3,667 research outputs found
Foraging Behaviour and Herbage Intake in the Favourable Tropics/Sub-Tropics
Herbage intake by animals grazing tropical/sub-tropical pastures is directly related to bite mass, as it is for those grazing temperate pastures. Where these swards have low proportions of stem and dead material (controlled swards), herbage intake follows a similar pattern to that of temperate pasture species, but leaf characteristics, such as lamina length play an important role and influence the short-term rate of intake. Sward structural characteristics and behavioural factors are relatively more important than nutritional factors in terms of herbage intake regulation. The feeding value of the herbage produced is potentially adequate to sustain high levels of beef cattle performance under controlled sward conditions, but relatively limited for dairy cows, since nutrient concentration in the forage is not optimal for high levels of daily milk yield. Sward targets for attaining production objectives are now a feasible management practice on tropical pastures and should be evaluated further
Foraging Behaviour and Herbage Intake in the Favourable Tropics/Subtropics
Key points
1. Herbage intake by animals grazing tropical/sub-tropical pastures is directly related to bite mass, as it is for those grazing temperate pastures.
2. Where these swards have low proportions of stem and dead material (controlled swards), herbage intake follows a similar pattern to that of temperate pasture species, but leaf characteristics, such as lamina length play an important role and influence the short-term rate of intake.
3. Sward structural characteristics and behavioural factors are relatively more important than nutritional factors in terms of herbage intake regulation. The feeding value of the herbage produced is potentially adequate to sustain high levels of beef cattle performance under controlled sward conditions, but relatively limited for dairy cows, since nutrient concentration in the forage is not optimal for high levels of daily milk yield.
4. Sward targets for attaining production objectives are now a feasible management practice on tropical pastures and should be evaluated further
Mini Tomato Production In Organic System Under Greenhouse With Partial Control Of Meteorological Elements
The objective of this research was to evaluate the meteorological elements of the environments and the production components of mini tomato crop in organic system in different forms of cultivation, biofertilizer doses and technological levels of protected environments. The research was conducted in completely randomized design in a 3 x 2 x 5 factorial scheme, corresponding to three greenhouses (A - climatized, B - mobile screen and C - fixed screen), two forms of cultivation (pots and beds) and five doses of a commercial biofertilizer (0, 50, 100, 150 and 200% of dose indicated), with five replicates. The treatments affected the analyzed variables, except for biofertilizer doses and interaction of treatments. Air temperature was unchanged among the environments and the mean and minimum relative humidity were within the control range in the climatized greenhouse. The greenhouse with mobile screen showed the best production results for the cultivation in beds and the biofertilizer doses were indifferent for all treatments.20980080
Conformal prediction for frequency-severity modeling
We present a nonparametric model-agnostic framework for building prediction
intervals of insurance claims, with finite sample statistical guarantees,
extending the technique of split conformal prediction to the domain of
two-stage frequency-severity modeling. The effectiveness of the framework is
showcased with simulated and real datasets. When the underlying severity model
is a random forest, we extend the two-stage split conformal prediction
procedure, showing how the out-of-bag mechanism can be leveraged to eliminate
the need for a calibration set and to enable the production of prediction
intervals with adaptive width
Metaheuristic Approaches for Hydropower System Scheduling
This paper deals with the short-term scheduling problem of hydropower systems. The objective is to meet the daily energy demand in an economic and safe way. The individuality of the generating units and the nonlinearity of their efficiency curves are taken into account. The mathematical model is formulated as a dynamic, mixed integer, nonlinear, nonconvex, combinatorial, and multiobjective optimization problem. We propose two solution methods using metaheuristic approaches. They combine Genetic Algorithm with Strength Pareto Evolutionary Algorithm and Ant Colony Optimization. Both approaches are divided into two phases. In the first one, to maximize the plant’s net generation, the problem is solved for each hour of the day (static dispatch). In the second phase, to minimize the units’ switching on-off, the day is considered as a whole (dynamic dispatch). The proposed methodology is applied to two Brazilian hydroelectric plants, in cascade, that belong to the national interconnected system. The nondominated solutions from both approaches are presented. All of them meet demand respecting the physical, electrical, and hydraulic constraints
Investigação sobre níveis de nutrientes no solo visando otimização da fixação biológica de nitrogênio em feijão-caupi.
Generic system for human-computer gesture interaction: applications on sign language recognition and robotic soccer refereeing
Hand gestures are a powerful way for human communication, with lots of potential applications in the area of human computer interaction. Vision-based hand gesture recognition techniques have many proven advantages compared with traditional devices, giving users a simpler and more natural way to communicate with electronic devices. This work proposes a generic system architecture based in computer vision and machine learning, able to be used with any interface for human-computer interaction. The proposed solution is mainly composed of three modules: a pre-processing and hand segmentation module, a static gesture interface module and a dynamic gesture interface module. The experiments showed that the core of visionbased interaction systems could be the same for all applications and thus facilitate the implementation. For hand posture recognition, a SVM (Support Vector Machine) model was trained and used, able to achieve a final accuracy of 99.4%. For dynamic gestures, an HMM (Hidden Markov Model) model was trained for each gesture that the system could recognize with a final average accuracy of 93.7%. The proposed solution as the advantage of being generic enough with the trained models able to work in real-time, allowing its application in a wide range of human-machine applications. To validate the proposed framework two applications were implemented. The first one is a real-time system able to interpret the Portuguese Sign Language. The second one is an online system able to help a robotic soccer game referee judge a game in real time
Interactive Tree and N Supply Effect on Root Mass of Two Annual Pasture Grasses
A major aim of integrated crop livestock system (ICLS) with trees is to increase the overall land productivity and/or its sustainability by making best use of the environmental resources (water, light and nutrients) used by plant for growth (Jose et al. 2008). Consequently, research efforts have been done in order to investigate the complex animal-plant-soils interactions operating upon the biological production of these systems, and their environmental impacts. For instance, since roots return to soil as a stock of C in the soil is in general larger than shoot return, interest in describing plant root system has increased due the current debate over sequestration of C by vegetation. Therefore, an important issue of ICLS is the degree of competition or, conversely, the complementary level that exists between root development and root system activities (Gregory 2006). However, our knowledge about the mechanisms by which biomass allocation (aerial parts of the plant vs. root system) is regulated is poor (Poorter et al. 2011), mainly when considering simultaneous stresses (e.g. light and nutrients). In the present study we report the shoot:root ratio and root mass variation responses to N fertilization levels of two forage grass species growing in field situation under a tree canopy while grazed by beef heifers versus an open, treeless ICLS
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