scholarly journals The Implications of HIV Treatment on the HIV-Malaria Coinfection Dynamics: A Modeling Perspective

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
F. Nyabadza ◽  
B. T. Bekele ◽  
M. A. Rúa ◽  
D. M. Malonza ◽  
N. Chiduku ◽  
...  

Most hosts harbor multiple pathogens at the same time in disease epidemiology. Multiple pathogens have the potential for interaction resulting in negative impacts on host fitness or alterations in pathogen transmission dynamics. In this paper we develop a mathematical model describing the dynamics of HIV-malaria coinfection. Additionally, we extended our model to examine the role treatment (of malaria and HIV) plays in altering populations’ dynamics. Our model consists of 13 interlinked equations which allow us to explore multiple aspects of HIV-malaria transmission and treatment. We perform qualitative analysis of the model that includes positivity and boundedness of solutions. Furthermore, we evaluate the reproductive numbers corresponding to the submodels and investigate the long term behavior of the submodels. We also consider the qualitative dynamics of the full model. Sensitivity analysis is done to determine the impact of some chosen parameters on the dynamics of malaria. Finally, numerical simulations illustrate the potential impact of the treatment scenarios and confirm our analytical results.

2021 ◽  
Vol 118 (4) ◽  
pp. e2021844118
Author(s):  
Pierre Lefebvre ◽  
Alkiviadis Gourgiotis ◽  
Arnaud Mangeret ◽  
Pierre Sabatier ◽  
Pierre Le Pape ◽  
...  

The long-term fate of uranium-contaminated sediments, especially downstream former mining areas, is a widespread environmental challenge. Essential for their management is the proper understanding of uranium (U) immobilization mechanisms in reducing environments. In particular, the long-term behavior of noncrystalline U(IV) species and their possible evolution to more stable phases in subsurface conditions is poorly documented, which limits our ability to predict U long-term geochemical reactivity. Here, we report direct evidence for the evolution of U speciation over 3,300 y in naturally highly U-enriched sediments (350–760 µg ⋅ g−1 U) from Lake Nègre (Mercantour Massif, Mediterranean Alps, France) by combining U isotopic data (δ238U and (234U/238U)) with U L3-edge X-ray absorption fine structure spectroscopy. Constant isotopic ratios over the entire sediment core indicate stable U sources and accumulation modes, allowing for determination of the impact of aging on U speciation. We demonstrate that, after sediment deposition, mononuclear U(IV) species associated with organic matter transformed into authigenic polymeric U(IV)–silica species that might have partially converted to a nanocrystalline coffinite (UIVSiO4·nH2O)-like phase. This diagenetic transformation occurred in less than 700 y and is consistent with the high silica availability of sediments in which diatoms are abundant. It also yields consistency with laboratory studies that proposed the formation of colloidal polynuclear U(IV)–silica species, as precursors for coffinite formation. However, the incomplete transformation observed here only slightly reduces the potential lability of U, which could have important implications to evaluate the long-term management of U-contaminated sediments and, by extension, of U-bearing wastes in silica-rich subsurface environments.


2019 ◽  
Vol 11 (14) ◽  
pp. 3775 ◽  
Author(s):  
Andreea Simona Saseanu ◽  
Rodica-Manuela Gogonea ◽  
Simona Ioana Ghita ◽  
Radu Şerban Zaharia

Currently, the problem of waste reduction is a permanent concern for all countries of the world, given the need to ensure the sustainability development. In this context, the research aims to highlight the impact of education and demographic factors by residence areas on the long-term behavior of the amount of waste generated in 29 European countries during 2013–2017. The study is based on statistical and econometric modeling aimed at identifying, testing and analyzing the existence of long-term correlation between the amount of waste per capita recorded in each country and four factors of influence considered significant for waste reduction: Pupils and students by education level and Classroom teachers and academic staff by education level, representing exogenous variables which quantify the educational outcomes, as well as The population by degree of urbanization (cities, rural areas), as demographic factors. As a result of an analysis based on correlation and regression method, a cointegration relationship between the analyzed variables was identified. Considering the amount of waste as an important component of the environmental pressure, the obtained results show the significant long-term effect that education and the demographic factor can have on its long-lasting behavior, as well as the ways through which these factors can act to strengthen sustainability.


2020 ◽  
Vol 25 ◽  
Author(s):  
N. Daniels ◽  
C. Cosma ◽  
A. Llewellyn ◽  
D. Banks ◽  
H. Morris ◽  
...  

Abstract Smoking was one of the biggest preventable killers of the 20th century, and it continues to cause the death of millions across the globe. The rapid growth of the e-cigarette market in the last 10 years and the claims that it is a safer form of smoking, and can help with smoking cessation, have led to questions being raised on their possible impact to society, the health of the population and the insurance industry. Recent media attention around the possible health implications of e-cigarette use has also ensured that this topic remains in the public eye. The e-cigarette working party was initiated by the Institute and Faculty of Actuaries’ Health and Care Research Sub-Committee in July 2016, with the primary objective of understanding the impact of e-cigarettes on life and health insurance. In this paper, we have looked at all areas of e-cigarette usage and how it relates to insurance in the UK market. In particular, we have covered the potential risks and benefits of switching to e-cigarettes, the results of studies that have been published, the potential impact on underwriting and claims processes and the potential impact on pricing (based on what modelling is possible with the data available). Research in this area is still in its infancy and data are not yet mature, which makes predicting the long-term impact of e-cigarette smoking extremely challenging, for example, there are no studies that directly measure the mortality or morbidity impact of long-term e-cigarette use and so we have had to consider studies that consider more immediate health impacts or look more simply at the constituents of the output of an e-cigarette and compare them to that of a cigarette. The data issue is further compounded by the findings of studies and the advice of national health authorities often being conflicting. For example, while National Health Service England has publicly stated that it supports the growth of e-cigarette usage as an aid to reduce traditional smoking behaviour, the US Food and Drug Administration has been much more vocal in highlighting the perceived dangers of this new form of smoking. Users’ behaviour also adds complexity, as dual use (using both e-cigarettes and cigarettes) is seen in a high percentage of users and relapse rates back to cigarette smoking are currently unknown. Having talked to a number of experts in the field, we have discovered that there is certainly not a common view on risk. We have heard from experts who have significant concerns but also to experts who do believe that e-cigarettes are far safer than tobacco. We have purposefully considered conflicting evidence and have consulted with various parties so we can present differing points of view, thereby ensuring a balanced, unbiased and fair picture of our findings is presented. The evidence we have reviewed does suggest that e-cigarettes are a safer alternative to traditional smoking, but not as safe as non-smoking. There are no large, peer-reviewed, long-term studies yet available to understand the true impact of a switch to e-cigarette use, so currently we are unable to say where on the risk spectrum between cigarette smoking and life-time non-smoking it lies. We do not yet understand if the benefits seen in the studies completed so far will reduce the risk in the long term or whether other health risks will come to light following more prolonged use and study. This, coupled with concerns with the high proportion of dual use of cigarettes and e-cigarettes, relapse rates and the recent growth in medical problems linked with e-cigarette use, means that we need to wait for experience to emerge fully before firm conclusions can be drawn. Although we have presented a view, it is vitally important that our industry continues to monitor developments in this area and fully considers what next steps and future actions may be required to ensure our position reflects the potential benefits and risks that e-cigarette use may bring. We feel that the time is right for a body such as the IFoA to analyse the feasibility of collecting the necessary data through the Continuous Mortality Investigation that would allow us to better analyse the experience that is emerging.


2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Sharon L. Weyers ◽  
Kurt A. Spokas

Despite the overwhelming importance of earthworm activity in the soil system, there are a limited number of studies that have examined the impact resulting from biochar addition to soil. Biochar is part of the black carbon continuum of chemo-thermal converted biomass. This review summarizes existing data pertaining to earthworms where biochar and other black carbon substances, including slash-and-burn charcoals and wood ash, have been applied. After analyzing existing studies on black carbon, we identified that these additions have a range from short-term negative impacts to long-term null effects on earthworm population density and total biomass. Documented cases of mortality were found with certain biochar-soil combinations; the cause is not fully understood, but hypothesized to be related to pH, whether the black carbon is premoistened, affects feeding behaviors, or other unknown factors. With wood ashes, negative impacts were overcome with addition of other carbon substrates. Given that field data is limited, soils amended with biochar did not appear to cause significant long-term impacts. However, this may indicate that the magnitude of short-term negative impacts on earthworm populations can be reduced with time.


2018 ◽  
Vol 63 (1) ◽  
pp. 41-47
Author(s):  
N. B. Rostova ◽  
N. A. Gudilina

Results of evaluation of the impact of drugs on indicators of clinical laboratory diagnostics as a criterion of safety of therapy are presented. Antiretroviral therapy for HIV infection was chosen as an example. Information from official sources (summary of product characteristics and medicinal product labels) on the potential impact of antiretroviral drugs registered in the Russian Federation on indicators of clinical laboratory diagnostics was analyzed and systematized. Individual INN and antiretroviral regimens recommended by WHO documents and protocols of follow-up and treatment of patients with HIV infection in the Russian Federation with the maximum and minimum potential impact on indicators of clinical laboratory diagnostics were revealed. The research results can be used to develop recommendations for the rational choice, prescription and use of medicines.


Author(s):  
Vincenzo Asero ◽  
Venera Tomaselli

Events create different types of impact on the local economy and host communities. They can trigger a variety of short- or long-term, positive or negative impacts. Literature distinguishes the term ‘impact' from ‘legacy.' While impacts affect the economy of the host place in the short-term, legacy remains longer than the event itself. Thus, if residents perceive benefits from the event, they will be supportive of hosting in the future. This chapter focuses on events as entrepreneurial opportunities of tourism and hospitality for a hosting place. It is based on the perceptions expressed by the different categories of local stakeholders involved in an international literary festival hosted in Italy. The study shows that evaluating and understanding the legacy effects for a place hosting an event, as perceived by the different local stakeholders involved, can provide managerial insights for planning over time events in the same place.


2016 ◽  
Vol 722 ◽  
pp. 151-156
Author(s):  
Ondřej Zobal ◽  
Pavel Padevět

The paper deals with the long-term development of strength of cement paste with fly ash. If the fly ash replaces the clinker in the cement or concrete mixture, the properties of the fresh and hardened material are affected. The slower increase in the strength of concrete is one of the biggest negative impacts. However, there are applications where it does not matter - e.g. massive concrete structure. It is important due to the ever increasing requirement from society for saving material and energy and durability of structures monitoring long-term behavior of such modified material. Three different mixtures were made for this experiment - cement paste without fly ash and cement paste with replacement of 40 and 50% of cement by fly ash. The evaluation of the measurement of compressive and tensile strength after 28, 90, 180 days and 5 years is presented in this paper.


2021 ◽  
Author(s):  
Mary Rose Angeles ◽  
Sithara Wanni Arachchige Dona ◽  
Dieu Nguyen ◽  
Long Le ◽  
Martin Hensher

Abstract Background Concerns have grown that post-acute sequelae of COVID-19 may affect significant numbers of survivors. However, the analyses used to guide policy-making for Australia’s national and state re-opening plans have not incorporated non-acute illness in their modelling. We therefore develop a model by which to estimate the potential acute and post-acute COVID-19 burden using disability-adjusted life years (DALYs) associated with the re-opening of Australian borders and the easing of other public health measures, with particular attention to longer term, post-acute consequences and the potential impact of permanent functional impairment following COVID-19. Methods A model was developed to estimate the burden of COVID-19 using DALYs. It was then applied to different scenarios drawn from the Doherty Institute’s modelling report, to estimate the likely DALY losses under the Australian national reopening plan. Uncertainty and sensitivity analysis were performed to examine the robustness of the results. Results Mortality was responsible for 72%-74% of the total base case COVID-19 burden. Long COVID and post-intensive care syndrome accounted for at least 19% and 3% of the total base case DALYs respectively. When included in the analysis, permanent impairment could contribute up to 51%-55% of total DALYs lost. Conclusions The impact of Long COVID and potential long-term post-COVID disabilities could contribute substantially to COVID-19 burden in Australia’s post-vaccination setting. As vaccination coverage increases, the share of COVID-19 burden driven by longer-term morbidity rises relative to mortality. As Australia re-opens, better estimates of COVID-19 burden can assist with decision-making on pandemic control measures and planning for the healthcare needs of COVID-19 survivors. Our estimates highlight the importance of valuing the morbidity of post-COVID-19 sequelae, above and beyond simple mortality and case statistics.


2018 ◽  
Vol 4 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Grace Alden Taylor

One-for-one companies, such as TOMS and Warby Parker, have become a common occurrence in the marketplace. These companies promise to donate a good or service for every product purchased. To date, millions of products have been donated worldwide. This paper seeks to analyze the positive and negative impacts of the one-for-one model on both the one-for-one company and the people receiving product donations. A specific focus of the paper is to determine whether the one-for-one model is helpful or harmful to companies and beneficiaries. To gather information, I contacted sixteen one-for-one companies and asked for reports, gathered preliminary research completed by news outlets such as Forbes and the New York Times, and analyzed academic research. The study finds that the one-for-one model can be both helpful and harmful, depending on the conditions in which the giving is done. For example, if there is an immediate need for a good that cannot be produced in the beneficiary country, then a donation would be beneficial. However, if a donation such as shoes ultimately takes away jobs and reduces the market in the beneficiary country, then it causes more harm and long-term damage than it prevents. As this model becomes more common, it is important that consumers know the impact of their purchases on the beneficiaries and the companies know the benefits and repercussions of their actions.


2018 ◽  
Vol 29 (2) ◽  
pp. 19-36
Author(s):  
Nawaf M. Alshabibi Nawaf M. Alshabibi

This paper assesses the impact of long-term work zones in arterial roads on commercial activities in Dammam Metropolitan area. The study focuses on two cases of long-term work zones in arterials in two major cities in Dammam Metropolitan Area. The first case is a work zone with full lanes closure on Prince Mohamed Bin Fahad Road at the south east entrance of Dammam city. The second case is a work zone with full lanes closure on King Abdul-Aziz Road at the northern entrance of Al-Khobar City. Data collection relies on field survey including questionnaires to affected business owners and managers. The questionnaire has been developed to assess the impact before and during road works period, in the work zone, on mobility and accessibility to commercial activities. Field survey includes 201 commercial activities at two work zone locations. Answers have been registered in Excel spreadsheet. Data analysis includes percentages of change, means, and standard deviation of dependent variables before and during the presence of the work zone. It was found that long-term work zones on arterials have multiple negative impacts on workers, sales, and customers. These impacts are related to lack of mobility, accessibility and reduction of parking availability during work period. Also, restaurants and travel agencies were the most effected activities by work zone presence, while banks were the least effected.


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