6,732 research outputs found

    Influence of Hydrodynamic Interactions on the Kinetics of Colloidal Particle's Adsorption

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    The kinetics of irreversible adsorption of spherical particles onto a flat surface is theoretically studied. Previous models, in which hydrodynamic interactions were disregarded, predicted a power-law behavior t2/3t^{-2/3} for the time dependence of the coverage of the surface near saturation. Experiments, however, are in agreement with a power-law behavior of the form t1/2t^{-1/2}. We outline that, when hydrodynamic interactions are considered, the assymptotic behavior is found to be compatible with the experimental results in a wide region near saturation.Comment: 4 pages, 1 figures, Phys. Rev. Lett. (in press

    Notifications Efficiency, Impact, and Interference in Second-Screen Scenarios

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    The growing use of second-screen devices stresses the importance of finding a balance between engagement, distraction, and disturbance of its users, while simultaneously watching television. In this framework, this article reports on a study designed to analyze the efficiency, impact, and interference of different notification strategies aiming to identify the best approach to be used when an alert is needed in second-screen scenarios. A prototype able to deliver synchronized information related with TV content, with intervals of 10, 30 and 60 s, followed by individual or combined notifications (e.g., audio, visual, and haptic—on the tablet and visual—on the TV) was developed. A laboratory adapted to replicate a living room was set up and a test that involved watching three segments of a 20-min clip while using the prototype was carried with 30 participants, under a cognitive walk-through protocol. Quantitative and qualitative results show that receiving notifications while watching TV is effective in alerting users about new information, despite its inherent cognitive disturbance for the TV viewing experience. It was also possible to highlight that in an HCI perspective, the most suitable strategy for integrating notifications (considering type and cadence) should be based on a combination of a visual notification (displayed only on the TV screen) along with a haptic notification (vibration on the tablet); spaced by an interval of at least 30 s

    KATANA - a charge-sensitive triggering system for the Sπ\piRIT experiment

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    KATANA - the Krakow Array for Triggering with Amplitude discrimiNAtion - has been built and used as a trigger and veto detector for the Sπ\piRIT TPC at RIKEN. Its construction allows operating in magnetic field and providing fast response for ionizing particles, giving the approximate forward multiplicity and charge information. Depending on this information, trigger and veto signals are generated. The article presents performance of the detector and details of its construction. A simple phenomenological parametrization of the number of emitted scintillation photons in plastic scintillator is proposed. The effect of the light output deterioration in the plastic scintillator due to the in-beam irradiation is discussed.Comment: 14 pages, 11 figure

    Ocena poziomu wiedzy osób dorosłych na temat resuscytacji krążeniowo : oddechowej (RKO) i użycia automatycznego defibrylatora zewnętrznego (AED) w miejscach publicznych

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    Wstęp. Wraz z rozwojem cywilizacji, wzrastającym tempem życia, rośnie liczba wypadków i chorób, zwłaszcza chorób układu krążenia. W Polsce średnia liczba zgonów około wypadkowych jest trzy razy wyższa niż średnia europejska. Wiedza na temat pierwszej pomocy jest bardzo ważna wśród społeczeństwa, które stanowi mocny filar niesienia pierwszej pomocy poszkodowanym w nagłych sytuacjach, które są stanami zagrożenia zdrowia i życia. Cel pracy. Celem pracy była ocena i porównanie wiedzy mieszkańców Kielc i Krakowa z zakresu pierwszej pomocy oraz obsługi i zastosowania Automatycznego Defibrylatora Zewnętrznego (AED). Materiał i metody. Grupę badawczą stanowiło 160 osób, z czego 80 osób było z Krakowa, w tym 45 kobiet i 35 mężczyzn i 80 osób z Kielc, w tym 45 kobiet i 35 mężczyzn. Wszyscy re-spondenci byli pełnoletni. W badaniach posłużono się metodą sondażu diagnostycznego bezpośredniego, losowego wykorzys-tując do tego celu narzędzie badawcze w postaci anonimowego kwestionariusza ankiety, opracowanego na bazie Wytycznych Resuscytacji Krążeniowo- Oddechowej 2005 (RKO). Wyniki. Mieszkańcy Krakowa wykazują lepszy poziom wiedzy, aczkolwiek znajomość i obsługa . Respondenci z Krakowa częściej i chętniej uczestniczą w szkoleniach z zakresu BLS-AED i pierwszej pomocy niż respondencki z Kielc. Wnioski. Poziom wiedzy z zakresu udzielania pierwszej pomocy, a przede wszystkim w zakresie resuscytacji krążeniowo - oddechowej i użycia AED przez społeczeństwo z Krakowa i Kielc jest niezadawalający. Istnieje pilna potrzeba wprowadzenia komplementarnego systemu nauczania zagadnień pierwszej pomocy opartego na międzynarodowych standardach, który zagwarantuje odpowiednią jakość edukacji oraz kształtowanie pozytywnych postaw niesienia pomocy, począwszy od wczesnego etapu edukacji szkolnej.Introduction: The number of accidents and diseases, especially cardio-vascular, is increasing along with the develop-ment of civilization and a growing pace of life. In Poland, the average number of accident fatalities is three times higher than the European average. The knowledge of first aid is very im-portant for society, which is a strong pillar of first aid to victims in emergency situations that are dangerous to health and life. The aim of the study: The aim of the study was to assess the knowledge of CPR and first aid in the event of sudden respiratory arrest and cardiac arrest (SCA) and the operation and use of the Automated External Defibrillator (AED). Material and methods: The study group consisted of 160 people, among whom 80 were from Kraków, including 45 women and 35 men and 80 people were from Kielce, including 45 women and 35 men. All the respondents were adults. The method of diagnostic survey was applied in the study. The research instrument was an anonymous survey questionnaire created on the basis of the Car-dio-Pulmonary Resuscitation Guidelines 2005 (CPR). Results: Residents of Kraków have better knowledge of first aid, however the knowledge and operation of the AED among both residents of Kraków and Kielce is inadequate. Respondents from Kraków more often and more willingly participate in BLS-AED and first aid training than respondents from Kielce. Conclusions: The level of knowledge of first aid and especially of Cardio-Pulmonary Resuscitation and the application of the AED is unsatisfactory among residents of Kraków and Kielce. There is an urgent need for a complementary system of first aid instruction which would be based on international standards, and which would ensure an appropriate quality of education and develop a proper attitude among people, starting with the earliest stage of school education

    Asymmetries in random motions of neutral Hydrogen gas in spiral galaxies

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    (Abridged). It has been recently shown that random motions of the neutral Hydrogen gas of the Triangulum galaxy (M33) exhibit a bisymmetric perturbation which is aligned with the minor axis of the galaxy, suggesting a projection effect. To investigate if perturbations in the velocity dispersion of nearby discs are comparable to those of M33, the sample is extended to 32 galaxies from The HI Nearby Galaxy Survey and the Westerbork HI Survey of Spiral and Irregular Galaxies. We study velocity asymmetries in the disc planes by performing Fourier transforms of high-resolution HI velocity dispersion maps corrected for beam smearing effects, and measure the amplitudes and phase angles of the Fourier harmonics. We find strong perturbations of first, second and fourth orders. The strongest asymmetry is the bisymmetry, which is predominantly associated with the presence of spiral arms. The first order asymmetry is generally oriented close to the disc major axis, and the second and fourth order asymmetries are preferentially oriented along intermediate directions between the major and minor axes of the discs. These results are evidence that strong projection effects shape the HI velocity dispersion maps. The most likely source of systematic orientations is the anisotropy of velocities, through the projection of streaming motions stronger along one of the planar directions in the discs. Moreover, systematic phase angles of asymmetries in the HI velocity dispersion could arise from tilted velocity ellipsoids. We expect a larger incidence of correlation between the radial and tangential velocities of HI gas. Our methodology is a powerful tool to constrain the dominant direction of streaming motions and thus the shape of the velocity ellipsoid of HI gas, which is de facto anisotropic at the angular scales probed by the observations.Comment: 40 pages, 33 figures. Accepted for publication in Astronomy & Astrophysics. Full resolution version available upon reques

    Transmission Distortion of MCT1 rs1049434 among Polish Elite Athletes

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    Background: To date, nearly 300 genetic markers were linked to endurance and power/strength traits. The current study aimed to compare genotype distributions and allele frequencies of the common polymorphisms: MCT1 rs1049434, NRF2 rs12594956, MYBPC3 rs1052373 and HFE rs1799945 in Polish elite athletes versus nonathletes. Methods: The study involved 101 male elite Polish athletes and 41 healthy individuals from the Polish population as a control group. SNP data were extracted from whole-genome sequencing (WGS) performed using the following parameters: paired reads of 150 bps, at least 90 Gb of data per sample with 300 M reads and 30x mean coverage. Results: All the analyzed polymorphisms conformed to Hardy-Weinberg equilibrium (HWE) in athletes and the control group, except the MCT1 rs1049434, where allele T was over-represented in the elite trainers' group. No significant between-group differences were found for analyzed polymorphisms. Conclusions: The MCT1 rs1049434 transmission distortion might be characteristic of Polish athletes and the effect of strict inclusion criteria. This result and the lack of statistically significant changes in the frequency of other polymorphisms between the groups might result from the small group size

    Tailoring the FeO/SiO2 ratio in electric arc furnace slags to minimize the leaching of vanadium and chromium

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    Based on recently published research on leaching control mechanisms in electric arc furnace (EAF) slags, it is assumed that a FeO/SiO2 ratio of around one leads to low leached V and Cr concentrations. This ratio influences the mineral phase composition of the slag toward higher amounts of spinel and a lower solubility of calcium silicate phases by suppressing the formation of magnesiowuestite and highly soluble calcium silicate phases. To evaluate this hypothesis, laboratory and scaled up tests in an EAF pilot plant were performed on slag samples characterized by elevated V and Cr leaching and a high FeO/SiO2 ratio. Prior to the melting experiments, the optimum FeO/SiO2 ratio was calculated via FactSageTM. In the melting experiments, the ratio was adjusted by adding quartz sand, which also decreased the basicity (CaO/SiO2) of the slag. As a reference, remelting experiments without quartz sand addition were conducted and additionally, the influence of the cooling rate of the slag was examined. The remelted (without quartz sand) and the remelted modified slags (with quartz sand) were analyzed chemically and mineralogically and the leaching behavior was investigated. The modification of the slags yielded a minimized release of V and Cr, supporting the hypothesis that the FeO/SiO2 ratio influences the mineralogy and the leaching behavior

    The ASY-EOS experiment at GSI: investigating the symmetry energy at supra-saturation densities

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    The elliptic-flow ratio of neutrons with respect to protons in reactions of neutron rich heavy-ions systems at intermediate energies has been proposed as an observable sensitive to the strength of the symmetry term in the nuclear Equation Of State (EOS) at supra-saturation densities. The recent results obtained from the existing FOPI/LAND data for 197^{197}Au+197^{197}Au collisions at 400 MeV/nucleon in comparison with the UrQMD model allowed a first estimate of the symmetry term of the EOS but suffer from a considerable statistical uncertainty. In order to obtain an improved data set for Au+Au collisions and to extend the study to other systems, a new experiment was carried out at the GSI laboratory by the ASY-EOS collaboration in May 2011.Comment: Talk given by P. Russotto at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS
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