Polyhedral oligomeric silsesquioxane (POSS) is added to poly(hydroxyurethane) (PHU) prepolymers to create hybrid PHUs (HPHUs) with enhanced mechanical and thermal properties. These hybrid materials ...were then further functionalized with 3‐Isocyanatopropyl(trimethoxy) silane (IPTMS) via the pendent hydroxyl bonds within the backbone of the polymers to obtain a final cured film comparable to conventional polyurethanes (PU), using less isocyanate‐functional material. The incorporation of POSS into PHU prepolymers to obtain HPHUs was supported by gel permeation chromatography, fourier tranform infrared spectroscopy (FTIR) and nuclear magnetic resonance analysis. Furthermore, the thermal degradation of the HPHUs was significantly improved with increasing POSS concentration compared to their PHU counterparts as the degradation temperatures at 50% weight loss increased from 263°C for the PHU to 341°C for the HPHU. Gel content tests in tetrahydrofuran (THF), water, and toluene were performed and gel contents of 87%–99% in THF were observed for the cured films. Water swelling, and contact angle tests confirmed that the POSS‐modified films exhibited hydrophobic behavior. Finally, mechanical properties of the cured films were investigated. The Young's modulus and tensile strength were improved with increasing POSS concentration (from 2.0 to 3.1 MPa and from 0.82 to 1.32 MPa, respectively) and elongations at break up to 41.6% were observed. When compared to a conventional PU sealant, the HPHU achieved a tensile strength that was two‐fold greater and a comparable elongation at break (increasing from 24.8% to as high as 41.6%).
Polyhedral oligomeric silsesquioxane (POSS) are added to poly(hydroxyurethane) prepolymers to create hybrid polymers with enhanced mechanical and thermal properties. These hybrid materials were then further functionalized with 3‐Isocyanatopropyl(trimethoxy) silane via the pendent hydroxyl bonds within the backbone of the polymers to obtain a final cured film comparable to conventional polyurethanes.
The two-stage vibration isolation and positioning platform (BSC-ISI) provides three orders of magnitude of isolation at all frequencies above 1Hz.
•The paper presents near a decade of research on the ...two-stage twelve-axis vibration isolation platforms developed for Advanced LIGO.•This system positions and isolates 1000kg of very sensitive equipment in all directions of translation and rotation.•The system provides more than three orders of magnitude of isolation over a very large bandwidth.•We show how results from the prototyping phases have been used for the production and commissioning of 15 units.•Isolation results show that the system brings the motion below 10−11m/Hz at 1Hz and 10−12 m/Hz at 10Hz.
This paper presents the results of the past seven years of experimental investigation and testing done on the two-stage twelve-axis vibration isolation platform for Advanced LIGO gravity waves observatories. This five-ton two-and-half-meter wide system supports more than a 1000kg of very sensitive equipment. It provides positioning capability and seismic isolation in all directions of translation and rotation. To meet the very stringent requirements of Advanced LIGO, the system must provide more than three orders of magnitude of isolation over a very large bandwidth. It must bring the motion below 10−11 m/Hz at 1Hz and 10−12 m/Hz at 10Hz. A prototype of this system has been built in 2006. It has been extensively tested and analyzed during the following two years. This paper shows how the experimental results obtained with the prototype were used to engineer the final design. It highlights how the engineering solutions implemented not only improved the isolation performance but also greatly simplified the assembly, testing, and commissioning process. During the past two years, five units have been constructed, tested, installed and commissioned at each of the two LIGO observatories. Five other units are being built for an upcoming third observatory. The test results presented show that the system meets the motion requirements, and reach the sensor noise in the control bandwidth.
Background
To improve antimicrobial use, incorporation of a pharmacist in antimicrobial stewardship initiatives in the emergency department has been recommended. Recognizing the potential value, a ...pharmacist-led antimicrobial stewardship (AMS) service which included review and follow up of microbiology results for patients discharged from the pediatric emergency department (PED) with suspected infections was implemented at our local institution.
Objective
The objective of this study was to evaluate the impact of pharmacists delivering this service compared to usual care.
Setting
Pediatric emergency department at the IWK Health Centre in Halifax, Canada.
Method
This study was completed as a retrospective chart review of pediatric patients discharged from the PED 6 months before and after implementation of the pharmacist-led AMS service. Data was extracted from electronic medical records. Data were reported descriptively and compared using a two-sided chi-square test and ordinal logistic regression.
Main outcome measures
The primary outcome measure was rate of return visits to the PED within 96 h of initial presentation.
Results
This study included 1070 patient encounters pre-implementation and 1040 patient encounters post-implementation. The rate of return visits to the PED within 96 h was 12.0% (129/1070) pre-implementation vs. 10.0% (100/1049) post-implementation (
p
= 0.07). The rate of return visits or hospitalization at 30 days was 22.1% (237/1070) pre-implementation compared to 19.9% (207/1040) in the post-implementation phase (
p
= 0.21). Inappropriate antimicrobial therapy was identified more often in the pre-implementation phase (7.0%, 68/975) vs. the post-implementation phase (5.0%, 46/952),
p
= 0.047. Time to notification within the first day after discharge occurred more frequently in the post-implementation phase (53.3%, 80/150) as compared to the pre-implementation phase (40.3%, 52/129,
p
= 0.0298).
Conclusion
Although this pharmacist-led AMS service did not significantly affect the rate of return visits or hospitalization, it may have led to more judicious use of antimicrobial agents and faster time to notification.
The 1959 Kilauea Iki eruption provides a unique opportunity to investigate the process of shallow magma mixing, its impact on the magmatic volatile budget and its role in triggering and driving ...episodes of Hawaiian fountaining. Melt inclusions hosted by olivine record a continuous decrease in H2O concentration through the 17 episodes of the eruption, while CO2 concentrations correlate with the degree of post-entrapment crystallization of olivine on the inclusion walls. Geochemical data, when combined with the magma budget and with contemporaneous eruption observations, show complex mixing between episodes involving hot, geochemically heterogeneous melts from depth, likely carrying exsolved vapor, and melts which had erupted at the surface, degassed and drained-back into the vent. The drained-back melts acted as a coolant, inducing rapid cooling of the more primitive melts and their olivines at shallow depths and inducing crystallization and vesiculation and triggering renewed fountaining. A consequence of the mixing is that the melts became vapor-undersaturated, so equilibration pressures cannot be inferred from them using saturation models. After the melt inclusions were trapped, continued growth of vapor bubbles, caused by enhanced post-entrapment crystallization, sequestered a large fraction of CO2 from the melt within the inclusions. This study, while cautioning against accepting melt inclusion CO2 concentrations "as measured" in mixed magmas, also illustrates that careful analysis and interpretation of post-entrapment modifications can turn this apparent challenge into a way to yield novel useful insights into the geochemical controls on eruption intensity.
A soil–plant–atmosphere model was used to estimate gross primary productivity (GPP) and evapotranspiration (ET) of a tropical savanna in Australia. This paper describes model modifications required ...to simulate the substantial C4 grass understory together with C3 trees. The model was further improved to include a seasonal distribution of leaf area and foliar nitrogen through 10 canopy layers. Model outputs were compared with a 5‐year eddy covariance dataset. Adding the C4 photosynthesis component improved the model efficiency and root‐mean‐squared error (RMSE) for total ecosystem GPP by better emulating annual peaks and troughs in GPP across wet and dry seasons. The C4 photosynthesis component had minimal impact on modelled values of ET. Outputs of GPP from the modified model agreed well with measured values, explaining between 79% and 90% of the variance and having a low RMSE (0.003–0.281 g C m−2 day−1). Approximately, 40% of total annual GPP was contributed by C4 grasses. Total (trees and grasses) wet season GPP was approximately 75–80% of total annual GPP. Light‐use efficiency (LUE) was largest for the wet season and smallest in the dry season and C4 LUE was larger than that of the trees. A sensitivity analysis of GPP revealed that daily GPP was most sensitive to changes in leaf area index (LAI) and foliar nitrogen (Nf) and relatively insensitive to changes in maximum carboxylation rate (Vcmax), maximum electron transport rate (Jmax) and minimum leaf water potential (ψmin). The modified model was also able to represent daily and seasonal patterns in ET, (explaining 68–81% of variance) with a low RMSE (0.038–0.19 mm day−1). Current values of Nf, LAI and other parameters appear to be colimiting for maximizing GPP. By manipulating LAI and soil moisture content inputs, we show that modelled GPP is limited by light interception rather than water availability at this site.
Skinner and Pavlov had innovative ways to measure both the times of their subject's responses, as well as the rate of their responses. Since then, different subfields within the study of animal ...behavior have prioritized either the rate or timing of responses, creating a divide in data and theory. Both timing and conditioning fields have proven fruitful, producing large bodies of empirical data and developing sophisticated models. Despite their individual successes, a unified view of simple behavior is still lacking. This may be caused, at least in part, by the differential emphasis on data collection and analysis techniques. The result is that these subfields produce models that fit their data well, but fail to translate to the other domain. This is startling given the fact that both subfields use nearly identical experimental procedures. To highlight similarities within the subfields, and provide empirical data in support of this integration, 18 Sprague-Dawley rats were trained on trace, delay, and backward conditioning procedures. Using these empirical data we discuss how traditional summary measures used by these subfields can be limiting, and suggest methods that may aid in the integration of these subfields toward common goals.
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