Modelling cassava production and pest management under biotic and abiotic constraints

Abstract Key message We summarise modelling studies of the most economically important cassava diseases and arthropods, highlighting research gaps where modelling can contribute to the better management of these in the areas of surveillance, control, and host-pest dynamics understanding the effects of climate change and future challenges in modelling. Abstract For over 30 years, experimental and theoretical studies have sought to better understand the epidemiology of cassava diseases and arthropods that affect production and lead to considerable yield loss, to detect and control them more effectively. In this review, we consider the contribution of modelling studies to that understanding. We summarise studies of the most economically important cassava pests, including cassava mosaic disease, cassava brown streak disease, the cassava mealybug, and the cassava green mite. We focus on conceptual models of system dynamics rather than statistical methods. Through our analysis we identified areas where modelling has contributed and areas where modelling can improve and further contribute. Firstly, we identify research challenges in the modelling developed for the surveillance, detection and control of cassava pests, and propose approaches to overcome these. We then look at the contributions that modelling has accomplished in the understanding of the interaction and dynamics of cassava and its’ pests, highlighting success stories and areas where improvement is needed. Thirdly, we look at the possibility that novel modelling applications can achieve to provide insights into the impacts and uncertainties of climate change. Finally, we identify research gaps, challenges, and opportunities where modelling can develop and contribute for the management of cassava pests, highlighting the recent advances in understanding molecular mechanisms of plant defence.

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ENVIRONMENTAL DEVELOPMENTS IN MALAYSIA: A REVIEW ON CHALLENGES AND OPPORTUNITIES AHEAD TO ECO-INNOVATE

Malaysian Journal of Sustainable Environment ◽

10.24191/myse.v5i2.5614 ◽

2018 ◽

Vol 5 (2) ◽

pp. 1

Author(s):

JS Keshminder

Keyword(s):

Climate Change ◽

Self Regulation ◽

Command And Control ◽

Environmental Policies ◽

Not Given ◽

The World ◽

Challenges And Opportunities ◽

Cradle To Cradle ◽

And Control ◽

Regulation Approach

Climate change is taking a toll on governments around the world as it is a challenge to determine the most effective environmental policies to promote eco-innovation. This paper investigates the environmental developments that have taken place in Malaysia to address the challenges and opportunities to promote eco-innovation. Past and present literature was qualitatively analyzed to prepare the environmental review for this study. The results suggest that Malaysia is implementing more superior environmental policies to promote eco-innovation. Command and control-based approach is slowly being replaced with guided self-regulation approach and cradle-to-cradle principle. The evidence suggests several shortcomings where the large industries are not given adequate focus under the environmental agenda and a holistic eco-innovation framework is yet to emerge.

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Heating Up International Trade Law: Challenges and Opportunities Posed by Efforts to Combat Climate Change

Carbon & Climate Law Review ◽

10.21552/cclr/2008/1/32 ◽

2008 ◽

Vol 2 (1) ◽

pp. 11 ◽

Cited By ~ 2

Author(s):

R. Tarasofsky

Keyword(s):

Climate Change ◽

International Trade ◽

Trade Law ◽

International Trade Law ◽

Challenges And Opportunities ◽

Combat Climate Change ◽

Heating Up

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The Protective Effects of Green Tea Catechins in the Management of Neurodegenerative Diseases: A Review

Current Drug Discovery Technologies ◽

10.2174/1570163815666180219115453 ◽

2019 ◽

Vol 16 (1) ◽

pp. 57-65 ◽

Cited By ~ 3

Author(s):

Tahereh Farkhondeh ◽

Hanieh Shaterzadeh Yazdi ◽

Saeed Samarghandian

Keyword(s):

Neurodegenerative Diseases ◽

Signaling Pathways ◽

Green Tea ◽

Molecular Mechanisms ◽

Main Role ◽

Related Factor ◽

Protective Effects ◽

Tea Catechins ◽

Green Tea Catechins ◽

And Control

Background: The therapeutic strategies to manage neurodegenerative diseases remain limited and it is necessary to discover new agents for their prevention and control. Oxidative stress and inflammation play a main role in the pathogenesis of neurodegenerative diseases. The aim of this study is to review the effects of green tea catechins against the Neurodegenerative Diseases. Methods: In this study, we extensively reviewed all articles on the terms of Green tea, catechins, CNS disorders, and different diseases in PubMed, Science Direct, Scopus, and Google Scholar databases between the years 1990 and 2017. Results: The present study found that catechins, the major flavonoids in green tea, are powerful antioxidants and radical scavengers which possess the potential roles in the management of neurodegenerative diseases. Catechins modulate the cellular and molecular mechanisms through the inflammation-related NF-&#954;B and the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways. Conclusion: The findings of the present review shows catechins could be effective against neurodegenerative diseases due to their antioxidation and anti-inflammation effects and the involved biochemical pathways including Nrf2 and NF-kB signaling pathways.<P>

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Effects of Vector Maturation Time on the Dynamics of Cassava Mosaic Disease

Bulletin of Mathematical Biology ◽

10.1007/s11538-021-00921-4 ◽

2021 ◽

Vol 83 (8) ◽

Author(s):

F. Al Basir ◽

Y. N. Kyrychko ◽

K. B. Blyuss ◽

S. Ray

Keyword(s):

Time Delay ◽

Plant Density ◽

Plant Viruses ◽

Mosaic Disease ◽

Plant Diseases ◽

Cassava Mosaic Disease ◽

Maturation Time ◽

Negative Effect ◽

Dynamical Regimes

AbstractMany plant diseases are caused by plant viruses that are often transmitted to plants by vectors. For instance, the cassava mosaic disease, which is spread by whiteflies, has a significant negative effect on plant growth and development. Since only mature whiteflies can contribute to the spread of the cassava mosaic virus, and the maturation time is non-negligible compared to whitefly lifetime, it is important to consider the effects this maturation time can have on the dynamics. In this paper, we propose a mathematical model for dynamics of cassava mosaic disease that includes immature and mature vectors and explicitly includes a time delay representing vector maturation time. A special feature of our plant epidemic model is that vector recruitment is negatively related to the delayed ratio between vector density and plant density. We identify conditions of biological feasibility and stability of different steady states in terms of system parameters and the time delay. Numerical stability analyses and simulations are performed to explore the role of various parameters, and to illustrate the behaviour of the model in different dynamical regimes. We show that the maturation delay may stabilise epidemiological dynamics that would otherwise be cyclic.

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Water Temperature and Hydrological Modelling in the Context of Environmental Flows and Future Climate Change: Case Study of the Wilmot River (Canada)

Water ◽

10.3390/w13152101 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2101

Author(s):

Christian Charron ◽

André St-Hilaire ◽

Taha B.M.J. Ouarda ◽

Michael R. van den Heuvel

Keyword(s):

Climate Change ◽

Water Temperature ◽

Environmental Flows ◽

Low Flow ◽

Future Climate Change ◽

Climate Change Scenarios ◽

Water Abstraction ◽

Surface Water Flow ◽

Modelling Studies ◽

Rcp 8.5

Simulation of surface water flow and temperature under a non-stationary, anthropogenically impacted climate is critical for water resource decision makers, especially in the context of environmental flow determination. Two climate change scenarios were employed to predict streamflow and temperature: RCP 8.5, the most pessimistic with regards to climate change, and RCP 4.5, a more optimistic scenario where greenhouse gas emissions peak in 2040. Two periods, 2018–2050 and 2051–2100, were also evaluated. In Canada, a number of modelling studies have shown that many regions will likely be faced with higher winter flow and lower summer flows. The CEQUEAU hydrological and water temperature model was calibrated and validated for the Wilmot River, Canada, using historic data for flow and temperature. Total annual precipitation in the region was found to remain stable under RCP 4.5 and increase over time under RCP 8.5. Median stream flow was expected to increase over present levels in the low flow months of August and September. However, increased climate variability led to higher numbers of periodic extreme low flow events and little change to the frequency of extreme high flow events. The effective increase in water temperature was four-fold greater in winter with an approximate mean difference of 4 °C, while the change was only 1 °C in summer. Overall implications for native coldwater fishes and water abstraction are not severe, except for the potential for more variability, and hence periodic extreme low flow/high temperature events.

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Analysis of Pneumonia Occurrence in Relation to Climate Change in Tanga, Tanzania

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094731 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4731

Author(s):

Samweli Faraja Miyayo ◽

Patrick Opiyo Owili ◽

Miriam Adoyo Muga ◽

Tang-Huang Lin

Keyword(s):

Climate Change ◽

Negative Binomial ◽

Health Management ◽

Severe Pneumonia ◽

Positive Association ◽

Negative Binomial Regression ◽

Health Management Information System ◽

Cold Temperatures ◽

Climate Indicators ◽

And Control

In 2018, 70% of global fatalities due to pneumonia occurred in about fifteen countries, with Tanzania being among the top eight countries contributing to these deaths. Environmental and individual factors contributing to these deaths may be multifaceted, but they have not yet been explored in Tanzania. Therefore, in this study, we explore the association between climate change and the occurrence of pneumonia in the Tanga Region, Tanzania. A time series study design was employed using meteorological and health data of the Tanga Region collected from January 2016 to December 2018 from the Tanzania Meteorological Authority and Health Management Information System, respectively. The generalized negative binomial regression technique was used to explore the associations between climate indicators (i.e., precipitation, humidity, and temperature) and the occurrence of pneumonia. There were trend differences in climate indicators and the occurrence of pneumonia between the Tanga and Handeni districts. We found a positive association between humidity and increased rates of non-severe pneumonia (incidence rate ratio (IRR) = 1.01; 95% CI: 1.01–1.02; p ≤ 0.05) and severe pneumonia (IRR = 1.02; 95% CI: 1.01–1.03; p ≤ 0.05). There was also a significant association between cold temperatures and the rate of severe pneumonia in Tanga (IRR = 1.21; 95% CI: 1.11–1.33; p ≤ 0.001). Other factors that were associated with pneumonia included age and district of residence. We found a positive relationship between humidity, temperature, and incidence of pneumonia in the Tanga Region. Policies focusing on prevention and control, as well as promotion strategies relating to climate change-related health effects should be developed and implemented.

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Development of a triple antibody sandwich enzyme-linked immunosorbent assay for cassava mosaic disease detection using a monoclonal antibody to Sri Lankan cassava mosaic virus

Virology Journal ◽

10.1186/s12985-021-01572-6 ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Saengsoon Charoenvilaisiri ◽

Channarong Seepiban ◽

Mallika Kumpoosiri ◽

Sombat Rukpratanporn ◽

Nuchnard Warin ◽

...

Keyword(s):

Mosaic Virus ◽

Immunosorbent Assay ◽

Mosaic Disease ◽

Cassava Mosaic Disease ◽

Enzyme Linked Immunosorbent Assay ◽

Sri Lankan ◽

Stem Cuttings ◽

Field Samples ◽

Cassava Stem ◽

Cassava Mosaic Virus

Abstract Background Cassava mosaic disease (CMD) is one of the most devastating viral diseases for cassava production in Africa and Asia. Accurate yet affordable diagnostics are one of the fundamental tools supporting successful CMD management, especially in developing countries. This study aimed to develop an antibody-based immunoassay for the detection of Sri Lankan cassava mosaic virus (SLCMV), the only cassava mosaic begomovirus currently causing CMD outbreaks in Southeast Asia (SEA). Methods Monoclonal antibodies (MAbs) against the recombinant coat protein of SLCMV were generated using hybridoma technology. MAbs were characterized and used to develop a triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) for SLCMV detection in cassava leaves and stems. Assay specificity, sensitivity and efficiency for SLCMV detection was investigated and compared to those of a commercial ELISA test kit and PCR, the gold standard. Results A TAS-ELISA for SLCMV detection was successfully developed using the newly established MAb 29B3 and an in-house polyclonal antibody (PAb) against begomoviruses, PAb PK. The assay was able to detect SLCMV in leaves, green bark from cassava stem tips, and young leaf sprouts from stem cuttings of SLCMV-infected cassava plants without cross-reactivity to those derived from healthy cassava controls. Sensitivity comparison using serial dilutions of SLCMV-infected cassava sap extracts revealed that the assay was 256-fold more sensitive than a commercial TAS-ELISA kit and 64-fold less sensitive than PCR using previously published SLCMV-specific primers. In terms of DNA content, our assay demonstrated a limit of detection of 2.21 to 4.08 × 106 virus copies as determined by quantitative real-time PCR (qPCR). When applied to field samples (n = 490), the TAS-ELISA showed high accuracy (99.6%), specificity (100%), and sensitivity (98.2%) relative to the results obtained by the reference PCR. SLCMV infecting chaya (Cnidoscolus aconitifolius) and coral plant (Jatropha multifida) was also reported for the first time in SEA. Conclusions Our findings suggest that the TAS-ELISA for SLCMV detection developed in this study can serve as an attractive tool for efficient, inexpensive and high-throughput detection of SLCMV and can be applied to CMD screening of cassava stem cuttings, large-scale surveillance, and screening for resistance.

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Over-the-counter sales of antibiotics for human use in India: The challenges and opportunities for regulation

Medical Law International ◽

10.1177/09685332211020786 ◽

2021 ◽

Vol 21 (2) ◽

pp. 147-173

Author(s):

Gerard Porter ◽

Anita Kotwani ◽

Lovleen Bhullar ◽

Jyoti Joshi

Keyword(s):

Stakeholder Participation ◽

Economic Incentives ◽

Social Scientists ◽

Over The Counter ◽

Middle Income ◽

Information Campaigns ◽

Challenges And Opportunities ◽

Regulatory Instruments ◽

Human Use ◽

And Control

This article assesses the regulatory framework relating to over-the-counter (OTC) sales of antibiotics for human use in India. The OTC sale of antibiotics is recognised as a pathway for the emergence of antimicrobial resistance (AMR); a serious public health challenge in need of urgent regulatory responses. Analytically, this article identifies opportunities within existing laws in India and highlights gaps that need to be filled by modifying existing laws or developing new ones. Conceptually, it suggests a need to reflect on the limits of traditional, top-down, ‘command-and control’ regulation and to think about alternative approaches. The article therefore advocates for an approach to regulation that incorporates two elements. First, it argues for a broader concept of regulation that encompasses binding as well as non-binding regulatory instruments and initiatives aimed at influencing stakeholder behaviour (including soft regulation, economic incentives, information campaigns and uses of technology). Second, it makes the case for enhanced stakeholder participation in regulatory design. The article will be relevant for health policy and drug regulators in India and other low- and middle-income countries, as well as legal scholars, social scientists and others interested in the regulation of OTC sales of antibiotics for AMR containment.

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Proanthocyanidins against Oxidative Stress: From Molecular Mechanisms to Clinical Applications

BioMed Research International ◽

10.1155/2018/8584136 ◽

2018 ◽

Vol 2018 ◽

pp. 1-11 ◽

Cited By ~ 12

Author(s):

Lingyu Yang ◽

Dehai Xian ◽

Xia Xiong ◽

Rui Lai ◽

Jing Song ◽

...

Keyword(s):

Oxidative Stress ◽

Signaling Pathways ◽

Molecular Mechanisms ◽

Metabolic Diseases ◽

Low Cost ◽

Natural Agents ◽

Molecular Damage ◽

And Control

Proanthocyanidins (PCs) are naturally occurring polyphenolic compounds abundant in many vegetables, plant skins (rind/bark), seeds, flowers, fruits, and nuts. Numerousin vitroandin vivostudies have demonstrated myriad effects potentially beneficial to human health, such as antioxidation, anti-inflammation, immunomodulation, DNA repair, and antitumor activity. Accumulation of prooxidants such as reactive oxygen species (ROS) exceeding cellular antioxidant capacity results in oxidative stress (OS), which can damage macromolecules (DNA, lipids, and proteins), organelles (membranes and mitochondria), and whole tissues. OS is implicated in the pathogenesis and exacerbation of many cardiovascular, neurodegenerative, dermatological, and metabolic diseases, both through direct molecular damage and secondary activation of stress-associated signaling pathways. PCs are promising natural agents to safely prevent acute damage and control chronic diseases at relatively low cost. In this review, we summarize the molecules and signaling pathways involved in OS and the corresponding therapeutic mechanisms of PCs.

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