Wilson Loops and Area-Preserving Diffeomorphisms in Twisted Noncommutative Gauge Theory

We use twist deformation techniques to analyse the behaviour under area-preserving diffeomorphisms of quantum averages of Wilson loops in Yang-Mills theory on the noncommutative plane. We find that while the classical gauge theory is manifestly twist covariant, the holonomy operators break the quantum implementation of the twisted symmetry in the usual formal definition of the twisted quantum field theory. These results are deduced by analysing general criteria which guarantee twist invariance of noncommutative quantum field theories. From this a number of general results are also obtained, such as the twisted symplectic invariance of noncommutative scalar quantum field theories with polynomial interactions and the existence of a large class of holonomy operators with both twisted gauge covariance and twisted symplectic invariance.Comment: 23 page

A new U–Pb zircon age for an ash layer at the Bathonian–Callovian boundary, Argentina

A U–Pb zircon age of 164.64^0.2 Ma (95% confidence level) is reported for an ash bed, at the Bathonian–Callovian (late Middle Jurassic) boundary, determined by isotope dilution thermal ionisation mass spectrometry from individual, chemically abraded grains. The volcanic ash layer occurs within the Chacay Melehue Formation, Chacay Melehue section, Neuque´n Province, central west Argentina, above the last record of ammonites of the regional Lilloettia steinmanni Standard Zone, and, stratigraphically, where the first of those of the regional Eurycephalites vergarensis Standard Zone appears, generally referred to as the uppermost Bathonian and the lowermost Callovian, respectively. This ash layer represents the only known datable horizon worldwide that is directly related to a well-documented ammonite faunal succession at this boundary. The U–Pb zircon age is older than one previously reported for the same bed and closer to an estimation of 164.7^4Ma for the boundary based on the scaling durations of ammonite zones to their subzones in the sub-boreal standard zonation. The new age agrees better with the age model for the Oxfordian through Bathonian M-sequence magnetic anomalies in the Pacific and contributes to the radioisotopic age calibration of the Jurassic time scale.Facultad de Ciencias Naturales y Muse

Past and Present Forest Composition and Natural History of Deep Woods, Hocking County, Ohio

Author Institution: Department of Environmental and Plant Biology, Ohio UniversityDeep Woods, a 114-ha private preserve in Hocking County, OH, is the site of an all taxa biotic inventory (ATBI) coordinated by the Ohio Biological Survey. Here we describe the forest vegetation and natural history of the site and evaluate the role of human disturbance in structuring the regional landscape. Due to various abiotic factors, the area offers a diversity of habitats and species. The bedrock geology consists of sedimentary rock from the Mississippian and Pennsylvanian formations with alluvial deposits along a riparian corridor. At least three soil orders are represented: alfisols, inceptisols, and ultisols. As is typical of most of unglaciated Ohio, the forests here have been subjected to a long history of anthropogenic disturbance. The first inhabitants of the area were ancient moundbuilders (ca. 2500 YBP). During the 1700s, Shawnee and Delaware groups resided throughout the county. Anglo settlers drove all Native American groups out of the area by the early 1800s. The original land survey data (1801) suggested that the dominant vegetation at Deep Woods was composed of Quercus alba, Q. velutina, Carya spp., and Cornus florida (relative importance value, RIV = 34, 13, 12, 11%, respectively). Tax records show that Anglo-ownership of the property dates from the mid-1830s. County death records indicate occupations of 19th century landowners primarily as farmers. Dominant vegetation types include: hydric floodplain, mesic upland, and xeric ridgetop. Betula nigra, Carpinus caroliniana, Ulmus americana, andLiriodendron tulipifera (RIV = 16, 11, 11, 10%) dominate the floodplain. Whereas L. tulipifera, Acer saccharum, andB. alleghaniensis (RIV = 21, 15, 11%) and A rubrum, Q. prinus, and Q. alba (RIV= 27, 13, 9%) dominate the upland and ridgetop, respectively. Several other minor habitats also exist such as pasture fields, hemlock ravines, sandstone outcrops, and rockhouse formations. We conclude that the present species composition resembles the 1801 land survey, even though the post settlement disturbances were different than Native American disturbance regimes

Intrahepatic persistent fetal right umbilical vein: a retrospective study

Introduction: To appraise the incidence and value of intrahepatic persistent right umbilical vein (PRUV). Methods: This was a single-center study. Records of all women with a prenatal diagnosis of intrahepatic PRUV were reviewed. The inclusion criteria were women with gestational age greater than 13 weeks of gestation. Exclusion criteria were fetuses with situs abnormalities, due to the hepatic venous ambiguity, and extrahepatic PRUV. The primary outcome was the incidence of intrahepatic PRUV in our cohort. The secondary outcomes were associated malformations. Results: 219/57,079 cases (0.38%) of intrahepatic PRUV were recorded. The mean gestational age at diagnosis was 21.8 ± 2.9 weeks of gestations. PRUV was isolated in the 76.7%, while in 23.3% was associated with other major or minor abnormalities. The most common associated abnormalities were cardiovascular abnormalities (8.7%), followed by genitourinary abnormalities (6.4%), skeletal abnormalities (4.6%), and central nervous system abnormalities (4.1%). Within the cardiovascular abnormalities, the most common one was ventricular septal defect (six cases). Conclusion: In most cases PRUV is an isolated finding. Associated minor or major malformations are presented in the 23.3% of the cases, so this finding should prompt detailed prenatal assessment of the fetus, with particular regard to cardiovascular system

Metal determination in organic fluids of patients with stainless steel hip arthroplasty.

In 20 stainless steel Charnley hip arthroplasties (with a follow-up of 10-13 years) nickel, chromium and manganese levels were measured in blood, plasma and urine by atomic absorption spectrophotometry. Skin patch tests for these metals, and clinical and roentgenographic results of arthroplasty were also assessed. Metal levels in organic fluids were plotted against a control population homogene- ous for age, residence and anamnestic conditions with the first, but which had never undergone a prosthesis or other metallic implant surgical procedure. Nickel levels in blood, plasma and urine, manganese levels in blood and urine and chromium levels in plasma were significantly higher in the hip prostheses popula- tion. Metal ion release from stainless steel prostheses is discussed with regard to implant failure, metal sensitivity and carcinogenesis

Etiological diagnosis, prognostic significance and role of electrophysiological study in patients with Brugada ECG and syncope.

BACKGROUND: Syncope is considered a risk factor for life-threatening arrhythmias in Brugada patients. Distinguishing a benign syncope from one due to ventricular arrhythmias is often difficult, unless an ECG is recorded during the episode. Aim of the study was to analyze the characteristics of syncopal episodes in a large population of Brugada patients and evaluate the role of electrophysiological study (EPS) and the prognosis in the different subgroups. METHODS AND RESULTS: One hundred ninety-five Brugada patients with history of syncope were considered. Syncope were classified as neurally mediated (group 1, 61%) or unexplained (group 2, 39%) on the basis of personal and family history, clinical features, triggers, situations, associated signs, concomitant therapy. Most patients underwent EPS; they received ICD or implantable loop-recorder on the basis of the result of investigations and physician's judgment. At 62±45months of mean follow-up, group 1 showed a significantly lower incidence of arrhythmic events (2%) as compared to group 2 (9%, p<0.001). Group 2 patients with positive EPS showed the highest risk of arrhythmic events (27%). No ventricular events occurred in subjects with negative EPS. CONCLUSION: Etiological definition of syncope in Brugada patients is important, as it allows identifying two groups with different outcome. Patients with unexplained syncope and ventricular fibrillation induced at EPS have the highest risk of arrhythmic events. Patients presenting with neurally mediated syncope showed a prognosis similar to that of the asymptomatic and the role of EPS in this group is unproven

I-21 Current therapeutic guidelines in Duchenne Muscular Dystrophy to prolong life

Duchenne's myopathy is an X-linked disease with well defined evolutionary phases, characterized by degradation of the walking function, development of evolutive scoliosis and progressive decline of the respiratory function leading patients to premature death. In 1985 Y. Rideau in France carried out a new global therapeutic strategy for treatment of lower limb deformities, scoliosis deformity and progressive restrictive syndrome. The indication for surgery at the lower limbs is made very early, at the onset of the first signs of disease. The procedures are carried out at the same time and always bilaterally; they include: (i) hip section of superficial flexors; (ii) iliotibial band resection; (iii) subcutaneous tenotomy of semitendineous and gracilis; (iv) subcutaneous lengthening of Achilles tendons. In the post-operative period, the patient begins exercises of active and passive mobility in few days and after three weeks recovers his performances; ambulation will remain almost normal for several years. A comparison of two groups of patients, the first precociously operated on the lower limbs, the other one not operated, shows better performances in the operated group. The indications for surgical treatment of Duchenne scoliosis must be made after the loss of ambulation and not too late, to avoid the concurrent respiratory restrictive syndrome makes the patient inoperable. Over ten years ago, in Poitiers, a specific instrumentation for Duchenne scoliosis was created, providing for cylindrical rods fixed by peduncular screws at the sacro-lumbar level. On the dorso-lumbar level, the rod becomes flat to allow more flexibility of the trunk. The complications observed in a group of 55 patients operated for scoliosis, consisted in 2 cases of breaking of rods and 1 superficial infection. The surgery approach in DMD has the double aim to prolong the time of the autonomous ambulation and to avoid the evolution of scoliosis, limiting the harmful effects of the scoliosis on the respiratory function. However, the surgery alone is unable to prolong the life expectancy in these patients, without treating the restrictive respiratory syndrome, first by nasal ventilation and then by elective tracheotomy, essential for the survival of the patient