Effect of simulated extreme rainfall on the vegetative phenology of perennial and annual herbaceous plants from a Brazilian dry forest.

Detecting changes in the phenological responses of herbaceous species as a function of predicted climate change is important for forecasting future scenarios for the functioning of dry tropical forests, especially when predicting an increase in the frequency and intensity of extreme droughts. Because of the sensitivity of plants to water availability, our study hypothesizes that if years become drier or wetter, herbaceous plants will synchronously change the onset, duration, and intensity of their vegetative phenophases. We used a historical series of 60 years of precipitation observations for the Caatinga vegetation to define daily average of precipitation for rainy (Twet), median (Tcontrol), and dry (Tdry) years. We simulated past average daily rainfall (Twet, Tcontrol, and Tdry) while growing two herbaceous perennials and two herbaceous annuals. We monitored plant growth and measured the activity (absence or presence) and intensity of vegetative phenophases. We used circular statistical analysis to assess differences between treatments. Our results revealed that leaf production was seasonal but relatively uniform for perennial species and highly seasonal (wet season) for annual species. Simulated dry years induced lower leaf emergence concentrated over a few months in annual species, but this effect was more strongly significant in one of the two perennial species. Both annual and perennial species can experience delayed and less intense leaf abscission during the rainy season in years with below-average precipitation. In contrast, large voluminous rains in years with above-average precipitation can accelerate and intensify the process of leaf renewal. If future precipitation reductions occur, the changes in phenological response indicate that the cover of annual and perennial herbaceous species in this study will likely decrease, altering the landscape and functioning of dry tropical forests. However, the potential trade-offs observed may help populations of these species to persist during years of severe drought in the Caatinga.

Active biodegradable films produced with blends of rice flour and poly(butylene adipate co-terephthalate): effect of potassium sorbate on film characteristics.

The objective of work was to produce and characterize biodegradable films from rice flour, poly(butylene adipate co-terephthalate) (PBAT), glycerol and potassium sorbate, for application as active packaging for fresh lasagna pasta. The films were evaluated with respect to their optical, water vapor barrier, mechanical and microstructural properties. The mechanical properties and microstructure were evaluated after use as packaging material for fresh pasta for 45 days at 7°C. The blends of rice flour, PBAT, glycerol and potassium sorbate showed good processability and allowed for the pilot scale production of films by blow extrusion process. The addition of 1 to 5% potassium sorbate as plasticizer agent of films in place of glycerol did not alter the film mechanical properties and a sorbate concentration greater or equal than 3% reduced the opacity, although increasing the water vapor permeability. The films could be used as active packaging for fresh food pasta, since they remained integral and easy to handle after application. The rice flour was shown to be an excellent material for the formulation of biodegradable films, since it is a low-cost raw material from a renewable source. The addition of potassium sorbate did not affect the extrusion process, and could be used in the production of packaging for use with foods.

[Current complications of heart catheterization. Analysis of 100 cases]. / Complicações atuais do cateterismo cardíaco. Análise de 1000 pacientes.

PURPOSE: To analyse the impact of the new cardiac catheterization techniques on the complication profile of these procedures. PATIENTS AND METHODS: One thousand consecutive patients who underwent cardiac catheterization from August through December, 1989 (739 diagnostic and 201 therapeutic procedures), who were followed up until hospital discharge. Complications were classified accordingly to their type and severity, and were related to the procedure employed and to the left ventricular ejection fraction. RESULTS: There were no complications in 77.7% of the population studied. In the remaining 236 patients the incidence of mild, moderate and severe complications were, respectively: 11.2%, 7.3% and 3.8%. Severe vascular complications occurred in 0.5%, cardiac perforation requiring emergency surgical repair in 0.1%, severe arrhythmias in 1.4%, acute myocardial infarction in 0.4%, acute pulmonary edema in 0.3% and fatal events in 0.5% patients. CONCLUSION: Despite the increasing application of interventional techniques and the greater number of acutely ill patients referred to cardiac catheterization, these procedures have proved to be safe with a low complication rate.