3,050 research outputs found

    Module production of the one-arm AFP 3D pixel tracker

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    The ATLAS Forward Proton (AFP) detector is designed to identify events in which one or two protons emerge intact from the LHC collisions. AFP will consist of a tracking detector, to measure the momentum of the protons, and a time of flight system to reduce the background from multiple proton-proton interactions. Following an extensive qualification period, 3D silicon pixel sensors were selected for the AFP tracker. The sensors were produced at CNM (Barcelona) during 2014. The tracker module assembly and quality control was performed at IFAE during 2015. The assembly of the first AFP arm and the following installation in the LHC tunnel took place in February 2016. This paper reviews the fabrication process of the AFP tracker focusing on the pixel modules.Comment: PIXEL 2016 proceedings; Submitted to JINS

    Fast determination of thiacloprid by photoinduced chemiluminescence

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    This paper was published in Applied Spectroscopy and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/as/abstract.cfm?URI=as-68-6-642. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.A new and sensitive application of the chemiluminescence detection has been developed for the determination of the pesticide thiacloprid in water. It was based on the on-line photoreaction of thiacloprid in basic medium, with quinine acting as sensitizer of the chemiluminescent response; Cerium (IV) in sulfuric acid medium was used as oxidant. A high automation and reproducibility was provided by a flow injection analysis (FIA) manifold. The validation of the method was performed in terms of selectivity, linearity, LOD, precision and accuracy. Liquid chromatography with UV detection was used as reference for mineral, tap, ground and spring water samples. The proposed method is fast (throughput of 130 h-1), sensitive (LOD of 0.8 ng mL-1 without preconcentration steps and 0.08 ng mL-1 with solid phase extraction (SPE)), low-cost and possible to couple with separative methods for the simultaneous determination of other pesticides. The enhanced chemiluminescence intensity was linear with thiacloprid concentration over the (2-80) and (80-800) ng mL-1 ranges. A possible reaction mechanism is also discussed.The authors thank the Ministerio de Educacion y Ciencia of Spain and the Fondo Europeo de Desarrollo Regional for financial support, Project CTM2006-11991.CatalĂĄ Icardo, M.; LĂłpez Paz, JL.; PĂ©rez Plancha, LM. (2014). Fast determination of thiacloprid by photoinduced chemiluminescence. Applied Spectroscopy. 68(6):642-648. https://doi.org/10.1366/13-07330S642648686Tomizawa, M., & Casida, J. E. (2005). NEONICOTINOID INSECTICIDE TOXICOLOGY: Mechanisms of Selective Action. Annual Review of Pharmacology and Toxicology, 45(1), 247-268. doi:10.1146/annurev.pharmtox.45.120403.095930Tapparo, A., Giorio, C., SoldĂ , L., Bogialli, S., Marton, D., Marzaro, M., & Girolami, V. (2012). UHPLC-DAD method for the determination of neonicotinoid insecticides in single bees and its relevance in honeybee colony loss investigations. Analytical and Bioanalytical Chemistry, 405(2-3), 1007-1014. doi:10.1007/s00216-012-6338-3Tennekes, H. A., & SĂĄnchez-Bayo, F. (2013). The molecular basis of simple relationships between exposure concentration and toxic effects with time. Toxicology, 309, 39-51. doi:10.1016/j.tox.2013.04.007Peña, A., RodrĂ­guez-LiĂ©bana, J. A., & Mingorance, M. D. (2011). Persistence of two neonicotinoid insecticides in wastewater, and in aqueous solutions of surfactants and dissolved organic matter. Chemosphere, 84(4), 464-470. doi:10.1016/j.chemosphere.2011.03.039Di Muccio, A., Fidente, P., Barbini, D. A., Dommarco, R., Seccia, S., & Morrica, P. (2006). Application of solid-phase extraction and liquid chromatography–mass spectrometry to the determination of neonicotinoid pesticide residues in fruit and vegetables. Journal of Chromatography A, 1108(1), 1-6. doi:10.1016/j.chroma.2005.12.111Fidente, P., Seccia, S., Vanni, F., & Morrica, P. (2005). Analysis of nicotinoid insecticides residues in honey by solid matrix partition clean-up and liquid chromatography–electrospray mass spectrometry. Journal of Chromatography A, 1094(1-2), 175-178. doi:10.1016/j.chroma.2005.09.012Seccia, S., Fidente, P., Barbini, D. A., & Morrica, P. (2005). Multiresidue determination of nicotinoid insecticide residues in drinking water by liquid chromatography with electrospray ionization mass spectrometry. Analytica Chimica Acta, 553(1-2), 21-26. doi:10.1016/j.aca.2005.08.006Pareja, L., MartĂ­nez-Bueno, M. J., Cesio, V., Heinzen, H., & FernĂĄndez-Alba, A. R. (2011). Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography–quadrupole-linear ion trap-mass spectrometry. Journal of Chromatography A, 1218(30), 4790-4798. doi:10.1016/j.chroma.2011.02.044Seccia, S., Fidente, P., Montesano, D., & Morrica, P. (2008). Determination of neonicotinoid insecticides residues in bovine milk samples by solid-phase extraction clean-up and liquid chromatography with diode-array detection. Journal of Chromatography A, 1214(1-2), 115-120. doi:10.1016/j.chroma.2008.10.088Wang, W., Li, Y., Wu, Q., Wang, C., Zang, X., & Wang, Z. (2012). Extraction of neonicotinoid insecticides from environmental water samples with magnetic graphene nanoparticles as adsorbent followed by determination with HPLC. Analytical Methods, 4(3), 766. doi:10.1039/c2ay05734dBi, X., & Yang, K.-L. (2009). On-Line Monitoring Imidacloprid and Thiacloprid in Celery Juice Using Quartz Crystal Microbalance. Analytical Chemistry, 81(2), 527-532. doi:10.1021/ac801786aGĂĄmiz-Gracia, L., Garcı́a-Campaña, A. M., Soto-Chinchilla, J. J., Huertas-PĂ©rez, J. F., & GonzĂĄlez-Casado, A. (2005). Analysis of pesticides by chemiluminescence detection in the liquid phase. TrAC Trends in Analytical Chemistry, 24(11), 927-942. doi:10.1016/j.trac.2005.05.009Roda, A., & Guardigli, M. (2011). Analytical chemiluminescence and bioluminescence: latest achievements and new horizons. Analytical and Bioanalytical Chemistry, 402(1), 69-76. doi:10.1007/s00216-011-5455-8Du, J., & Li, H. (2010). Sensitive Chemiluminescence Determination of Thirteen Cephalosporin Antibiotics with Luminol—Copper(II) Reaction. Applied Spectroscopy, 64(10), 1154-1159. doi:10.1366/000370210792973613Li, Y., Li, Y., & Yang, Y. (2011). Flow-Injection Chemiluminescence Determination of Lisinopril Using Luminol–KMnO4 Reaction Catalyzed by Silver Nanoparticles. Applied Spectroscopy, 65(4), 376-381. doi:10.1366/10-06115CatalĂĄ-Icardo, M., LĂłpez-Paz, J. L., Choves-BarĂłn, C., & Peña-BĂĄdena, A. (2012). Native vs photoinduced chemiluminescence in dimethoate determination. Analytica Chimica Acta, 710, 81-87. doi:10.1016/j.aca.2011.10.043Mestre, Y. F., Zamora, L. L., & Calatayud, J. M. (2001). Flow-chemiluminescence: a growing modality of pharmaceutical analysis. Luminescence, 16(3), 213-235. doi:10.1002/bio.608Lara, F. J., GarcĂ­a-Campaña, A. M., & Aaron, J.-J. (2010). Analytical applications of photoinduced chemiluminescence in flow systems—A review. Analytica Chimica Acta, 679(1-2), 17-30. doi:10.1016/j.aca.2010.09.001Icardo, M. C., & Calatayud, J. M. (2008). Photo-Induced Luminescence. Critical Reviews in Analytical Chemistry, 38(2), 118-130. doi:10.1080/10408340802039609RICART, I., ANTONFOS, G., DUART, M., MATEO, J., ZAMORA, L., & CALATAYUD, J. (2007). Theoretical prediction of the photoinduced chemiluminescence of pesticides. Talanta, 72(2), 378-386. doi:10.1016/j.talanta.2006.10.048Abramović, B. F., Banić, N. D., & Ć ojić, D. V. (2010). Degradation of thiacloprid in aqueous solution by UV and UV/H2O2 treatments. Chemosphere, 81(1), 114-119. doi:10.1016/j.chemosphere.2010.07.016Icardo, M. (2003). FI-on line photochemical reaction for direct chemiluminescence determination of photodegradated chloramphenicol. Talanta, 60(2-3), 405-414. doi:10.1016/s0039-9140(03)00074-2Zhao, Y., Baeyens, W. R. G., Zhang, X., Calokerinos, A. C., Nakashima, K., & Der Weken, G. V. (1997). Chemiluminescence Determination of Tiopronin by Flow Injection Analysis Based on Cerium(IV) Oxidation Sensitized by Quinine. The Analyst, 122(2), 103-106. doi:10.1039/a605703iZhang, Z., Baeyens, W. R. G., Zhang, X., Zhao, Y., & Van Der Weken, G. (1997). Chemiluminescence detection coupled to liquid chromatography for the determination of penicillamine in human urine. Analytica Chimica Acta, 347(3), 325-332. doi:10.1016/s0003-2670(97)00171-2CapitÃ¥n-Vallvey, L. (2000). Chemiluminescence determination of sodium 2-mercaptoethane sulfonate by flow injection analysis using cerium(IV) sensitized by quinine. Talanta, 51(6), 1155-1161. doi:10.1016/s0039-9140(00)00291-5NIE, L., MA, H., SUN, M., LI, X., SU, M., & LIANG, S. (2003). Direct chemiluminescence determination of cysteine in human serum using quinine–Ce(IV) system. Talanta, 59(5), 959-964. doi:10.1016/s0039-9140(02)00649-5Lakowicz, J. R. (Ed.). (2006). Principles of Fluorescence Spectroscopy. doi:10.1007/978-0-387-46312-4Lookabaugh, M., & Krull, I. S. (1988). Determination of nitrite and nitrate by reversed-phase high-performance liquid chromatography using on-line post-column photolysis with ultraviolet absorbance and electrochemical detection. Journal of Chromatography A, 452, 295-308. doi:10.1016/s0021-9673(01)81454-0GĂłmez-Benito, C., Meseguer-Lloret, S., & Torres-Cartas, S. (2013). Sensitive determination of Fenamiphos in water samples by flow injection photoinduced chemiluminescence. International Journal of Environmental Analytical Chemistry, 93(2), 152-165. doi:10.1080/03067319.2012.663755CATALÁ-ICARDO, M., LÓPEZ-PAZ, J. L., & PEÑA-BÁDENA, A. (2011). FI-photoinduced Chemiluminescence Method for Diuron Determination in Water Samples. Analytical Sciences, 27(3), 291. doi:10.2116/analsci.27.291Hamilton, D. J., Ambrus, Á., Dieterle, R. M., Felsot, A. S., Harris, C. A., Holland, P. T., 
 Wong, S.-S. (2003). Regulatory limits for pesticide residues in water (IUPAC Technical Report). Pure and Applied Chemistry, 75(8), 1123-1155. doi:10.1351/pac20037508112

    Polycyclic aromatic hydrocarbons in the dwarf galaxy IC 10

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    Infrared observations from the Spitzer Space Telescope archive are used to study the dust component of the interstellar medium in the IC~10 irregular galaxy. Dust distribution in the galaxy is compared to the distributions of Hα\alpha and [SII] emission, neutral hydrogen and CO clouds, and ionizing radiation sources. The distribution of polycyclic aromatic hydrocarbons (PAH) in the galaxy is shown to be highly non-uniform with the mass fraction of these particles in the total dust mass reaching 4%. PAHs tend to avoid bright HII regions and correlate well with atomic and molecular gas. This pattern suggests that PAHs form in the dense interstellar gas. We propose that the significant decrease of the PAH abundance at low metallicity is observed not only globally (at the level of entire galaxies), but also locally (at least, at the level of individual HII regions). We compare the distribution of the PAH mass fraction to the distribution of high-velocity features, that we have detected earlier in wings of Hα\alpha and SII lines, over the entire available galaxy area. No conclusive evidence for shock destruction of PAHs in the IC~10 galaxy could be found.Comment: Accepted for publication in Astronomy Report

    The role of large-scale spatial patterns in the chaotic amplification of perturbations in a Lorenz’96 model

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    The preparation of perturbed initial conditions to initialize an ensemble of numerical weather forecasts is a crucial task in current ensemble prediction systems (EPSs). Perturbations are added in the places where they are expected to grow faster, in order to provide an envelope of uncertainty along with the deterministic forecast. This work analyses the influence of large-scale spatial patterns on the growth of small perturbations. Therefore, we compare Lyapunov vector (LV) definitions, used in the initialization of state-of-the-art EPSs, with the so-called characteristic LVs. We test the dynamical behaviour of these LVs in the two-scale Lorenz’96 system. We find that the commonly used definitions of LVs include non-intrinsic and spurious effects due to their mutual orthogonality. We also find that the spatial locations where the small-scale perturbations are growing are ‘quantized’ by the large-scale pattern. This ‘quantization’ enhances the artificial disposition of the LVs, which is only avoided using the characteristic LVs, an unambiguous basis which may also be of great use in realistic models for assessing or initializing EPSs

    Mining for diagnostic information in body surface potential maps: A comparison of feature selection techniques

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    BACKGROUND: In body surface potential mapping, increased spatial sampling is used to allow more accurate detection of a cardiac abnormality. Although diagnostically superior to more conventional electrocardiographic techniques, the perceived complexity of the Body Surface Potential Map (BSPM) acquisition process has prohibited its acceptance in clinical practice. For this reason there is an interest in striking a compromise between the minimum number of electrocardiographic recording sites required to sample the maximum electrocardiographic information. METHODS: In the current study, several techniques widely used in the domains of data mining and knowledge discovery have been employed to mine for diagnostic information in 192 lead BSPMs. In particular, the Single Variable Classifier (SVC) based filter and Sequential Forward Selection (SFS) based wrapper approaches to feature selection have been implemented and evaluated. Using a set of recordings from 116 subjects, the diagnostic ability of subsets of 3, 6, 9, 12, 24 and 32 electrocardiographic recording sites have been evaluated based on their ability to correctly asses the presence or absence of Myocardial Infarction (MI). RESULTS: It was observed that the wrapper approach, using sequential forward selection and a 5 nearest neighbour classifier, was capable of choosing a set of 24 recording sites that could correctly classify 82.8% of BSPMs. Although the filter method performed slightly less favourably, the performance was comparable with a classification accuracy of 79.3%. In addition, experiments were conducted to show how (a) features chosen using the wrapper approach were specific to the classifier used in the selection model, and (b) lead subsets chosen were not necessarily unique. CONCLUSION: It was concluded that both the filter and wrapper approaches adopted were suitable for guiding the choice of recording sites useful for determining the presence of MI. It should be noted however that in this study recording sites have been suggested on their ability to detect disease and such sites may not be optimal for estimating body surface potential distributions

    CALIFA, the Calar Alto Legacy Integral Field Area survey: I. Survey presentation

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    We present here the Calar Alto Legacy Integral Field Area (CALIFA) survey, which has been designed to provide a first step in this direction.We summarize the survey goals and design, including sample selection and observational strategy.We also showcase the data taken during the first observing runs (June/July 2010) and outline the reduction pipeline, quality control schemes and general characteristics of the reduced data. This survey is obtaining spatially resolved spectroscopic information of a diameter selected sample of ∌600\sim600 galaxies in the Local Universe (0.005< z <0.03). CALIFA has been designed to allow the building of two-dimensional maps of the following quantities: (a) stellar populations: ages and metallicities; (b) ionized gas: distribution, excitation mechanism and chemical abundances; and (c) kinematic properties: both from stellar and ionized gas components. CALIFA uses the PPAK Integral Field Unit (IFU), with a hexagonal field-of-view of \sim1.3\sq\arcmin', with a 100% covering factor by adopting a three-pointing dithering scheme. The optical wavelength range is covered from 3700 to 7000 {\AA}, using two overlapping setups (V500 and V1200), with different resolutions: R\sim850 and R\sim1650, respectively. CALIFA is a legacy survey, intended for the community. The reduced data will be released, once the quality has been guaranteed. The analyzed data fulfill the expectations of the original observing proposal, on the basis of a set of quality checks and exploratory analysis. We conclude from this first look at the data that CALIFA will be an important resource for archaeological studies of galaxies in the Local Universe.Comment: 32 pages, 29 figures, Accepted for publishing in Astronomy and Astrophysic

    A novel thymidylate synthase from the Vibrionales, Alteromonadales, Aeromonadales, and Pasteurellales (VAAP) clade with altered nucleotide and folate binding sites

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    Thymidylate synthase (TS, E.C. 2.1.1.45) is a crucial enzyme for de novo deoxythymidine monophosphate (dTMP) biosynthesis. The gene for this enzyme is thyA, which encodes the folate-dependent TS that converts deoxyuridine monophosphate group (dUMP) into (dTMP) using the cofactor 5,10-methylenetetrahydrofolate (mTHF) as a carbon donor. We identified the thyA gene in the genome of the Vibrio parahaemolyticus strain FIM-S1708+ that is innocuous to humans but pathogenic to crustaceans. Surprisingly, we found changes in the residues that bind the substrate dUMP and mTHF, previously postulated as invariant among all TSs known (Finer-Moore, Santi & Stroud, 2003). Interestingly, those amino acid changes were also found in a clade of microorganisms that contains Vibrionales, Alteromonadales, Aeromonadales, and Pasteurellales (VAAP) from the Gammaproteobacteria class. In this work, we studied the biochemical properties of recombinant TS from V. parahemolyticus FIM-S1708+ (VpTS) to address the natural changes in the TS amino acid sequence of the VAAP clade. Interestingly, the Km for dUMP was 27.3 ± 4.3 ”M, about one-fold larger compared to other TSs. The Km for mTHF was 96.3 ± 18 ”M, about three- to five-fold larger compared to other species, suggesting also loss of affinity. Thus, the catalytic efficiency was between one or two orders of magnitude smaller for both substrates. We used trimethoprim, a common antibiotic that targets both TS and DHFR for inhibition studies. The IC50 values obtained were high compared to other results in the literature. Nonetheless, this molecule could be a lead for the design antibiotics towards pathogens from the VAAP clade. Overall, the experimental results also suggest that in the VAAP clade the nucleotide salvage pathway is important and should be investigated, since the de novo dTMP synthesis appears to be compromised by a less efficient thymidylate synthase

    Quantum entanglement and disentanglement of multi-atom systems

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    We present a review of recent research on quantum entanglement, with special emphasis on entanglement between single atoms, processing of an encoded entanglement and its temporary evolution. Analysis based on the density matrix formalism are described. We give a simple description of the entangling procedure and explore the role of the environment in creation of entanglement and in disentanglement of atomic systems. A particular process we will focus on is spontaneous emission, usually recognized as an irreversible loss of information and entanglement encoded in the internal states of the system. We illustrate some certain circumstances where this irreversible process can in fact induce entanglement between separated systems. We also show how spontaneous emission reveals a competition between the Bell states of a two qubit system that leads to the recently discovered "sudden" features in the temporal evolution of entanglement. An another problem illustrated in details is a deterministic preparation of atoms and atomic ensembles in long-lived stationary squeezed states and entangled cluster states. We then determine how to trigger the evolution of the stable entanglement and also address the issue of a steered evolution of entanglement between desired pairs of qubits that can be achieved simply by varying the parameters of a given system.Comment: Review articl

    Freshwater microcrustaceans (Cladocera: Anomopoda and Ctenopoda, Copepoda: Cyclopoida and Calanoida) in the highly urbanized Metropolitan Manila area (Luzon, Philippines)

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    Despite the increasing interest in studying Cladocera and Copepoda in Philippine freshwaters, there is a need to update our knowledge on its taxonomy and distribution in highly urbanized areas, such as Metropolitan Manila. This paper presents an updated listing of freshwater microcrustaceans and their distribution in Metropolitan Manila, considering the continued deterioration of water quality and increased urbanization in many areas since the last comprehensive study on these taxa in 1950s. We collected water samples from 33 freshwater sites in Metropolitan Manila and 23 of which were found to contain microcrustacean zooplankton. A total of 13 species were identified including two new locality records for C. cornuta and D. dubium in Pasig River. All 8 cladocerans, we identified have already recorded in previous studies while 3 cyclopoid copepods are new records for Metropolitan Manila. Furthermore, 16% of all known freshwater microcrustacean zooplankton species in the Philippines are found in Metropolitan Manila, including the Luzon-endemic Filipinodiaptomus insulanus collected from man-made reservoirs in less-disturbed habitats (an urban wildlife park, golf course and eco-park). Other identified species such as Thermocyclops taihokuensis may serve as indicator for high levels of nutrient. These results point to the importance of monitoring urban aquatic biodiversity for their potential in determining aquatic ecosystem health and of maintaining urban aquatic sanctuaries which may serve as alternative habitat for flora and fauna in rapidly developing urban centers such as Metropolitan Manila

    Search for direct stau production in events with two hadronic tau-leptons in root s=13 TeV pp collisions with the ATLAS detector

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    A search for the direct production of the supersymmetric partners ofτ-leptons (staus) in final stateswith two hadronically decayingτ-leptons is presented. The analysis uses a dataset of pp collisions corresponding to an integrated luminosity of139fb−1, recorded with the ATLAS detector at the LargeHadron Collider at a center-of-mass energy of 13 TeV. No significant deviation from the expected StandardModel background is observed. Limits are derived in scenarios of direct production of stau pairs with eachstau decaying into the stable lightest neutralino and oneτ-lepton in simplified models where the two staumass eigenstates are degenerate. Stau masses from 120 GeV to 390 GeV are excluded at 95% confidencelevel for a massless lightest neutralino
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