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Background: Hypertrophic cardiomyopathy (HCM) is commonly associated with mitral valve pathology. A large majority of patients with HCM have elongated anterior and posterior mitral leaflets. There remains debate regarding the necessity and role of concomitant mitral valve surgery at the time of septal myectomy. We aimed to describe the characteristics and share our surgical experiences with this specific group of patients. Methods: This retrospective single‐center study investigates adult patients with HCM, with or without elongated mitral valve leaflets (MVLs), who underwent elective septal myectomy with or without concomitant mitral valve intervention, between January 1, 2016, and June 30, 2020. Clinical data were obtained from institutional medical records as well as the Society of Thoracic Surgeons data registry. The clinical characteristics and in‐hospital surgical outcomes were compared between patients with an elongated MVL and those without. Results: In total, 379 patients underwent septal myectomy, and 22 patients with intrinsic mitral valve disease were excluded. In addition, 23 patients were excluded due to missing data. Of the remaining 334 patients, 131 (39.2%) had elongated MVL and concomitant MVL plication. Patients with elongated MVL had higher rates of preoperative mitral valve systolic anterior motion (SAM) (94.7% vs. 86.7%, p = 0.019) and higher preoperative provoked left ventricular outflow tract gradient (LVOTG) (134.5 mmHg versus 125.3 mmHg, p = 0.046). Post septal myectomy and mitral valve plication, they had lower rates of postoperative residual mitral regurgitation (3.8% vs. 12.8%, p = 0.006), comparable rates of residual SAM (28.2% vs. 31.5%, p = 0.524), postoperative provoked LVOTG (15.4 mmHg vs. 14.0 mmHg, p = 0.317), 30‐day major adverse cardiopulmonary events (2.3% vs. 3.9%, p = 0.409), and mortality (0% vs. 1.0%, p = 0.255). Conclusions: Elongated MVLs contribute more significantly to dynamic LVOT obstruction, as evidenced during provocative testing. Concomitant mitral valve intervention during septal myectomy can be performed safely and may provide an effective strategy to resolve SAM and stress‐induced LVOTG. [ABSTRACT FROM AUTHOR]

Increasing wildfire frequency and severity in high‐elevation seasonal snow zones presents a considerable water resource management challenge across the western United States (U.S.). Wildfires can affect snowpack accumulation and melt patterns, altering the quantity and timing of runoff. While prior research has shown that wildfire generally increases snow melt rates and advances snow disappearance dates, uncertainties remain regarding variations across complex terrain and the energy balance between burned and unburned areas. Utilizing paired in situ data sources within the 2020 Cameron Peak burn area on the Front Range of Colorado, U.S., during the 2021–2022 winter, we found no significant difference in peak snow water equivalent (SWE) magnitude between burned and unburned areas. However, the burned south aspect reached peak SWE 22 days earlier than burned north. During the ablation period, burned south melt rates were 71% faster than unburned south melt rates, whereas burned north melt rates were 94% faster than unburned north aspects. Snow disappeared 7–11 days earlier in burned areas than unburned areas. Net energy differences at the burned and unburned weather station sites were seasonally variable, the burned area snowpack lost more net energy during the winter, but gained more net energy during the spring. Increased incoming shortwave radiation at the burned site was 6x more impactful in altering the net shortwave radiation balance than the decline in surface albedo. These findings emphasize the need for post‐wildfire water resource planning that accounts for aspect‐dependent differences in energy and mass balance to accurately predict snowpack storage and runoff timing. Plain Language Summary: Wildfires are burning more frequently at high‐elevations, where they modify the snowpack. This complicates efforts to predict when snowmelt runoff will occur and the amount of water that will melt from the snowpack. Wildfire generally causes snow to melt earlier in the year and at a faster rate. However, in complex, mountainous terrain, it is not well understood how the magnitude of these changes may differ between neighboring slopes. During the 2021–22 winter in the Cameron Peak burn area (2020) in Colorado, we found that in a high‐elevation snowpack there was no difference in the amount of water accumulated in the snowpack between areas that were burned by the fire and areas that were not. But in areas that burned, the amount of water in the snowpack reached its largest amount 22 days earlier than the areas that did not burn. The snowpack melted faster on both south and north facing slopes in the burned area than comparable unburned areas, causing the burned areas to be snow free 7–11 days earlier. These results highlight the need to account for complex terrain in water resource planning. Key Points: The burned south site reached peak snow water equivalent 22 days earlier than all other sites, which peaked simultaneouslyBurned site melt rates were similar across aspects but exceeded unburned sites by ∼9 mm d−1, causing snow disappearance ∼9 days earlierBurned site net energy balance was dominated by longwave radiation losses in winter and shortwave radiation gains in spring [ABSTRACT FROM AUTHOR]

Snow provides critical water resources for billions of people, making the remote sensing of snow water equivalent (SWE) a highly prioritized endeavor, particularly given ongoing climate change impacts. Synthetic aperture radar (SAR) is a promising method for remote sensing of SWE because radar penetrates snow, and SAR interferometry (InSAR) can be used to estimate changes in SWE (Δ SWE) between SAR acquisitions. We calculated Δ SWE retrievals from 10 NASA L-band (1–2 GHz, ∼25 cm wavelength) uninhabited aerial vehicle SAR (UAVSAR) acquisitions covering a ∼640 km 2 swath in northern Colorado during the winters of 2020 and 2021. UAVSAR acquisitions coincided with ∼117 mm of accumulation in 2020 and ∼282 mm of accumulation in 2021. Δ SWE retrievals were evaluated against measurements of SWE from repeat ground-penetrating radar (GPR) and terrestrial lidar scans (TLSs) collected during the NASA SnowEx time series campaigns at two field sites (total area =∼0.2 km 2) as well as SWE measurements from seven automated stations distributed throughout the UAVSAR swath. For single InSAR pairs, UAVSAR Δ SWE retrievals yielded an overall r of 0.72–0.79 and an RMSE of 19–22 mm when compared with TLS and GPR Δ SWE retrievals. UAVSAR Δ SWE showed some scatter with Δ SWE measured at automated stations for both study years, but cumulative UAVSAR SWE yielded a r of 0.92 and an RMSE of 42 mm when compared to total SWE measured by the stations. Further, UAVSAR Δ SWE RMSEs differed by <10 mm for coherences (i.e., the complex interferometric coherence) of 0.10 to 0.90, suggesting that coherence has only a small influence on the Δ SWE retrieval accuracy. Given the evaluations presented here and in other recent studies, the upcoming NASA-ISRO SAR (NISAR) satellite mission, with a 12 d revisit period, offers an exciting opportunity to apply this methodology globally. [ABSTRACT FROM AUTHOR]

Estimating snow mass in the mountains remains a major challenge for remote-sensing methods. Airborne lidar can retrieve snow depth, and some promising results have recently been obtained from spaceborne platforms, yet density estimates are required to convert snow depth to snow water equivalent (SWE). However, the retrieval of snow bulk density remains unsolved, and limited data are available to evaluate model estimates of density in mountainous terrain. Toward the goal of landscape-scale retrievals of snow density, we estimated bulk density and length-scale variability by combining ground-penetrating radar (GPR) two-way travel-time observations and airborne-lidar snow depths collected during the mid-winter NASA SnowEx 2020 campaign at Grand Mesa, Colorado, USA. Key advancements of our approach include an automated layer-picking method that leverages the GPR reflection coherence and the distributed lidar–GPR-retrieved bulk density with machine learning. The root-mean-square error between the distributed estimates and in situ observations is 11 cm for depth, 27 kgm-3 for density, and 46 mm for SWE. The median relative uncertainty in distributed SWE is 13 %. Interactions between wind, terrain, and vegetation display corroborated controls on bulk density that show model and observation agreement. Knowledge of the spatial patterns and predictors of density is critical for the accurate assessment of SWE and essential snow research applications. The spatially continuous snow density and SWE estimated over approximately 16 km2 may serve as necessary calibration and validation for stepping prospective remote-sensing techniques toward broad-scale SWE retrieval. [ABSTRACT FROM AUTHOR]

Objective: Remission from problem gambling (PG) continues to be a priority of clinicians and researchers. Data from cross-sectional studies indicate that some correlates are more predictive of PG, and existing longitudinal studies have exclusively examined risk factors that predict emergence of PG. This study's objective is to fill in the remaining pieces of the puzzle by identifying factors that might facilitate remission from PG. Method: A stratified sample of 10,199 Canadian adult gamblers were recruited from an online panel. Respondents who screened positively for PG at baseline and completed a follow-up assessment 1 year later (n = 468) were assessed on a series of modifiable gambling, psychosocial, mental health, and substance use variables. A forward stepwise logistic regression was conducted to identify the strongest predictors of remission from PG at follow-up. A Least Absolute Shrinkage and Selection Operator regression was also conducted to confirm the most relevant predictors. Results: Out of 75 candidate variables, 10 were retained by the regression model. Two were related to cessation of specific gambling activities, two were related to gambling motivations, two were psychosocial in nature, two were related to substance use while gambling, and one was related to remission from a mental health disorder. The final and strongest predictor was PG severity at baseline. Conclusions: Although PG remission predictors were mostly gambling-related, psychosocial aspects may also be targeted by stakeholders aiming to reduce PG. Ceasing to use tobacco while gambling and diversifying leisure activities may be promising targets. Other mental health and substance use predictors may still possibly be relevant, but only for a subset of people with PG. Public Health Significance Statement: Gambling-related, psychosocial, and mental health variables predict remission from problem gambling 1 year later. Initial problem gambling severity is the strongest predictor of remission. Cessation of electronic gaming machine gambling and decreasing the frequency of tobacco use while gambling is associated with a higher likelihood of remission. Different predictors of remission may be identified when separating people who gamble into subgroups based on their biopsychosocial profiles. [ABSTRACT FROM AUTHOR]

Ice shelf fractures frequently terminate where they encounter suture zones, regions of material heterogeneity that form between meteoric inflows in ice shelves. This heterogeneity can consist of marine ice, meteoric ice with modified rheological properties, or the presence of fractures. Here, we use radar observations on the Larsen C Ice Shelf, Antarctica, to investigate (i) the termination of a 25 km long rift in the Churchill Peninsula suture zone, which was found to contain ~60 m of accreted marine ice, and (ii) the along-flow evolution of a suture zone originating at Cole Peninsula. We determine a steady state field of basal melting/freezing rates and apply it to a flowline model to delineate the along-flow evolution of layers within the ice shelf. The thickening surface wedge of locally accumulated meteoric ice, which likely has limited lateral variation in its mechanical properties, accounts for ~60% of the total ice thickness near the calving front. Thus, we infer that the lower ~40% of the ice column and the material heterogeneities present there are responsible for resisting fracture propagation and thereby delaying tabular calving events, as demonstrated in the >40 year time series leading up to the 2004/2005 calving event for Larsen C. This likely represents a highly sensitive aspect of ice shelf stability, as changes in the oceanic forcing may lead to the loss of this heterogeneity. ©2014. American Geophysical Union. All Rights Reserved.

A key mechanism for the rapid collapse of both the Larsen A and B Ice Shelves was meltwater-driven crevasse propagation. Basal crevasses, large-scale structural features within ice shelves, may have contributed to this mechanism in three important ways: i) the shelf surface deforms due to modified buoyancy and gravitational forces above the basal crevasse, creating >10 m deep compressional surface depressions where meltwater can collect, ii) bending stresses from the modified shape drive surface crevassing, with crevasses reaching 40 m in width, on the flanks of the basal-crevasse-induced trough and iii) the ice thickness is substantially reduced, thereby minimizing the propagation distance before a full-thickness rift is created. We examine a basal crevasse (4.5 km in length, ∼230 m in height), and the corresponding surface features, in the Cabinet Inlet sector of the Larsen C Ice Shelf using a combination of high-resolution (0.5 m) satellite imagery, kinematic GPS and in situ ground penetrating radar. We discuss how basal crevasses may have contributed to the breakup of the Larsen B Ice Shelf by directly controlling the location of meltwater ponding and highlight the presence of similar features on the Amery and Getz Ice Shelves with high-resolution imagery. © 2012. American Geophysical Union. All Rights Reserved.