692 research outputs found

    Psychological and socio-demographic variables associated with sexual risk behavior for sexually transmitted infections/HIV

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    New diagnoses of sexually transmitted infections (STIs) and HIV are rising in the adult population. The main objective of this study was to analyze whether knowledge of STIs/HIV, worry about STIs/HIV and pregnancy, and self-efficacy to refuse sex are predictors of sexual risk behaviors among Spanish young and adults. The study sample was composed of 1,106 young and adults of both sexes aged between 17 and 55 years. Results showed that being single, homosexual, having been tested for HIV, having previously contracted an STI, having a college education and earning a monthly income of €900 or more were the characteristics associated with higher scores in knowledge of STIs/HIV. Self-efficacy to refuse sex predicted most vaginal and anal sexual behaviors (i.e., age at vaginal and anal sex initiation and the number of couples that have remained vaginal sex). We also found that participants with greater knowledge of STIs/HIV reported older age at vaginal sex initiation and higher condom use in the first vaginal sexual contact. We consider that these findings can be useful for the development of STI/HIV prevention programs.La población adulta es un grupo ascendente en los nuevos diagnósticos de las infec de transmisión sexual (ITS) y el VIH. El objetivo principal es analizar si el conocimiento sobre el ITS/VIH, la preocupación por las ITS/VIH y el embarazo y la autoeficacia para rechazar relaciones sexuales son predictoras de las conductas sexuales de riesgo en jóvenes y adultos españoles. Participaron 1.106 jóvenes y adultos de ambos sexos, entre los 17 y los 55 años. Los resultados mostraron que ser soltero, homosexual, haberse hecho la prueba del VIH, haber tenido una ITS, tener estudios universitarios e ingresos económicos mensuales de 900 a más de 1.200 euros tenían las puntuaciones más altas en el conocimiento sobre el ITS/VIH. La autoeficacia predijo gran parte de las conductas sexuales vaginales y anales (la edad de inicio del sexo vaginal y anal y el número de parejas con las que se ha mantenido sexo vaginal). Además, se halló que a mayor conocimiento sobre ITS/VIH, mayor edad de inicio del sexo vaginal y mayor uso del preservativo en la primera relación sexual vaginal. Se espera que estos resultados sean útiles para el desarrollo de programas de prevención de ITS/VIH

    The accumulation of UV screen photoprotectors (mycosporine-like amino acids) in red macroalgae is influenced by nitrogen availability

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    Red macroalgae produce UV screen photoprotectors (Mycosporine like amino acids, MAAs) in response to increased UV radiation. They are low-molecular weight water-soluble nitrogen enriched molecules, absorbing UV radiation in the wavelength range 310-365 nm due to their cyclohexenone or cyclohexenimine chromophores. MAAs were quantified by means of high performance liquid chromatography (HPLC). The photoprotection capacity in the macroalgae has been inferred by their accumulation under increased UV radiation (spatial and temporal changes), by the correlation with reduced photoinhibition and decreased photodamage and by the increase of antioxidant activity in the cells. Despite the fact MAAs are nitrogen compounds, only few studies on nitrogen enrichment have been conducted. In this study, the influence of inorganic nitrogen on the accumulation of MAAs both under artificial and solar UVR in several macroalgae is presented . Both MAAs and biliproteins contents of several species increased in ammonium enriched seawater. Algae with high internal N content presented a higher photoprotection capacity, estimated as in vivo chlorophyll fluorescence parameters, than those growing under N depletion conditions. The relative composition of MAAs changed both under high irradiance and blue light, increasing the content of palythine and asterina-330 in relation to porphyra-334 and shinorine. In bifactorial experiments of UVR and nitrate, a positive synergic response of both variables on the production of MAAs was found. MAA content also increased under ammonium enrichment, obtained from fishpond effluents. The highest MAA-productivity was observed in outdoor-grown algae, indicating a positive effect of increased PAR and UVR on MAA accumulation. In conclusion, the accumulation of MAAs is favoured by inorganic nitrogen enrichment in the presence of UVR. MAAs can protect the algae against increased UV radiation through a double function: (1) UV screen capacity in both UVA and UVB radiation and (2) Antioxidant capacity of both oxo- and imino-MAAs. The use of MAAs as photoprotective sunscreens in cosmetic products is discussed.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

    Biomass-modulated fire dynamics during the last glacial-interglacial transition at the central pyrenees (Spain)

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    Understanding long-term fire ecology is essential for current day interpretation of ecosystem fire responses. However palaeoecology of fire is still poorly understood, especially at high-altitude mountain environments, despite the fact that these are fire-sensitive ecosystems and their resilience might be affected by changing fire regimes. We reconstruct wildfire occurrence since the Lateglacial (14.7. cal. ka BP) to the Mid-Holocene (6. cal. ka BP) and investigate the climate-fuel-fire relationships in a sedimentary sequence located at the treeline in the Central Spanish Pyrenees. Pollen, macro- and micro-charcoal were analysed for the identification of fire events (FE) in order to detect vegetation post-fire response and to define biomass-fire interactions. mean fire intervals (mfi) reduced since the Lateglacial, peaking at 9-7.7. cal. ka BP while from 7.7 to 6. cal. ka BP no fire is recorded. We hypothesise that Early Holocene maximum summer insolation, as climate forcing, and mesophyte forest expansion, as a fuel-creating factor, were responsible for accelerating fire occurrence in the Central Pyrenees treeline. We also found that fire had long-lasting negative effects on most of the treeline plant communities and that forest contraction from 7.7. cal. ka BP is likely linked to the ecosystem's threshold response to high fire frequencies.This research has been funded by the projects DINAMO (CGL2009-07992) (funding EGPF — grant ref. BES-2010-038593 and MSC), DINAMO2 (CGL2012-33063), ARAFIRE (2012 GA LC 064), GRACCIE-CONSOLIDER (CSD2007-00067). GGR was funded by the Juan de la Cierva Program (grant ref. JCI2009-04345) and JAE-Doc CSIC Program, LLM was supported by a postdoctoral MINT fellowship funded by the Institute for the Environment (Brunel University), AMC is a Ramón y Cajal fellow (ref: RYC-2008-02431), APS holds a grant funded by the Aragon Government (ref. 17030G/5423/480072/14003) and JAE holds a grant funded by the Basque Country Government (BFI-2010-5)

    What determines growth potential and juvenile quality of farmed fish species?

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    Enhanced production of high quality and healthy fry is a key target for a successful and competitive expansion of the aquaculture industry. Although large quantities of fish larvae are produced, survival rates are often low or highly variable and growth potential is in most cases not fully exploited, indicating significant gaps in our knowledge concerning optimal nutritional and culture conditions. Understanding the mechanisms that control early development and muscle growth are critical for the identification of time windows in development that introduce growth variation, and improve the viability and quality of juveniles. This literature review of the current state of knowledge aims to provide a framework for a better understanding of fish skeletal muscle ontogeny, and its impact on larval and juvenile quality as broadly defined. It focuses on fundamental biological knowledge relevant to larval phenotype and quality and, in particular, on the factors affecting the development of skeletal muscle. It also discusses the available methodologies to assess growth and larvae/juvenile quality, identifies gaps in knowledge and suggests future research directions. The focus is primarily on the major farmed non-salmonid fish species in Europe that include gilthead sea bream, European sea bass, turbot, Atlantic cod, Senegalese sole and Atlantic halibut

    Radar on RAIA: High frequency radars in the RAIA Observatory

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    The RADAR ON RAIA project aims to update and extend beyond the Galician border the High Frequency (HF) radar network that has been operating since 2011 in the framework of the RAIA Observatory. The Project is allowing the establishment of a cross-border collaboration beyond the physical infrastructure itself, developing a sharing strategy of maintenance procedures, validation and data processing on both sides of the border, as well as an easy and public access to all the information. In addition, new products are being developed to exploit the potential of the HF radar technology.Peer Reviewe

    Effect of Ultrasonic-Assisted Blanching on Size Variation, Heat Transfer, and Quality Parameters of Mushrooms

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    The main aim of this work was to assess the influence of the application of power ultrasound during blanching of mushrooms (60 90 °C) on the shrinkage, heat transfer, and quality parameters. Kinetics of mushroom shrinkage was modeled and coupled to a heat transfer model for conventional (CB) and ultrasonic-assisted blanching (UB). Cooking value and the integrated residual enzymatic activity were obtained through predicted temperatures and related to the hardness and color variations of mushrooms, respectively. The application of ultrasound led to an increase of shrinkage and heat transfer rates, being this increase more intense at low process temperatures. Consequently, processing time was decreased (30.7 46.0 %) and a reduction in hardness (25.2 40.8 %) and lightness (13.8 16.8 %) losses were obtained. The best retention of hardness was obtained by the UB at 60 °C, while to maintain the lightness it was the CB and UB at 90 °C. For enhancing both quality parameters simultaneously, a combined treatment (CT), which consisted of a CB 0.5 min at 90 °C and then an UB 19.9min at 60 °C, was designed. In this manner, compared with the conventional treatment at 60 °C, reductions of 39.1, 27.2, and 65.5 % for the process time, hardness and lightness losses were achieved, respectively. These results suggest that the CT could be considered as an interesting alternative to CB in order to reduce the processing time and improve the overall quality of blanched mushrooms.The authors acknowledge the financial support of Consejo Nacional de Investigaciones Cientificas y Tecnicas and Universidad Nacional de La Plata from Argentina, Erasmus Mundus Action 2-Strand 1 and EuroTango II Researcher Training Program and Ministerio de Economia y Competitividad (SPAIN) and the FEDER (project DPI2012-37466-CO3-03).Lespinard, A.; Bon Corbín, J.; Cárcel Carrión, JA.; Benedito Fort, JJ.; Mascheroni, RH. (2015). Effect of Ultrasonic-Assisted Blanching on Size Variation, Heat Transfer, and Quality Parameters of Mushrooms. Food and Bioprocess Technology. 8(1):41-53. https://doi.org/10.1007/s11947-014-1373-zS415381Aguirre, L., Frias, J. M., Barry-Ryan, C., & Grogan, H. (2009). Modelling browning and brown spotting of mushrooms (Agaricus bisporus) stored in controlled environmental conditions using image analysis. Journal of Food Engineering, 91, 280–286.Anantheswaran, R. C., Sastry, S. K., Beelman, R. B., Okereke, A., & Konanayakam, M. (1986). Effect of processing on yield, color, and texture of canned mushrooms. Journal of Food Science, 51(5), 1197–1200.Biekman, E. S. A., Kroese-Hoedeman, H. I., & Schijvens, E. P. H. M. (1996). Loss of solutes during blanching of mushrooms (Agaricus bisporus) as a result of shrinkage and extraction. Journal of Food Engineering, 28(2), 139–152.Biekman, E. S. A., van Remmen, H. H. J., Kroese-Hoedeman, H. I., Ogink, J. J. M., & Schijvens, E. P. H. M. (1997). Effect of shrinkage on the temperature increase in evacuated mushrooms (Agaricus bisporus) during blanching. Journal of Food Engineering, 33(1–2), 87–99.Brennan, M., Le Port, G., & Gormley, R. (2000). Post-harvest treatment with citric acid or hydrogen peroxide to extend the shelf life of fresh sliced mushrooms. Lebensmittel Wissenschaft und Technologie, 33, 285–289.Cárcel, J. A., Benedito, J., Rosselló, C., & Mulet, A. (2007). Influence of ultrasound intensity on mass transfer in apple immersed in a sucrose solution. Journal of Food Engineering, 78, 472–479.Cárcel, J. A., Benedito, J., Bon, J., & Mulet, A. (2007). High intensity ultrasound effects on meat brining. Meat Science, 76, 611–619.Cárcel, J. A., García-Pérez, J. V., Benedito, J., & Mulet, A. (2011). Food process innovation through new technologies: Use of ultrasound. Journal of Food Engineering, 110, 200–207.Cheng, X., Zhang, M., & Adhikari, B. (2013). The inactivation kinetics of polyphenol oxidase in mushroom (Agaricus bisporus) during thermal and thermosonic treatmemts. Ultrasonics Sonochemistry, 20, 674–679.Cliffe-Byrnes, V., & O’Beirne, D. (2007). Effects of gas atmosphere and temperature on the respiration rates of whole and sliced mushrooms (Agaricus bisporus): implications for film permeability in modified atmosphere packages. Journal of Food Science, 72, 197–204.Coskuner, Y., & Ozdemir, Y. (1997). Effects of canning processes on the elements content of cultivated mushrooms (Agaricus bisporus). Food Chemistry, 60(4), 559–562.Cruz, R. M. S., Vieira, M. C., Fonseca, S. C., & Silva, C. L. M. (2011). Impact of thermal blanching and thermosonication treatments on watercress (Nasturtium officinale) quality: thermosonication process optimisation and microstructure evaluation. Food and Bioprocess Technology, 4(7), 1197–1204.De Gennaro, L., Cavella, S., Romano, R., & Masi, P. (1999). The use of ultrasound in food technology I: inactivation of peroxidase by thermosonication. Journal of Food Engineering, 39, 401–407.De la Fuente, S., Riera, E., Acosta, V. M., Blanco, A., & Gallego-Juárez, J. A. (2006). Food drying process by power ultrasound. Ultrasonics, 44, 523–527.Delgado, A. E., Zheng, L., & Sun, D. W. (2009). Influence of ultrasound on freezing rate of immersion-frozen apples. Food and Bioprocess Technology, 2, 263–270.Devece, C., Rodríguez-López, J. N., Fenoll, J. T., Catalá, J. M., De los Reyes, E., & García-Cánovas, F. (1999). Enzyme inactivation analysis for industrial blanching applications: comparison of microwave, conventional, and combination heat treatments on mushroom polyphenoloxidase activity. Journal of Agricultural and Food Chemistry, 47(11), 4506–4511.Fernandes, F. A. N., & Rodrigues, S. (2007). Ultrasound as pre-treatment for drying of fruits: dehydration of banana. Journal of Food Engineering, 82, 261–267.Gabaldón-Leyva, C. A., Quintero-Ramos, A., Barnard, J., Balandrán-Quintana, R. R., Talamás-Abbud, R., & Jiménez-Castro, J. (2007). Effect of ultrasound on the mass transfer and physical changes in brine bell pepper at different temperatures. Journal of Food Engineering, 81, 374–379.Gallego-Juárez, J. A., Riera, E., De la Fuente, S., Rodríguez-Corral, G., Acosta-Aparicio, V. M., & Blanco, A. (2007). Application of high-power ultrasound for dehydration of vegetables: processes and devices. Drying Technology, 25, 1893–1901.Gamboa-Santos, J., Montilla, A., Soria, A. C., & Villamiel, M. (2012). Effects of conventional and ultrasound blanching on enzyme inactivation and carbohydrate content of carrots. European Food Research and Technology, 234, 1071–1079.García-Pérez, J. V., Cárcel, J. A., De la Fuente, S., & Riera, E. (2006). Ultrasonic drying of foodstuff in a fluidized bed. Parametric study. Ultrasonics, 44, 539–543.García-Pérez, J. V., Cárcel, J. A., Riera, E., Rosselló, C., & Mulet, A. (2012). Intensification of low-temperature drying by using ultrasound. Drying Technology, 30, 1199–1208.Gonzáles-Fandos, E., Giménez, M., Olarte, C., Sanz, S., & Simón, A. (2000). Effect of packaging conditions on the growth of microorganisms and the quality characteristics of fresh mushrooms (Agaricus bisporus) stored at inadequate temperatures. Journal of Applied Microbiology, 89, 624–632.Gormley, T. R. (1975). Chill storage of mushrooms. Journal of the Science of Food and Agriculture, 26, 401–411.Gouzi, H., Depagne, C., & Coradin, T. (2012). Kinetics and thermodynamics of thermal inactivation of polyfenol oxidase in an aqueous extract from Agaricus bisporus. Journal of Agricultural and Food Chemistry, 60, 500–506.Holdsworth, S. D. (1997). Thermal processing of packaged foods. London: Chapman Hall.Horžić, D., Jambrak, A. R., Belščak-Cvitanović, A., Komes, D., & Lelas, V. (2012). Comparison of conventional and ultrasound assisted extraction techniques of yellow tea and bioactive composition of obtained extracts. Food and Bioprocess Technology, 5, 2858–2870.Jambrak, A. R., Mason, T. J., Paniwnyk, L., & Lelas, V. (2007a). Ultrasonic effect on pH, electric conductivity, and tissue surface of button mushrooms, brussels sprouts and cauliflower. Czech Journal of Food Science, 25, 90–99.Jambrak, A. R., Mason, T. J., Paniwnyk, L., & Lelas, V. (2007b). Accelerated drying of button mushrooms, Brussels sprouts and cauliflower by applying power ultrasound and its rehydration properties. Journal of Food Engineering, 81, 88–97.Jasinski, E. M., Stemberger, B., Walsh, R., & Kilara, A. (1984). Ultra structural studies of raw and processed tissue of the major cultivated mushroom, Agaricus bisporus. Food Microstructure, 3, 191–196.Jolivet, S., Arpin, N., Wicher, H. J., & Pellon, G. (1998). Agaricus bisporus browning: a review. Mycological Research, 102, 1459–1483.Konanayakam, M., & Sastry, S. K. (1988). Kinetics of shrinkage of mushroom during blanching. Journal of Food Science, 53(5), 1406–1411.Kotwaliwale, N., Bakane, P., & Verma, A. (2007). Changes in textural and optical properties of oyster mushroom during hot air drying. Journal of Food Engineering, 78(4), 1207–1211.Leadley C. & Williams A. (2002). Power ultrasound—current and potential applications for food processing, Review No 32, Campden and Chorleywood Food Research Association.Lespinard, A. R., Goñi, S. M., Salgado, P. R., & Mascheroni, R. H. (2009). Experimental determination and modeling of size variation, heat transfer and quality indexes during mushroom blanching. Journal of Food Engineering, 92, 8–17.Lima, M., & Sastry, S. K. (1990). Influence of fluid rheological properties and particle location on ultrasound-assisted heat transfer between liquid and particles. Journal of Food Science, 55(4), 1112–1115.López, P., & Burgos, J. (1995). Peroxidase stability and reactivation after heat treatment and manothermosonication. Journal of Food Science, 60(3), 551–553.López, P., Sala, F. J., Fuente, J. L., Cardon, S., Raso, J., & Burgos, J. (1994). Inactivation of peroxidase lipoxigenase and phenol oxidase by manothermosonication. Journal of Agricultural and Food Chemistry, 42(2), 253–256.Mansfield, T. (1962). High temperature-short time sterilization. Proceedings First International Congress on Food Science and Technology, 4, 311–316.Mason T. J. (1998). Power ultrasound in food processing—the way forward. In M. J. W. Povey & T. J. Mason (Eds.), Ultrasound in Food Processing (pp 103–126). Blackie Academic & Professional, London.McArdle F. J. & Curwen D. (1962). Some factors influencing shrinkage of canned mushrooms. Mushroom Science, 5, 547–557.McArdle, F. J., Kuhn, G. D., & Beelman, R. B. (1974). Influence of vacuum soaking on yield and quality of canned mushrooms. Journal of Food Science, 39, 1026–1028.Mohapatra, D., Bira, Z. M., Kerry, J. P., Frías, J. M., & Rodrigues, F. A. (2010). Postharvest hardness and color evolution of White button mushrooms (Agaricus bisporus). Journal of Food Science, 75(3), 146–152.Ohlsson, T. (1980). Temperature dependence of sensory quality changes during thermal processing. Journal of Food Science, 45(4), 836–847.Ortuño, C., Martínez-Pastor, M., Mulet, A., & Benedito, J. (2013). Application of high power ultrasound in the supercritical carbon dioxide inactivation of Saccharomyces cerevisiae. Food Research International, 51, 474–481.Peralta-Jimenez, L., & Cañizares-Macías, M. P. (2012). Ultrasound-assisted method for extraction of theobromine and caffeine from cacao seeds and chocolate products. Food and Bioprocess Technology, 6, 3522–3529.Rodríguez-López, J. N., Fenoll, N. G., Tudela, J., Devece, C., Sánchez-Hernández, D., De los Reyes, D., et al. (1999). Thermal inactivation of mushroom polyphenoloxidase employing 2450 MHz microwave radiation. Journal of Agricultural Food Chemistry, 47, 3028–3035.Sala, F., Burgos, J., Condon, S., Lopez, P., & Raso, J. (1995). Effect of heat and ultrasound on microorganisms and enzymes. In G. W. Gould (Ed.), New methods of food preservation (1st ed., pp. 176–204). Glasgow: Blackie Academic and professional.Sanjuán, N., Hernando, I., Lluch, M. A., & Mullet, A. (2005). Effects of low temperature blanching on texture, microstructure and rehydration capacity of carrots. Journal of the Science of Food and Agriculture, 85, 2071–2076.Santos, M. V., & Lespinard, A. R. (2011). Numerical simulation of mushrooms during freezing using the FEM and an enthalpy—Kirchhoff formulation. Heat and Mass Transfer, 47, 1671–1683.Sastry, S. K., Beelman, R. B., & Speroni, J. J. (1985). A three-dimensional finite element model for thermally induced changes in foods: application to degradation of agaritine in canned mushrooms. Journal of Food Science, 50(5), 1293–1299.Sastry, S. K., Shen, G. Q., & Blaisdel, J. L. (1989). Effect of ultrasonic vibration on fluid-to-particule convective heat transfer coefficients. Journal of Food Science, 54(1), 229–230.Sensoy, I., & Sastry, S. K. (2004). Ohmic blanching of mushrooms. Journal of Food Process Engineering, 27(1), 1–15.Sheen, S., & Hayakawa, K. (1991). Finite difference simulation for heat conduction with phase change in an irregular food domain with volumetric change. International Journal of Heat and Mass Transfer, 34(6), 1337–1346.Simal, S., Benedito, J., Sanchez, E. S., & Rossello, C. (1998). Use of ultrasound to increase mass transport rates during osmotic dehydration. Journal of Food Engineering, 36, 323–336.Siró, I., Vén, C., Balla, C., Jónás, G., Zeke, I., & Friedrich, L. (2009). Application of an ultrasonic assisted curing technique for improving the diffusion of sodium chloride in porcine meat. Journal of Food Engineering, 91, 353–362.Soria, A. C., & Villamiel, M. (2010). Effect of ultrasound on the technological properties and bioactivity in foods: a review. Trends in Food Science and Technology, 21, 323–331.Verlinden, B. E., Yuksel, D., Baheri, M., De Baerdemaeker, J., & Van Dijk, C. (2000). Low temperature blanching effect on the changes in mechanical properties during subsequent cooking of three potato cultivars. International Journal of Food Science and Technology, 35, 331–340.Wu, C. M., Wu, J. L.-P., Chen, C.-C., & Chou, C.-C. (1981). Flavor recovery from mushroom blanching water. In G. Charalambous & G. Inglett (Eds.), The quality of foods and beverages: chemistry and technology, vol. 1. New York: Academic Press.Zivanovic, S., & Buescher, R. (2004). Changes in mushroom texture and cell wall composition affected by thermal processing. Journal of Food Science, 69, 44–48

    A search for point sources of EeV photons

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    Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa

    Reconstruction of inclined air showers detected with the Pierre Auger Observatory

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    We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than 6060^\circ detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analyses including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.Comment: 27 pages, 19 figures, accepted for publication in Journal of Cosmology and Astroparticle Physics (JCAP

    Multiplicity dependence of jet-like two-particle correlations in p-Pb collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

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    Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7 <pT,assoc<pT,trig< < p_{\rm{T}, assoc} < p_{\rm{T}, trig} < 5.0 GeV/cc is examined, to include correlations induced by jets originating from low momen\-tum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range η<0.9|\eta|<0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the non-jet-like components. The yields in the jet-like peaks are found to be invariant with event multiplicity with the exception of events with low multiplicity. This invariance is consistent with the particles being produced via the incoherent fragmentation of multiple parton--parton scatterings, while the yield related to the previously observed ridge structures is not jet-related. The number of uncorrelated sources of particle production is found to increase linearly with multiplicity, suggesting no saturation of the number of multi-parton interactions even in the highest multiplicity p-Pb collisions. Further, the number scales in the intermediate multiplicity region with the number of binary nucleon-nucleon collisions estimated with a Glauber Monte-Carlo simulation.Comment: 23 pages, 6 captioned figures, 1 table, authors from page 17, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/161

    Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}=2.76 TeV

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    The elliptic, v2v_2, triangular, v3v_3, and quadrangular, v4v_4, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions and (anti-)protons in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range η<0.8|\eta|<0.8 at different collision centralities and as a function of transverse momentum, pTp_{\rm T}, out to pT=20p_{\rm T}=20 GeV/cc. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for pT>8p_{\rm T}>8 GeV/cc. The small pTp_{\rm T} dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to pT=8p_{\rm T}=8 GeV/cc. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least pT=8p_{\rm T}=8 GeV/cc indicating that the particle type dependence persists out to high pTp_{\rm T}.Comment: 16 pages, 5 captioned figures, authors from page 11, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/186
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