McIntyre P.J.,University of California at Berkeley |
Thorne J.H.,University of California at Davis |
Dolanc C.R.,University of California at Davis |
Dolanc C.R.,University of Montana |
And 5 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015
We document changes in forest structure between historical (1930s) and contemporary (2000s) surveys of California vegetation through comparisons of tree abundance and size across the state and within several ecoregions. Across California, tree density in forested regions increased by 30% between the two time periods, whereas forest biomass in the same regions declined, as indicated by a 19% reduction in basal area. These changes reflect a demographic shift in forest structure: larger trees (>61 cm diameter at breast height) have declined, whereas smaller trees (<30 cm) have increased. Large tree declines were found in all surveyed regions of California, whereas small tree increases were found in every region except the south and central coast. Large tree declines were more severe in areas experiencing greater increases in climaticwater deficit since the 1930s, based on a hydrologicmodel of water balance for historical climates through the 20th century. Forest composition in California in the last century has also shifted toward increased dominance by oaks relative to pines, a pattern consistent with warming and increased water stress, and also with paleohistoric shifts in vegetation in California over the last 150,000 y.
Franks E.M.,University of Notre Dame |
Cabo L.L.,Mercyhurst University
American Journal of Physical Anthropology | Year: 2014
Traditionally, the study of metric skeletal asymmetry has relied largely on univariate analyses, utilizing ratio transformations when the goal is comparing asymmetries in skeletal elements or populations of dissimilar dimensions. Under this approach, raw asymmetries are divided by a size marker, such as a bilateral average, in an attempt to produce size-free asymmetry indices. Henceforth, this will be referred to as "controlling for size" (see Smith: Curr Anthropol 46 (2005) 249-273). Ratios obtained in this manner often require further transformations to interpret the meaning and sources of asymmetry. This model frequently ignores the fundamental assumption of ratios: the relationship between the variables entered in the ratio must be isometric. Violations of this assumption can obscure existing asymmetries and render spurious results. In this study, we examined the performance of the classic indices in detecting and portraying the asymmetry patterns in four human appendicular bones and explored potential methodological alternatives. Examination of the ratio model revealed that it does not fulfill its intended goals in the bones examined, as the numerator and denominator are independent in all cases. The ratios also introduced strong biases in the comparisons between different elements and variables, generating spurious asymmetry patterns. Multivariate analyses strongly suggest that any transformation to control for overall size or variable range must be conducted before, rather than after, calculating the asymmetries. A combination of exploratory multivariate techniques, such as Principal Components Analysis, and confirmatory linear methods, such as regression and analysis of covariance, appear as a promising and powerful alternative to the use of ratios. © 2014 Wiley Periodicals, Inc.
News Article | October 28, 2016
The Institute for Freedom & Community at St. Olaf College will host ‘“Who’s in Your Wallet?” Hamilton, Jackson, Tubman, and the Presidential Election’ on October 20 as part of The Institute’s 2016-17 event series. This event is free, open to the public and hosted at St. Olaf College, located 45 minutes south of the Twin Cities. “Who’s in Your Wallet?” will address the controversy over faces on the fronts of the $10 and $20 bills, which provides an interesting backdrop on how we think about the 2016 presidential election and broader issues in American society. A panel of three visiting speakers, Michael Federici, Michael Lind, and Margaret Washington, will address elements of the election from Jacksonian, Hamiltonian, and Tubmanian perspectives. Michael Federici is professor of political science at Mercyhurst University and department chair. One of his more recent books, The Political Philosophy of Alexander Hamilton, goes beyond the analyses of Hamilton that pit him as a monarchist, elitist, and proto-nationalist thinker and instead, looks at how Hamilton’s political philosophy was misunderstood. Federici received his Ph.D. and M.A. from The Catholic University of America in Washington, D.C., and his B.S. in economics from Elizabethtown College. Michael Lind’s most recent book, Land of Promise: An Economic History of the United States, dives into his knowledge on topics from Jackson, Hamilton, and Lincoln’s America with a view to their relevance in the current presidential election. Lind is policy director of The Economic Growth Program as well as a co-founder of New America, a think tank and civic enterprise. He became New America’s first fellow in 1999. A graduate of the University of Texas and Yale University, Lind has taught at Harvard and Johns Hopkins and has been an editor and staff writer for The New Yorker, Harper’s, The New Republic, and The National Interest. He is a columnist for Salon and writes frequently for The New York Times and The Financial Times. Margaret Washington is a professor of history at Cornell University where she specializes in African American history and culture, African American women, and Southern history, including Sojourner Truth and Harriet Tubman. She is one of the foremost authorities on the black experience. Washington’s most recent major work, Sojourner Truth’s America, unravels Sojourner Truth’s world within the broader panorama of American history, slavery, and other significant reforms in the turbulent age of Abraham Lincoln. Washington holds a B.A. from California State University, Sacramento, an M.A. from New York University, and a Ph.D. from the University of California, Davis. The speakers will address elements of the current election that reflect at least one of the following: (1) an Andrew Jacksonian dimension (e.g., populism and democracy, distrust of central government, distrust of banks or high finance, strong federal executive in practice, ethnocentrism, nativism, indigenous rights); (2) an Alexander Hamiltonian dimension (e.g., faith in banks and high finance, energetic federal executive, strong central government, cooperation between government and industry, meritocracy and distrust of popular democracy, anti-racism, anti-slavery, pro- immigration); (3) a Harriet Tubmanian dimension (e.g., gender, race, freedom, equality, basic human rights). About The Institute The Institute for Freedom & Community was established at St. Olaf College, a private liberal arts college, in 2015 to encourage free inquiry and meaningful debate of important political and social issues. The Institute programs, including coursework, Public Affairs Conversation, public affairs internships and public lectures, aim to challenge assumptions, question easy answers, and foster constructive, respectful dialogue among those with differing values and contending points of view. About St. Olaf College One of the nation’s leading liberal arts colleges, St. Olaf College offers a distinctive education grounded in academic rigor, residential learning, global engagement, and a vibrant Lutheran faith tradition. By cultivating the habits of mind and heart that enable graduates to lead lives of financial independence, professional accomplishment, personal fulfillment, and community engagement, St. Olaf College provides an uncommon educational experience that fully prepares students to make a meaningful difference in a changing world.
Christensen A.M.,George Mason University |
Ousley S.D.,Mercyhurst University |
Houck M.M.,Consolidated Forensic Laboratory
Journal of Forensic Sciences | Year: 2014
The discussion of "error" has gained momentum in forensic science in the wake of the Daubert guidelines and has intensified with the National Academy of Sciences' Report. Error has many different meanings, and too often, forensic practitioners themselves as well as the courts misunderstand scientific error and statistical error rates, often confusing them with practitioner error (or mistakes). Here, we present an overview of these concepts as they pertain to forensic science applications, discussing the difference between practitioner error (including mistakes), instrument error, statistical error, and method error. We urge forensic practitioners to ensure that potential sources of error and method limitations are understood and clearly communicated and advocate that the legal community be informed regarding the differences between interobserver errors, uncertainty, variation, and mistakes. © 2013 American Academy of Forensic Sciences.
Hefner J.T.,Central Identification Laboratory |
Ousley S.D.,Mercyhurst University
Journal of Forensic Sciences | Year: 2014
Ancestry assessments using cranial morphoscopic traits currently rely on subjective trait lists and observer experience rather than empirical support. The trait list approach, which is untested, unverified, and in many respects unrefined, is relied upon because of tradition and subjective experience. Our objective was to examine the utility of frequently cited morphoscopic traits and to explore eleven appropriate and novel methods for classifying an unknown cranium into one of several reference groups. Based on these results, artificial neural networks (aNNs), OSSA, support vector machines, and random forest models showed mean classification accuracies of at least 85%. The aNNs had the highest overall classification rate (87.8%), and random forests show the smallest difference between the highest (90.4%) and lowest (76.5%) classification accuracies. The results of this research demonstrate that morphoscopic traits can be successfully used to assess ancestry without relying only on the experience of the observer. © 2014 American Academy of Forensic Sciences.
Characterizing and controlling intrinsic biases of lambda exonuclease in nascent strand sequencing reveals phasing between nucleosomes and G-quadruplex motifs around a subset of human replication origins
Foulk M.S.,Brown University |
Foulk M.S.,Mercyhurst University |
Urban J.M.,Brown University |
Casella C.,Brown University |
And 2 more authors.
Genome Research | Year: 2015
Nascent strand sequencing (NS-seq) is used to discover DNA replication origins genome-wide, allowing identification of features for their specification. NS-seq depends on the ability of lambda exonuclease (λ-exo) to efficiently digest parental DNA while leaving RNA-primer protected nascent strands intact. We used genomics and biochemical approaches to determine if λ-exo digests all parental DNA sequences equally. We report that λ-exo does not efficiently digest G-quadruplex (G4) structures in a plasmid. Moreover, λ-exo digestion of nonreplicating genomic DNA (LexoG0) enriches GC-rich DNA and G4 motifs genome-wide. We used LexoG0 data to control for nascent strand-independent λ-exo biases in NSseq and validated this approach at the rDNA locus. The λ-exo-controlled NS-seq peaks are not GC-rich, and only 35.5% overlap with 6.8% of all G4s, suggesting that G4s are not general determinants for origin specification but may play a role for a subset. Interestingly, we observed a periodic spacing of G4 motifs and nucleosomes around the peak summits, suggesting that G4s may position nucleosomes at this subset of origins. Finally, we demonstrate that use of Na+ instead of K+ in the λ-exo digestion buffer reduced the effect of G4s on λ-exo digestion and discuss ways to increase both the sensitivity and specificity of NS-seq. © 2015 Foulk et al.
Persico L.,Mercyhurst University |
Meyer G.,University of New Mexico
Earth Surface Processes and Landforms | Year: 2013
Two centuries of human activities in the Greater Yellowstone Ecosystem (GYE) have strongly influenced beaver activity on small streams, raising questions about the suitability of the historical (Euro-American) period for establishing stream reference conditions. We used beaver-pond deposits as proxy records of beaver occupation to compare historical beaver activity to that throughout the Holocene. Forty-nine carbon-14 (14C) ages on beaver-pond deposits from Grand Teton National Park indicate that beaver activity was episodic, where multi-century periods lacking dated beaver-pond deposits have similar timing to those previously documented in Yellowstone National Park. These gaps in the sequence of dated deposits coincide with episodes of severe, prolonged drought, e.g. within the Medieval Climatic Anomaly 1000-600calyr bp, when small streams likely became ephemeral. In contrast, many beaver-pond deposits date to 500-100calyr bp, corresponding to the colder, effectively wetter Little Ice Age. Abundant historical beaver activity in the early 1900s is coincident with a climate cooler and wetter than present and more abundant willow and aspen, but also regulation of beaver trapping and the removal of wolves (the beaver's main predator), all favorable for expanded beaver populations. Reduced beaver populations after the 1920s, particularly in the northern Yellowstone winter range, are in part a response to elk overbrowsing of willow and aspen that later stemmed from wolf extirpation. Beaver populations on small streams were also impacted by low streamflows during severe droughts in the 1930s and late 1980s to present. Thus, both abundant beaver in the 1920s and reduced beaver activity at present reflect the combined influence of management practices and climate, and underscore the limitations of the early historical period for defining reference conditions. The Holocene record of beaver activity prior to Euro-American activities provides a better indication of the natural range of variability in beaver-influenced small stream systems of the GYE. © 2012 John Wiley & Sons, Ltd.
Garvin H.M.,Mercyhurst University |
Sholts S.B.,Smithsonian Institution |
Mosca L.A.,Mercyhurst University
American Journal of Physical Anthropology | Year: 2014
Sex estimation from the skull is commonly performed by physical and forensic anthropologists using a five-trait scoring system developed by Walker. Despite the popularity of this method, validation studies evaluating its accuracy across a variety of samples are lacking. Furthermore, it remains unclear what other intrinsic or extrinsic variables are related to the expression of these traits. In this study, cranial trait scores and postcranial measurements were collected from four diverse population groups (U.S. Whites, U.S. Blacks, medieval Nubians, and Arikara Native Americans) following Walker's protocols (total n = 499). Univariate and multivariate analyses were utilized to evaluate the accuracy of these traits in sex estimation, and to test for the effects of population, age, and body size on trait expressions. Results revealed significant effects of population on all trait scores. Sample-specific correct sex classification rates ranged from 74% to 94%, with an overall accuracy of 85% for the pooled sample. Classification performance varied among the traits (best for glabella and mastoid scores and worst for nuchal scores). Furthermore, correlations between traits were weak or nonsignificant, suggesting that different factors may influence individual traits. Some traits displayed correlations with age and/or postcranial size that were significant but weak, and within-population analyses did not reveal any consistent relationships between these traits across all groups. These results indicate that neither age nor body size plays a large role in trait expression, and thus does not need to be incorporated into sex estimation methods. © 2014 Wiley Periodicals, Inc.
Magoc C.J.,Mercyhurst University
Public Historian | Year: 2014
This essay attempts to counter the scarcity of efforts to address issues of natural resource extraction and environmental exploitation in public history forums. Focused on western Pennsylvania, it argues that the history of industrial development and its deleterious environmental impacts demands a regional vision that not only frames these stories within the ideological and economic context of the past, but also challenges residents and visitors to consider this history in light of the related environmental concerns of our own time. The essay explores some of the difficult issues faced by public historians and practitioners as they seek to produce public environmental histories that do not elude opportunities to link past and present in meaningful ways. © 2014 by The Regents of the University of California and the National Council on Public History.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 111.21K | Year: 2013
Supereruptions - explosive events that eject more than 1000 cubic kilometers of volcanic material - capture our imagination and compel us to consider the potential effects of one of Earths rarest yet deadliest acts. Comprehending what led to supereruptions in the past is essential to understanding and predicting similar events in places where supereruptive activity is currently possible, including the U.S. (e.g. Yellowstone), South America, Indonesia, and New Zealand. This project will investigate an exemplary exposure of 18- to 19-million-year-old volcanic and intrusive igneous rocks in the southern Black Mountains of Arizona, where the geologic record documents magmatic evolution of the Peach Spring Tuff supereruption, which is the focus of this project. Students participating in the REU will address questions that are important to both the scientific community and the public: (1) How does supereruptive magmatism compare to typical-scale magmatism (e.g. Mount St. Helens in 1980), and how are these connected? (2) What does a supervolcano look like before it erupts? (3) What are the relationships between intrusive rocks and spatially and temporally associated volcanics? (4) How and why do large magmatic systems change through time? It will also provide a platform for testing and applying integrated field and analytical methods for tracking evolution of magma systems, including optical and scanning electron microscopy, rock and mineral analysis by X-ray fluorescence and laser ablation-inductively coupled plasma mass spectrometry, GIS, and remote sensing, tools that can also be combined to address questions at other magmatic centers.
In addition to advancing the understanding of the magmatic systems that produce supervolcanoes and thereby enhancing comprehension and forecasting of future supereruptions, this project will provide a valuable introduction to research for 30 diverse undergraduates whose opportunities may be otherwise limited. It will contribute to the scientific literacy, problem solving and communication skills and the confidence of this group of students, thereby enhancing their general education, and it will attract future earth scientists to the field, providing them with a sound foundation to begin a graduate or professional career and enduring collegial relationships with peers and faculty. This project will foster new and continuing collaborations involving participating students, leaders, and researchers at other academic institutions. It will also provide valuable mentoring experience for two early-career faculty (one female) and one outstanding female PhD student, all of whom are pursuing careers emphasizing mentoring undergraduate researchers.