Inter-sensory Judgments of Signal Duration

Intersensory discrimination of signal duration using visual and auditory signal

Theory of Electron-Phonon Dynamics in Insulating Nanoparticles

We discuss the rich vibrational dynamics of nanometer-scale semiconducting and insulating crystals as probed by localized electronic impurity states, with an emphasis on nanoparticles that are only weakly coupled to their environment. Two principal regimes of electron-phonon dynamics are distinguished, and a brief survey of vibrational-mode broadening mechanisms is presented. Recent work on the effects of mechanical interaction with the environment is discussed.Comment: Revte

Central electrical utility power for a satellite ring city in low earth orbit space

Information is given in viewgraph form on central electrical power for a satellite ring city, defined as a group of large free flyers of 10 to 20 units with perhaps 100 people in each unit, and organized in a circle so that power can be fed from a central location. The free flyers would be located at 300 to 700 miles in altitude, and spaced about a kilometer apart. Potential activities of a ring city are listed as well as the electrical power needs. Information is given on costs and individual and centralized solar arrays and nuclear reactor systems

Fixed base simulator study of an externally blown flap STOL transport airplane during approach and landing

A fixed-base simulator study was conducted to determine the flight characteristics of a representative STOL transport having a high wing and equipped with an external-flow jet flap in combination with four high-bypass-ratio fan-jet engines during the approach and landing. Real-time digital simulation techniques were used. The computer was programed with equations of motion for six degrees of freedom and the aerodynamic inputs were based on measured wind-tunnel data. A visual display of a STOL airport was provided for simulation of the flare and touchdown characteristics. The primary piloting task was an instrument approach to a breakout at a 200-ft ceiling with a visual landing

Ozone exchange within and above an irrigated Californian orchard

In this study, the canopy effects on the vertical ozone exchange within and above Californian orchard are investigated. We examined the comprehensive dataset obtained from the Canopy Horizontal Array Turbulence Study (CHATS). CHATS typifies a rural central Californian site, with O3 mixing ratios of less than 60 ppb and moderate NOx mixing ratios. The CHATS campaign covered a complete irrigation cycle, with our analysis including periods before and after irrigation. Lower O3 mixing ratios were found following irrigation, together with increased wind speeds, decreased air temperatures and increased specific humidity. Friction velocity, sensible heat and gas fluxes above the canopy were estimated using variations on the flux-gradient method, including a method which accounts for the roughness sublayer (RSL). These methods were compared to fluxes derived from observed eddy diffusivities of heat and friction velocity. We found that the use of the RSL parameterization, which accounts for the canopy-induced turbulent mixing above the canopy, resulted in a stronger momentum, heat, and ozone exchange fluxes above this orchard, compared to the method which omits the RSL. This was quantified by the increased friction velocity, heat flux and ozone deposition flux of up to 12, 29, and 35% at 2.5 m above the canopy, respectively. Within the canopy, vertical fluxes, as derived from local gradients and eddy diffusivity of heat, were compared to fluxes calculated using the Lagrangian inverse theory. Both methods showed a presence of vertical flux divergence of friction velocity, heat and ozone, suggesting that turbulent mixing was inefficient in homogenizing the effects driven by local sources and sinks on vertical exchange of those quantities. This weak mixing within the canopy was also corroborated in the eddy diffusivities of friction velocity and heat, which were calculated directly from the observations. Finally, the influence of water stress on the O3 budget was examined by comparing the results prior and after the irrigation. Although the analysis is limited to the local conditions, our in situ measurements indicated differences in the O3 mixing ratio prior and after irrigation during CHATS. We attribute these O3 mixing ratio changes to enhanced biological emission of volatile organic compounds (VOCs), driven by water stress

Direct current measurements of the SPIDER beam: a comparison to existing beam diagnostics

For negative ion beam sources there are several methods of measuring the accelerated beam current, most commonly electrical measurements at the power supply and calorimetric measurements. On SPIDER, the ITER Heating Neutral Beam full-scale beam source prototype, electrical measurements at the acceleration grid power supply (AGPS) are complemented by polarizing the diagnostic calorimeter STRIKE to provide an additional electrical measurement of the accelerated current. This is in addition to the calorimetric measurements provided by STRIKE. These diagnostics give differing measurements of the beam current. Exploiting the reduced number of open apertures on SPIDER a new beam diagnostic has been installed to measure the individual beamlet currents directly. The so called Beamlet Current Monitor (BCM) has been used to measure the current of five beamlets during the most recent SPIDER campaign. This work compares the BCM current to the electrical measurements at the AGPS and STRIKE. The average BCM current agrees well with the STRIKE electrical measurements, indicating that the AGPS overestimates the beam current. The individual beamlets are compared to the STRIKE calorimetric measurements, showing similar current trends with the source parameters

Re-entrance of the metallic conductance in a mesoscopic proximity superconductor

We present an experimental study of the diffusive transport in a normal metal near a superconducting interface, showing the re-entrance of the metallic conductance at very low temperature. This new mesoscopic regime comes in when the thermal coherence length of the electron pairs exceeds the sample size. This re-entrance is suppressed by a bias voltage given by the Thouless energy and can be strongly enhanced by an Aharonov Bohm flux. Experimental results are well described by the linearized quasiclassical theory.Comment: improved version submitted to Phys. Rev. lett., 4 pages, 5 included epsf figure

Photothermal Absorption Spectroscopy of Individual Semiconductor Nanocrystals

Photothermal heterodyne detection is used to record the first room-temperature absorption spectra of single CdSe/ZnS semiconductor nanocrystals. These spectra are recorded in the high cw excitation regime, and the observed bands are assigned to transitions involving biexciton and trion states. Comparison with the single nanocrystals photoluminescence spectra leads to the measurement of spectral Stokes shifts free from ensemble averaging

Does the PI3K pathway promote or antagonize regulatory T cell development and function?

Regulatory T cells (Tregs) prevent autoimmunity and inflammation by suppressing the activation of other T cells and antigen presenting cells. The role of phosphoinositide 3-kinase (PI3K) signaling in Treg is controversial. Some studies suggest that inhibition of the PI3K pathway is essential for the development of Tregs whereas other studies have shown reduced Treg numbers and function when PI3K activity is suppressed. Here we attempt to reconcile the different studies that have explored PI3K and the downstream effectors Akt, Foxo, and mTOR in regulatory T cell development and function and discuss the implications for health and therapeutic intervention

A Medial Congruent Polyethylene Offers Satisfactory Early Outcomes and Patient Satisfaction in Total Knee Arthroplasty

Background Although a successful operation, almost 20% of patients are dissatisfied with total knee arthroplasty (TKA). The purpose of this retrospective cohort study was to see if a medial congruent (MC) polyethylene would offer satisfactory early outcomes and patient satisfaction after TKA. Methods We reviewed prospectively collected data on 327 TKAs using multiple bearings within the same implant system. Ninety-six received an MC bearing, 70 received a cruciate-retaining (CR) bearing, and 161 received a posterior-stabilized (PS) bearing. We evaluated the visual analog scale pain scores and range of motion (ROM) at 2 weeks, 6 weeks, 3 months, and 1 year; Patient-Reported Outcomes Measurement Information System (PROMIS-10) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) at 3 months and 1 year; and Forgotten Joint Score (FJS-12) at 1 year. Results All groups had similar KOOS and PROMIS-10 scores. MC knees had lower visual analog scale scores than PS knees at all time points (P \u3c .05) and a higher ROM than PS at 2 weeks (98.6 vs 93.7, P = .002). MC knees had a significantly higher FJS-12 than CR knees (71.6 vs 58.7, P = .02). More MC knees were “very satisfied” than CR (92.6% vs 81.5%, P = .04). Fewer MC knees were “not at all satisfied” than CR (1.2% vs 9.2%, P = .04). There were similar satisfaction ratings with MC and PS. Conclusions An MC bearing provided similar or improved early pain, ROM, KOOS, PROMIS-10, FJS-12, and patient satisfaction as compared with standard bearings in TKA