170,682 research outputs found
Cornelia Eichner
No full textc: Ramona Ahlers-Bergner Ausstellungstext „Heimat Heute?“ bevor du fehlst (für k.) wir sollten uns öfter mal umarmen, damit das leben nicht zerrinnt zwischen den tagen, an denen nur der rabe auf dem giebel uns widerspruch gibt. viel zu schnell fliegt er davon und lässt zurück ein leeres dach (ce’17) Lebensweg Cornelia Eichner wurde 1972 in Zwickau geboren und lebt mit zwei Kindern in Dresden. Sie absolvierte ein Fachschulstudium z..
IKFC - Instrument zur Kodierung des Führungsverhaltens im Coachinprozess
No full texteingereicht von Julia Carine Eichner & Larissa Sophia UnglertLiteraturverzeichnis: Seite 60-65 und Seite 43-46Im Anhang der Masterarbeit befindet sich ein weiteres Werk (überarbeitete Seminararbeit): IKFC - Instrument zur Kodierung des Führungsverhaltens im Coachingprozess : Manual / Julia C. Eichner und Larissa S. UnlertMasterarbeit Paris Lodron Universität Salzburg 2019Abstract in deutscher und englischer Sprach
Internal structure of the fly elementary motion detector
Full text linkFlies use visual motion information for flight control, stabilization and object tracking. However, information about local motion such as direction and velocity is not explicitly represented at the level of the retina but must be computed by subsequent motion detection circuitry. The output of these circuits can be recorded in large, direction-selective lobula plate tangential cells,
that integrate over hundreds of elementary motion detectors. The computational structure of these detectors is best described by the Reichardt model, where the signals from two neighboring photoreceptors become multiplied after one of them has been delayed. However, the neural correlate of the Reichardt Detector, i.e. the identity, physiology and connectivity of the constituting cells, has escaped further characterization due to technical difficulties in recording from these small neurons.
In this thesis, I investigated the internal structure of the fly motion detection circuit by a combination of electrophysiology, computer simulations and mathematical modeling. First, I studied the effect of the mean luminance on motion detection. I found that the response strength of lobula plate tangential cells strongly depends on stimulus contrast but barely changes as a function of mean luminance. Adaptation to a new mean luminance follows an exponential decay with a time constant of several hundred milliseconds. I next investigated the structural consequences of splitting the visual input into ON and OFF components, as recently discovered in the fruit fly. The original Reichardt Detector can be refined by incorporating these findings, giving rise to two alternative structures. The 4-Quadrant-Detector consists of four independent subunits of the Reichardt type, correlating ON with ON, OFF with OFF, ON with OFF and OFF with ON signals. In contrast, the 2-Quadrant-Detector consists of two subunits only, that
correlate ON with ON and OFF with OFF signals. In order to distinguish between these two models, I first stimulated
flies with apparent motion stimuli consisting of a sequence of two brightness steps at neighboring locations, while recording the motion detector output in lobula plate tangential cells of the blow fly. I found strongly direction-selective responses to ON-ON and OFF-OFF sequences, but also to ON-OFF and OFF-ON sequences. At first sight, these results seem to support the 4-Quadrant-Detector. However, I showed with simulations and an analytical treatment that the 2-Quadrant-Detector, when equipped with an appropriate preprocessing stage, is capable of reproducing such responses as well. Based on predictions from model simulations, I designed a new stimulus protocol consisting of a sequence of short brightness pulses instead of steps. For such stimuli, the 2-Quadrant-Detector does not produce significant responses to ON-OFF and OFF-ON sequences, in contrast to the 4-Quadrant-Detector. The corresponding recordings cannot be reconciled with the 4-Quadrant-Detector but are in good
agreement with the 2-Quadrant-Detector.
I therefore conclude that the internal structure of the
y elementary motion detector consists of two non-interacting subunits for detecting ON and OFF motion, respectively. These results mark an important step in the ongoing dissection of the insect motion detection circuit
by providing an updated model that better matches the structure and physiology of the corresponding neural hardware
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Carolyn J. Eichner, The Paris Commune. A Brief History, New Brunswick, Rutgers University Press, 2022, 143p. (=Reinventions of the Paris Commune, 1), ISBN 978-1-9788-2768-4
No full textMarion C. Carolyn J. Eichner, The Paris Commune. A Brief History, New Brunswick, Rutgers University Press, 2022, 143p. (=Reinventions of the Paris Commune, 1), ISBN 978-1-9788-2768-4 . Francia Recensio. 2022;2022(4)
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
Does growth rate affect diatom compositional response to temperature?
No full textTemperature is one of the environmental factors that most strongly influence the life of microalgae, from the enzymatic level up to the modification of biosynthetic and degradation potential and, thus, cellular composition. When exposed to a change in environmental milieu two main responses can be attained by cells: acclimation or homoeostasis. Recent studies testing the impact of other environmental factors indicated that the choice between these strategies is related to growth rates, i.e. cells dividing at a faster rate showed inclination to acclimation while cells dividing at a slower rate were more prone to homoeostasis. These findings motivated us to further explore the extent to which these compositional response modes are applied under varying temperature. Two representative marine diatoms, one centric, Thalassiosira pseudonana, and one pennate, Cylindrotheca fusiformis were investigated. Species were cultured at 15°C, 20°C and 30°C and at two growth rates. Compositional response was analysed with respect to elemental stoichiometry (carbon, nitrogen, silica, phosphorus, sulphur, manganese, iron, zinc and copper) and the major organic pool ratios (carbohydrate:lipid, carbohydrate:protein and protein:lipid). While T. pseudonana exhibited an acclimation response to temperature, C. fusiformis proved to be strongly homoeostatic. In the case of T. pseudonana, our data showed that the variations in composition were consistent with the growth rate dependence hypothesis for many micronutrients, but not for carbon and nitrogen contents, and C:N ratio. These species-specific differences in response mode highlight the diversity in ecophysiological strategies of diatoms, which needs to be considered when predicting climate change responses
Golden gravitational lensing systems from the Sloan Lens ACS Survey. I. SDSS J1538+5817 : one lens for two sources
No full textWe present a gravitational lensing and photometric study of the exceptional strong lensing system SDSS J1538+5817, identified by the Sloan Lens Advanced Camera for Survey. The lens is a luminous elliptical galaxy at redshift zl = 0.143. Using Hubble Space Telescope public images obtained with two different filters, the presence of two background sources lensed, respectively, into an Einstein ring and a double system is ascertained. Our new spectroscopic observations, performed at the Nordic Optical Telescope, reveal unequivocally that the two sources are located at the same redshift zs = 0.531. We investigate the total (luminous and dark) mass distribution of the lens between 1 and 4 kpc from the galaxy center by means of parametric and non-parametric lensing codes that describe the multiple images as point-like objects. Bootstrapping and Bayesian analyses are performed to determine the uncertainties on the quantities relevant to the lens mass characterization. Several disparate lensing models provide results that are consistent, given the errors, with those obtained from the best-fit model of the lens mass distribution in terms of a singular power-law ellipsoid model. In particular, the lensing models agree on: (1) reproducing accurately the observed positions of the images; (2) predicting a nearly axisymmetric total mass distribution, centered and oriented as the light distribution; (3) measuring a value of 8.11+0.27 –0.59 × 1010 M sun for the total mass projected within the Einstein radius of 2.5 kpc; and (4) estimating a total mass density profile slightly steeper than an isothermal one . A fit of the Sloan Digital Sky Survey multicolor photometry with composite stellar population models provides a value of 20+1 –4 × 1010 M sun for the total mass of the galaxy in the form of stars and of 0.9+0.1 –0.2 for the fraction of projected luminous over total mass enclosed inside the Einstein radius. By combining lensing (total) and photometric (luminous) mass measurements, we differentiate the lens mass content in terms of luminous and dark matter components. This two-component modeling, which is viable only in extraordinary systems like SDSS J1538+5817, leads to a description of the global properties of the galaxy dark matter halo. Extending these results to a larger number of lens galaxies would considerably improve our understanding of galaxy formation and evolution processes in the ΛCDM scenario
- …
