硫铁矿冶炼区不同土地利用方式及土壤类型对重金属迁移的影响

为探讨硫铁矿冶炼区不同土地利用方式和土壤类型对重金属元素迁移的影响,采集了毕节市林口废弃硫铁矿冶炼厂内耕地砂壤土及附近林地石灰土表层和深层样共40组。室内测试土壤理化指标Pb、Zn、Cd全量和有效态含量,并对重金属元素含量的水平和垂直分布特征及重金属元素含量的相关性进行了讨论。结果表明:土壤中Pb和Zn的含量均符合土壤环境质量二级标准值,耕地表层土壤Cd含量是贵州省农业土壤背景值的7倍。土壤Cd有效态含量占全量的比值最大,而Pb和Zn有效态含量占全量的比值差别较小。耕地砂壤土Zn和Cd的全量随剖面深度的增加表现为先增大后减小,Pb呈减少的趋势;Pb和Zn的有效态含量随剖面深度的增加而减少,Cd有效态含量呈波动变化。林地石灰土中Pb、Zn、Cd的全量和有效态含量均随剖面深度的增加而减少,且Pb、Zn、Cd全量之间及全量与有效态含量之间都具有显著的正相关关系,而在耕地中各元素的相关性不明显。土壤频繁的扰动和偏酸性的环境有利于重金属垂向迁移。

CO2浓度梯度对两种岩溶微藻碳酸酐酶活性的影响

以经岩溶水驯化的小球藻(Chlorella vulgaris)和喜钙念珠藻(Nostoc calcicola Breb.)为实验对象,在封闭体系中用Willbur和Anderson方法比较研究两种不同微藻在不同CO_2浓度下碳酸酐酶活性变化情况。结果表明:在低于3%CO_2浓度的环境中岩溶微藻可通过快速调节自身碳酸酐酶活性来应对CO_2升高带来的生境影响,在影响最大的2.5%的环境下小球藻与喜钙念珠藻碳酸酐酶活性分别提高了1.46倍和2.12倍;岩溶微藻应对CO_2浓度增大带来的pH下降有着重要的恢复作用,随培养时间增长培养环境中的pH得到恢复;随着CO_2浓度的增大,岩溶因子对碳酸酐酶有着重要的影响;培养48h时Ca^(2+)与喜钙念珠藻碳酸酐酶的相关性最高,而电导率(EC)与小球藻碳酸酐酶相关程度最高。

The role of exercise in brain DNA damage

Cells are constantly subjected to cytotoxic and genotoxic insults resulting in the accumulation of unrepaired damaged DNA,which leads to neuronal death.In this way,DNA damage has been implicated in the pathogenesis of neurological disorders,cancer,and aging.Lifestyle factors,such as physical exercise,are neuroprotective and increase brain function by improving cognition,learning,and memory,in addition to regulating the cellular redox milieu.Several mechanisms are associated with the effects of exercise in the brain,such as reduced production of oxidants,up-regulation of antioxidant capacity,and a consequent decrease in nuclear DNA damage.Furthermore,physical exercise is a potential strategy for further DNA damage repair.However,the neuroplasticity molecules that respond to different aspects of physical exercise remain unknown.In this review,we discuss the influence of exercise on DNA damage and adjacent mechanisms in the brain.We discuss the results of several studies that focus on the effects of physical exercise on brain DNA damage.

Determination of the Stabilization Time of the Solution-Air Interface for Aggregates Formed by NaC in Mixtures with SDS and PEO, Investigated by Dynamic Surface Tension Measurements

The properties of mixtures of poly (ethylene oxide) (PEO) and mixed micelles formed from sodium cholate (NaC) and sodium dodecyl sulfate (SDS) in tris/HCl buffered solutions at pH 9.00 were investigated by measuring the mean surface tension. The variation in the superficial tension as a function of the time after formation of solutions containing PEO and NaC was characterized by monitoring the time required for the system to reach equilibrium between the micellar and aqueous phases. These results could serve as a reference for the minimum aging time required for solutions before any surface tension measurements can be performed.

Sustainability and Market Orientation in the Brazilian Beef Chain

The demand for natural resources, energy and food facing the contemporary perception of sustainability is imposing challenges to the productive sectors in accordance with market guidelines. In this context, the Brazilian agribusiness seeks to maintain external competitiveness and to satisfy growing domestic demands. In beef production, this competitiveness pervades traceability, food safety and sustainability. This article aims to identify the sustainability state of the art in agribusiness and characterize it within the Brazilian beef chain. Descriptive methodology, combining a literature review and a documentary data survey were adopted. An outline of the dimensions of agribusiness sustainability, drawn from benchmark practices, indicates that environmental, social and technological demands have become part of the industry＇s agenda. The data for beef cattle point to a growth in production but demonstrate that expansion has occurred in areas of environmental tension, which creates a demand for sustainability in the beef chain. A table of guidelines for sustainability demonstrates that although perceptions are not yet harmonized among the links in the whole beef chain, many of the technological guidelines for sustainable production may increase the producer＇s economic efficiency. In the Brazilian case, the increment of initiatives and dissemination of sustainable practices among the beef chain is desirable to provide a coordinated response of production, processing and distribution organizations facing market opportunities for sustainable livestock.

Clinical evidence of human pathogens implicated in Alzheimer’s disease pathology and the therapeutic efficacy of antimicrobials:an overview

A wealth of pre-clinical reports and data derived from human subjects and brain autopsies suggest that microbial infections are relevant to Alzheimer’s disease(AD).This has inspired the hypothesis that microbial infections increase the risk or even trigger the onset of AD.Multiple models have been developed to explain the increase in pathogenic microbes in AD patients.Although this hypothesis is well accepted in the field,it is not yet clear whether microbial neuroinvasion is a cause of AD or a consequence of the pathological changes experienced by the demented brain.Along the same line,the gut microbiome has also been proposed as a modulator of AD.In this review,we focus on human-based evidence demonstrating the elevated abundance of microbes and microbe-derived molecules in AD hosts as well as their interactions with AD hallmarks.Further,the direct-purpose and potential off-target effects underpinning the efficacy of anti-microbial treatments in AD are also addressed.

南京明城墙序贯PSInSAR形变估计

针对永久散射体PSInSAR(Persistent Scatterer SAR Interferometry)算法流程的局限性,本文立足差分雷达干涉预处理和时序微变反演性能提升,提出了一种基于优化解空间的PSInSAR序贯处理算法。该算法能够实现新SAR影像无缝嵌入,避免时序PSInSAR整体数据处理流程溯源,实现微变参数的准实时更新。研究以南京明城墙文化遗产及其200 m缓冲区赋存环境为示范,基于2015-01—2018-02的32景降轨Cosmo-SkyMed条带影像,开展传统PSInSAR方法与优化解空间PSInSAR序贯方法形变反演与性能对比研究。结果表明,基于解空间优化的PSInSAR序贯方法简化了差分干涉流程,通过解空间搜索机制和结构改进,降低了算法时空复杂度,实现了未知参数求解约10倍效率提升。通过形变场精度交叉验证,发现两种方法形变估计结果吻合(总体误差在0—1 mm),证实了PSInSAR序贯方法的有效性与可靠性,并揭示其在遥感大数据时代文化遗产高精度、准实时微变监测中的应用潜力。

中国南方喀斯特

核心价值概述 中国南方喀斯特世界自然遗产包括7个喀斯特遗产组成地，分布在4个省，分别是石林喀斯特、荔波喀斯特、武隆喀斯特、桂林喀斯特、施秉喀斯特、金佛山喀斯特、环江喀斯特。