3,765 research outputs found

    An Experimental Study of Potential Residential and Commercial Applications of Small-Scale Hybrid Power Systems

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    The research presented in this thesis provides an understanding of small-scale hybrid power systems. Experiments were conducted to identify potential applications of renewable energy in residential and commercial applications in the Rio Grande Valley of Texas. Solar and wind energy converted into electric energy was stored in batteries and inverted to power common household and commercial appliances. Several small to medium size hybrid power systems were setup and utilized to conduct numerous tests to study renewable energy prospects and feasibility for various applications. The experimental results obtained indicate that carefully constructed solar power systems can provide people living in isolated communities with sufficient energy to consistently meet their basic power needs

    Risk factors and rates of delayed symptomatic hyponatremia after transsphenoidal surgery: a systematic review

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    BACKGROUND: Delayed symptomatic hyponatremia (DSH) is among the most common reasons for readmission following transsphenoidal surgery. Patients can present with a large range of symptoms, requiring immediate attention and prolonging hospital stay. In rare and severe cases, DSH can result in death. While various risk factors for DSH have been investigated, there is still a need for better understanding in order to identify patients who are at risk. Clinicians can then take preventative measures to improve patient outcomes. A systematic review was performed to determine both predictors and rates of DSH after both endoscopic (eTSS) and microscopic transsphenoidal surgery (mTSS). METHODS: We conducted a systematic search through databases MEDLINE/PUBMED, MEBASE, and The Cochrane Library. Included studies were selected with the following criteria: (i) case series with at least 10 cases reported, (ii) adult patients who underwent eTSS or mTSS for pituitary adenomas, and (iii) reported occurrence of DSH (hyponatremia defined as blood sodium level <135 mEq/L) three days post-operatively. Data were analyzed using CMA V.3 Statistical Software (2014). RESULTS: We identified 10 case series that satisfied the inclusion criteria consisting of 2,947 patients with pituitary adenomas. The following were investigated as potential predictors of DSH: age, CSF leak, gender, and tumor size. Rates of DSH were found to be between 4 and 12 percent for both mTSS and eTSS. CONCLUSIONS: Age, gender, tumor size, rate of blood sodium level decline between post-operative day (POD) 4 and 7, and Cushing’s disease are potential predictors of DSH. A better understanding of these predictors can help clinicians identify patients at risk for DSH so preventative measures can be taken to reduce the deleterious effects of hyponatremia after transsphenoidal surgery

    Gifted Education: A Multi-Case Study on the Identification Process of Historically Underrepresented Students in Gifted Programs in North Carolina

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    The purpose of this multiple case study was to explore how Newland, Big Hills, and Edison Elementary, which are public elementary schools in North Carolina, identify gifted students who are historically underrepresented for placement in academically gifted classes. Based on statistical data from the Department of Education and the North Carolina Department of Public Instruction, there is a disparity between the identification of Whites, Blacks, and Hispanics, especially in impoverished communities. The study sought to understand the process of identification of gifted students and how it contributes to under-representation of Black, Hispanic, and impoverished students. The study revealed what social characteristics and demographic data are prioritized in the process and what factors and values influence the process of identification in these schools by asking: what factors of identification procedures result in higher than average identification rates of historically underrepresented gifted students? The theory guiding this study is Social Dominance Theory by Sidanius and Pratto (1999), which holds that possible oppression and discrimination is subconscious and upheld by society as a whole, whether or not it works in favor of society. This study focused on 3 elementary schools that have data that supports a higher than average enrollment of gifted students that are historically underrepresented. At each school interviews were conducted with 10 – 15 participants who have direct contact with the gifted program: principals, assistant principals, gifted coordinators, psychologists, counselors, and lead teachers. Data from the interviews were analyzed for categories and themes to connect important in this manner, and adds to the growing empirical research. Specific documents were analyzed for additional data

    Trypanosoma cruzi IIc: phylogenetic and phylogeographic insights from sequence and microsatellite analysis and potential impact on emergent Chagas disease.

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    Trypanosoma cruzi, the etiological agent of Chagas disease, is highly genetically diverse. Numerous lines of evidence point to the existence of six stable genetic lineages or DTUs: TcI, TcIIa, TcIIb, TcIIc, TcIId, and TcIIe. Molecular dating suggests that T. cruzi is likely to have been an endemic infection of neotropical mammalian fauna for many millions of years. Here we have applied a panel of 49 polymorphic microsatellite markers developed from the online T. cruzi genome to document genetic diversity among 53 isolates belonging to TcIIc, a lineage so far recorded almost exclusively in silvatic transmission cycles but increasingly a potential source of human infection. These data are complemented by parallel analysis of sequence variation in a fragment of the glucose-6-phosphate isomerase gene. New isolates confirm that TcIIc is associated with terrestrial transmission cycles and armadillo reservoir hosts, and demonstrate that TcIIc is far more widespread than previously thought, with a distribution at least from Western Venezuela to the Argentine Chaco. We show that TcIIc is truly a discrete T. cruzi lineage, that it could have an ancient origin and that diversity occurs within the terrestrial niche independently of the host species. We also show that spatial structure among TcIIc isolates from its principal host, the armadillo Dasypus novemcinctus, is greater than that among TcI from Didelphis spp. opossums and link this observation to differences in ecology of their respective niches. Homozygosity in TcIIc populations and some linkage indices indicate the possibility of recombination but cannot yet be effectively discriminated from a high genome-wide frequency of gene conversion. Finally, we suggest that the derived TcIIc population genetic data have a vital role in determining the origin of the epidemiologically important hybrid lineages TcIId and TcIIe

    Robust Virtual Sensing for Vehicle Agile Manoeuvring:A Tyre-model-less Approach

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    Relational Supervision: Jegnaship And Eldering As Emancipatory Pedagogy For Black Teacher Supervision

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    The case delves into the historical and cultural roots of African education, emphasizing the vital role of elders and community in the learning process. It examines the impact of African educational philosophies, particularly from the Nile and Niger river valleys, on the development of character, humanness, and spirituality. The case explores the adaptation of these philosophies by African people during the Middle Passage and their application in Western contexts for the supervision of African American teachers. By interweaving culture, history, education, and storytelling, the authors aim to highlight the unique contributions of African American educational experiences. They argue that these experiences provide valuable strategies for the liberation struggle and the transformation of Black teacher development. The case also explores contemporary issues in the teaching profession, such as the limited presence of African American educators, pedagogical negligence, and professional marginalization, proposing culturally-centered tools for community preservation and well-being. The central theme is the importance of relational supervision rooted in African and African American cultural knowledge, which is seen as key to nurturing Black novice teachers and fostering their professional development

    Diel Activity Patterns and Movement of Invasive Lionfish (Pterois volitans/P. miles) in the Florida Keys Identified Using Acoustic Telemetry

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    The invasion of Indo—Pacific lionfish (Pterois volitans/P. miles) throughout the Caribbean and southeastern U.S. Atlantic represents a significant ecological threat, yet few studies have examined the daily activity and movement patterns of this invasive species. In this study, passive acoustic telemetry was used to track lionfish at 4 coral reef sites in the Florida Keys. Fourteen lionfish were tagged among the 4 sites, and the total number of days tagged fish were detected ranged from 5 to 141 days. Hourly detection data revealed diel activity patterns with peaks at dawn and dusk. Mixed model analysis of detection data indicated a significant effect of time of day, with lionfish activity greater at twilight than during day or night. These results support observations from previous studies that lionfish are most active at dawn and dusk when they are foraging. The 95% kernel utilization distribution home range size ranged from 360–18,812 m2. Lionfish movements were generally localized, with mean daily distance moved ranging from 24–116 m, although one lionfish had a maximum daily distance moved of 427 m. Short—term activity centers revealed possible diel shifts in micro—habitat use for 2 lionfish, as well as an emigration of one lionfish to an adjacent patch reef ~200 m away. These findings increase our understanding of lionfish behavior on coral reefs and highlight the need for more detailed studies examining fine—scale habitat use and movements across more habitat types. The results from this study will further contribute to the spatial information required to improve the effectiveness of monitoring and controlling lionfish populations in the Florida Keys
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