407 research outputs found
Electron Mobility in Dense Argon Gas at Several Temperatures
The mobility of excess electrons in dense Argon gas has been measured
as a function of the applied electric field and of the gas density N at
several temperatures in the range K, encompassing the critical
temperature Tc=150.86 K. We report here measurements at densities up to N?7
nm, close to the critical density, 8.1 nm, reached
for the isotherm closest to the critical one. At all temperatures, below as
well as above Tc, and up to moderately high densities, the density-normalized
mobility shows the usual electric field dependence present in a gas
with a Ramsauer-Townsend minimum due to the mainly attractive electron-atom
interaction. mN is constant and field independent for small values of
shows a maximum for a reduced field 4 mTd, and then decreases
rapidly with the field, approximately proportional to The
zero-field density-normalized mobility for all T> shows the
well known anomalous positive density effect, i.e., m0N increases with
increasing N, confirming previous results obtained for T=300 K and 162.7 K.
Below Tc, however, does not show the expected anomalous positive
density effect, but it rather features a broad maximum. This appears to be a
crossover behavior between the positive density effect shown for T>Tc and the
small negative effect previously observed for T 90 K. In any case, the
data at all temperatures confirm the interpretation of the anomalous density
effect as being essentially due by the density-dependent quantum shift of the
electron ground state kinetic energy in a disordered medium as a result of
multiple scattering (MS) processes, although other MS processes do influence
the outcome of the experiment.Comment: 8 Figures, submitted to IEEE-TDEI, October 200
A Framework for Promoting Diverse Perennial Circular Forage Systems for More Resilient Agricultural Landscapes: Developing Extension and Educational Tools for Resilience and Sustainability
The Resilience CAP Team seeks to use diverse, perennial, circular forage systems (DPCFS) to enhance biodiversity, improve soil and plant health, support ecosystem service, all towards achieving greater resilience to global change and improving the farm economy and quality of life. Our project will design a transdisciplinary framework that combines agronomic, ecological, economic, and sociological factors to achieve greater resilience and stability in agricultural systems through use of DPCFS. In this paper, we describe two of the project’s six objectives. Objective 5 is our extension/outreach arm where we will develop extension media, activities, and actionable decision tools to communicate concepts about the benefits of DPCFS to all stakeholders including farmers, consumers, lenders, and policy makers. To this end, our Extension Team is developing an interactive network of farmers, researchers, and other stakeholders that use multidirectional communication to help reduce barriers to forage use in production systems. Our network will be supported by traditional print and face-to-face approaches, a website, online programming, interactive online decision tools, and social media. Objective 6 is our education arm, where we will develop educational materials on the importance of resilience, ecosystem services, and economic value of DPCFS and integrate the materials into K-12 and university curricula. The activities are designed to develop knowledge and skills associated with sustainable agriculture, with emphasis on DPCFS. Currently, we seek to have multi-institutional internship and graduate seminar programs throughout the year
Injection of photoelectrons into dense argon gas
The injection of photoelectrons in a gaseous or liquid sample is a widespread
technique to produce a cold plasma in a weakly--ionized system in order to
study the transport properties of electrons in a dense gas or liquid. We report
here the experimental results of photoelectron injection into dense argon gas
at the temperatureT=142.6 K as a function of the externally applied electric
field and gas density. We show that the experimental data can be interpreted in
terms of the so called Young-Bradbury model only if multiple scattering effects
due to the dense environment are taken into account when computing the
scattering properties and the energetics of the electrons.Comment: 18 pages, 10 figures, figure nr. 10 has been redrawn, to be submitted
to Plasma Sources Science and Technolog
Multitemporal and Multispectral Remote Sensing of Soils in Cultured Landscapes of North Germany
Different techniques have been tested since 1974 to meet the difficult task of soil remote sensing in intensively cultured and small-parcelled landscapes of North Germany.
Conventional stereo - interpretation of physiographic elements and patterns of landscapes by pan, color and infrared air photographs lowers the necessary number of soil borings and the cost of survey appreciably as well as increasing the information content and accuracy of soil maps. Especially, man-induced soil erosion and accumulation of hilly young moraines, position of sand dunes and old river beds on outwash terraces and appearance of periglacial polygon soils on flattened old moraines, only partly or not detectable in the field, were made visible with remote sensing.
To increase the information content of remote sensing data and make interpretation more reproducible the multispectral remission was measured by an 11-channel-scanner. These data were calibrated by spectral photometry of soil samples within the wavelength range of 250 - 1400 nm to estimate by multiple regression analysis soil components, especially organic matter, free iron and clay.
Additional information was achieved by measuring three times a day the multitemporal thermal emission with the scanner in autumn and spring of test areas. The data were interpreted by experiments in the field and laboratory, which measured the heat balance of soils in relation to external factors and the soil moisture regime
FGFR2 amplification in colorectal adenocarcinoma
FGFR2 is recurrently amplified in 5% of gastric cancers and 1%–4% of breast cancers; however, this molecular alteration has never been reported in a primary colorectal cancer specimen. Preclinical studies indicate that several FGFR tyrosine-kinase inhibitors (TKIs), such as AZD4547, have in vitro activity against the FGFR2-amplified colorectal cell line, NCI-H716. The efficacy of these inhibitors is currently under investigation in clinical trials for breast and gastric cancer. Thus, better characterizing colorectal tumors for FGFR2 amplification could identify a subset of patients who may benefit from FGFR TKI therapies. Here, we describe a novel FGFR2 amplification identified by clinical next-generation sequencing in a primary colorectal cancer. Further characterization of the tumor by immunohistochemistry showed neuroendocrine differentiation, similar to the reported properties of the NCI-H716 cell line. These findings demonstrate that the spectrum of potentially clinically actionable mutations detected by targeted clinical sequencing panels is not limited to only single-nucleotide polymorphisms and insertions/deletions but also to copy-number alterations.</jats:p
Safety of Daptomycin in Patients Receiving Hemodialysis
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90386/1/phco.31.7.665.pd
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