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Digital Logic, Arithmetic, and Conversions
Published in Julio Sanchez, Maria P. Canton, Microcontroller Programming, 2018
Julio Sanchez, Maria P. Canton
Observing the carry into and the carry out of the most significant bit is a valid way of detecting overflow of a two’s complement arithmetic operation. In theory, the logic described in the flowchart of Figure 4-7 can be implemented in devices without hardware support for signed overflow; however, the processing is complicated and therefore costly in execution time. An alternative approach is to ensure that the format has sufficient capacity to store the arithmetic result. The rule developed previously lets us determine that, for addition and subtraction, the destination format must have at least one more byte than the operands. In multiplication, the destination operand must be at least twice the size of the source operands.
Gate-Level Modeling
Published in Joseph Cavanagh, ® HDL Digital Design and Modeling, 2017
Example 5.11 A full adder will now be designed using built-in primitives with propagation delays assigned to the gates. This will be a high-speed full adder using a sumof-minterms format. A full adder is a combinational circuit that computes the sum of two operand bits plus a carry-in bit. The carry-in signal represents the carry-out of the previous lower-order bit position. The full adder produces two outputs: a sum bit and a carry-out bit. The truth table for a full adder is shown in Table 5.7. sum=a'b'cin+a'bcin'+ab'cin'+abcincarry-out=a'bcin+ab'cin+abcin'+abcin=ab+acin+bcin
A Comprehensive Literature of Genetics Cryptographic Algorithms for Data Security in Cloud Computing
Published in Cybernetics and Systems, 2023
Ozgu Can, Fursan Thabit, Asia Othman Aljahdali, Sharaf Al-Homdy, Hoda A. Alkhzaimi
A chromosome is a DNA and protein strand in the nucleus of living organisms that carry genetic information in the form of genes. As a natural transporter of information, DNA may be employed in a variety of ways to ensure information security. The order of bases along a DNA strand forms a code or information for making proteins. As shown in Figure 4, the components of genetics in DNA and RNA are used to create the Genetic Algorithm as follows: Encoding schemes, Creation, Fitness Evaluation, Selection, Reproduction, Crossover, Inversion, Mutation, Elitism, and Stopping Criteria. Each DNA molecule contains these elements in a random order, and the distribution of these nucleotides determines DNA's genetic code. The power of any genetic scheme is directly correlated with the randomization it provides. According to researchers, the nucleotide sequence’s randomization can be effectively used to design a strong and dependable coding scheme. Using fundamental DNA to enhance coding systems is not feasible due to complicated laboratory requirements (Maniyath and Kaiselvan 2016).
Investigation of associations between exposures to pesticides and testosterone levels in Thai farmers
Published in Archives of Environmental & Occupational Health, 2018
Parinya Panuwet, Chandresh Ladva, Dana Boyd Barr, Tippawan Prapamontol, John D. Meeker, Priya Esilda D'Souza, Héctor Maldonado, P. Barry Ryan, Mark G. Robson
Generally, PON1 plays an important role in the mechanism of some OP toxicity, influencing susceptibility or protecting humans and other mammals from toxicity or disease.44 PON1, which is produced by the cytochrome P-450 enzyme in the liver, is an enzyme that detoxifies the active forms (oxon metabolites)45 of a number of OP insecticides.44 The three distinct PON1*192 genotypes (QQ, QR, and RR) were reported to have different influences on the rates of hydrolysis of, for example, paraoxon and chlorpyrifos oxon, in which the RR genotype contributes the highest enzymatic activity.45 The existence of the PON1*55 polymorphism, on the other hand, controls the extent of PON1 expression. In most cases, the expression of PON1*55M has been shown to decrease serum enzyme concentrations.44 Thais, Mexicans, Chinese, Japanese, and Caucasian Americans all have the *192R allele available in different degrees of abundance.46 For the *192R allele, Thais were reported to have approximately 29%–61% frequency,47,48 while about 49%–60% frequency was found in Mexicans.49,50 Approximately 29%–31% of Caucasian Americans were reported to carry the *192R allele.46 For the *55 M allele, Thais had a 5%–6% frequency47,48 compared to 6%–16% in Mexicans.49,50 In Caucasian Americans, 36% of the population carry the *55 M allele.46
Agricultural production: assessment of the potential use of Cas9-mediated gene drive systems for agricultural pest control
Published in Journal of Responsible Innovation, 2018
Maxwell J. Scott, Fred Gould, Marcé Lorenzen, Nathaniel Grubbs, Owain Edwards, David O’Brochta
Insecticides, and to a lesser extent biological control (parasitoids), have been used to control many species of Hemiptera. The plant-feeding habits of many of these insects make it likely that future population control strategies are likely to include the use of plant-based systemic RNA interference (RNAi) to some extent (Upadhyay et al. 2011). Basic functional genomics tools still need to be developed for many of these species to aid in identifying genes that can act as targets for plant-based gene silencing strategies. Genomic studies that elucidate the physiological genetics of Hemipterans will be important in designing and producing plants that are resistant to these insects and the diseases they carry. In particular, plant-feeding Hemiptera act as vectors of plant pathogenic viruses through a variety of mechanisms. Some insects essentially only serve as physical carriers of viruses; viruses simply attach to specialized regions of their mouthparts. In other cases, viruses infect the insect, in ways that may or may not involve viral replication, and then circulate within the insect (Whitfield, Falk, and Rotenberg 2015). The high degree of specificity involved with these virus/insect interactions involves a number of insect proteins and genes. However, in most cases, validating the function of these proteins/genes has been difficult because of the absence of genetic technologies that allow for rigorous testing of structure/function relationships. Consequently, there has been no confirmed identification of insect receptor proteins responsible for specific interactions with circulative viruses (Blanc, Drucker, and Uzest 2014). Thus, without a better molecular understanding of virus-host interactions it will be difficult to develop plant-resistance mechanisms or gene-drive systems that will inhibit viral transmission. Further, multiple anti-pathogen genes would need to be developed for species such as B. tabaci that are vectors for several viruses. For these species, a population suppression strategy is more feasible. While RNAi-based gene downregulation, through ingestion or injection, has proven highly effective in several species of Hemipterans, including Acyrthosiphon pisum, Lygus lineolaris, Oncopeltus fasciatus, Rhodnius prolixus, N. lugens, and B. tabaci (You et al. 2013), more sophisticated genetic manipulations involving both gene knockout and transgenic technologies are needed for the types of genetic experiments required to validate putative virus-receptor proteins in these insects.