670 research outputs found
Distribution of cogenetic iron and clay deposits in the central Appalachian region
Maps of more than 500 abandoned iron mines, 350 early iron furnaces, and numerous clay mines in the central part of the Appalachian region reveal the distribution and close association of siderite-limonite bearing ores and clay deposits. The deposits crop out from Lancaster County, Pennsylvania to Scioto County, Ohio, a distance of more than 300 miles. The geologic settings of the deposits are diverse. In the Valley and Ridge Province and Piedmont Province, mineralization follows structures such as major sub-horizontal thrust faults (e.g. Martic) and steep thrust faults, (e. g. Path Valley), that juxtapose carbonate units against other rocks. Carbonate units within the Plateau Province also contain economic deposits of iron ores and clay. The ores are commonly siderite and limonite principally in the form of nodules and other irregular masses in clayey, calcareous beds. Illite and kaolinite are the main clay minerals. Silica is a common constituent of the clayey rocks and in some of the iron-rich, ore horizons (e.g. Buhrstone). The working hypothesis for the formation of the iron ore and clay is that reactive fluids probably moved westward along structural and stratigraphic horizons in response to tectonic events and where they encounter carbonate rocks, clay formed and iron precipitated under favorable geochemical conditions. This hypothesis differs from other ideas such as weathering and consequent development of leached paleosols, and bog iron formation. Modern models of iron deposition are based on shallow groundwater transporting iron to the precipitation site. The possible outflow of basinal fluids along deep thrust faults and cross strike discontinuities was considered as an alternative process for iron deposition and clay formation
Practice Guidelines: Addressing Vestibular and Visual Problems in the Neurologically Impaired Adult
The visual and vestibular problems experienced by adults post brain injury (concussion, traumatic brain injury, cerebral vascular accident, tumor removal, etc.) must be evaluated and treated in conjunction with each other for best outcomes. The American Occupational Therapy Association’s (AOTA) Practice Framework categorizes both the visual and vestibular sensory systems as client factors (body functions) that are a part of the scope of practice of occupational therapy (AOTA, 2020). AOTA’s statement on vestibular impairment, vestibular rehabilitation, and occupational performance emphasizes the importance of occupational therapists addressing this critical client factor. The skills of entry-level and advanced-level occupational therapists are outlined in that document (AOTA, 2017). The objective of this article is to provide practical guidance to support advanced-level occupational therapists in more careful analysis of vestibulo-ocular skills that are needed for safe and efficient occupational performance. Literature and conceptual models from 1986 to 2021 from the fields of occupational therapy, physical therapy, ophthalmology, optometry, audiology, neurology, and otolaryngology that address the visual and vestibular problems experienced by adults with traumatic brain injury were reviewed and compared. Two models are presented to provide a framework to guide occupational therapy assessment and intervention of clients with neurological disorders who have vestibulo-ocular deficits that interfere with occupational performance
The Relationship Between A Kindergarten Screening Test And Other Measures
The purpose of this study is one of exploratory validation. Concurrent validity was established by showing the relationship between the experimental instrument and the Lee-Clark Reading Readiness Test. The relationships among the experimental instruments, the Lee-Clark Reading Readiness Test, kindergarten teacher judgment, and first grade post-readiness reading group placement determined the predictive validity. The statistics offered in this study are for descriptive rather than definitive purposes
Dual Heat Pulse, Dual Layer Thermal Protection System Sizing Analysis and Trade Studies for Human Mars Entry Descent and Landing
NASA has been recently updating design reference missions for the human exploration of Mars and evaluating the technology investments required to do so. The first of these started in January 2007 and developed the Mars Design Reference Architecture 5.0 (DRA5). As part of DRA5, Thermal Protection System (TPS) sizing analysis was performed on a mid L/D rigid aeroshell undergoing a dual heat pulse (aerocapture and atmospheric entry) trajectory. The DRA5 TPS subteam determined that using traditional monolithic ablator systems would be mass expensive. They proposed a new dual-layer TPS concept utilizing an ablator atop a low thermal conductivity insulative substrate to address the issue. Using existing thermal response models for an ablator and insulative tile, preliminary hand analysis of the dual layer concept at a few key heating points indicated that the concept showed potential to reduce TPS masses and warranted further study. In FY09, the followon Entry, Descent and Landing Systems Analysis (EDL-SA) project continued by focusing on Exploration-class cargo or crewed missions requiring 10 to 50 metric tons of landed payload. The TPS subteam advanced the preliminary dual-layer TPS analysis by developing a new process and updated TPS sizing code to rapidly evaluate mass-optimized, full body sizing for a dual layer TPS that is capable of dual heat pulse performance. This paper describes the process and presents the results of the EDL-SA FY09 dual-layer TPS analyses on the rigid mid L/D aeroshell. Additionally, several trade studies were conducted with the sizing code to evaluate the impact of various design factors, assumptions and margins
Changes in temperature and stem water content evoke erroneous sap flux density estimates with Thermal Dissipation Probes
Self-Reported Eating Disorder Risk in Lean and Non-Lean NCAA Collegiate Athletes
Purpose The purpose of this present study was to examine gender differences in overall scores on the Eating Attitudes Test (EAT-26) in National Collegiate Athletic Association (NCAA) college athletes in “lean” sports versus “non-lean” sports.
Methods Using a self-report survey design, this study examined eating disorder risk in 121 NCAA college athletes, using the EAT-26. We expected that female athletes and athletes in “lean” sports would report higher scores on the EAT-26.
Results There was a significant effect of sport type (lean vs. non-lean) on eating attitudes and behaviors, with those in non-lean sports reporting higher scores, on average, on the attitudinal measure and those in lean sports reporting, on average, higher scores on the behavioral measure. There was an interaction between gender and sport type (lean vs. non-lean) on eating attitudes and behaviors. Male athletes in non-lean sports had the highest overall average scores on the attitudinal portion of the EAT-26, and males in lean sports had the lowest scores. However, on the EAT-26 behavioral portion, men in lean sports reported significantly higher scores than did men in non-lean sports. Female athletes, regardless of sport type, reported similar scores on both the EAT- 26 attitudinal and behavioral sections.
Conclusions Our findings suggest that athletes, regardless of sport type and gender, may be affected by eating disorder symptomatology. Gender differences may be smaller in athletic populations than previously thought. Sport type may affect whether disordered eating symptomatology presents as attitudinal or behavioral in nature, especially in male athletes.
Level of evidence Descriptive study, Level V
Transport of root-derived CO2 via the transpiration stream affects aboveground tree physiology
Transport of dissolved CO2 in xylem sap and subsequent assimilation in Populus trees in the field
Effects of Stock Type and Fall Fertilization on Survival of Longleaf Pine Seedlings Planted in Lignite Minespoil
One-year-old longleaf pine (Pinus palustris Mill.) seedlings were hand-planted in January 1996 on an east Texas minespoil site. Effects of two seedling stock types and four levels of preplanting fall fertilization on seedling survival were evaluated. Fertilizer treatments consisting of a single application of ammonium nitrate (73 kilograms per hectare N), phosphorus (81 kilograms per hectare P), diammonium phosphate (73 kilograms per hectare N, 81 kilograms per hectare P), or control (no fertilizer) were applied to bare-root and container seedlings in November 1995. Root growth potential, the ability of a seedling to initiate and elongate new roots when placed into a favorable environment, was measured at time of planting. Field survival was surveyed monthly beginning in April 1996. Data were examined using analysis of variance. Container seedlings had significantly higher root growth potential and survival than bare-root. Fertilizer treatment effects, while not significant, tended to decrease both root growth potential and early survival for bare-root seedlings, and to increase root growth potential and decrease survival for container seedlings. Drought conditions during the 1996 growing season probably had a negative effect on survival of both bare-root and container seedlings. Only 2 percent of bare-root and 56 percent of container seedlings survived through the growing season, suggesting that only container stock should be used for reforestation of longleaf on minespoil sites. However, in years with normal precipitation, stock type effects on survival may not be significant and planting bare-root seedlings may be a viable option
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