1786 Chapters
Medium 9781780648590

8 Discovery and Characterization of the UV-B Photoreceptor UVR8

Jordan, B.R. CABI PDF

8 

Discovery and Characterization of the UV-B Photoreceptor UVR8

Gareth I. Jenkins*

Institute of Molecular, Cell and Systems Biology, College of Medical,

Veterinary and Life Sciences, University of Glasgow, UK

Introduction

Light is a key regulator of plant growth and development. This phenomenon, termed photomorphogenesis, is vital for the productivity, survival and reproductive capability of plants as it enables them to modulate their development to optimize light capture for photosynthesis, to compete with their neighbours and to control the timing of physiological processes. In addition, light modifies metabolic activity to produce various compounds that provide sunscreen protection and deter pests and pathogens. Pivotal to the whole of photomorphogenesis is the ability of plants to sense different aspects of their light environment, its spectral quality, intensity, incident direction and duration of the photoperiod. For this purpose they have evolved several different photoreceptors, which, in turn, are coupled to signal transduction networks to initiate the relevant physiological responses (Kami et al., 2010).

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Medium 9781780647708

6: The Way Forward

Egli, D.B. CABI PDF

The Way Forward

6

Yield Improvement

The world’s food supply has always depended upon the productivity of grain crops – the land area harvested and the yield per unit area. Converting the production of these grains into food on the tables of the world is a complex and convoluted process, with many social, cultural and economic ramifications, some of which we will discuss later in this chapter. Improvements in agricultural productivity have kept the world reasonably well fed for at least the last half-century or so, as the world population increased from 3 to 7.3 billion (FAOSTAT, 2016). Adequate food supplies are still an important issue in the early years of the 21st century, as we face the challenge of feeding a population that will probably approach 10 billion by 2050, just 34 years from now. This increase in food demand (both quantity and quality) must be met against a background of a changing climate, declining availability of natural resources, including water, and a population that will be increasingly concentrated in urban areas. The productivity of grain crops will have a central role in this drama, as they have had since the beginning of agriculture some 10,000 years ago. There is general agreement that future increases in productivity will come mostly from higher yields, since the opportunities to increase the land area devoted to crop production are limited. The focus of this chapter is on yield improvement and the question of what is the best way forward to einsure a well-fed world in 2050.

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Medium 9781786393647

1 Agriculture, Conflict and the Agrarian Question in the 21st Century

Zurayk, R.; Woertz, E.; Bahn, R. CABI PDF

1 

Agriculture, Conflict and the Agrarian

Question in the 21st Century

Rachel Bahn1,* and Rami Zurayk2

Department of Agriculture and Food Security Program, American University of Beirut, Beirut, Lebanon; 2Department of Landscape Design and Ecosystem

Management, American University of Beirut, Beirut, Lebanon

1

Introduction

Understanding the causes of conflict can help to prevent conflict, inform resolutions to conflict and avoid its most harmful effects. There are

­indications that armed conflict has especially strong effects on agricultural systems (Baumann and Kuemmerle, 2016), while most civil conflicts affect rural areas and their populations (Kalyvas,

2004), whose economies and livelihoods still rely heavily on agriculture. Conflict damages agricultural sectors, disrupts food production systems, destroys assets and household incomes, and contributes to food insecurity and malnutrition (FAO, 2016b). Reports in early 2017 linked famine affecting 20 million individuals to conflict in primarily agricultural settings (Sengupta,

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Medium 9788131807385

Ch_1

Saradindu Panda Laxmi Publications PDF

1

Semiconductor

Fundamentals

1.1

INTRODUCTION

To understand the fundamental concepts of semiconductors, one must apply modern physics to solid materials. More specifically, we are interested in semiconductor crystals.

Crystals are solid materials consisting of atoms, which are placed in a highly ordered structure called a lattice. Such a structure yields a periodic potential throughout the material, which results in some remarkable properties.

Two properties of crystals are of particular interest, since they are needed to calculate the current in a semiconductor. First, we need to know how many fixed and mobile charges are present in the material. Second, we need to understand the transport of the mobile carriers through the semiconductor.

In this chapter, we explain the concepts of energy bands, energy band gaps and the density of states in an energy band. We also show how the current in an almost filled band can more easily be analyzed using the concept of holes.

Two carrier transport mechanisms will be considered. The drift of carriers in an electric field and the diffusion of carriers due to a carrier density gradient will be discussed. Recombination mechanisms and the continuity equations are then combined into the diffusion equation. Finally, we present the drift-diffusion model, which combines all the essential elements discussed in this chapter.

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Medium 9781902375205

(c)  Contractor Issues

Martin Wood Chartridge Books Oxford ePub

Chapter 6

What do you need to do to comply with the Act?

1.     Introduction

2.     Is your agreement covered by the Act?

3.     Payment and Notice Systems

(a)     Payment Systems

(b)     Notice Systems

4.     Adjudication Rules and Procedures

(a)     Construction Act Complaint Adjudication Agreements

(b)     Adjudication - Practical Steps

5.     Specific Concerns for Consultants/Clients/Contractors

(a)     Consultant Issues

(b)     Client Issues

(c)     Contractor Issues

6.     How and when notices are served

7.     How time limits are calculated

8.     Key Points Summary

1.   Introduction

To decide what is needed to comply with the Act, the first question is inevitably whether or not any specific agreement is covered by the Act. This can, in certain circumstances, be a complicated issue and there will often be circumstances where some of the parts of the agreement are covered by the Act and some are not. In those circumstances it is usually prudent to ensure the entire agreement is Construction Act compliant.

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