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In this paper, we consider the determinant evaluation of a generalized comrade matrix based on a novel incomplete block-diagonalization approach which transforms the determinant of the original generalized comrade matrix into the determinants of tridiagonal matrices and comrade matrix with lower-order. Then, a breakdown-free recursive algorithm for computing the determinant of the generalized comrade matrix is proposed. Even though the algorithm is not a symbolic algorithm, it never suffers from breakdown. Furthermore, we propose an explicit formula for the determinant of the generalized comrade matrix with quasi-Toeplitz structure. Some numerical results with simulations in MATLAB implementation are provided to demonstrate the accuracy and effectiveness of the proposed algorithm, and its competitiveness with MATLAB built-in function.

An article in the July/August 2022 issue (Havenga et al., S Afr J Sci. 2022;118(7/8), Art. #13118) argued that changing the date of the Comrades Marathon from May to August would result in increased heat stress for participants. Heat stress was estimated using the Universal Thermal Climate Index (UTCI), which is designed to represent a person walking, not running. In this Commentary, I argue that using the UTCI may lead to an underestimation of heat stress for the Comrades Marathon, and that the conclusion that August has worse heat stress than May depends on the assumptions in the estimation of heat stress.

We value comments on our research paper in a Commentary in this issue (Simpson, S Afr J Sci. 2024;120(1/2), Art. #16445). Acknowledging the Universal Thermal Comfort Index (UTCI)'s limitations in capturing individual physiological responses remains important; however, we argue for its appropriateness based on recent thermophysiology and heat exchange advancements during its development and broader alignment with standardised indexing efforts. Our original research paper set out with these considerations in mind, and our conclusions remain valid. We further argue for refinement of the UTCI for specific activities instead of using the PET. Finally, future efforts should focus on monitoring data in real-world scenarios to validate and improve thermal indices.

The existing literature on labour movements notes how trade unions have been weakened in recent years. This observable pattern is not unique to South Africa; arguably, this decline represents a global phenomenon characterised by the disintegration of erstwhile militant labour movements. In the case of South Africa, the post-apartheid neoliberal labour regime has fragmented the militant social-movement unionism (SMU) of the 1980s almost to the point of extinction. Despite this trend, various studies have detailed pockets of revival and resistance by workers spread across a variety of sectors and continents. My article seeks to contribute to this literature by drawing on the case study of Mamelodi Train Sector (MTS). MTS was formed in 2001 as a 'mobilising structure', aligned to the African National Congress (ANC) and its alliance partners. Using the notion of space as a theoretical tool, I attempt to understand MTS and the space it organises - the train. MTS utilises the travel time spent going to and from work to offer legislative education to largely unorganised/non-unionised workers. In addition to legislative education, MTS members (self-styled comrades) discuss community issues and matters pertaining to the ANC's tripartite alliance as an attempt to foster a particular kind of identity politics. The data collected reveals that, among other contributions, MTS offers hope and a sense of solidarity to those workers without workplace representation. The comradely sense of belonging, buttressed by a common identity, potentially mitigates the impact of workplace fragmentation - experienced by the majority of workers in South Africa. Organising on the train points to one missing link in our current efforts to understand workers' agency - the geography of transport in South Africa and its related possibilities as a site of revival. With a specific focus on the MTS as a case study, I suggest that the train, as a by-product of apartheid spatiality, represents a strategic location for worker organisation in South Africa.

The Poropuntius tawarensis fish is an endemic fish of the family Cyprinidae found in Laut Tawar Lake, and has been listed on the Red List. This study aims to reveal the frequency of length distribution, growth patterns and condition factors of the fish in the lake as basic information for conservation. The study was conducted from January to May 2022 in the Laut Tawar Lake of Central Aceh. Sampling was conducted at four sampling sites based on representative activities on the lake. The location of the study was determined based on differences in environmental characteristics, namely Station 1 (Teluk One-One), Station 2 (Bewang), Station 3 (Gegarang) and Station 4 (Kebayakan). The results showed that the fish at Bewang Station was relatively higher in terms of the frequency of the length distribution. The growth pattern of male and female fish was negative allometric (b<3).The condition factor of the three stations was relatively the same ranging from 0.94 to 1.39, but it was different from the one-one station with a condition factor of 0.01.The value of the condition factor that can be obtained had insignificant differences every month, namely 1.12±0.38 (January), 1.00±0.49 (February), 0.93±0.55 (March), 0.85±0.59 (April), and 1.17±0.32 (May).

Simpson comments on the article by Havenga et al on the date changes for the Comrades Marathon from May to August which may result in increased heat stress for participants. He argues that using the UTCI may lead to an underestimation of heat stress for the Comrades Marathon, and that the conclusion that August has worse heat stress than May depends on the assumptions in the estimation of heat stress.

The Comrades Marathon is South Africa's - and the world's - most recognised and largest ultra-marathon event, with over 15 000 par ticipants from across the globe competing in the 89-km road running event each year. Historically, the event has been held before the star t of austral winter (20 May - 17 June). However, in 2022, organisers of the race moved the event to 28 August, when austral spring commences. We explore the climate, in par ticular the Universal Thermal Comfor t Index (UTCI), of past Comrades events (1980-2019) and compare these data to UTCI data of the new proposed date (28 August) for the same period. The climatology for May, June, July and August was determined to identify periods with the lowest risk for 'strong' to 'very strong' heat stress. Results show that par ticipants' risk of exposure to 'strong' heat stress and 'very strong' heat stress periods will be more likely if the event is held in August as compared to the original event dates. Therefore, it is concluded that mid-June to mid-July has the lowest risk of heat stress exposure along the route. Runners and organisers should be aware of the higher risk of exer tional heat illness during the 2022 Comrades Marathon to ensure safe par ticipation.

This brief essay meditates on the advent of the ideal of horizontal social relations, exemplified in the early CCP years in the political term, “comrade” (tongzhi). It takes up Qu Qiubai as exemplary of a Marxist political thinker whose commitments to horizontality/comrade relations can be illustrated through his theories of literature, translation and language. It proposes that despite Xi Jinping's recent rhetorical admonishments to re-activate “comrade” as a political term, it is the LGBTQ community's appropriation of “comrade” in contemporary China that actually holds the potential for a substantive reanimation of the utopian ideals begun a century ago.

We value comments on our research paper in a Commentary in this issue (Simpson, S Afr J Sci. 2024;120(1/2), Art. #16445). Acknowledging the Universal Thermal Comfort Index (UTCI)'s limitations in capturing individual physiological responses remains important; however, we argue for its appropriateness based on recent thermophysiology and heat exchange advancements during its development and broader alignment with standardised indexing efforts. Our original research paper set out with these considerations in mind, and our conclusions remain valid. We further argue for refinement of the UTCI for specific activities instead of using the PET. Finally, future efforts should focus on monitoring data in real-world scenarios to validate and improve thermal indices.