Multifrequency Polarimetry of the Nrao 140 Jet: Possible Detection of a Helical Magnetic Field and Constraints on its Pitch Angle

We present results from multifrequency polarimetry of NRAO 140 using the Very Long Baseline Array. These observations allow us to reveal the distributions of both the polarization position angle and the Faraday rotation measure (RM). These distributions are powerful tools to discern the projected and line-of-sight components of the magnetic field, respectively. We find a systematic gradient in the RM distribution, with its sign being opposite at either side of the jet with respect to the jet axis. The sign of the RM changes only with the direction of the magnetic field component along the line of sight, so this can be explained by the existence of helical magnetic components associated with the jet itself. We derive two constraints for the pitch angle of the helical magnetic field from the distributions of the RM and the projected magnetic field; the RM distribution indicates that the helical fields are tightly wound, while that of the projected magnetic field suggests they are loosely wound around the jet axis. This inconsistency may be explained if the Faraday rotator is not cospatial with theemitting region. Our results may point toward a physical picture in which an ultra-relativistic jet (spine) with a loosely wound helical magnetic field is surrounded by a sub-relativistic wind layer (sheath) with a tightly wound helical magnetic field.Comment: 12 pages, 4 figures, ApJ, in pres

Interpreting the time variable RM observed in the core region of the TeV blazar Mrk 421

In this work we interpret and discuss the time variable rotation measure (RM) found, for the first time over a 1-yr period, in the core region of a blazar. These results are based on a one-year, multi-frequency (15, 24, and 43 GHz) Very Long Baseline Array (VLBA) monitoring of the TeV blazar Markarian 421 (Mrk 421). We investigate the Faraday screen properties and its location with respect to the jet emitting region. Given that the 43 GHz radio core flux density and the RM time evolution suggest a similar trend, we explore the possible connection between the RM and the accretion rate. Among the various scenarios that we explore, the jet sheath is the most promising candidate for being the main source of Faraday rotation. During the one-year observing period the RM trend shows two sign reversals, which may be qualitatively interpreted within the context of the magnetic tower models. We invoke the presence of two nested helical magnetic fields in the relativistic jet with opposite helicities, whose relative contribution produce the observed RM values. The inner helical field has the poloidal component ($B_{\rm p}$) oriented in the observer's direction and produces a positive RM, while the outer helical field, with $B_{\rm p}$ in the opposite direction, produces a negative RM. We assume that the external helical field dominates the contribution to the observed RM, while the internal helical field dominates when a jet perturbation arises during the second observing epoch. Being the intrinsic polarization angle parallel to the jet axis, a pitch angle of the helical magnetic field $\phi\gtrsim 70^\circ$ is required. Additional scenarios are also considered to explain the observed RM sign reversals.Comment: 6 pages, 2 figures. Published on MNRA

Data report: Summary of revised alteration phases for PACMANUS hydrothermal field - X-ray diffraction analysis of altered felsic volcanic rocks from Holes 1188A, 1188F, 1189A and 1189B

Postcruise X-ray diffraction (XRD) data for 95 whole-rock samples from Holes 1188A, 1188F, 1189A, and 1189B are presented. The samples represent alteration types recovered during Leg 193. The data set is incorporated into the shipboard XRD data set. Based on the newly obtained XRD data, distribution of alteration phases were redrawn for Ocean Drilling Program Sites 1188 and 1189

Separability of Rotational Effects on a Gravitational Lens

We derive the deflection angle up to $O(m^2a)$ due to a Kerr gravitational lens with mass $m$ and specific angular momentum $a$. It is known that at the linear order in $m$ and $a$ the Kerr lens is observationally equivalent to the Schwarzschild one because of the invariance under the global translation of the center of the lens mass. We show, however, nonlinear couplings break the degeneracy so that the rotational effect becomes in principle separable for multiple images of a single source. Furthermore, it is distinguishable also for each image of an extended source and/or a point source in orbital motion. In practice, the correction at $O(m^2a)$ becomes $O(10^{-10})$ for the supermassive black hole in our galactic center. Hence, these nonlinear gravitational lensing effects are too small to detect by near-future observations.Comment: 12 pages (RevTeX); accepted for publication in Phys. Rev.

On the jets, kinks, and spheromaks formed by a planar magnetized coaxial gun

Measurements of the various plasma configurations produced by a planar magnetized coaxial gun provide insight into the magnetic topology evolution resulting from magnetic helicity injection. Important features of the experiments are a very simple coaxial gun design so that all observed geometrical complexity is due to the intrinsic physical dynamics rather than the source shape and use of a fast multiple-frame digital camera which provides direct imaging of topologically complex shapes and dynamics. Three key experimental findings were obtained: (1) formation of an axial collimated jet [Hsu and Bellan, Mon. Not. R. Astron. Soc. 334, 257 (2002)] that is consistent with a magnetohydrodynamic description of astrophysical jets, (2) identification of the kink instability when this jet satisfies the Kruskal-Shafranov limit, and (3) the nonlinear properties of the kink instability providing a conversion of toroidal to poloidal flux as required for spheromak formation by a coaxial magnetized source [Hsu and Bellan, Phys. Rev. Lett. 90, 215002 (2003)]. A new interpretation is proposed for how the n=1 central column instability provides flux amplification during spheromak formation and sustainment, and it is shown that jet collimation can occur within one rotation of the background poloidal field.Comment: Physics of Plasmas (accepted

The wave front set of oscillatory integrals with inhomogeneous phase function

A generalized notion of oscillatory integrals that allows for inhomogeneous phase functions of arbitrary positive order is introduced. The wave front set of the resulting distributions is characterized in a way that generalizes the well-known result for phase functions that are homogeneous of order one.Comment: 12 pages, published versio

ALMA Science Verification Data: Millimeter Continuum Polarimetry of the Bright Radio Quasar 3C 286

We present full-polarization observations of the compact, steep-spectrum radio quasar 3C~286 made with the ALMA at 1.3~mm. These are the first full-polarization ALMA observations, which were obtained in the framework of Science Verification. A bright core and a south-west component are detected in the total intensity image, similar to previous centimeter images. Polarized emission is also detected toward both components. The fractional polarization of the core is about 17\%, this is higher than the fractional polarization at centimeter wavelengths, suggesting that the magnetic field is even more ordered in the millimeter radio core than it is further downstream in the jet. The observed polarization position angle (or EVPA) in the core is $\sim$\,$39^{\circ}$, which confirms the trend that the EVPA slowly increases from centimeter to millimeter wavelengths. With the aid of multi-frequency VLBI observations, we argue that this EVPA change is associated with the frequency-dependent core position. We also report a serendipitous detection of a sub-mJy source in the field of view, which is likely to be a submillimeter galaxy.Comment: 10 pages, 9 figures, Accepted for publication in the Ap

Promotive effects of hyperthermia on the сytostatic activity to ehrlich ascites tumor cells by diverse delta-alkyllactones

To evaluate promotive effects of hyperthermia on antitumor activity of new delta-alkyllactones (DALs) of low molecular weight (184–254 Da), chemically synthesized, which are different from natural macrocyclic lactones of high molecular weight (348–439 Da), such as camptothecin and sultriecin. Methods: A suspension of Ehrlich ascites tumor (EAT) cells was mixed with a DAL in a glass tube, heated at 37 or 42 °C for 30 min in a water bath, and cultured at 37 °C for 20 or 72 h. Cell viability was measured by the mitochondrial dehydrogenase- based WST-1 assay. DALs incorporated into EAT cells was extracted and measured by gas-liquid chromatography. Results: The reduction of cell viability by DALs was markedly enhanced upon the treatment at 42 °C compared to that at 37 oC. At 37 oC, delta-hexadecalactone (DH16 : 0) and delta-tetradecalactone (DTe14 : 0) displayed cytostatic activity (at 100 µM survival level: 20.7%, 66.1%; at 50 µM — 41.2%, 82.4%, respectively). Their activity was more marked at 42 °C (at 100 µM 10.6%, 27.6%; at 50 µM 30.6, 37.5 %, ibid). The other DALs, delta-undecalactone (DU11 : 0), delta-dodecalactone (DD12 : 0), and delta-tridecanolactone (DTr13 : 0) were almost ineffective. Evaluation of survival rate in the cells treated for 30 min by DALs with the next culturing of EAT cells for 72 h resulted in the enhanced carcinostatic activity of DH16:0 and DTe14:0 even at concentrations as low as 25 µM at either 37 °C (18.5%, 78.5%, ibid) or 42 °C (5.0%, 42.0%, ibid), but the others exhibited slight activity or none. DH16 : 0 was effective at either 37 °C (36.0%) or 42 °C (23.0%) even at a lower dose of 10 µM. At the same time only the most cytostatic DH16 : 0 was incorporated into EAT cells and the rate of incorporation was more at 42 °C than at 37 °C. Conclusion: Delta-hexadecanolactone (DH16 : 0) exhibited the most cytostatic effect that was significantly enhanced by hyperthermia. It allows to consider it as a potent antitumor agent, especially in combination with hyperthermia.Цель: оценить промоторный эффект гипертермии на противоопухолевую активность новых низкомолекулярных (184–254 Да) дельта-алкиллактонов (DALs), химически синтезированных из разных макроциклических высокомолекулярных (348–439Да) лактонов естественного происхождения, таких как камптотецин и салтриецин. Методы: суспензию клеток асцитной опухоли Эрлиха (EAT) смешивали с DAL в стеклянной пробирке, нагревали до 37 °C или 42 °C в течение 30 мин на водяной бане и далее культивировали при 37 °C в течение 20 или 72 ч. Оценку жизнеспособности клеток проводили с помощью WST-1 анализа, основанного на определении митохондриальной дегидрогеназы. Инкорпорированные в EAT-клетки DALs экстрагировали, их уровень измеряли с помощью газо-жидкостной хроматографии. Результаты: DALs значительно снижали жизнеспособность клеток после предварительной обработки при 42 °C по сравнению с 37 °C. При 37 °C были эффективными дельта-гексадекалактон (DH16 : 0) и дельта-тетрадекалактон (DTe14 : 0) (при 100 μM уровень выживаемости: 20,7; 66,1%; при 50 μM — 41,2; 82,4% соответственно). Этот эффект был более выраженным при 42 °C (при 100 μM 10,6; 27,6%; при 50μM 30,6; 37,5% соответственно). Другие DALs, а именно дельта-ундекалактон (DU11 : 0), дельта-додекалактон (DD12 : 0) и дельта-тридекалактон (DTr13 : 0) были практически не эффективны. Оценка уровня выживаемости EAT-клеток, 30 мин обработанных DALs с последующим культивированием в течение 72 ч, показала повышенную канцеростатичсекую активность DH16 : 0 и DTe14 :0 даже при 25 μM концентрации, как при 37 °C (18,5; 78,5% соответсвенно), так и при 42 °C (5,0; 42,0% соответственно). Для других DALs данный эффект был незначительный либо отсутствовал. DH16 : 0 оставался эффективным как при 37 °C (36,0%), так и при 42 °C (23,0%) в 10 μM концентрации. В то же время только наиболее эффективный DAL — DH16 : 0 инкорпорировался в клетки EAT, и уровень инкорпорирования был выше при 42 °C, чем при 37 °C. Выводы: дельта-гексадеканолактон (DH16 : 0) показал наибольшую цитостатическую активность, которая значительно усиливалась в комбинации с гипертермией. Этот DAL можно рассматривать как потенциальный цитостатик, действие которого усиливается при гипертермии

INEF12Basketball Dataset and the Group Behavior Recognition Issue

Proceedings of: 9th Conference on Practical Applications of Agents and Multi-Agent Systems. Workshop on User-Centric Technologies and Applications (CONTEXTS 2012), Salamanca, March 28-30, 2012Activity recognition is one of the most prolific fields of research. For this reason, there are new fields of research that expand the possibilities of the activity recognition: Group behavior recognition. This field does not limit the number of elements in the scene, and there are a lot of new elements that must be analyzed. Each group, like each individual element, has its behavior, but this behavior depends on their elements, and the relationships between these elements. All these new elements cause that group behavior recognition was a new field of research, with some similar elements but it must be studied apart. This way, group behavior recognition is a novel field, in which there are not many researches and there are not many datasets that could be used by researchers. This situation causes the slow advance of the science in this field. This paper tries to show a complete description of the problem domain, with all the possible variants, a formal description and show a novel architecture used to solve this issue. Also describes a specific group behavior recognition dataset, and shows how it could be usedThis work was supported in part by Projects CICYT TIN2011-28620-C02-01, CICYT TEC2011-28626-C02-02, CAMCONTEXTS (S2009/TIC-1485) and DPS2008-07029-C02-02Publicad

Faraday rotation in the MOJAVE blazars: 3C 273 a case study

Radio polarimetric observations of Active Galactic Nuclei can reveal the magnetic field structure in the parsec-scale jets of these sources. We have observed the gamma-ray blazar 3C 273 as part of our multi-frequency survey with the Very Long Baseline Array to study Faraday rotation in a large sample of jets. Our observations re-confirm the transverse rotation measure gradient in 3C 273. For the first time the gradient is seen to cross zero which is further indication for a helical magnetic field and spine-sheath structure in the jet. We believe the difference to previous epochs is due to a different part of the jet being illuminated in our observations.Comment: 6 pages, 3 figures. To appear in the proceedings of "Beamed and Unbeamed Gamma-rays from Galaxies", held in Muonio, Finland, April 11-15, 2011. Journal of Physics: Conference Serie