688 research outputs found

    Geodynamically consistent inferences on the uniform sampling of Earth's paleomagnetic inclinations

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    Paleomagnetism is a key method to reconstruct the Earth's paleogeography and thus essential for understanding tectonic evolution, but it assumes that the Earth's magnetic field structure has always averaged to a geocentric axial dipole (GAD). The GAD hypothesis may be tested using the observed inclination frequency distribution, but only if continents sampled all of the Earth's latitudes uniformly, which is not known. Here, we provide new insight into the uniform sampling problem by employing a suite of 3D spherical mantle convection models that feature the self-consistent evolution of mantle convection, plate tectonics and continental drift over timescales of 2 Gyr or more. Our results suggest that continents unlikely sampled latitudes uniformly during the Phanerozoic, consistent with previous suggestions. This finding is robust for a variety of geodynamic evolutions with different mantle and lithosphere structures, at least in the absence of true polar wander. For longer sampling durations, uniform sampling typically becomes more feasible, but may only be achieved with confidence after time scales of minimum 1.3 Gyr. This time scale depends on the structure of the mantle and lithosphere and may be shortest when upper mantle viscosity is small such that reduced resistive drag at the cratonic base allows for faster continental drift. Weak plates (low plastic yield strength) promote more dispersed continent configurations, which tends to facilitate uniform sampling. If these conditions are not met, the uniform sampling time scale can easily exceed several billion years. Even the minimum estimate of 1.3 Gyr challenges the validity of using the Phanerozoic inclination frequency distribution to infer the past average magnetic field structure; the approach could however still be applicable using the Precambrian inclination record. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe

    Physical properties of 368 meteorites: Implications for meteorite magnetism and planetary geophysics

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    Petrophysical studies (susceptibility, intensity of natural remanent magnetisation (NRM) and dry bulk density) of 368 meteorites are reviewed together with magnetic hysteresis data for 50 achondrites and chondrites. The relationships between dry bulk density, metallic FeNi-content and porosity will be discussed in the case of L-chondrites. Using the petrophysical classification scheme the meteorite class and the petrologic group of a sample can be determined in most of the cases providing a rapid means for determining a preliminary classification of a new sample. In addition, the petrophysical database provides a direct source of basic physical properties of the small bodies in the solar system. Paleointensity determinations with Thellier technique will be presented for 16 meteorites representing different chondrite groups. The results yield high paleofield values ranging from 51μT to 728μT for the magnetically hardest meteorites consistent with previous studies. However, these values must be looked with caution, because of possible physico-chemical or mineralogical alterations during heating

    Experiences of Using Models and Information of Building Automation System in Commissioning

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    Simulation programs are widely used in the design of heating and cooling devices. However, modeling of the whole building with simulation programs is exceptional at least in Finland. We have built and utilized whole building models in a commissioning project to estimate the energy consumption and the indoor climate in an educational building. We have also used component models in the commissioning of a ventilation system. One of our pilots was modeled very accurately using IDA-ICE. Finnish engineering office Granlund LTD has modeled the same building with a simulation program called RIUSKA, which is based on DOE-2. We present an analysis based on verification results of simulation to measured energy consumption, and the results of component models to the actual properties of HVAC system

    Neutrophil activation in septic acute kidney injury : A post hoc analysis of the FINNAKI study

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    Background Inflammation, reflected by high plasma interleukin-6 concentration, is associated with acute kidney injury (AKI) in septic patients. Neutrophil activation has pathophysiological significance in experimental septic AKI. We hypothesized that neutrophil activation is associated with AKI in critically ill sepsis patients. Methods We measured plasma (n = 182) and urine (n = 118) activin A (a rapidly released cytosolic neutrophil protein), interleukin-8 (a chemotactic factor for neutrophils), myeloperoxidase (a neutrophil biomarker released in tissues), and interleukin-6 on intensive care unit admission (plasma and urine) and 24 hours later (plasma) in sepsis patients manifesting their first organ dysfunction between 24 hours preceding admission and the second calendar day in intensive care unit. AKI was defined by the Kidney Disease: Improving Global Outcomes criteria. Results Plasma admission interleukin-8 (240 [60-971] vs 50 [19-164] pg/mL, P <.001) and activin A (845 [554-1895] vs 469 [285-862] pg/mL, P <.001) were but myeloperoxidase (169 [111-300] vs 144 [88-215] ng/mL, P = .059) was not higher among patients with AKI compared with those without. Urine admission interleukin-8 (50.4 [19.8-145.3] vs 9.5 [2.7-28.7] ng/mL, P <.001) and myeloperoxidase (7.7 [1.5-12.6] vs 1.9 [0.4-6.9] ng/mL, P <.001) were but activin A (9.7 [1.4-42.6] vs 4.0 [0.0-33.0] ng/mL, P = .064) was not higher in AKI than non-AKI patients. Urine myeloperoxidase correlated with urine interleukin-8 (R = .627, P <.001) but not with plasma myeloperoxidase (R = .131, P = .158). Conclusion Interleukin-8 in plasma and urine was associated with septic AKI. Elevated plasma activin A indicates intravascular neutrophil activation in septic AKI. Concomitant plasma and urine myeloperoxidase measurements suggest neutrophil accumulation into injured kidneys.Peer reviewe

    Antimicrobial resistance in Staphylococcus spp., Escherichia coli and Enterococcus spp. in dogs given antibiotics for chronic dermatological disorders, compared with non-treated control dogs

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    The aim of this study was to evaluate antimicrobial resistance in canine staphylococci, Escherichia coli and enterococci, which were isolated from 22 dogs with pyoderma and a history of previous antibiotic treatment, compared to bacterial isolates from 56 non-treated control dogs. Two isolates of each bacterial species per dog were investigated, if detected. Staphylococcal isolates from dogs with pyoderma (35 isolates) were more resistant to sulphatrimethoprim than the isolates from controls (56 isolates) (57% vs. 25%, p < 0.004). Multiresistance in staphylococci was also more common in dogs with pyoderma (29% vs. 9%, p = 0.02). A similar trend among isolates of E. coli was detected (24 and 74 isolates from treated and control dogs, respectively), but the differences were not significant. Resistance for macrolide-lincosamides was approximately 20% among staphylococci in both groups. Resistance to ampicillin among enterococci was 4%–7%. The age of the dogs might have an impact on resistance: multiresistance among staphylococcal isolates from younger dogs (≤5 years) was more common than in older dogs (≥6 years) (24%, vs. 0%, 63 and 27 isolates, respectively, p = 0.02). Staphylococci in younger dogs were more resistant to tetracycline (48% vs. 11%, p < 0.001) and sulphatrimethoprim (48% vs. 15%, p < 0.01) than those in older dogs. In contrast, the isolates of E. coli from older dogs tended to be more resistant, although a significant difference was detected only in resistance to tetracycline (13% vs. 2% of 40 and 50 isolates respecthely, p = 0.04)). The results of this small study indicate that resistance in canine staphylococci in the capital area of Finland is comparable with many other countries in Europe. Resistance in indicator bacteria, E. coli and enterococci, was low

    Urine NGAL as a biomarker for septic AKI : a critical appraisal of clinical utility-data from the observational FINNAKI study

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    Background: Neutrophil gelatinase-associated lipocalin (NGAL) is released from kidney tubular cells under stress as well as from neutrophils during inflammation. It has been suggested as a biomarker for acute kidney injury (AKI) in critically ill patients with sepsis. To evaluate clinical usefulness of urine NGAL (uNGAL), we post-hoc applied recently introduced statistical methods to a sub-cohort of septic patients from the prospective observational Finnish Acute Kidney Injury (FINNAKI) study. Accordingly, in 484 adult intensive care unit patients with sepsis by Sepsis-3 criteria, we calculated areas under the receiver operating characteristic curves (AUCs) for the first available uNGAL to assess discrimination for four outcomes: AKI defined by Kidney Disease: Improving Global Outcomes (KDIGO) criteria, severe (KDIGO 2-3) AKI, and renal replacement therapy (RRT) during the first 3 days of intensive care, and mortality at day 90. We constructed clinical prediction models for the outcomes and used risk assessment plots and decision curve analysis with predefined threshold probabilities to test whether adding uNGAL to the models improved reclassification or decision making in clinical practice. Results: Incidences of AKI, severe AKI, RRT, and mortality were 44.8% (217/484), 27.7% (134/484), 9.5% (46/484), and 28.1% (136/484). Corresponding AUCs for uNGAL were 0.690, 0.728, 0.769, and 0.600. Adding uNGAL to the clinical prediction models improved discrimination of AKI, severe AKI, and RRT. However, the net benefits for the new models were only 1.4% (severe AKI and RRT) to 2.5% (AKI), and the number of patients needed to be tested per one extra true-positive varied from 40 (AKI) to 74 (RRT) at the predefined threshold probabilities. Conclusions: The results of the recommended new statistical methods do not support the use of uNGAL in critically ill septic patients to predict AKI or clinical outcomes.Peer reviewe

    Removal of ammonium from wastewater with geopolymer sorbents fabricated via additive manufacturing

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    Geopolymers have been recently explored as sorbents for wastewater treatment, thanks to their mechanical and chemical stability and to their low-energy manufacturing process. One specific application could be the removal of ammonium (NH4+) through exchange with Na+ ions. Additive manufacturing (AM) represents an especially interesting option for fabrication, as it allows to tailor the size, distribution, shape, and interconnectivity of pores, and therefore the access to charge-bearing sites. The present study provides a proof of concept for NH4+ removal from wastewater using porous geopolymer components fabricated via direct ink writing (DIW) AM approach. A metakaolin-based ink was employed for the fabrication of a log-pile structure with 45\ub0 rotation between layers, producing continuous yet tortuous macropores which are responsible for the high permeability of the sorbents. The ink consolidates in an amorphous, mesoporous network, with the mesopores acting as preferential sites for ion exchange. The printed sorbents were characterized for their physicochemical and mechanical properties and the NH4+ removal capacity in continuous-flow column experiments by using a model effluent. The lattices present high permeability and high cation exchange capacity and maintained a high amount of active ions after four cycles, allowing to reuse them multiple times

    The Effect of Low-Dose Aspirin On Serum Placental Growth Factor Levels In a High-Risk PREDO Cohort

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    Objectives: Our first aim was to study the longitudinal changes of serum placental growth factor (PlGF) concentration between 12(+0) and 28(+0) weeks of gestation in the prospective PREDO cohort. Our second aim was to study the effect of low-dose acetylsalicylic acid (LDA; 100 mg/day), started before the 14th week of gestation, on PlGF concentration. Study design: Blood samples were collected at 12(+0)-14(+0), 18(+0)-20(+0) and 26(+0)-28(+0) weeks of gestation in 101 women without and 309 with clinical risk factors for pre-eclampsia. Risk-women were divided into two groups: to those who had medium risk for pre-eclampsia and to those who had high risk for pre-eclampsia. Finally there were seven groups according to risk, treatment (no prevention/placebo/LDA) and outcome measure pre-eclampsia. Longitudinal changes in the PlGF concentration between groups were compared. To investigate the effect of LDA on serum PlGF concentration, placebo (N = 62) and LDA (N = 61) groups were compared. A repeated measures ANOVA was used to analyze differences in PlGF levels between the groups. Results: The increase in serum PlGF concentration was higher in LDA than in placebo group (time x group effect, p = 0.046). The increase in serum PlGF concentration during pregnancy was lower in high-risk women who had placebo and developed pre-eclampsia and in medium-risk women who developed pre-eclampsia compared to the other women (time x group effect, p <0.001). There were no differences in PlGF change between low-risk women, medium-risk women who did not develop pre-eclampsia, high-risk women in the placebo group without pre-eclampsia and high-risk women in the LDA group with and without pre-eclampsia (p = 0.15). Conclusions: Our finding suggests an association between LDA started before 14 weeks of gestation and higher increase in serum PlGF concentration.Peer reviewe
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