scholarly journals Exploring the Impact of Climate Variability on Malaria Transmission Using a Dynamic Mosquito-Human Malaria Model

2018 ◽  
Vol 10 (1) ◽  
pp. 88-100 ◽  
Author(s):  
Gbenga J. Abiodun ◽  
Peter J. Witbooi ◽  
Kazeem O. Okosun ◽  
Rajendra Maharaj
Keyword(s):  
Climate Variability ◽  
Malaria Transmission ◽  
Malaria Incidence ◽  
Principal Component ◽  
Wavelet Coherence ◽  
Human Malaria ◽  
Kwazulu Natal ◽  
The Impact ◽  
Wavelet Coherence Analysis ◽  
Malaria Model

Introduction: The reasons for malaria resurgence mostly in Africa are yet to be well understood. Although the causes are often linked to regional climate change, it is important to understand the impact of climate variability on the dynamics of the disease. However, this is almost impossible without adequate long-term malaria data over the study areas. Methods: In this study, we develop a climate-based mosquito-human malaria model to study malaria dynamics in the human population over KwaZulu-Natal, one of the epidemic provinces in South Africa, from 1970-2005. We compare the model output with available observed monthly malaria cases over the province from September 1999 to December 2003. We further use the model outputs to explore the relationship between the climate variables (rainfall and temperature) and malaria incidence over the province using principal component analysis, wavelet power spectrum and wavelet coherence analysis. The model produces a reasonable fit with the observed data and in particular, it captures all the spikes in malaria prevalence. Results: Our results highlight the importance of climate factors on malaria transmission and show the seasonality of malaria epidemics over the province. Results from the principal component analyses further suggest that, there are two principal factors associated with climates variables and the model outputs. One of the factors indicate high loadings on Susceptible, Exposed and Infected human, while the other is more correlated with Susceptible and Recovered humans. However, both factors reveal the inverse correlation between Susceptible-Infected and Susceptible-Recovered humans respectively. Through the spectrum analysis, we notice a strong annual cycle of malaria incidence over the province and ascertain a dominant of one year periodicity. Consequently, our findings indicate that an average of 0 to 120-day lag is generally noted over the study period, but the 120-day lag is more associated with temperature than rainfall. This is consistence with other results obtained from our analyses that malaria transmission is more tightly coupled with temperature than with rainfall in KwaZulu-Natal province.

scholarly journals Exploring the Influence of Daily Climate Variables on Malaria Transmission and Abundance of Anopheles arabiensis over Nkomazi Local Municipality, Mpumalanga Province, South Africa

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Gbenga J. Abiodun ◽  
Kevin Y. Njabo ◽  
Peter J. Witbooi ◽  
Abiodun M. Adeola ◽  
Trevon L. Fuller ◽  
...  
Keyword(s):  
South Africa ◽  
Malaria Transmission ◽  
Anopheles Arabiensis ◽  
Climatic Factors ◽  
Time Lag ◽  
Wavelet Coherence ◽  
Study Region ◽  
Mosquito Abundance ◽  
The Impact ◽  
Wavelet Coherence Analysis

The recent resurgence of malaria incidence across epidemic regions in South Africa has been linked to climatic and environmental factors. An in-depth investigation of the impact of climate variability and mosquito abundance on malaria parasite incidence may therefore offer useful insight towards the control of this life-threatening disease. In this study, we investigate the influence of climatic factors on malaria transmission over Nkomazi Municipality. The variability and interconnectedness between the variables were analyzed using wavelet coherence analysis. Time-series analyses revealed that malaria cases significantly declined after the outbreak in early 2000, but with a slight increase from 2015. Furthermore, the wavelet coherence and time-lagged correlation analyses identified rainfall and abundance of Anopheles arabiensis as the major variables responsible for malaria transmission over the study region. The analysis further highlights a high malaria intensity with the variables from 1998–2002, 2004–2006, and 2010–2013 and a noticeable periodicity value of 256–512 days. Also, malaria transmission shows a time lag between one month and three months with respect to mosquito abundance and the different climatic variables. The findings from this study offer a better understanding of the importance of climatic factors on the transmission of malaria. The study further highlights the significant roles of An. arabiensis on malaria occurrence over Nkomazi. Implementing the mosquito model to predict mosquito abundance could provide more insight into malaria elimination or control in Africa.

Role of forest fires in Holocene stand-scale dynamics in the unmanaged taiga forest of northwestern Russia

The Holocene ◽  
2014 ◽  
Vol 24 (11) ◽  
pp. 1503-1514 ◽  
Author(s):  
Niina Kuosmanen ◽  
Keyan Fang ◽  
Richard HW Bradshaw ◽  
Jennifer L Clear ◽  
Heikki Seppä
Keyword(s):  
Forest Fires ◽  
Siberian Larch ◽  
Wavelet Coherence ◽  
Individual Tree ◽  
Study Region ◽  
Taiga Forest ◽  
The Impact ◽  
Wavelet Coherence Analysis ◽  
Northwestern Russia

Fossil pollen, conifer stomata, and charcoal records for the last 10,000 years were studied from three small hollow sites (Larix Hollow, Mosquito Hollow, and Olga Hollow) located at the modern western range limit of Siberian larch ( Larix sibirica) in northwestern Russia to investigate the role of forest fires in stand-scale dynamics of taiga vegetation. Wavelet coherence analysis was utilized to reveal the significance of fire on the vegetation composition at different timescales by assessing the phase and strength of the relationship between forest fires and most common boreal tree taxa in a time–frequency window. Pollen and stomata data show that all of the modern-day common tree taxa, including Norway spruce ( Picea abies) and Siberian larch, have been present in the study region since the early Holocene. The absence of charcoal layers at Mosquito Hollow suggests that this site has acted as a fire-free refugium with continuous dominance of spruce throughout the Holocene. Meanwhile, the Larix Hollow record indicates frequent local fire events and as a consequence, a more variable tree species composition. The wavelet coherence results show that the impact of forest fires on vegetation varies from short-term (<200-year periods) changes in individual tree taxa to long-term (400–800 years) changes in forest composition, such as the expansion of spruce population after local high-intensity fires around 7500–7000 cal. yr BP and the increase in abundance of birch and alder during periods of high fire frequency. Our results suggest that Holocene fire histories can be markedly different within a small geographical area, demonstrating the importance of site-specific factors in the local fire regime in the unmanaged taiga forest.

scholarly journals IMPACT OF TRADE OPENNESS ON ENVIRONMENT IN CHINA

2020 ◽  
Vol 21 (4) ◽  
pp. 1185-1202 ◽  
Author(s):  
Wen Jun ◽  
Hamid Mahmood ◽  
Muhammad Zakaria
Keyword(s):  
Carbon Emission ◽  
Trade Openness ◽  
Wavelet Coherence ◽  
Coherence Analysis ◽  
Pollution Haven Hypothesis ◽  
Causality Test ◽  
Pollution Haven ◽  
Analysis Phase ◽  
The Impact ◽  
Wavelet Coherence Analysis

The study investigates the impact of trade openness on pollution in China by applying wavelet-coherence analysis, phase-difference technique and Breitung and Candelon (2006) causality test. The estimated results provide some dynamic association between trade openness and pollutant variables. The results indicate that trade openness has increased pollution in China especially after 2001 when China became member of WTO. It suggests that “pollution haven hypothesis” exists in China. These results imply that trade openness has increased exports which has increased domestic production by increasing the scale of industries, which in turn has increased pollution in the country. The findings of spectral domain causality test show that trade openness causes carbon emission both in short, medium and long runs. It indicates that trade openness forecast carbon emissions in China. The results suggest that China should take suitable measures while following trade openness policy to avoid pollution.

scholarly journals Spatio-Temporal Dynamic of Malaria Incidence: A Comparison of Two Ecological Zones in Mali

2020 ◽  
Vol 17 (13) ◽  
pp. 4698 ◽  
Author(s):  
François Freddy Ateba ◽  
Issaka Sagara ◽  
Nafomon Sogoba ◽  
Mahamoudou Touré ◽  
Drissa Konaté ◽  
...  
Keyword(s):  
Malaria Transmission ◽  
Malaria Incidence ◽  
Additive Model ◽  
Principal Component ◽  
Environmental Data ◽  
Ecological Zones ◽  
Time Period ◽  
Passive Case Detection ◽  
Spatio Temporal ◽  
The Relationship

Malaria transmission largely depends on environmental, climatic, and hydrological conditions. In Mali, malaria epidemiological patterns are nested within three ecological zones. This study aimed at assessing the relationship between those conditions and the incidence of malaria in Dangassa and Koila, Mali. Malaria data was collected through passive case detection at community health facilities of each study site from June 2015 to January 2017. Climate and environmental data were obtained over the same time period from the Goddard Earth Sciences (Giovanni) platform and hydrological data from Mali hydraulic services. A generalized additive model was used to determine the lagged time between each principal component analysis derived component and the incidence of malaria cases, and also used to analyze the relationship between malaria and the lagged components in a multivariate approach. Malaria transmission patterns were bimodal at both sites, but peak and lull periods were longer lasting for Koila study site. Temperatures were associated with malaria incidence in both sites. In Dangassa, the wind speed (p = 0.005) and river heights (p = 0.010) contributed to increasing malaria incidence, in contrast to Koila, where it was humidity (p < 0.001) and vegetation (p = 0.004). The relationships between environmental factors and malaria incidence differed between the two settings, implying different malaria dynamics and adjustments in the conception and plan of interventions.

Oceanic Influence on Seasonal Malaria Incidence in West Africa.

2021 ◽  
Keyword(s):  
West Africa ◽  
Malaria Incidence ◽  
Early Warning Systems ◽  
Sst Variability ◽  
Air Temperatures ◽  
Key Factor ◽  
The Impact ◽  
Malaria Model ◽  
Sst Anomalies

Abstract Climate variability is a key factor in driving malaria outbreaks. As shown in previous studies, climate-driven malaria modeling provides a better understanding of malaria transmission dynamics, generating malaria-related parameters validated as a reliable benchmark to assess the impact of climate on malaria. In this framework, the present study uses climate observations and reanalysis products to evaluate the predictability of malaria incidence in West Africa. Sea surface temperatures (SSTs) are shown as a skillful predictor of malaria incidence, which is derived from climate-driven simulations with the Liverpool Malaria Model (LMM). Using the S4CAST tool, we find robust modes of anomalous SST variability associated with skillful predictability of malaria incidence Accordingly, significant SST anomalies in the tropical Pacific and Atlantic Ocean basins are related to a significant response of malaria incidence over West Africa. For the Mediterranean Sea, warm (cold) SST anomalies are responsible for increased (decreased) surface air temperatures and precipitation over West Africa, resulting in higher (lower) malaria incidence. Our results put forward the key role of SST variability as a source of predictability of malaria incidence, being of paramount interest to decision-makers who plan public health measures against malaria in West Africa. Accordingly, SST anomalies could be used operationally to forecast malaria risk over West Africa for early warning systems.

scholarly journals Effect of Structural Funds on Housing Market Sustainability Development—Correlation, Regression and Wavelet Coherence Analysis

Risks ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 182
Author(s):  
Łukasz Mach ◽  
Karina Bedrunka ◽  
Anna Kuczuk ◽  
Marzena Szewczuk-Stępień
Keyword(s):  
Positive Impact ◽  
Research Process ◽  
Global Scale ◽  
Real Estate Market ◽  
Wavelet Coherence ◽  
Time Variability ◽  
Coherence Analysis ◽  
Structural Funds ◽  
The Impact ◽  
Wavelet Coherence Analysis

Effective acquisition of funds, including European Union (EU) funds, designated for example, creating economic and social processes, may have a real impact on the elimination of the negative outcomes of the current position of the EU on the global scale. The aim of the research is to indicate the impact of spending funds from the Regional Operational Program of the Opolskie Voivodeship 2014–2020 (ROP OV) on a key macroeconomic area of the economy, i.e., the housing development sector in the region. The practical aim is to formulate recommendations and solutions that can offer guidelines for more effective spending of EU funds and their effect on the macroeconomic dimensions of the economy. The article proposes an innovative approach to linking EU payments in the region with the real estate market. The results of the research and the analyses made on this basis showed a positive impact of the payments made from the ROP OV on selected macroeconomic indicators, i.e., the number of permits issued for the construction of new apartments and the number of currently implemented housing investments. The obtained results should be used in the decision-making process at the level of regional and national authorities responsible for the payment of EU funds. In this article, prior to the research process, a literature review was made. It covered various aspects of the evolution and development of research in the area of regional development. The research process was based on innovative methods of time variability analysis, correlation between the investigated determinants and coherence analysis for the studied dimensions. Data on payments from the ROP OV concern the years 2015–2020.

scholarly journals ANALYSIS OF CLIMATE VARIABILITY AND ITS INFLUENCES ON SEASONAL RAINFALL PATTERNS ON THE BATEKE PLATEAUS IN THE REPUBLIC OF CONGO-BRAZZAVILLE

2021 ◽  
Vol 9 (01) ◽  
pp. 327-337
Author(s):  
Harmel Obami-Ondon ◽  
◽  
Medard Ngouala Mabonzo ◽  
Ngoma Mvoundou Christian ◽  
Bernard Mabiala ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Climate Variability ◽  
Principal Component ◽  
Climatic Conditions ◽  
Seasonal Rainfall ◽  
Republic Of Congo ◽  
Rainfall Patterns ◽  
The Republic ◽  
Congo Brazzaville ◽  
The Impact

Climate variability, in Africa in general and in the Republic of Congo-Brazzaville in particular, has been widely documented over the past 20 years. However, variables related to rainfall, such as the nine-month rainy seasons, have been very little studied in the Bateke Plateaux zone, which play a major role in regional hydrology. The objective of this study is to investigate the influence of climatic events on seasonal rainfall patterns on the Plateaux Bateke. On the one hand, it involves monitoring the evolution of climatic parameters through the analysis of temperature, relative humidity and rainfall variation. On the other hand, it was a question of comparing the monthly rainfall normals over the period 1987-2016 in order to determine the behaviour of seasonal rainfall patterns in the context of climate variability. The principal component analysis, based on nine (09) variables, highlighted the impact of climate variability on seasonal rainfall patterns. The first principal component (F1) is associated with the factors defining the climatic conditions of the Plateau Bateke. The second main component (F2) does not express clear correlations. Generally speaking, the temperature and relative humidity of the air are factors in the temporal variability of seasonal rainfall regimes on the Plateaux Bateke.

Comparing the impacts of climate modes of variability on coastal aquifers of Portugal and California

2020 ◽  
Author(s):  
Katherine Malmgren ◽  
Maria da Conceição Neves ◽  
Tina Gorge
Keyword(s):  
Climate Variability ◽  
Coastal Aquifers ◽  
Principal Component ◽  
Mode Interaction ◽  
Interaction Patterns ◽  
Climate Modes ◽  
Groundwater Levels ◽  
Groundwater Availability ◽  
Aquifer Systems ◽  
The Impact

&lt;p&gt;Understanding the impact of climate variability on aquifer systems is important to improve future projections of groundwater availability, particularly in the context of increasing water scarcity. Coastal aquifers in Mediterranean regions are particularly sensitive to inter-annual and seasonal water storage fluctuations linked to climate forcing and climate-induced pumping. This comparative study examines the implications of climate variability modes on groundwater levels in coastal aquifers of California and Portugal. Piezometric levels in selected aquifers in Portugal (Leirosa-Monte Real and Campina de Faro) and California (Coastal Basins aquifers), spanning a period from 1988 to 2018, are analyzed using wavelet transform methods and principal component analysis. The methods expose not only the impact of the individual climate modes (AMO, PDO, ENSO, PNA in California and NAO, EA and SCAND in Portugal) but also the existence of complex transitive couplings among modes. Together, the climate modes are responsible for most (80%) of the inter-annual variability in groundwater storage in both Portugal and California coastal aquifers. However, our most important result is the recognition that transitive couplings greatly affect the hydrological responses both in Portugal and California. Coupled phases are linked to extreme piezometric levels and are associated with shifts in mode-interaction patterns. The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 &amp;#8211; IDL.&lt;/p&gt;

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