Preliminary test results of a flight management algorithm for fuel conservative descents in a time based metered traffic environment

A flight management algorithm designed to improve the accuracy of delivering the airplane fuel efficiently to a metering fix at a time designated by air traffic control is discussed. The algorithm provides a 3-D path with time control (4-D) for a test B 737 airplane to make an idle thrust, clean configured descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path is calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithms and the results of the flight tests are discussed

Development and test results of a flight management algorithm for fuel conservative descents in a time-based metered traffic environment

A simple flight management descent algorithm designed to improve the accuracy of delivering an airplane in a fuel-conservative manner to a metering fix at a time designated by air traffic control was developed and flight tested. This algorithm provides a three dimensional path with terminal area time constraints (four dimensional) for an airplane to make an idle thrust, clean configured (landing gear up, flaps zero, and speed brakes retracted) descent to arrive at the metering fix at a predetermined time, altitude, and airspeed. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard pressure and temperature effects. The flight management descent algorithm is described. The results of the flight tests flown with the Terminal Configured Vehicle airplane are presented

Facebook surveillance of former romantic partners: Associations with post-breakup recovery and personal growth

Copyright @ 2012 Mary Ann Liebert, Inc.This article has been made available through the Brunel Open Access Publishing Fund.Previous research has found that continuing offline contact with an ex-romantic partner following a breakup may disrupt emotional recovery. The present study examined whether continuing online contact with an ex-partner through remaining Facebook friends and/or engaging in surveillance of the ex-partner's Facebook page inhibited postbreakup adjustment and growth above and beyond offline contact. Analysis of the data provided by 464 participants revealed that Facebook surveillance was associated with greater current distress over the breakup, more negative feelings, sexual desire, and longing for the ex-partner, and lower personal growth. Participants who remained Facebook friends with the ex-partner, relative to those who did not remain Facebook friends, reported less negative feelings, sexual desire, and longing for the former partner, but lower personal growth. All of these results emerged after controlling for offline contact, personality traits, and characteristics of the former relationship and breakup that tend to predict postbreakup adjustment. Overall, these findings suggest that exposure to an ex-partner through Facebook may obstruct the process of healing and moving on from a past relationship

Physiotherapy students\u27 perceptions and experiences of clinical prediction rules

Objectives: Clinical reasoning can be difficult to teach to pre-professional physiotherapy students due to their lack of clinical experience. It may be that tools such as clinical prediction rules (CPRs) could aid the process, but there has been little investigation into their use in physiotherapy clinical education. This study aimed to determine the perceptions and experiences of physiotherapy students regarding CPRs, and whether they are learning about CPRs on clinical placement. Design: Cross-sectional survey using a paper-based questionnaire. Participants: Final year pre-professional physiotherapy students (n=371, response rate 77%) from five universities across five states of Australia. Results: Sixty percent of respondents had not heard of CPRs, and a further 19% had not clinically used CPRs. Only 21% reported using CPRs, and of these nearly three-quarters were rarely, if ever, learning about CPRs in the clinical setting. However most of those who used CPRs (78%) believed CPRs assisted in the development of clinical reasoning skills and none (0%) was opposed to the teaching of CPRs to students. The CPRs most commonly recognised and used by students were those for determining the need for an X-ray following injuries to the ankle and foot (67%), and for identifying deep venous thrombosis (63%). Conclusions: The large majority of students in this sample knew little, if anything, about CPRs and few had learned about, experienced or practiced them on clinical placement. However, students who were aware of CPRs found them helpful for their clinical reasoning and were in favour of learning more about them

Diameter and Chirality Dependence of Exciton Properties in Carbon Nanotubes

We calculate the diameter and chirality dependences of the binding energies, sizes, and bright-dark splittings of excitons in semiconducting single-wall carbon nanotubes (SWNTs). Using results and insights from {\it ab initio} calculations, we employ a symmetry-based, variational method based on the effective-mass and envelope-function approximations using tight-binding wavefunctions. Binding energies and spatial extents show a leading dependence with diameter as $1/d$ and $d$, respectively, with chirality corrections providing a spread of roughly 20% with a strong family behavior. Bright-dark exciton splittings show a $1/d^2$ leading dependence. We provide analytical expressions for the binding energies, sizes, and splittings that should be useful to guide future experiments

Optimal Geological Environments for Carbon Dioxide Disposal in Brine Formations (Saline Aquifers) in the United States Pilot Experiment in the Frio Formation, Houston Area

This Environmental Assessment (EA) provides the results of an evaluation of the potential environmental consequences of a field experiment and injection of CO2 into a subsurface brine-bearing formation, a process known as geologic sequestration. The U.S. Department of Energy (DOE) is proposing to fund this project to determine if geologic sequestration of CO2 is safe and effective in reducing atmospheric releases, and if the sequestration process can be modeled, measured, and monitored. If approved, DOE would provide the $3.4 million cost of the project. This project was proposed by the Bureau of Economic Geology as Phase III of a DOE-initiated competitive solicitation DE-RA26-98FT35008. Phase I and Phase II assessed the optimal geological environments for geologic sequestration in brine formations in the onshore U.S., and found that the upper Texas Gulf Coast was a region with excellent potential for geologic sequestration. Phase III will test the Phase I and Phase II conclusions with a field experiment. Increasing concentrations of CO2 in the atmosphere are thought to have the potential to force change toward a warmer global climate. These changes may have negative impacts on human systems as well as ecosystems. DOE is developing an understanding of environmentally acceptable options. Geologic sequestration is one of the highly ranked technologies for stabilizing the amount of CO2 released to the atmosphere as waste from combustion of fossil fuel. In this method, CO2 is captured from a stationary industrial source of CO2, compressed, and injected into the subsurface. The injection site must be selected to have the geologic properties that will assure that the CO2 will remain trapped in the subsurface and isolated from the atmosphere for thousands of years. The natural capacity of the subsurface to trap and retain buoyant fluids such as oil and natural gas is well known. Technologies for injection of fluids into the subsurface are widely applied both for waste disposal and for enhancing recovery of oil. This field experiment is designed to closely monitor the performance of the subsurface in holding CO2. To reduce risks, the injection is designed using the minimum volume of CO2 that can be measured in the subsurface using a wide variety of techniques, and to be completed over a short period of time (less than 1 year). The results obtained from monitoring a small volume will provide assurance that in a similar geologic environment, a large volume can be safely and effectively injected and monitored over a longer time frame. Monitoring and modeling tools have been designed and will be tested at this site by researchers from Lawrence Berkeley National Laboratory (LBNL), Oak Ridge National Laboratory (ORNL), Lawrence Livermore National Laboratory (LLNL), and National Energy Technology Laboratory (NETL).Bureau of Economic Geolog

Role of parathyroid hormone in the phosphaturia of extracellular fluid volume expansion

Role of parathyroid hormone in the phosphaturia of extracellular fluid volume expansion. Acute expansion of the extracellular fluid volume increases the urinary excretion of phosphate. The present study examined the importance of increased plasma parathyroid hormone concentration in the phosphaturia accompanying acute extracellular fluid volume expansion (ECVE). Infusion of a calcium-free Ringer's solution into dogs was associated with increased urinary phosphate excretion and serum immunoreactive parathyroid hormone concentration (iPTH), the latter being significantly correlated with a decrease in plasma ionized calcium concentration. Prevention of the fall in plasma ionized calcium concentration by infusion of a calcium containing Ringer's solution prevented the increase in serum iPTH but the magnitude of the phosphaturia was not affected. The phosphaturia associated with ECVE was also not affected in thyroparathyroidectomized (TPTX) dogs which received a maintenance infusion of bovine PTH. In contrast, in acutely TPTX dogs which did not receive a maintenance infusion of PTH, the phosphaturic response to ECVE was significantly depressed. These data indicate that 1) the increase in serum iPTH concentration following ECVE is the result of a fall in plasma ionized calcium concentration, 2) the increase in phosphate excretion accompanying ECVE is not dependent on an increase in serum iPTH concentration and 3) in the presence of a low or falling serum PTH concentration, the increase in phosphate excretion can be significantly blunted.Rôle de l'hormone parathyroïdienne dans la phosphaturie consécutive à l'expansion extracellulaire. L'expansion aiguë du volume extracellulaire augmente l'excrétion urinaire du phosphate. Ce travail examine le rôle de l'augmentation de la concentration d'hormone parathyroïdienne dans la phosphaturie qui accompagne l'expansion du volume extracellulaire (ECVE). L'administration à des chiens d'une solution de Ringer sans calcium est associée à une augmentation de l'excrétion urinaire de phosphate et à une augmentation de la concentration d'hormone parathyroïdienne immunoréactive du plasma (iPTH). Cette dernière est significativement corrélée à la diminution de la concentration plasmatique du calcium ionisé. L'empêchement de la diminution de la concentration plasmatique du calcium ionisé par l'administration d'une solution de Ringer contenant du calcium évite l'augmentation de iPTH dans le plasma mais n'affecte pas l'importance de la phosphaturie. La phosphaturie associée à ECVE n'est pas non plus modifiée chez des chiens thyroparathyroïdectomisés (TPTX) qui reçoivent une perfusion de PTH bovine. Au contraire chez des chiens TPTX aigus qui ne reçoivent pas de perfusion de PTX la réponse à ECVE est significativement diminuée. Ces résultats indiquent que 1) L'augmentation de iPTH du plasma après ECVE est la conséquence d'une diminution de la concentration plasmatique du calcium ionisé, 2) l'augmentation de l'excrétion du phosphate qui accompagne ECVE ne dépend pas de l'augmentation de iPTH du plasma et 3) quand la concentration plasmatique de PTH est faible ou en voie de diminution, l'augmentation de l'excrétion de phosphate peut être significativement masquée

Theory of excitons in cubic III-V semiconductor GaAs, InAs and GaN quantum dots: fine structure and spin relaxation

Exciton fine structures in cubic III-V semiconductor GaAs, InAs and GaN quantum dots are investigated systematically and the exciton spin relaxation in GaN quantum dots is calculated by first setting up the effective exciton Hamiltonian. The electron-hole exchange interaction Hamiltonian, which consists of the long- and short-range parts, is derived within the effective-mass approximation by taking into account the conduction, heavy- and light-hole bands, and especially the split-off band. The scheme applied in this work allows the description of excitons in both the strong and weak confinement regimes. The importance of treating the direct electron-hole Coulomb interaction unperturbatively is demonstrated. We show in our calculation that the light-hole and split-off bands are negligible when considering the exciton fine structure, even for GaN quantum dots, and the short-range exchange interaction is irrelevant when considering the optically active doublet splitting. We point out that the long-range exchange interaction, which is neglected in many previous works, contributes to the energy splitting between the bright and dark states, together with the short-range exchange interaction. Strong dependence of the optically active doublet splitting on the anisotropy of dot shape is reported. Large doublet splittings up to 600 $\mu$eV, and even up to several meV for small dot size with large anisotropy, is shown in GaN quantum dots. The spin relaxation between the lowest two optically active exciton states in GaN quantum dots is calculated, showing a strong dependence on the dot anisotropy. Long exciton spin relaxation time is reported in GaN quantum dots. These findings are in good agreement with the experimental results.Comment: 22+ pages, 16 figures, several typos in the published paper are corrected in re

Constraining Large Scale Structure Theories with the Cosmic Background Radiation

We review the relevant 10+ parameters associated with inflation and matter content; the relation between LSS and primary and secondary CMB anisotropy probes; COBE constraints on energy injection; current anisotropy band-powers which strongly support the gravitational instability theory and suggest the universe could not have reionized too early. We use Bayesian analysis methods to determine what current CMB and CMB+LSS data imply for inflation-based Gaussian fluctuations in tilted $\Lambda$CDM, $\Lambda$hCDM and oCDM model sequences with age 11-15 Gyr, consisting of mixtures of baryons, cold (and possibly hot) dark matter, vacuum energy, and curvature energy in open cosmologies. For example, we find the slope of the initial spectrum is within about 5% of the (preferred) scale invariant form when just the CMB data is used, and for $\Lambda$CDM when LSS data is combined with CMB; with both, a nonzero value of $\Omega_\Lambda$ is strongly preferred ($\approx 2/3$ for a 13 Gyr sequence, similar to the value from SNIa). The $o$CDM sequence prefers $\Omega_{tot}<1$, but is overall much less likely than the flat $\Omega_\Lambda \ne 0$ sequence with CMB+LSS. We also review the rosy forecasts of angular power spectra and parameter estimates from future balloon and satellite experiments when foreground and systematic effects are ignored.Comment: 20 pages, LaTeX, 5 figures, 2 tables, uses rspublic.sty To appear in Philosophical Transactions of the Royal Society of London A, 1998. "Discussion Meeting on Large Scale Structure in the Universe," Royal Society, London, March 1998. Text and colour figures also available at ftp://ftp.cita.utoronto.ca/bond/roysoc9