Segregation

隔离
  • 文章类型: Journal Article
    了解原子水平的晶体特性越来越成为创建具有可再现和均匀性质的量子位的固态平台的关键见解。这里,使用原子探针层析成像(APT)和飞行时间二次离子质谱法分析SiGe/28Si/SiGe异质结构中的同位素浓度深度分布,直至其各自的同位素浓度和深度分辨率极限。自旋回波移相时间T2echo=128μs$T_2^\\mathbf{echo}=128\\,\\umu\\mathrm{s}$和山谷能量分裂EVS大约200μeV$200\\,\\umu\\mathrm{e\\mathrm{V}}$已在此量子阱(QW)异质结构中观察到单自旋量子位,指向通过与晶体宿主核自旋的超精细相互作用或通过谷态之间的散射来抑制量子位退相干。在28SiQW中,携带核自旋的29Si的浓度为50±20ppm。APT的分辨率极限允许揭示QW的SiGe/28Si和28Si/SiGe界面均通过几个单层尺度的外延生长前沿偏析特征来成形。随后的热处理,代表异质结构在量子位器件处理期间经历的热预算,将顶部SiGe/28SiQW界面加宽约两个单层,而底部28Si/SiGe界面的宽度保持不变。使用包括SiGe合金无序的紧密结合模型,这些实验结果表明,稍微热加宽的顶部界面和在QW中0.3$0.3$%的最小Ge浓度的组合,由于隔离,对于观察到的大EVS=200μeV$E_\\mathrm{VS}=200\\,\\umu\\mathrm{e\\mathrm{V}}$。最小Ge添加量<1%,在薄QW中更有可能,因此,将支持高EVS,而不会影响连贯时间。同时,考虑到器件加工过程中的热处理以及晶体生长特性的发生,对于可重复量子位特性的设计似乎很重要。
    Understanding crystal characteristics down to the atomistic level increasingly emerges as a crucial insight for creating solid state platforms for qubits with reproducible and homogeneous properties. Here, isotope concentration depth profiles in a SiGe/28Si/SiGe heterostructure are analyzed with atom probe tomography (APT) and time-of-flight secondary-ion mass spectrometry down to their respective limits of isotope concentrations and depth resolution. Spin-echo dephasing times T 2 echo = 128 μ s $T_2^\\mathbf {echo}=128 \\,\\umu\\mathrm{s}$ and valley energy splittings EVS around 200 μ e V $200 \\,\\umu\\mathrm{e\\mathrm{V}}$ have been observed for single spin qubits in this quantum well (QW) heterostructure, pointing toward the suppression of qubit decoherence through hyperfine interaction with crystal host nuclear spins or via scattering between valley states. The concentration of nuclear spin-carrying 29Si is 50 ± 20ppm in the 28Si QW. The resolution limits of APT allow to uncover that both the SiGe/28Si and the 28Si/SiGe interfaces of the QW are shaped by epitaxial growth front segregation signatures on a few monolayer scale. A subsequent thermal treatment, representative of the thermal budget experienced by the heterostructure during qubit device processing, broadens the top SiGe/28Si QW interface by about two monolayers, while the width of the bottom 28Si/SiGe interface remains unchanged. Using a tight-binding model including SiGe alloy disorder, these experimental results suggest that the combination of the slightly thermally broadened top interface and of a minimal Ge concentration of 0.3 $0.3$ % in the QW, resulting from segregation, is instrumental for the observed large E VS = 200 μ e V $E_\\mathrm{VS}=200 \\,\\umu\\mathrm{e\\mathrm{V}}$ . Minimal Ge additions <1%, which get more likely in thin QWs, will hence support high EVS without compromising coherence times. At the same time, taking thermal treatments during device processing as well as the occurrence of crystal growth characteristics into account seems important for the design of reproducible qubit properties.
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  • 文章类型: Journal Article
    结构性种族主义已被确定为健康差距的根本原因。例如,种族,民族,和经济邻里隔离;集中贫困;社区撤资;社会文化背景影响肥胖和癌症差异。结构性种族主义的影响也很明显,例如在隔离社区内获得负担得起的健康食品和体育活动机会有限,导致肥胖和肥胖相关的癌症差异。本文描述并扩展了国家癌症研究所(NCI)举行的网络研讨会上提出的交叉主题:(1)结构因素如何,包括种族和族裔弱势社区内的邻里隔离和肥胖状况,影响美国的差异;(2)当前的研究挑战和解决这些挑战的最佳方法;(3)NCI的选定优先事项,旨在解决影响肥胖相关癌症差异的多层次和交叉因素.需要进一步的研究来了解住宅隔离和社区肥胖状况如何影响整个连续体的癌症预防和控制。使用健康框架的社会决定因素和以结构性种族主义为指导的社区参与方法,确定解决肥胖和癌症差异的最佳方法,将使研究人员能够超越个人层面的方法。
    Structural racism has been identified as a fundamental cause of health disparities. For example, racial, ethnic, and economic neighborhood segregation; concentrated poverty; community disinvestment; and sociocultural context influence obesity and cancer disparities. Effects of structural racism are also evident through neighborhood obesogenic conditions such as limited access to affordable and healthy foods and physical activity opportunities within segregated communities that contribute to obesity and obesity-related cancer disparities. This article describes and expands on cross-cutting themes raised during a webinar held by the National Cancer Institute (NCI): (1) how structural factors, including neighborhood segregation and obesogenic conditions within racial and ethnic disadvantaged communities, influence disparities in the United States; (2) current research challenges and best ways to address them; and (3) selected priorities of the NCI aimed at addressing multilevel and intersecting factors that influence obesity-related cancer disparities. Further research is needed to understand how residential segregation and neighborhood obesogenic conditions influence cancer prevention and control across the continuum. Identifying the best approaches to address obesity and cancer disparities using social determinants of health framework and community-engaged approaches guided by a structural racism lens will allow researchers to move beyond individual-level approaches.
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  • 文章类型: Journal Article
    以前有报道称,安魂曲鲨鱼(Carcharhinus属)在地中海东部的海洋基础设施周围形成了大型聚集体。虽然这种行为可能会在个人层面提供健身优势,在人类改变的栖息地延长居住对人口持久性的影响尚待评估。在这项工作中,我们调查了以色列燃煤发电和海水淡化站附近鲨鱼的系统地理和人口组成。我们的目的是推断栖息地的使用和聚集行为背后的机制,并强调潜在的保护影响。我们取样,测量,并在2016年至2022年之间释放了70个人,以评估细胞色素C氧化酶I(COI)区域内的遗传变异性,并根据鲨鱼的大小和性别分布分析聚集的结构。此外,我们对在以色列另一个电站收集的死亡参考标本进行了综合计数,以使用上述技术补充物种鉴定。我们的发现表明,成年雌性暗色鲨鱼和雄性沙洲鲨鱼(Carcharhinusobscurus和Carcharhinusplumbeus,分别),每个物种包含两个COI单倍型。在昏暗的鲨鱼中,一种单倍型对应于印度-太平洋血统,另一个与大西洋血统相符。在沙洲鲨鱼中,我们观察到以前在地中海采样的单倍型,红海,西北印度洋,南非,另一种单倍型是我们研究地点独有的,在遗传上比在其他海洋盆地采样的序列更接近前者。这项研究首次表明了系统地理上不同的暗黑和沙洲鲨鱼谱系之间的同胞聚集,这表明地中海东部人类改变的栖息地可能会影响这些物种的分布。根据观察到的偏析模式,我们得出的结论是,该网站不能作为托儿所,分娩,或交配区,并讨论其他值得进一步研究的合理解释。最后,我们强调未来研究的重要方向以及我们的发现对管理和保护的影响。
    Requiem sharks (genus Carcharhinus) have previously been reported to form large aggregations around marine infrastructures in the eastern Mediterranean Sea. While this behaviour may offer fitness advantages at the individual level, the implications of extended residency at human-altered habitats for population persistence have yet to be assessed. In this work, we investigated the phylogeographic and demographic composition of sharks near a coal-fired power and desalination station in Israel. Our aim was to infer habitat use and the mechanisms underlying the aggregation behaviour, and to highlight potential conservation impacts. We sampled, measured, and released 70 individuals between 2016 and 2022 to assess genetic variability within the cytochrome C oxidase I (COI) region and to analyse the aggregation\'s structure based on the sharks\' size and sex distribution. In addition, we performed meristic counts on a reference specimen collected dead at another power station in Israel to supplement species identification using the abovementioned techniques. Our findings indicate size-based sex segregation of adult female dusky and male sandbar sharks (Carcharhinus obscurus and Carcharhinus plumbeus, respectively), with each species comprising two COI haplotypes. In the dusky shark, one haplotype corresponded to an Indo-Pacific lineage, and the other matched an Atlantic lineage. In the sandbar shark, we observed a haplotype previously sampled in the Mediterranean Sea, the Red Sea, the Northwest Indian Ocean, and South Africa, and another haplotype that was unique to our study site and genetically closer to the former than to sequences sampled in other ocean basins. This study provides the first indication of sympatric aggregation amongst phylogeographically distinct dusky and sandbar shark lineages, suggesting that human-altered habitats in the eastern Mediterranean Sea may influence the distribution of these species. Based on the observed segregation pattern, we conclude that the site does not function as a nursery, parturition, or mating area, and discuss other plausible explanations that warrant further research. Finally, we highlight important directions for future research and the implications of our findings for management and conservation.
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  • 文章类型: Journal Article
    预防传染性感染是囊性纤维化(CF)护理的优先事项。这是对CF感染预防和控制干预措施证据的系统回顾的更新。我们的完整协议可以在PROSPERO(CRD42018109999)上找到。我们搜索了包括CF感染预防和控制干预措施的研究和指南。我们纳入了39项研究和7项指南。策略包括:队列或个体隔离,手部卫生,口罩,设备,增强的粘附性或这些的组合。许多研究表明,隔离的传播减少。然而,证据的确定性(使用等级)较低或非常低。大多数指南建议几乎没有证据支持它们,没有更新,因为我们的原始审查。在这方面进行RCT在道德上很困难。基于注册的大规模研究可能是最好的务实方法。感染控制的好处必须与CF患者生活中的入侵相平衡。
    Preventing transmissible infection is a priority in cystic fibrosis (CF) care. This is an update of a systematic review of the evidence for infection prevention and control interventions in CF. Our full protocol can be found on PROSPERO (CRD42018109999). We searched for studies and guidelines which included interventions for infection prevention and control in CF. We included 39 studies and 7 guidelines. Strategies included: cohort or individual segregation, hand hygiene, facemasks, equipment, enhanced adherence or a combination of these. Many studies showed a reduction in transmission with segregation. However, the certainty of evidence (using GRADE) was low or very low. Most guideline recommendations have little evidence to support them, with no updates since our original review. Undertaking RCTs in this area is ethically difficult. Large-scale registry-based studies may be the best pragmatic approach. Benefits of infection control must be balanced against the intrusion in the lives of people with CF.
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  • 文章类型: Journal Article
    隔离是对建立一个有凝聚力的社会的愿望的威胁,可以对其动态进行建模,以帮助设计预防措施。这项工作探讨了城市空间的网络拓扑是否会影响人口隔离的速度的问题。所采用的模拟动力学以这样的方式增强了规范的谢林模型,即它还捕获了代理商偏爱更密集区域的亲和力,这些区域也提供了足够的局部均匀性。结果表明,从真实的城市地图中综合生成的不同网络可以改变隔离率。结果还表明,在所有代理之间的代理边缘程度分布上使用熵迹与隔离相关,从而增强了物理启发的社会系统建模的相关性。这项调查表明,有可能在城市规划阶段探索和选择不利于隔离运动的网络安排,从而降低比率。另一个发现是,熵测度与此类建模工作的常见统计量密切相关。
    Segregation is a threat to the aspirations of producing a cohesive society and modelling its dynamics can be done in order to help design preventative measures. This work explores the question of whether the network topologies of urban spaces can affect the pace at which populations can become segregated. The simulation dynamics employed augment the canonical Schelling model in such a way that it also captures the affinity for agents to prefer denser regions which also offer sufficient local homogeneity. It is shown that different networks synthetically generated and from real city maps can alter the rate of segregation. The results also show that using the entropy trace on the distribution of agent edge degree across all agents correlates with the segregation reinforcing the relevance of physics inspired modeling of social systems. This investigation shows that it is possible to explore and select network arrangements which can be less conducive towards segregation movements during the stages of urban planning so that the rate is reduced. An additional finding is that the entropic measure is closely associated with the common statistic for such modeling efforts.
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  • 文章类型: Journal Article
    双金属纳米结构是开发酶模拟物的有希望的候选人,然而,破译对其催化性能的结构影响提出了重大挑战。通过利用纳米晶体气凝胶的结构多功能性,这项研究报告了在三种代表性结构配置中精确控制Au-Pt双金属结构,包括隔离,合金,和核壳结构。受益于协同效应,这些双金属气凝胶与它们的单金属对应物相比,表现出改进的过氧化物酶和葡萄糖氧化酶样催化性能,在催化葡萄糖级联反应中释放出巨大的潜力。值得注意的是,分离的Au-Pt气凝胶显示出最佳的催化活性,比合金和核壳变体高2.80和3.35倍,分别。这种增强的活性归因于分离结构内的高密度Au-Pt界面边界,这促进了更大的底物亲和力和优异的催化效率。这项工作不仅阐明了双金属催化剂的结构-性质关系,而且拓宽了气凝胶在生物传感和生物检测中的应用范围。
    Bimetallic nanostructures are promising candidates for the development of enzyme-mimics, yet the deciphering of the structural impact on their catalytic properties poses significant challenges. By leveraging the structural versatility of nanocrystal aerogels, this study reports a precise control of Au-Pt bimetallic structures in three representative structural configurations, including segregated, alloy, and core-shell structures. Benefiting from a synergistic effect, these bimetallic aerogels demonstrate improved peroxidase- and glucose oxidase-like catalytic performances compared to their monometallic counterparts, unleashing tremendous potential in catalyzing the glucose cascade reaction. Notably, the segregated Au-Pt aerogel shows optimal catalytic activity, which is 2.80 and 3.35 times higher than that of the alloy and core-shell variants, respectively. This enhanced activity is attributed to the high-density Au-Pt interface boundaries within the segregated structure, which foster greater substrate affinity and superior catalytic efficiency. This work not only sheds light on the structure-property relationship of bimetallic catalysts but also broadens the application scope of aerogels in biosensing and biological detections.
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  • 文章类型: Journal Article
    Between 1867 and 1933, the understanding of leprosy within the colonial medical establishment in Bombay city was fractured on two issues: whether leprosy was contagious and whether individuals with leprosy should be segregated. This article explores how legislation paved the way for resolving these issues in Bombay between 1867 and 1933. Furthermore, the article seeks to problematize the notion of \"diseased bodies\" or \"lepers\" through legislation to protect healthy individuals from possible degeneration. Leprosy in Bombay reflected the anxieties of the city\'s business elite who were averse to accommodating patients from other parts of British India. In addition, the article studies leprosy and \"lepers\" by analyzing archival documents and public health reports within the context of Bombay city.
    Entre 1867 et 1933, la lèpre au sein de l\'institution médicale coloniale de la ville de Bombay a été débattue autour de deux questions : était-elle contagieuse et les personnes atteintes devaient-elles faire l\'objet d\'une ségrégation? Cet article explore la manière dont la législation a ouvert la voie à la résolution de ces questions à Bombay pour la période étudiée. En outre, l\'article cherche à problématiser la notion de « corps malades » ou de « lépreux » au sein d\'une législation qui visait à protéger les individus sains d\'une éventuelle dégénérescence. La lèpre à Bombay reflétait les inquiétudes de l’élite économique de la ville, peu encline à accueillir des patients originaires d\'autres régions de l\'Inde britannique. L\'article se penche également sur la lèpre et les « lépreux » en analysant des documents d\'archives et des rapports de santé publique portant sur la ville de Bombay.
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  • 文章类型: Journal Article
    语音感知需要时空分离的听觉-视觉线索的结合。相应的大脑网络级信息处理可以通过两种互补机制来表征:功能隔离,指的是在整个大脑中孤立或分布式模块中进行处理的定位。以及与相关功能模块之间的合作有关的集成。这里,我们使用功能磁共振成像记录证明了多感官言语刺激的主观感知体验,真实而虚幻,以偏析-积分的差分状态表示。我们通过参数控制了虚幻/跨模态感知的主体间变异性,通过在McGurk范式中的语音的不一致听觉视觉表达中引入时间滞后。使用两种替代的计算方法捕获了隔离-积分平衡的状态。首先,使用标准化参数统计方法鉴定了定义为感知结合网络(PBN)的感觉信号的跨模态结合模块,并计算了它们与所有其他大脑区域的时间相关性.随着越来越多的虚幻感知,PBN的大部分节点显示与大脑其余部分的合作减少,反映了高度隔离但全球一体化程度降低的国家。第二,使用图论测度,对分离-整合的改变模式进行了交叉验证.
    Speech perception requires the binding of spatiotemporally disjoint auditory-visual cues. The corresponding brain network-level information processing can be characterized by two complementary mechanisms: functional segregation which refers to the localization of processing in either isolated or distributed modules across the brain, and integration which pertains to cooperation among relevant functional modules. Here, we demonstrate using functional magnetic resonance imaging recordings that subjective perceptual experience of multisensory speech stimuli, real and illusory, are represented in differential states of segregation-integration. We controlled the inter-subject variability of illusory/cross-modal perception parametrically, by introducing temporal lags in the incongruent auditory-visual articulations of speech sounds within the McGurk paradigm. The states of segregation-integration balance were captured using two alternative computational approaches. First, the module responsible for cross-modal binding of sensory signals defined as the perceptual binding network (PBN) was identified using standardized parametric statistical approaches and their temporal correlations with all other brain areas were computed. With increasing illusory perception, the majority of the nodes of PBN showed decreased cooperation with the rest of the brain, reflecting states of high segregation but reduced global integration. Second, using graph theoretic measures, the altered patterns of segregation-integration were cross-validated.
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  • 文章类型: Journal Article
    结合晶界(GB)效应和辐照加速扩散,建立了Fe-Cr-Al合金析出的相场模型。结合了辐射源和晶界效应,以扩大Fe-Cr-Al沉淀相场模型的适用性。该模型首先用于模拟单晶合金中富Crα'相的析出。分析了沉淀速率和沉淀相的尺寸分布。随后,该模型用于模拟双晶系统中GB的偏析,分析这些边界附近Cr的富集和Al的耗尽。模拟结果与参考文献中报道的实验观察结果一致。最后,该模型用于模拟多晶Fe-Cr-Al系统中的沉淀。模拟结果表明,GBs的存在会导致Cr和Al含量增加的局部区域以及与这些边界相邻的耗尽区域的形成。GBs还降低了晶粒内形成相的数量和沉淀速率。
    A phase-field model for the precipitation of Fe-Cr-Al alloy is established incorporating grain boundary (GB) effects and irradiation-accelerated diffusion. The radiation source and grain boundary effect are incorporated to broaden the applicability of the Fe-Cr-Al precipitated phase-field model. The model is firstly employed to simulate the precipitation of the Cr-rich α\' phase in a single-crystal alloy. The precipitation rate and the size distribution of the precipitated phase were analyzed. Subsequently, the model is utilized to simulate segregation at GBs in a double-crystal system, analyzing the enrichment of Cr and depletion of Al near these boundaries. The simulation results are consistent with experimental observations reported in the references. Finally, the model is applied to simulate the precipitation in a polycrystalline Fe-Cr-Al system. The simulated results revealed that the presence of GBs induces the formation of localized regions with enhanced Cr and Al content as well as depleted zones adjacent to these boundaries. GBs also diminish both the quantity and precipitation rate of the formed phase within the grains.
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  • 文章类型: Journal Article
    冥想,旨在提高一个人调节认知能力的心理训练,在临床医学中得到了广泛的应用。然而,冥想影响大脑活动的机制尚不清楚。为了探索这个问题,在2项高级认知任务(冥想和心理计算)和放松静息状态(对照)期间,20名长期冥想者和20名非冥想者记录了脑电图数据.然后,提取并比较两组脑电图的功率谱密度和相位同步。此外,机器学习用于区分每个组内的状态。我们发现,冥想组显示出明显高于对照组的分类精度和计算效率。然后,在计算任务期间,与松弛状态相比,禅修者的伽玛反应的功率和全局相位同步均下降;然而,对照组未观察到这种变化.对我们观察结果的一个潜在解释是,冥想通过神经可塑性机制改善了大脑的灵活性。总之,我们提供了强有力的证据表明,长期的冥想经验可以在大脑活动中产生可检测的神经生理变化,这可能会增强大脑的功能隔离和/或专业化。
    Meditation, mental training that aims to improve one\'s ability to regulate their cognition, has been widely applied in clinical medicine. However, the mechanism by which meditation affects brain activity is still unclear. To explore this question, electroencephalogram data were recorded in 20 long-term meditators and 20 nonmeditators during 2 high-level cognitive tasks (meditation and mental calculation) and a relaxed resting state (control). Then, the power spectral density and phase synchronization of the electroencephalogram were extracted and compared between these 2 groups. In addition, machine learning was used to discriminate the states within each group. We found that the meditation group showed significantly higher classification accuracy and calculation efficiency than the control group. Then, during the calculation task, both the power and global phase synchronism of the gamma response decreased in meditators compared to their relaxation state; yet, no such change was observed in the control group. A potential explanation for our observations is that meditation improved the flexibility of the brain through neural plastic mechanism. In conclusion, we provided robust evidence that long-term meditation experience could produce detectable neurophysiological changes in brain activity, which possibly enhance the functional segregation and/or specialization in the brain.
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