Practice Makes Perfect: The Volume-Outcome Association in Pediatric Stoma Closure Surgery

Children with anorectal malformations often receive a temporary colostomy or ileostomy before surgical repair of the anomaly to divert stool and allow their anatomy time to heal. Once their bodies have healed, the stoma is taken down, a standard procedure for pediatric general surgeons. However, for decades, stoma takedown surgery has been associated with a high risk of postoperative complications. This study seeks to determine if hospital prior-year stoma closure case volume influences pediatric patients\u27 quality outcome measures. Population. This study identified 340 pediatric patients having undergone stoma closure surgery during the study period at hospitals in a representative sample of seven states; Arkansas, Florida, Georgia, Maryland, Mississippi, New York, and Washington. Study Design. This study is a retrospective analysis of archival billing data for pediatric stoma closure patients. The billing data source is the 2016 - 2017 Agency for Healthcare Research and Quality\u27s (AHRQ) Healthcare Cost and Utilization Project (HCUP) database. Outcome Measures. This study uses generally accepted surrogate measures of a quality outcome. The quality outcome measures for this study are the rate of in-hospital mortality during the index admission, readmission to the hospital within 30 days of discharge, and length of stay (LOS) during the index admission. Results. One mortality occurred in the study population (.29%), while 39 patients were readmitted (11.5%). Logistic regression analysis found no significant volume-outcome association between volume and the outcome measures. However, when categorized into age groups, a statistically significant association exists between hospital prior-year volume and readmission (p \u3c .04) in the infant age group (Age \u3c 1). A similar association was found between hospital prior-year volume and LOS (p \u3c .002) in the infant group compared to the non-infant group. With each prior-year increase of 10 cases, the likelihood of readmission decreases by 52% and expected hospitalization days decreases by 25%. Conclusion. This study validates an inverse hospital volume-readmission association in infant stoma closure surgery and an inverse volume-LOS association among all pediatric patients, with the magnitude of the association being most significant in the infant population

Rejuvenation in the Random Energy Model

We show that the Random Energy Model has interesting rejuvenation properties in its frozen phase. Different `susceptibilities' to temperature changes, for the free-energy and for other (`magnetic') observables, can be computed exactly. These susceptibilities diverge at the transition temperature, as (1-T/T_c)^-3 for the free-energy.Comment: 9 pages, 1 eps figur

Symmetrical Temperature-Chaos Effect with Positive and Negative Temperature Shifts in a Spin Glass

The aging in a Heisenberg-like spin glass Ag(11 at% Mn) is investigated by measurements of the zero field cooled magnetic relaxation at a constant temperature after small temperature shifts $|\Delta T/T_g| < 0.012$. A crossover from fully accumulative to non-accumulative aging is observed, and by converting time scales to length scales using the logarithmic growth law of the droplet model, we find a quantitative evidence that positive and negative temperature shifts cause an equivalent restart of aging (rejuvenation) in terms of dynamical length scales. This result supports the existence of a unique overlap length between a pair of equilibrium states in the spin glass system.Comment: 4 page

Anomalous Hall Effect in three ferromagnets: EuFe4Sb12, Yb14MnSb11, and Eu8Ga16Ge30

The Hall resistivity (Rho_xy), resistivity (Rho_xx), and magnetization of three metallic ferromagnets are investigated as a function of magnetic field and temperature. The three ferromagnets, EuFe4Sb12 (Tc = 84 K), Yb14MnSb11 (Tc = 53 K), and Eu8Ga16Ge30 (Tc = 36 K) are Zintl compounds with carrier concentrations between 1 x 10^21 cm^-3 and 3.5 x 10^21 cm^-3. The relative decrease in Rho_xx below Tc [Rho_xx(Tc)/Rho_xx(2 K)] is 28, 6.5, and 1.3 for EuFe4Sb12, Yb14MnSb11, and Eu8Ga16Ge30 respectively. The low carrier concentrations coupled with low magnetic anisotropies allow a relatively clean separation between the anomalous (Rho_'xy), and normal contributions to the measured Hall resistivity. For each compound the anomalous contribution in the zero field limit is fit to alpha Rho_xx + sigma_xy rho_xx^2 for temperatures T < Tc. The anomalous Hall conductivity, sigma_xy, is -220 +- 5 (Ohm^-1 cm^-1), -14.7 +- 1 (Ohm^-1 cm^-1), and 28 +- 3 (Ohm^-1 cm^-1) for EuFe4Sb12, Yb14MnSb11, and Eu8Ga16Ge30 respectively and is independent of temperature for T < Tc if the change in spontaneous magnetization (order parameter) with temperature is taken into account. These data are consistent with recent theories of the anomalous Hall effect that suggest that even for stochiometric ferromagnetic crystals, such as those studied in this article, the intrinsic Hall conductivity is finite at T = 0, and is a ground state property that can be calculated from the electronic structure.Comment: 22 pages, 13 figures Submitted to PR

Role of omega-3 polyunsaturated fatty acids in diet of patients with rheumatic diseases

The beneficial effects of ω-3 polyunsaturated fatty acids have been widely described in the literature in particular those on cardiovascular system. In the last decade there has been an increased interest in the role of these nutrients in the reduction of articular inflammation as well as in the improvement of clinical symptoms in subjects affected by rheumatic diseases, in particular rheumatoid arthritis (RA). Nutritional supplementation with ω-3 may represent an additional therapy to the traditional pharmacological treatment due to the anti-inflammatory properties which characterize this class of lipids: production of alternative eicosanoids, reduction of inflammatory cytochines, reduction of T-lymphocytes activation, reduction of catabolic enzymes activity. The encouraging results of dietetic therapy based on ω- 3 in RA are leading researchers to test their effectiveness on patients with other rheumatic conditions such as systemic lupus erythematosus and ankylosing spondylitis. Nutritional therapy based on food rich in ω-3 or on supplementation with fish oil capsules, proved to be a valid support to he treatment of chronic inflammatory rheumatic diseases