DETERMINE评分与急性心肌梗死PCI术预后关系的分析

探讨DETERMINE评分(病理性Q波导联数*2+碎裂QRS波导联数+T波倒置导联数)与急性心肌梗死患者经皮冠状动脉介入(PCI)术后预后的关系。方法 选择2021.1-2022.12在我院住院接受PCI治疗的急性心肌梗死患者206例,根据预后情况分为预后良好组(165例)和预后不良组(41例)。比较两组患者的临床资料及DETERMINE评分,采用多因素Logistic回归法分析影响急性心肌梗死PCI术后预后的相关因素;创建受试者工作特征曲线(ROC),分析DETERMINE评分对急性心肌梗死PCI术后预后的预测价值。分析急性心肌梗死PCI术预后不良的影响因素。结果 与预后良好组比较,预后不良组糖尿病史、心律失常史比例及DETERMINE评分、年龄、体重指数、左室射血分数、糖化血红蛋白、低密度脂蛋白胆固醇、总胆固醇水平均显著升高,差异具有统计学意义;二元Logistic回归分析显示DETERMINE评分、心律失常史、体重指数、糖化血红蛋白、低密度脂蛋白胆固醇是冠心病患者PCI手术预后不良的独立危险因素(OR=1.443~15.658,P<0.05)。结论 DETERMINE评分与冠心病PCI术预后相关,需引起临床关注。

Determined Reverberant Blind Source Separation of Audio Mixing Signals

Audio signal separation is an open and challenging issue in the classical“Cocktail Party Problem”.Especially in a reverberation environment,the separation of mixed signals is more difficult separated due to the influence of reverberation and echo.To solve the problem,we propose a determined reverberant blind source separation algorithm.The main innovation of the algorithm focuses on the estimation of the mixing matrix.A new cost function is built to obtain the accurate demixing matrix,which shows the gap between the prediction and the actual data.Then,the update rule of the demixing matrix is derived using Newton gradient descent method.The identity matrix is employed as the initial demixing matrix for avoiding local optima problem.Through the real-time iterative update of the demixing matrix,frequency-domain sources are obtained.Then,time-domain sources can be obtained using an inverse short-time Fourier transform.Experi-mental results based on a series of source separation of speech and music mixing signals demonstrate that the proposed algorithm achieves better separation performance than the state-of-the-art methods.In particular,it has much better superiority in the highly reverberant environment.

Determinants of Modern Contraceptive Uptake among the Youth in Akuse Township in the Lower Manya Krobo Municipality, Ghana

Background: Access to safe and effective contraception is crucial for sexual and reproductive health to be at its best. This allows improved pregnancy results and the avoidance of unintended births. Teenagers’ views on using contraceptives are influenced by the information available at their disposal. The study assessed the influential factors affecting the utilization of modern contraceptives among the youth in Akuse in the Eastern Region of Ghana. Methods: The data for the study were gathered from 378 consented youth aged 15 - 24 years using a quantitative cross-sectional study design and a well-structured questionnaire. Person’s Chi-Square test was adopted to measure the association between the outcome variable and selected independent variables. Logistic regression models were utilized to measure the odds of the factors influencing modern contraceptive use among the respondents. Results: The results of the study suggested a high knowledge level of contraceptives;however, the prevalence of utilization was low. The level of education and age were factors found to influence the uptake of contraceptives. A bivariate analysis to examine the association between selected socio-demographic variables revealed that educational level (p = 0.044), religious affiliation (p = 0.002), and ethnicity (p = 0.016) were statistically associated with modern contraceptive use among the respondents. All other tested demographic variables including the age groups, gender, marital status, and residential status proved otherwise at the observed p-values greater than the 0.05 threshold. Respondents who indicated staying with partners were 6.79 times more likely to use contraceptives compared to their counterparts staying with a parent, after controlling for all other covariates. Conclusions: Based on the findings of this study, it was concluded that high contraceptive knowledge influences the choice of contraceptive preferred by the youth, and contraceptive use is also influenced by the advancement in age and educational level of the youth. It is however recommended that parents, guidance, and teachers be entreated to offer relevant and timely sexual information or education as these will most likely improve the uptake of modern contraceptives among the targeted population.

Sex Determination in Homo sapiens as a Multi-Step Process: Potential for Development of Variants and Sex Differences in Disease Risk

Reproduction via cis-binary mechanisms appears to have evolved fairly early in the evolution of complex organisms, and a system committed to prior to evolution of humans. While the evolution of a chromosomal-specific approach has been a successful strategy for survival of a large variety of species including humans, the fidelity of sex determination leading to 100% cis-binary outcomes is not achieved in many species, with evidence for homosexual or bisexual behaviour evident in more than 1500 species. Thus, such outcomes indicates that sex determination is a multi-step process and not a single event, and as such, could lead to the appearance of variants during the process which developed much earlier than humans. Variants could arise either due to intrinsic variation in the steps of determination, or also be influenced by environmental factors of a biological or psychological nature. In contrast to homosexual variants which do not require interventions such as hormone therapy or surgery, expression of gender dysphoria, is more based in psychology, but also has biological underpinnings and can be influenced by such hormonal interventions and surgery. While the numbers of those with gender dysphoria is small (~0.6% - 1.0% of population), the attention given to this issue raises the possibility of biological and psychological environmental factors impacting the emergence of some of those expressing gender dysphoria. Furthermore, transitioning from male-to-female or female-to-male can have consequences regarding disease risks latter in life, including the appearance of autoimmune diseases. This review will attempt to review some of the evidence regarding sex determination, discuss why the system has potentially not been improved upon during evolution, how a potential role for sex chromosome function on neurodevelopment may be central to variation in humans, and how commitment to the current strategy is likely integrated into other sex-related events such as puberty, pregnancy, and menopause to ensure species survival. It will also discuss how variants in sex determination could contribute to sex differences in disease risk and how epigenetic modifications could play a role in such risk. .

Rabies by Dog Bites in Benin: Determinants of Good Knowledge of the Rabies Risk among Subjects Exposed in the Plateau Department in 2023

Rabies, a viral zoonosis, is one of the neglected tropical diseases (NTDs) that mainly affects poor and vulnerable populations. Human rabies is endemic in Benin. Although listed among the notifiable diseases, it nevertheless remains a neglected and under-reported disease. The objective of this study was to investigate the determinants of knowledge of rabies risk among subjects exposed to human rabies by dog bites in the Plateau department of Benin. Methods: This was a cross-sectional study with an analytical aim which involved a sample of 900 people aged at least 18 years old chosen randomly and residing in the Plateau department for at least six months. A pre-tested and validated digital questionnaire served as a data collection tool. Data analysis was done with R 3.4.1 software. The prevalence ratio was used as a measure of association. The confidence threshold was set at 5%. We carried out a multiple logistic regression using the likelihood ratio (top-down approach) in order to identify the main factors which influenced the good knowledge of human rabies in the population of Plateau. Results: In the study population, 80.89% of the subjects surveyed lived in a rural area. The sex ratio (Male/Female) was 1.11. The average age of the subjects was 40.24 ± 14.52 years. The prevalence of dog bites was 4.11% (95% CI = [3.00;5.63]) or 37 subjects bitten. After evaluation of knowledge of rabies risk in the study population, the main factors which positively influenced good knowledge of human rabies were age (p linear trend 0.01), residence of the subject in the municipality of Pobè (ORa = 8.34;95% CI = 0.83 - 1.23;p < 0.01), individual dwelling (ORa = 17.95;95% CI = 13.12 - 49.58;p < 0. 01), educational level of at least secondary (ORa = 5.53;CI 95 = 3.06 - 10.15;p = 0.01), the existence of a veterinary center (ORa = 3.66;CI 95 = 1.07 - 12.43 p = 0.01) and knowledge of a dog bites victim (ORa = 6.55;95% CI = 2.73 - 8.25;p < 0.01). Conclusion: This population study confirms that human rabies remains a public health problem with a need to raise awareness among populations on good prevention practices against human rabies after a dog bite in the Plateau department. This could help to improve strategies surveillance for the control and eradication of human rabies through the implementation of the One Health approach.

Unintended Pregnancy Determinants among Antenatal Clinic Attendees: A University of Port Harcourt Teaching Hospital Experience

An unintended pregnancy is a pregnancy that is either mistimed or unplanned. The objectives of this study were to determine the prevalence of unintended pregnancy as well as to document the determinant factors among pregnant women attending antenatal clinics at the University of Port Harcourt Teaching Hospital (UPTH), Port Harcourt, Rivers State, Nigeria. It was a descriptive, cross-sectional study of 215 women attending the antenatal clinic of UPTH from July to August 2022. Information on socio-demographic characteristics, reproductive history, desirability of the current pregnancy at the time of conception, knowledge and use of contraceptive methods were collected using a pretested questionnaire and analyzed using SPSS version 26.0. Chi-square test was used for test of associations with the level of significance set at P < 0.05. The prevalence rate of unintended pregnancy from the study was 16.28% (≈16%). The contraceptive awareness was very high (209, 97.21%), however, 101 (46.98%) participants had never used any form of contraceptives. Univariate analysis using Chi-square test showed a statistically significant association between age and unintended pregnancy (P = 0.042), level of education and unwanted pregnancy (P = 0.033) as well as parity and unintended pregnancy (P = 0.019). The prevalence of unintended pregnancy among women attending antenatal clinics was high, possibly due to low contraceptive usage. More efforts should be geared towards ensuring access to comprehensive contraceptive care and contraceptive methods, this will enhance uptake and reduce the rate of unintended pregnancy.

Determinants of Early Survival of Breast Cancer Patients in Yaoundé-Cameroon

Introduction: Breast cancer is one of the leading causes of death worldwide. We carried out this study with the aim of evaluating the determinants of early survival of women with breast cancer in two hospitals in the city of Yaoundé. Methodology: This was an analytical cross-sectional study with retrospective and prospective data collection of breast cancer patients during 6 years in two Hospitals of Yaoundé from January 2017 to December 2022. We consulted the files in search of epidemiological, clinical, paraclinical, therapeutic and survival variables. We completed the survival data directly from the patients or their relatives after their consent. We analyzed the data using SPSS version 23.0 software. Survival analysis was done using the Kaplan-Meier method and survival curves were compared using the Log Rank test. Factors influencing survival were evaluated using the Cox model. The significance threshold (P value) was set at 0.05 at 95% confidence interval. The study was approved by the ethics committees. Results: We included 500 patients whose ages varied between 22 and 83 years with a mean age of 47.19 ± 11.61 years. The most represented age group was 30 to 45 years old (45.8%). Less than half (41.6%) were postmenopausal. The most frequent reason for consultation was a breast lump (79.9%). The most common clinical stage at presentation was stage-3 (47.6%). Infiltrating ductal carcinoma was the most represented histological type (84.7%). The most represented histological grade was grade 2 (40.2%). Immunohistochemistry was performed in 34.20% of cases. The most represented molecular subtype was triple negative (41.8%) followed by Luminal A (30%). Concerning treatment, 17.2% did not receive any, 45% had surgery, 79.4% had chemotherapy, 34.2% hormone therapy, and 14.6% radiotherapy. The survival of patients with breast cancer at 1, 2, 3, 4 and 5 years was respectively 90.6%;83.1%;74.2%;69.8% and 59.2%. The median survival was not reached;however, the first quartile (Q1) was 36 months (3 years). Independent factors associated with reduced survival were breast ulceration (aHR = 3.23;p = 0.002), bilateral tumor location (aHR = 9.2;p < 0.001) and clinical stage 3 (aHR = 1.72;p = 0.010) while patients classified ACR3 on imaging (aHR = 0.19;p = 0.005) had improved survival. Conclusion: Breast cancer survival from 1 to 5 years decrease from 90 to 59%. Mortality was highest in the first 40 months. Independent factors associated with reduced survival were breast ulceration, bilateral tumor location and clinical stage 3 while patients classified ACR3 on imaging had improved survival.

Silencing transformer and transformer-2 in Zeugodacus cucurbitae causes defective sex determination with inviability of most pseudomales

transformer is a switch gene for sex determination in many insects, which cooperates with transformer-2 that is expressed in both sexes to regulate female differentiation, particularly in dipterans. Zeugodacus cucurbitae(Coquillett) is a very destructive pest worldwide, however, its sex determination pathway remains largely uncharacterized. Here, we show that the female sex ratio is sharply reduced with knockdown of either transformer or transformer-2 by RNA interference in early embryos of Z. cucurbitae. Most of the males grown from the embryos with transient transformer and transformer-2 suppression mated with wild-type females and produced mixed sex progeny, with one exception that produced only female progeny, and all of the few remaining males failed to mate with wild-type females and produced no progeny. The exceptional male and those males with mating failure were XX pseudomales as determined by the detection of Y chromosome-linked Maleness-on-the-Y, indicating that most XX pseudomales are not viable. The phenotypes of transformer and transformer-2 suggest that they play a key role in regulating sex determination and are required for female sexual development of Z. cucurbitae. Our results will be beneficial to the understanding of sex determination in Z. cucurbitae and can facilitate the development of genetic sexing strains for its biological control.

Rationale of a Cross Sectional Analytic Study on Determinants of Recurrent Preeclampsia at University Clinics of Kinshasa (Democratic Republic of Congo) and at Victor Dupouy Hospital Center (France)

Research Background: Pre-eclampsia is one of main causes of materno-foetal mortality and morbidity worldwide, with a prevalence of 3% - 7%. Although considered a primiparous condition, it can nevertheless recur. Several factors appear to be associated with risk of recurrence of pre-eclampsia, such as the term of delivery of previous pregnancy, severity of disease, the existence of co-morbidities and the inter-genital space. Purpose: The aim of our study will be to analyse and identify in a population of pregnant women with a history of preeclampsia risk factors associated with occurrence of recurrent preeclampsia at University clinics of Kinshasa (Democratic Republic of Congo) and at Victor Dupouy Hospital Center (France). Methods: In this study, pregnant women with an history of preeclampsia who will give birth between November 2018 and October 2024 at University Clinics of Kinshasa (UCK) and Victor Dupouy Hospital Center (VDHC) will be included. This will be a cross-sectional analytical study, data from previous and subsequent pregnancies will be studied. Expected Result: The prevalence of recurrent preeclampsia in the study population will be determined. And we will highlight the factors that will determine the recurrence of preeclampsia by analysing the risk factors. Conclusion: Knowledge of the factors associated with recurrent preeclampsia could be an excellent tool for predicting and preventing the disease.

Determining the observation epochs of star catalogs from ancient China using the generalized Hough transform method

Ancient China recorded a wealth of astronomical observations,notably distinguished by the inclusion of empirical measurements of stellar observations.However,determining the precise observational epochs for these datasets poses a formidable challenge.This study employs the generalized Hough transform methodology to analyze two distinct sets of observational data originating from the Song and Yuan dynasties,allowing accurate estimation of the epochs of these stellar observations.This research introduces a novel and systematic approach,offering a scholarly perspective for the analysis of additional datasets within the domain of ancient astronomical catalogs in future investigations.

Research Progress on Purification Process, Content Determination and Pharmacological Action of Atractylodin

Atractylodis Rhizoma comes from the dry rhizome of Atractylis lancea or Atractylodes chinensis in the Compositae family,and it is suitable for preventing and treating diseases such as cold,edema,night blindness and rheumatic arthralgia.Atractylodin is the main active component extracted and isolated from Atractylodis Rhizoma.A large number of studies have found that atractylodin has excellent drug activity in improving gastrointestinal emptying,anti-inflammation,inhibiting malignant tumor and reducing blood lipid.In this paper,the purification process and pharmacological activity of Atractylodin were summarized to provide a theoretical basis for basic research,clinical application and further development and utilization of atractylodin.

Determinants of Tobacco Cultivation and the Associated Impacts of Adoption in Hurungwe District, Zimbabwe

Tobacco is an essential cash crop in Zimbabwe and a strategic livelihood option for hundreds of thousands of rural households. However, the crop is linked to negative environmental, economic, and social impacts. The existing studies on tobacco cultivation in Zimbabwe present contradictory findings on the determinants and impacts of adoption, leaving unanswered questions about the crop’s sustainability impact in the country. This article investigates the determinants of smallholder farmers’ decisions to grow tobacco and the associated impacts of adoption. Random and purposive sampling were used to select 273 household surveys, including tobacco and non-tobacco smallholder farmers, and 56 expert interviews to answer the research questions. We employed regression models alongside expert interviews and document analysis to identify the determinants influencing the decision-making process of smallholder farmers in Zimbabwe regarding tobacco cultivation. Additionally, our investigation aimed to elucidate the perceived impacts associated with the adoption of this agricultural practice. The regression analysis indicated that the farmer’s age, education level, farming experience, family size, household income, and perceived high farm profitability are significant drivers of tobacco adoption. We also discovered divergent and convergent perceptions of the critical impacts of tobacco cultivation. The study highlights the need for proactive multi-stakeholder collaboration and sustainable financial arrangements to address the negative impacts of tobacco production. As the primary stakeholder responsible for regulating and promoting agricultural activities, the Zimbabwean government should provide meaningful financial support, increase access to credit, and ensure better market facilities for alternative crops to reduce the over-dependence on tobacco.

Impact of Social Determinants of Health on Self-Perceived Resilience: An Exploratory Study of Two Cohorts of Adults with Congenital Heart Disease

Social determinants of health(SDOH)affect quality of life.We investigated SDOH impacts on self-perceived resilience among people with adult congenital heart disease(ACHD).Secondary analysis of data from two com-plementary studies:a survey study conducted May 2021–June 2022 and a qualitative study conducted June 2020–August 2021.Resilience was assessed through CD-RISC10 score(range 0–40,higher scores reflect greater self-perceived resilience)and interview responses.Sociodemographic and SDOH(education,employment,living situa-tion,monetary stability,financial dependency,area deprivation index)data were collected by healthcare record review and self-report.We used linear regression with robust standard errors to analyze survey data and performed a thematic analysis of interview data.Survey participants(N=127)mean age was 42±14 years;51%were female,87%white.ACHD was moderate(75%)or complex(25%);41%functional class C or D.Resilience(mean 30±7)varied by monetary stability:compared to people with difficulty paying bills,resilience was 15.0 points higher(95%CI:6.9–23.1,p<0.001)for people reporting having enough money and 14.2 points higher(95%CI:5.9–22.4,p=0.001)for those reporting just enough money.Interview participants’(N=25)mean age was 32 years(range 22–44);52%were female,72%white.ACHD was moderate(56%)or complex(44%);76%functional class C or D.Participants discussed factors affecting resilience aligned with each of the major SDOH,prominently,economic stability and healthcare access and quality.Financial stability may be important for supporting self-perceived resi-lience in ACHD.This knowledge can inform the development of resilience interventions for this population.

Determination of Chlorogenic Acid,Geniposide,Total Flavonoids and Total Triterpenes in Wulan-13

[Objectives]This study was conducted to establish a method for the determination of chlorogenic acid,geniposide,total flavonoids and total triterpenes in Wulan-13.[Methods]The contents of chlorogenic acid and geniposide were determined by HPLC,and the contents of total flavonoids and total triterpenes were determined by an ultraviolet spectrophotometer.[Results]There was a good linear relation between the mass of chlorogenic acid reference substance and the peak area in the range of 0.05-0.45μg,and the regression equation was Y=2524.1X+3.1943,(r=0.9998).A good linear relationship was found between the mass of gardenoside reference substance and the peak area in the range of 0.776-6.984μg,and the regression equation was Y=1670.5X+64.804,(r=0.9998).There was also a good linear relation between the mass of rutin reference substance and its absorbance in the range of 0.00808-0.04848 mg,and the regression equation was Y=12.916X+0.014,(r=0.999).The mass of oleanolic acid reference substance had a good linear relation with its absorbance in the range of 0.00418-0.0209 mg,and the regression equation was Y=51.89X-0.0839,(r=0.9991).[Conclusions]The content determination method is simple,reliable and reproducible,and suitable for controlling the contents of chlorogenic acid,geniposide,total flavonoids and total triterpenes in Wulan-13.

TLC Identification of Yao Medicine Pileostegia tomentellal and Extraction Technology and Content Determination of Umbelliferone

[Objectives]To establish a TLC and content determination method of Pileostegia tomentellal,with umbelliferone as the indicator component.[Methods]TLC identification was performed by silica gel G thin layer plate with n-hexane-ethyl acetate(4:3)as the developing agent,and the plate was examined by UV lamp(365 nm).The umbelliferone content was determined by HPLC:Inertsil ODS-3 C 18 column(4.60 mm×250 mm,5μm);mobile phase acetonitrile-0.2%phosphoric acid gradient elution;detection wavelength 320 nm,flow rate 1.0 mL/min,column temperature 30℃,injection volume 10μL.[Results]The chromatogram of P.tomentellal showed the same color spot in the same position as that of reference medicinal material,and the spot was clear with good specificity.Umbelliferone showed a good linear relationship when the injection volume was 2.63-131.27μg/mL(R^(2)=0.9997).The average recovery of umbelliferone in the low,middle and high adding groups of P.tomentellal was 99.57%and the RSD was 2.15%.[Conclusions]The method can effectively identify Yao medicine P.tomentellal and accurately determine the content of umbelliferone in medicinal materials,which will provide a scientific basis for the development and utilization of medicinal resources of Yao medicine P.tomentellal.

Frequentist and Bayesian Sample Size Determination for Single-Arm Clinical Trials Based on a Binary Response Variable: A Shiny App to Implement Exact Methods

Sample size determination typically relies on a power analysis based on a frequentist conditional approach. This latter can be seen as a particular case of the two-priors approach, which allows to build four distinct power functions to select the optimal sample size. We revise this approach when the focus is on testing a single binomial proportion. We consider exact methods and introduce a conservative criterion to account for the typical non-monotonic behavior of the power functions, when dealing with discrete data. The main purpose of this paper is to present a Shiny App providing a user-friendly, interactive tool to apply these criteria. The app also provides specific tools to elicit the analysis and the design prior distributions, which are the core of the two-priors approach.

Determination of Salvianolic Acid B in Yiqi Huayu Prescription by HPLC

[Objectives]To determine the content of salvianolic acid B in Yiqi Huayu Prescription by HPLC.[Methods]The chromatographic column was ZORBAX Eclipse Plus C 18(4.6 nm×250 nm,5μm);the mobile phase was acetonitrile-0.1%phosphoric acid(21:79),the detection wavelength was 286 nm,the column temperature was 30℃,and the flow rate was 1.0 mL/min.A method for determination of salvianolic acid B in Yiqi Huayu Prescription was established.[Results]The linear relationship of salvianolic acid B was good in the range of 0.0214-0.4064 mg/mL.The regression equation was Y=5995.98984 X-0.07332,r=0.9999.The average recovery rate was 98.88%(RSD=1.6%).[Conclusions]The method is reliable,accurate and specific,and can be used for the determination of salvianolic acid B in Yiqi Huayu Prescription.

Sociodemographic determinants associated with breastfeeding in term infants with low birth weight in Latin American countries

BACKGROUND A progressive decrease in exclusive breastfeeding(BF)is observed in Latin America and the Caribbean compared with global results.The possibility of being breastfed and continuing BF for>6 months is lower in low birth weight than in healthy-weight infants.AIM To identify factors associated with BF maintenance and promotion,with particular attention to low-and middle-income countries,by studying geographic,socioeconomic,and individual or neonatal health factors.METHODS A scoping review was conducted in 2018 using the conceptual model of social determinants of health published by the Commission on Equity and Health Inequalities in the United States.The extracted data with common characteristics were synthesized and categorized into two main themes:(1)Sociodemographic factors and proximal determinants involved in the initiation and maintenance of BF in low-birth-weight term infants in Latin America;and(2)individual characteristics related to the self-efficacy capacity for BF maintenance and adherence in low-birth-weight term infants.RESULTS This study identified maternal age,educational level,maternal economic capacity,social stratum,exposure to BF substitutes,access to BF information,and quality of health services as mediators for maintaining BF.CONCLUSION Individual self-efficacy factors that enable BF adherence in at-risk populations should be analyzed for better health outcomes.

What determines irrigation efficiency when farmers face extreme weather events? A field survey of the major wheat producing regions in China

Water availability is a major constraint on grain production in China, therefore, improving irrigation efficiency is particularly important when agriculture faces extreme weather events. This paper first calculates irrigation efficiency with a translog stochastic frontier production function and then investigates what happens when extreme weather events occur via a Tobit model. The estimated results reveal several important features of irrigation practices: i) irrigation efficiency is lower when extreme weather events occur; ii) large variations in irrigation efficiency occur across irrigation facilities; iii) the farm plots exhibit an extreme distribution across efficiency levels; and iv) water-saving techniques, technology adoption, and the maintenance of farmers’ economic resilience are major determinants of irrigation efficiency. Based on these results we propose the following recommendations: i) farmers should balance crop yield and water use; undertake relevant training programs and adopt water-saving techniques; ii) local governments and researchers should help farmers to find the optimal level of irrigation water use based on their own circumstances and provide better water-saving techniques and training programs rather than simply encouraging farmers to invest in irrigation facilities in the most extreme weather years; and iii) the income level of farm households should be increased so as to improve their resilience to natural disasters.

A Mathematical Calculation Model Using Biomarkers to Quantitatively Determine the Relative Source Proportion of Mixed Oils

It is difficult to identify the source（s） of mixed oils from multiple source rocks, and in particular the relative contribution of each source rock. Artificial mixing experiments using typical crude oils and ratios of different biomarkers show that the relative contribution changes are non-linear when two oils with different concentrations of biomarkers mix with each other. This may result in an incorrect conclusion if ratios of biomarkers and a simple binary linear equation are used to calculate the contribution proportion of each end-member to the mixed oil. The changes of biomarker ratios with the mixing proportion of end-member oils in the trinal mixing model are more complex than in the binary mixing model. When four or more oils mix, the contribution proportion of each end-member oil to the mixed oil cannot be calculated using biomarker ratios and a simple formula. Artificial mixing experiments on typical oils reveal that the absolute concentrations of biomarkers in the mixed oil cause a linear change with mixing proportion of each end-member. Mathematical inferences verify such linear changes. Some of the mathematical calculation methods using the absolute concentrations or ratios of biomarkers to quantitatively determine the proportion of each end-member in the mixed oils are deduced from the results of artificial experiments and by theoretical inference. Ratio of two biomarker compounds changes as a hyperbola with the mixing proportion in the binary mixing model, as a hyperboloid in the trinal mixing model, and as a hypersurface when mixing more than three end- members. The mixing proportion of each end-member can be quantitatively determined with these mathematical models, using the absolute concentrations and the ratios of biomarkers. The mathematical calculation model is more economical, convenient, accurate and reliable than conventional artificial mixing methods.