Despite the rapidly increasing volume of research on the biological and photochemical degradation of DOC (dissolved organic carbon) in aquatic environments, little is known of the large-scale ...patterns in biologically and photochemically degradable DOC (BDOC and PDOC, respectively) in continental watersheds, and on the links that exist between these two key properties that greatly influence the flow of carbon from continents to oceans. Here we explored the patterns in the concentrations and proportions of BDOC and PDOC across hundreds of boreal lakes, rivers and wetlands spanning a large range of system trophic status and terrestrial influence, and compared the drivers of these two reactive pools of DOC at the landscape level. Using standardized incubations of natural waters, we found that the concentrations of BDOC and PDOC covaried across all systems studied but were nevertheless related to different pools of dissolved organic matter (DOM; identified by fluorescence analyses) in ambient waters. Concentrations of nutrients and protein-like fluorescent DOM (FDOM) explained nearly half of the variation in BDOC, whereas PDOC was exclusively predicted by DOM optical properties, consistent with the photochemical degradability of specific FDOM pools that we experimentally determined. The concentrations of colored DOM (CDOM), which we use here as a proxy of terrestrial influence, almost entirely accounted for the observed relationship between FDOM and the concentrations of both BDOC and PDOC. The concentrations of CDOM and of the putative biolabile fluorescence component shifted from complete decoupling in clear-water environments to strong coupling in darker streams and wetlands. This suggests a baseline autochthonous BDOC pool fueled by internal production that is gradually overwhelmed by land-derived BDOC as terrestrial influence increases across landscape gradients. The importance of land as a major source of both biologically and photochemically degradable DOC for continental watersheds resulted in a partial coupling of those carbon pools in natural freshwaters, despite fundamental contrasts in terms of their composition and regulation.
Dissolved organic matter (DOM) is a master variable in aquatic systems. Modern fluorescence techniques couple measurements of excitation emission matrix (EEM) spectra and parallel factor analysis ...(PARAFAC) to determine fluorescent DOM (FDOM) components and DOM quality. However, the molecular signatures associated with PARAFAC components are poorly defined. In the current study we characterized river water samples from boreal Québec, Canada, using EEM/PARAFAC analysis and ultrahigh resolution mass spectrometry (FTICR-MS). Spearman’s correlation of FTICR-MS peak and PARAFAC component relative intensities determined the molecular families associated with 6 PARAFAC components. Molecular families associated with PARAFAC components numbered from 39 to 572 FTICR-MS derived elemental formulas. Detailed molecular properties for each of the classical humic- and protein-like FDOM components are presented. FTICR-MS formulas assigned to PARAFAC components represented 39% of the total number of formulas identified and 59% of total FTICR-MS peak intensities, and included significant numbers compounds that are highly unlikely to fluoresce. Thus, fluorescence measurements offer insight into the biogeochemical cycling of a large proportion of the DOM pool, including a broad suite of unseen molecules that apparently follow the same gradients as FDOM in the environment.
•Development of hydrogen-fueled yard truck for sustainable mobility in ports.•Design of hybrid powertrain for a heavy-duty vehicle used in port operations.•Assessment of plug-in fuel cell/battery ...hybrid yard truck energy performance.•Vehicle modelling based on real roll-on/roll-off driving and duty cycles.•Efficient energy and power management of the hybrid electric vehicle.
The maritime transport and the port-logistic industry are key drivers of economic growth, although, they represent major contributors to climate change. In particular, maritime port facilities are typically located near cities or residential areas, thus having a significant direct environmental impact, in terms of air and water quality, as well as noise. The majority of the pollutant emissions in ports comes from cargo ships, and from all the related ports activities carried out by road vehicles. Therefore, a progressive reduction of the use of fossil fuels as a primary energy source for these vehicles and the promotion of cleaner powertrain alternatives is in order.
The present study deals with the design of a new propulsion system for a heavy-duty vehicle for port applications. Specifically, this work aims at laying the foundations for the development of a benchmark industrial cargo–handling hydrogen-fueled vehicle to be used in real port operations. To this purpose, an on-field measurement campaign has been conducted to analyze the duty cycle of a commercial Diesel-engine yard truck currently used for terminal ports operations. The vehicle dynamics has been numerically modeled and validated against the acquired data, and the energy and power requirements for a plug-in fuel cell/battery hybrid powertrain replacing the Diesel powertrain on the same vehicle have been evaluated. Finally, a preliminary design of the new powertrain and a rule-based energy management strategy have been proposed, and the electric energy and hydrogen consumptions required to achieve the target driving range for roll-on and roll-off operations have been estimated.
The results are promising, showing that the hybrid electric vehicle is capable of achieving excellent energy performances, by means of an efficient use of the fuel cell. An overall amount of roughly 12 kg of hydrogen is estimated to be required to accomplish the most demanding port operation, and meet the target of 6 h of continuous operation. Also, the vehicle powertrain ensures an adequate all-electric range, which is between approximately 1 and 2 h depending on the specific port operation.
Potentially, the hydrogen-fueled yard truck is expected to lead to several benefits, such as local zero emissions, powertrain noise elimination, reduction of the vehicle maintenance costs, improving of the energy management, and increasing of operational efficiency.
Creativity represents a young and promising academic field of research. Over the last 20 years, creativity publications have been steadily increasing in number. Of the 20 most all-time prolific ...creativity scholars in the European Union (EU), only one has retired. The present paper aims at mapping the EU creativity research. We analyzed over 12,000 Web of Science records dated back to 1968 until December 2020, using two bibliometric tools, SciMAT and VOSviewer. The descriptive analysis lists the most prolific authors and journals on the creativity area, the most cited articles, as well as the authors', institutions', countries', and research areas' bibliometric networks. Moreover, this study presents a thematic analysis and an evolution map of the themes based on keywords. The EU scholars were found to establish collaborations based on geographical, cultural, and, maybe, idiomatic proximity. Engineering, computer science, and education & educational research are the most interconnected areas of research. Innovation, performance, creative cities, the neuroscientific study of creativity, and emotions are relevant topics in the area. A broader concept of the creative and collaborative economy, the impact of technology on developing creativity, and the study of the brain with neuroscientific tools may become promising lines for future research.
Viral infection is thought to play an important role in shaping bacterial community composition and diversity in aquatic ecosystems, but the strength of this interaction and the mechanisms underlying ...this regulation are still not well understood. The consensus is that viruses may impact the dominant bacterial strains, but there is little information as to how viruses may affect the less abundant taxa, which often comprise the bulk of the total bacterial diversity. The potential effect of viruses on the phylogenetic composition of marine bacterioplankton was assessed by incubating marine bacteria collected along a North Pacific coastal-open ocean transect in seawater that was greatly depleted of ambient viruses. The ambient communities were dominated by typical marine groups, including alphaproteobacteria and the Bacteroidetes. Incubation of these communities in virus-depleted ambient water yielded an unexpected and dramatic increase in the relative abundance of bacterial groups that are generally undetectable in the in situ assemblages, such as betaproteobacteria and Actinobacteria. Our results suggest that host susceptibility is not necessarily only proportional to its density but to other characteristics of the host, that rare marine bacterial groups may be more susceptible to viral-induced mortality, and that these rare groups may actually be the winners of competition for resources. These observations are not inconsistent with the 'phage kills the winner' hypothesis but represent an extreme and yet undocumented case of this paradigm, where the potential winners apparently never actually develop beyond a very low abundance threshold in situ. We further suggest that this mode of regulation may influence not just the distribution of single strains but of entire phylogenetic groups.
Over the last 40 years, dissolved organic carbon (DOC) has been increasing in freshwater across many boreal regions. The extent to which these long‐term changes have affected lake CO2 dynamics is ...unclear. We have studied the temporal trends in DOC and pressure of CO2 (pCO2) over 40 years in 15 lakes in two regions of Ontario (Canada) subjected to browning and the abatement of SO2 deposition. Whereas from 1980 to 1999 there were no significant trends in pCO2 in any of the lakes, a significant increase was observed from 2000 to 2017. Although DOC concentrations increased during the same period, pCO2 and DOC were only weakly coupled, and we hypothesize the existence of DOC thresholds that determine this coupling. The recent increases in pCO2, linked to shifts in the C balance of lakes, may be contributing to the observed declines in lake pH, leading to a re‐acidification of lakes.
Plain Language Summary
Over the past decades, terrestrial dissolved organic carbon (DOC) inputs to lakes have been increasing in boreal and northern ecosystems, raising questions about changes in the carbon dynamics of inland waters, especially carbon dioxide (CO2) production. Here we present long‐term trends in pressure of CO2 (pCO2) concurrent with the continuous increase in DOC across 15 lakes in Ontario (Canada). We show that from 1980 to 1999, there were no or few changes in pCO2 trends, but that net increases have been observed from 2000 to 2017 in all the studied lakes. As pCO2 and DOC long‐term trends are weakly coupled, we hypothesized the existence of a DOC threshold needed to stimulate a pCO2 response. We further propose that the contemporary increase in pCO2 has the potential to regulate pH, leading to a re‐acidification of these lakes.
Key Points
Pressure of CO2 (pCO2) remained rather constant in lake surface water in the 80s, but started to increase in the past two decades
Long‐term trends in pCO2 and dissolved organic carbon (DOC) are weakly coupled, despite a constant increase in DOC
Recent changes in pCO2 and DOC may lead to a re‐acidification of inland waters and changes in C balance between burial and emissions
Organic thin-film transistor sensors have been recently attracting the attention of the plastic electronics community for their potential exploitation in novel sensing platforms. Specificity and ...sensitivity are however still open issues: in this respect chiral discrimination-being a scientific and technological achievement in itself--is indeed one of the most challenging sensor bench-tests. So far, conducting-polymer solid-state chiral detection has been carried out at part-per-thousand concentration levels. Here, a novel chiral bilayer organic thin-film transistor gas sensor--comprising an outermost layer with built-in enantioselective properties-is demonstrated to show field-effect amplified sensitivity that enables differential detection of optical isomers in the tens-of-parts-per-million concentration range. The ad-hoc-designed organic semiconductor endowed with chiral side groups, the bilayer structure and the thin-film transistor transducer provide a significant step forward in the development of a high-performance and versatile sensing platform compatible with flexible organic electronic technologies.
Post-operative cognitive dysfunction (POCD) is a debilitating clinical phenomenon in elderly patients. Management of pain in elderly is complicated because analgesic opiates elicit major side ...effects. In contrast, paracetamol (acetaminophen) has shown analgesic efficacy, no impact on cognition, and its side effects are well tolerated. We investigated the efficacy of paracetamol, compared to the opioid analgesic buprenorphine, in a model of POCD by investigating cognitive decline, allodynia, peripheral and hippocampal cytokines levels, and hippocampal microtubule dynamics as a key modulator of synaptic plasticity. A POCD model was developed in middle-aged (MA) rats by inducing a tibia fracture via orthopaedic surgery. Control MA rats did not undergo any surgery and only received isoflurane anaesthesia. We demonstrated that cognitive decline and increased allodynia following surgery was prevented in paracetamol-treated animals, but not in animals which were exposed to anesthesia alone or underwent the surgery and received buprenorphine. Behavioral alterations were associated with different peripheral cytokine changes between buprenorphine and paracetamol treated animals. Buprenorphine showed no central effects, while paracetamol showed modulatory effects on hippocampal cytokines and markers of microtubule dynamics which were suggestive of neuroprotection. Our data provide the first experimental evidence corroborating the use of paracetamol as first-choice analgesic in POCD.
The nitrogen (N) stable isotopic composition of pore water nitrate and total dissolved N (TDN) was measured in sediments of the St. Lawrence Estuary and the Gulf of St. Lawrence. The study area is ...characterized by gradients in organic matter reactivity, bottom water oxygen concentrations, as well as benthic respiration rates. N isotope effects on the water column associated with the benthic exchange of nitrate (εapp) and TDN (εsed) during benthic nitrification-denitrification coupling were investigated. The sediments were a major sink for nitrate and a source of reduced dissolved N (RDN = DON + NH4+). We observed that both the pore water nitrate and RDN pools were enriched in 15N relative to the water column, with increasing δ15N downcore in the sediments. As in other marine environments, the biological nitrate isotope fractionation of net fixed N loss was barely expressed at the scale of sediment-water exchange, with ϵapp values <3‰. The strongest under-expression (i.e. lowest εapp) of the biological N isotope fractionation was observed at the most oxygenated sites with the least reactive organic matter, indicating that, through their control on the depth of the denitrification zone, bottom water oxygen concentrations and the organic matter reactivity can modulate εapp. For the first time, actual measurements of δ15N of pore water RDN were included in the calculations of εsed. We argue that large fractions of the sea-floor-derived DON are reactive and, hence, involved in the development of the δ15N of dissolved inorganic N (DIN) in the water column. In the St. Lawrence sediments, the combined benthic N transformations yield a flux of 15N-enriched RDN that can significantly elevate εsed above εapp. Calculated εsed values were within the range of 4.6 ± 2‰ and were related to organic matter reactivity and oxygen penetration depth in the sediments. ϵsed reflects the δ15N of the N2 lost from marine sediments and thus best describes the isotopic impact of fixed N loss from sediments on the oceanic fixed N pool. Our mean value for εsed is larger than assumed by earlier work, questioning current ideas with regards to the state of balance of the modern N budget.
In the architecture, engineering and construction industry, site management during construction is a key phase. Scheduling activities and monitoring their progress allow any deviations from the ...schedule to be identified so that timely action can be taken. Until now, the monitoring phase has mainly been characterised by inspections in which the construction site manager manually collects data and produces a summary report. This proves to be a time-consuming process and is prone to errors. The authors propose an innovative construction progress monitoring method that combines BIM-based construction scheduling (4D BIM) with periodic geometric surveying using an indoor mobile mapping system (iMMS). Ten surveys were carried out on a real case study, producing point clouds to be compared with the 4D BIM, thereby comparing the as-built with the as-planned. The comparison was carried out using Sitemotion exploiting a custom class, the work breakdown structure (WBS), added to the BIM to associate each element with its scheduled construction date. The results show how the proposed method can effectively support the evaluation of construction progress, allowing the monitoring to be performed digitally and linked to the BIM. The paper details the proposed methodology, highlighting the problems encountered and suggesting adjustments for future implementation.
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