Lane Curvature Research Articles

Evaluating the impact of passengers on the safety of older drivers

Problem: This study involved a quasi-induced exposure analysis of 4 years of crashes involving older drivers in the state of Kentucky. Method: Single- and multivehicle crashes were disaggregated according to the number of passengers: (a) no passenger, (b) one passenger, and (c) two or more passengers. Results: Overall, the presence of two or more passengers was found to negatively impact the probability that drivers 75 years of age or older were at fault in crashes. Several potential factors were studied for interactive effects with passengers: vehicle occupant gender mix, time of the day, road curvature, grade, and number of lanes. The negative impact of passengers increased for some geometric road conditions. However, older drivers were found to be safer at night when carrying two or more passengers. The presence or absence of passengers was not found to affect the 65- to 74-year-old driver group. Groups of male vehicle occupants with a 75+ male driver were found to have high single-vehicle crash rates. Impact: These results are among the first to directly consider the effect of passengers on the crash-causing propensity of older drivers and the findings suggest more work is warranted to consider causes for the crash rate differences.

Measurement of Jupiter's decametric radio source parameters by the modulation lane method

In previously published works we have developed a model to explain the production of modulation lanes in the dynamic spectra of Jupiter's decametric emission. In this paper we use the model with newly available data to test the model and to measure emission source and beam parameters. Some of the data were wideband, providing for the first time the opportunity to verify the accuracy of the model in fitting the considerable lane curvature exhibited in such a case. Relatively precise measurements of the cone half‐angle of hollow‐cone beam and other source and beam parameters of Io‐B radiation were also made possible by the wideband data. Narrowband data enabled us to measure for the first time the beam cone half‐angle for non‐Io‐A radiation. The measured cone half‐angles for the two sources were both within ∼2° or 3° of 60°. This measurement is consistent with the long‐held idea that the sources Io‐B, Io‐A, and non‐Io‐A are due to the same rotating hollow‐cone beam and that the only difference between the latter two is the intensification of Io‐A radiation by the connection with Io in comparison with that of non‐Io‐A. We also measured the cone half‐angle for S bursts and found it to be less than that of the much more common L bursts.

Computer assisted size measurement on a digitising tablet of nucleic acid and protein molecules from gels

A method is presented for the rapid and convenient determination of molecular weight or chain length of macromolecules from their electrophoretic mobility in gels, using a computer-controlled digitising tablet. A novel feature is accurate compensation for ‘smile’ or ‘frown’ profiles as well as for the possible splay or curvature of lanes. A family of monotonic, asymptotic, generalised quadratics is calculated to fit locally the known values in a marker track, and a weighting function is then applied to these enveloping curves so that the prediction algorithm simulates the interpolation of unknown values from a smooth graph drawn through the known bands. Results for double stranded DNA, single and double stranded RNA, and protein molecules are given. The average error of the predicted values against the known molecular sizes was 0.2% for dsDNA, 1.7% for dsRNA, 0.7% for ssRNA and 3.6% for protein molecules.

Two computer programs for rapid entry of DNA sequence data.

Two computer programs for the IBM personal computer are described for rapid and accurate entry of DNA sequence data. The DNA sequence files produced can be used directly by the DNA sequence manipulation programs by R. Staden (the DataBase system), the University of Wisconsin Genetics Computer Group, DNASTAR, or D.Mount. The first program, DIGISEQ, utilizes a sonic digitizer for semi-automation of sequence entry. To enter the DNA sequence each band of a gel reading is touched by the stylus of the sonic digitizer. DIGISEQ corrects for both changes in lane width and lane curvature. The algorithm is extremely efficient and rarely requires re-entering the centers of the lanes. The second program, TYPESEQ, uses only the keyboard for input. The keyboard is reconfigured to place nucleotides and ambiguity codes under the fingers of one hand, corresponding to the order of the nucleotides on the gel defined by the user. Both programs produce individual tones for each nucleotide, and certain ambiguity codes. This verifies input of the correct nucleotide or ambiguity code, and thus eliminates the need to visually check the screen display during sequence entry.