Browsing by Author "Yang, Wei"
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Item Association of Area Deprivation With Primary Hypertension Diagnosis Among Youth Medicaid Recipients in Delaware(Jama Network Open, 2023-03-15) Baker-Smith, Carissa M.; Yang, Wei; McDuffie, Mary J.; Nescott, Erin P.; Wolf, Bethany J.; Wu, Cathy H.; Zhang, Zugui; Akins, Robert E.Key Points: Question: Is there an association between neighborhood measures of deprivation and hypertension diagnosis in youth? Findings: In this cross-sectional study of 65 452 Delaware Medicaid-insured youths aged 8 to 18 years between 2014 and 2019, residence in neighborhoods with a higher area deprivation index was associated with primary hypertension diagnosis. Meaning: These findings suggest that there is an association between greater neighborhood deprivation and a diagnosis of primary hypertension in youths, which may be an important factor to consider in assessing the presence and prevalence of hypertension in youths. Abstract: Importance: The association between degree of neighborhood deprivation and primary hypertension diagnosis in youth remains understudied. Objective: To assess the association between neighborhood measures of deprivation and primary hypertension diagnosis in youth. Design, Setting, and Participants: This cross-sectional study included 65 452 Delaware Medicaid-insured youths aged 8 to 18 years between January 1, 2014, and December 31, 2019. Residence was geocoded by national area deprivation index (ADI). Exposures: Higher area deprivation. Main Outcomes and Measures; The main outcome was primary hypertension diagnosis based on International Classification of Diseases, Ninth Revision and Tenth Revision codes. Data were analyzed between September 1, 2021, and December 31, 2022. Results: A total of 65 452 youths were included in the analysis, including 64 307 (98.3%) without a hypertension diagnosis (30 491 [47%] female and 33 813 [53%] male; mean [SD] age, 12.5 (3.1) years; 12 500 [19%] Hispanic, 25 473 [40%] non-Hispanic Black, 24 565 [38%] non-Hispanic White, and 1769 [3%] other race or ethnicity; 13 029 [20%] with obesity; and 31 548 [49%] with an ADI ≥50) and 1145 (1.7%) with a diagnosis of primary hypertension (mean [SD] age, 13.3 [2.8] years; 464 [41%] female and 681 [59%] male; 271 [24%] Hispanic, 460 [40%] non-Hispanic Black, 396 [35%] non-Hispanic White, and 18 [2%] of other race or ethnicity; 705 [62%] with obesity; and 614 [54%] with an ADI ≥50). The mean (SD) duration of full Medicaid benefit coverage was 61 (16) months for those with a diagnosis of primary hypertension and 46.0 (24.3) months for those without. By multivariable logistic regression, residence within communities with ADI greater than or equal to 50 was associated with 60% greater odds of a hypertension diagnosis (odds ratio [OR], 1.61; 95% CI 1.04-2.51). Older age (OR per year, 1.16; 95%, CI, 1.14-1.18), an obesity diagnosis (OR, 5.16; 95% CI, 4.54-5.85), and longer duration of full Medicaid benefit coverage (OR, 1.03; 95% CI, 1.03-1.04) were associated with greater odds of primary hypertension diagnosis, whereas female sex was associated with lower odds (OR, 0.68; 95%, 0.61-0.77). Model fit including a Medicaid-by-ADI interaction term was significant for the interaction and revealed slightly greater odds of hypertension diagnosis for youths with ADI less than 50 (OR, 1.03; 95% CI, 1.03-1.04) vs ADI ≥50 (OR, 1.02; 95% CI, 1.02-1.03). Race and ethnicity were not associated with primary hypertension diagnosis. Conclusions and Relevance; In this cross-sectional study, higher childhood neighborhood ADI, obesity, age, sex, and duration of Medicaid benefit coverage were associated with a primary hypertension diagnosis in youth. Screening algorithms and national guidelines may consider the importance of ADI when assessing for the presence and prevalence of primary hypertension in youth.Item Exploiting advantages of non-centric imaging for computer vision(University of Delaware, 2017) Yang, WeiEmploying image features pertaining to scene geometry for reliable scene understanding and reconstruction is an important task in computer vision. The pinhole camera follows the perspective projection principle strictly, i.e project lines to lines and objects in the distance appear smaller than objects close by. Though being identical to the human vision, perspective images seem to lack effective features that can provide cues about the scene structure. In contrast, images captured by non-centric cameras are generally distorted (e.g. project lines to curves). The multi-perspective distortions produce some unique geometric features that will facilitate scene understanding tasks. ☐ In this thesis, I comprehensively exploit the advantages of general non-centric cameras, the XSlit Camera in particular, in scene understanding context. In addition to vanishing point (VP), I first show that another geometric feature exists in non-centric cameras, called the coplanar common point (CCP). A CCP is a point in the image plane corresponding to the intersection of the projections of all lines lying on a common 3D plane. I explore the existence of CCP in general non-centric cameras and show its potential in scene recovery tasks. I show that CCP generally exists in non-centric cameras and derive the necessary and sufficient conditions for CCP to exist. Specifically, I conduct a comprehensive analysis from the perspective of ray-space and caustics and show how to determine the existence of CCP for a general non-centric camera. Experiments show that the CCP analysis provides useful insights on planar structure localization. ☐ Another useful feature exhibited in non-centric images is the depth-dependent aspect ratio (DDAR): aspect ratio (AR) of an object in the image changes according to its depth to the camera. I first conduct a comprehensive analysis to characterize DDAR, infer object depth from its AR, and model recoverable depth range, sensitivity, and error. I show that repeated shape patterns in real Manhattan World scenes can be used for 3D reconstruction using a single XSlit image. I also extend the analysis to model slopes of lines. Specifically, parallel 3D lines exhibit depth-dependent slopes (DDS) in image which can also be used to infer their depths. I validate the analyses using real XSlit cameras, XSlit panoramas, and catadioptric mirrors. Experiments show that DDAR and DDS provide important depth cues and enable effective single-image scene reconstruction. ☐ Finally, I prove that structure-from-motion(SfM) via XSlit camera automatically avoid the scale ambiguity that plagues the perspective camera based solutions. I demonstrate that viewpoint transforms under XSlit camera can also be derived using the fundamental matrix analogous to the perspective case. To address non-linearity and mitigate depth-dependent distortions in XSlit images, I further develop a novel feature matching algorithm based on non-uniform Gaussian kernels. I also extend the bundle adjustment to XSlit images to refine the estimated camera poses. Experiments demonstrate that our XSlit-based SfM approach can reliably estimate camera motion and scene geometry while avoiding ambiguity.Item Rapid changes in the surface carbonate system under complex mixing schemes across the Bering Sea: a comparative study of a forward voyage in July and a return voyage in September 2018(Frontiers in Marine Science, 2023-05-02) Yang, Wei; Wu, Yingxu; Cai, Wei-Jun; Ouyang, Zhangxian; Zhuang, Yanpei; Chen, Liqi; Qi, DiRegulated by the rapid changes in temperature, mixing, and biological production during warm seasons, the surface carbonate system in the Bering Sea is subject to significant spatial-temporal variability. However, the seasonal evolution of the carbon cycle and its controls are less clear due to the lack of observations. Here, we present the carbonate data collected during a forward voyage in July and a return voyage in September 2018 across the Bering Sea. For both voyages, we show distinct dissolved inorganic carbon versus total alkalinity (DIC-TA) relationships and partial pressure of CO2 (pCO2) distribution patterns in the Southern Basin (54-57°N), the Northern Basin (57-59°N), the Slope (59-61°N), the Shelf (61-64°N), and the Bering Strait (>64°N). In the Southern Basin, the Northern Basin, and the Slope, surface water was a two end-member mixing of Rainwater and Bering Summer Water (BSW) during the forward voyage and a two end-member mixing of North Pacific Surface Water (NPSW) and BSW during the return voyage. As a result, the observed DIC was almost consistent with the conservative mixing line, with a slight DIC addition/removal of -8.6~5.8 µmol kg-1, suggesting low biological production/respiration during both voyages. Seasonally, the higher factions of NPSW featuring low pCO2 during the return voyage dominated the pCO2 drawdown from July to September in the Southern Basin and the Slope. On the Shelf, the surface water was a two end-member mixing of plume water from the Anadyr River and BSW during both voyages, but the decreased DIC consumption via biological production from 59.9 ± 25.8 µmol kg-1 to 34.8 ± 14.0 µmol kg-1 contributed to the pCO2 increase from July to September. In the Bering Strait, the coastal area was characterized by the influence of plume water from the Anadyr River in July and the coastal upwelling in September. The high biological production in plume water made a strong CO2 sink during the forward voyage, while the upwelling of carbon-enriched subsurface water with minor DIC consumption made the coastal ecosystem a strong CO2 source during the return voyage. In different geographical regions, the observed seawater pCO2 was much lower than the overlying atmospheric CO2, resulting in a net CO2 sink with fluxes of -2.1~-14.0 mmol m-2 d-1 and -2.5~-11.6 mmol m-2 d-1, respectively, during the forward and return voyages. Highlights 1. The mixing of NPSW featuring low pCO2 dominated the pCO2 drawdown from July to September in the Southern Basin and the Slope. 2. pCO2 in the Bering Strait was dominated by the strong biological production in July and the coastal upwelling in September. 3. High DIC consumption via biological production made the Bering Shelf a strong CO2 sink during both voyages.Item The impact of sea ice melt on the evolution of surface pCO2 in a polar ocean basin(Frontiers in Marine Science, 2024-02-07) Yang, Wei; Zhao, Yu; Wu, Yingxu; Chen, Zijie; Gao, Xiang; Lin, Hongmei; Ouyang, Zhangxian; Cai, Weijun; Chen, Liqi; Qi, DiThe strong CO2 sink in Arctic Ocean plays a significant role in the global carbon budget. As a high-latitude oceanic ecosystem, the features of sea surface pCO2 and air-sea CO2 flux are significantly influenced by sea ice melt; however, our understanding of pCO2 evolution during sea ice melt remains limited. In this study, we investigate the dynamics of pCO2 during the progression of sea ice melt in the western Arctic Ocean based on data from two cruises conducted in 2010 and 2012. Our findings reveal substantial spatiotemporal variability in surface pCO2 on the Chukchi Sea shelf and Canada Basin, with a boundary along the shelf breaks at depths of 250-500 m isobaths. On the Chukchi Sea shelf, strong biological consumption dominates pCO2 variability. Moreover, in Canada Basin, the pCO2 dynamics are modulated by various processes. During the active sea ice melt stage before sea ice concentration decreases to 15%, biological production through photosynthetic processes and dilution of ice melt water lead to a reduction in DIC concentration and subsequent decline in pCO2. Further, these effects are counteracted by the air-sea CO2 exchange at the sea surface which tends to increase seawater DIC and subsequently elevate surface pCO2. Compared to the pCO2 reduction resulting from biological production and dilution effects, the contribution of air-sea CO2 exchange is significantly lower. The combined effects of these factors have a significant impact on reducing pCO2 during this stage. Conversely, during the post sea ice melt stage, an increase in pCO2 resulting from high temperatures and air-sea CO2 exchange outweighs its decrease caused by biological production. Their combined effects result in a prevailing increase in sea surface pCO2. We argue that enhanced air-sea CO2 uptake under high wind speeds also contributes to the high sea surface pCO2 observed in 2012, during both active sea ice melt stage and post sea ice melt stage. The present study reports, for the first time, the carbonate dynamics and pCO2 controlling processes during the active sea ice melt stage. These findings have implications for accurate estimation of air-sea CO2 fluxes and improved modeling simulations within the Arctic Ocean. Highlights ● The decrease in DIC resulting from biological production and dilution of ice melt water tends to reduce pCO2 during the active sea ice melt stage in Canada Basin, although it is counteracted by CO2 uptake at the air-sea interface. ● The increase in pCO2 resulting from high temperatures and air-sea CO2 exchange outweighs its decrease caused by biological production, leading to elevated sea surface pCO2 during the post sea ice melt stage in Canada Basin. ● The enhanced air-sea CO2 uptake under high wind speeds also contributes to the high sea surface pCO2 observed in 2012, during both active sea ice melt stage and post sea ice melt stage.