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University of Montana

2015

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Articles 1 - 30 of 71

Full-Text Articles in Physical Sciences and Mathematics

Coarse Bedload Routing And Dispersion Through Tributary Confluences, Kurt Imhoff, Andrew C. Wilcox Dec 2015

Coarse Bedload Routing And Dispersion Through Tributary Confluences, Kurt Imhoff, Andrew C. Wilcox

Geosciences Faculty Publications

Sediment routing fundamentally influences channel morphology and propagation of disturbances. However, the transport and storage of bedload particles in headwater channel confluences, which may be significant nodes of the channel network in terms of sediment routing, morphology, and habitat, is poorly understood. To characterize routing processes through confluences of headwater channels, we investigate how sediment routing patterns through headwater confluences compare to those described in low-gradient gravel bed river systems, and how confluences affect the dispersive behavior of coarse bedload particles compared to non-confluence reaches. We address these questions with a field tracer experiment using passive-integrated transponder and radio-frequency identification …

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Which Came First, People Or Pollution? Assessing The Disparate Siting And Post-Siting Demographic Change Hypotheses Of Environmental Injustice, Paul Mohai, Robin Saha Nov 2015

Which Came First, People Or Pollution? Assessing The Disparate Siting And Post-Siting Demographic Change Hypotheses Of Environmental Injustice, Paul Mohai, Robin Saha

Environmental Studies Faculty Publications

Although a large body of quantitative environmental justice research exists, only a handful of studies have examined the processes by which racial and socioeconomic disparities in the location of polluting industrial facilities can occur. These studies have had mixed results, we contend, principally because of methodological differences, that is, the use of the unit-hazard coincidence method as compared to distance-based methods. This study is the first national-level environmental justice study to conduct longitudinal analyses using distance-based methods. Our purposes are to: (1) determine whether disparate siting, post-siting demographic change, or a combination of the two created present-day disparities; (2) test …

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In Situ Measurements And Modeling Of Reactive Trace Gases In A Small Biomass Burning Plume, M. Muller, B. Anderson, A. Beyersdorf, J. H. Crawford, G. Diskin, P. Eichler, A. Fried, F. N. Keutsch, T. Mikoviny, K. L. Thornhill, J. G. Walega, A. J. Weinheimer, M. Yang, Robert Yokelson, A. Wisthaler Nov 2015

In Situ Measurements And Modeling Of Reactive Trace Gases In A Small Biomass Burning Plume, M. Muller, B. Anderson, A. Beyersdorf, J. H. Crawford, G. Diskin, P. Eichler, A. Fried, F. N. Keutsch, T. Mikoviny, K. L. Thornhill, J. G. Walega, A. J. Weinheimer, M. Yang, Robert Yokelson, A. Wisthaler

Chemistry and Biochemistry Faculty Publications

An instrumented NASA P-3B aircraft was used for airborne sampling of trace gases in a plume that had emanated from a small forest understory fire in Georgia, USA. The plume was sampled at its origin for deriving emission factors and followed ~ 13.6 km downwind for observing chemical changes during the first hour of atmospheric aging. The P-3B payload included a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS), which measured non-methane organic gases (NMOGs) at unprecidented spatio-temporal resolution (10m/0.1 s). Quantitative emission data are reported for CO2, CO, NO, NO2, HONO, NH3 and 16 NMOGs (formaldehyde, methanol, …

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Flow And Scour Constrainst On Uprooting Of Pioneer Woody Seedlings, Sharon Bywater-Reyes, Andrew C. Wilcox, John C. Stella, Anne Lightbody Nov 2015

Flow And Scour Constrainst On Uprooting Of Pioneer Woody Seedlings, Sharon Bywater-Reyes, Andrew C. Wilcox, John C. Stella, Anne Lightbody

Geosciences Faculty Publications

Scour and uprooting during flood events is a major disturbance agent that affects plant mortality rates and subsequent vegetation composition and density, setting the trajectory of physical-biological interactions in rivers. During flood events, riparian plants may be uprooted if they are subjected to hydraulic drag forces greater than their resisting force. We measured the resisting force of woody seedlings established on river bars with in situ lateral pull tests that simulated flood flows with and without substrate scour. We quantified the influence of seedling sizes, species (Populus and Tamarix), water-table depth, and scour depth on resisting force. Seedling …

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Variations In Solar Wind Fractionation As Seen By Ace/Swics And The Implications For Genesis Mission Results, P. Pilleri, Daniel B. Reisenfeld, T. H. Zurbuchen, S. T. Lepri, P. Shearer, J. A. Gilbert, R. Von Steiger, R. C. Wiens Oct 2015

Variations In Solar Wind Fractionation As Seen By Ace/Swics And The Implications For Genesis Mission Results, P. Pilleri, Daniel B. Reisenfeld, T. H. Zurbuchen, S. T. Lepri, P. Shearer, J. A. Gilbert, R. Von Steiger, R. C. Wiens

Physics and Astronomy Faculty Publications

We use Advanced Composition Explorer (ACE)/Solar Wind Ion Composition Spectrometer (SWICS) elemental composition data to compare the variations in solar wind (SW) fractionation as measured by SWICS during the last solar maximum (1999-2001), the solar minimum (2006-2009), and the period in which the Genesis spacecraft was collecting SW (late 2001-early 2004). We differentiate our analysis in terms in SW regimes (i.e., originating from interstream or coronal hole flows, or coronal mass ejecta). Abundances are normalized to the low-first ionization potential (low-FIP) ion magnesium to uncover correlations that are not apparent when normalizing to high-FIP ions. We find that relative …

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Research And Development Of A Smart Module Integrated Converter For The Future Of Renewable Energy, Phong Tran Oct 2015

Research And Development Of A Smart Module Integrated Converter For The Future Of Renewable Energy, Phong Tran

University Grant Program Reports

This research focused on developing of a Smart Module Integrated Converter for grid-connected solar photovoltaic (PV) system. This technology enhances the commercial micro-inverters with novel network-supported, grid-adapted functionalities. The micro-inverter utilizes open source and reference design from Microchip to keep design and production at low cost.

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Is Atmospheric Phosphorus Pollution Altering Global Alpine Lake Stoichiometry?, Janice Brahney, Natalie Mahowald, Daniel S. Ward, Ashley P. Ballantyne, Jason C. Neff Sep 2015

Is Atmospheric Phosphorus Pollution Altering Global Alpine Lake Stoichiometry?, Janice Brahney, Natalie Mahowald, Daniel S. Ward, Ashley P. Ballantyne, Jason C. Neff

Ecosystem and Conservation Sciences Faculty Publications

Anthropogenic activities have significantly altered atmospheric chemistry and changed the global mobility of key macro-nutrients. Here we show that contemporary global patterns in nitrogen (N) and phosphorus (P) emissions drive large hemispheric variation in precipitation chemistry. These global patterns of nutrient emission and deposition (N:P) are in turn closely reflected in the water chemistry of naturally oligotrophic lake (r2 = 0.81, p < 0.0001). Observed increases in anthropogenic N deposition play a role in nutrient concentrations (r2 = 0.02, p < 0.05); however, atmospheric deposition of P appears to be major contributor to this pattern (r2 = 0.65, p < 0.0001). Atmospheric simulations indicate a global increase in P deposition by 1.4 times the pre-industrial rate largely due to increased dust and biomass burning emissions. Although changes in the mass flux of global P deposition are smaller than for N, the impacts on primary productivity may be greater because, on average, one unit of increased P deposition has 16 times the influence of one unit of N deposition. These stoichiometric considerations, combined with the evidence presented here, suggest that increases in P deposition may be a major driver of alpine Lake trophic status, particularly in the Southern Hemisphere. These results underscore the need for the broader scientific community to consider the impact of atmospheric phosphorus deposition on the water quality of naturally oligotrophic lakes.

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Dynamics Of Thermally Induced Ice Streams Simulated With A Higher-Order Flow Model, Douglas Brinkerhoff, Jesse Johnson Sep 2015

Dynamics Of Thermally Induced Ice Streams Simulated With A Higher-Order Flow Model, Douglas Brinkerhoff, Jesse Johnson

Computer Science Faculty Publications

We use a new discretization technique to solve the higher-order thermomechanically coupled equations of glacier evolution. We find that under radially symmetric continuum equations, small perturbations in symmetry due to the discretization are sufficient to produce the initiation of non-symmetric thermomechanical instabilities which we interpret as ice streams, in good agreement with previous studies which have indicated a similar instability. We find that the inclusion of membrane stresses regularizes the size of predicted streams, eliminating the ill-posedness evident in previous investigations of ice stream generation through thermomechanical instability. Ice streams exhibit strongly irregular periodicity which is influenced by neighboring ice …

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Problems In The Theory Of Extremal Graphs And Hypergraphs, Cory T. Palmer Sep 2015

Problems In The Theory Of Extremal Graphs And Hypergraphs, Cory T. Palmer

University Grant Program Reports

Objective: Investigate the tree packing conjecture from graph theory and extremal numbers for hypergraphs.

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The Science And Practice Of River Restoration, Ellen E. Wohl, Stuart N. Lane, Andrew C. Wilcox Aug 2015

The Science And Practice Of River Restoration, Ellen E. Wohl, Stuart N. Lane, Andrew C. Wilcox

Geosciences Faculty Publications

River restoration is one of the most prominent areas of applied water-resources science. From an initial focus on enhancing fish habitat or river appearance, primarily through structural modification of channel form, restoration has expanded to incorporate a wide variety of management activities designed to enhance river process and form. Restoration is conducted on headwater streams, large lowland rivers, and entire river networks in urban, agricultural, and less intensively human-altered environments. We critically examine how contemporary practitioners approach river restoration and challenges for implementing restoration, which include clearly identified objectives, holistic understanding of rivers as ecosystems, and the role of restoration …

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Biomass Burning Emissions And Potential Air Quality Impacts Of Volatile Organic Compounds And Other Trace Gases From Temperate Fuels Common In The United States, J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. De Gouw, I. R. Burling, Robert Yokelson Aug 2015

Biomass Burning Emissions And Potential Air Quality Impacts Of Volatile Organic Compounds And Other Trace Gases From Temperate Fuels Common In The United States, J. B. Gilman, B. M. Lerner, W. C. Kuster, P. D. Goldan, C. Warneke, P. R. Veres, J. M. Roberts, J. A. De Gouw, I. R. Burling, Robert Yokelson

Chemistry and Biochemistry Faculty Publications

A comprehensive suite of instruments was used to quantify the emissions of over 200 organic gases, including methane and volatile organic compounds (VOCs), and 9 inorganic gases from 56 laboratory burns of 18 different biomass fuel types common in the southeastern, southwestern, or northern United States. A gas chromatograph-mass spectrometer (GC-MS) provided extensive chemical detail of discrete air samples collected during a laboratory burn and was complemented by real-time measurements of organic and inorganic species via an open-path Fourier transform infrared spectrometer (OP-FTIR) and 3 different chemical ionization-mass spectrometers. These measurements were conducted in February 2009 at the U.S. Department …

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Temperature Distribution And Thermal Anomalies Along A Flowline Of The Greenland Ice Sheet, Joel A. Harrington, Neil F. Humphrey, Joel T. Harper Aug 2015

Temperature Distribution And Thermal Anomalies Along A Flowline Of The Greenland Ice Sheet, Joel A. Harrington, Neil F. Humphrey, Joel T. Harper

Geosciences Faculty Publications

Englacial and basal temperature data for the Greenland ice sheet (GrIS) are sparse and mostly limited to deep interior sites and ice streams, providing an incomplete representation of the thermal state of ice within the ablation zone. Here we present 11 temperature profiles at five sites along a 34km east-west transect of West Greenland. These profiles depict ice temperatures along a flowline and local temperature variations between closely spaced boreholes. A temperate basal layer is present in all profiles, increasing in thickness in the flow direction, where it expands from about 3% of ice height furthest inland to 100% at …

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Investigating The Links Between Ozone And Organic Aerosol Chemistry In A Biomass Burning Plume From A Prescribed Fire In California Chaparral, M. J. Alvarado, C. R. Lonsdale, Robert Yokelson, Sheryl Kashi Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. Mcmeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, C. E. Wold Jun 2015

Investigating The Links Between Ozone And Organic Aerosol Chemistry In A Biomass Burning Plume From A Prescribed Fire In California Chaparral, M. J. Alvarado, C. R. Lonsdale, Robert Yokelson, Sheryl Kashi Akagi, H. Coe, J. S. Craven, E. V. Fischer, G. R. Mcmeeking, J. H. Seinfeld, T. Soni, J. W. Taylor, D. R. Weise, C. E. Wold

Chemistry and Biochemistry Faculty Publications

Within minutes after emission, complex photochemistry in biomass burning smoke plumes can cause large changes in the concentrations of ozone (O3) and organic aerosol (OA). Being able to understand and simulate this rapid chemical evolution under a wide variety of conditions is a critical part of forecasting the impact of these fires on air quality, atmospheric composition, and climate. Here we use version 2.1 of the Aerosol Simulation Program (ASP) to simulate the evolution of O3 and secondary organic aerosol (SOA) within a young biomass burning smoke plume from the Williams prescribed fire in chaparral, which was sampled over …

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Developing Strategic And Mathematical Thinking Via Game Play: Programming To Investigate A Risky Strategy For Quarto, Peter Rowlett Jun 2015

Developing Strategic And Mathematical Thinking Via Game Play: Programming To Investigate A Risky Strategy For Quarto, Peter Rowlett

The Mathematics Enthusiast

The Maths Arcade is an extracurricular club for undergraduate students to play and analyse strategy board games, aimed at building a mathematical community of staff and students as well as improving strategic and mathematical thinking. This educational initiative, used at several universities in the U.K., will be described. Quarto is an impartial game played at the Maths Arcade, in that there is one set of common pieces used by both players, and one where stalemates are a common outcome. While some students play without apparent direction until a winning opportunity appears, others adopt a more risky strategy of building the …

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Editorial: The Economics Of Risk, Bharath Sriraman Jun 2015

Editorial: The Economics Of Risk, Bharath Sriraman

The Mathematics Enthusiast

No abstract provided.

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Probability, Justice, And The Risk Of Wrongful Conviction, Jeffrey S. Rosenthal Jun 2015

Probability, Justice, And The Risk Of Wrongful Conviction, Jeffrey S. Rosenthal

The Mathematics Enthusiast

We consider the issue of standards of proof in legal decisions from the point of view of probability. We compare ``balance of probabilities'' and ``beyond a reasonable doubt'' to the statistical use of p-values. We point out various fallacies which sometimes arise in legal reasoning. And we provide several examples of legal cases which involved probabilities, including some in which incorrect decisions were made and defendants were wrongfully convicted.

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Worth The Risk? Modeling Irrational Gambling Behavior, Matt Lane Jun 2015

Worth The Risk? Modeling Irrational Gambling Behavior, Matt Lane

The Mathematics Enthusiast

In math class, expected value is often used when deciding whether or not a game is worth playing. A common refrain is that games with negative expected value should be avoided. However, nearly all games of chance have a negative expected value, and a simple expected value analysis fails to explain why these games are so popular. In this article, we consider three psychological factors leading to irrational gambling behavior – the illusion of control, hypersensitivity to reward, and beginner’s luck – and explore how these factors affect an otherwise purely rational model of gambling behavior.

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Understanding Risk Through Board Games, Joshua T. Hertel Jun 2015

Understanding Risk Through Board Games, Joshua T. Hertel

The Mathematics Enthusiast

In this article, I describe a potential avenue for investigating individual’s understanding of and reactions to risk using the medium of board games. I first discuss some challenges that researchers face in studying risk situations. Connecting to the existing probabilistic reasoning literature, I then present a rationale for using board games to model these situations. Following this, I draw upon intuition and dual-process theory to outline an integrated theoretical perspective for such investigations. The article concludes with two vignettes demonstrating how this perspective might be used to analyze thinking about risk in a board game setting.

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Risks Worth Taking? Social Risks And The Mathematics Teacher, Ami Mamolo, Laura Elizabeth Pinto Jun 2015

Risks Worth Taking? Social Risks And The Mathematics Teacher, Ami Mamolo, Laura Elizabeth Pinto

The Mathematics Enthusiast

In this article, we explore notions of risk as perceived or experienced by individuals involved in mathematical education. We present this exploration in the form of vignettes, each illustrating a form of risk: a parent’s reaction to classroom “propaganda”; a teacher trying to do justice by her students; a teacher confronted by his administration; and a college professor who believes university policy to be unjust. Each vignette sheds light on areas in which teacher education may offer additional support in fostering the mathematical knowledge, pedagogical sensitivity, and social awareness required to foster, what are in our view, much needed risks …

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Risky Research Business: Mathematics Education Research On The Margins, Erika C. Bullock Jun 2015

Risky Research Business: Mathematics Education Research On The Margins, Erika C. Bullock

The Mathematics Enthusiast

Although we would like to believe that decisions about what research to conduct and how to conduct it are based solely on researcher interest and societal need, the reality is that external political and disciplinary factors do play a role. Scientifically based research (SBR) is one example of external political pressures that shape researcher choice both directly and indirectly. Additionally, disciplines like mathematics education operate under hidden curricula that have the potential to marginalize particular research foci. The purpose of this paper is to consider the implications of such a narrow focus on a young mathematics education researcher’s choices about …

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Good Models And Good Representations Are A Support For Learners’ Risk Assessment, Laura Martignon, Sebastian Kuntze Jun 2015

Good Models And Good Representations Are A Support For Learners’ Risk Assessment, Laura Martignon, Sebastian Kuntze

The Mathematics Enthusiast

When learners have to make sense of risky situations, they can use mathematical models and representations which facilitate successful risk assessment. Based on theoretical considerations on the benefits of specific models and specific representations in such contexts, we present empirical findings of a study which examined whether students use such models and representations in their risk assessment. We conclude that the availability of adequate models to learners may help them gain transparency when facing risks and thus foster their decision-making.

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Tme Volume 12, Numbers 1, 2, And 3 Jun 2015

Tme Volume 12, Numbers 1, 2, And 3

The Mathematics Enthusiast

No abstract provided.

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Risk—A Fundamental Condition Of Doing Mathematics, Wolff-Michael Roth, Jean-François Maheux Jun 2015

Risk—A Fundamental Condition Of Doing Mathematics, Wolff-Michael Roth, Jean-François Maheux

The Mathematics Enthusiast

The theme of this special issue is risk. But risk is not a common topic of investigation in mathematics education, lest it be an occasional interest in “at risk” students, generally defined as those who likely will fail at school. In this study, we are not interested in this rather limited use of the risk concept. Instead, we show that risk not only is a condition of human life generally, but also a necessity for teaching and learning mathematics. To show this, we develop the concept of risk with materials from a second-grade mathematics unit on geometry. Implications are drawn …

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Students’ Language Repertoires For Prediction, David Wagner, Joseph Dicks, Paula Kristmanson Jun 2015

Students’ Language Repertoires For Prediction, David Wagner, Joseph Dicks, Paula Kristmanson

The Mathematics Enthusiast

Communication about prediction is complex in a number of ways. First, language is by nature recursive — language is an indicator of meaning as well as a force that shapes meaning. Second, the same language used to communicate prediction in uncertain environments is used for other purposes. In this article, we describe how the recursive nature of language impacted the choices we made in a cross-sectional longitudinal study aimed at gaining insight into children’s language repertoires relating to conjecture. We then explore some Grade 6 students’ communication about prediction to develop insight into their meaning and meaning-making with prediction language. …

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Promoting Risk Taking In Mathematics Classrooms: The Importance Of Creating A Safe Learning Environment, Sashi Sharma Jun 2015

Promoting Risk Taking In Mathematics Classrooms: The Importance Of Creating A Safe Learning Environment, Sashi Sharma

The Mathematics Enthusiast

Students beliefs and attitudes towards risk taking can impact on their mathematics learning and performance. However, at present, risk is not established in the field of mathematics education. The challenge for mathematics teachers in developing their students’ risk taking dispositions is to choose appropriate activities and tools that match this concept and the learning needs of the students. This paper describes some research-based ideas for promoting risk taking behaviours in a mathematics classroom. It presents interactional pedagogical strategies from a design collaborative research conducted at one secondary school. As part of the learning activities, students critically evaluated statistical investigations undertaken …

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Calculated Risks: The Teacher As Big Data Producer And Risk Analyst, Nat Banting Jun 2015

Calculated Risks: The Teacher As Big Data Producer And Risk Analyst, Nat Banting

The Mathematics Enthusiast

Teachers’ work is often subjected to data analysis from outside sources in the forms of standardized examinations and media critique. This article uses the literature of risk analysis to play with two important analogies for teachers with regards to the emerging big data culture and the risk decisions therein. The complex context of the classroom facilitates the exploration of teacher as big data producer, while the multi-faceted nature of risk decisions provide the groundwork for the exploration of teacher as risk analyst. Illustrative classroom episodes portray examples of real and virtual risk faced by teachers, and a third category—curricular risk—is …

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A Conversation With Herbert Tate: Mathematics Educator And Builder, Christian Genest Jun 2015

A Conversation With Herbert Tate: Mathematics Educator And Builder, Christian Genest

The Mathematics Enthusiast

Herbert Tate was a Professor of Mathematics at McGill University (Montréal, Canada) from 1921 to 1964. As the author of four textbooks, and in his capacity as Chairman of the Department of Mathematics from 1948 to 1960, he played a key role in structuring the institution’s research and study programs in mathematics during an important period of growth. McGill’s current position as a hub of mathematical research owes much to him. In this interview given shortly after his retirement, Herbert Tate describes his career and shares some of his views about mathematics and related topics. Beyond its archival value, this …

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Risk As An Explanatory Factor For Researchers’ Inferential Interpretations, Rink Hoekstra Jun 2015

Risk As An Explanatory Factor For Researchers’ Inferential Interpretations, Rink Hoekstra

The Mathematics Enthusiast

Logical reasoning is crucial in science, but we know that this is not something that humans are innately good at. It becomes even harder to reason logically about data when there is uncertainty, because there is always a chance of being wrong. Dealing with uncertainty is inevitable, for example, in situations in which the evaluation of sample outcomes with respect to some population is required. Inferential statistics is a structured way of reasoning rationally about such data. One could therefore expect that using well-known statistical techniques protects its users against misinterpretations regarding uncertainty. Unfortunately, this does not seem to be …

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A Cognitive Framework For Normative Reasoning Under Uncertainty, And Reasoning About Risk, And Implications For Educational Practice, Sylvia Kuzmak Jun 2015

A Cognitive Framework For Normative Reasoning Under Uncertainty, And Reasoning About Risk, And Implications For Educational Practice, Sylvia Kuzmak

The Mathematics Enthusiast

Clarifying what is normative or appropriate reasoning under various circumstances provides a valuable reference for guiding what should be taught, and, in contrast, what should not be. This paper proposes a cognitive framework for viewing normative reasoning and behavior under uncertainty, including the applying of knowledge of probability and statistics in real world situations; and identifies implications for educational practice. Factors relevant to normative reasoning under uncertainty that are addressed within the framework include: risk of misapplying statistics knowledge, involvement of mathematical and non-mathematical reasoning, knowledge of real world domains and situation/application detail, and existence of expert consensus. The cognitive …

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Teaching Risk In School, Andreas Eichler, Markus Vogel Jun 2015

Teaching Risk In School, Andreas Eichler, Markus Vogel

The Mathematics Enthusiast

Although risk is an important topic for society it is seldom addressed when teaching statistics and probability. In this paper we refer to this discrepancy identifying three obstacles for teaching risk in school regarding the mathematical and the situational aspect of risk. Based on two educational constructs, i.e. probability literacy and modelling, we discuss existing approaches for teaching risk in school and propose two strategies for promoting risk as a valuable issue for students based again on the distinction of the mathematical and situational aspect of risk.

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