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Intrinsic paramagnetic Meissner effect due to s-wave odd-frequency superconductivity
Full text linkIn 1933, Meissner and Ochsenfeld reported the expulsion of magnetic flux-the diamagnetic Meissner effect-from the interior of superconducting lead. This discovery was crucial in formulating the Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity. In exotic superconducting systems BCS theory does not strictly apply. A classical example is a superconductor-magnet hybrid system where magnetic ordering breaks time-reversal symmetry of the superconducting condensate and results in the stabilization of an odd-frequency superconducting state. It has been predicted that under appropriate conditions, odd-frequency superconductivity should manifest in the Meissner state as fluctuations in the sign of the magnetic susceptibility, meaning that the superconductivity can either repel (diamagnetic) or attract (paramagnetic) external magnetic flux. Here, we report local probe measurements of faint magnetic fields in a Au=Ho=Nb trilayer system using low-energy muons, where antiferromagnetic Ho (4.5 nm) breaks time-reversal symmetry of the proximity-induced pair correlations in Au. From depth-resolved measurements below the superconducting transition of Nb, we observe a local enhancement of the magnetic field in Au that exceeds the externally applied field, thus proving the existence of an intrinsic paramagnetic Meissner effect arising from an odd-frequency superconducting state.Peer reviewe
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Origin and regenerative potential of vertebrate mechanoreceptor-associated stem cells
Full text linkWidera D, Hauser S, Kaltschmidt C, Kaltschmidt B. Origin and regenerative potential of vertebrate mechanoreceptor-associated stem cells. Anatomy Research International. 2012;2012:1-9.Meissner corpuscles and Merkel cell neurite complexes are highly specialized mechanoreceptors present in the hairy and glabrous skin, as well as in different types of mucosa. Several reports suggest that after injury, such as after nerve crush, freeze injury, or dissection of the nerve, they are able to regenerate, particularly including reinnervation and repopulation of the mechanoreceptors by Schwann cells. However, little is known about mammalian cells responsible for these regenerative processes. Here we review cellular origin of this plasticity in the light of newly described adult neural crest-derived stem cell populations. We also discuss further potential multipotent stem cell populations with the ability to regenerate disrupted innervation and to functionally recover the mechanoreceptors. These capabilities are discussed as in context to cellularly reprogrammed Schwann cells and tissue resident adult mesenchymal stem cells
Meissner-Ochsenfeld superconducting anomalies in the Be-Ag-F system
No full textWe report here observations of sudden drops in the magnetic susceptibility of a large number of samples in the Be-Ag-F system, over the temperatures ranging from 8.5 to 64 K. These magnetic anomalies, strongly reminiscent of the Meissner-Ochsenfeld effect, suggest the presence of superconductivity in a small sample fraction of this fluoroargentate system, a cousin of the oxocuprate High-TC materials. © 2003 Elsevier Ltd. All rights reserved
Mettlerkamp, der Führer einer am deutschen Freiheitskriege theilnehmenden Bürgerwehr : mit Benutzung des handschriftlichen Nachlasses Mettlerkamps
No full textvon Fr. WilleMit Exlibris von Conrad Ferdinand Meyer Exemplar der Zentralbibliothek Zürich, C.F.-Meyer-BibliothekAus dem Vorbesitz von Conrad Ferdinand Meyer Exemplar der Zentralbibliothek Zürich, C.F.-Meyer-Bibliothek"Herrn K F. Meyer / in freundschaftlicher Hochachtung u Sympath / der Verfasser" Exemplar der Zentralbibliothek Zürich, C.F.-Meyer-Bibliothe
Development of a magnetic susceptibility measurement system for detecting the Meissner effect
Full text linkapplication/pdfTo identify the superconducting phase transition at low temperatures, we construct a measurement system for detecting the Meissner effect. The well-known method of the measurement system is the Hartshorn-type bridge, but we try to construct the simplified measurement system, where the cylinder of the primary coil and that of secondary ones are settle in a fixed geometrical arrangement without the Hartshorn-type bridge. In our study, we use an alternative magnetic field of HAC = H0sin(2πft) with H0 ~ 1.6 Oe and 12 < f < 4000 Hz. To test our measurement system, we measured the magnetic susceptibility of niobium and obtained very sharp and clear Meissner signal at around 8.2 K.departmental bulletin pape
The Role of Foreign Currency Debt in Financial Crises: 1880-1913 vs. 1972-1997
Full text linkWhat is the role of foreign currency debt in precipitating financial crises? In this paper we compare the 1880 to 1913 period to recent experience. We examine debt crises, currency crises, banking crises and the interrelation between these varieties of crises. We pay special attention to the role of hard currency debt, currency mismatches and debt intolerance. We find fairly robust evidence that high exposure to foreign currency debt does not necessarily lead to a high chance of having a debt crisis, currency crisis, or a banking crisis. A key finding is some countries do not suffer from great financial fragility despite high exposure to original sin. In the nineteenth century, the British offshoots and Scandinavia generally avoided severe financial meltdowns while today many advanced countries have high original sin but have had few financial crises. The common denominator in both periods is that currency mismatches matter. A strong reserve position or high exports relative to hard currency liabilities helps decrease the likelihood of a debt crisis, currency crisis or a banking crisis. This strengthens the evidence for the hypothesis that foreign currency debt is dangerous when mis-managed. We discuss the robustness of these results and make some general comparisons based on this evidence from over 60 years of intense international capital market integration.
Sistematización del diseño de dispositivos de levitación superconductora por efecto Meissner
Full text linkEsta tesis doctoral aporta un esquema sistemático para el diseño de dispositivos
de levitación magnética superconductora por efecto Meissner. Partiendo de la expresión
propuesta recientemente por Pérez-Díaz y García-Prada (PDGP) en este trabajo se
demuestra que la aplicabilidad de dicha expresión es general y se deriva de las
ecuaciones de Maxwell y London. Esta expresión, aunque deducida en el caso de
exclusión total de campo magnético o estado Meissner, permite también tratar casos de
penetración parcial de campo magnético o estado mixto superponiendo a la fuerza
Meissner la fuerza que ejerce la imanación del propio superconductor.
Además y no menos importante, se realiza una interpretación geométrica de la
expresión citada que permite demostrar que el factor de ganancia mecánica del sistema
es igual a 2 de forma local y no sólo global. Esto permite también interpretar la
estabilidad de algunos sistemas de levitación Meissner orientando así sobre su diseño.Finalmente, se calculan casos de geometrías específicas y de posible aplicación
mecánica. En concreto se calculan las fuerzas que aparecen en el caso de un imán
permanente en el interior de un cilindro de interesantes aplicaciones mecánicas.
Para realizar los cálculos se emplea el programa MAPLE v11.
Como conclusiones de este trabajo tenemos pues:
1. La expresión PDGP, así validada, es aplicable para el cálculo por
elementos finitos de cualquier geometría con la precisión que se desee.
2. Se dispone, así, de una herramienta precisa de cálculo y de un criterio de
diseño basado en la interpretación geométrica.
3. Se determina las leyes de la mecánica de un imán en el interior de un
cilindro definiendo así las disposiciones óptimas para determinados usos
mecánicos
Dipyrone is the preferred nonopioid analgesic for the treatment of acute and chronic pain. A survey of clinical practice in German-speaking countries.
No full textPURPOSE
Nonopioid analgesics are frequently used for the treatment of acute and chronic pain. Dipyrone is an alternative to NSAIDs and paracetamol, however, data on the frequency of its usage by anaesthesiologists in the perioperative and chronic pain setting are lacking and its adverse reactions are a matter of debate.
METHODS
The link to a questionnaire on the use of nonopioid analgesics (NSAIDs, COX-2 inhibitors, paracetamol, dipyrone) and the safety of dipyrone in the perioperative and chronic pain setting was mailed to anaesthesiologists and pain physicians.
RESULTS
A total of 2237 responses were analysed. About 97.4% of the respondents used nonopioid analgesics for the treatment of acute pain, with 93.8% administering dipyrone, 54.0% NSAIDs, 41.8% COX-2 inhibitors and 49.2% paracetamol. Nonopioid analgesics were administered preoperatively by 22.3%, intraoperatively by 86.1% and postoperatively by 73.0% of the respondents. For chronic pain management, 76.7% of the respondents prescribed oral dipyrone in combination with other nonopioid analgesics; 19.9% used dipyrone as sole nonopioid, whereas 2.9% denied its use. Cases of dipyrone-associated agranulocytosis were observed by 3.5% of the respondents of the acute and 1.5% of the chronic pain questionnaire, respectively. The majority of respondents (acute pain: 73.0%, chronic pain 59.3%) performed no blood cell counts to monitor dipyrone therapy. Patients were rarely informed about possible adverse drug reactions.
CONCLUSIONS
Dipyrone is the preferred nonopioid analgesic in the perioperative and chronic pain setting. Although cases of agranulocytosis occur, benefits apparently outweigh the risks according to anaesthesiologists. Measures like patient information may improve safety.
SIGNIFICANCE
A survey of anaesthesiologist in German-speaking countries revealed dipyrone as preferred nonopioid analgesic for the treatment of acute and chronic pain. Benefits seem to outweigh the risks, specifically the risk of agranulocytosis. Information of medical staff and patients on adverse drug reactions and symptoms of agranulocytosis should be implemented
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