7,609 research outputs found
Active fillersâ effect on in situ performances of foam bitumen recycled mixtures
Cold recycling is one of the most employed rehabilitation techniques for asphalt pavements and it is becoming more and more important as reducing emissions becomes a priority in the reduction of the greenhouse effect. The main advantages of asphalt cold recycling techniques are the use of reclaimed materials and the fact that there is no need of aggregate heating to make the mixtures. This paper describes the evolution with time of in-situ performances of different foam bitumen-stabilised mixtures made with different active fillers (cement and lime), monitored during the first year from construction. Results are part of a more extensive research programme aimed to investigate the effects of using lime as an active filler in cold-recycled mixtures. Mixtures have been laid down on a specifically designed trial section in Italy, close to Florence. Short-term bearing capacity, immediately after construction, has been evaluated using a light weight deflectometer while to evaluate the mid-term performances falling weight deflectometer (FWD) tests have been performed after 24 hours, 14 days, 28 days and 9 months from construction. During these 9 months the test road was not opened to traffic, so the mixtures experienced almost no traffic (only construction traffic loads). This fact allowed to have the curing process without any influences other than the temperature: it means same curing conditions for all mixtures. Subsequent FWD tests are still ongoing to evaluate the evolution over time of pavement bearing capacity due to traffic. Results obtained positively support the use of lime as an active filler in the foam bitumen-stabilised material and allow to underline the effect of different active fillers in the material behaviour, even if all the mixtures underline excellent performances under traffic loading. FWD tests are scheduled to be repeated every 6 months in order to monitor the stiffness evolution of the mixtures and evaluate the nature of traffic damage
Polymorphisms in the SULF1 gene are associated with early age of onset and survival of ovarian cancer
<p>Abstract</p> <p>Background</p> <p>SULF1 (sulfatase 1) selectively removes the 6-O-sulphate group from heparan sulfate, changing the binding sites for extracellular growth factors. <it>SULF1 </it>expression has been reported to be decreased in various cancers, including ovarian cancer. We hypothesized that single nucleotide polymorphisms (SNPs) of <it>SULF1 </it>would impact clinicopathologic characteristics.</p> <p>Methods</p> <p>We genotyped five common (minor allele frequency>0.05) regulatory SNPs with predicted functionalities (rs2623047 G>A, rs13264163 A>G, rs6990375 G>A, rs3802278 G>A, and rs3087714 C>T) in 168 patients with primary epithelial ovarian cancer, using the polymerase chain reaction-restriction fragment length polymorphism method.</p> <p>Results</p> <p>We found that rs2623047 G>A was significantly associated with an early age of onset of ovarian cancer in the G allele dose-response manner (<it>P </it>= 0.027; <it>P<sub>trend </sub></it>= 0.007) and that rs2623047 GG/GA genotypes were associated with longer progression-free survival; rs6990375 G>A was also associated with the early age of onset in the A allele dose-response manner (<it>P </it>= 0.013; <it>P<sub>trend</sub></it>= 0.009). The significant differences in age of disease onset persisted among carriers of haplotypes of rs2623047 and rs6990375 (<it>P </it>= 0.014; <it>P<sub>trend </sub></it>= 0.004). In luciferase reporter gene assays, rs2623047 G allele showed a slightly higher promoter activity than the A allele in the SKOV3 tumorigenic cell line.</p> <p>Conclusions</p> <p>These findings suggest that genetic variations in <it>SULF1 </it>may play a role in ovarian cancer onset and prognosis. Further studies with large sample sizes and of the mechanistic relevance of <it>SULF1 </it>SNPs are warranted.</p
The transition temperature of the dilute interacting Bose gas
We show that the critical temperature of a uniform dilute Bose gas must
increase linearly with the s-wave scattering length describing the repulsion
between the particles. Because of infrared divergences, the magnitude of the
shift cannot be obtained from perturbation theory, even in the weak coupling
regime; rather, it is proportional to the size of the critical region in
momentum space. By means of a self-consistent calculation of the quasiparticle
spectrum at low momenta at the transition, we find an estimate of the effect in
reasonable agreement with numerical simulations.Comment: 4 pages, Revtex, to be published in Physical Review Letter
Capacities of noiseless quantum channels for massive indistinguishable particles: Bosons vs. fermions
We consider information transmission through a noiseless quantum channel,
where the information is encoded into massive indistinguishable particles:
bosons or fermions. We study the situation in which the particles are
noninteracting. The encoding input states obey a set of physically motivated
constraints on the mean values of the energy and particle number. In such a
case, the determination of both classical and quantum capacity reduces to a
constrained maximization of entropy. In the case of noninteracting bosons,
signatures of Bose Einstein condensation can be observed in the behavior of the
capacity. A major motivation for these considerations is to compare the
information carrying capacities of channels that carry bosons with those that
carry fermions. We show analytically that fermions generally provide higher
channel capacity, i.e., they are better suited for transferring bits as well as
qubits, in comparison to bosons. This holds for a large range of power law
potentials, and for moderate to high temperatures. Numerical simulations seem
to indicate that the result holds for all temperatures. Also, we consider the
low temperature behavior for the three-dimensional box and harmonic trap, and
again we show that the fermionic capacity is higher than the bosonic one for
sufficiently low temperatures.Comment: 16 pages, 8 eps figures, RevTeX4; v2: small change in a figure; v3:
significant new additions about quantum capacity, previous results unchanged,
title changed, published versio
Free energy barrier for melittin reorientation from a membrane-bound state to a transmembrane state
An important step in a phospholipid membrane pore formation by melittin
antimicrobial peptide is a reorientation of the peptide from a surface into a
transmembrane conformation. In this work we perform umbrella sampling
simulations to calculate the potential of mean force (PMF) for the
reorientation of melittin from a surface-bound state to a transmembrane state
and provide a molecular level insight into understanding peptide and lipid
properties that influence the existence of the free energy barrier. The PMFs
were calculated for a peptide to lipid (P/L) ratio of 1/128 and 4/128. We
observe that the free energy barrier is reduced when the P/L ratio increased.
In addition, we study the cooperative effect; specifically we investigate if
the barrier is smaller for a second melittin reorientation, given that another
neighboring melittin was already in the transmembrane state. We observe that
indeed the barrier of the PMF curve is reduced in this case, thus confirming
the presence of a cooperative effect
Extremely Red Objects in The Lockman Hole
We investigate Extremely Red Objects (EROs) using near- and mid-infrared
observations in five passbands (3.6 to 24 micron) obtained from the Spitzer
Space Telescope, and deep ground-based R and K imaging. The great sensitivity
of the IRAC camera allows us to detect 64 EROs in only 12 minutes of IRAC
exposure time, by means of an R-[3.6] color cut (analogous to the traditional
red R-K cut). A pure infrared K-[3.6] red cut detects a somewhat different
population and may be more effective at selecting z > 1.3 EROs. We find 17% of
all galaxies detected by IRAC at 3.6 or 4.5 micron to be EROs. These
percentages rise to about 40% at 5.8 micron, and about 60% at 8.0 micron. We
utilize the spectral bump at 1.6 micron to divide the EROs into broad redshift
slices using only near-infrared colors (2.2/3.6/4.5 micron). We conclude that
two-thirds of all EROs lie at redshift z > 1.3. Detections at 24 micron imply
that at least 11% of 0.6 1.3 EROs are
dusty star-forming galaxies.Comment: to appear in the special Spitzer issue of the ApJ
IRAC Imaging of Lockman Hole
IRAC imaging of a 4'7x4'7 area in the Lockman Hole detected over 400 galaxies
in the IRAC 3.6 micron and 4.5 micron bands, 120 in the 5.8 micron, and 80 in
the 8 micron bandin 30 minutes of observing time. Color-color diagrams suggest
that about half of these galaxies are at redshifts 0.6<z<1.3 with about a
quarter at higher redshifts (z>1.3). We also detect IRAC counterparts for 6 of
the 7 SCUBA sources and all 9 XMM sources in this area. The detection of the
counterparts of the SCUBA sources and galaxies at z>1.3 demonstrates the
ability of IRAC to probe the universe at very high redshifts.Comment: 11 pages, 2 figures. accepted by ApJS, Spizter Special Issu
Ocean circulation and Tropical Variability in the Coupled Model ECHAM5/MPI-OM
This paper describes the mean ocean circulation and the tropical variability simulated by the Max Planck Institute for Meteorology (MPI-M) coupled atmosphereâocean general circulation model (AOGCM). Results are presented from a version of the coupled model that served as a prototype for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) simulations. The model does not require flux adjustment to maintain a stable climate. A control simulation with present-day greenhouse gases is analyzed, and the simulation of key oceanic features, such as sea surface temperatures (SSTs), large-scale circulation, meridional heat and freshwater transports, and sea ice are compared with observations.
A parameterization that accounts for the effect of ocean currents on surface wind stress is implemented in the model. The largest impact of this parameterization is in the tropical Pacific, where the mean state is significantly improved: the strength of the trade winds and the associated equatorial upwelling weaken, and there is a reduction of the modelâs equatorial cold SST bias by more than 1 K. Equatorial SST variability also becomes more realistic. The strength of the variability is reduced by about 30% in the eastern equatorial Pacific and the extension of SST variability into the warm pool is significantly reduced. The dominant El NiñoâSouthern Oscillation (ENSO) period shifts from 3 to 4 yr. Without the parameterization an unrealistically strong westward propagation of SST anomalies is simulated. The reasons for the changes in variability are linked to changes in both the mean state and to a reduction in atmospheric sensitivity to SST changes and oceanic sensitivity to wind anomalies
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