2,905 research outputs found
Using auxiliary gas power for CCS energy needs in retrofitted coal power plants
Adding post-combustion capture technology to existing coal-fired power plants is being considered as a near-term option for mitigating CO[subscript 2] emissions. To supply the thermal energy needed for CO[subscript 2] capture, much of the literature proposes thermal integration of the existing coal plant’s steam cycle with the capture process’ stripper reboiler. This paper examines the option of using an auxiliary natural gas turbine plant to meet the energetic demands of carbon capture and compression. Three different auxiliary plant technologies were compared to integration for 90% capture from an existing, 500 MW supercritical coal plant. CO[subscript 2] capture (via a monoethylamine (MEA) absorption process) and compression is simulated using Aspen Plus. Thermoflow software is used to simulate three gas plant technologies. In some circumstances, it is found that using an auxiliary natural gas turbine may make retrofits more attractive compared to using thermal integration. The most important factors affecting desirability of the auxiliary plant retrofit are the cost of natural gas, the full cost of integration, and the potential for sale of excess electricity.Research Council of Norway (Statoil (Firm: Norway)Massachusetts Institute of Technology. Carbon Sequestration Initiativ
Mathematical modelling of tissue-engineering angiogenesis
We present a mathematical model for the vascularisation of a porous scaffold following implantation in vivo. The model is given as a set of coupled non-linear ordinary differential equations (ODEs) which describe the evolution in time of the amounts of the different tissue constituents inside the scaffold. Bifurcation analyses reveal how the extent of scaffold vascularisation changes as a function of the parameter values. For example, it is shown how the loss of seeded cells arising from slow infiltration of vascular tissue can be overcome using a prevascularisation strategy consisting of seeding the scaffold with vascular cells. Using certain assumptions it is shown how the system can be simplified to one which is partially tractable and for which some analysis is given. Limited comparison is also given of the model solutions with experimental data from the chick chorioallantoic membrane (CAM) assay
Training pharmacists to deliver a complex information technology intervention (PINCER) using the principles of educational outreach and root cause analysis
Objective:
To describe the training undertaken by pharmacists employed in a pharmacist-led information technology-based intervention study to reduce medication errors in primary care (PINCER Trial), evaluate pharmacists’ assessment of the
training, and the time implications of undertaking the training.
Methods:
Six pharmacists received training, which included training on root cause analysis and educational outreach, to enable them to deliver the PINCER Trial intervention. This was evaluated using self-report questionnaires at the end of each training session. The time taken to complete each session was recorded. Data from the evaluation forms were entered onto a Microsoft Excel spreadsheet, independently
checked and the summary of results further verified. Frequencies were calculated for responses to the three-point Likert scale questions. Free-text comments from the
evaluation forms and pharmacists’ diaries were analysed thematically.
Key findings:
All six pharmacists received 22 hours of training over five sessions. In four out of the five sessions, the pharmacists who completed an evaluation form (27 out
of 30 were completed) stated they were satisfied or very satisfied with the various elements of the training package. Analysis of free-text comments and the pharmacists’
diaries showed that the principles of root cause analysis and educational outreach were viewed as useful tools to help pharmacists conduct pharmaceutical interventions
in both the study and other pharmacy roles that they undertook. The opportunity to undertake role play was a valuable part of the training received.
Conclusions:
Findings presented in this paper suggest that providing the PINCER pharmacists with training in root cause analysis and educational outreach contributed to the successful delivery of PINCER interventions and could potentially be utilised
by other pharmacists based in general practice to deliver pharmaceutical interventions to improve patient safety
Dielasma or Tunethyris? A Taxonomic Conundrum
A new species of a dielasmid brachiopod from the Triassic Saharonim Formation of Makhtesh Ramon, southern Israel, was discovered in Anisian-Ladinian limestones that alternate with calcareous shales. The environment of deposition was an open shelf with normal salinity. The new species is homeomorphic with Paleozoic forms, but may not belong to the genus Dielasma; however, it may be a species of Tunethyris, a Triassic genus from Tunisia. If the Triassic specimens belong to the Paleozoic genus Dielasma, an important new Lazarus genus is added to the systematic literature. However, if the specimens belong to the Triassic Tunethyris, there are important paleobiogeographic considerations to be noted, such as the significance of the enigmatic Ladinian crisis and the influence of the Hispanic Corridor, an immature seaway connecting the western Tethys with eastern Panthalassa that may have been open sporadically during the Late Triassic and affected brachiopod distribution. Points favoring the selection of Tunethyris are: 1. The orientation of the crura in the new species is slightly different from Paleozoic dielasmids, especially D. elongatum from the Permian of Germany; 2. the anatomy of Tunethyris punica from the Norian of Tunisia is very similar to the new species and the anterior commissure of both is sulicplicate, a feature not found in Paleozoic forms; 3. The loop of the Israeli brachiopods is acuminate. In addition to other anatomical characters that support the erection of a new species, Tunethyris calzada has a septalium supported by a median septum whereas the septalium in the brachiopods from Makhtesh Ramon rests on the valve floor
Dynamical orbital evolution scenarios of the wide-orbit eccentric planet HR 5183b
The recently-discovered giant exoplanet HR5183b exists on a wide,
highly-eccentric orbit (\,au, ). Its host star possesses a common
proper-motion companion which is likely on a bound orbit. In this paper, we
explore scenarios for the excitation of the eccentricity of the planet in
binary systems such as this, considering planet-planet scattering, Lidov-Kozai
cycles from the binary acting on a single-planet system, or Lidov-Kozai cycles
acting on a two-planet system that also undergoes scattering. Planet-planet
scattering, in the absence of a binary companion, has a probability
of pumping eccentricities to the observed values in our simulations, depending
on the relative masses of the two planets. Lidov-Kozai cycles from the binary
acting on an initially circular orbit can excite eccentricities to the observed
value, but require very specific orbital configurations for the binary and
overall there is a low probability of catching the orbit at the high observed
high eccentricity (). The best case is provided by planet-planet
scattering in the presence of a binary companion: here, the scattering provides
the surviving planet with an initial eccentricity boost that is subsequently
further increased by Kozai cycles from the binary. We find a success rate of
for currently observing in this set-up. The single-planet
plus binary and two-planet plus binary cases are potentially distinguishable if
the mutual inclination of the binary and the planet can be measured, as the
latter permits a broader range of mutual inclinations. The combination of
scattering and Lidov-Kozai forcing may also be at work in other wide-orbit
eccentric giant planets, which have a high rate of stellar binary companions.Comment: Accepted to MNRAS. A simple board game based on the paper may be
found at http://filestore.astro.lu.se/research/alex/HR5183b.pd
Training pharmacists to deliver a complex information technology intervention (PINCER) using the principles of educational outreach and root cause analysis
Objective To describe the training undertaken by pharmacists employed in a
pharmacist-led information technology-based intervention study to reduce medication
errors in primary care (PINCER Trial), evaluate pharmacists’ assessment of the
training, and the time implications of undertaking the training.
Methods Six pharmacists received training, which included training on root cause
analysis and educational outreach, to enable them to deliver the PINCER Trial intervention.
This was evaluated using self-report questionnaires at the end of each training
session. The time taken to complete each session was recorded. Data from the
evaluation forms were entered onto a Microsoft Excel spreadsheet, independently
checked and the summary of results further verified. Frequencieswere calculated for
responses to the three-point Likert scale questions. Free-text comments from the
evaluation forms and pharmacists’ diaries were analysed thematically.
Key findings All six pharmacists received 22 h of training over five sessions. In four
out of the five sessions, the pharmacists who completed an evaluation form (27 out
of 30were completed) stated theywere satisfied or very satisfiedwith the various elements
of the training package.Analysis of free-text comments and the pharmacists’
diaries showed that the principles of root cause analysis and educational outreach
were viewed as useful tools to help pharmacists conduct pharmaceutical interventions
in both the study and other pharmacy roles that they undertook. The opportunity
to undertake role play was a valuable part of the training received.
Conclusions Findings presented in this paper suggest that providing the PINCER
pharmacists with training in root cause analysis and educational outreach contributed
to the successful delivery of PINCER interventions and could potentially be utilised
by other pharmacists based in general practice to deliver pharmaceutical
interventions to improve patient safety
Discovery of a White Dwarf Companion to HD 159062
We report on the discovery of a white dwarf companion to the nearby late G
dwarf star, HD 159062. The companion is detected in 14 years of precise radial
velocity (RV) data, and in high-resolution imaging observations. RVs of HD
159062 from 2003-2018 reveal an acceleration of ,
indicating that it hosts a companion with a long-period orbit. Subsequent
imaging observations with the ShaneAO system on the Lick Observatory 3-meter
Shane telescope, the PHARO AO system on the Palomar Observatory 5-meter
telescope, and the NIRC2 AO system at the Keck II 10-meter telescope reveal a
faint companion 2.7'' from the primary star. We performed relative photometry,
finding magnitudes,
magnitudes, and magnitudes for the companion from
these observations. Analysis of the radial velocities, astrometry, and
photometry reveals that the combined data set can only be reconciled for the
scenario where HD 159062 B is a white dwarf. A full Bayesian analysis of the RV
and imaging data to obtain the cooling age, mass, and orbital parameters of the
white dwarf indicates that the companion is an old white dwarf with an orbital period of years, and a cooling age of Gyr.Comment: 10 pages, 9 figure
Solution structure of a bacterial microcompartment targeting peptide and its application in the construction of an ethanol bioreactor
Targeting of proteins to bacterial microcompartments (BMCs) is mediated by an 18-amino-acid peptide sequence. Herein, we report the solution structure of the N-terminal targeting peptide (P18) of PduP, the aldehyde dehydrogenase associated with the 1,2-propanediol utilization metabolosome from Citrobacter freundii. The solution structure reveals the peptide to have a well-defined helical conformation along its whole length. Saturation transfer difference and transferred NOE NMR has highlighted the observed interaction surface on the peptide with its main interacting shell protein, PduK. By tagging both a pyruvate decarboxylase and an alcohol dehydrogenase with targeting peptides, it has been possible to direct these enzymes to empty BMCs in vivo and to generate an ethanol bioreactor. Not only are the purified, redesigned BMCs able to transform pyruvate into ethanol efficiently, but the strains containing the modified BMCs produce elevated levels of alcohol
IVF or ICSI for fertility preservation?
In IVF, eggs and sperm are added together for fertilisation to occur whereas ICSI involves injecting a single sperm into each egg. ICSI is very effective where sperm count or swimming is poor (male infertility) but is slightly riskier than IVF in terms of health problems in children, although these risks are small. However, the risk of no eggs fertilising is higher for IVF compared to ICSI and couples undertaking fertility preservation, for example, before cancer treatment, usually only have time for one attempt. Using fertility preservation treatment cycle data reported to Human Fertilisation and Embryology Authority (HFEA), this study shows that ICSI results in higher number of fertilised eggs and embryos for storage or treatment compared to IVF. However, 19% of eggs are not used in ICSI treatment, so IVF appears to be better overall. Clinics should choose IVF or ICSI for fertility preservation depending on sperm characteristics rather than using ICSI for all
Dendrochronological dating of coal mine workings at the Joggins Fossil Cliffs, Nova Scotia, Canada
Joggins, Nova Scotia was one of the first places in North America where coal was mined. In this paper we employ dendrochronology to date timber pit props preserved within relic coal mine workings on the closely adjacent Fundy and Dirty seams. These remains comprise a system of adits created through ‘room and pillar’ mining. Of the seventy-three samples collected, forty-eight were successfully cross-dated against a local red spruce (Picea rubens Sarg.) master chronology thereby establishing the year in which each individual sample was cut as a live tree. Results indicate cut dates of 1849-1875 which are generally consistent with written archival records of mining activity on these coal seams. Our analysis of fourteen separate adits allows us to distinguish two phases of mining. Most adits (numbers 1-9 and 11-12 with cut dates of 1849-1868) are relics of an initial operation by the General Mining Association (1865-1871), which opened a mine entered at beach level. Dendrochronological dates preceding the opening of this mine may suggest that timber stockpiled from the nearby Joggins Mine (opened 1847) was used in its construction. The remaining adits (numbers 10 and 13-14 with cut dates of 1873-1875) are probably relics of a later mine opened by the Joggins Coal Mining Company (1872-1877). Although this mine was centered ~500 m inland, its western peripheral workings passed through the earlier workings to the shore. Findings improve knowledge of the industrial archaeology of the UNESCO World Heritage Site and help refine the regional master red spruce chronology for future dendrochronological studies
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