Application of optical single-sideband laser in Raman atom interferometry

A frequency doubled I/Q modulator based optical single-sideband (OSSB) laser system is demonstrated for atomic physics research, specifically for atom interferometry where the presence of additional sidebands causes parasitic transitions. The performance of the OSSB technique and the spectrum after second harmonic generation are measured and analyzed. The additional sidebands are removed with better than 20 dB suppression, and the influence of parasitic transitions upon stimulated Raman transitions at varying spatial positions is shown to be removed beneath experimental noise. This technique will facilitate the development of compact atom interferometry based sensors with improved accuracy and reduced complexity

Estudios críticos sobre genocidio

Durante las dos últimas décadas, el campo interdisciplinario de los estudios sobre genocidio se ha expandido y ha madurado drásticamente. No más a la sombra de los estudios sobre el Holocausto, ahora es el tema principal de revistas académicas, libros, enciclopedias, artículos especializados, bibliografías, talleres de trabajo, seminarios, conferencias, sitios Web, centros de investigación, agencias gubernamentales, organizaciones no gubernamentales, organizaciones internacionales y una unidad en las Naciones Unidas. Si bien no termina de estar completamente teorizada aún, la disciplina se caracteriza por un gran número de debates y enfoques. Ahora que los contornos del campo emergen más claramente es el tiempo indicado para comprometerse en reflexiones críticas sobre el estado de la cuestión (el campo) o lo que puede ser llamado estudios críticos sobre genocidio. El objetivo no es ser críticos en un sentido negativo sino considerar, mientras un canon se va definiendo, qué es dicho y qué no dicho, quiénes tienen voz y quiénes son silenciados, y cómo estas cuestiones pueden ser enlazadas con los problemas sobre el poder y el conocimiento. Es, en otras palabras, un llamado al pensamiento crítico en el campo mismo de estudios sobre genocidio, explorando nuestros supuestos, descentrando nuestros prejuicios y echando luz sobre puntos ciegos, con la esperanza de seguir enriqueciendo este dinámico campo

Potential Neutrino Signals from Galactic Gamma-Ray Sources

The recent progress made in Galactic gamma-ray astronomy using the High Energy Stereoskopic System (H.E.S.S.) instrument provides for the first time a population of Galactic TeV gamma-rays, and hence potential neutrino sources, for which the neutrino flux can be estimated. Using the energy spectra and source morphologies measured by H.E.S.S., together with new parameterisations of pion production and decay in hadronic interactions, we estimate the signal and background rates expected for these sources in a first-generation water Cherenkov detector (ANTARES) and a next-generation neutrino telescope in the Mediterranean Sea, KM3NeT, with an instrumented volume of 1 km^3. We find that the brightest gamma-ray sources produce neutrino rates above 1 TeV, comparable to the background from atmospheric neutrinos. The expected event rates of the brightest sources in the ANTARES detector make a detection unlikely. However, for a 1 km^3 KM3NeT detector, event rates of a few neutrinos per year from these sources are expected, and the detection of individual sources seems possible. Although generally these estimates should be taken as flux upper limits, we discuss the conditions and type of gamma-ray sources for which the neutrino flux predictions can be considered robust.Comment: 20 pages, 4 figures; v2: ERROR in energy scale of KM3NeT effective neutrino area corrected which resulted in event rates being about a factor 3 too low; v3: grammatical changes and update of references after receiving proof

Moe the Monkey: A Fun Way to Educate Children

This paper presents the development and usability testing of Evoke, an interactive avatar that can see, hear and respond to children in pitch-altered voice in real-time. The system uses Moe, a stylised monkey, as an interaction point between the teacher and children. Children remained fully engaged, responded more openly, and friendlier to the avatar (Moe), which was controlled by their teacher in a separate room. The user testing showed that the children listened to the character and were eager to ask questions, they grabbed and retained information given by Moe

Synthesis and characterization of biodegradable lignin nanoparticles with tunable surface properties

Lignin nanoparticles can serve as biodegradable carriers of biocidal actives with minimal environmental footprint. Here we describe the colloidal synthesis and interfacial design of nanoparticles with tunable surface properties using two different lignin precursors, Kraft (Indulin AT) lignin and Organosolv (high-purity lignin). The green synthesis process is based on flash precipitation of dissolved lignin polymer, which enabled the formation of nanoparticles in the size range of 45–250 nm. The size evolution of the two types of lignin particles is fitted on the basis of modified diffusive growth kinetics and mass balance dependencies. The surface properties of the nanoparticles are fine-tuned by coating them with a cationic polyelectrolyte, poly(diallyldimethylammonium chloride). We analyze how the colloidal stability and dispersion properties of these two types of nanoparticles vary as a function of pH and salinities. The data show that the properties of the nanoparticles are governed by the type of lignin used and the presence of polyelectrolyte surface coating. The coating allows the control of the nanoparticles’ surface charge and the extension of their stability into strongly basic regimes, facilitating their potential application at extreme pH conditions

Foreward and Preface to Courier, Volume XXVI, Number 2, Fall 1991

IT WAS THE experiences of World War II that made me, along with others, realize that if peace were to be maintained we would need a more enlightened citizenry, more people qualified in the occupations and professions, and more understanding of the international scene. During the war it had become apparent that adults, under great pressure and in short periods of time, could learn how to rivet (Rosie the Riveter!), how to speak new languages, how to operate the machines of war, and how to become leaders. Clearly, adult men and women could learn \u27new tricks\u27. They could acquire the knowledge and skills appropriate to peacetime. To help make this possible, I committed myself to the development of the field of adult education

Prevalence of Pretransition Disordering in the Rutile-to-Cacl2 Phase Transition of Geo2

The ability to tailor a material\u27s electronic properties using density driven disordering has emerged as a powerful route to materials design. The observation of anomalous structural and electronic behavior in the rutile to CaCl2 phase transition in SnO2 led to the prediction that such behavior is inherent to all oxides experiencing such a phase transition sequence [Smith et al., J. Phys. Chem. Lett. 10, 5351 (2019)1948-718510.1021/acs.jpclett.9b01633]. Here, the ultrawide band gap semiconductor GeO2 is confirmed to exhibit anomalous behavior during the rutile to CaCl2 phase transition. A phase pure rutile GeO2 sample synthesized under high-pressure, high-temperature conditions is probed using synchrotron diffraction and x-ray and optical spectroscopy under high pressure conditions. Density functional theory calculations show that the enthalpic barrier to displacing an oxygen along the B1g librational mode decreases with pressure leading up to the rutile to CaCl2 phase transition. The band structure of the distorted state shows that such oxygen displacements form small polarons