University of Nebraska–Lincoln

About: University of Nebraska–Lincoln is a education organization based out in Lincoln, Nebraska, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 28059 authors who have published 61544 publications receiving 2139104 citations. The organization is also known as: Nebraska & UNL.

Resolving Weak Light of Sub-picowatt per Square Centimeter by Hybrid Perovskite Photodetectors Enabled by Noise Reduction.

Abstract: A highly sensitive hybrid perovskite photodetector is demonstrated to be able to directly resolve light irradiance down to sub-picowatts per square centimeter, in good accordance with the calculated noise equivalent power, which is enabled by electron and hole transport layer engineering, especially the trap passivation effect of the double fullerene layer.

Drought Monitoring with NDVI-Based Standardized Vegetation Index

Abstract: Drought is one of the major natural hazards affecting the environment and economy of countries worldwide. Reliance on weather data alone is not sufficient to monitor areas of drought, particularly when these data can be untimely, sparse, and incomplete. Augmenting weather data with satellite images to identify the location and severity of droughts is a must for complete, up-to-date, and comprehensive coverage of current drought conditions. The objective of this research was to standardize, by time of year, the Normalized Difference Vegetation Index (NDVT) to augment drought-monitoring techniques. The Standardized Vegetation Index (SVI) describes the probability of vegetation condition deviation from "normal," based on calculations from weekly NDvI values. The study was conducted with 12 years (1989-2000) of Advanced Very High-Resolution Radiometer (AVHRR) satellite images. Z-scores of the NDVI distribution are used to estimate the probability of occurrence of the present vegetation condition at a given location relative to the possible range of vegetative vigor, historically. The ~VI can be interpreted as vegetation condition based on the fact that vegetation is an efficient integrator of climatic and anthropogenic impacts in the boundary layer of the atmosphere. It thereby provides a spatially and temporally continuous short-term indicator of climatic conditions. Findings indicate that the svr, along with other drought monitoring tools, is useful for assessing the extent and severity of drought at a spatial resolution of 1 km. The SVI is capable of providing a near-real-time indicator of vegetation condition within drought regions, and more specifically areas of varying drought conditions.

Variance and the value of information

Abstract: A simple way to approximate the value of information is proposed. This approximation suggests that two kinds of quantities are important in determining the value of information: (1) the optimal behaviors that would be chosen if the decision maker knew which subtype (or state) of the resource it faced; and (2) the costs of small deviations from these subtype optima. I show that the value of information is approximately equal to the product of the mean cost of small deviations from the subtype optima and the variance of a modified distribution of the optimal behaviors. This helps to resolve the conflict between a result from economics, which shows that the value of information does not increase with the variance of subtypes, and results from theoretical behavioral ecology, which show that the effect of adding incomplete information to "conventional" models is greatest when the variance of subtypes is greatest. There is no conflict here as long as an increase in the variance of subtypes results in an increas...