Numerical and experimental studies to model and reduce the impedance in the CERN Super Proton Synchrotron (SPS)

Intensity-driven beam instabilities are studied in simulations with a refined impedance model and in experimental measurements for this thesis. The High Luminosity Large Hadron Collider (HL-LHC) project at CERN aims for an increase in the integrated luminosity in the Large Hadron Collider (LHC). To achieve this goal the LHC injector chain has to be upgraded. The last LHC injector, the Super Proton Synchrotron (SPS), intends to accelerate beams with twice the present intensity.Intensitätsgetriebene Strahlinstabilitäten werden in dieser Arbeit mit einem vervollständigten Impedanzmodell in Teilchensimulationen und in experimentellen Messungen untersucht. Das High Luminosity Large Hadron Collider (HL-LHC)-Projekt am CERN hat eine Erhöhung der integrierten Luminosität im Large Hadron Collider (LHC) als Ziel. Um dieses Ziel zu erreichen, müssen auch die Vorbeschleuniger des LHC aufgerüstet werden. Der direkte LHC Injektor, das Super Proton Synchrotron (SPS), soll Teilchenstrahlen mit der doppelten derzeitigen Intensität beschleunigen

NOVAS FORMAS DE ORGANIZAÇÃO NO SETOR PÚBLICO E SUAS CONSEQUÊNCIAS PARA A EDUCAÇÃO À DISTÂNCIA: UMA REVISÃO SISTEMÁTICA DE LITERATURA

O presente estudo de caso pretende realizar uma revisão sistemática da literatura científica sobre o tema da gestão no setor público e educação à distância. Por conseguinte, pretende também entender a trajetória da educação a distância permitindo absorver suas diferentes faces e sua relação com diferentes contextos educacionais, auxiliando na previsão do futuro, diante do contexto educacional que se apresenta o país. Nesse sentido, foram analisados trabalhos de pesquisa (Dissertações) da Universidade Federal de Santa Catarina. O objetivo desta pesquisa consiste em identificar a lacuna teórica sobre o tema de gestão da educação à distância em instituições de ensino superior do setor público. A natureza desta pesquisa é básica, classifica-se como qualitativa, uma vez que não requer o uso de métodos e técnicas estatísticas. O ambiente natural é a fonte direta para coleta de dados e o pesquisador é o instrumento-chave. É descritiva. O processo e seu significado são os focos principais de abordagem. Quanto aos fins, possui caráter descritivo. Quanto aos meios, será utilizada a Pesquisa Bibliográfica. A amostra será composta por seis dissertações na área de Educação à Distância dos cursos de Mestrado em Administração e Administração Universitária da Universidade Federal de Santa Catarina. Os instrumentos de coleta de dados a serem utilizados serão referências bibliográficas e pesquisa documental como fonte de dados primários. Paralelamente neste artigo serão revisados aspectos sobre EAD desde um histórico mundial e brasileiro, as diferentes definições sobre EAD apresentadas, assim como os aspectos positivos e negativos destacados nos trabalhos analisados. Por fim, será apresentada uma discussão sobre o cenário atual e perspectivas futuras da EAD no Brasil

Turbulent self-organized criticality

In the prototype sandpile model of self-organized criticality time series obtained by decomposing avalanches into waves of toppling show intermittent fluctuations. The q-th moments of wave size differences possess local multiscaling and global simple scaling regimes analogous to those holding for velocity structure functions in fluid turbulence. The correspondence involves identity of a basic scaling relation and of the form of relevant probability distributions. The sandpile provides a qualitative analog of many features of turbulent phenomena.Comment: Revised version. 5 RevTex pages and 4 postscript figure

Retrieval of phase relation and emission profile of quantum cascade laser frequency combs

The major development recently undergone by quantum cascade lasers has effectively extended frequency comb emission to longer-wavelength spectral regions, i.e. the mid and far infrared. Unlike classical pulsed frequency combs, their mode-locking mechanism relies on four-wave mixing nonlinear processes, with a temporal intensity profile different from conventional short-pulses trains. Measuring the absolute phase pattern of the modes in these combs enables a thorough characterization of the onset of mode-locking in absence of short-pulses emission, as well as of the coherence properties. Here, by combining dual-comb multi-heterodyne detection with Fourier-transform analysis, we show how to simultaneously acquire and monitor over a wide range of timescales the phase pattern of a generic frequency comb. The technique is applied to characterize a mid-infrared and a terahertz quantum cascade laser frequency comb, conclusively proving the high degree of coherence and the remarkable long-term stability of these sources. Moreover, the technique allows also the reconstruction of electric field, intensity profile and instantaneous frequency of the emission.Comment: 20 pages. Submitted to Nature Photonic

Effects of Endotoxin and Catecholamines on Hepatic Mitochondrial Respiration

Catecholamines are frequently used in sepsis, but their interaction with mitochondrial function is controversial. We incubated isolated native and endotoxin-exposed swine liver mitochondria with either dopamine, dobutamine, noradrenaline or placebo for 1h. Mitochondrial State 3 and 4 respiration and their ratio (RCR) were determined for respiratory chain complexes I, II and IV. All catecholamines impaired glutamate-dependent RCR (p = 0.046), predominantly in native mitochondria. Endotoxin incubation alone induced a decrease in glutamate-dependent RCR compared to control samples (p = 0.002). We conclude that catecholamines and endotoxin impair the efficiency of mitochondrial complex I respiration in vitr

Splanchnic Vasoregulation After Major Abdominal Surgery in Pigs

Background: Unrecognized reduction of blood supply to intestinal organs is associated with significant postoperative morbidity in abdominal surgery. The aim of this study was to determine whether—in the absence of hypovolemia—intestinal hypoperfusion as a result of blood flow redistribution occurs after abdominal surgery. Methods: Standardized operative trauma was induced in 14 healthy pigs. Systemic, regional, and local blood flow, intestinal and gastric intraluminal-to-end-tidal pCO2 gradients representing mucosal perfusion, and oxygen transport variables were measured for 10 postoperative hours. Normovolemia was maintained using continuous infusion of Ringer's lactate and additional boluses of colloids in response to blood pressure, pulmonary wedge pressure, and urinary output. Results: Postoperative blood flow was significantly increased in the celiac trunk (76% increase [percentage of baseline flow], p=0.003) and the hepatic (136% increase, p=0.002) and splenic (36% increase, p=0.025) arteries. Blood flow was significantly decreased in the mesenteric artery (25% decrease, p=0.007) and portal vein (13% decrease, p=0.028). Carotid and renal artery blood flow remained unchanged. Conclusions: Maintenance of normovolemia is insufficient to protect from intestinal hypoperfusion after abdominal surgery. Postoperative redistribution of cardiac output results in decreased intestinal and increased hepatic and splenic arterial blood flo

The Phosphate Transporter PiT1 (Slc20a1) Revealed As a New Essential Gene for Mouse Liver Development

BACKGROUND: PiT1 (or SLC20a1) encodes a widely expressed plasma membrane protein functioning as a high-affinity Na(+)-phosphate (Pi) cotransporter. As such, PiT1 is often considered as a ubiquitous supplier of Pi for cellular needs regardless of the lack of experimental data. Although the importance of PiT1 in mineralizing processes have been demonstrated in vitro in osteoblasts, chondrocytes and vascular smooth muscle cells, in vivo evidence is missing. METHODOLOGY/PRINCIPAL FINDINGS: To determine the in vivo function of PiT1, we generated an allelic series of PiT1 mutations in mice by combination of wild-type, hypomorphic and null PiT1 alleles expressing from 100% to 0% of PiT1. In this report we show that complete deletion of PiT1 results in embryonic lethality at E12.5. PiT1-deficient embryos display severely hypoplastic fetal livers and subsequent reduced hematopoiesis resulting in embryonic death from anemia. We show that the anemia is not due to placental, yolk sac or vascular defects and that hematopoietic progenitors have no cell-autonomous defects in proliferation and differentiation. In contrast, mutant fetal livers display decreased proliferation and massive apoptosis. Animals carrying two copies of hypomorphic PiT1 alleles (resulting in 15% PiT1 expression comparing to wild-type animals) survive at birth but are growth-retarded and anemic. The combination of both hypomorphic and null alleles in heterozygous compounds results in late embryonic lethality (E14.5-E16.5) with phenotypic features intermediate between null and hypomorphic mice. In the three mouse lines generated we could not evidence defects in early skeleton formation. CONCLUSION/SIGNIFICANCE: This work is the first to illustrate a specific in vivo role for PiT1 by uncovering it as being a critical gene for normal developmental liver growth

Stochastic ODEs and stochastic linear PDEs with critical drift: regularity, duality and uniqueness

Linear stochastic transport and continuity equations with drift in critical Lp spaces are considered. A result of Sobolev regularity of solutions is proved, false for the corresponding deterministic equations. Thus noise prevents shocks for transport equation and singularities in the density for continuity equation, starting from smooth initial conditions. The technique needed to reach the critical case is new and based on parabolic equations satis ed by moments of rst derivatives of the solution, opposite to previous works based on stochastic ows. The approach extends to higher order derivatives under more regularity of the drift term. By a duality approach, the results are then applied to prove uniqueness of weak solutions to linear stochastic continuity and transport equations and certain well posedness results for the associated stochastic di erential equation (sDE) (roughly speaking, existence and uniqueness of ows and their C regularity, strong uniqueness for the sDE when the initial datum has di use law). Finally, we show two types of examples: on the one hand, we present well- posed sDEs, when the corresponding ODEs are ill-posed, and on the other hand, we give a counterexample in the supercritical case.no