394 research outputs found
A role for TGFÎČ-RII/MCP-5 axis during post traumatic osteoarthritis and potential role of PTHrP in mediating MCP-5 effect
The High Redshift Integrated Sachs-Wolfe Effect
In this paper we rely on the quasar (QSO) catalog of the Sloan Digital Sky
Survey Data Release Six (SDSS DR6) of about one million photometrically
selected QSOs to compute the Integrated Sachs-Wolfe (ISW) effect at high
redshift, aiming at constraining the behavior of the expansion rate and thus
the behaviour of dark energy at those epochs. This unique sample significantly
extends previous catalogs to higher redshifts while retaining high efficiency
in the selection algorithm. We compute the auto-correlation function (ACF) of
QSO number density from which we extract the bias and the stellar
contamination. We then calculate the cross-correlation function (CCF) between
QSO number density and Cosmic Microwave Background (CMB) temperature
fluctuations in different subsamples: at high z>1.5 and low z<1.5 redshifts and
for two different choices of QSO in a conservative and in a more speculative
analysis. We find an overall evidence for a cross-correlation different from
zero at the 2.7\sigma level, while this evidence drops to 1.5\sigma at z>1.5.
We focus on the capabilities of the ISW to constrain the behaviour of the dark
energy component at high redshift both in the \LambdaCDM and Early Dark Energy
cosmologies, when the dark energy is substantially unconstrained by
observations. At present, the inclusion of the ISW data results in a poor
improvement compared to the obtained constraints from other cosmological
datasets. We study the capabilities of future high-redshift QSO survey and find
that the ISW signal can improve the constraints on the most important
cosmological parameters derived from Planck CMB data, including the high
redshift dark energy abundance, by a factor \sim 1.5.Comment: 20 pages, 18 figures, and 7 table
Random walks and polymers in the presence of quenched disorder
After a general introduction to the field, we describe some recent results
concerning disorder effects on both `random walk models', where the random walk
is a dynamical process generated by local transition rules, and on `polymer
models', where each random walk trajectory representing the configuration of a
polymer chain is associated to a global Boltzmann weight. For random walk
models, we explain, on the specific examples of the Sinai model and of the trap
model, how disorder induces anomalous diffusion, aging behaviours and Golosov
localization, and how these properties can be understood via a strong disorder
renormalization approach. For polymer models, we discuss the critical
properties of various delocalization transitions involving random polymers. We
first summarize some recent progresses in the general theory of random critical
points : thermodynamic observables are not self-averaging at criticality
whenever disorder is relevant, and this lack of self-averaging is directly
related to the probability distribution of pseudo-critical temperatures
over the ensemble of samples of size . We describe the
results of this analysis for the bidimensional wetting and for the
Poland-Scheraga model of DNA denaturation.Comment: 17 pages, Conference Proceedings "Mathematics and Physics", I.H.E.S.,
France, November 200
Exploring leadership in multi-sectoral partnerships
This article explores some critical aspects of leadership in the context of multi-sectoral partnerships. It focuses on leadership in practice and asks the question, `How do managers experience and perceive leadership in such partnerships?' The study contributes to the debate on whether leadership in a multi-sectoral partnership context differs from that within a single organization. It is based on the accounts of practising managers working in complex partnerships. The article highlights a number of leadership challenges faced by those working in multi-sectoral partnerships. Partnership practitioners were clear that leadership in partnerships was more complex than in single organizations. However, it was more difficult for them to agree a consensus on the essential nature of leadership in partnership. We suggest that a first-, second- and third-person approach might be a way of better interpreting leadership in the context of partnerships
Electrified Fuzzy Spheres and Funnels in Curved Backgrounds
We use the non-Abelian DBI action to study the dynamics of coincident
-branes in an arbitrary curved background, with the presence of a
homogenous world-volume electric field. The solutions are natural extensions of
those without electric fields, and imply that the spheres will collapse toward
zero size. We then go on to consider the intersection in a curved
background and find various dualities and automorphisms of the general
equations of motion. It is possible to map the dynamical equation of motion to
the static one via Wick rotation, however the additional spatial dependence of
the metric prevents this mapping from being invertible. Instead we find that a
double Wick rotation leaves the static equation invariant. This is very
different from the behaviour in Minkowski space. We go on to construct the most
general static fuzzy funnel solutions for an arbitrary metric either by solving
the static equations of motion, or by finding configurations which minimise the
energy. As a consistency check we construct the Abelian -brane world-volume
theory in the same generic background and find solutions consistent with energy
minimisation. In the 5-brane background we find time dependent solutions to
the equations of motion, representing a time dependent fuzzy funnel. These
solutions match those obtained from the -string picture to leading order
suggesting that the action in the large limit does not need corrections. We
conclude by generalising our solutions to higher dimensional fuzzy funnels.Comment: 38 pages, Latex; references adde
Boundary States for D-branes with Traveling Waves
We construct boundary states for D-branes which carry traveling waves in the
covariant formalism. We compute their vacuum amplitudes to investigate their
interactions. In non-compact space, the vacuum amplitudes become trivial as is
common in plane wave geometries. However, we found that if they are
compactified in the traveling direction, then the amplitudes are affected by
non-trivial time dependent effects. The interaction between D-branes with waves
traveling in the opposite directions (`pulse-antipulse scattering') are also
computed. Furthermore, we apply these ideas to open string tachyon condensation
with traveling waves.Comment: 30 pages. 1 figure, Latex, minor corrections, references adde
Microstructure and thermal stability of Fe, Ti and Ag implanted Yttria-stabilized zirconia
Yttria-stabilized zirconia (YSZ) was implanted with 15 keV Fe or Ti ions up to a dose of 8Ă1016 at cmâ2. The resulting âdopantâ concentrations exceeded the concentrations corresponding to the equilibrium solid solubility of Fe2O3 or TiO2 in YSZ. During oxidation in air at 400° C, the Fe and Ti concentration in the outermost surface layer increased even further until a surface layer was formed of mainly Fe2O3 and TiO2, as shown by XPS and ISS measurements. From the time dependence of the Fe and Ti depth profiles during anneal treatments, diffusion coefficients were calculated. From those values it was estimated that the maximum temperature at which the Fe- and Ti-implanted layers can be operated without changes in the dopant concentration profiles was 700 and 800° C, respectively. The high-dose implanted layer was completely amorphous even after annealing up to 1100° C, as shown by scanning transmission electron microscopy. Preliminary measurements on 50 keV Ag implanted YSZ indicate that in this case the amorphous layer recrystallizes into fine grained cubic YSZ at a temperature of about 1000° C. The average grain diameter was estimated at 20 nm, whereas the original grain size of YSZ before implantation was 400 nm. This result implies that the grain size in the surface of a ceramic material can be decreased by ion beam amorphisation and subsequent recrystallisation at elevated temperatures
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
Fire as a fundamental ecological process: Research advances and frontiers
Fire is a powerful ecological and evolutionary force that regulates organismal traits, population sizes, species interactions, community composition, carbon and nutrient cycling and ecosystem function. It also presents a rapidly growing societal challenge, due to both increasingly destructive wildfires and fire exclusion in fireâdependent ecosystems. As an ecological process, fire integrates complex feedbacks among biological, social and geophysical processes, requiring coordination across several fields and scales of study.
Here, we describe the diversity of ways in which fire operates as a fundamental ecological and evolutionary process on Earth. We explore research priorities in six categories of fire ecology: (a) characteristics of fire regimes, (b) changing fire regimes, (c) fire effects on aboveâground ecology, (d) fire effects on belowâground ecology, (e) fire behaviour and (f) fire ecology modelling.
We identify three emergent themes: the need to study fire across temporal scales, to assess the mechanisms underlying a variety of ecological feedbacks involving fire and to improve representation of fire in a range of modelling contexts.
Synthesis : As fire regimes and our relationships with fire continue to change, prioritizing these research areas will facilitate understanding of the ecological causes and consequences of future fires and rethinking fire management alternatives
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