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黑尾叶蝉Nephotettix cincticeps Uhler是稻区重要害虫,对它寻找有效的防治措施是当务之急。喷洒药剂抑制害虫繁殖是综合防治中一个重要环节。黑尾叶蝉对1605有自然抗性。马拉松防治效果虽好,但我省供应量尚不能满足实际需要,长期使用也可能引起抗性(尾崎幸三郎等,1965、1967;Kojina等,1963;Toskikezu,1972)。有机磷杀虫剂“甲胺磷”[O,S-二甲基-胺基硫代磷酸酯,下文中简称“T”]经二、三年全国药效试验证实它防治黑色叶蝉有显著效果。我校自1972年开始用化学测定方法和同位素示踪法研究它在田间的残留动态。现将化学测定二年来的研究结果总结如下。 “甲胺磷”超微量化学测定技术已有介绍(Backman et al.,1969)。我们曾用附有氢 相似文献
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半干旱黄土丘陵区多元化草地建设技术研究 总被引:5,自引:1,他引:4
针对黄土丘陵区草地退化,水土流失严重,草地畜牧业生产力低等问题,于1995~2002年在半干旱黄土丘陵区的安塞县进行了多元化草地建设试验研究。引种、驯化生态经济型优良草种20余种(包括品种、类型),建设高产、优质单播及混播人工草地和利用耐牧草种改良天然草地,为在半干旱黄土丘陵区充分利用水土资源,改良大面积天然草地,提高其生产力和生态、经济效益,及在退耕坡地建设人工草地,为促进农牧业可持续发展提供物质基础及科学依据。 相似文献
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Mitochondrial dysfunction is a hallmark of beta-amyloid (Aβ)-induced neurotoxicity in Alzheimer's disease (AD), and is considered an early event in AD pathology. Diammonium glycyrrhizinate (DG), the salt form of Glycyrrhizin, is known for its anti-inflammatory effects, resistance to biologic oxidation and membranous protection. In the present study, the neuroprotective effects of DG on Aβ(1-42)-induced toxicity and its potential mechanisms in primary cortical neurons were investigated. Exposure of neurons to 2 μM Aβ(1-42) resulted in significant viability loss and cell apoptosis. Accumulation of reactive oxygen species (ROS), decreased mitochondrial membrane potential, and activation of caspase-9 and caspase-3 were also observed after Aβ(1-42) exposure. All these effects induced by Aβ(1-42) were markedly reversed by DG treatment. In addition, DG could alleviate lipid peroxidation and partially restore the mitochondrial function in Aβ(1-42)-induced AD mice. DG also significantly increased the PGC-1α expression in vivo and in vitro, while knocking down PGC-1α partially blocked the protective effects, which indicated that PGC-1α contributed to the neuroprotective effects of DG. Furthermore, DG significantly decreased the escape latency and search distance and increased the target crossing times of Aβ(1-42)-induced AD mice in the Morris water maze test. Therefore, these results demonstrated that DG could attenuate Aβ(1-42)-induced neuronal injury by preventing mitochondrial dysfunction and oxidative stress and improved cognitive impairment in Aβ(1-42)-induced AD mice, indicating that DG exerted potential beneficial effects on AD. 相似文献
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Many terns (Laridae) from the northern hemisphere overwinter in Australia, but they are rarely covered comprehensively in
bird counts in Australian coastal waterways. We conducted censuses over 3 years on terns in an increasingly popular recreational
waterway at the northern end of Moreton Bay, known as Caloundra sandbanks, to provide the first overview of the relative abundance
of non-breeding tern species on estuary-type sandbanks in Australia. The maximum number of birds counted was > 43,000, of
which over 90% belonged to six species of terns. The most abundant tern species was the common tern Sterna hirundo longipennis which reached > 38,000 in one Austral summer. Other northern-breeding migrant terns were the white-winged black tern Chlidonias leucopterus ( > 17,000) and the little tern S. albifrons sinensis ( >11,000), which also breeds in Australia. These migrant terns arrived at Caloundra sandbanks at around late-October and
a vast majority had departed by mid-April. Numbers were generally highest from late-December through to early-April. An additional
three Australian-breeding terns of smaller population sizes frequented the sandbanks. Density of terns using the habitats
could reach a peak of 600 ha−1 during the warmer months of the year, coinciding with peak human recreational activities. In light of the results, Caloundra
sandbanks should be regarded as an Area of International Importance based on criteria contained in the Ramsar Convention.
The situation at Caloundra sandbanks presents challenges to recreational and tourism issues, requiring review of traditional
government priorities in the conservation of wetlands based primarily on waders. 相似文献
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Complex histories of repeated gene flow in Cameroon crater lake cichlids cast doubt on one of the clearest examples of sympatric speciation 下载免费PDF全文
Christopher H. Martin Joseph S. Cutler John P. Friel Cyrille Dening Touokong Graham Coop Peter C. Wainwright 《Evolution; international journal of organic evolution》2015,69(6):1406-1422
One of the most celebrated examples of sympatric speciation in nature are monophyletic radiations of cichlid fishes endemic to Cameroon crater lakes. However, phylogenetic inference of monophyly may not detect complex colonization histories involving some allopatric isolation, such as double invasions obscured by genome‐wide gene flow. Population genomic approaches are better suited to test hypotheses of sympatric speciation in these cases. Here, we use comprehensive sampling from all four sympatric crater lake cichlid radiations in Cameroon and outgroups across Africa combined with next‐generation sequencing to genotype tens of thousands of SNPs. We find considerable evidence of gene flow between all four radiations and neighboring riverine populations after initial colonization. In a few cases, some sympatric species are more closely related to outgroups than others, consistent with secondary gene flow facilitating their speciation. Our results do not rule out sympatric speciation in Cameroon cichlids, but rather reveal a complex history of speciation with gene flow, including allopatric and sympatric phases, resulting in both reproductively isolated species and incipient species complexes. The best remaining non‐cichlid examples of sympatric speciation all involve assortative mating within microhabitats. We speculate that this feature may be necessary to complete the process of sympatric speciation in nature. 相似文献
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Karen Harrison Dening Michael King Louise Jones Victoria Vickestaff Elizabeth L. Sampson 《PloS one》2016,11(7)
MethodsA cross-sectional study interviewing 60 dyads (a person with early dementia and preserved capacity and their family carer) each completing a modified LSPQ. We assessed how closely carers’ choices resembled the PWD’s preferences for treatment in three proposed health states: the here and now; severe stroke with coma; terminal cancer. Agreement between the PWD and their family carer responses was assessed using Kappa and Prevalence-Adjusted Bias-Adjusted Kappa (PABAK) statistics. We examined whether carer burden and distress, and relationship quality, influenced agreement.ResultsIn interviews PWD were able to indicate their treatment preferences across all three scenarios. In the here-and-now most wanted antibiotics (98%), fewer cardio-pulmonary resuscitation (CPR) (50%) and tube feeding (47%). In severe stroke and coma antibiotics remained the more preferred treatment (88%), followed by CPR (57%) and tube feeding (30%). In advanced cancer PWD expressed lower preferences for all treatments (antibiotics 68%; CPR 50%; tube feeding 37%). Carers’ choices were similar to the PWDs’ preferences in the here-and-now (71% (k = 0.03; PABAK = 0.4) with less agreement for future hypothetical health states. In severe stroke and coma carers tended wrongly to suggest that the PWD preferred more intervention (antibiotic, 67%; k = -0.022; PABAK = -0.60; CPR, 73%; k = 0.20; PABAK = -0.20, tube feeding, 66%; k = 0.25; PABAK = -0.12). In advanced cancer the agreement between PWD and carers was low (antibiotics; k = -0.03; PABAK = -0.52; CPR, k = -0.07; PABAK = -0.45; tube feeding; k = 0.20; PABAK = -0.22). However, both PWD and carers showed marked uncertainty about their preferences for end of life treatment choices. Relationship quality, carer distress and burden had no influence on agreement.ConclusionsThis study is the first to have used the LSPQ with PWD in the UK to consider treatment options in hypothetical illness scenarios. Key finding are that family carers had a low to moderate agreement with PWD on preferences for end of life treatment. This underscores how planning for care at the end of life is beset with uncertainty, even when the carer and PWD perceive the care-giving/receiving relationship is good. Families affected by dementia may benefit from early and ongoing practical and emotional support to prepare for potential changes and aid decision making in the context of the realities of care towards the end of life. 相似文献
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Shujun Nie Bo Wang Haiping Ding Haijian Lin Li Zhang Qigui Li Yujiao Wang Bin Zhang Anping Liang Qi Zheng Hui Wang Huayang Lv Kun Zhu Minghui Jia Xiaotong Wang Jiyuan Du Runtai Zhao Zhenzhen Jiang Caina Xia Zhenghao Qiao Xiaohu Li Boyan Liu Hongbo Zhu Rong An Yucui Li Qian Jiang Benfang Chen Hongkai Zhang Dening Wang Changxiao Tang Yang Yuan Jie Dai Jing Zhan Weiqiang He Xuebo Wang Jian Shi Bin Wang Min Gong Xiujing He Peng Li Li Huang Hui Li Chao Pan Hong Huang Guangsheng Yuan Hai Lan Yongxin Nie Xinzheng Li Xiangyu Zhao Xiansheng Zhang Guangtang Pan Qingyu Wu Fang Xu Zhiming Zhang 《The Plant journal : for cell and molecular biology》2021,108(1):40-54
Maize is an important crop worldwide, as well as a valuable model with vast genetic diversity. Accurate genome and annotation information for a wide range of inbred lines would provide valuable resources for crop improvement and pan-genome characterization. In this study, we generated a high-quality de novo genome assembly (contig N50 of 15.43 Mb) of the Chinese elite inbred line RP125 using Nanopore long-read sequencing and Hi-C scaffolding, which yield highly contiguous, chromosome-length scaffolds. Global comparison of the RP125 genome with those of B73, W22, and Mo17 revealed a large number of structural variations. To create new germplasm for maize research and crop improvement, we carried out an EMS mutagenesis screen on RP125. In total, we obtained 5818 independent M2 families, with 946 mutants showing heritable phenotypes. Taking advantage of the high-quality RP125 genome, we successfully cloned 10 mutants from the EMS library, including the novel kernel mutant qk1 (quekou: “missing a small part” in Chinese), which exhibited partial loss of endosperm and a starch accumulation defect. QK1 encodes a predicted metal tolerance protein, which is specifically required for Fe transport. Increased accumulation of Fe and reactive oxygen species as well as ferroptosis-like cell death were detected in qk1 endosperm. Our study provides the community with a high-quality genome sequence and a large collection of mutant germplasm. 相似文献
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