An evaluation of the effectiveness of a baby walker safety standard to prevent stair-fall injuries

PROBLEM: During the early 1990s the number of baby walker injuries treated in U.S. hospital emergency departments averaged almost 25,000 annually; about 80% resulted from falls down stairs. After initiating a regulatory proceeding in 1994, the U.S. Consumer Product Safety Commission staff worked with industry to develop requirements to address the stair-fall hazard. This study evaluates the effectiveness of the stair-fall requirements, which became effective in 1997 as part of a revised voluntary standard. METHOD: Annual baby walker emergency department injury rates were constructed for the 1981-2002 study period. A multivariate negative binomial regression model was used to estimate the effectiveness of the stair-fall requirements in reducing the injury rate. RESULTS: The stair-fall requirements reduced the emergency department injury rate by an estimated 63% (95% CI, 52% to 71%). IMPACT ON INDUSTRY: Given the substantial reduction in walker injuries, and the high level of industry conformance with the stair-fall requirements, the Commission terminated its regulatory proceeding in May, 2002. The success of the baby walker project highlights the ability of government and industry to work together cooperatively to develop effective safety improvements for consumer products.     

The influences of climate and hydrology on population dynamics of waterbirds in the lower Murrumbidgee River floodplains in Southeast Australia: Implications for environmental water management

Restoration of waterbird diversity and abundance is a key objective of river system management in Australia. Therefore, understanding the effects of climatic and hydrological variables on waterbird population dynamics is fundamental for successful river restoration programs. We investigated the population dynamics of waterbirds (total abundance) and seven functional waterbird groups in the floodplains of lower Murrumbidgee River. We found a general declining abundance trend from 1983 to 2007, except for the deep water foragers. We modelled the relative contribution of the climatic and hydrological factors to waterbird population decrease using the generalized additive model (GAM) framework after identifying the negative binomial distribution. Most of the seven functional groups were positively related to both annual rainfall and water usage, defined as the total water volume intercepted by the river reach, and the models indicated that rainfall was slightly more important. Temperature also played a role in waterbird abundance: the maximum summer temperature negatively influenced the abundance of dabbling ducks, shoreline foragers and fish eaters, while the minimum winter temperature positively affected the abundance of dabbling ducks and shoreline foragers. Overall, our results support the practice of providing environmental water for sustaining waterbird populations. However, environmental water provision is likely to be most effective when timed to coincide with antecedent rainfall.     

Are helmet laws protecting young motorcyclists?

PROBLEM: The trend in state mandatory motorcycle helmet laws is away from universal coverage to partial coverage statutes that require only young riders to wear a helmet. Among partial coverage states substantial variation exists in this age requirement. How effective are motorcycle helmet laws at reducing young motorcyclist fatalities? METHOD: The dependent variable is the number of motorcyclist fatalities 15-20 years of age. Fixed effects negative binomial regression models are estimated using panel data for all 50 states and Washington DC, for the period 1975-2004. RESULTS: Universal helmet laws are associated with fatality rates that are 31% lower among motorcyclists 15-20 years of age. In contrast, partial coverage laws targeting young motorcyclists are statistically unrelated to a reduction in the fatality rates of this age group. DISCUSSION: The long-term consequence of the move away from universal helmet laws will be an increased level of risk faced by young motorcyclists. In many states, mandatory motorcycle helmet laws are not protecting even young riders.     

Achievements,challenges and global implications of China’s carbon neutral pledge

China has been committed to achieving carbon neutrality by 2060. China’s pledge of carbon neutrality will play an essential role in galvanising global climate action, which has been largely deferred by the Covid-19 pandemic. China’s carbon neutrality could reduce global warming by approximately 0.2–0.3 °C and save around 1.8 million people from premature death due to air pollution. Along with domestic benefits, China’s pledge of carbon neutrality is a “game-changer” for global climate action and can inspire other large carbon emitters to contribute actively to mitigate carbon emissions, particularly countries along the Belt and Road Initiative (BRI) routes. In order to achieve carbon neutrality by 2060, it is necessary to decarbonise all sectors in China, including energy, industry, transportation, construction, and agriculture. However, this transition will be very challenging, because major technological breakthroughs and large-scale investments are required. Strong policies and implementation plans are essential, including sustainable demand, decarbonizing electricity, electrification, fuel switching, and negative emissions. In particular, if China can peak carbon emissions earlier, it can lower the costs of the carbon neutral transition and make it easier to do so over a longer time horizon. China’s pledge of carbon neutrality by 2060 and recent pledges at the 26^th UN Climate Change Conference of the Parties (COP26) are significant contributions and critical steps for global climate action. However, countries worldwide need to achieve carbon neutrality to keep the global temperature from growing beyond the level that will cause catastrophic damages globally.     

杭州城区空气负离子特征及其与气象因子的关系

以杭州市典型的居民区为研究区域,对空气负离子浓度和其他气象因子进行了连续12个月的定点监测,分析了研究区空气负离子的日变化动态特征,以及空气负离子与气象因子的相关关系。结果表明,研究区的空气负离子浓度平3 3 3均值为241.49个/cm,空气负离子浓度日变化最大值出现在凌晨4:00 307.92个/cm,最小值出现在21:00,为193.06个/cm;空气负离子浓度与温度、水汽压和风速均成正相关,与紫外线强度、湿度和二氧化碳浓度成负相关。     

Molecular characterization of root exudates using Fourier transform ion cyclotron resonance mass spectrometry

The release of root exudates (REs) provides an important source of soil organic carbon. This work revealed the molecular composition of REs of different plant species including alfalfa (Medicago sativa L.), bean (Phaseolus vulgaris L.), barley (Hordeum vulgare L.), maize (Zea mays), wheat (Triticum aestivum L.), ryegrass (Lolium perenne L.) and pumpkin (Cucurbita maxima) using electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The combination of positive ion mode (+ESI) and negative ion mode (-ESI) increased the number of the molecules detected by ESI FT-ICR MS, and a total of 8758 molecules were identified across all the samples. In detail, lipids and proteins and unsaturated hydrocarbons were more easily detected in +ESI mode, while aromatic compounds with high O/C were readily ionized in -ESI mode, and only 38% of the total assigned formulas were shared by -ESI and +ESI modes. Multivariate statistical analysis of the formulas indicated that the close related plants species secreted REs with similar molecular components. Moreover, the unsaturation degree and nitrogen content were the two key parameters able to distinguish the similarities and differences of molecular components of REs between plant species. The results provided a feasible analysis method for characterization of the molecular components of REs and for the first time characterized the molecular components of REs of a variety of plant species using ESI FT-ICR MS.     

武钢某楼大梁开裂原因及修复加固

通过对大梁开裂原因的分析,指出在设计和施工中应注意的事项,并为加固处理提供依据。     

总大肠菌群测定中如何避免出现不定值

现行的环境监测分析方法与有关技术规范中总大肠菌群检数表里所列的几个不定值(“<”或“>”)给区域环境综合分析与评价工作带来一定的困难.为了避免在实测数据中出现不定值,实验分析人员应充分了解待检水样的环境因素以便确定合适的分析方法.对污染较重的水样要适当提高稀释倍数直至出现阴性反应.能否选择出正确的稀释度是实验成败的关键.     

Probabilistic multiple model neural network based leak detection system: Experimental study

This paper presents an effective decision making system for leak detection based on multiple generalized linear models and clustering techniques. The training data for the proposed decision system is obtained by setting up an experimental pipeline fully operational distribution system. The system is also equipped with data logging for three variables; namely, inlet pressure, outlet pressure, and outlet flow. The experimental setup is designed such that multi-operational conditions of the distribution system, including multi pressure and multi flow can be obtained. We then statistically tested and showed that pressure and flow variables can be used as signature of leak under the designed multi-operational conditions. It is then shown that the detection of leakages based on the training and testing of the proposed multi model decision system with pre data clustering, under multi operational conditions produces better recognition rates in comparison to the training based on the single model approach. This decision system is then equipped with the estimation of confidence limits and a method is proposed for using these confidence limits for obtaining more robust leakage recognition results.     

安全管理系统的负熵机理及其模型化控制的探讨

试用现代系统论的重要学说——耗散结构论的观点,研究安全管理工程的各种属性,指出其具有普遍意义的负熵机理。在对安全状态函数分析的基础上,建立起安全管理工程的数学模型并进行了探讨。论述了模型化控制方法是深入发展科学型,定量型,预测型安全管理科学的重要途径。