Cluster Turbulence: Simulation Insights

Cluster media are dynamical, not static; observational evidence suggests they are turbulent. High-resolution simulations of the intracluster media (ICMs) and of idealized, similar media help us understand the complex physics and astrophysics involved. We present a brief overview of the physics behind ICM turbulence and outline the processes that control its development. High-resolution, compressible, isothermal MHD simulations are used to illustrate important dynamical properties of turbulence that develops in media with initially very weak magnetic fields. The simulations follow the growth of magnetic fields and reproduce the characteristics of turbulence. These results are also compared with full cluster simulations that have examined the properties of ICM turbulence.Comment: 7 pages, 2 figures. To appear the proceedings of the conference "Non-thermal Phenomena in Colliding Galaxy Clusters" (Nice, 15-18 November, 2010), Memorie della Societa Astronomica Italiana, vol 82, n

Reviews

The following publications have been reviewed by the mentioned authors;Graphics and Design by R. W. Boycott and J. Bolan, reviewed by Richard KimbellThe Practical Woodwork Book: Anthony Hontoir by John Murray, reviewed by David JonesIntroducing Art - A first book on the History and Appreciation of the Visual Arts by Donald Richardson, reviewed by John LancasterSoldering and Brazing by Tubol Cain, reviewed by  W. T. PriceSheet Metal Work by R. E. Wakefield, reviewed by W. T. PriceThe Art of Welding by W. A. Vause, reviewed by W. T. PriceWorld and Image: A Journal of Verbal/Visual Enquiry. First Issues: Vol.1, January-March 1985 by John Dixon Hunt, reviewed by John LancasterTeachers, Computers and the Classroom by I. Reid and J. Rushton, reviewed by Sean NeillDesign Courses in Britain 1986 by The Design Council, reviewed by J. BarlowGender, science and technology: Inservice handbook by Judith Whyte, reviewed by T. Dore

Using coupled micropillar compression and micro-Laue diffraction to investigate deformation mechanisms in a complex metallic alloy Al13Co4

In this investigation, we have used in-situ micro-Laue diffraction combined with micropillar compression of focused ion beam milled Al13Co4 complex metallic alloy to study the evolution of deformation in Al13Co4. Streaking of the Laue spots showed that the onset of plastic flow occured at stresses as low as 0.8 GPa, although macroscopic yield only becomes apparent at 2 GPa. The measured misorientations, obtained from peak splitting, enabled the geometrically necessary dislocation density to be estimated as 1.1 x 1013 m-2

Pediatric high-grade glioma: biologically and clinically in need of new thinking.

High-grade gliomas in children are different from those that arise in adults. Recent collaborative molecular analyses of these rare cancers have revealed previously unappreciated connections among chromatin regulation, developmental signaling, and tumorigenesis. As we begin to unravel the unique developmental origins and distinct biological drivers of this heterogeneous group of tumors, clinical trials need to keep pace. It is important to avoid therapeutic strategies developed purely using data obtained from studies on adult glioblastoma. This approach has resulted in repetitive trials and ineffective treatments being applied to these children, with limited improvement in clinical outcome. The authors of this perspective, comprising biology and clinical expertise in the disease, recently convened to discuss the most effective ways to translate the emerging molecular insights into patient benefit. This article reviews our current understanding of pediatric high-grade glioma and suggests approaches for innovative clinical management

Spectrum of Neutral Helium in Strong Magnetic Fields

We present extensive and accurate calculations for the excited state spectrum of spin-polarized neutral helium in a range of magnetic field strengths up to $10^{12}$ G. Of considerable interest to models of magnetic white dwarf stellar atmospheres, we also present results for the dipole strengths of the low lying transitions among these states. Our methods rely on a systematically saturated basis set approach to solving the Hartree--Fock self-consistent field equations, combined with an ``exact'' stochastic method to estimate the residual basis set truncation error and electron correlation effects. We also discuss the applicability of the adiabatic approximation to strongly magnetized multi-electron atoms.Comment: 19 pages, 7 figures, 10 table

Partial melting of ordinary chondrites: Lost City (H) and St. Severin (LL)

Eucrites and diogenites are examples of asteroidal basalts and orthopyroxenites, respectively. As they are found intermingled in howardites, which are inferred to be regolith breccias, eucrites and diogenites are thought to be genetically related. But the details of this relationship and of their individual origins remain controversial. Work by Jurewicz et al. showed that 1170-1180 C partial melts of the (anhydrous) Murchison (CM) chondrite have major element compositions extremely similar to primitive eucrites, such as Sioux County. However, the MnO contents of these melts were about half that of Sioux County, a problem for the simple partial melting model. In addition, partial melting of Murchison could not produce diogenites, because residual pyroxenes in the Murchison experiments were too Fe- and Ca-rich and were minor phases at all but the lowest temperatures. A parent magma for diogenites needs an expanded low-calcium pyroxene field. In their partial melting study of an L6 chondrite, Kushiro and Mysen found that ordinary chondrites did have an expanded low-Ca pyroxene field over that of CV chondrites (i.e., Allende), probably because ordinary chondrites have lower Mg/Si ratios. This study expands that of both Kushiro and Mysen and Jurewicz et al. to the Lost City (H) and St. Severin (LL) chondrites at temperatures ranging from 1170 to 1325 C, at an fO2 of one log unit below the iron-wuestite buffer (IW-1)

From Blame to Punishment: Disrupting Prefrontal Cortex Activity Reveals Norm Enforcement Mechanisms

The social welfare provided by cooperation depends on the enforcement of social norms. Determining blameworthiness and assigning a deserved punishment are two cognitive cornerstones of norm enforcement. Although prior work has implicated the dorsolateral prefrontal cortex (DLPFC) in norm-based judgments, the relative contribution of this region to blameworthiness and punishment decisions remains poorly understood. Here, we used repetitive transcranial magnetic stimulation (rTMS) and fMRI to determine the specific role of DLPFC function in norm-enforcement behavior. DLPFC rTMS reduced punishment for wrongful acts without affecting blameworthiness ratings, and fMRI revealed punishment-selective DLPFC recruitment, suggesting that these two facets of norm-based decision making are neurobiologically dissociable. Finally, we show that DLPFC rTMS affects punishment decision making by altering the integration of information about culpability and harm. Together, these findings reveal a selective, causal role for DLPFC in norm enforcement: representational integration of the distinct information streams used to make punishment decisions

1, 2-Bis (phenylsulfonyl)-1H-Indole as an Acceptor of Organocuprate Nucleophiles

1,2-Bis(phenylsulfonyl)-1H-indole is a novel example of an electron-deficient indole that undergoes nucleophilic attack at C-3. Though a variety of other organometallic nucleophiles fail to engender nucleophilic substitution, organocuprates produce 3-substituted 2-(phenylsulfonyl)-1H-indoles. These reactions contribute to the growing number of examples of nucleophilic addition to the indole core

Duplications of KIAA1549 and BRAF screening by Droplet Digital PCR from formalin-fixed paraffin-embedded DNA is an accurate alternative for KIAA1549-BRAF fusion detection in pilocytic astrocytomas

Pilocytic astrocytomas represent the most common glioma subtype in young patients and account for 5.4% of all gliomas. They are characterized by alterations in the RAS–MAP kinase pathway, the most frequent being a tandem duplication on chromosome 7q34 involving the BRAF gene, resulting in oncogenic BRAF fusion proteins. BRAF fusion involving the KIAA1549 gene is a hallmark of pilocytic astrocytoma, but it has also been recorded in rare cases of gangliogliomas, 1p/19q co-deleted oligodendroglial tumors, and it is also a common feature of disseminated oligodendroglial-like leptomeningeal neoplasm. In some difficult cases, evidence for KIAA1549-BRAF fusion is of utmost importance for the diagnosis. Moreover, because the KIAA1549-BRAF fusion constitutively activates the MAP kinase pathway, it represents a target for drugs such as MEK inhibitors, and therefore, the detection of this genetic abnormality is highly relevant in the context of clinical trials applying such new approaches. In the present study, we aimed to use the high sensitivity of Droplet Digital PCR (DDPCR™) to predict KIAA1549-BRAF fusion on very small amounts of formalin-fixed paraffin-embedded tissue in routine practice. Therefore, we analyzed a training cohort of 55 pilocytic astrocytomas in which the KIAA1549-BRAF fusion status was known by RNA sequencing used as our gold standard technique. Then, we analyzed a prospective cohort of 40 pilocytic astrocytomas, 27 neuroepithelial tumors remaining difficult to classify (pilocytic astrocytoma versus ganglioglioma or diffuse glioma), 15 dysembryoplastic neuroepithelial tumors, and 18 gangliogliomas. We could demonstrate the usefulness and high accuracy (100% sensitivity and specificity when compared to RNA sequencing) of DDPCR™ to assess the KIAA1549-BRAF fusion from very low amounts of DNA isolated from formalin-fixed paraffin-embedded specimens. BRAF duplication is both necessary and sufficient to predict this fusion in most cases and we propose that this single analysis could be used in routine practice to save time, money, and precious tissue