74 research outputs found
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Tariffs Can Be Structured to Encourage Photovoltaic Energy
The solar power market is growing at a quickening pace, fueled by an array of national and local initiatives and policies aimed at improving the value proposition of customer-sited photovoltaic (PV) systems. Though these policies take many forms, they commonly include up-front capital cost rebates or ongoing production incentives, supplemented by net metering requirements to ensure that customer-sited PV systems offset the full retail rate of the customer-hosts. Somewhat less recognized is the role of retail rate design, beyond net metering, on the customer-economics of grid-connected PV. Over the life of a PV system, utility bill savings represent a substantial portion of the overall economic value received by the customer. At the same time, the design of retail electricity rates, particularly for commercial and industrial customers, can vary quite substantially. Understanding how specific differences in rate design affect the value of customer-sited PV is therefore essential to supporting the continued growth of this market
The Impact of Retail Rate Structures on the Economics ofCustomer-Sited PV: A Study of Commercial Installations inCalifornia
We analyze the impact of retail rate design on the economics of grid-connected commercial photovoltaic (PV) systems in California. The analysis is based on 15-minute interval building load and PV production data for 24 commercial PV installations in California, spanning a diverse set of building load shapes and geographic locations. We derive the annual bill savings per kWh generated for each PV system, under each of 21 distinct retail rates currently offered by the five largest utilities in California. We identify and explain variation in the value of bill savings attributable to differences in the structure of demand and energy charges across rates, as well as variation attributable to other factors, such as the size of the PV system relative to building load, the specific shape of the PV production profile, and the customer load profile. We also identify the optimal rate for each customer, among those rates offered as alternatives to one another, and show how the decision is driven in large measure by the size of the PV system relative to building load. The findings reported here may be of value to regulators and utilities responsible for designing retail rates, as well as to customers and PV retailers who have a need to estimate the prospective bill savings of PV systems
Turning G Proteins On and Off Using Peptide Ligands
Intracellular Gα subunits represent potential therapeutic targets for a number of diseases. Here we describe three classes of new molecules that modulate G protein signaling by direct targeting of Gα. Using messenger RNA display, we have identified unique peptide sequences that bind Gα_(i1). Functionally, individual peptides were found that either enhance or repress basal levels of G protein-activated inwardly rectifying potassium (GIRK) channel signaling, a downstream effector of G protein activation, indicating that the peptides directly turn G proteins on or off in vivo. A third functional class acts as a signaling attenuator; basal GIRK channel activity is unaffected but responses to repeated G protein activation are reduced. These data demonstrate that G protein-directed ligands can achieve physiological effects similar to those resulting from classical receptor targeting and may serve as leads for developing new classes of therapeutics
The value of indirect ties in citation networks:SNA analysis with OWA operator weights
This paper seeks to advance the theory and practice of the dynamics of complex networks in relation to direct and indirect citations. It applies social network analysis (SNA) and the ordered weighted averaging operator (OWA) to study a patent citations network. So far the SNA studies investigating long chains of patents citations have rarely been undertaken and the importance of a node in a network has been associated mostly with its number of direct ties. In this research OWA is used to analyse complex networks, assess the role of indirect ties, and provide guidance to reduce complexity for decision makers and analysts. An empirical example of a set of European patents published in 2000 in the renewable energy industry is provided to show the usefulness of the proposed approach for the preference ranking of patent citations
The global abundance of tree palms
Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191 ha) and quantified tree palm (i.e., â„10 cm diameter at breast height) abundance relative to coâoccurring nonâpalm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of longâterm climate stability. Lifeâform diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many nonâtree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of aboveâground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests
Phylogenetic classification of the world's tropical forests
Knowledge about the biogeographic affinities of the worldâs tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of species inventory data, now allow for global biogeographic analyses that take species evolutionary distance into account. Here we present a classification of the worldâs tropical forests based on their phylogenetic similarity. We identify five principal floristic regions and their floristic relationships: (i) Indo-Pacific, (ii) Subtropical, (iii) African, (iv) American, and (v) Dry forests. Our results do not support the traditional neo- versus paleotropical forest division but instead separate the combined American and African forests from their Indo-Pacific counterparts. We also find indications for the existence of a global dry forest region, with representatives in America, Africa, Madagascar, and India. Additionally, a northern-hemisphere Subtropical forest region was identified with representatives in Asia and America, providing support for a link between Asian and American northern-hemisphere forests.</p
Ectopic pregnancy secondary to in vitro fertilisation-embryo transfer: pathogenic mechanisms and management strategies
INHERITANCE OF REACTION TO DIPLODIA ZEAE (SCHW.) LEV. IN ZEA MAYS L. EARS
Abstract not availabl
Experimental investigation of post-tensioned cables for foundation repair in historical structures
Whenever a historical structure is destroyed or significantly changed, it is a loss of history. Not only do we lose a piece of history, damaged historical structures can collapse and cause a loss of human life, so it is important to save them as early as possible. Foundation repairs or foundation issues often result in the foundation being replaced, and in doing so there is the potential for significant damage occurring to the foundation during the course of repairs. Using a technique similar to external prestressing, this thesis proposes that it is feasible to repair and strengthen existing structural foundation, by using a practice used in bridges when the capacity must be increased past its original design; a foundation can be repaired and strengthened. Similar to how a new beam that is over prestressed will raise the beam in the middle; the technique can allow for sagging or sinking midspan of the slab to be brought to level or reduced. By boring under the foundation and doing repairs out of sight, the damage to the aesthetic appeal of the landmark is minimized, as accomplished through the testing on the model foundation
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