Showing papers by "University of Florida published in 2005"

Locating the nodes: cooperative localization in wireless sensor networks

Abstract: Accurate and low-cost sensor localization is a critical requirement for the deployment of wireless sensor networks in a wide variety of applications. In cooperative localization, sensors work together in a peer-to-peer manner to make measurements and then forms a map of the network. Various application requirements influence the design of sensor localization systems. In this article, the authors describe the measurement-based statistical models useful to describe time-of-arrival (TOA), angle-of-arrival (AOA), and received-signal-strength (RSS) measurements in wireless sensor networks. Wideband and ultra-wideband (UWB) measurements, and RF and acoustic media are also discussed. Using the models, the authors have shown the calculation of a Cramer-Rao bound (CRB) on the location estimation precision possible for a given set of measurements. The article briefly surveys a large and growing body of sensor localization algorithms. This article is intended to emphasize the basic statistical signal processing background necessary to understand the state-of-the-art and to make progress in the new and largely open areas of sensor network localization research.

Dna methylation and human disease

Abstract: DNA methylation is a crucial epigenetic modification of the genome that is involved in regulating many cellular processes. These include embryonic development, transcription, chromatin structure, X chromosome inactivation, genomic imprinting and chromosome stability. Consistent with these important roles, a growing number of human diseases have been found to be associated with aberrant DNA methylation. The study of these diseases has provided new and fundamental insights into the roles that DNA methylation and other epigenetic modifications have in development and normal cellular homeostasis.

The Multifunctional Fish Gill: Dominant Site of Gas Exchange, Osmoregulation, Acid-Base Regulation, and Excretion of Nitrogenous Waste

Abstract: The fish gill is a multipurpose organ that, in addition to providing for aquatic gas exchange, plays dominant roles in osmotic and ionic regulation, acid-base regulation, and excretion of nitrogenous wastes Thus, despite the fact that all fish groups have functional kidneys, the gill epithelium is the site of many processes that are mediated by renal epithelia in terrestrial vertebrates Indeed, many of the pathways that mediate these processes in mammalian renal epithelial are expressed in the gill, and many of the extrinsic and intrinsic modulators of these processes are also found in fish endocrine tissues and the gill itself The basic patterns of gill physiology were outlined over a half century ago, but modern immunological and molecular techniques are bringing new insights into this complicated system Nevertheless, substantial questions about the evolution of these mechanisms and control remain

Mitochondrial DNA Mutations, Oxidative Stress, and Apoptosis in Mammalian Aging

Abstract: Mutations in mitochondrial DNA (mtDNA) accumulate in tissues of mammalian species and have been hypothesized to contribute to aging. We show that mice expressing a proofreading-deficient version of the mitochondrial DNA polymerase g (POLG) accumulate mtDNA mutations and display features of accelerated aging. Accumulation of mtDNA mutations was not associated with increased markers of oxidative stress or a defect in cellular proliferation, but was correlated with the induction of apoptotic markers, particularly in tissues characterized by rapid cellular turnover. The levels of apoptotic markers were also found to increase during aging in normal mice. Thus, accumulation of mtDNA mutations that promote apoptosis may be a central mechanism driving mammalian aging.

The Subsystems Approach to Genome Annotation and its Use in the Project to Annotate 1000 Genomes

Abstract: The release of the 1000th complete microbial genome will occur in the next two to three years. In anticipation of this milestone, the Fellowship for Interpretation of Genomes (FIG) launched the Project to Annotate 1000 Genomes. The project is built around the principle that the key to improved accuracy in high-throughput annotation technology is to have experts annotate single subsystems over the complete collection of genomes, rather than having an annotation expert attempt to annotate all of the genes in a single genome. Using the subsystems approach, all of the genes implementing the subsystem are analyzed by an expert in that subsystem. An annotation environment was created where populated subsystems are curated and projected to new genomes. A portable notion of a populated subsystem was defined, and tools developed for exchanging and curating these objects. Tools were also developed to resolve conflicts between populated subsystems. The SEED is the first annotation environment that supports this model of annotation. Here, we describe the subsystem approach, and offer the first release of our growing library of populated subsystems. The initial release of data includes 180 177 distinct proteins with 2133 distinct functional roles. This data comes from 173 subsystems and 383 different organisms.

A Meta-Analytic Test of the Challenge Stressor–Hindrance Stressor Framework: An Explanation for Inconsistent Relationships Among Stressors and Performance

Abstract: This article reports a meta-analytic test of a two-dimensional work stressor framework with respect to stressors' relationships with strains, motivation, and performance Hindrance stressors had a

A network-based analysis of systemic inflammation in humans

Abstract: Oligonucleotide and complementary DNA microarrays are being used to subclassify histologically similar tumours, monitor disease progress, and individualize treatment regimens1,2,3,4,5. However, extracting new biological insight from high-throughput genomic studies of human diseases is a challenge, limited by difficulties in recognizing and evaluating relevant biological processes from huge quantities of experimental data. Here we present a structured network knowledge-base approach to analyse genome-wide transcriptional responses in the context of known functional interrelationships among proteins, small molecules and phenotypes. This approach was used to analyse changes in blood leukocyte gene expression patterns in human subjects receiving an inflammatory stimulus (bacterial endotoxin). We explore the known genome-wide interaction network to identify significant functional modules perturbed in response to this stimulus. Our analysis reveals that the human blood leukocyte response to acute systemic inflammation includes the transient dysregulation of leukocyte bioenergetics and modulation of translational machinery. These findings provide insight into the regulation of global leukocyte activities as they relate to innate immune system tolerance and increased susceptibility to infection in humans.

Care of Children and Adolescents With Type 1 Diabetes A statement of the American Diabetes Association

Abstract: During recent years, the American Diabetes Association (ADA) has published detailed guidelines and recommendations for the management of diabetes in the form of technical reviews, position statements, and consensus statements. Recommendations regarding children and adolescents have generally been included as only a minor portion of these documents. For example, the most recent ADA position statement on “Standards of Medical Care for Patients With Diabetes Mellitus” (last revised October 2003) included “special considerations” for children and adolescents (1). Other position statements included age-specific recommendations for screening for nephropathy (2) and retinopathy (3) in children with diabetes. In addition, the ADA has published guidelines pertaining to certain aspects of diabetes that apply exclusively to children and adolescents, including care of children with diabetes at school (4) and camp (5) and a consensus statement on type 2 diabetes in children and adolescents (6). The purpose of this document is to provide a single resource on current standards of care pertaining specifically to children and adolescents with type 1 diabetes. It is not meant to be an exhaustive compendium on all aspects of the management of pediatric diabetes. However, relevant references are provided and current works in progress are indicated as such. The information provided is based on evidence from published studies whenever possible and, when not, supported by expert opinion or consensus (7). Several excellent detailed guidelines and chapters on type 1 diabetes in pediatric endocrinology texts exist, including those by the International Society of Pediatric and Adolescent Diabetes (ISPAD) (8), by the Australian Pediatric Endocrine Group (www.chw.edu/au/prof/services/endocrinology/apeg), in Lifshitz’s Pediatric Endocrinology (9–11), and by Plotnick and colleagues (12,13). Children have characteristics and needs that dictate different standards of care. The management of diabetes in children must take the major differences between children of various ages and …

The Association between Outside Directors, Institutional Investors and the Properties of Management Earnings Forecasts

Abstract: We investigate the relation of the board of directors and institutional ownership with the properties of management earnings forecasts. We find that firms with more outside directors and greater institutional ownership are more likely to issue a forecast and are inclined to forecast more frequently. In addition, these forecasts tend to be more specific, accurate and less optimistically biased. These results are robust to changes specification, Granger causality tests, and simultaneous equation analyses. The results are similar in the pre– and post–Regulation Fair Disclosure (Reg FD) eras. Additional analysis suggests that concentrated institutional ownership is negatively associated with forecast properties. This association is less negative in the post–Reg FD environment, which is consistent with Reg FD reducing the ability of firms to privately communicate information to select audiences.

Breakfast Habits, Nutritional Status, Body Weight, and Academic Performance in Children and Adolescents

Abstract: Breakfast has been labeled the most important meal of the day, but are there data to support this claim? We summarized the results of 47 studies examining the association of breakfast consumption with nutritional adequacy (nine studies), body weight (16 studies), and academic performance (22 studies) in children and adolescents. Breakfast skipping is highly prevalent in the United States and Europe (10% to 30%), depending on age group, population, and definition. Although the quality of breakfast was variable within and between studies, children who reported eating breakfast on a consistent basis tended to have superior nutritional profiles than their breakfast-skipping peers. Breakfast eaters generally consumed more daily calories yet were less likely to be overweight, although not all studies associated breakfast skipping with overweight. Evidence suggests that breakfast consumption may improve cognitive function related to memory, test grades, and school attendance. Breakfast as part of a healthful diet and lifestyle can positively impact children's health and well-being. Parents should be encouraged to provide breakfast for their children or explore the availability of a school breakfast program. We advocate consumption of a healthful breakfast on a daily basis consisting of a variety of foods, especially high-fiber and nutrient-rich whole grains, fruits, and dairy products.

Evaluation study of congestive heart failure and pulmonary artery catheterization effectiveness

Abstract: Context Pulmonary artery catheters (PACs) have been used to guide therapy in multiple settings, but recent studies have raised concerns that PACs may lead to increased mortality in hospitalized patients. Objective To determine whether PAC use is safe and improves clinical outcomes in patients hospitalized with severe symptomatic and recurrent heart failure. Design, setting, and participants The Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) was a randomized controlled trial of 433 patients at 26 sites conducted from January 18, 2000, to November 17, 2003. Patients were assigned to receive therapy guided by clinical assessment and a PAC or clinical assessment alone. The target in both groups was resolution of clinical congestion, with additional PAC targets of a pulmonary capillary wedge pressure of 15 mm Hg and a right atrial pressure of 8 mm Hg. Medications were not specified, but inotrope use was explicitly discouraged. Main outcome measures The primary end point was days alive out of the hospital during the first 6 months, with secondary end points of exercise, quality of life, biochemical, and echocardiographic changes. Results Severity of illness was reflected by the following values: average left ventricular ejection fraction, 19%; systolic blood pressure, 106 mm Hg; sodium level, 137 mEq/L; urea nitrogen, 35 mg/dL (12.40 mmol/L); and creatinine, 1.5 mg/dL (132.6 micromol/L). Therapy in both groups led to substantial reduction in symptoms, jugular venous pressure, and edema. Use of the PAC did not significantly affect the primary end point of days alive and out of the hospital during the first 6 months (133 days vs 135 days; hazard ratio [HR], 1.00 [95% confidence interval {CI}, 0.82-1.21]; P = .99), mortality (43 patients [10%] vs 38 patients [9%]; odds ratio [OR], 1.26 [95% CI, 0.78-2.03]; P = .35), or the number of days hospitalized (8.7 vs 8.3; HR, 1.04 [95% CI, 0.86-1.27]; P = .67). In-hospital adverse events were more common among patients in the PAC group (47 [21.9%] vs 25 [11.5%]; P = .04). There were no deaths related to PAC use, and no difference for in-hospital plus 30-day mortality (10 [4.7%] vs 11 [5.0%]; OR, 0.97 [95% CI, 0.38-2.22]; P = .97). Exercise and quality of life end points improved in both groups with a trend toward greater improvement with the PAC, which reached significance for the time trade-off at all time points after randomization. Conclusions Therapy to reduce volume overload during hospitalization for heart failure led to marked improvement in signs and symptoms of elevated filling pressures with or without the PAC. Addition of the PAC to careful clinical assessment increased anticipated adverse events, but did not affect overall mortality and hospitalization. Future trials should test noninvasive assessments with specific treatment strategies that could be used to better tailor therapy for both survival time and survival quality as valued by patients.

Lake responses to reduced nutrient loading - an analysis of contemporary long-term data from 35 case studies

Abstract: SUMMARY 1. This synthesis examines 35 long-term (5–35 years, mean: 16 years) lake re-oligotrophication studies. It covers lakes ranging from shallow (mean depth <5 m and/or polymictic) to deep (mean depth up to 177 m), oligotrophic to hypertrophic (summer mean total phosphorus concentration from 7.5 to 3500 l gL )1 before loading reduction), subtropical to temperate (latitude: 28–65� ), and lowland to upland (altitude: 0–481 m). Shallow northtemperate lakes were most abundant. 2. Reduction of external total phosphorus (TP) loading resulted in lower in-lake TP concentration, lower chlorophyll a (chl a) concentration and higher Secchi depth in most lakes. Internal loading delayed the recovery, but in most lakes a new equilibrium for TP

Prognostic value of usual gait speed in well-functioning older people--results from the Health, Aging and Body Composition Study.

Abstract: OBJECTIVES: To define clinically relevant cutpoints for usual gait speed and to investigate their predictive value for health-related events in older persons. DESIGN: Prospective cohort study. SETTING: Health, Aging and Body Composition Study. PARTICIPANTS: Three thousand forty-seven well-functioning older persons (mean age 74.2). MEASUREMENTS: Usual gait speed on a 6-m course was assessed at baseline. Participants were randomly divided into two groups to identify (Sample A; n = 2,031) and then validate (Sample B; n = 1,016) usual gait-speed cutpoints. Rates of persistent lower extremity limitation events (mean follow-up 4.9 years) were calculated according to gait speed in Sample A. A cutpoint (defining high- (<1 m/s) and low risk (≥1 m/s) groups) was identified based on persistent lower extremity limitation events. The predictive value of the identified cutpoints for major health-related events (persistent severe lower extremity limitation, death, and hospitalization) was evaluated in Sample B using Cox regression analyses. RESULTS: A graded response was seen between risk groups and health-related outcomes. Participants in the high-risk group had a higher risk of persistent lower extremity limitation (rate ratio (RR) = 2.20, 95% confidence interval (CI) = 1.76-2.74), persistent severe lower extremity limitation (RR = 2.29, 95% CI = 1.63-3.20), death (RR = 1.64, 95% CI = 1.14-2.37), and hospitalization (RR = 1.48, 95% CI = 1.02-2.13) than those in the low-risk group. CONCLUSION: Usual gait speed of less than 1 m/s identifies persons at high risk of health-related outcomes in well-functioning older people. Provision of a clinically meaningful cutpoint for usual gait speed may facilitate its use in clinical and research settings.

Rapid acidification of the ocean during the Paleocene-Eocene thermal maximum.

Abstract: The Paleocene-Eocene thermal maximum (PETM) has been attributed to the rapid release of ∼2000 × 10 9 metric tons of carbon in the form of methane. In theory, oxidation and ocean absorption of this carbon should have lowered deep-sea pH, thereby triggering a rapid ( 100,000 years). These findings indicate that a large mass of carbon (»2000 × 10 9 metric tons of carbon) dissolved in the ocean at the Paleocene-Eocene boundary and that permanent sequestration of this carbon occurred through silicate weathering feedback.

Practice Parameters for Clinical Use of the Multiple Sleep Latency Test and the Maintenance of Wakefulness Test

Abstract: Characterization of excessive sleepiness is an important task for the sleep clinician, and assessment requires a thorough history and in many cases, objective assessment in the sleep laboratory. These practice parameters were developed to guide the sleep clinician on appropriate clinical use of the Multiple Sleep Latency Test (MSLT), and the Maintenance of Wakefulness Test (MWT). These recommendations replace those published in 1992 in a position paper produced by the American Sleep Disorders Association. A Task Force of content experts was appointed by the American Academy of Sleep Medicine to perform a comprehensive review of the scientific literature and grade the evidence regarding the clinical use of the MSLT and the MWT. Practice parameters were developed based on this review and in most cases evidence based methods were used to support recommendations. When data were insufficient or inconclusive, the collective opinion of experts was used to support recommendations. These recommendations were developed by the Standards of Practice Committee and reviewed and approved by the Board of Directors of the American Academy of Sleep Medicine. The MSLT is indicated as part of the evaluation of patients with suspected narcolepsy and may be useful in the evaluation of patients with suspected idiopathic hypersomnia. The MSLT is not routinely indicated in the initial evaluation and diagnosis of obstructive sleep apnea syndrome, or in assessment of change following treatment with nasal continuous positive airway pressure (CPAP). The MSLT is not routinely indicated for evaluation of sleepiness in medical and neurological disorders (other than narcolepsy), insomnia, or circadian rhythm disorders. The MWT may be indicated in assessment of individuals in whom the inability to remain awake constitutes a safety issue, or in patients with narcolepsy or idiopathic hypersomnia to assess response to treatment with medications. There is little evidence linking mean sleep latency on the MWT with risk of accidents in real world circumstances. For this reason, the sleep clinician should not rely solely on mean sleep latency as a single indicator of impairment or risk for accidents, but should also rely on clinical judgment. Assessment should involve integration of findings from the clinical history, compliance with treatment, and, in some cases, objective testing using the MWT. These practice parameters also include recommendations for the MSLT and MWT protocols, a discussion of the normative data available for both tests, and a description of issues that need further study.

Core self-evaluations and job and life satisfaction: The role of self-concordance and goal attainment

Abstract: The present study tested a model explaining how the core self-evaluations (i.e., positive self-regard) concept is linked to job and life satisfaction. The self-concordance model, which focuses on motives underlying goal pursuit, was used as an explanatory framework. Data were collected from 2 samples: (a) 183 university students (longitudinal measures of goal attainment and life satisfaction were used) and (b) 251 employees (longitudinal measures of goal attainment and job satisfaction were utilized). In both studies, the core self-evaluations concept was positively related to goal self-concordance, meaning that individuals with positive self-regard were more likely to pursue goals for intrinsic and identified (value-congruent) reasons. Furthermore, in both studies, goal self-concordance was related to satisfaction (job satisfaction in Study 1 and life satisfaction in Study 2).

The Gator Tech Smart House: a programmable pervasive space

Abstract: Research groups in both academia and industry have developed prototype systems to demonstrate the benefits of pervasive computing in various application domains. Unfortunately, many first-generation pervasive computing systems lack the ability to evolve as new technologies emerge or as an application domain matures. To address this limitation, the University of Florida's Mobile and Pervasive Computing Laboratory is developing programmable pervasive spaces in which a smart space exists as both a runtime environment and a software library. Service discovery and gateway protocols automatically integrate system components using generic middleware that maintains a service definition for each sensor and actuator in the space. The Gator Tech Smart House in Gainesville, Florida, is the culmination of more than five years of research in pervasive and mobile computing. The project's goal is to create assistive environments such as homes that can sense themselves and their residents and enact mappings between the physical world and remote monitoring and intervention services.

Beyond STS: A research‐based framework for socioscientific issues education

Abstract: An important distinction can be made between the science, technology, and society (STS) movement of past years and the domain of socioscientific issues (SSI). STS education as typically practiced does not seem embedded in a coherent developmental or sociological framework that explicitly considers the psychological and epistemological growth of the child, nor the development of character or virtue. In contrast, the SSI movement focuses on empowering students to consider how science-based issues reflect, in part, moral principles and elements of virtue that encompass their own lives, as well as the physical and social world around them. The focus of this paper is to describe a research-based framework of current research and practice that identifies factors associated with reasoning about socioscientific issues and provide a working model that illustrates theoretical and conceptual links among key psychological, sociological, and developmental factors central to SSI and science education. © 2005 Wiley Periodicals, Inc. Sci Ed, 89:357–377, 2005

INTERNET USES AND GRATIFICATIONS: A Structural Equation Model of Interactive Advertising

Abstract: This study investigates the interactivity construct in terms of its antecedents (i.e., motivations for using the Internet) and consequences (i.e., attitude toward the site, attitude toward the brand, and purchase intention). A structural equation model was developed for an empirical test, based on uses and gratification theory applied to the interactivity context. A sample of 385 college students in the United States and Korea participated in the experiment. The findings suggest that consumers who have high information motivations are more likely to engage in human-message interaction on a Web site, whereas social interaction motivations are more strongly related to human-human interaction. Both human-message and human-human interactions had a positive effect on attitude toward the site, which leads to positive attitude toward the brand and purchase intention.

A Comprehensive Survey of the Plasmodium Life Cycle by Genomic, Transcriptomic, and Proteomic Analyses

Abstract: Plasmodium berghei and Plasmodium chabaudi are widely used model malaria species. Comparison of their genomes, integrated with proteomic and microarray data, with the genomes of Plasmodium falciparum and Plasmodium yoelii revealed a conserved core of 4500 Plasmodium genes in the central regions of the 14 chromosomes and highlighted genes evolving rapidly because of stage-specific selective pressures. Four strategies for gene expression are apparent during the parasites' life cycle: (i) housekeeping; (ii) host-related; (iii) strategy-specific related to invasion, asexual replication, and sexual development; and (iv) stage-specific. We observed posttranscriptional gene silencing through translational repression of messenger RNA during sexual development, and a 47-base 3' untranslated region motif is implicated in this process.

Uric Acid–Induced C-Reactive Protein Expression: Implication on Cell Proliferation and Nitric Oxide Production of Human Vascular Cells

Abstract: Recent experimental and human studies have shown that hyperuricemia is associated with hypertension, systemic inflammation, and cardiovascular disease mediated by endothelial dysfunction and pathologic vascular remodeling Elevated levels of C-reactive protein (CRP) have emerged as one of the most powerful independent predictors of cardiovascular disease In addition to being a marker of inflammation, recent evidence suggests that CRP may participate directly in the development of atherosclerotic vascular disease For investigating whether uric acid (UA)-induced inflammatory reaction and vascular remodeling is related to CRP, the UA-induced expression of CRP in human vascular smooth muscle cells (HVSMC) and human umbilical vein endothelial cells (HUVEC) was examined, as well as the pathogenetic role of CRP in vascular remodeling It is interesting that HVSMC and HUVEC expressed CRP mRNA and protein constitutively, revealing that vascular cells are another source of CRP production UA (6 to 12 mg/dl) upregulated CRP mRNA expression in HVSMC and HUVEC with a concomitant increase in CRP release into cell culture media Inhibition of p38 or extracellular signal-regulated kinase 44/42 significantly suppressed UA-induced CRP expression, implicating these pathways in the response to UA UA stimulated HVSMC proliferation whereas UA inhibited serum-induced proliferation of HUVEC assessed by 3H-thymidine uptake and cell counting, which was attenuated by co-incubation with probenecid, the organic anion transport inhibitor, suggesting that entry of UA into cells is responsible for CRP expression UA also increased HVSMC migration and inhibited HUVEC migration In HUVEC, UA reduced nitric oxide (NO) release Treatment of vascular cells with anti-CRP antibody revealed a reversal of the effect of UA on cell proliferation and migration in HVSMC and NO release in HUVEC, which suggests that CRP expression may be responsible for UA-induced vascular remodeling This is the first study to show that soluble UA, at physiologic concentrations, has profound effects on human vascular cells The observation that UA alters the proliferation/migration and NO release of human vascular cells, mediated by the expression of CRP, calls for careful reconsideration of the role of UA in hypertension and vascular disease

A survey of nonlinear conjugate gradient methods

Abstract: This paper reviews the development of dierent versions of nonlinear conjugate gradient methods, with special attention given to global convergence properties.