A Compact Microchip-Based Atomic Clock Based on Ultracold Trapped Rb Atoms

We propose a compact atomic clock based on ultracold Rb atoms that are magnetically trapped near the surface of an atom microchip. An interrogation scheme that combines electromagnetically-induced transparency (EIT) with Ramsey's method of separated oscillatory fields can achieve atomic shot-noise level performance of 10^{-13}/sqrt(tau) for 10^6 atoms. The EIT signal can be detected with a heterodyne technique that provides noiseless gain; with this technique the optical phase shift of a 100 pW probe beam can be detected at the photon shot-noise level. Numerical calculations of the density matrix equations are used to identify realistic operating parameters at which AC Stark shifts are eliminated. By considering fluctuations in these parameters, we estimate that AC Stark shifts can be canceled to a level better than 2*10^{-14}. An overview of the apparatus is presented with estimates of duty cycle and power consumption.Comment: 15 pages, 11 figures, 5 table

A Compact and Transportable Ultracold Matter System and Progress Towards a Continuously Operating Neutral Rydberg Atom Quantum Computer

The work in this thesis falls into two broad categories: creating Bose-Einstein condensates (BECs) in compact and portable systems, and manipulating neutral atoms in small systems to facilitate a continuously running neutral Rydberg atom quantum computer. The work with BECs focused on the miniaturization of ultracold matter systems. Ultracold matter has potential uses in many practical applications, such as atomic clocks, inertial sensors, and electric and magnetic field sensing. Much of the potential of atom chip based systems relies on the ability for the system to make its way out of the lab. The BEC system created occupies a volume of 0.4m^3 and operates at a repetition rate as high as 0.3Hz, creating Rubidium BECs of around 20k atoms. The system contains all of the components needed to produce and image BECs, including the UHV system, lasers, data acquisition hardware, electronics, and imaging equipment. The system can be easily reconfigured for different applications simply by changing the atom chip. As such, the hope is that it can serve as a standardized platform for a variety of portable experiments that utilize ultracold matter. The quantum computing work focuses on the ongoing work in atom manipulation for neutral Rydberg atom quantum computing. Neutral Rydberg atom quantum computing has great potential and, by harnessing the tool kit developed working with cold atoms, has the potential of scalability and continuous operation. An entirely new laser system and vacuum cell was built to work with Cesium. We have currently built a state of the art vacuum cell and developed far-detuned optical trapping and transport techniques to facilitate continuous quantum computing. Ongoing efforts include optical lattice generation and single-atom manipulation and imaging

Root morphology and biomechanical characteristics of high altitude alpine plant species and their potential application in soil stabilization

Glacial forefields host young, poorly developed soils with highly unstable environmental conditions. Root system contribution to soil stabilization is a well-known phenomenon. Identifying the functional traits and root morphology of pioneer vegetation that establish on forefields can provide information useful in the practical application of plants in land restoration of high altitude mountain sites.This study aims to gather information on the root morphology and biomechanical characteristics of the 10 most dominant pioneer plant species of the forefield of Lys Glacier (NW Italian Alps).X-ray Computed Tomography (X-ray CT) was used to visualize and quantify non-destructively the root architecture of the studied species. Samples were cored directly from the forefield. Data on root traits such as total root length, rooting depth, root diameter, root length density and number of roots in relation to diameter classes as well as plant height were determined and compared between species. Roots were also tested for their tensile strength resistance.X-ray CT technology allowed us to visualize the 3D root architecture of species intact in their natural soil system. X-ray CT technology provided a visual representation of root-soil interface and information on the exact position, orientation and elongation of the root system in the soil core. Root architecture showed high variability among the studied species. For all species the majority of roots consisted of roots smaller than 0.5. mm in diameter. There were also considerable differences found in root diameter and total root length although these were not statistically significant. However, significant differences were found in rooting depth, root length density, plant height and root tensile strength between species and life forms (dwarf shrub, forb, graminoid). In all cases, root tensile strength decreased with increasing root diameter. The highest tensile strength was recorded for graminoids such as Luzula spicata (L.) DC. and Poa laxa Haenke and the lowest for Epilobium fleischeri Hochst.The differences in root properties among the studied species highlight the diverse adaptive and survival strategies plants employ to establish on and thrive in the harsh and unstable soil conditions of a glacier forefield. The data determined in this study could provide a significant contribution to a database that allow those who are working in land restoration and preservation of high altitude mountain sites to employ native species in a more efficient, effective and informed manner

Describing the content of trial recruitment interventions using the TIDieR Reporting Checklist : A systematic methodology review

Peer reviewe

Quail Genomics: a knowledgebase for Northern bobwhite

<p>Abstract</p> <p>Background</p> <p>The Quail Genomics knowledgebase (<url>http://www.quailgenomics.info</url>) has been initiated to share and develop functional genomic data for Northern bobwhite (<it>Colinus virginianus</it>). This web-based platform has been designed to allow researchers to perform analysis and curate genomic information for this non-model species that has little supporting information in GenBank.</p> <p>Description</p> <p>A multi-tissue, normalized cDNA library generated for Northern bobwhite was sequenced using 454 Life Sciences next generation sequencing. The Quail Genomics knowledgebase represents the 478,142 raw ESTs generated from the sequencing effort in addition to assembled nucleotide and protein sequences including 21,980 unigenes annotated with meta-data. A normalized MySQL relational database was established to provide comprehensive search parameters where meta-data can be retrieved using functional and structural information annotation such as gene name, pathways and protein domain. Additionally, blast hit cutoff levels and microarray expression data are available for batch searches. A Gene Ontology (GO) browser from Amigo is locally hosted providing 8,825 unigenes that are putative orthologs to chicken genes. In an effort to address over abundance of Northern bobwhite unigenes (71,384) caused by non-overlapping contigs and singletons, we have built a pipeline that generates scaffolds/supercontigs by aligning partial sequence fragments against the indexed protein database of chicken to build longer sequences that can be visualized in a web browser. </p> <p>Conclusion</p> <p>Our effort provides a central repository for storage and a platform for functional interrogation of the Northern bobwhite sequences providing comprehensive GO annotations, meta-data and a scaffold building pipeline. The Quail Genomics knowledgebase will be integrated with Japanese quail (<it>Coturnix coturnix</it>) data in future builds and incorporate a broader platform for these avian species. </p