Dynamic analysis of a malaria reaction-diffusion model with periodic delays and vector bias

<abstract><p>One of the most important vector-borne disease in humans is malaria, caused by <italic>Plasmodium</italic> parasite. Seasonal temperature elements have a major effect on the life development of mosquitoes and the development of parasites. In this paper, we establish and analyze a reaction-diffusion model, which includes seasonality, vector-bias, temperature-dependent extrinsic incubation period (EIP) and maturation delay in mosquitoes. In order to get the model threshold dynamics, a threshold parameter, the basic reproduction number $ R_{0} $ is introduced, which is the spectral radius of the next generation operator. Quantitative analysis indicates that when $ R_{0} &lt; 1 $, there is a globally attractive disease-free $ \omega $-periodic solution; disease is uniformly persistent in humans and mosquitoes if $ R_{0} &gt; 1 $. Numerical simulations verify the results of the theoretical analysis and discuss the effects of diffusion and seasonality. We study the relationship between the parameters in the model and $ R_{0} $. More importantly, how to allocate medical resources to reduce the spread of disease is explored through numerical simulations. Last but not least, we discover that when studying malaria transmission, ignoring vector-bias or assuming that the maturity period is not affected by temperature, the risk of disease transmission will be underestimate.</p></abstract>

Impact and Variability of Meteorological Parameters on Rice Crop at Siddharthnagar, Uttar Pradesh, India

The present study explores the impacts and variability of meteorological parameter on the rice yields at Siddharthnagar of Uttar Pradesh, India. This study that the maximum and minimum temperatures during the period 2011 to 2020 show increasing trends. Whereas the duration of sunlight increased in June and July. Whereas the rainfall data shows decreasing trends for the period August-September. Furthermore, this study suggests that there was a decrease in rainfall trends during the paddy growing period. A negative correlation was observed with rainfall, particularly during the duff stage, indicating that wetting during the flowering to maturity period may be decisive. This study suggests taking into account the variability of annual or seasonal temperatures and precipitation within the region. The warming trend and irregular precipitation over time may have a significant impact on paddy farming. As a result, plans must be developed to manage the impact of the current variability of meteorological parameters on the paddy yields in this district of Uttar Pradesh by developing appropriate alternatives for increasing paddy crop production.

The Liquidity Spillover Effects Between the Stock Index Futures and Spot Under the Fractal Market Hypothesis

In recent years, the extreme risk events occurred frequently in the financial market have not only brought huge losses to investors and inflicted heavy losses on the market, but also posed a severe challenge for the traditional effective market hypothesis. These extreme risk events are often accompanied by sudden plummeting of liquidity. Different from the efficient market hypothesis(EMT), firstly, this paper studies the nonlinear fluctuation characteristics and causes of contracts with different maturity periods in China stock index futures market under the framework of fractal market theory and using the multifractal detrended fluctuation model Secondly, under the framework of the fractal market theory, the existence of the liquidity spillover effect between the stock index futures and spot is tested, the direction, intensity, and contribution of spillover between stock index futures and spot are analyzed. Finally, there is a robustness test. The study finds that both stock index futures and stock index spot in China have obvious nonlinear fractal fluctuation characteristics, and stock index futures have higher degree of multifractal, the characteristics are related to correlated multifractal and distributed multifractal; the longer the maturity period of the stock index futures contract, the lower the multifractal degree; there are significant asymmetric liquidity spillover effects between the stock index futures and spot; the multifractal degree has an important influence on the intensity and contribution of the liquidity spillover effect, and the multifractal degree is inversely proportional to the intensity of liquidity spillover and the contribution of spot to futures fluctuations.

Thermal and radiation environments for assessing crop-weather relationship of soybean in eastern Madhya Pradesh

A field experiment was conducted during with three sowing dates (23 June, 8 July and 23 July) with three varieties (JS 20-29, JS 20-34 and JS 97-52) kharif season of 2016 and 2017 at Jabalpur in eastern Madhya Pradesh for assessing crop weather relationship in soybean through thermal and radiation environments. The results revealed that early sown crop attained more accumulated heat units, and yield decreased with delay in sowing. The maximum and minimum temperatures during reproductive stage were positively correlated with seed yield while negatively associated with vegetative and pod development stages. Photosynthetic active radiation absorption (APAR) was maximum in June sowing in semi-determinate JS 97-52 variety at pod formation stage. Maximum leaf area index (LAI) exhibited in June sown for JS 97-52 variety during pod formation stage. Seed yield increase with increased in APAR and LAI during pod formation stage. Season length difference between normal and actual crop maturity period increased with the decrease in GDD thereby suggesting a decline in yield due to shortening of crop growing period.

INTRODUCTION TO AFRICA YAM BEAN (SPHENOSTYLIS STENOCARPA (HOCHST. EX A. RICH.) HARMS)

Food security and malnutrition are great concerns in developing and under-developed nations. Climate change, political unrest, and all sorts of crises within these nations and their neighboring nations have contributed greatly to the issue of food insecurity, malnutrition, and hunger. Many food plants that have the potential to combat the challenges of food insecurities and malnutrition in the face of climate change have been neglected, under-utilized and some of the crops are on their way to extinction. African yam bean (AYB) is one of the numerous crops with great potential in overcoming the problems associated with food and nutritional insecurities. AYB under-utilization, poor acceptance, and neglect by the farmers and consumers may be a result of poor awareness about its nutritional and health benefits, poor agronomy practices adopted by the farmers, and other production limiting factors such as low yield and long maturity period. Information that can guide the farmers and consumers for the commercial production and processing of AYB is not readily available. This review aims to summarize and made available information on AYB for the farmers and the consumers for it to be commercialized and for the researchers to see reasons and areas to make improvements on the crop.

INFLUENCE OF COST LEADERSHIP STRATEGY ON PERFORMANCE OF THE INSURANCE COMPANIES IN KENYA

Purpose: The study sought to determine the influence of cost leadership strategy on performance of the insurance companies in Kenya. Specifically, the study aimed at establishing the influence of price of premiums, maturity period, market segment and nature of products. Methodology: The study adopted the descriptive research design method to ascertain and describe the characteristics of the variables. A sample size of 55 insurance companies was reached, and a semi-structured questionnaire was used to collect primary data from the respondents. Data was analyzed using the SPSS software, from which appropriate findings were presented. Findings: The study findings showed that the cost leadership strategy was largely applied in the insurance companies in Kenya, and most of them have realized great performance. Nonetheless, the study found that most insurance companies’ distribution channels for products are moderately entrenched and hence firms may not have been perfectly efficient in reducing associated costs. Unique Contribution to Theory, Practice and Policy: The study recommends that insurance firms should devote more resources to execution of cost leadership programs, adoption of effective premium pricing, and enhanced use of proprietary technology in enhancing the products’ quality. The study as well recommends that insurance forms should come up with effective strategies that will help them to gain a large market segment in Kenya in order to enhance their performance, as this will effectively help them in overcoming competition in their industry.

Reproductive Cycle and Size at First Maturity in Females of Brown Crab Callinectes Bellicosus (Stimpson 1859) in the Southwestern Gulf of California, Mexico

The reproductive cycle of the crustacean family Portunidae on the coast of the Pacific is not well known. Therefore, the reproductive cycle and the size at first maturity of brown crab Callinectes bellicosus and its relationship with environmental factors in the El Colorado Lagoon, Ahome, Sinaloa has been determined. A total of 360 females were collected from March 2012 to March 2013. The gonads were fixed in 10% formalin, histological cuts were made by the paraffin inclusion method and the hematoxylin and eosin staining technique. The diameter of oocytes was determined by stage. The size at first maturity was estimated by a logistic model. Females showed gametogenic activity during the entire study period. The maturity period was from March to November 2012, with two spawning peaks, in September 2012 and March 2013. Maturity was inversely influenced by temperature (r = -0.4454, P < 0.05) and no influence by salinity was observed (P > 0.05). The diameter of the oocytes showed significant differences between the development stages of the gonad (P = 0.001). The size at first maturity was 11.57 cm of carapace width for females of C. bellicosus.

Integrative analysis of metabolome and transcriptome profiles provides insight into the fruit pericarp pigmentation disorder caused by ‘Candidatus Liberibacter asiaticus’ infection

Background Mandarin ‘Shatangju’ is susceptible to Huanglongbing (HLB) and the HLB-infected fruits are small, off-flavor, and stay-green at the maturity period. To understand the relationship between pericarp color and HLB pathogen and the effect mechanism of HLB on fruit pericarp coloration, quantitative analyses of HLB bacterial pathogens and carotenoids and also the integrative analysis of metabolome and transcriptome profiles were performed in the mandarin ‘Shatangju’ variety with four different color fruits, whole green fruits (WGF), top-yellow and base-green fruits (TYBGF), whole light-yellow fruits (WLYF), and whole dark-yellow fruits (WDYF) that were infected with HLB. Results the HLB bacterial population followed the order WGF > TYBGF > WLYF > WDYF. And there were significant differences between each group of samples. Regarding the accumulation of chlorophyll and carotenoid, the chlorophyll-a content in WGF was the highest and in WDYF was the lowest. The content of chlorophyll-b in WGF was significantly higher than that in other three pericarps. There were significant differences in the total content of carotenoid between each group. WGF and TYBGF pericarps were low in phytoene, γ-carotene, β-cryptoxanthin and apocarotenal, while other kinds of carotenoids were significantly higher than those in WDYF. And WLYF was only short of apocarotenal. We comprehensively compared the transcriptome and metabolite profiles of abnormal (WGF, TYBGF and WLYF) and normal (WDYF, control) pericarps. In total, 2,880, 2,782 and 1,053 differentially expressed genes (DEGs), including 121, 117 and 43 transcription factors were identified in the three comparisons, respectively. The qRT-PCR confirmed the expression levels of genes selected from transcriptome. Additionally, a total of 77 flavonoids and other phenylpropanoid-derived metabolites were identified in the three comparisons. Most (76.65 %) showed markedly lower abundances in the three comparisons. The phenylpropanoid biosynthesis pathway was the major enrichment pathway in the integrative analysis of metabolome and transcriptome profiles. Conclusions Synthesizing the above analytical results, this study indicated that different color pericarps were associated with the reduced levels of some carotenoids and phenylpropanoids derivatives products and the down-regulation of proteins in flavonoids, phenylpropanoids derivatives biosynthesis pathway and the photosynthesis-antenna proteins.

Prospects of raising baobab (Adansonia digitata L.) to fruiting in two years

Baobab is a very important plant with several uses, serving as food security crop and has the potential to raise income of farmers. However, the plant is undomesticated. We have the objective of domesticating the plant and promote its cultivation and utilization. Seeds were treated with sulphuric acid for early germination and grafted with matured scions suspected to be fruiting for several years. Twenty-two of the seedlings were transplanted on the field at Ho Technical University campus. Unfortunately, only four survived bushfire and destruction by stray animals. Surprisingly, one of the four surviving trees anthesis within twenty-eight months after seed treatment (twenty months after transplanting). This is the earliest ever reported anthesis of baobab. With better agronomic practices such as supplementary irrigation, insect pest control, manuring and protection from stray animals, baobab could start fruiting within two years of planting. This would alleviate fear of long maturity period and motivate farmers to go into baobab plantation. This would help diversify agriculture in many African countries, increase income and food security and contribute towards the attainment of the sustainable development goals of the United Nations.

Research of Balance of Forces Affecting on the Grain Between Cylindrical Rolls of Small-Size Feed Mincing Unit

The conducted research is devoted to the study of the balance of forces affecting on the grain between cylindrical rolls of the small-size feed mincing unit used in farming enterprises. It is established that substantiation of design and process parameters of the feed mincing units, plotting the analytical dependences and solution of process tasks are among the most important factors in manufacture of various versions of the unit. Using the obtained analytical solutions increase the efficiency of the works performed in this field. Recently, in the countries where the grain is harvested using the two-phase method, it is performed during the milk maturity period by pressing with special grinding machines immediately in the field, adding the conserving agent, preserving, packing into polyethylene bags, and then storing tight during winter. It is proven that the production costs for such nutritive grain feed reduce by 30% in contrast to the usual method. The grain stored in such a way is taken out of the grain bags and used directly for feeding the animals. The research work aimed at substantiation of design and process parameters of the small-size, low energy-intensive units for feed oakum production functioning on the basis of the grinding method in the conditions of farming enterprise is of great relevance. The work purpose is to study the balance of forces affecting on the grain between cylindrical rolls of the small-size feed mincing unit.