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  • Springer  (86,929)
  • American Chemical Society  (71,475)
  • 2005-2009  (158,404)
  • 1985-1989
  • 1980-1984
  • 2009  (87,098)
  • 2005  (71,306)
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  • 2005-2009  (158,404)
  • 1985-1989
  • 1980-1984
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  • 1
    Unknown
    New York : Springer
    Keywords: Computer engineering. ; Computer security. ; Electronic data processing, Distributed processing.
    Pages: xx, 239 p.
    ISBN: 0-387-23917-0
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  • 2
    Publication Date: 2020-11-17
    Description: An efficient procedure is proposed in order to define realistic lower limits of velocity errors of a non-permanent GPS station (NPS), i.e. a station where the antenna is installed and operates for short time periods, typically 10-20 days per year. Moreover, the proposed method is aimed at being independent from the standard GPS data processing. The key is to appropriately subsample the coordinate time series of several continuous GPS stations (CGPSs) situated nearby or inside the considered NPS network, in order to simulate the NPS behavior and to estimate the velocity errors associated with the subsampling procedure. The obtained data are therefore used as lower limits to accept or correct the error estimates provided by standard data processing. The proposed approach is applied to data from the dense non-permanent network in the Central Apennine of Italy based on a sequence of solutions for the overlapping time spans 1999-2003, 1999-2004, 1999-2005 and 1999-2007. Both the original and error-corrected velocity patterns are used to compute the strain rate fields. The comparison between the corresponding results reveals large differences that could lead to divergent interpretations about the kinematics of the study area.
    Description: Published
    Description: 249–261
    Description: 2T. Deformazione crostale attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Non-permanent GPS Stations ; Velocity Field ; Strain Rate ; Survey Optimization; ; Solution Sequence ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2020-12-23
    Description: In July 1998, an Mw = 6.2 earthquake struck the islands of Faial, Pico and San Jorge (in the Azores Archipelago), registering VIII on the Modified Mercalli Intensity scale and causing major destruction in the northeastern part of Faial. The main shock was located offshore, 8 km North East of the island, and it triggered a seismic sequence that lasted for several weeks. The existing data for this earthquake include both the general tectonic environment of the region and the teleseismic information. This is accompanied by one strong-motion record obtained 15 km from the epicentre, the epicentre location of aftershocks, and a large collection of the damage inflicted to the building stock (as poor rubble masonry, of 2-3 storeys). The present study was carried out in two steps: first, with a finite-fault stochastic simulation method of ground motion at sites throughout the affected islands, for two possible locations of the rupturing fault and for a large number of combinations of rupture mechanisms (as a parametric analysis); secondly, the damage to buildings was modelled using a well-known macroseismic method that considers the building typologies and their associated vulnerabilities. The main intent was to integrate different data (geological, seismological and building features) to produce a scenario model to reproduce and justify the level of damage generated during the Faial earthquake. Finally, through validation of the results provided by these different approaches, we obtained a complete procedure for the parameters of a first model for the production of seismic damage scenarios for the Azores Islands region.
    Description: Published
    Description: 361–381
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: Stochastic finite-fault scenarios ; Building damage assessment ; 9th July Faial earthquake ; Azores Islands ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2021-07-13
    Description: The aim of this study was to investigate the microbial community thriving at two shallow hydrothermal vents off Panarea Island (Italy). Physico-chemical characteristics of thermal waters were examined in order to establish the effect of the vents on biodiversity of both Bacteria and Archaea. Water and adjacent sediment samples were collected at different times from two vents, characterised by different depth and temperature, and analysed to evaluate total microbial abundances, sulphuroxidising and thermophilic aerobic bacteria. Total microbial abundances were on average of the order of 105 cells ml-1, expressed as picoplanktonic size fraction. Picophytoplanktonic cells accounted for 0.77–3.83% of the total picoplanktonic cells. The contribution of bacterial and archaeal taxa to prokaryotic community diversity was investigated by PCR–DGGE fingerprinting method. The number of bands derived from bacterial DNA was highest in the DGGE profiles of water sample from the warmest and deepest site (site 2). In contrast, archaeal richness was highest in the water of the coldest and shallowest site (site 1). Sulphur-oxidising bacteria were detected by both culture- dependent and -independent methods. The primary production at the shallow hydrothermal system of Panarea is supported by a complex microbial community composed by phototrophs and chemolithotrophs.
    Description: Published
    Description: 199-212
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: hydrothermal vents ; bacteria ; geochemistry ; fluids ; 03. Hydrosphere::03.03. Physical::03.03.01. Air/water/earth interactions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2020-11-23
    Description: Abstract: The simultaneous solution of the Planck equation (involving the widely used “dual-band” technique) using two shortwave infrared (SWIR) bands allows for an estimate of the fractional area of the hottest part of an active lava flow (fh), and the background temperature of the cooler crust (Tc). The use of a high spectral and spatial resolution imaging spectrometer with a wide dynamic range of 15 bits (DAIS 7915) in the wavelength range from 0.501 to 12.67 µm resulted in the identification of crustal temperature and fractional areas for an intra-crater hot spot at Mount Etna, Italy. This study indicates the existence of a relationship between these Tc and fh extracted from DAIS and Landsat TM data. When the dual band equation system is performed on a lava flow, a logarithmic distribution is obtained from a plot of the fractional area of the hottest temperature versus the temperature of the cooler crust. An entirely different distribution is obtained over active degassing vents, where increases in Tc occur without any increase in fh. This result indicates that we can use scatter plots of Tc vs. fh to discriminate between different types of volcanic activity, in this case between degassing vents and lava flows, using satellite thermal data.
    Description: Published
    Description: 641–651
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Description: open
    Keywords: Mount Etna ; remote-sensing ; lava-flow ; degassing vent ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 6
    Publication Date: 2020-11-16
    Description: Geological, geophysical and geotechnical investigations, for the characterization of the strong-motion recording sitesmanaged by the ItalianCivil Protection, have been carried out in the framework of the project “Italian strong-motion database in the period 1972–2004”. The project aimed at creating an updated database of strong-motion data acquired in Italy by different institutions in the time span 1972–2004, and at improving the quality of disseminated data. This article illustrates the state of the recording site characterization before the beginning of the project, explains the criteria adopted to select the sites where geophysical/ geotechnical investigation have been performed and describes the results of the promoted field surveys.
    Description: Published
    Description: 1189–1207
    Description: 4IT. Banche dati
    Description: JCR Journal
    Description: open
    Keywords: site ; characterization ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
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  • 7
    Publication Date: 2021-03-01
    Description: On September 6, 2002, aML =5.6 earthquake, occurring some tens of kilometres offshore from the Northern Sicilian coast (Southern Tyrrhenian Sea), slightly damaged the city of Palermo and surroundings (degree 6 in the European Macroseismic Scale 1998). The macroseismic investigation of the shock and a detailed study of effects of the main earthquakes which affected Palermo in the past have been performed in order to evaluate the seismic response of the city. Moreover, the comparison of the recent event, which is instrumentally constrained, with historical earthquakes allows us to infer new insights on the seismogenic sources of the area, that seem located offshore in the Tyrrhenian sea. In the last 500 years, Palermo has never been completely destroyed but has suffered effects estimated between intensities 6 and 8 EMS-98 many times (1693, 1726, 1751, 1823, 1940, 1968, 2002). The damage scenarios of the analysed events have shown that damage distribution is strongly conditioned by soil response in the different parts of the city and by a high building vulnerability, mainly in the historical centre and in the south-eastern zone of the modern city. As a matter of fact, Palermo has always suffered greater effects than those reported for other nearby localities. The hazard assessment obtained using observed site intensities has shown that the probability of occurrence for intensity 8 (the strongest intensity observed in Palermo) exceeds 99% for 550 years, while the estimated mean return period is 152 ± 40 years. These results, in connection with building vulnerability due to the urban expansion before the introduction of seismic code, suggest that the city is exposed to a relatively high seismic risk.
    Description: Published
    Description: 525-543
    Description: partially_open
    Keywords: intensity ; damage ; earthquakes ; Italy ; macroseismics ; Palermo ; seismic hazard ; vulnerability ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2017-04-03
    Description: We compare the results obtained from the modelling of EDM, GPS, levelling and tilt data measured in the first part of the 19911993 eruption at Etna to the InSAR data acquired during the second part. The geodetic changes are very marked in the first half of the eruption and constrain a deflation source located at a few kilometers of depth ( 3 km b.s.l.), in agreement with other independent geophysical evidence. SAR data, available during the second part of the eruption, were analysed for different time intervals in the second part of the eruption. The interpretation of SAR interferograms reveals a large-scale but less marked deflation of the volcano that could be caused by a deeper source. This second source is in accord with a second deeper anomaly revealed by recent seismic investigations. The combination of geodetic data modelling and SAR images suggests a complex plumbing system composed at least of two possible storage regions located at different depths.
    Description: Published
    Description: 1345-1357
    Description: partially_open
    Keywords: Geodesy ; SAR Interferometry ; ground deformation ; Mt. Etna volcano ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
    Publication Date: 2017-04-04
    Description: Analysis of the historical records of Etnas eruptive activity for the past three centuries shows that, after the large 1669 eruption, a period of about 60 years of low-level activity followed. Starting from 1727, explosive activity (strombolian, lava fountaining and subplinian) at the summit crater increased exponentially to the present day. Since 1763, the frequency of flank eruptions also increased and this value remained high until 1960; afterward it further increased sharply. In fact, the number of summit and flank eruptions between 1961 and 2003 was four times greater than that of the pre-1960 period. This long-term trend of escalating activity rules out a pattern of cyclic behaviour of the volcano. We propose instead that the 16702003 period most likely characterises a single eruptive cycle which began after the large 1669 eruption and which is still continuing. On the basis of the eruptive style, two distinct types of flank eruptions are recognised: Class A and Class B. Class A eruptions are mostly effusive with associated weak strombolian activity; Class B eruptions are characterised by effusive activity accompanied by intense, long-lasting, strombolian and lava fountaining activity that produces copious tephra fallouts, as during the 2001 and 20022003 eruptions. Over the past three centuries, seven Class B eruptions have taken place with vents located mainly on the south-eastern flank, indicating that this sector of the volcano is a preferential zone for the intrusion of volatile-rich magma rising from the deeper region of the Etna plumbing system.
    Description: Published
    Description: 732-742
    Description: partially_open
    Keywords: Etna ; Historical record ; Summit activity ; Flank eruptions ; Eruptive behaviour ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
    Publication Date: 2017-04-04
    Description: The Monte Nuovo eruption is the most recent event that occurred at Phlegrean Fields (Italy) and lasted from 29 September to 6 October 1538. It was characterized by 2 days of quasi-sustained phreatomagmatic activity generating pumice-bearing pyroclastic density currents and forming a 130-m-high tuff cone (Lower Member deposits). The activity resumed after a pause of 2 days with two discrete Vulcanian explosions that emplaced radially distributed, scoria-bearing pyroclastic flows (Upper Member deposits). The juvenile products of Lower and Upper Members are, respectively, phenocryst-poor, light-coloured pumice and dark scoria fragments with K-phonolitic bulk compositions, identical in terms of both major and trace elements. Groundmass is formed by variable proportions of K-feldspar and glass, along with minor sodalite and Fe-Ti oxide present in the most crystallized samples. Investigations of groundmass compositions and textures were performed to assess the mechanisms of magma ascent, degassing and fragmentation along the conduit and implications for the eruptive dynamics. In pumice of the Lower Member groundmass crystal content increases from 13 to 28 vol% from the base to the top of the sequence. Products of the Upper Member consist of clasts with a groundmass crystal content between 30 and 40 vol% and of totally crystallized fragments. Crystal size distributions of groundmass feldspars shift from a single population at the base of the Lower Member to a double population in the remaining part of the sequence. The average size of both populations regularly increases from the Lower to the Upper Member. Crystal number density increases by two orders of magnitude from the Lower to the Upper Member, suggesting that nucleation dominated during the second phase of the eruption. The overall morphological, compositional and textural data suggest that the juvenile components of the Monte Nuovo eruption are likely to record variations of the magma properties within the conduit. The different textures of pumice clasts from the Lower Member possibly reflect horizontal gradients of the physical properties (P, T) of the ascending magma column, while scoriae from the second phase are thought to result from the disruption of a slowly rising plug crystallizing in response to degassing. In particular, crystal size distribution data point to syn-eruptive degassing-induced crystallization as responsible for the transition in eruptive style from the first to the second phase of the eruption. This mechanism not only has been proved to profoundly affect the dynamics of dome-forming calc-alkaline eruptions, but may also have a strong influence in driving the eruption dynamics of alkaline magmas of intermediate to evolved compositions.
    Description: Published
    Description: 601-621
    Description: reserved
    Keywords: Phlegrean Fields ; Vulcanian explosion ; Degassing ; Groundmass crystallization ; Eruption dynamics ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 11
    Publication Date: 2017-04-04
    Description: In this work we present seismological and ground deformation evidence for the phase preparing the July 18 to August 9, 2001 flank eruption at Etna. The analysis performed, through data from the permanent seismic and ground deformation networks, highlighted a strong relationship between seismic strain release at depth and surface deformation. This joint analysis provided strong constraints on the magma rising mechanisms. We show that in the last ten years, after the 1991–1993 eruption, an overall accumulation of tension has affected the volcano. Then we investigate the months preceding the 2001 eruption. In particular, we analyse the strong seismic swarm on April 20–24, 2001, comprising more than 200 events (Mmax = 3.6) with prevalent dextral shear fault mechanisms in the western flank. The swarm showed a ca. NE-SW earthquake alignment which, in agreement with previous cases, can be interpreted as the response of the medium to an intrusive process along the approximately NNW-SSE volcano-genetic trend. These mechanisms, leading to the July 18 to August 9, 2001 flank eruption, are analogous to ones observed some months before the 1991–1993 flank eruption and, more recently, in January 1998 before the February-November 1999 summit eruption.
    Description: Published
    Description: 1469-1487
    Description: partially_open
    Keywords: Ground deformation ; volcano seismology ; Mt. Etna Volcano ; intrusive mechanism ; 04. Solid Earth::04.03. Geodesy::04.03.01. Crustal deformations ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 12
    Publication Date: 2017-04-04
    Description: The objective of the COST296 Action MIERS (Mitigation of Ionospheric Effects on Radio Systems) is to develop an increased knowledge of the effects imposed by the ionosphere on practical radio systems, and for the development and implementation of techniques to mitigate the deleterious effects of the ionosphere on such systems (http://www.cost296.rl.ac.uk). The COST296 Community contributes to the international efforts of IHY with scientific and outreach activities as well. After the realization of a web site hosted by Istituto Nazionale di Geofisica e Vulcanologia (INGV), developed also to promote the ionospheric physics to the open public, the COST296 Community supported an initiative addressed to the pupils of the primary school of several European Countries: the realization of a school-calendar dedicated to the Sun and to the Sun-Earth connections.
    Description: Published
    Description: 63-67
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: 5.9. Formazione e informazione
    Description: JCR Journal
    Description: reserved
    Keywords: E/PO ; Space weather ; 05. General::05.03. Educational, History of Science, Public Issues::05.03.99. General or miscellaneous ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 13
    Publication Date: 2017-04-04
    Description: The complex geochemical interactions in the groundwater of the industrial area of S ˇ alek Valley (Slovenia) between natural and anthropogenic fluids were studied by means of major (Ca, Mg, Na, K, HCO3 -, Cl- and SO4 2-) and trace elements’ (As , Cd, Cu, Pb, Zn, Hg, Se and V) abundances, geochemical classification and statistical analysis of data. Cation abundances indicate mixing between a dolomitic end-member and an evaporitic or geothermal end-member. Anion abundances indicate mixing between bicarbonate waters and either sulphateenriched waters (suggesting hydrothermalism) or chlorinerich waters. Principal component analysis (PCA) allowed the extraction of seven factors, which describe, respectively: water–rock interaction mainly on dolomitic rocks; redox conditions of water; Cd–Zn enrichment in chlorinerich waters (probably from industrial wastes); hydrothermal conditions in waters close to major faults; Pb and Cu pollution; V and K enrichments, indicating their common organic source; the role of partial pressure of CO2 dissolved in water, which is highest in three wells with bubbling gases. Average underground discharge rates of solutes from the Valley range between 0.09 t/a (V) and 1.8 9 104 t/a (HCO3 -) and indicate how natural fluids can significantly contribute to the levels of elements in the environment, in addition to the amount of elements released by human activities.
    Description: Ministry of Foreign Affairs of Italy and Ministry of Superior Instruction, Science and Technology of Slovenia. Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palermo
    Description: Published
    Description: 75-89
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: reserved
    Keywords: groundwater ; Slovenia ; geothermal systems ; Principal Component Analysis ; pollution ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters
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  • 14
    Publication Date: 2017-04-04
    Description: The Italian strong-motion database was created during a joint project between Istituto Nazionale di Geofisica e Vulcanologia (INGV, Italian Institute for Geophysics and Vulcanology) and Dipartimento della Protezione Civile (DPC, Italian Civil Protection). The aim of the project was the collection, homogenization and distribution of strong motion data acquired in Italy in the period 1972-2004 by different institutions, namely Ente Nazionale per l’Energia Elettrica (ENEL, Italian electricity company), Ente per le Nuove tecnologie, l’Energia e l’Ambiente (ENEA, Italian energy and environment organization) and DPC. Recently the strong-motion data relative to the 23th December 2009, Parma (Mw=5.4 and Mw=4.9) and to the 2009 L’Aquila sequence (13 earthquakes with 4.1Mw6.3) were included in the ITACA database (beta release). The database contains 7038 waveforms from analog and digital instruments, generated by 1019 earthquakes with magnitude up to 6.9 and can be accessed on-line at the web site http://itaca.mi.ingv.it. The strong motion data are provided in the unprocessed and processed versions. This article describes the steps followed to process the acceleration time series recorded by analogue and digital instruments. The procedures implemented involve: baseline removal, instrumental correction, band pass filtering with acausal filters, integration of the corrected acceleration in order to obtain velocity and displacement waveforms, computation of acceleration response spectra and strong motion parameters. This procedure is applied to each accelerogram, is realised to preserve the low frequency content of the records.
    Description: In press
    Description: 5.2. TTC - Banche dati di sismologia strumentale
    Description: JCR Journal
    Description: open
    Keywords: strong-motion ; processing ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 15
    Publication Date: 2017-04-04
    Description: Ground deformation occurring on the southern flank of Mt Etna volcano during the JulyAugust 2001 eruption was monitored by GPS measurements along an EW profile crossing the fissure system. This profile was measured eight times during the eruption, using the 'stop and go' semi-kinematic technique. Horizontal and vertical displacements between GPS surveys are reported for each station. The most significant event is a deformation episode occurring during the first week of the eruption, between 2527 July. Displacements were measured on benchmarks close to the eruptive fissure and the tensile 1989 fracture. Data inversions for measured displacements were performed using the Okada model. The model shows the narrowing of the 2001 dyke accompanied by a dextral dislocation along an east-dipping fault, parallel to the 1989 fracture.
    Description: Published
    Description: 336-341
    Description: partially_open
    Keywords: GPS ; Ground deformation ; Modelling ; Volcano monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
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  • 16
    Publication Date: 2017-04-04
    Description: The 200203 Mt Etna flank eruption began on 26 October 2002 and finished on 28 January 2003, after three months of continuous explosive activity and discontinuous lava flow output. The eruption involved the opening of eruptive fissures on the NE and S flanks of the volcano, with lava flow output and fire fountaining until 5 November. After this date, the eruption continued exclusively on the S flank, with continuous explosive activity and lava flows active between 13 November and 28 January 2003. Multi-disciplinary data collected during the eruption (petrology, analyses of ash components, gas geochemistry, field surveys, thermal mapping and structural surveys) allowed us to analyse the dynamics of the eruption. The eruption was triggered either by (i) accumulation and eventual ascent of magma from depth or (ii) depressurisation of the edifice due to spreading of the eastern flank of the volcano. The extraordinary explosivity makes the 200203 eruption a unique event in the last 300 years, comparable only with La Montagnola 1763 and the 2001 Lower Vents eruptions. A notable feature of the eruption was also the simultaneous effusion of lavas with different composition and emplacement features. Magma erupted from the NE fissure represented the partially degassed magma fraction normally residing within the central conduits and the shallow plumbing system. The magma that erupted from the S fissure was the relatively undegassed, volatile-rich, buoyant fraction which drained the deep feeding system, bypassing the central conduits. This is typical of most Etnean eccentric eruptions. We believe that there is a high probability that Mount Etna has entered a new eruptive phase, with magma being supplied to a deep reservoir independent from the central conduit, that could periodically produce sufficient overpressure to propagate a dyke to the surface and generate further flank eruptions.
    Description: Published
    Description: 314-330
    Description: partially_open
    Keywords: Multi-disciplinary study ; Mount Etna ; 2002–03 eruption ; Eccentric eruptions ; Flank activity ; Etna feeding system ; Volcanic processes ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 17
    Publication Date: 2017-04-04
    Description: An anisotropic attenuation law, based on an anisotropic characterization of intensity distribution for seismogenic zones, is proposed. This approach, that distinguishes itself for its consistency to the observed data, initially reconfigured by filtering procedures, is particularly suitable for seismic hazard evaluation.
    Description: Published
    Description: 707-714
    Description: partially_open
    Keywords: Attenuation law ; virtual intensity distribution ; seismic hazard ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 18
    Publication Date: 2017-04-04
    Description: In the Rocca Busambra area (mid-west Sicily, Italy), from November 1999 to July 2002, 23 water points including wells and springs were sampled and studied for their chemical and isotopic compositions. Two rain gauges were also installed at different altitudes, and rainwater was collected monthly to determine the isotopic composition. The obtained results revealed the Rocca Busambra carbonate complex as being the main recharge area on account of its high permeability value. From a chemical view point, two main groups of water can be distinguished: calcium– magnesium–bicarbonate-type and calcium–magnesium– chloride–sulphate-type waters. The first group reflects the dissolution of the carbonate rocks; the second group probably originates from circulation within flyschoid sediments. Three water wells differ from the other samples due to their relatively high Na and K content, which probably is to be referred to a marked interaction with the ‘‘Calcareniti di Corleone’’ formation, which is rich in glauconite [(K, Na)(Fe3+, Al, Mg)2(Si, Al)4O10(OH)2]. In accordance with WHO guidelines for drinking water (2004), almost all the samples collected can be considered drinkable, with the exception of four of them, whose NO3 -, F- and Na+ contents exceed the limits. On the contrary, the sampled groundwater studied is basically suitable for irrigation.
    Description: Published
    Description: 885-898
    Description: 2.4. TTC - Laboratori di geochimica dei fluidi
    Description: JCR Journal
    Description: reserved
    Keywords: Water quality ; Environmental isotopes ; Geochemistry ; Sicily ; 03. Hydrosphere::03.01. General::03.01.01. Analytical and numerical modeling
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 19
    Publication Date: 2017-04-04
    Description: A modelling of the observed macroseismic intensity of historical and instrumental earthquakes in southern Spain is proposed, with the aim of determining the macroseismic parameters for seismic hazard evaluation in a region in which the characterization of intensity distribution of seismic events shows different levels of difficulty referable to the complex faults system of the area in study. The adopted procedure allows an analytical determination of epicenters and principal attenuation directions of earthquakes with a double level of verification with reference to the maximum shaking area and structural lineaments of the region, respectively. The analyses, carried out on a suitable number of events, highlight, therefore, some elements for a preliminary characterization of a seismic zonation on the basis of the consistency between seismic intensity distribution of earthquakes and corresponding structural framework.
    Description: Published
    Description: 747-760
    Description: partially_open
    Keywords: Attenuation directions ; southern Spain ; macroseismic intensity ; virtual intensity ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
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  • 20
    Publication Date: 2017-04-04
    Description: Flank instability and collapse are observed at many volcanoes. Among these, Mt. Etna is characterized by the spreading of its eastern and southern flanks. The eastern spreading area is bordered to the north by the EW-trending Pernicana Fault System (PFS). During the 20022003 Etna eruption, ground fracturing along the PFS migrated eastward from the NE Rift, to as far as the 18 km distant coastline. The deformation consisted of dextral en-echelon segments, with sinistral and normal kinematics. Both of these components of displacement were one order of magnitude larger (~1 m) in the western, previously known, portion of the PFS with respect to the newly surveyed (~9 km long) eastern section (~0.1 m). This eastern section is located along a pre-existing, but previously unknown, fault, where displaced man-made structures give overall slip rates (11.9 cm/year), only slightly lower than those calculated for the western portion (1.42.3 cm/year). After an initial rapid motion during the first days of the 20022003 eruption, movement of the western portion of the PFS decreased dramatically, while parts of the eastern portion continued to move. These data suggest a model of spreading of the eastern flank of Etna along the PFS, characterized by eruptions along the NE Rift, instantaneous, short-lived, meter-scale displacements along the western PFS and more long-lived centimeter-scale displacements along the eastern PFS. The surface deformation then migrated southwards, reactivating, one after the other, the NNWSSE-trending Timpe and Trecastagni faults, with displacements of ~0.1 and ~0.04 m, respectively. These structures, along with the PFS, mark the boundaries of two adjacent blocks, moving at different times and rates. The new extent of the PFS and previous activity over its full length indicate that the sliding eastern flank extends well below the Ionian Sea. The clustering of seismic activity above 4 km b.s.l. during the eruption suggests a deep décollement for the moving mass. The collected data thus suggests a significant movement (volume 〉1,100 km3) of the eastern flank of Etna, both on-shore and off-shore.
    Description: Published
    Description: 417-430
    Description: partially_open
    Keywords: Volcano spreading ; Fracturing ; Mt. Etna ; Pernicana Fault System ; NE Rift ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 21
    Publication Date: 2017-04-04
    Description: We have characterized pumice products belonging to the climactic phase of the 800-year-b.p. Quilotoa eruption. Bulk rock compositions, petrography, mineral, and glass chemistry and textural investigations were performed on the three end-member pumice types, namely white, gray, and mingled pumices. All the investigated pumice clasts are dacites characterized by the same bulk rock composition and mineralogical assemblage, but glass compositions and bulk textures change according to different pumice types. White pumice has higher crystallinity (~48 wt%), abundant euhedral pheno/microphenocrysts, no groundmass microlites, the most evolved glass compositions (7478 wt% SiO2), and heterogeneous vesicle populations marked by deformed and highly coalesced vesicles with thin walls. Gray pumice exhibits lower crystallinity (2936 wt%), abundant broken and/or resorbed crystals, ubiquitous groundmass phenocryst fragments and microlites, the widest range of glass compositions (6978 wt% SiO2), and quite homogeneous poorly deformed and coalesced vesicles with thicker walls. Mingled pumices are characterized by the alternation of bands or patches with white and gray pumice compositional and textural characteristics. We attribute heterogeneities in glass compositions and crystal and vesicle textures to processes occurring within volcanic conduits as magma is ascending to the surface. In particular, the above observations and results are consistent with an origin of a gray magma by heating of the original white magma in a strongly sheared region of the conduit because of a mechanism of viscous dissipation and crystal grinding and resorption at the conduit walls. The less viscous gray magma, therefore, would enable the onset and preservation of a high mass flux of the eruption otherwise difficult to explain for highly viscous crystal-rich dacitic magmas.
    Description: Published
    Description: 307-321
    Description: partially_open
    Keywords: Plinian eruption ; Crystal-rich magma ; Crystal grinding ; Pumice types ; Viscous dissipation ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 22
    Publication Date: 2017-04-04
    Description: The anisotropic modelling of intensity distribution, affected by the construction of macroseismic planes, allows an analysis of the influence of each point of observed intensity on the analytical determination of epicenter and of the principal attenuation directions. Such a procedure is a vital aid in the cases in which the observed intensity points, that, for location or joined intensity level, are not consistent with an anisotropic model of intensity attenuation. A suitable filtering on intensity levels associated with the points of the intensity map, for a better modelling of observed intensity distribution, is proposed with the aim of a better seismic hazard evaluation
    Description: Published
    Description: 683-697
    Description: partially_open
    Keywords: Macroseismicity ; observed intensity filtering ; macroseismic planes ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
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  • 23
    Publication Date: 2017-04-04
    Description: Volcanic and geothermal areas are one of the major natural sources of H2S to the atmosphere. Its environmental impact is often the main cause of the opposition to the development of geothermal energy exploitation programs. In this paper we analyze the air concentrations and dispersion pattern of naturally emitted H2S at the geothermal area of Sousaki (Corinthia, Greece). Measurements, made with a network of passive samplers, evidence a rapid decrease of concentration values away from the emission points. The fact that the decrease is more pronounced in the summer with respect to the winter indicates that it is not only due to a dilution effect, but also to redox reactions favoured by higher temperatures and intense sunlight typical of the summer period.
    Description: Published
    Description: 1723-1728
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Hydrogen sulphide ; Environmental impact of volcanic activity ; Gas hazard ; Passive samplers ; 01. Atmosphere::01.01. Atmosphere::01.01.03. Pollution ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 24
    Publication Date: 2017-04-04
    Description: A revised Italian strong motion archive has become available since July 2007, including all the records of the strongest events occurred from 1972 to 2004. It contains the uncorrected and corrected accelerograms and the metadata relevant to seismic events, recording stations and instruments added after a careful revision. The availability of this archive allowed us to perform a first step towards an update of the reference ground motion prediction equations for Italy, which were evaluated by Sabetta and Pugliese in (Bull Seismol Soc Am 77:1491–1513, 1987), for peak ground acceleration and velocity, and subsequently extended to the 5% damped pseudovelocity response spectra in 1996. A subset with the 27 major earthquakes occurred in Italy from 1972 to 2002, in the magnitude range 4.6–6.9, was extracted and 235 good quality waveforms were selected, recorded at distances up to 183 km. The goodness of fit of the Sabetta and Pugliese (Bull Seismol Soc Am 86:337–352, 1996) model was explored using two independent statistical approaches (Spudich et al. Bull Seismol Soc Am 89:1156–1170, 1999 and Scherbaum et al. Bull Seismol Soc Am 94:2164– 2185, 2004). The results obtained show that the Sabetta and Pugliese (Bull Seismol Soc Am 77:1491–1513, 1987) does not adequately fit the new strong-motion data set, for its small standard deviation and its non-zero bias. In particular, the most noteworthy result is that the Sabetta and Pugliese (Bull Seismol Soc Am 77:1491–1513, 1987) over-predicts peak ground acceleration and velocity at rock sites. New coefficients for the prediction of horizontal peak ground acceleration, peak ground velocity and acceleration response spectra, adopting the same functional form in Sabetta and Pugliese (Bull Seismol Soc Am 77:1491–1513, 1987), were then evaluated in order to fit the new data set. This paper illustrates the steps made to update the existing ground motion prediction equations for Italy, discusses their limitations and provides the basis for future developments.
    Description: Published
    Description: 591–608
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: reserved
    Keywords: ground motion prediction ; equation ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
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  • 25
    Publication Date: 2017-04-04
    Description: The Italian Accelerometic Archive (ITACA) was created in 2007 during a joint project between the Italian Institute for Geophysics and Vulcanology (Istituto Nazionale di Geofisica e Vulcanologia, INGV) and the Italian Civil Protection (Dipartimento della Protezione Civile, DPC). The project, started in 2006, had the aim of filling the data gap of existing strong motion databases and facilitating strong motion data users in obtaining good quality waveforms, through the collection, homogenization and distribution of strong motion data acquired during the period 1972-2004 in Italy by different institutions (Ente Nazionale per l’Energia Elettrica, ENEL, Italian electricity company; Ente per le Nuove tecnologie, l’Energia e l’Ambiente, ENEA, Italian energy and environment organization DPC). The compiled database contains 2182 three-component waveforms generated by 1008 earthquakes with a maximum moment magnitude of 6.9 (1980 Irpinia earthquake) and can be accessed on-line at the portal denominated ITACA at the site http://itaca.mi.ingv.it, where a wide range of search tools enables the user to interactively retrieve events, recording stations and waveforms with particular characteristics, whose parameters can be specified, as needed, through user friendly interfaces. A range of display options allows users to view data in different contexts, extract and download time series and spectral data. This article describes the state of the art up to 2006 and the activities which led to the completion of the project.
    Description: In press
    Description: 5.2. TTC - Banche dati di sismologia strumentale
    Description: JCR Journal
    Description: open
    Keywords: strong-motion ; database ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
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  • 26
    Publication Date: 2017-04-04
    Description: A set of Ground Motion Prediction Equations (GMPEs) for the Italian territory is proposed, exploiting a new strong-motion data set become available since July 2007 through the Italian Accelerometric Archive (ITACA). The data set is composed by 561 three-component waveforms from 107 earthquakes with moment magnitude in the range 4.0–6.9, occurred in Italy from 1972 to 2007 and recorded by 206 stations at distances up to 100 km. The functional form used to derive GMPEs in Italy (Sabetta and Pugliese in Bull Seismol Soc Am 86(2):337–352, 1996) has been modified introducing a quadratic term for magnitude and a magnitude-dependent geometrical spreading. The coefficients for the prediction of horizontal and vertical peak ground acceleration, peak ground velocity and 5% damped acceleration response spectra are evaluated. This paper illustrates the new data set, the regression analysis and the comparisons with recently derived GMPEs in Europe and in the Next Generation Attenuation of Ground Motions (NGA) Project.
    Description: In press
    Description: 4.1. Metodologie sismologiche per l'ingegneria sismica
    Description: JCR Journal
    Description: open
    Keywords: ground motion ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion
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  • 27
    Publication Date: 2017-04-04
    Description: Large variations of the CO2 flux through the soil were observed between November 2002 and January 2006 at Mt. Etna volcano. In many cases, the CO2 flux was strongly influenced by changes in air temperature and atmospheric pressure. A new filtering method was then developed to remove the atmospheric influences on soil CO2 flux and, at the same time, to highlight the variations strictly related to volcanic activity. Successively, the CO2 corrected data were quantitatively compared with the spectral amplitude of the volcanic tremor by cross correlation function, cross-wavelet spectrum and wavelet coherence. These analyses suggested that the soil CO2 flux variations preceded those of volcanic tremor by about 50 days. Given that volcanic tremor is linked to the shallow (a few kilometer) magma dynamics and soil CO2 flux related to the deeper (*12 km b.s.l.) magma dynamics, the “delayed similarity” between the CO2 flux and the volcanic tremor amplitude was used to assess the average speed in the magma uprising into the crust, as about 170–260 m per day. Finally, the large amount of CO2 released before the onset of the 2004–2005 eruption indicated a deep ingression of new magma, which might have triggered such an eruption.
    Description: In press
    Description: N/A or not JCR
    Description: reserved
    Keywords: Mt. Etna ; Soil CO2 flux ; Volcanic tremor ; Cross-wavelet spectrum ; Wavelet coherence ; Cross correlation function ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 05. General::05.02. Data dissemination::05.02.02. Seismological data
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  • 28
    Publication Date: 2017-04-04
    Description: New Sr and Nd isotope data for whole rocks, glasses and minerals are combined to reconstruct the nature and origin of mixing end-members of the 200 km3 trachytic to phonolitic Campanian Ignimbrite (Campi Flegrei, Italy) magmatic system. The least-evolved magmatic end-member shows equilibrium between host glass and the majority of the phenocrysts and is less radiogenic in Sr and Nd than the most-evolved magma. On the contrary, only the Fe-rich pyroxene from the most-evolved erupted magma is in equilibrium with the matrix glass, while all other minerals are in isotopic disequilibrium. These magmas mixed prior to and during the Campanian Ignimbrite eruption and minerals were freely exchanged between the magma batches. Combining the results of the geochemical investigations on magma end-members with geophysical and geological data, we develop the following scenario. In stage 1, a parental, less differentiated magma rose into the middle crust, and evolved through combined crustal assimilation and crystal fractionation. In stage 2, the differentiated magma rose to shallower depth, fed the pre-Campanian Ignimbrite activity and evolved by further open-system processes into the most-evolved and most-radiogenic Campanian Ignimbrite end-member magma. In stage 3, new trachytic magma, isotopically distinct from the pre-Campanian Ignimbrite magmas, rose from ca. 6 km to shallower depth, recharged the most-evolved pre-Campanian Ignimbrite magma chamber, and formed the large and stratified Campanian Ignimbrite magmatic system. During the course of the Campanian Ignimbrite eruption, the two layers were tapped separately and/or simultaneously, and gave rise to the range of chemical and isotopic values displayed by the Campanian Ignimbrite pumices, glasses and minerals.
    Description: Published
    Description: 285-300
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: 3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
    Description: JCR Journal
    Description: reserved
    Keywords: Campanian Ignimbrite ; Radiogenic isotopes ; Mixing process ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 29
    Publication Date: 2017-04-04
    Description: This paper shows the results of a detailed reprocessing of aeromagnetic data,obtained by the downward projection to the seabed. The area of interest is centered over the Tyrrhenian Basin,whose bathymetric –topographic lay-out is characterized by a somewhat irregular trend.The origin of the intense depth variations depends on the Tyrrhenian structural setting,that is associated with the presence of several tectonic lineaments,seamounts or volcanic islands.The data were characterized by good quality and dense sam- pling,but they have been reprocessed in order either to solve some problems in the original compilation,and to reduce the distor- tion of the geomagnetic anomaly field caused by the difference of distance between the survey level and the magnetic source.The reprocessed magnetic map is proposed as an e ffective analysis tool for the Tyrrhenian area that is characterized by high susceptibility lithotypes.Downward projection of the aeromagnetic data by BTM algorithm increases the de finition of the anomalous magnetic signal without distortions in the geometric pattern of the field,thus showing a more stable and effective association between the magnetic anomalies and their geological sources.This effect is particularly true for high frequency anomalies that are directly comparable after the topographic projection because the depth filtering effect is attenuated.Moreover,the BTM method has been applied for the first time to a regional scale survey that shows substantial advantages because no fictitious anomalies in the high frequency sector of the spectrum were generated.This has been a typical effect of the traditional downward projection methods widely used before.The final result is a BTM anomaly map that is able to show the structural connections between the geological magnetic sources of the Tyrrhenian Sea area.
    Description: Published
    Description: 265-277
    Description: reserved
    Keywords: Potential methods,marine geomagnetism,downward continuation,Tyrrhenian Sea ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods
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  • 30
    Publication Date: 2017-04-04
    Description: National seismic risk maps are an important risk mitigation tool as they can be used for the prioritization of regions within a country where retrofitting of the building stock or other risk mitigation measures should take place. The production of a seismic risk map involves the convolution of seismic hazard data, vulnerability predictions for the building stock and exposure data. The seismic risk maps produced in Italy over the past 10 years are compared in this paper with recent proposals for seismic risk maps based on state-of-the-art seismic hazard data and mechanics-based vulnerability assessment procedures. The aim of the paper is to open the discussion for the way in which future seismic risk maps could be produced, making use of the most up-to-date information in the fields of seismic hazard evaluation and vulnerability assessment.
    Description: Italian Ministry of Research and Higher Education (MIUR—Ministero dell’Università e della Ricerca) through the financing of the project AIRPLANE (Advancing Interdisciplinary Research PLAtform on volcanoes aNd Earthquakes)
    Description: In press
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: JCR Journal
    Description: reserved
    Keywords: Seismic risk ; Seismic hazard ; 04. Solid Earth::04.06. Seismology::04.06.11. Seismic risk
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  • 31
    Publication Date: 2017-04-04
    Description: We show the magnetic model of the Selli-Vavilov region. The Selli Line is known as the northwestern edge of the southern Tyrrhenian basin. The tectonic evolution of the Tyrrhenian basin is dominated by a Tortonian - Quaternary extension through the eastward movement of the Apennine subduction system. This migration has generated a diffuse stretching of the continental crust with the emplacement of new oceanic material. This latter occurred in several localized zones where the eastward retreating of the Ionian subduction system produced a strong depletion of the crust with formation of basins and correlated spreading. Nowadays the presence of oceanic crust is confirmed through direct drilling investigation but a complete mapping of the oceanic crustal distribution is still lacking. The Selli-Vavilov region shows a differentiated crustal setting where seamount structures, the oceanic basement portions and continental crust blocks are superimposed. To this aim, a 2D inversion of the magnetic data of this region was conducted to define buried structures. The magnetic susceptibility pattern was computed by solving the least squares problem of the misfit between the predicted and real data for separated wavebands. This method produced two 2D models of the high and low frequency fields of the Selli-Vavilov region. The two apparent susceptibility maps provide different information for distinct ranges of depth. The results of the inversions were also combined with seismic data of the Selli region highlighting the position of the highly-magnetized buried bodies. The results confirm a role for the Selli Line as a deep crustal boundary dividing the Sardinian passive domain from the easternmost active region where different oceanic structures are located. The Selli Line has worked as a detachment fault system which has moved eastward. Finally, the Selli-Vavilov region may be interpreted as a tectonic result due to a passive asymmetrical rift occurred between the Tortonian and Pliocene.
    Description: Published
    Description: 251-266
    Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Description: 3.4. Geomagnetismo
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: JCR Journal
    Description: reserved
    Keywords: Geomagnetism ; Tectonics ; Geodynamics ; Inversion ; Oceanic crust ; Volcanic structure ; 04. Solid Earth::04.05. Geomagnetism::04.05.04. Magnetic anomalies ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 05. General::05.01. Computational geophysics::05.01.03. Inverse methods
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  • 32
    Publication Date: 2017-04-04
    Description: Cross-spectral analysis of ULF wave measurements recorded at ground magnetometer stations closely spaced in latitude allows accurate determinations of magnetospheric field line resonance (FLR) frequencies. This is a useful tool for remote sensing temporal and spatial variations of the magnetospheric plasma mass density. The spatial configuration of the South European GeoMagnetic Array (SEGMA, 1.56 〈 L 〈 1.89) offers the possibility to perform such studies at low latitudes allowing to monitor the dynamical coupling between the ionosphere and the inner plasmasphere. As an example of this capability we present the results of a cross-correlation analysis between FLR frequencies and solar EUV irradiance (as monitored by the 10.7-cm solar radio flux F10.7) suggesting that changes in the inner plasmasphere density follow the short-term (27-day) variations of the solar irradiance with a time delay of 1–2 days. As an additional example we present the results of a comparative analysis of FLR measurements, ionospheric vertical soundings and vertical TEC measurements during the development of a geomagnetic storm.
    Description: Published
    Description: 25-27
    Description: 1.6. Osservazioni di geomagnetismo
    Description: 1.7. Osservazioni di alta e media atmosfera
    Description: 3.9. Fisica della magnetosfera, ionosfera e meteorologia spaziale
    Description: JCR Journal
    Description: reserved
    Keywords: ULF waves ; Field line resonance ; Remote sensing ; Solar activity ; Plasmasphere ; Ionosphere ; 01. Atmosphere::01.02. Ionosphere::01.02.02. Dynamics ; 01. Atmosphere::01.02. Ionosphere::01.02.04. Plasma Physics ; 01. Atmosphere::01.03. Magnetosphere::01.03.03. Magnetospheric physics ; 05. General::05.07. Space and Planetary sciences::05.07.01. Solar-terrestrial interaction
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  • 33
    Publication Date: 2017-04-04
    Description: Following the 2001 and 2002–2003 flank eruptions, activity resumed at Mt. Etna on 7 September 2004 and lasted for about 6 months. This paper presents new petrographic, major and trace element, and Sr–Nd isotope data from sequential samples collected during the entire 2004–2005 eruption. The progressive change of lava composition allowed defining three phases that correspond to different processes controlling magma dynamics inside the central volcano conduits. The compositional variability of products erupted up to 24 September is well reproduced by a fractional crystallization model that involves magma already stored at shallow depth since the 2002–2003 eruption. The progressive mixing of this magma with a distinct new one rising within the central conduits is clearly revealed by the composition of the products erupted from 24 September to 15 October. After 15 October, the contribution from the new magma gradually becomes predominant, and the efficiency of the mixing process ensures the emission of homogeneous products up to the end of the eruption. Our results give insights into the complex conditions of magma storage and evolution in the shallow plumbing system of Mt. Etna during a flank eruption. Furthermore, they confirm that the 2004–2005 activity at Etna was triggered by regional movements of the eastern flank of the volcano. They caused the opening of a complex fracture zone extending ESE which drained a magma stored at shallow depth since the 2002–2003 eruption. This process favored the ascent of a different magma in the central conduits, which began to be erupted on 24 September without any significant change in eruptive style, deformation, and seismicity until the end of eruption.
    Description: Published
    Description: 781–793
    Description: 2.3. TTC - Laboratori di chimica e fisica delle rocce
    Description: JCR Journal
    Description: reserved
    Keywords: Geochemistry ; Isotopic compositions ; Magma feeding system ; Magma mixing ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
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  • 34
    Publication Date: 2022-05-25
    Description: © 2008 The Author. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Environmental Fluid Mechanics 8 (2008): 551-560, doi:10.1007/s10652-008-9076-5.
    Description: Experiments are reviewed in which a two-layer salt-stratified tank of water was mixed by turbulence. The density profile began as a single step and evolved to a smooth mixed profile. The turbulence was generated by many excursions of a horizontally moving vertical rod with Richardson number Ri 〉 0.9 and Reynolds Number Re 〉 600. There was almost perfect collapse of all the profiles to one universal profile as a function of a similarity variable. We develop a theoretical model for a simple mixing law with a buoyancy flux that is a function of internal Richardson number Rii. A similarity equation is found. A flux law that increases with small Rii and decreases with large Rii is considered next. Since no analytical solution is known, the similarity concept is tested by numerically integrating the equations in space and time. With buoyancy flux monotonically increasing with internal Richardson number, the similarity approach is valid for a profile starting from a slightly smoothed step. However, a shock forms for a mixing law with higher initial Rii (so that buoyancy flux decreases with Richardson number) and the similarity approach is invalid for those initial conditions.
    Keywords: Turbulence ; Mixing ; Stratified ; Similarity solution ; Layered fluid
    Repository Name: Woods Hole Open Access Server
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  • 35
    Publication Date: 2022-05-25
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Geo-Marine Letters 29 (2009): 395-404, doi:10.1007/s00367-009-0159-1.
    Description: A program of geophysical mapping and vibracoring was conducted to better understand the geologic evolution of Apalachicola Bay. Analyses of the geophysical data and sediment cores along with age control provided by 34 AMS 14C dates on marine shells and wood reveal the following history. As sea level rose in the early Holocene, fluvial deposits filled the Apalachicola River paleochannel, which extended southward under the central part of the bay and seaward across the continental shelf. Sediments to either side of the paleochannel contain abundant wood fragments, with dates documenting that those areas were forested at 8,000 14C years b.p. As sea level continued to rise, spits formed of headland prodelta deposits. Between ~6,400 and ~2,500 14C years b.p., an Apalachicola prodelta prograded and receded several times across the inner shelf that underlies the western part of the bay. An eastern deltaic lobe was active for a shorter time, between ~5,800 and 5,100 14C years b.p. Estuarine benthic foraminiferal assemblages occurred in the western bay as early as 6,400 14C years b.p., and indicate that there was some physical barrier to open-ocean circulation and shelf species established by that time. It is considered that shoals formed in the region of the present barrier islands as the rising sea flooded an interstream divide. Estuarine conditions were established very early in the post-glacial flooding of the bay.
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    Publication Date: 2022-05-25
    Description: © 2009 The Authors. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Marine Biology 156 (2009): 1049-1056, doi:10.1007/s00227-009-1149-6.
    Description: Behavioral observations using a remotely operated vehicle (ROV) in the Gulf of California in March, 2003, provided insights into the vertical distribution, feeding and anatomy of the rare and delicate ctenophore Thalassocalyce inconstans. Additional archived ROV video records from the Monterey Bay Aquarium Research Institute of 288 sightings of T. inconstans and 2,437 individual observations of euphausiids in the Gulf of California and Monterey Canyon between 1989 and 2005 were examined to determine ctenophore and euphausiid prey depth distributions with respect to temperature and dissolved oxygen concentration [dO]. In the Gulf of California most ctenophores (96.9%) were above 350 m, the top of the oxygen minimum layer. In Monterey Canyon the ctenophores were more widely distributed throughout the water column, including the hypoxic zone, to depths as great as 3,500 m. Computer-aided behavioral analysis of two video records of the capture of euphausiids by T. inconstans showed that the ctenophore contracted its bell almost instantly (0.5 s), transforming its flattened, hemispherical resting shape into a closed bi-lobed globe in which seawater and prey were engulfed. Euphausiids entrapped within the globe displayed a previously undescribed escape response for krill (‘probing behavior’), in which they hovered and gently probed the inner surfaces of the globe with antennae without stimulating further contraction by the ctenophore. Such rapid bell contraction could be effected only by a peripheral sphincter muscle even though the presence of circumferential ring musculature was unknown for the Phylum Ctenophora. Thereafter, several live T. inconstans were collected by hand off Barbados and microscopic observations confirmed that assumption.
    Description: Supported by the David and Lucile Packard Foundation and NOAA Grant #NA06OAR4600091.
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    Publication Date: 2022-05-25
    Description: © 2008 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Environmental Fluid Mechanics 8 (2008): 495-509, doi:10.1007/s10652-008-9107-2.
    Description: Estuarine turbulence is notable in that both the dissipation rate and the buoyancy frequency extend to much higher values than in other natural environments. The high dissipation rates lead to a distinct inertial subrange in the velocity and scalar spectra, which can be exploited for quantifying the turbulence quantities. However, high buoyancy frequencies lead to small Ozmidov scales, which require high sampling rates and small spatial aperture to resolve the turbulent fluxes. A set of observations in a highly stratified estuary demonstrate the effectiveness of a vessel-mounted turbulence array for resolving turbulent processes, and for relating the turbulence to the forcing by the Reynolds-averaged flow. The observations focus on the ebb, when most of the buoyancy flux occurs. Three stages of mixing are observed: (1) intermittent and localized but intense shear instability during the early ebb; (2) continuous and relatively homogeneous shear-induced mixing during the mid-ebb, and weakly stratified, boundary-layer mixing during the late ebb. The mixing efficiency as quantified by the flux Richardson number Rf was frequently observed to be higher than the canonical value of 0.15 from Osborn (J Phys Oceanogr 10:83–89, 1980). The high efficiency may be linked to the temporal–spatial evolution of shear instabilities.
    Description: The funding for this research was obtained from ONR Grant N00014-06-1-0292 and NSF Grant OCE-0729547.
    Keywords: Turbulence ; Estuaries ; Shear instability ; Buoyancy flux
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  • 38
    Publication Date: 2022-05-25
    Description: © 2009 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in JARO - Journal of the Association for Research in Otolaryngology 10 (2009): 497-509, doi:10.1007/s10162-009-0174-y.
    Description: The dynamic displacement of the semicircular canal cupula and modulation of afferent nerve discharge were measured simultaneously in response to physiological stimuli in vivo. The adaptation time constant(s) of normal cupulae in response to step stimuli averaged 36 s, corresponding to a mechanical lower corner frequency for sinusoidal stimuli of 0.0044 Hz. For stimuli equivalent to 40–200 deg/s of angular head velocity, the displacement gain of the central region of the cupula averaged 53 nm per deg/s. Afferents adapted more rapidly than the cupula, demonstrating the presence of a relaxation process that contributes significantly to the neural representation of angular head motions by the discharge patterns of canal afferent neurons. We also investigated changes in time constants of the cupula and afferents following detachment of the cupula at its apex—mechanical detachment that occurs in response to excessive transcupular endolymph pressure. Detached cupulae exhibited sharply reduced adaptation time constants (300 ms–3 s, n = 3) and can be explained by endolymph flowing rapidly over the apex of the cupula. Partially detached cupulae reattached and normal afferent discharge patterns were recovered 5–7 h following detachment. This regeneration process may have relevance to the recovery of semicircular canal function following head trauma.
    Description: Financial support was provided by the NIDCD R01 DC06685 (Rabbitt) and NASA GSRP 56000135 & NSF IGERT DGE- 9987616 (Breneman).
    Keywords: Vestibular ; Inner ear micromechanics ; Cupula regeneration ; Angular motion sensation ; Afferent response dynamics
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  • 39
    Publication Date: 2022-05-26
    Description: © 2009 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Coral Reefs 28 (2009): 327-337, doi:10.1007/s00338-009-0466-z.
    Description: Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population modelers need to track and assimilate evolving empirical results.
    Description: Work by CB Paris was supported by the National Science Foundation grant NSF-OCE 0550732. Work by M-A Coffroth and SR Thorrold was supported by the National Science Foundation grant NSF-OCE 0424688. Work by TL Shearer was supported by an International Cooperative Biodiversity Group grant R21 TW006662-01 from the Fogarty International Center at the National Institutes of Health.
    Keywords: Connectivity ; Larval dispersal ; Marine protected areas ; Resilience ; Replacement ; Genetics
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    In:  International Association of Geodesy Symposia
    Publication Date: 2020-02-12
    Description: The lAG International Symposium on Gravity, Geoid, and Space Missions 2004 (GGSM2004) was lield in the beautiful city of Porto, Portugal, from 30 August to 3 September 2004. This symposium encompassed the themes of Commission 2 (Gravity Field) of the newly structured lAG, as well as interdisciplinary topics related to geoid and gravity modeling, with special attention given to the current and planned gravi- dedicated satellite missions. The symposium also followed in the tradition of mid-term meetings that were held between the quadrennial joint meetings of the International Geoid and Gravity Commissions. The previous mid-term meetings were the International Symposia on Gravity, Geoid, and Marine Geodesy (Tokyo, 1996), and Gravity, Geoid, and Geodynamics (Banff, 2000). GGSM2004 aimed to bring together scientists from different areas in the geosciences, working with gravity and geoid related problems, both from the theoretical and practical points of view. Topics of interest included the integration of heterogeneous data and contributions from satellite and airborne techniques to the study of the spatial and temporal variations of the gravity field. In addition to the special focus on the CHAMP, GRACE, and GOCE satellite missions, attention was also directed toward projects addressing topographic and ice field mapping using SAR, LIDAR, and laser altimetry, as well as missions and studies related to planetary geodesy.
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    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
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  • 43
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    The European physical journal 43 (2005), S. 195-200 
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    Notes: Abstract. We have grown VOx thin films on different substrates in order to investigate the influence of epitaxial strain on the transport properties. We found that the electric conductivity is much larger for films grown under compressive strain on SrTiO3 substrates, as compared to bulk material and VOx films grown under tensile strain on MgO substrates. A clear crossover from metallic to semiconducting behavior is observed when increasing the oxygen content x. Apparently, the application of strain induces a Mott-Hubbard insulator-to-metal transition in VOx〈1. The VOx/SrTiO3 films show an unexpected large positive magnetoresistance effect at low temperatures, which is not found in the VOx films grown under tensile strain on MgO or on a substrate with a similar lattice parameter.
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    The European physical journal 43 (2005), S. 175-185 
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    Notes: Abstract. Using tight binding band picture for 2D graphite, and the Hubbard interaction, recently we obtained a gapless, neutral spin-1 collective mode branch in graphite [Phys. Rev. Lett. 89, 016402]. In this paper we present a detailed RPA analysis of the Neutron Scattering cross section for this collective mode. Near K-point and very close to Γ-point, the intensity of neutron scattering peaks vanishes as q3. This is shown using a simple Dirac cone model for the graphite band structure, which captures the small-q behavior of the system. As we move away from the Γ- and K-points in the Brillouin zone of the collective mode momenta, we can identify our collective mode quanta with spin triplet excitons with the spatial extent of the order of a few to a couple of lattice parameter a, with more or less anisotropic character, which differs from point to point. We also demonstrate that the inclusion of the long range tail of the Coulomb interaction in real graphite, does not affect our spin-1 collective mode qualitatively. This collective mode could be probed at different energy scales by thermal, hot and epithermal neutron scattering experiments. However, the smallness of the calculated scattering intensity, arising from a reduced form factor of carbon 2pz orbital makes the detection challenging.
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    Notes: Abstract. Systematic studies of AC susceptibility in a stoichiometric magnetite single crystal, in a series of low zinc doped magnetite (xZn 〈 0.04) and in nonstoichiometric magnetite samples (both single crystals and pellets) in the temperature range 4–300 K are presented. Measurements were performed in several AC fields ( $H_{AC}=0.2{-}20\ $ Oe) and at different frequencies (15–6000 Hz). It is suggested that the signal is primarily due to magnetic domain wall movement, strongly influenced by structural domains (twins). Two sets of anomalies were found: the first is associated with the Verwey transition and the second involves two different effects, one at 28 K, observed only in stoichiometric magnetite, and the other at 50 K. While the temperature position of the first anomaly (28 K) does not depend on frequency, the effect at 50 K is associated with an activation process, shifting to higher temperatures with increasing frequency. This last effect may be linked to the low temperature magnetoelectric effects terminating approximately at those temperatures. Qualitatively similar results have been observed by the Magnetic After Effect technique presented in the literature, that is associated with relaxation times that are 104 higher than those characteristic of our technique.
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    The European physical journal 43 (2005), S. 279-281 
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    Notes: Abstract. A method based on a selfconsistent solution of a quantum-mechanical system with temperature fluctuations described by Langevin equations is developed to calculate the charge carrier mobility in DNA. To model the charge transfer in DNA, a combined Holstein – SSH Hamiltonian is considered. As an example the hole mobility is calculated at room temperature for synthetic poly (G)/poly (C) duplex with regard to main structural fluctuations.
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    The European physical journal 43 (2005), S. 319-331 
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    Notes: Abstract. The three-band Emery model is reduced to a single-particle quantum model of Falicov-Kimball type, by allowing only up-spins to hop, and forbidding double occupation by projection. It is used to study the effects of geometric obstruction on mobile fermions in thermodynamic equilibrium. For low hopping overlap, there appears a plateau in the entropy, due to charge correlations, and related to real-space disorder. For large overlap, the equilibrium thermopower susceptibility remains anomalous, with a sign opposite to the one predicted from the single-particle density of states. The heat capacity and non-Fermi liquid response are discussed in the context of similar results in the literature. All results are obtained by evaluation of an effective single-particle free-energy operator in closed form. The method to obtain this operator is described in detail.
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    The European physical journal 43 (2005), S. 399-403 
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    Notes: Abstract. We have calculated the quantum conductance of single-walled carbon nanotube (SWNT) waveguide by using a tight binding-based Green’s function approach. Our calculations show that the slow conductance oscillations as well as the fast conductance oscillations are manifestations of the intrinsic quantum interference properties of the conducting SWNTs, being independent of the defect and disorder of the SWNTs. And zigzag type tubes do not show the slow oscillations. The SWNT electron waveguide is also found to have distinctly different transport behavior depending on whether or not the length of the tube is commensurate with a (3N+1) rule, with N the number of basic carbon repeat units along the nanotube length.
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    The European physical journal 43 (2005), S. 333-338 
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    Notes: Abstract. In multiferroic ferroelectromagnets, microscopic coupling interaction between the ferroelectric and magnetic order results in the macroscopic correlation between the dielectric and magnetic properties, which is defined as magnetodielectric effect. If we classify multiferroic ferroelectromagnets as two kinds: ferroelectric-ferromagnets and ferroelectric-antiferromagnets, we find the magnetodielectric behavior of these two kinds of ferroeletromagnets show obvious difference. We analyze the origin of the different magnetodielectric behavior and find that the fluctuation of the spin-pair correlation plays a critical role. Soft-mode theory based on DIFFOUR model and the mean-field theory are combined to deal with multiferroic ferroelectromagnetic system.
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    The European physical journal 38 (2005), S. 511-519 
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    Notes: Abstract. Taking as a starting point a Lorentz non-invariant abelian Higgs model defined in 1 + 3 dimensions, we carry out its dimensional reduction to D = 1 + 2, obtaining a new planar model composed by a Maxwell-Chern-Simons-Proca gauge sector, a massive scalar sector, and a mixing term (involving the fixed background $v^{\mu}$ ) that imposes the Lorentz violation to the reduced model. The propagators of the scalar and massive gauge field are evaluated and the corresponding dispersion relations determined. Based on the poles of the propagators, a causality and unitarity analysis is carried out at tree level. We then show that the model is totally causal, stable and unitary.
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    The European physical journal 38 (2005), S. 413-426 
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    Notes: Abstract. Hadronic events from the data collected with the DELPHI detector at LEP within the energy range from 89 Gev to 209 Gev are selected, their jet rates are determined and compared to predictions of four different event generators. One of them is the recently developed APACIC + + generator which performs a massive matrix element calculation matched to a parton shower followed by string fragmentation. The four-jet rate is used to measure $\alpha_s$ in the next-to-leading-order approximation yielding $${\alpha_s(M_Z^2)} = 0.1175 \pm 0.0030. $$ The running of $\alpha_s$ determined by using four-jet events has been tested. The logarithmic energy slope is measured to be $$ \frac{{\mathrm{d}}\alpha_s^{-1}}{{\mathrm{d}} \log E_{\mathrm {cm}}} = 1.14 \pm 0.36. $$ Since the analysis is based on four-jet final states it represents an alternative approach to previous DELPHI $\alpha_s$ measurements using event shape distributions.
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    The European physical journal 38 (2005), S. 447-459 
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    Notes: Abstract. Inclusive production cross sections are measured in deep inelastic scattering at HERA for meson states composed of a charm quark and a light antiquark or the charge conjugate. The measurements cover the kinematic region of photon virtuality 2 〈 Q 2 〈 100 Gev2, inelasticity 0.05 〈 y 〈 0.7, D meson transverse momenta $p_t(D) \ge 2.5$ Gev and pseudorapidity $\vert\eta(D)\vert \le 1.5$ . The identification of the D-meson decays and the reduction of the combinatorial background profit from the reconstruction of displaced secondary vertices by means of the H1 silicon vertex detector. The production of charmed mesons containing the light quarks u,d and s is found to be compatible with a description in which the hard scattering is followed by a factorisable and universal hadronisation process.
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    The European physical journal 38 (2005), S. 437-445 
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    Notes: Abstract. Results are presented on the photoproduction of isolated prompt photons, inclusively and associated with jets, in the $\gamma p$ center of mass energy range 142 〈 W 〈 266 GeV. The cross sections are measured for the transverse momentum range of the photons $5 〈 E_T^{\gamma} 〈 10$ GeV and for associated jets with E T jet 〉 4.5 GeV. They are measured differentially as a function of $E_T^{\gamma}, E_T^{\mathrm{jet}}$ , the pseudorapidities $\eta^{\gamma}$ and $\eta^{\mathrm{jet}}$ and estimators of the momentum fractions $x_{\gamma}$ and x p of the incident photon and proton carried by the constituents participating in the hard process. In order to further investigate the underlying dynamics, the angular correlation between the prompt photon and the jet in the transverse plane is studied. Predictions by perturbative QCD calculations in next to leading order are about $30\%$ below the inclusive prompt photon data after corrections for hadronisation and multiple interactions, but are in reasonable agreement with the results for prompt photons associated with jets. Comparisons with the predictions of the event generators PYTHIA and HERWIG are also presented.
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    The European physical journal 39 (2005), S. 109-121 
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    Notes: Abstract. A parameter-free statistical model is used to study multiplicity signatures for coherent production of charged pairs of parabosons of order p = 2 in comparison with those arising in the case of ordinary bosons, p = 1. Two non-negative real parameters arise because “ab” and “ba” are fundamentally distinct pair operators of charge “ + 1”, A-quanta and charge “-1”, B-quanta parabosons. In 3D plots of ${P_{m}}(q)\equiv$ “the probability of m paraboson charged pairs + q positive parabosons” versus $\langle n\rangle $ and $\langle n^2\rangle $ , the p = 1 curve is found to lie on the relatively narrow 2D p = 2 surface.
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    The European physical journal 39 (2005), S. 123-127 
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    Notes: Abstract. In this paper, the canonical quantization of singular Lagrangian defined in a finite volume is discussed by studying a 1 + 1 dimensional free Schrödinger field. We take the boundary conditions (BCs) as Dirac constraints, and show that those BCs as well as the intrinsic constraints (which are introduced by the singularities of Lagrangian) form the second class constraints. The quantization is performed canonically.
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    The European physical journal 39 (2005), S. 101-107 
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    Notes: Abstract. Some 3-3-1 models predict the existence of a non-perturbative regime at the TeV scale. We study in these models and their supersymmetric extensions, the energy at which the non-perturbative limit and a Landau-like pole arise. An order of magnitude for the mass of the extra neutral vector boson, $Z^\prime$ , present in these models is also obtained.
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    The European physical journal 39 (2005), S. 229-243 
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    Notes: Abstract. We consider the collider phenomenology of split-supersymmetry models. Despite the challenging nature of the signals in these models the long-lived gluino can be discovered with masses above 2 TeV at the LHC. At a future linear collider we will be able to observe the renormalization group effects from split supersymmetry, using measurements of the neutralino and chargino masses and cross sections.
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    The European physical journal 39 (2005), S. 249-252 
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    Notes: Abstract. We consider gauge theories based on abelian p-forms on real compact hyperbolic spaces. Using the zeta-function regularization method and the trace tensor kernel formula, we determine explicitly an expression for the vacuum energy (Casimir energy) corresponding to skew-symmetric tensor fields. It is shown that the topological component of the Casimir energy for co-exact forms on even-dimensional spaces, associated with the trivial character, is always negative. We infer on the possible cosmological consequences of this result.
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    The European physical journal 39 (2005), S. 185-193 
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    Notes: Abstract. Lattice motivated triplet color scalar field theory is analyzed. We consider non-minimal as well as covariant derivative coupling with SU(2) gauge fields. Field configurations generated by external electric sources are presented. Moreover non-Abelian magnetic monopoles are found. Dependence on the spatial coordinates in the obtained solutions is identical as in the usual Abelian case. We show also that after a decomposition of the fields a modified Faddeev-Niemi action can be obtained. It contains explicit O(3) symmetry breaking term parameterized by the condensate of an isoscalar field. Due to that Goldstone bosons observed in the original Faddeev-Niemi model are removed.
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    The European physical journal 39 (2005), S. 1-39 
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    Notes: Abstract. We present a simple empirical parameterization of the x- and t-dependence of generalized parton distributions at zero skewness, using forward parton distributions as input. A fit to experimental data for the Dirac, Pauli and axial form factors of the nucleon allows us to discuss quantitatively the interplay between longitudinal and transverse partonic degrees of freedom in the nucleon (“nucleon tomography”). In particular we obtain the transverse distribution of valence quarks at given momentum fraction x. We calculate various moments of the distributions, including the form factors that appear in the handbag approximation to wide-angle Compton scattering. This allows us to estimate the minimal momentum transfer required for reliable predictions in that approach to be around $\vert t\vert \simeq 3 {\rm GeV}^2$ . We also evaluate the valence contributions to the energy-momentum form factors entering Ji’s sum rule.
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    The European physical journal 39 (2005), S. 55-59 
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    Notes: Abstract. The electron structure functions are studied in polarized e + e - scattering. The formulae for longitudinally and transversely polarized electrons are presented. The smallness of the electron mass leads to negligible cross-sections and asymmetries in some cases. Positivity constraints on the structure functions and parton densities are constructed and discussed. The cross-section asymmetries at very high energies, where the inclusion of all elecroweak bosons is necessary, are calculated. Numerical examples, using the asymptotic solutions for the parton densities inside the electron, are presented.
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    The European physical journal 39 (2005), S. 61-69 
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    Notes: Abstract. We compute the pole mass of the gluon in QCD from the local composite operator formalism at two loops in the $\overline{{\rm MS}}$ renormalization scheme. For the Yang-Mills theory an estimate of the mass at two loops is $2.13\Lambda_{\overline{{\rm MS}}}$ .
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    The European physical journal 39 (2005), S. 155-161 
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    Notes: Abstract. We perform a global parton analysis of deep inelastic and related hard-scattering data, including ${{\mathcal{O}}}(\alpha_{\rm QED})$ corrections to the parton evolution. Although the quality of the fit is essentially unchanged, there are two important physical consequences. First, the different DGLAP evolution of u and d type quarks introduces isospin violation, i.e. $u^p \neq d^n$ , which is found to be unambiguously in the direction to reduce the NuTeV $\sin^2\theta_W$ anomaly. A second consequence is the appearance of photon parton distributions $\gamma(x,Q^2)$ of the proton and the neutron. In principle these can be measured at HERA via the deep inelastic scattering processes $e N \to e\gamma X$ ; our predictions are in agreement with the present data.
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    The European physical journal 39 (2005), S. 483-497 
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    Notes: Abstract. It has been proposed to abandon the requirement that parallel transporters in gauge theories are unitary (or pseudo-orthogonal). This leads to a geometric interpretation of Vierbein fields as parts of gauge fields, and non-unitary parallel transport in extra directions yields Higgs fields. In such theories, the holonomy group H is larger than the gauge group G. Here we study a one-dimensional model with fermions which retains only the extra dimension, and which is soluble in the sense that its renormalization group flow may be exactly computed, with G = SU(2) and non-compact $H\subseteq GL(2,\mathbf{C})$ , or G = U(2), H = GL(2,C). In all cases the asymptotic behavior of the Higgs potential is computed, and with one possible exception for G = SU(2), H = GL(2,C), there is a flow of the action from a UV fixed point which describes a SU(2)-gauge theory with unitary parallel transporters, to a IR fixed point. We explain how exponential mass ratios of fermions of different flavor can arise through spontaneous symmetry breaking, within the general framework.
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    The European physical journal 39 (2005), S. 511-518 
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    Notes: Abstract. The Bethe ansatz equations for the spin 1/2 Heisenberg XXZ spin chain are numerically solved, and the energy eigenvalues are determined for the antiferromagnetic case. We examine the relation between the XXZ spin chain and the massless Thirring model, and show that the spectrum of the XXZ spin chain has a gapless excitation while the regularized Thirring model calculated with the Bogoliubov transformation method has a finite gap. This finite gap spectrum is also confirmed by the Bethe ansatz solution of the massless Thirring model.
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    The European physical journal 39 (2005), S. 411-420 
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    Notes: Abstract. Muon pair production through the radiative return is of importance for a measurement of the hadronic production cross section in two ways: it provides an independent calibration and it may give rise to an important background for the measurement of the pion form factor. With this motivation the Monte Carlo event generator PHOKHARA is extended to include next-to-leading order radiative corrections to the reaction $e^ + e^-\to \mu^ + \mu^-\gamma$ . Furthermore, virtual ISR corrections to FSR from pions are introduced, which extends the applicability of the generator into a new kinematical regime. Finally, the effect of photon vacuum polarization is introduced into this new version of the generator.
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    The European physical journal 40 (2005), S. 275-286 
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    Notes: Abstract. The computation of the radiation flux related to the Hawking temperature of a Schwarzschild black hole or another geometric background is still well-known to be fraught with a number of delicate problems. In spherical reduction, as shown by one of the present authors (Kummer) with Vassilevich, the correct black body radiation follows when two “basic components” (conformal anomaly and a “dilaton” anomaly) are used as input in the integrated energy-momentum conservation equation. The main new element in the present work is the use of a quite different method, the covariant perturbation theory of Barvinsky and Vilkovisky, to establish directly the full effective action which determines these basic components. In the derivation of Kummer and Vassilevich the computation of the dilaton anomaly implied one potentially doubtful intermediate step which can be avoided here. Moreover, the present approach also is sensitive to IR (renormalization) effects. We realize that the effective action naturally leads to expectation values in the Boulware vacuum which, making use of the conservation equation, suffice for the computation of the Hawking flux in other quantum states, in particular for the relevant Unruh state. Thus, a rather comprehensive discussion of the effects of (UV and IR) renormalization upon radiation flux and energy density is possible.
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    The European physical journal 40 (2005), S. 157-164 
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    Notes: Abstract. The correlator of vector heavy-quark currents at small q 2 is considered in the large- $\beta_0$ limit. The leading IR renormalon ambiguity of the sum of the perturbative series is canceled by the UV renormalon ambiguity of the gluon condensate. The asymptotic behavior of the perturbative series is obtained in a model-independent way, up to a single unknown normalization factor. Gluon-virtuality distribution functions for the perturbative correction are calculated.
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    The European physical journal 40 (2005), S. 243-250 
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    Notes: Abstract. The new data on k t distributions obtained at RHIC are analyzed by means of selected models of statistical and stochastic origin in order to estimate their importance in providing new information on the hadronization process, in particular on the value of the temperature at freeze-out to the hadronic phase.
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    The European physical journal 40 (2005), S. 193-197 
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    Notes: Abstract. We propose a constituent quark model to evaluate heavy decay constants and form factors relevant for $ B \to D^{(*)}$ semileptonic transitions. We show that the model reproduces the scaling laws dictated by the spin-flavor symmetry in the heavy quark limit and describes quite well the experimental data.
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    The European physical journal 40 (2005), S. 199-203 
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    Notes: Abstract. We discuss the difference between n-dimensional regularization and n-dimensional reduction for processes in QCD which have an additional mass scale. Examples are heavy flavor production in hadron-hadron collisions or on-shell photon-hadron collisions where the scale is represented by the mass m. Another example is electroproduction of heavy flavors where we have two mass scales given by m and the virtuality of the photon $\smash[b]{Q = \sqrt{-q^2}}$ . Finally we study the Drell-Yan process where the additional scale is represented by the virtuality $\smash[t]{Q = \sqrt{q^2}}$ of the vector boson ( $\gamma^*, W, Z$ ). The difference between the two schemes is not accounted for by the usual oversubtractions. There are extra counter terms which multiply the mass scale dependent parts of the Born cross sections. In the case of the Drell-Yan process it turns out that the off-shell mass regularization agrees with n-dimensional regularization.
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    The European physical journal 40 (2005), S. 367-382 
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    Notes: Abstract. We evaluate the size of isospin breaking corrections to form factors f and g of the $K_{\ell 4}$ decay process $K^ + \rightarrow\pi^ + \pi^-\ell^ + \nu_{\ell}$ which is actually measured by the extended NA48 setup at CERN. We found that, keeping apart the effect of Coulomb interaction, isospin breaking does not affect the moduli. This is due to the cancellation between corrections of electromagnetic origin and those generated by the difference between up and down quark masses. On the other hand, electromagnetism affects considerably the phases if the infrared divergence is dropped out using a minimal subtraction scheme. Consequently, the greatest care must be taken in the extraction of $\pi\pi$ phase shifts from experiment.
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  • 73
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    Notes: Abstract. The charge asymmetry of the g, h, and k Dalitz plot parameters for ${K^{\pm}\rightarrow \pi^{\pm} \pi^{0} \pi^{0}}$ decays has been measured with 35 GeV/c hadron beams at the 70 GeV IHEP accelerator. The g, h, and k values obtained appear to be identical for $K^{\pm}$ decays within the errors quoted. In particular, the charge asymmetry A g = (g + – g -)/(g + + g -) of the slope g is equal to ${(0.2 \pm 1.9)\cdot 10^{-3}}$ .
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    The European physical journal 40 (2005), S. 395-417 
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    Notes: Abstract. We prove the collinear factorization theorem for the process $\pi\gamma^*\to\pi$ at the twist-3 level in the covariant gauge by means of the Ward identity, concentrating on the two-parton case. It is shown that soft divergences cancel and collinear divergences are grouped into the pseudo-scalar and pseudo-tensor two-parton twist-3 pion distribution amplitudes. The delicate summation of a complete set of diagrams for achieving factorization in momentum, spin, and color spaces is emphasized. The proof is then extended to the exclusive semileptonic decay $B\to\pi l\nu$ , assuming the hard scale to be of $O\smash{\bigl(\sqrt{\bar{\Lambda} M_B}\bigr)}$ , where $\bar{\Lambda}$ is a hadronic scale and M B the B meson mass. We explain the distinction between the factorization of collinear divergences for a pion distribution amplitude and of soft divergences for a B meson distribution amplitude. The gauge invariance and universality of the two-parton twist-3 pion distribution amplitudes are confirmed. The proof presented here can accommodate the leading twist-2 case. We then compare our proof with that performed in the framework of soft-collinear effective theory.
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    The European physical journal 40 (2005), S. 555-564 
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    Notes: Abstract. For large masses, the two heavy neutral Higgs bosons are nearly degenerate in many 2-Higgs doublet models, and particularly in supersymmetric models. In such a scenario the mixing between the states can be very large if the theory is CP-noninvariant. We analyze the formalism describing this configuration, and we point to some interesting experimental consequences.
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  • 76
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    Notes: Abstract. We have studied neutron quantum states in the potential well formed by the earth’s gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in the two lowest quantum states correspond to expectations with an experimental accuracy. A position-sensitive neutron detector with an extra-high spatial resolution of $\sim 2 \mathrm{\mu} $ m was developed and tested for this particular experiment, to be used to measure the spatial density distribution in a standing neutron wave above a mirror for a set of some of the lowest quantum states. The present experiment can be used to set an upper limit for an additional short-range fundamental force. We studied methodological uncertainties as well as the feasibility of improving further the accuracy of this experiment.
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    The European physical journal 40 (2005), S. 383-394 
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    Notes: Abstract. We complete here our work on isospin violation in the $K \to 3 \pi$ system. We first calculate $K\to2\pi$ to the same order as we did $K \to 3 \pi$ in papers I and II of this series. This adds the effects of order G 27 p 2 (m u -m d ) and G 27 p 2 e 2 to earlier work. We calculate also the lowest order bremsstrahlung contributions, $K\to2\pi\gamma,3\pi\gamma$ . With these and our earlier results we perform a full fit to all available CP-conserving data in the $K\to2\pi,3\pi$ system including isospin violation effects. We perform these fits under various input assumptions as well as test the factorization and the vector dominance model for the weak NLO low energy constants.
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    The European physical journal 40 (2005), S. 333-341 
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    Notes: Abstract. Data collected at LEP at centre-of-mass energies $\sqrt{s} = 189-209$ GeV are used to study correlations of the spin of W bosons using $\mathrm{e}^ + \mathrm{e}^-\to \mathrm{W}^ + \mathrm{W}^-\to {\ensuremath{\ell\nu\mathrm{q\bar{q}}}}$ events. Spin correlations are favoured by data, and found to agree with the Standard Model predictions. In addition, correlations between the W-boson decay planes are studied in $\mathrm{e}^ + \mathrm{e}^-{}\to{}\mathrm{W}^ + \mathrm{W}^- \to{}{\ensuremath{\ell\nu\mathrm{q\bar{q}}}}$ and $\mathrm{e}^ + \mathrm{e}^-{}\to{}\mathrm{W}^ + \mathrm{W}^-{}\to{}{\ensuremath{\text{q}\bar{\text{q}}\text{q}\bar{\text{q}}}}{}$ events. Decay-plane correlations are measured to be consistent with the Standard Model predictions.
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  • 79
    ISSN: 1434-601X
    Keywords: 23.40.-s Beta decay; double beta decay; electron and muon capture ; 13.30.-a Decays of baryons ; 12.15.Hh Determination of Kobayashi-Maskawa matrix elements
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    Notes: Abstract. The apparatus described here, aSPECT, will be used for a measurement of the neutrino-electron angular correlation coefficient a in the decay of free neutrons. The idea of the aSPECT spectrometer is to measure the integrated proton energy spectrum very accurately using an energy filter by electrostatic retardation and magnetic adiabatic collimation. The main ideas of the spectrometer are presented, followed by an explanation of the adiabatic transmission function. Details of the superconducting coil and of the electrode system are given, as well as a discussion of the most important systematic effects: magnetic field and electrostatic potential inhomogeneities, deviation from adiabatic motion, scattering in the residual gas, background, Doppler effect, edge effect, and detector efficiency. Using this spectrometer, the parameter a is planned to be measured with an absolute experimental uncertainty of δa ≈ 3 . 10-4, from which the axial vector to vector coupling constant ratio λ can be determined with an accuracy of δλ ≈ 0.001.
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  • 80
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    Keywords: 11.10.Ef Lagrangian and Hamiltonian approach ; 13.75.Gx Pion-baryon interactions ; 36.10.-k Exotic atoms and molecules (containing mesons, muons, and other unusual particles) ; 26.65.+t Solar neutrinos
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    Notes: Abstract. Within the Nuclear Nambu-Jona-Lasinio model of light nuclei (the NNJL model), describing strong low-energy nuclear interactions, we compute the width of the energy level of the ground state of pionic deuterium. The theoretical value fits well the experimental data. Using the cross-sections for the reactions νe + d → p + p + e- and νe + d → p + n + νe, computed in the NNJL model, and the experimental values of the events of these reactions, detected by the SNO Collaboration, we compute the boron neutrino fluxes. The theoretical values agree well with the experimental data and the theoretical predictions within the Standard Solar Model by Bahcall. We argue the applicability of the constraints on the astrophysical factor for the solar proton burning, imposed by helioseismology, to the width of the energy level of the ground state of pionic deuterium. We show that the experimental data on the width satisfy these constraints. This testifies an indirect measurement of the recommended value of the astrophysical factor for the solar proton burning in terrestrial laboratories in terms of the width of the energy level of the ground state of pionic deuterium.
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    The European physical journal 43 (2005), S. 11-18 
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    Notes: Abstract. We study (inverse) photoemission from systems with strong coupling of doped carriers to phonons. Using an adiabatic approximation, we develop a method for calculating spectra. This method is particularly simple for systems where the electron-phonon coupling can be neglected in the initial state, e.g., the undoped t-J model. The theory then naturally explains why the electron-phonon coupling just leads to a broadening of spectra calculated without electron-phonon coupling, without changing the dispersion. This is in agreement with recent angle-resolved photoemission spectroscopy (ARPES) on undoped cuprates, and it supports the interpretation in terms of strong electron-phonon interaction. The theory also shows that for systems with strong electron-phonon coupling in the initial state, the result cannot in general be related to the spectrum obtained without electron-phonon coupling.
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    The European physical journal 43 (2005), S. 29-37 
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    Notes: Abstract. We extracted, from strongly-correlated ab-initio calculations, a complete model for the chain subsystem of the Sr0.4Ca13.6Cu24O41 incommensurate compound. A second neighbor t-J+V model has been determined as a function of the fourth crystallographic parameter τ, for both low and room temperature crystallographic structures. The analysis of the obtained model shows the crucial importance of the structural modulations on the electronic structure through the on-site energies and the magnetic interactions. The structural distortions are characterized by their long range effect on the cited parameters that hinder the reliability of analyses such as BVS. One of the most striking results is the existence of antiferromagnetic nearest-neighbor interactions for metal-ligand-metal angles of 90○. A detailed analysis of the electron localization and spin arrangement is presented as a function of the chain to ladder hole transfer and of the temperature. The obtained spin arrangement is in agreement with antiferromagnetic correlations in the chain direction at low temperature.
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    The European physical journal 43 (2005), S. 65-71 
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    Notes: Abstract. Here we address a fundamental issue in surface physics: the dynamics of adsorbed molecules. We study this problem when the particle’s desorption is characterized by a non Markovian process, while the particle’s adsorption and its motion in the bulk are governed by a Markovian dynamics. We study the diffusion of particles in a semi-infinite cubic lattice, and focus on the effective diffusion process at the interface z = 1. We calculate analytically the conditional probability to find the particle on the z=1 plane as well as the surface dispersion as functions of time. The comparison of these results with Monte Carlo simulations show an excellent agreement.
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    The European physical journal 43 (2005), S. 81-92 
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    Notes: Abstract. The electrical and optical properties of ordered passive arrays, constituted of inductive and capacitive components, are usually deduced from Kirchhoff’s rules. Under the assumption of periodic boundary conditions, comparable results may be obtained via an approach employing transfer matrices. In particular, resonances in the dielectric spectrum are demonstrated to occur if all eigenvalues of the transfer matrix of the entire array are unity. The latter condition, which is shown to be equivalent to the habitual definition of a resonance in impedance for an array between electrodes, allows for a convenient and accurate determination of the resonance frequencies, and may thus be used as a tool for the design of materials with a specific dielectric response. For the opposite case of linear arrays in a large network, where periodic boundary condition do not apply, several asymptotic properties are derived. Throughout the article, the derived analytic results are compared to numerical models, based on either Exact Numerical Renormalisation or the spectral method.
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    The European physical journal 43 (2005), S. 283-294 
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    Notes: Abstract. We investigate the process of ripple formation in a viscous fluid when a sand bed is submitted to a laminar shear flow. We propose a new description for the sand transport which takes into account the fact that the transport rate does not adapt instantaneously to a change of the fluid velocity due to grain inertia. It introduces a new length, called here after equilibrium length leq, corresponding to the distance needed for a immobile grain to equilibrate its velocity with that of the fluid. The transport rate is therefore found to depend not only on the fluid shear stress and bed slope (as usually assumed) but also on grain inertia. Within the framework of this model we analyzed the mechanisms of the sand bed instability. It is found that the instability results from the competition between the destabilizing effect of fluid inertia and the stabilizing ones of grain inertia and bed slope. We derive analytical scaling laws for the most amplified wavelength, its growth rate and phase velocity. We found in particular that at small particle Reynolds number Rep, the most amplified wavelength scales as the viscous length lν defined as $\sqrt{\nu/\gamma}$ (where γ is the shear rate and ν the fluid viscosity) and at large Rep it scales as the equilibrium length leq. Our results are compared with available experimental data.
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    The European physical journal 43 (2005), S. 251-269 
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    Notes: Abstract. The problem on finding the coefficients of the Landau free energy expansion into the power series of parameter of order has been considered for solutions and melts of linear heteropolymers whose molecules comprise several types monomeric units arranged stochastically. The presence of such a quenched structural disorder places this problem outside the framework of the traditional statistical physics inviting for its solution special approaches. One of them, based on the replica concept and actively engaged in theoretical physics of disordered systems, has been invoked in this paper to derive expressions for the vertex functions in the Landau theory of heteropolymer liquids. An algorithm has been formulated which permits one resorting to the simple diagram technique to write down expressions for these functions of any order in terms of the statistical characteristics of chemical quenched structure of polymer molecules. Explicit expressions for the contributions to the Landau free energy up to the fourth degree of order parameters for polymer systems with an arbitrary structural disorder have been presented to illustrate this general algorithm. Its potentialities have been also exemplified for the melt of random m-component copolymer where exact analytical formulas for these contributions up to n=6 at an arbitrary m have been derived for the first time.
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    The European physical journal 43 (2005), S. 163-174 
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    Notes: Abstract. We have studied the magnetic structure of the orthorhombic compound Ho2Ni2Pb by means of neutron diffraction in zero field and in magnetic fields up to 4.5 T. Both powder and single-crystalline samples were used. Previous bulk measurements suggest two distinct magnetic phase transitions: one at TN = 7.0 K and the other at 4.8 K. Our neutron diffraction measurements, which were made in the range 1.5-20 K, showed that Ho2Ni2Pb has a collinear magnetic structure with unequal number of up and down Ho moments that are aligned parallel and antiparallel to the c axis. At the lowest temperatures the Ho moments are equal in size, each 8.3 μB in agreement with magnetization data. The magnetic structure can be described as having a 5a ×b ×c magnetic unit cell. Below Ts = 3.0 K the structure is squared up. A smooth development of all the magnetic moment magnitudes indicates that the magnetic structure remains in principle the same over the whole temperature range, the “phase transition” around 4.8 K can be identified as an inflection point in the temperature dependence of one of the Ho moments. With increasing temperature there is a clear development towards a simple transverse sine-wave modulated magnetic structure that is established just below TN.
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    The European physical journal 43 (2005), S. 221-242 
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    Notes: Abstract. We present a systematic study of moment evolution in multidimensional stochastic difference systems, focusing on characterizing systems whose low-order moments diverge in the neighborhood of a stable fixed point. We consider systems with a simple, dominant eigenvalue and stationary, white noise. When the noise is small, we obtain general expressions for the approximate asymptotic distribution and moment Lyapunov exponents. In the case of larger noise, the second moment is calculated using a different approach, which gives an exact result for some types of noise. We analyze the dependence of the moments on the system’s dimension, relevant system properties, the form of the noise, and the magnitude of the noise. We determine a critical value for noise strength, as a function of the unperturbed system’s convergence rate, above which the second moment diverges and large fluctuations are likely. Analytical results are validated by numerical simulations. Finally, we present a short discussion of the extension of our results to the continuous time limit.
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    The European physical journal 43 (2005), S. 243-250 
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    Notes: Abstract. We analyze the phenomenon of frequency clustering in a system of coupled phase oscillators. The oscillators, which in the absence of coupling have uniformly distributed natural frequencies, are coupled through a small-world network, built according to the Watts-Strogatz model. We study the time evolution and determine variations in the transient times depending on the disorder of the network and on the coupling strength. We investigate the effects of fluctuations in the average frequencies, and discuss the definition of the threshold for synchronization. We characterize the structure of clusters and the distribution of cluster sizes in the synchronization transition, and define suitable order parameters to describe the aggregation of the oscillators as the network disorder and the coupling strength change. The non-monotonic behavior observed in some order parameters is related to fluctuations in the mean frequencies.
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    The European physical journal 43 (2005), S. 405-419 
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    Notes: Abstract. We investigate clean cylindrical nanostructures with an applied longitudinal static magnetic field. The ground state of these systems becomes degenerate for particular values of the field due to Aharonov-Bohm effect. The Coulomb interaction introduces couplings between the electronic configurations. Consequently, depending on particular selection rules, the ground state may become, in the interacting case, a many body state at the degeneracy points: a gap is then opened. To study this problem, we propose a variational multireference wave function which goes beyond the Hartree-Fock approximation. Using this ansatz, in addition to the replacements of some crossings by avoided crossings, two other important effects of the electron-electron interaction are pointed out: (i) the long-range part of the Coulomb potential tends to shift the position in magnetic field of the crossing or avoided crossing points and, (ii) at the points of degeneracy or near degeneracy, the interaction can drive the system from a singlet to a triplet state inducing new real crossing points in the ground state energy curve as function of the field. In any case, the crossing points that are due to either orbital or spin effects, should manifest themselves in various experiments as sudden changes in the response of the system (magnetoconductance, magnetopolarisability, ...) when the magnetic field is tuned.
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    The European physical journal 43 (2005), S. 339-345 
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    Notes: Abstract. Polaron properties are studied in bulk wurtzite nitride ternary mixed crystals AxB1-xN (A, B = Al, Ga, In) with the use of a dielectric continuum Fröhlich-like electron-phonon interaction Hamiltonian. The polaronic self-trapping energy and effective mass are analytically derived by taking the mixing properties of the LO and TO polarizations due to the anisotropy effect into account in the mono-phonon approximation. The numerical computation has been performed for the wurtzite ternary mixed crystal materials InxGa1-xN, AlxGa1-xN, and AlxIn1-xN as functions of the composition x. The results show that the polaronic self-trapping energies in the wurtzite structures are bigger than that in zinc-blende structures for the materials calculated. It is also found that the structure anisotropy increases the electron-phonon interaction in wurtizte nitride semiconductors. The results indicate that the LO-like phonon influence on the polaronic self-trapping energy and effective mass is dominant, and the anisotropy effect is obvious.
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    The European physical journal 43 (2005), S. 363-368 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A generalization of the pure site and pure bond percolation problems in which pairs of nearest neighbor sites (site dimers) and linear pairs of nearest neighbor bonds (bond dimers) are independently occupied at random on a square lattice is studied. We called this model as dimer site-bond percolation. Motivated by considerations of cluster connectivity, we have used two distinct schemes (denoted as $S\cap B$ and $S\cup B$ ) for dimer site-bond percolation. In $S \cap B$ ( $S \cup B$ ), two points are said to be connected if a sequence of occupied sites and (or) bonds joins them. By using finite-size scaling theory, data from $S \cap B$ and $S \cup B$ are analyzed in order to determine i) the phase boundary between the percolating and non-percolating regions and ii) the numerical values of the critical exponents of the phase transition occurring in the system. The results obtained are discussed in comparison with the corresponding ones for classical monomer site-bond percolation.
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  • 93
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    The European physical journal 43 (2005), S. 373-378 
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We present a semi-analytic study of Ising spins on a simple square or cubic lattice coupled to a transverse magnetic field of variable strength. The formal analysis employs correlated basis functions (CBF) theory to investigate the properties of the corresponding N-body ground and excited states. For these states we discuss two different ansaetze of correlated trial wave functions and associated longitudinal and transverse excitation modes. The formalism is then generalized to describe the spin system at nonzero temperatures with the help of a suitable functional approximating the Helmholtz free energy. To test the quality of the functional in a first step we perform numerical calculations within the extended formalism but ignore spatial correlations. Numerical results are reported on the energies of the longitudinal and the transverse excitation modes at zero temperature, on critical data at finite temperatures, and on the optimized spontaneous magnetization as a function of temperature and external field strength.
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  • 94
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    The European physical journal 38 (2005), S. 395-411 
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The production of single- and multi-photon events has been studied in the reaction $e^ + e^-\rightarrow\gamma(\gamma) + invisible \quad particles$ . The data collected with the DELPHI detector during the years 1999 and 2000 at centre-of-mass energies between 191 GeV and 209 GeV was combined with earlier data to search for phenomena beyond the Standard Model. The measured number of light neutrino families was consistent with three and the absence of an excess of events beyond that predicted by the Standard Model processes was used to set limits on new physics. Both model-independent searches and searches for new processes predicted by supersymmetric and extra-dimensional models have been made. Limits on new non-standard model interactions between neutrinos and electrons were also determined.
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  • 95
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    The European physical journal 38 (2005), S. 495-510 
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We present a systematic study of 400 combinations of the charged lepton and neutrino mass matrices with six vanishing entries or texture zeros. Only 24 of them, which can be classified into a few distinct categories, are found to be compatible with current neutrino oscillation data at the $3\sigma$ level. A peculiar feature of the lepton mass matrices in each category is that they have the same phenomenological consequences. Taking account of a simple seesaw scenario for six parallel patterns of the charged lepton and Dirac neutrino mass matrices with six zeros, we show that it is possible to fit the experimental data at or below the $2\sigma$ level. In particular, the maximal atmospheric neutrino mixing can be reconciled with a strong neutrino mass hierarchy in the seesaw case. Numerical predictions are also obtained for the neutrino mass spectrum, flavor mixing angles, CP-violating phases and effective masses of the tritium beta decay and the neutrinoless double beta decay.
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  • 96
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    The European physical journal 38 (2005), S. 461-474 
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. Parton energy loss effects in heavy-ion collisions are studied with the Monte Carlo program PQM (Parton Quenching Model) constructed using the BDMPS quenching weights and a realistic collision geometry. The merit of the approach is that it contains only one free parameter that is tuned to the high-p t nuclear modification factor measured in central Au-Au collisions at $\sqrt{s_{\rm NN}} = 200$ GeV. Once tuned, the model is consistently applied to all the high-p t observables at 200 GeV: the centrality evolution of the nuclear modification factor, the suppression of the away-side jet-like correlations, and the azimuthal anisotropies for these observables. Predictions for the leading-particle suppression at nucleon-nucleon centre-of-mass energies of 62.4 and 5500 GeV are presented. The limits of the eikonal approximation in the BDMPS approach, when applied to finite-energy partons, are discussed.
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  • 97
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    The European physical journal 39 (2005), S. 71-86 
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The recent observations of f 0(980) in charmless B decays motivate further studies of scalar particle and glueball production in these processes. Amplitudes for charmless two-body B decays involving the members of the scalar nonet are presented based on the symmetries of the dominant penguin contribution. Different scenarios for the lightest scalar nonet are investigated in view of the presently available data. We describe the evidence from B decays for f 0(1500) with a flavor octet like mixing and the hints towards the members of the $q\bar{q}$ nonet of lowest mass. There is further support for the hypothesis of a broad 0 + + glueball acting as coherent background especially in $B\to K\overline K K$ . The estimated B decay rates into gluonic mesons represent a sizable fraction of the theoretically derived decay rate for ${b\to sg}$ .
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  • 98
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    The European physical journal 38 (2005), S. 483-494 
    ISSN: 1434-6052
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    Topics: Physics
    Notes: Abstract. The non-linear chiral quark-meson U(3) x U(3) model is solved using the Tamm-Dancoff inspired approximation which is described in an earlier paper [Phys. Rev. D 58, 034003 (1998)]. The resulting system of 15 coupled non-linear differential equations self-consistently determines all quark-meson coupling constants. Also the obtained solutions for quark and meson fields are stable and physically acceptable. As the zeroth approximation of a more refined structure they were used to calculate SU(3) baryon octet magnetic moments and axial coupling constants with baryon state vectors containing valence quarks only, at this primordial level. The results are very promising, so possibilities to pursuit more sophistication and improved physical input is indicated.
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  • 99
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    The European physical journal 38 (2005), S. 475-482 
    ISSN: 1434-6052
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    Topics: Physics
    Notes: Abstract. We compute the cross section for exclusive double-diffractive $\gamma \gamma$ production at the Tevatron, $p{\bar{p}} \to p + \gamma \gamma + {\bar{p}}$ , and the LHC. We evaluate both the gg and $q\bar{q}\;\; t$ -channel exchange contributions to the process. The observation of exclusive $\gamma \gamma$ production at the Tevatron will provide a check on the model predictions and offer an opportunity to confirm the expectations for exclusive double-diffractive Higgs production at the LHC.
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  • 100
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    The European physical journal 38 (2005), S. 521-526 
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We investigate the one-parameter family of transformations on superfields of the super principal chiral model and obtain different zero-curvature representations of the model. The parametric transformation is related to the super Riccati equations and an infinite set of local and non-local conservation laws is derived. A Lax representation of the model is presented which gives rise to a superspace monodromy operator.
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