2,405 research outputs found
Dynamics of soil and canopy temperature: a conceptual approach for Alentejo vineyards
Context and purpose of the study - Climate change imposes increasing restrictions and risks to
Mediterranean viticulture. Extreme heat and drought stress events are becoming more frequent which puts
in risk sustainability of Mediterranean viticulture. Moreover row crops e.g. grapevine for wine, are
increasingly prone to the impact of more intense/longer exposure time to heat stress. The amplified effects
of soil surface energy reflectance and conductance on soil-atmosphere heat fluxes can be harmful for leaf
and berry physiology. Leaf/canopy temperature is a biophysical variable with both physiological and
agronomic meaning. Improved comprehension of spatial and temporal dynamics of soil and leaf/canopy
temperature (thermal microclimate) in irrigated vineyards can support improved crop and soil monitoring
and management under more extreme and erratic climate conditions. In this work we propose a conceptual
approach to integrate information on major soil-vine-atmosphere interactions under deficit irrigation.
Ultimately a conceptual model based on temperature relations is proposed to support assessment of the
impact of air and soil temperatures on canopy and berry temperatures, leaf senescence and gas exchange.
This model may support Decision Support Systems (DSS) for canopy and soil management and irrigation
scheduling in Mediterranean vineyards. In addition a set of temperatures (e.g. canopy, soil) are proposed to
feed the conceptual models to support the DSSinfo:eu-repo/semantics/publishedVersio
Using soil and canopy temperature to support efficient management of irrigated vineyards
Extreme heat and drought events are becoming more frequent and erratic in Mediterranean Europe. Better
comprehension of spatial and temporal dynamics of heat fluxes and thermal microclimate in vineyards can support
vineyard’s management and minimize the impact of climate variability. Field experiments were carried out in South
Portugal with two red cvs. Touriga Nacional and Aragonez (syn. Tempranillo) under deficit irrigation. Canopy temperature
(Tc) is a robust predictor of plant water status, especially when measured under more stressful conditions. In parallel, soil
temperature (TS) had a positive influence on TC especially at the cluster zoneinfo:eu-repo/semantics/publishedVersio
Canopy and soil thermal patterns to support management of irrigated vineyards
Irrigated viticulture expanded fast in Southern European countries such as Portugal to optimize berry yield and quality and to increase vine’s longevity. However, intensive irrigation increases pressure over the local and regional water resources, that are getting scarcer, and increases also management costs. Additionally, row crops such as grapevine, are more vulnerable to heat stress due to the additional effects of soil heat fluxes which can negatively influence canopy and berry thermal condition. Therefore, a better understanding of grapevine responses (diurnal and seasonal) to environmental factors (air temperature, soil water) and agronomic practices (deficit irrigation, soil management) are on demand by the industry.
Ground based thermography was used to monitor the vertical profile of canopy temperature as well as soil temperature patterns along the day and season as means to assess plant water status and predict risks of heat stress damage. As part of the EU-INNOVINE project, field trials were carried in 2013, 2014 and 2015 in Alentejo (South Portugal). We examined the diurnal and seasonal response of two V. vinifera varieties Aragonez (syn. Tempranillo) and Touriga Nacional subjected to sustained deficit irrigation (SDI), and regulated deficit irrigation (RDI, about 50% of the SDI). Diurnal canopy (TC), and soil surface (Tsoil) temperatures were assessed by thermography. Punctual measurements of leaf temperature with thermal couples, leaf water potential and leaf gas exchange were also done.
TC values were above the optimal temperature for leaf photosynthesis during part of the day light period (11:00-14:00h to 17:00h), especially under stressful atmospheric conditions (high VPD, high Tair) and under regulated deficit irrigation. Tsoil was on average about 10-15°C higher than TC. We found strong correlation between TC (derived from thermography) and major physiological traits (leaf water potential and leaf gas exchange). Our results suggest that Tc can be explored as a simple but robust non-intrusive thermal indicator of grapevine performance and also as a parameter to feed grapevine growth models and to estimate heat and water fluxes in irrigated vineyardsinfo:eu-repo/semantics/publishedVersio
Seasonal dynamics of terrestrial vertebrate abundance between Amazonian flooded and unflooded forests
The flood pulse is the main factor structuring and differentiating the ecological communities of Amazonian unflooded (terra firme) and seasonally-flooded (várzea) forests as they require unique adaptations to survive the prolonged annual floods. Therefore, várzea and terra firme forests hammer out a spatio-temporal mosaic of resource availability, which may result in landscape scale seasonal movements of terrestrial vertebrates between adjacent forest types. Yet the lateral movements of terrestrial vertebrates between hydrologically distinct neighbouring forest types exhibiting staggered resource availability remains poorly understood, despite the important implications of this spatial dynamic for the ecology and conservation of forest wildlife. We examined the hypothesis of terrestrial fauna seasonal movements between two adjacent forest types at two contiguous sustainable-use forest reserves in Western Brazilian Amazonia. We used camera trapping data on the overall species richness, composition, and abundance of nine major vertebrate trophic guilds to infer on terrestrial vertebrate movements as a function of seasonal changes in floodplain water level. Species richness differed in neighboring terra firme forests between the high-and low-water phases of the flood pulse and terra firme forests were more species rich than várzea forests. There were clear differences in species composition between both forest types and seasons. Generalized Linear Models showed that water level was the main factor explaining aggregate abundance of all species and three trophic guilds. Our results indicate that the persistence of viable populations of large terrestrial vertebrates adjacent to major Amazonian rivers requires large, well-connected forest landscapes encompassing different forest types to ensure large-scale lateral movements by forest wildlife
Analysis of pancreas histological images for glucose intolerance identificationusing ImageJ-preliminary results
The observation in microscopy of histological
sections allows us to evaluate structural differences,
in pancreatic cells, between rats with normal
glucose tolerance and with glucose intolerance
(pre-diabetic) situation. Nevertheless, this
pre-diabetic condition implies subtle changes in
islets of Langerhans structure. This and the normal
variability among sampled cells makes difficult
the task of identifying glucose intolerance
(pre-diabetic situation) with a low level of error.
This paper presents preliminary results in the processing
of histological pancreas images with the
goal of identifying pre-diabetic situation in Wistar
rats. The immediate goal of this work is to
evaluate the performance of a classifier based in
a morphometric measurement of the histological
images and to assess the potential for image based
automatic processing and classification. A set of
90 images, were used (58 from rats with normal
glucose tolerance, and 32 from pre-diabetic ones).
These images were segmented manually using ImageJ.
This segmentation and area measurements
have been speedup by the application of ImageJ
macros which were defined for this purpose. The
ratio, between the area of -cells and the islets of
Langerhans , was used has the indicator of the prediabetic
situation. Considering this feature, a receiver
operating characteristic analysis has been
performed. True positive rate, vs. false positive
rate shows the predicted performance of a binary
classifier as its discrimination threshold is varied
A New Age for Quercus spp. Fruits: Review on Nutritional and Phytochemical Composition and Related Biological Activities of Acorns
The current global food system must adapt to the expected growth of world population (about 9 billion individuals by 2050). This adaptation will probably include an increased consumption of edible wild foods, due to their richness in micronutrients and bioactive compounds, besides providing a cost-effective and sustainable way of improving caloric food security. A striking example of such natural matrices is the Quercus genus, which has the additional advantage of being widespread throughout the Northern Hemisphere. In a traditional sense, Quercus fruits (acorns) were mainly used in animal feeding, despite their potentially important role on the rural economy. But this preconception is changing. In fact, their nutritional value, high contents in phytochemical compounds, biological activity (such as antioxidant, anticarcinogenic, and cardioprotective properties) and use in the treatment of specific diseases (such as atherosclerosis, diabetes, or Alzheimer's disease) have raised the interest in integrating acorns into the human diet. Accordingly, this comprehensive overview was designed to provide an evidence-based review of the literature, with the objective to achieve useful conclusions regarding the nutritional properties, methodologies of extraction, identification, and characterization of a wide variety of bioactive compounds and scientifically validated bioactivities in Quercus species worldwide. The industrial by-products from acorn oil extraction or flour production are also included. Data regarding the analytical techniques, individual compounds, and their bioactivities, are organized in tables. The reported data are discussed and directions for further investigations are suggested, highlighting the use of acorns in food, nutraceutical, and pharmaceutical applications.The authors are grateful for the financial support (UID/QUI/
50006/2013-POCI/01/0145/FEDER/007265) from FCT/
MEC through national funds and cofinanced by FEDER, under
the Partnership Agreement PT2020. J.C.M. Barreira thanks FCT,
POPH-QREN, and FSE for his grant (SFRH/BPD/72802/
2010).
The authors thank Telma Oliveira for drawing the acorn sketch
depicted in Figure 1.info:eu-repo/semantics/publishedVersio
Can soil water content be used as a predictor of predawn leaf water potential for deficit irrigation scheduling? A case study at Alentejo wine region
Context and purpose of the study: Water and heat stress impose new challenges to irrigation management
in the Mediterranean areas. This reality has a major impact on the vineyard ecosystem, particularly on the
scarce water resources of the Alentejo region (South Portugal). To mitigate this problem, irrigation
management should focus on optimizing yield and fruit quality per volume of water applied. This work aims
to discuss the use of predawn leaf water potential and soil water status relationships as a decision tool for
irrigation management taking as basis data from a field trial where two deficit irrigation strategies were
comparedinfo:eu-repo/semantics/publishedVersio
Intersubject variability of blood analysis reference values: assessment of age and locality influence by means of a linear discriminant analysis model
Glycemic and lipidic profiles might be influenced by several factors. The fact that the age group might alter the most extensively evaluated lipidic and glycemic parameters is a more or less well accepted fact. To verify this empirical notion, 996 human subjects aged between 21 and 90 years from different localities were characterized according to age. To assess lipid profile, total cholesterol and cholesterol associated with lipoprotein fractions (c-LDL and c-HDL) and triglycerides were determined. Regarding glycemic profile, glucose and glycated hemoglobin were measured. The majority of the population had values of lipidic parameters fit into the reference values, presenting low or moderate risk for developing cardiovascular disease. Blood glucose was often far above the desirable, but this can be devalued due to the HbA1c values, which were overwhelmingly located in the normal range. The categorization of data in different age groups did not allow defining statistically significant differences. Despite the discriminant linear model was presented, the results indicate that age group did not act as a strong discriminant factor. Somehow unexpectedly, the most significant differences were found among the different localities, which tended to show a similarity according with their latitude. Furthermore, there were no significant correlations in the parameters associated with lipidic profile, but there was a direct correlation between glucose levels and HbA1c (glycemic parameters)
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