505 research outputs found
Fixing education for the AI age: Conrad Wolfram
No full textConrad Wolfram is the CEO and co-founder of Wolfram Research Europe and Strategic Director of Wolfram Research. He is a leading advocate for mathematics education reform and author of “The Math(s) Fix: An Education Blueprint for the AI Age”. He recently gave a public lecture at LSE on this topic. The following is an edited version of an interview by Neil Olver in the Mathematics Department
Who are the Disciples and Admirers of an Author?
No full textWebcast sponsored by the Irving K. Barber Learning Centre and hosted by SLAIS. Recitation (the act of citing a given author or her/his works multiple times) provides an indication of the influence of a cited author. This study investigated patterns of citation and recitation across frequently cited authors' works to better understand how broadly citers have been influenced by cited authors and their publications. Dietmar Wolfram is Interim Dean & Professor School of Information Studies, University of Wisconsin-Milwaukee.Arts, Faculty ofLibrary, Archival and Information Studies (SLAIS), School ofUnreviewedFacult
Interest rate convexity and the volatility smile
No full textWhen pricing the convexity effect in irregular interest rate derivatives such as, e.g., Libor-in-arrears or CMS, one often ignores the volatility smile, which is quite pronounced in the interest rate options market. This note solves the problem of convexity by replicating the irregular interest flow or option with liquidly traded options with different strikes thereby taking into account the volatility smile. This idea is known among practitioners for pricing CMS caps. We approach the problem on a more general scale and apply the result to various examples. --interest rate options,volatility smile,convexity,,option replication
Comprehensive overview of disease models for Wolfram syndrome : toward effective treatments
No full textWolfram syndrome (OMIM 222300) is a rare autosomal recessive disease with a devastating array of symptoms, including diabetes mellitus, optic nerve atrophy, diabetes insipidus, hearing loss, and neurological dysfunction. The discovery of the causative gene, WFS1, has propelled research on this disease. However, a comprehensive understanding of the function of WFS1 remains unknown, making the development of effective treatment a pressing challenge. To bridge these knowledge gaps, disease models for Wolfram syndrome are indispensable, and understanding the characteristics of each model is critical. This review will provide a summary of the current knowledge regarding WFS1 function and offer a comprehensive overview of established disease models for Wolfram syndrome, covering animal models such as mice, rats, flies, and zebrafish, along with induced pluripotent stem cell (iPSC)-derived human cellular models. These models replicate key aspects of Wolfram syndrome, contributing to a deeper understanding of its pathogenesis and providing a platform for discovering potential therapeutic approaches
Two-Dimensional Bunch-Resolved Optical Beam Diagnostics at BESSY II
No full textBESSY II ist eine Strahlungsquelle der dritten Generation, die vom Helmholtz-Zentrum Berlin für Materialien und Energie GmbH für Experimente mit Synchrotronstrahlung betrieben wird. Mehrere Betriebsmodi werden am BESSY II Speicherring angeboten bzw. entwickelt, um die Anforderungen der vielfältigen Nutzergemeinde zu erfüllen. Dazu gehören nicht nur ein komplexes Füllmuster im Standardnutzerbetrieb, sondern auch spezielle Betriebsmodi mit kurzen Pulsen oder das sogenannte Transverse Resonant Island Buckets Separationsschema. Die Komplexität des Füllmusters erfordert eine pulsaufgelöste Strahldiagnose für die Inbetriebnahme und zur Sicherstellung der langfristigen Qualität des Beschleunigerbetriebs. Ferner werden für den Kurzpulsbetrieb Pulslängenmessungen mit ps Auflösung benötigt. Im Rahmen dieser Arbeit wird zu diesem Zweck eine neue Diagnoseplattform mit mehreren Strahlrohren aufgebaut. Jeweils ein Strahlrohr ist für transversale Strahlgrößenmessungen und für longitudinale Strahldiagnose vorgesehen. Beide Strahlrohre sind mit Messapperaturen für pulsaufgelöste Messungen ausgestattet. Hauptfokus dieser Arbeit liegen auf dem Design, der Installation und den Verbesserungen dieser Strahlrohre und den zugehörigen Meßgeräten in Kombination mit spezifischen Anwendungen in der Strahldiagnose an BESSY II.
Im Allgemeinen erfordern Kopplungen zwischen Zeit- und Raumkoordinaten pulsselektive und korrelierte Detektionsmethoden mehrerer Parameter. Daher sind die longitudinale Diagnose sowie die Streak Kamera so optimiert worden, dass die direkte Abbildung des transversalen Strahlprofils möglich ist und sogar interferometrische Strahlgrößenmessungen durchführbar. Zusätzlich zur Zeitachse der Streak Kamera kann entweder die horizontale oder die vertikale Dimension des Strahls abgebildet werden und dadurch sind 2D-Messungen möglich. Mit dieser Methode wurden mehrere pulsaufgelöste 2D-Messungen durchgeführt und Analysemethoden entwickelt.BESSY II is a third generation light source operated by the Helmholtz-Zentrum Berlin für Materialien und Energie GmbH for experiments with synchrotron radiation. Multiple operation modes are offered or are under development at the BESSY II storage ring to serve the needs of its diverse user community. This does not only include a complex fill pattern in standard operation, but also special operation modes featuring short pulses or the new transverse resonant island buckets separation scheme. The complexity of the fill pattern requires bunch-resolved diagnostics for commissioning and to ensure the long-term quality of accelerator operation. In addition, short pulse operation demands bunch length measurements with ps resolution. For this purpose a new diagnostics platform featuring multiple beamlines is set up. One beamline is dedicated for transverse beam size measurements and one for longitudinal diagnostics. Both beamlines are equipped with fast gated devices for bunch-resolved measurements. Design, installation and improvements of these beamlines and the measuring devices are the main focus of this work, together with specific BESSY II bunch diagnostics applications.
In general, coupling between time- and space-coordinates do call for bunch-selective and correlated multi-parameter detection methods. Thus, the longitudinal diagnostics beamline and the streak camera have been made capable of direct transverse beam-profile imaging and even interferometric beam size measurements are feasible. Either the horizontal or vertical beam dimension can be imaged in addition to the time axis of the streak camera and 2D measurements are possible. Taking advantage of these capabilities, multiple bunch-resolved 2D measurements have been performed and analysis methods have been developed
Entwicklung & Charakterisierung von Quellen für hochenergetische, hochintensive kohärente Strahlung
No full text1. Using a 2.1 µm-wavelength, few-cycle laser for high-order harmonic generation the scaling of the conversion to higher photon energies is studied. The measured photoelectron spectra extend well above 1 keV.2. Employing a loose focusing set-up, based on a high-power near-infrared laser the XUV photon flux per pulse is enhanced by orders of magnitude compared with conventional harmonic sources.3. With the scheme of attosecond streaking spectroscopy we measured the shortest available free-electron laser X-ray pulses directly in the time domain on a single-shot basis, yielding an average upper limit for the pulse duration of only a few femtoseconds and even detecting some shots with sub-femtosecond lengths. Combining the ultrahigh photon intensities with the nanoscale spatial and demonstrated attoscale temporal resolution offers an ideal tool for the investigation of light–matter interactions on their natural time scale.1. Mithilfe eines 2.1 µm-Kurzpulslasers für die Erzeugung hoher Harmonischer wird die Skalierung der Konversion zu höheren Photonenenergien untersucht. Die gemessenen Spektren reichen über 1 keV hinaus.2. Durch Verwendung eines Aufbaus mit lockerer Fokussierung und eines Hochleistungslasers im nahen infraroten Bereich wird der XUV Photonenfluss pro Puls um Größenordnungen gesteigert.3. Mit der Attosekunden-Schlierenspektroskopie wurden die derzeit kürzesten Röntgenpulse an einem Freie-Elektronen-Laser direkt in der Zeitdomäne im Einzelschuss gemessen und eine Pulslängenobergrenze von nur wenigen Femtosekunden festgestellt. Einige Schüsse waren sogar kürzer als 1 fs. Diese hochintensiven Röntgenquellen mit einer räumlich-zeitlichen Auflösung im Nanometer- bzw. Attosekundenbereich bieten ein ideales Werkzeug zur Erforschung von atomaren Wechselwirkungsprozessen auf deren natürlicher Zeitskala
Algebraic properties and the finite rank problem for Toeplitz operators on the Segal–Bargmann space
No full textAbstractWe study three different problems in the area of Toeplitz operators on the Segal–Bargmann space in Cn. Extending results obtained previously by the first author and Y.L. Lee, and by the second author, we first determine the commutant of a given Toeplitz operator with a radial symbol belonging to the class Sym>0(Cn) of symbols having certain growth at infinity. We then provide explicit examples of zero-products of non-trivial Toeplitz operators. These examples show the essential difference between Toeplitz operators on the Segal–Bargmann space and on the Bergman space over the unit ball. Finally, we discuss the “finite rank problem”. We show that there are no non-trivial rank one Toeplitz operators Tf for f∈Sym>0(Cn). In all these problems, the growth at infinity of the symbols plays a crucial role
A calcium-dependent protease as a potential therapeutic target for Wolfram syndrome
No full textFull author list omitted for brevity. For the full list of authors, see article.Wolfram syndrome is a genetic disorder characterized by diabetes and neurodegeneration and considered as an endoplasmic reticulum (ER) disease. Despite the underlying importance of ER dysfunction in Wolfram syndrome and the identification of two causative genes, Wolfram syndrome 1 (WFS1) and Wolfram syndrome 2 (WFS2), a molecular mechanism linking the ER to death of neurons and β cells has not been elucidated. Here we implicate calpain 2 in the mechanism of cell death in Wolfram syndrome. Calpain 2 is negatively regulated by WFS2, and elevated activation of calpain 2 by WFS2-knockdown correlates with cell death. Calpain activation is also induced by high cytosolic calcium mediated by the loss of function of WFS1. Calpain hyperactivation is observed in the WFS1 knockout mouse as well as in neural progenitor cells derived from induced pluripotent stem (iPS) cells of Wolfram syndrome patients. A small-scale small-molecule screen targeting ER calcium homeostasis reveals that dantrolene can prevent cell death in neural progenitor cells derived from Wolfram syndrome iPS cells. Our results demonstrate that calpain and the pathway leading its activation provides potential therapeutic targets for Wolfram syndrome and other ER diseases
A novel mutation of WFS1 gene in a Japanese man of Wolfram syndrome with positive diabetes-related antibodies
No full textWolfram syndrome is a rare, autosomal recessive disorder characterized by early-onset diabetes mellitus, optic atrophy and neurological and endocrinological abnormalities. A 47-year-old Japanese man with frequent severe hypoglycemic episodes was diagnosed as Wolfram syndrome based on clinical features and laboratory data. He had positive glutamic acid decarboxylase (GAD) and insulinoma-associated antigen-2 (IA-2) antibodies, both uncommon in this syndrome. Genetic analysis revealed that WFS1 gene of the patient has a homozygous 5 base pairs (AAGGC) insertion at position 1279 in exon 8, causing a frameshift at codon 371 leading to premature termination at codon 443
project-aero/transient-indicators: Files associated with 2020-01-13 manuscript draft. Author correction.
No full textThe author of the Wolfram Notebook has been corrected to be S. M. O'Regan
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