The formation and fate of internal waves in the South China Sea.

Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis, sediment and pollutant transport and acoustic transmission; they also pose hazards for man-made structures in the ocean. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometres from their sources before breaking, making it challenging to observe them and to include them in numerical climate models, which are sensitive to their effects. For over a decade, studies have targeted the South China Sea, where the oceans' most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variability and energy budget, however, owing to the lack of in situ data from the Luzon Strait, where extreme flow conditions make measurements difficult. Here we use new observations and numerical models to (1) show that the waves begin as sinusoidal disturbances rather than arising from sharp hydraulic phenomena, (2) reveal the existence of >200-metre-high breaking internal waves in the region of generation that give rise to turbulence levels >10,000 times that in the open ocean, (3) determine that the Kuroshio western boundary current noticeably refracts the internal wave field emanating from the Luzon Strait, and (4) demonstrate a factor-of-two agreement between modelled and observed energy fluxes, which allows us to produce an observationally supported energy budget of the region. Together, these findings give a cradle-to-grave picture of internal waves on a basin scale, which will support further improvements of their representation in numerical climate predictions.

Impacts of changes in climate, land use, and emissions on global ozone air quality by mid-21st century following selected Shared Socioeconomic Pathways.

Surface ozone (O3) is a major air pollutant and greenhouse gas with significant risks to human health, vegetation, and climate. Uncertainties around the impacts of various critical factors on O3 is crucial to understand. We used the Community Earth System Model to investigate the impacts of land use and land cover change (LULCC), climate, and emissions on global O3 air quality under selected Shared Socioeconomic Pathways (SSPs). Our findings show that increasing forest cover by 20 % under SSP1 in East China, Europe, and the eastern US leads to higher isoprene emissions leading 2-5 ppb increase in summer O3 levels. Climate-induced meteorological changes, like rising temperatures, further enhance BVOC emissions and increase O3 levels by 10-20 ppb in urban areas with high NOx levels. However, higher BVOC emissions can reduce O3 levels by 5-10 ppb in remote environments. Future NOx emissions control reduces O3 levels by 5-20 ppb in the US and Europe in all SSPs, but reductions in NOx and changes in oxidant titration increase O3 in southeast China in SSP5. Increased NOx emissions in southern Africa and India significantly elevate O3 levels up to 15 ppb under different SSPs. Climate change is equally important as emissions changes, sometimes countering the benefits of emissions control. The combined effects of emissions, climate, and land cover result in worse O3 air quality in northern India (+40 %) and East China (+20 %) under SSP3 due to anthropogenic NOx and climate-induced BVOC emissions. Over the northern hemisphere, surface O3 decreases due to reduced NOx emissions, although climate and land use changes can increase O3 levels regionally. By 2050, O3 levels in most Asian regions exceed the World Health Organization safety limit for over 150 days per year. Our study emphasizes the need to consider complex interactions for effective air pollution control and management in the future.

Responses of fine particulate matter (PM2.5) air quality to future climate, land use, and emission changes: Insights from modeling across shared socioeconomic pathways.

Air pollution induced by fine particulate matter with diameter ≤ 2.5 µm (PM2.5) poses a significant challenge for global air quality management. Understanding how factors such as climate change, land use and land cover change (LULCC), and changing emissions interact to impact PM2.5 remains limited. To address this gap, we employed the Community Earth System Model and examined both the individual and combined effects of these factors on global surface PM2.5 in 2010 and projected scenarios for 2050 under different Shared Socioeconomic Pathways (SSPs). Our results reveal biomass-burning and anthropogenic emissions as the primary drivers of surface PM2.5 across all SSPs. Less polluted regions like the US and Europe are expected to experience substantial PM2.5 reduction in all future scenarios, reaching up to ~5 µg m-3 (70 %) in SSP1. However, heavily polluted regions like India and China may experience varied outcomes, with a potential decrease in SSP1 and increase under SSP3. Eastern China witness ~20 % rise in PM2.5 under SSP3, while northern India may experience ~70 % increase under same scenario. Depending on the region, climate change alone is expected to change PM2.5 up to ±5 µg m-3, while the influence of LULCC appears even weaker. The modest changes in PM2.5 attributable to LULCC and climate change are associated with aerosol chemistry and meteorological effects, including biogenic volatile organic compound emissions, SO2 oxidation, and NH4NO3 formation. Despite their comparatively minor role, LULCC and climate change can still significantly shape future air quality in specific regions, potentially counteracting the benefits of emission control initiatives. This study underscores the pivotal role of changes in anthropogenic emissions in shaping future PM2.5 across all SSP scenarios. Thus, addressing all contributing factors, with a primary focus on reducing anthropogenic emissions, is crucial for achieving sustainable reduction in surface PM2.5 levels and meeting sustainable pollution mitigation goals.

Conservative surgical management of simple monostotic fibrous dysplasia of the proximal femur in a 19-year-old basketballer: a case report.

BACKGROUND: Fibrous dysplasia is a rare benign, intramedullary, fibro-osseous lesion. It is thought to be a developmental disorder of bone maturation where normal lamellar bone is replaced by irregular trabecular bone ensnared with fibrous dysplastic tissue that is unable to complete maturation resulting in significant loss of mechanical strength. This, together with the inability to mineralize sufficiently, leads to deformity, pain, and pathological fractures. It typically presents in young adults, with an equal representation in both genders. Surgical intervention is necessary in mild cases with chronic symptoms to prevent pathological fractures or to correct deformities. CASE PRESENTATION: A 19-year-old Chinese woman presented with non-traumatic, nonspecific left hip pain during basketball training. X-rays demonstrated a ground glass lesion, 10 cm in length, in her left femoral neck, which is a classic sign of fibrous dysplasia. No other deformities were noted. She was managed conservatively with analgesia for 6 months; however, her condition did not improve and a decision was made for surgical intervention. The lesion was a type 1 lesion according to the Ippolito radiological classification of fibrous dysplasia, which is a lesion with mild deformities. Therefore, we performed minimal curettage and insertion of a free autologous fibula strut harvested from her left leg, for structural stability. No implants were used. The operation was successful and her postoperative course was uneventful. Histology confirmed the diagnosis of fibrous dysplasia. She achieved partial weight bearing at 4 weeks postoperation, and full weight bearing at 8 weeks, and returned to basketball at 12 weeks. At 1-year follow-up, she returned to competitive basketball and remained pain free with no complications. CONCLUSIONS: Fibrous dysplasia is a rare and benign fibrous tumor of the bone that presents mostly in a young patient population. From our case, we have shown that it is possible to treat young patients with uncomplicated Ippolito type 1 fibrous dysplasia with a minimally invasive approach of using a cortical bone graft for structural augmentation of the affected area, without the use of implants. They are able to fully return to an active and vigorous lifestyle without restriction of activities or long-term risks of orthopedic implant complications.

Risk and economy

In a world of finite resources, balancing risk and economy in the application of fire safety in buildings warrants careful consideration. The NRCC fire risk - cost assessment model, called FiRECAM (Fire Risk Evaluation and Cost Assessment Model), is being developed for that purpose. FiRECAM can assess the expected fire risk to life, property loss and protection cost a particular fire safety desing in a building. The model, therefore, can be used to identify cost effective fire safety designs that can provide the level of safety for occupants as intended by regulations. In this paper, the computer model being developed is described and an example of its application is given. With suitable submodel development, the model can be applied to industrial plants for risk and cost assessment considerations (AU)