930 research outputs found
Adjuvant chemotherapy for stage I non-seminomatous testicular cancer
Developments in the treatment of stage I testicular nonseminomatous germ cell tumours have aimed primarily at reducing morbidity since the introduction of retroperitoneal lymph node dissection. Surveillance after orchidectomy, i.e. follow-up alone with chemotherapy only for relapsed disease, was found to be logistically and psychologically taxing for patients. Risk factors for relapse were, however, identified from analyses of tumour histology of the orchidectomy specimen.Between September 1988 and April 1992, 20 patients with clinical stage I testicular non-seminomatous germ cell tumours and a relatively high risk of relapse were entered into a prospective study of adjuvant chemotherapy. The chemotherapy regimen consisted of 2 cycles of cisplatin, etoposide and bleomycin. Each cycle of chemotherapy lasted 3 days.There have been no relapses at a median follow-up of 31 months (range 12 - 53 months). Acute and late toxicity have been modest. We have found adjuvant chemotherapy to be effective after orchidectomy in patients with stage I disease with adverse prognostic factors for relapse
Atomic Binding Energies From a Modified Thomas-Fermi-Dirac Theory
A quantum correction of the statistical model of the atom was obtained by modifying March and Plaskett's region of integration in the (n/sub r/,l), or quantum-number, plane. Integrations over the plane lead, in the unmodified case, to the Thomas-Fermi density expression and energy equation. Integrations over the modified region are here shown to produce a modified Thomas-Fermi expression for the electron density, and a correction to the kinetic energy. The latter correction shows a similarity to the Weizsacker correction, but is smaller by a slowly changing factor of the order of 10. A modified Thomas-Fermi-Dirac equation was derived by the standard variational procedure. Numerical solutions of the equation were obtained, yielding atomic binding energies in much better agreement with experimental values than those of the unmodified theory. (auth
Preliminary Studies and Test Results of a Superconducting Hysteresis Motor with Multiphase Windings and Variable Number of Magnetic Poles
Part 15: Energy TransformationInternational audienceIn this paper a procedure for determining the number of different synchronous speeds that can be obtained from the stator of a drum motor as a function of the number of slots is presented. This preliminary study is foreseen for a hysteresis high-temperature superconducting motor, but the approach is directly applied in conventional motors. The targeted device has multiphase windings, in order to achieve full flexibility in torque-speed space through electronic variation of magnetic poles. Simulations are performed in order to achieve a qualitative understanding of the behaviour of the motor, namely in what concerns to torque and settling times from initial to synchronous speed. A prototype with eighteen slots in the stator and a bulk YBCO rotor is described and built, and experimental values of torque are obtained
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Information theoretic derivation of network architecture and learning algorithms
Using variational techniques, we derive a feedforward network architecture that minimizes a least squares cost function with the soft constraint that the mutual information between input and output be maximized. This permits optimum generalization for a given accuracy. A set of learning algorithms are also obtained. The network and learning algorithms are tested on a set of test problems which emphasize time series prediction. 6 refs., 1 fig
A Supersymmetric Effective Chiral Lagrangian
We construct in a manifestly supersymmetric form the leading and subleading
terms in momentum for an effective supersymmetric chiral Lagrangian in terms of
complex pions and their superpartners. A soft supersymmetry breaking term is
included and below the supersymmetry breaking scale the Lagrangian reduces to
the usual bosonic chiral Lagrangian in terms of real pions.Comment: University of Southampton preprint no. SHEP 93/94-12 LATE
The spectrum of D_s mesons from lattice QCD
The spectrum of orbitally excited mesons is computed in the continuum
limit of quenched lattice QCD. The results are consistent with the
interpretation that the narrow resonance in the channel discovered
by the BABAR Collaboration is a meson. Furthermore, within
statistical errors, the and the mass splittings are equal,
in agreement with the chiral multiplet structure predicted by heavy hadron
chiral effective theory. On our coarsest lattice we present results from the
first study of orbitally excited mesons with two flavors of dynamical
quarks, with mass slightly larger than the strange quark mass. These results
are consistent with the quenched data.Comment: 8 pages, 2 figure
Diquark-Antidiquark with open charm in QCD sum rules
Using the QCD sum rule approach we investigate the possible four-quark
structure of the recently observed charmed scalar mesons
(BELLE) and (FOCUS) and also of the very narrow
, firstly observed by BABAR. We use diquak-antidiquark
currents and work to the order of in full QCD, without relying on
expansion. Our results indicate that a four-quark structure is acceptable for
the resonances observed by BELLE and BABAR: and
respectively, but not for the resonances observed by FOCUS:
.Comment: 6 pages, 5 eps figures; Contribution to the 'Workshop on Light-Cone
QCD and Nonperturbative Hadron Physics 2005 (LC2005)', Cairns-Australi
Plasma polymerization of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl in a collisional, capacitively coupled radio frequency discharge
Plasma polymerization of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) yields thin films containing stable nitroxide radicals that have properties analogous to that of nitric oxide (NO) without short lifetimes. This property gives TEMPO films a wide variety of potential applications. Typically, control of the final film chemistry is difficult and the plasma discharge conditions must be tailored to in order to maximize the retention of these nitroxide groups during the polymerization and deposition process. In this study, plasma diagnostics and surface analysis of the deposited films were carried out to determine the optimal plasma conditions for the retention of nitroxide groups. These techniques included energy-resolved mass spectrometry, heated planar probe ion current measurements, deposition rate measurements, and x-ray photoelectron spectroscopy (XPS). Results show that operating the plasma with a combination of low input powers and high pressures produces a collisional discharge in which fragmentation of the TEMPO molecule is suppressed, leading to good retention of nitroxide groups. Ion energy distribution functions and quartz crystal microbalance measurements support the soft landing theory of ion deposition on the substrate within this γ-mode, in which the flux of low energy, soft landed ions form the primary contribution to film growth. XPS analysis of deposited polymers shows 75.7% retention of N - O groups in the polymer films deposited in a 25 Pa 5 W discharge. © 2020 Author(s)
Dark mammoth trunks in the merging galaxy NGC 1316 and a mechanism of cosmic double helices
NGC 1316 is a giant, elliptical galaxy containing a complex network of dark,
dust features. The morphology of these features has been examined in some
detail using a Hubble Space Telescope, Advanced Camera for Surveys image. It is
found that most of the features are constituted of long filaments. There also
exist a great number of dark structures protruding inwards from the filaments.
Many of these structures are strikingly similar to elephant trunks in H II
regions in the Milky Way Galaxy, although much larger. The structures, termed
mammoth trunks, generally are filamentary and often have shapes resembling the
letters V or Y. In some of the mammoth trunks the stem of the Y can be resolved
into two or more filaments, many of which showing signs of being intertwined. A
model of the mammoth trunks, related to a recent theory of elephant trunks, is
proposed. Based on magnetized filaments, the model is capable of giving an
account of the various shapes of the mammoth trunks observed, including the
twined structures.Comment: Accepted for publication in Astrophysics & Space Scienc
Level-Spacing Distributions and the Bessel Kernel
The level spacing distributions which arise when one rescales the Laguerre or
Jacobi ensembles of hermitian matrices is studied. These distributions are
expressible in terms of a Fredholm determinant of an integral operator whose
kernel is expressible in terms of Bessel functions of order . We derive
a system of partial differential equations associated with the logarithmic
derivative of this Fredholm determinant when the underlying domain is a union
of intervals. In the case of a single interval this Fredholm determinant is a
Painleve tau function.Comment: 18 pages, resubmitted to make postscript compatible, no changes to
manuscript conten
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