3,383 research outputs found
Aberration Corrected Emittance Exchange
Full exploitation of emittance exchange (EEX) requires aberration-free
performance of a complex imaging system including active radio-frequency (RF)
elements which can add temporal distortions. We investigate the performance of
an EEX line where the exchange occurs between two dimensions with normalized
emittances which differ by multiple orders of magnitude. The transverse
emittance is exchanged into the longitudinal dimension using a double dog-leg
emittance exchange setup with a five cell RF deflector cavity. Aberration
correction is performed on the four most dominant aberrations. These include
temporal aberrations that are corrected with higher order magnetic optical
elements located where longitudinal and transverse emittance are coupled. We
demonstrate aberration-free performance of an EEX line with emittances
differing by four orders of magnitude, \textit{i.e.} an initial transverse
emittance of 1~pm-rad is exchanged with a longitudinal emittance of 10~nm-rad
Nano-modulated electron beams via electron diffraction and emittance exchange for coherent x-ray generation
We present a new method for generation of relativistic electron beams with
current modulation on the nanometer scale and below. The current modulation is
produced by diffracting relativistic electrons in single crystal Si,
accelerating the diffracted beam and imaging the crystal structure, then
transferring the image into the temporal dimension via emittance exchange. The
modulation period can be tuned by adjusting electron optics after diffraction.
This tunable longitudinal modulation can have a period as short as a few
angstroms, enabling production of coherent hard x-rays from a source based on
inverse Compton scattering with total accelerator length of approximately ten
meters. Electron beam simulations from cathode emission through diffraction,
acceleration and image formation with variable magnification are presented
along with estimates of the coherent x-ray output properties
Cosmic rays 10Be biennal data and their relationship to aurorae and sunspots
The galactic cosmic ray (C.R.) variations which should give information on three dimensional aspects of the heliospheric magnetic fields and on the solar wind, which modulate their influx into the Solar System were studied. In order to decode the information from the C.R. series it is necessary to know the mechanisms through which the modulation is produced. It it clear that a balance of effects with sources at different heliospheric latitudes results in the modulated C.R. intensity. It is found that the modulation of 10Be in polar ice may be due to at least two main contributions: (1) negative and in phase with the Solar flare activity modulating the cosmic ray flux in Forbush-type decreases, and (2) positive in phase with the appearance of large wind streams situated at both polar coronal holes. It is found that the high heliolatitude activity is related to a stable periodicity of 11.1y whereas the low heliolatitude activity contributes to the wondering of the solar cycles
Measures taken to reduce the risk of West Nile virus transmission by transplantation in Italy.
Estrogen-dependent dynamic profile of eNOS-DNA associations in prostate cancer
In previous work we have documented the nuclear translocation of endothelial NOS (eNOS) and its participation in combinatorial complexes with Estrogen Receptor Beta (ERβ) and Hypoxia Inducible Factors (HIFs) that determine localized chromatin remodeling in response to estrogen (E2) and hypoxia stimuli, resulting in transcriptional regulation of genes associated with adverse prognosis in prostate cancer (PCa). To explore the role of nuclear eNOS in the acquisition of aggressive phenotype in PCa, we performed ChIP-Sequencing on chromatin-associated eNOS from cells from a primary tumor with poor outcome and from metastatic LNCaP cells. We found that: 1. the eNOS-bound regions (peaks) are widely distributed across the genome encompassing multiple transcription factors binding sites, including Estrogen Response Elements. 2. E2 increased the number of peaks, indicating hormone-dependent eNOS re-localization. 3. Peak distribution was similar with/without E2 with ≈ 55% of them in extragenic DNA regions and an intriguing involvement of the 5′ domain of several miRs deregulated in PCa. Numerous potentially novel eNOS-targeted genes have been identified suggesting that eNOS participates in the regulation of large gene sets. The parallel finding of downregulation of a cluster of miRs, including miR-34a, in PCa cells associated with poor outcome led us to unveil a molecular link between eNOS and SIRT1, an epigenetic regulator of aging and tumorigenicity, negatively regulated by miR-34a and in turn activating eNOS. E2 potentiates miR-34a downregulation thus enhancing SIRT1 expression, depicting a novel eNOS/SIRT1 interplay fine-tuned by E2-activated ER signaling, and suggesting that eNOS may play an important role in aggressive PCa
Recent results and new hardware developments for protein crystal growth in microactivity
Protein crystal growth experiments have been performed on 16 space shuttle missions since April, 1985. The initial experiments utilized vapor diffusion crystallization techniques similar to those used in laboratories for earth-based experiments. More recent experiments have utilized temperature induced crystallization as an alternative method for growing high quality protein crystals in microgravity. Results from both vapor diffusion and temperature induced crystallization experiments indicate that proteins grown in microgravity may be larger, display more uniform morphologies, and yield diffraction data to significantly higher resolutions than the best crystals of these proteins grown on earth
Las Carabidae (Insecta, Coleoptera) de los suelos del Bajo Delta Bonaerense del Río Paraná : Estado actual de su conocimiento
Fil: Cicchino, Armando Conrado. División Entomología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Nanni, Analía S.. Instituto de Investigación e Ingeniería Ambiental. Universidad Nacional de San Martín; ArgentinaFil: Fracassi, Natalia G.. EEA INTA. Campana; ArgentinaFil: Quintana, Rubén D.. Laboratorio de Ecología Regional. Departamento de Ecología, Genética y Evolución. Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires; Argentin
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