The ϵ\epsilon-ζ\zeta Transition in Solid Oxygen

The structure of solid oxygen has been studied at pressures from 50 to 140~GPa using static structure search methods and molecular dynamics simulations with density functional theory and a hybrid exchange functional. Several crystalline structures with space group symmetries {\it Pnma}, {\it P}\,2$_{1}${\it /m}, {\it Pm} and {\it P}\,6$_3$/{\it mmc} have been identified as candidates for the $\zeta$ phase of oxygen at 0~K. Within the hybrid exchange functional framework and at 300~K temperature, {\it Pm} is shown to be energetically most favorable above 111~GPa. A comparison with experimental X-ray diffraction, spectroscopic and superconductivity measurements is provided for all competing structures.Comment: 6 pages, 5 figure

Congenital anomalies in low- and middle-income countries: the unborn child of global surgery.

Surgically correctable congenital anomalies cause a substantial burden of global morbidity and mortality. These anomalies disproportionately affect children in low- and middle-income countries (LMICs) due to sociocultural, economic, and structural factors that limit the accessibility and quality of pediatric surgery. While data from LMICs are sparse, available evidence suggests that the true human and financial cost of congenital anomalies is grossly underestimated and that pediatric surgery is a cost-effective intervention with the potential to avert significant premature mortality and lifelong disability

Pattern analysis of Chalcolithic settlements in the valley of Sarfirouzabad, Kermanshah, Iran

The advent of new technologies has had a profound impact on the evolution of archaeological methodological approaches, allowing archaeologists to refine traditional assessments about the nature of past human societies and to expand their theoretical horizons. GIS-based technologies are among the new technologies aimed at reconstructing spatial-related aspects of past human communities. The paper illustrates the use of some ArcGIS tools supplemented with satellite low resolution images to produce a layered workable archaeological map suitable for analyzing specific issues such as ancient cultural ecology and landscape reconstruction. Integrated satellite imagery and GIS analyses are applied to reconstruct spatial distribution patterns of the Chalcolithic period in Central Zagros as seen from the Sarfirouzabad valley adjacent to Mahidasht inter-mountainous plain, near Kermanshah, Iran. The search for considerable changes in the settlement distribution patterns relating to the ecological attributes is one of the aims of the paper, using GIS-based methods such as Thiessen polygons analysis, site-point spatial distribution analysis and buffer analysis. The results are discussed through categories covering distribution of Chalcolithic sites over the different environs of the study area, spatial distribution of pottery styles, and spatial models of Chalcolithic distribution patterns

Esophageal atresia: comparison between survivors and mortality cases who underwent surgery over a 2-year period in two referral hospitals, Tehran, Iran

Introduction and aim The aim of this study was to compare the type of suture, technique of suture, and technique of anastomosis between survivors and mortality cases.Patients and methods This study was conducted in Bahrami Hospital and Children’s Medical Center on cases with esophageal atresia who underwent surgery for esophageal atresia and/or tracheoesophageal fistula repair. The places of study were Bahrami Hospital and Children’s Medical Center, two referral centers for pediatric surgery in Tehran. The duration of the study was 2 years, starting from April 1999. Survivors and mortality cases were compared with regard to sex, type of surgery, suture material, and technique of anastomosis. Gross classification was used for typing of anomaly. All data were analyzed again using SPSS ver. 13.0 and Epi-info ver. 6.04d (CDC,WHO). The v2-test was used for comparison.Results In this study, 21 (male = 9, female =12) mortality cases and 53 (male = 29, female =24) survivors were included. Among them, 18 (85.7%) mortality cases and 51 (96.2%) survivors had type C atresia (P = 0.23). Thoracotomy and repair of atresia was performed in 10 (47.6%) mortality cases and 51 (96.2%) survivors. Gastrostomy and tracheoesophageal fistula repair was performed in eight (38.1%) mortality cases. Gastrostomy and cervical esophagostomy was performed in three (14.7%) mortality cases and two (3.8%) survivors. Anastomotic leak was noted in eight mortality cases and 10 survivors who underwent thoracotomy and atresia repair (P = 0.0005). End-to-end anastomosis was performed for nine mortality cases and 45 survivors (P = 0.7). Extrapleural thoracotomy was performed in nine mortality cases and 45 survivors (P = 0.7). Single-layer anastomosis was performed in eight mortality cases and 36 survivors (P = 0.82). There were no significant differences between survivors and mortality cases with regard to sex and type of atresia (P =0.23). Thoracotomy and atresia repair was more frequently performed in survivors than in mortality cases (P = 0.000004). Anastomotic leakage was significantly higher in mortality cases compared with survivors (P = 0.0005).Conclusion Anastomosis leakage was associated with higher mortality. The rate of thoracotomy and atresia repair surgery is higher in survivors compared with mortality cases. Keywords: esophageal atresia, risk factors, surgical repai