Operator product expansion of the energy momentum tensor in 2D conformal field theories on manifolds with boundary

Starting from the well-known expression for the trace anomaly we derive the $T\cdot T$ operator product expansion of the energy-momentum tensor in 2D conformal theories defined in the upper halfplane $without$ making use of the additional condition of no energy-momentum flux across the boundary. The OPE turns out to be the same as in the absence of the boundary. For this result it is crucial that the trace anomaly is proportional to the Gau\ss-Bonnet density. Some relations to the $\sigma$ - model approach for open strings are discussed.Comment: 8 pages, Latex, HU Berlin-IEP-93/

Is the physics within the Solar system really understood?

A collection is made of presently unexplained phenomena within our Solar system and in the universe. These phenomena are (i) the Pioneer anomaly, (ii) the flyby anomaly, (iii) the increase of the Astronomical Unit, (iv) the quadrupole and octupole anomaly, and (v) Dark Energy and (vi) Dark Matter. A new data analysis of the complete set of Pioneer data is announced in order to search for systematic effects or to confirm the unexplained acceleration. We also review the mysterious flyby anomaly where the velocities of spacecraft after Earth swing--bys are larger than expected. We emphasize the scientific aspects of this anomaly and propose systematic and continuous observations and studies at the occasion of future flybys. Further anomalies within the Solar system are the increase of the Astronomical Unit and the quadrupole and octupole anomaly. We briefly mention Dark Matter and Dark Energy since in some cases a relation between them and the Solar system anomalies have been speculated.Comment: 22 pages, 3 figures, submitted for the proceedings of the 359th WE-Heraeus Seminar on "Lasers, Clocks, and Drag-Free: Technologies for Future Exploration in Space and Tests of Gravity

Bayesian analysis of magnetic island dynamics

We examine a first order differential equation with respect to time coming up in the description of magnetic islands in magnetically confined plasmas. The free parameters of this equation are obtained by employing Bayesian probability theory. Additionally a typical Bayesian change point is solved in the process of obtaining the data.Comment: 10 pages, 4 figures, submitted to be included in MaxEnt 2002 proceeding

The local dust foregrounds in the microwave sky: I. Thermal emission spectra

Analyses of the cosmic microwave background (CMB) radiation maps made by the Wilkinson Microwave Anisotropy Probe (WMAP) have revealed anomalies not predicted by the standard inflationary cosmology. In particular, the power of the quadrupole moment of the CMB fluctuations is remarkably low, and the quadrupole and octopole moments are aligned mutually and with the geometry of the Solar system. It has been suggested in the literature that microwave sky pollution by an unidentified dust cloud in the vicinity of the Solar system may be the cause for these anomalies. In this paper, we simulate the thermal emission by clouds of spherical homogeneous particles of several materials. Spectral constraints from the WMAP multi-wavelength data and earlier infrared observations on the hypothetical dust cloud are used to determine the dust cloud's physical characteristics. In order for its emissivity to demonstrate a flat, CMB-like wavelength dependence over the WMAP wavelengths (3 through 14 mm), and to be invisible in the infrared light, its particles must be macroscopic. Silicate spheres from several millimetres in size and carbonaceous particles an order of magnitude smaller will suffice. According to our estimates of the abundance of such particles in the Zodiacal cloud and trans-neptunian belt, yielding the optical depths of the order of 1E-7 for each cloud, the Solar-system dust can well contribute 10 microKelvin (within an order of magnitude) in the microwaves. This is not only intriguingly close to the magnitude of the anomalies (about 30 microKelvin), but also alarmingly above the presently believed magnitude of systematic biases of the WMAP results (below 5 microKelvin) and, to an even greater degree, of the future missions with higher sensitivities, e.g. PLANCK.Comment: 33 pages, 9 figures, 1 table. The Astrophysical Journal, 2009, accepte

Decomposition of multicomponent mass spectra using Bayesian probability theory

We present a method for the decomposition of mass spectra of mixture gases using Bayesian probability theory. The method works without any calibration measurement and therefore applies also to the analysis of spectra containing unstable species. For the example of mixtures of three different hydrocarbon gases the algorithm provides concentrations and cracking coefficients of each mixture component as well as their confidence intervals. The amount of information needed to obtain reliable results and its relation to the accuracy of our analysis are discussed

The determination and distribution of precise time

Methods for time determination including atomic clocks and distribution of timing signal

Transient transfection induces different intracellular calcium signaling in CHO K1 versus HEK 293 cells

For the controlled production of recombinant proteinsin mammalian cells by transient transfection, it maybe desirable not only to manipulate, but also todiagnose the expression success early. Here, weapplied laser scanning confocal microscopy to monitortransfection induced intracellular Ca2+responses. We compared Chinese hamster ovary (CHO K1)versus human embryo kidney (HEK) 293 cell lines, whichdiffer largely in their transfectability. An improvedcalcium phosphate transfection method was used for itssimplicity and its demonstrated upscale potential.Cytosolic Ca2+ signaling appeared to inverselyreflect the cellular transfection fate. Virtually allCHO cells exhibited asynchronous, cytosolicCa2+ oscillations, which peaked 4 h afteraddition of the transfecting solution. Yet, most ofthe HEK cells displayed a slow and continuousCa2+ increase over the time of transfection. CHOcells, when exposed to a transfection-enhancingglycerol shock, strongly downregulated their Ca2+response, including its oscillations. When treatedwith thapsigargin, a Ca2+ store depleting drug,the number of successfully transfected CHO cells was significantly reduced. Our result points tointracellular store release as a critical componentfor the transfection fate of CHO cells, and its early detection before product visualizatio