Wind-tunnel investigation of basic aerodynamic characteristics of a supercritical-wing research airplane configuration

Transonic pressure tunnel and transonic tunnel tests were performed to determine the aerodynamic characteristics of a 0.087 scale model of a supercritical wing research airplane configuration at Mach numbers from 0.25 to 1.30. The investigation included tests to determine the basic longitudinal aerodynamic characteristics, the lateral-directional aerodynamic characteristics for sideslip angles of 0 deg and + or - 2.5 deg, and the effects of Reynolds number and aeroelasticity

The NASA supercritical-wing technology

A number of high aspect ratio supercritical wings in combination with a representative wide body type fuselage were tested in the Langley 8 foot transonic pressure tunnel. The wing parameters investigated include aspect ratio, sweep, thickness to chord ratio, and camber. Subsequent to these initial series of tests, a particular wing configuration was selected for further study and development. Tests on the selected wing involved the incorporation of a larger inboard trailing edge extension, an inboard leading edge extension, and flow through nacelles. Range factors for the various supercritical wing configurations are compared with those for a reference wide body transport configuration

Drive mechanism for production of simulated human breath

Simulated breath drive mechanism was developed as subsystem to breathing metabolic simulator. Mechanism reproduces complete range of human breath rate, breath depth, and breath waveform, as well as independently controlled functional residual capacity. Mechanism was found capable of simulating various individual human breathing characteristics without any changes of parts

The Effect of Recombinant Bovine Somatotropin on Patterns of Milk Production, Lactational Milk Estimates and Net Farm Income

Bovine somatoropin (bST) alters total milk production and production patterns in dairy cows and understanding the economic benefits of bST for the dairy producer are critical. Holstein cows (n = 555) from four Michigan dairy farms were randomly assigned as untreated controls or to receive 500 mg of bovine somatotropin (PosilacR) administered every 14 days beginning at 63 to 69 days of lactation and continuing until approximately 21 days prior to the end of lactation or until the animal was removed from the herd. Average peak milk production was 50.8 kg / day and occurred at an average of 113 9 days of lactation for bST-treated cows while average peak production was 48.9 kg / day occurring at an average of 86.4 days of lactation for control cows; both parameters were significantly greater for bST-treated cows compared to controls. Study cows treated with bST were significantly more persistent in lactation (7% greater lactational persistency) compared to control cows. All DHIA estimates and actual milk produced were not significantly different between the study treatment groups for any of the four comparisons made (first, second, third monthly tests after bST treatment initiation and final (305-day) DHIA production estimates); however, the accuracy of DHIA production estimates was significantly affect by the amount of time elapsed since bST but became non-significant by the third DHIA test date. The use of bST changed NFI for each of the four study farms by $96.21,$3.57, $78.71 and ($7.15) per bST-treated cow, respectively during the trial period (from 63 to 305 days of lactation). The overall average change in NFI attributable to bST was $43.01 per bST-treated cow. 2 Profitability of bST use was observed to be quite variable between farms studied because many factors were found to affect the change in NFI per cow resulting from bST use; the level of production response and the price received for milk had the largest effects on the change in NFI associated with bST use; by contrast, price paid for bST itself and feed had only minimal effects on bST-associated profitability. Diseases that may be associated with bST may reduce the profitability of this product and need to be considered as a cost of bST use if present.bovine somatotropin, dairy, net farm income, Farm Management, Livestock Production/Industries, Productivity Analysis, Research and Development/Tech Change/Emerging,

Motion adaptation and attention: A critical review and meta-analysis

The motion aftereffect (MAE) provides a behavioural probe into the mechanisms underlying motion perception, and has been used to study the effects of attention on motion processing. Visual attention can enhance detection and discrimination of selected visual signals. However, the relationship between attention and motion processing remains contentious: not all studies find that attention increases MAEs. Our meta-analysis reveals several factors that explain superficially discrepant findings. Across studies (37 independent samples, 76 effects) motion adaptation was significantly and substantially enhanced by attention (Cohen's d = 1.12, p < .0001). The effect more than doubled when adapting to translating (vs. expanding or rotating) motion. Other factors affecting the attention-MAE relationship included stimulus size, eccentricity and speed. By considering these behavioural analyses alongside neurophysiological work, we conclude that feature-based (rather than spatial, or object-based) attention is the biggest driver of sensory adaptation. Comparisons between naïve and non-naïve observers, different response paradigms, and assessment of 'file-drawer effects' indicate that neither response bias nor publication bias are likely to have significantly inflated the estimated effect of attention

Three-dimensional Binary Superlattices of Oppositely-charged Colloids

We report the equilibrium self-assembly of binary crystals of oppositely-charged colloidal microspheres at high density. By varying the magnitude of the charge on near equal-sized spheres we show that the structure of the binary crystal may be switched between face-centered cubic, cesium chloride and sodium chloride. We interpret these transformations in terms of a competition between entropic and Coulombic forces

Particle-particle and quasiparticle random phase approximations: Connections to coupled cluster theory

We establish a formal connection between the particle-particle (pp) random phase approximation (RPA) and the ladder channel of the coupled cluster doubles (CCD) equations. The relationship between RPA and CCD is best understood within a Bogoliubov quasiparticle (qp) RPA formalism. This work is a follow-up to our previous formal proof on the connection between particle-hole (ph) RPA and ring-CCD. Whereas RPA is a quasibosonic approximation, CC theory is a correct bosonization in the sense that the wavefunction and Hilbert space are exactly fermionic. Coupled cluster theory achieves this goal by interacting the ph (ring) and pp (ladder) diagrams via a third channel that we here call "crossed-ring" whose presence allows for full fermionic antisymmetry. Additionally, coupled cluster incorporates what we call "mosaic" terms which can be absorbed into defining a new effective one-body Hamiltonian. The inclusion of these mosaic terms seems to be quite important. The pp-RPA an d qp-RPA equations are textbook material in nuclear structure physics but are largely unknown in quantum chemistry, where particle number fluctuations and Bogoliubov determinants are rarely used. We believe that the ideas and connections discussed in this paper may help design improved ways of incorporating RPA correlation into density functionals based on a CC perspective

Using National Measures of Patients' Perceptions of Health Care to Design and Debrief Clinical Simulations

This article describes an innovative approach to using national measures of patients' perspectives of quality health care. Nurses from a regional simulation consortium designed and executed a simulation using the Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey to prepare nurses to improve care and, in turn, enhance patients' perceptions of care. The consortium is currently revising the reporting mechanism to collect data about specific learning objectives based on national quality indicator benchmarks, specifically HCAHPS. This revision reflects the changing needs of health care to include quality metrics in simulation

Nonnegative subtheories and quasiprobability representations of qubits

Negativity in a quasiprobability representation is typically interpreted as an indication of nonclassical behavior. However, this does not preclude states that are non-negative from exhibiting phenomena typically associated with quantum mechanics - the single qubit stabilizer states have non-negative Wigner functions and yet play a fundamental role in many quantum information tasks. We seek to determine what other sets of quantum states and measurements for a qubit can be non-negative in a quasiprobability representation, and to identify nontrivial unitary groups that permute the states in such a set. These sets of states and measurements are analogous to the single qubit stabilizer states. We show that no quasiprobability representation of a qubit can be non-negative for more than four bases and that the non-negative bases in any quasiprobability representation must satisfy certain symmetry constraints. We provide an exhaustive list of the sets of single qubit bases that are non-negative in some quasiprobability representation and are also permuted by a nontrivial unitary group. This list includes two families of three bases that both include the single qubit stabilizer states as a special case and a family of four bases whose symmetry group is the Pauli group. For higher dimensions, we prove that there can be no more than 2^{d^2} states in non-negative bases of a d-dimensional Hilbert space in any quasiprobability representation. Furthermore, these bases must satisfy certain symmetry constraints, corresponding to requiring the bases to be sufficiently complementary to each other.Comment: 17 pages, 8 figures, comments very welcome; v2 published version. Note that the statement and proof of Theorem III.2 in the published version are incorrect (an erratum has been submitted), and this arXiv version (v2) presents the corrected theorem and proof. The conclusions of the paper are unaffected by this correctio

Fractionation effects in phase equilibria of polydisperse hard sphere colloids

The equilibrium phase behaviour of hard spheres with size polydispersity is studied theoretically. We solve numerically the exact phase equilibrium equations that result from accurate free energy expressions for the fluid and solid phases, while accounting fully for size fractionation between coexisting phases. Fluids up to the largest polydispersities that we can study (around 14%) can phase separate by splitting off a solid with a much narrower size distribution. This shows that experimentally observed terminal polydispersities above which phase separation no longer occurs must be due to non-equilibrium effects. We find no evidence of re-entrant melting; instead, sufficiently compressed solids phase separate into two or more solid phases. Under appropriate conditions, coexistence of multiple solids with a fluid phase is also predicted. The solids have smaller polydispersities than the parent phase as expected, while the reverse is true for the fluid phase, which contains predominantly smaller particles but also residual amounts of the larger ones. The properties of the coexisting phases are studied in detail; mean diameter, polydispersity and volume fraction of the phases all reveal marked fractionation. We also propose a method for constructing quantities that optimally distinguish between the coexisting phases, using Principal Component Analysis in the space of density distributions. We conclude by comparing our predictions to perturbative theories for near-monodisperse systems and to Monte Carlo simulations at imposed chemical potential distribution, and find excellent agreement.Comment: 21 pages, 23 figures, 2 table