分类： 材料科学 >> 材料科学（综合） 提交时间： 2024-05-27
摘要： Manufacturing hydrogels with identical electrochemical properties are typically riddled with unresolved inquiries and challenges. Here, we utilized ultra-light graphene flakes to trace the influence of convection phenomena during reactions on hydrogels’ formation and structural non-uniformity, elucidating its mechanisms. Furthermore, we confirmed that an external electric field induced the orientation of functional groups of hydrogels along the direction of this field, revealing the mechanism of its influence on the structural non-uniformity and electrochemical properties of hydrogels. Additionally, we discovered that ion diffusion was Stumbling-to-Fetters by the functional groups on the polymer chains within the hydrogel, unveiling this mechanism and developing the Virginia Creeper (VC) model for hydrogels. We demonstrated the scalability and application of the VC model. Furthermore, we proposed a molecular-ion diffusion and current decay equation to describe the electrochemical properties of hydrogels. As an application of the VC model, we developed a bionic cardiovascular system and proved its potential to seamlessly interface with living organisms and generate bio-like bioelectricity. Our findings provide novel insights into triboelectricity and guidance for producing hydrogels with identical electrochemical properties, and offer a new pathway for bioelectric generation and the design of new hydrogel devices.
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2024-05-27 合作期刊: 《中国全科医学》
摘要： 急性缺血性卒中（AIS）具有高致残率、高致死率及高复发率等特点，给患者及社会造成沉重的负担。随着大数据时代的到来，预测模型在患者的诊治决策、预后管理以及卫生资源配置等方面的应用越来越多，其价值也愈发重要。机器学习方法是预测 AIS 患者预后的重要方法之一，且已广泛应用。本文以机器学习方法为重点，就AIS预后预测研究的最新进展予以综述，并提出机器学习预测模型目前所面临的问题与挑战，为 AIS 患者预后结局早期评估与预测在方法上提供新的思路和参考。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2024-05-27 合作期刊: 《中国全科医学》
摘要： 背景既往研究发现臂间血压差（IAD）和轻度认知功能障碍（MCI）均与心血管危险因素密切相关，但IAD与MCI之间是否存在关联尚不明确。目的 探讨农村老年人IAD与MCI的关系，为明晰老年人认知功能下降的机制提供科学依据。方法 于2019年7—8月采用多阶段整群抽样方法抽取贵州省2个县（区）5个乡镇的60岁及以上农村老年人进行问卷调查、一般体格检查、认知功能检查及双臂血压测量。采用简易精神状态评价量表（MMSE）评估认知功能，采用日常生活活动量表（ADL）评估日常生活功能状况。采用Spearman秩相关分析及二分类Logistic回归分析探究老年人IAD与MCI的关联性。结果 本次调查共发放问卷1795份，排除问卷信息不完整、未进行血压测量、未进行血液检查对象，最终纳入1088名参与者的数据进行研究。1088名农村老年人中，共检出MCI患者138例（12.68%），臂间收缩压差（sIAD）≥10mmHg者99例（9.10%），臂间舒张压差（dIAD）≥10mmHg者80例（7.35%）。与IAD<10mmHg人群相比，IAD≥10mmHg人群的MCI患病率更高，MMSE总分、定向力、语言能力和延时回忆力得分较低（P<0.05）。相关性分析结果显示，sIAD与MMSE总分（rs=-0.094）、定向力评分（rs=-0.082）、语言能力评分（rs=-0.065）和延迟回忆力评分（rs=-0.104）呈负相关（P<0.05）；dIAD与MMSE总分（rs=-0.080）、定向力评分（rs=-0.094）和注意计算力评分（rs=-0.063）呈负相关（P<0.05）。多因素Logistic回归分析显示，sIAD每增加1mmHg，MCI发生风险增加8.80%（OR=1.088，95%CI=1.046~1.131；P<0.001）；sIAD≥10mmHg（OR=2.169，95%CI=1.262~3.728；P<0.05）和dIAD≥10mmHg（OR=1.926，95%CI=1.047~3.542；P<0.05）是老年人发生MCI的影响因素。结论 农村老年人MCI患病率为12.68%，其IAD升高与MCI发生风险增加相关，IAD≥10mmHg人群MCI患病风险高于IAD<10mmHg人群。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2024-05-27 合作期刊: 《中国全科医学》
摘要： 背景尽管近年来肺栓塞继发肺梗死的病例不断见诸报道，但该病的误诊仍较普遍，其中最常被误诊为肺炎。尤其是存在中高危风险患者，延迟诊断、未能及时接受治疗将会影响患者的预后。目的 总结中高危肺栓塞继发肺梗死误诊为肺炎患者的临床特征，分析相关危险因素，并构建早期诊断模型。方法 回顾性收集中国科学技术大学附属第一医院2017—2023年确诊为中高危风险肺栓塞继发肺梗死的住院患者临床资料。分析患者误诊情况，根据诊断情况分为误诊组（曾误诊为肺炎离院回家）和对照组（门诊或急诊科首次就诊即正确诊断）。采用多因素二元Logistic回归分析探究中高危风险肺栓塞继发肺梗死误诊为肺炎的影响因素，绘制受试者工作特征曲线（ROC曲线）分析各指标对中高危风险肺栓塞继发肺梗死误诊为肺炎的预测价值，并采用Delong检验比较各ROC曲线下面积（AUC）。结果 共纳入患者101例，其中70例中高危肺栓塞继发肺梗死患者误诊为肺炎。2017—2023年中高危肺栓塞继发肺梗死患者误诊为肺炎的发生率呈下降趋势（依次为100.0%、83.3%、74.1%、71.4%、63.2%、66.7%、50.0%，P=0.010）。多因素二元Logistic回归分析结果显示，年龄≥60岁（OR=18.271，95%CI=4.373~76.339，P<0.001）、发热（OR=16.073，95%CI=3.510~73.786，P<0.001）、胸痛（OR=6.660，95%CI=1.571~28.233，P=0.010）和不伴有呼吸困难（OR=9.027，95%CI=2.049~30.249，P=0.003）是中高危风险肺栓塞继发肺梗死被误诊为肺炎的独立影响因素。多变量联合模型 =-6.624+0.095×年龄 +2.510× 发热 +2.683×不伴有呼吸困难，联合模型预测中高危风险肺栓塞继发肺梗死被误诊为肺炎的AUC为 0.880（95%CI=0.802~0.959），最佳截断值0.854，灵敏度0.871，特异性0.806。联合模型预测价值优于单因素指标如年龄（Z=2.771，P=0.006）、发热（Z=4.653，P<0.001）及不伴有呼吸困难（Z=4.014，P<0.001）。结论尽管2017—2023年中高危肺栓塞继发肺梗死患者误诊为肺炎的比例有所降低，但当老年肺栓塞患者出现发热、胸痛并且不伴有呼吸困难时，临床医生应注意肺梗死与肺炎的鉴别诊断。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2024-05-27 合作期刊: 《中国全科医学》
摘要： 背景以患者为中心的医疗质量改进中，将患者从医疗服务的接受者转变为合作者，将患者在医疗全流程中的体验和需求整合到医疗服务实践中，以提高医疗服务的有效性、效率和质量。然而，已被证明有效的以患者为中心的患者参与医疗质量改进策略在我国慢阻肺领域中如何实施尚有待探索。目的对国内外慢阻肺患者参与医疗质量改进策略的实施现状进行范围综述，旨在为构建适合我国环境的慢阻肺患者参与实施策略提供参考。方法 采用澳大利亚乔安娜布里格斯研究所的范围综述指南为方法学框架，计算机检索 PubMed、Embase、Cochrane Library、中国知网、万方数据知识服务平台和中华医学期刊全文数据库，检索时限为建库至 2022-11-29。采用主题分析法梳理慢阻肺患者参与的实施现状。结果 共纳入37篇文献。根据参与类别分为直接参与诊疗、参与组织层面的设计与管理、及参与临床研究三类。根据参与强度分为咨询、参与和合作领导三层。参与强度与类别交叉为 9 类参与行为矩阵。慢阻肺患者参与实施主要体现在5类8项行为：包括直接参与诊疗类的参与（患者对治疗计划提出意愿和偏好）；组织管理层面的咨询（调查了解患者治疗体验、组织患者讨论其关注的问题）和参与（参与医疗质量改进工具开发）；以及患者接受临床研究层面的咨询（倾听患者需求）和参与（对干预措施提出意愿和偏好、参与评估工具开发、参与研究设计与实施讨论）。调查患者治疗体验（10/37，27.03%）及收集患者对研究干预措施的意愿和偏好（10/37，27.03%）是实施较多的两类慢阻肺患者参与行为。结论患者参与医疗质量改进的行为措施较多，但在慢阻肺领域落地实践的尚较少，且极少见患者参与对临床结局及生活质量的改善评估，如何促进我国乃至全球慢阻肺患者参与医疗质量改进的实施仍有待进一步探索。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2024-05-27 合作期刊: 《中国全科医学》
摘要： 背景高血压是严重危害人群健康的常见慢性病，基层医生是高血压管理的主力军，而医源性治疗惰性在很大程度上影响了基层高血压控制的达标情况。目的 调查基层医生在高血压诊疗过程中的治疗惰性现状，并分析治疗惰性成因，为改善我国高血压控制率提供参照依据。方法 采用简单随机抽样法，于2023年7-8月向天津市32家基层卫生医疗机构的基层医生发放调查问卷，从高血压诊疗知识掌握程度以及“软理由”“高估治疗效果”“医保政策”这3个维度评价基层医生在高血压诊疗过程中的治疗惰性现状，采用二元Logistic回归分析探究治疗惰性的影响因素。结果 本研究共发放问卷407份，回收有效问卷386份，有效回收率97.96%。（1）基层医生高血压诊疗知识得分为6（0.5），得分率为61.19%（5.50/9.00）；高血压治疗惰性总得分为48（7.0）分，得分率为56.55%（45.24/80.00）。（2）“软理由”维度得分为26（4.8），得分率为51.97%（25.89/50.00）；“高估治疗效果”维度得分为10（2.0），得分率为65.42%（9.81/15.00）；“医保政策”维度得分为6（2.5），得分率为44.64%（6.96/15.00）。3个维度治疗惰性平均得分比较，“医保政策”维度得分相较于其他两组得分最低（P<0.05）。多因素分析显示，男性、涉农区域、高血压诊疗知识掌握程度较低以及每周接诊高血压患者人数≤10人的基层医生治疗惰性倾向更高（P<0.05）。结论 基层医生在高血压诊疗过程中普遍存在治疗惰性，高血压诊疗认知水平较低、“高估治疗效果”和“软理由”是导致基层医生在高血压诊疗过程中存在治疗惰性的主要因素。建议加强针对高血压治疗惰性的教育，开展多样化的诊疗知识及管理培训，同时推行临床信息化和人工智能决策系统，或可有效改善基层医生的高血压治疗惰性。
分类： 医学、药学 >> 预防医学与公共卫生学 提交时间： 2024-05-27 合作期刊: 《中国全科医学》
摘要： 背景糖尿病难以治愈且患病过程漫长，自我护理水平对糖尿病患者的疾病转归和健康结局至关重要，迫切需要理论指导下内容全面的糖尿病自我护理水平评估工具，以便及时掌握患者的自我护理情况，对应开展精准化护理。目的本研究旨在对糖尿病自我护理指数量表（SCODI）进行汉化，并检验中文版SCODI的信效度，为中国糖尿病患者提供自我护理的科学评估工具。方法采用Brislin翻译模式将原版SCODI翻译成中文，并进行文化调试。采用连续抽样法，选取 2022 年 12 月—2023 年 6 月南京医科大学第一附属医院和附属逸夫医院的 261 例糖尿病患者进行调查。使用研究者自行编制的一般资料调查表和汉化修订之后的中文版 SCODI 进行资料收集。采用探索性因子分析评估中文版SCODI的结构效度。采用 Cronbach's α系数、折半信度和组合信度描述量表的信度。本研究以生理指标糖化血红蛋白作为效标检验中文版 SCODI 的效标关联效度，采用 Spearman 秩相关分析探讨中文版 SCODI 得分与糖化血红蛋白水平的相关性。结果中文版 SCODI 包含 4 个分量表，共 40 个条目：自我护理维持得分为（75.94±13.15）分，自我护理监测得分为（70.65±18.71）分，自我护理管理得分为（69.16±18.24）分，自我护理信心得分为（85.41±13.63）分。自我护理维持分量表提取出 4 个因子（并发症筛查、运动锻炼、卫生保健、饮食服药），自我护理监测分量表提取出 2 个因子（身体监测、症状识别），自我护理管理分量表提取出 2 个因子（自主管理、咨询管理），自我护理自信分量表提取出 2 个因子（监测与管理信心、健康维持信心）。中文版 SCODI 总量表的 Cronbach's α 系数为 0.915，折半信度为 0.836，组合信度为 0.912，4 个分量表的 Cronbach's α 系数为 0.709~0.908。以生理指标糖化血红蛋白作为效标，各量表得分与糖化血红蛋白水平呈显著负相关（rs=-0.160、-0.300、-0.177、-0.192，P<0.001）。结论 基于慢性病自我护理中层理论开发的中文版 SCODI 具有良好的信度和效度，可用于评估中国糖尿病患者的自我护理水平。
分类： 管理学 >> 管理学其他学科 提交时间： 2024-05-26
摘要： 科学研究中对虚无假设检验（NHST: null hypothesis significance testing）以及p值的误用、滥用已经相当严重。NHST是Fisher显著性检验和N-P式假设检验的杂合体，但它又是如何杂合的，在计算步骤上如何体现？NHST和p值计算的逻辑缺陷在哪里？这些问题并没有详尽的、通俗的解答。明确地阐述Fisher显著性检验、N-P式假设检验、NHST的步骤并加以分析和比较，辅之以典型示例进行NHST和p值计算的逻辑缺陷分析，能够给未在统计学领域深耕的经验研究者提供一定的启发。
分类： 心理学 >> 应用心理学 分类： 心理学 >> 社会心理学 提交时间： 2024-05-26
摘要： 本研究探讨了产品属性和陈列秩序之间的匹配效应及其对消费者产品偏好的影响。基于联想学习理论，通过4个系列实验，发现产品属性和陈列秩序之间存在匹配关系，即产品的自然属性与无序陈列的关系更紧密，而产品的人工属性与有序陈列的关系更紧密，基于此提出了“自然-无序”与“人工-有序”的消费者朴素信念。这两种朴素信念进一步影响了消费者的产品偏好，当产品呈现自然属性(vs. 人工属性)时，消费者对无序陈列(vs. 有序陈列)下的产品产生更高的偏好，反之亦然，同时流畅性感知在其中起中介作用。进一步发现效价线索会在其中起到调节作用，效价线索的存在与否会改变消费者的产品偏好，即效价线索的出现显著提高了消费者对“自然-有序”和“人工-无序”的产品偏好及流畅性感知。这些结果说明了产品属性与陈列秩序之间存在密切联系，研究结论可为商家在商品陈列和广告营销的策略制定提供重要的实践启示。
分类： 生物学 >> 生物化学 提交时间： 2024-05-25
摘要： 药物成瘾是一种严重的慢性复发性脑病, 甲基苯丙胺成瘾病程复杂，难以治疗，造成严重的公共卫生负担。本研究对比分析了甲基苯丙胺成瘾急性戒断期患者（停止使用24小时以内）、甲基苯丙胺戒断康复期患者（停止使用3个月以上）、健康志愿者的尿液蛋白质组，甲基苯丙胺成瘾患者（甲基苯丙胺急性戒断期、甲基苯丙胺戒断康复期患者）的尿液蛋白质组与健康人之间显著不同，部分差异蛋白及其富集到的生物学功能，显示与成瘾或甲基苯丙胺的神经毒性有关，可能是药物成瘾的潜在的干预靶点；甲基苯丙胺戒断康复期患者仍难以恢复到正常人的水平，可能用于揭示甲基苯丙胺复吸率高的原因。本研究建立了一个从尿液蛋白质组学角度研究成瘾性药物的方法，证明了尿液蛋白质组能够相对系统、全面地反映甲基苯丙胺滥用对机体产生的影响，为临床成瘾性疾病的研究和实践提供线索。
分类： 生物学 >> 生物化学 提交时间： 2024-05-25
摘要： 服用复合营养素补充剂是一种常见的健康管理手段。还没有研究从尿液蛋白质组的角度探究复合营养素补充剂对健康人的整体影响。本研究对比分析了健康人服用复合营养素补充剂2周后、4周后与服用前的尿液蛋白质组，发现服用复合营养素补充剂2周后尿液蛋白质组的变化较为显著，差异蛋白及其富集到的通路与营养素补充可能相关，例如，促红细胞生成素受体（Erythropoietin receptor）（服用复合营养素两周后，9人中有4人发生从无到有的变化，9人的平均变化倍数（FC）达到450）。本研究的结果从尿液蛋白质组的角度提供关于复合营养素补充剂对健康的影响的新线索，有助于优化复合营养素补充剂的使用指南和建议，开发对于不同人群营养素补充的个性化策略。
分类： 生物学 >> 分子生物学 提交时间： 2024-05-24
摘要： Differential and even opposing functions of two major antioxidant transcription factors Nrf1 and Nrf2 (encoded by Nfe2l1 and Nfe2l2, respectively) are determined by distinctions in their tempospatial positioning, topological repartitioning, proteolytic processing, and biochemical modification, as well as in their shared evolutionary origin. As a matter of fact, the allelopathic potentials of Nrf1 and Nrf2 (both resembling two entangled ‘Yin-Yang’ quanta that comply with a dialectic law of the unity of opposites) are fulfilled to coordinately control redox physiological homeostasis so as to be maintained within the presetting thresholds. By putative exponential curves of redox stress and intrinsic anti-redox capability, there is inferable to exist a set point at approaching zero with the ‘Golden Mean’ for the healthy survival (i.e., dubbed the ‘zero theory’). A bulk of the hitherto accumulating evidence demonstrates that the set point of redox homeostasis is dictated selectively by multi-hierarchical threshold settings, in which the living fossil-like Nrf1 acts as a robust indispensable determinon, whereas Nrf2 serves as a versatile chameleon-like master regulon, in governing the redox homeodynamic ranges. This is attributable to the facts that Nrf2 has exerted certain ‘double-edged sword’ effects on life process, whereas Nrf1 executes its essential physiobiological functions, along with unique pathophysiological phenotypes, by integrating its ‘three-in-one’ roles elicited as a specific triplet of direct sensor, transducer and effector within multi-hierarchical stress responsive signaling to redox metabolism and target gene reprogramming. Here, we also critically reviewed redox regulation of physio-pathological functions from the eco-evo-devo perspectives, through those coding rules (redox code, stress-coping code, and topogenetic code). The evolving concepts on stress and redox stress were also further revisited by scientific principles of physics and chemistry, apart from two novel concepts of ‘oncoprotists’ and ‘reverse central dogma’ being introduced in this interdisciplinary and synthetic review.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
Xiaoyu Luo, Sheng Zheng, Zhibo Jiang, Zhiwei Chen, Yao Huang, Shuguang Zeng, Xiangyun Zeng, Rui Zhang, Chen Long, Guangrong Zhou et al.
Sheng Zheng
Zhibo Jiang
Zhiwei Chen
Yao Huang
Shuguang Zeng
Xiangyun Zeng
Rui Zhang
Chen Long
Guangrong Zhou
Jinbo Hu
摘要： In this study, we present a catalog of molecular clumps extracted from 13CO (J = 1 − 0) emission data of the Milky Way Imaging Scroll Painting (MWISP) project. The data covers the inner Milky Way within the longitude range 10° ≤ l ≤ 20° and the latitude strip of . The workflow for the extraction of clumps, namely Facet-SS-3D-Clump, consists of two parts: the identification of clump candidates and their verification. First, Facet-SS-3D-Clump employs FacetClumps to identify clump candidates. Subsequently, high-confidence clumps are obtained by cross-matching with the clumps detected by other algorithms, such as dendrogram. Second, these high-confidence clumps are used as prior knowledge to train a semi-supervised deep clustering approach, SS-3D-Clump, which is applied to verify clump candidates detected by FacetClumps, providing confidence levels for the molecular clumps. Finally, the catalog comprising 18,757 molecular clumps was obtained using Facet-SS-3D-Clump, and the catalog is 90% complete above 37 K km s−1. We observe a significant deviation of the mean Galactic latitude for clumps within ∣b∣ ≤ 2° from the midplane, with . We found that 82.3% of the dust clumps correspond to 13CO clumps by matching with Herschel infrared dust clumps. In the future, Facet-SS-3D-Clump will be applied to detect 13CO clumps in the entire MWISP data.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： Cassiopeia A (Cas A) is a well-known candidate for studying cosmic-ray acceleration, in which compact features of various scales have attracted much attention. Based on observations by the Very Large Array of Cas A at 6 cm and 21 cm, we measure the spectral index distribution of various scale components using the observation of the 1998 epoch. We decompose its total density image into nine scale components, and map the temperature spectral index distribution of each component, which ranges from −2.48 ± 0.01 to −2.91 ± 0.05. We find that the spectral indices increase from the small scale to large scale components. A damped post-shock magnetic field model with a strength larger than ∼200 μG and a damping length scale less than ∼10% of the remnant radius can account for the spectral index variation naturally.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： Temporary capture efficiency is studied in the framework of the circular restricted three-body problem in two steps. First, a non-uniform distribution of test particles around the secondary’s orbit is obtained by fully accounting the secondary’s gravitational influence. Second, the capture efficiency is computed based on the non-uniform distribution. Several factors influencing the result are discussed. By studying the capture efficiency in the circular restricted three-body problem of different mass ratios, a power-law relation between the capture efficiency (p) and the mass ratio (μ) is established, which is given by p ≈ 0.27 × μ0.53, within the range of 3.0035 ×10−6 ≤ μ ≤ 3.0034 × 10−5. Taking the Sun–Earth system as an example, the influence from the orbit eccentricity of the secondary on the non-uniform distribution and the capture efficiency is studied. Our studies find that the secondary’s orbit eccentricity has a negative influence on the capture efficiency.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： The distribution of the LSBGs is bimodal in the g − r color, indicating the two distinct populations of the blue (g − r 0.60) LSBGs. The blue LSBGs appear spiral, disk or irregular while the red LSBGs are spheroidal or elliptical and spatially clustered. This trend shows that the color has a strong correlation with galaxy morphology for LSBGs. In the spatial distribution, the blue LSBGs are more uniformly distributed while the red ones are highly clustered, indicating that red LSBGs preferentially populate a denser environment than the blue LSBGs. Besides, both populations have a consistent distribution of ellipticity (median ), half-light radius (median reff ∼ 4”) and Sérsic index (median n = 1), implying the dominance of the full sample by the round and disk galaxies. This sample has definitely extended the studies of LSBGs to a regime of lower surface brightness, fainter magnitude and broader other properties than the previously Sloan Digital Sky Survey-based samples.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： Open clusters (OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint (EC) for the members of cluster candidates using the homogeneity of color excess, compared to typical blind search codes, it is called Blind Search-Extra Constraint (BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams (CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess (or two-color) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large (e.g., ΔE(GBP − GRP) < 0.5 mag). It makes the CMDs of 15% clusters clearer (in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess constraint is more appropriate for clusters with small differential reddening, such as globular clusters or older OCs, and clusters that the distances of member stars cannot be determined accurately.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
Hao Li, Qing Zhao, Long Shao, Tao Liu, Chenzhou Cui and Yunfei Xu
Hao Li
Qing Zhao
Long Shao
Tao Liu
Chenzhou Cui
Yunfei Xu
摘要： Nowadays, astronomy has entered the era of Time-Domain Astronomy, and the study of the time-varying light curves of various types of objects is of great significance in revealing the physical properties and evolutionary history of celestial bodies. The Ground-based Wide Angle Cameras telescope, on which this paper is based, has observed more than 10 million light curves, and the detection of anomalies in the light curves can be used to rapidly detect transient rare phenomena such as microgravity lensing events from the massive data. However, the traditional statistically based anomaly detection methods cannot realize the fast processing of massive data. In this paper, we propose a Discrete Wavelet (DW)-Gate Recurrent Unit-Attention (GRU-Attention) light curve warning model. Wavelet transform has good effect on data noise reduction processing and feature extraction, which can provide richer and more stable input features for a neural network, and the neural network can provide more flexible and powerful output model for wavelet transform. Comparison experiments show an average improvement of 61% compared to the previous pure long-short-term memory unit (LSTM) model, and an average improvement of 53.5% compared to the previous GRU model. The efficiency and accuracy of anomaly detection in previous paper work are not good enough, the method proposed in this paper possesses higher efficiency and accuracy, which incorporates the Attention mechanism to find out the key parts of the light curve that determine the anomalies. These parts are assigned higher weights, and in the actual anomaly detection, the star is detected with 83.35% anomalies on average, and the DW-GRU-Attention model is compared with the DW-LSTM model, and the detection result f1 is improved by 5.75% on average, while having less training time, thus providing valuable information and guidance for astronomical observation and research.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： In this work, we consider a conventional test of gravitational wave (GW) propagation which is based on the phenomenological parameterized dispersion relation to describe potential departures from General Relativity (GR) along the propagation of GWs. But different from tests conventionally performed previously, we vary multiple deformation coefficients simultaneously and employ the principal component analysis (PCA) method to remedy the strong degeneracy among deformation coefficients and obtain informative posteriors. The dominant PCA components can be better measured and constrained, and thus are expected to be more sensitive to potential departures from the waveform model. Using this method we analyze ten selected events and get the result that the combined posteriors of the dominant PCA parameters are consistent with GR within 99.7% credible intervals. The standard deviation of the first dominant PCA parameter is three times smaller than that of the original dispersion parameter of the leading order. However, the multi-parameter test with PCA is more sensitive to not only potential deviations from GR but also systematic errors of waveform models. The difference in results obtained by using different waveform templates hints that the demands of waveform accuracy are higher to perform the multi-parameter test with PCA. Whereas, it cannot be strictly proven that the deviation is indeed and only induced by systematic errors. It requires more thorough research in the future to exclude other possible reasons in parameter estimation and data processing.
分类： 天文学 >> 天文学 提交时间： 2024-05-24 合作期刊: 《Research in Astronomy and Astrophysics》
摘要： Based on the collected multiwavelength data, namely in the radio (NVSS, FIRST, RATAN-600), IR (WISE), optical (Pan-STARRS), UV (GALEX), and X-ray (ROSAT, Swift-XRT) ranges, we have performed a cluster analysis for the blazars of the Roma-BZCAT catalog. Using two machine learning methods, namely a combination of PCA with k-means clustering and Kohonen’s self-organizing maps (SOMs), we have constructed an independent classification of the blazars (five classes) and compared the classes with the known Roma-BZCAT classification (FSRQs, BL Lacs, galaxy-dominated BL Lacs, and blazars of an uncertain type) as well as with the high synchrotron peaked (HSP) blazars from the 3HSP catalog and blazars from the TeVCat catalog. The obtained groups demonstrate concordance with the BL Lac/FSRQ classification along with a continuous character of the change in the properties. The group of HSP blazars stands out against the overall distribution. We examine the characteristics of the five groups and demonstrate distinctions in their spectral energy distribution shapes. The effectiveness of the clustering technique for objective analysis of multiparametric arrays of experimental data is demonstrated.
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