Defective Interfering Viral Particles in Acute Dengue Infections

While much of the genetic variation in RNA viruses arises because of the error-prone nature of their RNA-dependent RNA polymerases, much larger changes may occur as a result of recombination. An extreme example of genetic change is found in defective interfering (DI) viral particles, where large sections of the genome of a parental virus have been deleted and the residual sub-genome fragment is replicated by complementation by co-infecting functional viruses. While most reports of DI particles have referred to studies in vitro, there is some evidence for the presence of DI particles in chronic viral infections in vivo. In this study, short fragments of dengue virus (DENV) RNA containing only key regulatory elements at the 3′ and 5′ ends of the genome were recovered from the sera of patients infected with any of the four DENV serotypes. Identical RNA fragments were detected in the supernatant from cultures of Aedes mosquito cells that were infected by the addition of sera from dengue patients, suggesting that the sub-genomic RNA might be transmitted between human and mosquito hosts in defective interfering (DI) viral particles. In vitro transcribed sub-genomic RNA corresponding to that detected in vivo could be packaged in virus like particles in the presence of wild type virus and transmitted for at least three passages in cell culture. DENV preparations enriched for these putative DI particles reduced the yield of wild type dengue virus following co-infections of C6–36 cells. This is the first report of DI particles in an acute arboviral infection in nature. The internal genomic deletions described here are the most extensive defects observed in DENV and may be part of a much broader disease attenuating process that is mediated by defective viruses

Energy dispersive X-ray fluorescence spectrometric determination of lead after liquid-solid extraction with 1-(2-pyridylazo)-2-naphthol immobilized on silica.

1-(2-Pyridylazo)-2-naphthol (PAN) immobilized on silica has been used to preconcentrate lead (II) in aqueous samples for its determination using Energy Dispersive X-Ray Fluorescence Spectrometry, The optimal conditions for quantitative extraction, viz,, pH, stirring time and aqueous phase volume, were systematically evaluated. The procedure yields reliable results for lead determination in aqueous samples of environmental importance.191303

Time-Varying Value of Energy Efficiency in Michigan

Quantifying the time-varying value of energy efficiency is necessary to properly account for all of its benefits and costs and to identify and implement efficiency resources that contribute to a low-cost, reliable electric system. Historically, most quantification of the benefits of efficiency has focused largely on the economic value of annual energy reduction. Due to the lack of statistically representative metered end-use load shape data in Michigan (i.e., the hourly or seasonal timing of electricity savings), the ability to confidently characterize the time-varying value of energy efficiency savings in the state, especially for weather-sensitive measures such as central air conditioning, is limited. Still, electric utilities in Michigan can take advantage of opportunities to incorporate the time-varying value of efficiency into their planning. For example, end-use load research and hourly valuation of efficiency savings can be used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service (KEMA 2012). In addition, accurately calculating the time-varying value of efficiency may help energy efficiency program administrators prioritize existing offerings, set incentive or rebate levels that reflect the full value of efficiency, and design new programs

Time-Varying Value of Energy Efficiency in Michigan

Quantifying the time-varying value of energy efficiency is necessary to properly account for all of its benefits and costs and to identify and implement efficiency resources that contribute to a low-cost, reliable electric system. Historically, most quantification of the benefits of efficiency has focused largely on the economic value of annual energy reduction. Due to the lack of statistically representative metered end-use load shape data in Michigan (i.e., the hourly or seasonal timing of electricity savings), the ability to confidently characterize the time-varying value of energy efficiency savings in the state, especially for weather-sensitive measures such as central air conditioning, is limited. Still, electric utilities in Michigan can take advantage of opportunities to incorporate the time-varying value of efficiency into their planning. For example, end-use load research and hourly valuation of efficiency savings can be used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service (KEMA 2012). In addition, accurately calculating the time-varying value of efficiency may help energy efficiency program administrators prioritize existing offerings, set incentive or rebate levels that reflect the full value of efficiency, and design new programs

Regulatory Issues and Approaches to Municipal LED Street Lighting Conversions

Municipalities considering energy-efficient light-emitting diode street lights for their jurisdiction face a variety of regulatory issues. This brief describes how cities can successfully address these challenges to achieve multiple advantages. The brief first reviews the structure of street lighting tariffs and the costs and cost assumptions that underlie them. It then lays out pathways that municipalities can take to consider street lighting retrofits if faced by these regulatory barriers. The brief references cases of municipalities’ successes and challenges in pursuing these pathways. For more information, see the resources listed at the end of the brief

Regulatory Issues and Approaches to Municipal LED Street Lighting Conversions

Municipalities considering energy-efficient light-emitting diode street lights for their jurisdiction face a variety of regulatory issues. This brief describes how cities can successfully address these challenges to achieve multiple advantages. The brief first reviews the structure of street lighting tariffs and the costs and cost assumptions that underlie them. It then lays out pathways that municipalities can take to consider street lighting retrofits if faced by these regulatory barriers. The brief references cases of municipalities’ successes and challenges in pursuing these pathways. For more information, see the resources listed at the end of the brief