Present status of development of damping ring extraction kicker system for CLIC

The CLIC damping rings will produce ultra-low emittance beam, with high bunch charge, necessary for the luminosity performance of the collider. To limit the beam emittance blow-up due to oscillations, the pulse power modulators for the damping ring kickers must provide extremely flat, high-voltage pulses: specifications call for a 160 ns duration and a flattop of 12.5 kV, 250 A, with a combined ripple and droop of not more than \pm0.02 %. The stripline design is also extremely challenging: the field for the damping ring kicker system must be homogenous to within \pm0.01 % over a 1 mm radius, and low beam coupling impedance is required. The solid-state modulator, the inductive adder, is a very promising approach to meeting the demanding specifications for the field pulse ripple and droop. This paper describes the initial design of the inductive adder and the striplines of the kicker system.Comment: Proceedings of LCWS'11, International Workshop on Future Linear Colliders, Granada, Spain 26-30 Sept 201

Sampling rare trajectories using stochastic bridges

The numerical quantification of the statistics of rare events in stochastic processes is a challenging computational problem. We present a sampling method that constructs an ensemble of stochastic trajectories that are constrained to have fixed start and end points (so-called stochastic bridges). We then show that by carefully choosing a set of such bridges and assigning an appropriate statistical weight to each bridge, one can focus more processing power on the rare events of a target stochastic process while faithfully preserving the statistics of these rate trajectories. Further, we also compare the stochastic bridges produced using our method to the Wentzel-Kramers-Brillouin (WKB) optimal paths of the target process, derived in the limit of low noise. We see that the paths produced using our method, encoding the full statistics of the process, collapse onto the WKB optimal path as the level of noise is reduced. We propose that our method can be used to judge the accuracy of the WKB approximation at finite levels of noise

Endemic infectious states below the epidemic threshold and beyond herd immunity

In the recent COVID-19 pandemic we assisted at a sequence of epidemic waves intertwined by anomalous fade-outs with periods of low but persistent epidemic prevalence. These long-living epidemic states complicate epidemic control and challenge current modeling approaches as classical epidemic models fail to explain their emergence. Inspired by this phenomenon, we propose a simple mechanism able to reproduce several features observed in real data. Specifically, here we introduce a modification of the Susceptible-Infected-Recovered (SIR) model in a meta-population framework where a small inflow of infected individuals accounts for undetected internal or imported cases. Focusing on a regime where this external seeding is so small that cannot be detected from the analysis of epidemic curves, we find that outbreaks of finite duration percolate in time resulting in overall low but long-living epidemic states below and above the epidemic threshold. Using a two-state description of the local dynamics, we can extract analytical predictions for the phase space. The comparison with epidemic data demonstrates that our model is able to reproduce some critical signatures observed in COVID-19 spreading in England. Finally, our findings defy our understanding of the concept of epidemic threshold and its relationship with outbreaks survival for disease control.Comment: Corrected typo

Cavity-rate analysis applied to the frequency oscillations relaxation in a self-pulsed large-mode-area ytterbium-doped fiber laser.

In this work, an analysis for a self-pulsing behavior within a large-mode-area Ytterbium-doped fibre laser operated as a free running laser is presented. A set of equations that describes the relaxation oscillations frequency by considering a cavity as well as the atomic rate equations were obtained. In here, the behaviour of the self-pulsing is due to the un-pumped fibre section that plays a key role for the saturate absorber. Analytical results depicts that instead of reaching a continuous wave-based regime, the laser output will show pulses with an increasing repetition rate due to the pump power is higher. It is in good agreement with the natural behaviour observed within this fibre laser

Laboratorios interactivos para el aprendizaje experiencial y el manejo integrado del parasitismo gastrointestinal de ovinos y caprinos

The objective was to evaluate the effectiveness of interactive laboratories in generating meaningful learning, modifier of parasite control practices. Interactive laboratories are a methodology for the building of knowledge that facilitate the interaction of sheep and goat farmers with laboratory techniques, on their own farm, to enrich their perceptions about the parasitic process. The research was conducted in the Cauto River Valley, Cuba, in the municipalities of Jiguaní and Bayamo. Fifty sheep and goat farmers were studied. From an interpretative approach, the effect of the activities implemented with the methodology of interactive laboratories on the learning of farmers regarding gastrointestinal strongylosis of small ruminants was evaluated. The participating farmers showed a limited initial understanding of the processes of parasitic infestation based on the lack of previous perceptions about them. The interactive laboratories allowed the creation of key perceptions of the parasitic process, such as etiological agents, sources of infestation and transmission mechanisms; based on a new semantic network with concepts assimilated from visual and lived experience. This allowed the conceptual differentiation of gastrointestinal strongyles with respect to other etiological agents, as well as different stages of the life cycle of these parasites. As a consequence, there was meaningful learning with effective changes in parasite control practices, consistent with preventive strategies.El objetivo fue evaluar la efectividad de los laboratorios interactivos en la generación de un aprendizaje significativo, modificador de las prácticas de control parasitario. Los laboratorios interactivos son una metodología para la construcción de saberes que facilitan la interacción de los criadores de ovinos y caprinos con técnicas de laboratorio, en su propia finca, para enriquecer sus percepciones sobre el proceso parasitario. La investigación se desarrolló en el Valle del Río Cauto, Cuba, en los municipios de Jiguaní y Bayamo. Se estudiaron 50 criadores de ovinos y caprinos. Desde un enfoque interpretativo, se evaluó el efecto de las actividades implementadas con la metodología de laboratorios interactivos sobre el aprendizaje de los criadores respecto a la estrongilosis gastrointestinal de los pequeños rumiantes. Los criadores participantes mostraron un entendimiento inicial limitado de los procesos de infestación parasitaria a partir de la falta de percepciones previas sobre los mismos. Los laboratorios interactivos permitieron la creación de percepciones clave del proceso parasitario, tales como agentes etiológicos, fuentes de infestación y mecanismos de transmisión; sustentadas en una nueva red semántica con conceptos asimilados a partir de la experiencia visual y vivencial. Esto permitió la diferenciación conceptual de los estrongílidos gastrointestinales con respecto a otros agentes etiológicos, así como diferentes estadios del ciclo de vida de estos parásitos. Como consecuencia, se produjo un aprendizaje significativo con cambios efectivos en las prácticas de control parasitario, consistentes con estrategias preventivas

Protective Effects of Short-Chain Fatty Acids on Endothelial Dysfunction Induced by Angiotensin II

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fphys.2020.00277/full#supplementary-materialShort-chain fatty acids (SCFAs) are among the main classes of bacterial metabolic products and are mainly synthesized in the colon through bacterial fermentation. Short-chain fatty acids, such as acetate, butyrate, and propionate, reduce endothelial activation induced by proinflammatory mediators, at least in part, by activation of G protein–coupled receptors (GPRs): GPR41 and GPR43. The objective of the study was to analyze the possible protective effects of SCFAs on endothelial dysfunction induced by angiotensin II (AngII). Rat aortic endothelial cells (RAECs) and rat aortas were incubated with AngII (1 μM) for 6 h in the presence or absence of SCFAs (5–10 mM). In RAECs, we found that AngII reduces the production of nitric oxide (NO) stimulated by calcium ionophore A23187; increases the production of reactive oxygen species (ROS), both from the nicotinamide adenine dinucleotide phosphate oxidase system and the mitochondria; diminishes vasodilator-stimulated phosphoprotein (VASP) phosphorylation at Ser239; reduces GPR41 and GPR43 mRNA level; and reduces the endothelium-dependent relaxant response to acetylcholine in aorta. Coincubation with butyrate and acetate, but not with propionate, increases both NO production and pSer239-VASP, reduces the concentration of intracellular ROS, and improves relaxation to acetylcholine. The beneficial effects of butyrate were inhibited by the GPR41 receptor antagonist, β-hydroxybutyrate, and by the GPR43 receptor antagonist, GLPG0794. Butyrate inhibited the down-regulation of GPR41 and GPR43 induced by AngII, being without effect acetate and propionate. Neither β-hydroxybutyrate nor GLPG0794 affects the protective effect of acetate in endothelial dysfunction. In conclusion, acetate and butyrate improve endothelial dysfunction induced by AngII by increasing the bioavailability of NO. The effect of butyrate seems to be related to GPR41/43 activation, whereas acetate effects were independent of GPR41/43.Comision Interministerial de Ciencia y Tecnologia, Ministerio de Economia y competitividad SAF2017-8489-RJunta de Andalucia CTS164European Union (EU)Ministerio de Economia y competitividad, Instituto de Salud Carlos III (CIBER-CV), Spai

Noncontact Optical Fiber Sensor for Measuring the Refractive Index of Liquids

A noncontact optical fiber sensor for measuring the refractive index of transparent liquids is proposed. It operates by calculating the path of a focused laser beam at 635 nm that travels across the boundaries of a liquid sample. The optical power Fresnel reflections are detected and, subsequently, the refractive index is determined as the ratio between the traveled beam paths when the liquid is deposited versus a reference without the liquid sample. Additionally, a mathematical analysis of the geometrical case is included. The theoretical data from our sensor are in good agreement with the experimental results. The resolution achieved by the sensor is better than 10−3 RIU

Biomass Accumulation and Carbon Storage in Pinus maximinoi, Quercus robur, Quercus rugosa, and Pinus patula from Village- Forests of Chiapas, Mexico

The Frailesca region (Chiapas, Mexico) presents a lack of forest studies and its environmental contribution. This chapter displays a first case study with preliminary research information regarding the identification of main forest trees and rural villages with best potential for biomass production and carbon storage management. Twenty two plots of 500 m2 were selected in 11 villages of the region, in order to identify the main and dominant forest trees species and then to estimate the biomass production and carbon storage in pine (Pinus maximinoi), oak (Quercus robur), holm oak (Quercus rugosa) and Mexican weeping pine (Pinus patula) species. This study shows that the largest accumulation of both biomass and carbon occurred in the pine forests and the lowest in the oak forests. Pine trees showed carbon storage of 516.75 Mg ha−1, followed by holm oaks, with 297.21 Mg ha−1; the species with the lowest value was oak, with 75.02 Mg ha−1. The forests of the 24 de Febrero villages had the highest potential for carbon storage. Deep studies are being conducted in relation to the aboveground biomass, carbon contents in trees stem, branches and leaves, and the relation to biomass dynamics and carbon stocks and other ecological aspects of village-forests

SARS-CoV-2 viral load in nasopharyngeal swabs is not an independent predictor of unfavorable outcome

The aim was to assess the ability of nasopharyngeal SARS-CoV-2 viral load at first patient’s hospital evaluation to predict unfavorable outcomes. We conducted a prospective cohort study including 321 adult patients with confirmed COVID-19 through RT-PCR in nasopharyngeal swabs. Quantitative Synthetic SARS-CoV-2 RNA cycle threshold values were used to calculate the viral load in log10 copies/mL. Disease severity at the end of follow up was categorized into mild, moderate, and severe. Primary endpoint was a composite of intensive care unit (ICU) admission and/or death (n = 85, 26.4%). Univariable and multivariable logistic regression analyses were performed. Nasopharyngeal SARS-CoV-2 viral load over the second quartile (≥ 7.35 log10 copies/mL, p = 0.003) and second tertile (≥ 8.27 log10 copies/mL, p = 0.01) were associated to unfavorable outcome in the unadjusted logistic regression analysis. However, in the final multivariable analysis, viral load was not independently associated with an unfavorable outcome. Five predictors were independently associated with increased odds of ICU admission and/or death: age ≥ 70 years, SpO2, neutrophils > 7.5 × 103/µL, lactate dehydrogenase ≥ 300 U/L, and C-reactive protein ≥ 100 mg/L. In summary, nasopharyngeal SARS-CoV-2 viral load on admission is generally high in patients with COVID-19, regardless of illness severity, but it cannot be used as an independent predictor of unfavorable clinical outcome

Dendritic cell deficiencies persist seven months after SARS-CoV-2 infection

Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)-2 infection induces an exacerbated inflammation driven by innate immunity components. Dendritic cells (DCs) play a key role in the defense against viral infections, for instance plasmacytoid DCs (pDCs), have the capacity to produce vast amounts of interferon-alpha (IFN-α). In COVID-19 there is a deficit in DC numbers and IFN-α production, which has been associated with disease severity. In this work, we described that in addition to the DC deficiency, several DC activation and homing markers were altered in acute COVID-19 patients, which were associated with multiple inflammatory markers. Remarkably, previously hospitalized and nonhospitalized patients remained with decreased numbers of CD1c+ myeloid DCs and pDCs seven months after SARS-CoV-2 infection. Moreover, the expression of DC markers such as CD86 and CD4 were only restored in previously nonhospitalized patients, while no restoration of integrin β7 and indoleamine 2,3-dyoxigenase (IDO) levels were observed. These findings contribute to a better understanding of the immunological sequelae of COVID-19