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Parallel Regularized Maximum Likelihood Estimation For Proportional Odds Models
No full textOrdinal categorical random variables are random variables which take on values from a finite ordered set of possible values. They often result from qualitative assessments, such as rating a movie from one to five stars. Unlike continuous variables whose values are also ordered, ordinal categories are qualitative, so the distance between them may not be well-defined. This work focuses on computational aspects of predicting ordinal categorical random variables. We employ multinomial logistic models as the workhorse of our methodology. Beginning with the proportional odds version of the cumulative logit model, usually called the Proportional Odds Model (POM), we develop a regularized variant of that model. In particular, we study a special case of the generalized L1 regularized POM which we call the Fused Proportional Odds Model (FPOM) because it can result in coefficients whose values are equal, they can be fused together. FPOM incorporates a penalty term composed of a positive combination of terms: the absolute value of each coefficient, the absolute differences of coefficients, and the absolute differences of consecutive intercepts. This penalty makes sense when there is a notion of adjacency among coefficients, as occurs in signal processing, and when reduction of degrees of freedom is desired, e.g., in the context of high dimensional predictors. The geometry of this optimization, convex with edges and points, can aid finding a sparse solution, which is desirable in some contexts. As an illustration, we apply FPOM to a wine quality assessment dataset. We show, using various measures of prediction accuracy, that our model is competitive with other methods that have been applied to this data. Using a simulation, we show that FPOM can be used for variable selection. For many modern problems, especially those involving automated data collection, large quantities of data can be produced. Analyzing this data in a reasonable amount of time can be of practical importance. Accordingly, we study the use of parallel computation to speed up FPOM parameter estimation. Using computational nodes with two multi-core processors, we show that enabling parallel computation can result in an order of magnitude speedup on a single computational node
CERTIFIED NURSE AIDE SCOPE OF PRACTICE: IMPACT ON QUALITY OF CARE, NURSING AIDE BELIEFS, AND CLINICAL PRACTICE.
No full textOlder adults utilize more health care services than various other populations due to the complex nature of their health care needs. As acuity in health conditions increase, experienced care providers such as Certified Nurse Aides (CNAs) will be needed to offer hands-on care including care for the treatment of complex conditions. CNAs are essential caregivers, providing care that directly impacts resident outcomes. CNAs are currently only trained to provide a basic level of care and are not permitted to handle complex care tasks. CNAs do not have a scope of practice but manage care under the guidance of the 42 CFR � 483. There is not a clear understanding of what are the allowable delegated activities for the CNA beyond that of the basic skills. The variation of allowable care tasks per state may result in confusion of what are the overall CNA job roles or scope. This dissertation described what are the allowable delegated activities for CNAs working in nursing facility settings. Further, this work determined if there was a difference in the clinical outcomes in states that had a basic versus states that had an expanded scope of practice for CNAs, and this dissertation described the self-efficacy expectations and care tasks performed among CNAs. Findings suggest that all states within the United States allow CNAs to manage basic care tasks, and 11 states allow CNAs to manage expanded care tasks. Findings also indicate that there was no difference in clinical outcomes, specifically the outcomes of ADLs, falls with major injury, restraint use, and pain when compared to the allowable care tasks managed by CNAs in each state. Finally, CNAs who worked in states that allowed for expanded care tasks had a stronger self-efficacy for performing expanded tasks when compared to CNAs who worked in states that only allow CNAs to manage basic tasks
Bayesian Adaptive Dose-finding Methods in Phase I Drug Combination Trials
No full textIn a single-agent dose-finding Phase I trial, the key underlying assumption is that toxicity probability increases monotonically with the dose level. However, in multi-agent trial, this assumption may not hold because the drug-drug interaction effect can either decrease or increase the joint toxicity as compared to either one used alone, which may lead to an unforeseen toxicity probability surface. In the first part of the dissertation, we develop a novel adaptive dose-finding approach which can be applied to these kinds of multi-drug combination trials under the situation of non-monotonic toxicity probability surface. In the second part of the dissertation, we extend our investigation on the drug combination dose-finding trials with late-onset toxicity outcomes and have proposed a Bayesian adaptive dose-finding design under a nonignorable missing data mechanism, and where surrogate data are available. We evaluate the operating characteristics of the aforementioned methods and also compare them with existing methods through extensive simulation studies under various scenarios. The proposed methods demonstrate satisfactory performance in general
Physical Processes in the Atmospheric Boundary Layer with Implications for Air Quality
No full textOzone (O3) is a secondary pollutant dependent on complex photochemical reactions of nitrogen oxides (NOx) and volatile organic compounds (VOCs) and is sensitive to meteorological conditions that govern solar radiation, temperature, and wind speed/direction (Stockwell, 2011). The U.S. Environmental Protection Agency (USEPA) has classified O3 as one of the six criteria pollutants that is considered harmful to both plants and human health (Hollingsworth, 2007). The current study investigates the influence of the diurnal cycle of the BL on the surface air pollutants. Specifically, it examines how the nighttime and transition period turbulence impacts the concentration of ozone at the surface and in the atmospheric column during the following day. In order to complete the study, a series of models including the Weather Research and Forecasting (WRF) model and the Comprehensive Air Quality model with Extensions (CAMx) are used to simulate atmospheric conditions in the Maryland and Texas areas. BL processes such as the minimum diffusivity or BL parameterization within CAMx are investigated. The Blackadar scheme was found to artificially suppress the nocturnal BL height and appears to be the cause of a 15 ppbv high model bias. An experiment is then conducted where a minimum BL height of 160 m and an improvement of 7% in the median model bias are found in the Maryland area. With Maryland being in a NOx-limited regime, the same process of setting a minimum height is tested in the Texas area using the YSU scheme but minimal differences produced minuscule changes in the vertical diffusivity. The use of the Ri number improved the model bias by another 5 ppbv or 13% over using the Blackadar BL scheme. A new algorithm to predict the nocturnal BL depth is implemented into the WRF YSU scheme, which scales the Ribc with the Obukhov length adding a dependency on near surface properties of the flow. The algorithm is tested using meteorological surface measurements and tower measurements, along with pollutant measurements in the Texas and Maryland areas. The median model bias improved by 10% compared to using a static critical bulk Ri number
DEVELOPMENT OF ULTRA-MICRO ELECTRODE BASED BIOSENSORS
No full textHere I present a novel method for fabrication. characterization and optimization of micro scale, electrochemical aptamer-based sensors with the aim of developing sensors capable of quantitatively monitoring small molecule release from single cells in complex media. As a proof of concept, I have selected adenosine triphosphate (ATP) as a target molecule, since it is implicated in astrocyte communication in the central nervous system. Electrochemical methods provide powerful tools for the detection of molecular messenger release, but they are limited to molecules that are electrochemically active in a reasonable potential window. As such, current electrochemical methods for neuronal studies cannot detect ATP, since it is not electrochemically active in the preferred window for analysis. While the goal is to develop ATP sensors, the sensors developed can be generalized to any target molecule. The development of these sensors will enable study of gliotransmission with unprecedented spatiotemporal resolution and chemical specificity for analysis
Untitled [Dancer and two actresses in farm field]
No full textChelsey_Lee__MICA__Student_March_29__2014_at_0632PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Penn Station Reframed
No full textChris_Peregoy_UMBC_Penn_Station_Reframed_February_16__2014_at_0202PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Untitled [Band on stage behind bars]
No full textDavid_K__Kevin_David_J._Krout___UMBC__Visual_Arts_Student__Animal_Crackers_February_21__2014_at_0833PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Always One in the Crowd
No full textEllen_Lake__Oakland__California__Always_One_in_the_Crowd_February_02__2014_at_0431PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Lux
No full textErin_Fields__Harford_Community_College__Student__Lux_February_21__2014_at_0603PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe