We analyze models of spin glasses on the two-dimensional square lattice by exploiting symmetry arguments. The replicated partition functions of the Ising and related spin glasses are shown to have many remarkable symmetry properties as functions of the edge Boltzmann factors. It is shown that the applications of homogeneous and Hadamard inverses to the edge Boltzmann matrix indicate reduced complexities when the elements of the matrix satisfy certain conditions, suggesting that the system has special simplicities under such conditions. Using these duality and symmetry arguments we present a conjecture on the exact location of the multicritical point in the phase diagram. Let us start by considering the Hamiltonian of the ±J Ising modelwhere J ij is ferromagnetic J(> 0) with probability p and antiferromagnetic −J with 1 − p. The sum extends over nearest neighbours on the square lattice. The randomness in J ij will be treated by the replica method. We will mainly consider the case of positive integer n, the number of replicas. Some results for the quenched limit n → 0 will be discussed in subsequent sections. The constraints of Ising spins and the ±J distribution of the interactions will be relaxed later in the present section.

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Two patients developed renal mucormycosis following transplantation of kidneys from the same donor, a near-drowning victim in a motor vehicle crash. Genotypically, indistinguishable strains of Apophysomyces elegans were recovered from both recipients. We investigated the source of the infection including review of medical records, environmental sampling at possible locations of contamination and query for additional cases at other centers. Histopathology of the explanted kidneys revealed extensive vascular invasion by aseptate, fungal hyphae with relative sparing of the renal capsules suggesting a vascular route of contamination. Disseminated infection in the donor could not be definitively established. A. elegans was not recovered from the same lots of reagents used for organ recovery or environmental samples and no other organ transplant-related cases were identified. This investigation suggests either isolated contamination of the organs during recovery or undiagnosed disseminated donor infection following a near-drowning event. Although no changes to current organ recovery or transplant procedures are recommended, public health officials and transplant physicians should consider the possibility of mucormycosis transmitted via organs in the future, particularly for near-drowning events. Attention to aseptic technique during organ recovery and processing is re-emphasized.

International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes have been proposed as a method of public health surveillance and are widely used in public health and clinical research. However, ICD-9-CM codes have been found to have variable accuracy for both health-care billing and disease classification, and they have never been comprehensively validated for use in public health surveillance. Therefore, the authors undertook a comprehensive analysis of the positive predictive values (PPVs) of ICD-9-CM codes for communicable diseases in 6 North Carolina health-care systems for the year 2003. Stratified random samples of patient charts with ICD-9-CM diagnoses for communicable diseases were reviewed and evaluated for their concordance with the Centers for Disease Control and Prevention surveillance case definitions. Semi-Bayesian hierarchical regression techniques were employed on the ensemble of disease-specific PPVs in order to reduce the overall mean squared error. The authors found that for the majority for diseases with higher incidence and straightforward laboratory-based diagnoses, the PPVs were high (>80%), with the important exception of tuberculosis, which had a PPV of 28.6% (95% uncertainty interval: 15.6, 46.5).

Reporting proportions were <50% for 49 of the 53 diseases evaluated.