Receiver Operating Characteristic (ROC)

接收机工作特性 (ROC)
  • 文章类型: Journal Article
    神经性疼痛(NP)总是伴有抑郁症状,严重影响身心健康。在这项研究中,我们鉴定了NP和重度抑郁障碍(MDD)的共同hub基因(Co-hub基因)和相关免疫细胞,以确定它们是否具有共同的病理和分子机制.从基因表达综合(GEO)数据库下载NP和MDD表达数据。提取了NP和MDD的常见差异表达基因(Co-DEGs),并挖掘了hub基因和hub节点。协同DEG,集线器基因,分析和枢纽节点的基因本体论(GO)和京都基因和基因组百科全书(KEGG)富集。最后,集线器节点,并对基因进行分析,获得Co-hub基因。我们绘制了受试者工作特征(ROC)曲线,以评估Co-hub基因对MDD和NP的诊断影响。我们还通过ssGSEA鉴定了免疫浸润细胞成分并分析了它们之间的关系。对于GO和KEGG富集分析,93个Co-DEGs与生物过程(BP)相关,如纤维蛋白溶解,细胞组成(CC),如三级颗粒,和路径,如补语,和凝结级联。差异基因表达分析显示Co-hub基因ANGPT2、MMP9、PLAU、和TIMP2。根据ANGPT2和MMP9的表达对NP的诊断有一定的准确性。对免疫细胞成分差异的分析表明,激活的树突状细胞丰富,效应记忆CD8+T细胞,记忆B细胞,两组的调节性T细胞,具有统计学意义。总之,我们确定了6个与NP和MDD相关的Co-hub基因和4种免疫细胞类型。需要进一步的研究来确定这些基因和免疫细胞作为NP和MDD中潜在的诊断标志物或治疗靶标的作用。
    Neurological pain (NP) is always accompanied by symptoms of depression, which seriously affects physical and mental health. In this study, we identified the common hub genes (Co-hub genes) and related immune cells of NP and major depressive disorder (MDD) to determine whether they have common pathological and molecular mechanisms. NP and MDD expression data was downloaded from the Gene Expression Omnibus (GEO) database. Common differentially expressed genes (Co-DEGs) for NP and MDD were extracted and the hub genes and hub nodes were mined. Co-DEGs, hub genes, and hub nodes were analyzed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, the hub nodes, and genes were analyzed to obtain Co-hub genes. We plotted Receiver operating characteristic (ROC) curves to evaluate the diagnostic impact of the Co-hub genes on MDD and NP. We also identified the immune-infiltrating cell component by ssGSEA and analyzed the relationship. For the GO and KEGG enrichment analyses, 93 Co-DEGs were associated with biological processes (BP), such as fibrinolysis, cell composition (CC), such as tertiary granules, and pathways, such as complement, and coagulation cascades. A differential gene expression analysis revealed significant differences between the Co-hub genes ANGPT2, MMP9, PLAU, and TIMP2. There was some accuracy in the diagnosis of NP based on the expression of ANGPT2 and MMP9. Analysis of differences in the immune cell components indicated an abundance of activated dendritic cells, effector memory CD8+ T cells, memory B cells, and regulatory T cells in both groups, which were statistically significant. In summary, we identified 6 Co-hub genes and 4 immune cell types related to NP and MDD. Further studies are needed to determine the role of these genes and immune cells as potential diagnostic markers or therapeutic targets in NP and MDD.
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  • 文章类型: Journal Article
    该研究利用傅立叶变换红外(FTIR)光谱结合化学计量学研究真性红细胞增多症(PV)患者血清中的蛋白质组成和结构变化。主成分分析(PCA)揭示了不同的生化特性,强调磷脂的吸光度升高,酰胺,与健康对照相比,PV患者的血脂。酰胺I/酰胺II和酰胺I/酰胺III的比例表明蛋白质结构的改变。支持向量机分析和接收器工作特性曲线确定酰胺I是PV的关键预测因子,达到100%的准确度,灵敏度,和特异性,而酰胺III显示较低的预测值(70%)。PCA分析表明PV患者和对照组之间的有效区分,关键波数包括酰胺II,酰胺I,和CH脂质振动。这些发现强调了FTIR光谱用于诊断和监测PV的潜力。
    The study utilized Fourier transform infrared (FTIR) spectroscopy coupled with chemometrics to investigate protein composition and structural changes in the blood serum of patients with polycythemia vera (PV). Principal component analysis (PCA) revealed distinct biochemical properties, highlighting elevated absorbance of phospholipids, amides, and lipids in PV patients compared to healthy controls. Ratios of amide I/amide II and amide I/amide III indicated alterations in protein structures. Support vector machine analysis and receiver operating characteristic curves identified amide I as a crucial predictor of PV, achieving 100% accuracy, sensitivity, and specificity, while amide III showed a lower predictive value (70%). PCA analysis demonstrated effective differentiation between PV patients and controls, with key wavenumbers including amide II, amide I, and CH lipid vibrations. These findings underscore the potential of FTIR spectroscopy for diagnosing and monitoring PV.
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  • 文章类型: Journal Article
    睡眠是一个基本的,生物生存的生理需求,是一个涵盖我们生命三分之一的过程。褪黑激素是一种在睡眠调节中起重要作用的激素。睡眠不足会影响大脑结构和功能。睡眠不足会导致大脑活动减少,对海马体和前额叶皮层有特别的负面影响。尽管蛋白质和脂质振动的重要作用,多糖,脂肪酸侧链官能团,以及大脑结构和功能中酰胺的比例,与褪黑素暴露相比,暴露于温和处理睡眠剥夺模型的大脑化学特征仍未探索。因此,本研究,旨在研究这些区域的分子概况使用FTIR光谱测量分析基于脂质组学方法与化学计量学和多变量分析来评估海马脂质组成的变化,大脑的前额区。在这项研究中,C57BL/6J小鼠被随机分配到对照组或睡眠剥夺组,产生四个实验组:对照(C)(n=6),对照+褪黑素(C+M)(n=6),睡眠剥夺(S)(n=6),和睡眠剥夺+褪黑素(S+M)(n=6)。每天早晨通过腹膜内注射褪黑激素(10mg/kg)或载体溶液(%1乙醇+盐水)进行干预,而S组和SM组每天使用温和处理方法进行6小时的睡眠剥夺。将所有小鼠单独饲养在笼子中,在12小时的明暗周期内随意获取食物和水。结果显示,大脑区域受到失眠的影响。磷脂的结构,已更改。然而,在海马和前额叶皮质组织中不仅观察到脂质的变化,而且观察到酰胺的变化。此外,FTIR结果表明,褪黑激素影响从对照组和睡眠剥夺组收集的皮质和海马中的脂质以及酰胺组分。
    Sleep is a basic, physiological requirement for living things to survive and is a process that covers one third of our lives. Melatonin is a hormone that plays an important role in the regulation of sleep. Sleep deprivation affect brain structures and functions. Sleep deprivation causes a decrease in brain activity, with particularly negative effects on the hippocampus and prefrontal cortex. Despite the essential role of protein and lipids vibrations, polysaccharides, fatty acid side chains functional groups, and ratios between amides in brain structures and functions, the brain chemical profile exposed to gentle handling sleep deprivation model versus Melatonin exposure remains unexplored. Therefore, the present study, aims to investigate a molecular profile of these regions using FTIR spectroscopy measurement\'s analysis based on lipidomic approach with chemometrics and multivariate analysis to evaluate changes in lipid composition in the hippocampus, prefrontal regions of the brain. In this study, C57BL/6J mice were randomly assigned to either the control or sleep deprivation group, resulting in four experimental groups: Control (C) (n = 6), Control + Melatonin (C + M) (n = 6), Sleep Deprivation (S) (n = 6), and Sleep Deprivation + Melatonin (S + M) (n = 6). Interventions were administered each morning via intraperitoneal injections of melatonin (10 mg/kg) or vehicle solution (%1 ethanol + saline), while the S and S + M groups underwent 6 h of daily sleep deprivation from using the Gentle Handling method. All mice were individually housed in cages with ad libitum access to food and water within a 12-hour light-dark cycle. Results presented that the brain regions affected by insomnia. The structure of phospholipids, changed. Yet, not only changes in lipids but also in amides were noticed in hippocampus and prefrontal cortex tissues. Additionally, FTIR results showed that melatonin affected the lipids as well as the amides fraction in cortex and hippocampus collected from both control and sleep deprivation groups.
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  • 文章类型: Journal Article
    汉密尔顿抑郁量表(HDRS-17)和汉密尔顿焦虑量表(HARS-14)已被公认为评估抑郁和焦虑严重程度的黄金标准。这些量表在预测抑郁症和焦虑症方面的特异性和敏感性是临床和研究领域的问题。本研究提出了一种新的模型来增强HDRS-17和HARS-14预测失眠症状的敏感性和特异性。食欲不振,精神病患者的性欲丧失。
    这项研究包括1507名诊断为双相情感障碍的患者,抑郁症,恐慌症,强迫症,和广泛性焦虑症。HDRS-17和HARS-14被用作预测患者睡眠的预测量表,食欲,还有性欲.使用接收器工作特性(ROC)计算灵敏度和特异性。进行Logistic回归以提高预测值。Logistic回归模型的预测价值不理想,因此,我们为每个症状诊断亚组设计了一个转换表.然后使用新的联合ROC模型重新计算每个症状诊断亚组的2个量表的敏感性和特异性。结果是一个预测表,供临床医生使用。
    观察到新的统计模型,联合中华民国,增加了HDRS-17和HARS-14的敏感性和特异性。
    :根据HDRS和HARS的评估结果,联合ROC方法用于更好地预测症状的存在。
    UNASSIGNED: The Hamilton Depression Rating Scale (HDRS-17) and the Hamilton Anxiety Rating Scale (HARS-14) have been acknowledged as gold standards in evaluating the severity of depression and anxiety. The specificity and sensitivity of these scales in predicting somatic complaints of depression and anxiety are issues in both clinical and research areas. The present study proposes a new model to enhance the sensitivity and specificity of HDRS-17 and HARS-14 for predicting symptoms of insomnia, inappetence, and loss of libido in psychiatric patients.
    UNASSIGNED: This study included 1507 patients diagnosed withbipolar disorder, depression, panic disorder, obsessive-compulsive disorder, and generalized anxiety disorder. The HDRS-17 and the HARS-14 were utilized as predictive scales for the prediction of patients\' sleep, appetite, and libido. The sensitivity and specificity were computed using the receiver operating characteristic (ROC). Logistic regression was performed to enhance the predictive values. The predictive value of the logistic regression model was not satisfactory, and a conversion table was therefore designed for each symptom-diagnosis subgroup. The new joint ROC model was then used to recalculate the sensitivity and specificity of the 2 scales for each symptom-diagnosis subgroup. The outcome is a prediction table, presented for use by clinicians.
    UNASSIGNED: It was observed that the new statistical model, the joint ROC, increased the sensitivity and specificity of the HDRS-17 and the HARS-14.
    UNASSIGNED: : Based on the results of the evaluations with the HDRS and the HARS, the joint ROC method was developed to better predict the presence of symptoms.
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  • 文章类型: Journal Article
    克拉霉素耐药性的上升破坏了幽门螺杆菌(H.幽门螺杆菌)治疗效果。我们旨在确定克拉霉素的最低抑制浓度(MIC)水平,并确定23S核糖体亚基(23SrRNA)中的特定突变位点,以预测克拉霉素铋四联疗法(阿莫西林1g,克拉霉素500毫克,雷贝拉唑10毫克,和胶体果胶铋200毫克)。
    我们包括以前没有接受克拉霉素治疗的成人幽门螺杆菌患者,作为初始或抢救治疗。排除了青霉素过敏,最近使用相关药物,严重的疾病,或者无法合作。患者接受了14天的克拉霉素铋四联疗法。根除前在内镜检查期间获得胃粘膜标本。使用E-test方法测定对阿莫西林和克拉霉素的MIC。受试者工作特征(ROC)曲线有助于找到最佳的克拉霉素抗性MIC断点。通过Sanger测序鉴定幽门螺杆菌23SrRNA的遗传序列。(ChiCTR2200061476)。
    在招募的196名患者中,92符合符合方案(PP)人群的纳入标准。整体意向治疗(ITT)根除率为80.00%(84/105),而改良意向治疗(MITT)和PP根除率分别为90.32%(84/93)和91.30%(84/92)。没有观察到阿莫西林耐药性,但克拉霉素耐药率为36.19%(38/105),35.48%(33/93),ITT中的34.78%(33/92),米特,和PP种群分别。与传统克拉霉素耐药断点0.25μg/mL相比,12μg/mL的MIC阈值预测更好的根除。在23SrRNA基因152个位点的173个突变中,只有2143A>G突变可以预测根除结果(p<0.000)。
    对升高的MIC值的解释在敏感性测试中至关重要,而不是二进制的“易感”或“抗性”分类。2143A>G突变在预测根除结果方面具有有限的特异性,需要进一步研究与克拉霉素抗性相关的其他突变位点。
    UNASSIGNED: Rising clarithromycin resistance undermines Helicobacter pylori (H. pylori) treatment efficacy. We aimed to determine clarithromycin\'s minimum inhibitory concentration (MIC) levels and identify specific mutation sites in the 23S ribosomal subunit (23S rRNA) that predict treatment outcomes in a 14-day regimen of clarithromycin bismuth quadruple therapy (amoxicillin 1g, clarithromycin 500 mg, rabeprazole 10 mg, and colloidal bismuth pectin 200 mg).
    UNASSIGNED: We included adult H. pylori patients who hadn\'t previously undergone clarithromycin-based treatment, either as initial or rescue therapy. Exclusions were made for penicillin allergy, recent use of related medications, severe illnesses, or inability to cooperate. Patients underwent a 14-day clarithromycin bismuth quadruple therapy. Gastric mucosa specimens were obtained during endoscopy before eradication. MIC against amoxicillin and clarithromycin was determined using the E-test method. The receiver operating characteristic (ROC) curve helped to find the optimal clarithromycin resistance MIC breakpoint. Genetic sequences of H. pylori 23S rRNA were identified through Sanger Sequencing. (ChiCTR2200061476).
    UNASSIGNED: Out of 196 patients recruited, 92 met the inclusion criteria for the per-protocol (PP) population. The overall intention-to-treat (ITT) eradication rate was 80.00 % (84/105), while the modified intention-to-treat (MITT) and PP eradication rates were 90.32 % (84/93) and 91.30 % (84/92) respectively. No amoxicillin resistance was observed, but clarithromycin resistance rates were 36.19 % (38/105), 35.48 % (33/93), and 34.78 % (33/92) in the ITT, MITT, and PP populations respectively. Compared with the traditional clarithromycin resistance breakpoint of 0.25 μg/mL, a MIC threshold of 12 μg/mL predicted better eradication. Among 173 mutations on 152 sites in the 23S rRNA gene, only the 2143A > G mutation could predict eradication outcomes (p < 0.000).
    UNASSIGNED: Interpretation of elevated MIC values is crucial in susceptibility testing, rather than a binary \"susceptible\" or \"resistant\" classification. The 2143A > G mutation has limited specificity in predicting eradication outcomes, necessitating further investigation into additional mutation sites associated with clarithromycin resistance.
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  • 文章类型: Journal Article
    接收器操作特征(ROC)曲线下面积(AUC)是用于量化和比较二元分类器的标准度量。现实世界的应用程序通常需要分类为多个(两个以上)类。对于产生类成员资格分数的多类分类器,一种流行的多类AUC(MAUC)变体是平均成对AUC值[1]。由于复杂的相关模式,MAUC的方差通常使用重采样技术进行数值估计。这项工作是DeLong的二进制AUC分析[2]的非参数方法对MAUC的推广。我们首先推导出单个MAUC内成对AUC的协方差矩阵的封闭形式表达式。然后通过删除高阶项,我们得到了一个紧凑的近似协方差矩阵,矩阵分解形式,然后作为单个MAUC方差估计的基础。我们进一步扩展这种方法来估计由多个竞争分类器产生的相关MAUC的协方差。对于二进制相关AUC的特殊情况,我们的结果与德隆的结果一致。我们的数值研究证实了方差和协方差估计的准确性。我们在GitHub(https://tinyurl.com/euj6wvsz)上提供了相关MAUC的拟议协方差估计的源代码,以便机器学习和统计分析软件包轻松采用它来量化和比较多类分类器。
    The area under the Receiver Operating Characteristic (ROC) curve (AUC) is a standard metric for quantifying and comparing binary classifiers. Real world applications often require classification into multiple (more than two) classes. For multi-class classifiers that produce class membership scores, a popular multi-class AUC (MAUC) variant is to average the pairwise AUC values [1]. Due to the complicated correlation patterns, the variance of MAUC is often estimated numerically using resampling techniques. This work is a generalization of DeLong\'s nonparameteric approach for binary AUC analysis [2] to MAUC. We first derive the closed-form expression of the covariance matrix of the pairwise AUCs within a single MAUC. Then by dropping higher order terms, we obtain an approximate covariance matrix with a compact, matrix factorization form, which then serves as the basis for variance estimation of a single MAUC. We further extend this approach to estimate the covariance of correlated MAUCs that arise from multiple competing classifiers. For the special case of binary correlated AUCs, our results coincide with that of DeLong. Our numerical studies confirm the accuracy of the variance and covariance estimates. We provide the source code of the proposed covariance estimation of correlated MAUCs on GitHub (https://tinyurl.com/euj6wvsz) for its easy adoption by machine learning and statistical analysis packages to quantify and compare multi-class classifiers.
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  • 文章类型: Journal Article
    这项回顾性研究是在台湾南部的医疗中心进行的,目的是评估HendrichII跌倒风险模型(HIIFRM)预测跌倒的准确性。灵敏度,特异性,准确度,并使用受试者工作特性(ROC)曲线分析最佳截止点。使用来自电子病历和患者安全报告系统的信息进行数据分析。捕获303个跌倒事件和47,146个非跌倒事件。结果显示,在HIIFRM评分≥5的标准阈值下,跌倒组的中位数得分明显高于非跌倒组。HIIFRM得分超过5分的前三名单位为内科(50.6%),外科(26.5%),和肿瘤科病房(14.1%),表明这些地区跌倒的风险较高。ROC分析显示HIIFRM敏感性为29.5%,特异性为86.3%。曲线下面积(AUC)为0.57,表明预测跌倒的判别能力有限。在较低的截止分数(≥2)时,AUC为0.75(95%置信区间:0.666-0.706;p<0.0001),表明在预测跌倒方面具有可接受的辨别能力,另外识别出101个坠落事件。本研究强调在使用HIIFRM作为跌倒风险评估工具时选择适当的截止分数的重要性。这些发现对临床环境中的跌倒预防策略和患者护理具有重要意义。可能导致改善预后和患者安全。
    This retrospective study was conducted at a medical center in southern Taiwan to assess the accuracy of the Hendrich II Fall Risk Model (HIIFRM) in predicting falls. Sensitivity, specificity, accuracy, and optimal cutoff points were analyzed using receiver operating characteristic (ROC) curves. Data analysis was conducted using information from the electronic medical record and patient safety reporting systems, capturing 303 fall events and 47,146 non-fall events. Results revealed that at the standard threshold of HIIFRM score ≥5, the median score in the fall group was significantly higher than in the non-fall group. The top three units with HIIFRM scores exceeding 5 were the internal medicine (50.6%), surgical (26.5%), and oncology wards (14.1%), indicating a higher risk of falls in these areas. ROC analysis showed an HIIFRM sensitivity of 29.5% and specificity of 86.3%. The area under the curve (AUC) was 0.57, indicating limited discriminative ability in predicting falls. At a lower cutoff score (≥2), the AUC was 0.75 (95% confidence interval: 0.666-0.706; p < 0.0001), suggesting acceptable discriminative ability in predicting falls, with an additional identification of 101 fall events. This study emphasizes the importance of selecting an appropriate cutoff score when using the HIIFRM as a fall risk assessment tool. The findings have implications for fall prevention strategies and patient care in clinical settings, potentially leading to improved outcomes and patient safety.
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  • 文章类型: Journal Article
    牛布鲁氏菌病,主要由流产布鲁氏菌引起,严重影响动物健康和人类福祉。准确的诊断对于设计知情的控制和预防措施至关重要。缺乏黄金标准测试使得确定最佳截止值和评估测试的诊断性能具有挑战性。在这项研究中,我们开发了一种新颖的贝叶斯潜类模型,该模型集成了二进制和连续测试结果,结合额外的固定(平价)和随机(农场)效应,通过最大化Youden指数来校准最佳临界值。我们检测了河南省两个地区6个奶牛场的651份血清样本,中国有四项血清学试验:玫瑰红试验,血清凝集试验,荧光偏振测定,和竞争性酶联免疫吸附测定。我们的分析表明,FPA和C-ELISA的最佳临界值为94.2mP和0.403PI,分别。四项测试的敏感度估计为69.7%至89.9%,而特异性估计值在97.1%和99.6%之间变化。河南省两个研究区域的真实患病率分别为4.7%和30.3%。与初产母牛相比,不同胎次组的阳性血清学状态的亲缘比在1.2至2.2之间。这种方法提供了一个强大的框架,用于在没有黄金标准测试的情况下验证连续和离散测试的诊断测试。我们的研究结果可以提高我们设计有针对性的疾病检测策略和实施有效控制中国奶牛场布鲁氏菌病的能力。
    Bovine brucellosis, primarily caused by Brucella abortus, severely affects both animal health and human well-being. Accurate diagnosis is crucial for designing informed control and prevention measures. Lacking a gold standard test makes it challenging to determine optimal cut-off values and evaluate the diagnostic performance of tests. In this study, we developed a novel Bayesian Latent Class Model that integrates both binary and continuous testing outcomes, incorporating additional fixed (parity) and random (farm) effects, to calibrate optimal cut-off values by maximizing Youden Index. We tested 651 serum samples collected from six dairy farms in two regions of Henan Province, China with four serological tests: Rose Bengal Test, Serum Agglutination Test, Fluorescence Polarization Assay, and Competitive Enzyme-Linked Immunosorbent Assay. Our analysis revealed that the optimal cut-off values for FPA and C-ELISA were 94.2 mP and 0.403 PI, respectively. Sensitivity estimates for the four tests ranged from 69.7% to 89.9%, while specificity estimates varied between 97.1% and 99.6%. The true prevalences in the two study regions in Henan province were 4.7% and 30.3%. Parity-specific odds ratios for positive serological status ranged from 1.2 to 2.2 for different parity groups compared to primiparous cows. This approach provides a robust framework for validating diagnostic tests for both continuous and discrete tests in the absence of a gold standard test. Our findings can enhance our ability to design targeted disease detection strategies and implement effective control measures for brucellosis in Chinese dairy farms.
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  • 文章类型: Journal Article
    人类引起的气候变化改变了植物物种的分布,为入侵物种重组生态适宜的栖息地。在这项研究中,我们确定了对Calyptocarpusvialis传播很重要的环境因素,印度西北部喜马拉雅地区(IHR)的一种新兴入侵杂草,以及当前气候情景下杂草的可能栖息地,以及使用MaxEnt生态位模型在几种代表性浓度途径(RCP)下的潜在范围扩展。预测具有0.894±0.010的高AUC(曲线下面积)值,并且测试与预期遗漏率之间具有显着的相关性。BIO15(降水季节性;38.8%)和BIO1(年平均温度;35.7%)对紫菜的可能分布影响最大,其次是海拔(11.7%)和土地覆盖(6.3%)。研究结果表明,与目前的情况不同,“高”和“非常高”的适宜性区域将上升,而不太适合的栖息地将消失。所有RCP(2.6、4.5、6.0和8.5)均表明“高”适宜性区域的C.vialis扩张,但RCP4.5预测收缩,和RCPs2.6、6.0和8.5预测“非常高”概率区域的扩展。C.vialis的电流分布为状态总面积的21.59%,具有“中等”到“高”的入侵适用性,但在RCP8.5场景下,到2070年,它可能会增长10%。该研究还表明,C.vialis可能在较低和较高海拔扩大其生态位。这项研究阐明了生物气候和地形因素如何影响生物多样性IHR中入侵物种的分散。政策制定者和土地使用管理人员可以利用这些数据来监测C.vialis热点,并制定科学合理的管理方法。
    Human-induced climate change modifies plant species distribution, reorganizing ecologically suitable habitats for invasive species. In this study, we identified the environmental factors that are important for the spread of Calyptocarpus vialis, an emerging invasive weed in the northwestern Indian Himalayan Region (IHR), along with possible habitats of the weed under current climatic scenarios and potential range expansion under several representative concentration pathways (RCPs) using MaxEnt niche modeling. The prediction had a high AUC (area under the curve) value of 0.894 ± 0.010 and a remarkable correlation between the test and expected omission rates. BIO15 (precipitation seasonality; 38.8%) and BIO1 (annual mean temperature; 35.7%) had the greatest impact on the probable distribution of C. vialis, followed by elevation (11.7%) and landcover (6.3%). The findings show that, unlike the current situation, \"high\" and \"very high\" suitability areas would rise while less-suited habitats would disappear. All RCPs (2.6, 4.5, 6.0, and 8.5) indicate the expansion of C. vialis in \"high\" suitability areas, but RCP 4.5 predicts contraction, and RCPs 2.6, 6.0, and 8.5 predict expansion in \"very high\" probability areas. The current distribution of C. vialis is 21.59% of the total area of the state, with \"medium\" to \"high\" invasion suitability, but under the RCP 8.5 scenario, it might grow by 10% by 2070. The study also reveals that C. vialis may expand its niche at both lower and higher elevations. This study clarifies how bioclimatic and topographic factors affect the dispersion of invasive species in the biodiverse IHR. Policymakers and land-use managers can utilize the data to monitor C. vialis hotspots and develop scientifically sound management methods.
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  • 文章类型: Journal Article
    接收器操作特征(ROC)曲线下面积(AUC)是用于量化和比较二元分类器的标准度量。DeLong等人[1]提出了一种流行的估计AUC和相关变量的方法-AUC的方差或多个相关AUC的完整协方差矩阵-这是基于曼·惠特尼双样本U统计量。方差估计器的偏差是假设检验和置信区间构造等应用中的重要因素-负偏方差估计器可能导致不正确的结论,正偏差是保守的,因此更可取。在这项工作中,我们证明了DeLong方法中的(协方差)估计总是有正偏差的。更具体地说,估计协方差的期望值与真实协方差之间的差异矩阵是正半正定矩阵。当样本量较小时,这种偏差是不可忽略的,并随着样本量的增加而迅速减少。我们的方法依赖于构建,从AUC内核,其(协方差矩阵与偏差一致的随机变量,从而确立索赔。我们还讨论了AUC方差估计的替代方法,这些方法可能会降低偏差。
    The area under the Receiver Operating Characteristic (ROC) curve (AUC) is a standard metric for quantifying and comparing binary classifiers. A popular approach to estimating the AUCs and the associated variabilities - the variance of the AUC or the full covariance matrix of multiple correlated AUCs - is the one proposed by DeLong et al [1], which is based on the Mann Whitney two-sample U-statistics. The bias of a variance estimator is an important factor in applications such as hypothesis testing and construction of confidence intervals - a negatively biased variance estimator may lead to incorrect conclusions, and a positive bias is conservative hence preferable. In this work, we show that the (co-)variance estimate in DeLong\'s approach is always positively biased. More specifically, the difference matrix between the expectation of the estimated covariance and the true covariance is a positive semi-definite matrix. This bias is non-negligible when the sample size is small, and quickly diminishes as the sample size increases. Our method relies on constructing, from the AUC kernel, a random variable whose (co-)variance matrix coincides with the bias, thereby establishing the claim. We also discuss alternative approaches to AUC variance estimation that may potentially reduce the bias.
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