85 research outputs found
VELOCITY AND ACCURACY AS PERFORMANCE CRITERIA FOR THREE DIFFERENT SOCCER KICKING TECHNIQUES
Kicking velocity (KV) and kicking accuracy (KA) of 19 experienced male soccer players were examined for the full instep, the inner instep, and the side foot kick. Measurements were performed simultaneously by a radar gun (KV) and a newly introduced high-speed-video camera set-up (KA). Subjects had two different tasks: to kick as fast as possible (Max KV) and to kick as accurate as possible (Max KA) with each kicking technique. Six repetitive kicks were performed for each required condition. The full instep and the inner instep kick were faster compared to the side foot kick for both performance tasks. In contrast, the side foot kick was the more accurate technique compared to the inner instep and the full instep kick, also for both performance tasks. Kicking variability between and within subjects was generally low for KV and generally high for KA for all kicking. It is concluded that velocity control is easier to achieve than accuracy control for soccer kicks
Coherently delocalized states in dipole interacting Rydberg ensembles: the role of internal degeneracies
We investigate the effect of degenerate atomic states on the exciton
delocalization of dipole-dipole interacting Rydberg assemblies. Using a frozen
gas and regular one-, two-, and three-dimensional lattice arrangements as
examples, we see that degeneracies can enhance the delocalization compared to
the situation when there is no degeneracy. Using the Zeeman splitting provided
by a magnetic field, we controllably lift the degeneracy to study in detail the
transition between degenerate and non-degenerate regimes
Topological edge states in a Rydberg composite
We examine topological phases and symmetry-protected electronic edge states
in the context of a Rydberg composite: a Rydberg atom interfaced with a
structured arrangement of ground-state atoms. The electronic Hamiltonian of
such a composite possesses a direct mapping to a tight-binding Hamiltonian,
which enables the realization and study of a variety of systems with
non-trivial topology by tuning the arrangement of ground-state atoms and the
excitation of the Rydberg atom. The Rydberg electron moves in a combined
potential including the long-ranged Coulomb interaction with the Rydberg core
and short-ranged interactions with each neutral atom; the effective
interactions between sites are determined by this combination. We first confirm
the existence of topologically-protected edge states in a Rydberg composite by
mapping it to the paradigmatic Su-Schrieffer-Heeger dimer model. Following
that, we study more complicated systems with trimer unit cells which can be
easily simulated with a Rydberg composite.Comment: 5 pages, 4 figure
Rhodium-Complex-Functionalized and Polydopamine-Coated CdSe@CdS Nanorods for Photocatalytic NAD+ Reduction
[Image: see text] We report on a photocatalytic system consisting of CdSe@CdS nanorods coated with a polydopamine (PDA) shell functionalized with molecular rhodium catalysts. The PDA shell was implemented to enhance the photostability of the photosensitizer, to act as a charge-transfer mediator between the nanorods and the catalyst, and to offer multiple options for stable covalent functionalization. This allows for spatial proximity and efficient shuttling of charges between the sensitizer and the reaction center. The activity of the photocatalytic system was demonstrated by light-driven reduction of nicotinamide adenine dinucleotide (NAD(+)) to its reduced form NADH. This work shows that PDA-coated nanostructures present an attractive platform for covalent attachment of reduction and oxidation reaction centers for photocatalytic applications
Cell cycle-independent phospho-regulation of Fkh2 during hyphal growth regulates Candida albicans pathogenesis.
The opportunistic human fungal pathogen, Candida albicans, undergoes morphological and transcriptional adaptation in the switch from commensalism to pathogenicity. Although previous gene-knockout studies have identified many factors involved in this transformation, it remains unclear how these factors are regulated to coordinate the switch. Investigating morphogenetic control by post-translational phosphorylation has generated important regulatory insights into this process, especially focusing on coordinated control by the cyclin-dependent kinase Cdc28. Here we have identified the Fkh2 transcription factor as a regulatory target of both Cdc28 and the cell wall biosynthesis kinase Cbk1, in a role distinct from its conserved function in cell cycle progression. In stationary phase yeast cells 2D gel electrophoresis shows that there is a diverse pool of Fkh2 phospho-isoforms. For a short window on hyphal induction, far before START in the cell cycle, the phosphorylation profile is transformed before reverting to the yeast profile. This transformation does not occur when stationary phase cells are reinoculated into fresh medium supporting yeast growth. Mass spectrometry and mutational analyses identified residues phosphorylated by Cdc28 and Cbk1. Substitution of these residues with non-phosphorylatable alanine altered the yeast phosphorylation profile and abrogated the characteristic transformation to the hyphal profile. Transcript profiling of the phosphorylation site mutant revealed that the hyphal phosphorylation profile is required for the expression of genes involved in pathogenesis, host interaction and biofilm formation. We confirmed that these changes in gene expression resulted in corresponding defects in pathogenic processes. Furthermore, we identified that Fkh2 interacts with the chromatin modifier Pob3 in a phosphorylation-dependent manner, thereby providing a possible mechanism by which the phosphorylation of Fkh2 regulates its specificity. Thus, we have discovered a novel cell cycle-independent phospho-regulatory event that subverts a key component of the cell cycle machinery to a role in the switch from commensalism to pathogenicity
Numerical Simulation of Turbulent Dispersions in Liquid-Liquid Extraction Columns
Die vorliegende Arbeit befasst sich mit der Simulation und Validierung von Tropfenzerfall und Tropfenaggregation in Flüssig-Flüssig Extraktionskolonnen. Dazu wird das am Fraunhofer Institut für Techno- und Wirtschaftsmathematik entwickelte CFD tool Finite Pointset Method mit der Normalized Quadrature Method of Moments gekoppelt um dieses als turbulente Zwei-Phasen Strömung formulierte Problem zu diskretisieren. Es werden essentielle Größen wie der statistische Tropfendurchmesser, der disperse Phasenanteil und die Energiedissipation numerische betrachtet und ausgewertet
Mean droplet size in stirred extraction columns. From 1D simulation to 3D FPM approach
In this joint work, a single compartment of a Kühni miniplant column is simulated using the Finite Pointset Method (FPM) with a newly added Normalized Quadrature Method of Moments (NQMOM) as population balance model (DPBM) to account for the complex droplet-droplet interactions. The available interactions models are based on the energy dissipation and several adjustable parameters. To optimize these parameters for the later use of the computationally intensive three dimensional FPM simulation, a previously validated one dimensional inverse modelling was used. The estimated parameters were then applied to simulate the Kühni column which was experimentally investigated by Steinmetz at different rotational speeds. A comparision of the one dimensional simulation showed a good agreement with respect to the droplet size at different boundary conditions. A use of the estimated parameters for the three dimensional FPM simulation was possible due to the same average turbulent energy dissipation in both simulation tools. A final use of the estimated parameters for the three dimensional simulations, the newly developed FPM/DPBM simulation code, could predict the integral droplet size with good accuracy
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