Unobscured quasars (QSOs) are predicted to be the final stage in the evolutionary sequence from gas-rich mergers to gas-depleted, quenched galaxies. Studies of this population, however, find a high incidence of far-infrared-luminous sources-suggesting significant dust-obscured star formation-but direct observations of the cold molecular gas fuelling this star formation are still necessary. We present a NOEMA study of CO(2-1) emission, tracing the cold molecular gas, in ten lensed z = 1-1.5 unobscured QSOs. We detected CO(2-1) in seven of our targets, four of which also show continuum emission (λ_rest = 1.3 mm). After subtracting the foreground galaxy contribution to the photometry, spectral energy distribution fitting yielded stellar masses of 10^9-11 M_⊙, with star formation rates of 25-160 M_⊙ yr^-1 for the host galaxies. These QSOs have lower L′_CO than star-forming galaxies with the same LIR, and show depletion times spanning a large range (50-900 Myr), but with a median of just 90(α_CO/4) Myr. We find molecular gas masses in the range ≤2-40 × 10⁹(α_CO/4) M_⊙, which suggest gas fractions above ~50% for most of the targets. Despite the presence of an unobscured QSO, the host galaxies are able to retain significant amounts of cold gas. However, with a median depletion time of ~90 Myr, the intense burst of star formation taking place in these targets will quickly deplete their molecular gas reservoirs in the absence of gas replenishment, resulting in a quiescent host galaxy. The non-detected QSOs are three of the four radio-loud QSOs in the sample, and their properties indicate that they are likely already transitioning into quiescence. Recent cosmological simulations tend to overestimate the depletion times expected for these z ~ 1 QSO-host galaxies, which is likely linked to their difficulty producing starbursts across the general high-redshift galaxy population.

Urban areas are facing challenges for the provision of public services, with water scarcity arising as one of the main problems. A twin track approach of supply and demand management is essential, and water-loss management contributes to reducing water demand. However, small municipalities from developing countries have technical, information, and financial limitations to locate and monitor water losses. This paper presents the estimation of real and apparent losses in a small municipality from a developing country in a data-scarce situation. For this, several tools were used, allowing data integration that resulted in a water balance, from which water losses were estimated at 46%, and four alternatives for water-loss reduction were developed. A cost-benefit analysis and financial indicators were estimated for the proposed alternatives, resulting in a water savings of 19%, a payback period of 3 years and an internal rate of return of 39%. The proposed strategies have potential to improve water quantity and quality, the technical stability of the system, utility performance, and water security.