Flood hazards studies in the Mississippi River basin using remote sensing

The Spring 1973 Mississippi River flood was investigated using remotely sensed data from ERTS-1. Both manual and automatic analyses of the data indicated that ERTS-1 is extremely useful as a regional tool for flood mamagement. Quantitative estimates of area flooded were made in St. Charles County, Missouri and Arkansas. Flood hazard mapping was conducted in three study areas along the Mississippi River using pre-flood ERTS-1 imagery enlarged to 1:250,000 and 1:100,000 scale. Initial results indicate that ERTS-1 digital mapping of flood prone areas can be performed at 1:62,500 which is comparable to some conventional flood hazard map scales

Satellite microwave observations of soil moisture variations

The electrically scanning microwave radiometer (ESMR) on the Nimbus 5 satellite was used to observe microwave emissions from vegetated and soil surfaces over an Illinois-Indiana study area, the Mississippi Valley, and the Great Salt Lake Desert in Utah. Analysis of microwave brightness temperatures (T sub B) and antecedent rainfall over these areas provided a way to monitor variations of near-surface soil moisture. Because vegetation absorbs microwave emission from the soil at the 1.55 cm wavelength of ESMR, relative soil moisture measurements can only be obtained over bare or sparsely vegetated soil. In general T sub B increased during rainfree periods as evaporation of water and drying of the surface soil occurs, and drops in T sub B are experienced after significant rainfall events wet the soil. Microwave observations from space are limited to coarse resolutions (10-25 km), but it may be possible in regions with sparse vegetation cover to estimate soil moisture conditions on a watershed or agricultural district basis, particularly since daily observations can be obtained

Passive microwave applications to snowpack monitoring using satellite data

Nimbus-5 Electrically Scanned Microwave Radiometer data were analyzed for the fall of 1975 and winter and summer of 1976 over the Arctic Coastal Plain of Alaska to determine the applicability of those data to snowpack monitoring. It was found that when the snow depth remained constant at 12.7 cm, the brightness temperatures T sub B varied with air temperature. During April and May the production of ice lenses and layers within the snow, and possibly wet ground beneath the snow contribute to the T sub B variations also. Comparison of March T sub B values of three areas with the same (12.7 cm) snow depth showed that air temperature is the predominant factor controlling the T sub B differences among the three areas, but underlying surface conditions and individual snowpack characteristics are also significant factors

Studies of snowpack properties by passive microwave radiometry

Research involving the microwave characteristics of snow was undertaken in order to expand the information content currently available from remote sensing, namely the measurement of snowcovered area. Microwave radiation emitted from beneath the snow surface can be sensed and thus permits information on internal snowpack properties to be inferred. The intensity of radiation received is a function of the average temperature and emissivity of the snow layers and is commonly referred to as the brightness temperature (T sub B). The T sub B varies with snow grain and crystal sizes, liquid water content, and snowpack temperature. The T sub B of the 0.8 cm wavelength channel was found to decrease more so with increasing snow depth than the 1.4 cm channel. More scattering of the shorter wavelength radiation occurs thus resulting in a lower T sub B for shorter wavelengths in a dry snowpack. The longer 21.0 cm wavelength was used to assess the condition of the underlying ground

Snow water equivalent determination by microwave radiometry

One of the most important parameters for accurate snowmelt runoff prediction is snow water equivalent (SWE) which is contentionally monitored using observations made at widely scattered points in or around specific watersheds. Remote sensors which provide data with better spatial and temporal coverage can be used to improve the SWE estimates. Microwave radiation, which can penetrate through a snowpack, may be used to infer the SWE. Calculations made from a microscopic scattering model were used to simulate the effect of varying SWE on the microwave brightness temperature. Data obtained from truck mounted, airborne and spaceborne systems from various test sites were studied. The simulated SWE compares favorable with the measured SWE. In addition, whether the underlying soil is frozen or thawed can be discriminated successfully on the basis of the polarization of the microwave radiation

Hydrologic applications of Nimbus 5 ESMR data

A region of low brightness temperature lying along the Mississippi River from Cairo, Illinois, to Morganza, Louisiana was observed in early Nimbus 5 Electrically Scanning Microwave Radiometer images. This region, which generally corresponds to an outwash aquifer in the Mississippi Valley, had brightness temperatures, at times as much as 40 K below the surrounding (drier) older uplands. Fluctuations of as much as 30 K were observed during the time interval 15 December 1972 to 28 February 1973. Comparison images taken from the Earth Resources Technology Satellite indicate that the study area is aligned with the Mississippi River floodplain, a region of potentially high soil moisture content. The brightness temperature fluctuations were compared with variations in precipitation and other hydrologic parameters in order to delineate the causative factors

ПРОБЛЕМИ ФОРМУВАННЯ ЕФЕКТИВНОГО ІМІДЖУ В СУЧАСНІЙ ПОЛІТОЛОГІЇ

Проаналізовані поняття та структура політичного іміджу, визначені компоненти ефективного іміджу політика, виділені складові елементи та закономірності побудови сучасної іміджевої стратегії.Analyzed the concept and structure of political image, the image identified components of effective policy, special elements and patterns of modern image strategy

Cognitive performance in elderly patients undergoing carotid endarterectomy or carotid artery stenting: A twelve-month follow-up study

Background: It is still a matter of debate if and to what extent carotid endarterectomy (CEA) and carotid artery stenting (CAS) impair cognitive functioning in the elderly. Methods: We conducted a nonrandomized clinical trial on subjects with asymptomatic carotid artery stenosis comparing CEA (n = 28; 24 males and 4 females; 72.6 ± 5.8 years old) with CAS (n = 29; 17 males and 12 females; 75.1 ± 5.7 years old). Cognition, mood and functional status were evaluated by a broad spectrum of tests performed on the day prior to carotid reopening as well as 3 and 12 months after. Results: No significant differences in scores on cognitive tests including the Babcock story recall test and Rey's auditory verbal learning test (memory), category naming test (verbal fluency), trail-making test parts A and B (attention and executive function) and controlled oral word association test (executive functioning) were observed 3 and 12 months after carotid reopening independent of the technique used. Only scores on the copy drawing test (visuospatial and constructional abilities) slightly but significantly (p < 0.05) worsened in the CAS group 12 months after the intervention. No significant differences between the CEA and CAS groups were detected regarding mood and functional status after 3 and 12 months. Conclusions: CEA and CAS seem to be safe procedures in elderly patients in terms of cognitive, mood and functional status in the short and long term. CAS might be preferred for the shorter hospital stay, but further studies with a larger number of old and oldest old subjects with a longer follow-up are needed to better understand the cost-effectiveness of both treatments

Lactate detection in the brain of growth-restricted fetuses with magnetic resonance spectroscopy

OBJECTIVE: The objective of the study was to determine the feasibility of detecting fetal brain lactate, a marker of fetal metabolic acidemia, using a noninvasive technique, proton magnetic resonance spectroscopy (1H MRS), in intrauterine growth-restricted (IUGR) fetuses. STUDY DESIGN: In vivo human fetal brain lactate detection was determined by 1H MRS in 5 fetuses with IUGR. Oxygenation and acid-base balance data were obtained at birth. RESULTS: 1H MRS analysis showed the presence of a lactate peak in the brain of the most severely affected IUGR fetus, with abnormal umbilical artery Doppler and fetal heart rate tracing. This finding was consistent with the low oxygen content and high lactic acid concentration observed in umbilical blood obtained at delivery. CONCLUSION: 1H MRS allows the noninvasive detection of cerebral lactate in IUGR fetuses. Lactate detected by 1H MRS may represent a possible marker of in utero cerebral injury or underperfusion