1,583 research outputs found
LANDSAT menhaden and thread herring resources investigation, Gulf of Mexico
The author has identified the following significant results. The most significant achievements thus far include the successful charting of high probability fishing areas from LANDSAT MSS data and the successful simulation of an operational satellite system to provide tactical information for the commercial harvest of menhaden
LANDSAT menhaden and thread herring resources investigation
The author has identified the following significant results. The relationship between the distribution of menhaden and selected oceanographic parameters (water color, turbidity, and possibly chlorophyll concentrations) was established. Similar relationships for thread herring were not established nor were relationships relating to the abundance of either species. Use of aircraft and LANDSAT remote sensing instruments to measure or infer a set of basic oceanographic parameters was evaluated. Parameters which could be accurately inferred included surface water temperature, salinity, and color. Water turbidity (Secchi disk) was evaluated as marginally inferrable from the LANDSAT MSS data and chlorophyll-a concentrations as less than marginal. These evaluations considered the parameters only as experienced in the two test areas using available sensors and statistical techniques
Coarse Graining of Nonbonded Inter-particle Potentials Using Automatic Simplex Optimization to Fit Structural Properties
We implemented a coarse-graining procedure to construct mesoscopic models of
complex molecules. The final aim is to obtain better results on properties
depending on slow modes of the molecules. Therefore the number of particles
considered in molecular dynamics simulations is reduced while conserving as
many properties of the original substance as possible. We address the problem
of finding nonbonded interaction parameters which reproduce structural
properties from experiment or atomistic simulations. The approach consists of
optimizing automatically nonbonded parameters using the simplex algorithm to
fit structural properties like the radial distribution function as target
functions. Moreover, any mix of structural and thermodynamic properties can be
included in the target function. Different spherically symmetric inter-particle
potentials are discussed. Besides demonstrating the method for Lennard--Jones
liquids, it is applied to several more complex molecular liquids such as
diphenyl carbonate, tetrahydrofurane, and monomers of poly(isoprene).Comment: 24 pages, 3 tables, 14 figures submitted to the Journal of Chemical
Physics (JCP
Experimental results for nulling the effective thermal expansion coefficient of fused silica fibres under a static stress
We have experimentally demonstrated that the effective thermal expansion coefficient of a fused silica fibre can be nulled by placing the fibre under a particular level of stress. Our technique involves heating the fibre and measuring how the fibre length changes with temperature as the stress on the fibre was systematically varied. This nulling of the effective thermal expansion coefficient should allow for the complete elimination of thermoelastic noise and is essential for allowing second generation gravitational wave detectors to reach their target sensitivity. To our knowledge this is the first time that the cancelation of the thermal expansion coefficient with stress has been experimentally observed
Stratified spatiotemporal chaos in anisotropic reaction-diffusion systems
Numerical simulations of two dimensional pattern formation in an anisotropic
bistable reaction-diffusion medium reveal a new dynamical state, stratified
spatiotemporal chaos, characterized by strong correlations along one of the
principal axes. Equations that describe the dependence of front motion on the
angle illustrate the mechanism leading to stratified chaos
Granular spirals on erodible sand bed submitted to a circular fluid motion
An experimental study of a granular surface submitted to a circular fluid
motion is presented. The appearance of an instability along the sand-water
interface is observed beyond a critical radius . This creates ripples with
a spiral shape on the granular surface. A phase diagram of such patterns is
constructed and discussed as a function of the rotation speed of the
flow and as a function of the height of water above the surface. The study
of as a function of , and parameters is reported.
Thereafter, is shown to depend on the rotation speed according to a power
law. The ripple wavelength is found to decrease when the rotation speed
increases and is proportional to the radial distance . The azimuthal angle
\az of the spiral arms is studied. It is found that \az scales with . This lead to the conclusion that \az depends on the fluid momentum.
Comparison with experiments performed with fluids allows us to state that the
spiral patterns are not the signature of an instability of the boundary layer.Comment: 7 pages, 10 figures, 1 table, using RevTeX4, submitted for
publication (2002
Detection, Measurement and Gravitational Radiation
Here I examine how to determine the sensitivity of the LIGO, VIRGO, and LAGOS
gravitational wave detectors to sources of gravitational radiation by
considering the process by which data are analyzed in a noisy detector. By
constructing the probability that the detector output is consistent with the
presence of a signal, I show how to (1) quantify the uncertainty that the
output contains a signal and is not simply noise, and (2) construct the
probability distribution that the signal parameterization has a certain value.
From the distribution and its mode I determine volumes in parameter
space such that actual signal parameters are in with probability . If
we are {\em designing} a detector, or determining the suitability of an
existing detector for observing a new source, then we don't have detector
output to analyze but are interested in the ``most likely'' response of the
detector to a signal. I exploit the techniques just described to determine the
``most likely'' volumes for detector output corresponding to the source.
Finally, as an example, I apply these techniques to anticipate the sensitivity
of the LIGO and LAGOS detectors to the gravitational radiation from a perturbed
Kerr black hole.Comment: 37 pages (plus 6 figures), LaTeX/REVTE
Klotho pathways, myelination disorders, neurodegenerative diseases, and epigenetic drugs
In this review we outline a rationale for identifying neuroprotectants aimed at inducing endogenous Klotho activity and expression, which is epigenetic action, by definition. Such an approach should promote remyelination and/or stimulate myelin repair by acting on mitochondrial function, thereby heralding a life-saving path forward for patients suffering from neuroinflammatory diseases. Disorders of myelin in the nervous system damage the transmission of signals, resulting in loss of vision, motion, sensation, and other functions depending on the affected nerves, currently with no effective treatment. Klotho genes and their single-pass transmembrane Klotho proteins are powerful governors of the threads of life and death, true to the origin of their name, Fates, in Greek mythology. Among its many important functions, Klotho is an obligatory co-receptor that binds, activates, and/or potentiates critical fibroblast growth factor activity. Since the discovery of Klotho a little over two decades ago, it has become ever more apparent that when Klotho pathways go awry, oxidative stress and mitochondrial dysfunction take over, and age-related chronic disorders are likely to follow. The physiological consequences can be wide ranging, potentially wreaking havoc on the brain, eye, kidney, muscle, and more. Central nervous system disorders, neurodegenerative in nature, and especially those affecting the myelin sheath, represent worthy targets for advancing therapies that act upon Klotho pathways. Current drugs for these diseases, even therapeutics that are disease modifying rather than treating only the symptoms, leave much room for improvement. It is thus no wonder that this topic has caught the attention of biomedical researchers around the world.https://www.liebertpub.com/doi/10.1089/biores.2020.0004Published versio
Phase chaos in the anisotropic complex Ginzburg-Landau Equation
Of the various interesting solutions found in the two-dimensional complex
Ginzburg-Landau equation for anisotropic systems, the phase-chaotic states show
particularly novel features. They exist in a broader parameter range than in
the isotropic case, and often even broader than in one dimension. They
typically represent the global attractor of the system. There exist two
variants of phase chaos: a quasi-one dimensional and a two-dimensional
solution. The transition to defect chaos is of intermittent type.Comment: 4 pages RevTeX, 5 figures, little changes in figures and references,
typos removed, accepted as Rapid Commun. in Phys. Rev.
On the Correlations between Flavour Observables in Minimal U(2)^3 Models
The stringent correlations between flavour observables in models with CMFV
are consistent with the present data except for the correlation Delta
M_{s,d}-epsilon_K. Motivated by the recent work of Barbieri et al, we compare
the CMFV correlations with the ones present in a special class of models with
an approximate global U(2)^3 flavour symmetry, constrained by a minimal set of
spurions governing the breakdown of this symmetry and the assumption that only
SM operators are relevant in flavour physics. This analog of CMFV to be called
MU(2)^3 allows to avoid the Delta M_{s,d}-epsilon_K tension in question because
of reduced flavour symmetry and implied non-MFV contributions to Delta M_{s,d}.
While the patterns of flavour violation in K meson system is the same as in
CMFV models, the CP-violation in B_{s,d} meson systems can deviate from the one
in the SM and CMFV models. We point out a stringent triple S_{psi K_S}-S_{psi
phi}-|V_ub| correlation in this class of models that could in the future
provide a transparent distinction between different MU(2)^3 models and in the
context of these models determine |V_ub| by means of precise measurements of
S_{psi K_S} and S_{psi phi} with only small hadronic uncertainties. For fixed
S_{psi K_S} the correlation between B(B^+ -> tau^+nu_tau) and S_{psi phi}
follows. We also find that MU(2)^3 models could in principle accommodate a
negative value of S_{psi phi}, provided |V_ub| is found to be in the ballpark
of exclusive determinations and the particular MU(2)^3 model provides a 25%
enhancement of epsilon_K. A supersymmetric U(2)^3 model worked out in the
Barbieri-School appears to satisfy these requirements. However if B(B^+ ->
tau^+nu_tau)>1.0 10^{-4} will be confirmed by future experiments only positive
S_{psi phi} is allowed in this framework. We summarize briefly the pattern of
flavour violation in rare K and B_{s,d} decays in MU(2)^3 models.Comment: 28 pages, 6 figures; v2: Few references and discussion on CP
violation in B_s-> mu^+ mu^- added; v3: Several clarifying comments added,
conclusions unchanged, version accepted for publication in JHE
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