Weak Gravitational Lensing and Cluster Mass Estimates

Hierarchical theories of structure formation predict that clusters of galaxies should be embedded in a web like structure, with filaments emanating from them to large distances. The amount of mass contained within such filaments near a cluster can be comparable to the collapsed mass of the cluster itself. Diffuse infalling material also contains a large amount of mass. Both these components can contribute to the cluster weak lensing signal. This ``projection bias'' is maximized if a filament lies close to the line-of-sight to a cluster. Using large--scale numerical simulations of structure formation in a cosmological constant dominated cold dark matter model, we show that the projected mass typically exceeds the actual mass by several tens of percent. This effect is significant for attempts to estimate cluster masses through weak lensing observations, and will affect weak lensing surveys aimed at constructing the cluster mass function.Comment: 4 pages, 3 figures. LaTeX2e, uses emulateapj.sty and onecolfloat.sty. To be submitted to the Astrophysical Journal Letter

Femoral vs sciatic nerve block to provide analgesia after medial open wedge high tibial osteotomy in the setting of multimodal analgesia: A randomized, controlled, single-blinded trial.

Medial open wedge high tibial osteotomy (MOW HTO) is associated with moderate to severe postoperative pain. The proximal part of the tibia is innervated by branches from the femoral nerve anteriorly and the sciatic nerve posteriorly. There is a paucity of information regarding the optimal peripheral nerve block for postoperative analgesia with minimal impact on motor function. This study tested the hypothesis that a femoral nerve block provides superior analgesia to a sciatic nerve block after MOW HTO in the setting of multimodal analgesia. Randomized controlled single-blind trial. Operating room, postoperative recovery area and ward, up to 6 postoperative months. Fifty patients undergoing MOW HTO. Interventions were femoral or sciatic nerve block under ultrasound guidance. For each intervention, a total of 100 mg of ropivacaine was injected. Postoperative pain treatment followed a pre-defined protocol with intravenous patient-controlled analgesia of morphine, paracetamol, and ibuprofen. The primary outcome was intravenous morphine consumption at 24 h postoperatively. Secondary outcomes included rest and dynamic pain scores (on a numeric rating scale out of 10) at 2, 24 and 48 h postoperatively. Functional outcomes included the Short Form-12, Knee injury and Osteoarthritis Outcome Score, and International Knee Documentation Committee (IKDC) scores measured at 6 months postoperatively. Mean [95% confidence interval] i.v. morphine consumption at 24 postoperative hours were 24 mg [15 mg,33 mg] in the femoral nerve block group and 24 mg [16 mg,32 mg] in the sciatic nerve block group (p = 0.98). There were no significant differences in the secondary outcomes between groups. This trial failed to demonstrate that a femoral nerve block provides superior analgesia to a sciatic nerve block after MOW HTO under general anesthesia in the setting of multimodal analgesia. There was no significant difference in quality of life and functional outcomes at 6 months postoperatively between groups. Trial registry number:Clinicaltrials.com - NCT05728294; Kofam.ch - SNCTP000003048 | BASEC2018-01774

Flashboiling-induced targeting changes in gasoline direct injection sprays

By definition, flashboiling is referred to as superheated injections. The sudden occurrence of boiling inside the fuel can change the spray structure dramatically. Up to 99% of all injection processes during the New European Driving Cycle and 95% during ‘Real Driving Emissions’ tests are, with respect to mid-range cars, in a state of thermodynamic non-equilibrium below the specific vapor pressure of gasoline. Considering this fact, the scientific question is not the appearance of flashboiling during the operation of stoichiometric homogeneous charge direct injection gasoline engines but the intensity of occurring spray processes and their influence on nominal spray designs. As a consequence of induced targeting changes, the positive influence of flashboiling on the droplet size distribution and the penetration depth can be counteracted. As main driving factors for targeting changes, jet-to-jet interactions can be identified. By applying appropriate nozzle design features, the potential of flashboiling can be exploited and the targeting changes of the nominal spray designs, considered negatively, are avoided mostly. This work focuses on flashboiling-induced targeting changes, the so-called phenomenon of “spray collapse”: its root cause, development and avoidance

Remotely Sensed Land Surface Temperature Can Be Used to Estimate Ecosystem Respiration in Intact and Disturbed Northern Peatlands

https://doi.org/10.1029/2021JG006411Remotely sensed land surface temperature (LST) enables global modeling and monitoring of CO2 fluxes from peatlands. We aimed to provide the first overview of the potential for using LST to monitor ecosystem respiration (R-eco) in disturbed (drained and extracted) peatlands. We used chamber-measured data (2017-2020) from five disturbed and two intact northern peatlands and LST data from Landsat 7, 8, and MODIS missions. First, we studied the strength of the relationships between fluxes and their in situ drivers (i.e., thermal and moisture conditions). Second, we examined the association between LST and in situ temperatures. Third, we compared chamber-measured R-eco with the modeled R-eco driven by in situ measured water table depth and (a) in situ measured surface temperature and (b) remotely sensed MODIS LST data. In situ temperatures were a stronger driver of CO2 fluxes in disturbed sites (repeated measures correlation rmR = 0.8-0.9) than in intact ones (rmR = 0.5-0.8). LST had a higher association with in situ measured temperatures in disturbed sites (mean rmR = 0.79 for MODIS) and weaker in the intact (hummocks and hollows) peatlands (mean rmR = 0.38 for Landsat and 0.48 for MODIS). R-eco models driven by MODIS LST and in situ surface temperature yielded similar accuracy: R-2 was 0.27, 0.66, and 0.67 and 0.29, 0.70, and 0.66 for intact and for drained and extracted sites, respectively. Overall, these findings suggest the applicability of LST as a proxy of the thermal regime in R-eco models, particularly for disturbed peatlands.Peer reviewe

Täiskasvanute sõeluuringud Eestis 2023. aasta seisuga

Eesti Arst 2023; 102(8):418–42

The Effect of the Cosmic Web on Cluster Weak Lensing Mass Estimates

In modern hierarchical theories of structure formation, rich clusters of galaxies form at the vertices of a weblike distribution of matter, with filaments emanating from them to large distances and with smaller objects forming and draining in along these filaments. The amount of mass contained in structure near the cluster can be comparable to the collapsed mass of the cluster itself. As the lensing kernel is quite broad along the line of sight around cluster lenses with typical redshifts near z=0.5, structures many Mpc away from the cluster are essentially at the same location as the cluster itself, when considering their effect on the cluster's weak lensing signal. We use large-scale numerical simulations of structure formation in a Lambda-dominated cold dark matter model to quantify the effect that large-scale structure near clusters has upon the cluster masses deduced from weak lensing analysis. A correction for the scatter in possible observed lensing masses should be included when interpreting mass functions from weak lensing surveys.Comment: 14 pages, 11 figures. LaTeX2e, uses emulateapj.sty and onecolfloat.st

High Speed X-Ray Imaging for Nozzle Exit Velocity and Density Distribution Measurements of GDI Nozzles

[EN] Investigation of the primary breakup region of gasoline sprays is important for future nozzle development. It improves the principal understanding of inner nozzle flow and spray breakup. It also allows validating and developing CFD models. Due to the high optical density common measurement techniques like Phase Doppler Anemometry reach their limit in optical dense sprays as in the primary breakup region. High Speed X-Ray Imaging is capable to measure 2D velocity distributions directly at the spray hole exit. For generating the intense X-Ray beam the synchrotron Advanced Photon Source at Argonne National Laboratory is used. Passing through the spray the X-Ray beam is changed by two different physical principles: absorption and phase contrast. Absorption can be applied to measure the density of the spray. Phase contrast is used to visualize the borders of droplets and ligaments with high contrast. The accelerated electron bunches inside the synchrotron have a constant period length to each other. This leads to an accurate pulsed X-Ray beam (periodicity: 68 ns). The use of multi exposure with very short X-Ray pulses (17 ns) shows the traveled distance of the spray droplets and ligaments. The spray speed (150-250 m/s) is calculated by dividing these distances with the time gap between two X-Ray pulses. The X-Ray measured density distributions and velocity distributions are combined to calculate the spray force rate. The so gained force rate is validated with a spray force measurement performed at the Spray Momentum Test Bench (SMTB) at Continental Automotive GmbH. The study is focusing on the measurement setup of High Speed X-Ray Imaging at Argonne National Laboratory and the evaluation algorithms.This work is supported by the US Department of Energy, Basic Energy Sciences, Office of Science, under Contract No. 852W5.Distler, R.; Hamann, C.; Krämer, M.; Kull, E.; Wensing, M.; Li, Z.; Gao, Y.... (2017). High Speed X-Ray Imaging for Nozzle Exit Velocity and Density Distribution Measurements of GDI Nozzles. En Ilass Europe. 28th european conference on Liquid Atomization and Spray Systems. Editorial Universitat Politècnica de València. 669-676. https://doi.org/10.4995/ILASS2017.2017.4598OCS66967

Prosomes exist in plant cells too

A 19S particle was purified from tobacco (Nicotiana rustica) leaf cells. Its density was determined as 1296 g/cm3 in Cs2SO4-DMSO gradients, indicating the presence of RNA and protein. Polyacrylamide gel electrophoresis (PAGE) revealed eight distinct proteins in the range of 20-30 kD and RNA in the range of 70-80 nucleotides. Electron microscopic examination showed the same raspberry-shaped structure with a central depression as described for prosomes. We conclude that tobacco 19S particles represent small cytoplasmic complexes, possessing biochemical and structural characteristics similar to the hitherto known prosomes of animal cells