A queueing model of pilot decision making in a multi-task flight management situation

Allocation of decision making responsibility between pilot and computer is considered and a flight management task, designed for the study of pilot-computer interaction, is discussed. A queueing theory model of pilot decision making in this multi-task, control and monitoring situation is presented. An experimental investigation of pilot decision making and the resulting model parameters are discussed

The Effect of Food Deserts on the Body Mass Index of Elementary School Children

Families in low-income neighborhoods sometimes lack access to supermarkets that provide a broad range of healthy foods. We investigate whether these so called "food deserts" play a role in childhood obesity using a statewide panel data set of Arkansas elementary schoolchildren. We use fixed-effects panel data regression models to estimate the average food desert effect. We next compare children who left (entered) food deserts to children who were always (never) in food deserts and homogenize samples for those whose food desert status changed as a result of a change in residence and those whose status changed only as a consequence of the entry or exit of a supermarket. We present evidence that exposure to food deserts is associated with higher z-scores for body mass index. On average, this is in the neighborhood of 0.04 standard deviations. The strongest evidence and largest association is among urban students and especially those that transition into food deserts from non-deserts. Our food desert estimates are similar in magnitude to findings reported in earlier work on diet and lifestyle interventions targeting similarly aged schoolchildren. That said, we are unable to conclude that the estimated food desert effect is causal because many of the transitions into or out of food deserts result from a change in residence, an event that is endogenous to the child's household. However, there is evidence that food deserts are a risk indicator and that food desert areas may be obesogenic in ways that other low-income neighborhoods are not

The Passive Microwave Remote Sensing of Soil Moisture: the Effect of Tilled Row Structure

The tilled rowstructure is known to be one of the important factors affecting the observations of the microwave emission from a natural surface. Measurements of this effect were carried out with both I and X band radiometers mounted on a mobile truck on a bare 40 m x 45 m row tilled field. The soil moisture content during the measurements ranged from approximately 10 percent to approximately 30 percent by dry weight. The results of these measurements showed that the variations of the antenna temperatures with incident angle theta changed with the azimuthal angle a measured from the row direction. A numerical calculation based on a composite surface roughness was made and found to predict the observed features within the model's limit of accuracy. It was concluded that the difference between the horizontally and vertically polarized temperatures was due to the change in the local angle of field emission within the antenna field of view caused by the large scale row structure

Using Yield Trial Data to Make Variety Selections

Each year I receive several questions about how best to use yield trial data to make hybrid and variety selection decisions. This article will cover the most common issues that are discussed

2011 Iowa Crop Performance Tests for Corn and Soybean

Final results of the 2011 Iowa Crop Performance Tests for corn and soybeans are now available online at the Iowa State University Crop Testing website and asdownloadable publications from the ISU Extension Online Store. All single-location and district data are available for online viewing and can also be downloaded as Excel files from the crop testing site

A fresh view of variety selection

Integrating soybean variety selection with soybean pest management strategies seems like a simple task. Many pest management strategies tout variety selection as a key component of pest management. Variety selection is not, however, quite as simple as choosing the best one. Difficulty arises in identifying which data reports should be used. Using the proper information will allow you to make better variety selection decisions and improve your profitability

Genetic diversity among progenitors and derived lines of two maize (Zea mays L.) populations

Forty-six inbreds related to Iowa Stiff Stalk Synthetic (BSSS) and Iowa Corn Borer Synthetic #1 (BSCB1) were assayed for polymorphism at 227 microsatellite loci. The inbreds consisted of progenitors of BSSS and BSCB1 as well as elite lines derived from those populations. Diversity statistics were used to estimate genetic variability among the derived lines, and to locate regions of the maize genome that have changed as a result of artificial selection. The four groups of germplasm were labeled CBP and SSP for the progenitors of BSCB1 and BSSS, respectively, and CBL and SSL for the lines derived from BSCB1 and BSSS, respectively.;There were means of 3.5 and 3.4 alleles per locus among the CBP and SSP, respectively, and 2.3 and 2.5 alleles per locus among the CBL and SSL. As expected, many more alleles were found in the progenitor groups than in the groups of derived lines. CBL showed only 60% of the alleles found in CBP, while SSL had 66% of the alleles found in SSP. Supporting previous studies in this area, we found that 26% of the alleles in SSP were unique to a single inbred. In CBP, 32% of the alleles were unique, a figure slightly higher than previous results in BSCB1 or BSSS. Of the unique alleles in both progenitor groups, 73% were not found in any of the derived lines. There were 33 marker loci in BSSS and 18 marker loci in BSCB1 that exhibited reductions in gene diversity that can be attributed to artificial selection (P = 0.1).;Genetic distance between the progenitor groups was very low, indicating the progenitors were not highly divergent from each other. Rogers\u27s distance (RD) between progenitor groups and derived line groups was identical in both BSSS and BSCB1, suggesting that the derived lines are equally divergent from their respective progenitor groups. The largest RD was between the two derived-line groups, about 35% greater than the progenitor-to-derived line distance. Rogers\u27s distance between individual derived lines ranged from 15 to 54 in SSL and 25 to 56 in CBL, indicating some of the derived lines are very closely related

Iowa Crop Performance Tests

The Iowa Crop Performance Tests (ICPT) are conducted each year to provide information farmers need to select the best varieties or hybrids for their production conditions. The Southeast Research Farm (SERF) has hosted these soybean experiments each year since 2005, and two corn experiments since 2009. This information and more can be downloaded from www.croptesting.iastate.edu

Iowa Crop Performance Test—Soybeans

The Iowa Crop Performance Test—Soybeans is conducted each year to provide information farmers need to select the best varieties or brands for their production conditions. Seed companies, Iowa farmers, and the Iowa Crop Improvement Association may include entries in these tests. The experiments grown in 2005 at the Southeast Research Farm were planted May 11 and harvested October 5. One test evaluated 16 lines of soybeans treated with conventional herbicide and another test evaluated 75 lines of Roundup® Ready (RR) beans

Psychological Issues in Online Adaptive Task Allocation

Adaptive aiding is an idea that offers potential for improvement over many current approaches to aiding in human-computer systems. The expected return of tailoring the system to fit the user could be in the form of improved system performance and/or increased user satisfaction. Issues such as the manner in which information is shared between human and computer, the appropriate division of labor between them, and the level of autonomy of the aid are explored. A simulated visual search task was developed. Subjects are required to identify targets in a moving display while performing a compensatory sub-critical tracking task. By manipulating characteristics of the situation such as imposed task-related workload and effort required to communicate with the computer, it is possible to create conditions in which interaction with the computer would be more or less desirable. The results of preliminary research using this experimental scenario are presented, and future directions for this research effort are discussed