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Combined heat and power systems: economic and policy barriers to growth
Get PDFBackground: Combined Heat and Power (CHP) systems can provide a range of benefits to users with regards to efficiency, reliability, costs and environmental impact. Furthermore, increasing the amount of electricity generated by CHP systems in the United States has been identified as having significant potential for impressive economic and environmental outcomes on a national scale. Given the benefits from increasing the adoption of CHP technologies, there is value in improving our understanding of how desired increases in CHP adoption can be best achieved. These obstacles are currently understood to stem from regulatory as well as economic and technological barriers. In our research, we answer the following questions: Given the current policy and economic environment facing the CHP industry, what changes need to take place in this space in order for CHP systems to be competitive in the energy market? Methods: We focus our analysis primarily on Combined Heat and Power Systems that use natural gas turbines. Our analysis takes a two-pronged approach. We first conduct a statistical analysis of the impact of state policies on increases in electricity generated from CHP system. Second, we conduct a Cost-Benefit analysis to determine in which circumstances funding incentives are necessary to make CHP technologies cost-competitive. Results: Our policy analysis shows that regulatory improvements do not explain the growth in adoption of CHP technologies but hold the potential to encourage increases in electricity generated from CHP system in small-scale applications. Our Cost-Benefit analysis shows that CHP systems are only cost competitive in large-scale applications and that funding incentives would be necessary to make CHP technology cost-competitive in small-scale applications. Conclusion: From the synthesis of these analyses we conclude that because large-scale applications of natural gas turbines are already cost-competitive, policy initiatives aimed at a CHP market dominated primarily by large-scale (and therefore already cost-competitive) systems have not been effectively directed. Our recommendation is that for CHP technologies using natural gas turbines, policy focuses should be on increasing CHP growth in small-scale systems. This result can be best achieved through redirection of state and federal incentives, research and development, adoption of smart grid technology, and outreach and education.</p
Data from: Local adaptation is highest in populations with stable long-term growth
No full textTheory suggests that the drivers of demographic variation and local adaptation are shared and may feedback on one other. Despite some evidence for these links in controlled settings, the relationship between local adaptation and demography remains largely unexplored in natural conditions. Using 10 years of demographic data and two reciprocal transplant experiments, we tested predictions about the relationship between the magnitude of local adaptation and demographic variation (population growth rates and their elasticities to vital rates) across 10 populations of a well-studied annual plant. In both years, we found a strong unimodal relationship between mean home-away local adaptation and stochastic population growth rates. Other predicted links were either weakly or not supported by our data. Our results suggest that declining and rapidly growing populations exhibit reduced local adaptation, potentially due to maladaptation and relaxed selection, respectively
Key Role of the Ocean Western Boundary currents in shaping the Northern Hemisphere climate
Get PDFThe individual impact of North Atlantic and Pacific Ocean Western Boundary Currents (OWBCs) on the tropospheric circulation has recently been studied in depth. However, their simultaneous role in shaping the hemisphere-scale wintertime troposphere/stratosphere-coupled circulation and its variability have not been considered. Through semi-idealized Atmospheric General-Circulation-Model experiments, we show that the North Atlantic and Pacific OWBCs jointly maintain and shape the wintertime hemispheric circulation and its leading mode of variability Northern Annular Mode (NAM). The OWBCs energize baroclinic waves that reinforce quasi-annular hemispheric structure in the tropospheric eddy-driven jetstreams and NAM variability. Without the OWBCs, the wintertime NAM variability is much weaker and its impact on the continental and maritime surface climate is largely insignificant. Atmospheric energy redistribution caused by the OWBCs acts to damp the near-surface atmospheric baroclinicity and compensates the associated oceanic meridional energy transport. Furthermore, the OWBCs substantially weaken the wintertime stratospheric polar vortex by enhancing the upward planetary wave propagation, and thereby affecting both stratospheric and tropospheric NAM-annularity. Whereas the overall impact of the extra-tropical OWBCs on the stratosphere results mainly from the Pacific, the impact on the troposphere results from both the Pacific and Atlantic OWBCs
The Survival Line: A Case Study in Anti-Carceral Community-Based Hotline Work
Get PDFCommunity members seeking alternatives to policing have played a substantive role in promoting safety and responding to harm for decades. The Survival Line was formed as a volunteer-run hotline to respond to community members’ concerns about neighborhood crime or police misconduct. It was established in the summer of 1970 as a mechanism for gathering data while also referring callers to community resources like pro bono attorneys and low-cost social services. It ran as a 24/7 hotline staffed entirely by volunteers from the Action for Survival coalition, a group of community-based organizations, which included the Chicago Urban League. Using historical analytic methods, this study asks the following: what function did this citizen-run hotline serve in 1970s Chicago? This study mobilizes archival research methods to analyze call records, meeting minutes, publicity materials, and internal memos from the Chicago Urban League and its Survival Line archives. This archival analysis found that the Survival Line served multiple functions; it was a non-state response to urban crises, a vehicle for Black solidarity, and a mechanism for gathering data on crime and police misconduct in the city. By functioning as an alternative to policing and state responses to crime, a vehicle for Black neighborhood solidarity, and a data collection mechanism, the Survival Line was at the core of an impactful micropolitical intervention upon urban crises in 1970s Chicago. As a historical example of community-driven violence and crisis response, this hotline has implications for contemporary social work—specifically for direct practice, community organizing, program design and evaluation, and community-based participatory research
Microbiota does not influence tumor development in two models of heritable cancer
Get PDFMicrobial impact on tumorigenesis of heritable cancers proximal to the gut is well-documented. Whether the microbiota influences cancers arising from inborn mutations at sites distal to the gut is undetermined. Using two models of heritable cancer, Trp53-deficient mice and Wnt1-transgenic mice, and a gnotobiotic approach, we found the microbiota to be inconsequential for tumor development. This work furthers our understanding of the degree of the microbial impact on tumor development
Predicting Aggregate Choice from Preconscious Processing
Get PDFPredicting behavior is both challenging and valuable. While previous research has provided evidence for predicting choice through examining neural activity, incorporating behavioral evidence could offer deeper insights into the roles of preconscious and conscious processes in shaping individual and aggregate decision-making. The present study is designed to test whether preconscious processes can predict choice at both individual and aggregate levels. An in-lab experiment of 36 subjects using “breaking continuous flash suppression” method was conducted. In the first part of the study, subjects were instructed to identify a visually suppressed NFT artwork per trial. In the second part, subjects were asked to choose their preferred artwork between pairs of artworks. The results showed no significant association between reaction time and price of artworks, nor significant association between reaction time and individual preference. These findings suggest that current method may require further refinement to effectively investigate the influence of preconscious and conscious processes in decision-making. Future research should refine methodologies, ensuring demographic alignment and integrating behavioral and neural methods to better assess preconscious influences on choice
Characterizing Genetic Regulatory Effects on Gene Expression in Response to Environmental Perturbations
No full textGenome-wide association studies (GWAS) have made significant strides in identifying genetic loci associated with complex traits and diseases. However, most of these loci lie outside of coding regions and their molecular mechanisms remain largely unexplained. Mapping expression quantitative trait loci (eQTLs) has emerged as a key tool for uncovering regulatory mechanisms of non-coding loci by linking genetic variants to gene expression changes. Despite the progress made by large-scale eQTL studies, many GWAS loci are not explained by existing eQTL data from steady-state healthy samples. In this dissertation, I explore context-dependent genetic effects that are often overlooked in conventional eQTL studies. I leverage two different models to investigate how genetic variants influence gene expression in response to environmental perturbations and their potential for enhancing the interpretation of disease-associated loci. In Chapter II, I investigate genetic regulatory effects in response to a high-cholesterol, high-fat diet in baboons. By analyzing RNA-sequencing data from metabolically relevant tissues of 99 baboons, I identified hundreds of diet-responsive eQTLs. These diet-responsive eQTLs exhibit distinct signatures of regulatory complexity, evolutionary constraint, and functional enrichment that distinguish them from standard, steady-state eQTLs. The human orthologs associated with diet-responsive eQTLs are enriched for GWAS genes associated with human metabolic traits, suggesting that context-responsive eQTLs with more complex regulatory effects are likely to explain GWAS hits that do not seem to overlap with standard eQTLs. To more efficiently explore gene-environment (GxE) interactions across diverse cellular contexts, I leverage heterogeneous differentiating cultures (HDCs) as a flexible and scalable system. In Chapter III, I perturbed a broad array cell types from 51 individuals with chemical exposures: ethanol, caffeine, and nicotine. With single-cell RNA-sequencing data from 1.4 million cells, I identified hundreds of dynamic eQTLs that regulate molecular responses to perturbation across multiple cellular contexts. Similar to diet-responsive eQTLs in baboons, response eQTLs in HDCs also show different properties from standard eQTLs. They are enriched in distal enhancers and are linked to genes that experienced strong selective constraint, involve in complex regulatory landscapes and diverse biological functions. Furthermore, response eQTLs are more likely than standard eQTLs to colocalize with GWAS signals for complex traits, suggesting their critical role in mediating the effects of disease-associated loci. Together, this work demonstrates that context-responsive eQTLs—whether induced by dietary changes in baboons or chemical exposures in HDCs—exhibit unique characteristics that align more closely with disease-associated loci from GWAS. The findings from this dissertation highlight the value of considering GxE interactions in uncovering the functional relevance of non-coding genetic variants, particularly those that fail to exhibit regulatory potential under steady-state conditions. By expanding the scope of eQTL studies to include diverse environmental and biological contexts, we will identify more context-dependent and functionally relevant regulatory loci, thereby moving closer to translating GWAS findings into actionable insights for human health
Contrasting Patterns of Climatic Niche Divergence in <i>Trebouxia</i>—A Clade of Lichen-Forming Algae
Get PDFLichen associations are overwhelmingly supported by carbon produced by photosynthetic algal symbionts. These algae have diversified to occupy nearly all climates and continents; however, we have a limited understanding of how their climatic niches have evolved through time. Here we extend previous work and ask whether phylogenetic signal in, and the evolution of, climatic niche, varies across climatic variables, phylogenetic scales, and among algal lineages in Trebouxia—the most common genus of lichen-forming algae. Our analyses reveal heterogeneous levels of phylogenetic signal across variables, and that contrasting models of evolution underlie the evolution of climatic niche divergence. Together these analyses demonstrate the variable processes responsible for shaping climatic tolerance in Trebouxia, and provide a framework within which to better understand potential responses to climate change-associated perturbations. Such predictions reveal a disturbing trend in which the pace at which modern climate change is proceeding will vastly exceed the rate at which Trebouxia climatic niches have previously evolved
Science Under Threat in the United States: How scientists and institutions should respond
Get PDFIndividual researchers and university leaders need to make the case for science to their elected representatives and to the public at large