bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study of online academic risk prediction based on neural network multivariate time series features
Authors: Wu Yang , Yu Mengping , Huang Huan , Hou Rui 
Published: August 2024

SummaryNeural networks are becoming increasingly widely used in various fields, especially for academic risk forecasts. Academic risk prediction is a hot topic in the field of big data in education that aims to identify and help students who experience great academic difficulties. In recent years, the use of machine learning algorithms and deep learning algorithms to achieve academic risk prediction has garnered increased attention and development. However, most of these studies use nontime series data as features for prediction, which are slightly insufficient in terms of timeliness. Therefore, this article focuses on time series data features that are more expressive of changes in students' learning status and uses multivariate time series data as predictive features. This article proposes a method based on multivariate time series features and a neural network to predict academic risk. The method includes three steps: first, the multivariate time series feature is extracted from the interaction records of the students' online learning platforms; second, the multivariate time series feature transformation model ROCKET is applied to convert the multivariate time series feature into a new feature; third, the new feature is converted into a final prediction result using a linear classification model. Comparative tests show that the proposed method has high effectiveness.
Enhancing damping of low‐frequency oscillations in power networks through energy storage system‐based controller
Authors: Kumar Rohit , Mohanty Soumya R. , Verma Mitresh Kumar 
Published: August 2024

SummaryMitigating inter‐area low‐frequency oscillations is a significant concern in multi‐machine power systems due to their adverse effects on system stability. These oscillations are intricately linked with power oscillations. So appropriate power modulation through the Battery Energy Storage System (BESS) can be an effective strategy for preserving system stability. In this paper, the maximal of all minimal residue indices under variations in power system operating conditions is utilized as the index for identifying the location for installation of the BESS, the damping control loop, and the feedback signal. A fixed‐structure scheme‐based wide‐area damping controller (WADC) is proposed for the BESS, providing sufficient damping of inter‐area oscillation modes. A modified IEEE 39‐bus system is simulated using a real‐time digital simulator as a test system in this work. The simulation results confirmed that the proposed WADC could effectively damp various inter‐area oscillation modes. Furthermore, it offers robust damping performance over contingencies associated with the system's various operating scenarios as well as the uncertainty associated with fixed and variable communication delays in the feedback signal of WADC and the integration of solar photovoltaic systems. Moreover, a comparative analysis of the proposed WADC is carried out with a BESS‐based wide‐area power system stabilizer, which is found to be more effective in mitigating system inter‐area oscillations.
A distributed coordinated control strategy for isolated AC microgrids based on consensus algorithm considering communication delay
Authors: Yan Chaofeng , Li Qirui , Zhang Xiaomeng , Han Yang , Yang Ping , Zalhaf Amr S. 
Published: August 2024

AbstractIn the multi‐paralleled converter microgrid system, the traditional hierarchical control strategy can eliminate the bus voltage amplitude and frequency deviation from the rated value. However, isolated AC microgrids may face extreme scenarios such as communication delays and interruptions in data transmission due to the use of low‐bandwidth communication (LBC) lines. Additionally, the inconsistent line impedance of each distributed generation (DG) unit may result in the inaccurate division of reactive power in multi‐paralleled converter systems, thus affecting system stability. To address these issues, this paper presents a distributed coordinated control strategy for isolated AC microgrids based on the consensus algorithm. The proposed strategy first replaces LBC lines with a filter to alleviate the effects of communication delays. A small‐signal model is established in its state space, and stability of the microgrid system under the proposed control strategy is verified through eigenvalue analysis. Furthermore, based on the above theoretical analysis, a consensus algorithm is introduced, and a distributed control strategy for isolated AC microgrids based on the consensus algorithm is proposed to solve the issue of inaccurate equalization of the system's reactive power. Finally, factors that influence the dynamic convergence performance of the consensus algorithm are analyzed through simulation in PLECS software. Also, the maximum tolerable communication delays of the microgrid system under different communication topologies are also compared, and the system's robustness is evaluated under the condition of sudden communication interruption in a DG unit and sudden weather variation. These analyses confirmed the robustness of the proposed strategy against communication delays, output power fluctuation, and communication interruptions.
Substance Use and Its Relationship With Attachment and Early Maladaptive Schemes in Adolescents in Ecuador
Authors: Olave Leticia , Momeñe Janire , Macía Laura , Macía Patricia , Chávez‐Vera María Dolores , Herrero Marta , Estévez Ana , Iruarrizaga Itziar 
Published: August 2024

ABSTRACTGiven the scarcity of studies addressing substance consumption and its relationship with attachment styles and early maladaptive schemas in adolescents, the present study is proposed. Aims of this study are to analyze the relationship among attachment styles, early maladaptive schemas, and substance use; test the predictive role of attachment styles on substance use; and observe the mediating role of early maladaptive schemas in the relationship between attachment and substance use. The sample consisted of 1533 adolescents from Ecuador (53.9% males) aged between 14 and 18 years (M = 15.76; SD = 1.25). The attachment styles of security, value to parental authority, parental permissiveness, parental interference, self‐sufficiency and resentment against parents, childhood trauma, and family concern predict substance use (tobacco, alcohol, tranquilizers/sedatives or sleeping pills, hashish or marijuana, cocaine, GHB or liquid ecstasy, ecstasy, amphetamines/speed, hallucinogens, heroin, inhalants/volatiles), and the mediating role of early maladaptive schemas is confirmed (explained variance up to 33.33%). Identifying risk or vulnerability factors, such as attachment and early maladaptive schemas related to substance consumption, is especially relevant for designing and implementing preventive interventions in the adolescent population.
Heatwave‐induced functional shifts in zooplankton communities result in weaker top‐down control on phytoplankton
Authors: Huỳnh Thu‐Hương , Horváth Zsófia , Pálffy Károly , Kardos Vivien , Szabó Beáta , Dobosy Péter , Vad Csaba F. 
Published: August 2024

AbstractFreshwater ecosystems are increasingly affected by rising annual mean temperatures and heatwaves. While heatwaves are expected to have more immediate effects than mean temperature increases on local communities, comparative experimental studies are largely lacking. We conducted a 1‐month mesocosm experiment to test the effect of different warming treatments, constantly raised temperatures (+3°C) and recurring heatwaves (+6°C), on plankton communities. We specifically tested how shifts in zooplankton trait composition and functional groups are reflected in ecosystem function (top‐down control on primary producers). We found that heatwaves had a stronger and more immediate effect on zooplankton trait composition (specifically on body length and body mass) and functional groups. Heatwaves led to the decrease of small‐bodied grazers (i.e., Rotifera) and the dominance of larger omnivorous Copepoda, and these shifts resulted in weaker top‐down control, leading to elevated phytoplankton biomass. Altogether, our results highlight the importance of the indirect effects of heatwaves via inducing shifts in zooplankton functional groups and trait composition, which may lead to algal blooms.
Low‐intensity urbanisation alters community composition across multiple trophic levels on Lipsi Island, Greece
Authors: Hawkins Eleanor R. , Macrina Laura , Malcolm‐McKay Alice , Cotterill Nicola , Miliou Anastasia , O'Gorman Eoin J. 
Published: August 2024

AbstractUrbanisation has reduced the abundance and diversity of many taxonomic groups, and the effects may be more pronounced on islands, which have a smaller regional species pool to compensate. Green spaces within urban environments may help to safeguard wildlife assemblages, and the associated habitat heterogeneity can even increase species diversity. Here, total abundance and species diversity of butterflies, birds, and vegetation at nine rural and nine urban locations were quantified on Lipsi Island, Greece. Sites were assessed using Pollard walks for butterflies, point‐count surveys for birds, and quadrats for vegetation. There was no significant difference in the abundance or species diversity of butterflies or vegetation among rural and urban locations, which could pertain to the low building density within urbanised areas and the minimal extent of urbanisation on the island. However, urban areas hosted a significantly greater abundance, richness, and diversity of birds compared to rural sites. The community composition of butterflies, birds, and vegetation also differed significantly between urban and rural locations, highlighting the impact of urbanisation on species across a broad range of trophic groups. This study contributes to ecological knowledge on the impacts of urbanisation across multiple trophic levels in island ecosystems, with comparisons across a gradient of island size and urbanisation intensity needed in future research.
A comparison of the large‐scale gene expression patterns in summer and fall migratory Pantala flavescens (Fabricius) in northern China
Authors: Cao Lingzhen , Wang Na 
Published: August 2024

AbstractPantala flavescens (Fabricius) is the most well‐known seasonal migratory insect. This research focused on the molecular response of P. flavescens migration in summer and fall. A total of 17,810 assembled unigenes were obtained and 624 differentially expressed genes (DEGs) were identified in summer migration compared to fall migration. A number of DEGs, including cpr49Ae, itm2b, chitinase, cpr11B, laccase2, nd5, vtg2 and so on, had previously been reported to be involved in cold‐ and high‐temperature resistance. Functional enrichment analysis showed three pathways ‘that antibacterial humoral response, response to bacterial, and lipid transporter activity’ were significantly enriched in summer migration while that six pathways ‘structural constituent of cuticle, chitin binding, mitochondrion, propanoate metabolism, citrate cycle, hypertrophic cardiomyopathy’ were significantly enriched in fall migration. These results will provide a valuable baseline for further understanding of the molecular mechanisms of insect adaptation to different climate migrations.
Reduced trophic niche breadth is associated with higher productivity in a recovering apex predator population
Authors: de Gabriel Hernando Miguel , Fernández‐Gil Alberto , Lamas Javier A. , Ansola Luis M. , Román Jacinto , Revilla Eloy 
Published: August 2024

AbstractUnderstanding the trophic and demographic dynamics of apex predators is of paramount importance for ecosystem conservation. Apex predators are usually free from predation, and thus, the main driver of population dynamics is the availability of trophic resources, which affects breeding performance. Albeit food habits have been described in many apex species, the effects of changes in the trophic niche on long‐term demographic dynamics are poorly known. We describe the long‐term (N = 25 years) changes in trophic niche breadth of a recovering golden eagle population in a Mediterranean landscape (northern Spain) and search for potential correlates with their productivity (i.e., number of fledged eaglets per controlled pair) as a proxy for their breeding performance (N = 290 pair‐years). We identified a total of 3475 prey items from 77 species; rabbits, hares, and red‐legged partridges were the most frequent prey consumed (overall 51%), followed by roe deer (10%), red‐billed chough, red foxes, and woodpigeons, all of them with >5%. Prey diversity in eagles' diet decreased during the study period. Consumption of rabbits and roe deer increased, while that of hares and partridges decreased; no significant trends were observed in the consumption of foxes, choughs, and woodpigeons. Prey diversity and red‐legged partridge consumption were negatively correlated with productivity at the territory level, while rabbits, corvids, and pigeons showed a strong positive relationship with productivity. The size of the territory showed the strongest positive relationship with productivity, while roughness was negatively correlated. Rabbits and ungulates showed negative and positive correlations with roughness, respectively, while predator consumption exhibited a negative relationship with the size of the territory. Our findings give insights into the potential trophic mechanisms driving the dynamics of recovering apex predator populations; a reduction in the trophic niche breadth toward specific groups of prey, which could be due to a higher availability and individual specificity toward these prey species, might enhance productivity at the territory level and, ultimately, influence population dynamics facilitating the recovery process. The remarkable increase in the consumption of wild ungulates, predators, and other apex consumers suggests that the current population recovery and reduced trophic niche breadth may facilitate this eagle population to exhibit its apex role and contribute to ecosystem functionality.
Landscape, demographic, and dispersal parameters influence the spread and establishment of an aquatic biological invasion
Authors: MacDonald Kelly J. , Leroux Shawn J. , Purchase Craig F. 
Published: August 2024

AbstractHuman‐mediated species introductions are contributing to the biotic homogenization of global flora and fauna. Despite extensive research, we lack simple methods of predicting how and where an introduced species will spread and establish, particularly in species with complex life histories in aquatic ecosystems. We predict that spread can be modeled simply using the characteristics of the invading population, specifically species growth rate and dispersal capacity. In addition, we predict that the establishment of introduced species should be explained by the characteristics of the receiving ecosystem. Using the brown trout (Salmo trutta) invasion on the Island of Newfoundland as a case study, we fit and test a reaction–diffusion model with brown trout population data collected from the literature. Next, we use statistical models to assess the influence of a suite of abiotic (conductivity, pH, turbidity, calcium), biotic (Atlantic salmon occurrence), and landscape (watershed relief, watershed area, distance to original introduction) variables on brown trout establishment (i.e., presence–absence) patterns. We find that observed coastal spread in Newfoundland is slow (~4.4 km/year), and that it lies on the lower end of the range of predictions made by the reaction–diffusion model parameterized based on the estimates of growth rate and movement from the literature (predicted spread range 1.4 to 92 km/year). Also, we did not find evidence for a relationship between abiotic or biotic variables and brown trout establishment. However, we did observe that landscape variables of the distance to trout introduction point and estuary area may explain establishment patterns along the south coast of Newfoundland. Our results suggest the importance of using population‐specific parameterization and the need to integrate regional landscape factors that are generally applicable across biological invasions (e.g., distance to introduction), and those that are more specific to the ecology of the invader (e.g., estuary area). Our study contextualizes the mechanisms that contribute to a slow invasion by an aquatic species with a complex life history and reveals that future studies need to integrate a variety of methods to elucidate the processes governing invasions.
Natural coral recovery despite negative population growth
Authors: Mulla Aziz J. , Denis Vianney , Lin Che‐Hung , Fong Chia‐Ling , Shiu Jia‐Ho , Nozawa Yoko 
Published: August 2024

AbstractDemographic processes that ensure the recovery and resilience of marine populations are critical as climate change sends an increasing proportion on a trajectory of decline. Yet for some populations, recovery potential remains high. We conducted annual monitoring over 9 years (2012–2020) to assess the recovery of coral populations belonging to the genus Pocillopora. These populations experienced a catastrophic collapse following a severe typhoon in 2009. From the start of the monitoring period, high initial recruitment led to the establishment of a juvenile population that rapidly transitioned to sexually mature adults, which dominated the population within 6 years after the disturbance. As a result, coral cover increased from 1.1% to 20.2% during this time. To identify key demographic drivers of recovery and population growth rates (λ), we applied kernel‐resampled integral projection models (IPMs), constructing eight successive models to examine annual change. IPMs were able to capture reproductive traits as key demographic drivers over the initial 3 years, while individual growth was a continuous key demographic driver throughout the entire monitoring period. IPMs further detected a pulse of reproductive output subsequent to two further Category 5 typhoon events during the monitoring period, exemplifying key mechanisms of resilience for coral populations impacted by disturbance. Despite rapid recovery, (i.e., increased coral cover, individual colony growth, low mortality), IPMs estimated predominantly negative values of λ, indicating a declining population. Indeed, while λ translates to a change in the number of individuals, the recovery of coral populations can also be driven by an increase in the size of surviving colonies. Our results illustrate that accumulating long‐term data on historical dynamics and applying IPMs to extract demographic drivers are crucial for future predictions that are based on comprehensive and robust understandings of ecological change.
Development and validation of a multifactorial nomogram to predict 48 month mortality in decompensated heart failure
Authors: Zhuang Chenlin , Chen Yudai , Weng Kongyan , Zhuang Mei , Yu Huizhen , Zhu Pengli 
Published: August 2024

AbstractBackground and aimsAs the incidence of heart failure (HF) increases, the need for practical tools to evaluate the long‐term prognosis in these patients remains critical. Our study aimed to develop a 48 month prediction model for all‐cause mortality in decompensated HF patients using available clinical indicators.MethodsHF patients (n = 503), 60 years or older, were divided into a training cohort (n = 402) and a validation cohort (n = 101). Data on demographics, comorbidities, laboratory results and medications were gathered. Prediction models were developed using the Prognostic Nutritional Index (PNI), cholinesterase (ChE) and a multifactorial nomogram incorporating clinical variables. These models were constructed using the least absolute shrinkage and selection operator algorithm and multivariate logistic regression analysis. The performance of the model was assessed in terms of calibration, discrimination and clinical utility.ResultsThe mean age was 77.11 ± 8.85 years, and 216 (42.9%) were female. The multifactorial nomogram included variables of ChE, lymphocyte count, albumin, serum creatinine and N‐terminal pro‐brain natriuretic peptide (all P < 0.05). In the training cohort, the nomogram's C‐index was 0.926 [95% confidence interval (CI) 0.896–0.950], outperforming the PNI indices at 0.883 and ChE at 0.804 (Z‐tests, P < 0.05). The C‐index in the validation cohort was 0.913 (Z‐tests, P < 0.05). Calibration and decision curve analysis confirmed model reliability, indicating a more significant net benefit than PNI and ChE alone.ConclusionsBoth the ChE‐ and PNI‐based prediction models effectively predict the long‐term prognosis in patients over 60 years of age with decompensated HF. The multifactorial nomogram model shows superior performance, improving clinical decision‐making and patient outcomes.
Heterometallic Uranyl Squarate Compounds with Transition Metal‐Bipyridine Bulky Cations as Structure Directing Components
Authors: Meng Liao , Zhang Xu , Huang Zhi‐wei , Liang Yuan‐yuan , Hu Kong‐qiu , Yu Ji‐pan , Wang Xin‐peng , Fujita Toyohisa , Shi Wei‐qun , Mei Lei 
Published: August 2024

AbstractHeterometallic actinide compounds with tailored components functions have attracted much attention, but their controllable synthesis is still challenging. In this work, using bulky transition metal‐bipyridine cations as structure directing components, we have successfully synthesized six novel heterometallic uranyl squarate compounds, 1–6 with different metal‐bipyridine units. A time‐dependent crystal transformation from 1 with triple interwoven structure to 2 with parallel stacked structure is observed within the observation period of one month and further characterized via single‐crystal X‐ray diffraction (SCXRD) and powder X‐ray diffraction (PXRD). Further evidences from a combination of several techniques including thermal analysis, variable‐temperature PXRD and variable‐temperature SCXRD demonstrate dehydration‐related lattice evolution of 1 on the basis of structural flexibility of 1, which could be the origin of above‐mentioned crystal transformation from 1 to 2. Furthermore, the effect of types of anions (NO3−, Cl−, and SO42−) on structural diversity of 1–6 is also discussed in detail, where the Cl− or NO3− ion coordinate to Cu2+ center in isostructural 3 and 4, while SO42− bonds to uranyl nodes in isostructural 5 and 6. This work provides a feasible method for the tailored synthesis of multicomponent actinide complexes by the involvement of bulky charge balance components.