Microclimatic characterization and productivity of coffee plants grown under shade of pigeon pea in Southern Brazil Caracterização microclimática e produtividade de cafeeiros sombreados com guandu no Sul do Brasil

Recent studies on coffee (Coffea arabica L.) cultivation in agroforestry systems in Southern Brazil have shown the potential of partial shading to improve management of this crop. The objective of this work was to evaluate microclimatic conditions and their effects on coffee production of plants shaded with pigeon pea (Cajanus cajan) in comparison to unshaded ones, from May 2001 to August 2002 in Londrina, State of Paraná, Brazil. The appraised microclimatic characteristics were: global radiation, photosynthetic and radiation balance; air, leaf and soil temperatures; and soil humidity. Shading caused significant reduction in incident global solar radiation, photosynthetically active radiation and net radiation, and attenuated maximum leaf, air and soil temperatures, during the day. Shade also reduced the rate of cooling of night air and leaf temperatures, especially during nights with radiative frost. Soil moisture at 0-10 cm depth was higher under shade. The shaded coffee plants produced larger cherries due to slower maturation, resulting in larger bean size. Nevertheless, plants under shade emitted less plagiotropic branches, with smaller number of nodes per branch, and fewer nodes with fruits, resulting in a large reduction in coffee production. These results show the need to find an optimal tree density and management that do not compromise coffee production and protect against extreme temperatures.<br>Recentes estudos sobre cafeeiros (Coffea arabica L.) cultivados em sistemas agroflorestais no Sul do Brasil têm mostrado o potencial do sombreamento parcial no manejo desta cultura. O objectivo deste trabalho foi avaliar as condições do microclima e seus efeitos na produção de café sombreado com guandu (Cajanus cajan), em comparação ao cultivado a pleno sol, no período de maio de 2001 a agosto de 2002 em Londrina, PR. As características microclimáticas avaliadas foram: radiação global, fotossintética e saldo de radiação; temperaturas do ar, da folha e do solo; e umidade do solo. O sombreamento causou significativa redução na radiação solar global incidente, na radiação fotossinteticamente ativa e na radiação líquida, e atenuou as temperaturas máximas foliar, do ar e do solo, durante o dia. O sombreamento também evitou o declínio acentuado, durante a noite, das temperaturas do ar e da folha, especialmente durante noites com geadas de radiação. Os valores de umidade do solo, na camada 0-10 cm de profundidade, foram maiores nos cafeeiros sombreados. As plantas sombreadas produzem frutos maiores em virtude da maturação mais lenta, entretanto, emitem menos ramos plagiotrópicos, com menor número de nós por ramo e poucos nós com frutos, o que resulta na redução da produção de café. Estes resultados evidenciam a necessidade de se definir uma densidade ótima de sombreamento, que não comprometa a produção e proteja contra as temperaturas extremas

Análise comparativa das características da serrapilheira e do solo em cafezais (Coffea arabica L.) cultivados em sistema agroflorestal e em monocultura, na Zona da Mata MG Comparative analysis of litter and soil characteristics under coffee (Coffea arabica L.) crop in agroforestry and monoculture systems

O aporte de serrapilheira em sistemas agroflorestais pode melhorar as características químicas e físicas do solo, diminuir a erosão e permitir a manutenção da umidade no solo por mais tempo. Isso faz dele um sistema alternativo de produção de café em regiões com solos propensos à degradação. Este trabalho teve como objetivo realizar uma análise comparativa da quantidade e teor de nutrientes da serrapilheira e das características de fertilidade e do teor de umidade dos solos, em cafeeiros cultivados sob sistemas agroflorestal e solteiro. A pesquisa foi realizada na Zona da Mata mineira, durante o período compreendido entre janeiro de 1999 e maio de 2000. O sistema agroflorestal contribuiu com 6,1 Mg ha-1 ano-1 de matéria seca de serrapilheira, no entanto o solteiro aportou 4,5 Mg ha-1 ano-1, ressaltando-se que esta última apresentou teor mais elevado de macronutrientes. O solo do sistema agroflorestal exibiu maior teor de umidade de 20-40 cm, maior capacidade de troca de cátions e soma de bases trocáveis, maior teor de K, Ca, Mg, Cu e Zn em ambos os horizontes do solo e menor índice de saturação de alumínio e alumínio trocável na camada mais profunda do que o solo sob a monocultura. No cultivo solteiro, o solo apresentou maior teor de P e de matéria orgânica, tanto na camada superficial quanto na profunda.<br>Coffee plants in agroforestry systems is an alternative to full sunlight cultivation, presenting the potential benefits of enhancing soil chemical and physical characteristics, reducing soil erosion, besides maintaining soil moisture for longer periods. This research aimed at comparing the quantity and nutrient concentration in the litter, soil fertility and soil moisture in coffee crops under full sunlight monocrop and in agroforestry systems, at the Zona da Mata, Minas Gerais, Brazil. The research was carried out between January 1999 and May 2000. The agroforestry system, contributed with 6.1 Mg ha-1 year-1 of litter dry matter while the monoculture produced 4.5 Mg ha-1 year-1, which presented higher nutrient content. The litter in monoculture presented higher nutrient content. The agroforestry system presented higher soil moisture content (20-40 cm depth) and K, Ca, Mg, Sum of Basis, Cation Exchange Capacity, Cu and Zn levels in both soil depth, besides lower aluminum saturation and Al values in deeper layer than soil of monocrop coffee. Soil under monoculture presented higher P and organic matter content than agroforestry system

Nutrientes foliares de espécies arbóreas de três estádios sucessionais de floresta ombrófila densa no sul do Brasil Leaf nutrient content of tree species from three successional stages of tropical rain forest in south Brazil

As concentrações de macro e micronutrientes foliares de espécies arbóreas foram avaliadas em três estádios sucessionais (inicial, intermediário e avançado) de uma floresta ombrófila densa das terras baixas, no litoral do Estado do Paraná, crescendo sobre solo arenoso e oligotrófico. Dentre as espécies arbóreas mais importantes de cada estádio sucessional (quatro iniciais; oito intermediárias; 11 avançadas), coletou-se folhas maduras de cinco diferentes indivíduos de cada estádio sucessional para a análise química dos seguintes elementos: N, P, K, Ca, Mg, C, Zn, Fe, Cu e Mn. As espécies do estádio inicial possuem as menores concentrações médias foliares de N, P, K, Zn, Fe e a maior concentração de Mg e estas concentrações são estatisticamente diferentes (p <0,05), quando comparadas com os valores médios dos demais estádios. Nos estádios intermediário e avançado, as concentrações médias de N, Ca e Mg, assim como os micronutrientes estão dentro dos valores esperados para florestas tropicais. As concentrações médias de K, nos estádios inicial e intermediário, e as concentrações médias de P, em todos os estádios, encontram-se abaixo dos valores reportados para as florestas tropicais. A relação C/N é alta (>25:1), apesar da tendência de diminuir à medida que avança a sucessão. O aumento da concentração da maioria dos nutrientes foliares analisados ao longo do gradiente sucessional está associado, possivelmente, com o incremento do acúmulo da serapilheira sobre o solo, o que proporciona ciclagem de nutrientes mais intensa e maiores concentrações de nutrientes no solo.<br>We investigated the leaf nutrient content of trees species from three distinct successional stages (early, intermediate, late) of a lowland rain forest located near the coast of Paraná State, Brazil. This forest grows on sandy soil with low nutrient content. We collected mature leaves from five different individuals of each sucessional stages of the most important tree species of each successional stage (four of the early; eight of the intermediate and 11 of the late stages) for chemical analysis of following elements: N, P, K, Ca, Mg, C, Zn, Fe, Cu e Mn. The species from early sucessional stage have lower contents of N, P, K, Zn, Fe, and higher contents of Mg. These concentrations are statistically different (p <0,05) when compared to mean values of the other stages. For the intermediate and late successional stages, the average nutrient concentrations of N, Ca, Mg and micronutrients are within the range of values expected for tropical forests. Foliar K concentration, from early and intermediate successional stages, and foliar P concentration, for all successional stages, are below the reported range of values for tropical forests. The C/N ratio is high (>25:1), despite of the tendency to decrease as succession advances. The increment of concentration of the most studied foliar nutrients along the successional gradient is probably related to the accumulation of litter above the soil that provides a more adequate environment for efficient nutrient cycling and higher nutrient concentration in the soil

Measurement of the tt¯ charge asymmetry in events with highly Lorentz-boosted top quarks in pp collisions at s=13 TeV

The measurement of the charge asymmetry in top quark pair events with highly Lorentz-boosted top quarks decaying to a single lepton and jets is presented. The analysis is performed using proton-proton collisions at s=13TeV with the CMS detector at the LHC and corresponding to an integrated luminosity of 138 fb−1. The selection is optimized for top quarks produced with large Lorentz boosts, resulting in nonisolated leptons and overlapping jets. The top quark charge asymmetry is measured for events with a tt¯ invariant mass larger than 750 GeV and corrected for detector and acceptance effects using a binned maximum likelihood fit. The measured top quark charge asymmetry of (0.42−0.69+0.64)% is in good agreement with the standard model prediction at next-to-next-to-leading order in quantum chromodynamic perturbation theory with next-to-leading-order electroweak corrections. The result is also presented for two invariant mass ranges, 750–900 and >900GeV

Search for new Higgs bosons via same-sign top quark pair production in association with a jet in proton-proton collisions at s=13TeV

A search is presented for new Higgs bosons in proton-proton (pp) collision events in which a same-sign top quark pair is produced in association with a jet, via the pp→tH/A→ttc‾ and pp→tH/A→ttu‾ processes. Here, H and A represent the extra scalar and pseudoscalar boson, respectively, of the second Higgs doublet in the generalized two-Higgs-doublet model (g2HDM). The search is based on pp collision data collected at a center-of-mass energy of 13 TeV with the CMS detector at the LHC, corresponding to an integrated luminosity of 138fb−1. Final states with a same-sign lepton pair in association with jets and missing transverse momentum are considered. New Higgs bosons in the 200–1000 GeV mass range and new Yukawa couplings between 0.1 and 1.0 are targeted in the search, for scenarios in which either H or A appear alone, or in which they coexist and interfere. No significant excess above the standard model prediction is observed. Exclusion limits are derived in the context of the g2HDM

Study of azimuthal anisotropy of ϒ(1S) mesons in pPb collisions at sNN = 8.16 TeV

The azimuthal anisotropy of Image 1 mesons in high-multiplicity proton-lead collisions is studied using data collected by the CMS experiment at a nucleon-nucleon center-of-mass energy of 8.16TeV. The Image 1 mesons are reconstructed using their dimuon decay channel. The anisotropy is characterized by the second Fourier harmonic coefficients, found using a two-particle correlation technique, in which the Image 1 mesons are correlated with charged hadrons. A large pseudorapidity gap is used to suppress short-range correlations. Nonflow contamination from the dijet background is removed using a low-multiplicity subtraction method, and the results are presented as a function of Image 1 transverse momentum. The azimuthal anisotropies are smaller than those found for charmonia in proton-lead collisions at the same collision energy, but are consistent with values found for Image 1 mesons in lead-lead interactions at a nucleon-nucleon center-of-mass energy of 5.02 TeV

Search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state in proton-proton collisions at s=13TeV

A search for new heavy resonances decaying to WW, WZ, ZZ, WH, or ZH boson pairs in the all-jets final state is presented. The analysis is based on proton-proton collision data recorded by the CMS detector in 2016–2018 at a centre-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 138fb−1. The search is sensitive to resonances with masses between 1.3 and 6TeV, decaying to bosons that are highly Lorentz-boosted such that each of the bosons forms a single large-radius jet. Machine learning techniques are employed to identify such jets. No significant excess over the estimated standard model background is observed. A maximum local significance of 3.6 standard deviations, corresponding to a global significance of 2.3 standard deviations, is observed at masses of 2.1 and 2.9 TeV. In a heavy vector triplet model, spin-1 Z′ and W′ resonances with masses below 4.8TeV are excluded at the 95% confidence level (CL). These limits are the most stringent to date. In a bulk graviton model, spin-2 gravitons and spin-0 radions with masses below 1.4 and 2.7TeV, respectively, are excluded at 95% CL. Production of heavy resonances through vector boson fusion is constrained with upper cross section limits at 95% CL as low as 0.1fb