Public health aspects of Tropical Storm Agnes in Virginia\u27s portion of Chesapeake Bay and its Tributaries

All Virginia waters within Chesapeake Bay were closed for the taking of shellfish for direct consumption on 23 June 1972. This initial closing was in anticipation of high microorganism levels accompanying flood waters moving downstream. Various areas beginning with the lower portion of Chesapeake Bay were reopened beginning )n 20 July 1972. By 5 October 1972 all areas closed as a result )f Tropical Storm Agnes were reopened. No increased incidents of infectious diseases caused by waterborne microorganisms were noted in Virginia which could be attributed to Tropical Storm Agnes.https://scholarworks.wm.edu/vimsbooks/1079/thumbnail.jp

Scaling of stiffness energy for 3d +/-J Ising spin glasses

Large numbers of ground states of 3d EA Ising spin glasses are calculated for sizes up to 10^3 using a combination of a genetic algorithm and Cluster-Exact Approximation. A detailed analysis shows that true ground states are obtained. The ground state stiffness (or domain wall) energy D is calculated. A D ~ L^t behavior with t=0.19(2) is found which strongly indicates that the 3d model has an equilibrium spin-glass-paramagnet transition for non-zero T_c.Comment: 4 pages, 4 figure

Application of the Unified Theory of Acceptance and Use of Technology Model to Predict Dental Students\u27 Behavioral Intention to Use Teledentistry

Abstract Teledentistry is an innovative technology that can be used to improve access to care and oral health outcomes. Dental students’ intention to use teledentistry after completing dental school has not been investigated. Purpose The unified theory of acceptance and use of technology (UTAUT) was used to predict intentions to use teledentistry among 4th-year U.S. dental students. Methods A cross-sectional approach was performed for a 7-week period in Spring 2019. All U.S. dental schools (N = 66) were invited to participate and 16 schools agreed to participate. An anonymous survey link was emailed to academic deans for dissemination to students. A total of 1416 4th-year dental students received the anonymous survey link and 210 students completed the survey (response rate = 14.8%). The survey included questions and scales that measured the UTAUT constructs of performance expectancy (PE), effort expectancy (EE), social influence (SI), facilitating conditions (FC), and behavioral intentions (BI). Data were analyzed using SPSS version 24. The study was deemed exempt by institutional review board. Results The dental students’ BI to use teledentistry was significantly predicted by PE (R2 = 33%, P \u3c 0.01), EE (R2 = 24%, P \u3c 0.01), SI (R2 = 24%, P \u3c 0.01), and FC (R2 = 14%, P \u3c 0.01). The UTAUT model was statistically significant in predicting the BI and explained 40% of BI variance (R2 = .40, P \u3c 0.01). Conclusions Dental students’ perceptions about PE, EE, SI, and FC were associated with BI. Therefore, exposure to teledentistry while in dental school could increase the likelihood of use as a practicing provider

A new method for analyzing ground-state landscapes: ballistic search

A ``ballistic-search'' algorithm is presented which allows the identification of clusters (or funnels) of ground states in Ising spin glasses even for moderate system sizes. The clusters are defined to be sets of states, which are connected in state-space by chains of zero-energy flips of spins. The technique can also be used to estimate the sizes of such clusters. The performance of the method is tested with respect to different system sizes and choices of parameters. As an application the ground-state funnel structure of two-dimensional +or- J spin glasses of systems up to size L=20 is analyzed by calculating a huge number of ground states per realization. A T=0 entropy per spin of s_0=0.086(4)k_B is obtained.Comment: 10 pages, 11 figures, 35 references, revte

Specific-Heat Exponent of Random-Field Systems via Ground-State Calculations

Exact ground states of three-dimensional random field Ising magnets (RFIM) with Gaussian distribution of the disorder are calculated using graph-theoretical algorithms. Systems for different strengths h of the random fields and sizes up to N=96^3 are considered. By numerically differentiating the bond-energy with respect to h a specific-heat like quantity is obtained, which does not appear to diverge at the critical point but rather exhibits a cusp. We also consider the effect of a small uniform magnetic field, which allows us to calculate the T=0 susceptibility. From a finite-size scaling analysis, we obtain the critical exponents \nu=1.32(7), \alpha=-0.63(7), \eta=0.50(3) and find that the critical strength of the random field is h_c=2.28(1). We discuss the significance of the result that \alpha appears to be strongly negative.Comment: 9 pages, 9 figures, 1 table, revtex revised version, slightly extende

Ordered phase in the two-dimensional randomly coupled ferromagnet

True ground states are evaluated for a 2d Ising model with random near neighbor interactions and ferromagnetic second neighbor interactions (the Randomly Coupled Ferromagnet). The spin glass stiffness exponent is positive when the absolute value of the random interaction is weaker than the ferromagnetic interaction. This result demonstrates that in this parameter domain the spin glass like ordering temperature is non-zero for these systems, in strong contrast to the 2d Edwards-Anderson spin glass.Comment: 7 pages; 9 figures; revtex; new version much extende

Low-energy excitations in the three-dimensional random-field Ising model

The random-field Ising model (RFIM), one of the basic models for quenched disorder, can be studied numerically with the help of efficient ground-state algorithms. In this study, we extend these algorithm by various methods in order to analyze low-energy excitations for the three-dimensional RFIM with Gaussian distributed disorder that appear in the form of clusters of connected spins. We analyze several properties of these clusters. Our results support the validity of the droplet-model description for the RFIM.Comment: 10 pages, 9 figure

Ground-state behavior of the 3d +/-J random-bond Ising model

Large numbers of ground states of the three-dimensional $\pm J$ random-bond Ising model are calculated for sizes up to $14^3$ using a combination of a genetic algorithm and Cluster-Exact Approximation. Several quantities are calculated as function of the concentration $p$ of the antiferromagnetic bonds. The critical concentration where the ferromagnetic order disappears is determined using the Binder cumulant of the magnetization. A value of $p_c=0.222\pm 0.005$ is obtained. From the finite-size behavior of the Binder cumulant and the magnetization critical exponents $\nu=1.1 \pm 0.3$ and $\beta=0.2 \pm 0.1$ are calculated.Comment: 8 pages, 11 figures, revte