372 research outputs found

    Development and field evaluation of an online monitor for near-continuous measurement of iron, manganese, and chromium in coarse airborne particulate matter (PM)

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    A novel air sampling monitor was developed for near-continuous (i.e., 2-h time resolution) measurement of iron (Fe), manganese (Mn), and chromium (Cr) concentrations in ambient coarse particulate matter (PM) (i.e., PM10–2.5). The developed monitor consists of two modules: (1) the coarse PM collection module, utilizing two virtual impactors (VIs) connected to a modified BioSampler to collect ambient coarse PM into aqueous slurry samples; (2) the metal concentration measurement module, which quantifies the light absorption of colored complexes formed through the reactions between the soluble and solubilized target metals and pertinent analytical reagents in the collected slurries using a micro volume flow cell (MVFC) coupled with UV/VIS spectrophotometry. The developed monitor was deployed in the field for continuous ambient PM collection and measurements from January to April 2016 to evaluate its performance and reliability. Overall, the developed monitor could achieve accurate and reliable measurements of the trace metals Fe, Mn, and Cr over long sampling periods, based on the agreement between the metal concentrations measured via this online monitor and off-line parallel measurements obtained using filter samplers. Based on our results, it can be concluded that the developed monitor is a promising technology for near-continuous measurements of metal concentrations in ambient coarse PM. Moreover, this monitor can be readily configured to measure the speciation (i.e., water-soluble portion as well as specific oxidation states) of these metal species. These unique abilities are essential tools in investigations of sources and atmospheric processes influencing the concentrations of these redox-active metals in coarse PM. Copyright © 2016 American Association for Aerosol Research © 2016 American Association for Aerosol Research

    Namukwana (Lwembo Mu Lusoga)

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    The story is about a woman called Namukwana and her husband Ndooga who had six children & they were all girls. when the woman got pregnant she was promised a party if she gave birth to a baby boy or be divorced if it was a girl.The story is about a woman called Namukwana and her husband Ndooga who had six children & they were all girls. when the woman got pregnant she was promised a party if she gave birth to a baby boy or be divorced if it was a girl

    Efficient Data Reduction at the Edge of Industrial Internet of Things for PMSM Bearing Fault Diagnosis

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    An efficient data reduction algorithm is designed and implemented on an industrial Internet of Things (IIoT) node for permanent magnet synchronous motor (PMSM) bearing fault diagnosis in variable speed conditions. Leakage flux and vibration signals are respectively acquired by a magnetic sensor and an accelerometer on the IIoT node in a non-invasive manner. These two signals are processed and mixed on the IIoT and transmitted to a server. The received signal is separated, the cumulative rotation angle is calculated, and the vibration signal is resampled for bearing fault identification. The proposed method can reduce about 95% of the transmission data while maintaining sufficient precision in bearing fault diagnosis in comparison with a traditional method. The proposed method based on edge computing reduces the power consumption, and hence it is suitable to use on a battery-supplied IIoT node for remote PMSM condition monitoring and fault diagnosis

    Aortic microcalcification is associated with elastin fragmentation in Marfan syndrome

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    Marfan syndrome (MFS) is a connective tissue disorder in which aortic rupture is the major cause of death. MFS patients with an aortic diameter below the advised limit for prophylactic surgery (<5 cm) may unexpectedly experience an aortic dissection or rupture, despite yearly monitoring. Hence, there is a clear need for improved prognostic markers to predict such aortic events. We hypothesize that elastin fragments play a causal role in aortic calcification in MFS, and that microcalcification serves as a marker for aortic disease severity. To address this hypothesis, we analysed MFS patient and mouse aortas. MFS patient aortic tissue showed enhanced microcalcification in areas with extensive elastic lamina fragmentation in the media. A causal relationship between medial injury and microcalcification was revealed by studies in vascular smooth muscle cells (SMCs); elastin peptides were shown to increase the activity of the calcification marker alkaline phosphatase (ALP) and reduce the expression of the calcification inhibitor matrix GLA protein in human SMCs. In murine Fbn1C1039G/+ MFS aortic SMCs, Alpl mRNA and activity were upregulated as compared with wild-type SMCs. The elastin peptide-induced ALP activity was prevented by incubation with lactose or a neuraminidase inhibitor, which inhibit the elastin receptor complex, and a mitogen-activated protein kinase kinase-1/2 inhibitor, indicating downstream involvement of extracellular signal-regulated kinase-1/2 (ERK1/2) phosphorylation. Histological analyses in MFS mice revealed macrocalcification in the aortic root, whereas the ascending aorta contained microcalcification, as identified with the near-infrared fluorescent bisphosphonate probe OsteoSense-800. Significantly, microcalcification correlated strongly with aortic diameter, distensibility, elastin breaks, and phosphorylated ERK1/2. In conclusion, microcalcification co-localizes with aortic elastin degradation in MFS aortas of humans and mice, where elastin-derived peptides induce a calcification process in SMCs via the elastin receptor complex and ERK1/2 activation. We propose microcalcification as a novel imaging marker to monitor local elastin degradation a

    Tourism Destination Management: A Collaborative Approach

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    Collaboration is a key factor of sustainable growth across territories and industrial sectors. Tourism, one of the largest industries in the world, has been subject to strongest innovation in the last years. Main reasons of this reside both in the availability of new ICTs - Information and Communication Technologies - and organizational models, which directly connect tourists among them and with service providers, and in the always more personalized supply of tourism experience. Tourism destinations can benefit of such innovations if they are able to reorganize the territorial tourism offer around different pattern of collaboration in order to give 2.0 tourists opportunities to live an augmented tourism experience. This paper deals with the possible forms of collaborative networks that can rise within a destination with a focus on relationships between services delivered by the Tourism Destination and the requests of services at the different phases of the tourist 2.0 lifecycle

    Superfluidity and collective oscillations of trapped Bose-Einstein condensates in a periodical potential

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    Based on a unified theoretical treatment of the 1D Bogoliubov-de Genes equations, the superfluidity phenomenon of the Bose-Einstein condensates (BEC) loaded into trapped optical lattice is studied. Within the perturbation regime, an all-analytical framework is presented enabling a straightforward phenomenological mapping of the collective excitation and oscillation character of a trapped BEC where the available experimental configurations also fit.Comment: 5 pages and 2 Figs, some errors have been corrected in versions

    MIGHTEE-HI: The first MeerKAT HI mass function from an untargeted interferometric survey

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    We present the first measurement of the HI mass function (HIMF) using data from MeerKAT, based on 276 direct detections from the MIGHTEE Survey Early Science data covering a period of approximately a billion years (0z0.0840 \leq z \leq 0.084 ). This is the first HIMF measured using interferometric data over non-group or cluster field, i.e. a deep blank field. We constrain the parameters of the Schechter function which describes the HIMF with two different methods: 1/Vmax1/\rm V_{\rm max} and Modified Maximum Likelihood (MML). We find a low-mass slope α=1.290.26+0.37\alpha=-1.29^{+0.37}_{-0.26}, `knee' mass log10(M/M)=10.070.24+0.24\log_{10}(M_{*}/{\rm M_{\odot}}) = 10.07^{+0.24}_{-0.24} and normalisation log10(ϕ/Mpc3)=2.340.36+0.32\log_{10}(\phi_{*}/\rm Mpc^{-3})=-2.34^{+0.32}_{-0.36} (H0=67.4H_0 = 67.4 kms1^{-1} Mpc1^{-1}) for 1/Vmax1/\rm V_{\rm max} and α=1.440.10+0.13\alpha=-1.44^{+0.13}_{-0.10}, `knee' mass log10(M/M)=10.220.13+0.10\log_{10}(M_{*}/{\rm M_{\odot}}) = 10.22^{+0.10}_{-0.13} and normalisation log10(ϕ/Mpc3)=2.520.14+0.19\log_{10}(\phi_{*}/\rm Mpc^{-3})=-2.52^{+0.19}_{-0.14} for MML. When using 1/Vmax1/\rm V_{\rm max} we find both the low-mass slope and `knee' mass to be consistent within 1σ1\sigma with previous studies based on single-dish surveys. The cosmological mass density of HI is found to be slightly larger than previously reported: ΩHI=5.460.99+0.94×104h67.41\Omega_{\rm HI}=5.46^{+0.94}_{-0.99} \times 10^{-4}h^{-1}_{67.4} from 1/Vmax1/\rm V_{\rm max} and ΩHI=6.310.31+0.31×104h67.41\Omega_{\rm HI}=6.31^{+0.31}_{-0.31} \times 10^{-4}h^{-1}_{67.4} from MML but consistent within the uncertainties. We find no evidence for evolution of the HIMF over the last billion years.Comment: 13 pages, 9 figures, accepted for publication in MNRA

    Simultaneous analysis of free amino acids and biogenic amines in honey and wine samples using in loop orthophthalaldeyde derivatization procedure

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    This work presents a RP-HPLC method for the simultaneous quantification of free amino acids and biogenic amines in liquid food matrices and the results of the application to honey and wine samples obtained from different production processes and geographic origins. The developed methodology is based on a pre-column derivatization with o-phthaldialdehyde carried out in the sample injection loop. The compounds were separated in a Nova-Pack RP-C18 column (150 mm × 3.9 mm, 4 μm) at 35 °C. The mobile phase used was a mixture of phase A: 10 mM sodium phosphate buffer (pH 7.3), methanol and tetrahydrofuran (91:8:1); and phase B: methanol and phosphate buffer (80:20), with a flow rate of 1.0 ml/min. Fluorescence detection was used at an excitation wavelength of 335 nm and an emission wavelength of 440 nm. The separation and quantification of 19 amino acids and 6 amines was carried out in a single run as their OPA/MCE derivatives elute within 80 min, ensuring a reproducible quantification. The method showed to be adequate for the purpose, with an average RSD of 2% for the different amino acids; detection limits varying between 0.71 mg/l (Asn) and 8.26 mg/l (Lys) and recovery rates between 63.0% (Cad) and 98.0% (Asp). The amino acids present at the highest concentration in honey and wine samples were phenylalanine and arginine, respectively. Only residual levels of biogenic amines were detected in the analysed samples

    Study of e+eppˉe^+e^- \rightarrow p\bar{p} in the vicinity of ψ(3770)\psi(3770)

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    Using 2917 pb1\rm{pb}^{-1} of data accumulated at 3.773~GeV\rm{GeV}, 44.5~pb1\rm{pb}^{-1} of data accumulated at 3.65~GeV\rm{GeV} and data accumulated during a ψ(3770)\psi(3770) line-shape scan with the BESIII detector, the reaction e+eppˉe^+e^-\rightarrow p\bar{p} is studied considering a possible interference between resonant and continuum amplitudes. The cross section of e+eψ(3770)ppˉe^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}, σ(e+eψ(3770)ppˉ)\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}), is found to have two solutions, determined to be (0.059±0.032±0.0120.059\pm0.032\pm0.012) pb with the phase angle ϕ=(255.8±37.9±4.8)\phi = (255.8\pm37.9\pm4.8)^\circ (<<0.11 pb at the 90% confidence level), or σ(e+eψ(3770)ppˉ)=(2.57±0.12±0.12\sigma(e^+e^-\rightarrow\psi(3770)\rightarrow p\bar{p}) = (2.57\pm0.12\pm0.12) pb with ϕ=(266.9±6.1±0.9)\phi = (266.9\pm6.1\pm0.9)^\circ both of which agree with a destructive interference. Using the obtained cross section of ψ(3770)ppˉ\psi(3770)\rightarrow p\bar{p}, the cross section of ppˉψ(3770)p\bar{p}\rightarrow \psi(3770), which is useful information for the future PANDA experiment, is estimated to be either (9.8±5.79.8\pm5.7) nb (<17.2<17.2 nb at 90% C.L.) or (425.6±42.9)(425.6\pm42.9) nb
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