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This is a conference paper. ; This report analyses the political challenge of improving access to sanitation in rapidly growing and developing secondary cities. We look at examples throughout history and across the world, and argue that while sanitation problems may appear to be technical in nature, without political incentives to solve them, progress cannot be made. Drawing on lessons from historical progress, we formulate a framework for understanding how improvements in urban sanitation take place. We then apply these principles to current sanitation challenges in two secondary Tanzanian cities, Mwanza and Arusha, to assess what could drive improvements there, and potentially elsewhere.

The South Sandwich Volcanic Arc is one of the most remote and enigmatic arcs on Earth. Sporadic observations from rare cloudfree satellite images—and even rarer in situ reports—provide glimpses into a dynamic arc system characterised by persistent gas emissions and frequent eruptive activity. Our understanding of the state of volcanic activity along this arc is incomplete compared to arcs globally. To fill this gap, we present here detailed geological and volcanological observations made during an expedition to the South Sandwich Islands in January 2020.We report the first in situ measurements of gas chemistry, emission rate and carbon isotope composition from along the arc. We show that Mt. Michael on Saunders Island is a persistent source of gas emissions, releasing 145±59 t day−1 SO2 in a plume characterised by a CO2/SO2 molar ratio of 1.8 ± 0.2. Combining this CO2/SO2 ratio with our independent SO2 emission rate measured near simultaneously, we derive a CO2 flux of 179 ± 76 t day−1. Outgassing from low temperature (90–100 °C) fumaroles is pervasive at the active centres of Candlemas and Bellingshausen, with measured gas compositions indicative of interaction between magmatic fluids and hydrothermal systems. Carbon isotope measurements of dilute plume and fumarole gases from along the arc indicate a magmatic δ13C of − 4.5 ± 2.0‰. Interpreted most simply, this result suggests a carbon source dominated by mantle-derived carbon. However, based on a carbon mass balance from sediment core ODP 701, we show that mixing between depleted upper mantle and a subduction component composed of sediment and altered crust is also permissible.We conclude that, although remote, the South Sandwich Volcanic Arc is an ideal tectonic setting in which to explore geochemical processes in a young, developing arc. ; This expedition was funded by public donations raised by Quark Expeditions Ltd., by the Government of South Georgia and the South Sandwich Islands (GSGSSI) and by individual contributions. This work was carried out under RAP 2019/025 issued by GSGSSI. EJL was supported by a Leverhulme Early Career Fellowship. A.A. and M.B. acknowledge funding from Miur (Grant N. 2017LMNLAW). K.W. acknowledges support from the Mount Everest Foundation (20-06) ; Published ; id 3 ; 4V. Processi pre-eruttivi ; 6V. Pericolosità vulcanica e contributi alla stima del rischio ; 1IT. Reti di monitoraggio e sorveglianza ; JCR Journal

Over evolutionary time, pathogen challenge shapes the immunepheno type of the host to better respond to an incipient threat. The extent and direction of this selection pressure depend on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local pathogen threats in wild animals. The Gentoo penguin (Pygoscelis papua) is a species complex that lends itself to the study of immune adaptation because of its circumpolar distribution over a large latitudinal range, with little or no admixture between ''different clades. Inthis study, we examine the diversity in a key family of innate immune genes-theToll-like receptors (TLRs)-across the range of the Gentoo penguin. The three TLRs that we investigated present varying levels of diversity, with TLR4 and TLR5 greatly exceeding the diversity of TLR7. We present evidence of positive selection in TLR4 and TLR5, which points to pathogen-driven adaptation to the local pathogen milieu. Finally, we demonstrate that two positively selected cosegregating sites in TLR5 are sufficient to alter the responsiveness of the receptor to its bacterial ligand, flagellin. Taken together, these results suggest that Gentoo penguins have experienced distinct pathogen-driven selection pressures in different environments, which may be important given the role of the Gentoo penguin as a sentinel species in some of the world's most rapidly changing environments. ; Oxford Clarendon Fund scholarship Biotechnology and Biological Sciences Research Council (BBSRC) BB/M011224/1 Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) PIA ACT172065 Spanish Government CGL2007-60369 CTM2015-64720 Institut Polaire Francais Paul-Emile Victor (IPEV: Program 137) Institut Polaire Francais Paul-Emile Victor (IPEV: Program 354) Laboratoire International Associe 647 "BioSensib" (CSM/CNRS-University of Strasbourg) ALS