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195 results on '"Schoeman J"'

1. Augmenting the action space with conventions to improve multi-agent cooperation in Hanabi

Author

Bredell, F., Engelbrecht, H. A., and Schoeman, J. C.

Subjects
Computer Science - Multiagent Systems, Computer Science - Artificial Intelligence, Computer Science - Machine Learning
Abstract

The card game Hanabi is considered a strong medium for the testing and development of multi-agent reinforcement learning (MARL) algorithms, due to its cooperative nature, hidden information, limited communication and remarkable complexity. Previous research efforts have explored the capabilities of MARL algorithms within Hanabi, focusing largely on advanced architecture design and algorithmic manipulations to achieve state-of-the-art performance for a various number of cooperators. However, this often leads to complex solution strategies with high computational cost and requiring large amounts of training data. For humans to solve the Hanabi game effectively, they require the use of conventions, which often allows for a means to implicitly convey ideas or knowledge based on a predefined, and mutually agreed upon, set of ``rules''. Multi-agent problems containing partial observability, especially when limited communication is present, can benefit greatly from the use of implicit knowledge sharing. In this paper, we propose a novel approach to augmenting the action space using conventions, which act as special cooperative actions that span over multiple time steps and multiple agents, requiring agents to actively opt in for it to reach fruition. These conventions are based on existing human conventions, and result in a significant improvement on the performance of existing techniques for self-play and cross-play across a various number of cooperators within Hanabi., Comment: This paper is under review at the journal of autonomous agents and multi-agent systems (JAAMAS)

Published
2024

2. Lossy compression of observations for Gaussian process regression

Author

Visser Emile, van Daalen Corné E., and Schoeman J. C.

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

This paper proposes a novel approach of Gaussian process observation set compression based on a squared difference measure. It is used to discard observations to speed up Gaussian process prediction while retaining the information encoded in the full set of observations. Furthermore, this paper compares the regression performance of a compressed Gaussian process to its uncompressed version and to a randomly downsampled Gaussian process for a standard two-dimensional test function. The empirical results of this paper show that this is an effective algorithm for Gaussian process compression, speeding up prediction while maintaining predictive accuracy with regards to the predicted means.

Published
2022
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3. LABCAT: Locally adaptive Bayesian optimization using principal-component-aligned trust regions

Author

Visser, E., van Daalen, C. E., and Schoeman, J. C.

Subjects
Computer Science - Machine Learning
Abstract

Bayesian optimization (BO) is a popular method for optimizing expensive black-box functions. BO has several well-documented shortcomings, including computational slowdown with longer optimization runs, poor suitability for non-stationary or ill-conditioned objective functions, and poor convergence characteristics. Several algorithms have been proposed that incorporate local strategies, such as trust regions, into BO to mitigate these limitations; however, none address all of them satisfactorily. To address these shortcomings, we propose the LABCAT algorithm, which extends trust-region-based BO by adding a rotation aligning the trust region with the weighted principal components and an adaptive rescaling strategy based on the length-scales of a local Gaussian process surrogate model with automatic relevance determination. Through extensive numerical experiments using a set of synthetic test functions and the well-known COCO benchmarking software, we show that the LABCAT algorithm outperforms several state-of-the-art BO and other black-box optimization algorithms.

Published
2023

4. Credit-cognisant reinforcement learning for multi-agent cooperation

Author

Bredell, F., Engelbrecht, H. A., and Schoeman, J. C.

Subjects
Computer Science - Machine Learning, Computer Science - Multiagent Systems
Abstract

Traditional multi-agent reinforcement learning (MARL) algorithms, such as independent Q-learning, struggle when presented with partially observable scenarios, and where agents are required to develop delicate action sequences. This is often the result of the reward for a good action only being available after other agents have taken theirs, and these actions are not credited accordingly. Recurrent neural networks have proven to be a viable solution strategy for solving these types of problems, resulting in significant performance increase when compared to other methods. In this paper, we explore a different approach and focus on the experiences used to update the action-value functions of each agent. We introduce the concept of credit-cognisant rewards (CCRs), which allows an agent to perceive the effect its actions had on the environment as well as on its co-agents. We show that by manipulating these experiences and constructing the reward contained within them to include the rewards received by all the agents within the same action sequence, we are able to improve significantly on the performance of independent deep Q-learning as well as deep recurrent Q-learning. We evaluate and test the performance of CCRs when applied to deep reinforcement learning techniques at the hands of a simplified version of the popular card game Hanabi., Comment: 11 pages, 6 figures, 1 appendix, submitted to IEEE Transaction on Games

Published
2022

5. Degenerate Gaussian factors for probabilistic inference

Author

Schoeman, J. C., van Daalen, C. E., and Preez, J. A. du

Subjects
Computer Science - Machine Learning, Statistics - Machine Learning
Abstract

In this paper, we propose a parametrised factor that enables inference on Gaussian networks where linear dependencies exist among the random variables. Our factor representation is effectively a generalisation of traditional Gaussian parametrisations where the positive-definite constraint of the covariance matrix has been relaxed. For this purpose, we derive various statistical operations and results (such as marginalisation, multiplication and affine transformations of random variables) that extend the capabilities of Gaussian factors to these degenerate settings. By using this principled factor definition, degeneracies can be accommodated accurately and automatically at little additional computational cost. As illustration, we apply our methodology to a representative example involving recursive state estimation of cooperative mobile robots., Comment: Accepted by International Journal of Approximate Reasoning on 17 January 2022

Published
2021
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7. Agreement between measured energy expenditure and predictive energy equations in paediatric oncology.

Author

Kellerman, I, Kruger, M, Schoeman, J, and Blaauw, R

Abstract

Optimal nutritional support in childhood cancer relies on the adequate provision of energy. This study investigated the impact of chemotherapy on resting energy expenditure (REE) during the first six months of treatment and the accuracy of predictive equations in calculating said requirements of newly diagnosed children with cancer. REE was measured at diagnosis utilising a validated bioelectrical impedance analysis (BIA) mobile unit and compared with three predictive equations (Schofield 1985, World Health Organization [WHO] 1985 and the Recommended Dietary Allowance [RDA] 1989). Agreement and accuracy of these equations were tested by determining bias and agreement rates and displayed using the Bland–Altman plot. Baseline values were plotted against monthly follow-up measurements over time. Statistical significance was 5% and a priori limits of agreement set between 90% and 110% of measured REE. Forty-three newly diagnosed children with median age 4 years (IQR 2.0–7.6) were measured prior to chemotherapy initiation. Compared with measured REE (mean ± SD) 719.53 ± 206.29 kcal/day, all predictive equations significantly overestimated REE: WHO 1985 (889.75 ± 323.31 kcal/day; 23% overestimation), Schofield 1985 (899.62 ± 336.10 kcal/day; 25% overestimation) and RDA (1647.67 ± 481.06 kcal/day; 129% overestimation) (p < 0.001). Despite significant proportionate bias in all three equations (p < 0.001), the intra-class consistency coefficient showed good reliability for the Schofield 1985 (0.864) and WHO 1985 (0.849) equations. Though statistically significant (chi-square = 23.11, p < 0.003), the overall 1 kcal/kg (1.3%) increase for all cancer types at six months may not be clinically significant. Existing predictive equations are unable to calculate REE accurately at childhood cancer diagnosis, highlighting the need for future investigations into the development of cancer-specific equations. [ABSTRACT FROM AUTHOR]

Published
2024
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11. Host directed therapies for tuberculous meningitis [version 2; peer review: 1 approved, 1 approved with reservations]

Author

Davis, A, Donovan, J, Bremer, M, Van Toorn, R, Schoeman, J, Dadabhoy, A, Lai, RPJ, Cresswell, F, Boulware, D, Wilkinson, R, Thuong, NTT, Thwaites, G, Bahr, N, and Tuberculous Meningitis International Research Consortium

Subjects
Tuberculous Meningitis International Research Consortium, urologic and male genital diseases
Abstract

A dysregulated host immune response significantly contributes to morbidity and mortality in tuberculous meningitis (TBM). Effective host directed therapies (HDTs) are critical to improve survival and clinical outcomes. Currently only one HDT, dexamethasone, is proven to improve mortality. However, there is no evidence dexamethasone reduces morbidity, how it reduces mortality is uncertain, and it has no proven benefit in HIV co-infected individuals. Further research on these aspects of its use, as well as alternative HDTs such as aspirin, thalidomide and other immunomodulatory drugs is needed. Based on new knowledge from pathogenesis studies, repurposed therapeutics which act upon small molecule drug targets may also have a role in TBM. Here we review existing literature investigating HDTs in TBM, and propose new rationale for the use of novel and repurposed drugs. We also discuss host variable responses and evidence to support a personalised approach to HDTs in TBM.

Published
2020

12. Host directed therapies for tuberculous meningitis [version 1; peer review: 1 approved with reservations]

Author

Davis, AG, Donovan, J, Bremer, M, Van Toorn, R, Schoeman, J, Dadabhoy, A, Lai, RPJ, Cresswell, FV, Boulware, DR, Wilkinson, RJ, Thuong, NTT, Thwaites, GE, and Bahr, NC

Subjects
Tuberculous Meningitis International Research Consortium, urologic and male genital diseases
Abstract

A dysregulated host immune response significantly contributes to morbidity and mortality in tuberculous meningitis (TBM). Effective host directed therapies (HDTs) are critical to improve survival and clinical outcomes. Currently only one HDT, dexamethasone, is proven to improve mortality. However, there is no evidence dexamethasone reduces morbidity, how it reduces mortality is uncertain, and it has no proven benefit in HIV co-infected individuals. Further research on these aspects of its use, as well as alternative HDTs such as aspirin, thalidomide and other immunomodulatory drugs is needed. Based on new knowledge from pathogenesis studies, repurposed therapeutics which act upon small molecule drug targets may also have a role in TBM. Here we review existing literature investigating HDTs in TBM, and propose new rationale for the use of novel and repurposed drugs. We also discuss host variable responses and evidence to support a personalised approach to HDTs in TBM.

Published
2020

13. Metabolic response of blood vessels to TNF alpha

Author

Junaid, A., Schoeman, J., Yang, W., Stam, W., Mashaghi, A., Zonneveld, A.J. van, and Hankemeier, T.

Abstract

TNF alpha signaling in the vascular endothelium elicits multiple inflammatory responses that drive vascular destabilization and leakage. Bioactive lipids are main drivers of these processes. In vitro mechanistic studies of bioactive lipids have been largely based on two-dimensional endothelial cell cultures that, due to lack of laminar flow and the growth of the cells on noncompliant stiff substrates, often display a pro-inflammatory phenotype. This complicates the assessment of inflammatory processes. Three-dimensional microvessels-on-a-chip models provide a unique opportunity to generate endothelial microvessels in a more physiological environment. Using an optimized targeted liquid chromatography-tandem mass spectrometry measurements of a panel of pro- and anti-inflammatory bioactive lipids, we measure the profile changes upon administration of TNF alpha. We demonstrate that bioactive lipid profiles can be readily detected from three-dimensional microvessels-on-a-chip and display a more dynamic, less inflammatory response to TNF alpha, that resembles more the human situation, compared to classical two-dimensional endothelial cell cultures.

Published
2020

14. Long-term follow-up of owned, free-roaming dogs in South Africa naturally exposed to Babesia rossi

Author

Morters, M K, Archer, J, Ma, D, Matthee, O, Goddard, A, Leisewitz, A L, Matjila, P T, Wood, J L N, Schoeman, J P, Morters, M K, Archer, J, Ma, D, Matthee, O, Goddard, A, Leisewitz, A L, Matjila, P T, Wood, J L N, and Schoeman, J P

Abstract

Babesia rossi is an important, tick-borne intraerythrocytic protozoan parasite; however, its natural history and epidemiology is poorly understood. Babesia rossi is the most virulent Babesia sp. in domestic dogs and is generally considered to cause severe babesiosis, which is fatal if left untreated. However, subclinical infections and mild disease from B. rossi have been reported, although the clinical progression of these cases was not reported. Therefore, to better understand B. rossi under field conditions, we evaluated its clinical progression and seroprevalence in an owned, free-roaming dog population in Zenzele, South Africa, where the parasite is endemic and prevention is not routine. The entire dog population in Zenzele was monitored intensively at the individual level from March 2008 until April 2014, primarily for a longitudinal study on rabies control. Subsequent evaluation of B. rossi comprised analyses of clinical and laboratory data collected from the Zenzele dog population during the 6 year study period. A substantial proportion (31% (n = 34)) of 109 dogs (randomly selected from every available dog in February/March 2010 older than ~6-8 weeks (n = 246)) tested by Indirect Fluorescent Antibody Test had seroconverted strongly to B. rossi. All 34 dogs were generally consistently healthy adults, determined from regular clinical examinations between March 2008 and April 2014. Blood smear examinations at multiple time points between July 2009 and February 2011 were also undertaken for almost all of these (34) seropositive dogs and all those tested were consistently negative for Babesia spp. Subclinical infections and mild disease were also the main findings for a separate group of 18 dogs positive for Babesia spp. on blood smear examination and confirmed to be infected with B. rossi by Polymerase Chain Reaction - Reverse Line Blot. Almost all of these dogs were positive at only one time point from repeat blood smear examinations between July 2009 and Febru

Published
2020

15. Global Retinoblastoma Presentation and Analysis by National Income Level

Author

Fabian, ID, Abdallah, E, Abdullahi, SU, Abdulqader, RA, Boubacar, SA, Ademola-Popoola, DS, Adio, A, Afshar, AR, Aggarwal, P, Aghaji, AE, Ahmad, A, Akib, MNR, Al Harby, L, Al Ani, MH, Alakbarova, A, Portabella, SA, Al-Badri, SAF, Alcasabas, APA, Al-Dahmash, SA, Alejos, A, Alemany-Rubio, E, Bio, AIA, Carreras, YA, Al-Haddad, C, Al-Hussaini, HHY, Ali, AM, Alia, DB, Al-Jadiry, MF, Al-Jumaly, U, Alkatan, HM, All-Eriksson, C, Al-Mafrachi, AARM, Almeida, AA, Alsawidi, KM, Al-Shaheen, AASM, Al-Shammary, EH, Amiruddin, PO, Antonino, R, Astbury, NJ, Atalay, HT, Atchaneeyasakul, L-O, Atsiaya, R, Attaseth, T, Aung, TH, Ayala, S, Baizakova, B, Balaguer, J, Balayeva, R, Balwierz, W, Barranco, H, Bascaran, C, Popovic, MB, Benavides, R, Benmiloud, S, Guebessi, NB, Berete, RC, Berry, JL, Bhaduri, A, Bhat, S, Biddulph, SJ, Biewald, EM, Bobrova, N, Boehme, M, Boldt, HC, Bonanomi, MTBC, Bornfeld, N, Bouda, GC, Bouguila, H, Boumedane, A, Brennan, RC, Brichard, BG, Buaboonnam, J, Calderon-Sotelo, P, Calle Jara, DA, Camuglia, JE, Cano, MR, Capra, M, Cassoux, N, Castela, G, Castillo, L, Catala-Mora, J, Chantada, GL, Chaudhry, S, Chaugule, SS, Chauhan, A, Chawla, B, Chernodrinska, VS, Chiwanga, FS, Chuluunbat, T, Cieslik, K, Cockcroft, RL, Comsa, C, Correa, ZM, Correa Llano, MG, Corson, TW, Cowan-Lyn, KE, Csoka, M, Cui, X, Da Gama, I, Dangboon, W, Das, A, Das, S, Davanzo, JM, Davidson, A, De Potter, P, Delgado, KQ, Demirci, H, Desjardins, L, Diaz Coronado, RY, Dimaras, H, Dodgshun, AJ, Donaldson, C, Donato Macedo, CR, Dragomir, MD, Du, Y, Du Bruyn, M, Edison, KS, Sutyawan, IWE, El Kettani, A, Elbahi, AM, Elder, JE, Elgalaly, D, Elhaddad, AM, Elhassan, MMA, Elzembely, MM, Essuman, VA, Evina, TGA, Fadoo, Z, Fandino, AC, Faranoush, M, Fasina, O, Fernandez, DDPG, Fernandez-Teijeiro, A, Foster, A, Frenkel, S, Fu, LD, Fuentes-Alabi, SL, Gallie, BL, Gandiwa, M, Garcia, JL, Garcia Aldana, D, Gassant, PY, Geel, JA, Ghassemi, F, Giron, A, Gizachew, Z, Goenz, MA, Gold, AS, Goldberg-Lavid, M, Gole, GA, Gomel, N, Gonzalez, E, Gonzalez Perez, G, Gonzalez-Rodriguez, L, Garcia Pacheco, HN, Graells, J, Green, L, Gregersen, PA, Grigorovski, NDAK, Guedenon, KM, Gunasekera, DS, Gunduz, AK, Gupta, H, Gupta, S, Hadjistilianou, T, Hamel, P, Hamid, SA, Hamzah, N, Hansen, ED, Harbour, JW, Hartnett, ME, Hasanreisoglu, M, Hassan, S, Hederova, S, Hernandez, J, Carcamo Hernandez, LM, Hessissen, L, Hordofa, DF, Huang, LC, Hubbard, GB, Hummlen, M, Husakova, K, Al-Janabi, ANH, Ida, R, Ilic, VR, Jairaj, V, Jeeva, I, Jenkinson, H, Ji, X, Jo, DH, Johnson, KP, Johnson, WJ, Jones, MM, Kabesha, TBA, Kabore, RL, Kaliki, S, Kalinaki, A, Kantar, M, Kao, L-Y, Kardava, T, Kebudi, R, Kepak, T, Keren-Froim, N, Khan, ZJ, Khaqan, HA, Khauv, P, Kheir, WJ, Khetan, V, Khodabande, A, Khotenashvili, Z, Kim, JW, Kim, JH, Kiratli, H, Kivela, TT, Klett, A, Palet, JEKK, Krivaitiene, D, Kruger, M, Kulvichit, K, Kuntorini, MW, Kyara, A, Lachmann, ES, Lam, CPS, Lam, GC, Larson, SA, Latinovic, S, Laurenti, KD, Le, BHA, Lecuona, K, Leverant, AA, Li, C, Limbu, B, Quah, BL, Lopez, JP, Lukamba, RM, Lumbroso, L, Luna-Fineman, S, Lutfi, D, Lysytsia, L, Magrath, GN, Mahajan, A, Majeed, AR, Maka, E, Makan, M, Makimbetov, EK, Manda, C, Martin Begue, N, Mason, L, Mason, JO, Matende, IO, Materin, M, Mattosinho, CCDS, Matua, M, Mayet, I, Mbumba, FB, McKenzie, JD, Medina-Sanson, A, Mehrvar, A, Mengesha, AA, Menon, V, Mercado, GJVD, Mets, MB, Midena, E, Mishra, DKC, Mndeme, FG, Mohamedani, AA, Mohammad, MT, Moll, AC, Montero, MM, Morales, RA, Moreira, C, Mruthyunjaya, P, Msina, MS, Msukwa, G, Mudaliar, SS, Muma, K, Munier, FL, Murgoi, G, Murray, TG, Musa, KO, Mushtaq, A, Mustak, H, Muyen, OM, Naidu, G, Nair, AG, Naumenko, L, Roth, PAN, Nency, YM, Neroev, V, Ngo, H, Nieves, RM, Nikitovic, M, Nkanga, ED, Nkumbe, H, Nuruddin, M, Nyaywa, M, Obono-Obiang, G, Oguego, NC, Olechowski, A, Oliver, SCN, Osei-Bonsu, P, Ossandon, D, Paez-Escamilla, MA, Pagarra, H, Painter, SL, Paintsil, V, Paiva, L, Pal, BP, Palanivelu, MS, Papyan, R, Parrozzani, R, Parulekar, M, Morales, CRP, Paton, KE, Pawinska-Wasikowska, K, Pe'er, J, Pena, A, Peric, S, Pham, CTM, Philbert, R, Plager, DA, Pochop, P, Polania, RA, Polyakov, VG, Pompe, MT, Pons, JJ, Prat, D, Prom, V, Purwanto, I, Qadir, AO, Qayyum, S, Qian, J, Rahman, A, Rahman, S, Rahmat, J, Rajkarnikar, P, Ramanjulu, R, Ramasubramanian, A, Ramirez-Ortiz, MA, Raobela, L, Rashid, R, Reddy, MA, Reich, E, Renner, LA, Reynders, D, Ribadu, D, Riheia, MM, Ritter-Sovinz, P, Rojanaporn, D, Romero, L, Roy, SR, Saab, RH, Saakyan, S, Sabhan, AH, Sagoo, MS, Said, AMA, Saiju, R, Salas, B, San Roman Pacheco, S, Sanchez, GL, Sayalith, P, Scanlan, TA, Schefler, AC, Schoeman, J, Sedaghat, A, Seregard, S, Seth, R, Shah, AS, Shakoor, SA, Sharma, MK, Sherief, ST, Shetye, NG, Shields, CL, Siddiqui, SN, Cheikh, SS, Silva, S, Singh, AD, Singh, N, Singh, U, Singha, P, Sitorus, RS, Skalet, AH, Soebagjo, HD, Sorochynska, T, Ssali, G, Stacey, AW, Staffieri, SE, Stahl, ED, Stathopoulos, C, Kranjc, BS, Stones, DK, Strahlendorf, C, Suarez, MEC, Sultana, S, Sun, X, Sundy, M, Superstein, R, Supriyadi, E, Surukrattanaskul, S, Suzuki, S, Svojgr, K, Sylla, F, Tamamyan, G, Tan, D, Tandili, A, Tarrillo Leiva, FF, Tashvighi, M, Tateshi, B, Tehuteru, ES, Teixeira, LF, Teh, KH, Theophile, T, Toledano, H, Trang, DL, Traore, F, Trichaiyaporn, S, Tuncer, S, Tyau-Tyau, H, Umar, AB, Unal, E, Uner, OE, Urbak, SF, Ushakova, TL, Usmanov, RH, Valeina, S, Wijsard, MVH, Varadisai, A, Vasquez, L, Vaughan, LO, Veleva-Krasteva, NV, Verma, N, Victor, AA, Viksnins, M, Villacos Chafla, EG, Vishnevskia-Dai, V, Vora, T, Wachtel, AE, Wackernagel, W, Waddell, K, Wade, PD, Wali, AH, Wang, Y-Z, Weiss, A, Wilson, MW, Wime, ADC, Wiwatwongwana, A, Wiwatwongwana, D, Dod, CW, Wongwai, P, Xiang, D, Xiao, Y, Yam, JC, Yang, H, Yanga, JM, Yaqub, MA, Yarovaya, VA, Yarovoy, AA, Ye, H, Yousef, YA, Yuliawati, P, Zapata Lopez, AM, Zein, E, Zhang, C, Zhang, Y, Zhao, J, Zheng, X, Zhilyaeva, K, Zia, N, Ziko, OAO, Zondervan, M, Bowman, R, Fabian, ID, Abdallah, E, Abdullahi, SU, Abdulqader, RA, Boubacar, SA, Ademola-Popoola, DS, Adio, A, Afshar, AR, Aggarwal, P, Aghaji, AE, Ahmad, A, Akib, MNR, Al Harby, L, Al Ani, MH, Alakbarova, A, Portabella, SA, Al-Badri, SAF, Alcasabas, APA, Al-Dahmash, SA, Alejos, A, Alemany-Rubio, E, Bio, AIA, Carreras, YA, Al-Haddad, C, Al-Hussaini, HHY, Ali, AM, Alia, DB, Al-Jadiry, MF, Al-Jumaly, U, Alkatan, HM, All-Eriksson, C, Al-Mafrachi, AARM, Almeida, AA, Alsawidi, KM, Al-Shaheen, AASM, Al-Shammary, EH, Amiruddin, PO, Antonino, R, Astbury, NJ, Atalay, HT, Atchaneeyasakul, L-O, Atsiaya, R, Attaseth, T, Aung, TH, Ayala, S, Baizakova, B, Balaguer, J, Balayeva, R, Balwierz, W, Barranco, H, Bascaran, C, Popovic, MB, Benavides, R, Benmiloud, S, Guebessi, NB, Berete, RC, Berry, JL, Bhaduri, A, Bhat, S, Biddulph, SJ, Biewald, EM, Bobrova, N, Boehme, M, Boldt, HC, Bonanomi, MTBC, Bornfeld, N, Bouda, GC, Bouguila, H, Boumedane, A, Brennan, RC, Brichard, BG, Buaboonnam, J, Calderon-Sotelo, P, Calle Jara, DA, Camuglia, JE, Cano, MR, Capra, M, Cassoux, N, Castela, G, Castillo, L, Catala-Mora, J, Chantada, GL, Chaudhry, S, Chaugule, SS, Chauhan, A, Chawla, B, Chernodrinska, VS, Chiwanga, FS, Chuluunbat, T, Cieslik, K, Cockcroft, RL, Comsa, C, Correa, ZM, Correa Llano, MG, Corson, TW, Cowan-Lyn, KE, Csoka, M, Cui, X, Da Gama, I, Dangboon, W, Das, A, Das, S, Davanzo, JM, Davidson, A, De Potter, P, Delgado, KQ, Demirci, H, Desjardins, L, Diaz Coronado, RY, Dimaras, H, Dodgshun, AJ, Donaldson, C, Donato Macedo, CR, Dragomir, MD, Du, Y, Du Bruyn, M, Edison, KS, Sutyawan, IWE, El Kettani, A, Elbahi, AM, Elder, JE, Elgalaly, D, Elhaddad, AM, Elhassan, MMA, Elzembely, MM, Essuman, VA, Evina, TGA, Fadoo, Z, Fandino, AC, Faranoush, M, Fasina, O, Fernandez, DDPG, Fernandez-Teijeiro, A, Foster, A, Frenkel, S, Fu, LD, Fuentes-Alabi, SL, Gallie, BL, Gandiwa, M, Garcia, JL, Garcia Aldana, D, Gassant, PY, Geel, JA, Ghassemi, F, Giron, A, Gizachew, Z, Goenz, MA, Gold, AS, Goldberg-Lavid, M, Gole, GA, Gomel, N, Gonzalez, E, Gonzalez Perez, G, Gonzalez-Rodriguez, L, Garcia Pacheco, HN, Graells, J, Green, L, Gregersen, PA, Grigorovski, NDAK, Guedenon, KM, Gunasekera, DS, Gunduz, AK, Gupta, H, Gupta, S, Hadjistilianou, T, Hamel, P, Hamid, SA, Hamzah, N, Hansen, ED, Harbour, JW, Hartnett, ME, Hasanreisoglu, M, Hassan, S, Hederova, S, Hernandez, J, Carcamo Hernandez, LM, Hessissen, L, Hordofa, DF, Huang, LC, Hubbard, GB, Hummlen, M, Husakova, K, Al-Janabi, ANH, Ida, R, Ilic, VR, Jairaj, V, Jeeva, I, Jenkinson, H, Ji, X, Jo, DH, Johnson, KP, Johnson, WJ, Jones, MM, Kabesha, TBA, Kabore, RL, Kaliki, S, Kalinaki, A, Kantar, M, Kao, L-Y, Kardava, T, Kebudi, R, Kepak, T, Keren-Froim, N, Khan, ZJ, Khaqan, HA, Khauv, P, Kheir, WJ, Khetan, V, Khodabande, A, Khotenashvili, Z, Kim, JW, Kim, JH, Kiratli, H, Kivela, TT, Klett, A, Palet, JEKK, Krivaitiene, D, Kruger, M, Kulvichit, K, Kuntorini, MW, Kyara, A, Lachmann, ES, Lam, CPS, Lam, GC, Larson, SA, Latinovic, S, Laurenti, KD, Le, BHA, Lecuona, K, Leverant, AA, Li, C, Limbu, B, Quah, BL, Lopez, JP, Lukamba, RM, Lumbroso, L, Luna-Fineman, S, Lutfi, D, Lysytsia, L, Magrath, GN, Mahajan, A, Majeed, AR, Maka, E, Makan, M, Makimbetov, EK, Manda, C, Martin Begue, N, Mason, L, Mason, JO, Matende, IO, Materin, M, Mattosinho, CCDS, Matua, M, Mayet, I, Mbumba, FB, McKenzie, JD, Medina-Sanson, A, Mehrvar, A, Mengesha, AA, Menon, V, Mercado, GJVD, Mets, MB, Midena, E, Mishra, DKC, Mndeme, FG, Mohamedani, AA, Mohammad, MT, Moll, AC, Montero, MM, Morales, RA, Moreira, C, Mruthyunjaya, P, Msina, MS, Msukwa, G, Mudaliar, SS, Muma, K, Munier, FL, Murgoi, G, Murray, TG, Musa, KO, Mushtaq, A, Mustak, H, Muyen, OM, Naidu, G, Nair, AG, Naumenko, L, Roth, PAN, Nency, YM, Neroev, V, Ngo, H, Nieves, RM, Nikitovic, M, Nkanga, ED, Nkumbe, H, Nuruddin, M, Nyaywa, M, Obono-Obiang, G, Oguego, NC, Olechowski, A, Oliver, SCN, Osei-Bonsu, P, Ossandon, D, Paez-Escamilla, MA, Pagarra, H, Painter, SL, Paintsil, V, Paiva, L, Pal, BP, Palanivelu, MS, Papyan, R, Parrozzani, R, Parulekar, M, Morales, CRP, Paton, KE, Pawinska-Wasikowska, K, Pe'er, J, Pena, A, Peric, S, Pham, CTM, Philbert, R, Plager, DA, Pochop, P, Polania, RA, Polyakov, VG, Pompe, MT, Pons, JJ, Prat, D, Prom, V, Purwanto, I, Qadir, AO, Qayyum, S, Qian, J, Rahman, A, Rahman, S, Rahmat, J, Rajkarnikar, P, Ramanjulu, R, Ramasubramanian, A, Ramirez-Ortiz, MA, Raobela, L, Rashid, R, Reddy, MA, Reich, E, Renner, LA, Reynders, D, Ribadu, D, Riheia, MM, Ritter-Sovinz, P, Rojanaporn, D, Romero, L, Roy, SR, Saab, RH, Saakyan, S, Sabhan, AH, Sagoo, MS, Said, AMA, Saiju, R, Salas, B, San Roman Pacheco, S, Sanchez, GL, Sayalith, P, Scanlan, TA, Schefler, AC, Schoeman, J, Sedaghat, A, Seregard, S, Seth, R, Shah, AS, Shakoor, SA, Sharma, MK, Sherief, ST, Shetye, NG, Shields, CL, Siddiqui, SN, Cheikh, SS, Silva, S, Singh, AD, Singh, N, Singh, U, Singha, P, Sitorus, RS, Skalet, AH, Soebagjo, HD, Sorochynska, T, Ssali, G, Stacey, AW, Staffieri, SE, Stahl, ED, Stathopoulos, C, Kranjc, BS, Stones, DK, Strahlendorf, C, Suarez, MEC, Sultana, S, Sun, X, Sundy, M, Superstein, R, Supriyadi, E, Surukrattanaskul, S, Suzuki, S, Svojgr, K, Sylla, F, Tamamyan, G, Tan, D, Tandili, A, Tarrillo Leiva, FF, Tashvighi, M, Tateshi, B, Tehuteru, ES, Teixeira, LF, Teh, KH, Theophile, T, Toledano, H, Trang, DL, Traore, F, Trichaiyaporn, S, Tuncer, S, Tyau-Tyau, H, Umar, AB, Unal, E, Uner, OE, Urbak, SF, Ushakova, TL, Usmanov, RH, Valeina, S, Wijsard, MVH, Varadisai, A, Vasquez, L, Vaughan, LO, Veleva-Krasteva, NV, Verma, N, Victor, AA, Viksnins, M, Villacos Chafla, EG, Vishnevskia-Dai, V, Vora, T, Wachtel, AE, Wackernagel, W, Waddell, K, Wade, PD, Wali, AH, Wang, Y-Z, Weiss, A, Wilson, MW, Wime, ADC, Wiwatwongwana, A, Wiwatwongwana, D, Dod, CW, Wongwai, P, Xiang, D, Xiao, Y, Yam, JC, Yang, H, Yanga, JM, Yaqub, MA, Yarovaya, VA, Yarovoy, AA, Ye, H, Yousef, YA, Yuliawati, P, Zapata Lopez, AM, Zein, E, Zhang, C, Zhang, Y, Zhao, J, Zheng, X, Zhilyaeva, K, Zia, N, Ziko, OAO, Zondervan, M, and Bowman, R

Abstract

IMPORTANCE: Early diagnosis of retinoblastoma, the most common intraocular cancer, can save both a child's life and vision. However, anecdotal evidence suggests that many children across the world are diagnosed late. To our knowledge, the clinical presentation of retinoblastoma has never been assessed on a global scale. OBJECTIVES: To report the retinoblastoma stage at diagnosis in patients across the world during a single year, to investigate associations between clinical variables and national income level, and to investigate risk factors for advanced disease at diagnosis. DESIGN, SETTING, AND PARTICIPANTS: A total of 278 retinoblastoma treatment centers were recruited from June 2017 through December 2018 to participate in a cross-sectional analysis of treatment-naive patients with retinoblastoma who were diagnosed in 2017. MAIN OUTCOMES AND MEASURES: Age at presentation, proportion of familial history of retinoblastoma, and tumor stage and metastasis. RESULTS: The cohort included 4351 new patients from 153 countries; the median age at diagnosis was 30.5 (interquartile range, 18.3-45.9) months, and 1976 patients (45.4%) were female. Most patients (n = 3685 [84.7%]) were from low- and middle-income countries (LMICs). Globally, the most common indication for referral was leukocoria (n = 2638 [62.8%]), followed by strabismus (n = 429 [10.2%]) and proptosis (n = 309 [7.4%]). Patients from high-income countries (HICs) were diagnosed at a median age of 14.1 months, with 656 of 666 (98.5%) patients having intraocular retinoblastoma and 2 (0.3%) having metastasis. Patients from low-income countries were diagnosed at a median age of 30.5 months, with 256 of 521 (49.1%) having extraocular retinoblastoma and 94 of 498 (18.9%) having metastasis. Lower national income level was associated with older presentation age, higher proportion of locally advanced disease and distant metastasis, and smaller proportion of familial history of retinoblastoma. Advanced disease at diagnosis

Published
2020

18. The development, testing, and preliminary feasibility of an adaptable pediatric oncology nutrition algorithm for low-middle income countries

Author

Fleming, Cak, Viani, K., Murphy, A., Mosby, T., Arora, B., Schoeman, J., and Ladas, E.

Subjects
Childhood cancer -- Care and treatment, Computational biology -- Innovations, Child nutrition -- Management, Company business management, Health
Abstract

Byline: CAK. Fleming, K. Viani, A. Murphy, T. Mosby, B. Arora, J. Schoeman, E. Ladas Background: Survivors of childhood cancer are at increased risk for several cardiometabolic complications. Obesity/overweight and [...]

Published
2015

19. Nutritional assessment and intervention in a pediatric oncology unit

Author

Schoeman, J.

Subjects
Precision medicine -- Research, Nutritional assessment -- Methods, Childhood cancer -- Care and treatment, Cancer research, Health
Abstract

Byline: J. Schoeman Nutritional status in children with cancer is an important prognostic factor. Assessment consisting of anthropometry, biochemistry, clinical, and diet that needs to be done on diagnosis and [...]

Published
2015

21. Tuberculous hydrocephalus: comparison of different treatments with regard to ICP, ventricular size and clinical outcome

Author

Schoeman, J., Donald, P., Van Zyl, L., Keet, M., and Wait, J.

Subjects
Intracranial pressure -- Complications, Meningitis -- Complications, Mycobacterium tuberculosis, Hydrocephalus -- Care and treatment, Health
Abstract

Tuberculous meningitis (TBM), a swelling of cerebral membranes caused by infection with tubercule bacillus, is relatively rare in industrialized countries, but is widespread elsewhere and has a high mortality rate. Complications include raised intracranial pressure (ICP), which is due to hydrocephalus, or retention of fluid in the brain. In the absence of ways to curtail the incidence of TBM at present, focus has been on treating complications such as ICP. Various therapies have been useful in treating ICP. In the present study, the relative values of oral acetazolamide and furosemide (two drugs combined in treatment), intrathecal hyaluronidase (injection of an enzyme used to dissolve blockages that may contribute to fluid retention), and ventriculoperitoneal shunting (an artificial opening for drainage of fluid) were compared with respect to their ability to induce normal ICP. The subjects were 81 children with raised ICP due to TBM-related hydrocephalus, who were aged five months to eight years, assigned to one of four treatment groups. Group A, with 19 subjects, was a control group treated only for TBM. Group B included 19 children who received injections of hyaluronidase weekly for an average of six weeks, but for no less than four weeks. The 19 children in group C received acetazolamide and furosemide for a minimum of four weeks and an average of six weeks. In group D six children underwent shunting operations. These six children, however, were reassigned to one of the other three groups when the promising results obtained with drug therapy became apparent. Within the first month, 63 percent of the children had normal ICP. The best results were obtained in treatment group B (71 percent) and treatment group C (78 percent). In group A, 41 percent achieved normalized ICP. The average age of successfully treated children was 29 months compared with 41 months for those unsuccessfully treated. Seventy-two percent of those with stage II TBM were successfully treated compared with 40 percent of those with stage III TBM. Other clinical differences associated with patient outcome are discussed as well. The results illustrate the need for early diagnosis and drug therapy for TBM in young children. (Consumer Summary produced by Reliance Medical Information, Inc.)

Published
1991

23. Childhood tuberculosis is associated with decreased abundance of T cell gene transcripts and impaired T cell function

Author

Rottenberg, ME, Hemingway, C, Berk, M, Anderson, ST, Wright, VJ, Hamilton, S, Eleftherohorinou, H, Kaforou, M, Goldgof, GM, Hickman, K, Kampmann, B, Schoeman, J, Eley, B, Beatty, D, Pienaar, S, Nicol, MP, Griffiths, MJ, Waddell, SJ, Newton, SM, Coin, LJ, Relman, DA, Montana, G, Levin, M, Rottenberg, ME, Hemingway, C, Berk, M, Anderson, ST, Wright, VJ, Hamilton, S, Eleftherohorinou, H, Kaforou, M, Goldgof, GM, Hickman, K, Kampmann, B, Schoeman, J, Eley, B, Beatty, D, Pienaar, S, Nicol, MP, Griffiths, MJ, Waddell, SJ, Newton, SM, Coin, LJ, Relman, DA, Montana, G, and Levin, M

Abstract

The WHO estimates around a million children contract tuberculosis (TB) annually with over 80 000 deaths from dissemination of infection outside of the lungs. The insidious onset and association with skin test anergy suggests failure of the immune system to both recognise and respond to infection. To understand the immune mechanisms, we studied genome-wide whole blood RNA expression in children with TB meningitis (TBM). Findings were validated in a second cohort of children with TBM and pulmonary TB (PTB), and functional T-cell responses studied in a third cohort of children with TBM, other extrapulmonary TB (EPTB) and PTB. The predominant RNA transcriptional response in children with TBM was decreased abundance of multiple genes, with 140/204 (68%) of all differentially regulated genes showing reduced abundance compared to healthy controls. Findings were validated in a second cohort with concordance of the direction of differential expression in both TBM (r2 = 0.78 p = 2x10-16) and PTB patients (r2 = 0.71 p = 2x10-16) when compared to a second group of healthy controls. Although the direction of expression of these significant genes was similar in the PTB patients, the magnitude of differential transcript abundance was less in PTB than in TBM. The majority of genes were involved in activation of leucocytes (p = 2.67E-11) and T-cell receptor signalling (p = 6.56E-07). Less abundant gene expression in immune cells was associated with a functional defect in T-cell proliferation that recovered after full TB treatment (p<0.0003). Multiple genes involved in T-cell activation show decreased abundance in children with acute TB, who also have impaired functional T-cell responses. Our data suggest that childhood TB is associated with an acquired immune defect, potentially resulting in failure to contain the pathogen. Elucidation of the mechanism causing the immune paresis may identify new treatment and prevention strategies.

Published
2017

25. Preterm labour - is bacterial vaginosis involved?

Author

Odendaal, HJ, Popov, I, Schoeman, J, Smith, M, and Grove, D

Abstract

Objective. To assess the efficacy of treatment of bacterial vaginosis (BV) using metronidazole to reduce preterm labour in primiravidae and multigravidae with previous midtrimester abortion or preterm labour.Design. Randomised controlled trial.Setting. Tertiary academic hospital.Method. Two different groups of patients were screened for BV at the first antenatal visit, namely primigravidae and high-risk multigravidae who had had a previous midtrimester abortion or preterm delivery. Patients where BV was diagnosed clinically or on Gram's stain of a smear taken from the posterior vaginal fornix, received either 400 mg metronidazole, or 100 mg vitamin C orally twice daily for 2 days. The Gram's stain was repeated after 4 weeks. If BV W?S found again, treatment with the same drug was repeated.Outcome measures. Preterm delivery, birth weight and perinatal deaths.Results. One thousand and five patients entered the study, but 40 were excluded for various reasons and 10 were lost to follow-up. There were 464 primigravidae, of whom 150 (32%) had BV. Except for the 5-minute Apgar score, no significant differences were found between primigravidae negative for BV and those who received either metronidazole or vitamin C. There were 491 high-risk multigravidae, of whom 127 (26%) had BV. The mean gestational age in the BVnegative group was 37 weeks, in contrast to 37.4 weeks in the vitamin C group and 35.6 weeks in the metronidazole group. Birth weights in these three groups were 2 752 g, 2 759 g and 2 475 g respectively, significantly less (P == 0.0109) in the metronidazole group in comparison with the BV-negative group. Delivery before 37 weeks occurred in 29% of high-risk multigravidae with no BV but in 24% of those who took vitamin C and in 43% who took metronidazole. Differences were significant between the BV-negative and metronidazole groups (P = 0.0231) and also between the metrol'.idazole and vitamin C groups (P = 0.0274). Delivery before 28 weeks occurred in 4% of the high-risk multigravidae with no UV but in 10% of those with BV who took metronidazole. The difference was significant (P =0.0430). Analysis for maximum likelihood estimates for preterm labour identified only previous preterm labour or midtrimester abortion as risk factors.Conclusion. Metronidazole does not seem to reduce the prevalence of preterm labour when given for BV before 26 weeks' gestation.

Published
2015

28. Biological Psychiatry Congress 2015

Author

Temmingh, H, primary, Stein, D J, additional, Howells, F M, additional, Botha, U A, additional, Koen, L, additional, Mazinu, M, additional, Jordaan, E, additional, Niehaus, D J H, additional, Burger, A, additional, Brooks, S, additional, Roos, A, additional, Kwiatkowski, M, additional, Donald, K A, additional, Chiliza, B, additional, Asmal, L, additional, Emsley, R, additional, Clark, H M, additional, Du Plessis, Ilse, additional, Du Plessis, S, additional, Vink, M, additional, Joska, J A, additional, Koutsilieri, E, additional, Bagadia, A, additional, Sian, M J, additional, Hemmings, S M J, additional, Martin, L I, additional, Van der Merwe, L, additional, Benecke, R, additional, Domschke, K, additional, Seedat, S, additional, Janse van Rensburg, S, additional, Van Toorn, R, additional, Schoeman, J F, additional, Peeters, A, additional, Fisher, L R, additional, Moremi, K, additional, Kotze, M J, additional, Joubert, P, additional, Lippi, G, additional, Lochner, C, additional, Taljaard, L, additional, Louw, K-A, additional, Phillips, N, additional, Ipser, J, additional, Hoare, J, additional, Malan-Muller, S, additional, Fairbairn, L, additional, Daniels, W M U, additional, Dashti, M J S, additional, Oakeley, E J, additional, Altorfer, M, additional, Harvey, J, additional, Gamieldien, J, additional, Maodi, M L, additional, Rataemande, S T, additional, Kyaw, T, additional, McGregor, N W, additional, Dimatelis, J, additional, Kinnear, C J, additional, Russel, V, additional, and Nortje, G, additional

Published
2015
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33. Oorlog en de media

Author

Weerdenburg, J., Schoeman, J., Groebel, F.J., Wecke, L., Rijs, B., Nieuwenhuis, W., Herben, M., Baar, D.-J. van, and Uricchio, W.C.

Subjects
General
Abstract

Over de rol van de media tijdens oorlogen, conflict- en rampsituaties citeerde NRC Handelsblad op 7 maart 1995 de toenmalige minister van Defensie Joris Voorhoeve: "Pas als televisiecamera's het leed in de huiskamer brengen, komt de internationale gemeenschap op gang". En, zo vervolgde hij ietwat somber: "Dat is vaak te laat". Maar weinig mensen zullen het met deze opvatting van de minister oneens zijn. Immers, voordat de publieke opinie kan worden gemotiveerd hulp te bieden en voordat iiberhaupt kan worden bepaald welke hulp noodzakelijk is, onverschillig of dat bij een natuurramp of een gewapend treffen is, zal er eerst bekendheid aan zo'n gebeurtenis moeten worden gegeven. De rol van de media is daarbij meervoudig: zij confronteren en verbinden het westerse geweten met het lijden in ramp- en oorlogsgebieden, en zij zijn zodoende degene die het menselijk leed dat voortvloeit uit zo'n ramp, ongeluk of oorlog op de publieke agenda plaatsen.

Published
1999

49. THE POSSIBLE INFLUENCE OF RISK MANAGEMENT, FORECASTING, AND PERSONNEL TRAINING IN PHYSICAL ASSET MANAGEMENT.

Author

Schoeman, J. S. and Vlok, P. J.

Subjects
*ASSET management, *RISK management in business, *BUSINESS forecasting, *FINANCIAL planning, *EMPLOYEE training
Abstract

The work presented in this paper highlights the possible effects of risk management, forecasting, and personnel training in the physical asset management environment. Each section is taken separately, and an argument is formed as to why it is important and what portion of the physical asset management five-year budget each should receive. This paper considers the long-term and short-term benefits in its conclusion that risk management should receive 60 per cent of the budget, personnel training 25 per cent, and forecasting the final 15 per cent. [ABSTRACT FROM AUTHOR]

Published
2014
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