A compact design for velocity-map imaging energetic electrons and ions

We present a compact design for a velocity-map imaging spectrometer for energetic electrons and ions. The standard geometry by Eppink and Parker [A. T. J. B. Eppink and D. H. Parker, Rev. Sci. Instrum. 68, 3477 (1997)] is augmented by just two extended electrodes so as to realize an additional einzel lens. In this way, for a maximum electrode voltage of 7 kV we experimentally demonstrate imaging of electrons with energies up to 65 eV. Simulations show that energy acceptances of <270 and <1,200 eV with an energy resolution of dE / E <5% are achievable for electrode voltages of <20 kV when using diameters of the position-sensitive detector of 42 and 78 mm, respectively

À propos de la rhétorique des images monétaires des peuples du Centre-Est de la Gaule

Les monnaies gauloises fournissent une documentation iconographique de premier ordre concernant le second Âge du Fer. Cet article rend compte de nos recherches de thèse de doctorat. Il aborde, en croisant iconographie, archéologie et textes, la composition du discours transcrit par les images monétaires et son évolution sur près de trois siècles dans le Centre-Est de la Gaule. Les images monétaires nous renseignent sur la pensée et les codes des pouvoirs émetteurs : leur mode de représentation et la manière dont ils se situent dans leur environnement se révélant alors une source d’étude anthropologique.Celtic coins provide excellent iconographic documentation relating to the second Iron Age. This paper reports research made for a PhD thesis which, through iconography, archaeology and texts, studied images on coins and their evolution over nearly three centuries in East Central Gaul. Coin imagery informs us about the thought and the codes used by the elites, how they represented themselves in society and the way they perceived themselves. It also reveals the importance of coinage to anthropological study.Die keltischen Münzen bieten eine ausgezeichnete ikonographische Dokumentation für die jüngere Eisenzeit. Dieser Artikel ist eine Zusammenfassung unserer Doktorarbeit. Anhand der Ikonographie, der Archäologie und der Texte untersuchen wir die Münzbildnisse und ihre Entwicklung über 300 Jahre in Mittel-Ostgallien. Die Münzbildnisse informieren uns über die Vorstellungen und die Selbstdarstellung der münzprägenden Eliten. Die Darstellungsweise und die Art, wie sie sich in ihre Umgebung einordnen sind eine Quelle für die anthropologische Forschung

À propos de la rhétorique des images monétaires des peuples du Centre-Est de la Gaule

Les monnaies gauloises fournissent une documentation iconographique de premier ordre concernant le second Âge du Fer. Cet article rend compte de nos recherches de thèse de doctorat. Il aborde, en croisant iconographie, archéologie et textes, la composition du discours transcrit par les images monétaires et son évolution sur près de trois siècles dans le Centre-Est de la Gaule. Les images monétaires nous renseignent sur la pensée et les codes des pouvoirs émetteurs : leur mode de représentation et la manière dont ils se situent dans leur environnement se révélant alors une source d’étude anthropologique.Celtic coins provide excellent iconographic documentation relating to the second Iron Age. This paper reports research made for a PhD thesis which, through iconography, archaeology and texts, studied images on coins and their evolution over nearly three centuries in East Central Gaul. Coin imagery informs us about the thought and the codes used by the elites, how they represented themselves in society and the way they perceived themselves. It also reveals the importance of coinage to anthropological study.Die keltischen Münzen bieten eine ausgezeichnete ikonographische Dokumentation für die jüngere Eisenzeit. Dieser Artikel ist eine Zusammenfassung unserer Doktorarbeit. Anhand der Ikonographie, der Archäologie und der Texte untersuchen wir die Münzbildnisse und ihre Entwicklung über 300 Jahre in Mittel-Ostgallien. Die Münzbildnisse informieren uns über die Vorstellungen und die Selbstdarstellung der münzprägenden Eliten. Die Darstellungsweise und die Art, wie sie sich in ihre Umgebung einordnen sind eine Quelle für die anthropologische Forschung

Management of Low-Grade Glioma

The optimal management of patients with low-grade glioma (LGG) is controversial. The controversy largely stems from the lack of well-designed clinical trials with adequate follow-up to account for the relatively long progression-free survival and overall survival of patients with LGG. Nonetheless, the literature increasingly suggests that expectant management is no longer optimal. Rather, there is mounting evidence supporting active management including consideration of surgical resection, radiotherapy, chemotherapy, molecular and histopathologic characterization, and use of modern imaging techniques for monitoring and prognostication. In particular, there is growing evidence favoring extensive surgical resection and increasing interest in the role of chemotherapy (especially temozolomide) in the management of these tumors. In this review, we critically analyze emerging trends in the literature with respect to management of LGG, with particular emphasis on reports published during the past year

Single-Shot Electron Imaging of Dopant-Induced Nanoplasmas

We present single-shot electron velocity-map images of nanoplasmas generated from doped helium nanodroplets and neon clusters by intense near-infrared and mid-infrared laser pulses. We report a large variety of signal types, most crucially depending on the cluster size. The common feature is a two-component distribution for each single-cluster event: a bright inner part with nearly circular shape corresponding to electron energies up to a few eV, surrounded by an extended background of more energetic electrons. The total counts and energy of the electrons in the inner part are strongly correlated and follow a simple power-law dependence. Deviations from the circular shape of the inner electrons observed for neon clusters and large helium nanodroplets indicate non-spherical shapes of the neutral clusters. The dependence of the measured electron energies on the extraction voltage of the spectrometer indicates that the evolution of the nanoplasma is significantly affected by the presence of an external electric field. This conjecture is confirmed by molecular dynamics simulations, which reproduce the salient features of the experimental electron spectra.The authors are grateful for financial support from the Deutsche Forschungsgemeinschaft (DFG) within the project MU 2347/12-1 and STI 125/22-2 in the frame of the Priority Programme 1840 ‘Quantum Dynamics in Tailored Intense Fields’, from the Carlsberg Foundation and the SPARC Programme, MHRD, India. The ELI-ALPS Project (GINOP-2.3.6-15-2015-00001) is supported by the European Union and co-financed by the European Regional Development Fund. AH is grateful for financial support from the Basque Government (Project Reference No. IT1254-19) and from the Spanish Ministerio de Economia y Competividad (Reference No. CTQ2015-67660-P). Computational and manpower support provided by IZO-SGI SG Iker of UPV/EHU and European funding (EDRF and ESF) is gratefully acknowledged

Optically-guided frameless linac-based radiosurgery for brain metastases: clinical experience

The purpose of this study was to describe our clinical experience using optically-guided linear accelerator (linac)-based frameless stereotactic radiosurgery (SRS) for the treatment of brain metastases. Sixty-five patients (204 lesions) were treated between 2005 and 2008 with frameless SRS using an optically-guided bite-block system. Patients had a median of 2 lesions (range, 1–13). Prescription dose ranged from 14 to 22 Gy (median, 18 Gy) and was given in a single fraction. Clinical and radiographic evaluation occurred every 2–4 months following treatment. At a median follow-up of 6.2 months, actuarial survival at 12 months was 40% [95% confidence interval (CI), 28–52). Of 135 lesions that were evaluable for local control (LC), 119 lesions (88%) did not show evidence of progression. Actuarial 12 month LC was 76% (95% CI, 66–86). Tumors ≤2 cm in size had a better 12 month LC rate (81% vs. 36%, P = 0.017) than those >2 cm. Adverse events occurred in three patients (5%). Optically-guided linac-based frameless SRS can produce clinical outcomes that compare favorably to frame-based techniques. As this technique is convenient to use and allows for the uncomplicated delivery of hypofractionated radiotherapy, frameless SRS will likely have an increasingly important role in the management of brain metastases

Malignant Tumors of the Central Nervous System

Malignant tumors of the central nervous system in adults comprise a heterogeneous group of malignancies, the largest subgroups comprising astrocytomas, ependymomas, and oligodendrogliomas. Glioblastomas are the most common tumor type, and they have dismal prognosis. Due to differences in cell type of origin, as well as pathogenesis, it is plausible that their etiology also differs between tumor types. The etiology of malignant CNS tumors is largely unknown and no occupational risk factors have been definitively identified. High doses of ionizing radiation increase the risk, but in occupational settings the dose levels appear too small to result in discernible excesses. Several studies have assessed possible effect of extremely low frequency and radiofrequency electromagnetic fields, but the results are inconsistent. Increased brain tumor risk has been reported in agricultural workers, but no specific exposure has been linked to them. Pesticides have been analyzed in several studies without showing a clear increase in risk.acceptedVersionPeer reviewe