Requirement of optical coherence for continuous-variable quantum teleportation

We show that the sender (Alice) and the receiver (Bob) each require coherent devices in order to achieve unconditional continuous variable quantum teleportation (CVQT), and this requirement cannot be achieved with conventional laser sources, even in principle. The appearance of successful CVQT in recent experiments is due to interpreting the measurement record fallaciously in terms of one preferred ensemble (or decomposition) of the correct density matrix describing the state. Our analysis is unrelated to technical problems such as laser phase drift or finite squeezing bandwidth.Comment: One figure in eps forma

Pleistocene and Halocene Remains from the Red River, Southwest Arkansas

Vertebrate remains have been found on gravel bars of the Red River in southwest Arkansas, northeast Louisiana, and east Texas. The majority of these specimens were recovered by amateur archaeologists and Dr. Frank Schambach of the Arkansas Archaeology Survey. Extinct species of bison (Bison sp.), mastodon (Mammut americanum), pampathere (Holmesina septentrionalis), llama (Palaeolama mirifica), tortoises (Geochelone sp.), and (Terrapene sp.) indicate a Pleistocene component in the region\u27s alluvium. The giant tortoise, pampathere, and llama represent first known occurrences of these species for the state of Arkansas. Search times between finds were recorded for seven localities. The richest gravel bar averaged one man-minute per find. The least productive bar averaged 82.5 man-minutes per find. The average collection rate for all bars was one find per 19.5 man-minutes

Space Launch System Mission Flexibility Assessment

The Space Launch System (SLS) is envisioned as a heavy lift vehicle that will provide the foundation for future beyond low Earth orbit (LEO) missions. While multiple assessments have been performed to determine the optimal configuration for the SLS, this effort was undertaken to evaluate the flexibility of various concepts for the range of missions that may be required of this system. These mission scenarios include single launch crew and/or cargo delivery to LEO, single launch cargo delivery missions to LEO in support of multi-launch mission campaigns, and single launch beyond LEO missions. Specifically, we assessed options for the single launch beyond LEO mission scenario using a variety of in-space stages and vehicle staging criteria. This was performed to determine the most flexible (and perhaps optimal) method of designing this particular type of mission. A specific mission opportunity to the Jovian system was further assessed to determine potential solutions that may meet currently envisioned mission objectives. This application sought to significantly reduce mission cost by allowing for a direct, faster transfer from Earth to Jupiter and to determine the order-of-magnitude mass margin that would be made available from utilization of the SLS. In general, smaller, existing stages provided comparable performance to larger, new stage developments when the mission scenario allowed for optimal LEO dropoff orbits (e.g. highly elliptical staging orbits). Initial results using this method with early SLS configurations and existing Upper Stages showed the potential of capturing Lunar flyby missions as well as providing significant mass delivery to a Jupiter transfer orbit

Managing rental car businesses in the new economy: Using a multivariate decision model approach

U.S. rental car organizations are having to modify their business models to adapt to the new economy, which includes increased fuel costs, reduced business and leisure travel, and reduced resale of low mileage rental units. Revenue is negatively impacted due to increased maintenance as a result of higher mileage requirements placed on the rental inventory. Changes in the depreciation allowance on the rental car fleet reduced the potential value of vehicles by requiring fleet operations managers to maintain the fleets for longer periods of time. This article presents a multivariate decision-making model, which used in conjunction with in-house performance indicators, will assist operations managers in understanding specific variables likely to impact rental car revenues and optimize their decisions regarding available assets

The Impact Of Lecture Capture On Student Performance In Business Courses

This paper examines the effect of the e-learning technology of lecture capture on the performance of undergraduate business students in business law, economics, finance, and management courses. The sample consists of 890 student observations at a midsized regional institution located in the Southwestern region of the United States. The dependent variable is percentage score on a comprehensive final exam in advanced business courses. The empirical model controls for effort, grade point average, standardized test scores (SAT/ACT), and instruction mode. Demographic variables are gender, ethnic background, age, major, and transfer students. Effort measured via homework score, grade point average, ability measured via standardized test scores, academic major, and access to lecture capture are the five model variables that are positive and statistically significant. Age, classification as a transfer student, and online courses without lecture capture are the three statistically significant variables with a negative coefficient. The demographic variables associated with African-American, Hispanic, and gender are not statistically significant determinants of performance on the final exams. The results indicate that students completing business courses with access to lecture capture score approximately three percent higher on the final exam, holding other factors constant

Particle Size Distributions Measured in the B757 Engine Plume During EXCAVATE

The Experiment to Characterize Aircraft Volatile Aerosols and Trace Species Emissions (EXCAVATE) took place at NASA Langley Research Center during January 2002. This ground based study was conducted to examine the role of fuel sulfur content on particulate emissions. Size distributions as a function of engine operating conditions were measured in the exhaust plume of a B-757 at four downstream axial locations (1 m, 10 m, 25 m and 35 m). The engine was run on JP-5 with three different sulfur concentrations, 810 ppm, 1050 ppm, 1820 ppm; and was operated over a range of power settings from idle to near-full power. Zalabsky differential-mobility analyzers DMAS), Met One condensation-nuclei counters (CNCs), and a TSI 3022 condensation-particle counter (CPC) were used to measure the size distributions. The total number-count (particle concentration), number-based Emissions Index (EInumber) and mass-based Emissions Index (E1-J increased with fuel sulfur-content and engine pressure ratio (EPR). Count Mean Diameter (Ch4D) also increased with EPR yet remained fairly constant with fuel sulfur-content for a fixed location in the exhaust plume. Also the mode and CMD both increased with distance in the plume

Enhanced Feasibility Assessment of Payload Adapters for NASAs Space Launch System

The first flight of NASAs new exploration-classlaunch vehicle, the Space Launch System (SLS), will test amyriad of systems designed to enable the next generation of deepspace human spaceflight, and launch from Kennedy SpaceCenter no earlier than December 2019. The initial Block 1configuration for EM-1 will be capable of lofting at least 70metric tons (t) of payload and send the Orion crew vehicle intoa distant retrograde lunar orbit, paving the way for future crewmissions to cislunar space and eventually Mars. A Block 1Bversion of SLS will lift at least 34 t to trans-lunar injection (TLI)in its crew configuration and at least 37 t to TLI in its cargoconfiguration no earlier than 2024. For Mars-class payloads,larger fairings and payload adapters for the Block 2 cargovehicle are under consideration. For missions beyond the Earth-Moon system, SLS offers greater characteristic energy (C3)than any other launch vehicle, enabling shorter transit times orheavier payloads with more robust science packages formissions to the outer solar system. Indeed, the unmatchedcombination of thrust, payload volume and departure energythat SLS provides opens new opportunities for human androbotic exploration of deep space