Although the diffusion of solar electricity has been swift worldwide, there is little certainty regarding the adoption of this technology on rooftops, in locations where there is no specific policy ...on renewables in place. In such cases, there is much uncertainty regarding the effect of solar penetration on electricity prices to consumers and on the reduction of electricity demand from the grid. The penetration of solar in the residential sector – which in some cases accounts for about 40% of the country's total electricity demand – may have a tremendous impact on incumbent utilities and the industry as a whole. Much research has been devoted to assessing the effect of policy on the diffusion of renewables but not much work about the developing world is known, particularly in those nations where institutional arrangements do not favour these technologies. Using system dynamics, this paper examines these issues, considering the diffusion of rooftop solar both with a battery support system, and also without any type of storage system. An important conclusion is that policy is essential for system sustainability when PV diffusion is taking place.
The technology shift from fossil-fuelled systems to renewable energies has been promoted by governments with the purpose of decarbonising the power industry. However, rapid technology progress has ...prompted disruptive changes that transformed market structures. Incumbent electricity utilities, particularly those based on fossil-fuel plant, are shifting from their stable and predictable situation to confront challenges from those that offer alternative energy services. In this new environment, the industry will benefit from mid- to long-term sector foresight.
The paper studies the potential impact of renewable energy sources (RES) on electricity systems, specifically on the generation and distribution businesses. For this purpose, a fairly detailed and integrated supply and demand-based system dynamics model has been built to quantify the extent of their potential impact; the model disaggregates the household sector, which may generate a significant part of its electricity using rooftop solar energy. This is illustrated by examining a utility engaged in the generation and distribution businesses in the Colombian electricity market. Through simulation runs, this paper concludes that, subject to policy and all other things remaining equal, solar rooftop generation is a major threat for utilities; while the generation business is most affected in the short-term, the distribution business is the one most impacted in the long-term, and jointly they may induce the utility “death spiral”.
As the electricity industry is changing worldwide, the swift expansion of basic forms of Distributed Generation (DG), particularly photovoltaic deployment, threatens the current utility business ...models that during the transitional stages may challenge the reliability of electricity systems and societal welfare. These findings are matters of major concern to policy makers as the shift towards more decentralized power systems must be sustainable, and although this brings great opportunities, it also pauses important challenges. The transition calls for policy and regulation attention. For some researchers, DG development should be accompanied with design changes to distribution tariffs, the addition of connection charge and modifications to Net Metering, while for others, certain of these measures could discourage DG investments. In this context and given multiple uncertainties, the authors propose a system dynamics model to examine the effect of the diffusion of Photovoltaic technology on the revenues of utilities and customers. The paper concludes that for the Colombian case, it is possible under certain conditions to attain a balance between social welfare and the aversion of the utility death spiral through systemic interventions.
•Diffusion of solar PV is taking place in all electricity markets worldwide.•Customers are benefiting from solar PV.•In this context, the utility death spiral is a challenge.•Systemic policy intervention facilitate sustainable PV diffusion.
Eggs are sources of protein, fats and micronutrients that play an important role in basic nutrition. However, eggs are traditionally associated with adverse factors in human health, mainly due to ...their cholesterol content. Nowadays, however, it is known that the response of cholesterol in human serum levels to dietary cholesterol consumption depends on several factors, such as ethnicity, genetic makeup, hormonal factors and the nutritional status of the consumer. Additionally, in recent decades, there has been an increasing demand for functional foods, which is expected to continue to increase in the future, owing to their capacity to decrease the risks of some diseases and socio-demographic factors such as the increase in life expectancy. This work offers a brief overview of the advantages and disadvantages of egg consumption and the potential market of functional eggs, and it explores the possibilities of the development of functional eggs by technological methods.
Salmonella is a major foodborne pathogen with a complex nomenclature. This genus is composed of two species, S. enterica and S. bongori. S. enterica is divided into six subspecies. S. enterica ...subspecies enterica is composed of more than 1500 serotypes with some of great importance, such as S. Typhimurium and S. Enteritidis. S. enterica subsp. enterica is responsible of more than 99% of human salmonellosis and therefore it is widely studied. However, the non-enterica subspecies of S. enterica have been little studied. These subspecies are considered to be related to cold-blooded animals and their pathogenicity is very limited. Phenotype and genotype information generated from different studies of non-enterica subspecies reveal poor ability to invade host cells and the absence or modification of important virulence factors. Also, the great majority of human infections due to non-enterica subspecies are related to a previous depressed immune system. Therefore, we propose to treat these subspecies only as opportunistic pathogens. For establish this premise, the present review evaluated, among other things, the genomic characteristics, prevalence, antimicrobial resistance and reported human cases of the non-enterica subspecies.
•This paper assesses through simulation the GB Electricity Market Reform.•A system dynamics model supports the analysis of long-term effects of policy.•Lessons from simulation indicate the ...effectiveness of policy.
The British government is implementing fully its novel Electricity Market Reform (GB EMR). Its objective, in line with European directives, aims at replacing existing nuclear and coal plant with low-carbon systems, to deliver reliable and affordable power. Though the GB EMR has proposed several policy instruments for meeting its objectives, and the academic literature has discussed the main issues, no known report includes a comprehensive and dynamic simulation exercise that assesses the extent of this profound and important initiative. This paper presents a system dynamics model that supports analysis of long-term effects of the various policy instruments that have been proposed in the GB EMR, focusing on environmental quality, security of supply and economic sustainability. Using lessons learned from simulation, the paper concludes that effectively achieving the GB EMR objectives requires this comprehensive intervention or a similar one that includes the promotion of low carbon electricity generation through the simultaneous implementation of various direct and indirect incentives, such as a carbon price floor, a Feed in Tariff (FIT) and a capacity mechanism.
Human gut microbiota plays an important role in several metabolic processes and human diseases. Various dietary factors, including complex carbohydrates, such as polysaccharides, provide abundant ...nutrients and substrates for microbial metabolism in the gut, affecting the members and their functionality. Nowadays, the main sources of complex carbohydrates destined for human consumption are terrestrial plants. However, fresh water is an increasingly scarce commodity and world agricultural productivity is in a persistent decline, thus demanding the exploration of other sources of complex carbohydrates. As an interesting option, marine seaweeds show rapid growth and do not require arable land, fresh water or fertilizers. The present review offers an objective perspective of the current knowledge surrounding the impacts of seaweeds and their derived polysaccharides on the human microbiome and the profound need for more in-depth investigations into this topic. Animal experiments and in vitro colonic-simulating trials investigating the effects of seaweed ingestion on human gut microbiota are discussed.
Leprosy in the 21st century White, Cassandra; Franco-Paredes, Carlos
Clinical microbiology reviews
28, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Despite significant improvements in leprosy (Hansen's disease) treatment and outlook for patients since the introduction of multidrug therapy (MDT) 3 decades ago, the global incidence remains high, ...and patients often have long-term complications associated with the disease. In this article, we discuss recent findings related to genetics, susceptibility, and disease reservoirs and the implications of these findings for Hansen's disease control and health outcomes for patients. We describe the continued difficulties associated with treatment of inflammatory episodes known as "leprosy reactions," which cause much of the disability associated with the disease and can affect people for many years after MDT is complete. We also discuss some of the contemporary challenges for physicians and patients, including international and internal migration of people affected by the disease. We suggest some important areas of focus for future Hansen's disease research.
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