Physical Sciences and Mathematics Commons^™

Ontology Supported Knowledge Discovery In The Field Of Human Performance And Cognition, Christopher Thomas, Pablo N. Mendes, Delroy H. Cameron, Amit P. Sheth, Krishnaprasad Thirunarayan, Cartic Ramakrishnan

Kno.e.sis Publications

No abstract provided.

Synchronicity: Just-In-Time Discovery Of Lost Web Pages, Martin Klein, Michael L. Nelson

Computer Science Presentations

PDF of a powerpoint presentation from the National Digital Information Infrastructure and Preservation Program (NDIIPP) Partners Meeting, Washington D.C., June 24-25, 2009. Also available on Slideshare.

Final Project, Shuangge Ma

Shuangge Ma

No abstract provided.

Lecture 4, Shuangge Ma

Shuangge Ma

No abstract provided.

Lecture 4, Shuangge Ma

Shuangge Ma

No abstract provided.

Computer Intensive Methods Lecture 13, Shuangge Ma

Shuangge Ma

No abstract provided.

Seed Release In Lodgepole Pine Forests After Mountain Pine Beetle Outbreak, Francios Teste, Vic J. Lieffers, Simon M. Landhausser

North American Forest Ecology Workshop

Serotinous lodgepole pine (Pinus contorta var. latifolia) usually regenerates after fire or harvesting provided conditions that are warm enough to open the cones. There are concerns that large-scale stand mortality due to mountain pine beetle (MPB) outbreak could greatly reduce natural regeneration of lodgepole pine because the closed cones are held in place in the tree canopy without any seed release. We selected 15 stands (five gray-attacked, five red-attacked, and five green) in the Sub-Boreal Spruce biogeoclimatic zone of British Columbia to determine loss of canopy seed via breakage of twig-bearing cones and cone opening (i.e., loss of serotiny) throughout …

Potential Effects Of Climate Change On Mixed Severity Fire Regimes, Jessica Halofsky, Dave L. Peterson

North American Forest Ecology Workshop

The frequency, severity, and extent of wildfire are strongly related to climate, and increasing temperatures with climate change will likely lead to changes in fire regimes in many types of ecosystems. Increased spring and summer temperatures with climate change will result in relatively early snowmelt, lower summer soil and fuel moisture, and longer fire seasons in the West. These conditions will lead to increased fire frequency and extent. Higher temperatures may also interact with vegetation and fuel characteristics to increase fire intensity and severity. Mixed severity fire regimes may be uniquely influenced by these climate-induced changes in the frequency, extent, …

Assessment Of Prescribed Burning Effects In Paludified Black Spruce Forests In Ontario’S Clay Belt Region, Sebastien Renard, Sylvie Gauthier, Nicole Fenton, Yves Bergeron, David Pare

North American Forest Ecology Workshop

Paludification, the accumulation of poorly decomposed organic matter principally originating from Sphagnum, transforms black spruce forests to forested peatlands in the prolonged absence of fire. High-severity wildfires reverse this process by burning the organic matter layer and thus restart forest succession; in contrast low severity wildfires remove only the tree layer and do not reduce paludification. On the Ontario Clay Belt, a physiogeographic region prone to paludification due to its cold climate and poor drainage, current forest harvest practices (Careful Logging Around Advanced Growth; CLAAG) mimic low severity fires by removing trees but lacking forest floor and soil disturbances caused …

An Integrated Study Investigating Masticated Fuel Treatments In The Rocky Mountains, Robert Keane, Helen Y. Smith

North American Forest Ecology Workshop

Many coniferous forests in the western US once supported frequent, low intensity fires, but due to a century of fire exclusion and other factors, severe wildfires have now become common. With the goal of lowering fire intensities and severities, one possible fuel treatment that is currently gaining favor in with many land managers is mastication which breaks, shreds, or grinds canopy (seedlings, saplings and pole trees) and surface fuel (fine and coarse woody material) into smaller sizes and deposits the treated fuel on the ground. However, very little is known concerning the effects of this treatment on the resulting fire …

A Post-Fire Index For Describing Mixed Severity Outcomes After Wildfire, Theresa Jain, Russel T. Graham, David S. Pilliod, Leigh Lentile

North American Forest Ecology Workshop

Kimmins (1997) argues that “words” and their correct usage are important and that the “careless use of language often causes confusion and misunderstanding and is a factor in many conflicts.” The public often lacks the technical knowledge to understand and interpret the use of inconsistent terminology and each discipline within resource science and management has developed their own definitions and application of specific terms. The fire community is no different. The only consistent component in the fire literature is the interchangeable use of the terms fire intensity, fire severity, and burn severity. Moreover, within each of these definitions, the terms …

Mechanical Mastication Showed Fewer Negative Above-And Belowground Impacts Than Slash Pile Burning, Suzanne Neal, Carolyn H. Sieg, Catherine A. Gehring, Matthew A. Bowker

North American Forest Ecology Workshop

Management designed to reduce wildfire risk must consider both above- and belowground factors in order to promote native plant growth and reduce soil erosion. This goal is challenging because current methods, such as tree thinning and burning the resulting slash, can create soil disturbances that favor exotic plants. We compared mechanical mastication to slash pile burning (both 6-months and 2.5-years post treatment) and untreated controls in pinyon-juniper (Pinus edulis-Juniperus osteosperma) woodland and measured soil properties, arbuscular mycorrhizal fungi (AMF) and understory plant composition. Our results showed slash pile burns had severely degraded soil properties, low plant and AMF abundance and …

A Spatio-Temporal Approach For Estimating Chronic Effects Of Air Pollution, Sonja Greven, Francesca Dominici, Scott L. Zeger

Johns Hopkins University, Dept. of Biostatistics Working Papers

Estimating the health risks associated with air pollution exposure is of great importance in public health. In air pollution epidemiology, two study designs have been used mainly. Time series studies estimate acute risk associated with short-term exposure. They compare day-to-day variation of pollution concentrations and mortality rates, and have been criticized for potential confounding by time-varying covariates. Cohort studies estimate chronic effects associated with long-term exposure. They compare long-term average pollution concentrations and time-to-death across cities, and have been criticized for potential confounding by individual risk factors or city-level characteristics.

We propose a new study design and a statistical model, …

Spatial Cluster Detection For Repeatedly Measured Outcomes While Accounting For Residential History, Andrea J. Cook, Diane Gold, Yi Li

Harvard University Biostatistics Working Paper Series

No abstract provided.

Marginalized Frailty Models For Multivariate Survival Data, Megan Othus, Yi Li

Harvard University Biostatistics Working Paper Series

No abstract provided.

Spatial Cluster Detection For Weighted Outcomes Using Cumulative Geographic Residuals, Andrea J. Cook, Yi Li, David Arterburn, Ram C. Tiwari

Harvard University Biostatistics Working Paper Series

No abstract provided.

Π+ Photoproduction On The Proton For Photon Energies From 0.725 To 2.875 Gev, M. Dugger, Gerard P. Gilfoyle, Et. Al.

Physics Faculty Publications

Differential cross sections for the reaction γp → nπ⁺ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID andMAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the …

Implementing The Information Technology Information Library (Itil) Framework, Lawrence Wade Lowder

Regis University Student Publications (comprehensive collection)

This project proposes the implementation of the Information Technology Infrastructure Library (ITIL) framework for a mid-sized Real Estate Investment Trust (REIT) specializing in commercial warehouses. Due to rapid growth, lack of process and lack of business visibility, the Information Technology (IT) department struggles to provide highly reliable business systems that meet the requirements for the business. The gap in business relationships results in a negative image for the IT department and causes situations where individual business groups contract directly with outsourced IT providers. After developing the IT solution, the business group contacts the internal IT department for involvement with the …

Sum Rules And Universality In Electron-Modulated Acoustic Phonon Interaction In A Free-Standing Semiconductor Plate, Shigeyasu Uno, Darryl H. Yong, Nobuya Mori

All HMC Faculty Publications and Research

Analysis of acoustic phonons modulated due to the surfaces of a free-standing semiconductor plate and their deformation-potential interaction with electrons are presented. The form factor for electron-modulated acoustic phonon interaction is formulated and analyzed in detail. The form factor at zero in-plane phonon wave vector satisfies sum rules regardless of electron wave function. The form factor is larger than that calculated using bulk phonons, leading to a higher scattering rate and lower electron mobility. When properly normalized, the form factors lie on a universal curve regardless of plate thickness and material.

Final Project (Description), Shuangge Ma

Shuangge Ma

No abstract provided.

Final Project (Data), Shuangge Ma

Shuangge Ma

No abstract provided.

Lecture 3, Shuangge Ma

Shuangge Ma

No abstract provided.

The Influence Of Mastication On Soils And Fuels In Moist And Dry Forests Of The Northern Rocky Mountains, Theresa Jain, Russel T. Graham

North American Forest Ecology Workshop

We evaluated the applicability of mastication as a fuel treatment alternative within Northern Rocky Mountain moist and dry forests to treat post-harvest activity slash (moist forest) and standing trees (dry forest). On the moist forest site, we compared four different slash treatments, mastication, machine grapple piling, lop and scatter, and a control within a wildland urban interface setting to determine the effects of these treatments on soil nutrition, forest floor depth, and woody debris distributions. We randomly assigned the slash treatments and controls to 12 one-acre plots. Nitrogen, soil carbon, and magnesium concentrations within the soil components were not significantly …

Aspen Mortality In The Intermountain West: What Forest Inventory And Analysis Plots Tell Us, Fred Baker, John D. Shaw

North American Forest Ecology Workshop

Reports of a long-term decline in area dominated by aspen forests, coupled with increased mortality attributed to long term drought, have lead to concerns of increased mortality in aspen forests. We examined data collected by USDA Forest Service Inventory and Analysis (FIA) to quantify aspen mortality. Most aspen stands in the Intermountain West are older than 80 years, a recommended rotation age for the best sites. Plot mortality rate was not related to site index or stand age. Many stands, however, have stem density greater than one would expect for self-thinning stands. At a given latitude, aspen plots with mortality …

Ecosystem Recovery Following A Mountain Pine Beetle Outbreak In Northern British Columbia: A Case Of Shifting Values, Craig Delong, Bennita Kaytor, Bruce J. Rogers

North American Forest Ecology Workshop

The massive Mountain Pine Beetle (MPB) outbreak in northern British Columbia created a unique opportunity to examine ecosystem change over time in response to this disturbance. Prior to this outbreak, the dominant disturbance agents were wildfire and harvesting. A key question is how timber and habitat value will change over time in response to this disturbance and how this might be impacted by extensive clearcut salvage harvest. We have established 48 permanent sample plots in MPB impacted stands. Changes in stand structure, vegetation and functional wildlife habitat along with tree mortality and growth are being monitored. There has been almost …

Surface Fuel Loadings In Mulching Treatments In Colorado Coniferous Forests, Mike Battaglia, Chuck Rhoades, Monique E. Rocca, Michael G. Ryan

North American Forest Ecology Workshop

Recent large-scale, severe wildfires in the western United States have prompted extensive fuel treatment programs to reduce potential wildfire size and severity. Often, unmerchantable material is mechanically masticated because removing the material is cost-prohibitive. Mastication treatments involve shredding, chopping, or chipping small trees and/or shrubs into small chunks and leaving the material on site. While it is obvious that mechanical treatments will increase surface fuel loads, few studies have addressed how treatments alter fuel particle size and quantity. We examined how mastication treatments alter the distribution of woody material size by comparing paired masticated and untreated sites in lodgepole pine …

Regeneration Dynamics In Mountain Pine Beetle-Disturbed Forests: Lessons From The Current And The 1978-82 Flathead Epidemics, Dave Coates

North American Forest Ecology Workshop

There are two dominant mechanisms for development of a new tree layer and subsequent canopy recruitment after major canopy mortality events. First, regeneration may develop from a pulse of new post-disturbance recruitment. Alternatively, regeneration can be from the existing seedling bank that survived the canopy mortality event. The timing and extent of post-disturbance recruitment from seed and the relative importance of the existing seedling bank is poorly understood in MPB-disturbed forests. The recruitment of post-MPB seedlings is a function of seed-source availability, seedbed substrate, overstory structure, and time since MPB attack. In the northern interior, post-MPB recruitment was sparse in …

Patterns Of Structural Response To Simulated Partial Harvesting Of Boreal Mixedwood Stands, Mark Vanderwel, John P. Caspersen, Jay R. Malcolm

North American Forest Ecology Workshop

Partial harvesting has been proposed as an approach for maintaining late-successional structure within managed boreal mixedwood stands. Although little long-term data is available to evaluate its effects in this stand type, recent advances in individual tree-based stand modeling provide an opportunity to simulate post-harvest stand development following different retention harvests. Using the stand dynamics model SORTIE-ND, we examined 40-year patterns of structural change in response to different intensities (30%, 50%, and 70% removal) and spatial patterns (uniform, small patch, large patch) of harvesting in aspen-dominated mixedwood stands. We assessed structural dynamics through a suite of variables representing the distribution of …

Stand Density In South Florida Tropical Forests: Implications For The Function And Management Of Everglades Tree Islands, M. Ross, P. L. Ruiz, J. P. Sah, L. Lopez, N. Colbert

North American Forest Ecology Workshop

Within the continental US, the broadleaved forests of south Florida are exceptional in the abundance and diversity of tree species of tropical origin. Dry tropical forests are regionally most extensive in the upper Florida Keys, but are also represented on the mainland as fragments on limestone rocklands, and as “tree islands” embedded in the Everglades marsh. The exposed Everglades tree islands have a history of human use reaching back thousands of years, and are subject to frequent disturbance from tropical storms and hurricanes. They are sensitive to the hydrology of the surrounding marsh, which can lead to gradual changes in …

Long-Term Effects Of Alternative Group Selection Harvesting Designs On Stand Production, C. Halpin, C. G. Lorimer, J. J. Hanson, B. Palik

North American Forest Ecology Workshop

Interest in group selection harvesting has increased in recent years because of limitations associated with both clearcutting and single-tree selection. Field data have suggested that group selection openings can have higher production rates than single-tree gaps, but whether this translates into higher production rates at the stand level is not clear. We used CANOPY, a crown-based northern hardwoods model calibrated with data from uneven-aged and even-aged stands, to simulate sustainable harvest volumes of a number of different group selection approaches over 300 years, and also compared results with those from single-tree selection and clearcutting. When a combination of single-tree and …