Manipulation of a Bose-Einstein condensate by a time-averaged orbiting potential using phase jumps of the rotating field

We report on the manipulation of the center-of-mass motion (`sloshing') of a Bose Einstein condensate in a time-averaged orbiting potential (TOP) trap. We start with a condensate at rest in the center of a static trapping potential. When suddenly replacing the static trap with a TOP trap centered about the same position, the condensate starts to slosh with an amplitude much larger than the TOP micromotion. We show, both theoretically and experimentally, that the direction of sloshing is related to the initial phase of the rotating magnetic field of the TOP. We show further that the sloshing can be quenched by applying a carefully timed and sized jump in the phase of the rotating field.Comment: 11 pages, 9 figure

Efficacy of perampanel in a rat model of hypoxic neonatal serizures

Thesis (M.A.)--Boston UniversityNeonatal seizures often lead to the later development of epilepsy and other cognitive disabilities, which may in part be due to calcium (Ca2+)-permeable AMPA receptor (CP-AMPAR)-mediated increases in synaptic plasticity and neuronal excitability. AMPAR subunit trafficking and the mTORC1 pathway are thought to be regulated by CP-AMPAR activity, and both have been implicated in the epileptogenic changes that follow neonatal seizures. The most common cause of neonatal seizures is hypoxic-ischemic encephalopathy. Using an established rat model of neonatal hypoxia- induced seizures, we demonstrate efficacy of the novel AMPAR-antagonist, perampanel, in suppressing seizures. We also attempt to demonstrate the efficacy of perampanel in reversing seizure-induced post-translational changes to GluR1 and two downstream targets of mTORC1, p70S6 kinase and ribosomal protein S6. However, due to limited time and insufficient sample numbers (n) we were unable to show any significant effect of perampanel on these protein targets. We could not replicate the seizure-induced increases in GluR1 subunit (Ser831/845), p70S6 kinase, and S6 phosphorylation that have previously been shown. We were also unable to replicate the efficacy of a different AMPAR antagonist, NBQX, in reversing these seizure-induced increases. These two facts, when taken together with the low n, suggest that our lack of results are likely do to insufficient sample number, and do not necessarily indicate a lack of efficacy for perampanel. Considering perampanel’s favorable anticonvulsant effect in our model, and the previously demonstrated success of other AMPARs as antiepileptogenics, we are hopeful that a further and more in depth study of perampanel will yield more favorable results

Effects of reaction control system jet simulation on the stability and control characteristics of a 0.015-scale space shuttle orbiter model in the Ames Research Center 3.5-foot hypersonic wind tunnel

An experimental investigation was performed in the Ames Research Center 3.5-Foot Hypersonic Wind Tunnel to obtain detailed effects which interactions between the RCS jet flow field and the local orbiter flow field have on orbiter hypersonic stability and control characteristics. Six-component force data were obtained through an angle-of-attack range of 15 to 35 deg with 0 deg angle of sideslip. The test was conducted with yaw, pitch and roll jet simulation at a free-stream Mach number of 10.3. These data simulate two SSV reentry flight conditions at Mach numbers of 28.3 and 10.3. Fuselage base pressures and pressures on the nonmetric RCS pods were obtained in addition to the basic force measurements. Model 42-0 was used for these tests

Results of tests of a 0.010- and 0.015-scale models of space shuttle orbiter configurations 3 and 3A in the Ames Research Center 3.5 foot hypersonic wind tunnel (OA23)

Longitudinal and lateral-directional stability and control characteristics were evaluated at Mach numbers of 5.3, 7.3 and 10.3 at angles of attack up to 50 degrees with Beta = 0 degrees and, for a few cases, Beta = 5 degrees. Component force data, fuselage base pressures and shadowgraph patterns were recorded

Results of an aerodynamic force and moment investigation of an 0.015-scale configuration 3 space shuttle orbiter in the NASA/ARC 3.5-foot hypersonic wind tunnel (OA58)

The primary objective of the test was to obtain stability and control data for the basic configuration and an alternate configuration for the Space Shuttle Orbiter. Pitch runs were made with 0 deg of sideslip at Mach numbers of 5.3, 7.3 and 10.3. Six-component force data and fuselage base pressures were recorded for each run. Shadowgraph pictures were taken at selected points. Model 420 was used for the tests

Wind-Tunnel Tests of a 0.16-Scale Model of the Douglas MX-656 Airplane at High Subsonic Speeds

Wind tunnel tests of the 0.16-scale Douglas MX-656 model were made at low and high subsonic Mach numbers to investigate the static longitudinal- and lateral stability characteristics. The tests shows that undesirable changes in longitudinal stability at the stall were apparently caused by an altered downwash pattern at the tail. The jettisonable nose fins were highly destabilizing. Compressibility effects for the test Mach numbers were not detrimental to the longitudinal- or lateral-stability characteristics

Reconfiguration on sparse graphs

A vertex-subset graph problem Q defines which subsets of the vertices of an input graph are feasible solutions. A reconfiguration variant of a vertex-subset problem asks, given two feasible solutions S and T of size k, whether it is possible to transform S into T by a sequence of vertex additions and deletions such that each intermediate set is also a feasible solution of size bounded by k. We study reconfiguration variants of two classical vertex-subset problems, namely Independent Set and Dominating Set. We denote the former by ISR and the latter by DSR. Both ISR and DSR are PSPACE-complete on graphs of bounded bandwidth and W[1]-hard parameterized by k on general graphs. We show that ISR is fixed-parameter tractable parameterized by k when the input graph is of bounded degeneracy or nowhere-dense. As a corollary, we answer positively an open question concerning the parameterized complexity of the problem on graphs of bounded treewidth. Moreover, our techniques generalize recent results showing that ISR is fixed-parameter tractable on planar graphs and graphs of bounded degree. For DSR, we show the problem fixed-parameter tractable parameterized by k when the input graph does not contain large bicliques, a class of graphs which includes graphs of bounded degeneracy and nowhere-dense graphs