16,444 research outputs found
Evaluation of Nearshore Carbonate Chemistry Within Major Navigational Inlets of the Kristin Jacobs Coral Reef Ecosystem Conservation Area
The absorption of atmospheric carbon dioxide (CO2) by ocean surface water is causing ocean acidification (OA), a process by which the reaction between water and CO2 changes ocean carbonate chemistry. Predictions of OA trajectories modeled by the Intergovernmental Panel on Climate Change (IPCC) are based on open ocean trends and may not accurately predict changes to variable nearshore ecosystems. The dynamic nature of nearshore ocean chemistry, and prevalence of OA vulnerable species within these ecosystems complicates the process of making accurate OA impact predictions within the coastal zone. Florida’s coral reef is a nearshore ecosystem vulnerable to the effects of OA, as water chemistry along the east coast of Florida is influenced by the anthropogenically polluted and environmentally modified effluent carried out of its nearby inlets and waterways. Field samples collected during this study provide spatiotemporal data from 9 navigational inlets and five wastewater outfalls affecting the nearshore carbonate chemistry dynamics of the Kristin Jacobs Coral Ecosystem Conservation Area (Coral ECA) over the course of a year. Several notable trends were identified involving the carbonate system and associated environmental conditions. The concentrations of solutes in the freshwater endmembers were predicted through linear regressions with salinity and indicate that all inlets and outfalls within our sample region export greater amounts of inorganic carbon compared to alkalinity. The low ratio of alkalinity to dissolved inorganic carbon indicate that freshwater mixing could exacerbate ocean acidification in the nearshore coasts of South Florida. Furthermore, there was a trend between biogeochemical properties of the inlets with latitude, indicating diverse drivers of carbonate chemistry related to fundamental differences in the freshwater inputs along the coast. These results are intended to inform local and regional environmental management strategies with current and accurate carbonate chemistry measurements and may serve as environmental baselines by which future impact assessments may compare against
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Open windrow composting of polymers: An investigation into the rate of degradation of polyethylene
The compostability of degradable polymers under open windrow composting conditions is explored within this paper. Areas for consideration were the use of, and impacts of, degradable polyethylene (PE) sacks on the composting process and the quality of the finished compost product. These factors were investigated through polymer weight loss over the composting process, the amount of polymer residue and chemical contaminants in the finished compost product, the windrow temperature profiles and a bioassay to establish plant growth and germination levels using the final compost product. This trial also included a comparative study of the weight loss under composting conditions of two different types of ‘degradable’ polymer sacks currently on the European market: PE and a starch based product. Statistical analysis of the windrow temperature profiles has led to the development of a model, which can help to predict the expected trends in the temperature profiles of open compost windrows where the organic waste is kerbside collected using a degradable PE sack
Toward a More Efficient and Effective Method for Tracking 3D Bone Position and Orientation in Fluoroscopic Images
Osteoarthritis (OA) is the primary cause of mobility-based disability in the United States. Approximately 12% of osteoarthritis cases occur following traumatic injury, through a process termed post-traumatic osteoarthritis (PTOA). PTOA accelerates the degeneration of articular cartilage, thus having profound effects, particularly on the young athletic population. It has been found that, following injury, there are both biological changes to the articulating cartilage as well as dynamic changes to the knee joint kinematics. However, it remains unclear how these changes in kinematics correlate with cartilage degradation. Understanding this relationship of the mechanisms that lead to PTOA assists in the development of effective treatments for patients who have suffered previous knee injuries. In order for researchers to be best equipped to observe and understand how altered kinematics following surgery result in cartilage degradation, new methods must be developed to quantify these changes to the kinematics. Two of the leading methods for measuring bone movement and studying knee joint mechanics are motion capture and dual fluoroscopy with model-based tracking (DF-MBT). The primary problems with these methods are that motion capture, while providing near immediate results, is relatively inaccurate since it suffers from soft tissue artifact. DF-MBT, on the other hand, is considered accurate to within a millimeter, but proper post-processing of the data requires a significant amount of time. Ideally, there would be a method that provided results as accurately as the DF-MBT method in the time interval of the motion capture method. Therefore, the purpose of this study was to develop a tracking method that is faster than DF-MBT and accurate on the order of a millimeter or less. The initial methodology behind achieving this goal was to write a code that would produce a transformation matrix between the DF-MBT and motion capture pose maps. A pose map is a representation of the position (pose) of an object in reference to a particular coordinate system at each frame. Therefore, a static frame could be used in order to define a transformation from motion capture clusters to the bone\u27s location. This transformation matrix can then be applied to the dynamic frames to produce results on the same level of accuracy in a much shorter time frame. This study analyzed and compared the results of three different methods of measuring bone movement; traditional DF-MBT tracking (Model Based Tracking), the previously described pose map method (Skin Marker Tracking), and an additional method which combined the process of the other two methods (Combined Tracking). Despite the Skin Marker Method providing unsatisfactory results, the goal of producing a more efficient and effective method for measuring bone movement was still achieved. The Combined Tracking method, which involved using the transformation code as a starting point for traditional DF-MBT alignment, resulted in more accurate results than DF-MBT in a shorter time frame. Therefore, a more efficient and effective method for tracking 3D bone position and orientation in fluoroscopic imaging was successfully developed
How does the Hubble Sphere limit our view of the Universe?
It has recently been claimed that the Hubble Sphere represents a previously
unknown limit to our view of the universe, with light we detect today coming
from a proper distance less than this "Cosmic Horizon" at the present time. By
considering the paths of light rays in several cosmologies, we show that this
claim is not generally true. In particular, in cosmologies dominated by phantom
energy (with an equation of state of \omega < -1) the proper distance to the
Hubble Sphere decreases, and light rays can cross it more than once in both
directions; such behaviour further diminishes the claim that the Hubble Sphere
is a fundamental, but unrecognised, horizon in the universe.Comment: 4 pages, 4 figures: Accepted for publication in Monthly Notices of
the Royal Astronomical Society Letter
Vicarious Trauma Exposure and Its Effects on Mental Health among Adolescents and Adults: A Narrative Research Review
Vicarious Trauma Exposure and Its Effects on Mental Health among Adolescents and Adults: A Narrative Research Review
Harris Davis, Dept. of Psychology, Angel Whitfield, Sydney Judge, Bailee Beverly, Jenna Minter, Harrison Davis, and Eryn DeLaney and Chloe Walker, Dept. of Psychology Graduate Students, with Dr. Chelsea Williams, Dept. of Psychology
A narrative research review was conducted to examine studies that have tested the relation between vicarious trauma (i.e., witnessing abuse of others; Trautmann, S., Reineboth, M., Trikojat, K., Richter, J., Hagenaars, M. A., Kanske, P., & Schäfer, J. (2018). and mental health in adolescents and young adults. Using psycinfo to find research conducted to date, this review indicated that there are various types of trauma that adolescents might be exposed to (e.g., domestic abuse, emotional abuse, and physical abuse) and various forms of mental health issues (e.g., post traumatic stress disorder, depression, and anxiety) that might result from such trauma. (Erolin, K. S., Wieling, E., & Parra, R. E. A. (2014)., , Stowkowy, J., Goldstein, B. I., MacQueen, G., Wang, J., Kennedy, S. H., Bray, S., Lebel, C., & Addington, J. (2020). Findings from this review also suggest that there is a relation between varying types of traumatic exposure and several types of depressive symptoms (Monfort, E., Afzali M. H. (2015), Merza, K., Papp, G., & Szabó, I. K. (2015) and that there are more studies on adults than on adolescents. These effects will be discussed. Gaps in the literature will be referenced and potential future research directions will be acknowledged. In conclusion, this narrative research review emphasizes the importance of knowing the effects of vicarious trauma on adolescents and adults for preventative purposes.https://scholarscompass.vcu.edu/uresposters/1336/thumbnail.jp
Human Factors of Flight-deck Automation: NASA/Industry Workshop
The scope of automation, the benefits of automation, and automation-induced problems were discussed at a workshop held to determine whether those functions previously performed manually on the flight deck of commercial aircraft should always be automated in view of various human factors. Issues which require research for resolution were identified. The research questions developed are presented
On the philosophy of modeling—reply to a comment by M. R. DroopX
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110088/1/lno19782320385.pd
Seasonal Minimum and Maximum Solar Ultraviolet Exposure Measurements of Classroom Teachers Residing in Tropical North Queensland, Australia
The risk of keratinocyte skin cancer, malignant melanoma and ultraviolet radiation (UVR)-induced eye disease is disproportionately higher in Australia and New Zealand compared to equivalent northern hemisphere latitudes. While many teachers are aware of the importance of reinforcing sun-safety messages to students, many may not be aware of the considerable personal exposure risk while performing outdoor duties in locations experiencing high to extreme ambient-UVR year-round. Personal erythemally-effective exposure of classroom teachers in tropical Townsville (19.3o S) was measured to establish seasonal extremes in exposure behavior. Mean daily personal exposure was higher in winter (91.2 J m 2, 0.91 Standard Erythema Dose (SED)) than summer (63.3 J m-2, 0.63 SED). The range of exposures represent personal exposures that approximate current national guidelines for Australian workers at the study latitude of approximately 1.2 SED (30 J m-2 effective to the International Commission on Non-Ionizing Radiation Protection). Similar proportions of teachers spent more than 1 hour outdoors per day in winter (28.6%) and summer (23.6%) as part of their teaching duties with seasonal differences having little effect on the time of exposure. Personal exposures for teachers peaked during both seasons near school meal-break times at 11:00 am and 1:00 pm respectively
Better Analysis by Analogy: Applying Data Modeling Techniques to Grounded Theory
When done well, grounded theory is an excellent qualitative research tool for explaining new or complex phenomena. Still, grounded theory is interpretative in nature, raising questions about the levels of reliability and validity in grounded theory studies. This paper argues that since grounded theory analysis methods are analogous to conceptual data modeling methods, data modeling techniques may be employed to enhance the validity and reliability of grounded theory research
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