474 research outputs found
Using empirical orthogonal functions derived from remote sensing reflectance for the prediction of concentrations of phytoplankton pigments.
The composition and abundance of algal pigments provide information on characteristics of a phytoplankton community in respect to its photoacclimation, overall biomass, and taxonomic composition. Particularly, these pigments play a major role in photoprotection and in the light-driven part of photosynthesis. Most phytoplankton pigments can be measured by High Performance Liquid Chromatography (HPLC) techniques to filtered water samples. This method, like others when water samples have to be analysed in the laboratory, is time consuming and therefore only a limited number of data points can be obtained. In order to receive information on phytoplankton pigment composition with a higher temporal and spatial resolution, we have developed a method to assess pigment concentrations from continuous optical measurements. The method applies an Empirical Orthogonal Function (EOF) analysis to remote sensing reflectance data derived from ship-based hyper-spectral underwater radiometric and from multispectral satellite data (using the MERIS Polymer product developed by Steinmetz et al., 2011) measured in the Eastern Tropical Atlantic. Subsequently we developed statistically linear models with measured (collocated) pigment concentrations as the response variable and EOF loadings as predictor variables. The model results, show that surface concentrations of a suite of pigments and pigment groups can be well predicted from the ship-based reflectance measurements, even when only a multi-spectral resolution is chosen (i.e. eight bands similar to those used by MERIS). Based on the MERIS reflectance data, concentrations of total and monovinyl chlorophyll a and the groups of photoprotective and photosynthetic carotenoids can be predicted with high quality. The fitted statistical model constructed on the satellite reflectance data as input was applied to one month of MERIS Polymer data to predict the concentration of those pigment groups for the whole Eastern Tropical Atlantic area. Bootstrapping explorations of cross-validation error indicate that the method can produce reliable predictions with relatively small data sets (e.g., < 50 collocated values of reflectance and pigment concentration). The method allows for the derivation of time series from continuous reflectance data of various pigment groups at various regions, which can be used to study variability and change of phytoplankton composition and photo-physiology
Phase ordering and shape deformation of two-phase membranes
Within a coupled-field Ginzburg-Landau model we study analytically phase
separation and accompanying shape deformation on a two-phase elastic membrane
in simple geometries such as cylinders, spheres and tori. Using an exact
periodic domain wall solution we solve for the shape and phase ordering field,
and estimate the degree of deformation of the membrane. The results are
pertinent to a preferential phase separation in regions of differing curvature
on a variety of vesicles.Comment: 4 pages, submitted to PR
Characterization of relativistic electron bunch duration and travelling wave structure phase velocity based on momentum spectra measurements on the ARES linac at DESY
The ARES linac at DESY aims to generate and characterize ultrashort electron
bunches (fs to sub-fs duration) with high momentum and arrival time stability
for the purpose of applications related to accelerator R&D, e.g. development of
advanced and compact diagnostics and accelerating structures, test of new
accelerator components, medical applications studies, machine learning, etc.
During its commissioning phase, the bunch duration characterization of the
electron bunches generated at ARES has been performed with an RF-phasing
technique relying on momentum spectra measurements, using only common
accelerator elements (RF accelerating structures and magnetic spectrometers).
The sensitivity of the method allowed highlighting different response times for
Mo and Cs2Te cathodes. The measured electron bunch duration in a wide range of
machine parameters shows excellent agreement overall with the simulation
predictions, thus demonstrating a very good understanding of the ARES operation
on the bunch duration aspect. The importance of a precise in-situ experimental
determination of the phase velocity of the first travelling wave accelerating
structure after the electron source, for which we propose a simple new
beam-based method precise down to sub-permille variation respective to the
speed of light in vacuum, is emphasized for this purpose. A minimum bunch
duration of 20 fs rms, resolution-limited by the space charge forces, is
reported. This is, to the best of our knowledge, around 4 times shorter than
what has been previously experimentally demonstrated based on RF-phasing
techniques with a single RF structure. The present study constitutes a strong
basis for future time characterization down to the sub-fs level at ARES, using
dedicated X-band transverse deflecting structures.Comment: 17 pages, 11 figures. To be submitted to Physical Review Accelerators
and Beam
EXPERIMENTS WITH A FAST CHOPPER SYSTEM FOR INTENSE ION BEAMS
Abstract Chopper systems are used to pulse charged particle beams. In most cases, electric deflection systems are used to generate beam pulses of defined lengths and appropriate repetition rates. At high beam intensities, the field distribution of the chopper system needs to be adapted precisely to the beam dynamics in order to avoid aberrations For the Frankfurt Neutron Source FRAN
Case report: a unique pediatric case of a primary CD8 expressing ALK-1 positive anaplastic large cell lymphoma of skeletal muscle
Primary involvement of skeletal muscle is a very rare event in ALK-1 positive anaplastic large cell lymphoma (ALCL). We describe a case of a 10-year old boy presenting with a three week history of pain and a palpable firm swelling at the dorsal aspect of the left thigh. Histological examination of the lesion revealed a tumoral and diffuse polymorphic infiltration of the muscle by large lymphoid cells. Tumor cells displayed eccentric, lobulated "horse shoe" or "kidney-shape" nuclei. The cells showed immunohistochemical positivity for CD30, ALK-1, CD2, CD3, CD7, CD8, and Perforin. Fluorescence in situ hybridization analysis revealed a characteristic rearrangement of the ALK-1 gene in 2p23 leading to the diagnosis of ALK-1 positive ALCL. Chemotherapy according to the ALCL-99-NHL-BFM protocol was initiated and resulted in a complete remission after two cycles. This case illustrates the unusual presentation of a pediatric ALCL in soft tissue with a good response to chemotherapy
Recommended from our members
Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016.
[This corrects the article DOI: 10.1186/s13054-016-1208-6.]
Kinematics of the Southern Rhodope Core Complex (North Greece)
The Southern Rhodope Core Complex is a wide metamorphic dome exhumed in the northern Aegean as a result of large-scale extension
from mid-Eocene to mid-Miocene times. Its roughly triangular shape is bordered on the SW by the Jurassic and Cretaceous metamorphic
units of the Serbo-Macedonian in the Chalkidiki peninsula and on the N by the eclogite bearing gneisses of the Sideroneron
massif. The main foliation of metamorphic rocks is flat lying up to 100 km core complex width. Most rocks display a stretching
lineation trending NEâ SW. The Kerdylion detachment zone located at the SW controlled the exhumation of the core complex from
middle Eocene to mid-Oligocene. From late Oligocene to mid-Miocene exhumation is located inside the dome and is accompanied
by the emplacement of the synkinematic plutons of Vrondou and Symvolon. Since late Miocene times, extensional basin sediments
are deposited on top of the exhumed metamorphic and plutonic rocks and controlled by steep normal faults and flat-ramp-type
structures. Evidence from Thassos Island is used to illustrate the sequence of deformation from stacking by thrusting of the
metamorphic pile to ductile extension and finally to development of extensional Plio-Pleistocene sedimentary basin. Paleomagnetic
data indicate that the core complex exhumation is controlled by a 30� dextral rotation of the Chalkidiki block. Extensional
displacements are restored using a pole of rotation deduced from the curvature of stretching lineation trends at core complex
scale. It is argued that the Rhodope Core Complex has recorded at least 120 km of extension in the North Aegean, since the
last 40 My
Global-change effects on early-stage decomposition processes in tidal wetlands – implications from a global survey using standardized litter
Tidal wetlands, such as tidal marshes and mangroves, are hotspots for carbon sequestration. The preservation of organic matter (OM) is a critical process by which tidal wetlands exert influence over the global carbon cycle and at the same time gain elevation to keep pace with sea-level rise (SLR). The present study assessed the effects of temperature and relative sea level on the decomposition rate and stabilization of OM in tidal wetlands worldwide, utilizing commercially available standardized litter. While effects on decomposition rate per se were minor, we show strong negative effects of temperature and relative sea level on stabilization, as based on the fraction of labile, rapidly hydrolyzable OM that becomes stabilized during deployment. Across study sites, OM stabilization was 29 % lower in low, more frequently flooded vs. high, less frequently flooded zones. Stabilization declined by ∼ 75 % over the studied temperature gradient from 10.9 to 28.5 ∘C. Additionally, data from the Plum Island long-term ecological research site in Massachusetts, USA, show a pronounced reduction in OM stabilization by > 70 % in response to simulated coastal eutrophication, confirming the potentially high sensitivity of OM stabilization to global change. We therefore provide evidence that rising temperature, accelerated SLR, and coastal eutrophication may decrease the future capacity of tidal wetlands to sequester carbon by affecting the initial transformations of recent OM inputs to soil OM
Multimodal preoperative evaluation system in surgical decision making for rectal cancer: a randomized controlled trial
Clostridium botulinum group III: a group with dual identity shaped by plasmids, phages and mobile elements
<p>Abstract</p> <p>Background</p> <p><it>Clostridium botulinum </it>strains can be divided into four physiological groups that are sufficiently diverged to be considered as separate species. Here we present the first complete genome of a <it>C. botulinum </it>strain from physiological group III, causing animal botulism. We also compare the sequence to three new draft genomes from the same physiological group.</p> <p>Results</p> <p>The 2.77 Mb chromosome was highly conserved between the isolates and also closely related to that of <it>C. novyi</it>. However, the sequence was very different from the human <it>C. botulinum </it>group genomes. Replication-directed translocations were rare and conservation of synteny was high. The largest difference between <it>C. botulinum </it>group III isolates occurred within their surprisingly large plasmidomes and in the pattern of mobile elements insertions. Five plasmids, constituting 13.5% of the total genetic material, were present in the completed genome. Interestingly, the set of plasmids differed compared to other isolates. The largest plasmid, the botulinum-neurotoxin carrying prophage, was conserved at a level similar to that of the chromosome while the medium-sized plasmids seemed to be undergoing faster genetic drift. These plasmids also contained more mobile elements than other replicons. Several toxins and resistance genes were identified, many of which were located on the plasmids.</p> <p>Conclusions</p> <p>The completion of the genome of <it>C. botulinum </it>group III has revealed it to be a genome with dual identity. It belongs to the pathogenic species <it>C. botulinum</it>, but as a genotypic species it should also include <it>C. novyi </it>and <it>C. haemolyticum</it>. The genotypic species share a conserved chromosomal core that can be transformed into various pathogenic variants by modulation of the highly plastic plasmidome.</p
- …