Dissociative paraplegia after epidural anesthesia: A case report

10.1186/1752-1947-7-56Journal of Medical Case Reports7

The RHESSI Microflare Height Distribution

We present the first in-depth statistical survey of flare source heights observed by RHESSI. Flares were found using a flare-finding algorithm designed to search the 6-10 keV count-rate when RHESSI's full sensitivity was available in order to find the smallest events (Christe et al., 2008). Between March 2002 and March 2007, a total of 25,006 events were found. Source locations were determined in the 4-10 keV, 10-15 keV, and 15-30 keV energy ranges for each event. In order to extract the height distribution from the observed projected source positions, a forward-fit model was developed with an assumed source height distribution where height is measured from the photosphere. We find that the best flare height distribution is given by g(h) \propto exp(-h/{\lambda}) where {\lambda} = 6.1\pm0.3 Mm is the scale height. A power-law height distribution with a negative power-law index, {\gamma} = 3.1 \pm 0.1 is also consistent with the data. Interpreted as thermal loop top sources, these heights are compared to loops generated by a potential field model (PFSS). The measured flare heights distribution are found to be much steeper than the potential field loop height distribution which may be a signature of the flare energization process

Hydrodynamic Approach to Vortex Lifetime in Trapped Bose Condensates

We study a vortex in a two-dimensional, harmonically trapped Bose-Einstein condensate at zero temperature. Through a variational calculation using a trial condensate wave function and a nonlinear Schroedinger Lagrangian, we obtain the effective potential experienced by a vortex at an arbitrary position in the condensate, and find that an off-center vortex will move in a circular trajectory around the trap center. We find the frequency of this precession to be smaller than the elementary excitation frequencies in the cloud. We also study the radiation of sound from a moving vortex in an infinite, uniform system, and discuss the validity of this as an approximation for the trapped case. Furthermore, we estimate the lifetime of a vortex due to imperfections in the trapping potential.Comment: 10 pages, 1 eps figure, submitted to PRA, adjustments in response to referee, one refernce adde

Strategies for the evolution of sex

We find that the hypothesis made by Jan, Stauffer and Moseley [Theory in Biosc., 119, 166 (2000)] for the evolution of sex, namely a strategy devised to escape extinction due to too many deleterious mutations, is sufficient but not necessary for the successful evolution of a steady state population of sexual individuals within a finite population. Simply allowing for a finite probability for conversion to sex in each generation also gives rise to a stable sexual population, in the presence of an upper limit on the number of deleterious mutations per individual. For large values of this probability, we find a phase transition to an intermittent, multi-stable regime. On the other hand, in the limit of extremely slow drive, another transition takes place to a different steady state distribution, with fewer deleterious mutations within the asexual population.Comment: RevTeX, 11 pages, multicolumn, including 12 figure

Statistical Survey of Type III Radio Bursts at Long Wavelengths Observed by the Solar TErrestrial RElations Observatory (STEREO)/Waves Instruments: Radio Flux Density Variations with Frequency

We have performed a statistical study of $152$ Type III radio bursts observed by Solar TErrestrial RElations Observatory (STEREO)/Waves between May 2007 and February 2013. We have investigated the flux density between $125$kHz and $16$MHz. Both high- and low-frequency cutoffs have been observed in $60\,$ of events suggesting an important role of propagation. As already reported by previous authors, we observed that the maximum flux density occurs at $1$MHz on both spacecraft. We have developed a simplified analytical model of the flux density as a function of radial distance and compared it to the STEREO/Waves data.Comment: published in Solar Physic

Combining geometric edge detectors for feature detection

We propose a novel framework for the analysis and modeling of discrete edge filters, based on the notion of signed rays. This framework will allow us to easily deduce the geometric and localization properties of a family of first-order filters, and use this information to design custom filter banks for specific applications. As an example, a set of angle-selective corner detectors is constructed for the detection of buildings in video sequences. This clearly illustrates the merit of the theory for solving practical recognition problems

Development of core outcome sets for studies relating to awareness and clinical management of reduced fetal movement

Objective: This study aimed to create core outcome sets (COSs) for use in research studies relating to the awareness and clinical management of reduced fetal movement (RFM). Design: Delphi survey and consensus process. Setting: International. Population: A total of 128 participants (40 parents, 19 researchers and 65 clinicians) from 16 countries. Methods: A systematic literature review was conducted to identify outcomes in studies of interventions relating to the awareness and the clinical management of RFM. Using these outcomes as a preliminary list, stakeholders rated the importance of these outcomes for inclusion in COSs for studies of: (i) awareness of RFM; and (ii) clinical management of RFM. Main outcome measures: Preliminary lists of outcomes were discussed at consensus meetings where two COSs (one for studies of RFM awareness and one for studies of clinical management of RFM). Results: The first round of the Delphi survey was completed by 128 participants, 66% of whom (n = 84) completed all three rounds. Fifty outcomes identified by the systematic review, after multiple definitions were combined, were voted on in round one. Two outcomes were added in round one, and as such 52 outcomes were voted on in two lists in rounds two and three. The COSs for studies of RFM awareness and clinical management are comprised of eight outcomes (four maternal and four neonatal) and 10 outcomes (two maternal and eight neonatal), respectively. Conclusions: These COSs provide researchers with the minimum set of outcomes to be measured and reported in studies relating to the awareness and the clinical management of RFM.</p

Modeling body size evolution in Felidae under alternative phylogenetic hypotheses

The use of phylogenetic comparative methods in ecological research has advanced during the last twenty years, mainly due to accurate phylogenetic reconstructions based on molecular data and computational and statistical advances. We used phylogenetic correlograms and phylogenetic eigenvector regression (PVR) to model body size evolution in 35 worldwide Felidae (Mammalia, Carnivora) species using two alternative phylogenies and published body size data. The purpose was not to contrast the phylogenetic hypotheses but to evaluate how analyses of body size evolution patterns can be affected by the phylogeny used for comparative analyses (CA). Both phylogenies produced a strong phylogenetic pattern, with closely related species having similar body sizes and the similarity decreasing with increasing distances in time. The PVR explained 65% to 67% of body size variation and all Moran's I values for the PVR residuals were non-significant, indicating that both these models explained phylogenetic structures in trait variation. Even though our results did not suggest that any phylogeny can be used for CA with the same power, or that “good” phylogenies are unnecessary for the correct interpretation of the evolutionary dynamics of ecological, biogeographical, physiological or behavioral patterns, it does suggest that developments in CA can, and indeed should, proceed without waiting for perfect and fully resolved phylogenies

Low-energy cutoffs in electron spectra of solar flares: statistical survey

The Ramaty High Energy Solar Spectroscopic Imager (RHESSI) X-ray data base (February 2002 -- May 2006) has been searched to find solar flares with weak thermal components and flat photon spectra. Using a regularised inversion technique, we determine the mean electron flux distribution from count spectra of a selection of events with flat photon spectra in the 15--20 keV energy range. Such spectral behaviour is expected for photon spectra either affected by photospheric albedo or produced by electron spectra with an absence of electrons in a given energy range, e.g. a low-energy cutoff in the mean electron spectra of non-themal particles. We have found 18 cases which exhibit a statistically significant local minimum (a dip) in the range of 10--20 keV. The positions and spectral indices of events with low-energy cutoff indicate that such features are likely to be the result of photospheric albedo. It is shown that if the isotropic albedo correction was applied, all low-energy cutoffs in the mean electron spectrum were removed and hence the low energy cutoffs in the mean electron spectrum of solar flares above $\sim$12 keV cannot be viewed as real features in the electron spectrum. If low-energy cutoffs exist in the mean electron spectra, the energy of low energy cutoffs should be less than $\sim$12 keV.Comment: 9 pages, 5 figures, submitted to Solar Physic