Conflicts about water in Lake Chad: are environmental, vulnerability and security issues linked?

This paper builds on the growing literature that explores the relations between environmental change and non-traditional security, defined as non-military threats that challenge the survival and well-being of peoples and states. The Lake Chad basin in Africa is used as a case study for analysis. Focusing on a set of questions that has dominated recent theoretical debates, the paper investigates if conflicts resulting from water scarcity are as much about the broader vulnerability of the Lake Chad region as they are about changes in the Lake system and its environment. It argues that conflict is a probable outcome only in locations that are already challenged by a multitude of other context-specific factors beside resource scarcity. In the Lake Chad context, the likelihood of scarcity-driven conflict depends on whether vulnerability increases or decreases in the face of a declining water supply. The paper provides perspectives for a nuanced understanding of how the receding Lake Chad has led to conflict and outlines an integrated, forward-looking research agenda for linking environmental change, vulnerability and security issues in integrated human-environment systems

Cholangiocytes act as Facultative Liver Stem Cells during Impaired Hepatocyte Regeneration

After liver injury, regeneration occurs through self-replication of hepatocytes. In severe liver injury, hepatocyte proliferation is impaired - a feature of human chronic liver disease. It is unclear whether other liver cell types can regenerate hepatocytes. Here we use two independent systems to impair hepatocyte proliferation during liver injury to evaluate the contribution of non-hepatocytes to parenchymal regeneration. First, loss of β1-integrin in hepatocytes with liver injury triggered a ductular reaction of cholangiocyte origin, with approximately 25% of hepatocytes being derived from a non-hepatocyte origin. Second, cholangiocytes were lineage traced with concurrent inhibition of hepatocyte proliferation by β1-integrin knockdown or p21 overexpression, resulting in the significant emergence of cholangiocyte-derived hepatocytes. We describe a model of combined liver injury and inhibition of hepatocyte proliferation that causes physiologically significant levels of regeneration of functional hepatocytes from biliary cells

Twenty-three unsolved problems in hydrology (UPH) – a community perspective

This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through on-line media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focussed on process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come

Groundwater quality: Global threats, opportunities and realising the potential of groundwater

Groundwater is a critical resource enabling adaptation due to land use change, population growth, environmental degradation, and climate change. It can be a driver of change and adaptation, as well as effectively mitigate impacts brought about by a range of human activities. Groundwater quality is key to assessing groundwater resources and we need to improve our understanding and coverage of groundwater quality threats if we are to use groundwater sustainably to not further burden future generations by limiting resources and/or increasing treatment or abstraction costs. Good groundwater quality is key to progress on a range of Sustainable Development Goals, but achievement of those goals most affected by groundwater contamination is often hindered by of a lack of resources to enable adaptation. A range of threats to groundwater quality exist, both natural and anthropogenic, which may constrain groundwater use. However, groundwater often provides good quality water for a range of purposes and is the most important water resource in many settings. This special issue explores some of the key groundwater quality challenges we face today as well as the opportunities good groundwater quality and treatment solutions bring to enhance safe groundwater use. Legacy anthropogenic contaminants and geogenic contaminants may be well documented in certain places, such as N America, Europe and parts of Asia. However, there is a real issue of data accessibility in some regions, even for more common contaminants. This paucity of information can restrict our understanding and ability to manage and protect groundwater sources. Compared to surface water quality, large scale assessments for groundwater quality are still scarce and often rely on inadequate data sets. Better access to existing data sets and more research is needed on many groundwater quality threats. Identification and quantification of these threats will support the wise use and protection of this subsurface resource, allow society to adequately address future challenges, and help communities realise the full potential of groundwater

A Comprehensive Evaluation of Mutual Information Analysis Using a Fair Evaluation Framework

Abstract. The resistance of cryptographic implementations to side channel analysis is matter of considerable interest to those concerned with information security. It is particularly desirable to identify the attack methodology (e.g. di erential power analysis using correlation or distance-of-means as the distinguisher) able to produce the best results. Attempts to answer this question are complicated by the many and varied factors contributing to attack success: the device power consumption characteristics, an attacker's power model, the distinguisher by which measurements and model predictions are compared, the quality of the estimations, and so on. Previous work has delivered partial answers for certain restricted scenarios. In this paper we assess the e ectiveness of mutual information analysis within a generic and comprehensive evaluation framework. Complementary to existing work, we present several notions/characterisations of attack success, as well as a means of indicating the amount of data required by an attack. We are thus able to identify scenarios in which mutual information o ers performance advantages over other distinguishers. Furthermore we observe an interesting feature unique to the mutual information based distinguisher resembling a type of stochastic resonance, which could potentially enhance the e ectiveness of such attacks over other methods in certain noisy scenarios