486 research outputs found
CIVIC EPISTEMOLOGIES – Development of a Roadmap for Citizen Researchers in the Age of Digital Culture
The CIVIC EPISTEMOLOGIES project investigates citizen science and crowdsourcing in the domain of the research in Digital Cultural Heritage and Humanities (DCHH). The ultimate aim is to produce a validated Roadmap indicating the suggested direction that the deployment of services and infrastructures should take, in order to support the participation of citizens in the research processes and the participation of creative industries in the exploitation of digital cultural content. The case of DCHH is particularly relevant because of the major cross-cutting role that the humanities play in European research and innovation, recently acknowledged in a clear way in the Horizon2020 Community Programme for Research and Innovation. Cultural heritage and humanities also represent a subject area in which citizens are particularly active, counting several – still spread - experiences of their involvement in recording, annotating and cataloguing activities on an individual or group basis, as volunteers and amateurs. The case of broadening e-Infrastructure deployment to support the participation of citizens to DCHH research, even if holding a strong impact potential for social cohesion and job development, is not yet fully explored. The paper discusses about the multidisciplinary approach to citizen science and how this method can contribute to the benefit of many scientific domains, research communities, and technology advancements as well as delivering novel social and economic impact
The Role of Multiple Electron Processes for Fast Ion H₂O Collisions
In this work, collision processes between C6+, O8+ and Si13+ ions and H2O molecules that lead to target ionization are studied by means of the classical trajectory Monte Carlo method. We employ an 8-electron model in which the H2O electron densities and energies dynamically adapt during ionization processes to those corresponding to the H2Oq+ ions by assuming vertical transitions between the different molecular ionic states. Net total ionization cross sections and single differential cross sections in energy and angle are shown for 4 MeV/u projectiles and compared to available experimental data and theoretical predictions from distorted wave models
Study of the light-induced metal-insulator transition in SrTiO3 by photoresistance spectroscopy
Photoresistivity and its spectral response has been systematically studied in oxygen deficient SrTiO3 single crystals for a wide range of resistivities, ρ, and carrier densities, n. At roomtemperature we have found a persistent photoresistance that gradually decreases as ρ is diminished or n is increased in addition to relaxation times of seconds to a few minutes suggesting that trapping of carriers is playing a major role. An analysis of the photoresistance excitation spectra shows two distinctive features that are related to the indirect gap of SrTiO3 at (3.25 ± 0.04) eV and to a direct transition at (3.40 ± 0.03) eV. The photoresistive crystals present a temperature dependent resisitivity under illumination that experiences a metal-insulator transition below T ∼ 85 K. Lowtemperature photoresistance spectrum reveals as a suitable technique to understand the origin of this transition, pointing to an enhanced efficiency of the ∼ 3.25 eV gap to promote electrons to the bottom of the conduction band.Fil: Bridoux, German. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Villafuerte, Manuel Jose. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ferreyra, J. M.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Bachi, N.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Figueroa, C. A.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; ArgentinaFil: Heluani, S. P.. Universidad Nacional de Tucumán. Facultad de Ciencias Exactas y Tecnología. Departamento de Física. Laboratorio de Física del Solido; Argentin
A common core RNP structure shared between the small nuclear box C/D RNPs and the spliceosomal U 4 snRNP.
AbstractThe box C/D snoRNAs function in directing 2′-O-methylation and/or as chaperones in the processing of ribosomal RNA. We show here that Snu13p (15.5kD in human), a component of the U4/U6.U5 tri-snRNP, is also associated with the box C/D snoRNAs. Indeed, genetic depletion of Snu13p in yeast leads to a major defect in RNA metabolism. The box C/D motif can be folded into a stem-internal loop-stem structure, almost identical to the 15.5kD binding site in the U4 snRNA. Consistent with this, the box C/D motif binds Snu13p/15.5kD in vitro. The similarities in structure and function observed between the U4 snRNP (chaperone for U6) and the box C/D snoRNPs raises the interesting possibility that these particles may have evolved from a common ancestral RNP
Discovery of the Binary Pulsar PSR B1259-63 in Very-High-Energy Gamma Rays around Periastron with H.E.S.S
We report the discovery of very-high-energy (VHE) gamma-ray emission of the
binary system PSR B1259-63/SS 2883 of a radio pulsar orbiting a massive,
luminous Be star in a highly eccentric orbit. The observations around the 2004
periastron passage of the pulsar were performed with the four 13 m Cherenkov
telescopes of the H.E.S.S. experiment, recently installed in Namibia and in
full operation since December 2003. Between February and June 2004, a gamma-ray
signal from the binary system was detected with a total significance above 13
sigma. The flux was found to vary significantly on timescales of days which
makes PSR B1259-63 the first variable galactic source of VHE gamma-rays
observed so far. Strong emission signals were observed in pre- and
post-periastron phases with a flux minimum around periastron, followed by a
gradual flux decrease in the months after. The measured time-averaged energy
spectrum above a mean threshold energy of 380 GeV can be fitted by a simple
power law F_0(E/1 TeV)^-Gamma with a photon index Gamma =
2.7+-0.2_stat+-0.2_sys and flux normalisation F_0 = (1.3+-0.1_stat+-0.3_sys)
10^-12 TeV^-1 cm^-2 s^-1. This detection of VHE gamma-rays provides unambiguous
evidence for particle acceleration to multi-TeV energies in the binary system.
In combination with coeval observations of the X-ray synchrotron emission by
the RXTE and INTEGRAL instruments, and assuming the VHE gamma-ray emission to
be produced by the inverse Compton mechanism, the magnetic field strength can
be directly estimated to be of the order of 1 G.Comment: 10 pages, 8 figures, accepted in Astronomy and Astrophysics on 2 June
2005, replace: document unchanged, replaced author field in astro-ph entry -
authors are all members of the H.E.S.S. collaboration and three additional
authors (99+3, see document
A pan-European review of good practices in early intervention safeguarding practice with children, young people and families : evidence gathering to inform a multi-disciplinary training programme (the ERICA project) in preventing child abuse and neglect in seven European countries
Funded by the Rights, Equality and Citizenship Programme of the European Commission (European Commission 2019–2021).Child maltreatment has detrimental social and health effects for individuals, families and communities. The ERICA project is a pan-European training programme that equips non-specialist threshold practitioners with knowledge and skills to prevent and detect child maltreatment. This paper describes and presents the findings of a rapid review of good practice examples across seven participating countries including local services, programmes and risk assessment tools used in the detection and prevention of child maltreatment in the family. Learning was applied to the development of the generic training project. A template for mapping the good practice examples was collaboratively developed by the seven participating partner countries. A descriptive data analysis was undertaken organised by an a priori analysis framework. Examples were organised into three areas: programmes tackling child abuse and neglect, local practices in assessment and referral, risk assessment tools. Key findings were identified using a thematic approach. Seventy-two good practice examples were identified and categorised according to area, subcategory and number. A typology was developed as follows: legislative frameworks, child health promotion programmes, national guidance on child maltreatment, local practice guidance, risk assessment tools, local support services, early intervention programmes, telephone or internet-based support services, COVID-19 related good practices. Improved integration of guidance into practice and professional training in child development were highlighted as overarching needs. The impact of COVID-19 on safeguarding issues was apparent. The ERICA training programme formally responded to the learning identified in this international good practice review.Publisher PDFPeer reviewe
Observations of Mkn 421 in 2004 with H.E.S.S. at large zenith angles
Mkn 421 was observed during a high flux state for nine nights in April and
May 2004 with the fully operational High Energy Stereoscopic System (H.E.S.S.)
in Namibia. The observations were carried out at zenith angles of
60--65, which result in an average energy threshold of 1.5 TeV
and a collection area reaching 2~km at 10~TeV. Roughly 7000 photons from
Mkn~421 were accumulated with an average gamma-ray rate of 8 photons/min. The
overall significance of the detection exceeds 100 standard deviations. The
light-curve of integrated fluxes above 2~TeV shows changes of the diurnal flux
up to a factor of 4.3. For nights of high flux, intra-night variability is
detected with a decay time of less than 1 hour. The time averaged energy
spectrum is curved and is well described by a power-law with a photon index
\egamm and an exponential cutoff at \ecut~TeV and an average integral flux
above 2~TeV of 3 Crab flux units. Significant variations of the spectral shape
are detected with a spectral hardening as the flux increases. Contemporaneous
multi-wavelength observations at lower energies (X-rays and gamma-rays above
~GeV) indicate smaller relative variability amplitudes than seen
above 2~TeV during high flux state observed in April 2004.Comment: 5 pages, 4 figures, published in A&
Very high energy gamma rays from the direction of Sagittarius A*.
We report the detection of a point-like source of very high energy (VHE) -rays coincident within 1' of Sgr A *, obtained with the HESS array of Cherenkov telescopes. The -rays exhibit a power-law energy spectrum with a spectral index of and a flux above the 165 GeV threshold of m -2 s -1. The measured flux and spectrum differ substantially from recent results reported in particular by the CANGAROO collaboration
A possible association of the new VHE gamma-ray source HESS J1825--137 with the pulsar wind nebula G18.0--0.7
We report on a possible association of the recently discovered very
high-energy -ray source HESS J1825--137 with the pulsar wind nebula
(commonly referred to as G 18.0--0.7) of the year old
Vela-like pulsar PSR B1823--13. HESS J1825--137 was detected with a
significance of 8.1 in the Galactic Plane survey conducted with the
H.E.S.S. instrument in 2004. The centroid position of HESS J1825--137 is offset
by 11\arcmin south of the pulsar position. \emph{XMM-Newton} observations have
revealed X-ray synchrotron emission of an asymmetric pulsar wind nebula
extending to the south of the pulsar. We argue that the observed morphology and
TeV spectral index suggest that HESS J1825--137 and G 18.0--0.7 may be
associated: the lifetime of TeV emitting electrons is expected to be longer
compared to the {\it XMM-Newton} X-ray emitting electrons, resulting in
electrons from earlier epochs (when the spin-down power was larger)
contributing to the present TeV flux. These electrons are expected to be
synchrotron cooled, which explains the observed photon index of , and
the longer lifetime of TeV emitting electrons naturally explains why the TeV
nebula is larger than the X-ray size. Finally, supernova remnant expansion into
an inhomogeneous medium is expected to create reverse shocks interacting at
different times with the pulsar wind nebula, resulting in the offset X-ray and
TeV -ray morphology.Comment: 5 pages, 3 figures, to appear in Astronomy and Astrophysics Letter
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