Invariance of the Cuntz splice

We show that the Cuntz splice induces stably isomorphic graph $C^*$-algebras.Comment: Our arguments to prove invariance of the Cuntz splice for unital graph C*-algebras in arXiv:1505.06773 applied with only minor changes in the general case. Since most of the results of that preprint have since been superseded by other forthcoming work, we do not intend to publish it, whereas this work is intended for publication. arXiv admin note: substantial text overlap with arXiv:1505.0677

The Circular Velocity Curve of the Milky Way from 55 to 2525 kpc

We measure the circular velocity curve $v_{\rm c}(R)$ of the Milky Way with the highest precision to date across Galactocentric distances of $5\leq R \leq 25$ kpc. Our analysis draws on the $6$-dimensional phase-space coordinates of $\gtrsim 23,000$ luminous red-giant stars, for which we previously determined precise parallaxes using a data-driven model that combines spectral data from APOGEE with photometric information from WISE, 2MASS, and Gaia. We derive the circular velocity curve with the Jeans equation assuming an axisymmetric gravitational potential. At the location of the Sun we determine the circular velocity with its formal uncertainty to be $v_{\rm c}(R_{\odot}) = (229.0\pm0.2)\rm\,km\,s^{-1}$ with systematic uncertainties at the $\sim 2-5\%$ level. We find that the velocity curve is gently but significantly declining at $(-1.7\pm0.1)\rm\,km\,s^{-1}\,kpc^{-1}$, with a systematic uncertainty of $0.46\rm\,km\,s^{-1}\,kpc^{-1}$, beyond the inner $5$ kpc. We exclude the inner $5$ kpc from our analysis due to the presence of the Galactic bar, which strongly influences the kinematic structure and requires modeling in a non-axisymmetric potential. Combining our results with external measurements of the mass distribution for the baryonic components of the Milky Way from other studies, we estimate the Galaxy's dark halo mass within the virial radius to be $M_{\rm vir} = (7.25\pm0.26)\cdot 10^{11}M_{\odot}$ and a local dark matter density of $\rho_{\rm dm}(R_{\odot}) = 0.30\pm0.03\,\rm GeV\,cm^{-3}$.Comment: Accepted for publication in ApJ. All data can be downloaded here: https://doi.org/10.5281/zenodo.146805

Sensory pathways of muscle phenotypic plasticity: Calcium signalling through CaMKII

Haan, A. de [Promotor]Flueck, M. [Promotor]Jaspers, R.T. [Copromotor

Amplified graph C*-algebras

We provide a complete invariant for graph C*-algebras which are amplified in the sense that whenever there is an edge between two vertices, there are infinitely many. The invariant used is the standard primitive ideal space adorned with a map into {-1,0,1,2,...}, and we prove that the classification result is strong in the sense that isomorphisms at the level of the invariant always lift. We extend the classification result to cover more graphs, and give a range result for the invariant (in the vein of Effros-Handelman-Shen) which is further used to prove that extensions of graph C*-algebras associated to amplified graphs are again graph C*-algebras of amplified graphs.Comment: 15 pages, 1 figur

Spectrophotometric parallaxes with linear models: Accurate distances for luminous red-giant stars

With contemporary infrared spectroscopic surveys like APOGEE, red-giant stars can be observed to distances and extinctions at which Gaia parallaxes are not highly informative. Yet the combination of effective temperature, surface gravity, composition, and age - all accessible through spectroscopy - determines a giant's luminosity. Therefore spectroscopy plus photometry should enable precise spectrophotometric distance estimates. Here we use the APOGEE-Gaia-2MASS-WISE overlap to train a data-driven model to predict parallaxes for red-giant branch stars with $0<\log g\leq2.2$ (more luminous than the red clump). We employ (the exponentiation of) a linear function of APOGEE spectral pixel intensities and multi-band photometry to predict parallax spectrophotometrically. The model training involves no logarithms or inverses of the Gaia parallaxes, and needs no cut on the Gaia parallax signal-to-noise ratio. It includes an L1 regularization to zero out the contributions of uninformative pixels. The training is performed with leave-out subsamples such that no star's astrometry is used even indirectly in its spectrophotometric parallax estimate. The model implicitly performs a reddening and extinction correction in its parallax prediction, without any explicit dust model. We assign to each star in the sample a new spectrophotometric parallax estimate; these parallaxes have uncertainties of a few to 15 percent, depending on data quality, which is more precise than the Gaia parallax for the vast majority of targets, and certainly any stars more than a few kpc distance. We obtain 10-percent distance estimates out to heliocentric distances of $20\,$kpc, and make global maps of the Milky Way's disk.Comment: Submitted to ApJ, comments are welcome. All data can be downloaded here: https://doi.org/10.5281/zenodo.146805

Analytical and Experimental Evaluation of Aerodynamic Thrust Vectoring on an Aerospike Nozzle

Results from numerical and cold-flow experimental investigations of aerodynamic thrust vectoring on a small-scale aerospike thruster are presented. Thrust vectoring was created by the injection of a secondary fluid into the primary flow field normal to the nozzle axis. The experimental aerospike nozzle was truncated at 57% of its full theoretical length. Data derived from cold-flow thrust vectoring tests with carbon dioxide as the working fluid are presented. Injection points near the end of the truncated spike produced the highest force amplification factors. Explanations are given for this phenomenon. For secondary injection near the end of the aerospike, side force amplification factors up to approximately 1.4 and side force specific impulses up to approximately 55 s with main flow specific impulses clustering around 38 s were demonstrated. These forces crisply reproduce input pulses with a high degree of fidelity. The side force levels are approximately 2.7% of the total thrust level at maximum effectiveness. Higher side forces on the order of 4.7% of axial thrust were also achieved at reduced efficiency. The side force amplification factors were independent of operating nozzle pressure ratio for the range of chamber pressures used in this test series