Competing epidemics on complex networks

Human diseases spread over networks of contacts between individuals and a substantial body of recent research has focused on the dynamics of the spreading process. Here we examine a model of two competing diseases spreading over the same network at the same time, where infection with either disease gives an individual subsequent immunity to both. Using a combination of analytic and numerical methods, we derive the phase diagram of the system and estimates of the expected final numbers of individuals infected with each disease. The system shows an unusual dynamical transition between dominance of one disease and dominance of the other as a function of their relative rates of growth. Close to this transition the final outcomes show strong dependence on stochastic fluctuations in the early stages of growth, dependence that decreases with increasing network size, but does so sufficiently slowly as still to be easily visible in systems with millions or billions of individuals. In most regions of the phase diagram we find that one disease eventually dominates while the other reaches only a vanishing fraction of the network, but the system also displays a significant coexistence regime in which both diseases reach epidemic proportions and infect an extensive fraction of the network.Comment: 14 pages, 5 figure

POTENTIAL EFFECTS OF SUBSIDIZED LIVESTOCK INSURANCE ON LIVESTOCK PRODUCTION

Recent legislation has cleared the way for subsidized livestock price insurance. Such programs could increase production. Expected feeder cattle prices with and without subsidized insurance will be analyzed using E-V and Stochastic Dominance. Results will highlight the potential effects of the program on marketing risk and production decisions.Livestock Production/Industries, Risk and Uncertainty,

Bedrock Geology of Cedar County, Iowa Final Phase: Bedrock Geologic Map of Cedar County 1:100,000

https://ir.uiowa.edu/igs_ofm/1060/thumbnail.jp

Vortex Formation by Interference of Multiple Trapped Bose-Einstein Condensates

We report observations of vortex formation as a result of merging together multiple $^{87}$Rb Bose-Einstein condensates (BECs) in a confining potential. In this experiment, a trapping potential is partitioned into three sections by a barrier, enabling the simultaneous formation of three independent, uncorrelated condensates. The three condensates then merge together into one BEC, either by removal of the barrier, or during the final stages of evaporative cooling if the barrier energy is low enough; both processes can naturally produce vortices within the trapped BEC. We interpret the vortex formation mechanism as originating in interference between the initially independent condensates, with indeterminate relative phases between the three initial condensates and the condensate merging rate playing critical roles in the probability of observing vortices in the final, single BEC.Comment: 5 pages, 3 figure

Theoretical and Practical Capacities of Transit Modes

The transporting capacities of diff­erent transit modes are often discussed, but values quoted for different modes vary widely because of differing assump­tions. This paper presents the basic theory of capacity and gives explanation of and insight to three aspects which must be carefully considered in capacity analysis: Way capacity and station capacity of transit modes usually vary greatly; Capacity must be considered together\u27 with service quality, primarily oper­ating safety and speed; and There is a considerable difference b-tween theoretical and practical ·capacities of modes: the latter are important for design.

Bedrock geology of southeast Iowa, Digital geologic map of Iowa, Phase 7: Southeast Iowa

https://ir.uiowa.edu/igs_ofm/1032/thumbnail.jp

Bedrock Geologic Map of Iowa

https://ir.uiowa.edu/igs_ofm/1070/thumbnail.jp

Homophobia and Sport Experience: A Survey of College Students

Athlete (n = 246) and nonathlete (n = 135) students (381 total) from a mid-sized, rural university completed the Attitudes Towards lesbians and Gay Men Scale (ATLG; Herek, 1984). Average ratings for attitudes toward and perceptions of gay men and lesbians ranged from negative to mixed. Females scored significantly lower on homophobia than males, while athletes rated sigriificantly higher on homophobia than nonathletes. The results suggest that athletes, at least those from primarily rural areas, have less tolerance for lesbians and gay men than nonathletes. Results and implications for counselors are discussed in the context of the conservatism of athletics, sport as an arena of masculinity, heterosexism, lack of knowledge about lesbians and gay men, and other sociocultural influences

Knowledge of AIDS and Risky Sexual Behaviors among Athletes

This research investigated sexual behaviors and AIDS knowledge for 381 students, athletes (n=246) and nonathletes (n=135), at a rural university. Nonathletes and athletes scored similarly on an AIDS knowledge test, but differed in reported risky sexual behavior. Athletes reported more behavioral changes after Magic Johnson's HIV-related retirement, but they still reported having more sexual partners per year than did nonathletes. The groups did not differ in condom use. By engaging in such risky behaviors, athletes may be more susceptible to sexually transmitted diseases like AIDS. Athletes (and nonathletes) continue to engage in unsafe sexual behaviors even while in possession of adequate knowledge of the risks. These results support previous research that has found that knowledge is not a valid predictor of sexual behavior (Ehde et al., 1995; Hays & Hays, 1992, Walters, 1992). Implications for athletic counselors were discussed

Iowa\u27s Sand Prairie State Preserves: Anomalous Grain-Size Distributions and Optically Stimulated Luminescence (OSL) Dates

Grain-size distributions and optically stimulated luminescence (OSL) dates were obtained for the sand from Iowa\u27s five sand prairie state preserves, which are Behren\u27s Ponds and Woodland, Cedar Hills Sand Prairie, Kish-Ke-Kosh Prairie, Marietta Sand Prairie and Rock Island. OSL dates ranged from the late Pleistocene (15,560 years B.P.) to the very late Holocene (as recent as 590 years B.P.), indicating that the late Pleistocene and Holocene Epochs in Iowa have seen multiple episodes of aridity, which is consistent with results from the Nebraska Sand Hills and eolian sand stringers in southeastern Minnesota. The grain-size distributions were anomalous in that, compared with typical eolian deposits, the transition grain sizes between the traction I saltation populations and saltation I suspension populations were shifted toward coarser grains, and the percentage of sand in the suspension population was high. The anomalous grain-size distributions could not be explained by post-depositional weathering or poor sorting in the source region, but were consistent with the eolian transport of sand through grass prior to deposition. It is suggested that the anomalous grain-size distribution could be one of a set of criteria for distinguishing paleo-sand prairies from other buried bodies of eolian sand or sandstone