Hot air ballon deceleration and recovery system Patent

Development and characteristics of hot air balloon deceleration and recovery syste

Non-perturbative scale evolution of four-fermion operators

We apply the Schroedinger Functional (SF) formalism to determine the renormalisation group running of four-fermion operators which appear in the effective weak Hamiltonian of the Standard Model. Our calculations are done using Wilson fermions and the parity-odd components of the operators. Preliminary results are presented for the operator $O_{VA}=(\bar s \gamma_\mu d)(\bar s \gamma_\mu \gamma_5 d)$.Comment: Lattice2002(improve

Spectral analysis of semigroups and growth-fragmentation equations

The aim of this paper is twofold: (1) On the one hand, the paper revisits the spectral analysis of semigroups in a general Banach space setting. It presents some new and more general versions, and provides comprehensible proofs, of classical results such as the spectral mapping theorem, some (quantified) Weyl's Theorems and the Krein-Rutman Theorem. Motivated by evolution PDE applications, the results apply to a wide and natural class of generators which split as a dissipative part plus a more regular part, without assuming any symmetric structure on the operators nor Hilbert structure on the space, and give some growth estimates and spectral gap estimates for the associated semigroup. The approach relies on some factorization and summation arguments reminiscent of the Dyson-Phillips series in the spirit of those used in [87,82,48,81]. (2) On the other hand, we present the semigroup spectral analysis for three important classes of ''growth-fragmentation" equations, namely the cell division equation, the self-similar fragmentation equation and the McKendrick-Von Foerster age structured population equation. By showing that these models lie in the class of equations for which our general semigroup analysis theory applies, we prove the exponential rate of convergence of the solutions to the associated remarkable profile for a very large and natural class of fragmentation rates. Our results generalize similar estimates obtained in \cite{MR2114128,MR2536450} for the cell division model with (almost) constant total fragmentation rate and in \cite{MR2832638,MR2821681} for the self-similar fragmentation equation and the cell division equation restricted to smooth and positive fragmentation rate and total fragmentation rate which does not increase more rapidly than quadratically. It also improves the convergence results without rate obtained in \cite{MR2162224,MR2114413} which have been established under similar assumptions to those made in the present work

Eocene to Miocene Magnetostratigraphy, Biostratigraphy, and Chemostratigraphy at ODP Site 1090 (Sub-Antarctic South Atlantic)

At Ocean Drilling Program (ODP) Site 1090 (lat 42854.89S, long 8854.09E) locatedin a water depth of 3702 m on the Agulhas Ridge in the sub-Antarctic South Atlantic, ~300 m of middle Eocene to middle Miocenesediments were recovered with the advancedpiston corer (APC) and the extendedcore barrel (XCB). U-channel samplesfrom the 70–230 meters composite depth(mcd) interval provide a magnetic polaritystratigraphy that is extended to 380 mcd byshipboard whole-core and discrete sampledata. The magnetostratigraphy can be interpretedby the fit of the polarity-zone patternto the geomagnetic polarity time scale(GPTS) augmented by isotope data andbioevents with documented correlation tothe GPTS. Three normal-polarity subchrons(C5Dr.1n, C7Ar.1n, and C13r.1n),not included in the standard GPTS, are recordedat Site 1090. The base of the sampledsection is correlated to C19n (middleEocene), although the interpretation is unclearbeyond C17r. The top of the sampledsection is correlated to C5Cn (late earlyMiocene), although, in the uppermost 10 m of the sampled section, a foraminifer (Globorotaliasphericomiozea) usually associatedwith the Messinian and early Pliocene hasbeen identified. 87Sr/86Sr, d13C, and d18Ovalues measured on foraminifera, includingthe d18O and d13C shifts close to the Eocene/Oligocene boundary, support the correlationto the GPTS. For the interval spanningthe Oligocene/Miocene boundary, benthicd13C, d18O, and 87Sr/86Sr records from Site1090 can be correlated to isotope recordsfrom ODP Site 929 (Ceara Rise), providing support for the recently-published Oligocene/Miocene boundary age (22.92 Ma) of Shackleton et al

Changing the culture of care for children and adolescents with functional neurological disorder.

As members of a multidisciplinary team of professionals who treat children and adolescents with functional neurological (conversion) disorder (FND), we highlight the pressing need to develop an FND-informed culture of care that takes into account recent advances in our understanding of this group of patients. Stories of clinical encounters in health care settings from around the world-told by children and adolescents with FND, their parents, and health professionals-portray an outdated culture of care characterized by iatrogenic stigma, erosion of empathy and compassion within the clinician-patient relationship, and a lack of understanding of FND and its complex neurobiology. After a brief exploration of the outdated culture, we share our counterstories: how we and our colleagues have worked, and continue to work, to create an FND-informed culture in the health systems where we practice. We discuss the therapeutic use of child-friendly language. We also discuss a range of structural, educational, and process interventions that can be used to promote FND-informed beliefs and attitudes, FND-informed clinician-patient encounters, and FND-informed referral processes, treatment pathways, and therapeutic interventions

Scaling relation for determining the critical threshold for continuum percolation of overlapping discs of two sizes

We study continuum percolation of overlapping circular discs of two sizes. We propose a phenomenological scaling equation for the increase in the effective size of the larger discs due to the presence of the smaller discs. The critical percolation threshold as a function of the ratio of sizes of discs, for different values of the relative areal densities of two discs, can be described in terms of a scaling function of only one variable. The recent accurate Monte Carlo estimates of critical threshold by Quintanilla and Ziff [Phys. Rev. E, 76 051115 (2007)] are in very good agreement with the proposed scaling relation.Comment: 4 pages, 3 figure

Temperature and Field Dependence of the Mobility in Liquid-Crystalline Conjugated Polymer Films

The transport properties of organic light-emitting diodes in which the emissive layer is composed of conjugated polymers in the liquid-crystalline phase have been investigated. We have performed simulations of the current transient response to an illumination pulse via the Monte Carlo approach, and from the transit times we have extracted the mobility of the charge carriers as a function of both the electric field and the temperature. The transport properties of such films are different from their disordered counterparts, with charge carrier mobilities exhibiting only a weak dependence on both the electric field and temperature. We show that for spatially ordered polymer films, this weak dependence arises for thermal energy being comparable to the energetic disorder, due to the combined effect of the electrostatic and thermal energies. The inclusion of spatial disorder, on the other hand, does not alter the qualitative behaviour of the mobility, but results in decreasing its absolute value.Comment: 9 pages, 8 figures, submitted to Phys. Rev.

Localized and Delocalized Charge Transport in Single-Wall Carbon-Nanotube Mats

We measured the complex dielectric constant in mats of single-wall carbon-nanotubes between 2.7 K and 300 K up to 0.5 THz. The data are well understood in a Drude approach with a negligible temperature dependence of the plasma frequency (omega_p) and scattering time (tau) with an additional contribution of localized charges. The dielectric properties resemble those of the best ''metallic'' polypyrroles and polyanilines. The absence of metallic islands makes the mats a relevant piece in the puzzle of the interpretation of tau and omega_p in these polymers.Comment: 4 pages including 4 figure