High School to College Transition Initiatives: Making it a Reality

The challenge continues for both secondary and post-secondary institutions to help high school students successfully transition to college. High school and college librarians share common goals with teaching faculty in helping students succeed and include improving college students’ first-year experience as well as fostering lifelong learning. One step towards bridging this gap is for librarians to work together with their constituencies in improving students’ information literacy skills. Historically, librarians at Reynolds Community College in Richmond, VA have collaborated with high school librarians and teachers in the Richmond area on an ad hoc basis upon request. Most recently, Reynolds librarians have partnered up on several ongoing collaborative initiatives to help prepare students for college level research and are striving towards developing a more formal and sustainable plan for collaboration. This presentation will outline these various initiatives including: working with Reynolds Advanced College Academy (ACA) coordinators to plan a mobile library scavenger hunt and workshop for ACA students; presenting a workshop to ACA faculty on Reynolds Library resources & services; working with dual enrollment English teaching faculty and high school media specialists to provide workshops to dual enrollment English students; and working with a high school media specialist to plan and present an orientation session for all senior English classes on what to expect from college libraries and research. Future plans for ongoing collaboration will also be discussed

Silkswap: An asymmetric automated market maker model for stablecoins

Silkswap is an automated market maker model designed for efficient stablecoin trading with minimal price impact. The original purpose of Silkswap is to facilitate the trading of fiat-pegged stablecoins with the stablecoin Silk, but it can be applied to any pair of stablecoins. The Silkswap invariant is a hybrid function that generates an asymmetric price impact curve. We present the derivation of the Silkswap model and its mathematical properties. We also compare different numerical methods used to solve the invariant equation. Finally, we compare our model with the well-known Curve Finance model

Mikrosystemtechnisch integriertes, optisch gepumptes Magnetometer

Die vorliegende Arbeit beinhaltet unterschiedliche Aspekte von Entwurf, Fertigung und Erforschung mikrofabrizierter Alkalidampfzellen. Alkalidampfzellen, also hermetisch versiegelte Volumina gefüllt mit Atomen eines Alkalimetalls, haben besondere Bedeutung als zentrales Element innerhalb von optisch gepumpten Magnetometern (OPM) sowie von kleinformatigen Frequenzstandards (bzw. Atomuhren). Moderne Entwicklungen in diesem Bereich gehen insbesondere zu einer Verringerung des Volumens bzw. der Größe der verwendeten Bauteile, da dies zum einen die bessere Integrierbarkeit der Sensoren gewährleistet und außerdem Probleme bei Messungen in inhomogenen Magnetfeldern (z.B. bei der Verwendung im Erdmagnetfeld) vermeidet bzw. beschränkt. Die Verringerung des Zellvolumens widerspricht jedoch gleichzeitig der Forderung an eine hohe Empfindlichkeit der Messung. Diesem aufkommenden Widerspruch zum einen, sowie dem mikrosystemtechnischen Fertigungsprozess der Zellen zum anderen ist diese Arbeit gewidmet. Hinsichtlich des Fertigungsprozesses werden Entwicklungen für die Handhabung des hier verwendeten, hochreaktiven Cäsiums sowie die Möglichkeit zur Passivierung des Zellkörpers mit dünnen Schichten aus Al2O3 , abgeschieden mittels Atomlagenabscheidung, gegen den Einfluss des verwendeten Cäsiums vorgestellt. Hervorzuheben ist eine für den hermetischen Zellverschluss entwickelte Methode, welche anodisches Bonden bei Raumtemperatur und Spannungen im Bereich von 100V erlaubt. Diese einzigartige Parameterkombination wird durch die Verwendung dünner Schichten eines lithiumhaltigen Glases mit hoher Ionenleitfähigkeit ermöglicht. Das Ergebnis dieser Arbeit besteht in einem Array aus mehreren Alkalidampfzellen, welche über Kanäle mit einer zentralen Struktur, dem Reservoir, verbunden sind. Das Reservoir dient der Aufnahme des Cäsiums. Der Aufbau des Arrays gewährleistet identische Eigenschaften bzw. Charakteristika der einzelnen Zellen. Insbesondere durch Anpassungen des verwendeten Puffergases sowie des in den Zellen herrschenden Puffergasdrucks konnte die erreichbare schrotrauschbegrenzte Empfindlichkeit der hergestellten Zellen auf Werte von ca. 150fT/ √ Hz gesteigert werden. Bringt man diesen Wert in Relation zum Zellvolumen von 50mm 3 ergibt sich für die Zellen ein Wert von 33,6 fTcm3/2 / √ Hz. Dieser stellt für Messungen im verwendeten Arbeitsregime international einen Spitzenwert dar.The present work includes different aspects of the design, fabrication and research of microfabricated atomic vapor cells. Atomic vapor cells, corresponding to hermetically sealed volumes filled with atoms of the alkali metals, have a special importance as the central element of optically pumped magnetometers (OPM) and for small frequency standards (atomic clocks respectively). Modern developments in optical magnetometry are pointing in particular to a reduction of the size and volume of the devices used. The objective of this is to achieve a better integrability of the sensors but also to prevent problems, connected with measuring in inhomogeneous magnetic fields (for instance during the application of the sensor in the earth’s magnetic field). The reduction of the cell volume counters the demand on a high resolution of the measurement, however. This work is devoted to the mentioned contradiction of using atomic vapor cells with reduced volumes on the one hand and to the fabrication process of those cells based on microsystem technology on the other. With regards to the fabrication process a new development for the handling of the highly reactive alkali metal (cesium) is presented. To prevent bothering interactions of the cesium with the cell’s body, a technique to passivate the cell walls with ultra-thin layers of Al2O3 , deposit by atomic layer deposition, is introduced. Special emphasis should be placed on a method to seal the vapor cells hermetically with an adapted anodic bonding process, carried out at room temperature and with voltages of about 100V. This unique combination in the process parameters is enabled by the application of thin, highly ion-conductive, lithium containing glass layers. The final result of this work is an array of several atomic vapor cells, connected via canals to a central structure. This so-called reservoir is used to gather the metallic cesium. The structure of this setup guarantees identical characteristics of each cell during the measurements. By adjustments of the type and especially the pressure of the buffer gas used, the shot-noise-limited sensitivity of the cells fabricated here was enhanced to values of about 150fT/ √ Hz. In relation to the cell’s volume of 50mm3 it follows a sensitivity of about 33.6 fTcm3/2 / √ Hz. With regard to the used working regime this is a peak value compared with values published to date

Assessing Learning in Information Literacy: Impetus, Implementation, and Impact

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An optically pumped magnetometer working in the light-shift dispersed Mz mode

We present an optically pumped magnetometer working in a new operational mode— the light-shift dispersed Mz (LSD-Mz) mode. It is realized combining various features; (1) high power off-resonant optical pumping; (2) Mz configuration, where pumping light and magnetic field of interest are oriented parallel to each other; (3) use of small alkali metal vapor cells of identical properties in integrated array structures, where two such cells are pumped by circularly polarized light of opposite helicity; and (4) subtraction of the Mz signals of these two cells. The LSD-Mz magnetometer’s performance depends on the inherent and very complex interplay of input parameters. In order to find the configuration of optimal magnetometer resolution, a sensitivity analysis of the input parameters by means of Latin Hypercube Sampling was carried out. The resulting datasets of the multi-dimensional parameter space exploration were assessed by a subsequent physically reasonable interpretation. Finally, the best shot-noise limited magnetic field resolution was determined within that parameter space. As the result, using two 50 mm3 integrated vapor cells a magnetic field resolution below 10 fT/√Hz at Earth’s magnetic field strength is possible