540 research outputs found
Universality of Brunnian (-body Borromean) four and five-body systems
We compute binding energies and root mean square radii for weakly bound
systems of and identical bosons. Ground and first excited states of
an -body system appear below the threshold for binding the system with
particles. Their root mean square radii approach constants in the limit of weak
binding. Their probability distributions are on average located in
non-classical regions of space which result in universal structures. Radii
decrease with increasing particle number. The ground states for more than five
particles are probably non-universal whereas excited states may be universal
Picture-Hanging Puzzles
We show how to hang a picture by wrapping rope around n nails, making a
polynomial number of twists, such that the picture falls whenever any k out of
the n nails get removed, and the picture remains hanging when fewer than k
nails get removed. This construction makes for some fun mathematical magic
performances. More generally, we characterize the possible Boolean functions
characterizing when the picture falls in terms of which nails get removed as
all monotone Boolean functions. This construction requires an exponential
number of twists in the worst case, but exponential complexity is almost always
necessary for general functions.Comment: 18 pages, 8 figures, 11 puzzles. Journal version of FUN 2012 pape
The Q^2-Dependence of Nuclear Transparency for Exclusive Production
Exclusive coherent and incoherent electroproduction of the meson
from H and N targets has been studied at the HERMES experiment as a
function of coherence length (), corresponding to the lifetime of hadronic
fluctuations of the virtual photon, and squared four-momentum of the virtual
photon (). The ratio of N to H cross sections per nucleon,
known as nuclear transparency, was found to increase (decrease) with increasing
coherence length for coherent (incoherent) electroproduction. For
fixed coherence length, a rise of nuclear transparency with is observed
for both coherent and incoherent production, which is in agreement
with theoretical calculations of color transparency.Comment: 5 pages, 4 figure
Evidence for Quark-Hadron Duality in the Proton Spin Asymmetry
Spin-dependent lepton-nucleon scattering data have been used to investigate
the validity of the concept of quark-hadron duality for the spin asymmetry
. Longitudinally polarised positrons were scattered off a longitudinally
polarised hydrogen target for values of between 1.2 and 12 GeV and
values of between 1 and 4 GeV. The average double-spin asymmetry in
the nucleon resonance region is found to agree with that measured in
deep-inelastic scattering at the same values of the Bjorken scaling variable
. This finding implies that the description of in terms of quark
degrees of freedom is valid also in the nucleon resonance region for values of
above 1.6 GeV.Comment: 5 pages, 1 eps figure, table added, new references added, in print in
Phys. Rev. Let
The -dependence of the generalised Gerasimov-Drell-Hearn integral for the deuteron, proton and neutron
The Gerasimov-Drell-Hearn (GDH) sum rule connects the anomalous contribution
to the magnetic moment of the target nucleus with an energy-weighted integral
of the difference of the helicity-dependent photoabsorption cross sections. The
data collected by HERMES with a deuterium target are presented together with a
re-analysis of previous measurements on the proton. This provides a measurement
of the generalised GDH integral covering simultaneously the nucleon-resonance
and the deep inelastic scattering regions. The contribution of the
nucleon-resonance region is seen to decrease rapidly with increasing . The
DIS contribution is sizeable over the full measured range, even down to the
lowest measured . As expected, at higher the data are found to be in
agreement with previous measurements of the first moment of . From data on
the deuteron and proton, the GDH integral for the neutron has been derived and
the proton--neutron difference evaluated. This difference is found to satisfy
the fundamental Bjorken sum rule at GeV.Comment: 12 pages, 10 figure
Single-spin Azimuthal Asymmetries in Electroproduction of Neutral Pions in Semi-inclusive Deep-inelastic Scattering
A single-spin asymmetry in the azimuthal distribution of neutral pions
relative to the lepton scattering plane has been measured for the first time in
deep-inelastic scattering of positrons off longitudinally polarized protons.
The analysing power in the sin(phi) moment of the cross section is 0.019 +/-
0.007(stat.) +/- 0.003(syst.). This result is compared to single-spin
asymmetries for charged pion production measured in the same kinematic range.
The pi^0 asymmetry is of the same size as the pi^+ asymmetry and shows a
similar dependence on the relevant kinematic variables. The asymmetry is
described by a phenomenological calculation based on a fragmentation function
that represents sensitivity to the transverse polarization of the struck quark.Comment: 4 pages, 1 figure, replaced to correct eprint author field, 2nd
replacement to correct figure; upper limit of model predictions are
corrected. No correction to data or conclusion
Mental health research priorities for Europe
Mental and brain disorders represent the greatest health burden to Europe—not only for directly affected individuals, but also for their caregivers and the wider society. They incur substantial economic costs through direct (and indirect) health-care and welfare spending, and via productivity losses, all of which substantially affect European development. Funding for research to mitigate these effects lags far behind the cost of mental and brain disorders to society. Here, we describe a comprehensive, coordinated mental health research agenda for Europe and worldwide. This agenda was based on systematic reviews of published work and consensus decision making by multidisciplinary scientific experts and affected stakeholders (more than 1000 in total): individuals with mental health problems and their families, health-care workers, policy makers, and funders. We generated six priorities that will, over the next 5–10 years, help to close the biggest gaps in mental health research in Europe, and in turn overcome the substantial challenges caused by mental disorders
Investigating the influence of product perception and geometric features
Research in emotional design and Kansei Engineering has shown that aesthetics play a significant role in the appeal of a product. This paper contributes to establishing a methodology to identify the relationships between perceptions, aesthetic features, desire to own and background of consumers. Surveys were conducted with 71 participants to gather their perceptions of 11 vase concepts. Advanced statistical analyses, including mixed models, were applied to allow generalisation of the results beyond the data sample. Significant relations between the desire to own a product and how the product is perceived were found (the desire to own was found to be related to beautiful, expensive, elegant, exciting, feminine, common and dynamic vases), as well as between the perceptions and the parameters describing the form of the vases (a vase was perceived as beautiful if it had many curved lines and was simple and tall). An automated mixed model analysis was conducted and revealed that general rules can be found between aesthetic features, perceptions and ownership, which can apply across gender and culture. The findings include design rules that link aesthetic features with perceptions. These contribute to research as guidelines for design synthesis and can either be implemented via shape grammars or parametric modelling approaches. These rules are also interesting for 3D printing applications, especially important when the consumer is the designer. Some of these design rules are linked to the desire to own a product, they have implications for industry, and they offer guidelines to creating attractive products that people want to own
Caribou, Petroleum, and the Limits of Locality in the Canada–US Borderlands
his article discusses Karsten Heuer’s 2006 book Being Caribou in light of debates in ecocriticism and border studies about how to define the local in the context of environmental problems of vast range and uncertain temporality. It explores how Heuer’s book about following the Porcupine Caribou herd’s migration engages in multiple forms of boundary crossing—between countries, between hemispheric locations, and between species—and shows how insights from Indigenous storytelling complicate the book’s appeal to environmentalist readers by asserting a prior, transnational Indigenous presence in the transboundary landscapes of present-day Alaska and the Yukon
Metadherin Mediates Lipopolysaccharide-Induced Migration and Invasion of Breast Cancer Cells
BACKGROUND: Breast cancer is the most prevalent cancer in women worldwide and metastatic breast cancer has very poor prognosis. Inflammation has been implicated in migration and metastasis of breast cancer, although the exact molecular mechanism remains elusive. PRINCIPAL FINDINGS: We show that the pro-inflammatory endotoxin Lipopolysaccharide (LPS) upregulates the expression of Metadherin (MTDH), a recently identified oncogene, in a number of breast cancer lines. Stable knockdown of MTDH by shRNA in human breast MDA-MB-231 cells abolishes LPS-induced cell migration and invasion as determined by several in vitro assays. In addition, knockdown of MTDH diminishes Nuclear Factor-kappa B (NF-κB) activation by LPS and inhibited LPS-induced IL-8 and MMP-9 production. CONCLUSIONS: These results strongly suggest that MTDH is a pivotal molecule in inflammation-mediated tumor metastasis. Since NF-κB, IL-8 and MMP-9 play roles in LPS-induced invasion or metastasis, the mechanism of MTDH-promoted invasion and metastasis may be through the activation of NF-κB, IL-8 and MMP-9, also suggesting a role of MTDH in regulating both inflammatory responses and inflammation-associated tumor invasion. These findings indicate that MTDH is involved in inflammation-induced tumor progression, and support that MTDH targeting therapy may hold promising prospects in treating breast cancer
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