bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulmonary Transit Time Assessment by CEUS in Healthy Rabbits: Feasibility, and the Effects of UCAs Dilution Concentration
Authors: Kang Song , Chen Jianfeng , Zhang He , Li Guangyin , Liu Yingying , Mei Xue , Zhu Binyang , Ai Xin , Jiang Shuangquan
Published: April 2024

To evaluate the inter-observer variability and the intra-observer repeatability of pulmonary transit time (PTT) measurement using contrast-enhanced ultrasound (CEUS) in healthy rabbits, and assess the effects of dilution concentration of ultrasound contrast agents (UCAs) on PTT. Thirteen healthy rabbits were selected, and five concentrations UCAs of 1:200, 1:100, 1:50, 1:10, and 1:1 were injected into the right ear vein. Five digital loops were obtained from the apical 4-chamber view. Four sonographers obtained PTT by plotting the TIC of right atrium (RA) and left atrium (LA) at two time points (T1 and T2). The frame counts of the first appearance of UCAs in RA and LA had excellent inter-observer agreement, with intra-class correlations (ICC) of 0.996, 0.988, respectively. The agreement of PTT among four observers was all good at five different concentrations, with an ICC of 0.758–0.873. The reproducibility of PTT obtained by four observers at T1 and T2 was performed well, with ICC of 0.888–0.961. The median inter-observer variability across 13 rabbits was 6.5% and the median variability within 14 days for 4 observers was 1.9%, 1.7%, 2.2%, 1.9%, respectively; The PTT of 13 healthy rabbits is 1.01 ± 0.18 second. The difference of PTT between five concentrations is statistically significant. The PTT obtained by a concentration of 1:200 and 1:100 were higher than that of 1:1, while there were no significantly differences in PTT of a concentration of 1:1, 1:10, and 1:50. PTT measured by CEUS in rabbits is feasible, with excellent inter-observer and intra-observer reliability and reproducibility, and dilution concentration of UCAs influences PTT results.
Conditioning on the Pre-Test versus Gain Score Modelling: Revisiting the Controversy in a Multilevel Setting
Authors: Arpino Bruno , Bacci Silvia , Grilli Leonardo , Guetto Raffaele , Rampichini Carla
Published: April 2024

We consider estimating the effect of a treatment on a given outcome measured on subjects tested both before and after treatment assignment in observational studies. A vast literature compares the competing approaches of modelling the post-test score conditionally on the pre-test score versus modelling the difference, namely, the gain score. Our contribution lies in analyzing the merits and drawbacks of two approaches in a multilevel setting. This is relevant in many fields, such as education, where students are nested within schools. The multilevel structure raises peculiar issues related to contextual effects and the distinction between individual-level and cluster-level treatments. We compare the two approaches through a simulation study. For individual-level treatments, our findings align with existing literature. However, for cluster-level treatments, the scenario is more complex, as the cluster mean of the pre-test score plays a key role. Its reliability crucially depends on the cluster size, leading to potentially unsatisfactory estimators with small clusters.
Mapping the Geographic Inequalities in Psychiatrist Distribution across Madhya Pradesh, India: An Exploratory Study
Authors: Sutar Roshan , Pakhare Abhijit , Lahiri Anuja , Sabde Yogesh , Singh Vijender
Published: April 2024

Objective:

The National Mental Health Survey identified a vast treatment gap across India. This treatment gap is partly attributed to the availability and accessibility of mental health services in different states. Accessibility to a psychiatrist in Madhya Pradesh (MP) is essential due to the significant disparity among urban, rural, and tribal regions across the state. The study attempted to identify the geographical disparity of psychiatrists in MP to improve future mental health service delivery.

Methods:

An online survey of practicing psychiatrists was conducted in December 2022 in the settings of public and private healthcare service delivery systems through offline and online accessibility/availability of psychiatrists practicing in MP, and the data were mapped using geo-locations of psychiatrists and were analyzed using ArcMap 10.8.1.

Results:

In total, 152 psychiatrists were practicing in MP across 195 locations, which amounts to 0.21 psychiatrists per 100,000 population with a concentration around big cities. Out of 54 districts, 24 districts did not have any practicing psychiatrists. A total of 155 health facilities were identified across 30 (55.6%) districts where at least one psychiatrist provided mental health services. The nearest-neighbor index for 152 points was –13.69.

Conclusions:

Combining psychiatrist geo-mapping data with population data comprehensively explains the MP state’s mental health service delivery needs. It could be wise to improve the spatial distribution of psychiatrists in each district rather than achieving the recommended ratio of doctors to patients per state. These data need to be supplemented with qualitative inquiry to help policymakers and health planners generate effective public–private partnerships in mental health service delivery in the coming time.
Microstructure and property evolution during tempering of a medium carbon bainitic steel
Authors: Mandal Sumanta , Ghosh Pampa , Rajput Ajeet Singh , Yadav Sonu , Haldar Arunansu
Published: April 2024

Tempering a medium carbon carbide-free bainite steel led to two distinct microstructures and properties below and above the bainitic start (Bs) temperature. Austenite decomposition during tempering, depended on carbon content, tempering temperatures and time, determining retained austenite (RA) stability. Up to 400 °C, most RA remained intact, but a significant reduction occurred above the Bs temperature. Film austenite primarily turned into carbides within the bainitic–ferrite matrix and form lines of carbide particles, while blocky austenite decomposed into troostite at 500 °C and sorbite at 600 °C. During tempering, on the other hand, bainitic ferrite lost tetragonality losing its carbon and resulting in the growth of bainitic–ferrite plates through grain boundary migration and misorientation annihilation. Above Bs, drastic microstructural changes caused significant alterations in tensile properties.
MUN-FRL: A Visual-Inertial-LiDAR Dataset for Aerial Autonomous Navigation and Mapping
Authors: Thalagala Ravindu G , De Silva Oscar , Jayasiri Awantha , Gubbels Arthur , Mann George KI , Gosine Raymond G
Published: April 2024

This paper presents a unique outdoor aerial visual-inertial-LiDAR dataset captured using a multi-sensor payload to promote the global navigation satellite system (GNSS)-denied navigation research. The dataset features flight distances ranging from 300 m to 5 km, collected using a DJI-M600 hexacopter drone and the National Research Council (NRC) Bell412 Advanced Systems Research Aircraft (ASRA). The dataset consists of hardware-synchronized monocular images, inertial measurement unit (IMU) measurements, 3D light detection and ranging (LiDAR) point-clouds, and high-precision real-time kinematic (RTK)-GNSS based ground truth. Nine data sequences were collected as robot operating system (ROS) bags over 100 mins of outdoor environment footage ranging from urban areas, highways, airports, hillsides, prairies, and waterfronts. The dataset was collected to facilitate the development of visual-inertial-LiDAR odometry and mapping algorithms, visual-inertial navigation algorithms, object detection, segmentation, and landing zone detection algorithms based on real-world drone and full-scale helicopter data. All the data sequences contain raw sensor measurements, hardware timestamps, and spatio-temporally aligned ground truth. The intrinsic and extrinsic calibrations of the sensors are also provided, along with raw calibration datasets. A performance summary of state-of-the-art methods applied on the data sequences is also provided.
Response to lorlatinib rechallenge in a case of ALK-rearranged metastatic NSCLC with a resistance mutation to second generation TKIs
Authors: Leporati Rita , Miliziano Daniela , Beninato Teresa , Mazzeo Laura , Manglaviti Sara , Brambilla Marta , Occhipinti Mario , Prelaj Arsela , Proto Claudia , Lo Russo Giuseppe
Published: April 2024

Introduction:

Several anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) have been developed for the treatment of echinoderm microtubule-associated protein-like 4 (EML4)-ALK-rearranged non-small cell lung cancer (NSCLC), with the newer generation agents brigatinib, alectinib and lorlatinib showing prolonged responses. With the increasing number of target therapies available, the optimal sequence is yet to be defined, as resistance profiles may evolve over time and in response to sequential ALK inhibitors. Therefore, ALK-targeted strategies may be personalized based upon the presence of specific ALK resistance mutations.

Methods:

Here, we report on the case of a patient who has been treated with a sequence of three ALK TKIs after receiving diagnosis of ALK-rearranged metastatic NSCLC in 2015 and gained further benefit upon lorlatinib rechallenge after the acquisition of the G1202R resistance mutation to second generation TKIs.

Results and conclusion:

In this case, the first ALK resistance mutation detected after progression on first line TKI, the I1171N, is a common resistance mutation after alectinib and confers sensitivity to brigatinib, that the patient received afterwards with a long-term disease stability. The second ALK resistance mutation detected after a chemotherapy interval, the G1202R, is the most common resistance mutation after second generation ALK TKIs and has been associated with sensitivity to third generation TKIs, such as lorlatinib. This case of a patient with EML4-ALK-rearranged NSCLC shows that sequential treatment with next-generation ALK TKIs, including rechallenge, can induce profound remissions, even in heavily pretreated patients, and that ALK-targeted strategies may be personalized by considering the presence of distinct ALK resistance mutations.
The relationship between occupational therapists’ organizational commitment, perceived organizational support, and entrepreneurial orientations
Authors: Gündoğmuş Ezginur , Özata Değerli Medine Nur , Abaoğlu Hatice
Published: April 2024

Introduction:

Entrepreneurial orientation is a critical factor in the success of an organization and encourages higher performance. Individual entrepreneurial orientation can be influenced by organizational commitment and perceived organizational support. The study aimed to examine the relationship between occupational therapists’ organizational commitment, perceived organizational support levels, and their individual entrepreneurial orientation.

Method:

Using an online form, a cross-sectional survey study was conducted with 88 occupational therapists aged between 22 and 28. Occupational therapists completed a socio-demographic information form, the Organizational Commitment Scale, the Perceived Organizational Support Scale, and the Individual Entrepreneurial Orientation Scale. Data were analyzed using descriptive statistics and correlation analysis.

Results:

Significant positive correlations were found between occupational therapists’ individual entrepreneurial orientations and organizational commitment ( p = 0.015; r = 0.260) and perceived organizational support ( p = 0.045; r = 0.214).

Conclusion:

This study indicates that occupational therapists’ individual entrepreneurial orientation increases when their levels of organizational commitment and perceived organizational support increase. Therefore, organizations should strive to maintain high levels of organizational commitment and the support provided by the organization to enhance the entrepreneurial orientation of occupational therapists, which is important for their creativity and innovation.
Scalable Combinatorial Vertiport Placement Method for an Urban Air Mobility Commuting Service
Authors: Kotwicz Herniczek Mark T. , German Brian J.
Published: April 2024

Vertiport locations have a significant impact on the time savings provided by an urban air mobility (UAM) commuting service relative to ground transportation and, thereby, greatly affect the value proposition and demand for UAM commuting services. In this paper, we present a discrete combinatorial vertiport placement method with a flexible objective function capable of directly optimizing for commuting demand. Preprocessing and postprocessing formulations that effectively reduce problem size and increase solution quality are also described. Demand-maximizing vertiport placement results are provided for Atlanta, New York City, San Francisco, and Seattle. We also present results showing the sensitivity of potential commuting demand to number of vertiports, ticket price, and service delay. Additionally, results that illustrate the impact of limiting vertiport placement to locations with existing airport and helipad infrastructure are presented. Finally, vertiport placement results optimized using a capacitated profitability-maximization objective are outlined.
Assessing Recycled Binder Availability, Activity, and Contribution at Different Temperatures
Authors: Costa Rafaella , Castorena Cassie
Published: April 2024

Recycled binder availability (RBA), degree of activity (DoA), and recycled binder contribution (RBC) are distinct properties often used interchangeably in the literature. This study aims to clarify the distinctions among these terms and assess how they vary with temperature, as well as their interrelationships. To achieve this, a reclaimed asphalt pavement (RAP) sieve analysis approach, indirect tensile strength testing of 100% RAP specimens, and tracer-based microscopy are employed to measure RBA, DoA, and RBC, respectively. Three RAP sources are evaluated, and each property is measured at multiple temperatures. Sieve analysis and microscopy measurements indicate that only partial RBA and RBC, respectively, are achieved, and that these properties display minimal susceptibility to changes in temperature. In contrast, DoA significantly increased as the temperature rose from 100°C to 140°C, reaching 100%, and then plateaued from 140°C to 155°C. In most of the cases, the laboratory-mixed asphalt mixture samples evaluated exhibited RBC values comparable to the RBA measurements for the respective RAP source, suggesting that RBC becomes equivalent to RBA when the DoA reaches 100%.
Numerical Research on Water Tightness of a New Type of Water Stopping Device at the Shield Machine Receiving Shaft
Authors: Lei Zhenyu , Wang Zhiqiang , Chen Zhengjie , Lu Ming
Published: April 2024

To meet the water stopping requirement of the shield machine receiving shaft, preliminary calculations are carried out on the structural design of a new type of water stopping device. The device is arranged on the inner arc surface of the embedded parts of the inner lining hole ring of the shield machine receiving shaft. By inflating the inflatable bag, the restriction of the limit bending steel plate is overcome, the flap is made to rotate to contact the shield machine shell to fill the gap between the shield machine and the hole ring, and waterproof materials are injected into the grouting pipe to stop leakage and water. For verifying the water stopping effect of the above structures and preparing for the later indoor model test, the numerical research work is mainly carried out on the standard section model. The nonlinear deformation process of the inflatable bag expansion and the contact with the embedded parts of the hole ring, the flap, and other components are analyzed, and the selection and bearing capacities of rubber materials are confirmed, so as to provide reference and guidance for the indoor model test. Combining the calculation results of different working conditions and the results of the indoor model pre-test, it is concluded that the stresses of each component do not exceed the corresponding allowable values, which indicates that the current design of the water stopping device is reasonable and feasible, and can be applied to test research.
Experimental tests and numerical simulation of delamination and fiber breakage in AP-PLY composite laminates
Authors: Zheng Weiling , Kassapoglou Christos
Published: April 2024

The behavior of delaminations and fiber breakage resulting from three-point bending test is a major concern in the study of composites. This research focused on analyzing fiber breakage and delaminations in advanced placed ply composite laminates through a series of tests. In order to compare simulation results with the experimental data, the cohesive zone model was implemented for analyzing the damage in the model. The results of the simulation were validated using experimental results. The predicted damage initiation load exhibited an approximate 20% deviation from the actual test loads and the discrepancy stems are analyzed.
Mechanical properties and design of hybrid composites of carbon and jute fibers with polypropylene
Authors: Li Zhigang , Wu Andi , Yang Jinghao , Wang Minghui , Deng Hai , Wang Chao
Published: April 2024

Natural fibers have both environmentally friendly and ecological advantages in the fiber material industry. Improving the mechanical properties and durability of natural fiber composites is an important research approach. As one of the representatives of synthetic fibers, carbon fiber has excellent mechanical properties and chemical stability, but its high cost and low toughness limit further application. Combining environmentally friendly, low-cost natural fibers with carbon fibers can broaden the development of natural fiber-reinforced composites in industrial applications. In this paper, the composites made of jute fibers and polypropylene (PP) as well as carbon fibers coupled with KH550 modification were prepared and their properties were investigated. By introducing a macroscopic model similar to the core-shell structure, an environmentally friendly material with better mechanical properties was achieved, with carbon fiber woven fabric serving as the shell and jute fiber mat as the core. The results show that a low-cost hybrid composite was successfully prepared by using a small amount of carbon fiber woven fabric instead of jute fiber mat, and the tensile, flexural and impact properties of the composites were improved by 488.27%, 70.75% and 463.39%, respectively, compared with those of the pure jute fibers composites. This study provides a rapid and reliable approach to improve the mechanical properties of the natural fiber composites.
Planners’ Changing Relationships With Participation: The Impact of New Training and Certification Schemes
Authors: Barry Janice , Novacevski Matt , Boyco Morgan , Legacy Crystal
Published: April 2024

Public participation is increasingly designed and facilitated by specially trained practitioners drawn from within the planning profession as well as outside of it. This shift is at least partially driven by the rise of new training and certification schemes. Drawing on exploratory interviews, and the example of the International Association for Public Participation in Canada and Australia, this paper highlights how these new forms of expertise are changing planners’ relationships with public participation. Our research reveals several points of tension, including a bifurcation between planning and public participation professionals along with a consolidation around narrowed ideas of public participation.
How Elites Invigorate Emotionality and Extremity in Digital Networks
Authors: Au Anson
Published: April 2024

The October 2017 Las Vegas shooting was the deadliest shooting in modern American history, but little scholarship has examined the public uproar in its wake, particularly in digital networks. Drawing on a corpus of 100,000 public Tweets and 1,119,638 unique words written in reaction to the shooting, this article addresses this lacuna by investigating the topics of reactions and their linkages with elites. This article theorizes that elites invigorate the emotionality of public reactions and broker the connection between discursive and affective content in digital networks. The results show that Tweets engaging with elites expressed statistically greater emotionality and extremity in emotional valences compared to Tweets written independent of elites. Additionally, this article identifies variations in the discursive themes invoked based on the types of elites. Mentions of non-political elites drew on themes about expressive support and depictions of the immediate environment with little emotional extremity. By contrast, mentions of political elites drew on themes about broader policy debates on gun ownership laws and adherent policy reforms. Unlike with non-political elites, mentions of political elites also exhibited greater extremity in negative emotional valences, reflective of increasing polarization in American politics.
Polyimides with ultra-low coefficient of thermal expansion derived from diamine containing bisbenzimidazole and bisamide
Authors: Fang Chuyi , Xu Ke , Li Tao , Qian Guangtao , Li Dandan , Chen Chunhai
Published: April 2024

To provide polyimide (PI) with high heat resistance and ultra-low coefficient of thermal expansion (CTE) for use in flexible display substrates, a novel diamine with bisbenzimidazole and bisamide groups, namely N,N'-(1H,1'H-[5,5'-bibenzo[d]imidazole]-2,2'-diyl)bis(4-aminobenzamide) (BZBA), was designed and successfully synthesized. Several poly(benzimidazole-amide-imide) (PBIAI) films were prepared by thermal imidization with 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic anhydride (ODPA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), and 4,4'-(hexafluoroisopropylindene)-diphthalic anhydride (6FDA), respectively. Among them, BZBA-BPDA has a high glass transition temperatures ( Tg = 345 °C) while achieving an extremely low coefficients of thermal expansion (CTE = 1.9 ppm K−1), meeting the processing requirements of polymer flexible substrates in OLED devices. The effects of different dianhydrides on the performance of PBIAIs were compared, providing a meaningful reference for further adjusting the PI molecular structure to meet specific requirements for industrial polymer films.
CL-FDAPF trajectory planner and FO-LADRC motion controller for autonomous sweeper vehicle
Authors: Zeng Dequan , Hu Yiming , Ai Tianfu , Liang Chengcheng , Yu Yiquan , Jiang Zhiqiang
Published: April 2024

Aiming at keeping safe in time and addressing disturbance of uncertainty, an closed loop forward simulation filtering double-layer artificial potential field (CL-FDAPF) trajectory planner and first order linear active disturbance rejective control (FO-LADRC) motion controller are proposed for autonomous sweeper vehicle. Firstly, the double-layer artificial potential field, which consists of traditional potential cost layer and safe level layer, is adopted here to keep planning realtime, meet safe limitations and satisfy operational requirements, and the postprocessing of mean filtering and closed loop forward simulation is for vehicle dynamic constraints. Secondly, it is worth developing active disturbance rejection control strategy, which has the ability to accommodate uncertainty, since an accurate mathematical model of autonomous sweeper vehicle is unavailable as there being inevitable uncertainties in the system state observation and unavoidable environmental disturbances. Thirdly, several typical scenarios are designed in order to verify the real-time and reliability of the proposed algorithm. The results illustrate that the CL-FDAPF planner has highly real-time and stability as the peak time less than 0.045 s and mean time being about 0.02 s in 1000 cycles, and FO-LADRC controller has robust both at uncertainty of wheelbase and steering ratio, since the FO-LADRC have smaller lateral errors compared with two existing methods.
A simple and robust parametric shared frailty model for recurrent events with the competing risk of death: An application to the Carvedilol Prospective Randomized Cumulative Survival trial
Authors: Sun Jiren , Cook Thomas
Published: April 2024

Many non-fatal events can be considered recurrent in that they can occur repeatedly over time, and some researchers may be interested in the trajectory and relative risk of non-fatal events. With the competing risk of death, the treatment effect on the mean number of recurrent events is non-identifiable since the observed mean is a function of both the recurrent event and terminal event processes. In this paper, we assume independence between the non-fatal and the terminal event process, conditional on the shared frailty, to fit a parametric model that recovers the trajectory of, and identifies the effect of treatment on, the non-fatal event process in the presence of the competing risk of death. Simulation studies are conducted to verify the reliability of our estimators. We illustrate the method and perform model diagnostics using the Carvedilol Prospective Randomized Cumulative Survival trial which involves heart-failure events.
The anthropocentrism thesis: (mis)interpreting environmental values in small-scale societies
Authors: Samways David
Published: April 2024

In both radical and mainstream environmental discourses, anthropocentrism (human centredness) is inextricably linked to modern industrial society's drive to control and dominate nature and the generation of our current environmental crisis. Such environmental discourses frequently argue for a retreat from anthropocentrism and the establishment of a harmonious relationship with nature, often invoking the supposed ecological harmony of indigenous peoples and/or other small-scale societies. In particular, the beliefs and values of these societies vis-à-vis their natural environment are taken to be instrumental in their low environmental impact. Here it is argued that, aside from the empirically problematic nature of such claims, the beliefs of small-scale societies have been seen through an ethnocentric discursive framework which bifurcates belief systems into anthropocentric and ecocentric. Taking a meta-theoretical approach informed by Strong Structuration Theory, it is argued that the beliefs of small-scale societies about their relationship with nature should be recognised as lying on a continuum of anthropocentrism and understood in the context of their attempts to establish ‘environmental ontological security’ in the face of natural uncertainty.
An Analysis of Healthcare Usage & Place of Death in England for All Adults Who Died in 2021/22
Authors: Wiltshire Justine , Grout Jacqueline , Krotosky Mike , Gerry Peter , Ashcroft Peter , White Rachel , Lillis Ash , Betteley Adrienne , Minton Ollie
Published: April 2024

Objective

We wanted to examine the healthcare use and non-elective activity in the UK population of expected deaths over an 1-year period to highlight and examine the reasons for variation. We did this to identify areas to focus interventions or resources on to reduce unnecessary emergency care use at the end of life.

Methods and Analysis

We assembled a data set of approximately 400 000 adults who died in England in the financial year 2021/22 (April 2021-March 2022). Any adults classified as a ‘sudden death’ were excluded. We used available data to ensure outcome measures were relevant used expert consensus to agree what to examine. We recorded place of death and examined urgent care in terms of admissions in the last year and 90 days of life. We also used recorded hospital care days as elective and non-elective usage.

Results

There were over 400 000 decedents included in our regression models. Close to half died in hospital (44%). Three-quarters (77%) had at least one day of unplanned hospital care in the 90 days before they died, and half (56%) had at least one day of planned hospital care.

Conclusion

Reliance on urgent care for those approaching end-of-life may indicate poor care planning and integration of services. A relatively modest increase in the amount of community care a person receives at end-of-life can substantially reduce the likelihood of dying in hospital. Those with a cancer cause of death are far less likely to die in hospital.
The Search for the Golden Ticket: A Value Chain and VRIO Experiential Exercise
Authors: Galloway Tera L.
Published: April 2024

While the benefits of experiential learning are well established throughout management and business courses, they are used less often when teaching strategic management. Yet, many concepts in strategy, such as the value chain, are difficult for students to understand. The abstract nature of these topics, coupled with the limited real-life exposure to strategy, make these topics difficult for students to understand and apply. The Golden Ticket exercise is designed to help students correctly apply the VRIO framework and conduct a value chain analysis. This exercise uses redirection as a learning tool, incorporating several independent myopic parts to create ambiguity, where students are initially unable to see how the exercise connects to the “big picture.” It is not until the end of the exercise that students can see how these parts connect (creating the big picture perspective), as they are able to identify the firm’s value creating activities, core competencies, and create the value chain for the firm. This exercise can be used in undergraduate and graduate-level strategy, marketing, and management classes, and can be taught face-to-face or online. Student feedback suggests that this exercise is engaging, practical, and an enlightening way to learn about value chain analysis and core competencies.
Enhancing Make-to-Order Manufacturing Agility: When Flexible Capacity Meets Dynamic Pricing
Authors: Sun Xu , Chai Shiwei , Paul Anand , Zhu Lingjiong
Published: April 2024

The rise of online marketplaces has raised customer expectations regarding customization and lead time. It poses significant challenges to manufacturing firms and prompts a move from make-to-stock to a more flexible make-to-order system. Compared to make-to-stock settings, make-to-order systems cannot smooth fluctuations in demand using available stock. While viewing dynamic pricing as a useful strategy to balance supply with demand, many manufacturing firms can also create capacity flexibility. In that scenario, system costs could be cut by managing capacity and demand simultaneously. In this paper, we consider a make-to-order production environment with base and surge capacity as well as the ability to adjust product pricing. Our main focus is on operational decision-making, assuming that the base capacity and surge capacity are fixed, but activating the surge capacity incurs a setup cost. Initially, we propose a stochastic control model to reflect this complex decision problem. However, our initial model leads to an intractable dynamic programming problem. To overcome this, we convert the problem to a more tractable diffusion control problem. This approach helps to reveal the conditions under which utilizing flexible capacity is more advantageous than relying solely on fixed capacity. When flexible capacity is advantageous, we provide a solution to the diffusion control problem that can guide optimal capacity and price adjustments. We discover an interesting interplay between capacity adjustment and dynamic pricing. In particular, we find that the price, which aims at reducing congestion, may not monotonically increase with the congestion level when capacity adjustments incur a fixed cost.
Product Customization and Returns: The Moderating Role of National Culture
Authors: Hilafu Haileab , Letizia Paolo , Roma Paolo
Published: April 2024

Product customization enables consumers to tailor products to their individual preferences. One benefit of customization is its lower volume of returns. By customizing, consumers learn about their product preferences and develop a sense of attachment to the products they help “create.” As a result, they are less likely to return the purchased items. The effect of product customization on returns may depend on cultural traits of consumers, such as the extent to which they would avoid uncertainty or the degree to which they would feel “subordinate” to authority. Hence, this article studies how national culture moderates the negative relationship between customization and returns. Our investigation analyzes a unique dataset from a leading global luxury brand manufacturer that offers both standard and customized versions of a product across more than 20 countries. We find that the disparity in return rates between standard (higher rate) and customized products (lower rate) depends on the cultural dimensions originally introduced by Hofstede. This gap widens with masculinity and uncertainty avoidance but narrows with power distance and individualism. Therefore, multinational firms should weigh these aspects of national cultures when designing both customization and return policies.
Cost Optimization in Cloud Computing: Capacity Reservation for Intermittent Random Demand Surges
Authors: Chen Shi , Lei Junfei , Moinzadeh Kamran
Published: April 2024

The adoption of cloud computing has been accelerating over the last decade, while enterprise cloud users (“firms”) are struggling to manage their growing cloud expenditures in the face of intermittent digital demand surges caused by planned or random events. To deal with such challenges, a firm can employ reserved instances with the standard contract length (e.g., one year) to meet the stationary base demand, which we refer to as the base contracts, complemented by additional reserved instances with either standard or shorter contract lengths, which we refer to as the supplementary contracts, to cope with the demand surges. We first analyze a model whereby the surge and inter-surge durations are deterministic, demand magnitude is random, and cancellation of the reservations is allowed. We develop a capacity management plan for the firm including not only the optimal capacity levels, which follow a newsvendor-type solution, but also the optimal policy for managing the purchase, renewal, cancellation, or expiration of the supplementary contracts, which can be characterized as a two-threshold policy. Due to the complexity of the structure of the optimal policy, we also construct an effective heuristic policy by excluding the renewal option from the action space, which can be applied to a more general setting where the surge and inter-surge durations are random. We examine two model extensions: (1) when trades of reserved instances are allowed in a secondary marketplace; (2) when the firm does not have exact information about the distributions of the surge magnitude and duration while it can adjust the capacity levels as data unveils. Our analysis shows that the optimal policy for managing the supplementary contracts depends on the relative magnitude of the surge and inter-surge durations in relationship to the cancellation fee. Moreover, our numerical results show that cloud platforms that offer a secondary marketplace are more attractive to firms from a cost standpoint than those that allow cancellation only. The latter, without the secondary marketplace, however, can achieve parity with the former by offering a deeper discount rate for the reserved instances, thereby bypassing the cost of administering the secondary marketplace.
Patterns of Physical Activity of Adolescents With ADHD in the School Context: A Cross-Sectional Study for Clinical Practice
Authors: Prat Raquel , Puig-Ribera Anna , Pagerols Mireia , Español-Martín Gemma , Rivas Cristina , Autet Aurea , Tàpies Pere , Martín Ana C. , Casas Miquel , Bosch Rosa
Published: April 2024

Objectives:

To describe the daily Physical Activity (PA) patterns of adolescents with Attention-deficit/hyperactivity disorder (ADHD), to analyze the differences in terms of PA patterns between adolescents with ADHD and those without ADHD, and to study the factors associated with achieving the daily PA recommendations.

Methods:

The sample was composed of 778 adolescents who provided complete information on their PA patterns through the Physical Activity Questionnaire for Adolescents (PAQ-A). Of these, 97 had ADHD according to DSM-5 criteria.

Results:

The results show that being a girl or being of foreign origin and having ADHD have an impact on the achievement of the recommended amount of daily PA.

Conclusions:

When promoting PA in adolescents with ADHD within the school environment, it is necessary to consider different domains and specific contexts of a school day, paying special attention to girls and adolescents with ADHD of immigrant origin.
Refractive changes associated with oculoplastic surgeries: A scoping review
Authors: Francisco Zamorano-Martín , Carlos Rocha-de-Lossada , Santiago Ortiz-Pérez , Rahul Rachwani-Anil , Jose-Luis Tovilla-Canales , Joaquín Fernández
Published: April 2024

Purpose

To carry out a comprehensive critical review of the peer-reviewed literature on the refractive changes associated with oculoplastic surgeries.

Methods

This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) statement recommendations. Following specific inclusion and exclusion criteria, 20 articles were selected for the current scoping review. Each of them was analyzed carefully and their risk of bias was assessed with the Quality Assessment Tool for case Series Studies from the National Heart, Lung and Blood Institute.

Results

Data of 1428 eyes from 1051 patients were analyzed. All studies were case series. Regarding the oculoplastic pathologies, five articles focused on dermatochalasis, four on chalazion, five on ptosis and six on congenital ptosis. Most articles did not report changes in the spherical equivalent (SE), astigmatism changes of less than 0.5 diopters (D), changes in astigmatism axis of less than 11 degrees and changes in uncorrected distance visual acuity (UDVA) of less than 0.06 logMAR. Out of the 20 articles reviewed, 6 achieved a risk of bias score between 6 and 8, representing a low level of evidence and highlighting the limitations in the study design.

Conclusions

Based on the findings of this study, there is no evidence to suggest clinically significant refractive changes following oculoplastic surgeries. The most notable changes may occur after surgery for severe ptosis; however, further research is needed to confirm this observation.
Levels and Health Risk Assessments of Heavy Metals in Khat and Its Support Soil in Algesachi, Ilu Ababor, Ethiopia
Authors: Damana Shibiru , Geletu Abiyot Kelecha , Keru Ibrahim Umer
Published: April 2024

Background:

Khat ( Catha edulis Forsk) is a stimulant plant grown in East Africa and the Arabian Peninsula. Heavy metal pollution has been a global concern due to its acute and chronic health effects and the major route of exposure is the consumption of contaminated foods. In this study, the determination and health risk assessment of heavy metals (Mn, Cu, Zn, Ni, Cr, Cd, and Pb) in khat and its support soil samples was carried out.

Materials and Methods:

Khat and its support soil were analyzed for the levels of 7 toxic heavy metals by Atomic Absorption Spectrophotometer. Samples were randomly collected from 3 districts of khat farming kebeles and digested using mixture of strong acids.

Results:

The concentrations (mg/kg) of analytes in soil and khat samples were: Cu (6.78-35.80); Zn (24.30-199.02); Mn (7.59-1855.40); Ni (6.37-64.80); Cr (0.82-169.20); Cd (14.2-38.8), and Pb (ND). Among the analyzed heavy metals in soil, Mn was with the highest concentration, followed by Zn, Cr, Cu, Ni, and Cd while that of Zn was the maximum followed by Cu, Mn, and Cr in khat. The levels of Zn, Cr, and Cd in soil samples from all study sites and detected concentrations of Cr in khat samples exceeded the recommended FAO/WHO levels.

Conclusion:

The hazard index (HI) of metals in khat from study areas was less than 1 indicating a less likelihood of non-carcinogenic toxicological health effects. However, the presence of these toxic chemicals in soil and khat indicates product contamination and needs extensive further investigation involving other heavy metals.
Dynamic model of high-speed maglev train-guideway bridge system with a nonlinear suspension controller
Authors: Bu Xiumeng , Wang Lidong , Han Yan , Liu Hanyun , Hu Peng , Cai CS
Published: April 2024

To improve the anti-interference ability of maglev trains, a dynamic model of the high-speed maglev train with a nonlinear suspension controller for the guideway system is proposed in this paper. Based on the nonlinear characteristics of the magnetic suspension system, a nonlinear decoupling controller is designed using the feedback linearization theory. Then, a high-speed maglev train model is refined with a guideway coupling system, consisting of a maglev train simulated as a multi-body dynamics model with 537 degrees of freedom and a spatial finite element model of the guideway. Taking the Shanghai high-speed maglev train as an example, the correctness of the computational model is verified by comparing the modeling results with field measurement data, and the control effectiveness of the nonlinear controllers and the traditional PD controllers is compared considering different train speeds and disturbance forces. The results show that the suspension gap under the decoupling control is smaller than that under the PD control during the train operations. Under the same disturbance force, the decoupling control exhibits better control performance than the PD control. The variation amplitudes of the magnetic pole gaps are generally linearly related to the disturbance force.
A time-domain integration method with equivalent complex damping model based on viscoelastic material constitutive relation
Authors: Fan Jia , Wang Shuxia , Sun Panxu
Published: April 2024

The complex damping model is only applied in frequency-domain. Based on the constitutive relation of viscoelastic materials, a vibration equation is equivalent to the constitutive relation of complex damping theory and the frequency response function satisfying the causality constraint. Compared with the existing equivalent complex damping model, the proposed equivalent damping model can consider more natural frequencies. The calculation formulas of Gauss precise integral method and improvement constant average acceleration method are derived. By the equivalent complex damping, the seismic time-history response of the typical example could carry on the numerical calculation. Compared with the Gauss precise integral calculation results of complex damping vibration equation, some conclusions can be analyzed. The proposed two methods could avoid divergent phenomenon in the time-domain numerical solution of complex damping vibration equation. The time-domain integral method of equivalent complex damping theory is stable and convergent. The Gauss precise integral method has strong equivalence and big computational complexity. The improvement constant average acceleration method has weak equivalence and small computational complexity.
Ultrasonic non-destructive inspection method for glass fibre reinforcement polymer (GFRP) hull plates considering design and construction characteristics
Authors: Han Zhiqiang , Liu Yang , Wu Xiaohong , Oh Daekyun , Jang Jaewon
Published: April 2024

The design and construction characteristics, including glass fibre weight fraction ( Gc), number of single-ply layers, fabric combination, and fabrication quality, of glass fibre reinforcement polymer (GFRP) hull plates affect ultrasound propagation characteristics, such as ultrasonic velocity and attenuation, thereby influencing the accuracy of ultrasonic non-destructive test results. Therefore, this study is to propose a method to decrease the ultrasonic test errors of GFRP hull plate by using statistical method. The GFRP specimens with Gc of approximately 30–50 wt%, thicknesses of approximately 5–20 mm, and different fabric combinations were prepared using the hand lay-up method, considering the general design–construction characteristics. Further, an ultrasonic velocity decision method for ultrasonic inspection was proposed considering the GFRP hull design-construction characteristics, such as Gc and number of single-ply layers of hull plate by multiple linear regression method. The results show that the proposed method can reduce the thickness measurement error from approximately 20%–30% to 1%–2%, compared to an existing ultrasonic inspection method, only considering the Gc effect on ultrasonic velocity, which indicates that the proposed test method is suitable for practical applications.
Temporal light modulation: A phantom array visibility measure
Authors: Tan J , Miller NJ , Royer MP , Irvin L
Published: April 2024

At temporal light modulation (TLM) frequencies between 80 Hz and 20 000 Hz observers may perceive a series of repeated images called the phantom array effect (PAE) when they move their eyes in large saccades across a modulating light source or across a scene lit by the modulating light source. To date, there is no well-established measure for quantifying PAE visibility, but there is growing awareness of the need for one among design professionals and sensitive populations. This paper documents a new measure, the phantom array visibility measure (PAVM), which is based on the results of recent human factors experiments. The measure follows the mathematical underpinning used by the flicker visibility measure and the stroboscopic visibility measure, where the time-domain TLM waveform is converted into its Fourier frequency components; each component is evaluated through a threshold curve of modulation depth, then summed through an equation employing a Minkowski exponent. This scales the PAVM so that a value of 1 indicates a waveform at a threshold visibility in the conditions of the underlying experiment.
Using Electronic Health Record Data for Occupational Therapy Health Services Research: Invited Commentary
Authors: Cogan Alison M. , Roberts Pamela , Mallinson Trudy
Published: April 2024

Health services research (HSR) is a field of study that examines how social factors, financing systems, organizational structures and processes, health technologies, and personal behaviors affect access to health care, the quality and cost of health care, and health and well-being. HSR approaches can help build the occupational therapy evidence base, particularly in relation to population health. Data from electronic health record (EHR) systems provide a rich resource for applying HSR approaches to examine the value of occupational therapy services. Transparency about data preparation procedures is important for interpreting results. Based on our findings, we describe a six-step cleaning protocol for preparing EHR and billing data from an inpatient rehabilitation facility for research and provide recommendations for the field based on our experience. Using and reporting similar strategies across studies will improve efficiency and transparency, and facilitate comparability of results.