Avaliação econômica da terminação de bovinos de corte em pastagem irrigada

Foi avaliada a viabilidade econômica de três sistemas de produção por meio da mensuração dos custos de produção e da análise dos indicadores financeiros. Os três sistemas (S1, S2 e S3), situados na fronteira oeste do Rio Grande do Sul, foram avaliados no período de outubro de 2010 a outubro de 2011. A pastagem estabelecida no S1 foi de azevém (Lolium multiflorumLam)e trevo branco (Trifolium repensLam); no S2, trevo branco, trevo vermelho (Trifolium pratenseLam), cornichão (Lotus corniculatusLam), azevém e aveia preta (Avena strigosaSchreb); e no S3, azevém, cornichão, trevo branco e trevo vermelho. Os animais foram pesados na entrada e na saída das pastagens. A coleta de dados para mensuração do custo foi realizada mensalmente utilizando-se planilhas apropriadas. As produtividades foram de 369, 772 e 637kg/ha para os sistemas S1, S2 e S3, respectivamente. O S2 apresentou o maior custo total (R$2.101,59/ha), enquanto o menor foi obtido pelo S1 (R$ 1.626,93/ha). Na análise do custo operacional médio dos três sistemas, os itens que apresentaram maiores valores foram a implantação de pastagem, a energia elétrica, a manutenção da pastagem e a depreciação. Quanto às margens, os sistemas S1, S2 e S3 apresentaram, respectivamente, R$33,46, 1.162,55 e 701,01/ha para margem bruta; R$ -63,51, 955,40 e 541,05/ha para margem operacional; e R$ -583,18, 291,61 e -28,99/ha para lucro total. A rentabilidade foi de -0,47, 4,37 e 3,01% e a lucratividade foi de -5,94, 39,92 e 27,38% para o S1, S2 e S3, respectivamente. A irrigação de pastagens para terminação de bovinos é viável economicamente, no entanto a sua adoção deve sempre visar a altas produtividades zootécnicas devido ao seu elevado custo de produção

Museum collections indicate bird defaunation in a biodiversity hotspot

Abstract Ipanema National Forest, southeastern Brazil, once contained 340 bird species. Forest cover suffered for centuries from log exploitation and, as a result, most of the remaining forests are now an impoverished subset of the original vegetation. We show how the bird community changed over time by comparing historical and recent records. Currently, 228 species can be recorded, for a compilation of 410 species, of which 359 are documented. Some 89 forest species with historical records failed to be detected in recent surveys. Of the 72 Atlantic Forest or Cerrado endemic species, no more than 29 (40%) are still found. The bird community changed from one which used to be related to coastline rain forests to another, which relates more to drier semideciduous forests of the interior

Observation of quantum entanglement with top quarks at the ATLAS detector

Entanglement is a key feature of quantum mechanics with applications in fields such as metrology, cryptography, quantum information and quantum computation. It has been observed in a wide variety of systems and length scales, ranging from the microscopic to the macroscopic. However, entanglement remains largely unexplored at the highest accessible energy scales. Here we report the highest-energy observation of entanglement, in top–antitop quark events produced at the Large Hadron Collider, using a proton–proton collision dataset with a centre-of-mass energy of √s = 13 TeV and an integrated luminosity of 140 inverse femtobarns (fb)−1 recorded with the ATLAS experiment. Spin entanglement is detected from the measurement of a single observable D, inferred from the angle between the charged leptons in their parent top- and antitop-quark rest frames. The observable is measured in a narrow interval around the top–antitop quark production threshold, at which the entanglement detection is expected to be significant. It is reported in a fiducial phase space defined with stable particles to minimize the uncertainties that stem from the limitations of the Monte Carlo event generators and the parton shower model in modelling top-quark pair production. The entanglement marker is measured to be D = −0.537 ± 0.002 (stat.) ± 0.019 (syst.) for 340 GeV < mtt < 380 GeV. The observed result is more than five standard deviations from a scenario without entanglement and hence constitutes the first observation of entanglement in a pair of quarks and the highest-energy observation of entanglement so far

The performance of missing transverse momentum reconstruction and its significance with the ATLAS detector using 140 fb-1 of √s = 13 TeV TeV pp collisions

Abstract This paper presents the reconstruction of missing transverse momentum ( $$p_{\text {T}}^{\text {miss}}$$ p T miss ) in proton–proton collisions, at a center-of-mass energy of 13 TeV. This is a challenging task involving many detector inputs, combining fully calibrated electrons, muons, photons, hadronically decaying $$\tau$$ τ -leptons, hadronic jets, and soft activity from remaining tracks. Possible double counting of momentum is avoided by applying a signal ambiguity resolution procedure which rejects detector inputs that have already been used. Several $$p_{\text {T}}^{\text {miss}}$$ p T miss ‘working points’ are defined with varying stringency of selections, the tightest improving the resolution at high pile-up by up to 39% compared to the loosest. The $$p_{\text {T}}^{\text {miss}}$$ p T miss performance is evaluated using data and Monte Carlo simulation, with an emphasis on understanding the impact of pile-up, primarily using events consistent with leptonic Z decays. The studies use $$140~\text {fb}^{-1}$$ 140 fb - 1 of data, collected by the ATLAS experiment at the Large Hadron Collider between 2015 and 2018. The results demonstrate that $$p_{\text {T}}^{\text {miss}}$$ p T miss reconstruction, and its associated significance, are well understood and reliably modelled by simulation. Finally, the systematic uncertainties on the soft $$p_{\text {T}}^{\text {miss}}$$ p T miss component are calculated. After various improvements the scale and resolution uncertainties are reduced by up to $$76\%$$ 76 % and $$51\%$$ 51 % , respectively, compared to the previous calculation at a lower luminosity

Deep generative models for fast photon shower simulation in ATLAS

The need for large-scale production of highly accurate simulated event samples for the extensive physics programme of the ATLAS experiment at the Large Hadron Collider motivates the development of new simulation techniques. Building on the recent success of deep learning algorithms, variational autoencoders and generative adversarial networks are investigated for modelling the response of the central region of the ATLAS electromagnetic calorimeter to photons of various energies. The properties of synthesised showers are compared with showers from a full detector simulation using geant4. Both variational autoencoders and generative adversarial networks are capable of quickly simulating electromagnetic showers with correct total energies and stochasticity, though the modelling of some shower shape distributions requires more refinement. This feasibility study demonstrates the potential of using such algorithms for ATLAS fast calorimeter simulation in the future and shows a possible way to complement current simulation techniques