Barotolerance of Staphylococcus aureus is increased by incubation at below 0 degrees C prior to hydrostatic pressure treatment

The effect of preincubation under low temperatures on inactivation of Staphylococcus aureus IFO 13276 by hydrostatic pressure treatment (HPT) was investigated. Preincubation before HPT was carried out by submerging cell suspension in an ethylene glycol bath at temperatures from 30 to −20 °C for 15 min. After HPT at the same temperatures, survivors of incubated S. aureus was not significantly (P>0.05) influenced when preincubation took place at temperatures above 0 °C. Survivors of incubated S. aureus, however, were approximately two log cycles higher when preincubation took place at temperatures below 0 °C. This increase in barotolerance of S. aureus was not observed in the presence of 40 μg/ml of chloramphenicol.     

水适应性景观认知与研究框架解析——以北京市门头沟地区为例

Water adaptive landscape is a typical regional complex formed by mutual adaptation between humans and water systems. As a subfield of adaptation research in the context of global changes, research on water adaptive landscapes emphasizes the combination of research perspectives and methods on water, adaptation, and landscape. This paper first reviews the concepts of “adaptation” in related disciplines, summarizes the primary attributes of adaptation, and puts forward a definition and research scope of water adaptive landscape. While pointing out that research on water adaptive landscapes mainly studies the processes, capacities, and strategies of relevant spatial forms and behavioral patterns, it also presents the research progress and achievements in the experience of spatial patterns and construction, evaluation, and narrative analysis, before proposing a research framework of water adaptive landscape by focusing on Mentougou District of Beijing. Finally, it offers prospects for future study from the aspects of research framework, quantitative methods, social cognition, and feasibility.     

Thermal comfort for naturally ventilated residential buildings in Harbin

This field study was conducted during summer 2009 in Harbin, northeast of China in order to investigate human responses to the thermal conditions in naturally ventilated residential buildings in cold climate. We visited 257 families in six residential communities and collected 423 sets of physical data and subjective questionnaires. The neutral temperature is 23.7 °C, with the clothing insulation of 0.54 clo. The neutral temperature in Harbin is lower than neutral temperatures in warm climates by others, which is in accordance with the thermal adaptive model. 80% of the occupants can accept the air temperature range of 21.5-31.0 °C, which is wider than the summer comfort temperature limits by the adaptive model. The preferred temperature range fell between 24.0 °C and 28.0 °C. About 57.9% of the subjects voted “no change” with the humid range of 40% and 70%. 61.5% of the occupants voted “no change” with the air velocity within the range of 0.05-0.30 m/s. In summer, occupants preferred air velocity of lower than 0.25 m/s even at higher indoor temperature, which is different from the other field studies. The Harbin occupants in naturally ventilated dwellings can achieve thermal comfort by operable windows instead of running air-conditioners.     

Numerical simulation of natural ventilation of a factory roof cavity

The study targets the reduction of roof solar heat gain through the use of natural ventilation in a cavity of a factory roof. In the laboratory experiment [1], the average air velocity reached 0.25 m/s. A simulation program was developed to calculate the heat and air flow attained in the experiment. An airflow passage was divided into sections to trace the pattern of the air temperature rise. When the cavity was divided into 20 sections, it was enough to trace the temperature rise pattern, and hence to calculate buoyancy for natural ventilation. Then the simulated air velocities, temperatures and heat transportations were compared with the experimental results. The molecular viscosity and thermal conductivity of the air were modified to adjust the simulation results to the experimental results in a wide range of experimental conditions. When they were multiplied with a magnitude of 30 equally, the least root mean square of the ratio of deviations of the heat transportation was obtained. This simulation could predict the heat transportation as a result of natural ventilation with a root mean square of the deviation of 0.25 in a short calculation time.     

Evidence needed to manage freshwater ecosystems in a changing climate: Turning adaptation principles into practice

It is widely accepted that climate change poses severe threats to freshwater ecosystems. Here we examine the scientific basis for adaptively managing vulnerable habitats and species. Our views are shaped by a literature survey of adaptation in practice, and by expert opinion. We assert that adaptation planning is constrained by uncertainty about evolving climatic and non-climatic pressures, by difficulties in predicting species- and ecosystem-level responses to these forces, and by the plasticity of management goals. This implies that adaptation measures will have greatest acceptance when they deliver multiple benefits, including, but not limited to, the amelioration of climate impacts. We suggest that many principles for biodiversity management under climate change are intuitively correct but hard to apply in practice. This view is tested using two commonly assumed doctrines: “increase shading of vulnerable reaches through tree planting” (to reduce water temperatures); and “set hands off flows” (to halt potentially harmful abstractions during low flow episodes). We show that the value of riparian trees for shading, water cooling and other functions is partially understood, but extension of this knowledge to water temperature management is so far lacking. Likewise, there is a long history of environmental flow assessment for allocating water to competing uses, but more research is needed into the effectiveness of ecological objectives based on target flows. We therefore advocate more multi-disciplinary field and model experimentation to test the cost-effectiveness and efficacy of adaptation measures applied at different scales. In particular, there is a need for a major collaborative programme to: examine natural adaptation to climatic variation in freshwater species; identify where existing environmental practice may be insufficient; review the fitness of monitoring networks to detect change; translate existing knowledge into guidance; and implement best practice within existing regulatory frameworks.     

实例推理和规则推理在实例修改中的应用

在CBR系统中实例修改是一个关键环节,该文通过分析几种实例修改的方法,提出了将实例推理和规则推理进行整合后引入到实例修改过程中,建立修改规则库来完成实例修改,并就如何建立修改规则库进行了说明,为建立智能化的实例修改提供一种思路。     

基于多尺度自注意卷积的足迹压力图像检索算法

为了提高足迹压力图像检索的精度,提出基于多尺度自注意卷积的足迹压力图像检索算法.首先,对足迹压力图像进行角度校正、对齐、擦除等预处理操作,减小图像角度等因素对特征提取的影响.再由多个并行分支的空洞卷积和自适应注意模块构成的多尺度自注意卷积模块自适应地提取可判别特征.最后,由全局特征分支、残缺性评分掩模分支构成残缺性评分模块,得到共同残缺性评分矩阵,利用该评分矩阵对可判别特征进行加权组合,提高网络对残缺足迹共同可见区域的关注程度.实验表明,在构建的FootPrintImage数据集上,文中算法具有较高的首中准确率和平均检索精度.     

联合类间及域间分布适配的迁移学习方法

在域间分布适配的过程中,容易丢失一些重要的域自身信息,在源域上难以训练获得一个有效的分类器,影响其在目标域上的泛化与标注性能.基于此种情况,文中提出联合类间及域间分布适配的迁移学习方法.通过学习一个公共投影矩阵,分别将源域与目标域映射到一个公共子空间上.采用最大均值差异方法分别度量类间及域间分布距离.在目标函数的优化过程中,不但显式地使域间分布差异变小,而且增大不同类别间的差异性,提高源域与目标域之间知识迁移的性能.在迁移学习数据集上的实验表明文中方法的有效性.     

AAL2分组话音系统信元装配时延的研究

该文研究将AAL2分组填入ATM信元载荷域时的信元装配时延。得出结论:ATM信元装配时延由话音源编码速率、分组占用时长以及接入AAL2分组话音复接器中的话音源个数确定。当话音源编码速率较低,接入AAL2分组话音复接器中的话音源数较小时,信元装配时延可能很大,需要设置定时器以限制信元装配时延,例如当话音源编码速率为8kb/s时,可令定时器的取值为3ms;当话音源编码速率为32kb/s时,若分组占用时长为5ms,一般无需使用定时器。     

基于联合分布适配的水下声源测距算法研究

水下声源被动测距基于接收数据中声源辐射的声压信号,通过特定方法在空域中搜索声源位置参数,是一个参数估计问题。对于参数估计问题,机器学习方法通常将其转化为分类问题,相比于传统匹配场处理(MFP)具有更准确的估计能力,并且无需先验的声场环境信息。但当训练数据和测试数据的概率密度函数服从不同的分布或者训练数据严重不足时,传统机器学习方法下的分类器预测效果通常较差。因此,该文提出基于联合分布适配(JDA)的水下声源测距算法,该算法使用JDA寻找恰当的变换矩阵进行数据映射,从而减小不同数据域间分布差异,实现源域到目标域的迁移。对经过JDA后数据进行实验的结果表明,JDA可以有效降低在不同时间和不同方位的水声场中获取航迹数据之间的差异,使得基于源域训练的分类器对目标域预测结果的均方根误差(RMSE)和平均绝对误差(MAE)降低了超过30%,从而实现对声源更准确的距离估计。