Gravitating discs around black holes

Fluid discs and tori around black holes are discussed within different approaches and with the emphasis on the role of disc gravity. First reviewed are the prospects of investigating the gravitational field of a black hole--disc system by analytical solutions of stationary, axially symmetric Einstein's equations. Then, more detailed considerations are focused to middle and outer parts of extended disc-like configurations where relativistic effects are small and the Newtonian description is adequate. Within general relativity, only a static case has been analysed in detail. Results are often very inspiring, however, simplifying assumptions must be imposed: ad hoc profiles of the disc density are commonly assumed and the effects of frame-dragging and completely lacking. Astrophysical discs (e.g. accretion discs in active galactic nuclei) typically extend far beyond the relativistic domain and are fairly diluted. However, self-gravity is still essential for their structure and evolution, as well as for their radiation emission and the impact on the environment around. For example, a nuclear star cluster in a galactic centre may bear various imprints of mutual star--disc interactions, which can be recognised in observational properties, such as the relation between the central mass and stellar velocity dispersion.Comment: Accepted for publication in CQG; high-resolution figures will be available from http://www.iop.org/EJ/journal/CQ

Microsecond Isomer at the N=20 Island of Shape Inversion Observed at FRIB

Excited-state spectroscopy from the first Facility for Rare Isotope Beams (FRIB) experiment is reported. A 24(2)-$\mu$s isomer was observed with the FRIB Decay Station initiator (FDSi) through a cascade of 224- and 401-keV $\gamma$ rays in coincidence with $^{32}\textrm{Na}$ nuclei. This is the only known microsecond isomer ($1{\text{ }\mu\text{s}}\leq T_{1/2} < 1\text{ ms}$) in the region. This nucleus is at the heart of the $N=20$ island of shape inversion and is at the crossroads of spherical shell-model, deformed shell-model, and ab initio theories. It can be represented as the coupling of a proton hole and neutron particle to $^{32}\textrm{Mg}$, $^{32}\textrm{Mg}+\pi^{-1} + \nu^{+1}$. This odd-odd coupling and isomer formation provides a sensitive measure of the underlying shape degrees of freedom of $^{32}\textrm{Mg}$, where the onset of spherical-to-deformed shape inversion begins with a low-lying deformed $2^+$ state at 885 keV and a low-lying shape-coexisting $0_2^+$ state at 1058 keV. We suggest two possible explanations for the 625-keV isomer in $^{32}$Na: a $6^-$ spherical shape isomer that decays by $E2$ or a $0^+$ deformed spin isomer that decays by $M2$. The present results and calculations are most consistent with the latter, indicating that the low-lying states are dominated by deformation.Comment: 7 pages, 5 figures, accepted by Physical Review Letter

Hydatid cysts in muscles: clinical manifestations, diagnosis, and management of this atypical presentation

ABSTRACTINTRODUCTION: Hydatid cysts are rarely detected in muscle tissue (0.7-0.9%), even in endemic countries. The aim of this study was to present information regarding the clinical manifestations, diagnosis, and management of muscle echinococcosis.METHODS: Twenty-two patients with hydatid cysts in the muscle were followed from January 2006 through December 2014.RESULTS: Twenty-four sites of muscle involvement were observed in the 22 patients. Fifteen (68%) of our patients were women, while seven (32%) were men. The mean age was 28.1 ± 15.4 (6-61) years. The most frequent locations were the thigh (27.2%) and the paravertebral region (13.6%). Most patients reported a painless slow-growing mass with normal overlying skin. Most (90.2%) cases were treated by surgical excision and fine-needle aspiration.CONCLUSIONS: Primary muscle hydatid cyst should be considered in the differential diagnosis in cystic masses of the muscular system without pain and localized enlargement of soft tissue, especially in endemic areas. Hydatid cyst should be investigated using serological tests and imaging modalities. If possible, total surgical excision of hydatid cyst in the muscle should be performed

Esophageal and Gastric Malignancies After Bariatric Surgery: a Retrospective Global Study

Background: Bariatric surgery can influence the presentation, diagnosis, and management of gastrointestinal cancers. Esophagogastric (EG) malignancies in patients who have had a prior bariatric procedure have not been fully characterized. Objective: To characterize EG malignancies after bariatric procedures. Setting: University Hospital, United Kingdom. Methods: We performed a retrospective, multicenter observational study of patients with EG malignancies after bariatric surgery to characterize this condition. Results: This study includes 170 patients from 75 centers in 25 countries who underwent bariatric procedures between 1985 and 2020. At the time of the bariatric procedure, the mean age was 50.2 ± 10 years, and the mean weight 128.8 ± 28.9 kg. Women composed 57.3% (n = 98) of the population. Most (n = 64) patients underwent a Roux-en-Y gastric bypass (RYGB) followed by adjustable gastric band (AGB; n = 46) and sleeve gastrectomy (SG; n = 43). Time to cancer diagnosis after bariatric surgery was 9.5 ± 7.4 years, and mean weight at diagnosis was 87.4 ± 21.9 kg. The time lag was 5.9 ± 4.1 years after SG compared to 9.4 ± 7.1 years after RYGB and 10.5 ± 5.7 years after AGB. One third of patients presented with metastatic disease. The majority of tumors were adenocarcinoma (82.9%). Approximately 1 in 5 patients underwent palliative treatment from the outset. Time from diagnosis to mortality was under 1 year for most patients who died over the intervening period. Conclusion: The Oesophago-Gastric Malignancies After Obesity/Bariatric Surgery study presents the largest series to date of patients developing EG malignancies after bariatric surgery and attempts to characterize this condition.info:eu-repo/semantics/publishedVersio

Emissão de metano por decomposição de resíduo florestal inundado

A construção de represas pode aumentar a emissão de gases do efeito estufa (GEE), principalmente metano (CH4) pela decomposição anaeróbica dos resíduos florestais, como galhos, ramos, folhas e miscelânea inundados. Objetivou-se, neste estudo, avaliar a emissão de CH4 após a inundação do solo coberto com resíduos florestais. Unidades experimentais foram construídas com tubos de PVC contendo solo e diferentes combinações de dose (0; 21,2; 42,3 e 64,1 Mg ha-1) e tipo de resíduos (folhas, ramos e miscelânea, galhos e composição original) e água de rio. O delineamento experimental foi inteiramente casualizado com arranjo fatorial e três repetições. As taxas de emissão de CH4 foram monitoradas em 19 eventos durante um ano (Fevereiro/2012 a Março/2013). Cerca de 75 dias após a incubação do solo com resíduos florestais verificou-se aumento das emissões de CH4, ocorrendo dois picos de emissão, aos 111 e aos 249 dias. A emissão acumulada de CH4 no primeiro ano de alagamento foi de 200 g C m-2 na dose zero, passando a valores próximos a 400 g C m-2 nas doses de 21,2 Mg ha-1 e maiores, não havendo efeito do tipo de resíduo, apenas da dose, como fator isolado

Serum ferritin level in febrile children with and without seizures

Background: Although febrile seizure is the most common cause of convulsion in childhood and strongly age-dependent, its incidence is rare before 9 months and after 5 years. Moreover, iron deficiency in these ages may have a detrimental effect on neurological and intellectual functioning. This study was designed to determine the serum ferritin level in febrile children with and without seizures. Materials and Methods: This case-control study was performed on 80 children (6 months to 5 years) referred to Kashan Shahid Beheshti hospital from January until June 2010.They were divided into two equal case and control groups (children with febrile seizures and febrile children without seizure, respectively). Children with the CNS disorder, developmental delay, renal failure, and shigellotic gastroenteritis were excluded. Ferritin, Hb, MCV and MCH values between the two groups were compared. Results: The mean serum feritin levels were 97.6±90.6 ng/ml for cases and 109.2±106.2 ng/ml for controls (P=0.351).The mean corpuscular hemoglobin was 11.17±0.881 g/dl in the case group and 11.04±0.963 g/dl in the control one (P=0.534). Moreover, the mean MCV in the febrile seizure and fever groups were 73.71±4.16 fl and 71.86±4.42 fl, respectively (P=0.049). Also, the mean MCH in the febrile seizure and fever groups were 24.80±1.64 pg and 23.83±2.16 pg, respectively (P=0.033). Conclusion: No relationship between the serum ferritin level and febrile seizure is seen in both groups