scholarly journals An Equilibrium Model of the African HIV/AIDS Epidemic

Econometrica ◽  
2019 ◽  
Vol 87 (4) ◽  
pp. 1081-1113 ◽  
Author(s):  
Jeremy Greenwood ◽  
Philipp Kircher ◽  
Cezar Santos ◽  
Michèle Tertilt
Keyword(s):  
Field Experiments ◽  
Epidemiological Studies ◽  
Behavioral Changes ◽  
Sexual Practices ◽  
Small Scale ◽  
Equilibrium Search ◽  
Inherent Risk ◽  
Aids Epidemic ◽  
Policy Interventions ◽  
Equilibrium Search Model

Twelve percent of the Malawian population is HIV infected. Eighteen percent of sexual encounters are casual. A condom is used a third of the time. To analyze the Malawian epidemic, a choice‐theoretic general equilibrium search model is constructed. In the developed framework, people select between different sexual practices while knowing the inherent risk. The calibrated model is used to study several policy interventions, namely, ART, circumcision, better condoms, and the treatment of other STDs. The efficacy of public policy depends upon the induced behavioral changes and equilibrium effects. The framework complements the insights from epidemiological studies and small‐scale field experiments.

scholarly journals The Role of Marriage in Fighting HIV: A Quantitative Illustration for Malawi

2017 ◽  
Vol 107 (5) ◽  
pp. 158-162 ◽  
Author(s):  
Jeremy Greenwood ◽  
Philipp Kircher ◽  
Cezar Santos ◽  
Michèle Tertilt
Keyword(s):  
General Equilibrium ◽  
Field Experiments ◽  
Epidemiological Studies ◽  
Equilibrium Analysis ◽  
Equilibrium Search ◽  
Single Person ◽  
Equilibrium Search Model ◽  
Hiv Aids

How might policies that promote marriage and/or dissuade divorce help in the fight against HIV/AIDS? This question is addressed employing a choice-theoretic general equilibrium search model, using Malawi as a case study. In the framework developed, individuals can choose between married and single life. A single person can select among abstinence and sex with or without a condom. The results suggest that marriage-friendly policies can help to abate HIV/AIDS. The policy predictions that obtain from general equilibrium analysis are compared with those that arise from simulated synthetic field experiments and epidemiological studies.

scholarly journals Applications of Chemically Modified Clay Minerals and Clays to Water Purification and Slow Release Formulations of Herbicides

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 9
Author(s):  
Tomas Undabeytia ◽  
Uri Shuali ◽  
Shlomo Nir ◽  
Baruch Rubin
Keyword(s):  
Clay Minerals ◽  
Field Experiments ◽  
Slow Release ◽  
Freeze Fracture ◽  
Nano Particles ◽  
Organic Cations ◽  
Small Scale ◽  
High Exposure ◽  
Model Calculations ◽  
Slow Release Formulations

This review deals with modification of montmorillonite and other clay-minerals and clays by interacting them with organic cations, for producing slow release formulations of herbicides, and efficient removal of pollutants from water by filtration. Elaboration is on incorporating initially the organic cations in micelles and liposomes, then producing complexes denoted micelle- or liposome-clay nano-particles. The material characteristics (XRD, Freeze-fracture electron microscopy, adsorption) of the micelle– or liposome–clay complexes are different from those of a complex of the same composition (organo-clay), which is formed by interaction of monomers of the surfactant with the clay-mineral, or clay. The resulting complexes have a large surface area per weight; they include large hydrophobic parts and (in many cases) have excess of a positive charge. The organo-clays formed by preadsorbing organic cations with long alkyl chains were also addressed for adsorption and slow release of herbicides. Another examined approach includes “adsorptive” clays modified by small quaternary cations, in which the adsorbed organic cation may open the clay layers, and consequently yield a high exposure of the siloxane surface for adsorption of organic compounds. Small scale and field experiments demonstrated that slow release formulations of herbicides prepared by the new complexes enabled reduced contamination of ground water due to leaching, and exhibited enhanced herbicidal activity. Pollutants removed efficiently from water by the new complexes include (i) hydrophobic and anionic organic molecules, such as herbicides, dissolved organic matter; pharmaceuticals, such as antibiotics and non-steroidal drugs; (ii) inorganic anions, e.g., perchlorate and (iii) microorganisms, such as bacteria, including cyanobacteria (and their toxins). Model calculations of adsorption and kinetics of filtration, and estimation of capacities accompany the survey of results and their discussion.

A dynamic aggregative model of the AIDS epidemic with possible policy interventions

1994 ◽  
Vol 16 (5) ◽  
pp. 473-496 ◽  
Author(s):  
John T. Cuddington ◽  
John D. Hancock ◽  
Carol Ann Rogers
Keyword(s):  
Aids Epidemic ◽  
Policy Interventions

scholarly journals The Zarit Burden Interview in Portugal: Validity and Recommendations in Dementia and Palliative Care

2014 ◽  
Vol 27 (2) ◽  
pp. 163 ◽  
Author(s):  
Manuel Gonçalves-Pereira ◽  
Steven H. Zarit
Keyword(s):  
Palliative Care ◽  
Social Impact ◽  
Epidemiological Studies ◽  
Public Health Issue ◽  
Small Scale ◽  
Validity And Reliability ◽  
Services Research ◽  
Zarit Burden Interview ◽  
Exploratory Factor Analyses ◽  
The Impact

<p>The impact of dementia on informal or family caregivers became a public health issue. One well-established tool for the assessment of emotional, physical and social impact on caregivers is the Zarit Burden Interview. Worldwide, it is widely used in epidemiological studies, drug or psychosocial clinical trials, and health services research. The original focus on burden among dementia caregivers has spread to other clinical contexts, mostly in old age and palliative care. Given these diverse applications, issues around the validity and reliability of national translations are crucial to assure that all evidence gathered is indeed of high quality. Moreover, caution is needed on the use of cut-offs for categorizing levels of caregiver strain or of subscales derived from recurrent exploratory factor analyses in small-scale local studies. As with other translations of measures in the health field, researchers and clinicians in Portugal must be aware of how to address bias in using the Zarit Burden Interview and interpreting findings.</p>

scholarly journals A study on knowledge attitude and practices regarding HIV/AIDS among general population in a community of Kottarakkara, Kerala

2021 ◽  
Vol 8 (2) ◽  
pp. 613
Author(s):  
Nimmy N. John ◽  
Athira Krishnan Krishnan ◽  
H. Doddayya
Keyword(s):  
Sexual Intercourse ◽  
Sexual Practices ◽  
High Morbidity ◽  
Hiv Patients ◽  
Knowledge And Attitudes ◽  
Aids Epidemic ◽  
High Knowledge ◽  
History Of ◽  
General Populations ◽  
Hiv Aids

Background: HIV/AIDS epidemic has emerged as one of the most serious and enormous health problems associated with high morbidity and mortality rate. A prospective questionnaire based observational study was carried out in Kottathala community of Mylom Gramapanchayat, Kottarakkara to analyse the peoples knowledge on HIV/AIDS, as well as attitudes towards HIV patients and actual sex practices for the control or prevention of HIV.Methods: A total of 150 participants were interviewed by using a predesigned questionnaire and responses were reviewed and analysed by using descriptive statistics namely total numbers and percentage.Results: Out of 150 participants females were more (84%) and most of them were under the age group of 18-30 years. Majority of the participants had higher degree of education (51.33%) as they are still youth. The overall participants had a higher degree of knowledge regarding HIV and most of them had a positive attitude towards the HIV patients. Around 84% of participants had history of sexual intercourse but majority of them (46%) never used condoms during sexual intercourse in which, 11.33% only using condom regularly. Most of them were following unsafe sexual practices.Conclusions: This study concludes that the surveyed general populations had high knowledge and attitudes regarding HIV/AIDS and had risky sexual practices. 

Progress towards small-scale field trials of coastal enhanced weathering of olivine

2021 ◽  
Author(s):  
Stephen Romaniello ◽  
Shanee Stopnitzky ◽  
Tom Green ◽  
Francesc Montserrat ◽  
Eric Matzner ◽  
...  
Keyword(s):  
Real World ◽  
Field Experiments ◽  
Ecological Impact ◽  
Field Trials ◽  
Research Strategy ◽  
Unintended Consequences ◽  
Ecological Impacts ◽  
Small Scale ◽  
Climate Mitigation ◽  
Stage Of Development

&lt;p&gt;Slow progress towards achieving global greenhouse gas emissions targets significantly increases the likelihood that future climate efforts may require not only emissions cuts but also direct climate mitigation via negative emissions technologies (IPCC AR5). Currently, such technologies exist at only a nascent stage of development, with significant uncertainties regarding their feasibility, cost, and potential unintended consequences and/or co-benefits.&lt;/p&gt;&lt;p&gt;Coastal enhanced weathering of olivine (CEWO) has been suggested as one potential pathway for achieving net negative CO&lt;sub&gt;2&lt;/sub&gt; emissions at scale. CEWO involves the mining of olivine-rich ultramafic rocks (such as dunite) for incorporation during beach augmentation and restoration work. While grinding this rock into increasingly fine particle sizes is essential for increasing its surface area and reactivity, this step is also costly and energetically expensive. CEWO attempts to minimize this cost and energy penalty by relying on wave and tidal action to provide ongoing physical weathering of olivine grains once distributed on beaches. Laboratory experiments and carbon emissions assessments of CEWO suggest that these approaches may be technically feasible and carbon negative, but significant uncertainties remain regarding the real-world kinetics of coastal olivine dissolution. Furthermore, concerns about the fate and ecological impact of nickel (Ni) and chromium (Cr)&amp;#8212;potentially toxic trace metals found in olivine&amp;#8212;require careful evaluation.&lt;/p&gt;&lt;p&gt;In 2019, Project Vesta was established as a nonprofit, philanthropically funded effort to evaluate the technical feasibility and ecological impacts of CEWO through a dedicated research program ultimately culminating in small-scale, real-world field trials of CEWO. This presentation will provide an overview and discussion of our overall research strategy, share insights from interim modeling and mesocosm experiments designed to ensure the practicality and safety of future field experiments, and explain our approach for ensuring transparent, responsible, and ethical research oversight and governance.&lt;/p&gt;

scholarly journals Phylogenetic Analysis of Downy Mildew Pathogens of Opium Poppy and PCR-Based In Planta and Seed Detection of Peronospora arborescens

2007 ◽  
Vol 97 (11) ◽  
pp. 1380-1390 ◽  
Author(s):  
Blanca B. Landa ◽  
Miguel Montes-Borrego ◽  
Francisco J. Muñoz-Ledesma ◽  
Rafael M. Jiménez-Díaz
Keyword(s):  
Downy Mildew ◽  
Field Experiments ◽  
Phylogenetic Analyses ◽  
Its Region ◽  
Epidemiological Studies ◽  
Papaver Somniferum ◽  
Opium Poppy ◽  
Recent Common Ancestor ◽  
In Planta ◽  
Commercial Seed

Severe downy mildew diseases of opium poppy (Papaver somniferum) can be caused by Peronospora arborescens and P. cristata, but differentiating between the two pathogens is difficult because they share morphological features and a similar host range. In Spain, where severe epidemics of downy mildew of opium poppy have occurred recently, the pathogen was identified as P. arborescens on the basis of morphological traits. In this current study, sequence homology and phylogenetic analyses of the internal transcribed spacer regions (ITS) of the ribosomal DNA (rDNA) were carried out with DNA from P. arborescens and P. cristata from diverse geographic origins, which suggested that only P. arborescens occurs in cultivated Papaver somniferum in Spain. Moreover, analyses of the rDNA ITS region from 27 samples of downy-mildew-affected tissues from all opium-poppy-growing regions in Spain showed that genetic diversity exists within P. arborescens populations in Spain and that these are phylogenetically distinct from P. cristata. P. cristata instead shares a more recent, common ancestor with a range of Peronospora species that includes those found on host plants that are not members of the Papaveraceae. Species-specific primers and a PCR assay protocol were developed that differentiated P. arborescens and P. cristata and proved useful for the detection of P. arborescens in symptomatic and asymptomatic opium poppy plant parts. Use of these primers demonstrated that P. arborescens can be transmitted in seeds and that commercial seed stocks collected from crops with high incidence of the disease were frequently infected. Field experiments conducted in microplots free from P. arborescens using seed stocks harvested from infected capsules further demonstrated that transmission from seedborne P. arborescens to opium poppy plants can occur. Therefore, the specific-PCR detection protocol developed in this study can be of use for epidemiological studies and diagnosing the pathogen in commercial seed stocks; thus facilitating the sanitary control of the disease and avoidance of the pathogen distribution in seeds.

Non-Linear Space-Time Evolution of Wave Groups With a High Crest

2003 ◽  
Author(s):  
Felice Arena ◽  
Francesco Fedele
Keyword(s):  
Time Evolution ◽  
Field Experiments ◽  
Surface Displacement ◽  
Fixed Time ◽  
Space Time ◽  
Second Order ◽  
Small Scale ◽  
Free Surface Displacement ◽  
Non Linear ◽  
Space Time Evolution

The theory of quasi-determinism, for the mechanics of linear three-dimensional waves, was obtained by Boccotti in the eighties. The first formulation of the theory deals with the largest crest amplitude; the second formulation deals with the largest wave height. The theory was verified in the nineties with some small-scale field experiments. In this paper the first formulation of Boccotti’s theory, valid for the space-time domain, is extended to the second order. The analytical expressions of the non-linear free surface displacement and velocity potential are obtained. Therefore the space-time evolution of a wave group, to the second-order in a Stokes expansion, when a very large crest occurs at a fixed time and location, is investigated. Finally the second-order probability of exceedance of the crest amplitude is obtained, as a function of two deterministic parameters.

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