Turnover time of fluorescent dissolved organic matter in the dark global ocean

Research articleMarine dissolved organic matter (DOM) is one of the largest reservoirs of reduced carbon on Earth. In the dark ocean (4200 m), most of this carbon is refractory DOM. This refractory DOM, largely produced during microbial mineralization of organic matter, includes humic-like substances generated in situ and detectable by fluorescence spectroscopy. Here we show two ubiquitous humic-like fluorophores with turnover times of 435±41 and 610±55 years, which persist significantly longer than the B350 years that the dark global ocean takes to renew. In parallel, decay of a tyrosine-like fluorophore with a turnover time of 379±103 years is also detected. We propose the use of DOM fluorescence to study the cycling of resistant DOM that is preserved at centennial timescales and could represent a mechanism of carbon sequestration (humic-like fraction) and the decaying DOM injected into the dark global ocean, where it decreases at centennial timescales (tyrosine-like fraction).Versión del editor10,015

Effect of marine heat waves on carbon metabolism, optical characterization, and bioavailability of dissolved organic carbon in coastal vegetated communities

Dissolved organic carbon (DOC) plays an essential role in the global marine carbon cycle, with coastal vegetated communities as important DOC producers. However, the ultimate fate of this DOC remains still largely unknown due to the lack of knowledge about its chemical composition and lability. Furthermore, global change could alter both DOC fluxes and its bioavailability, affecting the carbon sequestration capacity of coastal vegetated communities. This study explores, in two contrasting seasons (winter and summer), the effects of an in situ simulated marine heatwave on carbon metabolism and DOC fluxes produced by seagrass (Cymodocea nodosa) and macroalgae (Caulerpa prolifera) communities. In addition, the fluorescent characteristics and biodegradability of the dissolved organic matter released directly by the communities under such conditions are evaluated. Under marine heatwave conditions, a significant increase in net community production (NCP) in C. nodosa and a shift to negative DOC fluxes in C. prolifera were observed. In control treatments, the seagrass-dominated community produced a substantial amount of labile (between 44% and 58%) and recalcitrant DOC (between 42% and 56%), while C. prolifera community produced mainly recalcitrant DOC (between 64% and 87%). Therefore, this research revealed that temperature is an important factor determining the NCP in benthic communities and the chemical structure and bioavailability of DOC produced by these communities, since both communities tended to produce more humic-like and less bioavailable DOC with increasing temperature. © 2022 The Authors. Limnology and Oceanography published by Wiley Periodicals LLC on behalf of Association for the Sciences of Limnology and Oceanography

Evolution of adherence to antiretroviral treatment in a spanish hospital during 2001, 2005 and 2008

The aim of this study was to analyze the evolution of adherence to highly active antiretroviral therapy (HAART) in the Hospital General Universitario Gregorio Marañón (Madrid, Spain) over the last 8 years and determine the variables associated with the complexity of treatment and suboptimal adherence. An observational, retrospective method was used to measure adherence during the first 6 months of HAART in 3 cohorts: 2001 cohort (n = 90), 2005 cohort (n = 98), and 2008 cohort (n = 110). The adherence rate was determined using 2 methods: Pharmacy Department dispensation records and virologic response data. The evolution of the complexity of treatment and its influence on the adherence rate was analyzed by logistic regression. Adherence to HAART increased progressively from 45.6 % in 2001 to 56.1 % in 2005 and 77.3 % in 2008. Statistically significant differences were only observed between cohorts in 2005 and 2008. The average daily pill burden was 7, 4, and 4.5 tablets, respectively. The percentage of patients on twice-daily regimens decreased from 93.3 % in 2001 to 63.6 % in 2008, with a parallel increase in once-daily regimens. The proportion of patients with dietary restrictions decreased from 24.4 % to 3.6 %. A statistically significant association was found between the number of medication units per day and adherence and between frequency of administration and adherence. Adherence to HAART has improved significantly in the last 8 years. While the complexity of the treatment was significantly reduced in 2005, the largest increase in adherence occurred in the last cohort, which shows the influence of factors other than treatment simplification.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Pioneres de les profunditats

La nostra relació amb l’oceà és més estreta del que ens pensem: l’oceà ens alimenta, absorbeix l’excés de gasos d’efecte d’hivernacle i de calor, captura carboni, i és també una font perenne d’inspiració artística. El consens sobre la importància de la seva conservació és indubtable. En aquesta taula rodona conversem amb dones pioneres que s’han endinsat en les profunditats oceàniques i que ens expliquen els resultats de les seves experiències submarines. L’oceanògrafa Cristina Romera dialoga amb l’apneista i fotògrafa japonesa Ai Futaki i amb la microbiòloga Isabel Ferrera, una de les poques persones que ha descendit a 2.600 metres de profunditat a bord de l’Alvin, el submarí que va descobrir les restes del Titanic. El diàleg ofereix, també, una radiografia de l’estat actual dels oceansPeer reviewe

Electrolyte Gated Synaptic Transistor based on an Ultra‐Thin Film of La0.7Sr0.3MnO3

Abstract Developing electronic devices capable of reproducing synaptic functionality is essential in the context of implementing fast, low‐energy consumption neuromorphic computing systems. Hybrid ionic/electronic three‐terminal synaptic transistors are promising as efficient artificial synapses since they can process information and learn simultaneously. In this work, an electrolyte‐gated synaptic transistor is reported based on an ultra‐thin epitaxial La0.7Sr0.3MnO3 (LSMO) film, a half‐metallic system close to a metal‐insulator transition. The dynamic control of oxygen composition of the manganite ultra‐thin film with voltage pulses applied through the gate terminal allows reversible modulation of its electronic properties in a non‐volatile manner. The conductance modulation can be finely tuned with the amplitude, duration, and number of gating pulses, providing different alternatives to gradually update the synaptic weights. The transistor implements essential synaptic features such as excitatory postsynaptic potential, paired‐pulse facilitation, long‐term potentiation/depression of synaptic weights, and spike‐time‐dependent plasticity. These results constitute an important step toward the development of neuromorphic computing devices leveraging the tunable electronic properties of correlated oxides, and pave the way toward enhancing future device functionalities by exploiting the magnetic (spin) degree of freedom of the half metallic transistor channel

Electrolyte gated synaptic transistor based on an ultra-thin film of La0.7Sr0.3MnO3

Developing electronic devices capable of reproducing synaptic functionality is essential in the context of implementing fast, low-energy consumption neuromorphic computing systems. Hybrid ionic/electronic three-terminal synaptic transistors are promising as efficient artificial synapses since they can process information and learn simultaneously. In this work, an electrolyte-gated synaptic transistor is reported based on an ultra-thin epitaxial La0.7Sr0.3MnO3 (LSMO) film, a half-metallic system close to a metal-insulator transition. The dynamic control of oxygen composition of the manganite ultra-thin film with voltage pulses applied through the gate terminal allows reversible modulation of its electronic properties in a non-volatile manner. The conductance modulation can be finely tuned with the amplitude, duration, and number of gating pulses, providing different alternatives to gradually update the synaptic weights. The transistor implements essential synaptic features such as excitatory postsynaptic potential, paired-pulse facilitation, long-term potentiation/depression of synaptic weights, and spike-time-dependent plasticity. These results constitute an important step toward the development of neuromorphic computing devices leveraging the tunable electronic properties of correlated oxides, and pave the way toward enhancing future device functionalities by exploiting the magnetic (spin) degree of freedom of the half metallic transistor channel.Unión EuropeaMinisterio de Ciencia e Innovación (España)Depto. de Física de MaterialesFac. de Ciencias FísicasTRUEpu

Fluorescent dissolved organic matter in the dark ocean

2012 ASLO Aquatic Sciences Meeting: Voyages of Discovery, 8-13 July 2012, Lake Biwa, Shiga, JapanA dissolved organic matter (DOM) fraction absorbs ultraviolet and visible radiation that partially also emits fluorescence when irradiated with ultraviolet light. To identify the most relevant fluorophores present in deep waters, 429 excitation-emission matrixes (EEMs) from the bathypelagic layer of the Atlantic, Indian and Pacific oceans were recorded during the Malaspina 2010 circumnavigation. Parallel factor analysis (PARAFAC) modeling was applied and two humic-like fluorophores were identified in the dominant water masses of the deep world ocean: Antarctic Intermediate Water (AAIW), Circumpolar Deep Water (CDW), North Atlantic Deep Water (NADW) and Pacific Deep Water (PDW). Significant positive relationships were found between the humic-like fluorophores and AOU, suggesting the transformation of colorless bioavailable organic matter into chromophoric refractory DOM (RDOM) through microbial respiration. The RDOM/AOU ratio, a proxy to the efficiency of RDOM production, depended on the water mass. In the particular case of the NADW, terrestrial and in situ produced humic-like fluorophores were differentiated. These results will provide a basis for a better understanding of the role of microbial activity in the origin and fate of marine chromophoric dissolved organic matterPeer Reviewe