171,457 research outputs found
Towards high-energy neutrino astronomy
No full textThe search for the sources of cosmic rays is a three-fold assault, using charged cosmic
rays, gamma rays and neutrinos. The first conceptual ideas to detect high energy neutrinos
date back to the late fifties. The long evolution towards detectors with a realistic
discovery potential started in the seventies and eighties, with the pioneering works in
the Pacific Ocean close to Hawaii and in Lake Baikal in Siberia. But only now, half a
century after the first concepts, such a detector is in operation: IceCube at the South
Pole. We do not yet know whether with IceCube we will indeed detect extraterrestrial high
energy neutrinos or whether this will remain the privilege of next generation telescopes.
But whatever the answer will be: the path to the present detectors was a remarkable
journey. This review sketches its main milestones
Binding Kinetics of Bisintercalator Triostin A with Optical Tweezers Force Mechanics
No full textKleimann C, Sischka A, Spiering A, et al. Binding Kinetics of Bisintercalator Triostin A with Optical Tweezers Force Mechanics. Biophysical Journal. 2009;97(10):2780-2784.The binding kinetics of the intercalative binding of Triostin A to A-DNA was investigated by measuring the force extension response of the DNA-ligand complexes with an optical tweezers system. These force response curves, containing the information about different binding properties, were analyzed based on a recent method (put forth by another research group) for monointercalators that was extended to bisintercalators. Our binding analysis reveals an exponential dependence of the association constant on the applied external force as well as a decreasing binding site size. In general, our results are in agreement with those for the monointercalator ethidium. However, to explain the high-force binding site size, a new model for bisintercalation of Triostin A at high forces is proposed
Development of a goniometer stage for single crystal Mössbauer measurements
No full textAbstract 3.10.f
Advances in Mössbauer Emission-Spectroscopy
No full textSpiering H, Alflen M, Gütlich P, et al. Advances in Mössbauer Emission-Spectroscopy. HYPERFINE INTERACTIONS. 1990;53(1-4):113-141
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Evidence for IHA migration during axial rotation of a lumbar spine segment by using a novel high-resolution 6D kinematic tracking system
No full textThe biomechanical properties of the lumbar spine have long been studied. However, despite its enormous importance, basic functional and morphological properties have been not well understood and require further experimental analysis since data concerning the spatial instantaneous segmental motions are hardly available. This study describes the theoretical background and the technical properties of an innovative method for tracking the instantaneous 3D motion of human spinal segments in vitro at high spatial resolution. This new acquisition system allows to scrutinise closely the location and alignment of the segmental instantaneous helical axis (IHA) and the respective screw pitch as functions of the absolute rotational angle. The required precision of the measuring device was attained (a) by six highly resolving linear inductive displacement sensors in a special spatially configuration (3-2-1), (b) by a method to apply torque and force independently of each other without counteraction, and (c) by suppression of vibrations. The validity and reliability of the experimental set-up and the numerical method of data analysis were tested by subjects of known mechanical properties. In vitro experiments with a human lumbar segment (L3/L4, autopsy material) demonstrated that (a) the IHA migrated during axial rotation from one segmental articulatio zygapophysialis to the other joint, (b) the IHA tilted medial-laterally, and (c) the pitch of the screw altered linearly as a function of the rotational angle. This phenomenon is traced back to the guidance of the articluationes zygapophysiales. The validation of the method allows to map segments of the entire vertebral column. The results can be used as benchmarks for future models of the human spine. (C) 2003 Elsevier Ltd. All rights reserved
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
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