| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
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| 3. |
- Amati, L., et al.
(författare)
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The THESEUS space mission concept : science case, design and expected performances
- 2018
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Ingår i: Advances in Space Research. - : ELSEVIER SCI LTD. - 0273-1177 .- 1879-1948. ; 62:1, s. 191-244
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Tidskriftsartikel (refereegranskat)abstract
- THESEUS is a space mission concept aimed at exploiting Gamma-Ray Bursts for investigating the early Universe and at providing a substantial advancement of multi-messenger and time-domain astrophysics. These goals will be achieved through a unique combination of instruments allowing GRB and X-ray transient detection over a broad field of view (more than 1 sr) with 0.5-1 arcmin localization, an energy band extending from several MeV down to 0.3 keV and high sensitivity to transient sources in the soft X-ray domain, as well as on-board prompt (few minutes) follow-up with a 0.7 m class IR telescope with both imaging and spectroscopic capabilities. THESEUS will be perfectly suited for addressing the main open issues in cosmology such as, e.g., star formation rate and metallicity evolution of the inter-stellar and intra-galactic medium up to redshift similar to 10, signatures of Pop III stars, sources and physics of re-ionization, and the faint end of the galaxy luminosity function. In addition, it will provide unprecedented capability to monitor the X-ray variable sky, thus detecting, localizing, and identifying the electromagnetic counterparts to sources of gravitational radiation, which may be routinely detected in the late '20s/early '30s by next generation facilities like aLIGO/ aVirgo, eLISA, KAGRA, and Einstein Telescope. THESEUS will also provide powerful synergies with the next generation of multi-wavelength observatories (e.g., LSST, ELT, SKA, CTA, ATHENA).
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| 5. |
- Brito de Figueiredo, Maria Clea, et al.
(författare)
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Reducing the impact of irrigated crops on freshwater availability : the case of Brazilian yellow melons
- 2014
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Ingår i: The International Journal of Life Cycle Assessment. - : Springer Science and Business Media LLC. - 0948-3349 .- 1614-7502. ; 19:2, s. 437-448
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Tidskriftsartikel (refereegranskat)abstract
- This study quantifies freshwater consumption throughout the life cycle of Brazilian exported yellow melons and assesses the resulting impact on freshwater availability. Results are used to identify improvement options. Moreover, the study explores the further impact of variations in irrigation volume, yield, and production location. The product system boundary encompasses production of seeds, seedlings, and melon plants; melon packing; disposal of solid farm waste; and farm input and melon transportation to European ports. The primary data in the study were collected from farmers in order to quantify freshwater consumption related to packing and to production of seeds, seedlings, and melons. Open-field melon irrigation was also estimated, considering the region's climate and soil characteristics. Estimated and current water consumptions were compared in order to identify impact reduction opportunities. Sensitivity analysis was used to evaluate variations in the impact because of changes in melon field irrigation, yield, and farm location. This study shows that the average impact on freshwater availability of 1 kg of exported Brazilian yellow melons is 135 l H2O-e, with a range from 17 to 224 l H2O-e depending on the growing season's production period. Irrigation during plant production accounts for 98 % of this impact. Current melon field water consumption in the Low Jaguaribe and A double dagger u region is at least 39 % higher than necessary, which affects the quality of fruits and yield. The impact of melon production in other world regions on freshwater availability may range from 0.3 l H2O-e/kg in Costa Rica to 466 l H2O-e/kg in the USA. The impact of temporary crops, such as melons, on water availability should be presented in ranges, instead of as an average, since regional consumptive water and water stress variations occur in different growing season periods. Current and estimated water consumption for irrigation may also be compared in order to identify opportunities to achieve optimization and reduce water availability impact.
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| 6. |
- de Figueiredo, Maria Clea Brito, et al.
(författare)
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The carbon footprint of exported Brazilian yellow melon
- 2013
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 47, s. 404-414
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Tidskriftsartikel (refereegranskat)abstract
- The carbon footprint of food has become important for producers worldwide as consumers and retail companies increasingly base their purchase decisions on carbon footprint labels. In this context, our objectives is to assess the carbon footprint (CF) of Brazilian yellow melon exported from the Low Jaguaribe and Acu region, including an uncertainty assessment, and to evaluate reduction potentials and improvement options. Exporting farms located in this region account for about 99 percent of Brazilian melon exports, mainly to the United Kingdom and the Netherlands. To determine the CF, we followed Life Cycle Assessment, according to ISO standards (14040 and 14044). The results are expressed in kg of CO2-eq/t of exported melon. The production system encompasses processes in the Low Jaguaribe and Acu region (such as seedling, plant production, packing, and disposal of solid wastes from farms), upstream processes (including the production and transportation of inputs, such as seeds, plastics, and fertilizers), and downstream processes (melon transport). The total yellow melon CF in the reference situation is 710 kg CO2-eq/t exported melon. However, scenario results indicate that this value can be reduced by 44 percent if melon fields are located in pre-existing agricultural areas, nitrogen fertilization is reduced, and no plastic field trays are used in melon production. GHG emissions from melon transport are relatively unimportant in the total CF. These results provide melon producers with an insight into the CF of their product, and options to reduce it.
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| 7. |
- Ran, Ylva, et al.
(författare)
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Environmental assessment of diets: overview and guidance on indicator choice
- 2024
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Ingår i: The Lancet Planetary Health. - : Elsevier BV. - 2542-5196. ; 8:3, s. e172-e187
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Forskningsöversikt (refereegranskat)abstract
- Comprehensive but interpretable assessment of the environmental performance of diets involves choosing a set of appropriate indicators. Current knowledge and data gaps on the origin of dietary foodstuffs restrict use of indicators relying on site-specific information. This Personal View summarises commonly used indicators for assessing the environmental performance of diets, briefly outlines their benefits and drawbacks, and provides recommendations on indicator choices for actors across multiple fields involved in activities that include the environmental assessment of diets. We then provide recommendations on indicator choices for actors across multiple fields involved in activities that use environmental assessments, such as health and nutrition experts, policy makers, decision makers, and private-sector and public-sector sustainability officers. We recommend that environmental assessment of diets should include indicators for at least the five following areas: climate change, biosphere integrity, blue water consumption, novel entities, and impacts on natural resources (especially wild fish stocks), to capture important environmental trade-offs. If more indicators can be handled in the assessment, indicators to capture impacts related to land use quantity and quality and green water consumption should be used. For ambitious assessments, indicators related to biogeochemical flows, stratospheric ozone depletion, and energy use can be added.
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