Bayesian model predicts the aboveground biomass of Caragana microphylla in sandy lands better than OLS regression models

回归模型可用于预测森林生态系统地上生物量,其中最为常用的是最小二乘回归模型。在预测灌木,尤其是多茎灌木的地上生物量 时,最小二乘法与贝叶斯方法的比较很少被研究。我们开发了小叶锦鸡儿(Caragana microphylla Lam.)生物量预测模型。小叶锦鸡儿是科尔 沁沙地广泛分布的多茎灌木,对减少风蚀、固定沙丘具有重要作用。本研究建立6种表征生物量的异速增长模型,并基于统计标准选择 在预测生物量方面表现最佳的1种,然后分别用最小二乘法与贝叶斯方法对模型中的参数进行估计。参数估计过程中用自助法考察样本量大 小的影响,同时区分测试集与训练集。最后,我们比较了最小二乘法与贝叶斯方法在小叶锦鸡儿地上生物量预测中的表现。异速增长的6个 模型均达到显著水平,其中幂指数为1的模型表现最佳。研究结果表明,采用无先验信息与有先验信息的贝叶斯方法进行估计,得到的均 方误差在测试集上低于最小二乘法。另外,基径作为预测变量在最小二乘法与贝叶斯方法中均不显著,表明在生物量预测模型中应谨慎选 择合适变量。本研究强调贝叶斯方法、自助法和异速增长模型相结合能够提升沙地灌木生物量预测模型的准确度。     

中国旅游生态足迹研究可视化分析

旅游生态足迹是一种定量测算旅游可持续发展的方法,对于全面评估旅游者对旅游地的生态环境响应有重要理论意义和现实价值。基于中国知网2004—2017年关于旅游生态足迹的面板数据,运用CiteSpace信息可视化分析软件,绘制国内旅游生态足迹的发文作者、发文机构以及关键词等内容的科学知识图谱,通过梳理该研究领域的发展现状,探讨其未来发展路径和研究方向。研究结果表明:(1)国内旅游生态足迹的发文数量整体呈现出增长趋势,研究作者群体逐渐增多,核心研究团队逐渐突显,但各研究机构的科研能力差距较大;(2)研究涉及学科领域较广,学科交叉性、多样性、综合性等特征明显;(3)旅游生态足迹模型、旅游生态承载力以及旅游可持续发展是该研究领域的核心关键词,区域旅游生态足迹的动态演变过程及其驱动机制、旅游生态系统服务的多功能性和旅游可持续发展路径等方面,将会是未来需要长期关注的研究话题。     

基于GIS的梭梭年轮测量方法

年轮信息对重建气候和预测环境的动态变化有重要意义。为准确测量梭梭年轮间距等各项参数,研究基于GIS对扫描后的梭梭圆盘PS图像赋予坐标系统,通过ENVI图像分类软件结合GIS测量工具,完成梭梭年轮间距测量;利用WinDENDRO年轮分析系统验证测量结果的准确性。结果表明: 两种方法测量结果差异不显著(P=0.63),配对平均值差值为0.87 μm,测量结果准确可信。研究构建的方法可以用于梭梭年轮间距测量,并为面积、周长等年轮参数的自动化测量奠定了基础。该方法也可替代现有专业树木年轮分析系统用于部分年轮参数测量。研究结果有助于梭梭树轮气候学分析和种群年龄结构调查。     

A comment on Farwell (2012): brain fingerprinting: a comprehensive tutorial review of detection of concealed information with event-related brain potentials

In a recent issue of Cognitive Neurodynamics Farwell (Cogn Neurodyn 6:115–154, 2012) published a comprehensive tutorial review of the use of Event Related Brain Potentials (ERP) in the detection of concealed information. Farwell’s review covered much of his own work employing his “brain fingerprinting” technology. All his work showed a 100 % accuracy rate in detecting concealed information. We argue in this comment that Farwell (Cogn Neurodyn 6:115–154, 2012) is misleading and misrepresents the scientific status of brain fingerprinting technology.     

Classification of hospital pathways in the management of cancer: Application to lung cancer in the region of burgundy

Context: The evaluation of national cancer plans is an important aspect of their implementation. For this evaluation, the principal actors in the field (doctors, nurses, etc.) as well as decision-makers must have access to information that is reliable, synthetic and easy to interpret, and which reflects the implementation process in the field. We propose here a methodology to make this type of information available in the context of reducing inequalities with regard to access to healthcare for patients with lung cancer in the region of Burgundy. Methods: We used the national medico-administrative DRG-type database, which gathers together all hospital stays. By using this database, it was possible to identify and reconstruct the care management history of these patients. That is, by linking together all attended hospitals, sorted chronologically. Eligible patients were at least 18 years old, whatever the gender and had undergone surgery for their lung cancer. They had to be residents of Burgundy at the time of the first operation between 2006 and 2008. Patient's pathway was defined as the sequence of all attended hospitals (hospital stays) during the year of follow up linked together using an anonymised patient identifier. We then constructed a pathway typology of pathway using an unsupervised clustering method, and conducted a spatial analysis of this typology. Results: Between 2006 and 2008, we selected 495 patients in the 4 administrative departments of the Burgundy region. They accounted for a total of 3821 stays during the year of follow-up. There were 393 men (79%) and the mean age was 64 (95% confidence interval: 63–65) years. We reconstructed 94 pathways (about five per patient). Here, neighbourhood's cares accounted for 41% of them, while 44% included a surgical intervention outside the region of Burgundy. We constructed a pathway typology with five classes. Spatial analysis showed that the vast majority of initial surgeries took place in the major regional centres. Conclusion: The construction of a pathway typology leads to better understanding of the reasoning that lies behind the movements of patients. It opens the way for analysis of the collaboration between the different healthcares establishments attended, which should bring to light associations that need to be developed.     

Decreased expression of sirtuin 6 is associated with release of high mobility group box-1 after cerebral ischemia

Sirtuin 6 (SIRT6) belongs to the sirtuin family of NAD⁺-dependent deacetylases and has been implicated in the regulation of metabolism, inflammation, and aging. Here, we found that SIRT6 was predominantly expressed in neuronal cells throughout the entire brain. Ischemia models using transient middle cerebral artery occlusion in rats and oxygen/glucose deprivation (OGD) in SH-SY5Y neuronal cells showed that ischemia reduced SIRT6 expression and induced the release of high mobility group box-1 (HMGB1) from cell nuclei. The reduced expression of SIRT6 via treatment with SIRT6 siRNA dramatically enhanced the OGD-induced release of HMGB1 in SH-SY5Y cells. Together, our data suggest that SIRT6 may serve as a potential therapeutic target for HMGB1-mediated inflammation after cerebral ischemia.     

Haplotype distribution in the GLI3 gene and their associations with growth traits in cattle

The glioma-associated oncogene family zinc finger 3 gene (GLI3) mediates in all vertebrates hedgehog (Hh) signaling that plays an essential role in the induction and patterning of numerous cell types during invertebrate and vertebrate development. In this study, a total of 6 single nucleotide polymorphisms (SNPs: 1–6) were identified by polymerase chain reaction–single stranded conformational polymorphism (PCR–SSCP) and DNA pool sequencing, including all 13 exons and 12 exon–intron boundaries within the bovine GLI3 gene. 16 haplotypes and 13 combined genotypes were revealed and the linkage disequilibrium was assessed in 708 individuals representing three main cattle breeds from China. The statistical analyses indicated that the SNP2, 3 and 4 are associated with the body weight at birth and 6 months in Nanyang cattle population (P < 0.05). No significant association was detected between 11 combined genotypes and body weight at five different ages. Our results provide evidence that polymorphisms in the GLI3 gene are associated with growth traits, and may be used for marker-assisted selection in beef cattle breeding program.     

Identification of the highly accumulated microRNA*s in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa)

Plant microRNAs (miRNAs) are crucial for the regulation of gene expression, which is involved in almost all the important biological processes. In the cytoplasm, the miRNA strand is selectively incorporated into a specific Argonaute (AGO)-associated gene silencing complex, while the miRNA* is degraded rapidly. Thus, most miRNA*s were thought to be biologically meaningless. Interestingly, several recent reports in both plants and animals have shaken this notion. Many miRNA*s were demonstrated to possess regulatory roles in gene expression. However, the low accumulation levels of most miRNA*s raise the question whether the activities of this small RNA (sRNA) species are widespread in plants. Here, by using publicly available sRNA high-throughput sequencing data, we found that the accumulation levels of several miRNA*s could be much higher than those of their miRNA partners in certain organs, mutants and/or AGO-associated silencing complexes of both Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa). Based on target prediction and degradome sequencing data-based validation, some of these highly accumulated miRNA*s were indicated to possess cleavage-based potential regulatory role on certain targets. Besides, some interesting biological interpretations were obtained based on the accumulation patterns of the miRNA*s, the annotations of the target genes, and literature mining. Taken together, the expanded list of the highly accumulated miRNA*s along with their potential target genes discovered in this study further strengthened the current notion that certain members of the miRNA* species are biologically relevant, which needs further inspection.     

Effect of genetic variations within the SH2B2 gene on the growth of Chinese cattle

As an adaptor protein, apart from potentiating Janus kinase 2 (JAK2) activation and promoting the insulin signaling pathway, Src homology 2 B 2 (SH2B2) indirectly takes part in the regulation of glucose uptake through the c-Cb1/CAP/TC10 pathway, which can in turn affect growth. In this study, we identified a 4 bp indel mutation and three single nucleotide polymorphisms (SNPs) within the SH2B2 gene in 959 individuals from five Chinese cattle breeds by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing. Based on the four variations, 12 haplotypes were identified. Additionally, there was a tendency that in every population pair-wise linkages increased progressively from V1–V2 to V3–V4. By association analysis, positive effects of genotypes CC and CT (snp1220 locus), DI (4 bp indel locus), and CC (snp21049 locus) on growth traits were obtained. Furthermore, when combined, individuals with the combination CCDITTCC showed the best performance at an early age. These results were suggestive of an association of snp1220, 4 bp indel and snp12049 with growth performance in Nanyang cattle, indicating possibly the candidate role of the SH2B2 gene in marker assisted selection in a beef cattle breeding program.