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Does wind affect the orientation of vegetation stripes? A copula-based mixture model for axial and circular data
(Wiley, 2025-07) Mingione, Marco; Lagona, Francesco; Nagar, Priyanka; Von Holtzhausen, Francois Victor; Bekker, Andriette, 1958-; Schoombie, Janine; Le Roux, Peter Christiaan
Motivated by a case study of vegetation patterns, we introduce a mixture model with concomitant variables to examine the association between the orientation of vegetation stripes and wind direction. The proposal relies on a novel copula-based bivariate distribution for mixed axial and circular observations and provides a parsimonious and computationally tractable approach to examine the dependence of two environmental variables observed in a complex manifold. The findings suggest that dominant winds shape the orientation of vegetation stripes through a mechanism of neighboring plants providing wind shelter to downwind individuals.
Fertility care in low- and middle income countries : public sector access to medically assisted reproduction in South Africa : a case study
(Bioscientifica Ltd., 2025-07) Boshoff, Gerhardus Marthinus; Ombelet, Willem; Huyser, Carin; gerhard.boshoff@up.ac.za
In South Africa, approximately 10% of the calculated need for medically assisted reproduction is being met due to limited access and unequal availability of these services. To facilitate understanding of challenges associated with access to assisted reproduction, a retrospective case study spanning 6 years was performed at one public sector hospital in South Africa offering these services. Demographic profiles, including income, region of residency and access to medical insurance, of patients seeking assistance to become pregnant were investigated. Patients were categorised as those who underwent diagnostic investigations only vs those who returned for therapeutic procedures, and the difference in demographic profiles between the two groups was determined. This investigation showed that patients from the lower-income classification group, without medical insurance, tend to return for therapeutic procedures less often than those with a higher income and medical insurance, even though these low-income patients qualify for a therapeutic procedure subsidy. An inverse relationship existed where patient numbers decreased as their travel distance increased, but patients who were required to travel further for assisted reproductive therapy tended to return for these procedures more often than patients who resided closer to the medical facility. In conclusion, access to medically assisted reproduction facilities is critically undersupplied and limited in the region. In order to ease the travel distance of patients, alternative primary diagnostic routes with accessible clinics are needed. In addition, costs of therapeutic procedures in the public sector should be re-evaluated to be offered at affordable rates for marginalised patients.
Development of populational female thorax sizes and body habitus categories using computed tomography (CT) images
(Elsevier, 2025-08) Pape, R.; Xie, G.; Zheng, X.; Carstens, Ann; West, C.; Cowling, C.
INTRODUCTION: Positioning of the breast during mammography examination is critical to producing optimum quality images. However, the variation in female thorax and body habitus may affect mammography positioning for best image quality. This study aims to establish populational female thoracic (rib cage) sizes and quantify female body habitus categories.
METHODS: A retrospective analysis of 347 female computed tomography (CT) chest axial scans was retrieved from an open access database to establish female rib cage sizes. Dimensions of the rib cage were measured digitally across six cross sections with six anterior rib landmark points and recorded in millimetres (mm). A Bayesian Network (BN) model was developed to establish the relationships of information extracted from the rib cage image data to quantify and categorise female body habitus.
RESULTS: Female body habitus (thoracic size) were classified into three cohort categories: lean (20.5 %),norm (55.6 %) and curvaceous (23.9 %). The mean values (115–126 mm) and the corresponding 80 %prediction interval ranges for the healthy female rib cage size were obtained through the BN scenario analysis.
CONCLUSION: The significance of this study is that it categorised 55.6 % of female thoracic sizes as being normal on a larger group of female population. This study contributed to a good understanding of the range of female body habitus (thoracic size) to improve positioning practice and maximize image quality.
IMPLICATIONS FOR PRACTICE: This study used a BN model to establish a range of female thorax sizes using CT chest images to support improved positioning practices. These ranges of thorax sizes should be integrated as a body habitus criterion in the current image evaluation system to maximise image quality and subsequent breast cancer diagnosis.
Polyploid-diploid coexistence in the greater duckweed Spirodela polyrhiza
(Wiley, 2025) Mortier, Frederik; Van de Peer, Yves; Bonte, Dries
Polyploidy is widespread among plants and is often associated with stressful environments that can facilitate their establishment. Successful new polyploids must overcome competitive disadvantages against their progenitors or benefit from negative frequency-dependent growth.
We tested the invasion of neotetraploid duckweed strains (Spirodela polyrhiza) into populations of their diploid progenitors in control and salt stress conditions in replicated microcosms. We also tested the reverse scenario: invasion of diploids in neotetraploid populations, to examine the impact of the initial tetraploid proportion.
Tetraploid proportions declined in all tetraploid and diploid invasions, with different rates than predicted from only intrinsic growth rate differences. Salt stress affected the decline in a strain-specific manner. We found evidence for negative frequency-dependent growth that, nonetheless, was insufficient to overcome competitive disadvantages of neopolyploids.
SYNTHESIS. Our findings demonstrate the crucial role of competition and frequency dependence on neopolyploid establishment. Therefore, we caution against inferring neopolyploid success based solely on intrinsic growth rates.
Developing online considerations for the IASWG standards on social work with groups : a tribute to Charles Garvin
(Routledge, 2025) Macgowan, Mark J.; Gardella, Lorrie Greenhouse; Simon, Shirley R.; Prinsloo, Reineth; Baar, Hilda; Seck, Mamadou; Astray, Andres Arias; Canizares, Catalina; Muskat, Barbara
In the spring of 2020, when the COVID-19 pandemic necessitated the remote delivery of health and human services, few social workers were prepared to facilitate online groups. Research on virtual group work was limited, and the IASWG Standards for Social Work Practice with Groups offered minimal guidance for online practice. Charles Garvin encouraged the International Association for Social Work with Groups (IASWG) to enhance the Standards with “online considerations” that would support effective group work in virtual environments. Serving as a mentor and active member of the Task Force on Online Considerations, Charles Garvin inspired a systematic, collaborative, and internationally inclusive process that exemplified principles of socially just research. This paper describes the research and development of the online considerations and the limitations and possibilities of defining international guidelines for social work with groups.