190 research outputs found

    First-Principles Calculations of the Structure Stability and Mechanical Properties of LiFeAs and NaFeAs under Pressure

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    The lattice parameters and elastic constants of the tetragonal LiFeAs and NaFeAs under different pressures have been investigated by using the first-principles calculations. It is found that their lattice parameters at 0 GPa are in agreement with the available experimental data. By the elastic stability criteria under isotropic pressure, it is found that LiFeAs and NaFeAs with the tetragonal structure are not mechanically stable above 16 GPa and 18 GPa, respectively. Besides, Pugh’s modulus ratio, Poisson’s ratio, Vickers hardness, and elastic anisotropy factors of LiFeAs in the pressure range of 0–16 GPa and NaFeAs in the pressure range of 0–18 GPa are systematically investigated. It is shown that their ductilities increase with increasing pressure, and the ductility of NaFeAs is superior to that of LiFeAs under different pressures

    The First Principle in Late Neoplatonism: A Study of the One's Causality in Proclus and Damascius

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    One of the main issues that dominates Neoplatonism in late antique philosophy of the 3rd–6th centuries A.D. is the nature of the first principle, called the ‘One’. From Plotinus onward, the principle is characterized as the cause of all things, since it produces the plurality of intelligible Forms, which in turn constitute the world’s rational and material structure. Given this, the tension that faces Neoplatonists is that the One, as the first cause, must transcend all things that are characterized by plurality—yet because it causes plurality, the One must anticipate plurality within itself. This becomes the main mo- tivation for this study’s focus on two late Neoplatonists, Proclus (5th cent. A.D.) and Damascius (late 5th–early 6th cent. A.D.): both attempt to address this tension in two rather different ways. Proclus’ attempted solution is to posit intermediate principles (the ‘henads’) that mirror the One’s nature, as ‘one’, but directly cause plurality. This makes the One only a cause of unity, while its production of plurality is mediated by the henads that it produces. Damascius, while appropriating Proclus’ framework, thinks that this is not enough: if the One is posed as a cause of all things, it must be directly related to plurality, even if its causality is mediated through the henads. Damascius then splits Proclus’ One into two entities: (1) the Ineffable as the first ‘principle’, which is absolutely transcendent and has no causal relation; and (2) the One as the first ‘cause’ of all things, which is only relatively transcendent under the Ineffable. Previous studies that compare Proclus and Damascius tend to focus either on the Ineffable or a skeptical shift in epistemology, but little work has been done on the causal framework which underlies both figures’ positions. Thus, this study proposes to focus on the causal frameworks behind each figure: why and how does Proclus propose to assert that the One is a cause, at the same time that it transcends its final effect? And what leads Damascius to propose a notion of the One’s causality that no longer makes it transcendent in the way that a higher principle, like the Ineffable, is? The present work will answer these questions in two parts. In the first, Proclus’ and Damascius’ notions of causality will be examined, insofar as they apply to all levels of being. In the second part, the One’s causality will be examined for both figures: for Proclus, the One’s causality in itself and the causality of its intermediate principles; for Damascius, the One’s causality, and how the Ineffable is needed to explain the One. The outcome of this study will show that Proclus’ framework results in an inner tension that Damascius is responding to with his notion of the One. While Damascius’ own solution implies its own tension, he at least solves a difficulty in Proclus—and in so doing, partially returns to a notion of the One much like Iamblichus’ and Plotinus’ One

    Active Semisupervised Clustering Algorithm with Label Propagation for Imbalanced and Multidensity Datasets

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    The accuracy of most of the existing semisupervised clustering algorithms based on small size of labeled dataset is low when dealing with multidensity and imbalanced datasets, and labeling data is quite expensive and time consuming in many real-world applications. This paper focuses on active data selection and semisupervised clustering algorithm in multidensity and imbalanced datasets and proposes an active semisupervised clustering algorithm. The proposed algorithm uses an active mechanism for data selection to minimize the amount of labeled data, and it utilizes multithreshold to expand labeled datasets on multidensity and imbalanced datasets. Three standard datasets and one synthetic dataset are used to demonstrate the proposed algorithm, and the experimental results show that the proposed semisupervised clustering algorithm has a higher accuracy and a more stable performance in comparison to other clustering and semisupervised clustering algorithms, especially when the datasets are multidensity and imbalanced

    Isolation and Functional Analysis of PISTILLATA Homolog From Magnolia wufengensis

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    PISTILLATA (PI) homologs are crucial regulators of flower development in angiosperms. In this study, we isolated the MAwuPI homolog from Magnolia wufengensis, a basal angiosperm belonging to the Magnoliaceae. Molecular phylogenetic analysis suggested that MAwuPI was grouped into the PI/GLO lineages of B-class MADS-box gene with the distinctive PI motif. Further expression profiling analysis showed that MAwuPI was expressed in tepals and stamens but not in juvenile leaves and carpels, similar to the spatial expression pattern of AtPI in Arabidopsis. Interestingly, MAwuPI had higher expression level in inner-tepals than in outer-tepals, whereas the M. wufengensis flower is homochlamydeous. Moreover, ectopic expression of MAwuPI in Arabidopsis pi-1 mutant emerged filament-like structures but had no obvious petals, suggesting a partial phenotypic recovery of pi-1 mutant. The features of MAwuPI in the expression pattern and gene function improved our acknowledgment of B-class genes in M. wufengensis, and contributed to the clarification of M. wufengensis evolution status and relations with other sibling species in molecular perspective

    Voluntary postural sway control and mobility in adults with low back pain

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    IntroductionLow back pain (LBP) is associated with altered somatosensory perception, which is involved in both involuntary and voluntary control of posture. Currently, there is a lack of methods and tools for assessing somatosensory acuity in patients with LBP. The purpose of this study was (1) to assess the reliability of the sway discrimination apparatus (SwayDA) (2) to evaluate the differences in somatosensory acuity between patients with LBP and pain-free individuals, and (3) to examine relationships between somatosensory acuity, severity of LBP, and mobility in patients with LBP.MethodsTwenty participants (10 patients with LBP and 10 matched asymptomatic controls) were recruited in a test–retest reliability test. Another 56 participants were recruited for this study with 28 individuals presenting with LBP and a further twenty-eight being asymptomatic. The SwayDA was custom-built to measure somatosensory perception during voluntary anterior–posterior (SwayDA-AP), medial-lateral to the dominant side (SwayDA-ML-D), and non-dominant side (SwayDA-ML-ND) postural sway control. Participants also completed mobility tests, including 10 times and 1-min sit-to-stand tests (10-STS, 1 m-STS). The area under the receiver operating characteristic curve (AUC) was calculated to quantify somatosensory acuity in discriminating different voluntary postural sway extents.ResultsThe ICC (2.1) for the SwayDA-AP, SwayDA-ML-D, and SwayDA-ML-ND were 0.741, 0.717, and 0.805 with MDC95 0.071, 0.043, and 0.050. Patients with LBP demonstrated significantly lower SwayDA scores (tSwayDA-AP = −2.142, p = 0.037; tSwayDA-ML-D = -2.266, p = 0.027) than asymptomatic controls. The AUC values of the SwayDA-AP test were significantly correlated with ODI (rSwayDA-AP-ODI = −0.391, p = 0.039). Performances on the 1 m-STS and the 10-STS were significantly correlated with the AUC scores from all the SwayDA tests (−0.513 ≤ r ≤ 0.441, all p < 0.05).DiscussionThe SwayDA tests evaluated showed acceptable reliability in assessing somatosensory acuity during voluntary postural sway. Somatosensory acuity was diminished in patients with LBP compared to asymptomatic controls. In patients with LBP, lower somatosensory acuity was associated with increased LBP-related disability. Future research could focus on investigating the factors contributing to the decreased somatosensory perception and mobility in individuals with LBP

    Effect of Wearable Sensor-Based Exercise on Musculoskeletal Disorders in Individuals With Neurodegenerative Diseases: A Systematic Review and Meta-Analysis

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    BackgroundThe application of wearable sensor technology in an exercise intervention provides a new method for the standardization and accuracy of intervention. Considering that the deterioration of musculoskeletal conditions is of serious concern in patients with neurodegenerative diseases, it is worthwhile to clarify the effect of wearable sensor-based exercise on musculoskeletal disorders in such patients compared with traditional exercise.MethodsFive health science-related databases, including PubMed, Cochrane Library, Embase, Web of Science, and Ebsco Cumulative Index to Nursing and Allied Health, were systematically searched. The protocol number of the study is PROSPERO CRD42022319763. Randomized controlled trials (RCTs) that were published up to March 2022 and written in English were included. Balance was the primary outcome measure, comprising questionnaires on postural stability and computerized dynamic posturography. The secondary outcome measures are motor symptoms, mobility ability, functional gait abilities, fall-associated self-efficacy, and adverse events. Stata version 16.0 was used for statistical analysis, and the weighted mean difference (WMD) was selected as the effect size with a 95% confidence interval (CI).ResultsFifteen RCTs involving 488 participants with mean ages ranging from 58.6 to 81.6 years were included in this review, with 14 of them being pooled in a quantitative meta-analysis. Only five included studies showed a low risk of bias. The Berg balance scale (BBS) was used in nine studies, and the pooled data showed a significant improvement in the wearable sensor-based exercise group compared with the traditional exercise group after 3–12-week intervention (WMD = 1.43; 95% CI, 0.50 to 2.36, P = 0.003). A significant change in visual score was found both post-assessment and at 1-month follow-up assessment (WMD = 4.38; 95% CI, 1.69 to 7.07, P = 0.001; I2 = 0.0%). However, no significant differences were found between the two groups in the secondary outcome measures (all p > 0.05). No major adverse events were reported.ConclusionThe wearable sensor-based exercise had advantages in improving balance in patients with neurodegenerative diseases, while there was a lack of evidence in motor symptoms, mobility, and functional gait ability enhancement. Future studies are recommended to construct a comprehensive rehabilitation treatment system for the improvement in both postural control and quality of life.Systematic Review Registrationhttp://www.crd.york.ac.uk/prospero/, identifier CRD42022319763

    Sedimentary ancient DNA reveals past ecosystem and biodiversity changes on the Tibetan Plateau: Overview and prospects

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    Alpine ecosystems on the Tibetan Plateau are being threatened by ongoing climate warming and intensified human activities. Ecological time-series obtained from sedimentary ancient DNA (sedaDNA) are essential for understanding past ecosystem and biodiversity dynamics on the Tibetan Plateau and their responses to climate change at a high taxonomic resolution. Hitherto only few but promising studies have been published on this topic. The potential and limitations of using sedaDNA on the Tibetan Plateau are not fully understood. Here, we (i) provide updated knowledge of and a brief introduction to the suitable archives, region-specific taphonomy, state-of-the-art methodologies, and research questions of sedaDNA on the Tibetan Plateau; (ii) review published and ongoing sedaDNA studies from the Tibetan Plateau; and (iii) give some recommendations for future sedaDNA study designs. Based on the current knowledge of taphonomy, we infer that deep glacial lakes with freshwater and high clay sediment input, such as those from the southern and southeastern Tibetan Plateau, may have a high potential for sedaDNA studies. Metabarcoding (for microorganisms and plants), metagenomics (for ecosystems), and hybridization capture (for prehistoric humans) are three primary sedaDNA approaches which have been successfully applied on the Tibetan Plateau, but their power is still limited by several technical issues, such as PCR bias and incompleteness of taxonomic reference databases. Setting up high-quality and open-access regional taxonomic reference databases for the Tibetan Plateau should be given priority in the future. To conclude, the archival, taphonomic, and methodological conditions of the Tibetan Plateau are favorable for performing sedaDNA studies. More research should be encouraged to address questions about long-term ecological dynamics at ecosystem scale and to bring the paleoecology of the Tibetan Plateau into a new era
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