Measurement Science Research Articles

The Relationship between Administrative Empowerment of School Principals and Teachers' Job Performance in the South Al Batinah Governorate of the Sultanate of Oman

Abstract Abstract: This study aimed to determine the level of administrative empowerment of school principals and its relationship with teachers' job performance in the South Al Batinah Governorate of the Sultanate of Oman. The study employed a descriptive correlational approach, and the researchers developed a questionnaire to gather the information. The questionnaire was administered to a sample of 86 principals in the South Al Batinah Governorate. The study reached several findings, among which is that the level of administrative empowerment for school principals was generally high, and likewise, the level of professional performance for teachers was high. Furthermore, it found a positive correlation between the empowerment of School principals and the job performance of teachers. The study recommended increasing attention to the development of practical scientific measures for the administrative empowerment of school principals and the development of measures to assess the level of teachers' job performance, as well as conducting further studies in this field.

Exploration of Water Resource Protection and Utilization in Tibet from the Perspective of Ecological Civilization

Tibet, known as the “roof of the world” in China's southwest border region, is not only rich in water resources, but also regarded as an important national energy reserve base. However, on a global scale, Tibet is also one of the few places in the world that faces the challenge of water scarcity. In order to cope with this challenge, it is necessary to deeply understand and grasp the connotation, essential characteristics and basic requirements of the concept of ecological civilization, and on this basis, combined with the current situation of water resources in Tibet, analyze the existing problems and put forward improvement measures in the light of the concept of ecological civilization, to promote the sustainable development and management of water resources in Tibet. As one of the core elements of ecological civilization construction, the protection and rational utilization of water resources are directly related to the stability of the ecological environment and the sustainable development of human society. Therefore, it is necessary to curb water pollution from the source and strengthen the protection of water environment. In view of the shortage of water resources in Tibet, it is necessary to scientifically plan and manage water resources, rationally allocate water resources, and improve the efficiency of water resources utilization. At the same time, it is also necessary to use modern scientific and technological means, such as remote sensing technology and big data analysis, to carry out real-time monitoring and management of water resources in Tibet to better cope with the challenge of water shortage. Finally, it is necessary to adhere to the concept of harmonious coexistence between man and nature, respect nature, adapt to nature, and protect nature, in order to achieve the goal of harmonious coexistence between man and water, man and nature. In general, through the in-depth study of water resources in Tibet, we can better understand the connotation, essential characteristics and basic requirements of the concept of ecological civilization, so as to propose more scientific and reasonable improvement measures to promote the sustainable development and management of water resources in Tibet and to realize the harmonious coexistence between human beings and nature.

Gendered Gaps in the Adoption of Climate-Smart Agriculture in Africa and How to Overcome Them

In Africa, the agricultural sector contributes approximately 10–20% of the total anthropogenic greenhouse gas (GHG) emissions. It presents rapid growth as a result of rising food demand in Africa, which is being driven by population growth. Consequently, climate change can negatively affect crop yields and livestock production, thus threatening food security. This review highlights the existing gender gaps in African agriculture and discusses the drivers and barriers that maintain gender gaps in climate-smart agriculture (CSA) adoption in African countries. Moreover, the review offers a comprehensive roadmap for the essential measures required to facilitate the widespread uptake of CSA practices among female farmers. Several CSA practices were reported, such as agricultural practices, forest and cropland regeneration practices, water resources, and the use of weather and climate information services. The gender gap in the adoption of CSA practices was influenced by policy legislation, financial resources, social and cultural taboos, and technical determinants such as climate information access. To address this gender gap, scientific-outcome-based research should be used to address gender gaps among female small farmers. In conclusion, to overcome the gender gap in CSA adoption in Africa, this review recommends the use of a gender-responsive approach, the development of scientific research-driven measures, and the prioritization of gender equality in governments’ agendas in the context of climate change uncertainty.

Assessment of water conservation and water intensification level based on AHP-fuzzy comprehensive evaluation model

Scientific evaluation of water conservation and water intensification level is an important prerequisite for addressing water resource shortage. In the current research, there are problems of confusing evaluation indicator systems and unscientific evaluation results. The paper first constructed the evaluation indicator systems of water conservation and water intensification based on the different connotations of the two, and then evaluated the utilization level of the two respectively by using AHP-fuzzy comprehensive evaluation model. The results indicated that from 2010 to 2022, the level of water conservation and water intensification in Zhengzhou both showed an upward trend, but the conservation level was higher than that of intensification. Therefore, promoting water intensification is the key to realize scientific water use in Zhengzhou in the future. Improving conservation level should prioritize the improvement of agricultural and domestic water use, while enhancing intensification level should prioritize the improvement of comprehensive and ecological water use. Separate evaluation of the two is more conducive to identifying weaknesses in their respective processes. Thus, more targeted and scientific improvement measures can be taken to enhance the level of urban water resource development and utilization.

Characterization of VOCs emissions and associated health risks inherent to the packaging and printing industries in Shandong Province, China

Comprehensive volatile organic compounds (VOCs) emission control is imperative to decreasing occupational health risks and environmental impact of the packaging and printing industries. In this work, we investigated the VOCs emission characteristics and concentrations of individual contaminants generated by the packaging and printing industries, with regard to various categories, processes, and geographic regions. VOCs emissions, ozone formation potential (OFP), and associated health risks were assessed at 10 representative packaging and printing firms across several cities in Shandong Province, China. Plastic packaging enterprises had the greatest levels of unorganized VOCs emissions, consisting predominantly of oxygenated volatile organic compounds (OVOCs), followed by alkanes and halocarbons. From metal and paper packaging enterprises, OVOCs, alkanes, and aromatics were significant components of unorganized VOCs emissions. Aromatics, halocarbons, and OVOCs contributed significantly to OFP in workshops. The potential carcinogenic risk associated with VOCs in the packaging and printing industries was not significant. However, according to the findings in this study, the workshop environment may provide a comparatively elevated non-carcinogenic risk attributable to ethyl acetate, isopropanol, acrolein, 1,1,2-Trichloroethane, 1,2-Dichloropropane, and naphthalene exposure. In particular, the endocrine-disrupting and genetic toxic effects caused by benzene, toluene, styrene, and naphthalene should not be overlooked. Thus, it is essential to provide precedence to the working environment conditions of workshop laborers, while also undertaking scientific and systematic measures to mitigate the detrimental impacts of VOCs on the environment and human welfare.

Evolution of ambiguity tolerance research a scientometric and bibliometric analysis.

The present study conducts a retrospective bibliometric analysis to examine the quantifiable and qualitative evolution of the concept of tolerance to ambiguity (TA) over time. Additionally, a scientometric analysis using quantitative methods on scientific measurements and trends aims to profile and identify the concept, as well as its development in research themes. The relevance of this study is underscored by the growing interest and development of research on TA, particularly in fields like entrepreneurship where psychological factors are significant. The research includes highly relevant literature, such as Budner and Frenkel-Brunswick, which define TA as a predisposition to perceive ambiguous situations as desirable and as a personality variable centered on the emotional and perceptual domain, respectively. Data was obtained from the eight indices comprising the main Web of Science collection, covering research from 1975 to December 2022. A total of 378 articles were identified. The analysis reveals that scientific production peaked in 2022 with 45 articles. In terms of citations, 7,773 were found, with the highest concentration in 2022, totaling 1,203 citations. This indicates a significant increase in research interest and output related to TA. The study highlights the growing exploration of the concept of TA, emphasizing its importance across multiple disciplines in dealing with uncertainty. The research demonstrates that TA significantly influences decision-making and adaptability, highlighting its value in business and educational settings. By analyzing leading publications, authors, and research centers, the study shows the diversity of approaches to understanding TA, indicating a promising direction for future research.

The Darakbang Heresy? Measures, Gauges and Measurements of Heretical Doctrine: Heretics and Accusers are Equally Evil

This article ensures and emphasises that a doctrine's standard, authoritative gauge and objective measurement is heresy. This purpose is motivated by the serious danger of false doctrine and accusations. False doctrine and false accusation are evil and should not be tolerated. This is contrary to the teachings of the Bible. The first and foremost step is to conduct scientific research. This research uses a case study method, namely the accusations of heresy against several Christian religious colleges in Indonesia for collaborating with Darakbang in South Korea. Based on this case study method, it was found that there is no heresy in them based on standardised measures. No authorised institution can legally declare someone or some other institution heretical. The accusers not only do not have and use the standard biblical measure of universal doctrine but also do not have authority as a measure authorised to declare heresy. In addition, none of the writings and accusations were found to be based on scientific measurements (studies). This finding is important as a recommendation for academics to distinguish between false teachings and false accusations so that academics do not become ignorant, evil people who mislead or accuse heretics unscientifically.

Post Sales Service Strategies and Small and Medium Enterprises Performance in Ibadan, Oyo State, Nigeria

Post Sales Service Strategies play a vital role on the performance of Small and Medium Enterprises. Post Sales Service is an increasingly important part of the business sand is more complex than manufacturing product. Unlike product, it is not possible to produce services in advance and inventory this future consumption. Post Sales Service has become an essential factor for all organizations nowadays; organizations are merging several marketing mixes in different ways to enhance Customer Satisfaction and Loyalty. Organizations are trying to provide excellent Post Sales Service to Customers and using several techniques to retain Customers. Post Sales Service helps to produce remarkable revenue in almost every business field. This study sought to assess the role in which Post Sales Service Strategies play on the performance of Small and Medium Enterprises in Ibadan, Oyo State, Nigeria. A survey among SMEs owners in Oyo State found that Post Sales Service can become a key differentiator and a major profit source if it’s being managed and carried out appropriately among the Small business owner and their customer in order to boost their operational performance and as well standardize their relationship with the customers. The study is immensely in various ways to Small Business Owners, Management, Practitioners, and Policy Makers. To the Small Business owners in Nigeria, the study will provide a more reliable scientific measure on issues affecting Post Sales Service on the performance of Small and Medium Enterprises. The findings also revealed that Post Sales Services are very important in mitigating possible collapse of SMEs. There search thus, recommends that SMEs should ensure that Post Sales Service should be used as an integral part of product offering at the same value to every customer in order to increase and survive in their operational performance efficiently and effectively.

Prediction of Suitable Habitat of Alien Invasive Plant Ambrosia trifida in Northeast China under Various Climatic Scenarios

Ambrosia trifida is an invasive alien plant species, which has very high reproductive and environmental adaptability. Through strong resource acquisition ability and allelopathy, it could inhibit the growth and reproduction of surrounding plants and destroy the stability of an invasive ecosystem. It is very important to predict the change of suitable distribution area of A. trifida with climate change before implementing scientific control measures. Based on 106 A. trifida distribution data and 14 points of environmental data, the optimal parameter combination (RM = 0.1, FC = LQ) was obtained using the MaxEnt (version 3.4.1) model optimized by Kuenm package, and thus the potential suitable areas of A. trifida in Northeast China under three different climate scenarios (RCP2.6, RCP4.5, RCP8.5) with different emission intensities in the future (2050, 2070) were predicted. The changes of A. trifida suitable area in Northeast China under three climate scenarios were compared, and the relationship between the change of suitable area and emission intensity was analyzed. In general, the suitable area of A. trifida in Northeast China will expand gradually in the future, and the area of its highly suitable area will also increase with the increasing emission intensity, which is unfavorable to the control of A. trifida.

A pre-control method in safety risk management of metro construction

ABSTRACT With the rapid development of metro construction in China, construction safety accidents occur frequently due to the lack of effective safety risk controls. Continuously improving the level of safety risk pre-control has become a significant factor in the safety managements of metro construction. This paper presents a reasoning model for safety risk pre-control measures in metro construction using case-based reasoning. To establish the case database, a frame-based knowledge representation method is adopted based on the characteristics of metro construction safety accident cases. Additionally, a two-level retrieval strategy combining hierarchical retrieval and nearest-neighbor algorithms is used for case retrieval. Furthermore, a new approach, the cloud model, is proposed to determine the attribute weight of metro construction safety accidents. This approach addresses quantitative attributes with fuzziness and randomness. Finally, a specific metro station is taken as a case to validate the feasibility of the approach. The results showed that the case-based reasoning method enables engineers to quickly and effectively develop risk pre-control measures based on previous cases. In addition, the use of case-based reasoning in decision-making enhances knowledge sharing and reuse in the metro construction industry. This paper presents an effective reasoning approach for pre-control measure analysis in metro construction, allowing engineers to quickly and efficiently carry out scientific and reasonable pre-control measures from past cases.

Thermal image evaluation of crop diseases in the incubation period.

Early blight is one of the main diseases that causes serious pepper yield and quality reduction. The identification of the presymptomatic features during the incubation period is of great research significance, in that scientific prevention measures in the incubation period may effectively reduce the loss of peppers. The present study confirms the feasibility of the identification of presymptomatic features in pepper early blight by infrared thermography during the incubation period. The infrared thermal images of pepper blades were captured during the whole incubation period in our experiment. Evaluation parameters such as temperature uniformity (U) and the variation coefficient (C) were established by infrared thermal images for the blade temperature field. Evaluation parameters such as temperature uniformity U and variation coefficient C of pepper blades change during the time from being inoculated to significant morbidity. For cases of stabbing inoculation, there were no relatively obvious symptoms in visible light images until 96 h after inoculation, whereas some presymptomatic features appeared in infrared thermal images at 60 h after inoculation. Based on the uniformity changes (δU) and the variation coefficient changes (δC) in the temperature field distribution, the characteristic polynomial (CP)-GBDT model has been established by optimizing the gradient boosting decision tree (GBDT) model. Compared with the GBDT mode, the CP-GBDT model accuracy increased from 87.5% to 91.7% on the test set. Evaluation parameters such as temperature uniformity U and variation coefficient C can be used to effectively characterize the presymptomatic features of pepper early blight by infrared thermography during the incubation period. The results of the present study can provide a reference for the detection of crop diseases in the incubation period. © 2024 Society of Chemical Industry.

A comprehensive research on measurement and evaluation of intelligent meter reading systems

Based on the machine vision and artificial intelligence technologies, the reading and acquisition of meter values have become the mainstream technical solutions for real-time monitoring of production data in the current industrial field. At the same time, the number of intelligent instruments and meters is increasing, and the quality varies. There is a lack of scientifically measurement methods and quality trust for intelligent meter reading algorithms. To promote their reliable and widespread application in various fields, it is necessary to conduct in-depth research on the assessment system of artificial intelligence in intelligent meter reading systems. This paper comprehensively studies various aspects involved in the emerging measurement field of artificial intelligence evaluation at the current stage, providing scientific measurement and evaluation references for the quality trust of artificial intelligence in the field of meters.

The Hera Radio Science Experiment at Didymos

Hera represents the European Space Agency's inaugural planetary defense space mission and plays a pivotal role in the Asteroid Impact and Deflection Assessment international collaboration with NASA DART mission that performed the first asteroid deflection experiment using the kinetic impactor techniques. With the primary objective of conducting a detailed post-impact survey of the Didymos binary asteroid following the DART impact on its small moon called Dimorphos, Hera aims to comprehensively assess and characterize the feasibility of the kinetic impactor technique in asteroid deflection while conducting an in-depth investigation of the asteroid binary, including its physical and compositional properties as well as the effect of the impact on the surface and shape of Dimorphos. In this work, we describe the Hera radio science experiment, which will allow us to precisely estimate critical parameters, including the mass, which is required to determine the momentum enhancement resulting from the DART impact, mass distribution, rotational states, relative orbits, and dynamics of the asteroids Didymos and Dimorphos. Through a multi-arc covariance analysis, we present the achievable accuracy for these parameters, which consider the full expected asteroid phase and are based on ground radiometric, Hera optical images, and Hera to CubeSats InterSatellite Link radiometric measurements. The expected formal uncertainties for Didymos and Dimorphos GM are better than 0.01% and 0.1%, respectively, while their J2 formal uncertainties are better than 0.1% and 10%, respectively. Regarding their rotational state, the absolute spin pole orientations of the bodies can be recovered to better than 1°, and Dimorphos' spin rate to better than 10−3%. Dimorphos reconstructed relative orbit can be estimated at the sub-m level. Preliminary results, using a higher-fidelity dynamical model of the coupled motion between rotational and orbital dynamics, show uncertainties in the main parameters of interest that are comparable to those in standard radio science models. A first-order estimate of the expected uncertainty in the momentum transfer efficiency from DART's impact, obtainable with Hera, yields a value of about 0.25. This represents a significant improvement compared to current estimates. Overall, the retrieved values meet the Hera radio science requirements and goals, and remain valid under the condition that the system is determined to be in an excited but non-chaotic (or tumbling) state. The Hera radio science experiment will play an integral role in the exploration of the Didymos binary asteroid system and will provide unique scientific measurements, which, when combined with other observables such as optical images, altimetry measurements, and satellite-to-satellite tracking of the CubeSats, will support the mission's overarching goals in planetary defense and the deep understanding of binary asteroids.

Research on coupling optimization of carbon emissions and carbon leakage in international construction projects

Due to the rapid economic development of globalization and the intensification of economic and trade exchanges, cross-international and regional carbon emissions have become increasingly severe. Governments worldwide establish laws and regulations to protect their countries' environmental impact. Therefore, selecting robustness evaluation models and metrics is an urgent research topic. This article proves the reliability and scientific of the assessment data through literature coupling evaluation, multidisciplinary coupling mathematical model and international engineering case analysis. The innovation of this project's research lies in the comprehensive analysis of the complex coupling effects of various discrete data and uncertainty indicators on the research model across international projects and how to model and evaluate interactive effects accurately. This article provides scientific measurement standards and data support for governments worldwide to formulate carbon tariffs and carbon emission policies. Case analysis data shows that the carbon emission ratio of exporting and importing countries is 0.577:100; the carbon trading quota ratio is 32.50:100.

Determining geo-disaster chains probabilities and disaster mitigation mode: A meta-analytical perspective

In a harsh geological environment, different geo-disasters might co-occur or be in a chain sequence. Currently, existing research in related fields documents numerous instances of disaster chains and responses, which provided this study with important materials for determining disaster chains probability and summarized the disaster prevention and mitigation (DPM) mode. In this study, through the depth of the geo-disaster chains cases and the DPM cases, enabled a mitigation mode analysis summary. We take the case of geo-disaster chains as an example for this study, and represent 20 typical geo-disaster chains by data fusion and structuring of 139 geo-disaster chains cases.The probability assessment of geo-disaster chains is crucial for risk management and regional resilience. We introduced a Bayesian network (BN) model to describe the process of geo-disaster chains formation to map the structure and assess the joint probability of geo-disaster chains. The BN results showed that the longer the disaster chains length, the smaller the probability of the chains occurring. Among these, the probability of “Collapses-landslides-debris flows–barrier lakes–flash floods” is the lowest (0.069). Through sensitivity analysis, it is found that precipitation is the most sensitive factor in the development of geo-disaster. Interpretive structural modeling (ISM) is employed to examine the DPM index system across three key aspects: disaster emergency preparation, disaster response, and disaster recovery, and the conceptualized interaction among these components. ISM results showed that government policy intervention and scientific DPM measures can effectively reduce the losses caused by the development of geo-disaster chains. This research combined the occurrence process of the disaster chains with the disaster response process, and determined the entire chains of characterization from disaster understanding to disaster response, and helped reduce the vulnerabilities caused by disasters.

Enhanced imaging with binary circular Dammann Fresnel zone plate

We introduce a novel approach in optical engineering by combining Dammann gratings with binary Fresnel zone plates to create a unique hybrid optical element with enhanced energetic efficiency of its focal spots. Traditionally, binary Fresnel zone plates focus light at multiple points with varying intensities, while Dammann gratings are renowned for their efficient and uniform light splitting capabilities. Our innovation lies in merging these two elements and generating a binary circular Dammann (varying along the radial direction) Fresnel zone plate that concentrates most of the incident light into a small and desired number of focused points with equal intensities, rather than distributing light’s energy non-equally across multiple points. This novel design significantly enhances the efficiency and precision of light manipulation. It opens new possibilities in applications requiring high-intensity focal points, such as in advanced medical imaging and in accurate scientific measurements. By redefining the conventional roles of these optical elements, our research contributes an advancement to the field, paving the way for innovative solutions in various optical applications.

Role of Ozone Hole on Life on Earth and Countermeasures

The purpose of this paper is to investigate the protection of the ozone layer and the extensive effects of the hole diffusion on the life on Earth. First, the ozone layer is a layer in the atmosphere that absorbs ultraviolet radiation from the sun and protects life on earth from ultraviolet damage. UV radiation is destructive to living organisms and can cause health problems such as skin cancer, eye damage and even genetic mutations. Therefore, the existence and health of the ozone layer is directly related to the survival and health of organisms on Earth. Next, we will study the formation and diffusion of the ozone hole. The hole in the ozone layer is caused by the destruction of the ozone layer caused by human activities such as the release of chemicals such as chlorofluorocarbons (CFCS). When these destructive factors enter the atmosphere and are irradiated by ultraviolet light, they break down into active free radicals, which destroy ozone molecules. Over time, these destructive factors accumulate in the atmosphere, causing the ozone layer to gradually thin and eventually form the ozone hole. Finally, we will discuss in detail the effects of these ozone holes on life on Earth. The existence of the ozone hole allows ultraviolet radiation to reach the Earth's surface, posing a direct threat to living organisms. Studies have shown that UV radiation can cause problems such as stunted plant growth, death of Marine life, and skin damage to animals. In addition, ultraviolet light can accelerate the Earth's climate change, causing more extreme weather events, such as floods, droughts and storms, which will have a broader and far-reaching impact on Earth's life. Through the discussion in this paper, we can clearly understand the impact of the ozone hole diffusion on the earth's organisms. In order to protect our home and biodiversity, we must take active measures to reduce the damage of human activities to the atmosphere in order to maintain a healthy and stable ozone layer. This requires our global efforts to take scientific and effective measures to solve this problem. Only in this way can we ensure that life on Earth can continue to live healthy and safe on the blue planet.

UNDERSTANDING GROUNDWATER DEPLETION IN INDIA: ASSESSING RISK THRESHOLDS AND ANALYSING CAUSATIVE FACTORS

Although hidden below the Earth’s surface, groundwater makes up 99% of Earth’s liquid fresh water and plays an important role in the water cycle. Rivers, lakes and wetlands are surface manifestations of groundwater, exchanging flow with the groundwater reservoir that feeds them when they need water and takes some of their flow when surface water is in excess. Groundwater also controls many features on the Earth’s surface. The depth of the water table is partly responsible for different plant species occupying different positions along the slopes from hill to valley, as only the drought-tolerant plants can live on dry hillsides and water-tolerant plants live near streams. Dissolution of carbonate rocks by flowing groundwater creates caves and sinkholes. In desert environments, groundwater discharge forms oases, which provide habitats for animals and plants. Groundwater provides drinking water entirely or in part for as much as 50% of the global population and accounts for 43% of all water used for irrigation. Worldwide, 2.5 billion people depend solely on groundwater resources to satisfy their basic daily water needs. The Earth’s population of nearly 8 billion in 2020 is expected to reach 11 billion by 2100. Humans will have to learn to produce sufficient food without destroying the soil, water and climate. This has been called the greatest challenge humanity has faced. Sustainable management of groundwater is at the heart of the solution. Scientific understanding and proper management of groundwater is essential because groundwater can alleviate the problem if we seek its responsible use and replenishment. Modern scientific measurements show that many of the major aquifers (groundwater reservoirs) of the world are being depleted. Such depletion can lead to a decrease in stream flow, drying of springs or wetlands, loss of vegetation, water-level declines in wells, and land subsidence. Yet another threat to groundwater is pollution resulting from human activity, generating chemicals and wastes that have leaked into the subsurface. Pollution degrades the quality of groundwater and poses a threat to human and ecological health. As the human population grows, more demand will be placed on groundwater, a vast, but finite, resource. The need for understanding our groundwater systems and thoughtfully managing them within the constraints of the hydrologic cycle is greater than ever. In this paper, our primary objective is to examine the history of the water crisis in India, critical risk tipping points and delve into the analysis of how we arrived at the current state of groundwater depletion, exploring the specific conditions and factors that have led us here. Furthermore, we will project the trajectory of this situation and assess where we are headed. Most importantly, we will outline the vision for the future that we aim to craft, considering the well-being of the next generations and the sustainability of India's groundwater resources.

Cross-prediction-powered inference

While reliable data-driven decision-making hinges on high-quality labeled data, the acquisition of quality labels often involves laborious human annotations or slow and expensive scientific measurements. Machine learning is becoming an appealing alternative as sophisticated predictive techniques are being used to quickly and cheaply produce large amounts of predicted labels; e.g., predicted protein structures are used to supplement experimentally derived structures, predictions of socioeconomic indicators from satellite imagery are used to supplement accurate survey data, and so on. Since predictions are imperfect and potentially biased, this practice brings into question the validity of downstream inferences. We introduce cross-prediction: a method for valid inference powered by machine learning. With a small labeled dataset and a large unlabeled dataset, cross-prediction imputes the missing labels via machine learning and applies a form of debiasing to remedy the prediction inaccuracies. The resulting inferences achieve the desired error probability and are more powerful than those that only leverage the labeled data. Closely related is the recent proposal of prediction-powered inference [A. N. Angelopoulos, S. Bates, C. Fannjiang, M. I. Jordan, T. Zrnic, Science 382, 669-674 (2023)], which assumes that a good pretrained model is already available. We show that cross-prediction is consistently more powerful than an adaptation of prediction-powered inference in which a fraction of the labeled data is split off and used to train the model. Finally, we observe that cross-prediction gives more stable conclusions than its competitors; its CIs typically have significantly lower variability.

Glycaemic Effects of a 156-km Ultra-trail Race in Athletes: An Observational Field Study.

Ultra-trail running races pose appreciable physiological challenges, particularly for glucose metabolism. Previous studies that yielded divergent results only measured glycaemia at isolated times. We aimed to explore the impact of an ultra-endurance race on continuously measured glycaemia and to understand potential physiological mechanisms, as well as the consequences for performance and behavioural alertness. Fifty-five athletes (78% men, 43.7 ± 9.6years) ran a 156-km ultra-trail race (six 26-km laps, total elevation 6000m). Participants wore a masked continuous glucose monitoring sensor from the day before the race until 10days post-race. Blood was taken at rest, during refuelling stops after each lap, and after 24-h recovery. Running intensity (% heart rate reserve), performance (lap times), psychological stress, and behavioural alertness were explored. Linear mixed models and logistic regressions were carried out. No higher risk of hypo- or hyperglycaemia was observed during the exercise phases of the race (i.e. excluding stops for scientific measurements and refuelling) compared with resting values. Laps comprising a greater proportion of time spent at maximal aerobic intensity were nevertheless associated with more time > 180mg/dL (P = 0.021). A major risk of hyperglycaemia appeared during the 48-h post-race period compared with pre-race (P < 0.05), with 31.9% of the participants spending time with values > 180mg/dL during recovery versus 5.5% during resting. Changes in circulating insulin, cortisol, and free fatty acids followed profiles comparable with those usually observed during traditional aerobic exercise. However, creatine phosphokinase, and to a lesser extent lactate dehydrogenase, increased exponentially during the race (P < 0.001) and remained high at 24-h post-race (P < 0.001; respectively 43.6 and 1.8 times higher vs. resting). Glycaemic metrics did not influence physical performance or behavioural alertness. Ultra-endurance athletes were exposed to hyperglycaemia during the 48-h post-race period, possibly linked to muscle damage and inflammation. Strategies to mitigate muscle damage or subsequent inflammation before or after ultra-trail races could limit recovery hyperglycaemia and hence its related adverse health consequences. NCT05538442 2022-09-21 retrospectively registered.