1,402 research outputs found
Radon-based Image Reconstruction for MPI using a continuously rotating FFL
Magnetic particle imaging is a relatively new tracer-based medical imaging
technique exploiting the non-linear magnetization response of magnetic
nanoparticles to changing magnetic fields. If the data are generated by using a
field-free line, the sampling geometry resembles the one in computerized
tomography. Indeed, for an ideal field-free line rotating only in between
measurements it was shown that the signal equation can be written as a
convolution with the Radon transform of the particle concentration. In this
work, we regard a continuously rotating field-free line and extend the forward
operator accordingly. We obtain a similar result for the relation to the Radon
data but with two additive terms resulting from the additional
time-dependencies in the forward model. We jointly reconstruct particle
concentration and corresponding Radon data by means of total variation
regularization yielding promising results for synthetic data.Comment: YRM & CSE Workshop on Modeling, Simulation & Optimization of Fluid
Dynamic Applications 202
Harpacticoida (Crustacea, Copepoda) across a longitudinal transect of the Vema Fracture Zone and along a depth gradient in the Puerto Rico trench
The aim of this study was the investigation of abundance, composition and biodiversity of benthic deep-sea Harpacticoida (Crustacea, Copepoda) in the Verna Fracture Zone (VFZ) and Puerto Rico trench. The study revealed a clear East-West gradient in total abundance of Harpacticoida with a westward decrease in abundances in the VFZ and significant differences in the community composition in the Eastern (East Verna) and Western Atlantic basin (West Verna) on family and genus level. The Puerto Rico trench and its upper slope did not only differ in abundance, but were distinct with respect to community composition on family and genus level. Thus, the upper slope might be considered as an ecotone, a transition zone where a rapid distinction of species composition occurs. In our study fiarea, 837 adult harpacticoid specimens could be assigned to 16 families and 1 subfamily. The most abundant families found were Ameiridae Boeck, 1865, Pseudotachidiidae Lang, 1936 and Ectinosomatidae Sars, 1903. Genera and species were investigated within selected families (Argestidae Por, 1986, Cletodidae T. Scott, 1905, Canthocamptidae Brady, 1880 and Zosimeidae Seifried, 2003) where 11 genera, and 73 species could be discriminated. Within the selected families, the genera Zosime Boeck, 1873 and Mesocletades Sars, 1909 were dominant. In the study area, a high number of singletons was detected, which might be endemic to the respective region. Furthermore, a low total number of species in the trench was observed which was attributed to frequent disturbances in the dynamic environment of the Puerto Rico trench (e.g. turbidites or seismic activity) and high adaptability of specialists and opportunists to these disturbances
Energy loss of a heavy quark produced in a finite-size quark-gluon plasma
We study the energy loss of an energetic heavy quark produced in a high
temperature quark-gluon plasma and travelling a finite distance before emerging
in the vacuum. While the retardation time of purely collisional energy loss is
found to be of the order of the Debye screening length, we find that the
contributions from transition radiation and the Ter-Mikayelian effect do not
compensate, leading to a reduction of the zeroth order (in an opacity
expansion) energy loss.Comment: QM2006 Proceedings; caption of fig 1 and ref [7] modified in v
Les discours sur lâhĂ©rĂ©ditĂ© et la reproduction
Ernst Haeckel fait partie dâun groupe de biologistes qui, au xixe siĂšcle, ont dĂ©veloppĂ© une conception de lâhĂ©rĂ©ditĂ© en rĂ©action Ă la thĂ©orie darwinienne de lâĂ©volution. DĂ©jĂ dans sa Generelle Morphologie (1866), Haeckel avait Ă©laborĂ© des lois de lâhĂ©rĂ©ditĂ© quâil continua Ă discuter dans sa NatĂŒrliche Schöpfungsgeschichte (1868) ainsi que dans sa Perigenesis der Plastidule (1876). Cet article analyse lâapproche de Haeckel dans le contexte des thĂ©ories de lâĂ©volution Ă©mergentes vers la fin du xixe siĂšcle. On suit ici les diffĂ©rentes pistes de lâapproche haeckelienne : des perspectives Ă©volutionnaires sâĂ©tendant de Lamarck jusquâĂ Darwin ont Ă©tĂ© mĂȘlĂ©es Ă des concepts de la reproduction et de la croissance et sâenrichirent aussi de nombreuses mĂ©taphores culturelles et littĂ©raires.Ernst Haeckel belongs to those 19th century biologists who early tried to develop a biological concept of heredity in response to Darwinâs theory of evolution. Already in his Generelle Morphologie (1866) Haeckel developed laws of inheritance, and he continued to discuss these in his NatĂŒrliche Schöpfungsgeschichte (1868) and the Perigenesis der Plastidule (1876). This paper analyzes Haeckelâs approach in the context of newly emerging biological theories on heredity in the late 19th century. It traces different discursive elements in Haeckelâs approach: views on evolution from Lamarck to Darwin were intermingled with concepts of reproduction and growth as well as with a variety of cultural and literary metaphors
Multithread interval scheduling with flexible machine availabilities: complexity and efficient algorithms
In the known Interval Scheduling problem with Machine Availabilities (ISMA), each machine has a contiguous availability interval, and each job has a specific time interval which has to be scheduled. The objective is to schedule all jobs such that the machinesâ availability intervals are respected or to decide that there exists no such schedule. We extend ISMA by introducing machine capacities and flexible machine end times. Using machine capacities we model parallel processing of multiple jobs per machine, which leads to the Multithread Interval Scheduling with Machine Availabilities (MISMA). Limited machine availabilities are usually due to maintenance. Time slots for maintenance at the end of a processing period are often predetermined by staff schedules before the slots are assigned to specific machines. This motivates a variant of MISMA in which the end times of the machinesâ availability intervals can be permuted, the Flexible Multithread ISMA (FLEXMISMA).
In this paper, we determine a tight classification of conditions that are required for obtaining a polynomial-time algorithm for both MISMA and FLEXMISMA. More specifically, we show that FLEXMISMA is at least as hard as MISMA. For FLEXMISMA, we present polynomial-time algorithms for instances (i) with at most two available machines at a time, and (ii) with constantly many parallel jobs at each point in time, which both also solve MISMA; (iii) with arbitrarily many machines of capacity one each, in which case MISMA is known to be NP-hard; and (iv) with jobs having length one or two, for which the complexity of MISMA remains open Furthermore, we complement result (i) by showing that both problems are NP-hard already for instances with three machines as a special case of the Vertex-Disjoint Paths problem. In contrast to (iii), we prove that increasing the capacity of machines from one to two renders FLEXMISMA NP-hard as well for arbitrarily many machines
Take an Adventure Bite
The Adventure Bites - Cooking with Kids program enhanced nutrition curriculum by including a Life Skill development focus and a family night - to improve youth nutrition behaviors. The data was collected using the WSU 4-H Life Skills pre-post youth evaluations, staff surveys, a parent retrospective pre-post survey, and comparison data from non-program sites. The results support adding Life Skills and family night events into youth nutrition curricula. There are opportunities to improve evaluation and do further testing, to determine what the individual impact of Life Skill development and/or individual impact of having family nights had on changes in youth behaviors regarding nutrition
Energy Loss of a Heavy Quark Produced in a Finite Size Medium
We study the medium-induced energy loss suffered by a
heavy quark produced at initial time in a quark-gluon plasma, and escaping the
plasma after travelling the distance . The heavy quark is treated
classically, and within the same framework consistently
includes: the loss from standard collisional processes, initial bremsstrahlung
due to the sudden acceleration of the quark, and transition radiation. The
radiative loss {\it induced by rescatterings} is not
included in our study. For a ultrarelativistic heavy quark with momentum p
\gsim 10 {\rm GeV}, and for a finite plasma with L_p \lsim 5 {\rm fm}, the
loss is strongly suppressed compared to the stationary
collisional contribution . Our results
support that is the dominant contribution to the heavy quark
energy loss (at least for L_p \lsim 5 {\rm fm}), as indeed assumed in most of
jet-quenching analyses. However they might raise some question concerning the
RHIC data on large electron spectra.Comment: 18 pages, 3 figures. New version clarified and simplified. A critical
discussion added in section 2, and previous sections 3 and 4 have been merged
together. Main results are unchange
D,L-Lysine-Acetylsalicylate + Glycine (LASAG) Reduces SARS-CoV-2 Replication and Shows an Additive Effect with Remdesivir
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causing the coronavirus disease-19 (COVID-19) is still challenging healthcare systems and societies worldwide. While vaccines are available, therapeutic strategies are developing and need to be adapted to each patient. Many clinical approaches focus on the repurposing of approved therapeutics against other diseases. However, the efficacy of these compounds on viral infection or even harmful secondary effects in the context of SARS-CoV-2 infection are sparsely investigated. Similarly, adverse effects of commonly used therapeutics against lifestyle diseases have not been studied in detail. Using mono cell culture systems and a more complex chip model, we investigated the effects of the acetylsalicylic acid (ASA) salt D,L-lysine-acetylsalicylate + glycine (LASAG) on SARS-CoV-2 infection in vitro. ASA is commonly known as Aspirin Âź and is one of the most frequently used medications worldwide. Our data indicate an inhibitory effect of LASAG on SARS-CoV-2 replication and SARS-CoV-2-induced expression of pro-inflammatory cytokines and coagulation factors. Remarkably, our data point to an additive effect of the combination of LASAG and the antiviral acting drug remdesivir on SARS-CoV-2 replication in vitro
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