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Reestablishment of submerged macrophytes is considered important when restoring shallow eutrophic lakes. To improve water clarity and consequently the growth conditions of macrophytes, removal of plankti-benthivorous fish has been used. In sub-tropical shallow lakes, however, rapid recruitment of small fish, especially benthivores during restoration, may hamper early reestablishment of submerged macrophytes. Crucian carp ( Carassius carassius ) and Vallisneria natans are common species dominated in sub-tropical shallow lakes. To investigate the effect of small benthivorous fish on the growth of Vallisneria natans , a 28-day outdoor controlled experiment was undertaken in 12 mesocosms with three densities of Carassius carassius − low (10 g m −2 ), high (40 g m −2 ) and no fish (all in four replicates). The results showed that the fish significantly increased chlorophyll- a concentrations and periphyton biomass in both fish treatments, most significantly at high density for Chl a . This concurs with an increase in nutrient concentrations, likely mediated by fish sediment disturbance and excretion, and a reduction of zooplankton biomass (less algal grazing). Increased concentrations of inorganic suspended solids with increasing fish density further enhanced turbidity, causing shading of the macrophytes. Accordingly, the relative growth rate, ramet number and root/leaf ratio of V. natans decreased significantly at low and high fish density compared with the controls, but the effects did not depend on fish density. However, mean leaf length rose with increasing fish density, likely to allow the plants to obtain more light. Overall, our results show that not only large-bodied carp, as demonstrated frequently, but also small-sized crucian carp posed a constraint on submerged macrophyte reestablishment, and we conclude that crucian carp may hamper restoration efforts in sub-tropical shallow lakes. Restoration by biomanipulation should therefore target also small-sized crucian carp. [ABSTRACT FROM AUTHOR]

We define a (pseudo-)distance between graphs based on the spectrum of the normalized Laplacian. Since this quantity can be computed easily, or at numerically estimated, it is suitable for comparing in particular large graphs. Numerical experiments demonstrate that the spectral distance provides a practically useful measure of graph dissimilarity. The asymptotic behavior of the Laplacian spectrum furthermore yields a tool for classifying families of graphs in such a way that the distance of two graphs from the same family is bounded by O ( 1 / n ) in terms of size n of their vertex sets. [ABSTRACT FROM AUTHOR]

By assigning a probability measure via the spectrum of the normalized Laplacian to each graph and using L p Wasserstein distances between probability measures, we define the corresponding spectral distances d p on the set of all graphs. This approach can even be extended to measuring the distances between infinite graphs. We prove that the diameter of the set of graphs, as a pseudo-metric space equipped with d 1 , is one. We further study the behavior of d 1 when the size of graphs tends to infinity by interlacing inequalities aiming at exploring large real networks. A monotonic relation between d 1 and the evolutionary distance of biological networks is observed in simulations. [ABSTRACT FROM AUTHOR]

There has been an upsurge of research on complex networks in recent years. The purpose of this paper is to study the mathematical properties of the random pentagonal chain networks PE C n with the help of graph theory. Based on the networks PE C n , we first obtain the expected value expressions of the Gutman index, Schultz index, multiplicative degree-Kirchhoff index, and additive degree-Kirchhoff index, and then, we get the explicit expression formulas of their variances. Finally, we find that their limiting distributions all have the probabilistic and statistical significance of normal distribution. [ABSTRACT FROM AUTHOR]

Background: Malignant transformation of endometriosis in the rectovaginal septum is rare and usually misdiagnosed as a colorectal or gynecological tumor. We report a rare case of primary endometrioid adenocarcinoma of the rectovaginal septum with invasion of the rectum. Case presentation: A 57-year-old overweight woman presented with vaginal bleeding and self-reported left lower abdominal pain during the previous 2 weeks. Preoperative imaging showed a large pelvic mass with invasion of the rectum, suggestive of a gynecologic malignancy. Multiple endoscopic biopsies and immunohistochemical analyses of specimens was performed. The patient received joint gynecological-surgical laparotomy, and there were no intra- or postoperative complications. The histopathological diagnosis was rectovaginal endometrioid adenocarcinoma with rectum infiltration. The patient received adjuvant chemotherapy and achieved good treatment response, with no early complications. At 12 months after surgery, there was no evidence of recurrence. Conclusions: A high index of clinical suspicion is required for the diagnosis of endometrioid adenocarcinoma in the rectovaginal septum. Surgery combined with additional chemotherapy or radiotherapy seems to be a standard treatment, and hormonal therapy is optional. The efficacies of other therapies, including targeted medication and immunotherapy, are unknown. [ABSTRACT FROM AUTHOR]

Eutrophic shallow lakes have a high content of organic matter in the sediment that may be frequently resuspended. Whilst it is generally accepted that inorganic suspended matter has a negative effect on filtering-feeding bivalves in streams, it is unclear whether resuspended sediment in lakes with a high organic content will inhibit or support bivalve growth, the latter reflecting that resuspended sediment can increase food availability for Asian clams directly but also through release of nutrients, promoting the growth of phytoplankton. We conducted two experiments assessing the impact of different concentrations of total suspended solids (TSS) on the growth and feeding behaviour of Asian clams. We found that the growth rates in the low, medium and high treatments increased 12%, 36% and 53% respectively, when compared with the control with no sediment added. The effect on clearance rates of Asian clams differed amongst suspended fractions, and the clams showed significant preference for diatoms over other algae at high TSS. We conclude that an increase in TSS stimulated rather than reduced the growth of Asian clams, suggesting that eutrophication in shallow lakes provides more favourable conditions for the population expansion of Asian clams, an invasive species in many water bodies outside Asia. [ABSTRACT FROM AUTHOR]

A rapid, selective and sensitive method for the detection of caffeine in tea infusion and tea beverages are proposed by using 3,5-diaminobenzoic acid as a fluorescent probe. The 3,5-diaminobenzoic acid emits strong fluorescence around 410 nm under the excitation of light at 280 nm. Both the molecular electrostatic potential analysis and fluorescent lifetime measurement proved that the existence of caffeine can quench the fluorescence of 3,5-diaminobenzoic acid. Under the optimal experimental parameters, the 3,5-diaminobenzoic acid was used as a fluorescent probe to detect the caffeine aqueous solution. There exists a good linear relationship between the fluorescence quenching of the fluorescent probe and the concentration of caffeine in the range of 0.1–100 μM, with recovery within 96.0 to 106.2%, while the limit of detection of caffeine is 0.03 μM. This method shows a high selectivity for caffeine. The caffeine content in different tea infusions and tea beverages has been determined and compared with the results from HPLC measurement. [ABSTRACT FROM AUTHOR]

Rice as a paddy field crops, iron-containing materials application could induce its iron plaque formation, thereby affecting cadmium (Cd) transportation in the rhizosphere and its uptake in root. In this study, a hydroponic experiment was conducted to investigate the effects of three exogenous iron materials, namely nano-Fe 3 O 4 -modified biochar (BC–Fe), chelated iron (EDTA-Fe), and ferrous sulfate (FeSO 4), on the iron plaque formation on the surface of rice root, and to investigate the effects of formed iron plaque on the absorption, migration, and transportation of Cd and Fe in rice plant. The results showed that yellow-brown and brown iron plaque was formed on surface cells of the Fe-treated rice root, and some black particles were embedded in the iron plaque formed by BC-Fe. The proportion of crystallized iron plaque (31.8%–35.9%) formed by BC-Fe was much higher than that formed by EDTA-Fe and FeSO 4. The Cd concentrations in the crystallized iron plaque formed by BC-Fe were 7.64–13.0 mg·kg−1, and increased with the increasing of Fe concentrations in the plaque. The Cd translocation factor from root to stem (TF r-s) and the Cd translocation factor from stem to leaf (TF s-l) with BC-Fe treatment decreased by 84.7% and 80.0%, respectively. The results demonstrated that application BC-Fe promoted the formation of iron plaque and enhanced the sequestration of Cd and Fe in roots, thus reduced the transportation and accumulation of Cd in aerial rice tissues. [Display omitted] • BC-Fe promoted iron plaque formation and raised the proportion of crystallized iron plaque. • BC-Fe resulted in some black particles were embedded in iron plaque and outer root cells. • BC-Fe enhanced the sequestration of Cd and Fe level in rice root. • BC-Fe reduced the transportation and accumulation of Cd in aerial rice tissues. [ABSTRACT FROM AUTHOR]