Gainesville, FL, United States
Gainesville, FL, United States
Time filter
Source Type

Joseph R.G.,UFL | Ravunnikutty G.,UFL | Ranka S.,UFL | D'Azevedo E.,Oak Ridge National Laboratory | Klasky S.,Oak Ridge National Laboratory
Proceedings - 25th IEEE International Parallel and Distributed Processing Symposium, IPDPS 2011 | Year: 2011

Particle in cell (PIC) algorithm is a widely used method in plasma physics to study the trajectories of charged particles under electromagnetic fields. The PIC algorithm is computationally intensive and its time requirements are proportional to the number of charged particles involved in the simulation. The focus of the paper is to parallelize the PIC algorithm on Graphics Processing Unit (GPU). We present several performance trade-offs related to small shared memory and atomic operations on the GPU to achieve high performance. © 2011 IEEE.

Mann K.K.,Citrus Research and Education Center | Schumann A.W.,Citrus Research and Education Center | Obreza T.A.,UFL
Precision Agriculture | Year: 2011

The productivity of a citrus grove with variation in tree growth was mapped to delineate zones of productivity based on several indicator properties. These properties were fruit yield, ultrasonically measured tree canopy volume, normalized difference vegetation index (NDVI), elevation and apparent electrical conductivity (EC a). The spatial patterns of soil series, soil color and EC a, and their correspondence with the variation in yield emphasized the importance of variation in the soil in differentiating the productivity of the grove. Citrus fruit yield was positively correlated with canopy volume, NDVI and EC a, and yield was negatively correlated with elevation. Although all the properties were strongly correlated with yield and were able to explain the productivity of the grove, citrus tree canopy volume was most strongly correlated (r= 0.85) with yield, explaining 73% of its variation. Tree canopy volume was used to classify the citrus grove into five productivity zones termed as 'very poor', 'poor', 'medium', 'good' and 'very good' zones. The study showed that productivity of citrus groves can be mapped using various attributes that directly or indirectly affect citrus production. The productivity zones identified could be used successfully to plan soil sampling and characterize soil variation in new fields. © 2010 Springer Science+Business Media, LLC.

Porto L.L.A.A.,University of Brasilia | Salum W.B.,UFL | Alves C.,UPIS
Revista Brasileira de Gestao e Desenvolvimento Regional | Year: 2013

The main objective of this study was to characterize the Sheep and Goat Farming in the region of cutting Jussara in the state of Bahia, in its structure which identifies the main barriers and bottlenecks to the development of activity in the region. The methodology adopted was case study, both qualitative and quantitative sampling and intentional, considering the concentration of cooperators and suppliers of local Cooperative - Cooperative of Rural Entrepreneurs Jussara (COPERJ). To obtain the primary data were applied at random, semi-structured questionnaires for two segments of the chain under study: COPERJ and producers. It was found that the productive chain of the Sheep and Goat Farming in the region is well structured compared to other regions of the Northeast, where producers are organized around and Cooperative Associations, and the flow of production occurs through COPERJ, slaughterhouse regional, independent buyers (middlemen), regional markets and butcher shops, but with higher opportunism among the chain actors. The socioeconomic profile of producers, it was observed that the majority is made up of small landowners dominated the use of family labor and extensive system of animal husbandry, with greater participation of sheep. The administration of the properties is still unprofessional, with little technical assistance and rural extensionfor production and management, and participation of producers in programs such as Bolsa Familia and Pronaf contributes to income generation and improvement of properties. Still, the producers have demonstrated safety and confidence in COPERJ and future of the Sheep and Goat Farming in the region.

Mann K.K.,Citrus Research and Education Center | Schumann A.W.,Citrus Research and Education Center | Obreza T.A.,UFL | Harris W.G.,UFL
Soil Science | Year: 2011

Site-specific crop management based on major yield-limiting soil properties requires an understanding of relationships between citrus production and soil characteristics. To explore these relationships, a 10-ha citrus grove was divided into five productivity zones based on tree canopy volume. These productivity zones were termed as "very poor," "poor," "medium," "good," and "very good." Soil samples were collected from each productivity zone at 15-cm intervals to the lowest diagnostic horizon. Magnitudes of organic matter, cation exchange capacity, extractable nutrients, silt-plus-clay content, and soil-water retention were less for the very low productivity zone than the other four zones. The clay fractions of four higher productivity zones were dominated by hydroxy-interlayered vermiculite and kaolinite, whereas only quartz was detected to 180-cm depth in the very poor zone. The very low silt-plus-clay content and absence of clay-sized phyllosilicates in the rooting zone help to explain the very low moisture and nutrient retention of the very poor productivity soil. The white color (10YR8/1) of the very poor productivity soil E horizon (15-180 cm) serves as readily observable indicator for problems it poses for citrus growth. The predictive models developed using partial least squares explained 45% to 58% and 54% to 71% variance for yield and canopy volume, respectively. The yield in the poor areas of the grove was overpredicted (47%) when the soil properties of the top 15-cm layer were used; however, yield was better predicted with the soil properties up to 60-cm depth. Therefore, the depth used for fertilizer and irrigation recommendations should be up to 0 to 45 or 0 to 60 cm. These predictive models can be used for site-specific crop management of the citrus groves showing variable tree growth. Copyright © 2011 by Lippincott Williams & Wilkins.

Mann K.K.,Citrus Research and Education Center | Schumann A.W.,Citrus Research and Education Center | Obreza T.A.,UFL | Sartain J.B.,UFL | And 2 more authors.
Journal of Plant Nutrition and Soil Science | Year: 2011

Variability in soil properties is a complication for fertilization, irrigation, and amendment application. However, only limited progress has been made in managing soil variability for uniform productivity and increased water-use efficiency. This study was designed to ameliorate the poor-productivity areas of the variable sandy soils in Florida citrus groves by using frequent small irrigations and applying organic and inorganic soil amendments. Two greenhouse experiments were set up with sorghum and radish as bioassay crops in a randomized complete block design (RCBD). The factors studied were two soil-productivity classes (very poor and very good), two water contents (50% and 100% of field capacity), two amendments (phosphatic clay and Fe humate), and two amendment rates (10 and 25 gkg -1 for sorghum and 50 and 100 gkg -1 for radish). Amendments applied at 50 and 100 gkg -1 increased the water-holding capacity (WHC) of poor soil by 2- to 6-fold, respectively. The lower rates (10 and 25 gkg -1) of amendments were not effective in enhancing sorghum growth. The higher rates (50 and 100 gkg -1) doubled the radish growth as compared to the control. The results indicate that rates greater than 50 gkg -1 of both amendments were effective in improving water retention and increasing productivity. Irrigation treatment of 100% of field capacity (FC) increased the sorghum and radish growth by about 2-fold as compared with the 50%-water content treatment. The results suggest that the root-zone water content should be maintained near FC by frequent small irrigations to enhance water availability in excessively drained sandy soils. In addition, application of soil amendments in the root zone can enhance the water retention of these soils. Furthermore, managing variable sandy soils with WHC-based irrigation can increase water uptake and crop production in the poor areas of the grove. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Menezes C.C.,Federal University of Piauí | Borges S.V.,Federal University of Lavras | Carneiro J.D.S.,UFL | Cirillo M.A.,UFL | And 2 more authors.
Boletim Centro de Pesquisa de Processamento de Alimentos | Year: 2012

This study aimed to evaluate the influence of the independent variables concentration of citric acid, concentration of potassium sorbate, and pulp/sugar ratio on consumer acceptance for sweet guava. The results were analyzed using statistical methods such as preference map and response surface methodology to determine the influence of the independent variables. Response surface methodology alone proved insufficient to achieve an optimal formulation for the preparation of sweet guava. Based on preference mapping analysis, consumer preference was observed for treatments using higher concentrations of sugar and citric acid. Parameters of sweetness, appearance and texture influenced consumer preferences.

Fenugreek (Trigonella foenum-graecum L.) is an old world annual, legume forage crop and grows under rainfed conditions of agro-climatic regions with dry climatic areas, long summer and high average annual temperature. It is also a well known spice herb from the Indian subcontinent and a well known medicinal plant due to the presence of a number of important phytochemicals like galactomamnan, disogenin and 4-hydroxyisoleucine. Hence, the plant has been found to be important for the pharmaceutical, nutraceutical and functional food industries. It is a phytochemically-rich chemurgic plant with potential agronomic, pharmaceutical and nutraceutical properties. © 2015, Fundacion CIPAV. All rights reserved.

Basu S.K.,UFL
Livestock Research for Rural Development | Year: 2015

Small grain cereals such as wheat (Triticum aestivum L.) and rice together with maize constitutes three major food and animal feed crops marketed globally. Wheat is cultivated in almost all the major continents and a wide diversity of wheat germplasms and cultivars are known across the globe. Demands for new wheat varieties are consistent. Genetic transformation of cereals such as wheat is challenging and several new methods are currently being explored. © 2015, Fundacion CIPAV. All rights reserved.

Loading UFL collaborators
Loading UFL collaborators