Effects of external nutrient sources and extreme weather events on the nutrient budget of a Southern European coastal lagoon

The seasonal and annual nitrogen (N), phosphorus (P), and carbon (C) budgets of the mesotidal Ria Formosa lagoon, southern Portugal, were estimated to reveal the main inputs and outputs, the seasonal patterns, and how they may influence the ecological functioning of the system. The effects of extreme weather events such as long-lasting strong winds causing upwelling and strong rainfall were assessed. External nutrient inputs were quantified; ocean exchange was assessed in 24-h sampling campaigns, and final calculations were made using a hydrodynamic model of the lagoon. Rain and stream inputs were the main freshwater sources to the lagoon. However, wastewater treatment plant and groundwater discharges dominated nutrient input, together accounting for 98, 96, and 88 % of total C, N, and P input, respectively. Organic matter and nutrients were continuously exported to the ocean. This pattern was reversed following extreme events, such as strong winds in early summer that caused upwelling and after a period of heavy rainfall in late autumn. A principal component analysis (PCA) revealed that ammonium and organic N and C exchange were positively associated with temperature as opposed to pH and nitrate. These variables reflected mostly the benthic lagoon metabolism, whereas particulate P exchange was correlated to Chl a, indicating that this was more related to phytoplankton dynamics. The increase of stochastic events, as expected in climate change scenarios, may have strong effects on the ecological functioning of coastal lagoons, altering the C and nutrient budgets.Portuguese Science and Technology Foundation (FCT) [POCI/MAR/58427/2004, PPCDT/MAR/58427/2004]; Portuguese Science and Technology Foundation (FCT

Earth blocks stabilized by cow-dung

WOS:000379589500010International audienceIn developing countries, most of the population cannot afford conventional building blocks made with the sand-cement mixture. In addition, these blocks do not provide thermal comfort and have a high embodied energy compared to vernacular materials. The main objective of this work was to produce low cost, resistant and durable (good resistance to water) blocks with a thermal behaviour enabling quality comfort indoor. For that purpose, the effects of cow-dung on microstructural changes in earth blocks (adobes) are investigated by means of X-ray diffraction, thermal gravimetric analyses, scanning electronic microscopy coupled with energy dispersive spectrometry, and video microscopy. The effects of these changes on the physical properties (water absorption and linear shrinkage) and mechanical properties (flexural and compressive strengths) of adobe blocks are evaluated. It is shown that cow-dung reacts with kaolinite and fine quartz to produce insoluble silicate amine, which glues the isolated soil particles together. Moreover, the significant presence of fibres in cow-dung prevents the propagation of cracks in the adobes and thus reinforces the material. The above phenomena make the adobe microstructure homogeneous with an apparent reduction of the porosity. The major effect of cow-dung additions is a significant improvement in the water resistance of adobe, which leads to the conclusion that adobes stabilized by cow-dung are suitable as building materials in wet climates

Effect of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS)

The aim of this paper is to study the influence of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS). Mechanical strength of alkali activated mortars cured at 65 °C was assessed for different curing times (4¿168 h) using 10 molal NaOH solution as alkaline activator. Compressive strength values around 77 MPa after three days of curing at 65 °C were obtained. 1·68 MPa/h compressive strength gain rate was observed in the first 12 h, decreasing to 0·95 MPa/h for the period of 12¿72 h. The progress of geopolymeric reaction was monitored by means of TGA and, electrical conductivity and pH measurements in an aqueous suspension. Significant decrease in pH and electrical conductivity were observed in the 4¿72 h period, demonstrating the geopolymerization process. Furthermore, SEM images showed an important amount of (N, C)ASH gel and low porosity of the developed matrix.To the Ministerio de Ciencia e Innovacion (MICINN) of the Spanish Government (BIA2011-26947) and also to FEDER for funding and to Vitrominerals company for supplying VCAS samples.Mitsuuchi Tashima, M.; Soriano Martínez, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Paya Bernabeu, JJ. (2013). Effect of curing time on the microstructure and mechanical strength development of alkali activated binders based on vitreous calcium aluminosilicate (VCAS). Bulletin of Materials Science. 36:245-249. https://doi.org/10.1007/s12034-013-0466-zS24524936Bernal S A, Gutiérrez R M, Pedraza A L, Provis J L, Rodriguez E D and Delvasto S 2011 Cem. Concr. Res. 41 1Criado M, Fernández-Jiménez A, Sobrados I, Palomo A and Sanz J 2011 J. Eur. Ceram. Soc. avaiable onlineDavidovits J 2008 Geopolymer chemistry and applications Institute Geopolymere, Saint-Quentin, FranceDuxson P, Fernández-Jiménez A, Provis J L, Lukey G C, Palomo A and van Deventer J S J 2007 J. Mater. Sci. 47 2917Fernández-Jiménez A, Palomo A and Criado M 2005 Cem. Concr. Res. 35 1204Hossain A B, Shrazi S A, Persun J and Neithalath N 2008 J. Transp. Res. Board 2070 32Komnitsas K and Zaharaki D 2007 Miner. Eng. 20 1261Lampris C, Lupo R and Cheeseman C R 2009 Waste Manage. 29 368Lin T, Jia D, Wang M, He P and Liang D 2009 Bull. Mater. Sci. 32 77Lloyd R R, Provis J L and van Deventer J S J 2009 J. Mater. Sci. 44 608Marín-López C, Reyes Araiza J L, Manzano-Ramírez A, Rubio Avalos J C, Perez-Bueno J J, Muñiz-Villareal M S, Ventura-Ramos E and Vorobiev Y 2009 Inorg. Mater. 45 1429Najafi Kani E, Allahverdi A and Provis J L 2012 Cem. Concr. Comp. 34 25Neithalath N, Persun J and Hossain A 2009 Cem. Concr. Res. 39 473Pacheco-Torgal F, Castro-Gomes J and Jalali S 2008a Constr. Build. Mater. 22 1315Pacheco-Torgal F, Castro-Gomex J and Jalali S 2008b Constr. Build. Mater. 22 1201Pacheco-Torgal F, Castro-Gomex J and Jalali S 2008c Constr. Build. Mater. 22 2212Payá J, Borrachero M V, Monzó J, Soriano L and Tashima M M 2012 Mater. Lett. 74 223Puertas F, Martínez-Ramírez S, Alonso S and Vázquez T 2000 Cem. Concr. Res. 30 1625Puertas F, Barba A, Gazulla M F, Gómez M P, Palacios M and Martínez-Ramírez S 2006 Mater. Construc. 56 73Reig L, Tashima M M, Borrachero M V, Monzó J and Payá J 2010 II Simposio aprovechamiento de residuos agro-industriales como fuente sostenible de materiales de construcción p. 83Rodriguez E D, Bernal S A, Provis J, Payá J, Monzó J and Borrachero M V 2012 Cem. Concr. Comp. (submitted)Tashima M M, Borrachero M V, Monzó J, Soriano L and Payá J 2009 COMATCOMP09 p.421Tashima M M, Akasaki J L, Castaldelli V N, Soriano L, Monzó J, Payá J and Borrachero M V 2012 Mater. Lett. 80 50Xu H and van Deventer J S J 2000 Int. J. Miner. Process. 59 247Yao X, Zhang Z, Zhu H and Chen Y 2009 Thermochim. Acta 493 49Zivica V 2004 Bull. Mater. Sci. 27 179Zivica V, Balkovic S and Drabik M 2011 Constr. Build. Mater. 25 220

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Measurement of the cross-section of high transverse momentum vector bosons reconstructed as single jets and studies of jet substructure in pp collisions at √s = 7 TeV with the ATLAS detector

This paper presents a measurement of the cross-section for high transverse momentum W and Z bosons produced in pp collisions and decaying to all-hadronic final states. The data used in the analysis were recorded by the ATLAS detector at the CERN Large Hadron Collider at a centre-of-mass energy of √s = 7 TeV;{\rm Te}{\rm V}$and correspond to an integrated luminosity of$4.6\;{\rm f}{{{\rm b}}^{-1}}$. The measurement is performed by reconstructing the boosted W or Z bosons in single jets. The reconstructed jet mass is used to identify the W and Z bosons, and a jet substructure method based on energy cluster information in the jet centre-of-mass frame is used to suppress the large multi-jet background. The cross-section for events with a hadronically decaying W or Z boson, with transverse momentum${{p}_{{\rm T}}}\gt 320\;{\rm Ge}{\rm V}$and pseudorapidity$|\eta |\lt 1.9$, is measured to be${{\sigma }_{W+Z}}=8.5\pm 1.7$ pb and is compared to next-to-leading-order calculations. The selected events are further used to study jet grooming techniques

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

Search for R-parity-violating supersymmetry in events with four or more leptons in sqrt(s) =7 TeV pp collisions with the ATLAS detector

A search for new phenomena in final states with four or more leptons (electrons or muons) is presented. The analysis is based on 4.7 fb−1 of $\sqrt{s}=7\;\mathrm{TeV}$ proton-proton collisions delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in two signal regions: one that requires moderate values of missing transverse momentum and another that requires large effective mass. The results are interpreted in a simplified model of R-parity-violating supersymmetry in which a 95% CL exclusion region is set for charged wino masses up to 540 GeV. In an R-parity-violating MSUGRA/CMSSM model, values of m 1/2 up to 820 GeV are excluded for 10 < tan β < 40

Search for high-mass resonances decaying to dilepton final states in pp collisions at s√=7 TeV with the ATLAS detector

The ATLAS detector at the Large Hadron Collider is used to search for high-mass resonances decaying to an electron-positron pair or a muon-antimuon pair. The search is sensitive to heavy neutral Z′ gauge bosons, Randall-Sundrum gravitons, Z * bosons, techni-mesons, Kaluza-Klein Z/γ bosons, and bosons predicted by Torsion models. Results are presented based on an analysis of pp collisions at a center-of-mass energy of 7 TeV corresponding to an integrated luminosity of 4.9 fb−1 in the e + e − channel and 5.0 fb−1 in the μ + μ −channel. A Z ′ boson with Standard Model-like couplings is excluded at 95 % confidence level for masses below 2.22 TeV. A Randall-Sundrum graviton with coupling k/MPl=0.1 is excluded at 95 % confidence level for masses below 2.16 TeV. Limits on the other models are also presented, including Technicolor and Minimal Z′ Models