Search results for "Daytime"
showing 10 items of 61 documents
Medico-legal implications of sleep apnoea syndrome: driving license regulations in Europe.
2008
Background: Sleep apnoea syndrome (SAS), one of the main medical causes of excessive daytime sleepiness, has been shown to be a risk factor for traffic accidents. Treating SAS results in a normalized rate of traffic accidents. As part of the COST Action B-26, we looked at driving license regulations, and especially at its medical aspects in the European region. Methods: We obtained data from Transport Authorities in 25 countries (Austria, AT; Belgium, BE; Czech Republic, CZ; Denmark, DK; Estonia, EE; Finland, FI; France, FR; Germany, DE; Greece, GR; Hungary, HU; Ireland, IE; Italy, IT; Lithuania, LT; Luxembourg, LU; Malta, MT; Netherlands, NL; Norway, EC; Poland, PL; Portugal, PT; Slovakia,…
Change in weight and central obesity by positive airway pressure treatment in obstructive sleep apnea patients: longitudinal data from the ESADA coho…
2018
The effect of positive airway pressure treatment on weight and markers of central obesity in patients with obstructive sleep apnea remains unclear. We studied the change in body weight and anthropometric measures following positive airway pressure treatment in a large clinical cohort. Patients with obstructive sleep apnea with positive airway pressure treatment from the European Sleep Apnea Database registry (n = 1, 415, 77% male, age 54 ± 11 [mean ± SD] years, body mass index 31.7 ± 6.4 kg/m2, apnea–hypopnea index 37 ± 24 n per hr, Epworth Sleepiness Scale 10.2 ± 5.0) were selected. Changes in body mass index and neck/waist/hip circumferences at baseline and at follow-up visit were analyse…
Daytime sensible heat flux estimation over heterogeneous surfaces using multitemporal land-surface temperature observations
2016
Equations based on surface renewal (SR) analysis to estimate the sensible heat flux (H) require as input the mean ramp amplitude and period observed in the ramp-like pattern of the air temperature measured at high frequency. A SR-based method to estimate sensible heat flux (HSR-LST) requiring only low-frequency measurements of the air temperature, horizontal mean wind speed, and land-surface temperature as input was derived and tested under unstable conditions over a heterogeneous canopy (olive grove). HSR-LST assumes that the mean ramp amplitude can be inferred from the difference between land-surface temperature and mean air temperature through a linear relationship and that the ramp freq…
Unusually high frequency natural VLF radio emissions observed during daytime in Northern Finland
2016
Geomagnetic field variations and electromagnetic waves of different frequencies are ever present in the Earth's environment in which the Earth's fauna and flora have evolved and live. These waves are a very useful tool for studying and exploring the physics of plasma processes occurring in the magnetosphere and ionosphere. Here we present ground-based observations of natural electromagnetic emissions of magnetospheric origin at very low frequency (VLF, 3–30 kHz), which are neither heard nor seen in their spectrograms because they are hidden by strong impulsive signals (sferics) originating in lightning discharges. After filtering out the sferics, peculiar emissions are revealed in these dig…
On the relationship between the sky view factor and the land surface temperature derived by Landsat-8 images in Bari, Italy
2015
This study investigates the impact of landscape composition and urban morphology on land surface temperature LST in the city of Bari, Italy. For this purpose, correlation between sky view factor SVF and LST was done assigning weights to the output results and moreover expressing the latter according to the four main surface classes of the Corine land cover CLC classification method. To do this, several daytime Landsat 8 and night-time Landsat 7 ETM+ images acquired during different months of the year were used to retrieve LST by using the radiative transfer equation. The results show a positive relationship between LST and SVF, and this trend is emphasized particularly in the more dense urb…
Land surface air temperature retrieval from EOS-MODIS images
2014
The knowledge of the spatial and temporal patterns of surface air temperature (SAT) is essential to monitor a region's climate and meteorology, to quantify surface exchange processes, to improve climatic and meteorological model results, and to study health and economic impacts. This letter analyzed correlations between SAT and geophysical land surface variables, mainly land surface temperature (LST), to establish operative techniques to obtain spatially continuous land SAT maps from satellite data, unlike data provided by meteorological station networks. The correlations were analyzed by using EOS-MODIS images, meteorological station network data, and geographical variables. Linear regress…
Development of a general model to estimate the instantaneous, daily, and daytime net radiation with satellite data on clear-sky days
2015
Net radiation is a key variable in computing evapotranspiration and is a driving force in many other physical and biological processes. Remote sensing techniques provide an unparalleled spatial and temporal coverage of land-surface attributes, and thus several studies have attempted to estimate net radiation by combining remote sensing observations with surface and atmospheric data. However, remote sensing provides instantaneous data, when many applications and models need information at other temporal scales. In this work, a new general methodology is proposed to estimate daily and daytime net radiation and to retrieve the diurnal cycle of net radiation. Four images were acquired on differ…
Evaluation of Terra/MODIS atmospheric profiles product (MOD07) over the Iberian Peninsula: a comparison with radiosonde stations
2014
Remote sensing techniques are a useful tool for continuous observation of the Earth at global scale. However, products derived from remote sensing data require a rigorous validation using in situ data. Moderate Resolution Imaging Spectroradiometer (MODIS) is not really a sounding instrument, but it does have 16 infrared bands (bands 20–36 covering the spectral range from 3 µm to 14 µm) that allow the retrieval of temperature and moisture profiles as well as total column integrated magnitudes. In this paper we show the results obtained in the evaluation of MOD07 daytime and nighttime products over the Iberian Peninsula during the decade from 2000 to 2010 using nine radiosonde stations. Altho…
Angular variations of brightness surface temperatures derived from dual-view measurements of the Advanced Along-Track Scanning Radiometer using a new…
2019
Abstract Surface temperatures derived from remote sensing data over heterogeneous, non-isothermal land surfaces depend on the viewing and solar angles mainly due to variations in sunlit and shaded fractions of the different elements in the field of view. The near-simultaneous dual-view capability of the Advanced Along-Track Scanning Radiometer (AATSR) can be used to estimate differences in brightness surface temperatures (BSTs) between the nadir (satellite zenith angle of 0°–21.7°) and forward views (53°–55.6°) in the 11 and 12 μm bands. BST is defined as the black-body temperature corresponding to the radiance at surface level (that is, corrected for atmospheric absorption and emission). W…
Analyzing the anisotropy of thermal infrared emissivity over arid regions using a new MODIS land surface temperature and emissivity product (MOD21)
2015
Abstract The MOD21 Land Surface Temperature and Emissivity (LST&E) product will be included in forthcoming Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6. Surface temperature and emissivities for thermal bands 29 (8.55 μm), 31 (11 μm) and 32 (12 μm) will be retrieved using the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Temperature and Emissivity Separation (TES) method adapted to MODIS at-sensor spectral radiances, previously corrected with the Water Vapor Scaling method (MOD21 algorithm). We simulated MOD21 product estimates over two different sandy deserts (i.e. White Sands and Great Sands) using a series of MODIS scenes from 2010 to 2013. T…