Determining the Time Constant of Arcs at Arbitrary Current Levels

For the development and optimization of gas circuit breakers and switchgear, a detailed understanding of the arc related processes is of great importance. Ideally, analytical or numerical models with predicitive capability can be found and used during the design process preceding costly and time-consuming experiments.In the present contribution, we report on a novel measurement and evaluation technique to determine the thermal arc time constant ("thermal inertia") that is commonly used in simple black-box models to describe the arc's dynamical properties. The method is introduced and applied to example arcs under varying blow gas conditions in air

(Des)encuentros: La ficción televisiva a debate

Desde hace algún tiempo, y curiosamente coincidiendo con el centenario de su nacimiento, muchas voces vienen anunciando la inevitable muerte del cine. Las cifras del torrencial vaciado de las salas son irrebatibles, y múltiples las posibles razones que se congregan para dar con su explicación. El precio de las entradas, la comodidad del consumo doméstico, la piratería, e incluso la baja calidad de los productos que se estrenan en las salas comerciales, son motivos comúnmente defendidos. Sin embargo, todos aquellos que con premura ansiaban encontrar su cadáver no logran encontrarlo, y es que puede que el cine no haya muerto, sino que haya cambiado de aspecto. Así, las ideas del mercado hollywoodiense, al menos las más arriesgadas y diferentes —que casi por norma suelen resultar ser las más interesantes desde un punto de vista científico-crítico— debían buscar una plataforma a través de la cual poder manifestarse. Y esa plataforma la encontró el cine en su hermana pequeña —por edad—: la televisión.For some time, and curiously coinciding with the centenary of its birth, many voices have announced the inevitable death of cinema. Figures from the huge emptying of cinemas are irrefutable, and the possible reasons that explain this fact are numerous. The ticket prices, the comfort of home consumption, hacking, and even the low quality of the products that are shown in cinemas are commonly defended reasons. However, those who were anxious to find cinema’s deceased body can’t find it yet; and that is because maybe cinema is not already dead, but has changed in appearance instead. Thus, the ideas of the Hollywood market, at least the most daring and different, which almost as a rule tend to be the most interesting ones from a scientific and critical point of view, must find a platform through which they will be able to manifest themselves. And cinema has found this platform in its little sister (due to its age): televisio

Influence of Ablation on Differential Arc Resistance

The influence of ablation on the du/di behavior of an arc in a model gas circuit breaker was examined. Specifically the transition from a state without ablation in the nozzle towards states with ablation was of interest, since prior work indicated that for high currents the voltage becomes constant or du/di gets even positive if ablation is present. Measurements with different blow pressures and rectangular DC currents of varying amplitude were compared, using PMMA-nozzles and dry air as blowing gas. Ablation was measured by weighing the nozzle, scanning the cross section, and using a coordinate measuring machine. The results agreed well, and confirmed that higher pressure shifts the du/di curve towards more favorable values

A robust wavelet-based approach for dominant frequency analysis of atrial fibrillation in body surface signals

This is an author-created, un-copyedited versíon of an article published in Physiological Measurement. IOP Publishing Ltd is not responsíble for any errors or omissíons in this versíon of the manuscript or any versíon derived from it. The Versíon of Record is available online at https://doi.org/10.1088/1361-6579/ab97c1.[EN] Objective: Atrial dominant frequency (DF) maps undergoing atrial fibrillation (AF) presented good spatial correlation with those obtained with the non-invasive body surface potential mapping (BSPM). In this study, a robust BSPM-DF calculation method based on wavelet analysis is proposed. Approach: Continuous wavelet transform along 40 scales in the pseudo-frequency range of 3¿30 Hz is performed in each BSPM signal using a Gaussian mother wavelet. DFs are estimated from the intervals between the peaks, representing the activation times, in the maximum energy scale. The results are compared with the traditionally widely applied Welch periodogram and the robustness was tested on different protocols: increasing levels of white Gaussian noise, artificial DF harmonics presence and reduction in the number of leads. A total of 11 AF simulations and 12 AF patients are considered in the analysis. For each patient, intracardiac electrograms were acquired in 15 locations from both atria. The accuracy of both methods was assessed by calculating the absolute errors of the highest DFBSPM (HDFBSPM) with respect to the atrial HDF, either simulated or intracardially measured, and assumed correct if ¿1 Hz. The spatial distribution of the errors between torso DFs and atrial HDFs were compared with atria driving mechanism locations. Torso HDF regions, defined as portions of the maps with |DF ¿ HDFBSPM| ¿ 0.5 Hz were identified and the percentage of the torso occuping these regions was compared between methods. The robustness of both methods to white Gaussian noise, ventricular influence and harmonics, and to lower spatial resolution BSPM lead layouts was analyzed: computer AF models (567 leads vs 256 leads down to 16 leads) and patient data (67 leads vs 32 and 16 leads). Main results: The proposed method allowed an improvement in non-invasive estimation of the atria HDF. For the models the median relative errors were 7.14% for the wavelet-based algorithm vs 60.00% for the Welch method; in patients, the errors were 10.03% vs 12.66%, respectively. The wavelet method outperformed the Welch approach in correct estimations of atrial HDFs in models (81.82% vs 45.45%, respectively) and patients (66.67% vs 41.67%). A low positive BSPM-DF map correlation was seen between the techniques (0.47 for models and 0.63 for patients), highlighting the overall differences in DF distributions. The wavelet-based algorithm was more robust to white Gaussian noise, residual ventricular activity and harmonics, and presented more consistent results in lead layouts with low spatial resolution. Significance: Estimation of atrial HDFs using BSPM is improved by the proposed wavelet-based algorithm, helping to increase the non-invasive diagnostic ability in AF.This study was supported in part by grants from Sao Paulo Research Foundation (2017/19775-3), Instituto de Salud Carlos III FEDER (Fondo Europeo de Desarrollo Regional PI17/01106) and Generalitat Valenciana Grants (AICO/2018/267).Marques, V.; Rodrigo Bort, M.; Guillem Sánchez, MS.; Salinet, J. (2020). A robust wavelet-based approach for dominant frequency analysis of atrial fibrillation in body surface signals. Physiological Measurement. 41(7):1-14. https://doi.org/10.1088/1361-6579/ab97c1S11441

Patterns of genetic diversity and linkage disequilibrium in a highly structured Hordeum vulgare association-mapping population for the Mediterranean basin

Population structure and genome-wide linkage disequilibrium (LD) were investigated in 192 Hordeum vulgare accessions providing a comprehensive coverage of past and present barley breeding in the Mediterranean basin, using 50 nuclear microsatellite and 1,130 DArT® markers. Both clustering and principal coordinate analyses clearly sub-divided the sample into five distinct groups centred on key ancestors and regions of origin of the germplasm. For given genetic distances, large variation in LD values was observed, ranging from closely linked markers completely at equilibrium to marker pairs at 50 cM separation still showing significant LD. Mean LD values across the whole population sample decayed below r 2 of 0.15 after 3.2 cM. By assaying 1,130 genome-wide DArT® markers, we demonstrated that, after accounting for population substructure, current genome coverage of 1 marker per 1.5 cM except for chromosome 4H with 1 marker per 3.62 cM is sufficient for whole genome association scans. We show, by identifying associations with powdery mildew that map in genomic regions known to have resistance loci, that associations can be detected in strongly stratified samples provided population structure is effectively controlled in the analysis. The population we describe is, therefore, shown to be a valuable resource, which can be used in basic and applied research in barle

Systematic review and meta-analysis on certolizumab pegol for rheumatoid arthritis in adults

Background The appearance of tumor necrosis factor-alpha (TNFalpha) inhibitors dramatically changed the prognosis of rheumatoid arthritis. Certolizumab pegol (CZP) is a human Fab fragment of anti-TNFalpha monoclonal antibody which is approved for the treatment of rheumatoid arthritis. We performed a systematic review and meta-analysis, with Cochrane methodology, of the effects of CZP in rheumatoid arthritis. Objectives To assess the clinical benefits and harms of CZP in patients with rheumatoid arthritis. Methods We performed a search of electronic database (Cochrane Database, MEDLINE, EMBASE, Web of Knowledge and clinicaltrials.gov) until 26th September 2016. We searched for randomized controlled trials of CZP in rheumatoid arthritis compared to any other agent including placebo. Results 14 trials were included for the meta-analysis, 12 (5422 patients) in the pooled analysis for benefits and 14 (5499 patients) in the pooled analysis for safety. The overall possibility of bias seemed to be low but the quality of the evidence was low due to the risk of attrition bias. With the approved dose - CZP 200 mg subcutaneous every other week with the first three doses of 400 mg - CZP showed statistically significant improvements at 24 weeks compared to placebo in: ACR50 absolute improvement 27% (95% CI 20% to 33%), RR 3.8 (95% CI 2.42 to 5.95) and NNT=4 (95% CI 3 to 8); DAS28 <2.6 - original definition of remission - with RR 3.79 (95% CI 1.90 to 7.56); HAQ with -12% absolute improvement (95% CI -9% to -14%); and erosion score with -0.29% (95% CI -0.42% to -0.17%). There are also data available at 12 weeks with RR of 1.99 (95% CI 1.44 to 2.76) of achieving DAS28<2.6 with CZP 200 mg dose. The proportion of patients achieving DAS28<2.6 was still higher with CZP at 52 weeks with RR of 1.83 (95% CI 1.53 to 2.18). Serious adverse events were more frequent for CZP 200 mg dose with a RR of 1.47 (95% CI 1.13 to 1.91) and NNH of 32. There have been eight adverse events leading to death in CZP 200 mg group versus two in the control group (not statistically significant) and 10 patients developing tuberculosis versus two in the control group (not statistically significant). Conclusions There is low level evidence from randomized controlled trials that CZP as monotherapy or combined with methotrexate improved ACR50, DAS28, HAQ and joint damaged on x-ray. Adverse events were more frequent with active treatment

Certolizumab pegol (CDP870) for rheumatoid arthritis in adults

Background Tumour necrosis factor (TNF)-alpha inhibitors are beneficial for the treatment of rheumatoid arthritis (RA) for reducing the risk of joint damage, improving physical function and improving the quality of life. This review is an update of the 2014 Cochrane Review of the treatment of RA with certolizumab pegol. Objectives To assess the clinical benefits and harms of certolizumab pegol (CZP) in people with RA who have not responded well to conventional disease-modifying anti-rheumatic drugs (DMARDs). Search methods We searched the Cochrane Central Register of Controlled Trials (CENTRAL: Cochrane Library 2016, Issue 9), MEDLINE, Embase, Web of Knowledge, reference lists of articles, clinicaltrials.gov and ICTRP of WHO. The searches were updated from 2014 (date of the last search for the previous version) to 26 September 2016. Selection criteria Randomised controlled trials that compared certolizumab pegol with any other agent, including placebo or methotrexate (MTX), in adults with active RA, regardless of current or prior treatment with conventional disease-modifying anti-rheumatic drugs (DMARDs), such as MTX. Data collection and analysis Two review authors independently checked search results, extracted data and assessed trial quality. We resolved disagreements by discussion or referral to a third review author. Main results We included 14 trials in this update, three more than previously. Twelve trials (5422 participants) included measures of benefit. We pooled 11 of them, two more than previously. Thirteen trials included information on harms, (5273 participants). The duration of follow-up varied from 12 to 52 weeks and the range of doses of certolizumab pegol varied from 50 to 400 mg given subcutaneously. In Phase III trials, the comparator was placebo plus MTX in seven trials and placebo in five. In the two Phase II trials the comparator was only placebo. The approved dose of certolizumab pegol, 200 mg every other week, produced clinically important improvements at 24 weeks for the following outcomes: - American College of Rheumatology (ACR) 50% improvement (pain, function and other symptoms of RA): 25% absolute improvement (95% confidence interval (CI) 20% to 33%); number need to treat for an additional beneficial outcome (NNTB) of 4 (95% CI 3 to 5); risk ratio (RR) 3.80 (95% CI 2.42 to 5.95), 1445 participants, 5 studies. - The Health Assessment Questionnaire (HAQ): -12% absolute improvement (95% CI -9% to -14%); NNTB of 8 (95% CI 7 to 11); mean difference (MD) - 0.35 (95% CI -0.43 to -0.26; 1268 participants, 4 studies) (scale 0 to 3; lower scores mean better function). - Proportion of participants achieving remission (Disease Activity Score (DAS) < 2.6) absolute improvement 10% (95% CI 8% to 16%); NNTB of 8 (95% CI 6 to 12); risk ratio (RR) 2.94 (95% CI 1.64 to 5.28), 2420 participants, six studies. - Radiological changes: erosion score (ES) absolute improvement -0.29% (95% CI -0.42% to -0.17%); NNTB of 6 (95% CI 4 to 10); MD -0.67 (95% CI -0.96 to -0.38); 714 participants, two studies (scale 0 to 230), but not a clinically important difference. -Serious adverse events (SAEs) were statistically but not clinically significantly more frequent for certolizumab pegol (200 mg every other week) with an absolute rate difference of 3% (95% CI 1% to 4%); number needed to treat for an additional harmful outcome (NNTH) of 33 (95% CI 25 to 100); Peto odds ratio (OR) 1.47 (95% CI 1.13 to 1.91); 3927 participants, nine studies. There was a clinically significant increase in all withdrawals in the placebo groups (for all doses and at all follow-ups) with an absolute rate difference of -29% (95% CI -16% to -42%), NNTH of 3 (95% CI 2 to 6), RR 0.47 (95% CI 0.39 to 0.56); and there was a clinically significant increase in withdrawals due to adverse events in the certolizumab groups (for all doses and at all follow-ups) with an absolute rate difference of 2% (95% CI 0% to 3%); NNTH of 58 (95% CI 28 to 329); Peto OR 1.45 (95% CI 1.09 to 1.94) 5236 participants Twelve studies. We judged the quality of evidence to be high for ACR50, DAS remission, SAEs and withdrawals due to adverse events, and moderate for HAQ and radiological changes, due to concerns about attrition bias. For all withdrawals we judged the quality of evidence to be moderate, due to inconsistency. Authors' conclusions The results and conclusions did not change from the previous review. There is a moderate to high certainty of evidence from randomised controlled trials that certolizumab pegol, alone or combined with methotrexate, is beneficial in the treatment of RA for improved ACR50 and health-related quality of life, an increased chance of remission of RA, and reduced joint damage as seen on x-ray. Fewer people stopped taking their treatment, but most of these who did stopped due to serious adverse events. Adverse events were more frequent with active treatment. We found a clinically but not statistically significant risk of serious adverse events

Heparin versus 0.9% sodium chloride locking for prevention of occlusion in central venous catheters in adults

Background Intermittent locking of central venous catheters (CVCs) is undertaken to help maintain their patency. There are systematic variations in care: some practitioners use heparin (at different concentrations), whilst others use 0.9% NaCl (normal saline). This review looks at the effectiveness and safety of intermittent locking with heparin compared to 0.9% NaCl to see if the evidence establishes whether one is better than the other. This work is an update of a review first published in 2014. Objectives To assess the effectiveness and safety of intermittent locking of CVCs with heparin versus normal saline (NS) in adults to prevent occlusion. Search methods The Cochrane Vascular Information Specialist (CIS) searched the Specialised Register (last searched 11 June 2018) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 5). Searches were also carried out in MEDLINE, Embase, CINAHL, and clinical trials databases (11 June 2018). Selection criteria We included randomised controlled trials in adults ≥ 18 years of age with a CVC that compared intermittent locking with heparin at any concentration versus NS. We applied no restriction on language. Data collection and analysis Two review authors independently selected trials, assessed quality, and extracted data. We contacted trial authors to retrieve additional information, when necessary.We carried out statistical analysis using ReviewManager 5 and assessed the overall quality of the evidence supporting assessed outcomes using GRADE. We carried out prespecified subgroup analysis. Main results We identified five new studies for this update (six prior studies were included in the original review), bringing the number of eligible studies to 11, with a total of 2392 participants. We noted differences in methods used by the included studies and variation in heparin concentrations (10 to 5000 IU/mL), time to follow-up (1 to 251.8 days), and the unit of analysis used (participant, catheter, line access). Combined results fromthese studies showed fewer occlusions with heparin than with NS (risk ratio (RR) 0.70, 95%confidence interval (CI) 0.51 to 0.95; P = 0.02; 1672 participants; 1025 catheters from 10 studies; I² = 14%) and provided very low-quality evidence. We carried out subgroup analysis by unit of analysis (testing for subgroup differences (P = 0.23; I² = 30.3%). When the unit of analysis was the participant, results show no clear differences in all occlusions between heparin and NS (RR 0.79, 95% CI 0.58 to 1.08; P = 0.15; 1672 participants; seven studies). Subgroup analysis using the catheter as the unit of analysis shows fewer occlusions with heparin use (RR 0.53, 95% CI 0.29 to 0.95; P = 0.03; 1025 catheters; three studies). When the unit of analysis was line access, results show no clear differences in occlusions between heparin and NS (RR 1.08, 95% CI 0.84 to 1.40; 770 line accesses; one study). We found no clear differences in the duration of catheter patency (mean difference (MD) 0.44 days, 95% CI -0.10 to 0.99; P = 0.11; 1036 participants; 752 catheters; six studies; low-quality evidence). We found no clear evidence of a difference in the following: CVC-related sepsis (RR 0.74, 95% CI 0.03 to 19.54; P = 0.86; 1097 participants; two studies; low-quality evidence); mortality (RR 0.76, 95% CI 0.44 to 1.31; P = 0.33; 1100 participants; three studies; low-quality evidence); haemorrhage at any site (RR 1.32, 95% CI 0.57 to 3.07; P = 0.52; 1245 participants; four studies; moderatequality evidence); or heparin-induced thrombocytopaenia (RR 0.21, 95% CI 0.01 to 4.27; P = 0.31; 443 participants; three studies; low-quality evidence). Themain reasons for downgrading the quality of evidencewere unclear allocation concealment, imprecision, and suspicion of publication bias. Authors’ conclusions Given the very low quality of the evidence, we are uncertain whether intermittent locking with heparin results in fewer occlusions than intermittent locking with NS. Low-quality evidence suggests that heparin may have little or no effect on catheter patency. Although we found no evidence of differences in safety (sepsis, mortality, or haemorrhage), the combined trials are not powered to detect rare adverse events such as heparin-induced thrombocytopaenia

Mapping adaptation of barley to droughted environments

Identifying barley genomic regions influencing the response of yield and its components to water deficits will aid in our understanding of the genetics of drought tolerance and the development of more drought tolerant cultivars. We assembled a population of 192 genotypes that represented landraces, old, and contemporary cultivars sampling key regions around the Mediterranean basin and the rest of Europe. The population was genotyped with a stratified set of 50 genomic and EST derived molecular markers, 49 of which were Simple Sequence Repeats (SSRs), which revealed an underlying population sub-structure that corresponded closely to the geographic regions in which the genotypes were grown. A more dense whole genome scan was generated by using Diversity Array Technology (DArT®) to generate 1130 biallelic markers for the population. The population was grown at two contrasting sites in each of seven Mediterranean countries for harvest 2004 and 2005 and grain yield data collected. Mean yield levels ranged from 0.3 to 6.2 t/ha, with highly significant genetic variation in low-yielding environments. Associations of yield with barley genomic regions were then detected by combining the DArT marker data with the yield data in mixed model analyses for the individual trials, followed by multiple regression of yield on markers to identify a multi-locus subset of significant markers/QTLs. QTLs exhibiting a pre-defined consistency across environments were detected in bins 4, 6, 6 and 7 on barley chromosomes 3H, 4H, 5H and 7H respectivel