Today, scientific research on the types of Nexus, especially the water- energy- food Nexus as the driver of improving the welfare of society, is expanding. Since the Nexus approach is relatively new and requires the cooperation of several fields, explaining the concepts, its literature review, with a special focus on the water- energy- food Nexus is essential. This article aims to express Nexus approach simple and clear, by a detailed review of several related articles from 2011 to 2021. Articles were reviewed and categorized by year, source variety, and topic. So the outline of the formation of the Nexus approach, water- energy- food Nexus and the questions raised about this approach were codified in a way that provides a practical insight for policy making. In general, the Nexus approach, especially the water- energy- food Nexus which creates a very complex system and must be considered from a political, social and economic perspective, is difficult to implement. However, the Nexus approach is transitioning to an important component of development planning, and its success requires the guidance of strategic policies and institutional structures in multilevel governance. It seems that countries need to reform their governance structures in line with the Nexus approach. Another issue that has been considered in this article is the difference between the Water- Energy- Food Nexus approach with the approach of integrated water resources management. Due to the similarities, there are doubts about the need to move from integrated water resources management to Water- Energy- Food Nexus.

The approach of water, food and energy nexus is a comprehensive view of sustainability; and agriculture plays a key role in the use of these resources and food security. Considering that the identification of the indicators of the water, food and energy security nexus in the agricultural sector is the main criterion for checking the status of the deployment of these resources in order to establish security in the agricultural sector. The gap in this field has caused this article to compile and evaluate the indicators of the approach of water, food and energy security nexus in the agricultural sector. To achieve this goal, the method of qualitative content analysis was used, using MAXQDA 18 software and manual analysis. The research sample included 228 articles related to the research topic, which were published in national and international journals during the years 2007-2022. The findings showed; Water, food, and energy security have eight, fourteen, and ten indicators, respectively, which were categorized into four categories: access, availability, usability, and sustainability. According to the findings, we conclude that these indicators include the dimensions of sustainable development, including economic, social and environmental dimensions, and are interdependent. Therefore, these indicators are a comprehensive tool to measure the approach of water, food and energy nexus in the direction of sustainable development.

BACKGROUND: During the modification of several races, which has been done on chickens, there have been several changes in the function of neural pathways and receptor density involved in the control of food intake and appetite. Melanocortin system and its receptors are involved in the central regulation of nutritional behaviour and energy balance. Therefore, this study was designed to investigate the role of this system in the central control of food and water intake in birds.OBJECTIVES: The present study aimed to evaluate the role of MCR3 and MCR4 receptors in controlling the food and water intake in birds.METHODS: This work was performed on 48 Ross 308 broiler chicks through two experiments (each experiment in four groups). Primarily, stereotaxic surgical guide cannula was implanted in the chickens. Subsequently, in the first experiment, the chickens were divided into the four following groups: the control solution, 0.2, 2, and 10 nmol/5µl of SHU9119 (Non-selective antagonist of MCR3 and MCR4 receptors) In the second experiment, the chickens were also divided in four groups: the received control solution, 0.2, 2, and 10 nmol/5µl of MCL0020 (Selective MCR4 receptor antagonist) via intracerebroventricular (ICV) injection. Afterwards, cumulative food and water intake were measured at 30, 60, 90, 120, 150, and 180 minutes after the injection.RESULTS: The results of this study showed that ICV injection of SHU9119 and MCL0020 increased cumulative food intake (P>0.05), but did not affect cumulative water intake (P<0.05).CONCLUSIONS: According to the findings herein, central melanocortin system is one of the systems involved in central control of food intake in birds.

Achieving food and water security is one of the most important goals of policymakers in different countries. Water scarcity in Iran could be one of the major food security challenges in the future. For this purpose, climatic zoning was performed using the Domarten method. After calculating the water requirement using CROPWAT software; the amount of virtual water, water footprint, water productivity, volume of water consumed by each crop in each zone and the optimal food gap in different climates were calculated. According to the results; The per capita water footprint of the agricultural sector in hyper-arid, desert arid, semi-arid, Mediterranean and humid climates and Iran is 1611.97, 1228.09, 665.83, 884.01, 600.21 and 998.20cubic meters, respectively. In addition, the intensity of water consumption within the 5 climatic zones and Iran is 64.89, 88.03, 63.19, 41.01, 56.38 and 65.48 %, respectively. Net virtual water imports for each zone show that desert arid and humid zones are exporters of virtual water and hyper-arid, semi-arid and Mediterranean zones are importers of virtual water.The results show a contradiction between the realization of water security and food security in terms of quantity. The results showed that if the goal is to establish water security; by increasing the net import of virtual water (in the case of high-consumption products with low water efficiency), the intensity of pressure on domestic water resources in each area could be reduced. But if the goal is self-sufficiency; If the current situation does not change (crop composition in cropping pattern, yield and irrigation efficiency in each zone), more pressure will be put on water resources. Therefore, in order to achieve the goals of self-sufficiency and water security coefficients at the same time; It is recommended to increase the yield, improve the irrigation efficiency, formulate a suitable cultivation pattern and allocate water resources according to water productivity and its yield in each zone.