期刊文献+
共找到11篇文章
< 1 >
每页显示 20 50 100
考虑浮游生物量损失的疏浚船舶选型方法研究 被引量:1
1
作者 宋向群 乔菲菲 +1 位作者 王文渊 张祺 《水道港口》 2016年第2期198-202,共5页
疏浚工程施工产生的悬浮物会对周围海域的浮游生物造成不利影响。文章通过建立近海悬浮物的二维输移扩散模型,研究不同类型、疏浚效率的挖泥船作业中心的悬浮物浓度,结合悬浮物浓度变化量与浮游生物量损失的关系,构建基于浮游生物量损... 疏浚工程施工产生的悬浮物会对周围海域的浮游生物造成不利影响。文章通过建立近海悬浮物的二维输移扩散模型,研究不同类型、疏浚效率的挖泥船作业中心的悬浮物浓度,结合悬浮物浓度变化量与浮游生物量损失的关系,构建基于浮游生物量损失的挖泥船选择模型。以某一基槽疏浚工程为例,当采用抓斗式挖泥船进行疏浚工程施工时,研究施工期间疏浚工程对浮游生物量损失的影响,在仅考虑浮游生物量损失的条件下,为疏浚工程施工选用合理疏浚效率的挖泥船。研究结果表明,在施工工期允许的条件下应选择疏浚效率较小的挖泥船,以减少疏浚悬浮物对浮游生物的影响。 展开更多
关键词 疏浚工程 悬浮物 挖泥船选择 生物量损失
下载PDF
台风“山竹”对深圳城市绿地及生物量的影响 被引量:5
2
作者 田韫钰 周伟奇 +2 位作者 钱雨果 郑重 潘雪莲 《生态学报》 CAS CSCD 北大核心 2020年第8期71-80,共10页
台风是影响沿海城市绿地生态系统最主要、最频繁的自然干扰因子。2018年9月的台风"山竹"以强台风等级袭击深圳,陆地最大阵风达46.5 m/s(15级)。以深圳市区绿地(公园绿地、居民区绿地、行道树)中的乔木为研究对象,通过灾后实... 台风是影响沿海城市绿地生态系统最主要、最频繁的自然干扰因子。2018年9月的台风"山竹"以强台风等级袭击深圳,陆地最大阵风达46.5 m/s(15级)。以深圳市区绿地(公园绿地、居民区绿地、行道树)中的乔木为研究对象,通过灾后实地调研,采用相关统计方法以及生物量评估方法,探讨了台风"山竹"对深圳市区绿地的影响。结果表明:(1)深圳市区调查树木受损比例高达21.4%,其中以轻度受损(枝干折断)为主;市区树冠生物量总量较台风之前下降了8.44%。(2)南部地区受损程度明显高于内陆,东南地区受损程度高于西北地区;福田区、龙岗区以及坪山新区受损情况最为严重,受损树木比例均超过30%。中东部树冠生物量损失程度高于西部地区。(3)公园绿地受损最为严重,居民区绿地的受损情况最轻。(4)行道树中黄金榕、腊肠树受损比例均超过50%,而棕榈科植物受损程度较轻。研究结果可为深圳市抗风树种的选择、不同类型绿地针对台风的减灾防灾策略提供科学依据。 展开更多
关键词 台风灾害 城市绿地 生物量损失 抗风树种 深圳
下载PDF
高原鼠兔对高寒草甸植物群落生物量的影响 被引量:23
3
作者 严红宇 张毓 +3 位作者 赵建中 许庆民 李里 刘伟 《兽类学报》 CAS CSCD 北大核心 2013年第4期333-343,共11页
2010年和2011年8月在青海省果洛州矮嵩草草甸,采用样方法测定了不同密度高原鼠兔栖息地内杂草斑和秃斑植物群落特征及地上生物量的变化。结果表明:2010年与2011年相比,相同高原鼠兔密度的栖息地内杂草斑和秃斑植物总盖度、平均高度和总... 2010年和2011年8月在青海省果洛州矮嵩草草甸,采用样方法测定了不同密度高原鼠兔栖息地内杂草斑和秃斑植物群落特征及地上生物量的变化。结果表明:2010年与2011年相比,相同高原鼠兔密度的栖息地内杂草斑和秃斑植物总盖度、平均高度和总地上生物量差异不显著,但同一年份不同密度栖息地间差异显著。高原鼠兔低、中、高密度栖息地植物总盖度、平均高度和总地上生物量显著低于无鼠兔对照组(P<0.05),不同密度间无明显变化规律。低、中、高密度栖息地的莎草、禾草和豆科植物盖度、平均高度和地上生物量显著低于无鼠兔对照组(P<0.05),秃斑上豆科植物消失;杂类草平均高度在低密度栖息地和无鼠兔对照组显著高于中、高密度栖息地(P<0.05),盖度和地上生物量对照组最小,随高原鼠兔密度增加呈增加趋势。2010年和2011年,高原鼠兔低、中、高密度栖息地内杂草斑面积分别占样地面积的4.0%、4.3%、13.3%和3.8%、4.3%、11.0%,秃斑面积分别占样地面积的0.2%、2.6%、4.0%和0.2%、2.2%、3.4%;植物损失地上生物量分别为110.84 kg/hm2、203.18 kg/hm2、431.58 kg/hm2和107.67 kg/hm2、189.46 kg/hm2、365.72 kg/hm2。高原鼠兔的密度(x)与植物损失地上生物量(y)之间存在对数曲线关系,说明高原鼠兔的活动显著降低了植物总盖度、平均高度和总地上生物量,同时也改变了植物功能群组成。随高原鼠兔密度增加,栖息地内杂草斑、秃斑的面积和植物损失地上生物量呈增加趋势。 展开更多
关键词 高原鼠兔 杂草斑 秃斑 损失生物量 植物群落
下载PDF
浙江省1991~2006年森林火灾释放黑碳量的估算 被引量:13
4
作者 杨国福 江洪 +2 位作者 余树全 周国模 贾伟江 《生态学报》 CAS CSCD 北大核心 2009年第5期2612-2621,共10页
黑碳气溶胶不仅造成环境污染危害人的健康,同时通过吸收太阳和大气辐射产生的辐射强迫对全球和区域产生影响,成为影响全球变暖的仅次于CO2的重要成分。在全球变暖及大气中CO2浓度不断升高的趋势下,各国开始采用造林再造林来减缓全球变... 黑碳气溶胶不仅造成环境污染危害人的健康,同时通过吸收太阳和大气辐射产生的辐射强迫对全球和区域产生影响,成为影响全球变暖的仅次于CO2的重要成分。在全球变暖及大气中CO2浓度不断升高的趋势下,各国开始采用造林再造林来减缓全球变暖的趋势,随着森林面积和林内生物量的不断增加,以及森林火灾的频发,林火带来的黑碳排放量也不容忽视。然而在世界上大部分地区,这方面的工作却很少被人所关注。根据1991~2006年浙江省森林火灾统计资料和浙江省各种森林类型地上生物量的数据,计算出了浙江省每年的森林火灾导致的生物量损失量。同时采取释放因子法,对1991~2006浙江省每年森林火灾释放的黑碳量进行了估算。其中1995年和2000年森林火灾释放的黑碳总量分别是38.4、97.2 t,占整个浙江省黑碳释放总量中的比重分别是0.12%、0.17%,对于区域大气质量有一定的影响。 展开更多
关键词 黑碳 森林火灾 生物量损失
下载PDF
转Btcry1Ab基因水稻对稻田弹尾虫种群数量的影响 被引量:13
5
作者 白耀宇 蒋明星 +1 位作者 程家安 王敦 《应用生态学报》 CAS CSCD 北大核心 2006年第5期903-906,共4页
以转Btcry1Ab基因水稻克螟稻1号(KMD1)和克螟稻2号(KMD2)及其亲本非转基因水稻秀水11(XS11)为材料,于2003年9月和翌春4月,调查了KMD1和KMD2对水稻灌浆期和收割后休田期稻田土表落叶层中弹尾虫种群数量的影响.结果表明,KMD植株表达的cry... 以转Btcry1Ab基因水稻克螟稻1号(KMD1)和克螟稻2号(KMD2)及其亲本非转基因水稻秀水11(XS11)为材料,于2003年9月和翌春4月,调查了KMD1和KMD2对水稻灌浆期和收割后休田期稻田土表落叶层中弹尾虫种群数量的影响.结果表明,KMD植株表达的cry1Ab杀虫蛋白可在稻田环境中残留160d以上;在水稻灌浆期采用吸虫器法在稻田落叶层中采集到灰橄榄长角跳虫(Entomobrya griseoolivata)和钩圆跳虫(Bourletiella christianseni)等2种弹尾虫,其中灰橄榄长角跳虫在KMD1和KMD2稻田中的种群密度显著高于XS11稻田;在水稻收割后休田期采用网袋法采集到灰橄榄长角跳虫、钩圆跳虫、球角跳虫(Hypogastrura matura)和等节跳虫(Isotoma monochaeta)等4种弹尾虫,其中转Bt基因水稻稻田中的灰橄榄长角跳虫和球角跳虫的种群密度显著高于XS11稻田,且其植株组织残体生物量损失率显著高于XS11. 展开更多
关键词 转BT基因水稻 弹尾虫 CRY1AB杀虫蛋白 种群 生物量损失
下载PDF
辽宁山区桓仁至永陵高速公路建设对原有植被损毁评价
6
作者 胡晋茹 孟煜康 张晓峰 《国际沙棘研究与开发》 2014年第3期39-42,共4页
笔者选取辽宁山区桓仁至永陵高速公路作为研究对象,用生物量及绿当量方法估测了项目建设区的植被破坏程度,以及施工结束后绿化工程的补偿作用,希望可为其他地区公路建设项目生态环境影响定量化评价提供参考。
关键词 高速公路 绿当量 生物量损失
下载PDF
Nutritional status changes in patients with advanced non-small cell lung cancer receiving first-line chemotherapy 被引量:1
7
作者 Wei Sun Shunfang Liu +1 位作者 Ping Peng Dongbo Liu 《Oncology and Translational Medicine》 2018年第2期54-57,共4页
Objective This study aimed to assess the real-life nutritional status changes and gastrointestinal symptoms in patients with advanced non-small cell lung cancer(NSCLC) receiving chemotherapy.Methods A total of 104 pat... Objective This study aimed to assess the real-life nutritional status changes and gastrointestinal symptoms in patients with advanced non-small cell lung cancer(NSCLC) receiving chemotherapy.Methods A total of 104 patients with metastatic NSCLC receiving first-line chemotherapy were included in this study. Unintentional weight loss, body mass index(BMI) changes, and gastrointestinal symptoms were recorded and evaluated. Biochemical parameters [hemoglobin(Hb) and albumin levels] were compared before and after two chemotherapy cycles using SPSS software.Results Of these patients, 65.38%(68/104) experienced unintentional weight loss, whereas 30.77% and 12.5% presented with ≥ 5% and ≥ 10% degrees of weight loss, respectively, within 6 months before first-line chemotherapy was administered. Then, 48.08%(50/104) of the patients experienced unintentional weight loss after two chemotherapy cycles. The mean body weight after chemotherapy was 61.47 ± 10.37 kg, which was significantly decreased relative to that before chemotherapy(P < 0.05). The mean BMI after chemotherapy was 22.66 ± 3.34 kg/m^2, which was also significantly diminished with respect to that during the previous chemotherapy cycle(P < 0.05). The most common gastrointestinal symptoms reported among all the study patients were anorexia(80/104, 76.92%), nausea(53/104, 50.96%), constipation(49/104, 47.12%), vomiting(48/104, 46.15%), taste disorders(40/104, 38.46%), and early satiety(32/104, 30.77%). The mean Hb levels after chemotherapy were 117.06 ± 16.67 g/L, which were significantly lower than those before chemotherapy(132.73 ± 16.42 g/L)(P < 0.05). No significant difference was noted between the mean albumin levels before and after chemotherapy(38.29 ± 4.22 g/L vs 38.17 ± 4.54 g/L; P = 0.798). Conclusion Weight loss history, gastrointestinal symptoms, and Hb level decreases are determinant factors of nutritional status in patients with advanced NSCLC and must be included in the screening, evaluation, and treatment of lung carcinoma. 展开更多
关键词 lung cancer gastrointestinal symptoms weight loss CHEMOTHERAPY HEMOGLOBIN ALBUMIN
下载PDF
Status and Prospects of Certification Procedure of Novel Pesticides against Major Cocoa Pests Sahlbergella Sngularis and Phytophthora Megakarya in Nigeria
8
作者 Evarestus Uche Asogwa Feyisara Abiodun Okelana Lelia Nkechinyere Dongo Olutayo Akanbi Fademi 《Journal of Life Sciences》 2011年第6期477-482,共6页
Sahlbergella singularis (brown cocoa mirid) is responsible for over 30% yield loss of cocoa, while Phytophthora megakarya (causal organism of black pod disease) causes between 70-100% yield loss of cocoa in Nigeri... Sahlbergella singularis (brown cocoa mirid) is responsible for over 30% yield loss of cocoa, while Phytophthora megakarya (causal organism of black pod disease) causes between 70-100% yield loss of cocoa in Nigeria. In all the Nigerian cocoa agroecological zones, the use of pesticides still remains an important component among the strategies for effective control of major insect pests and diseases of cocoa. The Cocoa Research Institute of Nigeria (CRIN), has the national mandate to evaluate and recommend novel pesticides from various groups that fall within the European-Union standards for use on cocoa farms in Nigeria. Such pesticides usually undergo rigorous testing spanning over 3 years to determine correct dose necessary to produce toxic reactions to the targeted pests without any adverse effects on the environment, man and non-target organisms. The screening exercise for candidate pesticides starts with confirmatory test of the constituent active ingredient, laboratory bioassay, phytotoxicity test, first, second and third year field evaluation and residue analysis of beans harvested from the treated plots. This paper critically examines these standard procedures, which must be followed judiciously for novel pesticides certification and recommendation for use in Nigeria. 展开更多
关键词 Cocoa protection cocoa pests PESTICIDES concentration regulations.
下载PDF
Effect of Natural Infection with Onion Yellow Dwarf Virus (OYDV) on Yield of Onion and Garlic Crops in Egypt
9
作者 Salah Elnagar Mohamed Abdel-Kader El-Sheikh Abeer Salah E1-Deen Abd E1-Wahab 《Journal of Life Sciences》 2011年第8期634-638,共5页
Present work highlights, first time in Egypt, the impact of OYDV infection on crops production. Plants grown in the field were individually labelled as either apparently healthy or diseased and were marked for harvest... Present work highlights, first time in Egypt, the impact of OYDV infection on crops production. Plants grown in the field were individually labelled as either apparently healthy or diseased and were marked for harvesting. The percentage of yield loss due to viral infection was determined, on the basis of the average yield parameters of the healthy plant. The natural infection with OYDV in onion and garlic fields resulted in a substantial reduction in pseudo-stem length, number of leaves, plant weight and weight of bulb as well as number and weight of cloves. Results clearly indicate the impact of natural infection with OYDV on the crop yield of infected onion and garlic plants in comparison with the virus-free (uninfected) ones. The largest reduction in the yield of infected plants occurred in Chinese garlic (Seds40) followed by (Baladi) garlic and onion Giza 20. This information suggests that measures have to be taken to prevent natural infection with OYDV into and within onion and garlic fields in order to avoid yield loss. 展开更多
关键词 Onion yellow dwarf virus (OYDV) yield reduction ONION garlic.
下载PDF
The Time-Effect Relationship of Central Action in Acupuncture Treatment for Weight Reduction 被引量:2
10
作者 赵玫 刘志诚 +1 位作者 苏静 王友京 《Journal of Traditional Chinese Medicine》 SCIE CAS CSCD 2000年第1期26-29,共1页
Purpose: To study the time-effect relationship of action of acupuncture on the satiety center of ventromedial nucleus of hypothalamus (VMH) in rats with experimental obesity. Methods: Microelectrode recording method o... Purpose: To study the time-effect relationship of action of acupuncture on the satiety center of ventromedial nucleus of hypothalamus (VMH) in rats with experimental obesity. Methods: Microelectrode recording method of nerve cells and stereotaxic technique for brain were adopted with discharge frequency (Hz/s) of nerve impulse in VMH as the index, and the time-effect of acupuncture action in different periods between groups were observed. Results: Electric activity in acupuncture group was higher than that in the obesity model group (P<0.001) and the normal group (P<0.01) respectively, and the curve of acupuncture action within 2 hours showed irregular fluctuation. Conclusion: Acupuncture can increase excitability of the satiety center, with a better long-term effect. 展开更多
关键词 Acupuncture Therapy ELECTROACUPUNCTURE Weight Loss ANIMALS ELECTROPHYSIOLOGY Male Obesity Random Allocation RATS Rats Sprague-Dawley Time Factors Ventromedial Hypothalamic Nucleus
全文增补中
Effects of Biochars and Other Organic Soil Amendments on Plant Nutrient Availability in an Ustoxic Quartzipsamment 被引量:2
11
作者 Thippawan KONGTHOD Suphicha THANACHIT +1 位作者 Somchai ANUSONTPORNPERM Wanpen WIRIYAKITNATEEKUL 《Pedosphere》 SCIE CAS CSCD 2015年第5期790-798,共9页
A sandy soil, Nampong soil (classified as Ustoxic Quartzipsamment), was incubated under controlled condition i) to compare the mineralization of major plant nutrients derived from different types of biochars and ot... A sandy soil, Nampong soil (classified as Ustoxic Quartzipsamment), was incubated under controlled condition i) to compare the mineralization of major plant nutrients derived from different types of biochars and other organic soil amendments; ii) to examine their effects on soil properties and plant nutrient availability; and iii) to evaluate the plant nutrient losses in leachate from the rooting zone of soil incorporated with the different amendments. The experiment was arranged in a completely randomized design with 3 replications. Five treatments of soil amendments used were cassava stem base biochar (CSB), rice husk biochar (RHB), chicken manure (CM), compost (CP), and no amendment application (control). The RHB treatment released the highest amounts of mineralized NO^-N, available P and K (2.30-17.26, 5.50-42.90 and 43.00-187.63 mg kg-1, respectively) while the CM treatment releasing the highest NH4+-N in the range of 1.86-53.67 mg kg-1. The CSB and RHB treatments showed better continuity of mineralization of nutrients than the treatments of CM and CP, particularly in the case of the CSB treatment. In the soil column incubation experiment, the amounts of NH4+-N and NO3-N in all treatments barely changed on Day 1 to Day 30 of incubation and then the amounts increased markedly on Day 60. On Day 601 the RHB treatment contained a very high amount of NO3--N (〉 250 mg kg-1). This suggests that N would become more available 30 d after the incorporation. The CM treatment gave the highest amounts of organic matter and available P in the ranges of 4.64-8.94 g kg-1 and 14.41-36.33 mg kg-1, respectively, during the 60-d column incubation. The CSB treatment tended to have higher available K throughout the measuring period. The NO3--N was leached from the soil column quite quickly on Day 1 of incubation while the loss of NH^-N decreased slightly from Day 1 until the end of the measurement. The amounts of P and K losses varied with the type of soil amendments, and the pattern of the loss was irregular. 展开更多
关键词 cassava stem base biochar chicken manure COMPOST MINERALIZATION rice husk biochar sandy soil
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部