4,245 research outputs found
Review of the measurements of the strong coupling constant at LEP 2
Since 1995, LEP has steadily increased the center of mass energy of the
colliding beams, from the M_Z resonance to 133, 161 and 172 GeV. New
measurements of the strong coupling constant, alpha_s, at these energies have
been performed by the LEP experiments, L3, ALEPH, OPAL and DELPHI. In this
article, the new results are summarized, and combined with the previous LEP
measurement of alpha_s(M_Z) in order to obtain an updated LEP average of
alpha_s(M_Z) = 0.120 +- 0.005.Comment: 5-6 pages, 3 figures. Talk given at the DIS 97 conference, Chicago,
April 1997.Replacement: update figure 1. Also available here
http://hep.ph.liv.ac.uk/~martis
The ATLAS Tracker Upgrade: Short Strips Detectors for the sLHC
It is foreseen to increase the luminosity of the Large Hadron Collider (LHC) at CERN around 2018 by about an order of magnitude, with the upgraded machine dubbed Super-LHC or sLHC. The ATLAS experiment will require a new tracker for SLHC operation. In order to cope with the order of magnitude increase in pile-up backgrounds at the higher luminosity, an all silicon detector is being designed. The new strip detector will use significantly shorter strips than the current SCT in order to minimise the occupancy. As the increased luminosity will mean a corresponding increase in radiation dose, a new generation of extremely radiation hard silicon detectors is required. A massive R&D programme is underway to develop silicon sensors with sufficient radiation hardness. New front-end electronics and readout systems are being designed to cope with the higher data rates. The challenges of powering and cooling a very large strip detector will be discussed. Ideas on possible schemes for the layout and support mechanics will be shown. A key issue for the upgrade is the development of silicon sensors with sufficient radiation hardness for the pixel and strip layers. We have developed planar detectors to be made on p-type wafers in a number of different designs. These prototype detectors were then produced by a leading manufacturer and irradiated to a set of fluences matched to sLHC expections. The irradiated sensors were subsequently tested wit h LHC-readout-electronics in order to study the radiation-induced degradation, and determine their performance after serious hadron irradiation of up to 1015 Neutron-equivalent. The signal suffers degradation as a function of irradiation. It is however evident that sufficient charge can still be recorded even at the highest fluence. We will give an overview of the ATLAS tracker upgrade, in particular focusing on innermost silicon strip layers. Results from a wide range of irradiated silicon detectors will be presented. We will draw conclusions on what type and design of strip detectors to employ for the upgrades of the tracking layers in the sLHC upgrades of LHC experiments
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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
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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
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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
An ALMA Early Science survey of molecular absorption lines toward PKS1830-211 -- Analysis of the absorption profiles
We present the first results of an ALMA spectral survey of strong absorption
lines for common interstellar species in the z=0.89 molecular absorber toward
the lensed blazar PKS1830-211. The dataset brings essential information on the
structure and composition of the absorbing gas in the foreground galaxy. In
particular, we find absorption over large velocity intervals (gtrsim 100 km/s)
toward both lensed images of the blazar. This suggests either that the galaxy
inclination is intermediate and that we sample velocity gradients or streaming
motions in the disk plane, that the molecular gas has a large vertical
distribution or extraplanar components, or that the absorber is not a simple
spiral galaxy but might be a merger system. The number of detected species is
now reaching a total of 42 different species plus 14 different rare
isotopologues toward the SW image, and 14 species toward the NE line-of-sight.
The abundances of CH, H2O, HCO+, HCN, and NH3 relative to H2 are found to be
comparable to those in the Galactic diffuse medium. Of all the lines detected
so far toward PKS1830-211, the ground-state line of ortho-water has the deepest
absorption. We argue that ground-state lines of water have the best potential
for detecting diffuse molecular gas in absorption at high redshift.Comment: Accepted for publication in A&
Concepts and methods in studies measuring individual ethnobotanical knowledge
We review 34 quantitative studies that have measured individuallevel variations in ethnobotanical knowledge, analyzing how those studies have conceptualized and operationalized ethnobotanical knowledge. We found that this type of research is recent but growing, and is concentrated in indigenous peoples of developing countries. We also found that studies differ on how they conceptualize and measure individual ethnobotanical knowledge. As it is the case in other interdisciplinary research, the lack of conceptual consistency and comparable data limit the inferences that can be drawn from empirical analyses of ethnobotanical knowledge. Future research should 1) validate the consistency of measures of individual ethnobotanical knowledge; 2) analyze the reliability of data generated by the different methods developed so far; and 3) address the relationship between the various dimensions of ethnobotanical knowledge. Studies of individual ethnobotanical knowledge have the potential to contribute to a systematic understanding of humanity’s most widespread and ancient form of knowledge
The serenity of the meditating mind: A cross-cultural psychometric study on a two-factor higher order structure of mindfulness, its effects, and mechanisms related to mental health among experienced meditators.
Objective To investigate the psychometric and structural properties of the Five Facets Mindfulness Questionnaire (FFMQ) among meditators, to develop a short form, and to examine associations of mindfulness with mental health and the mechanisms of mindfulness. Methods Two independent samples were used, a German (n = 891) and a Spanish (n = 393) meditator sample, practicing various meditation styles. Structural and psychometric properties of the FFMQ were investigated with multigroup confirmatory factor analysis and exploratory structural equation modeling. Associations with mental health and mechanisms of mindfulness were examined with path analysis. Results The derived short form broadly matched a previous item selection in samples of non-meditators. Self-regulated Attention and Orientation to Experience governed the facets of mindfulness on a higher-order level. Higher-order factors of mindfulness and meditation experience were negatively associated with symptoms of depression and anxiety, and perceived stress. Decentering and nonattachment were the most salient mechanisms of mindfulness. Aspects of emotion regulation, bodily awareness, and nonattachment explained the effects of mindfulness on depression and anxiety. Conclusions A two-component conceptualization for the FFMQ, and for the study of mindfulness as a psychological construct, is recommended for future research. Mechanisms of mindfulness need to be examined in intervention studies
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