Seismic attenuation due to wave-induced flow Pride, S. R.; Berryman, J. G.; Harris, J. M.
Journal of Geophysical Research - Solid Earth,
January 2004, Volume:
109, Issue:
B1
Journal Article
Peer reviewed
Open access
Three P wave attenuation models for sedimentary rocks are given a unified theoretical treatment. Two of the models concern wave‐induced flow due to heterogeneity in the elastic moduli at “mesoscopic” ...scales (scales greater than grain sizes but smaller than wavelengths). In the first model, the heterogeneity is due to lithological variations (e.g., mixtures of sands and clays) with a single fluid saturating all the pores. In the second model, a single uniform lithology is saturated in mesoscopic “patches” by two immiscible fluids (e.g., air and water). In the third model, the heterogeneity is at “microscopic” grain scales (broken grain contacts and/or microcracks in the grains), and the associated fluid response corresponds to “squirt flow.” The model of squirt flow derived here reduces to proper limits as any of the fluid bulk modulus, crack porosity, and/or frequency is reduced to zero. It is shown that squirt flow is incapable of explaining the measured level of loss (10−2 < Q−1 < 10−1) within the seismic band of frequencies (1–104 Hz); however, either of the two mesoscopic scale models easily produces enough attenuation to explain the field data.
Efficacious euthanasia by applying manual cervical dislocation can be difficult on large and mature poultry. The challenge with using manual cervical dislocation is that the strength required to hold ...heavy poultry and swiftly apply cervical dislocation can be physically impossible for most people. Therefore, alternative methods of euthanasia are needed for mature and large poultry. Mechanical cervical dislocation using the Koechner Euthanizing Device (KED), captive bolt using the Turkey Euthanasia Device (TED), carbon dioxide (CO2), and electrical euthanasia were evaluated for use on 65-wk-old broiler breeders at flock termination. Following application of each method, physiological reflexes including the eye nictitating membrane reflex, mouth gaping, and body movement, broken skin, blood loss, kill success, time to cessation of heartbeat, and blood plasma corticosterone levels were assessed. Birds euthanized using the KED had longer response durations for eye nictitating membrane (91 s) and reflexive mouth gaping (161 s) compared to TED, CO2, and electrical euthanasia (0–7 s). Body movement durations were also longer for KED (214 s) and TED (209 s) than for CO2 and electrical euthanasia (0–8 s). The highest percentages of broken skin (93%) and blood loss (96%) were observed for TED, followed by KED (71%, 68%), then CO2 (0%, 6%) and electrical euthanasia (0%, 3%). No significant differences (P = 0.1781) were observed for kill success rates with 98% for KED, 100% for TED, 97% for CO2, and 100% for electrical euthanasia at 4-min. Time to heartbeat cessation did not differ between KED (659 s), TED (427 s), or CO2 (583 s) euthanasia methods. No heartbeat was detected following electrical euthanasia. Blood plasma corticosterone levels did not differ between preeuthanasia or posteuthanasia from any of the methods applied. Based on these results each euthanasia method is acceptable for use with broiler breeders.
The use of Fourier-transform mid-infrared (FTIR) spectroscopy is of interest to the dairy industry worldwide for predicting milk composition and other novel traits that are difficult or expensive to ...measure directly. Although there are many valuable applications for FTIR spectra, noise from differences in spectral responses between instruments is problematic because it reduces prediction accuracy if ignored. The purpose of this study was to develop strategies to reduce the impact of noise and to compare methods for standardizing FTIR spectra in order to reduce between-instrument variability in multiple-instrument networks. Noise levels in bands of the infrared spectrum caused by the water content of milk were characterized, and a method for identifying and removing outliers was developed. Two standardization methods were assessed and compared: piecewise direct standardization (PDS), which related spectra on a primary instrument to spectra on 5 other (secondary) instruments using identical milk-based reference samples (n = 918) analyzed across the 6 instruments; and retroactive percentile standardization (RPS), whereby percentiles of observed spectra from routine milk test samples (n = 2,044,094) were used to map and exploit primary- and secondary-instrument relationships. Different applications of each method were studied to determine the optimal way to implement each method across time. Industry-standard predictions of milk components from 2,044,094 spectra records were regressed against predictions from spectra before and after standardization using PDS or RPS. The PDS approach resulted in an overall decrease in root mean square error between industry-standard predictions and predictions from spectra from 0.190 to 0.071 g/100 mL for fat, from 0.129 to 0.055 g/100 mL for protein, and from 0.143 to 0.088 g/100 mL for lactose. Reductions in prediction error for RPS were similar but less consistent than those for PDS across time, but similar reductions were achieved when PDS coefficients were updated monthly and separate primary instruments were assigned for the North and South Islands of New Zealand. We demonstrated that the PDS approach is the most consistent method to reduce prediction errors across time. We also showed that the RPS approach is sensitive to shifts in milk composition but can be used to reduce prediction errors, provided that secondary-instrument spectra are standardized to a primary instrument with samples of broadly equivalent milk composition. Appropriate implementation of either of these approaches will improve the quality of predictions based on FTIR spectra for various downstream applications.
Background
The aim of this systematic review and meta‐analysis was to compare clinical outcomes following single‐incision laparoscopic appendicectomy (SILA) and conventional multiport laparoscopic ...appendicectomy (CLA) for the treatment of acute appendicitis.
Methods
An electronic search of MEDLINE, Embase, Web of Science and Cochrane Library databases was performed. Publications were included if they were clinical trials randomizing patients with appendicitis to SILA or CLA. Outcome measures evaluated included operating time, length of hospital stay, total postoperative complications, and, specifically, wound infection, intra‐abdominal collection and ileus. Weighted mean difference was calculated for the effect size of SILA on continuous variables, and pooled odds ratios were calculated for discrete variables.
Results
The literature search identified seven randomized clinical trials that met the inclusion criteria for meta‐analysis. In total, 1108 appendicectomies were included, 555 SILA and 553 CLA procedures. There were no significant differences between the groups in the incidence of total postoperative complications, wound infection, intra‐abdominal collection, ileus or length of hospital stay. However, SILA was associated with a significantly longer operating time compared with CLA (weighted mean difference 6·96 (95 per cent confidence interval 3·79 to 10·12) min; P < 0·001). Insertion of an additional port was required in 7·6 per cent of patients undergoing SILA.
Conclusion
SILA is a safe procedure for the treatment of acute appendicitis, with comparable clinical outcome to CLA when undertaken by experienced laparoscopic surgeons.
Single‐incision laparoscopic appendicectomy takes significantly longer
Hypertension (HTN) is a significant risk factor for cardiovascular morbidity and mortality. Metabolic abnormalities, including adverse cholesterol and triglycerides (TG) profiles, are frequent ...comorbid findings with HTN and contribute to cardiovascular disease. Diuretics, which are used to treat HTN and heart failure, have been associated with worsening of fasting lipid concentrations. Genome-wide meta-analyses with 39,710 European-ancestry (EA) individuals and 9925 African-ancestry (AA) individuals were performed to identify genetic variants that modify the effect of loop or thiazide diuretic use on blood lipid concentrations. Both longitudinal and cross sectional data were used to compute cohort-specific interaction results, which were then combined through meta-analysis in each ancestry. These ancestry-specific results were further combined through trans-ancestry meta-analysis. Analysis of EA data identified two genome-wide significant (p < 5 × 10
) loci with single nucleotide variant (SNV)-loop diuretic interaction on TG concentrations (including COL11A1). Analysis of AA data identified one genome-wide significant locus adjacent to BMP2 with SNV-loop diuretic interaction on TG concentrations. Trans-ancestry analysis strengthened evidence of association for SNV-loop diuretic interaction at two loci (KIAA1217 and BAALC). There were few significant SNV-thiazide diuretic interaction associations on TG concentrations and for either diuretic on cholesterol concentrations. Several promising loci were identified that may implicate biologic pathways that contribute to adverse metabolic side effects from diuretic therapy.
Additive Manufacturing is transforming how researchers and industrialists look to design and manufacture chemical devices to meet their specific needs. In this work, we report the first example of a ...flow reactor formed via the solid-state metal sheet lamination technique, Ultrasonic Additive Manufacturing (UAM), with directly integrated catalytic sections and sensing elements. The UAM technology not only overcomes many of the current limitations associated with the additive manufacturing of chemical reactionware but it also significantly increases the functionality of such devices. A range of biologically important 1, 4-disubstituted 1, 2, 3-triazole compounds were successfully synthesised and optimised in-flow through a Cu mediated Huisgen 1, 3-dipolar cycloaddition using the UAM chemical device. By exploiting the unique properties of UAM and continuous flow processing, the device was able to catalyse the proceeding reactions whilst also providing real-time feedback for reaction monitoring and optimisation.
In recent years, rapid progress in the use of the internet has resulted in huge losses in many organizations due to lax security. As a result, information security awareness is becoming an important ...issue to anyone using the Internet. To reduce losses, organizations have made information security awareness a top priority. The three main barriers to information security awareness are: (1) general security awareness, (2) employees’ computer skills, and (3) organizational budgets. Online learning appears a feasible alternative to providing information security awareness and countering these three barriers. Research has identified three levels of security awareness: perception, comprehension and projection. This paper reports on a laboratory experiment that investigates the impacts of hypermedia, multimedia and hypertext to increase information security awareness among the three awareness levels in an online training environment. The results indicate that: (1) learners who have the better understanding at the perception and comprehension levels can improve understanding at the projection level; (2) learners with text material perform better at the perception level; and (3) learners with multimedia material perform better at the comprehension level and projection level. The results could be used by educators and training designers to create meaningful information security awareness materials.
The gold standard for hand hygiene (HH) while wearing gloves requires removing gloves, performing HH, and donning new gloves between WHO moments. The novel strategy of applying alcohol-based hand rub ...(ABHR) directly to gloved hands might be effective and efficient.
A mixed-method, multicenter, 3-arm, randomized trial.
Adult and pediatric medical-surgical, intermediate, and intensive care units at 4 hospitals.
Healthcare personnel (HCP).
HCP were randomized to 3 groups: ABHR applied directly to gloved hands, the current standard, or usual care.
Gloved hands were sampled via direct imprint. Gold-standard and usual-care arms were compared with the ABHR intervention.
Bacteria were identified on gloved hands after 432 (67.4%) of 641 observations in the gold-standard arm versus 548 (82.8%) of 662 observations in the intervention arm (
< .01). HH required a mean of 14 seconds in the intervention and a mean of 28.7 seconds in the gold-standard arm (
< .01). Bacteria were identified on gloved hands after 133 (98.5%) of 135 observations in the usual-care arm versus 173 (76.6%) of 226 observations in the intervention arm (
< .01). Of 331 gloves tested 6 (1.8%) were found to have microperforations; all were identified in the intervention arm 6 (2.9%) of 205.
Compared with usual care, contamination of gloved hands was significantly reduced by applying ABHR directly to gloved hands but statistically higher than the gold standard. Given time savings and microbiological benefit over usual care and lack of feasibility of adhering to the gold standard, the Centers for Disease Control and Prevention and the World Health Organization should consider advising HCP to decontaminate gloved hands with ABHR when HH moments arise during single-patient encounters.
NCT03445676.
The Hedgehog (Hh) pathway is well known for its involvement in angiogenesis and vasculogenesis during ontogeny. The ligand, Sonic Hh (SHH), has an important role in vascular formation during ...development. However, SHH expression is upregulated on tumor cells and can impact the tumor microenvironment. We have investigated the effects of autocrine as well as paracrine Hh signaling on tumor cells as well as on endothelial cells, respectively. Upon constitutive expression of SHH, breast cancer cells showed aggressive behavior and rapid xenograft growth characterized by highly angiogenic tumors that were spontaneously metastatic. In these cells, SHH caused activation of the Hh transcription factor, GLI1, leading to upregulated expression of the potent pro-angiogenic secreted molecule, CYR61 (cysteine-rich angiogenic inducer 61). Silencing of CYR61 from these SHH-expressing Hh activated cells blunted the malignant behavior of the tumor cells and resulted in reduced tumor vasculature and limited hematogenous metastases. Thus, CYR61 is a critical downstream contributor to the Hh influenced pro-angiogenic tumor microenvironment. We also observed concomitant upregulation of SHH and CYR61 transcripts in tumors from patients with advanced breast cancer, further ratifying the clinical relevance of our findings. In summary, we have defined a novel, VEGF-independent, clinically relevant, pro-angiogenic factor, CYR61, that is a transcriptional target of Hh-GLI signaling.
Sintered NdFeB-based scrap magnets were recovered and processed using the HD and HDDR routes. The effects of varying the HDDR processing temperature were investigated (over the range 835–930°C). The ...disproportion was carried out with a pressure ramp to a maximum of 1000mbar hydrogen pressure with a 1h hold time at each step and the optimum recombination conditions were set at 100mbar with a 20min hold time. Anisotropic NdFeB powder was produced in all cases with the best magnetic properties achieved at a processing temperature of 880°C, producing powder with a remanence of 1.10(±0.02)T and an intrinsic coercivity of 800 (±16)kAm−1 and giving a (BH)max of 129(±2.5)kJm−3.
► Production of anisotropic permanent magnet powder from scrap NdFeB magnets by HDDR. ► Reaction pressure increases with increasing processing temperature. ► Best magnetic properties achieved by processing at 880°C.
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