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Summary: Variation in canopy water content (CWC) that can be detected from microwave remote sensing of vegetation optical depth (VOD) has been proposed as an important measure of vegetation water stress. However, the contribution of leaf surface water (LWs), arising from dew formation and rainfall interception, to CWC is largely unknown, particularly in tropical forests and other high‐humidity ecosystems.We compared VOD data from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR‐E) and CWC predicted by a plant hydrodynamics model at four tropical sites in Brazil spanning a rainfall gradient. We assessed how LWs influenced the relationship between VOD and CWC.The analysis indicates that while CWC is strongly correlated with VOD (R2 = 0.62 across all sites), LWs accounts for 61–76% of the diurnal variation in CWC despite being < 10% of CWC. Ignoring LWs weakens the near‐linear relationship between CWC and VOD and reduces the consistency in diurnal variation. The contribution of LWs to CWC variation, however, decreases at longer, seasonal to inter‐annual, time scales.Our results demonstrate that diurnal patterns of dew formation and rainfall interception can be an important driver of diurnal variation in CWC and VOD over tropical ecosystems and therefore should be accounted for when inferring plant diurnal water stress from VOD measurements. See also the Commentary on this article by Gerlien‐Safdi, 231: 5–7. [ABSTRACT FROM AUTHOR]

Abstract: Two Stegomastodon waringi teeth from Brazilian northeastern megafauna were dated by electron spin resonance (ESR) spectroscopy. The samples were collected in Pernambuco state, Brazil. The dating of these samples will contribute to the better knowledge of megafauna presence in this region as well as to the events associated to the extinction of these species. Additive dose method was used to evaluate the archeological dose (AD) and a non-linear relation between ESR signal amplitude and dose was obtained. The AD obtained by the exponential fitting was and , leading to an estimation of an age of and for radioisotope early uptake model, and for linear uptake and for a combination of uptake processes. [Copyright &y& Elsevier]

Abstract: Irradiation of foodstuff is a well-known food preservation technique. In Brazil spices are already irradiated for sanitary and preservation reasons. Chicken meat is an important commodity; Brazil is the second largest world producer and the largest world exporter. The shelf-life of chicken meat is limited by the presence of micro-organisms and enzyme activity and together with other preservation techniques irradiation seems to be an attractive option. In this study the dose delivered to frozen chicken cuts was measured and compared with the prescribed value. Chicken breast cuts were analyzed for 39 days for their microbiological activity, chemical and organoleptic properties. Cylindrical dosimeters were prepared using the weight composition of 80% of DL-alanine (Sigma Co), used without any further treatment except drying, and 20% of paraffin. The dosimeters having 4.7mm diameter and 12mm length were inserted in a build-up cap. Dosimeters were placed inside cardboard boxes containing frozen chicken breast cuts, packed in styrofoam trays wrapped with plastic film. The boxes were irradiated in an industrial 60Co irradiator (Nordion JS 7500) with a dose rate of 4kGy/h. First derivative ESR signals were obtained in a VARIAN E-4 spectrometer operating at X-band and equipped with a rectangular cavity (TE-102, model E-231). The cavity was constantly purged with dry nitrogen and modulated at 100KHz with 0.5mT peak to peak. A calibration curve was made for a few dosimeters from the same batch and used to obtain the dose from the ESR signal intensity. A batch of six boxes was irradiated at each experiment with prescribed doses of 1.5, 3.0 and 7.0kGy. Considering that the larger the radiation dose the greater is the probability of finding a product with its sensorial characteristics altered (odor of burned meat), we conclude that a dose of 3kGy would be more adequate, taking into account the microbiological and sensorial aspects. [Copyright &y& Elsevier]