22,362 research outputs found
Poly(2-oxazolines) in biological and biomedical application contexts.
Polyoxazolines of various architectures and chemical functionalities can be prepared in a living and therefore controlled manner via cationic ring-opening polymerisation. They have found widespread applications, ranging from coatings to pigment dispersants. Furthermore, several polyoxazolines are water-soluble or amphiphilic and relatively non-toxic, which makes them interesting as biomaterials. This paper reviews the development of polyoxazoline-based polymers in biological and biomedical application contexts since the beginning of the millennium. This includes nanoscalar systems such as membranes and nanoparticles, drug and gene delivery applications, as well as stimuli-responsive systems
Digital analysis of Potomac River Basin ERTS imagery: Sedimentation levels at the Potomac-Anacostia confluence and strip mining in Allegheny County, Maryland
Two simple algorithms for classification of sedimentation levels in water and for delineation of active strip mines are in use as part of the development of a more general resource management information system. ERTS MSS CCT's are processed so that each pixel in each channel is geographically referenced and can be accessed individually during whole frame, multi-channel analysis or partial frame analysis. The sedimentation analysis clearly separates classes representing the turbid Anacostia water, the less disturbed Potomac (really), and mud flats resulting from effluent of a major sewage treatment plant. Mud flats of organic or mineral origin are easily distinguished
The Influence of green areas and roof albedos on air temperatures during Extreme Heat Events in Berlin, Germany
The mesoscale atmospheric model COSMO-CLM (CCLM) with the Double Canyon Effect Parametrization Scheme (DCEP) is applied to investigate possible adaption measures to extreme heat events (EHEs) for the city of Berlin, Germany. The emphasis is on the effects of a modified urban vegetation cover and roof albedo on near-surface air temperatures. Five EHEs with a duration of 5 days or more are identified for the period 2000 to 2009. A reference simulation is carried out for each EHE with current vegetation cover, roof albedo and urban canopy parameters (UCPs), and is evaluated with temperature observations from weather stations in Berlin and its surroundings. The derivation of the UCPs from an impervious surface map and a 3-D building data set is detailed. Characteristics of the simulated urban heat island for each EHE are analysed in terms of these UCPs. In addition, six sensitivity runs are examined with a modified vegetation cover of each urban grid cell by -25%, 5% and 15%, with a roof albedo increased to 0.40 and 0.65, and with a combination of the largest vegetation cover and roof albedo, respectively. At the weather stations' grid cells, the results show a maximum of the average diurnal change in air temperature during each EHE of 0.82 K and -0.48 K for the -25% and 15% vegetation covers, -0.50 K for the roof albedos of 0.65, and -0.63 K for the combined vegetation and albedo case. The largest effects on the air temperature are detected during midday
Mars: Seasonally variable radar reflectivity
The 1971/1973 Mars data set acquired by the Goldstone Solar System Radar was analyzed. It was established that the seasonal variations in radar reflectivity thought to occur in only one locality on the planet (the Solis Lacus radar anomaly) occur, in fact, over the entire subequatorial belt observed by the Goldstone radar. Since liquid water appears to be the most likely cause of the reflectivity excursions, a permanent, year-round presence of subsurface water (frozen or thawed) in the Martian tropics can be inferred
Fractional -scaling for quantum kicked rotors without cantori
Previous studies of quantum delta-kicked rotors have found momentum
probability distributions with a typical width (localization length )
characterized by fractional -scaling, ie in regimes
and phase-space regions close to `golden-ratio' cantori. In contrast, in
typical chaotic regimes, the scaling is integer, . Here we
consider a generic variant of the kicked rotor, the random-pair-kicked particle
(RP-KP), obtained by randomizing the phases every second kick; it has no KAM
mixed phase-space structures, like golden-ratio cantori, at all. Our unexpected
finding is that, over comparable phase-space regions, it also has fractional
scaling, but . A semiclassical analysis indicates that the
scaling here is of quantum origin and is not a signature of
classical cantori.Comment: 5 pages, 4 figures, Revtex, typos removed, further analysis added,
authors adjuste
The state space of short-range Ising spin glasses: the density of states
The state space of finite square and cubic Ising spin glass models is
analysed in terms of the global and the local density of states. Systems with
uniform and gaussian probability distribution of interactions are compared.
Different measures for the local state density are presented and discussed. In
particular the question whether the local density of states grows exponentially
or not is considered. The direct comparison of global and local densities leads
to consequences for the structure of the state space.Comment: 18 pages (including 6 figures); submitted to Z.f.Physik
Sensible and latent heating of the atmosphere as inferred from DST-6 data
The average distribution of convective latent heating, boundary layer sensible heat flux, and vertical velocity are determined for the winter 1976 DST period from GLAS model diagnostics. Key features are the regions of intense latent heating over Brazil, Central Africa, and Indonesia; and the regions of strong sensible heating due to air mass modification over the North Atlantic and North Pacific Oceans
Higgs boson pair production in gluon fusion at NLO with full top-quark mass dependence
We present the calculation of the cross section and invariant mass
distribution for Higgs boson pair production in gluon fusion at next-to-leading
order (NLO) in QCD. Top-quark masses are fully taken into account throughout
the calculation. The virtual two-loop amplitude has been generated using an
extension of the program GoSam supplemented with an interface to Reduze for the
integral reduction. The occurring integrals have been calculated numerically
using the program SecDec. Our results, including the full top-quark mass
dependence for the first time, allow us to assess the validity of various
approximations proposed in the literature, which we also recalculate. We find
substantial deviations between the NLO result and the different approximations,
which emphasizes the importance of including the full top-quark mass dependence
at NLO.Comment: Version published in PRL, v2: results at 13 TeV (v1 was at 14 TeV),
minor correction to virtual part included, conclusions unchange
Anisotropy, phonon modes, and lattice anharmonicity from dielectric function tensor analysis of monoclinic cadmium tungstate
We determine the frequency dependence of four independent CdWO Cartesian
dielectric function tensor elements by generalized spectroscopic ellipsometry
within mid-infrared and far-infrared spectral regions. Single crystal surfaces
cut under different angles from a bulk crystal, (010) and (001), are
investigated. From the spectral dependencies of the dielectric function tensor
and its inverse we determine all long wavelength active transverse and
longitudinal optic phonon modes with and symmetry as well as their
eigenvectors within the monoclinic lattice. We thereby demonstrate that such
information can be obtained completely without physical model line shape
analysis in materials with monoclinic symmetry. We then augment the effect of
lattice anharmonicity onto our recently described dielectric function tensor
model approach for materials with monoclinic and triclinic crystal symmetries
[Phys. Rev. B, 125209 (2016)], and we obtain excellent match between all
measured and modeled dielectric function tensor elements. All phonon mode
frequency and broadening parameters are determined in our model approach. We
also perform density functional theory phonon mode calculations, and we compare
our results obtained from theory, from direct dielectric function tensor
analysis, and from model lineshape analysis, and we find excellent agreement
between all approaches. We also discuss and present static and above
reststrahlen spectral range dielectric constants. Our data for CdWO are in
excellent agreement with a recently proposed generalization of the
Lyddane-Sachs-Teller relation for materials with low crystal symmetry [Phys.
Rev. Lett. 117, 215502 (2016)].Comment: arXiv admin note: text overlap with arXiv:1512.0859
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