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Sample records for massive haemoptysis due

  1. Aspergilloma and massive haemoptysis

    PubMed Central

    Ding, Wern Yew; Chan, Tze; Yadavilli, Rajesh Kumar; McWilliams, Richard

    2014-01-01

    A 40-year-old homeless woman who was a known intravenous drug user and heroin smoker, presented with massive haemoptysis. Initial CT-pulmonary angiogram (CT-PA) did not show active haemorrhage but found an opacity in a right upper lobe cavity likely to represent a mycetoma. She was started on antifungal therapy but haemoptysis persisted and bronchial angiography was performed. Again no active haemorrhage was identified but abnormal vasculature was seen supplying the right upper lobe. This was empirically embolised with particles which did not improve her symptoms. A subsequent CT-PA identified a pulmonary artery pseudoaneurysm in the cavity wall which was successfully embolised. There was no further haemoptysis and a repeat CT-PA 3 weeks later showed continuing occlusion of the pulmonary artery aneurysm. Investigations for tuberculosis were negative and she was discharged clinically well and on long-term antifungal therapy. PMID:24739651

  2. Embolisation of a Bronchial Artery of Anomalous Origin in Massive Haemoptysis

    PubMed Central

    Md Ralib, Ahmad Razali; Han, Ng Teck; Hin, How Soon; Muda, Ahmad Sobri

    2010-01-01

    Massive haemoptysis is the most dreaded of all respiratory emergencies. Bronchial artery embolisation is known to be a safe and effective procedure in massive haemoptysis. Bronchial artery of anomalous origin presents a diagnostic challenge to interventional radiologists searching for the source of haemorrhage. Here, we report a case of massive haemoptysis secondary to a lung carcinoma with the bronchial artery originating directly from the right subclavian artery. This artery was not evident during the initial flush thoracic aortogram. The anomalous-origin bronchial artery was then embolised using 15% diluted glue with good results. An anomalous-origin bronchial artery should be suspected if the source of haemorrhage is not visualised in the normally expected bronchial artery location. PMID:22135550

  3. Intermittent Haemoptysis due to an Aortobronchial Fistula in a Warmblood Mare.

    PubMed

    Versnaeyen, H; Saey, V; Vermeiren, D; Chiers, K; Ducatelle, R

    2016-01-01

    A 7-year-old warmblood mare showed sudden onset of mild intermittent haemoptysis. Clinical examination revealed no significant abnormalities. Haematological examination showed mild anaemia, hypoalbuminaemia and neutrophilia. Coagulation tests were normal. Endoscopic examination revealed unilateral pulmonary haemorrhage with blood clots in the bronchi and trachea. Treatment with antibiotics was started and the horse was given stable rest. Two weeks later, the horse was found dead with blood and frothy sputum leaking from the nostrils. Post-mortem examination revealed a large thoracic aortic aneurysm communicating with a pseudoaneurysm that had formed a fistula into a right bronchial branch. Microscopical examination of the aneurysm showed extensive medial fibrosis with prominent degeneration, fragmentation and mineralization of the elastic fibres and deposition of mucoid material in the tunica media. The pseudoaneurysm was lined by collagen bundles admixed with fibroblasts and a small amount of adipose tissue. Aortobronchial fistula is a rare condition in man that is usually associated with primary aortic pathology, most often aneurysms. To the authors' knowledge this is the first case of a fatal aortobronchial fistula in a horse or any other animal species. PMID:27535296

  4. A simplified approach to haemoptysis.

    PubMed

    Ong, Zi Yang Trevor; Chai, Hui Zhong; How, Choon How; Koh, Jansen; Low, Teck Boon

    2016-08-01

    Haemoptysis is commonly seen in the healthcare setting. It can lead to life-threatening complications and therefore requires careful evaluation of the severity and status of the patient. Common causes of haemoptysis can be broadly grouped into five main categories: infective, neoplastic, vascular, autoimmune and drug-related. Detailed history-taking and careful physical examination are necessary to provide a diagnosis and assess the patient's haemodynamic status. Physicians must have a clear understanding of the criteria for further investigations and the need for a specialist or inpatient referral for management. PMID:27549136

  5. Thoracic Endometriosis-A Rare Cause of Haemoptysis

    PubMed Central

    Alwadhi, Seema; Chaudhary, Bhupendra; Gehlot, Kirti

    2016-01-01

    Thoracic endometriosis is a rare condition and occurs in females of reproductive age due to the presence of active endometrial tissue in tracheobronchial tree, lung parenchyma and lung pleura. A typical history of haemoptysis during menstrual periods and strong suspicion of the disease entity is important for the diagnosis and management of the case. Diagnosis of the disease is usually delayed. Serial CT thorax during menstrual period and in non-menstrual period supports the diagnosis. We present here a case of catamenial haemoptysis. The diagnosis was missed initially but later a detailed clinical history revealed the same. Serial computed tomography of thorax taken during menstrual and after menstrual period supported the diagnosis. Though bronchoscopy was able to reveal hyperemic tissue in the tracheobronchial tree, bronchial washing was inconclusive. The patient was treated successfully with danazol. PMID:27190915

  6. Lung abscess: a neglected cause of life threatening haemoptysis.

    PubMed Central

    Philpott, N J; Woodhead, M A; Wilson, A G; Millard, F J

    1993-01-01

    Three cases who presented with life threatening haemoptysis are reported, all of whom required surgery to control the bleeding. In all three patients chronic lung abscess was responsible for the haemoptysis. Even in the absence of typical clinical or radiographic features of an abscess this diagnosis should be considered in any patient presenting with life threatening haemoptysis. Images PMID:8346503

  7. Haemoptysis after breath-hold diving.

    PubMed

    Boussuges, A; Pinet, C; Thomas, P; Bergmann, E; Sainty, J M; Vervloet, D

    1999-03-01

    Pulmonary oedema has been described in swimmers and self-contained underwater breathing apparatus (Scuba) divers. This study reports three cases of haemoptysis secondary to alveolar haemorrhage in breath-hold divers. Contributory factors, such as haemodynamic modifications secondary to immersion, cold exposure, exercise and exposure to an increase in ambient pressure, could explain this type of accident. Furthermore, these divers had taken aspirin, which may have aggravated the bleeding. PMID:10232449

  8. Fatal haemoptysis in a case of lymphomatoid granulomatosis treated with rituximab.

    PubMed

    Jaffre, S; Jardin, F; Dominique, S; Duet, E; Hubscher, Ph; Genevois, A; Corne, F; Bota, S; Nouvet, G; Thiberville, L

    2006-03-01

    Lymphomatoid granulomatosis is a rare angiocentric and angiodestructive disease, which commonly involves the lungs but also the brain, kidneys, liver and skin. This report describes the case of a 33-yr-old female with an aggressive form of lymphoid granulomatosis treated with an anti-CD20 antibody. Dramatic radiological improvement was seen at the fourth week. However, the patient died at home 1 month after the last rituximab administration from a massive haemoptysis. PMID:16507866

  9. [Massive intravascular hemolysis secondary to sepsis due to Clostridium perfringens].

    PubMed

    Pita Zapata, E; Sarmiento Penide, A; Bautista Guillén, A; González Cabano, M; Agulla Budiño, J A; Camba Rodríguez, M A

    2010-05-01

    Massive hemolysis secondary to sepsis caused by Clostridium perfringens is a rare entity but appears fairly often in the literature. In nearly all published reports, the clinical course is rapid and fatal. We describe the case of a 75-year-old woman with diabetes who was admitted with symptoms consistent with acute cholecystitis. Deteriorating hemodynamics and laboratory findings were consistent with intravascular hemolysis, coagulation disorder, and renal failure. Gram-positive bacilli of the Clostridium species were detected in blood along with worsening indicators of hemolysis. In spite of antibiotic and surgical treatment, hemodynamic support and infusion of blood products, the patient continued to decline and died in the postoperative recovery unit 14 hours after admission. Mortality ranges from 70% to 100% in sepsis due to Clostridium perfringens, and risk of death is greater if massive hemolysis is present, as in the case we report. Only a high degree of clinical suspicion leading to early diagnosis and treatment can improve the prognosis. This bacterium should therefore be considered whenever severe sepsis and hemolysis coincide. PMID:20527348

  10. Fatal Haemoptysis Associated with Dramatic Response to Crizotinib in an ALK-Rearranged Lung Adenocarcinoma.

    PubMed

    Mussat, Elodie; Giraud, Violaine; Julie, Catherine; Chinet, Thierry; Leprieur, Etienne Giroux

    2016-03-01

    The presence of an ALK (Anaplastic Lymphoma Kinase) rearrangement is a rare molecular feature in Non-Small Cell Lung Carcinoma (NSCLC), and concerns mainly non- or light smokers, young patients, with adenocarcinoma histological type. These tumours are particularly sensitive to Alk-targeted therapies, as crizotinib. Crizotinib is usually well-tolerated. We report a case of fatal haemoptysis associated with dramatic response to crizotinib in a patient with an ALK-rearranged lung adenocarcinoma. The patient presented a mediastinal invasion with tracheal involvement and compression of the right pulmonary artery. The initial evolution under crizotinib was good with tumour response. At 6 weeks of crizotinib the patient presented a massive haemoptysis with a tracheobronchial fistula and pneumomediastinum. She died of acute respiratory failure. Our case is the first to report a fatal effect of crizotinib associated with tumour necrosis and good tumour response on a massive mediastinal infiltration. Precautions are recommended with the use of crizotinib in proximal lung tumours with vascular invasion. PMID:27134984

  11. Fatal Haemoptysis Associated with Dramatic Response to Crizotinib in an ALK-Rearranged Lung Adenocarcinoma

    PubMed Central

    Mussat, Elodie; Giraud, Violaine; Julie, Catherine; Chinet, Thierry

    2016-01-01

    The presence of an ALK (Anaplastic Lymphoma Kinase) rearrangement is a rare molecular feature in Non-Small Cell Lung Carcinoma (NSCLC), and concerns mainly non- or light smokers, young patients, with adenocarcinoma histological type. These tumours are particularly sensitive to Alk-targeted therapies, as crizotinib. Crizotinib is usually well-tolerated. We report a case of fatal haemoptysis associated with dramatic response to crizotinib in a patient with an ALK-rearranged lung adenocarcinoma. The patient presented a mediastinal invasion with tracheal involvement and compression of the right pulmonary artery. The initial evolution under crizotinib was good with tumour response. At 6 weeks of crizotinib the patient presented a massive haemoptysis with a tracheobronchial fistula and pneumomediastinum. She died of acute respiratory failure. Our case is the first to report a fatal effect of crizotinib associated with tumour necrosis and good tumour response on a massive mediastinal infiltration. Precautions are recommended with the use of crizotinib in proximal lung tumours with vascular invasion. PMID:27134984

  12. Bronchoscopy as a supplement to computed tomography in patients with haemoptysis may be unnecessary

    PubMed Central

    Nielsen, Klaus; Gottlieb, Magnus; Colella, Sara; Saghir, Zaigham; Larsen, Klaus R.; Clementsen, Paul F.

    2016-01-01

    Background Haemoptysis is a common symptom and can be an early sign of lung cancer. Careful investigation of patients with haemoptysis may lead to early diagnosis. The strategy for investigation of these patients, however, is still being debated. Objectives We studied whether the combination of computed tomography (CT) and bronchoscopy had a higher sensitivity for malignant and non-malignant causes of haemoptysis than CT alone. Methods The study was a retrospective, non-randomised, two-centre study and included patients who were referred from primary care for the investigation of haemoptysis. Results A total of 326 patients were included in the study (mean age 60.5 [SD 15.3] years, 63.3% male). The most common aetiologies of haemoptysis were cryptogenic (52.5%), pneumonia (16.3%), emphysema (8.0%), bronchiectasis (5.8%) and lung cancer (4.0%). In patients diagnosed with lung cancer, bronchoscopy, CT and the combination of bronchoscopy and CT had a sensitivity of 0.61, 0.92 (p<0.05) and 0.97 (p=0.58), respectively. In patients with non-malignant causes of haemoptysis, most aetiologies were diagnosed by CT and comprised mainly pneumonia, emphysema and bronchiectasis. Bronchoscopy did not reveal these conditions and the sensitivity to these conditions was not increased by combining CT and bronchoscopy. Conclusions CT can stand alone as a diagnostic workup for patients with haemoptysis referred to an outpatient clinic. Bronchoscopy does not identify any malignant aetiologies not already diagnosed by CT. Combining the two test modalities does not result in a significant increase in sensitivity for malignant or non-malignant causes of haemoptysis. PMID:27343164

  13. Massive Cerebral Gas Embolism under Discectomy due to Hydrogen Peroxide Irrigation

    PubMed Central

    Zhang, Junjie; Zhang, Chengliang; Yan, Jianqin

    2015-01-01

    Massive cerebral and spinal gas embolism occurs rarely as a complication of discectomy. We report a 54-year-old female who had undergone a discectomy (L3/4 and L4/5) under epidural anesthesia in a local hospital developed multiple massive gas embolisms. At closure, surgeons irrigated the incision wound with hydrogen peroxide. Soon after the irrigation, the patient suddenly developed tachycardia, hypotension, and rapid oxygen desaturation. Subsequently, patient progressed into unconsciousness and right hemianopsia quadriplegia. Computed tomography (CT) scan showed multiple hypointensity spots around the brain due to cerebral gas embolism, which indicated the pneumoencephalos. The likely mechanism was the absorption of hydrogen peroxide into blood. When the amount of oxygen evolved exceeded its maximal blood solubility, venous embolization occurred. Though the patient was treated with supportive treatments and hyperbaric oxygen, she did not get full recovery and was left with severe long-term cerebral injury. PMID:25688310

  14. A female soccer player with recurrent haemoptysis and iron deficiency anaemia: idiopathic pulmonary haemosiderosis (IPH)-case report and literature review.

    PubMed

    Schroers, Roland; Bonella, Francesco; Tötsch, Martin; Costabel, Ulrich

    2010-01-01

    A 19-year-old woman presented with repeated episodes of haemoptysis and shortness of breath. Blood tests revealed iron deficiency anaemia and chest imaging studies showed bilateral lung opacities. In further laboratory tests and technical examination including bronchoalveolar lavage and transbronchial lung biopsy, pulmonary embolism, cardiac disease, and pulmonary vasculitis due to autoimmune disease were ruled out. Finally, a diagnosis of idiopathic pulmonary haemosiderosis (IPH) was made in January 2008. The patient was treated with prednisone, azathioprine, and oral iron supplementation. Subsequently, the patient's condition and haemoglobin value improved notably. In May 2009, the patient was in full disease remission including a normal blood count and normal iron parameters. IPH is a rare cause of diffuse alveolar haemorrhage of unknown origin. It occurs most frequently in children and adolescents and typically presents with recurrent haemoptysis due to alveolar bleeding. However, pulmonary signs and symptoms often are obscure in children. In these cases iron deficiency anaemia is the prominent clinical finding. The purpose of this case report is to increase awareness of IPH as a possible cause of recurrent haemoptysis and anaemia. PMID:22242052

  15. A female soccer player with recurrent haemoptysis and iron deficiency anaemia: idiopathic pulmonary haemosiderosis (IPH)—case report and literature review

    PubMed Central

    Schroers, Roland; Bonella, Francesco; Tötsch, Martin; Costabel, Ulrich

    2010-01-01

    A 19-year-old woman presented with repeated episodes of haemoptysis and shortness of breath. Blood tests revealed iron deficiency anaemia and chest imaging studies showed bilateral lung opacities. In further laboratory tests and technical examination including bronchoalveolar lavage and transbronchial lung biopsy, pulmonary embolism, cardiac disease, and pulmonary vasculitis due to autoimmune disease were ruled out. Finally, a diagnosis of idiopathic pulmonary haemosiderosis (IPH) was made in January 2008. The patient was treated with prednisone, azathioprine, and oral iron supplementation. Subsequently, the patient’s condition and haemoglobin value improved notably. In May 2009, the patient was in full disease remission including a normal blood count and normal iron parameters. IPH is a rare cause of diffuse alveolar haemorrhage of unknown origin. It occurs most frequently in children and adolescents and typically presents with recurrent haemoptysis due to alveolar bleeding. However, pulmonary signs and symptoms often are obscure in children. In these cases iron deficiency anaemia is the prominent clinical finding. The purpose of this case report is to increase awareness of IPH as a possible cause of recurrent haemoptysis and anaemia. PMID:22242052

  16. Exercise-induced haemoptysis as a rare presentation of a rare lung disease.

    PubMed

    Mihalek, Andrew D; Haney, Carissa; Merino, Maria; Roy-Chowdhuri, Sinchita; Moss, Joel; Olivier, Kenneth N

    2016-09-01

    Amyloid primarily affecting the lungs is a seldom seen clinical entity. This case discusses the work-up of a patient presenting with exercise-induced haemoptysis and diffuse cystic lung disease on radiographic imaging. The common clinical and radiographic findings of diffuse cystic lung diseases as well as a brief overview of pulmonary amyloid are presented. PMID:27272655

  17. Massive Hemoptysis due to Endotracheal Hemangioma: A Case Report and Literature Review

    PubMed Central

    Yu, Yeonsil; Lee, Suhyeon; An, Jinyoung; Lee, Jeongmin; Kim, Jihoon; Lee, Youngkyung; Jung, Eunah; Song, Sookhee; Kim, Hyeok

    2015-01-01

    Tracheal hemangioma is a rare benign vascular tumor in adults. We reported a case of massive hemoptysis caused by a cavernous hemangioma in a 75-year-old man. This is the first report, to our knowledge, of a tracheal cavernous hemangioma that presented with massive hemoptysis. The lesion was removed with a CO2 laser under rigid laryngoscopy. Endovascular tumors, such as tracheobronchial hemangiomas, should be considered a diagnostic option in cases of massive hemoptysis without a significant underlying lung lesion. PMID:25861344

  18. Massive hemoperitoneum due to a ruptured corpus luteum cyst in a patient with congenital hypofibrinogenemia.

    PubMed

    Kim, Jong-Hyun; Jeong, So-Young; Cho, Dong-Hyu

    2015-09-01

    Congenital afibrinogenemia/hypofibrinogenemia is a rare inherited hematologic disorder in which a patient lacks or has insufficient level of fibrinogen, the blood coagulation factor I. The incidence of this uncommon disease is 1 to 2 per 1 million individuals. Hence, massive hemoperitoneum caused by ovulation in a woman with congenital afibrogenemia is also a very rare clinical condition. Massive hemoperitoneum usually presents as acute abdominal pain with potential findings of peritonitis including abdominal distention, hypotension and tachycardia with critical consequences. We performed emergent endoscopic surgery for hemoperitoneum caused by a ruptured corpus luteum cyst in a patient with congenital hypofibrinogenemia. To the best of our knowledge, this was the first case report of such treatment in Korea. PMID:26430672

  19. Multidetector CT diagnosis of massive hemobilia due to gallbladder polyposis in a child with metachromatic leukodystrophy.

    PubMed

    Wanner, Matthew R; Karmazyn, Boaz; Fan, Rong

    2015-12-01

    Hemobilia secondary to gallbladder polyposis is rare in children but has been reported in a few children with metachromatic leukodystrophy. We present a case with preoperative multidetector computed tomography (MDCT) diagnosis of massive hemobilia caused by gallbladder polyposis in a patient with metachromatic leukodystrophy. Our report highlights the importance of both awareness of the association of gallbladder polyposis with other syndromes such as metachromatic leukodystrophy as well as the possibility of this entity presenting with life-threatening bleeding. PMID:26160127

  20. Central hyperventilation syndrome due to massive pneumocephalus after endoscopic third ventriculostomy: a case report.

    PubMed

    Park, Euiseok; Kim, Heezoo; Lim, Byung Gun; Lee, Dong Kyu; Chung, Dongik

    2016-08-01

    Pneumocephalus is common after brain surgeries, but usually is not substantial enough to cause serious complications. We recently encountered a case of post-operative tachypnea after an endoscopic 3rd ventriculostomy. At first, we thought that the hyperventilation was the result of residual paralysis after emergence from anesthesia, but during further evaluation we found a massive pneumocephalus. In such unusual post-operative situations, physicians should consider surgery-related complications as the possible cause as well, along with the anesthetic factors. PMID:27482322

  1. Central hyperventilation syndrome due to massive pneumocephalus after endoscopic third ventriculostomy: a case report

    PubMed Central

    Park, Euiseok; Lim, Byung Gun; Chung, Dongik

    2016-01-01

    Pneumocephalus is common after brain surgeries, but usually is not substantial enough to cause serious complications. We recently encountered a case of post-operative tachypnea after an endoscopic 3rd ventriculostomy. At first, we thought that the hyperventilation was the result of residual paralysis after emergence from anesthesia, but during further evaluation we found a massive pneumocephalus. In such unusual post-operative situations, physicians should consider surgery-related complications as the possible cause as well, along with the anesthetic factors. PMID:27482322

  2. Massive outbreaks of Noctiluca scintillans blooms in the Arabian Sea due to spread of hypoxia.

    PubMed

    do Rosário Gomes, Helga; Goes, Joaquim I; Matondkar, S G P; Buskey, Edward J; Basu, Subhajit; Parab, Sushma; Thoppil, Prasad

    2014-01-01

    In the last decade, the northern Arabian Sea has witnessed a radical shift in the composition of winter phytoplankton blooms, which previously comprised mainly of diatoms, the unicellular, siliceous photosynthetic organisms favoured by nutrient-enriched waters from convective mixing. These trophically important diatom blooms have been replaced by widespread blooms of a large, green dinoflagellate, Noctiluca scintillans, which combines carbon fixation from its chlorophyll-containing endosymbiont with ingestion of prey. Here, we report that these massive outbreaks of N. scintillans during winter are being facilitated by an unprecedented influx of oxygen deficient waters into the euphotic zone and by the extraordinary ability of its endosymbiont Pedinomonas noctilucae to fix carbon more efficiently than other phytoplankton under hypoxic conditions. We contend that N. scintillans blooms could disrupt the traditional diatom-sustained food chain to the detriment of regional fisheries and long-term health of an ecosystem supporting a coastal population of nearly 120 million people. PMID:25203785

  3. Postoperative Massive Pulmonary Embolism Due to Superficial Vein Thrombosis of the Upper Limb

    PubMed Central

    Cascella, Marco; Viscardi, Daniela; Bifulco, Francesca; Cuomo, Arturo

    2016-01-01

    It is well known that deep vein thrombosis of the upper extremities is linked to high morbidity/mortality, resulting in 12-20% of all documented pulmonary embolism; however, there are few data about thromboembolism originating from a vein and/or a branch of a superficial vein of the upper extremities. Pulmonary embolism secondary to upper limb superficial vein thrombosis (not combined with upper extremities deep vein thrombosis) is a very rare clinical manifestation with few cases reported in the literature. We report a rare case of thrombophlebitis in departure from a superficial branch of the cephalic vein of the right arm, complicated by cardiac arrest secondary to a massive pulmonary embolism in a patient who underwent major surgery for ovarian cancer. We discuss on the numerous thrombotic risk factors, triggering a cascade of reactions and resulting in a potential fatal clinical manifestation. PMID:26985256

  4. Gastric wall ischemia following massive gastric distension due to peptic pyloric stenosis: a case report.

    PubMed

    Santos, Tatiana; Freitas, Carla; Pinto-de-Sousa, João

    2016-01-01

    Gastric necrosis is a rare entity mainly due to the rich collateral blood flow the stomach is supplied by. Acute gastric dilation is one of the described underlying causes, and although not fully understood, many potential alterations, such as vascular compression, herniation, volvulus, acute necrotizing gastritis, complications after abdominal surgery, anorexia, bulimia nervosa, trauma, exposure to caustic materials, diabetes, medications, infections, debilitating chronic illness, gastric outlet obstruction, aerophagia and acute pancreatitis have been described. In this report, we present a case of partial gastric ischemia with necrosis and consequent perforation of the lesser curvature of the stomach, as a result of gastric outlet obstruction due to pyloric stenosis. The patient underwent an emergency laparotomy. An atypical gastrectomy and a Heineke-Mikulicz pyloroplasty were performed. We emphasize the need for the quick recognition of this condition and for the urgent management because of the high mortality rate associated with undiagnosed gastric necrosis. PMID:26851051

  5. Gastric wall ischemia following massive gastric distension due to peptic pyloric stenosis: a case report

    PubMed Central

    Santos, Tatiana; Freitas, Carla; Pinto-de-Sousa, João

    2016-01-01

    Gastric necrosis is a rare entity mainly due to the rich collateral blood flow the stomach is supplied by. Acute gastric dilation is one of the described underlying causes, and although not fully understood, many potential alterations, such as vascular compression, herniation, volvulus, acute necrotizing gastritis, complications after abdominal surgery, anorexia, bulimia nervosa, trauma, exposure to caustic materials, diabetes, medications, infections, debilitating chronic illness, gastric outlet obstruction, aerophagia and acute pancreatitis have been described. In this report, we present a case of partial gastric ischemia with necrosis and consequent perforation of the lesser curvature of the stomach, as a result of gastric outlet obstruction due to pyloric stenosis. The patient underwent an emergency laparotomy. An atypical gastrectomy and a Heineke–Mikulicz pyloroplasty were performed. We emphasize the need for the quick recognition of this condition and for the urgent management because of the high mortality rate associated with undiagnosed gastric necrosis. PMID:26851051

  6. Multiple esophageal variceal ruptures with massive ascites due to myelofibrosis-induced portal hypertension

    PubMed Central

    Tokai, Koichi; Miyatani, Hiroyuki; Yoshida, Yukio; Yamada, Shigeki

    2012-01-01

    A 75-year old man had been diagnosed at 42 years of age as having polycythemia vera and had been monitored at another hospital. Progression of anemia had been recognized at about age 70, and the patient was thus referred to our center in 2008 where secondary myelofibrosis was diagnosed based on bone marrow biopsy findings. Hematemesis due to rupture of esophageal varices occurred in January and February of 2011. The bleeding was stopped by endoscopic variceal ligation. Furthermore, in March of the same year, hematemesis recurred and the patient was transported to our center. He was in irreversible hemorrhagic shock and died. The autopsy showed severe bone marrow fibrosis with mainly argyrophilic fibers, an observation consistent with myelofibrosis. The liver weighed 1856 g the spleen 1572 g, indicating marked hepatosplenomegaly. The liver and spleen both showed extramedullary hemopoiesis. Myelofibrosis is often complicated by portal hypertension and is occasionally associated with gastrointestinal hemorrhage due to esophageal varices. A patient diagnosed as having myelofibrosis needs to be screened for esophageal/gastric varices. Myelofibrosis has a poor prognosis. Therefore, it is necessary to carefully decide the therapeutic strategy in consideration of the patient’s concomitant conditions, treatment invasiveness and quality of life. PMID:22851873

  7. [Massive pulmonary embolism due to hydatid vesicles. Report of a case (author's transl)].

    PubMed

    Grau Junyent, J M; Vernet Vernet, M; Fernández-Huerta, J M; Ramírez Ruz, J; Urbano-Márquez, A; Rozman, C

    1980-04-25

    A patient with hepatic and peritoneal hydatidosis suffered acute episodes of restrictive bronchial disease for the last 2 years. The patient was admitted during the course of one of this acute episodes with clinical symptoms of pulmonary embolism. Supportive therapeutic measures were prescribed, but the patient died 12 hours latter. Autopsy revealed hepatic, peritoneal and pulmonary hidatidosis as well as multiple pulmonary thromboembolisms due to hydatid vesicles. Literature on this subject is reviewed, and different clinical forms and therapeutic possibilities are discussed. The importance of small therapeutic possibilities are discussed. The importance of small recurrent hydatid embolisms in the pathogenesis of acute or subacute cor pulmonale in patients with liver hydatidosis is stressed. PMID:7374237

  8. Multi-scale predictions of massive conifer mortality due to chronic temperature rise

    USGS Publications Warehouse

    McDowell, Nathan G.; Williams, A.P.; Xu, C.; Pockman, W. T.; Dickman, L. T.; Sevanto, S.; Pangle, R.; Limousin, J.; Plaut, J.J.; Mackay, D.S.; Ogee, J.; Domec, Jean-Christophe; Allen, Craig D.; Fisher, Rosie A.; Jiang, X.; Muss, J.D.; Breshears, D.D.; Rauscher, Sara A.; Koven, C.

    2015-01-01

    Global temperature rise and extremes accompanying drought threaten forests and their associated climatic feedbacks. Our ability to accurately simulate drought-induced forest impacts remains highly uncertain in part owing to our failure to integrate physiological measurements, regional-scale models, and dynamic global vegetation models (DGVMs). Here we show consistent predictions of widespread mortality of needleleaf evergreen trees (NET) within Southwest USA by 2100 using state-of-the-art models evaluated against empirical data sets. Experimentally, dominant Southwest USA NET species died when they fell below predawn water potential (Ψpd) thresholds (April–August mean) beyond which photosynthesis, hydraulic and stomatal conductance, and carbohydrate availability approached zero. The evaluated regional models accurately predicted NET Ψpd, and 91% of predictions (10 out of 11) exceeded mortality thresholds within the twenty-first century due to temperature rise. The independent DGVMs predicted ≥50% loss of Northern Hemisphere NET by 2100, consistent with the NET findings for Southwest USA. Notably, the global models underestimated future mortality within Southwest USA, highlighting that predictions of future mortality within global models may be underestimates. Taken together, the validated regional predictions and the global simulations predict widespread conifer loss in coming decades under projected global warming.

  9. Multi-scale predictions of massive conifer mortality due to chronic temperature rise

    NASA Astrophysics Data System (ADS)

    McDowell, N. G.; Williams, A. P.; Xu, C.; Pockman, W. T.; Dickman, L. T.; Sevanto, S.; Pangle, R.; Limousin, J.; Plaut, J.; Mackay, D. S.; Ogee, J.; Domec, J. C.; Allen, C. D.; Fisher, R. A.; Jiang, X.; Muss, J. D.; Breshears, D. D.; Rauscher, S. A.; Koven, C.

    2016-03-01

    Global temperature rise and extremes accompanying drought threaten forests and their associated climatic feedbacks. Our ability to accurately simulate drought-induced forest impacts remains highly uncertain in part owing to our failure to integrate physiological measurements, regional-scale models, and dynamic global vegetation models (DGVMs). Here we show consistent predictions of widespread mortality of needleleaf evergreen trees (NET) within Southwest USA by 2100 using state-of-the-art models evaluated against empirical data sets. Experimentally, dominant Southwest USA NET species died when they fell below predawn water potential (Ψpd) thresholds (April-August mean) beyond which photosynthesis, hydraulic and stomatal conductance, and carbohydrate availability approached zero. The evaluated regional models accurately predicted NET Ψpd, and 91% of predictions (10 out of 11) exceeded mortality thresholds within the twenty-first century due to temperature rise. The independent DGVMs predicted >=50% loss of Northern Hemisphere NET by 2100, consistent with the NET findings for Southwest USA. Notably, the global models underestimated future mortality within Southwest USA, highlighting that predictions of future mortality within global models may be underestimates. Taken together, the validated regional predictions and the global simulations predict widespread conifer loss in coming decades under projected global warming.

  10. Human immunodeficiency virus infection in a child revealed by a massive purulent pericarditis mistaken for a liver abscess due to Staphylococcus aureus

    PubMed Central

    Bernadette, Ngo Nonga; Kamgaing, N.; Monebenimp, F.; Simeu, C.

    2015-01-01

    Massive purulent andacute pericarditis in children is a life-threatening disease associated with high mortality. It has been described tocomplicate usuallya bronchopulmonary infectionbut is currently uncommon in the era of antibiotics. Acute and massive purulent pericarditis has been rarely reported in children in association with human immunodeficiency virus (HIV) infection. This is a case of a10-year-old boy who presented with signs of sepsis and cardiac tamponade due to a massive staphylococcal purulent pericarditis complicating an unknown HIV infection. The child underwent pericardiectomy, intensive treatment, and survived this life-threatening disease. PMID:25659555

  11. [Cesarean section for case with preoperatively-suspected placenta accrete followed by hysterectomy due to uncontrollable massive bleeding].

    PubMed

    Kono, Yasuo; Sawada, Maiko; Kano, Tatsuhiko

    2007-12-01

    A 42-yr-old pregnant woman highly suspicious of the placenta accreta was scheduled for cesarean section (c-section) under general anesthesia. She had received emergency c-section for the placenta previa at 36 years of age and three episodes of intrauterine curettage for spontaneous abortion. While the possibility of placenta accreta was pointed out and the risks accompanying with it were explained at the 7th week of pregnancy, she insisted on having a baby. C-section was intended at around the 30th week of pregnancy and 1,200 ml of autologus blood was stored for the predictable massive bleeding. Bilateral embolization of the internal iliac artery was also planned. The baby was delivered uneventfully. However, the adherence of the placenta was so tight that the placenta could not be separated from the uterine wall. The arterial embolization immediately after the delivery did not work as effectively as to control massive bleeding. It took about 1 hour to control the massive bleeding of up to 9000 ml by difficult hysterectomy. Since we had prepared for such a situation, we could well catch up with the massive bleeding. The mother and baby were discharged well from the hospital 29th day after the c-section. PMID:18078102

  12. Endoscopic variceal ligation caused massive bleeding due to laceration of an esophageal varicose vein with tissue glue emboli

    PubMed Central

    Wei, Xiu-Qing; Gu, Hua-Ying; Wu, Zhi-E; Miao, Hui-Biao; Wang, Pei-Qi; Wen, Zhuo-Fu; Wu, Bin

    2014-01-01

    Endoscopic variceal obturation of gastric varices with tissue glue is considered the first choice for management of gastric varices, and is usually safe and effective. However, there is still a low incidence of complications and some are even fatal. Here, we present a case in which endoscopic variceal ligation caused laceration of the esophageal varicose vein with tissue glue emboli and massive bleeding after 3 mo. Cessation of bleeding was achieved via variceal sclerotherapy using a cap-fitted gastroscope. Methods of recognizing an esophageal varicose vein with tissue glue plug are discussed. PMID:25400482

  13. Endoscopic variceal ligation caused massive bleeding due to laceration of an esophageal varicose vein with tissue glue emboli.

    PubMed

    Wei, Xiu-Qing; Gu, Hua-Ying; Wu, Zhi-E; Miao, Hui-Biao; Wang, Pei-Qi; Wen, Zhuo-Fu; Wu, Bin

    2014-11-14

    Endoscopic variceal obturation of gastric varices with tissue glue is considered the first choice for management of gastric varices, and is usually safe and effective. However, there is still a low incidence of complications and some are even fatal. Here, we present a case in which endoscopic variceal ligation caused laceration of the esophageal varicose vein with tissue glue emboli and massive bleeding after 3 mo. Cessation of bleeding was achieved via variceal sclerotherapy using a cap-fitted gastroscope. Methods of recognizing an esophageal varicose vein with tissue glue plug are discussed. PMID:25400482

  14. Massive spalling of intermetallic compounds in solder-substrate reactions due to limited supply of the active element

    SciTech Connect

    Yang, S. C.; Ho, C. E.; Chang, C. W.; Kao, C. R.

    2007-04-15

    Massive spalling of intermetallic compounds has been reported in the literature for several solder/substrate systems, including SnAgCu soldered on Ni substrate, SnZn on Cu, high-Pb PbSn on Cu, and high-Pb PbSn on Ni. In this work, a unified thermodynamic argument is proposed to explain this rather unusual phenomenon. According to this argument, two necessary conditions must be met. The number one condition is that at least one of the reactive constituents of the solder must be present in a limited amount, and the second condition is that the soldering reaction has to be very sensitive to its concentration. With the growth of intermetallic, more and more atoms of this constituent are extracted out of the solder and incorporated into the intermetallic. As the concentration of this constituent decreases, the original intermetallic at the interface becomes a nonequilibrium phase, and the spalling of the original intermetallic occurs.

  15. Massively parallel rRNA gene sequencing exacerbates the potential for biased community diversity comparisons due to variable library sizes

    SciTech Connect

    Gihring, Thomas; Green, Stefan; Schadt, Christopher Warren

    2011-01-01

    Technologies for massively parallel sequencing are revolutionizing microbial ecology and are vastly increasing the scale of ribosomal RNA (rRNA) gene studies. Although pyrosequencing has increased the breadth and depth of possible rRNA gene sampling, one drawback is that the number of reads obtained per sample is difficult to control. Pyrosequencing libraries typically vary widely in the number of sequences per sample, even within individual studies, and there is a need to revisit the behaviour of richness estimators and diversity indices with variable gene sequence library sizes. Multiple reports and review papers have demonstrated the bias in non-parametric richness estimators (e.g. Chao1 and ACE) and diversity indices when using clone libraries. However, we found that biased community comparisons are accumulating in the literature. Here we demonstrate the effects of sample size on Chao1, ACE, CatchAll, Shannon, Chao-Shen and Simpson's estimations specifically using pyrosequencing libraries. The need to equalize the number of reads being compared across libraries is reiterated, and investigators are directed towards available tools for making unbiased diversity comparisons.

  16. Haemoptysis and left upper quadrant abdominal pain: an unusual presentation of partial thoracic migration of an adjustable gastric band's tube

    PubMed Central

    Carvalho, César; Milheiro, António; Manso, António Canaveira; Castro Sousa, Francisco

    2013-01-01

    Laparoscopic gastric banding is considered the safest bariatric procedure, holding satisfactory long-term weight loss results, low rates of early complications and negligible mortality. Long-term follow-up are showing a high prevalence of late complications. We describe the case of a 40-year-old female patient, with a medical history of laparoscopic gastric banding, admitted in the emergency department complaining of haemoptysis, left upper quadrant abdominal pain and a slight tachycardia. After an exhaustive clinical evaluation with laboratorial and radiological assessments, diagnosis of partial thoracic migration of the band's tube was established. Despite the unusual clinical setting, this case emphasises the necessity of awareness for the potential long-term complications of gastric banding either from primary or secondary care providers. PMID:23420734

  17. Pulmonary hypoplasia on preterm infant associated with diffuse chorioamniotic hemosiderosis caused by intrauterine hemorrhage due to massive subchorial hematoma: report of a neonatal autopsy case.

    PubMed

    Yamada, Sohsuke; Marutani, Takamitsu; Hisaoka, Masanori; Tasaki, Takashi; Nabeshima, Atsunori; Shiraishi, Mika; Sasaguri, Yasuyuki

    2012-08-01

    A male infant born prematurely at 31 weeks of gestation weighed 789 g and had mildly brown-colored oral/tracheal aspirates at delivery. The amniotic fluid was also discolored, and its index was below 5. The patient died of hypoxemic respiratory and cardiac failure 2 hours after birth. The maternal profiles showed placenta previa and intrauterine growth restriction (IUGR) at 22 weeks of gestation, and revealed recurrent episodes of antenatal and substantial vaginal bleeding and oligohydramnios, indicating chronic abruption-oligohydramnios sequence. The thickened placenta, weighing 275 g, grossly displayed unevenness and diffuse opacity with green to brown discoloration in the chorioamniotic surface, and revealed chronic massive subchorial hematomas (Breus' mole) with old peripheral blood clot, circumvallation, and infarction. Microscopically, diffuse Berlin-blue staining-positive hemosiderin deposits were readily encountered in the chorioamniotic layers of the chorionic plate, consistent with diffuse chorioamniotic hemosiderosis (DCH) due to Breus' mole, accompanied by diffuse amniotic necrosis. At autopsy, an external examination showed several surface anomalies and marked pulmonary hypoplasia, 0.006 (less 0.012) of lung:body weight ratio. Since Breus' mole has a close relationship with intrauterine hemorrhage, resulting in DCH, IUGR, and/or pulmonary hypoplasia of the newborn, the present features might be typical. PMID:22827763

  18. Massive Fibroid

    PubMed Central

    Weekes, Leroy R.

    1977-01-01

    This ten-year study of the massive fibroid at the Queen of Angels Hospital will reveal an average of 66 cases per year which could be classified as large and massive. Only about ten cases per year qualify as massive (four gestational months or larger). There were none considered giant size (25 lbs or more). The literature is replete with these, one of which (weighing 100.2 lbs) will be reported in detail. The mortality rate continues to be considerable in these (14.8 to 16.7 percent). In the smaller tumors, mortality is rare and morbidity is minimal. Bleeding, pain, and pressure symptoms, due to impingement on neighboring organs, are the principal symptoms. Sarcomatous change, fortunately, still remains quite rare. Treatment usually involves a pre-operative dilatation and curettage when bleeding is a problem, followed by total abdominal hysterectomy and bilateral salpingo-oophorectomy where indicated. Appendectomy is usually incidental. Anesthesia is usually spinal, if not otherwise contraindicated. Ultrasound is a new and refined diagnostic tool. PMID:833892

  19. Case with a Nonreassuring Fetal Status Induced by Massive Hematemesis due to Mallory-Weiss Tear That Required Emergency Cesarean Section at 38 Weeks' Gestation

    PubMed Central

    Suzuki, Takashi; Wagata, Maiko; Konno, Hiroko; Ito, Takahiro; Torii, Yuichi; Murakoshi, Takeshi

    2015-01-01

    We describe a rare case of Mallory-Weiss tear with massive hematemesis at 38 weeks' gestation. A 35-year-old woman presented with epigastralgia followed by massive hematemesis. An emergency endoscopy indicated active pulsatile bleeding at the esophagocardial junction. Although an emergency endoscopic hemostasis was successful, late decelerations without acceleration on cardiotocogram were observed. Therefore, the patient underwent emergency cesarean section, along with blood transfusion, following the endoscopic hemostasis. The hemoglobin level just before the operation was 5.1 g/dL. We suspected that massive hematemesis induced maternal acute anemia and hypovolemia, which resulted in a nonreassuring fetal status. Hence, urgent endoscopic hemostasis, adequate blood transfusion, and emergency cesarean section were needed. Mallory-Weiss tear during the third trimester may have a possibility of massive hematemesis and urgent blood transfusion, emergency endoscopic hemostasis, and emergency cesarean section may be needed. PMID:26881157

  20. Temporary abdominal closure and delayed biliary reconstruction due to massive bleeding in patients undergoing liver transplantation: an old trick in a new indication

    PubMed Central

    Komorowski, Andrzej L.; Li, Wei‐Feng; Millan, Carlos A.; Huang, Tun‐Sung; Yong, Chee‐Chien; Lin, Tsan‐Shiun; Lin, Ting‐Lung; Jawan, Bruno; Chen, Chao‐Long

    2016-01-01

    Abstract Background Massive bleeding during liver transplantation (LT) is difficult to manage surgical event. Perihepatic packing (PP) and temporary abdominal closure (TAC) with delayed biliary reconstruction (DBR) can be applied in these circumstances. Method A prospective database of LT in a major transplant center was analyzed to identify patients with massive uncontrollable bleeding during LT that was resolved by PP, TAC, and DBR. Results From January 2009 to July 2013, 20 (3.6%) of 547 patients who underwent LT underwent DBR. Mean intraoperative blood loss was 20,500 ml at the first operation. The DBR was performed with a mean of 55.2 h (16–110) after LT. Biliary reconstruction included duct‐to‐duct (n = 9) and hepatico‐jejunostomy (n = 11). Complications occurred in eight patients and included portal vein thrombosis, cholangitis, severe bacteremia, pneumonia. There was one in‐hospital death. In the follow‐up of 18 to 33 months we have seen one patient died 9 months after transplantation. The remaining 18 patients are alive and well. Conclusions In case of massive uncontrollable bleeding and bowel edema during LT, the combined procedures of PP, TAC, and DBR offer an alternatively surgical option to solve the tough situation. PMID:26692574

  1. A DEEP SEARCH FOR MOLECULAR GAS IN TWO MASSIVE LYMAN BREAK GALAXIES AT z = 3 AND 4: VANISHING CO-EMISSION DUE TO LOW METALLICITY?

    SciTech Connect

    Tan, Q.; Gao, Y.; Daddi, E.; Sargent, M.; Béthermin, M.; Bournaud, F.; Elbaz, D.; Pannella, M.; Hodge, J.; Walter, F.; Carilli, C.; Owen, F.; Dannerbauer, H.; Dickinson, M.; Morrison, G.; Riechers, D.

    2013-10-20

    We present deep IRAM Plateau de Bure Interferometer observations, searching for CO-emission toward two massive, non-lensed Lyman break galaxies at z = 3.216 and 4.058. With one low significance CO detection (3.5σ) and one sensitive upper limit, we find that the CO lines are ∼>3-4 times weaker than expected based on the relation between IR and CO luminosities followed by similarly massive galaxies at z = 0-2.5. This is consistent with a scenario in which these galaxies have low metallicity, causing an increased CO-to-H{sub 2} conversion factor, i.e., weaker CO-emission for a given molecular (H{sub 2}) mass. The required metallicities at z > 3 are lower than predicted by the fundamental metallicity relation at these redshifts, consistent with independent evidence. Unless our galaxies are atypical in this respect, detecting molecular gas in normal galaxies at z > 3 may thus remain challenging even with ALMA.

  2. Massive Stars

    NASA Astrophysics Data System (ADS)

    Livio, Mario; Villaver, Eva

    2009-11-01

    Participants; Preface Mario Livio and Eva Villaver; 1. High-mass star formation by gravitational collapse of massive cores M. R. Krumholz; 2. Observations of massive star formation N. A. Patel; 3. Massive star formation in the Galactic center D. F. Figer; 4. An X-ray tour of massive star-forming regions with Chandra L. K. Townsley; 5. Massive stars: feedback effects in the local universe M. S. Oey and C. J. Clarke; 6. The initial mass function in clusters B. G. Elmegreen; 7. Massive stars and star clusters in the Antennae galaxies B. C. Whitmore; 8. On the binarity of Eta Carinae T. R. Gull; 9. Parameters and winds of hot massive stars R. P. Kudritzki and M. A. Urbaneja; 10. Unraveling the Galaxy to find the first stars J. Tumlinson; 11. Optically observable zero-age main-sequence O stars N. R. Walborn; 12. Metallicity-dependent Wolf-Raynet winds P. A. Crowther; 13. Eruptive mass loss in very massive stars and Population III stars N. Smith; 14. From progenitor to afterlife R. A. Chevalier; 15. Pair-production supernovae: theory and observation E. Scannapieco; 16. Cosmic infrared background and Population III: an overview A. Kashlinsky.

  3. Delayed massive hemorrhage due to external iliac artery pseudo-aneurysm and uretero-iliac artery fistula following robotic radical cystectomy and intracorporeal Studer pouch reconstruction: Endovascular management of an unusual complication

    PubMed Central

    Atmaca, Ali Fuat; Canda, Abdullah Erdem; Gumus, Mehmet; Asil, Erem; Balbay, Mevlana Derya

    2013-01-01

    We report a very unusual complication of uretero-iliac artery fistula that developed following robotic radical cystectomy (RARC), bilateral extended pelvic lymph node dissection and intracorporeal Studer pouch reconstruction. Our patient was a 54-year-old male who was admitted 1 month after undergoing robotic surgery due to intermittently occurring massive transurethral bleeding necessitating blood transfusion that stopped by itself. Angiography showed a right external iliac artery pseudo-aneurysm and a fistula tract between the pseudo-aneurysm and Wallace type ureteral anostomosis that was successfully treated by an angiographic endovascular stent insertion at this level. Uretero-iliac artery fistula might occur following RARC, bilateral extended pelvic lymph node dissection and intracorporeal Studer pouch reconstruction leading to intermittently massive transurethral bleeding. Angiography and stenting are important for diagnosis and successful treatment of this rare entity. PMID:24069106

  4. Massive Hemoptysis.

    PubMed

    Rali, Parth; Gandhi, Viral; Tariq, Cheema

    2016-01-01

    Hemoptysis, or coughing of blood, oftentimes triggers anxiety and fear for patients. The etiology of hemoptysis will determine the clinical course, which includes watchful waiting or intensive care admission. Any amount of hemoptysis that compromises the patient's respiratory status is considered massive hemoptysis and should be considered a medical emergency. In this article, we review introduction, definition, bronchial circulation anatomy, etiology, and management of massive hemoptysis. PMID:26919675

  5. Massive Rock Detachments from the Continental slope of the Balsas River Submarine Delta that occur due to Instability of Sediments which Produce Turbidity Currents and Tsunamis

    NASA Astrophysics Data System (ADS)

    Sandoval-Ochoa, J.; Aguayo-Camargo, J.

    2007-05-01

    During the NOAA oceanographic delivery cruise of the US R/V "Roger Revelle" to the Scripps Institution of Oceanography at the University of California in San Diego, California USA, in July 1996; a well calibrated bathymetric equipment, the SeaBeam* 2012, was tested. Good resolutions in data allowed bathymetric mapping to visualize the sea floor relief. Detailed colorful chartographic images showed a portion of the continental slope between the Balsas River Delta and the Middle America Trench and between the Balsas Canyon and La Necesidad Canyon. The surveyed area covered more than 3 000 square kilometers. After the delivery cruise, one of the goals was to measure and analyze the Morphobathymetry of the uneven lower portion of the Balsas River Submarine Delta. So far some of the findings with the morphometric analyses consist of several isolated slump scars that each comprise more than 12 cubic kilometers in volume and a multiple slump scar with an evident steep hollow about 200 cubic kilometers absent of rock. These volumes of rock apparently underwent a remobilization from the slope during the Late Quaternary. The rock detachments occured in relatively small portions but in instantaneous massive displacements because of their instability as well as other identified factors in the region. Over time more and more authors have accepted that coastal cuts or submarine slump scars have been left by sudden movements of rock and fluids. The phenomena that occur in the region in general, are accompanied on one side by potential and kinetic energies like falling bodies, flows and gravity waves, and on the other side, by mass transfer of rock and fluid mobilization like turbidity currents, accumulations, sea wave surges or tsunamis. In some cases the phenomena is produced by another natural triggering forces or by an earthquake. We propose that events like these, i.e. massive detachments and their products such as accumulations, turbidity currents and depositional debrites

  6. THE DISCOVERY OF PERIODIC MODULATIONS IN THE OPTICAL SPECTRA OF GALAXIES, POSSIBLY DUE TO ULTRARAPID LIGHT BURSTS FROM THEIR MASSIVE CENTRAL BLACK HOLES

    SciTech Connect

    Borra, Ermanno F.

    2013-09-10

    A Fourier transform analysis of 2.5 million spectra in the SDSS survey was carried out to detect periodic modulations contained in the intensity versus frequency spectrum. A statistically significant signal was found for 223 galaxies, while the spectra of 0.9 million galaxies were observed. A plot of the periods as a function of redshift clearly shows that the effect is real without any doubt, because the modulations are quantized at two base periods that increase with redshift in two very tight parallel linear relations. We suggest that this result could be caused by light bursts separated by times on the order of 10{sup -13} s, but other causes may be possible. We investigate the hypothesis that the modulation is generated by the Fourier transform of spectral lines, but conclude that this hypothesis is not valid. Although the light burst suggestion implies absurdly high temperatures, it is supported by the fact that the Crab pulsar also has extremely short unresolved pulses (<0.5 ns) that imply similarly high temperatures. Furthermore, the radio spectrum of the Crab pulsar also has spectral bands similar to those that have been detected. Finally, decreasing the signal-to-noise threshold of detection gives results consistent with beamed signals having a small beam divergence, as expected from non-thermal sources that send a jet, like those seen in pulsars. Considering that galaxy centers contain massive black holes, exotic black hole physics may be responsible for the spectral modulation. However, at this stage, this idea is only a hypothesis to be confirmed with further work.

  7. Transport de particules massives dans un fluide turbulent: Application a l'erosion due au sable sur les parois d'une turbine hydraulique

    NASA Astrophysics Data System (ADS)

    Bergeron, Stephen

    Le transport de particules massives par un champ turbulent est un vaste domaine de la mécanique des fluides. Il possède de nombreuses applications comme par exemple le transport de sable dans une turbine hydraulique. En raison de la dureté des grains de quartz et des grandes vitesses de collision avec les parois métalliques, un phénomène d'érosion intensif se produit. Les dommages résultants peuvent diminuer le rendement de la turbine au cours des quelques mois suivant la mise en opération. L'objectif de cette thèse est de mettre au point un outil permettant de prédire ces zones d'érosion. Ce projet de recherche en contexte industriel a été réalisé en collaboration avec la compagnie General Electric Hydro du Canada. Dans un régime hautement turbulent, il est possible d'obtenir une expression suffisamment générale en utilisant une formulation partiellement empirique: l'équation de Basset- Boussinesq-Oseen modifiée. Ce choix de modèle tient compte du niveau de précision recherché et de la méthode numérique employée afin de résoudre la phase fluide. Il permet aussi d'éliminer plusieurs ambiguïtés fréquemment rencontrées dans la littérature et implementées dans certains codes commerciaux courants. La formulation mathématique du problème est effectuée dans un espace mixte Euler-Lagrange. Les paramètres dynamiques sont relies au type de particules et à l'intensité de la turbulence. Le code numérique résultant est le plus performant développé à ce jour (août 1998). Les trajectoires de plusieurs centaines de milliers de particules peuvent être simulées et visualisées de manière interactive sur une station de travail (SGI R4K, R8K et R10K). L'utilisateur du logiciel est libre de se déplacer dans l'espace à l'aide d'un environnement similaire a un ``simulateur de vol''. Il peut ainsi analyser les détails du processus d'érosion de même que l'écoulement du fluide dans la turbine. Les zones d'érosion obtenues à l

  8. Massive intraperitoneal hemorrhage and hypovolemic shock due to rupture of a coronary vessel of a uterine leiomyoma: a report of two cases.

    PubMed

    Akahira, J; Ito, K; Nakamura, R; Yajima, A

    1998-07-01

    Intraperitoneal hemorrhage due to uterine leiomyoma is extremely rare. Recently, we encountered such two cases and herein describe them. Case 1 involved a 34-year-old, nulliparous woman referred to our hospital because of a sudden onset of shock while she was playing a softball game. She had a large abdominal tumor and a hemoperitoneum, and was diagnosed as having a ruptured ovarian tumor. Exploratory laparotomy showed a rupture of the coronary vein of a large uterine leiomyoma. The patient was treated with myomectomy and did well postoperatively. Case 2 involved a 44-year-old, multiparous woman referred to our hospital because of sudden onset of lower abdominal pain while defecating. She had a uterine leiomyoma and a hemoperitoneum, and was diagnosed as having a ruptured splenic artery. Exploratory laparotomy showed rupture of the coronary artery of a uterine leiomyoma. The patient was treated with total abdominal hysterectomy and did well postoperatively. These cases suggest that intraperitoneal hemorrhage associated with uterine leiomyoma, although rare, should be considered in women with hypovolemic shock and a large pelvic mass. PMID:9823782

  9. A 27-year-old woman presenting with refractory hypoxaemic respiratory failure, haemoptysis and thyrotoxicosis: a rare manifestation of propylthiouracil therapy.

    PubMed

    Ortiz-Diaz, Enrique O

    2014-01-01

    Pulmonary manifestations of hyperthyroidism not only include pulmonary hypertension and hydrostatic pulmonary oedema, but also treatment/drug-associated pulmonary diseases have to be considered as an exclusion diagnosis. A 27-year-old woman with hypoxaemic respiratory failure under an arterial-venous extra-corporeal membrane oxygenator (AV-ECMO) was admitted to the intensive care unit (ICU). The patient had progressive dyspnoea with haemoptysis, palpitations and failure to thrive. The patient had Graves' disease treated previously with propylthiouracil (PTU). Diffuse alveolar haemorrhage is a non-specific syndrome characterised by evidence of diffuse alveolar damage, exclusion of infectious aetiology and progressively bloodier bronchoalveolar lavage (and/or 20% hemosiderin laden macrophages on cytological examination). PTU associated perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) vasculitis appears to be more common in younger female patients presenting with leukocytoclastic vasculitis, myalgias and arthralgias. The latter compared to non-drug associated ANCA vasculitis which are more common in older males with visceral involvement. PTU-induced ANCA vasculitis prognosis appears to be better compared to primary ANCA syndromes. PMID:25150234

  10. A 27-year-old woman presenting with refractory hypoxaemic respiratory failure, haemoptysis and thyrotoxicosis: a rare manifestation of propylthiouracil therapy

    PubMed Central

    Ortiz-Diaz, Enrique O

    2014-01-01

    Pulmonary manifestations of hyperthyroidism not only include pulmonary hypertension and hydrostatic pulmonary oedema, but also treatment/drug-associated pulmonary diseases have to be considered as an exclusion diagnosis. A 27-year-old woman with hypoxaemic respiratory failure under an arterial-venous extra-corporeal membrane oxygenator (AV-ECMO) was admitted to the intensive care unit (ICU). The patient had progressive dyspnoea with haemoptysis, palpitations and failure to thrive. The patient had Graves’ disease treated previously with propylthiouracil (PTU). Diffuse alveolar haemorrhage is a non-specific syndrome characterised by evidence of diffuse alveolar damage, exclusion of infectious aetiology and progressively bloodier bronchoalveolar lavage (and/or 20% hemosiderin laden macrophages on cytological examination). PTU associated perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) vasculitis appears to be more common in younger female patients presenting with leukocytoclastic vasculitis, myalgias and arthralgias. The latter compared to non-drug associated ANCA vasculitis which are more common in older males with visceral involvement. PTU-induced ANCA vasculitis prognosis appears to be better compared to primary ANCA syndromes. PMID:25150234

  11. Massive Bleeding and Massive Transfusion

    PubMed Central

    Meißner, Andreas; Schlenke, Peter

    2012-01-01

    Massive bleeding in trauma patients is a serious challenge for all clinicians, and an interdisciplinary diagnostic and therapeutic approach is warranted within a limited time frame. Massive transfusion usually is defined as the transfusion of more than 10 units of packed red blood cells (RBCs) within 24 h or a corresponding blood loss of more than 1- to 1.5-fold of the body's entire blood volume. Especially male trauma patients experience this life-threatening condition within their productive years of life. An important parameter for clinical outcome is to succeed in stopping the bleeding preferentially within the first 12 h of hospital admission. Additional coagulopathy in the initial phase is induced by trauma itself and aggravated by consumption and dilution of clotting factors. Although different aspects have to be taken into consideration when viewing at bleedings induced by trauma compared to those caused by major surgery, the basic strategy is similar. Here, we will focus on trauma-induced massive hemorrhage. Currently there are no definite, worldwide accepted algorithms for blood transfusion and strategies for optimal coagulation management. There is increasing evidence that a higher ratio of plasma and RBCs (e.g. 1:1) endorsed by platelet transfusion might result in a superior survival of patients at risk for trauma-induced coagulopathy. Several strategies have been evolved in the military environment, although not all strategies should be transferred unproven to civilian practice, e.g. the transfusion of whole blood. Several agents have been proposed to support the restoration of coagulation. Some have been used for years without any doubt on their benefit-to-risk profile, whereas great enthusiasm of other products has been discouraged by inefficacy in terms of blood transfusion requirements and mortality or significant severe side effects. This review surveys current literature on fluid resuscitation, blood transfusion, and hemostatic agents currently

  12. Massive transfusion and massive transfusion protocol

    PubMed Central

    Patil, Vijaya; Shetmahajan, Madhavi

    2014-01-01

    Haemorrhage remains a major cause of potentially preventable deaths. Rapid transfusion of large volumes of blood products is required in patients with haemorrhagic shock which may lead to a unique set of complications. Recently, protocol based management of these patients using massive transfusion protocol have shown improved outcomes. This section discusses in detail both management and complications of massive blood transfusion. PMID:25535421

  13. Massive ascites of unknown origin

    PubMed Central

    Yuan, Shi-Min

    2014-01-01

    Massive ascites of unknown origin is an uncommon condition, which represent a diagnostic challenge. Patients with delayed diagnosis and treatment may have a poor prognosis. A 22-year-old female was referred to this hospital due to a 4-year progressive abdominal distension with massive ascites of unknown origin. By thorough investigations, she was eventually diagnosed as chronic calcified constrictive pericarditis. She received pericardiectomy and had an uneventful postoperative course. With a few day paracentesis, ascites did not progress any more. She was doing well at 5-month follow-up and has returned to work. Extracardiac manifestations, such as massive ascites and liver cirrhosis, were rare in patients with constrictive pericarditis. Pericardiectomy can be a radical solution for the treatment of chronic constrictive pericarditis. In order to avoid delayed diagnosis and treatment, physicians have to bear in mind this rare manifestation of chronic calcified constrictive pericarditis. PMID:24600502

  14. Feedback During Massive Star Formation

    NASA Astrophysics Data System (ADS)

    Tanaka, Kei; Tan, Jonathan C.; Zhang, Yichen

    2016-01-01

    We present models of photoionization of massive protostellar cores, and show the impact of this ionization feedback on the efficiency of star formation and its observational features. Based on the Core Accretion scenario, we construct the collapse model of rotating massive-protostellar cloud cores together with a protostellar evolutional calculation, including feedback effects from a MHD disk wind, photoionization and radiation pressure. First, the MHD wind creates a bipolar outflow whose opening angle increases over the timescale of mass accretion. The ionizing luminosity dramatically increases after the protostar reaches ~ 5 Msun due to Kelvin-Helmholz contraction, and the MHD wind is photoionized when the protostellar mass reaches ~ 10 - 20 Msun. As the ionizing and bolometric luminosities increase, the outflow opening angle becomes wider due to radiation pressure feedback. By this combination of feedback processes, the envelope is eroded and the mass infall rate is significantly reduced to that arriving only from the disk-shielded equatorial region. At a protostellar mass of ~ 50 - 100 Msun, depending on the initial core properties, the mass accretion is halted by disk photoevaporation. In this way, feedback significantly reduces the star formation efficiency when forming massive stars from massive cloud cores, which could produce a cutoff at the high-mass end of the initial mass function. Along this evolutionary calculation, we also compute the detailed structure of the photoionized regions using a ray-tracing radiative transfer code and evaluate their emission signatures. Their free-free continuum and recombination line emissions are consistent with the variety of observed radio sources associated with massive protostars, i.e., jets and ultra/hyper-compact HII regions. The comparison between our models and such observations enables us to better define the evolutionary sequence of massive star formation.

  15. Higher dimensional massive bigravity

    NASA Astrophysics Data System (ADS)

    Do, Tuan Q.

    2016-08-01

    We study higher-dimensional scenarios of massive bigravity, which is a very interesting extension of nonlinear massive gravity since its reference metric is assumed to be fully dynamical. In particular, the Einstein field equations along with the following constraint equations for both physical and reference metrics of a five-dimensional massive bigravity will be addressed. Then, we study some well-known cosmological spacetimes such as the Friedmann-Lemaitre-Robertson-Walker, Bianchi type I, and Schwarzschild-Tangherlini metrics for the five-dimensional massive bigravity. As a result, we find that massive graviton terms will serve as effective cosmological constants in both physical and reference sectors if a special scenario, in which reference metrics are chosen to be proportional to physical ones, is considered for all mentioned metrics. Thanks to the constancy property of massive graviton terms, consistent cosmological solutions will be figured out accordingly.

  16. Octonic Massive Field Equations

    NASA Astrophysics Data System (ADS)

    Demir, Süleyman; Kekeç, Seray

    2016-07-01

    In the present paper we propose the octonic form of massive field equations based on the analogy with electromagnetism and linear gravity. Using the advantages of octon algebra the Maxwell-Dirac-Proca equations have been reformulated in compact and elegant way. The energy-momentum relations for massive field are discussed.

  17. Octonic Massive Field Equations

    NASA Astrophysics Data System (ADS)

    Demir, Süleyman; Kekeç, Seray

    2016-03-01

    In the present paper we propose the octonic form of massive field equations based on the analogy with electromagnetism and linear gravity. Using the advantages of octon algebra the Maxwell-Dirac-Proca equations have been reformulated in compact and elegant way. The energy-momentum relations for massive field are discussed.

  18. Massive Oral Decoding.

    ERIC Educational Resources Information Center

    Janicke, Eugene M.

    1981-01-01

    An intensive reading clinic used the Massive Oral Decoding (MOD) technique to help 10 reading disabled students (grades 7 and 8) increase independent reading skills. MOD stresses large amounts of reading practice at the student's independent level. (CL)

  19. Supersymmetrizing massive gravity

    NASA Astrophysics Data System (ADS)

    Malaeb, O.

    2013-07-01

    When four scalar fields with global Lorentz symmetry are coupled to gravity and take a vacuum expectation value, breaking diffeomorphism invariance spontaneously, the graviton becomes massive. This model is supersymmetrized by considering four N=1 chiral superfields with global Lorentz symmetry. The global supersymmetry is promoted to a local one using the rules of tensor calculus of coupling the N=1 supergravity Lagrangian to the four chiral multiplets. When the scalar components of the chiral multiplets zA acquire a vacuum expectation value, both diffeomorphism invariance and local supersymmetry are broken spontaneously. The global Lorentz index A becomes identified with the space-time Lorentz index, making the scalar fields zA vectors and the chiral spinors ψA spin-3/2 Rarita-Schwinger fields. We show that the spectrum of the model in the broken phase consists of a massive spin-2 field, two massive spin-3/2 fields with different mass and a massive vector.

  20. Quantum massive conformal gravity

    NASA Astrophysics Data System (ADS)

    Faria, F. F.

    2016-04-01

    We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed.

  1. Massive star birth: A crossroads of Astrophysics

    NASA Astrophysics Data System (ADS)

    Cesaroni, R.; Felli, M.; Churchwell, E.; Walmsley, M.

    Massive stars, those with between 10 and 100 times the mass of the Sun, are among the rarest stars of all. They live fast and die young, but during their short lives produce the most dramatic effects on the surrounding interstellar medium in terms of dynamics, ionization, and chemical enrichment. Until a few decades ago massive star birth was literally shrouded in mystery, since these stars are born deep inside dense clouds of swirling dust and gas that obscures our view. At IAU S227, more than 200 of the world's leading astronomers presented a cornucopia of new results concerning the birth and infancy of massive stars. These proceedings show the achievements reached in this field, due to observations in the radio at mm and sub-mm wavelengths and in the infrared, and to theoretical models that simulate what happens in the cradle of a massive star.

  2. Massive Stars in Interactive Binaries

    NASA Astrophysics Data System (ADS)

    St.-Louis, Nicole; Moffat, Anthony F. J.

    Massive stars start their lives above a mass of ~8 time solar, finally exploding after a few million years as core-collapse or pair-production supernovae. Above ~15 solar masses, they also spend most of their lives driving especially strong, hot winds due to their extreme luminosities. All of these aspects dominate the ecology of the Universe, from element enrichment to stirring up and ionizing the interstellar medium. But when they occur in close pairs or groups separated by less than a parsec, the interaction of massive stars can lead to various exotic phenomena which would not be seen if there were no binaries. These depend on the actual separation, and going from wie to close including colliding winds (with non-thermal radio emission and Wolf-Rayet dust spirals), cluster dynamics, X-ray binaries, Roche-lobe overflow (with inverse mass-ratios and rapid spin up), collisions, merging, rejuventation and massive blue stragglers, black-hole formation, runaways and gamma-ray bursts. Also, one wonders whether the fact that a massive star is in a binary affects its parameters compared to its isolated equivalent. These proceedings deal with all of these phenomena, plus binary statistics and determination of general physical properties of massive stars, that would not be possible with their single cousins. The 77 articles published in these proceedings, all based on oral talks, vary from broad revies to the lates developments in the field. About a third of the time was spent in open discussion of all participants, both for ~5 minutes after each talk and 8 half-hour long general dialogues, all audio-recorded, transcribed and only moderately edited to yield a real flavour of the meeting. The candid information in these discussions is sometimes more revealing than the article(s) that preceded them and also provide entertaining reading. The book is suitable for researchers and graduate students interested in stellar astrophysics and in various physical processes involved when

  3. Introduction to Massive Gravity

    NASA Astrophysics Data System (ADS)

    de Rham, Claudia

    We review recent progress on massive gravity. We first show how extra dimensions prove to be a useful tool in building theories of modified gravity, including Galileon theories and their DBI extensions. DGP arises from an infinite size extra dimension, and we show how massive gravity arises from `deconstructing' the extra dimension in the vielbein formalism. We then explain how the ghost issue is resolved in that special theory of massive gravity. The viability of such models relies on the Vainshtein mechanism which is best described in terms of Galileons. While its implementation is successful in most of these models it also comes hand in hand with superluminalities and strong coupling which are reviewed and their real consequences are discussed.

  4. Resummation of Massive Gravity

    SciTech Connect

    Rham, Claudia de; Gabadadze, Gregory; Tolley, Andrew J.

    2011-06-10

    We construct four-dimensional covariant nonlinear theories of massive gravity which are ghost-free in the decoupling limit to all orders. These theories resume explicitly all the nonlinear terms of an effective field theory of massive gravity. We show that away from the decoupling limit the Hamiltonian constraint is maintained at least up to and including quartic order in nonlinearities, hence excluding the possibility of the Boulware-Deser ghost up to this order. We also show that the same remains true to all orders in a similar toy model.

  5. Supertwistors and massive particles

    SciTech Connect

    Mezincescu, Luca; Routh, Alasdair J.; Townsend, Paul K.

    2014-07-15

    In the (super)twistor formulation of massless (super)particle mechanics, the mass-shell constraint is replaced by a “spin-shell” constraint from which the spin content can be read off. We extend this formalism to massive (super)particles (with N-extended space–time supersymmetry) in three and four space–time dimensions, explaining how the spin-shell constraints are related to spin, and we use it to prove equivalence of the massive N=1 and BPS-saturated N=2 superparticle actions. We also find the supertwistor form of the action for “spinning particles” with N-extended worldline supersymmetry, massless in four dimensions and massive in three dimensions, and we show how this simplifies special features of the N=2 case. -- Highlights: •Spin-shell constraints are related to Poincaré Casimirs. •Twistor form of 4D spinning particle for spin N/2. •Twistor proof of scalar/antisymmetric tensor equivalence for 4D spin 0. •Twistor form of 3D particle with arbitrary spin. •Proof of equivalence of N=1 and N=2 BPS massive 4D superparticles.

  6. New massive supergravity multiplets

    NASA Astrophysics Data System (ADS)

    Gates, S. James, Jr.; Kuzenko, Sergei M.; Tartaglino-Mazzucchelli, Gabriele

    2007-02-01

    We present new off-shell formulations for the massive superspin-3/2 multiplet. In the massless limit, they reduce respectively to the old minimal (n = -1/3) and non-minimal (n≠-1/3,0) linearized formulations for 4D Script N = 1 supergravity. Duality transformations, which relate the models constructed, are derived.

  7. Massive Stars: Stellar Populations

    NASA Astrophysics Data System (ADS)

    Bianchi, Luciana

    2007-07-01

    Massive stars dominate the chemical and dynamical evolution of the ISM, and ultimately of their parent galaxy and the universe, because of their fast evolution and intense supersonic winds. Four decades ago, the first rocket UV spectra of massive stars revealed the importance of mass loss and began to change our understanding of their evolution. Recently, advances in stellar modeling, and the observation of crucial ions in the far-UV spectral range, led to the resolution of long-standing issues in our understanding of massive star atmospheres. A revised (downwards) calibration of Teff for early spectral types is emerging as a result. Meanwhile, HST imaging, and large ground-based telescopes with multislit spectroscopic capabilities, had opened the possibility of resolved studies of stellar populations in Local Group galaxies, which sample a variety of metallicity and environment conditions. More recently, GALEX is providing a global, deep view of the young stellar populations for hundreds of nearby galaxies, revealing their recent star-formation history and modalities. The wide-field coverage and sensitivity of the GALEX UV imaging, easily detecting extremely low levels of star formation, is again changing some of our views on massive star formation in galaxies.

  8. Massive and Open

    ERIC Educational Resources Information Center

    Fasimpaur, Karen

    2013-01-01

    MOOCs--massive open online courses--are all the rage these days, with hundreds of thousands of participants signing up and investors plunking down millions to get a piece of the pie. Why is there so much excitement about this new disruptive form of online learning, and how does this model apply to professional learning for teachers? Traditional…

  9. Recovery From Giant Eruptions in Massive Stars

    NASA Astrophysics Data System (ADS)

    Kashi, A.; Davidson, K.; Humphreys, R. M.

    2015-12-01

    We perform radiation hydrodynamic simulations to study how very massive stars recover from giant eruptions. The post eruption star experience strong mass loss due to strong winds, driven by radial pulsations in the star*s interior, that operate by the κ-mechanism. The mass loss history obtained in our simulations resembles η Car*s history.

  10. The simultaneous formation of massive stars and stellar clusters

    NASA Astrophysics Data System (ADS)

    Smith, Rowan J.; Longmore, Steven; Bonnell, Ian

    2009-12-01

    We show that massive stars and stellar clusters are formed simultaneously, the global evolution of the forming cluster is what allows the central stars to become massive. We predict that massive star-forming clumps, such as those observed in Motte et al., contract and grow in mass leading to the formation of massive stars. This occurs as mass is continually channelled from large radii on to the central protostars, which can become massive through accretion. Using smoothed particle hydrodynamic simulations of massive star-forming clumps in a giant molecular cloud, we show that clumps are initially diffuse and filamentary, and become more concentrated as they collapse. Simulated interferometry observations of our data provide an explanation as to why young massive star-forming regions show more substructure than older ones. The most massive stars in our model are found within the most bound cluster. Most of the mass accreted by the massive stars was originally distributed throughout the clump at low densities and was later funnelled to the star due to global infall. Even with radiative feedback no massive pre-stellar cores are formed. The original cores are of intermediate mass and gain their additional mass in the protostellar stage. We also find that cores which form low-mass stars exist within the volume from which the high-mass stars accrete, but are largely unaffected by this process.

  11. Massive Binaries: Dynamical and Evolutionary Transformations

    NASA Astrophysics Data System (ADS)

    Gies, D. R.

    2012-12-01

    Observations of massive binaries offer us key insight about the formation, evolution, and destinies of massive stars. Here I review some advances in observational and theoretical studies of massive binaries. Surveys for binaries using radial velocity, photometric, and high angular resolution methods show that the binary frequency is high for O stars in clusters. Evolutionary models for interacting binaries demonstrate the importance of angular momentum transfer during Roche lobe overflow. The mass gainer may reach critical rotation and stem further accretion, and there are many observed cases that show the consequences of such mass loss and transfer. New hydrodynamical models describe colliding wind physics in eccentric binaries such as η Carinae and WR 140. All these research topics are championed by Tony Moffat, and the current richness of this field is due in large measure to his energetic pursuits.

  12. Skyrmions with massive pions

    SciTech Connect

    Battye, Richard A.; Sutcliffe, Paul M.

    2006-05-15

    In the Skyrme model with massless pions, the minimal energy multi-Skyrmions are shell-like, with the baryon density localized on the edges of a polyhedron that is approximately spherical and generically of the fullerene-type. In this paper we show that in the Skyrme model with massive pions these configurations are unstable for sufficiently large baryon number. Using numerical simulations of the full nonlinear field theory, we show that these structures collapse to form qualitatively different stable Skyrmion solutions. These new Skyrmions have a flat structure and display a clustering phenomenon into lower charge components, particularly components of baryon numbers three and four. These new qualitative features of Skyrmions with massive pions are encouraging in comparison with the expectations based on real nuclei.

  13. Massive cold cloud clusters

    NASA Astrophysics Data System (ADS)

    Toth, L. Viktor; Marton, Gabor; Zahorecz, Sarolta

    2015-08-01

    The all-sky Planck catalogue of Galactic Cold Clumps (PGCC, Planck 2015 results XXVIII 2015) allows an almost unbiased study of the early phases of star-formation in our Galaxy. Several thousand of the clumps have also distance estimates allowing a mass, and density determination. The nature of Planck clumps varies from IRDCs to tiny nearby cold clouds with masses ranging from one to several tens of thousands solar masses. Some of the clumps are embedded in GMCs, others are isolated. Some are close or even very close to OB associations, while others lay far from any UV luminous objects.The small scale clustering of these objects was studied with the improved Minimum Spanning Tree method of Cartwright & Whitworth identifying groups in 3D space. As a result also massive cold cloud clusters were identified. We analyse the MST structures, and discuss their relation to ongoing and future massive star formation.

  14. New improved massive gravity

    NASA Astrophysics Data System (ADS)

    Dereli, T.; Yetişmişoğlu, C.

    2016-06-01

    We derive the field equations for topologically massive gravity coupled with the most general quadratic curvature terms using the language of exterior differential forms and a first-order constrained variational principle. We find variational field equations both in the presence and absence of torsion. We then show that spaces of constant negative curvature (i.e. the anti de-Sitter space AdS 3) and constant torsion provide exact solutions.

  15. Young Massive Star Clusters

    NASA Astrophysics Data System (ADS)

    Portegies Zwart, Simon F.; McMillan, Stephen L. W.; Gieles, Mark

    2010-09-01

    Young massive clusters (YMCs) are dense aggregates of young stars that form the fundamental building blocks of galaxies. Several examples exist in the Milky Way Galaxy and the Local Group, but they are particularly abundant in starburst and interacting galaxies. The few YMCs that are close enough to resolve are of prime interest for studying the stellar mass function and the ecological interplay between stellar evolution and stellar dynamics. The distant unresolved clusters may be effectively used to study the star-cluster mass function, and they provide excellent constraints on the formation mechanisms of young cluster populations. YMCs are expected to be the nurseries for many unusual objects, including a wide range of exotic stars and binaries. So far only a few such objects have been found in YMCs, although their older cousins, the globular clusters, are unusually rich in stellar exotica. In this review, we focus on star clusters younger than ˜100 Myr, more than a few current crossing times old, and more massive than ˜104M⊙; the size of the cluster and its environment are considered less relevant as distinguishing parameters. We describe the global properties of the currently known young massive star clusters in the Local Group and beyond, and discuss the state of the art in observations and dynamical modeling of these systems. In order to make this review readable by observers, theorists, and computational astrophysicists, we also review the cross-disciplinary terminology.

  16. HOW MASSIVE ARE MASSIVE COMPACT GALAXIES?

    SciTech Connect

    Muzzin, Adam; Van Dokkum, Pieter; Marchesini, Danilo; Franx, Marijn; Kriek, Mariska; Labbe, Ivo

    2009-11-20

    Using a sample of nine massive compact galaxies at zapprox 2.3 with rest-frame optical spectroscopy and comprehensive U -> 8 mum photometry, we investigate how assumptions in spectral energy distribution (SED) modeling change the stellar mass estimates of these galaxies, and how this affects our interpretation of their size evolution. The SEDs are fitted to tau-models with a range of metallicities, dust laws, and different stellar population synthesis codes. These models indicate masses equal to, or slightly smaller than, our default masses. The maximum difference is 0.16 dex for each parameter considered, and only 0.18 dex for the most extreme combination of parameters. Two-component populations with a maximally old stellar population superposed with a young component provide reasonable fits to these SEDs using the models of Bruzual and Charlot; however, when using models with updated treatment of TP-AGB stars, the fits are poorer. The two-component models predict masses that are 0.08-0.22 dex larger than the tau-models. We also test the effect of a bottom-light initial mass function (IMF) and find that it would reduce the masses of these galaxies by 0.3 dex. Considering the range of allowable masses from the tau-models, two-component fits, and IMF, we conclude that on average these galaxies lie below the mass-size relation of galaxies in the local universe by a factor of 3-9, depending on the SED models used.

  17. Oesophageal duplication cyst presenting as haemoptysis.

    PubMed

    Afzal, Noureen; Adil, Syeda Ezz-e-Rukhshan; Mushtaq, Ammara; Rahman, Arshalooz; Amanullah, Muneer

    2013-05-01

    Duplications of the alimentary tract include a variety of cysts, diverticula, and tubular malformations, all believed to have embryological origin. The cysts are most commonly found in children, and the diagnosis is made in infancy in the majority of patients. We report a case of a two-and-a-half year old child, presenting with the history of repeated episodes of haematemesis. Upper GI endoscopy was unremarkable and the chest x-ray showed no pathology. Computed tomography (CT) angiogram revealed soft tissue density lesion in the right chest at the level of T6. Right thoracotomy suggested a cystic mass close to the oesophagus which was shown on histopathology to be lined with gastric mucosa consistent with oesophageal duplication cyst. To the best of our knowledge, this is the first case of its kind reported from Pakistan. PMID:23757996

  18. Massively Parallel QCD

    SciTech Connect

    Soltz, R; Vranas, P; Blumrich, M; Chen, D; Gara, A; Giampap, M; Heidelberger, P; Salapura, V; Sexton, J; Bhanot, G

    2007-04-11

    The theory of the strong nuclear force, Quantum Chromodynamics (QCD), can be numerically simulated from first principles on massively-parallel supercomputers using the method of Lattice Gauge Theory. We describe the special programming requirements of lattice QCD (LQCD) as well as the optimal supercomputer hardware architectures that it suggests. We demonstrate these methods on the BlueGene massively-parallel supercomputer and argue that LQCD and the BlueGene architecture are a natural match. This can be traced to the simple fact that LQCD is a regular lattice discretization of space into lattice sites while the BlueGene supercomputer is a discretization of space into compute nodes, and that both are constrained by requirements of locality. This simple relation is both technologically important and theoretically intriguing. The main result of this paper is the speedup of LQCD using up to 131,072 CPUs on the largest BlueGene/L supercomputer. The speedup is perfect with sustained performance of about 20% of peak. This corresponds to a maximum of 70.5 sustained TFlop/s. At these speeds LQCD and BlueGene are poised to produce the next generation of strong interaction physics theoretical results.

  19. Inconsistency of topologically massive hypergravity

    NASA Technical Reports Server (NTRS)

    Aragone, C.; Deser, S.

    1985-01-01

    The coupled topologically massive spin-5/2 gravity system in D = 3 dimensions whose kinematics represents dynamical propagating gauge invariant massive spin-5/2 and spin-2 excitations, is shown to be inconsistent, or equivalently, not locally hypersymmetric. In contrast to D = 4, the local constraints on the system arising from failure of the fermionic Bianchi identities do not involve the 'highest spin' components of the field, but rather the auxiliary spinor required to construct a consistent massive model.

  20. Thoracic Cavernous Lymphangioma Provoking Massive Chyloptysis

    PubMed Central

    Ferguson, Robert; Hodges, Jeffrey; Harness-Brumley, Cayce; Girod, Carlos; Bartolome, Sonja

    2013-01-01

    Chyloptysis is a relatively rare embodiment of disease that encompasses a lengthy differential and provides many diagnostic and therapeutic challenges. Presented here is the case of a young woman with massive chyloptysis due to a thoracic cavernous lymphangioma arising in the peripartum period. The severity of her condition mandated the use of cardiopulmonary bypass to resect her lymphangioma. We believe that the extent of her symptoms, etiology of disease, and surgical management represent a unique scenario in the literature. PMID:26425583

  1. Higher dimensional nonlinear massive gravity

    NASA Astrophysics Data System (ADS)

    Do, Tuan Q.

    2016-05-01

    Inspired by a recent ghost-free nonlinear massive gravity in four-dimensional spacetime, we study its higher dimensional scenarios. As a result, we are able to show the constantlike behavior of massive graviton terms for some well-known metrics such as the Friedmann-Lemaitre-Robertson-Walker, Bianchi type I, and Schwarzschild-Tangherlini (anti-) de Sitter metrics in a specific five-dimensional nonlinear massive gravity under an assumption that its fiducial metrics are compatible with physical ones. In addition, some simple cosmological solutions of the five-dimensional massive gravity are figured out consistently.

  2. Massively parallel mathematical sieves

    SciTech Connect

    Montry, G.R.

    1989-01-01

    The Sieve of Eratosthenes is a well-known algorithm for finding all prime numbers in a given subset of integers. A parallel version of the Sieve is described that produces computational speedups over 800 on a hypercube with 1,024 processing elements for problems of fixed size. Computational speedups as high as 980 are achieved when the problem size per processor is fixed. The method of parallelization generalizes to other sieves and will be efficient on any ensemble architecture. We investigate two highly parallel sieves using scattered decomposition and compare their performance on a hypercube multiprocessor. A comparison of different parallelization techniques for the sieve illustrates the trade-offs necessary in the design and implementation of massively parallel algorithms for large ensemble computers.

  3. Massive acute arsenic poisonings.

    PubMed

    Lech, Teresa; Trela, Franciszek

    2005-07-16

    Arsenic poisonings are still important in the field of toxicology, though they are not as frequent as about 20-30 years ago. In this paper, the arsenic concentrations in ante- and post-mortem materials, and also forensic and anatomo-pathological aspects in three cases of massive acute poisoning with arsenic(III) oxide (two of them with unexplained criminalistic background, in which arsenic was taken for amphetamine and one suicide), are presented. Ante-mortem blood and urine arsenic concentrations ranged from 2.3 to 6.7 microg/ml, respectively. Post-mortem tissue total arsenic concentrations were also detected in large concentrations. In case 3, the contents of the duodenum contained as much as 30.1% arsenic(III) oxide. The high concentrations of arsenic detected in blood and tissues in all presented cases are particularly noteworthy in that they are very rarely detected at these concentrations in fatal arsenic poisonings. PMID:15939162

  4. Problems of massive gravities

    NASA Astrophysics Data System (ADS)

    Deser, S.; Izumi, K.; Ong, Y. C.; Waldron, A.

    2015-01-01

    The method of characteristics is a key tool for studying consistency of equations of motion; it allows issues such as predictability, maximal propagation speed, superluminality, unitarity and acausality to be addressed without requiring explicit solutions. We review this method and its application to massive gravity (mGR) theories to show the limitations of these models' physical viability: Among their problems are loss of unique evolution, superluminal signals, matter coupling inconsistencies and micro-acausality (propagation of signals around local closed time-like curves (CTCs)/closed causal curves (CCCs)). We extend previous no-go results to the entire three-parameter range of mGR theories. It is also argued that bimetric models suffer a similar fate.

  5. The evolution of massive stars

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The hypotheses underlying theoretical studies of the evolution of massive model stars with and without mass loss are summarized. The evolutionary tracks followed by the models across theoretical Hertzsprung-Russell (HR) diagrams are compared with the observed distribution of B stars in an HR diagram. The pulsational properties of models of massive star are also described.

  6. [Massive ovarian edema in a 13-year-old girl].

    PubMed

    Sailer, V; Huss, S; Wardelmann, E; Müller, A M

    2013-11-01

    Massive ovarian edema is a rare tumor-like condition found in young women resulting from accumulation of fluid mostly due to partial or intermittent torsion of the ovary or secondary, to a preexisting ovarian lesion. We report a case of a 13-year-old girl presenting with an ovarian mass measuring 16 cm. CA-12-5 levels were slightly elevated. Concerns regarding underlying malignancy led to salpingo-oophorectomy. Pathological evaluation revealed a massive ovarian edema and multiple thromboses of ovarian veins. Differentiating massive ovarian edema from malignant ovarian tumor is crucial to prevent patients from undergoing unnecessary surgery. PMID:23649810

  7. Phase transitions of black holes in massive gravity

    NASA Astrophysics Data System (ADS)

    Fernando, Sharmanthie

    2016-05-01

    In this paper, we have studied thermodynamics of a black hole in massive gravity in the canonical ensemble. The massive gravity theory in consideration here has a massive graviton due to Lorentz symmetry breaking. The black hole studied here has a scalar charge due to the massive graviton and is asymptotically anti-de Sitter (AdS). We have computed various thermodynamical quantities such as temperature, specific heat and free energy. Both the local and global stability of the black hole are studied by observing the behavior of the specific heat and the free energy. We have observed that there is a first-order phase transition between small (SBH) and large black hole (LBH) for a certain range of the scalar charge. This phase transition is similar to the liquid/gas phase transition at constant temperature for a van der Waals fluid. The coexistence curves for the SBH and LBH branches are also discussed in detail.

  8. Massive stars: Starbursts

    NASA Astrophysics Data System (ADS)

    González Delgado, Rosa María

    2007-07-01

    Starbursts are the preferred place where massive stars form; the main source of thermal and mechanical heating in the interstellar medium, and the factory where the heavy elements form. Thus, starbursts play an important role in the origin and evolution of galaxies. Starbursts are bright at ultraviolet (UV) wavelengths, and after the pioneering IUE program, high spatial and spectral resolution UV observations of local starburst galaxies, mainly taken with HST and FUSE, have made relevant contributions to the following issues: a) The determination of the initial mass function (IMF) in violent star forming systems in low and high metallicity environments, and in dense (e.g. in stellar clusters) and diffuse environments: A Salpeter IMF with high-mass stars constrains well the UV properties. b) Stellar clusters are an important mode of star formation in starbursts. c) The role of starbursts in AGN: Nuclear starbursts can dominate the UV light in Seyfert 2 galaxies, having bolometric luminosities similar to the estimated bolometric luminosities of the obscured AGN. d) The interaction between massive stars and the interstellar medium: Outflows in cold, warm and coronal phases leave their imprints on the UV interstellar lines. Outflows of a few hundred km s%u22121 are ubiquitous phenomena in starbursts. Despite the very significant progress obtained over the past two decades of UV observations of starbursts, there are important problems that still need to be solved. High-spatial resolution UV observations of nearby starbursts are crucial to further progress in understanding the violent star formation processes in galaxies, the interaction between the stellar clusters and the interstellar medium, and the variation of the IMF. High-spatial resolution spectra are also needed to isolate the light from the center to the disk in UV luminous galaxies found by GALEX. Thus, a new UV mission furnished with an intermediate spectral resolution spectrograph with high spatial

  9. Massive gauge-flation

    NASA Astrophysics Data System (ADS)

    Nieto, Carlos M.; Rodríguez, Yeinzon

    2016-06-01

    Gauge-flation model at zeroth-order in cosmological perturbation theory offers an interesting scenario for realizing inflation within a particle physics context, allowing us to investigate interesting possible connections between inflation and the subsequent evolution of the Universe. Difficulties, however, arise at the perturbative level, thus motivating a modification of the original model. In order to agree with the latest Planck observations, we modify the model such that the new dynamics can produce a relation between the spectral index ns and the tensor-to-scalar ratio r allowed by the data. By including an identical mass term for each of the fields of the system, we find interesting dynamics leading to slow-roll inflation of the right length. The presence of the mass term has the potential to modify the ns versus r relation so as to agree with the data. As a first step, we study the model at zeroth-order in cosmological perturbation theory, finding the conditions required for slow-roll inflation and the number of e-foldings of inflation. Numerical solutions are used to explore the impact of the mass term. We conclude that the massive version of gauge-flation offers a viable inflationary model.

  10. Massive soliton stars

    NASA Technical Reports Server (NTRS)

    Chiu, Hong-Yee

    1990-01-01

    The structure of nontopological solutions of Einstein field equations as proposed by Friedberg, Lee, and Pang (1987) is examined. This analysis incorporates finite temperature effects and pair creation. Quarks are assumed to be the only species that exist in interior of soliton stars. The possibility of primordial creation of soliton stars in the incomplete decay of the degenerate vacuum in early universe is explored. Because of dominance of pair creation inside soliton stars, the luminosity of soliton stars is not determined by its radiative transfer characteristics, and the surface temperature of soliton stars can be the same as its interior temperature. It is possible that soliton stars are intense X-ray radiators at large distances. Soliton stars are nearly 100 percent efficient energy converters, converting the rest energy of baryons entering the interior into radiation. It is possible that a sizable number of baryons may also be trapped inside soliton stars during early epochs of the universe. In addition, if soliton stars exist they could assume the role played by massive black holes in galactic centers.

  11. Massively Parallel Computing: A Sandia Perspective

    SciTech Connect

    Dosanjh, Sudip S.; Greenberg, David S.; Hendrickson, Bruce; Heroux, Michael A.; Plimpton, Steve J.; Tomkins, James L.; Womble, David E.

    1999-05-06

    The computing power available to scientists and engineers has increased dramatically in the past decade, due in part to progress in making massively parallel computing practical and available. The expectation for these machines has been great. The reality is that progress has been slower than expected. Nevertheless, massively parallel computing is beginning to realize its potential for enabling significant break-throughs in science and engineering. This paper provides a perspective on the state of the field, colored by the authors' experiences using large scale parallel machines at Sandia National Laboratories. We address trends in hardware, system software and algorithms, and we also offer our view of the forces shaping the parallel computing industry.

  12. Superdense Massive Galaxies in the Nearby Universe

    NASA Astrophysics Data System (ADS)

    Trujillo, Ignacio; Cenarro, A. Javier; de Lorenzo-Cáceres, Adriana; Vazdekis, Alexandre; de la Rosa, Ignacio G.; Cava, Antonio

    2009-02-01

    Superdense massive galaxies (re ~ 1 kpc; M ~ 1011 M sun) were common in the early universe (z gsim 1.5). Within some hierarchical merging scenarios, a non-negligible fraction (1%-10%) of these galaxies is expected to survive since that epoch, retaining their compactness and presenting old stellar populations in the present universe. Using the NYU Value-Added Galaxy Catalog from the Sloan Digital Sky Survey Data Release 6, we find only a tiny fraction of galaxies (~0.03%) with re lsim 1.5 kpc and M sstarf gsim 8 × 1010 M sun in the local universe (z < 0.2). Surprisingly, they are relatively young (~2 Gyr) and metal-rich ([Z/H] ~0.2). The consequences of these findings within the current two competing size evolution scenarios for the most massive galaxies ("dry" mergers vs. "puffing up" due to quasar activity) are discussed.

  13. Parallel rendering techniques for massively parallel visualization

    SciTech Connect

    Hansen, C.; Krogh, M.; Painter, J.

    1995-07-01

    As the resolution of simulation models increases, scientific visualization algorithms which take advantage of the large memory. and parallelism of Massively Parallel Processors (MPPs) are becoming increasingly important. For large applications rendering on the MPP tends to be preferable to rendering on a graphics workstation due to the MPP`s abundant resources: memory, disk, and numerous processors. The challenge becomes developing algorithms that can exploit these resources while minimizing overhead, typically communication costs. This paper will describe recent efforts in parallel rendering for polygonal primitives as well as parallel volumetric techniques. This paper presents rendering algorithms, developed for massively parallel processors (MPPs), for polygonal, spheres, and volumetric data. The polygon algorithm uses a data parallel approach whereas the sphere and volume render use a MIMD approach. Implementations for these algorithms are presented for the Thinking Ma.chines Corporation CM-5 MPP.

  14. Electromagnetic properties of massive neutrinos

    SciTech Connect

    Dobrynina, A. A. Mikheev, N. V.; Narynskaya, E. N.

    2013-10-15

    The vertex function for a virtual massive neutrino is calculated in the limit of soft real photons. A method based on employing the neutrino self-energy operator in a weak external electromagnetic field in the approximation linear in the field is developed in order to render this calculation of the vertex function convenient. It is shown that the electric charge and the electric dipole moment of the real neutrino are zero; only the magnetic moment is nonzero for massive neutrinos. A fourth-generation heavy neutrino of mass not less than half of the Z-boson mass is considered as a massive neutrino.

  15. Massive to gauge field reduction and gravitational wave zone information

    NASA Astrophysics Data System (ADS)

    Deser, S.

    2016-07-01

    I analyze the possible relevance of LIGO's gravitational wave detection to the viability of massive gravity models. In GR, a wave zone, where the linearized approximation holds, is guaranteed to exist and the observed wave's amplitude profile can be sufficiently related to the emitting strong field interior to verify that, in this case, it was due to an inspiraling black hole merger. After an excursion to massive spin 1's massless limit, linear massive tensor theory is shown explicitly to propagate only (retarded) maximal, helicity 2, modes to O( m) as m→ 0; however, we don't know if the full theory has a similar "wave zone" governed by the linear model. Even if it does, a much more serious obstacle for massive gravity is to construct a time-varying strong field event to compare with the strong field footprint of LIGO's observed signals.

  16. ATLASGAL - towards a complete sample of massive star forming clumps

    NASA Astrophysics Data System (ADS)

    Urquhart, J. S.; Moore, T. J. T.; Csengeri, T.; Wyrowski, F.; Schuller, F.; Hoare, M. G.; Lumsden, S. L.; Mottram, J. C.; Thompson, M. A.; Menten, K. M.; Walmsley, C. M.; Bronfman, L.; Pfalzner, S.; König, C.; Wienen, M.

    2014-09-01

    By matching infrared-selected, massive young stellar objects (MYSOs) and compact H II regions in the Red MSX Source survey to massive clumps found in the submillimetre ATLASGAL (APEX Telescope Large Area Survey of the Galaxy) survey, we have identified ˜1000 embedded young massive stars between 280° < ℓ < 350° and 10° < ℓ < 60° with | b | < 1.5°. Combined with an existing sample of radio-selected methanol masers and compact H II regions, the result is a catalogue of ˜1700 massive stars embedded within ˜1300 clumps located across the inner Galaxy, containing three observationally distinct subsamples, methanol-maser, MYSO and H II-region associations, covering the most important tracers of massive star formation, thought to represent key stages of evolution. We find that massive star formation is strongly correlated with the regions of highest column density in spherical, centrally condensed clumps. We find no significant differences between the three samples in clump structure or the relative location of the embedded stars, which suggests that the structure of a clump is set before the onset of star formation, and changes little as the embedded object evolves towards the main sequence. There is a strong linear correlation between clump mass and bolometric luminosity, with the most massive stars forming in the most massive clumps. We find that the MYSO and H II-region subsamples are likely to cover a similar range of evolutionary stages and that the majority are near the end of their main accretion phase. We find few infrared-bright MYSOs associated with the most massive clumps, probably due to very short pre-main-sequence lifetimes in the most luminous sources.

  17. Magnetic fields and massive star formation

    SciTech Connect

    Zhang, Qizhou; Keto, Eric; Ho, Paul T. P.; Ching, Tao-Chung; Chen, How-Huan; Qiu, Keping; Girart, Josep M.; Juárez, Carmen; Liu, Hauyu; Tang, Ya-Wen; Koch, Patrick M.; Rao, Ramprasad; Lai, Shih-Ping; Li, Zhi-Yun; Frau, Pau; Li, Hua-Bai; Padovani, Marco; Bontemps, Sylvain

    2014-09-10

    Massive stars (M > 8 M {sub ☉}) typically form in parsec-scale molecular clumps that collapse and fragment, leading to the birth of a cluster of stellar objects. We investigate the role of magnetic fields in this process through dust polarization at 870 μm obtained with the Submillimeter Array (SMA). The SMA observations reveal polarization at scales of ≲0.1 pc. The polarization pattern in these objects ranges from ordered hour-glass configurations to more chaotic distributions. By comparing the SMA data with the single dish data at parsec scales, we found that magnetic fields at dense core scales are either aligned within 40° of or perpendicular to the parsec-scale magnetic fields. This finding indicates that magnetic fields play an important role during the collapse and fragmentation of massive molecular clumps and the formation of dense cores. We further compare magnetic fields in dense cores with the major axis of molecular outflows. Despite a limited number of outflows, we found that the outflow axis appears to be randomly oriented with respect to the magnetic field in the core. This result suggests that at the scale of accretion disks (≲ 10{sup 3} AU), angular momentum and dynamic interactions possibly due to close binary or multiple systems dominate over magnetic fields. With this unprecedentedly large sample of massive clumps, we argue on a statistical basis that magnetic fields play an important role during the formation of dense cores at spatial scales of 0.01-0.1 pc in the context of massive star and cluster star formation.

  18. Phenomenology in minimal theory of massive gravity

    NASA Astrophysics Data System (ADS)

    De Felice, Antonio; Mukohyama, Shinji

    2016-04-01

    We investigate the minimal theory of massive gravity (MTMG) recently introduced. After reviewing the original construction based on its Hamiltonian in the vielbein formalism, we reformulate it in terms of its Lagrangian in both the vielbein and the metric formalisms. It then becomes obvious that, unlike previous attempts in the literature of Lorentz-violating massive gravity, not only the potential but also the kinetic structure of the action is modified from the de Rham-Gabadadze-Tolley (dRGT) massive gravity theory. We confirm that the number of physical degrees of freedom in MTMG is two at fully nonlinear level. This proves the absence of various possible pathologies such as superluminality, acausality and strong coupling. Afterwards, we discuss the phenomenology of MTMG in the presence of a dust fluid. We find that on a flat homogeneous and isotropic background we have two branches. One of them (self-accelerating branch) naturally leads to acceleration without the genuine cosmological constant or dark energy. For this branch both the scalar and the vector modes behave exactly as in general relativity (GR). The phenomenology of this branch differs from GR in the tensor modes sector, as the tensor modes acquire a non-zero mass. Hence, MTMG serves as a stable nonlinear completion of the self-accelerating cosmological solution found originally in dRGT theory. The other branch (normal branch) has a dynamics which depends on the time-dependent fiducial metric. For the normal branch, the scalar mode sector, even though as in GR only one scalar mode is present (due to the dust fluid), differs from the one in GR, and, in general, structure formation will follow a different phenomenology. The tensor modes will be massive, whereas the vector modes, for both branches, will have the same phenomenology as in GR.

  19. Surgical embolectomy for acute massive pulmonary embolism

    PubMed Central

    Yavuz, Senol; Toktas, Faruk; Goncu, Tugrul; Eris, Cuneyt; Gucu, Arif; Ay, Derih; Erdolu, Burak; Tenekecioglu, Erhan; Karaagac, Kemal; Vural, Hakan; Ozyazicioglu, Ahmet

    2014-01-01

    Objective: Acute massive pulmonary embolism (PE) is associated with significant mortality rate despite diagnostic and therapeutic advances. The aim of this study was to analyze our clinical outcomes of patients with acute massive PE who underwent emergency surgical pulmonary embolectomy. Methods: This retrospective study included 13 consecutive patients undergoing emergency surgical pulmonary embolectomy for acute massive PE at our institution from March 2000 to November 2013. The medical records of all patients were reviewed for demograhic and preoperative data and postoperative outcomes. All patients presented with cardiogenic shock with severe right ventricular dysfunction confirmed by echocardiography, where 4 (30.8%) of the patients experienced cardiac arrest requiring cardiopulmonary resuscitation before surgery. Results: The mean age of patients was 61.8 ± 14 years (range, 38 to 82 years) with 8 (61.5%) males. The most common risk factors for PE was the history of prior deep venous thrombosis (n = 9, 69.2%). There were 3 (23.1%) in-hospital deaths including operative mortality of 7.7% (n = 1). Ten (76.9%) patients survived and were discharged from the hospital. The mean follow-up was 25 months; follow-up was 100% complete in surviving patients. There was one case (7.7%) of late death 12 months after surgery due to renal carcinoma. Postoperative echocardiographic pressure measurements demonstrated a significant reduction (P < 0.001). At final follow-up, all patients were in New York Heart Association class I and no readmission for a recurrent of PE was observed. Conclusion: Surgical pulmonary embolectomy is a reasonable option and could be performed with acceptable results, if it is performed early in patients with acute massive PE who have not reached the profound cardiogenic shock or cardiac arrest. PMID:25664045

  20. f(R) Cosmology and Massive Neutrinos

    NASA Astrophysics Data System (ADS)

    Motohashi, Hayato; Starobinsky, Alexei A.; Yokoyama, Jun'ichi

    2012-02-01

    f(R) gravity provides viable cosmology alternative to the ΛCDM model. We discuss the effect of massive neutrinos on matter power spectrum in this theory, to show that the anomalous growth of density fluctuations on small scales due to the scalaron force can be compensated by free streaming of neutrinos. As a result, models which predict observable deviation of the equation-of-state parameter wDE from wDE = -1 may be reconciled with observations of matter clustering if the total neutrino mass is O(0.5 eV).

  1. Holographically viable extensions of topologically massive and minimal massive gravity?

    NASA Astrophysics Data System (ADS)

    Altas, Emel; Tekin, Bayram

    2016-01-01

    Recently [E. Bergshoeff et al., Classical Quantum Gravity 31, 145008 (2014)], an extension of the topologically massive gravity (TMG) in 2 +1 dimensions, dubbed as minimal massive gravity (MMG), which is free of the bulk-boundary unitarity clash that inflicts the former theory and all the other known three-dimensional theories, was found. Field equations of MMG differ from those of TMG at quadratic terms in the curvature that do not come from the variation of an action depending on the metric alone. Here we show that MMG is a unique theory and there does not exist a deformation of TMG or MMG at the cubic and quartic order (and beyond) in the curvature that is consistent at the level of the field equations. The only extension of TMG with the desired bulk and boundary properties having a single massive degree of freedom is MMG.

  2. GRBs as Probes of Massive Stars Near and Far

    NASA Astrophysics Data System (ADS)

    Fynbo, Johan P. U.; Malesani, Daniele

    2008-06-01

    Long-duration gamma-ray bursts are the manifestations of massive stellar death. Due to the immense energy release they are detectable from most of the observable universe. In this way they allow us to study the deaths of single (or binary) massive stars possibly throughout the full timespan massive stars have existed in the Universe. GRBs provide a means to infer information about the environments and typical galaxies in which massive stars are formed. Two main obstacles remain to be crossed before the full potential of GRBs as probes of massive stars can be harvested: i) we need to build more complete and well understood samples in order not to be fooled by biases, and ii) we need to understand to which extent GRBs may be intrinsically biased in the sense that they are only formed by a limited subset of massive stars defined by most likely a restricted metallicity interval. I describe the status of an ongoing effort to build a more complete sample of long-duration GRBs with measured redshifts. Already now we can conclude that the environments of GRB progenitors are very diverse with metallicities ranging from solar to a hundredth solar and extinction ranging from none to AV > 5 mag. We have also identified a sightline with significant escape of Lyman continuum photons and another with a clear 2175 Å extinction bump.

  3. Positive signs in massive gravity

    NASA Astrophysics Data System (ADS)

    Cheung, Clifford; Remmen, Grant N.

    2016-04-01

    We derive new constraints on massive gravity from unitarity and analyticity of scattering amplitudes. Our results apply to a general effective theory defined by Einstein gravity plus the leading soft diffeomorphism-breaking corrections. We calculate scattering amplitudes for all combinations of tensor, vector, and scalar polarizations. The high-energy behavior of these amplitudes prescribes a specific choice of couplings that ameliorates the ultraviolet cutoff, in agreement with existing literature. We then derive consistency conditions from analytic dispersion relations, which dictate positivity of certain combinations of parameters appearing in the forward scattering amplitudes. These constraints exclude all but a small island in the parameter space of ghost-free massive gravity. While the theory of the "Galileon" scalar mode alone is known to be inconsistent with positivity constraints, this is remedied in the full massive gravity theory.

  4. Population synthesis of massive stars

    NASA Astrophysics Data System (ADS)

    Vanbeveren, Dany

    2014-09-01

    This review deals with massive star population synthesis with a realistic population of binaries. We focus on the comparison between observed star numbers (as a function of metallicity) and theoretically predicted numbers of stellar populations in regions of continuous star formation and in starburst regions. Special attention is given to the O-type/WR/red supergiant stellar population, the population of blue supergiants, the pulsar and binary pulsar population, and the supernova rates. Finally, we consider massive double compact star mergers and the link with gravitational wave sources (the advanced LIGO II) and r-process element production sites.

  5. Sedeonic Equations of Massive Fields

    NASA Astrophysics Data System (ADS)

    Mironov, Sergey V.; Mironov, Victor L.

    2015-01-01

    Prior work on space-time sedeon algebra models relativistic quantum mechanical equation of motion with corresponding field equations, mediated by massive or massless spin-1 or spin-1/2 particles. In the massless spin-1 case, such exchange particles mediate fields in analogy to Maxwell's equations in Lorentz gauge. This paper demonstrates fundamental aspects of massive field's theory, such as gauge invariance, charge conservation, Poynting's theorem, potential of a stationary scalar point source, plane wave solution, and interaction between point sources. We briefly discuss some aspects of sedeonic algebra and their potential physical applications.

  6. Massive Gravitons on Bohmian Congruences

    NASA Astrophysics Data System (ADS)

    Fathi, Mohsen; Mohseni, Morteza

    2016-08-01

    Taking a quantum corrected form of Raychaudhuri equation in a geometric background described by a Lorentz-violating massive theory of gravity, we go through investigating a time-like congruence of massive gravitons affected by a Bohmian quantum potential. We find some definite conditions upon which these gravitons are confined to diverging Bohmian trajectories. The respective behaviour of those quantum potentials are also derived and discussed. Additionally, and through a relativistic quantum treatment of a typical wave function, we demonstrate schematic conditions on the associated frequency to the gravitons, in order to satisfy the necessity of divergence.

  7. Understanding massively open online courses.

    PubMed

    Billings, Diane M

    2014-02-01

    Massively open online courses (MOOCs) are an innovative delivery system for educational offerings. MOOCs have been hailed with optimism for making education accessible to many, but at the same time, they have been criticized for poor participant completion rates. Nurse educators are considering whether and how to use MOOCs; this column explains MOOCs and their advantages and disadvantages for nurse educators. PMID:24494660

  8. Massively parallel visualization: Parallel rendering

    SciTech Connect

    Hansen, C.D.; Krogh, M.; White, W.

    1995-12-01

    This paper presents rendering algorithms, developed for massively parallel processors (MPPs), for polygonal, spheres, and volumetric data. The polygon algorithm uses a data parallel approach whereas the sphere and volume renderer use a MIMD approach. Implementations for these algorithms are presented for the Thinking Machines Corporation CM-5 MPP.

  9. Mass loss of massive stars

    NASA Astrophysics Data System (ADS)

    Martins, F.

    2015-12-01

    In this contribution we review the properties of the winds of massive stars. We focus on OB stars, red supergiants, Luminous Blue Variables (LBVs) and Wolf-Rayet stars. For each type of star, we summarize the main wind properties and we give a brief description of the physical mechanism(s) responsible for mass loss.

  10. Dark matter in massive galaxies

    NASA Astrophysics Data System (ADS)

    Gerhard, Ortwin

    2013-07-01

    The spatial distributions of luminous and dark matter in massive early-type galaxies (ETGs) reflect the formation processes which shaped these systems. This article reviews the predictions of cosmological simulations for the dark and baryonic components of ETGs, and the observational constraints from lensing, hydrostatic X-ray gas atmospheres, and outer halo stellar dynamics.

  11. Sinus histiocytosis with massive lymphadenopathy

    SciTech Connect

    Pastakia, B.; Weiss, S.H.

    1987-11-01

    Gallium uptake corresponding to the extent of the disease in a patient with histologically proven sinus histiocytosis with massive lymphadenopathy (SHML) is reported. Computerized tomography confirmed the presence of bilateral retrobulbar masses, involvement of both lateral recti, erosion of the bony orbital floor with encroachment of tumor into the right maxillary antrum, and retropharyngeal involvement.

  12. A Study on the Pedagogical Components of Massive Online Courses

    ERIC Educational Resources Information Center

    Raposo-Rivas, Manuela; Martínez-Figueira, Esther; Campos, Jose Antonio Sarmiento

    2015-01-01

    At the end of the first decade of the 21st century, the rapid growth in the MOOCs offering brought about a new educational landscape, posing new challenges to teaching and learning, mainly due to massive participation, ubiquity and free enrollment. These courses embody a confluence of technological and pedagogical mediations yet to be fully…

  13. QUARK MATTER IN MASSIVE COMPACT STARS

    SciTech Connect

    Weissenborn, Simon; Pagliara, Giuseppe; Schaffner-Bielich, Juergen; Sagert, Irina; Hempel, Matthias

    2011-10-10

    The recent observation of the pulsar PSR J1614-2230 with a mass of 1.97 {+-} 0.04 M{sub sun} gives a strong constraint on the quark and nuclear matter equations of state (EoS). We explore the parameter ranges for a parameterized EoS for quark stars. We find that strange stars, made of absolutely stable strange quark matter, comply with the new constraint only if effects from the strong coupling constant and color-superconductivity are taken into account. Hybrid stars, compact stars with a quark matter core and a hadronic outer layer, can be as massive as 2 M{sub sun}, but only for a significantly limited range of parameters. We demonstrate that the appearance of quark matter in massive stars crucially depends on the stiffness of the nuclear matter EoS. We show that the masses of hybrid stars stay below the ones of hadronic and pure quark stars, due to the softening of the EoS at the quark-hadron phase transition.

  14. Two cases of asymptomatic massive fetomaternal hemorrhage.

    PubMed

    Peedin, Alexis R; Mazepa, Marshall A; Park, Yara A; Weimer, Eric T; Schmitz, John L; Raval, Jay S

    2015-04-01

    Evaluation of fetomaternal hemorrhage (FMH) in the immediate postpartum period is critical for the timely administration of Rh immunoglobulin (RhIG) prophylaxis to minimize the risk of alloimmunization in D-negative mothers of D-positive newborns. We report a series of two clinically-unsuspected cases of massive FMHs identified at our university medical center. Retrospective records of two cases of massive FMH were investigated using the electronic medical record. After positive fetal bleed screens, flow cytometric analysis for hemoglobin F was performed to quantify the volume of the hemorrhages in both cases. Flow cytometric enumeration with anti-D was also performed in one case. The two patients had 209.5 and 75 mL of fetal blood in circulation, resulting in 8 and 4 doses of RhIG administered, respectively. For the former patient, flow cytometric analysis with anti-D ruled out hereditary persistence of fetal hemoglobin and supported the fetal origin of the red cells. Due to the clinically-silent nature of both hemorrhages, further evaluation of the newborns' blood was not performed. These cases highlight the importance of rapidly obtaining accurate measurements of fetal blood loss via flow cytometric analysis in cases of FMH, particularly in clinically-unsuspected cases, to ensure timely administration of adequate immunoprophylaxis to D-negative mothers. PMID:25736586

  15. No Massive Elementary Bosons Exist in Nature

    NASA Astrophysics Data System (ADS)

    Morabito, D. L.; Fujita, S.; Godoy, S.

    1998-04-01

    Elementary particles are defined such that (a) elementary particles are indistinguishable (indistinguishability) and (b) particles can combine, in arbitrary high number, to form a composite. The resulting composite must be either a boson or a fermion (elementarity). The quantum statistics of a composite particle will be studied by looking at the center-of-mass motion. We postulate that the center-of-mass moves following general principles of quantum theory and special relativity. We show that two-identical-boson composites such as π-π are forbidden due to the fact that no center-of-mass states of definite statistics can be constructed. This means that there can be no massive elementary bosons in nature, which is in accord with Dirac's conclusion: there are only half-spin elementary fermions in nature. Experiments show that photons move as bosons. But photons are massless and always travel with the light speed in vacuum. They do not possess position observables and cannot form composites. Composites of two different bosons such as π-K are shown to move as fermions, which violates the spin-statistics theorem. We reject two-different-boson composites since the spin-statistics theorem should hold for the center-of-mass motion. Known massive bosons such as π, K, W, Z, ldots must be regarded as composites. Besides, they cannot form composites among them.

  16. Translation invariant time-dependent solutions to massive gravity

    SciTech Connect

    Mourad, J.; Steer, D.A. E-mail: steer@apc.univ-paris7.fr

    2013-12-01

    Homogeneous time-dependent solutions of massive gravity generalise the plane wave solutions of the linearised Fierz-Pauli equations for a massive spin-two particle, as well as the Kasner solutions of General Relativity. We show that they also allow a clear counting of the degrees of freedom and represent a simplified framework to work out the constraints, the equations of motion and the initial value formulation. We work in the vielbein formulation of massive gravity, find the phase space resulting from the constraints and show that several disconnected sectors of solutions exist some of which are unstable. The initial values determine the sector to which a solution belongs. Classically, the theory is not pathological but quantum mechanically the theory may suffer from instabilities. The latter are not due to an extra ghost-like degree of freedom.

  17. Chiral description of massive gravity

    NASA Astrophysics Data System (ADS)

    Alexandrov, Sergei; Krasnov, Kirill; Speziale, Simone

    2013-06-01

    We propose and study a new first order version of the ghost-free massive gravity. Instead of metrics or tetrads, it uses a connection together with Plebanski's chiral 2-forms as fundamental variables, rendering the phase space structure similar to that of SU(2) gauge theories. The chiral description simplifies computations of the constraint algebra, and allows us to perform the complete canonical analysis of the system. In particular, we explicitly compute the secondary constraint and carry out the stabilization procedure, thus proving that in general the theory propagates 7 degrees of freedom, consistently with previous claims. Finally, we point out that the description in terms of 2-forms opens the door to an infinite class of ghost-free massive bi-gravity actions. Our results apply directly to Euclidean signature. The reality conditions to be imposed in the Lorentzian signature appear to be more complicated than in the usual gravity case and are left as an open issue.

  18. Massive gravity on a brane

    SciTech Connect

    Chacko, Z.; Graesser, M.L.; Grojean, C.; Pilo, L.

    2003-12-11

    At present no theory of a massive graviton is known that is consistent with experiments at both long and short distances. The problem is that consistency with long distance experiments requires the graviton mass to be very small. Such a small graviton mass however implies an ultraviolet cutoff for the theory at length scales far larger than the millimeter scale at which gravity has already been measured. In this paper we attempt to construct a model which avoids this problem. We consider a brane world setup in warped AdS spacetime and we investigate the consequences of writing a mass term for the graviton on a the infrared brane where the local cutoff is of order a large (galactic) distance scale. The advantage of this setup is that the low cutoff for physics on the infrared brane does not significantly affect the predictivity of the theory for observers localized on the ultraviolet brane. For such observers the predictions of this theory agree with general relativity at distances smaller than the infrared scale but go over to those of a theory of massive gravity at longer distances. A careful analysis of the graviton two-point function, however, reveals the presence of a ghost in the low energy spectrum. A mode decomposition of the higher dimensional theory reveals that the ghost corresponds to the radion field. We also investigate the theory with a brane localized mass for the graviton on the ultraviolet brane, and show that the physics of this case is similar to that of a conventional four dimensional theory with a massive graviton, but with one important difference: when the infrared brane decouples and the would-be massive graviton gets heavier than the regular Kaluza-Klein modes, it becomes unstable and it has a finite width to decay off the brane into the continuum of Kaluza-Klein states.

  19. Efficient, massively parallel eigenvalue computation

    NASA Technical Reports Server (NTRS)

    Huo, Yan; Schreiber, Robert

    1993-01-01

    In numerical simulations of disordered electronic systems, one of the most common approaches is to diagonalize random Hamiltonian matrices and to study the eigenvalues and eigenfunctions of a single electron in the presence of a random potential. An effort to implement a matrix diagonalization routine for real symmetric dense matrices on massively parallel SIMD computers, the Maspar MP-1 and MP-2 systems, is described. Results of numerical tests and timings are also presented.

  20. Cosmological stability bound in massive gravity and bigravity

    SciTech Connect

    Fasiello, Matteo; Tolley, Andrew J. E-mail: andrew.j.tolley@case.edu

    2013-12-01

    We give a simple derivation of a cosmological bound on the graviton mass for spatially flat FRW solutions in massive gravity with an FRW reference metric and for bigravity theories. This bound comes from the requirement that the kinetic term of the helicity zero mode of the graviton is positive definite. The bound is dependent only on the parameters in the massive gravity potential and the Hubble expansion rate for the two metrics. We derive the decoupling limit of bigravity and FRW massive gravity, and use this to give an independent derivation of the cosmological bound. We recover our previous results that the tension between satisfying the Friedmann equation and the cosmological bound is sufficient to rule out all observationally relevant FRW solutions for massive gravity with an FRW reference metric. In contrast, in bigravity this tension is resolved due to different nature of the Vainshtein mechanism. We find that in bigravity theories there exists an FRW solution with late-time self-acceleration for which the kinetic terms for the helicity-2, helicity-1 and helicity-0 are generically nonzero and positive making this a compelling candidate for a model of cosmic acceleration. We confirm that the generalized bound is saturated for the candidate partially massless (bi)gravity theories but the existence of helicity-1/helicity-0 interactions implies the absence of the conjectured partially massless symmetry for both massive gravity and bigravity.

  1. Extinction in young massive clusters

    NASA Astrophysics Data System (ADS)

    De Marchi, Guido; Panagia, Nino

    2016-01-01

    Up to ages of ~100 Myr, massive clusters are still swamped in large amounts of gas and dust, causing considerable and uneven levels of extinction. At the same time, large grains (ices?) produced by type II supernovae profoundly alter the interstellar medium (ISM), thus resulting in extinction properties very different from those of the diffuse ISM. To obtain physically meaningful parameters of stars (luminosities, effective temperatures, masses, ages, etc.) we must understand and measure the local extinction law. We have developed a powerful method to unambiguously determine the extinction law everywhere across a cluster field, using multi-band photometry of red giant stars belonging to the red clump (RC) and are applying it to young massive clusters in the Local Group. In the Large Magellanic Cloud, with about 20 RC stars per arcmin2, for each field we can easily derive an accurate extinction curve over the entire wavelength range of the photometry. As an example, we present the extinction law of the Tarantula nebula (30 Dor) based on thousands of stars observed as part of the Hubble Tarantula Treasury Project. We discuss how the incautious adoption of the Milky Way extinction law in the analysis of massive star forming regions may lead to serious underestimates of the fluxes and of the star formation rates by factors of 2 or more.

  2. Analytics for Massive Heat Maps

    SciTech Connect

    Bohn, Shawn J.; Payne, Deborah A.; Nakamura, Grant C.; Love, Douglas V.

    2009-01-19

    High throughput instrumentation for genomics is producing data orders of magnitude greater than even a decade before. Biologists often visualize the data of these experiments through the use of heat maps. For large datasets, heat map visualizations do not scale. These visualizations are only capable of displaying a portion of the data, making it difficult for scientists to find and detect patterns that span more than a subsection of the data. We present a novel method that provides an interactive visual display for massive heat maps [O(108)]. Our process shows how a massive heat map can be decomposed into multiple levels of abstraction to represent the underlying macrostructures. We aggregate these abstractions into a framework that can allow real-time navigation of the space. To further assist pattern discovery, we ground our system on the principle of focus+context. Our framework also addresses the issue of balancing the memory and display resolution and heat map size. We will show that this technique for biologists provides a powerful new visual metaphor for analyzing massive datasets.

  3. Massive photon and dark energy

    NASA Astrophysics Data System (ADS)

    Kouwn, Seyen; Oh, Phillial; Park, Chan-Gyung

    2016-04-01

    We investigate the cosmology of massive electrodynamics and explore the possibility whether the massive photon could provide an explanation of dark energy. The action is given by the scalar-vector-tensor theory of gravity, which is obtained by nonminimal coupling of the massive Stueckelberg QED with gravity; its cosmological consequences are studied by paying particular attention to the role of photon mass. We find that the theory allows for cosmological evolution where the radiation- and matter-dominated epochs are followed by a long period of virtually constant dark energy that closely mimics a Λ CDM model. We also find that the main source of the current acceleration is provided by the nonvanishing photon mass governed by the relation Λ ˜m2 . A detailed numerical analysis shows that the nonvanishing photon mass on the order of ˜1 0-34 eV is consistent with current observations. This magnitude is far less than the most stringent limit on the photon mass available so far, which is on the order of m ≤1 0-27 eV .

  4. Analytics for massive heat maps

    NASA Astrophysics Data System (ADS)

    Bohn, Shawn J.; Payne, Deborah; Nakamura, Grant; Love, Douglass

    2009-01-01

    High throughput instrumentation for genomics is producing data orders of magnitude greater than even a decade before. Biologists often visualize the data of these experiments through the use of heat maps. For large datasets, heat map visualizations do not scale. These visualizations are only capable of displaying a portion of the data, making it difficult for scientists to find and detect patterns that span more than a subsection of the data. We present a novel method that provides an interactive visual display for massive heat maps [O(108)]. Our process shows how a massive heat map can be decomposed into multiple levels of abstraction to represent the underlying macrostructures. We aggregate these abstractions into a framework that can allow near real-time navigation of the space. To further assist pattern discovery, we ground our system on the principle of focus+context. Our framework also addresses the issue of balancing the memory and display resolution and heat map size. We will show that this technique for biologists provides a powerful new visual metaphor for analyzing massive datasets.

  5. Massive pre-placental and subchorionic haematoma.

    PubMed

    Loi, K; Tan, K T

    2006-12-01

    We report an unusual case of massive pre-placental and subchorionic haematoma occurring in a 26-year-old woman who presented with antepartum haemorrhage at 24 weeks gestation. Ultrasonography showed a subchorionic haematoma in the lower posterior uterine wall measuring 5.0 cm in largest diameter. There was also a separate irregular multiloculated structure measuring 4.3 cm in largest diameter on the surface of the placenta, due to a pre-placental haematoma. The subchorionic haematoma diminished in size over time, while the pre-placental haematoma continued to grow, measuring 9.0 cm at 28 weeks, and 9.3 cm at 32 weeks. At 32 weeks, the patient presented with premature rupture of membranes and four days later, an emergency caesarean section was performed when the patient had another episode of severe antepartum haemorrhage. Both mother and child recovered well. The current literature on such haematomas is reviewed. PMID:17139407

  6. Modification of gravity due to torsion

    SciTech Connect

    Nair, V. P.; Nikiforova, V.; Randjbar-Daemi, S.; Rubakov, V.

    2010-01-01

    Modifications of general relativity have been considered as one of the possible ways of addressing some of the outstanding problems related to the large scale gravitational physics. In this contribution we review some of the recent results which are due to the inclusion of dynamical torsion. More specifically we shall discuss the propagation of massive spin-2 particles in flat and curved space times. We shall show that, contrary to what is generally believed, spinning matter is not the sole source of torsion field. A symmetric energy momentum tensor can also couple to torsion degrees of freedom. The massive and massless spin-2 particles mix giving rise to an infrared modification of gravity.

  7. Pancreatic Aetiology for Massive Upper Gastrointestinal Haemorrhage in Pregnancy

    PubMed Central

    Zaborowski, Alexandra; Walsh, Siun M.; Ravi, Narayanasamy; Reynolds, John V.

    2016-01-01

    We present herein what we believe is the first reported case of massive upper gastrointestinal bleeding in pregnancy due to a pancreatic neuroendocrine tumour causing left sided portal hypertension. A 37-year-old 27-week pregnant female presented with massive haematemesis and melaena requiring transfusion of 10 units of red cell concentrate. Gastric varices were evident at endoscopy. An MRI revealed a large mass infiltrating the pancreatic tail and spleen with massive upper abdominal varix formation secondary to splenic vein invasion. A caesarean section was performed, followed by a radical en bloc partial pancreatectomy and splenectomy with resection of the fundus of the stomach and ligation of gastric and splenic varices. Her postoperative course was uncomplicated. Histology revealed a well differentiated grade 2 neuroendocrine tumour with final staging of T4N0. This case highlights an infrequently encountered cause of massive gastrointestinal bleeding. Diagnosis and management of pancreatic neuroendocrine tumours, due to their rarity and variable clinical presentation, can be challenging particularly in the setting of pregnancy where the wellbeing of a second patient must also be considered. A multidisciplinary approach with input from obstetricians and general surgeons is required when deciding optimum management, while also taking into account the patient's preferences. PMID:27034880

  8. Pancreatic Aetiology for Massive Upper Gastrointestinal Haemorrhage in Pregnancy.

    PubMed

    Zaborowski, Alexandra; Walsh, Siun M; Ravi, Narayanasamy; Reynolds, John V

    2016-01-01

    We present herein what we believe is the first reported case of massive upper gastrointestinal bleeding in pregnancy due to a pancreatic neuroendocrine tumour causing left sided portal hypertension. A 37-year-old 27-week pregnant female presented with massive haematemesis and melaena requiring transfusion of 10 units of red cell concentrate. Gastric varices were evident at endoscopy. An MRI revealed a large mass infiltrating the pancreatic tail and spleen with massive upper abdominal varix formation secondary to splenic vein invasion. A caesarean section was performed, followed by a radical en bloc partial pancreatectomy and splenectomy with resection of the fundus of the stomach and ligation of gastric and splenic varices. Her postoperative course was uncomplicated. Histology revealed a well differentiated grade 2 neuroendocrine tumour with final staging of T4N0. This case highlights an infrequently encountered cause of massive gastrointestinal bleeding. Diagnosis and management of pancreatic neuroendocrine tumours, due to their rarity and variable clinical presentation, can be challenging particularly in the setting of pregnancy where the wellbeing of a second patient must also be considered. A multidisciplinary approach with input from obstetricians and general surgeons is required when deciding optimum management, while also taking into account the patient's preferences. PMID:27034880

  9. Cosmological perturbations in massive bigravity

    SciTech Connect

    Lagos, Macarena; Ferreira, Pedro G. E-mail: p.ferreira1@physics.ox.ac.uk

    2014-12-01

    We present a comprehensive analysis of classical scalar, vector and tensor cosmological perturbations in ghost-free massive bigravity. In particular, we find the full evolution equations and analytical solutions in a wide range of regimes. We show that there are viable cosmological backgrounds but, as has been found in the literature, these models generally have exponential instabilities in linear perturbation theory. However, it is possible to find stable scalar cosmological perturbations for a very particular choice of parameters. For this stable subclass of models we find that vector and tensor perturbations have growing solutions. We argue that special initial conditions are needed for tensor modes in order to have a viable model.

  10. Spontaneous Scalarization of Massive Fields

    NASA Astrophysics Data System (ADS)

    Ramazanoglu, Fethi M.; Pretorius, Frans

    2014-03-01

    Spontaneous scalarization is a phenomenon in certain scalar-tensor theories where large deviations from general relativity can be observed inside compact stars, while the known observational bounds can also be satisfied far away. This scenario has been investigated for massless scalars and binary neutron stars using numerical relativity, but the parameter space for such theories have been severely restricted by recent observations. Here, we present our results on the spontaneous scalarization of massive scalars. We simulate cases with different equations of state and scalar field parameters, and comment on the detectability of the scalar field effects from the gravitational wave signal.

  11. Detecting weakly interacting massive particles.

    NASA Astrophysics Data System (ADS)

    Drukier, A. K.; Gelmini, G. B.

    The growing synergy between astrophysics, particle physics, and low background experiments strengthens the possibility of detecting astrophysical non-baryonic matter. The idea of direct detection is that an incident, massive weakly interacting particle could collide with a nucleus and transfer an energy that could be measured. The present low levels of background achieved by the PNL/USC Ge detector represent a new technology which yields interesting bounds on Galactic cold dark matter and on light bosons emitted from the Sun. Further improvements require the development of cryogenic detectors. The authors analyse the practicality of such detectors, their optimalization and background suppression using the "annual modulation effect".

  12. Quantum aspects of massive gravity

    NASA Astrophysics Data System (ADS)

    Park, Minjoon

    2011-05-01

    We consider the effect of quantum interactions on Pauli-Fierz massive gravity. With generic graviton cubic interactions, we observe that the 1-loop counterterms do not conform to the tree level structure of Pauli-Fierz action, resulting in the reappearance of the sixth mode ghost. Then to explore the quantum effects to the full extent, we calculate the resummed graviton propagator with an arbitrary interaction and analyze its complete structure, from which a minimal condition for the absence of the ghost is obtained.

  13. Solid holography and massive gravity

    NASA Astrophysics Data System (ADS)

    Alberte, Lasma; Baggioli, Matteo; Khmelnitsky, Andrei; Pujolàs, Oriol

    2016-02-01

    Momentum dissipation is an important ingredient in condensed matter physics that requires a translation breaking sector. In the bottom-up gauge/gravity duality, this implies that the gravity dual is massive. We start here a systematic analysis of holographic massive gravity (HMG) theories, which admit field theory dual interpretations and which, therefore, might store interesting condensed matter applications. We show that there are many phases of HMG that are fully consistent effective field theories and which have been left overlooked in the literature. The most important distinction between the different HMG phases is that they can be clearly separated into solids and fluids. This can be done both at the level of the unbroken spacetime symmetries as well as concerning the elastic properties of the dual materials. We extract the modulus of rigidity of the solid HMG black brane solutions and show how it relates to the graviton mass term. We also consider the implications of the different HMGs on the electric response. We show that the types of response that can be consistently described within this framework is much wider than what is captured by the narrow class of models mostly considered so far.

  14. [Treatment alternatives in massive hemorrhage].

    PubMed

    Fernández-Hinojosa, E; Murillo-Cabezas, F; Puppo-Moreno, A; Leal-Noval, S R

    2012-10-01

    Massive hemorrhage is the main cause of mortality and morbidity in trauma patients, and is one of the most important causes in any patient following major surgery. Conventional treatment consists of volume replacement, including the transfusion of blood products, so that tissue perfusion and oxygenation may be maintained. Associated hypothermia, acidosis and coagulopathy is a lethal triad. This review focuses on the latest therapeutic management of massive hemorrhage. The authors advocate the use of crystalloids as per protocol (controlled volumes) in order to achieve a systolic blood pressure of 85mmHg. The administration of the three blood products (red cells, plasma, and platelets) should be on a 1:1:1 basis. Where possible, this in turn should be guided by thromboelastography performed at point of care near the patient. Coagulopathy can occur early and late. With the exception of tranexamic acid, the cost-benefit relationships of the hemostatic agents, such as fibrinogen, prothrombin complex, and recombinant F VII, are subject to discussion. PMID:22321860

  15. DETECTING MASSIVE GRAVITONS USING PULSAR TIMING ARRAYS

    SciTech Connect

    Lee, Kejia; Kramer, Michael; Jenet, Fredrick A.; Price, Richard H.; Wex, Norbert

    2010-10-20

    At the limit of weak static fields, general relativity becomes Newtonian gravity with a potential field that falls off as inverse distance rather than a theory of Yukawa-type fields with a finite range. General relativity also predicts that the speed of disturbances of its waves is c, the vacuum light speed, and is non-dispersive. For these reasons, the graviton, the boson for general relativity, can be considered to be massless. Massive gravitons, however, are features of some alternatives to general relativity. This has motivated experiments and observations that, so far, have been consistent with the zero-mass graviton of general relativity, but further tests will be valuable. A basis for new tests may be the high sensitivity gravitational wave (GW) experiments that are now being performed and the higher sensitivity experiments that are being planned. In these experiments, it should be feasible to detect low levels of dispersion due to non-zero graviton mass. One of the most promising techniques for such a detection may be the pulsar timing program that is sensitive to nano-Hertz GWs. Here, we present some details of such a detection scheme. The pulsar timing response to a GW background with the massive graviton is calculated, and the algorithm to detect the massive graviton is presented. We conclude that, with 90% probability, massless gravitons can be distinguished from gravitons heavier than 3 x 10{sup -22} eV (Compton wavelength {lambda}{sub g} = 4.1 x 10{sup 12} km), if bi-weekly observation of 60 pulsars is performed for 5 years with a pulsar rms timing accuracy of 100 ns. If 60 pulsars are observed for 10 years with the same accuracy, the detectable graviton mass is reduced to 5 x 10{sup -23} eV ({lambda}{sub g} = 2.5 x 10{sup 13} km); for 5 year observations of 100 or 300 pulsars, the sensitivity is respectively 2.5 x 10{sup -22} ({lambda}{sub g} = 5.0 x 10{sup 12} km) and 10{sup -22} eV ({lambda}{sub g} = 1.2 x 10{sup 13} km). Finally, a 10 year

  16. Massive Compact Stars as Quark Stars

    NASA Astrophysics Data System (ADS)

    Rodrigues, Hilário; Barbosa Duarte, Sérgio; de Oliveira, José Carlos T.

    2011-03-01

    High-mass compact stars have been reported recently in the literature, providing strong constraints on the properties of the ultra dense matter beyond the saturation nuclear density. In view of these results, the calculations of quark star or hybrid star equilibrium structure must be compatible with the provided observational data. But since the equations of state used in describing quark matter are in general too soft in comparison with the equation of states used to describe the hadronic or nuclear matter, the calculated quark star models presented in the literature are in general not suitable to explain the stability of highly-compact massive objects. In this work, we present the calculations of a spherically symmetric quark star structure by using an equation of state that takes into account the superconducting color-flavor locked phase of the strange quark matter. In addition, some fundamental aspects of QCD (asymptotic freedom and confinement) are considered by means of a phenomenological description of the deconfined quark phase, the density-dependent quark mass model. The quark matter behavior introduced by this model stiffens the corresponding equation of state. We thus investigate the influence of this model on the mass-radius diagram of quark stars. We obtain massive quark stars due to the stiffness of the equation of state, when a reasonable parameterization of the color superconducting gap is used. Models of quark stars enveloped by a nucleonic crust composed of a nuclear lattice embedded in an electron gas, with nuclei close to neutron drip line, are also discussed.

  17. Sinus histiocytosis with massive lymphadenopathy: a "massive" misnomer.

    PubMed

    Sardana, Divesh; Goyal, Ashima; Gauba, Krishan

    2015-04-01

    Sinus histiocytosis with massive lymphadenopathy also known as Rosai-Dorfman disease is a rare, benign, histiocytic disorder of unknown origin characterized by lymphadenopathy. Since its original description by Rosai and Dorfman in 1969, small number of cases has been reported; hence no specific diagnostic criteria and treatment guidelines have been suggested. The purpose of this article is to present and discuss a case of Rosai Dorfman Syndrome in 4-year-old child diagnosed with the help of Fine Needle Aspiration Cytology. The swelling resolved over a period of 18 months without any recurrence in 2-year follow-up period. This case report highlights the role of Fine Needle Aspiration Cytology in the diagnosis of Rosai-Dorfman disease and the importance of regular follow ups using a careful wait and watch approach in its management. The report also briefly discusses the various dilemmas associated with its diagnosis and treatment. PMID:25088489

  18. Massive Binaries in the Galactic Center

    NASA Astrophysics Data System (ADS)

    Figer, D. F.; Kim, S. S.

    We review the status of massive-star interaction research in the Galactic center (GC). Given the short lifetimes of massive stars, massive binaries will necessarily be located near their formation sites in starburst clusters. The GC contains three recently formed clusters having a very high stellar density, as high as 106 stars pc-3. We discuss these extreme environments, and possible massive binaries therein. In addition, we argue that they may host the products of massive stellar mergers and collisions. In particular, we predict that at least one massive star in the Arches cluster has already experienced stellar merger events in its short lifetime. Further, the Pistol Star, in the nearby Quintuplet cluster, might owe its apparent relative youth to a rejuvinating stellar merger. Finally, the apparently young stars in the central arcsecond could be products of either collisions, inducing atmospheric stripping, or mergers.

  19. Massive gravity with N=1 local supersymmetry

    NASA Astrophysics Data System (ADS)

    Malaeb, O.

    2013-09-01

    A consistent theory of massive gravity, where the graviton acquires mass by spontaneously breaking diffeomorphism invariance, is now well established. We supersymmetrize this construction using N=1 fields. Coupling to N=1 supergravity is done by applying the rules of tensor calculus to construct an action invariant under local N=1 supersymmetry. The supersymmetric action is shown, at the quadratic level, to be free of ghosts and have as its spectrum a massive graviton, two gravitinos (with different masses) and a massive vector.

  20. On "new massive" 4D gravity

    NASA Astrophysics Data System (ADS)

    Bergshoeff, Eric A.; Fernández-Melgarejo, J. J.; Rosseel, Jan; Townsend, Paul K.

    2012-04-01

    We construct a four-dimensional (4D) gauge theory that propagates, unitarily, the five polarization modes of a massive spin-2 particle. These modes are described by a "dual" graviton gauge potential and the Lagrangian is 4th-order in derivatives. As the construction mimics that of 3D "new massive gravity", we call this 4D model (linearized) "new massive dual gravity". We analyse its massless limit, and discuss similarities to the Eddington-Schrödinger model.

  1. Eccentricity boost of stars around shrinking massive black hole binaries

    NASA Astrophysics Data System (ADS)

    Iwasa, Mao; Seto, Naoki

    2016-06-01

    Based on a simple geometrical approach, we analyze the evolution of the Kozai-Lidov mechanism for stars around shrinking massive black hole binaries on circular orbits. We find that, due to a peculiar bifurcation pattern induced by the Newtonian potential of stellar clusters, the orbit of stars could become highly eccentric. This transition occurs abruptly for stars with small initial eccentricities. The approach presented in this paper may be useful for studying the Kozai-Lidov mechanism in various astrophysical contexts.

  2. Massive Pulmonary Embolism at the Onset of Acute Promyelocytic Leukemia

    PubMed Central

    Sorà, Federica; Chiusolo, Patrizia; Laurenti, Luca; Autore, Francesco; Giammarco, Sabrina; Sica, Simona

    2016-01-01

    Life-threatening bleeding is a major and early complication of acute promyelocytic leukemia (APL), but in the last years there is a growing evidence of thromboses in APL. We report the first case of a young woman with dyspnea as the first symptom of APL due to massive pulmonary embolism (PE) successfully treated with thrombolysis for PE and heparin. APL has been processed with a combination of all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) obtaining complete remission. PMID:27413520

  3. Triggered star formation in the environment of young massive stars

    NASA Astrophysics Data System (ADS)

    Gritschneder, Matthias; Naab, T.; Heitsch, F.; Burkert, A.

    Recent observations with the Spitzer Space Telescope show clear evidence that star formation takes place in the surrounding of young massive O-type stars, which are shaping their environment due to their powerful radiation and stellar winds. In this work we investigate the effect of ionising radiation of massive stars on the ambient interstellar medium (ISM): In particular we want to examine whether the UV-radiation of O-type stars can lead to the observed pillar-like structures and can trigger star formation. We developed a new implementation, based on a parallel Smooth Particle Hydrodynamics code (VINE), that allows an efficient treatment of the effect of ionising radiation from massive stars on their turbulent gaseous environment. Here we present first results at very high resolution. We show that ionising radiation can trigger the collapse of an otherwise stable molecular cloud. The arising structures resemble observed structures (e.g. the pillars of creation in the Eagle Nebula (M16) or the Horsehead Nebula B33). Including the effect of gravitation we find small regions that can be identified as formation places of individual stars. We conclude that ionising radiation from massive stars alone can trigger substantial star formation in molecular clouds.

  4. Massively parallel quantum computer simulator

    NASA Astrophysics Data System (ADS)

    De Raedt, K.; Michielsen, K.; De Raedt, H.; Trieu, B.; Arnold, G.; Richter, M.; Lippert, Th.; Watanabe, H.; Ito, N.

    2007-01-01

    We describe portable software to simulate universal quantum computers on massive parallel computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray X1E, a SGI Altix 3700 and clusters of PCs running Windows XP. We study the performance of the software by simulating quantum computers containing up to 36 qubits, using up to 4096 processors and up to 1 TB of memory. Our results demonstrate that the simulator exhibits nearly ideal scaling as a function of the number of processors and suggest that the simulation software described in this paper may also serve as benchmark for testing high-end parallel computers.

  5. Stable massive particles at colliders

    SciTech Connect

    Fairbairn, M.; Kraan, A.C.; Milstead, D.A.; Sjostrand, T.; Skands, P.; Sloan, T.; /Lancaster U.

    2006-11-01

    We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamental forces. This review describes the techniques used in SMP-searches at collider experiments and the limits so far obtained on the production of SMPs which possess various colour, electric and magnetic charge quantum numbers. We also describe theoretical scenarios which predict SMPs, the phenomenology needed to model their production at colliders and interactions with matter. In addition, the interplay between collider searches and open questions in cosmology such as dark matter composition are addressed.

  6. Massive supersymmetric quantum gauge theory

    NASA Astrophysics Data System (ADS)

    Grigore, D. R.; Gut, M.; Scharf, G.

    2005-08-01

    We continue the study of the supersymmetric vector multiplet in a purely quantum framework. We obtain some new results which make the connection with the standard literature. First we construct the one-particle physical Hilbert space taking into account the (quantum) gauge structure of the model. Then we impose the condition of positivity for the scalar product only on the physical Hilbert space. Finally we obtain a full supersymmetric coupling which is gauge invariant in the supersymmetric sense in the first order of perturbation theory. By integrating out the Grassmann variables we get an interacting Lagrangian for a massive Yang-Mills theory related to ordinary gauge theory; however the number of ghost fields is doubled so we do not obtain the same ghost couplings as in the standard model Lagrangian.

  7. Merlin - Massively parallel heterogeneous computing

    NASA Technical Reports Server (NTRS)

    Wittie, Larry; Maples, Creve

    1989-01-01

    Hardware and software for Merlin, a new kind of massively parallel computing system, are described. Eight computers are linked as a 300-MIPS prototype to develop system software for a larger Merlin network with 16 to 64 nodes, totaling 600 to 3000 MIPS. These working prototypes help refine a mapped reflective memory technique that offers a new, very general way of linking many types of computer to form supercomputers. Processors share data selectively and rapidly on a word-by-word basis. Fast firmware virtual circuits are reconfigured to match topological needs of individual application programs. Merlin's low-latency memory-sharing interfaces solve many problems in the design of high-performance computing systems. The Merlin prototypes are intended to run parallel programs for scientific applications and to determine hardware and software needs for a future Teraflops Merlin network.

  8. PRISM Polarimetry of Massive Stars

    NASA Astrophysics Data System (ADS)

    Kerkstra, Brennan; Lomax, Jamie R.; Bjorkman, Karen S.; Bjorkman, Jon Eric; Skiff, Brian; Covey, Kevin R.; Wisniewski, John P.

    2016-01-01

    We present the early results from our long-term, multi-epoch filter polarization survey of massive stars in and around young Galactic clusters. These BVRI polarization data were obtained using the PRISM instrument mounted on the 1.8m Perkins Telescope at Lowell Observatory. We first detail the creation of our new semi-automated polarization data reduction pipeline that we developed to process these data. Next, we present our analysis of the instrumental polarization properties of the PRISM instrument, via observations of polarized and unpolarized standard stars. Finally, we present early results on the total and intrinsic polarization behavior of several isolated, previously suggested classical Be stars, and discuss these results in the context of the larger project.BK acknowledges support from a NSF/REU at the University of Oklahoma. This program was also supported by NSF-AST 11411563, 1412110, and 1412135.

  9. Derivative couplings in massive bigravity

    NASA Astrophysics Data System (ADS)

    Gao, Xian; Heisenberg, Lavinia

    2016-03-01

    In this work we study the cosmological perturbations in massive bigravity in the presence of non-minimal derivative couplings. For this purpose we consider a specific subclass of Horndeski scalar-tensor interactions that live on the unique composite effective metric. For the viability of the model both metrics have to be dynamical. Nevertheless, the number of allowed kinetic terms is crucial. We adapt to the restriction of having one single kinetic term. After deriving the full set of equations of motion for flat Friedmann-Lemaitre-Robertson-Walker background, we study linear perturbations on top of it. We show explicitly that only four tensor, two vector and two scalar degrees of freedom propagate, one of which being the Horndeski scalar, while the Boulware-Deser ghost can be integrated out.

  10. Massively parallel MRI detector arrays

    NASA Astrophysics Data System (ADS)

    Keil, Boris; Wald, Lawrence L.

    2013-04-01

    Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas via reception, the term parallel imaging now includes the use of array coils to perform image encoding. This methodology has impacted clinical imaging to the point where many examinations are performed with an array comprising multiple smaller surface coil elements as the detector of the MR signal. This article reviews the theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called “ultimate” SNR and g-factor. We also review the methods for optimally combining array data and changes in RF methodology needed to construct massively parallel MRI detector arrays and show some examples of state-of-the-art for highly accelerated imaging with the resulting highly parallel arrays.

  11. Massively Parallel MRI Detector Arrays

    PubMed Central

    Keil, Boris; Wald, Lawrence L

    2013-01-01

    Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas, the term parallel imaging now includes the use of array coils to perform image encoding. This methodology has impacted clinical imaging to the point where many examinations are performed with an array comprising multiple smaller surface coil elements as the detector of the MR signal. This article reviews the theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called “ultimate” SNR and g-factor. We also review the methods for optimally combining array data and changes in RF methodology needed to construct massively parallel MRI detector arrays and show some examples of state-of-the-art for highly accelerated imaging with the resulting highly parallel arrays. PMID:23453758

  12. Massively parallel MRI detector arrays.

    PubMed

    Keil, Boris; Wald, Lawrence L

    2013-04-01

    Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas via reception, the term parallel imaging now includes the use of array coils to perform image encoding. This methodology has impacted clinical imaging to the point where many examinations are performed with an array comprising multiple smaller surface coil elements as the detector of the MR signal. This article reviews the theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called "ultimate" SNR and g-factor. We also review the methods for optimally combining array data and changes in RF methodology needed to construct massively parallel MRI detector arrays and show some examples of state-of-the-art for highly accelerated imaging with the resulting highly parallel arrays. PMID:23453758

  13. OT1_tgull_3: The Homunculus: Clues to Massive Ejection from the Most Massive Stars

    NASA Astrophysics Data System (ADS)

    Gull, T.

    2010-07-01

    Eta Carinae is a lynchpin between mass ejection by highly evolved massive stars and the enriched ISM. The Homunculus, a very dusty, neutral bipolar shell ejected in the 1840s, is known to contain at least 12 solar masses, based upon gas/dust=100. But this ejecta is very N-rich with C and O being 0.02 that of solar abundance. What dust formed and how much total mass was ejected? Our ultimate goal is to obtain the total ejected mass. We propose to obtain full spectral scans of the Homunculus with PACS and SPIRES and selected scans with HIFI. We will use these spectra to identify molecules and atomic species associated with this C- and O-depleted gas. While most of this depletion is due to CNO processing and conduction in stars > 60 solar masses, additional depletion is likely due to the first molecules and dust formed at high temperatures during the 1840s eruption. In line of sight we see overabundances of metals not ordinarily seen in the ISM: Sr, Sc, V. These metals have been trapped in atomic state due to limited O and C being available to form molecules. Yet dust has still formed. But what kind of dust? Through existing HST/STIS and VLT/UVES spectra combined with the proposed Herschel spectra and detailed modeling, we will gain much better insight on how molecules and dust can formed in depleted C,O conditions, and in turn provide an improved estimate of the total mass loss. Implications from this study apply to the first massive stars and the earliest dust in the Universe.

  14. Massive haemorrhage in liver transplantation: Consequences, prediction and management

    PubMed Central

    Cleland, Stuart; Corredor, Carlos; Ye, Jia Jia; Srinivas, Coimbatore; McCluskey, Stuart A

    2016-01-01

    From its inception the success of liver transplantation has been associated with massive blood loss. Massive transfusion is classically defined as > 10 units of red blood cells within 24 h, but describing transfusion rates over a shorter period of time may reduce the potential for survival bias. Both massive haemorrhage and transfusion are associated with increased risk of mortality and morbidity (need for dialysis/surgical site infection) following liver transplantation although causality is difficult to prove due to the observational design of most trials. The blood loss associated with liver transplantation is multifactorial. Portal hypertension secondary to cirrhosis results in extensive collateral circulation, which can bleed during hepatectomy particular if portal pressures are increased. Avoiding volume loading and maintenance of a low central venous pressure together with the use of vasopressors have been shown to reduce blood loss and transfusion during liver transplantation, but may increase the risk of renal impairment post-operatively. Coagulation defects may be present pre-transplant, but haemostasis is often re-balanced due to a deficit in both pro- and anti-coagulation factors. Further derangement of haemostasis may develop in the anhepatic and neohepatic phases due to absent hepatic metabolic function, hyperfibrinolysis and platelet sequestration in the donor liver. Point-of-care tests of coagulation such as the viscoelastic tests rotation thromboelastometry/thromboelastometry allow and more accurate and rapid assessment of these derangements in coagulation and guide the use of factor replacement and antifibrinolytics. Transfusion protocols guided by these tests have been shown to reduce transfusion rates compared with conventional coagulation tests, but have not shown improvements in mortality or morbidity. Pre-operative factors associated with massive transfusion include previous surgery, re-do transplantation, the aetiology and severity of liver

  15. Massive haemorrhage in liver transplantation: Consequences, prediction and management.

    PubMed

    Cleland, Stuart; Corredor, Carlos; Ye, Jia Jia; Srinivas, Coimbatore; McCluskey, Stuart A

    2016-06-24

    From its inception the success of liver transplantation has been associated with massive blood loss. Massive transfusion is classically defined as > 10 units of red blood cells within 24 h, but describing transfusion rates over a shorter period of time may reduce the potential for survival bias. Both massive haemorrhage and transfusion are associated with increased risk of mortality and morbidity (need for dialysis/surgical site infection) following liver transplantation although causality is difficult to prove due to the observational design of most trials. The blood loss associated with liver transplantation is multifactorial. Portal hypertension secondary to cirrhosis results in extensive collateral circulation, which can bleed during hepatectomy particular if portal pressures are increased. Avoiding volume loading and maintenance of a low central venous pressure together with the use of vasopressors have been shown to reduce blood loss and transfusion during liver transplantation, but may increase the risk of renal impairment post-operatively. Coagulation defects may be present pre-transplant, but haemostasis is often re-balanced due to a deficit in both pro- and anti-coagulation factors. Further derangement of haemostasis may develop in the anhepatic and neohepatic phases due to absent hepatic metabolic function, hyperfibrinolysis and platelet sequestration in the donor liver. Point-of-care tests of coagulation such as the viscoelastic tests rotation thromboelastometry/thromboelastometry allow and more accurate and rapid assessment of these derangements in coagulation and guide the use of factor replacement and antifibrinolytics. Transfusion protocols guided by these tests have been shown to reduce transfusion rates compared with conventional coagulation tests, but have not shown improvements in mortality or morbidity. Pre-operative factors associated with massive transfusion include previous surgery, re-do transplantation, the aetiology and severity of liver

  16. Massive Star Burps, Then Explodes

    NASA Astrophysics Data System (ADS)

    2007-04-01

    Berkeley -- In a galaxy far, far away, a massive star suffered a nasty double whammy. On Oct. 20, 2004, Japanese amateur astronomer Koichi Itagaki saw the star let loose an outburst so bright that it was initially mistaken for a supernova. The star survived, but for only two years. On Oct. 11, 2006, professional and amateur astronomers witnessed the star actually blowing itself to smithereens as Supernova 2006jc. Swift UVOT Image Swift UVOT Image (Credit: NASA / Swift / S.Immler) "We have never observed a stellar outburst and then later seen the star explode," says University of California, Berkeley, astronomer Ryan Foley. His group studied the event with ground-based telescopes, including the 10-meter (32.8-foot) W. M. Keck telescopes in Hawaii. Narrow helium spectral lines showed that the supernova's blast wave ran into a slow-moving shell of material, presumably the progenitor's outer layers ejected just two years earlier. If the spectral lines had been caused by the supernova's fast-moving blast wave, the lines would have been much broader. artistic rendering This artistic rendering depicts two years in the life of a massive blue supergiant star, which burped and spewed a shell of gas, then, two years later, exploded. When the supernova slammed into the shell of gas, X-rays were produced. (Credit: NASA/Sonoma State Univ./A.Simonnet) Another group, led by Stefan Immler of NASA's Goddard Space Flight Center, Greenbelt, Md., monitored SN 2006jc with NASA's Swift satellite and Chandra X-ray Observatory. By observing how the supernova brightened in X-rays, a result of the blast wave slamming into the outburst ejecta, they could measure the amount of gas blown off in the 2004 outburst: about 0.01 solar mass, the equivalent of about 10 Jupiters. "The beautiful aspect of our SN 2006jc observations is that although they were obtained in different parts of the electromagnetic spectrum, in the optical and in X-rays, they lead to the same conclusions," says Immler. "This

  17. Gravitational massive modes from extended gravity

    NASA Astrophysics Data System (ADS)

    Basini, Giuseppe; Capozziello, Salvatore; de Laurentis, Mariafelicia

    2016-02-01

    Further gravitational massive modes emerge by extending the geometrical sector of Hilbert-Einstein theory in the most general theory including curvature invariants. Besides massless spin-2, also spin-0 and spin-2 massive and ghost fields have to be considered. We investigate the possible detectability of such additional modes by the Large Hadron Collider and calculate the detectable energy density of the spectrum.

  18. Massive OB stars at varying Z

    NASA Astrophysics Data System (ADS)

    Herrero, A.; Garcia, M.; Simón-Díaz, S.; Camacho, I.; Sabín-Sanjulián, C.; Castro, N.

    2015-01-01

    Massive stars play a key role in environments with very different metallicities. To interpret the role of massive stars in these systems we have to know their properties at different metallicities. The Local Group offers an excellent laboratory to this aim.

  19. Stefan-Boltzmann Law for Massive Photons

    NASA Astrophysics Data System (ADS)

    Moreira, E. S.; Ribeiro, T. G.

    2016-04-01

    This paper generalizes the Stefan-Boltzmann law to include massive photons. A crucial ingredient to obtain the correct formula for the radiance is to realize that a massive photon does not travel at the speed of (massless) light. It follows that, contrary to what could be expected, the radiance is not proportional to the energy density times the speed of light.

  20. Stefan-Boltzmann Law for Massive Photons

    NASA Astrophysics Data System (ADS)

    Moreira, E. S.; Ribeiro, T. G.

    2016-08-01

    This paper generalizes the Stefan-Boltzmann law to include massive photons. A crucial ingredient to obtain the correct formula for the radiance is to realize that a massive photon does not travel at the speed of (massless) light. It follows that, contrary to what could be expected, the radiance is not proportional to the energy density times the speed of light.

  1. Influence of binary fraction on the fragmentation of young massive clusters—a Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanuka; Sinha, Abisa; Chattopadhyay, Asis Kumar

    2016-04-01

    A stochastic model has been developed to study the hierarchical fragmentation process of young massive clusters in external galaxies considering close binary components along with individual ones. Stellar masses for individual ones have been generated from truncated Pareto distribution and stellar masses for close binary components have been generated from a truncated Bi-variate Gumbel Exponential distribution. The above distribution is identified by fitting the observed bi-variate distribution of masses of eclipsing binary stars computed from the light curves catalogued in the package Binary Maker 3.0. The resulting mass spectra computed at different projected distances, show signature of mass segregation. Degree of mass segregation becomes reduced due to the inclusion of binary fraction. This might be due to the reduction of massive stars and inclusion of less massive stars rather than inclusion of single massive stars and the effect of line of sight length projected to an observer.

  2. Bending AdS waves with new massive gravity

    NASA Astrophysics Data System (ADS)

    Ayón-Beato, Eloy; Giribet, Gaston; Hassaïne, Mokhtar

    2009-05-01

    We study AdS-waves in the three-dimensional new theory of massive gravity recently proposed by Bergshoeff, Hohm, and Townsend. The general configuration of this type is derived and shown to exhibit different branches, with different asymptotic behaviors. In particular, for the special fine tuning m2 = ±1/(2l2), solutions with logarithmic fall-off arise, while in the range m2 > -1/(2l2), spacetimes with Schrödinger isometry group are admitted as solutions. Spacetimes that are asymptotically AdS3, both for the Brown-Henneaux and for the weakened boundary conditions, are also identified. The metric function that characterizes the profile of the AdS-wave behaves as a massive excitation on the spacetime, with an effective mass given by meff2 = m2-1/(2l2). For the critical value m2 = -1/(2l2), the value of the effective mass precisely saturates the Breitenlohner-Freedman bound for the AdS3 space where the wave is propagating on. The analogies with the AdS-wave solutions of topologically massive gravity are also discussed. Besides, we consider the coupling of both massive deformations to Einstein gravity and find the exact configurations for the complete theory, discussing all the different branches exhaustively. One of the effects of introducing the Chern-Simons gravitational term is that of breaking the degeneracy in the effective mass of the generic modes of pure New Massive Gravity, producing a fine structure due to parity violation. Another effect is that the zoo of exact logarithmic specimens becomes considerably enlarged.

  3. Remark on massive particle's de Sitter tunneling

    SciTech Connect

    Jiang, Qing-Quan; Chen, De-You; Wen, Dan E-mail: deyouchen@126.com

    2013-11-01

    In the work [J. Y. Zhang and Z. Zhao, Massive particles's black hole tunneling and de Sitter tunneling, Nucl. Phys. B 725 (2005) 173.], the Hawking radiation of the massive particle via tunneling from the de Sitter cosmological horizon has been first described in the tunneling framework. However, the geodesic equation of the massive particle was unnaturally and awkwardly defined there by investigating the relation between the group and phase velocity. In this paper, we start from the Lagrangian analysis on the action to naturally produce the geodesic equation of the tunneling massive particle. Then, based on the new definition for the geodesic equation, we revisit the Hawking radiation of the massive particle via tunneling from the de Sitter cosmological horizon. It is noteworthy that, the highlight of our work is a new and important development of the Parikh-Wilczek's tunneling method, which can make it more physical.

  4. Atypical: Analysis of a Massive Open Online Course (MOOC) with a Relatively High Rate of Program Completers

    ERIC Educational Resources Information Center

    Alemán de la Garza, Lorena Yadira; Sancho-Vinuesa, Teresa; Gómez Zermeño, Marcela Georgina

    2015-01-01

    Nowadays, Massive Open Online Courses (MOOCs) have raised great expectations due to their potential for changing the relationship between students and professors, academy and the general community. To conceptualize, the terms "course", "online", "massive" and "open" have been redefined and reinvented so many…

  5. Massively parallel femtosecond laser processing.

    PubMed

    Hasegawa, Satoshi; Ito, Haruyasu; Toyoda, Haruyoshi; Hayasaki, Yoshio

    2016-08-01

    Massively parallel femtosecond laser processing with more than 1000 beams was demonstrated. Parallel beams were generated by a computer-generated hologram (CGH) displayed on a spatial light modulator (SLM). The key to this technique is to optimize the CGH in the laser processing system using a scheme called in-system optimization. It was analytically demonstrated that the number of beams is determined by the horizontal number of pixels in the SLM NSLM that is imaged at the pupil plane of an objective lens and a distance parameter pd obtained by dividing the distance between adjacent beams by the diffraction-limited beam diameter. A performance limitation of parallel laser processing in our system was estimated at NSLM of 250 and pd of 7.0. Based on these parameters, the maximum number of beams in a hexagonal close-packed structure was calculated to be 1189 by using an analytical equation. PMID:27505815

  6. Linear growth of structure in massive bigravity

    SciTech Connect

    Solomon, Adam R.; Akrami, Yashar; Koivisto, Tomi S. E-mail: yashar.akrami@astro.uio.no

    2014-10-01

    The ghost-free theory of massive gravity with two dynamical metrics has been shown to produce viable cosmological expansion, where the late-time acceleration of the Universe is due to the finite range of the gravitational interaction rather than a nonzero cosmological constant. Here the cosmological perturbations are studied in this theory. The full perturbation equations are presented in a general gauge and analyzed, focusing on subhorizon scales in the quasistatic limit during the matter-dominated era. An evolution equation for the matter inhomogeneities and the parameters quantifying the deviations from general relativistic structure formation are expressed in terms of five functions whose forms are determined directly by the coupling parameters in the theory. The evolution equation has a similar structure to Horndeski-type scalar-tensor theories, exhibiting a modified growth rate and scale-dependence at intermediate wavenumbers. Predictions of the theory are confronted with observational data on both background expansion and large-scale structure, although care must be taken to ensure a model is stable. It is found that while the stable models fit the data well, they feature deviations from the standard cosmology that could be detected or ruled out by near-future experiments.

  7. Nonsurgical Treatment of a Massive Substance Loss

    PubMed Central

    Fino, Pasquale; Paolo, Fioramonti; Massera, Diego; Amorosi, Vittoria; Onesti, Maria Giuseppina

    2013-01-01

    Traumatic wounds are caused by severe trauma, resulting in lesions with extensive skin and subcutaneous tissue loss and damage to tissue viability. A “difficult wound” is a solution of continuity that does not heal spontaneously within three months. The factors that determine it may be as follows: a massive loss of substance, an infection, the presence of foreign bodies, or the clinical condition of the patient. We report a case of a 25-year-old man that presents a skin lesion on the anterior region of the left arm with extensive necrosis of skin and subcutaneous plants that involve the underlying muscle planes, caused by a trauma due to a car accident. In most of the lesions of such size and position, there is always a need for surgery. But in this case, considering the young age and the regenerative capacity of the patient, a quick and targeted antibiotic therapy was chosen, combined with debridement and worked with collagenase ointment. PMID:24073001

  8. Massive chondroma of pelvis - case report.

    PubMed

    Spindel, Jerzy; Stańkowski, Andrzej; Plaza, Jan; Chrobok, Adam; Wawrzynek, Wojciech; Tomasik, Patryk; Matysiakiewicz, Jacek

    2009-01-01

    The case of a massive pelvis chondroma in a 15-year-old male is described. The patient was previously treated operatively due to multiple chondro-osseous exostoses. An extensive chondrous tumour was detected in the patient's pelvis and abdomen during a follow-up visit. This was accompanied by symptoms of intestinal obstruction and impaired micturition. CT scans showed an extensive tumour filling the entire minor pelvic cavity and proximal femur with impression and infiltration of the femoral blood vessels, and displacement of both ureters, colon and urinary bladder causing urinary retention. The tumour caused severe disturbances of anatomical relations leading to dysfunction of the urinary and gastrointestinal systems. After appropriate preparation, the patient underwent surgery by a multidisciplinary team comprising an orthopaedic surgeon, a general surgeon and a urologist. After laparotomy and exposure of the retroperitoneal space, a giant (about 3.5 dm3) chondro-osseous tumour was resected. After 5 weeks another operation was made and another tumour, greater than an adult man's fist, was removed from the medial aspect of the right hip. The postoperative course was uncomplicated, the patient felt immediate relief as regards the urinary and gastrointestinal disturbances. His locomotion became noticeably better. A histological examination confirmed the preliminary diagnoses of a chondroma and a chondro-osseous lesion. Outpatient follow-up and additional work-up (ultrasound, CT) showed resolution of urine retention with an appropriate urinary bladder position and tumour-free minor pelvis cavity and proximal femur. PMID:19828919

  9. Radiative ablation of disks around massive stars

    NASA Astrophysics Data System (ADS)

    Kee, Nathaniel Dylan

    Hot, massive stars (spectral types O and B) have extreme luminosities (10. 4 -10. 6 L?) that drive strong stellar winds through UV line-scattering.Some massive stars also have disks, formed by either decretion from the star (as in the rapidly rotating "Classical Be stars"), or accretion during the star's formation. This dissertation examines the role of stellar radiation in driving (ablating) material away from these circumstellar disks. A key result is that the observed month to year decay of Classical Be disks can be explained by line-driven ablation without, as previously done, appealing to anomalously strong viscous diffusion. Moreover, the higher luminosity of O stars leads to ablation of optically thin disks on dynamical timescales of order a day, providing a natural explanation for the lack of observed Oe stars. In addition to the destruction of Be disks, this dissertation also introduces a model for their formation by coupling observationally inferred non-radial pulsation modes and rapid stellar rotation to launch material into orbiting Keplerian disks of Be-like densities. In contrast to such Be decretion disks, star-forming accretion disks are much denser and so are generally optically thick to continuum processes. To circumvent the computational challenges associated with radiation hydrodynamics through optically thick media, we develop an approximate method for treating continuum absorption in the limit of geometrically thin disks. The comparison of ablation with and without continuum absorption shows that accounting for disk optical thickness leads to less than a 50% reduction in ablation rate, implying that ablation rate depends mainly on stellar properties like luminosity. Finally, we discuss the role of "thin-shell mixing" in reducing X-rays from colliding wind binaries. Laminar, adiabatic shocks produce well understood X-ray emission, but the emission from radiatively cooled shocks is more complex due to thin-shell instabilities. The parameter

  10. Hemorrhagic pleural effusion due to pseudo-pancreatic cyst

    PubMed Central

    Sachdeva, Ruchi; Sachdeva, Sandeep

    2016-01-01

    Hemorrhagic pleural effusion is a common clinical entity still diagnosis is often missed. An unusual and often over-looked cause of pleural effusion is an intra-abdominal process including complication arising due to pancreatitis. We report a rare case of massive left sided hemorrhagic pleural effusion in a patient due to pancreatic pathology. PMID:27099855

  11. Evolved Massive Stars in the Local Group

    NASA Astrophysics Data System (ADS)

    Drout, M. R.; Massey, P.

    2015-05-01

    In this manuscript we describe a number of recent advances in the study of evolved massive stars in the Local Group, with an emphasis on how representative populations of these stars can be used to test models of massive star evolution. In honor of the 50th anniversary of the Cerro Tololo Inter-American Observatory (CTIO) we attempt to put these finding in some historical context by discussing how our understanding of the various stages in the lives of massive stars has evolved since Cerro Tololo was first selected as the site for the observatory which would become CTIO.

  12. Massive pulmonary embolism: the place for embolectomy

    PubMed Central

    Buckels, N J; Mulholland, C; Galvin, I; Gladstone, D; Cleland, J

    1988-01-01

    Untreated massive pulmonary embolism is associated with a high mortality. Pulmonary embolectomy has been largely superceded by thrombolytic therapy, but there are cases in which pulmonary embolectomy remains the treatment of choice. We present three case reports and discuss the merits of the various treatments available for massive pulmonary embolism. The primary treatment of massive pulmonary embolism should be thrombolytic therapy, but for patients who are at risk of haemorrhage following surgery, who are in cardiogenic shock despite medical treatment, or fail to improve following cardiac arrest, then pulmonary embolectomy remains the treatment of choice. ImagesFig 1Fig 2Fig 3 PMID:3232251

  13. Massive star archeology in globular clusters

    NASA Astrophysics Data System (ADS)

    Chantereau, W.; Charbonnel, C.; Meynet, G.

    2015-01-01

    Globular clusters are among the oldest structures in the Universe and they host today low-mass stars and no gas. However, there has been a time when they formed as gaseous objects hosting a large number of short-lived, massive stars. Many details on this early epoch have been depicted recently through unprecedented dissection of low-mass globular cluster stars via spectroscopy and photometry. In particular, multiple populations have been identified, which bear the nucleosynthetic fingerprints of the massive hot stars disappeared a long time ago. Here we discuss how massive star archeology can be done through the lense of these multiple populations.

  14. Venus - Volcano With Massive Landslides

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This Magellan full-resolution mosaic which covers an area 143 by 146 kilometers (89 by 91 miles) is centered at 55 degrees north latitude, 266 degrees east longitude. The bright feature, slightly south of center is interpreted to be a volcano, 15-20 kilometers (9.3 to 12.4 miles) in diameter with a large apron of blocky debris to its right and some smaller aprons to its left. A preferred explanation is that several massive catastrophic landslides dropped down steep slopes and were carried by their momentum out into the smooth, dark lava plains. At the base of the east-facing or largest scallop on the volcano is what appears to be a large block of coherent rock, 8 to 10 kilometers (5 to 6 miles) in length. The similar margin of both the scallop and block and the shape in general is typical of terrestrial slumped blocks (masses of rock which slide and rotate down a slope instead of breaking apart and tumbling). The bright lobe to the south of the volcano may either be a lava flow or finer debris from other landslides. This volcanic feature, characterized by its scalloped flanks is part of a class of volcanoes called scalloped or collapsed domes of which there are more than 80 on Venus. Based on the chute-like shapes of the scallops and the existence of a spectrum of intermediate to well defined examples, it is hypothesized that all of the scallops are remnants of landslides even though the landslide debris is often not visible. Possible explanations for the missing debris are that it may have been covered by lava flows, the debris may have weathered or that the radar may not be recognizing it because the individual blocks are too small

  15. Evolution of Massive Stars at Low Metallicity

    NASA Astrophysics Data System (ADS)

    Meynet, Georges; Walborn, Nolan R.; Hunter, Ian; Martayan, Christophe; van Marle, Allard Jan; Marchenko, Sergey; Vink, Jorick S.; Limongi, Marco; Levesque, Emily M.; Modjaz, Maryam

    2008-06-01

    This paper reports the contributions made on the occasion of the Special Session entitled “Evolution of Massive Stars at Low Metallicity” which was held on Sunday, December 9, 2007 in Kauai (USA).

  16. Recovering General Relativity from Massive Gravity

    SciTech Connect

    Babichev, E.; Deffayet, C.; Ziour, R.

    2009-11-13

    We obtain static, spherically symmetric, and asymptotically flat numerical solutions of massive gravity with a source. Those solutions show, for the first time explicitly, a recovery of the Schwarzschild solution of general relativity via the so-called Vainshtein mechanism.

  17. A cosmological study in massive gravity theory

    SciTech Connect

    Pan, Supriya Chakraborty, Subenoy

    2015-09-15

    A detailed study of the various cosmological aspects in massive gravity theory has been presented in the present work. For the homogeneous and isotropic FLRW model, the deceleration parameter has been evaluated, and, it has been examined whether there is any transition from deceleration to acceleration in recent past, or not. With the proper choice of the free parameters, it has been shown that the massive gravity theory is equivalent to Einstein gravity with a modified Newtonian gravitational constant together with a negative cosmological constant. Also, in this context, it has been examined whether the emergent scenario is possible, or not, in massive gravity theory. Finally, we have done a cosmographic analysis in massive gravity theory.

  18. Massive Stars: Input Physics and Stellar Models

    NASA Astrophysics Data System (ADS)

    El Eid, M. F.; The, L.-S.; Meyer, B. S.

    2009-10-01

    We present a general overview of the structure and evolution of massive stars of masses ≥12 M ⊙ during their pre-supernova stages. We think it is worth reviewing this topic owing to the crucial role of massive stars in astrophysics, especially in the evolution of galaxies and the universe. We have performed several test computations with the aim to analyze and discuss many physical uncertainties still encountered in massive-star evolution. In particular, we explore the effects of mass loss, convection, rotation, 12C( α, γ)16O reaction and initial metallicity. We also compare and analyze the similarities and differences among various works and ours. Finally, we present useful comments on the nucleosynthesis from massive stars concerning the s-process and the yields for 26Al and 60Fe.

  19. Management of massive and nonmassive pulmonary embolism

    PubMed Central

    Sekhri, Vishal; Mehta, Nimeshkumar; Rawat, Naveen; Lehrman, Stuart G.

    2012-01-01

    Massive pulmonary embolism (PE) is characterized by systemic hypotension (defined as a systolic arterial pressure < 90 mm Hg or a drop in systolic arterial pressure of at least 40 mm Hg for at least 15 min which is not caused by new onset arrhythmias) or shock (manifested by evidence of tissue hypoperfusion and hypoxia, including an altered level of consciousness, oliguria, or cool, clammy extremities). Massive pulmonary embolism has a high mortality rate despite advances in diagnosis and therapy. A subgroup of patients with nonmassive PE who are hemodynamically stable but with right ventricular (RV) dysfunction or hypokinesis confirmed by echocardiography is classified as submassive PE. Their prognosis is different from that of others with non-massive PE and normal RV function. This article attempts to review the evidence-based risk stratification, diagnosis, initial stabilization, and management of massive and nonmassive pulmonary embolism. PMID:23319967

  20. Dwarf Galaxies with Active Massive Black Holes

    NASA Astrophysics Data System (ADS)

    Reines, Amy E.; Greene, J. E.; Geha, M. C.

    2014-01-01

    Supermassive black holes (BHs) live at the heart of essentially all massive galaxies with bulges, power AGN, and are thought to be important agents in the evolution of their hosts. However, the birth and growth of the first supermassive BH "seeds" is far from understood. While direct observations of these distant BHs in the infant Universe are unobtainable with current capabilities, massive BHs in present-day dwarf galaxies can place valuable constraints on the masses, formation path, and hosts of supermassive BH seeds. Using optical spectroscopy from the SDSS, we have systematically assembled the largest sample of dwarf galaxies hosting active massive BHs to date. These dwarf galaxies have stellar masses comparable to the Magellanic Clouds and contain some of the least-massive supermassive BHs known.

  1. Self-protection of massive cosmological gravitons

    SciTech Connect

    Berkhahn, Felix; Dietrich, Dennis D.; Hofmann, Stefan E-mail: dietrich@cp3.sdu.dk

    2010-11-01

    Relevant deformations of gravity present an exciting window of opportunity to probe the rigidity of gravity on cosmological scales. For a single-graviton theory, the leading relevant deformation constitutes a graviton mass term. In this paper, we investigate the classical and quantum stability of massive cosmological gravitons on generic Friedman backgrounds. For a Universe expanding towards a de Sitter epoch, we find that massive cosmological gravitons are self-protected against unitarity violations by a strong coupling phenomenon.

  2. Primordial Li abundance and massive particles

    NASA Astrophysics Data System (ADS)

    ðapo, H.

    2012-10-01

    The problem of the observed lithium abundance coming from the Big Bang Nucleosynthesis is as of yet unsolved. One of the proposed solutions is including relic massive particles into the Big Bang Nucleosynthesis. We investigated the effects of such particles on 4HeX-+2H-->6Li+X-, where the X- is the negatively charged massive particle. We demonstrate the dominance of long-range part of the potential on the cross-section.

  3. Three-dimensional Casimir piston for massive scalar fields

    SciTech Connect

    Lim, S.C. Teo, L.P.

    2009-08-15

    We consider Casimir force acting on a three-dimensional rectangular piston due to a massive scalar field subject to periodic, Dirichlet and Neumann boundary conditions. Exponential cut-off method is used to derive the Casimir energy. It is shown that the divergent terms do not contribute to the Casimir force acting on the piston, thus render a finite well-defined Casimir force acting on the piston. Explicit expressions for the total Casimir force acting on the piston is derived, which show that the Casimir force is always attractive for all the different boundary conditions considered. As a function of a - the distance from the piston to the opposite wall, it is found that the magnitude of the Casimir force behaves like 1/a{sup 4} when a{yields}0{sup +} and decays exponentially when a{yields}{infinity}. Moreover, the magnitude of the Casimir force is always a decreasing function of a. On the other hand, passing from massless to massive, we find that the effect of the mass is insignificant when a is small, but the magnitude of the force is decreased for large a in the massive case.

  4. Massive Star Formation: Characterising Infall and Outflow in dense cores.

    NASA Astrophysics Data System (ADS)

    Akhter, Shaila; Cunningham, Maria; Harvey-Smith, Lisa; Jones, Paul Andrew; Purcell, Cormac; Walsh, Andrew John

    2015-08-01

    Massive stars are some of the most important objects in the Universe, shaping the evolution of galaxies, creating chemical elements, and hence shaping the evolution of the Universe. However, the processes by which they form, and how they shape their environment during their birth processes, are not well understood. We are using NH3 data from the "The H2O Southern Galactic Plane Survey" (HOPS) to define the positions of dense cores/clumps of gas in the southern Galactic plane that are likely to form stars. Due to its effective critical density, NH3 can detect massive star forming regions effectively compared to other tracers. We did a comparative study with different methods for finding clumps and found Fellwalker as the best. We found ~ 10% of the star forming clumps with multiple components and ~ 90% clumps with single component along the line of sight. Then, using data from the "The Millimetre Astronomy Legacy Team 90 GHz" (MALT90) survey, we search for the presence of infall and outflow associated with these cores. We will subsequently use the "3D Molecular Line Radiative Transfer Code" (MOLLIE) to constrain properties of the infall and outflow, such as velocity and mass flow. The aim of the project is to determine how common infall and outflow are in star forming cores, hence providing valuable constraints on the timescales and physical process involved in massive star formation.

  5. Massive scalar Casimir interaction beyond proximity force approximation

    NASA Astrophysics Data System (ADS)

    Teo, L. P.

    2015-09-01

    Since massive scalar field plays an important role in theoretical physics, we consider the interaction between a sphere and a plate due to the vacuum fluctuation of a massive scalar field. We consider combinations of Dirichlet and Neumann boundary conditions. There is a simple prescription to obtain the functional formulas for the Casimir interaction energies, known as TGTG formula, for the massive interactions from the massless interactions. From the TGTG formulas, we discuss how to compute the small separation asymptotic expansions of the Casimir interaction energies up to the next-to-leading order terms. Unlike the massless case, the results could not be expressed as simple algebraic expressions, but instead could only be expressed as infinite sums over some integrals. Nonetheless, it is easy to show that one can obtain the massless limits which agree with previously established results. We also show that the leading terms agree with that derive using proximity force approximation. The dependence of the leading order terms and the next-to-leading order terms on the mass of the scalar field is studied both numerically and analytically. In particular, we derive the small mass asymptotic expansions of these terms. Surprisingly, the small mass asymptotic expansions are quite complicated as they contain terms that are of odd powers in mass as well as logarithms of mass terms.

  6. A survey of extended H2 emission from massive YSOs

    NASA Astrophysics Data System (ADS)

    Navarete, F.; Damineli, A.; Barbosa, C. L.; Blum, R. D.

    2015-07-01

    We present the results from a survey, designed to investigate the accretion process of massive young stellar objects (MYSOs) through near-infrared narrow-band imaging using the H2 ν=1-0 S(1) transition filter. A sample of 353 MYSO candidates was selected from the Red MSX Source survey using photometric criteria at longer wavelengths (infrared and submillimetre) and chosen with positions throughout the Galactic plane. Our survey was carried out at the Southern Astrophysical Research Telescope Telescope in Chile and Canada-France-Hawaii Telescope in Hawaii covering both hemispheres. The data reveal that extended H2 emission is a good tracer of outflow activity, which is a signpost of accretion process on young massive stars. Almost half of the sample exhibit extended H2 emission and 74 sources (21 per cent) have polar morphology, suggesting collimated outflows. The polar-like structures are more likely to appear on radio-quiet sources, indicating these structures occur during the pre-UCH II phase. We also found an important fraction of sources associated with fluorescent H2 diffuse emission that could be due to a more evolved phase. The images also indicate only ˜23 per cent (80) of the sample is associated with extant (young) stellar clusters. These results support the scenario in which massive stars are formed by accretion discs, since the merging of low-mass stars would not produce outflow structures.

  7. Shifting from Stewardship to Analytics of Massive Science Data

    NASA Astrophysics Data System (ADS)

    Crichton, D. J.; Doyle, R.; Law, E.; Hughes, S.; Huang, T.; Mahabal, A.

    2015-12-01

    Currently, the analysis of large data collections is executed through traditional computational and data analysis approaches, which require users to bring data to their desktops and perform local data analysis. Data collection, archiving and analysis from future remote sensing missions, be it from earth science satellites, planetary robotic missions, or massive radio observatories may not scale as more capable instruments stress existing architectural approaches and systems due to more continuous data streams, data from multiple observational platforms, and measurements and models from different agencies. A new paradigm is needed in order to increase the productivity and effectiveness of scientific data analysis. This paradigm must recognize that architectural choices, data processing, management, analysis, etc are interrelated, and must be carefully coordinated in any system that aims to allow efficient, interactive scientific exploration and discovery to exploit massive data collections. Future observational systems, including satellite and airborne experiments, and research in climate modeling will significantly increase the size of the data requiring new methodological approaches towards data analytics where users can more effectively interact with the data and apply automated mechanisms for data reduction, reduction and fusion across these massive data repositories. This presentation will discuss architecture, use cases, and approaches for developing a big data analytics strategy across multiple science disciplines.

  8. Compound nucleus formation in reactions between massive nuclei: Fusion barrier

    SciTech Connect

    Antonenko, N.V.; Cherepanov, E.A.; Nasirov, A.K.; Permjakov, V.P.; Volkov, V.V.

    1995-05-01

    The evaporation residue cross sections {sigma}{sub ER} in reactions between massive nuclei have been analyzed within different models of complete fusion. The calculations in the framework of the optical model, the surface friction model, and the macroscopic dynamic model can give the results which are by few orders of magnitude different from experimental data. This takes place due to neglect of the competition between complete fusion and quasifission. A possible mechanism of compound nucleus formation in heavy-ion-induced reactions has been suggested. The analysis of the complete fusion of nuclei on the basis of dinuclear system approach has allowed one to reveal an important feature of the fusion process of massive nuclei, that is, the appearance of the fusion barrier during dinuclear system evolution to a compound nucleus. As a result, the competition between complete fusion and quasifission arises and strongly reduces the cross section of the compound nucleus formation. A model is proposed for calculation of this competition in a massive symmetric dinuclear system. This model is applied for collision energies above the Coulomb barrier. The {sigma}{sub ER} values calculated in the framework of dinuclear system approach seem to be close to the experimental data. For illustration the reactions {sup 100}Mo+{sup 100}Mo, {sup 110}Pd+{sup 110}Pd, and {sup 124}Sn+{sup 96}Zr have been considered.

  9. Tracing the Formation and Evolution of Massive Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Davari, Roozbeh

    Massive galaxies at higher redshift, z > 2, show different characteristics than their local counterparts. They are compact and most likely have a disk. Understanding the evolutionary path of these massive galaxies can give us some clues on how the universe has been behaving in the last 10 billion years. How well can we measure the bulge and disk properties of these systems? We perform two sets of comprehensive simulations in order to systematically quantify the effects of non-homology in structures and the methods employed. For the first set of simulations, by accurately capturing the detailed substructures of nearby elliptical galaxies and then rescaling their sizes and signal-to-noise to mimic galaxies at different redshifts, we confirm that the massive quiescent galaxies at z ≈ 2 are significantly more compact intrinsically than their local counterparts. Their observed compactness is not a result of missing faint outer light due to systematic errors in modeling. For the second set of simulations, we employ empirical scaling relations to produce realistic-looking two-component local galaxies with a uniform and wide range of bulge-to-total ratios (B/T), and then rescale them to mimic the signal-to-noise ratios and sizes of observed galaxies at z ≈ 2. This provides the first set of simulations for which we can examine the robustness of two-component decomposition of compact disk galaxies at different B/T . We can measure B/T accurately without imposing any constraints on the light profile shape of the bulge, but, due to the small angular sizes of bulges at high redshift, their detailed properties can only be recovered for galaxies with B/T ≥ 0.2. The disk component, by contrast, can be measured with little difficulty. Next, we trace back the evolution of local massive galaxies but performing detailed morphological analysis: namely, single Swrsic fitting and bulge+disk decomposition. CANDELS images and catalogues offer an ideal dataset for this study. We

  10. THE ROLE OF THE MAGNETOROTATIONAL INSTABILITY IN MASSIVE STARS

    SciTech Connect

    Wheeler, J. Craig; Kagan, Daniel; Chatzopoulos, Emmanouil

    2015-01-20

    The magnetorotational instability (MRI) is key to physics in accretion disks and is widely considered to play some role in massive star core collapse. Models of rotating massive stars naturally develop very strong shear at composition boundaries, a necessary condition for MRI instability, and the MRI is subject to triply diffusive destabilizing effects in radiative regions. We have used the MESA stellar evolution code to compute magnetic effects due to the Spruit-Tayler (ST) mechanism and the MRI, separately and together, in a sample of massive star models. We find that the MRI can be active in the later stages of massive star evolution, leading to mixing effects that are not captured in models that neglect the MRI. The MRI and related magnetorotational effects can move models of given zero-age main sequence mass across ''boundaries'' from degenerate CO cores to degenerate O/Ne/Mg cores and from degenerate O/Ne/Mg cores to iron cores, thus affecting the final evolution and the physics of core collapse. The MRI acting alone can slow the rotation of the inner core in general agreement with the observed ''initial'' rotation rates of pulsars. The MRI analysis suggests that localized fields ∼10{sup 12} G may exist at the boundary of the iron core. With both the ST and MRI mechanisms active in the 20 M {sub ☉} model, we find that the helium shell mixes entirely out into the envelope. Enhanced mixing could yield a population of yellow or even blue supergiant supernova progenitors that would not be standard SN IIP.

  11. The Role of the Magnetorotational Instability in Massive Stars

    NASA Astrophysics Data System (ADS)

    Wheeler, J. Craig; Kagan, Daniel; Chatzopoulos, Emmanouil

    2015-01-01

    The magnetorotational instability (MRI) is key to physics in accretion disks and is widely considered to play some role in massive star core collapse. Models of rotating massive stars naturally develop very strong shear at composition boundaries, a necessary condition for MRI instability, and the MRI is subject to triply diffusive destabilizing effects in radiative regions. We have used the MESA stellar evolution code to compute magnetic effects due to the Spruit-Tayler (ST) mechanism and the MRI, separately and together, in a sample of massive star models. We find that the MRI can be active in the later stages of massive star evolution, leading to mixing effects that are not captured in models that neglect the MRI. The MRI and related magnetorotational effects can move models of given zero-age main sequence mass across "boundaries" from degenerate CO cores to degenerate O/Ne/Mg cores and from degenerate O/Ne/Mg cores to iron cores, thus affecting the final evolution and the physics of core collapse. The MRI acting alone can slow the rotation of the inner core in general agreement with the observed "initial" rotation rates of pulsars. The MRI analysis suggests that localized fields ~1012 G may exist at the boundary of the iron core. With both the ST and MRI mechanisms active in the 20 M ⊙ model, we find that the helium shell mixes entirely out into the envelope. Enhanced mixing could yield a population of yellow or even blue supergiant supernova progenitors that would not be standard SN IIP.

  12. Scalable Machine Learning for Massive Astronomical Datasets

    NASA Astrophysics Data System (ADS)

    Ball, Nicholas M.; Astronomy Data Centre, Canadian

    2014-01-01

    We present the ability to perform data mining and machine learning operations on a catalog of half a billion astronomical objects. This is the result of the combination of robust, highly accurate machine learning algorithms with linear scalability that renders the applications of these algorithms to massive astronomical data tractable. We demonstrate the core algorithms kernel density estimation, K-means clustering, linear regression, nearest neighbors, random forest and gradient-boosted decision tree, singular value decomposition, support vector machine, and two-point correlation function. Each of these is relevant for astronomical applications such as finding novel astrophysical objects, characterizing artifacts in data, object classification (including for rare objects), object distances, finding the important features describing objects, density estimation of distributions, probabilistic quantities, and exploring the unknown structure of new data. The software, Skytree Server, runs on any UNIX-based machine, a virtual machine, or cloud-based and distributed systems including Hadoop. We have integrated it on the cloud computing system of the Canadian Astronomical Data Centre, the Canadian Advanced Network for Astronomical Research (CANFAR), creating the world's first cloud computing data mining system for astronomy. We demonstrate results showing the scaling of each of our major algorithms on large astronomical datasets, including the full 470,992,970 objects of the 2 Micron All-Sky Survey (2MASS) Point Source Catalog. We demonstrate the ability to find outliers in the full 2MASS dataset utilizing multiple methods, e.g., nearest neighbors, and the local outlier factor. 2MASS is used as a proof-of-concept dataset due to its convenience and availability. These results are of interest to any astronomical project with large and/or complex datasets that wishes to extract the full scientific value from its data.

  13. Scalable Machine Learning for Massive Astronomical Datasets

    NASA Astrophysics Data System (ADS)

    Ball, Nicholas M.; Gray, A.

    2014-04-01

    We present the ability to perform data mining and machine learning operations on a catalog of half a billion astronomical objects. This is the result of the combination of robust, highly accurate machine learning algorithms with linear scalability that renders the applications of these algorithms to massive astronomical data tractable. We demonstrate the core algorithms kernel density estimation, K-means clustering, linear regression, nearest neighbors, random forest and gradient-boosted decision tree, singular value decomposition, support vector machine, and two-point correlation function. Each of these is relevant for astronomical applications such as finding novel astrophysical objects, characterizing artifacts in data, object classification (including for rare objects), object distances, finding the important features describing objects, density estimation of distributions, probabilistic quantities, and exploring the unknown structure of new data. The software, Skytree Server, runs on any UNIX-based machine, a virtual machine, or cloud-based and distributed systems including Hadoop. We have integrated it on the cloud computing system of the Canadian Astronomical Data Centre, the Canadian Advanced Network for Astronomical Research (CANFAR), creating the world's first cloud computing data mining system for astronomy. We demonstrate results showing the scaling of each of our major algorithms on large astronomical datasets, including the full 470,992,970 objects of the 2 Micron All-Sky Survey (2MASS) Point Source Catalog. We demonstrate the ability to find outliers in the full 2MASS dataset utilizing multiple methods, e.g., nearest neighbors. This is likely of particular interest to the radio astronomy community given, for example, that survey projects contain groups dedicated to this topic. 2MASS is used as a proof-of-concept dataset due to its convenience and availability. These results are of interest to any astronomical project with large and/or complex

  14. Casimir effect of massive vector fields

    SciTech Connect

    Teo, L. P.

    2010-11-15

    We study the Casimir effect due to a massive vector field in a system of two parallel plates made of real materials, in an arbitrary magnetodielectric background. The plane waves satisfying the Proca equations are classified into transverse modes and longitudinal modes which have different dispersion relations. Transverse modes are further divided into type I and type II corresponding to TE and TM modes in the massless case. For general magnetodielectric media, we argue that the correct boundary conditions are the continuities of H{sub ||}, {phi}, A, and {partial_derivative}{sub x}A{sub x}, where x is the direction normal to the plates. Although there are type I transverse modes that satisfy all the boundary conditions, it is impossible to find type II transverse modes or longitudinal modes that satisfy all the boundary conditions. To circumvent this problem, type II transverse modes and longitudinal modes have to be considered together. We call the contribution to the Casimir energy from type I transverse modes TE contribution, and the contribution from the superposition of type II transverse modes and longitudinal modes TM contribution. Their massless limits give, respectively, the TE and TM contributions to the Casimir energy of a massless vector field. The limit where the plates become perfectly conducting is discussed in detail. For the special case where the background has a unity refractive index, it is shown that the TM contribution to the Casimir energy can be written as a sum of contributions from two different types of modes, corresponding to type II discrete modes and type III continuum modes discussed by Barton and Dombey [G. Barton and N. Dombey, Ann. Phys. (N.Y.) 162, 231 (1985).]. For general background, this splitting does not work. The limit where both plates become infinitely permeable and the limit where one plate becomes perfectly conducting and one plate becomes infinitely permeable are also investigated.

  15. Strongyloidiasis in immunosuppressed hosts. Presentation as massive lower gastrointestinal bleeding.

    PubMed

    Powell, R W; Moss, J P; Nagar, D; Melo, J C; Boram, L H; Anderson, W H; Cheng, S H

    1980-08-01

    Two cases of massive lower gastrointestinal hemorrhage in immunosuppressed patients were due to complicated infestation with Strongyloides stercoralis. The very high mortality of disseminated strongyloidiasis may in part be attributed to delays in diagnosis and treatment resulting from the complex life cycle of this nematode. Successful therapy in the cases presented consisted of reduction of corticosteroid dosage, use of thiabendazole in excess of that recommended for uncomplicated infestation, parenterally administered nutrition, multiple transfusion of blood products, and vigorous supportive management. Emphasis is given to proper categorization of patients and measures designed to prevent, detect, and treat hyperinfection in patients in whom immunosuppression is anticipated. PMID:6967302

  16. Massive relic galaxies prefer dense environments

    NASA Astrophysics Data System (ADS)

    Peralta de Arriba, Luis; Quilis, Vicent; Trujillo, Ignacio; Cebrián, María; Balcells, Marc

    2016-09-01

    We study the preferred environments of z ˜ 0 massive relic galaxies (M⋆ ≳ 1010 M⊙ galaxies with little or no growth from star formation or mergers since z ˜ 2). Significantly, we carry out our analysis on both a large cosmological simulation and an observed galaxy catalogue. Working on the Millennium I-WMAP7 simulation we show that the fraction of today massive objects which have grown less than 10 per cent in mass since z ˜ 2 is ˜0.04 per cent for the whole massive galaxy population with M⋆ > 1010 M⊙. This fraction rises to ˜0.18 per cent in galaxy clusters, confirming that clusters help massive galaxies remain unaltered. Simulations also show that massive relic galaxies tend to be closer to cluster centres than other massive galaxies. Using the New York University Value-Added Galaxy Catalogue, and defining relics as M⋆ ≳ 1010 M⊙ early-type galaxies with colours compatible with single-stellar population ages older than 10 Gyr, and which occupy the bottom 5-percentile in the stellar mass-size distribution, we find 1.11 ± 0.05 per cent of relics among massive galaxies. This fraction rises to 2.4 ± 0.4 per cent in high-density environments. Our findings point in the same direction as the works by Poggianti et al. and Stringer et al. Our results may reflect the fact that the cores of the clusters are created very early on, hence the centres host the first cluster members. Near the centres, high-velocity dispersions and harassment help cluster core members avoid the growth of an accreted stellar envelope via mergers, while a hot intracluster medium prevents cold gas from reaching the galaxies, inhibiting star formation.

  17. Quantized massive collective modes and massive spin fluctuations in high-Tc cuprates

    NASA Astrophysics Data System (ADS)

    Kanazawa, I.; Sasaki, T.

    2015-10-01

    We have analyzed angle-resolved photoemission spectra of the single- and double-layered Bi-family high-Tc superconductors by using quantized massive gauge fields, which might contain effects of spin fluctuations, charge fluctuations, and phonons. It is suggested strongly that the quantized massive gauge fields might be mediating Cooper pairing in high-Tc cuprates.

  18. Clarifying Massive Protostellar Evolution and Circumstellar Processing

    NASA Astrophysics Data System (ADS)

    Indebetouw, Remy; Brogan, Crystal; Hoare, Melvin; Lumsden, Stuart; Robitaille, Thomas; Sewilo, Marta; Urquhart, James; Viti, Serena; Whitney, Barbara

    2008-03-01

    Massive stars dominate the evolution of galaxies and even as protostars, their feedback can affect their own formation and that of their host clusters. We propose a systematic study of massive protostars through the stages of their early evolution, to derive a clearer evolutionary sequence and a better link between the state of the central source and physical conditions in circumstellar material. This experiment will improve over existing work by careful source selection to systematically span evolutionary parameter space, resulting in a more uniform and comprehensive sample. Sophisticated radiative transfer, ionization, and chemical modeling will be used to extract the full riches of each IRS spectrum and find trends in how massive stars form and process their natal material: We will be able to determine the temperature, density, and chemical state (heating history) of circumstellar dust and ice in the accretion disk and envelope, and at later evolutionary stages the ionizing and soft (PAH-exciting) ultraviolet radiation emitted by the protostars and how that radiation is quenched and shadowed by circumstellar material. This investigation is the key to realizing the full potential of previous infrared imaging surveys like MSX and Spitzer's GLIMPSE and MIPSGAL to study massive star formation. These surveys have provided a basis for us to select a large relatively unbiased sample spanning evolutionary state. In return, revealing the spectroscopic signature of massive YSOs will greatly clarify the modeling and interpretation of the thousands of other protostars in these imaging survey data.

  19. Hot Massive Stars: The Impact of HST

    NASA Astrophysics Data System (ADS)

    Crowther, Paul A.

    We review the contribution of Hubble Space Telescope to the study of hot, luminous stars. Optical and IR imaging have permitted spatially resolved observations of young, massive clusters within Local Group galaxies, such as R136, NGC 3603 and Arches, revealing unprecedented concentrations of very massive O stars. UV spectroscopy of field OB stars in the Magellanic Clouds have provided suitable templates for interpretation of metal-poor star-forming galaxies at high-redshift. Spectacular imaging provides the detailed structure of ejecta nebulae from individual stars, including the Homunculus associated with η Carinae and M1-67, associated with a Wolf-Rayet star. HST has permitted individual massive stars to be spatially resolved in giant HII regions located beyond the Local Group, such as NGC 604, plus individual clusters, dominated by the light of massive stars within starburst galaxies at larger distances, such as NGC 3125. UV spectroscopy of young, massive clusters in the extremely metal-poor HII galaxy I Zw 18 include signatures of large numbers of Wolf-Rayet stars.

  20. New VLA Observations of Massive Protostars: A Search for Jets

    NASA Astrophysics Data System (ADS)

    Rosero, Viviana; Hofner, Peter; Claussen, Mark

    2015-08-01

    Molecular outflows appear to be an ubiquitous phenomena among stars of all masses. However, to date only a handful of sources with disks and collimated jets have been detected in young massive objects (YMOs). It is not clear if the lack of detections are due to intrinsic properties of YMOs or due to observational disadvantages. We have performed a survey of ~60 YMOs with unprecedented sensitivity, using the Karl G. Jansky Very Large Array (VLA) to achieve ~3-10 microJy RMS in C and K-band images (about 10-100 times more sensitive than previous efforts). The sample is composed of the earliest stages of massive star formation: hot molecular cores and infrared dark cloud cores. Moreover, all the sources show signatures of massive star formation such as methanol and water masers and outflow phenomena. This study provides a sample of jet candidates which is a valuable basis for a follow up search for associated disks. In this contribution we present our observational results from the survey. We have a high detection rate of weak radio continuum emission from the YMOs in our sample, most of which were previously undetected. In addition to the jet scenario, we are analyzing which other processes could be producing the radio emission; some of the detections appear to be from non-thermal emission, and others could be associated with ultra-compact HII regions. Before the upgrade of the VLA, most of the HII regions detected were B0 type stars (or earlier). Hence, these highly sensitive sample of YSOs open a new door of results, from HII regions associated with late B-type stars to very weak, collimated ionized jets associated to very early YMOs.

  1. HOW TO FIND YOUNG MASSIVE CLUSTER PROGENITORS

    SciTech Connect

    Bressert, E.; Longmore, S.; Testi, L.; Ginsburg, A.; Bally, J.; Battersby, C.

    2012-10-20

    We propose that bound, young massive stellar clusters form from dense clouds that have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback in the form of gas ionization is bottled up, enabling star formation to proceed to sufficiently high efficiency so that the resulting star cluster remains bound even after gas removal. We estimate the observable properties of the massive proto-clusters (MPCs) for existing Galactic plane surveys and suggest how they may be sought in recent and upcoming extragalactic observations. These surveys will potentially provide a significant sample of MPC candidates that will allow us to better understand extreme star-formation and massive cluster formation in the Local Universe.

  2. How to Find Young Massive Cluster Progenitors

    NASA Astrophysics Data System (ADS)

    Bressert, E.; Ginsburg, A.; Bally, J.; Battersby, C.; Longmore, S.; Testi, L.

    2012-10-01

    We propose that bound, young massive stellar clusters form from dense clouds that have escape speeds greater than the sound speed in photo-ionized gas. In these clumps, radiative feedback in the form of gas ionization is bottled up, enabling star formation to proceed to sufficiently high efficiency so that the resulting star cluster remains bound even after gas removal. We estimate the observable properties of the massive proto-clusters (MPCs) for existing Galactic plane surveys and suggest how they may be sought in recent and upcoming extragalactic observations. These surveys will potentially provide a significant sample of MPC candidates that will allow us to better understand extreme star-formation and massive cluster formation in the Local Universe.

  3. Pseudoangiomatous stromal hyperplasia causing massive breast enlargement.

    PubMed

    Bourke, Anita Geraldine; Tiang, Stephen; Harvey, Nathan; McClure, Robert

    2015-01-01

    Pseudoangiomatous stromal hyperplasia (PASH) of the breast is a benign mesenchymal proliferative process, initially described by Vuitch et al. We report an unusual case of a 46-year-old woman who presented with a 6-week history of bilateral massive, asymmetrical, painful enlargement of her breasts, without a history of trauma. On clinical examination, both breasts were markedly enlarged and oedematous, but there were no discrete palpable masses. Preoperative image-guided core biopsies and surgery showed PASH. PASH is increasingly recognised as an incidental finding on image-guided core biopsy performed for screen detected lesions. There are a few reported cases of PASH presenting as rapid breast enlargement. In our case, the patient presented with painful, asymmetrical, massive breast enlargement. Awareness needs to be raised of this entity as a differential diagnosis in massive, painful breast enlargement. PMID:26475873

  4. Thermographic inspection of massive structures

    SciTech Connect

    Renshaw, Jeremy B.; Guimaraes, Maria; Scott, David B.

    2014-02-18

    Nondestructive Evaluation of concrete structures is a growing concern for the nuclear industry as well as for many other industries. As critical concrete components continue to age, the ability to assess the health and suitability for continued service has become a key consideration. In some cases, repair of these structures is difficult and expensive, while replacement is prohibitively expensive or, in some cases, not feasible. Therefore, the ability to inspect these key assets is a primary concern, especially in the nuclear industry. Due to the large size of containment buildings, cooling towers, and other large concrete assets, the ability to rapidly inspect for defects of concern is very desirable. Thermographic inspection appears to have the required ability to rapidly inspect large structures to ascertain the location and size of many of the defects of concern. This ability was demonstrated by performing a thermographic inspection of a large concrete dam in 2 days.

  5. Thermographic inspection of massive structures

    NASA Astrophysics Data System (ADS)

    Renshaw, Jeremy B.; Guimaraes, Maria; Scott, David B.

    2014-02-01

    Nondestructive Evaluation of concrete structures is a growing concern for the nuclear industry as well as for many other industries. As critical concrete components continue to age, the ability to assess the health and suitability for continued service has become a key consideration. In some cases, repair of these structures is difficult and expensive, while replacement is prohibitively expensive or, in some cases, not feasible. Therefore, the ability to inspect these key assets is a primary concern, especially in the nuclear industry. Due to the large size of containment buildings, cooling towers, and other large concrete assets, the ability to rapidly inspect for defects of concern is very desirable. Thermographic inspection appears to have the required ability to rapidly inspect large structures to ascertain the location and size of many of the defects of concern. This ability was demonstrated by performing a thermographic inspection of a large concrete dam in 2 days.

  6. Asphyxia by Drowning Induces Massive Bleeding Due To Hyperfibrinolytic Disseminated Intravascular Coagulation

    PubMed Central

    Schwameis, Michael; Schober, Andreas; Schörgenhofer, Christian; Sperr, Wolfgang Reinhard; Schöchl, Herbert; Janata-Schwatczek, Karin; Kürkciyan, Erol Istepan; Sterz, Fritz

    2015-01-01

    Objective: To date, no study has systematically investigated the impact of drowning-induced asphyxia on hemostasis. Our objective was to test the hypothesis that asphyxia induces bleeding by hyperfibrinolytic disseminated intravascular coagulation. Design: Observational study. Setting: A 2,100-bed tertiary care facility in Vienna, Austria, Europe. Patients: All cases of drowning-induced asphyxia (n = 49) were compared with other patients with cardiopulmonary resuscitation (n = 116) and to patients with acute promyelocytic leukemia (n = 83). Six drowning victims were investigated prospectively. To study the mechanism, a forearm-ischemia model was used in 20 volunteers to investigate whether hypoxia releases tissue plasminogen activator. Interventions: None. Measurements and Main Results: Eighty percent of patients with drowning-induced asphyxia developed overt disseminated intravascular coagulation within 24 hours. When compared with nondrowning cardiac arrest patients, drowning patients had a 13 times higher prevalence of overt disseminated intravascular coagulation at admission (55% vs 4%; p < 0.001). Despite comparable disseminated intravascular coagulation scores, acute promyelocytic leukemia patients had higher fibrinogen but lower d-dimer levels and platelet counts than drowning patients (p < 0.001). Drowning victims had a three-fold longer activated partial thromboplastin time (124 s; p < 0.001) than both nondrowning cardiac arrest and acute promyelocytic leukemia patients. Hyperfibrinolysis was reflected by up to 1,000-fold increased d-dimer levels, greater than 5-fold elevated plasmin antiplasmin levels, and a complete absence of thrombelastometric clotting patterns, which was reversed by antifibrinolytics and heparinase. Thirty minutes of forearm-ischemia increased tissue plasminogen activator 31-fold (p < 0.001). Conclusions: The vast majority of drowning patients develops overt hyperfibrinolytic disseminated intravascular coagulation, partly caused by hypoxia induced tissue plasminogen activator release. Antifibrinolytics and heparinase partially reverse the abnormal clotting patterns. Severe activated partial thromboplastin time prolongation may be a marker of combined hyperfibrinolytic afibrinogenemia and autoheparinization in drowning-related asphyxia. PMID:26327200

  7. Detection of enhancement in number densities of background galaxies due to magnification by massive galaxy clusters

    DOE PAGESBeta

    Chiu, I.; Dietrich, J. P.; Mohr, J.; Applegate, D. E.; Benson, B. A.; Bleem, L. E.; Bayliss, M. B.; Bocquet, S.; Carlstrom, J. E.; Capasso, R.; et al

    2016-02-18

    We present a detection of the enhancement in the number densities of background galaxies induced from lensing magnification and use it to test the Sunyaev-Zel'dovich effect (SZE) inferred masses in a sample of 19 galaxy clusters with median redshift z≃0.42 selected from the South Pole Telescope SPT-SZ survey. Two background galaxy populations are selected for this study through their photometric colours; they have median redshifts zmedian≃0.9 (low-z background) and zmedian≃1.8 (high-z background). Stacking these populations, we detect the magnification bias effect at 3.3σ and 1.3σ for the low- and high-z backgrounds, respectively. We fit NFW models simultaneously to all observedmore » magnification bias profiles to estimate the multiplicative factor η that describes the ratio of the weak lensing mass to the mass inferred from the SZE observable-mass relation. We further quantify systematic uncertainties in η resulting from the photometric noise and bias, the cluster galaxy contamination and the estimations of the background properties. The resulting η for the combined background populations with 1σ uncertainties is 0.83 ± 0.24(stat) ± 0.074(sys), indicating good consistency between the lensing and the SZE-inferred masses. We also use our best-fit η to predict the weak lensing shear profiles and compare these predictions with observations, showing agreement between the magnification and shear mass constraints. Our work demonstrates the promise of using the magnification as a complementary method to estimate cluster masses in large surveys.« less

  8. [Patient with massive hemothorax due to blunt trauma saved by transcatheter arterial embolization (TAE)].

    PubMed

    Ishida, Itaru; Oura, Hiroyuki; Kawakami, Toru; Shiga, Kojiro; Sakatsume, Ko; Sasaki, Yasuo; Sekizawa, Takuro; Handa, Masashi

    2013-06-01

    A 78-year-old man who fell from a step ladder was transported to our hospital by ambulance under the diagnosis of multiple rib fractures and right hemothorax. Since he was in shock on arrival, endotracheal intubation and tube thoracotomy were immediately performed. Though 2 liters of blood was evacuated, persistent hemorrhage was observed, requiring continuous rapid infusion and blood transfusion. Emergency thoracic arteriography revealed active bleeding from a branch of the right internal thoracic artery. Transcatheter arterial embolization (TAE) was performed using vascular embolization coils and porous gelatin particles. These procedures successfully controlled active hemorrhage from the chest. Intrathoracic hematoma was evacuated through the 2nd large chest tube. Chest tubes were removed on the 7th day. He was discharged on the 17th day without any complications. PMID:23917046

  9. Massive Bone Loss Due to Orchidectomy and Localized Disuse: Preventive Effects of a Biosphonsphonate

    NASA Astrophysics Data System (ADS)

    Libouban, H.; Moreau, M. F.; Chappard, D.

    2008-06-01

    Orchidectomy (ORX) and hindlimb paralysis induced by botulinum neurotoxin (BTX) were combined to see if their effects were cumulative and if bone loss could be prevented by an antiresorptive agent (risedronate) or testosterone. Four groups of mature rats were studied for 1 month: SHAM operated; ORX and right hindlimb immobilization (BTX); ORX+BTX+risedronate or testosterone. Bone loss and microarchitecture deterioration were maximized on the immobilized bone. Risedronate but not testosterone prevented trabecular bone loss but was less effective on cortical bone loss. ORX and BTX had additive effects on bone loss which can be prevented by risedronate but not testosterone.

  10. Detection of Enhancement in Number Densities of Background Galaxies due to Magnification by Massive Galaxy Clusters

    SciTech Connect

    Chiu, I.

    2015-10-06

    We present a detection of the enhancement in the number densities of background galaxies induced from lensing magnification and use it to test the Sunyaev-Zel'dovich effect (SZE) inferred masses in a sample of 19 galaxy clusters with median redshift z≃0.42 selected from the South Pole Telescope SPT-SZ survey. Two background galaxy populations are selected for this study through their photometric colours; they have median redshifts zmedian≃0.9 (low-z background) and zmedian≃1.8 (high-z background). Stacking these populations, we detect the magnification bias effect at 3.3σ and 1.3σ for the low- and high-z backgrounds, respectively. We fit NFW models simultaneously to all observed magnification bias profiles to estimate the multiplicative factor η that describes the ratio of the weak lensing mass to the mass inferred from the SZE observable-mass relation. We further quantify systematic uncertainties in η resulting from the photometric noise and bias, the cluster galaxy contamination and the estimations of the background properties. The resulting η for the combined background populations with 1σ uncertainties is 0.83±0.24(stat)±0.074(sys), indicating good consistency between the lensing and the SZE-inferred masses. We also use our best-fit η to predict the weak lensing shear profiles and compare these predictions with observations, showing agreement between the magnification and shear mass constraints. Our work demonstrates the promise of using the magnification as a complementary method to estimate cluster masses in large surveys.

  11. Detection of enhancement in number densities of background galaxies due to magnification by massive galaxy clusters

    NASA Astrophysics Data System (ADS)

    Chiu, I.; Dietrich, J. P.; Mohr, J.; Applegate, D. E.; Benson, B. A.; Bleem, L. E.; Bayliss, M. B.; Bocquet, S.; Carlstrom, J. E.; Capasso, R.; Desai, S.; Gangkofner, C.; Gonzalez, A. H.; Gupta, N.; Hennig, C.; Hoekstra, H.; von der Linden, A.; Liu, J.; McDonald, M.; Reichardt, C. L.; Saro, A.; Schrabback, T.; Strazzullo, V.; Stubbs, C. W.; Zenteno, A.

    2016-04-01

    We present a detection of the enhancement in the number densities of background galaxies induced from lensing magnification and use it to test the Sunyaev-Zel'dovich effect (SZE-) inferred masses in a sample of 19 galaxy clusters with median redshift z ≃ 0.42 selected from the South Pole Telescope SPT-SZ survey. These clusters are observed by the Megacam on the Magellan Clay Telescope though gri filters. Two background galaxy populations are selected for this study through their photometric colours; they have median redshifts zmedian ≃ 0.9 (low-z background) and zmedian ≃ 1.8 (high-z background). Stacking these populations, we detect the magnification bias effect at 3.3σ and 1.3σ for the low- and high-z backgrounds, respectively. We fit Navarro, Frenk and White models simultaneously to all observed magnification bias profiles to estimate the multiplicative factor η that describes the ratio of the weak lensing mass to the mass inferred from the SZE observable-mass relation. We further quantify systematic uncertainties in η resulting from the photometric noise and bias, the cluster galaxy contamination and the estimations of the background properties. The resulting η for the combined background populations with 1σ uncertainties is 0.83 ± 0.24(stat) ± 0.074(sys), indicating good consistency between the lensing and the SZE-inferred masses. We use our best-fitting η to predict the weak lensing shear profiles and compare these predictions with observations, showing agreement between the magnification and shear mass constraints. This work demonstrates the promise of using the magnification as a complementary method to estimate cluster masses in large surveys.

  12. Primordial Li abundance and massive particles

    SciTech Connect

    Latin-Capital-Letter-Eth apo, H.

    2012-10-20

    The problem of the observed lithium abundance coming from the Big Bang Nucleosynthesis is as of yet unsolved. One of the proposed solutions is including relic massive particles into the Big Bang Nucleosynthesis. We investigated the effects of such particles on {sup 4}HeX{sup -}+{sup 2}H{yields}{sup 6}Li+X{sup -}, where the X{sup -} is the negatively charged massive particle. We demonstrate the dominance of long-range part of the potential on the cross-section.

  13. Massively parallel neurocomputing for aerospace applications

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Barhen, Jacob; Toomarian, Nikzad

    1993-01-01

    An innovative hybrid, analog-digital charge-domain technology, for the massively parallel VLSI implementation of certain large scale matrix-vector operations, has recently been introduced. It employs arrays of Charge Coupled/Charge Injection Device cells holding an analog matrix of charge, which process digital vectors in parallel by means of binary, non-destructive charge transfer operations. The impact of this technology on massively parallel processing is discussed. Fundamentally new classes of algorithms, specifically designed for this emerging technology, as applied to signal processing, are derived.

  14. Prenatal ultrasound diagnosis of massive subchorionic thrombohematoma.

    PubMed

    Richards, D S; Bennett, B B

    1998-05-01

    Massive subchorionic thrombohematoma is a rare condition in which a large maternal blood clot separates the chorionic plate from the villous chorion. This condition is usually complicated by intrauterine growth restriction, and is often associated with fetal distress and perinatal death. We present a case in which the diagnosis of massive subchorionic thrombohematoma was made at 24 weeks' gestation. Doppler ultrasound helped to confirm the diagnosis and demonstrated severely abnormal umbilical blood flow. Two days after the diagnosis, fetal distress prompted emergency Cesarean delivery of a growth-restricted infant. PMID:9644779

  15. Olivier Chesneau's Work on Massive Stars

    NASA Astrophysics Data System (ADS)

    Millour, F.

    2015-12-01

    Olivier Chesneau challenged several fields of observational stellar astrophysics with bright ideas and an impressive amount of work to make them real in the span of his career, from his first paper on P Cygni in 2000, up to his last one on V838 Mon in 2014. He was using all the so-called high-angular resolution techniques since it helped his science to be made, namely study in details the inner structure of the environments around stars, be it small mass (AGBs), more massive (supergiant stars), or explosives (Novae). I will focus here on his work on massive stars.

  16. NON-AQUEOUS DISSOLUTION OF MASSIVE PLUTONIUM

    DOEpatents

    Reavis, J.G.; Leary, J.A.; Walsh, K.A.

    1959-05-12

    A method is presented for obtaining non-aqueous solutions or plutonium from massive forms of the metal. In the present invention massive plutonium is added to a salt melt consisting of 10 to 40 weight per cent of sodium chloride and the balance zinc chloride. The plutonium reacts at about 800 deg C with the zinc chloride to form a salt bath of plutonium trichloride, sodium chloride, and metallic zinc. The zinc is separated from the salt melt by forcing the molten mixture through a Pyrex filter.

  17. Discovering Event Evidence Amid Massive, Dynamic Datasets

    SciTech Connect

    Patton, Robert M; Potok, Thomas E

    2007-01-01

    Automated event extraction remains a very difficult challenge requiring information analysts to manually identify key events of interest within massive, dynamic data. Many techniques for extracting events rely on domain specific natural language processing or information retrieval techniques. As an alternative, this work focuses on detecting events based on identifying event characteristics of interest to an analyst. An evolutionary algorithm is developed as a proof of concept to demonstrate this approach. Initial results indicate that this approach represents a feasible approach to identifying critical event information in a massive data set with no apriori knowledgeof the data set.

  18. Massive proteinuria: a possible side effect of pyrantel pamoate?

    PubMed

    Ferrara, Pietro; Bersani, Iliana; Bottaro, Giorgia; Vitelli, Ottavio; Liberatore, Pio; Gatto, Antonio; del Bufalo, Francesca; Romano, Valerio; Stabile, Achille

    2011-01-01

    Drug-induced renal injury represents a frequent clinical entity. The most common drugs associated with acute tubular necrosis are aminoglycosides, amphotericin B, radiocontrast agents, and cyclosporine, but no data exist about the potential renal toxicity due to anthelmintics administration. Anthelmintics are commonly considered quite safe agents, and side effects such as gastrointestinal, neurologic, hematologic, or hepatic injury have been only rarely described. We report a 4-year-old boy with persistent massive proteinuria without any other symptoms/signs suggesting nephrotic syndrome (NS). The only relevant anamnestic data was the administration of pyrantel pamoate due to oxyuriasis 7 days before the proteinuria development. The patient was affected by NS diagnosed 6 months before and treated with a 12-week course of corticosteroids. During follow-up, carried out at 3 and 6 months after discharge, he did not show further episodes of proteinuria, and no clinical symptoms/signs suggesting a relapse of NS were ever detected. Considering that the proteinuria observed in our patient spontaneously disappeared after 10 days without any treatment, apart from the interruption of the anthelmintic therapy, we would like to alert pediatricians about the possible occurrence of anthelmintics-related renal complications especially among predisposed patients and to perform a watchful waiting not considering the presence of even massive proteinuria as a certain sign of NS relapse. PMID:21500989

  19. Behçet's pulmonary artery aneurysms treated with infliximab and monitored with the 6-min walk test.

    PubMed

    Kotecha, Jalpa; Kamath, Ajay V; Mukhtyar, Chetan

    2016-04-01

    Pulmonary involvement in Behçet's disease (BD) is uncommon; however, it is potentially fatal due to the risk of massive haemoptysis. We describe the case of a 36-year-old male presenting with a 2-month history of worsening dyspnoea, weight loss, haemoptysis, oral ulceration, erythema nodosum and superficial thrombophlebitis. He was diagnosed with pulmonary vasculitis secondary to BD; however, his symptoms were refractory to initial treatment with cyclophosphamide, azathioprine and prednisolone. We therefore trialled infliximab alongside methotrexate, which led to a remarkable improvement in his condition, enabling eventual discontinuation of prednisolone. Whilst not being one of the treatments currently recommended for managing pulmonary involvement in BD, infliximab has previously been successfully used in cases refractory to conventional therapy. We used the 6-min walk test (distance covered and lowest oxygen saturations) to monitor his progress, which correlated with his symptoms. This may represent a useful adjunct in monitoring the activity of pulmonary vasculitis. PMID:27123312

  20. Behçet's pulmonary artery aneurysms treated with infliximab and monitored with the 6-min walk test

    PubMed Central

    Kotecha, Jalpa; Kamath, Ajay V.; Mukhtyar, Chetan

    2016-01-01

    Pulmonary involvement in Behçet's disease (BD) is uncommon; however, it is potentially fatal due to the risk of massive haemoptysis. We describe the case of a 36-year-old male presenting with a 2-month history of worsening dyspnoea, weight loss, haemoptysis, oral ulceration, erythema nodosum and superficial thrombophlebitis. He was diagnosed with pulmonary vasculitis secondary to BD; however, his symptoms were refractory to initial treatment with cyclophosphamide, azathioprine and prednisolone. We therefore trialled infliximab alongside methotrexate, which led to a remarkable improvement in his condition, enabling eventual discontinuation of prednisolone. Whilst not being one of the treatments currently recommended for managing pulmonary involvement in BD, infliximab has previously been successfully used in cases refractory to conventional therapy. We used the 6-min walk test (distance covered and lowest oxygen saturations) to monitor his progress, which correlated with his symptoms. This may represent a useful adjunct in monitoring the activity of pulmonary vasculitis. PMID:27123312

  1. Massive exophytic malignant peripheral nerve sheath tumor.

    PubMed

    Khorsand, Derek; Porrino, Jack; Flaherty, Erin; Bandhlish, Anshu; Davidson, Darin

    2016-06-01

    We present a case of a solitary neurofibroma involving the right posterior shoulder of a 69-year-old man with degeneration into a massive, malignant peripheral nerve sheath tumor measuring more than 3 times the average reported size. The radiographic, magnetic resonance imaging, and computed tomographic features are compared with the gross appearance and pathology. PMID:27257459

  2. Assessment in Massive Open Online Courses

    ERIC Educational Resources Information Center

    Admiraal, Wilfried; Huisman, Bart; Pilli, Olga

    2015-01-01

    Open online distance learning in higher education has quickly gained popularity, expanded, and evolved, with Massive Open Online Courses (MOOCs) as the most recent development. New web technologies allow for scalable ways to deliver video lecture content, implement social forums and track student progress in MOOCs. However, we remain limited in…

  3. Massive Open Online Courses and Economic Sustainability

    ERIC Educational Resources Information Center

    Liyanagunawardena, Tharindu R.; Lundqvist, Karsten O.; Williams, Shirley A.

    2015-01-01

    Millions of users around the world have registered on Massive Open Online Courses (MOOCs) offered by hundreds of universities (and other organizations) worldwide. Creating and offering these courses costs thousands of pounds. However, at present, revenue generated by MOOCs is not sufficient to offset these costs. The sustainability of MOOCs is a…

  4. The Fate of Massive Closed Strings

    SciTech Connect

    Chen Bin; Li Miao; She Jianhuang

    2005-12-02

    We calculate the semi-inclusive decay rate of an average string state with toroidal compactification in the the superstring theory. We also apply this calculation to a brane-inflation model in a warped geometry and find that the decay rate is greatly suppressed if the final strings are both massive and enhanced for massless radiation.

  5. Black Hole Phase Transition in Massive Gravity

    NASA Astrophysics Data System (ADS)

    Ning, Shou-Li; Liu, Wen-Biao

    2016-07-01

    In massive gravity, some new phenomena of black hole phase transition are found. There are more than one critical points under appropriate parameter values and the Gibbs free energy near critical points also has some new properties. Moreover, the Maxwell equal area rule is also investigated and the coexistence curve of the black hole is given.

  6. Interactions in Massive Colliding Wind Binaries

    NASA Technical Reports Server (NTRS)

    Corcoran, M.

    2012-01-01

    The most massive stars (M> 60 Solar Mass) play crucial roles in altering the chemical and thermodynamic properties of their host galaxies. Stellar mass is the fundamental stellar parameter that determines their ancillary properties and which ultimately determines the fate of these stars and their influence on their galactic environs. Unfortunately, stellar mass becomes observationally and theoretically less well constrained as it increases. Theory becomes uncertain mostly because very massive stars are prone to strong, variable mass loss which is difficult to model. Observational constraints are uncertain too. Massive stars are rare, and massive binary stars (needed for dynamical determination of mass) are rarer still: and of these systems only a fraction have suitably high orbital inclinations for direct photometric and spectroscopic radial-velocity analysis. Even in the small number of cases in which a high-inclination binary near the upper mass limit can be identified, rotational broadening and contamination of spectral line features from thick circumstellar material (either natal clouds or produced by strong stellar wind driven mass loss from one or both of he stellar components) biases the analysis. In the wilds of the upper HR diagram, we're often left with indirect and circumstantial means of determining mass, a rather unsatisfactory state of affairs.

  7. Embeddings of the "New Massive Gravity"

    NASA Astrophysics Data System (ADS)

    Dalmazi, D.; Mendonça, E. L.

    2016-07-01

    Here we apply different types of embeddings of the equations of motion of the linearized "New Massive Gravity" in order to generate alternative and even higher-order (in derivatives) massive gravity theories in D=2+1. In the first part of the work we use the Weyl symmetry as a guiding principle for the embeddings. First we show that a Noether gauge embedding of the Weyl symmetry leads to a sixth-order model in derivatives with either a massive or a massless ghost, according to the chosen overall sign of the theory. On the other hand, if the Weyl symmetry is implemented by means of a Stueckelberg field we obtain a new scalar-tensor model for massive gravitons. It is ghost-free and Weyl invariant at the linearized level around Minkowski space. The model can be nonlinearly completed into a scalar field coupled to the NMG theory. The elimination of the scalar field leads to a nonlocal modification of the NMG. In the second part of the work we prove to all orders in derivatives that there is no local, ghost-free embedding of the linearized NMG equations of motion around Minkowski space when written in terms of one symmetric tensor. Regarding that point, NMG differs from the Fierz-Pauli theory, since in the latter case we can replace the Einstein-Hilbert action by specific f(R,Box R) generalizations and still keep the theory ghost-free at the linearized level.

  8. Young Massive Clusters in the Galactic Center

    NASA Astrophysics Data System (ADS)

    Figer, D. F.

    2004-12-01

    The three young clusters in the Galactic Center represent the closest examples of massive starbursts and they define the upper mass limit of the Galactic cluster mass functions. In this review, I describe the characteristics and content of the Arches, Quintuplet, and Central clusters. They each are more massive than any other cluster in the Galaxy, and the Arches cluster, in particular, has a mass and age that make it ideal for studies of massive stellar evolution and dense stellar systems. A preliminary measurement indicates that the initial mass function in the Galactic center is top-heavy, suggesting an environmental effect that has otherwise been absent in similar observations for Galactic clusters. Given the relatively more evolved nature of the Quintuplet and Central clusters, these clusters contain stars in a wide range of evolutionary states, including Luminous Blue Variables and Wolf-Rayet stars. The Quintuplet cluster provides a particularly interesting view of the most massive stars that are known, the Pistol Star and FMM362. An analysis of the mass spectrum in the Arches cluster suggests an upper mass cutoff of ˜150-200 M⊙.

  9. How I treat patients with massive hemorrhage.

    PubMed

    Johansson, Pär I; Stensballe, Jakob; Oliveri, Roberto; Wade, Charles E; Ostrowski, Sisse R; Holcomb, John B

    2014-11-13

    Massive hemorrhage is associated with coagulopathy and high mortality. The transfusion guidelines up to 2006 recommended that resuscitation of massive hemorrhage should occur in successive steps using crystalloids, colloids, and red blood cells (RBCs) in the early phase and plasma and platelets in the late phase. With the introduction of the cell-based model of hemostasis in the mid-1990s, our understanding of the hemostatic process and of coagulopathy has improved. This has contributed to a change in resuscitation strategy and transfusion therapy of massive hemorrhage along with an acceptance of the adequacy of whole blood hemostatic tests to monitor these patients. Thus, in 2005, a strategy aiming at avoiding coagulopathy by proactive resuscitation with blood products in a balanced ratio of RBC:plasma:platelets was introduced, and this has been reported to be associated with reduced mortality in observational studies. Concurrently, whole blood viscoelastic hemostatic assays have gained acceptance by allowing a rapid and timely identification of coagulopathy along with enabling an individualized, goal-directed transfusion therapy. These strategies joined together seem beneficial for patient outcome, although final evidence on outcome from randomized controlled trials are lacking. We present how we in Copenhagen and Houston, today, manage patients with massive hemorrhage. PMID:25293771

  10. A Taxonomy of Massive Open Online Courses

    ERIC Educational Resources Information Center

    Pilli, Olga; Admiraal, Wilfried

    2016-01-01

    Massive Open Online Courses (MOOCs) as a new approach to distance education, which originated from the open education resources (OER) movement, are becoming widespread throughout the world. Over time, early versions of cMOOCs have undergone changes in terms of use, name and structure. In their short life, MOOCs have been categorized into different…

  11. Modeling populations of rotationally mixed massive stars

    NASA Astrophysics Data System (ADS)

    Brott, I.

    2011-02-01

    Massive stars can be considered as cosmic engines. With their high luminosities, strong stellar winds and violent deaths they drive the evolution of galaxies through-out the history of the universe. Despite the importance of massive stars, their evolution is still poorly understood. Two major issues have plagued evolutionary models of massive stars until today: mixing and mass loss On the main sequence, the effects of mass loss remain limited in the considered mass and metallicity range, this thesis concentrates on the role of mixing in massive stars. This thesis approaches this problem just on the cross road between observations and simulations. The main question: Do evolutionary models of single stars, accounting for the effects of rotation, reproduce the observed properties of real stars. In particular we are interested if the evolutionary models can reproduce the surface abundance changes during the main-sequence phase. To constrain our models we build a population synthesis model for the sample of the VLT-FLAMES Survey of Massive stars, for which star-formation history and rotational velocity distribution are well constrained. We consider the four main regions of the Hunter diagram. Nitrogen un-enriched slow rotators and nitrogen enriched fast rotators that are predicted by theory. Nitrogen enriched slow rotators and nitrogen unenriched fast rotators that are not predicted by our model. We conclude that currently these comparisons are not sufficient to verify the theory of rotational mixing. Physical processes in addition to rotational mixing appear necessary to explain the stars in the later two regions. The chapters of this Thesis have been published in the following Journals: Ch. 2: ``Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones'', I. Brott, S. E. de Mink, M. Cantiello, N. Langer, A. de Koter, C. J. Evans, I. Hunter, C. Trundle, J.S. Vink submitted to Astronomy & Astrop hysics Ch. 3: ``The VLT-FLAMES Survey of Massive

  12. Placing Observational Constraints on Massive Star Models

    NASA Astrophysics Data System (ADS)

    Rosenfield, Philip

    2011-10-01

    The lives and deaths of massive stars are intricately linked to the evolution of galaxies. Yet, despite their integral importance to understanding galaxy evolution, models of massive stars are inconsistent with observations. These uncertainties can be traced to limited observational constraints available for improving massive star models. A sensitive test of the underlying physics of massive stars, e.g., convection, rotation, and mass loss is to measure the ratio of blue core helium burning stars {BHeB} to red core helium burning stars {RHeB}, 5-20Msun stars in the stage evolution immediately following the main sequence. Even the most sophisticated models cannot accurately predict the observed ratio over a range of metallicities, suggesting an insufficient understanding of the underlying physics. However, observational measurements of this ratio over a wide range of environments would provide substantial constraints on the physical parameters governing the evolution of all stars >5 Msun.We propose to place stringent observational constraints on the physics of massive star evolution by uniformly measuring the B/R HeB ratio in a wide range of galaxies. The HST archive contains high quality optical imaging of resolved stellar populations of dozens of nearby galaxies. From the ANGST program, we identified 38 galaxies, spanning 2 dex in metallicity that have significant BHeB and RHeB populations. Using this sample, we will empirically characterize the colors of the BHeB and RHeB sequences as a function of luminosity and metallicity, measure the B/R ratio, and constrain the lifetimes of the BHeB and RHeBs in the Padova stellar evolution models and the Cambridge STARS code.

  13. Cosmic Magnetic Fields from Torsion Modes and Massive Photon Inflation

    NASA Astrophysics Data System (ADS)

    Garcia de Andrade, L. C.

    2014-09-01

    Earlier Barrow & Tsagas (2008) showed that a slower decay of magnetic fields are present in open Friedmann universes, with traditional Maxwell equations. In their paper magnetic fields of the order of B˜10-33 G which are far below the value required to seed galactic dynamos were obtained. In this paper galactic dynamo seeds of the order of B˜10-23 G are obtained from massive electrodynamics in Einstein-Cartan-Proca (ECP) expanding universe of de Sitter type. Slow decay of magnetic fields in photon-torsion coupling in QED (Garcia de Andrade 2011b) have been recently shown by Garcia de Andrade (2012) also not be able to seed galactic dynamos. Torsion modes are constrained by the field equations. Space-time torsion is shown to be explicitly responsible for the slow decay of cosmic magnetic field. In the absence of massive photon torsion coupling the magnetic field decay is of the order B˜t-3/2, while when torsion is turn on B˜t-1.2. The pure massive-photon-torsion contribution amplifies the magnetic field by Btorsion˜t0.1 which characterizes an extremely slow magnetic dynamo action due to purely torsion gravitational effects. Recently, Barrow et al. (2012) have obtained superadiabatic amplification of B-fields in the Friedmann open cosmology which lies within 10-20 G and 10-12 G which falls very comfortable within limits to seed galactic dynamos. Other simple solutions where B-field decays as B˜a-1, relatively weak photon-torsion coupling approximation. These solutions are obtained for the de Sitter and Friedmann metrics.

  14. The size of stellar reactors and rotational mixing of nuclear elements in massive stars

    NASA Astrophysics Data System (ADS)

    Maeder, Andre

    On the basis of observations for 25 young associations, evidence is presented for overshooting in massive stars, and a typical value is derived for the overshooting distance: d(over) = (0.25-0.30)Hp where Hp is the pressure scale height at the edge of the classical core. Turbulent diffusion of nuclear elements due to rotational mixing appears to be very efficient in massive stars because of their high radiative viscosity. A bifurcation occurs in stellar evolution. Below some rotation, evolution is essentially classical; above it, mixing is very efficient and produces essentially blueward homogeneous evolution.

  15. Two Cases of Ileal Dieulafoy Lesion with Massive Hematochezia Treated by Single Balloon Enteroscopy

    PubMed Central

    Choi, Young Chul; Park, Sang Hyun; Kwon, Kye Sook; Kim, Hyung Gil; Shin, Yong Woon

    2012-01-01

    Ileal Dieulafoy lesion is an unusual vascular abnormality that can cause gastrointestinal bleeding. It can be associated with massive, life-threatening hemorrhage and requires urgent angiographic intervention or surgery. Ileal Dieulafoy lesion is hard to recognize due to inaccessibility and normal-appearing mucosa. With advances in endoscopy, aggressive diagnostic and therapeutic approaches including enteroscopy have recently been performed for small bowel bleeding. We report two cases of massive ileal Dieulafoy lesion bleeding diagnosed and treated successfully by single balloon enteroscopy with a review of the literature. PMID:23251897

  16. Nearby regions of massive star formation

    NASA Astrophysics Data System (ADS)

    Bally, John; Cunningham, Nathaniel; Moeckel, Nickolas; Smith, Nathan

    Observations of the nearest regions of massive star formation such as Orion are reviewed. Early-type stars in the local OB associations, as well as their superbubbles and supershells provide a fossil record of massive star birth in the Solar vicinity over about the last 40 Myr. This record shows that most massive stars are born from dense, high-pressure, hot cores which spawn transient clusters that dissipate into the field soon after formation. A large fraction (15 to 30%) of massive stars are high-velocity runaways moving at more than 20 km s^{-1}. High-mass stars have a larger companion fraction than their lower-mass siblings. The Orion star forming complex contains the nearest site of on-going massive star formation. Studies of the Orion Nebula and the dense molecular cloud core located immediately behind the HII region provide our sharpest view of massive star birth. This region has formed a hierarchy of clusters within clusters. The Trapezium, OMC-1S, and OMC-1 regions represent three closely spaced sub-clusters within the more extended Orion Nebula Cluster. The oldest of these sub-clusters, which consists of the Trapezium stars, has completely emerged from its natal core. The OMC-1S and OMC-1 regions, are still highly embedded and forming clusters of additional moderate and high mass stars. Over a dozen YSOs embedded in OMC-1S are driving jets and outflows, many of which are injecting energy and momentum into the Orion Nebula. Recent proper motion measurements indicate that the Becklin-Neugebauer object is a high-velocity star moving away from the OMC1 core with a velocity of 30 km s^{-1}, making it the youngest high-velocity star known. Source I may be moving in the opposite direction with a velocity of about 12 km s^{-1}. The projected separation between source I and BN was less than few hundred AU about 500 years ago. The spectacular bipolar molecular outflow and system of shock-excited H_2 fingers emerging from OMC-1 has a dynamical age of about 1100

  17. SUPERDENSE MASSIVE GALAXIES IN WINGS LOCAL CLUSTERS

    SciTech Connect

    Valentinuzzi, T.; D'Onofrio, M.; Fritz, J.; Poggianti, B. M.; Bettoni, D.; Fasano, G.; Moretti, A.; Omizzolo, A.; Varela, J.; Cava, A.; Couch, W. J.; Dressler, A.; Moles, M.; Kjaergaard, P.; Vanzella, E.

    2010-03-20

    Massive quiescent galaxies at z > 1 have been found to have small physical sizes, and hence to be superdense. Several mechanisms, including minor mergers, have been proposed for increasing galaxy sizes from high- to low-z. We search for superdense massive galaxies in the WIde-field Nearby Galaxy-cluster Survey (WINGS) of X-ray selected galaxy clusters at 0.04 < z < 0.07. We discover a significant population of superdense massive galaxies with masses and sizes comparable to those observed at high redshift. They approximately represent 22% of all cluster galaxies more massive than 3 x 10{sup 10} M{sub sun}, are mostly S0 galaxies, have a median effective radius (R{sub e} ) = 1.61 +- 0.29 kpc, a median Sersic index (n) = 3.0 +- 0.6, and very old stellar populations with a median mass-weighted age of 12.1 +- 1.3 Gyr. We calculate a number density of 2.9 x 10{sup -2} Mpc{sup -3} for superdense galaxies in local clusters, and a hard lower limit of 1.3 x 10{sup -5} Mpc{sup -3} in the whole comoving volume between z = 0.04 and z = 0.07. We find a relation between mass, effective radius, and luminosity-weighted age in our cluster galaxies, which can mimic the claimed evolution of the radius with redshift, if not properly taken into account. We compare our data with spectroscopic high-z surveys and find that-when stellar masses are considered-there is consistency with the local WINGS galaxy sizes out to z {approx} 2, while a discrepancy of a factor of 3 exists with the only spectroscopic z > 2 study. In contrast, there is strong evidence for a large evolution in radius for the most massive galaxies with M{sub *} > 4 x 10{sup 11} M{sub sun} compared to similarly massive galaxies in WINGS, i.e., the brightest cluster galaxies.

  18. Mass-varying massive gravity with k-essence

    NASA Astrophysics Data System (ADS)

    Tannukij, Lunchakorn; Wongjun, Pitayuth

    2016-01-01

    For a large class of mass-varying massive-gravity models, the graviton mass cannot provide the late-time cosmic expansion of the universe due to its vanishing at late time. In this work, we propose a new class of mass-varying massive gravity models, in which the graviton mass varies according to a kinetic term of a k-essence field. By using a more general form of the fiducial metric, we found a solution such that a non-vanishing graviton mass can drive the accelerated expansion of the universe at late time. We also perform dynamical analyses of such a model and find that without introducing the k-essence Lagrangian, the graviton mass can be responsible for both dark contents of the universe, namely dark energy, which drives the accelerated expansion of the universe, and non-relativistic matter, which plays the role of dark matter. Moreover, by including the k-essence Lagrangian, we find that it is possible to alleviate the so-called cosmic coincidence problem.

  19. Evidence for a bifurcation in massive star evolution

    NASA Astrophysics Data System (ADS)

    Maeder, Andre

    1986-07-01

    The effects of rotationally induced mixing on the evolution of massive stars is examined. Models show that, due to the high radiative viscosity, the diffusion coefficient is sufficiently large to mix most massive stars during their MS lifetime. However, below a critical rotation velocity, diffusive mixing is efficiently prevented by the mu-gradient. A wide bifurcation appears in the evolutionary tracks. Below critical rotation, the evolution is essentially classical with unmodified redwards tracks in the HR diagram. Above critical rotation, the evolutionary tracks go upwards and bluewards, very close to those of fully homogeneous evolution. In this case the model composition is rapidly characterized by He and N enrichments, C and O depletions. The homogeneous models lead to the formation of WR stars before the end of the H-burning phase, which increases the WR lifetime; there is probably no WNE stage in this homogeneous evolutionary scheme. For the classically evolving stars, diffusion may increase the size of the convective core as overshooting does; diffusion may also produce moderate changes of the surface C/N and O/N ratios.

  20. The performance realities of massively parallel processors: A case study

    SciTech Connect

    Lubeck, O.M.; Simmons, M.L.; Wasserman, H.J.

    1992-07-01

    This paper presents the results of an architectural comparison of SIMD massive parallelism, as implemented in the Thinking Machines Corp. CM-2 computer, and vector or concurrent-vector processing, as implemented in the Cray Research Inc. Y-MP/8. The comparison is based primarily upon three application codes that represent Los Alamos production computing. Tests were run by porting optimized CM Fortran codes to the Y-MP, so that the same level of optimization was obtained on both machines. The results for fully-configured systems, using measured data rather than scaled data from smaller configurations, show that the Y-MP/8 is faster than the 64k CM-2 for all three codes. A simple model that accounts for the relative characteristic computational speeds of the two machines, and reduction in overall CM-2 performance due to communication or SIMD conditional execution, is included. The model predicts the performance of two codes well, but fails for the third code, because the proportion of communications in this code is very high. Other factors, such as memory bandwidth and compiler effects, are also discussed. Finally, the paper attempts to show the equivalence of the CM-2 and Y-MP programming models, and also comments on selected future massively parallel processor designs.

  1. An analysis of characteristics in nonlinear massive gravity

    NASA Astrophysics Data System (ADS)

    Izumi, Keisuke; Ong, Yen Chin

    2013-09-01

    We study the Cauchy problem in a special case of nonlinear massive gravity. Despite being ghost free, it has recently been argued that the theory is inherently problematic due to the existence of superluminal shock waves. Furthermore, it is claimed that an acausal characteristic can arise for any choice of background. In order to further understand the causal structure of the theory, we carefully perform a detailed analysis of the characteristic equations and show that the theory does admit a well-posed Cauchy problem, i.e., there exists hypersurfaces that are not a characteristic hypersurface. Puzzles remain regarding the existence of a superluminal propagating mode in both the minimal ghost-free theory that we analyzed, as well as in the full nonlinear massive gravity. That is, our result should not be taken as any indication of the healthiness of the theory. We also give a detailed review of Cauchy-Kovalevskaya theorem and its application in the appendix, which should be useful for investigating causal structures of other theories of gravity.

  2. Hamiltonian approach to the lattice massive Schwinger model

    SciTech Connect

    Sidorov, A.V.; Zastavenko, L.G.

    1996-08-01

    The authors consider the limit e{sup 2}/m{sup 2} {much_lt} 1 of the lattice massive Schwinger model, i.e., the lattice massive QED in two space-time dimensions, up to lowest order in the effective coupling constant e{sup 2}/m{sup 2}. Here, m is the fermion mass parameter and e is the electron charge. They compare their lattice QED model with the analogous continuous space and lattice space models, (CSM and LSM), which do not take account of the zero momentum mode, z.m.m., of the vector potential. The difference is that (due to extra z.m.m. degree of freedom) to every eigenstate of the CSM and LSM there corresponds a family of eigenstates of the authors lattice QED with the parameter {lambda}. They restrict their consideration to small values of the parameter {lambda}. Then, the energies of the particle states of their lattice QED and LSM do coincide (in their approximation). In the infinite periodicity length limit the Hamiltonian of the authors lattice QED (as well as the Hamiltonian of the LSM) possesses two different Hilbert spaces of eigenfunctions. Thus, in this limit the authors lattice QED model (as well as LSM) describes something like two connected, but different, worlds.

  3. Dynamic Star Formation in the Massive DR21 Filament

    SciTech Connect

    Schneider, N.; Csengeri, T.; Bontemps, S.; Motte, F.; Simon, R.; Hennebelle, P.; Federrath, C.; Klessen, R.; /ZAH, Heidelberg /KIPAC, Menlo Park

    2010-08-25

    The formation of massive stars is a highly complex process in which it is unclear whether the star-forming gas is in global gravitational collapse or an equilibrium state supported by turbulence and/or magnetic fields. By studying one of the most massive and dense star-forming regions in the Galaxy at a distance of less than 3 kpc, i.e. the filament containing the well-known sources DR21 and DR21(OH), we attempt to obtain observational evidence to help us to discriminate between these two views. We use molecular line data from our {sup 13}CO 1 {yields} 0, CS 2 {yields} 1, and N{sub 2}H{sup +} 1 {yields} 0 survey of the Cygnus X region obtained with the FCRAO and CO, CS, HCO{sup +}, N{sub 2}H{sup +}, and H{sub 2}CO data obtained with the IRAM 30m telescope. We observe a complex velocity field and velocity dispersion in the DR21 filament in which regions of the highest column-density, i.e., dense cores, have a lower velocity dispersion than the surrounding gas and velocity gradients that are not (only) due to rotation. Infall signatures in optically thick line profiles of HCO{sup +} and {sup 12}CO are observed along and across the whole DR21 filament. By modelling the observed spectra, we obtain a typical infall speed of {approx}0.6 km s{sup -1} and mass accretion rates of the order of a few 10{sup -3} M{sub {circle_dot}} yr{sup -1} for the two main clumps constituting the filament. These massive clumps (4900 and 3300 M{sub {circle_dot}} at densities of around 10{sup 5} cm{sup -3} within 1 pc diameter) are both gravitationally contracting. The more massive of the clumps, DR21(OH), is connected to a sub-filament, apparently 'falling' onto the clump. This filament runs parallel to the magnetic field. Conclusions. All observed kinematic features in the DR21 filament (velocity field, velocity dispersion, and infall), its filamentary morphology, and the existence of (a) sub-filament(s) can be explained if the DR21 filament was formed by the convergence of flows on large

  4. Massive stars and expanding shells within the violent interstellar medium

    NASA Astrophysics Data System (ADS)

    Thilker, David Allan

    Massive stars have a tremendous impact on their surroundings, largely due to a prodigious production rate of Lyman continuum photons and their inevitable termination in a supernova explosion. A single OB star may ionize a sufficiently luminous HII region to remain detectable out to distances of many Mpc. By concentrating the mechanical power of many high mass stars in a limited volume over a short time period, OB associations are known to produce large expanding bubbles in the interstellar medium (ISM). Aperture synthesis observations of HI in nearby galaxies clearly reveal the bubbly character of the diffuse ISM and highlight the connection with massive stars. In this dissertation I close the loop between theory and observations regarding massive stars, their incipient HII regions, and related expanding shells, all in the hope of learning more about the diffuse ISM. The research described herein has three main components: (1)object recognition in the context of HI datacubes and hydrodynamic shell models, (2)automated photometry of HII regions in crowded narrowband images, and (3)population synthesis modeling of stellar clusters and expanding shells in disk galaxies. I have created efficient procedures for conducting a census of HI superbubbles and young massive star clusters in nearby galaxies, plus a modeling framework allowing one to check these databases for relative agreement. My population synthesis algorithm predicts ensemble characteristics: of a disk-galaxy shell population, given details of the stellar cluster formation process and global properties of the galaxy in question. My automated HI object recognition method has made possible the Las Cruces/Dwingeloo Supershell Survey (LCDSS) of 21 nearby disk galaxies. In this dissertation I present early LCDSS results for NGC 300, NGC 2403, M81, and M101. Furthermore, I demonstrate the technique for photometry of HII regions by analyzing a small sample of 11 prominent spirals. The photometric measurements are

  5. Tracheobronchial injury due to blunt chest trauma.

    PubMed

    Mahmodlou, Rahim; Sepehrvand, Nariman

    2015-01-01

    Tracheobronchial avulsion resulting from blunt trauma is a very rare and serious condition, mostly due to high-speed traffic crashes. In this article, we briefly report the case of an 18-year-old man who was injured in a car accident and because of massive persistent air leakage (despite appropriate chest tube drainage), deemed to have a deep tracheobronchial injury. Due to a rapid drop in the patient's O2 saturation, he underwent an anterolateral thoracotomy. Endotracheal intubation was performed under direct visualization. The right mainstem bronchus was disrupted from the carina with a 1.5-cm stump remaining on the carina, and the remainder was crushed to the origin of the right superior lobe bronchus. Hence, a right superior lobectomy was performed and the postoperative course was uneventful. PMID:26157657

  6. The X-ray halos of the most MASSIVE galaxies in the Universe

    NASA Astrophysics Data System (ADS)

    Goulding, Andy D.; Greene, Jenny E.; Ma, Chung-Pei; McConnell, Nicholas J.; Blakeslee, John; Bogdan, Akos; Thomas, Jens

    2016-01-01

    Despite decades of research, the assembly history and evolution of the most massive elliptical galaxies in the Universe remains mysterious. The physical properties (gas temperatures, halo masses, stellar kinematics etc.) of local elliptical galaxies are now being probed in depth by studies such as Atlas3D. However, due to their limited volume, these studies still do not include the most massive galaxies. Here I will present our investigation of the X-ray and optical properties of a complete sample of M > 1011 M⊙ sources within the MASSIVE Galaxy Survey (Ma et al. 2014), extending the previous Atlas3D analyses by an order of magnitude in K-band luminosity. We harness the exquisite spatial resolution and sensitivity of the Chandra X-ray observatory, combined with integral field optical spectroscopy, to provide the most complete and unbiased picture, to date, for the effect of large and small scale environment on the evolution of elliptical galaxies.

  7. Luminous Infrared Sources in the Local Group: Identifying the Missing Links in Massive Star Evolution

    NASA Astrophysics Data System (ADS)

    Britavskiy, N.; Bonanos, A. Z.; Mehner, A.

    2015-01-01

    We present the first systematic survey of dusty massive stars (RSGs, LBVs, sgB[e]) in nearby galaxies, with the goal of understanding their importance in massive star evolution. Using the fact that these stars are bright in mid-infrared colors due to dust, we provide a technique for selecting and identifying dusty evolved stars based on the results of Bonanos et al. (2009, 2010), Britavskiy et al. (2014), and archival Spitzer/IRAC photometry. We present the results of our spectroscopic follow-up of luminous infrared sources in the Local Group dwarf irregular galaxies: Pegasus, Phoenix, Sextans A and WLM. The survey aims to complete the census of dusty massive stars in the Local Group.

  8. First Spectroscopic Identification of Massive Young Stellar Objects in the Galactic Center

    NASA Technical Reports Server (NTRS)

    An, Deokkeun; Ramirez, V.; Sellgren, Kris; Arendt, Richard G.; Boogert, A. C.; Schultheis, Mathias; Stolovy, Susan R.; Cotera, Angela S.; Robitaille, Thomas P.; Smith, Howard A.

    2009-01-01

    We report the detection of several molecular gas-phase and ice absorption features in three photometrically-selected young stellar object (YSO) candidates in the central 280 pc of the Milky Way. Our spectra, obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope, reveal gas-phase absorption from CO2 (15.0 microns), C2H2 (13.7 microns) and HCN (14.0 microns). We attribute this absorption to warm, dense gas in massive YSOs. We also detect strong and broad 15 microns CO2 ice absorption features, with a remarkable double-peaked structure. The prominent long-wavelength peak is due to CH3OH-rich ice grains, and is similar to those found in other known massive YSOs. Our IRS observa.tions demonstra.te the youth of these objects, and provide the first spectroscopic identification of massive YSOs in the Galactic Center.

  9. The most massive MaxBCG clusters

    NASA Astrophysics Data System (ADS)

    Murray, Stephen

    2014-09-01

    Great progress on galaxy clusters has been made in the last several years with SZ and optical surveys. Some new puzzles also emerged and one of them is the mismatch between the stacked Planck SZ fluxes and the model expectations for the MaxBCG clusters. While previous studies regarding this puzzle require the calibration of the true mass and the standard pressure template, we bypass the intermediate steps to directly compare the pressure content derived from the X-ray data with the SZ flux, for massive MaxBCG clusters. This proposal requests Chandra data for 3 clusters to complete a sample of 12 most massive MaxBCG clusters observed with either XMM or Chandra. The results will shed light on the mismatch puzzle and constrain the important scaling relations like Y_X - N_200 and Y_X - Y_SZ.

  10. Identifying new massive stars in Carina

    NASA Astrophysics Data System (ADS)

    Alexander, Michael J.; McSwain, M. Virginia; Povich, Matthew S.; Hanes, Richard J.

    2015-01-01

    We have conducted an optical and infrared spectroscopic survey of 94 candidate OB stars in the Great Carina Nebula. Candidates were selected on the basis of their infrared spectral energy distributions, which was used to estimate bolometric luminosity and effective temperature. Additionally, the presence of X-ray emission -- a sign of young, dynamic atmospheres -- was used to increase the likelihood of selecting newly formed massive stars associated with the Carina star formation region. Here, we present the preliminary results of this study including spectral types and the OB star confirmation rate. We also discuss the spatial distribution of the new OB stars with respect to the various clusters and sub-clusters and speculate on the implications of additional massive stars on the global mass function of the Carina star forming complex.