of MPs in bottom sediments of the two rivers were 235 ± 83.0 to 543 ± 94.1 with no tendency of downstream increasing. Linear association (r = 0.952) between average organic matter content and average counts of MPs in bottom sediments occurred. Presumably MPs originated from the daily activities of the in-situ population. Further spatial-temporal studies are needed to estimate the riverine MPs fluxes into the Eurasian Arctic seas

Mathematical modeling of extraction process for biporous medium and analyze of pressure in particles and extraparticle space

Обґрунтовано математичну модель процесу відтиску матеріалів рослинного походження у одновимірній постановці. Середовище, що піддається відтиску, представляється у вигляді біпористої системи, системою міжчастинкових та внутрішньочастинкових просторів. Сформульовано рівняння фільтрації-консолідації з відповідними початковими та крайовими умовами як для міжчастинкового, так і внутрішньочастинкового просторів у припущенні, що для матеріалів рослинного походження, міжчастинковий шар пор володіє малою місткістю, а пори в частинках – високою. Проведено числове моделювання профілів тисків в мікро- та макро порах біпористого середовища для двох матеріалів з різними степенями попередньої деформованості внутрішньої структури. Отримані результати вказують на відтермінування падіння значення тиску в частинці та уповільнення процесу консолідації для менш деформованого середовища.During solid-liquid expression, the porous layer formed by a whole fruit or fragmentized material is subjected to unidirectional or complex compression in industrial presses. Such compression can be carried out under constant or variable parameters (pressure, deformation rate). Physical model of solid-liquid expression from liquid containing materials is presented in one-dimensional formulation. The layer of sliced cellular material is conceptualized as a double porosity system with extraparticle and intraparticle networks for liquid flowing. The liquid flowing occurs inside the particles (intraparticle space), outside the particles (extraparticle space) and between these two spaces. The sliced particles are rectangular parallelepipeds separated by the porous network. The extraparticles network forms the first porosity with low storage capacity and high hydraulic permeability. The sliced liquid containing particles form a second porosity with high storage capacity and low hydraulic permeability. The filtration-consolidation equations with corresponding initial and boundary conditions were formulated for both extraparticle and intraparticle networks. The extraparticle network was supposed to form the first porosity level, while the intraparticle network forms a second porosity. Using obtained numerical solutions, the liquid pressure distributions inside of porous particles and in the extraparticle space were calculated. The pressure distribution curves are presented in function of time and dimensionless geometrical coordinates. Computational modeling of pressure profiles in macro- and micropores versus time for different layer sections was done for plant material with two different compressibility-permeability characteristics corresponding different degrees of tissue destroying. Results show the delayed pressure drop in the intraparticle network and retardation of consolidation kinetics for the less destroyed plant tissue due to the lower value of consolidation coefficient. Therefore, the degree of destroying of cellular tissue can influence importantly on the pressure profiles and retardation of pressure drops inside the porous particles

An evaporation-based model of thermal neutron induced ternary fission of plutonium

Ternary fission probabilities for thermal neutron induced fission of plutonium are analyzed within the framework of an evaporation-based model where the complexity of time-varying potentials, associated with the neck collapse, are included in a simplistic fashion. If the nuclear temperature at scission and the fission-neck-collapse time are assumed to be ~1.2 MeV and ~10^-22 s, respectively, then calculated relative probabilities of ternary-fission light-charged-particle emission follow the trends seen in the experimental data. The ability of this model to reproduce ternary fission probabilities spanning seven orders of magnitude for a wide range of light-particle charges and masses implies that ternary fission is caused by the coupling of an evaporation-like process with the rapid re-arrangement of the nuclear fluid following scission.Comment: 25 pages, 12 figures, accepted for publication in IJMP