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• 1. [Article] Multivalent Rechargeable Batteries

  Li+ ion batteries have been the mainstay of high energy storage devices that have revolutionized the operating life time of consumer electronic devices for the past two decades. However, there is a steady ...

  Citation × Citation Citation Abstract Copy Title: Multivalent Rechargeable Batteries Author: Padigi, Sudhaprasanna Kumar Year: 2015 Li+ ion batteries have been the mainstay of high energy storage devices that have revolutionized the operating life time of consumer electronic devices for the past two decades. However, there is a steady increase in demand for energy storage devices with the ability to store more energy and deliver them at high power at low cost, without comprising safety and lifetime. Li-ion batteries have had significant challenges in increasing the amount of stored energy without affecting the overall lifetime and the ability to deliver stored energy. In order to store and deliver more energy, more lithium ions need to be inserted and extracted from a given electrode (cathode or anode). Upon inserting a large number of Li ions, the crystal lattice of the materials undergo severe mechanical distortions, leading to un-desirable structural changes. This results in underutilization of theoretical energy storage capacities of the electrodes and early failure of the batteries owing to instabilities in the electrode materials. Unlike monovalent Li+ ions, multivalent rechargeable batteries offer a potential solution to the above problems. Multivalent cations, such as Ca2+, are doubly-ionized as opposed to Li+ which is a monovalent cation. The advantages of using Ca2+ ions instead of Li+ ions are multifold. Due to the doubly-ionized nature, only half the number of Ca2+ ions need to be inserted and extracted from a given electrode to store and deliver energy from a high capacity cathode as compared to Li+ ions. This reduces the probability of lattice distortion and un-desirable structural changes, further leading to increased utilization of high theoretical energy storage capacities of the electrodes (cathode and anode). The use of Ca2+ ions also helps in delivering twice the amount of current density as compared to Li+ ions due to its doubly ionized nature. In this work, a set of eight metal hexacyanoferrate compounds were synthesized using the following metal ions: Ba2+, Mn2+, Zn2+, Co2+, Fe3+, Al3+, Sn4+, Mo5+. The resulting metal hexacyanoferrate compounds were subjected to physical characterization using scanning electron microscope (SEM) and powder x-ray diffraction (XRD), to determine physical properties such as size, morphology, unit cell symmetry and unit cell parameters. This was followed by electrochemical characterization utilizing cyclic voltammetry and galvanic cycling, to determine the specific capacity and kinetics involved in the transport of Ca2+ ions to store charge. Optical characterization of the metal hexacyanoferrates using Fourier transform infrared (FTIR) spectroscopy, allowed for the identification of metal-nitrogen stretching frequency, which was used as a measure of the strength of the metal-nitrogen bond to understand the role of the above mentioned metal ions in electron density distribution across the unit cell of the metal hexacyanoferrates. The specific capacity utilization of the metal hexacyanoferrates, when compared to the electronegativity values (Xi) of the above mentioned metal ions, the σ- parameter, and the metal-nitrogen stretching frequency (v), revealed an empirical trend suggesting that the materials (FeHCF, CaCoHCF and CaZnHCF) that possessed intermediates values for the above mentioned parameters demonstrated high capacity utilization (≥50%). Based on these empirical trends, it is hypothesized that a uniform distribution of electron density around a unit cell, as reflected by intermediate values of the electronegativity (Xi) of the above mentioned metal ions, the σ-parameter and the metal-nitrogen stretching frequency (v), results in minimal electrostatic interactions between the intercalating cation and the host unit cell lattice. This results in relatively easy diffusion of the cations, leading to high specific capacity utilization for metal hexacyanoferrate cathodes. These parameters may be used to select high efficiency cathode materials for multivalent batteries. Title: Multivalent Rechargeable Batteries Author: Padigi, Sudhaprasanna Kumar Year: 2015 Li+ ion batteries have been the mainstay of high energy storage devices that have revolutionized the operating life time of consumer electronic devices for the past two decades. However, there is a steady increase in demand for energy storage devices with the ability to store more energy and deliver them at high power at low cost, without comprising safety and lifetime. Li-ion batteries have had significant challenges in increasing the amount of stored energy without affecting the overall lifetime and the ability to deliver stored energy. In order to store and deliver more energy, more lithium ions need to be inserted and extracted from a given electrode (cathode or anode). Upon inserting a large number of Li ions, the crystal lattice of the materials undergo severe mechanical distortions, leading to un-desirable structural changes. This results in underutilization of theoretical energy storage capacities of the electrodes and early failure of the batteries owing to instabilities in the electrode materials. Unlike monovalent Li+ ions, multivalent rechargeable batteries offer a potential solution to the above problems. Multivalent cations, such as Ca2+, are doubly-ionized as opposed to Li+ which is a monovalent cation. The advantages of using Ca2+ ions instead of Li+ ions are multifold. Due to the doubly-ionized nature, only half the number of Ca2+ ions need to be inserted and extracted from a given electrode to store and deliver energy from a high capacity cathode as compared to Li+ ions. This reduces the probability of lattice distortion and un-desirable structural changes, further leading to increased utilization of high theoretical energy storage capacities of the electrodes (cathode and anode). The use of Ca2+ ions also helps in delivering twice the amount of current density as compared to Li+ ions due to its doubly ionized nature. In this work, a set of eight metal hexacyanoferrate compounds were synthesized using the following metal ions: Ba2+, Mn2+, Zn2+, Co2+, Fe3+, Al3+, Sn4+, Mo5+. The resulting metal hexacyanoferrate compounds were subjected to physical characterization using scanning electron microscope (SEM) and powder x-ray diffraction (XRD), to determine physical properties such as size, morphology, unit cell symmetry and unit cell parameters. This was followed by electrochemical characterization utilizing cyclic voltammetry and galvanic cycling, to determine the specific capacity and kinetics involved in the transport of Ca2+ ions to store charge. Optical characterization of the metal hexacyanoferrates using Fourier transform infrared (FTIR) spectroscopy, allowed for the identification of metal-nitrogen stretching frequency, which was used as a measure of the strength of the metal-nitrogen bond to understand the role of the above mentioned metal ions in electron density distribution across the unit cell of the metal hexacyanoferrates. The specific capacity utilization of the metal hexacyanoferrates, when compared to the electronegativity values (Xi) of the above mentioned metal ions, the σ- parameter, and the metal-nitrogen stretching frequency (v), revealed an empirical trend suggesting that the materials (FeHCF, CaCoHCF and CaZnHCF) that possessed intermediates values for the above mentioned parameters demonstrated high capacity utilization (≥50%). Based on these empirical trends, it is hypothesized that a uniform distribution of electron density around a unit cell, as reflected by intermediate values of the electronegativity (Xi) of the above mentioned metal ions, the σ-parameter and the metal-nitrogen stretching frequency (v), results in minimal electrostatic interactions between the intercalating cation and the host unit cell lattice. This results in relatively easy diffusion of the cations, leading to high specific capacity utilization for metal hexacyanoferrate cathodes. These parameters may be used to select high efficiency cathode materials for multivalent batteries. Close

• 2. [Article] Strontium, Lead, and Oxygen Isotopic Signatures of Mid-Miocene Silicic Volcanism in Eastern Oregon

  Widespread, mid-Miocene rhyolite volcanism of eastern Oregon that are coeval or slightly postdate flood basalts of the Columbia River Basalt Province allows for mapping crustal domains using radiogenic ...

  Citation × Citation Citation Abstract Copy Title: Strontium, Lead, and Oxygen Isotopic Signatures of Mid-Miocene Silicic Volcanism in Eastern Oregon Author: Hess, Emily Nancy Year: 2014 Widespread, mid-Miocene rhyolite volcanism of eastern Oregon that are coeval or slightly postdate flood basalts of the Columbia River Basalt Province allows for mapping crustal domains using radiogenic and stable isotopes. Rhyolites are thought to be derived in large part by partial melting of the crust and thus yield direct information on the composition of the crust. Silicic volcanism is expressed in the form of numerous domes and tuffs exposed over a wide area (~300 km in N-S dimension and ~200 km in E-W dimension) west of the presumed craton boundary, which runs parallel but mostly east of the Oregon-Idaho state border as delineated by geophysical characteristics and isotopic transitions, including the 87Sr/86Sri = 0.7060 line (MSL) and 87Sr/86Sri = 0.7040 (CSL). 87Sr/86Sri of twenty-seven silicic units are variable and some are high. Sr isotopic ratios are inconsistent with the location of the traditional MSL and CSL boundaries. A primary control on the 87Sr/86Sri isotope variations may reflect changes in the crustal make-up of Paleozoic accreted terranes of a particular area rather than arising from a westward-dipping decollement that moved cratonic lithosphere below accreted terranes in eastern Oregon. A secondary control on observed isotopic ratios may be related to the amount and composition of basalt involved in the generation of rhyolites. This could lead to higher or lower 87Sr/86Sri relative to the surrounding crust because de facto coeval mafic magmas of the Columbia River Basalt Group have a wide range of Sr isotopic signatures. While Pb isotope data is incomplete for all samples of this study, the available data indicate a significant range in Pb isotopes. Yet, data of individual regions tend to plot close to one another relative to the entire data distribution. Comparison of samples from this study in a more regional view indicates the samples generally fall within the previously defined lead isotope boundaries of the main-phase Columbia River Basalt Group lavas. [lowercase delta]¹⁸O values range from below 2 parts per thousand to above 9 parts per thousand. In addition, there is a crude trend of rhyolites having lower [lowercase delta]¹⁸O and more radiogenic ⁸⁷Sr/⁸⁶Sr[subscript i] ratios. The lowest oxygen ratios (< 2 parts per thousand) are found in rhyolites ~80 km west of the cratonic margin, potentially reflecting remelting or assimilation of hydrothermally altered crust. Low [lowercase delta]¹⁸O of selected rhyolite flows cannot be explained by remelting of Cretaceous plutons of the Idaho Batholith and appear irreconcilable with remelting of altered silicic rocks at centers of multiple, confocal caldera cycles- both processes that have been proposed to explain low [lowercase delta]¹⁸O of rhyolites of the Snake River Plain-Yellowstone area. Title: Strontium, Lead, and Oxygen Isotopic Signatures of Mid-Miocene Silicic Volcanism in Eastern Oregon Author: Hess, Emily Nancy Year: 2014 Widespread, mid-Miocene rhyolite volcanism of eastern Oregon that are coeval or slightly postdate flood basalts of the Columbia River Basalt Province allows for mapping crustal domains using radiogenic and stable isotopes. Rhyolites are thought to be derived in large part by partial melting of the crust and thus yield direct information on the composition of the crust. Silicic volcanism is expressed in the form of numerous domes and tuffs exposed over a wide area (~300 km in N-S dimension and ~200 km in E-W dimension) west of the presumed craton boundary, which runs parallel but mostly east of the Oregon-Idaho state border as delineated by geophysical characteristics and isotopic transitions, including the 87Sr/86Sri = 0.7060 line (MSL) and 87Sr/86Sri = 0.7040 (CSL). 87Sr/86Sri of twenty-seven silicic units are variable and some are high. Sr isotopic ratios are inconsistent with the location of the traditional MSL and CSL boundaries. A primary control on the 87Sr/86Sri isotope variations may reflect changes in the crustal make-up of Paleozoic accreted terranes of a particular area rather than arising from a westward-dipping decollement that moved cratonic lithosphere below accreted terranes in eastern Oregon. A secondary control on observed isotopic ratios may be related to the amount and composition of basalt involved in the generation of rhyolites. This could lead to higher or lower 87Sr/86Sri relative to the surrounding crust because de facto coeval mafic magmas of the Columbia River Basalt Group have a wide range of Sr isotopic signatures. While Pb isotope data is incomplete for all samples of this study, the available data indicate a significant range in Pb isotopes. Yet, data of individual regions tend to plot close to one another relative to the entire data distribution. Comparison of samples from this study in a more regional view indicates the samples generally fall within the previously defined lead isotope boundaries of the main-phase Columbia River Basalt Group lavas. [lowercase delta]¹⁸O values range from below 2 parts per thousand to above 9 parts per thousand. In addition, there is a crude trend of rhyolites having lower [lowercase delta]¹⁸O and more radiogenic ⁸⁷Sr/⁸⁶Sr[subscript i] ratios. The lowest oxygen ratios (< 2 parts per thousand) are found in rhyolites ~80 km west of the cratonic margin, potentially reflecting remelting or assimilation of hydrothermally altered crust. Low [lowercase delta]¹⁸O of selected rhyolite flows cannot be explained by remelting of Cretaceous plutons of the Idaho Batholith and appear irreconcilable with remelting of altered silicic rocks at centers of multiple, confocal caldera cycles- both processes that have been proposed to explain low [lowercase delta]¹⁸O of rhyolites of the Snake River Plain-Yellowstone area. Close

• 3. [Article] Participation in Technology Standards Development: A Decision Model for the Information and Communications Technology Industry

  There is a dearth of decision-support models or frameworks to aid managers in the Information and Communications Technology (ICT) industry in uniformly assessing the key factors in the decision to standardize ...

  Citation × Citation Citation Abstract Copy Title: Participation in Technology Standards Development: A Decision Model for the Information and Communications Technology Industry Author: Neshati, Ramin Year: 2014 There is a dearth of decision-support models or frameworks to aid managers in the Information and Communications Technology (ICT) industry in uniformly assessing the key factors in the decision to standardize innovative technologies. Making the proper decision is consequential and potentially fraught with risks for the firm such as competitive exposure, high expenditures with inadequate returns, restrictive inbound or outbound patent licensing obligations, and related complications. This study presents a framework to guide managers in the ICT industry in assessing the factors that inform the decision to participate in the development of technology standards. Using multi-criteria decision analysis and judgment data from panels of experts, a robust model is developed that comprehends the essential criteria and outcomes within the context of computer interconnect technologies. The resultant, generalizable model is validated against the case of the extant Universal Serial Bus (USB) interconnect standard and found to be congruent with the assessment of the experts. Scholarship on technology standards development is rich and multifaceted--spanning numerous streams of inquiry. This research contextualizes technology standardization within the economic, strategic, organizational, and legal perspectives. The resultant model demonstrates that strategic planning is regarded by the experts as the principal driver in the decision to participate in a technology standardization effort. Furthermore, the primacy of commitment and leadership within the standards-setting organization is unambiguously established through rigorous quantitative analysis. The proposed model verifies that the firm's desire to align its product roadmap to the emerging standard is the chief criterion in the decision to contribute to the standards development effort. Other criteria of high interest include the leveraging of network externalities to glean disruptive trends within the ecosystem, the exploration of opportunities to expand the total available market for the firm, and the availability and terms of IP licenses. Sensitivity analysis affirms the overall predictive strength and robustness of the model and its widespread applicability. Future research on model expansion and application to other technologies, as well as the development of uniform patent valuation methods will further enrich the knowledge base. Title: Participation in Technology Standards Development: A Decision Model for the Information and Communications Technology Industry Author: Neshati, Ramin Year: 2014 There is a dearth of decision-support models or frameworks to aid managers in the Information and Communications Technology (ICT) industry in uniformly assessing the key factors in the decision to standardize innovative technologies. Making the proper decision is consequential and potentially fraught with risks for the firm such as competitive exposure, high expenditures with inadequate returns, restrictive inbound or outbound patent licensing obligations, and related complications. This study presents a framework to guide managers in the ICT industry in assessing the factors that inform the decision to participate in the development of technology standards. Using multi-criteria decision analysis and judgment data from panels of experts, a robust model is developed that comprehends the essential criteria and outcomes within the context of computer interconnect technologies. The resultant, generalizable model is validated against the case of the extant Universal Serial Bus (USB) interconnect standard and found to be congruent with the assessment of the experts. Scholarship on technology standards development is rich and multifaceted--spanning numerous streams of inquiry. This research contextualizes technology standardization within the economic, strategic, organizational, and legal perspectives. The resultant model demonstrates that strategic planning is regarded by the experts as the principal driver in the decision to participate in a technology standardization effort. Furthermore, the primacy of commitment and leadership within the standards-setting organization is unambiguously established through rigorous quantitative analysis. The proposed model verifies that the firm's desire to align its product roadmap to the emerging standard is the chief criterion in the decision to contribute to the standards development effort. Other criteria of high interest include the leveraging of network externalities to glean disruptive trends within the ecosystem, the exploration of opportunities to expand the total available market for the firm, and the availability and terms of IP licenses. Sensitivity analysis affirms the overall predictive strength and robustness of the model and its widespread applicability. Future research on model expansion and application to other technologies, as well as the development of uniform patent valuation methods will further enrich the knowledge base. Close

• 4. [Article] Exploring Pedestrian Responsive Traffic Signal Timing Strategies in Urban Areas

  The role of walking in the development of healthy, livable communities is being increasingly recognized. In urban areas, intersections represent locations where different modes converge, and are often ...

  Citation × Citation Citation Abstract Copy Title: Exploring Pedestrian Responsive Traffic Signal Timing Strategies in Urban Areas Author: Kothuri, Sirisha Murthy Year: 2014 The role of walking in the development of healthy, livable communities is being increasingly recognized. In urban areas, intersections represent locations where different modes converge, and are often viewed as deterrents to walking. This is due to the unwarranted and often unnecessary delays imposed by signal timing policies for pedestrians and increased potential for conflicts. Traditional signal timing design prioritizes vehicles over pedestrians leading to undesirable consequences such as large delays and risky pedestrian behaviors. Pedestrians are accommodated in a manner that is designed to cause least interruption to the flow of motor vehicles. This lack of pedestrian accommodation at signalized intersections is the focus of this dissertation. Understanding pedestrian attitudes and perceptions is important because it offers insights into actual crossing behavior at signalized intersections. An intercept survey of 367 crossing pedestrians was undertaken at four signalized intersections in Portland, Oregon, and binary logistic regression models were constructed to quantify the impacts of demographics, trip characteristics and type of infrastructure on pedestrian perceptions and attitudes regarding delay, crossing time and motivators for crossing decisions. Safety was found to have a larger effect than compliance on the decision to cross the street. Pedestrians at recall intersections expressed higher satisfaction with delay than at actuated intersections. Novel methods to measure pedestrian delay using 2070 signal controllers and Voyage software were developed. These methods have been adopted by the City of Portland to record actuation trends and delays at various intersections. In the absence of demand data, pedestrian push button actuations can be considered as a proxy for crossing demand. The micro-simulation software VISSIM was used to analyze delays resulting from varying pedestrian and vehicle volumes on a network of three intersections in Portland, Oregon. From a pedestrian perspective, free operation was found to be always beneficial due to lower pedestrian delays. However, from a system wide perspective, free operation was found to be beneficial only under low-medium traffic conditions from an overall delay reduction viewpoint, while coordinated operation showed benefits under heavy traffic conditions, irrespective of the volume of pedestrians. Control strategies were developed to identify the best mode of signal controller operation that produced the lowest overall average delay per user. A procedure to identify the optimal control strategy based on user inputs (major street volume to capacity ratios and rate of pedestrian phase serviced for the minor street) was developed. The procedure was applied to a network of three intersections in east Portland, OR and the findings were verified. This research offers significant contributions in the field of pedestrian research. The findings related to attitudes and perceptions of crossing pedestrians offer greater insights into pedestrian crossing behavior and add to the body of existing literature. The methods developed to obtain pedestrian actuations and delay data from signal controllers represent an easy and cost-effective way to characterize pedestrian service at intersections. The results pertaining to signal timing strategies represent an important step towards incorporating pedestrian needs at intersections and demonstrate how control strategies employed to benefit pedestrians could benefit the entire system. Title: Exploring Pedestrian Responsive Traffic Signal Timing Strategies in Urban Areas Author: Kothuri, Sirisha Murthy Year: 2014 The role of walking in the development of healthy, livable communities is being increasingly recognized. In urban areas, intersections represent locations where different modes converge, and are often viewed as deterrents to walking. This is due to the unwarranted and often unnecessary delays imposed by signal timing policies for pedestrians and increased potential for conflicts. Traditional signal timing design prioritizes vehicles over pedestrians leading to undesirable consequences such as large delays and risky pedestrian behaviors. Pedestrians are accommodated in a manner that is designed to cause least interruption to the flow of motor vehicles. This lack of pedestrian accommodation at signalized intersections is the focus of this dissertation. Understanding pedestrian attitudes and perceptions is important because it offers insights into actual crossing behavior at signalized intersections. An intercept survey of 367 crossing pedestrians was undertaken at four signalized intersections in Portland, Oregon, and binary logistic regression models were constructed to quantify the impacts of demographics, trip characteristics and type of infrastructure on pedestrian perceptions and attitudes regarding delay, crossing time and motivators for crossing decisions. Safety was found to have a larger effect than compliance on the decision to cross the street. Pedestrians at recall intersections expressed higher satisfaction with delay than at actuated intersections. Novel methods to measure pedestrian delay using 2070 signal controllers and Voyage software were developed. These methods have been adopted by the City of Portland to record actuation trends and delays at various intersections. In the absence of demand data, pedestrian push button actuations can be considered as a proxy for crossing demand. The micro-simulation software VISSIM was used to analyze delays resulting from varying pedestrian and vehicle volumes on a network of three intersections in Portland, Oregon. From a pedestrian perspective, free operation was found to be always beneficial due to lower pedestrian delays. However, from a system wide perspective, free operation was found to be beneficial only under low-medium traffic conditions from an overall delay reduction viewpoint, while coordinated operation showed benefits under heavy traffic conditions, irrespective of the volume of pedestrians. Control strategies were developed to identify the best mode of signal controller operation that produced the lowest overall average delay per user. A procedure to identify the optimal control strategy based on user inputs (major street volume to capacity ratios and rate of pedestrian phase serviced for the minor street) was developed. The procedure was applied to a network of three intersections in east Portland, OR and the findings were verified. This research offers significant contributions in the field of pedestrian research. The findings related to attitudes and perceptions of crossing pedestrians offer greater insights into pedestrian crossing behavior and add to the body of existing literature. The methods developed to obtain pedestrian actuations and delay data from signal controllers represent an easy and cost-effective way to characterize pedestrian service at intersections. The results pertaining to signal timing strategies represent an important step towards incorporating pedestrian needs at intersections and demonstrate how control strategies employed to benefit pedestrians could benefit the entire system. Close

• 5. [Article] Prospective Elementary Mathematics Teacher Content Knowledge: What Do We Know, What Do We Not Know, and Where Do We Go?

  The authors reviewed 112 research studies from 1978 to 2012 on prospective elementary teachers' content knowledge in five content areas: whole numbers and operations, fractions, decimals, geometry and ...

  Citation × Citation Citation Abstract Copy Title: Prospective Elementary Mathematics Teacher Content Knowledge: What Do We Know, What Do We Not Know, and Where Do We Go? Author: Thanheiser, Eva, Browning, Christine, Edson, Alden, Lo, Jane-Jane, Whitacre, Ian, Olanoff, Dana, Morton, Crystal Year: 2014 The authors reviewed 112 research studies from 1978 to 2012 on prospective elementary teachers' content knowledge in five content areas: whole numbers and operations, fractions, decimals, geometry and measurement, and algebra. Looking across these studies, this final paper identifies the trends and common themes in terms of the counts and types of studies and commonalities among findings. Analyses of the counts show that the number of articles published each year focusing on prospective teacher (PT) content knowledge is increasing. Most articles across the content areas show that PTs tend to rely on procedures rather than concepts. However, the focus of most articles is identifying PTs' misconceptions rather than understanding PTs' conceptions and the development thereof. Both the limitations of the reviews and the directions for future research studies are elaborated. Title: Prospective Elementary Mathematics Teacher Content Knowledge: What Do We Know, What Do We Not Know, and Where Do We Go? Author: Thanheiser, Eva, Browning, Christine, Edson, Alden, Lo, Jane-Jane, Whitacre, Ian, Olanoff, Dana, Morton, Crystal Year: 2014 The authors reviewed 112 research studies from 1978 to 2012 on prospective elementary teachers' content knowledge in five content areas: whole numbers and operations, fractions, decimals, geometry and measurement, and algebra. Looking across these studies, this final paper identifies the trends and common themes in terms of the counts and types of studies and commonalities among findings. Analyses of the counts show that the number of articles published each year focusing on prospective teacher (PT) content knowledge is increasing. Most articles across the content areas show that PTs tend to rely on procedures rather than concepts. However, the focus of most articles is identifying PTs' misconceptions rather than understanding PTs' conceptions and the development thereof. Both the limitations of the reviews and the directions for future research studies are elaborated. Close

• 6. [Article] Origins of Late- Pleistocene Coastal Dune Sheets, Magdalena and Guerrero Negro, from Continental Shelf Low-stand Supply (70-20 ka), under Conditions of Southeast Littoral- and Eolian-Sand Transport, in Baja California Sur, Mexico

  Shallow morpho-stratigraphic sections (n = 11) in each of two large coastal dune sheets including the Magdalena (7000 km2) and Guerrero Negro (8000 km2) dune sheets, from the Pacific Ocean side of Baja ...

  Citation × Citation Citation Abstract Copy Title: Origins of Late- Pleistocene Coastal Dune Sheets, Magdalena and Guerrero Negro, from Continental Shelf Low-stand Supply (70-20 ka), under Conditions of Southeast Littoral- and Eolian-Sand Transport, in Baja California Sur, Mexico Author: Peterson, Curt D., Murillo-Jiminez, Janette, Stock, Errol, Price, David M., Hostetler, Steve W., Percy, David Year: 2017 Shallow morpho-stratigraphic sections (n = 11) in each of two large coastal dune sheets including the Magdalena (7000 km2) and Guerrero Negro (8000 km2) dune sheets, from the Pacific Ocean side of Baja California Sur, Mexico, have been analyzed for dune deposit age. The shallow morpho-stratigraphic sections (∼2-10 m depth) include 11 new TL and 14C ages, and paleosol chronosequences, that differentiate cemented late Pleistocene dune deposits (20.7 ± 2.1 to 99.8 ± 9.4 ka) from uncemented Holocene dune deposits (0.7 ± 0.05 to at least 3.2 ± 0.3 ka). Large linear dune ridges (5-10 m in height) in the dune sheet interiors trend southeast and are generally of late Pleistocene age (∼70-20 ka). The late Pleistocene dune deposits reflect eolian transport of marine sand across the emerged continental shelf (30-50 km southeast distance) from low-stand paleo-shorelines (-100 ± 25 m elevation), which were locally oriented nearly orthogonal to modeled deep-water wave directions (∼300° TN). During the Holocene marine transgression, onshore and alongshore wave transport delivered remobilized shelf-sand deposits to the nearshore areas of the large dune sheets, building extensive barrier islands and sand spits. Submerged back-barrier lagoons generally precluded marine sand supply to dune sheet interiors in middle to late Holocene time, though exceptions occur along some ocean and lagoon shorelines. Reactivation of the late Pleistocene dune deposits in the dune sheet interiors lead to generally thin (1-3 m thickness), but widespread, covers of Holocene dune deposits (0.41 ± 0.05 to 10.5 ± 1.6 ka). Mechanical drilling will be required to penetrate indurated subsoil caliche layers to reach basal Pleistocene dune deposits. Title: Origins of Late- Pleistocene Coastal Dune Sheets, Magdalena and Guerrero Negro, from Continental Shelf Low-stand Supply (70-20 ka), under Conditions of Southeast Littoral- and Eolian-Sand Transport, in Baja California Sur, Mexico Author: Peterson, Curt D., Murillo-Jiminez, Janette, Stock, Errol, Price, David M., Hostetler, Steve W., Percy, David Year: 2017 Shallow morpho-stratigraphic sections (n = 11) in each of two large coastal dune sheets including the Magdalena (7000 km2) and Guerrero Negro (8000 km2) dune sheets, from the Pacific Ocean side of Baja California Sur, Mexico, have been analyzed for dune deposit age. The shallow morpho-stratigraphic sections (∼2-10 m depth) include 11 new TL and 14C ages, and paleosol chronosequences, that differentiate cemented late Pleistocene dune deposits (20.7 ± 2.1 to 99.8 ± 9.4 ka) from uncemented Holocene dune deposits (0.7 ± 0.05 to at least 3.2 ± 0.3 ka). Large linear dune ridges (5-10 m in height) in the dune sheet interiors trend southeast and are generally of late Pleistocene age (∼70-20 ka). The late Pleistocene dune deposits reflect eolian transport of marine sand across the emerged continental shelf (30-50 km southeast distance) from low-stand paleo-shorelines (-100 ± 25 m elevation), which were locally oriented nearly orthogonal to modeled deep-water wave directions (∼300° TN). During the Holocene marine transgression, onshore and alongshore wave transport delivered remobilized shelf-sand deposits to the nearshore areas of the large dune sheets, building extensive barrier islands and sand spits. Submerged back-barrier lagoons generally precluded marine sand supply to dune sheet interiors in middle to late Holocene time, though exceptions occur along some ocean and lagoon shorelines. Reactivation of the late Pleistocene dune deposits in the dune sheet interiors lead to generally thin (1-3 m thickness), but widespread, covers of Holocene dune deposits (0.41 ± 0.05 to 10.5 ± 1.6 ka). Mechanical drilling will be required to penetrate indurated subsoil caliche layers to reach basal Pleistocene dune deposits. Close

• 7. [Article] Disequilibrium of Fire-prone Forests Sets the Stage for a Rapid Decline in Conifer Dominance during the 21st Century

  As trees are long-lived organisms, the impacts of climate change on forest communities may not be apparent on the time scale of years to decades. While lagged responses to environmental change are common ...

  Citation × Citation Citation Abstract Copy Title: Disequilibrium of Fire-prone Forests Sets the Stage for a Rapid Decline in Conifer Dominance during the 21st Century Author: Serra-Diaz, Josep M., Maxwell, Charles, Lucash, Melissa S., Scheller, Robert M., Laflower, Danelle M., Miller, Adam D., Tepley, Alan J., Epstein, Howard E., Anderson-Teixeira, Kristina J., Thompson, Jonathan R. Year: 2017 As trees are long-lived organisms, the impacts of climate change on forest communities may not be apparent on the time scale of years to decades. While lagged responses to environmental change are common in forested systems, potential for abrupt transitions under climate change may occur in environments where alternative vegetation states are influenced by disturbances, such as fire. The Klamath mountains (northern California and southwest Oregon, USA) are currently dominated by carbon rich and hyper-diverse temperate conifer forests, but climate change could disrupt the mechanisms promoting forest stability– regeneration and fire tolerance— via shifts in the fire regime in conjunction with lower fitness of conifers under a hotter climate. Understanding how this landscape will respond to near-term climate change (before 2100) is critical for predicting potential climate change feedbacks and to developing sound forest conservation and management plans. Using a landscape simulation model, we estimate that 1/3 of the Klamath could transition from conifer forest to shrub/hardwood chaparral, triggered by an enhanced fire activity coupled with lower post-fire conifer establishment. Such shifts were more prevalent under higher climate change forcing (RCP 8.5) but were also simulated under the climate of 1950-2000, reflecting the joint influences of early warming trends and historical forest legacies. Our results demonstrate that there is a large potential for loss of conifer forest dominance—and associated carbon stocks and biodiversity-- in the Klamath before the end of the century, and that some losses would likely occur even without the influence of climate change. Thus, in the Klamath and other forested landscapes subject to similar feedback dynamics, major ecosystem shifts should be expected when climate change disrupts key stabilizing feedbacks that maintain the dominance of long-lived, slowly regenerating trees. Title: Disequilibrium of Fire-prone Forests Sets the Stage for a Rapid Decline in Conifer Dominance during the 21st Century Author: Serra-Diaz, Josep M., Maxwell, Charles, Lucash, Melissa S., Scheller, Robert M., Laflower, Danelle M., Miller, Adam D., Tepley, Alan J., Epstein, Howard E., Anderson-Teixeira, Kristina J., Thompson, Jonathan R. Year: 2017 As trees are long-lived organisms, the impacts of climate change on forest communities may not be apparent on the time scale of years to decades. While lagged responses to environmental change are common in forested systems, potential for abrupt transitions under climate change may occur in environments where alternative vegetation states are influenced by disturbances, such as fire. The Klamath mountains (northern California and southwest Oregon, USA) are currently dominated by carbon rich and hyper-diverse temperate conifer forests, but climate change could disrupt the mechanisms promoting forest stability– regeneration and fire tolerance— via shifts in the fire regime in conjunction with lower fitness of conifers under a hotter climate. Understanding how this landscape will respond to near-term climate change (before 2100) is critical for predicting potential climate change feedbacks and to developing sound forest conservation and management plans. Using a landscape simulation model, we estimate that 1/3 of the Klamath could transition from conifer forest to shrub/hardwood chaparral, triggered by an enhanced fire activity coupled with lower post-fire conifer establishment. Such shifts were more prevalent under higher climate change forcing (RCP 8.5) but were also simulated under the climate of 1950-2000, reflecting the joint influences of early warming trends and historical forest legacies. Our results demonstrate that there is a large potential for loss of conifer forest dominance—and associated carbon stocks and biodiversity-- in the Klamath before the end of the century, and that some losses would likely occur even without the influence of climate change. Thus, in the Klamath and other forested landscapes subject to similar feedback dynamics, major ecosystem shifts should be expected when climate change disrupts key stabilizing feedbacks that maintain the dominance of long-lived, slowly regenerating trees. Close

• 8. [Article] Data Mining of Bridge Concrete Deck Parameters in the National Bridge Inventory by Two-Step Cluster Analysis

  Data mining is a discovery procedure to explore and visualize useful but less-than-obvious information or patterns in large collections of data. Given the amount and varying parameter types in a large ...

  Citation × Citation Citation Abstract Copy Title: Data Mining of Bridge Concrete Deck Parameters in the National Bridge Inventory by Two-Step Cluster Analysis Author: Radovic, Matija, Ghonima, Omar, Schumacher, Thomas Year: 2017 Data mining is a discovery procedure to explore and visualize useful but less-than-obvious information or patterns in large collections of data. Given the amount and varying parameter types in a large data set such as that of the National Bridge Inventory (NBI), using traditional clustering techniques for discovery is impractical. As a consequence, the authors have applied a novel data discovery tool, called Two-step cluster analysis, to visualize associations between concrete bridge deck design parameters and bridge deck condition ratings. Two-step cluster analysis is a powerful knowledge discovery tool that can handle categorical and interval data simultaneously and is capable of reducing dimensions for large data sets. The analysis, of a total of 9,809 concrete highway bridge decks in the Northeast climatic region, found that bridges with cast-in-place decks that have a bituminous wearing surface, a preformed fabric membrane, and epoxy-coated reinforcement protection are strongly associated with the high condition ratings for bridge decks regardless of the average daily truck traffic (ADTT). Conversely, results show that bridges with cast-in-place bridge decks that have a bituminous wearing surface but have neither a deck membrane nor deck reinforcement protection are strongly associated with low condition ratings for bridge decks regardless of the ADTT. It was concluded that Two-step cluster analysis is a useful tool for bridge owners and agencies to visualize general trends in their concrete bridge deck condition data and to support them in their decision-making processes to effectively allocate limited funds for maintenance, repair, and design of bridge decks. Title: Data Mining of Bridge Concrete Deck Parameters in the National Bridge Inventory by Two-Step Cluster Analysis Author: Radovic, Matija, Ghonima, Omar, Schumacher, Thomas Year: 2017 Data mining is a discovery procedure to explore and visualize useful but less-than-obvious information or patterns in large collections of data. Given the amount and varying parameter types in a large data set such as that of the National Bridge Inventory (NBI), using traditional clustering techniques for discovery is impractical. As a consequence, the authors have applied a novel data discovery tool, called Two-step cluster analysis, to visualize associations between concrete bridge deck design parameters and bridge deck condition ratings. Two-step cluster analysis is a powerful knowledge discovery tool that can handle categorical and interval data simultaneously and is capable of reducing dimensions for large data sets. The analysis, of a total of 9,809 concrete highway bridge decks in the Northeast climatic region, found that bridges with cast-in-place decks that have a bituminous wearing surface, a preformed fabric membrane, and epoxy-coated reinforcement protection are strongly associated with the high condition ratings for bridge decks regardless of the average daily truck traffic (ADTT). Conversely, results show that bridges with cast-in-place bridge decks that have a bituminous wearing surface but have neither a deck membrane nor deck reinforcement protection are strongly associated with low condition ratings for bridge decks regardless of the ADTT. It was concluded that Two-step cluster analysis is a useful tool for bridge owners and agencies to visualize general trends in their concrete bridge deck condition data and to support them in their decision-making processes to effectively allocate limited funds for maintenance, repair, and design of bridge decks. Close

• 9. [Article] Using Popular Education With Health Promotion Students in the USA

  Recent publications have called for new approaches to training the next generation of health promotion professionals, for whom effective practice depends on understanding how systemic inequities are created ...

  Citation × Citation Citation Abstract Copy Title: Using Popular Education With Health Promotion Students in the USA Author: Wiggins, Noelle, Pérez, Amara Year: 2017 Recent publications have called for new approaches to training the next generation of health promotion professionals, for whom effective practice depends on understanding how systemic inequities are created and function and how they can be dismantled. These approaches gain particular urgency in the context of recent trends toward commodification of knowledge at both the secondary and post-secondary levels. Popular education, a liberatory pedagogy, has been used in social movements around the world for decades. In a health promotion context, its use has been associated with increased empowerment and improved health. To explore the potential of popular education (PE) for helping health promotion students develop a systemic analysis of power and privilege and the concrete skills needed to address health and social inequities, we conducted a case study in the context of a community organizing class in a Master's in Public Health curriculum. Analysis of mixed methods data collected from students suggested that PE, with its focus on concrete practices and interactions, is a valid alternative to conventional pedagogy and a useful complement to liberatory pedagogies more common in university classrooms. Application of PE in higher education will require overcoming barriers, including student resistance and institutional pressures that discourage its use. Title: Using Popular Education With Health Promotion Students in the USA Author: Wiggins, Noelle, Pérez, Amara Year: 2017 Recent publications have called for new approaches to training the next generation of health promotion professionals, for whom effective practice depends on understanding how systemic inequities are created and function and how they can be dismantled. These approaches gain particular urgency in the context of recent trends toward commodification of knowledge at both the secondary and post-secondary levels. Popular education, a liberatory pedagogy, has been used in social movements around the world for decades. In a health promotion context, its use has been associated with increased empowerment and improved health. To explore the potential of popular education (PE) for helping health promotion students develop a systemic analysis of power and privilege and the concrete skills needed to address health and social inequities, we conducted a case study in the context of a community organizing class in a Master's in Public Health curriculum. Analysis of mixed methods data collected from students suggested that PE, with its focus on concrete practices and interactions, is a valid alternative to conventional pedagogy and a useful complement to liberatory pedagogies more common in university classrooms. Application of PE in higher education will require overcoming barriers, including student resistance and institutional pressures that discourage its use. Close

• 10. [Article] Archival Water-Level Measurements: Recovering Historical Data to Help Design for the Future

  Improving methods of assessing risk and designing structures to withstand extreme events and changing sea levels is a vital component of strategies for reducing risk to coastal resources and assets. An ...

  Citation × Citation Citation Abstract Copy Title: Archival Water-Level Measurements: Recovering Historical Data to Help Design for the Future Author: Talke, Stefan A., Jay, David A. Year: 2017 Improving methods of assessing risk and designing structures to withstand extreme events and changing sea levels is a vital component of strategies for reducing risk to coastal resources and assets. An obvious approach to improving the statistical robustness of risk assessments is to increase the number, time span, and quality of available water-level data sets, and to assess trends and non-stationarity. In this report we discuss efforts to recover, digitize, and analyze hundreds of station-years of lost-and-forgotten tide data and other water-level measurements that extend back to the early 19th century. To date, more than 6,500 station-years of previously lost or forgotten tide data have been identified, of which more than 1,600 station-years have been recovered and more than 550 station-years digitized. An additional 500+ years of once-a-day river-stage measurements in tidal rivers have been recovered and digitized. Approximately 300,000 documents have been recovered. In this report we also demonstrate how data recovery can help engineers better characterize their water-level environment and understand long-term trends, resulting in better risk assessment and ultimately more robust design of new infrastructure and adaptation of existing infrastructure. Long records help improve hazard estimates and can help characterize whether statistics are nonstationarity over climate-relevant time scales. Further, long and more complete records exhibit more natural variability and can be used to validate numerical simulations of historical storms (e.g., the 1893 New York hurricane). Historical tide data can help inform how tidal datums such as High Water and Low Water have changed, can be used to hindcast historical river flow, and provide a much richer view of long-term trends in local sea level. Used with numerical models, historical data help explain how anthropogenic activities have changed tide range and river slope, with the largest effects often observed far inland from the coast. Moreover, numerical models combined with tide data can be used to assess whether local engineering or other long-term changes have influenced storm surge risk. In conclusion, improved assessment of the past can help us better plan for the future. Title: Archival Water-Level Measurements: Recovering Historical Data to Help Design for the Future Author: Talke, Stefan A., Jay, David A. Year: 2017 Improving methods of assessing risk and designing structures to withstand extreme events and changing sea levels is a vital component of strategies for reducing risk to coastal resources and assets. An obvious approach to improving the statistical robustness of risk assessments is to increase the number, time span, and quality of available water-level data sets, and to assess trends and non-stationarity. In this report we discuss efforts to recover, digitize, and analyze hundreds of station-years of lost-and-forgotten tide data and other water-level measurements that extend back to the early 19th century. To date, more than 6,500 station-years of previously lost or forgotten tide data have been identified, of which more than 1,600 station-years have been recovered and more than 550 station-years digitized. An additional 500+ years of once-a-day river-stage measurements in tidal rivers have been recovered and digitized. Approximately 300,000 documents have been recovered. In this report we also demonstrate how data recovery can help engineers better characterize their water-level environment and understand long-term trends, resulting in better risk assessment and ultimately more robust design of new infrastructure and adaptation of existing infrastructure. Long records help improve hazard estimates and can help characterize whether statistics are nonstationarity over climate-relevant time scales. Further, long and more complete records exhibit more natural variability and can be used to validate numerical simulations of historical storms (e.g., the 1893 New York hurricane). Historical tide data can help inform how tidal datums such as High Water and Low Water have changed, can be used to hindcast historical river flow, and provide a much richer view of long-term trends in local sea level. Used with numerical models, historical data help explain how anthropogenic activities have changed tide range and river slope, with the largest effects often observed far inland from the coast. Moreover, numerical models combined with tide data can be used to assess whether local engineering or other long-term changes have influenced storm surge risk. In conclusion, improved assessment of the past can help us better plan for the future. Close