Initial Point Research Articles

The importance of drug symbols and halal logos in the pharmaceutical industry: Effect, understanding, and implementation

With its predominantly Muslim population, Indonesia has significant potential in pharmaceuticals and herbal products, making it a focal point for government initiatives to drive growth in the sector. Despite these efforts, compliance with halal standards and obtaining halal certificates still face many challenges. This research examines the efforts to fulfill halal certification obligations by implementing halal standards in pharmaceutical and herbal products. This research uses a descriptive qualitative study; the data was collected through observational reviews and interviews and supplemented with a comprehensive literature study, which includes various sources such as journals, books, online media, and other additional references. This study reveals that setting standards or halal certification involves three parties, namely the Halal Product Assurance Organizing Agency (BPJPH), the Halal Examining Agency (LPH), and the Indonesian Council of Ulama (MUI). BPJPH implements the halal product guarantee. Then BPJPH will submit it to Lembaga Pengkajian Pangan, Obat-obatan dan Kosmetika (LPPOM) as LPH to check the adequacy of documents, compile audits, conduct audits, hold auditor meetings, issue audit memoranda, and submit audit result records to the MUI Halal Fatwa Session. Together with the Fatwa Committee, MUI determines the level of halalness of the product based on the audit results and issues a MUI Halal Decree. Keywords: Herbs, Halal Industry, Halal Certificate, Medicines

Prevalence and Determinants of Prehospital Impression of Stroke in Ischemic Stroke Patients.

Emergency Medical Services (EMS) clinicians are front-line in evaluating patients with stroke in the community. Their ability to correctly identify stroke influences downstream management decisions. We sought to use a large national database of prehospital clinical data to determine risk factors associated with missed EMS stroke identification. Retrospective study examining EMS evaluation of adults with Emergency Department (ED) stroke diagnosis. We leveraged the ESO Data Collaborative research dataset containing EHR data from 2019-2022 that has a subset of encounters with linked hospital diagnostic codes. Our primary outcome was the presence of an EMS diagnosis of stroke. We evaluated the association between demographic and clinical variables with EMS stroke identification using Pearson χ2 test for demographic variables and multivariable GLM for clinical variables with adjustment for demographic variables. We identified 34,504 EMS encounters for patients with ED stroke diagnosis. Of these, 11,077 (32.1%) strokes had missed EMS stroke identification and instead had an EMS impression of "Generalized Weakness" (25.9%), "Altered Level of Consciousness" (24.9%), and "Dizziness" (7.2%). Patients more likely to have missed prehospital stroke identification were of Black race (p=0.0001) and Hispanic ethnicity (p=0.0001). Clinical variables associated with higher risk of missed EMS stroke identification were suspected alcohol or drug use (RR 1.48, 95% CI 1.37-1.59), low GCS (RR 1.17, 95% CI 1.10-1.24), tachycardia (RR 1.05, 95% CI 1.01-1.09), and hypotension (RR 1.47, 95% CI 1.34-1.61). Approximately 1-in-3 patients transported by EMS did not have their stroke identified in the prehospital setting. Factors associated with lower odds of missed EMS stroke identification provide a starting point for future performance improvement initiatives.

Research on the Application of Information Visualization Design Based on the Three-level Theory of Emotions

As society progresses, environmental challenges have emerged as a central concern in modern discourse. The degradation of ecosystems has led to the endangerment and extinction of numerous plant species. Moreover, the overwhelming influx of information available to individuals often hampers their understanding of the significance of these endangered species. Conventional written narratives are frequently inadequate in fulfilling the audience’s informational needs. As a nascent medium for scientific communication, information visualization presents an innovative and effective approach for individuals to swiftly acquire and interpret data. This paper concentrates on the endangered aquatic flora within the South China Botanical Garden, grounded in a three-tiered emotional theory framework. Strategies are developed across instinctual, behavioral, and reflective dimensions. The outlined strategic goals aim to elevate design aesthetic literacy, broaden cognitive processing capability, and enhance the efficiency of information dissemination. By employing endangered aquatic plants as a focal point for design initiatives in the South China Botanical Garden and integrating it with the theoretical framework, the objective is to present information regarding these vulnerable species in a more direct, inventive, and concise manner. This methodology aspires to raise public awareness surrounding the conservation of endangered plant life.

Crack propagation in TPMS scaffolds under monotonic axial load: Effect of morphology

In this paper, the mechanical behaviour and failure of porous additively manufactured (AM) polylactide (PLA) scaffolds based on the triply periodic minimal surfaces (TPMS) is investigated using numerical calculations of their unit cells and representative volumes. The strain-amplification factor is chosen as the main parameter, and the most critical locations for failure of different types of scaffold structures are evaluated. The results obtained are presented in comparison with a multiple-crack-growth algorithm using the extended finite element method (XFEM), underpinned by the experimentally obtained fracture properties of PLA. The effect of morphology of TPMS structures on the pre-critical, critical and post-critical behaviours of scaffolds under monotonic loading regimes is assessed. The results provide an understanding of the fracture behaviour and main risk points for crack initiation in structures of AM-PLA scaffolds based on typical commonly used types of TPMS, as well as the influence of structure type and external load on this behaviour.

Unplanned hospital admissions within 24 h after 53,185 surgical procedures at a U.S. ambulatory surgery center

BackgroundUnplanned admission after surgery at an ambulatory surgery center (ASC) is an established measure of the quality of care and can affect the patient’s experience. Previous studies on this topic are generally dated, focused on a single specialty, or studied 30-day admissions after ambulatory surgery. Few studies have reported admission within 24 h after surgery at an ASC which is a different but important measure of the quality of anesthetic and surgical care. Understanding admissions within 24 h of surgery can identify opportunities for improvement immediately after surgery. Therefore, our study was designed to assess the incidence and risk factors for unplanned hospital admissions within 24 h after surgery performed at a hospital ASC.MethodsAfter Institutional Review Board approval, a retrospective analysis was performed on all adult patients who underwent surgery at a US ASC between January 1, 2016, and December 31, 2022. Data were obtained from the hospital’s electronic medical record. The study sample was divided into two groups: those with an unplanned hospital admission within 24 h after surgery and those without an unplanned hospital admission. To evaluate risk factors for unplanned hospital admissions, univariate analyses with p value < 0.05 were utilized to identify significant patient variables related to hospital admissions. These variables were further adjusted using a multivariable Firth logistic regression. Descriptive statistics were used to explore the number of patients in different variable categories.ResultsOverall, 53,185 cases were identified for the 7-year period. The incidence of unplanned hospital admission over this period was 0.09% (95% CI 0.07–0.1122%; ranging from 0.05 to 0.12% per year. In the multivariable model, surgery duration (OR 1.010, 95% CI 1.007–1.012, p value < 0.0001), peripheral vascular disease (OR 14.489, 95% CI 4.862–43.174, p value < 0.0001), and deep venous thrombosis (OR 5.527, 95% CI 1.909–16.001, p value = 0.0016) were significantly associated with unplanned hospital admission.ConclusionThe overall incidence of unplanned hospital admission after surgery at a large tertiary care ambulatory surgery center is very low. This admission rate can also serve as a reference point for future studies and quality improvement initiatives.

In silico and in vitro screening of selected antimicrobial compounds for inhibiting drug efflux pumps to combat threatening MRSA

The rapid emergence of antibiotic-resistant bacteria is occurring worldwide due to severe antibiotic abuse in the past few decades; among them, Methicillin-resistant Staphylococcus aureus (MRSA) is of major concern. Study examines potent antimicrobial compounds against Methicillin resistance Staphylococcus aureus (MRSA) efflux system. Interactome data serves as a primary focal point for global MRSA infection control initiatives. We employed CB Dock and Discovery Studio for performing docking analysis on specific antimicrobial compounds against NorA, NorB, and NorG. Additionally, we conducted molecular dynamics simulations using myPresto. In vitro validation was done by agar-based EtBr cartwheel method to assess the efflux pump activity of MRSA. Out of the eight screened antimicrobial compounds, quercetin exhibited favorable binding energies. Subsequently, molecular dynamics simulations were conducted on quercetin complexes with NorA, NorB, and NorG. In vitro result revealed that the quercetin is active at concentration of 60 µg/ml ±10 against MRSA to inhibit efflux mechanisms. Quercetin demonstrated the most promising binding affinity with the efflux pumps and their regulators of MRSA, making it the prime candidate for use with antibiotics. In-vivo experiments must be performed to validate the in-silico and in vitro analysis.

CPR++: Object Localization via Single Coarse Point Supervision.

Point-based object localization (POL), which pursues high-performance object sensing under low-cost data annotation, has attracted increased attention. However, the point annotation mode inevitably introduces semantic variance due to the inconsistency of annotated points. Existing POL heavily rely on strict annotation rules, which are difficult to define and apply, to handle the problem. In this study, we propose coarse point refinement (CPR), which to our best knowledge is the first attempt to alleviate semantic variance from an algorithmic perspective. CPR reduces the semantic variance by selecting a semantic centre point in a neighbourhood region to replace the initial annotated point. Furthermore, We design a sampling region estimation module to dynamically compute a sampling region for each object and use a cascaded structure to achieve end-to-end optimization. We further integrate a variance regularization into the structure to concentrate the predicted scores, yielding CPR++. We observe that CPR++ can obtain scale information and further reduce the semantic variance in a global region, thus guaranteeing high-performance object localization. Extensive experiments on four challenging datasets validate the effectiveness of both CPR and CPR++. We hope our work can inspire more research on designing algorithms rather than annotation rules to address the semantic variance problem in POL.

How literary tourism changes the tourists’ “baggage”: a conceptual framework for the educational function of literary tourism

ABSTRACT This conceptual study aims to provide a framework for the educational function of literary tourism, a niche within cultural, heritage and media-related tourism, by focusing on the relationship between tourism and education. The conceptual framework, established through previous research on literary museums, literary festivals, and literary routes, demonstrates that literary tourism offers tourists experiential and transformative learning experiences. Literary tourism offerings not only influence tourists’ literary knowledge and practical skill levels but also provide awareness that can potentially transform their personal lives and alter perspectives. The gains individuals acquire through literary tourism highlight the necessity of emphasizing the educational function of literary tourism. This underscores the significance for literary sites, literary destinations, tour operators, educational institutions, and similar stakeholders to invest in promoting this educational function. The conceptual framework outlined in this study regarding the educational function of literary tourism can serve as a valuable reference point for literary tourism initiatives and research.

Moment-to-moment within-person associations between maternal autonomy support and child defeat predicting child behavioral adjustment.

This study examines mother-child mutual regulation processes during a challenging puzzle task as predictors of preschoolers' behavioral adjustment 6 months later in a Chinese sample (N = 101, 46 boys, Mage = 57.41 months, SD = 6.58). Mother-child mutual regulation was measured by the moment-to-moment bidirectional within-person associations between maternal autonomy support and child defeat (i.e., expression of frustration, incapacity to complete the task, or giving up). Children whose mother provided more autonomy support after increases of child defeat showed lower levels of externalizing problems 6 months later, and children who showed less defeat after increases of maternal autonomy support showed higher levels of prosocial behaviors 6 months later. These predictive effects were significant after controlling for child behavioral adjustment at the initial time point, and mean levels of mother's autonomy support and child's defeat throughout the task. The mutual regulation processes did not significantly predict child internalizing problems. The findings suggest that the coordinated mother-child mutual regulation patterns in real time may have positive implications for preschoolers' behavioral adjustment. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Study of the effect of macrogeometry of rubbing steel bodies at their point contact on the tribological characteristics of lubricants under boundary lubrication conditions

The effect of the shape of contacting nonconformal elements of friction units that form an initial point contact on the tribological characteristics of lubricants during friction in the boundary lubrication mode. Point contact of rubbing bodies is realized on four-ball friction machines when testing tribological characteristics of lubricants in accordance with Russian GOST 9490–75 and GOST 23.221–84 Standards.However, these tests are carried out with the friction of standard bearing balls and does not allow taking into account the impact of materials of rubbing bodies on the results of the experiment. Therefore, two alternative designs of mandrels were developed, which allow implementation of two friction schemes: «rotating ball clamped in the spindle of the machine – three roller face planes» and «rotating ball — three cylindrical rollers». The load on the friction unit for both friction schemes, as well as in parallel on the mandrel under testing, in which three balls are installed, is the same (108 N), the spindle rotation speed is equal to 1 rpm, duration of testing is 60 min. The diameter of balls used in these experiments was 12.7 mm, and diameters of rollers were 5 and 8 mm, respectively. The material of samples was ShKh-15 tool steel or its 100Cr6 analogue. The designs of mandrels and the dimensions of samples were chosen in such a way that in all cases the contact areas of the experimental samples with the wearing (upper) ball would lie on a circle with a diameter of 7.32 mm. The tests were carried out under dry friction, and in boundary lubricated conditions in a PAO-4 polyalphaolefin oil medium, as well as in the same oil medium with the additives of oleic acid and DF-11 (a solution of zinc dialkyldithiophosphate in a low-viscosity oil). It is shown that the composition of a lubricating medium has a decisive effect on the test results (i.e., on the values of the friction coefficients and on the values of the areas of wear scars), while the geometry of the rubbing bodies, as well as the maximum Hertz stresses in the tribological contact, had a little effect on the antifriction and anti-wear characteristics of oils.

Analyzing Common Market Options in the Scope of OIC

This paper initially employs the gravity model in order to analyze the trade data of selected 23 OIC countries and its 4 different subgroups. Then it applies stochastic frontier analysis to the model to gain efficiency scores and uncapped trade potential among countries in order to determine whether the group would have trade creation effect once they go for a Common Market structure. According to the statistical results, the 23 country group gives statistically significant results while deriving a %62 uncapped trade potential among group countries. Additionally, the 13-country subgroup also gives statistically significant results while deriving a %59 uncapped trade potential among them.&#x0D; While there are a number of studies which applies stochastic frontier analysis to the gravity model and gains efficiency scores, this study is the first to employ the method for OIC countries in order to determine the best possible country group for a Common Market without having trade diversion affect. The purpose of this study is to determine the Common Market options for Turkiye in the scope OIC in order to be a reference point for future Common Market initiatives.

Modeling Shallow Landslide Runout Distance in Eocene Flysch Facies Using Empirical–Statistical Models (Western Black Sea Region of Türkiye)

Uncertainties related to runout distances in shallow landslide analyses may not only affect lives but may also result in economic losses. Owing to the increase in shallow landslides, which are especially triggered by heavy rainfall, runout distances have been investigated to decipher whether applications of a functional runout distance are feasible. This paper aims to give insights into the modeling of the shallow landslide runout probability in Eocene flysch facies in the Western Black Sea region of Türkiye. There are two main stages in this study—which are dominated by empirical models, the detection of initiation points, and propagation—which help us to understand and visualize the possible runout distances in the study area. Shallow landslide initiation point determination using machine learning has a critical role in the ordered tasks in this study. Modified Holmgren and simplified friction-limited model (SFLM) parameters were applied to provide a good approximation of runout distances during the propagation stage using Flow-R software. The empirical model parameters suggested for debris flows and shallow landslides were investigated comparatively. The runout distance models had approximately the same performance depending on the debris flow and shallow landslide parameters. While the impacted total runout areas for the debris flow parameters were predicted to amount to approximately 146 km2, the impacted total runout areas for the shallow landslide parameters were estimated to be about 101 km2. Considering the inclusion of the RCP 4.5 and RCP 8.5 precipitation scenarios in the analyses, this also shows that the shallow landslide and debris flow runout distance impact areas will decrease. The investigation of runout distance analyses and the inclusion of the RCP scenarios in the runout analyses are highly intriguing for landslide researchers.

Functional and multi-omics signatures of mitapivat efficacy upon activation of pyruvate kinase in red blood cells from patients with sickle cell disease.

Mitapivat, a pyruvate kinase activator, shows great potential as a sickle cell disease (SCD)-modifying therapy. The safety and efficacy of mitapivat as a long-term maintenance therapy are currently being evaluated in two open-label studies. Here we applied a comprehensive multi-omics approach to investigate the impact of activating pyruvate kinase on red blood cells (RBC) from 15 SCD patients. HbSS patients were enrolled in one of the open-label, extended studies (NCT04610866). Leukodepleted RBC obtained from fresh whole blood at baseline, prior to drug initiation, and at longitudinal timepoints over the course of the study were processed for multi-omics through a stepwise extraction of metabolites, lipids and proteins. Mitapivat therapy had significant effects on the metabolome, lipidome and proteome of SCD RBC. Mitapivat decreased 2,3-diphosphoglycerate levels, increased adenosine triphosphate levels, and improved hematologic and sickling parameters in patients with SCD. Agreement between omics measurements and clinical measurements confirmed the specificity of mitapivat on targeting late glycolysis, with glycolytic metabolites ranking as the top correlates to parameters of hemoglobin S oxygen affinity (p50) and sickling kinetics (t50) during treatment. Mitapivat markedly reduced levels of proteins of mitochondrial origin within 2 weeks of initiation of treatment, with minimal changes in reticulocyte counts. In the first 6 months of treatment there were also transient elevations of lysophosphatidylcholines and oxylipins with depletion of free fatty acids, suggestive of an effect on membrane lipid remodeling. Multi-omics analysis of RBC identified benefits for glycolysis, as well as activation of the Lands cycle.

Experimental and Simulation Studies of Imidazolium Chloride Ionic Liquids with Different Alkyl Chain Lengths for Viscosity Reductions in Heavy Crude Oil: The Effect on Asphaltene Dispersion.

Heavy crude oil poses challenges in terms of extraction and transportation due to its high viscosity. In the pursuit of effective methods to reduce viscosity in heavy crude oil, this study investigates the potential of imidazolium chloride ionic liquids with varying alkyl chain lengths as viscosity reducers. The experimental results demonstrate that the addition of 1-dodecyl-3-methylimidazole chloride ([C12-MIM]Cl) leads to a maximum viscosity reduction of 49.87%. Solubility parameters were calculated based on characterization of the average molecular structure of the asphaltenes. The viscosity reduction effect is enhanced when the solubility parameter of the ionic liquid closely matches that of the asphaltene. The initial asphaltene deposition point of heavy crude oil is increased from 63% to 68% with the addition of 150 mg/L [C12-MIM]Cl. Furthermore, the average particle size of asphaltene deposits decreases from 79.35 μm to 48.54 μm. The viscosity of heavy crude oil is influenced by the aggregation of asphaltenes. The ability of ionic liquids, especially those with longer alkyl chains, to disperse asphaltene molecules and reduce viscosity has been confirmed through molecular dynamics and quantum mechanical simulations.

Prediction of Effectiveness and Toxicities of Immune Checkpoint Inhibitors Using Real-World Patient Data.

Although immune checkpoint inhibitors (ICIs) have improved outcomes in certain patients with cancer, they can also cause life-threatening immunotoxicities. Predicting immunotoxicity risks alongside response could provide a personalized risk-benefit profile, inform therapeutic decision making, and improve clinical trial cohort selection. We aimed to build a machine learning (ML) framework using routine electronic health record (EHR) data to predict hepatitis, colitis, pneumonitis, and 1-year overall survival. Real-world EHR data of more than 2,200 patients treated with ICI through December 31, 2018, were used to develop predictive models. Using a prediction time point of ICI initiation, a 1-year prediction time window was applied to create binary labels for the four outcomes for each patient. Feature engineering involved aggregating laboratory measurements over appropriate time windows (60-365 days). Patients were randomly partitioned into training (80%) and test (20%) sets. Random forest classifiers were developed using a rigorous model development framework. The patient cohort had a median age of 63 years and was 61.8% male. Patients predominantly had melanoma (37.8%), lung cancer (27.3%), or genitourinary cancer (16.4%). They were treated with PD-1 (60.4%), PD-L1 (9.0%), and CTLA-4 (19.7%) ICIs. Our models demonstrate reasonably strong performance, with AUCs of 0.739, 0.729, 0.755, and 0.752 for the pneumonitis, hepatitis, colitis, and 1-year overall survival models, respectively. Each model relies on an outcome-specific feature set, though some features are shared among models. To our knowledge, this is the first ML solution that assesses individual ICI risk-benefit profiles based predominantly on routine structured EHR data. As such, use of our ML solution will not require additional data collection or documentation in the clinic.

Research on aircraft skin rivet detection technology based on the normal vector-density clustering algorithm.

Riveting quality is crucial to an aircraft's overall aerodynamic performance and fatigue life. In order to effectively extract the point cloud of rivet heads and analyze the quality of riveting, this paper proposes a rivet flushness detection method based on the normal vector-density clustering algorithm. First, initial point cloud data sampling is based on normal vectors. Then, the density clustering algorithm is employed to cluster and extract the point cloud of rivet heads. Subsequently, the obtained point cloud of rivet heads is subjected to the random sample consensus algorithm for fitting the contour and obtaining the model parameters of the rivet head. The paper introduces a quality detection metric to describe the flushness of the rivet head. Finally, the proposed method is applied to analyze the skin and theoretical model point cloud data of rivets. The results demonstrate that the proposed method yields small errors and high accuracy compared to theoretical values. The method is further employed for quality detection and analysis of rivet flushness in practical aircraft engineering. A visualization system for rivet flushness quality detection is developed to represent the results visually. This system enhances the intuitive identification of rivet detection outcomes. Therefore, the proposed method holds significant engineering application value in rivet flushness detection.

Spanish causatives

Spanish, contrary to Catalan, French and Italian, allows causees to appear in pre-infinitival position. This paper takes as initial point of departure the asymmetries between the pre-infinitival position vs. the post-infinitival discussed in Ordóñez and Saab (2017). I provide a cartographic account in which more than one site for causees must be posited. This proposal follows the same reasoning that posits more than one subject position in the clausal spine (see for instance Cardinaletti 2004). I characterize the higher pre-infinitival position as a criterial position in the sense of Rizzi (2006, 2007). Following that proposal, I address the question of the interaction of case in this higher causee projection. I adopt Baker and Vinokurova’s (2010) proposal that UG must allow two ways for case resolution: case via agreement and dependent case. I will show that Spanish spoken in Catalonia is uniform in its case assignment solution of dative case for causees. I propose that the higher causee projection is an applicative head which assigns dative uniformly. However, for Catalan, Italian and French and many other dialects of Spanish, case assignment depends on the transitivity of the infinitival verb. In these varieties I invoke dependent case.

Proteomic analysis of plasma proteins from patients with cardiac rupture after acute myocardial infarction using TMT-based quantitative proteomics approach

BackgroundCardiac rupture (CR) is a rare but catastrophic mechanical complication of acute myocardial infarction (AMI) that seriously threatens human health. However, the reliable biomarkers for clinical diagnosis and the underlying signaling pathways insights of CR has yet to be elucidated.MethodsIn the present study, a quantitative approach with tandem mass tag (TMT) labeling and liquid chromatography–tandem mass spectrometry was used to characterize the differential protein expression profiles of patients with CR. Plasma samples were collected from patients with CR (n = 37), patients with AMI (n = 47), and healthy controls (n = 47). Candidate proteins were selected for validation by multiple reaction monitoring (MRM) and enzyme-linked immunosorbent assay (ELISA).ResultsIn total, 1208 proteins were quantified and 958 differentially expressed proteins (DEPs) were identified. The difference in the expression levels of the DEPs was more noticeable between the CR and Con groups than between the AMI and Con groups. Bioinformatics analysis showed most of the DEPs to be involved in numerous crucial biological processes and signaling pathways, such as RNA transport, ribosome, proteasome, and protein processing in the endoplasmic reticulum, as well as necroptosis and leukocyte transendothelial migration, which might play essential roles in the complex pathological processes associated with CR. MRM analysis confirmed the accuracy of the proteomic analysis results. Four proteins i.e., C-reactive protein (CRP), heat shock protein beta-1 (HSPB1), vinculin (VINC) and growth/differentiation factor 15 (GDF15), were further validated via ELISA. By receiver operating characteristic (ROC) analysis, combinations of these four proteins distinguished CR patients from AMI patients with a high area under the curve (AUC) value (0.895, 95% CI, 0.802–0.988, p < 0.001).ConclusionsOur study highlights the value of comprehensive proteomic characterization for identifying plasma proteome changes in patients with CR. This pilot study could serve as a valid foundation and initiation point for elucidation of the mechanisms of CR, which might aid in identifying effective diagnostic biomarkers in the future.

Cooperative Coverage Path Planning for Multi-Mobile Robots Based on Improved K-Means Clustering and Deep Reinforcement Learning

With the increasing complexity of patrol tasks, the use of deep reinforcement learning for collaborative coverage path planning (CPP) of multi-mobile robots has become a new hotspot. Taking into account the complexity of environmental factors and operational limitations, such as terrain obstacles and the scope of the task area, in order to complete the CPP task better, this paper proposes an improved K-Means clustering algorithm to divide the multi-robot task area. The improved K-Means clustering algorithm improves the selection of the first initial clustering point, which makes the clustering process more reasonable and helps to distribute tasks more evenly. Simultaneously, it introduces deep reinforcement learning with a dueling network structure to better deal with terrain obstacles and improves the reward function to guide the coverage process. The simulation experiments have confirmed the advantages of this method in terms of balanced task assignment, improvement in strategy quality, and enhancement of coverage efficiency. It can reduce path duplication and omission while ensuring coverage quality.

The dynamics of impinging plumes from a moving source

We present the results from a series of experiments investigating the dynamics of gravity currents which form when a dense saline or particle-laden plume issuing from a moving source interacts with a horizontal surface. We define the dimensionless parameter $P$ as the ratio of the source speed, $u_a$ , to the buoyancy speed, $(B_0/z_0)^{1/3}$ , where $B_0$ and $z_0$ are the source buoyancy flux and height above the horizontal surface, respectively. Using our experimental data, we determine that the limiting case in which $P=P_c$ the gravity current only spreads downstream of the initial impact point occurs when $P_c=0.83\pm 0.02$ . For $P&lt; P_c$ , from our experiments we observe that the plume forms a gravity current that spreads out in all directions from the point of impact and the propagation of the gravity current is analogous to a classical constant-flux gravity current. For $P&gt;P_c$ , we observe that the descending plume is bent over and develops a pair of counter-rotating line vortices along the axis of the plume. The ensuing gravity current spreads out downstream of the source, normal to the motion of the source. Analogous processes occur with particle-laden plumes, but there is a second dimensionless parameter $S$ , the ratio of the particle fall speed, $v_s$ , to the vertical speed of a plume in a crossflow, $(B_0/u_a z_0)^{1/2}$ . For $S\ll 1$ , particles remain well mixed in the plume and a particle-driven gravity current develops. For $S\gg 1$ , particles separate from the plume prior to impacting the boundary which leads to a fall deposit and no gravity current. We discuss these results in the context of deep-sea mining.