Improved Laguerre Spectral Methods with Less Round-off Errors and Better Stability

Laguerre polynomials are orthogonal polynomials defined on positive half line with respect to weight $e^{-x}$. They have wide applications in scientific and engineering computations. However, the exponential growth of Laguerre polynomials of high degree makes it hard to apply them to complicated systems that need to use large numbers of Laguerre bases. In this paper, we introduce modified three-term recurrence formula to reduce the round-off error and to avoid overflow and underflow issues in generating generalized Laguerre polynomials and Laguerre functions. We apply the improved Laguerre methods to solve an elliptic equation defined on the half line. More than one thousand Laguerre bases are used in this application and meanwhile accuracy close to machine precision is achieved. The optimal scaling factor of Laguerre methods are studied and found to be independent of number of quadrature points in two cases that Laguerre methods have better convergence speeds than mapped Jacobi methods.Comment: 19pages, 8 figure

Factors Influencing the Conversion of Arable Land to Urban Use and Policy Implications in Beijing, China

Rapid urban land expansion and the resulting arable land loss have put food security in China at risk. This paper investigates the characteristics and mechanism of arable land conversion in Beijing using a logistic model based on land-use data for 2001 and 2010. The results suggest that (1) arable land conversion tends to occur near built-up areas, city centers and major roads; (2) arable land that lies closer to irrigation canals and country roads is less likely to be converted to urban use; (3) arable land that is bigger in size and has a more regular shape has a lower probability of conversion to urban use; and (4) the Prime Farmland Protection policy and related land-use plan have played a positive role in preserving arable land, demonstrated by the probability for arable land conversion inside a prime farmland boundary is 63.9 percent less than for land outside the boundary. Based on these findings and on sustainable-development principles, we suggest that, rather than an exclusive focus on controlling the quantity of arable land, the location and characteristics of the arable land should be a primary consideration when designing urban policies and plans

Progress Report of the World Data Center for Seismology, Beijing

This paper presents in detail the project "Development and Service of World Data Center for Seismology, Beijing," including its background, construction tasks, main results, societal effects, and perspective for future development

Datasheet1_Effects of different traditional Chinese exercise in the treatment of essential hypertension: a systematic review and network meta-analysis.zip

BackgroundAs a therapy to prevent and treat essential hypertension (EH), traditional Chinese exercises (TCEs) were widely used in clinical practice. However, there is a lack of strictly comparison of the antihypertensive efficacy of different TCEs, which not conducive to the selection of the best and most optimal treatment. This study aimed to perform a network meta-analysis to objectively evaluate which TCE has the best effects in assisting with lowering blood pressure.MethodsPubMed, Embase, the Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), VIP, SinoMed and Wanfang Data were searched for all randomized controlled trials (RCTs) on TCEs for the treatment of EH published up to July 10, 2023. RoB2.0 tool was utilized to evaluate the quality of the RCTs. The network meta-analysis was performed by R 4.1.2 and Stata 17.0. Weighted mean difference (WMD) was calculated for continuous outcomes.ResultsA total of 29 studies, including 2,268 patients were included to analyze 6 different interventions. The network meta-analysis results presented that in comparison with control group, Tai Chi + antihypertensive medication [WMD = −10.18, 95% CI, (−14.94, −5.44)] is the most effective intervention for lowering systolic blood pressure (SBP), and Wuqinxi + antihypertensive medication [WMD = −10.36, 95% CI (−18.98, −1.66)] is the most effective intervention for lowering diastolic blood pressure (DBP).ConclusionTCEs combined with antihypertensive medication may be able to achieve more prominent antihypertensive effects with Tai Chi and Wuqinxi potentially being the higher-priority options. However, well-designed randomized studies are warranted to further verify currently conclusion.</p

PCR primers for the four genes.

<p>PCR primers for the four genes.</p

Annotation summary of the seven <i>P</i>. <i>mirabilis</i> strains investigated in this study.

<p>Annotation summary of the seven <i>P</i>. <i>mirabilis</i> strains investigated in this study.</p

Currently adopted molecular typing technologies of biomarker genes in the infectious bacterial strains.

<p>Currently adopted molecular typing technologies of biomarker genes in the infectious bacterial strains.</p

Comparative Screening of Digestion Tract Toxic Genes in <i>Proteus mirabilis</i>

<div><p><i>Proteus mirabilis</i> is a common urinary tract pathogen, and may induce various inflammation symptoms. Its notorious ability to resist multiple antibiotics and to form urinary tract stones makes its treatment a long and painful process, which is further challenged by the frequent horizontal gene transferring events in <i>P</i>. <i>mirabilis</i> genomes. Three strains of <i>P</i>. <i>mirabilis</i> C02011/C04010/C04013 were isolated from a local outbreak of a food poisoning event in Shenzhen, China. Our hypothesis is that new genes may have been acquired horizontally to exert the digestion tract infection and toxicity. The functional characterization of these three genomes shows that each of them independently acquired dozens of virulent genes horizontally from the other microbial genomes. The representative strain C02011 induces the symptoms of both vomit and diarrhea, and has recently acquired a complete type IV secretion system and digestion tract toxic genes from the other bacteria.</p></div