Quantifying the influence of past wildfires on the severity and size of subsequent wildfires

Wildfire is arguably one of the most important and widespread natural disturbance agents in western U.S. forests. It has a substantial impact on ecosystem structure and function by influencing soils, nutrients, carbon budgets, wildlife habitat, and vegetation. Wildfires also influence fuel amount, type, and structure, potentially influencing the severity and size of subsequent wildfires through site- and landscape-level feedback mechanisms. Until relatively recently, the ability to quantitatively evaluate how these feedback mechanisms operate has not been feasible because of data limitations (i.e. there has not been enough wildfire). However, due to increased fire activity over the last ~25 years, there are a number of examples of wildfires “interacting” with subsequent fires, where a wildfire either burns within the perimeter of a previously burned area (i.e. it reburns) or burns up to (but not in to) a previously burned area. This recent surge in fire activity, along with increased availability of remotely sensed data, now makes it possible to evaluate how wildfires influence subsequent fire severity and size over large landscapes. Some studies have suggested that extreme weather conditions may decrease the strength of the feedback mechanisms associated with interacting fires, and consequently, evaluating the influence of weather on such relationships is increasingly important, especially given that climate change is expected to result in more extreme weather events. This dissertation is composed of three chapters. The first chapter quantifies how previous wildfire influences the severity of subsequent fires. In my second chapter, I develop and evaluate several approaches to estimate day-of-burning for each point within a fire perimeter using coarse-resolution MODIS fire detection data. Knowing the day-ofburning is essential in order to evaluate the influence of observed weather (e.g., from a nearby weather station) on observed fire-related effects, such as smoke production or the previously mentioned feedback mechanisms of fire. My third chapter evaluates the ability of wildfire to act as a fuel break by limiting the extent (i.e. size) of subsequent fire. Using the methods from Chapter Two to estimate day-of-burning, I was also able to evaluate the influence of weather in weakening the strength of this feedback

Wisent: Robust Downstream Communication and Storage for Computational RFIDs

Computational RFID (CRFID) devices are emerging platforms that can enable perennial computation and sensing by eliminating the need for batteries. Although much research has been devoted to improving upstream (CRFID to RFID reader) communication rates, the opposite direction has so far been neglected, presumably due to the difficulty of guaranteeing fast and error-free transfer amidst frequent power interruptions of CRFID. With growing interest in the market where CRFIDs are forever-embedded in many structures, it is necessary for this void to be filled. Therefore, we propose Wisent-a robust downstream communication protocol for CRFIDs that operates on top of the legacy UHF RFID communication protocol: EPC C1G2. The novelty of Wisent is its ability to adaptively change the frame length sent by the reader, based on the length throttling mechanism, to minimize the transfer times at varying channel conditions. We present an implementation of Wisent for the WISP 5 and an off-the-shelf RFID reader. Our experiments show that Wisent allows transfer up to 16 times faster than a baseline, non-adaptive shortest frame case, i.e. single word length, at sub-meter distance. As a case study, we show how Wisent enables wireless CRFID reprogramming, demonstrating the world's first wirelessly reprogrammable (software defined) CRFID.Comment: Accepted for Publication to IEEE INFOCOM 201

The Effects of the Food Stamp Program on Energy Balance and Obesity

The Effects of the Food Stamp Program on Energy Balance and ObesityFood Stamp Program (FSP), Supplemental Nutrition Assistance Program (SNAP), obesity, body mass index (BMI), nutrition assistance, Food Consumption/Nutrition/Food Safety, Q18, H53, I12, I18, I38,

Quantifying Obesity in Economic Research: How Misleading is the Body Mass Index?

Replaced with revised version of paper 07/19/10.Obesity, percent body fat (PBF), body mass index (BMI), economic costs, measurement error, Health Economics and Policy, Research and Development/Tech Change/Emerging Technologies, C52, I10,

The Effects of the Food Stamp Program on Energy Balance and Obesity

The Food Stamp Program (FSP) administered by the U.S. Department of Agriculture (USDA) is the cornerstone of the U.S. federal income and food safety net policy. The FSP has subsidized the food budget for millions of American households for over forty years, spending more than $60 billion per year in recent times. Prior research has demonstrated that women who participate in the FSP are more likely to be overweight or obese than eligible non-participants. This finding raises the concern that the additional income provided by FSP benefits induces participants to eat significantly more calories and gain weight, contributing to the U.S. obesity epidemic. Previous studies of the FSP have yielded mixed results. In this study we develop new conceptual and empirical models linking FSP participation, calorie consumption, physical activity, and weight gain, while controlling for genetic variation, weight history, and other physiological characteristics of individuals. The models enable us to test whether participants gained more weight, ate more calories, or engaged less in physical activity; or if previously omitted variables and individual health characteristics explain the higher prevalence of obesity among female FSP participants. We find a positive relationship between FSP participation and weight gain for a small subset of women. We do not find convincing evidence for the hypothesis that FSP participation causes obesity by increasing caloric consumption, decreasing physical activity, or some combination of the two. Our findings suggest that a positive association between FSP and weight exists, but we find no evidence of a direct causal link from one to the other. The association between weight and FSP likely results from confounding factors that make individuals more likely both to gain weight and to participate in the FSP.Food Stamp Program (FSP), Supplemental Nutrition Assistance Program (SNAP), obesity, body mass index (BMI), nutrition assistance, Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Health Economics and Policy, Q18, H53, I12, I18, I38,

Increasing phylogenetic resolution at low taxonomic levels using massively parallel sequencing of chloroplast genomes

<p>Abstract</p> <p>Background</p> <p>Molecular evolutionary studies share the common goal of elucidating historical relationships, and the common challenge of adequately sampling taxa and characters. Particularly at low taxonomic levels, recent divergence, rapid radiations, and conservative genome evolution yield limited sequence variation, and dense taxon sampling is often desirable. Recent advances in massively parallel sequencing make it possible to rapidly obtain large amounts of sequence data, and multiplexing makes extensive sampling of megabase sequences feasible. Is it possible to efficiently apply massively parallel sequencing to increase phylogenetic resolution at low taxonomic levels?</p> <p>Results</p> <p>We reconstruct the infrageneric phylogeny of <it>Pinus </it>from 37 nearly-complete chloroplast genomes (average 109 kilobases each of an approximately 120 kilobase genome) generated using multiplexed massively parallel sequencing. 30/33 ingroup nodes resolved with ≥ 95% bootstrap support; this is a substantial improvement relative to prior studies, and shows massively parallel sequencing-based strategies can produce sufficient high quality sequence to reach support levels originally proposed for the phylogenetic bootstrap. Resampling simulations show that at least the entire plastome is necessary to fully resolve <it>Pinus</it>, particularly in rapidly radiating clades. Meta-analysis of 99 published infrageneric phylogenies shows that whole plastome analysis should provide similar gains across a range of plant genera. A disproportionate amount of phylogenetic information resides in two loci (<it>ycf</it>1, <it>ycf</it>2), highlighting their unusual evolutionary properties.</p> <p>Conclusion</p> <p>Plastome sequencing is now an efficient option for increasing phylogenetic resolution at lower taxonomic levels in plant phylogenetic and population genetic analyses. With continuing improvements in sequencing capacity, the strategies herein should revolutionize efforts requiring dense taxon and character sampling, such as phylogeographic analyses and species-level DNA barcoding.</p

Exploration of Backscatter Methods for Wireless Avionics

This report describes and characterizes the low-power Jeeva Passive Radio systems, including Wanscatter (passive Chirp Spread Spectrum) and Passive Wi-Fi, with respect to their applicability to wireless avionics. The Wireless Avionics Intra-Communications (WAIC) objectives document, ITU-R M.2197, describes a number of applications of wireless avionics, and lists requirements specifications for each. Additionally, it describes models for compartments and areas of aircraft or vehicles in which wireless avionics would be applied. This exploratory study attempts to map Jeeva's Passive Radio technology to those scenarios outlined in the ITU-R M.2197 operational objectives document, and determine the areas and applications for which it is most suitable. Jeeva Passive Radio operates differently than conventional radios. In a conventional radio, a sensor-connected radio node must actively emit a signal in order to communicate. In a Jeeva Passive Radio system, that node instead simply reflects radio frequency energy which is emitted by another nearby device (called the Companion), which can be "plugged in" or otherwise has access to more power. Using reflections, a data packet can be generated and interpreted by a standard receiver. This method of communication inherently uses less energy, resulting in the potential for far lower power consumption and thus far longer battery life. Overall, 68.4% of use cases described by the ITU-R M.2197 operational objectives document were found to be addressable by Jeeva's Passive Radio systems (26 addressable of 38 total), with 26 of those best addressable by Wanscatter and three found to be best addressable with passive Wi-Fi. See Section 4.2 for a detailed breakdown of application suitability. The most fitting types of applications were in the LI (Low-rate Indoors) and LO (Low-rate Outdoors) categories, where lower rates were acceptable and thus Wanscatter could be applied and its much better uplink sensitivity leveraged. Jeeva has identified the Wanscatter (Chirp Spread Spectrum) system as likely holding the most promise for applications such as those outlined in the ITU-R M.2197 operational objectives document. We recommend that Wanscatter be a technology considered for adoption in wireless avionics

What Do Healthy Rural Economies Look Like in the U.S., and How Might Conservation Organizations Help Support Them?

Report of the 2012 Berkley Workshop Held at the Wingspread Conference Center, Racine,WI - July 201