575 research outputs found
Guidance on Design and Construction of the Built Environment Against Wildland Urban Interface Fire Hazard: A Review
Wildland-Urban Interface (WUI) fires, a worldwide problem, are gaining more importance over time due to climate change and increased urbanization in WUI areas. Some jurisdictions have provided standards, codes and guidelines, which may greatly help planning, prevention and protection against wildfires. This work presents a wide systematic review of standards, codes and guidelines for the design and construction of the built environment against WUI fire hazard from North American, European, Oceanic countries, alongside with trans-national codes. The main information reviewed includes: the definition of WUI hazards, risk areas and related severity classes, the influence of land and environmental factors, the requirements for building materials, constructions, utilities, fire protection measures and road access. Some common threads among the documents reviewed have been highlighted. They include similar attempts at: (a) defining WUI risk areas and severity classes, (b) considering land factors including the defensible space (also known as ignition zones), (c) prescribing requirements for buildings and access. The main gaps highlighted in the existing standards/guidelines include lacks of detailed and widespread requirements for resources, fire protection measures, and lacks of taking into account environmental factors in detail. The main design and construction principles contained in the reviewed documents are largely based on previous research and/or good practices. Hence, the main contributions of this paper consist in: (a) systematically disseminate these guidance concepts, (b) setting a potential basis for the development of standards/guidelines in other jurisdictions lacking dedicated WUI fire design guidance, (c) highlighting gaps in existing standards/guidelines to be addressed by current and future research
Intermittent exploration on a scale-free network
We study an intermittent random walk on a random network of scale-free degree
distribution. The walk is a combination of simple random walks of duration
and random long-range jumps. While the time the walker needs to cover all
the nodes increases with , the corresponding time for the edges displays a
non monotonic behavior with a minimum for some nontrivial value of . This
is a heterogeneity-induced effect that is not observed in homogeneous
small-world networks. The optimal increases with the degree of
assortativity in the network. Depending on the nature of degree correlations
and the elapsed time the walker finds an over/under-estimate of the degree
distribution exponent.Comment: 12 pages, 3 figures, 1 table, published versio
New prognosis inflammatory and nutritional indexes: comparison with the Prognostic Inflammatory and Nutritional Index as reference index
Geometry-controlled kinetics
It has long been appreciated that transport properties can control reaction
kinetics. This effect can be characterized by the time it takes a diffusing
molecule to reach a target -- the first-passage time (FPT). Although essential
to quantify the kinetics of reactions on all time scales, determining the FPT
distribution was deemed so far intractable. Here, we calculate analytically
this FPT distribution and show that transport processes as various as regular
diffusion, anomalous diffusion, diffusion in disordered media and in fractals
fall into the same universality classes. Beyond this theoretical aspect, this
result changes the views on standard reaction kinetics. More precisely, we
argue that geometry can become a key parameter so far ignored in this context,
and introduce the concept of "geometry-controlled kinetics". These findings
could help understand the crucial role of spatial organization of genes in
transcription kinetics, and more generally the impact of geometry on
diffusion-limited reactions.Comment: Submitted versio
First-principles derivation of the AdS/CFT Y-systems
We provide a first-principles, perturbative derivation of the AdS5/CFT4
Y-system that has been proposed to solve the spectrum problem of N=4 SYM. The
proof relies on the computation of quantum effects in the fusion of some loop
operators, namely the transfer matrices. More precisely we show that the
leading quantum corrections in the fusion of transfer matrices induce the
correct shifts of the spectral parameter in the T-system. As intermediate steps
we study UV divergences in line operators up to first order and compute the
fusion of line operators up to second order for the pure spinor string in
AdS5xS5. We also argue that the derivation can be easily extended to other
integrable models, some of which describe string theory on AdS4, AdS3 and AdS2
spacetimes.Comment: 45 pages, 5 figures; v2: minor additions, JHEP versio
Liver regeneration in dogs: Morphologic and chemical changes
Forty-four percent and 72% hepatectomy were carried out in dogs and the animals were sacrificed for biochemical and pathologic studies from 0.5 to 6 days later. Compensatory hypertrophy and hyperplasia ("regeneration") were evident within 1 day, reached a maximum in 3 days, and were almost complete by 6 days. Coincident with the histologic events of regeneration were decreases in responsiveness of receptor adenyl cyclase to glucagon stimulation, increases of cyclic AMP, inconsistent changes in plasma insulin, and increases in plasma glucagon. These studies have standardized hepatic resection in dogs and they have focused attention upon some possible mechanisms that will require further study. © 1978 Academic Press, Inc. All rights of reserved
The influence of D-branes' backreaction upon gravitational interactions between open strings
We argue that gravitational interactions between open strings ending on
D3-branes are largely shaped by the D3-branes' backreaction. To this end we
consider classical open strings coupled to general relativity in Poincare AdS5
backgrounds. We compute the linear gravitational backreaction of a static
string extending up to the Poincare horizon, and deduce the potential energy
between two such strings. If spacetime is non-compact, we find that the
gravitational potential energy between parallel open strings is independent of
the strings' inertial masses and goes like 1/r at large distance r. If the
space transverse to the D3-branes is suitably compactified, a collective mode
of the graviton propagates usual four-dimensional gravity. In that case the
backreaction of the D3-branes induces a correction to the Newtonian potential
energy that violates the equivalence principle. The observed enhancement of the
gravitational attraction is specific to string theory; there is no similar
effect for point-particles.Comment: 28 pages, 7 figures. Typos corrected, minor addition
The transplantation of gastrointestinal organs
Over a period of 33 years, it has become possible to successfully transplant individual intra-abdominal viscera or combinations of these organs. The consequences have been, first, new information about the metabolic interrelations that the visceral organs have in disease or health; second, the addition of several procedures to the treatment armamentarium of gastrointestinal diseases; and third, a more profound understanding of the means by which all whole organ grafts are accepted. © 1993
Geometry of open strings ending on backreacting D3-branes
We investigate open string theory on backreacting D3-branes using a spacetime
approach. We study in detail the half-BPS supergravity solutions describing
open strings ending on D3-branes, in the near horizon of the D3-branes. We
recover quantitatively several non-trivial features of open string physics
including the appearance of D3-brane spikes, the polarization of fundamental
strings into D5-branes, and the Hanany-Witten effect. Finally we detail the
computation of the gravitational potential between two open strings, and
contrast it with the holographic computation of Wilson lines. We argue that the
D-brane backreaction has a large influence on the low-energy gravity, which may
lead to experimental tests for string theory brane-world scenarios.Comment: 64 pages, 20 figure
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