Characterization of the radiation tolerance of cryogenic diodes for the High Luminosity LHC inner triplet circuit

Cryogenic bypass diodes are part of the baseline powering layout for the circuits of the new Nb3Sn based final focus magnets of the high luminosity Large Hadron Collider. They will protect the magnets against excessive transient voltages during a nonuniform quenching process. The diodes are located inside an extension to the magnet cryostat, operated in superfluid helium and exposed to ionizing radiation. Therefore, the radiation tolerance of different types of diodes has been tested at cryogenic temperatures in CERN’s CHARM irradiation test facility during its 2018 run. The forward bias characteristics, the turn-on voltage and the reverse blocking voltage of each diode were measured weekly at 4.2 K and 77 K, as a function of the accumulated radiation dose. The diodes were submitted to a total dose close to 12 kGy and a 1 MeV neutron equivalent fluence of 2.2×1014  cm−2. After the end of the irradiation program the annealing behavior of the diodes was tested by increasing the temperature slowly to 293 K. This paper describes the experimental setup, the measurement procedure and the analysis of the measurements performed during the irradiation program as well as the results of the annealing study

The Family Name as Socio-Cultural Feature and Genetic Metaphor: From Concepts to Methods

A recent workshop entitled The Family Name as Socio-Cultural Feature and Genetic Metaphor: From Concepts to Methods was held in Paris in December 2010, sponsored by the French National Centre for Scientific Research (CNRS) and by the journal Human Biology. This workshop was intended to foster a debate on questions related to the family names and to compare different multidisciplinary approaches involving geneticists, historians, geographers, sociologists and social anthropologists. This collective paper presents a collection of selected communications

Anaerobic Treatment of Swine Wastewater in Semicontinuous Clayey Support Reactors

Three micronized clayey supports in laboratory-scale tank reactors under mesophilic conditions were studied. From the results obtained in a previous work, the temperature of θ = 25 °C was chosen. The start up and performance of these bioreactors, operating on swine wastewater feed, were also studied. The anaerobic treatment in a semicontinuous regime was carried out. Four stirred tank reactors were used, one of them containing suspended biomass for reference, while the rest contained various suspended micronized clay supports. The supports chosen were zeolite, esmectite, and saponite. The higher removal efficiency (about η COD 70% to 3.6 d HRT) was obtained when HRT increased in saponite and esmectite support reactors. Esmectite support showed the best anaerobic activity of microorganisms (μmax equal to 0.576 d–1). The reactor with zeolite support and the reference (non-support reactor) showed the worst yield in methane. The methane production model proposed by Chen and Hashimoto to achieve an optimum purifying performance was carried out. It accurately predicted the performance of the process and may be used in the design of treatment units

Experimental Setup to Characterize the Radiation Hardness of Cryogenic Bypass Diodes for the HL-LHC Inner Triplet Circuits

For the high luminosity upgrade of the Large Hadron Collider (LHC), it is planned to replace the existing triplet quadrupole magnets with Nb₃Sn quadrupole magnets, which provide a comparable integrated field gradient with a significantly increased aperture. These magnets will be powered through a novel superconducting link based on MgB₂ cables. One option for the powering layout of this triplet circuit is the use of cryogenic bypass diodes, where the diodes are located inside an extension to the magnet cryostat and operated in superfluid helium. Hence, they are exposed to radiation. For this reason the radiation hardness of existing LHC type bypass diodes and more radiation tolerant prototype diodes needs to be tested up to the radiation doses expected at their planned position during their lifetime. A first irradiation test is planned in CERN's CHARM facility starting in spring 2018. Therefore, a cryo-cooler based cryostat to irradiate and test LHC type diodes in-situ has been designed and constructed. This paper will describe the properties of the sample diodes, the experimental roadmap and the setup installed in CHARM. Finally, the first measurement results will be discussed

First Results and Status of the LHC Test String 2

After the commissioning of String 2 Phase1 and the powering of the main circuits in autumn 2001, a short yet vigorous experimental program was carried-out to validate the final design choices for the technical systems of LHC. This program included the investigation of thermo-hydraulics of quenches quench propagation, power converter controls and tracking between power converters, as well as the measurement of currents induced in the beam screen after a quench and crossing the interconnects. Parameters significant for the LHC, such as heat loads, were also measured. During the winter shutdown the String was completed to a full cell with the addition of three pre-series dipoles (Phase 2). After a short description of the layout of Phase 1 and Phase 2, the results of the experiments are presented and the future experimental program is outlined

Holographic flavor on the Higgs branch

In this paper we study the holographic dual, in several spacetime dimensions, of the Higgs branch of gauge theories with fundamental matter. These theories contain defects of various codimensionalities, where the matter fields are located. In the holographic description the matter is added by considering flavor brane probes in the supergravity backgrounds generated by color branes, while the Higgs branch is obtained when the color and flavor branes recombine with each other. We show that, generically, the holographic dual of the Higgs phase is realized by means of the addition of extra flux on the flavor branes and by choosing their appropriate embedding in the background geometry. This suggests a dielectric interpretation in terms of the color branes, whose vacuum solutions precisely match the F- and D-flatness conditions obtained on the field theory side. We further compute the meson mass spectra in several cases and show that when the defect added has codimension greater than zero it becomes continuous and gapless.Comment: 59 pages, 1 figure;v2: references adde

IFNL4 ss469415590 polymorphism is associated with unfavourable clinical and immunological status in HIV-infected individuals

AbstractThe IFNL4 ss469415590 polymorphism, in high linkage disequilibrium with the IL28B rs12979860 variant, has been associated with hepatitis C virus clearance. We evaluated whether ss469415590 is associated with clinical and immunovirological parameters in human immunodeficiency virus-infected subjects. We found an independent association of the IFNL4 ss469415590 polymorphism with higher prevalence of AIDS-defining illnesses and lower CD4 T cell numbers. These results suggest the existence of common host defence mechanisms against different viral infections

Complex spectrum of phenobarbital effects in a mouse model of neonatal hypoxia-induced seizures

Seizures in neonates, mainly caused by hypoxic-ischemic encephalopathy, are thought to be harmful to the brain. Phenobarbital remains the first line drug therapy for the treatment of suspected neonatal seizures but concerns remain with efficacy and safety. Here we explored the short- and long-term outcomes of phenobarbital treatment in a mouse model of hypoxia-induced neonatal seizures. Seizures were induced in P7 mice by exposure to 5% O-2 for 15 minutes. Immediately after hypoxia, pups received a single dose of phenobarbital (25 mg.kg(-1)) or saline. We observed that after administration of phenobarbital seizure burden and number of seizures were reduced compared to the hypoxic period; however, PhB did not suppress acute histopathology. Behavioural analysis of mice at 5 weeks of age previously subjected to hypoxia-seizures revealed an increase in anxiety-like behaviour and impaired memory function compared to control littermates, and these effects were not normalized by phenobarbital. In a seizure susceptibility test, pups previously exposed to hypoxia, with or without phenobarbital, developed longer and more severe seizures in response to kainic acid injection compared to control mice. Unexpectedly, mice treated with phenobarbital developed less hippocampal damage after kainic acid than untreated counterparts. The present study suggests phenobarbital treatment in immature mice does not improve the long lasting functional deficits induces by hypoxia-induced seizures but, unexpectedly, may reduce neuronal death caused by exposure to a second seizure event in later life

Persistent HIV-controllers are more prone to spontaneously clear HCV: a retrospective cohort study.

HIV-controllers have the ability to spontaneously maintain viraemia at low or undetectable levels in the absence of antiretroviral treatment. Furthermore, HIV-controllers seem to have a superior capacity to spontaneously clear hepatitis C virus (HCV) compared to non HIV-controllers. Some of these subjects eventually lose HIV-controller status (transient controllers), whereas some HIV-controllers show a persistent natural HIV control (persistent controllers). We aimed to analyse whether persistent controllers have superior capacity to spontaneously clear HCV compared to transient controllers. We recruited HIV-controllers from January 1981 up to October 2016 with available antibodies to HCV (anti-HCV) data (n = 744). Factors associated with HIV spontaneous control in relation to HCV status were analysed in persistent and transient HIV-controllers with anti-HCV positive (n = 202 and n = 138 respectively) in comparison with 1700 HCV positive non HIV-controllers recruited from January 1981 up to March 2018, bivariate and multivariate analyses, following a logistic regression model, were applied. In addition, the factors related to the loss and time to lose HIV-controller status were explored (n = 744) using Log rank test and Kaplan-Meier curves, in this case the multivariate analysis consisted in a Cox regression model. A higher frequency of HCV spontaneous clearance was found in persistent HIV-controllers (25.5%) compared to non-controllers (10.2%). After adjusting for potential confounders, as sex, age, HIV transmission risk, CD4+ T-cell nadir and time of follow-up, HCV clearance was independently associated with persistent HIV spontaneous control (p = 0.002; OR (95% CI) = 2.573 (1.428 to 4.633)), but not with transient spontaneous control (p = 0.119; 1.589 (0.888 to 2.845)). Furthermore, persistent HIV-controllers were more likely to spontaneously clear the HCV in comparison with transient controllers (p = 0.027; 0.377 (0.159 to 0.893). Finally, not to lose or lengthen the time of losing this control was independently associated with HCV spontaneous clearance (p = 0.010; 0.503 (0.297 to 0.850). This study shows an association between spontaneous persistent HIV-control and HCV spontaneous clearance. The study findings support the idea of preserved immune mechanisms in persistent HIV control implicated in HCV spontaneous clearance. These results highlight persistent HIV-controllers but not transient controllers as a good model of functional HIV cure.This work was supported by the Instituto de Salud Carlos III (research contracts CPII014/00025 to E.R.‐M., and FI14/00431 to L.T.‐D. and research projects PI12/02283, PI16/00684, PI19/01127 to E.R.‐M.) and Red Temática de Investigación Cooperativa en SIDA (Projects RD12/0017/0029, RD12/0017/0031, and RD16/0025/0020 and RD16/0025/0013), which is included in the Acción Estratégica en Salud, Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica 2008 to 2011 and 2013 to 2016, Instituto de Salud Carlos III, Fondos FEDER. E.R.‐M. was supported by Consejería de Salud y Bienestar Social of Junta de Andalucía through the Nicolás Monardes program (C‐0032/17), N Rallón is a Miguel Servet investigator from the Spanish Carlos III Institute of Health (ISCIII), grant CP14/00198, Madrid, Spain and B.D.M. received a grant from The Spanish Ministry of Education (FPU13/02451). Work in CL‐G’s laboratory was supported by grants SAF (2010 to 17226) and (2016‐77894‐R) from MINECO (Spain) and FIS (PI 13/02269, ISCIII) and in part by the RIS‐RETIC grants RD06/006/0036 and RD12/0017/0028 funded by the ISC III‐FEDER. MP has a contract of RIS‐RETIC RD12/0017/0036.S