Clustering Application for Condition-Based Maintenance in Time-Varying Processes: A Review Using Latent Dirichlet Allocation

In the field of industrial process monitoring, scholars and practitioners are increasing interest in time-varying processes , where different phases are implemented within an unknown time frame. The measurement of process parameters could inform about the health state of the production assets, or products, but only if the measured parameters are coupled with the specific phase identification. A combination of values could be common for one phase and uncommon for another phase; thus, the same combination of values shows a high or low probability depending on the specific phase. The automatic identification of the production phase usually relies on clustering techniques. This is largely due to the difficulty of finding training fault data for supervised models. With these two considerations in mind, this contribution proposes the Latent Dirichlet Allocation as a natural language-processing technique for reviewing the topic of clustering applied in time-varying contexts, in the maintenance field. Thus, the paper presents this innovative methodology to analyze this specific research fields, presenting the step-by-step application and its results, with an overview of the theme.

Cross-population coupling of neural activity based on Gaussian process current source densities

Because local field potentials (LFPs) arise from multiple sources in different spatial locations, they do not easily reveal coordinated activity across neural populations on a trial-to-trial basis. As we show here, however, once disparate source signals are decoupled, their trial-to-trial fluctuations become more accessible, and cross-population correlations become more apparent. To decouple sources we introduce a general framework for estimation of current source densities (CSDs). In this framework, the set of LFPs result from noise being added to the transform of the CSD by a biophysical forward model, while the CSD is considered to be the sum of a zero-mean, stationary, spatiotemporal Gaussian process, having fast and slow components, and a mean function, which is the sum of multiple time-varying functions distributed across space, each varying across trials. We derived biophysical forward models relevant to the data we analyzed. In simulation studies this approach improved identification of source signals compared to existing CSD estimation methods. Using data recorded from primate auditory cortex, we analyzed trial-to-trial fluctuations in both steady-state and task-evoked signals. We found cortical layer-specific phase coupling between two probes and showed that the same analysis applied directly to LFPs did not recover these patterns. We also found task-evoked CSDs to be correlated across probes, at specific cortical depths. Using data from Neuropixels probes in mouse visual areas, we again found evidence for depth-specific phase coupling of primary visual cortex and lateromedial area based on the CSDs.

Portulaca oleracea shows no ameliorative potential on ovariectomy-induced hormonal and estrous cycle dysregulation in normal cyclic rats: An experimental study

Background: Portulaca oleracea (PO) is a widely known plant utilized for its medicinal attributes in the treatment of different illnesses. Objective: To investigate the effect of methanolic extract of PO (MEPO) on ovariectomy-induced reproductive toxicity in normal cyclic rats. Materials and Methods: Twenty 10-wk-old normal cyclic rats weighing 110-200 g were randomly divided into four groups (n = 5/group). Group A served as the control and received distilled water only. Group B was ovariectomized without treatment, while groups C and D were ovariectomized but treated with 400 and 800 mg/kg of MEPO, respectively, for 14 days. At the end of the experiment, body weight, serum hormonal levels, and estrous cycles were monitored across the groups. Results: Groups B, C, and D showed estrous cycle dysregulation and specific phase arrest when compared with the control. While a significant decrease in estradiol (p ≤ 0.001) and testosterone levels (p ≤ 0.001) were observed in groups B, C, and D, only groups C and D showed a significant increase in progesterone level when compared with the control (p ≤ 0.001, p = 0.01, respectively). Conclusion: The administration of 400 and 800 mg/kg MEPO is ineffective in ameliorating estrous cycle disruption and hormonal changes seen in ovariectomized normal cyclic adult Wistar rats. Key words: Portulaca oleracea, Wistar rat, Ovariectomy, Estrous cycle, Hormones.

Membrane architecture and adherens junctions contribute to strong Notch pathway activation

ABSTRACT The Notch pathway mediates cell-to-cell communication in a variety of tissues, developmental stages and organisms. Pathway activation relies on the interaction between transmembrane ligands and receptors on adjacent cells. As such, pathway activity could be influenced by the size, composition or dynamics of contacts between membranes. The initiation of Notch signalling in the Drosophila embryo occurs during cellularization, when lateral cell membranes and adherens junctions are first being deposited, allowing us to investigate the importance of membrane architecture and specific junctional domains for signalling. By measuring Notch-dependent transcription in live embryos, we established that it initiates while lateral membranes are growing and that signalling onset correlates with a specific phase in their formation. However, the length of the lateral membranes per se was not limiting. Rather, the adherens junctions, which assemble concurrently with membrane deposition, contributed to the high levels of signalling required for transcription, as indicated by the consequences of α-Catenin depletion. Together, these results demonstrate that the establishment of lateral membrane contacts can be limiting for Notch trans-activation and suggest that adherens junctions play an important role in modulating Notch activity.

'He moved then?’: The management of worry-indicative information requests in moderate and high-risk fetal ultrasounds

The present study analyzes video-recorded fetal ultrasound scans held in a moderate and high-risk pregnancy ward at a Brazilian public hospital. Informed by Multimodal Conversation Analysis (Mondada, 2018), it investigates the ethnomethods participants employ to manage worry-indicative concerns whose presentation is initiated by pregnant women in a medical exam that does not typically comprise a specific phase for that (Nishizaka, 2010, 2011b, 2014). The analysis shows that pregnant women orient to three environments to request worry-indicative information: (i) topic, (ii) image, (iii) phase transition, tailoring the design of their requests to each particular environment. The findings reveal that pregnant women are highly agentive in finding optimal opportunities to raise their concerns and to mobilize health professionals to respond to them. The physicians performing the scans respond to those requests while dealing with the contingencies inherent to the context of fetal ultrasounds and that have implications in attending to the requests. The results unveil the interplay between the pregnant women’s ethnomethods of raising concerns where ‘normality’ is constantly at stake and the health professionals’ ethnomethods in attending to those demands while orchestrating the distinct semiotic resources involved in the multiactivity setting of ultrasound scans.

SATB1 undergoes isoform-specific phase transitions in T cells

Intracellular space is demarcated into functional membraneless organelles and nuclear bodies via the process of phase separation. Phase transitions are involved in many functions linked to such bodies as well as in gene expression regulation and other cellular processes. In this work we describe how the genome organizer SATB1 utilizes its prion-like domains to undergo phase transitions. We have identified two SATB1 isoforms with distinct biophysical behavior and showed how phosphorylation and interaction with nuclear RNA, impact their phase transitions. Moreover, we show that SATB1 is associated with transcription and splicing, both of which evinced deregulation in Satb1 knockout mice. Thus, the tight regulation of different SATB1 isoforms levels and their post-translational modifications are imperative for SATB1's physiological roles in T cell development while their deregulation may be linked to disorders such as cancer.

System Hazard Analysis of Tower Crane in Different Phases on Construction Site

Tower crane accidents frequently occur in the construction industry, often resulting in casualties. The utilization of tower cranes involves multiple phases including installation, usage, climbing, and dismantling. Moreover, the hazards associated with the use of tower cranes can change and be propagated during phase alternation. However, past studies have paid less attention to the differences and hazard propagations between phases. In this research, these hazards are investigated during different construction phases. The propagation of hazards between phases is analyzed to develop appropriate safety management protocols according to each specific phase. Finally, measures are suggested to avoid an adverse impact between the phases. A combined method is also proposed to identify hazard propagation, which serves as a reference and contributes to safety management and accident prevention during different tower crane phases in the construction process.

A specific phase of transcranial alternating current stimulation at the β frequency boosts repetitive paired-pulse TMS-induced plasticity

Transcranial alternating current stimulation (tACS) at 20 Hz (β) has been shown to modulate motor evoked potentials (MEPs) when paired with transcranial magnetic stimulation (TMS) in a phase-dependent manner. Repetitive paired-pulse TMS (rPPS) with I-wave periodicity (1.5 ms) induced short-lived facilitation of MEPs. We hypothesized that tACS would modulate the facilitatory effects of rPPS in a frequency- and phase-dependent manner. To test our hypothesis, we investigated the effects of combined tACS and rPPS. We applied rPPS in combination with peak or trough phase tACS at 10 Hz (α) or β, or sham tACS (rPPS alone). The facilitatory effects of rPPS in the sham condition were temporary and variable among participants. In the β tACS peak condition, significant increases in single-pulse MEPs persisted for over 30 min after the stimulation, and this effect was stable across participants. In contrast, β tACS in the trough condition did not modulate MEPs. Further, α tACS parameters did not affect single-pulse MEPs after the intervention. These results suggest that a rPPS-induced increase in trans-synaptic efficacy could be strengthened depending on the β tACS phase, and that this technique could produce long-lasting plasticity with respect to cortical excitability.

An Efficient CNN for Hand X-Ray Classification of Rheumatoid Arthritis

Hand Radiography (RA) is one of the prime tests for checking the progress of rheumatoid joint inflammation in human bone joints. Recognizing the specific phase of RA is a difficult assignment, as human abilities regularly curb the techniques for it. Convolutional neural network (CNN) is the center for hand recognition for recognizing complex examples. The human cerebrum capacities work in a high-level way, so CNN has been planned depending on organic neural-related organizations in humans for imitating its unpredictable capacities. This article accordingly presents the convolutional neural network (CNN) which has the ability to naturally gain proficiency with the qualities and anticipate the class of hand radiographs from an expansive informational collection. The reproduction of the CNN halfway layers, which depict the elements of the organization, is likewise appeared. For arrangement of the model, a dataset of 290 radiography images is utilized. The result indicates that hand X-rays are rated with an accuracy of 94.46% by the proposed methodology. Our experiments show that the network sensitivity is observed to be 0.95 and the specificity is observed to be 0.82.

Design and modeling of a photonic integrated device for optical vortex generation in a silicon waveguide

We propose and numerically verify a design of the photonic integrated circuit for in-plane generation of a 1st azimuthal order vortex mode in dielectric rectangular waveguides. Radiation is introduced into the proposed structure in a standard way through two grating couplers. Applying a mode coupling and specific phase shift, a field with the required amplitude-phase distribution is formed directly in the output waveguide. The geometric dimensions of the device are simulated and optimized to fit the technological parameters of the silicon-on-insulator platform.