1,127 research outputs found
Characterization of radially symmetric finite time blowup in multidimensional aggregation equations,
This paper studies the transport of a mass in by a
flow field . We focus on kernels for
for which the smooth densities are known to develop
singularities in finite time. For this range This paper studies the transport
of a mass in by a flow field . We
focus on kernels for for which the
smooth densities are known to develop singularities in finite time. For this
range we prove the existence for all time of radially symmetric measure
solutions that are monotone decreasing as a function of the radius, thus
allowing for continuation of the solution past the blowup time. The monotone
constraint on the data is consistent with the typical blowup profiles observed
in recent numerical studies of these singularities. We prove monotonicity is
preserved for all time, even after blowup, in contrast to the case
where radially symmetric solutions are known to lose monotonicity. In the case
of the Newtonian potential (), under the assumption of radial
symmetry the equation can be transformed into the inviscid Burgers equation on
a half line. This enables us to prove preservation of monotonicity using the
classical theory of conservation laws. In the case and at
the critical exponent we exhibit initial data in for which the
solution immediately develops a Dirac mass singularity. This extends recent
work on the local ill-posedness of solutions at the critical exponent.Comment: 30 page
Shock Dynamics in Particle-Laden Thin Films
PRL 94(11) March 25, 2005 117803We present theory and experiments for thin film particle-laden flow on an incline. At higher particle concentration and inclination angle, a new phenomenon is observed in which a large particle-rich ridge forms at the contact line. We derive a lubrication theory for this system which is qualitatively compared to preliminary experimental data. The ridge formation arises from the creation of two shocks due to the differential transport rates of fluid and particles. This parallels recent findings of double shocks in thermal-gravity driven flow [A. L. Bertozzi et. al., PRL, 81, 5169 (1998), J. Sur et. al., PRL 90, 126105 (2003), A. M¨unch, PRL 91, 016105 (2003)]. However, here the emergence of the shocks arises from a new mechanism involving the settling rates of the species.NS
Italian Law 326/2003 for The Reimbursement of Orphan and Life Saving Drugs Awaiting Market Entry: Approvals, Rejections And Methods In Aifa's Evaluation Process Between January 2013 And May 2015
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Achieving the WHO/UNAIDS antiretroviral treatment 3 by 5 goal: what will it cost?
The "3 by 5" goal to have 3 million people in low and middle income countries on antiretroviral therapy (ART) by the end of 2005 is ambitious. Estimates of the necessary resources are needed to facilitate resource mobilisation and rapid channelling of funds to where they are required. We estimated the financial costs needed to implement treatment protocols, by use of country-specific estimates for 34 countries that account for 90% of the need for ART in resource-poor settings. We first estimated the number of people needing ART and supporting programmes for each country. We then estimated the cost per patient for each programme by country to derive total costs. We estimate that between US5.1 billion dollars and US5.9 billion dollars will be needed by the end of 2005 to provide ART, support programmes, and cover country-level administrative and logistic costs for 3 by 5
Synthesis, Characterization, and Theory of [9]-, [12]-, and [18]Cycloparaphenylene: Carbon Nanohoop Structures
The first synthesis and characterization of [9]-, [12]-, and [18]cycloparaphenylene was demonstrated utilizing a novel aromatization reaction. We refer to these fascinating structures as "carbon nanohoops" due to their structural similarity to carbon nanotubes. Additionally, we have utilized computational methods to understand the unique properties of these fully conjugated macrocycles
Responsible Research and Innovation in Science Education: the IRRESISTIBLE Project
The EU funded IRRESISTIBLE-project (Project Coordinator: Jan Apotheker, University of Groningen, Netherlands) develop activities designed to foster the involvement of high school and elementary students and the public in Responsible Research and Innovation (RRI). In the project, awareness about RRI is raised in two ways: increasing content knowledge about research by bringing topics of cutting edge research into the program; fostering a discussion among the students on RRI issues about the topics that are introduced. Responsible Research and Innovation focuses on six key issues: Engagement, Gender equality, Science education, Ethics, including societal relevance and acceptability of research and innovation outcomes , Open access, Governance. The project combines formal and informal teaching to familiarize schoolchildren with science. Sixteen partners in ten countries are involved and coordinated by Science LinX. Each participants will establish a community of learners (CoL). The communities include school teachers together with university experts in the field of science communication and science centre staff. Each CoL will develop materials that the teachers will use at their own schools and students will develop an exhibit for a science centre in their own country.
Once they have completed their teaching module, the teachers will each train five colleagues, in using the developed modules from the first year. Ultimately, this project will train almost ten thousand pupils to consider the social impact of scientific research
Copper Phosphoramidite Catalyzed Enantioselective Ring-Opening of Oxabicyclic Alkenes: Remarkable Reversal of Stereocontrol
Hadrons in the Nuclear Medium
Quantum Chromodynamics, the microscopic theory of strong interactions, has
not yet been applied to the calculation of nuclear wave functions. However, it
certainly provokes a number of specific questions and suggests the existence of
novel phenomena in nuclear physics which are not part of the the traditional
framework of the meson-nucleon description of nuclei. Many of these phenomena
are related to high nuclear densities and the role of color in nucleonic
interactions. Quantum fluctuations in the spatial separation between nucleons
may lead to local high density configurations of cold nuclear matter in nuclei,
up to four times larger than typical nuclear densities. We argue here that
experiments utilizing the higher energies available upon completion of the
Jefferson Laboratory energy upgrade will be able to probe the quark-gluon
structure of such high density configurations and therefore elucidate the
fundamental nature of nuclear matter. We review three key experimental
programs: quasi-elastic electro-disintegration of light nuclei, deep inelastic
scattering from nuclei at , and the measurement of tagged structure
functions. These interrelated programs are all aimed at the exploration of the
quark structure of high density nuclear configurations.
The study of the QCD dynamics of elementary hard processes is another
important research direction and nuclei provide a unique avenue to explore
these dynamics. We argue that the use of nuclear targets and large values of
momentum transfer at would allow us to determine whether the physics of the
nucleon form factors is dominated by spatially small configurations of three
quarks.Comment: 52 pages IOP style LaTex file and 20 eps figure
Beam-Target Double-Spin Asymmetry A(LT) in Charged Pion Production from Deep Inelastic Scattering on a Transversely Polarized He-3 Target at 1.4 \u3c Q(2) \u3c 2.7 GeV2
We report the first measurement of the double-spin asymmetry A(LT) for charged pion electroproduction in semi-inclusive deep-inelastic electron scattering on a transversely polarized He-3 target. The kinematics focused on the valence quark region, 0.16 \u3c x \u3c 0.35 with 1.4 \u3c Q(2) \u3c 2.7 GeV2. The corresponding neutron A(LT) asymmetries were extracted from the measured He-3 asymmetries and proton over He-3 cross section ratios using the effective polarization approximation. These new data probe the transverse momentum dependent parton distribution function g(1T)(q) and therefore provide access to quark spin-orbit correlations. Our results indicate a positive azimuthal asymmetry for pi(-) production on He-3 and the neutron, while our pi(+) asymmetries are consistent with zero
Depinning of three-dimensional drops from wettability defects
Substrate defects crucially influence the onset of sliding drop motion under
lateral driving. A finite force is necessary to overcome the pinning influence
even of microscale heterogeneities. The depinning dynamics of three-dimensional
drops is studied for hydrophilic and hydrophobic wettability defects using a
long-wave evolution equation for the film thickness profile. It is found that
the nature of the depinning transition explains the experimentally observed
stick-slip motion.Comment: 6 pages, 9 figures, submitted to ep
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