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1.
湖南土家族的体质特征   总被引:20,自引:8,他引:12  
以20至69岁的湖南土家族人为观察测量对象,根据1392人(男896,女496)的身高,1038人(男668,女370)的头部测量,364人(男235,女129)的五官测量和观察结果,分析该民族的体质特征,并与国内其他民族相比较。  相似文献   

2.
维吾尔族的体质特征研究   总被引:37,自引:12,他引:25  
艾琼华  肖辉 《人类学学报》1993,12(4):357-365
1991年5月,对新疆伊梨维吾尔族529人(男271,女258)进行了活体观察和测量。观察29项,测量92项。维吾尔族的主要特征是:黑直发,黑褐色眼,眉毛较浓密,大都有上眼脸皱褶,鼻根中等偏高,大多为直形鼻,鼻尖向前,鼻基部下垂,大多有达尔文结节,耳垢湿型。头面部指数分型,属于特短头型,阔头型和高头型。身材中等偏高,平均身高男168.6毫米,女1578.8毫米。  相似文献   

3.
应用模拟试验的方法,研究了“草基-鱼塘”系统中的能量转化与养分循环.结果表明,该系统中饲草对太阳能的利用率为0.83%,鱼对饲料能的转化率为7.3%.与以粮食作为鱼饲料比较,单位面积草地的产鱼当量是粮食作物的1.6倍.鱼对饲料N、P、K的转化率分别为16.8%、32.3%和2.0%.塘泥沉积的N、P分别占饲料的23.4%和56.1%;猪对饲料N、P、K的转化率分别为20.5%、33.7%和4.6%,猪粪尿回收饲料N为36.4%、P为63.8%、K为39.4%.猪-草-鱼结合的基塘系统其能量和养分转化效率均高于单一的养鱼系统.  相似文献   

4.
We report for the first time the application of a biochip using the molecular beacon (MB) detection scheme. The usability of this biochip novel detection system for the analysis of the breast cancer gene BRCA1 is demonstrated using molecular beacon probes. The MB is designed for the BRCA1 gene and a miniature biochip system is used for detection. The performance of the biochip-MB detection system is evaluated. The optimum conditions for the MB system for highest fluorescence detection sensitivity are investigated for the detection system. The detection of BRCA1 gene is successfully demonstrated in solution and the limit of detection (LOD) is estimated as 70 nM.  相似文献   

5.
A surgical operating apparatus for fish that is effective for cranial surgery is described. The fishes are secured with clamp-arms which extend against the pectoral and pelvic girdles. The head is held by a plexiglass mouthpiece, designed specifically for the fish species under investigation. The mouthpiece is also responsible for gill irrigation. The use of the apparatus for the surgical pinealectomy of salmonids is described.  相似文献   

6.
草基—鱼塘生态系统的能量转化与养分循环研究   总被引:7,自引:2,他引:5  
应用模拟试验的方法,研究了“草基-鱼塘”系统中的能量转化与养分循环.结果 表明,该系统中饲草对太阳能的利用率为 0. 83%,鱼对饲料能的转化率为 7. 3%.与以粮 食作为鱼饲料比较,单位面积草地的产鱼当量是粮食作物的1.6倍.鱼对饲料N、P、K的 转化率分别为16.8%、32.3%和2.0%.塘泥沉积的N、P分别占饲料的23.4%和56.1%; 猪对饲料 N、 P、 K的转化率分别为 20. 5%、 33. 7%和 4. 6%,猪粪尿回收饲料 N为 36. 4%、 P为 63. 8%、 K为 39. 4%.猪-草-鱼结合的基塘系统其能量和养分转化效率均高于单一的 养鱼系统.  相似文献   

7.
8.
A method for the determination of a synthetic polymeric compound with antitumor activity (copovithane) and methylamine in blood plasma and urine is described. Copovithane is prepared by radical polymerisation of a diurethane with N-vinylpyrrolidone.The method is based on high-performance liquid chromatography of the methylamine hydrochloride which arises during the hydrochloric acid hydrolysis of the parent substance. The methylamine hydrochloride is converted to the trinitrobenzenesulphonyl derivative for the purpose of chromatographic detection.The limit of determination for copovithane in blood plasma is 1.2 mg/l and in urine 1.5 mg/day. The determination limit for methylamine in blood plasma is 0.2 mg/1 and in urine 0.3 mg/day. The imprecision is dependent on the sample, and amounts to ± 6.8% for blood plasma and ± 6.4% for urine.  相似文献   

9.
A steady-state nonlinear feedforward controller (FFC) for measurable disturbances is designed for a continuous bioreactor, which is represented by Hammerstein type nonlinear model wherein the nonlinearity is a polynomial with input multiplicities. The manipulated variable is the feed substrate concentration (Sf) and the disturbance variable is the dilution rate (D). The productivity (Q=DP) is considered as the controlled variable. The desired value of Q=3.73 gives two values of feed substrate concentration. The nonlinearity in the gain is considered for relating output to the manipulated variable and separately for the relation between output to disturbance variable. The FFC is also designed for the overall linearized system. The performance of the FFC is evaluated on the nonlinear differential equation model. The FFC is also designed for the model based on a single nonlinear steady-state equation containing both D and Sf. This nonlinear FFC gives the best performance. The nonlinear FFC is also designed by using only linear gain for the disturbance and nonlinear gain for the manipulated variable. Similarly, nonlinear FFC is also designed by using linear gain for the manipulated variable and the nonlinear gain for the disturbance variable. The performances of these FFC schemes are compared.  相似文献   

10.
1. The rate constants for NADH binding and dissociation for carboxymethylated alcohol dehydrogenase have been determined and compared to those for the native enzyme. 2. Steady-state and transient kinetic experiments have shown that the hydrogen transfer step is rate-determining for oxidation of ethanol by carboxymethylated alcohol dehydrogenase. The rate constant of 0.19 s-1 is considerably slower than that for the native enzyme. 3. The steady-state parameter, V/[E], was obtained for each of a series of alcohols and correlated with the Taft sigma parameter. The linear relationship obtained indicates that the same step, hydrogen transfer, is rate-determining for all the alcohols. The sigma value obtained is the same as for the native enzyme; the implications of this for the mechanism of hydrogen transfer are discussed.  相似文献   

11.
The P1 ParA protein is an ATPase that recognizes the parA promoter region where it acts to autoregulate the P1 parA–parB operon. The ParB protein is essential for plasmid partition and recognizes the cis -acting partition site parS . The regulatory role of ParA is also essential because a controlled level of ParB protein is critical for partition. However, we show that this regulatory activity is not the only role for ParA in partition. Efficient partition can be achieved without autoregulation as long as Par protein levels are kept within a range of low values. The properties of ParA mutants in these conditions showed that ParA is essential for some critical step in the partition process that is independent of par operon regulation. The putative nucleotide-binding site for the ParA ATPase was identified and disrupted by mutation. The resulting mutant was substantially defective for autoregulation and completely inactive for partition in a system in which the need for autoregulation is abolished. Thus, the ParA nucleotide-binding site appears to be necessary both for the repressor activity of ParA and for some essential step in the partition process itself. We propose that the nucleotide-bound form of the enzyme adopts a configuration that favours binding to the operator, but that the ATPase activity of ParA is required for some energetic step in partition of the plasmid copies to daughter cells.  相似文献   

12.
军标菌株生活史中各阶段生长发育时间的研究   总被引:3,自引:0,他引:3  
为了更好地研究军标菌在其应用中的实验周期问题 ,采用插片培养法和载片培养法对军标中 5株实验菌的生活史中各阶段生长发育所需时间进行了研究。结果表明 ,5株菌的各时期生长发育所需时间有所不同。整个生活史最长的 4940min ,如AS 3 .42 5 4。最短的 3 888min ,如AS 3 .3 95 0。孢子萌发阶段所需时间也各不相同 ,最长的需 1 5 2 0min ,如AS 3 .3 885。最短的需 640min ,如AS 3 .3 95 0。这一研究为军标中霉菌试验周期 ,即 2 8d过长而且完全可缩短试验周期的观点 ,提供了有力的证据。  相似文献   

13.
The assumption that the poor constitute a subsociety with a homogeneous subculture is examined empirically in an urban poverty sample. The existence of subcultural differences in the sample was tested by using a number of criteria that have been suggested for classifying cultural systems. The data indicate that for the sample studied there are two subcultures–one Black and one White. A hypothesis for the development and persistence of subcultural variations is proposed. The research which is reported and that which is suggested is seen as a necessity for providing an objective basis for the structuring of domestic social change programs.  相似文献   

14.
Phanerochaete chrysosporium produces intracellular soluble and particulate beta-glucosidases and an extracellular beta-glucosidase. The extracellular enzyme is induced by cellulose but repressed in the presence of glucose. The molecular weight of this enzyme is 90,000. The K(m) for p-nitrophenyl-beta-glucoside is 1.6 x 10 M; the K(i) for glucose, a competitive inhibitor, is 5.0 x 10 M. The K(m) for cellobiose is 5.3 x 10 M. The intracellular soluble enzyme is induced by cellobiose; this induction is prevented by cycloheximide. The presence of 300 mM glucose in the medium, however, had no effect on induction. The K(m) for p-nitrophenyl-beta-glucoside is 1.1 x 10 M. The molecular weight of this enzyme is approximately 410,000. Both enzymes have an optimal temperature of 45 degrees C and an E(act) of 9.15 kcal (ca. 3.83 x 10 J). The pH optima, however, were approximately 7.0 and 5.5 for the intracellular and extracellular enzymes, respectively.  相似文献   

15.
于玉米成熟期选择健壮茎秆的基部第三节间为材料,采用徒手切片法、冰冻切片法、石蜡切片法、薄切片法等4种方法,比较不同方法的玉米茎秆组织结构切片质量,为研究玉米茎秆结构与其倒伏的关系奠定技术基础。结果表明:徒手切片法是获得成熟玉米秆组织结构切片较为方便、快速的方法,切片面积较大,适合大范围观察统计;冰冻切片法是获得成熟玉米秆组织结构较快的方法,切片面积较小,适合小范围观察;薄切片是获得高质量成熟玉米秆组织结构切片的最好方法,但切片面积太小,适合高倍数显微观察和小范围电镜扫描观察组织结构;石蜡切片不适合作为成熟玉米秆的组织切片方法。研究认为,徒手切片法是最适合成熟玉米秆组织结构观察研究的制片方法。  相似文献   

16.
SYNOPSIS. Uniform names for the stages, processes and structures of apicomplexan protozoa are proposed and defined, and names that should be superseded are listed. The same names are used for the same stages of all members of the group. Gregarines are designated as either septate or aseptate rather than as polycystid or monocystid. The gregarine stage often called a sporadin is recognized for what it is, a gamont. The cyst formed around 2 gregarine gamonts in which zygotes are formed is a gametocyst; it contains oocysts which in turn contain sporozoites. The term “spore” is inappropriate for these oocysts. The apical complex includes the polar ring, conoid, rhoptries, micronemes and subpellicular tubules. The gregarine “pseudocyst” is actually a gametocyst residuum. The term micropore is preferred to cytostome for the apicomplexan structure, since it is visible only with the electron microscope.  相似文献   

17.
用运动文字的阅读眼动实验来研究运动图像识别与眼动控制的关系,并与一般OKN眼动及一般正常阅读进行对比,探讨了速度及位置信息处理与内容信息处理的关系.实验结果表明;(1)一般正常文字阅读的眼动是Saccades眼动与注视停顿;运动文字识别阅读的眼动中没有注视停顿,而是快、慢交替的OKN眼动,在其慢相期间即运动文字与视网膜相对静止期间采集内容信息进行处理,慢相期间既处理文字内容信息又处理运动速度信息,说明对运动速度与内容信息的处理是并行的.(2)在运动文字运动速度高达80°/s以上时,已不能阅读甚至不能识别单字意义,但仍可产生OKN眼动;这一方面证实阅读速度的受限不在于眼球运动的跟踪能力,而在于高级识别中枢的解码速度,另一方面也说明OKN眼动不是在识别后才产生,而是进行运动图象识别的必要条件.(3)运动文字识别阅读的速度不低于一般正常文字阅读的速度.本文的结果还证实OKN眼动的快相眼动有别于Foveating Saccades.  相似文献   

18.
The kinetics of the NADP+- and phosphate-dependent oxidation of glutamic acid 5-semialdehyde are consistent with a rapid-equilibrium random order mechanism. The Km for DL-pyrroline-5-carboxylic acid is 2.5 mM, for NADP+ is 0.05 mM and for phosphate is 0.35 mM. The Vmax is approx. 8.0 units per mg protein. The reaction is highly specific for the DL-pyrroline-5-carboxylic acid and NADP+, but a number of divalent anions can substitute for phosphate. NADPH is competitive with respect to all three substrates and an analog of gamma-glutamyl phosphate, 3-(phosphonoacetylamido)-L-alanine, is competitive with respect to DL-pyrroline-5-carboxylic acid and non-competitive with respect to NADP+ and phosphate, suggesting dead-end complex formation.  相似文献   

19.
We have developed a cell-based 96-well microtiter plate, high throughput assay for measuring both type I and type II interferon (IFN) activity on human cells. This assay makes use of a previously described IFN-specific reporter stably expressed in human HT 1080 cells. The induction of the reporter by IFN is determined by measuring the IFN-dependent expression of CD2 on the cell surface. The cytokine-induced expression of CD2 occurs within 48 h and is measured using a time-resolved fluorometric immunoassay. The limit of detection for type I IFN is.0.4 IU/ml. Interassay and intraassay coefficients of variation were 1.1% and 1.3% for the medium control (31 IU IFNb1b/ml), respectively. The limit of detection for type II IFN is.8 IU/ml, and the assay coefficients of variation are similar to those determined for type I IFNs. The level of sensitivity for this assay is comparable to other assays commonly used to measure IFN activity on cells. The current assay has an advantage over antiviral and antiproliferative assays, in that there is no requirement for the use of pathogenic virus or for determining viable cell numbers. The current assay is ideally suited for increasing sample screening and high-capacity automation, making it an excellent tool for drug discovery.  相似文献   

20.
General expressions for mass, elemental, energy, and entropy balances are derived and applied to microbial growth and product formation. The state of the art of the application of elemental balances to aerobic and heterotrophic growth is reviewed and extended somewhat to include the majority of the cases commonly encountered in biotechnology. The degree of reduction concept is extended to include nitrogen sources other than ammonia. The relationship between a number of accepted measures for the comparison of substrate yields is investigated. The theory is illustrated using a generalized correlation for oxygen yield data. The stoichiometry of anaerobic product formation is briefly treated, a limit to the maximum carbon conservation in product is derived, using the concept of elemental balance. In the treatment of growth energetics the correct statement of the second law of thermodynamics for growing organisms is emphasized. For aerobic heterotrophic growth the concept of thermodynamic efficiency is used to formulate a limit the substrate yield can never surpass. It is combined with a limit due to the fact that the maximum carbon conservation in biomass can obviously never surpass unity. It is shown that growth on substrates of a low degree of reduction is energy limited, for substrates of a high degree of reduction carbon limitation takes over. Based on a literature review concerning yield data some semiempirical notions useful for a preliminary evolution of aerobic heterotrophic growth are developed. The thermodynamic efficiency definition is completed by two other efficiency measures, which allow derivation of simple equations for oxygen consumption and heat production. The range of validity of the constancy of the rate of heat production to the rate of oxygen consumption is analyzed using these efficiency measures. The energetic of anaerobic growth are treated—it is shown that an approximate analysis in terms of an enthalpy balance is not valid for this case, the evaluation of the efficiency of growth has to be based on Gibbs free energy changes. A preliminary analysis shows the existence of regularities concerning the free energy conservation on anaerobic growth. The treatment is extended to include the effect of growth rate by the introduction of a linear relationship for substrate consumption. Aerobic and anaerobic growth are discussed using this relationship. A correlation useful in judging the potentialities for improvement in anaerobic product formation processes is derived. Finally the relevance of macroscopic principles to the modeling of bioengineering systems is discussed.  相似文献   

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