Transcontinental Tidal Gravity Profile across the United States

Data obtained from a transcontinental tidal gravity profile across the United States were analyzed. Results for the principal tidal constituents M(2) and O(1) have shed light on the long-standing problem of the indirect influence of ocean tides on the solid-earth tide. The profile consists of nine observational stations distributed almost evenly around latitudes 39 to 41 degrees north across the United States. The observed values of the gravimetric factor and the phase were found to depend on the tidal characteristics of the Atlantic and Pacific oceans. There is no observable correlation between tidal gravity parameters and the regional geology. When the influence of ocean tides is taken into account, it is possible for the first time to bring the gravimetric factors and phases for all the stations of a transcontinental network into a consistent system within the framework of the earth tidal theory.     

农民增收与城镇化发展的动态计量分析

在建立VAR模型的基础上,运用脉冲响应函数和预测方差分解来刻画城镇化发展与农民收入增长关系的相关性。结果表明,我国城镇发展与农民收入增长呈较强的正相关。因此,在当前条件下,加速推进城镇化发展是持续增加农民收入的重要途径。     

Control of alternative splicing by the differential binding of U1 small nuclear ribonucleoprotein particle.

Cellular factors controlling alternative splicing of precursor messenger RNA are largely unknown, even though this process plays a central role in specifying the diversity of proteins in the eukaryotic cell. For the identification of such factors, a segment of the rat preprotachykinin gene was used in which differential expression of neuropeptides gamma and K is dependent on alternative splicing of the fourth exon (E4). Sequence variants of the three-exon segment, (E3-E4-E5) were created, resulting in a sensitive assay for factors mediating the splicing switch between E4-skipping and E4-inclusion. A dinucleotide mutation in the 5' splice site of E4 that increase base-pairing of this site to U1 small nuclear RNA resulted in uniform selection of E4, whereas a control mutation that destroyed base-pairing resulted in uniform E4-skipping. Affinity selection of spliceosomes formed on these functionally distinct substrates revealed that the extreme difference in splicing was mediated by differential binding of the U1 small nuclear ribonucleoprotein particle (snRNP) to the 5' splice site of E4. These data show that, apart from its established role in selecting 5' splice sites, U1 snRNP plays a fundamental role in 3' exon selection and provides insight into possible mechanisms of alternative splicing.     

品牌危机管理机制——以乳制品行业为例

品牌形象一直企业最关心的问题,但是品牌危机问题日趋普遍。文章试图以乳制品行业为例,浅析品牌危机的管理机制。     

Phenolic antioxidants from the heartwood of Acacia confusa

In the present study, the ethanolic extracts from the heartwood of Acacia confusa, a species indigenous to Taiwan, exhibit strong antioxidant effects. Among all the fractions from ethanolic extracts of heartwood, the EtOAc soluble fraction exhibits the best antioxidant activity. The 80% 1,1-diphenyl-2-picrylhydrazyl radical inhibitory activity by the EtOAc extract was observed at a concentration of 5 mug/mL, and at the same dosage there was a similar free radical scavenging activity for (-)-ascorbic acid and (+)-catechin, both of which are well-known antioxidants. In addition, the EtOAc extract also protects PhiX174 supercoiled DNA against strand scission induced by hydroxyl radical. Furthermore, following by column chromatography and reverse-phase high-performance liquid chromatorgrapy, 10 pure phenolic compounds, including three major antioxidants (3,7,8,3',4'-pentahydroxyflavone, 7,8,3',4'-tetrahydroxy-3-methoxyflavone, and 3,4,2',3',4'-pentahydroxy-trans-chalcone) and a new flavonoid (3,7,8,3'-tetrahydroxy-4'-methoxyflavone), were isolated from the ethanolic extracts of A. confusa heartwood.     

Development of a molecular marker for a bruchid (Callosobruchus chinensis L.) resistance gene in mungbean

Bruchid, Callosobruchus spp. (Coleoptera: Bruchidae), is a serious pest during storage of seeds of mungbean (Vigna radiata (L.) Wilczek) and other Vigna species. A source of resistance to this pest has been identified in Vigna sublobata (Roxb.) Bairig. accession TC1966. Two hundred recombinant inbred lines at the F₁₂ generation have been developed for molecular mapping of bruchid resistance (Br) gene in TC1966. Through bulked segregant analysis (BSA), ten randomly amplified polymorphic DNA (RAPD) markers associated with the bruchid resistance gene were successfully identified. A total of four closely linked RAPDs were cloned and transformed into sequence characterized amplified region (SCAR) and cleaved amplified polymorphism (CAP) markers. Seven CAPs developed from the identified RAPD markers showed tighter linkage with the Br gene than the original RAPD. Through transformation of RAPDs into CAPs, codominant markers for bruchid resistance were successfully obtained. Homozygous genotypes of these PCR-based markers were estimated to contribute 85% of the variance for seed damage when the insect assay was performed under favorable growth conditions for bruchid.     

Bath immersion pharmacokinetics of florfenicol in Nile tilapia (Oreochromis niloticus)

Drug administration by immersion can be a preferable method in certain conditions especially for treating small-sized, anorexic, or valuable fish. Pharmacokinetic information regarding bath treatment is considerably lacking in comparison to other common administration routes. The current study aimed to investigate if immersion can be an effective route to administer florfenicol (FF) for treatment in Nile tilapia. Nile tilapia reared at 28°C were immersed with FF solution at concentrations of 50, 100, 200, 500, and 500/200 (3 hr/117 hr) ppm for 120 hr and moved to drug-free freshwater for another 24 hr. The serum FF concentration in 100, 200, and 500/200 ppm groups reached steady-state at 12 hr with concentrations of 2.44, 3.04, and 5.26 µg/ml, respectively, which were about 2% of the bathing concentrations. The target therapeutic levels of 1–4 µg/ml were attained and maintained within 1–12 hr, depending on the immersion concentration and the target MIC. Serum FF reached the target with shorter time at higher bathing concentration. Following the 120-hr bath, the serum FF declined with the first-order half-life of approximately 10 hr. A minimum of 100 ppm FF is required for treatment purpose, and an initial high loading concentration followed by maintenance concentration is a plausible way to reach in vivo therapeutic level in short time. Greater than 99% of the residual FF in the bathing water could be removed within 15 min by 0.05% NaOCl. Our results indicated that bath immersion is a promising potential route for FF administration in Nile tilapia.     

北京玉渊潭樱花景观评价模型构建

采用SBE法对北京玉渊潭公园的7类20个樱花植物景观群落进行评价,结合SD语义分析法分析影响樱花景观效果的主要因素,最终建立樱花景观预测模型。评价结果表明,层次感、色彩丰富度、光感、林下层统一度及乔木层枝叶整齐度5个指标是影响春季樱花景观质量的主要因素。玉渊潭中滨水樱花景观SBE均值最高,广场樱花景观均值最低;公园可营造更多滨水樱花景观,丰富岸线结构,调整植物群落的层次感及林下层的统一度和枝叶整齐度,并充分应用早春返青早的宿根花卉。