Author: Sukhada Mohandas
Publisher: Springer
ISBN: 9811015856
Category : Science
Languages : en
Pages : 345

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Book Description
Bananas and plantains are among the most important food and cash crops in the world. They are cultivated in more than 135 countries, across the tropics and subtropics, with an annual global production of ca. 130 million metric tonnes. Though bananas are one of the most important components of food security in many developing countries, banana production is threatened by both abiotic and biotic stresses. These include a wide range of diseases and pests, such as bunchy top virus, burrowing nematodes, black Sigatoka or black leaf streak, Fusarium wilt, etc. In recent years, considerable progress has been made and several biotechnological and genomic tools have been employed to help understand and unravel the mysterious banana genome. Molecular and genomic studies have helped to decipher the Musa genome and its evolution. Genetic linkage map and whole genome sequencing of both Musa acuminata and Musa balbisiana (progenitors of cultivated banana) have completely changed the way of thinking and the approach on banana crop improvement. Whole-genome sequencing has helped to improve the selection of quantitative traits such as yield, as well as the selection of optimal parents for developing required hybrids in breeding programs. Gene isolation and the analysis of mutants have helped in the characterization of genes of agronomic value and the associated regulatory sequences. With the advent of molecular markers and new statistical tools, it is now possible to measure the diversity, identify genes and useful alleles linked to important agronomic traits. Further these alleles can be incorporated into cultivars through marker assisted selection or through transgenic approach. Transgenic approaches are potential tools for direct transfer of these genes into popular cultivars, which are generally not amenable for conventional breeding techniques, in specific with crops such as bananas which are sterile, triploid and heterozygous thereby making it difficult to reconstruct the recurrent genotypes in banana. Transgenic techniques thus have helped overcome the difficulty of working with sterile, triploid banana crop. In the last five years, enormous amount of new information and techniques have been generated for banana. A comprehensive book entitled “Banana: Genomics and Transgenic Approaches for Genetic improvement” on banana genomics, latest transgenic technologies and tools available for improved crop development in banana will address all these requirements.

Author: A. I?U. Grosberg
Publisher: World Scientific
ISBN: 9812839224
Category : Technology & Engineering
Languages : en
Pages : 347

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Book Description
?? Giant molecules are important in our everyday life. But, as pointed out by the authors, they are also associated with a culture. What Bach did with the harpsichord, Kuhn and Flory did with polymers. We owe a lot of thanks to those who now make this music accessible ??Pierre-Gilles de GennesNobel Prize laureate in Physics(Foreword for the 1st Edition, March 1996)This book describes the basic facts, concepts and ideas of polymer physics in simple, yet scientifically accurate, terms. In both scientific and historic contexts, the book shows how the subject of polymers is fascinating, as it is behind most of the wonders of living cell machinery as well as most of the newly developed materials. No mathematics is used in the book beyond modest high school algebra and a bit of freshman calculus, yet very sophisticated concepts are introduced and explained, ranging from scaling and reptations to protein folding and evolution. The new edition includes an extended section on polymer preparation methods, discusses knots formed by molecular filaments, and presents new and updated materials on such contemporary topics as single molecule experiments with DNA or polymer properties of proteins and their roles in biological evolution.

Author: Khalid Rehman Hakeem
Publisher: Springer Science & Business Media
ISBN: 1461470285
Category : Science
Languages : en
Pages : 504

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Book Description
The improvement of crop species has been a basic pursuit since cultivation began thousands of years ago. To feed an ever increasing world population will require a great increase in food production. Wheat, corn, rice, potato and few others are expected to lead as the most important crops in the world. Enormous efforts are made all over the world to document as well as use these resources. Everybody knows that the introgression of genes in wheat provided the foundation for the “Green Revolution”. Later also demonstrated the great impact that genetic resources have on production. Several factors are contributing to high plant performance under different environmental conditions, therefore an effective and complementary use of all available technological tools and resources is needed to meet the challenge.

Author: Gregorio Varela
Publisher: John Wiley & Son Limited
ISBN: 9780895736482
Category : Technology & Engineering
Languages : en
Pages : 202

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Book Description

Author: Andre Botequilha Leitao
Publisher: Island Press
ISBN: 1597267724
Category : Architecture
Languages : en
Pages : 277

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Book Description
This practical handbook bridges the gap between those scientists who study landscapes and the planners and conservationists who must then decide how best to preserve and build environmentally-sound habitats. Until now, only a small portion of the relevant science has influenced the decision-making arenas where the future of our landscapes is debated and decided. The authors explain specific tools and concepts to measure a landscape's structure, form, and change over time. Metrics studied include patch richness, class area proportion, patch number and density, mean patch size, shape, radius of gyration, contagion, edge contrast, nearest neighbor distance, and proximity. These measures will help planners and conservationists make better land use decisions for the future.

Author:
Publisher:
ISBN:
Category : Biochemistry
Languages : en
Pages : 906

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Book Description

Author: Kenneth J. Frey
Publisher: Wiley-Blackwell
ISBN:
Category : Science
Languages : en
Pages : 516

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Book Description

Author: Sharron Sue Quisenberry
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 454

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Book Description

Author: Rais Akhtar
Publisher:
ISBN:
Category : Environmental health
Languages : en
Pages : 408

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Book Description

Author: Constanza Verónica Carrasco Jara
Publisher:
ISBN:
Category :
Languages : es
Pages : 0

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Book Description
Típicamente, la extracción de semillas oleaginosas con dióxido de carbono (CO2) supercrítico asume condiciones ideales tales como un tamaño y forma de partícula única, temperatura y presión constantes, y un patrón de flujo tipo tapón de CO2 en el lecho empacado. Sin embargo, dichos supuestos no necesariamente se aplican industrialmente, ya que las condiciones operacionales a dicha escala no se encuentran totalmente controladas. Dado lo anterior, es que se requieren descripciones matemáticas confiables para la extracción con fluidos supercríticos, que incorporen dichas condiciones no ideales, con la finalidad de facilitar el diseño del proceso industrial, y determinación de su viabilidad técnica y económica. El objetivo de este trabajo fue desarrollar y aplicar una metodología experimental y posteriormente un modelo robusto de transferencia de masa, que sea capaz de cuantificar el efecto de la distribución del tamaño de partícula en el rendimiento y velocidad de una extracción con CO2 supercrítico. Para los experimentos de laboratorio se usó como sustrato semillas de arándano rojo (Vaccinium oxycoccus) peletizadas en un molino plano tipo D (R) y cortadas en cilindros con relación de altura a diámetro unitaria, correspondientes a su diámetro equivalente (dpe). Para llevar a cabo los experimentos se utilizó el sistema de extracción SFE de Thar Technologies, para muestras de tamaño pequeño (dpe = 2 mm), muestra de tamaño grande (dpe = 4 mm) y para una mezcla 1:1 (p/p) por un tiempo de 3,5 horas, en un extractor de 200 cm3 (diámetro interno = 5 cm) usando 20 g/min de CO2 supercrítico con una velocidad superficial de 0,19 mm/s en condiciones de operación a 40 oC y 30 MPa. En cada extracción se usaron 120 gramos de material vegetal y todos los experimentos fueron realizados por triplicado. Posteriormente, y con la finalidad de modelar las curvas de extracción obtenidas a escala laboratorio, se utilizó el modelo Linear Driving Force (LDF) de manera modificada, considerando la isoterma de partición de aceite para semillas oleaginosas pre-prensadas utilizando la solubilidad del aceite en el CO2 supercrítico (Csat) y la difusividad efectiva del aceite en el sustrato (De) en condiciones del proceso (40 oC y 30 MPa) como los dos parámetros que mejor se ajustan. El modelo matemático se adaptó para un sustrato con una distribución de tamaño de partícula, en el cual las tasas de extracción individuales están determinadas por el modelo LDF para cada fracción de tamaño como función del tiempo de extracción y posición axial en el lecho empacado considerando la concentración única del aceite en el CO2 en ese momento y posición. Luego, dicho modelo se usó para simular la curva de extracción experimental de la mezcla homogénea sin ningún parámetro de ajuste, solo considerando los valores de Csat y De estimados para las muestras de tamaño pequeñas (dpe = 2 mm) y muestras de tamaño grande (dpe = 4 mm). Los resultados, reportan concordancia entre las curvas de extracción simuladas y las obtenidas de manera experimental. Se aprecia de manera notoria, que la curva de extracción de la mezcla se acerca en un comienzo a la curva de tamaño de partícula menor, y hacia el final a la curva de tamaño de partícula mayor. Se aprobaron los resultados simulados y experimentales, validando de esta forma el modelo de sustratos polidispersos. Finalmente, y solo a través de modelación matemática, se utilizó dicho modelo para simular extracciones con CO2 supercrítico en sustratos con diferentes distribuciones de tamaño de partícula, para lo cual se utilizó como características propias de la muestra: la diferencia en la dispersión y la asimetría de las distribuciones normales. De esta simulación se pudo concluir, que los gráficos de extracción de sustratos que poseen la misma tendencia central, considerada para este caso el diámetro medio de Sauter, cambiaba dependiendo de la distribución del tamaño de partícula.