Integrated Diamond Optics for Single Photon Detection

Optical detection of single defect centers in the solid state is a key element of novel quantum technologies. This includes the generation of single photons and quantum information processing. Unfortunately the brightness of such atomic emitters is limited. Therefore we experimentally demonstrate a novel and simple approach that uses off-the-shelf optical elements. The key component is a solid immersion lens made of diamond, the host material for single color centers. We improve the excitation and detection of single emitters by one order of magnitude, as predicted by theory.Comment: 10 pages, 3 figure

Global Response to Local Ionospheric Mass Ejection

We revisit a reported "Ionospheric Mass Ejection" using prior event observations to guide a global simulation of local ionospheric outflows, global magnetospheric circulation, and plasma sheet pressurization, and comparing our results with the observed global response. Our simulation framework is based on test particle motions in the Lyon-Fedder-Mobarry (LFM) global circulation model electromagnetic fields. The inner magnetosphere is simulated with the Comprehensive Ring Current Model (CRCM) of Fok and Wolf, driven by the transpolar potential developed by the LFM magnetosphere, and includes an embedded plasmaspheric simulation. Global circulation is stimulated using the observed solar wind conditions for the period 24-25 Sept 1998. This period begins with the arrival of a Coronal Mass Ejection, initially with northward, but later with southward interplanetary magnetic field. Test particles are launched from the ionosphere with fluxes specified by local empirical relationships of outflow to electrodynamic and particle precipitation imposed by the MIlD simulation. Particles are tracked until they are lost from the system downstream or into the atmosphere, using the full equations of motion. Results are compared with the observed ring current and a simulation of polar and auroral wind outflows driven globally by solar wind dynamic pressure. We find good quantitative agreement with the observed ring current, and reasonable qualitative agreement with earlier simulation results, suggesting that the solar wind driven global simulation generates realistic energy dissipation in the ionosphere and that the Strangeway relations provide a realistic local outflow description

Sensing remote nuclear spins

Sensing single nuclear spins is a central challenge in magnetic resonance based imaging techniques. Although different methods and especially diamond defect based sensing and imaging techniques in principle have shown sufficient sensitivity, signals from single nuclear spins are usually too weak to be distinguished from background noise. Here, we present the detection and identification of remote single C-13 nuclear spins embedded in nuclear spin baths surrounding a single electron spins of a nitrogen-vacancy centre in diamond. With dynamical decoupling control of the centre electron spin, the weak magnetic field ~10 nT from a single nuclear spin located ~3 nm from the centre with hyperfine coupling as weak as ~500 Hz is amplified and detected. The quantum nature of the coupling is confirmed and precise position and the vector components of the nuclear field are determined. Given the distance over which nuclear magnetic fields can be detected the technique marks a firm step towards imaging, detecting and controlling nuclear spin species external to the diamond sensor

Ermittlung der rheologischen Zustandsgleichung eines Lehmes mit Hilfe einer neuentwickelten Versuchsapparatur

Die genaue Kenntnis des mechanischen Verhaltens eines Werkstoffes ist für viele Ingenieuraufgaben Voraussetzung für die erfolgreiche Bearbeitung. In zahlreichen Fällen interessiert dabei nicht nur der Zusammenhang zwischen Spannungen und Deformationen, sondern auch die Zeitabhängigkeit der Spannungs- bzw. Deformationsänderungen. Obwohl die zuständige Wissenschaft, die Rheologie, Hilfsmittel für eine umfassende Materialbeschreibung bereitstellt, bedient sich die Bodenmechanik ihrer in nur geringem Maße. Man begnügt sich meistens mit der Annahme, daß der Boden sich - je nach Aufgabenstellung - entweder ideal elastisch oder ideal plastisch verhält. Die zeitliche Abhängigkeit kann lediglich im Falle einer Setzungsberechnung mit Hilfe der Konsolidierungstheorie ermittelt werden. Wegen der Voraussetzung der Stoffeigenschaften erhält man bei der Auswertung der üblichen Labor- und Feldversuche Modellgesetze, die streng genommen nur auf Fälle mit gleichen Randbedingungen übertragen werden dürfen. Die bisherigen Veröffentlichungen lassen erkennen, daß die verwendeten Versuchsgeräte für rheologische Versuche wenig geeignet sind. Porenwasserdruckmessungen und Erholungsphasen fehlen meist. Außerdem gibt es für das gleiche Material zu wenig Spannungs- oder Verformungsmessungen unterhalb der Bruchgrenze, so daß die mitgeteilten Versuchsdaten für die Ermittlung eines Stoffgesetzes nicht ausreichen. Aufbauend auf den Erkenntnissen der Rheologie soll hier versucht werden, für ein frei gewähltes Material die rheologische Zustandsgleichung (Stoffgesetz) unter Einhaltung klarer Randbedingungen aufzustellen. Im Sinne reiner Grundlagenforschung wurde die Neukonstruktion von geeigneten Versuchsgeräten nicht gescheut. Anregung zur vorliegenden Arbeit gab u.a. die Frage, wie die Standsicherheit einer in Bewegung geratenen Böschung beurteilt werden kann. Diese Frage wurde gestellt, als im Kaunertal, Tirol, Hangschuttmassen durch die Füllung des Gepatsch-Speichers in Bewegung gerieten (Breth (1967)[1]). In den beiden anschließenden Kapiteln folgt eine auf das vorliegende Problem zugeschnittene Kurzfassung der Rheologie sowie ein kurzer Überblick über die wichtigsten einschlägigen Experimente auf dem Gebiet der Bodenmechanik. Eine Präzisierung der Aufgabenstellung erfolgt in Kapitel 4. Eigene Versuche und deren Auswertung bilden den Schwerpunkt der Arbeit und sind in Kapitel 5 und 6 beschrieben. Im letzten Teil der Arbeit werden die gewonnenen Ergebnisse kritisch beleuchtet und noch offene Fragen für weitere Arbeiten auf diesem Gebiet behandelt

The negatively charged nitrogen-vacancy centre in diamond: the electronic solution

The negatively charged nitrogen-vacancy centre is a unique defect in diamond that possesses properties highly suited to many applications, including quantum information processing, quantum metrology, and biolabelling. Although the unique properties of the centre have been extensively documented and utilised, a detailed understanding of the physics of the centre has not yet been achieved. Indeed there persists a number of points of contention regarding the electronic structure of the centre, such as the ordering of the dark intermediate singlet states. Without a sound model of the centre's electronic structure, the understanding of the system's unique dynamical properties can not effectively progress. In this work, the molecular model of the defect centre is fully developed to provide a self consistent model of the complete electronic structure of the centre. The application of the model to describe the effects of electric, magnetic and strain interactions, as well as the variation of the centre's fine structure with temperature, provides an invaluable tool to those studying the centre and a means to design future empirical and ab initio studies of this important defect.Comment: 24 pages, 6 figures, 10 table

Testicular Damage following Testicular Sperm Retrieval: A Ram Model Study

The aim of this study was to evaluate the possible development of histological abnormalities such as fibrosis and microcalcifications after sperm retrieval in a ram model. Fourteen testicles in nine rams were exposed to open biopsy, multiple TESAs, or TESE, and the remaining four testicles were left unoperated on as controls. Three months after sperm retrieval, the testicles were removed, fixed, and cut into 1/2 cm thick slices and systematically put onto a glass plate exposing macroscopic abnormalities. Tissue from abnormal areas was cut into 3 μm sections and stained for histological evaluation. Pathological abnormalities were observed in testicles exposed to sperm retrieval (≥11 of 14) compared to 0 of 4 control testicles. Testicular damage was found independently of the kind of intervention used. Therefore, cryopreservation of excess sperm should be considered while retrieving sperm

Cutting cardiovascular risk in barbershops

http://dx.doi.org/10.1016/j.jomh.2009.07.00

Increased Use of Medications for Erectile Dysfunction in Men With Ulcerative Colitis and Crohn’s Disease Compared to Men Without Inflammatory Bowel Disease:A Nationwide Cohort Study

BACKGROUND: Men with inflammatory bowel disease (IBD) may have decreased sexual function due to factors related to the underlying disease, medication, and/or surgery. We aimed to examine the use of erectile dysfunction (ED) medications in men with IBD. Methods: This is a nationwide cohort study based on the Danish registries, comprising all men &gt;18 years old with IBD during 1 January 1995 through December 2016. The cohorts included 31,498 men with IBD and 314,980 age-matched men without IBD. Our main outcome was a first prescription of an ED medication. Cox regression analyses were used to estimate the hazard rate (HR) for use of ED medications, controlled for multiple time-varying covariates. Results: Overall, 21,966 (69.7%) men had ulcerative colitis (UC) while 9532 (30.3%) had Crohn’s disease (CD). Men with a first ED prescription numbered 3749 (11.9%) (men with IBD) and 30,635 (9.7%) (men without IBD). Adjusting for central nervous system and intestinal anti-inflammatory medications, systemic corticosteroids and co-morbidities, the HR was 1.19 (95% CI: 1.13–1.26) (IBD and no prior IBD operation), and 1.31 (95% CI: 1.20–1.43) (IBD and prior IBD operation). The adjusted HR for UC was 1.17 (95% CI: 1.10–1.24) (no operation) and 1.43 (95% CI: 1.27–1.61) (prior operation), and for CD 1.26 (95% CI: 1.15–1.38) (no operation) and 1.20 (95% CI: 1.06–1.35) (prior operation). Discussion: Men with IBD are more likely to fill an ED prescription than men without IBD. This result is significant regardless of a history of IBD surgery.</p

Products of motor burnout. Final report

The Montreal Protocol of 1987 effectively banned a long list of chlorofluorocarbons (CFCs) traditionally used in air conditioning and refrigeration applications. The refrigeration and air conditioning industries have responded by developing and testing new, alternative refrigerants that are less damaging to the atmosphere upon release. Despite a reputation for quality and reliability, air conditioning systems do occasionally fail. One of the more common failure modes in a hermetic system is a motor burnout. Motor burnouts can occur by various mechanisms. One of the most common scenarios is a locked motor rotor, which may result from a damaged bearing. The resulting electrical motor burnout is caused by overheating of the locked rotor and subsequent failure of the insulation. This is primarily a thermal breakdown process