Browsing by Issue Date, starting with "2016-08-01"
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- Water quality monitoring in the Paul do Boquilobo Biosphere ReservePublication . Baptista, C.; Santos, LuisThe Paul do Boquilobo is an important wetland ecosystem classified by Unesco as a MAB Biosphere reserve also awarded Ramsar site status, representing one of the most important habitats for the resident nesting colony of Cattle Egret (Bulbucus ibis). Yet owing to its location, it suffers from human induced impacts which include industrial and domestic effluent discharges as well as agricultural land use which have negatively impacted water quality. The current study reports the results obtained from the introductory monitoring programme of surface water quality in the Nature Reserve to emphasize the detrimental impact of the anthropogenic activities in the water quality of such an important ecosystem. The study involved physicochemical and biotic variables, microbial parameters and biological indicators. Results after 3 years of monitoring bring to evidence a poor water quality further impaired by seasonal patterns. Statistical analysis of data attributed water quality variation to 3 main parameters – pH, dissolved oxygen and nitrates, indicating heavy contamination loads from both organic and agricultural sources. Seasonality plays a role in water flow and climatic conditions, where sampling sites presented variable water quality data, suggesting a depurative function of the wetland.
- Measurement of the inclusive isolated prompt photon cross section in pp collisions at $ \sqrt{s}=8 $ TeV with the ATLAS detectorPublication . ATLAS collaboration (2862 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oleiro Seabra, Luis Filipe; Onofre, António; Palma, Alberto; Pedro, Rute; Pina, João Antonio; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutA measurement of the cross section for the inclusive production of isolated prompt photons in proton-proton collisions at a centre-of-mass energy of $ \sqrt{s}=8 $ TeV is presented. The measurement covers the pseudorapidity ranges |η$^{γ}$ | < 1.37 and 1.56 ≤ |η$^{γ}$ | < 2.37 in the transverse energy range 25 < E$_{T}^{γ}$ < 1500 GeV. The results are based on an integrated luminosity of 20.2 fb$^{−1}$, recorded by the ATLAS detector at the LHC. Photon candidates are identified by combining information from the calorimeters and the inner tracker. The background is subtracted using a data-driven technique, based on the observed calorimeter shower-shape variables and the deposition of hadronic energy in a narrow cone around the photon candidate. The measured cross sections are compared with leading-order and next-to-leading order perturbative QCD calculations and are found to be in a good agreement over ten orders of magnitude.
- Measurement of the double-differential high-mass Drell-Yan cross section in pp collisions at $ \sqrt{s}=8 $ TeV with the ATLAS detectorPublication . ATLAS collaboration (2852 authors); Aguilar-Saavedra, Juan Antonio; Amor Dos Santos, Susana Patricia; Anjos, Nuno; Araque, Juan Pedro; Cantrill, Robert; Carvalho, João; Castro, Nuno Filipe; Conde Muiño, Patricia; Da Cunha Sargedas De Sousa, Mario Jose; Fiolhais, Miguel; Galhardo, Bruno; Gomes, Agostinho; Gonçalo, Ricardo; Jorge, Pedro; Lopes, Lourenco; Machado Miguens, Joana; Maio, Amélia; Maneira, José; Oleiro Seabra, Luis Filipe; Onofre, António; Palma, Alberto; Pedro, Rute; Santos, Helena; Saraiva, João; Silva, José; Tavares Delgado, Ademar; Veloso, Filipe; Wolters, HelmutThis paper presents a measurement of the double-differential cross section for the Drell-Yan Z/γ$^{∗}$ → ℓ$^{+}$ ℓ$^{−}$ and photon-induced γγ → ℓ$^{+}$ ℓ$^{−}$ processes where ℓ is an electron or muon. The measurement is performed for invariant masses of the lepton pairs, m$_{ℓℓ}$, between 116 GeV and 1500 GeV using a sample of 20.3 fb$^{−1}$ of pp collisions data at centre-of-mass energy of $ \sqrt{s}=8 $ TeV collected by the ATLAS detector at the LHC in 2012. The data are presented double differentially in invariant mass and absolute dilepton rapidity as well as in invariant mass and absolute pseudorapidity separation of the lepton pair. The single-differential cross section as a function of m$_{ℓℓ}$ is also reported. The electron and muon channel measurements are combined and a total experimental precision of better than 1% is achieved at low m$_{ℓℓ}$. A comparison to next-to-next-to-leading order perturbative QCD predictions using several recent parton distribution functions and including next-to-leading order electroweak effects indicates the potential of the data to constrain parton distribution functions. In particular, a large impact of the data on the photon PDF is demonstrated.