Ecology of the maize stalk borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae)

1987 ◽  
Vol 77 (2) ◽  
pp. 255-269 ◽  
Author(s):  
J. B. J. Van Rensburg ◽  
M. C. Walters ◽  
J. H. Giliomee
Keyword(s):  
Plant Development ◽  
Busseola Fusca ◽  
Cost Effective ◽  
Control Measures ◽  
Effective Control ◽  
Planting Dates ◽  
Plant Parts ◽  
New Information ◽  
Repeated Sampling ◽  
Definite Pattern

AbstractNew information on the intraseasonal progression of larval infestations of Busseola fusca (Fuller) in South Africa was obtained through repeated sampling in maize plantings of different planting dates over various seasons. Due to the occurrence of distinct periods of moth flight, variation in planting date had a marked influence on levels of larval infestation. Also, plants were found to be most attractive as sites for oviposition between three and five weeks after emergence, resulting in a definite pattern in the time distribution of different larval instars in different plant parts. In the pre-tassel stage of plant development, most larvae occurred in localized groups within the whorls, reaching maximum numbers eight weeks after plant emergence. The emergence of the tassel forced some larvae to migrate to adjacent plants, resulting in an increase of internally damaged plants without an increase in larval numbers. It is shown that scouting for eggs over a limited period of plant development can lead to better timing of spray applications and thus to more cost-effective control measures.

Water safety plans for small systems: a model for applying HACCP concepts for cost-effective monitoring in developing countries

2003 ◽  
Vol 47 (3) ◽  
pp. 215-220 ◽  
Author(s):  
G. Howard
Keyword(s):  
Risk Factors ◽  
Water Quality ◽  
Cost Effective ◽  
Control Measures ◽  
Effective Control ◽  
Performance Limits ◽  
Water Safety ◽  
Small Systems ◽  
Water Safety Plans ◽  
Contamination Events

The development of water safety plans (WSPs) for small systems should be based on a thorough understanding of the relationships between risk factors and contamination events. This can be achieved through the use of well-designed assessments of water quality that provide better evidence to support the identification of control measures, performance limits, monitoring parameters and verification procedures. Training of community operators is critical to the success of the WSP and the understanding gained from the assessments provides a sound basis for addressing these needs. The WSP approach provides for more effective control of water quality and the use of targeted assessments is cost-effective in improving the design of WSPs.

scholarly journals Development of a Sanitation Safety Plan for improving the sanitation system in peri-urban areas of Iringa, Tanzania

2017 ◽  
Vol 7 (2) ◽  
pp. 340-348 ◽  
Author(s):  
M. Domini ◽  
G. Langergraber ◽  
L. Rondi ◽  
S. Sorlini ◽  
S. Maswaga
Keyword(s):  
Urban Areas ◽  
Cost Effective ◽  
Control Measures ◽  
Effective Control ◽  
Safety Plan ◽  
First Results ◽  
Assessment Matrix ◽  
Planning Methodology ◽  
The Given

The Sanitation Safety Planning methodology is implemented within a cooperation project in Iringa, Tanzania. The study presents the methodology and its adaptation and use for the given context, in order to assess risks and to support stakeholders in improving the current sanitation system and validate the design of an improved one. First results of the application of the methodology, obtained in one of the four peri-urban wards of Iringa, demonstrated its efficacy and utility in prioritising risks and identifying cost-effective control measures. Risks were assessed by the use of a semi-quantitative approach, and a simplified risk assessment matrix was developed for the case study. A sensitivity analysis was carried out in order to evaluate criteria for prioritising control measures to be selected for the development of an achievable improvement plan.

scholarly journals Estimating the basic reproduction number for the 2015 bubonic plague outbreak in Nyimba district of Eastern Zambia

2020 ◽  
Vol 14 (11) ◽  
pp. e0008811
Author(s):  
Joseph Sichone ◽  
Martin C. Simuunza ◽  
Bernard M. Hang’ombe ◽  
Mervis Kikonko
Keyword(s):  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Cost Effective ◽  
Control Measures ◽  
Effective Control ◽  
Infectious Period ◽  
Bubonic Plague ◽  
Infectious Individual ◽  
Susceptible Population ◽  
The Basic Reproduction Number

Background Plague is a re-emerging flea-borne infectious disease of global importance and in recent years, Zambia has periodically experienced increased incidence of outbreaks of this disease. However, there are currently no studies in the country that provide a quantitative assessment of the ability of the disease to spread during these outbreaks. This limits our understanding of the epidemiology of the disease especially for planning and implementing quantifiable and cost-effective control measures. To fill this gap, the basic reproduction number, R0, for bubonic plague was estimated in this study, using data from the 2015 Nyimba district outbreak, in the Eastern province of Zambia. R0 is the average number of secondary infections arising from a single infectious individual during their infectious period in an entirely susceptible population. Methodology/Principal findings Secondary epidemic data for the most recent 2015 Nyimba district bubonic plague outbreak in Zambia was analyzed. R0 was estimated as a function of the average epidemic doubling time based on the initial exponential growth rate of the outbreak and the average infectious period for bubonic plague. R0 was estimated to range between 1.5599 [95% CI: 1.382–1.7378] and 1.9332 [95% CI: 1.6366–2.2297], with average of 1.7465 [95% CI: 1.5093–1.9838]. Further, an SIR deterministic mathematical model was derived for this infection and this estimated R0 to be between 1.4 to 1.5, which was within the range estimated above. Conclusions/Significance This estimated R0 for bubonic plague is an indication that each bubonic plague case can typically give rise to almost two new cases during these outbreaks. This R0 estimate can now be used to quantitatively analyze and plan measurable interventions against future plague outbreaks in Zambia.

scholarly journals Transmission Dynamics of Corynebacterium spp. Within Two Danish Dairy Cattle Herds

2021 ◽  
Vol 8 ◽  
Author(s):  
Carsten Kirkeby ◽  
Tariq Halasa ◽  
Michael Farre ◽  
Galal Nazih Chehabi ◽  
Kaare Græsbøll
Keyword(s):  
Dairy Cattle ◽  
Transmission Rate ◽  
Cost Effective ◽  
Control Measures ◽  
Transmission Dynamics ◽  
Effective Control ◽  
Indirect Transmission ◽  
The Mean ◽  
Cattle Herds ◽  
Danish Dairy

Intramammary infections (IMI) can cause mastitis, a prevalent and costly infectious disease in dairy cattle worldwide. The IMI is caused by a range of bacteria, including Corynebacterium spp. Knowledge of the transmission dynamics of pathogens is generally sparse but essential to support decision-making; such as input to bioeconomic models. In this observational study, we explored the transmission dynamics of Corynebacterium spp. in two different Danish dairy cattle herds by testing monthly quarter-level milk samples of all lactating cows for 1 year. We estimated the prevalence for herd 1 and 2 to 24 and 11.7%, respectively, and the mean quarter-level incidence to be 8 and 6.5% per month, respectively. We compared a model for indirect transmission via the environment with a model with the direct contagious transmission and found that the latter model best explained the data. We estimated the daily mean quarter-level transmission rate to be 0.016 and 0.018 cases/quarter-day for herd 1 and 2, respectively. The mean recovery rate was 0.012 and 0.016 for herd 1 and 2, respectively. Consequently, the basic reproduction number for herd 1 and 2 was 1.27 and 1.10, respectively. This study highlights that Corynebacterium spp. can be prevalent within a herd and transmit directly between cows. Thus, future studies should investigate cost-effective control measures against Corynebacterium spp.

Enterprise Digital Twin

2020 ◽  
pp. 68-89
Author(s):  
Souvik Barat
Keyword(s):  
Control Measure ◽  
Dynamic Environment ◽  
Cost Effective ◽  
Control Measures ◽  
Effective Control ◽  
Digital Twin ◽  
The Core ◽  
Specific Objective ◽  
Effective Manner ◽  
Predictive Analyses

Enterprises constantly aim to maximise their objectives while operating in a competitive and dynamic environment. This necessitates an enterprise to be efficient, adaptive, and amenable for transformation. However, understanding a complex enterprise and identifying effective control measure, adaptation choice, or transformation option to realise specific objective is not a trivial task. The digital twin that imitates the real enterprise provides an environment to conduct the necessary interrogative and predictive analyses to evaluate various control measures, adaptation choices, and transformation options in a safe and cost-effective manner without compromising the analysis precision. This chapter reflects on the core concept of the digital twin, evaluates the state-of-the-art modelling and analysis technologies, and presents a pragmatic approach to develop high-fidelity digital twin for large complex enterprises.

scholarly journals Cost effective reproduction number based strategies for reducing deaths from COVID-19

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christopher Thron ◽  
Vianney Mbazumutima ◽  
Luis V. Tamayo ◽  
Léonard Todjihounde
Keyword(s):  
High Risk ◽  
Reproduction Number ◽  
Control Strategies ◽  
Cost Model ◽  
Cost Effective ◽  
Control Measures ◽  
Effective Control ◽  
Target Value ◽  
Heuristic Strategies ◽  
Implementation Costs

AbstractIn epidemiology, the effective reproduction number $R_{e}$ R e is used to characterize the growth rate of an epidemic outbreak. If $R_{e} >1$ R e > 1 , the epidemic worsens, and if $R_{e}< 1$ R e < 1 , then it subsides and eventually dies out. In this paper, we investigate properties of $R_{e}$ R e for a modified SEIR model of COVID-19 in the city of Houston, TX USA, in which the population is divided into low-risk and high-risk subpopulations. The response of $R_{e}$ R e to two types of control measures (testing and distancing) applied to the two different subpopulations is characterized. A nonlinear cost model is used for control measures, to include the effects of diminishing returns. Lowest-cost control combinations for reducing instantaneous $R_{e}$ R e to a given value are computed. We propose three types of heuristic strategies for mitigating COVID-19 that are targeted at reducing $R_{e}$ R e , and we exhibit the tradeoffs between strategy implementation costs and number of deaths. We also consider two variants of each type of strategy: basic strategies, which consider only the effects of controls on $R_{e}$ R e , without regard to subpopulation; and high-risk prioritizing strategies, which maximize control of the high-risk subpopulation. Results showed that of the three heuristic strategy types, the most cost-effective involved setting a target value for $R_{e}$ R e and applying sufficient controls to attain that target value. This heuristic led to strategies that begin with strict distancing of the entire population, later followed by increased testing. Strategies that maximize control on high-risk individuals were less cost-effective than basic strategies that emphasize reduction of the rate of spreading of the disease. The model shows that delaying the start of control measures past a certain point greatly worsens strategy outcomes. We conclude that the effective reproduction can be a valuable real-time indicator in determining cost-effective control strategies.

A model of cholera transmission with hyperinfectivity and its optimal vaccination control

2017 ◽  
Vol 10 (06) ◽  
pp. 1750084 ◽  
Author(s):  
Chairat Modnak
Keyword(s):  
Optimal Control Theory ◽  
Control Measure ◽  
Cost Effective ◽  
Control Measures ◽  
Equilibrium Analysis ◽  
Time Dependent ◽  
Effective Control ◽  
Health Control ◽  
Vaccination Strategies ◽  
Constant Control

The use of cholera vaccines has been increasingly recognized as an effective control measure in cholera endemic countries. Also, the disease transmissions are getting more complicated and thus comprehensive strategies to implement public health control measures are worthwhile to be investigated. In this paper, we aim to better understand the effects of HI states of vibrios from the environment and from human contacts that cause cholera outbreaks. We also present and analyze our cholera mathematical model with vaccine incorporated. Equilibrium analysis is conducted in the case with constant control for both epidemic and endemic dynamics. Optimal control theory is applied to seek cost-effective solutions of time-dependent vaccination strategies against cholera outbreaks. Our results show that using vaccination during cholera outbreaks at the very beginning of the onset can reduce the number of infections significantly.

scholarly journals Community Knowledge and Attitudes about the Transmission of Dengue Haemorrhagic Fever and Its Relationship to Prevention Behaviour in Palembang, South Sumatra, Indonesia

2021 ◽  
Vol 9 (E) ◽  
pp. 1534-1543
Author(s):  
Minarti Minarti ◽  
Chairil Anwar ◽  
Irfannuddin Irfannuddin ◽  
Chandra Irsan
Keyword(s):  
Vector Control ◽  
Control Measure ◽  
Public Awareness ◽  
Cost Effective ◽  
Hemorrhagic Fever ◽  
Control Measures ◽  
Good Knowledge ◽  
Effective Control ◽  
Control Practice ◽  
Prevention Behavior

BACKGROUND: PSN 3 M Plus is a long-running program in Indonesia for the prevention and control of dengue hemorrhagic fever (DHF). AIM: This study aimed to determine the knowledge, behavior, attitudes, and beliefs of the community toward PSN 3 M Plus in preventing and controlling the spread of DHF. METHODS: A cluster random sampling method was used to recruit 200 respondents in endemic areas and 100 respondents in sporadic locations of Indonesia from August 2020 to February 2021. The respondents were interviewed directly by interviewers and the relationships between demographics and characteristics with the practice of PSN 3M Plus prevention behavior on the incidence of DHF were analyzed. RESULTS: Most respondents had good knowledge regarding the cause of DHF. Although respondents recognized and understood the dangers of and how to control DHF, most did not follow PSN 3 M Plus and believed that fogging was the most effective control measure. There was a significant relationship between the characteristics of the respondents in terms of education, occupation, and attitude on vector control practice. CONCLUSION: Although community environmental modifications can be a cost-effective approach to reduce the incidence of DHF, there is a need to raise public awareness regarding preventive vector control measures as good knowledge does not guarantee good compliance with PSN 3M Plus recommendations.

Aspects of the injuriousness of the maize stalk borer, Busseola fusca (Fuller) (Lepidoptera: Noctuidae)

1988 ◽  
Vol 78 (1) ◽  
pp. 101-110 ◽  
Author(s):  
J. B. J. Van Rensburg ◽  
J. H. Giliomee ◽  
M. C. Walters
Keyword(s):  
South Africa ◽  
Busseola Fusca ◽  
Important Influence ◽  
Yield Losses ◽  
Stalk Borer ◽  
Plant Parts ◽  
Different Seasons ◽  
Repeated Sampling ◽  
Lepidoptera Noctuidae

AbstractThrough repeated sampling in maize planted on different dates over different seasons in South Africa, it was shown that damage by Busseola fusca (Fuller) to plant parts other than the whorl had an important influence on yield. Damage to plants in the period after tasselling was shown to be important. The number of larvae in the plant was a weak estimator of expected yield losses.

Two-stage chemical-biological treatment at Thessaloniki greater area WWTP - experiences and potentials

1995 ◽  
Vol 32 (9-10) ◽  
pp. 75-84 ◽  
Author(s):  
A. D. Andreadakis ◽  
G. H. Kristensen ◽  
A. Papadopoulos ◽  
C. Oikonomopoulos
Keyword(s):  
Biological Treatment ◽  
Treatment Plant ◽  
Cost Effective ◽  
Primary Treatment ◽  
Effective Control ◽  
Two Stage ◽  
Effluent Quality ◽  
Filamentous Microorganisms ◽  
Sludge Settling ◽  
The City

The wastewater from the city of Thessaloniki is discharged without treatment to the nearby inner part of the Thessaloniki Gulf. The existing, since 1989, treatment plant offers only primary treatment and did not operate since the expected effluent quality is not suitable for safe disposal to the available recipients. Upgrading of the plant for advanced biological treatment, including seasonal nitrogen removal, is due from 1995. In the mean time, after minor modifications completed in February 1992, the existing plant was put into operation as a two-stage chemical-biological treatment plant for 40 000 m3 d−1, which corresponds to about 35% of the total sewage flow. The operational results obtained during the two years operation period are presented and evaluated. All sewage and sludge treatment units of the plant perform better than expected, with the exception of the poor sludge settling characteristics, due to severe and persistent bulking caused by excessive growth of filamentous microorganisms, particularly M. Parvicella. Effective control of the bulking problem could lead to more cost-effective operation and increased influent flows.

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