2,669 research outputs found

    Simultaneously optimizing the interdependent thermoelectric parameters in Ce(Ni1x_{1-x}Cux_x)2_2Al3_3

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    Substitution of Cu for Ni in the Kondo lattice system CeNi2_2Al3_3 results in a simultaneous optimization of the three interdependent thermoelectric parameters: thermoelectric power, electrical and thermal conductivities, where the electronic change in conduction band induced by the extra electron of Cu is shown to be crucial. The obtained thermoelectric figure of merit zTzT amounts to 0.125 at around 100 K, comparable to the best values known for Kondo compounds. The realization of ideal thermoelectric optimization in Ce(Ni1x_{1-x}Cux_x)2_2Al3_3 indicates that proper electronic tuning of Kondo compounds is a promising approach to efficient thermoelectric materials for cryogenic application.Comment: 4 pages, 4 figures. Accepted for publication in Physical Review

    Predictions of super-exotic heavy mesons from KBBK^{*}B^{*}B^{*} interactions

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    We make a theoretical study of the three-body system composed of KˉBˉBˉ{\bar K^*}{\bar B^*}{\bar B^*} to look for possible bound states, which could be associated to mesonic resonances of very exotic nature, containing open strange and double-bottom flavours. The three-body interaction is evaluated by using the fixed center approach to the Faddeev equations where the BˉBˉ{\bar B^*}{\bar B^*} is bound forming an I(JP)=0(1+)I(J^P)=0(1^+) state, as it was found in previous works, and the third particle, the Bˉ{\bar B^*}, of much smaller mass, interacts with the components of the cluster. We obtain bound states for all the channels considered: spin J=0J=0, 1 and 2, all of them with isospin I=1/2I=1/2 and negative parity.Comment: 9 pages, 5 figure

    Molecular states of DDKˉ D^* D^* \bar{K}^* nature

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    We study the interaction of two D D^* and a Kˉ\bar{K}^{*} by using the Fixed Center Approximation to the Faddeev equations to search for bound states of the three body system. Since the DD D^* D^* interaction is attractive and gives a bound state, and so is the case of the DKˉD^* \bar{K}^{*} interaction, where the JP=0+J^{P}=0^{+} bound state is identified with the X0(2900)X_0 (2900), the DDKˉ D^* D^* \bar{K}^{*} system leads to manifestly exotic bound states with ccsccs open quarks. We obtain bound states of isospin I=1/2I=1/2, negative parity and total spin J=0,1,2J=0,1,2. For J=0J=0 we obtain one state, and for J=1,2J=1,2 we obtain two states in each case. The binding energies range from 5656 MeV to 151151 MeV and the widths from 8080 MeV to 100100 MeV.Comment: 19 pages, 7 figures, 1 table, version published in Phys Rev

    Role of f0(980)f_0(980) and a0(980)a_0(980) in the BπK+KB^- \to \pi ^- K^+ K^- and BπK0Kˉ0B^- \to \pi ^- K^0 \bar K^0 reactions

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    In this work we study the role of the f0(980)f_0(980) and a0(980)a_0(980) resonances in the low K+K K ^{+} K^{-} and K0Kˉ0K^0 \bar K^0 invariant-mass region of the BπK+KB^- \to \pi ^- K^+ K^- and BπK0Kˉ0B^- \to \pi ^- K^0 \bar K^0 reactions. The amplitudes are calculated by using the chiral unitary SU(3)\rm SU(3) formalism, in which these two resonances are dynamically generated from the unitary pseudocalar-pseudoscalar coupled-channel approach. The amplitudes are then used as input in the evaluation of the mass distributions with respect to the K+K K^{+}K^{-} and K0Kˉ0 K^{0}\bar K^{0} invariant-masses, where the contributions coming from the I=0I=0 and I=1I=1 components are explicitly assessed. Furthermore, the contribution of the K(892)0K K^{\ast }(892)^0 K^- production and its influence on the πK+ \pi^{-} K^+ and K+K K^{+} K^- systems are also evaluated, showing that there is no significant strength for small K+K K^{+} K^- invariant mass. Lastly, the final distributions of Minv2(K±K) M_{\rm inv}^2( K^{\pm}K^{\mp} ) for the BπK±KB^{\mp} \to \pi ^{\mp} K^{\pm}K^{\mp} reactions are estimated and compared with the LHCb data. Our results indicate that the I=0I=0 component tied to the f0(980)f_0(980) excitation generates the dominant contribution in the range of low K+K K ^{+} K^{-} invariant-mass.Comment: 11 pages, 10 figure

    Manipulating transgenes using a chromosome vector

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    Recent technological advances have enabled us to visualize the organization and dynamics of local chromatin structures; however, the comprehensive mechanisms by which chromatin organization modulates gene regulation are poorly understood. We designed a human artificial chromosome vector that allowed manipulation of transgenes using a method for delivering chromatin architectures into different cell lines from human to fish. This methodology enabled analysis of de novo construction, epigenetic maintenance and changes in the chromatin architecture of specific genes. Expressive and repressive architectures of human STAT3 were established from naked DNA in mouse embryonic stem cells and CHO cells, respectively. Delivery of STAT3 within repressive architecture to embryonic stem cells resulted in STAT3 activation, accompanied by changes in DNA methylation. This technology for manipulating a single gene with a specific chromatin architecture could be utilized in applied biology, including stem cell science and regeneration medicine

    Pionic Atom Spectroscopy in the (d,3He) reaction at finite angles

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    We study the formation of deeply bound pionic atoms in the (d,3He) reactions theoretically and show the energy spectra of the emitted 3He at finite angles, which are expected to be observed experimentally. We find that the different combinations of the pion-bound and neutron-hole states dominate the spectra at different scattering angles because of the matching condition of the reaction. We conclude that the observation of the (d,3He) reaction at finite angles will provide the systematic information of the pionic bound states in each nucleus and will help to develop the study of the pion properties and the partial restoration of chiral symmetry in nuclei.Comment: 7 pages, 4 figures, 1 tabl

    Kummiluokkatoiminnan arviointi

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    Tämän opinnäytetyön tarkoituksena oli kuvata ja arvioida kummiluokkatoimintaa ja sen vaikutuksia sairaanhoitajaopiskelijan/terveydenhoitajaopiskelijan opintoihin sekä työelämään pääsemiseen ja sopeutumiseen. Tämä opinnäytetyö toteutettiin empiirisenä tutkimuksena. Kummiluokkatoimintaa arvioitiin kyselyn avulla. Kysely tehtiin sähköisenä Webropol-kyselynä. Kysely lähetettiin sähköpostitse 55 hoitoalan opiskelijalle, jotka olivat olleet mukana kummiluokkatoiminnassa. Kyselyyn vastasi yhdeksän opiskelijaa, vastausprosentti oli 16,36 %. Kysely sisälsi sekä avoimia kysymyksiä että monivalintakysymyksiä. Vastausten analysointiin käytettiin sisällönanalyysiä sekä tilastointia. Kyselyn tulokseksi saatiin, että opiskelijat eivät pääosin olleet tyytyväisiä kummiluokkatoimintaan sellaisena kuin se oli toteutunut. Kummiluokkatapaamisia oli ollut liian vähän, eikä niillä ollut vaikutusta työn saantiin. Kuitenkin se toiminta, mitä opiskelijoille oli tarjottu, oli mieleistä. Muutaman opiskelijan mielestä toiminta oli lisännyt halua työskennellä Varsinais-Suomen sairaanhoitopiirissä ja yhden mielestä se oli tehnyt työnhausta helpompaa. Myös vierailukäynnit ja esitykset olivat olleet kiinnostavia, niitä olisi vain pitänyt olla enemmän. Tämän opinnäytetyön tuomaa tietoa voidaan käyttää kummiluokkatoiminnan kehittämiseen, jotta hoitoalan opiskelijat saadaan yhä enemmän sitoutumaan ja kiinnostumaan tulevasta ammatistaan. Saadut tulokset antavat myös lisää syitä kummiluokkatoiminnan jatkamiselle. Jatkotutkimuksina voisi selvittää, miten kummiluokkatoiminta vaikuttaa Turun Yliopistolliseen sairaalaan ja VSSHP:in, eli hyötyykö toiminnasta opiskelijoiden lisäksi myös organisaatio.The purpose of this study was to describe and evaluate the godparent activities and its effects on nursing studies, as well as to work to reach and adjust. This thesis has been implemented by empirical research. Godparent activity was assessed using an inquiry. The inquiry was conducted by Webropol survey. The inquiry was sent by e-mail of 55 nursing students, who had been involved in godparent activities. Nine students responded to the inquiry, the response rate was 16.36%. The inquiry contained both open questions and multiple choice questions. Content analysis and statistics were used for the analysis of the responses. The inquiry led to the result that students are not generally been satisfied with the godparent activities as it had been. Godparent meetings were only few, nor did they have the effect of employment. However, it is low, what activities were offered to students was worthwhile. A few view, the activities had added desire to work in Hospital District of Southwest Finland, and one thought it was done work search easier. Also, visits and information lectures were interesting; they would only have been more. This thesis can be used to develop the godparent activities, to get nursing students to increasingly commit to and interested in their future profession. The information obtained will also provide more reasons to continuation of godparent activities. Possible further studies could figure out how godparent activities affect the Turku University Hospital and in Hospital District of Southwest Finland, to benefit for the students, but also the organization

    Multiplet ligand-field theory using Wannier orbitals

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    We demonstrate how ab initio cluster calculations including the full Coulomb vertex can be done in the basis of the localized, generalized Wannier orbitals which describe the low-energy density functional (LDA) band structure of the infinite crystal, e.g. the transition metal 3d and oxygen 2p orbitals. The spatial extend of our 3d Wannier orbitals (orthonormalized Nth order muffin-tin orbitals) is close to that found for atomic Hartree-Fock orbitals. We define Ligand orbitals as those linear combinations of the O 2p Wannier orbitals which couple to the 3d orbitals for the chosen cluster. The use of ligand orbitals allows for a minimal Hilbert space in multiplet ligand-field theory calculations, thus reducing the computational costs substantially. The result is a fast and simple ab initio theory, which can provide useful information about local properties of correlated insulators. We compare results for NiO, MnO and SrTiO3 with x-ray absorption, inelastic x-ray scattering, and photoemission experiments. The multiplet ligand field theory parameters found by our ab initio method agree within ~10% to known experimental values
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