Stress-dependent elastic properties of shales: measurement and modeling

Despite decades of research, current understanding of elastic properties of shales is insufficient as it is based on a limited number of observations caused by the time-consuming nature of testing resulting from their low permeability. Though it is well known that shales are highly anisotropic and assumed to be transversely isotropic (TI) media, few laboratory experiments have been carried out for measuring the five elastic constants that define TI media on well-preserved shales. Many previous measurements were made without control of pore pressure, which is crucial for the determination of shale elastic properties

An estimation of sonic velocities in shale using clay and silt fractions from the elemental capture spectroscopy log

Anisotropic differential effective medium approach is used to simulate elastic properties of shales from elastic properties and volume fractions of clay and silt constituents. Anisotropic elastic coefficients of the wet clay pack are assumed to be independent of mineralogy and to be linearly dependent on clay packing density (CPD), a fraction of clay in an individual wet clay pack. Simulated compressional and shear velocities normal to the bedding plane and are shown to be in a good agreement with measured sonic velocities. Further, elastic coefficients of shales, and, calculated from the log sonic velocities, calibrated porosity and clay fraction obtained from the mineralogy tool are used to invert for elastic constants of clays, C33 and C44. The obtained elastic coefficients of clays show lower scatter than the original elastic coefficients of shales. The noticeable increase of the clay elastic coefficients with the depth increase is shown to result from the positive trend of the CPD with depth. Being interpolated to the same CPD = 0.8, elastic coefficients of clays show no depth dependency. Our findings show that the CPD and silt fraction are the key parameters that can be used for successful modelling of elastic properties of shales

Successful treatment of feline leishmaniosis using an association of allopurinol and N-methyl-glucamine antimoniate

This work describes the diagnosis and successful treatment of a 2-year-old domestic cat infected with Leishmania species and presenting fever, and ulcerative and nodular skin lesions after being treated for pyodermatitis for 1 year without clinical improvement. After anamnesis the cat was submitted to a complete clinical examination. Blood was collected for determination of haematological and biochemical parameters, detection of feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV), feline coronavirus (FCoV) and Leishmania amastigotes. Fine-needle aspiration puncture from the skin nodules was also performed. After definitive diagnosis the animal was treated and followed up over a 2 year period. The animal tested negative for FIV-specific antibodies, FeLV antigen and feline coronavirus RNA. Leishmania amastigotes in the skin nodules were confirmed by cytology and molecular diagnosis. Treatment was initiated with allopurinol, resulting in a slight clinical improvement. Thus, N-methyl-glucamine antimoniate was added and administered for 30 days, with complete closure of the ulcerative lesions in the hindlimbs requiring a surgical approach. Close monitoring of the patient in the following 24 months indicated that combined therapy was safe and clinical cure was achieved without further relapses or side effects.publishersversionpublishe

The Values of Tangible User Interfaces: How to discover, assess and evaluate them?

Since the introduction of Tangible User Interfaces, in the beginning of the 90s, a generation grew up interacting with computers. At the same time the context of computing changed dramatically: from a device used almost exclusively by specialists, it evolved to a general device that plays a dominant role in our societies. But where does this leave TUI? In many respects, the idea of tangibility plays a marginal role in Human Computer Interaction. It makes sense to re-evaluate the intrinsic values of TUI design. This paper proposes to research the appropriate metrics to do so

Informational needs of general practitioners regarding discharge medication: content, timing and pharmacotherapeutic advice

textabstractObjective: To investigate the needs of Dutch general practitioners on discharge medication, both regarding content, timing and the appreciation of pharma-cotherapeutic advices from clinical pharmacists. Setting: A general teaching hospital in Amsterdam, the Netherlands. Method: A prospective observational study was performed. A questionnaire with regard to the content, optimal timing (including way of information transfer) and appreciation of pharmacotherapeutic advices was posted to 464 general practitioners. One reminder was sent. Main outcome measure: Description of the needs of general practitioners was assessed. For each question and categories of comments frequency tables were made. The Fisher-exact test was used to study associations between the answers to the questions. Results: In total, 149 general practitioners (32%) responded. Most general practitioners (75%) experienced a delay in receiving discharge medication information and preferred to receive this on the day of discharge. GPs wished to receive this information mainly through e-mail (44%). There was a significant correlation (P = 0.002) between general practitioners who wanted to know whether and why medication had been stopped (87%) and changed (88%) during hospital admission. The general practitioners (88%) appreciated pharmacotherapeutic advices from clinical pharmacists. Conclusion: This study indicates how information transfer on discharge medication to GPs can be optimised in the Netherlands. The information arrives late and GPs want to be informed on the day of discharge mainly by e-mail. GPs wish to know why medication is changed or discontinued and appreciate pharmacotherapeutic advices from clinical pharmacists

The effect of a clinical pharmacist discharge service on medication discrepancies in patients with heart failure

Objective: Heart failure patients are regularly admitted to hospital and frequently use multiple medication. Besides intentional changes in pharmacotherapy, unintentional changes may occur during hospitalisation. The aim of this study was to investigate the effect of a clinical pharmacist discharge service on medication discrepancies and prescription errors in patients with heart failure. Setting: A general teaching hospital in Tilburg, the Netherlands. Method: An open randomized intervention study was performed comparing an intervention group, with a control group receiving regular care by doctors and nurses. The clinical pharmacist discharge service consisted of review of discharge medication, communicating prescribing errors with the cardiologist, giving patients information, preparation of a written overview of the discharge medication and communication to both the community pharmacist and the general practitioner about this medication. Within 6 weeks after discharge all patients were routinely scheduled to visit the outpatient clinic and medication discrepancies were measured. Main outcome measure: The primary endpoint was the frequency of prescription errors in the discharge medication and medication discrepancies after discharge combined. Results: Forty-four patients were included in the control group and 41 in the intervention group. Sixty-eight percent of patients in the control group had at least one discrepancy or prescription error against 39% in the intervention group (RR 0.57 (95% CI 0.37-0.88)). The percentage of medications with a discrepancy or prescription error in the control group was 14.6% and in the intervention group it was 6.1% (RR 0.42 (95% CI 0.27-0.66)). Conclusion: This clinical pharmacist discharge service significantly reduces the risk of discrepancies and prescription errors in medication of patients with heart failure in the 1st month after discharge

Isoprene hotspots at the Western Coast of Antarctic Peninsula during MASEC′16

Isoprene (C5H8) plays an important role in the formation of surface ozone (O3) and the secondary organic aerosol (SOA) which contributed to the climate change. This study aims to determine hourly distribution of tropospheric isoprene over the Western Coast of Antarctic Peninsula (WCAP) during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC′16). In-situ measurements of isoprene were taken using a custom-built gas chromatography with photoionization detector, known as iDirac. Biological parameters such as chlorophyll a (chl-a) and particulate organic carbon (POC) were compared to the in-situ isoprene measurements. Significant positive correlation was observed between isoprene and POC concentrations (r2 = 0.67, p < 0.001), but not between isoprene and chl-a. The hotspots of isoprene over maritime Antarctic were then were investigated using NAME dispersion model reanalysis. Measurements showed that isoprene mixing ratio were the highest over region of King George Island, Deception Island and Booth Island with values of ∼5.0, ∼0.9 and ∼5.2 ppb, respectively. Backward trajectory analysis showed that air masses may have lifted the isoprene emitted by marine algae. We believe our findings provide valuable data set of isoprene estimation over the under sampled WCAP

Exploring the coupled ocean and atmosphere system with a data science approach applied to observations from the Antarctic Circumnavigation Expedition

The Southern Ocean is a critical component of Earth's climate system, but its remoteness makes it challenging to develop a holistic understanding of its processes from the small scale to the large scale. As a result, our knowledge of this vast region remains largely incomplete. The Antarctic Circumnavigation Expedition (ACE, austral summer 2016/2017) surveyed a large number of variables describing the state of the ocean and the atmosphere, the freshwater cycle, atmospheric chemistry, and ocean biogeochemistry and microbiology. This circumpolar cruise included visits to 12 remote islands, the marginal ice zone, and the Antarctic coast. Here, we use 111 of the observed variables to study the latitudinal gradients, seasonality, shorter-term variations, geographic setting of environmental processes, and interactions between them over the duration of 90ĝ€¯d. To reduce the dimensionality and complexity of the dataset and make the relations between variables interpretable we applied an unsupervised machine learning method, the sparse principal component analysis (sPCA), which describes environmental processes through 14 latent variables. To derive a robust statistical perspective on these processes and to estimate the uncertainty in the sPCA decomposition, we have developed a bootstrap approach. Our results provide a proof of concept that sPCA with uncertainty analysis is able to identify temporal patterns from diurnal to seasonal cycles, as well as geographical gradients and "hotspots"of interaction between environmental compartments. While confirming many well known processes, our analysis provides novel insights into the Southern Ocean water cycle (freshwater fluxes), trace gases (interplay between seasonality, sources, and sinks), and microbial communities (nutrient limitation and island mass effects at the largest scale ever reported). More specifically, we identify the important role of the oceanic circulations, frontal zones, and islands in shaping the nutrient availability that controls biological community composition and productivity; the fact that sea ice controls sea water salinity, dampens the wave field, and is associated with increased phytoplankton growth and net community productivity possibly due to iron fertilisation and reduced light limitation; and the clear regional patterns of aerosol characteristics that have emerged, stressing the role of the sea state, atmospheric chemical processing, and source processes near hotspots for the availability of cloud condensation nuclei and hence cloud formation. A set of key variables and their combinations, such as the difference between the air and sea surface temperature, atmospheric pressure, sea surface height, geostrophic currents, upper-ocean layer light intensity, surface wind speed and relative humidity played an important role in our analysis, highlighting the necessity for Earth system models to represent them adequately. In conclusion, our study highlights the use of sPCA to identify key ocean-atmosphere interactions across physical, chemical, and biological processes and their associated spatio-temporal scales. It thereby fills an important gap between simple correlation analyses and complex Earth system models. The sPCA processing code is available as open-access from the following link: https://renkulab.io/gitlab/ACE-ASAID/spca-decomposition (last access: 29 March 2021). As we show here, it can be used for an exploration of environmental data that is less prone to cognitive biases (and confirmation biases in particular) compared to traditional regression analysis that might be affected by the underlying research question