不同类型植物净光合速率的日变化及其对光合有效辐射响应数学模型研究

以金银花、马铃薯和苎麻为材料,研究了药材植物、粮蔬兼用植物和纤维类经济植物的净光合速率日变化情况及其对光合有效辐射响应的数学模型.结果表明:金银花、马铃薯和苎麻3种植物的净光合速率日变化曲线呈双峰型.且均为第1个峰持续时间较短、第2个峰持续时间很长,净光合速率日变化趋势第1个峰期间金银花与苎麻比较一致,而第2个峰期间马铃薯与苎麻比较一致;此外,3种植物的净光合速率对光合有效辐射的响应可用对数、线性、二项式等数学函数来描述,但以二项式描述更确切,依据各供试植物的二项式方程计算出光饱和点金银花为1 086.3 μmol/m2·s、马铃薯为1 160 μmol/m2·s、苎麻为1 141 μmol/m2·s.     

乌鸡黑色素对果蝇的紫外辐射保护作用

对黄体果蝇进行紫外辐射处理后,在含0.02或0.2mg/mL乌鸡黑色素的培养基中培养,通过测定果蝇寿命、繁殖力和SOD比活性来分析黑色素的紫外辐射保护作用。结果显示:果蝇在5min紫外辐射 0.2mg/mL黑色素组的下四分位(14.5±1.3)d、上四分位寿命(23.5±2.1)d以及平均寿命(15.7±7.1)d显著(P<0.05)高于5 min紫外辐射组(8.0±1.4)、(16.0±3.3)和(13.5±6.4)d。每对亲本果蝇在2min紫外辐射 0.2mg/mL黑色素组繁殖子代(50.0±11.4)只比2min紫外辐射组提高了156.4%(P<0.05)。另外,黑色素可能对辐射处理果蝇体内SOD比活性有保护作用,果蝇在5min紫外辐射 0.02mg/mL黑色素组和5min紫外辐射 0.2mg/mL黑色素组的SOD比活性((209.1±13.1)和(213.25±7.7)μmol/(mg.min))高于5min紫外辐射组((204.2±11.5)μmol/(mg.min)),但差异均不显著。本试验发现乌鸡黑色素能够延长辐射处理果蝇的寿命,提高繁殖力,对其SOD活性可能也具有保护作用。上述作用或许与黑色素清除自由基的特性有关,同时,2min紫外辐射 0.2mg/mL黑色素组高繁殖力的原因可能还与黑色素对果蝇生殖细胞的保护有关。     

Computed tomography diagnosis of eight dogs with brain infarction

Objective Medical records of eight dogs presenting with acute onset of neurological signs and a diagnosis of brain infarction as determined by computed tomography (CT) imaging were reviewed. Design Retrospective single-centre case review Results Ischaemic infarction in the territory of the rostral cerebellar artery was identified in three spaniel-breed dogs. All cerebellar infarcts were non-haemorrhagic. Telencephalic infarcts were identified in five dogs, in the territories of the middle cerebral artery (2/5) and rostral cerebral artery (3/5). One of these dogs had an ischaemic infarction, but all other infarctions appeared haemorrhagic. All dogs were geriatric (≥8 years old), with concurrent medical conditions identified in six dogs. One dog was euthanased after diagnosis because of the severity of its neurological signs and one dog was euthanased as a result of associated renal disease 2 months after diagnosis. Six dogs were alive at least 1 year after diagnosis. Conclusions CT is useful in the diagnosis of cerebrovascular accident in dogs, which can present as a spectrum of images with early changes in attenuation and subtle mass effects detected after infarction. CT is particularly sensitive for detecting haemorrhagic infarction, but under-represent ischaemic and lacunar infarctions when compared with MRI.     

Effects of ultraviolet-B radiation on immunity and carcass characteristics in quail

An experiment was conducted to evaluate the effects of UV-B radiation on immunity and carcass characteristics in quail. Three hundred Korean quail at 3 d old were weighed and randomly allocated into 5 groups (i.e., 30 males and 30 females per group), including 1 control group and 4 experiment groups (UV-1, UV-2, UV-3, and UV-4). Quail were subjected to UV-B irradiation with different doses: 0 µW/cm² (control), 1.4 µW/cm² (UV-1), 2.8 µW/cm² (UV-2), 5.6 (UV-3), and 8.4 µW/cm² (UV-4) each day. At 38 d of age, 15 males and 15 females in each group were randomly selected to measure immune index concentrations and carcass characteristics. The mean serum IgG, IgA, and alexin C₄ concentrations of UV-1 quail were significantly improved, whereas UV-3 and UV-4 quail had better live weight and carcass characteristics. Taking into account immunity and carcass characteristics together, we conclude that the optimum dose of UV radiation for Korean quail is 1.4 µW/cm² each day. Moreover, female quail had better carcass characteristics than males in most indices of carcass characteristics.     

基于一起雷击事故的加油站雷电防护探析

基于中国石油天然气股份有限公司广西桂林销售分公司灵川某加油站雷击事故的分析，对加油站外部和内部防雷设计进行了探讨，提出有效的雷电防护措施为加油站的综合防雷提供了参考。     

Observations on the oesophageal glands in some Tanzanian anurans

The occurrence and function of oesophageal glands In some anurans from Tanzania was investigated. The compound glands were present in the oesophageal submucosa of Ptychadena oxyrhynchus Smith, Ptychadena porosissima Steindachner, Phrynobatrachus acridoides Cope, Chiromantis xerampelina Peters, Leptopelis argenteus Pfeffer, Kassina maculata Dumeril, Afrixalus brachycnemis brachycnemis Boulenger, Hyperolius argus Peters, Hyperolius puncticulatus Pfeffer and Hyperolius tuberilinguis Smith, but were absent in Xenopus muelleri Peters, Bufo gutturalis Power and Phrynomerus bifasciatus bifasciatus Smith. It is suggested that in anurans, the oesophageal and gastric glands have similar functions.     

基于模拟光辐射和CO2浓度升高的山野豌豆光合特性研究

利用LI-6400便携式光合测定仪,对模拟光照强度和CO2浓度条件下山野豌豆(Vicia amoena Fisch.ex DC.)的光合作用及水分生理生态特性进行了研究.结果表明:山野豌豆的CO2饱和点为1017μmol/mol,光饱和点为800μtmol/m2·s,其水分利用效率(WUE)随模拟光辐射(SPR)增强略有升高,当SPR在100～2000μmol/m2·s内变化时,WUE维持在2.14～4.69mmol/mol之间,说明山野豌豆具有利用高浓度CO2的能力,受强光限制较小,为喜阳性植物.     

化工机械设备故障与事故管理的建议

化工行业作为国民经济中的重要行业,化工机械设备也是现代机械制造业不可或缺的重要部分,化工机械设备由于长时间的运作等影响因素发生了不同程度的故障,带来了较大的安全隐患。文章将从发生故障的类型、原因与管理措施三方面来探讨化工机械设备故障与事故管理,希望能为大家提供借鉴。     

浅析移动通信室内分布系统的豁免管理

通过理论计算,分析了移动通信室内分布系统是否符合国家电磁辐射豁免管理规定,并对中国移动浙江省内某地级分公司在某高层建筑内已安装并投入使用的移动通信室内分布系统进行了现状监测,根据监测结果,说明了符合国家电磁辐射豁免管理规定的移动通信室内分布系统,其在正常运行工况下所产生的电磁辐射水平必定符合国家要求。     

渔业船舶海上事故成因与对策分析

随着国家海洋战略的提出和海洋经济的发展,中国的渔业生产呈现出繁荣的景象,同时渔业船舶海上事故也常有发生,给渔民的人身和财产安全以及渔业生产的安全稳定带来了巨大的风险和隐患.基于此,通过运用事故致因理论,对不同类型渔业船舶事故发生影响因素进行分析,归纳渔业船舶海上事故的风险类型,参考系统安全理论,运用系统安全管理方法,结...