Predictive simulation of the water-energy-food nexus for the City of Cape Town.

The City of Cape Town (CoCT), South Africa faced a critical situation between 2015 and 2018 in which the municipal water supply was almost completely exhausted. This situation, commonly referred to as Day Zero in South Africa emanated from a decline in rainfall, resulting in one of the most severe droughts in history. The crisis was also aggravated by rapid population growth and urbanization. CoCT was on the verge of becoming the first city in the past decade to experience a complete cessation of water supply for urban and agricultural purposes. In addition to the effects of low rainfall and population surge, urban energy consumption and increased food demand impacted directly the available water resources. To evaluate the interlinkages between water utilization, water production, energy supply and demand, and food production and demand, this study employed a system dynamics modeling (SDM) approach. The model was developed as a stock and flow diagram utilizing Stella Architect and encompassed five interconnected nodes: water, energy, food, land, and population. The findings revealed that by the end of the 20-year modeling period, the volume of accessible and stored water in all the major dams will be approximately 459 million cubic meters, with residential use accounting for about 85 % of urban water use and agriculture accounting for approximately30.37 % of total water demand. The model illustrates the impacts of precipitation rate, runoff, and evaporation on variables such as land-use change and population dynamics. It is anticipated that the outcomes of this study will serve as valuable inputs for decision-making processes, not only within the CoCT as it aims to mitigate or prevent the recurrence of Day Zero, but also for other cities facing similar challenges.

Onconeuronal cerebellar degeneration-related antigen, Cdr2, is strongly expressed in papillary renal cell carcinoma and leads to attenuated hypoxic response.

The onconeuronal cerebellar degeneration-related antigen Cdr2 is associated with paraneoplastic syndromes. Neoplastic expression of Cdr2 in ovary and breast tumors triggers an autoimmune response that suppresses tumor growth by developing tumor immunity, but culminates in cerebellar degeneration when Cdr2-specific immune cells recognize neuronal Cdr2. We identified Cdr2 as a novel interactor of the hypoxia-inducible factor (HIF) prolyl-4-hydroxylase PHD1 and provide evidence that Cdr2 might represent a novel important tumor antigen in renal cancer. Strong Cdr2 protein expression was observed in 54.2% of papillary renal cell carcinoma (pRCC) compared with 7.8% of clear-cell RCC and no staining was observed in chromophobe RCC or oncocytoma. High Cdr2 protein levels correlated with attenuated HIF target gene expression in these solid tumors, and Cdr2 overexpression in tumor cell lines reduced HIF-dependent transcriptional regulation. This effect was because of both attenuation of hypoxic protein accumulation and suppression of the transactivation activity of HIF-1alpha. pRCC is known for its tendency to avascularity, usually associated with a lower pathological stage and higher survival rates. We provide evidence that Cdr2 protein strongly accumulates in pRCC, attenuates the HIF response to tumor hypoxia and may become of diagnostic importance as novel renal tumor marker.