Solar Stereoscopy with STEREO/EUVI A and B spacecraft from small (6 deg) to large (170 deg) spacecraft separation angles

We performed for the first time stereoscopic triangulation of coronal loops in active regions over the entire range of spacecraft separation angles ($\alpha_{sep}\approx 6^\circ, 43^\circ, 89^\circ, 127^\circ$, and $170^\circ$). The accuracy of stereoscopic correlation depends mostly on the viewing angle with respect to the solar surface for each spacecraft, which affects the stereoscopic correspondence identification of loops in image pairs. From a simple theoretical model we predict an optimum range of $\alpha_{sep} \approx 22^\circ-125^\circ$, which is also experimentally confirmed. The best accuracy is generally obtained when an active region passes the central meridian (viewed from Earth), which yields a symmetric view for both STEREO spacecraft and causes minimum horizontal foreshortening. For the extended angular range of $\alpha_{sep}\approx 6^\circ-127^{\circ}$ we find a mean 3D misalignment angle of $\mu_{PF} \approx 21^\circ-39^\circ$ of stereoscopically triangulated loops with magnetic potential field models, and $\mu_{FFF} \approx 15^\circ-21^\circ$ for a force-free field model, which is partly caused by stereoscopic uncertainties $\mu_{SE} \approx 9^\circ$. We predict optimum conditions for solar stereoscopy during the time intervals of 2012--2014, 2016--2017, and 2021--2023.Comment: Solar Physics, (in press), 22 pages, 9 figure

Intraoperative Radiotherapie (IORT) mit Elektronen nach brusterhaltender Operation beim Mammacarcinom

In der vorliegenden Studie wurden die Ergebnisse von 47 Mammacarcinom-Patientinnen analysiert, die zwischen 01/2002 und 10/2005 in der Klinik für Strahlentherapie – Radioonkologie – des Universitätsklinikums Münster im Rahmen der adjuvanten Radiotherapie nach Brusterhalt eine Dosisaufsättigung des Tumorbettes (Boost) durch eine Intraoperative Radiotherapie (IORT) erhalten haben. Die Technik der IORT zeigte sich hierbei als praktisch gut und einfach durchführbar. Normalgewebe und benachbarte Organe konnten geschont werden, gleichzeitig erlaubt die IORT eine optimale Erfassung des Tumorbettes durch direkte Visualisierung. Nach medianer Nachbeobachtungszeit von 30 Monaten sind höhergradige Akut- oder Spätkomplikationen sowie Lokalrezidive nicht aufgetreten. Die kosmetischen Ergebnisse sind überwiegend sehr gut oder gut

The State of Self-Organized Criticality of the Sun During the Last Three Solar Cycles. II. Theoretical Model

The observed powerlaw distributions of solar flare parameters can be interpreted in terms of a nonlinear dissipative system in the state of self-organized criticality (SOC). We present a universal analytical model of a SOC process that is governed by three conditions: (i) a multiplicative or exponential growth phase, (ii) a randomly interrupted termination of the growth phase, and (iii) a linear decay phase. This basic concept approximately reproduces the observed frequency distributions. We generalize it to a randomized exponential-growth model, which includes also a (log-normal) distribution of threshold energies before the instability starts, as well as randomized decay times, which can reproduce both the observed occurrence frequency distributions and the scatter of correlated parametyers more realistically. With this analytical model we can efficiently perform Monte-Carlo simulations of frequency distributions and parameter correlations of SOC processes, which are simpler and faster than the iterative simulations of cellular automaton models. Solar cycle modulations of the powerlaw slopes of flare frequency distributions can be used to diagnose the thresholds and growth rates of magnetic instabilities responsible for solar flares.Comment: Part II of Paper I: The State of Self-Organized Criticality of the Sun During the Last Three Solar Cycles. I. Observation

A Nonlinear Force-Free Magnetic Field Approximation Suitable for Fast Forward-Fitting to Coronal Loops. I. Theory

We derive an analytical approximation of nonlinear force-free magnetic field solutions (NLFFF) that can efficiently be used for fast forward-fitting to solar magnetic data, constrained either by observed line-of-sight magnetograms and stereoscopically triangulated coronal loops, or by 3D vector-magnetograph data. The derived NLFFF solutions provide the magnetic field components $B_x({\bf x})$, $B_y({\bf x})$, $B_z({\bf x})$, the force-free parameter $\alpha({\bf x})$, the electric current density ${\bf j}({\bf x})$, and are accurate to second-order (of the nonlinear force-free $\alpha$-parameter). The explicit expressions of a force-free field can easily be applied to modeling or forward-fitting of many coronal phenomena.Comment: Solar Physics (in press), 26 pages, 11 figure

A Nonlinear Force-Free Magnetic Field Approximation Suitable for Fast Forward-Fitting to Coronal Loops. II. Numeric Code and Tests

Based on a second-order approximation of nonlinear force-free magnetic field solutions in terms of uniformly twisted field lines derived in Paper I, we develop here a numeric code that is capable to forward-fit such analytical solutions to arbitrary magnetogram (or vector magnetograph) data combined with (stereoscopically triangulated) coronal loop 3D coordinates. We test the code here by forward-fitting to six potential field and six nonpotential field cases simulated with our analytical model, as well as by forward-fitting to an exactly force-free solution of the Low and Lou (1990) model. The forward-fitting tests demonstrate: (i) a satisfactory convergence behavior (with typical misalignment angles of $\mu \approx 1^\circ-10^\circ$), (ii) relatively fast computation times (from seconds to a few minutes), and (iii) the high fidelity of retrieved force-free $\alpha$-parameters ($\alpha_{\rm fit}/\alpha_{\rm model} \approx 0.9-1.0$ for simulations and $\alpha_{\rm fit}/\alpha_{\rm model} \approx 0.7\pm0.3$ for the Low and Lou model). The salient feature of this numeric code is the relatively fast computation of a quasi-forcefree magnetic field, which closely matches the geometry of coronal loops in active regions, and complements the existing {\sl nonlinear force-free field (NLFFF)} codes based on photospheric magnetograms without coronal constraints.Comment: Solar PHysics, (in press), 25 pages, 11 figure

Narrow Stimulated Resonance Raman Scattering and WGM Lasing in Small Conjugated Polymer Particles for Live Cell Tagging and Tracking

Conjugated polymer particles are brightly fluorescing and stable materials for live cell imaging. Combination of conjugated polymers with a whispering gallery mode (WGM) resonator allows laser emission from microscale particles. Once internalized by cells, the mode pattern of the laser emission can be used for tagging and tracking, as each laser spectrum represents a bar code to identify individual cells. However, currently these particle systems are limited by their large size, which might interfere with cellular functions. Here, stimulated resonance Raman scattering (SRRS) in small conjugated polymer microparticles is presented as a new method for generating narrow emission as an alternative to WGM-based laser emission. This opens up spectral range for multiplexing optical readout and multicolor imaging of live cells. The synthesis of monodisperse micrometer-sized poly(fluorene-co-divinylbenzene) particles is discussed and their WGM and SRRS emission are characterized. Finally, how these particles and their emission can be employed in live cell imaging and tagging is showcased. © 2020 The Authors. Advanced Optical Materials published by Wiley-VCH Gmb

The State of Self-Organized Criticality of the Sun During the Last 3 Solar Cycles. I. Observations

We analyze the occurrence frequency distributions of peak fluxes $P$, total fluxes $E$, and durations $T$ of solar flares over the last three solar cycles (during 1980--2010) from hard X-ray data of HXRBS/SMM, BATSE/CGRO, and RHESSI. From the synthesized data we find powerlaw slopes with mean values of $\alpha_P=1.72\pm0.08$ for the peak flux, $\alpha_E=1.60\pm0.14$ for the total flux, and $\alpha_T=1.98\pm0.35$ for flare durations. We find a systematic anti-correlation of the powerlaw slope of peak fluxes as a function of the solar cycle, varying with an approximate sinusoidal variation $\alpha_P(t)=\alpha_0+\Delta \alpha \cos{[2\pi (t-t_0)/T_{cycle}]}$, with a mean of $\alpha_0=1.73$, a variation of $\Delta \alpha =0.14$, a solar cycle period $T_{cycle}=12.6$ yrs, and a cycle minimum time $t_0=1984.1$. The powerlaw slope is flattest during the maximum of a solar cycle, which indicates a higher magnetic complexity of the solar corona that leads to an overproportional rate of powerful flares.Comment: subm. to Solar Physic

Macroscopic Strings and "Quirks" at Colliders

We consider extensions of the standard model containing additional heavy particles ("quirks") charged under a new unbroken non-abelian gauge group as well as the standard model. We assume that the quirk mass m is in the phenomenologically interesting range 100 GeV--TeV, and that the new gauge group gets strong at a scale Lambda < m. In this case breaking of strings is exponentially suppressed, and quirk production results in strings that are long compared to 1/Lambda. The existence of these long stable strings leads to highly exotic events at colliders. For 100 eV < Lambda < keV the strings are macroscopic, giving rise to events with two separated quirk tracks with measurable curvature toward each other due to the string interaction. For keV < Lambda < MeV the typical strings are mesoscopic: too small to resolve in the detector, but large compared to atomic scales. In this case, the bound state appears as a single particle, but its mass is the invariant mass of a quirk pair, which has an event-by-event distribution. For MeV < Lambda < m the strings are microscopic, and the quirks annihilate promptly within the detector. For colored quirks, this can lead to hadronic fireball events with 10^3 hadrons with energy of order GeV emitted in conjunction with hard decay products from the final annihilation.Comment: Added discussion of photon-jet decay, fixed minor typo

Conformal Technicolor

We point out that the flavor problem in theories with dynamical electroweak symmetry breaking can be effectively decoupled if the physics above the TeV scale is strongly conformal, and the electroweak order parameter has a scaling dimension d = 1 + epsilon with epsilon \simeq 1/few. There are many restrictions on small values of epsilon: for epsilon << 1, electroweak symmetry breaking requires a fine-tuning similar to that of the standard model; large-N conformal field theories (including those obtained from the AdS/CFT correspondence) require fine-tuning for d < 2; `walking technicolor' theories cannot have d < 2, according to gap equation analyses. However, strong small-N conformal field theories with epsilon \simeq 1/few avoid all these constraints, and can give rise to natural dynamical electroweak symmetry breaking with a top quark flavor scale of order 10^{1/epsilon} TeV, large enough to decouple flavor. Small-N theories also have an acceptably small Peskin-Takeuchi S parameter. This class of theories provides a new direction for dynamical electroweak symmetry breaking without problems from flavor or electroweak precision tests. A possible signal for these theories is a prominent scalar resonance below the TeV scale with couplings similar to a heavy standard model Higgs.Comment: 26 pages + References. Slight wording changes. Version appearing in JHE