2,313 research outputs found
Wind-Wave induced velocity in ATI SAR Ocean Surface Currents: First experimental evidence from an airborne campaign
Conventional and along-track interferometric (ATI) Synthetic Aperture Radar (SAR) sense the motion of the ocean surface by measuring the Doppler shift of reflected signals. Measurements are affected by a Wind-wave induced Artefact Surface Velocity (WASV) which was modelled theoretically in past studies and has been estimated empirically only once before with Envisat ASAR by Mouche et al., (2012). An airborne campaign in the tidally dominated Irish Sea served to evaluate this effect and the current retrieval capabilities of a dual-beam SAR interferometer known as Wavemill. A comprehensive collection of Wavemill airborne data acquired in a star pattern over a well-instrumented validation site made it possible for the first time to estimate the magnitude of the WASV, and its dependence on azimuth and incidence angle from data alone. In light wind (5.5 m/s) and moderate current (0.7 m/s) conditions, the wind-wave induced contribution to the measured ocean surface motion reaches up to 1.6 m/s upwind, with a well-defined 2nd order harmonic dependence on direction to the wind. The magnitude of the WASV is found to be larger at lower incidence angles. The airborne WASV results show excellent consistency with the empirical WASV estimated from Envisat ASAR. These results confirm that SAR and ATI surface velocity estimates are strongly affected by WASV and that the WASV can be well characterized with knowledge of the wind knowledge and of the geometry. These airborne results provide the first independent validation of Mouche et al., 2012, and confirm that the empirical model they propose provides the means to correct airborne and spaceborne SAR and ATI SAR data for WASV to obtain accurate ocean surface current measurements. After removing the WASV, the airborne Wavemill retrieved currents show very good agreement against ADCP measurements with a root mean square error (RMSE) typically around 0.1 m/s in velocity and 10° in direction
Retinoic-Acid-Induced Downregulation of the 67 KDa Laminin Receptor Correlates with Reduced Biological Aggressiveness of Human Neuroblastoma Cells
16 pages (217-232), 6 figuresThe authors are indebted to Dr. S. Menard (Milan, Italy) for the gift of the antibody against 37LRP. C. M. R. L. was supported by Programa de Personal Técnico de Apoyo (PTA-2003-02-00207; Ministry of Education and Science, Spain). This work was supported by grants from the Spanish former Ministry of Education and Science and Ministry of Science and Innovation (SAF2003-00311, SAF2006–00647 and SAF2007–60780) and Generalitat Valenciana (GRUPOS 03/15 and ACOMP 09/212) (to D. B.) , and Instituto de Salud Carlos III (RD20-102 to S. N.).Peer reviewe
Melanotrope Secretory Cycle is Regulated by Physiological Inputs via the Hypothalamus
Previously, it has been shown that background color conditions regulate the
overall activity of the frog intermediate lobe by varying the proportions of the
two subtypes of melanotropes existing in the gland, the highly active or
secretory melanotropes and hormone-storage melanotropes, depending on
melanocyte-stimulating hormone ( -MSH) requirements. However, the factors
and mechanisms underlying these background-induced changes are still
unknown. In the present study, we investigated whether hypothalamic factors
known to regulate melanotrope cell function can induce changes in vitro similar
to those caused by background adaptation in vivo. We found that the inhibitors
apomorphine (a dopamine receptor agonist) and NPY decreased the number of
active melanotropes and increased simultaneously that of storage
melanotropes. On the other hand, the stimulator TRH increased the number of
active cells and concomitantly reduced that of storage cells. Inasmuch as none
of these treatments modified the apoptotic and proliferation rates in
melanotrope cells, it appears that these hypothalamic factors caused actual
interconversions of cells from a subpopulation to its counterpart. When taken
together, these findings suggest that the hypothalamus would control
melanotrope activity not only through short-term regulation of hormone
synthesis and release, but also through a long-term regulation of the secretory
phenotype of these cells whereby the activity of the intermediate lobe would be
adjusted to fulfill the hormonal requirements imposed by background
conditions
XMM-Newton Observation of an X-ray Trail Between the Spiral Galaxy NGC6872 and the Central Elliptical NGC6876 in the Pavo Group
We present XMM-Newton observations of a trail of enhanced X-rayemission
extending along the 8'.7 X 4' region between the spiral NGC6872 and the
dominant elliptical NGC6876 in the Pavo Group,the first known X-ray trail
associated with a spiral galaxy in a poor galaxy group and, with projected
length of 90 kpc, one of the longest X-ray trails observed in any system. The
X-ray surface brightness in the trail region is roughly constant beyond ~20 kpc
of NGC6876 in the direction of NGC6872. The trail is hotter (~ 1 keV) than the
undisturbed Pavo IGM (~0.5 keV) and has low metal abundances (0.2 Zsolar). The
0.5-2 keV luminosity of the trail, measured using a 67 X 90 kpc rectangular
region, is 6.6 X 10^{40} erg/s. We compare the properties of gas in the trail
to the spectral properties of gas in the spiral NGC6872 and in the elliptical
NGC6876 to constrain its origin. We suggest that the X-ray trail is either IGM
gas gravitationally focused into a Bondi-Hoyle wake, a thermal mixture of ~64%
Pavo IGM gas with ~36% galaxy gas that has been removed from the spiral NGC6872
by turbulent viscous stripping, or both, due to the spiral's supersonic motion
at angle xi ~ 40 degrees with respect to the plane of the sky, past the Pavo
group center (NGC6876) through the densest region of the Pavo IGM. Assuming xi
= 40 degrees and a filling factor eta in a cylindrical volume with radius 33
kpc and projected length 90 kpc, the mean electron density and total hot gas
mass in the trail is 9.5 X 10^{-4}*eta^{-1/2} cm^{-3} and 1.1 X
10^{10}*eta^{1/2} Msolar, respectively.Comment: typos corrected in Eq. 7 & 8, figures and discussion unchanged, 39
pages, 11 postscript figures, submitted to Ap
Axial Spondyloarthritis: Patient-Reported Impact in Europe
This open access book provides an overview of the International Map of Axial Spondyloarthritis (IMAS) project -focusing on Europe-, a wide-ranging, multi-disciplinary collaboration between academic groups, Health Care Professionals (HCPs), patient organizations and Novartis. IMAS was conceived to improve knowledge of Axial Spondyloarthritis (axSpA) and raise awareness of its heavy burden globally. By asking more than 2,000 patients across Europe about the impact of axSpA on multiple aspects of their life, the full extent of this disease was investigated from a direct patient perspective. This allowed a unique understanding of how living with axSpA affects the daily lives and well-being of patients, and how this varies between European countries. Axial Spondyloarthritis: Patient-Reported Impact in Europe highlights opportunities for progressing quality patient care to be applied to health services globally. HCPs, policy makers and patients will find this book to be an indispensable resource for improving the understanding of this chronic condition, including patients’ clinical outcomes, the protection of those at risk of psychological distress, and the economic burden on patients and society
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