Mutualism benefits and the evolution of an interspecific sentry call in associations between Sociable Weavers and Fork-tailed Drongos

Mutualisms, where organisms benefit from cooperation, are common in nature, but payoffs are dynamic and mutualists can incur costs as well as benefits from their association. Nevertheless, selection can favour the coevolution of behaviour that increases benefits. Such coevolution can potentially result in new mutualistic behaviours. Our study considered associations between Fork-tailed Drongos (Dicrurus adsimilis), birds which use both false alarms and aggression to steal food from other species (kleptoparasitism), and their most frequent host, the Sociable Weaver (Philetairus socius). While drongos apparently gain and weavers lose from this association, we investigated whether weavers derive foraging and predator protection benefits, and whether drongos increase foraging opportunities through sentry call behaviour. When with drongos, weavers increased their foraging time and reduced vigilance. Experimental playbacks further demonstrated that drongo sentry calls attract sociable weavers, as well as increasing their foraging time and decreasing their vigilance. Weavers also resumed foraging after an alarm more quickly when sentry calls were made, but sentry calls do not appear to improve drongo false alarm success since sentry calls did not increase the likelihood weavers fled to subsequent drongo false alarms. Consequently sentry calls benefit weavers via foraging payoffs and drongos via weaver attraction and potentially by increasing opportunities for kleptoparasitism. Results demonstrate that despite costly deception between mutualists, individuals nevertheless derive benefits which may be enhanced by the coevolution of a mutually beneficial vocal signal, specific to interspecific communication

Modern management of colorectal cancer

Colorectal cancer affects approximately 1:20 of the population and in South Africa is largely managed by general surgeons. Management of this disease has undergone very significant changes over the last two decades. Until very recently, only two academic general surgery departments included a specialist colorectal unit, and this remains so in the majority of our universities. This has resulted in a generation of surgical graduates who are unfamiliar with, and unskilled in current best management practices for this disease. Rectal cancer is particular challenging and attracts extremely high morbidity and mortality, with poor oncological outcomes. Repeatedly, outcome has been shown to be worse in the hands of generalists, rather than specialist colorectal surgeons, of whom there are very few in the country. This review presents the most important advances of the last 20 years and highlights current controversies and frontiers.Keywords: management, colorectal cance

Surgical convalescence

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Modern management of colorectal cancer

Colorectal cancer affects approximately 1:20 of the population and in South Africa is largely managed by general surgeons. Management of this disease has undergone very significant changes over the last two decades. Until very recently, only two academic general surgery departments included a specialist colorectal unit, and this remains so in the majority of our universities. This has resulted in a generation of surgical graduates who are unfamiliar with, and unskilled in current best management practices for this disease. Rectal cancer is particular challenging and attracts extremely high morbidity and mortality, with poor oncological outcomes. Repeatedly, outcome has been shown to be worse in the hands of generalists, rather than specialist colorectal surgeons, of whom there are very few in the country. This review presents the most important advances of the last 20 years and highlights current controversies and frontiers

An analysis of the financial reporting compliance of South African public agricultural companies

Abstract: This article assesses the extent to which South African public companies that are engaged in agricultural activities are complying with the compulsory recognition and measurement and compulsory and voluntary disclosure requirements of IAS 41 Agriculture. Sixteen large South African public companies with material holdings of biological assets in their statements of financial position were selected for analysis. The results of the analysis show that the majority of South African agricultural companies are using fair value to measure their biological assets at initial recognition as well as at the end of each reporting period. Most of these companies are complying with the compulsory disclosure requirements of IAS 41, and are also providing certain of the recommended voluntary disclosures listed in IAS 41. The study concludes that the measurement methods used by companies to value their biological assets and the nature and extent of both compulsory and voluntary disclosures of these assets are sector-specific. This is consistent with previous research findings. This study contributes to the existing literature by providing a baseline on the financial reporting of agricultural entities in South Africa prior to the implementation of IFRS 13

Examining the relationship between binge eating and coping strategies and the definition of binge eating in a sample of spanish adolescents

The present study had two major goals: to explore the relationship between binge eating and coping strategies in a sample of Spanish adolescents and to examine the adolescents’ concept of binge eating. Two hundred and fifty-nine adolescents from a secondary school completed the Adolescent Coping Scale (ACS; Frydenberg & Lewis, 1993) and the Bulimic Investigatory Test, Edinburgh (BITE; Henderson & Freeman, 1987), as well as additional questions regarding the binge eating episodes. The results show that the adolescents who reported binge eating used more avoidance coping strategies than those who did not engage in this behavior. Adolescents took into account mainly the amount of food eaten when defining a binge with few of them mentioning loss of control in their descriptions. The results of the study have implications for the prevention of this behavior. The development of constructive ways for solving daily problems and coping with stressors may be a possible prevention strategy for this behaviour in adolescence.Este estudio tenía dos objetivos principales: explorar la relación entre los atracones de comida y las estrategias de afrontamiento en una muestra de adolescentes españoles y examinar el concepto que tienen los adolescentes de atracones. Una muestra de 259 adolescentes de una escuela secundaria rellenaron el ACS y el BITE, así como preguntas adicionales sobre los episodios de atracones. Los resultados muestran que los adolescentes que informaban del comportamiento de atracones empleaban más estrategias evitativas de afrontamiento que los que no realizaban este tipo de comportamiento. Al definir un atracón, los adolescentes consideraban principalmente la cantidad de comida consumida y pocos mencionaban la pérdida de control en sus descripciones. Los resultados del estudio tienen implicaciones para la prevención de este comportamiento. El desarrollo de formas constructivas para resolver los problemas cotidianos y afrontar los estresares puede ser una estrategia de prevención de este comportamiento en adolescentes