**Abstract**

Erosion by water is one of the most common types of soil degradation which occurs in all climatic regions and is widely considered to be a serious threat to the long-term viability of agriculture in many parts of the world. Lake Ol Bolossat in Nyandarua County, Kenya, is a high altitude lake that was formed on Rift Valley escarpment and faces the challenge of siltation due to increased soil erosion. Over the last few decades, the lake has been encroached and lake area has been overgrazed reducing the vegetation cover around the Lake. An assessment of spatial soil erosion loss was conducted using USLE model and GIS which showed that most parts of the Lake catchment have soil loss beyond tolerable levels of nine tons per year. The soil erosion range was between zero and 22, 525.5 tons per year. The land uses that were more vulnerable to soil loss are croplands, grazing lands with sparse vegetation and barelands which had soil loss ranges of 10–50 tons, 100 to 1000 tons and 500 to 22,525.5 tons per year respectively. The study recommended for immediate interventions by policy makers, researchers and development partners in curbing the soil loss problem.

**Keywords:** USLE, spatial soil erosion, Nyandarua, soil degradation, modelling, GIS


**3. The usage of genetic programming to predict woven fabric porosity parameters**

Porosity parameters based on an ideal geometrical model of porous structure give woven fabric constructor some useful information about porosity by developing a new product, but they are not in a good agreement with the experimental values. In order to balance the difference between the theoretical and experimental values of porosity parameters, genetic programming was used to develop models for predicting the following macro-porosity parameters of woven fabric: the area of macro-pore cross-section, macro-pore density, open porosity, and equivalent macro-pore diameter. The genetic programming is a variant of evolutionary algorithm methods described in many sources (e.g., [2, 3, 4]). The basic information on the evolutionary algorithms is given at the beginning of the section 4. We implemented Koza's variant of genetic programming [2]. In our research, the independent input variables (the set of terminals) were: yarn fineness *T* (tex), weave value *V*, fabric tightness *t* (%) and denting *D* (ends/dent in the reed). The set of terminals also included random floating-point numbers between –10 and +10. Variegated reed denting was treated as an average value of treads, dented in the individual reed dent. The dependent output variables were: area of macro-pore cross-section *Ap* (10-3 mm2), pore density *Np* (pores/cm2), and equivalent macro-pore diameter (µm). For all modelling, the initially set of functions included the basic mathematical operations of addition, subtraction, multiplication, and division. In the case of modelling the area of macro-pore cross-section and pore density the initially set of functions also included a power function, whereas the set of functions for modelling of equivalent macro-pore diameter included an exponential function. We then used the genetic programming system to evolve appropriate models consist of abovementioned sets of terminals and functions. Open porosity was calculated on the basis of predicted values of the area of macro-pore cross-section and macro-pore density and Equation 17. The equivalent macro-pore diameter was calculated on the basis of predicted values of the area of macro-pore cross-section using Equation 19. The fitness measure for modelling by genetic programming was exactly the same as defined by Equation 33 in section 4. The goal of the modelling was to find such a predictive model in a symbolic form, that Equation 33 would give as low an absolute deviation as possible.

The evolutionary parameters for modelling by genetic programming were: population size 2000, maximum number of generations to be run 400, probability of reproduction 0.1, probability of crossover 0.8, probability of mutation 0.1, minimum depth for initial random organisms 2, maximum depth for initial random organisms 6, maximum depth of mutation fragment 6, and maximum permissible depth of organisms after crossover 17. The generative method for the initial random population was *ramped half-and-half*. The method of selection was tournament selection with a group size of 7. For the purpose of this research 100 independent genetic programming runs were executed. Only the results of the best runs (i.e., the models with the smallest error between the measurements and predictions) are presented in the paper.


Meme/s, 121–123 and iconic images, 122–123 and Lynndie England, 121–123 and postmodern, 121–123 9/11 memorial site, 107–108 Micro-level, 14–17, 24–25, 45, 51, 54, 59–63, 68, 140, 153, 155–156, 163 Military and institution, 9–10, 15, 25, 54–55, 61–62, 109, 163, 167 and heterosexual masculinity, 15, 25, 46, 54–55, 59–61, 63, 170 and the US, 71, 96, 128 Militarisation, 61 militarised femininity, 109, 120, 132 militarised masculinity/ies, 10–11, 46, 55, 112, 163, 167 Militarised maternal body, 131–132 Mohanty, Chandra, 44, 112, 160 and the average-third-world woman, 44 and the feminist postcolonial critique, 89 Motherhood-assault on. (*see also* Aoláin, Fionnuala) and biological, 19 and the removal of war babies, 40–41 the regulation of, 41 Mother as nation, 14, 42 Mullins, Christopher & Roth, Dawn, 12–13, 25–26, 45, 47, 51–52, 160 and state crimes, 13, 15, 47, 160–161

Nazi and the eugenicist policy, 24 and ideology, 24, 29 and Rassenschande, 29–31, 34 Neoliberal agenda, 83, 108 policy, 98, 101, 164

Neoliberalism, 10, 16, 45–46, 53, 69–70, 81–83, 89, 102–103, 105–106, 125, 140, 161, 163 and the international monetary fund, 45, 82 and Jacobson, Ruth, 10, 82–83 and privitisation in Iraq, 67, 82–83, 161 and Syria, 163 and the world bank, 45, 103 Nordberg, Jenny, 3–4, 166 *The underground girls of Kabul.*, 3 Owen, Margaret, 74 on widowhood Iraq, 74 Pakistani army, 21, 36, 161 Patriarchy, 16, 25, 53, 89, 93, 99, 106, 111, 128–129 Perpetrators, 6, 12–13, 17, 20, 26, 37, 40, 45, 49, 54, 58, 63, 83, 87, 106, 108, 115–116, 133, 138–139, 148, 159, 162, 165, 171 Peterson, Spike, 10, 72–74, 80–81, 104 and post conflict informal economies, 67, 73–74, 83, 88, 104, 106 Poitras, Laura, 107 -*astro noise*, 107 President Donald Trump, 92 Rape, 1–3, 16, 19–20, 24–27, 29, 35–41, 91–93, 140, 150–151, 170 as a weapon-of war, 25, 45, 56 Reproductive and body, 14, 22, 29, 35, 41, 68, 93, 161, 164 and the Jewish body, 28, 35 and healthcare, 15, 56, 86–87, 92–98, 171 Richter-Montpetit, Melanie, 71, 115–116, 118 and colonial violence, 118 Safe abortion, 15, 26, 86, 89, 93–98, 169 Said, Edward, 114

and orientalism, 114

Schweickart, Patrocinio, 93 on androcentric reading strategies, 93 Securitisation, 86–87 Semiotics, 121–122, 164 and the sign, signifier and signified, 122 Sexual exploitation and abuse (SEA), 23, 50, 76, 77, 100, 102, 140 and feminist debates, 15, 77–79 and female victims, 3, 31, 37–39, 41, 81, 89, 96, 141, 168 and male victims, 13, 135–136, 139, 141, 143, 159, 162, 170 Sex-selective killing, 11, 138, 140, 148, 150, 153, 155, 156–157 Sexual violence, 85 Sexual violence-related pregnancies, 94–95, 97–98 Sexual slavery, 11, 23, 28, 47, 66–67, 73–80, 83, 96–97, 103, 139, 164 in relation to Iraq, 67, 73 Shannon, Lisa, 43–44, 49–50, 160 *A thousand sisters*, 43 Sjoberg, Laura, 15 the feminist ethics of war, 15, 63 Sjoberg, Laura & Gentry, Caron, 79 and the relative autonomy approach, 79 and militarised femininity, 109, 120, 132 and the whore narrative, 120, 131 Sontag, Susan, 119–120 *On photography*, 119 *Regarding the pain of others*, 119 Spivak, Gayatri, 44–45, 71, 109, 160 and epistemic violence, 44 and the feminist postcolonial critique, 89 Stop Rape Now, 1–3, 85, 137 and GET CROSS, 1–2, 44 Structural violence/violence(s), 13, 15, 19, 69, 75, 83, 85–106, 159–160, 164, 171 Stigma, 38, 73, 143

and the criminalisation of homosexuality, 143 and the fear of reporting, 170 and shame, 58, 143 and honour crimes, 39 Survivor/s, 6, 17, 23, 26–28, 30–36, 39–41, 43–45, 58, 63, 68, 89, 94–95, 97, 137–138, 143–144, 150, 152, 159–160, 168–171 Survival sex, 15, 75–77, 83, 160 in Syria, 103–106 Sylvester, Christine, 93 and art metaphors in international relations, 93 Syria, 96–103 and abortion laws, 96 and unemployment, 88, 101 and denial of education, 15, 86, 98–101, 103 and forcible impregnation, 89, 98, 169 and maternal deaths, 95–97 and neoliberal policies, 98, 101, 103, 164 and patriarchy, 89 and sexual harassment, 105 and the origins of the conflict, 90 and violence against women and girls, 5, 7, 12, 45, 47, 86 and the Yazidi women, 77, 96

Takai, Alexandra, 26–27, 35, 38, 40 and forced impregnation, 21–22, 39–40, 97, 100 the convention on the elimination of all forms of discrimination against women, 11, 93 the Geneva conventions, 11, 57, 94, 97 the international criminal court, 11, 26, 57, 75, 89, 151, 169 the 1971 Liberation War, 10, 13, 19, 21–22, 35–37, 76, 160–161, 164 the Rome statute, 11, 57–58, 60, 76 the united nations declaration on the elimination of violence against women, 11, 69, 93

Trafficking, 47 for sexual purposes, 47 Transactional sex, 75, 78, 79. (*see also* Survival sex) Trump administration, 87, 89, 93, 96–97 unaccompanied and separated children, 142 United nations population fund (UNFPA), 88, 91, 93 and the defunding of, 93–98 United Nations Security Council Resolutions (UNSCR), 85 UNSCR 1325, 57, 137 UNSCR 1483, 67, 82–83 UNSCR 1820, 57, 85, 137 UNSCR 1888, 57, 137 UNSCR 1889, 57, 94 UNSCR 1960, 57 UNSCR 2106, 12, 57, 137, 169 UNSCR 2122, 12, 94 UNSCR 2242, 12 Unsafe abortions, 95–96 Unwanted pregnancies, 89, 92, 96–98 Victims female, 3, 31, 37–39, 41, 81, 89, 96, 141, 168 male, 13, 135–136, 139, 141, 143, 159, 162, 170 Victimisation, 91 Violence(s), 8 against men and boys, 142 against women and girls, 5, 7, 12, 19, 45, 47, 63, 72, 83, 86, 88, 92, 139, 152 definition of, 69 institutional, 161–163 interpersonal, 8, 13, 89, 100, 109, 159, 161, 164 reproductive, 8, 16, 22, 24–25, 28–35, 140, 146, 151–156, 161, 163, 170 structural, 13, 15, 19, 69, 75, 83, 85–106, 159–160, 164, 171

of war/armed conflict, 3–8, 19–20, 22, 56–57, 63, 68, 76–77, 103, 106, 138, 163–169 visual criminology, 1, 12, 16, 108, 110–112, 133, 159 and visuality, 1–3, 44, 86, 93, 111–113 Walklate, Sandra, 13, 114 and mediating suffering, 114 Waller, James, 24–25, 37 and us them, 37 and dehumanisation, 37 war, 9 the distinction between war and armed conflict, 9 war on terror, 13, 16, 68, 70 war-on-terror femininity, 16, 107–133, 167, 171 wartime rape as a by-product, 45, 91 as opportunistic, 25, 160 as recreational rape, 25

as sadistic rape, 28 as a weapon-of-war, 25, 45, 56 war crime tribunals, 58 Geneva conventions and the additional protocols, 57 international criminal tribunal for the former Yugoslavia, 57 international criminal tribunal for Rwanda, 57 western and discourse, 3, 44, 160 Wilcox, Lauren, 136–137 on biopower and biopolitics, 137 woman-as-Jew, 14, 21, 28, 31, 33, 35, 42 woman-as-nation, 7, 13, 19–41, 68, 145, 164 women's media center (WMC), 37, 89, 96 in relation to Bangladesh, 37 in relation to Iraq, 37, 96 women, peace and security (WPS), 4, 85


Preface

This book compiles chapters written by researchers who focus on the development and application of risk assessment approaches in various subjects of hydrology, water quality, human health, and industrial designing.

Risk assessment is a critical component in the evaluation and protection of natural or anthropogenic systems. Conventionally, risk assessment is involved with some essential steps such as the identification of problem, risk evaluation, and assessment review. Other novel approaches are also discussed in the book chapters. This book is compiled to communicate the latest information on risk assessment approaches and their effectiveness. Presented materials cover subjects from environmental quality to human health protection.

It's the editor's expectation that the chapters enclosed in this book will provide helpful information for risk assessment in both academic and industrial fields, and encourage the development and implementation of relevant applications for the protection of environment and human health.

> **Yuzhou Luo, Ph.D.** Department of Land, Air and Water Resources University of California (Davis) USA

**Section 1**

**Risk Assessment in**

**Environmental and Ecosystem Quality**


**2. Frequency domain analysis**

The transient problem is first solved by a formulation in the frequency domain. The time-domain response is then obtained by application a suitable Fourier inversion technique. The response to a steady state, time harmonic excitation is computed for a wide range of frequencies starting at zero Hz. From this frequency response, a transfer function is constructed for every frequency considered. The transfer function is dependent only on the geometric and electromagnetic properties of the grounding system and its environment.

if *i*(*t*) represents the injected current at a point in the grounding system, and *x*(*t*) denotes an observed response, then

$$\mathbf{x}(t) = F^{-1}\mathcal{W}(j\omega) \cdot F[i(t)] \tag{1}$$

where *F* and *F*−1 are the Fourier and inverse Fourier transforms, respectively, *W*(*jω*) is the transfer function, and *ω* is the angular frequency.

The physical model is based on the following assumptions.

2 Computational and Numerical Simulationse

field theory in [26]; Huang & Kasten developed a new hybrid model to calculate the current distribution in both the grounding system and the metallic support conductors, while considering the voltage drop along the grounding system conductors [27]. However, the model was also based on quasi-static electromagnetic field theory, meanwhile, leakage currents and network currents within the grounding system are separately considered in the calculation, their mutual coupling influence is neglected, and the capacitive coupling effect of the earth is also neglected. Otero, Cidras & Alamo developed a hybrid method to calculate the current distribution in a grounding system [28] within which the mutual inductive and capacitive coupling influence among these current flowing and leaking along the conductor is considered. However, only a uniform half infinite earth model is considered. This hybrid method was combined with the FFT, and so the transient response from the grounding system was obtained. These confines in the frequency domain promoted the development of a novel mathematical model in [29]–[32], which introduced the quasi-static complex image method (QSCIM) for calculating the current distribution in a grounding system buried in both horizontal and vertical multilayered earth models in the frequency domain. However, the hybrid method can be further developed to numerically calculate the transient response

Once the multilayered earth model is adopted, the Green's function of a point source will contain an infinite integral for the Bessel function, a complex image method based on Maclaurin's infinite series expansion have been studied in [33] and [34], which has brought up problem about the convergence of the infinite Maclaurin's series. To avoid this convergence problem, QSCIM is introduced to dealt with the infinite integral, which uses finite exponential terms (usually just 3–4 terms) through the Matrix Pencil approach instead

In this paper, based on previous works [28]–[31], combined with the FFT, a novel and accurate mathematical model is developed for calculating the harmonic wave currents of lightning currents distribution along the grounding system buried in multilayered earth model in the frequency domain, within which not only the conducting effect of the harmonic wave currents leaking into the soil, but also capacitive and inductive effects between different layers of soil have been considered. Both leakage currents and network currents within the grounding system and their mutual coupling are considered in the calculation. The earth is modeled by a multilayered earth model. To accelerate the calculation, QSCIM and closed form of Green's function were introduced, and the mutual inductive and conductive

The maximum frequency of applicability of the method is limited by the quasi-static approximation of the electromagnetic fields. For the usual electrodes, it may be applied

The transient problem is first solved by a formulation in the frequency domain. The time-domain response is then obtained by application a suitable Fourier inversion technique. The response to a steady state, time harmonic excitation is computed for a wide range of frequencies starting at zero Hz. From this frequency response, a transfer function is constructed for every frequency considered. The transfer function is dependent only on the geometric and electromagnetic properties of the grounding system and its environment.

from a grounding system buried in multilayered earth model.

of Maclaurin's series to quickly calculate the Green's function.

coefficient have analytical formulae so as to avoid numerical integration.

up to some hundreds of kHz.

**2. Frequency domain analysis**


**Author details**

Marco Bassanello\*, Ugo Coli, Antonio Tegon, Maria Teresa Pasqualini, Aldo Farencena, Matteo Geretto and Maurizio D'Aquino Casa di Cura Giovanni XXIII Monastier di Treviso, Treviso, Italy

\*Address all correspondence to<EMAIL_ADDRESS>
© 2022 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**5.** *Citrus tristeza virus* **defective RNAs**

Another function of the CTV gRNA (-) is to serve as template to produce high quantities of single and double strain sgRNAs during the expression mechanism of the ten ORFs situated at the 3´half of the genome (Figure 4 and 5) [44, 48, 49, 50]. Unlike the large animal viruses of the *Nidovirales*, the 3´ sgRNAs of CTV do not share a common 5´ terminus and the sgRNA transcription mechanism resembles the transcriptional mechanism of other Sindbis-like viruses [50]. The synthesis of each 3´ coterminal sgRNA is controlled by its corresponding cisacting element (controller element (CE)) (Figure 4). Probably each CTV CE could act as promoter or terminator of the CTV RNAs during the replication process [44, 48, 49, 50]. However, if the CEs function as internal promoters for the generation of positive-strand sgRNAs, using as template the CTVgRNA(-) molecules (Figure 4), or act as terminators for the synthesis of negative-strand gRNAs (by premature termination at the CE site), or both, is still unclear [44]. In addition to the plus and minus- sense 3´coterminal sgRNAs, the CEs corre‐ sponding to each of the ten 3´ORFs produce a reduced amount of a set of 5´coterminal positivestrand sgRNAs (Figure 4), probably due to premature termination during the synthesis of the CTV gRNA(+) [44]. Moreover, CTV generates significant amounts of *low molecular-weight tristeza* (LMT1 and LMT2), two positive-strand 5´co-terminal sgRNAs population with heterogeneous 3´termini at nt 842-854 and 744-746, respectively (Figure 4 and 5) [46, 47]. LMT 1 and LMT 2 are generated and accumulated differently [51, 52]. LMT1 is likely created by premature termination during CTV gRNA(+) synthesis at a 5´ CE situated in the PRO I domain of the replicase (Figure 4). This 5´ CE acts as a strong promoter when placed immediately upstream of the ORFs near the 3´ terminus [51]. In contrast of the 3´ CEs, which are able to generate plus and minus-strand sgRNAs, the 5´ CE of the LMT 1 only promoted the synthesis of positive-strand sgRNAs (Figure 4) [51]. In fact, the RNA termination and initiation sites of the 5' CE, compared to those of 3' CEs, occur at opposite ends of the corresponding minimal active CE site [49]. Therefore, as a result of the replication process, CTV produces high amounts of viral RNA species in the infected cell (Figure 4). The total (gRNAs plus sgRNAs) positive to negative-strand RNA ratio (approximately 40 to 50:1) falls within the range of the genomic RNAs of most positive-strand RNA viruses, particularly the more similar alphavirus super‐ group and large complex viruses of the *Nidovirales* [26]. However, during CTV replication, only the positive-strand gRNA accumulates approximately 10 to 20 times more than their negative-strand gRNA homologues, a rather lower ratio compared to those generated during

8 Current Issues in Molecular Virology - Viral Genetics and Biotechnological Applications

The expression of the CTV genome, which potentially yields at least nineteen protein products, resembles that of *Coronaviruses* [50]. This remarkable process includes at least three different RNA expression mechanisms widely used by positive-strand RNA viruses: proteolytic processing of the polyprotein precursor, translational frameshifting and the generation of a nested set of ten 3'-coterminal sgRNAs [50]. Therefore, the ORFs 1a and 1b are directly translated, from the positive-strand gRNA, to yield a 400 kDa polyprotein that is later proteolytically processed in, at least, nine protein products. The ORF1b encodes a 54 kDa protein with RdRp domains that is occasionally translated after ORF 1a by a +1 ribosomal frameshifting [2]. Additionally, as indicated above, the 10 ORFs located at the 3' half of the CTV genome are expressed by the synthesis of ten 3' co-terminal sgRNAs (Figure 4). Each 3' sgRNA serve as RNA messenger for the translation of its 5' proximal ORF [13, 46] and the

other RNA viruses replication [17].

In addition to the 35 different species of RNA created during replication, CTV could accumu‐ late considerable amounts of D-RNAs in infected cells (Figure 5) [46]. CTV D-RNAs vary in size, abundance and sequence [41, 45, 46] and could be encapsidated into particles and could be transmitted by aphids [45].

Generally, D-RNAs bear a genome from 2.0 to 5.0 kb and are composed by variable portions of the 3' and 5' termini of CTV genomic RNA with large internal deletions (Figure 5). Never‐ theless, some D-RNAs comprising the two termini and a non-contiguous internal sequence or a non-viral sequence, plus large D-RNAs of 10-12 kb including in their 5' proximal region the ORFs 1a and 1b, or with a 3' region homologous to the ten CTV 3' terminal ORFs, have been described [41, 43, 46, 55]. These large D-RNAs resembled the RNAs 1 and 2 distinctive of the bipartite *Criniviruses,* also included in the *Closteroviridae* family. Moreover, the D-RNA containing the complete CTV replicase constitutes a novel class of large self-replicating D-RNAs [47].

CTV D-RNAs characteristic genomic structure suggests an origin in the recombination events during viral replication. In this way, some large D-RNA bear a 5´ termini identical o slightly larger than the 5´ sgRNA generated by the CE of the p33 ORF [47], and the small ones usually contain a 3´ termini identical to 3´ sgRNA of p23 ORF [43]. Additionally, a repeated 4-5 nt, (corresponding to two CTV genomic regions) was reported flanking the D-RNA 3´ and 5´ termini junction sites indicating that D-RNAs are probably created during the generation of the positive-strand sgRNA or gRNA by a template-switching mechanism [41, 43].

D-RNAs require the viral machinery for their survival. The D-RNA replication *in trans* was examined using infectious D-RNAs and the *in vitro* genetic system of *T36/CTV9* [10, 6]. The minimal D-RNA sequence required for replication are a 5´ proximal region of 1kb and a 3´ termini limited to the CTV 3´NTR. In addition, efficient replication of D-RNAs involves some spacing between these terminal cis-acting signals and a continuous ORF through most of the 5´ proximal regions of the D-RNA sequence [10, 56]. CTV field isolates are composed by viral populations of divergent genotypes. In this case, an important point is to understand the dynamics of generation and accumulation of D-RNAs in a specific plant cell infected with distinct CTV genotypes. Mawassi et al., [56] demonstrate that some wild-type populations of CTV are capable of supporting the replication of synthetic divergent D-RNAs. However, replacement of 5´ region (which is the most variable among CTV strains) of a particular synthetic D-RNA, with the corresponding sequence from different main CTV genotypes, resulted in chimeric D-RNAs that were replicated to detectable levels by some CTV genotypes but not with the others. Consequently, differential specificities of distinct CTV replicase complexes with divergent D-RNA replication signals are possibly affecting the maintenance of D-RNA population structures in the infected plant cell.

**6.** *Citrus tristeza virus* **encapsidation**

mixed infections [59].

CTV assembly is unknown at the moment [52].

Differently of most elongated viruses, CTV particles are encapsidated by two different capsid proteins that coat the opposite ends of the virion [24]. About the 97% of the CTV genome is coated by CP, while the remainder 3% is coated by CPm resulting in viral particles with the emblematic tail of the members of the *Closteroviridae* family [11, 24]. The coordinate action of HSP70h and p61, in addition to the CP and CPm coat proteins, are required for proper assembly of CTV particles [13]. The previously described CTV 5´NTR conserved SL structures contains the origin of assembly of CPm, overlapping the sequences that function as a cis-acting element required for gRNA synthesis [24]. During CTV assembly, CPm begins coating the gRNA at the 5´ NTR to about nt 630. However, in the absence of HSP70h or p61, CPm may coat larger segments or even the complete gRNA. Probably, HSP70h or p61 bind to the transition zone between CP and CPm (around 630 nt) and restrict CPm to the virion tail [24]. The protein homologous to HSP70h and p61 in BYV are coordinately assembled with CPm in the virion structure and remain attached to the viral particles [58]. Although the assembly of HSP70h and p61 is not directly confirmed for CTV, RNA transcripts lacking one or both of these ORFs were unable to produce infective CTV virions [24]. Several strains with divergent genotypes could coexist in the same citrus cell. Analysis of the encapsidation of heterologous CPms in absence of HSP70h and p61 indicated reduction or lack of CPm assembly. Nevertheless, the presence of HSP70h and p61 restored CPm assembly to wild-type levels. This indicated that the HSP70h and p61 could play an important role facilitating heterologous CPm assembly in

The Complex Genetics of *Citrus tristeza* virus http://dx.doi.org/10.5772/56122 11

The region coated by CPm also overlaps the LMT2 5´ sgRNA (650 nts). Actually, LMT2 production is correlated to virion assembly since mutations in the 5´ NTR that abolish encapsidation also eliminate accumulation of LMT2. Although this represents the first evidence of a viral RNA processed by the assembly mechanism, the exact function of LMT2 in

In order to infect a plant, CTV needs to enter in the cell, and to overcome the constitutive and/or inducible plant defences, to re-program the plant cellular machinery for its viral multiplica‐ tion. The infection process will continue with the assembly of new viral particles that will move celltocellthroughtheplasmodesmata.Thisprocesswillbecompletedwiththevirallongdistance movement through the plant vascular structure to colonize systemically the plant. Each CTV gene product seems to have a primary genetic function required for the survival of the virus. However, there are secondary genetic interactions, which cause or trigger resistance or pathogenic responses in the citrus host [60, 61]. *Citrus* genus contains multitude of species, cultivars and intergenic hybrids, with which CTV could interact causing a range of physiologi‐ cal and biochemical responses. These could be from either pathogenic or asymptomatic phenotypes to limited or complete plant resistance [5]. Although most of these mechanisms are

**7.** *Citrus tristeza virus* **genetics and plant-host interactions**

**Figure 5.** Different species of D-RNAs in CTV populations. Top panel: graphic representation of a usual small CTV D-RNA compared with the CTV genome. Bottom panel: accumulation of CTV RNAs in bark extracts from sweet orange plants infected with three field isolates (1 to 3 lines), before (lines w) and after (lines T) aphid transmission. Northernblot hybridization performed using a single-stranded minus-sense riboprobes specific to the 3' end (left panel) and the 5´end (right panel) of the T36 genome. From Mawassi et al. [46] and Albiach-Marti et al. [45]

In other viral pathosystems, D-RNAs have the capacity of interfering with the viral replication process of their helper virus (named defective interfering (DI) RNAs), but those function was not reported for CTV [10]. Although their biological role is presently unknown, at least in one case, the presence of D-RNAs was suggested to modulate symptom development either increasing or decreasing CTV symptom expression [57]. Most of the CTV D-RNAs contain a complete region p23 and the 3´NTR [43] that is associated with SY development [20], thus they could have a role in symptom modulation. Therefore, it will be necessary to promote further research to elucidate the role of the D-RNAs (or DI-RNAs) in CTV replication or in modulation of pathogenic responses in the infected plant host.


**2. Geometry and coordinate definition for dynamic link analysis**

#### **2.1 Antenna coordinate system space vectors of interest**

**Figure 1** illustrates the antenna coordinate system space vectors of interest [5].

**3. Dynamic link calculation**

*Antenna coordinate definition.*

**Figure 2.**

*φ* ¼ 1800

stage tracking is explained below:

**165**

**3.1 Dynamic link formulas of interest**

Cone Angle ¼ 1800

EL ¼ 900 � 1800

*π* tan 2�1 UVXBD � �ð Þ SR

*Dynamic Link from Liftoff to Final Orbital Insertion for a MEO Space Vehicle*

*DOI: http://dx.doi.org/10.5772/intechopen.92462*

**3.2 Tracking signals and link analyses along the trajectory**

1 The authors would like to thank Dr. James Yoh for his derivation of these formulas.

This section provides a summary of the dynamic link model of interest [6].  For station elevation angle, either LV or SV elevation or cone angle (EL or theta or ϴ), and LV or SV clock or azimuth angle (AZ or Phi or Ф), we have1

*π* cos �1 UVZBD � �ð Þ SR

*π* cos �1 GS � SR

j j SR ,

Clock Angle ¼ Ф � Offset

As mentioned in the introduction, there are three separate tracking signals along the flight trajectory that we need to analyze ensuring that they have adequate link margins of three dB or more. Most of the present DLA covers only two stages of launch coverage and neglecting the third stage coverage. The requirement for third

j j SR in Deg (1)

j j GS ∗ j j SR in Deg (2)

UVYBD � �ð Þ SR j j SR in Deg (3)

#### **2.2 Antenna coordinate system definition**

**Figure 2** defines the antenna coordinate system used in this chapter. The azimuth (AZ or Ф) or clock angle is used in the antenna cut configuration. The elevation angle (EL or ϴ) also called as cone angle is also used in the antenna gain data file. The antenna gain is a changing variable as a function of mission elapsed time (MET). The antenna gains are used in the following dynamic links.

**Figure 1.** *Space vehicle and ground station vector definition.*

*Dynamic Link from Liftoff to Final Orbital Insertion for a MEO Space Vehicle DOI: http://dx.doi.org/10.5772/intechopen.92462*

**Figure 2.** *Antenna coordinate definition.*

payload (PL) separation from LV, using LV, to Tracking and Data Relay Satellite System (TDRSS) [1] satellite link, which is also called beyond line of sight (BLOS) link. A third SV tracking, after SV payload separation from LV, is a tracking link between SV and a ground station (GS). This third SV tracking is now added in this

*Satellite Systems - Design, Modeling, Simulation and Analysis*

The tracking link used from liftoff to the end of LOS uses a UHF noncoherent FSK signal for command and a digital FM or BPSK for tracking telemetry link as described in detail in [2]. From the end of LOS to BLOS, the tracking telemetry link is usually a BPSK or QPSK signal, using a NASA Tracking Data Relay Satellite System to relay tracking data from the LV to White Sands or Goddard ground station (WSGT/GRGT) and finally routing it to other user ground stations. After SV payload separation and orbital insertion, the SV tracking link to an Air Force Satellite Control Network (AFSCN) ground station [3] will use Space-to-Ground Link Subsystem (SGLS) or a non-SGLS (NSGLS) waveform described in [3, 4] and

in Section 3 for tracking signals along the trajectory. In the following pages, supporting link analyses for the two LV and one SV tracking stages will be

**2. Geometry and coordinate definition for dynamic link analysis**

**Figure 1** illustrates the antenna coordinate system space vectors of

**Figure 2** defines the antenna coordinate system used in this chapter. The azimuth (AZ or Ф) or clock angle is used in the antenna cut configuration. The elevation angle (EL or ϴ) also called as cone angle is also used in the antenna gain data file. The antenna gain is a changing variable as a function of mission elapsed time (MET). The antenna gains are used in the following

**2.1 Antenna coordinate system space vectors of interest**

**2.2 Antenna coordinate system definition**

chapter.

presented.

interest [5].

dynamic links.

**Figure 1.**

**164**

*Space vehicle and ground station vector definition.*