Vortex-induced vibration of catenary riser: reduced-order modeling and lock-in analysis using wake oscillator

A new reduced-order model capable of analyzing the vortex-induced vibration of catenary riser in the ocean current has been developed. This semi analytical-numerical approach is versatile and allows for a significant reduction in computational effort for the analysis of fluid-riser interactions. The incoming current flow is assumed to be steady, uniform, unidirectional and perpendicular to the riser plane of initial equilibrium curvatures

Placenta Percreta; A Report On Surviving Death From The Bleeding Disaster!

A 34 year old G6P5 diagnosed with placenta previa percreta (fig 1) in her 2nd trimester was reviewed by a multidisciplinary team. Baby delivery was planned at 34 weeks gestation by cesarean hysterectomy(CH) immediately preceded by bilateral ureteral stents for anticipated surgical complexity. Patient received combined spinal and epidural (not activated) for the ureteric stenting with an aim to use the epidural for post-operative analgesia followed by general anesthesia and establishment of invasive lines and monitoring prior to start of CH. Soon after baby delivery, patient became hypotensive from severe hemorrhage. Massive transfusion protocol was instituted. After completion of hysterectomy, patient continued to bleed from multiple intraabdominal sites. While surgical hemostasis remained a challenge, patient developed PEA arrest. CPR was started with return of spontaneous circulation (ROSC) after chest compression for 2 minutes and 1mg of epinephrine. Following this, abdomen was packed with a decision to close secondarily after interventional radiology (IR) assisted intervention if necessary and hemodynamic stabilization. Intraoperatively, patient received a total of 29pRBCs, 22FFP, 4platelet & 3Cryo units with 21 L of crystalloids, 3.25 L of 5% albumin and 1.8L of cell saver with an estimated blood loss of 25L. Tranexamic acid and prothrombin complex concentrate was given. Thromboelastogram (TEG) and lab based coagulation profile was used intraoperatively to guide blood component transfusion. Serial blood gas analyses guided volume and electrolyte correction. In the ICU patient improved with no neurological insult or DIC. On postop day 1 IR found no active extravasations and surgical abdominal closure was performed. Epidural catheter was used for postoperative pain control and was removed on day 4. Patient was discharged on postop day 10.https://scholarlycommons.henryford.com/merf2020caserpt/1124/thumbnail.jp

Placenta Percreta: A Report On Surviving Death From The Bleeding Disaster!

https://scholarlycommons.henryford.com/merf2020caserpt/1001/thumbnail.jp

Cosmological Simulations of the Preheating Scenario for Galaxy Cluster Formation: Comparison to Analytic Models and Observations

We perform a set of non--radiative cosmological simulations of a preheated intracluster medium in which the entropy of the gas was uniformly boosted at high redshift. The results of these simulations are used first to test the current analytic techniques of preheating via entropy input in the smooth accretion limit. When the unmodified profile is taken directly from simulations, we find that this model is in excellent agreement with the results of our simulations. This suggests that preheated efficiently smoothes the accreted gas, and therefore a shift in the unmodified profile is a good approximation even with a realistic accretion history. When we examine the simulation results in detail, we do not find strong evidence for entropy amplification, at least for the high-redshift preheating model adopted here. In the second section of the paper, we compare the results of the preheating simulations to recent observations. We show -- in agreement with previous work -- that for a reasonable amount of preheating, a satisfactory match can be found to the mass-temperature and luminosity-temperature relations. However -- as noted by previous authors -- we find that the entropy profiles of the simulated groups are much too flat compared to observations. In particular, while rich clusters converge on the adiabatic self--similar scaling at large radius, no single value of the entropy input during preheating can simultaneously reproduce both the core and outer entropy levels. As a result, we confirm that the simple preheating scenario for galaxy cluster formation, in which entropy is injected universally at high redshift, is inconsistent with observations.Comment: 11 pages, 13 figures, accepted for publication in Ap

Predicting the dynamics and heterogeneity of genomic DNA content within bacterial populations across variable growth regimes

For many applications in microbial synthetic biology, optimizing a desired function requires careful tuning of the degree to which various genes are expressed. One challenge for predicting such effects or interpreting typical characterization experiments is that in bacteria such as E. coli, genome copy number varies widely across different phases and rates of growth, which also impacts how and when genes are expressed from different loci. While such phenomena are relatively well-understood at a mechanistic level, our quantitative understanding of such processes is essentially limited to ideal exponential growth. In contrast, common experimental phenomena such as growth on heterogeneous media, metabolic adaptation, and oxygen restriction all cause substantial deviations from ideal exponential growth, particularly as cultures approach the higher densities at which industrial biomanufacturing and even routine screening experiments are conducted. To meet the need for predicting and explaining how gene dosage impacts cellular functions outside of exponential growth, we here report a novel modeling strategy that leverages agent-based simulation and high performance computing to robustly predict the dynamics and heterogeneity of genomic DNA content within bacterial populations across variable growth regimes. We show that by feeding routine experimental data, such as optical density time series, into our heterogeneous multiphasic growth simulator, we can predict genomic DNA distributions over a range of nonexponential growth conditions. This modeling strategy provides an important advance in the ability of synthetic biologists to evaluate the role of genomic DNA content and heterogeneity in affecting the performance of existing or engineered microbial functions

The physical scale of the far-infrared emission in the most luminous submillimetre galaxies II: evidence for merger-driven star formation

We present high-resolution 345 GHz interferometric observations of two extreme luminous (L_{IR}>10^{13} L_sun), submillimetre-selected galaxies (SMGs) in the COSMOS field with the Submillimeter Array (SMA). Both targets were previously detected as unresolved point-sources by the SMA in its compact configuration, also at 345 GHz. These new data, which provide a factor of ~3 improvement in resolution, allow us to measure the physical scale of the far-infrared in the submillimetre directly. The visibility functions of both targets show significant evidence for structure on 0.5-1 arcsec scales, which at z=1.5 translates into a physical scale of 5-8 kpc. Our results are consistent with the angular and physical scales of two comparably luminous objects with high-resolution SMA followup, as well as radio continuum and CO sizes. These relatively compact sizes (<5-10 kpc) argue strongly for merger-driven starbursts, rather than extended gas-rich disks, as the preferred channel for forming SMGs. For the most luminous objects, the derived sizes may also have important physical consequences; under a series of simplifying assumptions, we find that these two objects in particular are forming stars close to or at the Eddington limit for a starburst.Comment: 9 pages, 3 Figures, submitted to MNRA

AzTEC Millimetre Survey of the COSMOS Field - II. Source Count Overdensity and Correlations with Large-Scale Structure

We report an over-density of bright sub-millimetre galaxies (SMGs) in the 0.15 sq. deg. AzTEC/COSMOS survey and a spatial correlation between the SMGs and the optical-IR galaxy density at z <~ 1.1. This portion of the COSMOS field shows a ~ 3-sigma over-density of robust SMG detections when compared to a background, or "blankfield", population model that is consistent with SMG surveys of fields with no extragalactic bias. The SMG over-density is most significant in the number of very bright detections (14 sources with measured fluxes S(1.1mm) > 6 mJy), which is entirely incompatible with sample variance within our adopted blank-field number densities and infers an over-density significance of >> 4. We find that the over-density and spatial correlation to optical-IR galaxy density are most consistent with lensing of a background SMG population by foreground mass structures along the line of sight, rather than physical association of the SMGs with the z <~ 1.1 galaxies/clusters. The SMG positions are only weakly correlated with weak-lensing maps, suggesting that the dominant sources of correlation are individual galaxies and the more tenuous structures in the region and not the massive and compact clusters. These results highlight the important roles cosmic variance and large-scale structure can play in the study of SMGs.Comment: 12 pages, 11 figures, 2 tables, accepted for publication in MNRA

Precise Identifications of Submillimeter Galaxies: Measuring the History of Massive Star-Forming Galaxies to z>5

We carried out extremely sensitive Submillimeter Array (SMA) 340 GHz (860 micron) continuum imaging of a complete sample of SCUBA 850 micron sources (>4 sigma) with fluxes >3 mJy in the GOODS-N. Using these data and new SCUBA-2 data, we do not detect 4 of the 16 SCUBA sources, and we rule out the original SCUBA fluxes at the 4 sigma level. Three more resolve into multiple fainter SMA galaxies, suggesting that our understanding of the most luminous high-redshift dusty galaxies may not be as reliable as we thought. 10 of the 16 independent SMA sources have spectroscopic redshifts (optical/infrared or CO) to z=5.18. Using a new, ultradeep 20 cm image obtained with the Karl G. Jansky Very Large Array (rms of 2.5 microJy), we find that all 16 of the SMA sources are detected at >5 sigma. Using Herschel far-infrared (FIR) data, we show that the five isolated SMA sources with Herschel detections are well described by an Arp 220 spectral energy distribution template in the FIR. They also closely obey the local FIR-radio correlation, a result that does not suffer from a radio bias. We compute the contribution from the 16 SMA sources to the universal star formation rate (SFR) per comoving volume. With individual SFRs in the range 700-5000 solar masses per year, they contribute ~30% of the extinction-corrected ultraviolet-selected SFR density from z=1 to at least z=5. Star formation histories determined from extinction-corrected ultraviolet populations and from submillimeter galaxy populations only partially overlap, due to the extreme ultraviolet faintness of some submillimeter galaxies.Comment: 26 pages, minor changes to match published versio

Evaluation of the protection against norovirus afforded by E. coli monitoring of shellfish production areas under EU regulations

EC Regulation 854/2004 requires the classification of bivalve mollusc harvesting areas according to the faecal pollution status of sites. It has been reported that determination of Escherichia coli in bivalve shellfish is a poor predictor of norovirus (NoV) contamination in individual samples. We explore the correlation of shellfish E. coli data with norovirus presence using data from studies across 88 UK sites (1,184 paired samples). We investigate whether current E. coli legislative standards could be refined to reduce NoV infection risk. A significant relationship between E. coli and NoV was found in the winter months (October to February) using data from sites with at least 10 data pairs (51 sites). We found that the ratio of arithmetic means (log10 E. coli to log10 NoV) at these sites ranged from 0.6 to 1.4. The lower ratios (towards 0.6) might typically indicate situations where the contribution from UV disinfected sewage discharges was more significant. Conversely, higher ratios (towards 1.4) might indicate a prevalence of animal sources of pollution; however, this relationship did not always hold true and so further work is required to fully elucidate the factors of relevance. Reducing the current class B maximum (allowed in 10% of samples) from 46,000 E. coli per 100 g (corresponding NoV value of 75750±103) to 18,000 E. coli per 100 g (corresponding NoV value of 29365±69) reduces maximum levels of NoV by a factor of 2.6 to 1; reducing the upper class B limit to 100% compliance with 4,600 E. coli per 100 g (corresponding NoV value of 7403±39) reduces maximum levels of NoV by a factor of 10.2 to 1. We found using the UK filtered winter dataset that a maximum of 200 NoV corresponded to a maximum of 128±7 E. coli per 100 g. A maximum of 1,000 NoV corresponded to a maximum of 631±14 E. coli per 100 g