5,896 research outputs found
The geomorphological setting of some of Scotland's east coast freshwater mills: a comment on Downward and Skinner (2005) ‘Working rivers: the geomorphological legacy...’
Many of the water mills on Scotland's east coast streams, unlike those discussed recently by Downward and Skinner (2005 Area 37 138–47), are found in predominantly bedrock reaches immediately downstream of knickpoints (i.e. bedrock steps). Bedrock knickpoints in the lower reaches of Scottish rivers are a widespread fluvial response to the glacio-isostatic rebound of northern Britain. These steps in the river profile propagate headward over time, but for intervals of a few centuries or so they are sufficiently stable to be exploited for the elevational fall necessary to power the mill wheel. Many of these mills were apparently powered by ‘run-of-the-river’, as are some today that formerly had mill dams. The typical lack of sediment storage along the erosional lower reaches of many Scottish rivers means that failure of mill structures in Scotland will probably have less dramatic geomorphological and management implications than those suggested by Downward and Skinner for southern English rivers
Implementation of the LDA+U method using the full potential linearized augmented plane wave basis
We provide a straightforward and efficient procedure to combine LDA+U total
energy functional with the full potential linearized augmented plane wave
method. A detailed derivation of the LDA+U Kohn-Sham type equations is
presented for the augmented plane wave basis set, and a simple
``second-variation'' based procedure for self-consistent LDA+U calculations is
given. The method is applied to calculate electronic structure and magnetic
properties of NiO and Gd. The magnetic moments and band eigenvalues obtained
are in very good quantitative agreement with previous full potential LMTO
calculations. We point out that LDA+U reduces the total d charge on Ni by 0.1
in NiO
Follow-up for breast cancer - the patients' view
Background: International and national guidelines (S3 guideline) for the surveillance of post-treatment breast cancer patients recommend a clinical follow-up including routine history and physical examination and regular mammograms. The practice of a clinical follow-up has been often discussed, but has been proven not to be inferior when compared to an intensified follow-up in randomized trials. Patients and Methods: The present manuscript reports the patients' view on the basis of a survey including 2000 patients with a history of breast cancer. Results: A total of 452 patients (22.6%) answered the questionnaire. The median age was 62 years (range 23-85 years). More than 80% of the patients were disease-free at the time of the survey. The need for surveillance was affirmed by the majority of patients (>95%), and one third stated that there was a need for more technical efforts during follow-up. In contrast to the follow-up guidelines, the results of the present survey indicated that most of the regularly scheduled follow-up visits were expanded using extensive laboratory and imaging procedures. Conclusion: This survey shows that the majority of physicians obviously do not accept the present follow-up guidelines. A new surveillance study investigating the efficacy of an intensified surveillance based on the improved possibilities of modern diagnostics and endocrine, immunotherapeutic, chemotherapeutic and interventional treatment options is warranted
Whole lifespan microscopic observation of budding yeast aging through a microfluidic dissection platform
Important insights into aging have been generated with the genetically tractable and short-lived budding yeast. However, it is still impossible today to continuously track cells by high-resolution microscopic imaging (e.g., fluorescent imaging) throughout their entire lifespan. Instead, the field still needs to rely on a 50-y-old laborious and time-consuming method to assess the lifespan of yeast cells and to isolate differentially aged cells for microscopic snapshots via manual dissection of daughter cells from the larger mother cell. Here, we are unique in achieving continuous and high-resolution microscopic imaging of the entire replicative lifespan of single yeast cells. Our microfluidic dissection platform features an optically prealigned single focal plane and an integrated array of soft elastomer-based micropads, used together to allow for trapping of mother cells, removal of daughter cells, monitoring gradual changes in aging, and unprecedented microscopic imaging of the whole aging process. Using the platform, we found remarkable age-associated changes in phenotypes (e.g., that cells can show strikingly differential cell and vacuole morphologies at the moment of their deaths), indicating substantial heterogeneity in cell aging and death. We envision the microfluidic dissection platform to become a major tool in aging research.
Nucleosomes in pancreatic cancer patients during radiochemotherapy
Nucleosomes appear spontaneously in elevated concentrations in the serum of patients with malignant diseases as well as during chemo- and radiotherapy. We analyzed whether their kinetics show typical characteristics during radiochemotherapy and enable an early estimation of therapy efficacy. We used the Cell Death Detection Elisaplus ( Roche Diagnostics) and investigated the course of nucleosomes in the serum of 32 patients with a local stage of pancreatic cancer who were treated with radiochemotherapy for several weeks. Ten of them received postsurgical therapy, 21 received primary therapy and 1 received therapy for local relapse. Blood was taken before the beginning of therapy, daily during the first week, once weekly during the following weeks and at the end of radiochemotherapy. The response to therapy was defined according to the kinetics of CA 19-9: a decrease of CA 19-9 650% after radiochemotherapy was considered as `remission'; an increase of >= 100% ( which was confirmed by two following values) was defined as `progression'. Patients with `stable disease' ranged intermediately. Most of the examined patients showed a decrease of the concentration of nucleosomes within 6 h after the first dose of radiation. Afterwards, nucleosome levels increased rapidly, reaching their maximum during the following days. Patients receiving postsurgery, primary or relapse therapies did not show significant differences in nucleosome values during the time of treatment. Single nucleosome values, measured at 6, 24 and 48 h after the application of therapy, could not discriminate significantly between patients with no progression and those with progression of disease. However, the area under the curve of the first 3 days, which integrated all variables of the initial therapeutic phase, showed a significant correlation with the progression-free interval ( p = 0.008). Our results indicate that the area under the curve of nucleosomes during the initial phase of radiochemotherapy could be valuable for the early prediction of the progression-free interval. Copyright (C) 2005 S. Karger AG, Basel
Quasiperiodic spin-orbit motion and spin tunes in storage rings
We present an in-depth analysis of the concept of spin precession frequency
for integrable orbital motion in storage rings. Spin motion on the periodic
closed orbit of a storage ring can be analyzed in terms of the Floquet theorem
for equations of motion with periodic parameters and a spin precession
frequency emerges in a Floquet exponent as an additional frequency of the
system. To define a spin precession frequency on nonperiodic synchro-betatron
orbits we exploit the important concept of quasiperiodicity. This allows a
generalization of the Floquet theorem so that a spin precession frequency can
be defined in this case too. This frequency appears in a Floquet-like exponent
as an additional frequency in the system in analogy with the case of motion on
the closed orbit. These circumstances lead naturally to the definition of the
uniform precession rate and a definition of spin tune. A spin tune is a uniform
precession rate obtained when certain conditions are fulfilled. Having defined
spin tune we define spin-orbit resonance on synchro--betatron orbits and
examine its consequences. We give conditions for the existence of uniform
precession rates and spin tunes (e.g. where small divisors are controlled by
applying a Diophantine condition) and illustrate the various aspects of our
description with several examples. The formalism also suggests the use of
spectral analysis to ``measure'' spin tune during computer simulations of spin
motion on synchro-betatron orbits.Comment: 62 pages, 1 figure. A slight extension of the published versio
The new small-angle neutron scattering instrument SANS-1 at MLZ—characterization and first results
AbstractA thorough characterization of the key features of the new small-angle neutron scattering instrument SANS-1 at MLZ, a joint project of Technische Universität München and Helmholtz Zentrum Geesthacht, is presented. Measurements of the neutron beam profile, divergency and flux are given for various positions along the instrument including the sample position, and agree well with Monte Carlo simulations of SANS-1 using the program McStas. Secondly, the polarization option of SANS-1 is characterized for a broad wavelength band. A key feature of SANS-1 is the large accessible Q-range facilitated by the sideways movement of the detector. Particular attention is hence paid to the effects that arise due to large scattering angles on the detector where a standard cos3 solid angle correction is no longer applicable. Finally the performance of the instrument is characterized by a set of standard samples
Theoretical Models of Sunspot Structure and Dynamics
Recent progress in theoretical modeling of a sunspot is reviewed. The
observed properties of umbral dots are well reproduced by realistic simulations
of magnetoconvection in a vertical, monolithic magnetic field. To understand
the penumbra, it is useful to distinguish between the inner penumbra, dominated
by bright filaments containing slender dark cores, and the outer penumbra, made
up of dark and bright filaments of comparable width with corresponding magnetic
fields differing in inclination by some 30 degrees and strong Evershed flows in
the dark filaments along nearly horizontal or downward-plunging magnetic
fields. The role of magnetic flux pumping in submerging magnetic flux in the
outer penumbra is examined through numerical experiments, and different
geometric models of the penumbral magnetic field are discussed in the light of
high-resolution observations. Recent, realistic numerical MHD simulations of an
entire sunspot have succeeded in reproducing the salient features of the
convective pattern in the umbra and the inner penumbra. The siphon-flow
mechanism still provides the best explanation of the Evershed flow,
particularly in the outer penumbra where it often consists of cool, supersonic
downflows.Comment: To appear in "Magnetic Coupling between the Interior and the
Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and
Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200
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