39 research outputs found

    First Results from the Arcminute Cosmology Bolometer Array Receiver

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    We review the first science results from the Arcminute Cosmology Bolometer Array Receiver (ACBAR); a multifrequency millimeter-wave receiver optimized for observations of the Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich (SZ) effect in clusters of galaxies. ACBAR was installed on the 2 m Viper telescope at the South Pole in January 2001 and the results presented here incorporate data through July 2002. We present the power spectrum of the CMB at 150 GHz over the range \ell = 150 - 3000 measured by ACBAR as well as estimates for the values of the cosmological parameters within the context of Lambda-CDM models. We find that the inclusion of Omega_Lambda greatly improves the fit to the power spectrum. We also observe a slight excess of small-scale anisotropy at 150 GHz; if interpreted as power from the SZ effect of unresolved clusters, the measured signal is consistent with CBI and BIMA within the context of the SZ power spectrum models tested.Comment: To be published in the proceedings of "The Cosmic Microwave Background and its Polarization", New Astronomy Reviews, (eds. S. Hanany and K.A. Olive). 10 pages, 2 figure

    The differential diagnosis of chronic daily headaches: an algorithm-based approach

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    Chronic daily headaches (CDHs) refers to primary headaches that happen on at least 15 days per month, for 4 or more hours per day, for at least three consecutive months. The differential diagnosis of CDHs is challenging and should proceed in an orderly fashion. The approach begins with a search for “red flags” that suggest the possibility of a secondary headache. If secondary headaches that mimic CDHs are excluded, either on clinical grounds or through investigation, the next step is to classify the headaches based on the duration of attacks. If the attacks last less than 4 hours per day, a trigeminal autonomic cephalalgia (TAC) is likely. TACs include episodic and chronic cluster headache, episodic and chronic paroxysmal hemicrania, SUNCT, and hypnic headache. If the duration is ≥4 h, a CDH is likely and the differential diagnosis encompasses chronic migraine, chronic tension-type headache, new daily persistent headache and hemicrania continua. The clinical approach to diagnosing CDH is the scope of this review

    Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.

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    BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362

    ATLAS detector and physics performance: Technical Design Report, 1

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    Radiometric Phase Correction

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    We analyze the technique of using radiometers to measure the precipitable water vapor (PWV) content of the atmosphere in order to correct interferometric data for phase noise due PWV fluctuations in the troposphere. We present an idealized model of phase fluctuations due to PWV variations in the troposphere based on the Taylor hypothesis, and we summarize the radiometry equations. We then consider various options for radiometric phase corrections, including: (i) the very demanding technique of making an absolute measurement of PWV at each antenna assuming an accurate (absolutely calibrated) measurement of brightness temperature, TB , and using a theoretical model for the troposphere and measured physical parameters for the troposphere (temperature, pressure, etc...), and (ii) the less demanding technique of using a strong celestial calibration source to derive an empirical relationship between brightness temperature fluctuations and atmospheric phase fluctuations. Radiometric phase cor..

    Co-culture of Clostridium beijerinckii L9, Clostridium butyricum M1 and Bacillus thermoamylovorans B5 for converting yeast waste into hydrogen

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    In order to enhance anaerobic hydrogen production from yeast waste, a series of 120-mL batch co-cultures of Clostridium beijerinckii L9, Clostridium butyricum M1, and Bacillus thermoamylovorans B5 under mesophilic conditions were established according to full factorial design (FFD) and mixture design (MD). The experimental results were subjected to multivariate and response surface analyses to determine the relationships between bacteria converting yeast waste into hydrogen. The results indicated clearly that C. beijerinckii L9 and C. butyricum M1 had significant potential to convert yeast waste into hydrogen. There was no significant hydrogen generation when B. thermoamylovorancs B5 alone was cultured with yeast waste. However, B. thermoamylovorancs B5 could significantly shorten the co-culture's hydrogen-producing lag phase. Response surface analyses demonstrate that B. thermoamylovorancs B5 can stimulate the specific hydrogen production rate of C. beijerinckii L9 and C. butyricum M1, greater in the case of the former than of the latter. An ultimate hydrogen yield of 46 mL H-2/g COD added yeast waste was obtained with an optimal volumetric ratio C. beijerinckii L9: C. butyricum M1: B. thermoamylovoranc B5 of 8.9:4.8:10.3. Highly reproducible co-culture results confirm that FFD and MD, via response surface analysis, are applicable to assess the roles of the individual microorganisms in the defined co-culture. Crown Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

    Biohydrogen production from soluble condensed molasses fermentation using anaerobic fermentation

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    Using anaerobic micro-organisms to convert organic waste to produce hydrogen gas gives the benefits of energy recovery and environmental protection. The objective of this study was to develop a biohydrogen production technology from food wastewater focusing on hydrogen production efficiency and micro-flora community at different hydraulic retention times. Soluble condensed molasses fermentation (CMS) was used as the substrate because it is sacchariferous and ideal for hydrogen production. CMS contains nutrient components that are necessary for bacterial growth: microbial protein, amino acids, organic acids, vitamins and coenzymes. The seed sludge was obtained from the waste activated sludge from a municipal sewage treatment plant in Central Taiwan. This seed sludge was rich in Clostridium sp. A CSTR (continuously stirred tank reactor) lab-scale hydrogen fermentor (working volume, 4.0 L) was operated at a hydraulic retention time (HRT) of 3-24 h with an influent CMS concentration of 40 g COD/L. The results showed that the peak hydrogen production rate of 390 mmol H(2)/L-d occurred at an organic loading rate (OLR) of 320 g COD/L-d at a HRT of 3 h. The peak hydrogen yield was obtained at an OLR of 80 g COD/L-d at a HRT of 12 h. At HRT 8 h, all hydrogenase mRNA detected were from Clostridium acetobutylicum-like and Clostridium pasteurianum-like hydrogen-producing bacteria by RT-PCR analysis. RNA based hydrogenase gene and 16S rRNA gene analysis suggests that Clostridium exists in the fermentative hydrogen-producing system and might be the dominant hydrogen-producing bacteria at tested HRTs (except 3 h). The hydrogen production feedstock from CMS is lower than that of sucrose and starch because CMS is a waste and has zero cost, requiring no added nutrients. Therefore, producing hydrogen from food wastewater is a more commercially feasible bioprocess. Crown Copyright (C) 2009 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu. All rights reserved

    Multi-scale 3D imaging of absorbing porous materials for solid oxide fuel cells.

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    International audienceThe performance of advanced functional materials for fuel cell applications are closely linked to the material composition and morphology at the micro and nano-scales. 3D characterization techniques that can provide bulk information at these fine scales are therefore essential for microstructure optimization of these materials. Here, the X-ray nano-holotomography technique is used to image various multi-phase and absorbing solid oxide fuel cell electrodes. Different porous structures for typical commercial cells and innovative electrode designs obtained using a freeze-casting process are studied. Taking advantage of the geometrical setup and the use of high energy X-rays, both large reconstructions (field of view: 150 A mu m) and local tomography at higher resolution (field of view: 50 A mu m) can be performed on the same sample to have a multi-scale approach. This produces highly representative sample volumes with a size/resolution ratio that allows the geometric and physical properties of the materials to be calculated, e.g., connectivity of each phase, mean particles diameters, specific surface area, particle size distributions, tortuosity factors, and densities of triple boundary lengths
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