1,557 research outputs found
An Integro-Differential Conservation Law arising in a Model of Granular Flow
We study a scalar integro-differential conservation law. The equation was
first derived in [2] as the slow erosion limit of granular flow. Considering a
set of more general erosion functions, we study the initial boundary value
problem for which one can not adapt the standard theory of conservation laws.
We construct approximate solutions with a fractional step method, by
recomputing the integral term at each time step. A-priori L^\infty bounds and
BV estimates yield convergence and global existence of BV solutions.
Furthermore, we present a well-posedness analysis, showing that the solutions
are stable in L^1 with respect to the initial data
Idiopathic thrombocytopenic purpura: current concepts in pathophysiology and management.
Idiopathic thrombocytopenic purpura (ITP) is characterized by
a low platelet count, which is the result of both increased pla-
telet destruction and insufficient platelet production. Although
the development of autoantibodies against platelet glycoproteins remains central in the pathophysiology of ITP, several abnormalities involving the cellular mechanisms of immune modu-
lation have been identified. Conventional treatments for ITP aim
at reducing platelet destruction, either by immunosuppression or splenectomy. Two new thrombopoietic agents,AMG 531 and eltrombopag, have been used in clinical trials to stimulate platelet production in ITP patients not responsive to standard
treatments. These new molecules bear no structural resemblance to thrombopoietin, but still bind and activate the thrombopoietin receptor. This review will focus on the pathophysiology and treatment of ITP in adults, highlighting recent advances
in both fields
The boundary Riemann solver coming from the real vanishing viscosity approximation
We study a family of initial boundary value problems associated to mixed
hyperbolic-parabolic systems:
v^{\epsilon} _t + A (v^{\epsilon}, \epsilon v^{\epsilon}_x ) v^{\epsilon}_x =
\epsilon B (v^{\epsilon} ) v^{\epsilon}_{xx}
The conservative case is, in particular, included in the previous
formulation.
We suppose that the solutions to these problems converge to a
unique limit. Also, it is assumed smallness of the total variation and other
technical hypotheses and it is provided a complete characterization of the
limit.
The most interesting points are the following two.
First, the boundary characteristic case is considered, i.e. one eigenvalue of
can be .
Second, we take into account the possibility that is not invertible. To
deal with this case, we take as hypotheses conditions that were introduced by
Kawashima and Shizuta relying on physically meaningful examples. We also
introduce a new condition of block linear degeneracy. We prove that, if it is
not satisfied, then pathological behaviours may occur.Comment: 84 pages, 6 figures. Text changes in Sections 1 and 3.2.3. Added
Section 3.1.2. Minor changes in other section
Trade Statistics of the Zollverein, 1834-1871
The purpose of this paper is to highlight the fact that the lack of useable German trade statistics for the period preceding the German political unifica- tion is not a fatality. The documents published during the Zollverein period by the Central Bureau of the Zollverein, the Statistische Uebersichten über Waaren- Verkehr und Zoll-Ertrag im Deutschen Zoll-Vereine für das Jahr..., do not provide prices nor trade flows in value nor any indication of countries of ultimate origin and destination. To overcome these imperfections, a great number of estimates of Zollverein trade statistics have been published since 1842 but they are ques- tionable as well. Nevertheless, the good quality of Statistische Übersichten’s quantity data should make possible the reconstruction of consistent series of German trade, total, by product and in value, over the period 1834-1871
Invasive and non-invasive analyses for knowledge and conservation of Roman wall paintings of the Villa of the Papyri in Herculaneum
none7noThe Villa of the Papyri is one of the most imposing architectural examples of Herculaneum dated before the eruption occurred on 79 A.D. During the earliest years of the excavation of the site (18th century), the Villa has been explored through a thick network of tunnels dug into the hard bank of tuff rock. Recent excavations went on discontinuously between 1990s and 2008, until the discovery of a room located in the lower floor of the build- ing, showing serious phenomena of colour change of some areas of the painted walls. Some dark green parts of mural paintings after volcanic mud removal became white and powdered, detaching from the plaster.
During the last restoration works a scientific approach became necessary in order to acquire detailed information about the wall painting technique and the degradation phenomena occurring in some decorative elements in the vault of the Basis Villa (a room in the lower floor of the building); it was established to perform a scientific recognition.
Integrated investigations – carried out by optical microscopy, scanning electron microscopy with X-ray microanalysis (EDS), X-ray diffractometry (XRD), ion chromatography (IC), FT-IR spectroscopy, gas chromatog- raphy mass spectrometry (GC-MS) – had primarily the goal to characterize the materials used for the realization of the these impressive wall paintings, as well as to assess their state of conservation.
A second aim of the research was to test the reliability of non-invasive analyses that are sometimes performed in situ to study mural paintings, like reflectance spectrometry in the visible range (vis-RS), X-ray fluorescence (ED-XRF) and micro-Raman spectroscopy, as well as imaging analyses like false colour IR (IRC) and visible induced IR luminescence (VIL).
The whole set of analyses allowed to identify a typical Vitruvian plaster with the following pigments: Egyptian blue, red and yellow ochre, goethite and hematite particles, green earth and carbon black particles.
The high content of soluble salts, which is related to the sulphur-rich water in the site located few metres above water level in the walls and floors, caused a worsening in the state of conservation of mural paintings.openM. L. Amadori; P. Baraldi; S. Barcelli; G. Poldi; F. Ferrucci; A. Andreotti; M.P. ColombiniAmadori, MARIA LETIZIA; P., Baraldi; S., Barcelli; G., Poldi; Ferrucci, Fabiano; A., Andreotti; M. P., Colombin
New Insight on Medieval Painting in Sicily: The Virgin Hodegetria Panel in Monreale Cathedral (Palermo, Italy)
: The Virgin Hodegetria, located in the Cathedral of Santa Maria Nuova in Monreale, near
Palermo (Italy), probably dating the first half of the 13th century, is one of the earliest examples
of medieval panel painting in Sicily. A diagnostic campaign was carried out on the panel aiming
to identify the constituting materials and the executive technique, as well as to assess the state of
conservation for supporting the methodological choice of the restoration intervention. Both non invasive (X-ray radiography, digital microscope, multispectral imaging, ED-X-ray fluorescence) and
micro-invasive (polarised light microscopy, ESEM-EDX, ATR-FTIR spectroscopy and micro-Raman
spectroscopy) analyses were performed. According to the results, the executive technique followed
the 13th–14th-century Italian painting tradition. A complex structure was applied on the wooden
support, consisting of a double layer of canvas and several ground layers of gypsum and glue based binder. The underdrawing was made by a brush using carbonaceous black pigment. The
original palette includes red ochre, red lead, azurite, carbon black and bone black. During the several
restorations, mercury-based red, indigo, smalt blue, orpiment and synthetic mars were used. The
original silver leaf of the frame was covered with red tin-based lake and subsequently regilded with
gold leaf. Proteinaceous and oil binders were also detecte
Cross-species infectivity of H3N8 influenza virus in an experimental infection in swine
Avian influenza A viruses have gained increasing attention due to their ability to cross the species barrier and cause severe disease
in humans and other mammal species as pigs. H3 and particularly H3N8 viruses, are highly adaptive since they are found in
multiple avian and mammal hosts. H3N8 viruses have not been isolated yet from humans; however, a recent report showed that
equine influenza A viruses (IAVs) can be isolated from pigs, although an established infection has not been observed thus far in
this host. To gain insight into the possibility of H3N8 avian IAVs to cross the species barrier into pigs, in vitro experiments and
an experimental infection in pigs with four H3N8 viruses from different origins (equine, canine, avian, and seal) were performed.
As a positive control, an H3N2 swine influenza virus A was used. Although equine and canine viruses hardly replicated
in the respiratory systems of pigs, avian and seal viruses replicated substantially and caused detectable lesions in inoculated pigs
without previous adaptation. Interestingly, antibodies against hemagglutinin could not be detected after infection by hemagglutination
inhibition (HAI) test with avian and seal viruses. This phenomenon was observed not only in pigs but also in mice immunized
with the same virus strains. Our data indicated that H3N8 IAVs from wild aquatic birds have the potential to cross the
species barrier and establish successful infections in pigs that might spread unnoticed using the HAI test as diagnostic tool.We thank Jaime Maldonado and HIPRA (Spain) for the A/Swine/Spain/
54008/2004 (H3N2) strain, Edward J. Dubovi and Cornell University for
the A/Canine/NY/105447/08 (H3N8) IAV strain, T. M. Chambers and the
University of Kentucky for the A/Equine/OH/1/03 (H3N8) IAV strain,
and Hon Ip and the U.S. Geological Survey National Wildlife Health
Center for the A/American black duck/Maine/44411-532/2008 (H3N8)
and the A/Harbor Seal/New Hampshire/179629/2011 (H3N8) IAV
strains. We thank Sergio López, David Solanes, Francisco X. Abad, Jordi
Alberola, Jaume Martorell, and Eduard J. Cunilleras for help in providing
different samples and during the experimental infections, as well as the
personnel in Cat3 laboratories and the animal house. We thank Adolfo
García-Sastre for providing materials and for support as the principal
investigator of the NIAID-funded Center for Research in Influenza Pathogenesis
(HHSN266200700010C).
The research leading to these results received funding from the European
Community’s Seventh Framework Programme (FP7, 2007-2013),
the Research Infrastructures Action under grant FP7-228393 (a NADIR
project), and projects AGL2010-22200-C02-01 and AGL2007-60274 of
the Spanish Ministry of Science and Innovation
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