Memories of Fire: Eduardo Galeano and the Geography of Guatemala

In Memory of Fire, a poetic narration of the history of the Americas from pre-Columbian times to the late 20th century, Eduardo Galeano furnishes readers with over 1200 of his trademark vignettes, some 35 of which pertain to Guatemala. Galeano evokes disparate aspects of the geography of Guatemala, past and present, in grounded miniatures of time, place, and episode. His sketches of the experiences of Maya peoples allow us to see them as survivors of three cycles of conquest: (1) conquest by imperial Spain; (2) conquest by local and international capitalism; and (3) conquest by state terror. Composed in the literary mode of creative non-fiction, Memory of Fire serves as an inspirational classroom text, exposing students not only to factual detail but also a powerful artistic imagination.     

Effects of enhanced zinc and copper in drinking water on spatial memory and fear conditioning

Ingestion of enhanced zinc can cause memory impairments and copper deficiencies. This study examined the effect of zinc supplementation, with and without copper, on two types of memory. Rats raised pre- and post-natally on 10 mg/kg ZnCO₃ or ZnSO₄ in the drinking water were tested in a fear-conditioning experiment at 11 months of age. Both zinc groups showed a maladaptive retention of fearful memories compared to controls raised on tap water. Rats raised on 10 mg/kg ZnCO₃, 10 mg/kg ZnCO₃ + 0.25 mg/kg CuCl₂, or tap water, were tested for spatial memory ability at 3 months of age. Significant improvements in performance were found in the ZnCO₃ + CuCl₂ group compared to the ZnCO₃ group, suggesting that some of the cognitive deficits associated with zinc supplementation may be remediated by addition of copper.     

一种基于GPU和内存映射文件的高分辨率遥感图像快速处理方法

高分辨率遥感图像处理经常面临程序执行时间过长和内存空间不足的问题,虽然并行计算技术可以提高遥感图像的处理速度,但是无法降低算法占用的巨大内存空间。为了解决这一问题,本文提出了一种利用CUDA和内存映射文件的高分辨率遥感图像快速处理方法,并以K-Means算法为例进行了实现。其中,CUDA技术可以有效利用GPU强大的并行计算能力,而内存映射文件技术降低了磁盘I/O速度较慢对算法性能的影响。实验结果表明,本文方法比传统K-Means聚类算法计算速度提高了30倍左右,内存使用量降低了90%以上。     

基于人工神经网络的沿海风速多步预测研究

基于气象历史观测资料,将长短期记忆网络LSTM方法和Transformer模型结合提出了混合短期风速多步预测模型BLSTM TRA。以山东半岛南部沿海6个台站为研究区域,通过气象台站观测数据构建数据集。经与2018年ECMWF模式6 h预报结果对比分析,得出如下结论：构建的BLSTM TRA多步预测模型可大幅度降低风速误差,BLSTM TRA的1 h单步预测结果和ECMWF预报模式结果对比,其RMSE平均降低了58.9%,MAE平均降低了63.2%;风速误差和大风统计过程分析发现,BLSTM TRA模型具有一定的抗干扰能力,可以抓住短时大风等敏感信息,对于大风预报结果明显优于ECWMF模式和传统LSTM模型。     

Hoare分类算法的效率改进研究

本文是一篇如何实现改进Hoare分类算法效率的方法研究。文中提出的一个新的快速分类的改进方案优于其它的快速分类算法,其平均分类速度是Hoare原算法的1.6倍左右,额外的内存开销仅为2*[log_2(N/10)]。文中还给出了在IBM-PC/XT微机上对大量随机数排序的实验结果。     

Unstable climates: Exploring the statistical and social constructions of ‘normal’ climate

The idea of climate has both statistical and social foundations. Both of these dimensions of climate change over time: climate, as defined by meteorological statistics, changes for both natural and anthropogenic reasons; and our expectations of future climate also change, as cultures, societies and knowledge evolves. This paper explores the interactions between these different expressions of climate change by focusing on the idea of ‘normal’ climates defined by statistics. We show how this idea came into being in meteorological circles and then review how this idea of climatic normality gets entangled with cultural and psychological processes. Using data from historical and predicted climates in the UK, we illustrate the significance of choosing different baseline ‘normals’ for retrospective and prospective interpretations of climate change. Since the choice of these statistical ‘normals’ reflects cultural, political and psychological preferences and practices as much as scientific ones, we argue that expectations of the climatic future are influenced by social as well as statistical norms. Seeing climate as co-constructed between the psycho-cultural constraints of society and the physical constraints of the material world offers a different way of thinking about the instabilities of climate and the ways we adapt to them.     

Influence of high-pressure processing on the structure and memory effect of synthetic layered double hydroxides

We investigate the structural evolution of synthetic layered double hydroxides (LDH) samples, processed at room temperature and high-pressure (up to 7.7 GPa) in a toroidal chamber with two pressure-transmitting media, lead and graphite, using X-ray diffraction, thermogravimetry and N₂-adsorption isotherms techniques. The X-ray patterns of compacted samples show a decrease in the peak intensities. For both pressure-transmitting media, our samples revealed a reduction of the basal d-spacing for the (003) plane when processed at 7.7 GPa. The expected high-pressure-induced amorphization was not observed. Surprisingly, we find high-pressure processing to have a strong influence on the memory effect of the LDH, due essentially to the reduction of the surface area and pore closing. Even when immersed in water, our samples did not recover the LDH structure, when either calcined at 450°C and compacted at 7.7 GPa, or calcined at 700°C and immediately compacted at 2.5 and 7.7 GPa.     

长短期记忆神经网络(LSTM)模型在低能见度预报中的应用

利用浙江省义乌市2015—2019年逐小时气象观测数据(相对湿度、风速、地气温差、能见度)和空气质量指数(Air Quality Index, AQI)数据, 分析了义乌地区低能见度天气(观测能见度lt; 10 km)的分布特征和气象要素条件。利用长短期记忆神经网络(Long Short Term Memory Neural Network, LSTM)模型对逐小时能见度进行模拟, 分别对比了观测能见度作为输入变量与否的模拟效果; 根据义乌地区低能见度天气条件的特征, 将模拟时段分为三个时期(11月至翌年2月, 3—6月, 7—10月), 对比了分时期模拟的效果; 以及评估了模型的预报步长。结果表明: 高湿、高污染、气温高于地温和低风速是义乌地区低能见度天气的主要特征。LSTM模型对单站能见度有较好的模拟效果, 当输入参数中加入历史观测能见度时, 能大幅提高模拟准确度, 日均能见度模拟结果均方根误差RMSE=0.63 km, 平均绝对误差MAE=0.51 km, 拟合优度R²=0.99;分时期进行模拟能得到更精准的模拟结果。本研究中选用的输入要素在冬季(11月至翌年2月)模拟效果最好, RMSE=2.35 km, MAE=1.46 km, 低能见度均方根误差RMSE_10 km=1.81 km, 低能见度平均绝对误差MAE_10 km=1.13 km, R²=0.83; 3—6月的模拟中, 输入变量中不加AQI模拟效果更好, 这意味着3—6月义乌地区的低能见度天气以雾天气为主导, 加入过多变量并不一定能提高模型准确度; 随着预报步长增大, 模型预报效果变差, 预测步长等于3 h, R²=0.71, 预测结果已不具备实际应用意义。     

Temporal vulnerability in hazardscapes: Flood memory-networks and referentiality along the North Carolina Neuse River (USA)

Social models of population vulnerability to disasters increasingly include the notion that vulnerability has a strong temporal component. While this temporality is typically conceptualized as objective (making vulnerability “dynamic,” “multiscalar,” and/or “historical”), it consistently fails to acknowledge that among stakeholders managing hazardscapes temporality is also a social process in which subjective experience of time may play a role in creating situations of population vulnerability. This paper proposes that the temporal situatedness of a population relative to past hazard events and the quality with which stakeholders engage hazard memory-chains combine to significantly influences its vulnerability to natural hazards. It is proposed that this temporal vulnerability is characterized by shared, population level potential for surprise and can be evaluated by exploration of time-series depth and temporal reference points in historical ecological narratives and documents. Based on ethnohistoric research conducted from 2002 to 2006 in flood-prone eastern North Carolina (USA), it is illustrated how temporal vulnerability was relatively higher in the Neuse River watershed located at the City of Kinston than surrounding watersheds. Due to the combination of factors including the damming of the Neuse River in the 1980s, outdated official floodplain maps, relatively unmonitored floodplain development, the stochastic timing of flood events (placing the last major flood more than a generation away), technological optimism, and turnover of floodplain officials and residents, local stakeholders were seriously misinformed about the space-time risks involved both before and after the disaster of Hurricane Floyd (1999) happened. To deal with this inconsistency, the temporal rarity of Hurricane Floyd as a “500-year event” has been motivated and embraced by many in an effort to continue life-as-is. The paper proposes that the concept of temporal vulnerability is further explored and used as key dimension in the vulnerability sciences.     

铁磁形状记忆合金研究进展与展望（Ⅲ）：应用研究

阐述了铁磁形状记忆合金（Ferromagnetic Shape Memory Alloy,简写为FSMA）在智能材料及其应用领域的优越性。重点介绍了FSMA装置研发和基于FSMA装置的体系分析理论的发展历程和研究现状。仔细分析了各种FSMA装置频率、输出力和最大位移等关键技术指标,讨论了基于电磁学、热力学和力学原理的包含FSMA装置体系的分析理论,指出了各自在面向应用时存在的问题。研究表明,FSMA独特的性能使其具有广阔的应用前景,然而在装置研发和系统理论领域还有待深入。最后指出,更广领域的新型FSMA装置和基于FSMA装置的体系分析理论等问题还有待进一步研究。