Limiting States Of Internal Wave Rays

Existing models of baroclinic tides are based upon the "traditional approximation'', i. e., neglect of the horizontal component of the Earth's rotation, leading to a well- known conclusion that no freely propagating internal waves can exist beyond the critical latitude and the wave rays are symmetric to the vertical. However, recent studies have contended that the situation may change if both the vertical and horizontal components of the Earth's rotation are taken into account. With the full account of the Coriolis force, characteristics of the internal wavefield generated by tidal flow over uneven topography are investigated. It is found that "nontraditional effects'' profoundly change not only the dynamics of internal waves but also the rate at which the barotropic tidal energy is fed into the internal wavefield. Discarding the traditional approximation, internal waves are proved to be able to generate poleward of the critical latitude, rays of which are no longer symmetric and the limiting values of ray angles become greater or less than 90 degrees, depending on the local latitude and the direction of ray. More importantly, in contrast to the predictions of models based upon the traditional approximation, a substantial conversion occurs in the situations when stratification is so weak that the buoyancy frequency is below the tidal one.

双光栅并联匹配解调技术的工程化研究

在分析和综合其他数据处理方案优缺点的基础上,提出了一种基于分区查表法的有效数据处理方案.该方案先确定待处理的电压商值在三段近似线性曲线上所属区域,再执行查表法将其和微应变量一一对应.这种处理方案不但解决了传统单匹配解调技术中的双值和可测试范围小的问题,而且提高了测试准确度.根据实验结果,采用普通的光纤光栅对,系统可传感的应变范围可达525 με,准确度可达±1 με.

The Anti-HIV Actions of 7-and 10-Substituted Camptothecins

Camptothecin (CPT), a traditional anti-tumor drug, has been shown to possess anti-HIV-1 activity. To increase the antiviral potency, the anti-HIV activities of two CPT derivatives, 10-hydroxy-CPT and 7-hydroxymethyl-CPT, were evaluated in vitro. The therapy index (TI) of CPT, 10-hydroxy-CPT and 7-hydroxymethyl-CPT against HIV-1(IIIB) in C8166 were 24.2, 4.2 and 198.1, and against clinical isolated strain HIV-1(KM018) in PBMC were 10.3, 3.5 and 66.0, respectively. While the TI of CPT, 10-hydroxy-CPT and 7-hydroxymethyl-CPT against HIV-2(CBL-20) were 34.5, 10.7 and 317.0, respectively, and the TI of the three compounds against HIV-2(ROD) showed the similar values. However, when the antiviral mechanisms were considered, we found there was no inhibition of 7-hydroxymethyl-CPT on viral cell-to-cell transmission, and was no inhibition on reverse transcriptase, protease or integrase in cell-free systems. 7-Hydroxymethyl-CPT showed no selective killing of chronically infected cells after 3 days of incubation. In conclusion, 7-hydroxymethyl-CPT showed more potent anti-HIV activity, while 10-hydroxy-CPT had less efficient activity, compared with the parent CPT. Though the antiviral mechanisms remain to be further elucidated; the modification of -OH residues at C-7 of CPT could enhance the antiviral activity, while of -OH residues at C-10 of CPT had decreased the antiviral activity, which provides the preliminary modification strategy for anti-viral activities enhancement of this compound.

C-values of seven marine mammal species determined by flow cytometry

C-values, which estimate genome size, have puzzled geneticists for years because they bear no relationship to organismal complexity. Though C-values have been estimated for thousands of species, considerably more data are required in order to better understanding genome evolution. This is particularly true for mammals, in which C-values are known for less than 8% of the total number of mammalian species. Among marine mammals, a C-value has been estimated only for the bottlenose dolphin (Tursiops truncatus). Thus examination of additional species of marine mammals is necessary for comparative purposes. It will enable a better understanding of marine mammal genome evolution, and it is also relevant to conservation, because larger genome size has been linked to increased likelihood of extinction in some plant and animal groups. Our study presents C-values of seven marine mammal species, including five cetacean species that are endangered to varying degrees. Similarly to the results for other groups, our results suggest that larger genome size in cetaceans is related to an increased likelihood of extinction.

Empirical modelling of submersed macrophytes in Yangtze lakes

Submersed macrophytes in Yangtze lakes have experienced large-scale declines due to the increasing human activities during past decades. To seek the key factor that affects their growth, monthly investigations of submersed macrophytes were conducted in 20 regions of four Yangtze lakes during December, 2001-March, 2003. Analyses based on annual values show that the ratio of Secchi depth to mean depth is the key factor (50% of macrophyte biomass variability among these lakes is statistically explained). Further analyses also demonstrate that the months from March to June are not only the actively growing season for most macrophytes, but the key time the factor acts. Five key-time models yielding higher predictive power (r(2) reaches 0.75,0.76,0.77,0.69 and 0.81) are generated. A comparison between key-time models and traditional synchronic ones indicates that key-time models have higher predictive power. Analyses of transparency thresholds during macrophyte growing season and the limitations of the models are presented. The models and other results may benefit the work concerning submersed macrophyte recovery in Yangtze lakes. (c) 2005 Elsevier B.V. All rights reserved.

Phylogenetic relationships among Trichodinidae (Ciliophora : Peritricha) derived from the characteristic values of denticles

The phylogenetic relationships among trichodinids remain obscure. As an important diagnostic marker, the morphology of the denticles in the adhesive disc as well as the adoral spiral has been widely used in generic discrimination and species identification of trichodinids. We studied the characters of denticles of the ten genera of Trichodinidae and the sole genus Urceolaria of Urceolariidae by using a quantitative method. The characteristic values were used to generate Manhattan distance, on which the dendrogram was based to construct with the Unweighted Paired Group Method using the Arithmetic mean (UPGMA). The investigations show that all the genera of the family Trichodinidae were clearly separate from the outgroup Urceolaria, and within the Trichodinidae: (i) Dipartiella grouped with Trichodinella and Tripartiella and lay in the closest position to the outgroup with a low dissimilarity, suggesting Dipartiella might be the most primitive genus in the family; (ii) Hemitrichodina clustered in a single clad and lay in the farthest position to the outgroup with the highest dissimilarity, indicating that it might be the most advanced genus; and (iii) the other 6 genera, Trichodina, Paratrichodina, Semitrichodina, Vauchomia, Pallitrichodina and Trichodoxa clustered in a big clad with very low dissimilarity, showing that they are closely related to each other. We discuss the evolutionary trend of the denticle and conclude that the denticles of the adhesive disc should be an apomorphic feature of the trichodinids and their changes could reflect the evolutionary tendencies of these ciliates.

The multi-weight neuron with geometry algorithm and its application

A novel approach for multi-dimension signals processing, that is multi-weight neural network based on high dimensional geometry theory, is proposed. With this theory, the geometry algorithm for building the multi-weight neuron is mentioned. To illustrate the advantage of the novel approach, a Chinese speech emotion recognition experiment has been done. From this experiment, the human emotions are classified into 6 archetypal classes: fear, anger, happiness, sadness, surprise and disgust. And the amplitude, pitch frequency and formant are used as the feature parameters for speech emotion recognition. Compared with traditional GSVM model, the new method has its superiority. It is noted that this method has significant values for researches and applications henceforth.

Mandarin speech emotion recognition based on high dimensional geometry theory

In this paper, a novel approach for mandarin speech emotion recognition, that is mandarin speech emotion recognition based on high dimensional geometry theory, is proposed. The human emotions are classified into 6 archetypal classes: fear, anger, happiness, sadness, surprise and disgust. According to the characteristics of these emotional speech signals, the amplitude, pitch frequency and formant are used as the feature parameters for speech emotion recognition. The new method called high dimensional geometry theory is applied for recognition. Compared with traditional GSVM model, the new method has some advantages. It is noted that this method has significant values for researches and applications henceforth.

Determination of the values of hole-mixing coefficients due to interface and electric field in GaAs/AlxGa1-xAs superlattices

Numerical calculations within the envelope function framework have been performed to analyze the relations between the magnitude of in-plane optical anisotropy and the values of the additional hole-mixing coefficients due to interface and electric field in (001) symmetric GaAs/AlxGa1-xAs superlattices for light propagating along the [001] direction. It is found that the heavy- and light-hole states are mixed independently by interface and electric field. The numeric results demonstrate that the line shape of the in-plane anisotropic spectrum is determined by the ratio of the two hole-mixing coefficients. Theoretical analysis shows that with the help of simple calculation of the anisotropy at k=0, reliable values of the hole-mixing coefficients can be determined by reflectance-difference spectroscopy (IDS) technique, demanding no tedious fitting of experimental curves. The in-plane optical anisotropy measured by RDS provides a new method of getting the information on buried interfaces through the Value of the hole-mixing coefficient due to interface.