20 research outputs found
Sensitivity of storm surge predictions to atmospheric forcing during Hurricane Isaac
Storm surge and overland flooding can be predicted with computational models at high levels of resolution. To improve efficiency in forecasting applications, surge models often use atmospheric forcing from parametric vortex models, which represent the surface pressures and wind fields with a few storm parameters. The future of storm surge prediction could involve real-time coupling of surge and full-physics atmospheric models; thus, their accuracies must be understood in a real hurricane scenario. The authors compare predictions from a parametric vortex model (using forecast tracks from the National Hurricane Center) and a full-physics coupled atmosphere-wave-ocean model during Hurricane Isaac (2012). The predictions are then applied within a tightly coupled, wave and surge modeling system describing the northern Gulf of Mexico and the floodplains of southwest Louisiana. It is shown that, in a hindcast scenario, a parametric vortex model can outperform a data-assimilated wind product, and given reasonable forecast advisories, a parametric vortex model gives reasonable surge forecasts. However, forecasts using a full-physics coupled model outperformed the forecast advisories and improved surge forecasts. Both approaches are valuable for forecasting the coastal impacts associated with tropical cyclones
PROFIT: a new alternative for emission-line PROfile FITting
I briefly describe a simple routine for emission-line profiles fitting by
Gaussian curves or Gauss-Hermite series. The PROFIT (line-PROfile FITting)
routine represent a new alternative for use in fits data cubes, as those from
Integral Field Spectroscopy or Fabry-Perot Interferometry, and may be useful to
better study the emission-line flux distributions and gas kinematics in
distinct astrophysical objects, such as the central regions of galaxies and
star forming regions. The PROFIT routine is written in IDL language and is
available at http://www.ufsm.br/rogemar/software.html.
The PROFIT routine was used to fit the [Fe II]1.257um emission-line profiles
for about 1800 spectra of the inner 350 pc of the Seyfert galaxy Mrk1066
obtained with Gemini NIFS and shows that the line profiles are better
reproduced by Gauss-Hermite series than by the commonly used Gaussian curves.
The two-dimensional map of the h_3 Gauss-Hermite moment shows its highest
absolute values in regions close to the edge of the radio structure. These high
values may be originated in an biconical outflowing gas associated with the
radio jet - previously observed in the optical [O III] emission. The analysis
of this kinematic component indicates that the radio jet leaves the center of
the galaxy with the north-west side slightly oriented towards us and the
south-east side away from us, being partially hidden by the disc of the galaxy.Comment: Accepted for publication Astrophysics & Space Science - 7 pges; 4
Fig
Large-scale collective motion of RFGC galaxies in curved space-time
We consider large-scale collective motion of flat edge-on spiral galaxies
from the Revised Flat Galaxy Catalogue (RFGC) taking into account the curvature
of space-time in the Local Universe at the scale 100 Mpc/h. We analyse how the
relativistic model of collective motion should be modified to provide the best
possible values of parameters, the effects that impact these parameters and
ways to mitigate them. Evolution of galactic diameters, selection effects, and
difference between isophotal and angular diameter distances are inadequate to
explain this impact. At the same time, measurement error in HI line widths and
angular diameters can easily provide such an impact. This is illustrated in a
toy model, which allows analytical consideration, and then in the full model
using Monte Carlo simulations. The resulting velocity field is very close to
that provided by the non-relativistic model of motion. The obtained bulk flow
velocity is consistent with {\Lambda}CDM cosmology.Comment: 10 pages, 3 figures, 2 table
COVAD survey 2 long-term outcomes: unmet need and protocol
Vaccine hesitancy is considered a major barrier to achieving herd immunity against COVID-19. While multiple alternative and synergistic approaches including heterologous vaccination, booster doses, and antiviral drugs have been developed, equitable vaccine uptake remains the foremost strategy to manage pandemic. Although none of the currently approved vaccines are live-attenuated, several reports of disease flares, waning protection, and acute-onset syndromes have emerged as short-term adverse events after vaccination. Hence, scientific literature falls short when discussing potential long-term effects in vulnerable cohorts. The COVAD-2 survey follows on from the baseline COVAD-1 survey with the aim to collect patient-reported data on the long-term safety and tolerability of COVID-19 vaccines in immune modulation. The e-survey has been extensively pilot-tested and validated with translations into multiple languages. Anticipated results will help improve vaccination efforts and reduce the imminent risks of COVID-19 infection, especially in understudied vulnerable groups
Variation in organic and mineral components in young Eucalyptus seedlings under saline stress
36 ref.International audienc
Detection of Uranium Contamination in Acacia Cell Sap by Capillary Zone Electrophoresis (CZE) Technique
The study was carried out to detect uranium level in the cell sap of acacia plant cells, for this purpose callus cultures of Acacia albida was used as well as plants. Cell saps from both callus and plant leaf were taken using Micro capillary syringe and detected using Capillary zone electrophoresis technique. It was shown that using citrate buffer of 3.0pH help in detecting uranium accumulated in the cells. Prospective calculation for the level of uranium uptake showed that 1.64mM is the level of uranium in the leaf cells that had been grown on soil with addition of 500 mg.kg-1 uranyl nitrate for 3 months, while for callus which grown on MS medium with addition of 500 mg/l uranyl nitrate for the same time (3 months), uptake of uranium reached 0.8 mM. The comparison between TXRF analysis of uranium accumulated in plant tissues and CZE efficiency in detecting uranium level in cell sap of both leaves and callus cells, it was shown that both techniques prove that A.albida plants can accumulate uranium with a level double as that taken by callus cells