ARMA

arma
  • 文章类型: Journal Article
    急性呼吸窘迫综合征(ARDS)改变了机械通气期间肺部充气的动力学。反复肺泡塌陷和扩张(RACE)使肺容易发生呼吸机诱导的肺损伤(VILI)。目前使用两种广泛的方法来最小化VILI:(1)低潮气量(LVT)和低中度呼气末正压(PEEP);(2)开放肺方法(OLA)。LVT方法试图保护已经开放的肺组织免受过度扩张,同时通过将塌陷的组织排除在机械通气周期之外,使其静止。相比之下,OLA试图重新膨胀潜在的可招募的肺,通常在数秒至数分钟的时间内,使用较高的PEEP来防止呼气末肺容积(EELV)和RACE的进行性损失。然而,即使有了这些保护策略,临床研究表明,在过去20年中,ARDS相关死亡率仍然高得令人无法接受,缺乏有效的干预措施.这些不同的干预措施证明受益的主要限制之一是观察到的ARDS的临床和病理异质性。我们开发了一种替代通气策略,称为时间控制自适应通气(TCAV)方法,用于应用气道压力释放通气(APRV)模式,它利用了不同的时间和压力依赖性塌陷和肺单位重新开放。TCAV方法是闭环系统,其中呼气持续时间个性化VT和EELV。通过被动呼气期间呼气流量曲线的斜率测量的呼吸系统顺应性(CRS)的变化来告知和调整TCAV的个性化。TCAV的两个潜在的有益特征是:(i)呼气持续时间针对给定患者的肺生理而个性化,通过阻止肺泡的进行性塌陷来促进肺泡的稳定,从而最大限度地减少重新开放的肺在下一次呼气中再次塌陷的时间,和(ii)在肺泡稳定后,在固定的充气压力下延长的吸气阶段随着每次呼吸逐渐重新打开少量组织。随后,密集塌陷的区域在几个小时内缓慢地逐渐张开,甚至几天。因此,TCAV有可能最小化VILI,降低ARDS相关发病率和死亡率。
    Acute respiratory distress syndrome (ARDS) alters the dynamics of lung inflation during mechanical ventilation. Repetitive alveolar collapse and expansion (RACE) predisposes the lung to ventilator-induced lung injury (VILI). Two broad approaches are currently used to minimize VILI: (1) low tidal volume (LVT) with low-moderate positive end-expiratory pressure (PEEP); and (2) open lung approach (OLA). The LVT approach attempts to protect already open lung tissue from overdistension, while simultaneously resting collapsed tissue by excluding it from the cycle of mechanical ventilation. By contrast, the OLA attempts to reinflate potentially recruitable lung, usually over a period of seconds to minutes using higher PEEP used to prevent progressive loss of end-expiratory lung volume (EELV) and RACE. However, even with these protective strategies, clinical studies have shown that ARDS-related mortality remains unacceptably high with a scarcity of effective interventions over the last two decades. One of the main limitations these varied interventions demonstrate to benefit is the observed clinical and pathologic heterogeneity in ARDS. We have developed an alternative ventilation strategy known as the Time Controlled Adaptive Ventilation (TCAV) method of applying the Airway Pressure Release Ventilation (APRV) mode, which takes advantage of the heterogeneous time- and pressure-dependent collapse and reopening of lung units. The TCAV method is a closed-loop system where the expiratory duration personalizes VT and EELV. Personalization of TCAV is informed and tuned with changes in respiratory system compliance (CRS) measured by the slope of the expiratory flow curve during passive exhalation. Two potentially beneficial features of TCAV are: (i) the expiratory duration is personalized to a given patient\'s lung physiology, which promotes alveolar stabilization by halting the progressive collapse of alveoli, thereby minimizing the time for the reopened lung to collapse again in the next expiration, and (ii) an extended inspiratory phase at a fixed inflation pressure after alveolar stabilization gradually reopens a small amount of tissue with each breath. Subsequently, densely collapsed regions are slowly ratcheted open over a period of hours, or even days. Thus, TCAV has the potential to minimize VILI, reducing ARDS-related morbidity and mortality.
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  • 文章类型: Journal Article
    耐碳青霉烯类鲍曼不动杆菌(CRAB)菌株可在整体健康受损的患者中引起严重且难以治疗的感染。CRAB菌株通过患者与患者的接触在医院环境中迅速传播,通过医疗设备和无生命的水库。居住在苏塞Sahloul大学医院重症监护病房(ICU)的患者中CRAB的发生,突尼斯很高。当前研究的目的是确定五个ICU病房中存在的物品表面以及在那里工作的医务人员是否可以作为CRAB菌株的储库。此外,分析了在采样活动期间居住在ICU中的患者的CRAB分离株,以与来自ICU环境的分离株进行基因组比较。总的来说,对206个项目进行了CRAB的筛选,其中27个(14%)被CRAB分离株污染。这些物品位于三个ICU的几个区域。在病房工作的54名接受筛查的人中有8名(15%)被手上的CRAB定居。居住在ICU中的患者感染了与在医院环境中恢复的菌株具有广泛的基因组相似性的CRAB菌株。这些菌株属于国际传播克隆(ST2)的三个子分支。还检测到在地中海盆地(ST85)出现的克隆。这些菌株是OXA-23或NDM-1生产者,并且由于armA基因的存在,也具有泛氨基糖苷抗性。Sahloul医院迫切需要采取卫生措施,以避免难以治疗的CRAB菌株进一步传播,并保护ICU病房中患者和工作人员的健康。
    Carbapenem-resistant Acinetobacter baumannii (CRAB) strains can cause severe and difficult-to-treat infections in patients with compromised general health. CRAB strains disseminate rapidly in nosocomial settings by patient-to-patient contact, through medical devices and inanimate reservoirs. The occurrence of CRAB in patients residing in the intensive care units (ICUs) of the Sahloul University hospital in Sousse, Tunisia is high. The objective of the current study was to determine whether the surfaces of items present in five ICU wards and the medical personnel there operating could serve as reservoirs for CRAB strains. Furthermore, CRAB isolates from patients residing in the ICUs during the sampling campaign were analyzed for genome comparison with isolates from the ICUs environment. Overall, 206 items were screened for CRAB presence and 27 (14%) were contaminated with a CRAB isolate. The items were located in several areas of three ICUs. Eight of the 54 (15%) screened people working in the wards were colonized by CRAB on the hands. Patients residing in the ICUs were infected with CRAB strains sharing extensive genomic similarity with strains recovered in the nosocomial environment. The strains belonged to three sub-clades of the internationally disseminated clone (ST2). A clone emerging in the Mediterranean basin (ST85) was detected as well. The strains were OXA-23 or NDM-1 producers and were also pan-aminoglycoside resistant due to the presence of the armA gene. Hygiene measures are urgent to be implemented in the Sahloul hospital to avoid further spread of difficult-to-treat CRAB strains and preserve health of patients and personnel operating in the ICU wards.
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  • 文章类型: Journal Article
    氨基糖苷类抗菌药物仍然是有价值的治疗选择,但是它们的有效性受到细菌16S核糖体RNA甲基转移酶(16S-RMTases)生产的威胁。在这项研究中,我们评估了在美洲大陆传播的革兰氏阴性菌中16S-RMTase基因的基因组流行病学.共有4877个16S-RMTase序列主要在肠杆菌和从人类分离的非发酵革兰氏阴性杆菌中被鉴定,动物,食物,和1931-2023年的环境。大多数鉴定的序列都是在美国发现的,巴西,加拿大,墨西哥,在过去五年(2018-2022年)中,16S-RMTase基因的患病率有所增加。最常携带16S-RMTase基因的三个物种是鲍曼不动杆菌,肺炎克雷伯菌,和大肠杆菌。ARMA基因是最普遍的,但其他16S-RMTase基因(例如,rmtB,rmtE,和rmtF)可能会在后台出现。美洲超过90%的16S-RMTase序列是在北美洲国家发现的,尽管16S-RMTase基因在中美洲和南美国家不太普遍,由于基因组数据有限,这些发现可能被低估.因此,应鼓励在低收入和中等收入国家采用“一个健康”方法进行以氨基糖苷类耐药为重点的全基因组序列研究.
    Aminoglycoside antimicrobials remain valuable therapeutic options, but their effectiveness has been threatened by the production of bacterial 16S ribosomal RNA methyltransferases (16S-RMTases). In this study, we evaluated the genomic epidemiology of 16S-RMTase genes among Gram-negative bacteria circulating in the American continent. A total of 4877 16S-RMTase sequences were identified mainly in Enterobacterales and nonfermenting Gram-negative bacilli isolated from humans, animals, foods, and the environment during 1931-2023. Most of the sequences identified were found in the United States, Brazil, Canada, and Mexico, and the prevalence of 16S-RMTase genes have increased in the last five years (2018-2022). The three species most frequently carrying 16S-RMTase genes were Acinetobacter baummannii, Klebsiella pneumoniae, and Escherichia coli. The armA gene was the most prevalent, but other 16S-RMTase genes (e.g., rmtB, rmtE, and rmtF) could be emerging backstage. More than 90% of 16S-RMTase sequences in the Americas were found in North American countries, and although the 16S-RMTase genes were less prevalent in Central and South American countries, these findings may be underestimations due to limited genomic data. Therefore, whole-genome sequence-based studies focusing on aminoglycoside resistance using a One Health approach in low- and middle-income countries should be encouraged.
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  • 文章类型: Journal Article
    背景:肺炎克雷伯菌的某些克隆复合物(CC),例如CC147(ST147和ST392)是全球blaNDM传播的主要驱动因素。ST147多次从我们的地理区域报告,但是它的种群动态和进化轨迹需要进一步研究。
    方法:使用各种生物信息学工具对在16个月监测期间回收的51株碳青霉烯类非敏感菌株以及3株高毒力肺炎克雷伯菌(hvKp)进行比较基因组分析。我们调查了我们的ST147菌株与全球和我们地理区域邻国公开提供的相应基因组的遗传邻近性。
    结果:虽然携带blaOXA-48的IncL/M质粒分布在不同的克隆中,blaNDM-1由25个CC147显性克隆中的20个传播,大部分从ICU中回收。NDM-1核心结构由可移动遗传元件(MGEs)的单个同工型[ΔISKpn26-NDM-TnAs3-ΔIS3000-Tn5403]包围,并位于ST392的68.7%的Col440I质粒上。然而,在ST147中鉴定了MGE的各种排列,包括MITESen1/MITESen1复合转座子或MITESen1/ISSen4/IS903B/IS5/ISEhe3在IncFIb(pB171)上的组合。似乎ST392在2018年传播blaNDM-1,然后在2019年从样本采集的中间到最后逐渐被ST147取代。ST147菌株具有最高数量的抗性标记,并且与四个在相同复制子类型上带有blaNDM-1的公共基因组表现出高度的遗传相似性。主要是,在最小生成树中,集群和孤立的邻国之间存在趋同。抗性标记/MGE的保守排列与甲基转移酶armA连接,该甲基转移酶armA嵌入ST147/ST48高风险克隆的8个分离株的1类整合子中。
    结论:我们的发现强调了伊朗肺炎克雷伯菌之间blaNDM-1传播的动态性质,该传播通过各种MGE组合发生克隆和水平。这是在全球范围内对伊朗ST147/NDM克隆的首次分析。
    BACKGROUND: Certain clonal complexes (CCs) of Klebsiella pneumoniae such as CC147 (ST147 and ST392) are major drivers of blaNDM dissemination across the world. ST147 has repeatedly reported from our geographical region, but its population dynamics and evolutionary trajectories need to be further studied.
    METHODS: Comparative genomic analysis of 51 carbapenem-nonsusceptible strains as well as three hypervirulent K. pneumoniae (hvKp) recovered during 16-months of surveillance was performed using various bioinformatics tools. We investigated the genetic proximity of our ST147 strains with publicly available corresponding genomes deposited globally and from neighbor countries in our geographic region.
    RESULTS: While IncL/M plasmid harboring blaOXA-48 was distributed among divergent clones, blaNDM-1 was circulated by twenty of the 25 CC147 dominant clone and were mostly recovered from the ICU. The NDM-1 core structure was bracketed by a single isoform of mobile genetic elements (MGEs) [ΔISKpn26-NDM-TnAs3-ΔIS3000-Tn5403] and was located on Col440I plasmid in 68.7% of ST392. However, various arrangements of MGEs including MITESen1/MITESen1 composite transposon or combination of MITESen1/ISSen4/IS903B/IS5/ISEhe3 on IncFIb (pB171) were identified in ST147. It seems that ST392 circulated blaNDM-1 in 2018 before being gradually replaced by ST147 from the middle to the end of sample collection in 2019. ST147 strains possessed the highest number of resistance markers and showed high genetic similarity with four public genomes that harbored blaNDM-1 on the same replicon type. Mainly, there was a convergence between clusters and isolated neighboring countries in the minimum-spanning tree. A conserved arrangement of resistance markers/MGEs was linked to methyltransferase armA which was embedded in class 1 integron in 8 isolates of ST147/ST48 high-risk clones.
    CONCLUSIONS: Our findings highlight the dynamic nature of blaNDM-1 transmission among K. pneumoniae in Iran that occurs both clonally and horizontally via various combinations of MGEs. This is the first analysis of Iranian ST147/NDM + clone in the global context.
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  • 文章类型: Multicenter Study
    在希腊,鲍曼不动杆菌对多种临床上重要的抗菌药物的耐药性已增加到非常高的比例,使他们中的大多数过时。这项研究的目的是确定从希腊不同医院收集的鲍曼不动杆菌分离株的分子流行病学和敏感性。从血培养物中分离的单患者鲍曼不动杆菌菌株(n=271),来自19家医院,在6个月内(2020年11月至2021年4月)进行了碳青霉烯酶的最低抑制浓度测定和分子测试,16SrRNA甲基转移酶和mcr基因检测及流行病学评价。所有分离物中的98.9%产生碳青霉烯酶OXA-23。绝大多数(91.8%)的OXA-23生产者都拥有arma,并主要(94.3%)分配给序列组G1,对应于ICII。在≤16mg/L时,安普霉素(EBL-1003)是抑制100%分离物的最具活性的药物,其次是头孢地洛,对至少86%的人有活性。米诺环素,粘菌素和氨苄西林-舒巴坦仅表现出稀疏的活性(S<19%),埃拉环素的活性分别比米诺环素和替加环素高8倍和2倍,通过比较它们的MIC50/90值。产生国际克隆II的鲍曼不动杆菌的OXA-23-ArmA似乎是希腊该生物的流行流行病学类型。头孢地洛可以为难以治疗的革兰氏阴性感染提供有用的替代方案,而阿普霉素(EBL-1003),结构独特的氨基糖苷目前在临床开发中,可能是一种非常有前途的药物,可以对抗多药耐药的鲍曼氏菌感染,由于其高敏感率和低毒性。
    Resistance of Acinetobacter baumannii to multiple clinically important antimicrobials has increased to very high rates in Greece, rendering most of them obsolete. The aim of this study was to determine the molecular epidemiology and susceptibilities of A. baumannii isolates collected from different hospitals across Greece. Single-patient A. baumannii strains isolated from blood cultures (n = 271), from 19 hospitals, in a 6-month period (November 2020-April 2021) were subjected to minimum inhibitory concentration determination and molecular testing for carbapenemase, 16S rRNA methyltransferase and mcr gene detection and epidemiological evaluation. 98.9% of all isolates produced carbapenemase OXA-23. The vast majority (91.8%) of OXA-23 producers harbored the armA and were assigned mainly (94.3%) to sequence group G1, corresponding to IC II. Apramycin (EBL-1003) was the most active agent inhibiting 100% of the isolates at ≤16 mg/L, followed by cefiderocol which was active against at least 86% of them. Minocycline, colistin and ampicillin-sulbactam exhibited only sparse activity (S <19%), while eravacycline was 8- and 2-fold more active than minocycline and tigecycline respectively, by comparison of their MIC50/90 values. OXA-23-ArmA producing A. baumannii of international clone II appears to be the prevailing epidemiological type of this organism in Greece. Cefiderocol could provide a useful alternative for difficult to treat Gram-negative infections, while apramycin (EBL-1003), the structurally unique aminoglycoside currently in clinical development, may represent a highly promising agent against multi-drug resistant A. baumanni infections, due to its high susceptibility rates and low toxicity.
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  • 文章类型: Journal Article
    遗传多样性的详细分析,抗原变异性,蛋白质定位和免疫反应对于新型疟疾疫苗候选物的优先排序至关重要。确定提供广泛保护所需的最合适的抗原变体的综合方法具有挑战性,因此很少进行。
    这里,我们对PF3D7_1136200进行了表征,根据对其序列的分析,我们将其命名为富含天冬酰胺的孢子抗原(ARMA),定位和免疫原性。我们在布基纳法索(N=228)的独立前瞻性队列研究中分析了针对ARMA常见变体的IgG和IgM反应,肯尼亚(N=252)和马里(N=195)使用定制微阵列,Div-KILCHIP.
    我们在非洲和亚洲的寄生虫之间发现了明显的种群结构。非洲分离株共有34种常见单倍型,包括优势对,尽管总体选择压力是方向性的(Tajima\sD=-2.57;Fu和Li\sF=-9.69;P<0.02)。ARMA位于裂殖子表面,IgG抗体诱导Fc介导的自然杀伤细胞脱颗粒,并在体外强烈抑制寄生虫的生长。我们发现了深刻的血清学多样性,但IgG和IgM应答高度相关,分层聚类分析仅鉴定出三种主要血清群.保护性IgG和IgM抗体似乎靶向跨变体的交叉反应性表位和不同表位。然而,针对选定变异体的IgG和IgM抗体组合与针对疟疾临床发作的完全保护相关.
    我们的系统策略利用基因组数据来推断少数抗原变体,这些抗原变体具有最强的诱导广泛保护的潜力,并且可能广泛适用于有效疫苗仍然难以捉摸的其他复杂病原体。
    Detailed analyses of genetic diversity, antigenic variability, protein localization and immunological responses are vital for the prioritization of novel malaria vaccine candidates. Comprehensive approaches to determine the most appropriate antigen variants needed to provide broad protection are challenging and consequently rarely undertaken.
    Here, we characterized PF3D7_1136200, which we named Asparagine-Rich Merozoite Antigen (ARMA) based on the analysis of its sequence, localization and immunogenicity. We analyzed IgG and IgM responses against the common variants of ARMA in independent prospective cohort studies in Burkina Faso (N = 228), Kenya (N = 252) and Mali (N = 195) using a custom microarray, Div-KILCHIP.
    We found a marked population structure between parasites from Africa and Asia. African isolates shared 34 common haplotypes, including a dominant pair although the overall selection pressure was directional (Tajima\'s D = -2.57; Fu and Li\'s F = -9.69; P < 0.02). ARMA was localized to the merozoite surface, IgG antibodies induced Fc-mediated degranulation of natural killer cells and strongly inhibited parasite growth in vitro. We found profound serological diversity, but IgG and IgM responses were highly correlated and a hierarchical clustering analysis identified only three major serogroups. Protective IgG and IgM antibodies appeared to target both cross-reactive and distinct epitopes across variants. However, combinations of IgG and IgM antibodies against selected variants were associated with complete protection against clinical episodes of malaria.
    Our systematic strategy exploits genomic data to deduce the handful of antigen variants with the strongest potential to induce broad protection and may be broadly applicable to other complex pathogens for which effective vaccines remain elusive.
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  • 文章类型: Journal Article
    阻塞的河流失去了流动循环的自然特征,并受到水力发电厂的能源需求的控制。随着能源生产厂与巴西中央车站的连接,由于该国不同地区的需求会影响水流,因此情况更加恶化。使用Tucuruí大坝50年的下游流量数据,我们测试了水流的变化是否已经改变。我们观察到水流量的年度变化和大坝下游的极端洪水事件的增加,表明大坝的运行加强了对水道的控制。该研究表明,在1997年Tucurui大坝与中央系统互连之后,大坝下游部分的水流变化增加。大坝的管理策略应考虑与国家电力需求相结合,因为遥远的需求可能会影响当地的环境。
    Dammed rivers lose its natural characteristics of the flow cycle and becomes controlled by the energy demands of the hydroelectric plants. With the connection of the energy-producing plants to a central station in Brazil the situation is aggravated since demands in different regions of the country affect the water flow. Using downstream flow data from the Tucuruí dam over a 50-year period, we tested whether the variation in water flow has changed. We observed an increase of the annual variation of the water flow and the extreme events of flooding at downstream of the dam, indicating the operation of the dam intensified the control of water passage. The study reveals an increase in the variation of water flow in the dam\'s downstream section following the interconnection of the Tucurui dam with the Central System in 1997. Management strategies for the dam should be considered integrated with the national electricity demand, since distant demands may affect the local environment in question.
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  • 文章类型: Journal Article
    在ST196和ST648的两个无关的大肠杆菌中检测到了一种新型的多药耐药性接合177,859bp的IncC质粒pJEF1-OXA-181,其中包含碳青霉烯酶编码blaOXA181和氨基糖苷抗性16SrRNA甲基转移酶编码armA基因,以及囊性纤维化患者的两个ST35肺炎克雷伯菌和痰菌分离株。arma基因位于抗菌素耐药岛ARI-A和blaOXA181基因内,在IS903和ISEcp1Δ之前,将其插入转移基因区域而不影响缀合能力。与其他相关IncC质粒的比较质粒分析显示blaOXA181的存在及其整合位点,因此对于这些类型的质粒是独一无二的。这项研究说明了混杂的多药抗性质粒获得抗生素抗性基因并在同一宿主的肠道中传播的潜力。重要性碳青霉烯酶和氨基糖苷抗性16SrRNA甲基化酶在多药抗性接合质粒上的共定位对公众健康构成严重威胁。这里,我们描述了囊性纤维化患者痰和肠道微生物群的不同肠杆菌分离株中携带blaOXA-181和armA的新型IncC质粒pJEF1-OXA-181以及其他几种抗菌药物耐药基因(ARGs).IncC质粒是共轭的,混杂的元素可以包含辅助抗菌素耐药性岛,使其成为ARGs传播的关键参与者。到目前为止,该质粒在IncC质粒中是唯一的,它含有blaOXA-181,该blaOXA-181整合在转移基因区域而不影响其接合能力。这项研究强调,新的质粒可能会通过单个患者中托管的不同物种引入医院。它进一步强调需要连续监测处于危险中的患者的多药耐药细菌,以避免此类质粒在医疗保健系统中的传播。
    A novel multidrug resistance conjugative 177,859-bp IncC plasmid pJEF1-OXA-181 coharboring the carbapenemase-coding blaOXA181 and the aminoglycoside resistance 16S rRNA methyltransferase-coding armA genes was detected in two unrelated Escherichia coli gut isolates of ST196 and ST648, as well as two ST35 Klebsiella pneumoniae gut and sputum isolates of a cystic fibrosis patient. The armA gene was located within the antimicrobial resistance island ARI-A and the blaOXA181 gene, which was preceded by IS903 and ISEcp1Δ was inserted within the transfer genes region without affecting conjugation ability. Comparative plasmid analysis with other related IncC plasmids showed the presence of blaOXA181, as well as its integration site, are thus far unique for these types of plasmids. This study illustrates the potential of a promiscuous multidrug resistance plasmid to acquire antibiotic resistance genes and to disseminate in the gut of the same host. IMPORTANCE Colocalization of carbapenemases and aminoglycoside resistance 16S rRNA methylases on a multidrug resistance conjugative plasmid poses a serious threat to public health. Here, we describe the novel IncC plasmid pJEF1-OXA-181 cocarrying blaOXA-181 and armA as well as several other antimicrobial resistance genes (ARGs) in different Enterobacterales isolates of the sputum and gut microbiota of a cystic fibrosis patient. IncC plasmids are conjugative, promiscuous elements which can incorporate accessory antimicrobial resistance islands making them key players in ARGs spread. This plasmid was thus far unique among IncC plasmids to contain a blaOXA-181 which was integrated in the transfer gene region without affecting its conjugation ability. This study highlights that new plasmids may be introduced into a hospital through different species hosted in one single patient. It further emphasizes the need of continuous surveillance of multidrug-resistant bacteria in patients at risk to avoid spread of such plasmids in the health care system.
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  • 文章类型: Journal Article
    碳价格及其相关成分的波动能够有效反映整体经济状况。本文探讨了碳价格的波动及其影响因素。首先,采用集合经验模态分解(EEMD)方法对8个试点项目的碳价序列进行多时间尺度分解。第二,根据八个试点项目的历史交易记录,本文构建了各种情景下的全国碳价。最后,根据八个试点市场每日交易数据集的平均值,全国碳价建设,并进行了短期预测。结果表明:(1)北京和湖北试点项目易受短期外部因素的影响,北京试点的内部市场机制对碳价格有很大影响;(2)在大多数情况下,全国物价波动,最高碳价接近70CNY/tCO2,最低碳价低于10CNY/tCO2;(3)中国碳价未来仍有充足的上涨空间。本文为我国碳价格的预测提供了理论依据和实践指导。
    The fluctuation of the carbon price and its related components can effectively reflect the overall economy. This paper explores the fluctuation of the carbon price and its influencing factors. First, the ensemble empirical mode decomposition (EEMD) method is used to decompose the carbon price series of eight pilot projects at multiple timescales. Second, according to the historical trading records in the eight pilot projects, this paper constructs a national carbon price under a variety of scenarios. Finally, based on the average of the eight pilot market daily trading datasets, the national carbon price is constructed, and a short-term prediction is made. The results show that: (1) the pilot projects in Beijing and Hubei are susceptible to short-term external factors, and Beijing\'s pilot internal market mechanism has a large impact on the carbon price; (2) in most scenarios, the national price fluctuates, with the highest carbon price approaching 70 CNY/tCO2 and the lowest falling below 10 CNY/tCO2; and (3) China\'s carbon price is still has ample room to rise in the future. This paper provides a theoretical basis and practical guidance for the prediction of carbon prices in China.
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  • 文章类型: Journal Article
    在本文中,我们提出了一种新颖的混合模型,该模型通过使用模糊熵和极限学习机(ELM)方法来扩展涉及集成经验模式分解(EEMD)的先验工作。我们通过将其应用于以混沌和复杂性为特征的碳期货价格预测来证明该三阶段模型。首先,我们采用EEMD方法将碳期货价格分解为几个内在模式函数(IMFs)和一个残差。第二,利用模糊熵和K-均值聚类方法对IMFs和残差进行重构,得到3个重构分量,特别是高频系列,低频系列,和趋势系列。第三,ARMA模型是为固定的高频和低频系列实现的,而极限学习机(ELM)模型用于非平稳趋势序列。最后,所有的成分预测被汇总以形成每个模型的碳价的最终预测。实证结果表明,在相同的预测框架下,与传统的细粗重构算法相比,本文提出的重构算法可以带来40%以上的预测精度提升。本文提出的混合预测模型也很好地抓住了价格变动的方向,具有强大而强大的预测能力,显著优于单一预测模型和其他混合预测模型。
    In this paper, we propose a novel hybrid model that extends prior work involving ensemble empirical mode decomposition (EEMD) by using fuzzy entropy and extreme learning machine (ELM) methods. We demonstrate this 3-stage model by applying it to forecast carbon futures prices which are characterized by chaos and complexity. First, we employ the EEMD method to decompose carbon futures prices into a couple of intrinsic mode functions (IMFs) and one residue. Second, the fuzzy entropy and K-means clustering methods are used to reconstruct the IMFs and the residue to obtain three reconstructed components, specifically a high frequency series, a low frequency series, and a trend series. Third, the ARMA model is implemented for the stationary high and low frequency series, while the extreme learning machine (ELM) model is utilized for the non-stationary trend series. Finally, all the component forecasts are aggregated to form final forecasts of the carbon price for each model. The empirical results show that the proposed reconstruction algorithm can bring more than 40% improvement in prediction accuracy compared to the traditional fine-to-coarse reconstruction algorithm under the same forecasting framework. The hybrid forecasting model proposed in this paper also well captures the direction of the price changes, with strong and robust forecasting ability, which is significantly better than the single forecasting models and the other hybrid forecasting models.
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