451 research outputs found
Crop Nutrient Considerations for Wet or Flooded Fields
Many South Dakota fields have standing water with saturated soil conditions this spring. These wet soil conditions can have implications for existing soil nutrients and for nutrients applied for this season
Monitoring strip mining and reclamation with LANDSAT data in Belmont County, Ohio
The utility of LANDSAT digital data for mapping and monitoring surface mines in Belmont County, Ohio was investigated. Two data sets from 1976 and 1979 were processed to classify level 1 land covers and three strip mine categories in order to examine change over time and assess reclamation efforts. The two classifications were compared with aerial photographs. Results of the accuracy assessment show that both classifications are approximately 86 per cent correct, and that surface mine change detection (date-to-date comparison) is facilitated by the digital format of LANDSAT data
A Study of Feature Extraction Using Divergence Analysis of Texture Features
An empirical study of texture analysis for feature extraction and classification of high spatial resolution remotely sensed imagery (10 meters) is presented in terms of specific land cover types. The principal method examined is the use of spatial gray tone dependence (SGTD). The SGTD method reduces the gray levels within a moving window into a two-dimensional spatial gray tone dependence matrix which can be interpreted as a probability matrix of gray tone pairs. Haralick et al (1973) used a number of information theory measures to extract texture features from these matrices, including angular second moment (inertia), correlation, entropy, homogeneity, and energy. The derivation of the SGTD matrix is a function of: (1) the number of gray tones in an image; (2) the angle along which the frequency of SGTD is calculated; (3) the size of the moving window; and (4) the distance between gray tone pairs. The first three parameters were varied and tested on a 10 meter resolution panchromatic image of Maryville, Tennessee using the five SGTD measures. A transformed divergence measure was used to determine the statistical separability between four land cover categories forest, new residential, old residential, and industrial for each variation in texture parameters
Real Time Fatigue Damage Growth Assessment of a Composite Three-Stringer Panel Using Passive Thermography
Fatigue testing of advanced composite structures is critical to validate both structural designs and damage prediction models. In-situ inspection methods are necessary to track damage onset and growth as a function of load cycles. Passive thermography is a large area, noncontact inspection technique that is used to detect composite damage onset and growth in real time as a function of fatigue cycles. The thermal images are acquired in synchronicity to the applied compressive load using a dual infrared camera acquisition system for full (front and back) coverage. Image processing algorithms are investigated to increase defect contrast areas. The thermal results are compared to non-immersion ultrasound inspections and acoustic emission data
Wireless earbuds for low-cost hearing screening
We present the first wireless earbud hardware that can perform hearing
screening by detecting otoacoustic emissions. The conventional wisdom has been
that detecting otoacoustic emissions, which are the faint sounds generated by
the cochlea, requires sensitive and expensive acoustic hardware. Thus, medical
devices for hearing screening cost thousands of dollars and are inaccessible in
low and middle income countries. We show that by designing wireless earbuds
using low-cost acoustic hardware and combining them with wireless sensing
algorithms, we can reliably identify otoacoustic emissions and perform hearing
screening. Our algorithms combine frequency modulated chirps with wideband
pulses emitted from a low-cost speaker to reliably separate otoacoustic
emissions from in-ear reflections and echoes. We conducted a clinical study
with 50 ears across two healthcare sites. Our study shows that the low-cost
earbuds detect hearing loss with 100% sensitivity and 89.7% specificity, which
is comparable to the performance of a $8000 medical device. By developing
low-cost and open-source wearable technology, our work may help address global
health inequities in hearing screening by democratizing these medical devices
Thermography Inspection for Early Detection of Composite Damage in Structures During Fatigue Loading
Advanced composite structures are commonly tested under controlled loading. Understanding the initiation and progression of composite damage under load is critical for validating design concepts and structural analysis tools. Thermal nondestructive evaluation (NDE) is used to detect and characterize damage in composite structures during fatigue loading. A difference image processing algorithm is demonstrated to enhance damage detection and characterization by removing thermal variations not associated with defects. In addition, a one-dimensional multilayered thermal model is used to characterize damage. Lastly, the thermography results are compared to other inspections such as non-immersion ultrasonic inspections and computed tomography X-ray
A clinical pathway for the postoperative management of hypocalcemia after pediatric thyroidectomy reduces blood draws
Objectives
Postoperative calcium management is challenging following pediatric thyroidectomy given potential limitations in self-reporting symptoms and compliance with phlebotomy. A protocol was created at our tertiary children's institution utilizing intraoperative parathyroid hormone (PTH) levels to guide electrolyte management during hospitalization.
The objective of this study was to determine the effect of a new thyroidectomy postoperative management protocol on two primary outcomes: (1) the number of postoperative calcium blood draws and (2) the length of hospital stay.
Study design
Institutional review board approved retrospective study (2010–2016).
Methods
Consecutive pediatric total thyroidectomy and completion thyroidectomy ± neck dissection cases from 1/1/2010 through 8/5/2016 at a single tertiary children's institution were retrospectively reviewed before and after initiation of a new management protocol. All cases after 2/1/2014 comprised the experimental group (post-protocol implementation). The pre-protocol control group consisted of cases prior to 2/1/2014. Multivariable linear and Poisson regression models were used to compare the control and experimental groups for outcome measure of number of calcium lab draws and hospital length of stay.
Results
53 patients were included (n = 23, control group; n = 30 experimental group). The median age was 15 years. 41 patients (77.4%) were female. Postoperative calcium draws decreased from a mean of 5.2 to 3.6 per day post-protocol implementation (Rate Ratio = 0.70, p < .001), adjusting for covariates. The mean number of total inpatient calcium draws before protocol initiation was 13.3 (±13.20) compared to 7.2 (±4.25) in the post-protocol implementation group. Length of stay was 2.1 days in the control group and 1.8 days post-protocol implementation (p = .29). Patients who underwent concurrent neck dissection had a longer mean length of stay of 2.32 days compared to 1.66 days in those patients who did not undergo a neck dissection (p = .02). Hypocalcemia was also associated with a longer mean length of stay of 2.41 days compared to 1.60 days in patients who did not develop hypocalcemia (p < .01).
Conclusions
The number of calcium blood draws was significantly reduced after introduction of a standardized protocol based on intraoperative PTH levels. The hospital length of stay did not change. Adoption of a standardized postoperative protocol based on intraoperative PTH levels may reduce the number of blood draws in children undergoing thyroidectomy
Light Weight Silicon Mirrors for Space Instrumentation
Each mirror is a monolithic structure from a single crystal of silicon. The mirrors are light weighted after the optical surface is ground and polished. Mirrors made during the initial phase of this work were typically 1/50 lambda or better (RMS at 633 n m
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