New Generalizations of Cosmography Inspired by the Pade Approximant

The current accelerated expansion of the universe has been one of the most important fields in physics and astronomy since 1998. Many cosmological models have been proposed in the literature to explain this mysterious phenomenon. Since the nature and cause of the cosmic acceleration are still unknown, model-independent approaches to study the evolution of the universe are welcome. One of the powerful model-independent approaches is the so-called cosmography. It only relies on the cosmological principle, without postulating any underlying theoretical model. However, there are several shortcomings in the usual cosmography. For instance, it is plagued with the problem of divergence (or an unacceptably large error), and it fails to predict the future evolution of the universe. In the present work, we try to overcome or at least alleviate these problems, and we propose two new generalizations of cosmography inspired by the Pad\'e approximant. One is to directly parameterize the luminosity distance based on the Pad\'e approximant, while the other is to generalize cosmography with respect to a so-called $y_\beta$-shift $y_\beta=z/(1+\beta z)$, which is also inspired by the Pad\'e approximant. Then, we confront them with the observational data with the help of the Markov chain Monte Carlo (MCMC) code emcee, and find that they work fairly well.Comment: 16 pages, 3 tables, 5 figures, revtex4; v2: discussions added, Eur. Phys. J. C in press; v3: published versio

High Capacity of Nutrient Accumulation by Invasive Solidago canadensis in a Coastal Grassland

BackgroundSolidago canadensis is a notorious invasive species from North America that is spreading across East China. It is invading some coastal grasslands and replacing native grass species. The effects of the S. canadensis invasion on soil nutrient cycling in the grasslands remain unclear. This study examined the effects of the invasion of S. canadensis on macronutrient accumulation in species aboveground part and soil.MethodsAboveground biomass, macronutrient (N, P, and K) pools in biomass, litter mass and decomposition rates, soil macronutrient availability and soil microbial biomass and enzyme activity that were related to nutrient transformation were compared between plots invaded by S. canadensis and uninvaded plots dominated by three different native grass species: Phacelurus latifolius, Phragmites australis, and Imperata cylindrica.ResultsS. canadensis had higher aboveground biomass, higher leaf N, P, and K concentrations, and consequently, a larger macronutrient pool size in the standing biomass. S. canadensis also produced more litter with higher N, P, and K concentrations and faster decomposition rates. The S. canadensis invasion did not change the total N, P, and K concentration in the topsoil (0–10 cm), but the invasion did increase their availability. The S. canadensis invasion did not increase the total soil organic matter (TSOM) content but did increase the soil microbial biomass and the activities of urease, alkaline phosphatase, invertase, amylase, and glucosidase in the topsoil.ConclusionThe invasion of S. canadensis accelerates the macronutrient cycling rate via increases in aboveground productivity and nutrient accumulation in standing biomass, faster nutrient release from litter and higher soil microbial activity. An enhanced nutrient cycling rate may further enhance its invasiveness through a positive feedback on soil processes

Rare Gingival Metastasis by Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) uncommonly metastasizes to the gingiva, which always means a poor outcome. We reported a rare HCC case with multiple metastases to gingiva, lungs, and brain. A 60-year-old man was initially diagnosed as HCC with metastases to double lungs. He was subjected to a transarterial chemoembolization (TACE) (5-fluorouracil, 750 mg) and two cycles of intravenous chemotherapy (gemcitabine 1.8 g at days 1 and 8, oxaliplatin 200 mg at day 2, every 4 weeks). However, the volume of liver tumor still increased. A bean-size gingival nodule growing with occasional bleeding was also found. TACE (5-fluorouracil 750 mg, perarubicin 40 mg, cisplatin 20 mg) was performed again and an oral sorafenib therapy (400 mg, twice per day) was adopted. The disease maintained relatively stable for about 6 months until a second obvious progress. The gingival nodule was then palliatively excised and identified as a poorly differentiated metastatic HCC by histopathological examination. Best supportive treatments were made since the performance score was too bad. Finally, cerebral metastases occurred and the patient died of systemic failure. Upon review of previous reports, we discussed risk factors, clinical and pathological characteristics, treatments, and prognosis of gingival metastasis by HCC

A Novel Approach to Study Real-Time Dynamic Optimization Analysis and Simulation of Complex Mine Logistics Transportation Hybrid System with Belt and Surge Links

The mine logistics transportation system with belt and surge links is often formed by a complex hybrid dynamic system that consists of continuous and discrete links, and these parts can have the complex changes along with the mining engineering going on. Studying the hybrid system with belt and surge links to fully realize its beneficial functions is very significant. Until now, there have been many references studying the logistics transportation hybrid system with belt and surge links, and many concepts about it have been set up. However, in these references, complicated real-time dynamic changes of the hybrid system usually is studied. This paper presents a novel approach to study real-time dynamic optimization analysis and simulation problems of complex mine logistics transportation hybrid system, which can be used to make optimization design for this kind of complex hybrid system. The proposed method considered expressly complicated real-time dynamic changing of the hybrid system comparing with some existing references and can solve some optimization design problems of the hybrid system. In addition, this paper used statistical data of a real logistics transportation system with belt and surge bin on simulation and gets some useful conclusions. The application result shows that the presented method is valid