The food seeking behavior of slime mold: a macroscopic approach

Starting from a particle model we derive a macroscopic aggregation-diffusion equation for the evolution of slime mold under the assumption of propagation of chaos in the large particle limit. We analyze properties of the macroscopic model in the stationary case and study the behavior of the slime mold between food sources. The efficient numerical simulation of the aggregation-diffusion equation allows for a detailed analysis of the interplay between the different regimes drift, interaction and diffusion.Comment: 23 pages, 11 figure

Fast computational aeroelastic analysis of helicopter rotor blades

The use of a new aeroelastic computer framework called Flexit is described and the frame-work is used to analyse the dynamic aeroelastic behaviour of a four-bladed helicopter main rotor. Flexit implements a loose coupling between unsteady vortex lattice method (UVLM) and numerical solution of the inhomogeneous Euler-Bernoulli partial differential equation (PDE).The framework is fast because most of the intensive computational functionality is performed on GPU using NVIDIA CUDA technology, and this makes it suitable for use in the early de-sign stages. The UVLM algorithm uses a free wake model, and solution of the Euler-Bernoulli PDE is approximated using a finite difference algorithm that includes a term to take account of centrifugal forces. The results of simulations are compared with analysis performed with CFD and FSI tools

Fibre optic sensing for measuring rotor blade structural dynamics.

Researchers and practitioners spend much e ort in developing theoretical methods to design and predict the performance of helicopter rotor blades. These blades have evolved to become complex structures designed to operate in extreme conditions and over the exceptionally broad flight envelopes of helicopters. As a result, these vehicles are subject to strict maintenance regimes that increase the overall operational costs. The need to reduce such costs and improve aircraft performance together with the emergence of novel fibre optic-based sensor technologies form the context of the research presented in this thesis. Opportunities for blade health and usage monitoring created by sensor technologies such as fibre Bragg gratings (FBG) for measuring strain and direct fibre optic shape sensing (DFOSS) present today's industry with a critical question: Does the designer follow contemporary technological trends and adopt a preventative approach where he/she invests in such instrumentation systems or is a reactive approach more appropriate where he/she awaits to have sufficient evidence of operational need? A survey was carried out as part of this research to understand this dichotomy faced by rotorcraft engineers and systems architects. Adhering to the safety orientated culture within the aerospace community, the aim of this research work is the numerical and experimental exploration of challenges associated with the deployment of fibre optic instrumentation systems for future health and usage monitoring. This was achieved through three objectives: (1) development of a computational framework allowing the simulation of rotor blade dynamics at an appropriate fidelity, (2) exploration of blade health monitoring capabilities using fibre optic instrumentation systems and, (3) laboratory-based structural testing. Health and usage monitoring capabilities were explored theoretically through a parametric damage study using the computational framework. The experimental testing highlighted the need for a sensor placement methodology for distributing FBG-based strain sensors over the blade (both in terms of spanwise and chordwise locations) for accurately recovering mode shapes. This was followed by investigating the accuracy of the novel DFOSS system by deploying it on a bearingless main rotor blade along with other commercially available instrumentation systems. Test results were used to (1) perform multi-step indirect finite element modelling to increase the accuracy of the developed structural model and, (2) to explore the suitability of FBG and DFOSS measurements for damage detection. The main finding of this work is that future rotor health and usage monitoring systems based on fibre optic sensing technologies require the development of a hybrid FBG and DFOSS instrumentation system. Although numerous areas of further work have been identified, it is hoped that the adoption of such an instrumentation system will not only help reduce operational costs but also provide much needed operational data on helicopter blade dynamics to validate methods and improve designs.PhD in Aerospac

Das Berner Beratungsmodell in der Integrationsberatung

Aufgrund des vielseitigen Klientels der Integrationsberatung sind die Beratenden mit unterschiedlichsten Problematiken konfrontiert. Die grosse Herausforderung besteht darin, möglichst individuell auf die Klienten einzugehen, in der Beratung aber trotzdem einen hohen Qualitätsstandard gewährleisten zu können. Das Berner Beratungsmodell wurde speziell aus diesem Grund entwickelt und erfüllt daher diese beiden Kriterien. Durch die Anwendung dieses Modells kann individuell auf die zu Beratenden eingegangen werden, trotzdem wird durch die Befolgung des Leitfadens die Qualität der Beratung sicher gestellt. Das Berner Beratungsmodell vom BIZ Bern-Mittelland wurde jedoch für die öffentliche Berufsberatung entwickelt und lässt sich somit nur beschränkt auf die Integrationsberatung anwenden. Die öffentliche Berufsberatung unterscheidet sich insbesondere beim Beratungsfokus und in der Beratungsdauer wesentlich von der Integrationsberatung

Ab-initio two-dimensional digital twin for quantum computer benchmarking

Large-scale numerical simulations of the Hamiltonian dynamics of a Noisy Intermediate Scale Quantum (NISQ) computer - a digital twin - could play a major role in developing efficient and scalable strategies for tuning quantum algorithms for specific hardware. Via a two-dimensional tensor network digital twin of a Rydberg atom quantum computer, we demonstrate the feasibility of such a program. In particular, we quantify the effects of gate crosstalks induced by the van der Waals interaction between Rydberg atoms: according to an 8x8 digital twin simulation based on the current state-of-the-art experimental setups, the initial state of a five-qubit repetition code can be prepared with a high fidelity, a first indicator for a compatibility with fault-tolerant quantum computing. The preparation of a 64-qubit Greenberger-Horne-Zeilinger (GHZ) state with about 700 gates yields a 99.9% fidelity in a closed system while achieving a speedup of 35% via parallelization.Comment: 15 pages, 6 figures, 2 table

Searching for novel carbonic anhydrase inhibitors: from virtual screening to the lab bench

Carbonic Anhydrases (CAs) are zinc metalloenzymes that catalyze the reversible hydration of carbon dioxide to bicarbonate both in prokaryotes and eukaryotes. In this context, Computer Aided Drug Design strategies have emerged as powerful tools in the modern drug discovery paradigm. In particular, using ligand- and pharmacophore-based virtual screening approaches, we identified novel chemical entities with original chemotypes, that showed an interesting and selective inhibitory activity in nanomolar/low micromolar range toward CA I and CAII, isoforms. Herein, we present the hit-to-lead optimization process for these prototypes

Block training periodization in alpine skiing: effects of 11-day HIT on V O2max and performance

Attempting to achieve the high diversity of training goals in modern competitive alpine skiing simultaneously can be difficult and may lead to compromised overall adaptation. Therefore, we investigated the effect of block training periodization on maximal oxygen consumption (VO2max) and parameters of exercise performance in elite junior alpine skiers. Six female and 15 male athletes were assigned to high-intensity interval (IT, N=13) or control training groups (CT, N=8). IT performed 15 high-intensity aerobic interval (HIT) sessions in 11days. Sessions were 4×4min at 90-95% of maximal heart rate separated by 3-min recovery periods. CT continued their conventionally mixed training, containing endurance and strength sessions. Before and 7days after training, subjects performed a ramp incremental test followed by a high-intensity time-to-exhaustion (tlim) test both on a cycle ergometer, a 90-s high-box jump test as well as countermovement (CMJ) and squat jumps (SJ) on a force plate. IT significantly improved relative VO2max by 6.0% (P<0.01; male +7.5%, female +2.1%), relative peak power output by 5.5% (P<0.01) and power output at ventilatory threshold 2 by 9.6% (P<0.01). No changes occurred for these measures in CT. tlim remained unchanged in both groups. High-box jump performance was significantly improved in males of IT only (4.9%, P<0.05). Jump peak power (CMJ −4.8%, SJ −4.1%; P<0.01), but not height decreased in IT only. For competitive alpine skiers, block periodization of HIT offers a promising way to efficiently improve VO2max and performance. Compromised explosive jump performance might be associated with persisting muscle fatigu

Colonização Germânica no Vale do Taquari: os colonos católicos de Santa Clara (século XIX)

O presente trabalho consiste na pesquisa e análise sobre o histórico de colonização germânica no Vale do Taquari, enfocando-se a Fazenda Santa Clara, localizada atualmente no município de Santa Clara do Sul/RS, no século XIX. Buscou-se analisar diversas fontes históricas, encontradas em diferentes acervos no estado do Rio Grande do Sul, bem como analisar diversas bibliografias que tratam sobre a imigração e colonização. A partir destes estudos, foi possível observar o processo de colonização no Vale do Taquari, bem como a organização e constituição da Fazenda Santa Clara e de outras comunidades próximas, em suas primeiras décadas de ocupação. Investigou-se a forte presença de germânicos católicos nesta comunidade, buscando compreender as suas características religiosas e as relações inter-étnicas com as outras comunidades localizadas na proximidade. Objetivou-se, assim, contribuir para uma melhor compreensão destes processos históricos do Vale do Taquari e de Santa Clara do Sul

Synthese, Katalyse und Mechanismen reaktiver Edelmetall-Komplexe eines sterisch abgeschirmten N-heterocyclischen Carbens

Seit der Isolierung des ersten stabilen freien N-heterocyclischen Carbens von Arduengo et al. im Jahre 1991 hat diese Substanzklasse eine breite Anwendung in der Katalyse und als Liganden von Metallkomplexen gefunden. Dabei zeichnen sie sich vor allem durch ihre, im Vergleich zu Phosphanen, erhöhte σ-Donorfähigkeit aus und können so oftmals zu einer besseren Stabilisierung von Intermediaten führen. Neben ihren elektronischen Eigenschaften besitzen N-heterocyclische Carbene häufig einen größeren sterischen Anspruch als Phosphanliganden, was ebenfalls einen Einfluss auf die Stabilität von Metallkomplexen haben kann. In dieser Arbeit wurde das sterisch anspruchsvolle N-heterocyclische Carben IPr** untersucht. Ausgehend vom Imidazoliumsalz bzw. Silberkomplex von IPr** konnten zahlreiche Komplexe mit folgenden Übergangsmetallen erhalten werden: Platin, Kupfer, Palladium und Gold. Die Goldkomplexe IPr**AuCl (11) und IPr**AuNTf2 (12) wurden eingehender untersucht. So führte die Chloridabstraktion von IPr**AuCl (11) mit einem Silbersalz zur Bildung eines kationischen Toluol-stabilisierten Goldkomplexes. Bei der Reaktion in Dichlormethan gelang die Isolierung eines Intermediates dieser Reaktion, bei dem man die Abstraktion des Chlorids vom Goldatom durch das Silberkation beobachten kann. Wird anstelle von AgSbF6 das Natriumsalz des schwach koordinierenden BArF24-Anions als Chloridabstraktionsmittel verwendet, so konnte der entsprechende, bisher einzige nicht durch koordiniertes Lösungsmittel stabilisierte kationische 12-Valenzelektronen-Goldkomplex erhalten werden. Mit der Zeit kam es zur C-B-Bindungsspaltung des BArF24-Anions durch den kationischen Goldkomplex und zur Bildung eines Goldaryl-Komplexes. Somit ist es erstmals gelungen mit Hilfe eines Metallkomplexes der Oxidationsstufe (I) die C-B-Bindung im BArF24-Anion zu aktivieren. Ein weiteres Ziel war die Isolierung eines Gold-Carben-Komplexes durch Umsetzung des in situ darstellbaren, kationischen Goldkomplexes mit Carbenvorläufern. In dieser Arbeit konnte gezeigt werden, dass eine Gold-Kohlenstoff-Doppelbindung auf diese Art nicht erhalten werden kann. Neben der Eignung des IPr**Au-Systems, Intermediate zu stabilisieren, sind auch dessen katalytische Fähigkeiten von Interesse. Hierbei konnte IPr**AuNTf2 (12) eine bisher unerreichte Kombination von katalytischer Aktivität, Stabilität und Selektivität als Katalysator in der Hashmi-Phenolsynthese sowie der goldkatalysierten Hydratisierung von Alkinen erzielen. Die Entstehung eines isomeren Nebenproduktes in der Hashmi Phenolsynthese wurde mit Hilfe eines methylsubstituierten Furanderivats untersucht. Vermutlich beruht dessen Bildung auf einer Wagner-Meerwein-artigen-Methylgruppenverschiebung. Substituenteneffekte, relative Reaktionsgeschwindigkeiten und Konkurrenzexperimente in der goldkatalysierten Hydratisierung von Alkinen belegten, dass die Protonierung des Vinylintermediates der geschwindigkeitsbestimmende Schritt dieser Reaktion ist. Der erhaltene Palladium-PEPPSI-Komplex von IPr** wurde auf seine katalytische Aktivität in der Suzuki-Miyaura-Kreuzkupplung, der Sonogashira-Reaktion und der Buchwald-Hartwig-Aminierung getestet. Die besten Ergebnisse konnten in der Buchwald-Hartwig-Aminierung erzielt werden, welche auch in Bezug auf Katalysatorbeladung und Substratvielfalt eingehend untersucht wurde