375 research outputs found
Within-subject Intra- and Inter-method consistency of two experimental risk attitude elicitation
We compare the consistency of choices in two methods to used elicit risk preferences on an aggregate as well as on an individual level. We asked subjects to choose twice from a list of nine decision between two lotteries, as introduced by Holt and Laury (2002, 2005) alternating with nine decisions using the budget approach introduced by Andreoni and Harbaugh (2009). We find that while on an aggregate (subject pool) level the results are (roughly) consistent, on an individual (within-subject) level, behavior is far from consistent. Within each method as well as across methods we observe low correlations. This again questions the reliability of experimental risk elicitation measures and the ability to use results from such methods to control for the risk aversion of subjects when explaining effects in other experimental games.risk preferences, laboratory experiment, elicitation methods, subject heterogeneity
Ligand-receptor binding kinetics in surface plasmon resonance cells: A Monte Carlo analysis
Surface plasmon resonance (SPR) chips are widely used to measure association
and dissociation rates for the binding kinetics between two species of
chemicals, e.g., cell receptors and ligands. It is commonly assumed that
ligands are spatially well mixed in the SPR region, and hence a mean-field rate
equation description is appropriate. This approximation however ignores the
spatial fluctuations as well as temporal correlations induced by multiple local
rebinding events, which become prominent for slow diffusion rates and high
binding affinities. We report detailed Monte Carlo simulations of ligand
binding kinetics in an SPR cell subject to laminar flow. We extract the binding
and dissociation rates by means of the techniques frequently employed in
experimental analysis that are motivated by the mean-field approximation. We
find major discrepancies in a wide parameter regime between the thus extracted
rates and the known input simulation values. These results underscore the
crucial quantitative importance of spatio-temporal correlations in binary
reaction kinetics in SPR cell geometries, and demonstrate the failure of a
mean-field analysis of SPR cells in the regime of high Damk\"ohler number Da >
0.1, where the spatio-temporal correlations due to diffusive transport and
ligand-receptor rebinding events dominate the dynamics of SPR systems.Comment: 21 pages, 9 figure
Infinite hierarchy of nonlinear Schrödinger equations and their solutions
We study the infinite integrable nonlinear Schrödinger equation (NLSE) hierarchy beyond the Lakshmanan-Porsezian-Daniel equation which is a particular (fourth-order) case of the hierarchy. In particular, we present the generalized Lax pair and generalized soliton solutions, plane wave solutions, AB breathers, Kuznetsov-Ma breathers, periodic solutions and rogue wave solutions for this infinite order hierarchy. We find that 'even' order equations in the set affect phase and 'stretching factors' in the solutions, while 'odd' order equations affect the velocities. Hence 'odd' order equation solutions can be real functions, while 'even' order equation solutions are always complex
High synovial expression of the inhibitory FcγRIIb in rheumatoid arthritis
Activating Fc gamma receptors (FcγRs) have been identified as having important roles in the inflammatory joint reaction in rheumatoid arthritis (RA) and murine models of arthritis. However, the role of the inhibitory FcγRIIb in the regulation of the synovial inflammation in RA is less known. Here we have investigated synovial tissue from RA patients using a novel monoclonal antibody (GB3) specific for the FcγRIIb isoform. FcγRIIb was abundantly expressed in synovia of RA patients, in sharp contrast to the absence or weak staining of FcγRIIb in synovial biopsies from healthy volunteers. In addition, the expression of FcγRI, FcγRII and FcγRIII was analyzed in synovia obtained from early and late stages of RA. Compared with healthy synovia, which expressed FcγRII, FcγRIII but not FcγRI, all activating FcγRs were expressed and significantly up-regulated in RA, regardless of disease duration. Macrophages were one of the major cell types in the RA synovium expressing FcγRIIb and the activating FcγRs. Anti-inflammatory treatment with glucocorticoids reduced FcγR expression in arthritic joints, particularly that of FcγRI. This study demonstrates for the first time that RA patients do not fail to up-regulate FcγRIIb upon synovial inflammation, but suggests that the balance between expression of the inhibitory FcγRIIb and activating FcγRs may be in favour of the latter throughout the disease course. Anti-inflammatory drugs that target activating FcγRs may represent valuable therapeutics in this disease
Glutaconate CoA-transferase from Acidaminococcus fermentans: the crystal structure reveals homology with other CoA-transferases
AbstractBackground: Coenzyme A-transferases are a family of enzymes with a diverse substrate specificity and subunit composition. Members of this group of enzymes are found in anaerobic fermenting bacteria, aerobic bacteria and in the mitochondria of humans and other mammals, but so far none have been crystallized. A defect in the human gene encoding succinyl-CoA: 3-oxoacid CoA-transferase causes a metabolic disease which leads to severe ketoacidosis, thus reflecting the importance of this family of enzymes. All CoA-transferases share a common mechanism in which the CoA moiety is transferred from a donor (e.g. acetyl CoA) to an acceptor, (R)-2-hydroxyglutarate, whereby acetate is formed. The transfer has been described by a ping-pong mechanism in which CoA is bound to the active-site residue of the enzyme as a covalent thiol ester intermediate. We describe here the crystal structure of glutaconate CoA-transferase (GCT) from the strictly anaerobic bacterium Acidaminococcus fermentans. This enzyme activates (R)-2-hydroxyglutarate to (R)-2-hydroxyglutaryl-CoA in the pathway of glutamate fermentation. We initiated this project to gain further insight into the function of this enzyme and the structural basis for the characteristics of CoA-transferases.Results: The crystal structure of GCT was solved by multiple isomorphous replacement to 2.55 Å resolution. The enzyme is a heterooctamer and its overall arrangement of subunits can be regarded as an (AB)4tetramer obeying 222 symmetry. Both subunits A and B belong to the open α/β-protein class and can be described as a four-layered α/α/β/α type with a novel composition and connectivity of the secondary structure elements. The core of subunit A consists of seven α/β repeats resulting in an all parallel central β sheet, against which helices pack from both sides. In contrast, the centre of subunit B is formed by a ninefold mixed β sheet. Inboth subunits the helical C terminus is folded back onto the N-terminal domain to form the third layer of helices.Conclusions: The active site of GCT is located at the interface of subunits A and B and is formed by loops of both subunits. The funnel-shaped opening to the active site has a depth and diameter of about 20 Å with the catalytic residue, Glu54 of subunit B, at the bottom. The active-site glutamate residue is stabilized by hydrogen bonds. Despite very low amino acid sequence similarity, subunits A and B reveal a similar overall fold. Large parts of their structures can be spatially superimposed, suggesting that both subunits have evolved from a common ancestor
Estimates of Toxoplasmosis Incidence Based on Healthcare Claims Data, Germany, 2011–2016
Toxoplasmosis is a zoonotic infection contracted through Toxoplasma gondii–contaminated food, soil, or water. Seroprevalence in Germany is high, but estimates of disease incidence are scarce. We investigated incidences for various toxoplasmosis manifestations using anonymized healthcare claims data from Germany for 2011–2016. Patients with a toxoplasmosis diagnosis during the annual observational period were considered incident. The estimated incidence was adjusted to the general population age/sex distribution. We estimated an annual average of 8,047 toxoplasmosis patients in Germany. The average incidence of non–pregnancy-associated toxoplasmosis patients was 9.6/100,000 population. The incidence was highest in 2011, at 10.6 (95% CI 9.4–12.6)/100,000 population, and lowest in 2016, at 8.0 (95% CI 7.0–9.4)/100,000 population. The average incidence of toxoplasmosis during pregnancy was 40.3/100,000 pregnancies. We demonstrate a substantial toxoplasmosis disease burden in Germany. Public health and food safety authorities should implement toxoplasmosis-specific prevention programs.Peer Reviewe
Analog Content-Addressable Memory from Complementary FeFETs
To address the increasing computational demands of artificial intelligence
(AI) and big data, compute-in-memory (CIM) integrates memory and processing
units into the same physical location, reducing the time and energy overhead of
the system. Despite advancements in non-volatile memory (NVM) for matrix
multiplication, other critical data-intensive operations, like parallel search,
have been overlooked. Current parallel search architectures, namely
content-addressable memory (CAM), often use binary, which restricts density and
functionality. We present an analog CAM (ACAM) cell, built on two complementary
ferroelectric field-effect transistors (FeFETs), that performs parallel search
in the analog domain with over 40 distinct match windows. We then deploy it to
calculate similarity between vectors, a building block in the following two
machine learning problems. ACAM outperforms ternary CAM (TCAM) when applied to
similarity search for few-shot learning on the Omniglot dataset, yielding
projected simulation results with improved inference accuracy by 5%, 3x denser
memory architecture, and more than 100x faster speed compared to central
processing unit (CPU) and graphics processing unit (GPU) per similarity search
on scaled CMOS nodes. We also demonstrate 1-step inference on a kernel
regression model by combining non-linear kernel computation and matrix
multiplication in ACAM, with simulation estimates indicating 1,000x faster
inference than CPU and GPU
THE POTENTIAL EFFECT OF MINI-TRAMPOLINE STIFFNESS ON TAKE-OFF BEHAVIOUR OF GYMNASTS – A METHODOLOGICAL STUDY
The purpose of this study was to compare two mini-trampolines with different spring constant in regard to their effect on take-off mechanics. It was expected that the softer (36 springs) trampoline would lead to a longer contact time and a higher take-off impulse. To assess reaction forces during jumps a flexible force insole was used simultaneously with the measurement of run-in velocity by timing gates. Results showed no significant differences in contact mechanics or contact time indicating that the difference between these two trampolines is only marginal. Therefore, this study provides mainly a novel measurement approach to assess the effect of equipment changes in trampolining. Future studies are warranted to assess the athlete-equipment interaction in greater detail
The Subarcsecond Mid-Infrared View of Local Active Galactic Nuclei. IV. The L- and M-band Imaging Atlas
We present the largest currently existing subarcsecond 3-5 m atlas of
119 local () active galactic nuclei (AGN). This atlas includes AGN of
5 subtypes: 22 are Seyfert 1; 5 are intermediate Seyferts; 46 are Seyfert 2; 26
are LINERs; and 20 are composites/starbursts. Each AGN was observed with VLT
ISAAC in the - and/or -bands between 2000 and 2013. We detect at
3 confidence 92 sources in the -band and 83 sources in the -band.
We separate the flux into unresolved nuclear flux and resolved flux through
two-Gaussian fitting. We report the nuclear flux, extended flux, apparent size,
and position angle of each source, giving upper-limits for sources
which are undetected. Using WISE W1- and W2-band photometry we derive relations
predicting the nuclear and fluxes for Sy1 and Sy2 AGN based on their
W1-W2 color and WISE fluxes. Lastly, we compare the measured mid-infrared
colors to those predicted by dusty torus models SKIRTOR, CLUMPY, CAT3D, and
CAT3D-WIND, finding best agreement with the latter. We find that models
including polar winds best reproduce the 3-5m colors, indicating that
winds are an important component of dusty torus models. We find that several
AGN are bluer than models predict. We discuss several explanations for this and
find that it is most plausibly stellar light contamination within the ISAAC
-band nuclear fluxes.Comment: Main Text: 22 pages, 9 figures, 3 tables. Accepted by Ap
Why Chromatic Imaging Matters
During the last two decades, the first generation of beam combiners at the
Very Large Telescope Interferometer has proved the importance of optical
interferometry for high-angular resolution astrophysical studies in the near-
and mid-infrared. With the advent of 4-beam combiners at the VLTI, the u-v
coverage per pointing increases significantly, providing an opportunity to use
reconstructed images as powerful scientific tools. Therefore, interferometric
imaging is already a key feature of the new generation of VLTI instruments, as
well as for other interferometric facilities like CHARA and JWST. It is thus
imperative to account for the current image reconstruction capabilities and
their expected evolutions in the coming years. Here, we present a general
overview of the current situation of optical interferometric image
reconstruction with a focus on new wavelength-dependent information,
highlighting its main advantages and limitations. As an Appendix we include
several cookbooks describing the usage and installation of several state-of-the
art image reconstruction packages. To illustrate the current capabilities of
the software available to the community, we recovered chromatic images, from
simulated MATISSE data, using the MCMC software SQUEEZE. With these images, we
aim at showing the importance of selecting good regularization functions and
their impact on the reconstruction.Comment: Accepted for publication in Experimental Astronomy as part of the
topical collection: Future of Optical-infrared Interferometry in Europ
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