649 research outputs found
Second-order electronic correlation effects in a one-dimensional metal
The Pariser-Parr-Pople (PPP) model of a single-band one-dimensional (1D)
metal is studied at the Hartree-Fock level, and by using the second-order
perturbation theory of the electronic correlation. The PPP model provides an
extension of the Hubbard model by properly accounting for the long-range
character of the electron-electron repulsion. Both finite and infinite version
of the 1D-metal model are considered within the PPP and Hubbard approximations.
Calculated are the second-order electronic-correlation corrections to the total
energy, and to the electronic-energy bands. Our results for the PPP model of 1D
metal show qualitative similarity to the coupled-cluster results for the 3D
electron-gas model. The picture of the 1D-metal model that emerges from the
present study provides a support for the hypothesis that the normal metallic
state of the 1D metal is different from the ground state.Comment: 21 pages, 16 figures; v2: small correction in title, added 3
references, extended and reformulated a few paragraphs (detailed information
at the end of .tex file); added color to figure
Atomic and electronic structure of graphene oxide/Cu interface
The results of X-ray photoemission (XPS) and valence bands spectroscopy,
optically stimulated electron emission (OSEE) measurements and density
functional theory based modeling of graphene oxide (GO) placed on Cu via an
electrophoretic deposition (EPD) are reported. The comparison of XPS spectra of
EPD prepared GO/Cu composites with those of as prepared GO, strongly reduced
GO, pure and oxidized copper demonstrate the partial (until C/O ratio about
two) removal of oxygen-containing functional groups from GO simultaneously with
the formation of copper oxide-like layers over the metallic substrate. OSEE
measurements evidence the presence of copper oxide phase in the systems
simultaneously with the absence of contributions from GO with corresponding
energy gap. All measurements demonstrate the similarity of the results for
different thickness of GO cover of the copper surface. Theoretical modeling
demonstrates favorability of migration of oxygen-containing functional groups
from GO to the copper substrate only for the case of C/O ratio below two and
formation of Cu-O-C bonds between substrate and GO simultaneously with the
vanishing of the energy gap in GO layer. Basing on results of experimental
measurements and theoretical calculations we suggest the model of atomic
structure for Cu/GO interface as Cu/CuO/GO with C/O ratio in gapless GO about
two.Comment: 22 pages, 14 figures, accepted to Thin Solid Films journa
Analiza przyczyn i rodzaju wtórnych zabiegów interwencyjnych po całkowitej korekcji zespołu Fallota u dzieci. Obserwacje wczesne i średnioodległe
Cel pracy: Analiza przyczyn, rodzaju i częstości oraz wyników zabiegów reinterwencyjnych po całkowitej korekcji zespołu Fallota (TOF) w obserwacji średniookresowej.
Materiał i metody: Badana grupa obejmowała 230 dzieci (137 M, 93 Ż) z TOF, poddanych całkowitej korekcji w wieku 2-202 miesięcy (śr. 53,5 ± 41,4), w tym 62 w wieku do 24 miesięcy, 93 w przedziale 25-60 miesięcy życia i 75 starszych, które leczono w okresie 01.01.1990-31.12.2000 r. Z grupy tej zmarło ogółem 10 dzieci (4,3%), głównie we wczesnym okresie pooperacyjnym (75%). Pozostałe obserwowano przez okres 1-125 miesięcy (śr. 45,7 ± 35,8) po zabiegu. Na podstawie analizy wyników badań echokardiograficznych, a u 16 dzieci także hemodynamicznych, zidentyfikowano pacjentów z nieprawidłowościami pooperacyjnymi, wymagających powtórnych zabiegów. U dzieci tych ocenie poddano typ nieprawidłowości, jej częstość oraz rodzaj i wynik podjętego leczenia w odniesieniu do wieku wykonania korekcji całkowitej.
Wyniki: Zabiegów reinterwencyjnych wymagało 21 dzieci (9,1%), w tym 12,9% najwcześniej operowanych, 7,5% dzieci z grupy średniej i 8% spośród najstarszych. Czas od korekcji doreinterwencji wynosił 0,03-76 miesięcy, (śr. 21 ± 21,8). U 18 dzieci wykonano reoperacje
(u 10 - z powodu resztkowych ubytków międzykomorowych, u 7 - z powodu znacznego zwężenia drogi wypływu z prawej komory, u 3 - z powodu zwężeń gałęzi tętnicy płucnej,
u 2 - z powodu tętniaków pnia tętnicy płucnej, u 1 - z powodu znacznej niedomykalności zastawki trójdzielnej i u 1 - z powodu dużych tętnic krążenia obocznego), a u 3 spośród
4 wykonano skuteczną plastykę balonową obwodowych zwężeń tętnicy płucnej. Sześć miesięcy po reinterwencji zmarło 1 dziecko (4,76%) z powodu powikłań infekcyjnych i prawokomorowej niewydolności serca.
Wnioski: Zabiegi reinterwencyjne po korekcji TOF u dzieci we wczesnym i pośrednim okresie obserwacji są rzadkie i obarczone niewielkim ryzykiem, a wyniki leczenia są zadowalające. (Folia Cardiol. 2001; 8: 575–580
All-sky Search for High-Energy Neutrinos from Gravitational Wave Event GW170104 with the ANTARES Neutrino Telescope
Advanced LIGO detected a significant gravitational wave signal (GW170104)
originating from the coalescence of two black holes during the second
observation run on January 4, 2017. An all-sky high-energy
neutrino follow-up search has been made using data from the ANTARES neutrino
telescope, including both upgoing and downgoing events in two separate
analyses. No neutrino candidates were found within s around the GW
event time nor any time clustering of events over an extended time window of
months. The non-detection is used to constrain isotropic-equivalent
high-energy neutrino emission from GW170104 to less than
erg for a spectrum
The ANTARES Collaboration: Contributions to ICRC 2017 Part I: Neutrino astronomy (diffuse fluxes and point sources)
Papers on neutrino astronomy (diffuse fluxes and point sources, prepared for
the 35th International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by
the ANTARES Collaboratio
The ANTARES Collaboration: Contributions to ICRC 2017 Part III: Searches for dark matter and exotics, neutrino oscillations and detector calibration
Papers on the searches for dark matter and exotics, neutrino oscillations and
detector calibration, prepared for the 35th International Cosmic Ray Conference
(ICRC 2017, Busan, South Korea) by the ANTARES Collaboratio
The ANTARES Collaboration: Contributions to ICRC 2017 Part II: The multi-messenger program
Papers on the ANTARES multi-messenger program, prepared for the 35th
International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by the
ANTARES Collaboratio
EURADOS Strategic Research Agenda 2020: Vision for the Dosimetry of Ionising Radiation
\ua9 The Author(s) 2021. Published by Oxford University Press. Since 2012, the European Radiation Dosimetry Group (EURADOS) has developed its Strategic Research Agenda (SRA), which contributes to the identification of future research needs in radiation dosimetry in Europe. Continued scientific developments in this field necessitate regular updates and, consequently, this paper summarises the latest revision of the SRA, with input regarding the state of the art and vision for the future contributed by EURADOS Working Groups and through a stakeholder workshop. Five visions define key issues in dosimetry research that are considered important over at least the next decade. They include scientific objectives and developments in (i) updated fundamental dose concepts and quantities, (ii) improved radiation risk estimates deduced from epidemiological cohorts, (iii) efficient dose assessment for radiological emergencies, (iv) integrated personalised dosimetry in medical applications and (v) improved radiation protection of workers and the public. This SRA will be used as a guideline for future activities of EURADOS Working Groups but can also be used as guidance for research in radiation dosimetry by the wider community. It will also be used as input for a general European research roadmap for radiation protection, following similar previous contributions to the European Joint Programme for the Integration of Radiation Protection Research, under the Horizon 2020 programme (CONCERT). The full version of the SRA is available as a EURADOS report (www.eurados.org)
The Antares Collaboration : Contributions to the 34th International Cosmic Ray Conference (ICRC 2015, The Hague)
The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. Located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore, its main goal is the search for astrophysical high energy neutrinos. In this paper we collect the 21 contributions of the ANTARES collaboration to the 34th International Cosmic Ray Conference (ICRC 2015). The scientific output is very rich and the contributions included in these proceedings cover the main physics results, ranging from steady point sources, diffuse searches, multi-messenger analyses to exotic physics
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