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Sample records for massive haemoptysis due

  1. Bronchial arterial embolisation for massive haemoptysis in cavitary sarcoidosis

    PubMed Central

    Loh, Geoffrey Andrew; Lettieri, Christopher J; Shah, Anita A

    2013-01-01

    A 48-year-old non-smoking man with a 6-year history of pulmonary cavitary sarcoidosis presented with acute onset of haemoptysis of approximately 600 ml. Prior episodes of haemoptysis had resolved only after serial upper lobe wedge resections bilaterally and steroids. A chest CT identified bilateral upper lobe cavitary lesions with extravasation of contrast from a large right upper lobe cavity. The patient underwent urgent bronchial angiography and subsequent bronchial artery embolisation of a left bronchial artery and three right bronchial arteries. He was started on methotrexate and steroids for refractory sarcoidosis. Two years after embolisation, the patient remained haemoptysis-free with his sarcoid well controlled on methotrexate monotherapy. PMID:23355590

  2. A 30-year-old pregnant patient with massive haemoptysis and influenza A: Atypical presentation of a common pathogen

    PubMed Central

    Nguyen, Philippe; Weber, Florence

    2013-01-01

    A 30-year-old woman presented at 19 weeks of gestation with symptoms of sore throat, rhinorrhea and haemoptysis that progressed to massive haemoptysis. Her medical history included asthma and a history of smoking prior to pregnancy. Investigations revealed no obvious cause of bleeding. Right lower lobe lobectomy was performed, given the suspicion of a lesion within the intermediate bronchus. The patient developed adult respiratory distress syndrome around 36 h postoperatively. Polymerase chain reaction testing on bronchoalveolar lavage samples was positive for influenza A. Therapy with oseltamivir was initiated. She was discharged two weeks later. This is a rare case of a severe complication from seasonal interpandemic influenza during pregnancy, which underscores the importance of immunization for pregnant women.

  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 Central

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

    2016-01-01

    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. Does tranexamic acid stop haemoptysis?

    PubMed Central

    Moen, Christian Arvei; Burrell, Amy; Dunning, Joel

    2013-01-01

    A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was ‘Does tranexamic acid stop haemoptysis’? Altogether 49 papers were found using the reported search strategy, of which 13 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. This consisted of one systematic review including a meta-analysis of two double-blind randomized controlled trials (RCTs), the two RCTs, one cohort study, two case-series and seven case reports. Main outcomes included bleeding time, bleeding volume and occurrence of thromboembolic complications after start of treatment. Based on results from the meta-analysis, no difference in remission of bleeding within 1 week was found between tranexamic acid (TA) and placebo groups (odds ratio 1.56, 95% CI: 0.44–5.46). However, overall bleeding time was significantly shorter for the TA group (weighted mean difference −19.47, 95% CI: −26.90, −12.03 h). In one RCT, TA reduced both the duration and the volume of bleeding compared with patients receiving placebo (both P < 0.0005). However, the other RCT failed to find a difference in bleeding time (P = 0.2). In these studies, no patient suffered from thromboembolic complications. Two case reports, however, describe development of pulmonary embolism during TA treatment. Several case reports on the use of TA for treatment of haemoptysis secondary to cystic fibrosis were found. In general, they suggest that TA may be a useful and well-tolerated medication for the treatment of intractable haemoptysis in this patient group. We conclude that limited research on the use of TA for treatment of haemoptysis exists. As aetiology of haemoptysis as well as length of treatment, dosage and form of TA administration varied between the studies, strong recommendations are difficult to give

  6. Bronchial haemangioma: exceptionally rare cause of haemoptysis.

    PubMed

    Jennings, Scott; Tharion, John; Jones, Peter; Brown, Michael

    2013-12-01

    Bronchial haemangioma is an exceptionally rare cause of haemoptysis in the adult. There are currently less than 10 recorded cases in the literature. Airway haemangiomas are generally seen in infants with coexistent cutaneous haemangiomas. The incidence of bronchial haemangioma in adults remains unknown. This case reports the diagnosis and treatment of a bronchial haemangioma in a 56 year-old male presenting with a one-month history of haemoptysis. Bronchial haemangioma diagnosis was confirmed and excision performed by bronchoscopy without complication. Bronchial haemangioma should be a considered differential diagnosis in the presence of meaningful haemoptysis when an endoluminal lesion is visualised on computed tomography scan. This case also demonstrates that bronchial haemangiomas can be successfully removed via bronchoscopy with minimal risk and discomfort to the patient.

  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.

  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. 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.

  10. Haemoptysis as a primary manifestation of cryptogenic organizing pneumonia (COP).

    PubMed

    Chatzivasiloglou, Fotini; Katsenos, Stamatis; Psathakis, Konstantinos; Tsintiris, Konstantinos

    2015-01-01

    Cryptogenic organizing pneumonia (COP), previously called bronchiolitis obliterans organizing pneumonia (BOOP) is a clinicopathological disorder of unknown aetiology but increasingly reported. It usually presents with symptoms of dyspnea, cough, fever, weight loss accompanied by the presence of alveolar opacities on chest radiograph. Haemoptysis, described as blood streaking has only rarely been reported as primary presentation of COP. Herein, we report a case of COP in which submassive haemoptysis was the main clinical manifestation. The clinical, radiological, pathological, and therapeutic aspects of the disease are briefly discussed. Cryptogenic organizing pneumonia should be taken into consideration in the differential diagnosis of severe haemoptysis. PMID:27451594

  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. [Massive alveolar hemorrhage due to cytomegalovirus (CMV) and HIV infection].

    PubMed

    Cortés, A; Peña, E; Vega, R; Reyes, G; Bautista, E

    2011-03-01

    Alveolar hemorrhage may be a complication of diseases with local and systemic manifestations. Both share the same pathophysiological concept: damage to the alveolar microcirculation. It is a clinical entity that generates a diagnostic challenge for the physician. Early recognition favors aggressive treatment, which can improve the outcome. Despite the technological advances in its diagnosis and treatment, it is still a condition having high morbidity and mortality. We present the case of a 42-year old woman diagnosed of massive alveolar hemorrhage induced by cytomegalovirus (CMV) and HIV infection. Its presentation is atypical because most reported cases have occurred as a pneumonic process, episodes of massive hemorrhage being uncommon. The diagnosis was documented by bronchoscopy with bronchoalveolar lavage and etiological diagnosis with molecular techniques using reverse transcription polymerase chain reaction.

  13. Pulmonary cavitary lesion and haemoptysis: rare aetiology on biopsy.

    PubMed

    Kim, John; Thomashow, Byron; Saqi, Anjali

    2016-01-01

    Pleomorphic carcinoma of the lung is a rare form of malignancy that can present similarly to other necrotising cavitary lung diseases. We present a case of a Caucasian woman who presented with recurrent haemoptysis and a right upper lobe cavitary lesion on CT scan. She underwent selective embolisation of the right bronchial artery by interventional radiology to control her haemoptysis. Positron emission tomography/CT scan was performed which showed significant fluorodeoxyglucose uptake in the right upper lobe cavitary lesion. There was a discussion among her providers about the aetiology of this lesion including infection and malignancy. Cultures from bronchoalveolar lavage and blood were negative for infection as the patient underwent right upper lobectomy which showed invasive sarcomatoid pleomorphic carcinoma with a minor component of acinar adenocarcinoma. She was diagnosed with stage IB (T2aN0M0) sarcomatoid pleomorphic carcinoma and underwent adjuvant chemotherapy after her lobectomy with recurrence and metastasis to her stomach and pancreas. PMID:27507695

  14. Haemoptysis in adults: a 5-year study using the French nationwide hospital administrative database.

    PubMed

    Abdulmalak, Caroline; Cottenet, Jonathan; Beltramo, Guillaume; Georges, Marjolaine; Camus, Philippe; Bonniaud, Philippe; Quantin, Catherine

    2015-08-01

    Haemoptysis is a serious symptom with various aetiologies. Our aim was to define the aetiologies, outcomes and associations with lung cancer in the entire population of a high-income country.This retrospective multicentre study was based on the French nationwide hospital medical information database collected over 5 years (2008-2012). We analysed haemoptysis incidence, aetiologies, geographical and seasonal distribution and mortality. We studied recurrence, association with lung cancer and mortality in a 3-year follow-up analysis.Each year, ~15 000 adult patients (mean age 62 years, male/female ratio 2/1) were admitted for haemoptysis or had haemoptysis as a complication of their hospital stay, representing 0.2% of all hospitalised patients. Haemoptysis was cryptogenic in 50% of cases. The main aetiologies were respiratory infections (22%), lung cancer (17.4%), bronchiectasis (6.8%), pulmonary oedema (4.2%), anticoagulants (3.5%), tuberculosis (2.7%), pulmonary embolism (2.6%) and aspergillosis (1.1%). Among incident cases, the 3-year recurrence rate was 16.3%. Of the initial cryptogenic haemoptysis patients, 4% were diagnosed with lung cancer within 3 years. Mortality rates during the first stay and at 1 and 3 years were 9.2%, 21.6% and 27%, respectively.This is the first epidemiological study analysing haemoptysis and its outcomes in an entire population. Haemoptysis is a life-threatening symptom unveiling potentially life-threatening underlying conditions.

  15. Massive stars: flare activity due to infalls of comet-like bodies

    NASA Astrophysics Data System (ADS)

    Ibadov, Subhon; Ibodov, Firuz S.

    2015-01-01

    Passages of comet-like bodies through the atmosphere/chromosphere of massive stars at velocities more than 600 km/s will be accompanied, due to aerodynamic effects as crushing and flattening, by impulse generation of hot plasma within a relatively very thin layer near the stellar surface/photosphere as well as ``blast'' shock wave, i.e., impact-generated photospheric stellar/solar flares. Observational manifestations of such high-temperature phenomena will be eruption of the explosive layer's hot plasma, on materials of the star and ``exploding'' comet nuclei, into the circumstellar environment and variable anomalies in chemical abundances of metal atoms/ions like Fe, Si etc. Interferometric and spectroscopic observations/monitoring of young massive stars with dense protoplanetary discs are of interest for massive stars physics/evolution, including identification of mechanisms for massive stars variability.

  16. 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

  17. Interventional Management of Massive Hemothorax Due to Inadvertent Puncture of an Aberrant Right Subclavian Artery

    SciTech Connect

    Jahnke, Thomas Schaefer, Phillip Jost; Heller, Martin; Mueller-Huelsbeck, Stefan

    2008-07-15

    We report a case of massive hemothorax due to inadvertent puncture of an aberrant right subclavian artery during central venous access. Iatrogenic laceration at the origin of the right internal thoracic artery was successfully treated with coil embolization of the internal thoracic artery followed by stent-graft placement into the subclavian artery. Due to its elongated and abnormal course, an aberrant right subclavian artery may predispose to inadvertent puncture during vein catheterization and should be recognized as a potential threat for such procedures. Our case emphasizes that ultrasound guidance should be used routinely for central venous lines wherever possible.

  18. Massive Alimentary Tract Bleeding due to Cytomegalovirus Infection in an Elderly Patient.

    PubMed

    Koc, Bora; Bircan, Huseyin Yuce; Altaner, Semsi; Cinar, Ozlem; Ozcelik, Umit; Yavuz, Alpaslan; Kemik, Ozgur

    2014-08-13

    In recent years, cytomegalovirus (CMV) has been recognized as an important common pathogen in immunocompromized patients. This is due to the increasing number of immunosuppressive medications, intensive cancer chemotherapy use, recurrent transplantations, progressively aging population, and the higher number of human immunodeficiency virus infections. Cytomegalovirus infection especially interests the gastrointestinal tract, anywhere, from the mouth to the anus. Namely, the most commonly affected area is the colon, followed by duodenum, stomach, esophagus and small intestine. The most frequent manifestations of CMV colitis are: diarrhea, fever, gastrointestinal bleeding and abdominal pain. We report here the case of an 82-year-old woman, who was treated for non-Hodgkin lymphoma; she was admitted to the emergency department for abdominal pain and diffuse arthralgia, following massive upper- and lower- gastrointestinal bleeding, due to duodenal and colonic ulcers related to CMV infection. PMID:25276331

  19. Tracheal Lobular Capillary Haemangioma: A Rare Benign Cause of Recurrent Haemoptysis

    PubMed Central

    Kotidis, Konstantinos; Loubani, Mahmoud

    2016-01-01

    Lobular capillary haemangioma (LCH), previously known as pyogenic granuloma, is a benign vascular lesion commonly found within the oral and nasal cavity. However, it is rarely encountered within the trachea, where presenting features include recurrent haemoptysis, cough, and wheeze. We here describe a case of a 7 mm tracheal LCH in a 56-year-old woman, which was successfully resected at interventional bronchoscopy using biopsy forceps. Clinicians should be aware of tracheal LCH in the differential diagnosis for recurrent haemoptysis. PMID:27747126

  20. [Massive increase of foetal abdominal circumference due to hereditary polycystic kidney disease].

    PubMed

    Dukic, L; Schaffelder, R; Schaible, T; Sütterlin, M; Siemer, J

    2010-06-01

    Autosomal recessive polycystic kidney disease (ARPKD) is a rare condition with a poor prognosis. We report on a 30-year-old primagravid woman in the 34th) week of gestation who was admitted to our hospital. ARPKD of the foetus had been sonographically suspected since the 26th week of gestation. Ultrasound examination showed big polycystic kidneys on both sides. The non-consanguineous parents wanted a maximum therapy for the infant. Foetal digitalisation because of heart insufficiency and prophylactic lung maturation was started. In the further course, Doppler sonographic values worsened and a Caesarean section was performed in the 34th week of gestation at the demand of the parents and due to the expected problems in case of a vaginal delivery. The weight of the newborn was 3,780 g and the abdominal circumference was 50 cm. The newborn was intubated immediately after birth and artificial ventilation was performed. Extracorporeal membrane oxygenation was not possible due to the bad cardial condition. The boy died 16 h after delivery. The parents refused genetic examination and autopsy of the newborn. ARPKD is a severe disease that may have obstetric relevance, due to the massively increased abdominal circumference. Therefore, termination of pregnancy or preterm induction of labor should be considered in order to avoid Caesarean section. Additionally, early prenatal diagnosis with genetic analysis of PRKD1 in cases of suspected ARPKD can be helpful. PMID:20574939

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

    PubMed Central

    Kim, Jong-Hyun; Jeong, So-Young

    2015-01-01

    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

  2. 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.

  3. 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

  4. 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

    2014-09-09

    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.

  5. Absence of the left pulmonary artery in a young man with haemoptysis.

    PubMed

    Schweisfurth, H; Jachmann, M; Schoettes, C; Lorenz, H

    1994-06-01

    We report the case of a white male aged 21 yrs, who was admitted for acute onset of haemoptysis. His past medical history was normal and he had not previously been hospitalized. He was very active in track and field sports and was trained in scuba-diving. Physical examination revealed a grade 2/6 holosystolic heart murmur. Laboratory parameters, blood gases and pulmonary function tests were within the normal range. Fibreoptic bronchoscopy revealed normal geometry of the bronchi, with blood clots in the left lower lobe. An X-ray of the chest showed that the heart was shifted to the left side. In the perfusion scan, defects of the tracer on the left lung were detected. By ergospirometry, no significantly pathological response to exercise using a bicycle ergometer could be observed. By means of pulmonary artery catheterization, cardioangiography and selective angiography of the aorta the absence of the left pulmonary artery could be established, without any further malformations of the cardiopulmonary system. Because of the spontaneous cessation of haemoptysis, no surgical intervention was necessary.

  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. 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.

  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. Massive Bleeding as the First Clinical Manifestation of Metastatic Prostate Cancer due to Disseminated Intravascular Coagulation with Enhanced Fibrinolysis

    PubMed Central

    Lopes, João Madeira; Victorino, Rui M. M.; Meneses Santos, João

    2016-01-01

    Disseminated intravascular coagulation (DIC) is the most frequent coagulation disorder associated with metastatic prostate adenocarcinoma. However, DIC with enhanced fibrinolysis as an initial presentation of prostate cancer is extremely rare. The appropriate treatment to control bleeding in these situations is challenging, controversial, and based on isolated case reports in the literature. A 66-year-old male presented at the emergency department with acute severe spontaneous ecchymoses localized to the limbs, laterocervical hematoma, and hemothorax. Prostate specific antigen level was 385 μg/L, bone scintigraphy revealed multiple bone metastases, and prostate biopsy confirmed adenocarcinoma (Gleason 9; 4 + 5). Laboratory investigation showed a pattern of enhanced fibrinolysis rather than the more common intravascular coagulation mechanism. Epsilon aminocaproic acid in monotherapy was initiated with a clear and rapid control of bleeding manifestations. This rare case of massive bleeding due to DIC with enhanced fibrinolysis as the first manifestation of prostate cancer suggests that in selected cases where the acute bleeding dyscrasia is clearly associated with a dominant fibrinolysis mechanism it is possible to use an approach of monotherapy with antifibrinolytics. PMID:27803823

  10. Near-fatal persistent anion- and osmolal-gap acidosis due to massive gamma-butyrolactone/ethanol intoxication.

    PubMed

    Heytens, Luc; Neels, Hugo; Van Regenmortel, Niels; van den Brink, Wim; Henckes, Manu; Schouwers, Sofie; Dockx, Greet; Crunelle, Cleo L

    2015-03-01

    We report a case of an ethanol and massive gamma-butyrolactone (GBL) intoxication, the precursor of the recreational drug gamma-hydroxybutyric acid (GHB), resulting in life-threatening metabolic acidosis (pH 6.5) with a highly increased anion- and osmolal gap. Rapid analysis using gas chromatography revealed a GHB plasma concentration of 4400 mg/L, far above the upper limit concentration of 1000 mg/L found in adult fatalities attributed to GBL. Full recovery was established following supportive treatment including haemodialysis. This is the first report of a combined ethanol/GBL intoxication as a cause of high serum anion- and osmolal-gap metabolic acidosis.

  11. 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.

  12. 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.

  13. Unpredicted Sudden Death due to Recurrent Infratentorial Hemangiopericytoma Presenting as Massive Intratumoral Hemorrhage: A Case Report and Review of the Literature.

    PubMed

    Tanaka, Toshihide; Kato, Naoki; Hasegawa, Yuzuru; Murayama, Yuichi

    2014-01-01

    Unpredicted sudden death arising from hemangiopericytoma with massive intracranial hemorrhage is quite rare. We encountered a patient with recurrent infratentorial hemangiopericytoma presenting as life-threatening massive intracerebral hemorrhage. A 43-year-old man who had undergone craniotomy for total resection of an infratentorial hemangiopericytoma 17 months earlier presented with morning headache and generalized convulsions. Computed tomography revealed a massive hematoma in the right infratentorial region causing tonsillar herniation and emergency surgery was performed to evacuate the hematoma. Histological findings revealed hemangiopericytoma with hemorrhage. Neurological status remained unimproved and brain death was confirmed postoperatively. Hemangiopericytoma presenting as massive hemorrhage is quite rare. Since the risk of life-threatening massive hemorrhage should be considered, careful postoperative long-term follow-up is very important to identify tumor recurrences, particularly in the posterior cranial fossa, even if the tumor is completely removed.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. Massive gravity

    NASA Astrophysics Data System (ADS)

    Mukohyama, Shinji

    2013-09-01

    The concept of mass has been central in many areas of physics. Gravitation is not an exception, and it has been one of the long-standing questions whether the graviton, a spin-2 particle that mediates gravity, can have a non-vanishing mass or not. This question is relevant from not only theoretical but also phenomenological viewpoints, since a nonzero graviton mass may lead to late-time acceleration of the universe and thus may be considered as an alternative to dark energy. In 2010, de Rham, Gabadadze and Tolley proposed the first example of a fully nonlinear massive gravity theory and showed that the so called Boulware-Deser ghost, which had been one of the major obstacles against a stable nonlinear theory of massive gravity since 1972, can be removed by construction. Since then, nonlinear massive gravity has been attracting significant interest among physicists and cosmologists. The nonlinear theory of massive gravity provides a theoretical framework in which properties of the remaining five physical degrees of freedom of massive gravity can be studied. As always with any low-energy effective theories, one of the first tasks would be to identify good and bad backgrounds. Depending on the choice of backgrounds, some of the five degrees of freedom may become strongly coupled, may exhibit instantaneous propagation, or may lead to ghost/gradient instabilities. A related subject is to seek interesting solutions such as those relevant for astrophysical objects and those describing self-accelerating cosmology. Those solutions will allow us to study phenomenological and cosmological implications of the theory. Yet another important task would be to seek a possible (partial) UV completion that can be applied beyond the regime of validity of the low-energy effective theory that we currently know of. We invited articles to cover those important subjects in massive gravity. Given the recent rapid developments in the field, however, it must be noted that this focus issue

  20. 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

  1. Volcanogenic Massive Sulfide Deposit Density

    USGS Publications Warehouse

    Mosier, Dan L.; Singer, Donald A.; Berger, Vladimir I.

    2007-01-01

    A mineral-deposit density model for volcanogenic massive sulfide deposits was constructed from 38 well-explored control areas from around the world. Control areas contain at least one exposed volcanogenic massive sulfide deposit. The control areas used in this study contain 150 kuroko, 14 Urals, and 25 Cyprus massive sulfide subtypes of volcanogenic massive sulfide deposits. For each control area, extent of permissive rock, number of exposed volcanogenic massive sulfide deposits, map scale, deposit age, and deposit density were determined. The frequency distribution of deposit densities in these 38 control areas provides probabilistic estimates of the number of deposits for tracts that are permissive for volcanogenic massive sulfide deposits-90 percent of the control areas have densities of 100 or more deposits per 100,000 square kilometers, 50 percent of the control areas have densities of 700 or more deposits per 100,000 square kilometers, and 10 percent of the control areas have densities of 3,700 or more deposits per 100,000 square kilometers. Both map scale and the size of the control area are shown to be predictors of deposit density. Probabilistic estimates of the number of volcanogenic massive sulfide deposits can be made by conditioning the estimates on sizes of permissive area. The model constructed for this study provides a powerful tool for estimating the number of undiscovered volcanogenic massive sulfide deposits when conducting resource assessments. The value of these deposit densities is due to the consistency of these models with the grade and tonnage and the descriptive models. Mineral-deposit density models combined with grade and tonnage models allow reasonable estimates of the number, size, and grades of volcanogenic massive sulfide deposits to be made.

  2. 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

  3. Massive transfusion and massive transfusion protocol.

    PubMed

    Patil, Vijaya; Shetmahajan, Madhavi

    2014-09-01

    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.

  4. Megaloblastic anemia presenting with massive reversible splenomegaly.

    PubMed

    Behera, Vineet; Randive, Makarand; Sharma, Praveen; Nair, Velu

    2015-06-01

    Megaloblastic anemia (MA) is a common disorder with varied manifestations. It generally results in mild to moderate splenomegaly which is due to sequestration of macrocytic erythrocytes in spleen. Massive splenomegaly is generally seen in infections, myeloproliferative diseases, neoplasms, storage disorders or hematological conditions; but is not heard of and has rarely been reported in MA. We discuss a case of massive splenomegaly who presented with symptomatic anemia and was found to have MA. He was extensive evaluated for all other causes of massive splenomegaly which was normal. Further, after a therapeutic trial of MA he showed a regression in spleen size confirming that the massive splenomegaly was attributable to MA. PMID:25825577

  5. Constraining massive star evolution from massive clusters

    NASA Astrophysics Data System (ADS)

    Chene, Andre-Nicolas; Herve, Anthony; Martins, Fabrice; Bouret, Jean-Claude; Borissova, Jordanka; Ramirez, Sebastian; Kurtev, Radostin; Kumar, Nanda; Amigo, Pia; Fierro, Celia

    2013-06-01

    The exact evolution of massive stars is not accurately known at present. The general trend is that stars with masses above 40 - 60 Mo go from O-type stars to H-rich WN stars, and Luminous Blue Variables (?), before turning into H-poor WN stars and finally WC stars. At lower masses, the H-rich WN and LBV phases are replaced by a blue and a red supergiant phases, respectively. However, what are the details of such evolutionary sequences? The study of massive clusters is a golden opportunity to establish this. Indeed, the turn-off mass of massive clusters can be directly translated into the mass, and hence the nature, of the progenitors of their evolved objects contents. So far, only the Arches, Quintuplet, NGC3603, NGC2244 and central clusters have been studied this way. But 6 newly discovered heavily-obscured clusters in the large survey â"VISTA Variables in the Via Lactea" (VVV) have been found to have Wolf-Rayet stars as well as blue and/or red supergiants, together with many main sequence OB stars. This poster presents our efforts to model the massive star components of these clusters using CMFGEN, bringing new blocks to the pavement of massive stellar evolution and more than doubling the number of clusters in which such evolutionary sequence are established.

  6. 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.

  7. 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.

  8. Logistics of massive transfusions.

    PubMed

    DeLoughery, Thomas G

    2010-01-01

    Care of the patient with massive bleeding involves more than aggressive surgery and infusion of large amounts of blood products. The proper management of massive transfusions-whether they are in trauma patients or other bleeding patients-requires coordination of the personnel in the surgical suite or the emergency department, the blood bank, and laboratory.

  9. Morganella morganii sepsis with massive hemolysis.

    PubMed

    Kim, Jong Hoon; Cho, Chong Rae; Um, Tae Hyun; Rhu, Ji Yoon; Kim, Eu Suk; Jeong, Jae Won; Lee, Hye Ran

    2007-12-01

    Morganella morganii is a facultative gram-negative and anaerobic rod. It may be a cause of devastating infections in neonates and immunocompromised hosts. Some bacterial infections such as Clostridium and Vibrio are associated with hemolysis. However, massive hemolysis caused by M. morganii sepsis has not yet been reported. We observed a 59-yr-old man who had chemotherapy-induced neutropenia and was found to have massive hemolysis and metabolic acidosis due to sepsis. He died 6 hr after admission in spite of aggressive treatment. Two sets of blood cultures revealed the growth of M. morganii. We report here that M. morganii sepsis can cause fatal massive hemolysis leading to death.

  10. 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.

  11. Massive Supergravity and Deconstruction

    SciTech Connect

    Gregoire, Thomas; Schwartz, Matthew D.; Shadmi, Yael

    2004-03-23

    We present a simple superfield Lagrangian for massive supergravity. It comprises the minimal supergravity Lagrangian with interactions as well as mass terms for the metric superfield and the chiral compensator. This is the natural generalization of the Fierz-Pauli Lagrangian for massive gravity which comprises mass terms for the metric and its trace. We show that the on-shell bosonic and fermionic fields are degenerate and have the appropriate spins: 2, 3/2, 3/2 and 1. We then study this interacting Lagrangian using goldstone superfields. We find that achiral multiplet of goldstones gets a kinetic term through mixing, just as the scalar goldstone does in the non-supersymmetric case. This produces Planck scale (Mpl) interactions with matter and all the discontinuities and unitarity bounds associated with massive gravity. In particular, the scale of strong coupling is (Mpl m^4)^1/5, where m is the multiplet's mass. Next, we consider applications of massive supergravity to deconstruction. We estimate various quantum effects which generate non-local operators in theory space. As an example, we show that the single massive supergravity multiplet in a 2-site model can serve the function of an extra dimension in anomaly mediation.

  12. 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

  13. 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.

  14. Massive Magnetic Core

    NASA Technical Reports Server (NTRS)

    1964-01-01

    The massive magnetic core of the Space Radiation Effects Laboratory's Synchrocyclotron at NASA's Langley Research Center. The 3000 ton (6 million pound), 36' x 21'x 19.5' assembly of forged steel serves as the heart of the 600 million electron volt, high energy proton accelerator.

  15. 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…

  16. 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.

  17. Update on massive transfusion.

    PubMed

    Pham, H P; Shaz, B H

    2013-12-01

    Massive haemorrhage requires massive transfusion (MT) to maintain adequate circulation and haemostasis. For optimal management of massively bleeding patients, regardless of aetiology (trauma, obstetrical, surgical), effective preparation and communication between transfusion and other laboratory services and clinical teams are essential. A well-defined MT protocol is a valuable tool to delineate how blood products are ordered, prepared, and delivered; determine laboratory algorithms to use as transfusion guidelines; and outline duties and facilitate communication between involved personnel. In MT patients, it is crucial to practice damage control resuscitation and to administer blood products early in the resuscitation. Trauma patients are often admitted with early trauma-induced coagulopathy (ETIC), which is associated with mortality; the aetiology of ETIC is likely multifactorial. Current data support that trauma patients treated with higher ratios of plasma and platelet to red blood cell transfusions have improved outcomes, but further clinical investigation is needed. Additionally, tranexamic acid has been shown to decrease the mortality in trauma patients requiring MT. Greater use of cryoprecipitate or fibrinogen concentrate might be beneficial in MT patients from obstetrical causes. The risks and benefits for other therapies (prothrombin complex concentrate, recombinant activated factor VII, or whole blood) are not clearly defined in MT patients. Throughout the resuscitation, the patient should be closely monitored and both metabolic and coagulation abnormalities corrected. Further studies are needed to clarify the optimal ratios of blood products, treatment based on underlying clinical disorder, use of alternative therapies, and integration of laboratory testing results in the management of massively bleeding patients.

  18. 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.

  19. Severe Obstructive Sleep Apnea Due to Massive Cervical Lipohypertrophy.

    PubMed

    Ugurlu, Alper Mete; Ersozlu, Tolga; Basat, Salih Onur; Ceran, Fatih

    2015-09-01

    Obstructive sleep apnea is a difficult problem to deal with. Many studies on the pathogenesis of obstructive sleep apnea were performed in the past, and we present cervical lipohypertrophy causing severe obstructive sleep apnea in this article.

  20. Formation of Massive Stars in Massive Young Clusters

    NASA Astrophysics Data System (ADS)

    Zinnecker, H.

    2004-12-01

    There are two scenarios for the formation of massive stars: the ``accretion'' and the ``coalescence'' scenario. Here we discuss the conditions for coalescence (mergers) to occur in very dense young star clusters. We also ask whether the observed multiplicity of tight massive stars in young clusters is consistent with failed mergers and tidal capture. Finally, we propose some ideas for the origin of many massive stars in the heart of the 30 Doradus cluster and other extragalactic starburst clusters. We believe that all massive star formation is triggered and propose a 4-stage process of massive star birth in dense clusters.

  1. 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.

  2. Massive Transfusion in Children.

    PubMed

    Karam, Oliver; Tucci, Marisa

    2016-10-01

    Massive transfusions occur frequently in pediatric trauma patients, among some children undergoing surgery, or in children with critical illness. Over the last years, many authors have studied different aspects of massive transfusions, starting with an operative definition. Some information is available on transfusion strategies and adjunctive treatments. Areas that require additional investigation include: studies to assess which children benefit from transfusion protocols based on fixed ratios of blood components vs transfusion strategies based on biophysical parameters and laboratory tests; whether goal-directed therapies that are personalized to the recipient will improve outcomes; or which laboratory tests best define the risk of bleeding and what clinical indicators should prompt the start and stop of massive transfusion protocols. In addition, critical issues that require further study include transfusion support with whole blood vs reconstituted whole blood prepared from packed red blood cells, plasma, and platelets; and the generation of high quality evidence that would lead to treatments which decrease adverse consequences of transfusion and improve outcomes.

  3. Massive gravity acausality redux

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    Massive gravity (mGR) is a 5(=2s+1) degree of freedom, finite range extension of GR. However, amongst other problems, it is plagued by superluminal propagation, first uncovered via a second order shock analysis. First order mGR shock structures have also been studied, but the existence of superluminal propagation in that context was left open. We present here a concordance of these methods, by an explicit (first order) characteristic matrix computation, which confirms mGR's superluminal propagation as well as acausality.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  12. Massive soliton stars

    SciTech Connect

    Chiu, Hongyee )

    1990-05-01

    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. 27 refs.

  13. Massively parallel processor computer

    NASA Technical Reports Server (NTRS)

    Fung, L. W. (Inventor)

    1983-01-01

    An apparatus for processing multidimensional data with strong spatial characteristics, such as raw image data, characterized by a large number of parallel data streams in an ordered array is described. It comprises a large number (e.g., 16,384 in a 128 x 128 array) of parallel processing elements operating simultaneously and independently on single bit slices of a corresponding array of incoming data streams under control of a single set of instructions. Each of the processing elements comprises a bidirectional data bus in communication with a register for storing single bit slices together with a random access memory unit and associated circuitry, including a binary counter/shift register device, for performing logical and arithmetical computations on the bit slices, and an I/O unit for interfacing the bidirectional data bus with the data stream source. The massively parallel processor architecture enables very high speed processing of large amounts of ordered parallel data, including spatial translation by shifting or sliding of bits vertically or horizontally to neighboring processing elements.

  14. 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.

  15. 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.

  16. 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.

  17. Fragmentation in massive star formation.

    PubMed

    Beuther, Henrik; Schilke, Peter

    2004-02-20

    Studies of evolved massive stars indicate that they form in a clustered mode. During the earliest evolutionary stages, these regions are embedded within their natal cores. Here we present high-spatial-resolution interferometric dust continuum observations disentangling the cluster-like structure of a young massive star-forming region. The derived protocluster mass distribution is consistent with the stellar initial mass function. Thus, fragmentation of the initial massive cores may determine the initial mass function and the masses of the final stars. This implies that stars of all masses can form via accretion processes, and coalescence of intermediate-mass protostars appears not to be necessary.

  18. 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.

  19. [Albumin and artificial colloids for massive bleeding].

    PubMed

    Iijima, Takehiko

    2011-01-01

    Rapid and massive bleeding has to be counteracted by efficient volume restoration against rapid loss of intravascular volume. There are two phases of volume management for massive bleeding, uncontrolled phase and controlled phase. During initial uncontrolled phase, rapid infusion of crystalloid with RCC (red cell concentrate) is the first choice of volume management to prevent shock and profound decline of hemoglobin level. After shifting to the next controlled phase, artificial colloids and RCC become the next choice for efficient volume restoration. Although albumin has not been proven to improve prognosis in clinical studies, anti-inflammatory effect could be expected. Albumin infusion may be followed in this phase, and also albumin concentrate may be beneficial to reduce subsequent tissue edema due to massive infusion of crystalloid and artificial colloid. A new generation of hydroxyethyl starch is a promising blood substitute, designed with minimum side effect. Although renal damage especially in septic patient and coagulation disorder are theoretically suspected, beneficial effect as volume expansion overwhelms these stochastic side effects. Since the side effect depends on the dose and how much it remains in the body, a purposeful use during volume expansion phase should be recommended.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. Massive Black Hole Binary Evolution

    NASA Astrophysics Data System (ADS)

    Merritt, David; Milosavljević, Milos

    2005-11-01

    Coalescence of binary supermassive black holes (SBHs) would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers) are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, "diffusive" refilling of the binary's loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the "damage" inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.

  5. Positive signs in massive gravity

    DOE PAGES

    Cheung, Clifford; Remmen, Grant N.

    2016-04-01

    Here, 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. Furthermore, 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 islandmore » in the parameter space of ghost-free massive gravity. And 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.« less

  6. 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.

  7. 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.

  8. Broadbeam for Massive MIMO Systems

    NASA Astrophysics Data System (ADS)

    Qiao, Deli; Qian, Haifeng; Li, Geoffrey Ye

    2016-05-01

    Massive MIMO has been identified as one of the promising disruptive air interface techniques to address the huge capacity requirement demanded by 5G wireless communications. For practical deployment of such systems, the control message need to be broadcast to all users reliably in the cell using broadbeam. A broadbeam is expected to have the same radiated power in all directions to cover users in any place in a cell. In this paper, we will show that there is no perfect broadbeam. Therefore, we develop a method for generating broadbeam that can allow tiny fluctuations in radiated power. Overall, this can serve as an ingredient for practical deployment of the massive MIMO systems.

  9. 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

  10. 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.

  11. Massive large-bowel haemorrhage.

    PubMed Central

    Roberts, P.; Thomas, P. A.

    1981-01-01

    Operative intervention for massive colonic haemorrhage is fortunately rarely necessary, but planned, low-risk segmental resections can only be performed if the bleeding site is known. This information can most frequently be obtained by using a combination of sigmoidoscopy, barium enema examination, and selective mesenteric angiography. PMID:6972724

  12. 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.

  13. 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…

  14. FAST TRACK COMMUNICATION: Positive energy of topologically massive gravity

    NASA Astrophysics Data System (ADS)

    Deser, S.

    2009-10-01

    I review how 'classical SUGRA' embeddability establishes positive energy for D = 3 topologically massive gravity, with or without a cosmological term, by a procedure familiar from D = 4 Einstein gravity (GR). This method also provides explicit energy expressions. In contrast to GR, it is not manifestly positive here, due to this theory's peculiar two-term nature.

  15. [Body contouring procedures for massive weight loss patients and their complications].

    PubMed

    Long, Xiao; Wang, Xiao-jun

    2011-06-01

    An increasing number of patients require body contouring procedures after massive weight loss. Body contouring can bring better quality of life and increase their satisfaction towards weight loss procedures. However, due to the special body status after massive weight loss, the complications of body contouring can be high. This article briefly describes body contouring procedures and summarizes their indications and complications.

  16. Massive retinal gliosis: An unusual case with immunohistochemical study

    PubMed Central

    Deshmukh, Sanjay D; Ashturkar, Amrut V; Babanagare, Shridhar V; Gokhale, Suvarna K; Deshpande, Anand A

    2011-01-01

    Massive retinal gliosis (MRG) is a rare, benign intraocular condition that results from the proliferation of well-differentiated glial cells. Immunohistochemically, these cells show positivity for glial fibrillary acid protein (GFAP), neuron specific enolase (NSE), and S-100 protein. We encountered a case of a 45-year-old female with loss of vision in the left eye. She had a history of trauma to that eye two years ago. Enucleation was carried out, because malignancy was suspected due to retinal calcification. On the basis of light microscopy and immunohistochemistry (IHC) performed on the enucleated eye, it was diagnosed as massive retinal gliosis. PMID:21586853

  17. 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

  18. [Surgical decompression for massive cerebellar infarction].

    PubMed

    Ogasawara, K; Koshu, K; Nagamine, Y; Fujiwara, S; Mizoi, K; Yoshimoto, T

    1995-01-01

    The authors report 10 patients with progressive neurological deterioration due to massive cerebellar infarctions. Computerized tomography scans confirmed obstructive hydrocephalus and brain stem compression. All 10 patients (seven men, three women; mean age, 59 years) were treated by external ventricular drainage and decompressive suboccipital craniectomy. After discharge from the hospital, they were followed up (23-101 months) and their functional independence was evaluated by the Barthel Index. The condition of three patients with brain-stem infarction had deteriorated despite decompressive surgery. Two of these died during the acute stage and one because severely disabled. The remaining seven patients showed neurological improvement during the postoperative period. Four patients with preoperative Japan Coma Scale of 100 returned to their previous jobs within the follow-up period and three patients with preoperative Japan Coma Scale of 200 required some assistance in daily activities. It is suggested that decompressive surgery may be beneficial for massive cerebellar infarction. The postoperative prognosis depends mainly on the presence or absence of coexisting brain-stem infarction. It is possible that, without brain-stem infarction, patients who remained in a "dependent" state may have recovered better if they had been operated on earlier.

  19. 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.

  20. Sinus histiocytosis with massive lymphadenopathy.

    PubMed

    Foucar, E; Rosai, J; Dorfman, R F

    1978-12-01

    Sinus histiocytosis with massive lymphadenopathy (SHML) is a newly recognized, distinct, pseudolymphomatous benign entity with very characteristic microscopic features. Most patients are children or young adults with massive painless cervical adenopathy, although other node groups and extranodal sites often are involved. Sixteen patients with SHML involving the upper respiratory tract and/ or salivary gland are presented. Nine of the patients had ear, nose, and throat (ENT) manifestations at the time of presentation. In most cases the ENT involvement resulted in prominent clinical symptoms. Treatment included surgery, antibiotics, irradiation, chemotherapy, and steroids, frequently in combination, but no consistent pattern of response emerged from the study. These 16 patients were very similar clinically to patients with SHML who did not have ENT disease, indicating that extranodal involvement is not associated with more aggressive disease.

  1. Massive star clusters in galaxies.

    PubMed

    Harris, William E

    2010-02-28

    The ensemble of all star clusters in a galaxy constitutes its star cluster system. In this review, the focus of the discussion is on the ability of star clusters, particularly the systems of old massive globular clusters (GCs), to mark the early evolutionary history of galaxies. I review current themes and key findings in GC research, and highlight some of the outstanding questions that are emerging from recent work.

  2. 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.

  3. WHAT SETS THE INITIAL ROTATION RATES OF MASSIVE STARS?

    SciTech Connect

    Rosen, Anna L.; Krumholz, Mark R.; Ramirez-Ruiz, Enrico

    2012-04-01

    The physical mechanisms that set the initial rotation rates in massive stars are a crucial unknown in current star formation theory. Observations of young, massive stars provide evidence that they form in a similar fashion to their low-mass counterparts. The magnetic coupling between a star and its accretion disk may be sufficient to spin down low-mass pre-main-sequence (PMS) stars to well below breakup at the end stage of their formation when the accretion rate is low. However, we show that these magnetic torques are insufficient to spin down massive PMS stars due to their short formation times and high accretion rates. We develop a model for the angular momentum evolution of stars over a wide range in mass, considering both magnetic and gravitational torques. We find that magnetic torques are unable to spin down either low-mass or high-mass stars during the main accretion phase, and that massive stars cannot be spun down significantly by magnetic torques during the end stage of their formation either. Spin-down occurs only if massive stars' disk lifetimes are substantially longer or their magnetic fields are much stronger than current observations suggest.

  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. 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.

  6. Voids in massive neutrino cosmologies

    SciTech Connect

    Massara, Elena; Villaescusa-Navarro, Francisco; Viel, Matteo; Sutter, P.M. E-mail: villaescusa@oats.inaf.it E-mail: sutter@oats.inaf.it

    2015-11-01

    Cosmic voids are a promising environment to characterize neutrino-induced effects on the large-scale distribution of matter in the universe. We perform a comprehensive numerical study of the statistical properties of voids, identified both in the matter and galaxy distributions, in massive and massless neutrino cosmologies. The matter density field is obtained by running several independent N-body simulations with cold dark matter and neutrino particles, while the galaxy catalogs are modeled by populating the dark matter halos in simulations via a halo occupation distribution (HOD) model to reproduce the clustering properties observed by the Sloan Digital Sky Survey (SDSS) II Data Release 7. We focus on the impact of massive neutrinos on the following void statistical properties: number density, ellipticities, two-point statistics, density and velocity profiles. Considering the matter density field, we find that voids in massive neutrino cosmologies are less evolved than those in the corresponding massless neutrinos case: there is a larger number of small voids and a smaller number of large ones, their profiles are less evacuated, and they present a lower wall at the edge. Moreover, the degeneracy between σ{sub 8} and Ω{sub ν} is broken when looking at void properties. In terms of the galaxy density field, we find that differences among cosmologies are difficult to detect because of the small number of galaxy voids in the simulations. Differences are instead present when looking at the matter density and velocity profiles around these voids.

  7. 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.

  8. Massive General Relativity: Theory and Applications

    NASA Astrophysics Data System (ADS)

    Gabadadze, Gregory

    that: (I) The theory, in a certain approxi- mation, predicts the selfaccelerated expansion that is due entirely to modified gravity. (II) In the same approximation, an arbitrary vacuum energy can be screened in this theory! However, the resulting fluctuations are not compatible with the present-day Universe. The present proposal is dedicated to further research and developments on both of the above issues. In the direction (I): PI intends to work out the selfaccelerated solution away from the approximation used in the preliminary studies and compare its predictions to the data. PI also proposes to study further novel properties of spherically symmetric solutions for stars, as well as properties of black holes in this theory. In the direction (II): PI proposes to attribute the screening solution of the CCP to very early cosmology, where the difficulty mentioned above can be resolved. It remains a challenge to work on to match consistently the screening solution to subsequent standard cosmology, followed by the selfacceleration. Furthermore, PI proposes to study the Hamiltonian of massive GR in terms of new variables which may be more appropriate for this theory. The issue of the strong coupling scale and related to it quantum loop corrections, will also be investigated. The proposed work has a direct significance for the Goals, Science Objectives and Re- search Focus Areas (RFA's) of NASA in general and the Astrophysics Theory Program in particular (Strategic Goal II; Theme: Structure and Evolution of the Universe; RFA’s 1(b,c)). To search whether Einstein's gravity is modified, and whether the dark energy effects in the Universe could be due to massive gravity, are among the major fundamental science questions.

  9. Properties of Massive Stars in VVV Clusters

    NASA Astrophysics Data System (ADS)

    Hervé, A.; Martins, F.; Chené, A.-N.; Bouret, J.-C.; Borrissova, J.

    2015-12-01

    The evolution of massive stars is only partly understood. Observational constraints can be obtained from the study of massive stars located in young massive clusters. The ESO Public Survey VISTA Variables in the Via Lactea (VVV) discovered several new clusters hosting massive stars (Borrissova et al. [1]). We derive the stellar parameters of all targets as well as surface abundances for a subset of them. For the cluster with the largest number of objects, we establish firmly that the WN and WC stars were initially more massive than the O stars still present in the cluster.

  10. 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.

  11. A clinical update on massive ovarian oedema – a pseudotumour?

    PubMed Central

    Praveen, RS; Pallavi, VR; Rajashekar, K; Usha, A; Umadevi, K; Bafna, UD

    2013-01-01

    Objective: Benign massive ovarian oedema is a rare clinical entity arising from the ovaries, and it poses a significant clinical challenge as it can be easily mistaken for neoplasm. Due to the lack of pathognomonic clinical features or characteristic hallmarks on non-invasive diagnostic modalities and the dependence on the final histopathology, the efforts of the surgeon have been deviated from performing fertility-sparing surgery on young women. The lack of standardised guidelines due to the rarity of this condition calls for a review of the literature to enable the clinician to formulate treatment guidelines. Methods and Material: A Medline search on the PubMed database for literature published in English from 1969 to 2011 was done using the keywords ‘massive ovarian oedema, massive ovarian oedema case report or case series, and pseudotumour of ovary’. A total of 177 women who had undergone a variety of treatments were retrieved. We also report the management options we used for four women presenting to us between August 2000 and October 2011, as well as a review of the literature. Result: A total of 177 cases of massive ovarian oedema were identified. Out of these cases 151 (85.3%) were primary massive ovarian oedema; secondary massive ovarian oedema was identified in 26 (14.7%) cases. A salpingo-oophorectomy was done in 145 (81.9%) cases, 12 (6.8%) cases had an abdominal hysterectomy with bilateral salpingo-oophorectomy. A total of 76 (42.9%) cases intraoperatively were found to have ovarian torsions, and one patient with primary massive ovarian oedema had ascites. Conservative treatment was carried out in 20 (11.3%) patients; 14 of these had a wedge biopsy with frozen section and with or without ovarian suspension, one patient had diagnostic laparotomy, and five cases had only ultrasonographic or magnetic resonance imaging monitoring and symptomatic treatment. The four cases treated at the regional cancer institute from 2000 to 2011 revealed that the first

  12. 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".

  13. 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.

  14. Hidden ghost in massive gravity

    NASA Astrophysics Data System (ADS)

    Chamseddine, Ali H.; Mukhanov, Viatcheslav

    2013-03-01

    The Hessian's determinant for a version of massive gravity given by an infinite expansion of a square root function of the induced metric, vanishes. We show that it allows us to eliminate one of four scalar fields used to generate the graviton mass. This, however, gives rise to the appearance of extra terms in the action with the squared time derivative of the metric, thus signaling that a nonlinear ghost survives. We demonstrate this phenomenon considering a simple system with constraint, which is supposed to reduce the number of physical degrees of freedom, however, we explicitly show how the constraint forces the metric to propagate an extra tachyonic state.

  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. Evolution and Nucleosynthesis of Very Massive Stars

    NASA Astrophysics Data System (ADS)

    Hirschi, Raphael

    In this chapter, after a brief introduction and overview of stellar evolution, we discuss the evolution and nucleosynthesis of very massive stars (VMS: M > 100 M_{odot } ) in the context of recent stellar evolution model calculations. This chapter covers the following aspects: general properties, evolution of surface properties, late central evolution, and nucleosynthesis including their dependence on metallicity, mass loss and rotation. Since very massive stars have very large convective cores during the main-sequence phase, their evolution is not so much affected by rotational mixing, but more by mass loss through stellar winds. Their evolution is never far from a homogeneous evolution even without rotational mixing. All VMS at metallicities close to solar end their life as WC(-WO) type Wolf-Rayet stars. Due to very important mass loss through stellar winds, these stars may have luminosities during the advanced phases of their evolution similar to stars with initial masses between 60 and 120 M_{odot } . A distinctive feature which may be used to disentangle Wolf-Rayet stars originating from VMS from those originating from lower initial masses is the enhanced abundances of neon and magnesium at the surface of WC stars. At solar metallicity, mass loss is so strong that even if a star is born with several hundred solar masses, it will end its life with less than 50 M_{odot } (using current mass loss prescriptions). At the metallicity of the LMC and lower, on the other hand, mass loss is weaker and might enable stars to undergo pair-instability supernovae.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Orbifold symmetry reductions of massive boson-fermion degeneracy

    NASA Astrophysics Data System (ADS)

    Florakis, Ioannis; Kounnas, Costas

    2009-10-01

    We investigate the existence of string vacua with Massive Spectrum Degeneracy Symmetry ( MSDS) in Heterotic and Type II orbifold constructions. We present a classification of all possible Z2N-orbifolds with MSDS symmetry that can be constructed in the formalism of the 2d free fermionic construction. We explicitly construct several two-dimensional models whose Reduced Massive Spectrum Degeneracy Symmetry ( RMSDS) is due to a set of Z-orbifold projections induced naturally in the framework of the free fermionic construction. In all proposed models the massive boson and fermion degrees of freedom exhibit Massive Spectrum Degeneracy Symmetry while the number of massless bosons n(b) and massless fermions n(f) are different; n(b)≠n(f). This property distinguishes the MSDSZ-twisted theories from ordinary supersymmetric ones. Some comments are stated concerning the large marginal JJ¯-deformations of the proposed models connecting them to higher-dimensional gauged-supergravity theories with non-trivial geometrical fluxes.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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

  7. LETTER TO THE EDITOR: Massive, topologically massive, models

    NASA Astrophysics Data System (ADS)

    Deser, S.; Tekin, Bayram

    2002-06-01

    In three dimensions, there are two distinct mass-generating mechanisms for gauge fields: adding the usual Proca/Pauli-Fierz, or the more esoteric Chern-Simons (CS), terms. Here, we analyse the three-term models where both types are present and their various limits. Surprisingly, in the tensor case, these seemingly innocuous systems are physically unacceptable. If the sign of the Einstein term is 'wrong', as is in fact required in the CS theory, then the excitation masses are always complex; with the usual sign, there is a (known) region of the two mass parameters where reality is restored, but instead a ghost problem arises, while for the 'pure mass' two-term system without an Einstein action, complex masses are unavoidable. This contrasts with the smooth behaviour of the corresponding vector models. Separately, we show that the 'partial masslessness' exhibited by (plain) massive spin-2 models in de Sitter backgrounds is shared by the three-term system: it also enjoys a reduced local gauge invariance when this mass parameter is tuned to the cosmological constant.

  8. 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.

  9. Massive splenic infarction and portal vein thrombosis in children with chronic myeloid leukemia.

    PubMed

    Aksu, Tekin; Erdem, Arzu Y; Fettah, Ali; Kaçar, Dilek; Avci, Zekai; Yarali, Nese; Tunc, Bahattin

    2014-10-01

    Massive splenic infarction and portal vein thrombosis (PVT) due to chronic myeloid leukemia (CML) is extremely rare. We describe 2 children who were presented with massive splenic infarction and PVT in the course of CML. Massive splenic infarction and PVT treated with splenectomy in one and with medical treatment in another in whom PVT resolved by cytoreductive treatment, led to downsizing of spleen or splenectomy. Splenic infarct and PVT should be considered in CML patients with long-lasting severe abdominal pain despite appropriate medical attempts. Splenectomy should be spared for persistent symptoms and complications.

  10. The Final Stages of Massive Star Evolution and Their Supernovae

    NASA Astrophysics Data System (ADS)

    Heger, Alexander

    In this chapter I discuss the final stages in the evolution of massive stars - stars that are massive enough to burn nuclear fuel all the way to iron group elements in their core. The core eventually collapses to form a neutron star or a black hole when electron captures and photo-disintegration reduce the pressure support to an extent that it no longer can hold up against gravity. The late burning stages of massive stars are a rich subject by themselves, and in them many of the heavy elements in the universe are first generated. The late evolution of massive stars strongly depends on their mass, and hence can be significantly effected by mass loss due to stellar winds and episodic mass loss events - a critical ingredient that we do not know as well as we would like. If the star loses all the hydrogen envelope, a Type I supernova results, if it does not, a Type II supernova is observed. Whether the star makes neutron star or a black hole, or a neutron star at first and a black hole later, and how fast they spin largely affects the energetics and asymmetry of the observed supernova explosion. Beyond photon-based astronomy, other than the sun, a supernova (SN 1987) has been the only object in the sky we ever observed in neutrinos, and supernovae may also be the first thing we will ever see in gravitational wave detectors like LIGO. I conclude this chapter reviewing the deaths of the most massive stars and of Population III stars.

  11. 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.

  12. Pancreaticopleural Fistula Causing Massive Right Hydrothorax and Respiratory Failure

    PubMed Central

    Chan, Esther Ern-Hwei

    2016-01-01

    Hydrothorax secondary to a pancreaticopleural fistula (PPF) is a rare complication of acute pancreatitis. In patients with a history of pancreatitis, diagnosis is made by detection of amylase in the pleural exudate. Imaging, particularly magnetic resonance cholangiopancreatography, aids in the detection of pancreatic ductal disruption. Management includes thoracocentesis and pancreatic duct drainage or pancreatic resection procedures. We present a case of massive right hydrothorax secondary to a PPF due to recurrent acute pancreatitis. Due to respiratory failure, urgent thoracocentesis was done. Distal pancreatectomy with splenectomy and cholecystectomy was performed. The patient remains well at one-year follow-up. PMID:27747128

  13. 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…

  14. A massively asynchronous, parallel brain.

    PubMed

    Zeki, Semir

    2015-05-19

    Whether the visual brain uses a parallel or a serial, hierarchical, strategy to process visual signals, the end result appears to be that different attributes of the visual scene are perceived asynchronously--with colour leading form (orientation) by 40 ms and direction of motion by about 80 ms. Whatever the neural root of this asynchrony, it creates a problem that has not been properly addressed, namely how visual attributes that are perceived asynchronously over brief time windows after stimulus onset are bound together in the longer term to give us a unified experience of the visual world, in which all attributes are apparently seen in perfect registration. In this review, I suggest that there is no central neural clock in the (visual) brain that synchronizes the activity of different processing systems. More likely, activity in each of the parallel processing-perceptual systems of the visual brain is reset independently, making of the brain a massively asynchronous organ, just like the new generation of more efficient computers promise to be. Given the asynchronous operations of the brain, it is likely that the results of activities in the different processing-perceptual systems are not bound by physiological interactions between cells in the specialized visual areas, but post-perceptually, outside the visual brain. PMID:25823871

  15. 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

  16. Massive pneumoperitoneum after scuba diving.

    PubMed

    Oh, Seung-Tak; Kim, Wook; Jeon, Hae-Myung; Kim, Jeong-Soo; Kim, Kee-Whan; Yoo, Seung-Jin; Kim, Eung-Kuk

    2003-04-01

    Pneumoperitoneum usually indicates rupture of a hollow viscus and considered a surgical emergency. But air may also enter the peritoneum from the lung or the genital organs in female without visceral perforation. While scuba diving, the rapid ascent is usually controlled by placing in a decompression chamber and the excess gas volume is exhaled. Failure to allow this excess gas to escape will result in overdistension of air passage, which may rupture resulting in pulmonary interstitial emphysema or, if air enters the circulation, air embolus can occur. Pneumo-peritoneum is a rare complication of diving accidents. While the majority of cases are not related to an intraabdominal catastrophy, more than 20% have been the result of gastric rupture. We report a 42-yr-old male patient with massive pneumoperitoneum after scuba diving, who presented himself with dyspnea and abdominal distension. Knowledge of this rare condition and its benign course may allow the emergency physician and surgeon to order appropriate studies to help avoid unnecessary surgical treatment. It is important to determine promptly whether the air emanated from a ruptured viscus or was introduced from an extraperitoneal source. Free air in the abdomen does not always indicate a ruptured intra-abdominal viscus.

  17. Massive Galaxies at z>4

    NASA Astrophysics Data System (ADS)

    Wiklind, Tommy G.; Mobasher, B.

    2008-03-01

    Combining observational data from optical to mid-infrared wavelengths, it has become possible to search for galaxies at look-back times of 12-13 Gyrs. The expectation is to find small and actively star forming systems. While these type of galaxies are indeed seen, a different type of galaxies are also found. These are characterized by having a stellar population which is old, relative to the age of the universe at that epoch, formation redshifts are in the range z=9-15, and to have a large stellar mass, in excess of (5-10) 10^10 Mo. In addition, these stellar systems are extra-odinarily compact, with half-ligth radii of just a few kpc. No counterpart to these objects can be identified in the local universe. In a recent study, we searched for such galaxies at redshifts zɱ in the GOODS South field, finding 11 candidates. Here we extend the search to include old and massive galaxies in the redshift range 4

  18. Mixing in massive stellar mergers

    NASA Astrophysics Data System (ADS)

    Gaburov, E.; Lombardi, J. C.; Portegies Zwart, S.

    2008-01-01

    The early evolution of dense star clusters is possibly dominated by close interactions between stars, and physical collisions between stars may occur quite frequently. Simulating a stellar collision event can be an intensive numerical task, as detailed calculations of this process require hydrodynamic simulations in three dimensions. We present a computationally inexpensive method in which we approximate the merger process, including shock heating, hydrodynamic mixing and mass loss, with a simple algorithm based on conservation laws and a basic qualitative understanding of the hydrodynamics of stellar mergers. The algorithm relies on Archimedes' principle to dictate the distribution of the fluid in the stable equilibrium situation. We calibrate and apply the method to mergers of massive stars, as these are expected to occur in young and dense star clusters. We find that without the effects of microscopic mixing, the temperature and chemical composition profiles in a collision product can become double-valued functions of enclosed mass. Such an unphysical situation is mended by simulating microscopic mixing as a post-collision effect. In this way we find that head-on collisions between stars of the same spectral type result in substantial mixing, while mergers between stars of different spectral type, such as type B and O stars (~10 and ~40Msolar respectively), are subject to relatively little hydrodynamic mixing. Our algorithm has been implemented in an easy-to-use software package, which we have made publicly available for download.1

  19. 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

  20. 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.

  1. 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

  2. Topologically massive gravity with extended supersymmetry

    NASA Astrophysics Data System (ADS)

    Lauf, Frederik; Sachs, Ivo

    2016-09-01

    We describe the construction of 2 +1 -dimensional toplogically massive anti-de Sitter gravity with N -extended supersymmetry in superspace by means of introducing a compensating hypermultiplet for the super-Weyl invariance. For N ≥3 , the scalar multiplet must be on shell and the potential for the scalar compensator is completely determined by the geometry. As a consequence, the resulting massive theory has no free parameter for N ≥4 . For N =4 , we show that this leads to topologically massive gravity at the chiral point and construct the corresponding off-shell component action.

  3. Accretion Disks in Massive Binary Systems

    NASA Astrophysics Data System (ADS)

    Djurašević, G. R.; Vince, I.; Atanacković, O.

    2010-12-01

    The results of our investigations of some massive close binaries (CB) (RY Sct, V448 Cyg, UU Cas and V455 Cyg), based on the photometric and spectroscopic observations indicate the existance of the accretion disk around the more massive component, located deep inside the Roche lobe. The light curve shapes of some of this systems are similar to the ones of the overcontact systems like W UMa, but the nature of these massive CBs is completely different. Here we present the models of these systems and their basic elements.

  4. 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

  5. Massive tongue necrosis secondary to temporal arteritis.

    PubMed

    Roseman, B B; Granite, E

    1984-10-01

    A case of unusually massive necrosis of the tongue secondary to temporal arteritis is presented. The clinician must include temporal arteritis in the differential diagnosis of patients presenting with signs and symptoms of tongue ischemia.

  6. Magnetic monopole solutions with a massive dilaton

    NASA Astrophysics Data System (ADS)

    Forgács, P.; Gyürüsi, J.

    1998-11-01

    Static, spherically symmetric monopole solutions of a spontaneously broken SU(2) gauge theory coupled to a massive dilaton field are studied in detail in function of the dilaton coupling strength and of the dilaton mass.

  7. 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

  8. 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.

  9. 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.

  10. Massive obstetric haemorrhage with disseminated intravascular coagulopathy.

    PubMed

    Su, Lin Lin; Chong, Yap Seng

    2012-02-01

    Massive obstetric haemorrhage is a major contributor towards maternal morbidity and mortality. The main causes are abruptio placentae, placenta praevia and postpartum haemorrhage. Clinicians managing pregnant women should be equipped with the knowledge and skills for managing massive obstetric haemorrhage to institute timely and appropriate life-saving treatment. Prompt resuscitation and reversal of coagulopathy are critical while definitive measures are carried out to arrest the bleeding. Massive antepartum haemorrhage necessitates deliveries whereas interventions for postpartum haemorrhage range from medical to surgical measures. Algorithms such as haemostasis are useful aids to the systematic and stepwise management of postpartum haemorrhage. Surgical measures used to avoid peripartum haemorrhage include uterine compression sutures, uterine balloon tamponade, uterine artery, and internal iliac artery ligation. Tranexamic acid and recombinant factor VII are more recent medical interventions in massive postpartum haemorrhage. Education, regular drills and adherence to guidelines and protocols are important to reduce haemorrhage-related maternal deaths. PMID:22101177

  11. 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.

  12. 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.

  13. 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.

  14. Massive-Star Magnetospheres: Now in 3-D!

    NASA Astrophysics Data System (ADS)

    Townsend, Richard

    Magnetic fields are unexpected in massive stars, due to the absence of a dynamo convection zone beneath their surface layers. Nevertheless, kilogauss-strength, ordered fields were detected in a small subset of these stars over three decades ago, and the intervening years have witnessed the steady expansion of this subset. A distinctive feature of magnetic massive stars is that they harbor magnetospheres --- circumstellar environments where the magnetic field interacts strongly with the star's radiation-driven wind, confining it and channelling it into energetic shocks. A wide range of observational signatures are associated with these magnetospheres, in diagnostics ranging from X-rays all the way through to radio emission. Moreover, these magnetospheres can play an important role in massive-star evolution, by amplifying angular momentum loss in the wind. Recent progress in understanding massive-star magnetospheres has largely been driven by magnetohydrodynamical (MHD) simulations. However, these have been restricted to two- dimensional axisymmetric configurations, with three-dimensional configurations possible only in certain special cases. These restrictions are limiting further progress; we therefore propose to develop completely general three-dimensional models for the magnetospheres of massive stars, on the one hand to understand their observational properties and exploit them as plasma-physics laboratories, and on the other to gain a comprehensive understanding of how they influence the evolution of their host star. For weak- and intermediate-field stars, the models will be based on 3-D MHD simulations using a modified version of the ZEUS-MP code. For strong-field stars, we will extend our existing Rigid Field Hydrodynamics (RFHD) code to handle completely arbitrary field topologies. To explore a putative 'photoionization-moderated mass loss' mechanism for massive-star magnetospheres, we will also further develop a photoionization code we have recently

  15. 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.

  16. 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.

  17. MULTIWAVELENGTH OBSERVATIONS OF MASSIVE STELLAR CLUSTER CANDIDATES IN THE GALAXY

    SciTech Connect

    Richards, Emily E.; Lang, Cornelia C.; Trombley, Christine; Figer, Donald F. E-mail: er7@indiana.edu

    2012-09-01

    The Galaxy appears to be richer in young, massive stellar clusters than previously known, due to advances in infrared surveys that have uncovered deeply embedded regions of star formation. Young, massive clusters can significantly impact the surrounding interstellar medium (ISM) and hence radio observations can also be an important tracer of their activity. Several hundred cluster candidates are now known by examining survey data. Here, we report on multiwavelength observations of six of these candidates in the Galaxy. We carried out 4.9 and 8.5 GHz Very Large Array observations of the radio emission associated with these clusters to obtain the physical characteristics of the surrounding gas, including the Lyman continuum photon flux and ionized gas mass. Spitzer Infrared Array Camera observations were also made of these regions, and provide details on the stellar population as well as the dust continuum and polycyclic aromatic hydrocarbon emission. When compared to the known young, massive clusters in the Galaxy, the six cluster candidates have less powerful Lyman ionizing fluxes and ionize less of the H II mass in the surrounding ISM. Therefore, these cluster candidates appear to be more consistent with intermediate-mass clusters (10{sup 3}-10{sup 4} M{sub Sun }).

  18. Cosmic Ray Generation by Massive Binary Black Hole in AGN

    NASA Astrophysics Data System (ADS)

    Dokuchaev, Vyacheslav I.

    A model of nonstationary giant bow shocks produced by a supersonic orbital motion of a gravitationally bound massive binary black hole in the dense and highly inhomegeneous environment of the central Broad line Region (BLR) of AGN is proposed. The environment necessary for shocks generation is provided by numerous short-living clouds of dense plasma which are continuously reproduced by destructive collissions of fast moving stars in a very compact central stellar cluster of AGN. Some part of the gravitational energy of supersonically orbiting massive binary black hole transforms into the shock wave and then into the broad -range electromagnetic radiation up to the high -energy gamma radiation and the energetic cosmic ray particles. The orbit of a binary is evolutionary contracting due to a frictional drag in a dense plasma until the gravitational radiation becomes more influential. The model provide also the suitable conditions for the acceleration of cosmic ray protons up to the ultra-high energies under the realistic parameters of a massive binary black hole and the BLR in AGN.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. Heavy element abundances and massive star formation

    NASA Technical Reports Server (NTRS)

    Wang, Boqi; Silk, Joseph

    1993-01-01

    The determination of the stellar initial mass function (IMF) remains a great challenge in astronomy. In the solar neighborhood, the IMF is reasonable well determined for stellar masses from about 0.1 to 60 solar mass. However, outside the solar neighborhood, the IMF is poorly known. Among those frequently discussed arguments favoring a different IMF outside the solar neighborhood are the estimated time to consume the remaining gas in spiral galaxies, and the high rate of forming massive stars in starburst galaxies. An interesting question then is whether there may be an independent way of testing possible variations in the IMF. Indeed, the heavy elements in the interstellar medium are mostly synthesized in massive stars, so increasing, or decreasing, the fraction of massive stars naturally leads to a variation in the heavy element yield, and thus, the metallicity. The observed abundance should severely constrain any deviations of the IMF from the locally determined IMF. We focus on element oxygen, which is the most abundant heavy element in the interstellar medium. Oxygen is ejected only by massive stars that can become Type 1 supernovae, and the oxygen abundance is, therefore, a sensitive function of the fraction of massive stars in the IMF. Adopting oxygen enables us to avoid uncertainties in Type 1 supernovae. We use the nucleosynthesis results to calculate the oxygen yield for given IMF. We then calculate the oxygen abundance in the interstellar medium assuming instantaneous recycling of oxygen.

  8. 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.

  9. Primordial inhomogeneities from massive defects during inflation

    NASA Astrophysics Data System (ADS)

    Firouzjahi, Hassan; Karami, Asieh; Rostami, Tahereh

    2016-10-01

    We consider the imprints of local massive defects, such as a black hole or a massive monopole, during inflation. The massive defect breaks the background homogeneity. We consider the limit that the physical Schwarzschild radius of the defect is much smaller than the inflationary Hubble radius so a perturbative analysis is allowed. The inhomogeneities induced in scalar and gravitational wave power spectrum are calculated. We obtain the amplitudes of dipole, quadrupole and octupole anisotropies in curvature perturbation power spectrum and identify the relative configuration of the defect to CMB sphere in which large observable dipole asymmetry can be generated. We observe a curious reflection symmetry in which the configuration where the defect is inside the CMB comoving sphere has the same inhomogeneous variance as its mirror configuration where the defect is outside the CMB sphere.

  10. Massive Particle Reflection from Moving Mirrors

    NASA Astrophysics Data System (ADS)

    Sfarti, Adrian

    2016-09-01

    We investigate the reflection of massive particles from moving mirrors. The adoption of the formalism based on the energy-momentum allowed us to derive the most general set of formulas, valid for massive and, in the limit, also for massless particles. We show that the momentum change of the reflecting particle always lies along the normal to the mirror, independent of the mirror speed. The subject is interesting not only to physicists designing concentrators for fascicles of massive particles and electron microscopes but also to computer scientists working in raytracing operating in the photon sector. The paper, far from being only theoretical, has profound and novel practical applications in both domains of engineering design and computer science.

  11. Eruptive outflow phases of massive stars

    NASA Astrophysics Data System (ADS)

    Smith, Nathan

    2011-07-01

    I review recent progress on understanding eruptions of unstable massive stars, with particular attention to the diversity of observed behavior in extragalatic optical transient sources that are generally associated with giant eruptions of luminous blue variables (LBVs). These eruptions are thought to represent key mass loss episodes in the lives of massive stars. I discuss the possibility of dormant LBVs and implications for the duration of the greater LBV phase and its role in stellar evolution. These eruptive variables show a wide range of peak luminosity, decay time, expansion speeds, and progenitor luminosity, and in some cases they have been observed to suffer multiple eruptions. This broadens our view of massive star eruptions compared to prototypical sources like Eta Carinae, and provides important clues for the nature of the outbursts. I will also review and discuss some implications about the possible physical mechanisms involved, although the cause of the eruptions is not yet understood.

  12. Massive Ovarian Oedema- A Case Report.

    PubMed

    Harke, Arun B; Sigamani, Karthik; Thukkaram, Chitra; Ramamurthy, Madhumittha; Sekar, Manjani

    2016-08-01

    Massive ovarian oedema is defined by WHO as formation of tumour like enlargement of one or both ovaries by oedema fluid. We report a case of a 18-year-old unmarried girl who presented with three months amenorrhoea and left sided lower abdominal pain with clinical and radiological diagnosis of cystic ovarian neoplasm. Patient underwent lapratomy with left salpingo-oophorectomy. A definitive diagnosis of Massive Ovarian Oedema (MOE) was offered on histopathological examination. The MOE should be differentiated from ovarian fibromatosis, ovarian fibroma, sclerosing stromal tumour and ovarian myxoma. The usual management of massive oedema of ovary is unilateral salpingo-oophorectomy, as the lesion is mistaken for primary ovarian neoplasm at laparotomy. Recognition of MOE is of great importance to prevent unnecessary oophorectomy in young patients and can be managed conservatively. We report this case of MOE for its rarity. PMID:27656451

  13. The holographic fermions dual to massive gravity

    NASA Astrophysics Data System (ADS)

    Fang, Li-Qing; Kuang, Xiao-Mei; Wu, Jian-Pin

    2016-10-01

    We investigate the properties of the spectral function of the fermionic operator in the field theory which is dual to a 4-dimensional massive gravity. We first study the Fermi surface and the dispersion relation in the dual boundary theory. We find that as the massive parameters is decreased, the Fermi momentum becomes lower and the low energy excitation near Fermi surface behaves more like non-Fermi liquid. Then, we introduce a dipole coupling in the bulk theory and explore the emergence of a gap in the fermionic spectral function. It is found that larger critical dipole coupling is needed to open the gap than that in Einstein gravity. Accordingly, in the field theory dual to massive gravity, it requires stronger negative dipole coupling to generate the marginal Fermi liquid.

  14. 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.

  15. 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.

  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. 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.

  18. 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.

  19. Physics of Mass Loss in Massive Stars

    NASA Astrophysics Data System (ADS)

    Puls, Joachim; Sundqvist, Jon O.; Markova, Nevena

    2015-01-01

    We review potential mass-loss mechanisms in the various evolutionary stages of massive stars, from the well-known line-driven winds of O-stars and BA-supergiants to the less-understood winds of Red Supergiants. We discuss optically thick winds from Wolf-Rayet stars and Very Massive Stars, and the hypothesis of porosity-moderated, continuum-driven mass loss from stars formally exceeding the Eddington limit, which might explain the giant outbursts from Luminous Blue Variables. We finish this review with a glance on the impact of rapid rotation, magnetic fields and small-scale inhomogeneities in line-driven winds.

  20. 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.

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

    DOE PAGES

    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

  2. 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

  3. 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.

  4. Kinematics of the inner thousand AU region around the young massive star AFGL 2591-VLA3: a massive disk candidate?

    NASA Astrophysics Data System (ADS)

    Wang, K.-S.; van der Tak, F. F. S.; Hogerheijde, M. R.

    2012-07-01

    Context. Recent detections of disks around young high-mass stars support the idea of massive star formation through accretion rather than coalescence, but the detailed kinematics in the equatorial region of the disk candidates is not well known, which limits our understanding of the accretion process. Aims: This paper explores the kinematics of the gas around a young massive star with millimeter-wave interferometry to improve our understanding of the formation of massive stars though accretion. Methods: We use Plateau de Bure interferometric images to probe the environment of the nearby (~1 kpc) and luminous (~20 000 L⊙) high-mass (10-16 M⊙) young star AFGL 2591-VLA3 in continuum and in lines of HDO, H_218O and SO2 in the 115 and 230 GHz bands. Radiative transfer calculations are employed to investigate the kinematics of the source. Results: At ~0.5″ (500 AU) resolution, the line images clearly resolve the velocity field of the central compact source (diameter of ~800 AU) and show linear velocity gradients in the northeast-southwest direction. Judging from the disk-outflow geometry, the observed velocity gradient results from rotation and radial expansion in the equatorial region of VLA3. Radiative transfer calculations suggest that the velocity field is consistent with sub-Keplerian rotation plus Hubble-law like expansion. The line profiles of the observed molecules suggest a layered structure, with HDO emission arising from the disk mid-plane, H_218O from the warm mid-layer, and SO2 from the upper disk. Conclusions: We propose AFGL 2591-VLA3 as a new massive disk candidate, with peculiar kinematics. The rotation of this disk is sub-Keplerian, probably due to magnetic braking, while the stellar wind may be responsible for the expansion of the disk. The expansion motion may also be an indirect evidence of disk accretion in the very inner region because of the conservation of angular momentum. The sub-Keplerian rotation discovered in our work suggests that

  5. Complete recovery after massive ethylene glycol ingestion.

    PubMed

    Curtin, L; Kraner, J; Wine, H; Savitt, D; Abuelo, J G

    1992-06-01

    We treated a 64-year-old man who recovered completely from a massive antifreeze ingestion with ethylene glycol levels well above those of previously described survivors. Rapid and aggressive treatment of the patient with recognized methods, including hemodialysis, resulted in the favorable outcome.

  6. 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.

  7. 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.

  8. 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…

  9. 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…

  10. 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…

  11. Some correlations for massive MS stars.

    NASA Astrophysics Data System (ADS)

    Angelov, T.

    1994-11-01

    Criteria are derived for estimating the values of photospheric density, of the core mass and of the energy-generation rate for massive main-sequence stars. Based on the observational material concerning M, L and Te the demarcation lines are determined for the domain of values expected for these quantities in cor relation with measured Mb.

  12. 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⊙.

  13. 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.

  14. State of the art: massive transfusion.

    PubMed

    McDaniel, L M; Etchill, E W; Raval, J S; Neal, M D

    2014-06-01

    The aim of this article was to review recent developments in the resuscitation of both trauma and non-trauma patients in haemorrhagic shock. Strategies for the resuscitation of massively haemorrhaging patients and the use of massive transfusion protocols (MTPs) have been a major focus of the trauma literature over the past several years. The application of haemostatic resuscitation practices and MTPs to non-trauma populations has long been in practice, but has only recently been the subject of active research. Medline and PubMed were reviewed for 'massive transfusion' (MT) from 2012 to present. Non-English and paediatric articles were excluded. Articles were systematically reviewed for their relevance to MT. There were eight major areas of development identified. In recent MT literature, there was an increased focus on massively haemorrhaging non-trauma patients, the role of acute traumatic coagulopathy, the use of thromboelastography (TEG), and the impact of MTPs on blood product waste and efficiency of product delivery. Other developments included additional MT prediction tools and The PRospective Observational Multicenter Major Trauma Transfusion (PROMMTT) study. There was also interest in re-evaluating the clinical relevance of the current MT definition and identifying new foci for MT. These recent developments reflect efforts to better understand and manage non-traumatic haemorrhage and to address prior limitations in the trauma literature. Inevitably, new questions have been raised, which will likely direct ongoing and future research in MT.

  15. 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

  16. Topical perspective on massive threading and parallelism.

    PubMed

    Farber, Robert M

    2011-09-01

    Unquestionably computer architectures have undergone a recent and noteworthy paradigm shift that now delivers multi- and many-core systems with tens to many thousands of concurrent hardware processing elements per workstation or supercomputer node. GPGPU (General Purpose Graphics Processor Unit) technology in particular has attracted significant attention as new software development capabilities, namely CUDA (Compute Unified Device Architecture) and OpenCL™, have made it possible for students as well as small and large research organizations to achieve excellent speedup for many applications over more conventional computing architectures. The current scientific literature reflects this shift with numerous examples of GPGPU applications that have achieved one, two, and in some special cases, three-orders of magnitude increased computational performance through the use of massive threading to exploit parallelism. Multi-core architectures are also evolving quickly to exploit both massive-threading and massive-parallelism such as the 1.3 million threads Blue Waters supercomputer. The challenge confronting scientists in planning future experimental and theoretical research efforts--be they individual efforts with one computer or collaborative efforts proposing to use the largest supercomputers in the world is how to capitalize on these new massively threaded computational architectures--especially as not all computational problems will scale to massive parallelism. In particular, the costs associated with restructuring software (and potentially redesigning algorithms) to exploit the parallelism of these multi- and many-threaded machines must be considered along with application scalability and lifespan. This perspective is an overview of the current state of threading and parallelize with some insight into the future. PMID:21764615

  17. 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.

  18. Peering to the Heart of Massive Star Birth - V. Highest Priority Massive Protostars

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan

    2015-10-01

    As part of an on-going, multi-year program to build up a sample of massive and intermediate-mass protostars that are observed across MIR and FIR bands to test theoretical models of massive star formation, we propose to observe about 15 highest priority massive protostar targets with SOFIA-FORCAST with this Regular Program proposal. Especially the unique 37 micron imaging can help reveal thermal emission from outflow cavities and the relative fluxes from the near and far-facing sides probes the amount of dense gas in the immediate vicinity of the protostar. Core Accretion models generally involve larger quantities of such gas than Competitive Accretion models. We will compare observational results against specific predictions of a grid of radiative transfer simulations developed for the Turbulent Core Model of massive star formation.

  19. A massive chondroblastoma in the proximal humerus simulating malignant bone tumors.

    PubMed

    Tonogai, Ichiro; Takahashi, Mitsuhiko; Manabe, Hiroaki; Nishisho, Toshihiko; Iwamoto, Seiji; Takao, Shoichiro; Kagawa, Seiko; Kudo, Eiji; Yasui, Natsuo

    2013-01-01

    Chondroblastoma is a mostly benign bone neoplasm that typically affects the second decade of life and exhibits a lytic lesion in the epiphysis of long bones. We report an extreme case of massive, destructive chondroblastoma of the proximal humerus in a 9-year-old girl. It was difficult to differentiate using imaging information the lesion from malignant bone tumors such as osteosarcoma. Histopathological examination from biopsy proved chondroblastoma. The tumor was resected after preoperative transcatheter embolization. Reconstructive procedure for the proximal humerus was not performed due to the local destruction. The present case demonstrates clinical and radiological differentiations of the massive chondroblastoma from the other lesions and histopathological understandings for this lesion.

  20. 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.

  1. [Implementation of a massive transfusion protocol in an emergency department].

    PubMed

    Tonglet, M; Minon, J M; Damas, F; Clanet, M; Vergnion, M

    2014-02-01

    We present here the massive transfusion protocol implemented in our institution in 2013. It will improve our management of critical massive bleeding, a situation which is rare in in our hospital, but carries a high mortality risk.

  2. 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.

  3. Cosmological viability of massive gravity with generalized matter coupling

    NASA Astrophysics Data System (ADS)

    Solomon, Adam R.; Enander, Jonas; Akrami, Yashar; Koivisto, Tomi S.; Könnig, Frank; Mörtsell, Edvard

    2015-04-01

    There is a no-go theorem forbidding flat and closed FLRW solutions in massive gravity on a flat reference metric, while open solutions are unstable. Recently it was shown that this no-go theorem can be overcome if at least some matter couples to a hybrid metric composed of both the dynamical and the fixed reference metric. We show that this is not compatible with the standard description of cosmological sources in terms of effective perfect fluids, and the predictions of the theory become sensitive either to the detailed field-theoretical modelling of the matter content or to the presence of additional dark degrees of freedom. This is a serious practical complication. Furthermore, we demonstrate that viable cosmological background evolution with a perfect fluid appears to require the presence of fields with highly contrived properties. This could be improved if the equivalence principle is broken by coupling only some of the fields to the composite metric, but viable self-accelerating solutions due only to the massive graviton are difficult to obtain.

  4. The spectroscopic Hertzsprung-Russell diagram of Galactic massive stars

    NASA Astrophysics Data System (ADS)

    Castro, N.; Fossati, L.; Langer, N.; Simón-Díaz, S.; Schneider, F. R. N.; Izzard, R. G.

    2014-10-01

    The distribution of stars in the Hertzsprung-Russell diagram narrates their evolutionary history and directly assesses their properties. Placing stars in this diagram however requires the knowledge of their distances and interstellar extinctions, which are often poorly known for Galactic stars. The spectroscopic Hertzsprung-Russell diagram (sHRD) tells similar evolutionary tales, but is independent of distance and extinction measurements. Based on spectroscopically derived effective temperatures and gravities of almost 600 stars, we derive for the first time the observational distribution of Galactic massive stars in the sHRD. While biases and statistical limitations in the data prevent detailed quantitative conclusions at this time, we see several clear qualitative trends. By comparing the observational sHRD with different state-of-the-art stellar evolutionary predictions, we conclude that convective core overshooting may be mass-dependent and, at high mass (≳15 M⊙), stronger than previously thought. Furthermore, we find evidence for an empirical upper limit in the sHRD for stars with Teff between 10 000 and 32 000 K and, a strikingly large number of objects below this line. This over-density may be due to inflation expanding envelopes in massive main-sequence stars near the Eddington limit. Appendix A is available in electronic form at http://www.aanda.org

  5. 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.

  6. 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

  7. Understanding Ultra Massive Galaxies at Z~1.6

    NASA Astrophysics Data System (ADS)

    Arcila-Osejo, Liz; Sawicki, Marcin; Arnouts, Stephane; Moutard, Thibaud; Golob, Anneya

    2015-08-01

    Using an adaptation of the BzKs technique, we select and distinguish between star-forming and passive galaxies at high redshift in order to focus our attention on the most massive (Mstar > 1011 Msun), passive galaxies at high redshift (z~1.5-2). We will refer to these objects as Ultra-Massive Passive Galaxies or UMPEGs.It is of great interest trying to understand how massive passive galaxies can exist in large numbers by z~2, when the age of the Universe is just ~3 Gyr. Since they are already quenched by the time we observe them at the peak epoch of cosmic star formation, they must have attained very high rates of star formation to assemble their stellar masses in the short time available to them. Their SFRs at the time of quenching must have been several hundred Msun/yr. UMPEGs are also believed to reside in high-density environments, and due to their extremely large stellar masses are guaranteed to be the central galaxies of their host dark matter haloes.We use the CFHTLS Wide Fields and matching Ks-band observations (Arnouts et al. (in prep.)) covering an effective area of ~20 deg2 to select and study a large sample of UMPEGs at z~1.5--2. This large area provides us with a unique opportunity to detect these very rare and bright objects in large numbers and to effectively constrain the bright end of their luminosity and mass functions. Given how steep the stellar mass function is at its massive end (where we expect UMPEGS with stellar masses of Mstar > 1011 Msun), it is important to constrain it by building a representative sample. Thereby allowing us to understand their evolution from a very hight redshift of z=2 down to z=0 (for instance the contribution of dry mergers).We we will present a summary of properties of these rare but important objects based on our large sample of ~150 UMPEGS, including their luminosity and mass functions as well as general morphologies and SED-fitting results.

  8. 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

  9. Effects of massive star radiation on circumstellar disks evolution in the Eagle Nebula

    NASA Astrophysics Data System (ADS)

    Guarcello, Mario

    2007-09-01

    We will determine the frequency of disk and disk-less stars in the outer regions (relatively poor of massive stars) of the young cluster NGC 6611, with the aim to study the effects of UV flux due to massive stars on the evolution of circumstellar disks around low mass stars. Our previous results for the central region of the cluster show that this effect may be present, but we need to observe stars at larger distance from massive stars. This cluster is particularly well suited for our study, thanks to the irregular spatial distribution of its OB stars. CHANDRA observations are crucial for identifying the disk-less population undetectable with other method.

  10. Massive Nordström scalar (density) gravities from universal coupling

    NASA Astrophysics Data System (ADS)

    Pitts, J. Brian

    2011-03-01

    Both particle physics and the 1890s Seeliger-Neumann modification of Newtonian gravity suggest considering a “mass term” for gravity, yielding a finite range due to an exponentially decaying Yukawa potential. Unlike Nordström’s “massless” theory, massive scalar gravities are strictly Special Relativistic, being invariant under the Poincaré group but not the conformal group. Geometry is a poor guide to understanding massive scalar gravities: matter sees a conformally flat metric, but gravity also sees the rest of the flat metric, barely, in the mass term. Infinitely many theories exhibit this bimetric ‘geometry,’ all with the total stress-energy’s trace as source. All are new except the Freund-Nambu theory. The smooth massless limit indicates underdetermination of theories by data between massless and massive scalar gravities. The ease of accommodating electrons, protons and other fermions using density-weighted Ogievetsky-Polubarinov spinors in scalar gravity is noted.

  11. 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.

  12. Massive nonplanar two-loop maximal unitarity

    NASA Astrophysics Data System (ADS)

    Søgaard, Mads; Zhang, Yang

    2014-12-01

    We explore maximal unitarity for nonplanar two-loop integrals with up to four massive external legs. In this framework, the amplitude is reduced to a basis of master integrals whose coefficients are extracted from maximal cuts. The hepta-cut of the nonplanar double box defines a nodal algebraic curve associated with a multiply pinched genus-3 Riemann surface. All possible configurations of external masses are covered by two distinct topological pictures in which the curve decomposes into either six or eight Riemann spheres. The procedure relies on consistency equations based on vanishing of integrals of total derivatives and Levi-Civita contractions. Our analysis indicates that these constraints are governed by the global structure of the maximal cut. Lastly, we present an algorithm for computing generalized cuts of massive integrals with higher powers of propagators based on the Bezoutian matrix method.

  13. The initial conditions of massive star evolution

    NASA Astrophysics Data System (ADS)

    Sana, Hugues

    2016-07-01

    Massive stars are some of the most energetic building blocks of galaxies. They are the progenitors of supernovae and of neutrons stars and black holes, the coallescence of which is one of the most likely detectable sources of gravitational waves. Yet their formation remains poorly understood. As a consequence, the mechanisms that set initial parameters such as rotation rates, multiplicity and orbital distributions are also ill constrained. These quantities are however critical as they affect the internal mixing, the rate and nature of the interactions, the stars final fates and their end-of-life products. In this presentation, I will review existing and new observations that allow us to better constraints these parameters, hence the initial conditions for massive star evolution.

  14. How Massive Single Stars End Their Life

    NASA Technical Reports Server (NTRS)

    Heger, A.; Fryer, C. L.; Woosley, S. E.; Langer, N.; Hartmann, D. H.

    2003-01-01

    How massive stars die-what sort of explosion and remnant each produces-depends chiefly on the masses of their helium cores and hydrogen envelopes at death. For single stars, stellar winds are the only means of mass loss, and these are a function of the metallicity of the star. We discuss how metallicity, and a simplified prescription for its effect on mass loss, affects the evolution and final fate of massive stars. We map, as a function of mass and metallicity, where black holes and neutron stars are likely to form and where different types of supernovae are produced. Integrating over an initial mass function, we derive the relative populations as a function of metallicity. Provided that single stars rotate rapidly enough at death, we speculate on stellar populations that might produce gamma-ray bursts and jet-driven supernovae.

  15. Massive binaries in R136 using Hubble

    NASA Astrophysics Data System (ADS)

    Caballero-Nieves, Saida; Crowther, Paul; Bostroem, K. Azalee; Maíz Apellániz, Jesus

    2014-09-01

    We have undertaken a complete HST/STIS spectroscopic survey of R136, the young, central dense starburst cluster of the LMC 30 Doradus nebula, which hosts the most massive stars currently known. Our CCD datasets, comprising 17 adjacent 0.2"×52" long slits, were split across Cycles 19 and 20 to allow us to search for spectroscopic binaries. We will present the results of our survey, including a comparison with the massive-star population in the wider 30 Doradus region from the VLT Flames Tarantula survey. We will also describe upcoming HST/FGS observations, which will probe intermediate-separation binaries in R136, and discuss this cluster in the context of unresolved young extragalactic star clusters.

  16. Carcinoma of the cervix with massive eosinophilia.

    PubMed

    Lowe, D G

    1988-04-01

    Massive local eosinophilia of 100 or more eosinophils per high power field was found in 3.2% cases of invasive carcinoma of the cervix. The prevalence, length of history before presentation to surgery and histological features were similar in patients from Great Britain and Malawi, but in both populations the mean age at diagnosis was lower than in patients with cervical carcinomas without tissue eosinophilia. In some of the tumours, the malignant cells were very difficult to find because of the eosinophil infiltrate, and misinterpretation as an inflammatory lesion was possible. In the absence of circulating eosinophilia, cervical carcinomas with massive eosinophilia were found to have a better prognosis than tumours without. Five patients had circulating eosinophilia as well as local tumour eosinophil infiltration, and each of them had extensive tumour spread.

  17. Massive mesons in Weyl-Dirac theory

    NASA Astrophysics Data System (ADS)

    Mirabotalebi, S.; Ahmadi, F.; Salehi, H.

    2008-01-01

    In order to study the mass generation of the vector fields in the framework of a conformal invariant gravitational model, the Weyl-Dirac theory is considered. The mass of the Weyl’s meson fields plays a principal role in this theory, it connects basically the conformal and gauge symmetries. We estimate this mass by using the large-scale characteristics of the observed universe. To do this we firstly specify a preferred conformal frame as a cosmological frame, then in this frame, we introduce an exact possible solution of the theory. We also study the dynamical effect of the massive vector meson fields on the trajectories of an elementary particle. We show that a local change of the cosmological frame leads to a Hamilton-Jacobi equation describing a particle with an adjustable mass. The dynamical effect of the massive vector meson field presents itself in the form of a correction term for the mass of the particle.

  18. Cosmological perturbations in extended massive gravity

    NASA Astrophysics Data System (ADS)

    Gümrükçüoğlu, A. Emir; Hinterbichler, Kurt; Lin, Chunshan; Mukohyama, Shinji; Trodden, Mark

    2013-07-01

    We study cosmological perturbations around self-accelerating solutions to two extensions of nonlinear massive gravity: the quasi-dilaton theory and the mass-varying theory. We examine stability of the cosmological solutions, and the extent to which the vanishing of the kinetic terms for scalar and vector perturbations of self-accelerating solutions in massive gravity is generic when the theory is extended. We find that these kinetic terms are in general nonvanishing in both extensions, though there are constraints on the parameters and background evolution from demanding that they have the correct sign. In particular, the self-accelerating solutions of the quasi-dilaton theory are always unstable to scalar perturbations with wavelength shorter than the Hubble length.

  19. Very Massive Stars in the local Universe

    NASA Astrophysics Data System (ADS)

    Vink, Jorick S.; Heger, Alexander; Krumholz, Mark R.; Puls, Joachim; Banerjee, S.; Castro, N.; Chen, K.-J.; Chenè, A.-N.; Crowther, P. A.; Daminelli, A.; Gräfener, G.; Groh, J. H.; Hamann, W.-R.; Heap, S.; Herrero, A.; Kaper, L.; Najarro, F.; Oskinova, L. M.; Roman-Lopes, A.; Rosen, A.; Sander, A.; Shirazi, M.; Sugawara, Y.; Tramper, F.; Vanbeveren, D.; Voss, R.; Wofford, A.; Zhang, Y.

    2015-03-01

    Recent studies have claimed the existence of very massive stars (VMS) up to 300 M ⊙ in the local Universe. As this finding may represent a paradigm shift for the canonical stellar upper-mass limit of 150 M ⊙, it is timely to discuss the status of the data, as well as the far-reaching implications of such objects. We held a Joint Discussion at the General Assembly in Beijing to discuss (i) the determination of the current masses of the most massive stars, (ii) the formation of VMS, (iii) their mass loss, and (iv) their evolution and final fate. The prime aim was to reach broad consensus between observers and theorists on how to identify and quantify the dominant physical processes.

  20. Visser's massive graviton bimetric theory revisited

    SciTech Connect

    Roany, Alain de; Chauvineau, Bertrand; Freitas Pacheco, Jose A. de

    2011-10-15

    A massive gravity theory was proposed by Visser in the late 1990s. This theory, based on a background metric b{sub {alpha}{beta}} and on an usual dynamical metric g{sub {alpha}{beta}} has the advantage of being free of ghosts as well as discontinuities present in other massive theories proposed in the past. In the present investigation, the equations of Visser's theory are revisited with particular care on the related conservation laws. It will be shown that a multiplicative factor is missing in the graviton tensor originally derived by Visser, which has no incidence on the weak field approach but becomes important in the strong field regime when, for instance, cosmological applications are considered. In this case, contrary to some previous claims found in the literature, we conclude that a nonstatic background metric is required in order to obtain a solution able to mimic the {Lambda}CDM cosmology.

  1. Massive Smash-up at Vega

    NASA Technical Reports Server (NTRS)

    2005-01-01

    This artist concept illustrates how a massive collision of objects perhaps as large as the planet Pluto smashed together to create the dust ring around the nearby star Vega. New observations from NASA's Spitzer Space Telescope indicate the collision took place within the last one million years. Astronomers think that embryonic planets smashed together, shattered into pieces, and repeatedly crashed into other fragments to create ever finer debris.

    In the image, a collision is seen between massive objects that measured up to 2,000 kilometers (about 1,200 miles) in diameter. Scientists say the big collision initiated subsequent collisions that created dust particles around the star that were a few microns in size. Vega's intense light blew these fine particles to larger distances from the star, and also warmed them to emit heat radiation that can be detected by Spitzer's infrared detectors.

  2. The Stellar Halos of Massive Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Greene, Jenny E.; Murphy, Jeremy D.; Comerford, Julia M.; Gebhardt, Karl; Adams, Joshua J.

    2012-05-01

    We use the Mitchell Spectrograph (formerly VIRUS-P) on the McDonald Observatory 2.7 m Harlan J. Smith Telescope to search for the chemical signatures of massive elliptical galaxy assembly. The Mitchell Spectrograph is an integral-field spectrograph with a uniquely wide field of view (107'' × 107''), allowing us to achieve remarkably high signal-to-noise ratios of ~20-70 pixel-1 in radial bins of 2-2.5 times the effective radii of the eight galaxies in our sample. Focusing on a sample of massive elliptical galaxies with stellar velocity dispersions σ* > 150 km s-1, we study the radial dependence in the equivalent widths (EW) of key metal absorption lines. By twice the effective radius, the Mgb EWs have dropped by ~50%, and only a weak correlation between σ* and Mgb EW remains. The Mgb EWs at large radii are comparable to those seen in the centers of elliptical galaxies that are ~ an order of magnitude less massive. We find that the well-known metallicity gradients often observed within an effective radius continue smoothly to 2.5 Re , while the abundance ratio gradients remain flat. Much like the halo of the Milky Way, the stellar halos of our galaxies have low metallicities and high α-abundance ratios, as expected for very old stars formed in small stellar systems. Our observations support a picture in which the outer parts of massive elliptical galaxies are built by the accretion of much smaller systems whose star formation history was truncated at early times.

  3. Massive Multi-Agent Systems Control

    NASA Technical Reports Server (NTRS)

    Campagne, Jean-Charles; Gardon, Alain; Collomb, Etienne; Nishida, Toyoaki

    2004-01-01

    In order to build massive multi-agent systems, considered as complex and dynamic systems, one needs a method to analyze and control the system. We suggest an approach using morphology to represent and control the state of large organizations composed of a great number of light software agents. Morphology is understood as representing the state of the multi-agent system as shapes in an abstract geometrical space, this notion is close to the notion of phase space in physics.

  4. Have massive cosmological neutrinos already been detected

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1980-01-01

    The possibility is investigated that the decay of massive cosmological neutrinos may have produced a spectral signature which has already been detected in observations of the ultraviolet background radiation. Various implications are discussed including a possible implied neutrino mass of 13.8-14.8 eV. A lower limit is also placed on the lifetime of heavy neutrinos with respect to decay into light neutrinos and gamma rays based on the cosmic UV observations.

  5. Antenna Splitting Functions for Massive Particles

    SciTech Connect

    Larkoski, Andrew J.; Peskin, Michael E.; /SLAC

    2011-06-22

    An antenna shower is a parton shower in which the basic move is a color-coherent 2 {yields} 3 parton splitting process. In this paper, we give compact forms for the spin-dependent antenna splitting functions involving massive partons of spin 0 and spin 1/2. We hope that this formalism we have presented will be useful in describing the QCD dynamics of the top quark and other heavy particles at LHC.

  6. Comments on the Evolution of Massive Stars

    NASA Astrophysics Data System (ADS)

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

    We describe in a brief form present results we have obtained from a careful and up to date study of the evolution of massive stars including their advanced evolutionary phases beyond the oxygen burning phase. We describe the effects of mass loss, treatment of convection in inhomogeneous stellar layers and the rate of the 12C(α,γ)16O reaction on the properties of stellar models in the interesting case of a 25 M⊙ star of solar-like initial metallicity.

  7. 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

  8. Biomimetic Models for An Ecological Approach to Massively-Deployed Sensor Networks

    NASA Technical Reports Server (NTRS)

    Jones, Kennie H.; Lodding, Kenneth N.; Olariu, Stephan; Wilson, Larry; Xin, Chunsheng

    2005-01-01

    Promises of ubiquitous control of the physical environment by massively-deployed wireless sensor networks open avenues for new applications that will redefine the way we live and work. Due to small size and low cost of sensor devices, visionaries promise systems enabled by deployment of massive numbers of sensors ubiquitous throughout our environment working in concert. Recent research has concentrated on developing techniques for performing relatively simple tasks with minimal energy expense, assuming some form of centralized control. Unfortunately, centralized control is not conducive to parallel activities and does not scale to massive size networks. Execution of simple tasks in sparse networks will not lead to the sophisticated applications predicted. We propose a new way of looking at massively-deployed sensor networks, motivated by lessons learned from the way biological ecosystems are organized. We demonstrate that in such a model, fully distributed data aggregation can be performed in a scalable fashion in massively deployed sensor networks, where motes operate on local information, making local decisions that are aggregated across the network to achieve globally-meaningful effects. We show that such architectures may be used to facilitate communication and synchronization in a fault-tolerant manner, while balancing workload and required energy expenditure throughout the network.

  9. Massive graph visualization : LDRD final report.

    SciTech Connect

    Wylie, Brian Neil; Moreland, Kenneth D.

    2007-10-01

    Graphs are a vital way of organizing data with complex correlations. A good visualization of a graph can fundamentally change human understanding of the data. Consequently, there is a rich body of work on graph visualization. Although there are many techniques that are effective on small to medium sized graphs (tens of thousands of nodes), there is a void in the research for visualizing massive graphs containing millions of nodes. Sandia is one of the few entities in the world that has the means and motivation to handle data on such a massive scale. For example, homeland security generates graphs from prolific media sources such as television, telephone, and the Internet. The purpose of this project is to provide the groundwork for visualizing such massive graphs. The research provides for two major feature gaps: a parallel, interactive visualization framework and scalable algorithms to make the framework usable to a practical application. Both the frameworks and algorithms are designed to run on distributed parallel computers, which are already available at Sandia. Some features are integrated into the ThreatView{trademark} application and future work will integrate further parallel algorithms.

  10. Hyper massive black holes in evolved galaxies

    NASA Astrophysics Data System (ADS)

    Romero-Cruz, Fernando J.

    2015-09-01

    From the SDSS DR7 we took a sample of 16733 galaxies which do not show all of the emission lines required to classify their activity according to the classical BPT diagram (Baldwin et al. 1981 PASP). Since they do not show these emission lines they are thought to be evolved enough so to host Hyper Massive Black holes. We compared their statistical properties with other galaxies from the SDSS DR7 which do show emission lines and confirmed that their M-sigma relationship correspond to HMBHs (Gutelkin et al. 2009 ApJ) and also that their SFH confirms evolution. We also analyzed them with a new Diagnostic Diagram in the IR (Coziol et al. 2015 AJ) and found that their position in the IR color space (W3W4 vs W2W3) correspond to AGN activity with current low SF, another confirmation of an evolved galaxy. The position of our final sample in the IR diagram is in the same region in which Holm 15A lies, this galaxy is considered to host the most massive BHs in the nearby universe (Lopez-Cruz et al. 2014 ApJL). The morphology of these galaxies (all of them are classified as elliptical) confirms that they are very evolved. We claim that the hyper massive BH lie in galaxies very evolved and with very low SF and without clear AGN activity in the BPT diagram.

  11. MASSIVE STAR FORMATION IN NGC 2074

    SciTech Connect

    Fleener, Christine E.; Chu, Y.-H.; Gruendl, Robert A.; Payne, James T.; Chen, C.-H. Rosie

    2010-01-15

    Spitzer observations of the Large Magellanic Cloud (LMC) have revealed a large population of young stellar objects (YSOs), but complementary high-resolution images in the optical or near-IR wavelengths are still needed to resolve the multiplicity and immediate environments of the YSOs. The Hubble Space Telescope imaged the star-forming region NGC 2074 in the LMC during its 100,000th orbit, providing an opportunity to more closely examine the YSOs and their environments in this region. We have studied the 10 YSO candidates identified from Spitzer observations, confirming their nature and determining their physical parameters by modeling their spectral energy distributions. The majority of the YSOs and central stars of ultracompact H II regions in NGC 2074 have masses consistent with spectral types of early B to late O. The co-existence of massive early-type O stars and the less massive YSOs indicates that their formation may have started at a similar time, a few 10{sup 5} yr ago. NGC 2074 provides an opportunity to study the evolution of massive stars at their infancy.

  12. Radio jet interactions with massive clouds

    NASA Astrophysics Data System (ADS)

    Wiita, Paul J.; Wang, Zhongxiang; Hooda, Jagbir S.

    2002-05-01

    Three-dimensional simulations of light hydrodynamic jets are computed using the Zeus-3D code. We employ parameters corresponding to moderate to high power radio jets emerging through a galactic atmosphere or halo, and eventually crossing a tilted pressure matched interface with a hotter intracluster medium. These simulations aim the jets so that they hit massive dense clouds within the galactic halo. Such clouds are set up with radii several times that of the jet, and nominally correspond to giant molecular cloud complexes or small cannibalized galaxies. We find that powerful jets eventually disperse the clouds, but that, for the off-center collisions considered, non-axisymmetric instabilities are induced in those jets. Those instabilities grow faster for lower Mach number jets, and can produce disruptions substantially sooner than occurred in our earlier work on jets in the absence of collisions with massive clouds. Such interactions could be related to some Compact Steep Spectrum source morphologies. Very weak jets can be effectively halted by reasonably massive clouds, and this may have relevance for the paucity of radio jets in spiral galaxies. Slow, dense jets may be bent, yet remain stable for fairly extended times, thereby explaining some Wide-Angle-Tail and most "dog-leg" morphologies.

  13. Radio Jet Interactions with Massive Clouds

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Wiita, P. J.; Joyce, J.; Hooda, J. S.

    1998-12-01

    Rather high resolution three-dimensional simulations of hydrodynamical jets are computed using the Zeus-3D code. The parameters we employ are suitable for moderate to high power radio jets emerging through a galactic atmosphere or halo, and eventually crossing a tilted pressure matched interface with a hotter intracluster medium. Before they cross this interface, these simulations aim the jets so that they hit massive clouds within the galactic halo, with densities 10 or more times higher than the ambient atmospheric density, and 100's of times the jet density. Such clouds are set up with radii several times that of the jet, and could correspond to giant molecular cloud complexes or small cannibalized galaxies. We find that powerful jets eventually disperse the clouds, but that, for off-center collisions, non-axisymmetric instabilities are induced in those jets. Those instabilities grow faster for lower Mach number jets, and can produce disruptions substantially sooner than occurred in our earlier work on jets crossing tilted interfaces in the absence of collisions with massive clouds. Such interactions, particularly with weaker jets, could be related to some Compact Steep Spectrum source morphologies. Very weak jets can be effectively halted by reasonably massive clouds, and this may have relevance for the paucity of radio jets in spiral galaxies. The possibility of jets being bent, yet remaining stable, after such collisions is also investigated. This work was supported by NPACI allocation GSU200 on the Cray T90 and by RPE funds at Georgia State University.

  14. Massive suprachoroidal hemorrhage: Surgical management and outcome

    PubMed Central

    Laube, Thomas; Brockmann, Claudia; Bornfeld, Norbert

    2015-01-01

    Objective: To describe options for vitreoretinal surgery in the management of massive suprachoroidal hemorrhage (SCH). Methods: Visual acuity (VA), ocular findings, timing of surgical intervention, surgical procedures, and outcomes of four patients diagnosed with massive SCH and admitted to the University Eye Clinic Essen were reviewed retrospectively. Results: Four eyes of four patients (mean age, 82 years; range, 74–89 years) were studied. In three cases the occurrence of SCH was related to cataract surgery and occurred intra- or postoperatively. One patient developed spontaneous SCH of unclear origin. Three patients had a history of arterial hypertension; one eye had high myopia, two patients suffered from cardiovascular diseases, and two patients had glaucoma. Postoperative follow up of the patients ranged from 5 to 29.5 months (mean, 19.6 months). Transscleral drainage of SCH was in all cases combined with pars plana vitrectomy, use of heavy liquids (perfluorodecalin) and silicone oil tamponade. The mean time interval from hemorrhage to surgical intervention was 16.5 days (range 5–29 days). Preoperative VA of all eyes was light perception. Two patients achieved a final postoperative visual acuity of 20/20 and 20/320, respectively, one patient improved to hand motion, and one patient resulted in no light perception. Conclusions: Surgical interventions including transscleral drainage of SCH, vitrectomy, and silicone oil tamponade are valuable options in the management of massive SCH to save the eye and possibly improve the otherwise extreme poor prognosis.

  15. Cosmology in general massive gravity theories

    SciTech Connect

    Comelli, D.; Nesti, F.; Pilo, L. E-mail: fabrizio.nesti@aquila.infn.it

    2014-05-01

    We study the cosmological FRW flat solutions generated in general massive gravity theories. Such a model are obtained adding to the Einstein General Relativity action a peculiar non derivative potentials, function of the metric components, that induce the propagation of five gravitational degrees of freedom. This large class of theories includes both the case with a residual Lorentz invariance as well as the case with rotational invariance only. It turns out that the Lorentz-breaking case is selected as the only possibility. Moreover it turns out that that perturbations around strict Minkowski or dS space are strongly coupled. The upshot is that even though dark energy can be simply accounted by massive gravity modifications, its equation of state w{sub eff} has to deviate from -1. Indeed, there is an explicit relation between the strong coupling scale of perturbations and the deviation of w{sub eff} from -1. Taking into account current limits on w{sub eff} and submillimiter tests of the Newton's law as a limit on the possible strong coupling scale, we find that it is still possible to have a weakly coupled theory in a quasi dS background. Future experimental improvements on short distance tests of the Newton's law may be used to tighten the deviation of w{sub eff} form -1 in a weakly coupled massive gravity theory.

  16. VLT/X-shooter spectroscopy of massive pre-main-sequence stars in M17

    NASA Astrophysics Data System (ADS)

    Ramirez-Tannus, Maria Claudia; Kaper, Lex

    2015-08-01

    The formation process of massive stars is still poorly understood. Formation timescales are short, the corresponding accretion rates very high, and the forming stars are hidden from view due to vast amounts of interstellar extinction. On top of that, massive stars are rare, are located at relatively large distances, and play a major role in shaping the interstellar medium due to their strong UV radiation fields and stellar winds. Although massive stars show most spectral features in the UV and optical range, so far only for a handful of massive Young Stellar Objects (mYSOs) optical and near-infrared spectra have been obtained. For some of these their pre-main-sequence (PMS) nature has now been firmly established (e.g. Ochsendorf et al. 2011, Ellerbroek et al. 2013). The objective of our project is to determine the physical properties of mYSOs, to search for signatures remnant of their formation process and to better understand the feedback on their environment.To this aim the optical to near-infrared (300-2500 nm) spectra of six candidate mYSOs (Hanson et al. 1997), deeply embedded in the massive star forming region M17, have been obtained with X-Shooter on the ESO Very Large Telescope. These mYSO candidates have been identified based on their infrared excess and spectral features (double-peaked emission lines, CO band-head emission) indicating the presence of a disk. In most cases, we detect a photospheric spectrum allowing us to measure the physical properties of the mYSO and to confirm its PMS nature. We also uncover many emission features, including forbidden lines, providing information on the (active) formation process of these young (massive) stars.

  17. R144: a very massive binary likely ejected from R136 through a binary-binary encounter

    NASA Astrophysics Data System (ADS)

    Oh, Seungkyung; Kroupa, Pavel; Banerjee, Sambaran

    2014-02-01

    R144 is a recently confirmed very massive, spectroscopic binary which appears isolated from the core of the massive young star cluster R136. The dynamical ejection hypothesis as an origin for its location is claimed improbable by Sana et al. due to its binary nature and high mass. We demonstrate here by means of direct N-body calculations that a very massive binary system can be readily dynamically ejected from an R136-like cluster, through a close encounter with a very massive system. One out of four N-body cluster models produces a dynamically ejected very massive binary system with a mass comparable to R144. The system has a system mass of ≈355 M⊙ and is located at 36.8 pc from the centre of its parent cluster, moving away from the cluster with a velocity of 57 km s-1 at 2 Myr as a result of a binary-binary interaction. This implies that R144 could have been ejected from R136 through a strong encounter with another massive binary or single star. In addition, we discuss all massive binaries and single stars which are ejected dynamically from their parent cluster in the N-body models.

  18. On General Relativity with Massive Graviton

    NASA Astrophysics Data System (ADS)

    Berezhiani, Lasha

    We begin this thesis by studying the properties of horizons in the de Rham-Gabadadze-Tolley model of massive GR. In massive gravity the generic black hole (BH) solutions on Minkowski space happen to convert horizons into a certain type of singularities. Here we explore whether these singularities can be avoided if space-time is not asymptotically Minkowskian. We find an exact analytic BH solution which evades the above problem by a transition at large scales to self-induced de Sitter (dS) space-time, with the curvature scale set by the graviton mass. The solution demonstrates that in massive GR, in the Schwarzschild coordinate system, a BH metric has to be accompanied by the Stückelberg fields with nontrivial backgrounds to prevent the horizons to convert into the singularities. We also find an analogous solution for a Reissner-Nordström BH on dS space. The second part concerns with the geometrical construction of massive gravity. Namely, the theory of gravity with an auxiliary extra dimension is known to give a ghost-free cubic completion of the Fierz-Pauli mass term in the decoupling limit. Yet, the theory propagates ghost in quartic order and beyond. Our work proposes a completion of the boundary condition in the auxiliary dimension that avoids ghosts order-by-order in the decoupling limit. Furthermore, we show that the multi-dimensional extension, with the rotationally invariant boundaries of the bulk, is equivalent to the model with a single auxiliary dimension. Therefore, all these constructions require the appropriate adjustment of the boundary condition. The other possible extension of the original model, by the Gauss-Bonnet term, is studied as well. In the last part we analyze the models known as "gravitational Higgs theories" against instabilities. We show that these models, although seemingly different from the effective field theories of massive gravity, are in fact equivalent to them. We also show the equivalence between the non-covariant mode

  19. Hydrodynamical simulations of realistic massive cluster populations

    NASA Astrophysics Data System (ADS)

    Barnes, David J.; Henson, Monique A.; Kay, Scott T.; McCarthy, Ian G.; Bahe, Yannick M.; Eagle Collaboration

    2015-09-01

    Galaxy clusters are seeded by density fluctuations in the early Universe and grow via hierarchical collapse to become the most massive virialised objects we observed today. They are powerful probes that study both cosmology and astrophysical processes. Their internal structure at the current epoch is the result of a non-trivial interplay between gravitational collapse and the energy fed into the intra-cluster medium (ICM) by star formation and active galactic nuclei (AGN). These processes shape the ICM during its formation at high redshift, but current observations of galaxy clusters are limited to z<0.5. The resolution and sensitivity of textit{Athena+} will allow it to study galaxy clusters in unprecedented detail. It will constrain cluster properties, such as its entropy, temperature and gas fraction, out to z˜2, enabling it to investigate the progenitors of today's massive clusters and observing the evolution of the properties of the ICM for the first time. Athena+ will produce a significant change in our understanding of the formation of galaxy clusters. Recently the theoretical modelling of clusters has advanced significantly and issues, such as the 'cooling catastophea', have been overcome by including feedback from star formation and AGN. We present the MAssive ClusterS and Intercluster Structures (MACSIS) project. The MACSIS project is a representative sample of 390 of galaxy clusters, with M_{FOF} > 10(15} M_{⊙) , re-simulated using the cosmo-OWLS model (Le Brun et al. 2014, McCarthy et al. in prep.) to extend it to the most massive and rarest objects. We demonstrate that this sample reproduces the scaling relations, with intrinsic scatter, observed with current instruments at low redshift. Under the hierarchical paradigm, the progenitors of these systems will be the first objects to collapse at high redshift and we examine to z=2 how the scaling relations of these massive objects evolve with redshift. Finally, we investigate methods of defining a

  20. Massive Stars in the Quintuplet Cluster

    NASA Astrophysics Data System (ADS)

    Figer, Donald F.; McLean, Ian S.; Morris, Mark

    1999-03-01

    We present near-infrared photometry and K-band spectra of newly identified massive stars in the Quintuplet cluster, one of the three massive clusters projected within 50 pc of the Galactic center. We find that the cluster contains a variety of massive stars, including more unambiguously identified Wolf-Rayet stars than any cluster in the Galaxy, and over a dozen stars in earlier stages of evolution, i.e., luminous blue variables (LBVs), Ofpe/WN9, and OB supergiants. One newly identified star is the second luminous blue variable in the cluster, after the ``Pistol star.'' Although we are unable to provide certain spectral classifications for the five enigmatic Quintuplet-proper members, we tentatively propose that they are extremely dusty versions of the WC stars found elsewhere in the cluster and similar to the dozen or so known examples in the Galaxy. Although the cluster parameters are uncertain because of photometric errors and uncertainties in stellar models, i.e., extrapolating initial masses and estimating ionizing fluxes, we have the following conclusions. Given the evolutionary stages of the identified stars, the cluster appears to be about 4+/-1 Myr old, assuming coeval formation. The total mass in observed stars is ~103 Msolar, and the implied mass is ~104 Msolar, assuming a lower mass cutoff of 1 Msolar and a Salpeter initial mass function. The implied mass density in stars is greater than or similar to a few thousand Msolar pc-3. The newly identified stars increase the estimated ionizing flux from this cluster by about an order of magnitude with respect to earlier estimates, to 1050.9 photons s-1, or roughly what is required to ionize the nearby ``Sickle'' H II region (G0.18-0.04). The total luminosity from the massive cluster stars is ~107.5 Lsolar, enough to account for the heating of the nearby molecular cloud, M0.20-0.033. We propose a picture that integrates most of the major features in this part of the sky, excepting the nonthermal filaments. We

  1. Pre-heating in the framework of massive gravity

    NASA Astrophysics Data System (ADS)

    Maity, Debaprasad

    2016-09-01

    In this paper we propose a mechanism of natural pre-heating of our universe by introducing an inflaton field dependent mass term for the gravitational wave for a specific class of massive gravity theory. For any single field inflationary model, the inflaton must go through the oscillatory phase after the end of inflation. As has recently been pointed out, if the gravitational fluctuation has inflaton dependent mass term, there will be a resonant amplification of the amplitude of the gravitational wave during the oscillatory phase of inflaton. Because of this large enhancement of the amplitude of the gravitational wave due to parametric resonance, we show that universe can naturally go through the pre-reheated phase with minimally coupled matter field. Therefore, during the reheating phase, there is no need to introduce any arbitrary coupling between the matter field and the inflaton.

  2. Nanowire growth by an electron beam induced massive phase transformation

    DOE PAGES

    Sood, Shantanu; Kisslinger, Kim; Gouma, Perena

    2014-11-15

    Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stablemore » growth mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.« less

  3. Extracorporeal membrane oxygenation with danaparoid sodium after massive pulmonary embolism.

    PubMed

    Bauer, Christian; Vichova, Zuzana; Ffrench, Patrick; Hercule, Christiane; Jegaden, Olivier; Bastien, Olivier; Lehot, Jean-Jacques

    2008-04-01

    During extracorporeal membrane oxygenation, anticoagulation therapy is usually achieved with unfractionated heparin. We report on an extracorporeal membrane oxygenation with danaparoid sodium for a patient with severe respiratory failure due to massive pulmonary embolism and suspected type 2 heparin-induced thrombocytopenia. Danaparoid, a low molecular weight heparinoid, is an alternative to heparin for patients who develop type 2 heparin-induced thrombocytopenia. Danaparoid was given at 400 IU/h with an objective of antifactor Xa activity of 0.6-0.8 U/mL, which was monitored twice a day. No excessive bleeding or clotting of the circuit was noted. The patient was weaned from extracorporeal membrane oxygenation after 9 days of treatment. PMID:18349178

  4. Nanowire growth by an electron beam induced massive phase transformation

    SciTech Connect

    Sood, Shantanu; Kisslinger, Kim; Gouma, Perena

    2014-11-15

    Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stable growth mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.

  5. MASSIVE TRANSFUSION PROTOCOL: STANDARDIZING CARE TO IMPROVE PATIENT OUTCOMES.

    PubMed

    Porteous, Joan

    2015-06-01

    Providing rapid response is a primary goal when caring for surgical patients with injuries involving massive blood loss. Massive transfusion protocols have been developed in some tertiary care health care facilities to ensure a rapid and efficient response in the provision of care to patients with a massive and uncontrolled hemorrhage. The purpose of this article is to discuss a massive transfusion protocol and to describe the process used to implement a massive transfusion protocol at Winnipeg's Health Sciences Centre (the site) as well as to describe its impact in the operating room department. PMID:26310036

  6. MASSIVE TRANSFUSION PROTOCOL: STANDARDIZING CARE TO IMPROVE PATIENT OUTCOMES.

    PubMed

    Porteous, Joan

    2015-06-01

    Providing rapid response is a primary goal when caring for surgical patients with injuries involving massive blood loss. Massive transfusion protocols have been developed in some tertiary care health care facilities to ensure a rapid and efficient response in the provision of care to patients with a massive and uncontrolled hemorrhage. The purpose of this article is to discuss a massive transfusion protocol and to describe the process used to implement a massive transfusion protocol at Winnipeg's Health Sciences Centre (the site) as well as to describe its impact in the operating room department.

  7. Hyper-Eddington accretion flows on to massive black holes

    NASA Astrophysics Data System (ADS)

    Inayoshi, Kohei; Haiman, Zoltán; Ostriker, Jeremiah P.

    2016-07-01

    We study very high rate, spherically symmetric accretion flows on to massive black holes (BHs; 102 ≲ MBH ≲ 106 M⊙) embedded in dense metal-poor clouds, performing one-dimensional radiation hydrodynamical simulations. We find solutions from outside the Bondi radius at hyper-Eddington rates, unimpeded by radiation feedback when (n∞/105 cm-3) > (MBH/104 M⊙)-1(T∞/104 K)3/2, where n∞ and T∞ are the density and temperature of ambient gas. Accretion rates in this regime are steady, and larger than 5000LEdd/c2, where LEdd is the Eddington luminosity. At lower Bondi rates, the accretion is episodic due to radiative feedback and the average rate is below the Eddington rate. In the hyper-Eddington case, the solution consists of a radiation-dominated central core, where photon trapping due to electron scattering is important, and an accreting envelope which follows a Bondi profile with T ≃ 8000 K. When the emergent luminosity is limited to ≲ LEdd because of photon trapping, radiation from the central region does not affect the gas dynamics at larger scales. We apply our result to the rapid formation of massive BHs in protogalaxies with a virial temperature of Tvir ≳ 104K. Once a seed BH forms at the centre of the galaxy, it can grow to a maximum ˜105(Tvir/104 K) M⊙ via gas accretion independent of the initial BH mass. Finally, we discuss possible observational signatures of rapidly accreting BHs with/without allowance for dust. We suggest that these systems could explain Lyα emitters without X-rays and nearby luminous infrared sources with hot dust emission, respectively.

  8. The Clustering of Massive Galaxies in the Early Universe

    NASA Astrophysics Data System (ADS)

    Quadri, Ryan

    2009-01-01

    Until recently it was thought that the early universe was dominated by low-mass galaxies undergoing rapid star formation. But deep near-infrared (NIR) surveys have uncovered a population of red, massive galaxies at z=2-3 with a wide range of star formation rates. This talk is concerned with the identification and analysis of red galaxies at these redshifts, and particularly with their clustering properties. First, we present deep NIR imaging from the Multiwavelength Survey by Yale-Chile (MUSYC). These data are used to assess differences between several sets of selection criteria that are commonly used to identify distant galaxies, including the J-K>2.3 criterion for distant red galaxies (DRGs). Next, we present MUSYC results for galaxy clustering at z 2.5. While the broad population of NIR-selected galaxies clusters similarly to the low-mass, star-forming galaxies found in previous surveys, the reddest galaxies have much higher correlation lengths. This suggests that a color-density relationship was in place at these redshifts. We use the clustering results to estimate the mass of the dark matter halos that host NIR-selected galaxies. We find that the reddest galaxies, which include DRGs, significantly outnumber the halos that are massive enough to host them. This suggests that the observations may be incompatible with the models. To test whether this discrepancy is an artifact due to limited field size, we also investigate the clustering of DRGs in the larger UKIDSS Ultra-Deep Survey, but the models remain inconsistent with the observations. The disagreement could be due to inaccurate photometric redshifts or to incorrect models. An explanation for this disagreement will result in a more complete understanding of the relationship between different galaxy populations, and of the relationship between galaxy evolution and dark matter.

  9. Hawking radiation and the boomerang behavior of massive modes near a horizon

    SciTech Connect

    Jannes, G.; Maiessa, P.; Rousseaux, G.; Philbin, T. G.

    2011-05-15

    We discuss the behavior of massive modes near a horizon based on a study of the dispersion relation and wave packet simulations of the Klein-Gordon equation. We point out an apparent paradox between two (in principle equivalent) pictures of black-hole evaporation through Hawking radiation. In the picture in which the evaporation is due to the emission of positive-energy modes, one immediately obtains a threshold for the emission of massive particles. In the picture in which the evaporation is due to the absorption of negative-energy modes, such a threshold apparently does not exist. We resolve this paradox by tracing the evolution of the positive-energy massive modes with an energy below the threshold. These are seen to be emitted and move away from the black-hole horizon, but they bounce back at a 'red horizon' and are reabsorbed by the black hole, thus compensating exactly for the difference between the two pictures. For astrophysical black holes, the consequences are curious but do not affect the terrestrial constraints on observing Hawking radiation. For analogue-gravity systems with massive modes, however, the consequences are crucial and rather surprising.

  10. Arteriovenous malformation of the base of tongue in pregnancy: case report

    PubMed Central

    Martines, F; Immordino, V

    2009-01-01

    Summary Arteriovenous malformation of the head and neck is a rare vascular anomaly but when present is persistent and progressive in nature and can represent a lethal benign disease. An unusual case is presented of an arteriovenous malformation of the base of tongue in a 32-year-old primigravida at 23.2 weeks of gestation with a history of haemoptysis. The patient was admitted to hospital with 10.7 g/dl of haemoglobin and 32.1% of haematocrit but due to recurrent massive haemoptysis, in the next few days, dropped to 6.7 g/dl of haemoglobin and 20.2% of haematocrit which required immediate blood transfusions. To maintain the upper airways patent the patient underwent tracheostomy; during angiography, showing an arteriovenous malformation with its feeding arteries (lingual artery, internal maxillary artery, and maxillary artery) embolization was made without a significant blood flow reduction. After surgical ligation of the external carotid artery, on the right side, the patient was readmitted for further angiographic evaluation, which confirmed complete occlusion of the carotid artery but, at the same time, revealed the integrity of the arteriovenous malformation perfusion on account of a new feeding artery (left lingual artery). A new superselective catheterization of the lingual artery was performed but due to the effect of progesterone, which causes smooth muscle relaxation and leads to arteriovenous malformation dilatation and rupture, the primigravida again presented haemoptysis. In agreement with the gynaecologists, the patient was given betamethasone to induce foetal lung maturation, and induction of labour was planned at 26 weeks, and a healthy baby was delivered naturally. Over the following days, the patient had no further haemoptysis and so far clinical examination showed no evidence of the original mass (slight haemorrhagic suffusion of the right anterior amygdale region). PMID:20162030

  11. Birth of Massive Black Hole Binaries

    SciTech Connect

    Colpi, M.; Dotti, M.; Mayer, L.; Kazantzidis, S.; /KIPAC, Menlo Park

    2007-11-19

    If massive black holes (BHs) are ubiquitous in galaxies and galaxies experience multiple mergers during their cosmic assembly, then BH binaries should be common albeit temporary features of most galactic bulges. Observationally, the paucity of active BH pairs points toward binary lifetimes far shorter than the Hubble time, indicating rapid inspiral of the BHs down to the domain where gravitational waves lead to their coalescence. Here, we review a series of studies on the dynamics of massive BHs in gas-rich galaxy mergers that underscore the vital role played by a cool, gaseous component in promoting the rapid formation of the BH binary. The BH binary is found to reside at the center of a massive self-gravitating nuclear disc resulting from the collision of the two gaseous discs present in the mother galaxies. Hardening by gravitational torques against gas in this grand disc is found to continue down to sub-parsec scales. The eccentricity decreases with time to zero and when the binary is circular, accretion sets in around the two BHs. When this occurs, each BH is endowed with it own small-size ({approx}< 0.01 pc) accretion disc comprising a few percent of the BH mass. Double AGN activity is expected to occur on an estimated timescale of {approx}< 1 Myr. The double nuclear point-like sources that may appear have typical separation of {approx}< 10 pc, and are likely to be embedded in the still ongoing starburst. We note that a potential threat of binary stalling, in a gaseous environment, may come from radiation and/or mechanical energy injections by the BHs. Only short-lived or sub-Eddington accretion episodes can guarantee the persistence of a dense cool gas structure around the binary necessary for continuing BH inspiral.

  12. Detecting Emotional Contagion in Massive Social Networks

    PubMed Central

    Coviello, Lorenzo; Sohn, Yunkyu; Kramer, Adam D. I.; Marlow, Cameron; Franceschetti, Massimo; Christakis, Nicholas A.; Fowler, James H.

    2014-01-01

    Happiness and other emotions spread between people in direct contact, but it is unclear whether massive online social networks also contribute to this spread. Here, we elaborate a novel method for measuring the contagion of emotional expression. With data from millions of Facebook users, we show that rainfall directly influences the emotional content of their status messages, and it also affects the status messages of friends in other cities who are not experiencing rainfall. For every one person affected directly, rainfall alters the emotional expression of about one to two other people, suggesting that online social networks may magnify the intensity of global emotional synchrony. PMID:24621792

  13. Body contouring following massive weight loss

    PubMed Central

    Langer, Vijay; Singh, Amitabh; Aly, Al S.; Cram, Albert E.

    2011-01-01

    Obesity is a global disease with epidemic proportions. Bariatric surgery or modified lifestyles go a long way in mitigating the vast weight gain. Patients following these interventions usually undergo massive weight loss. This results in redundant tissues in various parts of the body. Loose skin causes increased morbidity and psychological trauma. This demands various body contouring procedures that are usually excisional. These procedures are complex and part of a painstaking process that needs a committed patient and an industrious plastic surgeon. As complications in these patients can be quite frequent, both the patient and the surgeon need to be aware and willing to deal with them. PMID:21713202

  14. Covariant constraints in ghost free massive gravity

    SciTech Connect

    Deffayet, C.; Mourad, J.; Zahariade, G. E-mail: mourad@apc.univ-paris7.fr

    2013-01-01

    We show that the reformulation of the de Rham-Gabadadze-Tolley massive gravity theory using vielbeins leads to a very simple and covariant way to count constraints, and hence degrees of freedom. Our method singles out a subset of theories, in the de Rham-Gabadadze-Tolley family, where an extra constraint, needed to eliminate the Boulware Deser ghost, is easily seen to appear. As a side result, we also introduce a new method, different from the Stuckelberg trick, to extract kinetic terms for the polarizations propagating in addition to those of the massless graviton.

  15. Massive Preperitoneal Hematoma after a Subcutaneous Injection

    PubMed Central

    Yoshikawa, Kentaro; Lefor, Alan Kawarai; Kubota, Tadao; Mizokami, Ken

    2016-01-01

    Preperitoneal hematomas are rare and can develop after surgery or trauma. A 74-year-old woman, receiving systemic anticoagulation, developed a massive preperitoneal hematoma after a subcutaneous injection of teriparatide using a 32-gauge, 4 mm needle. In this patient, there were two factors, the subcutaneous injection of teriparatide and systemic anticoagulation, associated with development of the hematoma. These two factors are especially significant, because they are widely used clinically. Although extremely rare, physicians must consider this potentially life-threatening complication after subcutaneous injections, especially in patients receiving anticoagulation. PMID:27738545

  16. Towards Realistic Modeling of Massive Star Clusters

    NASA Astrophysics Data System (ADS)

    Gnedin, O.; Li, H.

    2016-06-01

    Cosmological simulations of galaxy formation are rapidly advancing towards smaller scales. Current models can now resolve giant molecular clouds in galaxies and predict basic properties of star clusters forming within them. I will describe new theoretical simulations of the formation of the Milky Way throughout cosmic time, with the adaptive mesh refinement code ART. However, many challenges - physical and numerical - still remain. I will discuss how observations of massive star clusters and star forming regions can help us overcome some of them. Video of the talk is available at https://goo.gl/ZoZOfX

  17. Spontaneous Massive Adrenal Hemorrhage: A Management Dilemma

    PubMed Central

    Agarwal, Anshuman

    2015-01-01

    Abstract Adrenal hemorrhage (AH) is a rare but life-threatening condition. Small focal hemorrhage may present subclinically, but massive hemorrhage may lead to rapid cardiovascular collapse and ultimately death if not diagnosed appropriately and treated quickly. Most cases reported in the literature have been treated conservatively. In an event of increasing hemorrhage during conservative management, it may be tricky to intervene surgically because of the hematoma around the gland. Here we describe a case where we managed a large spontaneous AH by a combination of angioembolization and laparoscopic adrenalectomy.

  18. Spontaneous Massive Adrenal Hemorrhage: A Management Dilemma

    PubMed Central

    Agarwal, Anshuman

    2015-01-01

    Abstract Adrenal hemorrhage (AH) is a rare but life-threatening condition. Small focal hemorrhage may present subclinically, but massive hemorrhage may lead to rapid cardiovascular collapse and ultimately death if not diagnosed appropriately and treated quickly. Most cases reported in the literature have been treated conservatively. In an event of increasing hemorrhage during conservative management, it may be tricky to intervene surgically because of the hematoma around the gland. Here we describe a case where we managed a large spontaneous AH by a combination of angioembolization and laparoscopic adrenalectomy. PMID:27579389

  19. Investigations in massive 3D gravity

    SciTech Connect

    Accioly, Antonio; Helayeel-Neto, Jose; Morais, Jefferson; Turcati, Rodrigo; Scatena, Eslley

    2011-05-15

    Some interesting gravitational properties of the Bergshoeff-Hohm-Townsend model (massive 3D gravity), such as the presence of a short-range gravitational force in the nonrelativistic limit and the existence of an impact-parameter-dependent gravitational deflection angle, are studied. Interestingly enough, these phenomena have no counterpart in the usual Einstein 3D gravity. In order to better understand the two aforementioned gravitational properties, they are also analyzed in the framework of 3D higher-derivative gravity with the Einstein-Hilbert term with the 'wrong sign'.

  20. Searching for Massive Photons with Ion Interferometry

    NASA Astrophysics Data System (ADS)

    Durfee, Dallin; Neyenhuis, Brian; Christensen, Dan

    2008-05-01

    We will discuss an ion interferometer under construction that should enable the detection of a possible photon rest mass more than 100 times smaller than previous laboratory experiments. In the apparatus a beam of ^87Sr^+ ions will be split and recombined using stimulated Raman transitions inside of a conducting cylinder. Deviations from Coulomb's law can then be detected by measuring the phase shift of the interferometer as the potential applied to the conducting cylinder is changed. We will discuss both the details of the device and the theory connecting deviations from Coulomb's inverse-square law to a theory of massive photons.

  1. Instability considerations for massive star eruptions

    SciTech Connect

    Guzik, J. A.

    2004-01-01

    We propose a mechanism to explain the observed properties of the giant eruptions of 'supernova imposters' such as {eta} Car and P Cyg. This mechanism must be episodic, generate a large amount of energy, and be very deep-seated, in order to lift about 10 solar masses out of the deep gravitational potential well of these massive evolved stars. We suggest that nonradial gravity mode oscillations capable of existing in the core grow slowly to sufficient amplitude to cause an episode of mixing. This mixing generates a burst of nuclear energy deep in the star that is responsible for the observed large mass ejection and bolometric magnitude increase.

  2. A massive early atmosphere on Triton

    NASA Technical Reports Server (NTRS)

    Lunine, Jonathan I.; Nolan, Michael C.

    1992-01-01

    The idea of an early greenhouse atmosphere for Triton is presented and the conditions under which it may have been sustained are quantified. The volatile content of primordial Triton is modeled, and tidal heating rates are assessed to set bounds on the available energy. The atmospheric model formalism is presented, and it is shown how a massive atmosphere could have been raised by modest tidal heating fluxes. The implications of the model atmospheres for the atmospheric escape rates, the chemical evolution, and the cratering record are addressed.

  3. A new quasidilaton theory of massive gravity

    SciTech Connect

    Mukohyama, Shinji

    2014-12-01

    We present a new quasidilaton theory of Poincare invariant massive gravity, based on the recently proposed framework of matter coupling that makes it possible for the kinetic energy of the quasidilaton scalar to couple to both physical and fiducial metrics simultaneously. We find a scaling-type exact solution that expresses a self-accelerating de Sitter universe, and then analyze linear perturbations around it. It is shown that in a range of parameters all physical degrees of freedom have non-vanishing quadratic kinetic terms and are stable in the subhorizon limit, while the effective Newton's constant for the background is kept positive.

  4. Treatment of massive haematuria with aluminous salts.

    PubMed

    Arrizabalaga, M; Extramiana, J; Parra, J L; Ramos, C; Díaz González, R; Leiva, O

    1987-09-01

    Fifteen patients with massive vesical haematuria were treated with a 1% aluminium potassium sulphate solution in sterile distilled water, using continuous intravesical lavage with a double channel catheter. The haematuria was caused by vesical tumours in 13 patients, radiation cystitis in one and transurethral resection in one. Immediate side effects were few and none were noted in the long term, as judged by randomised biopsies from vesical mucosa. A complete response was noted in 66% of the patients, partial response in 15% and failure in 20%. This treatment is recommended for intractable bleeding from radiation cystitis and bladder tumours. PMID:3676666

  5. The exceptional story of massive IIA supergravity

    NASA Astrophysics Data System (ADS)

    Ciceri, Franz; Guarino, Adolfo; Inverso, Gianluca

    2016-08-01

    The framework of exceptional field theory is extended by introducing consistent deformations of its generalised Lie derivative. For the first time, massive type IIA super-gravity is reproduced geometrically as a solution of the section constraint. This provides a unified description of all ten- and eleven-dimensional maximal supergravities. The actionof the E7(7) deformed theory is constructed, and reduces to those of exceptional field theory and gauged maximal supergravity in respective limits. The relation of this new framework to other approaches for generating the Romans mass non-geometrically is discussed.

  6. The Evolution and Stability of Massive Stars

    NASA Astrophysics Data System (ADS)

    Shiode, Joshua Hajime

    Massive stars are the ultimate source for nearly all the elements necessary for life. The first stars forge these elements from the sparse set of ingredients supplied by the Big Bang, and distribute enriched ashes throughout their galactic homes via their winds and explosive deaths. Subsequent generations follow suit, assembling from the enriched ashes of their predecessors. Over the last several decades, the astrophysics community has developed a sophisticated theoretical picture of the evolution of these stars, but it remains an incomplete accounting of the rich set of observations. Using state of the art models of massive stars, I have investigated the internal processes taking place throughout the life-cycles of stars spanning those from the first generation ("Population III") to the present-day ("Population I"). I will argue that early-generation stars were not highly unstable to perturbations, contrary to a host of past investigations, if a correct accounting is made for the viscous effect of convection. For later generations, those with near solar metallicity, I find that this very same convection may excite gravity-mode oscillations that produce observable brightness variations at the stellar surface when the stars are near the main sequence. If confirmed with modern high-precision monitoring experiments, like Kepler and CoRoT, the properties of observed gravity modes in massive stars could provide a direct probe of the poorly constrained physics of gravity mode excitation by convection. Finally, jumping forward in stellar evolutionary time, I propose and explore an entirely new mechanism to explain the giant eruptions observed and inferred to occur during the final phases of massive stellar evolution. This mechanism taps into the vast nuclear fusion luminosity, and accompanying convective luminosity, in the stellar core to excite waves capable of carrying a super-Eddington luminosity out to the stellar envelope. This energy transfer from the core to the

  7. Spitzer view of massive star formation in the tidally stripped Magellanic Bridge

    SciTech Connect

    Chen, C.-H. Rosie; Indebetouw, Remy; Muller, Erik; Kawamura, Akiko; Gordon, Karl D.; Meixner, Margaret; Seale, Jonathan P.; Shiao, Bernie; Sewiło, Marta; Whitney, Barbara A.; Meade, Marilyn R.; Fukui, Yasuo; Madden, Suzanne C.; Robitaille, Thomas P.

    2014-04-20

    The Magellanic Bridge is the nearest low-metallicity, tidally stripped environment, offering a unique high-resolution view of physical conditions in merging and forming galaxies. In this paper, we present an analysis of candidate massive young stellar objects (YSOs), i.e., in situ, current massive star formation (MSF) in the Bridge using Spitzer mid-IR and complementary optical and near-IR photometry. While we definitely find YSOs in the Bridge, the most massive are ∼10 M {sub ☉}, <<45 M {sub ☉} found in the LMC. The intensity of MSF in the Bridge also appears to be decreasing, as the most massive YSOs are less massive than those formed in the past. To investigate environmental effects on MSF, we have compared properties of massive YSOs in the Bridge to those in the LMC. First, YSOs in the Bridge are apparently less embedded than in the LMC: 81% of Bridge YSOs show optical counterparts, compared to only 56% of LMC sources with the same range of mass, circumstellar dust mass, and line-of-sight extinction. Circumstellar envelopes are evidently more porous or clumpy in the Bridge's low-metallicity environment. Second, we have used whole samples of YSOs in the LMC and the Bridge to estimate the probability of finding YSOs at a given H I column density, N(H I). We found that the LMC has ∼3 × higher probability than the Bridge for N(H I) >12 × 10{sup 20} cm{sup –2}, but the trend reverses at lower N(H I). Investigating whether this lower efficiency relative to H I is due to less efficient molecular cloud formation or to less efficient cloud collapse, or to both, will require sensitive molecular gas observations.

  8. Spitzer View of Massive Star Formation in the Tidally Stripped Magellanic Bridge

    NASA Astrophysics Data System (ADS)

    Chen, C.-H. Rosie; Indebetouw, Remy; Muller, Erik; Kawamura, Akiko; Gordon, Karl D.; Sewiło, Marta; Whitney, Barbara A.; Fukui, Yasuo; Madden, Suzanne C.; Meade, Marilyn R.; Meixner, Margaret; Oliveira, Joana M.; Robitaille, Thomas P.; Seale, Jonathan P.; Shiao, Bernie; van Loon, Jacco Th.

    2014-04-01

    The Magellanic Bridge is the nearest low-metallicity, tidally stripped environment, offering a unique high-resolution view of physical conditions in merging and forming galaxies. In this paper, we present an analysis of candidate massive young stellar objects (YSOs), i.e., in situ, current massive star formation (MSF) in the Bridge using Spitzer mid-IR and complementary optical and near-IR photometry. While we definitely find YSOs in the Bridge, the most massive are ~10 M ⊙, Lt45 M ⊙ found in the LMC. The intensity of MSF in the Bridge also appears to be decreasing, as the most massive YSOs are less massive than those formed in the past. To investigate environmental effects on MSF, we have compared properties of massive YSOs in the Bridge to those in the LMC. First, YSOs in the Bridge are apparently less embedded than in the LMC: 81% of Bridge YSOs show optical counterparts, compared to only 56% of LMC sources with the same range of mass, circumstellar dust mass, and line-of-sight extinction. Circumstellar envelopes are evidently more porous or clumpy in the Bridge's low-metallicity environment. Second, we have used whole samples of YSOs in the LMC and the Bridge to estimate the probability of finding YSOs at a given H I column density, N(H I). We found that the LMC has ~3 × higher probability than the Bridge for N(H I) >12 × 1020 cm-2, but the trend reverses at lower N(H I). Investigating whether this lower efficiency relative to H I is due to less efficient molecular cloud formation or to less efficient cloud collapse, or to both, will require sensitive molecular gas observations.

  9. Knowledge Discovery from Massive Healthcare Claims Data

    SciTech Connect

    Chandola, Varun; Sukumar, Sreenivas R; Schryver, Jack C

    2013-01-01

    The role of big data in addressing the needs of the present healthcare system in US and rest of the world has been echoed by government, private, and academic sectors. There has been a growing emphasis to explore the promise of big data analytics in tapping the potential of the massive healthcare data emanating from private and government health insurance providers. While the domain implications of such collaboration are well known, this type of data has been explored to a limited extent in the data mining community. The objective of this paper is two fold: first, we introduce the emerging domain of big"healthcare claims data to the KDD community, and second, we describe the success and challenges that we encountered in analyzing this data using state of art analytics for massive data. Specically, we translate the problem of analyzing healthcare data into some of the most well-known analysis problems in the data mining community, social network analysis, text mining, and temporal analysis and higher order feature construction, and describe how advances within each of these areas can be leveraged to understand the domain of healthcare. Each case study illustrates a unique intersection of data mining and healthcare with a common objective of improving the cost-care ratio by mining for opportunities to improve healthcare operations and reducing hat seems to fall under fraud, waste,and abuse.

  10. Dipolar dark matter with massive bigravity

    SciTech Connect

    Blanchet, Luc; Heisenberg, Lavinia

    2015-12-14

    Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because of the particular couplings of the matter fields and vector field to the metrics, a ghost in the decoupling limit is present in the dark matter sector. However, it might be possible to push the mass of the ghost beyond the strong coupling scale by an appropriate choice of the parameters of the model. Crucial questions to address in future work are the exact mass of the ghost, and the cosmological implications of the model.

  11. Planckian Interacting Massive Particles as Dark Matter.

    PubMed

    Garny, Mathias; Sandora, McCullen; Sloth, Martin S

    2016-03-11

    The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01M_{p} is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark matter.

  12. Fracture simulations via massively parallel molecular dynamics

    SciTech Connect

    Holian, B.L.; Abraham, F.F.; Ravelo, R.

    1993-09-01

    Fracture simulations at the atomistic level have heretofore been carried out for relatively small systems of particles, typically 10,000 or less. In order to study anything approaching a macroscopic system, massively parallel molecular dynamics (MD) must be employed. In two spatial dimensions (2D), it is feasible to simulate a sample that is 0.1 {mu}m on a side. We report on recent MD simulations of mode I crack extension under tensile loading at high strain rates. The method of uniaxial, homogeneously expanding periodic boundary conditions was employed to represent tensile stress conditions near the crack tip. The effects of strain rate, temperature, material properties (equation of state and defect energies), and system size were examined. We found that, in order to mimic a bulk sample, several tricks (in addition to expansion boundary conditions) need to be employed: (1) the sample must be pre-strained to nearly the condition at which the crack will spontaneously open; (2) to relieve the stresses at free surfaces, such as the initial notch, annealing by kinetic-energy quenching must be carried out to prevent unwanted rarefactions; (3) sound waves emitted as the crack tip opens and dislocations emitted from the crack tip during blunting must be absorbed by special reservoir regions. The tricks described briefly in this paper will be especially important to carrying out feasible massively parallel 3D simulations via MD.

  13. Linear Time Vertex Partitioning on Massive Graphs

    PubMed Central

    Mell, Peter; Harang, Richard; Gueye, Assane

    2016-01-01

    The problem of optimally removing a set of vertices from a graph to minimize the size of the largest resultant component is known to be NP-complete. Prior work has provided near optimal heuristics with a high time complexity that function on up to hundreds of nodes and less optimal but faster techniques that function on up to thousands of nodes. In this work, we analyze how to perform vertex partitioning on massive graphs of tens of millions of nodes. We use a previously known and very simple heuristic technique: iteratively removing the node of largest degree and all of its edges. This approach has an apparent quadratic complexity since, upon removal of a node and adjoining set of edges, the node degree calculations must be updated prior to choosing the next node. However, we describe a linear time complexity solution using an array whose indices map to node degree and whose values are hash tables indicating the presence or absence of a node at that degree value. This approach also has a linear growth with respect to memory usage which is surprising since we lowered the time complexity from quadratic to linear. We empirically demonstrate linear scalability and linear memory usage on random graphs of up to 15000 nodes. We then demonstrate tractability on massive graphs through execution on a graph with 34 million nodes representing Internet wide router connectivity. PMID:27336059

  14. Massive Star Formation: The Role of Disks

    NASA Astrophysics Data System (ADS)

    Fallscheer, Cassandra L.; Beuther, H.; Sauter, J.; Wolf, S.; Zhang, Q.; Keto, E.; Sridharan, T. K.

    2011-01-01

    We have obtained multiple data sets from the SMA, PdBI, and IRAM 30m telescope of the Infrared Dark Cloud IRDC18223-3, the High-Mass Protostellar Object IRAS18151-1208, and the hot core source IRAS18507+0121 in order to search for clues regarding the role of rotation and disks in high mass star formation. These three objects allow us to compare the central-most regions surrounding the embedded continuum source at three different evolutionary stages of the formation process. Toward all three regions we see rotational or elongated structures perpendicular to the molecular outflows. Similarities and differences in the evolutionary sequence are discussed in the context of core and disk evolution. We have also carried out continuum and line radiative transfer modeling of the disk-like structures. Having a more complete picture of the evolutionary process that a massive star experiences will contribute significantly to the future of massive star formation research. Support for this project comes from the Deutsche Forschungsgemeinschaft and the International Max-Planck Research School for Astronomy and Cosmic Physics at the University of Heidelberg.

  15. Massive Science with VO and Grids

    NASA Astrophysics Data System (ADS)

    Nichol, R.; Smith, G.; Miller, C.; Freeman, P.; Genovese, C.; Wasserman, L.; Bryan, B.; Gray, A.; Schneider, J.; Moore, A.

    2006-07-01

    There is a growing need for massive computational resources for the analysis of new astronomical datasets. To tackle this problem, we present here our first steps towards marrying two new and emerging technologies; the Virtual Observatory (e.g, AstroGrid) and the computational grid (e.g. TeraGrid, COSMOS etc.). We discuss the construction of VOTechBroker, which is a modular software tool designed to abstract the tasks of submission and management of a large number of computational jobs to a distributed computer system. The broker will also interact with the AstroGrid workflow and MySpace environments. We discuss our planned usages of the VOTechBroker in computing a huge number of n--point correlation functions from the SDSS data and massive model-fitting of millions of CMBfast models to WMAP data. We also discuss other applications including the determination of the XMM Cluster Survey selection function and the construction of new WMAP maps.

  16. Exact supersymmetric massive and massless white holes

    NASA Astrophysics Data System (ADS)

    Kallosh, Renata; Linde, Andrei

    1995-12-01

    We study special points in the moduli space of vacua at which supersymmetric electric solutions of the heterotic string theory become massless. We concentrate on configurations for which the supersymmetric nonrenormalization theorem is valid. These are ten-dimensional supersymmetric string waves and generalized fundamental strings with SO(8) holonomy group. From these we find the four-dimensional spherically symmetric configurations which saturate the BPS bound, in particular, near the points of the vanishing ADM mass. The nontrivial massless supersymmetric states in this class exist only in the presence of non-Abelian vector fields. We also find a new class of supersymmetric massive solutions, closely related to the massless ones. A distinctive property of all these objects, either massless or massive, is the existence of gravitational repulsion. They reflect all particles with nonvanishing mass and/or angular momentum, and therefore they can be called white holes (repulsons), in contrast with black holes which tend to absorb particles of all kinds. If such objects can exist we will have the first realization of the universal gravitational force which repels all particles with the strength proportional to their mass and therefore can be associated with antigravity.

  17. Massive obstetric hemorrhage: Current approach to management.

    PubMed

    Guasch, E; Gilsanz, F

    2016-01-01

    Massive obstetric hemorrhage is a major cause of maternal mortality and morbidity worldwide. It is defined (among others) as the loss of>2,500ml of blood, and is associated to a need for admission to critical care and/or hysterectomy. The relative hemodilution and high cardiac output found in normal pregnancy allows substantial bleeding before a drop in hemoglobin and/or hematocrit can be identified. Some comorbidities associated with pregnancy can contribute to the occurrence of catastrophic bleeding with consumption coagulopathy, which makes the situation even worse. Optimization, preparation, rational use of resources and protocolization of actions are often useful to improve outcomes in patients with postpartum hemorrhage. Using massive obstetric hemorrhage protocols is useful for facilitating rapid transfusion if needed, and can also be cost-effective. If hypofibrinogenemia during the bleeding episode is identified, early fibrinogen administration can be very useful. Other coagulation factors in addition to fibrinogen may be necessary during postpartum hemorrhage replacement measures in order to effectively correct coagulopathy. A hysterectomy is recommended if the medical and surgical measures prove ineffective. PMID:27184441

  18. Circumstellar bubble created by two massive stars

    NASA Astrophysics Data System (ADS)

    Meliani, Z.; van Marle, A. J.; Marcowith, A.

    2013-11-01

    The massive stars are formed in clusters then numerical models of wind-blown bubble should evolve bubble created by several stars. Aims. We develop a two-dimensional (2D) model of the circumstellar bubble created by two massive stars, a 40 M_{odot} star and a 25 M_{odot} star, and follow its evolution with MPI-AMRVAC hydrodynamics code until the end of the stellar evolution and he supernova explosion of each star. The stars are separated by approximately 16 pc and surrounded by a cold medium with a density of 20 particles per cm3. The simulations showed that the evolution of a wind-blown bubble created by two stars deviates from that of the bubbles around single stars. In particular, once one of the stars has exploded, the bubble is too large for the wind of the remaining star to maintain and the outer shell starts to disintegrate. The lack of thermal pressure inside the bubble also changes the behavior of circumstellar features close to the remaining star. The supernovae are contained inside the bubble, which reflects part of the energy back into the circumstellar medium.

  19. Planckian Interacting Massive Particles as Dark Matter.

    PubMed

    Garny, Mathias; Sandora, McCullen; Sloth, Martin S

    2016-03-11

    The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01M_{p} is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark matter. PMID:27015472

  20. Dipolar dark matter with massive bigravity

    SciTech Connect

    Blanchet, Luc; Heisenberg, Lavinia E-mail: laviniah@kth.se

    2015-12-01

    Massive gravity theories have been developed as viable IR modifications of gravity motivated by dark energy and the problem of the cosmological constant. On the other hand, modified gravity and modified dark matter theories were developed with the aim of solving the problems of standard cold dark matter at galactic scales. Here we propose to adapt the framework of ghost-free massive bigravity theories to reformulate the problem of dark matter at galactic scales. We investigate a promising alternative to dark matter called dipolar dark matter (DDM) in which two different species of dark matter are separately coupled to the two metrics of bigravity and are linked together by an internal vector field. We show that this model successfully reproduces the phenomenology of dark matter at galactic scales (i.e. MOND) as a result of a mechanism of gravitational polarisation. The model is safe in the gravitational sector, but because of the particular couplings of the matter fields and vector field to the metrics, a ghost in the decoupling limit is present in the dark matter sector. However, it might be possible to push the mass of the ghost beyond the strong coupling scale by an appropriate choice of the parameters of the model. Crucial questions to address in future work are the exact mass of the ghost, and the cosmological implications of the model.

  1. Probing Massive Star Cluster Formation with ALMA

    NASA Astrophysics Data System (ADS)

    Johnson, Kelsey

    2015-08-01

    Observationally constraining the physical conditions that give rise to massive star clusters has been a long-standing challenge. Now with the ALMA Observatory coming on-line, we can finally begin to probe the birth environments of massive clusters in a variety of galaxies with sufficient angular resolution. In this talk I will give an overview of ALMA observations of galaxies in which candidate proto-super star cluster molecular clouds have been identified. These new data probe the physical conditions that give rise to super star clusters, providing information on their densities, pressures, and temperatures. In particular, the observations indicate that these clouds may be subject to external pressures of P/k > 108 K cm-3, which is consistent with the prevalence of optically observed adolescent super star clusters in interacting galaxy systems and other high pressure environments. ALMA observations also enable an assessement of the molecular cloud chemical abundances in the regions surrounding super star clusters. Molecular clouds associated with existing super star clusters are strongly correlated with HCO+ emission, but appear to have relatively low ratio of CO/HCO+ emission compared to other clouds, indicating that the super star clusters are impacting the molecular abundances in their vicinity.

  2. Seismic imaging on massively parallel computers

    SciTech Connect

    Ober, C.C.; Oldfield, R.A.; Womble, D.E.; Mosher, C.C.

    1997-07-01

    A key to reducing the risks and costs associated with oil and gas exploration is the fast, accurate imaging of complex geologies, such as salt domes in the Gulf of Mexico and overthrust regions in US onshore regions. Pre-stack depth migration generally yields the most accurate images, and one approach to this is to solve the scalar-wave equation using finite differences. Current industry computational capabilities are insufficient for the application of finite-difference, 3-D, prestack, depth-migration algorithms. High performance computers and state-of-the-art algorithms and software are required to meet this need. As part of an ongoing ACTI project funded by the US Department of Energy, the authors have developed a finite-difference, 3-D prestack, depth-migration code for massively parallel computer systems. The goal of this work is to demonstrate that massively parallel computers (thousands of processors) can be used efficiently for seismic imaging, and that sufficient computing power exists (or soon will exist) to make finite-difference, prestack, depth migration practical for oil and gas exploration.

  3. Massive intrathoracic lipoma in men1 syndrome

    PubMed Central

    Sturiale, Alessandro; Giudici, Francesco; Alemanno, Giovanni; Cavalli, Tiziana; Addasi, Rami; Santomaggio, Carmine; Meoni, Giulia; Brandi, Maria Luisa; Tonelli, Francesco

    2014-01-01

    Introduction The multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant syndrome characterized by the onset of hyperparathyroidism, gastroenteropancreatic neuroendocrine tumors and pituitary lesions. Presentation of case This appears to be the first described case of a massive intrathoracic lipoma in MEN1. The patient was affected with primary hyperparathyroidism treated with a total parathyroidectomy followed by a distal pancreatectomy for insulinoma. At follow-up, the computed tomography showed a massive lesion on the left emithorax suggestive of a lipoma. At the onset of a mild dyspnea we decided to perform the surgical excision of the mass obtaining a complete relief of the symptoms. Discussion This case is evidence of the importance of a strict follow-up of such patients. Conclusion Lipomas are the most frequent benign soft tissue tumors. They are usually sporadic but are sometimes related to hereditary syndromes. Intrathoracic localizations are rare and can arise mainly in the mediastinum, bronchus or lung. The diagnosis is often incidental; despite preoperative imaging will accurately show the features of the lesions, it is impossible obtain an accurate diagnosis-hence, the treatment of choice remains the surgical excision. PMID:25545711

  4. METHYL CYANIDE OBSERVATIONS TOWARD MASSIVE PROTOSTARS

    SciTech Connect

    Rosero, V.; Hofner, P.; Kurtz, S.; Bieging, J.; Araya, E. D.

    2013-07-01

    We report the results of a survey in the CH{sub 3}CN J = 12 {yields} 11 transition toward a sample of massive proto-stellar candidates. The observations were carried out with the 10 m Submillimeter Telescope on Mount Graham, AZ. We detected this molecular line in 9 out of 21 observed sources. In six cases this is the first detection of this transition. We also obtained full beam sampled cross-scans for five sources which show that the lower K-components can be extended on the arcminute angular scale. The higher K-components, however, are always found to be compact with respect to our 36'' beam. A Boltzmann population diagram analysis of the central spectra indicates CH{sub 3}CN column densities of about 10{sup 14} cm{sup -2}, and rotational temperatures above 50 K, which confirms these sources as hot molecular cores. Independent fits to line velocity and width for the individual K-components resulted in the detection of an increasing blueshift with increasing line excitation for four sources. Comparison with mid-infrared (mid-IR) images from the SPITZER GLIMPSE/IRAC archive for six sources show that the CH{sub 3}CN emission is generally coincident with a bright mid-IR source. Our data clearly show that the CH{sub 3}CN J = 12 {yields} 11 transition is a good probe of the hot molecular gas near massive protostars, and provide the basis for future interferometric studies.

  5. Planckian Interacting Massive Particles as Dark Matter

    NASA Astrophysics Data System (ADS)

    Garny, Mathias; Sandora, McCullen; Sloth, Martin S.

    2016-03-01

    The standard model could be self-consistent up to the Planck scale according to the present measurements of the Higgs boson mass and top quark Yukawa coupling. It is therefore possible that new physics is only coupled to the standard model through Planck suppressed higher dimensional operators. In this case the weakly interacting massive particle miracle is a mirage, and instead minimality as dictated by Occam's razor would indicate that dark matter is related to the Planck scale, where quantum gravity is anyway expected to manifest itself. Assuming within this framework that dark matter is a Planckian interacting massive particle, we show that the most natural mass larger than 0.01 Mp is already ruled out by the absence of tensor modes in the cosmic microwave background (CMB). This also indicates that we expect tensor modes in the CMB to be observed soon for this type of minimal dark matter model. Finally, we touch upon the Kaluza-Klein graviton mode as a possible realization of this scenario within UV complete models, as well as further potential signatures and peculiar properties of this type of dark matter candidate. This paradigm therefore leads to a subtle connection between quantum gravity, the physics of primordial inflation, and the nature of dark matter.

  6. Human due diligence.

    PubMed

    Harding, David; Rouse, Ted

    2007-04-01

    Most companies do a thorough job of financial due diligence when they acquire other companies. But all too often, deal makers simply ignore or underestimate the significance of people issues in mergers and acquisitions. The consequences are severe. Most obviously, there's a high degree of talent loss after a deal's announcement. To make matters worse, differences in decision-making styles lead to infighting; integration stalls; and productivity declines. The good news is that human due diligence can help companies avoid these problems. Done early enough, it helps acquirers decide whether to embrace or kill a deal and determine the price they are willing to pay. It also lays the groundwork for smooth integration. When acquirers have done their homework, they can uncover capability gaps, points of friction, and differences in decision making. Even more important, they can make the critical "people" decisions-who stays, who goes, who runs the combined business, what to do with the rank and file-at the time the deal is announced or shortly thereafter. Making such decisions within the first 30 days is critical to the success of a deal. Hostile situations clearly make things more difficult, but companies can and must still do a certain amount of human due diligence to reduce the inevitable fallout from the acquisition process and smooth the integration. This article details the steps involved in conducting human due diligence. The approach is structured around answering five basic questions: Who is the cultural acquirer? What kind of organization do you want? Will the two cultures mesh? Who are the people you most want to retain? And how will rank-and-file employees react to the deal? Unless an acquiring company has answered these questions to its satisfaction, the acquisition it is making will be very likely to end badly.

  7. H II REGIONS: WITNESSES TO MASSIVE STAR FORMATION

    SciTech Connect

    Peters, Thomas; Banerjee, Robi; Klessen, Ralf S.; Low, Mordecai-Mark Mac; Galvan-Madrid, Roberto; Keto, Eric R.

    2010-03-10

    We describe the first three-dimensional simulation of the gravitational collapse of a massive, rotating molecular cloud that includes heating by both non-ionizing and ionizing radiation. These models were performed with the FLASH code, incorporating a hybrid, long characteristic, ray-tracing technique. We find that as the first protostars gain sufficient mass to ionize the accretion flow, their H II regions are initially gravitationally trapped, but soon begin to rapidly fluctuate between trapped and extended states, in agreement with observations. Over time, the same ultracompact H II region can expand anisotropically, contract again, and take on any of the observed morphological classes. In their extended phases, expanding H II regions drive bipolar neutral outflows characteristic of high-mass star formation. The total lifetime of H II regions is given by the global accretion timescale, rather than their short internal sound-crossing time. This explains the observed number statistics. The pressure of the hot, ionized gas does not terminate accretion. Instead, the final stellar mass is set by fragmentation-induced starvation. Local gravitational instabilities in the accretion flow lead to the build-up of a small cluster of stars, all with relatively high masses due to heating from accretion radiation. These companions subsequently compete with the initial high-mass star for the same common gas reservoir and limit its mass growth. This is in contrast to the classical competitive accretion model, where the massive stars are never hindered in growth by the low-mass stars in the cluster. Our findings show that the most significant differences between the formation of low-mass and high-mass stars are all explained as the result of rapid accretion within a dense, gravitationally unstable, ionized flow.

  8. H II Regions: Witnesses to Massive Star Formation

    NASA Astrophysics Data System (ADS)

    Peters, Thomas; Banerjee, Robi; Klessen, Ralf S.; Mac Low, Mordecai-Mark; Galván-Madrid, Roberto; Keto, Eric R.

    2010-03-01

    We describe the first three-dimensional simulation of the gravitational collapse of a massive, rotating molecular cloud that includes heating by both non-ionizing and ionizing radiation. These models were performed with the FLASH code, incorporating a hybrid, long characteristic, ray-tracing technique. We find that as the first protostars gain sufficient mass to ionize the accretion flow, their H II regions are initially gravitationally trapped, but soon begin to rapidly fluctuate between trapped and extended states, in agreement with observations. Over time, the same ultracompact H II region can expand anisotropically, contract again, and take on any of the observed morphological classes. In their extended phases, expanding H II regions drive bipolar neutral outflows characteristic of high-mass star formation. The total lifetime of H II regions is given by the global accretion timescale, rather than their short internal sound-crossing time. This explains the observed number statistics. The pressure of the hot, ionized gas does not terminate accretion. Instead, the final stellar mass is set by fragmentation-induced starvation. Local gravitational instabilities in the accretion flow lead to the build-up of a small cluster of stars, all with relatively high masses due to heating from accretion radiation. These companions subsequently compete with the initial high-mass star for the same common gas reservoir and limit its mass growth. This is in contrast to the classical competitive accretion model, where the massive stars are never hindered in growth by the low-mass stars in the cluster. Our findings show that the most significant differences between the formation of low-mass and high-mass stars are all explained as the result of rapid accretion within a dense, gravitationally unstable, ionized flow.

  9. Mid-Infrared Spectroscopy of the Most Massive Stars

    NASA Astrophysics Data System (ADS)

    Figer, Donald; Najarro, Paco; Stolovy, Susan

    2004-09-01

    The most massive star that can form is presently defined by observations of a class of very rare stars having inferred initial masses of ~200 solar masses. There are only a few such stars in the Galaxy, including the Pistol Star, FMM362, and LBV 1806-20, the first two being located near the Galactic center, and third located in the disk near W31. Each has only recently been identified as so massive within the past 10 years through the analysis of infrared observations, but they are otherwise too faint, due to extinction, to observe at shorter wavelengths. These stars appear to be very luminous (L>10^6.3 solar luminosities), "blue" (T>10000 K), and variable (delta K~1 mag.), and the Pistol Star has ejected 10 solar masses of material in the past 10000 years. In addition, these stars have near-infrared spectra similar to those of prototypical Luminous Blue Variables, i.e. Eta Car and AG Car. Given their apparent violation of the Humphries-Davidson limit, they are presumably in a short-lived phase of stellar evolution that is often associated with rapid mass-loss through episodic eruptions of their outer atmospheres. We propose to determine the physical properties of these stars and the velocity and ionization structure in their winds by using spectra obtained with the high resolution modes of the Infrared Spectrograph (IRS) on the Spitzer Space Telescope. The 10 to 40 micron wavelength region is ideally suited for accessing a variety of lines from transitions of hydrogen, helium, iron, silicon, sulfur, among others; indeed, through our models, we predict that sufficiently sensitive spectra will yield over 300 spectral lines. In addition, we predict that the mid-infrared continuum will be dominated by free-free emission generated in the thick winds associated with these stars, an effect that should be clearly detectable in the spectra.

  10. Geochemistry of a naturally occurring massive marine gas hydrate

    USGS Publications Warehouse

    Kvenvolden, K.A.; Claypool, G.E.; Threlkeld, C.N.; Dendy, Sloan E.

    1984-01-01

    During Deep Sea Drilling Project (DSDP) Leg 84 a core 1 m long and 6 cm in diameter of massive gas hydrate was unexpectedly recovered at Site 570 in upper slope sediment of the Middle America Trench offshore of Guatemala. This core contained only 5-7% sediment, the remainder being the solid hydrate composed of gas and water. Samples of the gas hydrate were decomposed under controlled conditions in a closed container maintained at 4??C. Gas pressure increased and asymptotically approached the equilibrium decomposition pressure for an ideal methane hydrate, CH4.5-3/4H2O, of 3930 kPa and approached to this pressure after each time gas was released, until the gas hydrate was completely decomposed. The gas evolved during hydrate decomposition was 99.4% methane, ???0.2% ethane, and ???0.4% CO2. Hydrocarbons from propane to heptane were also present, but in concentrations of less than 100 p.p.m. The carbon-isotopic composition of methane was -41 to -44 permil(( 0 00), relative to PDB standard. The observed volumetric methane/water ratio was 64 or 67, which indicates that before it was stored and analyzed, the gas hydrate probably had lost methane. The sample material used in the experiments was likely a mixture of methane hydrate and water ice. Formation of this massive gas hydrate probably involved the following processes: (i) upward migration of gas and its accumulation in a zone where conditions favored the growth of gas hydrates, (ii) continued, unusually rapid biological generation of methane, and (iii) release of gas from water solution as pressure decreased due to sea level lowering and tectonic uplift. ?? 1984.

  11. Salvage intraosseous thrombolysis and extracorporeal membrane oxygenation for massive pulmonary embolism

    PubMed Central

    Northey, Luke Cameron; Shiraev, Timothy; Omari, Abdullah

    2015-01-01

    Intraosseous access is an alternative route of pharmacotherapy during cardiopulmonary resuscitation. Extracorporeal membrane oxygenation (ECMO) provides cardiac and respiratory support when conventional therapies fail. This case reports the use of intraosseous thrombolysis and ECMO in a patient with acute massive pulmonary embolism (PE). A 34-year-old female presented to the emergency department with sudden onset severe shortness of breath. Due to difficulty establishing intravenous access, an intraosseous needle was inserted into the left tibia. Echocardiography identified severe right ventricular dilatation with global systolic impairment and failure, indicative of PE. Due to the patient's hemodynamic compromise a recombinant tissue plasminogen activator (Alteplase) bolus was administered through the intraosseous route. After transfer to the intensive care unit, venous-arterial ECMO was initiated as further therapy. The patient recovered and was discharged 36 days after admission. This is the first report of combination intraosseous thrombolysis and ECMO as salvage therapy for massive PE. PMID:25709256

  12. Acute circulatory deficiency due to endocrinal tumoral manipulation: the pinealoblastoma

    PubMed Central

    Heithem, Chemchihik; Issaoui, Ghazi; Khadraoui, Mejdi; Ladib, Mohamed; Naija, Walid; Said, Rachid

    2014-01-01

    We rapport the case of a patient presenting intra-abdominal metastasis of a pinealoblastoma, via a ventriculo-peritoneal shunt, confirmed by an anatomo-pathologic exam. The patient presented an acute hydrocephalus secondary to DVP dysfunction. The surgical manipulation of this metastasis had caused an acute circulatory deficiency due to massive serotonin release. In this case we analyze pineal gland physiology and serotonin effect on different systems. PMID:25422686

  13. Acute circulatory deficiency due to endocrinal tumoral manipulation: the pinealoblastoma.

    PubMed

    Heithem, Chemchihik; Issaoui, Ghazi; Khadraoui, Mejdi; Ladib, Mohamed; Naija, Walid; Said, Rachid

    2014-01-01

    We rapport the case of a patient presenting intra-abdominal metastasis of a pinealoblastoma, via a ventriculo-peritoneal shunt, confirmed by an anatomo-pathologic exam. The patient presented an acute hydrocephalus secondary to DVP dysfunction. The surgical manipulation of this metastasis had caused an acute circulatory deficiency due to massive serotonin release. In this case we analyze pineal gland physiology and serotonin effect on different systems.

  14. Binary interaction dominates the evolution of massive stars.

    PubMed

    Sana, H; de Mink, S E; de Koter, A; Langer, N; Evans, C J; Gieles, M; Gosset, E; Izzard, R G; Le Bouquin, J-B; Schneider, F R N

    2012-07-27

    The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae. PMID:22837522

  15. Proper Motions of Massive Stars in 30 Doradus

    NASA Astrophysics Data System (ADS)

    Lennon, Daniel

    2013-10-01

    We propose an ambitious proper motion survey of massive stars in the 30 Doradus region of the Large Magellanic Cloud using the unique capabilities of HST. We will derive the directions of motion of massive runaway stars, searching in particular for massive stars which have been ejected from the central very massive cluster R136. These data will be combined with radial velocities from the VLT-FLAMES Survey of the Tarantula Nebula and with atmospheric analyses and stellar evolution models to constrain their origins. We will also search for very young isolated massive stars to test models of single-star formation. This work is highly relevant to star formation, cluster dynamics, the origin of field WR stars and GRBs, the creation of very massive stars by runaway mergers, and the possible formation of intermediate-mass black holes.

  16. Binary interaction dominates the evolution of massive stars.

    PubMed

    Sana, H; de Mink, S E; de Koter, A; Langer, N; Evans, C J; Gieles, M; Gosset, E; Izzard, R G; Le Bouquin, J-B; Schneider, F R N

    2012-07-27

    The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.

  17. Ten Billion Years of Growth: Massive Galaxy Evolution from Structures and Dynamics

    NASA Astrophysics Data System (ADS)

    Bezanson, Rachel

    Once thought to be relies of a much earlier epoch, the most massive local galaxies are red and dead ellipticals, with little ongoing star formation or organized rotation. In the last decade, observations of their assumed progenitors have demonstrated that billions of years ago, massive galaxies were more compact and morphologically different, possibly with more disklike structures. The details of this observed evolution can place constraints on the physical processes that have driven massive galaxy evolution through cosmic time. The work presented in this thesis provides observational constraints on the dynamical and structural evolution of massive galaxies since z ~ 1.5 - 2 using a variety of photometric and spectroscopic surveys, including OBEY, SDSS, NMBS, and UDS. First, we find that although overall densities of these galaxies have decreased with time, the central densities of massive galaxies at high and low redshifts, are quite similar. This suggests that massive galaxies grow "inside-out": compact cores form early and then gradually build a more diffuse envelope of stars in their outskirts. Balancing the need for efficient size growth and consistent number densities of progenitor and descendent galaxies, we conclude that minor-merging is the best physical explanation for the observed size evolution. The remainder of this dissertation focuses on the inferred and measured dynamical evolution of massive galaxies since z ~ 2. Using velocity dispersions inferred by galaxy stellar masses and morphologies, we find that the number density of galaxies at a given velocity dispersion, or velocity dispersion function , is quite stable with redshift since z ~ 1.5, with a weak evolution at the low dispersion end due to a growing population of quenched galaxies. The constancy provides evidence in favor of inside-out growth of galaxies and is consistent with theoretical predictions that the central potentials of massive galaxies are set early. We suggest a toy model that

  18. Ghost free massive gravity with singular reference metrics

    NASA Astrophysics Data System (ADS)

    Zhang, Hongsheng; Li, Xin-Zhou

    2016-06-01

    An auxiliary metric (reference metric) is inevitable in massive gravity theory. In the scenario of the gauge/gravity duality, massive gravity with a singular reference metric is used to study momentum dissipation, which describes the electric and heat conductivity for normal conductors. We demonstrate in detail that the de Rham-Gabadadze-Tolley (dRGT) massive gravity with a singular reference metric is ghost free.

  19. Massive stars in the galaxies of the Local Group

    NASA Astrophysics Data System (ADS)

    Massey, Philip

    2013-07-01

    The star-forming galaxies of the Local Group act as our laboratories for testing massive star evolutionary models. In this review, I briefly summarize what we believe we know about massive star evolution, and the connection between OB stars, Luminous Blue Variables, yellow supergiants, red supergiants, and Wolf-Rayet stars. The difficulties and recent successes in identifying these various types of massive stars in the neighboring galaxies of the Local Group will be discussed.

  20. Moments applied in the rotation of massive objects in Shuttle extravehicular activity

    NASA Technical Reports Server (NTRS)

    Cousins, D.; Akin, D. L.

    1989-01-01

    Experimentally derived applied moments are presented for Space Shuttle crew EVA mission rotations of objects more massive than the human body. These levels appear to be small fractions of physiological limits; horizontal and vertical shoulder strength limits greater than 50 Nm have been established for foot-restrained, pressure-suited subjects in simulated weightlessness. The reduced level in operational EVA may be due to unfamiliarity with manual control in true weightlessness.

  1. Light-front description for the theta dependence of meson masses in the massive Schwinger model

    SciTech Connect

    Burkardt, M.; Harada, K.

    1998-05-01

    We present a continuum formulation for {theta} vacua in the massive Schwinger model on the light front, where {theta} enters as a background electric field. The effective coupling of the external field is partially screened due to vacuum polarization processes. For small fermion masses and small {theta}, we calculate the mass of the meson and find agreement with results from bosonization. {copyright} {ital 1998} {ital The American Physical Society}

  2. Stability and Coalescence of Massive Twin Binaries

    NASA Astrophysics Data System (ADS)

    Hwang, J.; Lombardi, J. C., Jr.; Rasio, F. A.; Kalogera, V.

    2015-06-01

    Massive stars are usually found in binaries, and binaries with periods less than 10 days may have a preference for near equal component masses (“twins”). In this paper we investigate the evolution of massive twin binaries all the way to contact and the possibility that these systems can be progenitors of double neutron star binaries. The small orbital separations of observed double neutron star binaries suggest that the progenitor systems underwent a common envelope phase at least once during their evolution. Bethe & Brown proposed that massive binary twins will undergo a common envelope evolution while both components are ascending the red giant branch (RGB) or asymptotic giant branch (AGB) simultaneously, also known as double-core evolution. Using models generated from the stellar evolution code EZ (evolve zero-age main sequence), we determine the range of mass ratios resulting in a contact binary with both components simultaneously ascending the RGB or AGB as a function of the difference in birth times, Δτ. We find that, even for a generous Δτ = 5 Myr, the minimum mass ratio {{q}min }=0.933 for an 8 {{M}⊙ } primary and increases for larger mass primaries. We use a smoothed particle hydrodynamics code, StarSmasher, to study specifically the evolution of q = 1 common envelope systems as a function of initial component mass, age, and orbital separation. We also consider a q = 0.997 system to test the effect of relaxing the constraint of strictly identical components. We find the dynamical stability limit, the largest orbital separation where the binary becomes dynamically unstable, as a function of the component mass and age. Finally, we calculate the efficiency of ejecting matter during the inspiral phase to extrapolate the properties of the remnant binary from our numerical results, assuming the common envelope is completely ejected. We find that for the nominal core masses, there is a minimum orbital separation for a given component mass such that the

  3. Early experience in endoscopic management of massive intraventricular hemorrhage with literature review

    PubMed Central

    Idris, Zamzuri; Raj, Jason; Abdullah, Jafri Malin

    2014-01-01

    Massive intraventricular hemorrhage (IVH) is nearly always associated with hydrocephalus and is often treated with prolonged external ventricular drainage (EVD); however this procedure can lead to bacterial ventriculitis and meningitis, which can worsen the clinical outcomes. Endoscopic burr hole surgery to remove the hematomas in lateral and third ventricles is an alternative treatment option. We describe the surgical techniques and benefits of endoscopic surgery for acute massive IVH in four patients and discuss the current published literature-related to this condition. Four patients were treated endoscopically for massive IVH. Three patients presented with secondary IVH due to vascular malformation, tumoral bleed and chronic hypertension, while one case presented as massive primary IVH. Endoscopic wash out and removal of hematomas was normally performed together with an endoscopic third ventriculostomy. Recombinant factor VIIa was only administered prior to surgery for IVH secondary to vascular malformation and for cases with postoperative rebleeding which required second endoscopic surgery. Weaning from ventilator and EVD commenced on day 4 postoperatively. All treated patients recovered and did not require further shunt surgery. Good outcomes obtained may be related to early removal of hematomas, creation of new cerebrospinal fluid diversion pathway after thorough wash-out, early weaning from ventilator and EVD. Endoscopic surgery is beneficial in treating poor grade IVH with Graeb score of more than 6. PMID:25685202

  4. Early experience in endoscopic management of massive intraventricular hemorrhage with literature review.

    PubMed

    Idris, Zamzuri; Raj, Jason; Abdullah, Jafri Malin

    2014-01-01

    Massive intraventricular hemorrhage (IVH) is nearly always associated with hydrocephalus and is often treated with prolonged external ventricular drainage (EVD); however this procedure can lead to bacterial ventriculitis and meningitis, which can worsen the clinical outcomes. Endoscopic burr hole surgery to remove the hematomas in lateral and third ventricles is an alternative treatment option. We describe the surgical techniques and benefits of endoscopic surgery for acute massive IVH in four patients and discuss the current published literature-related to this condition. Four patients were treated endoscopically for massive IVH. Three patients presented with secondary IVH due to vascular malformation, tumoral bleed and chronic hypertension, while one case presented as massive primary IVH. Endoscopic wash out and removal of hematomas was normally performed together with an endoscopic third ventriculostomy. Recombinant factor VIIa was only administered prior to surgery for IVH secondary to vascular malformation and for cases with postoperative rebleeding which required second endoscopic surgery. Weaning from ventilator and EVD commenced on day 4 postoperatively. All treated patients recovered and did not require further shunt surgery. Good outcomes obtained may be related to early removal of hematomas, creation of new cerebrospinal fluid diversion pathway after thorough wash-out, early weaning from ventilator and EVD. Endoscopic surgery is beneficial in treating poor grade IVH with Graeb score of more than 6. PMID:25685202

  5. Massive black hole and gas dynamics in galaxy nuclei mergers - I. Numerical implementation

    NASA Astrophysics Data System (ADS)

    Lupi, Alessandro; Haardt, Francesco; Dotti, Massimo

    2015-01-01

    Numerical effects are known to plague adaptive mesh refinement (AMR) codes when treating massive particles, e.g. representing massive black holes (MBHs). In an evolving background, they can experience strong, spurious perturbations and then follow unphysical orbits. We study by means of numerical simulations the dynamical evolution of a pair MBHs in the rapidly and violently evolving gaseous and stellar background that follows a galaxy major merger. We confirm that spurious numerical effects alter the MBH orbits in AMR simulations, and show that numerical issues are ultimately due to a drop in the spatial resolution during the simulation, drastically reducing the accuracy in the gravitational force computation. We therefore propose a new refinement criterion suited for massive particles, able to solve in a fast and precise way for their orbits in highly dynamical backgrounds. The new refinement criterion we designed enforces the region around each massive particle to remain at the maximum resolution allowed, independently upon the local gas density. Such maximally resolved regions then follow the MBHs along their orbits, and effectively avoids all spurious effects caused by resolution changes. Our suite of high-resolution, AMR hydrodynamic simulations, including different prescriptions for the sub-grid gas physics, shows that the new refinement implementation has the advantage of not altering the physical evolution of the MBHs, accounting for all the non-trivial physical processes taking place in violent dynamical scenarios, such as the final stages of a galaxy major merger.

  6. Connecting the Dots: MUSE Unveils the Destructive Effect of Massive Stars

    NASA Astrophysics Data System (ADS)

    McLeod, A. F.; Ginsburg, A.; Klaassen, P.; Mottram, J.; Ramsay, S.; Testi, L.

    2016-09-01

    Throughout their entire lives, massive stars have a substantial impact on their surroundings, such as via protostellar outflows, stellar winds, ionising radiation and supernovae. Conceptually this is well understood, but the exact role of feedback mechanisms on the global star formation process and the stellar environment, as well as their dependence on the properties of the star-forming regions, are yet to be understood in detail. Observational quantification of the various feedback mechanisms is needed to precisely understand how high mass stars interact with and shape their environment, and which feedback mechanisms dominate under given conditions. We analysed the photo-evaporative effect of ionising radiation from massive stars on their surrounding molecular clouds using MUSE integral field data. This allowed us to determine the mass-loss rate of pillar-like structures (due to photo-evaporation) in different environments, and relate it to the ionising power of nearby massive stars. The resulting correlation is the first observational quantification of the destructive effect of ionising radiation from massive stars.

  7. Cluster of cases of massive hemorrhage associated with anticoagulant detection in race horses.

    PubMed

    Carvallo, Francisco R; Poppenga, Robert; Kinde, Hailu; Diab, Santiago S; Nyaoke, Akinyi C; Hill, Ashley E; Arthur, Rick M; Uzal, Francisco A

    2015-01-01

    Five horses originating from 4 different California race tracks were submitted to the California Animal Health and Food Safety Laboratory for necropsy and diagnostic workup. The 5 horses had a history of sudden collapse and death during exercise. In all of them, massive hemoperitoneum and hemorrhages in other cavities or organs were observed. The liver from these 5 animals and from 27 horses that had been euthanized due to catastrophic leg injuries (controls) were subjected to a rodenticide anticoagulant screen. Traces of brodifacoum, diphacinone, or bromadiolone were detected in the 5 horses with massive bleeding (5/5), and no traces of rodenticides were detected in control horses (0/27). Other frequent causes of massive hemorrhages in horses were ruled out in 4 of the cases; one of the horses had a pelvic fracture. Although only traces of anticoagulants were found in the livers of these horses and the role of these substances in the massive bleeding remains uncertain, it is speculated that exercise-related increases in blood pressure may have reduced the threshold for toxicity of these anticoagulants. PMID:25525145

  8. Distributed Compressive CSIT Estimation and Feedback for FDD Multi-User Massive MIMO Systems

    NASA Astrophysics Data System (ADS)

    Rao, Xiongbin; Lau, Vincent K. N.

    2014-06-01

    To fully utilize the spatial multiplexing gains or array gains of massive MIMO, the channel state information must be obtained at the transmitter side (CSIT). However, conventional CSIT estimation approaches are not suitable for FDD massive MIMO systems because of the overwhelming training and feedback overhead. In this paper, we consider multi-user massive MIMO systems and deploy the compressive sensing (CS) technique to reduce the training as well as the feedback overhead in the CSIT estimation. The multi-user massive MIMO systems exhibits a hidden joint sparsity structure in the user channel matrices due to the shared local scatterers in the physical propagation environment. As such, instead of naively applying the conventional CS to the CSIT estimation, we propose a distributed compressive CSIT estimation scheme so that the compressed measurements are observed at the users locally, while the CSIT recovery is performed at the base station jointly. A joint orthogonal matching pursuit recovery algorithm is proposed to perform the CSIT recovery, with the capability of exploiting the hidden joint sparsity in the user channel matrices. We analyze the obtained CSIT quality in terms of the normalized mean absolute error, and through the closed-form expressions, we obtain simple insights into how the joint channel sparsity can be exploited to improve the CSIT recovery performance.

  9. Massive obesity in a migrant Samoan population.

    PubMed Central

    Pawson, I G; Janes, C

    1981-01-01

    Peoples of the Pacific Islands tend to become overweight when they migrate or are exposed to modernization in situ. Recent evidence suggests that Samoans are particularly susceptible, exhibiting a high prevalence of obesity and hypertension following migration to Hawaii. We report the preliminary results of a survey of height, weight, blood pressure, and fasting plasma glucose (FPG) among an urbanized Samoan community the the San Francisco Bay Area. Although the participants' average height fell between the 25th and 50th percentile of the US population, about one-half our sample exceeded the 95th percentile for weight. The extreme overweight was accompanied by elevated blood pressure and, in females, by elevated FPG. The massive adult weight of migrants from the Pacific Islands carries serious public health implications for areas that support large migrant communities. PMID:7212139

  10. Mirage simulations of the massiv sample

    NASA Astrophysics Data System (ADS)

    Amram, P.; Perret, V.; Epinat, B.; Bournaud, F.; Contini, T.; Divoy, C.; Garilli, B.; Kissler-Patig, M.; Le Fevre, O.; Lopez-Sanjuan, C.; Moultaka, J.; Pairo, L.; Perez-Montero, E.; Queyrel, J.; Tasca, L.; Tresse, L.; Vergani, D.

    2015-02-01

    The MIRAGE sample (Merging & isolated high-redshift AMR galaxies; Perret 2014, PhD dissertation; Perret et al. 2014, AA 562, 1) has been built in order to understand the contribution of the merger processes to the mass assembly in the MASSIV (Mass Assembly Survey with SINFONI in VVDS, Contini et al. 2012, AA 539, 91) sample. It consists of a sample of idealized simulations based on the RAMSES code; the initial conditions were designed to reproduce the physical properties of the most gas-rich young galaxies. The sample is composed of 20 simulations of mergers exploring the initial parameters of mass and orientation of the disks with a spatial resolution reaching 7 parsecs.

  11. A nanofluidic system for massively parallel PCR

    NASA Astrophysics Data System (ADS)

    Brenan, Colin; Morrison, Tom; Roberts, Douglas; Hurley, James

    2008-02-01

    Massively parallel nanofluidic systems are lab-on-a-chip devices where solution phase biochemical and biological analyses are implemented in high density arrays of nanoliter holes micro-machined in a thin platen. Polymer coatings make the interior surfaces of the holes hydrophilic and the exterior surface of the platen hydrophobic for precise and accurate self-metered loading of liquids into each hole without cross-contamination. We have created a "nanoplate" based on this concept, equivalent in performance to standard microtiter plates, having 3072 thirty-three nanoliter holes in a stainless steel platen the dimensions of a microscope slide. We report on the performance of this device for PCR-based single nucleotide polymorphism (SNP) genotyping or quantitative measurement of gene expression by real-time PCR in applications ranging from plant and animal diagnostics, agricultural genetics and human disease research.

  12. Massive Open Online Courses in Public Health

    PubMed Central

    Gooding, Ira; Klaas, Brian; Yager, James D.; Kanchanaraksa, Sukon

    2013-01-01

    Massive open online courses (MOOCs) represent a new and potentially transformative model for providing educational opportunities to learners not enrolled in a formal educational program. The authors describe the experience of developing and offering eight MOOCs on a variety of public health topics. Existing institutional infrastructure and experience with both for-credit online education and open educational resources mitigated the institutional risk and resource requirements. Although learners are able to enroll easily and freely and do so in large numbers, there is considerable variety in the level of participation and engagement among enrollees. As a result, comprehensive and accurate assessment of meaningful learning progress remains a major challenge for evaluating the effectiveness of MOOCs for providing public health education. PMID:24350228

  13. Hamiltonian formalism of minimal massive gravity

    NASA Astrophysics Data System (ADS)

    Mahdavian Yekta, Davood

    2015-09-01

    In this paper, we study the three-dimensional minimal massive gravity (MMG) in the Hamiltonian formalism. At first, we define the canonical gauge generators as building blocks in this formalism and then derive the canonical expressions for the asymptotic conserved charges. The construction of a consistent asymptotic structure of MMG requires introducing suitable boundary conditions. In the second step, we show that the Poisson bracket algebra of the improved canonical gauge generators produces an asymptotic gauge group, which includes two separable versions of the Virasoro algebras. For instance, we study the Banados-Teitelboim-Zanelli (BTZ) black hole as a solution of the MMG field equations, and the conserved charges give the energy and angular momentum of the BTZ black hole. Finally, we compute the black hole entropy from the Cardy formula in the dual conformal field theory and show our result is consistent with the value obtained by using the Smarr formula from the holographic principle.

  14. Instability Considerations for Massive Star Eruptions

    NASA Astrophysics Data System (ADS)

    Guzik, J. A.

    2005-09-01

    We propose a mechanism to explain the observed properties of the giant eruptions of `supernova imposters' such as η Car and P Cyg. This mechanism must be episodic, generate a large amount of energy, and be deep seated, in order to lift about 10 solar masses out of the deep gravitational potential well of these massive evolved stars. We suggest that nonradial gravity mode oscillations capable of existing in the core near the hydrogen-burning shell grow slowly to an amplitude sufficient to cause an episode of mixing of hydrogen-rich material downward into hotter denser layers. This mixing generates a burst of nuclear energy production that is responsible for the observed mass ejection and bolometric magnitude increase.

  15. Formation of massive stars by growing accretion

    NASA Astrophysics Data System (ADS)

    Maeder, Andre

    There are at present three scenarios for the formation of massive star. 1) The classical scenario of constant mass pre-Main Sequence (MS) evolution on the Kelvin-Helmholtz timescale. 2) The coalescence scenario, with merging of intermediate mass protostars. 3) The accretion scenario. The various arguments for and against these scenarios are briefly reviewed. We examine the pre-MS evolution of accreting stars for constant accretion rates and for accretion rates which are growing with the stellar masses. The location of the birthlines in the HRD and the lifetimes support accretion rates growing fastly with the stellar masses. Remarkably the dependence found is similar to that of the mass outflows from UC HII regions observed by Churchwell (1999) and Henning et al. (2000). The accretion scenario also leads to a new concept for the maximum stellar mass.

  16. [An unusual case of massive funicular lipoma].

    PubMed

    Masciovecchio, Stefano; Saldutto, Pietro; Del Rosso, Alessandro; Galatioto, Giuseppe Paradiso; Vicentini, Carlo

    2014-01-01

    Intrascrotal lipomas are benign diseases that originate from adipose tissue inside the scrotal sac or constituting the scrotal wall itself. Paratesticular spermatic cord lipomas are a rare type of intrascrotal lipomas. A 78 years old patient in good health comes to our attention for massive tense-elastic swelling of left hemiscrotum appeared about 3 years ago and slowly increasing. Ultrasound evaluation of the intrascrotal mass showed inhomogeneous images mainly hyperechoic, not infiltrating the ipsilateral testis and scrotal wall. The ultrasonography found a lipomatous lesion with benign characteristics and a surgical excision has been performed. The lipomatous mass removed presented a size equal to 25 cm x 14 cm x 11 cm and a weight of about 490 gr. The microscopic examination of the tissue showed only the presence of mature adipocytes in the absence of cellular atypia, of other cellular types and of vascular abnormalities.

  17. Massive young clusters in the Local Group

    NASA Astrophysics Data System (ADS)

    Maíz Apellániz, Jesús

    We analyze the properties of the Massive Young Clusters in the Local Group, concentrating on the youngest segment of this population and, more specifically, on the two best studied cases: 30 Doradus and NGC 604. 30 Doradus is a Super Star Cluster and will likely evolve to become a Globular Cluster in the future. NGC 604, on the other hand, is a Scaled OB Association that will be torn apart by the tidal effects of its host galaxy, M33. Given their extreme youth, each cluster is surrounded by a Giant H II Region produced by the high ionizing fluxes from O and WR stars. The two Giant H II Regions are found to be rather thin structures located on the surfaces of Giant Molecular Clouds, and their geometry turns out to be not too different from that of classical H II regions such as the Orion or Eagle Nebulae.

  18. Hot, Massive Stars in I Zw 18

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Lindler, D.; Malumuth, E.

    2011-01-01

    I Zw 18 is one of the most primitive blue, compact dwarf galaxies. The ionized gas in I Zw 18 has a low oxygen abundance (O approx.1/30 Osun) and nitrogen abundance (N-1/100 Nsun) (Pequignot 2008). We have obtained a far-UV spectrum of the northwest massive star cluster of I Zw 18 using Hubble's Cosmic Origins Spectrograph (COS). The spectrum is compatible with continuous star-formation over the past approx.10 Myr, and a very low metallicity, log Z/Zsun 1.7, although the stellar surface may be enhanced in carbon. Stellar wind lines are very weak, and the edge velocity of wind lines is very low (approx.250 km/s).

  19. Massive superstring scatterings in the Regge regime

    SciTech Connect

    He Song; Lee, Jen-Chi; Takahashi, Keijiro; Yang Yi

    2011-03-15

    We calculate four classes of high-energy massive string scattering amplitudes of fermionic string theory at arbitrary mass levels in the Regge regime (RR). We show that all four leading order amplitudes in the RR can be expressed in terms of the Kummer function of the second kind. Based on the summation algorithm of a set of extended signed Stirling number identities, we show that all four ratios calculated previously by the method of decoupling of zero-norm states among scattering amplitudes in the Gross regime can be extracted from this Kummer function in the RR. Finally, we conjecture and give evidence that the existence of these four Gross regime ratios in the RR persists to subleading orders in the Regge expansion of all high-energy fermionic string scattering amplitudes.

  20. Massive cortical reorganization in sighted Braille readers.

    PubMed

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-03-15

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills.

  1. Massive cortical reorganization in sighted Braille readers.

    PubMed

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-01-01

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills. PMID:26976813

  2. Time sharing massively parallel machines. Draft

    SciTech Connect

    Gorda, B.; Wolski, R.

    1995-03-01

    As part of the Massively Parallel Computing Initiative (MPCI) at the Lawrence Livermore National Laboratory, the authors have developed a simple, effective and portable time sharing mechanism by scheduling gangs of processes on tightly coupled parallel machines. By time-sharing the resources, the system interleaves production and interactive jobs. Immediate priority is given to interactive use, maintaining good response time. Production jobs are scheduled during idle periods, making use of the otherwise unused resources. In this paper the authors discuss their experience with gang scheduling over the 3 year life-time of the project. In section 2, they motivate the project and discuss some of its details. Section 3.0 describes the general scheduling problem and how gang scheduling addresses it. In section 4.0, they describe the implementation. Section 8.0 presents results culled over the lifetime of the project. They conclude this paper with some observations and possible future directions.

  3. The Massive Star Population in M101

    NASA Astrophysics Data System (ADS)

    Grammer, Skyler H.

    An increasing number of non-terminal giant eruptions are being observed by modern supernova and transient surveys. Very little is known about the origin of these giant eruptions and their progenitors which are presumably very-massive, evolved stars such as luminous blue variables, hypergiants, and supergiants. Motivated by the small number of progenitors positively associated with these giant eruptions, we have begun a survey of the luminous and evolved massive star populations in several nearby galaxies. We aim to identify the likely progenitors of the giant eruptions, study the spatial variations in the stellar populations, and examine the relationship between massive star populations and their environment. The work presented here is focused on stellar populations in the relatively nearby, giant, spiral galaxy M101 from sixteen archival BVI HST/ACS images. We create a catalog of stars in the direction to M101 with photometric errors < 10% for V < 24.5 and 50% completeness down to V ˜ 26.5 even in regions of high stellar crowding. Using color and magnitude criteria we have identified candidate luminous OB type stars and blue supergiants, yellow supergiants, and red supergiants for future observation. We examine their spatial distributions across the face of M101 and find that the ratio of blue to red supergiants decreases by two orders of magnitude over the radial extent. From our catalog, we derive the star formation history (SFH) for the stellar populations in five 2' wide annuli by fitting the color-magnitude diagrams. Binning the SFH into time frames corresponding to populations traced by Halpha, far ultraviolet (FUV), and near ultraviolet (NUV) emission, we show that the fraction of stellar populations young enough to contribute in Halpha is 15% " 35% in the inner regions, compared to less than 5% in the outer regions. This provides a sufficient explanation for the lack of Halpha emission at large radii. We also model the blue to red supergiant ratio in our

  4. Hadronic production of massive lepton pairs

    SciTech Connect

    Berger, E.L.

    1982-12-01

    A review is presented of recent experimental and theoretical progress in studies of the production of massive lepton pairs in hadronic collisions. I begin with the classical Drell-Yan annihilation model and its predictions. Subsequently, I discuss deviations from scaling, the status of the proofs of factorization in the parton model, higher-order terms in the perturbative QCD expansion, the discrepancy between measured and predicted yields (K factor), high-twist terms, soft gluon effects, transverse-momentum distributions, implications for weak vector boson (W/sup + -/ and Z/sup 0/) yields and production properties, nuclear A dependence effects, correlations of the lepton pair with hadrons in the final state, and angular distributions in the lepton-pair rest frame.

  5. Cosmic expansion in extended quasidilaton massive gravity

    NASA Astrophysics Data System (ADS)

    Kahniashvili, Tina; Kar, Arjun; Lavrelashvili, George; Agarwal, Nishant; Heisenberg, Lavinia; Kosowsky, Arthur

    2015-02-01

    Quasidilaton massive gravity offers a physically well-defined gravitational theory with nonzero graviton mass. We present the full set of dynamical equations governing the expansion history of the Universe, valid during radiation domination, matter domination, and a late-time self-accelerating epoch related to the graviton mass. The existence of self-consistent solutions constrains the amplitude of the quasidilaton field and the graviton mass, as well as other model parameters. We point out that the effective mass of gravitational waves can be significantly larger than the graviton mass, opening the possibility that a single theory can explain both the late-time acceleration of cosmic expansion and modifications of structure growth leading to the suppression of large-angle correlations observed in the cosmic microwave background.

  6. Formation and Assembly of Massive Star Clusters

    NASA Astrophysics Data System (ADS)

    McMillan, Stephen

    The formation of stars and star clusters is a major unresolved problem in astrophysics. It is central to modeling stellar populations and understanding galaxy luminosity distributions in cosmological models. Young massive clusters are major components of starburst galaxies, while globular clusters are cornerstones of the cosmic distance scale and represent vital laboratories for studies of stellar dynamics and stellar evolution. Yet how these clusters form and how rapidly and efficiently they expel their natal gas remain unclear, as do the consequences of this gas expulsion for cluster structure and survival. Also unclear is how the properties of low-mass clusters, which form from small-scale instabilities in galactic disks and inform much of our understanding of cluster formation and star-formation efficiency, differ from those of more massive clusters, which probably formed in starburst events driven by fast accretion at high redshift, or colliding gas flows in merging galaxies. Modeling cluster formation requires simulating many simultaneous physical processes, placing stringent demands on both software and hardware. Simulations of galaxies evolving in cosmological contexts usually lack the numerical resolution to simulate star formation in detail. They do not include detailed treatments of important physical effects such as magnetic fields, radiation pressure, ionization, and supernova feedback. Simulations of smaller clusters include these effects, but fall far short of the mass of even single young globular clusters. With major advances in computing power and software, we can now directly address this problem. We propose to model the formation of massive star clusters by integrating the FLASH adaptive mesh refinement magnetohydrodynamics (MHD) code into the Astrophysical Multi-purpose Software Environment (AMUSE) framework, to work with existing stellar-dynamical and stellar evolution modules in AMUSE. All software will be freely distributed on-line, allowing

  7. Energetic Supernovae of Very Massive Primordial Stars

    NASA Astrophysics Data System (ADS)

    Chen, Ke-Jung; Woosley, Stan

    2015-08-01

    Current models of the formation of the first stars in the universe suggest that these stars were very massive, having a typical mass scale of hundreds of solar masses. Some of them would die as pair instability supernovae (PSNe) which might be the biggest explosions of the universe. We present the results from multidimensional numerical studies of PSNe with a new radiation-hydrodynamics code, CASTRO and with realistic nuclear reaction networks. We simulate the fluid instabilities that occur in multiple spatial dimensions and discuss how the resulting mixing affects the explosion, mixing, and nucleosynthesis of these supernovae. Our simulations provide useful predictions for the observational signatures of PSNe, which might soon be examined by the James Webb Space Telescope.

  8. Massive superstring scatterings in the Regge regime

    NASA Astrophysics Data System (ADS)

    He, Song; Lee, Jen-Chi; Takahashi, Keijiro; Yang, Yi

    2011-03-01

    We calculate four classes of high-energy massive string scattering amplitudes of fermionic string theory at arbitrary mass levels in the Regge regime (RR). We show that all four leading order amplitudes in the RR can be expressed in terms of the Kummer function of the second kind. Based on the summation algorithm of a set of extended signed Stirling number identities, we show that all four ratios calculated previously by the method of decoupling of zero-norm states among scattering amplitudes in the Gross regime can be extracted from this Kummer function in the RR. Finally, we conjecture and give evidence that the existence of these four Gross regime ratios in the RR persists to subleading orders in the Regge expansion of all high-energy fermionic string scattering amplitudes.

  9. On the cosmology of massive gravity

    NASA Astrophysics Data System (ADS)

    De Felice, Antonio; Emir Gümrükçüoğlu, A.; Lin, Chunshan; Mukohyama, Shinji

    2013-09-01

    We present a review of cosmological solutions in nonlinear massive gravity, focusing on the stability of perturbations. Although homogeneous and isotropic solutions have been found, these are now known to suffer from either the Higuchi ghost or a new nonlinear ghost instability. We discuss two approaches to alleviate this issue. By relaxing the symmetry of the background by e.g. breaking isotropy in the hidden sector, it is possible to accommodate a stable cosmological solution. Alternatively, extending the theory to allow for new dynamical degrees of freedom can also remove the conditions which lead to the instability. As examples for this case, we study the stability of self-accelerating solutions in the quasi-dilatonic extension and generic cosmological solutions in the varying mass extension. While the quasi-dilaton case turns out to be unstable, the varying mass case allows stable regimes of parameters. Viable self-accelerating solutions in the varying mass theory yet remain to be found.

  10. Massive parallelism in the future of science

    NASA Technical Reports Server (NTRS)

    Denning, Peter J.

    1988-01-01

    Massive parallelism appears in three domains of action of concern to scientists, where it produces collective action that is not possible from any individual agent's behavior. In the domain of data parallelism, computers comprising very large numbers of processing agents, one for each data item in the result will be designed. These agents collectively can solve problems thousands of times faster than current supercomputers. In the domain of distributed parallelism, computations comprising large numbers of resource attached to the world network will be designed. The network will support computations far beyond the power of any one machine. In the domain of people parallelism collaborations among large groups of scientists around the world who participate in projects that endure well past the sojourns of individuals within them will be designed. Computing and telecommunications technology will support the large, long projects that will characterize big science by the turn of the century. Scientists must become masters in these three domains during the coming decade.

  11. The outer haloes of massive, elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Das, Payel; Gerhard, Ortwin; de Lorenzi, Flavio; McNeil, Emily; Churazov, Eugene; Coccato, Lodovico

    2010-11-01

    The outer haloes of massive elliptical galaxies are dark-matter dominated regions where stellar orbits have longer dynamical timescales than the central regions and therefore better preserve their formation history. Dynamical models out to large radii suffer from a degeneracy between mass and orbital structure, as the outer kinematics are unable to resolve higher moments of the line-of-sight velocity distribution. We mitigate this degeneracy for a sample of quiescent, massive, nearby ellipticals by determining their mass distributions independently using a non-parametric method on X-ray observations of the surrounding hot interstellar medium. We then create dynamical models using photometric and kinematic constraints consisting of integral-eld, long-slit and planetary nebulae (PNe) data extending to ~50 kpc. The rst two galaxies of our sample, NGC 5846 and NGC 1399, were found to have very shallow pro jected light distributions with a power law index of ~1.5 and a dark matter content of 70-80% at 50 kpc. Spherical Jeans models of the data show that, in the outer haloes of both galaxies, the pro jected velocity dispersions are almost inde- pendent of the anisotropy and that the PNe prefer the lower end of the range of mass distributions consistent with the X-ray data. Using the N-body code NMAGIC, we cre- ated axisymmetric models of NGC 5846 using the individual PNe radial velocities in a likelihood method and found them to be more constraining than the binned velocity dispersions. Characterising the orbital structure in terms of spherically averaged proles of the velocity dispersions we nd σψ > σr > σθ.

  12. Linear stability of magnetized massive protoplanetary disks

    SciTech Connect

    Lin, Min-Kai

    2014-07-20

    Magnetorotational instability (MRI) and gravitational instability (GI) are the two principle routes to turbulent angular momentum transport in accretion disks. Protoplanetary disks (PPDs) may develop both. This paper aims to reinvigorate interest in the study of magnetized massive PPDs, starting from the basic issue of stability. The local linear stability of a self-gravitating, uniformly magnetized, differentially rotating, three-dimensional stratified disk subject to axisymmetric perturbations is calculated numerically. The formulation includes resistivity. It is found that the reduction in the disk thickness by self-gravity (SG) can decrease MRI growth rates; the MRI becomes global in the vertical direction, and MRI modes with small radial length scales are stabilized. The maximum vertical field strength that permits the MRI in a strongly self-gravitating polytropic disk with polytropic index Γ = 1 is estimated to be B{sub z,max}≃c{sub s0}Ω√(μ{sub 0}/16πG), where c{sub s0} is the midplane sound speed and Ω is the local angular velocity. In massive disks with layered resistivity, the MRI is not well localized to regions where the Elsasser number exceeds unity. For MRI modes with radial length scales on the order of the disk thickness, SG can enhance density perturbations, an effect that becomes significant in the presence of a strong toroidal field, and which depends on the symmetry of the underlying MRI mode. In gravitationally unstable disks where GI and MRI growth rates are comparable, the character of unstable modes can transition smoothly between MRI and GI. Implications for nonlinear simulations are discussed briefly.

  13. The Deuteration Clock for Massive Starless Cores

    NASA Astrophysics Data System (ADS)

    Kong, S.; Tan, J. C.; Caselli, P.; Fontani, F.

    2016-05-01

    To understand massive star formation requires study of its initial conditions. Two massive starless core candidates, C1-N & C1-S, have been detected in IRDC G028.37+00.07 in N2D+(3-2) with ALMA. From their line widths, either the cores are subvirial and are thus young structures on the verge of near free-fall collapse, or they are threaded by ˜1 mG B-fields that help support them in near virial equilibrium and potentially have older ages. We modeled the deuteration rate of N2H+ to constrain collapse rates of the cores. First, to measure their current deuterium fraction, D≡ [N2D+]/[N2H+], we observed multiple transitions of N2H+ and N2D+ with CARMA, SMA, JCMT, NRO 45 m and IRAM 30 m, to complement the ALMA data. For both cores we derived D ˜ 0.3, several orders of magnitude above the cosmic [D]/[H] ratio. We then carried out chemodynamical modeling, exploring how collapse rate relative to free-fall, αff, affects the level of D that is achieved from a given initial condition. To reach the observed D, most models require slow collapse with αff˜0.1, i.e., ˜1/10th of free-fall. This makes it more likely that the cores have been able to reach a near virial equilibrium state and we predict that strong B-fields will eventually be detected. The methods developed here will be useful for measurement of the pre-stellar core mass function.

  14. MASSIVE INFANT STARS ROCK THEIR CRADLE

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Extremely intense radiation from newly born, ultra-bright stars has blown a glowing spherical bubble in the nebula N83B, also known as NGC 1748. A new NASA Hubble Space Telescope image has helped to decipher the complex interplay of gas and radiation of a star-forming region in a nearby galaxy. The image graphically illustrates just how these massive stars sculpt their environment by generating powerful winds that alter the shape of the parent gaseous nebula. These processes are also seen in our Milky Way in regions like the Orion Nebula. The Hubble telescope is famous for its contribution to our knowledge about star formation in very distant galaxies. Although most of the stars in the Universe were born several billions of years ago, when the Universe was young, star formation still continues today. This new Hubble image shows a very compact star-forming region in a small part of one of our neighboring galaxies - the Large Magellanic Cloud. This galaxy lies only 165,000 light-years from our Milky Way and can easily be seen with the naked eye from the Southern Hemisphere. Young, massive, ultra-bright stars are seen here just as they are born and emerge from the shelter of their pre-natal molecular cloud. Catching these hefty stars at their birthplace is not as easy as it may seem. Their high mass means that the young stars evolve very rapidly and are hard to find at this critical stage. Furthermore, they spend a good fraction of their youth hidden from view, shrouded by large quantities of dust in a molecular cloud. The only chance is to observe them just as they start to emerge from their cocoon - and then only with very high-resolution telescopes. Astronomers from France, the U.S., and Germany have used Hubble to study the fascinating interplay between gas, dust, and radiation from the newly born stars in this nebula. Its peculiar and turbulent structure has been revealed for the first time. This high-resolution study has also uncovered several individual stars

  15. Dynamic star formation in the massive DR21 filament

    NASA Astrophysics Data System (ADS)

    Schneider, N.; Csengeri, T.; Bontemps, S.; Motte, F.; Simon, R.; Hennebelle, P.; Federrath, C.; Klessen, R.

    2010-09-01

    Context. 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. In addition, magnetic fields may play a decisive role in the star-formation process since they influence the efficiency of gas infall onto the protostar. Aims: 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. Methods: We use molecular line data from our 13CO 1 to 0, CS 2 to 1, and N2H+ 1 to 0 survey of the Cygnus X region obtained with the FCRAO and high-angular resolution observations in isotopomeric lines of CO, CS, HCO+, N2H+, and H2CO, obtained with the IRAM 30 m telescope, to investigate the distribution of the different phases of molecular gas. Gravitational infall is identified by the presence of inverse P Cygni profiles that are detected in optically thick lines, while the optically thinner isotopomers are found to reach a peak in the self-absorption gap. Results: 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+ and 12CO are observed along and across the whole DR21 filament. By modelling the observed spectra, we obtain a typical infall speed of 0.6 km s-1 and mass accretion rates of the order of a few 10-3 M_⊙ yr-1 for the two main clumps constituting the filament. These massive clumps (4900 and 3300 M_⊙ at densities of around 105 cm-3 within 1 pc diameter) are both gravitationally contracting (with free-fall times much shorter

  16. Massive stars. A chemical signature of first-generation very massive stars.

    PubMed

    Aoki, W; Tominaga, N; Beers, T C; Honda, S; Lee, Y S

    2014-08-22

    Numerical simulations of structure formation in the early universe predict the formation of some fraction of stars with several hundred solar masses. No clear evidence of supernovae from such very massive stars has, however, yet been found in the chemical compositions of Milky Way stars. We report on an analysis of a very metal-poor star SDSS J001820.5-093939.2, which possesses elemental-abundance ratios that differ significantly from any previously known star. This star exhibits low [α-element Fe] ratios and large contrasts between the abundances of odd and even element pairs, such as scandium/titanium and cobalt/nickel. Such features have been predicted by nucleosynthesis models for supernovae of stars more than 140 times as massive as the Sun, suggesting that the mass distribution of first-generation stars might extend to 100 solar masses or larger. PMID:25146286

  17. Massive stars. A chemical signature of first-generation very massive stars.

    PubMed

    Aoki, W; Tominaga, N; Beers, T C; Honda, S; Lee, Y S

    2014-08-22

    Numerical simulations of structure formation in the early universe predict the formation of some fraction of stars with several hundred solar masses. No clear evidence of supernovae from such very massive stars has, however, yet been found in the chemical compositions of Milky Way stars. We report on an analysis of a very metal-poor star SDSS J001820.5-093939.2, which possesses elemental-abundance ratios that differ significantly from any previously known star. This star exhibits low [α-element Fe] ratios and large contrasts between the abundances of odd and even element pairs, such as scandium/titanium and cobalt/nickel. Such features have been predicted by nucleosynthesis models for supernovae of stars more than 140 times as massive as the Sun, suggesting that the mass distribution of first-generation stars might extend to 100 solar masses or larger.

  18. Caecal perforation from TB and the Law of Laplace.

    PubMed

    Khan, Amad N; Khalid, Salema; Chaudhry, Mohammad Naushad; Ho, Cherrie

    2015-05-13

    A 43-year-old man presented to the hospital with haemoptysis. When worked up, his history and examination were highly suggestive of pulmonary tuberculosis (TB). He subsequently developed a massive upper gastrointestinal bleed and underwent an emergency laparotomy, which revealed a massively dilated caecum measuring ∼20 cm in diameter. The caecum had perforated due to acute decompensation of intestinal TB. Though common in developing countries, TB is rare in the UK, especially the intestinal kind. The most striking feature of this case is, however, the size of the caecal distension caused by the tubercular inflammation and subsequent perforation-something unheard of in the literature. This massive caecal distention would be explained by the Law of Laplace. In conclusion, massive distension and caecal perforation are possible consequences of intestinal TB, especially in the 48-72 h immediately after starting anti-tubercular therapy.

  19. The evolution of rotating very massive stars with LMC composition

    NASA Astrophysics Data System (ADS)

    Köhler, K.; Langer, N.; de Koter, A.; de Mink, S. E.; Crowther, P. A.; Evans, C. J.; Gräfener, G.; Sana, H.; Sanyal, D.; Schneider, F. R. N.; Vink, J. S.

    2015-01-01

    Context. With growing evidence for the existence of very massive stars at subsolar metallicity, there is an increased need for corresponding stellar evolution models. Aims: We present a dense model grid with a tailored input chemical composition appropriate for the Large Magellanic Cloud (LMC). Methods: We use a one-dimensional hydrodynamic stellar evolution code, which accounts for rotation, transport of angular momentum by magnetic fields, and stellar wind mass loss to compute our detailed models. We calculate stellar evolution models with initial masses from 70 to 500 M⊙ and with initial surface rotational velocities from 0 to 550 km s-1, covering the core-hydrogen burning phase of evolution. Results: We find our rapid rotators to be strongly influenced by rotationally induced mixing of helium, with quasi-chemically homogeneous evolution occurring for the fastest rotating models. Above 160 M⊙, homogeneous evolution is also established through mass loss, producing pure helium stars at core hydrogen exhaustion independent of the initial rotation rate. Surface nitrogen enrichment is also found for slower rotators, even for stars that lose only a small fraction of their initial mass. For models above ~150 M⊙ at zero age, and for models in the whole considered mass range later on, we find a considerable envelope inflation due to the proximity of these models to their Eddington limit. This leads to a maximum ZAMS surface temperature of ~56 000 K, at ~180 M⊙, and to an evolution of stars in the mass range 50 M⊙...100 M⊙ to the regime of luminous blue variables in the Hertzsprung-Russell diagram with high internal Eddington factors. Inflation also leads to decreasing surface temperatures during the chemically homogeneous evolution of stars above ~180 M⊙. Conclusions: The cool surface temperatures due to the envelope inflation in our models lead to an enhanced mass loss, which prevents stars at LMC metallicity from evolving into pair-instability supernovae

  20. Ionizing feedback from massive stars in massive clusters - II. Disruption of bound clusters by photoionization

    NASA Astrophysics Data System (ADS)

    Dale, J. E.; Ercolano, B.; Bonnell, I. A.

    2012-07-01

    We present a smoothed particle hydrodynamics parameter study of the dynamical effect of photoionization from O-type stars on star-forming clouds of a range of masses and sizes during the time window before supernovae explode. Our model clouds all have the same degree of turbulent support initially, the ratio of turbulent kinetic energy to gravitational potential energy being set to Ekin/|Epot|= 0.7. We allow the clouds to form stars and study the dynamical effects of the ionizing radiation from the massive stars or clusters born within them. We find that dense filamentary structures and accretion flows limit the quantities of gas that can be ionized, particularly in the higher density clusters. More importantly, the higher escape velocities in our more massive (106 M⊙) clouds prevent the H II regions from sweeping up and expelling significant quantities of gas, so that the most massive clouds are largely dynamically unaffected by ionizing feedback. However, feedback has a profound effect on the lower density 104 and 105 M⊙ clouds in our study, creating vast evacuated bubbles and expelling tens of per cent of the neutral gas in the 3-Myr time-scale before the first supernovae are expected to detonate, resulting in clouds highly porous to both photons and supernova ejecta.

  1. Atypical CML with massive splenic infarct: an extremely rare presentation.

    PubMed

    Bandyopadhyay, Dhrubajyoti; Manna, Satyaki; Hajra, Adrija; Bhattacharya, Tanima Das

    2015-01-01

    We report a case of a 47-year-old man who presented with hepatosplenomegaly, anaemia and massive splenic infarct. A series of investigations led us to a diagnosis of atypical chronic myeloid leucaemia, a rare variety of a mixed myelodysplastic/myeloproliferative neoplasm. This is the first case of atypical CML presenting with massive splenic infarction.

  2. Massive vulvar edema in 2 prepartum dairy cows.

    PubMed

    Cheong, Soon Hon; Gilbert, Robert O

    2014-05-01

    Two late gestation Holstein cows about to begin the third lactation developed massive vulvar edema. These were the only affected animals in the herd of 500 milking cows. The vulvar edema spontaneously regressed postpartum for both cows. Massive vulvar swelling is seldom observed in dairy cows in advanced pregnancy and is not described in the literature.

  3. Limiting Accretion onto Massive Stars by Fragmentation-Induced Starvation

    SciTech Connect

    Peters, Thomas; Klessen, Ralf S.; Mac Low, Mordecai-Mark; Banerjee, Robi; /ZAH, Heidelberg

    2010-08-25

    Massive stars influence their surroundings through radiation, winds, and supernova explosions far out of proportion to their small numbers. However, the physical processes that initiate and govern the birth of massive stars remain poorly understood. Two widely discussed models are monolithic collapse of molecular cloud cores and competitive accretion. To learn more about massive star formation, we perform simulations of the collapse of rotating, massive, cloud cores including radiative heating by both non-ionizing and ionizing radiation using the FLASH adaptive mesh refinement code. These simulations show fragmentation from gravitational instability in the enormously dense accretion flows required to build up massive stars. Secondary stars form rapidly in these flows and accrete mass that would have otherwise been consumed by the massive star in the center, in a process that we term fragmentation-induced starvation. This explains why massive stars are usually found as members of high-order stellar systems that themselves belong to large clusters containing stars of all masses. The radiative heating does not prevent fragmentation, but does lead to a higher Jeans mass, resulting in fewer and more massive stars than would form without the heating. This mechanism reproduces the observed relation between the total stellar mass in the cluster and the mass of the largest star. It predicts strong clumping and filamentary structure in the center of collapsing cores, as has recently been observed. We speculate that a similar mechanism will act during primordial star formation.

  4. LIMITING ACCRETION ONTO MASSIVE STARS BY FRAGMENTATION-INDUCED STARVATION

    SciTech Connect

    Peters, Thomas; Klessen, Ralf S.; Banerjee, Robi; Low, Mordecai-Mark Mac

    2010-12-10

    Massive stars influence their surroundings through radiation, winds, and supernova explosions far out of proportion to their small numbers. However, the physical processes that initiate and govern the birth of massive stars remain poorly understood. Two widely discussed models are monolithic collapse of molecular cloud cores and competitive accretion. To learn more about massive star formation, we perform and analyze simulations of the collapse of rotating, massive, cloud cores including radiative heating by both non-ionizing and ionizing radiation using the FLASH adaptive-mesh refinement code. These simulations show fragmentation from gravitational instability in the enormously dense accretion flows required to build up massive stars. Secondary stars form rapidly in these flows and accrete mass that would have otherwise been consumed by the massive star in the center, in a process that we term fragmentation-induced starvation. This explains why massive stars are usually found as members of high-order stellar systems that themselves belong to large clusters containing stars of all masses. The radiative heating does not prevent fragmentation, but does lead to a higher Jeans mass, resulting in fewer and more massive stars than would form without the heating. This mechanism reproduces the observed relation between the total stellar mass in the cluster and the mass of the largest star. It predicts strong clumping and filamentary structure in the center of collapsing cores, as has recently been observed. We speculate that a similar mechanism will act during primordial star formation.

  5. Biological tests of lead absorption following a brief massive exposure

    SciTech Connect

    Williams, M.K.

    1984-07-01

    A contractor's man suffered a brief, massive exposure to lead fume by contaminating and then smoking hand-rolled cigarettes. His blood lead concentration rose very rapidly to very high levels, but zinc erythrocyte protoporphyrin, urinary lead, and urinary coproporphyrin did not. It is possible that only the blood lead concentration is of value in detecting brief massive exposure.

  6. [Spontaneous massive retroperitoneal hemorrhage from an adrenal gland cyst].

    PubMed

    Colović, R; Havelka, M; Ostojić, S; Kovacević, N; Lotina, S; Barisić, G; Colić, M

    Adrenal cyst are rare disease. Bleeding, particularly massive, from these cysts is even rarer. The cyst causing spontaneous massive retroperitoneal bleeding in a 17 year old girl is presented. Adrenalectomy was successfully carried out. The patient stayed symptom free so far.

  7. Massive Transfusion Protocol: a local two years' experience.

    PubMed

    Tonglet, M; Minon, J M; Pitance, F; Degesves, S

    2015-01-01

    Evidence supporting the implementation of a Massive Transfusion Protocol (MTP) and its effect on patients' outcome is still limited. However, we implemented in June 2013 a local MTP for trauma and nontrauma massively bleeding patients. Twenty months later, we propose here a short presentation of our MTP population and a critical analysis of the actual data supporting MTP implementation.

  8. Adult granulosa cell tumor presenting with massive ascites, elevated CA-125 level, and low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography

    PubMed Central

    Tak, Ji Young; Park, Ji Y.; Lee, Seung Jeong; Lee, Yoon Hee; Hong, Dae Gy

    2015-01-01

    Adult granulosa cell tumors (AGCTs) presenting with massive ascites and elevated serum CA-125 levels have rarely been described in the literature. An ovarian mass, massive ascites, and elevated serum CA-125 levels in postmenopausal women generally suggest a malignant ovarian tumor, particularly advanced epithelial ovarian cancer. AGCT has low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography due to its low metabolic activity. In the present report, we describe a case of an AGCT with massive ascites, elevated serum CA-125 level, and low 18F-fluorodeoxyglucose uptake on positron emission tomography/computed tomography. PMID:26430671

  9. Analysis of Massively Separated Flows of Aircraft Using Detached Eddy Simulation

    NASA Astrophysics Data System (ADS)

    Morton, Scott

    2002-08-01

    An important class of turbulent flows of aerodynamic interest are those characterized by massive separation, e.g., the flow around an aircraft at high angle of attack. Numerical simulation is an important tool for analysis, though traditional models used in the solution of the Reynolds-averaged Navier-Stokes (RANS) equations appear unable to accurately account for the time-dependent and three-dimensional motions governing flows with massive separation. Large-eddy simulation (LES) is able to resolve these unsteady three-dimensional motions, yet is cost prohibitive for high Reynolds number wall-bounded flows due to the need to resolve the small scale motions in the boundary layer. Spalart et. al. proposed a hybrid technique, Detached-Eddy Simulation (DES), which takes advantage of the often adequate performance of RANS turbulence models in the "thin," typically attached regions of the flow. In the separated regions of the flow the technique becomes a Large Eddy Simulation, directly resolving the time-dependent and unsteady features that dominate regions of massive separation. The current work applies DES to a 70 degree sweep delta wing at 27 degrees angle of attack, a geometrically simple yet challenging flowfield that exhibits the unsteady three-dimensional massively separated phenomena of vortex breakdown. After detailed examination of this basic flowfield, the method is demonstrated on three full aircraft of interest characterized by massive separation, the F-16 at 45 degrees angle of attack, the F-15 at 65 degree angle of attack (with comparison to flight test), and the C-130 in a parachute drop condition at near stall speed with cargo doors open.

  10. Gas and dust hydrodynamical simulations of massive lopsided transition discs - I. Gas distribution

    NASA Astrophysics Data System (ADS)

    Zhu, Zhaohuan; Baruteau, Clément

    2016-06-01

    Motivated by lopsided structures observed in some massive transition discs, we have carried out 2D numerical simulations to study vortex structure in massive discs, including the effects of disc self-gravity and the indirect force which is due to the displacement of the central star from the barycentre of the system by the lopsided structure. When only the indirect force is included, we confirm the finding by Mittal & Chiang that the vortex becomes stronger and can be more than two pressure scale heights wide, as long as the disc-to-star mass ratio is ≳1 per cent. Such wide vortices can excite strong density waves in the disc and therefore migrate inwards rapidly. However, when disc self-gravity is also considered in simulations, self-gravity plays a more prominent role on the vortex structure. We confirm that when the disc Toomre Q parameter is smaller than π/(2h), where h is the disc's aspect ratio, the vortices are significantly weakened and their inward migration slows down dramatically. Most importantly, when the disc is massive enough (e.g. Q ˜ 3), we find that the lopsided gas structure orbits around the star at a speed significantly slower than the local Keplerian speed. This sub-Keplerian pattern speed can lead to the concentration of dust particles at a radius beyond the lopsided gas structure (as shown in Paper II). Overall, disc self-gravity regulates the vortex structure in massive discs and the radial shift between the gas and dust distributions in vortices within massive discs may be probed by future observations.

  11. Parrotfish predation on massive Porites on the Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Bonaldo, R. M.; Bellwood, D. R.

    2011-03-01

    Parrotfish grazing scars on coral colonies were quantified across four reef zones at Lizard Island, Northern Great Barrier Reef (GBR). The abundance of parrotfish grazing scars was highest on reef flat and crest, with massive Porites spp . colonies having more parrotfish grazing scars than all other coral species combined. Massive Porites was the only coral type positively selected for grazing by parrotfishes in all four reef zones. The density of parrotfish grazing scars on massive Porites spp., and the rate of new scar formation, was highest on the reef crest and flat, reflecting the lower massive Porites cover and higher parrotfish abundance in these habitats. Overall, it appears that parrotfish predation pressure on corals could affect the abundance of preferred coral species, especially massive Porites spp , across the reef gradient. Parrotfish predation on corals may have a more important role on the GBR reefs than previously thought.

  12. Massive gravitons as dark matter and gravitational waves

    NASA Astrophysics Data System (ADS)

    Aoki, Katsuki; Mukohyama, Shinji

    2016-07-01

    We consider the possibility that the massive graviton is a viable candidate for dark matter in the context of bimetric gravity. We first derive the energy-momentum tensor of the massive graviton and show that it indeed behaves as that of dark matter fluid. We then discuss a production mechanism and the present abundance of massive gravitons as dark matter. Since the metric to which ordinary matter fields couple is a linear combination of the two mass eigenstates of bigravity, production of massive gravitons, i.e., the dark matter particles, is inevitably accompanied by generation of massless gravitons, i.e., the gravitational waves. Therefore, in this scenario some information about dark matter in our Universe is encoded in gravitational waves. For instance, if LIGO detects gravitational waves generated by the preheating after inflation, then the massive graviton with the mass of ˜0.01 GeV is a candidate for dark matter.

  13. Evolutionary Connections Between RSGs and Other Massive Stars

    NASA Astrophysics Data System (ADS)

    Smith, Nathan

    2015-08-01

    Red supergiants are an important mass-loss phase near the end of a massive star's life, but there are many other evolved mass-losing stars that populate the HR Diagram, and not all massive stars will pass through a red supergiant phase. This talk will provide an overview of other types of massive stars and how they relate to red supergiants. Mass loss by red supergiant winds will be weighed against the mass loss of other massive stars in terms of their contribution to pre-supernova evolution, focussing on trends with initial mass and metallicity. Moreover, some other evolved massive stars have already been RSG or will be in the future, and circumstellar material is an important clue in this regard. Last, the diversity of different supernova explosions, their circumstellar material, and statistics of SN types provide important constraints on the role of RSGs in the latest phases of evolution and mass loss.

  14. First Circumstellar Disk around a Massive Star

    NASA Astrophysics Data System (ADS)

    1998-06-01

    Observations with an infrared-sensitive instrument at the ESO 3.6-m telescope at La Silla have for the first time shown the presence of a disk around a hot and massive star, known as G339.88-1.26 . Until now, disks have only been found around less massive stars. Planets are formed in such disks. The new discovery may thus have important implications for our understanding of the formation of planetary systems around stars. TIMMI observations Observations at mid-infrared wavelengths were carried out in July 1997 by Bringfried Stecklum (Landessternwarte Thüringen, Tautenburg, Germany) and Hans-Ulrich Käufl (ESO), using the TIMMI instrument at the ESO 3.6-m telescope. Additional measurements were carried out in March 1998. TIMMI ( T hermal I nfrared M ulti M ode I nstrument) is a general-purpose camera spectrometer operating at a wavelength of 10 µm. To reach sufficient sensitivity, the camera must be cooled to approx. -260 o C, i.e. a few degrees above the absolute minimum, by use of liquid Helium. Astronomical objects whose temperatures are between -120 o C and 300 o C radiate most of their energy at this wavelength. In addition, dust and haze that are absolutely impenetrable for light visible to the human eye, are often found to be nearly transparent at this wavelength. This is why fire-fighters now use similar equipment to look through smoke. G339.88-1.26: A very special object ESO PR Photo 22a/98 ESO PR Photo 22a/98 [JPEG, 800k] This image is a true-color composite of near-infrared observations of the sky region around the radio source G339.88-1.26 with the ESO/MPI 2.2-m telescope at La Silla. In this image, the visible colors red, green and blue have been used to represent the infrared filters J, H and K (at 1.25, 1.63 and 2.2 µm wavelength, respectively). No object is visible at the position of the radio source, even at these near-infrared wavelengths. A dark band of absorbing dust is clearly visible, exactly at the position of the object (indicated by an

  15. Evolution and fate of very massive stars

    NASA Astrophysics Data System (ADS)

    Yusof, Norhasliza; Hirschi, Raphael; Meynet, Georges; Crowther, Paul A.; Ekström, Sylvia; Frischknecht, Urs; Georgy, Cyril; Abu Kassim, Hasan; Schnurr, Olivier

    2013-08-01

    There is observational evidence that supports the existence of very massive stars (VMS) in the local universe. First, VMS (Mini ≲ 320 M⊙) have been observed in the Large Magellanic Clouds (LMC). Secondly, there are observed supernovae (SNe) that bear the characteristics of pair creation supernovae (PCSNe, also referred to as pair instability SN) which have VMS as progenitors. The most promising candidate to date is SN 2007bi. In order to investigate the evolution and fate of nearby VMS, we calculated a new grid of models for such objects, for solar, LMC and Small Magellanic Clouds (SMC) metallicities, which covers the initial mass range from 120 to 500 M⊙. Both rotating and non-rotating models were calculated using the GENEVA stellar evolution code and evolved until at least the end of helium burning and for most models until oxygen burning. Since VMS have very large convective cores during the main-sequence phase, their evolution is not so much affected by rotational mixing, but more by mass loss through stellar winds. Their evolution is never far from a homogeneous evolution even without rotational mixing. All the VMS, at all the metallicities studied here, end their life as WC(WO)-type Wolf-Rayet stars. Because of very important mass losses through stellar winds, these stars may have luminosities during the advanced phases of their evolution similar to stars with initial masses between 60 and 120 M⊙. A distinctive feature which may be used to disentangle Wolf-Rayet stars originating from VMS from those originating from lower initial masses would be the enhanced abundances of Ne and Mg at the surface of WC stars. This feature is however not always apparent depending on the history of mass loss. At solar metallicity, none of our models is expected to explode as a PCSN. At the metallicity of the LMC, only stars more massive than 300 M⊙ are expected to explode as PCSNe. At the SMC metallicity, the mass range for the PCSN progenitors is much larger and

  16. Massive glosso-cervical arteriovenous malformation: The rationale for a challenging surgical resection

    PubMed Central

    González-García, Raúl; Moreno-García, Carlos

    2014-01-01

    Massive arterivenous malformations (AVM) in the cervico-facial area are rare but potentially life-threatening. Treatment protocols are not well-established. A 41-year old man presented large painless rubber-like mass within the entire neck, which also extended intraorally through the floor of the mouth, showing a slow growing pattern for 5 years. Angiography diagnosed it as cervicofacial AVM. Treatment approach consisted on the embolization of the right upper thyroid, lingual and facial arteries under intravenous sedation. Three days later, bilateral radical neck dissection and subtotal glossectomy was performed. A musculo-cutaneous pectoralis major pedicled flap was harvested to reconstruct the floor of the mouth. Treatment of massive AVMs in the cervico-facial area is challenging due to the associated disfigurement and frequent recurrence rate due to incomplete resection. Also, massive bleeding may be present despite pre-operative super-selective embolization. A new case is presented with focus on surgical treatment considerations. Key words:Arteriovenous malformation, high-flow vascular malformation, cervical region, tongue, surgical resection PMID:25593675

  17. Effects of simulated natural and massive resuspension on benthic oxygen, nutrient and dissolved inorganic carbon fluxes in Loch Creran, Scotland

    NASA Astrophysics Data System (ADS)

    Almroth-Rosell, Elin; Tengberg, Anders; Andersson, Sara; Apler, Anna; Hall, Per O. J.

    2012-08-01

    The effect of repeated natural resuspension on benthic oxygen consumption and the effect of natural and massive resuspension on oxygen consumption and fluxes of phosphate, silicate, ammonium and dissolved inorganic carbon (DIC) were studied at two stations (S1 and S2) in a Scottish sea loch. Station S11 had organically enriched sediment and station S1 had lower organic content in the sediment. The fluxes were measured in situ using the Göteborg benthic lander. Natural resuspension, simulating resuspension events due to strong wind, waves or currents, and massive resuspension, simulating resuspension due to e.g. trawling or dredging, were created inside the incubation chambers by regulating the stirring of the incubated overlying water or by retracting and shaking the incubated sediment. Natural resuspension showed clear effects on the oxygen consumption at station S11, where it increased with an average of 12.8 (standard error (s.e.) 0.17) and 7.7 (s.e. 0.12) mmol m- 2 d- 1 during the first and second incubations, respectively. At station S1 there was no clear effect of natural resuspension on the oxygen consumption. Massive resuspension increased the oxygen consumption on S1 with an average of 608 (standard deviation (sd) 366) mmol m- 2 d- 1 and on S11 with an average of 2396 (sd 2265) mmol m- 2 d- 1. The fluxes of ammonium, phosphate and silicate were affected by the massive resuspension in 50, 14 and 33% of the chambers, respectively, on station S11. However, in the majority of the cases there were no effects on the nutrient and DIC fluxes of massive resuspension. The absolute concentrations of DIC, ammonium and silicate did however instantly increase with an average of 419 (sd 297), 48 (sd 27) and 6.9 (sd 3.7) μM, respectively, at S11 upon massive resuspension. The concentrations of phosphate decreased instantly with an average of 0.2 (sd 0.1) μM. On station S1 there were effects only on the ammonium and silicate concentrations, which increased with 0.8 (sd

  18. Measuring Massive Black Hole Binaries with LISA

    NASA Technical Reports Server (NTRS)

    Lang, Ryan N.; Hughes, Scott A.; Cornish, Neil J.

    2009-01-01

    The coalescence of two massive black holes produces gravitational waves (GWs) which can be detected by the space-based detector LISA. By measuring these waves, LISA can determine the various parameters which characterize the source. Measurements of the black hole masses and spins will provide information about the growth of black holes and their host galaxies over time. Measurements of a source's sky position and distance may help astronomers identify an electromagnetic counterpart to the GW event. The counterpart's redshift, combined with the GW-measured luminosity distance, can then be used to measure the Hubble constant and the dark energy parameter $w$. Because the potential science output is so high, it is useful to know in advance how well LISA can measure source parameters for a wide range of binaries. We calculate expected parameter estimation errors using the well-known Fisher matrix method. Our waveform model includes the physics of spin precession, as well as subleading harmonics. When these higher-order effects are not included, strong degeneracies between some parameters cause them to be poorly determined by a GW measurement. When precession and subleading harmonics are properly included, the degeneracies are broken, reducing parameter errors by one to several orders of magnitude.

  19. MASSIVE HYBRID PARALLELISM FOR FULLY IMPLICIT MULTIPHYSICS

    SciTech Connect

    Cody J. Permann; David Andrs; John W. Peterson; Derek R. Gaston

    2013-05-01

    As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided.

  20. Progress in the Physics of Massive Neutrinos

    NASA Astrophysics Data System (ADS)

    BARGER, V.; MARFATIA, D.; WHISNANT, K.

    The current status of the physics of massive neutrinos is reviewed with a forward-looking emphasis. The article begins with the general phenomenology of neutrino oscillations in vacuum and matter and documents the experimental evidence for oscillations of solar, reactor, atmospheric and accelerator neutrinos. Both active and sterile oscillation possibilities are considered. The impact of cosmology (BBN, CMB, leptogenesis) and astrophysics (supernovae, highest energy cosmic rays) on neutrino observables and vice versa, is evaluated. The predictions of grand unified, radiative and other models of neutrino mass are discussed. Ways of determining the unknown parameters of three-neutrino oscillations are assessed, taking into account eight-fold degeneracies in parameters that yield the same oscillation probabilities, as well as ways to determine the absolute neutrino mass scale (from beta-decay, neutrinoless double-beta decay, large scale structure and Z-bursts). Critical unknowns at present are the amplitude of νμ→νe oscillations and the hierarchy of the neutrino mass spectrum; the detection of CP violation in the neutrino sector depends on these and on an unknown phase. The estimated neutrino parameter sensitivities at future facilities (reactors, superbeams, neutrino factories) are given. The overall agenda of a future neutrino physics program to construct a bottom-up understanding of the lepton sector is presented.

  1. Speckle Interferometry of Massive and Cluster Stars

    NASA Astrophysics Data System (ADS)

    Mason, Brian; Hartkopf, William I.; Gies, Douglas R.; Henry, Todd J.; Tokovinin, Andrei A.

    2006-02-01

    Conducted on NOAO 4-m telescopes in 1994, the first speckle survey of O stars (Mason et al. 1998) had success far in excess of our expectations. In addition to the frequently cited multiplicity analysis, many of the new systems which were first resolved in this paper are of significant astrophysical importance. Now, some ten years after the original survey, we propose to re-investigate all systems analyzed before (N=195). Improvements in detector technology will allow for the detection of companions missed before as well as systems which may have been closer than the resolution limit in 1994. We will also make a first high-resolution inspection of the additional O stars (N=108) in the recent Galactic O Star Catalog of Maiz- Apellaniz & Walborn (2004). Further, we propose to investigate several additional samples of interesting objects, including 15 accessible Galactic WR stars from the speckle survey of Hartkopf et al. (1999), 16 massive, hot stars with separations which would indicate their applicability for mass determinations (for fully detached O stars masses are presently known for only twelve pairs), and 56 multiple stars for a study of their co- planarity statistics.

  2. Speckle Interferometry of Massive and Cluster Stars

    NASA Astrophysics Data System (ADS)

    Mason, Brian; Hartkopf, William I.; Gies, Douglas R.; Henry, Todd J.; Torres, Guillermo

    2005-08-01

    Conducted on NOAO 4-m telescopes in 1994, the first speckle survey of O stars (Mason et al. 1998) had success far in excess of our expectations. In addition to the frequently cited multiplicity analysis, many of the new systems which were first resolved in this paper are of significant astrophysical importance. To date, this paper has resulted in 86 citations in the refereed literature. Now, some ten years after the original survey, we propose to re-investigate all systems analyzed before (N=98) as well as make a first high-resolution inspection of the additional O stars (N=62) in the recent Galactic O Star Catalog of Maiz-Apellaniz & Walborn (2004). In addition, we propose to investigate several additional samples of interesting objects, including 10 accessible Galactic WR stars from the speckle survey of Hartkopf et al. (1999), 16 massive, hot stars with separations which would indicate their applicability for mass determinations (for fully detached O stars, we have only twelve mass determinations), 92 members of the Hyades and Pleiades clusters to complement RV studies of these clusters, and 197 Hyades & Pleiades stars, reobserved from the 1991 lists (Mason et al. 1993a,b).

  3. MASSIVE BLACK HOLES IN CENTRAL CLUSTER GALAXIES

    SciTech Connect

    Volonteri, Marta; Ciotti, Luca

    2013-05-01

    We explore how the co-evolution of massive black holes (MBHs) and galaxies is affected by environmental effects, addressing in particular MBHs hosted in the central cluster galaxies (we will refer to these galaxies in general as ''CCGs''). Recently, the sample of MBHs in CCGs with dynamically measured masses has increased, and it has been suggested that these MBH masses (M{sub BH}) deviate from the expected correlations with velocity dispersion ({sigma}) and mass of the bulge (M{sub bulge}) of the host galaxy: MBHs in CCGs appear to be ''overmassive''. This discrepancy is more pronounced when considering the M{sub BH}-{sigma} relation than the M{sub BH}-M{sub bulge} one. We show that this behavior stems from a combination of two natural factors: (1) CCGs experience more mergers involving spheroidal galaxies and their MBHs and (2) such mergers are preferentially gas poor. We use a combination of analytical and semi-analytical models to investigate the MBH-galaxy co-evolution in different environments and find that the combination of these two factors is in accordance with the trends observed in current data sets.

  4. Improving massive experiments with threshold blocking.

    PubMed

    Higgins, Michael J; Sävje, Fredrik; Sekhon, Jasjeet S

    2016-07-01

    Inferences from randomized experiments can be improved by blocking: assigning treatment in fixed proportions within groups of similar units. However, the use of the method is limited by the difficulty in deriving these groups. Current blocking methods are restricted to special cases or run in exponential time; are not sensitive to clustering of data points; and are often heuristic, providing an unsatisfactory solution in many common instances. We present an algorithm that implements a widely applicable class of blocking-threshold blocking-that solves these problems. Given a minimum required group size and a distance metric, we study the blocking problem of minimizing the maximum distance between any two units within the same group. We prove this is a nondeterministic polynomial-time hard problem and derive an approximation algorithm that yields a blocking where the maximum distance is guaranteed to be, at most, four times the optimal value. This algorithm runs in O(n log n) time with O(n) space complexity. This makes it, to our knowledge, the first blocking method with an ensured level of performance that works in massive experiments. Whereas many commonly used algorithms form pairs of units, our algorithm constructs the groups flexibly for any chosen minimum size. This facilitates complex experiments with several treatment arms and clustered data. A simulation study demonstrates the efficiency and efficacy of the algorithm; tens of millions of units can be blocked using a desktop computer in a few minutes. PMID:27382151

  5. Dark aspects of massive spinor electrodynamics

    NASA Astrophysics Data System (ADS)

    Kim, Edward J.; Kouwn, Seyen; Oh, Phillial; Park, Chan-Gyung

    2014-07-01

    We investigate the cosmology of massive spinor electrodynamics when torsion is non-vanishing. A non-minimal interaction is introduced between the torsion and the vector field and the coupling constant between them plays an important role in subsequential cosmology. It is shown that the mass of the vector field and torsion conspire to generate dark energy and pressureless dark matter, and for generic values of the coupling constant, the theory effectively provides an interacting model between them with an additional energy density of the form ~ 1/a6. The evolution equations mimic ΛCDM behavior up to 1/a3 term and the additional term represents a deviation from ΛCDM. We show that the deviation is compatible with the observational data, if it is very small. We find that the non-minimal interaction is responsible for generating an effective cosmological constant which is directly proportional to the mass squared of the vector field and the mass of the photon within its current observational limit could be the source of the dark energy.

  6. Improving massive experiments with threshold blocking

    PubMed Central

    Higgins, Michael J.; Sekhon, Jasjeet S.

    2016-01-01

    Inferences from randomized experiments can be improved by blocking: assigning treatment in fixed proportions within groups of similar units. However, the use of the method is limited by the difficulty in deriving these groups. Current blocking methods are restricted to special cases or run in exponential time; are not sensitive to clustering of data points; and are often heuristic, providing an unsatisfactory solution in many common instances. We present an algorithm that implements a widely applicable class of blocking—threshold blocking—that solves these problems. Given a minimum required group size and a distance metric, we study the blocking problem of minimizing the maximum distance between any two units within the same group. We prove this is a nondeterministic polynomial-time hard problem and derive an approximation algorithm that yields a blocking where the maximum distance is guaranteed to be, at most, four times the optimal value. This algorithm runs in O(n log n) time with O(n) space complexity. This makes it, to our knowledge, the first blocking method with an ensured level of performance that works in massive experiments. Whereas many commonly used algorithms form pairs of units, our algorithm constructs the groups flexibly for any chosen minimum size. This facilitates complex experiments with several treatment arms and clustered data. A simulation study demonstrates the efficiency and efficacy of the algorithm; tens of millions of units can be blocked using a desktop computer in a few minutes. PMID:27382151

  7. Lagrangians for massive Dirac chiral superfields

    NASA Astrophysics Data System (ADS)

    Jiménez, Enrique; Vaquera-Araujo, C. A.

    2016-06-01

    A variant for the superspin one-half massive superparticle in 4D, N = 1, based on Dirac superfields, is offered. As opposed to the current known models that use spinor chiral superfields, the propagating fields of the supermultiplet are those of the lowest mass dimensions possible: scalar, Dirac and vector fields. Besides the supersymmetric chiral condition, the Dirac superfields are not further constrained, allowing a very straightforward implementation of the path-integral method. The corresponding superpropagators are presented. In addition, an interaction super Yukawa potential, formed by Dirac and scalar chiral superfields, is given in terms of their component fields. The model is first presented for the case of two superspin one-half superparticles related by the charged conjugation operator, but in order to treat the case of neutral superparticles, the Majorana condition on the Dirac superfields is also studied. We compare our proposal with the known models of spinor superfields for the one-half superparticle and show that it is equivalent to them.

  8. Massive cortical reorganization in sighted Braille readers

    PubMed Central

    Siuda-Krzywicka, Katarzyna; Bola, Łukasz; Paplińska, Małgorzata; Sumera, Ewa; Jednoróg, Katarzyna; Marchewka, Artur; Śliwińska, Magdalena W; Amedi, Amir; Szwed, Marcin

    2016-01-01

    The brain is capable of large-scale reorganization in blindness or after massive injury. Such reorganization crosses the division into separate sensory cortices (visual, somatosensory...). As its result, the visual cortex of the blind becomes active during tactile Braille reading. Although the possibility of such reorganization in the normal, adult brain has been raised, definitive evidence has been lacking. Here, we demonstrate such extensive reorganization in normal, sighted adults who learned Braille while their brain activity was investigated with fMRI and transcranial magnetic stimulation (TMS). Subjects showed enhanced activity for tactile reading in the visual cortex, including the visual word form area (VWFA) that was modulated by their Braille reading speed and strengthened resting-state connectivity between visual and somatosensory cortices. Moreover, TMS disruption of VWFA activity decreased their tactile reading accuracy. Our results indicate that large-scale reorganization is a viable mechanism recruited when learning complex skills. DOI: http://dx.doi.org/10.7554/eLife.10762.001 PMID:26976813

  9. Multiplexed microsatellite recovery using massively parallel sequencing

    USGS Publications Warehouse

    Jennings, T.N.; Knaus, B.J.; Mullins, T.D.; Haig, S.M.; Cronn, R.C.

    2011-01-01

    Conservation and management of natural populations requires accurate and inexpensive genotyping methods. Traditional microsatellite, or simple sequence repeat (SSR), marker analysis remains a popular genotyping method because of the comparatively low cost of marker development, ease of analysis and high power of genotype discrimination. With the availability of massively parallel sequencing (MPS), it is now possible to sequence microsatellite-enriched genomic libraries in multiplex pools. To test this approach, we prepared seven microsatellite-enriched, barcoded genomic libraries from diverse taxa (two conifer trees, five birds) and sequenced these on one lane of the Illumina Genome Analyzer using paired-end 80-bp reads. In this experiment, we screened 6.1 million sequences and identified 356958 unique microreads that contained di- or trinucleotide microsatellites. Examination of four species shows that our conversion rate from raw sequences to polymorphic markers compares favourably to Sanger- and 454-based methods. The advantage of multiplexed MPS is that the staggering capacity of modern microread sequencing is spread across many libraries; this reduces sample preparation and sequencing costs to less than $400 (USD) per species. This price is sufficiently low that microsatellite libraries could be prepared and sequenced for all 1373 organisms listed as 'threatened' and 'endangered' in the United States for under $0.5M (USD).

  10. Intestinal adaptation after massive intestinal resection

    PubMed Central

    Weale, A; Edwards, A; Bailey, M; Lear, P

    2005-01-01

    Patients with short bowel syndrome require long term parenteral nutrition support. However, after massive intestinal resection the intestine undergoes adaptation and nutritional autonomy may be obtained. Given that the complications of parenteral nutrition may be life threatening or result in treatment failure and the need for intestinal transplantation, a more attractive option is to wean patients off nutrition support by optimising the adaptive process. The article examines the evidence that after extensive small bowel resection adaptation occurs in humans and focuses on the factors that influence adaptation and the strategies that have been used to optimise this process. The review is based on an English language Medline search with secondary references obtained from key articles. There is evidence that adaptation occurs in humans. Adaptation is a complex process that results in response to nutrient and non-nutrient stimuli. Successful and reproducible strategies to improve adaptation remain elusive despite an abundance of experimental data. Nevertheless given the low patient survival and quality of life associated with other treatments for irreversible intestinal failure it is imperative that clinical research continues into the optimisation of the adaptation. PMID:15749794

  11. Massive hybrid parallelism for fully implicit multiphysics

    SciTech Connect

    Gaston, D. R.; Permann, C. J.; Andrs, D.; Peterson, J. W.

    2013-07-01

    As hardware advances continue to modify the supercomputing landscape, traditional scientific software development practices will become more outdated, ineffective, and inefficient. The process of rewriting/retooling existing software for new architectures is a Sisyphean task, and results in substantial hours of development time, effort, and money. Software libraries which provide an abstraction of the resources provided by such architectures are therefore essential if the computational engineering and science communities are to continue to flourish in this modern computing environment. The Multiphysics Object Oriented Simulation Environment (MOOSE) framework enables complex multiphysics analysis tools to be built rapidly by scientists, engineers, and domain specialists, while also allowing them to both take advantage of current HPC architectures, and efficiently prepare for future supercomputer designs. MOOSE employs a hybrid shared-memory and distributed-memory parallel model and provides a complete and consistent interface for creating multiphysics analysis tools. In this paper, a brief discussion of the mathematical algorithms underlying the framework and the internal object-oriented hybrid parallel design are given. Representative massively parallel results from several applications areas are presented, and a brief discussion of future areas of research for the framework are provided. (authors)

  12. Fluorescence sensing system for seafloor massive sulfides

    NASA Astrophysics Data System (ADS)

    Yamazaki, T.; Okanishi, D.; Nagano, H.; Nakatani, N.; Arai, R.

    2010-12-01

    Seafloor Massive Sulfides (SMS) including Au, Ag, Cu, Zn, Pb and some rare earth elements exist in exclusive economic zones (EEZ) of Pacific island countries and the ones in Japan’s EEZ are the largest and very much attractive. However, there are many problems to be solved for the development. The most important point is the location of ore dressing. If SMS were dressed in the water, energy and cost of transport would drastically decrease. Therefore, fundamental ore dressing method which is an optical measurement, fluorescence sensing system in water is studied. It seems to be able to apply to exploration and mining. No sun light means that ideal optical measurements are possible under artificial one in deep water. However, quite less studies have been done for the optical measurements because general sensing methods at deep water are sound and supersonic waves. Using a light system, the light attenuation and fluorescence characteristics in water are studied. From this study, it is revealed that fluorescence sensing system is applicable and useful for the development of SMS.

  13. Efficient communication in massively parallel computers

    SciTech Connect

    Cypher, R.E.

    1989-01-01

    A fundamental operation in parallel computation is sorting. Sorting is important not only because it is required by many algorithms, but also because it can be used to implement irregular, pointer-based communication. The author studies two algorithms for sorting in massively parallel computers. First, he examines Shellsort. Shellsort is a sorting algorithm that is based on a sequence of parameters called increments. Shellsort can be used to create a parallel sorting device known as a sorting network. Researchers have suggested that if the correct increment sequence is used, an optimal size sorting network can be obtained. All published increment sequences have been monotonically decreasing. He shows that no monotonically decreasing increment sequence will yield an optimal size sorting network. Second, he presents a sorting algorithm called Cubesort. Cubesort is the fastest known sorting algorithm for a variety of parallel computers aver a wide range of parameters. He also presents a paradigm for developing parallel algorithms that have efficient communication. The paradigm, called the data reduction paradigm, consists of using a divide-and-conquer strategy. Both the division and combination phases of the divide-and-conquer algorithm may require irregular, pointer-based communication between processors. However, the problem is divided so as to limit the amount of data that must be communicated. As a result the communication can be performed efficiently. He presents data reduction algorithms for the image component labeling problem, the closest pair problem and four versions of the parallel prefix problem.

  14. MACHO (MAssive Compact Halo Objects) Data

    DOE Data Explorer

    The primary aim of the MACHO Project is to test the hypothesis that a significant fraction of the dark matter in the halo of the Milky Way is made up of objects like brown dwarfs or planets: these objects have come to be known as MACHOs, for MAssive Compact Halo Objects. The signature of these objects is the occasional amplification of the light from extragalactic stars by the gravitational lens effect. The amplification can be large, but events are extremely rare: it is necessary to monitor photometrically several million stars for a period of years in order to obtain a useful detection rate. For this purpose MACHO has a two channel system that employs eight CCDs, mounted on the 50 inch telescope at Mt. Stromlo. The high data rate (several GBytes per night) is accommodated by custom electronics and on-line data reduction. The Project has taken more than 27,000 images with this system since June 1992. Analysis of a subset of these data has yielded databases containing light curves in two colors for 8 million stars in the LMC and 10 million in the bulge of the Milky Way. A search for microlensing has turned up four candidates toward the Large Magellanic Cloud and 45 toward the Galactic Bulge. The web page for data provides links to MACHO Project data portals and various specialized interfaces for viewing or searching the data. (Specialized Interface)

  15. The Chandra Carina Complex Project: Massive Stars

    NASA Astrophysics Data System (ADS)

    Gagne, Marc; Townsley, L.; Corcoran, M.; Cohen, D.; Dickerson, K.; Oskinova, L.; Naze, Y.; Broos, P.; Chandra Carina Complex Project

    2010-03-01

    The Great Nebula in Carina is a superb site to study the violent massive star formation and feedback that typifies giant HII regions and starburst galaxies. We have combined 20 deep, new Chandra ACIS-I pointings with two existing ACIS-I fields to map over one square degree of the Carina complex. A state-of-the-art source detection algorithm has been used to create a catalog of 14,368 x-ray sources, the great majority with counterparts at near- and mid-infrared wavelengths. Carina contains the largest catalogued population of OB stars within 3 kpc, including many known binaries. In this paper, we report on the 130 x-ray detected OB and Wolf-Rayet Stars in the Carina complex. We use their x-ray spectra and light curves to categorize their x-ray emission. Not surprisingly, we find that the known OB and WolfRayet binaries have hard x-ray spectra and high Lx/Lbol strongly suggesting colling wind shocks. Most of the single OB stars have generally lower shock temperatures and lower Lx/Lbol, suggesting wind shocks embedded in the wind. About a dozen of the apparently single OB stars have harder x-ray spectra, and some time variability, possibly suggesting magnetically confined wind shocks, or flaring T Tauri companions.

  16. Difficult laryngoscopy caused by massive mandibular tori.

    PubMed

    Takasugi, Yoshihiro; Shiba, Mayuka; Okamoto, Shinji; Hatta, Koji; Koga, Yoshihisa

    2009-01-01

    Mandibular tori, defined as bony protuberances located along the lingual aspect of the mandible, are a possible cause of difficult intubation. We describe a case of mandibular tori that resulted in difficult intubation. A 62-year-old woman who had speech problems was diagnosed with mandibular tori, and was scheduled for surgical resection. On physical assessment, the patient had a class II Mallampati view and bilateral mandibular tori. Preoperative computed tomography images demonstrated that the bilateral mandibular tori arose from the lingual aspects of the second incisor to the first molar regions of the mandibular corpus, and occupied the floor of the mouth. In the operating room, anesthesia was induced with remifentanil and propofol. After complete paralysis was achieved, laryngoscopy was attempted several times with Macintosh blades. The massive tori prevented insertion of the tip of the blade into the oropharynx, and neither the epiglottis nor the arytenoids could be visualized, i.e., Cormack and Lehane grade IV. Blind nasotracheal intubation was successful and the surgery proceeded uneventfully. The anesthesiologist should examine any space-occupying lesion of the oral floor and should be vigilant for speech problems in order to detect mandibular tori that might impede intubation. PMID:19444571

  17. Hot Ammonia in the Densest Massive Cores

    NASA Astrophysics Data System (ADS)

    Goddi, CiriacoIVE); Zhang, Qizhou

    2014-07-01

    Hot molecular cores are believed to be the birthplace of high-mass (O-B type) stars. Their formation process is however still a matter of debate, chiefly owing to the lack of observational evidence of accreting O-type young stars. In this context, imaging of optically-thin, highly-excited molecular lines at cm-wavelengths provide the best tool for probing the hottest and densest gas at small radii from O-type forming stars, i.e. in centrifugally-supported disks and/or infalling envelopes, whose innermost regions can be inaccessible even to (sub)mm interferometry because of large optical depth of dust emission. In particular, ammonia is an excellent "thermometer" of dense molecular gas and it can trace excitation up to temperatures of 2000 K by observing its inversion transitions within a relatively narrow frequency range, 20-40 GHz, which are sensitive to gas of different temperatures and densities. I will report initial results from an imaging survey of hot-cores in the Galaxy in the ammonia lines from (6,6) up to (14,14) with the JVLA. Towards NGC7538 IRS1 and W51, the multi-transition data sets enabled us to identify the densest massive hot cores known and to probe kinematics of rotating disks and infalling envelopes around O-type young stars.

  18. Relativistic entanglement of two massive particles

    SciTech Connect

    Friis, Nicolai; Bertlmann, Reinhold A.; Huber, Marcus; Hiesmayr, Beatrix C.

    2010-04-15

    We describe the spin and momentum degrees of freedom of a system of two massive spin-(1/2) particles as a four-qubit system. Then we explicitly show how the entanglement changes between different partitions of the qubits, when considered by different inertial observers. Although the two particle entanglement corresponding to a partition into Alice's and Bob's subsystems is, as often stated in the literature, invariant under Lorentz boosts, the entanglement with respect to other partitions of the Hilbert space on the other hand, is not. It certainly does depend on the chosen inertial frame and on the initial state considered. The change of entanglement arises, because a Lorentz boost on the momenta of the particles causes a Wigner rotation of the spin, which in certain cases entangles the spin with the momentum states. We systematically investigate the situation for different classes of initial spin states and different partitions of the four-qubit space. Furthermore, we study the behavior of Bell inequalities for different observers and demonstrate how the maximally possible degree of violation, using the Pauli-Lubanski spin observable, can be recovered by any inertial observer.

  19. Collective excitations of massive flavor branes

    NASA Astrophysics Data System (ADS)

    Itsios, Georgios; Jokela, Niko; Ramallo, Alfonso V.

    2016-08-01

    We study the intersections of two sets of D-branes of different dimensionalities. This configuration is dual to a supersymmetric gauge theory with flavor hypermultiplets in the fundamental representation of the gauge group which live on the defect of the unflavored theory determined by the directions common to the two types of branes. One set of branes is dual to the color degrees of freedom, while the other set adds flavor to the system. We work in the quenched approximation, i.e., where the flavor branes are considered as probes, and focus specifically on the case in which the quarks are massive. We study the thermodynamics and the speeds of first and zero sound at zero temperature and non-vanishing chemical potential. We show that the system undergoes a quantum phase transition when the chemical potential approaches its minimal value and we obtain the corresponding non-relativistic critical exponents that characterize its critical behavior. In the case of (2 + 1)-dimensional intersections, we further study alternative quantization and the zero sound of the resulting anyonic fluid. We finally extend these results to non-zero temperature and magnetic field and compute the diffusion constant in the hydrodynamic regime. The numerical results we find match the predictions by the Einstein relation.

  20. Massive stars in their death throes.

    PubMed

    Eldridge, John J

    2008-12-13

    The study of the stars that explode as supernovae used to be a forensic study, working backwards from the remnants of the star. This changed in 1987 when the first progenitor star was identified in pre-explosion images. Currently, there are eight detected progenitors with another 21 non-detections, for which only a limit on the pre-explosion luminosity can be placed. This new avenue of supernova research has led to many interesting conclusions, most importantly that the progenitors of the most common supernovae, type IIP, are red supergiants, as theory has long predicted. However, no progenitors have been detected thus far for the hydrogen-free type Ib/c supernovae, which, given the expected progenitors, is an unlikely result. Also, observations have begun to show evidence that luminous blue variables, which are among the most massive stars, may directly explode as supernovae. These results contradict the current stellar evolution theory. This suggests that we may need to update our understanding.

  1. Population Models for Massive Globular Clusters

    NASA Astrophysics Data System (ADS)

    Lee, Young-Wook; Joo, Seok-Joo; Han, Sang-Il; Na, Chongsam; Lim, Dongwook; Roh, Dong-Goo

    2015-03-01

    Increasing number of massive globular clusters (GCs) in the Milky Way are now turned out to host multiple stellar populations having different heavy element abundances enriched by supernovae. Recent observations have further shown that [CNO/Fe] is also enhanced in metal-rich subpopulations in most of these GCs, including ω Cen and M22 (Marino et al. 2011, 2012). In order to reflect this in our population modeling, we have expanded the parameter space of Y 2 isochrones and horizontal-branch (HB) evolutionary tracks to include the cases of normal and enhanced nitrogen abundances ([N/Fe] = 0.0, 0.8, and 1.6). The observed variations in the total CNO content were reproduced by interpolating these nitrogen enhanced stellar models. Our test simulations with varying N and O abundances show that, once the total CNO sum ([CNO/Fe]) is held constant, both N and O have almost identical effects on the HR diagram (see Fig. 1).

  2. Little Massive Substructure in CMZ Molecular Clouds

    NASA Astrophysics Data System (ADS)

    Kauffmann, J.; Pillai, T.; Zhang, Q.; Menten, K. M.; Goldsmith, P. F.; Lu, X.; Guzman, A. E.

    2016-05-01

    The Central Molecular Zone (CMZ; inner ˜100pc) hosts some of the most dense and massive molecular clouds of the Milky Way. Studying these clouds can potentially lead to a better understanding of the dense clouds seen in the central starburst regions in nearby galaxies or in the early universe. The clouds share an unusual feature: they form stars at an unusually slow rate compared to other Milky Way clouds of similar mass and density. Here we use interferometer data from ALMA and the SMA to show that this reduced star formation rate is a consequence of the cloud density structure: CMZ clouds have unusually flat density slopes. The clouds do, for example, exceed the average density of the Orion A molecular cloud by an order of magnitude on spatial scales ˜5 pc, but the cores of CMZ clouds with ˜0.1 pc radius often have masses and densities lower than what is found in the Orion KL region. This relative absence of highest-density gas probably explains the suppression of star formation. The clouds are relatively turbulent, and ALMA observations of H2CO and SiO indicate that the turbulence is induced by high-velocity shocks. We speculate that these shocks might prevent the formation of high-mass cores.

  3. Dark aspects of massive spinor electrodynamics

    SciTech Connect

    Kim, Edward J.; Kouwn, Seyen; Oh, Phillial; Park, Chan-Gyung E-mail: seyen@ewha.ac.kr E-mail: parkc@jbnu.ac.kr

    2014-07-01

    We investigate the cosmology of massive spinor electrodynamics when torsion is non-vanishing. A non-minimal interaction is introduced between the torsion and the vector field and the coupling constant between them plays an important role in subsequential cosmology. It is shown that the mass of the vector field and torsion conspire to generate dark energy and pressureless dark matter, and for generic values of the coupling constant, the theory effectively provides an interacting model between them with an additional energy density of the form ∼ 1/a{sup 6}. The evolution equations mimic ΛCDM behavior up to 1/a{sup 3} term and the additional term represents a deviation from ΛCDM. We show that the deviation is compatible with the observational data, if it is very small. We find that the non-minimal interaction is responsible for generating an effective cosmological constant which is directly proportional to the mass squared of the vector field and the mass of the photon within its current observational limit could be the source of the dark energy.

  4. Observing Merging Massive Black Hole Binaries with LISA

    NASA Technical Reports Server (NTRS)

    Thorpe, J.; McWillimas, S.; Baker, J.; Arnaud, K.

    2009-01-01

    The Laser Interferometer Space Antenna (LISA) is expected to detect gravitational radiation from the inspiral and merger of massive black hole binaries at high redshifts with large signal-to-noise ratios (SNRs). These high-SNR observations will make it possible to extract physical parameters such as hole masses and spins, luminosity distance, and sky position from the observed waveforms. LISA'S effectiveness as a tool for astrophysics will be influenced by the precision with which these parameters can be measured. In addition, the practicality of coordinated observations with other instruments will be affected by the temporal evolution of parameter errors such as sky position. We present estimates of parameter errors for the special case of non-spinning black holes. Our focus is on the contribution of the late inspiral and merger portions of the waveform, a regime which typically dominates the SNR but has not been extensively studied due to the historic lack of a precise description of the waveform. Advances in numerical relativity have recently made such studies possible. Initial results suggest that the portion of the waveform beyond the Schwarzchild inner-most stable circular orbit can reduce parameter uncertainties by up to a factor of two.

  5. CORE CREATION IN GALAXIES AND HALOS VIA SINKING MASSIVE OBJECTS

    SciTech Connect

    Goerdt, Tobias; Moore, Ben; Stadel, Joachim; Read, J. I.

    2010-12-20

    We perform a detailed investigation into the disruption of central cusps via the transfer of energy from sinking massive objects. Constant density inner regions form at the radius where the enclosed mass approximately matches the mass of the infalling body. We explore parameter space using numerical simulations and give an empirical relation for the size of the resulting core within structures that have different initial cusp slopes. We find that infalling bodies always stall at the edge of these newly formed cores, experiencing no dynamical friction over many dynamical times. As applications, we consider the resulting decrease in the dark matter annihilation flux due to centrally destroyed cusps, and we present a new theory for the formation of close binary nuclei-the 'stalled binary' model. We focus on one particularly interesting binary nucleus system, the dwarf spheroidal galaxy VCC 128 which is dark matter dominated at all radii. We show that its nuclei would rapidly coalesce within a few million years if it has a central dark matter cusp slope steeper than r {sup -1}. However, if its initial dark matter cusp is slightly shallower than a logslope of -0.75 at {approx}0.1% of the virial radius, then the sinking nuclei naturally create a core equal to their observed separation and stall. This is close to the logslope measured in a recent billion particle cold dark matter halo simulation.

  6. Designing Next Generation Massively Multithreaded Architectures for Irregular Applications

    SciTech Connect

    Tumeo, Antonino; Secchi, Simone; Villa, Oreste

    2012-08-31

    Irregular applications, such as data mining or graph-based computations, show unpredictable memory/network access patterns and control structures. Massively multi-threaded architectures with large node count, like the Cray XMT, have been shown to address their requirements better than commodity clusters. In this paper we present the approaches that we are currently pursuing to design future generations of these architectures. First, we introduce the Cray XMT and compare it to other multithreaded architectures. We then propose an evolution of the architecture, integrating multiple cores per node and next generation network interconnect. We advocate the use of hardware support for remote memory reference aggregation to optimize network utilization. For this evaluation we developed a highly parallel, custom simulation infrastructure for multi-threaded systems. Our simulator executes unmodified XMT binaries with very large datasets, capturing effects due to contention and hot-spotting, while predicting execution times with greater than 90% accuracy. We also discuss the FPGA prototyping approach that we are employing to study efficient support for irregular applications in next generation manycore processors.

  7. Gravitational lensing by a rotating massive object in a plasma

    NASA Astrophysics Data System (ADS)

    Morozova, V. S.; Ahmedov, B. J.; Tursunov, A. A.

    2013-08-01

    We study gravitational lensing in the vicinity of a slowly rotating massive object surrounded by a plasma. We have studied two effects: (i) the influence of the frame dragging on the deflection angle of the light ray in the presence of plasma (ii) Faraday rotation of the polarization plane of the light. We derive the expression for the lensing angle in a non-diagonal space-time in the weak field regime in the presence of plasma and discuss it for the spacetime metric of the slowly rotating object. The obtained deflection angle depends on (i) the frequency of the electromagnetic wave, due to the dispersion properties of the plasma; (ii) the gravitational mass M; and (iii) the angular momentum J of the gravitational lens. We studied the influence of rotation of the gravitational lens on the magnification of brightness of the source star in the case of microlensing and have shown that it is negligibly small. For the completeness of our study the effect of the Faraday rotation of the polarization plane is considered.

  8. A DARK SPOT ON A MASSIVE WHITE DWARF

    SciTech Connect

    Kilic, Mukremin; Gianninas, Alexandros; Curd, Brandon; Wisniewski, John P.; Bell, Keaton J.; Winget, D. E.; Winget, K. I.; Brown, Warren R.; Hermes, J. J.; Dufour, Patrick

    2015-12-01

    We present the serendipitous discovery of eclipse-like events around the massive white dwarf SDSS J152934.98+292801.9 (hereafter J1529+2928). We selected J1529+2928 for time-series photometry based on its spectroscopic temperature and surface gravity, which place it near the ZZ Ceti instability strip. Instead of pulsations, we detect photometric dips from this white dwarf every 38 minutes. Follow-up optical spectroscopy observations with Gemini reveal no significant radial velocity variations, ruling out stellar and brown dwarf companions. A disintegrating planet around this white dwarf cannot explain the observed light curves in different filters. Given the short period, the source of the photometric dips must be a dark spot that comes into view every 38 minutes due to the rotation of the white dwarf. Our optical spectroscopy does not show any evidence of Zeeman splitting of the Balmer lines, limiting the magnetic field strength to B < 70 kG. Since up to 15% of white dwarfs display kG magnetic fields, such eclipse-like events should be common around white dwarfs. We discuss the potential implications of this discovery on transient surveys targeting white dwarfs, like the K2 mission and the Large Synoptic Survey Telescope.

  9. SUPERSONIC LINE BROADENING WITHIN YOUNG AND MASSIVE SUPER STAR CLUSTERS

    SciTech Connect

    Tenorio-Tagle, Guillermo; Silich, Sergiy; Wuensch, Richard; Munoz-Tunon, Casiana; Palous, Jan E-mail: richard@wunsch.c E-mail: cmt@ll.iac.e

    2010-01-10

    The origin of supersonic infrared and radio recombination nebular lines often detected in young and massive superstar clusters is discussed. We suggest that these arise from a collection of repressurizing shocks (RSs), acting effectively to re-establish pressure balance within the cluster volume and from the cluster wind which leads to an even broader although much weaker component. The supersonic lines here are shown to occur in clusters that undergo a bimodal hydrodynamic solution, that is within clusters that are above the threshold line in the mechanical luminosity or cluster mass versus the size of the cluster plane. A plethora of RSs is due to frequent and recurrent thermal instabilities that take place within the matter reinserted by stellar winds and supernovae. We show that the maximum speed of the RSs and of the cluster wind are both functions of the temperature reached at the stagnation radius. This temperature depends only on the cluster heating efficiency (eta). Based on our two-dimensional simulations we calculate the line profiles that result from several models and confirm our analytical predictions. From a comparison between the predicted and observed values of the half-width zero intensity of the two line components, we conclude that the thermalization efficiency in young super star clusters above the threshold line must be lower than 20%.

  10. Self-gravitating disc candidates around massive young stars

    NASA Astrophysics Data System (ADS)

    Forgan, D. H.; Ilee, J. D.; Cyganowski, C. J.; Brogan, C. L.; Hunter, T. R.

    2016-11-01

    There have been several recent detections of candidate Keplerian discs around massive young protostars. Given the relatively large disc-to-star mass ratios in these systems, and their young ages, it is worth investigating their propensity to becoming self-gravitating. To this end, we compute self-consistent, semi-analytic models of putative self-gravitating discs for five candidate disc systems. Our aim is not to fit exactly the observations, but to demonstrate that the expected dust continuum emission from marginally unstable self-gravitating discs can be quite weak, due to high optical depth at the mid-plane even at millimetre wavelengths. In the best cases, the models produce `observable' disc masses within a factor of <1.5 of those observed, with mid-plane dust temperatures comparable to measured temperatures from molecular line emission. We find in two cases that a self-gravitating disc model compares well with observations. If these discs are self-gravitating, they satisfy the conditions for disc fragmentation in their outer regions. These systems may hence have as-yet-unresolved low-mass stellar companions, and are thus promising targets for future high angular resolution observations.

  11. Polarization of massive fermions in a vortical fluid

    NASA Astrophysics Data System (ADS)

    Fang, Ren-hong; Pang, Long-gang; Wang, Qun; Wang, Xin-nian

    2016-08-01

    Fermions become polarized in a vortical fluid due to spin-vorticity coupling. Such a polarization can be calculated from the Wigner function in a quantum kinetic approach. By extending previous results for chiral fermions, we derive the Wigner function for massive fermions up to next-to-leading order in spatial gradient expansion. The polarization density of fermions can be calculated from the axial vector component of the Wigner function and is found to be proportional to the local vorticity ω . The polarizations per particle for fermions and antifermions decrease with the chemical potential and increase with energy (mass). Both quantities approach the asymptotic value ℏ ω /4 in the large energy (mass) limit. The polarization per particle for fermions is always smaller than that for antifermions, whose ratio of fermions to antifermions also decreases with the chemical potential. The polarization per particle on the Cooper-Frye freeze-out hypersurface can also be formulated and is consistent with the previous result of Becattini et al.

  12. A case of solitary fibrous tumor in the pelvis presenting massive hemorrhage during surgery.

    PubMed

    Kim, Mi Young; Jeon, Seob; Choi, Seung Do; Nam, Kye Hyun; Sunwoo, Jae Gun; Lee, Ji-Hye

    2015-01-01

    Solitary fibrous tumors (SFTs) are unique soft-tissue tumors of submesothelial origin. These tumors are mainly located in the pleural space but they can be originated within a variety of sites, including the abdomen, the pelvis, the soft tissues and the retroperitoneum. SFTs from all sites are usually benign, and the surgical resection is curative in almost all cases. According to the review of literatures, during the surgical resection, massive hemorrhage could occur due to the hypervascular nature of SFTs. This is a case report on SFT in the pelvis presenting great vessel injury, which resulted in life threatening hemorrhage during the resection of tumor. We wish this paper alerts gynecologists about the risk of massive bleeding during the resection of tumor located at adjacent to great vessels in the pelvis.

  13. Traumatic pseudoaneurysm of the intracavernous ICA presenting with massive epistaxis: imaging diagnosis and endovascular treatment.

    PubMed

    Han, M H; Sung, M W; Chang, K H; Min, Y G; Han, D H; Han, M C

    1994-03-01

    Traumatic pseudoaneurysm of the intracavernous internal carotid artery (ICA) is a very rare cause of epistaxis but is a life-threatening clinical situation when left untreated. The authors have experienced four cases of traumatic pseudoaneurysm involving the intracavernous ICA. Delayed massive epistaxes developed 1 to 8 months after trauma and initial transient epistaxis in all four patients. Three of the cases were successfully managed by the detachable balloon occlusion (DBO) of the ICA along with the aneurysm openings. In one case, a large pseudoaneurysm destroying a large area of the central skull base with peripheral blood clot was demonstrated on computed tomography, magnetic resonance imaging, and angiography; this patient died due to massive epistaxis before the trial of DBO. Imaging findings of pseudoaneurysms involving the intracavernous ICA in the four cases are described, and the role of endovascular treatment is discussed.

  14. A domain decomposition study of massively parallel computing in compressible gas dynamics

    SciTech Connect

    Wong, C.C.; Blottner, F.G.; Payne, J.L.; Soetrisno, M.

    1995-01-01

    The appropriate utilization of massively parallel computers for solving the Navier-Stokes equations is investigated and determined from an engineering perspective. The issues investigated are: (1) Should strip or patch domain decomposition of the spatial mesh be used to reduce computer time? (2) How many computer nodes should be used for a problem with a given sized mesh to reduce computer time? (3) Is the convergence of the Navier-Stokes solution procedure (LU-SGS) adversely influenced by the domain decomposition approach? The results of the paper show that the present Navier-Stokes solution technique has good performance on a massively parallel computer for transient flow problems. For steady-state problems with a large number of mesh cells, the solution procedure will require significant computer time due to an increased number of iterations to achieve a converged solution. There is an optimum number of computer nodes to use for a problem with a given global mesh size.

  15. A semi-analytical model for exploring Galilean satellites formation from a massive disk

    NASA Astrophysics Data System (ADS)

    Miguel, Yamila; Ida, Shigeru

    2016-03-01

    A better knowledge of jovian satellites' origins will bring light on the environment that surrounded Jupiter during its formation and can help us to understand the characteristics of this unique satellite system. We developed a semi-analytical model to investigate Jupiter's regular satellite formation and present the results of our population synthesis calculations. We performed simulations adopting a massive, static, low-viscosity circumplanetary disk model, in agreement with a current study of magnetorotational instability in a circum-planetary disk. We find that the high gas density leads to very rapid migration of satellitesimals due to gas drag and type II migration of satellites in a faster disk-dominated mode. A large concentration of solids, large building blocks and longer type II migration time-scales favor formation and survival of large satellites. However, bodies as massive as Ganymede and those located far away from Jupiter, such as Callisto, are difficult to form with this scenario.

  16. Pigmentation of massive corals as a simple bioindicator for marine water quality.

    PubMed

    Cooper, Timothy F; Fabricius, Katharina E

    2012-01-01

    Photo-acclimatisation by the algal endosymbionts of scleractinian corals to changes in environmental conditions may influence their density and/or the concentration of photosynthetic pigments, and hence coral brightness, on short time-scales. To examine coral pigmentation as a bioindicator of water quality, the brightness of massive corals was quantified using colour charts, concentrations of the pigment chlorophyll a and reflectance spectrometry in the field and with manipulative experiments. Along a water quality gradient, massive Porites became progressively lighter as nutrients decreased and irradiance increased. A laboratory experiment showed that Porites nubbins darkened within 25 days following exposure to reduced water quality. The results of a transplantation experiment of Porites nubbins in a manipulation incorporating multiple depths and zones of water quality confirmed colony brightness as a simple tool to monitor changes in marine water quality, provided effects due to other influences on pigmentation, e.g. seawater temperatures, are taken into consideration.

  17. Development of Microreactor Array Chip-Based Measurement System for Massively Parallel Analysis of Enzymatic Activity

    NASA Astrophysics Data System (ADS)

    Hosoi, Yosuke; Akagi, Takanori; Ichiki, Takanori

    Microarray chip technology such as DNA chips, peptide chips and protein chips is one of the promising approaches for achieving high-throughput screening (HTS) of biomolecule function since it has great advantages in feasibility of automated information processing due to one-to-one indexing between array position and molecular function as well as massively parallel sample analysis as a benefit of down-sizing and large-scale integration. Mostly, however, the function that can be evaluated by such microarray chips is limited to affinity of target molecules. In this paper, we propose a new HTS system of enzymatic activity based on microreactor array chip technology. A prototype of the automated and massively parallel measurement system for fluorometric assay of enzymatic reactions was developed by the combination of microreactor array chips and a highly-sensitive fluorescence microscope. Design strategy of microreactor array chips and an optical measurement platform for the high-throughput enzyme assay are discussed.

  18. "Retired" Planet Hosts: Not So Massive, Maybe Just Portly After Lunch

    NASA Astrophysics Data System (ADS)

    Lloyd, James P.

    2011-10-01

    Studies of the planet abundance as a function of stellar mass have suggested a strong increase in the frequency of planet occurrence around stars more massive than 1.5 M sun, and that such stars are deficit in short-period planets. These planet searches have relied on giant stars for a sample of high mass stars, which are hostile to precision Doppler measurements due to rotation and activity while on the main sequence. This Letter considers the observed vsin i and observationally inferred mass for exoplanet hosting giants with the vsin i of distribution of field stars, which show discrepancies that can be explained by erroneous mass determinations of some exoplanet host stars. By comparison with an expected mass distribution constructed from integrating isochrones, it is shown that the exoplanet hosts are inconsistent with a population of massive stars. These stars are more likely to have originated from a main-sequence population of late F/early G dwarfs with mass 1.0-1.2 M sun, only slightly more massive than the typical FGK dwarfs with Doppler detected planets. The deficit of short-period planets is most likely explained by tidal capture. The planet abundance difference requires either a steeper increase in planet frequency with mass than previously thought or a high rate of false positives due to signals of stellar origin. The measurement of photospheric carbon isotope ratios is suggested as a method to discriminate whether this sample of giant stars is significantly more massive than the population of FGK dwarfs with Doppler detected planets.

  19. Supervised detection of anomalous light curves in massive astronomical catalogs

    SciTech Connect

    Nun, Isadora; Pichara, Karim; Protopapas, Pavlos; Kim, Dae-Won

    2014-09-20

    The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable objects in large astronomical catalogs. With the aim of taking full advantage of all information we have about known objects, our method is based on a supervised algorithm. In particular, we train a random forest classifier using known variability classes of objects and obtain votes for each of the objects in the training set. We then model this voting distribution with a Bayesian network and obtain the joint voting distribution among the training objects. Consequently, an unknown object is considered as an outlier insofar it has a low joint probability. By leaving out one of the classes on the training set, we perform a validity test and show that when the random forest classifier attempts to classify unknown light curves (the class left out), it votes with an unusual distribution among the classes. This rare voting is detected by the Bayesian network and expressed as a low joint probability. Our method is suitable for exploring massive data sets given that the training process is performed offline. We tested our algorithm on 20 million light curves from the MACHO catalog and generated a list of anomalous candidates. After analysis, we divided the candidates into two main classes of outliers: artifacts and intrinsic outliers. Artifacts were principally due to air mass variation, seasonal variation, bad calibration, or instrumental errors and were consequently removed from our outlier list and added to the training set. After retraining, we selected about 4000 objects, which we passed to a post-analysis stage by performing a cross-match with all publicly available catalogs. Within these candidates we identified certain known

  20. The flat density profiles of massive, and relaxed galaxy clusters

    NASA Astrophysics Data System (ADS)

    Del Popolo, A.

    2014-07-01

    The present paper is an extension and continuation of Del Popolo (2012a) which studied the role of baryon physics on clusters of galaxies formation. In the present paper, we studied by means of the SIM introduced in Del Popolo (2009), the total and DM density profiles, and the correlations among different quantities, observed by Newman et al. (2012a,b), in seven massive and relaxed clusters, namely MS2137, A963, A383, A611, A2537, A2667, A2390. As already found in Del Popolo 2012a, the density profiles depend on baryonic fraction, angular momentum, and the angular momentum transferred from baryons to DM through dynamical friction. Similarly to Newman et al. (2012a,b), the total density profile, in the radius range 0.003-0.03r200, has a mean total density profile in agreement with dissipationless simulations. The slope of the DM profiles of all clusters is flatter than -1. The slope, α, has a maximum value (including errors) of α = -0.88 in the case of A2390, and minimum value α = -0.14 for A2537. The baryonic component dominates the mass distribution at radii < 5-10 kpc, while the outer distribution is dark matter dominated. We found an anti-correlation among the slope α, the effective radius, Re, and the BCG mass, and a correlation among the core radius rcore, and Re. Moreover, the mass in 100 kpc (mainly dark matter) is correlated with the mass inside 5 kpc (mainly baryons). The behavior of the total mass density profile, the DM density profile, and the quoted correlations can be understood in a double phase scenario. In the first dissipative phase the proto-BCG forms, and in the second dissipationless phase, dynamical friction between baryonic clumps (collapsing to the center) and the DM halo flattens the inner slope of the density profile. In simple terms, the large scatter in the inner slope from cluster to cluster, and the anti-correlation among the slope, α and Re is due to the fact that in order to have a total mass density profile which is NFW

  1. The flat density profiles of massive, and relaxed galaxy clusters

    SciTech Connect

    Popolo, A. Del

    2014-07-01

    The present paper is an extension and continuation of Del Popolo (2012a) which studied the role of baryon physics on clusters of galaxies formation. In the present paper, we studied by means of the SIM introduced in Del Popolo (2009), the total and DM density profiles, and the correlations among different quantities, observed by Newman et al. (2012a,b), in seven massive and relaxed clusters, namely MS2137, A963, A383, A611, A2537, A2667, A2390. As already found in Del Popolo 2012a, the density profiles depend on baryonic fraction, angular momentum, and the angular momentum transferred from baryons to DM through dynamical friction. Similarly to Newman et al. (2012a,b), the total density profile, in the radius range 0.003–0.03r{sub 200}, has a mean total density profile in agreement with dissipationless simulations. The slope of the DM profiles of all clusters is flatter than -1. The slope, α, has a maximum value (including errors) of α = −0.88 in the case of A2390, and minimum value α = −0.14 for A2537. The baryonic component dominates the mass distribution at radii < 5–10 kpc, while the outer distribution is dark matter dominated. We found an anti-correlation among the slope α, the effective radius, R{sub e}, and the BCG mass, and a correlation among the core radius r{sub core}, and R{sub e}. Moreover, the mass in 100 kpc (mainly dark matter) is correlated with the mass inside 5 kpc (mainly baryons). The behavior of the total mass density profile, the DM density profile, and the quoted correlations can be understood in a double phase scenario. In the first dissipative phase the proto-BCG forms, and in the second dissipationless phase, dynamical friction between baryonic clumps (collapsing to the center) and the DM halo flattens the inner slope of the density profile. In simple terms, the large scatter in the inner slope from cluster to cluster, and the anti-correlation among the slope, α and R{sub e} is due to the fact that in order to have a total

  2. Do you know the extinction in your young massive cluster?

    NASA Astrophysics Data System (ADS)

    De Marchi, Guido; Panagia, Nino; Sabbi, Elena; HTTP Team

    2015-08-01

    Up to ages of a few 100 Myr, massive clusters are still swamped in large amounts of gas and dust from their primordial cocoons. This causes considerable and uneven levels of extinction across the cluster that we must understand and measure if we want to extract any physically meaningful parameters, from basic luminosities and effective temperatures to masses and ages. We have developed a powerful method to unambiguously determine the extinction law and the absolute value of the extinction in a uniform way across a cluster field, using multi-band photometry of red giant stars belonging to the red clump (RC). Since these stars share very similar physical properties, they allow us to derive the absolute extinction in a straightforward and reliable way. In the Magellanic Clouds, with about 20 RC stars arcmin-2 or ~150 objects in a typical HST pointing, we can easily derive a solid and self-consistent absolute extinction curve over the entire wavelength range of the photometry, with no need for spectroscopy.I will show an application of this method to the Hubble Tarantula Treasury Project's observations of the Tarantula nebula, containing the massive R136 cluster. We have measured the absolute extinction towards about 3600 objects and the extinction law in the range 0.3 - 1.6 μm. At optical wavelengths, the extinction curve is almost parallel to that of the diffuse Galactic interstellar medium (ISM), but the value of RV = AV/E(B-V) = 4.5 ± 0.2 that we measure indicates that in the optical there is an extra grey component due to a larger fraction of large grains. Using the RV = 3.1 value typical of the diffuse Galactic ISM would severely underestimate the luminosities and masses and overestimate the ages of the stars in the cluster. At wavelengths longer than ~ 1 μm, the contribution of this additional component tapers off as λ-1.5, like in the Milky Way, suggesting that the nature of the grains is otherwise similar to those in our Galaxy, but with a ~ 2 times higher

  3. Optimization of massive countermeasure design in complex rockfall settings

    NASA Astrophysics Data System (ADS)

    Agliardi, Federico; Crosta, Giovanni B.

    2015-04-01

    Rockfall protection is a major need in areas impended by subvertical rockwalls with complex 3D morphology and little or no talus to provide natural rockfall attenuation. The design of massive embankments, usually required to ensure such protection, is particularly difficult in complex rockfall settings, due to: widespread occurrence of rockfall sources; difficult characterization of size distribution and location of unstable volumes; variability of failure mechanisms; spatial scattering of rockfall trajectories; high expected kinetic energies. Moreover, rockwalls in complex lithological and structural settings are often prone to mass falls related to rock mass sector collapses. All these issues may hamper a safe application of classic embankment analysis approaches, using empirical rules or 2D-based height/energy statistics, and point to the need of integrated analyses of rock slope instability and rockfall runout in 3D. We explore the potential of combining advanced rock mass characterisation techniques and 3D rockfall modelling to support challenging countermeasure design at a site near Lecco (Southern Alps, Italy). Here subvertical cliffs up to 600 m high impend on a narrow (< 150 m) strip of flat land along the Como Lake shore. Rock is thickly bedded limestone (Dolomia Principale Fm) involved in a ENE-trending, S-verging kilometre-scale anticline fold. The spatial variability of bedding attitude and fracture intensity is strongly controlled by the geological structure, with individual block sizes varying in the range 0.2-15 m3. This results in spatially variable rockfall susceptibility and mechanisms, from single block falls to mass falls. Several rockfall events occurred between 1981 and 2010 motivated the design of slope benching and a massive embankment. To support reliable design verification and optimization we performed a 3D assessment of both rock slope instability and rockfall runout. We characterised fracture patterns and rock mass quality associated

  4. Supervised Detection of Anomalous Light Curves in Massive Astronomical Catalogs

    NASA Astrophysics Data System (ADS)

    Nun, Isadora; Pichara, Karim; Protopapas, Pavlos; Kim, Dae-Won

    2014-09-01

    The development of synoptic sky surveys has led to a massive amount of data for which resources needed for analysis are beyond human capabilities. In order to process this information and to extract all possible knowledge, machine learning techniques become necessary. Here we present a new methodology to automatically discover unknown variable objects in large astronomical catalogs. With the aim of taking full advantage of all information we have about known objects, our method is based on a supervised algorithm. In particular, we train a random forest classifier using known variability classes of objects and obtain votes for each of the objects in the training set. We then model this voting distribution with a Bayesian network and obtain the joint voting distribution among the training objects. Consequently, an unknown object is considered as an outlier insofar it has a low joint probability. By leaving out one of the classes on the training set, we perform a validity test and show that when the random forest classifier attempts to classify unknown light curves (the class left out), it votes with an unusual distribution among the classes. This rare voting is detected by the Bayesian network and expressed as a low joint probability. Our method is suitable for exploring massive data sets given that the training process is performed offline. We tested our algorithm on 20 million light curves from the MACHO catalog and generated a list of anomalous candidates. After analysis, we divided the candidates into two main classes of outliers: artifacts and intrinsic outliers. Artifacts were principally due to air mass variation, seasonal variation, bad calibration, or instrumental errors and were consequently removed from our outlier list and added to the training set. After retraining, we selected about 4000 objects, which we passed to a post-analysis stage by performing a cross-match with all publicly available catalogs. Within these candidates we identified certain known

  5. Spin-up of massive classical bulges during secular evolution

    NASA Astrophysics Data System (ADS)

    Saha, Kanak; Gerhard, Ortwin; Martinez-Valpuesta, Inma

    2016-04-01

    Context. Classical bulges in spiral galaxies are known to rotate, but the origin of this observed rotational motion is not well understood. It has been shown recently that a low-mass classical bulge (ClB) in a barred galaxy can acquire rotation by absorbing a significant fraction of the angular momentum emitted by the bar. Aims: Our aim here is to investigate whether bars can also spin up more massive ClBs during the secular evolution of the bar, and to study the kinematics and dynamics of these ClBs. Methods: We use a set of self-consistent N-body simulations to study the interaction of ClBs with a bar that forms self-consistently in the disk. We use orbital spectral analysis to investigate the angular momentum gain by the classical bulge stars. Results: We show that the ClBs gain on average 2-6% of the disk's initial angular momentum within the bar region. Most of this angular momentum gain occurs via low-order resonances, particularly 5:2 resonant orbits. A density wake forms in the ClB which corotates and aligns with the bar at the end of the evolution. The spin-up process creates a characteristic linear rotation profile and mild tangential anisotropy in the ClB. The induced rotation is small in the centre, but is significant beyond ~2 bulge half mass radii, where it leads to mass-weighted V/σ ~ 0.2, and reaches a local Vmax/σin ~ 0.5 at around the scale of the bar. The resulting V/σ is tightly correlated with the ratio of the bulge size to the bar size. In all models, a box/peanut bulge forms suggesting that composite bulges may be common. Conclusions: Bar-bulge resonant interaction in barred galaxies can provide some spin-up of massive ClBs, but the process appears to be less efficient than for low-mass ClBs. Further angular momentum transfer due to nuclear bars or gas inflow would be required to explain the observed rotation if it is not primordial.

  6. X-ray emission of hot massive stars

    NASA Astrophysics Data System (ADS)

    Oskinova, L.

    2014-07-01

    Massive hot stars are important cosmic engines that severely influence their environment by powerful stellar wind and strong ionizing radiation. Modern observations of X-ray emission from massive stars provide deep insight into the structure and dynamics of their winds and allow to study the very hot gas in wind blown bubbles. I will review the recent findings on X-ray emission from OB and Wolf-Rayet stars and massive star clusters. While our knowledge about the X-ray emission from massive stars is increasing, a small fraction of massive stars that have strong magnetic fields are often unusual in their X-ray light. Massive star clusters provide an excellent opportunity to study stellar feedback and the hot gas filling the intracluster medium. The most massive stars are often binaries where the stellar winds collide and produce X-ray or even gamma-ray radiation. Finally, I will discuss the progress towards an unified view of stellar winds in single stars and in high mass X-ray binaries.

  7. Recent results on the connection between massive stars and supernovae

    NASA Astrophysics Data System (ADS)

    Hillier, D. John

    2015-08-01

    With the dramatic increase in observational data on supernovae (SNe), SN studies are undergoing a renaissance. It is known that Type II SN IIP arise from the explosion of a red supergiant (RSG). In several cases the RSG is seen in pre-explosion images, but it is absent in post-SN images — unambiguous proof that the RSG has exploded. Surprisingly, all RSG progenitors identified have a mass less than approximately 20 M⊙. To date, there has been no direct detection of the progenitor of a Type Ib or Ic SN. Because their ejecta masses are generally low (3 to 5 M⊙), these SNe are believed to arise from a relatively low mass star in a binary system. Such systems dominate the statistics due to the initial mass function. The broad-lined Ic SNe tend to have higher mass, and some of these may be associated with classic Wolf-Rayet (W-R) stars. Type IIn SNe are a heterogeneous class of SN — they arise when the SN ejecta interacts with preexisting circumstellar material. Their spectra often exhibit narrow emission lines, and they can be particularly luminous due to the efficient conversion of kinetic energy into radiation. The origin of Type IIn SN and their connection to stellar evolution is the subject of fierce debate and controversy. The final class to be discussed are the pair-instability supernovae (PISNe) which arise from a nuclear detonation. PISNe have a distinct chemical signature, and the observational evidence for the existence of this class of SN is ambiguous and controversial. While much progress has been made, it is still difficult to get models of core-collapse SNe to explode from first principles. The problem is inherently 3D and numerous questions remain unanswered. How much material falls back onto the core? What is the nature and extent of mixing in the ejecta? What are the chemical yields? Do all massive stars end their life as a luminous SN?

  8. Complete Stellar Models: Spectral and Interior Evolution of Massive Stars

    NASA Astrophysics Data System (ADS)

    Schaerer, Daniel

    1995-08-01

    This thesis work presents the first "complete stellar models" for massive stars, which consistently treat the stellar interior, the atmosphere, and the stellar winds. This approach allows to simultaneously predict basic stellar parameters (luminosity, radii, temperatures), nucleosynthesis (abundances), as well as the detailed emergent spectrum through the relevant evolutionary phases (corresponding to OB, LBV and Wolf--Rayet stars). On the other hand, our modelling including the stellar winds also allows to study the influence of the outer layers on the stellar structure and evolution. Conceptually the thesis is divided in two main parts. In the first part we construct the first non-LTE line blanketed hydrodynamic models of spherically expanding atmospheres of hot stars. The entire domain from the optically thick photosphere out to the terminal velocity of the wind is treated. We discuss in detail the effects of line blanketing on the atmospheric structure and on the predicted spectrum. We study the influence of the hydrodynamic structure on the profiles of both photospheric and wind lines. Our results also show that for precise determinations of stellar parameters and abundances of hot luminous stars, the use of plane parallel models may lead to systematic errors. In the second part we develop the "complete stellar models" (CoStar). As a first application we study the main sequence (MS) interior and spectral evolution of massive stars at solar metallicity. The evolutionary tracks and the interior evolution are found to be basically unchanged by the realistic treatment of the outer layers. The main CoStar predictions presented and discussed for the MS are the following: 1. Ejected mass of the most important elements. Deposition of wind momentum and mechanical energy 2. Estimates of mass loss rates due to radiation pressure including multiple scattering and line overlap 3. Continuous spectral energy distribution (EUV to IR) and ionising fluxes 4. UBVRIJHKLMN

  9. Massive Black Hole Implicated in Stellar Destruction

    NASA Astrophysics Data System (ADS)

    2010-01-01

    New results from NASA's Chandra X-ray Observatory and the Magellan telescopes suggest that a dense stellar remnant has been ripped apart by a black hole a thousand times as massive as the Sun. If confirmed, this discovery would be a cosmic double play: it would be strong evidence for an intermediate mass black hole, which has been a hotly debated topic, and would mark the first time such a black hole has been caught tearing a star apart. This scenario is based on Chandra observations, which revealed an unusually luminous source of X-rays in a dense cluster of old stars, and optical observations that showed a peculiar mix of elements associated with the X-ray emission. Taken together, a case can be made that the X-ray emission is produced by debris from a disrupted white dwarf star that is heated as it falls towards a massive black hole. The optical emission comes from debris further out that is illuminated by these X-rays. The intensity of the X-ray emission places the source in the "ultraluminous X-ray source" or ULX category, meaning that it is more luminous than any known stellar X-ray source, but less luminous than the bright X-ray sources (active galactic nuclei) associated with supermassive black holes in the nuclei of galaxies. The nature of ULXs is a mystery, but one suggestion is that some ULXs are black holes with masses between about a hundred and several thousand times that of the Sun, a range intermediate between stellar-mass black holes and supermassive black holes located in the nuclei of galaxies. This ULX is in a globular cluster, a very old and crowded conglomeration of stars. Astronomers have suspected that globular clusters could contain intermediate-mass black holes, but conclusive evidence for this has been elusive. "Astronomers have made cases for stars being torn apart by supermassive black holes in the centers of galaxies before, but this is the first good evidence for such an event in a globular cluster," said Jimmy Irwin of the University

  10. Two-dimensional thermofield bosonization II: Massive fermions

    SciTech Connect

    Amaral, R.L.P.G.

    2008-11-15

    We consider the perturbative computation of the N-point function of chiral densities of massive free fermions at finite temperature within the thermofield dynamics approach. The infinite series in the mass parameter for the N-point functions are computed in the fermionic formulation and compared with the corresponding perturbative series in the interaction parameter in the bosonized thermofield formulation. Thereby we establish in thermofield dynamics the formal equivalence of the massive free fermion theory with the sine-Gordon thermofield model for a particular value of the sine-Gordon parameter. We extend the thermofield bosonization to include the massive Thirring model.

  11. Massive gravity with mass term in three dimensions

    SciTech Connect

    Nakasone, Masashi; Oda, Ichiro

    2009-05-15

    We analyze the effect of the Pauli-Fierz mass term on a recently established, new massive gravity theory in three space-time dimensions. We show that the Pauli-Fierz mass term makes the new massive gravity theory nonunitary. Moreover, although we add the gravitational Chern-Simons term to this model, the situation remains unchanged and the theory stays nonunitary despite that the structure of the graviton propagator is greatly changed. Thus, the Pauli-Fierz mass term is not allowed to coexist with mass-generating higher-derivative terms in the new massive gravity.

  12. Large N phase transitions in massive N = 2 gauge theories

    SciTech Connect

    Russo, J. G.

    2014-07-23

    Using exact results obtained from localization on S{sup 4}, we explore the large N limit of N = 2 super Yang-Mills theories with massive matter multiplets. In this talk we discuss two cases: N = 2* theory, describing a massive hypermultiplet in the adjoint representation, and super QCD with massive quarks. When the radius of the four-sphere is sent to infinity these theories are described by solvable matrix models, which exhibit a number of interesting phenomena including quantum phase transitions at finite 't Hooft coupling.

  13. Fundamental Parameters of 4 Massive Eclipsing Binaries in Westerlund 1

    NASA Astrophysics Data System (ADS)

    Bonanos, Alceste Z.; Koumpia, E.

    2011-05-01

    We present fundamental parameters of 4 massive eclipsing binaries in the young massive cluster Westerlund 1. The goal is to measure accurate masses and radii of their component stars, which provide much needed constraints for evolutionary models of massive stars. Accurate parameters can further be used to determine a dynamical lower limit for the magnetar progenitor and to obtain an independent distance to the cluster. Our results confirm and extend the evidence for a high mass for the progenitor of the magnetar. The authors acknowledge research and travel support from the European Commission Framework Program Seven under the Marie Curie International Reintegration Grant PIRG04-GA-2008-239335.

  14. Remarks on search methods for stable, massive, elementary particles

    NASA Astrophysics Data System (ADS)

    Perl, Martin L.

    2001-11-01

    This paper was presented at the 69th birthday celebration of Professor Eugene Commins, honoring his research achievements. These remarks are about the experimental techniques used in the search for new stable, massive particles, particles at least as massive as the electron. A variety of experimental methods such as accelerator experiments, cosmic ray studies, searches for halo particles in the galaxy and searches for exotic particles in bulk matter are described. A summary is presented of the measured limits on the existence of new stable, massive particle. .

  15. Massive air embolus treated with rheolytic thrombectomy.

    PubMed

    Dudar, Basil M; Kim, Henry E

    2007-07-01

    The incidence of air embolism during diagnostic cardiac catheterization and percutaneous coronary intervention is reported at a rate of 0.84% and 0.24%. Although there is no optimal technique to restore blood flow after blockage by air emboli, treatment options include manual aspiration or forcefully injecting saline, with auxiliary supportive measures like 100% oxygen or an intra-aortic balloon pump. The AngioJet (Possis Medical, Inc., Minneapolis, Minnesota) device is a catheter-based device for thrombus removal in which high-velocity saline jets are used to create a localized low-pressure zone at the distal catheter tip (Bernoulli effect), resulting in the maceration and removal of thrombus through an exhaust lumen. The use of rheolytic thrombectomy has been studied in thrombus-containing native coronary arteries as well as saphenous vein graft lesions. We report a case of a massive air embolus that occurred after activation of an AngioJet catheter in a thrombus-laden right coronary artery (RCA). The AngioJet catheter was then utilized to effectively aspirate the air embolus with restoration of coronary blood flow. Use of a guiding catheter that is nonocclusive or with side holes to ensure continuous blood flow from the central aorta may help avoid entrainment of air into the coronary artery during activation of the AngioJet thrombectomy catheter. To our knowledge, this is the first reported case of such a potential complication. In the event of such a complication, the AngioJet catheter can be implemented to aspirate a coronary air embolus. PMID:17620682

  16. SEGUE 2: THE LEAST MASSIVE GALAXY

    SciTech Connect

    Kirby, Evan N.; Boylan-Kolchin, Michael; Bullock, James S.; Kaplinghat, Manoj; Cohen, Judith G.; Geha, Marla

    2013-06-10

    Segue 2, discovered by Belokurov et al., is a galaxy with a luminosity of only 900 L{sub Sun }. We present Keck/DEIMOS spectroscopy of 25 members of Segue 2-a threefold increase in spectroscopic sample size. The velocity dispersion is too small to be measured with our data. The upper limit with 90% (95%) confidence is {sigma}{sub v} < 2.2 (2.6) km s{sup -1}, the most stringent limit for any galaxy. The corresponding limit on the mass within the three-dimensional half-light radius (46 pc) is M{sub 1/2} < 1.5 (2.1) Multiplication-Sign 10{sup 5} M{sub Sun }. Segue 2 is the least massive galaxy known. We identify Segue 2 as a galaxy rather than a star cluster based on the wide dispersion in [Fe/H] (from -2.85 to -1.33) among the member stars. The stars' [{alpha}/Fe] ratios decline with increasing [Fe/H], indicating that Segue 2 retained Type Ia supernova ejecta despite its presently small mass and that star formation lasted for at least 100 Myr. The mean metallicity, ([Fe/H]) = -2.22 {+-} 0.13 (about the same as the Ursa Minor galaxy, 330 times more luminous than Segue 2), is higher than expected from the luminosity-metallicity relation defined by more luminous dwarf galaxy satellites of the Milky Way. Segue 2 may be the barest remnant of a tidally stripped, Ursa Minor-sized galaxy. If so, it is the best example of an ultra-faint dwarf galaxy that came to be ultra-faint through tidal stripping. Alternatively, Segue 2 could have been born in a very low mass dark matter subhalo (v{sub max} < 10 km s{sup -1}), below the atomic hydrogen cooling limit.

  17. Electrical properties of seafloor massive sulfides

    NASA Astrophysics Data System (ADS)

    Spagnoli, Giovanni; Hannington, Mark; Bairlein, Katharina; Hördt, Andreas; Jegen, Marion; Petersen, Sven; Laurila, Tea

    2016-06-01

    Seafloor massive sulfide (SMS) deposits are increasingly seen as important marine metal resources for the future. A growing number of industrialized nations are involved in the surveying and sampling of such deposits by drilling. Drill ships are expensive and their availability can be limited; seabed drill rigs are a cost-effective alternative and more suitable for obtaining cores for resource evaluation. In order to achieve the objectives of resource evaluations, details are required of the geological, mineralogical, and physical properties of the polymetallic deposits and their host rocks. Electrical properties of the deposits and their ore minerals are distinct from their unmineralized host rocks. Therefore, the use of electrical methods to detect SMS while drilling and recovering drill cores could decrease the costs and accelerate offshore operations by limiting the amount of drilling in unmineralized material. This paper presents new data regarding the electrical properties of SMS cores that can be used in that assessment. Frequency-dependent complex electrical resistivity in the frequency range between 0.002 and 100 Hz was examined in order to potentially discriminate between different types of fresh rocks, alteration and mineralization. Forty mini-cores of SMS and unmineralized host rocks were tested in the laboratory, originating from different tectonic settings such as the intermediate-spreading ridges of the Galapagos and Axial Seamount, and the Pacmanus back-arc basin. The results indicate that there is a clear potential to distinguish between mineralized and non-mineralized samples, with some evidence that even different types of mineralization can be discriminated. This could be achieved using resistivity magnitude alone with appropriate rig-mounted electrical sensors. Exploiting the frequency-dependent behavior of resistivity might amplify the differences and further improve the rock characterization.

  18. Fault tolerant massively parallel processing architecture

    SciTech Connect

    Balasubramanian, V.; Banerjee, P.

    1987-08-01

    This paper presents two massively parallel processing architectures suitable for solving a wide variety of algorithms of divide-and-conquer type for problems such as the discrete Fourier transform, production systems, design automation, and others. The first architecture, called the Chain-structured Butterfly ARchitecture (CBAR), consists of a two-dimensional array of N-L . (log/sub 2/(L)+1) processing elements (PE) organized as L levels of log/sub 2/(L)+1 stages, and which has the butterfly connection between PEs in consecutive stages with straight-through feedback between PEs in the last and first stages. This connection system has the desirable property of allowing thousands of PEs to be connected with O(N) connection cost, O(log/sub 2/(N/log/sub 2/N)) communication paths, and a small number (=4) of I/O ports per PE. However, this architecture is not fault tolerant. The authors, therefore, propose a second architecture, called the REconfigurable Chain-structured Butterfly ARchitecture (RECBAR), which is a modified version of the CBAR. The RECBAR possesses all the desirable features of the CBAR, with the number of I/O ports per PE increased to six, and uses O(log/sub 2/N)/N) overhead in PEs and approximately 50% overhead in links to achieve single-level fault tolerance. Reliability improvements of the RECBAR over the CBAR are studied. This paper also presents a distributed diagnostic and structuring algorithm for the RECBAR that enables the architecture to detect faults and structure itself accordingly within 2 . log/sub 2/(L)+1 time steps, thus making it a truly fault tolerant architecture.

  19. Massive subcritical compact arrays of plutonium metal

    SciTech Connect

    Rothe, R.E.

    1998-04-01

    Two experimental critical-approach programs are reported. Both were performed at the Rocky Flats Plant near Denver, Colorado; and both date back to the late 1960s. Both involve very large arrays of massive plutonium ingots. These ingots had been cast in the foundry at the Rocky Flats Plant as part of their routine production operations; they were not specially prepared for either study. Consequently, considerable variation in ingot mass is encountered. This mass varied between approximately 7 kg and a little more than 10 kg. One program, performed in the spring of 1969, involved stacked arrays of ingots contained within cylindrical, disk-shaped, thin, steel cans. This program studied four arrays defined by the pattern of steel cans in a single layer. The four were: 1 x N, 3 x N, 2 x 2 x N, and 3 x 3 x N. The second was a tightly-packed, triangular-pitched patterns; the last two were square-pitched patterns. The other program, performed about a year earlier, involved similar ingots also contained in similar steel cans, but these canned plutonium ingots were placed in commercial steel drums. This study pertained to one-, two-, and three-layered horizontal arrays of drums. All cases proved to be well subcritical. Most would have remained subcritical had the parameters of the array under study been continued infinitely beyond the reciprocal multiplication safety limit. In one case for the drum arrays, an uncertain extrapolation of the data of the earlier program suggests that criticality might have eventually been attained had several thousand additional kilograms of plutonium been available for use.

  20. The massive monsters living deep in the Tarantula nebula: How massive are they really?

    NASA Astrophysics Data System (ADS)

    de Mink, Selma

    2013-10-01

    The recent suggestion that stars with masses in excess of about 300 solar masses exist in the dense star cluster R136 at heart of the Tarantula Nebula received wide interest. It reopened the debate about the upper stellar-mass limit of the initial mass function {IMF} and it raised the question whether pair-instability supernovae - originally thought exclusively originate from first generation of pop III stars - can occur in the vicinity of Milky Way.A major challenge hampering mass estimates of the most massive stars is crowding and unresolved companions. High-resolution imaging from the ground and with HST reaching resolutions of about 0.1 arcsec resolved the brightest source in R136 into three separate components. Unfortunately, the extreme crowding and faintness of the targets prohibits ground-based facilities to reach further towards mili-arcsecond resolution.We propose to exploit the new full two-dimensional calibration program of Fine Guidance Sensor {Nelan, Prop ID 13175} to probe the most luminous stars in R136 for previously unseen companions down to a resolution of 12 mili-arsecond, exploring the separation of about 500-5000 AU. Furthermore, we will characterize the claimed source R136-a1B and if needed revise downward the mass estimates of the most massive stars known date.

  1. Alum irrigation in massive bladder hemorrhage in severe renal failure.

    PubMed

    Modi, K B; Paterson, P J

    1988-09-01

    We report a patient with severe renal failure in whom massive bladder hemorrhage was successfully treated with alum irrigation. There was no substantial potassium or aluminum absorption with alum irrigation.

  2. A Massive Intratumoral Aneurysmal Vessel in a Retroperitoneal Lipoblastoma.

    PubMed

    Moon, Suk-Bae

    2015-12-01

    Lipoblastoma is a benign tumor and usually does not require radical operation for complete excision. We describe here a case of a retroperitoneal lipoblastoma with a massive intratumoral aneurysmal vessel.

  3. Understanding the size growth of massive galaxies through stellar populations

    NASA Astrophysics Data System (ADS)

    Ferreras, Ignacio

    2015-08-01

    The growth of massive galaxies remains an open problem. The observational evidence seems to converge on a two-stage scenario, where a compact massive core is formed during an early, intense burst, followed by a more extended process of mass and size growth at intermediate redshift (z<2). This talk focuses on the latter, exploring the growth of massive galaxies through a detailed analysis of the stellar populations in close pairs, to study their formation history. Two surveys are explored (SHARDS and GAMA), probing the stellar populations of pre-merging systems out to z~1.3, and down to a mass ratio ~1:100. We will compare the results between medium band spectral fitting (SHARDS) and those from a more targeted analysis of line strengths in the GAMA data. The combination of the two datasets provide a unique insight of the growth channel of massive galaxies via mergers.

  4. Generalized massive gravity in arbitrary dimensions and its Hamiltonian formulation

    SciTech Connect

    Huang, Qing-Guo; Zhang, Ke-Chao; Zhou, Shuang-Yong E-mail: zkc@itp.ac.cn

    2013-08-01

    We extend the four-dimensional de Rham-Gabadadze-Tolley (dRGT) massive gravity model to a general scalar massive-tensor theory in arbitrary dimensions, coupling a dRGT massive graviton to multiple scalars and allowing for generic kinetic and mass matrix mixing between the massive graviton and the scalars, and derive its Hamiltonian formulation and associated constraint system. When passing to the Hamiltonian formulation, two different sectors arise: a general sector and a special sector. Although obtained via different ways, there are two second class constraints in either of the two sectors, eliminating the BD ghost. However, for the special sector, there are still ghost instabilities except for the case of two dimensions. In particular, for the special sector with one scalar, there is a ''second BD ghost''.

  5. Magnetically regulated fragmentation of a massive, dense, and turbulent clump

    NASA Astrophysics Data System (ADS)

    Fontani, F.; Commerçon, B.; Giannetti, A.; Beltrán, M. T.; Sánchez-Monge, A.; Testi, L.; Brand, J.; Caselli, P.; Cesaroni, R.; Dodson, R.; Longmore, S.; Rioja, M.; Tan, J. C.; Walmsley, C. M.

    2016-09-01

    Massive stars, multiple stellar systems, and clusters are born of the gravitational collapse of massive, dense, gaseous clumps, and the way these systems form strongly depends on how the parent clump fragments into cores during collapse. Numerical simulations show that magnetic fields may be the key ingredient in regulating fragmentation. Here we present ALMA observations at ~ 0.25'' resolution of the thermal dust continuum emission at ~ 278 GHz towards a turbulent, dense, and massive clump, IRAS 16061-5048c1, in a very early evolutionary stage. The ALMA image shows that the clump has fragmented into many cores along a filamentary structure. We find that the number, the total mass, and the spatial distribution of the fragments are consistent with fragmentation dominated by a strong magnetic field. Our observations support the theoretical prediction that the magnetic field plays a dominant role in the fragmentation process of massive turbulent clumps.

  6. 38. Tap room fireplace, showing massive open timber trusses, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    38. Tap room fireplace, showing massive open timber trusses, view looking to southeast. (fixtures and mantle removed 1999). - Fort Ord, Soldiers' Club, California State Highway 1 near Eighth Street, Seaside, Monterey County, CA

  7. The EMCC / DARPA Massively Parallel Electromagnetic Scattering Project

    NASA Technical Reports Server (NTRS)

    Woo, Alex C.; Hill, Kueichien C.

    1996-01-01

    The Electromagnetic Code Consortium (EMCC) was sponsored by the Advanced Research Program Agency (ARPA) to demonstrate the effectiveness of massively parallel computing in large scale radar signature predictions. The EMCC/ARPA project consisted of three parts.

  8. Cosmological constraints on the properties of weakly interacting massive particles

    SciTech Connect

    Steigman, G.; Turner, M.S.

    1984-10-01

    Considerations of the age and density of, as well as the evolution of structure in, the Universe lead to constraints on the masses and lifetimes of weakly interacting massive particles (WIMPs). 26 references.

  9. 16. FLOOR 1; MASSIVE CENTER POST IS THE MAIN POST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. FLOOR 1; MASSIVE CENTER POST IS THE MAIN POST OF A 1736 POST MILL WHICH THIS MILL REPLACED; MORTISE FOR QUARTER BAR CAN BE SEEN - Hook Windmill, North Main Street at Pantigo Road, East Hampton, Suffolk County, NY

  10. The Unevolved Massive Star Content of the Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    Massey, Philip

    2012-10-01

    The Magellanic Clouds offer a unique astrophysical laboratory where we can actually obtain an unbiased estimate of the number of unevolved massive stars above a certain mass. Comparing this number with the {known} number of evolved massive stars, such as Wolf-Rayets, yellow supergiants, and red supergiants, provides a hiterto unavailable test of massive star evolutionary theory. We are engaged in a long-term {5 year} effort to characterize the massive star content of select OB associations of the SMC and LMC using spectroscopy with the Magellan 6.5-m telescopes. Here we are asking for a short { 1 sec} SNAPshot of each of 23 OB associations in the F225W filter. These HST data will provide a crucial complement to our ground based data, allowing us to concentrate on the early and mid O-type stars with our spectroscopy, and to recognize close doubles that would otherwise be unrecognized from the ground.

  11. Quark-hadron phase transition in massive gravity

    NASA Astrophysics Data System (ADS)

    Atazadeh, K.

    2016-11-01

    We study the quark-hadron phase transition in the framework of massive gravity. We show that the modification of the FRW cosmological equations leads to the quark-hadron phase transition in the early massive Universe. Using numerical analysis, we consider that a phase transition based on the chiral symmetry breaking after the electroweak transition, occurred at approximately 10 μs after the Big Bang to convert a plasma of free quarks and gluons into hadrons.

  12. Active feedback cooling of massive electromechanical quartz resonators

    SciTech Connect

    Jahng, Junghoon; Lee, Manhee; Stambaugh, Corey; Bak, Wan; Jhe, Wonho

    2011-08-15

    We present a general active feedback cooling scheme for massive electromechanical quartz resonators. We cool down two kinds of macrosized quartz tuning forks and find several characteristic constants for this massive quartz-resonator feedback cooling, in good agreement with theoretical calculations. When combined with conventional cryogenic techniques and low-noise devices, one may reach the quantum sensitivity for macroscopic sensors. This may be useful for high sensitivity measurements and for quantum information studies.

  13. Experimental free-space optical network for massively parallel computers

    NASA Astrophysics Data System (ADS)

    Araki, S.; Kajita, M.; Kasahara, K.; Kubota, K.; Kurihara, K.; Redmond, I.; Schenfeld, E.; Suzaki, T.

    1996-03-01

    A free-space optical interconnection scheme is described for massively parallel processors based on the interconnection-cached network architecture. The optical network operates in a circuit-switching mode. Combined with a packet-switching operation among the circuit-switched optical channels, a high-bandwidth, low-latency network for massively parallel processing results. The design and assembly of a 64-channel experimental prototype is discussed, and operational results are presented.

  14. Design of Massive-MIMO-NOMA With Limited Feedback

    NASA Astrophysics Data System (ADS)

    Ding, Zhiguo; Poor, H. Vincent

    2016-05-01

    In this letter, a low-feedback non-orthogonal multiple access (NOMA) scheme using massive multiple-input multiple-output (MIMO) transmission is proposed. In particular, the proposed scheme can decompose a massive-MIMO-NOMA system into multiple separated single-input single-output NOMA channels, and analytical results are developed to evaluate the performance of the proposed scheme for two scenarios, with perfect user ordering and with one-bit feedback, respectively.

  15. Unitarity cuts with massive propagators and algebraic expressions for coefficients

    SciTech Connect

    Britto, Ruth; Feng Bo

    2007-05-15

    In the first part of this paper, we extend the d-dimensional unitarity cut method of Anastasiou et al. to cases with massive propagators. We present formulas for integral reduction with which one can obtain coefficients of all pentagon, box, triangle and massive bubble integrals. In the second part of this paper, we present a detailed study of the phase space integration for unitarity cuts. We carry out spinor integration in generality and give algebraic expressions for coefficients, intended for automated evaluation.

  16. Massive basketball diagram for a thermal scalar field theory

    NASA Astrophysics Data System (ADS)

    Andersen, Jens O.; Braaten, Eric; Strickland, Michael

    2000-08-01

    The ``basketball diagram'' is a three-loop vacuum diagram for a scalar field theory that cannot be expressed in terms of one-loop diagrams. We calculate this diagram for a massive scalar field at nonzero temperature, reducing it to expressions involving three-dimensional integrals that can be easily evaluated numerically. We use this result to calculate the free energy for a massive scalar field with a φ4 interaction to three-loop order.

  17. Reconstructing the massive black hole cosmic history through gravitational waves

    SciTech Connect

    Sesana, Alberto; Gair, Jonathan; Berti, Emanuele; Volonteri, Marta

    2011-02-15

    The massive black holes we observe in galaxies today are the natural end-product of a complex evolutionary path, in which black holes seeded in proto-galaxies at high redshift grow through cosmic history via a sequence of mergers and accretion episodes. Electromagnetic observations probe a small subset of the population of massive black holes (namely, those that are active or those that are very close to us), but planned space-based gravitational wave observatories such as the Laser Interferometer Space Antenna (LISA) can measure the parameters of 'electromagnetically invisible' massive black holes out to high redshift. In this paper we introduce a Bayesian framework to analyze the information that can be gathered from a set of such measurements. Our goal is to connect a set of massive black hole binary merger observations to the underlying model of massive black hole formation. In other words, given a set of observed massive black hole coalescences, we assess what information can be extracted about the underlying massive black hole population model. For concreteness we consider ten specific models of massive black hole formation, chosen to probe four important (and largely unconstrained) aspects of the input physics used in structure formation simulations: seed formation, metallicity ''feedback'', accretion efficiency and accretion geometry. For the first time we allow for the possibility of 'model mixing', by drawing the observed population from some combination of the 'pure' models that have been simulated. A Bayesian analysis allows us to recover a posterior probability distribution for the ''mixing parameters'' that characterize the fractions of each model represented in the observed distribution. Our work shows that LISA has enormous potential to probe the underlying physics of structure formation.

  18. Geometrothermodynamics of black holes in Lorentz noninvariant massive gravity

    NASA Astrophysics Data System (ADS)

    Sánchez, Alberto

    2016-07-01

    We analyze a static and spherically symmetric hairy black hole solution in noninvariant massive gravity. The formalism of geometrothermodynamics is used to describe the thermodynamic characteristics of this black hole in a Legendre invariant way. For a black hole in massive gravity, the geometry of the space of equilibrium states is computed showing that it contains information about the thermodynamic interaction, critical points, and phase transitions structure.

  19. Massive Young Star Clusters in M33: Stochastic Star Formation Ruled Out

    NASA Astrophysics Data System (ADS)

    González-Lópezlira, R. A.; Pflamm-Altenburg, J.; Kroupa, P.

    2014-09-01

    It is widely accepted that the distribution function of the masses of young star clusters is universal and can be purely interpreted as a probability density distribution function with a constant upper mass limit. As a result of this picture, the masses of the most massive objects would be exclusively determined by the size of the sample. Conversely we show, with very high confidence, that the masses of the most massive young (< 10 Myr) star clusters in the flocculent galaxy M33 decrease with increasing galactocentric radius, in contradiction with a constant shape and upper mass limit of the cluster mass function. Moreover, by comparing the radial distributions of gas surface densities and highest cluster masses, we find that M_{max} ∝ Σ_{gas, total}^{3.8 ± 0.3}, M_{max} ∝ Σ_{H_2}^{1.2± 0.1} and M_{max} ∝ Σ_{SFR}^{0.9 ± 0.1}. Hence, in M33 we can rule out stochastic star formation. The change of the maximum cluster mass there must be due to physical causes, i.e., very massive star clusters may require special physical conditions, like high gas surface densities, in order to form.

  20. AN UPPER LIMIT TO THE VELOCITY DISPERSION OF RELAXED STELLAR SYSTEMS WITHOUT MASSIVE BLACK HOLES

    SciTech Connect

    Miller, M. Coleman; Davies, Melvyn B.

    2012-08-10

    Massive black holes have been discovered in all closely examined galaxies with high velocity dispersion. The case is not as clear for lower-dispersion systems such as low-mass galaxies and globular clusters. Here we suggest that above a critical velocity dispersion {approx}40 km s{sup -1}, massive central black holes will form in relaxed stellar systems at any cosmic epoch. This is because above this dispersion primordial binaries cannot support the system against deep core collapse. If, as previous simulations show, the black holes formed in the cluster settle to produce a dense subcluster, then given the extremely high densities reached during core collapse the holes will merge with each other. For low velocity dispersions and hence low cluster escape speeds, mergers will typically kick out all or all but one of the holes due to three-body kicks or the asymmetric emission of gravitational radiation. If one hole remains, it will tidally disrupt stars at a high rate. If none remain, one is formed after runaway collisions between stars, and then it tidally disrupts stars at a high rate. The accretion rate after disruption is many orders of magnitude above Eddington. If, as several studies suggest, the hole can accept matter at that rate because the generated radiation is trapped and advected, then it will grow quickly and form a massive central black hole.

  1. Satellites around Massive Galaxies Since z ~ 2: Confronting the Millennium Simulation with Observations

    NASA Astrophysics Data System (ADS)

    Quilis, Vicent; Trujillo, Ignacio

    2012-06-01

    Minor merging has been postulated as the most likely evolutionary path to produce the increase in size and mass observed in the massive galaxies since z ~ 2. In this Letter, we directly test this hypothesis, comparing the population of satellites around massive galaxies in cosmological simulations versus the observations. We use state-of-the-art, publically available, Millennium I and II simulations, and the associated semi-analytical galaxy catalogs to explore the time evolution of the fraction of massive galaxies that have satellites, the number of satellites per galaxy, the projected distance at which the satellites locate from the host galaxy, and the mass ratio between the host galaxies and their satellites. The three virtual galaxy catalogs considered here overproduce the fraction of galaxies with satellites by a factor ranging between 1.5 and 6 depending on the epoch, whereas the mean projected distance and ratio of the satellite mass over host mass are in closer agreement with data. The larger pull of satellites in the semi-analytical samples could suggest that the size evolution found in previous hydrodynamical simulations is an artifact due to the larger number of infalling satellites compared to the real universe. These results advise us to revise the physical ingredients implemented in the semi-analytical models in order to reconcile the observed and computed fraction of galaxies with satellites, and eventually, it would leave some room for other mechanisms explaining the galaxy size growth not related to the minor merging.

  2. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands.

    PubMed

    Maruta, Kazuki; Iwakuni, Tatsuhiko; Ohta, Atsushi; Arai, Takuto; Shirato, Yushi; Kurosaki, Satoshi; Iizuka, Masataka

    2016-01-01

    Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity. PMID:27399715

  3. High Energy Interactions in Massive Binaries: An Application to a Most Mysterious Binary

    NASA Technical Reports Server (NTRS)

    Corcoran, Michael

    2013-01-01

    Extremely massive stars (50M and above) are exceedingly rare in the local Universe but are believed to have composed the entire first generation of stars, which lived fast, died young and left behind the first generation of black holes and set the stage for the formation of lower mass stars suitable to support life. There are significant uncertainties about how this happened (and how it still happens), mostly due to our poor knowledge of how stars change mass as they evolve. Extremely massive stars give mass back to the ISM via strong radiatively-driven winds and sometimes through sporadic eruptions of the most massive and brightest stars. Such mass loss plays an important role in the chemical and dynamical evolution of the local interstellar medium prior to the supernova explosion. Below we discuss how high energy thermal (and, in some cases, non-thermal) emission, along with modern simulations in 2 and 3 dimensions, can be used to help determine a physically realistic picture of mass loss in a well-studied, mysterious system.

  4. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands

    PubMed Central

    Maruta, Kazuki; Iwakuni, Tatsuhiko; Ohta, Atsushi; Arai, Takuto; Shirato, Yushi; Kurosaki, Satoshi; Iizuka, Masataka

    2016-01-01

    Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity. PMID:27399715

  5. Pseudosarcoma – massive localized lymphoedema in morbidly obese – a rare entity: Case report

    PubMed Central

    Narayanarao, T.; Suvarchala, A.; Krishnababu, G.

    2012-01-01

    INTRODUCTION Massive localized lymphoedema (MLL) first described in 1998 by Farshid and Weiss. Usually MLL present like huge pedunculated mass and appear like sarcoma hence called Pseudosarcoma. Morbid obesity is a growing epidemic in our society. Morbid obesity is usually associated with hypertension, Diabetes mellitus, dermatological complications like Acanthosis nigricans, skin tags, leg ulcers, edema, lymphoedema, plantar hyperkeratosis and massive localized lymphoedema (MLL) is one of the complications of morbid obesity. Pseudosarcoma is due to derangement of lymphatic channels secondary to excessive deposition of adipose tissue. PRESENTATION OF CASE We report a patient afflicted with this unique disorder presented with huge mass arising from monspubis in morbidly obese individual with body mass index (BMI) 55. DISCUSSION Massive localized lymphedema presenting like pseudosarcoma in morbidly obese individuals is rare. Awareness of this disease is essential to avoid misdiagnosis as soft tissue neoplasm. It is a term used to describe a benign over growth of lymhoproliferative tissue in morbidly obese patients. Because of its size patients have difficult to do daily activities. Histopathologically characterized by dilated lymphatic channels with fibrotic and edematous tissue, without evidence of malignancy. Patient seeks treatment only if there is huge swelling causing discomfort, complications like excoriation, wound break down occur. The treatment of choice is complete excision. CONCLUSION Surgical treatment is effective if done along with bariatric surgery. Functional rehabilitation was achieved. No recurrence was observed within the follow up period of twenty months and BMI was reduced to 28. PMID:22651976

  6. FIRST SPECTROSCOPIC IDENTIFICATION OF MASSIVE YOUNG STELLAR OBJECTS IN THE GALACTIC CENTER

    SciTech Connect

    An, Deokkeun; Boogert, A. C. Adwin; RamIrez, Solange V.; Sellgren, Kris; Arendt, Richard G.; Stolovy, Susan R.; Cotera, Angela S.; Robitaille, Thomas P.; Smith, Howard A. E-mail: sellgren@astronomy.ohio-state.edu

    2009-09-10

    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 CO{sub 2} (15.0 {mu}m), C{sub 2}H{sub 2} (13.7 {mu}m), and HCN (14.0 {mu}m). We attribute this absorption to warm, dense gas in massive YSOs. We also detect strong and broad 15 {mu}m CO{sub 2} ice absorption features, with a remarkable double-peaked structure. The prominent long-wavelength peak is due to CH{sub 3}OH-rich ice grains, and is similar to those found in other known massive YSOs. Our IRS observations demonstrate the youth of these objects, and provide the first spectroscopic identification of massive YSOs in the Galactic Center.

  7. Effect of Turbulence Models on Two Massively-Separated Benchmark Flow Cases

    NASA Technical Reports Server (NTRS)

    Rumsey, Christopher L.

    2003-01-01

    Two massively-separated flow cases (the 2-D hill and the 3-D Ahmed body) were computed with several different turbulence models in the Reynolds-averaged Navier-Stokes code CFL3D as part of participation in a turbulence modeling workshop held in Poitiers, France in October, 2002. Overall, results were disappointing, but were consistent with results from other RANS codes and other turbulence models at the workshop. For the 2-D hill case, those turbulence models that predicted separation location accurately ended up yielding a too-long separation extent downstream. The one model that predicted a shorter separation extent in better agreement with LES data did so only by coincidence: its prediction of earlier reattachment was due to a too-late prediction of the separation location. For the Ahmed body, two slant angles were computed, and CFD performed fairly well for one of the cases (the larger slant angle). Both turbulence models tested in this case were very similar to each other. For the smaller slant angle, CFD predicted massive separation, whereas the experiment showed reattachment about half-way down the center of the face. These test cases serve as reminders that state- of-the-art CFD is currently not a reliable predictor of massively-separated flow physics, and that further validation studies in this area would be beneficial.

  8. Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars

    NASA Astrophysics Data System (ADS)

    Cristini, A.; Meakin, C.; Hirschi, R.; Arnett, D.; Georgy, C.; Viallet, M.

    2016-03-01

    Stellar evolution models of massive stars are important for many areas of astrophysics, for example nucleosynthesis yields, supernova progenitor models and understanding physics under extreme conditions. Turbulence occurs in stars primarily due to nuclear burning at different mass coordinates within the star. The understanding and correct treatment of turbulence and turbulent mixing at convective boundaries in stellar models has been studied for decades but still lacks a definitive solution. This paper presents initial results of a study on convective boundary mixing (CBM) in massive stars. The ‘stiffness’ of a convective boundary can be quantified using the bulk Richardson number ({{Ri}}{{B}}), the ratio of the potential energy for restoration of the boundary to the kinetic energy of turbulent eddies. A ‘stiff’ boundary ({{Ri}}{{B}}˜ {10}4) will suppress CBM, whereas in the opposite case a ‘soft’ boundary ({{Ri}}{{B}}˜ 10) will be more susceptible to CBM. One of the key results obtained so far is that lower convective boundaries (closer to the centre) of nuclear burning shells are ‘stiffer’ than the corresponding upper boundaries, implying limited CBM at lower shell boundaries. This is in agreement with 3D hydrodynamic simulations carried out by Meakin and Arnett (2007 Astrophys. J. 667 448-75). This result also has implications for new CBM prescriptions in massive stars as well as for nuclear burning flame front propagation in super-asymptotic giant branch stars and also the onset of novae.

  9. SUPERDENSE MASSIVE GALAXIES IN THE ESO DISTANT CLUSTER SURVEY (EDisCS)

    SciTech Connect

    Valentinuzzi, T.; D'onofrio, M.; Vulcani, B.; Poggianti, B. M.; Fritz, J.; Moretti, A.; Saglia, R. P.; Aragon-Salamanca, A.; Simard, L.; Sanchez-Blazquez, P.; Cava, A.; Couch, W. J.

    2010-09-20

    We find a significant number of massive and compact galaxies in clusters from the ESO Distant Clusters Survey (EDisCS) at 0.4 < z < 1. They have similar stellar masses, ages, sizes, and axial ratios to local z {approx} 0.04 compact galaxies in WIde field Nearby Galaxy clusters Survey (WINGS) clusters, and to z = 1.4-2 massive and passive galaxies found in the general field. If non-brightest cluster galaxies of all densities, morphologies, and spectral types are considered, the median size of EDisCS galaxies is only a factor 1.18 smaller than in WINGS. We show that for morphologically selected samples, the morphological evolution taking place in a significant fraction of galaxies during the last Gyr may introduce an apparent, spurious evolution of size with redshift, which is actually due to intrinsic differences in the selected samples. We conclude that the median mass-size relation of cluster galaxies does not evolve significantly from z {approx} 0.7 to z {approx} 0.04. In contrast, the masses and sizes of BCGs and galaxies with M {sub *}>4 x 10{sup 11} M {sub sun} have significantly increased by a factor of 2 and 4, respectively, confirming the results of a number of recent works on the subject. Our findings show that progenitor bias effects play an important role in the size-growth paradigm of massive and passive galaxies.

  10. SATELLITES AROUND MASSIVE GALAXIES SINCE z {approx} 2: CONFRONTING THE MILLENNIUM SIMULATION WITH OBSERVATIONS

    SciTech Connect

    Quilis, Vicent; Trujillo, Ignacio

    2012-06-20

    Minor merging has been postulated as the most likely evolutionary path to produce the increase in size and mass observed in the massive galaxies since z {approx} 2. In this Letter, we directly test this hypothesis, comparing the population of satellites around massive galaxies in cosmological simulations versus the observations. We use state-of-the-art, publically available, Millennium I and II simulations, and the associated semi-analytical galaxy catalogs to explore the time evolution of the fraction of massive galaxies that have satellites, the number of satellites per galaxy, the projected distance at which the satellites locate from the host galaxy, and the mass ratio between the host galaxies and their satellites. The three virtual galaxy catalogs considered here overproduce the fraction of galaxies with satellites by a factor ranging between 1.5 and 6 depending on the epoch, whereas the mean projected distance and ratio of the satellite mass over host mass are in closer agreement with data. The larger pull of satellites in the semi-analytical samples could suggest that the size evolution found in previous hydrodynamical simulations is an artifact due to the larger number of infalling satellites compared to the real universe. These results advise us to revise the physical ingredients implemented in the semi-analytical models in order to reconcile the observed and computed fraction of galaxies with satellites, and eventually, it would leave some room for other mechanisms explaining the galaxy size growth not related to the minor merging.

  11. First Eigenmode Transmission by High Efficient CSI Estimation for Multiuser Massive MIMO Using Millimeter Wave Bands.

    PubMed

    Maruta, Kazuki; Iwakuni, Tatsuhiko; Ohta, Atsushi; Arai, Takuto; Shirato, Yushi; Kurosaki, Satoshi; Iizuka, Masataka

    2016-01-01

    Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high order spatial multiplexing gain. Multiuser MIMO is also effective in further enhancing system capacity by multiplexing spatially de-correlated users. However, the transmission performance of multiuser MIMO is strongly degraded by channel time variation, which causes inter-user interference since null steering must be performed at the transmitter. This paper first addresses the effectiveness of multiuser massive MIMO transmission that exploits the first eigenmode for each user. In Line-of-Sight (LoS) dominant channel environments, the first eigenmode is chiefly formed by the LoS component, which is highly correlated with user movement. Therefore, the first eigenmode provided by a large antenna array can improve the robustness against the channel time variation. In addition, we propose a simplified beamforming scheme based on high efficient channel state information (CSI) estimation that extracts the LoS component. We also show that this approximate beamforming can achieve throughput performance comparable to that of the rigorous first eigenmode transmission. Our proposed multiuser massive MIMO scheme can open the door for practical millimeter wave communication with enhanced system capacity.

  12. Photon Bubbles in Young Massive Stars

    NASA Astrophysics Data System (ADS)

    Turner, N. J.; Yorke, H. W.; Socrates, A.; Blaes, O. M.

    2004-12-01

    Spectroscopic studies indicate that gas in the photospheres of young O stars moves at speeds up to the sound speed. We show, using two-dimensional radiation MHD calculations and results from a local linear analysis, that the motions may be due to photon bubble instability if young O stars have magnetic fields.

  13. Peering to the Heart of Massive Star Birth - IV. Surveying Across Evolution, Environment and the IMF

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan

    2014-10-01

    We propose to continue our Cycle 2 survey of MIR/FIR (10-40 micron) emission from massive protostars, utilizing the unique capabilities of SOFIA-FORCAST. We have demonstrated theoretically and observationally that 10-40 micron observations are crucial for defining the spectral energy distribution of massive protostars and thus the bolometric flux directed towards us. The 40 micron peak brightness is typically very close to the actual protostar's position, while at shorter wavelengths this is often not the case due to re-radiation via outflow cavities. SOFIA's relatively high angular resolution at 30-40 microns, i.e. ~3" compared to ~6" of Herschel at 70 microns, is thus important for disentangling massive star formation activity, especially that occurring in crowded regions. With source G35.2 we have also demonstrated SOFIA's ability to deliver high contrast imaging revealing fainter extended emission from the protostellar envelope that is impractical to observe from the ground at 10-20 microns. Combined with sophisticated radiative transfer modeling, analysis of this emission constrains the geometry of the outflow cavities, allowing more reliable measurement of the true bolometric luminosity and thus protostellar mass. Our goal is to continue to apply these techniques to a much larger sample of protostars, spanning a range of evolutionary and environmental states, from relatively isolated sources in Infrared Dark Clouds, to less extincted sources with compact (often jet-like) radio emission, to ultra-compact HII regions (where radio emission extends beyond MIR emission), to sources in crowded regions. We also include 10 intermediate-mass protostars to allow comparison with their more massive cousins. A typical observation will take ~60 minutes and the ~50 targeted fields of view will yield ~60 protostars: enough to begin to provide statistically significant samples in these different evolutionary and environmental states.

  14. A death due to perirenal hematoma complicating extracorporeal shockwave lithotripsy.

    PubMed

    Uemura, Koichi; Takahashi, Sayuri; Shintani-Ishida, Kaori; Nakajima, Makoto; Saka, Kanju; Yoshida, Ken-ichi

    2008-03-01

    Perirenal hematoma is an occasional complication of extracorporeal shockwave lithotripsy (ESWL) which does not usually require treatment. A 79-year-old woman died 23 h after ESWL. Forensic autopsy was performed to determine whether medical treatment contributed to her death. The cause of death was hemorrhagic shock due to massive hematoma from a ruptured small vein in the perirenal adipose capsule. No injury to other organs was found and the patient had neither coagulation abnormality nor venous disease. Perirenal hematoma can easily be diagnosed with abdominal sonography, if pain or symptoms of anemia develop. Doctors must be aware of the possibilities of severe renal hematomas after ESWL.

  15. Eta Carinae in the Context of the Most Massive Stars

    NASA Technical Reports Server (NTRS)

    Gull, Theodore R.; Damineli, Augusto

    2009-01-01

    Eta Car, with its historical outbursts, visible ejecta and massive, variable winds, continues to challenge both observers and modelers. In just the past five years over 100 papers have been published on this fascinating object. We now know it to be a massive binary system with a 5.54-year period. In January 2009, Car underwent one of its periodic low-states, associated with periastron passage of the two massive stars. This event was monitored by an intensive multi-wavelength campaign ranging from -rays to radio. A large amount of data was collected to test a number of evolving models including 3-D models of the massive interacting winds. August 2009 was an excellent time for observers and theorists to come together and review the accumulated studies, as have occurred in four meetings since 1998 devoted to Eta Car. Indeed, Car behaved both predictably and unpredictably during this most recent periastron, spurring timely discussions. Coincidently, WR140 also passed through periastron in early 2009. It, too, is a intensively studied massive interacting binary. Comparison of its properties, as well as the properties of other massive stars, with those of Eta Car is very instructive. These well-known examples of evolved massive binary systems provide many clues as to the fate of the most massive stars. What are the effects of the interacting winds, of individual stellar rotation, and of the circumstellar material on what we see as hypernovae/supernovae? We hope to learn. Topics discussed in this 1.5 day Joint Discussion were: Car: the 2009.0 event: Monitoring campaigns in X-rays, optical, radio, interferometry WR140 and HD5980: similarities and differences to Car LBVs and Eta Carinae: What is the relationship? Massive binary systems, wind interactions and 3-D modeling Shapes of the Homunculus & Little Homunculus: what do we learn about mass ejection? Massive stars: the connection to supernovae, hypernovae and gamma ray bursters Where do we go from here? (future

  16. Massive Black Hole Binary Mergers in Dynamical Galactic Environments

    NASA Astrophysics Data System (ADS)

    Kelley, Luke Zoltan; Blecha, Laura; Hernquist, Lars

    2016-10-01

    Gravitational Waves (GW) have now been detected from stellar-mass black hole binaries, and the first observations of GW from Massive Black Hole (MBH) Binaries are expected within the next decade. Pulsar Timing Arrays (PTA), which can measure the years long periods of GW from MBHB, have excluded many standard predictions for the amplitude of a stochastic GW Background (GWB). We use coevolved populations of MBH and galaxies from hydrodynamic, cosmological simulations ('Illustris') to calculate a predicted GWB. The most advanced predictions so far have included binary hardening mechanisms from individual environmental processes. We present the first calculation including all of the environmental mechanisms expected to be involved: dynamical friction, stellar `loss-cone' scattering, and viscous drag from a circumbinary disk. We find that MBH binary lifetimes are generally multiple gigayears, and only a fraction coalesce by redshift zero. For a variety of parameters, we find all GWB amplitudes to be below the most stringent PTA upper limit of A_yr^{-1} ≈ 10^{-15}. Our fairly conservative fiducial model predicts an amplitude of A_yr^{-1} ≈ 0.4× 10^{-15}. At lower frequencies, we find A_{0.1 yr^{-1} ≈ 1.5× 10^{-15} with spectral indices between -0.4 and -0.6-significantly flatter than the canonical value of -2/3 due to purely GW-driven evolution. Typical MBHB driving the GWB signal come from redshifts around 0.3, with total masses of a few times 109 M⊙, and in host galaxies with very large stellar masses. Even without GWB detections, our results can be connected to observations of dual AGN to constrain binary evolution.

  17. A faint galaxy redshift survey behind massive clusters

    SciTech Connect

    Frye, Brenda

    1999-12-01

    This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of {approximately}20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

  18. JET FORMATION FROM MASSIVE YOUNG STARS: MAGNETOHYDRODYNAMICS VERSUS RADIATION PRESSURE

    SciTech Connect

    Vaidya, Bhargav; Porth, Oliver; Fendt, Christian; Beuther, Henrik E-mail: fendt@mpia.de

    2011-11-20

    Observations indicate that outflows from massive young stars are more collimated during their early evolution compared to later stages. Our paper investigates various physical processes that impact the outflow dynamics, i.e., its acceleration and collimation. We perform axisymmetric magnetohydrodynamic (MHD) simulations particularly considering the radiation pressure exerted by the star and the disk. We have modified the PLUTO code to include radiative forces in the line-driving approximation. We launch the outflow from the innermost disk region (r < 50 AU) by magnetocentrifugal acceleration. In order to disentangle MHD effects from radiative forces, we start the simulation in pure MHD and later switch on the radiation force. We perform a parameter study considering different stellar masses (thus luminosity), magnetic flux, and line-force strength. For our reference simulation-assuming a 30 M{sub Sun} star-we find substantial de-collimation of 35% due to radiation forces. The opening angle increases from 20 Degree-Sign to 32 Degree-Sign for stellar masses from 20 M{sub Sun} to 60 M{sub Sun }. A small change in the line-force parameter {alpha} from 0.60 to 0.55 changes the opening angle by {approx}8 Degree-Sign . We find that it is mainly the stellar radiation that affects the jet dynamics. Unless the disk extends very close to the star, its force is too small to have much impact. Essentially, our parameter runs with different stellar masses can be understood as a proxy for the time evolution of the star-outflow system. Thus, we have shown that when the stellar mass (thus luminosity) increases with age, the outflows become less collimated.

  19. Microevolution of Cryptococcus neoformans driven by massive tandem gene amplification.

    PubMed

    Chow, Eve W L; Morrow, Carl A; Djordjevic, Julianne T; Wood, Ian A; Fraser, James A

    2012-08-01

    The subtelomeric regions of organisms ranging from protists to fungi undergo a much higher rate of rearrangement than is observed in the rest of the genome. While characterizing these ~40-kb regions of the human fungal pathogen Cryptococcus neoformans, we have identified a recent gene amplification event near the right telomere of chromosome 3 that involves a gene encoding an arsenite efflux transporter (ARR3). The 3,177-bp amplicon exists in a tandem array of 2-15 copies and is present exclusively in strains with the C. neoformans var. grubii subclade VNI A5 MLST profile. Strains bearing the amplification display dramatically enhanced resistance to arsenite that correlates with the copy number of the repeat; the origin of increased resistance was verified as transport-related by functional complementation of an arsenite transporter mutant of Saccharomyces cerevisiae. Subsequent experimental evolution in the presence of increasing concentrations of arsenite yielded highly resistant strains with the ARR3 amplicon further amplified to over 50 copies, accounting for up to ~1% of the whole genome and making the copy number of this repeat as high as that seen for the ribosomal DNA. The example described here therefore represents a rare evolutionary intermediate-an array that is currently in a state of dynamic flux, in dramatic contrast to relatively common, static relics of past tandem duplications that are unable to further amplify due to nucleotide divergence. Beyond identifying and engineering fungal isolates that are highly resistant to arsenite and describing the first reported instance of microevolution via massive gene amplification in C. neoformans, these results suggest that adaptation through gene amplification may be an important mechanism that C. neoformans employs in response to environmental stresses, perhaps including those encountered during infection. More importantly, the ARR3 array will serve as an ideal model for further molecular genetic analyses of

  20. A Dark Spot on a Massive White Dwarf

    NASA Astrophysics Data System (ADS)

    Kilic, Mukremin; Gianninas, Alexandros; Bell, Keaton J.; Curd, Brandon; Brown, Warren R.; Hermes, J. J.; Dufour, Patrick; Wisniewski, John P.; Winget, D. E.; Winget, K. I.

    2015-12-01

    We present the serendipitous discovery of eclipse-like events around the massive white dwarf SDSS J152934.98+292801.9 (hereafter J1529+2928). We selected J1529+2928 for time-series photometry based on its spectroscopic temperature and surface gravity, which place it near the ZZ Ceti instability strip. Instead of pulsations, we detect photometric dips from this white dwarf every 38 minutes. Follow-up optical spectroscopy observations with Gemini reveal no significant radial velocity variations, ruling out stellar and brown dwarf companions. A disintegrating planet around this white dwarf cannot explain the observed light curves in different filters. Given the short period, the source of the photometric dips must be a dark spot that comes into view every 38 minutes due to the rotation of the white dwarf. Our optical spectroscopy does not show any evidence of Zeeman splitting of the Balmer lines, limiting the magnetic field strength to B < 70 kG. Since up to 15% of white dwarfs display kG magnetic fields, such eclipse-like events should be common around white dwarfs. We discuss the potential implications of this discovery on transient surveys targeting white dwarfs, like the K2 mission and the Large Synoptic Survey Telescope. This work is based on observations obtained at the Gemini Observatory, McDonald Observatory, and the Apache Point Observatory 3.5-m telescope. The latter is owned and operated by the Astrophysical Research Consortium. Gemini Observatory is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  1. SELF-REGULATED SHOCKS IN MASSIVE STAR BINARY SYSTEMS

    SciTech Connect

    Parkin, E. R.; Sim, S. A. E-mail: s.sim@qub.ac.uk

    2013-04-20

    In an early-type, massive star binary system, X-ray bright shocks result from the powerful collision of stellar winds driven by radiation pressure on spectral line transitions. We examine the influence of the X-rays from the wind-wind collision shocks on the radiative driving of the stellar winds using steady-state models that include a parameterized line force with X-ray ionization dependence. Our primary result is that X-ray radiation from the shocks inhibits wind acceleration and can lead to a lower pre-shock velocity, and a correspondingly lower shocked plasma temperature, yet the intrinsic X-ray luminosity of the shocks, L{sub X}, remains largely unaltered, with the exception of a modest increase at small binary separations. Due to the feedback loop between the ionizing X-rays from the shocks and the wind driving, we term this scenario as self-regulated shocks. This effect is found to greatly increase the range of binary separations at which a wind-photosphere collision is likely to occur in systems where the momenta of the two winds are significantly different. Furthermore, the excessive levels of X-ray ionization close to the shocks completely suppress the line force, and we suggest that this may render radiative braking less effective. Comparisons of model results against observations reveal reasonable agreement in terms of log (L{sub X}/L{sub bol}). The inclusion of self-regulated shocks improves the match for kT values in roughly equal wind momenta systems, but there is a systematic offset for systems with unequal wind momenta (if considered to be a wind-photosphere collision).

  2. MASSIVE STARS IN THE Cl 1813-178 CLUSTER: AN EPISODE OF MASSIVE STAR FORMATION IN THE W33 COMPLEX

    SciTech Connect

    Messineo, Maria; Davies, Ben; Figer, Donald F.; Trombley, Christine; Kudritzki, R. P.; Valenti, Elena; Najarro, F.; Michael Rich, R.

    2011-05-20

    Young massive (M > 10{sup 4} M{sub sun}) stellar clusters are a good laboratory to study the evolution of massive stars. Only a dozen of such clusters are known in the Galaxy. Here, we report about a new young massive stellar cluster in the Milky Way. Near-infrared medium-resolution spectroscopy with UIST on the UKIRT telescope and NIRSPEC on the Keck telescope, and X-ray observations with the Chandra and XMM satellites, of the Cl 1813-178 cluster confirm a large number of massive stars. We detected 1 red supergiant, 2 Wolf-Rayet stars, 1 candidate luminous blue variable, 2 OIf, and 19 OB stars. Among the latter, twelve are likely supergiants, four giants, and the faintest three dwarf stars. We detected post-main-sequence stars with masses between 25 and 100 M{sub sun}. A population with age of 4-4.5 Myr and a mass of {approx}10, 000 M{sub sun} can reproduce such a mixture of massive evolved stars. This massive stellar cluster is the first detection of a cluster in the W33 complex. Six supernova remnants and several other candidate clusters are found in the direction of the same complex.

  3. Intestinal pseudo-obstruction due to amyloidosis of the colon in association with an intestinal plasmacytoma.

    PubMed Central

    Nicholl, D.; Jones, T.

    1991-01-01

    A case of large bowel pseudo-obstruction due to colonic amyloidosis associated with an intestinal plasmacytoma is described. The association of an intestinal plasmacytoma with massive local amyloid deposition has not to our knowledge been previously reported. Images Figure 1 Figure 2 PMID:1800969

  4. Zoning Issues and Area of Interest Management in Massively Multiplayer Online Games

    NASA Astrophysics Data System (ADS)

    Ahmed, Dewan Tanvir; Shirmohammadi, Shervin

    Game is a way of entertainment, a means for excitement, fun and socialization. Online games have achieved popularity due to increasing broadband adoption among consumers. Relatively cheap bandwidth Internet connections allow large number of players to play together. Since the introduction of Network Virtual Environment (NVE) in 1980s for military simulation, many interesting applications have been evolved over the past few decades. Massively multiplayer online (role-playing) game, MMOG or MMORPG, is a new genre of online games that has emerged with the introduction of Ultima since 1997. It is a kind of online computer game with the participation of hundreds of thousands of players in a virtual world.

  5. Spontaneous subdural hematoma of the thoracolumbar region with massive recurrent bleed

    PubMed Central

    Cincu, Rafael; de Asis Lorente, Francisco; Rivero, David; Eiras, José; Ara, José Ramón

    2009-01-01

    Spinal subdural hematoma is a rare disorder and can be caused by abnormalities of coagulation, blood dyscrasias, lumbar puncture, trauma, underlying neoplasm, and arteriovenous malformation. We discuss an unusual case of an elderly woman who presented with spontaneous spinal subdural hematoma and developed massive rebleeding on the third day following initial evacuation of hematoma. This case illustrates that a patient with routine normal coagulation profile and adequate hemostasis can still harbor platelet dysfunction (in present case due to polycythemia) and later on can manifest as rebleeding and neurological deterioration. PMID:19838395

  6. Massive Localized Lymphedema in the Morbidly Obese Patient: A Clinical Entity Mimicking Lymphosarcoma.

    PubMed

    Kotidis, Efstathios; Cepaityte, Dainora; Petrakis, Georgios; Sapalidis, Konstantinos; Kanellos, Ioannis

    2015-09-01

    Massive localized lymphedema (MLL) is a rare benign soft tissue lesion that develops in morbidly obese patients, most commonly on the medial thigh (though other locations have also been described). The cause of MLL remains unknown, but the common denominator in all reported cases is obesity. The diagnosis of MLL is usually made based on clinical history and presentation but it is believed to be underdiagnosed due to a lack of awareness of this distinct entity. When left untreated, MLL can degenerate into angiosarcoma. This report describes a case of MLL of the right lower abdominal wall in an obese 61-year-old female (BMI = 42 kg/m(2)). PMID:26367787

  7. Trace element content of gossans at four mines in the West Shasta massive sulfide district.

    USGS Publications Warehouse

    Sanzolone, R.F.; Domenico, J.A.

    1985-01-01

    Paired analyses of the spongy whole-rock gossan and its botryoidal crust ("chipped rock rind') show little differences, whereas duplicate samples of each at individual sites show such extreme differences as to preclude the use of the data in areal mapping. Gossans from disseminated sulphides have lower and less variable trace-element contents than gossans from massive sulphides, due in part to dilution by rock silicates. Computer reduction of the data by a regionalizing algorithm enables determination of pattern differences among the four mines.-G.J.N.

  8. THE WMAP HAZE FROM THE GALACTIC CENTER REGION DUE TO MASSIVE STAR EXPLOSIONS AND A REDUCED COSMIC RAY SCALE HEIGHT

    SciTech Connect

    Biermann, Peter L.; Becker, Julia K.; Caceres, Gabriel; Meli, Athina; Seo, Eun-Suk; Stanev, Todor

    2010-02-10

    One important prediction of acceleration of particles in the supernova caused shock in the magnetic wind of exploding Wolf-Rayet and red supergiant stars is the production of an energetic particle component with an E {sup -2} spectrum at a level on the order of 1% of the full cosmic ray electron population. After allowing for transport effects, so steepening the spectrum to E {sup -7/3}, this component as cosmic ray electrons readily explains the WMAP haze from the Galactic center region in spectrum, intensity, and radial profile; this requires the diffusion timescale for cosmic rays in the Galactic center region to be much shorter than in the solar neighborhood: the energy for cosmic ray electrons at the transition between diffusion dominance and loss dominance is shifted to considerably higher particle energy. We predict that more precise observations will find a radio spectrum of {nu}{sup -2/3}, at higher frequencies {nu}{sup -1}, and at yet higher frequencies finally {nu}{sup -3/2}.

  9. Interposition Porcine Acellular Dermal Matrix Xenograft Successful Alternative in Treatment for Massive Rotator Cuff

    PubMed Central

    Neumann, Julie; Zgonis, Miltiadis H.; Reay, Kathleen Dolores; Mayer, Stephanie W.; Boggess, Blake; Toth, Alison P.

    2016-01-01

    improved from 133.2° to 157.9° (P=0.003), 51.56° to 64.25° (P=0.001), and 49.8° to 74.0° (P<0.001), respectively. Manual strength (10 point scale) in supraspinatus and infraspinatus increased from 7.3 to 8.9 (P<0.001) and 7.4 to 9.4 (P<0.001), respectively. Using a dynamometer, supraspinatus quantitative strength was a mean of 68.6N and infraspinatus quantitative strength was a mean of 50.6N. Ultrasound evaluation of repairs showed 33 (89.1%) to be fully intact, three (8.1%) had partial tears, and one repair (2.7%) was not intact. The one patient whose repair was not intact by ultrasound was a revision repair. No infections, evidence of inflammatory reaction, tissue rejection, or major adverse outcomes were identified. Three patients underwent ipsilateral shoulder surgery for lysis of adhesions due to post-operative decreased ROM during the follow-up period. Conclusion: Following repair of massive rotator cuff tears with interposition porcine acellular dermal matrix xenografts, patients had significant improvement in pain, range of motion, strength and reported good subjective function based on M-ASES and SF-12 scores. The repair was completely intact in 89% of patients, a vast improvement compared with results reported for primary repairs of massive rotator cuff tears. Tissue grafts such as the porcine acellular graft used in our study hold great promise in the treatment of massive, retracted rotator cuff tears.

  10. Lorentz constraints on massive three-point amplitudes

    NASA Astrophysics Data System (ADS)

    Conde, Eduardo; Marzolla, Andrea

    2016-09-01

    Using the helicity-spinor language we explore the non-perturbative constraints that Lorentz symmetry imposes on three-point amplitudes where the asymptotic states can be massive. As it is well known, in the case of only massless states the three-point amplitude is fixed up to a coupling constant by these constraints plus some physical requirements. We find that a similar statement can be made when some of the particles have mass. We derive the generic functional form of the three-point amplitude by virtue of Lorentz symmetry, which displays several functional structures accompanied by arbitrary constants. These constants can be related to the coupling constants of the theory, but in an unambiguous fashion only in the case of one massive particle. Constraints on these constants are obtained by imposing that in the UV limit the massive amplitude matches the massless one. In particular, there is a certain Lorentz frame, which corresponds to projecting all the massive momenta along the same null momentum, where the three-point massive amplitude is fully fixed, and has a universal form.

  11. Globular cluster abundance anomalies and the massive binary polluter scenario

    NASA Astrophysics Data System (ADS)

    Szécsi, Dorottya; González-Jímenez, Nicolas; Langer, Norbert

    2014-09-01

    Observations of globular cluster stars indicate that their material has been polluted with the nucleosynthetically processed matter of a previous generation of massive stars, but not with supernova products. The nature of the polluter is still being debated: either hot-bottom-burning AGB stars or rapidly rotating massive stars could be responsible, although both scenarios face major challenges to explain the observed abundance patterns and require fine-tuning of the most relevant parameters. An alternative scenario involves massive binary polluters: nucleosynthetically processed gas is expelled during highly non-conservative mass transfer in interacting massive binary systems. It has been shown that such systems could return enough material to form a chemically enriched second generation. However, for a detailed comparison of the chemical predictions of this scenario, binary models for a range of masses and orbital periods are needed. We have carried out detailed calculations of interacting massive binaries with various mass ratios and orbital periods. The evolution of these systems is presented. Constraints on the initial parameters are analyzed, observed abundances are compared to theoretical yields, and advantages and disadvantages of this scenario are discussed.

  12. Initiation of Massive Landsliding through Progressive Strength Reduction in Volcanoes

    NASA Astrophysics Data System (ADS)

    Reid, M. E.; Keith, T. C.; Kayen, R. E.; Iverson, N. R.; Iverson, R. M.; Brien, D. L.

    2011-12-01

    Landslides that sculpt deeply into volcano edifices can be extremely large. For example, the 1980 collapse of Mount St. Helens (MSH) volcano generated a 2.8 km3 debris-avalanche deposit from a series of massive retrogressive failures. Rock shear strength plays a fundamental role in such landsliding, yet pertinent data from modern volcano collapse surfaces are rare. The collapse crater at MSH affords access to rocks directly from the failure surface of the1980 massive landslide. We used a combination of field observations, laboratory strength tests designed to mimic conditions in the pre-collapse edifice, and quasi-3D slope-stability analyses to investigate the effects of progressive strength reduction, caused by pre-collapse deformation, on the instability of the volcano's edifice. Within the MSH crater, we observed that the basal shear zone from the outermost initial landslide block (Block I) of the 1980 failure formed primarily in pervasively shattered older dacitic dome rocks; shearing was not localized in sloping volcanic strata or in weak, hydrothermally altered rocks. We collected relatively undisturbed tube samples and disturbed bulk samples of the shattered dacite from near the slip surface of Block I. Using a triaxial testing device, equipped with high-pressure components to mimic overburden stresses in the pre-collapse edifice, we determined the quasi-static drained shear strength of the undisturbed samples. These tests indicated a peak angle of internal friction, φ, of 35° and a residual φ (after undergoing axial strain up to 20%) of 29°. We also determined residual shear strength using a specially constructed large-volume ring-shear apparatus that imposed large quasi-static shear strains exceeding 100%. These tests yielded a similar residual strength, with φ of 27°. Prior to its catastrophic collapse in 1980, the MSH edifice was deformed northward tens of meters by an intruding cryptodome, which likely caused shearing along a summit fault and

  13. Space-time philosophy reconstructed via massive Nordström scalar gravities? Laws vs. geometry, conventionality, and underdetermination

    NASA Astrophysics Data System (ADS)

    Pitts, J. Brian

    2016-02-01

    What if gravity satisfied the Klein-Gordon equation? Both particle physics from the 1920-30s and the 1890s Neumann-Seeliger modification of Newtonian gravity with exponential decay suggest considering a "graviton mass term" for gravity, which is algebraic in the potential. Unlike Nordström's "massless" theory, massive scalar gravity is strictly special relativistic in the sense of being invariant under the Poincaré group but not the 15-parameter Bateman-Cunningham conformal group. It therefore exhibits the whole of Minkowski space-time structure, albeit only indirectly concerning volumes. Massive scalar gravity is plausible in terms of relativistic field theory, while violating most interesting versions of Einstein's principles of general covariance, general relativity, equivalence, and Mach. Geometry is a poor guide to understanding massive scalar gravity(s): matter sees a conformally flat metric due to universal coupling, but gravity also sees the rest of the flat metric (barely or on long distances) in the mass term. What is the 'true' geometry, one might wonder, in line with Poincaré's modal conventionality argument? Infinitely many theories exhibit this bimetric 'geometry,' all with the total stress-energy's trace as source; thus geometry does not explain the field equations. The irrelevance of the Ehlers-Pirani-Schild construction to a critique of conventionalism becomes evident when multi-geometry theories are contemplated. Much as Seeliger envisaged, the smooth massless limit indicates underdetermination of theories by data between massless and massive scalar gravities-indeed an unconceived alternative. At least one version easily could have been developed before General Relativity; it then would have motivated thinking of Einstein's equations along the lines of Einstein's newly re-appreciated "physical strategy" and particle physics and would have suggested a rivalry from massive spin 2 variants of General Relativity (massless spin 2, Pauli and Fierz

  14. Waveforms in massive gravity and neutralization of giant black hole ringings

    NASA Astrophysics Data System (ADS)

    Décanini, Yves; Folacci, Antoine; Ould El Hadj, Mohamed

    2016-06-01

    A distorted black hole radiates gravitational waves in order to settle down in a smoother geometry. During that relaxation phase, a characteristic damped ringing is generated. It can be theoretically constructed from both the black hole quasinormal frequencies (which govern its oscillating behavior and its decay) and the associated excitation factors (which determine intrinsically its amplitude) by carefully taking into account the source of the distortion. In the framework of massive gravity, the excitation factors of the Schwarzschild black hole have an unexpected strong resonant behavior which, theoretically, could lead to giant and slowly decaying ringings. If massive gravity is relevant to physics, one can hope to observe these extraordinary ringings by using the next generations of gravitational wave detectors. Indeed, they could be generated by supermassive black holes if the graviton mass is not too small. In fact, by focusing on the odd-parity ℓ=1 mode of the Fierz-Pauli field, we shall show here that such ringings are neutralized in waveforms due to (i) the excitation of the quasibound states of the black hole and (ii) the evanescent nature of the particular partial modes which could excite the concerned quasinormal modes. Despite this, with observational consequences in mind, it is interesting to note that the waveform amplitude is nevertheless rather pronounced and slowly decaying (this effect is now due to the long-lived quasibound states). It is worth noting also that, for very low values of the graviton mass (corresponding to the weak instability regime for the black hole), the waveform is now very clean and dominated by an ordinary ringing which could be used as a signature of massive gravity.

  15. Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection

    NASA Astrophysics Data System (ADS)

    Sana, H.; Le Bouquin, J.-B.; Lacour, S.; Berger, J.-P.; Duvert, G.; Gauchet, L.; Norris, B.; Olofsson, J.; Pickel, D.; Zins, G.; Absil, O.; de Koter, A.; Kratter, K.; Schnurr, O.; Zinnecker, H.

    2014-11-01

    Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 milliarcsec (mas) remain mostly unknown due to intrinsic observational limitations. At a typical distance of 2 kpc, this corresponds to projected physical separations of 2-200 AU. The Southern MAssive Stars at High angular resolution survey (SMaSH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/Sparse Aperture Masking (SAM), probing the separation ranges 1-45 and 30-250 mas and brightness contrasts of ΔH < 4 and ΔH < 5, respectively. Taking advantage of NACO's field of view, we further uniformly searched for visual companions in an 8'' radius down to ΔH = 8. This paper describes observations and data analysis, reports the discovery of almost 200 new companions in the separation range from 1 mas to 8'' and presents a catalog of detections, including the first resolved measurements of over a dozen known long-period spectroscopic binaries. Excluding known runaway stars for which no companions are detected, 96 objects in our main sample (δ < 0° H < 7.5) were observed both with PIONIER and NACO/SAM. The fraction of these stars with at least one resolved companion within 200 mas is 0.53. Accounting for known but unresolved spectroscopic or eclipsing companions, the multiplicity fraction at separation ρ < 8'' increases to f m = 0.91 ± 0.03. The fraction of luminosity class V stars that have a bound companion reaches 100% at 30 mas while their average number of physically connected companions within 8'' is f c = 2.2 ± 0.3. This demonstrates that massive stars form nearly exclusively in multiple systems. The nine non-thermal radio emitters observed by SMaSH+ are all resolved, including the newly

  16. SOUTHERN MASSIVE STARS AT HIGH ANGULAR RESOLUTION: OBSERVATIONAL CAMPAIGN AND COMPANION DETECTION

    SciTech Connect

    Sana, H.; Lacour, S.; Gauchet, L.; Pickel, D.; Berger, J.-P.; Norris, B.; Olofsson, J.; Absil, O.; De Koter, A.; Kratter, K.; Schnurr, O.; Zinnecker, H.

    2014-11-01

    Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 milliarcsec (mas) remain mostly unknown due to intrinsic observational limitations. At a typical distance of 2 kpc, this corresponds to projected physical separations of 2-200 AU. The Southern MAssive Stars at High angular resolution survey (SMaSH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/Sparse Aperture Masking (SAM), probing the separation ranges 1-45 and 30-250 mas and brightness contrasts of ΔH < 4 and ΔH < 5, respectively. Taking advantage of NACO's field of view, we further uniformly searched for visual companions in an 8'' radius down to ΔH = 8. This paper describes observations and data analysis, reports the discovery of almost 200 new companions in the separation range from 1 mas to 8'' and presents a catalog of detections, including the first resolved measurements of over a dozen known long-period spectroscopic binaries. Excluding known runaway stars for which no companions are detected, 96 objects in our main sample (δ < 0°; H < 7.5) were observed both with PIONIER and NACO/SAM. The fraction of these stars with at least one resolved companion within 200 mas is 0.53. Accounting for known but unresolved spectroscopic or eclipsing companions, the multiplicity fraction at separation ρ < 8'' increases to f {sub m} = 0.91 ± 0.03. The fraction of luminosity class V stars that have a bound companion reaches 100% at 30 mas while their average number of physically connected companions within 8'' is f {sub c} = 2.2 ± 0.3. This demonstrates that massive stars form nearly exclusively in multiple systems. The nine non-thermal radio emitters observed by SMaSH+ are all resolved

  17. YOUNG STELLAR GROUPS AND THEIR MOST MASSIVE STARS

    SciTech Connect

    Kirk, Helen; Myers, Philip C.

    2011-02-01

    We analyze the masses and spatial distributions of 14 young stellar groups in Taurus, Lupus3, ChaI, and IC348. These nearby groups, which typically contain 20-40 members, have membership catalogs complete to {approx}0.02 M{sub sun}, and are sufficiently young that their locations should be similar to where they formed. These groups show five properties seen in clusters having many more stars and much greater surface density of stars: (1) a broad range of masses, (2) a concentration of the most massive star toward the center of the group, (3) an association of the most massive star with a high surface density of lower mass stars, (4) a correlation of the mass of the most massive star with the total mass of the group, and (5) the distribution of a large fraction of the mass in a small fraction of the stars.

  18. Massive gravitational waves in Chern-Simons modified gravity

    SciTech Connect

    Myung, Yun Soo; Moon, Taeyoon E-mail: tymoon@inje.ac.kr

    2014-10-01

    We consider the nondynamical Chern-Simons (nCS) modified gravity, which is regarded as a parity-odd theory of massive gravity in four dimensions. We first find polarization modes of gravitational waves for θ=x/μ in nCS modified gravity by using the Newman-Penrose formalism where the null complex tetrad is necessary to specify gravitational waves. We show that in the Newman–Penrose formalism, the number of polarization modes is one in addition to an unspecified Ψ{sub 4}, implying three degrees of freedom for θ=x/μ. This compares with two for a canonical embedding of θ=t/μ. Also, if one introduces the Ricci tensor formalism to describe a massive graviton arising from the nCS modified gravity, one finds one massive mode after making second-order wave equations, which is compared to five found from the parity-even Einstein–Weyl gravity.

  19. Massive Stars in Colliding Wind Systems: the GLAST Perspective

    SciTech Connect

    Reimer, Anita; Reimer, Olaf; /Stanford U., HEPL /KIPAC, Menlo Park

    2011-11-29

    Colliding winds of massive stars in binary systems are considered as candidate sites of high-energy non-thermal photon emission. They are already among the suggested counterparts for a few individual unidentified EGRET sources, but may constitute a detectable source population for the GLAST observatory. The present work investigates such population study of massive colliding wind systems at high-energy gamma-rays. Based on the recent detailed model (Reimer et al. 2006) for non-thermal photon production in prime candidate systems, we unveil the expected characteristics of this source class in the observables accessible at LAT energies. Combining the broadband emission model with the presently cataloged distribution of such systems and their individual parameters allows us to conclude on the expected maximum number of LAT-detections among massive stars in colliding wind binary systems.

  20. Massively parallel neural encoding and decoding of visual stimuli.

    PubMed

    Lazar, Aurel A; Zhou, Yiyin

    2012-08-01

    The massively parallel nature of video Time Encoding Machines (TEMs) calls for scalable, massively parallel decoders that are implemented with neural components. The current generation of decoding algorithms is based on computing the pseudo-inverse of a matrix and does not satisfy these requirements. Here we consider video TEMs with an architecture built using Gabor receptive fields and a population of Integrate-and-Fire neurons. We show how to build a scalable architecture for video Time Decoding Machines using recurrent neural networks. Furthermore, we extend our architecture to handle the reconstruction of visual stimuli encoded with massively parallel video TEMs having neurons with random thresholds. Finally, we discuss in detail our algorithms and demonstrate their scalability and performance on a large scale GPU cluster. PMID:22397951

  1. Massive vectors and loop observables: the g - 2 case

    NASA Astrophysics Data System (ADS)

    Biggio, Carla; Bordone, Marzia; Di Luzio, Luca; Ridolfi, Giovanni

    2016-10-01

    We discuss the use of massive vectors for the interpretation of some recent experimental anomalies, with special attention to the muon g-2. We restrict our discussion to the case where the massive vector is embedded into a spontaneously broken gauge symmetry, so that the predictions are not affected by the choice of an arbitrary energy cut-off. Extended gauge symmetries, however, typically impose strong constraints on the mass of the new vector boson and for the muon g - 2 they basically rule out, barring the case of abelian gauge extensions, the explanation of the discrepancy in terms of a single vector extension of the standard model. We finally comment on the use of massive vectors for B-meson decay and di-photon anomalies.

  2. Gamma Ray Emission from Chaotic Winds of Massive Stars

    NASA Technical Reports Server (NTRS)

    White, Richard L.

    2000-01-01

    The purpose of this proposal was to search for gamma-ray emission from the winds of hot, massive stars. According to our theoretical calculations, shocks in the winds of massive stars accelerate particles to high energies. The high-energy particles emit synchrotron radio emission (observed by ground-based radio telescopes) and high-energy gamma-ray emission that we predicted should be detectable by the EGRET instrument on the Compton Gamma Ray Observatory between 100 MeV and a few GeV. We obtained EGRET from phases 1, 2, and 3 of the Cygnus OB2 association, a cluster of massive, young stars, to search for this gamma-ray emission. The data products and analysis show a source consistent with the position of Cyg OB2 with approximately the predicted count rate and spectrum.

  3. Vainshtein mechanism in massive gravity nonlinear sigma models

    NASA Astrophysics Data System (ADS)

    Aoki, Katsuki; Mizuno, Shuntaro

    2016-09-01

    We study the stability of the Vainshtein screening solution of massive gravity/bigravity based on the massive nonlinear sigma model as the effective action inside the Vainshtein radius. The effective action is obtained by taking the Λ2 decoupling limit around a curved spacetime. First we derive a general consequence that any Ricci flat Vainshtein screening solution is unstable when we take into account the excitation of the scalar graviton only. This instability suggests that the nonlinear excitation of the scalar graviton is not sufficient to obtain a successful Vainshtein screening in massive gravity/bigravity. Then to see the role of the excitation of the vector graviton, we study perturbations around the static and spherically symmetric solution obtained in bigravity explicitly. As a result, we find that linear excitations of the vector graviton cannot be helpful and the solution still suffers from a ghost and/or a gradient instability for any parameters of the theory for this background.

  4. Light element production by low energy nuclei from massive stars

    NASA Technical Reports Server (NTRS)

    Vangioni-Flam, E.; Casse, M.; Ramaty, R.

    1997-01-01

    The Orion complex is a source of gamma rays attributed to the de-excitation of fast carbon and oxygen nuclei excited through interactions with ambient hydrogen and helium. This has consequences for the production and evolution of light isotopes in the Galaxy, as massive stars appear as prolific sources of C-O rich low energy nuclei. The different stages of massive star evolution are considered in relation to the acceleration of nuclei to moderate energies. It is concluded that the low energy nuclear component originating from massive stars plays a larger role than the usual Galactic cosmic rays in shaping the evolution of Li-6, Be-9, B-10 and B-11, especially in the early Galactic evolution. The enhancement of the B-11/B-10 ratio observed in meteorites and in the interstellar medium is attributed to the interaction of low energy carbon nuclei with ambient H and to a lesser degree, to neutrino spallation.

  5. Massive postoperative pulmonary embolism in a young woman using oral contraceptives: the value of a preoperative anesthetic consult.

    PubMed

    Amar, S; Van Boven, M; Rooijakkers, H; Momeni, M

    2014-01-01

    We describe the case of a woman with a history of active tabagism and on the oral contraceptive Yasmin, presenting in the Post-Anesthesia Care Unit (PACU) with a cardiac arrest due to massive pulmonary embolism following transforaminal lumbar interbody fusion surgery. The patient had preoperatively several risk factors for deep venous thrombosis. This case-report emphasizes the value of a preoperative anesthetic visit and eventual temporary cessation of certain oral contraceptives in specific cases. PMID:25223166

  6. Massive Charcot spinal disease deformity in a patient presenting with increasing abdominal girth and discomfort. Case report.

    PubMed

    Bishop, Frank S; Dailey, Andrew T; Schmidt, Meic H

    2010-03-01

    Charcot spinal disease is a destructive degenerative process involving the vertebrae and surrounding discs, resulting from repetitive microtrauma in patients who have decreased joint protective mechanisms due to loss of deep pain and proprioceptive sensation. The typical presentation of the disease is back pain and progressive spinal instability and deformity. The authors report an unusual case of massive Charcot spinal disease deformity in a patient presenting with increasing abdominal girth and discomfort.

  7. Early massive clusters and the bouncing coupled dark energy

    NASA Astrophysics Data System (ADS)

    Baldi, Marco

    2012-02-01

    The abundance of the most massive objects in the Universe at different epochs is a very sensitive probe of the cosmic background evolution and of the growth history of density perturbations, and could provide a powerful tool to distinguish between a cosmological constant and a dynamical dark energy field. In particular, the recent detection of very massive clusters of galaxies at high redshifts has attracted significant interest as a possible indication of a failure of the standard Λ cold dark matter model. Several attempts have been made in order to explain such detections in the context of non-Gaussian scenarios or interacting dark energy models, showing that both these alternative cosmologies predict an enhanced number density of massive clusters at high redshifts, possibly alleviating the tension. However, all the models proposed so far also overpredict the abundance of massive clusters at the present epoch, and are therefore in contrast with observational bounds on the low-redshift halo mass function. In this paper we present for the first time a new class of interacting dark energy models that simultaneously account for an enhanced number density of massive clusters at high redshifts and for both the standard cluster abundance at the present time and the standard power spectrum normalization at cosmic microwave background (CMB). The key feature of this new class of models is the 'bounce' of the dark energy scalar field on the cosmological constant barrier at relatively recent epochs. We present the background and linear perturbations evolution of the model, showing that the standard amplitude of density perturbations is recovered both at CMB and at the present time, and we demonstrate by means of large N-body simulations that our scenario predicts an enhanced number of massive clusters at high redshifts without affecting the present halo abundance. Such behaviour could not arise in non-Gaussian models, and is therefore a characteristic feature of the

  8. [Ratio of erythrocyte and plasma in massive blood transfusion].

    PubMed

    Wen, Xian-Hui; Liu, Feng-Xia; Zhang, Jun-Hua; Gui, Rong

    2014-06-01

    This study was purposed to explore the suitable ratio between fresh frozen plasma and erythrocyte by retrospective analysis of coagulation in patients with massive blood transfusion. The clinical data of 151 cases with massive blood transfusion from January 2011 to January 2013 were analyzed retrospectively. According to coagulation, patients were divided into coagulation normal group (138 cases) and coagulation dysfunction group (13 cases). Based on the ratio of 1:1 of fresh frozen plasma and erythrocyte, the patients were divided into high plasma group(2:1), medium plasma group (1:1) and low plasma (<1:1) subgroups. Coagulation was detected before and after 24 h of massive blood transfusion. The results showed that prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT) were prolonged, fibrinogen (FIB) level decreased significantly (all P < 0.05) in the low plasma subgroup of coagulation normal group after massive blood transfusion 24 h; the high plasma and the medium plasma group of coagulation normal group had no significant changes in coagulation (P > 0.05); prothrombin time, activated partial thromboplastin time, thrombin time and fibrinogen level in the medium plasma and low plasma subgroup of coagulation dysfunction group after massive transfusion was still in abnormal levels (P > 0.05), coagulation function in high plasma subgroup was improved significantly (P < 0.05). It is concluded that the ratio of plasma to erythrocyte should be adjusted according to the patient's coagulation function during massive blood transfusion, the ratio between fresh frozen plasma and erythrocyte is recommended to be 2:1 in patients of coagulation dysfunction in order to improve the patient's coagulation function and to reduce the incidence of adverse event, the ratio of fresh frozen plasma to erythrocyte is recommended to be 1:1 in patients with normal coagulation so as to reduce the dilutional coagulopathy and hypervolemia of blood.

  9. THE MERGER-DRIVEN EVOLUTION OF MASSIVE GALAXIES

    SciTech Connect

    Robaina, Aday R.; Van der Wel, Arjen; Skelton, Rosalind E.; Meisenheimer, Klaus; Bell, Eric F.; Somerville, Rachel S.; McIntosh, Daniel H.; Wolf, Christian

    2010-08-10

    We explore the rate and impact of galaxy mergers on the massive galaxy population using the amplitude of the two-point correlation function on small scales for M {sub *} > 5 x 10{sup 10} M {sub sun} galaxies from the COSMOS and COMBO-17 surveys. Using a pair fraction derived from the Sloan Digital Sky Survey as a low-redshift benchmark, the large survey area at intermediate redshifts allows us to determine the evolution of the close-pair fraction with unprecedented accuracy for a mass-selected sample: we find that the fraction of galaxies more massive than 5 x 10{sup 10} M {sub sun} in pairs separated by less than 30 kpc in three-dimensional space evolves as F(z) = (0.0130 {+-} 0.0019) x (1 + z){sup 1.21{+-}0.25} between z = 0 and z = 1.2. Assuming a merger timescale of 0.5 Gyr, the inferred merger rate is such that galaxies with mass in excess of 10{sup 11} M {sub sun} have undergone, on average, 0.5 (0.7) mergers involving progenitor galaxies both more massive than 5 x 10{sup 10} M {sub sun} since z = 0.6 (1.2). We also study the number density evolution of massive red sequence galaxies using published luminosity functions and constraints on the M/L {sub B} evolution from the fundamental plane. Moreover, we demonstrate that the measured merger rate of massive galaxies is sufficient to explain this observed number density evolution in massive red sequence galaxies since z = 1.

  10. Sub-mm free-free emission from the winds of massive stars in the age of ALMA

    NASA Astrophysics Data System (ADS)

    Daley-Yates, S.; Stevens, I. R.; Crossland, T. D.

    2016-09-01

    The thermal radio and sub-mm emission from the winds of massive stars is investigated and the contribution to the emission due to the stellar wind acceleration region and clumping of the wind is quantified. Building upon established theory, a method for calculating the thermal radio and sub-mm emission using results for a line-driven stellar outflow according to Castor, Abbott & Klein (1975) is presented. The results show strong variation of the spectral index for 102 GHz <ν < 104 GHz. This corresponds both to the wind acceleration region and clumping of the wind, leading to a strong dependence on the wind velocity law and clumping parameters. The Atacama Large Millimeter/sub-mm Array (ALMA) is the first observatory to have both the spectral window and sensitivity to observe at the high frequencies required to probe the acceleration regions of massive stars. The deviations in the predicted flux levels as a result of the inclusion of the wind acceleration region and clumping are sufficient to be detected by ALMA, through deviations in the spectral index in different portions of the radio/sub-mm spectra of massive stars, for a range of reasonable mass-loss rates and distances. Consequently both mechanisms need to be included to fully understand the mass-loss rates of massive stars.

  11. A novel effect of Noscapine on patients with massive ischemic stroke: A pseudo-randomized clinical trial

    PubMed Central

    Mahmoudian, Massoud; Rezvani, Mohammad; Rohani, Mohammad; Benaissa, Foozya; Jalili, Mehdi; Ghourchian, Shadi

    2015-01-01

    Background: Massive ischemic stroke causes significant mortality and morbidity in stroke patients. The main treatments for massive ischemic stroke are recombinant tissue plasminogen activator (rtPA), craniotomy, and endovascular interventions. Due to destructive effects of bradykinin on the nervous system in ischemic stroke, it seems reasonable that using Noscapine as a Bradykinin antagonist may improve patients’ outcome after ischemic stroke. The effect of Noscapine on massive ischemic stroke was shown by the previous pilot study by our group. This pseudo-randomized clinical trial study was designed to assess the result of the pilot study. Methods: Patients who had clinical symptoms or computed tomography scan indicative of massive stroke (in full middle cerebral artery territory) were entered to the study. The cases received the drugs according to their turns in emergency ward (pseudo-randomized). The patient group received Noscapine, and the control group received common supportive treatments. The patients and data analyzer were blinded about the data. At the end of the study, to adjust confounding variables we used logistic regression. Results: After 1-month follow-up, 16 patients in the control group and 11 patients in the case group expired (P = 0.193). Analyzing the data extracted from Rankin scale and Barthel index check lists, revealed no significant differences in the two groups. Conclusion: Despite the absence of significant statistical results in our study, the reduction rate of 16% for mortality rate in Noscapine recipients is clinically remarkable and motivates future studies with larger sample sizes. PMID:25874051

  12. Ionizing feedback from massive stars in massive clusters - III. Disruption of partially unbound clouds

    NASA Astrophysics Data System (ADS)

    Dale, J. E.; Ercolano, B.; Bonnell, I. A.

    2013-03-01

    We extend our previous smoothed particle hydrodynamics parameter study of the effects of photoionization from O-stars on star-forming clouds to include initially unbound clouds. We generate a set of model clouds in the mass range 104-106 M⊙ with initial virial ratios Ekin/Epot = 2.3, allow them to form stars and study the impact of the photoionizing radiation produced by the massive stars. We find that, on the 3 Myr time-scale before supernovae are expected to begin detonating, the fraction of mass expelled by ionizing feedback is a very strong function of the cloud escape velocities. High-mass clouds are largely unaffected dynamically, while low-mass clouds have large fractions of their gas reserves expelled on this time-scale. However, the fractions of stellar mass unbound are modest and significant portions of the unbound stars are so only because the clouds themselves are initially partially unbound. We find that ionization is much more able to create well-cleared bubbles in the unbound clouds, owing to their intrinsic expansion, but that the presence of such bubbles does not necessarily indicate that a given cloud has been strongly influenced by feedback. We also find, in common with the bound clouds from our earlier work, that many of the systems simulated here are highly porous to photons and supernova ejecta, and that most of them will likely survive their first supernova explosions.

  13. Massive basketball diagram for a thermal scalar field theory

    SciTech Connect

    Andersen, Jens O.; Braaten, Eric; Strickland, Michael

    2000-08-15

    The ''basketball diagram'' is a three-loop vacuum diagram for a scalar field theory that cannot be expressed in terms of one-loop diagrams. We calculate this diagram for a massive scalar field at nonzero temperature, reducing it to expressions involving three-dimensional integrals that can be easily evaluated numerically. We use this result to calculate the free energy for a massive scalar field with a {phi}{sup 4} interaction to three-loop order. (c) 2000 The American Physical Society.

  14. Electromagnetic field properties in the vicinity of a massive wormhole

    SciTech Connect

    Novikov, I. D.; Shatskiy, A. A.

    2011-12-15

    It is proved that not only massless but also traversable massive wormholes can have electromagnetic 'hair.' An analysis is also presented of the passage from a traversable wormhole to the limit of a Reissner-Nordstroem black hole, with the corresponding disappearance of 'hair.' A general method is developed for solving stationary axisymmetric Maxwell's equations in the field of a massive, spherically symmetric wormhole. As a particular example of application of the method, a solution is found to the axisymmetric magnetostatic problem for a current loop in the field of the Bronnikov-Ellis-Morris-Thorne wormhole.

  15. Formation and Evolution of Massive Stars: Current Surveys

    NASA Astrophysics Data System (ADS)

    de Koter, A.

    2016-10-01

    The advent of multi-object spectrographs on 8-10 m class telescopes has provided the opportunity to perform detailed atmospheric analysis of samples of several hundreds of massive stars, prior studies being limited to several tens of objects at most. These analyses have highlighted some serious problems regarding our understanding of massive-star evolution. A central theme in the findings is the prominent role of multiplicity, with the majority of high-mass stars being in close binary systems of which the components will interact at some point in their lives.

  16. VLT-Flames Tarantula Survey and Multiplicity of Massive Stars

    NASA Astrophysics Data System (ADS)

    Sana, H.

    2013-06-01

    The VLT-Flames Tarantula Survey (VFTS) has obtained optical spectroscopy of over 800 OB and Wolf-Rayet stars in the 30 Doradus region with the aim to investigate a number of questions regarding the formation, evolution and final fate of the most massive stars and the dynamics of the region. In this presentation, I will review some of the most important results obtained by the VFTS so far. The multi-epoch strategy was designed to identify spectroscopic binaries, and I will describe the binary properties in the 30 Dor region in the broader context of our knowledge of the multiplicity of massive stars.

  17. RAMA: A file system for massively parallel computers

    NASA Technical Reports Server (NTRS)

    Miller, Ethan L.; Katz, Randy H.

    1993-01-01

    This paper describes a file system design for massively parallel computers which makes very efficient use of a few disks per processor. This overcomes the traditional I/O bottleneck of massively parallel machines by storing the data on disks within the high-speed interconnection network. In addition, the file system, called RAMA, requires little inter-node synchronization, removing another common bottleneck in parallel processor file systems. Support for a large tertiary storage system can easily be integrated in lo the file system; in fact, RAMA runs most efficiently when tertiary storage is used.

  18. Massive gravity coupled to Galileons is ghost-free.

    PubMed

    Andrews, Melinda; Goon, Garrett; Hinterbichler, Kurt; Stokes, James; Trodden, Mark

    2013-08-01

    It is possible to couple Dirac-Born-Infeld scalars possessing generalized Galilean internal shift symmetries (Galileons) to nonlinear massive gravity in four dimensions, in such a manner that the interactions maintain the Galilean symmetry. Such a construction is of interest, because it is not possible to couple such fields to massless general relativity in the same way. We show that this theory has the primary constraint necessary to eliminate the Boulware-Deser ghost, thus preserving the attractive properties of both the Galileons and ghost-free massive gravity.

  19. Escape of gravitational radiation from the field of massive bodies

    NASA Technical Reports Server (NTRS)

    Price, Richard H.; Pullin, Jorge; Kundu, Prasun K.

    1993-01-01

    We consider a compact source of gravitational waves of frequency omega in or near a massive spherically symmetric distribution of matter or a black hole. Recent calculations have led to apparently contradictory results for the influence of the massive body on the propagation of the waves. We show here that the results are in fact consistent and in agreement with the 'standard' viewpoint in which the high-frequency compact source produces the radiation as if in a flat background, and the background curvature affects the propagation of these waves.

  20. Massive gravity coupled to Galileons is ghost-free.

    PubMed

    Andrews, Melinda; Goon, Garrett; Hinterbichler, Kurt; Stokes, James; Trodden, Mark

    2013-08-01

    It is possible to couple Dirac-Born-Infeld scalars possessing generalized Galilean internal shift symmetries (Galileons) to nonlinear massive gravity in four dimensions, in such a manner that the interactions maintain the Galilean symmetry. Such a construction is of interest, because it is not possible to couple such fields to massless general relativity in the same way. We show that this theory has the primary constraint necessary to eliminate the Boulware-Deser ghost, thus preserving the attractive properties of both the Galileons and ghost-free massive gravity. PMID:23971555