What was a mortarium used for? Organic residues and cultural change in Iron Age and Roman Britain.

The Romans brought the mortarium to Britain in the first century AD, and there has long been speculation on its actual purpose. Using analysis of the residues trapped in the walls of these ‘kitchen blenders’ and comparing them with Iron Age and Roman cooking pots, the authors show that it wasn't the diet that changed — just the method of preparing certain products: plants were being ground in the mortarium as well as cooked in the pot. As well as plants, the mortars contained animal fats, including dairy products. The question that remains, however, is why these natural products were being mixed together in mortaria. Were they for food, pharmaceuticals or face creams?</jats:p

Effects of patient motion on absolute quantification of glucose metabolism in cardiac positron emission tomography (PET)

Die Positronen-Emissions-Tomographie (PET) stellt eine der leistungsfähigsten Methoden zur Bestimmung myokardialer Vitalität dar, deren Bestimmung für die Prognose und Therapie von Patienten mit koronarer Herzerkrankung elementar ist. Ziel der vorliegenden Arbeit war es, das Auftreten und die Einflüsse von Patientenbewegung anhand von klinischen und simulierten Daten zu untersuchen. Ein numerisches Herzmodell wurde neu entwickelt, die Einflüsse von künstlichen Bewegungen auf das Modell und klinische Daten untersucht und diese Ergebnisse mit bewegungskontaminierten klinischen Daten verglichen. Es wurde festgestellt, dass Patientenbewegung in mehr als einem Drittel der PET-Untersuchungen auftritt. Die simulierten Bewegungsartefakte zeigten gleiche Ergebnisse für das Modell und die klinischen Daten. Der Vergleich mit klinischen Bewegungsartefakten bestätigt diese Ergebnisse. Positron-Emission-Tomography (PET) is one of the most efficient methods for the assessment of myocardial vitality, the assessment of which is fundamental for prognosis and therapy of coronary artery disease. Aim of this work was to determine the occurence and influence of patient motion by means of clinical and simulated data. A numerical model of the heart was newly developed. The influences of artificial motion on the model and clinical data was investigated and compared with clinical data. It was shown that patient motion occurs in more than a third of the PET-investigations. Simulated effects of motion were similar in the model and the clinical data. These results are comparable to those of clinical motion-biased data

Quantum simulation of frustrated magnetism in triangular optical lattices

Magnetism plays a key role in modern technology as essential building block of many devices used in daily life. Rich future prospects connected to spintronics, next generation storage devices or superconductivity make it a highly dynamical field of research. Despite those ongoing efforts, the many-body dynamics of complex magnetism is far from being well understood on a fundamental level. Especially the study of geometrically frustrated configurations is challenging both theoretically and experimentally. Here we present the first realization of a large scale quantum simulator for magnetism including frustration. We use the motional degrees of freedom of atoms to comprehensively simulate a magnetic system in a triangular lattice. Via a specific modulation of the optical lattice, we can tune the couplings in different directions independently, even from ferromagnetic to antiferromagnetic. A major advantage of our approach is that standard Bose-Einstein-condensate temperatures are sufficient to observe magnetic phenomena like N\'eel order and spin frustration. We are able to study a very rich phase diagram and even to observe spontaneous symmetry breaking caused by frustration. In addition, the quantum states realized in our spin simulator are yet unobserved superfluid phases with non-trivial long-range order and staggered circulating plaquette currents, which break time reversal symmetry. These findings open the route towards highly debated phases like spin-liquids and the study of the dynamics of quantum phase transitions.Comment: 5 pages, 4 figure

A sub-basin scale dust plume source frequency inventory for southern Africa, 2005-2008

We present a dust plume source inventory for southern Africa. In order to locate and track the local, short-lived plume events, source and frequency data have been derived from Meteosat Second Generation (MSG) thermal infrared composite data (4 km data using 8.7, 10.8, and 12.0 µm) and Moderate Resolution Imaging Spectroradiometer (MODIS) visible composite data (0.25 km data utilizing 0.620 – 0.670 µm, 0.545 – 0.565 µm, and 0.459 – 0.479 µm). Between January 2005 and December 2008, a total of 328 distinct daytime dust plumes more than 10 km in length were detected. These plumes were attributed to 101 distinct point sources, consisting largely of ephemeral inland lakes, coastal pans as well as dry river valleys in Namibia, Botswana, and South Africa. These data also provided sub-basin scale source observations for large basins such as Etosha and Makgadikgadi Pans

Epitaxial growth of deposited amorphous layer by laser annealing

We demonstrate that a single short pulse of laser irradiation of appropriate energy is capable of recrystallizing in open air an amorphous Si layer deposited on a (100) single-crystal substrate into an epitaxial layer. The laser pulse annealing technique is shown to overcome the interfacial oxide obstacle which usually leads to polycrystalline formation in normal thermal annealing

Analog of photon-assisted tunneling in a Bose-Einstein condensate

We study many-body tunneling of a small Bose-Einstein condensate in a periodically modulated, tilted double-well potential. Periodic modulation of the trapping potential leads to an analog of photon-assisted tunneling, with distinct signatures of the interparticle interaction visible in the amount of particles transferred from one well to the other. In particular, under experimentally accessible conditions there exist well-developed half-integer Shapiro-like resonances.Comment: 4 pages, 4 figures, RevTe

Bose-Hubbard model on two-dimensional line graphs

We construct a basis for the many-particle ground states of the positive hopping Bose-Hubbard model on line graphs of finite 2-connected planar bipartite graphs at sufficiently low filling factors. The particles in these states are localized on non-intersecting vertex-disjoint cycles of the line graph which correspond to non-intersecting edge-disjoint cycles of the original graph. The construction works up to a critical filling factor at which the cycles are close-packed.Comment: 9 pages, 5 figures, figures and conclusions update

Superfluid-insulator transition in a periodically driven optical lattice

We demonstrate that the transition from a superfluid to a Mott insulator in the Bose-Hubbard model can be induced by an oscillating force through an effective renormalization of the tunneling matrix element. The mechanism involves adiabatic following of Floquet states, and can be tested experimentally with Bose-Einstein condensates in periodically driven optical lattices. Its extension from small to very large systems yields nontrivial information on the condensate dynamics.Comment: 4 pages, 4 figures, RevTe

Tunable gauge potential for neutral and spinless particles in driven lattices

We present a universal method to create a tunable, artificial vector gauge potential for neutral particles trapped in an optical lattice. The necessary Peierls phase of the hopping parameters between neighboring lattice sites is generated by applying a suitable periodic inertial force such that the method does not rely on any internal structure of the particles. We experimentally demonstrate the realization of such artificial potentials, which generate ground state superfluids at arbitrary non-zero quasi-momentum. We furthermore investigate possible implementations of this scheme to create tuneable magnetic fluxes, going towards model systems for strong-field physics