3,129 research outputs found
Classroom and the Cloze Procedure: Interaction in Imagery
The paper will give the background research concerning cloze techniques, detail the steps teachers would follow to use Interactive Cloze, report behavioral observations within the classroom setting, and indicate direction for research into the efficacy of this procedure
The Use of Concept Formation Study Guides for Social Studies Reading Materials
No abstract available
Insulinlike Growth Factor 1- and 2-Augmented Collagen Gel Repair of Facial Osseous Defects
BACKGROUND: Defects of the facial bone structure are common problems for the facial plastic surgeon. Native type 1 collagen gels (T1CGs) have been shown to mediate repair of facial critical-size defects in rat models.
OBJECTIVE: To evaluate the efficacy of T1CG augmented with insulinlike growth factor (IGF) 1, IGF-2, and a combination of IGF-1 and IGF-2 on the repair of facial critical-size defects in a rodent model.
METHODS: Twenty-four retired male breeder Sprague-Dawley rats were divided into 4 groups of 6 animals. Facial critical-size defects were created by removing the nasalis bones with a bone-cutting drill. Defects were treated with 300 pg of type 1 collagen gel (T1CG), T1CG augmented with 3 microg of IGF-1, T1CG augmented with 3 microg of IGF-2, or T1CG augmented with a combination of 3 microg of IGF-1 and 3 microg of IGF-2. After 30 days the animals were examined at necropsy with precise planimetry, histological analysis of new bone growth, and radiodensitometric analysis of bone thickness.
RESULTS: Radiodensitometric measurements showed that IGF-2 augmentation resulted in greatest osseous healing, with measurements being statistically significant over those of all other groups (P\u3c or = .03). Combination IGF-1 and IGF-2 had osseous healing that was intermediate between IGF-1 augmentation and IGF-2 augmentation alone, with measurements being statistically significant over those of unaugmented gels (P
CONCLUSION: Collagen gels augmented with IGF significantly enhance the osteoconductive repair of nasal critical-size defects in a rodent model, with IGF-2 showing highest efficacy
Deciphering interactions between white-tailed deer and approaching vehicle
Deer-vehicle collisions are a major transportation hazard, but factors affecting deer escape decision-making in response to vehicle approach remain poorly characterized. We made opportunistic observations of deer response to vehicle approach during daylight hours on a restricted- access facility in Ohio, USA (vehicle speeds were ≤64 km/h). We hypothesized that animal proximity to the road, group size, vehicle approach, and ambient conditions would affect perceived risk by white-tailed deer (Odocoileus virginianus) to vehicle approach, as measured by flight-initiation distance (FID). We constructed a priori models for FID, as well as road-crossing behavior. Deer responses were variable and did not demonstrate spatial or temporal margins of safety. Road-crossing behavior was slightly and positively influenced by group size during winter. Deer showed greater FIDs and likelihood of crossing when approached in the road; directionality of approach likely increased the perceived risk. These findings are consistent with antipredator theory relative to predator approach direction
Radiation Single Event Effects (SEE) Impact on Complex Avionics Architecture Reliability
The NASA Engineering and Safety Center (NESC) has an urgent need to understand how system-level reliability of an avionics architecture is compromised when portions of the architecture are temporarily unavailable due to single event effects (SEE). The proposed activity parametrically evaluated these SEE impacts on system reliability based on mission duration, upset rate and recovery times for a representative redundant architecture. The key stakeholders for this study are NASA programs and projects that expect to use avionics architectures with electrical, electronic and electromechanical (EEE) parts susceptible to SEE when exposed to the mission expected radiation environment
Improving animal monitoring using small unmanned aircraft systems (sUAS) and deep learning networks
In recent years, small unmanned aircraft systems (sUAS) have been used widely to monitor animals because of their customizability, ease of operating, ability to access difficult to navigate places, and potential to minimize disturbance to animals. Automatic identification and classification of animals through images acquired using a sUAS may solve critical problems such as monitoring large areas with high vehicle traffic for animals to prevent collisions, such as animal-aircraft collisions on airports. In this research we demonstrate automated identification of four animal species using deep learning animal classification models trained on sUAS collected images. We used a sUAS mounted with visible spectrum cameras to capture 1288 images of four different animal species: cattle (Bos taurus), horses (Equus caballus), Canada Geese (Branta canadensis), and white-tailed deer (Odocoileus virginianus). We chose these animals because they were readily accessible and whitetailed deer and Canada Geese are considered aviation hazards, as well as being easily identifiable within aerial imagery. A four-class classification problem involving these species was developed from the acquired data using deep learning neural networks. We studied the performance of two deep neural network models, convolutional neural networks (CNN) and deep residual networks (ResNet). Results indicate that the ResNet model with 18 layers, ResNet 18, may be an effective algorithm at classifying between animals while using a relatively small number of training samples. The best ResNet architecture produced a 99.18% overall accuracy (OA) in animal identification and a Kappa statistic of 0.98. The highest OA and Kappa produced by CNN were 84.55% and 0.79 respectively. These findings suggest that ResNet is effective at distinguishing among the four species tested and shows promise for classifying larger datasets of more diverse animals
Loosen Control Without Losing Control. Formalisation and Decentralisation within Commons-Based Peer Production
This study considers commons-based peer production (CBPP) by examining the organizational processes of the free/libre open-source software community, Drupal. It does so by exploring the sociotechnical systems that have emerged around both Drupal's development and its face-to-face communitarian events. There has been criticism of the simplistic nature of previous research into free software; this study addresses this by linking studies of CBPP with a qualitative study of Drupal's organizational processes. It focuses on the evolution of organizational structures, identifying the intertwined dynamics of formalization and decentralization, resulting in coexisting sociotechnical systems that vary in their degrees of organicity
Targeting deforestation rates in climate change policy: a "Preservation Pathway" approach
We present a new methodological approach to incorporating deforestation within the international climate change negotiating regime. The approach, called "Preservation Pathway" combines the desire for forest preservation with the need to reduce emissions associated with forest loss by focusing on the relative rate of change of forest cover as the criteria by which countries gain access to trading preserved forest carbon stocks. This approach avoids the technically challenging task of quantifying historical or future deforestation emission baselines. Rather, it places emphasis on improving quantification of contemporary stocks and the relative decline in deforestation rates necessary to preserve those stocks. This approach places emphasis on the complete emissions trajectory necessary to attain an agreed-upon preserved forest and as such, meets both forest conservation and climate goals simultaneously
X-ray and optical monitoring of the peculiar source 4U 1700+24/V934 Her
(Abridged) We report on ASCA and BeppoSAX observations of the X-ray source 4U
1700+24 and on (quasi-)simultaneous spectroscopy of its optical counterpart,
V934 Her, from the Loiano 1.5-meter telescope. Archival ROSAT and RXTE data as
well as the RXTE ASM light curve of 4U 1700+24 are also analyzed along with a
1985 EXOSAT pointing. The optical spectra are typical of a M2 III star; a
revised distance to the object of ~400 pc is inferred. While these spectra do
not show either any change between the two epochs or any peculiar feature, the
X-ray spectra reveal a complex and long-term variable shape, with a clear soft
excess. The X-ray spectral properties of the source are best described by a
thermal Comptonization spectrum plus a soft energy(<1 keV) excess, which can be
modeled with a blackbody emission with kT_BB ~ 1 keV; the latter component is
not detected at the lowest source flux levels. The ratio between the two
components varies substantially with the source flux. The X-ray emission from
the object appears to become harder as its luminosity increases, and the RXTE
data acquired during an outburst occurred during Fall 1997 display a hard tail
detected up to 100 keV. Apart from erratic shot-noise variability on timescales
of tens to thousands of seconds, no significant pulsations or QPOs are found
from the timing analysis of the X-ray light curves. With the new distance
determination, the 2-10 keV X-ray luminosity range spanned in the considered
observations lies between ~2x10^32 and ~1x10^34 erg/s. All this allows us to
suggest a scenario consisting of a wide binary system in which a neutron star
accretes matter from the wind of an M giant.Comment: 14 pages, 5 figures, to be published on Astronomy & Astrophysics,
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