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First Sagittarius A* Event Horizon Telescope results. VIII. Physical interpretation of the polarized ring
(American Astronomical Society, 2024-04-01) Akiyama, Kazunori; Alberdi, Antxon; Alef, Walter; Algaba, Juan Carlos; Anantua, Richard; Asada, Keiichi; Azulay, Rebecca; Bach, Uwe; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Bandyopadhyay, Bidisha; Barrett, John; Bauböck, Michi; Benson, Bradford A.; Bintley, Dan; Blackburn, Lindy; Blundell, Raymond; Bouman, Katherine L.; Bower, Geoffrey C.; Boyce, Hope; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broderick, Avery E.; Broguiere, Dominique; Bronzwaer, Thomas; Bustamante, Sandra; Byun, Do-Young; Carlstrom, John E.; Ceccobello, Chiara; Chael, Andrew; Chan, Chi-kwan; Chang, Dominic O.; Chatterjee, Koushik; Chatterjee, Shami; Chen, Ming-Tang; Chen, Yongjun; Cheng, Xiaopeng; Cho, Ilje; Christian, Pierre; Conroy, Nicholas S.; Conway, John E.; Cordes, James M.; Crawford, Thomas M.; Crew, Geoffrey B.; Cruz-Osorio, Alejandro; Cui, Yuzhu; Dahale, Rohan; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Dhruv, Vedant; Dihingia, Indu K.; Doeleman, Sheperd S.; Dougall, Sean; Dzib, Sergio A.; Eatough, Ralph P.; Emami, Razieh; Falcke, Heino; Farah, Joseph; Fish, Vincent L.; Fomalont, Edward; Ford, H. Alyson; Foschi, Marianna; Fraga-Encinas, Raquel; Freeman, William T.; Friberg, Per; Fromm, Christian M.; Fuentes, Antonio; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gómez, José L.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Haggard, Daryl; Haworth, Kari; Hecht, Michael H.; Hesper, Ronald; Heumann, Dirk; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Impellizzeri, C.M. Violette; Inoue, Makoto; Issaoun, Sara; James, David J.; Jannuzi, Buell T.; Janssen, Michael; Jeter, Britton; Jiang, Wu; Jiménez-Rosales, Alejandra; Johnson, Michael D.; Jorstad, Svetlana; Joshi, Abhishek V.; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Dong-Jin; Kim, Jae-Young; Kim, Jongsoo; Kim, Junhan; Kino, Motoki; Koay, Jun Yi; Kocherlakota, Prashant; Kofuji, Yutaro; Koch, Patrick M.; Koyama, Shoko; Kramer, Carsten; Kramer, Joana A.; Kramer, Michael; Krichbaum, Thomas P.; Kuo, Cheng-Yu; La Bella, Noemi; Lauer, Tod R.; Lee, Daeyoung; Lee, Sang-Sung; Leung, Po Kin; Levis, Aviad; Li, Zhiyuan; Lico, Rocco; Lindahl, Greg; Lindqvist, Michael; Lisakov, Mikhail; Liu, Jun; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin J.; Lowitz, Amy E.; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Marchili, Nicola; Markoff, Sera; Marrone, Daniel P.; Marscher, Alan P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Michalik, Daniel; Mizuno, Izumi; Mizuno, Yosuke; Mora, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Mulaudzi, Wanga; Müller, Cornelia; Müller, Hendrik; Mus, Alejandro; Musoke, Gibwa; Myserlis, Ioannis; Nadolski, Andrew; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayanan, Gopal; Natarajan, Iniyan; Nathanail, Antonios; Navarro Fuentes, Santiago; Neilsen, Joey; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Nowak, Michael A.; Oh, Junghwan; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Özel, Feryal; Palumbo, Daniel C.M.; Paraschos, Georgios Filippos; Park, Jongho; Parsons, Harriet; Patel, Nimesh; Pen, Ue-Li; Pesce, Dominic W.; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Pötzl, Felix M.; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ricarte, Angelo; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Romero-Cañizales, Cristina; Ros, Eduardo; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruiz, Ignacio; Ruszczyk, Chet; Rygl, Kazi L.J.; Sánchez, Salvador; Sánchez-Argüelles, David; Sánchez-Portal, Miguel; Sasada, Mahito; Satapathy, Kaushik; Savolainen, Tuomas; Schloerb, F. Peter; Schonfeld, Jonathan; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Sosapanta Salas, León David; Souccar, Kamal; Stanway, Joshua S.; Sun, He; Tazaki, Fumie; Tetarenko, Alexandra J.; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Torne, Pablo; Toscano, Teresa; Traianou, Efthalia; Trent, Tyler; Trippe, Sascha; Turk, Matthew; Van Bemmel, Ilse; Van Langevelde, Huib Jan; Van Rossum, Daniel R.; Vos, Jesse; Wagner, Jan; Ward-Thompson, Derek; Wardle, John; Washington, Jasmin E.; Weintroub, Jonathan; Wharton, Robert; Wielgus, Maciek; Wiik, Kaj; Witzel, Gunther; Wondrak, Michael F.; Wong, George N.; Wu, Qingwen; Yadlapalli, Nitika; Yamaguchi, Paul; Yfantis, Aristomenis; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yu, Wei; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhang, Shuo; Zhao, Guang-Yao; Zhao, Shan-Shan; Najafi-Ziyazi, Mahdi
In a companion paper, we present the first spatially resolved polarized image of Sagittarius A* on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%–28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87*, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of SgrA* (equivalent to ≈46°±12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow.
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Predictors of unsuppressed HIV viral load and low CD4 count among ZIMPHIA 2020 survey participants
(Texila International Journal, 2024-12-27) Mukwenha, Solomon; Dzinamarira, Tafadzwa; Mapingure, Munyaradzi; Chingombe, Innocent; Makota, Rutendo Birri; Mbunge, Elliot; Moyo, Enos; Chemhaka, Garikayi; Batani, John; Moyo, Brian; Musuka, Godfrey
Unsuppressed Viral load and low CD4 counts pose a significant challenge to HIV/AIDS management. Understanding the predictors of unsuppressed viral load and CD4 is critical for developing strategies to mitigate its impact. This study aimed to identify predictors of unsuppressed HIV viral load and low CD4 counts among Zimbabwe population-based HIV impact assessment survey (ZIMPHIA 2020) study participants. We analysed data from the ZIMPHIA 2020 survey. Data collection was done using structured interviews, home-based HIV testing and laboratory testing. Blood samples from participants were tested for HIV and those positive were analysed for CD4 counts and Viral load tests. We then calculated odds ratios for predictors of unsuppressed viral load (viral load ≥1000 copies/mL) and low CD4 counts (CD4< 350). The prevalence of unsuppressed viral load and low CD4 count were 20.7% and 34.7%, respectively. Males were more likely to be virally unsuppressed (25.1%) than females (18.8%) adjusted odds ratio (aOR) (95% confidence interval) 1.74 (1.43-2.11) p-value < 0.001. The odds of having a low CD4 count were higher among males (41%) than females (19%) aOR (95% confidence interval) 3.07 (2.57-3.66). Urban dwellers were more likely to have a low CD4 count (31.1%0 than rural dwellers (23.8%) aOR (95% confidence interval) 1.45 (1.21-1.73) p-value <0.001. The common predictors of both unsuppressed viral load and low CD4 were gender, never tested for HIV and never had a viral load test.
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Factors driving virtual running event participation : A CHAID segmentation approach
(Sage, 2024-12) Frost, Bianca Lizelle; Du Preez, Elizabeth; Jordaan, Yolanda; bianca.frost@up.ac.za
Virtual running events (VREs) have emerged as participatory events and are projected to be a legitimate future segment in the sport event industry. This paper considers the most suitable market segment(s) with future intentions to partake in VREs. A Chi-Squared Automatic Interaction Detector (CHAID) algorithm, scarcely used to segment sport consumer markets, was applied based on various motivational factors that may drive VRE participation. Data were collected from 1,017 individuals who had participated in a VRE. Ten distinct market segments with varying intentions to partake in VREs were identified, uncovering at least six viable future VRE segments. Hedonia, perceived psycho-social risk, perceived price and VRE benefits were the strongest predictors of VRE participation intentions. The CHAID analysis allowed a detailed description of the relative importance of the characteristics within each segment, confirming the benefit of using this sophisticated technique to develop targeted marketing strategies.
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Evaluating factors influencing youth participation in agricultural enterprises : implications for food security and agribusiness
(AOSIS, 2024-11-08) Giwu, Ongama; Mdoda, Lelethu; Ntlanga, Samuel S.; Loki, Olwethu
BACKGROUND : Agriculture is crucial for economic growth, yet youth engagement in agricultural enterprises is declining due to concerns related to perceived profitability, resource access, and social stigmas. Understanding these determinants is vital for fostering youth interest in agriculture and promoting sustainable rural development and food security. AIM : This study examines the factors affecting youth engagement in agricultural enterprises in Umzimvubu Local Municipality, South Africa, and their implications for food security and agribusiness. SETTING : Addressing youth unemployment and enhancing agriculture’s contribution to gross domestic product (GDP) require understanding barriers to youth participation. This study was conducted in Umzimvubu Local Municipality, South Africa. METHODS : A structured questionnaire was administered to 210 youths through stratified random sampling. Descriptive statistics and a univariate probit regression model were used for analysis. RESULTS : Findings indicate male dominance in agriculture, with educational background positively correlating with participation. Single youths showed greater interest than married counterparts. Challenges like land availability and a lack of financial support hinder engagement. Significant determinants include age, education, farming skills, social group membership, and household revenue, while factors like household size, gender, and limited access to credit negatively impact willingness to participate. CONCLUSION : Addressing financial barriers through improved access to loans is essential to enhance youth involvement. Policies should cater to youth-specific traits and environmental challenges to build a resilient agricultural sector driven by young innovators. CONTRIBUTION : The study emphasises the need for a comprehensive policy framework collaboratively developed by the government, the Department of Agriculture, and non-governmental organisations.
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Effect of infrared heat-moisture treatment and cooling rate on the material properties of amylose-lipid complex nanomaterials
(Wiley, 2025-08) Maphumulo, Njabulo Gideon; Masanabo, Mondli Abednicko; Ray, Suprakas Sinha; Emmambux, Mohammad Naushad; naushad.emmambux@up.ac.za
Please read abstract in the article.