An approach to identify urban groundwater recharge

Evaluating the proportion in which waters from different origins are mixed in a given water sample is relevant for many hydrogeological problems, such as quantifying total recharge, assessing groundwater pollution risks, or managing water resources. Our work is motivated by urban hydrogeology, where waters with different chemical signature can be identified (losses from water supply and sewage networks, infiltration from surface runoff and other water bodies, lateral aquifers inflows, ...). The relative contribution of different sources to total recharge can be quantified by means of solute mass balances, but application is hindered by the large number of potential origins. Hence, the need to incorporate data from a large number of conservative species, the uncertainty in sources concentrations and measurement errors. We present a methodology to compute mixing ratios and end-members composition, which consists of (i) Identification of potential recharge sources, (ii) Selection of tracers, (iii) Characterization of the hydrochemical composition of potential recharge sources and mixed water samples, and (iv) Computation of mixing ratios and reevaluation of end-members. The analysis performed in a data set from samples of the Barcelona city aquifers suggests that the main contributors to total recharge are the water supply network losses (22%), the sewage network losses (30%), rainfall, concentrated in the non-urbanized areas (17%), from runoff infiltration (20%), and the Besòs River (11%). Regarding species, halogens (chloride, fluoride and bromide), sulfate, total nitrogen, and stable isotopes (<sup>18</sup>O, <sup>2</sup>H, and <sup>34</sup>S) behaved quite conservatively. Boron, residual alkalinity, EDTA and Zn did not. Yet, including these species in the computations did not affect significantly the proportion estimations

Efficacy of Colistin versus β-Lactams, Aminoglycosides, and Rifampin as Monotherapy in a Mouse Model of Pneumonia Caused by Multiresistant Acinetobacter baumannii

The treatment of life-threatening infections due to carbapenem-resistant Acinetobacter baumannii has become a serious challenge for physicians worldwide. Often, only colistin shows in general good in vitro activity against these carbapenem-resistant strains, but its antibacterial efficacy in comparison with the antibiotics most used in clinical practice is not well known. We studied the efficacy of colistin versus those of imipenem, sulbactam, tobramycin, and rifampin in an experimental pneumonia model with immunocompetent mice. We used three strains of A. baumannii corresponding to the main clones (A, D, and E) involved in the outbreaks of our hospital, with different grades of resistance to imipenem (imipenem MICs of 1, 8, and 512 μg/ml, respectively) and to the other antibiotics. The MIC of colistin was 0.5 μg/ml for the three strains. Reduction of log(10) CFU/g in lung bacterial counts, clearance of bacteremia, and survival versus results with controls were used as parameters of efficacy. Imipenem and sulbactam (Δlung counts: −5.38 and −4.64 log(10) CFU/ml) showed the highest level of bactericidal efficacy in infections by susceptible and even intermediate strains. Tobramycin and rifampin (−4.16 and −5.15 log(10) CFU/ml) provided good results against intermediate or moderately resistant strains, in agreement with killing curves and pharmacodynamics. On the contrary, colistin showed the weakest antibacterial effect among the antibiotics tested, both in killing curves and in the in vivo model (−2.39 log(10) CFU/ml; P < 0.05). We conclude that colistin did not appear as a good option for treatment of patients with pneumonia due to carbapenem-resistant A. baumannii strains. Other alternatives, including combinations with rifampin, may offer better therapeutic profiles and thus should be studied

Modulation of Immune Signaling and Metabolism Highlights Host and Fungal Transcriptional Responses in Mouse Models of Invasive Pulmonary Aspergillosis

Abstract Incidences of invasive pulmonary aspergillosis, an infection caused predominantly by Aspergillus fumigatus, have increased due to the growing number of immunocompromised individuals. While A. fumigatus is reliant upon deficiencies in the host to facilitate invasive disease, the distinct mechanisms that govern the host-pathogen interaction remain enigmatic, particularly in the context of distinct immune modulating therapies. To gain insights into these mechanisms, RNA-Seq technology was utilized to sequence RNA derived from lungs of 2 clinically relevant, but immunologically distinct murine models of IPA on days 2 and 3 post inoculation when infection is established and active disease present. Our findings identify notable differences in host gene expression between the chemotherapeutic and steroid models at the interface of immunity and metabolism. RT-qPCR verified model specific and nonspecific expression of 23 immune-associated genes. Deep sequencing facilitated identification of highly expressed fungal genes. We utilized sequence similarity and gene expression to categorize the A. fumigatus putative in vivo secretome. RT-qPCR suggests model specific gene expression for nine putative fungal secreted proteins. Our analysis identifies contrasting responses by the host and fungus from day 2 to 3 between the two models. These differences may help tailor the identification, development, and deployment of host- and/or fungal-targeted therapeutics

Dynamics of persistent colonisation by Haemophilus influenzae in chronic obstructive pulmonary disease patients under long-term treatment with azithromycin

Trabajo presentado en el 29th European Congress of Clinical Microbiology and Infectious Diseases (ESCMID), celebrado en Amsterdam (Países Bajos), del 13 al 16 de abril de 201

ROVs and AUVs

The most significant breakthroughs in science are often made as a result of technological developments and innovation. A new capacity to gather more data, measure more precisely or make entirely new observations generally leads to new insights and fundamental understanding. The future of ocean research and exploration therefore lies in robotics: marine robotic systems can be deployed at depths and in environments that are out of direct reach for humans, they can work around the clock, and they can be autonomous, freeing up time and money for other activities. To advance the field of submarine geomorphology, the two types of robots that currently make the biggest difference are Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs). Other autonomous or robotic systems are available for marine research (e.g. gliders, autonomous surface vehicles, benthic crawlers etc.), but their application for geomorphological studies is less extensive. This chapter gives an overview of the main characteristics of ROVs and AUVs, their advantages and disadvantages, and their main applications for geomorphological research. In comparison to the other geomorphological methods discussed in this book, however, it has to be made clear that ROVs and AUVs are not so much methods per se, instead they are platforms from which existing and new approaches can be applied

Occurrence of Living Cold-Water Corals at Large Depths Within Submarine Canyons of the Northwestern Mediterranean Sea

14 pagesIn the northwestern Mediterranean Sea, cold-water corals Madrepora oculata, Lophelia pertusa, Dendrophyllia cornigera and Desmophyllum dianthus have been mostly described at relatively shallow depths (i.e. <400 m). Here, we report the results of the inspection of the large, deeply incised Cap de Creus, La Fonera and Blanes submarine canyons in order to assess the presence of cold-water corals at depths between 600 and 1500 m. Two complementary methodologies were applied: remotely operated vehicle dives for in situ observation, and Agassiz trawls to get biological samples. Remotely operated vehicle videos pictured aggregations of specimens of the solitary D. dianthus at 1409 m depth in La Fonera Canyon, which seemed to be alive. This is the first in situ observation of this species at such depths in the northwestern Mediterranean Sea. Agassiz trawl samples provided living M. oculata and L. pertusa in Blanes Canyon at 1200 and 900 m depth, respectively. They also yielded living D. dianthus in Cap de Creus Canyon at 900 m and in Blanes Canyon at 900 and 1200 m depth. Jointly with other recently published results, our findings demonstrate that submarine canyons in the northwestern Mediterranean Sea host significant cold-water coral populations, locally extending to water depths below 1000