349 research outputs found
Resolved sidebands in a strain-coupled hybrid spin-oscillator system
We report on single electronic spins coupled to the motion of mechanical
resonators by a novel mechanism based on crystal strain. Our device consists of
single-crystalline diamond cantilevers with embedded Nitrogen-Vacancy center
spins. Using optically detected electron spin resonance, we determine the
unknown spin-strain coupling constants and demonstrate that our system resides
well within the resolved sideband regime. We realize coupling strengths
exceeding ten MHz under mechanical driving and show that our system has the
potential to reach strong coupling. Our novel hybrid system forms a resource
for future experiments on spin-based cantilever cooling and coherent
spin-oscillator coupling.Comment: 4 pages, 4 figures and supplementary information. Comments welcome.
Further information under http://www.quantum-sensing.physik.unibas.ch
A short proof of the G\"ottsche conjecture
We prove that for a sufficiently ample line bundle on a surface , the
number of -nodal curves in a general -dimensional linear system
is given by a universal polynomial of degree in the four numbers
and .
The technique is a study of Hilbert schemes of points on curves on a surface,
using the BPS calculus of [PT3] and the computation of tautological integrals
on Hilbert schemes by Ellingsrud, G\"ottsche and Lehn.
We are also able to weaken the ampleness required, from G\"ottsche's
-very ample to -very ample.Comment: 8 pages. Published versio
A standardised method for measuring in situ denitrification in shallow aquifers: numerical validation and measurements in riparian wetlands
A tracer test to examine in situ denitrification in shallow groundwater by a piezometer with a packer system used bromide as a tracer of dilution and acetylene (10%) to block the denitrification process at the nitrous oxide stage. During the test, dissolved oxygen, nitrate (NO3-), bromide (Br-), nitrous oxide (N2O) and dissolved organic carbon (DOC) were measured. To calibrate the experimental method, comparison with numerical simulations of the groundwater transfer were carried out, taking into account the environmental characteristics. The method was tested by measurements undertaken in different environmental conditions (geology, land use and hydrology) in two riparian wetlands. Denitrification rates measured by this method ranged from 5.7 10-6 g N-NO3-L-1 h-1 to 1.97 10-3 g N-NO3-L-1 h-1 The method is applicable in shallow aquifers with a permeability from 10-2 to 10-4m s-1
Rank one discrete valuations of power series fields
In this paper we study the rank one discrete valuations of the field
whose center in k\lcor\X\rcor is the maximal ideal. In
sections 2 to 6 we give a construction of a system of parametric equations
describing such valuations. This amounts to finding a parameter and a field of
coefficients. We devote section 2 to finding an element of value 1, that is, a
parameter. The field of coefficients is the residue field of the valuation, and
it is given in section 5.
The constructions given in these sections are not effective in the general
case, because we need either to use the Zorn's lemma or to know explicitly a
section of the natural homomorphism R_v\to\d between the ring and
the residue field of the valuation .
However, as a consequence of this construction, in section 7, we prove that
k((\X)) can be embedded into a field L((\Y)), where is an algebraic
extension of and the {\em ``extended valuation'' is as close as possible to
the usual order function}
The effect of inelastic processes on tunneling
We study an electron that interacts with phonons or other linear or nonlinear
excitations as it resonantly tunnels. The method we use is based on mapping a
many-body problem in a large variational space exactly onto a one-body problem.
The method is conceptually simpler than previous Green's function approaches,
and allows the essentially exact numerical solution of much more general
problems. We solve tunneling problems with transverse channels, multiple sites
coupled to phonons, and multiple phonon degrees of freedom and excitations.Comment: 12 pages, REVTex, 4 figures in compressed tar .ps forma
Strong Discontinuities in the Complex Photonic Band Structure of Transmission Metallic Gratings
Complex photonic band structures (CPBS) of transmission metallic gratings
with rectangular slits are shown to exhibit strong discontinuities that are not
evidenced in the usual energetic band structures. These discontinuities are
located on Wood's anomalies and reveal unambiguously two different types of
resonances, which are identified as horizontal and vertical surface-plasmon
resonances. Spectral position and width of peaks in the transmission spectrum
can be directly extracted from CPBS for both kinds of resonances.Comment: 4 pages, 4 figures, REVTeX version
Singularities and Topology of Meromorphic Functions
We present several aspects of the "topology of meromorphic functions", which
we conceive as a general theory which includes the topology of holomorphic
functions, the topology of pencils on quasi-projective spaces and the topology
of polynomial functions.Comment: 21 pages, 1 figur
Scanning probe method for mapping the intensity and emission spectrum of semiconductor laser structures
В работе предложен зондовый метод, позволяющий визуализировать области выхода излучения из поверхности сколотых полупроводниковых лазеров с субволновым разрешением. Метод основан на детектировании в вакуумных условиях сдвига резонансной частоты зонда, связанной с нагревом балки либо кончика зонда излучением.Scanning probe method is proposed that allows to visualize regions of light emission on the cleavage surface of semiconductor lasers with a subwavelength resolution. The method is based on detecting under vacuum conditions of a shift in the resonant frequency of the probe related with the cantilever or probe tip heating by laser radiation
Application of an original RT-PCR–ELISA multiplex assay for MDR1 and MRP, along with p53 determination in node-positive breast cancer patients
The long-term prognostic value of tumoural MDR1 and MRP, along with p53 and other classical parameters, was analysed on 85 node-positive breast cancer patients receiving anthracycline-based adjuvant therapy. All patients underwent tumour resection plus irradiation and adjuvant chemotherapy (the majority receiving fluorouracil–epirubicin–cyclophosphamide). Median follow-up for the 54 alive patients was 7.8 years. Mean age was 53.7 years (range 28–79) and 54 patients were post-menopausal. MDR1 and MRP expression were quantified according to an original reverse transcription polymerase chain reaction multiplex assay with colourimetric enzyme-linked immunosorbent assay detection(β2-microglobulin as control). P53 protein was analysed using an immunoluminometric assay (Sangtec). MDR1 expression varied within an 11-fold range (mean 94, median 83), MRP within a 45-fold range (mean 315, median 242) and p53 protein from the limit of detection (0.002 ng mg−1) up to 35.71 ng mg−1(mean 1.18, median 0.13 ng mg−1). P53 protein was significantly higher in oestrogen receptor (ER)-negative than in ER-positive tumours (P = 0.039). The higher the p53, the lower the MDR1 expression (P = 0.015, r = –0.27). P53 was not linked to progesterone receptor (PR) status, S phase fraction, or MRP. Significantly greater MDR1 expression was observed in grade I tumours (P = 0.029). No relationship was observed between MDR1 and MRP. Neither MDR1 nor MRP was linked to ER or PR status. Unlike MDR1, MRP was correlated with the S phase: the greater the MRP, the lower the S phase (P = 0.006, r = –0.42). Univariate Cox analyses revealed that MDR1, MRP, p53 and S phase had no significant influence on progression-free or specific survival. A tendency suggested that the greater the p53, the shorter the progression-free survival (P = 0.076 as continuous and 0.069 as dichotomous). © 2000 Cancer Research Campaig
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