5,679 research outputs found
Automorphisms of the affine SU(3) fusion rules
We classify the automorphisms of the (chiral) level-k affine SU(3) fusion
rules, for any value of k, by looking for all permutations that commute with
the modular matrices S and T. This can be done by using the arithmetic of the
cyclotomic extensions where the problem is naturally posed. When k is divisible
by 3, the automorphism group (Z_2) is generated by the charge conjugation C. If
k is not divisible by 3, the automorphism group (Z_2 x Z_2) is generated by C
and the Altsch\"uler--Lacki--Zaugg automorphism. Although the combinatorial
analysis can become more involved, the techniques used here for SU(3) can be
applied to other algebras.Comment: 21 pages, plain TeX, DIAS-STP-92-4
Time-resolved charge detection in graphene quantum dots
We present real-time detection measurements of electron tunneling in a
graphene quantum dot. By counting single electron charging events on the dot,
the tunneling process in a graphene constriction and the role of localized
states are studied in detail. In the regime of low charge detector bias we see
only a single time-dependent process in the tunneling rate which can be modeled
using a Fermi-broadened energy distribution of the carriers in the lead. We
find a non-monotonic gate dependence of the tunneling coupling attributed to
the formation of localized states in the constriction. Increasing the detector
bias above 2 mV results in an increase of the dot-lead transition rate related
to back-action of the charge detector current on the dot.Comment: 8 pages, 6 figure
A neutron scattering study of the interplay between structure and magnetism in Ba(FeCo)As
Single crystal neutron diffraction is used to investigate the magnetic and
structural phase diagram of the electron doped superconductor
Ba(FeCo)As. Heat capacity and resistivity measurements have
demonstrated that Co doping this system splits the combined antiferromagnetic
and structural transition present in BaFeAs into two distinct
transitions. For =0.025, we find that the upper transition is between the
high-temperature tetragonal and low-temperature orthorhombic structures with
( K) and the antiferromagnetic transition occurs at
K. We find that doping rapidly suppresses the
antiferromagnetism, with antiferromagnetic order disappearing at . However, there is a region of co-existence of antiferromagnetism and
superconductivity. The effect of the antiferromagnetic transition can be seen
in the temperature dependence of the structural Bragg peaks from both neutron
scattering and x-ray diffraction. We infer from this that there is strong
coupling between the antiferromagnetism and the crystal lattice
Scintillating double beta decay bolometers
We present the results obtained in the development of scintillating Double
Beta Decay bolometers. Several Mo and Cd based crystals were tested with the
bolometric technique. The scintillation light was measured through a second
independent bolometer. A 140 g CdWO_4 crystal was run in a 417 h live time
measurement. Thanks to the scintillation light, the alpha background is easily
discriminated resulting in zero counts above the 2615 keV gamma line of
Thallium 208. These results, combined with an extremely easy light detector
operation, represent the first tangible proof demonstrating the feasibility of
this kind of technique.Comment: 15 pages, 8 figure
Large area Si low-temperature light detectors with Neganov-Luke effect
Next generation calorimetric experiments for the search of rare events rely
on the detection of tiny amounts of light (of the order of 20 optical photons)
to discriminate and reduce background sources and improve sensitivity.
Calorimetric detectors are the simplest solution for photon detection at
cryogenic (mK) temperatures. The development of silicon based light detectors
with enhanced performance thanks to the use of the Neganov-Luke effect is
described. The aim of this research line is the production of high performance
detectors with industrial-grade reproducibility and reliability.Comment: 4 pages, 2 figure
EU-NICE, Eurasian University Network for International Cooperation in Earthquakes
Despite the remarkable scientific advancements of earthquake engineering and seismology in many countries,
seismic risk is still growing at a high rate in the world’s most vulnerable communities. Successful practices have shown that a community’s capacity to manage and reduce its seismic risk relies on capitalization on policies, on
technology and research results. An important role is played by education, than contribute to strengthening
technical curricula of future practitioners and researchers through university and higher education programmes.
In recent years an increasing number of initiatives have been launched in this field at the international and global
cooperation level. Cooperative international academic research and training is key to reducing the gap between
advanced and more vulnerable regions. EU-NICE is a European Commission funded higher education
partnership for international development cooperation with the objective to build capacity of individuals who
will operate at institutions located in seismic prone Asian Countries. The project involves five European
Universities, eight Asian universities and four associations and NGOs active in advanced research on seismic
mitigation, disaster risk management and international development.
The project consists of a comprehensive mobility scheme open to nationals from Afghanistan, Bangladesh,
China, Nepal, Pakistan, Thailand, Bhutan, India, Indonesia, Malaysia, Maldives, North Korea, Philippines, and
Sri Lanka who plan to enrol in school or conduct research at one of five European partner universities in Italy,
Greece and Portugal. During the 2010-14 time span a total number of 104 mobilities are being involved in
scientific activities at the undergraduate, masters, PhD, postdoctoral and academic-staff exchange levels.
This high number of mobilities and activities is selected and designed so as to produce an overall increase of
knowledge that can result in an impact on earthquake mitigation. Researchers, future policymakers and
practitioners build up their curricula over a range of disciplines in the fields of engineering, seismology, disaster
risk management and urban planning. Specific educational and research activities focus on earthquake risk
mitigation related topics such as: anti-seismic structural design, structural engineering, advanced computer
structural collapse analysis, seismology, experimental laboratory studies, international and development issues in
disaster risk management, social-economical impact studies, international relations and conflict resolution
Searches for axioelectric effect of solar axions with BGO-scintillator and BGO-bolometer detectors
A search for axioelectric absorption of 5.5 MeV solar axions produced in the
reaction has been
performed with a BGO detectors. A model-independent limit on the product of
axion-nucleon and axion-electron coupling constants has
been obtained: for 90\% C.L..Comment: 5 pages, 3 figures, Proceedings of the 10th Patras Workshop on
Axions, WIMPs and WISP 29 June - 4 July 2014, CERN, Geneva, Switzerlan
Intravesical oxybutynin: mode of action assessed by passive diffusion and electromotive administration with pharmacokinetics of oxybutynin and N-desethyl oxybutynin.
PURPOSE: A proportion of patients with detrusor hyperreflexia who are unresponsive to oral oxybutynin often benefit from intravesical oxybutynin instillation. To our knowledge the precise mode of action of this method is obscure.
MATERIALS AND METHODS: In 12 patients with detrusor hyperreflexia who were previously unresponsive to oral and intravesical passive diffusion of 5 mg. oxybutynin we administered 5 mg. oxybutynin orally as well as increased doses of 15 mg. oxybutynin intravesically with passive diffusion and with 15 mA. associated electric current. Each administration mode per patient was associated with an 8-hour urodynamic monitoring session during which oxybutynin and N-desethyl oxybutynin plasma levels, and intravesical oxybutynin uptake were measured.
RESULTS: A dose of 5 mg. oxybutynin orally induced no urodynamic improvement with an area under the plasma concentration time curve of combined N-desethyl oxybutynin plus oxybutynin of 16,297 ng./8 hours and an area under the curve ratio of N-desethyl oxybutynin-to-oxybutynin of 11:1. Passive diffusion oxybutynin resulted in 12 mg. oxybutynin intravesical uptake and significant improvement in 3 of 8 urodynamic measurements, although the area under the curve of combined N-desethyl oxybutynin plus oxybutynin was only 2,123 ng./8 hours and the N-desethyl oxybutynin-to-oxybutynin ratio was 1.1:1.0. Electromotive administration of oxybutynin resulted in almost complete intravesical uptake of the 15 mg. dose, significant improvement in all 8 urodynamic measurements and an increased oxybutynin level versus oral and passive diffusion, although the area under the curve of combined N-desethyl oxybutynin plus oxybutynin was 4,574 ng./8 hours and the N-desethyl oxybutynin-to-oxybutynin ratio was inverted at 1.0:1.4. The oral dose of 5 mg. oxybutynin caused anticholinergic side effects in 8 of the 12 patients. Neither intravesical passive diffusion nor electromotive administration caused side effects with an uptake of 12 and 15 mg., respectively.
CONCLUSIONS: A large proportion of intravesical oxybutynin is sequestered, probably in the urothelium. Intravesical oxybutynin administration confers therapeutic benefits via localized direct action within the bladder wall.
Comment in
Intravesical treatment of bladder dysfunction. [J Urol. 2001
Intravesical electromotive mitomycin C versus passive transport mitomycin C for high risk superficial bladder cancer: a prospective randomized study.
PURPOSE: In laboratory studies electromotive mitomycin C (MMC) demonstrated markedly increased transport rates compared with passive transport. We performed a prospective study in patients with high risk superficial bladder cancer to assess the efficacy of intravesical electromotive vs passive MMC using bacillus Calmette-Guerin (BCG) as a comparative treatment.
MATERIALS AND METHODS: Following transurethral resection and multiple biopsies 108 patients with multifocal Tis, including 98 with T1 tumors, were randomized into 3 equal groups of 36 each who underwent 40 mg electromotive MMC instillation with 20 mA electric current for 30 minutes, 40 mg passive MMC with a dwell time of 60 minutes or 81 mg BCG with a dwell time of 120 minutes. Patients were scheduled for an initial 6 weekly treatments, a further 6 weekly treatments for nonresponders and a followup 10 monthly treatments for responders. Primary end points were the complete response rate at 3 and 6 months. MMC pharmacokinetics were assessed.
RESULTS: The complete response for electromotive vs passive MMC at 3 and 6 months was 53% versus 28% (p = 0.036) and 58% versus 31% (p = 0.012). For BCG the responses were 56% and 64%. Median time to recurrence was 35 vs 19.5 months (p = 0.013) and for BCG it was 26 months. Peak plasma MMC was significantly higher following electromotive MMC than after MMC (43 vs 8 ng/ml), consistent with bladder content absorption.
CONCLUSIONS: Intravesical electromotive administration increases bladder uptake of MMC, resulting in an improved response rate in cases of high risk superficial bladder cancer
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