What affects children’s outcomes: house characteristics or homeownership?

We study the impact of housing conditions on the educational outcomes of young persons in Switzerland. We focus on children aged 15–19, who are potentially enrolled in or graduates of high school or vocational training programs, and young adults aged 20–24, who are potentially students in or graduates of university or other tertiary institutions. Housing conditions are characterized in three ways: whether the parents rent or own the dwelling, the type of dwelling (house or apartment), and a measure of crowding (occupants per room). We find that the density of residents in the dwelling is the only influential housing characteristic. Crowding directly affects the outcomes of children aged 15–19 and presumably indirectly affects the outcomes of young adults given that admission to university study requires completion of high school. None of the other housing characteristics affects children’s outcomes. In particular, homeownership is not statistically significant in any of our estimations.     

Effect of Crowding in Metro Carriages on Travelers’ Disutility: An Evidence from Guangzhou Metro

地铁车厢内拥挤度影响研究——以广州地铁为例

刘建荣

（华南理工大学 土木与交通学院,广州 510641）

创新点说明：

论文放弃了车厢内拥挤度效用与车厢内拥挤度是线性关系的假设,对不同拥挤度下的时间价值进行了研究,同时分析了通勤者、非通勤者、大学生在不同拥挤度下的时间价值。

研究目的：

地铁车厢内拥挤度、出行者类别对出行行为选择具有重要影响,为此本文分析地铁车厢内拥挤度、出行者类别对出行者出行选择行为的影响。

研究方法：

研究采用离散选择模型,数据利用陈述性偏好调查得到。

研究结果：

基于陈述性偏好调查得到的数据,利用离散选择模型进行分析发现,地铁车厢内站立乘客的密度与时间价值呈现非线性关系。当出行者从有座到无座时,时间价值增加块多;当站立乘客密度从1人/m²到4人/m²时,时间价值变化不大;当站立乘客密度超过到4人/m²时,时间价值随着站立乘客密度增加而显著增加。此外,通勤者、非通勤者、大学生在同一拥挤度情况下,时间价值有较大差异。

结论：

在分析出行者出行选择行为时,应考虑地铁车厢内拥挤度以及出行者类别对出行选择行为的影响。

关键词：拥挤度;站立乘客密度;陈述性偏好;负效用;地铁

     

基于两阶段搜索算法的多峰函数优化

多峰优化问题需要搜索多个最优值（全局最优／局部最优）,这给传统的优化算法带来很大程度上的挑战。本文提出了一种两阶段算法求解多峰优化问题。第一阶段采用带有邻域变异策略的排挤差分演化算法进行粗粒度搜索,在适应度景观上尽可能多的找到最优解的大概位置。搜索一定代数之后,调用DMC聚类方法把搜索种群划分成多个聚类,然后在每个聚类上调用协方差矩阵自适应演化策略算法进行精细搜索。另外,本文还提出搜索点补充策略用于平衡每个聚类的大小及增加算法初期的搜索能力。我们提出的方法和9个较新的经典算法在两个基准测试集上进行了大量对比测试,结果表明新算法是有效的,在大多数测试函数上都优于其它算法。     

多糖的共价键合对7S球蛋白凝胶性能的影响

引入细胞学说中的大分子拥挤体系并在该体系通过Maillard反应制备了大豆7S球蛋白(b-conglycinin,7S)和葡聚糖(dextran,Dex)的共价复合物,利用转谷氨酰胺酶(transglutaminase,TGase)的交联作用制得蛋白-多糖共价复合物凝胶.对其流变学、质构特性及微结构进行分析.结果表明,在大分子拥挤环境下,7S-葡聚糖比例为2:1的共价复合物制得具有致密且孔洞分布均匀的凝胶网络结构.单纯的蛋白自聚集或者与多糖的共混状态时形成的凝胶弹性模量都较高,但蛋白过度的聚集并不能得到孔洞均匀的凝胶网络结构,共价复合物制备的凝胶中葡聚糖的共价键合作用抑制了TGase交联过程中蛋白质分子间发生过度的相互作用.形貌学观察表明,共价复合物制备的凝胶形成了网络孔径均匀且非常致密的凝胶网络结构.     

基于BQPSO的电网多目标优化规划

对于多目标电网优化规划问题,建立以经济性和可靠性为目标的电网规划模型,通过二进制编码的量子粒子群算法进行优化。为了提高最优解的多样性和分布性,采用拥挤距离排序的方法对外部存储器中的最优解进行更新和维护,使得算法找到尽可能多的Pareto最优解。仿真结果显示,基于拥挤距离排序的二进制量子粒子群算法比其他智能算法寻得的最优解有更好的分布性和收敛性。     

Tin Whisker Growth Induced by High Electron Current Density

The effect of electric current on the tin whisker growth on Sn stripes was studied. The Sn stripes, 1 μm in thickness, were patterned on silicon wafers. The design of the Sn stripes allowed the simultaneous study of the effect of current crowding and current density. Current stressing was performed in ovens set at 30, 50, or 70°C, and the current density used ranged from 4.5 × 10⁴ A/cm² to 3.6 × 10⁵ A/cm². It was found that the stress induced by the electric current caused the formation of many Sn whiskers. A higher current density caused more Sn whiskers to form. Of the three temperatures studied, 50°C was the most favorable one for the formation of the Sn whiskers. In addition, the current-crowding effect also influenced whisker growth.     

Diverse Effects of Macromolecular Crowding on the Sequential Glycan‐Processing Pathway Involved in Glycoprotein Quality Control

Compared with in vitro conditions, the intracellular environment is highly crowded with biomolecules; this has numerous effects on protein functions, including enzymatic activity. We examined the effects of macromolecular crowding on glycan processing of N‐glycoprotein in the endoplasmic reticulum as a model sequential metabolic pathway. Experiments with synthetic substrates of physiological glycan structure clearly showed that the first half of the pathway (glucose trimming) was accelerated, whereas the second (mannose trimming) was decelerated under molecular crowding conditions. Furthermore, calreticulin, a lectin‐like molecular chaperone, bound more strongly to a glycan‐processing intermediate under these conditions. This study demonstrates the diverse effects of molecular crowding on sequential enzymatic processing, and the importance of the effects of macromolecular crowding on in vitro assays for understanding sequential metabolic pathways.     

膜系统下的一种多目标优化算法

提出一种基于膜优化理论的多目标优化算法,该算法受膜计算的启发,结合膜结构、多重集和反应规则来求解多目标优化问题。为了增强算法的适应能力,采用了遗传算法中的交叉与变异机制,同时在膜中引入外部档案集,并采用非支配排序和拥挤距离方法对外部档案集进行更新操作来提高搜索解的多样性。仿真实验采用标准的KUR和ZDT系列多目标问题对所提出的算法进行测试,通过该算法得出的非支配解集能够较好地逼近真实的Pareto前沿,说明所提算法在求解多目标优化问题上具有可行性和有效性。     

Effect of Different Crowding Agents on the Architectural Properties of the Bacterial Nucleoid-Associated Protein HU

HU is a nucleoid-associated protein expressed in most eubacteria at a high amount of copies (tens of thousands). The protein is believed to bind across the genome to organize and compact the DNA. Most of the studies on HU have been carried out in a simple in vitro system, and to what extent these observations can be extrapolated to a living cell is unclear. In this study, we investigate the DNA binding properties of HU under conditions approximating physiological ones. We report that these properties are influenced by both macromolecular crowding and salt conditions. We use three different crowding agents (blotting grade blocker (BGB), bovine serum albumin (BSA), and polyethylene glycol 8000 (PEG8000)) as well as two different MgCl₂ conditions to mimic the intracellular environment. Using tethered particle motion (TPM), we show that the transition between two binding regimes, compaction and extension of the HU protein, is strongly affected by crowding agents. Our observations suggest that magnesium ions enhance the compaction of HU–DNA and suppress filamentation, while BGB and BSA increase the local concentration of the HU protein by more than 4-fold. Moreover, BGB and BSA seem to suppress filament formation. On the other hand, PEG8000 is not a good crowding agent for concentrations above 9% (w/v), because it might interact with DNA, the protein, and/or surfaces. Together, these results reveal a complex interplay between the HU protein and the various crowding agents that should be taken into consideration when using crowding agents to mimic an in vivo system.