Tubular carbonate concretions as hydrocarbon migration pathways? Examples from North Island, New Zealand

Cold seep carbonate deposits are associated with the development on the sea floor of distinctive chemosyn¬thetic animal communities and carbonate minerali¬sation as a consequence of microbially mediated anaerobic oxidation of methane. Several possible sources of the methane exist, identifiable from the carbon isotope values of the carbonate precipitates. In the modern, seep carbonates can occur on the sea floor above petroleum reservoirs where an important origin can be from ascending thermogenic hydrocar¬bons. The character of geological structures marking the ascent pathways from deep in the subsurface to shallow subsurface levels are poorly understood, but one such structure resulting from focused fluid flow may be tubular carbonate concretions. Several mudrock-dominated Cenozoic (especially Miocene) sedimentary formations in the North Island of New Zealand include carbonate concretions having a wide range of tubular morphologies. The concretions are typically oriented at high angles to bedding, and often have a central conduit that is either empty or filled with late stage cements. Stable isotope analyses (δ13C, δ18O) suggest that the carbonate cements in the concretions precipitated mainly from ascending methane, likely sourced from a mixture of deep thermogenic and shallow biogenic sources. A clear link between the tubular concretions and overlying paleo-sea floor seep-carbonate deposits exists at some sites. We suggest that the tubular carbonate concretions mark the subsurface plumbing network of cold seep systems. When exposed and accessible in outcrop, they afford an opportunity to investigate the geochemical evolution of cold seeps, and possibly also the nature of linkages between subsurface and surface portions of such a system. Seep field development has implications for the characterisation of fluid flow in sedimentary basins, for the global carbon cycle, for exerting a biogeochemical influence on the development of marine communities, and for the evaluation of future hydrocarbon resources, recovery, and drilling and production hazards. These matters remain to be fully assessed within a petroleum systems framework for New Zealand’s Cenozoic sedimentary basins

Stock assessment of the Queensland east coast common coral trout (Plectropomus leopardus) fishery. April 2019

Queensland’s common coral trout (Plectropomus leopardus), a species of grouper, is a line caught fish forming a single population (stock) across the Great Barrier Reef (GBR). Common coral trout are protogynous hermaphrodites (born female, many later changing sex to male) and aggregate to spawn during spring and summer. They can grow to 5 kg and 18 years of age. The stock extends north from the GBR into the eastern Torres Strait where it is under Commonwealth jurisdiction. In financial year 2017-18, the Queensland jurisdiction accounted for around 90% of the total harvest. From 2013-14 to 2017-18, the Queensland total harvest averaged 983 tonnes (t) per year. The catch breakdown is 82% commercial (806 t) and 18% recreational (177 t). The previous stock assessment estimated that in July 2012 the stock was at 60% of unfished biomass (i.e. before fishing began) over the areas commonly fished by commercial fishers. This stock assessment updates the existing model to cover the full extent of the GBR in Queensland waters and includes harvest information from the recreational sector. This stock assessment used a spatial age-structured model with a yearly time step based on financial years. The model considered twelve spatial sub-populations (“strata”) of fish based primarily on differences in coral reef habitat. The model incorporated data spanning the period from 1961-62 to 2017-18 (including commercial harvest (1988-89 to 2017-18); historical commercial (1961-62 to 1981-82); recreational harvest (1996-1997 to 2013-14); age monitoring (1994-95 to 2004-05); and underwater visual surveys (1982-83 to 2017-18)). The purpose of this report is to estimate biological reference points. The model provides estimates of the level of biomass of common coral trout relative to unfished levels, maximum sustainable yield (MSY) and the yield consistent with a biomass ratio of 68% (a proxy for maximum economic yield in this fishery)

Assessment of an ICU-specific, electronic medical summary tool against traditional dictation to reduce communication gaps during ICU-to-inpatient transitions-in-care

  Background: Transition from the intensive care unit (ICU) to an inpatient unit is a vulnerable period where communication gaps between medical teams may be associated with preventable adverse events. The transition-in-care (TIC) summary encompasses essential clinical information and facilitates seamless continuity of patient care between sending and receiving healthcare teams. Yet, current dictation practices often produce summaries of suboptimal quality that result in delayed or incomplete information. An electronic TIC summary tool, an alternative method to dictation, standardizes information, which may ensure more timely and complete communication to reduce information breakdowns and delays. Objective: In order to standardize information communicated during ICU-to-inpatient transitions, an ICU-specific, electronic TIC summary tool was implemented in four adult ICUs in the Calgary zone. It is hypothesized that implementation of the electronic summary will improve completeness and timelines of TIC summaries.  Methods: A multiple baseline study design was used to evaluate the implementation of the electronic TIC summary. ICUs continued dictation practices for a baseline period, until the electronic tool was implemented sequentially (in a randomized order) to each ICU and evaluated for six months following implementation. Post-implementation, providers had the option to dictate or use the electronic summary. The primary outcome was a binary measure of both completeness of four critical elements and availability of the TIC summary at ICU release. Results: Preliminary results were obtained for two months of baseline (n=48) and post-implementation (n=48) from one ICU. Post-implementation summaries contained four critical elements and were more frequently available at ICU transfer than pre-implementation dictations (73% versus 2%, p<0.001). More post implementation summaries contained completion of essential information (median 88% versus 63%, p<0.001) and had greater availability during transition (90% versus 73%, p=0.04) than pre-implementation dictations. With data collection scheduled to end in June 2019, we anticipate full study results to be available fall 2019. Conclusions: Preliminary results post-implementation suggest greater completion and faster availability for the receiving clinicians. It is anticipated that full study findings will add to the current literature on the effect of computerized tools for reducing communication gaps between ICU and inpatient units during transitions-in-care to ultimately improve patient safety

Controlled rotary motion of light-driven molecular motors assembled on a gold film

Using circular dichroism (CD) spectroscopy, we show that light-driven rotary molecular motors based on overcrowded alkenes can function in a self-assembled monolayer on semi-transparent gold films.

MHz Unidirectional Rotation of Molecular Rotary Motors

A combination of cryogenic UV-vis and CD spectroscopy and transient absorption spectroscopy at ambient temperature is used to study a new class of unidirectional rotary molecular motors. Stabilization of unstable intermediates is achieved below 95 K in propane solution for the structure with the fastest rotation rate, and below this temperature measurements on the rate limiting step in the rotation cycle can be performed to obtain activation parameters. The results are compared to measurements at ambient temperature using transient absorption spectroscopy, which show that behavior of these motors is similar over the full temperature range investigated, thereby allowing a maximum rotation rate of 3 MHz at room temperature under suitable irradiation conditions

Stock assessment of the Australian east coast grey mackerel (Scomberomorus semifasciatus) fishery.

This stock assessment used an age structured model with a yearly time step and age based selectivity to estimate the population size and sustainable harvest limits for Queensland east coast grey mackerel. Separate models were assessed for the north-east and south-east stocks. Data inputs included total harvest, standardised catch rates, age and length structures. For both stocks, unfished biomass was relative to 1960-61, before substantial fishing pressure began.   For the north-east stock, model results suggested that biomass declined to 46 per cent unfished, exploitable biomass in 2010-11. The assessment suggests that the north-east stock is currently between 37 and 58 per cent unfished biomass.   For the south-east stock the results suggest that biomass declined to 38 per cent unfished biomass in 2010-11. The assessment suggests that the south-east stock is currently between 40 and 61 per cent of unfished biomass

Stock assessment of Queensland east coast school mackerel (Scomberomorus queenslandicus).

There has been no previous stock assessment for school mackerel. This stock assessment used an age structured model with a yearly time step and length based selectivity. Only the south-east stock was considered for assessment as harvests for the north-east stock were small. Data inputs included total harvest, standardised catch rates and age and length structures. The south-east coast stock model uses data from the 1988-89 to 2017-18 fishing years (comprising commercial harvest (1988-89 to 2017-18); recreational harvest (1994-95 to 2013-14); length structures (2014-15 to 2017-18) and age-length information (1991-92 to 1994-95)). Model analyses suggested that biomass declined from the mid-2000s to around 65% of unfished biomass in 2017-18. Maximum sustainable yield (MSY) was estimated at 104–119 t per year, and the yield consistent with a biomass ratio of 60% was estimated at 84–95 t. The time series of harvests modelled may be underrepresented, causing an overestimate of the biomass ratio. Results reflect a low level of confidence, and precautionary interpretations are warranted