4,277 research outputs found
Flood impact assessment under climate change scenarios in central Taipei area, Taiwan
Providing effective information regarding flood control for responding climate change is essential to
future flood risk management for cities. This study simulated and assessed the impacts of flooding for
future climate change scenarios in Taipei city, Taiwan. We modelled rainfall events, generated by
general circulation models, with different return periods. The flood extents and damage in the Central
Taipei Area for the A1B climate change scenarios were compared to the ones, caused by the rainfall
events with same return periods, without climate change (baseline scenario). The proposed approach
provides potential flooding maps and flood damage assessment for climate change scenarios as
useful information for flood risk management in urban areas.The work is supported by the National Science Council, Taiwan (NSC 99-2915-I-002-120) and the
CORFU project, funded by the European Commission through Framework Programme 7, Grant
Number 244047
Single Gene Deletions of Orexin, Leptin, Neuropeptide Y, and Ghrelin Do Not Appreciably Alter Food Anticipatory Activity in Mice
Timing activity to match resource availability is a widely conserved ability in nature. Scheduled feeding of a limited amount of food induces increased activity prior to feeding time in animals as diverse as fish and rodents. Typically, food anticipatory activity (FAA) involves temporally restricting unlimited food access (RF) to several
hours in the middle of the light cycle, which is a time of day when rodents are not normally active. We compared this model to calorie restriction (CR), giving the mice 60% of their normal daily calorie intake at the same time each day. Measurement of body temperature and home cage behaviors suggests that the RF and CR models are very similar but CR has the advantage of a clearly defined food intake and more stable mean body temperature. Using the CR model, we then attempted to verify the published result that orexin deletion diminishes food anticipatory activity (FAA) but observed little to no diminution in the response to CR and, surprisingly, that orexin KO mice are refractory to body weight loss on a CR diet. Next we tested the orexigenic neuropeptide Y (NPY) and ghrelin and the anorexigenic hormone, leptin, using mouse mutants. NPY deletion did not alter the behavior or physiological response to CR. Leptin deletion impaired FAA in terms of some activity measures, such as walking and rearing, but did not substantially diminish hanging behavior preceding feeding time, suggesting that leptin knockout mice do anticipate daily meal time but do not manifest the full spectrum of activities that typify FAA. Ghrelin knockout mice do not have impaired FAA on a CR diet. Collectively, these results suggest that the individual hormones and neuropepetides tested do not regulate FAA by acting individually but this does not rule out the possibility of their concerted action in mediating FAA
Tracing magnetism and pairing in FeTe-based systems
In order to examine the interplay between magnetism and superconductivity, we
monitor the non- superconducting chalcogenide FeTe and follow its transitions
under insertion of oxygen, doping with Se and vacancies of Fe using
spin-polarized band structure methods (LSDA with GGA) starting from the
collinear and bicollinear magnetic arrangements. We use a supercell of Fe8Te8
as our starting point so that it can capture local changes in magnetic moments.
The calculated values of magnetic moments agree well with available
experimental data while oxygen insertions lead to significant changes in the
bicollinear or collinear magnetic moments. The total energies of these systems
indicate that the collinear-derived structure is the more favorable one prior
to a possible superconducting transition. Using a 8-site Betts-cluster-based
lattice and the Hubbard model, we show why this structure favors electron or
hole pairing and provides clues to a common understanding of charge and spin
pairing in the cuprates, pnictides and chalcogenides
Magnetism and its microscopic origin in iron-based high-temperature superconductors
High-temperature superconductivity in the iron-based materials emerges from,
or sometimes coexists with, their metallic or insulating parent compound
states. This is surprising since these undoped states display dramatically
different antiferromagnetic (AF) spin arrangements and Nel
temperatures. Although there is general consensus that magnetic interactions
are important for superconductivity, much is still unknown concerning the
microscopic origin of the magnetic states. In this review, progress in this
area is summarized, focusing on recent experimental and theoretical results and
discussing their microscopic implications. It is concluded that the parent
compounds are in a state that is more complex than implied by a simple Fermi
surface nesting scenario, and a dual description including both itinerant and
localized degrees of freedom is needed to properly describe these fascinating
materials.Comment: 14 pages, 4 figures, Review article, accepted for publication in
Nature Physic
Electronic Origin of High Temperature Superconductivity in Single-Layer FeSe Superconductor
The latest discovery of high temperature superconductivity signature in
single-layer FeSe is significant because it is possible to break the
superconducting critical temperature ceiling (maximum Tc~55 K) that has been
stagnant since the discovery of Fe-based superconductivity in 2008. It also
blows the superconductivity community by surprise because such a high Tc is
unexpected in FeSe system with the bulk FeSe exhibiting a Tc at only 8 K at
ambient pressure which can be enhanced to 38 K under high pressure. The Tc is
still unusually high even considering the newly-discovered intercalated FeSe
system A_xFe_{2-y}Se_2 (A=K, Cs, Rb and Tl) with a Tc at 32 K at ambient
pressure and possible Tc near 48 K under high pressure. Particularly
interesting is that such a high temperature superconductivity occurs in a
single-layer FeSe system that is considered as a key building block of the
Fe-based superconductors. Understanding the origin of high temperature
superconductivity in such a strictly two-dimensional FeSe system is crucial to
understanding the superconductivity mechanism in Fe-based superconductors in
particular, and providing key insights on how to achieve high temperature
superconductivity in general. Here we report distinct electronic structure
associated with the single-layer FeSe superconductor. Its Fermi surface
topology is different from other Fe-based superconductors; it consists only of
electron pockets near the zone corner without indication of any Fermi surface
around the zone center. Our observation of large and nearly isotropic
superconducting gap in this strictly two-dimensional system rules out existence
of node in the superconducting gap. These results have provided an unambiguous
case that such a unique electronic structure is favorable for realizing high
temperature superconductivity
HGF Mediates the Anti-inflammatory Effects of PRP on Injured Tendons
Platelet-rich plasma (PRP) containing hepatocyte growth factor (HGF) and other growth factors are widely used in orthopaedic/sports medicine to repair injured tendons. While PRP treatment is reported to decrease pain in patients with tendon injury, the mechanism of this effect is not clear. Tendon pain is often associated with tendon inflammation, and HGF is known to protect tissues from inflammatory damages. Therefore, we hypothesized that HGF in PRP causes the anti-inflammatory effects. To test this hypothesis, we performed in vitro experiments on rabbit tendon cells and in vivo experiments on a mouse Achilles tendon injury model. We found that addition of PRP or HGF decreased gene expression of COX-1, COX-2, and mPGES-1, induced by the treatment of tendon cells in vitro with IL-1β. Further, the treatment of tendon cell cultures with HGF antibodies reduced the suppressive effects of PRP or HGF on IL-1β-induced COX-1, COX-2, and mPGES-1 gene expressions. Treatment with PRP or HGF almost completely blocked the cellular production of PGE2 and the expression of COX proteins. Finally, injection of PRP or HGF into wounded mouse Achilles tendons in vivo decreased PGE2 production in the tendinous tissues. Injection of platelet-poor plasma (PPP) however, did not reduce PGE2 levels in the wounded tendons, but the injection of HGF antibody inhibited the effects of PRP and HGF. Further, injection of PRP or HGF also decreased COX-1 and COX-2 proteins. These results indicate that PRP exerts anti-inflammatory effects on injured tendons through HGF. This study provides basic scientific evidence to support the use of PRP to treat injured tendons because PRP can reduce inflammation and thereby reduce the associated pain caused by high levels of PGE2. © 2013 Zhang et al
Development of Trust in an Online Breast Cancer Forum: A Qualitative Study
Background: Online health forums provide peer support for a range of medical conditions, including
life-threatening and terminal illnesses. Trust is an important component of peer-to-peer support,
although relatively little is known about how trust forms within online health forums.
Objective: The aim of this paper is to examine how trust develops and influences sharing among
users of an online breast cancer forum.
Methods: An interpretive qualitative approach was adopted. Data were collected from forum posts
from 135 threads on nine boards on the UK charity, Breast Cancer Care (BCC). Semi-structured
interviews were conducted with 14 BCC forum users. Both datasets were analysed thematically using
Braun and Clarke’s [2006] approach and combined to triangulate analysis.
Results: Trust operates in three dimensions, structural, relational and temporal, which intersect with
each other and do not operate in isolation. The structural dimension relates to how the affordances
and formal rules of the site affected trust. The relational dimension refers to how trust was
necessarily experienced in interactions with other forum users: it emerged within relationships and
was a social phenomenon. The temporal dimension relates to how trust changed over time and was
influenced by the length of time users spent on the forum.
Conclusions: Trust is a process that changes over time, and which is influenced by structural features
of the forum and informal but collectively understood relational interactions among forum users.
The study provides a better understanding of how the intersecting structural, relational and
temporal aspects that support the development of trust facilitate sharing in online environments.
These findings will help organisations developing online health forums
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02 TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1 μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos2Δϕ modulation for all ΣETPb ranges and particle pT
Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at s√=8 TeV with the ATLAS detector
The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1fb−1 of proton–proton collision data at √s = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via t˜→tχ˜01 or t˜→ bχ˜±1 →bW(∗)χ˜01 , where χ˜01 (χ˜±1 ) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of t˜ → tχ˜01 . For a branching fraction of 100%, top squark masses in the range 270–645 GeV are excluded for χ˜01 masses below 30 GeV. For a branching fraction of 50% to either t˜ → tχ˜01 or t˜ → bχ˜±1 , and assuming the χ˜±1 mass to be twice the χ˜01 mass, top squark masses in the range 250–550 GeV are excluded for χ˜01 masses below 60 GeV
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