University of Maine

About: University of Maine is a education organization based out in Orono, Maine, United States. It is known for research contribution in the topics: Population & Ice sheet. The organization has 8637 authors who have published 16932 publications receiving 590124 citations. The organization is also known as: University of Maine at Orono.

Intertemporal Permit Trading for the Control of Greenhouse Gas Emissions

Abstract: This paper integrates two themes in the intertemporal permitliterature through the construction of an intertemporal bankingsystem for a pollutant that creates both stock and flow damages. A permit banking system for the special case of a pollutant thatonly causes stock damages is also developed. This latter,simpler case corresponds roughly to the greenhouse gas emissionreduction regime proposed by the U.S. Department of State as ameans of fulfilling the U.S. commitment to the FrameworkConvention on Climate Change. This paper shows that environmentalregulators can achieve the socially optimal level of emissionsand output through time by setting the correct total sum ofallowable emissions, and specifying the correct intertemporaltrading ratio for banking and borrowing. For the case ofgreenhouse gases, we show that the optimal growth rate of permitprices, and therefore the optimal intertemporal trading rate, hasthe closed-form solution equal to the ratio of current marginalstock damages to the discounted future value of marginal stockdamages less the decay rate of emissions in the atmosphere. Given a non-optimal negotiated emission path we then derive apermit banking system that has the potential to lower net socialcosts by adjusting the intertemporal trading ratio taking intoaccount the behavior of private agents. We use a simplenumerical simulation model to illustrate the potential gains fromvarious possible banking systems.

Ecological genetics in the north atlantic: environmental gradients and adaptation at specific loci

Abstract: The North Atlantic intertidal community provides a rich set of organismal and environmental material for the study of ecological genetics. Clearly defined environmental gradients exist at multiple spatial scales: there are broad latitudinal trends in temperature, meso-scale changes in salinity along estuaries, and smaller scale gradients in desiccation and temperature spanning the intertidal range. The geology and geography of the American and European coasts provide natural replication of these gradients, allowing for population genetic analyses of parallel adaptation to environmental stress and heterogeneity. Statistical methods have been developed that provide genomic neutrality tests of population differentiation and aid in the process of candidate gene identification. In this paper, we review studies of marine organisms that illustrate associations between an environmental gradient and specific genetic markers. Such highly differentiated markers become candidate genes for adaptation to the environmental factors in question, but the functional significance of genetic variants must be comprehensively evaluated. We present a set of predictions about locus-specific selection across latitudinal, estuarine, and intertidal gradients that are likely to exist in the North Atlantic. We further present new data and analyses that support and contradict these simple selection models. Some taxa show pronounced clinal variation at certain loci against a background of mild clinal variation at many loci. These cases illustrate the procedures necessary for distinguishing selection driven by internal genomic vs. external environmental factors. We suggest that the North Atlantic intertidal community provides a model system for identifying genes that matter in ecology due to the clarity of the environmental stresses and an extensive experimental literature on ecological function. While these organisms are typically poor genetic and genomic models, advances in comparative genomics have provided access to molecular tools that can now be applied to taxa with well-defined ecologies. As many of the organisms we discuss have tight physiological limits driven by climatic factors, this synthesis of molecular population genetics with marine ecology could provide a sensitive means of assessing evolutionary responses to climate change.

Literacy by Design A Universal Design for Learning Approach for Students With Significant Intellectual Disabilities

Abstract: Literacy instruction for students with significant intellectual disabilities traditionally emphasizes isolated skills instruction focusing on sight words and basic vocabulary. Recent research suggests these students benefit from high-quality instruction that includes comprehension and storybook reading. This study examined the effect of a technology-based universal design for learning (UDL) approach to literacy instruction, Literacy by Design (LBD), on the reading achievement of 16 students with significant intellectual disabilities in Grades K–2. The LBD approach emphasizes reading for meaning, combining UDL-scaffolded e-books and letter and word recognition software. Nine teachers received training in research-based literacy practices. Of these, five received LBD training and implemented it four to five times weekly. Controlling for initial reading achievement, the LBD group made significantly greater gains on the Woodcock–Johnson Test of Achievement III Passage Comprehension subtest. Implications for research and practice in beginning reading instruction for children with significant intellectual disabilities are discussed.