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BACKGROUND: Robust data on the learning curve (LC) of transcatheter aortic valve replacement (TAVR) are lacking in developing countries. OBJECTIVE: To assess TAVR's LC in Brazil over time. METHODS: We analyzed data from the Brazilian TAVR registry from 2008 to 2023. Patients from each center were numbered chronologically in case sequence numbers (CSNs). LC was performed using restricted cubic splines adjusted for EuroSCORE-II and the use of new-generation prostheses. Also, in-hospital outcomes were compared between groups defined according to the level of experience based on the CSN: 1st to 40th (initial-experience), 41st to 80th (early-experience), 81st to 120th (intermediate-experience), and over 121st (high-experience). Additional analysis was performed grouping hospitals according to the number of cases treated before 2014 (>40 and ≤40 procedures). The level of significance adopted was <0.05. RESULTS: A total of 3,194 patients from 25 centers were included. Mean age and EuroSCORE II were 80.7±8.1 years and 7±7.1, respectively. LC analysis demonstrated a drop in adjusted in-hospital mortality after treating 40 patients. A leveling off of the curve was observed after case #118. In-hospital mortality across the groups was 8.6%, 7.7%, 5.9%, and 3.7% for initial-, early-, intermediate-, and high-experience, respectively (p<0.001). High experience independently predicted lower mortality (OR 0.57, p=0.013 vs. initial experience). Low-volume centers before 2014 showed no significant decrease in the likelihood of death with gained experience, whereas high-volume centers had a continuous improvement after case #10. CONCLUSION: A TAVR LC phenomenon was observed for in-hospital mortality in Brazil. This effect was more pronounced in centers that treated their first 40 cases before 2014 than those that reached this milestone after 2014.

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Resumo Fundamento Dados robustos sobre a curva de aprendizagem (LC) da substituição da válvula aórtica transcateter (TAVR) são escassos nos países em desenvolvimento. Objetivo Avaliar a LC da TAVR no Brasil ao longo do tempo. Métodos Analisamos dados do registro brasileiro de TAVR de 2008 a 2023. Pacientes de cada centro foram numerados cronologicamente em número sequencial de caso (NSC). A LC foi realizada usando um spline cúbico restrito ajustado para o EuroSCORE-II e o uso de próteses de nova geração. Ainda, os desfechos hospitalares foram comparados entre grupos definidos de acordo com o nível de experiência, com base no NSC: 1º ao 40º caso (experiência inicial), 41º ao 80º caso (experiência básica), 81º ao 120º caso (experiência intermediária) e 121º caso em diante (experiência alta). Análises adicionais foram conduzidas de acordo com o número de casos tratados antes de 2014 (>40 e ≤40 procedimentos). O nível de significância adotado foi p <0,05. Resultados Foram incluídos 3194 pacientes de 25 centros. A idade média foi 80,7±8,1 anos e o EuroSCORE II médio foi 7±7,1. A análise da LC demonstrou uma queda na mortalidade hospitalar ajustada após o tratamento de 40 pacientes. Um patamar de nivelamento na curva foi observado após o caso 118. A mortalidade hospitalar entre os grupos foi 8,6%, 7,7%, 5,9%, e 3,7% para experiência inicial, básica, intermediária e alta, respectivamente (p<0,001). A experiência alta foi preditora independente de mortalidade mais baixa (OR 0,57, p=0,013 vs. experiência inicial). Centros com baixo volume de casos antes de 2014 não mostraram uma redução significativa na probabilidade de morte com o ganho de experiência, enquanto centros com alto volume de casos antes de 2014 apresentaram uma melhora contínua após o caso de número 10. Conclusão Observou-se um fenômeno de LC para a mortalidade hospitalar do TAVR no Brasil. Esse efeito foi mais pronunciado em centros que trataram seus 40 primeiros casos antes de 2014 que naqueles que o fizeram após 2014.

Abstract Background Robust data on the learning curve (LC) of transcatheter aortic valve replacement (TAVR) are lacking in developing countries. Objective To assess TAVR's LC in Brazil over time. Methods We analyzed data from the Brazilian TAVR registry from 2008 to 2023. Patients from each center were numbered chronologically in case sequence numbers (CSNs). LC was performed using restricted cubic splines adjusted for EuroSCORE-II and the use of new-generation prostheses. Also, in-hospital outcomes were compared between groups defined according to the level of experience based on the CSN: 1st to 40th (initial-experience), 41st to 80th (early-experience), 81st to 120th (intermediate-experience), and over 121st (high-experience). Additional analysis was performed grouping hospitals according to the number of cases treated before 2014 (>40 and ≤40 procedures). The level of significance adopted was <0.05. Results A total of 3,194 patients from 25 centers were included. Mean age and EuroSCORE II were 80.7±8.1 years and 7±7.1, respectively. LC analysis demonstrated a drop in adjusted in-hospital mortality after treating 40 patients. A leveling off of the curve was observed after case #118. In-hospital mortality across the groups was 8.6%, 7.7%, 5.9%, and 3.7% for initial-, early-, intermediate-, and high-experience, respectively (p<0.001). High experience independently predicted lower mortality (OR 0.57, p=0.013 vs. initial experience). Low-volume centers before 2014 showed no significant decrease in the likelihood of death with gained experience, whereas high-volume centers had a continuous improvement after case #10. Conclusion A TAVR LC phenomenon was observed for in-hospital mortality in Brazil. This effect was more pronounced in centers that treated their first 40 cases before 2014 than those that reached this milestone after 2014.

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Coronary artery lesions related to pacemaker implantation are rare complications. With the increasing adoption of the technique of permanent transseptal pacing of the left bundle branch area pacing (LBBAP), an increase in the incidence of these complications may be expected. We report two cases of coronary lesions after permanent transeptal pacing of the LBBAP: the first with a small coronary artery fistula, and the second with an extrinsic coronary compression. Both complications occurred with stylet-driven pacing leads with extendable helix. In the first case, since the shunt volume was small and no major complications were reported, the patient was treated conservatively with good outcome. The second case required lead repositioning due to acute decompensated heart failure.

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INTRODUCTION: In patients treated with bare metal stents and earlygeneration drug-eluting stents (DES) smaller stent diameter (SD) has been associated with worse long-term outcomes after percutaneous coronary intervention (PCI). Data on the impact of small SD on outcomes after PCI with third generation DES is scarce. OBJECTIVE: The aim of this study was to evaluate the impact of SD on clinical outcomes, using a third generation sirolimus-eluting coronary stent with thin struts and abluminal biodegradable polymer. METHODS: Consecutive patients treated with Inspiron® (Scitech, Brazil) in native coronary arteries lesions between June 2017 and January 2022 were included, in a total of 25 Brazilian centers. Patients were grouped according to SD: 3.50mm. One-year event rates were estimated using the Kaplan-Meier method and adjusted hazard ratios were generated using Cox regression analysis. The primary endpoint was a composite of major adverse cardiovascular events (MACE) defined by the composite of cardiovascular death, myocardial infarction (MI) or target-lesion revascularization (TLR) at 12 months. RESULTS: Of the 2,803 patients who underwent PCI with Inspiron®, 24,5% (n = 688) had SD ≤2.50 mm, 45.0% (n = 1,263) had SD 2.75-3.00mm and 30,4% (n = 852) had SD >3.50 mm. At 1 year, MACE rates were 3.1%, 2.1% and 1.3%, respectively, with increasing SD (p = 0.054). Death due to CV causes at 12 months rates decreased with increasing SD (2.9%, 1.8% and 0.8%, respectively [p < 0.009]) whereas rates of MI related study device at 12 months across SD groups were comparable (0.0%, 0.5%, and 0.1%, respectively [p = 0.086]). After multivariate stepwise Cox regression, smaller SD remained associated with higher rates of MACE (HR 0.46, 95%CI of 0.241-0.890; p=0.022). As seen in Figure 1, the risk of MACE is significantly increased in the first 30 days and remain higher up to 12 months among individuals with mean vessel diameter <2.50mm. CONCLUSIONS: In a large cohort of patients undergoing PCI with third generation DES MACE rates were low, but still higher among patients with smaller SD, mainly drive by higher CV deaths at 12 months. Further research into the optimal treatment strategy of small coronary arteries is still warranted.

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INTRODUCTION: Inspiron® (Scitech, Brazil) is a 3rd generation drug eluting stent designed to create a fast and homogeneous endothelialization, possibly improving clinical outcomes. OBJECTIVES: The aim of this study was to evaluate the safety and efficacy of a sirolimus-eluting coronary stent, composed of a metallic chromium-cobalt platform with thin struts (75 µm), which releases sirolimus from a bioresorbable polymer applied only to the abluminal surface, in a real-world scenario, as a post-marketing clinical follow-up evaluation. METHODS: We pooled patient-level databases derived from the INSPIRION and LATITUDE prospective trials. Between June 2017 and January 2022, a total of 25 Brazilian centers included 2,803 patients that underwent percutaneous coronary intervention (PCI) in native coronary arteries lesions with Inspiron® (Scitech, Brazil) stent implantation. Exclusion criteria included target lesion located in saphenous vein or arterial graft, and use of coronary stent other than Inspiron® in the index procedure. The primary endpoint was a composite outcome of major adverse cardiovascular events (MACE) defined by the composite of cardiovascular death, myocardial infarction (MI) or target-lesion revascularization (TLR) at 12 months. The secondary outcomes included all-cause death, cardiovascular death, any MI, TLR, target-vessel revascularization (TVR), and probable and definite stent thrombosis at 12 months. RESULTS: The mean age was 62.0 ± 10.8 years, 36.5% had diabetes (12.7% on insulin), 17.6% had previous PCI and 54.9% presented with an acute coronary syndrome (ACS). At a median follow-up of 410 days, MACE occurred in 58 (2.1%) patients, all-cause death in 102 (3.6%), MI in 14 (0.5%), and target vessel revascularization in 2 (0.1%) patients. Definite or probable stent thrombosis occurred in 20 (0.7%) patients. CONCLUSIONS: The 1-year MACE rate, as well as the individual endpoint components, were low and consistent with previous results available for 3rd generation drug eluting stent. The result of this study demonstrates the safety and efficacy of this stent in a real-world population.

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BACKGROUND: There are limited real-world data on the clinical course of untreated coronary lesions according to their functional severity. OBJECTIVE: To evaluate the 5-year clinical outcomes of patients with revascularized lesions with fractional flow reserve (FFR) ≤ 0.8 and patients with non-revascularized lesions with FFR > 0.8. METHODS: The FFR assessment was performed in 218 patients followed for up to 5 years. Participants were classified based on FFR into ischemia group (≤ 0.8, intervention group, n = 55), low-normal FFR group (> 0.8-0.9, n = 91), and high-normal FFR group (> 0.9, n = 72). The primary endpoint was major adverse cardiac events (MACEs), a composite of death, myocardial infarction, and need for repeat revascularization. The significance level was set at 0.05; therefore, results with a p-value < 0.05 were considered statistically significant. RESULTS: Most patients were male (62.8%) with a mean age of 64.1 years. Diabetes was present in 27%. On coronary angiography, the severity of stenosis was 62% in the ischemia group, 56.4% in the low-normal FFR group, and 54.3% in the high-normal FFR group (p<0.05). Mean follow-up was 3.5 years. The incidence of MACEs was 25.5%, 13.2%, and 11.1%, respectively (p=0.037). MACE incidence did not differ significantly between the low-normal and high-normal FFR groups. CONCLUSION: Patients with FFR indicative of ischemia had poorer outcomes than those in non-ischemia groups. There was no difference in the incidence of events between the low-normal and high-normal FFR groups. Long-term studies with a large sample size are needed to better assess cardiovascular outcomes in patients with moderate coronary stenosis with FFR values between 0.8 and 1.0.

FUNDAMENTO: Existem dados limitados sobre a evolução clínica de lesões coronarianas não tratadas de acordo com sua gravidade funcional no mundo real. OBJETIVO: Este estudo teve como objetivo avaliar os resultados clínicos de até 5 anos em pacientes com lesões revascularizadas com reserva de fluxo fracionada (FFR) ≤ 0,8 e em pacientes com lesões não revascularizadas com FFR > 0,8. MÉTODOS: A avaliação pelo FFR foi realizada em 218 pacientes seguidos por até 5 anos. Os participantes foram classificados com base na FFR no grupo isquêmico (≤ 0,8, grupo intervenção, n = 55), no grupo FFR normal-baixa (> 0,8-0,9, n = 91) e no grupo FFR normal-alta (> 0,9, n = 72). O desfecho primário foram eventos cardíacos adversos maiores (ECAMs), um composto de morte, infarto do miocárdio e necessidade de nova revascularização. O nível de significância adotado neste estudo foi alfa = 0,05; deste modo, resultados com valores de p < 0,05 foram considerados estatisticamente significativos. RESULTADOS: A maioria dos participantes era do sexo masculino (62,8%) com média de idade de 64,1 anos. Diabetes estava presente em 27%. À angiografia coronariana, a gravidade da estenose avaliada foi de 62%, 56,4% e 54,3% nos grupos isquêmico, FFR normal-baixa e FFR normal-alta, respectivamente (p < 0,05). O período médio de acompanhamento foi de 3,5 anos. A incidência ECAM foi de 25,5%, 13,2% e 11,1%, respectivamente (p = 0,037). Não houve diferença na incidência de ECAM entre os grupos FFR normal-baixa e FFR normal-alta (p = NS). CONCLUSÃO: Pacientes com FFR indicativa de isquemia apresentaram piores desfechos quando comparados aos dos grupos não isquêmicos. Entre os grupos que apresentaram valores de FFR considerados normal-baixo e normal-alto, não houve diferença na incidência de eventos. Há necessidade de estudos de longo prazo e com grande número de pacientes para melhor avaliar os desfechos cardiovasculares em pacientes portadores de estenose coronariana moderada com valores de FFR entre 0,8 e 1,0.

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Resumo Fundamento Existem dados limitados sobre a evolução clínica de lesões coronarianas não tratadas de acordo com sua gravidade funcional no mundo real. Objetivo Este estudo teve como objetivo avaliar os resultados clínicos de até 5 anos em pacientes com lesões revascularizadas com reserva de fluxo fracionada (FFR) ≤ 0,8 e em pacientes com lesões não revascularizadas com FFR > 0,8. Métodos A avaliação pelo FFR foi realizada em 218 pacientes seguidos por até 5 anos. Os participantes foram classificados com base na FFR no grupo isquêmico (≤ 0,8, grupo intervenção, n = 55), no grupo FFR normal-baixa (> 0,8-0,9, n = 91) e no grupo FFR normal-alta (> 0,9, n = 72). O desfecho primário foram eventos cardíacos adversos maiores (ECAMs), um composto de morte, infarto do miocárdio e necessidade de nova revascularização. O nível de significância adotado neste estudo foi alfa = 0,05; deste modo, resultados com valores de p < 0,05 foram considerados estatisticamente significativos. Resultados A maioria dos participantes era do sexo masculino (62,8%) com média de idade de 64,1 anos. Diabetes estava presente em 27%. À angiografia coronariana, a gravidade da estenose avaliada foi de 62%, 56,4% e 54,3% nos grupos isquêmico, FFR normal-baixa e FFR normal-alta, respectivamente (p < 0,05). O período médio de acompanhamento foi de 3,5 anos. A incidência ECAM foi de 25,5%, 13,2% e 11,1%, respectivamente (p = 0,037). Não houve diferença na incidência de ECAM entre os grupos FFR normal-baixa e FFR normal-alta (p = NS). Conclusão Pacientes com FFR indicativa de isquemia apresentaram piores desfechos quando comparados aos dos grupos não isquêmicos. Entre os grupos que apresentaram valores de FFR considerados normal-baixo e normal-alto, não houve diferença na incidência de eventos. Há necessidade de estudos de longo prazo e com grande número de pacientes para melhor avaliar os desfechos cardiovasculares em pacientes portadores de estenose coronariana moderada com valores de FFR entre 0,8 e 1,0.

Abstract Background There are limited real-world data on the clinical course of untreated coronary lesions according to their functional severity. Objective To evaluate the 5-year clinical outcomes of patients with revascularized lesions with fractional flow reserve (FFR) ≤ 0.8 and patients with non-revascularized lesions with FFR > 0.8. Methods The FFR assessment was performed in 218 patients followed for up to 5 years. Participants were classified based on FFR into ischemia group (≤ 0.8, intervention group, n = 55), low-normal FFR group (> 0.8-0.9, n = 91), and high-normal FFR group (> 0.9, n = 72). The primary endpoint was major adverse cardiac events (MACEs), a composite of death, myocardial infarction, and need for repeat revascularization. The significance level was set at 0.05; therefore, results with a p-value < 0.05 were considered statistically significant. Results Most patients were male (62.8%) with a mean age of 64.1 years. Diabetes was present in 27%. On coronary angiography, the severity of stenosis was 62% in the ischemia group, 56.4% in the low-normal FFR group, and 54.3% in the high-normal FFR group (p<0.05). Mean follow-up was 3.5 years. The incidence of MACEs was 25.5%, 13.2%, and 11.1%, respectively (p=0.037). MACE incidence did not differ significantly between the low-normal and high-normal FFR groups. Conclusion Patients with FFR indicative of ischemia had poorer outcomes than those in non-ischemia groups. There was no difference in the incidence of events between the low-normal and high-normal FFR groups. Long-term studies with a large sample size are needed to better assess cardiovascular outcomes in patients with moderate coronary stenosis with FFR values between 0.8 and 1.0.

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Adaptation to climate change is a strategy for crops to cope with the scenario of rising temperatures worldwide. In the case of Coffea arabica L., the use of agroforestry systems (AFS) with woody species is a promising practice to reduce excessive heat during the day. This study aimed to 1) evaluate air temperature changes that occur in an AFS of coffee and double alleys of rubber trees (Hevea brasiliensis Müell. Arg.) and 2) carry out an analysis of future warming scenarios by comparing the cultivation of Arabic coffee in full sun and in an AFS of double alleys of rubber trees. The microclimatic variables were measured between two rows of coffee trees at 1.0 m of height from June 2016 to June 2018. The results indicate that the AFS with double alleys of rubber trees spaced 16 m apart had an average temperature reduction from 1.4 to 2.5 °C from 10h00 to 16h00. The study also simulated temperature increases of 1.7, 2.6, 3.1, and 4.8 °C from 2018 to 2099, according to scenarios predicted by the Intergovernmental Panel on Climate Change (IPCC), and the impact in coffee production in Paraná State, Brazil. Using the climatic generator PGECLIMA_R, simulations suggest a progressive reduction of traditional areas suitable for open-grown coffee in the state. Production conditions can be maintained through the AFS, since the systems attenuate mean temperatures by 1-2 °C. We conclude that the AFS of coffee and rubber trees contribute to coffee crop adaptations to a future warmer environment.

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AIMS: To evaluate whether a strategy of double-dose influenza vaccination during hospitalization for an acute coronary syndrome (ACS) compared with standard-dose outpatient vaccination (as recommended by current guidelines) would further reduce the risk of major cardiopulmonary events. METHODS AND RESULTS: Vaccination against Influenza to Prevent cardiovascular events after Acute Coronary Syndromes (VIP-ACS) was a pragmatic, randomized, multicentre, active-comparator, open-label trial with blinded outcome adjudication comparing two strategies of influenza vaccination following an ACS: double-dose quadrivalent inactivated vaccine before hospital discharge vs. standard-dose quadrivalent inactivated vaccine administered in the outpatient setting 30 days after randomization. The primary outcome was a hierarchical composite of all-cause death, myocardial infarction, stroke, unstable angina, hospitalization for heart failure, urgent coronary revascularization, and hospitalization for respiratory causes, analysed by the win ratio method. Patients were followed for 12 months. During two influenza seasons, 1801 participants were included at 25 centres in Brazil. The primary outcome was not different between groups, with 12.7% wins in-hospital double-dose vaccine group and 12.3% wins in the standard-dose vaccine group {win ratio: 1.02 [95% confidence interval (CI): 0.79-1.32], P = 0.84}. Results were consistent for the key secondary outcome, a hierarchical composite of cardiovascular death, myocardial infarction and stroke [win ratio: 0.94 (95% CI: 0.66-1.33), P = 0.72]. Time-to-first event analysis for the primary outcome showed results similar to those of the main analysis [hazard ratio 0.97 (95% CI: 0.75-1.24), P = 0.79]. Adverse events were infrequent and did not differ between groups. CONCLUSION: Among patients hospitalized with an ACS, double-dose influenza vaccination before discharge did not reduce cardiopulmonary outcomes compared with standard-dose vaccination in the outpatient setting. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov number: NCT04001504.

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BACKGROUND: Chronic kidney disease is commonly found in patients with aortic stenosis (AS) undergoing transcatheter aortic valve replacement (TAVR) and has marked impact in their prognosis. It has been shown however that TAVR may improve renal function by alleviating the hemodynamic barrier imposed by AS. Nevertheless, the predictors of and clinical consequences of renal function improvement are not well established. Our aim was to assess the predictors of improvement of renal function after TAVR. METHODS: The present work is an analysis of the Brazilian Registry of TAVR, a national non-randomized prospective study with 22 Brazilian centers. Patients with baseline renal dysfunction (estimated glomerular filtration rate [eGFR] < 60mL/min/1.73m2) were stratified according to renal function after TAVR: increase >10% in eGFR were classified as TAVR induced renal function improvement (TIRFI); decrease > 10% in eGFR were classified as acute kidney injury (AKI) and stable renal function (neither criteria). RESULTS: A total of 819 consecutive patients with symptomatic severe AS were included. Of these, baseline renal dysfunction (estimated glomerular filtration rate [eGFR] < 60mL/min/1.73m2) was present in 577 (70%) patients. Considering variance in renal function between baseline and at discharge after TAVR procedure, TIRFI was seen in 197 (34.1%) patients, AKI in 203 (35.2%), and stable renal function in 177 (30.7%). The independent predictors of TIRFI were: absence of coronary artery disease (OR: 0.69; 95% CI 0.48-0.98; P = 0.039) and lower baseline eGFR (OR: 0.98; 95% CI 0.97-1.00; P = 0.039). There was no significant difference in 30-day and 1-year all-cause mortality between patients with stable renal function or TIRFI. Nonetheless, individuals that had AKI after TAVR presented higher mortality compared with TIRFI and stable renal function groups (29.3% vs. 15.4% vs. 9.5%, respectively; p < 0.001). CONCLUSIONS: TIRFI was frequently found among baseline impaired renal function individuals but was not associated with improved 1-year outcomes.

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Land use and tillage practices may change soil structure and undermine sustainable agriculture; however, such changes are hardly identified in the short term. In this sense, agroforestry systems have been used to reduce soil degradation and promote sustainable production in coffee plantations. These areas are expected to have well-structured soils and hence improved root distribution. This study aimed to evaluate soil quality by the morphostructural and root distribution analyses comparing open-grown coffee and coffee in agroforestry systems with rubber trees for 19 years, in an Oxisol in northern Paraná State (Brazil). Treatments consisted of open-grown coffee (OG), coffee partially shaded by rubber trees (PSH), and coffee fully shaded by rubber trees (FSH). The mapping of morphostructural features and soil resistance to penetration in cultural profile walls identified changes in soil structure resulting from different tillage systems. Root distribution was better in coffee plants grown in PSH and FSH systems. At greater depths, cultural profiles of FSH and PSH showed a larger numbers of roots compared to OG. Among the three systems, PSH provided a better environment for root growth and distribution. This result could be attributed to the high biological activity and interaction between roots and aggregates in that profile. The FSH agroforestry system provided less compact morphological structures and more roots throughout the soil profile. The agroforestry systems presented fewer soil structural changes by tillage operations and lower values of soil penetration resistance. Coffee root distribution was an effective indicator of soil quality and consistent with the morphostructural characterization of cultural profile.(AU)

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Land use and tillage practices may change soil structure and undermine sustainable agriculture; however, such changes are hardly identified in the short term. In this sense, agroforestry systems have been used to reduce soil degradation and promote sustainable production in coffee plantations. These areas are expected to have well-structured soils and hence improved root distribution. This study aimed to evaluate soil quality by the morphostructural and root distribution analyses comparing open-grown coffee and coffee in agroforestry systems with rubber trees for 19 years, in an Oxisol in northern Paraná State (Brazil). Treatments consisted of open-grown coffee (OG), coffee partially shaded by rubber trees (PSH), and coffee fully shaded by rubber trees (FSH). The mapping of morphostructural features and soil resistance to penetration in cultural profile walls identified changes in soil structure resulting from different tillage systems. Root distribution was better in coffee plants grown in PSH and FSH systems. At greater depths, cultural profiles of FSH and PSH showed a larger numbers of roots compared to OG. Among the three systems, PSH provided a better environment for root growth and distribution. This result could be attributed to the high biological activity and interaction between roots and aggregates in that profile. The FSH agroforestry system provided less compact morphological structures and more roots throughout the soil profile. The agroforestry systems presented fewer soil structural changes by tillage operations and lower values of soil penetration resistance. Coffee root distribution was an effective indicator of soil quality and consistent with the morphostructural characterization of cultural profile.

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Thermal discomfort is one of the main causes of production losses in animals fully exposed to solar radiation under extensive livestock farming. The inclusion of trees in this farming system is the most efficient strategy to decrease the temperature and increase animal productivity without the need to explore new areas. In this context, the objective of this study was to characterize the microclimate in a silvopastoral system (SPS), a refuge area, and an open pasture, and evaluate thermal comfort and the ingestive behavior of animals under shade. The study was conducted at the Agronomic Institute of Paraná (IAPAR), located in Ibiporã, Paraná state, Brazil, in three areas with distinct management systems: a SPS of Eucalyptus grandis with Tifton 85 (Cynodon spp.), a woodland of Leucena leucocephala that provided shade to cattle, and a pasture in full sun (PFS). Automatic meteorological stations were installed in the SPS (one station beside the tree lines and the other in an average distance perpendicular to the rows), one in the refuge area, and one in the PFS. The measured variables were air temperature and relative humidity. The mean temperatures of the shaded treatments were compared to those of the PFS using a t-test. The mean values of the temperature and humidity index (THI) were calculated for each season of the year. The animal ingestion behavior in the SPS was analyzed in three typical days in different seasons of the year. Significant differences were observed between shade treatments and full-sun pasture, with a temperature decrease ranging from 0.4 to 1.6 °C in the shaded systems. The comparison of animal thermal comfort between the study areas in different seasons of the year indicated that there were no significant differences in thermal comfort between the SPS and refuge area relative to the PFS, suggesting a need to monitor the animals body temperature to better estimate thermal comfort. The evaluation of the ingestive behavior evidenced the...(AU)

O desconforto térmico é uma das principais causas da queda produtiva da pecuária extensiva a pleno sol, sendo a inserção de árvores no sistema a alternativa mais eficiente para atenuar a temperatura e aumentar a produtividade sem a necessidade de explorar novas áreas. Nesse contexto, objetivou-se caracterizar o microclima em um sistema silvipastoril, uma área de refúgio e a pleno sol, além de estimar o conforto térmico e avaliar o comportamento ingestivo dos animais sob sombra. O estudo foi realizado na estação experimental do Instituto Agronômico do Paraná (IAPAR), localizada em Ibiporã-PR, em três áreas com manejos distintos: um sistema silvipastoril, um bosque que serve como refúgio dos animais e uma pastagem a pleno sol. Foram instaladas estações meteorológicas automáticas no sistema silvipastoril, uma sob a sombra e outra na distância média perpendicular aos renques, na área de refúgio e no pasto a pleno sol. As variáveis medidas foram temperatura do ar e umidade relativa do ar. As temperaturas médias dos tratamentos arborizados foram comparadas com as do pasto a pleno sol por meio do test t. Valores médios de Temperatura e Índice de Umidade (ITU) foram calculados para cada estação do ano. Analisou-se o comportamento ingestivo animal no sistema silvipastoril em três dias representativos de diferentes estações do ano. Constatou-se diferenças significativas entre os tratamentos sombreados e a pastagem a pleno sol, com redução de temperatura variando entre 0,4 a 1,6 °C nos sistemas sombreados. Ao comparar o conforto térmico animal para as estações do ano, não verificou-se diferenças entre o sistema silvipastoril e refúgio em relação ao pleno sol, sendo indicado monitorar a temperatura corporal animal para melhor estimar sua condição de conforto térmico. Entretanto, ao avaliar o comportamento ingestivo animal evidenciou-se a preferência dos animais por realizar suas atividades sob a sombra das árvores; o sistema silvipastoril propiciou mudanças no seu...(AU)

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Thermal discomfort is one of the main causes of production losses in animals fully exposed to solar radiation under extensive livestock farming. The inclusion of trees in this farming system is the most efficient strategy to decrease the temperature and increase animal productivity without the need to explore new areas. In this context, the objective of this study was to characterize the microclimate in a silvopastoral system (SPS), a refuge area, and an open pasture, and evaluate thermal comfort and the ingestive behavior of animals under shade. The study was conducted at the Agronomic Institute of Paraná (IAPAR), located in Ibiporã, Paraná state, Brazil, in three areas with distinct management systems: a SPS of Eucalyptus grandis with Tifton 85 (Cynodon spp.), a woodland of Leucena leucocephala that provided shade to cattle, and a pasture in full sun (PFS). Automatic meteorological stations were installed in the SPS (one station beside the tree lines and the other in an average distance perpendicular to the rows), one in the refuge area, and one in the PFS. The measured variables were air temperature and relative humidity. The mean temperatures of the shaded treatments were compared to those of the PFS using a t-test. The mean values of the temperature and humidity index (THI) were calculated for each season of the year. The animal ingestion behavior in the SPS was analyzed in three typical days in different seasons of the year. Significant differences were observed between shade treatments and full-sun pasture, with a temperature decrease ranging from 0.4 to 1.6 °C in the shaded systems. The comparison of animal thermal comfort between the study areas in different seasons of the year indicated that there were no significant differences in thermal comfort between the SPS and refuge area relative to the PFS, suggesting a need to monitor the animals’ body temperature to better estimate thermal comfort. The evaluation of the ingestive behavior evidenced the...

O desconforto térmico é uma das principais causas da queda produtiva da pecuária extensiva a pleno sol, sendo a inserção de árvores no sistema a alternativa mais eficiente para atenuar a temperatura e aumentar a produtividade sem a necessidade de explorar novas áreas. Nesse contexto, objetivou-se caracterizar o microclima em um sistema silvipastoril, uma área de refúgio e a pleno sol, além de estimar o conforto térmico e avaliar o comportamento ingestivo dos animais sob sombra. O estudo foi realizado na estação experimental do Instituto Agronômico do Paraná (IAPAR), localizada em Ibiporã-PR, em três áreas com manejos distintos: um sistema silvipastoril, um bosque que serve como refúgio dos animais e uma pastagem a pleno sol. Foram instaladas estações meteorológicas automáticas no sistema silvipastoril, uma sob a sombra e outra na distância média perpendicular aos renques, na área de refúgio e no pasto a pleno sol. As variáveis medidas foram temperatura do ar e umidade relativa do ar. As temperaturas médias dos tratamentos arborizados foram comparadas com as do pasto a pleno sol por meio do test t. Valores médios de Temperatura e Índice de Umidade (ITU) foram calculados para cada estação do ano. Analisou-se o comportamento ingestivo animal no sistema silvipastoril em três dias representativos de diferentes estações do ano. Constatou-se diferenças significativas entre os tratamentos sombreados e a pastagem a pleno sol, com redução de temperatura variando entre 0,4 a 1,6 °C nos sistemas sombreados. Ao comparar o conforto térmico animal para as estações do ano, não verificou-se diferenças entre o sistema silvipastoril e refúgio em relação ao pleno sol, sendo indicado monitorar a temperatura corporal animal para melhor estimar sua condição de conforto térmico. Entretanto, ao avaliar o comportamento ingestivo animal evidenciou-se a preferência dos animais por realizar suas atividades sob a sombra das árvores; o sistema silvipastoril propiciou mudanças no seu...

Assuntos

RESUMO

A phenomenon called thermal inversion, in which there is the accumulation of colder and denser air in the layers closer to the soil, occurs in radiative frost nights, resulting in a temperature gradient with differences between the meteorological screen and grass, which vary depending on cooling conditions. Knowing this temperature difference assists in taking preventive measures against radiative frosts, as well as in estimating the probability of their occurrences. In this context, this study aimed to verify the adjustment of different probability distributions to determine the differences between the minimum temperature measured in the meteorological screen and grass temperature below 0 C for eight regions of the Paraná State, as well as the probability of occurring these differences and adjust estimation equations of grass temperature from minimum air temperature. Temperature differences between the screen and grass were calculated and probability distributions of their occurrences were adjusted in order to determine risks per intervals of temperature differences. Estimation equations of grass temperature were adjusted from minimum screen temperatures. Average gradients of minimum temperature were observed between the screen and grass ranging from 4.2 to 6.3 C in the analyzed regions. The average temperature difference measured in the meteorological screen and grass for the Paraná State was 5 °C. The probabilistic model of normal distribution is the most suitable for determining the probability of occurring the differences between the screen and grass temperatures for the Paraná State. Regional relief and climate conditions influence the magnitude of the minimum temperature gradient measured in the meteorological screen and grass.(AU)

Em noites de geada de radiação ocorre um fenômeno denominado de inversão térmica, em que há o acúmulo do ar mais frio e denso nas camadas de ar mais próximas ao solo. Isto resulta em um gradiente de temperatura, com diferenças entre o abrigo meteorológico e a relva que variam dependendo das condições de resfriamento. Conhecer essa diferença de temperatura auxilia na tomada de medidas preventivas contra as geadas de radiação, assim como na estimativa da probabilidade de ocorrência. Neste contexto, o objetivo desse trabalho foi verificar o ajuste de diferentes distribuições de probabilidade para determinar a diferença entre a temperatura mínima medida no abrigo meteorológico e a temperatura de relva abaixo de 0C para oito regiões do Estado do Paraná, bem como a probabilidade de ocorrência das diferenças e ajustar equações de estimativa da temperatura de relva a partir da temperatura mínima do ar. Foram calculadas as diferenças de temperatura entre o abrigo e a relva e posteriormente foram ajustadas distribuições de probabilidade de ocorrência das diferenças, com a finalidade de determinar os riscos por intervalos de diferenças de temperatura. E, por fim, foram ajustadas equações de estimativa da temperatura de relva a partir da temperatura mínima de abrigo. Foram constatados gradientes médios de temperatura mínima entre o abrigo e a relva variando de 4,2 a 6,3°C nas regiões analisadas. A diferença média de temperatura medida no abrigo meteorológico e a relva para o Estado do Paraná foi de 5°C. O modelo probabilístico de distribuição Normal é o mais indicado para a determinação da probabilidade de ocorrência das diferenças entre a temperatura de abrigo e de relva para o Estado do Paraná. As condições de relevo e clima regionais influenciam na magnitude do gradiente de temperatura mínima medida no abrigo meteorológico e na relva.(AU)

RESUMO

The occurrence of frost in southern and southeastern Brazil affects pasture quality and limits the use of forage species with high yield potential. Therefore, elucidating the cold tolerance of individual forage species could facilitate the selection of species that will optimize production and animal feeding throughout the year. Accordingly, the aim of the present study was to evaluate the cold tolerance of forage species to low temperatures, based on cell membrane stability and photoinhibition. Alfalfa (Medicago sativa), sorghum (Sorghum bicolor), black oat (Avena strigosa), marandu grass (Urochloa brizantha), pearl millet (Pennisetum americanum), mombaça grass (Megathyrsus maximus), and bermuda grass ‘Tifton 85 (Cynodon spp) plants were subjected to temperatures of 0.2, -0.9, -1.8, -2.7, -4.1, -4.6, and -6.2 °C for 1 h in a growth chamber. Cell membrane stability and photoinhibition were based on the electrical conductivity of leaf section solutions and chlorophyll fluorescence, respectively. Initial cold damage corresponded to a sudden increase in leaf solution conductivity and decrease in fluorescence. Millet and sorghum were able to tolerate exposure to temperatures as low as -2.7 °C, whereas black oat, marandu grass, alfafa, and mombaça grass were able to tolerate exposure to -4.1 °C, and bermuda grass ‘Tifton 85 was able to withstand temperatures below -6.2 °C.(AU)

A ocorrência de geadas no Sudeste e Sul do Brasil afeta a qualidade das pastagens e limita o uso de espécies com elevado potencial produtivo. O conhecimento da tolerância das forrageiras ao estresse por baixa temperatura contribui para a seleção das melhores espécies a serem utilizadas, levando à otimização de sua produção e garantindo o pastejo dos animais o ano inteiro. Assim, o objetivo deste trabalho foi avaliar a tolerância de espécies forrageiras às temperaturas baixas pela estabilidade da membrana celular e fotoinibição após o estresse por frio. Foram analisadas as forrageiras: alfafa (Medicago sativa), sorgo (Sorghum bicolor), aveia-preta (Avena strigosa), capim-marandu (Urochloa brizantha), milheto (Pennisetum americanum), capim-mombaça (Megathyrsus maximus) e Tifton 85 (Cynodon spp). As plantas foram submetidas às temperaturas de 0,2; -0,9; -1,8; -2,7; -4,1; -4,6 e -6,2 °C, durante uma hora, no interior de câmara de crescimento com condições de luminosidade e temperatura controladas, e avaliadas por meio do teste de condutividade elétrica da solução de secções foliares e fluorescência. O início dos danos correspondeu a um aumento súbito na condutividade elétrica da solução e diminuição na fluorescência. A tolerância das espécies forrageiras ao frio foi até a temperatura -2,7°C para milheto e sorgo; -4,1°C para alfafa, aveia-preta, Marandu e Mombaça, e inferior a -6,2°C para o Tifton 85.(AU)

Assuntos

RESUMO

The occurrence of frost in southern and southeastern Brazil affects pasture quality and limits the use of forage species with high yield potential. Therefore, elucidating the cold tolerance of individual forage species could facilitate the selection of species that will optimize production and animal feeding throughout the year. Accordingly, the aim of the present study was to evaluate the cold tolerance of forage species to low temperatures, based on cell membrane stability and photoinhibition. Alfalfa (Medicago sativa), sorghum (Sorghum bicolor), black oat (Avena strigosa), marandu grass (Urochloa brizantha), pearl millet (Pennisetum americanum), mombaça grass (Megathyrsus maximus), and bermuda grass ‘Tifton 85’ (Cynodon spp) plants were subjected to temperatures of 0.2, -0.9, -1.8, -2.7, -4.1, -4.6, and -6.2 °C for 1 h in a growth chamber. Cell membrane stability and photoinhibition were based on the electrical conductivity of leaf section solutions and chlorophyll fluorescence, respectively. Initial cold damage corresponded to a sudden increase in leaf solution conductivity and decrease in fluorescence. Millet and sorghum were able to tolerate exposure to temperatures as low as -2.7 °C, whereas black oat, marandu grass, alfafa, and mombaça grass were able to tolerate exposure to -4.1 °C, and bermuda grass ‘Tifton 85’ was able to withstand temperatures below -6.2 °C.

A ocorrência de geadas no Sudeste e Sul do Brasil afeta a qualidade das pastagens e limita o uso de espécies com elevado potencial produtivo. O conhecimento da tolerância das forrageiras ao estresse por baixa temperatura contribui para a seleção das melhores espécies a serem utilizadas, levando à otimização de sua produção e garantindo o pastejo dos animais o ano inteiro. Assim, o objetivo deste trabalho foi avaliar a tolerância de espécies forrageiras às temperaturas baixas pela estabilidade da membrana celular e fotoinibição após o estresse por frio. Foram analisadas as forrageiras: alfafa (Medicago sativa), sorgo (Sorghum bicolor), aveia-preta (Avena strigosa), capim-marandu (Urochloa brizantha), milheto (Pennisetum americanum), capim-mombaça (Megathyrsus maximus) e Tifton 85 (Cynodon spp). As plantas foram submetidas às temperaturas de 0,2; -0,9; -1,8; -2,7; -4,1; -4,6 e -6,2 °C, durante uma hora, no interior de câmara de crescimento com condições de luminosidade e temperatura controladas, e avaliadas por meio do teste de condutividade elétrica da solução de secções foliares e fluorescência. O início dos danos correspondeu a um aumento súbito na condutividade elétrica da solução e diminuição na fluorescência. A tolerância das espécies forrageiras ao frio foi até a temperatura -2,7°C para milheto e sorgo; -4,1°C para alfafa, aveia-preta, Marandu e Mombaça, e inferior a -6,2°C para o Tifton 85.

Assuntos

RESUMO

A phenomenon called thermal inversion, in which there is the accumulation of colder and denser air in the layers closer to the soil, occurs in radiative frost nights, resulting in a temperature gradient with differences between the meteorological screen and grass, which vary depending on cooling conditions. Knowing this temperature difference assists in taking preventive measures against radiative frosts, as well as in estimating the probability of their occurrences. In this context, this study aimed to verify the adjustment of different probability distributions to determine the differences between the minimum temperature measured in the meteorological screen and grass temperature below 0 C for eight regions of the Paraná State, as well as the probability of occurring these differences and adjust estimation equations of grass temperature from minimum air temperature. Temperature differences between the screen and grass were calculated and probability distributions of their occurrences were adjusted in order to determine risks per intervals of temperature differences. Estimation equations of grass temperature were adjusted from minimum screen temperatures. Average gradients of minimum temperature were observed between the screen and grass ranging from 4.2 to 6.3 C in the analyzed regions. The average temperature difference measured in the meteorological screen and grass for the Paraná State was 5 °C. The probabilistic model of normal distribution is the most suitable for determining the probability of occurring the differences between the screen and grass temperatures for the Paraná State. Regional relief and climate conditions influence the magnitude of the minimum temperature gradient measured in the meteorological screen and grass.

Em noites de geada de radiação ocorre um fenômeno denominado de inversão térmica, em que há o acúmulo do ar mais frio e denso nas camadas de ar mais próximas ao solo. Isto resulta em um gradiente de temperatura, com diferenças entre o abrigo meteorológico e a relva que variam dependendo das condições de resfriamento. Conhecer essa diferença de temperatura auxilia na tomada de medidas preventivas contra as geadas de radiação, assim como na estimativa da probabilidade de ocorrência. Neste contexto, o objetivo desse trabalho foi verificar o ajuste de diferentes distribuições de probabilidade para determinar a diferença entre a temperatura mínima medida no abrigo meteorológico e a temperatura de relva abaixo de 0C para oito regiões do Estado do Paraná, bem como a probabilidade de ocorrência das diferenças e ajustar equações de estimativa da temperatura de relva a partir da temperatura mínima do ar. Foram calculadas as diferenças de temperatura entre o abrigo e a relva e posteriormente foram ajustadas distribuições de probabilidade de ocorrência das diferenças, com a finalidade de determinar os riscos por intervalos de diferenças de temperatura. E, por fim, foram ajustadas equações de estimativa da temperatura de relva a partir da temperatura mínima de abrigo. Foram constatados gradientes médios de temperatura mínima entre o abrigo e a relva variando de 4,2 a 6,3°C nas regiões analisadas. A diferença média de temperatura medida no abrigo meteorológico e a relva para o Estado do Paraná foi de 5°C. O modelo probabilístico de distribuição Normal é o mais indicado para a determinação da probabilidade de ocorrência das diferenças entre a temperatura de abrigo e de relva para o Estado do Paraná. As condições de relevo e clima regionais influenciam na magnitude do gradiente de temperatura mínima medida no abrigo meteorológico e na relva.