984 resultados para 114-704


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The self-diffusion properties of pure CH4 and its binary mixture with CO2 within MY zeolite have been investigated by combining an experimental quasi-elastic neutron scattering (QENS) technique and classical Molecular dynamics simulations. The QENS measurements carried out at 200 K led to an unexpected self-diffusivity profile for Pure CH4 with the presence of a maximum for a loading of 32 CH4/unit cell, which was never observed before for the diffusion of apolar species in azeolite system With large windows. Molecular dynamics simulations were performed using two distinct microscopic models for representing the CH4/NaY interactions. Depending on the model, we are able to fairly reproduce either the magnitude or the profile of the self-diffusivity.Further analysis allowed LIS to provide some molecular insight into the diffusion mechanism in play. The QENS measurements report only a slight decrease of the self-diffusivity of CH4 in the presence of CO2 when the CO2 loading increases. Molecular dynamics simulations successfully capture this experimental trend and suggest a plausible microscopic diffusion mechanism in the case of this binary mixture.

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The mechanism by which outflows and plausible jets are driven from black hole systems still remains observationally elusive. This notwithstanding, several observational evidences and deeper theoretical insights reveal that accretion and outflow/jet are strongly correlated. We model an advective disk-outflow coupled dynamics, incorporating explicitly the vertical flux. Inter-connecting dynamics of outflow andaccretion essentially upholds the conservation laws. We investigate the properties of the disk-outflow surface and its strong dependence on the rotation parameter of the black hole. The energetics of the disk outflow strongly depend on the mass, accretion rate, and spin of the black holes. The model clearly shows that the outflow power extracted from the disk increases strongly with the spin of the black hole, inferring that the power of the observed astrophysical jets has a proportional correspondence with the spin of the central object. In the case of blazars (BL Lacs and flat spectrum radio quasars, FSRQs), most of their emission are believed to be originated from their jets. It is observed that BL Lacs are relatively low luminous than FSRQs. The luminosity might be linked to the power of the jet, which in turn reflects that the nuclear regions of the BL Lac objects have a relatively low spinning black hole compared to that in the case of FSRQs. If extreme gravity is the source that powers strong outflows and jets, then the spin of the black hole, perhaps, might be the fundamental parameter to account for the observed astrophysical processes in an accretion powered system.

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A class of conjugated molecules containing donor (thiophene) and acceptor (malononitrile) is synthesized by Knoevenagel condensation reaction between 2-(2,6-dimethy1-4H-pyran-4-ylidene) malononitrile and thiophene carbaldehyde containing two and three thiophene units. The resulting molecules are characterized by H-1 and C-13 NMR. We have performed UV-vis absorption, fluorescence, and cyclic voltammetry measurements on these materials. The spectroscopic and electrochemical measurements proved beyond doubt that these materials possess lowexcitation gap and are suitable for being an active material in various electronic devices. We have also performed electronic structure calculations using density functional theory (DFT) and INDO/SCI methods to characterize the ground and excited states of this class of molecules. These donor-acceptor molecules show a strong charge transfercharacter that increases with the increase in the number of thiophene rings coupled to the malononitrile acceptor moiety. We have also calculated the pi-coherence length, Stoke's shift, and effect of solvents on excited states for this class of molecules, Our theoretical values agree well with experimental results.

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We show that a model of target location involving n noninteracting particles moving subdiffusively along a line segment (a generalization of a model introduced by Sokolov et al. [Biophys. J. 2005, 89, 895.]) provides a basis for understanding recent experiments by Pelta et al. [Phys. Rev. Lett. 2007, 98, 228302.] on the kinetics of diffusion-limited gel degradation. These experiments find that the time t(c) taken by the enzyme thermolysin to completely hydrolyze a gel varies inversely as roughly the 3/2 power of the initial enzyme concentration [E]. In general, however, this time would be expected to vary either as [E](-1) or as [E](-2), depending on whether the Brownian diffusion of the enzyme to the site of cleavage took place along the network chains (1-d diffusion) or through the pore spaces (3-d diffusion). In our model, the unusual dependence of t(c) on [E] is explained in terms of a reaction-diffusion equation that is formulated in terms of fractional rather than ordinary time derivatives.

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In this paper we shall study a fractional order functional integral equation. In the first part of the paper, we proved the existence and uniqueness of mile and global solutions in a Banach space. In the second part of the paper, we used the analytic semigroups theory oflinear operators and the fixed point method to establish the existence, uniqueness and convergence of approximate solutions of the given problem in a separable Hilbert space. We also proved the existence and convergence of Faedo-Galerkin approximate solution to the given problem. Finally, we give an example.

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From Strangers to Peer Acquaintances Mothers and Fathers with a First Born and their Experiences of the New Family Training Process in Espoo This research is composed of two interrelated case studies. The first case was a family training experiment conducted in the City of Espoo during 2003 2005. In the experiment, the content, duration and procedures were modified from the previous family training policy. The new family training system stressed peer group activities and the peer support formed between the participating mothers and fathers. The second case comprised the stories of 14 parents about the family training process. The aim of the research was to find out whether peer group activities and support was demonstrated between the participating parents during the family training process. The second case and its narrative material constituted the main research material. The narrative material was collected by interviews. Eight mothers and six fathers were interviewed twice within a year between their sessions. The parents also filled in questionnaires about their daily life and participated in a drawing exercise, in which they visualized how they experienced the family training during the antenatal period, labour and the postnatal period. A narrative approach was applied to the analysis of the narrative material. The analysis consisted of several stages. In the final stage, the fathers main story was combined with all the participating fathers personal stories. The mothers main story was also constructed from their personal stories. The study implicated that in some parts the mothers and fathers main stories were similar. During the family training, previously unacquainted parents became peer acquaintances. In particular, the first born as a focus created interaction and cooperation among the parents. Parents in similar circumstances became significant to each other. Different figurations formed during the family training. However, the main stories did not always entwine. The mothers were in contact with the other mothers almost daily using mobile phones, email and mother-child activities. The fathers employed outside home met each other only during the family training meetings, but felt being supported by the other fathers. Some families visited one another outside of the family training. This new type of family training had characteristics typical of the project society. The parents peer activities were based on trust, negotiation and contracts between partners. The parents evaluated the benefits of participation in the family training. If they appreciated the activities with peers and peer compassion, they were willing to participate in the family training during the postnatal period. Keywords: family training, parenthood, motherhood, fatherhood, peer, peer group, peer support, social support, social relationships, figurations, the project society, pastoral power, epistolary power

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This doctoral thesis explores the development of drug markets and drug related crime in Finland since the mid 1990s, as well as public control measures aimed at solving problems related to drug crime. The research further examines the criminal career of persons having committed drug crime, as well as their socio-economic background. The period since the mid 1990s is, on the one hand, characterized by increasing use of drugs and increasingly severe drug problems. On the other hand, this period is also characterized by intensified drug control. Also criminality associated with drugs has increased and become more severe. During this period the prevention of drug problems became a focal issue for authorities, and resources were increased for activities geared towards fighting drugs. Along with this development, Finnish drug policy has been balancing between therapeutic activities and control. A focal point in this thesis is the question how society addresses drug problems, as well as how this differs from efforts to solve other problems. Why are criminal means so readily used when dealing with drug problems; why have the police received an extended mandate to use coercive force; and why has the field for imposing administrative sanctions been extended? How has the extension of drug control affected general thinking in criminal policy? The subject matter in this thesis is approached in a criminological and criminal policy perspective. The thesis is made up of four research articles and a Summary Article. In the Summary Article the studies were placed into the Finnish research context of drug criminality and drug control as well as criminal policy. Furthermore, the author has assessed his own research location as a drug control researcher. Applying the notion of risk, an analysis was made of threats posed by drugs to society. Theoretical perspectives were also brought to the fore on how society may regulate drug problems and threats associated with them. Based on research literature and administrative documents, an analysis was made of the relation between drug related social and health policy and criminal justice control. An account was also made of the development of drug control in Finland since the mid 1990s. There has been a strong increase in control by the criminal justice system since the mid 1990s. Penalties have been made more stringent, more efficient means have been developed to trace the financial gain from the offence, opportunities for money laundering have been prevented and the police has obtained ample new powers of inquiry. New administrative measures have been directed towards drug users, such as introducing drug tests in working life, checking the applicants criminal record for certain jobs, as well as the threat of losing one s driving licence in cases where a physician has established drug addiction. In the 1990s the prevention of drug crimes and their disclosure were made part of the police s control activities nationwide. This could clearly be seen in increased criminal statistics. There are humiliating elements associated with the police s drug control that should be eliminated for the benefit of everybody. Furthermore, the criminal control is directed towards persons in a weak socio-economic position. A drug verdict may set off a marginalization process that may be very difficult to halt. Drug control is selective and generates repressive practises. The special status accorded drug problems is also revealed in the way in which the treatment of drug addicts has developed.

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We present three measurements of the top-quark mass in the lepton plus jets channel with approximately 1.9 fb-1 of integrated luminosity collected with the CDF II detector using quantities with minimal dependence on the jet energy scale. One measurement exploits the transverse decay length of b-tagged jets to determine a top-quark mass of 166.9+9.5-8.5 (stat) +/- 2.9 (syst) GeV/c2, and another the transverse momentum of electrons and muons from W-boson decays to determine a top-quark mass of 173.5+8.8-8.9 (stat) +/- 3.8 (syst) GeV/c2. These quantities are combined in a third, simultaneous mass measurement to determine a top-quark mass of 170.7 +/- 6.3 (stat) +/- 2.6 (syst) GeV/c2.

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We report on a CDF measurement of the total cross section and rapidity distribution, $d\sigma/dy$, for $q\bar{q}\to \gamma^{*}/Z\to e^{+}e^{-}$ events in the $Z$ boson mass region ($66M_{ee}

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We present the results of a search for Higgs bosons predicted in two-Higgs-doublet models, in the case where the Higgs bosons decay to tau lepton pairs, using 1.8 inverse fb of integrated luminosity of proton-antiproton collisions recorded by the CDF II experiment at the Fermilab Tevatron. Studying the observed mass distribution in events where one or both tau leptons decay leptonically, no evidence for a Higgs boson signal is observed. The result is used to infer exclusion limits in the two-dimensional parameter space of tan beta versus m(A).

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We have measured the differential cross section for the inclusive production of psi(2S) mesons decaying to mu^{+} mu^{-1} that were produced in prompt or B-decay processes from ppbar collisions at 1.96 TeV. These measurements have been made using a data set from an integrated luminosity of 1.1 fb^{-1} collected by the CDF II detector at Fermilab. For events with transverse momentum p_{T} (psi(2S)) > 2 GeV/c and rapidity |y(psi(2S))| psi(2S)X) Br(psi(2S) -> mu^{+} mu^{-}) to be 3.29 +- 0.04(stat.) +- 0.32(syst.) nb.

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We have observed the reactions p+pbar --> p+X+pbar, with X being a centrally produced J/psi, psi(2S) or chi_c0, and gamma+gamma --> mu+mu-, in proton- antiproton collisions at sqrt{s} = 1.96 TeV using the Run II Collider Detector at Fermilab. The event signature requires two oppositely charged muons, each with pseudorapidity |eta| mu+mu-. Events with a J/psi and an associated photon candidate are consistent with exclusive chi_c0 production through double pomeron exchange. The exclusive vector meson production is as expected for elastic photo- production, gamma+p --> J/psi(psi(2S)) + p, which is observed here for the first time in hadron-hadron collisions. The cross sections ds/dy(y=0) for p + pbar --> p + X + pbar with X = J/psi, psi(2S) orchi_c0 are 3.92+/-0.62 nb, 0.53+/-0.14 nb, and 75+/-14 nb respectively. The cross section for the continuum, with |eta(mu+/-)|

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We present the results of a search for Higgs bosons predicted in two-Higgs-doublet models, in the case where the Higgs bosons decay to tau lepton pairs, using 1.8 inverse fb of integrated luminosity of proton-antiproton collisions recorded by the CDF II experiment at the Fermilab Tevatron. Studying the observed mass distribution in events where one or both tau leptons decay leptonically, no evidence for a Higgs boson signal is observed. The result is used to infer exclusion limits in the two-dimensional parameter space of tan beta versus m(A).

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A search for a narrow diphoton mass resonance is presented based on data from 3.0 fb^{-1} of integrated luminosity from p-bar p collisions at sqrt{s} = 1.96 TeV collected by the CDF experiment. No evidence of a resonance in the diphoton mass spectrum is observed, and upper limits are set on the cross section times branching fraction of the resonant state as a function of Higgs boson mass. The resulting limits exclude Higgs bosons with masses below 106 GeV at a 95% Bayesian credibility level (C.L.) for one fermiophobic benchmark model.