University of Maryland, Baltimore County
Not a member yet
17643 research outputs found
Sort by
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
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
EXPLOITING THE ROLE OF POLARITY IN CITATION ANALYSIS
No full textCitation analysis has been widely used as an important factor in the assessment of research impact, which plays a role in advancing an academic field and in recognizing the research reputation and contribution of papers, authors, groups, institutions, and journals. Traditional citation analysis methods are based on the counts of citations or publications. Despite that more recent bibliometric indicators such as the H-index attempts to address the quality of publications, they are still based on statistical counts. Consequently, extant methods for citation analysis have largely overlooked the context in which articles are referenced such as the opinions of the citing authors, and have not been able to resolve the inconsistent findings about the impact of self-citations. The primary objective of this research is to address the limitations of the state-of-the-art citation analysis methods by examining the context as well as content of citations. The context is manifested in the polarity and the location of citations. Specifically, the polarity of citations is classified through content analysis into one of the three categories: positive, negative and neutral. The location of citations was measured in terms of common structural components of a research article. The secondary objective of the research is to examine the possible influence of self-citation on the outcome of citation analysis. The proposed methods for citation analysis are evaluated using real-world data collected from digital databases of publications. Using the traditional count based method as the baseline, the experiment results demonstrate that the proposed methods not only offer a new perspective for citation analysis but also provide an alternative explanation for the influence of self-citations
INVESTIGATING THE CHLAMYDOMONAS REINHARDTII CALVIN CYCLE ENZYME GENES FBP1 AND SBP1: REGULATION AND EFFECT OF OVEREXPRESSION ON GROWTH
No full textMicroalgae have great potential for generating biofuels, pharmaceuticals, and other commercially valuable products. The goal of this thesis project was to improve this potential by investigating the expression and function of two key Calvin cycle enzymes in Chlamydomonas reinhardtii. Overexpression of sedoheptulose-1,7-bisphosphatase (SBPase) and fructose-1,6-bisphosphatase (FBPase) improves carbon fixation and growth rate in higher plants, but nothing has been reported regarding the role of these enzymes in photosynthetic output and biomass in C. reinhardtii, a model green alga. I first set out to determine how overexpression of C. reinhardtii SBPase affects Chlamydomonas growth by making nuclear transgenic lines expressing the SBPase-encoding gene SBP1 under control of the HSP70A/RBCS2 promoter and RBCS2 3'UTR. One transgenic line that overexpressed SBPase showed a promising result by reaching the exponential and stationary growth phases faster than the control strain, but expression of transgenic SBPase in this strain diminished significantly within 6 months, so I next set out to overexpress SBP1 and the FBPase encoding gene (FBP1) directly in the chloroplast, to avoid the possibility of gene silencing. To this end, I generated new chloroplast expression vectors with C. reinhardtii FBP1 and SBP1 coding sequences synthesized with C. reinhardtii chloroplast codon-bias and flanked with 5'psbD and 3'psbA regulatory sequences. The FBP1 vector integrated properly into the chloroplast genome and all FBP1 transformants tested accumulated ~4-fold increased levels of FBPase protein and 1.5-fold increased levels of FBPase activity; unfortunately, however, none of the SBP1 transformants expressed SBPase protein. Surprisingly, the FBPase-overexpressing transformants did not grow faster than the wild type, and in fact under mixotrophic conditions with 5% CO2 they grew more slowly and reached a maximum cell density that was 1.5-fold lower than the wild type did, and under photoautotrophic conditions they grew more slowly and reached maximum cell densities that were 1.4-fold lower (atmospheric CO2) and 1.7-fold lower (5% CO2) than the wild type. To learn more about regulation of FBP1 and SBP1 mRNA and FBPase and SBPase protein levels I cultured C. reinhardtii cells photoautotrophically under 12 hour light:12 hour dark conditions and analyzed mRNA levels by RT-qPCR and protein by western blot. I found FBP1 and SBP1 transcripts to be highly inducible by light, up to ~8 and ~9 fold, respectively, while FBPase and SBPase protein levels were only modestly elevated in the light ~2.5 and ~6 fold, respectively. So in conclusion, I determined that Chlamydomonas FBP1 and SBP1 appear to be light-regulated genes, that overexpressing SBPase might be a promising strategy for improving microalgal growth, but that overexpression of FBPase has a neutral or detrimental effect on growth and biomass productivity in C. reinhardtii, depending on growth conditions
Comparison of Cloud Security Standards & Cloud Security control recommendation System
No full textCloud services are becoming an essential part of many organizations. Cloud providers have to adhere to security and privacy policies to ensure their users' data remains confidential and secure. On one end, cloud providers are implementing their own security and privacy controls. On the other hand, standards bodies like Cloud Security Alliance (CSA), International Organization for Standards (ISO), National Institute for Standards and Technology (NIST), etc. are developing broad standards for cloud security. In this paper we provide a comprehensive analysis of the cloud security standards that are being developed and how they compare with the security controls of cloud providers. Our study is mainly focused on policies about mobility of resources, identity and access management, data protection, incident response & audit and assessment. This paper will help consumer organizations with their compliance needs by evaluating the security controls and policies of cloud providers and assisting them in identifying their enterprise cloud security policies
Controls on Reach Scale Hydrologic Response in Urban Streams and Implications for Restoration Design
No full textThis dissertation explored the nature of hydraulic controls on flow paths and residence times in the channel and riparian zone in two highly urban and two suburban 2nd-3rd order streams in the Baltimore metropolitan region. The influence of urban development and in-stream infrastructure on flow patterns across the flow frequency spectrum were compared to natural features in the channel and riparian zone that have similar effects on flow patterns. This work was motivated by the recognition that the urban stream syndrome paradigm of simplified channel geometry associated with extremes of low and high flow does not account for the full range of interactions between urban watershed hydrology, riparian zone morphology, and urban infrastructure. First, to overcome technical obstacles associated with measuring discharge in flashy urban streams, an innovative methodology is presented in Chapter 2 for extrapolating the high end of discharge rating curves in four urban streams, the results of which were used to more accurately quantify the hydrologic response of the watersheds subsequently studied in this dissertation. In Chapter 3, the goal was to assess how a spectrum of channel and riparian zone morphologies affect the behavior of floodwaves generated from an urban landscape. A degraded urban non-alluvial headwater stream experienced almost pure floodwave translation under existing conditions and also when routed through a planned restoration design intended to improve connectivity with the adjacent riparian zone. Even in a third scenario where the upland corridor was removed and the floodplain was widened to an extreme extent there was little change in the hydrograph routed through the restoration reach. Only in an extremely unrealistic scenario in which the water was stored without release was there a significant change to the hydrographs. For these designs, simply increasing floodplain connectivity did not significantly alter the hydrographs. Next, the effects of a long, broad alluvial riparian zone in a suburban watershed on the properties of floodwaves were assessed. Floods that occur naturally in this watershed overwhelmed the storage capacity of the floodplain and experienced translation, while significant attenuation was observed when hydrographs with large peaks and narrow time bases from a highly impervious headwater urban watershed were routed through this alluvial valley. In Chapter 4, the relationships between longitudinal channel geometries, urban infrastructure, channel-spanning blockages, and mean hydraulic residence times under base flow conditions were also explored. Results show that road crossings create abrupt, non-erodible knickpoints in the channel which exert a strong effect on the distribution of elevation drops in water surface, similar to the controlling influence of channel blockages on channel forming processes. Modeling results across the spectrum of base flows indicate that these urban structures can play a role in controlling flow patterns and residence time, and that channel-spanning blockages and other restoration structures have a significant influence on estimates of in-channel residence time. This work is an important contribution to our understanding of the mechanisms controlling the propagation and storage of surface waters in urban stream networks and adjacent riparian zones, and helps to better define the efficacy of stream restoration practices
The role of sexual selection in darter speciation
No full textSexual selection results from the competition over mating opportunities in natural populations. Just as natural selection favors traits that increase survival and fecundity, sexual selection favors traits that increase mating opportunities and fertilization success. These two processes cause changes within populations but are also important in driving divergence between populations. Speciation by divergent natural selection, also called ecological speciation, is now a widely accepted driver of diversity; however the role of sexual selection is less concrete. Speciation by sexual selection is thought to occur via divergence in female mating preferences between populations followed by coevolution of male mating traits. These differences eventually lead to behavioral reproductive isolation as female preferences in one population no longer correspond to male traits in another. Although verbal and quantitative models demonstrate the plausibility of speciation by sexual selection, empirical examples are relatively few and evidence often comes from comparative datasets that rely on proxy measures of divergent sexual selection. Additionally, natural and sexual selection often interact making it difficult to distinguish speciation by sexual selection alone. Here, I address the potential for speciation by natural selection, by sexual selection, or by a combination of the two in a group of freshwater fishes commonly called darters (Etheostoma). My results suggest a primary role for sexual selection in early darter divergence. Interestingly, however, trait divergence and the evolution of behavioral isolation in darters appear to involve divergence in male aggressive responses and male mate preferences, respectively. Further, differences in the sexual environment predict total reproductive isolation between species while differences in the ecological environment do not. The influence of male behavior was unexpected given the overwhelming focus on divergence in female mate preferences in speciation by sexual selection models. Additionally, the potential for divergence in sexual selection to promote reproductive barriers outside behavioral isolation is surprising. Taken together, my results suggest that early darter divergence is driven by sexual selection and imply that the definition of speciation by sexual selection should be expanded to encompass the multiple mechanisms of sexual selection and how they might contribute to all reproductive barriers
Cyberbullying Behavior: Characteristics, Development, and Prevention
No full textAs the computer-mediated communication technologies constantly evolve, they create new opportunities for people to communicate with one another. Due to some inherent characteristics of these technologies such as anonymity and persistence, the emerging communication platforms have become a hotbed for cyberbullying - a type of cyber threat. Previous studies have shown that there is greater incidence of cyberbullying, and the negative impact such as social anxiety and a tendency for low self-esteem may even be carried over into adulthood. This research proposes a behavioral development model of cyber-bullying based on psychology theories. The model consists of seven main stages: blameless exposure, trying out, addiction, escalation, desensitization, and exhibition. Both quantitative and qualitative methods were used to test the proposed model. Survey questionnaire and interviews were selected as the main data collection methods. The results of regression analysis provide empirical support for the proposed model
Real-time Disaster Crisis Mapping based on Classification and Geo-location Recognition in Tweets.
No full textGenerally, one finds a large percentage of social media data, such as Tweets or Instagram, lack Geo-tagged location in their metadata, minimizing their use in generating Crisis Maps during natural and human caused disasters. In the following work, we will determine the 'at risk' areas for particular geographical locations(New York State for this current research) through post- disaster events such as Hurricane Sandy by the analysis of all tweets originating from the Geo-location area under consideration through exact string matching of location entities in tweet texts. In this study, we employ the 8 Million Twitter data set collected by Aulov, Price and Halem stored in Couch DB. We use a Named Entity Analysis algorithm, based on the Sultanik and Fink, to obtain locations of places mentioned tweets without geo -location tags, thus increasing spatial information relevant to developing real-time Crisis Maps of the affected disaster areas being impacted under hurricane events or other related extreme natural events. The algorithm for Geo-location recognition is based on forming N-Gram tokens extracted from text in the tweet which are further mapped against a location gazetteer to obtain the coordinates of the locations or places through exact string matching in the gazetteer. The location gazetteer contains key-value pairs of the name and alternate names of the places, belonging to New York State as 'key' and their coordinates as 'value'. Once all the locations are found, an augmented Crisis Map consisting of both Geo-tagged and inferred locations is shown to increase the observations of the impacted areas. We show that based on an increase in frequency of locations, `at-risk' areas can be distinguished from `impacted' areas