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Sample records for massive haemoptysis due

  1. Massive haemoptysis on veno-arterial extracorporeal membrane oxygenation.

    PubMed

    Harrison, Meredith; Cowan, Scott; Cavarocchi, Nicholas; Hirose, Hitoshi

    2012-09-01

    A 49-year old female presented with severe heart failure with end-organ dysfunction and was placed on veno-arterial extracorporeal membrane oxygenation (ECMO) as a bridge to a decision for end-organ recovery. While on ECMO, the patient developed massive haemoptysis after a Swan-Ganz catheter manipulation. The haemoptysis was not controllable by conventional methods including bronchoscopy with cold saline and epinephrine lavage, bronchial blocker or angiography. The endotracheal tube was clamped to provide tamponade and the patient relied on full ECMO support for 36 h. After the haemoptysis resolved, the endotracheal tube was unclamped. The patient developed adult respiratory distress syndrome and was ventilated using the ARDSnet protocol with continued support from ECMO. On post-ECMO day 20, the patient underwent a successful ECMO wean and a Heart Mate II left ventricular assist device placement.

  2. An unusual and deadly cause for massive haemoptysis

    PubMed Central

    Naha, Kushal; Shetty, Ranjan K; Vivek, G; Magazine, Rahul

    2013-01-01

    We report a 47-year-old man with diabetics presenting with massive haemoptysis. Physical examination showed moderate pallor, but was otherwise normal. Evaluation showed normal bleeding and clotting parameters. Aerobic cultures of sputum samples and acid-fast staining were negative. CT showed fusiform aneurysmal dilation of the descending thoracic aorta compressing the left main bronchus with secondary collapse of the left lower and lingular lobes. Massive haemoptysis was attributed to probable erosion of the aneurysm into the left main bronchus. Retrospective questioning failed to elicit pathognomic symptoms of aortic aneurysm including chest pain. While in the hospital, the patient had another bout of massive haemoptysis, requiring endotracheal intubation for airway protection. Chest x-ray revealed homogeneous opacification of the left hemithorax. The patient was treated with antitussives and blood transfusions and referred to a higher centre for endovascular stent grafting of the aneurysm and simultaneous surgical repair of the left main bronchus. Aortic aneurysm is a rare but deadly cause for haemoptysis, as rapid exsanguination can lead to cardiovascular collapse and death. PMID:23413292

  3. Massive haemoptysis following dabigatran administration in a patient with bronchiectasis.

    PubMed

    Hayama, Manabu; Inoue, Hideki; Wada, Hiromichi; Mio, Tadashi

    2014-02-19

    We report a case of life-threatening haemoptysis after administration of dabigatran in a patient with bronchiectasis. A 72-year-old woman had received dabigatran at a dose of 110 mg twice daily for chronic atrial fibrillation. She was admitted to our hospital for cerebral infarction after a few days of self-interruption of dabigatran. After the diagnosis of cerebral infarction, administration of dabigatran was restarted. Seven days later, she suffered acute-onset massive haemoptysis and required mechanical ventilation. Dabigatran treatment was discontinued, and bronchial artery embolisation (BAE) was performed twice. The bleeding continued for 11 days, but she recovered and was discharged on day 58 after admission.

  4. Massive haemoptysis following dabigatran administration in a patient with bronchiectasis

    PubMed Central

    Hayama, Manabu; Inoue, Hideki; Wada, Hiromichi; Mio, Tadashi

    2014-01-01

    We report a case of life-threatening haemoptysis after administration of dabigatran in a patient with bronchiectasis. A 72-year-old woman had received dabigatran at a dose of 110 mg twice daily for chronic atrial fibrillation. She was admitted to our hospital for cerebral infarction after a few days of self-interruption of dabigatran. After the diagnosis of cerebral infarction, administration of dabigatran was restarted. Seven days later, she suffered acute-onset massive haemoptysis and required mechanical ventilation. Dabigatran treatment was discontinued, and bronchial artery embolisation (BAE) was performed twice. The bleeding continued for 11 days, but she recovered and was discharged on day 58 after admission. PMID:24554673

  5. Management of massive haemoptysis with the rigid bronchoscope and cold saline lavage.

    PubMed Central

    Conlan, A A; Hurwitz, S S

    1980-01-01

    Twelve successive patients with massive haemoptysis were treated by emergency rigid bronchoscopy and lavage of the bleeding lung with cold saline. All patients stopped bleeding during the procedure and all blood and clot was evacuated from the accessible airways. The bleeding source was localised to a lobe in seven cases, and lateralised in the remaining five patients. Five patients had a second haemorrhage during that hospital stay and cold saline lavage again terminated it. Further therapy, either surgical or medical was based on information obtained during the respite from haemorrhage achieved with this technique. There was no hospital mortality in the series. PMID:7268664

  6. Teflon haemoptysis.

    PubMed

    Aboudara, Matthew; Krimsky, William; Harley, Daniel

    2012-03-20

    Teflon-coated pledgeted sutures can be used to reinforce the bronchial anastomosis site following a pulmonary resection in order to prevent bronchopleural fistula formation. The authors describe the case of a 42-year-old woman with recurrent haemoptysis secondary to the erosion of a pledgeted suture through the distal trachea. The pledgeted suture was used to reinforce a defect in the wall of the distal trachea after a right upper lobectomy for stage 2a squamous cell carcinoma. Surgically, a completion pneumonectomy with carinal reconstruction was thought necessary to treat the haemoptysis. Given her age and potential surgical morbidities, the decision was made to perform serial bronchoscopies with careful pruning and eventual removal of the pledget by using the cryoprobe and a flexible scissors. This resulted in the eventual removal of the suture. Follow-up bronchoscopy 4 weeks postremoval demonstrated no residual defect on the airway wall.

  7. Massive ovarian edema, due to adjacent appendicitis.

    PubMed

    Callen, Andrew L; Illangasekare, Tushani; Poder, Liina

    2017-04-01

    Massive ovarian edema is a benign clinical entity, the imaging findings of which can mimic an adnexal mass or ovarian torsion. In the setting of acute abdominal pain, identifying massive ovarian edema is a key in avoiding potential fertility-threatening surgery in young women. In addition, it is important to consider other contributing pathology when ovarian edema is secondary to another process. We present a case of a young woman presenting with subacute abdominal pain, whose initial workup revealed marked enlarged right ovary. Further imaging, diagnostic tests, and eventually diagnostic laparoscopy revealed that the ovarian enlargement was secondary to subacute appendicitis, rather than a primary adnexal process. We review the classic ultrasound and MRI imaging findings and pitfalls that relate to this diagnosis.

  8. 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.

  9. Recurrent massive ascites due to mossy endometriosis.

    PubMed

    Dun, Erica C; Wong, Serena; Lakhi, Nisha A; Nehzat, Ceana H

    2016-11-01

    To report the medical and surgical management of a rare case of recurrent moss-like endometriosis and associated hemorrhagic ascites. Video description of the case, demonstration of the surgical technique, discussion of the histology, and review of endometriosis-associated ascites. Tertiary referral center. A 26-year-old nulliparous woman of Nigerian heritage with recurrent hemorrhagic ascites due to endometriosis. Three years previously she underwent an exploratory laparotomy for similar symptoms, and 7 L of hemorrhagic ascites were evacuated from her abdomen. Friable lesions covering the peritoneum of the uterus, bladder, and pouch of Douglas were biopsied and consistent with endometriosis. After her initial surgery, the patient was hormonally suppressed with goserelin for 3 months and oral medroxyprogesterone for 1 year. She then stopped the medications to attempt pregnancy but was unsuccessful. She used clomiphene for 3 months, and the ascites reaccumulated. The patient was started on depot leuprolide and oral norethindrone, but the ascites persisted. The patient underwent small-diameter laparoscopy using a multipuncture technique, evacuation of 7.8 L of hemorrhagic ascites, enterolysis, appendectomy, chromopertubation, and treatment of the endometriosis. Diffuse olive-green "mossy" endometriosis lesions blanketed the pelvic and abdominal peritoneum. The endometriosis was surgically resected with a combination of peritoneal stripping, excision with carbon dioxide laser, and ablation with neutral argon plasma. Examination of the ascites showed scattered hemosiderin-laden macrophages in a background of red blood cells. Histology of the olive-green mossy lesions revealed dense sheets of hemosiderin-laden macrophages and rare foci of endometriosis. Surgical reports in deidentified patients are exempted from Institutional Review Board approval. The patient gave consent to use photography and images for the video article. No postoperative hormone suppression was

  10. Respiratory failure due to a massive rheumatoid pleural effusion.

    PubMed

    Pritikin, J D; Jensen, W A; Yenokida, G G; Kirsch, C M; Fainstat, M

    1990-05-01

    A patient with rheumatoid arthritis (RA) and chronic obstructive lung disease was admitted with respiratory failure due to a massive pleural effusion. An extensive evaluation proved the effusion to be of rheumatoid origin. The effusion resolved with prednisone and penicillamine therapy. Although pleural effusions associated with RA are common, massive effusions are rare and respiratory failure from a rheumatoid pleural effusion has not been reported.

  11. Thoracic surgery for haemoptysis in the context of tuberculosis: what is the best management approach?

    PubMed

    Halezeroğlu, Semih; Okur, Erdal

    2014-03-01

    Haemoptysis is not an unusual finding in patients with old or active pulmonary tuberculosis. Because of bronchial artery or a branch of pulmonary artery erosion due to cavitary infiltration, bronchiectasis, fungus ball, broncholithiasis or destroyed lung, the bleeding can sometimes be a life-threatening situation. Assessment of the patient and finding the exact site of bleeding can be difficult especially in a patient with disseminated lung disease. Chest computerized tomography and bronchoscopy remain the methods of choice for lateralization of the disease. Some patients can be treated successfully with endobronchial interventions. Bronchial artery embolization can be rewarding in some patients but the recurrence rate is higher in tuberculosis than other etiologies of haemoptysis. Surgical resection of the lung, mainly lobectomy, remains a life-saving procedure but it should be performed very selectively to avoid higher postoperative morbidity and mortality. Different management options of haemoptysis in patients with pulmonary tuberculosis are discussed in this manuscript.

  12. Gastric Necrosis due to Acute Massive Gastric Dilatation

    PubMed Central

    Pergel, Ahmet; Yucel, Ahmet Fikret; Sahin, Dursun Ali; Ozer, Ender

    2013-01-01

    Gastric necrosis due to acute massive gastric dilatation is relatively rare. Vascular reasons, herniation, volvulus, acute gastric dilatation, anorexia, and bulimia nervosa play a role in the etiology of the disease. Early diagnosis and treatment are highly important as the associated morbidity and mortality rates are high. In this case report, we present a case of gastric necrosis due to acute gastric dilatation accompanied with the relevant literature. PMID:23983714

  13. Efficacy and safety of super selective bronchial artery coil embolisation for haemoptysis: a single-centre retrospective observational study

    PubMed Central

    Ishikawa, Hideo; Hara, Masahiko; Ryuge, Misaki; Takafuji, Jun; Youmoto, Mihoko; Akira, Masanori; Nagasaka, Yukio; Kabata, Daijiro; Yamamoto, Kouji; Shintani, Ayumi

    2017-01-01

    Objectives Evidence on the safety and long-term efficacy of super selective bronchial artery embolisation (ssBAE) using platinum coils in patients with haemoptysis is insufficient. The objective of the present study was to evaluate the safety and the 3-year postprocedure haemoptysis-free survival rate of de novo elective ssBAE using platinum coils rather than particles for the treatment of haemoptysis. Design A single-centre retrospective observational study. Setting Hemoptysis and Pulmonary Circulation Center in Japan. Participants A total of 489 consecutive patients with massive and non-massive haemoptysis who underwent de novo elective ssBAE without malignancy or haemodialysis. Interventions ssBAE using platinum coils. All patients underwent CT angiography before the procedure for identifying haemoptysis-related arteries (HRAs) and for procedural planning. Primary and secondary outcome measures The composite of the 3-year recurrence of haemoptysis and mortality from the day of the last ssBAE session. Each component of the primary end point and procedural success defined as successful embolisation of all target HRAs were also evaluated. Results The median patient age was 69 years, and 46.4% were men. The total number of target vessels was 4 (quartile 2–7), and the procedural success rate was 93.4%. There were 8 (1.6%) major complications: 1 aortic dissection, 2 symptomatic cerebellar infarctions and 5 mediastinal haematoma cases. The haemoptysis-free survival rates were estimated by the Kaplan-Meier analysis at 86.9% (95% CI 83.7% to 90.2%) at 1 year, 79.4% (74.8% to 84.3%) at 2 years and 57.6% (45.1% to 73.4%) at 3 years. Although not statistically significant by the adjusted analysis of variance with multiple imputation of missing variables, cryptogenic haemoptysis tended to show the most favourable outcome and non-tuberculous mycobacterium showed the worst outcome (adjusted p=0.250). Conclusions We demonstrated the safety and long-term efficacy of

  14. [Massive traumatic hemoptysis].

    PubMed

    Bourdereau, J M; Mathé, D; Voultoury, J C

    1985-01-01

    A case is reported of a patient who suffered a rupture of one lung as result of thoracic trauma. This gave rise to respiratory distress with massive haemoptysis which was initially treated with a double-lumen endotracheal tube, with separate lung ventilation, a chest drain and massive transfusion. A haemostatic pneumonectomy had to be performed because of the persisting and profuse bleeding.

  15. 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.

  16. 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

  17. Endobronchial valves in the management of recurrent haemoptysis.

    PubMed

    Koegelenberg, Coenraad F N; Bruwer, Johannes W; Bolliger, Chris T

    2014-01-01

    Minimally invasive treatment modalities for life-threatening haemoptysis in patients unresponsive to medical interventions and/or in patients deemed functionally inoperable are limited. We describe the implantation of endobronchial valves in a patient with recurrent haemoptysis, which presents both a novel indication for the use of these devices and a novel intervention for haemoptysis. Our patient is a 30-year-old male who developed bilateral upper lobe aspergillomata following previous pulmonary tuberculosis. The patient had a history of multiple hospitalisations for life-threating haemoptysis despite repeated bronchial artery embolisations. He was deemed to be inoperable given the bilateral nature of his disease and very poor pulmonary reserves. We proceeded to identify the segments involved with the aid of computed tomography reconstruction and implanted 3 endobronchial valves. Our patient remained haemoptysis free for 6 months and experienced no stent-related complications. Moreover, he was subsequently employed as a manual labourer and showed significant improvements in his functional capacity. Endobronchial valves may therefore represent a viable medium-term treatment option as a blockade device in patients unresponsive to medical interventions and/or in patients deemed functionally inoperable. Prospective studies are indicated to better delineate the role of endobronchial valves in this setting. © 2013 S. Karger AG, Basel.

  18. [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. Copyright © 2009 Elsevier España, S.L. y SEMICYUC. All rights reserved.

  19. Survival of acute hypernatremia due to massive soy sauce ingestion.

    PubMed

    Carlberg, David J; Borek, Heather A; Syverud, Scott A; Holstege, Christopher P

    2013-08-01

    Intentional massive sodium chloride ingestions are rare occurrences and are often fatal. There are a variety of treatment recommendations for hypernatremia, ranging from dialysis to varying rates of correction. We report a case of acute severe hypernatremia corrected with rapid free-water infusions that, to our knowledge, has not been previously reported. A 19-year-old man presented to the Emergency Department in a comatose state with seizure-like activity 2 hours after ingesting a quart of soy sauce. He was administered 6 L of free water over 30 min and survived neurologically intact without clinical sequelae. Corrected for hyperglycemia, the patient's peak serum sodium was 196 mmol/L, which, to our knowledge, is the highest documented level in an adult patient to survive an acute sodium ingestion without neurologic deficits. Emergency physicians should consider rapidly lowering serum sodium with hypotonic intravenous fluids as a potential management strategy for acute severe hypernatremia secondary to massive salt ingestion. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. [Tracheobronchopathia osteochondrodysplasias. About one case revealed by haemoptysis].

    PubMed

    Abid, Leïla; Ayadi-Kaddour, Aïda; Braham, Emna; Ismail, Olfa; Tritar, Fatma; Meraï, Samira; El Mezni, Faouzi

    2006-11-01

    Tracheobronchopathia osteochondrodysplasias is a benign and rare chronic disease, whose etiology remains obscure. It is characterized by the presence of subepithelial osteocartilaginous focal lesions without any relation to tracheal rings, essentially localized in the lower two thirds of the trachea and the major bronchi. We report a new case of tracheobronchopathia osteochondrodysplasias in a 47-year-old man, localized at the lower half of the trachea, revealed by haemoptysis. The lesion was suspected by bronchoscopy and the diagnosis was made histologically, showing heterotopic bone formation. The evolution of this affection was marked by a good clinical tolerance with only a symptomatic treatment.

  1. 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. Copyright ©ERS 2015.

  2. Hyperparathyroid crisis due to asymmetric parathyroid hyperplasia with a massive ectopic parathyroid gland.

    PubMed

    Gratian, Lauren F; Hyland, Kristen A; Scheri, Randall P

    2014-10-01

    To report a rare case of primary hyperparathyroidism presenting with hyperparathyroid crisis due to parathyroid hyperplasia with ectopic glands. We present the initial clinical manifestations, laboratory results, radiologic and surgical findings, and management in a patient who had hyperparathyroid crisis. The pertinent literature and management options are also reviewed. A 60-year-old female presented with hyperparathyroid crisis requiring preoperative stabilization with rehydration, diuresis, bisphosphonate therapy, and ultimately hemodialysis. Parathyroidectomy revealed asymmetric 4-gland hyperplasia, with a massive ectopic parathyroid gland in the tracheoesophageal groove extending into the mediastinum. Her postoperative course was complicated by hungry bone syndrome and hypocalcemia. This case illustrates the rare occurrence of hyperparathyroid crises due to asymmetric parathyroid hyperplasia with a massive ectopic parathyroid gland.

  3. 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.

  4. Massive lower gastrointestinal bleeding due to 'Dieulafoy's vascular malformation' of the jejunum: case report.

    PubMed Central

    Goins, W. A.; Chatman, D. M.; Kaviani, M. J.

    1995-01-01

    Dieulafoy reported three cases of massive gastric hemorrhage due to a dilated submucosal artery in 1898, and since then, more than 100 cases of this gastric vascular malformation have been reported in the literature. These same pathologic lesions are even a rarer occurrence in the small bowel. This article reports a 38-year-old hypotensive male who presented to the hospital after an acute onset of massive lower gastrointestinal hemorrhage; superior mesenteric angiography demonstrated an actively bleeding lesion in a proximal jejunal branch. Intraoperative small bowel endoscopy via an enterotomy demonstrated a 4 mm bleeding submucosal lesion 30 cm distal to the ligament of Treitz. A literature review revealed six other cases of Dieulafoy's vascular malformation that occurred in the small bowel, with the lesions located in the proximal jejunum between 15 cm and 45 cm distal to the ligament of Treitz. The cause of these lesions is unknown. This case demonstrates the importance of preoperative angiography and intraoperative endoscopy when massive lower gastrointestinal hemorrhage is suspected to be from a small bowel source. Images Figure 1 Figure 2 Figure 3 PMID:7473854

  5. Effectiveness of milrinone for cardiogenic shock due to massive pulmonary aspiration: a case report

    PubMed Central

    Park, Jeong Heon; Kim, Dong Hee; Kim, Seok-Kon; Jeon, Dae Geun; Song, Jaegyok; Ji, Seung Heon; Lee, Gwan Woo; Kang, Bong Jin

    2014-01-01

    Pulmonary aspiration of gastric contents is one of the most frightening complications during anesthesia. Although pulmonary aspiration of gastric contents in general surgical patients is not common and resulting long-term morbidity and mortality are rare, severe hypoxemia and other sequelae of pulmonary aspiration continue to be reported. We report a case of massive aspiration of gastric contents during induction of general anesthesia, resulting in cardiac arrest due to severe pulmonary hypertension and myocardial infarction. Sustained cardiac arrest and shock that did not respond the conventional resuscitation was successfully treated using milrinone. The patient was discharged without complications in 20 days. PMID:25006374

  6. Recurrent massive hemoperitoneum due to ovulation as a clinical sign in congenital afibrinogenemia.

    PubMed

    Cetinkaya, Serife Esra; Pabuccu, Emre Goksan; Ozmen, Batuhan; Dokmeci, Fulya

    2011-02-01

    Massive hemoperitoneum due to ovulation is a rare but serious and life-threatening complication for women with coagulation disorders, and may lead to surgical interventions and even oophorectomy. Congenital afibrinogenemia is an uncommon coagulation disorder usually discovered during childhood. Intraabdominal bleeding due to ovulation is very rare in these patients and only a few cases of corpus luteum rupture and hemoperitoneum in afibrinogenemic patients have been described. In all women, the diagnosis was known since childhood. We report on a 24-year-old woman with congenital afibrinogenemia with recurrent massive intraabdominal bleeding due to ovulation as the presenting clinical sign. Exploratory laparotomy and excision of the ruptured follicle was performed at the first bleeding episode; the second episode was managed with fresh frozen plasma and blood transfusions. Conservative management is crucial for these patients. If surgery cannot be avoided, a conservative surgical approach should be chosen to preserve ovarian function. © 2010 The Authors Acta Obstetricia et Gynecologica Scandinavica© 2010 Nordic Federation of Societies of Obstetrics and Gynecology.

  7. Triaxial system in bronchial arterial embolization for haemoptysis using N-butyl-2-cyanoacrylate

    PubMed Central

    Hashimoto, Takeshi; Abematsu, Saori; Hashizume, Takuya; Nakagawa, Motoo; Ozawa, Yoshiyuki; Sakurai, Keita; Shibamoto, Yuta

    2015-01-01

    Objective: The application of bronchial artery embolization (BAE) using N-butyl-2-cyanoacrylate (NBCA) for haemoptysis was recently reported to be useful. A triple co-axial (triaxial) system consisting of a 4-Fr catheter, 2.7-Fr microcatheter and 1.9-Fr no-taper microcatheter has been developed. The aim of the present study was to evaluate the usefulness of the triaxial system in BAE using NBCA. Methods: 12 patients with haemoptysis, 8 males and 4 females with a median age of 64 years (range, 49–88 years), underwent BAE between August 2012 and October 2014. Medical records and images were reviewed, and the technical success rate, clinical success rate, haemoptysis-free rate and complications were evaluated. Technical success was defined as the complete cessation of the target artery as confirmed by digital subtraction angiography, whereas clinical success was defined as the cessation of haemoptysis within 24 h of BAE. Recurrent haemoptysis was defined as a total of >30 ml of bleeding per day. Results: The target artery was embolized successfully in all patients, and the technical success rate was 100% (12/12). The cessation of haemoptysis was achieved in 11 out of 12 patients within 24 h, and thus, the clinical success rate was 92% (11/12). The 6-, 12- and 24-month haemoptysis-free rates were 89%, 89% and 76%, respectively. No patients exhibited any signs of complications such as spinal ischaemia. Conclusion: BAE using the triaxial system and NBCA appears to be a useful and safe procedure for haemoptysis. Advances in knowledge: The triaxial system contributes to safe and effective BAE using NBCA. PMID:26423598

  8. 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

  9. Outcomes of partial splenic embolization in patients with massive splenomegaly due to idiopathic portal hypertension

    PubMed Central

    Ozturk, Omer; Eldem, Gonca; Peynircioglu, Bora; Kav, Taylan; Görmez, Aysegul; Cil, Barbaros Erhan; Balkancı, Ferhun; Sokmensuer, Cenk; Bayraktar, Yusuf

    2016-01-01

    AIM To determine the outcomes of partial splenic embolization (PSE) for massive splenomegaly due to idiopathic portal hypertension (IPH). METHODS In this prospective study, we evaluated the characteristics and prognosis of consecutive patients with IPH who underwent PSE for all indications at a single medical center between June 2009 and January 2015. The inclusion criteria were: presence of hypersplenism, massive splenomegaly, and resultant pancytopenia. The exclusion criteria were: presence of other diseases causing portal hypertension. During the post-PSE period, the patients were hospitalized. All patients underwent abdominal computed tomography imaging 4 wk post-PSE to determine total splenic and non-infarcted splenic volumes. RESULTS A total of 11 patients, with median age of 33.27 ± 4.8 years, were included in the study. Mean spleen size was 22.9 cm (21-28 cm), and severe hypersplenism was diagnosed in all patients before PSE. Post-PSE, leukocyte and platelet counts increased significantly, reaching peak levels in the second week with gradual decreases thereafter. Liver function tests did not exhibit significant changes during post-intervention follow-up. All patients developed post-embolization syndrome, and one patient experienced serious complications; all complications were successfully treated with conservative therapy and no death occurred. CONCLUSION Our findings showed that PSE has a lower complication rate than previously-reported surgical complication rates, which supports this intervention as a viable alternative for high-risk operable patients with severe hypersplenism. PMID:27920483

  10. 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

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

    PubMed Central

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

    2015-01-01

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

  12. Ileocecal resection for massive rectal bleeding due to Yersinia enterocolitica: a case report and review of the literature.

    PubMed

    Azghari, Ilham; Bargach, Aicha; Billah, Nabil Moatassim; Essaoudi, Mohamed Amine; Jahid, Ahmed; Kabbaj, Nawal

    2016-01-19

    Massive gastrointestinal bleeding is an emergency that can sometimes require immediate surgery. We report the first case, to the best of our knowledge, of massive rectal bleeding due to Yersinia enterocolitica, requiring ileocecal resection. A 41-year-old North African woman was admitted to our emergency department for massive rectal bleeding. She had a history of an iron deficiency anemia of unknown cause, and diarrhea 2 months before the admission. On admission to our emergency unit, she was in a state of hemodynamic collapse. An examination showed discolored conjunctivas, massive rectal bleeding with clots and no abdominal pain. The first medical treatment included the use of noradrenaline. An upper gastrointestinal endoscopy was performed and did not show any lesions. Computed tomography of her abdomen showed significant and hypervascular wall thickening of her terminal ileum suggestive of a tumor. Because her massive rectal bleeding worsened and her collapse persisted, an exploratory laparotomy and ileocecal resection were immediately performed on the patient. Histopathological analysis showed enteritis caused by Yersinia enterocolitica. Her outcome was favorable. Enteritis due to Yersinia enterocolitica can take a pseudotumoral form and mislead the diagnosis of gastrointestinal bleeding.

  13. [Bleeding during central venous catheterization : Cannot intubate, cannot ventilate due to massive cervical hematoma].

    PubMed

    Engelen, C; Trebes, C; Czarnecki, S; Junger, A

    2016-03-01

    Central venous catheterization is an invasive procedure which can be associated with severe complications. These include in particular unsuccessful arterial puncture and vascular injuries, which in addition to loss of blood can lead to massive soft tissue swelling. A 63-year-old female patient developed massive cervical bleeding during ultrasound-guided internal jugular vein puncture and the rapidly enlarging hematoma led to compromisation of the airway. A cannot intubate, cannot ventilate situation developed and the subsequent hypoxia led to cardiac arrest that was only resolved after emergency surgical tracheotomy during cardiopulmonary resuscitation.

  14. 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

  15. Successful treatment of massive ascites due to lupus peritonitis with hydroxychloroquine in old- onset lupus erythematosus.

    PubMed

    Hammami, Sonia; Bdioui, Fethia; Ouaz, Afef; Loghmari, Hichem; Mahjoub, Sylvia; Saffar, Hamouda

    2014-01-01

    Systemic lupus erythematous (SLE) is an auto-immune disease with multiple organ involvements that occurs mainly in young women. Literature data suggest that serositis is more frequent in late-onset SLE. However, peritoneal serositis with massive ascites is an extremely rare manifestation. We report a case of old-onset lupus peritonitis treated successfully by Hydroxychloroquine. A 77-year-old Tunisian woman was hospitalized because of massive painful ascites. Her family history did not include any autoimmune disease. She was explored 4 years prior to admission for exudative pleuritis of the right lung without any established diagnosis. Physical examination showed only massive ascites. Laboratory investigations showed leucopenia: 3100/mm3, lymphopenia: 840/mm3 and trace protein (0.03 g/24 h). Ascitic fluid contained 170 cells mm(3) (67% lymphocytes), 46 g/L protein, but no malignant cells. The main etiologies of exudative ascites were excluded. She had markedly elevated anti-nuclear antibody (ANA) titer of 1/1600 and a significantly elevated titer of antibody to double-stranded DNA (83 IU/mL) with hypo-complementemia (C3 levl was at 67 mg/dL). Antibody against the Smith antigen was also positive. Relying on these findings, the patient was diagnosed with SLE and treated with Hydroxychloroquine 200 mg daily in combination with diuretics. One month later, there was no detectable ascitic fluid and no pleural effusions. Five months later she remained free from symptoms while continuing to take chloroquine. This case was characterized by old age of onset of SLE, the extremely rare initial presentation with lupus peritonitis and massive painful ascites with dramatic response to only hydroxychloroquine treatment.

  16. 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.

  17. 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

  18. [The Seebauer classification for the staging of arthropathy due to rotator cuff massive tear: intra- and interobserver concordance analysis].

    PubMed

    Guerra-Soriano, F; Ruiz-Suárez, M; Encalada-Díaz, M I; Pérez-Domenech, J; Moscona-Mishy, L; Valero-González, F S

    2010-01-01

    L. Seebauer developed a radiologic classification of arthropathy due to massive rotator cuff tear, based on the medial and/or proximal displacement of the humeral head as a result of disease progression. The purpose of this paper is to conduct an evaluation of the concordance of such classification. A group of 34 patients with massive rotator cuff lesion was created. Their X-rays were reviewed and classified by 5 independent observers. An inter- and intraobserver concordance analysis was carried out using the Kappa index, and the results were interpreted according to the Landis and Kock criteria. The intraobserver concordance determined for the 5 observers showed that the one with the greatest experience had an agreement close to 100%; the interobserver concordance found that only 2 of the 5 observers had moderate agreement and, finally, the interobserver concordance of the stages of classification 2A showed a substantial agreement, while a moderate agreement was found for IA and IB. An important variability was found in the intraobserver concordance, where the capacity to reproduce the same results depends on the observer's experience. The results of the interobserver concordance show that the criteria established by Seebauer are insufficient to be reproduced. Finally, in the concordance among the stages a moderate agreement was found in each of the stages. The results of this paper show that the Seebauer classification is experience-dependent, which hinders its routine use by orthopedists not sufficiently trained on shoulder surgery or by residents in training.

  19. Haemosuccus pancreaticus due to true splenic artery aneurysm: a rare cause of massive upper gastrointestinal bleeding.

    PubMed

    Sadhu, S; Sarkar, S; Verma, R; Dubey, Sk; Roy, Mk

    2010-07-01

    "Haemosuccus pancreaticus" is an unusual cause of severe upper gastrointestinal bleeding and results from rupture of splenic artery aneurysm into the pancreatic duct. More commonly, it is a pseudoaneurysm of the splenic artery which develops as sequelae of pancreatitis. However, true aneurysm of the splenic artery without pancreatitis has rarely been incriminated as the etiologic factor of this condition. Owing to the paucity of cases and limited knowledge about the disease, diagnosis as well as treatment become challenging. Here we describe a 60-year-old male presenting with severe recurrent upper gastrointestinal bleeding and abdominal pain, which, after considerable delay, was diagnosed to be due to splenic artery aneurysm. Following an unsuccessful endovascular embolisation, the patient was cured by distal pancreatectomy and ligation of aneurysm.

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

    PubMed

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

    2016-09-01

    Amyloid primarily affecting the lungs is a seldom seen clinical entity. This case discusses the work-up of a patient presenting with exercise-induced haemoptysis and diffuse cystic lung disease on radiographic imaging. The common clinical and radiographic findings of diffuse cystic lung diseases as well as a brief overview of pulmonary amyloid are presented. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  1. 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.

    2016-01-01

    Global temperature rise and extremes accompanying drought threaten forests1, 2and their associated climatic feedbacks3, 4. Our ability to accurately simulate drought-induced forest impacts remains highly uncertain5, 6 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.

  2. 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.

  3. [Pulmonary mucormycosis in a patient with kidney transplant and uncontrolled haemoptysis].

    PubMed

    Navarro Vergara, Dulce Iliana; Barragán Pola, Gloria; Bonifaz, Alexandro; Núñez Pérez-Redondo, Carlos; Choreño García, Omar; Cicero Sabido, Raúl

    2017-07-27

    Pulmonary mucormycosis is a rare opportunistic infection with high mortality that is caused by species of Mucorales. The most common species involved are Rhizopus, Mucor, Lichtheimia, and Rhizomucor. A 56 year-old woman presented with a clinical history of diabetes mellitus type 2 and chronic renal disease. She underwent a cadaveric kidney transplantation two years before her admission, for which immunomodulating therapy with thymoglobulin, tacrolimus, mofetil-microphenolate and prednisone was established. The patient suffered a pneumonic process with cough, expectoration, and dyspnoea. The computed tomography scan showed a cavitation in the right upper lobe. With all these findings an invasive broncopulmonary aspergillosis was suspected and the patient began an antifungal treatment with voriconazole without improvement. Rhizomucor pusillus was isolated from a clinical specimen obtained by fine needle aspiration, and its identification was confirmed by PCR. After this finding amphotericin B was administered, but the patient had an uncontrolled haemoptysis and died. Pulmonary mucormycosis is a rare infection, usually fatal in kidney transplant recipients with anti-rejection therapy. Mucorales species usually produce thrombotic phenomena, associated with necrosis and parenchymal destruction that caused a fatal uncontrolled haemoptysis in our patient. Early diagnosis is important in order to perform any surgical treatment and to administer amphotericin B. Copyright © 2017 Asociación Española de Micología. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. 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

  5. Haemoptysis in a teenager: late diagnosis of unnoticed foreign body aspiration.

    PubMed

    Kargl, Simon; Frechinger, Bettina; Pumberger, Wolfgang

    2014-12-22

    Chest X-ray in a 17-year-old boy, presenting with haemoptysis, revealed a radiopaque foreign body (FB) in the right lower lobe. There was no history of aspiration. CT located the needle-shaped FB in the right posterobasal lower lobe segment bronchus. In bronchoscopy, the FB turned out to be a pin, of which the radiolucent plastic head was embedded in the peribronchial tissue. Extraction by flexible and rigid bronchoscopy failed; finally, thoracotomy and bronchotomy had to be performed to remove the pin. In delayed diagnosis of a tracheobronchial FB, CT scan is not only necessary to localise the FB but also to depict or rule out secondary pulmonary changes. Nevertheless, radiolucent components of a metallic FB might be invisible even in CT, leading to underestimation of its size and extension. Late diagnosis complicates removal of tracheobronchial foreign bodies and may even necessitate open surgery, including pulmonary resections.

  6. Haemoptysis in an intravenous drug user: injection needle impacted in the left main bronchus.

    PubMed

    Shah, Asif R; Smyth, Louise; Tolan, Michael; Bartosik, Waldemar

    2014-04-16

    We report a case of a 35-year-old man who presented with 4-week history of haemoptysis, with a history of intravenous drug use. There was no other significant medical or surgical history and no recollection of any foreign body aspiration. Chest X-ray and CT scan showed 40 mm long needle in left main bronchus, partly lying outside the bronchus into the mediastinum. Flexible and rigid bronchoscopes proved to be unsuccessful in retrieving the needle. We proceeded with left posterolateral thoracotomy and the left main bronchus was explored to take out this 21-gauge (green) injection needle. The distal half of the needle with the sharp end was lying in the mediastinum piercing through the bronchial wall. Surgery was uneventful with good postoperative recovery and the patient was discharged 4 days later.

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

    PubMed

    Kono, Yasuo; Sawada, Maiko; Kano, Tatsuhiko

    2007-12-01

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

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

    PubMed

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

    2014-11-14

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

    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.

  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. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  11. A 50-year-old woman with haemoptysis, cough and tachypnea: cholesterol pneumonia accompanying with pulmonary artery hypertension.

    PubMed

    Li, Mengxi; Zhang, Nuofu; Zhou, Ying; Li, Jinhui; Gu, Yingying; Wang, Jian; Liu, Chunli

    2017-03-01

    Lipoid pneumonia is an uncommon disease caused by the presence of lipid in the alveoli. Here we described a case of a 50-year-old woman with haemoptysis, cough and tachypnea, who was diagnosed with cholesterol pneumonia accompanying with pulmonary artery hypertension. The extremely high pulmonary artery pressure achieved, in this case, is alarming and should alert the physicians that the cholesterol pneumonia may be one of the underlying causes of pulmonary artery hypertension. After a treatment of methylprednisolone, her clinical symptoms were significantly improved, which suggested that steroid might be a promising therapeutic for patients with cholesterol pneumonia.

  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. Massive hemoptysis and complete unilateral lung collapse in pregnancy due to pulmonary tuberculosis with good maternal and fetal outcome: a case report.

    PubMed

    Masukume, Gwinyai; Sengurayi, Elton; Moyo, Phinot; Feliu, Julio; Gandanhamo, Danboy; Ndebele, Wedu; Ngwenya, Solwayo; Gwini, Rudo

    2013-08-22

    We report an extremely rare case of massive hemoptysis and complete left-sided lung collapse in pregnancy due to pulmonary tuberculosis in a health care worker with good maternal and fetal outcome. A 33-year-old human immuno deficiency virus seronegative African health care worker in her fourth pregnancy with two previous second trimester miscarriages and an apparently healthy daughter from her third pregnancy presented coughing up copious amounts of blood at 18 weeks and two days of gestation. She had a cervical suture in situ for presumed cervical weakness. Computed tomography of her chest showed complete collapse of the left lung; subsequent bronchoscopy was apparently normal. Her serum β-human chorionic gonadotropin, tests for autoimmune disease and echocardiography were all normal. Her lung re-inflated spontaneously. Sputum for acid alcohol fast bacilli was positive; our patient was commenced on anti-tuberculosis medication and pyridoxine. At 41 weeks and three days of pregnancy our patient went into spontaneous labor and delivered a live born female baby weighing 2.6 kg with APGAR scores of nine and 10 at one and five minutes respectively. She and her baby are apparently doing well about 10 months after delivery. It is possible to have massive hemoptysis and complete unilateral lung collapse with spontaneous resolution in pregnancy due to pulmonary tuberculosis with good maternal and fetal outcome.

  14. Massive neonatal adrenal enlargement due to cytomegaly, persistence of the transient cortex, and hyperplasia of the permanent cortex: findings in Cushing syndrome associated with hemihypertrophy.

    PubMed

    Carney, J Aidan; Ho, Josephine; Kitsuda, Kazuteru; Young, William F; Stratakis, Constantine A

    2012-10-01

    Described in this article is the massive enlargement of both adrenal glands in 3 newborns-2 girls and 1 boy. Two had hemihypertrophy and other congenital abnormalities but no identified genetic mutation; the third had genetically proven Beckwith-Wiedemann syndrome. Two had severe Cushing syndrome, the third had hypercortisolemia but no clinical Cushing syndrome. Bilateral adrenalectomy cured Cushing syndrome in the 2 with severe symptoms; total adrenal weight in these patients was 44 and 53 g, respectively. Unilateral adrenalectomy was performed in the third patient: the gland weighed 52 g; postoperatively, the patient's hypercortisolemia normalized, and, concomitantly, the enlarged contralateral adrenal gland had a 5-fold decrease in size with slight enlargement 6 years postoperatively. Microscopically, the 3 patients had similar pathology: massive adrenal enlargement due to a combination of cytomegaly, persistence of the transient cortex, and hyperplasia of the permanent cortex. The pathologic findings were most likely the result of the genetic mutation identified in 1 patient and of an unknown mutation in the remaining 2 patients.

  15. Thoracic endometriosis with catamenial haemoptysis and pneumothorax: computed tomography findings and long-term follow-up after danazol treatment

    PubMed Central

    Suwatanapongched, Thitiporn; Boonsarngsuk, Viboon; Amornputtisathaporn, Naparat; Leelachaikul, Paisan

    2015-01-01

    Thoracic endometriosis (TE) is an uncommon disorder affecting women of childbearing age. We herein report clinical and thin-section computed tomography (CT) findings of two cases, in which one woman presented with catamenial haemoptysis (CH) alone and another woman presented with bilateral catamenial pneumothoraces (CP) coinciding with CH, a rare manifestation of TE. The dynamic changes demonstrated on thin-section chest CT performed during and after menses led to accurate localisation and presumptive diagnosis of TE in both patients. Following danazol treatment, the patient with CH alone had a complete cure, while the patient with CP and CH had an incomplete cure and required long-term danazol treatment. We discuss the role of imaging studies in TE, with an emphasis on the appropriate timing and scanning technique of chest CT in women presenting with CH, potential mechanisms, treatment and patient outcomes. PMID:26243981

  16. Massive Gravity.

    PubMed

    de Rham, Claudia

    2014-01-01

    We review recent progress in massive gravity. We start by showing how different theories of massive gravity emerge from a higher-dimensional theory of general relativity, leading to the Dvali-Gabadadze-Porrati model (DGP), cascading gravity, and ghost-free massive gravity. We then explore their theoretical and phenomenological consistency, proving the absence of Boulware-Deser ghosts and reviewing the Vainshtein mechanism and the cosmological solutions in these models. Finally, we present alternative and related models of massive gravity such as new massive gravity, Lorentz-violating massive gravity and non-local massive gravity.

  17. “REBOA” – Is it Really Safe? A Case with Massive Intracranial Hemorrhage Possibly due to Endovascular Balloon Occlusion of the Aorta (REBOA)

    PubMed Central

    Uchino, Hayaki; Tamura, Nobuichiro; Echigoya, Ryosuke; Ikegami, Tetsunori; Fukuoka, Toshio

    2016-01-01

    Patient: Female, 86 Final Diagnosis: Polytrauma Symptoms: Shock Medication: — Clinical Procedure: Resuscitative endovascular balloon occlusion of the aorta Specialty: Orthopedics and Traumatology Objective: Unusual or unexpected effect of treatment Background: Non-compressible torso hemorrhage continues to be the leading cause of preventable death in trauma patients. Recent case series report that resuscitative endovascular balloon occlusion of the aorta (REBOA) in the trauma population is a technically feasible method to manage the patients with exsanguinating hemorrhage. On the other hand, it seems that REBOA is being widely promoted prematurely. Complications due to REBOA haven’t been reported much in the literature, and they could have been underestimated. Case Report: An 86-year-old female presented to our emergency department following a pedestrian-vehicle accident. On admission, she was hemodynamically unstable with systolic blood pressure (SBP) of 78 mm Hg. She responded to fluid administration, and computed tomography (CT) scan showed cerebral contusion, subarachnoid hemorrhage, pelvic fracture with contrast extravasation, and thoracic spine fracture. Her condition deteriorated after the CT scan, and she became hemodynamically unstable. REBOA was inserted and inflated. Her blood pressure recovered and even became as high as SBP of 180 mm Hg. Transarterial embolization for pelvic fracture was successfully performed. A subsequent head CT scan showed massive intracranial hemorrhage with penetration to the ventricle, which was fatal. She died on the same day due to cerebral herniation. Conclusions: REBOA is now considered as an alternative to resuscitative thoracotomy or even widely indicated to control hemorrhage. We should be more cautious about using REBOA for polytrauma patients since it could make hemorrhage worse. Further research, assessing its potential complications and safety, will be required to elucidate clear indications for REBOA in trauma

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

    PubMed Central

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

    2015-01-01

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

  19. [Massive Upper Airway Bleeding: A Rare Case of Aortobronchial Fistula].

    PubMed

    Gudiel Arriaza, Paola; Sánchez Serrano, Amparo; Marques do Vale, Jorge; Gil Pereira, Isabel; Simões Torres, António; Martín Sánchez, Maria José

    2016-06-01

    Clinical presentation of haemoptysis and haematemesis often generates confusion, becoming a difficult task to determine the source of upper airway bleeding. Aortobronchial fistula is a rare entity, but has been a reported complication in patients that have undergone aortic vascular surgery. A high clinical suspicion is fundamental to making this diagnosis. A 69 year old male, with a previous diagnosis of chronic gastritis, is admitted to the emergency room for vomiting blood. In the first 24 hours after admission, the patient develops respiratory insufficiency after an episode of massive bleeding from his mouth. A computed tomography is performed, which shows a descending thoracic aortic aneurism and signs of aortobronchial fistula. Urgent thoracic endovascular repair was performed. Early symptoms of aortobronchial fistulae are nonspecific which complicates the diagnosis and can lead to treatment delay. The use of bronchoscopy in these cases is controversial.

  20. 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.

  1. Massively Parallel Sequencing Detected a Mutation in the MFN2 Gene Missed by Sanger Sequencing Due to a Primer Mismatch on an SNP Site.

    PubMed

    Neupauerová, Jana; Grečmalová, Dagmar; Seeman, Pavel; Laššuthová, Petra

    2016-05-01

    We describe a patient with early onset severe axonal Charcot-Marie-Tooth disease (CMT2) with dominant inheritance, in whom Sanger sequencing failed to detect a mutation in the mitofusin 2 (MFN2) gene because of a single nucleotide polymorphism (rs2236057) under the PCR primer sequence. The severe early onset phenotype and the family history with severely affected mother (died after delivery) was very suggestive of CMT2A and this suspicion was finally confirmed by a MFN2 mutation. The mutation p.His361Tyr was later detected in the patient by massively parallel sequencing with a gene panel for hereditary neuropathies. According to this information, new primers for amplification and sequencing were designed which bind away from the polymorphic sites of the patient's DNA. Sanger sequencing with these new primers then confirmed the heterozygous mutation in the MFN2 gene in this patient. This case report shows that massively parallel sequencing may in some rare cases be more sensitive than Sanger sequencing and highlights the importance of accurate primer design which requires special attention.

  2. Massive Hemoptysis.

    PubMed

    Rali, Parth; Gandhi, Viral; Tariq, Cheema

    2016-01-01

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

  3. Surgical treatment of a massive bilateral pulmonary embolus due to an entrapped thrombus in a patent foramen ovale: a case report.

    PubMed

    Prifti, Edvin; Ademaj, Fadil; Baboci, Arben; Doko, Albana; Teferici, Daniela

    2015-03-04

    Entrapped thrombus in a patent foramen ovale is a rare form of right heart thromboembolism. Various treatments have been used, such as anti-coagulation and thrombolytic therapy, vena cava filter, percutaneous thrombectomy and surgical embolectomy. A 60-year-old Kosovan woman was admitted to our hospital with a massive bilateral pulmonary thromboembolism, entrapped thrombus in the patent foramen ovale and severe right ventricular dysfunction. The patient underwent on-pump beating-heart removal of the intracardiac thrombus and bilateral pulmonary embolectomy with the use of a Fogarty catheter. The patient's post-operative course was uneventful. In this report, we describe for the first time in this pathology, to the best of our knowledge, a surgical strategy that seems to offer an excellent outcome in patients with severe right ventricular dysfunction. The chosen surgical technique, consisting of on-pump open beating-heart surgery, is a unique procedure in the treatment of an acute pulmonary thromboembolism and entrapped thrombus in a patent foramen ovale.

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

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

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

  5. 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.

  6. The Discovery of Periodic Modulations in the Optical Spectra of Galaxies, Possibly due to Ultrarapid Light Bursts from Their Massive Central Black Holes

    NASA Astrophysics Data System (ADS)

    Borra, Ermanno F.

    2013-09-01

    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 10-13 s, but other causes may be possible. We investigate the hypothesis that the modulation is generated by the Fourier transform of spectral lines, but conclude that this hypothesis is not valid. Although the light burst suggestion implies absurdly high temperatures, it is supported by the fact that the Crab pulsar also has extremely short unresolved pulses (<0.5 ns) that imply similarly high temperatures. Furthermore, the radio spectrum of the Crab pulsar also has spectral bands similar to those that have been detected. Finally, decreasing the signal-to-noise threshold of detection gives results consistent with beamed signals having a small beam divergence, as expected from non-thermal sources that send a jet, like those seen in pulsars. Considering that galaxy centers contain massive black holes, exotic black hole physics may be responsible for the spectral modulation. However, at this stage, this idea is only a hypothesis to be confirmed with further work.

  7. Is the coexistence of mutations in the genes of factor V and MTHFR a predisposing factor for massive skin necrosis due to loxoscelism?

    PubMed

    Mandel, Y; Grotto, I; Gdalevich, M; Mimouni, D; Ashkenazi, I; Haviv, J; Shpilberg, O

    1998-01-01

    A 28-year-old previously healthy man was diagnosed as having an extensive necrotic lesion of his calf due to loxoscelism. One year later he was diagnosed as having co-inheritance of mutations in factor V and methyl tetrahydrofolate reductase (MTHFR). This is the first report of a possible etiologic connection between loxoscelism necrotic lesions and thrombogenic diseases.

  8. 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

  9. Brain death due to abdominal compartment syndrome caused by massive venous bleeding in a patient with a stable pelvic fracture: report of a case.

    PubMed

    Hagiwara, Akiyoshi; Fukushima, Hideki; Inoue, Tetsuya; Murata, Atsuo; Shimazaki, Shuji

    2004-01-01

    We report a rare case in which abdominal compartment syndrome resulting from venous hemorrhaging developed in a patient with stable pelvic fractures, resulting in a fatal outcome. An 84-year-old man with mild pelvic fractures developed hypovolemic shock and underwent transcatheter arterial embolization. He became hemodynamically stable after the procedure, but became hypotensive for the second time 11 h after admission. Urinary bladder pressure rose to 32 mmHg from 4-7 mmHg. Rebleeding from the pelvis with the development of abdominal compartment syndrome was suspected. Repeated transcatheter arterial embolization and laparotomy were performed; however, 1 min into the procedure, both pupils symmetrically dilated and the light reflex disappeared. This case suggests that brain death can sometimes occur due to abdominal compartment syndrome.

  10. 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.

  11. 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

  12. 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.

  13. Massive ascites of unknown origin

    PubMed Central

    Yuan, Shi-Min

    2014-01-01

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

  14. Occurrence of pneumomediastinum due to dental procedures.

    PubMed

    Aslaner, Mehmet Ali; Kasap, Gül Nihal; Demir, Cihat; Akkaş, Meltem; Aksu, Nalan M

    2015-01-01

    The occurrence of pneumomediastinum and massive subcutaneous emphysema due to dental procedures is quite rare. We present a case of pneumomediastinum and massive subcutaneous emphysema that occurred during third molar tooth extraction with air-turbine handpiece.

  15. 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.

  16. 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.

  17. 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.

  18. Chronic pneumonia due to Klebsiella oxytoca mimicking pulmonary tuberculosis.

    PubMed

    Gera, Kamal; Roshan, Rahul; Varma-Basil, Mandira; Shah, Ashok

    2015-01-01

    Klebsiella species infrequently cause acute community acquired pneumonia (CAP). The chronic form of the disease caused by K. pneumoniae (Friedlander's bacillus) was occasionally seen in the pre-antibiotic era. K. oxytoca is a singularly uncommon cause of CAP. The chronic form of the disease caused by K. oxytoca has been documented only once before. A 50-year-old immunocompetent male smoker presented with haemoptysis for 12 months. Imaging demonstrated a cavitary lesion in the right upper lobe with emphysematous changes. Sputum stains and cultures for Mycobacterium tuberculosis were negative. However, three sputum samples for aerobic culture as well as bronchial aspirate cultured pure growth of K. oxytoca. A diagnosis of chronic pneumonia due to K. oxytoca was established and with appropriate therapy, the patient was largely asymptomatic. The remarkable clinical and radiological similarity to pulmonary tuberculosis can result in patients with chronic Klebsiella pneumonia erroneously receiving anti-tuberculous therapy.

  19. Massive Oral Decoding.

    ERIC Educational Resources Information Center

    Janicke, Eugene M.

    1981-01-01

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

  20. Massive pulmonary embolus without hypoxemia.

    PubMed

    Baird, J Scott; Greene, Anne; Schleien, Charles L

    2005-09-01

    To describe a patient who had been taking ibuprofen for 3 days before the diagnosis of a massive pulmonary embolus without hypoxemia. Institutional review board-approved case report. Pediatric intensive care unit. A 16-yr-old male with a history of supraventricular tachycardia. The patient underwent an electrophysiology study and developed mild shortness of breath and then chest pain 2 and 4 days later, respectively. He took ibuprofen for 3 days. Evaluation 1 wk following the procedure revealed dyspnea and tachycardia. Arterial blood gas in room air was significant for hypocarbia without hypoxemia (Pao2, 108 mm Hg; Paco2, 28 mm Hg). Ventilation perfusion scan and computed axial tomography with intravenous contrast were consistent with a massive pulmonary embolus and left external iliac vein thrombus. He received anticoagulation, thrombolysis, a stent in the left iliac vein, and a filter in the inferior vena cava. Perfusion gradually improved and he was discharged home on oral anticoagulation. The absence of hypoxemia (including a normal alveolar-arterial oxygen difference) in our patient with a massive pulmonary embolus may have been related to cyclooxygenase inhibition due to ibuprofen, with improvement in ventilation-perfusion mismatch.

  1. 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.

  2. Massive Stars in Interactive Binaries

    NASA Astrophysics Data System (ADS)

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

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

  3. Growth of massive galaxies through cosmic time

    NASA Astrophysics Data System (ADS)

    Peralta de Arriba, Luis

    2016-07-01

    The discovery that massive galaxies are on average more compact in the primitive Universe has shown the importance of the mechanisms which are growing galaxies in size with cosmic time. A better understanding of the characteristics of these compact objects will give us clues about the nature of the mechanism which is contributing to the growth of massive galaxies. In the first part of this thesis we investigated the discrepancy between dynamical and stellar masses in massive compact early-type galaxies. We obtained velocity dispersions at different redshifts using our own observations with the GTC telescope as well as stacked spectra from a public survey built with the Keck II telescope. Our findings indicate that this discrepancy scales with galaxy compactness, but it does not correlate with redshift. These results lead us to interpret the discrepancy between these two mass estimators as a violation of the homology hypothesis assumed in the computation of dynamical masses, i.e. massive compact galaxies are not self-similar objects to normal-sized massive galaxies. The next step of our research was to guess what constraints on the evolutionary mechanisms of massive galaxies are implied by this non-homology. We find that galaxies populate a plane in the stellar mass-effective radius-velocity dispersion space, and we analyse the constraints that it means on a generic mechanism. Furthermore, we check that these constraints are compatible with simulations of the growth of early-type massive galaxies due to mergers. Finally we addressed the question of which is the best environment for looking for relic galaxies, i.e. old galaxies which have not suffered the size evolution. We find that they prefer dense environments. Comparing our observational results with simulations, we obtain an agreement between both. The most popular way to explain growth of massive galaxies is the accretion of galaxy satellites through mergers. The global conclusion of this thesis is that all

  4. Resummation of Massive Gravity

    SciTech Connect

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

    2011-06-10

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

  5. Supertwistors and massive particles

    SciTech Connect

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

    2014-07-15

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

  6. Massively Redundant Electromechanical Actuators

    DTIC Science & Technology

    2014-08-30

    date of determination). DoD Controlling Office is (insert controlling DoD office). "Massively Redundant Electromechanical Actuators" August... electromechanical systems) processes are used to manufacture reliable and reproducible stators and sliders for the actuators. These processes include

  7. 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…

  8. Recovery From Giant Eruptions in Massive Stars

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  9. Massive edema of the ovary associated with androgenic manifestations.

    PubMed

    Siller, B S; Gelder, M S; Alvarez, R D; Partridge, E E

    1995-11-01

    Massive ovarian edema is a rare tumor-like condition of the ovary characterized by marked enlargement of one or both ovaries due to marked accumulation of edema fluid in the ovarian stroma. This paper reviews the literature on massive ovarian edema and presents a case associated with androgenic manifestations.

  10. SEDs of massive protostars

    NASA Astrophysics Data System (ADS)

    McKee, Christopher F.; Chakrabarti, Sukanya

    Massive protostars are generally enshrouded in dust, so that most of their radiation emerges in the far infrared. For protostars embedded in opaque, spherical cores, the spectral energy distribution (SED) is determined by two distance-independent parameters, the luminosity-to-mass ratio, L/M_c, and the surface density of the core, Σ=M_c/(π R_c^2), where R_c is the radius of the core. Chakrabarti & McKee (2005a) have derived an approximate analytic expression for the SED that agrees well with numerical results. It is generally not possible to infer the power-law of the density from the SED of a massive protostar. Masses and accretion rates are inferred for several well-studied sources.

  11. 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.

  12. Phases of massive gravity

    NASA Astrophysics Data System (ADS)

    Dubovsky, Sergei L.

    2004-10-01

    We systematically study the most general Lorentz-violating graviton mass invariant under three-dimensional Eucledian group. We find that at general values of mass parameters the massive graviton has six propagating degrees of freedom, and some of them are ghosts or lead to rapid classical instabilities. However, there is a number of different regions in the mass parameter space where massive gravity is described by a consistent low-energy effective theory with cutoff ~ (mMPl)1/2. This theory is free of rapid instabilities and vDVZ discontinuity. Each of these regions is characterized by certain fine-tuning relations between mass parameters, generalizing the Fierz Pauli condition. In some cases the required fine-tunings are consequences of the existence of the subgroups of the diffeomorphism group that are left unbroken by the graviton mass. We found two new cases, when the resulting theories have a property of UV insensitivity, i.e. remain well behaved after inclusion of arbitrary higher dimension operators without assuming any fine-tunings among the coefficients of these operators, besides those enforced by the symmetries. These theories can be thought of as generalizations of the ghost condensate model with a smaller residual symmetry group. We briefly discuss what kind of cosmology can one expect in massive gravity and argue that the allowed values of the graviton mass may be quite large, affecting growth of primordial perturbations, structure formation and, perhaps, enhancing the backreaction of inhomogeneities on the expansion rate of the Universe.

  13. Massively Parallel Genetics.

    PubMed

    Shendure, Jay; Fields, Stanley

    2016-06-01

    Human genetics has historically depended on the identification of individuals whose natural genetic variation underlies an observable trait or disease risk. Here we argue that new technologies now augment this historical approach by allowing the use of massively parallel assays in model systems to measure the functional effects of genetic variation in many human genes. These studies will help establish the disease risk of both observed and potential genetic variants and to overcome the problem of "variants of uncertain significance." Copyright © 2016 by the Genetics Society of America.

  14. Massive star forming environments

    NASA Astrophysics Data System (ADS)

    Devine, Kathryn Elizabeth

    2010-12-01

    We present a study of the earliest stages of massive star formation, in which we focus on Infrared Dark Clouds (IRDCs) and young massive clusters. We present Very Large Array spectral line observations of ammonia (NH 3) and CCS toward four IRDCs. The NH3 lines provide diagnostics of the temperature and density structure within IRDCs. Based upon the NH 3 column density, IRDCs have masses of ˜ 103 to 10 4 M⊙ . We detect twenty NH3 clumps within four IRDCs, with radii < 0.3 pc and masses ˜ 102 to 103 M⊙ . A majority of the clumps are associated with signatures of star formation: 24 mum emission, H2O masers, 8 GHz continuum emission, and/or outflows. The physical properties of the clumps are consistent with massive cluster progenitors. From the NH3 emission we also find distinct velocity components, or "subclouds", within each IRDC. Although they appear ubiquitous in IRDCs, subclouds have not previously been reported. Subclouds may represent an intermediate stage of molecular cloud fragmentation, between filamentary structure and clump formation. The spatial distribution of the CCS and NH3 emission is generally anti-correlated, with the NH 3 predominantly in the high-density clumps, and CCS in lower-density gas. This spatial distribution may be explained by chemical evolution models for star forming gas, where in chemically young clouds with recently disrupted gas CCS forms quickly. In early clump formation CCS is abundant and in the centers of more evolved star forming clumps CCS is depleted. Near infrared observations of three embedded massive star forming regions are presented from the Near Infrared Imager (NIRIM) camera on the 3.5 m WIYN telescope. We report J, H, and K' band photometry in the clusters AFGL437, AFGL5180, and AFGL5142 and use these results to probe the stellar populations, extinction, and ages of the clusters. We find that all three clusters suffer significant extinction (AK ˜1), have ages ≤ 5 Myr, and are actively forming stars. We

  15. 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.

  16. 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.

  17. Minimal massive 3D gravity

    NASA Astrophysics Data System (ADS)

    Bergshoeff, Eric; Hohm, Olaf; Merbis, Wout; Routh, Alasdair J.; Townsend, Paul K.

    2014-07-01

    We present an alternative to topologically massive gravity (TMG) with the same ‘minimal’ bulk properties; i.e. a single local degree of freedom that is realized as a massive graviton in linearization about an anti-de Sitter (AdS) vacuum. However, in contrast to TMG, the new ‘minimal massive gravity’ has both a positive energy graviton and positive central charges for the asymptotic AdS-boundary conformal algebra.

  18. Are All Magnetic White Dwarf Stars Massive?

    NASA Astrophysics Data System (ADS)

    Nitta, A.; Kepler, S. O.; Kulebi, B.; Koester, D.; Kleinman, S. J.; Winget, D. E.; Castanheira, B. G.; Corsico, A. H.

    2017-03-01

    We obtained follow-up spectra on 25 white dwarf stars identified in our white dwarf catalog of Sloan Digital Sky Survey (SDSS) as massive or magnetic. We identified over 300 magnetic white dwarf stars from SDSS with some uncertainties due to the low S/N of the spectra. With much higher S/N Gemini data, our sample should be able to help us confirm accuracy of our determinations. We present here our results so far from the follow up observations.

  19. 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.

  20. Massive acute arsenic poisonings.

    PubMed

    Lech, Teresa; Trela, Franciszek

    2005-07-16

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

  1. Magnetospheres of massive stars

    NASA Astrophysics Data System (ADS)

    Küker, M.

    We study the interaction of line-driven winds from massive stars with the magnetic field rooted in these stars by carrying out numerical simulations using the Nirvana MHD code in 2D in spherical polar coordinates. The code's adaptive mesh refinement feature allows high spatial resolution across the whole simulation box. We study both O and Wolf-Rayet stars for a range of magnetic field strengths from weak to strong as measured by the confinement parameter. For weak fields our simulations show that the initially dipolar field opens up far away from the star and a thin disk-like structure forms in the equatorial plane of the magnetic field. For stronger fields the disk is disrupted close to the stellar surface and closed field lines persist at low latitudes. For very strong fields a pronounced magnetosphere forms where the gas is forced to move along the field lines and eventually falls back to the stellar surface.

  2. 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.

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

    PubMed

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

    2013-11-01

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

  4. 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.

  5. Massive soliton stars

    NASA Astrophysics Data System (ADS)

    Chiu, Hong-Yee

    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.

  6. 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.

  7. 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.

  8. Benchmarking massively parallel architectures

    SciTech Connect

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

    1993-01-01

    The purpose of this paper is to summarize some initial experiences related to measuring the performance of massively parallel processors (MPPs) at Los Alamos National Laboratory (LANL). Actually, the range of MPP architectures the authors have used is rather limited, being confined mostly to the Thinking Machines Corporation (TMC) Connection Machine CM-2 and CM-5. Some very preliminary work has been carried out on the Kendall Square KSR-1, and efforts related to other machines, such as the Intel Paragon and the soon-to-be-released CRAY T3D are planned. This paper will concentrate more on methodology rather than discuss specific architectural strengths and weaknesses; the latter is expected to be the subject of future reports. MPP benchmarking is a field in critical need of structure and definition. As the authors have stated previously, such machines have enormous potential, and there is certainly a dire need for orders of magnitude computational power over current supercomputers. However, performance reports for MPPs must emphasize actual sustainable performance from real applications in a careful, responsible manner. Such has not always been the case. A recent paper has described in some detail, the problem of potentially misleading performance reporting in the parallel scientific computing field. Thus, in this paper, the authors briefly offer a few general ideas on MPP performance analysis.

  9. 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.

  10. Zinc toxicity following massive coin ingestion.

    PubMed

    Bennett, D R; Baird, C J; Chan, K M; Crookes, P F; Bremner, C G; Gottlieb, M M; Naritoku, W Y

    1997-06-01

    This is the first reported case of human fatality associated with zinc intoxication following a massive ingestion of coins. Four hundred and sixty-one coins were removed form the gastrointestinal tract of a schizophrenic patient during the course of hospitalization. Many of the post-1981 pennies, which consist primarily of zinc, showed severe corrosion due to their prolonged contact with acidic gastric juice. The patient presented with clinical manifestations consistent with the local corrosive as well as systemic effects of zinc intoxication and died 40 days after admission with multi-system organ failure. Tissue samples of the kidneys, pancreas, and liver obtained at autopsy revealed acute tubular necrosis, mild fibrosis, and acute massive necrosis, respectively, and contained high levels of zinc. The overall effects of zinc intoxication on the various organ systems, possible hematological derangement, and the impairment of copper absorption as well as the outcome with treatment are discussed.

  11. 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.

  12. 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.

  13. Parallel rendering techniques for massively parallel visualization

    SciTech Connect

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

    1995-07-01

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

  14. The Destructive Birth of Massive Stars and Massive Star Clusters

    NASA Astrophysics Data System (ADS)

    Rosen, Anna; Krumholz, Mark; McKee, Christopher F.; Klein, Richard I.; Ramirez-Ruiz, Enrico

    2017-01-01

    Massive stars play an essential role in the Universe. They are rare, yet the energy and momentum they inject into the interstellar medium with their intense radiation fields dwarfs the contribution by their vastly more numerous low-mass cousins. Previous theoretical and observational studies have concluded that the feedback associated with massive stars' radiation fields is the dominant mechanism regulating massive star and massive star cluster (MSC) formation. Therefore detailed simulation of the formation of massive stars and MSCs, which host hundreds to thousands of massive stars, requires an accurate treatment of radiation. For this purpose, we have developed a new, highly accurate hybrid radiation algorithm that properly treats the absorption of the direct radiation field from stars and the re-emission and processing by interstellar dust. We use our new tool to perform a suite of three-dimensional radiation-hydrodynamic simulations of the formation of massive stars and MSCs. For individual massive stellar systems, we simulate the collapse of massive pre-stellar cores with laminar and turbulent initial conditions and properly resolve regions where we expect instabilities to grow. We find that mass is channeled to the massive stellar system via gravitational and Rayleigh-Taylor (RT) instabilities. For laminar initial conditions, proper treatment of the direct radiation field produces later onset of RT instability, but does not suppress it entirely provided the edges of the radiation-dominated bubbles are adequately resolved. RT instabilities arise immediately for turbulent pre-stellar cores because the initial turbulence seeds the instabilities. To model MSC formation, we simulate the collapse of a dense, turbulent, magnetized Mcl = 106 M⊙ molecular cloud. We find that the influence of the magnetic pressure and radiative feedback slows down star formation. Furthermore, we find that star formation is suppressed along dense filaments where the magnetic field is

  15. 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.

  16. 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.

  17. Massive gravity in three dimensions.

    PubMed

    Bergshoeff, Eric A; Hohm, Olaf; Townsend, Paul K

    2009-05-22

    A particular higher-derivative extension of the Einstein-Hilbert action in three spacetime dimensions is shown to be equivalent at the linearized level to the (unitary) Pauli-Fierz action for a massive spin-2 field. A more general model, which also includes "topologically-massive" gravity as a special case, propagates the two spin-2 helicity states with different masses. We discuss the extension to massive N-extended supergravity, and we present a "cosmological" extension that admits an anti-de Sitter vacuum.

  18. Simulating A Massive, Mobile Structure

    NASA Technical Reports Server (NTRS)

    Fantasia, Peter M.; Kahn, Jon B.; Sprague, Benny B.

    1990-01-01

    Simulator replicates, kinematically and dynamically, mating of large, massive mobile structure with similarly large and massive fixed structure. Developed for testing berthing-and-latching mechanism. Fixed section holds active berthing-and-latching mechanism and its motor control system with optical encoder to maintain synchronization among four latches in mechanism. Tripodal load-cell network gathers data on load history of berthing operation, and infrared tracking system including light-emitting diodes produces data for position history.

  19. Topologically massive gravity and Ricci-Cotton flow

    NASA Astrophysics Data System (ADS)

    Lashkari, Nima; Maloney, Alexander

    2011-05-01

    We consider topologically massive gravity (TMG), which is three-dimensional general relativity with a cosmological constant and a gravitational Chern-Simons term. When the cosmological constant is negative the theory has two potential vacuum solutions: anti-de Sitter space and warped anti-de Sitter space. The theory also contains a massive graviton state which renders these solutions unstable for certain values of the parameters and boundary conditions. We study the decay of these solutions due to the condensation of the massive graviton mode using Ricci-Cotton flow, which is the appropriate generalization of Ricci flow to TMG. When the Chern-Simons coupling is small the AdS solution flows to warped AdS by the condensation of the massive graviton mode. When the coupling is large the situation is reversed, and warped AdS flows to AdS. Minisuperspace models are constructed where these flows are studied explicitly.

  20. Body contouring following massive weight loss.

    PubMed

    Taylor, Jesse; Shermak, Michele

    2004-09-01

    Obesity and its associated medical morbidities carry substantial health risk. While massive weight loss allows improvement in health status and lifestyle, physical sequelae due to symptomatic skin redundancy still require treatment. Areas affected include the arms, breasts, abdomen, back, and thighs. After open gastric bypass, patients often have poor abdominal support and incisional hernias. To completely address the treatment of patients following massive weight loss, body contouring procedures are performed, often in one stage and tailored to each patient, to rid the functional and esthetic impairment from skin redundancy. This retrospective study includes 30 patients treated from March 1998 to August 2002 by a single surgeon at an academic hospital. Average weight loss had been 71 kg, and average weight and BMI at the time of contouring surgery were 98.6 kg and 33 kg/m2 respectively. Procedures included abdominal panniculectomy, thighlift, backlift, brachioplasty, mastopexy and incisional hernia repair, performed either alone or in combination. Average weight of resected tissue was 5.9 kg. Average length of stay was 3 days. Complications included seroma, wound breakdown, hematoma requiring surgical drainage, and lymphocele after brachioplasty. One patient died of a pulmonary embolus within weeks after surgery. Patients requiring surgical skin excision after massive weight loss for functional and/or esthetic reasons are challenging, and require individualized approaches with intensive follow-up.

  1. [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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  3. 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.

  4. 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

  5. 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.

  6. Phenomenology in minimal theory of massive gravity

    SciTech Connect

    Felice, Antonio De; Mukohyama, Shinji

    2016-04-15

    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.

  7. Parallel Spatiotemporal Spectral Clustering with Massive Trajectory Data

    NASA Astrophysics Data System (ADS)

    Gu, Y. Z.; Qin, K.; Chen, Y. X.; Yue, M. X.; Guo, T.

    2017-09-01

    Massive trajectory data contains wealth useful information and knowledge. Spectral clustering, which has been shown to be effective in finding clusters, becomes an important clustering approaches in the trajectory data mining. However, the traditional spectral clustering lacks the temporal expansion on the algorithm and limited in its applicability to large-scale problems due to its high computational complexity. This paper presents a parallel spatiotemporal spectral clustering based on multiple acceleration solutions to make the algorithm more effective and efficient, the performance is proved due to the experiment carried out on the massive taxi trajectory dataset in Wuhan city, China.

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

    NASA Astrophysics Data System (ADS)

    Altas, Emel; Tekin, Bayram

    2016-01-01

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

  9. Massive transfusion: blood component ratios.

    PubMed

    Lal, Devika S; Shaz, Beth H

    2013-11-01

    This review will address recent developments in the transfusion management of massively transfused trauma patients, focusing on the use of fixed blood component ratios in massive transfusion protocols. The majority of trauma centers have migrated from laboratory-based transfusion protocols to massive transfusion protocols with fixed blood component ratios. These protocols with red blood cell : plasma : platelet ratio of 1 : 1 : 1 are associated with improved survival in severely injured patients. However, alternate ratios have also demonstrated improved survival. Thus, the optimal ratio has not been determined. In addition, the use of medications, such as antifibrinolytics, and point of care testing, such as thromboelastography, are increasingly being used as part of massive transfusion protocols to adjust transfusion therapy and decrease bleeding. However, their optimal integration has yet to be determined. Massive transfusion protocols with fixed ratios of red blood cells to plasma and platelets have improved survival in both civilian and military trauma patients. Continued studies of ratios as well as integration of other therapies and testing are ongoing in order to continue to improve patient outcome.

  10. Massive transfusion in paediatric and adolescent trauma patients: incidence, patient profile, and outcomes prior to a massive transfusion protocol.

    PubMed

    Livingston, Michael Hobbs; Singh, Supriya; Merritt, Neil Howard

    2014-09-01

    The purpose of this study was to quantify the incidence, patient profile, and outcomes associated with massive transfusion in paediatric trauma patients prior to establishing a massive transfusion protocol. We performed a retrospective review of paediatric trauma patients treated at London Heath Sciences Centre between January 1, 2006, and December 31, 2011. Inclusion criteria were Injury Severity Score (ISS) greater than 12 and age less than 18 years. 435 patients met the inclusion criteria. Three hundred and fifty-six (82%) did not receive packed red blood cells in the first 24h, 66 (15%) received a non-massive transfusion (<40mL/kg), and 13 (3%) received a massive transfusion (>40mL/kg). Coagulopathy of any kind was more common in massive transfusion (11/13; 85%) than non-massive (32/66; 49%) (p=0.037). Hyperkalemia (18% versus 23%; p=0.98) and hypocalcemia (41% versus 46%; p=1.00) were similar in both groups. Of the 13 massively transfused patients, 9 had multisystem injuries due to a motor vehicle collision, 3 had non-accidental head injuries requiring surgical evacuation, and 1 had multiple stab wounds. In the absence of a massive transfusion protocol, only 8 of the 13 patients received both fresh frozen plasma and platelets in the first 24h. Massive transfusion occurred in patients from across the age spectrum and was associated with severe injuries (mean ISS=33), a higher incidence of severe head injuries (92%), longer hospital stay (mean=36 days), and increased mortality (38%). This study is the first to describe the incidence, complications, and outcomes associated with massive transfusion in paediatric trauma patients prior to a massive transfusion protocol. Massive transfusion occurred in 3% of patients and was associated with coagulopathy and poor outcomes. Protocols are needed to ensure that resuscitation occurs in a coordinated fashion and that patients are given appropriate amounts of fresh frozen plasma, platelets, and cryoprecipitate. Copyright

  11. 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

  12. Positive signs in massive gravity

    SciTech Connect

    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 island 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.

  13. 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.

  14. 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.

  15. Processing massive datasets in genomics

    NASA Astrophysics Data System (ADS)

    Artiguenave, F.

    2011-02-01

    Life science researches have been profoundly impacted by technological advances allowing faster and cheaper DNA sequencing. Opening a wide range of applications in medical and biology, the last generation sequencing platforms raised new challenges, in particular in processing, analysing and interpreting massive data. In this talk, the growing role of bioinformatics will be illustrated by providing some figures about genome sequencing and others applications aimed at unravelling biological mechanisms. Methods to gather insights from massive amount of data will be illustrated by the genome annotation process, by which genes are identified in the genome sequence.

  16. Massive photons and Lorentz violation

    NASA Astrophysics Data System (ADS)

    Cambiaso, Mauro; Lehnert, Ralf; Potting, Robertus

    2012-04-01

    All quadratic translation- and gauge-invariant photon operators for Lorentz breakdown are included into the Stueckelberg Lagrangian for massive photons in a generalized Rξ gauge. The corresponding dispersion relation and tree-level propagator are determined exactly, and some leading-order results are derived. The question of how to include such Lorentz-violating effects into a perturbative quantum-field expansion is addressed. Applications of these results within Lorentz-breaking quantum-field theories include the regularization of infrared divergences as well as the free propagation of massive vector bosons.

  17. Dynamics of Massive Atmospheres

    NASA Astrophysics Data System (ADS)

    Chemke, Rei; Kaspi, Yohai

    2017-08-01

    The many recently discovered terrestrial exoplanets are expected to hold a wide range of atmospheric masses. Here the dynamic-thermodynamic effects of atmospheric mass on atmospheric circulation are studied using an idealized global circulation model by systematically varying the atmospheric surface pressure. On an Earth analog planet, an increase in atmospheric mass weakens the Hadley circulation and decreases its latitudinal extent. These changes are found to be related to the reduction of the convective fluxes and net radiative cooling (due to the higher atmospheric heat capacity), which, respectively, cool the upper troposphere at mid-low latitudes and warm the troposphere at high latitudes. These together decrease the meridional temperature gradient, tropopause height and static stability. The reduction of these parameters, which play a key role in affecting the flow properties of the tropical circulation, weakens and contracts the Hadley circulation. The reduction of the meridional temperature gradient also decreases the extraction of mean potential energy to the eddy fields and the mean kinetic energy, which weakens the extratropical circulation. The decrease of the eddy kinetic energy decreases the Rhines wavelength, which is found to follow the meridional jet scale. The contraction of the jet scale in the extratropics results in multiple jets and meridional circulation cells as the atmospheric mass increases.

  18. Fast, Massively Parallel Data Processors

    NASA Technical Reports Server (NTRS)

    Heaton, Robert A.; Blevins, Donald W.; Davis, ED

    1994-01-01

    Proposed fast, massively parallel data processor contains 8x16 array of processing elements with efficient interconnection scheme and options for flexible local control. Processing elements communicate with each other on "X" interconnection grid with external memory via high-capacity input/output bus. This approach to conditional operation nearly doubles speed of various arithmetic operations.

  19. 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.

  20. Massive scrotal edema as a complication of abdominoplasty.

    PubMed

    Girardeau, J T; Young, V L

    1985-10-01

    Massive scrotal edema is an unreported complication of abdominoplasty. This patient's postoperative decompensation of medial thigh and scrotal lymphatic return may well have been due to an occult lymphedema tarda or previously compromised lymphatics from the fibrosis of venous stasis disease and obesity.

  1. 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…

  2. Decision-making in massive rotator cuff tear.

    PubMed

    Thès, André; Hardy, Philippe; Bak, Klaus

    2015-02-01

    Treatment of massive rotator cuff tears has developed over many years ranging from conservative treatment to open and arthroscopic repair, muscle transfers and reversed arthroplasty. The evolution of more advanced techniques in arthroscopic repair has changed the treatment approach and improved the prognosis for functional outcome despite low healing rates. Due to this rapid development, our evidence-based knowledge today is mainly founded in Level 3 and Level 4 studies. Based on the literature, the current knowledge on treatment of symptomatic massive rotator cuff tears is proposed in an algorithm. Level of evidence V.

  3. QUARK MATTER IN MASSIVE COMPACT STARS

    SciTech Connect

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

    2011-10-10

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

  4. 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.

  5. 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.

  6. Massive binary stars as a probe of massive star formation

    NASA Astrophysics Data System (ADS)

    Kiminki, Daniel C.

    2010-10-01

    Massive stars are among the largest and most influential objects we know of on a sub-galactic scale. Binary systems, composed of at least one of these stars, may be responsible for several types of phenomena, including type Ib/c supernovae, short and long gamma ray bursts, high-velocity runaway O and B-type stars, and the density of the parent star clusters. Our understanding of these stars has met with limited success, especially in the area of their formation. Current formation theories rely on the accumulated statistics of massive binary systems that are limited because of their sample size or the inhomogeneous environments from which the statistics are collected. The purpose of this work is to provide a higher-level analysis of close massive binary characteristics using the radial velocity information of 113 massive stars (B3 and earlier) and binary orbital properties for the 19 known close massive binaries in the Cygnus OB2 Association. This work provides an analysis using the largest amount of massive star and binary information ever compiled for an O-star rich cluster like Cygnus OB2, and compliments other O-star binary studies such as NGC 6231, NGC 2244, and NGC 6611. I first report the discovery of 73 new O or B-type stars and 13 new massive binaries by this survey. This work involved the use of 75 successful nights of spectroscopic observation at the Wyoming Infrared Observatory in addition to observations obtained using the Hydra multi-object spectrograph at WIYN, the HIRES echelle spectrograph at KECK, and the Hamilton spectrograph at LICK. I use these data to estimate the spectrophotometric distance to the cluster and to measure the mean systemic velocity and the one-sided velocity dispersion of the cluster. Finally, I compare these data to a series of Monte Carlo models, the results of which indicate that the binary fraction of the cluster is 57 +/- 5% and that the indices for the power law distributions, describing the log of the periods, mass

  7. Topologically massive higher spin gravity

    NASA Astrophysics Data System (ADS)

    Bagchi, Arjun; Lal, Shailesh; Saha, Arunabha; Sahoo, Bindusar

    2011-10-01

    We look at the generalisation of topologically massive gravity (TMG) to higher spins, specifically spin-3. We find a special "chiral" point for the spin-three, analogous to the spin-two example, which actually coincides with the usual spin-two chiral point. But in contrast to usual TMG, there is the presence of a non-trivial trace and its logarithmic partner at the chiral point. The trace modes carry energy opposite in sign to the traceless modes. The logarithmic partner of the traceless mode carries negative energy indicating an instability at the chiral point. We make several comments on the asymptotic symmetry and its possible deformations at this chiral point and speculate on the higher spin generalisation of LCFT2 dual to the spin-3 massive gravity at the chiral point.

  8. Spin-3 topologically massive gravity

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Long, Jiang; Wu, Jun-bao

    2011-11-01

    In this Letter, we study the spin-3 topologically massive gravity (TMG), paying special attention to its properties at the chiral point. We propose an action describing the higher spin fields coupled to TMG. We discuss the traceless spin-3 fluctuations around the AdS3 vacuum and find that there is an extra local massive mode, besides the left-moving and right-moving boundary massless modes. At the chiral point, such extra mode becomes massless and degenerates with the left-moving mode. We show that at the chiral point the only degrees of freedom in the theory are the boundary right-moving graviton and spin-3 field. We conjecture that spin-3 chiral gravity with generalized Brown-Henneaux boundary condition is holographically dual to 2D chiral CFT with classical W3 algebra and central charge cR = 3 l / G.

  9. New branches of massive gravity

    NASA Astrophysics Data System (ADS)

    Comelli, D.; Crisostomi, M.; Koyama, K.; Pilo, L.; Tasinato, G.

    2015-06-01

    The basic building block for Lorentz-invariant and ghost-free massive gravity is the square root of the combination g-1η , where g-1 is the inverse of the physical metric and η is a reference metric. Since the square root of a matrix is not uniquely defined, it is possible to have physically inequivalent potentials corresponding to different branches. We show that around the Minkowski background, the only perturbatively well-defined branch is the potential proposed by de Rham, Gabadadze and Tolley. On the other hand, if Lorentz symmetry is broken spontaneously, other potentials exist with a standard perturbative expansion. We show this explicitly building new Lorentz-invariant, ghost-free massive gravity potentials for theories that in the background preserve rotational invariance but break Lorentz boosts.

  10. Black holes in massive gravity

    NASA Astrophysics Data System (ADS)

    Babichev, Eugeny; Brito, Richard

    2015-08-01

    We review the black hole (BH) solutions of the ghost-free massive gravity theory and its bimetric extension, and outline the main results on the stability of these solutions against small perturbations. Massive (bi)-gravity accommodates exact BH solutions, analogous to those of general relativity (GR). In addition to these solutions, hairy BHs—solutions with no correspondent in GR—have been found numerically, whose existence is a natural consequence of the absence of Birkhoff’s theorem in these theories. The existence of extra propagating degrees of freedom, makes the stability properties of these BHs richer and more complex than those of GR. In particular, the bi-Schwarzschild BH exhibits an unstable spherically symmetric mode, while the bi-Kerr geometry is also generically unstable, both against the spherical mode and against superradiant instabilities. If astrophysical BHs are described by these solutions, the superradiant instability of the Kerr solution imposes stringent bounds on the graviton mass.

  11. Formation of Massive Stars: Theoretical Considerations

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.

    2008-01-01

    This slide presentation reviews theoretical considerations of the formation of massive stars. It addresses the questions that assuming a gravitationally unstable massive clump, how does enough material become concentrated into a sufficiently small volume within a sufficiently short time? and how does the forming massive star influence its immediate surroundings to limit its mass?

  12. Theoretical Considerations of Massive Star Formation

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.

    2006-01-01

    This viewgraph presentation reviews the formation of massive stars. The formation of massive stars is different in many ways from the formation of other stars. The presentation shows the math, and the mechanisms that must be possible for a massive star to form.

  13. Formation of Massive Stars: Theoretical Considerations

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.

    2008-01-01

    This slide presentation reviews theoretical considerations of the formation of massive stars. It addresses the questions that assuming a gravitationally unstable massive clump, how does enough material become concentrated into a sufficiently small volume within a sufficiently short time? and how does the forming massive star influence its immediate surroundings to limit its mass?

  14. Theoretical Considerations of Massive Star Formation

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.

    2006-01-01

    This viewgraph presentation reviews the formation of massive stars. The formation of massive stars is different in many ways from the formation of other stars. The presentation shows the math, and the mechanisms that must be possible for a massive star to form.

  15. Massive gravity on a brane

    SciTech Connect

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

    2003-12-11

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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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".

  3. 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.

  4. Massive Acquision of Asteroid Data.

    NASA Astrophysics Data System (ADS)

    Slobodrian, R. J.

    A massive data acquisition programme based on minirobotic techniques is described. A mother spaceship would transport a load of "minilanders" close to the asteroid belt and direct them to asteroids having a given minimal size. Close to 100 such minilanders with miniprobes and minirobots could be transported by one spaceship. Each would have its own propulsion and guidance system, as well as radio contact with the mother ship. They would anchor on the asteroids and measure physical and composition data. Asteroids often consist of a single valuable element and could be transported, using solar sails, towards the earth's orbit or to a lunar location for utilization.

  5. Solid holography and massive gravity

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  6. 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

  7. Massive Compact Stars as Quark Stars

    NASA Astrophysics Data System (ADS)

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

    2011-03-01

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

  8. 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.

  9. 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.

  10. Increased Understanding of Accretion in Massive YSOs

    NASA Astrophysics Data System (ADS)

    De Wit, Willem-Jan; Caratti, A.; Kraus, S.

    2017-06-01

    That massive stars up to 20Msol form by disk accretion is by now reasonably well established. We will present the latest observational results for the formation of single and multiple massive YSOs. By means of optical interferometry using the newly commissioned instrument Gravity at the VLT-I, we show the discovery of a young, embedded, 170AU-wide binary and is the most massive and most compact accreting young binary to date. We will also present the results of a multi-site multi-epoch follow-up campaign of the first well studied accretion outburst in a massive YSO.

  11. The limiting factors on volcanism on massive stagnant lid planets

    NASA Astrophysics Data System (ADS)

    Höning, D.; Spohn, T.

    2012-04-01

    As the number of discovered exoplanets is increasing, the question whether these planets could harbor life becomes more relevant. Chemoautotrophs, which live from thermal disequilibrium due to volcanic activity, are believed to have been the first organisms on Earth and maybe on planets in general. Furthermore, volcanism influences the atmosphere, and therefore the habitability of the planet. Therefore, we investigate weather volcanism could occur on massive stagnant lid planets in dependence of their mass, age, surface temperature or their relative mantle thickness.

  12. [Massive localized lymphoedema (MLL) in the mons pubis].

    PubMed

    Bognár, Gábor; Novák, András; István, Gábor

    2014-08-01

    Massive localized lymphoedema (MLL) is a relatively frequent complication in obesity. MLL is present as a giant swelling and associated with characteristic skin changes. Due to the pathologic and morphologic similarity to sarcoma, MLL is also called "pseudosarcoma". MLL can degenerate into angiosarcoma without surgery. We present a case of MLL of the mons pubis in a 54-year-old man with a BMI of 48.6.

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

    PubMed

    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.

  14. 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

  15. Observational studies of regions of massive star formation

    NASA Astrophysics Data System (ADS)

    Cooper, Heather Danielle Blythe

    2013-03-01

    Massive stars have a profound influence on their surroundings. However, relatively little is known about their formation. The study of massive star formation is hindered by a lack of observational evidence, primarily due to difficulties observing massive stars at early stages in their development. The Red MSX Source survey (RMS survey) is a valuable tool with which to address these issues. Near-infrared H- and K-band spectra were taken for 247 candidate massive young stellar objects (MYSOs), selected from the RMS survey. 195 (∼80%) of the targets are YSOs, of which 131 are massive YSOs (LBOL>5E3L⊙, M>8 M⊙). This is the largest spectroscopic study of massive YSOs to date. This study covers minimally obscured objects right through to very red, dusty sources. Almost all YSOs show some evidence for emission lines, though there is a wide variety of observed properties, with HI, H2 Fe II, and CO among the most commonly observed lines. Evidence for disks and outflows was frequently seen. Comparisons of Brγ and H2 emission with low mass YSOs suggest that the emission mechanism for these lines is the same for low-, intermediate-, and high-mass YSOs, i.e. high-mass YSOs appear to resemble scaled-up versions of low-mass YSOs. It was found that the YSOs form an evolutionary sequence, based on their spectra, consistent with the existing theoretical models. Type I YSOs have strong H2 emission, no ionized lines, and are redder than the other two subtypes. As such, these are considered to be the youngest sources. The Type III sources are bluest, and therefore considered to be the oldest subtype. They have strong H I lines and fluorescent Fe II 1.6878 μm emission. They may also have weak H2 emission. Type III sources may even be beginning to form a mini-H II region. XSHOOTER data from 10 Herbig Be stars were analysed. The evidence suggests that winds and disks are common among Herbig stars, as they are among their main sequence classical Be star counterparts. Line

  16. No preferential spatial distribution for massive stars expected from their formation

    NASA Astrophysics Data System (ADS)

    Parker, Richard J.; Dale, James E.

    2017-09-01

    We analyse N-body and smoothed particle hydrodynamic (SPH) simulations of young star-forming regions to search for differences in the spatial distributions of massive stars compared to lower mass stars. The competitive accretion theory of massive star formation posits that the most massive stars should sit in deeper potential wells than lower mass stars. This may be observable in the relative surface density or spatial concentration of the most massive stars compared to other lower mass stars. Massive stars in cool-collapse N-body models do end up in significantly deeper potentials and are mass segregated. However, in models of warm (expanding) star-forming regions, whilst the massive stars do come to be in deeper potentials than average stars, they are not mass segregated. In the purely hydrodynamical SPH simulations, the massive stars do come to reside in deeper potentials, which is due to their runaway growth. However, when photoionization and stellar winds are implemented in the simulations, these feedback mechanisms regulate the mass of the stars and disrupt the inflow of gas into the clouds' potential wells. This generally makes the potential wells shallower than in the control runs, and prevents the massive stars from occupying deeper potentials. This in turn results in the most massive stars having a very similar spatial concentration and surface density distribution to lower mass stars. Whilst massive stars do form via competitive accretion in our simulations, this rarely translates to a different spatial distribution and so any lack of primordial mass segregation in an observed star-forming region does not preclude competitive accretion as a viable formation mechanism for massive stars.

  17. 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.

  18. The physics of massive neutrinos

    SciTech Connect

    Gibrat-Debu, F.; Perrier, F.; Kayser, B.

    1988-01-01

    This book explains the physics and phenomenology of massive neutrinos. The authors argue that neutrino mass is not unlikely and consider briefly the search for evidence of this mass in decay processes before they examine the physics and phenomenology of neutrino oscillation. The physics of Majorana neutrinos (neutrinos which are their own antiparticles) is then discussed. Firstly, a number of basic properties of such neutrinos are established without using any field theory. Then the field-theory description of a Majorana particle is introduced and used to treat such processes as neutrinos double beta decay. Finally, there is a treatment of neutrino masses in gauge theories and a derivation of the seesaw relation, which explains why neutrino masses are so small by relating them to the inverse of a large mass scale.

  19. Massively parallel MRI detector arrays.

    PubMed

    Keil, Boris; Wald, Lawrence L

    2013-04-01

    Originally proposed as a method to increase sensitivity by extending the locally high-sensitivity of small surface coil elements to larger areas via reception, the term parallel imaging now includes the use of array coils to perform image encoding. This methodology has impacted clinical imaging to the point where many examinations are performed with an array comprising multiple smaller surface coil elements as the detector of the MR signal. This article reviews the theoretical and experimental basis for the trend towards higher channel counts relying on insights gained from modeling and experimental studies as well as the theoretical analysis of the so-called "ultimate" SNR and g-factor. We also review the methods for optimally combining array data and changes in RF methodology needed to construct massively parallel MRI detector arrays and show some examples of state-of-the-art for highly accelerated imaging with the resulting highly parallel arrays. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. 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.

  1. 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.

  2. Stable massive particles at colliders

    SciTech Connect

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

    2006-11-01

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

  3. Light weakly interacting massive particles

    NASA Astrophysics Data System (ADS)

    Gelmini, Graciela B.

    2017-08-01

    Light weakly interacting massive particles (WIMPs) are dark matter particle candidates with weak scale interaction with the known particles, and mass in the GeV to tens of GeV range. Hints of light WIMPs have appeared in several dark matter searches in the last decade. The unprecedented possible coincidence into tantalizingly close regions of mass and cross section of four separate direct detection experimental hints and a potential indirect detection signal in gamma rays from the galactic center, aroused considerable interest in our field. Even if these hints did not so far result in a discovery, they have had a significant impact in our field. Here we review the evidence for and against light WIMPs as dark matter candidates and discuss future relevant experiments and observations.

  4. 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.

  5. 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

  6. Derivative couplings in massive bigravity

    SciTech Connect

    Gao, Xian; Heisenberg, Lavinia E-mail: lavinia.heisenberg@eth-its.ethz.ch

    2016-03-01

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

  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. Massive Star Burps, Then Explodes

    NASA Astrophysics Data System (ADS)

    2007-04-01

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

  9. 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.

  10. Remark on massive particle's de Sitter tunneling

    SciTech Connect

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

    2013-11-01

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

  11. Causality in 3D massive gravity theories

    NASA Astrophysics Data System (ADS)

    Edelstein, José D.; Giribet, Gaston; Gómez, Carolina; Kilicarslan, Ercan; Leoni, Matías; Tekin, Bayram

    2017-05-01

    We study the constraints coming from the local causality requirement in various 2 +1 dimensional dynamical theories of gravity. In topologically massive gravity, with a single parity noninvariant massive degree of freedom, and in new massive gravity, with two massive spin-2 degrees of freedom, causality and unitarity are compatible with each other and both require the Newton's constant to be negative. In their extensions, such as the Born-Infeld gravity and the minimal massive gravity the situation is similar and quite different from their higher dimensional counterparts, such as quadratic (e.g., Einstein-Gauss-Bonnet) or cubic theories, where causality and unitarity are in conflict. We study the problem both in asymptotically flat and asymptotically anti-de Sitter spaces.

  12. 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…

  13. Clustering Patterns of Engagement in Massive Open Online Courses (MOOCs): The Use of Learning Analytics to Reveal Student Categories

    ERIC Educational Resources Information Center

    Khalil, Mohammad; Ebner, Martin

    2017-01-01

    Massive Open Online Courses (MOOCs) are remote courses that excel in their students' heterogeneity and quantity. Due to the peculiarity of being massiveness, the large datasets generated by MOOC platforms require advanced tools and techniques to reveal hidden patterns for purposes of enhancing learning and educational behaviors. This publication…

  14. 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

  15. Unusual cause of massive hemothorax: spontaneous rupture of nonfunctioning mediastinal paraganglioma

    PubMed Central

    Lin, Feng; Liu, Chengwu; Ma, Lin; Pu, Qiang; Zhu, Yunke; Xiao, Zhilan; Guo, Chenglin; Zhang, Xiaolong; Li, Chuan

    2016-01-01

    Mediastinal paraganglioma is a rare neurogenic tumor with a hypervascular feature. The spontaneous rupture of mediastinal paraganglioma is an unusual cause of massive hemothorax. Here we present a case of 39-year-old man with massive hemothorax due to the spontaneous rupture of a mediastinal paraganglioma. The man underwent successful resection of tumor and had an uneventful recovery. To our knowledge, this is the first reported case of spontaneous rupture of nonfunctioning mediastinal paraganglioma. PMID:28149584

  16. A massively asynchronous, parallel brain

    PubMed Central

    Zeki, Semir

    2015-01-01

    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

  17. Magnetic Fields in Massive Filaments

    NASA Astrophysics Data System (ADS)

    Pillai, Thushara

    Magnetic fields pervade galaxies, shaping them from the largest scales to the smallest star forming scales. A firm understanding of their role is crucial to our understanding of the physics of ISM. A dominant phase of the ISM that has received considerable attention is that of filaments which are ubiquitous and dominate the mass reservoir in molecular clouds. Enormous progress has been made recently towards understanding filament properties. The next major step should be to understand the role of magnetic fields in filaments. We propose to take advantage of HAWC+ dust emission polarimeter now available on SOFIA to launch a pilot polarization study towards three major classes of filaments: (i) Pristine (ii) Hub-Filament systems and (iii) Perturbed. HAWC+ will trace the connection between the star forming cores and the filaments enveloping them. By covering a vast range in parameter space from quiescent to active filaments, we will be constraining the initial conditions prior to star formation, during star formation and after star formation (feedback from newly formed stars on their parent clouds.) The interpretation of observations will be supported by extensive custom-made numerical simulations of magnetized clouds and subsequent dust radiative transfer with various grain alignment mechanisms, as provided by collaborators. Combined, these observations will provide the first panoramic view of the magnetized nature of massive filaments in the ISM.

  18. Magnetic Fields in Massive Filaments

    NASA Astrophysics Data System (ADS)

    Pillai, G. S. Thushara

    2015-10-01

    Magnetic fields pervade galaxies, shaping them from the largest scales to the smallest star forming scales. A firm understanding of their role is crucial to our understanding of the physics of ISM. A dominant phase of the ISM that has received considerable attention is that of filaments which are ubiquitous and dominate the mass reservoir in molecular clouds. Enormous progress has been made recently towards understanding filament properties. The next major step should be to understand the role of magnetic fields in filaments. We propose to take advantage of HAWC+ dust emission polarimeter now available on SOFIA to launch a pilot polarization study towards three major classes of filaments: (i) Pristine (ii) Hub-Filament systems and (iii) Perturbed. HAWC+ will trace the connection between the star forming cores and the filaments enveloping them. By covering a vast range in parameter space from quiescent to active filaments, we will be constraining the initial conditions prior to star formation, during star formation and after star formation (feedback from newly formed stars on their parent clouds.) The interpretation of observations will be supported by extensive custom--made numerical simulations of magnetized clouds and subsequent dust radiative transfer with various grain alignment mechanisms, as provided by collaborators. Combined, these observations will provide the first panoramic view of the magnetized nature of massive filaments in the ISM.

  19. Massive chondroma of pelvis - case report.

    PubMed

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

    2009-01-01

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

  20. Rotation in young massive star clusters

    NASA Astrophysics Data System (ADS)

    Mapelli, Michela

    2017-05-01

    Hydrodynamical simulations of turbulent molecular clouds show that star clusters form from the hierarchical merger of several sub-clumps. We run smoothed-particle hydrodynamics simulations of turbulence-supported molecular clouds with mass ranging from 1700 to 43 000 M⊙. We study the kinematic evolution of the main cluster that forms in each cloud. We find that the parent gas acquires significant rotation, because of large-scale torques during the process of hierarchical assembly. The stellar component of the embedded star cluster inherits the rotation signature from the parent gas. Only star clusters with final mass < few × 100 M⊙ do not show any clear indication of rotation. Our simulated star clusters have high ellipticity (˜0.4-0.5 at t = 4 Myr) and are subvirial (Qvir ≲ 0.4). The signature of rotation is stronger than radial motions due to subvirial collapse. Our results suggest that rotation is common in embedded massive (≳1000 M⊙) star clusters. This might provide a key observational test for the hierarchical assembly scenario.

  1. Mining knowledge in astrophysical massive data sets

    NASA Astrophysics Data System (ADS)

    Brescia, Massimo; Longo, Giuseppe; Pasian, Fabio

    2010-11-01

    Modern scientific data mainly consist of huge data sets gathered by a very large number of techniques and stored in much diversified and often incompatible data repositories. More in general, in the e-science environment, it is considered as a critical and urgent requirement to integrate services across distributed, heterogeneous, dynamic “virtual organizations” formed by different resources within a single enterprise. In the last decade, Astronomy has become an immensely data-rich field due to the evolution of detectors (plates to digital to mosaics), telescopes and space instruments. The Virtual Observatory approach consists of the federation under common standards of all astronomical archives available worldwide, as well as data analysis, data mining and data exploration applications. The main drive behind such an effort is that once the infrastructure is complete, it will allow a new type of multi-wavelength, multi-epoch science, which can only be barely imagined. Data mining, or knowledge discovery in databases, while being the main methodology to extract the scientific information contained in such Massive Data Sets (MDS), poses crucial problems since it has to orchestrate complex problems posed by transparent access to different computing environments, scalability of algorithms, reusability of resources, etc. In the present paper we summarize the present status of the MDS in the Virtual Observatory and what is currently done and planned to bring advanced data mining methodologies in the case of the DAME (DAta Mining and Exploration) project.

  2. 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.

  3. Massive Hemolysis Causing Renal Failure in Acute Hepatitis E Infection

    PubMed Central

    Karki, Pragya; Malik, Sarthak; Mallick, Bipadabhanjan; Sharma, Vishal; Rana, Surinder S

    2016-01-01

    Abstract Acute viral hepatitis is usually a self-limiting illness. However, it can lead to complications that can be life-threatening, such as acute liver failure. Glucose 6 phosphate dehydrogenase (G6PD) deficiency in the setting of acute viral hepatitis can lead to a massive hemolysis, manifesting as acute kidney injury and markedly raised bilirubin levels; although cases are rare. Here, we report such a case. The patient had a viral hepatitis E infection and presented with kidney injury requiring dialysis. Examination showed very high mixed hyperbilirubinemia due to massive intravascular hemolysis. The patient experienced a long, protracted course of illness, requiring renal replacement therapy with other supportive management, which led to improvement over a period of four weeks. This case highlights the importance of recognizing associated hemolysis in a patient with viral hepatitis who presents with very high bilirubin levels or associated kidney injury. Such patients will require aggressive supportive care with prompt fluid and electrolyte management. PMID:28097104

  4. The impact of temperature loading on massive concrete block resistance

    NASA Astrophysics Data System (ADS)

    Beran, Pavel; Kočí, Jan

    2017-07-01

    Very large and massive concrete blocks with thickness in interval 3.5 - 6 meters are often designed in cement industry. These massive blocks have high heat inertial and thus the thermal stress due to nonlinear temperature gradient in concrete block may occur. The coupled thermo-mechanical analysis of concrete block in Prague Czech Republic and Sterlitamak Russia was made. By the numerical model of concrete block was analyzed the typical year (called reference year) in particular localities. The results show that in concrete block the thermal stresses which are higher than the tensile strength of concrete originate. Therefore, the concrete block should be reinforced by steel rods. The values of stresses are markedly affected by climate. The significantly higher values of thermal stresses were detected in Sterlitamak than in Prague.

  5. Nonsingular universe in massive gravity's rainbow

    NASA Astrophysics Data System (ADS)

    Hendi, S. H.; Momennia, M.; Eslam Panah, B.; Panahiyan, S.

    2017-06-01

    One of the fundamental open questions in cosmology is whether we can regard the universe evolution without singularity like a Big Bang or a Big Rip. This challenging subject stimulates one to regard a nonsingular universe in the far past with an arbitrarily large vacuum energy. Considering the high energy regime in the cosmic history, it is believed that Einstein gravity should be corrected to an effective energy dependent theory which could be acquired by gravity's rainbow. On the other hand, employing massive gravity provided us with solutions to some of the long standing fundamental problems of cosmology such as cosmological constant problem and self acceleration of the universe. Considering these aspects of gravity's rainbow and massive gravity, in this paper, we initiate studying FRW cosmology in the massive gravity's rainbow formalism. At first, we show that although massive gravity modifies the FRW cosmology, but it does not itself remove the big bang singularity. Then, we generalize the massive gravity to the case of energy dependent spacetime and find that massive gravity's rainbow can remove the early universe singularity. We bring together all the essential conditions for having a nonsingular universe and the effects of both gravity's rainbow and massive gravity generalizations on such criteria are determined.

  6. 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

  7. Nucleosynthesis in Massive Stars and Supernovae

    NASA Astrophysics Data System (ADS)

    Woosley, S. E.; Hoffman, R. D.; Timmes, F. X.; Weaver, T. A.; Thielemann, F.-K.

    1997-02-01

    We briefly summarize some recent work on nucleosynthesis in massive stars and supernovae. Here we explore: 1) the effect of including additional sources of nucleosynthesis besides massive stars into the mixture - especially classical novae and several varieties of Type Ia supernovae; 2) the sensitivity of the results to choices of theoretical nuclear reaction rates in the mass range 28 <= A <= 70; 3) nucleosynthesis above the iron group using a much larger reaction network; and 4) the sensitivity of these results to recent revisions in experimental reaction rates for isotopes A <= 28. For the recently revised rates, 17O is no longer a massive star product.

  8. Inside-out formation of massive galaxies

    NASA Astrophysics Data System (ADS)

    de la Rosa, I. G.

    2017-03-01

    A significant fraction of the present day massive galaxies have compact cores embedded inside their disks or halos. Strikingly, those compact cores are similar to the massive high-redshift quiescent compact galaxies, nicknamed red-nuggets. We present observational evidence supporting an inside-out formation scenario, where present-day massive galaxies can begin as dense spheroidal cores (red-nuggets), around which either a spheroidal halo or a disk are accreted later. This contribution is based on the paper by de la Rosa et al. (2016).

  9. Fluid/gravity correspondence for massive gravity

    NASA Astrophysics Data System (ADS)

    Pan, Wen-Jian; Huang, Yong-Chang

    2016-11-01

    In this paper, we investigate the fluid/gravity correspondence in the framework of massive Einstein gravity. Treating the gravitational mass terms as an effective energy-momentum tensor and utilizing the Petrov-like boundary condition on a timelike hypersurface, we find that the perturbation effects of massive gravity in bulk can be completely governed by the incompressible Navier-Stokes equation living on the cutoff surface under the near horizon and nonrelativistic limits. Furthermore, we have concisely computed the ratio of dynamical viscosity to entropy density for two massive Einstein gravity theories, and found that they still saturate the Kovtun-Son-Starinets (KSS) bound.

  10. 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

  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. 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.

  13. Evolution of Massive Stars at Low Metallicity

    NASA Astrophysics Data System (ADS)

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

    2008-06-01

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

  14. 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.

  15. 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.

  16. Some interesting features of new massive gravity

    NASA Astrophysics Data System (ADS)

    Accioly, Antonio; Helayël-Neto, José; Scatena, Eslley; Morais, Jefferson; Turcati, Rodrigo; Pereira-Dias, Bruno

    2011-11-01

    A sketch of a proof that new massive gravity—the massive 3D gravity model proposed by Bergshoeff, Hohm and Townsend (BHT)—is the only unitary system at the tree level that can be constructed by augmenting 3D general relativity through (curvature)2-terms is presented. Two interesting gravitational properties of the BHT model, namely, time dilation and time delay, which have no counterpart in the usual Einstein 3D gravity, are analyzed as well.

  17. 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

  18. Massive vulvar edema in a woman with preeclampsia: a case report.

    PubMed

    Daponte, Alexandros; Skentou, Hara; Dimopoulos, Konstantinos D; Kallitsaris, Athanasios; Messinis, Ioannis E

    2007-11-01

    Massive vulvar edema in a woman with preeclampsia preceded the development of massive ascites and impending eclampsia. A 17-year-old preeclamptic, primiparous woman was admitted with preeclampsia and massive vulvar edema. Other causes were excluded. The vulvar edema increased as the blood pressure and ascites increased, and a severe headache developed. Cesarean section for increasing preclampsia was performed. In the puerperium, the blood pressure improved and vulvar edema resolved. The clinical picture of the vulvar edema correlated with the severity of the preeclampsia. The presence of vulvar edema in women with preeclampsia should indicate immediate admission to the hospital. These patients must be considered as at high risk, and close monitoring must be instituted. In our case, vulvar edema preceded massive ascites development. We assume a common development mechanism for these signs in preeclampsia, due mainly to increased capillary permeability and hypoalbuminemia. The attending physician must be prepared for immediate delivery and possible preeclampsia complications in these patients.

  19. Three-dimensional Casimir piston for massive scalar fields

    SciTech Connect

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

    2009-08-15

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

  20. 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.

  1. 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.

  2. 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

  3. The Hydrangea simulations: galaxy formation in and around massive clusters

    NASA Astrophysics Data System (ADS)

    Bahé, Yannick M.; Barnes, David J.; Dalla Vecchia, Claudio; Kay, Scott T.; White, Simon D. M.; McCarthy, Ian G.; Schaye, Joop; Bower, Richard G.; Crain, Robert A.; Theuns, Tom; Jenkins, Adrian; McGee, Sean L.; Schaller, Matthieu; Thomas, Peter A.; Trayford, James W.

    2017-10-01

    We introduce the Hydrangea simulations, a suite of 24 cosmological hydrodynamic zoom-in simulations of massive galaxy clusters (M200c = 1014-1015.4 M⊙) with baryon particle masses of ˜106 M⊙. Designed to study the impact of the cluster environment on galaxy formation, they are a key part of the `Cluster-EAGLE' project. They use a galaxy formation model developed for the EAGLE project, which has been shown to yield both realistic field galaxies and hot gas fractions of galaxy groups consistent with observations. The total stellar mass content of the simulated clusters agrees with observations, but central cluster galaxies are too massive, by up to 0.6 dex. Passive satellite fractions are higher than in the field, and at stellar masses Mstar > 1010 M⊙, this environmental effect is quantitatively consistent with observations. The predicted satellite stellar mass function matches data from local cluster surveys. Normalized to total mass, there are fewer low-mass (Mstar ≲ 1010 M⊙) galaxies within the virial radius of clusters than in the field, primarily due to star formation quenching. Conversely, the simulations predict an overabundance of massive galaxies in clusters compared to the field that persists to their far outskirts (>5 r200c). This is caused by a significantly increased stellar mass fraction of (sub-)haloes in the cluster environment, by up to ˜0.3 dex even well beyond r200c. Haloes near clusters are also more concentrated than equally massive field haloes, but these two effects are largely uncorrelated.

  4. Prediction of massive bleeding. Shock index and modified shock index.

    PubMed

    Terceros-Almanza, L J; García-Fuentes, C; Bermejo-Aznárez, S; Prieto-Del Portillo, I J; Mudarra-Reche, C; Sáez-de la Fuente, I; Chico-Fernández, M

    2017-04-08

    To determine the predictive value of the Shock Index and Modified Shock Index in patients with massive bleeding due to severe trauma. Retrospective cohort. Severe trauma patient's initial attention at the intensive care unit of a tertiary hospital. Patients older than 14 years that were admitted to the hospital with severe trauma (Injury Severity Score >15) form January 2014 to December 2015. We studied the sensitivity (Se), specificity (Sp), positive and negative predictive value (PV+ and PV-), positive and negative likelihood ratio (LR+ and LR-), ROC curves (Receiver Operating Characteristics) and the area under the same (AUROC) for prediction of massive hemorrhage. 287 patients were included, 76.31% (219) were male, mean age was 43,36 (±17.71) years and ISS was 26 (interquartile range [IQR]: 21-34). The overall frequency of massive bleeding was 8.71% (25). For Shock Index: AUROC was 0.89 (95% confidence intervals [CI] 0.84 to 0.94), with an optimal cutoff at 1.11, Se was 91.3% (95% CI: 73.2 to 97.58) and Sp was 79.69% (95% CI: 74.34 to 84.16). For the Modified Shock Index: AUROC was 0.90 (95% CI: 0.86 to 0.95), with an optimal cutoff at 1.46, Se was 95.65% (95% CI: 79.01 to 99.23) and Sp was 75.78% (95% CI: 70.18 to 80.62). Shock Index and Modified Shock Index are good predictors of massive bleeding and could be easily incorporated to the initial workup of patients with severe trauma. Copyright © 2017 Elsevier España, S.L.U. y SEMICYUC. All rights reserved.

  5. 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.

  6. 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

  7. 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.

  8. Impact of massive neutrinos on the nonlinear matter power spectrum.

    PubMed

    Saito, Shun; Takada, Masahiro; Taruya, Atsushi

    2008-05-16

    We present the first attempt to analytically study the nonlinear matter power spectrum for a mixed dark matter model containing neutrinos of total mass ~0.1 eV, based on cosmological perturbation theory. The suppression in the power spectrum amplitudes due to massive neutrinos is enhanced in the weakly nonlinear regime. We demonstrate that, thanks to this enhanced effect, the use of such a nonlinear model may enable a precision of sigma(m(nu,tot)) ~ 0.07 eV in constraining the total neutrino mass for the planned galaxy redshift survey, a factor of 2 improvement compared to the linear regime.

  9. Possible detection of super massive very slow GUTS monopole.

    NASA Astrophysics Data System (ADS)

    Khalil, A. E.

    A conceptual design idea for a detector of super massive very slow grand unified theories (GUTS) monopoles is discussed. The idea is based on the total stopping power due to the field energy generated by the supercurrents when a slowly moving monopole β ≍ 10-4 passes through a superconductor. The detector incorporates a superconducting Al disc with dimensions chosen for maximum phonon thermalization energy, surrounded by an array of plastic scintillators to provide a monopole trigger and cosmic ray veto. The integrated system acts as a velocity filter for very slow Dirac galactic monopoles.

  10. Massive gas gangrene secondary to occult colon carcinoma.

    PubMed

    Griffin, Andrew S; Crawford, Matthew D; Gupta, Rajan T

    2016-06-01

    Gas gangrene is a rare but often fatal soft-tissue infection. Because it is uncommon and the classic symptom of crepitus does not appear until the infection is advanced, prompt diagnosis requires a high index of suspicion. We present a case report of a middle-aged man who presented with acute onset lower-extremity pain that was initially thought to be due to deep vein thrombosis. After undergoing workup for pulmonary embolism, he was found to have massive gas gangrene of the lower extremity secondary to an occult colon adenocarcinoma and died within hours of presentation from multisystem organ failure.

  11. Massive psoas haematoma causing lumbar plexus palsy: a case report.

    PubMed

    Conesa, Xavier; Ares, Oscar; Seijas, Roberto

    2012-04-01

    An 84-year-old man who was receiving oral anticoagulation therapy presented with complete lumbar plexus palsy caused by a massive psoas haematoma. Conservative treatment rather than drainage of the haematoma was undertaken, because of the risk of bleeding complications and mortality. At the one-year follow-up, the patient had no clinical signs of neurological recovery. The patient died 2 months later due to his concurrent medical problems. A high degree of suspicion is needed for the diagnosis because of the insidiously developing neurological deficit.

  12. How can young massive clusters reach their present-day sizes?

    NASA Astrophysics Data System (ADS)

    Banerjee, Sambaran; Kroupa, Pavel

    2017-01-01

    Context. The classic question of how young massive star clusters attain the shapes and sizes, as we find them today, is still a difficult one. Both observational and computational studies of star-forming massive molecular gas clouds suggest that massive cluster formation is primarily triggered along the small-scale (≲0.3 pc) filamentary substructures within the clouds. Aims: The present study investigates the possible ways in which a filament-like, compact, massive star cluster (effective radius 0.1-0.3 pc) can expand more than 10 times, still remaining massive enough (≳ 104M⊙) to become the young massive star cluster that we observe today. Methods: To this end, model massive clusters (initially 104-105M⊙) are evolved using Sverre Aarseth's state-of-the-art N-body code NBODY7. Apart from the accurate calculation of two-body relaxation of the constituent stars, these evolutionary models take into account stellar-evolutionary mass loss and dynamical energy injection due to massive, tight primordial binaries and stellar-remnant black holes and neutron stars. These calculations also include a solar-neighbourhood-like external tidal field. All the computed clusters expand with time, and their sizes (effective radii) are compared with those observed for young massive clusters (≲ 100 Myr) in the Milky Way and other nearby galaxies. Results: In this study, it is found that beginning from the above compact sizes, a star cluster cannot expand on its own, i.e., due to two-body relaxation, stellar mass loss, and dynamical heating by primordial binaries and compact stars up to the observed sizes of young massive clusters; star clusters always remain much more compact than the observed ones. Conclusions: This calls for additional mechanisms that boost the expansion of a massive cluster after its assembly. Using further N-body calculations, it is shown that a substantial residual gas expulsion with ≈ 30% star formation efficiency can indeed swell the newborn embedded

  13. A Hunt for Massive Starless Cores

    NASA Astrophysics Data System (ADS)

    Kong, Shuo; Tan, Jonathan C.; Caselli, Paola; Fontani, Francesco; Liu, Mengyao; Butler, Michael J.

    2017-01-01

    We carry out an ALMA {{{N}}}2{{{D}}}+(3-2) and 1.3 mm continuum survey of 32 high-mass surface density regions of seven infrared dark clouds, with the aim of finding massive starless cores that may form the initial conditions for the formation of massive stars. Cores showing strong {{{N}}}2{{{D}}}+(3-2) emission are expected to be highly deuterated and indicative of early, potentially pre-stellar stages of star formation. We also present maps of these regions in ancillary line tracers, including C18O(2-1), DCN(3-2), and DCO+(3-2). Over 100 {{{N}}}2{{{D}}}+ cores are identified with our newly developed core-finding algorithm, based on connected structures in position–velocity space. The most massive core has ∼ 70 {M}ȯ (potentially ∼ 170 {M}ȯ ) and so may be representative of the initial conditions or early stages of massive star formation. The existence and dynamical properties of such cores constrain massive star formation theories. We measure the line widths and thus velocity dispersion of six of the cores with strongest {{{N}}}2{{{D}}}+(3-2) line emission, finding results that are generally consistent with virial equilibrium of pressure confined cores.

  14. Radial Infall onto a Massive Molecular Filament

    NASA Astrophysics Data System (ADS)

    Battersby, Cara

    2015-08-01

    The newly discovered massive molecular filament G32.02+0.05 (~70 pc long, 10^5 Msun) has been shaped and compressed by older generations of massive stars. The similarity of this filament in physical structure (density profile, temperature) to much smaller star-forming filaments, suggests that the mechanism to form such filaments is a universal process. The densest portion of the filament, apparent as an Infrared Dark Cloud (IRDC) appears to have been compressed on both sides by a pair of bubbles and now shows a range of massive star formation signatures throughout. We investigate the kinematics in this massive star-forming filament and find velocity coherence along the filament and global blue asymmetric line profiles. These line asymmetries are interpreted as a signature of large-scale radial collapse. Using line asymmetries observed with optically thick HCO+ (1-0) and optically thin H13CO+ (1-0) across a range of massive star forming regions in the filament, we estimate the global radial infall rate of the filament to range from a few 100 to a few 1000 Msun/Myr/pc^2. At its current infall rate the densest portions of the cloud will more than double their current mass within a Myr. The discovery of such a reservoir of infalling gas has important ramifications on the course of star formation in the cloud and on our overall understanding of star cluster formation.

  15. 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.

  16. Very massive binaries in R 136

    NASA Astrophysics Data System (ADS)

    Chené, André-Nicolas; Schnurr, Olivier; Crowther, Paul A.; Fernández-Lajús, Eduardo; Moffat, Anthony F. J.

    2011-07-01

    As recent observations have shown, luminous, hydrogen-rich WN5-7h stars (and their somewhat less extreme cousins, O3f/WN6 stars) are the most massive main-sequence stars known. However, not nearly enough very massive stars have been reliably weighed to yield a clear picture of the upper initial-mass function (IMF). We therefore have carried out repeated high-quality spectroscopy of four new O3f/WN6 and WN5-7h binaries in R136 in the LMC with GMOS at Gemini-South, to derive Keplerian orbits for both components, respectively, and thus to directly determine their masses. We also monitored binary candidates and other, previously unsurveyed stars, to increase the number of very massive stars that can be directly weighed.

  17. 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.

  18. Gyromagnetic ratio of a massive body.

    NASA Technical Reports Server (NTRS)

    Cohen, J. M.; Tiomno, J.; Wald, R. M.

    1973-01-01

    It is well known that the gyromagnetic ratio (g factor) of a classical, slowly rotating body whose charge density is proportional to its mass density must be equal to unity. However, if the body is very massive, the spacetime curvature effects of general relativity become important and the result g = 1 is no longer valid. We calculate here the gyromagnetic ratio of a slowly rotating, massive shell with uniform charge density. When the shell is large compared with the Schwarzschild radius we have g = 1, but as the shell becomes more massive the g factor increases. In the limit as the shell approaches its Schwarzschild radius we obtain g approaching 2 (the same value as for an electron).

  19. HST Infrared Imaging of MASSIVE Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Jensen, Joseph B.; Goullaud, Charles; Blakeslee, John; Mitchiner, Casey; Ma, Chung-Pei; Greene, Jenny E.; McConnell, Nicholas J.; Thomas, Jens

    2017-01-01

    We have recently obtained high-resolution HST WFC3/IR F110W (J-band) images of 34 early-type galaxies in the MASSIVE study sample. These galaxies are among the most massive in the local universe, and were chosen to study the connection between supermassive central black holes and their host galaxies. To determine accurate masses for the black holes, we are measuring high-precision surface brightness fluctuation (SBF) distances to the galaxies. The WFC3/IR data also allow us to measure high spatial resolution central surface brightness profiles to understand better the nuclear structure and dynamics of the galaxies. We present a first look at the IR images, profiles, and SBF magnitudes for 34 galaxies in the MASSIVE sample.

  20. Pseudoangiomatous stromal hyperplasia causing massive breast enlargement.

    PubMed

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

    2015-10-16

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

  1. 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.

  2. The Circumgalactic Medium in Massive Halos

    NASA Astrophysics Data System (ADS)

    Chen, Hsiao-Wen

    This chapter presents a review of the current state of knowledge on the cool (T ˜ 104 K) halo gas content around massive galaxies at z ≈ 0. 2-2. Over the last decade, significant progress has been made in characterizing the cool circumgalactic gas in massive halos of M h ≈ 1012-14 M⊙ at intermediate redshifts using absorption spectroscopy. Systematic studies of halo gas around massive galaxies beyond the nearby universe are made possible by large spectroscopic samples of galaxies and quasars in public archives. In addition to accurate and precise constraints for the incidence of cool gas in massive halos, detailed characterizations of gas kinematics and chemical compositions around massive quiescent galaxies at z ≈ 0. 5 have also been obtained. Combining all available measurements shows that infalling clouds from external sources are likely the primary source of cool gas detected at d 100 d\\gtrsim 100 kpc from massive quiescent galaxies. The origin of the gas closer in is currently less certain, but SNe Ia driven winds appear to contribute significantly to cool gas found at d < 100 kpc. In contrast, cool gas observed at d 200 d\\lesssim 200 kpc from luminous quasars appears to be intimately connected to quasar activities on parsec scales. The observed strong correlation between cool gas covering fraction in quasar host halos and quasar bolometric luminosity remains a puzzle. Combining absorption-line studies with spatially resolved emission measurements of both gas and galaxies is the necessary next step to address remaining questions.

  3. 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.

  4. 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.

  5. Factors associated with massive fibrosis in silicosis.

    PubMed Central

    Ng, T P; Chan, S L

    1991-01-01

    Data on 1432 patients with silicosis on a register in Hong Kong were analysed to examine the association of massive fibrosis with possible predisposing factors. Detailed occupational and clinical histories, clinical records, radiographic readings according to the International Standard Classification of Radiographs of Pneumoconioses, and environmental dust measurements from hygiene surveys were used to obtain information for several variables--namely, age at first exposure, relative dust exposure level, duration of exposure, smoking, previous recorded history of tuberculosis, and background profusion of small opacities. The most significant risk factors associated with massive fibrosis were high relative dust exposure level, a history of tuberculosis, and increased background profusion of small opacities. PMID:2038729

  6. 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.

  7. Massive intracerebral hemorrhage associated with Wegener granulomatosis.

    PubMed

    Ceri, Mevlut; Ortabozkoyun, Levent; Unverdi, Selman; Kirac, Mustafa; Duranay, Murat

    2012-06-01

    Wegener granulomatosis (WG) is a necrotizing granulomatous vasculitis that predominantly affects airways and kidneys. But central nervous system involvement (7-11%) is an uncommon. Massive ICH may occur in the course of WG, and this serious condition is related with high risk of mortality. Therefore, the new treatment strategies may be considered in addition to classical practices in serious organ involvement and recurrent attack. Here, we present an adult patient with WG whose disease was complicated by a massive intracerebral hemorrhage (ICH), which subsequently led to death.

  8. 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.

  9. Prediction of Massive Transfusion in Trauma.

    PubMed

    Cantle, Paul M; Cotton, Bryan A

    2017-01-01

    Hemorrhage is the leading cause of preventable death in trauma. Damage control resuscitation relies on permissive hypotension, minimizing crystalloid use, and early implementation of massive transfusion protocols with established blood component ratios. These protocols improve the survival of the severely injured patient. Trauma physicians must quickly and accurately predict when a massive transfusion protocol should be activated. Several validated transfusion scores have been developed for this purpose. Many of these scores are useful for resuscitation research. One option, the ABC score, is an accurate, validated, and clinically useful score that is simple to calculate and rapidly obtained. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. 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.

  11. Massive Hemorrhage From Multiple Hepatic Artery Aneurysms.

    PubMed

    Kahn, S Lowell; McClain, Jonathan; Kaufman, Jeffrey L

    2016-10-01

    A 66-year-old man, with an abnormal porta hepatis, consistent with tumor or inflammation, developed massive bleeding from one of numerous hepatic artery aneurysms, and coil embolization achieved control of bleeding. He died of subsequent multisystem organ failure, and the most likely diagnosis was either polyarteritis nodosa or segmental arterial mediolysis. Although the dual hepatic blood supply allows a degree of arterial embolization, this case demonstrates the risks associated with large territory hepatic arterial embolization in the presence of hemodynamic instability. We discuss the management issues related to massive hepatic bleeding when no surgical approach is possible.

  12. SALT Spectroscopy of Evolved Massive Stars

    NASA Astrophysics Data System (ADS)

    Kniazev, A. Y.; Gvaramadze, V. V.; Berdnikov, L. N.

    2017-06-01

    Long-slit spectroscopy with the Southern African Large Telescope (SALT) of central stars of mid-infrared nebulae detected with the Spitzer Space Telescope and Wide-Field Infrared Survey Explorer (WISE) led to the discovery of numerous candidate luminous blue variables (cLBVs) and other rare evolved massive stars. With the recent advent of the SALT fiber-fed high-resolution echelle spectrograph (HRS), a new perspective for the study of these interesting objects is appeared. Using the HRS we obtained spectra of a dozen newly identified massive stars. Some results on the recently identified cLBV Hen 3-729 are presented.

  13. Growth histories in bimetric massive gravity

    SciTech Connect

    Berg, Marcus; Buchberger, Igor; Enander, Jonas; Mörtsell, Edvard; Sjörs, Stefan E-mail: igor.buchberger@kau.se E-mail: edvard@fysik.su.se

    2012-12-01

    We perform cosmological perturbation theory in Hassan-Rosen bimetric gravity for general homogeneous and isotropic backgrounds. In the de Sitter approximation, we obtain decoupled sets of massless and massive scalar gravitational fluctuations. Matter perturbations then evolve like in Einstein gravity. We perturb the future de Sitter regime by the ratio of matter to dark energy, producing quasi-de Sitter space. In this more general setting the massive and massless fluctuations mix. We argue that in the quasi-de Sitter regime, the growth of structure in bimetric gravity differs from that of Einstein gravity.

  14. 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

  15. Radial Infall onto a Massive Molecular Filament

    NASA Astrophysics Data System (ADS)

    Battersby, Cara; Myers, Philip C.; Shirley, Yancy L.; Keto, Eric; Kirk, Helen

    The newly discovered Massive Molecular Filament (MMF) G32.02+0.05 (~ 70 pc long, 105 M⊙) has been shaped and compressed by older generations of massive stars. The similarity of this filament in physical structure (density profile, temperature) to much smaller star-forming filaments, suggests that the mechanism to form such filaments may be a universal process. The densest portion of the filament, apparent as an Infrared Dark Cloud (IRDC) shows a range of massive star formation signatures throughout. We investigate the kinematics in this filament and find widespread inverse P cygni asymmetric line profiles. These line asymmetries are interpreted as a signature of large-scale radial collapse. Using line asymmetries observed with optically thick HCO+ (1-0) and optically thin H13CO+ (1-0) across a range of massive star forming regions in the filament, we estimate the global radial infall rate of the filament to range from a few 100 to a few 1000 M⊙ Myr-1 pc-1. At its current infall rate the densest portions of the cloud will more than double their current mass within a Myr.

  16. 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…

  17. Evolutionary tracks of massive stars during formation

    NASA Astrophysics Data System (ADS)

    Smith, Michael D.

    2014-02-01

    A model for massive stars is constructed by piecing together evolutionary algorithms for the protostellar structure, the environment, the inflow and the radiation feedback. We investigate specified accretion histories of constant, decelerating and accelerating forms and consider both hot and cold accretion, identified with spherical free-fall and disc accretion, respectively. Diagnostic tools for the interpretation of the phases of massive star formation and testing the evolutionary models are then developed. Evolutionary tracks able to fit Herschel Space Telescope data require the generated stars to be three to four times less massive than in previous interpretations, thus being consistent with clump star formation efficiencies of 10-15 per cent. However, for these cold Herschel clumps, the bolometric temperature is not a good diagnostic to differentiate between accretion models. We also find that neither spherical nor disc accretion can explain the high radio luminosities of many protostars. Nevertheless, we discover a solution in which the extreme ultraviolet flux needed to explain the radio emission is produced if the accretion flow is via free-fall on to hotspots covering less than 10 per cent of the surface area. Moreover, the protostar must be compact, and so has formed through cold accretion. We show that these conclusions are independent of the imposed accretion history. This suggests that massive stars form via gas accretion through discs which, in the phase before the star bloats, download their mass via magnetic flux tubes on to the protostar.

  18. 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.

  19. BPS black hole horizons from massive IIA

    NASA Astrophysics Data System (ADS)

    Guarino, Adolfo

    2017-08-01

    The maximal four-dimensional supergravity with a dyonic ISO(7) gauging that arises from the reduction of massive IIA on a six-sphere has recently been shown to accommodate static BPS black holes with hyperbolic horizons. When restricted to the N=2 subsector that retains one vector multiplet and the universal hypermultiplet, the attractor mechanism was shown to fix both the vector charges and the scalar fields at the horizon to a unique configuration in terms of the gauging parameters. In order to assess the (non-)uniqueness of BPS black hole horizons from massive IIA, we extend the study of the attractor mechanism to other N=2 subsectors including additional matter multiplets. We note that, while extending the hypermultiplet sector does not modify the set of solutions to the attractor equations, the inclusion of additional vector multiplets results in new hyperbolic/spherical horizon configurations containing free parameters. The model with three vector multiplets and the universal hypermultiplet, which is the massive IIA analogue of the STU-model from M-theory, may play a relevant role in massive IIA holography.

  20. 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…

  1. The Fate of Massive Closed Strings

    SciTech Connect

    Chen Bin; Li Miao; She Jianhuang

    2005-12-02

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

  2. Nonlinear dynamics of 3D massive gravity

    NASA Astrophysics Data System (ADS)

    de Rham, Claudia; Gabadadze, Gregory; Pirtskhalava, David; Tolley, Andrew J.; Yavin, Itay

    2011-06-01

    We explore the nonlinear classical dynamics of the three-dimensional theory of "New Massive Gravity" proposed by Bergshoeff, Hohm and Townsend. We find that the theory passes remarkably highly nontrivial consistency checks at the nonlinear level. In particular, we show that: (1) In the decoupling limit of the theory, the interactions of the helicity-0 mode are described by a single cubic term — the so-called cubic Galileon — previously found in the context of the DGP model and in certain 4D massive gravities. (2) The conformal mode of the metric coincides with the helicity-0 mode in the decoupling limit. Away from this limit the nonlinear dynamics of the former is described by a certain generalization of Galileon interactions, which like the Galileons themselves have a well-posed Cauchy problem. (3) We give a non-perturbative argument based on the presence of additional symmetries that the full theory does not lead to any extra degrees of freedom, suggesting that a 3D analog of the 4D Boulware-Deser ghost is not present in this theory. Last but not least, we generalize "New Massive Gravity" and construct a class of 3D cubic order massive models that retain the above properties.

  3. Massive Young Star and its Cradle

    NASA Image and Video Library

    2010-07-14

    This star-forming region, captured by NASA Spitzer Space Telescope, is dominated by the bright, young star IRAS 13481-6124; it is the first massive baby star for which astronomers could obtain a detailed look at the dusty disk closely encircling it.

  4. 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.

  5. 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. © 2014 The Authors. Transfusion Medicine © 2014 British Blood Transfusion Society.

  6. NOTE: Circular symmetry in topologically massive gravity

    NASA Astrophysics Data System (ADS)

    Deser, S.; Franklin, J.

    2010-05-01

    We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null.

  7. 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…

  8. The Dynamics of Massive Starless Cores

    NASA Astrophysics Data System (ADS)

    Tan, Jonathan; Caselli, P.; Fontani, F.; Kong, S.; Butler, M. J.

    2012-05-01

    Progress towards resolving a decade-long debate about how massive stars form can be made by determining if massive starless cores exist in a state of near virial equilibrium. These are the initial conditions invoked by the Core Accretion model of McKee & Tan (2003). Alternatively, the Competitive Accretion model of Bonnell et al. (2001) requires sub-virial conditions. We have identified 4 prime examples of massive ( 50 Msun) cores from mid-infrared (MIR) extinction mapping (Butler & Tan 2009, 2012) of Infrared Dark Clouds. We have found spectacularly high deuterated fractions of N_2H+ of 0.5 in these objects with the IRAM 30m telescope (Fontani et al. 2011). Thus N_2D+ is expected to be an excellent tracer of the kinematics of these cold, dark cores, where most other molecular tracers are thought to be depleted from the gas phase. We report on ALMA Cycle 0 Compact Configuration Band 6 observations of these 4 cores that probe the N_2D+(3-2) line on scales from 9" down to 2.3", well-matched to the structures we see in MIR extinction and discuss their implications for massive star formation theories.

  9. Organising pneumonia presenting as acute life threatening pulmonary haemorrhage.

    PubMed

    Narasimhaiah, Damodhara Honnavally; Chakravorty, Indranil; Swamy, Rajiv; Prakash, Doraiswamy

    2011-11-08

    Organising pneumonia, previously called bronchiolitis obliterans organising pneumonia is a clinicopathological entity of unknown aetiology, which has been reported with increasing frequency. Various modes of presentation have been described such as cough, fever, weight loss and alveolar opacities on chest radiograph. Haemoptysis as primary presenting symptom has only rarely been reported. The authors report a case in which massive life-threatening haemoptysis was the major presenting symptom. No aetiology was identified for the haemoptysis and the diagnosis was confirmed on postmortem histology. This case highlights the importance of considering organising pneumonia in the differential diagnosis of acute severe haemoptysis.

  10. Organising pneumonia presenting as acute life threatening pulmonary haemorrhage

    PubMed Central

    Narasimhaiah, Damodhara Honnavally; Chakravorty, Indranil; Swamy, Rajiv; Prakash, Doraiswamy

    2011-01-01

    Organising pneumonia, previously called bronchiolitis obliterans organising pneumonia is a clinicopathological entity of unknown aetiology, which has been reported with increasing frequency. Various modes of presentation have been described such as cough, fever, weight loss and alveolar opacities on chest radiograph. Haemoptysis as primary presenting symptom has only rarely been reported. The authors report a case in which massive life-threatening haemoptysis was the major presenting symptom. No aetiology was identified for the haemoptysis and the diagnosis was confirmed on postmortem histology. This case highlights the importance of considering organising pneumonia in the differential diagnosis of acute severe haemoptysis. PMID:22674096

  11. Modeling populations of rotationally mixed massive stars

    NASA Astrophysics Data System (ADS)

    Brott, I.

    2011-02-01

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

  12. Hypernuclei and massive neutron stars

    NASA Astrophysics Data System (ADS)

    Fortin, M.; Avancini, S. S.; Providência, C.; Vidaña, I.

    2017-06-01

    Background: The recent accurate measurement of the mass of two pulsars close to or above 2 M⊙ has raised the question of whether such large pulsar masses allow for the existence of exotic degrees of freedom, such as hyperons, inside neutron stars. Purpose: In the present work, we will investigate, within a phenomenological relativistic mean field approach, how the existing hypernuclei properties may constrain the neutron star equation of state and confront the neutron star maximum masses obtained with equations of state calibrated to hypernuclei properties with the astrophysical 2 M⊙ constraint. Method: The study is performed using a relativistic mean field approach to describe both the hypernuclei and the neutron star equations of state. Unified equations of state are obtained. A set of five models that describe 2 M⊙ when only nucleonic degrees of freedom are employed. Some of these models also satisfy other well-established laboratory or theoretical constraints. Results: The Λ -meson couplings are determined for all the models considered, and the Λ potential in symmetric nuclear matter and Λ matter at saturation are calculated. Maximum neutron star masses are determined for two values of the Λ -ω meson coupling, gω Λ=2 gω N/3 and gω Λ=gω N , and a wide range of values for gϕ Λ. Hyperonic stars with the complete baryonic octet are studied, restricting the coupling of the Σ and Ξ hyperons to the ω ,ρ , and σ mesons due to the lack of experimental data, and maximum star masses calculated. Conclusions: We conclude that, within a phenomenological relativistic mean field approach, the currently available hypernuclei experimental data and the lack of constraints on the asymmetric equation of state of nuclear matter at high densities set only a limited number of constraints on the neutron star matter equation of state using the recent 2 M⊙ observations. It is shown that the Λ potential in symmetric nuclear matter takes a value of ˜30 -32 Me

  13. Positivity constraints for pseudolinear massive spin-2 and vector Galileons

    NASA Astrophysics Data System (ADS)

    Bonifacio, James; Hinterbichler, Kurt; Rosen, Rachel A.

    2016-11-01

    We derive analyticity constraints on a nonlinear ghost-free effective theory of a massive spin-2 particle known as pseudolinear massive gravity, and on a generalized theory of a massive spin-1 particle, both of which provide simple IR completions of Galileon theories. For pseudolinear massive gravity we find that, unlike de Rham, Gabadadze, and Tolley massive gravity, there is no window of parameter space which satisfies the analyticity constraints. For massive vectors which reduce to Galileons in the decoupling limit, we find that no two-derivative actions are compatible with positivity but that higher derivative actions can be made compatible.

  14. The Massive Star Population in M101

    NASA Astrophysics Data System (ADS)

    Grammer, Skyler; Humphreys, R. M.

    2014-01-01

    An increasing number of non-terminal giant eruptions are being observed by modern supernova and transient surveys. But very little is known about the origin of these giant eruptions and their progenitors, many of which are presumably very massive, evolved stars. Motivated by the small number of progenitors positively associated with these giant eruptions, we have begun a survey of the evolved massive star populations in nearby galaxies. The nearby, nearly face on, giant spiral M101 is an excellent laboratory for studying a large population of very massive stars and their environments. Using archival Hubble Space Telescope (HST) Advanced Camera For Surveys (ACS) data, we have produced a catalog of luminous stars with photometric errors <10% for V < 24.5 and 50% completeness down to V = 26.5 even in regions of high stellar crowding. Using the HST/ACS catalog, we have examined the 100 Myr star formation history (SFH) of the massive star population in M101. We examine how the build up of stars over the last 100 Myrs has proceeded both radially in the disk, and in the spiral arms and inter- arms. Our results indicate the presence of a radial age gradient in the disk with the youngest stars occurring at smaller radii. Comparing the SFHs in the arms to the inter-arms, we find that the star formation rates (SFR) are higher in the arms, by ˜ 1 dex, over the 100 Myr time. The cumulative star formation functions in the arm and inter-arms do not differ appreciably suggesting the arm and inter-arm populations have evolved coevally. We have determined the light curves for a large sample of the massive stars in M101 from the Large Binocular Telescope (LBT) nearby galaxy monitoring program. We have also obtained spectra of the visually brightest and most luminous variable sources with the multiple object spectrograph Hectospec on the Multiple Mirror Telescope and with the Multiple Object Dual Spectrograph on the LBT.

  15. The Rb problem in massive AGB stars.

    NASA Astrophysics Data System (ADS)

    Pérez-Mesa, V.; García-Hernández, D. A.; Zamora, O.; Plez, B.; Manchado, A.; Karakas, A. I.; Lugaro, M.

    2017-03-01

    The asymptotic giant branch (AGB) is formed by low- and intermediate-mass stars (0.8 M_{⊙} < M < 8 M_{⊙}) in their last nuclear-burning phase, when they develop thermal pulses (TP) and suffer extreme mass loss. AGB stars are the main contributor to the enrichment of the interstellar medium (ISM) and thus to the chemical evolution of galaxies. In particular, the more massive AGB stars (M > 4 M_{⊙}) are expected to produce light (e.g., Li, N) and heavy neutron-rich s-process elements (such as Rb, Zr, Ba, Y, etc.), which are not formed in lower mass AGB stars and Supernova explosions. Classical chemical analyses using hydrostatic atmospheres revealed strong Rb overabundances and high [Rb/Zr] ratios in massive AGB stars of our Galaxy and the Magellanic Clouds (MC), confirming for the first time that the ^{22}Ne neutron source dominates the production of s-process elements in these stars. The extremely high Rb abundances and [Rb/Zr] ratios observed in the most massive stars (specially in the low-metallicity MC stars) uncovered a Rb problem; such extreme Rb and [Rb/Zr] values are not predicted by the s-process AGB models, suggesting fundamental problems in our present understanding of their atmospheres. We present more realistic dynamical model atmospheres that consider a gaseous circumstellar envelope with a radial wind and we re-derive the Rb (and Zr) abundances in massive Galactic AGB stars. The new Rb abundances and [Rb/Zr] ratios derived with these dynamical models significantly resolve the problem of the mismatch between the observations and the theoretical predictions of the more massive AGB stars.

  16. Placing Observational Constraints on Massive Star Models

    NASA Astrophysics Data System (ADS)

    Rosenfield, Philip

    2011-10-01

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

  17. 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.

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

    SciTech Connect

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

    2016-04-11

    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 similar or equal to 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 similar or equal to 0.9 (low-z background) and z(median) similar or equal to 1.8 (high-z background). Stacking these populations, we detect the magnification bias effect at 3.3 sigma and 1.3 sigma 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. 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. resulting from the photometric noise and bias, the cluster galaxy contamination and the estimations of the background properties. The resulting. for the combined background populations with 1 sigma 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 eta 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.

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

    NASA Astrophysics Data System (ADS)

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

    2008-06-01

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

  20. Uterine Rupture with Massive Late Postpartum Hemorrhage due to Placenta Percreta Left Partially In Situ

    PubMed Central

    Salman, Mehmet Coskun; Calis, Pinar; Deren, Ozgur

    2013-01-01

    Placental adhesive disorders involve the growth of placental tissue into or through the uterine wall. Among these disorders, placenta percreta is the rarest one. However, it may cause significant complications. This report aimed to report a neglected patient with placenta percreta who developed uterine rupture with life-threatening late postpartum intra-abdominal hemorrhage. On admission, the patient had acute abdomen with moderate abdominal distention and was subjected to emergency laparotomy. A full-thickness defect of the anterior uterine wall involving the hysterotomy site was seen. Placental tissues occupied both sides of the incision and posterior bladder wall was also invaded by placenta. Total abdominal hysterectomy with partial resection of the posterior bladder wall was performed. PMID:24392232

  1. Massive intravenous manganese overdose due to compounding error: minimal role for hemodialysis.

    PubMed

    Hines, Elizabeth Quaal; Soomro, Irfana; Howland, Mary Ann; Hoffman, Robert S; Smith, Silas W

    2016-07-01

    Manganese-associated parkinsonism is well described in occupational settings, in chronic methcathinone users, and in patients receiving long-term total parenteral nutrition. We present a unique case of acute intravenous manganese poisoning with a systematic evaluation of hemodialysis efficacy. A 52-year-old woman was inadvertently administered a single intravenous dose of 800 mg compounded manganese chloride at an outpatient chelation center. In an attempt to minimize central nervous system (CNS) manganese deposition, she underwent urgent hemodialysis followed by five days of therapy with calcium disodium EDTA (1 g/m(2) over eight hours daily). Her initial whole blood manganese concentration, obtained six hours after exposure and prior to treatment, was 120 mcg/L (2.19 micromol/L); normal <5 mcg/L (< 0.09 micromol/L). Following the first four-hour hemodialysis session her blood manganese concentration decreased to 20 mcg/L (0.36 micromol/L). Despite the fall in her blood manganese concentration, analysis of dialysate revealed a total elimination of only 604 mcg (11 micromol) manganese (∼1.4% of manganese burden). Although she remained asymptomatic, an MRI on hospital day two revealed T1 hyperintensities within the bilateral globus pallidi, consistent with manganese exposure. Manganese poisoning is associated with irreversible neurologic toxicity. Hemodialysis did not appear to significantly enhance elimination in this case of acute intravenous manganese toxicity, beyond supportive care and calcium disodium EDTA chelation.

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

    SciTech Connect

    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.

    2016-02-18

    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 observed magnification bias profiles to estimate the multiplicative factor η that describes the ratio of the weak lensing mass to the mass inferred from the SZE observable-mass relation. We further quantify systematic uncertainties in η resulting from the photometric noise and bias, the cluster galaxy contamination and the estimations of the background properties. The resulting η for the combined background populations with 1σ uncertainties is 0.83 ± 0.24(stat) ± 0.074(sys), indicating good consistency between the lensing and the SZE-inferred masses. We also use our best-fit η to predict the weak lensing shear profiles and compare these predictions with observations, showing agreement between the magnification and shear mass constraints. Our work demonstrates the promise of using the magnification as a complementary method to estimate cluster masses in large surveys.

  3. 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.; ...

    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

  4. Acute kidney injury, hyperbilirubinemia, and ischemic skin necrosis due to massive sulindac overdose.

    PubMed

    Vaughn, John L; Shah, Kejal V; Ghossein, Maroun M; Meyer, William L; Kirkpatrick, Robert B

    2015-01-01

    Sulindac is a long-acting nonsteroidal anti-inflammatory drug (NSAID) widely used for the management of osteoarthritis, rheumatoid arthritis, ankylosing sponydlitis, and acute gouty arthritis. Reports of sulindac toxicity in the literature are rare. We report the case of a 22-year old male with a history of bipolar disorder who was brought to the emergency department after ingesting approximately 15 g of sulindac in a suicide attempt. He was found to have acute kidney injury and hyperbilirubinemia. Despite aggressive fluid resuscitation, his renal function progressively worsened requiring the initiation of hemodialysis. Ten days following ingestion of sulindac, he began to develop ischemic skin changes with a gangrenous appearance in his hands and feet. He continued to receive supportive treatment, and his acute kidney injury, hyperbillirubinemia, and ischemic skin necrosis eventually resolved. Clinicians should be aware of this long-acting NSAID and its ability to cause prolonged multisystem organ dysfunction.

  5. HCN hyperfine ratio analysis of massive molecular clumps

    NASA Astrophysics Data System (ADS)

    Schap, W. J.; Barnes, P. J.; Ordoñez, A.; Ginsburg, A.; Yonekura, Y.; Fukui, Y.

    2017-03-01

    We report a new analysis protocol for HCN hyperfine data, based on the PYSPECKIT package, and results of using this new protocol to analyse a sample area of seven massive molecular clumps from the Census of High- and Medium-mass Protostars (CHaMP) survey, in order to derive maps of column density for this species. There is a strong correlation between the HCN integrated intensity, IHCN, and previously reported I_HCO+ in the clumps, but I_N_{2H+} is not well correlated with either of these other two 'dense gas tracers'. The four fitted parameters from PYSPECKIT in this region fall in the range of VLSR = 8-10 km s-1, σV = 1.2-2.2 km s-1, Tex = 4-15 K, and τ = 0.2-2.5. These parameters allow us to derive a column density map of these clouds, without limiting assumptions about the excitation or opacity. A more traditional (linear) method of converting IHCN to total mass column gives much lower clump masses than our results based on the hyperfine analysis. This is primarily due to areas in the sample region of low I, low Tex, and high τ. We conclude that there may be more dense gas in these massive clumps not engaged in massive star formation than previously recognized. If this result holds for other clouds in the CHaMP sample, it would have dramatic consequences for the calibration of the Kennicutt-Schmidt star formation laws, including a large increase in the gas depletion time-scale in such regions.

  6. 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.

  7. Use of a condom to control massive postpartum hemorrhage.

    PubMed

    Akhter, Sayeba; Begum, Mosammat Rashida; Kabir, Zakia; Rashid, Maliha; Laila, Tarafder Runa; Zabeen, Fahmida

    2003-09-11

    To evaluate the efficacy of a condom as a tamponade for intrauterine pressure to stop massive postpartum hemorrhage (PPH). This prospective study was done in the Obstetrics and Gynecology Department of Dhaka Medical College and Hospital, Bangladesh, between July 2001 and December 2002. During the study period, 152 cases of PPH were identified; 109 were managed medically; 20 were managed using the B-Lynch procedure, and 23 were managed using the condom catheter. Patients were selected for intervention with the condom catheter when PPH that occurred as a result of atonicity or morbid adhesion (accreta) could not be controlled by uterotonics or a surgical procedure. In patients who were in shock due to massive hemorrhage, a condom catheter was introduced immediately without prior medical management. With aseptic precautions, a sterile rubber catheter fitted with a condom was introduced into the uterus. The condom was inflated with 250-500 mL normal saline, according to need. The condom catheter was kept for 24-48 hours, depending upon the initial intensity of blood loss, and gradually deflated when bleeding ceased. (1) Ability of condom catheter to stop bleeding; (2) time required to stop bleeding after the tamponade was applied; (3) subsequent morbidity in terms of severe infection, despite use of prophylactic antibiotics. In all 23 cases in which the condom catheter was used, bleeding stopped within 15 minutes. No patient needed further intervention. No patient went into irreversible shock. There was no intrauterine infection as documented by clinical signs and symptoms and culture and sensitivity of high vaginal swab. The hydrostatic condom catheter can control PPH quickly and effectively. It is simple to use, inexpensive, and safe. In developing countries where PPH remains a primary cause of maternal mortality, any healthcare provider involved in delivery may use this procedure for controlling massive PPH to save the lives of patients.

  8. [Small bowel obstruction secondary to massive hookworm infestation complicated by fatal plurimicrobial bacteriemia].

    PubMed

    Mémain, N; Ben M'Rad, M; Rouvier, P; Pallot, J-L

    2016-10-01

    Intestinal symptoms (cramping, flatulence) and iron deficient anemia are classical presenting manifestations of duodenal hookworm infestation in patients living in endemic area. We report a 45-year-old immunocompetent metropolitan man who presented with intestinal obstruction secondary to massive hookworm infestation complicated by fatal plurimicrobial bacteriemia with refractory septic shock. We report a case of acute surgical abdominal presentation with septicemia and refractory shock syndrome due to ileal translocation secondary to massive hookworm infestation. To the best of our knowledge, such a case has not yet been reported. Copyright © 2016. Published by Elsevier SAS.

  9. Renormalization of massive Feynman amplitudes and homogeneity (based on a joint work with Raymond Stora)

    NASA Astrophysics Data System (ADS)

    Nikolov, Nikolay M.

    2016-11-01

    We propose a new renormalization procedure to all orders in perturbation theory, which is formulated on an extended position space. This allows us to apply methods from massless Quantum Field Theory to models of massive fields. These include the technique of homogeneous and associate homogeneous distributions for the extension problem contained in the renormalization theory on position space. This also makes it possible to generalize the notion of residues of Feynman amplitudes, which characterize the presence of additional scales due to renormalization, to the massive case.

  10. 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.

  11. Massively Parallel Algorithms for Solution of Schrodinger Equation

    NASA Technical Reports Server (NTRS)

    Fijany, Amir; Barhen, Jacob; Toomerian, Nikzad

    1994-01-01

    In this paper massively parallel algorithms for solution of Schrodinger equation are developed. Our results clearly indicate that the Crank-Nicolson method, in addition to its excellent numerical properties, is also highly suitable for massively parallel computation.

  12. Cosmological viability of massive gravity with generalized matter coupling

    SciTech Connect

    Solomon, Adam R.; Enander, Jonas; Mörtsell, Edvard; Akrami, Yashar; Koivisto, Tomi S.; Könnig, Frank E-mail: enander@fysik.su.se E-mail: tomi.koivisto@nordita.org E-mail: edvard@fysik.su.se

    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.

  13. 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

  14. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  16. 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.

  17. 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.

  18. Superdense massive galaxies in the nearby universe

    NASA Astrophysics Data System (ADS)

    Ferré-Mateu, Anna; Trujillo, Ignacio

    2010-04-01

    At high-z the most superdense massive galaxies are supposed to be the result of gas-rich mergers resulting in compact remnant (Khochfar & Silk (2006); Naab et al. (2007)). After this, dry mergers are expected to be the mechanism that moves these very massive galaxies towards the current stellar mass size relation. Whitin these 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 past universe.Using the NYU Value-Added Galaxy Catalog (DR6), we find only a tiny fraction of galaxies (~0.03%) with re ≤ 1.5 kpc and M* ≥ 8x1010M⊙ in the local Universe (z~0.2). Surprisingly, they are relatively young (~2Gyr) and metal rich ([Z/H]~0.2) These results have been published in Trujillo et al. (2009)

  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. 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.

  1. 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.

  2. Cyg X-1 - A massive neutron star

    NASA Technical Reports Server (NTRS)

    Goldman, I.

    1981-01-01

    The expected X-ray emission from Cyg X-1, considered a massive neutron star (8-15 solar masses) according to some gravity theories, is studied within the framework of Rosen's bimetric gravity theory (1973, 1974). It is shown that in such massive neutron stars, the innermost stable orbit lies far outside the star surface, and therefore the X-ray spectrum consists of two components: a soft one emitted from a cold accretion disk and a hard one emitted by the matter striking the neutron star surface after spiraling down freely from the disk. The proposed model is shown to be in good agreement with the observed luminosities. The model predicts a surface gravitational redshift of 3.16 which could be tested by the future X- and gamma-ray detectors.

  3. Massive higher spins from BRST and tractors

    NASA Astrophysics Data System (ADS)

    Grigoriev, Maxim; Waldron, Andrew

    2011-12-01

    We obtain the higher spin tractor equations of motion conjectured by Gover et al. from a BRST approach and use those methods to prove that they describe massive, partially massless and massless higher spins in conformally flat backgrounds. The tractor description makes invariance under local choices of unit systems manifest. In this approach, physical models are described by conformal, rather than (pseudo-)Riemannian geometry. In particular masses become geometric quantities, namely the weights of tractor fields. Massive models can therefore be handled in a unified and simple manner mimicking the gauge principle usually employed for massless models. From a holographic viewpoint, these models describe both the bulk and boundary theories in terms of conformal geometry. This is an important advance, because tying the boundary conformal structure to that of the bulk theory gives greater control over a bulk-boundary correspondence.

  4. Recent massive star formation in 30 Doradus

    SciTech Connect

    Walborn, N.R.; Blades, J.C.

    1987-12-01

    Two early O-type stars apparently involved in dense nebular knots have been found in the northeast quadrant of the 30 Doradus nebula. One of them lies within the positional uncertainty radius of a previously detected water maser source, and it has a well-marked interstellar 4430 A diffuse band feature. These objects may be very young massive stars just emerging from their protostellar cocoons, and it is suggested that this part of 30 Doradus may represent an earlier evolutionary stage than the central region surrounding R136. A brief survey of recent literature on possibly related objects in the Magellanic Clouds suggests the emergence there of a class corresponding to optically observable, very early evolutionary stages of massive stars. 21 references.

  5. More on massive 3D gravity

    SciTech Connect

    Bergshoeff, Eric A.; Hohm, Olaf; Townsend, Paul K.

    2009-06-15

    We explore the space of static solutions of the recently discovered three-dimensional 'new massive gravity' (NMG), allowing for either sign of the Einstein-Hilbert term and a cosmological term parametrized by a dimensionless constant {lambda}. For {lambda}=-1 we find black hole solutions asymptotic (but not isometric) to the unique (anti) de Sitter [(A)dS] vacuum, including extremal black holes that interpolate between this vacuum and (A)dS{sub 2}xS{sup 1}. We also investigate unitarity of linearized NMG in (A)dS vacua. We find unitary theories for some dS vacua, but (bulk) unitarity in AdS implies negative central charge of the dual conformal field theories (CFT), except for {lambda}=3 where the central charge vanishes and the bulk gravitons are replaced by 'massive photons'. A similar phenomenon is found in the massless limit of NMG, for which the linearized equations become equivalent to Maxwell's equations.

  6. 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.

  7. Stable FLRW solutions in generalized massive gravity

    NASA Astrophysics Data System (ADS)

    de Rham, Claudia; Fasiello, Matteo; Tolley, Andrew J.

    2014-12-01

    We present exact Friedmann Lemaítre Robertson Walkers (FLRW) solutions in generalized massive gravity where the mass parameters are naturally promoted to Lorentz-invariant functions of the Stückelberg fields. This new dependence relaxes the constraint that would otherwise prevent massive gravity from possessing exact FLRW solutions. It does so without the need to introduce additional degrees of freedom. We find self-accelerating cosmological solutions and show that, with a mild restriction on the region of phase space, these cosmological solutions exhibit full stability, i.e. absence of ghosts and gradient instabilities for all the tensor, vector and scalar modes, for all cosmic time. We perform the full decoupling limit analysis, including vector degrees of freedom, which can be used to confirm the existence of an active Vainshtein mechanism about these solutions.

  8. Dynamical symmetry enhancement near massive IIA horizons

    NASA Astrophysics Data System (ADS)

    Gran, U.; Gutowski, J.; Kayani, U.; Papadopoulos, G.

    2015-12-01

    We prove that Killing horizons in massive IIA supergravity preserve an even number of supersymmetries, and that their symmetry algebra contains an {sl}(2,{{R}}) subalgebra, confirming the conjecture of Gran et al (2013 J. High Energy Phys. JHEP11(2013)104). We also prove a new class of Lichnerowicz-type theorems for connections of the spin bundle whose holonomy is contained in a general linear group.

  9. Theoretical Developments in Understanding Massive Star Formation

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.; Bodenheimer, Peter

    2007-01-01

    Except under special circumstances massive stars in galactic disks will form through accretion. The gravitational collapse of a molecular cloud core will initially produce one or more low mass quasi-hydrostatic objects of a few Jupiter masses. Through subsequent accretion the masses of these cores grow as they simultaneously evolve toward hydrogen burning central densities and temperatures. We review the evolution of accreting (proto-)stars, including new results calculated with a publicly available stellar evolution code written by the authors.

  10. 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.

  11. 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.

  12. Spontaneous Resolution of Massive Spontaneous Tubercular Pneumothorax

    PubMed Central

    Kant, Surya; Saheer, S.; Hassan, G.; Parengal, Jabeed

    2011-01-01

    A 29-year-old female presented with complaints of fever and productive cough of three weeks duration. Pulmonary tuberculosis was diagnosed bacteriologically and she was prescribed antituberculosis drugs. During follow-up she developed massive pneumothorax, for which patient refused surgical management and was managed conservatively. After six months there was complete spontaneous resolution of pneumothorax. The unusual presentation and unexpected outcome prompted us to report this case. PMID:22937428

  13. 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.

  14. The theory of Minimal Massive Gravity

    NASA Astrophysics Data System (ADS)

    De Felice, Antonio

    2017-08-01

    Here we give a short summary of the the theory of minimal massive gravity. This theory, by construction, possesses only two tensor modes, exactly as in General Relativity. This theory is able to reconcile the original background of dRGT - which was proven to possess a ghost - with a stable homogeneous and isotropic cosmological evolution. The theory is constructed by imposing two constraints in a non-linear, background-independent way. The phenomenology of the theory is also briefly discussed.

  15. Theoretical Developments in Understanding Massive Star Formation

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.; Bodenheimer, Peter

    2007-01-01

    Except under special circumstances massive stars in galactic disks will form through accretion. The gravitational collapse of a molecular cloud core will initially produce one or more low mass quasi-hydrostatic objects of a few Jupiter masses. Through subsequent accretion the masses of these cores grow as they simultaneously evolve toward hydrogen burning central densities and temperatures. We review the evolution of accreting (proto-)stars, including new results calculated with a publicly available stellar evolution code written by the authors.

  16. Massive 3D gravity Big Bounce

    NASA Astrophysics Data System (ADS)

    Louzada, H. L. C.; Camara Ds, U.; Sotkov, G. M.

    2010-03-01

    The properties of an extension of the new massive 3D gravity by scalar matter with Higgs-like self-interaction are investigated. Its perturbative unitarity consistency is verified for a family of cosmological bounce solutions found by the superpotential method. They correspond to the lower bound λ=-1 of the BHT unitarity window and describe eternally accelerated 3D Universe between two initial/final stable dS vacua states.

  17. Massive higher spins in d = 3 unfolded

    NASA Astrophysics Data System (ADS)

    Zinoviev, Yu M.

    2016-03-01

    In this paper we construct an unfolded formulation for the massive bosonic higher spins in three dimensions as well as for their partially massless limit of the maximal depth. We begin with the equations for the one-forms coming from the frame-like gauge invariant Lagrangians for such fields and then we supplement them with an infinite number of equations for the appropriately chosen set of zero-forms.

  18. 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.

  19. THE STELLAR HALOS OF MASSIVE ELLIPTICAL GALAXIES

    SciTech Connect

    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'' Multiplication-Sign 107''), allowing us to achieve remarkably high signal-to-noise ratios of {approx}20-70 pixel{sup -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 {sigma}{sub *} > 150 km s{sup -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 {approx}50%, and only a weak correlation between {sigma}{sub *} and Mgb EW remains. The Mgb EWs at large radii are comparable to those seen in the centers of elliptical galaxies that are {approx} 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 R{sub e} , 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 {alpha}-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.

  20. On 3D minimal massive gravity

    NASA Astrophysics Data System (ADS)

    Alishahiha, Mohsen; Qaemmaqami, Mohammad M.; Naseh, Ali; Shirzad, Ahmad

    2014-12-01

    We study linearized equations of motion of the newly proposed three dimensional gravity, known as minimal massive gravity, using its metric formulation. By making use of a redefinition of the parameters of the model, we observe that the resulting linearized equations are exactly the same as that of TMG. In particular the model admits logarithmic modes at critical points. We also study several vacuum solutions of the model, specially at a certain limit where the contribution of Chern-Simons term vanishes.

  1. 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.

  2. 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.

  3. The cosmic assembly of stellar haloes in massive Early-Type Galaxies

    NASA Astrophysics Data System (ADS)

    Buitrago, Fernando; Trujillo, Ignacio; Curtis-Lake, Emma; Montes, Mireia; Cooper, Andrew P.; Bruce, Victoria A.; Pérez-González, Pablo G.; Cirasuolo, Michele

    2017-01-01

    Using the exquisite depth of the Hubble Ultra Deep Field (HUDF12 programme) dataset, we explore the ongoing assembly of the outermost regions of the most massive galaxies (M_stellar≥5× 1010 M⊙) at z ≤ 1. The outskirts of massive objects, particularly Early-Types Galaxies (ETGs), are expected to suffer a dramatic transformation across cosmic time due to continuous accretion of small galaxies. HUDF imaging allows us to study this process at intermediate redshifts in 6 massive galaxies, exploring the individual surface brightness profiles out to ˜25 effective radii. We find that 5-20% of the total stellar mass for the galaxies in our sample is contained within 10 Massive Early-Type Galaxies increases with decreasing redshift, being 28.7% at = 0.1, 15.1% at = 0.65 and 3.5% at = 2. The fraction of mass in diffuse features linked with ongoing minor merger events is > 1-2%, very similar to predictions based on observed close pair counts. Therefore, the results for our small albeit meaningful sample suggest that the size and mass growth of the most massive galaxies have been solely driven by minor and major merging from z = 1 to today.

  4. Observational constraints on massive-star evolution

    NASA Astrophysics Data System (ADS)

    Schulte-Ladbeck, Regina

    1997-07-01

    Massive stars are important constitutents of galaxies and are increasingly used as probes of galaxy evolution out to high redshifts. Yet, a very basic problem remains in understanding the distribution of massive stars across the Hertzsprung- Russell Diagram. This is known as the problem of the blue-to- red supergiant ratios in galaxies of different metallicities, a very sensitive indicator of the evolutionary paths that massive stars in different chemical environments appear to follow. Observations suggest a trend that the numbers of red supergiants increase with decreasing metallicity, but stellar- evolution models predict the opposite. We discuss various limitations of ground-based observations which have so far restricted accurate star counts to a few, nearby galaxies. We then argue that the HST archive contains a perfect set of photometric data to determine number counts of red supergiants in galaxies out to 5 Mpc. We propose to analyze WFPC2 observations in F555W {V} and F814W {I} filters to derive color-magnitude diagrams and complete luminosity functions of the red supergiant populations in 6 galaxies spanning a factor of 60 in metallicity. This systematic approach will put the functional form of the blue-to-red supergiant ratio with metallicity on firm observational footing.

  5. Massive ovarian oedema: a misleading clinical entity.

    PubMed

    Machairiotis, Nikolaos; Stylianaki, Aikaterini; Kouroutou, Paraskevi; Sarli, Polixeni; Alexiou, Nikolaos Konstantinos; Efthymiou, Elias; Maras, Athanasios; Alexiou, Nikolaos Georgios; Nikolaou, Spyridon Evaggelos; Courcoutsakis, Nikolaos; Papakonstantinou, Eleni; Zarogoulidis, Paul; Barbetakis, Nikolaos; Paliouras, Dimitrios; Gogakos, Apostolos; Machairiotis, Christodoulos

    2016-02-03

    Massive ovarian oedema is a rare non-neoplastic clinicopathologic entity has a higher incidence in women during their second and third life decade. The oedema can be presented in one or both ovaries as a result of partial intermittent torsion of the ovarian pedicle that interferes to the venal and lymphatic drainage of the ovary. We present a clinical case of a 16 year old with massive ovarian oedema and we performed a review of the literature. The pathophysiology of this entity is very complex. We tried to perform a complete review of the literature and focus on the complexity of this entity as far as its pathophysiological backround is concerned and as far as its clinical presentation is concerned. In conclusion, massive ovarian oedema is a rare, multi disease mimicking clinical entity, with an acute or progressive clinical presentation. It has also to be a part of our differential diagnosis in cases of acute abdominal pain and we have to try to treat her conservatively, in order to preserve fertility.

  6. 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.

  7. Current management of massive hemorrhage in trauma

    PubMed Central

    2012-01-01

    Hemorrhage remains a major cause of potentially preventable deaths. Trauma and massive transfusion are associated with coagulopathy secondary to tissue injury, hypoperfusion, dilution, and consumption of clotting factors and platelets. Concepts of damage control surgery have evolved prioritizing early control of the cause of bleeding by non-definitive means, while hemostatic control resuscitation seeks early control of coagulopathy. Hemostatic resuscitation provides transfusions with plasma and platelets in addition to red blood cells in an immediate and sustained manner as part of the transfusion protocol for massively bleeding patients. Although early and effective reversal of coagulopathy is documented, the most effective means of preventing coagulopathy of massive transfusion remains debated and randomized controlled studies are lacking. Viscoelastical whole blood assays, like TEG and ROTEM however appear advantageous for identifying coagulopathy in patients with severe hemorrhage as opposed the conventional coagulation assays. In our view, patients with uncontrolled bleeding, regardless of it´s cause, should be treated with hemostatic control resuscitation involving early administration of plasma and platelets and earliest possible goal-directed, based on the results of TEG/ROTEM analysis. The aim of the goal-directed therapy should be to maintain a normal hemostatic competence until surgical hemostasis is achieved, as this appears to be associated with reduced mortality. PMID:22776724

  8. The feeding and feedback of massive protostars

    NASA Astrophysics Data System (ADS)

    Smith, Michael

    2013-07-01

    A model for massive stars is constructed by piecing together evolutionary algorithms for the protostellar structure, the environment, the inflow and the radiation feedback. The framework requires the accretion rate from the clump to be specified. We investigate constant, decelerating and accelerating accretion rate scenarios and consider both hot and cold accretion, identified with spherical free-fall and disk accretion, respectively. We find that accelerated accretion is not favoured on the basis of the often-used diagnostic diagram which correlates the bolometric luminosity and clump mass. Instead, source counts as a function of the bolometric temperature can distinguish the accretion mode. Specifically, accelerated accretion yields a relatively high number of lowtemperatureob jects. On this basis, we demonstrate that evolutionary tracks to fit Herschel Space Telescope data require the generated stars to be three to four times less massive than in previous interpretations. Neither spherical nor disk accretion can explain the high radio luminosities of many protostars. Nevertheless, we discover a solution in which the extreme ultraviolet flux needed to explain the radio emission is produced if the accretion flow is via free-fall on to hot spots covering less than 20% of the surface area. Moreover, the protostar must be compact, and so has formed through cold accretion. This suggest that massive stars form via gas accretion through disks which, in the phase before the star bloats, download their mass via magnetic flux tubes on to the protostar.

  9. Minimal theory of quasidilaton massive gravity

    NASA Astrophysics Data System (ADS)

    De Felice, Antonio; Mukohyama, Shinji; Oliosi, Michele

    2017-07-01

    We introduce a quasidilaton scalar field to the minimal theory of massive gravity with the Minkowski fiducial metric, in such a way that the quasidilaton global symmetry is maintained and that the theory admits a stable self-accelerating de Sitter solution. We start with a precursor theory that contains three propagating gravitational degrees of freedom without a quasidilaton scalar and introduce Stückelberg fields to covariantize its action. This makes it possible for us to formulate the quasidilaton global symmetry that mixes the Stückelberg fields and the quasidilaton scalar field. By the Hamiltonian analysis we confirm that the precursor theory with the quasidilaton scalar contains 4 degrees of freedom, three from the precursor massive gravity and one from the quasidilaton scalar. We further remove one propagating degree of freedom to construct the minimal quasidilaton theory with three propagating degrees of freedom, corresponding to two polarizations of gravitational waves from the minimal theory of massive gravity and one scalar from the quasidilaton field, by carefully introducing two additional constraints to the system in the Hamiltonian language. Switching to the Lagrangian language, we find self-accelerating de Sitter solutions in the minimal quasidilaton theory and analyze their stability. It is found that the self-accelerating de Sitter solution is stable in a wide range of parameters.

  10. Massive star formation at high spatial resolution

    NASA Astrophysics Data System (ADS)

    Pascucci, Ilaria

    2004-05-01

    This thesis studies the early phases of massive stars and their impact on the surrounding. The capabilities of continuum radiative transfer (RT) codes to interpret the observations are also investigated. The main results of this work are: 1) Two massive star-forming regions are observed in the infrared. The thermal emission from the ultra-compact H II regions is resolved and the spectral type of the ionizing stars is estimated. The hot cores are not detected thus implying line-of-sight extinction larger than 200 visual magnitude. 2) The first mid-infrared interferometric measurements towards a young massive star resolve thermal emission on scales of 30-50 AU probing the size of the predicted disk. The visibility curve differs from those of intermediate-mass stars. 3) The close vicinity of Θ1C Ori are imaged using the NACO adaptive optics system. The binary proplyd Orion 168-326 and its interaction with the wind from Θ1C Ori are resolved. A proplyd uniquely seen face-on is also identified. 4) Five RT codes are compared in a disk configuration. The solutions provide the first 2D benchmark and serve to test the reliability of other RT codes. The images/visibilities from two RT codes are compared for a distorted disk. The parameter range in which such a distortion is detectable with MIDI is explored.

  11. Spatial Disrtribution and Evolution of Massive Stars

    NASA Astrophysics Data System (ADS)

    Aghakhanlootakanloo, Mojgan; Murphy, Jeremiah W.

    2017-01-01

    Observations show that luminous blue variables (LBVs) are far more dispersed than other massive stars, and Smith & Tombleson (2015) suggested that these large separations are inconsistent with the standard single-star evolution model of LBVs. Instead, they suggest that the large distances are most consistent with some sort of binary evolution. To test these suggestions, we modeled young stellar clusters and their passive dissolution, and we find that, indeed, the single-star evolution model is inconsistent with observations. Most importantly, we find two binary scenario models that are consistent. Our crude models suggest that LBVs are either the result of mergers and are rejuvenated stars, or they are mass gainers and received a kick when the primary star exploded. In the merger scenario, LBVs have more time to disperse because they are the merger of two lesser mass, in which the primary has a mass of about 19 solar masses. In the mass gainer and kick scenario, we find that LBV isolation is consistent with an average kick of 200 km/s. In either scenario, binarity plays a major role in the isolation of LBVs. In addition to constraining the evolution of LBVs, we suggest that careful scrutiny of the spatial distribution of massive stars in general will lead to a greater understanding for the evolution of massive stars.

  12. Magnetic Field Distribution for Massive Stars

    NASA Astrophysics Data System (ADS)

    Medvedev, A.; Kholtygin, A.

    2017-06-01

    A model of the evolution of an ensemble of magnetic massive stars on the main sequence is developed. We use our own population synthesis code, which allows us to obtain distributions of stars by radii, ages, masses, temperatures, effective magnetic fields, and magnetic fluxes from the pre-main sequence up to the TAMS stages. We assume that magnetic fields in massive stars decrease with time. The rate of magnetic field dissipation may depend on the mass of a star on ZAMS. The distribution of magnetic fluxes of the ZAMS stars is assumed to be log-normal. We show that such kind of distribution may be a result of the dynamo action occurring at the pre-MS evolutionary stage of magnetic stars. Our model also includes capabilities for statistical simulations and parameter estimation necessary for the analysis of real data. Comparison of model magnetic field distributions with those obtained from recent measurements of stellar magnetic fields allows us to conclude that the evolution of magnetic fields of massive stars is very slow if not absent. The shape of the real magnetic field distribution has no indications of the “magnetic desert,” previously suggested by Lignieres et al. (2014). Based on those findings we argue that the observed fraction of magnetic stars is determined only by physical conditions at early stages of stellar evolution.

  13. Massive-Star Nucleosynthesis: Lessons from INTEGRAL

    NASA Astrophysics Data System (ADS)

    Diehl, Roland; Lang, Michael; Kretschmer, Karsten; Martin, Pierrick; Ohlendorf, Henrike; Voss, Rasmus

    2010-08-01

    Gamma-ray line observations with INTEGRAL measure decay of unstable isotopes which are ejected from sites of nucleosynthesis. Massive stars are believed to be producers of gamma-ray emitting isotopes 44Ti, 26Al, 60Fe. Measurements with the Ge spectrometer have shown that (1) inner core-collapse supernova ejecta from the Cas A supernova remnant appear to still travel at velocities beyond a few hundred km/sec (2) 26Al synthesis occurs throughout the Galaxy corresponds to a supernova rate from core collapses of about one every 50 years; (3) 60Fe synthesis expected from massive stars is above the constraints from gamma-ray observations; 26Al synthesis in the Cygnus region appears on the high side of predictions from models; 26Al emission from the nearby Sco-Cen group of stars has been identified demonstrates massive-star activity close to the Sun. 26Al gamma-rays have been used to determine a longitude-velocity distribution of the presumably hot tenuous ISM which carries 26Al, which can be compared to molecular-gas star motions to help understand the Galaxy's bar spiral-arm structure. Implications of the above nucleosynthesis constraints suggest that INTEGRAL's observed positron annihilation gamma-rays need a contribution from another source located in the central regions of our Galaxy, and/or positrons may propagate kpc-distances away from their sources before annihilating.

  14. 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.

  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. Mass Lost from the Most Massive Stars

    NASA Astrophysics Data System (ADS)

    Weis, Kerstin

    2004-02-01

    The structure and evolution of galaxies is noticeably influenced by the energy input of very massive stars. They are not only the supply of heavier elements, they also influence the distribution and structure of the interstellar medium through their strong stellar winds and supernova explosions. Losing more than 50% of their ZAMS-mass during their life, stars more massive than ~ 50 M⊙ substantially contribute to the mass and energy input which can drive large scale outflows from galaxies. In this presentation I will mainly concentrate on a short but violent phase of mass loss of the most massive stars, known as Luminous Blue Variables. In only a few thousand years a large amount of mass is released (in some cases several solar masses), forming a nebula around the LBV. Besides of a general overview of the LBVs special concern will be given to the nebula around eta Carinae for which new results from CHANDRA observations show the shocks emitting in the X-ray band. Finally I will briefly address the question of the role of LBV type stars in the early phase of galaxy formation and in connection with the first stars formed.

  17. On the Formation of Massive Stars

    NASA Astrophysics Data System (ADS)

    Kaper, L.; Ellerbroek, L.; Ochsendorf, B.; Bik, A.

    2012-12-01

    The birth process and (early) evolution of massive stars is still poorly understood. Heavy extinction hides their birthplaces from view and the short formation timescale limits the sample of objects to be studied. So far, our physical knowledge of massive YSOs has been derived from near-IR imaging and spectroscopy, revealing populations of young OB-type stars, some still surrounded by a disk, others apparently ‘normal’ main sequence stars powering H II regions. The most important spectral features of OB-type stars are, however, located in the UV and optical range. With the new optical/near-infrared spectrograph X-shooter on the ESO Very Large Telescope it is possible to extend the spectral coverage of these massive YSOs into the optical range. Our first results are very promising: the discovery of a jet demonstrates that one of our mYSOs is still actively accreting. Furthermore, the first firm spectral classification of another mYSO results in the precise location on a pre-main-sequence track.

  18. Star Formation in the Galactic Center: Massive stars and the ISM in Sgr B

    NASA Astrophysics Data System (ADS)

    Cotera, Angela

    Our Galactic Center (GC) is a unique region that enables detailed studies of a mild starburst nucleus at resolutions unapproachable in other galaxies. The GC provides unparalleled opportunities to test theories of the interrelationship of massive stars, molecular and ionized gas, dust, turbulent giant molecular clouds, large-scale magnetic fields, and a black hole; all under extreme conditions. We propose to use FLITECAM to obtain a Paschen-alpha map extending east from the Radio Arc region (previously observed in Paschen-alpha with HST) out to Sgr B. Made up of two distinct regions (Sgr B1 and Sgr B2), Sgr B is one of the most complex star-forming regions in the Galaxy, containing a massive molecular cloud, dozens of HII regions, and numerous young stellar objects (YSOs). Although much of Sgr B2 is unobservable at IR wavelengths due to extinction, Sgr B1 and the periphery of Sgr B2 have lower extinction making the proposed observations possible in these regions. We further propose to complete our Cycle 3 FORCAST observations of the peak mid-infrared emission in Sgr B1 to investigate the temperature and dust structure within these regions which contain known massive stars and massive YSOs. When combined with existing multi-wavelength observations, we will be able to address crucial questions such as: Where are the young massive stars currently located? Is star formation in our Galactic nucleus fundamentally different due to the extreme conditions in the central 400pc? How does the stellar feedback from massive star formation impact turbulence in giant molecular clouds?

  19. 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.

  20. 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

  1. On the Formation of Massive Stars

    NASA Technical Reports Server (NTRS)

    Yorke, Harold W.; Sonnhalter, Cordula

    2002-01-01

    We calculate numerically the collapse of slowly rotating, nonmagnetic, massive molecular clumps of masses 30,60, and 120 Stellar Mass, which conceivably could lead to the formation of massive stars. Because radiative acceleration on dust grains plays a critical role in the clump's dynamical evolution, we have improved the module for continuum radiation transfer in an existing two-dimensional (axial symmetry assumed) radiation hydrodynamic code. In particular, rather than using "gray" dust opacities and "gray" radiation transfer, we calculate the dust's wavelength-dependent absorption and emission simultaneously with the radiation density at each wavelength and the equilibrium temperatures of three grain components: amorphous carbon particles. silicates, and " dirty ice " -coated silicates. Because our simulations cannot spatially resolve the innermost regions of the molecular clump, however, we cannot distinguish between the formation of a dense central cluster or a single massive object. Furthermore, we cannot exclude significant mass loss from the central object(s) that may interact with the inflow into the central grid cell. Thus, with our basic assumption that all material in the innermost grid cell accretes onto a single object. we are able to provide only an upper limit to the mass of stars that could possibly be formed. We introduce a semianalytical scheme for augmenting existing evolutionary tracks of pre-main-sequence protostars by including the effects of accretion. By considering an open outermost boundary, an arbitrary amount of material could, in principal, be accreted onto this central star. However, for the three cases considered (30, 60, and 120 Stellar Mass originally within the computation grid), radiation acceleration limited the final masses to 3 1.6, 33.6, and 42.9 Stellar Mass, respectively, for wavelength-dependent radiation transfer and to 19.1, 20.1, and 22.9 Stellar Mass. for the corresponding simulations with gray radiation transfer. Our

  2. Molecular Outflows in Massive Star Forming Regions

    NASA Astrophysics Data System (ADS)

    Cunningham, Nichol

    2015-11-01

    This thesis presents millimetre continuum and molecular line observations exploring the properties of molecular outflows towards massive star forming regions. Massive stars produce some of the most energetic phenomena in the Galaxy, yet we still do not have a comprehensive understanding of how they actually form. Outflows are known to play a key role in this formation process and their properties, particularly how they change depending on the mass, luminosity and evolution of the driving source can shed light on how massive stars actually form. This thesis presents observations at both high (SMA 3 arcsecond) and low (JCMT 15 arcsecond) spatial resolution of the known jet/outflow tracers, SiO and 12CO, towards a sample massive star forming region drawn from the RMS survey. Furthermore, the presence of infall signatures is explored through observations of HCO+ and H13CO+, and the hot core nature of the regions is probed using tracers such as CH3CN, HC3N and CH3OH. SiO is detected towards approximately 50% of the massive young stellar objects and HII regions in the JCMT sample. The detection of SiO appears to be linked to the age of the RMS source, with the likely younger sources showing a stronger dependence with SiO. The presence of SiO also appears to be linked to the CO velocity, with SiO more efficiently tracing sources with higher velocity dispersions. In the MOPRA observations towards a sample of 33 RMS sources, CH3CN is detected towards 66% of the sources, with the redder likely younger sources having the largest rotational temperatures. This thesis presents the first interferometric SiO (5-4) and 12CO (2-1) observations, taken with the SMA, towards the massive star forming region G203.3166/NGC 2264-C. In this intermediate/massive star forming cluster, SiO is again tracing the youngest sources. Both the SiO and 12CO emission trace two bipolar, high velocity outflows towards the mm brightest, IR-dark, likely youngest sources in this reg! ion. In contrast the IR

  3. Small Scale Isocurvature Perturbation of Weakly Interacting Massive Particle

    NASA Astrophysics Data System (ADS)

    Choi, Ki-Young; Gong, Jinn-Ouk; Shin, Chang Sub

    2016-07-01

    It is known that the smallest size of the structures of the Universe with the weakly interacting massive dark matter is determined by the scale that enters the Hubble horizon at the time of kinetic decoupling of WIMP. This comes from the fact that the perturbation at smaller scales is erased due to the collisional damping during the kinetic decoupling. However the isocurvature mode is not affected and continue to be constant. We discuss about the generation of the isocurvature mode of WIMP dark matter at small scales recently found by Choi, Gong, and Shin1 and its implications for the indirect detection of dark matter through the formation of the small size of halos.

  4. Mass-varying massive gravity with k-essence

    NASA Astrophysics Data System (ADS)

    Tannukij, Lunchakorn

    2017-08-01

    In this work I review the specific class of mass-varying massive gravity in which a corresponding graviton is given nonzero varying mass. Particularly in this theory, the graviton mass varies which is driven by a rolling k-essence field. Firstly, the model action is expressed along with its equations of motion. It is found from those equations of motion that not only the cosmic accelerating expansion but also the presence of dark matter can be realized in this context. Due to the complexity of its dynamics, the method of dynamical analysis is used to investigate evolutions of the cosmological system. It is found that the corresponding cosmological evolutions can explain the cosmic coincidence problem, where the effective dark matter is presented while the system is in the phase of the cosmic accelerating expansion. I then conclude that the evolutions obtained here can alleviate the cosmic coincidence problem while in some aspects the fine-tuning problem arises.

  5. 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.

  6. Integrated Sachs-Wolfe effect in massive bigravity

    NASA Astrophysics Data System (ADS)

    Enander, Jonas; Akrami, Yashar; Mörtsell, Edvard; Renneby, Malin; Solomon, Adam R.

    2015-04-01

    We study the integrated Sachs-Wolfe (ISW) effect in ghost-free, massive bigravity. We focus on the infinite-branch bigravity (IBB) model which exhibits viable cosmic expansion histories and stable linear perturbations, while the cosmological constant is set to zero and the late-time accelerated expansion of the Universe is due solely to the gravitational interaction terms. The ISW contribution to the CMB auto-correlation power spectrum is predicted, as well as the cross-correlation between the CMB temperature anisotropies and large-scale structure. We use ISW amplitudes as inferred from the WMAP 9-year temperature data together with galaxy and AGN data provided by the WISE mission in order to compare the theoretical predictions to the observations. The ISW amplitudes in IBB are found to be larger than the corresponding ones in the standard Λ CDM model by roughly a factor of 1.5, but are still consistent with the observations.

  7. 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.

  8. 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

  9. Extreme Star Formation in the Massive Young Cluster Westerlund 1

    NASA Astrophysics Data System (ADS)

    Hora, Joseph; Kraemer, Kathleen; Megeath, Tom; Gutermuth, Rob; Smith, Howard; Martinez Galarza, Juan Rafael; Guzman Fernandez, Andres; Carey, Sean; Koenig, Xavier; Schneider, Nicola; Motte, Frederique; Bontemps, Sylvain; Adams, Joseph; Simon, Robert; Nguyen-Luong, Quang; Schilke, Peter; Keto, Eric; Fazio, Giovanni; Allen, Lori

    2012-12-01

    We propose to extend Spitzer's study of massive star formation to the massive cluster Westerlund 1, which at ~4 kpc is the closest and most massive 'Super Star Cluster' known in the Galaxy. Star formation may have proceeded differently in this region, having created a higher overall density of coeval massive stars. The proposed observations will allow us to compare star formation in this region to that seen near the Sun, in the massive Cygnus-X complex, and in the outer Galaxy (coming from the studies of W5, the Cycle-5 SMOG project, and GLIMPSE360), and therefore to complete a more representative view of star formation in the Galaxy.

  10. Modeling the Asymmetric Wind of Massive LBV Binary MWC 314

    NASA Astrophysics Data System (ADS)

    Lobel, A.; Groh, J.; Torres Dozinel, K.; Gorlova, N.; Martayan, C.; Raskin, G.; Van Winckel, H.; Prins, S.; Pessemier, W.; Waelkens, C.; Frémat, Y.; Hensberge, H.; Dummortier, L.; Jorissen, A.; Van Eck, S.; Lehmann, H.

    2012-12-01

    Spectroscopic monitoring with Mercator-HERMES over the past two years reveals that MWC 314 is a massive binary system composed of an early B-type primary LBV star and a less-luminous supergiant companion. We determine an orbital period Porb of 60.85 d from optical S II and Ne I absorption lines observed in this single-lined spectroscopic binary. We find an orbital eccentricity of e = 0.26, and a large amplitude of the radial velocity curve of 80.6 km s-1. The ASAS V light-curve during our spectroscopic monitoring reveals two brightness minima (ΔV = 0.1 mag) over the orbital period due to partial eclipses at an orbital inclination angle of ˜ 70°. We find a clear correlation between the orbital phases and the detailed shapes of optical and near-IR P Cygni-type line profiles of He I, Si II, and double- or triple-peaked stationary cores of prominent Fe II emission lines. A preliminary 3-D radiative transfer model computed with Wind3D shows that the periodic P Cygni line profile variability results from an asymmetric common-envelope wind with enhanced density (or line opacity) in the vicinity of the LBV primary. The variable orientation of the inner LBV wind region due to the orbital motion produces variable P Cygni line profiles (with wind velocities of ˜ 200 km s-1) between orbital phases φ = 0.65 to 0.85, while weak inverse P Cygni profiles are observed half an orbital period later around φ = 0.15 to 0.35. We do not observe optical or near-IR He II, C III, and Si III lines, signaling that the LBV's spectral type is later than B0. Detailed modeling of the asymmetrical wind properties of massive binary MWC 314 provides important new physical information about the most luminous hot (binary) stars such as η Carinae.

  11. 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.

  12. Transverse Instability of Line Solitary Waves in Massive Dirac Equations

    NASA Astrophysics Data System (ADS)

    Pelinovsky, Dmitry; Shimabukuro, Yusuke

    2016-04-01

    Working in the context of localized modes in periodic potentials, we consider two systems of the massive Dirac equations in two spatial dimensions. The first system, a generalized massive Thirring model, is derived for the periodic stripe potentials. The second one, a generalized massive Gross-Neveu equation, is derived for the hexagonal potentials. In both cases, we prove analytically that the line solitary waves are spectrally unstable with respect to periodic transverse perturbations of large periods. The spectral instability is induced by the spatial translation for the generalized massive Thirring model and by the gauge rotation for the generalized massive Gross-Neveu model. We also observe numerically that the spectral instability holds for the transverse perturbations of any period in the generalized massive Thirring model and exhibits a finite threshold on the period of the transverse perturbations in the generalized massive Gross-Neveu model.

  13. 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.

  14. Thrombolytic treatment (alteplase; rt-Pa) in acute massive pulmonary embolism and cardiopulmonary arrest.

    PubMed

    Dirican, Adem; Ozkaya, Sevket; Atas, Ali Ekber; Ulu, Esra Kayahan; Kitapci, Ilknur; Ece, Ferah

    2014-01-01

    Patients with pulmonary thromboembolism (PE) often decompensate suddenly, and once hemodynamic compromise has developed, mortality is extremely high. Currently, thrombolytic therapy for PE is still controversial. We retrospectively evaluated 34 patients with PE between January 2010 and December 2013 in the Department of Pulmonary Medicine, Medical Park Samsun Hospital, Samsun, Turkey. The demographic and disease characteristics of patients who received thrombolytic treatment were retrospectively analyzed. The female to male ratio was 19/15 and the mean age was 63.1±13.2 years. PE diagnosis was made using echocardiography (64.7%) or contrast-enhanced thorax computed tomography with echocardiography (32.4%). Twenty-two (64.7%) patients went into the cardiopulmonary arrest due to massive PE and 17 (50%) patients recovered without sequelae. Eleven (32.4%) patients were diagnosed with massive PE during cardiopulmonary arrest with clinical and echocardiographic findings. Alteplase (recombinant tissue plasminogen activator [rt-PA]) was administered during cardiopulmonary resuscitation (CPR) and four (36.3%) patients responded and survived without sequelae. The complications of rt-PA treatment were hemorrhage in five (14.7%) patients and allergic reactions in two (5.9%) patients. There was no mortality due to rt-PA treatment complications. In conclusion, mortality due to massive PE is much more than estimated and alteplase can be used safely in patients with massive PE. This thrombolytic treatment was not associated with any fatal hemorrhage complication. If there is any sign of acute PE, echocardiography should be used during cardiopulmonary arrest/instability. Alteplase should be given to patients with suspected massive PE.

  15. Most Massive Globular Cluster in Our Galaxy

    NASA Astrophysics Data System (ADS)

    1994-05-01

    Far down in the southern sky, in the constellation of Centaurus, a diffuse spot of light can be perceived with the unaided eye. It may be unimpressive, but when seen through a telescope, it turns out to be a beautiful, dense cluster of innumerable stars [1]. Omega Centauri, as this object is called, is the brightest of its type in the sky. We refer to it as a "globular cluster", due to its symmetric form. It belongs to our Milky Way galaxy and astrophysical investigations have shown that it is located at a distance of about 16,500 light-years (1 light-year = 9,460,000,000,000 km). Nobody knows for sure how many individual stars it contains, but recent estimates run into the millions. Most of these stars are more than 10,000 million years old and it is generally agreed that Omega Centauri has a similar age. Measurements of its motion indicate that Omega Centauri plows through the Milky Way in an elongated orbit. It is not easy to understand how it has managed to keep its stars together during such an extended period. MEASURING STELLAR VELOCITIES IN OMEGA CENTAURI A group of astronomers [2] have recently carried through a major investigation of Omega Centauri. After many nights of observations at the ESO La Silla observatory, they now conclude that not only is this globular cluster the brightest, it is indeed by far the most massive known in the Milky Way. The very time-consuming observations were made during numerous observing sessions over a period of no less than 13 years (1981-1993), with the photoelectric spectrometer CORAVEL mounted on the 1.5-m Danish telescope at La Silla. The CORAVEL instrument (COrelation RAdial VELocities) was built in a joint effort between the Geneva (Switzerland) and Marseilles (France) observatories. It functions according to the cross-correlation technique, by means of which the spectrum of the observed star is compared with a "standard stellar spectrum" [3]. HOW HEAVY IS OMEGA CENTAURI? In the present study, a total of 1701

  16. Finding Massive Sulfides at Mid-Ocean Ridges

    NASA Astrophysics Data System (ADS)

    Barckhausen, Udo; Dressel, Ingo; Ehrhardt, Axel; Heyde, Ingo; Schwarz-Schampera, Ulrich; Schreckenberger, Bernd; Schwalenberg, Katrin

    2017-04-01

    The formation of Polymetallic Massive Sulfides is connected to hydrothermal activity concentrated in small areas close to mid-ocean ridges. Other geological settings of hydrothermal activity exist of course (like backarcs), but these are typically not located in The Area and therefore not under the regime of the International Seabed Authority (ISA). The ISA grants license areas for mineral exploration of up to 100 blocks of 10 km x 10 km size. The areas in which Polymetallic Massive Sulfides are exposed on the seafloor are tiny compared to the size of the license areas (typically in the order of 100-200m in diameter), and until recently were in most cases detected only be chance. For localizing and investigating Polymetallic Massive Sulfide deposits, geophysical methods are used at a wide range of scales. Ship-mounted overview surveys include multibeam bathymetry, magnetic and gravity measurements and are supplemented with high density sea surface investigations, and deep tow surveys close to the seafloor. Once a Massive Sulfide deposit has been surmised, ROV based video observations and measurements directly at the seafloor are used to confirm the deposit. It turns out that hydrothermal vent sites ("Black Smokers") near mid-ocean ridges are far more common than previously thought, however, due to their small size and location in rugged terrain in the deep sea they are not easy to find. Even though we have no full understanding yet of the geologic and tectonic settings in which long lasting hydrothermal systems can develop, the hydrothermal vent fields known so far seem to have some characteristics in common which can be used to define promising areas on the basis of the bathymetric overview maps. At a dense line spacing of 2.5 km, distinct magnetic anomalies can be observed in surface towed data which are connected to known hydrothermal vent fields. This means that similar magnetic anomalies observed in other places are potential sites of recent or former

  17. VLA 7-mm Observations of Massive Star-forming Regions

    NASA Astrophysics Data System (ADS)

    Linz, Hendrik; Hofner, Peter; Araya, Esteban; Stecklum, Bringfried

    2003-07-01

    The early stages during the formation of massive stars are deeply enshrouded due to the presence of dense and dusty natal material. This prevents observations in the optical and often also in the near-infrared. The emission of the star-forming regions peaks in the far-infrared and sub-mm regime, but at these wavelengths, single-dish observations are restricted in spatial resolution and can give only upper limits on the energetics of the objects of interest. Interferometry at mm wavelengths is one appropriate technique to overcome these limitations. We have started an extensive programme to observe pre-selected massive star-forming regions. Our tool is the VLA and its 7-mm receiver system. The VLA can be operated in several antenna configurations delivering resolutions from 1.5 arcsec down to 0.05 arcsec, which is superior to other current mm-interferometers. Sub-arcsec resolution is strongly needed to disentangle the often crowded regions of high-mass star formation and to clearly separate our objects of interest from the adjacent ultracompact HII regions. At 7 mm we are on the save ground of the Rayleigh-Jeans limit even for emission of cold dust (a fact that is not always true for observations at smaller wavelengths). Almost all circumstellar density configurations are optically thin at 7 mm, thus, the observations will trace the total dust content. However, at 7 mm also the free-free emission from ionised gas (caused by the UV emission of the young massive stars) can contribute to the observed signal. Therefore, we have to identify and remove these "parasitic" constituents by extrapolating interferometric data obtained at cm-wavelengths. The targets are either taken from the list of Molinari (Molinari et al. 2000, A&A, 355, 617) or are well-known massive star-forming complexes, for which we have already acquired additional data at other wavelengths. We have started with observations at lower and medium resolution (1.5 - 0.5 arcsec) to distinguish candidates for

  18. Formation and evolution of hypernova progenitors in massive binary systems

    NASA Astrophysics Data System (ADS)

    Becker, John Alex

    2004-10-01

    The massive stellar progenitor of a hypernova explosion and an associated gamma-ray burst must satisfy two primary constraints: (1)the outer layers of the stellar core must possess sufficient angular momentum to form a centrifugally supported torus about the collapsed central object (a Kerr black hole); and, (2)the envelope of the star must not be excessively massive or distended, so that the energetic, ultrarelativistic outflow generated by the central engine in the core of the star does not risk being smothered before it can escape from the star and expand outward to produce a gamma-ray burst. We have developed a new one-dimensional stellar evolution code that includes the effects of rotation on equilibrium stellar structure, and calculates the transport of angular momentum through the stellar interior due to convection, dynamical and secular shear instabilities, and gravity (buoyancy) waves. We have used this code to calculate a variety of evolutionary sequences involving the transfer of mass from one component of the binary system to the other. We have also calculated an evolutionary sequence ending in the merger of one component of the system with the core of the other, induced by a prior common-envelope phase. We find that over a wide range of initial binary system parameters, the initially less massive component of the system can accrete a substantial amount of mass and angular momentum from the initially more massive component. The accreted angular momentum is efficiently transported inward from the surface of the accreting star toward its core by a combination of convection and dynamical and secular shear instabilities. If accretion commences while the accretor is still on the main sequence, we find that the inward-progressing wave of angular momentum can penetrate the core of the mass- gaining star, contributing to its store of rotational angular momentum without the need for gravity wave transport of angular momentum across the core-envelope interface

  19. 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.

  20. Propagation peculiarities of mean field massive gravity

    DOE PAGES

    Deser, S.; Waldron, A.; Zahariade, G.

    2015-07-28

    Massive gravity (mGR) describes a dynamical “metric” on a fiducial, background one. We investigate fluctuations of the dynamics about mGR solutions, that is about its “mean field theory”. Analyzing mean field massive gravity (m¯GR) propagation characteristics is not only equivalent to studying those of the full non-linear theory, but also in direct correspondence with earlier analyses of charged higher spin systems, the oldest example being the charged, massive spin 3/2 Rarita–Schwinger (RS) theory. The fiducial and mGR mean field background metrics in the m¯GR model correspond to the RS Minkowski metric and external EM field. The common implications in bothmore » systems are that hyperbolicity holds only in a weak background-mean-field limit, immediately ruling both theories out as fundamental theories; a situation in stark contrast with general relativity (GR) which is at least a consistent classical theory. Moreover, even though both m¯GR and RS theories can still in principle be considered as predictive effective models in the weak regime, their lower helicities then exhibit superluminal behavior: lower helicity gravitons are superluminal as compared to photons propagating on either the fiducial or background metric. Thus our approach has uncovered a novel, dispersive, “crystal-like” phenomenon of differing helicities having differing propagation speeds. As a result, this applies both to m¯GR and mGR, and is a peculiar feature that is also problematic for consistent coupling to matter.« less

  1. Molecular Outflows from Newly Formed Massive Stars

    NASA Astrophysics Data System (ADS)

    Kim, Kee-Tae; Kim, Won-Ju; Kim, Chang-Hee

    2015-12-01

    We map 6 massive young stellar objects (YSOs) in the CO J=2-1 line and survey 18 massive YSOs, including the six, in the hcopj, sioj, water 6_{16}-5_{23} maser, and methanol 7_{0}-6_{1} A^{+} maser lines. We detect CO bipolar outflows in all the six mapped sources. Four of them are newly discovered (ifive, ieight, inine, iten), while itwo is mapped in the CO J=2-1 line for the first time. The detected outflows are much more massive and energetic than outflows from low-mass YSOs with masses >20 M_⊙ and momenta >300 M_⊙ km/s. They have mass outflow rates (3-6)×10^{-4} M_⊙ yr^{-1}, which are at least one order of magnitude greater than those observed in low-mass YSOs. We detect hcop and SiO line emission in 18 (100%) and 4 (22%) sources, respectively. The hcop spectra show high-velocity wings in 11 (61%) sources. We detect water maser emission in 13 (72%) sources and 44 GHz methanol maser emission in 8 (44%) sources. Of the detected sources, 5 water and 6 methanol maser sources are new discoveries. iseven shows high-velocity (>30 kms) water maser lines. We find good correlations of the bolometric luminosity of the central (proto)star with the mechanical force, mechanical luminosity, and mass outflow rate of molecular outflow %L_{bol} with F_{m}, L_{m}, and dot{M}_{out} in the bolometric luminosity range of 10^{-1}-10^6 lsol, and identified 3 intermediate- or high-mass counterparts of Class O objects.

  2. 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

  3. AIMS: Asteroseismic Inference on a Massive Scale

    NASA Astrophysics Data System (ADS)

    Reese, Daniel R.

    2016-11-01

    AIMS (Asteroseismic Inference on a Massive Scale) estimates stellar parameters and credible intervals/error bars in a Bayesian manner from a set of seismic frequency data and so-called classic constraints. To achieve reliable parameter estimates and computational efficiency it searches through a grid of pre-computed models using an MCMC algorithm; interpolation within the grid of models is performed by first tessellating the grid using a Delaunay triangulation and then doing a linear barycentric interpolation on matching simplexes. Inputs for the modeling consists of individual frequencies from peak-bagging, which can be complemented with classic spectroscopic constraints.

  4. Associative Networks on a Massively Parallel Computer.

    DTIC Science & Technology

    1985-10-01

    Q I; 11"_ QL 11111 --.25 111.4 111 3 .6 11. MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS-1963-A .9 "* ’ - - . S % .’- . ’’ ." ".d...8217 14. TITLE (end Subtitle) L TYPE OF REPORT A PERIOD COVERED Associative Networks on a Massively Parallel Technical paper Computer S . PERFORMING OG...REPORT NUMBER . AUTHOR( s ) 4. CONTRACT OR GRANT NUMBER(&) Gary Jackoway AFOSR-83-0205 . PERFORMING ORGANIZATION NAME AND ADDRESS 0. PROGRAM ENT. PROJECT

  5. New Cosmological Solutions in Massive Gravity Theory

    NASA Astrophysics Data System (ADS)

    Pinho, S. S. A.; Pereira, S. H.; Mendonça, E. L.

    2017-04-01

    In this paper we present some new cosmological solutions in massive gravity theory. Some homogeneous and isotropic solutions correctly describe accelerated evolutions for the universe. The study was realized considering a specific form to the fiducial metric and found different functions and constant parameters of the theory that guarantee the conservation of the energy momentum tensor. Several accelerating cosmologies were found, all of them reproducing a cosmological constant term proportional to the graviton mass, with a de Sitter type solution for the scale factor. We have also verified that when the fiducial metric is close to the physical metric the solutions are absent, except for some specific open cases.

  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. 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.

  8. Pattern recognition and massively distributed computing.

    PubMed

    Davies, E Keith; Glick, Meir; Harrison, Karl N; Richards, W Graham

    2002-12-01

    A feature of Peter Kollman's research was his exploitation of the latest computational techniques to devise novel applications of the free energy perturbation method. He would certainly have seized upon the opportunities offered by massively distributed computing. Here we describe the use of over a million personal computers to perform virtual screening of 3.5 billion druglike molecules against protein targets by pharmacophore pattern matching, together with other applications of pattern recognition such as docking ligands without any a priori knowledge about the binding site location.

  9. 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.

  10. Massive symmetric tensor field in curved spacetime

    NASA Astrophysics Data System (ADS)

    Higuchi, Atsushi

    1989-03-01

    The condition on the background spacetime is derived for the straightforward generalization of the massive symmetric tensor field (MSTF) equation to be possible. The MSTF in spatially flat Robertson-Walker spacetimes is studied in detail. The abovementioned condition in these spacetimes is verified by calculating the Klein-Gordon inner products among the solutions of the field equation. It is shown that the MSTF theory in some spacetimes has features which are probably undesirable even if the condition on the spacetime is satisfied.

  11. 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

  12. 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.

  13. 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

  14. Axionlike particle assisted strongly interacting massive particle

    NASA Astrophysics Data System (ADS)

    Kamada, Ayuki; Kim, Hyungjin; Sekiguchi, Toyokazu

    2017-07-01

    We propose a new realization of strongly interacting massive particles (SIMPs) as self-interacting dark matter, where SIMPs couple to the standard model (SM) sector through an axionlike particle. Our model overcomes major obstacles accompanying the original SIMP model, such as a missing mechanism of kinetically equilibrating SIMPs with the SM plasma as well as marginal perturbativity of the chiral Lagrangian density. Remarkably, the parameter region realizing σself/mDM≃0.1 - 1 cm2/g is within the reach of future beam dump experiments such as the Search for Hidden Particles experiment.

  15. 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.

  16. Hamiltonian analysis of BHT massive gravity

    NASA Astrophysics Data System (ADS)

    Blagojević, M.; Cvetković, B.

    2011-01-01

    We study the Hamiltonian structure of the Bergshoeff-Hohm-Townsend (BHT) massive gravity with a cosmological constant. In the space of coupling constants ( Λ 0, m 2), our canonical analysis reveals the special role of the condition Λ 0/ m 2 ≠ -1. In this sector, the dimension of the physical phase space is found to be N ∗ = 4, which corresponds to two Lagrangian degree of freedom. When applied to the AdS asymptotic region, the canonical approach yields the conserved charges of the BTZ black hole, and central charges of the asymptotic symmetry algebra.

  17. Massive phytoplankton blooms under Arctic sea ice.

    PubMed

    Arrigo, Kevin R; Perovich, Donald K; Pickart, Robert S; Brown, Zachary W; van Dijken, Gert L; Lowry, Kate E; Mills, Matthew M; Palmer, Molly A; Balch, William M; Bahr, Frank; Bates, Nicholas R; Benitez-Nelson, Claudia; Bowler, Bruce; Brownlee, Emily; Ehn, Jens K; Frey, Karen E; Garley, Rebecca; Laney, Samuel R; Lubelczyk, Laura; Mathis, Jeremy; Matsuoka, Atsushi; Mitchell, B Greg; Moore, G W K; Ortega-Retuerta, Eva; Pal, Sharmila; Polashenski, Chris M; Reynolds, Rick A; Schieber, Brian; Sosik, Heidi M; Stephens, Michael; Swift, James H

    2012-06-15

    Phytoplankton blooms over Arctic Ocean continental shelves are thought to be restricted to waters free of sea ice. Here, we document a massive phytoplankton bloom beneath fully consolidated pack ice far from the ice edge in the Chukchi Sea, where light transmission has increased in recent decades because of thinning ice cover and proliferation of melt ponds. The bloom was characterized by high diatom biomass and rates of growth and primary production. Evidence suggests that under-ice phytoplankton blooms may be more widespread over nutrient-rich Arctic continental shelves and that satellite-based estimates of annual primary production in these waters may be underestimated by up to 10-fold.

  18. Massive acquired cholesteatoma of the temporal bone.

    PubMed

    Wright, J L; Colman, B H; Connor, A F

    1976-03-01

    Nine patients with massive acquired cholesteatoma of the temporal bone were treated by radical mastoidectomy, facial nerve decompression, and excision of the inner ear. The commonest presenting symptoms were otorrhea and deafness, but otalgia, vertigo, external swelling and facial nerve palsies were also seen. Polytomography was helpful in assessing the degree of bone erosion preoperatively. The large cavity present following cholesteatoma excision was partially obliterated by a superiorly based temporalis muscle pedicle which helped to seal the internal auditory meatus and prevented the development of a cerebral hernia. Those patients with preoperative facial nerve palsies showed evidence of nerve degeneration and had incomplete recovery at a one year follow-up.

  19. Holographic renormalization of new massive gravity

    SciTech Connect

    Alishahiha, Mohsen; Naseh, Ali

    2010-11-15

    We study holographic renormalization for three-dimensional new massive gravity. By studying the general falloff conditions for the metric allowed by the model at infinity, we show that at the critical point where the central charges of the dual conformal field theory (CFT) are zero, it contains a leading logarithmic behavior. In the context of AdS/CFT correspondence it can be identified as a source for an irrelevant operator in the dual CFT. The presence of the logarithmic falloff may be interpreted as the fact that the dual CFT would be a logarithmic conformal field theory.

  20. Drag phenomena from holographic massive gravity

    NASA Astrophysics Data System (ADS)

    Baggioli, Matteo; Brattan, Daniel K.

    2017-01-01

    We consider the motion of point particles in a strongly coupled field theory with broken translation invariance. We obtain the energy and momentum loss rates and drag coefficients for a class of such particles by solving for the motion of classical strings in holographic massive gravity. At low temperatures compared to the graviton mass the behaviour of the string is controlled by the appearance of an exotic ground state with non-zero entropy at zero temperature. Additionally, we find an upper bound on the diffusion constant for a collection of these particles which is saturated when the mass of the graviton goes to zero.

  1. Massively-Parallel Dislocation Dynamics Simulations

    SciTech Connect

    Cai, W; Bulatov, V V; Pierce, T G; Hiratani, M; Rhee, M; Bartelt, M; Tang, M

    2003-06-18

    Prediction of the plastic strength of single crystals based on the collective dynamics of dislocations has been a challenge for computational materials science for a number of years. The difficulty lies in the inability of the existing dislocation dynamics (DD) codes to handle a sufficiently large number of dislocation lines, in order to be statistically representative and to reproduce experimentally observed microstructures. A new massively-parallel DD code is developed that is capable of modeling million-dislocation systems by employing thousands of processors. We discuss the general aspects of this code that make such large scale simulations possible, as well as a few initial simulation results.

  2. Massive hydrothorax following subclavian vein catheterization

    PubMed Central

    2010-01-01

    Since the introduction of central venous catheterization for monitoring of the venous pressure, fluid infusion and hyperalimentation, the literature has been full of serious life-threatening complications. Of these complications is the false positioning of the central venous catheter and subsequent development of pleural effusion. In this report we are describing a case of iatrogenic massive pleural effusion following subclavian vein catheterization necessitating intercostal tube drainage and mechanical ventilation. The case highlights the importance of ensuring adequate positioning of the catheter after insertion through aspiration of venous blood, immediate post insertion X-ray and the utilization of ultrasound guidance in cases with expected difficult catheterization. PMID:21073758

  3. Non-Pauli-Fierz Massive Gravitons

    SciTech Connect

    Dvali, Gia; Pujolas, Oriol; Redi, Michele

    2008-10-24

    We study general Lorentz invariant theories of massive gravitons. We show that, contrary to the standard lore, there exist consistent theories where the graviton mass term violates Pauli-Fierz structure. For theories where the graviton is a resonance, this does not imply the existence of a scalar ghost if the deviation from a Pauli-Fierz structure becomes sufficiently small at high energies. These types of mass terms are required by any consistent realization of the Dvali-Gabadadze-Porrati model in higher dimension.

  4. 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.

  5. UV spectroscopy of the most massive overcontact binary known to date: on the verge of coalescence ?

    NASA Astrophysics Data System (ADS)

    Sana, Hugues

    2014-10-01

    Binary interaction dominates the evolution of massive stars. Because of the abundance of short period systems, about a quarter of all massive stars are thought to merge with their companion. The short-lived contact phase preceding coalescence is poorly understood due to the lack of observational constraints: only two overcontact O-type binaries are known so far. Yet, these systems provide crucial observational testbeds to understand the elusive formation and evolution of the most massive stars, the complex physics of stellar mergers and the role that the coalescence products play as progenitors of supernovae and gamma-ray bursts. We recently discovered VFTS 352, the most massive, earliest spectral type and shortest period (P = 1.12 d) overcontact O-type binary known to date. With an estimated combined mass of 130 Msun, this truly unique system is expected to merge into a rapidly rotating, very massive, single star. Initial estimates of the physical parameters were derived from high-quality ground-based optical spectra and photometry. Yet, optical analyses of overcontact systems can overestimate the radial-velocity amplitudes, hence the masses, by up to 40% because optical lines are susceptible to irradiation effects. Here we propose a limited 8-epochs COS monitoring of VFTS 352. The G130M and G160M spectra will allow us to side step the uncertainties affecting optical determination of the masses and to constrain the mass loss rate and CNO surface abundances. These constraints are crucial to identify the complex mixing processes, to reveal signs of mass exchange and mass loss from the system, and to enable a comparison with massive binary evolution models.

  6. A MASSIVE RUNAWAY STAR FROM 30 DORADUS

    SciTech Connect

    Evans, C. J.; Walborn, N. R.; Massa, D.; Lennon, D. J.; Crowther, P. A.; Henault-Brunet, V.; Taylor, W. D.; Howarth, I. D.; Sana, H.; Van Loon, J. Th.

    2010-06-01

    We present the first ultraviolet (UV) and multi-epoch optical spectroscopy of 30 Dor 016, a massive O2-type star on the periphery of 30 Doradus in the Large Magellanic Cloud. The UV data were obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope as part of the Servicing Mission Observatory Verification program after Servicing Mission 4, and reveal no. 016 to have one of the fastest stellar winds known. From analysis of the C IV {lambda}{lambda}1548-51 doublet we find a terminal velocity, v {sub {infinity}} = 3450 {+-} 50 km s{sup -1}. Optical spectroscopy is from the VLT-FLAMES Tarantula Survey, from which we rule out a massive companion (with 2 days < P < 1 yr) to a confidence of 98%. The radial velocity of no. 016 is offset from the systemic value by -85 km s{sup -1}, suggesting that the star has traveled the 120 pc from the core of 30 Doradus as a runaway, ejected via dynamical interactions.

  7. Massive Ascites and Pleural Effusion in Preeclampsia

    PubMed Central

    Deveer, Ruya; Camuzcuoglu, Aysun; Kasap, Burcu; Camuzcuoglu, Hakan

    2017-01-01

    Preeclampsia is defined as new onset hypertension and proteinuria after 20 weeks of gestation and complicates approximately 2-8% of all pregnancies. Release of vasoconstrictive agents, endothelial damage, hyperpermeability of the capillaries and microangiopathic haemolysis involves the basic pathophysiology. It has variable clinical presentation. Here, we report a case of severe preeclampsia who developed postpartum massive ascites and pleural effusion. Primigravid patient was admitted to our clinic at 35 weeks of gestation with very high blood pressure. In biochemical analysis, Alanine aminotransferase (ALT) was 401 U/L, Aspartate aminotransferase (AST) was 292 U/L. An emergency caesarean section was performed because of fetal distress. On the 2nd post-operative day, abdominal distension and severe abdominal pain occurred. On the 3rd post-operative day, her abdominal distension increased and Ultrasonography (USG) revealed massive ascites. Abdominal drainage was performed and albumin infusion was administered. On postoperative day 4, she still had abdominal distension and concomitant respiratory distress. Computed Tomography (CT) showed ascites and bilateral pleural effusion. Her complaint regressed on the following days.

  8. 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.

  9. 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.

  10. 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.

  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. 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.

  13. 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.

  14. 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.

  15. Massive rotator cuff tears: definition and treatment.

    PubMed

    Lädermann, Alexandre; Denard, Patrick J; Collin, Philippe

    2015-12-01

    The aim of this review is to summarise tear pattern classification and management options for massive rotator cuff tears (MRCT), as well as to propose a treatment paradigm for patients with a MRCT. Data from 70 significant papers were reviewed in order to define the character of reparability and the possibility of alternative techniques in the management of MRCT. Massive rotator cuff tears (MRCT) include a wide panoply of lesions in terms of tear pattern, functional impairment, and reparability. Pre-operative evaluation is critical to successful treatment. With the advancement of medical technology, arthroscopy has become a frequently used method of treatment, even in cases of pseudoparalytic shoulders. Tendon transfer is limited to young patients with an irreparable MRCT and loss of active rotation. Arthroplasty can be considered for the treatment of a MRCT with associated arthritis. There is insufficient evidence to establish an evidence-based treatment algorithm for MRCTs. Treatment is based on patient factors and associated pathology, and includes personal experience and data from case series.

  16. A massive lesion detection algorithm in mammography.

    PubMed

    Fauci, Francesco; Raso, Giuseppe; Magro, Rosario; Forni, Giustina; Lauria, Adele; Bagnasco, Stefano; Cerello, Piergiorgio; Cheran, Sorin C; Lopez Torres, Ernesto; Bellotti, Robero; Carlo, Francesco De; Gargano, Gianfranco; Tangaro, Sonia; Mitri, Ivan De; Nunzio, Giorgio De; Cataldo, Rossella

    A new algorithm for massive lesion detection in mammography is presented. The algorithm consists in three main steps: 1) reduction of the dimension of the image to be processed through the identification of regions of interest (roi) as candidates for massive lesions; 2) characterization of the RoI by means of suitable feature extraction; 3) pattern classification through supervised neural networks. Suspect regions are detected by searching for local maxima of the pixel grey level intensity. A ring of increasing radius, centered on a maximum, is considered until the mean intensity in the ring decreases to a defined fraction of the maximum. The ROIS thus obtained are described by average, variance, skewness and kurtosis of the intensity distributions at different fractions of the radius. A neural network approach is adopted to classify suspect pathological and healthy pattern. The software has been designed in the framework of the INFN (Istituto Nazionale Fisica Nucleare) research project GPCALMA (Grid Platform for Calma) which recruits physicists and radiologists from different Italian Research Institutions and hospitals to develop software for breast cancer detection.

  17. 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.

  18. Linear Time Vertex Partitioning on Massive Graphs.

    PubMed

    Mell, Peter; Harang, Richard; Gueye, Assane

    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.

  19. 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.

  20. Massive naproxen overdose with serial serum levels.

    PubMed

    Al-Abri, Suad A; Anderson, Ilene B; Pedram, Fatehi; Colby, Jennifer M; Olson, Kent R

    2015-03-01

    Massive naproxen overdose is not commonly reported. Severe metabolic acidosis and seizure have been described, but the use of renal replacement therapy has not been studied in the context of overdose. A 28-year-old man ingested 70 g of naproxen along with an unknown amount of alcohol in a suicidal attempt. On examination in the emergency department 90 min later, he was drowsy but had normal vital signs apart from sinus tachycardia. Serum naproxen level 90 min after ingestion was 1,580 mg/L (therapeutic range 25-75 mg/L). He developed metabolic acidosis requiring renal replacement therapy using sustained low efficiency dialysis (SLED) and continuous venovenous hemofiltration (CVVH) and had recurrent seizure activity requiring intubation within 4 h from ingestion. He recovered after 48 h. Massive naproxen overdose can present with serious toxicity including seizures, altered mental status, and metabolic acidosis. Hemodialysis and renal replacement therapy may correct the acid base disturbance and provide support in cases of renal impairment in context of naproxen overdose, but further studies are needed to determine the extraction of naproxen.

  1. Massive Contingency Analysis with High Performance Computing

    SciTech Connect

    Huang, Zhenyu; Chen, Yousu; Nieplocha, Jaroslaw

    2009-07-26

    Contingency analysis is a key function in the Energy Management System (EMS) to assess the impact of various combinations of power system component failures based on state estimates. Contingency analysis is also extensively used in power market operation for feasibility test of market solutions. Faster analysis of more cases is required to safely and reliably operate today’s power grids with less marginal and more intermittent renewable energy sources. Enabled by the latest development in the computer industry, high performance computing holds the promise of meet the need in the power industry. This paper investigates the potential of high performance computing for massive contingency analysis. The framework of "N-x" contingency analysis is established and computational load balancing schemes are studied and implemented with high performance computers. Case studies of massive 300,000-contingency-case analysis using the Western Electricity Coordinating Council power grid model are presented to illustrate the application of high performance computing and demonstrate the performance of the framework and computational load balancing schemes.

  2. 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.

  3. 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

  4. 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.

  5. Constraints on shear and rotation with massive galaxy clusters

    NASA Astrophysics Data System (ADS)

    Mehrabi, Ahmad; Pace, Francesco; Malekjani, Mohammad; Del Popolo, Antonino

    2017-03-01

    A precise determination of the mass function is an important tool to verify cosmological predictions of the Λ cold dark matter (CDM) model and to infer more precisely the better model describing the evolution of the Universe. Galaxy clusters have been currently used to infer cosmological parameters, in particular the matter density parameter Ωm, the matter power spectrum normalization σ8 and the equation of state parameter wde of the dark energy fluid. In this work, using data on massive galaxy clusters (M > 8 × 1014 h-1 M⊙) in the redshift range 0.05 ≲ z ≲ 0.83, for the first time we put constraints on the parameter α introduced within the formalism of the extended spherical collapse model to quantify deviations from sphericity due to shear and rotation. Since at the moment there is no physical model describing its functional shape, we assume it to be a logarithmic function of the cluster mass. By holding σ8 fixed and restricting our analysis to a ΛCDM model, we find, at 1σ confidence level, Ωm = 0.284 ± 0.0064, h = 0.678 ± 0.017 and β =0.0019^{+0.0008}_{-0.0015}, where β represents the slope of the parameter α. This result translates into a 9 per cent decrement of the number of massive clusters with respect to a standard ΛCDM mass function, but better data are required to better constrain this quantity, since at the 2σ and 3σ confidence level we are only able to infer upper limits.

  6. 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.

  7. Young and turbulent: the early life of massive galaxy progenitors

    NASA Astrophysics Data System (ADS)

    Fiacconi, Davide; Mayer, Lucio; Madau, Piero; Lupi, Alessandro; Dotti, Massimo; Haardt, Francesco

    2017-06-01

    We present results from the 'Ponos' simulation suite on the early evolution of a massive, Mvir(z = 0) = 1.2 × 1013 M⊙ galaxy. At z ≳ 6, before feedback from a central supermassive black hole becomes dominant, the main galaxy has a stellar mass ˜2 × 109 M⊙ and a star formation rate ˜20 M⊙ yr-1. The galaxy sits near the expected main sequence of star-forming galaxies at those redshifts, and resembles moderately star-forming systems observed at z > 5. The high specific star formation rate results in vigorous heating and stirring of the gas by supernovae feedback, and the galaxy develops a thick and turbulent disc, with gas velocity dispersion ˜40 km s-1, rotation to dispersion ratio ˜2, and with a significant amount of gas at ˜105 K. The Toomre parameter always exceeds the critical value for gravito-turbulence, Q ˜ 1.5-2, mainly due to the contribution of warm/hot gas inside the disc. Without feedback, a nearly gravito-turbulent regime establishes with similar gas velocity dispersion and lower Q. We propose that the 'hot and turbulent' disc regime seen in our simulations, unlike the 'cold and turbulent' gravito-turbulent regime of massive clumpy disc galaxies at z ˜ 1-2, is a fundamental characterization of the main-sequence galaxies at z ≳ 6, as they can sustain star formation rates comparable to those of low-mass starbursts at z = 0. This results in no sustained coherent gas inflows through the disc, and in fluctuating and anisotropic mass transport, possibly postponing the assembly of the bulge and causing the initial feeding of the central black hole to be highly intermittent.

  8. Exoplanet recycling in massive white-dwarf debris discs

    NASA Astrophysics Data System (ADS)

    Van Lieshout, Rik

    2017-06-01

    When a star evolves into a white dwarf, the planetary system it hosts can become unstable. Planets in such systems may then be scattered onto star-grazing orbits, leading to their tidal disruption as they pass within the white dwarf’s Roche limit. We study the massive, compact debris discs that may arrise from this process using a combination of analytical estimates and numerical modelling. The discs are gravitationally unstable, resulting in an enhanced effective viscosity due to angular momentum transport associated with self-gravity wakes. For disc masses greater than ~1026 g (corresponding to progenitor objects comparable to the Galilean moons), viscous spreading dominates over Poynting-Robertson drag in the outer parts of the disc. In such massive discs, mass is transported both in- and outwards. When the outward-flowing material spreads beyond the Roche limit, it coagulates into new (minor) planets in a process analogous to the ongoing formation of Saturn’s innermost moonlets. This process recycles a substantial fraction of the original disc mass (tens of percents), with the bulk of the mass locked in a single large body orbitting in a 2:1 mean-motion resonance with the Roche limit. As such, the recycling of a tidally disrupted super-Earth could yield an Earth-mass planet on a 10--20 hr orbit. For white dwarfs with a temperature below 6000-7000 K (corresponding to a cooling age of >1--2 Gyr), this orbit is located in the white dwarf’s habitable zone. The recycling process also creates a string of smaller bodies just outside the Roche limit. These may account for the collection of minor planets postulated to orbit white dwarf WD 1145+017.

  9. 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.

  10. 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.

  11. Neutron stars structure in the context of massive gravity

    NASA Astrophysics Data System (ADS)

    Hendi, S. H.; Bordbar, G. H.; Eslam Panah, B.; Panahiyan, S.

    2017-07-01

    Motivated by the recent interests in spin-2 massive gravitons, we study the structure of neutron star in the context of massive gravity. The modifications of TOV equation in the presence of massive gravity are explored in 4 and higher dimensions. Next, by considering the modern equation of state for the neutron star matter (which is extracted by the lowest order constrained variational (LOCV) method with the AV18 potential), different physical properties of the neutron star (such as Le Chatelier's principle, stability and energy conditions) are investigated. It is shown that consideration of the massive gravity has specific contributions into the structure of neutron star and introduces new prescriptions for the massive astrophysical objects. The mass-radius relation is examined and the effects of massive gravity on the Schwarzschild radius, average density, compactness, gravitational redshift and dynamical stability are studied. Finally, a relation between mass and radius of neutron star versus the Planck mass is extracted.

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

    PubMed

    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.

  13. Clinical diagnosis of massive hemoptysis using the fiberoptic bronchoscope.

    PubMed

    Imgrund, S P; Goldberg, S K; Walkenstein, M D; Fischer, R; Lippmann, M L

    1985-05-01

    Pulmonary resection, when possible, is the conventional treatment of massive hemoptysis. Alternatives include bronchial artery embolization, Fogarty catheter balloon tamponade, and pharmacologic approaches. We used endotracheal intubation and flexible bronchoscopy to locate the bleeding site in three of four patients with massive hemoptysis. These cases are used to review the etiology of massive hemoptysis and the usefulness of flexible bronchoscopy to localize the source of hemorrhage.

  14. 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.

  15. Fundamental Parameters of Four Massive Eclipsing Binaries in Westerlund 1

    NASA Astrophysics Data System (ADS)

    Koumpia, E.; Bonanos, A. Z.

    2012-04-01

    We present fundamental parameters of four 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.

  16. Fundamental Parameters of Four Massive Eclipsing Binaries in Westerlund 1

    NASA Astrophysics Data System (ADS)

    Bonanos, A.; Koumpia, E.

    2012-01-01

    We present fundamental parameters of four 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.

  17. Study of Stellar Clusters Containing Massive Stars

    NASA Astrophysics Data System (ADS)

    Costado, Teresa; Alfaro, E. J.; Delgado, A. J.; Djupvik, A. A.; Maíz Apellániz, J.

    2013-06-01

    Most stars form in clusters, but the percentage of stars born in dense stellar systems is currently matter of controversy and depends very much on the own definition of cluster. The cluster definition and hence the morphologies of individual clusters appear to vary significantly from region to region, as well as with age, which suggests that either, star formation in clusters is not universal and may depend on the local environment, or that all clusters form with the same morphology but early dynamical evolution quickly modifies the structure of the phase space distribution. In addition, young populated clusters containing massive stars are excellent labs for the study of the formation of the massive stellar component of the Galactic disk. Three main scenarios have been proposed for the formation of high-mass stars (M > 7-8 M_{⊙}): a) monolithic collapse of proto-stellar nuclei; b) competitive accretion inside the proto-cluster molecular cloud; and c) coalescence of proto-stellar nuclei and low-mass stars in very dense atmospheres. Both scientific questions: a) cluster formation and b) formation of high mass stars in clusters are intimately connected via the structural description of the phase space distribution of cluster stars and their Mass Function (MF). Models of static clusters with different initial spatial and kinematic distributions show how the spatial distribution dynamically evolves with time, allowing a characterization of their dynamical state from snapshots of their spatial distribution. Four are the main variables (and their distribution with mass and position) needed for a reliable characterization of the cluster dynamical state: a) Mass segregation parameter; b) Mapping of surface density for different ranges of masses; c) Q morphological parameter based on the minimum spanning tree graph and its variation with mass and cluster age, and d) MF of the cluster members. Two years ago, the Stellar System Group of IAA has begun an observational

  18. Exact solutions in 3D new massive gravity.

    PubMed

    Ahmedov, Haji; Aliev, Alikram N

    2011-01-14

    We show that the field equations of new massive gravity (NMG) consist of a massive (tensorial) Klein-Gordon-type equation with a curvature-squared source term and a constraint equation. We also show that, for algebraic type D and N spacetimes, the field equations of topologically massive gravity (TMG) can be thought of as the "square root" of the massive Klein-Gordon-type equation. Using this fact, we establish a simple framework for mapping all types D and N solutions of TMG into NMG. Finally, we present new examples of types D and N solutions to NMG.

  19. Formation of young massive clusters from turbulent molecular clouds

    NASA Astrophysics Data System (ADS)

    Fujii, Michiko S.

    2015-08-01

    Young massive clusters are as young as open clusters but more massive and compact compared with typical open clusters. The formation process of young massive clusters is still unclear, and it is an open question whether the formation process is the same for typical open clusters or not. We perform a series of N-body simulations starting from initial conditions constructed from the results of hydrodynamical simulations of turbulent molecular clouds. In our simulations, both open clusters and young massive clusters form when we assume a density-dependent star-formation efficiency. We find that a local star-formation efficiency higher than 50% is necessary for the formation of young massive clusters, but open clusters form from less dense regions with a local star formation efficiency of < 50%. We confirm that the young massive clusters formed in our simulations have mass, size, and density profile similar to those of observed young massive clusters such as NGC 3603 and Trumpler 14. We also find that these simulated clusters evolve via hierarchical mergers of sub-clusters within a few mega years, as is suggested by recent simulations and observations. Although we do not assume initial mass segregation, we observe that the simulated massive clusters show a shallower slope of the mass function (Γ ˜ -1) in the cluster center compared to that of the entire cluster (Γ ˜ -1.3). These values are consistent with those of some young massive clusters in the Milky Way such as Westerlund 1 and Arches.

  20. Exact Solutions in 3D New Massive Gravity

    SciTech Connect

    Ahmedov, Haji; Aliev, Alikram N.

    2011-01-14

    We show that the field equations of new massive gravity (NMG) consist of a massive (tensorial) Klein-Gordon-type equation with a curvature-squared source term and a constraint equation. We also show that, for algebraic type D and N spacetimes, the field equations of topologically massive gravity (TMG) can be thought of as the 'square root' of the massive Klein-Gordon-type equation. Using this fact, we establish a simple framework for mapping all types D and N solutions of TMG into NMG. Finally, we present new examples of types D and N solutions to NMG.

  1. Exact Solutions in 3D New Massive Gravity

    NASA Astrophysics Data System (ADS)

    Ahmedov, Haji; Aliev, Alikram N.

    2011-01-01

    We show that the field equations of new massive gravity (NMG) consist of a massive (tensorial) Klein-Gordon-type equation with a curvature-squared source term and a constraint equation. We also show that, for algebraic type D and N spacetimes, the field equations of topologically massive gravity (TMG) can be thought of as the “square root” of the massive Klein-Gordon-type equation. Using this fact, we establish a simple framework for mapping all types D and N solutions of TMG into NMG. Finally, we present new examples of types D and N solutions to NMG.

  2. Massive intestinal infarction in young women: complication of use of oral contraceptives?

    PubMed Central

    Koh, K. S.; Danzinger, R. G.

    1977-01-01

    Massive intestinal infarction due to occlusion of the celiac, superior mesenteric and inferior mesenteric arteries occurred in two young women, one of who subsequently died. Both were smokers. They had ingested oral contraceptives for 5 and 8 years, respectively, but this therapy could not be proven to be a causative factor in their ischemic bowel disease; although such an association is uncommon, it should be considered in young women with abdominal pain. Images FIG. 1 PMID:837318

  3. Idiopathic massive myocardial calcification: a case report and review of the literature.

    PubMed

    Shackley, Brit S; Nguyen, Thao P; Shivkumar, Kalyanam; Finn, Paul J; Fishbein, Michael C

    2011-01-01

    We report a rare case of massive myocardial calcification in a 42-year-old male who presented with symptoms of congestive heart failure and arrhythmia. Myocardial calcification is most commonly associated with myocardial infarction or, less commonly, hypercalcemia. This case is particularly unusual due to the lack of any known predisposing risk factors, including normal coronary arteries, normal renal function, and normal serum calcium levels. Alternative etiologies are discussed accompanied by a review of the literature.

  4. An Autopsy Case of Acute Massive Hematochezia Caused by Superior Mesenteric Vein Thrombosis: A First Report in Forensic Medicine.

    PubMed

    Watanabe, Mayumi; Unuma, Kana; Makino, Yohsuke; Noritake, Kanako; Yamada, Atsushi; Iwase, Hirotaro; Uemura, Koichi

    2016-01-01

    Superior mesenteric vein thrombosis (SMVT) is an uncommon cause of intestinal ischemia and massive gastrointestinal bleeding. This report describes a man with alcoholic liver cirrhosis, who died of massive hematochezia due to SMVT. A medicolegal autopsy disclosed a thrombus at the superior mesenteric vein and hemorrhagic infarction of the bowel wall, an area also within the territory of the superior mesenteric vein. Liver cirrhosis, an enlarged spleen, and esophageal varices without rupture were also observed, but ulcers and variceal bleeding were not. Other organs showed no significant findings. His blood alcohol level was 0.14% w/v. Thus, this man died from severe hematochezia associated with SMVT due to liver cirrhosis and alcohol dehydration, which can lead to coagulopathy and rapid progress of thrombus formation. This is the first report on an alternate cause for massive gastrointestinal hemorrhage with a cirrhotic patient in a forensic autopsy. © 2015 American Academy of Forensic Sciences.

  5. Ventilation-induced massive lethal air embolism and subcutaneous emphysema in a patient with a lung cavern.

    PubMed

    Verelst, Wim; Verbrugghe, Walter; Lammens, Martin; Snoeckx, Annemie; Jorens, Philippe G

    2015-01-01

    The simultaneous occurrence of subcutaneous emphysema and intravascular air due to an air embolism is a rare condition. Here, we report a patient with COPD who developed a severe episode of hemoptysis due to rupture of a previously undiagnosed lung cavern. Intubation and ventilation led to the development of both massive subcutaneous emphysema and a massive air embolism, resulting from aspiration of air through a torn pulmonary vessel in the cavern. The dramatic amount of intravenous air and subsequent conduction along the venous system to the right heart and pulmonary trunk caused major hemodynamic compromise and ultimately death. The degree of subcutaneous emphysema, especially the massive venous air embolism, was unprecedented. Copyright © 2015 by Daedalus Enterprises.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Two-Loop QCD correction to massive spin-2 resonance → 3 gluons

    NASA Astrophysics Data System (ADS)

    Ahmed, Taushif; Mahakhud, Maguni; Mathews, Prakash; Rana, Narayan; Ravindran, V.

    2014-05-01

    We present the virtual QCD corrections to the process h → g + g + g due to interference of born and two-loop amplitudes, where h is a massive spin-2 particle and g is the gluon. We assume that the SM fields couple to h through the SM energy momentum tensor. Our result constitutes one of the ingredients to full NNLO QCD contribution to production of a massive spin-2 particle along with a jet in the scattering process at the LHC. In particular, this massive spin-2 could be a KK mode of a ADD graviton in large extra dimensional model or a RS KK mode in warped extra dimensional model or a generic massive spin-2. In addition, it provides an opportunity to study the ultraviolet and infrared structures of QCD amplitudes involving tensorial coupling resulting from energy momentum operator. Using dimensional regularization, we find that infrared poles of this amplitude are in agreement with the proposal by Catani confirming the factorization property of QCD amplitudes with tensorial insertion.

  11. Constraints on the evolutionary mechanisms of massive galaxies since z ∼ 1 from their velocity dispersions

    NASA Astrophysics Data System (ADS)

    Peralta de Arriba, L.; Balcells, M.; Trujillo, I.; Falcón-Barroso, J.; Tapia, T.; Cardiel, N.; Gallego, J.; Guzmán, R.; Hempel, A.; Martín-Navarro, I.; Pérez-González, P. G.; Sánchez-Bláquez, P.

    2015-10-01

    Several authors have reported that the dynamical masses of massive compact galaxies (M* ≳ 1011 M⊙, re ∼ 1 kpc), computed as Mdyn = 5.0 σe2 re/G, are lower than their stellar masses M*. In a previous study from our group, the discrepancy is interpreted as a breakdown of the assumption of homology that underlie the Mdyn determinations. Here, we present new spectroscopy of six redshift z ≈ 1.0 massive compact ellipticals from the Extended Groth Strip, obtained with the 10.4 m Gran Telescopio Canarias. We obtain velocity dispersions in the range 161-340 km s-1. As found by previous studies of massive compact galaxies, our velocity dispersions are lower than the virial expectation, and all of our galaxies show Mdyn < M* (assuming a Salpeter initial mass function). Adding data from the literature, we build a sample covering a range of stellar masses and compactness in a narrow redshift range z ≈ 1.0. This allows us to exclude systematic effects on the data and evolutionary effects on the galaxy population, which could have affected previous studies. We confirm that mass discrepancy scales with galaxy compactness. We use the stellar mass plane (M*, σe, re) populated by our sample to constrain a generic evolution mechanism. We find that the simulations of the growth of massive ellipticals due to mergers agree with our constraints and discard the assumption of homology.

  12. 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.

  13. A massive binary black hole in 1928 + 738?

    NASA Astrophysics Data System (ADS)

    Roos, Nico; Kaastra, Jelle S.; Hummel, Christian A.

    1993-05-01

    We apply the binary black hole model to explain the wiggles in the milliarcsec radio jet of the superluminal quasar 1928 + 738 (4C 73.18) observed with VLBI at 1.3 cm wavelength by Hummel et al. (1992). The period and amplitude of the wiggles can be explained as due to the orbital motion of a binary black hole with mass of order l0 exp 8 solar masses, mass ratio larger than 0.1, and orbital radius about 10 exp 16 cm. The jet's inclination to the line of sight should be small confirming the standard interpretation of superluminal motion and one-sidedness as due to relativistic motion in a direction close to the line of sight. The small orbital radius suggests that the binary has been losing a significant amount of orbital energy during the last 10 exp 7 yr, possibly by interaction with the matter which is flowing through the active galactic nucleus. The arcsec-scale radio structure provides additional support for a link between activity and binary evolution. If our interpretation of the mass wiggle in this quasar is correct, then many other quasars may contain massive binary black holes as well.

  14. [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.

  15. Revisiting perturbations in extended quasidilaton massive gravity

    NASA Astrophysics Data System (ADS)

    Heisenberg, Lavinia

    2015-04-01

    In this work we study the theory of extended quasidilaton massive gravity together with the presence of matter fields. After discussing the homogeneous and isotropic fully dynamical background equations, which governs the exact expansion history of the universe, we consider small cosmological perturbations around these general FLRW solutions. The stability of tensor, vector and scalar perturbations on top of these general background solutions give rise to slightly different constraints on the parameters of the theory than those obtained in the approximative assumption of the late-time asymptotic form of the expansion history, which does not correspond to our current epoch. This opens up the possibility of stable FLRW solutions to be compared with current data on cosmic expansion with the restricted parameter space based on theoretical ground.

  16. Gravito-electromagnetic effects of massive rings

    NASA Astrophysics Data System (ADS)

    Ruggiero, Matteo Luca

    2015-05-01

    The Einstein field equations in linear post-Newtonian approximation can be written in analogy with electromagnetism, in the so-called gravito-electromagnetic (GEM) formalism. We use this analogy to study the gravitational field of a massive ring: In particular, we consider a continuous mass distribution on Keplerian orbit around a central body, and we work out the gravitational field generated by this mass distribution in the intermediate zone between the central body and the ring, focusing on the gravitomagnetic (GM) component that originates from the rotation of the ring. In doing so, we generalize and complement some previous results that focused on the purely Newtonian effects of the ring (thus neglecting its rotation) or that were applied to the case, of rotating spherical shells. Eventually, we study in some simple cases, the effect of the rotation of the ring, and suggest that, in principle, this approach could be used to infer information about the angular momentum of the ring.

  17. The Search for Stable, Massive, Elementary Particles

    SciTech Connect

    Kim, Peter C

    2001-02-14

    In this paper we review the experimental and observational searches for stable, massive, elementary particles other than the electron and proton. The particles may be neutral, may have unit charge or may have fractional charge. They may interact through the strong, electromagnetic, weak or gravitational forces or through some unknown force. The purpose of this review is to provide a guide for future searches--what is known, what is not known, and what appear to be the most fruitful areas for new searches. A variety of experimental and observational methods such as accelerator experiments, cosmic ray studies, searches for exotic particles in bulk matter and searches using astrophysical observations is included in this review.

  18. Massive neutrinos and invisible axion minimally connected

    NASA Astrophysics Data System (ADS)

    Bertolini, Stefano; Di Luzio, Luca; Kolešová, Helena; Malinský, Michal

    2015-03-01

    We survey a few minimal scalar extensions of the standard electroweak model that provide a simple setup for massive neutrinos in connection with an invisible axion. The presence of a chiral U (1 ) à la Peccei-Quinn drives the pattern of Majorana neutrino masses while providing a dynamical solution to the strong C P problem and an axion as a dark matter candidate. We paradigmatically apply such a renormalizable framework to type-II seesaw and to two viable models for neutrino oscillations where the neutrino masses arise at one and two loops, respectively. We comment on the naturalness of the effective setups as well as on their implications for vacuum stability and electroweak baryogenesis.

  19. 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.

  20. 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

  1. Four-dimensional unsubtraction with massive particles

    NASA Astrophysics Data System (ADS)

    Sborlini, Germán F. R.; Driencourt-Mangin, Félix; Rodrigo, Germán

    2016-10-01

    We extend the four-dimensional unsubtraction method, which is based on the loop-tree duality (LTD), to deal with processes involving heavy particles. The method allows to perform the summation over degenerate IR configurations directly at integrand level in such a way that NLO corrections can be implemented directly in four space-time dimensions. We define a general momentum mapping between the real and virtual kinematics that accounts properly for the quasi-collinear configurations, and leads to an smooth massless limit. We illustrate the method first with a scalar toy example, and then analyse the case of the decay of a scalar or vector boson into a pair of massive quarks. The results presented in this paper are suitable for the application of the method to any multipartonic process.

  2. 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.

  3. Mobil AG scores with massive frac

    SciTech Connect

    Bleakley, W.B.

    1984-01-01

    Mobil Oil AG, West Germany, added 20 bcf of natural gas to the field reserves and improved well productivity five-fold through a massive fracture of the Mainsand section of the Upper Rotliegendes formation in Soehlingen field. The frac job was the largest ever in Europe and is felt to be the world's largest in terms of sintered bauxite used. The fracture treatment also showed that it is possible to put 9,000 lb/min of bauxite into a hydraulically formed fracture. This is believed to be a record rate for this high-strength proppant. Mobil engineers feel, however, that Ottawa sand could probably be used, and they may try it if another opportunity presents itself.

  4. SATELLITE FORMATION from ancient massive rings

    NASA Astrophysics Data System (ADS)

    Crida, Aurélien; Charnoz, Sébastien

    2013-07-01

    When a planetary tidal disk - like Saturn's rings - spreads beyond the Roche radius (inside which planetary tides prevent aggregation), satellites form and migrate away. Here, we show that most regular satellites in the solar system probably formed in this way. According to our analytical model, when the spreading is slow, a retinue of satellites appear with masses increasing with distance to the Roche radius, in excellent agreement with Saturn's, Uranus', and Neptune's satellite systems. This suggests that Uranus and Neptune used to have massive rings that disappeared to give birth to most of their regular satellites. In contrast, when the spreading is fast, only one large satellite forms, as was the case for Pluto and Earth. This conceptually bridges the gap between terrestrial and giant planet systems. (Ref: Crida & Charnoz 2012, Science, 338, 1196-1199)

  5. 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

  6. 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.

  7. Learning from Massive Distributed Data Sets (Invited)

    NASA Astrophysics Data System (ADS)

    Kang, E. L.; Braverman, A. J.

    2013-12-01

    Technologies for remote sensing and ever-expanding computer experiments in climate science are generating massive data sets. Meanwhile, it has been common in all areas of large-scale science to have these 'big data' distributed over multiple different physical locations, and moving large amounts of data can be impractical. In this talk, we will discuss efficient ways for us to summarize and learn from distributed data. We formulate a graphical model to mimic the main characteristics of a distributed-data network, including the size of the data sets and speed of moving data. With this nominal model, we investigate the trade off between prediction accurate and cost of data movement, theoretically and through simulation experiments. We will also discuss new implementations of spatial and spatio-temporal statistical methods optimized for distributed data.

  8. Revisiting perturbations in extended quasidilaton massive gravity

    SciTech Connect

    Heisenberg, Lavinia

    2015-04-01

    In this work we study the theory of extended quasidilaton massive gravity together with the presence of matter fields. After discussing the homogeneous and isotropic fully dynamical background equations, which governs the exact expansion history of the universe, we consider small cosmological perturbations around these general FLRW solutions. The stability of tensor, vector and scalar perturbations on top of these general background solutions give rise to slightly different constraints on the parameters of the theory than those obtained in the approximative assumption of the late-time asymptotic form of the expansion history, which does not correspond to our current epoch. This opens up the possibility of stable FLRW solutions to be compared with current data on cosmic expansion with the restricted parameter space based on theoretical ground.

  9. 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.

  10. Matrix gravity and massive colored gravitons

    NASA Astrophysics Data System (ADS)

    Chamseddine, Ali H.

    2004-10-01

    We formulate a theory of gravity with a matrix-valued complex vierbein based on the SL(2N,C)⊗SL(2N,C) gauge symmetry. The theory is metric independent, and before symmetry breaking all fields are massless. The symmetry is broken spontaneously and all gravitons corresponding to the broken generators acquire masses. If the symmetry is broken to SL(2,C), then the spectrum would correspond to one massless graviton coupled to 2N2-1 massive gravitons. A novel feature is the way the fields corresponding to noncompact generators acquire kinetic energies with correct signs. Equally surprising is the way Yang-Mills gauge fields acquire their correct kinetic energies through the coupling to the nondynamical antisymmetric components of the vierbeins.

  11. 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).

  12. 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

  13. 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.

  14. [Treatment of the massive suprachoroidal hemorrhages].

    PubMed

    Pastor, J C; Baílez, C; Aragón, J; Rodríguez de la Rúa, E

    2001-04-01

    To analyze the anatomical and functional results obtained in post- surgical suprachoroidal hemorrhages treated from 1998 to 2000 and to review the information on the series of this complication that have been published during the last five years and which included at least 10 patients. A retrospective analysis of the medical records of patients with suprachoroidal hemorrhages at the Instituto Universitario de Oftalmobiología Aplicada (IOBA) - University Hospital of Valladolid. Bibliographic search by Med-Line/Pub Med from 1995 to 2000 was performed. 8 patients who fulfill these criteria have been treated and 8 papers, also complying with the criteria, have been found. The functional and anatomic results of post-surgical suprachoroidal hemorrhages are still poor, even though the prognosis seems to have improved in the last 20 years. The standardized classification of massive suprachoroidal hemorrhages based on severity and the standardization of the follow-up would improve these results.

  15. Quantized charge pump of massive Dirac electrons

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Liu, Jun-Feng

    2017-05-01

    We study a new scheme to realize a quantized two-parameter charge pump based on massive Dirac electrons. It is shown that the two time-dependent and out-of-phase staggered potentials introduced in graphene can pump out an integer number of electrons in a pumping cycle as long as the Fermi energy resides in the effective energy gap opened by pumping potentials. The dependence of the pumped charge per mode on the pumping phase or the dynamic phase exhibits a binary alternation from +e to -e . This quantization has a topological origin and can be accounted for by adiabatic evolution of the topologically protected interfacial state forming between the two pumping sources.

  16. Holographic Josephson junction from massive gravity

    NASA Astrophysics Data System (ADS)

    Hu, Ya-Peng; Li, Huai-Fan; Zeng, Hua-Bi; Zhang, Hai-Qing

    2016-05-01

    We study the holographic superconductor-normal metal-superconductor (SNS) Josephson junction in de Rham-Gabadadze-Tolley massive gravity. If the boundary theory is independent of spatial directions, i.e., if the chemical potential is homogeneous in spatial directions, we find that the graviton mass parameter will make it more difficult for the normal metal-superconductor phase transition to take place. In the holographic model of the Josephson junction, it is found that the maximal tunneling current will decrease according to the graviton mass parameter. Besides, the coherence length of the junction decreases as well with respect to the graviton mass parameter. If one interprets the graviton mass parameter as the effect of momentum dissipation in the boundary field theory, this indicates that the stronger the momentum dissipation is, the smaller the coherence length is.

  17. Computational chaos in massively parallel neural networks

    NASA Technical Reports Server (NTRS)

    Barhen, Jacob; Gulati, Sandeep

    1989-01-01

    A fundamental issue which directly impacts the scalability of current theoretical neural network models to massively parallel embodiments, in both software as well as hardware, is the inherent and unavoidable concurrent asynchronicity of emerging fine-grained computational ensembles and the possible emergence of chaotic manifestations. Previous analyses attributed dynamical instability to the topology of the interconnection matrix, to parasitic components or to propagation delays. However, researchers have observed the existence of emergent computational chaos in a concurrently asynchronous framework, independent of the network topology. Researcher present a methodology enabling the effective asynchronous operation of large-scale neural networks. Necessary and sufficient conditions guaranteeing concurrent asynchronous convergence are established in terms of contracting operators. Lyapunov exponents are computed formally to characterize the underlying nonlinear dynamics. Simulation results are presented to illustrate network convergence to the correct results, even in the presence of large delays.

  18. 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.

  19. Effect of massive disks on bulge isophotes

    SciTech Connect

    Monet, D.G.; Richstone, D.O.; Schechter, P.L.

    1981-04-15

    Massive disks produce flattened equipotentials. Unless the stars in a galaxy bulge are preferentially hotter in the z direction than in the plane, the isophotes will be at least as flat as the equipotentials. The comparison of two galaxy models having flat rotation curves with the available surface photometry for five external galaxies does not restrict the mass fraction which might reside in the disk. However, star counts in our own Galaxy indicate that unless the disk terminates close to the solar circle, no more than half the mass within that circle lies in the disk. The remaining half must lie either in the bulge or, more probably, in a third dark, round, dynamically distinct component.

  20. Neutrinos and the Deaths of Massive Stars

    NASA Astrophysics Data System (ADS)

    Hix, W. R.; Mezzacappa, A.; Messer, O. E. B.

    2005-06-01

    Observationally categorized as Type II or Ib/c supernovae, core collapse supernovae mark the end of the life of a massive star and the formation of a neutron star or black hole. These explosions are among the most energetic events in the universe, emitting 1046 J of energy, primarily in the form of neutrinos. They play a preeminent role in the cosmic origin of the elements and serve as a principal heating mechanism for the interstellar medium. Numerical simulations of the textbook neutrino-reheating mechanism for core collapse supernovae frequently fail to match the most fundamental observable property: an explosion with roughly 1044 J of kinetic energy. We review recent improvements in the modeling of core collapse supernovae, including improved tracking of the neutrino distribution and better accounting for the multi-dimensional nature of the hydrodynamic flows. We also discuss how continued improvements in the treatment of microscopic nuclear and neutrino physics has important macroscopic consequences.

  1. Plasma simulation using the massively parallel processor

    NASA Technical Reports Server (NTRS)

    Lin, C. S.; Thring, A. L.; Koga, J.; Janetzke, R. W.

    1987-01-01

    Two dimensional electrostatic simulation codes using the particle-in-cell model are developed on the Massively Parallel Processor (MPP). The conventional plasma simulation procedure that computes electric fields at particle positions by means of a gridded system is found inefficient on the MPP. The MPP simulation code is thus based on the gridless system in which particles are assigned to processing elements and electric fields are computed directly via Discrete Fourier Transform. Currently, the gridless model on the MPP in two dimensions is about nine times slower that the gridded system on the CRAY X-MP without considering I/O time. However, the gridless system on the MPP can be improved by incorporating a faster I/O between the staging memory and Array Unit and a more efficient procedure for taking floating point sums over processing elements. The initial results suggest that the parallel processors have the potential for performing large scale plasma simulations.

  2. 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

  3. 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.

  4. Massive = 2 supergravity in three dimensions

    NASA Astrophysics Data System (ADS)

    Alkaç, Gökhan; Basanisi, Luca; Bergshoeff, Eric A.; Ozkan, Mehmet; Sezgin, Ergin

    2015-02-01

    There exists two distinct off-shell = 2 supergravities in three dimensions. They are also referred to as = (1, 1) and = (2, 0) supergravities, and they arise from the coupling of the Weyl multiplet to a compensating scalar or vector multiplet, respectively, followed by fixing of conformal symmetries. The = ( p, q) terminology refers to the underlying anti-de Sitter superalgebras OSp(2, p) ⊕ OSp(2, q) with R-symmetry group SO( p) × SO( q). We construct off-shell invariants of these theories up to fourth order in derivatives. As an application of these results, we determine the special combinations of the = (1, 1) invariants that admit anti-de Sitter vacuum solution about which there is a ghost-free massive spin-2 multiplet of propagating modes. We also show that the =(2,0) invariants do not allow such possibility.

  5. Compton scattering vertex for massive scalar QED

    SciTech Connect

    Bashir, A.; Concha-Sanchez, Y.; Delbourgo, R.; Tejeda-Yeomans, M. E.

    2009-08-15

    We investigate the Compton scattering vertex of charged scalars and photons in scalar quantum electrodynamics (SQED). We carry out its nonperturbative construction consistent with Ward-Fradkin-Green-Takahashi identity which relates 3-point vertices to the 4-point ones. There is an undetermined part which is transverse to one or both the external photons, and needs to be evaluated through perturbation theory. We present in detail how the transverse part at the 1-loop order can be evaluated for completely general kinematics of momenta involved in covariant gauges and dimensions. This involves the calculation of genuine 4-point functions with three massive propagators, the most nontrivial integrals reported in this paper. We also discuss possible applications of our results.

  6. Aerodynamic simulation on massively parallel systems

    NASA Technical Reports Server (NTRS)

    Haeuser, Jochem; Simon, Horst D.

    1992-01-01

    This paper briefly addresses the computational requirements for the analysis of complete configurations of aircraft and spacecraft currently under design to be used for advanced transportation in commercial applications as well as in space flight. The discussion clearly shows that massively parallel systems are the only alternative which is both cost effective and on the other hand can provide the necessary TeraFlops, needed to satisfy the narrow design margins of modern vehicles. It is assumed that the solution of the governing physical equations, i.e., the Navier-Stokes equations which may be complemented by chemistry and turbulence models, is done on multiblock grids. This technique is situated between the fully structured approach of classical boundary fitted grids and the fully unstructured tetrahedra grids. A fully structured grid best represents the flow physics, while the unstructured grid gives best geometrical flexibility. The multiblock grid employed is structured within a block, but completely unstructured on the block level. While a completely unstructured grid is not straightforward to parallelize, the above mentioned multiblock grid is inherently parallel, in particular for multiple instruction multiple datastream (MIMD) machines. In this paper guidelines are provided for setting up or modifying an existing sequential code so that a direct parallelization on a massively parallel system is possible. Results are presented for three parallel systems, namely the Intel hypercube, the Ncube hypercube, and the FPS 500 system. Some preliminary results for an 8K CM2 machine will also be mentioned. The code run is the two dimensional grid generation module of Grid, which is a general two dimensional and three dimensional grid generation code for complex geometries. A system of nonlinear Poisson equations is solved. This code is also a good testcase for complex fluid dynamics codes, since the same datastructures are used. All systems provided good speedups, but

  7. Aerodynamic simulation on massively parallel systems

    NASA Technical Reports Server (NTRS)

    Haeuser, Jochem; Simon, Horst D.

    1992-01-01

    This paper briefly addresses the computational requirements for the analysis of complete configurations of aircraft and spacecraft currently under design to be used for advanced transportation in commercial applications as well as in space flight. The discussion clearly shows that massively parallel systems are the only alternative which is both cost effective and on the other hand can provide the necessary TeraFlops, needed to satisfy the narrow design margins of modern vehicles. It is assumed that the solution of the governing physical equations, i.e., the Navier-Stokes equations which may be complemented by chemistry and turbulence models, is done on multiblock grids. This technique is situated between the fully structured approach of classical boundary fitted grids and the fully unstructured tetrahedra grids. A fully structured grid best represents the flow physics, while the unstructured grid gives best geometrical flexibility. The multiblock grid employed is structured within a block, but completely unstructured on the block level. While a completely unstructured grid is not straightforward to parallelize, the above mentioned multiblock grid is inherently parallel, in particular for multiple instruction multiple datastream (MIMD) machines. In this paper guidelines are provided for setting up or modifying an existing sequential code so that a direct parallelization on a massively parallel system is possible. Results are presented for three parallel systems, namely the Intel hypercube, the Ncube hypercube, and the FPS 500 system. Some preliminary results for an 8K CM2 machine will also be mentioned. The code run is the two dimensional grid generation module of Grid, which is a general two dimensional and three dimensional grid generation code for complex geometries. A system of nonlinear Poisson equations is solved. This code is also a good testcase for complex fluid dynamics codes, since the same datastructures are used. All systems provided good speedups, but

  8. The Deuteration Clock for Massive Starless Cores

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

  9. 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.

  10. 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

  11. 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

  12. Due process traditionalism.

    PubMed

    Sunstein, Cass R

    2008-06-01

    In important cases, the Supreme Court has limited the scope of "substantive due process" by reference to tradition, but it has yet to explain why it has done so. Due process traditionalism might be defended in several distinctive ways. The most ambitious defense draws on a set of ideas associated with Edmund Burke and Friedrich Hayek, who suggested that traditions have special credentials by virtue of their acceptance by many minds. But this defense runs into three problems. Those who have participated in a tradition may not have accepted any relevant proposition; they might suffer from a systematic bias; and they might have joined a cascade. An alternative defense sees due process traditionalism as a second-best substitute for two preferable alternatives: a purely procedural approach to the Due Process Clause, and an approach that gives legislatures the benefit of every reasonable doubt. But it is not clear that in these domains, the first-best approaches are especially attractive; and even if they are, the second-best may be an unacceptably crude substitute. The most plausible defense of due process traditionalism operates on rule-consequentialist grounds, with the suggestion that even if traditions are not great, they are often good, and judges do best if they defer to traditions rather than attempting to specify the content of "liberty" on their own. But the rule-consequentialist defense depends on controversial and probably false assumptions about the likely goodness of traditions and the institutional incapacities of judges.

  13. 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.

  14. The influence of feedback from massive stars on the formation and emergence of massive clusters

    NASA Astrophysics Data System (ADS)

    Dale, James E.

    2017-03-01

    Massive star clusters are of fundamental importance both observationally, since they are visible at such great distances, and theoretically, because of their influence on the large-scale ISM. Understanding stellar feedback is a prerequisite for making sense of their formation and early evolution, since feedback influences cluster structure, star formation efficiency, and sets the timescales on which clusters emerge from their parent clouds to become optically visible. I review the progress made in understanding these issues from a numerical perspective.

  15. A MASSIVE PROTOSTAR FORMING BY ORDERED COLLAPSE OF A DENSE, MASSIVE CORE

    SciTech Connect

    Zhang, Yichen; Tan, Jonathan C.; Telesco, Charles; De Buizer, James M.; Sandell, Goeran; Shuping, Ralph; Beltran, Maria T.; Churchwell, Ed; Whitney, Barbara; McKee, Christopher F.; Staff, Jan E.

    2013-04-10

    We present 30 and 40 {mu}m imaging of the massive protostar G35.20-0.74 with SOFIA-FORCAST. The high surface density of the natal core around the protostar leads to high extinction, even at these relatively long wavelengths, causing the observed flux to be dominated by that emerging from the near-facing outflow cavity. However, emission from the far-facing cavity is still clearly detected. We combine these results with fluxes from the near-infrared to mm to construct a spectral energy distribution (SED). For isotropic emission the bolometric luminosity would be 3.3 Multiplication-Sign 10{sup 4} L{sub Sun }. We perform radiative transfer modeling of a protostar forming by ordered, symmetric collapse from a massive core bounded by a clump with high-mass surface density, {Sigma}{sub cl}. To fit the SED requires protostellar masses {approx}20-34 M{sub Sun} depending on the outflow cavity opening angle (35 Degree-Sign -50 Degree-Sign ), and {Sigma}{sub cl} {approx} 0.4-1 g cm{sup -2}. After accounting for the foreground extinction and the flashlight effect, the true bolometric luminosity is {approx}(0.7-2.2) Multiplication-Sign 10{sup 5} L{sub Sun }. One of these models also has excellent agreement with the observed intensity profiles along the outflow axis at 10, 18, 31, and 37 {mu}m. Overall our results support a model of massive star formation involving the relatively ordered, symmetric collapse of a massive, dense core and the launching bipolar outflows that clear low-density cavities. Thus a unified model may apply for the formation of both low- and high-mass stars.

  16. Should warm fresh whole blood be the first choice in acute massive hemorrhage in emergency conditions?

    PubMed

    Kendigelen, Pınar; Kamalak, Zeynep; Abat, Deniz

    2016-03-01

    Early management of rapid massive hemorrhage requires early administration of blood products and rapid surgical control of bleeding. Professionals in peripheral hospitals with limited resources often work under conditions similar to those in the military. Described in the present report are 3 cases in which warm fresh whole blood (WFWB) was used in patients with massive bleeding who presented to a peripheral hospital that had no blood products suitable for emergency conditions. Described first is the case of a 16-year-old female patient who underwent emergency cesarean section. The patient had massive bleeding from the uterus due to atony. Her hemoglobin (Hb) dropped to 3.5 g/dL. Six units of WFWB were transfused during surgery. Hemodynamic parameters and complete blood count (CBC) stabilized. She was transferred from the intensive care unit (ICU) to obstetrics on day 2 and was discharged on day 7. Described second is the case of a 35-year-old female patient who also underwent emergency cesarean section, and for whom massive bleeding was due to uterine atony. Hb dropped to 2 g/dL and hematocrit (HCT) to 5.4%. Nine units of WFWB were transfused, after which hemodynamic and laboratory parameters stabilized. The patient was extubated the following day, transferred from the ICU to obstetrics on day 3, and was discharged on day 8. Described third is the case of a 36-year-old male patient with stab injuries and hemorrhagic shock who underwent emergency surgery. The patient had injuries to the right renal artery and kidney. Nine units of WFWB were transfused due to continued hemorrhage during surgery. Following surgical control of bleeding and transfusion, hemodynamic parameters improved. The patient was transferred from the ICU on day 5 and discharged on day 10. WFWB transfusion nearly disappeared from civilian medicine after blood was separated into components, and whole blood is not usually available at blood banks. In massive transfusions, WFWB effectively replaces

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. Inverse relationship between cirrhosis and massive tumours in hepatocellular carcinoma

    PubMed Central

    Sarpel, Umut; Ayo, Diego; Lobach, Iryna; Xu, Ruliang; Newman, Elliot

    2012-01-01

    Background A subset of patients with hepatocellular carcinoma (HCC) present with massive tumours. It is unknown why certain patients develop these massive tumours, and whether this presentation is specific to the underlying viral aetiology or patient demographics such as gender, race and age. Methods All patients with HCC at Bellevue Hospital Center, New York from 1998 to 2012 were identified and relevant demographic and clinical information was collected. Computed tomography/magnetic resonance imaging (CT/MRI) images were reviewed and the maximal tumour diameter on axial sections was recorded. Cirrhosis was defined histologically or by radiographical criteria. The two cohorts of massive and non-massive HCC were compared. Results A total of 361 patients with HCC were identified, of which 58 were categorized as having a massive HCC using a 13 cm size cut-off. Univariate and multivariate analysis demonstrated a significant association of massive HCC with age <40 years; hepatitis B or Asian ethnicity; and a lack of cirrhosis or platelet count >100. Discussion Massive HCC represents a tumour subtype that is associated with young, chronic hepatitis B carriers with non-cirrhotic livers. The clinical implications of this finding are that patients with massive HCC are typically excellent resection candidates barring the presence of gross vascular invasion or distant metastases. PMID:23043662

  2. 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.

  3. Candidate X-Ray-emitting OB Stars in MYStIX Massive Star-forming Regions

    NASA Astrophysics Data System (ADS)

    Povich, Matthew S.; Busk, Heather A.; Feigelson, Eric D.; Townsley, Leisa K.; Kuhn, Michael A.

    2017-03-01

    Massive O-type and early B-type (OB) stars in the nearby Galaxy remain incompletely cataloged due to high extinction, bright visible and infrared nebular emission in H ii regions, and high field star contamination. These difficulties are alleviated by restricting the search to stars with X-ray emission. Using the X-ray point sources from the Massive Young Star-forming Complex Study in Infrared and X-Rays (MYStIX) survey of OB-dominated regions, we identify 98 MYStIX candidate OB (MOBc) stars by fitting their 1-8 μm spectral energy distributions (SEDs) with reddened stellar atmosphere models. We identify 27 additional MOBc stars based on JHK S photometry of X-ray stars lacking SED fitting. These candidate OB stars indicate that the current census of stars earlier than B1, taken across the 18 MYStIX regions studied, is less than 50% complete. We also fit the SEDs of 239 previously published OB stars to measure interstellar extinction and bolometric luminosities, revealing six candidate massive binary systems and five candidate O-type (super)giants. As expected, candidate OB stars have systematically higher extinction than previously published OB stars. Notable results for individual regions include identification of the OB population of a recently discovered massive cluster in NGC 6357, an older OB association in the M17 complex, and new massive luminous O stars near the Trifid Nebula. In several relatively poorly studied regions (RCW 38, NGC 6334, NGC 6357, Trifid, and NGC 3576), the OB populations may increase by factors of ≳ 2.

  4. An Emerging Wolf-Rayet Massive Star Cluster in NGC 4449

    NASA Astrophysics Data System (ADS)

    Sokal, Kimberly R.; Johnson, Kelsey E.; Indebetouw, Rémy; Reines, Amy E.

    2015-03-01

    We present a panchromatic investigation of the partially embedded, emerging massive cluster Source 26 (=S26) in NGC 4449 with optical spectra obtained at Apache Point Observatory and archival Hubble, Spitzer, and Herschel 5 Space Telescope images. First identified as a radio continuum source with a thermal component due to ionized material, the massive cluster S26 also exhibits optical Wolf-Rayet (WR) emission lines that reveal a large evolved massive star population. We find that S26 is host to ˜240 massive stars, of which ˜18 are WR stars; the relative populations are roughly consistent with other observed massive star-forming clusters and galaxies. We construct SEDs over two spatial scales (˜100 and ˜300 pc) that clearly exhibit warm dust and polycyclic aromatic hydrocarbon (PAH) emission. The best fit dust and grain models reveal that both the intensity of the exciting radiation and PAH grain destruction increase toward the cluster center. Given that the timescale of evacuation is important for the future dynamical evolution of the cluster, it is important to determine whether O-type and WR stars can evacuate the material gradually before supernova do so on a much faster timescale. With a minimum age of ≈ 3 Myr, it is clear that S26 has not yet fully evacuated its natal material, which indicates that unevolved O-type stars alone do not provide sufficient feedback to remove the gas and dust. We hypothesize that the feedback of WR stars in this cluster may be necessary for clearing the material from the gravitational potential of the cluster. We find S26 is similar to emission line clusters observed in the Antennae galaxies and may be considered a younger analog to 30 Doradus in the LMC.

  5. The cosmic assembly of stellar haloes in massive early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Buitrago, Fernando; Trujillo, Ignacio; Curtis-Lake, Emma; Montes, Mireia; Cooper, Andrew P.; Bruce, Victoria A.; Pérez-González, Pablo G.; Cirasuolo, Michele

    2017-04-01

    Using the exquisite depth of the Hubble Ultra Deep Field (HUDF12 programme) data set, we explore the ongoing assembly of the outermost regions of the most massive galaxies (Mstellar ≥ 5× 1010 M⊙) at z ≤ 1. The outskirts of massive objects, particularly early-type Galaxies (ETGs), are expected to suffer a dramatic transformation across cosmic time due to continuous accretion of small galaxies. HUDF imaging allows us to study this process at intermediate redshifts in six massive galaxies, exploring the individual surface brightness profiles out to ˜25 effective radii. We find that 5-20 per cent of the total stellar mass for the galaxies in our sample is contained within 10 < R < 50 kpc. These values are in close agreement with numerical simulations, and higher than those reported for local late-type galaxies (≲5 per cent). The fraction of stellar mass stored in the outer envelopes/haloes of massive ETGs increases with decreasing redshift, being 28.7 per cent at = 0.1, 15.1 per cent at = 0.65 and 3.5 per cent at = 2. The fraction of mass in diffuse features linked with ongoing minor merger events is >1-2 per cent, very similar to predictions based on observed close pair counts. Therefore, the results for our small albeit meaningful sample suggest that the size and mass growth of the most massive galaxies have been solely driven by minor and major merging from z = 1 to today.

  6. 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.

  7. 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

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

    PubMed

    Martines, F; Immordino, V

    2009-10-01

    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 amygdala region).

  9. VLBI multi-epoch water maser observations toward massive protostars

    NASA Astrophysics Data System (ADS)

    Torrelles, José M.; Gómez, José F.; Patel, Nimesh A.; Curiel, Salvador; Anglada, Guillem; Estalella, Robert

    2012-07-01

    VLBI multi-epoch water maser observations are a powerful tool to study the gas very close to the central engine responsible for the phenomena associated with the early evolution of massive protostars. In this paper we present a summary of the main observational results obtained toward the massive star-forming regions of Cepheus A and W75N. These observations revealed unexpected phenomena in the earliest stages of evolution of massive objects (e.g., non-collimated ``short-lived'' pulsed ejections in different massive protostars), and provided new insights in the study of the dynamic scenario of the formation of high-mass stars (e.g., simultaneous presence of a jet and wide-angle outflow in the massive object Cep A HW2, similar to what is observed in low-mass protostars). In addition, with these observations it has been possible to identify new, previously unseen centers of high-mass star formation through outflow activity.

  10. 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.

  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. Fragmentation of Molecular Clumps and Formation of Massive Cores

    NASA Astrophysics Data System (ADS)

    Zhang, Qizhou

    2014-07-01

    Massive protostars are born in parsec-scale molecular clumps that collapse and fragment, leading to the formation of a cluster of stellar objects. The interplay among gravity, turbulence and magnetic fields affects the outcome of fragmentation. The physical condition (temperature and density) in molecular clumps limits the Jeans mass to about 1 Msun. This creates a theoretical puzzle for massive star formation since dense cores much larger than 1 Msun tend to further fragment into lower mass entities. In this talk, I will present recent high resolution observations of massive molecular clumps at very early evolutionary stages. I will discuss fragmentation, physical and chemical evolution of molecular coresand the implication of these findings to current theoretical ideas of massive star and cluster formation. I will also present measurements of dust polarization of a large sample of massive molecular clumps, which suggest that magnetic fields play an important role during the collapse of molecular clumps and the formation of dense cores.

  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. Massive black holes in dense star clusters

    NASA Astrophysics Data System (ADS)

    Gurkan, Mehmet Atakan

    2005-11-01

    In this thesis, we study the formation of massive black holes in dense star clusters and their effects on the clusters' further evolution. We determine the necessary conditions for early core collapse, leading to the formation of a very massive star via runaway collisions. This process provides a natural mechanism for the formation of intermediate-mass black holes in young dense star clusters, which have been inferred from recent X-ray and optical observations. We performed about a hundred N -body simulations using our Monte Carlo technique, with a wide variety of initial conditions, containing up to 10 7 stars from a broad initial mass distribution. We find that for realistic initial mass functions, mass segregation and dynamical instabilities reduce the core collapse time, t cc , by two orders of magnitude compared to single- component cluster models. The ratio of the core collapse time to central relaxation time is generally ~0.15, which translates into ~0.07 for ratio of core collapse time to half-mass relaxation time for moderately concentrated clusters. This ratio can be smaller if there is initial mass segregation. We also find that typically the mass of the stars in the collapsing core is ~0.2% of the cluster's total mass. We then study the inspiral towards the Galactic center of young clusters which undergo early core collapse. We find that such clusters can bring many young stars to the central parsec, and hence explain the presence of many young stars in this region. However, this mechanism requires a large initial mass, and deposits more stars, both in the central parsec and outside it, than observed. We provide possible explanations for this discrepancy, and suggest future directions for research. Finally, we study the effects of primordial binaries on early core collapse runaway collisions. Even though such binaries generally delay and prevent core collapse (e.g., in globular clusters) they are expected to facilitate collisions and hence accelerate

  16. 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.

  17. 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

  18. Can gravitational microlensing be used to probe geometry of a massive black-hole?

    NASA Astrophysics Data System (ADS)

    Popović, Luka Č.; Jovanović, Predrag

    2007-04-01

    Astronomical Observatory, Belgrade, Yugoslavia (Serbia and Montenegro) Here we discuss the possibility to use gravitational microlensing in order to probe the geometry around a massive black hole. Taking into account that lensed quasars are emitting X-rays which come from the heart of these objects (around a massive black hole), we investigated the influence of microlensing on the shape of the X-ray continuum/Fe K-alpha line variability due to microlensing by stars from a foreground galaxy [1,2]. We considered an X-ray accretion disk in Schwarzschild and Kerr metrics that is microlensed by a straight-fold caustic and a magnification pattern [2]. We found that the changes in the shape of the X-ray continuum as well as Fe K-alpha line due to microlensing depend on assumed metrics. This shows that microlensing can be used to investigate an unresolved X-ray emitting region geometry around massive black holes. [1] Popović, L.Č., Mediavilla, E.G.; Jovanović, P., Muñoz, J.A. 2003 A& A...398..975P [2] Popović, L. Č., Jovanović, P., Mediavilla, E.; Zakharov, A. F.; Abajas, C.; Muñoz, J. A.; Chartas, G. 2005, ApJ (to be published in February 2006; astro-ph /0510271).

  19. 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

  20. Massive deformations of rank-2 symmetric tensor theory (a.k.a. BRS characterization of Fierz-Pauli massive gravity)

    NASA Astrophysics Data System (ADS)

    Blasi, Alberto; Maggiore, Nicola

    2017-01-01

    In this paper we consider the issue of massive gravity from a pure field theoretical point of view, as the massive deformation of the gauge theory for a symmetric rank-2 tensor field. We look for the most general massive theory with well defined propagators, imposing the absence of unphysical poles. We find several possibilities, depending on the choice of the gauge fixing term. Amongst these, two solutions with good massless limit are found. The request of the absence of tachyons, alone, does not isolate the Fierz-Pauli case: several examples of massive theories, which may or may not include the Fierz-Pauli mass term, are given. On the other hand, the Fierz-Pauli theory can be uniquely identified by means of a symmetry: it turns out the the Fierz-Pauli massive gravity is the only element of the cohomology of a BRS operator.