General ε\varepsilon-representation for scalar one-loop Feynman integrals

A systematic study of the scalar one-loop two-, three-, and four-point Feynman integrals is performed. We consider all cases of mass assignment and external invariants and derive closed expressions in arbitrary space-time dimension in terms of higher transcendental functions. The integrals play a role as building blocks in general higher-loop or multi-leg processes. We also perform numerical checks of the calculations using AMBRE/MB and LoopTools/FF.Comment: 5 pages Latex,Contribution to the Proceedings of QCD 15, Montpellier, July 201

Scalar one-loop vertex integrals as meromorphic functions of space-time dimension d

Representations are derived for the basic scalar one-loop vertex Feynman integrals as meromorphic functions of the space-time dimension $d$ in terms of (generalized) hypergeometric functions $_2F_1$ and $F_1$. Values at asymptotic or exceptional kinematic points as well as expansions around the singular points at $d=4+2n$, $n$ non-negative integers, may be derived from the representations easily. The Feynman integrals studied here may be used as building blocks for the calculation of one-loop and higher-loop scalar and tensor amplitudes. From the recursion relation presented, higher n-point functions may be obtained in a straightforward manner.Comment: 9 pages, talk presented by TR at workshop "Matter To The Deepest", XLI International Conference on Recent Developments in Physics of Fundamental Interactions (MTTD 2017), September 3-8, 2017, Podlesice, Poland, to appear in the proceeding

QED and Electroweak Corrections to Deep Inelastic Scattering

We describe the state of the art in the field of radiative corrections for deep inelastic scattering. Different methods of calculation of radiative corrections are reviewed. Some new results for QED radiative corrections for polarized deep inelastic scattering at HERA are presented. A comparison of results obtained by the codes POLRAD and HECTOR is given for the kinematic regime of the HERMES experiment. Recent results on radiative corrections to deep inelastic scattering with tagged photons are briefly discussed.Comment: 22 pages Latex, including 6 eps-figures; to appear in the Proceedings of the 3rd International Symposium on Radiative Corrections, Cracow, August 1-5, 1996, Acta Phys. Polonica

Ergebnisse der mikrobiologischen und histopathologischen Revisionsdiagnostik bei unklarem Endoprothesenversagen

Die Endoprothetik ist eine der erfolgreichsten operativen Behandlungs-methoden der modernen Medizin und bietet Patienten mit fortgeschrittener Arthrose eine etablierte Therapiemöglichkeit. In Deutschland gehört der künst-liche Gelenkersatz im Bereich des Hüft- und Kniegelenkes zu den häufigsten durchgeführten Operationen. Bei hohen Implantationszahlen und steigender Lebenserwartung kam es in den letzten Jahren auch zu einem Anstieg der Revisionseingriffe und damit ebenso zu einem erheblichen Kostenanstieg im Gesundheitswesen. Patienten mit einem unklaren Endoprothesenversagen stellen für den behandelnden Arzt eine diagnostische Herausforderung dar, da sich die Therapie je nach Versagensursache stark unterscheiden kann. Ein Versagen der Therapie hat für den Patienten weitreichende Folgen und endet oft in multiplen Folgeoperationen und einer langer Leidenszeit. In der durchgeführten retrospektiven, monozentrischen Studie am Auguste-Viktoria-Klinikum Berlin (AVK) wurden 205 Patienten eingeschlossen, die sich im Zeitraum zwischen 2010 und 2014 mit unklarem Endoprothesenversagen vorstellten. Zur Abklärung der Versagensursache wurden laborchemische, histopathologische und mikrobiologische Befunde erhoben und ausgewertet. Zielsetzung der Arbeit war es, die erhobenen Daten statistisch auszuwerten und mit aktuellen Literaturveröffentlichungen zu vergleichen. Es sollte so der Ablauf der Revisionsdiagnostik am AVK evaluiert und gegebenenfalls angepasst bzw. verbessert werden. Darüber hinaus sollten anhand der vergleichsweise großen Datenmenge auch wesentliche Schlüsse auf die Problematik der Diagnostik gezogen werden und in grundlegende Empfehlungen münden. Die 205 eingeschlossenen Patienten waren im Durchschnitt 68,9 Jahre alt. An ihnen wurden 308 Untersuchungen hauptsächlich im Bereich der Knie- (53,7 %) und Hüft- (43,3 %), weniger im Bereich der Schultergelenke (2,9 %) durchge-führt. Periprothetische Membranen vom Typ I (25,7 %) und Typ II (22,4 %) konnten in der histopathologischen Probenuntersuchung am häufigsten nach-gewiesen werden. Die Mikrobiologie lieferte in nur 19,5 % der Untersuchungen einen Erregernachweis, den Großteil machten dabei die Koagulase-negativen Staphylokokken aus (46,0 %). Deutlich seltener wurden Streptokokken (13,0 %) oder Staph. aureus (12,0 %) nachgewiesen. Insgesamt lag in unserem Patientengut bei 29,2 % der Untersuchungen eine periprothetische Infektion (PPI) vor. Die höchste Sensitivität (88,9 %) und Spezifität (99,5 %) bei der Detektion von PPIs erreichte dabei die histopathologische Probenuntersuchung. Die Entnahme der Proben über einen perkutanen Zugang lieferte gleiche Ergebnisse wie bei offener Entnahme und sollte zur Revisionsdiagnostik vor offener Operation stets in Betracht gezogen werden. Die Mikrobiologie erreichte vor allem bei der Sensitivität (54,4 %) schlechtere Werte (Spezifität 95,0 %). Insgesamt entsprachen die Ergebnisse der histopathologischen und mikro-biologischen Probenuntersuchung den in der Literatur veröffentlichten. Es konnte ein statistisch signifikanter Zusammenhang zwischen dem Auftreten einer PPI und den Ergebnissen der Mikrobiologie und Histopathologie nach-gewiesen werden (p < 0,001). Auffallend war jedoch die relativ hohe Rate an falsch-negativen Ergebnissen in der Mikrobiologie (45,6 %). Unter Anwendung einer ROC-Kurve konnte die AUC für den CRP-Wert (0,79) und den Blut-Leukozytenwert (0,57) zur Detektion einer PPI bestimmt werden. Es wurde bestätigt, dass der Leukozytenwert zur Detektion einer PPI ungeeignet ist. Der optimale Grenzwert für den CRP-Wert wurde mit 13 mg/l errechnet (Sensitivität 64,0 %; Spezifität 83,0 %) und bestätigt somit andere Studien, die den CRP-Grenzwert zur PPI-Detektion eher höher als 5 oder 10 mg/l ansetzen. Die hohe Wertigkeit der histopathologischen Probenuntersuchung bei der Ab-klärung von unklaren Endoprothesenversagen konnte in unserer Studie be-stätigt werden. Die Ergebnisse der mikrobiologischen Probenuntersuchung waren schlechter als in anderen Veröffentlichungen, jedoch fehlten in unserem diagnostischen Algorithmus bisher die standardmäßige Durchführung einer Gelenkpunktion unter Nutzung spezieller Abnahmekits (enthalten beispiels-weise pädiatrische Blutkulturfläschchen) sowie die Sonikation. Der dia-gnostische Algorithmus wurde daher bereits erweitert, um in zukünftigen Studien eine höhere Rate an Erregernachweisen zu ermöglichen. Die Abklärung des unklaren Endoprothesenversagens bleibt eine diagnostische Herausforderung und bedarf eines standardisierten und möglichst inter-disziplinären Vorgehens

Non-planar Feynman integrals, Mellin-Barnes representations, multiple sums

The construction of Mellin-Barnes (MB) representations for non-planar Feynman diagrams and the summation of multiple series derived from general MB representations are discussed. A basic version of a new package AMBREv.3.0 is supplemented. The ultimate goal of this project is the automatic evaluation of MB representations for multiloop scalar and tensor Feynman integrals through infinite sums, preferably with analytic solutions. We shortly describe a strategy of further algebraic summation.Comment: Contribution to the proceedings of the Loops and Legs 2014 conferenc

Soil to Sail - Asteroid Landers on Near-Term Sailcraft as an Evolution of the GOSSAMER Small Spacecraft Solar Sail Concept for In-Situ Characterization

Any effort which intends to physically interact with specific asteroids requires understanding at least of the composition and multi-scale structure of the surface layers, sometimes also of the interior. Therefore, it is necessary first to characterize each target object sufficiently by a precursor mission to design the mission which then interacts with the object. In small solar system body (SSSB) science missions, this trend towards landing and sample-return missions is most apparent. It also has led to much interest in MASCOT-like landing modules and instrument carriers. They integrate at the instrument level to their mothership and by their size are compatible even with small interplanetary missions. The DLR-ESTEC GOSSAMER Roadmap NEA Science Working Groups‘ studies identified Multiple NEA Rendezvous (MNR) as one of the space science missions only feasible with solar sail propulsion. The parallel Solar Polar Orbiter (SPO) study showed the ability to access any inclination and a wide range of heliocentric distances. It used a separable payload module conducting the SPO mission after delivery by sail to the proper orbit. The Displaced L1 (DL1), spaceweather early warning mission study, outlined a very lightweight sailcraft operating close to Earth, where all objects of interest to planetary defence must pass. These and many other studies outline the unique capability of solar sails to provide access to all SSSB, at least within the orbit of Jupiter. Since the original MNR study, significant progress has been made to explore the performance envelope of near-term solar sails for multiple NEA rendezvous. However, although it is comparatively easy for solar sails to reach and rendezvous with objects in any inclination and in the complete range of semi-major axis and eccentricity relevant to NEOs and PHOs, it remains notoriously difficult for sailcraft to interact physically with a SSSB target object as e.g. the HAYABUSA missions do. The German Aerospace Center, DLR, recently brought the GOSSAMER solar sail deployment technology to qualification status in the GOSSAMER-1 project and continues the development of closely related technologies for very large deployable membrane-based photovoltaic arrays in the GOSOLAR project, on which we report separately. We expand the philosophy of the GOSSAMER solar sail concept of efficient multiple sub-spacecraft integration to also include landers for one-way in-situ investigations and sample-return missions. These are equally useful for planetary defence scenarios, SSSB science and NEO utilization. We outline the technological concept used to complete such missions and the synergetic integration and operation of sail and lander. We similarly extend the philosophy of MASCOT and use its characteristic features as well as the concept of Constraints-Driven Engineering for a wider range of operations. For example, the MASCOT Mobility hopping mechanism has already been adapted to the specific needs of MASCOT2. Utilizing sensors as well as predictions, those actuators could in a further development be used to implement anti-bouncing control schemes, by counteracting with the lander‘s rotation. Furthermore by introducing sudden jerk into the lander by utilization of the mobility, layers of loose regolith can be swirled up for sampling

Self-Assembly and Conformation of Tetrapyridilporphyrin on the Ag(111) Surface

We present a low-temperature scanning tunneling microscopy (STM) study on the supramolecular ordering of tetrapyridyl-porphyrin (TPyP) molecules on Ag(111). Vapor deposition in a wide substrate temperature range reveals that TPyP molecules easily diffuse and self-assemble into large, highly ordered chiral domains. We identify two mirror-symmetric unit cells, each containing two differently oriented molecules. From an analysis of the respective arrangement it is concluded that lateral intermolecular interactions control the packing of the layer, while its orientation is induced by the coupling to the substrate. This finding is corroborated by molecular mechanics calculations. High-resolution STM images recorded at 15 K allow a direct identification of intramolecular features. This makes it possible to determine the molecular conformation of TPYP on Ag(111). The pyridyl groups are alternately rotated out of the porphyrin plane by an angle of 60°

Ambulatory sleep scoring using accelerometers—distinguishing between nonwear and sleep/wake states

Background. Differentiating nonwear time from sleep and wake times is essential forthe estimation of sleep duration based on actigraphy data. To efficiently analyze large-scale data sets, an automatic method of identifying these three different states is re-quired. Therefore, we developed a classification algorithm to determine nonwear, sleepand wake periods from accelerometer data. Our work aimed to (I) develop a new patternrecognition algorithm for identifying nonwear periods from actigraphy data based onthe influence of respiration rate on the power spectrum of the acceleration signal andimplement it in an automatic classification algorithm for nonwear/sleep/wake states;(II) address motion artifacts that occur during nonwear periods and are known to causemisclassification of these periods; (III) adjust the algorithm depending on the sensorposition (wrist, chest); and (IV) validate the algorithm on both healthy individuals andpatients with sleep disorders. Methods. The study involved 98 participants who wore wrist and chest accelerationsensors for one day of measurements. They spent one night in the sleep laboratoryand continued to wear the sensors outside of the laboratory for the remainder of theday. The results of the classification algorithm were compared to those of the referencesource: polysomnography for wake/sleep and manual annotations for nonwear/wearclassification. Results. The median kappa values for the two locations were 0.83 (wrist) and 0.84(chest). The level of agreement did not vary significantly by sleep health (good sleepersvs. subjects with sleep disorders) (p=0.348,p=0.118) or by sex (p=0.442,p=0.456).The intraclass correlation coefficients of nonwear total time between the referenceand the algorithm were 0.92 and 0.97 with the outliers and 0.95 and 0.98 after theoutliers were removed for the wrist and chest, respectively. There was no evidence of anassociation between the mean difference (and 95% limits of agreement) and the meanof the two methods for either sensor position (wrist p=0.110, chest p=0.164), and themean differences (algorithm minus reference) were 5.11 [95% LoA−15.4–25.7] and1.32 [95% LoA−9.59–12.24] min/day, respectively, after the outliers were removed. Discussion. We studied the influence of the respiration wave on the power spectrum ofthe acceleration signal for the differentiation of nonwear periods from sleep and wakeperiods. The algorithm combined both spectral analysis of the acceleration signal and rescoring. Based on the Bland-Altman analysis, the chest-worn accelerometer showed better results than the wrist-worn accelerometer

Effects of allochthonous dissolved organic matter input on microbial composition and nitrogen cycling genes at two contrasting estuarine sites

Heterotrophic bacteria are important drivers of nitrogen (N) cycling and the processing of dissolved organic matter (DOM). Projected increases in precipitation will potentially cause increased loads of riverine DOM to the Baltic Sea and likely affect the composition and function of bacterioplankton communities. To investigate this, the effects of riverine DOM from two different catchment areas (agricultural and forest) on natural bacterioplankton assemblages from two contrasting sites in the Baltic Sea were examined. Two microcosm experiments were carried out, where the community composition (16S rRNA gene sequencing), the composition of a suite of N-cycling genes (metagenomics) and the abundance and transcription of ammonia monooxygenase (amoA) genes involved in nitrification (quantitative PCR) were investigated. The river water treatments evoked a significant response in bacterial growth, but the effects on overall community composition and the representation of N-cycling genes were limited. Instead, treatment effects were reflected in the prevalence of specific taxonomic families, specific N-related functions and in the transcription of amoA genes. The study suggests that bacterioplankton responses to changes in the DOM pool are constrained to part of the bacterial community, whereas most taxa remain relatively unaffected.Peer reviewe

Molecular Nanoscience and Engineering on Surfaces

Molecular engineering of low-dimensional materials exploiting controlled self-assembly and positioning of individual atoms or molecules at surfaces opens up new pathways to control matter at the nanoscale. Our research thus focuses on the study of functional molecules and supramolecular architectures on metal substrates. As principal experimental tools we employ low-temperature scanning tunneling microscopy and spectroscopy. Here we review recent studies in our lab at UBC: Controlled manipulation of single CO molecules, self-assembled biomolecular nanogratings on Ag(111) and their use for electron confinement, as well as the organisation, conformation, metalation and electronic structure of adsorbed porphyrins