Physical mapping of Bph3, a brown planthopper resistance locus in rice

Resistance to brown planthopper (BPH), a destructive phloem feeding insect pest, is an important objective in rice breeding programs in Thailand. The broad-spectrum resistance gene Bph3 is one of the major BPH resistance genes identified so far in cultivated rice and has been widely used in rice improvement programs. This resistance gene has been identified and mapped on the short arm of chromosome 6. In this study, physical mapping of Bph3 was performed using a BC3F3 population derived from a cross between Rathu Heenati and KDML105. Recombinant BC3F3 individuals with the Bph3 genotype were determined by phenotypic evaluation using modified mass tiller screening at the vegetative stage of rice plants. The recombination events surrounding the Bph3 locus were used to identify the co-segregate markers. According to the genome sequence of Nipponbare, the Bph3 locus was finally localized approximately in a 190 kb interval flanked by markers RM19291 and RM8072, which contain twenty-two putative genes. Additional phenotypic experiment revealed that the resistance in Rathu Heenati was decreased by increasing nitrogen content in rice plants through remobilization of nitrogen. This phenomenon should be helpful for identifying the Bph3 gene

Simplified Weight Function for Calculating Stress Intensity Factor in Complicated Stress Distributions

Calculation of a stress intensity factor becomes more difficult when crack are subjected to a complicated stress distribution profile. A standard procedure called influence coefficients is inadequate, because a stress profile may not be accurately represented by a polynomial function. This paper applies a piecewise linear approximation of stress profile and a weight function method to overcome that restriction. However, the typical adopted weight function, i.e. universal weight function, is replaced by a weight function, in which its form coincides with the analytical form. Although a new weight function consists of lesser number of terms, it is proved to be accurate when applies to a cracked-cylinder problem, e.g. internal part-through circumferential crack and internal fully circumferential crack under various complicated weld residual stress profiles. Using this simpler weight function and linearized approximation scheme led to a closed-form stress intensity factor solution, which is convenient for programming

Creep Life Prediction for Hastelloy XR Using the Omega Method

This paper applies the Omega method to creep life prediction for Hastelloy XR at temperatures ranging from 850 to 950oC in an air environment. The creep data were obtained from literature. Three life prediction scenarios were studied including constant stress, constant load, and continuous monitoring where creep data is simulated for sequential acquisition. The constant stress creep data at each temperature were used to determine the Omega model parameters, and empirical equations for each parameter were developed. The predicted creep lives under constant stress were within a factor of 2 in almost all cases. For a life prediction under constant load, the actual applied stress was estimated and used in the creep constitutive equation as well as for calculating the model parameters. The predicted creep lives were also to be within a factor of 2 in almost all cases. The Omega model was found to be applicable to a continuous creep data acquisition scenario as well. An appropriate scheme for continuous monitoring scenario was suggested, and statistical analysis by the Monte Carlo simulation was demonstrated

Object-Oriented Software for Fitness-For-Service Assessment of Cracked Cylinder Based on API RP 579

Fitness-for-service assessment of a cracked component intends to evaluate its remaining strength and remaining life to support the implementation of a maintenance plan. This research aims to develop a fitness-for-service assessment software to facilitate the task. The software development process included identifying the software specifications, designing the software structure, manipulating the information from the standard for programming, the graphical user interface design, and finally verification of the software. The assessment procedure employed in this study was the third edition of the standard API RP 579. The software structure was designed using an object-oriented concept. The software can perform integrity assessment levels 1, 2, and 3 option B, leak-before-break assessment, and remaining life assessment for a cracked cylinder that has a through-thickness crack or semi-elliptical surface crack oriented in an axial or circumferential direction. The applied loads could be a nominal axial force, bending moment, and internal pressure, as well as stress profiles perpendicular to the crack plane due to mechanical, thermal, and residual stresses. Accuracy of the software was demonstrated by applying it to example problems. Some aspects of the software extensibility were conceptually discussed

Weight Functions for Edge Crack in Bilayer Material

The problem of weight functions for an edge crack in semi-infinite bilayer materials was revisited. The research aimed to develop the empirical equations for geometrical factors for reference SIFs associated with the weight functions, which covered a wider range of elastic mismatches. The weight functions in consideration covered the cases of a crack tip in a surface layer as well as in a substrate. The direct adjustment method was employed to derive the weight function coefficients. The reference SIFs for calculating the weight function coefficients were determined by finite element analysis with a systematic variation of the crack depth and the elastic mismatch parameters. The accuracies of the empirical equations for geometrical factors for the cases of a crack tip in coating and substrate were better than 1.3% and 4%, respectively. The weight functions were applied to bilayer materials with an edge crack under various crack face loading profiles. The SIFs predicted by the weight function method agreed with those from the FE method or the literature

Metal Availability and Rice Growth Under Controlled Redox Potential and pH in Acid Sulfate Soils of Thailand.

The effects of controlled pH and redox potential (Eh) conditions on transformations of several metals and their effects on rice growth were studied in laboratory microcosms using acid sulfate (Sulfic Tropaquept) and non-acid sulfate (Typic Tropaquept) soil materials from Thailand. Some microcosms were incubated at selected controlled Eh conditions (500, 250, 50, and $-150$ mV). Others were incubated at controlled pH and Eh levels (3.5, 4.5, and 5.5 and redox potential levels $\geq$500, 250, and 50 mV respectively). Acid sulfate soil-tolerant and sensitive rice varieties (IR 46 and IR 26, respectively) were used in this study. Results indicated water-soluble Fe and exchangeable Fe were inversely related to both pH and Eh, and reducible Fe was positively related. Redox potential and pH had the same effect on water-soluble Mn as Fe. However, Eh had less of an effect on Mn than on Fe. Water-soluble Al and percent Al saturation of the CEC was negatively related to pH in both soil types under controlled pH and Eh conditions, but was negatively related to pH in only acid sulfate soils under controlled Eh conditions. Aluminum activity was negatively correlated with pH in both soil types and over all controlled conditions. Rice uptake of Fe increased with decreasing Eh and pH. Iron uptake was significantly correlated with water-soluble Fe, Fe\sp{2+} activity, and E\sp\prime-Fe. The IR 26 accumulated Fe more than the IR 46. The Mn content in shoot tissue was positively correlated with Eh and pH. Iron possibly had an antagonist effect on Mn uptake. Aluminum uptake of both rice varieties correlated best with Al\sp{3+} activity in both soil types under controlled Eh conditions. Under controlled pH and Eh conditions, IR 26 uptake of Al was positively related to percent Al saturation of the CEC in only acid sulfate soils whereas no relationship was observed for IR 46 uptake of Al in both soil types. In general, growth of rice was negatively related to the Fe:Mn ratio in shoot tissue and Al\sp{3+} activity but positively related to pe + pH and Zn\sp{2+} activity. Iron solubility was probably controlled by amorphous Fe(OH)\sb3 at high pe + pH and goethite at low pe + pH levels. Manganese solubility was regulated by cation exchange processes. Jurbanite and amorphous Al(OH)\sb3 may control Al solubility at low and high pH conditions, respectively

Effect of Thickness Eccentricity on the Stress Intensity Factors for a Pipe with a Single Internal Radial Crack under Internal Pressure

The thickness eccentricity of a pipe occurs due to manufacturing limitations and may be exacerbated by service-induced degradation mechanisms. Fracture and remaining life assessments of a cracked eccentric pipe require a solution for the crack-tip parameters, e.g., the stress intensity factors (SIFs). However, the SIFs for this problem have not been examined. This study aimed to develop SIFs for an eccentric pipe with an infinitely longitudinal crack nucleated from an inner wall at the thinnest location of the pipe cross-section subjected to internal pressure. The problem was simplified to a cracked eccentric ring in a plane-strain condition, and finite element analysis was utilized for the determination of the SIFs, which were presented in tabulated form and empirical relation. The SIFs included a wide range of configuration parameters, i.e., a thin to thick-walled pipe, a shallow to deep crack, and a concentric pipe to a pipe with moderate thickness eccentricity. The need to consider the effect of eccentricity in SIFs calculation increased when the relative thickness of a pipe decreased and the relative crack depth increased

An Improved Finite-Time Stability and Stabilization of Linear System with Constant Delay

Practical systems in engineering fields often require that values of state variables, during the finite-time interval, must not exceed a certain value when the initial values of state are given. This leads us to investigate the finite-time stability and stabilization of a linear system with a constant time-delay. Sufficient conditions to guarantee the finite-time stability and stabilization are derived by using a new form of Lyapunov-Krasovskii functional and a desired state-feedback controller. These conditions are in the form of LMIs and inequalities. Two numerical examples are given to show the effectiveness of the proposed criteria. Results show that our proposed criteria are less conservative than previous works in terms of versatility of minimum bounds and larger bounds of time-delay

Available cloned genes and markers for genetic improvement of biotic stress resistance in rice

Biotic stress is one of the major threats to stable rice production. Climate change affects the shifting of pest outbreaks in time and space. Genetic improvement of biotic stress resistance in rice is a cost-effective and environment-friendly way to control diseases and pests compared to other methods such as chemical spraying. Fast deployment of the available and suitable genes/alleles in local elite varieties through marker-assisted selection (MAS) is crucial for stable high-yield rice production. In this review, we focused on consolidating all the available cloned genes/alleles conferring resistance against rice pathogens (virus, bacteria, and fungus) and insect pests, the corresponding donor materials, and the DNA markers linked to the identified genes. To date, 48 genes (independent loci) have been cloned for only major biotic stresses: seven genes for brown planthopper (BPH), 23 for blast, 13 for bacterial blight, and five for viruses. Physical locations of the 48 genes were graphically mapped on the 12 rice chromosomes so that breeders can easily find the locations of the target genes and distances among all the biotic stress resistance genes and any other target trait genes. For efficient use of the cloned genes, we collected all the publically available DNA markers (~500 markers) linked to the identified genes. In case of no available cloned genes yet for the other biotic stresses, we provided brief information such as donor germplasm, quantitative trait loci (QTLs), and the related papers. All the information described in this review can contribute to the fast genetic improvement of biotic stress resistance in rice for stable high-yield rice production

Emergency medical dispatch services across Pan-Asian countries: a web-based survey

Background Dispatch services (DSs) form an integral part of emergency medical service (EMS) systems. The role of a dispatcher has also evolved into a crucial link in patient care delivery, particularly in dispatcher assisted cardio-pulmonary resuscitation (DACPR) during out-of-hospital cardiac arrest (OHCA). Yet, there has been a paucity of research into the emerging area of dispatch science in Asia. This paper compares the characteristics of DSs, and state of implementation of DACPR within the Pan-Asian Resuscitation Outcomes (PAROS) network. Methods A cross-sectional descriptive survey addressing population characteristics, DS structures and levels of service, state of DACPR implementation (including protocols and quality improvement programs) among PAROS DSs. Results 9 DSs responded, representing a total of 23 dispatch centres from 9 countries that serve over 80 million people. Most PAROS DSs operate a tiered dispatch response, have implemented medical oversight, and tend to be staffed by dispatchers with a predominantly medical background. Almost all PAROS DSs have begun tracking key EMS indicators. 77.8% (n = 7) of PAROS DSs have introduced DACPR. Of the DSs that have rolled out DACPR, 71.4% (n = 5) provided instructions in over one language. All DSs that implemented DACPR and provided feedback to dispatchers offered feedback on missed OHCA recognition. The majority of DSs (83.3%; n = 5) that offered DACPR and provided feedback to dispatchers also implemented corrective feedback, while 66.7% (n = 4) offered positive feedback. Compression-only CPR was the standard instruction for PAROS DSs. OHCA recognition sensitivity varied widely in PAROS DSs, ranging from 32.6% (95% CI: 29.9–35.5%) to 79.2% (95% CI: 72.9–84.4%). Median time to first compression ranged from 120 s to 220 s. Conclusions We found notable variations in characteristics and state of DACPR implementation between PAROS DSs. These findings will lay the groundwork for future DS and DACPR studies in the PAROS network.This study was supported by grants from National Medical Research Council, Clinician Scientist Awards, Singapore NMRC/CSA/024/2010 and NMRC/CSA/0049/2013), Ministry of Health, Health Services Research Grant, Singapore (HSRG/0021/2012). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript