Gender bias in the convergence dynamics of the regional homicide rates in Mexico     

《Applied geography (Sevenoaks, England)》2013

The geography of violence in Mexico has changed in recent years because of an explosive increase in regional homicide rates since 2006. This study relies on spatial statistical data analysis to address the issue of convergence in homicide victim rates across Mexican municipalities from 2001 to 2010. Based on the results of spatial panel modeling, we conclude that despite strong regional disparities in murders, municipal-level homicide growth rates display a pattern of convergence with spatial interaction features. This convergent pattern is gender-specific; the homicide growth rates for females show stronger convergence than those for males when local and regional factors are not considered. We postulate that homicide growth dynamics among females more closely follow the predictions of the “modernization hypothesis” than do the dynamics among males. This finding suggests that violence (specifically, homicides) against women in Mexico is driven by underlying factors other than short-term factors, such as drug cartel dynamics, and regional factors, such as local institutions and governments. The data might support the long-established feminist hypothesis that contends that violence against women follows specific dynamics that are different from the dynamics of violence against men.  相似文献   

中国旅游能源消耗与旅游经济增长的关联机制研究——基于空间面板数据模型     

刘佳  赵金金 《云南地理环境研究》2013,(5):1-7

基于地理权重矩阵和经济权重矩阵,运用空间面板数据模型,探讨了2002～2010年中国30个省域旅游能源消耗与旅游经济增长的关联作用机制.研究结果表明：两种空间权重下,中国旅游能源消耗与旅游经济增长均呈现显著的正向空间相关性;旅游能源消耗不仅推动当地旅游经济的增长,还通过空间和经济传导机制对邻近区域的旅游经济产生正向的溢出效应;中国省域旅游能源消耗对旅游经济增长影响中,相对地理位置的影响大于经济差距的影响.  相似文献   

长壁孤岛工作面冲击失稳能量场演化规律   总被引：1，自引：0，他引：1  

王宏伟  姜耀东  高仁杰  刘帅 《岩土力学》2013,34(Z1):479-485

煤矿冲击地压一直是困扰中国煤矿安全的主要问题,而煤矿开采过程中跳采形成的孤岛工作面由于容易产生应力集中,来压强度提高,极容易发生冲击地压。基于唐山矿T2193下孤岛工作面的地质条件,从数值分析的角度研究了煤岩体材料的非均匀性,揭示了孤岛工作面顶板周期来压时煤岩体能量释放的动态特征,分析了工作面前方能量释放激增机制。数值模拟结果显示,长壁工作面回采过程中直接顶的不断垮落造成了老顶悬空距离的不断增大,工作面周期来压时,积聚于老顶岩层内的弹性应变能将瞬间释放,容易引发工作面及巷道的冲击失稳。孤岛工作面由于其特有的矿压显现特征,老顶周期破断时所释放的弹性应变能将更加剧烈,冲击地压势必愈加强烈。孤岛工作面顶底板和煤层的能量释放激增可以作为判断煤岩体冲击失稳的前兆信息。孤岛工作面前方发生冲击破坏的主要原因是由于工作面回采过程中围岩所积聚的大量弹性能在顶板断裂时所伴随的巨大能量释放而造成的。  相似文献   

物流业发展对产业结构优化的实证分析 ——基于空间面板杜宾模型     

高秀丽  孟飞荣 《热带地理》2013,33(6):703-710

目前,我国正处于产业结构优化升级和实现经济发展方式转变的关键时期。物流业作为第三产业的重要组成部分,具有有效降低经济运行成本、提高运作效率和促进产业结构升级的作用。文章首先对省域产业结构合理化和产业结构高级化空间依赖性进行了检验。然后,基于我国1997―2010年30个省级面板数据,通过引入因变量空间滞后项和自变量空间滞后项,构建空间面板杜宾模型,从产业结构合理化和产业结构高级化2个方面分析物流业发展对产业结构优化的影响。研究结果表明：我国产业结构合理化和产业结构高级化存在着显著为正的空间溢出效应,东部、中部和西部地区存在着明显的空间差异;物流业的发展不仅能够显著促进当地产业结构合理化和产业结构高级化进程,而且对邻近地区产业结构优化具有正向的空间溢出效应。最后,文章有针对性地提出了政策建议。  相似文献   

Ecology of Diloma nov Aezelandiae at Portobello,New Zealand     

Sheila J. Logan 《新西兰海洋与淡水研究杂志》2013,47(4):699-714

Some aspects of the biology of Diloma (Fractarmilla) novaezelandiae (Anton) (= Zediloma subrostrata), a soft‐shore trochid gastropod, were investigated in Latham Bay, Portobello, South Island, New Zealand (45° 50’ 25” S, 170° 38’ 30” E). The distribution of D. novaezelandiae during September 1973 to June 1974 was recorded along three transects; pebble distribution, macroalgal cover, grain‐size distribution and organic carbon content in the sediment, range of water salinity, and length of time of exposure to air were also recorded along the transects.

The greatest population density of D. novaezelandiae occurred between 0.8 m and 1.4 m above Chart Datum. The trochid was found to prefer a hard substratum to a soft substratum, and there was a positive correlation of organic content of the sediment with density of D. novaezelandiae. As the population density decreased towards low water the individual shell size increased. Size: weight relationships were calculated and the results showed that dry flesh weight and dry shell weight were both proportional to the cube of the shell diameter.  相似文献   

板格形导管架桩基码头稳定性简化计算方法     

张连丽  王元战  陈飞 《海洋工程》2013,31(5):96-102

板格形导管架桩基码头是适用于深水域软土地基的新型港口与海岸工程结构。该结构由预制的板格形导管架及桩基构成,承载特性和破坏模式复杂。假定码头结构发生倾覆失稳时,转动点位于前桩轴线上,且距导管架底面距离为L。除结构的自身重量外,综合考虑板格形导管架与周围土体间的摩擦力、桩侧摩阻力、桩侧水平土抗力等,对结构进行极限状态受力分析,建立基于假想支撑点的稳定性分析模型,并通过强度折减法进行计算,求取安全系数。以天津滨海沿岸水文地质条件为背景,利用ABAQUS有限元分析软件,建立板格形导管架桩基码头三维弹塑性有限元模型进行稳定性分析,并与简化方法进行比较。结果表明,通过简化计算方法得到的安全系数与有限元结果较为吻合。  相似文献   

低屈服点钢剪切板阻尼器滞回性能试验研究   总被引：4，自引：0，他引：4  

宋中霜  ;李冀龙  ;韩露  ;李惠  ;欧进萍 《地震学刊》2014,(3):289-295

为改善传统滞变型阻尼器在小振动变形时不明显的耗能效果,利用国产低屈服点钢设计了5个剪切板阻尼器（LYPSSP）,并对其进行低周往复循环荷载试验,重点考察阻尼器核心板连接方式、高厚比、十字加劲肋对其滞回性能的影响。研究结果表明：核心板与翼缘板通过熔透焊缝连接与螺栓连接相比,构造简单、可靠度高且易加工;由国产低屈服点钢制作的剪切板阻尼器滞回曲线饱满,耗能性能好,在同一位移级别下循环的滞回曲线基本上重合,稳定性好,并且在整个循环加载过程中,强化现象非常明显,破坏之前也没有出现强度和刚度的突然改变;以P/Py为设计目标时,核心板高厚比越小、面外屈曲越小,滞回曲线就越饱满,耗能性能就越好;根据等效粘滞阻尼器系数和平均耗能指数,能够对阻尼器的耗能性能很好地做出评价。  相似文献   

环境管制对广东省污染产业转移的影响     

沈静  黄双双 《热带地理》2015,35(5):745-752

以广东省为研究对象,首先分析其2000―2010年污染产业转移的变化特征,发现从2006年开始出现由珠三角向非珠三角地区转移的趋势,其中粤北山区接受转移最多,转移趋势明显的行业包括采掘业、非金属制品业,而水电煤气供应业、有色金属行业有轻微的转移趋势。然后采用面板数据模型进行实证研究,以单位工业总产值的SO2排放量为环境管制因子,结果发现总污染产业、采掘业、非金属制品业、水电煤气供应业等产业转移与宽松的环境管制相关。环境管制对广东省污染产业转移起重要作用,中国地方政府强制性的“命令―控制式”的环境管制手段对产业转移的影响大。  相似文献   

Flow around circular and noncircular cylinders by a low-order panel method     

Iskender Sahin  Noriaki Okita 《Ocean Engineering》1998,25(7):529-539

Time-dependent cross-flow was studied around cylinders with circular and noncircular cross-sections. The numerical approach for the analysis was a low-order panel method based on constant source and dipole values along each panel. The method was previously used successfully for several applications, such as calculation of the added mass and damping coefficients. In simulating the viscous time-dependent flow around the cylinder, the time-dependent wake feature of the code was used. For the circular and D-cylinders, the results agreed well with the experiments. Suggestions for improving the results for T-cylinders with angle of attack are included.  相似文献   

柔性仿金枪鱼月牙形尾鳍水动力分析     

成巍苏玉民  秦再白徐玉如 《海洋工程》2004,22(4):73-79

为研究鱼类高速游动机理,以金枪鱼月牙形尾鳍为对象,采用面元法计算分析了其非定常水动力性能。假设尾鳍在横移和摇摆的同时,以某一匀速向前运动,并假设其在弦向和展向以某一给定规律发生变形,以模仿柔性变形。探讨了前进速度、横移和摇摆的幅度、频率及其相位差对柔性尾鳍推进性能的影响,并与做相应运动的刚性尾鳍进行了对比。  相似文献