Sciences Research Council Research Articles

Robustifying Conditional Portfolio Decisions via Optimal Transport

We propose a data-driven portfolio selection model that integrates side information, conditional estimation, and robustness using the framework of distributionally robust optimization. Conditioning on the observed side information, the portfolio manager solves an allocation problem that minimizes the worst-case conditional risk-return tradeoff, subject to all possible perturbations of the covariate-return probability distribution in an optimal transport ambiguity set. Despite the nonlinearity of the objective function in the probability measure, we show that the distributionally robust portfolio allocation with a side information problem can be reformulated as a finite-dimensional optimization problem. If portfolio decisions are made based on either the mean-variance or the mean-conditional value-at-risk criterion, the reformulation can be further simplified to second-order or semidefinite cone programs. Empirical studies in the U.S. equity market demonstrate the advantage of our integrative framework against other benchmarks. Funding: The material in this paper is based on work supported by the Air Force Office of Scientific Research [Award FA9550-20-1-0397]. Additional support is gratefully acknowledged from the National Science Foundation [Grants 1915967, 1820942, and 1838676], the Natural Sciences and Engineering Research Council of Canada [Grant RGPIN-2016-05208], and the China Merchant Bank. V. A. Nguyen gratefully acknowledges the generous support from the Chinese University of Hong Kong [Improvement on Competitiveness in Hiring New Faculties Funding Scheme] and the Chinese University of Hong Kong [Direct Grant 4055191]. S. Wang is partially supported by the National Natural Science Foundation of China [Grant 72371022]. Finally, this research was enabled in part by support provided by Compute Canada. Supplemental Material: The computer code and data that support the findings of this study and the online appendix are available within this article’s supplemental material at https://doi.org/10.1287/opre.2021.0243 .

Efficient Implementation of Interior-Point Methods for Quantum Relative Entropy

Quantum relative entropy (QRE) programming is a recently popular and challenging class of convex optimization problems with significant applications in quantum computing and quantum information theory. We are interested in modern interior-point (IP) methods based on optimal self-concordant barriers for the QRE cone. A range of theoretical and numerical challenges associated with such barrier functions and the QRE cones have hindered the scalability of IP methods. To address these challenges, we propose a series of numerical and linear algebraic techniques and heuristics aimed at enhancing the efficiency of gradient and Hessian computations for the self-concordant barrier function, solving linear systems, and performing matrix-vector products. We also introduce and deliberate about some interesting concepts related to QRE such as symmetric quantum relative entropy. We design a two-phase method for performing facial reduction that can significantly improve the performance of QRE programming. Our new techniques have been implemented in the latest version (DDS 2.2) of the software package Domain-Driven Solver (DDS). In addition to handling QRE constraints, DDS accepts any combination of several other conic and nonconic convex constraints. Our comprehensive numerical experiments encompass several parts, including (1) a comparison of DDS 2.2 with Hypatia for the nearest correlation matrix problem, (2) using DDS 2.2 for combining QRE constraints with various other constraint types, and (3) calculating the key rate for quantum key distribution (QKD) channels and presenting results for several QKD protocols. History: Accepted by Giacomo Nannicini, Area Editor for Quantum Computing and Operations Research. Accepted for Special Issue. Funding: This work was supported by the National Science Foundation [Grant CMMI-2347120] and Discovery Grants from the Natural Sciences and Engineering Research Council of Canada. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information ( https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2024.0570 ) as well as from the IJOC GitHub software repository ( https://github.com/INFORMSJoC/2024.0570 ). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/ .

Securities Markets in Which Some Investors Receive Information About Cash Flow Betas

We analyze a single-factor setting in which there is private information regarding cash flows as well as their betas. Private information about betas, together with market makers’ risk aversion and mean betas’ nonnegativity, implies a nonlinear price schedule whose stochastic slope covaries positively with order flow when the expected factor payoff is positive and vice versa. We predict a negative relation between the covariance and expected returns and an attenuation of the beta anomaly in asset returns after accounting for this relation. Empirical tests confirm these predictions. This paper was accepted by Lukas Schmid, finance. Funding: L. Yang acknowledges the Social Sciences and Humanities Research Council of Canada [Grant 435-2021-0040] and Bank of Canada Fellowship for financial support. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2022.02061 .

The Adoption and Applications of Earth Observations and Allied Geoinformation Systems for Environmental Management in Ghana

Earth Observations (EOs) and allied technologies were initially adopted and applied to inform sustainable environmental resource management in Ghana. This paper examines the initial adoption of EOs in the early 1990s and subsequent applications. It highlights the transformative potentials of EO technologies in addressing critical environmental issues while also identifying barriers to their widespread adoption and options for optimal up-scaling. Literature review, in-depth interview, and personal experiences of the author were analyzed. The initial optimism bias generated may have masked the need for establishing the necessary sustainability arrangements. The adoption of EOs was driven by the need to generate data to inform natural and environmental resource management in the mid-1990s. Initially, EOs facilities were established in public organizations, including the Council for Scientific and Industrial Research (CSIR), Survey Department, and the University of Ghana. Since then, EOs have been applied in various sectors for research and environmental resource management. Granted, there have been successes. Yet, challenges undermine the optimization and scaling-up of actual benefits. These include the misconceived technocentric view of EOs, which is a restricted domain for the technically initiated and map-making tool. Others, such as unfavourable organizational processes, unsustainable funding, and limitations in research and applications, have adversely contributed to suboptimal outcomes. Suboptimal institutionalization of EOs into management decisions has constrained EOs infrastructure acquisition, maintenance and data procurement. To sustainably enhance EOs applications in resource management, research, and governance, a shift from present misconceptions for effective mainstreaming and a leveraging of EOs as integral parts of decision-making processes are prerequisites. Decision-makers and management personnel should be educated on the relevance of EOs’ functionalities to the core strategies of environmental management.

Teaching poetry using Instagram: An international, interdisciplinary study with adolescents mobilizing literacy and the arts

Young people engage daily with various social media platforms to communicate with each other across the globe. Adolescents not only share text, but also use images and sound to express themselves on platforms such as Instagram and TikTok to provide access to user-created content. The recent emergence of InstaPoetry—poetry with images on Instagram—has been part of such communication and provides a good entry point into adolescents’ engagement with literature and the arts. Limited research exists, however, on how this literate practice, paired with virtual and in-person museum visits, influences young people’s self-expression. In this article, we offer ways of integrating and involving these dynamic dimensions into research projects based on four sites of inquiry located in Canada and Australia. Funded by the Social Sciences and Humanities Research Council, this research project provides concrete avenues to investigate teachers’ methods to foster adolescents’ engagement with literature and the arts (i.e., contextual design, procedures, environment) in (post) COVID-19 times.

Challenging Vavřička: Questioning Compatibility of the Mandatory Tetanus Vaccination with ECHR.

The compatibility of mandatory vaccinations with human rights has become a very current issue with the COVID-19 pandemic and the Vavřicka ruling by the European Court of Human Rights. This ruling has faced criticism for not conducting examinations related to disease and vaccines based on direct scientific evidence. In this analysis, an assessment will be made based on direct scientific evidence about tetanus and its vaccine. The prevailing reason for mandatory tetanus vaccination is to protect the health of the vaccinated individual. Competent adults have the right to refuse treatment. This rule also applies to preventive medical interventions, including tetanus vaccination. As a rule, parents are entitled to give consent for medical interventions on their children. If an immediate and serious threat permanently endangers the minor’s life, medical intervention can be carried out against the parents’ will. The limitation of parental autonomy is more disputed when the minor’s life is not immediately threatened. With respect to tetanus vaccination as a preventive medical intervention, it does not eliminate an immediate and serious risk of harm. As a result, interference with the parent’s discretion on tetanus vaccination as a preventive medical intervention should be evaluated for its compatibility with the current legal approach to medical interventions on minors and patient rights. Keywords: best interest, mandatory vaccination, preventive medical intervention, right to reject a medical intervention, vaccine refusal, tetanus Acknowledgments: Z.T. wrote Part II: Information on Tetanus, M.S.P. wrote the rest of the paper. Elif Akdag was involved in formatting the footnotes. Funding: The authors were leading and core researchers in the project named “GETTING READY FOR THE NEXT PAN- DEMIC: Questioning Vaccine Mandates over COVID-19 and Childhood Vaccinations.” This project was funded by a grant from The Scientific and Technological Research Council of Türkiye (Grant Number: 122K378) and Altinbas University (Grant Number: PB2021-HUKUK-1). Conflicts of Interest: none

A traditional ecological knowledge summit

A traditional ecological knowledge summit The Global Center for Climate Change and Transboundary Waters (GCTW) cohosts a Traditional Ecological Knowledge Summit (1), as Gail Krantzberg (2), Peter Czajkowski, Dawn Martin-Hill, Rohini Patel, Hiliary Monteith, and Drew Gronewold explain. The Global Center for Climate Change and Transboundary Waters (GCTW) integrates hydroclimate modeling, water quality forecasting, and community-engaged mixed methods that harmonize and propagate Traditional Ecological Knowledge (TEK), Indigenous Knowledge (IK), and Western Science (WS) into robust 21st-century transboundary water resources governance protocols. The U.S. National Science Foundation and the Canadian Social Science and Humanities Research Council fund the Center. It supports a multinational network of researchers that is designed to promote information sharing across borders.

The Evaluatıon Of Technıcal Unıversıtıes In Turkey In Accordance Wıth Tübitak Entrepreneurıal And Innovatıve Unıversıty Index

Educational institutions compete with each other with entrepreneurial and innovative steps, just like production enterprises operating in different sectors. The Scientific and Technical Research Council of Turkey (TÜBİTAK) has been evaluating universities on a total of twenty-three sub-dimensions under four dimensions in line with the Entrepreneurial and Innovative University Index (GYÜE) every year since 2012. It shares the top fifty universities in the ranking with the public. These universities include both state universities and foundation universities. Eight of the top fifty universities in the ranking are Technical Universities. Since technical universities can integrate into more university-industry collaborations, they can undertake innovative and entrepreneurial projects and create value. In this context, the aim of the study is; It is the evaluation and ranking of Technical Universities in line with TÜBİTAK-GYÜE. Method of the research; The criterion weights of the technical universities included in the TÜBITAK 2022 index were determined by the AHP method, and in this direction, the findings were obtained by using the PROMETHEE method. The study is also important in terms of determining the differences between technical universities and other universities in the context of the entrepreneurial and innovative university index and the reasons for these differences.

Epidemiology of periportal fibrosis and relevance of current Schistosoma mansoni infection within the context of repeated mass drug administration in rural Uganda: a population-based, cross-sectional study

WHO guidelines for schistosomiasis-related morbidity control and elimination rely on current infection as a proxy indicator for morbidity. We evaluated these guidelines within the context of repeated mass drug administration and periportal fibrosis attributable to chronic intestinal schistosomiasis. We examined 1442households randomly sampled from 38villages in Buliisa, Pakwach, and Mayuge districts of Uganda within the SchistoTrack cohort. Periportal fibrosis was diagnosed in 2834individuals aged 5-90years using ultrasound and image patterns C-F from the Niamey protocol. Schistosoma mansoni status and intensity were diagnosed by Kato-Katz microscopy and point-of-care circulating cathodic antigen tests. Schistosome infection, co-infections, and comorbidities were examined as exposures for periportal fibrosis. Multivariable logistic regressions were run with SEs clustered by household. Between Jan 6and Feb 3, 2022, 342 (12·1%) of 2834 participants were diagnosed with periportal fibrosis. ByKato-Katz microscopy, 1229 (43·4%) of 2834participants were infected. 1863 (65·7%) of 2834participants had trace positive point-of-care circulating cathodic antigen tests, which was higher than prevalence by Kato-Katz microscopy, and 1158 (40·9%) of 2834participants had trace negative point-of-care circulating cathodic antigen tests. Individual schistosome status, intensity, and prevalence of heavy intensity infections of less than 1% and less than 5% were not correlated with periportal fibrosis likelihood or village prevalence. Periportal fibrosis likelihood linearly increased with age from age 5 years to age 25years, non-linearly increased from age 26 years to age 45years, attenuated or remained unchanged from age 46 years to age 60years, and steadily decreased past 60years of age. History of liver diseases, HIV, and ultrasound-detected chronic hepatitis or early cirrhosis-like disease were associated with more than two-times increased periportal fibrosis likelihood. WHO guidelines reliant on current schistosome status and intensity are uninformative for identifying probable cases or communities with periportal fibrosis. History of HIV and underlying chronic hepatitis or early cirrhosis-like disease are risk factors that could be investigated for periportal fibrosis surveillance and management. NDPH Pump Priming Fund, Wellcome Trust, John Fell Fund, Robertson Foundation, and UK Research and Innovation Engineering and Physical Sciences Research Council.

Gender, Race, and Entrepreneurship: A Randomized Field Experiment on Venture Capitalists and Angels

We study gender and race in high-impact entrepreneurship using a tightly controlled randomized field experiment. We sent out 80,000 pitch emails introducing promising but fictitious start-ups to 28,000 venture capitalists and angels. Each email was sent by a fictitious entrepreneur with randomly assigned gender and race. Female entrepreneurs received 9% more interested replies than males pitching identical projects and Asians received 6% more than Whites. Our results suggest that investors do not discriminate against female or Asian entrepreneurs when evaluating unsolicited pitch emails and that future research on investor biases should focus on networks and in-person interactions. This paper was accepted by Tomasz Piskorski, finance. Funding: The grant is Social Sciences and Humanities Research Council of Canada Insight Development [Grant 430-2019-00306] “Gender and racial discrimination in venture capital” through the University of British Columbia. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2024.4990 .

Examining the effect of geopolitical risks on renewable energy consumption in OECD countries

As urgent actions are required to accelerate the transition to a more environmentally friendly energy sector and global economy, the rising geopolitical risks defined as any tensions that disrupt the peace of local and international relations pose greater uncertainty to the rapid renewable energy deployment in supporting the carbon-neutrality ambitions. Thus, this paper investigates the influence of geopolitical risks on renewable energy consumption in OECD countries over the period 1970–2022 to address potential estimation biases from ignoring recent events such as COVID-19 and the ongoing Russia-Ukraine war. The paper applies a system GMM to a cross-country panel dataset while controlling for per capita income, carbon dioxide (CO2) emissions, economic globalization, and natural resource rents to deal with all possible sources of endogeneity. The results show that geopolitical risks reduce the consumption of renewable energy, with a magnitude of 0.22 percentage points. In addition, CO2 emissions and natural resource rents adversely affect the amount of renewable energy consumption. However, economic growth and globalization promote the demand for renewable energy. Therefore, the empirical findings suggest that geopolitical risks play a crucial role in the consumption of renewable energy. Acknowledgement The financial support from Engineering and Physical Sciences Research Council (EPSRC) under the project EP/T022930/1 is gratefully acknowledged. Authors would like to thank Prof. David Reiner and the Editor for their constructive comments and suggestions.

Optimal Learning and Management of Threatened Species

Amid an unprecedented loss of biodiversity, a pressing issue is how to improve the efficiency of conservation with limited resources and information. Collecting data on species with a small population is costly and time consuming, and many high-stakes decisions need to be made based on limited data. We develop a partially observable Markov decision processes model with unknown parameters to jointly optimize the information collection and protection efforts for threatened species. The model takes into account uncertainties about the state, detectability, and dynamics of the species, and it adaptively adjusts the efforts of surveying and protection in real time. Although the standard formulation is intractable, we exploit the structure of ecological problems to identify a hybrid belief state in low dimensions, and we reformulate the stochastic dynamic program as a piecewise deterministic optimal control problem. This enables us to obtain structural insights into the optimal policy (some are in closed form) and find a near-optimal approximate policy with performance guarantee. In certain situations, areas where the species has never been found may be more likely to contain the species than areas where it has been previously found. We also conduct a case study on the conservation of the Hainan gibbon, the rarest primate species, in which we extend the model to optimize the spatiotemporal allocation of limited resources. This paper was accepted by Chung Piaw Teo, optimization. Funding: This work was supported by the Natural Sciences and Engineering Research Council of Canada [Grant RGPIN-2019-05671]. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2023.01753 .

Impact of being taken into out-of-home care: a longitudinal cohort study of First Nations and other child welfare agencies in Manitoba, Canada

Across Canada, Child Protection Services (CPS) disrupt Indigenous families by apprehending their children at alarmingly high rates. The harms borne by children in out-of-home care (OoHC) have been extensively documented. We examined the impact of OoHC on Manitoba children's health and legal system outcomes to provide rigorous evidence on how discretionary decision-making by CPS agencies can affect these outcomes. In partnership with First Nations researchers, we used linked administrative data to identify Manitoba children (born 2007-2018) served by First Nations and other Manitoba CPS agencies. We compared those taken into OoHC (n=19,324) with those never in care but with an open CPS file due to child protection concerns (n=27,290). We used instrumental variable analysis (CPS agency rates of OoHC as the instrument) to obtain odds ratios (aOR) and 95% confidence intervals adjusted for child, maternal, and family factors. Mean age (yrs±standard deviation) at first CPS contact for children taken into OoHC was 2.8±3.7 (First Nations) and 3.0±3.8 (other), and for children never in care was 4.5±4.5 (First Nations) and 5.1±4.7 (other). Among children served by a First Nations agency, males made up 50.6% (n=5496) in OoHC and 51.0% (n=6579) never in care. Among children served by other agencies, males made up 51.0% (n=4324) in OoHC and 51.0% (n=7428) never in care. Odds of teen pregnancy (First Nations aOR 3.69, 1.40-9.77; other aOR 5.10, 1.83-14.25), teen birth (First Nations aOR 3.23, 1.10-9.49; other aOR 5.06, 1.70-15.03), and sexually transmitted infections (other aOR 7.21, 3.63-14.32) were higher for children in care than children never in care, as were odds of being accused (other aOR 2.71, 1.27-5.75), a victim (other aOR 1.68, 1.10-2.56), charged with a crime (other aOR 2.68, 1.21-5.96), or incarcerated (First Nations aOR 3.64, 1.95-6.80; other aOR 1.19, 1.19-8.04). Being in OoHC worsened children's health and legal system outcomes. The importance of reducing the number of children taken into care was emphasized in briefings to provincial and First Nations governments. The government response will be monitored. Social Sciences and Humanities Research Council (no. 890-2018-0029).

The Electric Vehicle Routing and Overnight Charging Scheduling Problem on a Multigraph

In the electric vehicle (EV) routing and overnight charging scheduling problem, a fleet of EVs must serve the demand of a set of customers with time windows. The problem consists in finding a set of minimum cost routes and determining an overnight EV charging schedule that ensures the routes’ feasibility. Because (i) travel time and energy consumption are conflicting resources, (ii) the overnight charging operations take considerable time, and (iii) the charging infrastructure at the depot is limited, we model the problem on a multigraph where each arc between two vertices represents a path with a different resource consumption trade-off. To solve the problem, we design a branch-price-and-cut algorithm that implements state-of-the-art techniques, including the ng-path relaxation, subset-row inequalities, and a specialized labeling algorithm. We report computational results showing that the method solves to optimality instances with up to 50 customers. We also present experiments evaluating the benefits of modeling the problem on a multigraph rather than on the more classical 1-graph representation. History: Accepted by Andra Lodi, Area Editor for Design and Analysis of Algorithms—Discrete. Funding: This work was supported by the Natural Sciences and Engineering Research Council of Canada through the Discovery grants [Grant RGPIN-2023-03791]. It was also partially funded by HEC Montréal through the research professorship on Clean Transportation Analytics. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information ( https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2023.0404 ) as well as from the IJOC GitHub software repository ( https://github.com/INFORMSJoC/2023.0404 ). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/ .

228 Physical literacy and inclusion within the context of disability and impairment: A multiple case study approach

Abstract Background and Purpose Physical literacy (PL) holds significant importance in various organizational agendas, being prioritized as a core programming priority under the premise of inclusivity irrespective of ability. However, there is a notable gap in understanding PL within the context of disability and impairment, as application of PL often occurs through a lens of normativity and standardization by those who do not experience disability. This study aims to establish an evidence-based, context-specific and foundational understanding of PL and its inclusivity of all individuals regardless of ability level, that can be utilized to inform, guide, and support current and future programs. Methods Employing the communities of practice theoretical model, a multiple case study design was utilized to delve into three purposefully selected cases rich in PL and inclusive practices. Data was collected through face-to-face, semi-structured interviews with stakeholders including participants, parents, practitioners, supervisors, and administrators. Supplemental data sources included direct observations, exploration of program documents, site photographs, and reflexive engagement. An inductive thematic analysis was conducted to uncover stakeholder perspectives, providing context-specific insights into PL as an inclusive concept. Findings Three overarching themes emerged, elucidating the foundations of PL as an inclusive concept: environmental considerations, operating with intention, and ethical and informed practice. These themes intersect with one another to foster opportunities for PL development across age and ability spectrums. Conclusions The findings offer evidence-based insights into PL and inclusion practices, offering a framework to move beyond normative and standardized notions of PL development. Support/Funding Source Government of Canada Social Sciences and Humanities Research Council Partnership Engage Grant (File No. 892-2021-1009).

Heatmap Design for Probabilistic Driver Repositioning in Crowdsourced Delivery

This paper proposes the use of heatmaps as a control lever to manage the probabilistic repositioning of independent drivers in crowdsourced delivery platforms. The platform aims to maximize order fulfillment by dynamically matching drivers and orders and selecting heatmaps that trigger the probabilistic flow of unmatched drivers to balance driver supply and delivery requests across the service region. We develop a Markov decision process (MDP) model to sequentially select matching and heatmap decisions in which the repositioning behavior of drivers is captured by a multinomial logit discrete choice model. Because of the curse of dimensionality and the endogenous uncertainty of driver repositioning, the MDP model is solved using a rolling-horizon stochastic lookahead policy. This policy decomposes matching and heatmap decisions into two optimization problems: a two-stage stochastic programming upper bounding problem for matching decisions and a mixed-integer programming problem for heatmap decisions. We also propose a simple policy for efficiently solving large-scale problems. An extensive computational study on instances derived from the Chicago ride-hailing data set is conducted. Computational experiments demonstrate the value of heatmaps in improving order fulfillment beyond the level achieved by matching alone (up to 25%) and identify conditions that affect the benefit of using heatmaps to guide driver repositioning. Funding: The authors gratefully acknowledge the support of the Natural Sciences and Engineering Research Council of Canada through Discovery Grants [Grants RGPIN-2024-04881, RGPIN-2020-04498, and RGPIN-2019-06207] awarded to the first, second, and third authors, respectively. Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2022.0418 .

Testicular mosaicism in non-mosaic postpubertal Klinefelter patients with focal spermatogenesis and in non-mosaic prepubertal Klinefelter boys.

Do testis-specific cells have a normal karyotype in non-mosaic postpubertal Klinefelter syndrome (KS) patients with focal spermatogenesis and in non-mosaic prepubertal KS boys? Spermatogonia have a 46, XY karyotype, and Sertoli cells surrounding these spermatogonia in postpubertal patients also have a 46, XY karyotype, whereas, in prepubertal KS boys, Sertoli cells surrounding the spermatogonia still have a 47, XXY karyotype. A significant proportion of patients with non-mosaic KS can have children by using assisted reproductive techniques thanks to focal spermatogenesis. However, the karyotype of the cells that are able to support focal spermatogenesis has not been revealed. Testicular biopsy samples from non-mosaic KS patients were included in the study. Karyotyping for sex chromosomes in testis-specific cells was performed by immunohistochemical analysis of inactive X (Xi) chromosome and/or fluorescent in situ hybridization (FISH) analysis of chromosomes 18, X, and Y. A total of 22 KS patients (17 postpubertal and 5 prepubertal) who were non-mosaic according to lymphocyte karyotype analysis, were included in the study. After tissue processing, paraffin embedding, and sectioning, the following primary antibodies were used for cell-specific analysis and Xi detection; one section was stained with MAGE A4 for spermatogonia, SOX9 for Sertoli cells, and H3K27me3 for Xi; the other one was stained with CYP17A1 for Leydig cells, ACTA2 for peritubular myoid cells, and H3K27me3 for Xi. Xi negative (Xi-) somatic cells (i.e. Sertoli cells, Leydig cells, and peritubular myoid cells) were evaluated as having the 46, XY karyotype; Xi positive (Xi+) somatic cells were evaluated as having the 47, XXY. FISH stain for chromosomes 18, X, and Y was performed on the same sections to investigate the karyotype of spermatogonia and to validate the immunohistochemistry results for somatic cells. According to our data, all spermatogonia in both postpubertal and prepubertal non-mosaic KS patients seem to have 46, XY karyotype. However, while the Sertoli cells surrounding spermatogonia in postpubertal samples also had a 46, XY karyotype, the Sertoli cells surrounding spermatogonia in prepubertal samples had a 47, XXY karyotype. In addition, while the Sertoli cells in some of the Sertoli cell-only tubules had 46, XY karyotype, the Sertoli cells in some of the other Sertoli cell-only tubules had 47, XXY karyotype in postpubertal samples. In contrast to the postpubertal samples, Sertoli cells in all tubules in the prepubertal samples had the 47, XXY karyotype. Our data also suggest that germ cells lose the extra X chromosome during embryonic, fetal, or neonatal life, while Sertoli cells lose it around puberty. Peritubular myoid cells and Leydig cells may also be mosaic in both postpubertal patients and prepubertal boys, but it requires further investigation. The number of prepubertal testicle samples containing spermatogonia is limited, so more samples are needed for a definitive conclusion. The fact that not all the cell nuclei coincide with the section plane limits the accurate detection of X chromosomes by immunohistochemistry and FISH in some cells. To overcome this limitation, X chromosome analysis could be performed by different techniques on intact cells isolated from fresh tissue. Additionally, there is no evidence that X chromosome inactivation reoccurs after activation of the Xi during germ cell migration during embryogenesis, limiting the prediction of X chromosome content in germ cells by H3K27me3. Our findings will lay the groundwork for new clinically important studies on exactly when and by which mechanism an extra X chromosome is lost in spermatogonia and Sertoli cells. This study was funded by The Scientific and Technological Research Council of Türkiye (TUBITAK) (2219 - International Postdoctoral Research Fellowship Program for Turkish Citizens) and the Strategic Research Program (SRP89) from the Vrije Universiteit Brussel. The authors declare no competing interests. N/A.

Short-Term Wind Speed Prediction via Sample Entropy: A Hybridisation Approach against Gradient Disappearance and Explosion

High-variant wind speeds cause aberrations in wind power systems and compromise the effective operation of wind farms. A single model cannot capture the inherent wind speed randomness and complexity. In the proposed hybrid strategy, wavelet transform (WT) is used for data decomposition, sample entropy (SampEn) for subseries complexity evaluation, neural network autoregression (NNAR) for deterministic subseries prediction, long short-term memory network (LSTM) for complex subseries prediction, and gradient boosting machine (GBM) for prediction reconciliation. The proposed WT-NNAR-LSTM-GBM approach predicts minutely averaged wind speed data collected at Southern African Universities Radiometric Network (SAURAN) stations: Council for Scientific and Industrial Research (CSIR), Richtersveld (RVD), Venda, and the Namibian University of Science and Technology (NUST). For comparison purposes, in WT-NNAR-LSTM-GBM, LSTM and NNAR are respectively replaced with a k-nearest neighbour (KNN) to form the corresponding hybrids: WT-NNAR-KNN-GBM and WT-KNN-LSTM-GBM. We assessed WT-NNAR-LSTM-GBM’s efficacy against NNAR, LSTM, WT-NNAR-KNN-GBM, and WT-KNN-LSTM-GBM as well as the naïve model. The comparative study found that the WT-NNAR-LSTM-GBM model was the most accurate, sharpest, and robust based on mean absolute error, median absolute deviation, and residual analysis. The study results suggest using short-term forecasts to optimise wind power production, enhance grid operations in real-time, and open the door to further algorithmic enhancements.

A Unified Branch-Price-and-Cut Algorithm for Multicompartment Pickup and Delivery Problems

In this paper, we study the pickup and delivery problem with time windows and multiple compartments (PDPTWMC). The PDPTWMC generalizes the pickup and delivery problem with time windows to vehicles with multiple compartments. In particular, we consider three compartment-related attributes: (1) compartment capacity flexibility that allows the capacities of the compartments to be fixed or flexible, (2) item-to-compartment flexibility that specifies which items are compatible with which compartments, and (3) item-to-item compatibility that considers that incompatible items cannot be simultaneously in the same compartment. To solve the PDPTWMC, we propose an exact branch-price-and-cut algorithm in which the pricing problem is solved by means of a unified bidirectional labeling algorithm. The labeling algorithm can tackle all possible combinations of the studied compartment-related attributes of the PDPTWMC. Furthermore, we implement several acceleration techniques that allow to, among others, reduce the symmetry in the label extensions with empty compartments, the symmetry in the dominance between compartments with similar attributes, and the complexity of the algorithm with fixed compartment capacity. Finally, we introduce benchmark instances for the PDPTWMC and conduct an extensive computational campaign to test the limits of our algorithm and to derive relevant managerial insights in order to highlight the applicability of considering the studied compartment-related attributes. Funding: This work was supported by Nederlandse Organisatie voor Wetenschappelijk Onderzoek [Grant 439.18.459] and the Natural Sciences and Engineering Research Council of Canada [Grant 2017-06106]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/trsc.2023.0252 .

Incentivizing Healthy Food Choices Using Add-On Bundling: A Field Experiment

Problem definition: How can retailers incentivize customers to make healthier food choices? Price, convenience, and taste are known to be among the main drivers behind such choices. Unfortunately, healthier food options are often expensive and not adequately promoted. However, we are observing recent efforts to nudge customers toward healthier food. Methodology/results: In this paper, we conducted a field experiment with a global convenience store chain to better understand how different add-on bundle promotions influence healthy food choices. We considered three types of add-on bundles sequentially: (i) an unhealthy bundle (when customers purchased a coffee, they could add a pastry for $1), (ii) a healthy bundle (offering a healthy snack, such as fruit, vegetable, or protein, as a coffee add-on for $1), and (iii) a choice bundle (the option of either a pastry or a healthy snack as an add-on to coffee for $1). In addition to our field experiment, we conducted an online laboratory study to strengthen the validity of our results. Managerial implications: We found that offering healthy snacks as part of an add-on bundle significantly increased healthy purchases (and decreased unhealthy purchases). Surprisingly, this finding continued to hold for the choice bundle, that is, even when unhealthy snacks were concurrently on promotion. However, we did not observe a long-term stickiness effect, meaning that customers returned to their original (unhealthy) purchase patterns once the healthy or choice bundle was discontinued. Finally, we show that offering an add-on choice bundle is also beneficial for retailers, who can earn higher revenue and profit. Funding: This research was supported by the James McGill Scholar Award Fund, the Scale AI Chair Program, IIVADO (Institut de valorisation des données) Fundamental Research Project Grant, and two Discovery Grants from the Natural Sciences and Engineering Research Council of Canada. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2023.0336 .