*2.7.1. Examples*

*2.6.3. Demerits*

edge of the surface steps.

*2.6.4. Summary of photolithography*

30 Titanium Dioxide - Material for a Sustainable Environment

sensing and lithium ion batteries.

**2.7. Vapor deposition method**

• The nature of solvents, sensitizers and additives should be well studied.

**Figure 26.** Hierarchical flower-like structures produced by dot patterning [48].

• Sometimes, the step coverage can be poor, i.e., the ability of photoresist to cover the side-

HNSs of Titania are formed via various techniques and different types of structures are formed by these processes. **Table 7** shows the different characteristics of materials obtained by dot patterning. By changing the reaction conditions like time, temperature and pressure and precursor material, different morphological structures are formed, which have different surface area and porosity for applications like dye-sensitized solar cells, photocatalysis, gas

As the name suggests, this method involves deposition of vapors of the required material. The material is vaporized from the source and condenses on the substrate. It may or may not involve chemical reactions. Vapors can be deposited on the substrates by two main processes:

Flipin et al. [76] grew hierarchical TiO2 nanotubes by plasma-enhanced chemical vapor deposition technique. Porphyrins and phthalocyanines were used as cost-effective precursor molecules. First of all, seed layer was grown by polycrystalline anatase films for highly dense and homogenous organic nanowires. Physical vacuum deposition was done to grow organic nanowires (ONWs) of phthalocyanine molecules with sublimation temperature of 250°C. As a result, tunable ONWs in the range between 1 and 30 μm and diameters between 50 and 120 nm were produced. Then, PECVD was done to cap ONWs with TiO2 shells.

Multistacked nanotrees composed of TiO2 nanowires were grown as a result of this synthesis as shown in **Figure 27**. These nanotubes were grown as 1D structures provide maximum electron percolation as compared to 0D nanoparticles due to less grain boundaries. These structures were then employed for DSSCs to evaluate their efficiency for current production.

Yoshitake et al. [77] prepared hierarchical TiO2 structures by CVD method. Titanium tetraisopropoxide (TTIP) was used as a precursor material. About 40 g of water was added to 8 g of TTIP with 2.6 g of dodecyl amine at 273 K. The mixture was stirred with 0.1 M HCl and was kept overnight for aging. The reaction mixture was transferred to autoclave at 373 K for 4 days. The powder obtained was washed with methanol and dry ethyl ether.

**Table 8.** Hierarchical TiO2 nanostructures produced via vapor deposition processes.

*2.7.3. Merits and demerits of PVD*

• Cost of the process is very high.

*2.7.4. Summary of vapor deposition processes*

**3. Conclusions and future prospects**

ing TiO2

work has been done for TiO2

less usage of heat is required for deposition.

• By process like MBE, we can achieve atomic level growth control.

• Vacuum conditions may be required in some depositions.

vapor deposition processes for growth of hierarchical structures.

• Sputtering does not require the use of specific precursor materials as in CVD.

• Processes like sputtering can initiate and undergo PVD, so less use of energy in terms of

Hierarchical Nanostructures of Titanium Dioxide: Synthesis and Applications

http://dx.doi.org/10.5772/intechopen.74525

33

These processes can form well-defined structures. Nanocoatings can also be formed as a result of these processes. Temperature, time and target materials need to be well optimized for distinct structure growth. Pressure in the chamber should be controlled in case of physical

In conclusion, this chapter gives an overview of synthesis of HNSs of Titania via different routes. The chemistry and different parameters affecting the properties of HNSs are also briefly discussed. It can be seen that the employed techniques are very powerful in synthesiz-

heterostructures. In hydrothermal synthesis, by changing parameters of temperature, con-

be changed to 3D HNSs. By providing prolonged time for crystallization, the morphology of particles changes. However, in case of solvothermal synthesis, different solvents provide different structures. By using solvents that provide maximum steric hindrance, the morphology of structures can be controlled. Also, solvents with high boiling points can be used. In microwave synthesis, irradiation time, temperature and solvents are key factors in controlling morphology. This method provides short time for crystallization in the presence of radiations and more nucleation sites are formed. In pulsed laser deposition process, nanotree- and nanoforest-like structures are grown from agglomeration of nanoparticles. Pressure plays an important role in controlling the morphology. By increasing voltage in anodization technique, when the energy provided to target material is increased, the diameter and length of structures formed are increased leading to formation of 3D hierarchical-like structures as end products. In photolithography, the structures engraving are much easier and microfabrication can be done by these structures. Vapor deposition processes are new and very little

thin films of materials and morphologies can be opted by varying parameters like pressure,

temperature, precursors (in case of CVD) and mean free path.

centration of precursors, etching reagents and time, the morphology of TiO2

HNSs in the form of agglomerated nanoparticles, nanospheres, nanoflakes or 1D/3D

HNSs preparation. These processes can be used to grow very

particles can

**Figure 27.** (a and b) SEM images of multistacked nanoforest [76].

**Figure 28.** (a) TEM images of structures formed by CVD and (b) worm-like agglomerated 3D TiO2 structures grown by CVD [77].

CVD of TTIP was done in Pyrex reactor. Pure argon was passed through liquid TTIP at 293 K into the tube where the powder formed by former process was already deposited. After deposition for 24 h, the gas was switched to N2 , which passed through water at 293 K. TTIP was decomposed completely for 12 h and finally the powder was treated in dry air at 393 K for 2 h. Spherical agglomerated structures were produced as a result of this synthesis (**Figure 28**).

#### *2.7.2. Merits and demerits of CVD*


**4. Results**

260 Heat Exchangers – Basics Design Applications

*c c co ci hi ci c c co ci hi ci*

, , , , *c c co ci h c c c co ci h c*

By using the estimated errors of parameters listed in Table 3, the maximum experimental uncertainties in determining q, k, Re, , and were 2.1%, 2.2%, 3.1%, 0.9%, and 3.3%,

Numerical study of the behavior of the microchannel heat exchanger with 3D single-phase fluid flow and heat transfer was done by using the COMSOL Multiphysics software, version 3.5. The algorithm of this software was based on the finite element method. For the COMSOL package, the generalized minimal residual (GMRES) method was used to solve for the model used in this study; the GMRES method was an iterative method for general linear systems. At every step, the method performed minimization of the residual vector in a Krylov subspace [32], and the Arnoldi iteration was used to find this residual vector. To improve the convergence of the iterative solver used by the GMRES method, the Incomplete LU (lower-upper) pre-conditioner was selected for nonsymmetric systems, where LU is a matrix which was the product of a lower triangular matrix and an upper triangular matrix. For the study, water was used as the working fluid. With the mass flow rate of water from 0.1667 to 0.8540 g/s, the Reynolds number was lower than 400 and the working fluid in the microchannels of the heat exchanger was under laminar flow condition [2]. No internal heat generation was specified, resulting in *Qi* = 0. The finite elements in the grid meshes were partitioned to be triangular, as shown in Fig. 5. The maximum element size scaling factor was 1.9, with element growth rate of 1.7, mesh curvature factor of 0.8, and mesh curvature cut-off of 0.05. In Fig. 4, the schematic meshing of the heat exchanger consists of 26,151 mesh

elements, the number of degrees of freedom is 76,411, and a relative tolerance is 10-6.

Fig. 5. Grid mesh diagram of the microchannel heat exchanger.

*Um c m c TT TT m c m c TT TT*

*U m c T T p p m c TT p p*

respectively, for all cases being studied.

**3. Numerical simulation**

1/2 2 2 2 2 2 2

1/2 2 2 2 2 2

, , ,, , , ,,

(15)

(16)


Modulation of the Nanomaterial's Toxicity

Chapter 6

Abstract

Biofunctionalized Polymer

M.V. Ramírez-Marez, M. Herrera-Martínez

Keywords: functionalization, synthesis, polymers, biomaterials

on Shapes and Sizes

and Jorge Alberto Sánchez-Burgos

design of any nanoscale material.

1. Introduction

99

be taken as transport [1, 2].

causing allow stability in the emulsion [3].

Nanomaterials: Implications

F.F. Razura-Carmona, G.A. Prado-Guzmán, A. Perez-Larios,

Nanotechnology has been one of the most widely used tools in various industries such as pharmaceutical, food, and chemistry, among others, for the encapsulation of compounds or even microorganisms. However, an analysis of the methodologies or polymer matrices to be used is rarely generated, and these in turn contribute to the objective of the product that is intended to be designed. In addition to the evaluation of its physicochemical, optical, and rheological characteristics, and others, are a set of technological tools that allow predicting the stability of a colloid, however, some of the factors that have less importance as the effect of the synthesis process on the shape and size that a structure may have, studies have been carried out to evaluate this phenomenon, which has become a determining factor in the

Recently, the science of nanomaterials has gained strength, due to the wide applications as it is in the pharmaceutical, food, agricultural and other industries, since it has been a tool that allows making the objectives of each of them more efficient in comparison with the direct compound applications, because there are different processes to trap them generating this form particles resistant to biochemical oxidations, UV radiation, gastric digestion or even in some cases can

In this context, the advances in technologies for encapsulation has allowed the development and implementation of polymer matrices with enhanced properties, however, in some cases the size and amount of the materials are not adequate

Due to the growing demand for these materials and the large amount of study that exists, the custom synthesis has been generated, which allows us to obtain materials in suitable sizes depending on the characteristics of the objective, through basic techniques and in some cases with the basic elements that are described below.

## Chapter 6


Preface

Multimedia is the common name for media that combine more than one type of individual medium to create a single unit. In everyday language, the term multimedia usually presents an interactive computing project that uses film, text, and sound, such as, for example, interactive encyclopedia, educational compact discs, or DVDs.

Interactive media are the means of communication in which the outputs depend on the inputs made by the user. It is obvious that the user is an active participant in this kind of communication. Media have the same purpose, but the input parameters made by the user add an interaction to this whole story and lead to interesting options when it comes to the output of a given system. Perhaps the most important characteristic of interactivity is the interaction between user and machine, where each of the "participants" intends to have an active role.

Interactive multimedia allows users to combine, control, and manipulate different types of media, such as text, graphics, audio and video materials, and animations. Interactive multimedia obtains the integration of computer, memory, storage, data, supporting devices, and other information technologies. The most common multimedia applications include interactive education and training programs, various games, and electronic encyclopedias. It should be noted that in recent years, multimedia has been increasingly used in education. The possibility of the unification of multiple components (five pillars of multimedia—audio and video, text, graphics, and animation) helps educators to transfer knowledge to students in a unique way. Students learn better and faster using these methods, and teaching material becomes more interesting and the whole process of learning more amusing.

Chapters are listed in a logical order, but they can be arranged differently, depending on the point of view.

The first chapter is an introductory chapter that presents the basic guidelines when it comes to multimedia and interactivity. Special attention is paid to models of interaction and to interactive design. One part of the introductory chapter is dedicated to the patterns of interactions that are defined by conditions and modes of interaction, while the other part is dedicated to the interactivity design and simplified view of the four major phases that define this discipline.

Other chapters can be classified in two sections: Interactive Multimedia and Education (Chapters 2, 3, 4, 5, and 6) and Interactive Multimedia and Medicine (Chapters 7, 8, 9, 10, and 11).

The second chapter deals with the importance of cloud storage in the area of pedagogy, where the collaborative task expresses the interaction between learners of individual differences who learn within collaborative purposes and skills to fulfill a specific purpose. The authors have shown how cloud storage allows information owners to host their information in the cloud and how data access control is an efficient way to ensure information security in the cloud.

**II**

**Section 3**

Positions and Pathways Forward

and Technological Singularity

*Anthony Diniz and Heliana Soares*

*by Consolato M. Sergi*

Experience

*and Nicholas A. Giudice*

*by Charles Potter*

Interactive Multimedia and Medicine **107**

**Chapter 7 109**

**Chapter 8 127**

**Chapter 9 153**

**Chapter 10 183**

**Chapter 11 193**

The Graphical Access Challenge for People with Visual Impairments:

Training Reading, Writing and Spelling Fluency: Centre-Periphery

Digital Pathology: The Time Is Now to Bridge the Gap between Medicine

Calmness in Virtual Environments Enhance User's Spatial Presence

BloodHero: The Power of Gamification in Social Habit

*by Daniela Domingos, Luis Felipe Lima,Thiago Messias, José Feijó,*

*by Nadia Diyana Mohd Muhaiyuddin and Dayang Rohaya Awang Rambli*

*by Jenna L. Gorlewicz, Jennifer L. Tennison, Hari P. Palani*

Dissemination through Interactive Multimedia

The third chapter introduces two concepts that are currently present in the development of play tools for children: *interactive design*, represented by toys that can integrate interactive sensors and actuators to promote new play possibilities, and *design for interaction*, a new tendency focused on how children interact with each other, and how new designs can contribute to these interactions. The authors have obtained a series of studies of children's social interactions when under the influence of different game conditions.

The fourth chapter intends to present the use of gaming on touchscreen multimedia devices for the learning of digitals skills by the elderly. The usage of digital devices like cellphones can be difficult for older adults due to a lack of digital skills required in the use of multimedia devices. The case study was carried out with a group of older adults in four different European countries with multimedia tablets before they attended the training process for learning how to use cellphones.

The fifth chapter provides a critical look at the literature surrounding distance learning education and targets transactional distance theory. It examines in detail three components: structure, interaction (or dialog), and autonomy.

The sixth chapter discusses both the diverse challenges involved in creating an opera and the co-creation environment. The idea of the project was to design a short one-act interactive opera that could be managed within a modest budget. The authors have recycled the 3D virtual designs as the substratum for an online cocreation environment that could be used to elicit public participation in the future development of their operas.

Graphical access is one of the most pressing challenges for individuals who are blind or visually impaired. The seventh chapter discusses some of the factors underlying the graphics access challenge, reviews prior approaches to addressing this longstanding information access barrier, and describes some promising new solutions.

The eight chapter focuses on a reading, writing, and spelling program based on Luria's theories of automaticity, which uses repetitive paired reading and phonological referencing to develop fluency in reading, writing, and spelling. All materials used in program implementation are electronic and are currently delivered using email and cellphone technologies. The first half of the chapter describes the theoretical basis of the program, while the second half focuses on the modular training course and its aims.

The ninth chapter emphasizes the importance of using quantum computing protocols on encrypted data, which is crucial for the permanent implementation of virtual pathology in hospitals and universities. The encryption of digital images may be a requirement for the accreditation of laboratory services—quantum computing results in quantum-mechanical phenomena, such as superposition and entanglement. Digitalization of imaging in radiology is a reality in several healthcare institutions worldwide.

The tenth chapter deals with image-based virtual reality, which is a type of virtual reality but with limited interaction function. Despite this limitation, a realistic virtual environment in image-based virtual reality is expected to enhance users' spatial presence experience, which is supported by a spatial presence theoretical model. The most important part in this theoretical model are primary egocentric reference frames adapting calmness to produce a spatial presence experience.

**V**

The eleventh chapter is dedicated to the development of a mobile application called BloodHero. The lack of blood in hemocenters is an intermittent health problem in Brazil, since there are many difficulties in attracting blood donors. The number of regular donors in Brazil in recent years barely reaches 3% of the population. The proposed application works as a social network, with a game methodology known

I would like to express my sincere gratitude to all the authors and coauthors for their contributions. The successful completion of the book *Interactive Multimedia - Multimedia Production and Digital Storytelling* has been the result of the cooperation of many people. I would especially like to thank the Author Service Manager Ms.

> **Dragan Cvetković** Singidunum University,

Faculty of Informatics and Computing,

Belgrade, Republic of Serbia

as gamification, with the theme of blood donation.

Sandra Maljavac for her support during the publishing process.

The eleventh chapter is dedicated to the development of a mobile application called BloodHero. The lack of blood in hemocenters is an intermittent health problem in Brazil, since there are many difficulties in attracting blood donors. The number of regular donors in Brazil in recent years barely reaches 3% of the population. The proposed application works as a social network, with a game methodology known as gamification, with the theme of blood donation.

I would like to express my sincere gratitude to all the authors and coauthors for their contributions. The successful completion of the book *Interactive Multimedia - Multimedia Production and Digital Storytelling* has been the result of the cooperation of many people. I would especially like to thank the Author Service Manager Ms. Sandra Maljavac for her support during the publishing process.

> **Dragan Cvetković** Singidunum University, Faculty of Informatics and Computing, Belgrade, Republic of Serbia

**IV**

The third chapter introduces two concepts that are currently present in the development of play tools for children: *interactive design*, represented by toys that can integrate interactive sensors and actuators to promote new play possibilities, and *design for interaction*, a new tendency focused on how children interact with each other, and how new designs can contribute to these interactions. The authors have obtained a series of studies of children's social interactions when under the influ-

The fourth chapter intends to present the use of gaming on touchscreen multimedia devices for the learning of digitals skills by the elderly. The usage of digital devices like cellphones can be difficult for older adults due to a lack of digital skills required in the use of multimedia devices. The case study was carried out with a group of older adults in four different European countries with multimedia tablets before

they attended the training process for learning how to use cellphones.

three components: structure, interaction (or dialog), and autonomy.

The fifth chapter provides a critical look at the literature surrounding distance learning education and targets transactional distance theory. It examines in detail

The sixth chapter discusses both the diverse challenges involved in creating an opera and the co-creation environment. The idea of the project was to design a short one-act interactive opera that could be managed within a modest budget. The authors have recycled the 3D virtual designs as the substratum for an online cocreation environment that could be used to elicit public participation in the future

Graphical access is one of the most pressing challenges for individuals who are blind or visually impaired. The seventh chapter discusses some of the factors underlying the graphics access challenge, reviews prior approaches to addressing this longstanding information access barrier, and describes some promising new solutions.

The eight chapter focuses on a reading, writing, and spelling program based on Luria's theories of automaticity, which uses repetitive paired reading and phonological referencing to develop fluency in reading, writing, and spelling. All materials used in program implementation are electronic and are currently delivered using email and cellphone technologies. The first half of the chapter describes the theoretical basis of the program, while the second half focuses on the modular training

The ninth chapter emphasizes the importance of using quantum computing protocols on encrypted data, which is crucial for the permanent implementation of virtual pathology in hospitals and universities. The encryption of digital images may be a requirement for the accreditation of laboratory services—quantum computing results in quantum-mechanical phenomena, such as superposition and entanglement. Digitalization of imaging in radiology is a reality in several health-

The tenth chapter deals with image-based virtual reality, which is a type of virtual reality but with limited interaction function. Despite this limitation, a realistic virtual environment in image-based virtual reality is expected to enhance users' spatial presence experience, which is supported by a spatial presence theoretical model. The most important part in this theoretical model are primary egocentric reference

frames adapting calmness to produce a spatial presence experience.

ence of different game conditions.

development of their operas.

course and its aims.

care institutions worldwide.

**1**

Section 1

Introductory

Section 1 Introductory

**3**

**Chapter 1**

and Interaction

*Dragan Cvetković*

each of them has an active role.

**2. Interaction models**

**1. Introduction**

Introductory Chapter: Multimedia

Interactive media are means of communication in which the output values depend on inputs. This means that the user is actively involved in the communication. The media still has the same purpose, but entries or inputs made by user create the interaction and some interesting options when it comes to the output of the system. Interactive media is referred to conceptual design of interaction, new media, interactivity, interaction between people and computers, graphical user interface, digital culture, interactive design, and virtual reality. One of the most important characteristics of interactivity is the interaction between user and machine, where

Interactive multimedia allows the user to control, combine, and manipulate a variety of media types, such as text, computer graphics, audio and video materials, as well as animation. Interactive multimedia integrates computer, storage, data, phone, TV, and other information technologies. The most common interactive multimedia applications include education and training programs, video games, electronic encyclopedias, and travel guides. The user or participant in an interactive multimedia application changes their role—for the viewer becomes an active participant. It is expected that interactive multimedia systems become the next generation of electronic information systems. It should be mentioned that another name for interactive multimedia is hybrid technology, because it is able to combine the possibilities for storage capacities of computers and a digital database with an

Nowadays, the fastest-changing area is dedicated to the development of teaching materials based on usage of computers, particularly interactive multimedia programs that run on personal computers. These new computer and information technologies offer students and teachers access to materials like never before. Through the storage capacity of the computer, multimedia can "deliver" enormous

The interaction itself involves at least two parties—the user and the system. The previously mentioned participants are complex and completely different in the way of communication and perception of task. The interface must be a link between them in order to have successful interaction. This transcription can fail in a great number of cases for several reasons. The usage of interaction models can help better understand what is happening in the interaction and to identify possible problems. Models allow, together with developing environment, to compare the different

advanced tool for viewing and manipulating these materials.

amounts of data to users in more useful and accessible ways [1, 2].

styles of interaction and to discuss issues of interaction as well [3].

## **Chapter 1**


**9. Conclusions**

By the use of LQR theory we formulated a control-tracking problem and showed those cases when their solution gives members of the PImDm-1 family of controllers. This way heuristics are avoided and a systematic approach to explanation for the excellent performance of the PID controllers is given. The well known one block PID controller architecture is optimal for Linear Quadratic Tracking problem of 2nd order systems with no zero or stable zero.

**Part 2**

**Tuning Criteria**


**2. Theory of production and growth**

266 Fossil Fuel and the Environment

While the mainstream theory of economic growth pays little attention to the role of energy or other natural resources in promoting economic growth, the impact of energy prices on economic activity has attracted significant attention during the last two decades. Resource and ecological economists have criticized this theory in terms of the thermodynamics

Energy development or increased availability of energy is a part of enhanced economic development. But even with trends toward greater energy efficiency and other dampening factors, total energy use and energy use per capita continue to grow in the advanced industrialized countries and even more rapid growth can be expected in the developing countries as their incomes advance. Generally, economic activities, structural and technological changes are important factors influencing energy use. So some time there is

While there is a lack of alternative model of the growth process, extensive empirical work has examined the role of energy in the growth process. The principal finding is that energy used per unit of economic output has declined, but this is to a large extent due to a shift in

The role of energy in production is described in the following using neoclassical concept of the production function. This production theory is very general in comparison to the specific models of economic growth including new factors (such as substitution between energy and other inputs, technological change, shifts in the composition of the energy input, and shifts

Furthermore, energy and economic activity both affect the environment. However, understanding these effects has important implications, while technology has been evolved and improved dramatically. The chapter is structured to cover the key points of energy-

The chapter is organized as follows. We begin with a brief review of theory of production and growth that describe the channels through which increased availability of energy might

In the third part conceptual linkage between energy and development and also the role of economic activity in the energy use trend are described. Development of disaggregated energy indicators makes available a powerful set of analytical tools. Those tools reveal the

The next part reviews energy indicators, which are developed to describe the links between energy use and human activity in a disaggregated manner. After reviewing major indicators, we discuss the basic concepts of various indicators and the methodologies used to derive them. Then we review the use of decomposition methods to aid in the analysis of trends in energy use. The key factors in this analysis are (1) substitution between energy and other inputs within an existing technology, (2) technological change, (3) shifts in the composition of the energy input, and (4) shifts in the composition of economic output.

Then energy and economy are related to the environment. Therefore energy indicators can be extended to carbon emissions which play an important role in aiding negotiations over

carbon reduction targets and evaluating progress toward meeting abatement goals.

implications for economic production and the long-term prospects of the economy.

evidence of mutual interactions between economy and energy.

economy- environment nexus, too.

act as a "key" stimulus of economic development.

energy use from direct use of fossil fuels to the use of higher quality fuels.

relationship between energy uses and their underlying driving factors.

in the composition of economic output) affecting production process (stern, 2004).

This part reviews the background theory of production and growth. The role of energy in production should be considered in order to understand the role of energy in economic growth. Mainstream economists usually think of capital, labor, and land as the primary factors of production, while goods such fuels and materials are intermediate inputs (which are created during the production period under consideration and are used up entirely in production).

However, the theory of growth and its limitations of consideration of natural resource has been the subject of strong criticism. So the background theory of production and growth can be reviewed from different points of view.

There are essentially three mainstream categories of neo-classical growth models (Stern and Cleveland, 2004). The first one focuses on technological change as the only means by which growth can be achieved (Aghion and Howitt, 1998; Solow, 1956; Stern and Cleveland, 2004). Economic growth beyond equilibrium level (where further returns to capital are no longer possible) is only achievable by increasing returns to existing capital via improvements in technology.

The second category focuses on the consumption of natural capital in determining sustained economic growth. These models assume a priori that it is technically feasible to substitute between physical and natural capital (Stern and Cleveland, 2004). Achieving sustained growth relies on the correct institutional conditions (including property rights, market structure, means of considering future generations) to ensure that any depleted natural capital is substituted for with the corresponding value of man-made capital (ockwell, 2008).

The last category of growth model considers both natural resources and technological change as the determinants of growth. (Stern and Cleveland, 2004).

In all three models of economic growth, the contribution of energy to economic activity is only considered relative to its cost within production process. In economic terms, the models consider energy to be an 'intermediate good' rather than a 'primary input' into production. This implies that decoupling economic growth from energy use is a possible subject, in the case of the latter two models. In the following the mentioned growth models are described briefly.


*Zoonotic Trematode Infections; Their Biology, Intermediate Hosts and Control DOI: http://dx.doi.org/10.5772/intechopen.102434*

*Snail families involved as intermediate hosts for trematodes (flukes) causing disease in humans or domestic animals. Only certain species within a family are intermediate hosts for a given parasite.* *Zoonotic Trematode Infections; Their Biology, Intermediate Hosts and Control DOI: http://dx.doi.org/10.5772/intechopen.102434*

#### **Figure 2.**

*Life cycle of schistosomes infecting humans (source: Alexander J. da Silva & Melanie Moser, public health image library (PHIL), Centers for Disease Control and Prevention).*

The species are divided into four groups, i.e., the *S. japonicum* group, the *Schistosoma mansoni* group, the *S. indicum* group and the *S. haematobium* group [8]. Some species primarily infect humans while others primarily infect non-human animals, but infections with the former group may be found in non-human vertebrates and infections with the latter group may be found in humans [9, 10].

Species within the group of *S. japonicum* use as intermediate hosts, species of the Pomatiopsidae. *Schistosoma japonicum* is the major species of medical importance in South-East Asia and the species has many definitive hosts [6]. *Schistosoma mekongi* is found in parts of the Mekong River basin region in Cambodia, Laos, and Thailand [11]. The other species of the *S. japonicum* group are mainly parasites of rats [12] although human infection by *Schistosoma malayanum* are found [11].

The group of *Schistosoma mansoni* has 2 species, *S. mansoni* and *Schistosoma rodhaini* both using *Biomphalaria* spp. (**Figure 3**) as an intermediate host. *S. mansoni* is found throughout sub-Saharan Africa, parts of the Arabian Peninsula and it is the only *Schistosoma* spp. found in South America [8]. The two species hybridize in the wild [12]. Species of the group *S. indicum* occur in the western and southern Asian regions and are commonly found in animals, i.e., ungulates, horses, pigs, and possibly dogs [8]. The species use *Indoplanorbis exustus* as intermediate host [8]. The group associated with *S. haematobium* includes nine species that are the most widespread, i.e., Africa, Indian Ocean Islands, Arabian Peninsula, and Mediterranean regions [8].  Natural interactions and introgressive hybridisation between these species are common [8, 13, 14].

Each of the species of schistosomes infecting humans has a characteristic and limited intermediate snail-host spectrum. The intermediate hosts of *S. mansoni*, *S. haematobium*, *S. intercalatum*, and *S. guineensis* belong to the family Planorbidae or Bulinidae (previously a subfamily of the Planorbidae) while those of *S. japonicum*, *S. mekongi*, and *S. malayensis* are caenogastropods that belong to the Pomatiopsidae [15]. Various species of *Biomphalaria* serve as intermediate hosts for *S. mansoni* (**Figure 3**) and certain *Bulinus* spp. (**Figure 4**) are intermediate hosts for *S. haematobium*, *S. guineensis*, and *S. intercalatum*. For *S. japonicum*, species of the genus *Oncomelania* are the intermediate hosts (**Figure 4**). Species-level relationships within *Oncomelania* are not fully resolved but there seems to be four species that currently transmit *S. japonicum*, i.e., subspecies of *O. hupensis* in eastern China, *O. robertsoni* in western China, *O. quadrasi* in the Philippines and *O. lindoensis* on Sulawesi [16]. For *S. mekongi* and *S. malayensis*, the intermediate host is from the subfamily Triculinae, tribe Pachydrobiini, i.e., *Neotricula aperta* and *Robertsiella kaporensis*, respectively [17, 18] (**Figure 4**). More species can

*Zoonotic Trematode Infections; Their Biology, Intermediate Hosts and Control DOI: http://dx.doi.org/10.5772/intechopen.102434*

#### **Figure 4.**

*Representative species of Bulinus, Oncomelania, Robertsiella and Neotricula. The B. africanus group (a): Bulinus abyssinicus (1), B. africanus (2), B. nasutus (3), B. ugandae (4), B. jousseaumei (5), B. obtusus (6), B. obtusispira (7), B. umbilicatus (8), B. globosus (9), B. productus (10).  The B. forskalii group (c): Bulinus bavayi (20), B. beccarii (21), B. canescens (22), B. cernicus (23), B. crystallinus (24), B. forskalii (25), B. scalaris (26), B. senegalensis (28). The B. reticulatus group (d): B. reticulatus (28), B. wrighti (29). Asian species (e): Oncomelania hupensis smooth (30) form and ribbed form (31), O. quadrasi (32), Robertsiella kaporensis (33), Neotricula aperta (34).*

be infected experimentally but they may not transmit the parasite in nature [19]. For example, there have been reports that *S. haematobium* was transmitted by *Ferrissia* in India; at least three endemic foci of human schistosomiasis have been described in India previously and sporadic autochthonous cases and cercarial dermatitis are also common (see references in [20]). Experimental exposure of *Ferrissia tenuis* to miracidia of *S. haematobium* showed that this snail could be infected and shed cercariae [21]. In the north-western extremity of Africa, *Planorbarius metidjensis* is common and although it is an experimental host for *S. mansoni* and *S. haematobium* [22, 23] there is no evidence that it is a natural host [23].

Snails may be widely distributed in an area, but there is a tendency for infected snails with *Schistosoma* spp. to be focally distributed in particular areas where infected people contaminate the water with their wastes. In some cases, human infections may be facilitated by prior contamination of habitats by reservoir hosts especially for *S. japonicum*, but also possibly for *Schistosoma mansoni* and *S. haematobium*. Snail populations undergo great seasonal variations in density and infection rates. Rainfall and/or temperature are the main causative factors. This results in the pattern of transmission commonly being of a focal and seasonal nature. Although prevalence of infection in the intermediate hosts may be low, this can result in a high percentage of human infections, e.g., in Lake Malawi [24].

#### **2.2 Avian schistosome**

Swimmer's itch or cercarial dermatitis is a short-term immune reaction occurring in the skin of humans that have been penetrated by cercariae of schistosomes (Schistosomatidae) that normally develop in birds or in mammalian hosts other than humans. Genera often associated with swimmer's itch in humans are *Trichobilharzia* and *Gigantobilharzia*, but species such as *Schistosomatium douthitti*, a parasite of rodents, may also cause swimmer's itch. In marine habitats, especially along the coasts, swimmer's itch can occur as well. Symptoms, which include itchy, raised papules, commonly occur within hours of infection and do not generally last more than a week. It is common in freshwater, brackish, and marine habitats worldwide and application of molecular diagnostic techniques has begun to unravel the many schistosome species that can be responsible [25]. Various species of Lymnaeidae, Physidae, Planorbidae, Bulinidae (see some species in **Figures 5** and **6**) and other taxa are intermediate hosts [25–28].

In Thailand, *Indoplanorbis exustus* together with *Lymnaea rubiginosa* are referred to as the "itchy snail" by rural people [29]. These snail species are hosts for a number of schistosomes including *Schistosoma spindale*, *S. indicum*, and *S. nasale*. Though these species do not develop to maturity in humans, they may cause cercarial dermatitis.

#### **2.3 Paragonimus**

Paragonimiasis, also known as pulmonary distomiasis, is a parasitic disease of humans and animals in various parts of the world, but principally in the Orient (Far East). Its etiological agents are species of the trematode genus *Paragonimus* which utilize caenogastropods (specifically superfamilies Cerithiodea and Truncatelloidea) as first intermediate hosts (see examples in **Figures 7** and **8**) and decapod crustaceans, primarily freshwater crabs and crayfish, as second intermediate hosts.

*Zoonotic Trematode Infections; Their Biology, Intermediate Hosts and Control DOI: http://dx.doi.org/10.5772/intechopen.102434*

#### **Figure 5.**

*Some species of the Lymnaeidae, Physidae and Bulinidae. Lymnaeidae: Radix natalensis (1), Pseudosuccinea columella (2), Radix auricularia (3), Galba truncatula (4), Austropeplea viridis (6). Bulinidae: Indoplanorbis exustus (6). Physidae: Aplexa waterloti (7), Physa acuta (8).*

The genus *Paragonimus* contains several species that infect a variety of mammals and birds and some of these species affect other vertebrates. Lung fluke infections are distributed in certain parts of the World where food habits include eating raw crabs, and crayfish, which contain the infective metacercarial cysts. Several million people are thought to be infected with paragonomiasis and almost 300 million are at risk of infection [30, 31]. In Africa, *Paragonimus africanus* is important [32], while in Mexico and Central America *Paragonimus mexicanus* causes occasional human infections [30]. Similarly, in the Midwest states of the USA, a number of human infections with *Paragonimus kellicotti* have been reported. The main endemic areas are in the Orient and Southeast Asia. In these areas, the etiological agent in humans is mainly *Paragonimus westermani* [31].

The cercariae penetrate the soft body parts of the crustacean host and then invade the viscera and muscles of this host, where they usually become encysted in specific organs depending on the species of lung fluke and the species of the crustacean host (**Figure 9**). When the mammalian host, human or reservoir host ingests infected crab or crayfish meat or viscera (raw, soaked in rice wine, or salted), the metacercaria excyst in the duodenum and migrates through the intestinal wall in about an hour, reaching the abdominal cavity in 3–6 h. The larvae of various lung flukes enter and remain in the abdominal wall for several days (up to 3 weeks), then migrate through the diaphragm to the pleural cavity, where they penetrate the serosal layers of the lungs. Finally, they arrive near the bronchioles, where they develop to adult worms in pairs, and exist in tissue capsules laid down by the host, about 6–8 weeks after ingestion of the parasitized crustacean host. The lung capsules containing the worms connect with the respiratory passages of the lung, and the eggs of the parasite are moved along with lung exudates [33].

#### **Figure 6.**

*Species of the Planorbidae (a and c) and Burnupiidae (b). Planorbidae: Planorbella (Helisoma) duryi (1), Planorbarius metidjensis (2), Planorbis planorbis (3), Africanogyrus coretus (5), Ceratophallus natalensis (6), Drepanotrema sp. (7), Gyraulus spp. (8), Polypylis hemisphaerula (9), Segmentorbis spp. (10), Ferrissia sp. (11). Burnupidae: Burnupia sp. (4). The scale shown in part c is also used for part b.*


**Author details**

Marta Kowalska1 , Michal Owecki1,2, Michal Prendecki1 , Katarzyna Wize1 , Joanna Nowakowska1 , Wojciech Kozubski3 , Margarita Lianeri1 and Jolanta Dorszewska1 \*

\*Address all correspondence to<EMAIL_ADDRESS>
1 Laboratory of Neurobiology, Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland

2 Chair and Department of History of Medical Sciences, Poznan University of Medical Sciences, Poznan, Poland

3 Chair and Department of Neurology, Poznan University of Medical Sciences, Poznan, Poland


*3.2. Protective Effect of R. conduplicans AE and Isolated Compounds on Oxidative DNA Damage*

The Fenton's reaction produces the hydroxyl radical, which is a ROS that is detrimental to the human body. Hydroxyl radicals react with different nucleobases, thereby inducing the formation of mutated bases that eventually lead to DNA damage [32]. Figure 5 demonstrated that FR damaged DNA significantly (*p* < 0.001) compared to the control (DMSO + DNA). Though all compounds showed significant protection against hydroxyl radical-induced DNA damage (*p* < 0.001, cpd **10**: *p* < 0.05), compound **14** could not prevent the oxidative damage to DNA (Figures 5 and S49). The genoprotective activity of these compounds and the AE may be attributed to the presence of free radical scavenging potential.


**3.2 Improved rice germplasms and genetic stocks**

Germplasms with improved resistance to both blast and sheath blight diseases are helpful for rice breeders to develop new rice cultivars [34]. Four rice germplasms, LJRIL103 (PI 660982), LJRIL158 (PI 660983), LJRIL186 (PI 660984), and LJRIL220 (PI 660985), with resistance to both blast and sheath blight diseases were

### **Figure 3.**

*Photograph showing a view of the rice research plots of USDA ARS DBNRRC and the University of Arkansas Rice Research Center, Stuttgart, Arkansas, USA, 2016. Most rice resources and mapping populations were advanced in similar field plots. The picture was taken with a drone in 2016.*

### **Table 1.**

*List of major genetic resources for blast and sheath blight resistance in the USA. Most of the rice germplasms are available at USDA-GSOR (www.ars.usda.gov/GSOR).*

identified. They were identified from 800 progenies of a cross between US-adapted rice germplasm Lemont with Jasmine 85 [26]. These germplasms contain suitable agronomic traits in addition to the aromatic nature of LJRIL103, LJRIL158, and LJRIL186. Disease resistance and aromatic genes were tagged with DNA makers to ensure their incorporations.

Loss-of-function mutants can help identify the functionality of the corresponding wild-type allele [35]. For example, lesion mimic mutants (LMMs) with a phenotype resembling hypersensitive cell death without pathogen attack are useful for studying the molecular basis of plant innate immunity. A rice LMM was identified from the rice cultivar Katy after treatment with fast neutrons [36]. The severe lesion mimic phenotype of LMM1 can be induced by blast pathogens and water-related stress, respectively (M.S. Jia and Y. Jia, unpublished data). LMM1 has an enhanced resistance to both blast and sheath blight disease [36]. Genetic analysis suggests that a single recessive gene is responsible for the lesion mimic phenotype in LMM1. Further characterization of the underlying gene in LMM1 will help elucidate the mechanisms of plant innate immunity and abiotic stress responses.

The abovementioned mapping populations, characterized rice germplasms and genetic stocks, are now being used to map and clone *R* genes to both rice blast and sheath blight disease and develop DNA markers for marker-assisted breeding [37].

## **4. User-friendly disease evaluation methods**

In the Southern US, genetic resistance to *M. oryzae* was investigated by Drs. Atkins, Johnston, and Marchetti [20, 38, 39]. Analyses of disease reactions to

**41**

**Figure 5.**

*severity of disease reactions.*

**Figure 4.**

*under field conditions.*

*A Toolbox for Managing Blast and Sheath Blight Diseases of Rice in the United States of America*

*Photographic presentation of the massive production of the sheath blight inoculant for field evaluation. Step 1: mixing A (corn chips) and B (rye) in a 2:1 weight ratio, adding water, and autoclaving twice. Step 2: growing mycelia in petri dishes containing PDA media until the appearance of white sclerotia (C). Step 3: mixing mycelia from C with a mixture of A and B from step 1, and incubating in a sterilized plastic or metal container for 3–5 days until the appearance of white sclerotia (D and E). Step 4: air drying mycelia and sclerotia in brown bags at 24°C with a fan (F). Step 5: grinding mycelia with a grinder (G) before inoculating plants*

*Photographic presentation of two controlled sheath blight evaluation methods. (1) Detached leaf method: mycelia grown on PDA media (A), and PDA plugs removed from a were placed onto detached leaves (6–12 cm in length) (B) at 24°C for 3 days. Symptoms of detached leaves from rice varieties jasmine 85 and M202 after inoculations with three* R solani *isolates versus the control PDA without pathogens (C and D). (2) Soft-drink bottle method: PDA plugs from A were placed onto the bottom of sheaths (E) and covered with 2-L soft-drink bottles (F) for 3–5 days until stable symptoms appeared. Length of lesions was measured for both methods as the*

*DOI: http://dx.doi.org/10.5772/intechopen.86901*

*A Toolbox for Managing Blast and Sheath Blight Diseases of Rice in the United States of America DOI: http://dx.doi.org/10.5772/intechopen.86901*

### **Figure 4.**

*Protecting Rice Grains in the Post-Genomic Era*

C/M doubled haploid GSOR

USDA core collection GSOR

*available at USDA-GSOR (www.ars.usda.gov/GSOR).*

**Plant identification**

200001–200325

GSOR 100361–100600

GSOR100001– 100355

GSOR 101601–102,174

GSOR 102501–102544

GSOR 303101–303287

GSOR 303301–303536

310001–311795

**Key information**

Sheath blight resistance

> Molecular map/blast resistance

Blast and sheath blight resistance

Blast and sheath blight resistance

**Number Year of**

Blast resistance 240 2007 [24]

Blast resistance 42 2012 [27]

Blast 187 2015 [28]

Blast resistance 1795 2015 [29–33]

**release**

325 2006 [23]

355 2007 [25]

574 2009 [26]

236 2015 [28]

**Reference**

**Name of genetic sources**

Early/Katy mapping population

K/Z mapping population

SB5 mapping population

Katy//M202 backcrossing lines

Weedy red rice mapping population 1

Weedy red rice mapping population 2

**Table 1.**

ensure their incorporations.

identified. They were identified from 800 progenies of a cross between US-adapted rice germplasm Lemont with Jasmine 85 [26]. These germplasms contain suitable agronomic traits in addition to the aromatic nature of LJRIL103, LJRIL158, and LJRIL186. Disease resistance and aromatic genes were tagged with DNA makers to

*List of major genetic resources for blast and sheath blight resistance in the USA. Most of the rice germplasms are*

Loss-of-function mutants can help identify the functionality of the corresponding wild-type allele [35]. For example, lesion mimic mutants (LMMs) with a phenotype resembling hypersensitive cell death without pathogen attack are useful for studying the molecular basis of plant innate immunity. A rice LMM was identified from the rice cultivar Katy after treatment with fast neutrons [36]. The severe lesion mimic phenotype of LMM1 can be induced by blast pathogens and water-related stress, respectively (M.S. Jia and Y. Jia, unpublished data). LMM1 has an enhanced resistance to both blast and sheath blight disease [36]. Genetic analysis suggests that a single recessive gene is responsible for the lesion mimic phenotype in LMM1. Further characterization of the underlying gene in LMM1 will help elucidate the mechanisms of plant innate immunity and abiotic stress

The abovementioned mapping populations, characterized rice germplasms and genetic stocks, are now being used to map and clone *R* genes to both rice blast and sheath blight disease and develop DNA markers for marker-assisted

In the Southern US, genetic resistance to *M. oryzae* was investigated by Drs. Atkins, Johnston, and Marchetti [20, 38, 39]. Analyses of disease reactions to

**40**

responses.

breeding [37].

**4. User-friendly disease evaluation methods**

*Photographic presentation of the massive production of the sheath blight inoculant for field evaluation. Step 1: mixing A (corn chips) and B (rye) in a 2:1 weight ratio, adding water, and autoclaving twice. Step 2: growing mycelia in petri dishes containing PDA media until the appearance of white sclerotia (C). Step 3: mixing mycelia from C with a mixture of A and B from step 1, and incubating in a sterilized plastic or metal container for 3–5 days until the appearance of white sclerotia (D and E). Step 4: air drying mycelia and sclerotia in brown bags at 24°C with a fan (F). Step 5: grinding mycelia with a grinder (G) before inoculating plants under field conditions.*

#### **Figure 5.**

*Photographic presentation of two controlled sheath blight evaluation methods. (1) Detached leaf method: mycelia grown on PDA media (A), and PDA plugs removed from a were placed onto detached leaves (6–12 cm in length) (B) at 24°C for 3 days. Symptoms of detached leaves from rice varieties jasmine 85 and M202 after inoculations with three* R solani *isolates versus the control PDA without pathogens (C and D). (2) Soft-drink bottle method: PDA plugs from A were placed onto the bottom of sheaths (E) and covered with 2-L soft-drink bottles (F) for 3–5 days until stable symptoms appeared. Length of lesions was measured for both methods as the severity of disease reactions.*

### **Figure 6.**

*Parafilm method for sheath blight disease evaluation: a PDA containing mycelia (A) in a petri dish containing mycelia after 3 days of culturing at 30°C was removed and covered with parafilm and wrapped onto the second youngest leaf for 3–5 days (B) until stable symptoms appeared. A rating scale based on visual length and area of symptoms was assigned as indicated, with 0 representing immunity and 9 representing extreme susceptibility (C).*

*M. oryzae* have been performed under field conditions where complex biotic and abiotic factors impacting the inheritance of resistance were encountered resulting in inconsistencies of disease reactions. In 1999, Dr. Marchetti and his

**43**

*A Toolbox for Managing Blast and Sheath Blight Diseases of Rice in the United States of America*

colleagues demonstrated that disease reactions under an upland blast nursery were reliable to identify *R* genes among breeding lines [40]. Under greenhouse conditions, the phenotypes of rice to *M. oryzae* are categorized as 0–5 where 0 represents complete immunity, 1 represents hypersensitive cell death showing tiny brown spots, 2 represents infected lesions without mycelia, and, for susceptible reactions, 3–5 exhibit different sizes of lesions with visible mycelia coincident with different levels of resistance [32]. Phenotypes evaluated under the upland rice blast nursery were verified with 200 individuals of a mapping population under greenhouse conditions at DBNRRC [41]. Since then, the greenhouse methods have been used to determine the inheritance and genetic mechanisms of blast resistance [32, 41, 42]. In 2015, several IRRI monogenic lines generously donated by IRRI were added to further identify blast *R* genes

The early evaluation of sheath blight relied on replicated field plot experiments

Disease reactions were scored by visually rating the disease severity on the sheaths

A total of 14 known major blast *R* genes have been used in the USA since 1960s. **Table 2** lists their chromosomal locations, representing germplasms, DNA markers to monitor respective *R* genes, and the avirulent and virulent races of these selected rice germplasms (**Table 2**). Based on field observations, most blast *R* genes are dominant whereas a single haplotype of *R* gene is effective for resistance. Among them, six dominant blast *R* genes *Pia*, *Piks*, *Pi66(t)*, *Pikh*, *Pikm*, and *Pi43(t)/Pi1*, and one recessive *R* gene *pid* were on chromosome 11. Comprehensively, one was found on chromosome 2, two on chromosome 6, one on chromosome 8, one on chromosome 9, and two dominants on chromosome 12. Three of the dominant *R* genes, *Pi9*, *Pi42(t)*, and *Pi43(t)*, provide resistance to all races, while *Pita2/Ptr* is

The genetic markers linked or derived from the cloned *R* genes were developed to predict resistance function and to monitor the existence of each of the *R* genes [31–33, 44–52]. Differential blast races were identified (**Table 2**) and have been

Distinct phenotyping variation of rice after infection via *M. oryzae* in different rice germplasms and in the same germplasm at different growth stages under greenhouse [53] and field conditions are also referred as dilatory, partial, field, and adult resistance interchangeably [54]. A total of 11 blast *R* quantitative trait loci (QTLs) responsible for a phenotypic variation ranging from 5.17 to 26.53% were identified with different blast races under greenhouse conditions [55] (**Table 3**) and verified with different blast isolates/races [56]. Using the same method, four additional blast *R* QTLs were identified from different rice germplasms [57].

and leaves of whole plants. The results of the evaluations are useful for mapping *R* genes. As an alternative, greenhouse methods such as detached leaf, soft-drink bottles, and parafilm methods were developed to validate and verify the function of *R* genes (**Figures 5** and **6**). These greenhouse methods are being used routinely for initial *R* gene discovery because they use less time, labor, land, and fertilizer.

*DOI: http://dx.doi.org/10.5772/intechopen.86901*

under greenhouse conditions [43].

**5. Effective** *R* **genes**

**5.1 Effective major** *R* **genes**

effective to all races except IE1k.

**5.2 Effective minor** *R* **genes**

used to validate their predicted resistance efficacies.

with fungal mycelia grown in corn chips or rye (**Figure 4**).

*A Toolbox for Managing Blast and Sheath Blight Diseases of Rice in the United States of America DOI: http://dx.doi.org/10.5772/intechopen.86901*

colleagues demonstrated that disease reactions under an upland blast nursery were reliable to identify *R* genes among breeding lines [40]. Under greenhouse conditions, the phenotypes of rice to *M. oryzae* are categorized as 0–5 where 0 represents complete immunity, 1 represents hypersensitive cell death showing tiny brown spots, 2 represents infected lesions without mycelia, and, for susceptible reactions, 3–5 exhibit different sizes of lesions with visible mycelia coincident with different levels of resistance [32]. Phenotypes evaluated under the upland rice blast nursery were verified with 200 individuals of a mapping population under greenhouse conditions at DBNRRC [41]. Since then, the greenhouse methods have been used to determine the inheritance and genetic mechanisms of blast resistance [32, 41, 42]. In 2015, several IRRI monogenic lines generously donated by IRRI were added to further identify blast *R* genes under greenhouse conditions [43].

The early evaluation of sheath blight relied on replicated field plot experiments with fungal mycelia grown in corn chips or rye (**Figure 4**).

Disease reactions were scored by visually rating the disease severity on the sheaths and leaves of whole plants. The results of the evaluations are useful for mapping *R* genes. As an alternative, greenhouse methods such as detached leaf, soft-drink bottles, and parafilm methods were developed to validate and verify the function of *R* genes (**Figures 5** and **6**). These greenhouse methods are being used routinely for initial *R* gene discovery because they use less time, labor, land, and fertilizer.