188 research outputs found
A Statistical, Data-driven Assessment of Climate Extremes and Trends for the Continental U.S.
Climate extremes are meteorological events that can have significant impacts on human and natural systems. Weather hazards, such as heat waves, drought, heavy thunderstorms, floods, hurricanes, occur frequently, and are a threat to human lives and property. Climate data observations spanning over 100 years are an important asset in understanding climate extremes and trends. This research uses daily climate data observations from more than 3000 climate stations in the continental U.S. to assess the climate trends and extremes, including temperature, precipitation, and snowfall. The climate data measurement sites were grouped by climate divisions and each climate division was statistically assessed for the following elements: maximum and minimum temperature, precipitation and snowfall. Furthermore, by dividing the climate data time series into 2 time intervals (1946-1980 and 1981-2015). Application of a host of non-parametric, statistical tests, provided insights on whether the recent time period is experiencing increased, decreased or similar frequencies of the climate extremes threshold being analyzed. The study also analyzed trends of climate extremes on a regional basis by breaking up the continental US into western, high plains, southern, midwestern, northeast and southeast regions. A data visualization system was also developed to assess and analyze the results from this data-intensive study. The visualization system includes intuitive choropleth maps and charts that depict climate trends
Evaluation of Frother Types for Improved Flotation Recovery and Selectivity
A laboratory study was conducted to evaluate and compare the effectiveness of nine different frother types when used in a three-phase, continuously operating froth flotation system. The frothers included several that are commonly used in the industry (e.g., MIBC, 2EH, and F-1) as well as unique frother types (e.g., F-3). The tests were conducted in a 5-cm diameter laboratory flotation column that provided near plug-flow mixing conditions due to a length-to-diameter ratio of around 50:1. Test results indicate that F-1, MIBC, and MPC (in order of decreasing effectiveness) provided the weakest performance in terms of combustible recovery while F-2, MAC, and 2EH were the top three generating the highest separation efficiencies. When processing ultrafine coal, the ash content of the flotation concentrate ranged from 10% to 15% while recovering over 80% of the combustible material. F-3, F-4, and DIBC provided over 80% recovery of combustibles at the expense in the amount of hydraulic entrainment. The flotation performances were also closely examined in accordance with the fundamental properties of the nine tested frothers, and their correlations were addressed in detail
Unsupervised Visible-Infrared Person ReID by Collaborative Learning with Neighbor-Guided Label Refinement
Unsupervised learning visible-infrared person re-identification (USL-VI-ReID)
aims at learning modality-invariant features from unlabeled cross-modality
dataset, which is crucial for practical applications in video surveillance
systems. The key to essentially address the USL-VI-ReID task is to solve the
cross-modality data association problem for further heterogeneous joint
learning. To address this issue, we propose a Dual Optimal Transport Label
Assignment (DOTLA) framework to simultaneously assign the generated labels from
one modality to its counterpart modality. The proposed DOTLA mechanism
formulates a mutual reinforcement and efficient solution to cross-modality data
association, which could effectively reduce the side-effects of some
insufficient and noisy label associations. Besides, we further propose a
cross-modality neighbor consistency guided label refinement and regularization
module, to eliminate the negative effects brought by the inaccurate supervised
signals, under the assumption that the prediction or label distribution of each
example should be similar to its nearest neighbors. Extensive experimental
results on the public SYSU-MM01 and RegDB datasets demonstrate the
effectiveness of the proposed method, surpassing existing state-of-the-art
approach by a large margin of 7.76% mAP on average, which even surpasses some
supervised VI-ReID methods
Optical Coherence Tomography Angiography of Optic Disc Perfusion in Glaucoma
Purpose
To compare optic disc perfusion between normal subjects and subjects with glaucoma using optical coherence tomography (OCT) angiography and to detect optic disc perfusion changes in glaucoma.
Design
Observational, cross-sectional study.
Participants
Twenty-four normal subjects and 11 patients with glaucoma were included.
Methods
One eye of each subject was scanned by a high-speed 1050-nm–wavelength swept-source OCT instrument. The split-spectrum amplitude-decorrelation angiography (SSADA) algorithm was used to compute 3-dimensional optic disc angiography. A disc flow index was computed from 4 registered scans. Confocal scanning laser ophthalmoscopy (cSLO) was used to measure disc rim area, and stereo photography was used to evaluate cup/disc (C/D) ratios. Wide-field OCT scans over the discs were used to measure retinal nerve fiber layer (NFL) thickness.
Main Outcome Measures
Variability was assessed by coefficient of variation (CV). Diagnostic accuracy was assessed by sensitivity and specificity. Comparisons between glaucoma and normal groups were analyzed by Wilcoxon rank-sum test. Correlations among disc flow index, structural assessments, and visual field (VF) parameters were assessed by linear regression.
Results
In normal discs, a dense microvascular network was visible on OCT angiography. This network was visibly attenuated in subjects with glaucoma. The intra-visit repeatability, inter-visit reproducibility, and normal population variability of the optic disc flow index were 1.2%, 4.2%, and 5.0% CV, respectively. The disc flow index was reduced by 25% in the glaucoma group (P = 0.003). Sensitivity and specificity were both 100% using an optimized cutoff. The flow index was highly correlated with VF pattern standard deviation (R[superscript 2] = 0.752, P = 0.001). These correlations were significant even after accounting for age, C/D area ratio, NFL, and rim area.
Conclusions
Optical coherence tomography angiography, generated by the new SSADA, repeatably measures optic disc perfusion and may be useful in the evaluation of glaucoma and glaucoma progression.National Institutes of Health (U.S.) (Grant 1R01 EY023285-01)Rosenbaum's P30EY010572National Institutes of Health (U.S.). Clinical and Translational Science Awards (CTSA) Program (Grant UL1TR000128)Research to Prevent Blindness, Inc. (United States) (Grant R01-EY11289-26)United States. Air Force Office of Scientific Research (FA9550-10-1-0551)German Research Foundation (DFG-HO-1791/11-1)German Research Foundation (DFG-GSC80-SAOT)German Research Foundation (Training Group 1773
Biodegradable Silk Fibroin Nanocarriers to Modulate Hypoxia Tumor Microenvironment Favoring Enhanced Chemotherapy
Biopolymer silk fibroin (SF) is a great candidate for drug carriers characterized by its tunable biodegradability, and excellent biocompatibility properties. Recently, we have constructed SF-based nano-enabled drug delivery carriers, in which doxorubicin (Dox) and atovaquone (Ato) were encapsulated with Arg-Gly-Asp-SF-Polylactic Acid (RSA) to form micellar-like nanoparticles (RSA-Dox-Ato NPs). The RGD peptide was decorated on micellar-like nanoparticles, promoting tumor accumulation of the drug. Meanwhile, Ato, as a mitochondrial complex III inhibitor inhibiting mitochondrial respiration, would reverse the hypoxia microenvironment and enhance chemotherapy in the tumor. In vitro, the biopolymer alone showed extremely low cytotoxicity to 4T1 cell lines, while the RSA-Dox-Ato demonstrated a higher inhibition rate than other groups. Most significantly, the ROS levels in cells were obviously improved after being treated with RSA-Dox-Ato, indicating that the hypoxic microenvironment was alleviated. Eventually, SF-based targeted drug carrier provides biocompatibility to reverse hypoxia microenvironment in vivo for enhancing chemotherapy, strikingly suppressing tumor development, and thereby suggesting a promising candidate for drug delivery system
Inflammation-Related Cytokines of Aqueous Humor in Acute Primary Angle-Closure Eyes
PURPOSE. To measure levels of various inflammation-related cytokines in the aqueous humor of patients with acute primary angle-closure (APAC) and senile cataract. METHODS. Aqueous humor samples were prospectively collected from 23 eyes (12 eyes with current APAC and 11 eyes with previous APAC) of 23 APAC patients and 15 eyes of 15 cataract patients. The levels of 15 inflammation-related cytokines in the aqueous humor of APAC and cataract subjects were measured by using the multiplex bead immunoassay technique. Data on patient demographics and preoperative intraocular pressure (IOP) were also collected for correlation analysis
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