分类： 其他 分类： 其他 提交时间： 2024-04-25
摘要： The Australia Telescope Large Area Survey (ATLAS) and the VLA survey in the XMM-LSS/VIDEO deep field provide deep ($\approx 15$ ${\mu}$Jybeam$^{-1}$) and high-resolution ($\approx$ 4.5--8 arcsec) radio coverage of the three XMM-SERVS fields (W-CDF-S, ELAIS-S1, and XMM-LSS). These data cover a total sky area of 11.3 deg$^2$ and contain $\approx 11000$ radio components. Furthermore, about 3~deg$^2$ of the XMM-LSS field also has deeper MIGHTEE data that achieve a median RMS of 5.6 ${\mu}$Jy beam$^{-1}$ and detect more than 20000 radio sources. We analyze all these radio data and find source counterparts at other wavebands utilizing deep optical and IR surveys. The nature of these radio sources is studied using radio-band properties (spectral slope and morphology), and the IR-radio correlation. %and spectral energy distribution. Radio AGNs are selected and compared with those selected using other methods (e.g. X-ray). We found 1656 new AGNs that were not selected using X-ray and/or MIR methods. We constrain the FIR-to-UV SEDs of radio AGNs using {\sc cigale} and investigate the dependence of radio AGN fraction upon galaxy stellar mass and star-formation rate.
分类： 其他 分类： 其他 提交时间： 2024-04-25
摘要： We present X-ray spectral and long-term variability analyses of an unbiased sample of 361 optically selected radio-loud quasars (RLQs) utilizing sensitive serendipitous X-ray data from the Chandra and XMM-Newton archives. The spectral and temporal properties of RLQs are compared with those of radio-quiet quasars (RQQs) matched in $L_\mathrm{2500A}$ and $z$. The median power-law photon index ($\Gamma$) of RLQs is $1.84^{+0.01}_{-0.01}$, which is close to that of matched RQQs ($1.90^{+0.02}_{-0.01}$). No significant correlations between $\Gamma$ and radio-loudness, $L_\mathrm{x}/L_\mathrm{x,rqq}$ (the X-ray luminosity over that expected from the $L_\mathrm{x}$-$L_\mathrm{uv}$ relation for RQQs), redshift, or Eddington ratio are found for our RLQs. The stacked X-ray spectra of our RLQs show strong iron-line emission and a possible Compton-reflection hump. The intrinsic X-ray variability amplitude is $\approx40$% for RLQs on timescales of months-to-years in the rest frame, which is somewhat smaller than for the matched RQQs ($\approx60$%) on similar timescales, perhaps due to the larger black-hole masses and lower Eddington ratios in our RLQ sample. The X-ray spectral and variability results for our RLQs generally support the idea that the X-ray emission of typical RLQs is dominated by the disk/corona, as is also indicated by a recent luminosity correlation study.
分类： 其他 分类： 其他 提交时间： 2024-04-25
摘要： Radio-loud quasars (RLQs) are known to produce excess X-ray emission, compared to radio-quiet quasars (RQQs) of the same luminosity, commonly attributed to jet-related emission. Recently, we found that the HeII EW and $\alpha_{\rm{ox}}$ in RQQs are strongly correlated, which suggests that their extreme-ultraviolet (EUV) and X-ray emission mechanisms are tightly related. Using 48 RLQs, we show that steep-spectrum radio quasars (SSRQs) and low radio-luminosity ($L_{\rm R}$) flat-spectrum radio quasars (FSRQs) follow the $\alpha_{\rm ox}$--HeII EW relation of RQQs. This suggests that the X-ray and EUV emission mechanisms in these types of RLQs is the same as in RQQs, and is not jet related. High-$L_{\rm R}$ FSRQs show excess X-ray emission given their HeII EW by a factor of $\approx$ 3.5, which suggests that only in this type of RLQ is the X-ray production likely jet related.
分类： 其他 分类： 其他 提交时间： 2024-04-25
摘要： Radio-loud quasars (RLQs) are more X-ray luminous than predicted by the X-ray-optical/UV relation (i.e. $L_\mathrm{x}\propto L_\mathrm{uv}^\gamma$) for radio-quiet quasars (RQQs). The excess X-ray emission depends on the radio-loudness parameter ($R$) and radio spectral slope ($\alpha_\mathrm{r}$). We construct a uniform sample of 729 optically selected RLQs with high fractions of X-ray detections and $\alpha_\mathrm{r}$ measurements.We find that steep-spectrum radio quasars (SSRQs; $\alpha_\mathrm{r}\le-0.5$) follow a quantitatively similar $L_\mathrm{x}\propto L_\mathrm{uv}^\gamma$ relation as that for RQQs, suggesting a common coronal origin for the X-ray emission of both SSRQs and RQQs. However, the corresponding intercept of SSRQs is larger than that for RQQs and increases with $R$, suggesting a connection between the radio jets and the configuration of the accretion flow. Flat-spectrum radio quasars (FSRQs; $\alpha_\mathrm{r}>-0.5$) are generally more X-ray luminous than SSRQs at given $L_\mathrm{uv}$ and $R$, likely involving more physical processes. The emergent picture is different from that commonly assumed where the excess X-ray emission of RLQs is attributed to the jets. We thus perform model selection to comparecritically these different interpretations, which prefers the coronal scenario with a corona-jet connection. A distinct jet component is likely important for only a small portion of FSRQs.The corona-jet, disk-corona, and disk-jet connections of RLQs are likely driven by independent physical processes. Furthermore, the corona-jet connection implies that small-scale processesin the vicinity of SMBHs, probably associated with the magnetic flux/topology instead of black-hole spin, are controlling the radio-loudness of quasars.
分类： 其他 提交时间： 2024-04-25
摘要： We have investigated the jet-linked \mbox{X-ray} emission from highly radio-loud quasars (HRLQs; $\log R>2.5$) at high redshift. We studied the X-ray properties of 15 HRLQs at $z>4$, using new {\it Chandra} observations for six objects and archival {\it XMM-Newton} and {\it Swift} observations for the other nine. We focused on testing the apparent enhancement of jet-linked \mbox{X-ray} emission from HRLQs at $z>4$. Utilizing an enlarged (24 objects) optically flux-limited sample with complete X-ray coverage, we confirmed that HRLQs at $z>4$ have enhanced X-ray emission relative to that of HRLQs at $z\approx$ 1--2 with matched UV/optical and radio luminosity, at a \mbox{4.0--4.6}~$\sigma$ level; the X-ray enhancements are confirmed considering both two-point spectral indices and inspection of broad-band spectral energy distributions. The typical factor of enhancement is revised to $1.9^{+0.5}_{-0.4}$, which is smaller than but consistent with previous results. A fractional IC/CMB model can still explain our results at high redshift, which puts tighter constraints on the fraction of IC/CMB X-rays at lower redshifts, assuming the physical properties of quasar jets do not have a strong redshift dependence. A dominant IC/CMB model is inconsistent with our data.
分类： 其他 提交时间： 2024-04-25
摘要： Rapid flares from blazars in very high energy (VHE) $\gamma$-rays challenge the common understanding of jets of active galactic nuclei (AGNs). The same population of ultra-relativistic electrons is often thought to be responsible for both X-ray and VHE emission. We thus systematically searched for X-ray flares at sub-hour timescales of TeV blazars in the entire Rossi X-ray Timing Explorer archival database. We found rapid flares from PKS 2005-489 and S5 0716+714, and a candidate rapid flare from 1ES 1101-232. In particular, the characteristic rise timescale of PKS 2005-489 is less than half a minute, which, to our knowledge, is the shortest among known AGN flares at any wavelengths. The timescales of these rapid flares indicate that the size of the central supermassive black hole is not a hard lower limit on the physical size of the emission region of the flare. PKS 2005-489 shows possible hard lags in its flare, which could be attributed to particle acceleration (injection), its flaring component has the hardest spectrum when it first appears. For all flares, the flaring components show similar hard spectra with $\Gamma=1.7-1.9$, and we estimate the magnetic field strength $B\sim$ 0.1--1.0 G by assuming synchrotron cooling. These flares could be caused by inhomogeneity of the jets. Models that can only produce rapid $\gamma$-ray flares but little synchrotron activity are less favorable.
分类： 其他 分类： 其他 分类： 其他 提交时间： 2024-04-25
摘要： Fluxes emitted at different wavebands from active galactic nuclei (AGNs) fluctuate at both long and short timescales. The variation can typically be characterized by a broadband power spectrum, which exhibits a red-noise process at high frequencies. The standard method of estimating power spectral density (PSD) of AGN variability is easily affected by systematic biases such as red-noise leakage and aliasing, in particular, when the observation spans a relatively short period and is gapped. Focusing on the high-frequency PSD that is strongly distorted due to red-noise leakage and usually not significantly affected by aliasing, we develop a novel and observable normalized leakage spectrum (NLS), which describes sensitively the effects of leaked red-noise power on the PSD at different temporal frequencies. Using Monte Carlo simulations, we demonstrate how an AGN underlying PSD sensitively determines the NLS when there is severe red-noise leakage and thereby how the NLS can be used to effectively constrain the underlying PSD.
分类： 其他 提交时间： 2024-04-25
摘要： 观察耳穴贴压联合耳尖放血治疗一例外感咳嗽病患者的疗效。选取1例外感咳嗽患者，通过耳穴贴压对针对性穴位进行按摩，结合耳尖放血的治疗手法，达到有效改善平衡阴阳、调整脏腑、疏通经络、扶正祛邪、活血止痛，有效缓解患者咳嗽咳痰症状，从而缓解病情，促进康复，临床效果良好，无明显不良反应。
摘要： 關於皎然生年的問題向來疑義不大，學者賈晉華《皎然年譜》裡將《贈李中丞洪》“安知七十年，一朝值宗伯”的表述解讀為皎然自稱時年七十，而該詩的寫作時間可考證為貞元五年，因此皎然生年被確定為公元720年。此外，傅璇琮主編《唐才子傳校箋》的皎然上人傳校注部分、李壯鷹所著《詩式校注》的前言部分也均以此句理解為皎然自稱七十歲而得見李洪，這一問題似乎就此解決，而皎然生年為公元720年也成為定說。不過近來學者張培鋒撰文指出，諸學者將“安知七十年，一朝值宗伯”一聯解釋為皎然自陳之言，實屬誤解詩意，是未能通篇考察全詩的緣故。張培鋒以理校的方式，根據文意的解讀將《贈李中丞洪》一詩分為兩部分，前部分自“深沈閫外略”至“君子情何如”是皎然贈詩，後部分自“伊昔避事心”至“胡爲自塵汚”是李洪的答詩，因此“安知七十年”一聯並非源於皎然的自陳，而是出自李洪的答詩，因此不能作為判斷皎然生年的依據。該說法是細讀全詩所得，甚有見地，不過論證過程稍有差誤，且根據《文苑英華》對《贈李中丞洪》一詩收錄的面貌，可以為張氏的理校補充相應的文本證據，姑且成文。
摘要： 贺绿汀精神包括三层内涵，即坚定理想、崇尚真理的忠诚精神，融合中西、革新音乐的求索精神，刚强不屈、敢于斗争的硬骨头精神。居其宏批评歌剧《贺绿汀》的文章《硬骨头音乐家与歌剧艺术的粗鄙遇合》错解了贺绿汀精神，体现为笼统地把敢言特征视为硬骨头精神，把贺绿汀精神建筑在“吕贺之争”基础之上，把贺绿汀精神庸俗化用作批评工具。此文论证过程中存在苛求作品选材、窄化歌剧思维、混淆两种真实、歪析人物唱词、论述自相矛盾、夸大批评主体、误置批评对象等七种偏差，整体上实为谬见。歌剧《贺绿汀》展现了贺绿汀精神的内涵魅力，允称佳作，大有功绩。
分类： 其他 提交时间： 2024-04-07
摘要： 本文总结1例面肌痉挛患者行火龙罐综合灸治疗的效果观察及护理经验。基于中医辨证施护理论基础上，给予火龙罐综合灸治疗并进行动态观察，同时配合情志护理、生活起居护理等常规护理措施，有效改善了患者的临床症状，缓解患者焦虑，提高了患者的舒适度及生活质量。
分类： 其他 >> 综合 提交时间： 2024-03-28 合作期刊: 《文献与数据学报》
摘要： ［目的 / 意义］指出《大规模现代汉语分词语料库构建及应用》一书的主要价值与贡献，旨在为中文语料库的构建提供借鉴，以促进大语言模型下中文自然语言处理的快速发展。［方法 / 过程］从宏观和微观的视角，对新时代人民日报分词语料库的构建和语料库相关研究综述进行了基于语料库计量语言学的分析，并对深度学习下的人民日报知识组织等内容进行了评介。［结果 / 结论］《大规模现代汉语分词语料库构建及应用》一书基于新时代人民日报分词语料库构建及应用进行研究，不仅传承了北京大学人民日报语料库的体系和理念，而且在一定程度上为解决领域化自然语言处理的任务提供了相应的方案。
分类： 管理学 >> 管理学其他学科 分类： 其他 >> 综合 分类： 医学、药学 >> 医学、药学其他学科 提交时间： 2024-03-28 合作期刊: 《文献与数据学报》
摘要： ［目的 / 意义］在线健康社区是人们获取健康信息的重要途径，研究在线健康社区用户用药咨询需求，有助于在线健康社区药品服务优化及可持续发展。［方法 / 过程］以 39 健康网为例，首先，利用 Python 编码爬取肠胃用药类药品的 59 048 条用药咨询评论，并进行预处理；其次，使用 TF-IDF、TextRank、LDA 主题模型等文本挖掘方法对实验数据进行主题关键词挖掘，并进行关键词共现网络分析；最后，综合分析在线健康社区用户用药咨询需求的主题特征，并提出优化建议。［结果 / 结论］研究结果发现在线健康社区用户主要关注药品治疗效果、服用方式、不良反应、药品区别以及孕妇等特殊人群在用药时的注意事项等。本研究一方面为药品厂商调整优化药品说明书内容提供了理论依据，另一方面为在线健康社区优化药品说明书内容布局以及建立或完善药品科普服务指引了方向。
分类： 其他 >> 综合 提交时间： 2024-03-28 合作期刊: 《文献与数据学报》
摘要： ［目的 / 意义］推动政府数据共享开放是促进数字经济发展、增强社会治理效能的基本要义。［方法 / 过程］基于需求导向、动力支撑与数字赋能三维框架，以中国 31 个省份（未含香港、澳门、台湾地区）为研究案例，运用模糊集定性比较分析方法（fsQCA）对政府数据开放的影响因素进行组态分析。［结果 / 结论］单一因素并不能够驱动高政府数据开放水平的产生，而是以组态形式发挥作用；需求导向、动力支撑与数字赋能维度各要素交互作用形成驱动政府数据开放的 5 种组态路径；根据主导力量的不同，可将组态路径概括为三种类型，即需求导向型、数字赋能型和混合联动型。为此，要识别驱动地方政府数据开放的关键力量，因地制宜制定最优政策工具集，推进政府数据有序开放，进一步释放数据活力和效益。
分类： 其他 >> 综合 提交时间： 2024-03-28 合作期刊: 《文献与数据学报》
摘要： ［目的 / 意义］标准数字化能够深度挖掘标准潜在知识，并释放标准潜在价值。标准数字化治理战略直接关乎我国数字经济发展和国际竞争力的提升。［方法 / 过程］基于全球标准数字化变革趋势，从新技术、发展政策、发展格局、治理理念四方面进行研究。［结果 / 结论］研究结果表明：（1）标准数字化治理需把握四个机遇，一是标准数字化新技术促进标准链产业链全链条发展，二是标准化发展政策鼓励引导标准数字化发展，三是传统标准化发展格局产生变革，四是标准数据治理理念发生改变。（2）标准数字化治理正面临三个挑战，一是基本理论、关键技术、实施路径和应用场景尚未形成完整体系，二是成熟产品和优秀试点案例较少，三是制度体系和管理机制有待健全和完善。（3）标准数字化治理需考虑四项对策，一是大力发展基础概念体系和基础共性关键技术，二是强化相关政策保障，三是推动相关理论与各类业务场景融合和创新应用，四是提前谋划未来国际市场。
分类： 其他 >> 综合 提交时间： 2024-03-28 合作期刊: 《文献与数据学报》
摘要： ［目的 / 意义］皮书评价在皮书发展过程中发挥着关键的引领作用，是皮书分级资助、评奖及淘汰的重要衡量依据。科学合理的皮书影响力评价指标体系能够为皮书评价工作的有序进行提供保障，对于保证评价结果公正客观、推动皮书评价发挥学术引领作用具有重要意义。［方法 / 过程］采用文献调查法、问卷调查法及层次分析法，综合考虑各项原则，设置决策影响力、学术影响力、使用影响力和社会影响力 4 个一级指标，下设 10 个二级指标和 16 个三级指标，确定指标权重，选择 51 本第十二届“优秀皮书奖”皮书进行实证研究。［结果 / 结论］ 本文实证研究结果与实际获奖情况存在关联，构建的皮书影响力评价指标体系具有一定的有效性和合理性，提出了优化皮书评价的建议。
分类： 图书馆学、情报学 >> 各类型图书馆 分类： 其他 >> 综合 提交时间： 2024-03-28 合作期刊: 《文献与数据学报》
摘要： ［目的 / 意义］学术论文评价在整个科学评价系统中具有较强的基础性和辐射性作用。构建能够反映学术论文长期学术影响的测度指标，是完善学术论文评价体系的重要一环。［方法 / 过程］本文研究和构建了能够综合考虑直接引用和间接引用的引用链关系、兼顾学术成果持续性知识贡献水平的论文学术影响力评价方法（简称 MGR-KI 方法），并以电磁超材料领域的 2070 篇论文涉及的 7652 组引用关系和 14 074 058 条引文链路为数据源展开实证研究，验证了本文所构建方法的可行性和有效性。［结果 / 结论］本文构建的基于 MGR-KI 的学术影响力评价方法兼顾了不同被引类型特征，同时相较于被引频次和被引 h 指数的学术论文影响力评价结果，该方法表现出更强的区分度，更利于开展相同被引频次下不同论文的精细化对比与评价。基于特征维度与语义维度的文本相似度计算方法的不同会对结果造成显著影响，后续需要展开更细粒度上的知识遗传关系挖掘和遗传强度计算方法研究，实现更加精确的测度与评价。
分类： 其他 >> 综合 提交时间： 2024-03-13 合作期刊: 《干旱区科学》
摘要： Improving cultivated land use eco-efficiency (CLUE) can effectively promote agricultural sustainability, particularly in developing countries where CLUE is generally low. This study used provincial-level data from China to evaluate the spatiotemporal evolution of CLUE from 2000 to 2020 and identified the influencing factors of CLUE by using a panel Tobit model. In addition, given the undesirable outputs of agricultural production, we incorporated carbon emissions and nonpoint source pollution into the global benchmark-undesirable output-super efficiency-slacks-based measure (GB-US-SBM) model, which combines global benchmark technology, undesirable output, super efficiency, and slacks-based measure. The results indicated that there was an upward trend in CLUE in China from 2000 to 2020, with an increase rate of 2.62%. The temporal evolution of CLUE in China could be classified into three distinct stages: a period of fluctuating decrease (2000–2007), a phase of gradual increase (2008–2014), and a period of rapid growth (2015–2020). The major grain-producing areas (MPAs) had a lower CLUE than their counterparts, namely, non-major grain-production areas (non-MPAs). The spatial agglomeration effect followed a northeast-southwest strip distribution; and the movement path of barycentre revealed a "P" shape, with Luoyang City, Henan Province, as the centre. In terms of influencing factors of CLUE, investment in science and technology played the most vital role in improving CLUE, while irrigation index had the most negative effect. It should be noted that these two influencing factors had different impacts on MPAs and non-MPAs. Therefore, relevant departments should formulate policies to enhance the level of science and technology, improve irrigation condition, and promote sustainable utilization of cultivated land.
分类： 其他 分类： 其他 提交时间： 2024-03-11
摘要： 目的 通过随机对照试验评估中西医结合护理路径对呆病患者效果。方法 选取90名符合入选标准的患者，随机分为试验组（接受中西医结合护理）和对照组（接受常规护理）。在基线、干预第四周和出院后第四周测量MMSE、PSQI、ADL、MNA，进行组间比较。结果 ①MMSE：试验组在干预第四周和随访第四周明显提高（P＜0.05），且显著优于对照组（P＜0.05）。②PSQI：试验组在干预第四周和随访第四周明显下降（P＜0.05），对照组在干预第四周也下降（P＜0.05），试验组明显更佳（P＜0.05）。③ADL：两组无显著差异（P＞0.05）。④MNA：干预第四周两组无显著差异（P＞0.05），试验组随访第四周明显改善（P＜0.05）。结论 中西医结合护理路径对呆病患者病情干预效果较常规护理明显更佳。
摘要： 本研究运用三水平元分析技术系统探讨童年创伤与网络成瘾的关系及其调节因素。对纳入的66项研究和152个效应量进行分析, 结果显示, 童年创伤与网络成瘾存在显著正相关(r = 0.227)。此外, 童年创伤与网络成瘾的关系受童年创伤类型、创伤程度、童年创伤的测量工具、性别比例、样本独生子女比例以及文化背景的调节, 但不受网络成瘾类型及测量工具、被试年龄、数据类型以及数据收集时间的调节。本研究系统比较了不同类型童年创伤与网络成瘾的关系, 厘清了童年创伤与网络成瘾关系的理论争议, 并为网络成瘾的预防和干预提供了参考依据。
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