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2016

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Articles 11251 - 11280 of 12690

Full-Text Articles in Physical Sciences and Mathematics

De-Anonymization Attack Anatomy And Analysis Of Ohio Nursing Workforce Data Anonymization, Jacob M. Miracle Jan 2016

De-Anonymization Attack Anatomy And Analysis Of Ohio Nursing Workforce Data Anonymization, Jacob M. Miracle

Browse all Theses and Dissertations

Data generalization (anonymization) is a widely misunderstood technique for preserving individual privacy in non-interactive data publishing. Easily avoidable anonymization failures are still occurring 14 years after the discovery of basic techniques to protect against them. Identities of individuals in anonymized datasets are at risk of being disclosed by cyber attackers who exploit these failures. To demonstrate the importance of proper data anonymization we present three perspectives on data anonymization. First, we examine several de-anonymization attacks to formalize the anatomy used to conduct attacks on anonymous data. Second, we examine the vulnerabilities of an anonymous nursing workforce survey to convey how …


Computer Modeling Of A Solar Thermal System For Space Heating, Dhananjay D. Deshpande Jan 2016

Computer Modeling Of A Solar Thermal System For Space Heating, Dhananjay D. Deshpande

Browse all Theses and Dissertations

Most applications of flat plate, low-temperature solar thermal panels are for water heating, such as producing domestic hot water or raising the temperature of swimming pools. This is reasonable given that the large masses of water present in these systems inherently provide built-in thermal energy storage so that a separate energy storage tank does not have to be purchased. For a space heating system, extra thermal energy storage generally has to be purchased and is a detriment to the economics of these systems. Despite the economic drawbacks of solar thermal space heating, this thesis focuses on the size of thermal …


Analysis Of Adiabatic Batch Reactor, Erald Gjonaj Jan 2016

Analysis Of Adiabatic Batch Reactor, Erald Gjonaj

Undergraduate Journal of Mathematical Modeling: One + Two

A mixture of acetic anhydride is reacted with excess water in an adiabatic batch reactor to form an exothermic reaction. The concentration of acetic anhydride and the temperature inside the adiabatic batch reactor are calculated with an initial temperature of 20°C, an initial temperature of 30°C, and with a cooling jacket maintaining the temperature at a constant of 20°C. The graphs of the three different scenarios show that the highest temperatures will cause the reaction to occur faster.


Algorithms Leveraging Smartphone Sensing For Analyzing Explosion Events, Srinivas Chakravarthi Thandu Jan 2016

Algorithms Leveraging Smartphone Sensing For Analyzing Explosion Events, Srinivas Chakravarthi Thandu

Doctoral Dissertations

"The increasing frequency of explosive disasters throughout the world in recent years have created a clear need for the systems to monitor for them continuously to improve the post-disaster emergency events such as rescue and recovery operations. Disasters both man-made and natural are unfortunate and not preferred, however monitoring them may be a lifesaving phenomenon in emergency scenarios. Dedicated sensors deployed in the public places and their associated networks to monitor such events may be inadequate and must be complemented for making the monitoring more pervasive and effective. In the recent past, modern smartphones with significant processing, networking and storage …


Suppression Of Interfering Ions By Using Ionic Liquid And Micelle Moieties In Spectrofluorimetric Analysis Of Manganese, Özlem Öter, Müge Aydin, Kadri̇ye Erteki̇n Jan 2016

Suppression Of Interfering Ions By Using Ionic Liquid And Micelle Moieties In Spectrofluorimetric Analysis Of Manganese, Özlem Öter, Müge Aydin, Kadri̇ye Erteki̇n

Turkish Journal of Chemistry

Eosin-Y exhibits high affinity and emission based spectral response to most of the major ions in water samples. In the present study we performed selective spectrofluorimetric analysis of manganese with eosin-Y in the presence of potential interferents. We employed green chemistry reagents, ionic liquids (ILs) and two different micelles, to suppress the effect of conventional cations and anions on the response of eosin-Y. The experimental data revealed that different test moieties caused enhanced analytical response to Mn$^{2+}$. The highest analytical signal of eosin-Y was obtained in the presence of Triton X-100 at a concentration of 2.0 $\times $ 10$^{-3}$ mol …


Crystal Engineering Of A Family Of Hybrid Ultramicroporous Materials Based Upon Interpenetration And Dichromate Linkers, Hayley S. Scott, Naoki Ogiwara, Kai-Jie Chen, David G. Madden, Tony Pham, Katherine Forrest, Brian Space, Satoshi Horike, John J. Perry Iv, Susumu Kitagawa, Michael J. Zaworotko Jan 2016

Crystal Engineering Of A Family Of Hybrid Ultramicroporous Materials Based Upon Interpenetration And Dichromate Linkers, Hayley S. Scott, Naoki Ogiwara, Kai-Jie Chen, David G. Madden, Tony Pham, Katherine Forrest, Brian Space, Satoshi Horike, John J. Perry Iv, Susumu Kitagawa, Michael J. Zaworotko

Chemistry Faculty Publications

A new family of 2-fold interpenetrated primitive cubic (pcu) networks of formula [M(L)2(Cr2O7)]n (M = Co2+, Ni2+, Cu2+ and Zn2+; L = 4,4′-azopyridine), DICRO-3-M-i, has been synthesised and their structures, permanent porosity and gas sorption properties were comprehensively characterised. Molecular simulations indicate that CO2 molecules occupy both of the two distinct ultramicropores that run through this isostructural series. The orientation of the Cr2O72− pillars is thought to contribute to high isosteric enthalpy of adsorption (Qst) …


Gis Data: Prince George County And The City Of Hopewell, Virginia Tidal Marsh Inventory, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie G. Bradshaw, David Stanhope, Karen Duhring, Jessica Hendricks, David Weiss, Carl Hershner Jan 2016

Gis Data: Prince George County And The City Of Hopewell, Virginia Tidal Marsh Inventory, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie G. Bradshaw, David Stanhope, Karen Duhring, Jessica Hendricks, David Weiss, Carl Hershner

Data

The 2016 Tidal Marsh Inventory update for Prince George County and the City of Hopewell, Virginia was generated using on-screen digitizing techniques in the most recent version of ArcGIS® - ArcMap while viewing conditions observed in the most recent imagery from the Virginia Base Mapping Program (VBMP). Dominant plant community types were primarily determined during field surveys from shallow-draft boats moving along the shoreline. Land-based surveys were performed in some locations. One shapefile is developed that portrays tidal marsh areas represented as polygons. A metadata file accompanies the shapefile to define attribute accuracy, data development, and any use restrictions that …


Gis Data: Accomack County, Virginia Tidal Marsh Inventory, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, Kory Angstadt, Christine Tombleson, Karen Duhring, Kallie Brown, Jessica Hendricks, David Weiss, Carl Hershner Jan 2016

Gis Data: Accomack County, Virginia Tidal Marsh Inventory, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, Kory Angstadt, Christine Tombleson, Karen Duhring, Kallie Brown, Jessica Hendricks, David Weiss, Carl Hershner

Data

The 2016 Tidal Marsh Inventory update for Accomack County, Virginia was generated using on-screen digitizing techniques in the most recent version of ArcGIS® - ArcMap while viewing conditions observed in the most recent imagery from the Virginia Base Mapping Program (VBMP). Dominant plant community types were primarily determined during field surveys from shallow-draft boats moving along the shoreline. Land-based surveys were performed in some locations. One shapefile is developed that portrays tidal marsh areas represented as polygons. A metadata file accompanies the shapefile to define attribute accuracy, data development, and any use restrictions that pertain to the data.


The Dilemma Of Derelict Gear: Datasets, Andrew M. Scheld, Donna M. Bilkovic, Kirk J. Havens Jan 2016

The Dilemma Of Derelict Gear: Datasets, Andrew M. Scheld, Donna M. Bilkovic, Kirk J. Havens

Data

No abstract provided.


Gis Data: Accomack County, Virginia Shoreline Inventory Report, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, Kory Angstadt, Christine Tombleson, Karen Duhring, Kallie Brown, Jessica Hendricks, David Weiss, Carl H. Hershner Jan 2016

Gis Data: Accomack County, Virginia Shoreline Inventory Report, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, Kory Angstadt, Christine Tombleson, Karen Duhring, Kallie Brown, Jessica Hendricks, David Weiss, Carl H. Hershner

Data

The 2016 Inventory for Accomack County was generated using on-screen, digitizing techniques in ArcGIS® - ArcMap v10.2.2 while viewing conditions observed in Bing high resolution oblique imagery, Google Earth, and 2013 imagery from the Virginia Base Mapping Program (VBMP). Four GIS shapefiles are developed. The first describes land use and bank conditions (AccomackCo_lubc_2016). The second portrays the presence of beaches (AccomackCo_beaches_2016). The third reports shoreline structures that are described as arcs or lines (e.g. riprap) (AccomackCo_sstru_2016). The final shapefile includes all structures that are represented as points (e.g. piers) (AccomackCo_astru_2016). The metadata file accompanies the shapefiles and defines attribute accuracy, …


Gis Data: Prince George County And The City Of Hopewell, Virginia Shoreline Inventory Report, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, David Stanhope, Karen Duhring, Jessica Hendricks, David Weiss, Carl Hershner Jan 2016

Gis Data: Prince George County And The City Of Hopewell, Virginia Shoreline Inventory Report, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, David Stanhope, Karen Duhring, Jessica Hendricks, David Weiss, Carl Hershner

Data

The 2016 Inventory for Prince George County and the City of Hopewell was generated using on-screen, digitizing techniques in ArcGIS® - ArcMap v10.2.2 while viewing conditions observed in Bing high resolution oblique imagery, Google Earth, and 2013 imagery from the Virginia Base Mapping Program (VBMP). Four GIS shapefiles are developed. The first describes land use and bank conditions (PrinceGeorge_Hopewell _lubc_2016). The second portrays the presence of beaches (PrinceGeorge_Hopewell_beaches_2016). The third reports shoreline structures that are described as arcs or lines (e.g riprap) (PrinceGeorge_Hopewell _sstru_2016). The final shapefile includes all structures that are represented as points (e.g. piers) (PrinceGeorge_Hopewell_astru_2016). The metadata …


Gis Data: Accomack County Shoreline Management Model, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, Kory Angstadt, Christine Tombleson, Karen A. Duhring, Kallie Brown, Jessica Hendricks, David Weiss, Carl Hershner Jan 2016

Gis Data: Accomack County Shoreline Management Model, Marcia Berman, Karinna Nunez, Sharon Killeen, Tamia Rudnicky, Julie Bradshaw, Kory Angstadt, Christine Tombleson, Karen A. Duhring, Kallie Brown, Jessica Hendricks, David Weiss, Carl Hershner

Data

The Shoreline Management Model is a GIS spatial model that determines appropriate shoreline best management practices using available spatial data and decision tree logic. Available shoreline conditions used in the model include the presence or absence of tidal marshes, beaches, and forested riparian buffers, bank vegetation cover, bank height, wave exposure (fetch), nearshore water depth, and proximity of coastal development to the shoreline. The model output for shoreline best management practices is displayed in the locality Comprehensive Map Viewer. One GIS shapefile is developed that describes two arcs or lines representing practices in the upland area and practices at the …


Touch And Step Potential Analysis At 23.9kv To 4.16kv & 13.8kv To 4.16kv Distribution Substations With Pad-Mounted Transformers, Floating Grounds, And Other Exposed Ungrounded Metal Bodies Using Winigs, David Guillermo Guzman Jan 2016

Touch And Step Potential Analysis At 23.9kv To 4.16kv & 13.8kv To 4.16kv Distribution Substations With Pad-Mounted Transformers, Floating Grounds, And Other Exposed Ungrounded Metal Bodies Using Winigs, David Guillermo Guzman

Open Access Theses & Dissertations

An electrical substation is composed of various subsystems that allow for the effective and safe operation of the power grid. One of the subsystems integrating a conventional substation is defined as the ground grid system. This system allows for the effective operation of the power grid and all the electrical equipment connected to it by providing a ground potential reference, commonly known as the system ground. In addition, the ground grid system provides safety to the workers and the public transiting inside or living nearby a substation by reducing the step and touch potential (or voltage) levels present during a …


Regional Geochemical Mapping Of The Superior Upland Province; Ichnology Of The Cretaceous Mesilla Valley Formation, Cerro De Cristo Rey; A New Ichnospecies Of Cardioichnus From The Cretaceous (Albian) Of New Mexico; A Pedagogy For The Cerro De Cristo Rey Tracksite; Walking In The Footprints Of Dino, Eric J. Kappus Jan 2016

Regional Geochemical Mapping Of The Superior Upland Province; Ichnology Of The Cretaceous Mesilla Valley Formation, Cerro De Cristo Rey; A New Ichnospecies Of Cardioichnus From The Cretaceous (Albian) Of New Mexico; A Pedagogy For The Cerro De Cristo Rey Tracksite; Walking In The Footprints Of Dino, Eric J. Kappus

Open Access Theses & Dissertations

This is a multi-disciplinary study that covers a variety of geoscience topics on both international borders of the continental United States. This Dissertation is the product of several separate investigations. First is a report on the landscape geochemistry of the Superior Upland Province of Minnesota, Wisconsin, and Michigan, with regional maps of 37 chemical elements interpreted in terms of bedrock, glacial reworking, and anthropogenic influence. The next 2 sections are reports on the invertebrate ichnology of the Cretaceous Mesilla Valley Formation at Cerro de Cristo Rey, including the proposal of a new ichnospecies of echinoid resting trace, Cardioichnus biloba nov. …


Synthesis, Characterization, And Functional Evaluation Of Nanocomposites For Water Purification, Julio Eduardo Padilla Jan 2016

Synthesis, Characterization, And Functional Evaluation Of Nanocomposites For Water Purification, Julio Eduardo Padilla

Open Access Theses & Dissertations

The United Nations estimate that around 780 million people do not have access to clean and safe water and around 2.5 billion people do not have proper water sanitation. As a result, around 6-8 million people die each year due to water related diseases, such as cholera and dysentery, and disasters. As population increases the water problem will become more difficult to solve. Furthermore, climate change threatens to intensify water scarcity. The design of functional materials at the nanoscale offer unique solutions in molecular sorbents and catalytic systems that can develop into cost-effective solutions in water treatment by reducing the …


Insights Into Volcanic Processes Using Seismic Data Techniques, Ezer Patlan Jan 2016

Insights Into Volcanic Processes Using Seismic Data Techniques, Ezer Patlan

Open Access Theses & Dissertations

We present in this study numbers of technique to understand the volcanic processes using seismology. The types of techniques we used are earthquake location (double difference travel-time, cross-correlation tremor technique, and time reversal), stresses (b-values, focal mechanism), and tomography imagery (ambient noise tomography). The areas of study we focus on are in two different tectonic settings. The East Africa Rift System at Kenya, studying four volcanoes: Menengai Caldera, Silali, Paka, and Korosi volcanoes. The other area of study is located in a subduction zone in Central America, Salvador at San Miguel volcano.

In this study we aim to calculate accurate …


An Effective And Optimal Quality Control Approach For Green Energy Manufacturing Using Design Of Experiments Framework And Evolutionary Algorithm, Juan Alejandro Saavedra Jan 2016

An Effective And Optimal Quality Control Approach For Green Energy Manufacturing Using Design Of Experiments Framework And Evolutionary Algorithm, Juan Alejandro Saavedra

Open Access Theses & Dissertations

Quality Control (QC) and Quality Assurance (QA) strategies vary significantly across industries in the manufacturing sector depending on the product being built. Such strategies range from simple statistical analysis and process controls, decision-making process of reworking, repairing, or scraping defective product. This study proposes an optimal QC methodology in order to include rework stations during the manufacturing process by identifying the amount and location of these workstations. The factors that are considered to optimize these stations are cost, cycle time, reworkability and rework benefit. The goal is to minimize the cost and cycle time of the process, but increase the …


Identifying Non-Classical Active Sites As A Tool For Enzyme Inhibition, Marisol Serrano Jan 2016

Identifying Non-Classical Active Sites As A Tool For Enzyme Inhibition, Marisol Serrano

Open Access Theses & Dissertations

Chagas disease, caused by the parasite Trypanosoma cruzi, is an endemic life-threatening disease that affects mainly the heart. It remains the leading cause of heart failure in Latin American countries. Since current treatments against this parasite are highly toxic and somewhat ineffective, novel and more efficacious types of interventions are desired. Cruzain, identified as the major cathepsin for T. cruzi, plays a major role in the parasite's life cycle; making this enzyme very attractive for potential trypanocidal drugs discovery. The recombinant cruzain is synthesized as a zymogenic pro-protein (PCZN) which possesses a pro domain and a catalytic domain. In this …


Study Of No2 Photolysis Rate Coefficients For The Paso Del Norte Region, Pema Wangchuk Jan 2016

Study Of No2 Photolysis Rate Coefficients For The Paso Del Norte Region, Pema Wangchuk

Open Access Theses & Dissertations

The photolysis of nitrogen dioxide is one of the most influential chemical processes in the formation of photochemical air pollution. In this study, we compared simulated and measured nitrogen dioxide photolysis rate coefficients (J_(NO_2 )) for the Paso Del Norte (PdN) region. The Tropospheric Ultraviolet-Visible (TUV) radiation transfer model was used to calculate J_(NO_2 ) values. The measurements of hemi-spherically integrated, spectrally resolved solar photon flux between the wavelengths 400 and 700 nm were used to obtain the photolysis rate coefficients for ã??NOã??_2. Results are presented for a selected episode on July, 2015. The work investigated the use of measured …


Studying Grazing Behavior Of Cafeteria Roenbergensis With Two-Photon Microscopy, Faisal Abedin Abedin Jan 2016

Studying Grazing Behavior Of Cafeteria Roenbergensis With Two-Photon Microscopy, Faisal Abedin Abedin

Open Access Theses & Dissertations

Major innovations in recent years have largely revolutionized the fluorescence imaging. Two-photon fluorescence microscopy is one of them. Two photon fluorescence microscopy has evolved as an alternative to conventional single-photon confocal microscopy and has been shown to provide several advantages. These include three-dimensionally resolved fluorescence imaging of living cells deep within thick, strongly scattering samples, and reduced phototoxicity, enabling long term imaging of photosensitive biological specimens. The inherent three-dimensional resolution of TPE microscopy has been exploited in a number of studies wherein spatial discrimination of fluorescence signals at the micrometer and submicrometer scale within thick biological specimens proved critical. In …


Gravimetrically Characterizable Common Alkali Reducing Agents And Ligand Design Of A New Electron Rich Guanidinate, Efrain Maximiliano Castillo Jan 2016

Gravimetrically Characterizable Common Alkali Reducing Agents And Ligand Design Of A New Electron Rich Guanidinate, Efrain Maximiliano Castillo

Open Access Theses & Dissertations

SynThesis, isolation and characterization of 12 new alkali arenides was performed by the addition of the chelating base 18-crown-6. Electrochemistry, UV-vis/NIR spectroscopy and XRD studies were performed.

The incoorporation of an imidazolin-2-iminato group to the background of a guanidinate showed that this kind of ligand is electronically flexible and metal dependent. It was found that is more electron donating than some previously reported guanidinates and ketimine guanidinates.


Salt Tectonic Controls On Facies And Sequence Stratigraphy Of The Triassic Chinle Formation, Gypsum Valley Salt Wall, Colorado, Elizabeth Heness Jan 2016

Salt Tectonic Controls On Facies And Sequence Stratigraphy Of The Triassic Chinle Formation, Gypsum Valley Salt Wall, Colorado, Elizabeth Heness

Open Access Theses & Dissertations

This study focuses on mapping the facies geometry and depositional sequences of the Chinle Formation adjacent to the Gypsum Valley Salt Wall (GVSW). Interactions between salt tectonics and fluvial systems can affect sediment distribution. The upper Triassic Chinle Formation was deposited across the western U.S. in an intra-cratonic, fluvial environment. Throughout the Paradox Basin in Utah and Colorado, deformation associated with rising salt anticlines and subsiding minibasins coincided with Chinle deposition. In most areas, only small and isolated remnant Chinle outcrops actually expose the contact between Chinle sediments and the salt diapir. In Gypsum Valley three study areas were mapped …


Sample Size Estimation For Genomics Experiments With Dependent End Points, Desmond Koomson Jan 2016

Sample Size Estimation For Genomics Experiments With Dependent End Points, Desmond Koomson

Open Access Theses & Dissertations

In typical genomics studies involving numerous association tests of gene mutations with a disease, error rate control via multiplicity adjustment is paramount because even if all genes were to be non-differentially associated, we would still make some false positives. Many methods exist that incorporate the control of multiplicity for normally distributed endpoints in sample size estimation, but none addresses the issue for non-normally correlated endpoints.

One common practice in the literature is to assume an equal correlation among all differentially associated or expressed genes, thereby using the generalized binomial or beta-binomial model to compute the comparison-wise power of detecting these …


An Analysis Of The Impact Of The Csu Peer Leader Program On Student Performance In 2014-2015, Harrison E. Sharitt Jan 2016

An Analysis Of The Impact Of The Csu Peer Leader Program On Student Performance In 2014-2015, Harrison E. Sharitt

Theses and Dissertations

In efforts to retain students and increase student performance, Columbus State implemented a Peer Leader program. With access to archival data on the CSU Peer Leader Program, the goal of this project was to determine if the program at CSU had a significant impact on students’ course performance. The impact of the program was assessed by performing multiple regression analyses and ANOVA. Preliminary results showed that Columbus State’s Peer Leader program had a small, but statistically significant, positive impact on students’ final course grades.


Forecasting Customer Electricity Load Demand In The Power Trading Agent Competition Using Machine Learning, Saiful Abu Jan 2016

Forecasting Customer Electricity Load Demand In The Power Trading Agent Competition Using Machine Learning, Saiful Abu

Open Access Theses & Dissertations

Accurate electricity load demand forecasting is an important problem in managing the power grid for both economic and environmental reasons. The Power TAC simulation provides a platform to do research on smart grid energy generation and distribution systems. Brokers are the focus of the design task posed to developers by the system. The brokers work as self-interested entities that try to maximize profits by trading electricity across multiple markets. To be successful, a broker has to forecast the electricity demand for customers as accurately as possible so it can use this information to operate efficiently. My proposed forecasting method uses …


Dft Study On The Structure And Properties Of Vsc2n@C68, Surendra Bhatta Jan 2016

Dft Study On The Structure And Properties Of Vsc2n@C68, Surendra Bhatta

Open Access Theses & Dissertations

A computational study on the structure and electronic properties of the VSc2N@C68 molecule was carried out using the density functional theory. This molecule is based on the recent report on the synThesis of the VSc2N@C80 and V2ScN@C80 fullerenes. The Sc3N@C68 is also a stable endohedral fullerene that has a cage with fuse pentagonal rings. The doping by a V atom changes the structure as well as the spin state of the Sc3N@C68 from S=0 to S=1 state. Since the C68 has 6332 isomers, we have carried out an extensive search for the lowest energy structure of the C68 in several …


Evidence Of Active Rifts In The Southwest United States Using Geophysical Inversion Of Seismic Data, Sergio H. Celis Jan 2016

Evidence Of Active Rifts In The Southwest United States Using Geophysical Inversion Of Seismic Data, Sergio H. Celis

Open Access Theses & Dissertations

A continental rift represents a zone where the lithosphere has become thinner due to extensional forces associated with plate tectonics. Many of these rifts are still active, such as the East Africa rift, while others appear to be failed rifts. I build upon recent results of crustal structure for the southern section of the Rio Grande Rift using seismic data collected by USArray stations, and extend the analysis into the states of New Mexico, Oklahoma, Arkansas, and Louisiana to investigate the differences between active and failed rifts in the state of Texas. I collect two geophysical data sets, including receiver …


D-Dimer Levels Before Hiv Seroconversion Remain Elevated Even After Viral Suppression And Are Associated With An Increased Risk Of Non-Aids Events, Matthew S Freiberg, Ionut Bebu, Russell Tracy, Kaku So-Armah, Jason Okulicz, Anuradha Ganesan, Adam Armstrong, Thomas O'Bryan, David Rimland, Amy C Justice, Brian K Agan Jan 2016

D-Dimer Levels Before Hiv Seroconversion Remain Elevated Even After Viral Suppression And Are Associated With An Increased Risk Of Non-Aids Events, Matthew S Freiberg, Ionut Bebu, Russell Tracy, Kaku So-Armah, Jason Okulicz, Anuradha Ganesan, Adam Armstrong, Thomas O'Bryan, David Rimland, Amy C Justice, Brian K Agan

GW Biostatistics Center

The mechanism underlying the excess risk of non-AIDS diseases among HIV infected people is unclear. HIV associated inflammation/hypercoagulability likely plays a role. While antiretroviral therapy (ART) may return this process to pre-HIV levels, this has not been directly demonstrated. We analyzed data/specimens on 249 HIV+ participants from the US Military HIV Natural History Study, a prospective, multicenter observational cohort of >5600 active duty military personnel and beneficiaries living with HIV. We used stored blood specimens to measure D-dimer and Interleukin-6 (IL-6) at three time points: pre-HIV seroconversion, ≥6 months post-HIV seroconversion but prior to ART initiation, and ≥6 months post-ART …


Generalized Confidence Intervals And Fiducial Intervals For Some Epidemiological Measures., Ionut Bebu, G. Luta, T. Mathew, B. K. Agan Jan 2016

Generalized Confidence Intervals And Fiducial Intervals For Some Epidemiological Measures., Ionut Bebu, G. Luta, T. Mathew, B. K. Agan

GW Biostatistics Center

For binary outcome data from epidemiological studies, this article investigates the interval estimation of several measures of interest in the absence or presence of categorical covariates. When covariates are present, the logistic regression model as well as the log-binomial model are investigated. The measures considered include the common odds ratio (OR) from several studies, the number needed to treat (NNT), and the prevalence ratio. For each parameter, confidence intervals are constructed using the concepts of generalized pivotal quantities and fiducial quantities. Numerical results show that the confidence intervals so obtained exhibit satisfactory performance in terms of maintaining the coverage probabilities …


Significance Of Epicardial And Intrathoracic Adipose Tissue Volume Among Type 1 Diabetes Patients In The Dcct/Edic: A Pilot Study., Sirous Darabian, Jye-Yu C Backlund, Patricia A Cleary, Nasim Sheidaee, Ionut Bebu, John M. Lachin, Matthew J Budoff, Dcct/Edic Research Group Jan 2016

Significance Of Epicardial And Intrathoracic Adipose Tissue Volume Among Type 1 Diabetes Patients In The Dcct/Edic: A Pilot Study., Sirous Darabian, Jye-Yu C Backlund, Patricia A Cleary, Nasim Sheidaee, Ionut Bebu, John M. Lachin, Matthew J Budoff, Dcct/Edic Research Group

GW Biostatistics Center

Introduction

Type 1 diabetes (T1DM) patients are at increased risk of coronary artery disease (CAD). This pilot study sought to evaluate the relationship between epicardial adipose tissue (EAT) and intra-thoracic adipose tissue (IAT) volumes and cardio-metabolic risk factors in T1DM.

Method

EAT/IAT volumes in 100 patients, underwent non-contrast cardiac computed tomography in the Diabetes Control and Complications Trial /Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study were measured by a certified reader. Fat was defined as pixels’ density of -30 to -190 Hounsfield Unit. The associations were assessed using–Pearson partial correlation and linear regression models adjusted for gender and age …