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Background: Previous studies have reported inconsistent results regarding blastocyst selection with high cell number of day 3 (D3) and the eventual pregnancy outcomes. Thus, this study investigated the relationship between the D3 cell number and clinical outcomes of single blastocyst transfer (SBT) in vitrified-warmed transfer cycles. Methods: A total of 1144 vitrified-warmed cycles of SBT were retrospectively analyzed. Based on the D3 cell number, the cycles were divided into four groups: group A (3–7 cells, n = 130); group B (8–9 cells, n = 621); group C (10–12 cells, n = 328); and group D (13–16 cells, n = 65). The differences in live birth rate (LBR), clinicalpregnancy rate, and miscarriage rate were examined among the four groups. Results: The LBR and clinical pregnancy rate increased with the D3 cell number (P < 0.01). No significant difference was found in the miscarriage rate among the groups (P= 0.055). After adjusting for confounding factors, the LBR was significantly higher in groups C (odds ratio [OR] = 1.506, 95% confidence interval [CI]: 1.148–1.976, P < 0.01) and D (OR = 2.081, 95% CI: 1.218–3.556, P< 0.01) than in group B. Conclusions: A high D3 cell number (>9 cells) was associated with a high LBR in the vitrified-warmed SBT cycle. The cell number of D3 embryos can be an important reference indicator for blastocyst selection. Among blastocysts with the same morphological score, those with >9 cells on D3 can be preferentially selected for transplantation.

Both the river network and the regions outside the estuary mouths in the Pearl River Delta (PRD) of China experienced significant changes from 1999 to 2014. A validated hydrodynamic model across the entire PRD and adjacent regions outside the estuary mouths is employed to simulate both present (circa 2014) and past conditions (circa 1999). The total net water flux of the PRD decreased. The flow division of the West River is increasing, with values of 3.63% and 4.66% for the Makou and Denglongshan sections, respectively. The flood flow division of the North River is correspondingly decreasing. The value of the flood levels significantly decreased (more than 2 m) in the upper portion of the PRD, moderately decreased in the middle of the PRD (more than 1.1 m) and slightly decreased in the bottom part of the PRD (less than 0.22 m). In addition, the effects of morphodynamic evolution in different regions (i.e., the river network, coastline and bathymetry changes outside the estuary mouth) on floods are quantified. The results indicate that the decreased net water flux was caused by the increased channel’s capacity and the gentler water-level profile from the downcutting riverbed of the river network. The uneven morphodynamic evolution of the riverbed of the river network was primarily responsible for changes in the flood flow division in the PRD, and morphological evolution outside the estuary mouth was primarily responsible for reallocation within the outlets. The downcutting riverbed in the river network was primarily responsible for the lower flood levels in the upper and middle portion of the PRD. Reclamation seemed to have barely affected the flood level. The deepening bathymetry outside the estuary mouth was mainly responsible for the decrease in the flood level in the bottom portion of the PRD. The downcutting riverbed may decrease the stability of the riverbank, increasing the flood risk. The morphodynamic evolution of both the river network and the regions outside the estuary mouth should be considered to avoid unwanted side effects when designing local projects and flood mitigation strategies for the PRD.

Accurate salinity prediction can support the decision-making of water resources management to mitigate the threat of insufficient freshwater supply in densely populated estuaries. Statistical methods are low-cost and less time-consuming compared with numerical models and physical models for predicting estuarine salinity variations. This study proposes an alternative statistical model that can more accurately predict the salinity series in estuaries. The model incorporates an autoregressive model to characterize the memory effect of salinity and includes the changes in salinity driven by river discharge and tides. Furthermore, the Gamma distribution function was introduced to correct the hysteresis effects of river discharge, tides and salinity. Based on fixed corrections of long-term effects, dynamic corrections of short-term effects were added to weaken the hysteresis effects. Real-world model application to the Pearl River Estuary obtained satisfactory agreement between predicted and measured salinity peaks, indicating the accuracy of salinity forecasting. Cross-validation and weekly salinity prediction under small, medium and large river discharges were also conducted to further test the reliability of the model. The statistical model provides a good reference for predicting salinity variations in estuaries.

This paper proposes a new high-resolution finite volume method for solving the two-dimensional (2D) solute transport equation using an unstructured mesh. A new simple r-factor algorithm is introduced into the Total Variation Diminishing flux limiter to achieve a more efficient yet accurate high-resolution scheme for solving the advection term. To avoid the physically-meaningless negative solutions resulted from using the Green–Gauss theorem, a nonlinear two-point flux approximation scheme is adopted to deal with the anisotropic diffusion term. The developed method can be readily coupled with a two-dimensional finite-volume-based flow models under unstructured triangular mesh. By integrating with the ELCIRC flow model, the proposed method was verified using three idealized benchmark cases (i.e., advection of a circle-shaped solute field, advection in a cyclogenesis flow field and transport of a initially square-shaped solute plume), and further applied to simulate the non-reactive solute transport process driven by irregular tides in the Deep Bay, eastern Pearl River Estuary of China. These cases are also simulated by models using other existing methods, including different r-factor for advection term and the Green–Gauss theorem for diffusion term. The comparison between the results from the new method and those from other existing methods demonstrated the new method could describe advection induced concentration shock and discontinuities, and anisotropic diffusion at high resolution without providing spurious oscillations and negative values.

The nacre color of the pearl mussels is one of the most important traits for the pearl industry. In this study, to evaluate the effectiveness of the nacre color selection of the freshwater pearl mussel Hyriopsis cumingii, the characteristics of nacre color from a purple, white, and a commercial farmed strain were detected, respectively, by measuring the color parameters of CIEL*a*b* (CIELAB) system. The analysis of the variation among the color parameters showed that the uniformity of the nacre color in purple or white strain had been significantly improved over that of the farmed strain. The principal component analysis indicated that the first principal component (PC1) was most affected by color parameter a* where a positive value indicates a hue of red and a negative value indicates a green in the CIELAB color space. The second principal component (PC2) was most affected by color parameter b* where a positive value indicates a hue of yellow and a negative value indicates blue. The contribution...

River mouth bars commonly exist in estuaries and are important for flood control, estuarine ecology, and the navigation of estuarine areas. The Modaomen Estuary is a river-dominated estuary in the Pearl River Delta and has a typical river mouth bar. Here, hydrologic and bathymetric datasets that span 2000–2011 are used to analyze the relationship between the fluvial input of river discharge and sediment load and the evolution of the river mouth bar. The results show that the eastern and western channels have notably extended seaward since 2000. The evolution rates exhibit distinct asymmetry, with the seaward extension rate of the eastern channel being approximately 1.6 times greater than that of the western channel. The upstream bar face and bar back of the center mouth bar have been eroded, and intensive human activities have significantly affected the evolution of the center mouth bar. The center mouth bar’s apex has consistently moved seaward from 2000 to 2011. River discharge (especially during extreme river floods), rather than sediment load, has played a more vital role in the development of the bifurcation channels and the center mouth bar. An empirical relationship between the bar-apex displacement rates and dominant discharge is obtained based on the observations, indicating that greater river discharge and longer duration will move the bar apex further seaward. The bar apex’s displacement during the extreme river floods of “2005.6” and “2008.6” was 133.6 m and 99.4 m, respectively.

The coastal area is the area where human activities are most frequent. Coastal waters provide rich resources for the development of human society. The current in coastal waters is affected by shoreline, buildings in water and tidal current. The scientific location of buildings in water is of great scientific and practical significance for the sustainable development and utilization of coastal zones. In this paper, the Jiu’ao Bay is taken as the object, and mathematical and physical models are used to simulate the influence of hydrodynamic force and water exchange capacity caused by different locations of intake. The simulation results show that after the construction of the water intake, the water flow is squeezed by the water intake, and the water flow is forced to deflect eastward, while the west side water flow is deflected to the south. The flow diversion of the rising tide is advanced, and the flow convergence of the falling tide is delayed. As a result, the water exchange capacity in Jiu’ao Bay is reduced. Compared with Scheme 1, the location of Scheme 2 is less hydrodynamic, so the impact is less.

Color is an important indicator in evaluating the quality of pearls. Despite the well-developed technology of pearl production, evidence for what determines pearl color is largely absent. In the present study, a 2 × 2 complete double-row implantation experiment was conducted using the purple and white strains of mussels of Hyriopsis cumingii in three different aquaculture environments. The effect of purple and white strains of mussels on seedless pearl color was analyzed using a mixed linear model. The results showed that the effect of the donor mussel, which provides the mantle tissues, on seedless pearl color was significant (P < 0.001), whereas neither the strain of the host mussel nor the aquaculture environment had a significant influence on pearl color. The estimated values for the effect of the donor mussel on pearl color parameters CIE L*, a*, and b* were –9.35, 2.49, and 3.33, respectively. This study provides direct evidence that the color of a seedless pearl is mainly determined by the donor mussel, and both the host mussel and the aquaculture environment have a negligible role in the determination of pearl color.

Kong, J., Shen, C.J., Ye, R.H., 2013. Analytical research on the tidally-induced groundwater wave propagation mechanism in coastal aquifers. With increasingly more attention paid to coastal environment, research on the interaction between subsurface and surface water has become a hot subject. Being different from surface water, tidally-induced groundwater moves slower with special over-height far away from the coastal line, which is higher than the mean sea level. Such a special hydrodynamic characteristic hints the special propagation mechanism is different from traditional surface wave. In order to reveal the tidally-induced groundwater wave propagation mechanism and analyze the influence of latent coastal beach profile variation because of mean sea level rise, theoretical research is focused on a newly derived high-order analytical solution corresponding to non-linear Boussinesq equation applied on sloping beach. Research indicates that: Firstly, the tidal induced groundwater wave energy mainl...

Eight novel polymorphic microsatellite loci developed from a microsatellite enriched genomic library, are presented for the Chinese pond turtle (Chinemys reevesii). We screened 30 individuals from three populations and detected high levels of polymorphism for all eight loci with the number of alleles/locus ranging from 7 to 17 (average = 10.88). The values of expected and observed heterozygosities ranged from 0.703 to 0.920 and 0.321 to 0.966, respectively. These highly variable loci will provide a powerful molecular toolkit for studies of population structure, gene flow, and paternity assignment.

We characterized 15 polymorphic microsatellite loci for the giant spiny frog, Paa spinosa. These loci were highly polymorphic when screened in 38 individuals from two different populations, with nine to 23 alleles per locus. The range of observed and expected heterozygosities was 0.231-0.916 and 0.296-0.944, respectively. These polymorphic loci will be useful for assessing genetic diversity, population structure, gene flow, population assignment and determining paternity in the giant spiny frog.

Ye, R.; Song, Z.; Zhang, C.; He, Y.; Yu, S.; Kong, J., and Li, L., 2017. Analytical model for surface saltwater intrusion in estuaries. Based on the laterally averaged salt transport equation, a physically based surface saltwater intrusion model is presented for estimating the spatial distribution of salinity near the surface of the river along the estuary over high-water slack, low-water slack, and tidal-average conditions. The model is applied to simulate steady-state salinity profiles on the water surface of the Modaomen Estuary of the Pearl River delta in China. The results indicate that this model describes the surface salt profiles reasonably well and is capable of forecasting surface saltwater intrusion.

The hydrology of the Pearl River Estuary is controlled both by river discharge and tide, where water and sediment move through eight outlets (mouths) into the sea. Using numerical modeling, this paper examines the characteristics of tidal movement in Pearl River Estuary. Results showed an amphidromic point near Modaomen mouth, and river runoff flows down. From marine dynamics point of view, Modaomen mouth is the main channel for water and sediment transportation of Pearl River. Using the tidal energy, we discuss the change of the sediment near the several entrances during the flood and dry seasons.