Case 11-2016 Schwartz, Kevin R; El Saleeby, Chadi M; Nimkin, Katherine ...
The New England journal of medicine,
04/2016, Letnik:
374, Številka:
15
Journal Article
Recenzirano
A 12-year-old boy presented with a 1-month history of fever and abdominal pain. Three months earlier, he had traveled to the Dominican Republic. Laboratory evaluation revealed anemia and an elevated ...C-reactive protein level. Diagnostic tests were performed.
Presentation of Case
Dr. Katherine L. Tuttle
(Pediatrics): A 12-year-old boy was admitted to this hospital because of malaise, fevers, abdominal pain, and worsening pallor.
The patient had been well until 1 month before admission, when headache and abdominal pain developed. Examination by a school nurse revealed a temperature of 38.6°C and pale skin. A diagnosis of a viral illness was made, and follow-up with his pediatrician was recommended. When the patient was reexamined by the nurse 4 days later, the temperature was normal. The skin was pale, the pharynx was slightly erythematous, and the abdomen was tender. At follow-up . . .
Mutual information is a measure of the dependence between random variables that has been used successfully in myriad applications in many fields. Generalized mutual information measures that go ...beyond classical Shannon mutual information have also received much interest in these applications. We derive the mean squared error convergence rates of kernel density-based plug-in estimators of general mutual information measures between two multidimensional random variables <inline-formula> <tex-math notation="LaTeX">\mathbf {X} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">\mathbf {Y} </tex-math></inline-formula> for two cases: 1) <inline-formula> <tex-math notation="LaTeX">\mathbf {X} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">\mathbf {Y} </tex-math></inline-formula> are continuous; 2) <inline-formula> <tex-math notation="LaTeX">\mathbf {X} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">\mathbf {Y} </tex-math></inline-formula> may have a mixture of discrete and continuous components. Using the derived rates, we propose an ensemble estimator of these information measures called GENIE by taking a weighted sum of the plug-in estimators with varied bandwidths. The resulting ensemble estimators achieve the <inline-formula> <tex-math notation="LaTeX">1/N </tex-math></inline-formula> parametric mean squared error convergence rate when the conditional densities of the continuous variables are sufficiently smooth. To the best of our knowledge, this is the first nonparametric mutual information estimator known to achieve the parametric convergence rate for the mixture case, which frequently arises in applications (e.g. variable selection in classification). The estimator is simple to implement and it uses the solution to an offline convex optimization problem and simple plug-in estimators. A central limit theorem is also derived for the ensemble estimators and minimax rates are derived for the continuous case. We demonstrate the ensemble estimator for the mixed case on simulated data and apply the proposed estimator to analyze gene relationships in single cell data.
Image patch analysis of sunspots and active regions Moon, Kevin R.; Li, Jimmy J.; Delouille, Véronique ...
Journal of space weather and space climate,
2016, 20160101, 2016-01-01, Letnik:
6
Journal Article
Recenzirano
Odprti dostop
Context. The flare productivity of an active region is observed to be related to its spatial complexity. Mount Wilson or McIntosh sunspot classifications measure such complexity but in a categorical ...way, and may therefore not use all the information present in the observations. Moreover, such categorical schemes hinder a systematic study of an active region’s evolution for example. Aims. We propose fine-scale quantitative descriptors for an active region’s complexity and relate them to the Mount Wilson classification. We analyze the local correlation structure within continuum and magnetogram data, as well as the cross-correlation between continuum and magnetogram data. Methods. We compute the intrinsic dimension, partial correlation, and canonical correlation analysis (CCA) of image patches of continuum and magnetogram active region images taken from the SOHO-MDI instrument. We use masks of sunspots derived from continuum as well as larger masks of magnetic active regions derived from magnetogram to analyze separately the core part of an active region from its surrounding part. Results. We find relationships between the complexity of an active region as measured by its Mount Wilson classification and the intrinsic dimension of its image patches. Partial correlation patterns exhibit approximately a third-order Markov structure. CCA reveals different patterns of correlation between continuum and magnetogram within the sunspots and in the region surrounding the sunspots. Conclusions. Intrinsic dimension has the potential to distinguish simple from complex active regions. These results also pave the way for patch-based dictionary learning with a view toward automatic clustering of active regions.
An overview of the oyster industry in the US shows that oyster grading occurs at harvest, wholesale, and processing markets. Currently whole oysters, also called shellstock, are graded manually by ...screening and sorting based on diameter or weight, which does not concern shape appearance. However, studies show that customers prefer oysters that are round and 2
in. in diameter. This paper presents a simple and accurate shape analysis method for size and shape-based oyster grading. The proposed algorithm is currently programmed to perform shape analysis to grade oysters into good quality, banana, and irregular grades and can be extended to accommodate other grades acceptable for market. Other shape categories can be added with a simple configuration procedure. The contour of the oyster is extracted and its data points are reduced to 50 points using either curve evolution and fixed interval sub-sampling data reduction methods. A simple and accurate shape similarity measure method called turn angle cross-correlation (TAC) is developed to categorize oyster shell shape and other similar applications. Experimental result shows that this method performs well and is suitable for commercial use.
Image patch analysis of sunspots and active regions Moon, Kevin R.; Delouille, Véronique; Li, Jimmy J. ...
Journal of space weather and space climate,
2016, 20160101, 2016-01-01, Letnik:
6
Journal Article
Recenzirano
Odprti dostop
Context. Separating active regions that are quiet from potentially eruptive ones is a key issue in Space Weather applications. Traditional classification schemes such as Mount Wilson and McIntosh ...have been effective in relating an active region large scale magnetic configuration to its ability to produce eruptive events. However, their qualitative nature prevents systematic studies of an active region’s evolution for example. Aims. We introduce a new clustering of active regions that is based on the local geometry observed in Line of Sight magnetogram and continuum images. Methods. We use a reduced-dimension representation of an active region that is obtained by factoring the corresponding data matrix comprised of local image patches. Two factorizations can be compared via the definition of appropriate metrics on the resulting factors. The distances obtained from these metrics are then used to cluster the active regions. Results. We find that these metrics result in natural clusterings of active regions. The clusterings are related to large scale descriptors of an active region such as its size, its local magnetic field distribution, and its complexity as measured by the Mount Wilson classification scheme. We also find that including data focused on the neutral line of an active region can result in an increased correspondence between our clustering results and other active region descriptors such as the Mount Wilson classifications and the R-value. Conclusions. Matrix factorization of image patches is a promising new way of characterizing active regions. We provide some recommendations for which metrics, matrix factorization techniques, and regions of interest to use to study active regions.
Gps-Denied Navigation Using Sar Images And Neural Networks White, Teresa; Wheeler, Jesse; Lindstrom, Colton ...
ICASSP 2021 - 2021 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP),
2021-June-6
Conference Proceeding
Odprti dostop
Unmanned aerial vehicles (UAV) often rely on GPS for navigation. GPS signals, however, are very low in power and easily jammed or otherwise disrupted. This paper presents a method for determining the ...navigation errors present at the beginning of a GPS-denied period utilizing data from a synthetic aperture radar (SAR) system. This is accomplished by comparing an online-generated SAR image with a reference image obtained a priori. The distortions relative to the reference image are learned and exploited with a convolutional neural network to recover the initial navigational errors, which can be used to recover the true flight trajectory throughout the synthetic aperture. The proposed neural network approach is able to learn to predict the initial errors on both simulated and real SAR image data.
Postlaunch calibration of satellite-borne scatterometers using backscatter data from natural land targets helps to maintain scatterometer accuracy. Due to its temporal stability, the dry-snow zone of ...the Greenland ice sheet has been proposed in previous studies as a calibration target. Using QuikSCAT data, this letter examines the backscatter properties of the dry-snow zone that are relevant to Ku-band scatterometer calibration including temporal and spatial variabilities, and azimuth-angle and polarization and incidence-angle dependences. The backscatter is found to seasonally vary throughout the dry-snow zone by 0.4 dB on average. Small interannual variations (less than 1.5 dB over a nine year period) in the backscatter are also present in some regions. Azimuth modulation is generally less than 0.4 dB in magnitude and is not significant in some regions of the dry-snow zone. Melting and refreezing appear to cause the quasi-polarization ratio to temporarily decrease. Spatially consistent and relatively temporally stable regions that are well within the interior of the dry-snow zone are best suited as calibration sites.
The densities of eutectic (LiF)2–BeF2 and mixtures of this salt (FLiBe) with LaF3 were measured by dilatometry and by neutron attenuation from 673 K to 1,073 K. Because LaF3 has a limited solubility ...in FLiBe, it was necessary to determine the amount of LaF3 in solution before the density could be determined. The FLiBe density determination was favorably benchmarked against the literature data. A simple comparison was not available for the LaF3–FLiBe mixtures, so extrapolation of published data was necessary based on analysis using the Molten Salt Thermal Properties Database-Thermochemistry, or MSTDB-TC, developed by the US Department of Energy. Solubilities for LaF3 in FLiBe ranged from 1 to 4 mol % over 673 to 1,073 K. The salt system was heated and cooled over 24 h to evaluate potential changes in composition and hysteresis during the measurement. Changes in the meniscus were observed, and these were included in the correction for density determinations. Salt surface tension may have led to supersaturation of LaF3 in the salt because the solubility curve was nonlinear with respect to the inverse temperature, as would be expected for an ideal system. Surface tension measurements are currently underway to test this hypothesis.
Purpose This study tested hyperbaric oxygen (HBO) as an adjunct to surgery and antibiotics in the treatment of bisphosphonate-related osteonecrosis of the jaw (ONJ) and evaluated its effects on ...gingival healing, pain, and quality of life. Materials and Methods The investigators implemented a randomized controlled trial and enrolled a sample composed of patients with ONJ, where the predictor variable was HBO administered at 2 atm twice a day for 40 treatments as an adjunct to conventional therapy of surgery and antibiotics versus conventional therapy alone. Over the next 24 months, oral lesion size and number, pain, and quality of life were assessed. Results Forty-six patients (mean age, 66 yrs; 57% women) contributed data to the trial. There were no statistically significant differences in the distribution of variables used to assess randomization success between the HBO and standard treatment groups. Seventeen of 25 HBO-treated patients (68%) improved versus 8 of 21 controls (38.1%; P = .043, χ2 test). Mean time to improvement was 39.7 weeks (95% confidence interval CI, 22.4 to 57.0 weeks) for HBO-treated patients versus 67.9 weeks (95 CI, 48.4 to 87.5 weeks) for controls ( P = .03, log-rank test). However, complete gingival healing occurred in only 14 of 25 HBO-treated patients (52%) versus 7 of 21 controls (33.3%; P = .203, χ2 test), and time to healing was 59 weeks (95% CI, 42.8% to 75.8%) for HBO-treated patients versus 70 weeks (95 CI, 52.2% to 88.36%) for controls ( P = .32, log-rank test). Pain decreased faster for HBO-treated subjects ( P < .01, linear regression). Quality-of-life scores for physical health ( P = .002) and perceived health ( P = .043) decreased at 6 months for control group but for not the HBO group. Conclusions ONJ is multifactorial and no single treatment modality is likely to reverse it; however, it is treatable and even advanced presentations can improve with intensive multimodal therapy. Clinically, HBO appears to be a useful adjunct to ONJ treatment, particularly for more severe cases, although this study was underpowered to fully support this claim.
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