140,733 research outputs found
A look at profiler performance
Since about 1974, Doppler radars operating in UHF and VHF ranges have been used increasingly to study atmospheric winds. Historically, large systems capable of obtaining data from high altitudes have focused attention on the mesosphere and stratosphere, rather than on the troposphere wherein abides most of the weather considered by most meteorologists. Research address some questions the meteorologist must logically ask first, viz., what is the actual performance capability of these systems, how accurate is the wind data of interest to meteorologists, and from what altitudes in the troposphere are the data reliably obtained
The transcription factor ATF5: role in cellular differentiation, stress responses, and cancer.
Activating transcription factor 5 (ATF5) is a cellular prosurvival transcription factor within the basic leucine zipper (bZip) family that is involved in cellular differentiation and promotes cellular adaptation to stress. Recent studies have characterized the oncogenic role of ATF5 in the development of several different types of cancer, notably glioblastoma. Preclinical assessment of a systemically deliverable dominant-negative ATF5 (dnATF5) biologic has found that targeting ATF5 results in tumor regression and tumor growth inhibition of glioblastoma xenografts in mouse models. In this review, we comprehensively and critically detail the current scientific literature on ATF5 in the context of cellular differentiation, survival, and response to stressors in normal tissues. Furthermore, we will discuss how the prosurvival role of ATF5 aides in cancer development, followed by current advances in targeting ATF5 using dominant-negative biologics, and perspectives on future research
Detection of laser-UV microirradiation-induced DNA photolesions by immunofluorescent staining
A low-power laser-UV microbeam of wave-length 257 nm was used for microirradiation of a small part of the nucleus of Chinese hamster cells. Following fixation in interphase or in the subsequent metaphase indirect immunofluorescent staining was performed with antiserum to photoproducts of DNA treated with far UV light.
The results show that antibodies specific for UV-irradiated DNA can be used for a direct detection of laser-UV microirradiation-induced DNA photolesions. The potential usefulness of this method for investigation of the spatial arrangement of chromosomes in the interphase nucleus is discussed
Mars high-resolution mapping
A series of photomosaics of high-resolution Viking Orbiter images of Mars is being prepared and published to support the Mars 1:500,000 scale geologic mapping program. More than 100 of these photomosaics were made manually, but for the last several years they have all been made digitally. The digital mosaics are published on the Mars Transverse Mercator (MTM) system, and they are also available to the appropriate principal investigators as digital files in the mosaicked digital image model (MDIM) format. The mosaics contain Viking Orbiter images with the highest available resolution: in some areas as high as 10 m/pixel. This resolution, where it exists, will support a 1:100,000 map scale. The full resolution of a mosaic is preserved in a digital file, but conventional lithographic publication of such large-scale inset maps will be done only if required by the geologic map author. When high-resolution images do not full the neatlines of an MTM quadrangle, the medium-resolution (1/256 degrees/pixel, or 231 m/pixel) MDIM is used. The mosaics are tied by image-matching to the planetwide MDIM, in which random errors as large as 5 km (10 mm at 1:500,000 scale) are common; a few much larger, worst-case errors also occur. Because of the distribution of the errors, many large discrepancies appear along the cutlines between frames with very different resolutions. Furthermore, each block of quadrangles is compiled on its own local control system, and adjacent blocks, compiled later, are unlikely to match. Selection of areas to be mapped is based on geologic mapping proposals reviewed and recommended by the Mars 1:500,000 scale geologic mapping review panel. There is no intention to map the entire planet at this scale
Non-singlet structure function of the 3He-3H system and divergence of the Gottfried integral
We study shadowing and antishadowing corrections to the flavor non-singlet
structure function F_2(3He)-F_2(3H) and show that the difference between the
one-particle density distributions of 3He and 3H plays an important role at
very small x. We find that the flavor non-singlet structure function in these
mirror nuclei is enhanced at small x by nuclear shadowing, which increases the
nuclear Gottfried integral, integrated from 10^{-4} to 1, by 11-36 %. When
integrated from zero, the Gottfried integral is divergent for these mirror
nuclei. It seems likely that, as a consequence of charge symmetry breaking,
this may also apply to the proton-neutron system.Comment: 29 pages, 6 figures, RevTe
Local Duality and Charge Symmetry Violation in Quark Distributions
We use local quark-hadron duality to calculate the nucleon structure function
as seen by neutrino and muon beams. Our result indicates a possible signal of
charge symmetry violation at the parton level in the very large x region.Comment: 4 pages, 2 figures. Modified version to appear on PRD. A dicussion on
the experimental errors of the form factors was adde
What Makes a Theory of Infinitesimals Useful? A View by Klein and Fraenkel
Felix Klein and Abraham Fraenkel each formulated a criterion for a theory of infinitesimals to be successful, in terms of the feasibility of implementation of the Mean Value Theorem. We explore the evolution of the idea over the past century, and the role of Abraham Robinson's framework therein
WTP vs.WTA: Christmas Presents and the Endowment Effect
Using data on the valuation of Christmas gifts received by students in different fields at a German university, we investigate whether the endowment effect differs between students of economics and other respondents and whether it varies with the market price of the object under consideration.Our estimation results suggest that economics students have both, a significant lower WTP andWTA, indicating that existing studies on the efficiency loss of holiday gifts and experimental studies on the endowment effect that rely on data from economics students may be biased. The result further indicate that the endowment effect is independent of the market price of the object.Loss aversion, endowment effect, Christmas presents, deadweight loss
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