Search for standard model production of four top quarks in the lepton + jets channel in pp collisions at √s = 8 TeV

Open Access, Copyright CERN, for the benefit of the CMS Collaboration. Article funded by SCOAP3.Abstract: A search is presented for standard model (SM) production of four top quarks (Formula presented.) in pp collisions in the lepton + jets channel. The data correspond to an integrated luminosity of 19.6 fb−1 recorded at a centre-of-mass energy of 8 TeV with the CMS detector at the CERN LHC. The expected cross section for SM (Formula presented.) production is (Formula presented.). A combination of kinematic reconstruction and multivariate techniques is used to distinguish between the small signal and large background. The data are consistent with expectations of the SM, and an upper limit of 32 fb is set at a 95% confidence level on the cross section for producing four top quarks in the SM, where a limit of 32 ± 17 fb is expected

Ependimomas: achados clínicos, epidemiológicos e anatomopatológicos de 22 casos Ependymonas: clinical, epidemiological and pathological findings of 22 cases

Ependimomas são neoplasias compostas por células ependimárias neoplásicas, manifestando-se predominantemente em crianças e adultos jovens. Relatamos os achados clínicos, epidemiológicos e anatomopatológicos de 22 casos de ependimomas. Dos 22 casos analisados, 14 ocorreram em pacientes do sexo masculino e 8 em pacientes femininos. As idades variaram de 1 a 58 anos, com média de 24,63 anos. Quanto à localização, 10 casos acometeram medula, 7 ocorreram em hemisférios cerebrais, 2 intraventriculares e 1 no tronco cerebral. Os sinais e sintomas observados incluiram redução da força muscular (59,1% dos pacientes), alterações da marcha (36,3%), alterações da sensibilidade(36,3%), hiperreflexia e sindrome de hipertensão endocraniana, com período de evolução variando de 15 dias a 8 anos, com média de 17,58 meses. Sete pacientes foram submetidos a ressecção cirúrgica total , 7 a exérese parcial, 4 a exérese parcial associada a radioterapia adjuvante, 3 a ressecção parcial seguida de quimioterapia e 1 a tumorectomia total associada a radioterapia. Evidenciou-se taxa de recidiva tumoral total de 18,2%. Estes achados aproximam-se dos encontrados na literatura internacional, corroborando para a compreensão do comportamento biológico deste tumor.<br>Ependymomas are composed of neoplastic ependymal cells, affecting mainly children and young adults. We report the clinical and pathological findings of 22 cases of ependymomas. Fourteen patients were males and 8 were females. The ages ranged between 1 and 58 years, with a mean of 24.63 years. The symptoms reflected the growth and topography of the tumours; muscle weakness (59.1%), gait disorders (36.3%), sensitive disorders (36.3%), hyperreflexia and intracranial hypertension syndrome were the most frequent symptoms. Ten tumours affected the medulla, 7 the cerebral hemispheres, 2 the cerebral ventricles and 1 brain stem. Seven patients were submitted total resection of the tumor, from which one received adjuvant radiotherapy. 15 other patients were submitted to partial resection; from which 4 received adjuvant radiotherapy, 3 adjuvant chemotherapy and 1 chemotherapy and radiotherapy. The recurrence rate was 18.2%. These results are similar with the literature and may contribute to further understanding the biological behavior of these tumours