Strong constraints on aerosol-cloud interactions from volcanic eruptions.

Aerosols have a potentially large effect on climate, particularly through their interactions with clouds, but the magnitude of this effect is highly uncertain. Large volcanic eruptions produce sulfur dioxide, which in turn produces aerosols; these eruptions thus represent a natural experiment through which to quantify aerosol-cloud interactions. Here we show that the massive 2014-2015 fissure eruption in Holuhraun, Iceland, reduced the size of liquid cloud droplets-consistent with expectations-but had no discernible effect on other cloud properties. The reduction in droplet size led to cloud brightening and global-mean radiative forcing of around -0.2 watts per square metre for September to October 2014. Changes in cloud amount or cloud liquid water path, however, were undetectable, indicating that these indirect effects, and cloud systems in general, are well buffered against aerosol changes. This result will reduce uncertainties in future climate projections, because we are now able to reject results from climate models with an excessive liquid-water-path response.

Erratum: Strong constraints on aerosol-cloud interactions from volcanic eruptions.

This corrects the article DOI: 10.1038/nature22974.

Predictability of European 2016/2017.

Winter 2016/2017 was one of the driest on record for central Europe and the United Kingdom. This was the result of blocked atmospheric circulation with high pressure centred over North-West Europe dominating the winter mean circulation pattern. Using large ensembles of simulated winters, we find that the observed winter 2016/2017 circulation was very similar in pattern and strength to the circulation associated with the top 10% of driest Central European winters. Here, we explore whether seasonal forecasts were able to predict this circulation pattern. Despite the fact that the observed circulation anomaly did not project on to the North Atlantic Oscillation (NAO), we find that forecasts starting in November did predict a high-pressure anomaly over North-Western Europe. We use two independent data sets, and methods, to probe the drivers of this circulation pattern. We find evidence for a Rossby Wave propagating out of the tropical Atlantic where there were anomalous local rainfall anomalies. This case study is another example of real-time seasonal forecast skill for Europe and provides evidence for predictability beyond the NAO pattern.

Global impacts of the 1980s regime shift.

Despite evidence from a number of Earth systems that abrupt temporal changes known as regime shifts are important, their nature, scale and mechanisms remain poorly documented and understood. Applying principal component analysis, change-point analysis and a sequential t-test analysis of regime shifts to 72 time series, we confirm that the 1980s regime shift represented a major change in the Earth's biophysical systems from the upper atmosphere to the depths of the ocean and from the Arctic to the Antarctic, and occurred at slightly different times around the world. Using historical climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and statistical modelling of historical temperatures, we then demonstrate that this event was triggered by rapid global warming from anthropogenic plus natural forcing, the latter associated with the recovery from the El Chichón volcanic eruption. The shift in temperature that occurred at this time is hypothesized as the main forcing for a cascade of abrupt environmental changes. Within the context of the last century or more, the 1980s event was unique in terms of its global scope and scale; our observed consequences imply that if unavoidable natural events such as major volcanic eruptions interact with anthropogenic warming unforeseen multiplier effects may occur.

Forecast cooling of the Atlantic subpolar gyre and associated impacts.

Decadal variability in the North Atlantic and its subpolar gyre (SPG) has been shown to be predictable in climate models initialized with the concurrent ocean state. Numerous impacts over ocean and land have also been identified. Here we use three versions of the Met Office Decadal Prediction System to provide a multimodel ensemble forecast of the SPG and related impacts. The recent cooling trend in the SPG is predicted to continue in the next 5 years due to a decrease in the SPG heat convergence related to a slowdown of the Atlantic Meridional Overturning Circulation. We present evidence that the ensemble forecast is able to skilfully predict these quantities over recent decades. We also investigate the ability of the forecast to predict impacts on surface temperature, pressure, precipitation, and Atlantic tropical storms and compare the forecast to recent boreal summer climate.

Understanding unassisted falls: effects of nurse staffing level and nursing staff characteristics.

Hierarchical Poisson modeling was used to explore hospital and nursing unit characteristics as predictors of the unassisted fall rate. Longitudinal data were collected from 1502 units in 248 US hospitals. The relation between the fall rate and total nurse staffing was positive at lower staffing levels and negative for levels around and above the median. The fall rate was negatively associated with registered nurse skill mix and average registered nurse tenure on the unit.

A successful prediction of the record CO2 rise associated with the 2015/2016 El Niño.

In early 2016, we predicted that the annual rise in carbon dioxide concentration at Mauna Loa would be the largest on record. Our forecast used a statistical relationship between observed and forecast sea surface temperatures in the Niño 3.4 region and the annual CO2 rise. Here, we provide a formal verification of that forecast. The observed rise of 3.4 ppm relative to 2015 was within the forecast range of 3.15 ± 0.53 ppm, so the prediction was successful. A global terrestrial biosphere model supports the expectation that the El Niño weakened the tropical land carbon sink. We estimate that the El Niño contributed approximately 25% to the record rise in CO2, with 75% due to anthropogenic emissions. The 2015/2016 CO2 rise was greater than that following the previous large El Niño in 1997/1998, because anthropogenic emissions had increased. We had also correctly predicted that 2016 would be the first year with monthly mean CO2 above 400 ppm all year round. We now estimate that atmospheric CO2 at Mauna Loa would have remained above 400 ppm all year round in 2016 even if the El Niño had not occurred, contrary to our previous expectations based on a simple extrapolation of previous trends.This article is part of a discussion meeting issue 'The impact of the 2015/2016 El Niño on the terrestrial tropical carbon cycle: patterns, mechanisms and implications'.

Tobacco and alcohol use among firefighters during their first 3 years of service.

Firefighters constitute an understudied occupational group that are exposed to a great deal of occupational stress including potentially traumatic stress. As such, higher prevalence rates of posttraumatic stress disorder (PTSD) and substance use disorders have been observed within this population; however, very little is known about the trajectories of health-risk behaviors among firefighters in response to occupational stress over time. The present study enrolled 322 fire service recruits from 7 urban U.S. professional fire departments and followed them through the first 3 years of service. All enrollees were free of Axis I psychopathology at the time of baseline assessments, which were conducted while participants were still enrolled in the fire academy. We hypothesized that: (a) firefighters who used tobacco would have higher levels of alcohol use over time; and (b) firefighters with higher levels of traumatic exposure and mental health symptoms would evidence a stronger multisubstance risk pattern. Analyses provided support for our first hypothesis and revealed that depressive symptoms (but neither trauma exposure nor PTSD symptoms) moderated the alcohol-tobacco relationship. The clinical and public safety implications of these results are discussed. (PsycINFO Database Record

An unexpected disruption of the atmospheric quasi-biennial oscillation.

One of the most repeatable phenomena seen in the atmosphere, the quasi-biennial oscillation (QBO) between prevailing eastward and westward wind jets in the equatorial stratosphere (approximately 16 to 50 kilometers altitude), was unexpectedly disrupted in February 2016. An unprecedented westward jet formed within the eastward phase in the lower stratosphere and cannot be accounted for by the standard QBO paradigm based on vertical momentum transport. Instead, the primary cause was waves transporting momentum from the Northern Hemisphere. Seasonal forecasts did not predict the disruption, but analogous QBO disruptions are seen very occasionally in some climate simulations. A return to more typical QBO behavior within the next year is forecast, although the possibility of more frequent occurrences of similar disruptions is projected for a warming climate.

Aspergillus mastoiditis in a patient with systemic lupus erythematosus: a case report.

Fungal mastoiditis caused by Aspergillus fumigatus predominantly occurs in immunocompromised patients. Invasive temporal bone mycoses are rare. They are usually associated with host immunodeficiency, are difficult to diagnose, and many cases are fatal. Treatment consists of antifungal chemotherapy, surgical debridement, and attempts to control the underlying immunological condition. Published reports describe patients with previous ear pathology and associated facial nerve dysfunction. We report a case in a patient with systemic lupus erythematosus. A good outcome followed surgical debridement and the use of a new triazole antifungal agent, voriconazole. Our patient's facial nerve function was unaffected. The presence of normal facial nerve function, however, does not exclude the possibility of invasive fungal mastoiditis.

Regional climate impacts of a possible future grand solar minimum.

Any reduction in global mean near-surface temperature due to a future decline in solar activity is likely to be a small fraction of projected anthropogenic warming. However, variability in ultraviolet solar irradiance is linked to modulation of the Arctic and North Atlantic Oscillations, suggesting the potential for larger regional surface climate effects. Here, we explore possible impacts through two experiments designed to bracket uncertainty in ultraviolet irradiance in a scenario in which future solar activity decreases to Maunder Minimum-like conditions by 2050. Both experiments show regional structure in the wintertime response, resembling the North Atlantic Oscillation, with enhanced relative cooling over northern Eurasia and the eastern United States. For a high-end decline in solar ultraviolet irradiance, the impact on winter northern European surface temperatures over the late twenty-first century could be a significant fraction of the difference in climate change between plausible AR5 scenarios of greenhouse gas concentrations.

Central placement of the screw in simulated fractures of the scaphoid waist: a biomechanical study.

BACKGROUND: Recent reports on internal fixation of acute fractures of the scaphoid waist have demonstrated higher rates of central placement of the screw when cannulated screws were used than when noncannulated screws were used. This cadaveric study was designed to determine whether central placement in the proximal fragment of the scaphoid offers a biomechanical advantage. METHODS: Eleven matched pairs of scaphoids were removed from fresh cadaveric wrists. Each scaphoid was placed in a custom manufactured jig that was used to create reproducible central and eccentric positioning of the guidewire. Then a linear osteotomy was made followed by placement of a Herbert-Whipple cannulated screw to fix the osteotomy. The specimen was then potted in a holder with use of polymethylmethacrylate with a Kirschner wire passed through the proximal end of the scaphoid and placed into a fixture with a pneumatically driven plunger resting on the surface of the distal pole. The load acting through the plunger was measured with use of a load-cell, and its excursion was measured with use of a linear variable differential transformer. Stiffness, load at 2 mm of displacement, load at failure, and mechanism of failure were measured, and the two groups were compared with regard to stiffness and strength. RESULTS: Central placement of the screw in the proximal fragment of the scaphoid had superior results compared with those after eccentric positioning of the screw. Fixation with central placement of the screw demonstrated 43% greater stiffness (12.7 N per mm compared with 8.9 N per mm; p < 0.01), 113% greater load at 2 mm of displacement (126 N compared with 59.1 N; p < 0.01), and 39% greater load at failure (712 N compared with 513 N; p > 0.05). CONCLUSIONS AND CLINICAL RELEVANCE: Central placement of the screw in the proximal fragment of the scaphoid offers a biomechanical advantage in the internal fixation of an osteotomy of the scaphoid waist. Clinical efforts and techniques that facilitate central placement of the screw in the fixation of fractures of the scaphoid waist should be encouraged.

Comparison of bipolar scissors and bipolar forceps in tonsillectomy.

Bipolar diathermy scissors tonsillectomy is a relatively new surgical technique. We conducted a prospective study of 90 patients to compare this technique with bipolar forceps tonsillectomy. We found that the use of the bipolar scissors required significantly less operating time (mean: 3.03 min less) and allowed patients to resume eating solid food more rapidly (mean: 40.35 min earlier). Bipolar scissors tonsillectomy was safe, and there were no intraoperative complications or primary hemorrhages. A postoperative follow-up telephone survey revealed that patients who underwent scissors tonsillectomy experienced no more morbidity than did the forceps group during the first 2 weeks after surgery. We conclude that bipolar scissors tonsillectomy is a safe and rapid technique that can be used successfully as an outpatient procedure.

A cadaver model to evaluate the accuracy and reproducibility of plain radiograph step and gap measurements for intra-articular fracture of the distal radius.

PURPOSE: The purpose of this study was to determine the accuracy and reproducibility of intra-articular step-off and gap displacements measured on plain radiographs using a standard cadaver model. METHODS: Twenty-two physicians, in a blinded randomized fashion using a standard technique, examined the radiographs of 12 unique combinations of step and gap displacement created by a 3-part intra-articular osteotomy of the distal radius. Observer accuracy, inter- and intraobserver agreement, and tolerance limits were calculated. RESULTS: The results of this study suggest that observers, independent of skill level, may measure step-off and gap displacements accurately to within .62 +/- .53 mm (95% confidence interval = .59-65). The accuracy of measurement was influenced by the quality of the radiograph. Intraclass correlation coefficient scores showed "substantial" (.78) to "almost perfect" (.81) inter- and intraobserver agreement. CONCLUSIONS: These data can aid in the interpretation of clinical studies of acute distal radius fractures that are based on plain radiography.