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Publisher: Oxford : Elsevier ×

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Now showing 1 - 4 of 4
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    Why the sustainable provision of low-carbon electricity needs hybrid markets
    (Oxford : Elsevier, 2022) Keppler, Jan Horst; Quemin, Simon; Saguan, Marcelo
    Deep decarbonization of energy systems poses considerable challenges to electricity markets and there is a growing consensus that an energy-only design based on short-term marginal cost pricing cannot deliver adequate levels of investment and long-term coordination across actors and sectors. Based on the instructive example of the evolution of European electricity market designs, we discuss several shortcomings of energy-only markets and illustrate how ad-hoc policies that intend to address them have limitations of their own, notably a lack of systemwide coordination. Second, we describe how the sheer scale and nature of deep decarbonization targets requiring massive investment in capital-intensive low-carbon technologies exacerbate these issues. Ambitious emission reduction targets thus require an evolution of market design towards hybrid regimes. Hybrid markets separate long-term investment decisions from short-term operations through a balanced and differentiated use of competitive and regulatory design elements to coordinate and de-risk investment. Finally, a historical analysis of the evolution of different electricity market designs shows how hybrid markets constitute contemporary forms of long-run marginal cost pricing that are appropriate for meeting deep decarbonization targets with reduced uncertainty and hence lower private and social costs.
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    Updating radical ring-opening polymerisation of cyclic ketene acetals from synthesis to degradation
    (Oxford : Elsevier, 2020) Folini, Jenny; Murad, Wigdan; Mehner, Fabian; Meier, Wolfgang; Gaitzsch, Jens
    Radical ring-opening polymerisation (RROP) of cyclic ketene acetals (CKAs) has gained momentum as it yields polyesters as biodegradable polymers from a radical polymerisation. In order to advance the polymerisation, some of its major limitations were addressed in the research presented, focussing on the four mainly used CKAs in modern research on RROP. Monomer synthesis has been updated towards a cobalt/TMSCl-based system that was performed reliably on several monomers at room temperature. Calculations using the density functional theory (DFT) revealed that the ring-opening step is energetically hampered in comparison to a ring-retaining reaction, which explained the challenges faced to promote the ring-opening reaction. Higher molecular weights up to four times the values reached by thermally initiated polymerisation were obtained by exploiting UV light and ultrasound as alternative methods to facilitate the polymerisation. The reaction procedure also influenced thermal properties of the polymers, which in turn affected the enzymatic degradation of nanoparticles based on those polymers. Altogether, the present study offers a holistic update to enhance the RROP of CKAs.
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    Spatiotemporal variation in risk of Shigella infection in childhood: a global risk mapping and prediction model using individual participant data
    (Oxford : Elsevier, 2023) Badr, Hamada S.; Colston, Josh M.; Nguyen, Nhat-Lan H.; Chen, Yen Ting; Burnett, Eleanor; Ali, Syed Asad; Rayamajhi, Ajit; Satter, Syed M.; Van Trang, Nguyen; Eibach, Daniel; Krumkamp, Ralf; May, Jürgen; Adegnika, Ayola Akim; Manouana, Gédéon Prince; Kremsner, Peter Gottfried; Chilengi, Roma; Hatyoka, Luiza; Debes, Amanda K.; Ateudjieu, Jerome; Faruque, Abu S. G.; Hossain, M. Jahangir; Kanungo, Suman; Kotloff, Karen L; Mandomando, Inácio; Nisar, M. Imran; Omore, Richard; Sow, Samba O.; Zaidi, Anita K. M.; Lambrecht, Nathalie; Adu, Bright; Page, Nicola; Platts-Mills, James A.; Mavacala Freitas, Cesar; Pelkonen, Tuula; Ashorn, Per; Maleta, Kenneth; Ahmed, Tahmeed; Bessong, Pascal; Bhutta, Zulfiqar A.; Mason, Carl; Mduma, Estomih; Olortegui, Maribel P.; Peñataro Yori, Pablo; Lima, Aldo A. M.; Kang, Gagandeep; Humphrey, Jean; Ntozini, Robert; Prendergast, Andrew J.; Okada, Kazuhisa; Wongboot, Warawan; Langeland, Nina; Moyo, Sabrina J.; Gaensbauer, James; Melgar, Mario; Freeman, Matthew; Chard, Anna N.; Thongpaseuth, Vonethalom; Houpt, Eric; Zaitchik, Benjamin F.; Kosek, Margaret N.
    BACKGROUND: Diarrhoeal disease is a leading cause of childhood illness and death globally, and Shigella is a major aetiological contributor for which a vaccine might soon be available. The primary objective of this study was to model the spatiotemporal variation in paediatric Shigella infection and map its predicted prevalence across low-income and middle-income countries (LMICs). METHODS: Individual participant data for Shigella positivity in stool samples were sourced from multiple LMIC-based studies of children aged 59 months or younger. Covariates included household-level and participant-level factors ascertained by study investigators and environmental and hydrometeorological variables extracted from various data products at georeferenced child locations. Multivariate models were fitted and prevalence predictions obtained by syndrome and age stratum. FINDINGS: 20 studies from 23 countries (including locations in Central America and South America, sub-Saharan Africa, and south and southeast Asia) contributed 66 563 sample results. Age, symptom status, and study design contributed most to model performance followed by temperature, wind speed, relative humidity, and soil moisture. Probability of Shigella infection exceeded 20% when both precipitation and soil moisture were above average and had a 43% peak in uncomplicated diarrhoea cases at 33°C temperatures, above which it decreased. Compared with unimproved sanitation, improved sanitation decreased the odds of Shigella infection by 19% (odds ratio [OR]=0·81 [95% CI 0·76-0·86]) and open defecation decreased them by 18% (OR=0·82 [0·76-0·88]). INTERPRETATION: The distribution of Shigella is more sensitive to climatological factors, such as temperature, than previously recognised. Conditions in much of sub-Saharan Africa are particularly propitious for Shigella transmission, although hotspots also occur in South America and Central America, the Ganges-Brahmaputra Delta, and the island of New Guinea. These findings can inform prioritisation of populations for future vaccine trials and campaigns. FUNDING: NASA, National Institutes of Health-The National Institute of Allergy and Infectious Diseases, and Bill & Melinda Gates Foundation.