Protective effect of bronchial challenge with hypertonic saline on nocturnal asthma

Inhalation of hypertonic saline (HS) causes bronchoconstriction in asthmatic subjects. Repeated inhalation of HS leads to substantially reduced bronchoconstriction, known as the refractory period. Refractoriness due to different stimuli has also been described (cross-refractoriness). Nocturnal asthma is defined as an increase in symptoms, need for medication, airway responsiveness, and/or worsening of lung function that usually occurs from 4 to 6 am. Our objective was to determine the effect of refractoriness on nocturnal asthma. The challenge test consisted of inhalations of 4.5% saline with increasing durations until a reduction of 20% in forced expiratory volume in 1 s (FEV1) (PD20HS) or total time of 15.5 min. Twelve subjects with nocturnal asthma were challenged with HS at 16:00 and 18:00 h and FEV1 was measured at 4:00 h. One to 2 weeks later, FEV1 was determined at 16:00 and 4:00 h. LogPD20HS at 18:00 h was significantly greater than logPD20HS at 16:00 h, 0.51 ± 0.50 and 0.69 ± 0.60 mg, respectively (P = 0.0033). When subjects underwent two HS challenges in the afternoon, mean (± SD) FEV1 reduction was 206 ± 414 mL or 9.81 ± 17.42%. On the control day (without challenge in the afternoon) FEV1 reduction was 523 ± 308 mL or 22.75 ± 15.40% (P = 0.021). Baseline FEV1 values did not differ significantly between the control and study days, 2.48 ± 0.62 and 2.36 ± 0.46 L, respectively. The refractory period following HS challenges reduces the nocturnal worsening of asthma. This new concept may provide beneficial applications to asthmatic patients

Spectral behavior of some modal soil profiles from São Paulo State, Brazil.

O sensoriamento remoto representa um importante potencial na avaliação do ambiente, contudo, ainda existe a necessidade de entender melhor as relações entre atributos do solo e dados espectrais. O objetivo do trabalho foi analisar descritivamente o comportamento espectral de alguns perfis de solos da região de Piracicaba, Estado de São Paulo, utilizando o espectrorradiômetro de laboratório (400 a 2500 nm). Procurou-se ainda, avaliar as relações entre energia eletromagnética refletida com atributos químicos, físicos e mineralógicos dos solos, verificando as variações espectrais das amostras ao longo dos perfis e suas relações com classificação e discriminação dos solos. Observou-se que solos mais arenosos refletiram mais, com curvas espectrais de aspecto ascendente, ao contrário dos solos argilosos. A banda centrada em 1900 nm discriminou solos com mineralogia 2:1 dos de 1:1 e oxídicos. Foi possível detectar a presença de caulinita, gibbsita e dos óxidos de ferro (hematita e goethita) presentes nos solos pelos aspectos descritivos das curvas, feições de absorção e intensidade de reflectância; e que existe uma relação entre níveis de intemperismo e informações espectrais. A avaliação dos dados espectrais de amostras dos horizontes superficiais e subsuperficiais permitiu caracterizar e discernir a variabilidade analítica do perfil, auxiliando na discriminação e classificação dos solos

Sustainable Intensification in Crop-Livestock Systems

Extensive livestock production is the main animal source food system in the Pampas and Campos sub-regions in South America. Beef cattle and sheep convert forage biomass that humans cannot eat into nutrient-dense human-edible foods (meat and milk) and valuable co-products (wool). However, diverse global pressures are acting on Pampas systems including increasing demand for protein sources (food security), climate change, environmental footprint, and competition for land. The integration of small areas of pasture-crop rotations is an alternative for increasing efficiency and sustainable intensification of agroecosystems based on natural grasslands. Rotations led by improved pastures increase the carrying capacity and productivity of traditional Pampas systems, and include crop production (soybean, rice) as an opportunity for farm diversification and resilience. Therefore, mixed crop-livestock systems can feed more people in terms of calories and protein than what is possible with specialized systems. The higher carrying capacity in the area under the rotation may allow less intensive grazing management in larger areas of native grasslands reducing threats to biodiversity. Some of the integrated management practices in crop-livestock systems are perennial pastures to mitigate soil organic carbon losses during cropping, biological nitrogen fixation by legumes, grazing cover crops, crop residue grazing, dual-purpose crops, and harvesting grain and hay for livestock feed. Also, complementary crop and livestock production systems facilitate more efficient nutrient cycling and self-sufficient systems promoting the circular economy concept as a strategic approach toward system sustainability. Key to understanding the potential of mixed crop-livestock systems are productive, environmental, economic, and social factors that determine their performance, as well as trade-offs among them. Development, implementation, maintenance, and analysis of long-term crop-livestock platforms research provides science-based information to address complex biological systems, and to implement innovative public policies at national scale to regulate soil use and to prevent non-sustainable agricultural practices