993 resultados para 312
Resumo:
Age and growth estimates for the blue shark (Prionace glauca) were derived from 411 vertebral centra and 43 tag-recaptured blue sharks collected in the North Atlantic, ranging in length from 49 to 312 cm fork length (FL). The vertebrae of two oxytetracycline-injected recaptured blue sharks support an annual spring deposition of growth bands in the vertebrae in sharks up to 192 cm FL. Males and females were aged to 16 and 15 years, respectively, and full maturity is attained by 5 years of age in both sexes. Both sexes grew similarly to age seven, when growth rates decreased in males and remained constant in females. Growth rates from tag-recaptured individuals agreed with those derived from vertebral annuli for smaller sharks but appeared overestimated for larger sharks. Von Bertalanffy growth parameters derived from vertebral length-at-age data are L∞ = 282 cm FL, K = 0.18, and t0 = –1.35 for males, and L∞ = 310 cm FL, K = 0.13, and t0 = −1.77 for females. The species grows faster and has a shorter life span than previously reported for these waters.
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本文综述了草原群落土壤呼吸研究的理论、方法、最新进展和主要成果。从2001年6月5日到10月15日,在内蒙古锡林河流域的一个典型草原群落放牧地段用气相色谱法对土壤呼吸进行了测定,并同期观测相应的环境因子,分析了它们之间的相互关系,并根据根系生物量和土壤呼吸的相关性外推出根系呼吸占土壤总呼吸的比例。同时,采用碱液吸收法对该草原群落和一个沼泽化草甸群落的土壤呼吸进行了比对测定,比较在不同生境下土壤呼吸速率的差异。另外,重点比较了两种常用的土壤呼吸测量方法——碱液吸收法和气相色谱法对典型草原群落土壤呼吸的测量效果。主要研究成果如下: 1.在草原群落,生物量(包括地上和地下生物量)、温度(包括气温和土壤温度)和水分及土壤呼吸的季节变化均呈不规则的波动曲线;土壤呼吸与土壤湿度高度相关,与温度尤其是土壤温度以及地下生物量之间存在着一定的相关性,但和地上生物量及绿色生物量之间几乎没有关系。 2.草原群落和草甸群落土壤呼吸的季节动态基本一致,均出现了两个峰值,分别出现在6月底和7月底,它们的变化范围分别为312.8~1738.9 mg C﹒m-2﹒d-1 和 354.6 ~2235.6 mg C﹒m-2﹒d-1,日平均土壤呼吸速率分别为785.9 mg C﹒m-2﹒d-1 和1349.6 mg C﹒m-2﹒d-1,草甸群落的土壤呼吸速率明显高于草原群落; 3.土壤水分是草原群落土壤呼吸的主要限制因子,但对草甸群落的土壤呼吸变化却基本没有影响;草甸群落中,地上总生物量与土壤呼吸速率间没有显著的相关关系,但地上部分绿色生物量与土壤呼吸间存在着显著的幂函数关系,而在草原群落中,土壤呼吸速率与地上活生物量或地上总生物量的相关关系均很弱。 4.在草原群落,根系呼吸占土壤总呼吸的比例为60.7% - 93.3%,平均为82%; 5.碱液吸收法和气相色谱法的测定结果具有很高的相关性(R2=0.7563),它们的季节动态基本一致,变化范围分别为从249.3~1795.1 mg C﹒m-2﹒d-1和从312.8~1738.9 mg C﹒m-2﹒d-1,平均值分别为634.2 mg C﹒m-2﹒d-1和802.7 mg C﹒m-2﹒d-1,碱液吸收法的测量值是气相色谱法的约1.4倍。
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The inability of emissions reduction methods to meet upcoming legislation without an unacceptable increase in vehicle cost is a major problem of automobile manufacturer. This work aims to develop a cost-effective reduction of automobile emissions. A prototype CO2 sensor with 5 msec response time was built and bench tested, then used on an engine. The sensor design was based on standard emissions measurement technology using non-dispersive IR absorption. An improved sensor has now been completed with significant improvements in terms of signal to noise ratio and long-term stability. The improved sensor will be used to measure CO2 concentrations on three different engines. The results will then be used to validate engine and catalyst models and to propose control strategies aimed at reducing overall emissions. A brief description of the sensor itself was presented. Original is an abstract.
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Amphioxus is a crucial organism for the study of vertebrate evolution. Although a genomic BAC library of Branchiostoma floridae has been constructed, we report here another BAC library construction of its distant relative species Branchiostoma belcheri. The amphioxus BAC library established in present study consists of 45,312 clones arrayed in one hundred and eighteen 384-well plates. The average insert fragment size was 120 kb estimated by Pulsed Field Gel Electrophoresis (PFGE) analysis of 318 randomly selected clones. The representation of the library is about 12 equivalent to the genome, allowing a 99.9995% probability of recovering any specific sequence of interest. We further screened the library with 4 single copied Amphi-Pax genes and identified total of 26 positive clones with average of 6.5 clones for each gene. The result indicates this library is well suited for many applications and should also serve as a useful complemental resource for the scientific community.
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本发明涉及一种无指盘臭蛙皮肤活性肽及及其基因和在制药中的应用,属于生物医学领域。无指盘臭蛙皮肤活性肽是无指盘臭蛙皮肤活性肽基因编码的一种单链多肽,分子量3015.63道尔顿,等电点10.3,多肽全序列一级结构为: Ala Thr Ala Leu Gly Leu Ser Ser Arg Gly Leu Leu Pro Ile Gly Phe Met Phe Lys Asp Thr Ile Arg Cys Arg Lys Tyr(ATALGLSSRGLLPIGFMFKDTIRCRKY)。编码无指盘臭蛙皮肤活性肽的基因由312个核苷酸组成,其中编码成熟无指盘臭蛙皮肤活性肽为第141-222位核苷酸。人工合成的无指盘臭蛙皮肤活性肽具有很强的抑制细菌和真菌生长的作用,可以作为制备病原微生物感染疾病的治疗药物被应用。无指盘臭蛙皮肤活性肽具有结构简单、人工合成方便、抗菌谱系广、抗菌活性强的特点。
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本发明涉及一种无指盘臭蛙臭蛙肽及其基因和在制药中的应用,属于生物医学领域。无指盘臭蛙臭蛙肽是无指盘臭蛙臭蛙肽基因编码的一种单链多肽,分子量1814.11道尔顿,等电点8.08,多肽全序列一级结构为: Gly Cys Ser Arg Trp Ile Ile Gly Ile His Gly Gln Ile Cys Arg Asp。(GCSRWIIGIHGQICRD)。编码无指盘臭蛙臭蛙肽的基因由312个核苷酸组成,其中编码成熟无指盘臭蛙臭蛙肽为第141-189位核苷酸。人工合成的无指盘臭蛙臭蛙肽具有很强的抑制细菌和真菌生长的作用,可以作为制备病原微生物感染疾病的治疗药物被应用。本发明的无指盘臭蛙臭蛙肽具有结构简单、人工合成方便、抗菌谱系广、抗菌活性强的特点。
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利用地高辛标记技术,对从双峰驼肝脏和肾脏提纯的线粒体DNA进行了标记,制成探针,并用它检测了包含于白细胞总DNA中的微量线粒体DNA。结果表明这一技术完全可以成功地用于微量线粒体DNARFLP的分析。
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Phylogenetic relationships among representative species of the family Rhacophoridae were investigated based on 2904 bp of sequences from both mitochondrial (12S rRNA, 16S rRNA, the complete t-RNA for valine), and nuclear (tyrosinase, rhodopsin) genes. Max
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BACKGROUND: Neurotrophin-4 (NT-4) can promote neuronal growth, development, differentiation, maturation, and survival. NT-4 can also improve recovery and regeneration of injured neurons, but cannot pass through the blood-brain barrier, which limits its ac