Spatiotemporal Characterization of Supercontinuum Extending from the Visible to the Mid-Infrared in Multimode Graded-Index Optical Fiber

We experimentally demonstrate that pumping a graded-index multimode fiber with sub-ns pulses from a microchip Nd:YAG laser leads to spectrally flat supercontinuum generation with a uniform bell-shaped spatial beam profile extending from the visible to the mid-infrared at 2500\,nm. We study the development of the supercontinuum along the multimode fiber by the cut-back method, which permits us to analyze the competition between the Kerr-induced geometric parametric instability and stimulated Raman scattering. We also performed a spectrally resolved temporal analysis of the supercontinuum emission.Comment: 5 pages 7 figure

Caracterização hidroambiental de nascentes

As nascentes consistem em um afloramento do lençol freático que dão origem aos fluxos d?água. Essas águas passam a formar a rede de drenagem. Os impactos ambientais negativos, provocados em qualquer porção da bacia podem interferir na quantidade e qualidade da água e, dependendo do impacto, formas ou alternativas diferentes de manejo deverão ser implantadas visando à melhoria do ambiente. Este trabalho teve por objetivo a caracterização das nascentes da bacia do córrego Itanguá, Capão Bonito, SP, Brasil, quanto ao tipo e estado de conservação, assim como a identificação de impactos ambientais negativos presentes. Quanto ao tipo, as nascentes foram classificadas em pontual ou difusa, e o estado de conservação obtido por meio da avaliação macroscópica foi ranqueado em ótimo, bom, razoável, ruim e péssimo. Na bacia foram identificadas 19 nascentes e, das 15 que foram visitadas, nove foram classificadas como pontuais, enquanto que seis foram difusas. Quanto ao estado de conservação, duas foram classificadas como ótimas, 12 como boas e uma como razoável. Também a partir da avaliação macroscópica foi observado que a presença de espécies exóticas, tanto animal (Sus scrofa) como vegetal (Pinus spp.), e a ausência de vegetação nativa na área de preservação permanente foram os impactos ambientais negativos mais frequentes. A metodologia empregada se mostrou eficiente como análise qualitativa visual da situação das nascentes e como fornecedoras de informação para subsidiar ações para a conservação da água na Floresta Nacional de Capão Bonito, SP, Brasil

Definition of priority areas for soil and water conservation in the Itanguá watershed, Capão Bonito, SP state, Brazil.

O uso inadequado dos solos pode provocar erosão e assoreamento dos cursos d?água reduzindo assim a quantidade e a qualidade da água na bacia. A implantação de práticas conservacionistas de solo e a presença de vegetação nativa são ações de fundamental importância para a conservação do solo e água na bacia, uma vez que elas atuam diminuindo o escoamento superficial da água e os processos erosivos. Dessa forma, este estudo teve como objetivo desenvolver um mapa de áreas prioritárias para conservação do solo e da água na bacia hidrográfica do Itanguá, Capão Bonito - SP, com base na caracterização do uso e cobertura do solo e declive da bacia e definir áreas com alta necessidade de implementação de práticas de conservação. Para a elaboração dos mapas temáticos, os planos de informação de uso e cobertura da terra e declividade do terreno foram combinados pelo método booleano em um sistema de informação geográfica. A partir da análise dos dados foram encontradas nove diferentes classes de prioridade para implantação de práticas conservacionistas e seis classes de prioridade para a restauração florestal na área de preservação permanente. Áreas com estrada de terra em região de maior declividade foram identificadas como áreas prioritárias para conservação, inclusive em área de preservação permanente ao longo dos cursos d?água da bacia. O estudo proporciona a primeira avaliação do uso e cobertura da terra no nível da bacia para a Floresta Nacional de Capão Bonito e fornece uma base para identificar prioridades de conservação em toda a bacia de Itanguá

Designed Azolopyridinium Salts Block Protective Antigen Pores In Vitro and Protect Cells from Anthrax Toxin

Background:Several intracellular acting bacterial protein toxins of the AB-type, which are known to enter cells by endocytosis, are shown to produce channels. This holds true for protective antigen (PA), the binding component of the tripartite anthrax-toxin of Bacillus anthracis. Evidence has been presented that translocation of the enzymatic components of anthrax-toxin across the endosomal membrane of target cells and channel formation by the heptameric/octameric PA63 binding/translocation component are related phenomena. Chloroquine and some 4-aminoquinolones, known as potent drugs against Plasmodium falciparium infection of humans, block efficiently the PA63-channel in a dose dependent way.Methodology/Principal Findings:Here we demonstrate that related positively charged heterocyclic azolopyridinium salts block the PA63-channel in the μM range, when both, inhibitor and PA63 are added to the same side of the membrane, the cis-side, which corresponds to the lumen of acidified endosomal vesicles of target cells. Noise-analysis allowed the study of the kinetics of the plug formation by the heterocycles. In vivo experiments using J774A.1 macrophages demonstrated that the inhibitors of PA63-channel function also efficiently block intoxication of the cells by the combination lethal factor and PA63 in the same concentration range as they block the channels in vitro.Conclusions/Significance:These results strongly argue in favor of a transport of lethal factor through the PA63-channel and suggest that the heterocycles used in this study could represent attractive candidates for development of novel therapeutic strategies against anthrax. © 2013 Beitzinger et al

Spatial Division Multiplexing for Multiplex Coherent Anti-Stokes Raman Scattering

We demonstrate how a narrowband pump and a broadband spectrum can be spatially multiplexed by selective coupling them in two distinct modes of a few-mode microstructure fiber. The first mode carries most of the input pump energy, and experiences spectral broadening. Whereas the second mode preserves the narrow bandwidth of the remaining part of the pump. Bimodal propagation, with a power unbalance strongly in favor of the fundamental mode, is naturally obtained by maximizing coupling into the fundamental mode of the fiber. At the fiber output, the nearly monochromatic beam and the supercontinuum carried by the two different modes are combined by a microscope objective, and used as a pump and a Stokes wave for self-referenced multiplex coherent anti-Stokes Raman scattering micro-spectroscopy. The spectral resolution, the signal-to-noise-ratio, and the possible amplification of the remaining pump beam are discussed.Comment: 10 pages, 9 figure

Comparison of detachment in Ohmic plasmas with positive and negative triangularity

Detachment is investigated using core density ramps for lower single null Ohmic L-mode plasmas across a wide range of upper, lower, and total triangularity ($\delta$) in the TCV tokamak. It is universally found that detachment is more difficult to access with negative triangularity (NT) shaping. The outer divertor leg of discharges with $\delta\approx -0.3$ could not be cooled below 5 eV using core density ramps alone. The behavior of the upstream plasma and geometrical divertor effects (e.g. a reduced connection length at negative lower triangularity) do not fully explain the challenges of detaching NT plasmas. Langmuir probe measurements of the target heat flux widths ($\lambda_q$) remained constant within 30% across an upper triangularity scan, while the spreading factor $S$ was found to be lower by up to 50% in NT, indicating a generally lower integral SOL width. An interesting pattern has been observed in the particle balance where the line-averaged core density was typically higher in NT discharges for a given fuelling rate. Conversely, the divertor neutral pressure and integrated particle content were typically lower for the same line-averaged density. This indicates that NT plasmas may be closer to the sheath-limited regime than their PT counterparts, which could explain why NT is more challenging to detach

Constraints on the steady and pulsed very high energy gamma-ray emission from observations of PSR B1951+32/CTB 80 with the MAGIC Telescope

We report on very high energy gamma-observations with the MAGIC Telescope of the pulsar PSR B1951+32 and its associated nebula, CTB 80. Our data constrain the cutoff energy of the pulsar to be less than 32 GeV, assuming the pulsed gamma-ray emission to be exponentially cut off. The upper limit on the flux of pulsed gamma-ray emission above 75 GeV is 4.3*10^-11 photons cm^-2 sec^-1, and the upper limit on the flux of steady emission above 140 GeV is 1.5*10^-11 photons cm^-2 sec^-1. We discuss our results in the framework of recent model predictions and other studies.Comment: 7 pages, 7 figures, replaced with published versio

Identification of a novel zinc metalloprotease through a global analysis of clostridium difficile extracellular proteins

Clostridium difficile is a major cause of infectious diarrhea worldwide. Although the cell surface proteins are recognized to be important in clostridial pathogenesis, biological functions of only a few are known. Also, apart from the toxins, proteins exported by C. difficile into the extracellular milieu have been poorly studied. In order to identify novel extracellular factors of C. difficile, we analyzed bacterial culture supernatants prepared from clinical isolates, 630 and R20291, using liquid chromatography-tandem mass spectrometry. The majority of the proteins identified were non-canonical extracellular proteins. These could be largely classified into proteins associated to the cell wall (including CWPs and extracellular hydrolases), transporters and flagellar proteins. Seven unknown hypothetical proteins were also identified. One of these proteins, CD630_28300, shared sequence similarity with the anthrax lethal factor, a known zinc metallopeptidase. We demonstrated that CD630_28300 (named Zmp1) binds zinc and is able to cleave fibronectin and fibrinogen in vitro in a zinc-dependent manner. Using site-directed mutagenesis, we identified residues important in zinc binding and enzymatic activity. Furthermore, we demonstrated that Zmp1 destabilizes the fibronectin network produced by human fibroblasts. Thus, by analyzing the exoproteome of C. difficile, we identified a novel extracellular metalloprotease that may be important in key steps of clostridial pathogenesis

First bounds on the very high energy gamma-ray emission from Arp 220

Using the Major Atmospheric Gamma Imaging Cherenkov Telescope (MAGIC), we have observed the nearest ultra-luminous infrared galaxy Arp 220 for about 15 hours. No significant signal was detected within the dedicated amount of observation time. The first upper limits to the very high energy $\gamma$-ray flux of Arp 220 are herein reported and compared with theoretical expectations.Comment: Accepted for publication in Ap