1,908 research outputs found
Conformal Wasserstein distances: comparing surfaces in polynomial time
We present a constructive approach to surface comparison realizable by a
polynomial-time algorithm. We determine the "similarity" of two given surfaces
by solving a mass-transportation problem between their conformal densities.
This mass transportation problem differs from the standard case in that we
require the solution to be invariant under global M\"{o}bius transformations.
We present in detail the case where the surfaces to compare are disk-like; we
also sketch how the approach can be generalized to other types of surfaces.Comment: 23 pages, 3 figure
Cannabis through the looking glass: chemo- and enantio-selective separation of phytocannabinoids by enantioselective ultra high performance supercritical fluid chromatography
By using the Inverted Chirality Columns Approach (ICCA) we have developed an enantioselective UHPSFC method to determine the enantiomeric excess (ee) of (-)-Δ(9)-THC in medicinal marijuana (Bedrocan®). The ee was high (99.73%), but the concentration of the (+)-enantiomer (0.135%) was not negligible, and it is worth a systematic evaluation of bioactivity
Dismenorrea in donne lavoratrici dell'industria
La dismenorrea è una delle più comuni indisposizioni nelle donne. La frequenza varia in differenti lavori, probabilmente ciò è dovuto alla differenza nei gruppi di popolazione studiati. In alcune industrie Norvegesi, con molto personale femminile, l’inabilità periodica al lavoro dovuto ai fastidi mestruali è stato un problema di una
certa importanza e la domanda è sorta nel caso in cui l’assenza è medicalmente giustificata nella visione di un moderno trattamento ormonale. Per avvicinarci al problema abbiamo pianificato di esaminare l’evento dei fastidi mestruali, particolarmente la dismenorrea, tra il personale femminile in alcune industrie Italiane in quello che appariva essere un problema. I soggetti esaminati erano impiegati di una compagnia elettrica-tecnica e di una
industria tessile. Un questionario preparato da una infermiera dell’industria, è stato compilato da donne in età mestruale che erano state visitate per esami medici periodici e di pre-assunzione tra il 2002-2003. Ogni donna assistita soffriva di dolore, e quando tutti i sintomi erano considerati il 61% aveva mensilmente disturbi che ovviamente riducevano la loro capacità sul lavoro.
Visto che il 9% delle donne assumevano estroprogestinici, che riducevano o eliminavano la dismenorrea, la vera prevalenza potrebbe essere leggermente superiore. Circa il 30% delle donne erano confinate a letto. Circa il 30% si assentava dal lavoro, il che illustra la grandezza del problema sia medico che economico
Structure, Scaling and Phase Transition in the Optimal Transport Network
We minimize the dissipation rate of an electrical network under a global
constraint on the sum of powers of the conductances. We construct the explicit
scaling relation between currents and conductances, and show equivalence to a a
previous model [J. R. Banavar {\it et al} Phys. Rev. Lett. {\bf 84}, 004745
(2000)] optimizing a power-law cost function in an abstract network. We show
the currents derive from a potential, and the scaling of the conductances
depends only locally on the currents. A numerical study reveals that the
transition in the topology of the optimal network corresponds to a
discontinuity in the slope of the power dissipation.Comment: 4 pages, 3 figure
Interpolative Approach for Solving the Anderson Impurity Model
A rational representation for the self--energy is explored to interpolate the
solution of the Anderson impurity model in general orbitally degenerate case.
Several constrains such as the Friedel's sum rule, positions of the Hubbard
bands as well as the value of quasiparticle residue are used to establish the
equations for the coefficients of the interpolation. We employ two fast
techniques, the slave--boson mean--field and the Hubbard I approximations to
determine the functional dependence of the coefficients on doping, degeneracy
and the strength of the interaction. The obtained spectral functions and
self--energies are in good agreement with the results of numerically exact
quantum Monte Carlo method.Comment: 15 pages, 9 figure
The dissipative linear Boltzmann equation for hard spheres
We prove the existence and uniqueness of an equilibrium state with unit mass
to the dissipative linear Boltzmann equation with hard--spheres collision
kernel describing inelastic interactions of a gas particles with a fixed
background. The equilibrium state is a universal Maxwellian distribution
function with the same velocity as field particles and with a non--zero
temperature lower than the background one, which depends on the details of the
binary collision. Thanks to the H--theorem we then prove strong convergence of
the solution to the Boltzmann equation towards the equilibrium.Comment: 17 pages, submitted to Journal of Statistical Physic
Dynamic HPLC on chiral stationary phases: a powerful tool for the investigation of stereomutation processes
Dynamic HPLC on enantioselective stationary phases has become a well-established technique to investigate chiral molecules with internal motions that result in stereoinversion and occur on the time scale of the separation process. Kinetic parameters
for the on-column interconversion phenomena can be extracted from experimental peak profiles by computer simulation or by direct calculation methods. The technique has been used in a wide range of temperatures and is complementary in scope to dynamic NMR spectroscopy
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