RHESSI Results -- Time For a Rethink?

Hard X-rays and gamma-rays are the most direct signatures of energetic electrons and ions in the sun's atmosphere which is optically thin at these energies and their radiation involves no coherent processes. Being collisional they are complementary to gyro-radiation in probing atmospheric density as opposed to magnetic field and the electrons are primarily 10--100 keV in energy, complementing the (>100 keV) electrons likely responsible for microwave bursts. The pioneering results of the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) are raising the first new major questions concerning solar energetic particles in many years. Some highlights of these results are discussed -- primarily around RHESSI topics on which the authors have had direct research involvement -- particularly when they are raising the need for re-thinking of entrenched ideas. Results and issues are broadly divided into discoveries in the spatial, temporal and spectral domains, with the main emphasis on flare hard X-rays/fast electrons but touching also on gamma-rays/ions, non-flare emissions, and the relationship to radio bursts.Comment: Proceedings CESRA Workshop 2004: "The High Energy Solar Corona: Waves, Eruptions, Particles", Lecture Notes in Physics, 2006 (accepted

Updated precision measurement of the average lifetime of B hadrons

The measurement of the average lifetime of B hadrons using inclusively reconstructed secondary vertices has been updated using both an improved processing of previous data and additional statistics from new data. This has reduced the statistical and systematic uncertainties and gives \tau_{\mathrm{B}} = 1.582 \pm 0.011\ \mathrm{(stat.)} \pm 0.027\ \mathrm{(syst.)}\ \mathrm{ps.} Combining this result with the previous result based on charged particle impact parameter distributions yields \tau_{\mathrm{B}} = 1.575 \pm 0.010\ \mathrm{(stat.)} \pm 0.026\ \mathrm{(syst.)}\ \mathrm{ps.

Limits on the production of scalar leptoquarks from Z (0) decays at LEP

A search has been made for pairs and for single production of scalar leptoquarks of the first and second generations using a data sample of 392000 Z0 decays from the DELPHI detector at LEP 1. No signal was found and limits on the leptoquark mass, production cross section and branching ratio were set. A mass limit at 95% confidence level of 45.5 GeV/c2 was obtained for leptoquark pair production. The search for the production of a single leptoquark probed the mass region above this limit and its results exclude first and second generation leptoquarks D0 with masses below 65 GeV/c2 and 73 GeV/c2 respectively, at 95% confidence level, assuming that the D0lq Yukawa coupling alpha(lambda) is equal to the electromagnetic one. An upper limit is also given on the coupling alpha(lambda) as a function of the leptoquark mass m(D0)

Different clonal origin of bilateral papillary thyroid carcinoma, with a review of the literature

Papillary thyroid carcinoma (PTC) often presents with two or more anatomically separate foci. A longstanding argument is whether this multifocality is the result of multiple independent tumors (" multicentricity") or of intrathyroidal spread originating from a single tumor mass, presumably through permeation of intrathyroidal lymph vessels. We reexamined this issue with a clonality assay and compared our results with those in the literature. A total of 27 nodules from 11 female patients with bilateral PTC treated with total thyroidectomy were investigated for clon-ality using the HUMARA assay. Eight of 11 cases were informative (72.7%). All but one of tumor foci showed a monoclonal population. The outlier sample gave a value indicative of balanced X-inactivation in one nodule. The monoclonality was concordant in three patients, discordant in three, and mixed in two (with both concordant and discordant results). Interestingly, in both of the latter cases (composed of over two samples per case), the contralateral nodules were discordant. Moreover, all four ipsilateral nodules were concordant. The results of our study suggest that some cases of multifocal PTC are the result of true multicentricity, whereas others are the consequence of intrathyroid spread by an originally single tumor mass. These conclusions support those made in the past years on the basis of morphologic considerations. Specifically, the incidental finding of two or more microscopic foci of PTC widely separate from each other was felt to favor multicentricity, whereas the finding of multiple ipsilateral foci of PTC within vascular spaces, often accompanied by multiple lymph node metastases, suggested intrathy-roid spread; the most striking manifestation of this phenomenon being seen in the diffuse sclerosing variant of PTC

A ‘VISUAL’ APPROACH TO MENANDER - (A.K.) Petrides Menander, New Comedy and the Visual. Pp. xii + 322, ills. Cambridge: Cambridge University Press, 2014. Cased, £65, US$99. ISBN: 978-1-107-06843-8.

High-energy X-rays and gamma-rays from solar flares were discovered just over fifty years ago. Since that time, the standard for the interpretation of spatially integrated flare X-ray spectra at energies above several tens of keV has been the collisional thick-target model. After the launch of the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in early 2002, X-ray spectra and images have been of sufficient quality to allow a greater focus on the energetic electrons responsible for the X-ray emission, including their origin and their interactions with the flare plasma and magnetic field. The result has been new insights into the flaring process, as well as more quantitative models for both electron acceleration and propagation, and for the flare environment with which the electrons interact. In this article we review our current understanding of electron acceleration, energy loss, and propagation in flares. Implications of these new results for the collisional thick-target model, for general flare models, and for future flare studies are discussed.Comment: This is an article from a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

Desempenho reprodutivo e zootécnico e deposição de lipídios nos hepatócitos de fêmeas de tilápia-do-nilo alimentadas com rações de diversos níveis energéticos Reproductive and animal performance and lipids deposition in hepatocytes for Nile tilapia females fed different levels of energy in the ration

Um experimento foi conduzido com o objetivo de avaliar os desempenhos reprodutivo e zootécnico e a deposição de lipídios no tecido hepático de fêmeas de tilápia-do-nilo alimentadas com rações contendo diferentes níveis de energia digestível, obtidos pela inclusão de óleo de soja. Foram utilizados 100 reprodutores e 300 reprodutoras, distribuídos em delineamento inteiramente casualizado com cinco tratamentos e quatro repetições. Os reprodutores, machos e fêmeas, foram alimentados com rações contendo, por quilograma, 35% de proteína bruta e 2.700, 2.950, 3.200, 3.450 ou 3.700 kcal de energia digestível. Os animais foram mantidos em hapas por 93 dias. O desempenho reprodutivo e zootécnico não foi influenciado pelos níveis energéticos das rações, o que pode estar relacionado ao curto período de tempo de alimentação com as dietas experimentais. Contudo, o aumento nos níveis de energia teve efeito linear nas deposições lipídicas nos hepatócitos. Desta forma, os níveis crescentes de energia digestível nas rações fornecidas às fêmeas de tilápia-do-nilo, obtidos pela inclusão de óleo de soja, apenas aumentam o tempo de sobrevivência das larvas ao jejum e a deposição de lipídios nos hepatócitos das fêmeas.<br>The experiment was carried out to evaluate the reproductive and animal performance and lipids deposition in the liver tissue of the Nile tilapia female, fed diets containing different levels of digestible energy, obtained by soybean oil inclusion. Three hundred breeding females and 100 breeding males were used, distributed in a completely randomized design with five treatments and four replications. The broods were fed diets containing 35% crude protein and 2,700; 2,950; 3,200; 3,450 and 3,700 kcal energy digestible/kg feed. The animals were stocked in hapas for 93 days. The reproductive and animal performance were not influenced by the energy levels. These results may be associated with the short period of time that the brood were fed the experimental diets. However, increasing energy levels caused a linear increase in lipids inclusions in hepatocytes. Thus, the increasing levels of digestible energy provided to Nile tilapia females, obtained by including soybean oil, only promoted increased lipid deposition in hepatocytes