Can a Blade-Stopping Mechanism on Circular Table Saws Reduce the Severity of Hand Injuries in Contact Scenarios? A Cadaveric Study.

PURPOSE: Table saws are commonly used woodworking tools that carry a substantial risk of injury. Blade-stopping technology has been developed and has the potential to reduce the frequency and severity of injury. This study aimed to evaluate this technology on human tissue and characterize the resulting injuries. METHODS: Twenty-seven fresh, frozen cadaveric specimen hands were used. Three scenarios were tested, with the specimen (1) moving forward ("forward"); (2) moving backward, such as in a kickback scenario ("reverse"); and (3) dropped from above the saw blade ("top"). Each scenario was tested at both slow (0.001 m/sec) and fast (forward: 0.6 m/sec; reverse: 0.5 m/sec; top: 2.4 m/sec) approach speeds. The severity of the injuries was characterized by anatomic evaluation and confirmed with radiographic evaluation. Injuries were classified as no laceration, superficial soft tissue injury, deep soft tissue injury, and bony injury. RESULTS: For the slow approach speed, the brake cartridge engaged in 100% of the trials for all 3 scenarios, and 100% of the specimens sustained no injuries. Forward testing at a fast approach speed revealed the brake cartridge engaged in 89% of the trials (injuries: 4 superficial, 2 deep, 3 bony). Reverse testing at a fast approach speed revealed the brake cartridge engaged in 11% of trials (injuries: 1 superficial, 8 bony). Top testing at a fast approach speed revealed the brake cartridge engaged in 89% of the trials (injuries: 9 bony). CONCLUSIONS: Modern blade-stopping technology did not prevent all traumatic hand injuries in fast approach speed scenarios, but it reduced the incidence and severity of injuries. The technology was more effective at low approach speed scenarios. CLINICAL RELEVANCE: The findings of this study provide information to help understand the factors that can prevent or reduce the severity of contact injuries (hand, finger, or thumb) for operators of table saws.

Quality control for community-based sea-ice model development.

A new collaborative organization for sea-ice model development, the CICE Consortium, has devised quality control procedures to maintain the integrity of its numerical codes' physical representations, enabling broad participation from the scientific community in the Consortium's open software development environment. Using output from five coupled and uncoupled configurations of the Los Alamos Sea Ice Model, CICE, we formulate quality control methods that exploit common statistical properties of sea-ice thickness, and test for significant changes in model results in a computationally efficient manner. New additions and changes to CICE are graded into four categories, ranging from bit-for-bit amendments to significant, answer-changing upgrades. These modifications are assessed using criteria that account for the high level of autocorrelation in sea-ice time series, along with a quadratic skill metric that searches for hemispheric changes in model answers across an array of different CICE configurations. These metrics also provide objective guidance for assessing new physical representations and code functionality.This article is part of the theme issue 'Modelling of sea-ice phenomena'.

Greenhouse gas mitigation can reduce sea-ice loss and increase polar bear persistence.

On the basis of projected losses of their essential sea-ice habitats, a United States Geological Survey research team concluded in 2007 that two-thirds of the world's polar bears (Ursus maritimus) could disappear by mid-century if business-as-usual greenhouse gas emissions continue. That projection, however, did not consider the possible benefits of greenhouse gas mitigation. A key question is whether temperature increases lead to proportional losses of sea-ice habitat, or whether sea-ice cover crosses a tipping point and irreversibly collapses when temperature reaches a critical threshold. Such a tipping point would mean future greenhouse gas mitigation would confer no conservation benefits to polar bears. Here we show, using a general circulation model, that substantially more sea-ice habitat would be retained if greenhouse gas rise is mitigated. We also show, with Bayesian network model outcomes, that increased habitat retention under greenhouse gas mitigation means that polar bears could persist throughout the century in greater numbers and more areas than in the business-as-usual case. Our general circulation model outcomes did not reveal thresholds leading to irreversible loss of ice; instead, a linear relationship between global mean surface air temperature and sea-ice habitat substantiated the hypothesis that sea-ice thermodynamics can overcome albedo feedbacks proposed to cause sea-ice tipping points. Our outcomes indicate that rapid summer ice losses in models and observations represent increased volatility of a thinning sea-ice cover, rather than tipping-point behaviour. Mitigation-driven Bayesian network outcomes show that previously predicted declines in polar bear distribution and numbers are not unavoidable. Because polar bears are sentinels of the Arctic marine ecosystem and trends in their sea-ice habitats foreshadow future global changes, mitigating greenhouse gas emissions to improve polar bear status would have conservation benefits throughout and beyond the Arctic.

Enhanced simulated early 21st century Arctic sea ice loss due to CMIP6 biomass burning emissions.

The mechanisms underlying decadal variability in Arctic sea ice remain actively debated. Here, we show that variability in boreal biomass burning (BB) emissions strongly influences simulated Arctic sea ice on multidecadal time scales. In particular, we find that a strong acceleration in sea ice decline in the early 21st century in the Community Earth System Model version 2 (CESM2) is related to increased variability in prescribed BB emissions in the sixth phase of the Coupled Model Intercomparison Project (CMIP6) through summertime aerosol-cloud interactions. Furthermore, we find that more than half of the reported improvement in sea ice sensitivity to CO2 emissions and global warming from CMIP5 to CMIP6 can be attributed to the increased BB variability, at least in the CESM. These results highlight a new kind of uncertainty that needs to be considered when incorporating new observational data into model forcing while also raising questions about the role of BB emissions on the observed Arctic sea ice loss.