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Sample records for original four-lumen double-balloon

  1. Percutaneous balloon pericardiotomy: a double-balloon technique.

    PubMed

    Iaffaldano, R A; Jones, P; Lewis, B E; Eleftheriades, E G; Johnson, S A; McKiernan, T L

    1995-09-01

    We describe a double-balloon technique for performing a percutaneous balloon pericardiotomy. This technique was employed when the large, single dilation balloon customarily used for this procedure failed to fully inflate across the parietal pericardium. Two smaller balloons were advanced through the same skin tract and simultaneously inflated, thus producing an adequate pericardial window. This double-balloon technique allowed for the more secure anchoring of the balloons across the pericardium and for the delivery of greater dilation pressures.

  2. Double-Balloon Catheter for Isolated Liver Perfusion: An Experimental Study

    SciTech Connect

    Cwikiel, Wojciech; Bergqvist, Lennart; Harnek, Jan

    2001-05-15

    Purpose: Further development of a previously described interventional method for isolated liver perfusion (ILP) with a new double-lumen balloon catheter, and evaluation of the side-effects of such isolation.Methods: In six pigs a double-balloon occlusion catheter was placed via the transjugular approach with its tip in the portal vein. One of the balloons was positioned in the inferior vena cava (IVC), cranial to the origin of the hepatic veins and the other balloon in the portal vein. By the transfemoral approach, a single-balloon occlusion catheter was placed in the IVC caudal to the origin of the hepatic veins. A third catheter was placed by the transfemoral route with the occlusion balloon in the proper hepatic artery. After inflation of all balloons {sup 99}Tc{sup m}-labelled human serum albumin was recirculated through the liver. The isolation was evaluated by repeated measurement of radioactivity levels in peripheral blood. Laboratory tests of liver and pancreas function, and hemoglobin, were taken before, at the end of, and 3 days after the procedure. Blood gases were tested at the beginning and end of the procedure.Results: One pig died during the procedure due to technical failure and was excluded from the study. In the other pigs leakage from the isolated liver to the systemic circulation increased slowly, up to 9.7% (mean) during 30 min of recirculation of the perfusate through the liver. Laboratory tests were normal in all pigs except insignificant acidosis directly after the procedure and the slight elevation of s-ALAT after 3 days.Conclusions: Only minor leakage from the liver to the systemic circulation was noted during ILP performed with a new, double-balloon catheter. There were no serious side effects.

  3. Diagnostic and Therapeutic Capability of Double-Balloon Enteroscopy in Clinical Practice

    PubMed Central

    Akyuz, Umit; Akyuz, Filiz

    2016-01-01

    Advances in technology have facilitated the common use of small-bowel imaging. Intraoperative enteroscopy was the gold standard method for small-bowel imaging. However, noninvasive capsule endoscopy and invasive balloon enteroscopy are currently the main endoscopic procedures that are routinely used for small-bowel pathologies, and the indications for both techniques are similar. Although obstruction is a contraindication for capsule endoscopy, it is not considered to be problematic for double-balloon enteroscopy. The most important advantage of double-balloon enteroscopy is the applicability of therapeutic interventions during the procedure; however, double-balloon enteroscopy has certain advantages as well as disadvantages. PMID:26950010

  4. Double-balloon enteroscopy in small bowel diseases

    PubMed Central

    Chen, Wen-Guo; Shan, Guo-Dong; Zhang, Hong; Yang, Ming; L, Lin; Yue, Min; Chen, Guang-Wu; Gu, Qing; Zhu, Hua-Tuo; Xu, Guo-Qiang; Chen, Li-Hua

    2016-01-01

    Abstract The aim of the study was to evaluate the diagnostic and therapeutic value of double-balloon entoroscopy (DBE) in small bowel diseases (SBDs) in China. A retrospective review of 674 consecutive patients who underwent DBE between January 2007 and November 2015 was conducted. Patients were divided into 3 groups by age, young group (<45 years), middle-aged group (45–65 years), and elderly group (>65 years). Data were collected with regard to demographics, clinical, endoscopic findings, complications, diagnostic yield, and management. A total of 729 DBE procedures were performed successfully in our series. More than 20 types of SBDs were found with the detection rate of 70.9%(517/729). The majority of patients were Crohn's disease (33.4%,225/674), followed by tumor (18.8%,127/674) and angioectasia (7.9%, 53/674). Endoscopic treatment was performed in 60 patients in which hemostasis (17,28.3%) and polypectomy (15,25%) were the predominant form of intervention used. Adverse events occurred in 6 patients (0.96%,6/729) including perforation, hemorrhage, aspiration pneumonia. No acute pancreatitis or other major complications occurred. Adenocarcinoma, GIST, and lymphoma were the most common tumor detected, the majority of tumors located in the jejunum (56.7%), The detection rate of angioectasia was also higher in the jejunum (54.7%),77.8% of Crohn's disease was located in the ileum. The positive rate of DBE in small bowel tumor and Crohn's disease were significantly higher than that of angioectasia (P<0.05). In young cohort, Crohn's disease (48.1%) was the most commonly diseases followed by tumor (10.4%) and nonspecific enteritis (7.1%). Yet in the elderly group, the majority of patients were tumor (27.6%); angioectasia (21.3%) was also detected frequently. The positive rate of capsule endoscopy was 75.44 %(202/268) which was a little high than DBE (67.9%, 182/268) (P > 0.05). The obscure gastrointestinal bleeding (OGIB) was the most common indication, and

  5. Double Balloon Cervical Ripening Catheter for Control of Massive Hemorrhage in a Cervical Ectopic Pregnancy

    PubMed Central

    Zambrano, Nabila; Reilly, James; Moretti, Michael

    2017-01-01

    Cervical pregnancy can be complicated by perfuse vaginal bleeding. Mechanical compression directed at tamponing the cervical vessels can control hemostasis. There are several types of balloon catheters that have been described for cervical compression. However use of a double balloon catheter is a novel approach for cervical tamponade, as one balloon is positioned below the external cervical os and the second balloon is situated above in the internal cervical os. This compresses the cervix from internal os to external os between the two balloons, forming a “cervical sandwich.” We describe this method of cervical tamponade using a silicone double balloon cervical ripening catheter that rapidly controlled hemorrhage in a patient that failed conservative management with methotrexate. PMID:28261511

  6. Double Balloon Cervical Ripening Catheter for Control of Massive Hemorrhage in a Cervical Ectopic Pregnancy.

    PubMed

    Zambrano, Nabila; Reilly, James; Moretti, Michael; Lakhi, Nisha

    2017-01-01

    Cervical pregnancy can be complicated by perfuse vaginal bleeding. Mechanical compression directed at tamponing the cervical vessels can control hemostasis. There are several types of balloon catheters that have been described for cervical compression. However use of a double balloon catheter is a novel approach for cervical tamponade, as one balloon is positioned below the external cervical os and the second balloon is situated above in the internal cervical os. This compresses the cervix from internal os to external os between the two balloons, forming a "cervical sandwich." We describe this method of cervical tamponade using a silicone double balloon cervical ripening catheter that rapidly controlled hemorrhage in a patient that failed conservative management with methotrexate.

  7. Successful treatment of early-stage jejunum adenocarcinoma by endoscopic mucosal resection using double-balloon endoscopy: a case report.

    PubMed

    Suzuki, Hirobumi; Yamada, Atsuo; Watabe, Hirotsugu; Kobayashi, Yuka; Hirata, Yoshihiro; Yamaji, Yutaka; Yoshida, Haruhiko; Koike, Kazuhiko

    2012-01-01

    Small bowel adenocarcinoma (SBA) has generally been considered to have a poor prognosis because of nonspecific presentations and difficulties in detection of the disease. The advent of capsule endoscopy (CE) and double-balloon endoscopy (DBE) makes it possible to access to the small intestine for endoscopic interventions. We describe a successful case of early jejunum adenocarcinoma completely resected by endoscopic mucosal resection (EMR) using double-balloon endoscopy (DBE). Early diagnosis and EMR using new technologies such as CE and DBE may improve the recognition of this disease that, at present, has a poor prognosis.

  8. Role of double-balloon enteroscopy in malignant small bowel tumors

    PubMed Central

    Robles, Enrique Pérez-Cuadrado; Delgado, Pilar Esteban; Conesa, Paloma Bebia; Andrés, Blanca Martínez; Guggiana, Milivoj Franulic; Mateos, Eduardo Alcaraz; Caballero, Mariana Fernández; Agudo, José Luis Rodrigo; Martínez, Silvia Chacón; Latorre, Rafael; Soria, Federico; Gutiérrez, Juan Manuel Herrerías; Martínez, Enrique Pérez-Cuadrado

    2015-01-01

    AIM: To assess the double-balloon enteroscopy (DBE) role in malignant small bowel tumors (MSBT). METHODS: This is a retrospective descriptive study performed in a single center. All consecutive patients who underwent a DBE with final diagnosis of a malignant neoplasm from 2004 to 2014 in our referral center were included. Patient demographic and clinical pathological characteristics were recorded and reviewed. MSBT diagnosis was achieved either by DBE directed biopsy with multiple tissue sampling, endoscopic findings or histological analysis of surgical specimen. We have analyzed double-balloon enteroscopy impact in outcome and clinical course of these patients. RESULTS: Of 627 patients, 28 (4.5%) (mean age = 60 ± 17.3 years) underwent 30 procedures (25 anterograde, 5 retrograde) and were diagnosed of a malignant tumor. Patients presented with obscure gastrointestinal bleeding (n = 19, 67.9%), occlusion syndrome (n = 7, 25%) and diarrhea (n = 1, 3.6%). They were diagnosed by DBE biopsy (n = 18, 64.3%), histological analysis of surgical specimen (n = 7, 25%) and unequivocal endoscopic findings (n = 2, 7.1%). Gastrointestinal stromal tumor (n = 8, 28.6%), adenocarcinoma (n = 7, 25%), lymphoma (n = 4, 14.3%), neuroendocrine tumor (n = 4, 14.3%), metastatic (n = 3, 10.7%) and Kaposi sarcoma (n = 1, 3.6%) were identified. DBE modified outcome in 7 cases (25%), delaying or avoiding emergency surgery (n = 3), modifying surgery approach (n = 2) and indicating emergency SB partial resection instead of elective approach (n = 2). CONCLUSION: DBE may be critical in the management of MSBT providing additional information that may be decisive in the clinical course of these patients. PMID:26078833

  9. A case of lymphocytic-plasmacytic jejunitis diagnosed by double-balloon enteroscopy in a dog.

    PubMed

    Ayala, Ignacio; Latorre, Rafael; Soria, Federico; Carballo, Fernando; Lopez-Albors, Octavio; Buendia, Antonio J; Perez-Cuadrado, Enrique

    2011-01-01

    A 3 yr old male English setter dog was presented for evaluation of a 6-wk history of intermittent diarrhea. After standard gastroduodenoscopy and colonoscopy showed normal mucosa, double-balloon endoscopy (DBE) was used via both oral and anal approaches. Gross changes consistent with inflammation in the jejunum were seen, and biopsy specimens were obtained. Histologic analysis confirmed a diagnosis of lymphocytic-plasmacytic jejunitis. Clinical remission of the disease occurred after 3 mo of therapy with prednisone, metronidazole, and a novel protein diet. Use of DBE has not been previously reported in dogs with inflammatory bowel disease, and isolated lymphocytic-plasmacytic jejunitis has not been described. The described cases of intestinal inflammatory disease diagnosed by conventional endoscopy were related to pathologic changes in the duodenum, ileum or colon, but not the jejunum. The main advantage of the DBE technique allowed examination of portions of the small intestine (jejunum) that were not commonly accessible by standard endoscopic techniques, and permitted a minimally invasive collection of biopsy samples compared with surgical biopsy. This case highlights the need to consider using DBE in animals with gastrointestinal disorders, whose symptoms are not readily explained by routine tests, conventional endoscopy, and dietary or therapeutic trials.

  10. Metallic stent insertion with double-balloon endoscopy for malignant afferent loop obstruction

    PubMed Central

    Fujii, Masakuni; Ishiyama, Shuhei; Saito, Hiroaki; Ito, Mamoru; Fujiwara, Akiko; Niguma, Takefumi; Yoshioka, Masao; Shiode, Junji

    2015-01-01

    Progress in double-balloon endoscopy (DBE) has allowed for the diagnosis and treatment of disease in the postoperative bowel. For example, a short DBE, which has a 2.8 mm working channel and 152 cm working length, is useful for endoscopic retrograde cholangiopancreatography in bowel disease patients. However, afferent loop and Roux-limb obstruction, though rare, is caused by postoperative recurrence of biliary tract cancer with intractable complications. Most of the clinical findings involving these complications are relatively nonspecific and include abdominal pain, nausea, vomiting, fever, and obstructive jaundice. Treatments by surgery, percutaneous transhepatic biliary drainage, percutaneous enteral stent insertion, and endoscopic therapy have been reported. The general conditions of patients with these complications are poor due to cancer progression; therefore, a less invasive treatment is better. We report on the usefulness of metallic stent insertion using an overtube for afferent loop and Roux-limb obstruction caused by postoperative recurrence of biliary tract cancer under short DBE in two patients with complexly reconstructed intestines. PMID:26078835

  11. Comparison of Capsule Endoscopy Findings to Subsequent Double Balloon Enteroscopy: A Dual Center Experience

    PubMed Central

    Kalra, Amandeep S.; Walker, Andrew J.; Benson, Mark E.; Soni, Anurag; Guda, Nalini M.; Misha, Mehak; Gopal, Deepak V.

    2015-01-01

    Background. There has been a growing use of both capsule endoscopy (CE) and double balloon enteroscopy (DBE) to diagnose and treat patients with obscure gastrointestinal blood loss and suspected small bowel pathology. Aim. To compare and correlate sequential CE and DBE findings in a large series of patients at two tertiary level hospitals in Wisconsin. Methods. An IRB approved retrospective study of patients who underwent sequential CE and DBE, at two separate tertiary care academic centers from May 2007 to December 2011, was performed. Results. 116 patients were included in the study. The mean age ± SD was 66.6 ± 13.2 years. There were 56% males and 43.9% females. Measure of agreement between prior capsule and DBE findings was performed using kappa statistics, which gave kappa value of 0.396 with P < 0.001. Also contingency coefficient was calculated and was found to be 0.732 (P < 0.001). Conclusions. Our study showed good overall agreement between DBE and CE. Findings of angioectasia had maximum agreement of 69%. PMID:26420979

  12. Ileal polypoid lymphangiectasia bleeding diagnosed and treated by double balloon enteroscopy

    PubMed Central

    Park, Min Seon; Lee, Beom Jae; Gu, Dae Hoe; Pyo, Jeung-Hui; Kim, Kyeong Jin; Lee, Yun Ho; Joo, Moon Kyung; Park, Jong-Jae; Kim, Jae Seon; Bak, Young-Tae

    2013-01-01

    Intestinal lymphangiectasia is a rare disease characterized by focal or diffuse dilated enteric lymphatics with impaired lymph drainage. It causes protein-losing enteropathy and may lead to gastrointestinal bleeding. Commonly, lymphangiectasia presents as whitish spots or specks. To our knowledge, small bowel bleeding resulting from polypoid intestinal lymphangiectasia has not been reported. Here, we report a rare case of active bleeding from the small bowel caused by polypoid lymphangiectasia with a review of the relevant literature. An 80-year-old woman was hospitalized for melena. Esophagogastroduodenoscopy could not identify the source of bleeding. Subsequent colonoscopy showed fresh bloody material gushing from the small bowel. An abdominal-pelvic contrast-enhanced computed tomography scan did not reveal any abnormal findings. Video capsule endoscopy showed evidence of active and recent bleeding in the ileum. To localize the bleeding site, we performed double balloon enteroscopy by the anal approach. A small, bleeding, polypoid lesion was found in the distal ileum and was successfully removed using endoscopic snare electrocautery. PMID:24363538

  13. Ileal polypoid lymphangiectasia bleeding diagnosed and treated by double balloon enteroscopy.

    PubMed

    Park, Min Seon; Lee, Beom Jae; Gu, Dae Hoe; Pyo, Jeung-Hui; Kim, Kyeong Jin; Lee, Yun Ho; Joo, Moon Kyung; Park, Jong-Jae; Kim, Jae Seon; Bak, Young-Tae

    2013-12-07

    Intestinal lymphangiectasia is a rare disease characterized by focal or diffuse dilated enteric lymphatics with impaired lymph drainage. It causes protein-losing enteropathy and may lead to gastrointestinal bleeding. Commonly, lymphangiectasia presents as whitish spots or specks. To our knowledge, small bowel bleeding resulting from polypoid intestinal lymphangiectasia has not been reported. Here, we report a rare case of active bleeding from the small bowel caused by polypoid lymphangiectasia with a review of the relevant literature. An 80-year-old woman was hospitalized for melena. Esophagogastroduodenoscopy could not identify the source of bleeding. Subsequent colonoscopy showed fresh bloody material gushing from the small bowel. An abdominal-pelvic contrast-enhanced computed tomography scan did not reveal any abnormal findings. Video capsule endoscopy showed evidence of active and recent bleeding in the ileum. To localize the bleeding site, we performed double balloon enteroscopy by the anal approach. A small, bleeding, polypoid lesion was found in the distal ileum and was successfully removed using endoscopic snare electrocautery.

  14. Percutaneous Mitral Valve Dilatation: Single Balloon versus Double Balloon - A Finite Element Study

    SciTech Connect

    Schievano, Silvia; Kunzelman, Karyn; Nicosia, Mark; Cochran, R. P.; Einstein, Daniel R.; Khambadkone, Sachin; Bonheoffer, Philipp

    2009-01-01

    Background: Percutaneous mitral valve (MV) dilatation is performed with either a single balloon (SB) or double balloon (DB) technique. The aim of this study was to compare the two balloon system results using the finite element (FE) method. Methods and Results: An established FE model of the MV was modified by fusing the MV leaflet edges at commissure level to simulate a stenotic valve (orifice area=180mm2). A FE model of a 30mm SB (low-pressure, elastomeric balloon) and an 18mm DB system (high-pressure, non-elastic balloon) was created. Both SB and DB simulations resulted in splitting of the commissures and subsequent stenosis dilatation (final MV area=610mm2 and 560mm2 respectively). Stresses induced by the two balloon systems varied across the valve. At the end of inflation, SB showed higher stresses in the central part of the leaflets and at the commissures compared to DB simulation, which demonstrated a more uniform stress distribution. The higher stresses in the SB analysis were due to the mismatch of the round balloon shape with the oval mitral orifice. The commissural split was not easily accomplished with the SB due to its high compliance. The high pressure applied to the DB guaranteed the commissural split even when high forces were required to break the commissure welds. Conclusions: The FE model demonstrated that MV dilatation can be accomplished by both SB and DB techniques. However, the DB method resulted in higher probability of splitting of the fused commissures and less damage caused to the MV leaflets by overstretching.

  15. Double-balloon Enteroscopy: The results of a new experience in Iran

    PubMed Central

    Roushan, Nader; Froutan, Hossein; Taslimi, Reza; Kalani, Mohammad; Ganji, Azita; Darvish Moghaddam, Sodaif; Farahvash, Mohammad Jafar; Khazaeipour, Zahra

    2014-01-01

    Background: Approach to the small intestine has been difficult even with newer methods. Double-balloon enteroscopy (DBE) has been created for diagnostic and therapeutic interventions in diseases of the small intestine. Small intestinal diseases have different etiologies in each country. The DBE has been introduced in recent years in Iran. Our aim was to study the indications and results of DBE in some academic centers in Iran. Methods: Fifty-five patients with symptoms and signs related to small intestine without definitive diagnosis but with previous workup were enrolled in the study. The DBE was performed in three different medical universities in Iran. Results: The mean age of the patients that underwent the DBE was 47.2 ± 17.3 years. Abdominal pain (54.5%) and occult gastrointestinal bleeding (23.6%) were the most common presentations. Small bowel lesions were detected in 26 patients (47.3%); the most common lesions were ulcer (46.2%) and polyps (19.2%). Crohn’s disease (12.7%) was the commonest diagnosis found in DBE procedure. Patients presenting with abdominal pain orl ower hemoglobin level were more likely to be diagnosed (both p≤ 0.05). Small intestinal diseases were ultimately diagnosed in 47.3% of the patients. Twenty percent of the patients had another disease outside the small bowel. Conclusions: DBE is an effective and relatively safe diagnostic and therapeutic option for small bowel evaluations. Accurate selection of patients and more experience technicians and physicians will improve the efficacy of this procedure in Iran. PMID:25250264

  16. [Double-balloon angioplasty of pulmonary venous drainage obstruction after the Senning procedure in transposition of the great vessels].

    PubMed

    Benito Bartolomé, F; Sánchez Fernández-Bernal, C

    1999-10-01

    A six and half-year old boy with Senning operation for transposition of the great arteries, showed recurrent atrial flutter and obstruction of the pulmonary venous atrium from the early postoperative period. By Doppler examination a peak gradient of 13 mmHg at the isthmus level was recorded in the pulmonary venous atrium. A successful double-balloon dilatation of stenotic area was performed via a retrograde, transaortic, approach through angioplasty. Six months after the procedure the enlargement of the stenosis persists, and the patient is clinically asymptomatic and arrhythmia-free without medication.

  17. Impact of a Newly Developed Short Double-Balloon Enteroscope on Stent Placement in Patients with Surgically Altered Anatomies

    PubMed Central

    Tsutsumi, Koichiro; Kato, Hironari; Okada, Hiroyuki

    2017-01-01

    A newly developed short double-balloon enteroscope with a working channel enlarged to a diameter of 3.2 mm is a novel innovation in stent placement for patients with surgically altered anatomies. Herein, we report three patients in whom this new scope contributed to an efficient technique and ideal treatment. In the first case, the double guidewire technique was efficient and effective for multiple stent placements. In the second case, covered self-expandable metal stent (SEMS) placement, which is the standard treatment for malignant biliary obstruction, could be performed in a technologically sound and safe manner. In the third case, SEMS placement was performed as palliative treatment for malignant afferent-loop obstruction; this procedure could be performed soundly and safely using the through-the-scope technique. The wider working channel of this new scope also facilitates a smoother accessory insertion and high suction performance, which reduces procedure time and stress on endoscopists. Furthermore, this new scope, which has advanced force transmission, adaptive bending, and a smaller turning radius, is expected to be highly successful in both diagnosis and therapy for various digestive diseases in patients with surgically altered anatomies. PMID:28208009

  18. A case of a ruptured submucosal aneurysm of the small intestine identified using double-balloon enteroscopy.

    PubMed

    Chiba, Hirofumi; Endo, Katsuya; Fujishima, Fumiyoshi; Ohtsuka, Hideo; Naitoh, Takeshi; Kuroha, Masatake; Kimura, Tomoya; Shiga, Hisashi; Kakuta, Yoichi; Kinouchi, Yoshitaka; Unno, Michiaki; Shimosegawa, Tooru

    2016-04-01

    A 47-year-old woman was admitted to our hospital urgently with sudden-onset hematochezia. She was temporarily in a state of hemorrhagic shock. As we strongly suspected bleeding from the small intestine, peroral double-balloon enteroscopy was performed, and indicated a 2.0-cm diameter hemispheric elevated lesion in the jejunum. Moreover, a blood clot was observed at the top of the protrusion. The site was marked by injecting India ink, without taking a biopsy specimen, to avoid further hemorrhaging. Subsequently, laparoscopic partial small bowel resection was performed. On histopathological examination, the lesion was found to be a sac-like submucosal arterial aneurysm, with a diameter of 3.5 mm, comprising several small abnormal arteries. The final diagnosis was a ruptured submucosal aneurysm of the small intestine. Ruptured submucosal aneurysms are very rarely observed in the small intestine. Only a few reports have described their endoscopic findings. Our experience indicates that small bowel enteroscopy may be useful for managing ruptured submucosal aneurysms of the small intestine.

  19. Double-Balloon Endoscopy in Overt and Occult Small Bowel Bleeding: Results, Complications, and Correlation with Prior Videocapsule Endoscopy in a Tertiary Referral Center

    PubMed Central

    Hermans, Carlijn; Stronkhorst, Arnold; Tjhie-Wensing, Annemarie; Kamphuis, Jan; van Balkom, Bas; Dahlmans, Rob; Gilissen, Lennard

    2017-01-01

    Background/Aims Videocapsule endoscopy (VCE) and double-balloon endoscopy (DBE) allow deep exploration in patients with suspected small bowel pathology. VCE is often performed as an initial small bowel examination to explore whether an intervention by DBE is indicated and to determine insertion route. The study aim was to evaluate the correlation between DBE and VCE in patients with obscure or overt bleeding or anemia, as well as intervention frequency, and complications. Methods Retrospective observational study. Results DBE procedures (n=205) showed small bowel lesions in 64% cases. Antegrade DBE showed positive results in 79% cases, mostly angiodysplasias (63%). Retrograde DBE showed positive results in 22% cases. An intervention was performed in 64% of DBE procedures. The major complication rate was 0.5%, which was one case of perforation. Pancreatitis did not occur. The overall diagnostic agreement was 66% among the 134 DBEs with preceded VCE. Conclusions In cases of overt or occult bleeding or anemia, DBE was positive in 64%, with only a few complications. Positive correlation was 66% among initially performed VCEs and DBEs. Owing to the time-consuming and invasive character of DBE, performing VCE before DBE might still be clinically relevant. PMID:28076941

  20. A comparative evaluation of treatment methods for bile duct stones after hepaticojejunostomy between percutaneous transhepatic cholangioscopy and peroral, short double-balloon enteroscopy

    PubMed Central

    Tsutsumi, Koichiro; Kato, Hironari; Yabe, Shuntaro; Mizukawa, Sho; Seki, Hiroyuki; Akimoto, Yutaka; Uchida, Daisuke; Matsumoto, Kazuyuki; Tomoda, Takeshi; Yamamoto, Naoki; Horiguchi, Shigeru; Kawamoto, Hirofumi; Okada, Hiroyuki

    2016-01-01

    Background: Bile duct stones after hepaticojejunostomy are considered a troublesome adverse event. Although percutaneous transhepatic procedures using a cholangioscopy is performed to treat these bile duct stones, a peroral endoscopic procedure using a short, double-balloon enteroscope (sDBE) is an alternative. This study aimed to compare the immediate and long-term outcomes of both treatments for bile duct stones in patients who underwent prior hepaticojejunostomy. Methods: Between October 2001 and May 2013, 40 consecutive patients were treated for bile duct stones after hepaticojejunostomy at a tertiary care hospital. Initial success with biliary access, biliary intervention-related technical success, clinical success, adverse events, hospitalization duration, and stone-free survival were retrospectively evaluated. Results: The initial success rates for biliary access were 100% (8/8) with percutaneous transhepatic cholangioscopy (PTCS) and 91% (29/32) with sDBE. In three patients in whom biliary access during initial sDBE failed, successful access with subsequent PTCS was achieved, and biliary intervention-related technical success and clinical success were eventually achieved in all 40 patients. The rate of adverse events was significantly lower with sDBE than with PTCS (10% versus 45%; p = 0.025). The median hospitalization duration for complete stone clearance was significantly shorter with sDBE than with PTCS (10 versus 35 days; p < 0.001). During the median 7.2 year or 3.1 year follow up, the probabilities of being stone-free at 1, 2, and 3 years were 100%, 73%, and 64% for PTCS and 85%, 65%, and 59% for sDBE, respectively (p = 0.919). Conclusions: sDBE was useful, with few adverse events and short hospitalization; therefore, experienced endoscopists can consider it as first-line treatment for bile duct stones in patients with prior hepaticojejunostomy. PMID:28286559

  1. Double-balloon enteroscopy for ERCP in patients with Billroth II anatomy: results of a large series of papillary large-balloon dilation for biliary stone removal

    PubMed Central

    Cheng, Chi-Liang; Liu, Nai-Jen; Tang, Jui-Hsiang; Yu, Ming-Chin; Tsui, Yi-Ning; Hsu, Fang-Yu; Lee, Ching-Song; Lin, Cheng-Hui

    2015-01-01

    Background and study aims: Data on double-balloon enteroscopy (DBE)-assisted endoscopic retrograde cholangiopancreatogrphy (ERCP) in patients with Billroth II gastrectomy and the use of endoscopic papillary large-balloon dilation (EPLBD) for the removal of common bile duct stones in Billroth II anatomy are limited. The aims of the study were to evaluate the success of DBE-assisted ERCP in patients with Billroth II gastrectomy and examine the efficacy of EPLBD ( ≥ 10 mm) for the removal of common bile duct stones. Patients and methods: A total of 77 patients with Billroth II gastrectomy in whom standard ERCP had failed underwent DBE-assisted ERCP. DBE success was defined as visualizing the papilla and ERCP success as completing the intended intervention. The clinical results of EPLBD for the removal of common bile duct stones were analyzed. Results: DBE was successful in 73 of 77 patients (95 %), and ERCP success was achieved in 67 of these 73 (92 %). Therefore, the rate of successful DBE-assisted ERCP was 87 % (67 of a total of 77 patients). The reasons for ERCP failure (n = 10) included tumor obstruction (n = 2), adhesion obstruction (n = 2), failed cannulation (n = 3), failed stone removal (n = 2), and bowel perforation (n = 1). Overall DBE-assisted ERCP complications occurred in 5 of 77 patients (6.5 %). A total of 48 patients (34 male, mean age 75.5 years) with common bile duct stones underwent EPLBD. Complete stone removal in the first session was accomplished in 36 patients (75 %); mechanical lithotripsy was required in 1 patient. EPLBD-related mild perforation occurred in 2 patients (4 %). No acute pancreatitis occurred. Conclusions: DBE permits therapeutic ERCP in patients who have a difficult Billroth II gastrectomy with a high success rate and acceptable complication rates. EPLBD is effective and safe for the removal of common bile duct stones in patients with Billroth II anatomy. PMID:26171434

  2. A four lumen screwing device for multiparametric brain monitoring.

    PubMed

    Feuerstein, T H; Langemann, H; Gratzl, O; Mendelowitsch, A

    2000-01-01

    We describe multiparametric monitoring in severe head trauma using a new screwing device. Our aim was to create a screw which would make the implantation of the probes and thus multiparametric monitoring easier. The new screw allows us to implant 3 probes (microdialysis, Paratrend and an intracranial pressure device) through one burr hole. The screw has four channels, the fourth being for ventricular drainage. We monitored 13 patients with severe head trauma (GCS = 3-8) for up to 7 days. Brain tissue pO2, pCO2, pH, and temperature were measured on-line with the Paratrend 7 machine. The microdialytic parameters glucose, lactate, pyruvate and glutamate were determined semi on-line with a CMA 600 enzymatic analyser. There were no complications in any of the patients that could be ascribed to the screw.

  3. Original Misunderstanding

    ERIC Educational Resources Information Center

    Holtzman, Alexander

    2009-01-01

    Humorist Josh Billings quipped, "About the most originality that any writer can hope to achieve honestly is to steal with good judgment." Billings was harsh in his view of originality, but his critique reveals a tension faced by students every time they write a history paper. Research is the essence of any history paper. Especially in high school,…

  4. Originator dynamics

    PubMed Central

    Manapat, Michael; Ohtsuki, Hisashi; Bürger, Reinhard; Nowak, Martin A.

    2009-01-01

    We study the origin of evolution. Evolution is based on replication, mutation, and selection. But how does evolution begin? When do chemical kinetics turn into evolutionary dynamics? We propose “prelife” and “prevolution” as the logical precursors of life and evolution. Prelife generates sequences of variable length. Prelife is a generative chemistry that proliferates information and produces diversity without replication. The resulting “prevolutionary dynamics” have mutation and selection. We propose an equation that allows us to investigate the origin of evolution. In one limit, this “originator equation” gives the classical selection equation. In the other limit, we obtain “prelife.” There is competition between life and prelife and there can be selection for or against replication. Simple prelife equations with uniform rate constants have the property that longer sequences are exponentially less frequent than shorter ones. But replication can reverse such an ordering. As the replication rate increases, some longer sequences can become more frequent than shorter ones. Thus, replication can lead to “reversals” in the equilibrium portraits. We study these reversals, which mark the transition from prelife to life in our model. If the replication potential exceeds a critical value, then life replicates into existence. PMID:18996397

  5. [Origin of biosphere].

    PubMed

    Levchenko, V F; Starobogatov, Ia I

    2010-01-01

    Concepts of origin of life on the planet are briefly considered. The problem of origin of biosphere is discussed, with a suggestion that the origin of living organisms and biosphere are two aspects of the same process. There is put forward a hypothesis of embryosphere--the primary medium, in which preorganisms could appear. The ecosystemic approach to origin of life poses a question about sources of the matter and energy used by the primary life as well as about causes of the biochemical unity that exists in all Earth organisms.

  6. Chemical Origins of Life

    ERIC Educational Resources Information Center

    Fox, J. Lawrence

    1972-01-01

    Reviews ideas and evidence bearing on the origin of life. Shows that evidence to support modifications of Oparin's theories of the origin of biological constituents from inorganic materials is accumulating, and that the necessary components are readily obtained from the simple gases found in the universe. (AL)

  7. The Moon's Origin.

    ERIC Educational Resources Information Center

    Cadogan, Peter

    1983-01-01

    Presents findings and conclusions about the origin of the moon, favoring the capture hypothesis of lunar origin. Advantage of the hypothesis is that it allows the moon to have been formed elsewhere, specifically in a hotter part of the solar nebula, accounting for chemical differences between earth and moon. (JN)

  8. Originalism in the Classroom

    ERIC Educational Resources Information Center

    Forte, David F.

    2011-01-01

    In this article, the author provides a detailed legal history of originalism and investigates whether, and to what extent, originalism is a part of law school teaching on the Constitution. He shares the results of an examination of the leading constitutional law textbooks used in the top fifty law schools and a selection of responses gathered from…

  9. Origins of organic geochemistry

    USGS Publications Warehouse

    Kvenvolden, K.A.

    2008-01-01

    When organic geochemistry actually began as a recognized geoscience is a matter of definition and perspective. Constraints on its beginning are placed by the historical development of its parent disciplines, geology and organic chemistry. These disciplines originated independently and developed in parallel, starting in the latter half of the 18th century and flourishing thereafter into the 21st century. Organic geochemistry began sometime between 1860 and 1983; I argue that 1930 is the best year to mark its origin.

  10. Back to the Origin

    PubMed Central

    Evertts, Adam G.

    2012-01-01

    In bacteria, replication is a carefully orchestrated event that unfolds the same way for each bacterium and each cell division. The process of DNA replication in bacteria optimizes cell growth and coordinates high levels of simultaneous replication and transcription. In metazoans, the organization of replication is more enigmatic. The lack of a specific sequence that defines origins of replication has, until recently, severely limited our ability to define the organizing principles of DNA replication. This question is of particular importance as emerging data suggest that replication stress is an important contributor to inherited genetic damage and the genomic instability in tumors. We consider here the replication program in several different organisms including recent genome-wide analyses of replication origins in humans. We review recent studies on the role of cytosine methylation in replication origins, the role of transcriptional looping and gene gating in DNA replication, and the role of chromatin’s 3-dimensional structure in DNA replication. We use these new findings to consider several questions surrounding DNA replication in metazoans: How are origins selected? What is the relationship between replication and transcription? How do checkpoints inhibit origin firing? Why are there early and late firing origins? We then discuss whether oncogenes promote cancer through a role in DNA replication and whether errors in DNA replication are important contributors to the genomic alterations and gene fusion events observed in cancer. We conclude with some important areas for future experimentation. PMID:23634256

  11. [Hypotension from endocrine origin].

    PubMed

    Vantyghem, Marie-Christine; Douillard, Claire; Balavoine, Anne-Sophie

    2012-11-01

    Hypotension is defined by a low blood pressure either permanently or only in upright posture (orthostatic hypotension). In contrast to hypertension, there is no threshold defining hypotension. The occurrence of symptoms for systolic and diastolic measurements respectively below 90 and 60 mm Hg establishes the diagnosis. Every acute hypotensive event should suggest shock, adrenal failure or an iatrogenic cause. Chronic hypotension from endocrine origin may be linked to adrenal failure from adrenal or central origin, isolated hypoaldosteronism, pseudohypoaldosteronism, pheochromocytoma, neuro-endocrine tumors (carcinoïd syndrome) or diabetic dysautonomia. Hypotension related to hypoaldosteronism associates low blood sodium and above all high blood potassium levels. They are generally classified according to their primary (hyperreninism) or secondary (hyporeninism) adrenal origin. Isolated primary hypoaldosteronisms are rare in adults (intensive care unit, selective injury of the glomerulosa area) and in children (aldosterone synthase deficiency). Isolated secondary hypoaldosteronism is related to mellitus diabetes complicated with dysautonomia, kidney failure, age, iatrogenic factors, and HIV infections. In both cases, they can be associated to glucocorticoid insufficiency from primary adrenal origin (adrenal failure of various origins with hyperreninism, among which congenital 21 hydroxylase deficiency with salt loss) or from central origin (hypopituitarism with hypo-reninism). Pseudohypoaldosteronisms are linked to congenital (type 1 pseudohypoaldosteronism) or acquired states of resistance to aldosterone. Acquired salt losses from enteric (total colectomy with ileostomy) or renal (interstitial nephropathy, Bartter and Gitelman syndromes…) origin might be responsible for hypotension and are associated with hyperreninism-hyperaldosteronism. Hypotension is a rare manifestation of pheochromocytomas, especially during surgical removal when the patient has not been

  12. Origin of life

    NASA Astrophysics Data System (ADS)

    Ehrenfreund, P.; Cleaves, H. J.

    2003-10-01

    Deciphering the origin of life requires some knowledge of the early planetary environment. Unfortunately, we lack definitive evidence of the atmospheric composition, surface temperature, oceanic pH, and other environmental conditions that may have been important for the appearance of the first living systems on Earth. The rock remnants of the early Archean are extremely scarce and most of the record has been lost. The first indications of life from carbon inclusions in rocks and the oldest fossil record are currently under debate but there is a consensus that life started during the first billion years after the Earth formed. Life as we know it is a chemical phenomenon. The chemistry that could have produced self-organizing systems is the central problem in the origin of life. There are several competing theories for how this chemistry may have arisen. In spite of their diversity, proposals for a prebiotic "soup", for the role of submarine hydrothermal vents, or for the extraterrestrial origin of organic compounds have as a common background assumption the idea that abiotic organic compounds were necessary for the emergence of life. It is possible that a combination of these sources - exogenous and endogenous - contributed building blocks for the origin of life on Earth. In this paper we provide a review of the main ideas on the origin of life from the astrobiological perspective and discuss the probability of life on extrasolar planets.

  13. Origins Space Telescope

    NASA Astrophysics Data System (ADS)

    Cooray, Asantha R.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its spectrographs will enable 3D surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu. I will summarize the OST STDT, mission design and instruments, key science drivers, and the study plan over the next two years.

  14. Building, north side (original front), detail of original entrance. Camera ...

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

    Building, north side (original front), detail of original entrance. Camera facing south - Naval Supply Center, Broadway Complex, Administration Storehouse, 911 West Broadway, San Diego, San Diego County, CA

  15. Originality and Creativity.

    ERIC Educational Resources Information Center

    Tan, Shaun

    This paper discusses the creative process of one author, a professional author/illustrator of picture books. The paper muses about the meaning of creativity and originality and states inspiration has to do with careful research and looking for a challenge. Creativity is about testing one proposition against another and seeing how things combine…

  16. Conscientiousness: Origins in Childhood?

    ERIC Educational Resources Information Center

    Eisenberg, Nancy; Duckworth, Angela L.; Spinrad, Tracy L.; Valiente, Carlos

    2014-01-01

    In this review, we evaluate developmental and personality research with the aim of determining whether the personality trait of conscientiousness can be identified in children and adolescents. After concluding that conscientiousness does emerge in childhood, we discuss the developmental origins of conscientiousness with a specific focus on…

  17. The Origins of Writing.

    ERIC Educational Resources Information Center

    Schmandt-Besserat, Denise

    Writing appears to have originated from a modest system of counters or tokens used to keep track of economic goods and transactions. This system of recording appeared in 8000 B. C. in Mesopotamia, or what is now Iraq. The tokens' consistency in shape and size during the next 4,000 years attests to the stability of the agricultural economy and way…

  18. The Origins of Mass

    SciTech Connect

    Lincoln, Don

    2014-07-30

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  19. The Origin of Gravitation

    NASA Astrophysics Data System (ADS)

    Zheng, Sheng Ming

    2012-10-01

    In the natural world, people have discovered four kinds of forces: electromagnetic force, gravitation, weak force, and strong force. Although the gravitation has been discovered more than three hundred years, its mechanism of origin is unclear until today. While investigating the origin of gravitation, I do some experiments discover the moving photons produce gravitation. This discovery shows the origin of gravitation. Meanwhile I do some experiments discover the light interference fringes are produced by the gravitation: my discovery demonstrate light is a particle, but is not a wave-particle duality. Furthermore, applications of this discovery to other moving particles show a similar effect. In a word: the micro particle moving produce gravitation and electromagnetic force. Then I do quantity experiment get a general formula: Reveal the essence of gravitational mass and the essence of electric charge; reveal the origin of gravitation and the essence of matter wave. Along this way, I unify the gravitation and electromagnetic force. Namely I find a natural law that from atomic world to star world play in moving track. See website: https://www.lap-publishing.com/catalog/details/store/gb/book/978-3-8473-2658-8/mechanism-of-interaction-in-moving-matter

  20. The Origins of Mass

    ScienceCinema

    Lincoln, Don

    2016-07-12

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  1. Origins of Coordinate Searching.

    ERIC Educational Resources Information Center

    Kilgour, Frederick G.

    1997-01-01

    Reviews the origins of post-coordinate searching and emphasizes that the focal point should be on the searcher, not on the item being indexed. Highlights include the history of the term information retrieval; edge notched punch cards; the "peek-a-boo" system; the Uniterm system; and using computers to search for information. (LRW)

  2. Cosmic Origin of Quantization

    NASA Astrophysics Data System (ADS)

    Calogero, Francesco

    An estimate is presented of the angular momentum associated with the stochastic cosmic tremor, which has been hypothesized to be caused by universal gravitation and by the granularity of matter, and to be itself the cause of quantization ("cosmic origin of quantization"). If that universal tremor has the spatial coherence which is instrumental in order that the estimated action associated with it have the order of magnitude of Planck's constant h, then the estimated order of magnitude of the angular momentum associated with it also has the same value. We moreover indicate how these findings (originally based on a simplified model of the Universe, as being made up only of particles having the nucleon mass) are affected (in fact, essentially unaffected) by the possible presence in the mass of the Universe of a large component made up of particles much lighter than nucleons ("dark", or "missing", mass).

  3. Toothache of cardiac origin.

    PubMed

    Kreiner, M; Okeson, J P

    1999-01-01

    Pain referred to the orofacial structures can sometimes be a diagnostic challenge for the clinician. In some instances, a patient may complain of tooth pain that is completely unrelated to any dental source. This poses a diagnostic and therapeutic problem for the dentist. Cardiac pain most commonly radiates to the left arm, shoulder, neck, and face. In rare instances, angina pectoris may present as dental pain. When this occurs, an improper diagnosis frequently leads to unnecessary dental treatment or, more significantly, a delay of proper treatment. This delay may result in the patient experiencing an acute myocardial infarction. It is the dentist's responsibility to establish a proper diagnosis so that the treatment will be directed toward the source of pain and not to the site of pain. This article reviews the literature concerning referred pain of cardiac origin and presents a case report of toothache of cardiac origin.

  4. Bioenergetics and Life's Origins

    PubMed Central

    Deamer, David; Weber, Arthur L.

    2010-01-01

    Bioenergetics is central to our understanding of living systems, yet has attracted relatively little attention in origins of life research. This article focuses on energy resources available to drive primitive metabolism and the synthesis of polymers that could be incorporated into molecular systems having properties associated with the living state. The compartmented systems are referred to as protocells, each different from all the rest and representing a kind of natural experiment. The origin of life was marked when a rare few protocells happened to have the ability to capture energy from the environment to initiate catalyzed heterotrophic growth directed by heritable genetic information in the polymers. This article examines potential sources of energy available to protocells, and mechanisms by which the energy could be used to drive polymer synthesis. PMID:20182625

  5. Origin of Life

    NASA Astrophysics Data System (ADS)

    Lal, Ashwini Kumar

    2008-10-01

    The evolution of life has been a big enigma despite rapid advancements in the field of astrobiology, microbiology and genetics in recent years. The answer to this puzzle is as mindboggling as the riddle relating to evolution of the universe itself. Despite the fact that panspermia has gained considerable support as a viable explanation for origin of life on the earth and elsewhere in the universe, the issue, however, remains far from a tangible solution. This paper examines the various prevailing hypotheses regarding origin of life-like abiogenesis, RNA world, iron-sulphur world and panspermia, and concludes that delivery of life-bearing organic molecules by the comets in the early epoch of the earth alone possibly was not responsible for kick-starting the process of evolution of life on our planet.

  6. Endosymbionts and mitochondrial origins

    NASA Technical Reports Server (NTRS)

    Woese, C. R.

    1977-01-01

    The possibility is put forth that the mitochondrion did not originate from an endosymbiosis 1-2 billion years ago involving an aerobic bacterium. Rather, it arose by endosymbiosis in a much earlier anaerobic period and was initially a photosynthetic organelle analogous to the modern chloroplast. This suggestion arises from a reconsideration of the nature of endosymbiosis. It explains the remarkable diversity in mitochondrial information storage and processing systems.

  7. Origin of the Metazoa.

    PubMed Central

    Lake, J A

    1990-01-01

    The origin of the multicellular animals has been investigated by rate invariant analysis of 18S rRNA sequences. These analyses indicate that (i) the Metazoa is a monophyletic taxon; (ii) the Deuterostomia is a monophyletic taxon; (iii) the Annelida-Mollusca lineage is the sister group of an arthropod subgroup; and (iv) the last common ancestor of the Annelida-Mollusca lineage is most parsimoniously derived from a segmented, hemocoelic ancestor with an open circulatory system. PMID:2300560

  8. Origins of magnetospheric plasma

    SciTech Connect

    Moore, T.E. )

    1991-01-01

    A review is given of recent (1987-1990) progress in understanding of the origins of plasmas in the earth's magnetosphere. In counterpoint to the early supposition that geomagnetic phenomena are produced by energetic plasmas of solar origin, 1987 saw the publication of a provocative argument that accelerated ionospheric plasma could supply all magnetospheric auroral and ring current particles. Significant new developments of existing data sets, as well as the establishment of entirely new data sets, have improved the ability to identify plasma source regions and to track plasma through the magnetospheric system of boundary layers and reservoirs. These developments suggest that the boundary between ionospheric and solar plasmas, once taken to lie at the plasmapause, actually lies much nearer to the magnetopause. Defining this boundary as the surface where solar wind and ionosphere contribute equally to the plasma, it is referred to herein as the 'geopause'. It is now well established that the infusion of ionospheric O(+) plays a major role in the storm-time distention of the magnetotail and inflation of the inner magnetosphere. After more than two decades of observation and debate, the question remains whether magnetosheric are protons of solar or terrestrial origin. 161 refs.

  9. Origin of Tektites.

    PubMed

    O'keefe, J A; Shute, B E

    1963-03-29

    A comet of the size recently postulated by H. C. Urey would leave a large crater. It is shown, from aerodynamic theory, from observations of distribution around terrestrial impact craters, and from experimental nuclear explosions, that the observed distribution of tektites cannot be the result of impact on the earth, whether cometary or meteoritic. It is further shown, from aerodynamic theory, from observation of a meteor shower, and from study of the breakup of artificial satellites, that the distribution of tektites can be accounted for as a result of fusion stripping of a satellite, as originally suggested by Suess.

  10. The Origin of Echocardiography

    PubMed Central

    Singh, Siddharth; Goyal, Abha

    2007-01-01

    The original description of M-mode echocardiography in 1953, by Inge Edler (1911–2001) and his physicist friend Hellmuth Hertz, marked the beginning of a new diagnostic noninvasive technique. Edler used this technique primarily for the preoperative study of mitral stenosis and diagnosis of mitral regurgitation. His work was carried forward by cardiologists all over the world, who developed Doppler, 2-dimensional, contrast, and transesophageal echocardiography. These are now standard in cardiologic examinations. Edler also influenced neurologists and obstetricians at Lund University (Sweden) to use ultrasound in their fields. For his landmark discovery, Edler is recognized as the “Father of Echocardiography.” PMID:18172524

  11. Origin of earth's moon

    NASA Technical Reports Server (NTRS)

    Wood, J. A.

    1977-01-01

    The major geochemical properties of the moon are briefly considered along with the significant facts of the moon's geologic history, and then the three current hypotheses regarding the moon's origin, namely, fission, capture, and binary accretion, are reviewed. The individual merits and improbabilities associated with each mechanism are taken into consideration. Special attention is given to the binary accretion model as the most promising one. In the variants of this model, of crucial importance is the nature of the more general hypothesis assumed for planetary formation from the solar nebula. The two main models differ considerably in the amount of chemical fractionation they allow to accompany planetary formation.

  12. Molecular origin of friction

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Zhang, Tao; Hu, Yuanzhong

    2004-01-01

    The wearless friction originating from molecular interactions has been discussed in this paper. We find that the frictional properties are closely related to the structural match of two surfaces in relative motion. For the surfaces with incommensurate structure and week inter-surface interaction, zero static and kinetic friction can be achieved. In a sliding considered as in a quasi-static state, the energy dissipation initiates when interfacial particles move in a discontinuous fashion, which gives rise to a finite kinetic friction. The state of superlubricity is a result of computer simulations, but the prediction will encourage people to look for a technical approach to realizing the state of super low friction.

  13. The Origins of Neuroticism.

    PubMed

    Barlow, David H; Ellard, Kristen K; Sauer-Zavala, Shannon; Bullis, Jacqueline R; Carl, Jenna R

    2014-09-01

    In this article, we provide a fresh perspective on the developmental origins of neuroticism--a dimension of temperament marked by elevated stress reactivity resulting in the frequent experience of negative emotions. This negative affectivity is accompanied by a pervasive perception that the world is a dangerous and threatening place, along with beliefs about one's inability to manage or cope with challenging events. Historically, neuroticism has been viewed as a stable, genetically based trait. However, recent understanding of ongoing gene-environment interactions that occur throughout the life span suggests there may be a more complex and dynamic etiology. Thus, the purpose of this article is to offer a theory for understanding the development of neuroticism that integrates genetic, neurobiological, and environmental contributions to this trait. Given the strong correlation between neuroticism and the development of negative health outcomes--most notably, the full range of anxiety and mood disorders--an enhanced understanding of how neuroticism originates has implications for the treatment and prevention of a broad range of pathologies and, perhaps, even for the prevention of neuroticism itself.

  14. Origins of Bladder Cancer.

    PubMed

    Czerniak, Bogdan; Dinney, Colin; McConkey, David

    2016-05-23

    Bladder cancer, one of the most frequently occurring human cancers, develops via two tracks referred to as papillary and nonpapillary that correspond to clinically different forms of the disease. Most bladder cancers are chemically induced, with tobacco smoking being the leading risk factor. Recent advances in bladder cancer research have enhanced our understanding of the origin of this disease from urothelial progenitor cells via field effects along papillary/luminal and nonpapillary/basal pathways. Evident from the outset of the disease, the diversity of the luminal and basal pathways, together with cell lineage tracing studies, postulates the origin of molecularly distinct subtypes from different uroprogenitor cells. The molecular mechanisms initiating field effects involve a new class of genes referred to as forerunner (FR) genes that generally map around major tumor suppressors such as RB1. These genes are silenced, predominantly by hypermethylation and less frequently by mutations, and drive the expansion of intraurothelial preneoplastic cells. Different FR genes are involved in various molecular subtypes of bladder cancer and they sensitize the uroprogenitor cells to the development of luminal and basal bladder cancers in animal models. In human bladder cancer, luminal and basal forms have dissimilar clinical behavior and response to conventional and targeted chemotherapeutic manipulations. These new research developments hold the promise of expanding our armamentarium of diagnostic and treatment options for patients with bladder cancer and improving our ability to select patients most likely to respond to a specific therapy.

  15. The origin of Neandertals

    PubMed Central

    Hublin, J. J.

    2009-01-01

    Western Eurasia yielded a rich Middle (MP) and Late Pleistocene (LP) fossil record documenting the evolution of the Neandertals that can be analyzed in light of recently acquired paleogenetical data, an abundance of archeological evidence, and a well-known environmental context. Their origin likely relates to an episode of recolonization of Western Eurasia by hominins of African origin carrying the Acheulean technology into Europe around 600 ka. An enhancement of both glacial and interglacial phases may have played a crucial role in this event, as well as in the subsequent evolutionary history of the Western Eurasian populations. In addition to climatic adaptations and an increase in encephalization, genetic drift seems to have played a major role in their evolution. To date, a clear speciation event is not documented, and the most likely scenario for the fixation of Neandertal characteristics seems to be an accretion of features along the second half of the MP. Although a separation time for the African and Eurasian populations is difficult to determine, it certainly predates OIS 11 as phenotypic Neandertal features are documented as far back as and possibly before this time. It is proposed to use the term “Homo rhodesiensis” to designate the large-brained hominins ancestral to H. sapiens in Africa and at the root of the Neandertals in Europe, and to use the term “Homo neanderthalensis” to designate all of the specimens carrying derived metrical or non-metrical features used in the definition of the LP Neandertals. PMID:19805257

  16. Origin of Waldenstrom's macroglobulinaemia.

    PubMed

    García-Sanz, Ramón; Jiménez, Cristina; Puig, Noemí; Paiva, Bruno; Gutiérrez, Norma C; Rodríguez-Otero, Paula; Almeida, Julia; San Miguel, Jesús; Orfão, Alberto; González, Marcos; Pérez-Andrés, Martín

    2016-06-01

    Waldenstrom's macroglobulinaemia (WM) is an MYD88(L265P)-mutated lymphoplasmacytic lymphoma that invades bone marrow and secretes monoclonal immunoglobulin M (IgM). WM cells are usually unable to undergo class switch recombination, and have mutated IGHV, with a typical immunophenotype CD19(+)/CD22(low+)/CD23(-)/CD25(+)/CD27(+)/CD45(+)/CD38(low+)/SmIgM(+) (negative for CD5, CD10, CD11c, CD103). This immunophenotype matches memory B cells (smIgM(-/+)/CD10(-)/CD19(+)/CD20(+)/CD27(+)/CD38(low+)/CD45(+)), representing 30% of B cells in the blood. Fifty percent of them have not undergone class switch recombination and are IgM(+). These cells have suffered somatic hypermutation as WM cells. Genetic abnormalities do not abrogate the capacity to progress to plasma cells that usually belong to the clonal WM compartment, with a normal immunophenotype and functional characteristics. However, some WM cells are CD27(-), MYD88(WT), without somatic hypermutation, or with class switch recombination capable of reactivation. Thus, most data support a B-memory-cell origin for WM, but a small fraction of cases may have a different origin.

  17. The Origins of Options

    PubMed Central

    Smaldino, Paul E.; Richerson, Peter J.

    2012-01-01

    Most research on decision making has focused on how human or animal decision makers choose between two or more options, posed in advance by the researchers. The mechanisms by which options are generated for most decisions, however, are not well understood. Models of sequential search have examined the trade-off between continued exploration and choosing one’s current best option, but still cannot explain the processes by which new options are generated. We argue that understanding the origins of options is a crucial but untapped area for decision making research. We explore a number of factors which influence the generation of options, which fall broadly into two categories: psycho-biological and socio-cultural. The former category includes factors such as perceptual biases and associative memory networks. The latter category relies on the incredible human capacity for culture and social learning, which doubtless shape not only our choices but the options available for choice. Our intention is to start a discussion that brings us closer toward understanding the origins of options. PMID:22514515

  18. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. View of sawmill after earthquake of 1898. - Mare Island Naval Shipyard, East of Nave Drive, Vallejo, Solano County, CA

  19. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. View of waterfront during World War II; N.D. - Mare Island Naval Shipyard, East of Nave Drive, Vallejo, Solano County, CA

  20. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. View of Franklin D. Roosevelt walking past old Marine Corps Barracks; 1913. - Mare Island Naval Shipyard, East of Nave Drive, Vallejo, Solano County, CA

  1. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. View of building 133 being moved; 1933. - Mare Island Naval Shipyard, East of Nave Drive, Vallejo, Solano County, CA

  2. Photograph of original drawing (original in possession of National Passenger ...

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

    Photograph of original drawing (original in possession of National Passenger Railroad Corporation). Canopy Plans, Sections, and Details (n.d.) - North Philadelphia Station, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

  3. 18. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    18. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) PLANS AND SECTIONS, MECHANICAL EQUIPMENT-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  4. 15. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    15. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) TYPICAL DETAILS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  5. 14. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    14. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) SECTIONS AND DETAILS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  6. 21. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    21. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) ERECTION PLAN-PIER NO. 4 - Brooklyn Army Supply Base, Pier 4, Brooklyn, Kings County, NY

  7. 16. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    16. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) DETAILS OF INSHORE ENDS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  8. 13. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    13. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) ARMY SUPPLY BASE-PLAN OF CONSTRUCTION PLANT - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  9. 17. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    17. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) DETAILS OF OUTSHORE ENDS-PIERS 2, 3, AND 4 - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  10. 19. Photocopy of original drawing by Cass Gilbert, 1918 (original ...

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

    19. Photocopy of original drawing by Cass Gilbert, 1918 (original in possession of NYC Economic Development Corp.) BRIDGES BETWEEN WAREHOUSE A AND PIERS - Brooklyn Army Supply Base, Pier 2, Brooklyn, Kings County, NY

  11. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Building 253; 1920. - Mare Island Naval Shipyard, Supply Building, Walnut Avenue, southeast corner of Walnut Avenue & Fifth Street, Vallejo, Solano County, CA

  12. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Coal sheds with coals; 1906. - Mare Island Naval Shipyard, Coal Sheds, Waterfront Avenue, northwest corner of Waterfront Avenue & Fourth Street, Vallejo, Solano County, CA

  13. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. QUARTERS A IN THE SNOW; 1913. - Mare Island Naval Shipyard, Commandant's Quarters, Walnut Avenue, west side near Eighth Street, Vallejo, Solano County, CA

  14. First molecules, biological chirality, origin(s) of life.

    PubMed

    Caglioti, Luciano; Micskei, Károly; Pályi, Gyula

    2011-01-01

    Origin(s) of biological chirality appear(s) to be intimately connected to origin(s) of life. Prebiotic evolution toward these important turning points can be traced back to single chiral molecules. These can be small (monomeric) units as amino acids or monosaccharides or oligomers as oligo-RNA type molecules. Earlier speculations about these two kinds of entries to biological chirality are critically reviewed.

  15. Conscientiousness: Origins in Childhood?

    PubMed Central

    Eisenberg, Nancy; Duckworth, Angela L.; Spinrad, Tracy L.; Valiente, Carlos

    2012-01-01

    In this review, we evaluate developmental and personality research with the aim of determining if the personality trait of conscientiousness can be identified in children and adolescents. After concluding that conscientiousness does emerge in childhood, we discuss the developmental origins of conscientiousness with a specific focus on self-regulation, academic motivation, and internalized compliance/internalization of standards. Based on the accumulated body of evidence, we conclude that self-regulation fosters conscientiousness later in life, both directly and via academic motivation and internalized compliance with norms. We argue that elements of conscientiousness are evident by early childhood, self-regulation skills are likely a core developmental component of conscientiousness, and despite the contribution of heredity to the aforementioned aspects of functioning, environmental factors likely contribute to conscientiousness. PMID:23244405

  16. Mechanical origin of aftershocks

    PubMed Central

    Lippiello, E.; Giacco, F.; Marzocchi, W.; Godano, C.; de Arcangelis, L.

    2015-01-01

    Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that positive correlations among parameters controlling aftershock occurrence in time, energy and space are a stable feature of seismicity independently of magnitude range and geographic areas. We explain the ensemble of experimental findings by means of a description of the Earth Crust as an heterogeneous elastic medium coupled with a Maxwell viscoelastic asthenosphere. Our results show that heterogeneous stress distribution in an elastic layer combined with a coupling to a viscous flow are sufficient ingredients to describe the physics of aftershock triggering. PMID:26497720

  17. Origins of Stellar Halos

    NASA Astrophysics Data System (ADS)

    Johnston, Kathryn V.

    2016-08-01

    This contribution reviews ideas about the origins of stellar halos. It includes discussion of the theoretical understanding of and observational evidence for stellar populations formed ``in situ'' (meaning formed in orbits close to their current ones), ``kicked-out'' (meaning formed in the inner galaxy in orbits unlike their current ones) and ``accreted'' (meaning formed in a dark matter halo other than the one they currently occupy). At this point there is general agreement that a significant fraction of any stellar halo population is likely ``accreted''. There is modest evidence for the presence of a ``kicked-out'' population around both the Milky Way and M31. Our theoretical understanding of and the observational evidence for an ``in situ'' population are less clear.

  18. Origins of hydration lubrication.

    PubMed

    Ma, Liran; Gaisinskaya-Kipnis, Anastasia; Kampf, Nir; Klein, Jacob

    2015-01-14

    Why is friction in healthy hips and knees so low? Hydration lubrication, according to which hydration shells surrounding charges act as lubricating elements in boundary layers (including those coating cartilage in joints), has been invoked to account for the extremely low sliding friction between surfaces in aqueous media, but not well understood. Here we report the direct determination of energy dissipation within such sheared hydration shells. By trapping hydrated ions in a 0.4-1 nm gap between atomically smooth charged surfaces as they slide past each other, we are able to separate the dissipation modes of the friction and, in particular, identify the viscous losses in the subnanometre hydration shells. Our results shed light on the origins of hydration lubrication, with potential implications both for aqueous boundary lubricants and for biolubrication.

  19. The origins of informatics.

    PubMed Central

    Collen, M F

    1994-01-01

    This article summarizes the origins of informatics, which is based on the science, engineering, and technology of computer hardware, software, and communications. In just four decades, from the 1950s to the 1990s, computer technology has progressed from slow, first-generation vacuum tubes, through the invention of the transistor and its incorporation into microprocessor chips, and ultimately, to fast, fourth-generation very-large-scale-integrated silicon chips. Programming has undergone a parallel transformation, from cumbersome, first-generation, machine languages to efficient, fourth-generation application-oriented languages. Communication has evolved from simple copper wires to complex fiberoptic cables in computer-linked networks. The digital computer has profound implications for the development and practice of clinical medicine. PMID:7719803

  20. Conscientiousness: origins in childhood?

    PubMed

    Eisenberg, Nancy; Duckworth, Angela L; Spinrad, Tracy L; Valiente, Carlos

    2014-05-01

    In this review, we evaluate developmental and personality research with the aim of determining whether the personality trait of conscientiousness can be identified in children and adolescents. After concluding that conscientiousness does emerge in childhood, we discuss the developmental origins of conscientiousness with a specific focus on self-regulation, academic motivation, and internalized compliance/internalization of standards. On the basis of the accumulated body of evidence, we conclude that self-regulation fosters conscientiousness later in life, both directly and via academic motivation and internalized compliance with norms. We argue that elements of conscientiousness are evident by early childhood; self-regulation skills are likely a core developmental component of conscientiousness; and despite the contribution of heredity to the aforementioned aspects of functioning, environmental factors likely contribute to conscientiousness.

  1. Mechanical origin of aftershocks.

    PubMed

    Lippiello, E; Giacco, F; Marzocchi, W; Godano, C; de Arcangelis, L

    2015-10-26

    Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that positive correlations among parameters controlling aftershock occurrence in time, energy and space are a stable feature of seismicity independently of magnitude range and geographic areas. We explain the ensemble of experimental findings by means of a description of the Earth Crust as an heterogeneous elastic medium coupled with a Maxwell viscoelastic asthenosphere. Our results show that heterogeneous stress distribution in an elastic layer combined with a coupling to a viscous flow are sufficient ingredients to describe the physics of aftershock triggering.

  2. The Origin of Mercury

    NASA Astrophysics Data System (ADS)

    Benz, W.; Anic, A.; Horner, J.; Whitby, J. A.

    Mercury's unusually high mean density has always been attributed to special circumstances that occurred during the formation of the planet or shortly thereafter, and due to the planet's close proximity to the Sun. The nature of these special circumstances is still being debated and several scenarios, all proposed more than 20 years ago, have been suggested. In all scenarios, the high mean density is the result of severe fractionation occurring between silicates and iron. It is the origin of this fractionation that is at the centre of the debate: is it due to differences in condensation temperature and/or in material characteristics (e.g. density, strength)? Is it because of mantle evaporation due to the close proximity to the Sun? Or is it due to the blasting off of the mantle during a giant impact?

  3. Origin of Prometheus Eccentricity

    NASA Astrophysics Data System (ADS)

    Rappaport, N. J.; Longaretti, P.

    2006-12-01

    A number of Saturn's small satellites, from Atlas to the coorbital satellites Janus and Epimetheus, move on orbits just outside the main rings of the planet. These satellites undergo extremely rapid resonant interaction with the rings and outward motion, strongly suggesting that they originated in Saturn's A ring. However, their eccentricities, of the order of 1/1000 are several orders of magnitude larger than what could be expected if the small satellites formed in the ring. This paper represents a first step to providing an explanation for this phenomenon, by focusing on the dynamical processes that have affected the eccentricity of Prometheus. The explanation invokes past resonances with the coorbital satellites combined with chaos due to overlapping of these resonances.

  4. The origin of humor.

    PubMed

    Howe, N E

    2002-09-01

    Humor is spread throughout every culture on earth and occupies a large portion of our literature and social interaction. It is so deeply rooted in our culture that it may be a defining characteristic of our species. Yet there has been comparatively little effort to understand its origin. According to the Accepted Theory of Humor all jokes begin with a buildup of tension while an initial paradigm is formed. When the punch line occurs the subject must realign his thinking to accommodate the differences between the initial paradigm and the sudden burst of new information. The Mind Reading Hypothesis extends the accepted theory of humor to include a relationship between the observer and the subject of the humor. The actual source of amusement is the observation of the resolution in the mind of the subject of the collision between old perception and new reality.

  5. Origins of adaptive immunity.

    PubMed

    Liongue, Clifford; John, Liza B; Ward, Alister

    2011-01-01

    Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity.

  6. Actinides and Life's Origins

    NASA Astrophysics Data System (ADS)

    Adam, Zachary

    2007-12-01

    There are growing indications that life began in a radioactive beach environment. A geologic framework for the origin or support of life in a Hadean heavy mineral placer beach has been developed, based on the unique chemical properties of the lower-electronic actinides, which act as nuclear fissile and fertile fuels, radiolytic energy sources, oligomer catalysts, and coordinating ions (along with mineralogically associated lanthanides) for prototypical prebiotic homonuclear and dinuclear metalloenzymes. A four-factor nuclear reactor model was constructed to estimate how much uranium would have been required to initiate a sustainable fission reaction within a placer beach sand 4.3 billion years ago. It was calculated that about 1-8 weight percent of the sand would have to have been uraninite, depending on the weight percent, uranium enrichment, and quantity of neutron poisons present within the remaining placer minerals. Radiolysis experiments were conducted with various solvents with the use of uranium- and thorium-rich minerals (metatorbernite and monazite, respectively) as proxies for radioactive beach sand in contact with different carbon, hydrogen, oxygen, and nitrogen reactants. Radiation bombardment ranged in duration of exposure from 3 weeks to 6 months. Low levels of acetonitrile (estimated to be on the order of parts per billion in concentration) were conclusively identified in 2 setups and tentatively indicated in a 3rd by gas chromatography/mass spectrometry. These low levels have been interpreted within the context of a Hadean placer beach prebiotic framework to demonstrate the promise of investigating natural nuclear reactors as power production sites that might have assisted the origins of life on young rocky planets with a sufficiently differentiated crust/mantle structure. Future investigations are recommended to better quantify the complex relationships between energy release, radioactive grain size, fissionability, reactant phase, phosphorus

  7. Actinides and Life's Origins.

    PubMed

    Adam, Zachary

    2007-12-01

    There are growing indications that life began in a radioactive beach environment. A geologic framework for the origin or support of life in a Hadean heavy mineral placer beach has been developed, based on the unique chemical properties of the lower-electronic actinides, which act as nuclear fissile and fertile fuels, radiolytic energy sources, oligomer catalysts, and coordinating ions (along with mineralogically associated lanthanides) for prototypical prebiotic homonuclear and dinuclear metalloenzymes. A four-factor nuclear reactor model was constructed to estimate how much uranium would have been required to initiate a sustainable fission reaction within a placer beach sand 4.3 billion years ago. It was calculated that about 1-8 weight percent of the sand would have to have been uraninite, depending on the weight percent, uranium enrichment, and quantity of neutron poisons present within the remaining placer minerals. Radiolysis experiments were conducted with various solvents with the use of uraniumand thorium-rich minerals (metatorbernite and monazite, respectively) as proxies for radioactive beach sand in contact with different carbon, hydrogen, oxygen, and nitrogen reactants. Radiation bombardment ranged in duration of exposure from 3 weeks to 6 months. Low levels of acetonitrile (estimated to be on the order of parts per billion in concentration) were conclusively identified in 2 setups and tentatively indicated in a 3(rd) by gas chromatography/mass spectrometry. These low levels have been interpreted within the context of a Hadean placer beach prebiotic framework to demonstrate the promise of investigating natural nuclear reactors as power production sites that might have assisted the origins of life on young rocky planets with a sufficiently differentiated crust/mantle structure. Future investigations are recommended to better quantify the complex relationships between energy release, radioactive grain size, fissionability, reactant phase, phosphorus

  8. The Origin of Alcohol Proof

    ERIC Educational Resources Information Center

    Jensen, William B.

    2004-01-01

    The origin of the "proof" system for measuring the ethanol content of alcoholic beverages is presented. The proof system was originally established for purposes of taxing liquors according to their alcohol content and is different in different countries.

  9. Origins of GEMS Grains

    NASA Technical Reports Server (NTRS)

    Messenger, S.; Walker, R. M.

    2012-01-01

    Interplanetary dust particles (IDPs) collected in the Earth s stratosphere contain high abundances of submicrometer amorphous silicates known as GEMS grains. From their birth as condensates in the outflows of oxygen-rich evolved stars, processing in interstellar space, and incorporation into disks around new stars, amorphous silicates predominate in most astrophysical environments. Amorphous silicates were a major building block of our Solar System and are prominent in infrared spectra of comets. Anhydrous interplanetary dust particles (IDPs) thought to derive from comets contain abundant amorphous silicates known as GEMS (glass with embedded metal and sulfides) grains. GEMS grains have been proposed to be isotopically and chemically homogenized interstellar amorphous silicate dust. We evaluated this hypothesis through coordinated chemical and isotopic analyses of GEMS grains in a suite of IDPs to constrain their origins. GEMS grains show order of magnitude variations in Mg, Fe, Ca, and S abundances. GEMS grains do not match the average element abundances inferred for ISM dust containing on average, too little Mg, Fe, and Ca, and too much S. GEMS grains have complementary compositions to the crystalline components in IDPs suggesting that they formed from the same reservoir. We did not observe any unequivocal microstructural or chemical evidence that GEMS grains experienced prolonged exposure to radiation. We identified four GEMS grains having O isotopic compositions that point to origins in red giant branch or asymptotic giant branch stars and supernovae. Based on their O isotopic compositions, we estimate that 1-6% of GEMS grains are surviving circumstellar grains. The remaining 94-99% of GEMS grains have O isotopic compositions that are indistinguishable from terrestrial materials and carbonaceous chondrites. These isotopically solar GEMS grains either formed in the Solar System or were completely homogenized in the interstellar medium (ISM). However, the

  10. Origins of mass

    NASA Astrophysics Data System (ADS)

    Wilczek, Frank

    2012-10-01

    Newtonian mechanics posited mass as a primary quality of matter, incapable of further elucidation. We now see Newtonian mass as an emergent property. That mass-concept is tremendously useful in the approximate description of baryon-dominated matter at low energy — that is, the standard "matter" of everyday life, and of most of science and engineering — but it originates in a highly contingent and non-trivial way from more basic concepts. Most of the mass of standard matter, by far, arises dynamically, from back-reaction of the color gluon fields of quantum chromodynamics (QCD). Additional quantitatively small, though physically crucial, contributions come from the intrinsic masses of elementary quanta (electrons and quarks). The equations for massless particles support extra symmetries — specifically scale, chiral, and gauge symmetries. The consistency of the standard model relies on a high degree of underlying gauge and chiral symmetry, so the observed non-zero masses of many elementary particles (W and Z bosons, quarks, and leptons) requires spontaneous symmetry breaking. Superconductivity is a prototype for spontaneous symmetry breaking and for mass-generation, since photons acquire mass inside superconductors. A conceptually similar but more intricate form of all-pervasive (i.e. cosmic) superconductivity, in the context of the electroweak standard model, gives us a successful, economical account of W and Z boson masses. It also allows a phenomenologically successful, though profligate, accommodation of quark and lepton masses. The new cosmic superconductivity, when implemented in a straightforward, minimal way, suggests the existence of a remarkable new particle, the so-called Higgs particle. The mass of the Higgs particle itself is not explained in the theory, but appears as a free parameter. Earlier results suggested, and recent observations at the Large Hadron Collider (LHC) may indicate, the actual existence of the Higgs particle, with mass m H

  11. Origins of mass

    NASA Astrophysics Data System (ADS)

    Wilczek, Frank

    2012-10-01

    Newtonian mechanics posited mass as a primary quality of matter, incapable of further elucidation. We now see Newtonian mass as an emergent property. That mass-concept is tremendously useful in the approximate description of baryon-dominated matter at low energy — that is, the standard "matter" of everyday life, and of most of science and engineering — but it originates in a highly contingent and non-trivial way from more basic concepts. Most of the mass of standard matter, by far, arises dynamically, from back-reaction of the color gluon fields of quantum chromodynamics (QCD). Additional quantitatively small, though physically crucial, contributions come from the intrinsic masses of elementary quanta (electrons and quarks). The equations for massless particles support extra symmetries — specifically scale, chiral, and gauge symmetries. The consistency of the standard model relies on a high degree of underlying gauge and chiral symmetry, so the observed non-zero masses of many elementary particles ( W and Z bosons, quarks, and leptons) requires spontaneous symmetry breaking. Superconductivity is a prototype for spontaneous symmetry breaking and for mass-generation, since photons acquire mass inside superconductors. A conceptually similar but more intricate form of all-pervasive ( i.e. cosmic) superconductivity, in the context of the electroweak standard model, gives us a successful, economical account of W and Z boson masses. It also allows a phenomenologically successful, though profligate, accommodation of quark and lepton masses. The new cosmic superconductivity, when implemented in a straightforward, minimal way, suggests the existence of a remarkable new particle, the so-called Higgs particle. The mass of the Higgs particle itself is not explained in the theory, but appears as a free parameter. Earlier results suggested, and recent observations at the Large Hadron Collider (LHC) may indicate, the actual existence of the Higgs particle, with mass m H

  12. Origins of magnetospheric physics

    SciTech Connect

    Van Allen, J.A.

    1983-01-01

    The history of the scientific investigation of the earth magnetosphere during the period 1946-1960 is reviewed, with a focus on satellite missions leading to the discovery of the inner and outer radiation belts. Chapters are devoted to ground-based studies of the earth magnetic field through the 1930s, the first U.S. rocket flights carrying scientific instruments, the rockoon flights from the polar regions (1952-1957), U.S. planning for scientific use of artificial satellites (1956), the launch of Sputnik I (1957), the discovery of the inner belt by Explorers I and III (1958), the Argus high-altitude atomic-explosion tests (1958), the confirmation of the inner belt and discovery of the outer belt by Explorer IV and Pioneers I-V, related studies by Sputniks II and III and Luniks I-III, and the observational and theoretical advances of 1959-1961. Photographs, drawings, diagrams, graphs, and copies of original notes and research proposals are provided. 227 references.

  13. Origin of Neutron Stars

    NASA Astrophysics Data System (ADS)

    Brecher, K.

    1999-12-01

    The origin of the concept of neutron stars can be traced to two brief, incredibly insightful publications. Work on the earlier paper by Lev Landau (Phys. Z. Sowjetunion, 1, 285, 1932) actually predated the discovery of neutrons. Nonetheless, Landau arrived at the notion of a collapsed star with the density of a nucleus (really a "nucleus star") and demonstrated (at about the same time as, and independent of, Chandrasekhar) that there is an upper mass limit for dense stellar objects of about 1.5 solar masses. Perhaps even more remarkable is the abstract of a talk presented at the December 1933 meeting of the American Physical Society published by Walter Baade and Fritz Zwicky in 1934 (Phys. Rev. 45, 138). It followed the discovery of the neutron by just over a year. Their report, which was about the same length as the present abstract: (1) invented the concept and word supernova; (2) suggested that cosmic rays are produced by supernovae; and (3) in the authors own words, proposed "with all reserve ... the view that supernovae represent the transitions from ordinary stars to neutron stars (italics), which in their final stages consist of extremely closely packed neutrons." The abstract by Baade and Zwicky probably contains the highest density of new, important (and correct) ideas in high energy astrophysics ever published in a single paper. In this talk, we will discuss some of the facts and myths surrounding these two publications.

  14. DHCP Origin Traceback

    NASA Astrophysics Data System (ADS)

    Majumdar, Saugat; Kulkarni, Dhananjay; Ravishankar, Chinya V.

    Imagine that the DHCP server is under attack from malicious hosts in your network. How would you know where these DHCP packets are coming from, or which path they took in the network? This paper investigates the problem of determining the origin of a DHCP packet in a network. We propose a practical method for adding a new option field that does not violate any RFC's, which we believe should be a crucial requirement while proposing any related solution. The new DHCP option will contain the ingress port and the switch MAC address. We recommend that this new option be added at the edge so that we can use the recorded value for performing traceback. The computational overhead of our solution is low, and the related network management tasks are low as well. We also address issues related to securing the field in order to maintain privacy of switch MAC addresses, fragmentation of packets, and possible attack scenarios. Our study shows that the traceback scheme is effective and practical to use in most network environments.

  15. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2016-04-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  16. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2014-05-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  17. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2015-04-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. . As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  18. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2013-04-01

    When the Earth was formed, it was in a state of burning heat. As time went by, temperature on the planet's surface was falling due to radiation and heat transfer, and various components (crusts) began taking solid form at the Earth's poles. The formation of crusts took place at the Earth's poles, because the stirring of burning and fluid masses on the surface of the Earth was significantly slighter there than it was on the equator. Due to centrifugal force and Coriolis Effect, these solid masses headed towards the equator; those originating from the North Pole followed a south-western course, while those originating from the South Pole followed a north-western course and there they rotated from west to east at a lower speed than the underlying burning and liquid earth, because of their lower initial linear velocity, their solid state and inertia. Because inertia is proportional to mass, the initially larger solid body swept all new solid ones, incorporating them to its western side. The density of the new solid masses was higher, because the components on the surface would freeze and solidify first, before the underlying thicker components. As a result, the western side of the initial islet of solid rocks submerged, while the east side elevated. As a result of the above, this initial islet began to spin in reverse, and after taking on the shape of a sphere, it formed the "heart" of the Moon. The Moon-sphere, rolling on the equator, would sink the solid rocks that continued to descend from the Earth's poles. The sinking rocks partially melted because of higher temperatures in the greater depths that the Moon descended to, while part of the rocks' mass bonded with the Moon and also served as a heat-insulating material, preventing the descended side of the sphere from melting. Combined with the Earth's liquid mass that covered its emerging eastern surface, new sphere-shaped shells were created, with increased density and very powerful structural cohesion. During the

  19. THE COSMIC ORIGINS SPECTROGRAPH

    SciTech Connect

    Green, James C.; Michael Shull, J.; Snow, Theodore P.; Stocke, John; Froning, Cynthia S.; Osterman, Steve; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Sembach, Kenneth; Linsky, Jeffrey L.; Savage, Blair D.; Siegmund, Oswald H. W.; Spencer, John; Alan Stern, S.; Welsh, Barry; and others

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F{sub {lambda}} Almost-Equal-To 1.0 Multiplication-Sign 10{sup -14} erg cm{sup -2} s{sup -1} A{sup -1}, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Ly{alpha} absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  20. The Cosmic Origins Spectrograph

    NASA Technical Reports Server (NTRS)

    Green, James C.; Froning, Cynthia S.; Osterman, Steve; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Linsky, Jeffrey L.; Savage, Blair D.; Sembach, Kenneth; Shull, J. Michael; Siegmund, Oswald H. W.; Snow, Theodore P.; Spencer, John; Stern, S. Alan; Stocke, John; Welsh, Barry; Beland, Stephane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Keeney, Brian; McPhate, Jason; Penton, Steven V; Andrews, John; Morse, Jon

    2010-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in May 2009, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F(sub lambda) approximates 1.0 X 10(exp -14) ergs/s/cm2/Angstrom, COS can achieve comparable signal to noise (when compared to STIS echelle modes) in 1-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (September 2009 - June 2011) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is 9 times that sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of June 2011. COS has measured, for the first time with high reliability, broad Lya absorbers and Ne VIII in the intergalactic medium, and observed the HeII reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  1. The Cosmic Origins Spectrograph

    NASA Astrophysics Data System (ADS)

    Green, James C.; Froning, Cynthia S.; Osterman, Steve; Ebbets, Dennis; Heap, Sara H.; Leitherer, Claus; Linsky, Jeffrey L.; Savage, Blair D.; Sembach, Kenneth; Shull, J. Michael; Siegmund, Oswald H. W.; Snow, Theodore P.; Spencer, John; Stern, S. Alan; Stocke, John; Welsh, Barry; Béland, Stéphane; Burgh, Eric B.; Danforth, Charles; France, Kevin; Keeney, Brian; McPhate, Jason; Penton, Steven V.; Andrews, John; Brownsberger, Kenneth; Morse, Jon; Wilkinson, Erik

    2012-01-01

    The Cosmic Origins Spectrograph (COS) is a moderate-resolution spectrograph with unprecedented sensitivity that was installed into the Hubble Space Telescope (HST) in 2009 May, during HST Servicing Mission 4 (STS-125). We present the design philosophy and summarize the key characteristics of the instrument that will be of interest to potential observers. For faint targets, with flux F λ ≈ 1.0 × 10-14 erg cm-2 s-1 Å-1, COS can achieve comparable signal to noise (when compared to Space Telescope Imaging Spectrograph echelle modes) in 1%-2% of the observing time. This has led to a significant increase in the total data volume and data quality available to the community. For example, in the first 20 months of science operation (2009 September-2011 June) the cumulative redshift pathlength of extragalactic sight lines sampled by COS is nine times than sampled at moderate resolution in 19 previous years of Hubble observations. COS programs have observed 214 distinct lines of sight suitable for study of the intergalactic medium as of 2011 June. COS has measured, for the first time with high reliability, broad Lyα absorbers and Ne VIII in the intergalactic medium, and observed the He II reionization epoch along multiple sightlines. COS has detected the first CO emission and absorption in the UV spectra of low-mass circumstellar disks at the epoch of giant planet formation, and detected multiple ionization states of metals in extra-solar planetary atmospheres. In the coming years, COS will continue its census of intergalactic gas, probe galactic and cosmic structure, and explore physics in our solar system and Galaxy.

  2. "Origin," "creation," and "origin of life" some conceptual considerations.

    PubMed

    Charpa, Ulrich

    2012-01-01

    This paper opens by drawing attention to the fact that there is some conceptual confusion with regard to "origin" and "creation." This has its historical roots in the beginnings of modern science and undoubtedly affects our positioning towards the evolutionism/creationism-debate. This article argues that there are relevant ontological, epistemological, thematic, methodological, and logical differences between "origin" and "creation." As a result, the analysis suggests keeping the usage of both concepts strictly quite separate. Creation is not simply another word for origin nor does it stand for an (from a rigid scientific point of view) awkward example of an origin. Irrespective of the apparent similarities as explanatory factors, origin and creation belong to fundamentally different types of concepts. Consequently, "origin of life" and those scientific projects connected to it present themselves as something distinct that neither competes nor meshes with thinking about creation.

  3. The Origin of Mercury

    NASA Astrophysics Data System (ADS)

    Benz, W.; Anic, A.; Horner, J.; Whitby, J. A.

    2007-10-01

    Mercury’s unusually high mean density has always been attributed to special circumstances that occurred during the formation of the planet or shortly thereafter, and due to the planet’s close proximity to the Sun. The nature of these special circumstances is still being debated and several scenarios, all proposed more than 20 years ago, have been suggested. In all scenarios, the high mean density is the result of severe fractionation occurring between silicates and iron. It is the origin of this fractionation that is at the centre of the debate: is it due to differences in condensation temperature and/or in material characteristics (e.g. density, strength)? Is it because of mantle evaporation due to the close proximity to the Sun? Or is it due to the blasting off of the mantle during a giant impact? In this paper we investigate, in some detail, the fractionation induced by a giant impact on a proto-Mercury having roughly chondritic elemental abundances. We have extended the previous work on this hypothesis in two significant directions. First, we have considerably increased the resolution of the simulation of the collision itself. Second, we have addressed the fate of the ejecta following the impact by computing the expected reaccretion timescale and comparing it to the removal timescale from gravitational interactions with other planets (essentially Venus) and the Poynting Robertson effect. To compute the latter, we have determined the expected size distribution of the condensates formed during the cooling of the expanding vapor cloud generated by the impact. We find that, even though some ejected material will be reaccreted, the removal of the mantle of proto-Mercury following a giant impact can indeed lead to the required long-term fractionation between silicates and iron and therefore account for the anomalously high mean density of the planet. Detailed coupled dynamical chemical modeling of this formation mechanism should be carried out in such a way as to

  4. Photocopy of original drawings (original located at the National Archives, ...

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

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-14). Dept. of yards and docks, "Chapel amplifier support," October 1945. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  5. Photocopy of original drawings (original located at the National Archives, ...

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

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-25) William Jeffries Associates, A.I.A., "Repair to stained glass window, building 104, elevation & details," September 1952. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  6. 121. Photocopy of original construction drawing, 29 May 1935. (Original ...

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

    121. Photocopy of original construction drawing, 29 May 1935. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) (M-5-12, Sheet No. 5) SPILLWAY DAM SECTION 17 FEET DOWNSTREAM FROM AXIS OF DAM - FROM PIER 13 TO ABUTMENT 2. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  7. 123. Photocopy of original construction drawing, 22 May 1935. (Original ...

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

    123. Photocopy of original construction drawing, 22 May 1935. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) (M-5-12, Sheet No. 6) SPILLWAY DAM SECTION 17 FEET DOWNSTREAM FROM AXIS OF DAM - FROM PIERS NO. 5 TO 12. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  8. Photocopy of original drawings (original located at the National Archives, ...

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

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # 104-A-22), showing current floor plan. Department of the Navy, Bureau of Yards and Docks, "Record drawing, N.D. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  9. 8. Photocopy of original USRS glass plate slide (from original ...

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

    8. Photocopy of original USRS glass plate slide (from original slide on file at National Archives, Rocky Mountain Region, Denver, Colorado) Photographer unknown, ca. 1908 The diversion weir of the Okanogan National Irrigation Project - Salmon Creek Diversion Dam, Salmon Creek, Okanogan, Okanogan County, WA

  10. 117. Photocopy of original construction drawing, 29 May 1935. (Original ...

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

    117. Photocopy of original construction drawing, 29 May 1935. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) (M-5-12, Sheet No. 13) SPILLWAY DAN PIERS 2 TO 9 INCL. AND NORTH SIDE PIER 10 REINFORCING STEEL. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  11. 114. Photocopy of original construction drawing, 14 August 1935. (Original ...

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

    114. Photocopy of original construction drawing, 14 August 1935. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) (M-5-8, Sheet No. 14) SPILLWAY DAM FISHWAY ENTRANCE BAY DIFFUSION CHAMBER BEAN DETAILS. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  12. Photocopy of original drawings (original located at the National Archives, ...

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

    Photocopy of original drawings (original located at the National Archives, San Bruno, California, Navy # A-21). Dept. of the Navy District Public Works Office, "additions, floor plan, elevations & details; architectural, mechanical & electrical," May 1963. - Mare Island Naval Shipyard, St. Peter's Chapel, Walnut Street & Cedar Parkway, Vallejo, Solano County, CA

  13. Photograph of original drawing (original in possession of National Passenger ...

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

    Photograph of original drawing (original in possession of National Passenger Railroad Corporation). Plans, Elevations, and Details of Stair Canopies (n.d.) - North Philadelphia Station, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

  14. 16. Photocopy of original USRS photograph (from original print in ...

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

    16. Photocopy of original USRS photograph (from original print in the Umatilla Project History 1918, on file at National Archives, Rocky Mountain Region, Denver, Colorado) Photographer unknown, ca. 1918. Office of U.S. Reclamation Service - Hermiston, Umatilla Project, Oregon - Former Umatilla Project Headquarters Buildings, Office, Hermiston, Umatilla County, OR

  15. 56. Photograph of Original Plan (original plans in the possession ...

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

    56. Photograph of Original Plan (original plans in the possession of the Los Angeles Union Passenger Terminal Corporation) BAGGAGE AND EXPRESS UNIT, MAIN FLOOR AND BOILER ROOM PLANS, SECTIONS IV-V - Los Angeles Union Passenger Terminal, Tracks & Shed, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  16. 55. Photograph of Original Plan (original plans in the possession ...

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

    55. Photograph of Original Plan (original plans in the possession of the Los Angeles Union Passenger Terminal Corporation) BAGGAGE AND EXPRESS UNITY, STREET LEVEL FLOOR PLAN, SECTION III - Los Angeles Union Passenger Terminal, Tracks & Shed, 800 North Alameda Street, Los Angeles, Los Angeles County, CA

  17. 113. Photocopy of original construction drawing, 16 September 1935. (Original ...

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

    113. Photocopy of original construction drawing, 16 September 1935. (Original print in the possession of U.S. Army Corps of Engineers, Portland District, Portland, OR.) (M-5-8, Sheet No. 23) SPILLWAY DAN BRADFORD ISLAND FISH LADDER SECTION 27 GENERAL PLAN AND SHORE ELEVATION. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  18. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Dry dock 2 with three submarines and one sailing ship; 1914. - Mare Island Naval Shipyard, Drydock No. 2, California Avenue, east side near Ninth Street, Vallejo, Solano County, CA

  19. Photocopy of photograph (original located at Mare Island Archives). Original ...

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

    Photocopy of photograph (original located at Mare Island Archives). Original photographer unknown. Lithograph of Mare Island, "showing the works already completed in the Navy Yard and the US. Frigate "Independence"; 1855. - Mare Island Naval Shipyard, East of Nave Drive, Vallejo, Solano County, CA

  20. The Origins of Soviet Sociolinguistics.

    ERIC Educational Resources Information Center

    Brandist, Craig

    2003-01-01

    Discusses the origins of Soviet sociolinguistics and suggests that the historical significance of the reception and reinterpretation of these ideas is considerable, leading to a reconsideration of the origins of sociolinguistics and the relationship between Marxism and the language sciences in the early years of the Soviet Union. (Author/VWL)

  1. The Origin of Malignant Malaria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plasmodium falciparum is the causative agent of malignant malaria, which is among the most severe human infectious diseases. Despite its overwhelming significance to human health, the parasite’s origins remain unclear. The favored origin hypothesis holds that P. falciparum and its closest known rel...

  2. 17. Photocopy of original USRS photograph (from original print in ...

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

    17. Photocopy of original USRS photograph (from original print in the Umatilla Project History 1920, on file at National Archives, Rocky Mountain Region, Denver, Colorado) Photographer unknown, ca. 1920. Project office and employees - reading from left to right: Una H. Keck, Geo. C. Patterson, H.M. Schilling, Maurice D. Scroggs, Carl M. Voyen, Chas. Taylor, C.D. Porter - Former Umatilla Project Headquarters Buildings, Office, Hermiston, Umatilla County, OR

  3. The origins of originality: the neural bases of creative thinking and originality.

    PubMed

    Shamay-Tsoory, S G; Adler, N; Aharon-Peretz, J; Perry, D; Mayseless, N

    2011-01-01

    Although creativity has been related to prefrontal activity, recent neurological case studies postulate that patients who have left frontal and temporal degeneration involving deterioration of language abilities may actually develop de novo artistic abilities. In this study, we propose a neural and cognitive model according to which a balance between the two hemispheres affects a major aspect of creative cognition, namely, originality. In order to examine the neural basis of originality, that is, the ability to produce statistically infrequent ideas, patients with localized lesions in the medial prefrontal cortex (mPFC), inferior frontal gyrus (IFG), and posterior parietal and temporal cortex (PC), were assessed by two tasks involving divergent thinking and originality. Results indicate that lesions in the mPFC involved the most profound impairment in originality. Furthermore, precise anatomical mapping of lesions indicated that while the extent of lesion in the right mPFC was associated with impaired originality, lesions in the left PC were associated with somewhat elevated levels of originality. A positive correlation between creativity scores and left PC lesions indicated that the larger the lesion is in this area the greater the originality. On the other hand, a negative correlation was observed between originality scores and lesions in the right mPFC. It is concluded that the right mPFC is part of a right fronto-parietal network which is responsible for producing original ideas. It is possible that more linear cognitive processing such as language, mediated by left hemisphere structures interferes with creative cognition. Therefore, lesions in the left hemisphere may be associated with elevated levels of originality.

  4. Origin of the Uranian satellites

    NASA Technical Reports Server (NTRS)

    Pollack, James B.; Lunine, Jonathan I.; Tittemore, William C.

    1991-01-01

    The current understanding of the origin of the Uranian satellites is assessed by reviewing relevant data on the Uranian satellites, including those obtained by Voyager, and comparing these properties with those of the satellites of the other outer planets. The nature of the early solar system, including the origin of the giant planets, is discussed as a preface to alternative hypotheses for the origin of the nebular disk within which the Uranian satellites formed. The chemical and physical properties of this disk are discussed, as well as the accretion of the satellites from disk solid matter. Predictions of alternative scenarios for the satellites' origin with the relevant observational constraint are compared. The orbital evolution of the larger satellites of Uranus is discussed to gain an understanding of their present orbital properties and possibly important past tidal heating episodes.

  5. Endosymbiotic theories for eukaryote origin

    PubMed Central

    Martin, William F.; Garg, Sriram; Zimorski, Verena

    2015-01-01

    For over 100 years, endosymbiotic theories have figured in thoughts about the differences between prokaryotic and eukaryotic cells. More than 20 different versions of endosymbiotic theory have been presented in the literature to explain the origin of eukaryotes and their mitochondria. Very few of those models account for eukaryotic anaerobes. The role of energy and the energetic constraints that prokaryotic cell organization placed on evolutionary innovation in cell history has recently come to bear on endosymbiotic theory. Only cells that possessed mitochondria had the bioenergetic means to attain eukaryotic cell complexity, which is why there are no true intermediates in the prokaryote-to-eukaryote transition. Current versions of endosymbiotic theory have it that the host was an archaeon (an archaebacterium), not a eukaryote. Hence the evolutionary history and biology of archaea increasingly comes to bear on eukaryotic origins, more than ever before. Here, we have compiled a survey of endosymbiotic theories for the origin of eukaryotes and mitochondria, and for the origin of the eukaryotic nucleus, summarizing the essentials of each and contrasting some of their predictions to the observations. A new aspect of endosymbiosis in eukaryote evolution comes into focus from these considerations: the host for the origin of plastids was a facultative anaerobe. PMID:26323761

  6. Endosymbiotic theories for eukaryote origin.

    PubMed

    Martin, William F; Garg, Sriram; Zimorski, Verena

    2015-09-26

    For over 100 years, endosymbiotic theories have figured in thoughts about the differences between prokaryotic and eukaryotic cells. More than 20 different versions of endosymbiotic theory have been presented in the literature to explain the origin of eukaryotes and their mitochondria. Very few of those models account for eukaryotic anaerobes. The role of energy and the energetic constraints that prokaryotic cell organization placed on evolutionary innovation in cell history has recently come to bear on endosymbiotic theory. Only cells that possessed mitochondria had the bioenergetic means to attain eukaryotic cell complexity, which is why there are no true intermediates in the prokaryote-to-eukaryote transition. Current versions of endosymbiotic theory have it that the host was an archaeon (an archaebacterium), not a eukaryote. Hence the evolutionary history and biology of archaea increasingly comes to bear on eukaryotic origins, more than ever before. Here, we have compiled a survey of endosymbiotic theories for the origin of eukaryotes and mitochondria, and for the origin of the eukaryotic nucleus, summarizing the essentials of each and contrasting some of their predictions to the observations. A new aspect of endosymbiosis in eukaryote evolution comes into focus from these considerations: the host for the origin of plastids was a facultative anaerobe.

  7. Agricultural origins: centers and noncenters.

    PubMed

    Harlan, J R

    1971-10-29

    I propose the theory that agriculture originated independently in three different areas and that, in each case, there was a system composed of a center of origin and a noncenter, in which activities of domestication were dispersed over a span of 5,000 to 10,000 kilometers. One system includes a definable Near East center and a noncenter in Africa; another system includes a North Chinese center and a noncenter in Southeast Asia and the South Pacific; the third system includes a Mesoamerican center and a South American noncenter. There are suggestions that, in each case, the center and noncenter interact with each other. Crops did not necessarily originate in centers (in any conventional concept of the term), nor did agriculture necessarily develop in a geographical "center."

  8. Origin and diversification of eukaryotes.

    PubMed

    Katz, Laura A

    2012-01-01

    The bulk of the diversity of eukaryotic life is microbial. Although the larger eukaryotes-namely plants, animals, and fungi-dominate our visual landscapes, microbial lineages compose the greater part of both genetic diversity and biomass, and contain many evolutionary innovations. Our understanding of the origin and diversification of eukaryotes has improved substantially with analyses of molecular data from diverse lineages. These data have provided insight into the nature of the genome of the last eukaryotic common ancestor (LECA). Yet, the origin of key eukaryotic features, namely the nucleus and cytoskeleton, remains poorly understood. In contrast, the past decades have seen considerable refinement in hypotheses on the major branching events in the evolution of eukaryotic diversity. New insights have also emerged, including evidence for the acquisition of mitochondria at the time of the origin of eukaryotes and data supporting the dynamic nature of genomes in LECA.

  9. [Acute vertigo of neurological origin].

    PubMed

    Bruun, Marie; Højgaard, Joan L Sunnleyg; Kondziella, Daniel

    2013-11-04

    Acute vertigo of neurological origin may be caused by haemorrhages and tumours in the posterior fossa and, most frequently, by ischaemic infarction in the vertebrobasilar circulation. Urgent diagnosis is necessary to avoid further ischaemic episodes, herniation due to cerebellar oedema and/or fatal brainstem infarction. The history should focus on accompanying neurological symptoms. However, vertigo with cerebellar lesions may be monosymptomatic and then bedside evaluation of oculomotor function is the key to correct diagnosis. This paper discusses the pathophysiology, symptomatology and clinical evaluation of acute vertigo of neurological origin.

  10. Fetal origins of cardiovascular disease.

    PubMed

    Barker, D J

    1999-04-01

    Low birthweight, thinness and short body length at birth are now known to be associated with increased rates of cardiovascular disease and non-insulin dependent diabetes in adult life. The fetal origins hypothesis proposes that these diseases originate through adaptations which the fetus makes when it is undernourished. These adaptations may be cardiovascular, metabolic or endocrine. They permanently change the structure and function of the body. Prevention of the diseases may depend on prevention of imbalances in fetal growth or imbalances between prenatal and postnatal growth, or imbalances in nutrient supply to the fetus.

  11. Origin of Water on Mars

    NASA Technical Reports Server (NTRS)

    Lunine, J. I.; Morbidelli, A.; Chambers, J. E.

    2002-01-01

    Dynamical simulations suggest that the Earth's water budget was delivered primarily from the asteroid belt, in the form of large planetary embryos. The same simulations present a very different picture for Mars its water came from a mixture of cometary and small asteroidal bodies. Additional information is contained in the original extended abstract.

  12. The Chemistry of Life's Origin.

    ERIC Educational Resources Information Center

    Ferris, James P.

    1984-01-01

    From an understanding of how the solar system was formed, scientists have determined the conditions under which life probably originated on earth and, by experiment, have demonstrated a number of possible theories. These conditions, experiments, theories, and related topics are discussed. (JN)

  13. Climate Drives Polar Bear Origins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  14. Reflective Practice: Origins and Interpretations

    ERIC Educational Resources Information Center

    Reynolds, Michael

    2011-01-01

    The idea of reflection is central to the theory and practice of learning--especially learning which is grounded in past or current experience. This paper proposes a working definition of reflection and reviews its origins and recent developments. The author also provides an account of "critical reflection", including its rationale and…

  15. The Moon and Its Origin

    ERIC Educational Resources Information Center

    Urey, Harold C.

    1973-01-01

    Describes the origin of the Moon on the basis of the Apollo expeditions as an accumulated gas sphere at its very beginning and, later, a satellite captured by the Earth. Indicates that the model would be substantially believable if further observations should be proved to exist as estimated. (CC)

  16. Interpersonal Feedback: Origins and Applications.

    ERIC Educational Resources Information Center

    Barbour, Alton

    This paper identifies the origins of the concept of feedback and its entry into the interpersonal communication literature as a social science variable. It touches on why feedback might be important in interpersonal relations, what it consists of, some of the relevant research, and some possible dangers or misuses. It speaks to how the process of…

  17. The origin of the Earth.

    PubMed

    Taylor, S R

    1997-01-01

    It is not possible to consider the formation of the Earth in isolation without reference to the formation of the rest of the solar system. A brief account is given of the current scientific consensus on that topic, explaining the origin of an inner solar system rocky planet depleted in most of the gaseous and icy components of the original solar nebula. Volatile element depletion occurred at a very early stage in the nebula, and was probably responsible for the formation of Jupiter before that of the inner planets. The Earth formed subsequently from accumulation of a hierarchy of planetesimals. Evidence of these remains in the ancient cratered surfaces and the obliquities (tilts) of most planets. Earth melting occurred during this process, as well as from the giant Moon-forming impact. The strange density and chemistry of the Moon are consistent with an origin from the mantle of the impactor. Core-mantle separation on the Earth was coeval with accretion. Some speculations are given on the origin of the hydrosphere.

  18. Origin of the 'Extra Entropy'

    NASA Technical Reports Server (NTRS)

    Mushotzky, R.

    2008-01-01

    I will discuss how one can determine the origin of the 'extra entropy' in groups and clusters and the feedback needed in models of galaxy formation. I will stress the use of x-ray spectroscopy and imaging and the critical value that Con-X has in this regard.

  19. The Social Origins of Cancer

    ERIC Educational Resources Information Center

    Randal, Judith

    1976-01-01

    Topics from a September, 1976, symposium on the "Origins of Human Cancer" are cited to illustrate the author's contention that what is needed at such meetings is the scientists' own assessment of the uses to which their work is put in the context of ethics. Their own public commitment is needed to influence public policy. (LBH)

  20. Historical development of origins research.

    PubMed

    Lazcano, Antonio

    2010-11-01

    Following the publication of the Origin of Species in 1859, many naturalists adopted the idea that living organisms were the historical outcome of gradual transformation of lifeless matter. These views soon merged with the developments of biochemistry and cell biology and led to proposals in which the origin of protoplasm was equated with the origin of life. The heterotrophic origin of life proposed by Oparin and Haldane in the 1920s was part of this tradition, which Oparin enriched by transforming the discussion of the emergence of the first cells into a workable multidisciplinary research program. On the other hand, the scientific trend toward understanding biological phenomena at the molecular level led authors like Troland, Muller, and others to propose that single molecules or viruses represented primordial living systems. The contrast between these opposing views on the origin of life represents not only contrasting views of the nature of life itself, but also major ideological discussions that reached a surprising intensity in the years following Stanley Miller's seminal result which showed the ease with which organic compounds of biochemical significance could be synthesized under putative primitive conditions. In fact, during the years following the Miller experiment, attempts to understand the origin of life were strongly influenced by research on DNA replication and protein biosynthesis, and, in socio-political terms, by the atmosphere created by Cold War tensions. The catalytic versatility of RNA molecules clearly merits a critical reappraisal of Muller's viewpoint. However, the discovery of ribozymes does not imply that autocatalytic nucleic acid molecules ready to be used as primordial genes were floating in the primitive oceans, or that the RNA world emerged completely assembled from simple precursors present in the prebiotic soup. The evidence supporting the presence of a wide range of organic molecules on the primitive Earth, including membrane

  1. Historical Development of Origins Research

    PubMed Central

    Lazcano, Antonio

    2010-01-01

    Following the publication of the Origin of Species in 1859, many naturalists adopted the idea that living organisms were the historical outcome of gradual transformation of lifeless matter. These views soon merged with the developments of biochemistry and cell biology and led to proposals in which the origin of protoplasm was equated with the origin of life. The heterotrophic origin of life proposed by Oparin and Haldane in the 1920s was part of this tradition, which Oparin enriched by transforming the discussion of the emergence of the first cells into a workable multidisciplinary research program. On the other hand, the scientific trend toward understanding biological phenomena at the molecular level led authors like Troland, Muller, and others to propose that single molecules or viruses represented primordial living systems. The contrast between these opposing views on the origin of life represents not only contrasting views of the nature of life itself, but also major ideological discussions that reached a surprising intensity in the years following Stanley Miller’s seminal result which showed the ease with which organic compounds of biochemical significance could be synthesized under putative primitive conditions. In fact, during the years following the Miller experiment, attempts to understand the origin of life were strongly influenced by research on DNA replication and protein biosynthesis, and, in socio-political terms, by the atmosphere created by Cold War tensions. The catalytic versatility of RNA molecules clearly merits a critical reappraisal of Muller’s viewpoint. However, the discovery of ribozymes does not imply that autocatalytic nucleic acid molecules ready to be used as primordial genes were floating in the primitive oceans, or that the RNA world emerged completely assembled from simple precursors present in the prebiotic soup. The evidence supporting the presence of a wide range of organic molecules on the primitive Earth, including membrane

  2. 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

  3. The Origin of the Elements

    SciTech Connect

    Murphy, Edward

    2012-11-20

    The world around us is made of atoms. Did you ever wonder where these atoms came from? How was the gold in our jewelry, the carbon in our bodies, and the iron in our cars made? In this lecture, we will trace the origin of a gold atom from the Big Bang to the present day, and beyond. You will learn how the elements were forged in the nuclear furnaces inside stars, and how, when they die, these massive stars spread the elements into space. You will learn about the origin of the building blocks of matter in the Big Bang, and we will speculate on the future of the atoms around us today.

  4. The Origin of the Elements

    ScienceCinema

    Murphy, Edward

    2016-07-12

    The world around us is made of atoms. Did you ever wonder where these atoms came from? How was the gold in our jewelry, the carbon in our bodies, and the iron in our cars made? In this lecture, we will trace the origin of a gold atom from the Big Bang to the present day, and beyond. You will learn how the elements were forged in the nuclear furnaces inside stars, and how, when they die, these massive stars spread the elements into space. You will learn about the origin of the building blocks of matter in the Big Bang, and we will speculate on the future of the atoms around us today.

  5. The Developmental Origins of Osteoporosis

    PubMed Central

    Wood, Claire L; Stenson, Charlotte; Embleton, Nicholas

    2015-01-01

    Osteoporosis is one of the most prevalent skeletal disorders and has enormous public health consequences due to the morbidity and mortality of the resulting fractures. This article discusses the developmental origins of osteoporosis and outlines some of the modifiable and non-modifiable risk factors in both intrauterine and postnatal life that contribute to the later onset of osteoporosis. Evidence for the effects of birth size and early growth in both preterm and term born infants are discussed and the role of epigenetics within the programming hypothesis is highlighted. This review provides compelling evidence for the developmental origins of osteoporosis and highlights the importance of osteoporosis prevention at all stages of the life course. PMID:27018386

  6. The Enigma of Angiosperm Origins

    NASA Astrophysics Data System (ADS)

    Hughes, Norman Francis

    2005-07-01

    The origins of angiosperms are still debated, despite many years of work by scientists from differing disciplines. The progress made toward resolving the problem is reviewed in this book. The author suggests that the only fruitful method of study is the total integrated use of the fossil record, particularly dispersed palynomorphs. This includes the use of electron microscopy and refined data handling to record the occurrence of microscopic fossils, rather than the extensive use of morphology and cladistics. The methods advocated in this book could result in a rethinking of the current classification of living plants, and it is hoped that the ideas presented will initiate discussion between both professionals and students of paleontology and plant science on the wider possibilities that may clarify the enigmatic origins of the dominant flowering plant groups.

  7. The origin of risk aversion

    PubMed Central

    Zhang, Ruixun; Brennan, Thomas J.; Lo, Andrew W.

    2014-01-01

    Risk aversion is one of the most basic assumptions of economic behavior, but few studies have addressed the question of where risk preferences come from and why they differ from one individual to the next. Here, we propose an evolutionary explanation for the origin of risk aversion. In the context of a simple binary-choice model, we show that risk aversion emerges by natural selection if reproductive risk is systematic (i.e., correlated across individuals in a given generation). In contrast, risk neutrality emerges if reproductive risk is idiosyncratic (i.e., uncorrelated across each given generation). More generally, our framework implies that the degree of risk aversion is determined by the stochastic nature of reproductive rates, and we show that different statistical properties lead to different utility functions. The simplicity and generality of our model suggest that these implications are primitive and cut across species, physiology, and genetic origins. PMID:25453072

  8. The Enigma of Angiosperm Origins

    NASA Astrophysics Data System (ADS)

    Hughes, Norman Francis

    1994-09-01

    The origins of angiosperms are still debated, despite many years of work by scientists from differing disciplines. The progress made toward resolving the problem is reviewed in this book. The author suggests that the only fruitful method of study is the total integrated use of the fossil record, particularly dispersed palynomorphs. This includes the use of electron microscopy and refined data handling to record the occurrence of microscopic fossils, rather than the extensive use of morphology and cladistics. The methods advocated in this book could result in a rethinking of the current classification of living plants, and it is hoped that the ideas presented will initiate discussion between both professionals and students of paleontology and plant science on the wider possibilities that may clarify the enigmatic origins of the dominant flowering plant groups.

  9. Determination of plutonium metal origins

    SciTech Connect

    Moody, K.J.

    1995-02-01

    Forensic signatures are present in any Pu sample that can determine the sample`s origin: isotopic ratio of Pu, progeny species that grow into the sample, and contaminant species left over from incomplete purification of the Pu in fuel reprocessing. In the context of intelligence information, this can result in attribution of responsibility for the product of clandestine proliferant operations or material smuggled from existing stockpiles. A list of signature elements and what can be determined from them have been developed. Work needs to be done in converting concentrations of signature species into a quantitative forensic analysis, particularly in regard to reactor performance, but this should require only a small effort. A radiochemical analysis scheme has been developed for measuring these nuclides; more work is needed, particularly for determining fission product concentrations. A sample of Pu metal has been analyzed and several parameters determined that are strong indicators of its point of origin.

  10. Musical Emotions: Functions, Origins, Evolution

    DTIC Science & Technology

    2010-01-01

    27 [93] Perlovsky LI, Kozma R, editors. Neurodynamics of higher-level cognition and consciousness. Heidelberg, Germany: Springer-Verlag; 2006. [94...Perlovsky L, Kozma R. Editorial. Neurodynamics of cognition and consciousness. Heidelberg, Germany: Springer-Verlag; ISBN 978-3-540- 73266-2, 2006. [95...mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of

  11. Swine origin influenza (swine flu).

    PubMed

    Sebastian, Meghna R; Lodha, Rakesh; Kabra, S K

    2009-08-01

    Swine origin influenza was first recognized in the border area of Mexico and United States in April 2009 and during a short span of two months became the first pandemic. The currently circulating strain of swine origin influenza virus of the H1N1 strain has undergone triple reassortment and contains genes from the avian, swine and human viruses. It is transmitted by droplets or fomites. Incubation period is 2 to 7 days. Common clinical symptoms are indistinguishable by any viral respiratory illness, and include fever, cough, sore throat and myalgia. A feature seen more frequently with swine origin influenza is GI upset. Less than 10% of patients require hospitalization. Patients at risk of developing severe disease are - younger than five years, elderly, pregnant women, with chronic systemic illnesses, adolescents on aspirin. Of the severe manifestations of swine origin influenza, pneumonia and respiratory failure are the most common. Unusual symptoms reported are conjunctivitis, parotitis, hemophagocytic syndrome. Infants may present with fever and lethargy with no respiratory symptoms. Diagnosis is based on RT PCR, Viral culture or increasing neutralizing antibodies. Principle of treatment consist of isolation, universal precautions, good infection control practices, supportive care and use of antiviral drugs. Antiviral drugs effective against H1N1 virus include: oseltamivir and zamanavir. With good supportive care case fatality is less than 1%. Preventive measures include: social distancing, practicing respiratory etiquette, hand hygiene and use of chemoprohylaxis with antiviral drugs. Vaccine against H1N1 is not available at present, but will be available in near future.

  12. The origin of lunar craters

    NASA Technical Reports Server (NTRS)

    Wegener, A.

    1975-01-01

    A review is presented of four hypotheses concerning the origin of lunar craters, taking into account the bubble hypothesis, the tide hypothesis, the volcanic hypothesis, and the impact hypothesis. A description is given of a series of experiments on impact craters and studies of a meteorite crater in Arizona are considered. It is concluded that the typical lunar craters can best be interpreted as impact craters.

  13. Origins Space Telescope: Community Participation

    NASA Astrophysics Data System (ADS)

    Carey, Sean J.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its imagers and spectrographs will enable a variety of surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. This poster will outline the ways in which the astronomical community can participate in the STDT activities and a summary of tools that are currently available or are planned for the community during the study. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu.

  14. Hybrid origins of cultivated potatoes.

    PubMed

    Rodríguez, Flor; Ghislain, Marc; Clausen, Andrea M; Jansky, Shelley H; Spooner, David M

    2010-10-01

    Solanum section Petota is taxonomically difficult, partly because of interspecific hybridization at both the diploid and polyploid levels. The taxonomy of cultivated potatoes is particularly controversial. Using DNA sequence data of the waxy gene, we here infer relationships among the four species of cultivated potatoes accepted in the latest taxonomic treatment (S. ajanhuiri, S. curtilobum, S. juzepczukii and S. tuberosum, the latter divided into the Andigenum and Chilotanum Cultivar Groups). The data support prior ideas of hybrid origins of S. ajanhuiri from the S. tuberosum Andigenum Group (2x = S. stenotomum) × S. megistacrolobum; S. juzepczukii from the S. tuberosum Andigenum Group (2x = S. stenotomum) × S. acaule; and S. curtilobum from the S. tuberosum Andigenum Group (4x = S. tuberosum subsp. andigenum) × S. juzepczukii. For the tetraploid cultivar-groups of S. tuberosum, hybrid origins are suggested entirely within much more closely related species, except for two of three examined accessions of the S. tuberosum Chilotanum Group that appear to have hybridized with the wild species S. maglia. Hybrid origins of the crop/weed species S. sucrense are more difficult to support and S. vernei is not supported as a wild species progenitor of the S. tuberosum Andigenum Group.

  15. The origins of medical physics.

    PubMed

    Duck, Francis A

    2014-06-01

    The historical origins of medical physics are traced from the first use of weighing as a means of monitoring health by Sanctorius in the early seventeenth century to the emergence of radiology, phototherapy and electrotherapy at the end of the nineteenth century. The origins of biomechanics, due to Borelli, and of medical electricity following Musschenbroek's report of the Leyden Jar, are included. Medical physics emerged as a separate academic discipline in France at the time of the Revolution, with Jean Hallé as its first professor. Physiological physics flowered in Germany during the mid-nineteenth century, led by the work of Adolf Fick. The introduction of the term medical physics into English by Neil Arnott failed to accelerate its acceptance in Britain or the USA. Contributions from Newton, Euler, Bernoulli, Nollet, Matteucci, Pelletan, Gavarret, d'Arsonval, Finsen, Röntgen and others are noted. There are many origins of medical physics, stemming from the many intersections between physics and medicine. Overall, the early nineteenth-century definition of medical physics still holds today: 'Physics applied to the knowledge of the human body, to its preservation and to the cure of its illnesses'.

  16. Changing ideas about eukaryotic origins.

    PubMed

    Williams, Tom A; Embley, T Martin

    2015-09-26

    The origin of eukaryotic cells is one of the most fascinating challenges in biology, and has inspired decades of controversy and debate. Recent work has led to major upheavals in our understanding of eukaryotic origins and has catalysed new debates about the roles of endosymbiosis and gene flow across the tree of life. Improved methods of phylogenetic analysis support scenarios in which the host cell for the mitochondrial endosymbiont was a member of the Archaea, and new technologies for sampling the genomes of environmental prokaryotes have allowed investigators to home in on closer relatives of founding symbiotic partners. The inference and interpretation of phylogenetic trees from genomic data remains at the centre of many of these debates, and there is increasing recognition that trees built using inadequate methods can prove misleading, whether describing the relationship of eukaryotes to other cells or the root of the universal tree. New statistical approaches show promise for addressing these questions but they come with their own computational challenges. The papers in this theme issue discuss recent progress on the origin of eukaryotic cells and genomes, highlight some of the ongoing debates, and suggest possible routes to future progress.

  17. Origins Space Telescope: Study Plan

    NASA Astrophysics Data System (ADS)

    Cooray, Asantha R.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its spectrographs will enable 3D surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu. This presentation will provide a summary of the OST STDT, the OST Study Team based at NASA Goddard Space Flight Center, study partners, and the advisory panel to the study. This presentation will also summarize recent activities, including the process used to reach a decision on the mission architecture, the identification of key science drivers, and the key study milestones between 2017 and 2020.

  18. Changing ideas about eukaryotic origins

    PubMed Central

    Williams, Tom A.; Embley, T. Martin

    2015-01-01

    The origin of eukaryotic cells is one of the most fascinating challenges in biology, and has inspired decades of controversy and debate. Recent work has led to major upheavals in our understanding of eukaryotic origins and has catalysed new debates about the roles of endosymbiosis and gene flow across the tree of life. Improved methods of phylogenetic analysis support scenarios in which the host cell for the mitochondrial endosymbiont was a member of the Archaea, and new technologies for sampling the genomes of environmental prokaryotes have allowed investigators to home in on closer relatives of founding symbiotic partners. The inference and interpretation of phylogenetic trees from genomic data remains at the centre of many of these debates, and there is increasing recognition that trees built using inadequate methods can prove misleading, whether describing the relationship of eukaryotes to other cells or the root of the universal tree. New statistical approaches show promise for addressing these questions but they come with their own computational challenges. The papers in this theme issue discuss recent progress on the origin of eukaryotic cells and genomes, highlight some of the ongoing debates, and suggest possible routes to future progress. PMID:26323752

  19. The origin of thick discs

    NASA Astrophysics Data System (ADS)

    Comerón, Sébastien

    2015-03-01

    Thick discs are defined to be disc-like components with a scale height larger than that of the classical discs. They are ubiquitous (Yoachim & Dalcanton 2006; Comerón et al. 2011a), they are made of mostly old and metal-poor stars and are most easily detected in close to edge-on galaxies. Their origin has been considered mysterious and several formation theories have been proposed: • The thick disc being formed secularly by thin disc stars heated by disc overdensities such as giant molecular clouds or spiral arms (Villumsen 1985, ApJ, 290, 75) and by stars moved outwards from their original orbits by radial migration mechanisms (Schönrich & Binney 2009). • The thick disc being formed by the heating of the thin disc by satellites (Quinn et al. 1993) and the tidal stripping of them (Abadi et al. 2003). • The thick disc being formed fast and already thick at high redshift in an highly unstable disc. Inside that thick disc, a thin disc would form afterwards as suggested by Elemgreen & Elmegreen (2006). • The thick disc being formed originally thick at high redshift by the merger of gas-rich protogalactic fragments and a thin disc forming afterwards within it (Brook et al. 2007). The first mechanism is a secular evolution mechanism. The time-scale of the second one is dependent on the merger history of the main galaxy. In the two last mechanisms, the thick disc forms already thick in a short time-scale at high redshift. Recent Milky Way studies, (see, e.g., Bovy et al. 2012), have shown indications that there is no discontinuity between the thin and the thick disc chemical and kinematic properties. Instead, those studies indicate the presence of a monotonic distribution of disc thicknesses. This would suggest a secular origin for the Milky Way thick disc. Studies in external galaxies (Yoachim & Dalcanton 2006; Comerón et al. 2011b), have shown that low-mass disc galaxies have thick disc relative masses much larger than those found in large-mass galaxies

  20. 32 CFR 2001.21 - Original classification.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Original classification. 2001.21 Section 2001.21... Markings § 2001.21 Original classification. (a) Primary markings. At the time of original classification... classification markings. See § 2001.24(j) for specific guidance. (e) Date of origin of document. The date...

  1. 32 CFR 2001.21 - Original classification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Original classification. 2001.21 Section 2001.21... Markings § 2001.21 Original classification. (a) Primary markings. At the time of original classification... classification markings. See § 2001.24(j) for specific guidance. (e) Date of origin of document. The date...

  2. 32 CFR 2001.21 - Original classification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Original classification. 2001.21 Section 2001.21... Markings § 2001.21 Original classification. (a) Primary markings. At the time of original classification... classification markings. See § 2001.24(j) for specific guidance. (e) Date of origin of document. The date...

  3. Musical emotions: Functions, origins, evolution

    NASA Astrophysics Data System (ADS)

    Perlovsky, Leonid

    2010-03-01

    Theories of music origins and the role of musical emotions in the mind are reviewed. Most existing theories contradict each other, and cannot explain mechanisms or roles of musical emotions in workings of the mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of the mind has been proposed describing a fundamental role of music in the functioning and evolution of the mind, consciousness, and cultures. The review considers ancient theories of music as well as contemporary theories advanced by leading authors in this field. It addresses one hypothesis that promises to unify the field and proposes a theory of musical origin based on a fundamental role of music in cognition and evolution of consciousness and culture. We consider a split in the vocalizations of proto-humans into two types: one less emotional and more concretely-semantic, evolving into language, and the other preserving emotional connections along with semantic ambiguity, evolving into music. The proposed hypothesis departs from other theories in considering specific mechanisms of the mind-brain, which required the evolution of music parallel with the evolution of cultures and languages. Arguments are reviewed that the evolution of language toward becoming the semantically powerful tool of today required emancipation from emotional encumbrances. The opposite, no less powerful mechanisms required a compensatory evolution of music toward more differentiated and refined emotionality. The need for refined music in the process of cultural evolution is grounded in fundamental mechanisms of the mind. This is why today's human mind and cultures cannot exist without today's music. The reviewed hypothesis gives a basis for future analysis of why different evolutionary paths of languages were paralleled by different evolutionary paths of music. Approaches toward experimental verification of this hypothesis in

  4. Musical emotions: functions, origins, evolution.

    PubMed

    Perlovsky, Leonid

    2010-03-01

    Theories of music origins and the role of musical emotions in the mind are reviewed. Most existing theories contradict each other, and cannot explain mechanisms or roles of musical emotions in workings of the mind, nor evolutionary reasons for music origins. Music seems to be an enigma. Nevertheless, a synthesis of cognitive science and mathematical models of the mind has been proposed describing a fundamental role of music in the functioning and evolution of the mind, consciousness, and cultures. The review considers ancient theories of music as well as contemporary theories advanced by leading authors in this field. It addresses one hypothesis that promises to unify the field and proposes a theory of musical origin based on a fundamental role of music in cognition and evolution of consciousness and culture. We consider a split in the vocalizations of proto-humans into two types: one less emotional and more concretely-semantic, evolving into language, and the other preserving emotional connections along with semantic ambiguity, evolving into music. The proposed hypothesis departs from other theories in considering specific mechanisms of the mind-brain, which required the evolution of music parallel with the evolution of cultures and languages. Arguments are reviewed that the evolution of language toward becoming the semantically powerful tool of today required emancipation from emotional encumbrances. The opposite, no less powerful mechanisms required a compensatory evolution of music toward more differentiated and refined emotionality. The need for refined music in the process of cultural evolution is grounded in fundamental mechanisms of the mind. This is why today's human mind and cultures cannot exist without today's music. The reviewed hypothesis gives a basis for future analysis of why different evolutionary paths of languages were paralleled by different evolutionary paths of music. Approaches toward experimental verification of this hypothesis in

  5. On the Origin of Monsoon

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

    2000-01-01

    It is a long-held fundamental belief that the basic cause of a monsoon is land-sea thermal contrast on the continental scale. Through general circulation model experiments we demonstrate that this belief should be changed. The Asian and Australian summer monsoon circulations are largely intact in an experiment in which Asia, maritime continent, and Australia are replaced by ocean. It is also shown that the change resulting from such replacement is in general due more to the removal of topography than to the removal of land-sea contrast. Therefore, land-sea contrast plays only a minor modifying role in Asian and Australian summer monsoons. This also happens to the Central American summer monsoon. However, the same thing cannot be said of the African and South American summer monsoons. In Asian and Australian winter monsoons land-sea contrast also plays only a minor role. Our interpretation for the origin of monsoon is that the summer monsoon is the result of ITCZ's (intertropical convergence zones) peak being substantially (more than 10 degrees) away from the equator. The origin of the ITCZ has been previously interpreted by Chao. The circulation around thus located ITCZ, previously interpreted by Chao and Chen through the modified Gill solution and briefly described in this paper, explains the monsoon circulation. The longitudinal location of the ITCZs is determined by the distribution of surface conditions. ITCZ's favor locations of higher SST as in western Pacific and Indian Ocean, or tropical landmass, due to land-sea contrast, as in tropical Africa and South America. Thus, the role of landmass in the origin of monsoon can be replaced by ocean of sufficiently high SST. Furthermore, the ITCZ circulation extends into the tropics in the other hemisphere to give rise to the winter monsoon circulation there. Also through the equivalence of land-sea contrast and higher SST, it is argued that the basic monsoon onset mechanism proposed by Chao is valid for all monsoons.

  6. Planetary Origin Evolution and Structure

    NASA Technical Reports Server (NTRS)

    Stevenson, David J.

    2005-01-01

    This wide-ranging grant supported theoretical modeling on many aspects of the formation, evolution and structure of planets and satellites. Many topics were studied during this grant period, including the evolution of icy bodies; the origin of magnetic fields in Ganymede; the thermal histories of terrestrial planets; the nature of flow inside giant planets (especially the coupling to the magnetic field) and the dynamics of silicate/iron mixing during giant impacts and terrestrial planet core formation. Many of these activities are ongoing and have not reached completion. This is the nature of this kind of research.

  7. Origin and History of Magnolias

    NASA Astrophysics Data System (ADS)

    Hebda, R. J.; Irving, E.

    2004-12-01

    The classic disjunct distribution of living magnolias between southeast Asia and the Americas has been a puzzle for more than a century and a half. We propose a scheme for the origin and history of magnolias to explain this distribution by integrating paleogeographic, paleoclimatic, paleobotanical, and phytogeographic data. Our scheme is based on paleomagnetically determined latitudes. We assume that the moist warm temperate climate favoured by most extant magnolias has always been their preference. Molecular analyses (largely chloroplast DNA) reveal that several North American species are distinct and basal forms suggesting that magnolias likely originated in North America, a conclusion supported by the fossil record. We identify four evolutionary stages: (1) Ancestral magnolias originate in the Late Cretaceous of North America in high mid-latitudes (45° -60° N) at low altitudes under greenhouse climates. (2) During the exceptionally warm climate (super-greenhouse) of the Eocene, magnolias spread eastwards via the Iceland-Faroes isthmuses, to Europe and then across west and central Asia possibly to east Asia, still at low altitudes and high mid-latitudes. (3) With global cooling from the mid-Cenozoic, magnolias shift their core range to lower mid-latitudes (30° -45° N), become extinct in Europe and southern Siberia, breaking the once continuous distribution into two. (4) In the late Cenozoic, as ice-house conditions develop, magnolias diversify rapidly and expand southward into moist warm temperate uplands in newly uplifted mountain ranges of South and Central America, southeast Asia and the High Archipelago between southeast Asia and Australia. The late Cenozoic evolution of magnolias is characterized by the impoverishment of northerly species and diversification of southerly species. Thus, the centre of origin is not the center of diversity today. Disjunction at the generic level likely occurred as part of the mid-Tertiary southward displacement of the

  8. Olmec origins of Mesoamerican writing.

    PubMed

    Pohl, Mary E D; Pope, Kevin O; von Nagy, Christopher

    2002-12-06

    A cylinder seal and carved greenstone plaque bearing glyphs dating to approximately 650 B.C. have been uncovered near the Olmec center of La Venta in Tabasco, Mexico. These artifacts, which predate others containing writing, reveal that the key aspects of the Mesoamerican scripts were present in Olmec writing: the combination of pictographic and glyphic elements to represent speech; the use of the sacred 260-day calendar; and the connection between writing, the calendar, and kingship. They imply that Mesoamerican writing originated in the La Venta polity.

  9. New perspectives on anthropoid origins

    PubMed Central

    Williams, Blythe A.; Kay, Richard F.; Kirk, E. Christopher

    2010-01-01

    Adaptive shifts associated with human origins are brought to light as we examine the human fossil record and study our own genome and that of our closest ape relatives. However, the more ancient roots of many human characteristics are revealed through the study of a broader array of living anthropoids and the increasingly dense fossil record of the earliest anthropoid radiations. Genomic data and fossils of early primates in Asia and Africa clarify relationships among the major clades of primates. Progress in comparative anatomy, genomics, and molecular biology point to key changes in sensory ecology and brain organization that ultimately set the stage for the emergence of the human lineage. PMID:20212104

  10. The origin of life at the origin of ageing?

    PubMed

    Currais, Antonio

    2017-05-01

    At first glance, the ageing of unicellular organisms would appear to be different from the ageing of complex, multicellular organisms. In an attempt to describe the nature of ageing in diverse organisms, the intimate links between the origins of life and ageing are examined. Departing from Leslie Orgel's initial ideas on why organisms age, it is then discussed how the potentially detrimental events characteristic of ageing are continuous, cell-autonomous and universal to all organisms. The manifestation of these alterations relies on the balance between their production and cellular renewal. Renewal is achieved not only by repair and maintenance mechanisms but, importantly, by the process of cell division such that every time cells divide ageing-associated effects are diluted.

  11. Origin of marine planktonic cyanobacteria

    PubMed Central

    Sánchez-Baracaldo, Patricia

    2015-01-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600–2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500–542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600–1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000–542 Mya). PMID:26621203

  12. The origin of light hydrocarbons

    NASA Astrophysics Data System (ADS)

    Mango, Frank D.

    2000-04-01

    The light hydrocarbons (LHs) are probably intermediates in the catalytic decomposition of oil to gas: Oil→LHs→Gas Two lines of evidence support this possibility. First, the reaction was duplicated experimentally under moderate conditions. Second, natural LHs exhibit the characteristics of catalytic products, in particular a proportionality between isomers: (xyi)/(xiy)=α (where x and xi are isomers; y and yi are isomers that are structurally similar to x and xi; and α is a constant). All oils exhibit this relationship with coefficients of correlation reaching 0.99. Isomer ratios change systematically with concentrations, some approaching thermodynamic equilibrium, others not. The correlations reported are the strongest yet disclosed for the LHs. Isomers are related in triads (e.g., n-hexane ↔ 2-methylpentane ↔ 3-methylpentane), consistent with cyclopropane precursors. The LHs obtained experimentally are indistinguishable from natural LHs in (xyi)/(xiy). These relationships are not explained by physical fractionations, equilibrium control, or noncatalytic modes of origin. A catalytic origin, on the other hand, has precedence, economy and experimental support.

  13. The origins of modern divorce.

    PubMed

    Coontz, Stephanie

    2007-03-01

    High rates of marital dissolution and easy access to divorce are not unprecedented, historically or cross-culturally. But contemporary divorce in North America and Western Europe has different origins and features than divorce in previous cultures. The origins of modern divorce patterns date back more than 200 years, to the invention of the historically unprecedented idea that marriage should be based on love and mutual affection. Ironically, then, the fragility of modern marriage stems from the same values that have elevated the marital relationship above all other personal and familial commitments: the concentration of emotion, passion, personal identity, and self-validation in the couple relationship and the attenuation of emotional attachments and obligations beyond the conjugal unit. The immediate causes of divorce may range from factors as diverse as the personal psychological characteristics of one or both spouses to the stresses of economic hardship and community disintegration. But in a larger perspective, the role of divorce in modern societies and its relatively high occurrence both flow from the same complex of factors that have made good marriages so much more central to people's happiness than through most of the past, and deterioration of a marital relationship so much more traumatic.

  14. Ancient origin of mast cells

    PubMed Central

    Wong, G. William; Zhuo, Lisheng; Kimata, Koji; Lam, Bing K.; Satoh, Nori; Stevens, Richard L.

    2014-01-01

    The sentinel roles of mammalian mast cells (MCs) in varied infections raised the question of their evolutionary origin. We discovered that the test cells in the sea squirt Ciona intestinalis morphologically and histochemically resembled cutaneous human MCs. Like the latter, C. intestinalis test cells stored histamine and varied heparin•serine protease complexes in their granules. Moreover, they exocytosed these preformed mediators when exposed to compound 48/80. In support of the histamine data, a C. intestinalis-derived cDNA was isolated that resembled that which encodes histidine decarboxylase in human MCs. Like heparin-expressing mammalian MCs, activated test cells produced prostaglandin D2 and contained cDNAs that encode a protein that resembles the synthase needed for its biosynthesis in human MCs. The accumulated morphological, histochemical, biochemical, and molecular biology data suggest that the test cells in C. intestinalis are the counterparts of mammalian MCs that reside in varied connective tissues. The accumulated data point to an ancient origin of MCs that predates the emergence of the chordates >500 million years ago, well before the development of adaptive immunity. The remarkable conservation of MCs throughout evolution is consistent with their importance in innate immunity. PMID:25094046

  15. Origin of marine planktonic cyanobacteria.

    PubMed

    Sánchez-Baracaldo, Patricia

    2015-12-01

    Marine planktonic cyanobacteria contributed to the widespread oxygenation of the oceans towards the end of the Pre-Cambrian and their evolutionary origin represents a key transition in the geochemical evolution of the Earth surface. Little is known, however, about the evolutionary events that led to the appearance of marine planktonic cyanobacteria. I present here phylogenomic (135 proteins and two ribosomal RNAs), Bayesian relaxed molecular clock (18 proteins, SSU and LSU) and Bayesian stochastic character mapping analyses from 131 cyanobacteria genomes with the aim to unravel key evolutionary steps involved in the origin of marine planktonic cyanobacteria. While filamentous cell types evolved early on at around 2,600-2,300 Mya and likely dominated microbial mats in benthic environments for most of the Proterozoic (2,500-542 Mya), marine planktonic cyanobacteria evolved towards the end of the Proterozoic and early Phanerozoic. Crown groups of modern terrestrial and/or benthic coastal cyanobacteria appeared during the late Paleoproterozoic to early Mesoproterozoic. Decrease in cell diameter and loss of filamentous forms contributed to the evolution of unicellular planktonic lineages during the middle of the Mesoproterozoic (1,600-1,000 Mya) in freshwater environments. This study shows that marine planktonic cyanobacteria evolved from benthic marine and some diverged from freshwater ancestors during the Neoproterozoic (1,000-542 Mya).

  16. On the origin of life.

    PubMed

    Szostak, Jack W

    The origin of life is a very rich field, filled with possibilities and ripe for discovery. RNA replication requires chemical energy and vesicle division is easy to do with mechanical energy. These requirements point to a surface lake, perhaps at some time following the period of concentrated cyanide chemistry that gave rise to nucleotides, amino acids and (maybe) fatty acids. A second requirement follows specifically from the nature of the RNA replication cycle, which requires generally cool to moderate temperatures for the copying chemistry, punctuated by brief periods of high temperature for strand separation. Remarkably, lakes in a geothermal active area provide just such a fluctuating temperature environment, because lakes similar to Yellowstone can be generally cool (even ice covered in winter), but they contain numerous hydrothermal vents that emit streams of hot water. Protocells in such an environment would occasionally be swept into these hot water streams, where the transient high temperature exposure would cause RNA strand separation. However, the protocells would be quickly mixed with surrounding cold water, and would therefore cool quickly, before their delicate RNA molecules could be destroyed by heat. Because of the combination of favorable chemical and physical environments, this could be the most likely scenario for the early Earth environment that nurtured the origin of life.

  17. The origin of light hydrocarbons

    SciTech Connect

    Mango, F.D.

    2000-04-01

    The light hydrocarbons (LHs) are probably intermediates in the catalytic decomposition of oil to gas. Two lines of evidence support this possibility. First, the reaction was duplicated experimentally under moderate conditions. Second, natural LHs exhibit the characteristics of catalytic products, in particular a proportionality between isomers: (xy{sub i})/(x{sub i}y) = {alpha} (where x and x{sub i} are isomers; y and y{sub i} are isomers that are structurally similar to x and x{sub i}; and {alpha} is a constant). All oils exhibit this relationship with coefficients of correlation reaching 0.99. Isomer ratios change systematically with concentrations, some approaching thermodynamic equilibrium, others not. The correlations reported are the strongest yet disclosed for the LHs. Isomers are related in triads (e.g., n-hexane {leftrightarrow} 2-methylpentane {leftrightarrow} 3-methylpentane), consistent with cyclopropane precursors. The LHs obtained experimentally are indistinguishable from natural LHs in (xy{sub i})/(x{sub i}y). These relationships are not explained by physical fractionations, equilibrium control, or noncatalytic modes of origin. A catalytic origin, on the other hand, has precedence, economy and experimental support.

  18. Origins of narcissism in children.

    PubMed

    Brummelman, Eddie; Thomaes, Sander; Nelemans, Stefanie A; Orobio de Castro, Bram; Overbeek, Geertjan; Bushman, Brad J

    2015-03-24

    Narcissism levels have been increasing among Western youth, and contribute to societal problems such as aggression and violence. The origins of narcissism, however, are not well understood. Here, we report, to our knowledge, the first prospective longitudinal evidence on the origins of narcissism in children. We compared two perspectives: social learning theory (positing that narcissism is cultivated by parental overvaluation) and psychoanalytic theory (positing that narcissism is cultivated by lack of parental warmth). We timed the study in late childhood (ages 7-12), when individual differences in narcissism first emerge. In four 6-mo waves, 565 children and their parents reported child narcissism, child self-esteem, parental overvaluation, and parental warmth. Four-wave cross-lagged panel models were conducted. Results support social learning theory and contradict psychoanalytic theory: Narcissism was predicted by parental overvaluation, not by lack of parental warmth. Thus, children seem to acquire narcissism, in part, by internalizing parents' inflated views of them (e.g., "I am superior to others" and "I am entitled to privileges"). Attesting to the specificity of this finding, self-esteem was predicted by parental warmth, not by parental overvaluation. These findings uncover early socialization experiences that cultivate narcissism, and may inform interventions to curtail narcissistic development at an early age.

  19. Primary hypersomnias of central origin.

    PubMed

    Frenette, Eric; Kushida, Clete A

    2009-09-01

    Hypersomnia is a frequently encountered symptom in clinical practice. The cardinal manifestation is inappropriate daytime sleepiness, common to all types of hypersomnias. Hypersomnias of central origin are a rare cause of excessive daytime sleepiness, much rarer than the hypersomnia related to other pathologies, such as sleep-disordered breathing. Narcolepsy, with or without cataplexy, remains the most well studied of the primary hypersomnias. Although recognized more than a century ago, it was not until the end of the 20th century that major breakthroughs led to a better understanding of the disease, with hope of more specific therapies. The authors review the major aspects of this disorder, including the newer treatment modalities. Idiopathic hypersomnia is also part of the primary hypersomnias. Although difficult to diagnose, certain peculiarities stand out to help us differentiate it from the more commonly seen narcolepsy. The recurrent hypersomnias, particularly the Kleine-Levin syndrome, will be discussed. This rare disorder has been studied more closely in the last few years with abundant epidemiologic data assembled through literature and worldwide case reviews. Understanding the primary central hypersomnias warrants a thorough look from the original description, as well as a peek at the future, while more efficacious diagnostic and therapeutic interventions are currently being developed.

  20. The Origin of Cosmic Rays

    ScienceCinema

    Blasi, Pasquale [INAF/Arcetri-Italy and Fermilab, Italy

    2016-07-12

    Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the “end” of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform “cosmic ray astronomy”, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

  1. Geochemical Origin of Biological Molecules

    NASA Astrophysics Data System (ADS)

    Bassez, Marie-Paule

    2013-04-01

    A model for the geochemical origin of biological molecules is presented. Rocks such as peridotites and basalts, which contain ferromagnesian minerals, evolve in the presence of water. Their hydrolysis is an exothermic reaction which generates heat and a release of H2 and of minerals with modified structures. The hydrogen reacts with the CO2 embedded inside the rock or with the CO2 of the environment to form CO in an hydrothermal process. With the N2 of the environment, and with an activation source arising from cosmic radiation, ferromagnesian rocks might evolve towards the abiotic formation of biological molecules, such as peptide like macromolecules which produce amino acids after acid hydrolysis. The reactions concerned are described. The production of hydrothermal CO is discussed in geological sites containing ferromagnesian silicate minerals and the low intensity of the Earth's magnetic field during Paleoarchaean Era is also discussed. It is concluded that excitation sources arising from cosmic radiation were much more abundant during Paleoarchaean Era and that macromolecular structures of biological relevance might consequently form during Archaean Eon, as a product of the chemical evolution of the rocks and of their mineral contents. This synthesis of abiotically formed biological molecules is consecutively discussed for meteorites and other planets such as Mars. This model for the geochemical origin of biological molecules has first been proposed in 2008 in the context of reactions involving catalysers such as kaolinite [Bassez 2008a] and then presented in conferences and articles [Bassez 2008b, 2009, 2012; Bassez et al. 2009a to 2012b]. BASSEZ M.P. 2008a Synthèse prébiotique dans les conditions hydrothermales, CNRIUT'08, Lyon 29-30/05/2008, Conf. and open access article:http://liris.cnrs.fr/~cnriut08/actes/ 29 mai 11h-12h40. BASSEZ M.P. 2008b Prebiotic synthesis under hydrothermal conditions, ISSOL'08, P2-6, Firenze-Italy, 24-29/08/2008. Poster at the

  2. Origins and Evolution of Life

    NASA Astrophysics Data System (ADS)

    Gargaud, Muriel; López-García, Purificación; Martin, Hervé

    2011-01-01

    Part I. What Is Life?: 1. Problems raised by a definition of life M. Morange; 2. Some remarks about uses of cosmological anthropic 'principles' D. Lambert; 3. Minimal cell: the biologist point of view C. Brochier-Armanet; 4. Minimal cell: the computer scientist point of view H. Bersini; 5. Origins of life: computing and simulation approaches B. Billoud; Part II. Astronomical and Geophysical Context of the Emergence of Life: 6. Organic molecules in interstellar medium C. Ceccarelli and C. Cernicharo; 7. Cosmochemical evolution and the origin of life: insights from meteorites S. Pizzarello; 8. Astronomical constraints on the emergence of life M. Gounelle and T. Montmerle; 9. Formation of habitable planets J. Chambers; 10. The concept of galactic habitable zone N. Prantzos; 11. The young Sun and its influence on planetary atmospheres M. Güdel and J. Kasting; 12. Climates of the Earth G. Ramstein; Part III. Role of Water in the Emergence of Life: 13. Liquid water: a necessary condition to all forms of life K. Bartik, G. Bruylants, E. Locci and J. Reisse; 14. The role of water in the formation and evolution of planets T. Encrenaz; 15. Water on Mars J. P. Bibring; Part IV. From Non-Living Systems to Life: 16. Energetic constraints on prebiotic pathways: application to the emergence of translation R. Pascal and L. Boiteau; 17. Comparative genomics and early cell evolution A. Lazcano; 18. Origin and evolution of metabolisms J. Peretó; Part V. Mechanisms for Life Evolution: 19. Molecular phylogeny: inferring the patterns of evolution E. Douzery; 20. Horizontal gene transfer: mechanisms and evolutionary consequences D. Moreira; 21. The role of symbiosis in eukaryotic evolution A. Latorre, A. Durbán, A. Moya and J. Peretó; Part VI. Life in Extreme Conditions: 22. Life in extreme conditions: Deinococcus radiodurans, an organism able to survive prolonged desiccation and high doses of ionising radiation S. Sommer and M. Toueille; 23. Molecular effects of UV and ionizing

  3. Bacterial Influences on Animal Origins

    PubMed Central

    Alegado, Rosanna A.; King, Nicole

    2014-01-01

    Animals evolved in seas teeming with bacteria, yet the influences of bacteria on animal origins are poorly understood. Comparisons among modern animals and their closest living relatives, the choanoflagellates, suggest that the first animals used flagellated collar cells to capture bacterial prey. The cell biology of prey capture, such as cell adhesion between predator and prey, involves mechanisms that may have been co-opted to mediate intercellular interactions during the evolution of animal multicellularity. Moreover, a history of bacterivory may have influenced the evolution of animal genomes by driving the evolution of genetic pathways for immunity and facilitating lateral gene transfer. Understanding the interactions between bacteria and the progenitors of animals may help to explain the myriad ways in which bacteria shape the biology of modern animals, including ourselves. PMID:25280764

  4. The origin of electrochemical nomenclature.

    PubMed

    Giddens, W R

    2001-09-01

    This article is about the origin and development of certain words that are important in the vocabulary of all physicians and scientists. The words that make up the electrochemical nomenclature were created in 1833 by Michael Faraday and several of his friends. Terms such as electrolyte, ion, and electrode were invented in a fashion that ignored theory but fitted the experimental facts of the laboratory. This nomenclature, derived from Greek, was so accurate and functional that is has been completely incorporated into modern chemistry, a fact that seems remarkable since the structure of the atom was completely unknown at the time. To fully develop the etymology of these words, the life of Faraday is summarized and the deliberations of the men involved are reviewed.

  5. Origins of life systems chemistry

    NASA Astrophysics Data System (ADS)

    Sutherland, J.

    2015-10-01

    By reconciling previously conflicting views about the origin of life - in which one or other cellular subsystem emerges first, and then 'invents' the others - a new modus operandi for its study is suggested. Guided by this, a cyanosulfidic protometabolism is uncovered which uses UV light and the stoichiometric reducing power of hydrogen sulfide to convert hydrogen cyanide, and a couple of other prebiotic feedstock molecules which can be derived therefrom, into nucleic acid, peptide and lipid building blocks. Copper plays several key roles in this chemistry, thus, for example, copper(I) catalysed cross coupling and copper(II) driven oxidative crosscoupling reactions generate key feedstock molecules. Geochemical scenarios consistent with this protometabolism are outlined. Finally, the transition of a system from the inanimate to the animate state is considered in the context of there being intermediate stages of partial 'aliveness'.

  6. The origin of Lotus corniculatus.

    PubMed

    Ross, M D; Jones, W T

    1985-12-01

    Earlier students of the origin of Lotus corniculatus suggested that this tetraploid species arose as an autotetraploid of the closely related diploid species L. tenuis or L. alpinus. More recent studies suggested that L. alpinus and L. japonicus could be ancestral forms. The present study of tannin content, phenolic content, cyanide production, morphology, cytogenetics, Rhizobium specificity and self-incompatibility in the corniculatus group virtually excludes the possibility that L. corniculatus could have arisen through autopolyploidy of L. tenuis or L. alpinus, and suggests that L. corniculatus arose through hybridization of L. alpinus and/or L. tenuis (probably as female parent) with L. uliginosus (probably as male parent), followed by chromosome doubling in the hybrid.

  7. [The origin of hypertrophic cardiomyopathy].

    PubMed

    Moiseev, V S

    1985-01-01

    The author describes the clinical cases of hypertrophic cardiomyopathy (CMP). The development of obstructive CMP in a patient with hyperparathyroidism indicates a possible pathogenetic role of endocrine factors and calcium metabolism abnormalities. The familial character of the disease and its combination with hereditary diseases (familial microspherocytosis) point to the significance of genetic factors. In addition, marked hypertrophy of the myocardium (without dilatation) including hypertrophy with obstruction of the outflow tract of the left ventricle was observed in nonspecific protracted myocarditis, alcoholic injury to the heart, in athletes, in coronary heart disease (after survival of myocardial infarction). It is suggested that hypertrophic CMP (similarly to restrictive and congestive CMP) is most likely a syndrome of varying origin.

  8. Photorespiration: players, partners and origin.

    PubMed

    Bauwe, Hermann; Hagemann, Martin; Fernie, Alisdair R

    2010-06-01

    Photorespiratory metabolism allows plants to thrive in a high-oxygen containing environment. This metabolic pathway recycles phosphoglycolate, a toxic compound, back to phosphoglycerate, when oxygen substitutes for carbon dioxide in the first reaction of photosynthetic carbon fixation. The recovery of phosphoglycerate is accompanied by considerable carbon and energy losses, making photorespiration a prime target for crop improvement. The genomics era has allowed the precise functional analysis of individual reaction steps of the photorespiratory cycle, and more links integrating photorespiration with cellular metabolism as a whole are becoming apparent. Here we review the evolutionary origins of photorespiration as well as new insights into the interaction with other metabolic processes such as nitrogen assimilation and mitochondrial respiration.

  9. The origin of cellular life

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.

    2000-01-01

    This essay presents a scenario of the origin of life that is based on analysis of biological architecture and mechanical design at the microstructural level. My thesis is that the same architectural and energetic constraints that shape cells today also guided the evolution of the first cells and that the molecular scaffolds that support solid-phase biochemistry in modern cells represent living microfossils of past life forms. This concept emerged from the discovery that cells mechanically stabilize themselves using tensegrity architecture and that these same building rules guide hierarchical self-assembly at all size scales (Sci. Amer 278:48-57;1998). When combined with other fundamental design principles (e.g., energy minimization, topological constraints, structural hierarchies, autocatalytic sets, solid-state biochemistry), tensegrity provides a physical basis to explain how atomic and molecular elements progressively self-assembled to create hierarchical structures with increasingly complex functions, including living cells that can self-reproduce.

  10. Brain abscess of odontogenic origin.

    PubMed

    Antunes, Antonio Azoubel; de Santana Santos, Thiago; de Carvalho, Ricardo Wathson Feitosa; Avelar, Rafael Linard; Pereira, Carlos Umberto; Pereira, José Carlos

    2011-11-01

    Brain abscess is a rare and threatening infection, which is in a suppuration area, caused either by trauma, neurosurgical complication, or by a secondary infection of dental origin complication. The infectious process spread from the start focus can occur in 2 ways: hematogenous or by contiguity. The treatment should ideally be based on the etiological factor excision, combined with drainage and antibiotics as adjuvant; this philosophy is not observed in the reports described in the 1960s, 1970s, and 1980s. This study's goal was to report a case of brain abscess consequent of an odontogenic outbreak, where an adequate treatment was set up, but it was already in advanced stages and had as a result the lethal outcome. Complications from the odontogenic infections have a low incidence, but should never be disregarded, because they can lead to death, as described in this manuscript.

  11. Impact origin of the Moon

    SciTech Connect

    Slattery, W.L.

    1998-12-31

    A few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored.

  12. 5 CFR 2500.3 - Original classification.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2500.3 Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT INFORMATION SECURITY REGULATION § 2500.3 Original classification. No one in the Office of Administration has been granted authority for original classification of information....

  13. The interplanetary superhighway and the Origins Program

    NASA Technical Reports Server (NTRS)

    Lo, M. W.

    2002-01-01

    The origin of the universe and of life itself have been central to human inquiries since the dawn of consciousness. To develop and use the technologies to answer these timeless and profound questions is the mission of NASA's Origins Program.

  14. The Origin of the Chemical Elements, 1

    ERIC Educational Resources Information Center

    Selbin, Joel

    1973-01-01

    The problem of the origin is inextricably interwoven with such matters as the origin of the universe, the structure and evolution of galaxies, stars and other astronomical objects, and with nuclear physics. (Author/DF)

  15. 5 CFR 2500.3 - Original classification.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2500.3 Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT INFORMATION SECURITY REGULATION § 2500.3 Original classification. No one in the Office of Administration has been granted authority for original classification of information....

  16. 5 CFR 2500.3 - Original classification.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2500.3 Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT INFORMATION SECURITY REGULATION § 2500.3 Original classification. No one in the Office of Administration has been granted authority for original classification of information....

  17. 5 CFR 2500.3 - Original classification.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2500.3 Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT INFORMATION SECURITY REGULATION § 2500.3 Original classification. No one in the Office of Administration has been granted authority for original classification of information....

  18. 5 CFR 2500.3 - Original classification.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2500.3 Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT INFORMATION SECURITY REGULATION § 2500.3 Original classification. No one in the Office of Administration has been granted authority for original classification of information....

  19. Reassessing the origin of Triton

    NASA Astrophysics Data System (ADS)

    Nogueira, E.; Brasser, R.; Gomes, R.

    2011-07-01

    The origin of Neptune's large, circular but retrograde satellite Triton has remained largely unexplained. There is an apparent consensus that its origin lies in it being captured, but until recently no successful capture mechanism has been found. Agnor and Hamilton (Agnor, C.B., Hamilton, D.P. [2006]. Nature 441, 192-194) demonstrated that the disruption of a trans-neptunian binary object which had Triton as a member, and which underwent a very close encounter with Neptune, was an effective mechanism to capture Triton while its former partner continued on a hyperbolic orbit. The subsequent evolution of Triton's post-capture orbit to its current one could have proceeded through gravitational tides (Correia, A.C.M. [2009]. Astrophys. J. 704, L1-L4), during which time Triton was most likely semi-molten (McKinnon, W.B. [1984]. Nature 311, 355-358). However, to date, no study has been performed that considered both the capture and the subsequent tidal evolution. Thus it is attempted here with the use of numerical simulations. The study by Agnor and Hamilton (Agnor, C.B., Hamilton, D.P. [2006]. Nature 441, 192-194) is repeated in the framework of the Nice model (Tsiganis, K., Gomes, R., Morbidelli, A., Levison, H.F. [2005]. Nature 435, 459-461) to determine the post-capture orbit of Triton. After capture Triton is then subjected to tidal evolution using the model of Mignard (Mignard, F. [1979]. Moon Planets 20, 301-315; Mignard, F. [1980]. Moon Planets 23, 185-201). The perturbations from the Sun and the figure of Neptune are included. The perturbations from the Sun acting on Triton just after its capture cause it to spend a long time in its high-eccentricity phase, usually of the order of 10 Myr, while the typical time to circularise to its current orbit is some 200 Myr, consistent with earlier studies. The current orbit of Triton is consistent with an origin through binary capture and tidal evolution, even though the model prefers Triton to be closer to Neptune than it

  20. Ambient neutrons of natural origin

    NASA Astrophysics Data System (ADS)

    Gusev, Anatoly; Martin, Inacio; Shkevov, Rumen; Alves, Mauro

    2016-07-01

    The laboratory of environmental radiation of ITA (São José dos Campos, 23°11'11″S, 45°52'43″W, 650 MAMSL) performs simultaneous monitoring of a natural radiation background and meteorological parameters. Neutron flux in the energy range of 0.02 eV - 10 MeV is registered with two sets of proportional ^{3}He tubes placed into cylindrical paraffin thermalizers: an {bf outdoor detector }of 250 cm² area and {bf indoor detector }of 70 cm² area located on the second floor of a concrete building. The counter efficiency for thermal neutrons is 80%. The characteristics of the observed flux variation are quite different from those inherent to the neutrons of the cosmic ray origin. {bf Four types of the outdoor flux variations }are observed: 1) {bf seasonal }with a maxima in wet seasons; 2) {bf diurnal }with maximum at about 6 h local time and an amplitude up to several dozens; 3) {bf abrupt transient} ( 1 min) increases with magnitudes up to two orders higher than the mean daily flux; 4) short (several days) {bf quasi-periodic enhancements }with amplitudes up to several times higher than the mean daily flux. A large variation of the outdoor flux and its phase synchronism with that of the radon decay products means with a high probability their common origin. An apparent source of the neutrons observed is nuclear reactions of decay α-particles with the ground matter. In this case the dynamics of the outdoor flux variations of the first two types is controlled by those of the meteorological parameters in the locality. The third type events correlate with lightning strokes in the vicinity (<200 m) of the detector. The more rare fourth type correlate neither with geomagnetic disturbances nor with meteorological phenomena and are probably a result of natural radon release from the Earth's crust triggered by minor seismological activity. The indoor flux is quite stable with a possible weak maximum at16 h not exceeding 0.1.

  1. [Viral hepatitis of enteric origin].

    PubMed

    Debord, T; Buisson, Y

    1998-01-01

    Hepatitis viruses of oral-fecal origin are responsible for a high morbidity and mortality throughout the world, even if they never result in chronic hepatitis. Two viruses, the virus of hepatitis A (VHA) and of hepatitis E (VHE) are at present the cause of severe viral hepatitis of enteric origin. Water is the principle vector in the spread of these viruses. However, the epidemiological aspects vary according to the pathogenic agent. VHA is excreted in a highly concentrated form in the feces for a relatively short period of time. Since it resists in an exterior environment, the virus remains infectious for a long time. VHE is excreted for a short period of time and in low concentrations. The viral particles are fragile in vitro and their variability in the environment is little known. The possible reservoir role of certain animals has been envisaged. Epidemics arise especially in countries suffering from poor hygiene and massive water pollution. Hepatitis A should no longer be considered a benign disease of childhood. The progress made in hygiene and economic development in industrialized countries have made contacts with this virus scarce, rendering the populations more receptive to it and epidemics more widespread. When the sickness occurs later in life, infection is more often symptomatic and can be serious, resulting sometimes long-term indisposition. Hepatitis E has a vast distribution throughout the world and manifests itself either in epidemic or endemic-sporadic form in many poor countries. In developed countries, it comes about mostly as a result of imported pathology, even if there exists a "substratum" of infection in these areas. The main clinical aspects, such as we were able to study them in 39 cases of military men from Tchad, Guyana and Somalia, are comparable to those of hepatitis A. The reasons for the particular gravity of symptoms in pregnant women are unknown. These affections have no specific treatment. In the field of prevention, vaccination

  2. Origin and development of muscle cramps.

    PubMed

    Minetto, Marco Alessandro; Holobar, Aleš; Botter, Alberto; Farina, Dario

    2013-01-01

    Cramps are sudden, involuntary, painful muscle contractions. Their pathophysiology remains poorly understood. One hypothesis is that cramps result from changes in motor neuron excitability (central origin). Another hypothesis is that they result from spontaneous discharges of the motor nerves (peripheral origin). The central origin hypothesis has been supported by recent experimental findings, whose implications for understanding cramp contractions are discussed.

  3. Darwin's Book: On the Origin of Species

    NASA Astrophysics Data System (ADS)

    Hodge, Jonathan

    2013-09-01

    This essay is an interpretation of Charles Darwin's Origin of Species. It focuses on the contents of the Origin as Darwin intended them to be understood and the background to the work, thus revealing the originality (or otherwise) of the work.

  4. 7 CFR 201.14 - Origin.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Labeling Agricultural Seeds § 201.14 Origin. (a) Alfalfa, red clover, white clover, and field corn (except hybrid seed corn) shall be labeled to show: (1) The origin, if known; or (2) if the origin is not...

  5. Becoming Original: Effects of Strategy Instruction

    ERIC Educational Resources Information Center

    van de Kamp, Marie-Thérèse; Admiraal, Wilfried; Rijlaarsdam, Gert

    2016-01-01

    Visual arts education focuses on creating original visual art products. A means to improve originality is enhancement of divergent thinking, indicated by fluency, flexibility and originality of ideas. In regular arts lessons, divergent thinking is mostly promoted through brainstorming. In a previous study, we found positive effects of an explicit…

  6. The Origins of Competency-Based Training

    ERIC Educational Resources Information Center

    Hodge, Steven

    2007-01-01

    This article attempts to trace the origins of competency-based training (CBT), the theory of vocational education that underpins the National Training Framework in Australia. A distinction is made between societal and theoretical origins. This paper argues that CBT has its societal origins in the United States of America during the 1950s, 60s and…

  7. Morphogenetic origin of natural variation.

    PubMed

    Cherdantsev, Vladimir G; Scobeyeva, Victoria A

    2012-09-01

    We studied individual pathways of gastrulation in two related amphibian species making an emphasis on the developmental dynamics of normal variation in the geometry of gastrulation movements. Analyzing the variation dynamics, we show that the linear succession of developmental stages is a secondary phenomenon disguising self-oscillations that lie at the heart of the dorsal blastopore lip morphogenesis. Characteristic features of the equations derived to describe the oscillations are, first, their dependence only on the movement geometry and, second, including of the dynamics of spatial variance directly into the movement equations, making it clear that the reasons for variability of morphogenesis are the same that for morphogenesis itself. The equations describing morphogenetic oscillations are mathematically similar to those describing natural selection in that the system tends to minimize its variance, individual or within-individual one, but the spatially uniform state turns to be unstable. Comparing of the dynamics of natural developmental variation in gastrulation in two frog species shows that, depending on the mechanics and geometry mass cell movements, different types of gastrulation movements have different proportions of the between- to within-individual differences, which strongly influences the choice of characters subject to evolution. Instead of being a source of constraints imposed on externally guided evolutionary trends, morphogenesis becomes a driving force of the adaptively silent, but directional evolution of the developing systems, which seems to be the only possible way of originating of the evolutionary novelties, both in evolution and ontogeny of the biological structures.

  8. Human origins: Out of Africa

    PubMed Central

    Tattersall, Ian

    2009-01-01

    Our species, Homo sapiens, is highly autapomorphic (uniquely derived) among hominids in the structure of its skull and postcranial skeleton. It is also sharply distinguished from other organisms by its unique symbolic mode of cognition. The fossil and archaeological records combine to show fairly clearly that our physical and cognitive attributes both first appeared in Africa, but at different times. Essentially modern bony conformation was established in that continent by the 200–150 Ka range (a dating in good agreement with dates for the origin of H. sapiens derived from modern molecular diversity). The event concerned was apparently short-term because it is essentially unanticipated in the fossil record. In contrast, the first convincing stirrings of symbolic behavior are not currently detectable until (possibly well) after 100 Ka. The radical reorganization of gene expression that underwrote the distinctive physical appearance of H. sapiens was probably also responsible for the neural substrate that permits symbolic cognition. This exaptively acquired potential lay unexploited until it was “discovered” via a cultural stimulus, plausibly the invention of language. Modern humans appear to have definitively exited Africa to populate the rest of the globe only after both their physical and cognitive peculiarities had been acquired within that continent. PMID:19805256

  9. Endosymbiotic theory for organelle origins.

    PubMed

    Zimorski, Verena; Ku, Chuan; Martin, William F; Gould, Sven B

    2014-12-01

    Endosymbiotic theory goes back over 100 years. It explains the similarity of chloroplasts and mitochondria to free-living prokaryotes by suggesting that the organelles arose from prokaryotes through (endo)symbiosis. Gene trees provide important evidence in favour of symbiotic theory at a coarse-grained level, but the finer we get into the details of branches in trees containing dozens or hundreds of taxa, the more equivocal evidence for endosymbiotic events sometimes becomes. It seems that either the interpretation of some endosymbiotic events are wrong, or something is wrong with the interpretations of some gene trees having many leaves. There is a need for evidence that is independent of gene trees and that can help outline the course of symbiosis in eukaryote evolution. Protein import is the strongest evidence we have for the single origin of chloroplasts and mitochondria. It is probably also the strongest evidence we have to sort out the number and nature of secondary endosymbiotic events that have occurred in evolution involving the red plastid lineage. If we relax our interpretation of individual gene trees, endosymbiotic theory can tell us a lot.

  10. On the Origin of Sequence

    PubMed Central

    van der Gulik, Peter T. S.

    2015-01-01

    Three aspects which make planet Earth special, and which must be taken in consideration with respect to the emergence of peptides, are the mineralogical composition, the Moon which is in the same size class, and the triple environment consisting of ocean, atmosphere, and continent. GlyGly is a remarkable peptide because it stimulates peptide bond formation in the Salt-Induced Peptide Formation reaction. The role glycine and aspartic acid play in the active site of RNA polymerase is remarkable too. GlyGly might have been the original product of coded peptide synthesis because of its importance in stimulating the production of oligopeptides with a high aspartic acid content, which protected small RNA molecules by binding Mg2+ ions. The feedback loop, which is closed by having RNA molecules producing GlyGly, is proposed as the essential element fundamental to life. Having this system running, longer sequences could evolve, gradually solving the problem of error catastrophe. The basic structure of the standard genetic code (8 fourfold degenerate codon boxes and 8 split codon boxes) is an example of the way information concerning the emergence of life is frozen in the biological constitution of organisms: the structure of the code contains historical information. PMID:26580656

  11. The origins of cellular life.

    PubMed

    Schrum, Jason P; Zhu, Ting F; Szostak, Jack W

    2010-09-01

    Understanding the origin of cellular life on Earth requires the discovery of plausible pathways for the transition from complex prebiotic chemistry to simple biology, defined as the emergence of chemical assemblies capable of Darwinian evolution. We have proposed that a simple primitive cell, or protocell, would consist of two key components: a protocell membrane that defines a spatially localized compartment, and an informational polymer that allows for the replication and inheritance of functional information. Recent studies of vesicles composed of fatty-acid membranes have shed considerable light on pathways for protocell growth and division, as well as means by which protocells could take up nutrients from their environment. Additional work with genetic polymers has provided insight into the potential for chemical genome replication and compatibility with membrane encapsulation. The integration of a dynamic fatty-acid compartment with robust, generalized genetic polymer replication would yield a laboratory model of a protocell with the potential for classical Darwinian biological evolution, and may help to evaluate potential pathways for the emergence of life on the early Earth. Here we discuss efforts to devise such an integrated protocell model.

  12. The origin of intermediary metabolism

    NASA Technical Reports Server (NTRS)

    Morowitz, H. J.; Kostelnik, J. D.; Yang, J.; Cody, G. D.

    2000-01-01

    The core of intermediary metabolism in autotrophs is the citric acid cycle. In a certain group of chemoautotrophs, the reductive citric acid cycle is an engine of synthesis, taking in CO(2) and synthesizing the molecules of the cycle. We have examined the chemistry of a model system of C, H, and O that starts with carbon dioxide and reductants and uses redox couples as the energy source. To inquire into the reaction networks that might emerge, we start with the largest available database of organic molecules, Beilstein on-line, and prune by a set of physical and chemical constraints applicable to the model system. From the 3.5 million entries in Beilstein we emerge with 153 molecules that contain all 11 members of the reductive citric acid cycle. A small number of selection rules generates a very constrained subset, suggesting that this is the type of reaction model that will prove useful in the study of biogenesis. The model indicates that the metabolism shown in the universal chart of pathways may be central to the origin of life, is emergent from organic chemistry, and may be unique.

  13. Nanogranular origin of concrete creep.

    PubMed

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-06-30

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium-silicate-hydrates (C-S-H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C-S-H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C-S-H forms: low density, high density, ultra-high density. We demonstrate that the creep rate ( approximately 1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years.

  14. Evolutionary origins of invasive populations

    PubMed Central

    Lee, Carol Eunmi; Gelembiuk, Gregory William

    2008-01-01

    What factors shape the evolution of invasive populations? Recent theoretical and empirical studies suggest that an evolutionary history of disturbance might be an important factor. This perspective presents hypotheses regarding the impact of disturbance on the evolution of invasive populations, based on a synthesis of the existing literature. Disturbance might select for life-history traits that are favorable for colonizing novel habitats, such as rapid population growth and persistence. Theoretical results suggest that disturbance in the form of fluctuating environments might select for organismal flexibility, or alternatively, the evolution of evolvability. Rapidly fluctuating environments might favor organismal flexibility, such as broad tolerance or plasticity. Alternatively, longer fluctuations or environmental stress might lead to the evolution of evolvability by acting on features of the mutation matrix. Once genetic variance is generated via mutations, temporally fluctuating selection across generations might promote the accumulation and maintenance of genetic variation. Deeper insights into how disturbance in native habitats affects evolutionary and physiological responses of populations would give us greater capacity to predict the populations that are most likely to tolerate or adapt to novel environments during habitat invasions. Moreover, we would gain fundamental insights into the evolutionary origins of invasive populations. PMID:25567726

  15. On the origin of Laurentia

    SciTech Connect

    Dalziel, I.W.D. . Inst. for Geophysics)

    1992-01-01

    Laurentia, the Precambrian core of the North American continent, is surrounded by late Precambrian rift systems and therefore constitutes a suspect terrane''. A geometric and geological fit can be achieved between the Atlantic margin of Laurentia and the Pacific margin of the Gondwana craton. The enigmatic Arequipa massif along the southern Peruvian coast, that yields ca. 2.0 Ga radiometric ages, is juxtaposed with the Makkovik-Ketilidian province of the same age range in Labrador and southern Greenland. The Greenville belt continues beneath the ensialic Andes of the present day to join up with the 1.3--1.0 Ga San Ignacio and Sonsas-Aguapei orogens of the Transamazonian craton. Together with the recent identification of possible continuations of the Greenville orogen in East Antarctica and of the Taconic Appalachians in southern South America, the fit supports suggestions that Laurentia originated between East Antarctica-Australia and embryonic South America prior to the opening of the Pacific Ocean basin and amalgamation of the Gondwana Cordilleran and Appalachian margins, this implies that there may have been two supercontinents during the Neoproterozoic, before and after opening of the Pacific Ocean. As Laurentia and Gondwana appear to have collided on at least two occasions during the Paleozoic, this scenario therefore calls to question the existence of so-called supercontinental cycles. The Arica bight of the present day may reflect a primary reentrant in the South American continental margin that controlled subduction processes along the Andean margin and eventually led to uplift of the Altiplano.

  16. On the Origin of Interoception

    PubMed Central

    Ceunen, Erik; Vlaeyen, Johan W. S.; Van Diest, Ilse

    2016-01-01

    Over the course of a century, the meaning of interoception has changed from the restrictive to the inclusive. In its inclusive sense, it bears relevance to every individual via its link to emotion, decision making, time-perception, health, pain, and various other areas of life. While the label for the perception of the body state changes over time, the need for an overarching concept remains. Many aspects can make any particular interoceptive sensation unique and distinct from any other interoceptive sensation. This can range from the sense of agency, to the physical cause of a sensation, the ontogenetic origin, the efferent innervation, and afferent pathways of the tissue involved amongst others. In its overarching meaning, interoception primarily is a product of the central nervous system, a construct based on an integration of various sources, not per se including afferent information. This paper proposes a definition of interoception as based on subjective experience, and pleas for the use of specific vocabulary in addressing the many aspects that contribute to it. PMID:27242642

  17. ORIGINS AND RAMIFICATIONS OF PHARMACEUTICALS ...

    EPA Pesticide Factsheets

    Perhaps more so than with any other class of pollutants, the occurrence of pharmaceuticals and personal care products (PPCPS) in the environment highlights the immediate, intimate, and inseparable connection between the personal activities of individual citizens and their environment. PPCPS, in contrast to other types of pollutants, owe their origins in the environment directly to their worldwide, universal, frequent, highly dispersed, and individually small but cumulative usage by multitudes of individuals - as opposed to the larger, highly delineated, and more controllable industrial manufacturing/usage of most high- volume synthetic chemicals. Many PPCPs (as well as their metabolites and transformation products) can enter the environment following ingestion or application by the user or administration to domestic animals. Disposal of unused/expired PPCPs in landfills and in domestic sewage is another route to the environment. The aquatic environment serves as the major, ultimate receptacle for these chemicals, for which little is known with respect to actual or potential adverse effects. Domestic sewage treatment plants are not designed to remove PPCPS, and the efficiencies with which they are removed vary from nearly complete to ineffective. While PPCPs in the environment (or domestic drinking water) are not regulated, and even though their concentrations are extremely low (ng/L-@Lg/L), the consequences of exposure to multiple compounds having different as w

  18. The origin of intermediary metabolism

    PubMed Central

    Morowitz, Harold J.; Kostelnik, Jennifer D.; Yang, Jeremy; Cody, George D.

    2000-01-01

    The core of intermediary metabolism in autotrophs is the citric acid cycle. In a certain group of chemoautotrophs, the reductive citric acid cycle is an engine of synthesis, taking in CO2 and synthesizing the molecules of the cycle. We have examined the chemistry of a model system of C, H, and O that starts with carbon dioxide and reductants and uses redox couples as the energy source. To inquire into the reaction networks that might emerge, we start with the largest available database of organic molecules, Beilstein on-line, and prune by a set of physical and chemical constraints applicable to the model system. From the 3.5 million entries in Beilstein we emerge with 153 molecules that contain all 11 members of the reductive citric acid cycle. A small number of selection rules generates a very constrained subset, suggesting that this is the type of reaction model that will prove useful in the study of biogenesis. The model indicates that the metabolism shown in the universal chart of pathways may be central to the origin of life, is emergent from organic chemistry, and may be unique. PMID:10859347

  19. Origin of giant Martian polygons

    NASA Technical Reports Server (NTRS)

    Mcgill, George E.; Hills, L. S.

    1992-01-01

    Extensive areas of the Martian northern plains in Utopia and Acidalia planitiae are characterized by 'polygonal terrane'. Polygonal terrane consists of material cut by complex troughs defining a pattern resembling mudcracks, columnar joints, or frost-wedge polygons on earth. However, the Martian polygons are orders of magnitude larger than these potential earth analogues, leading to severe mechanical difficulties for genetic models based on simple analogy arguments. Plate-bending and finite element models indicate that shrinkage of desiccating sediment or cooling volcanics accompanied by differential compaction over buried topography can account for the stresses responsible for polygon troughs as well as the large size of the polygons. Although trough widths and depths relate primarily to shrinkage, the large scale of the polygonl pattern relates to the spacing between topographic elevations on the surface buried beneath polygonal terrane material. Geological relationships favor a sedimentary origin for polygonal terrane material, but our model is not dependent on the specific genesis. Our analysis also suggests that the polygons must have formed at a geologically rapid rate.

  20. Origin and properties of GEMS

    SciTech Connect

    Dai, Z R; Bradley, J P

    2006-04-11

    GEMS are to the outer solar system what chondrules are to the inner solar system. Ten years after it was first proposed that GEMS are the long-sought interstellar amorphous silicates, ion microprobe measurements have confirmed that some of them are indeed interstellar amorphous silicates. The new challenges are to obtain even higher precision isotope measurements from these submicrometer-sized objects and to clarify how and where they originally formed. Individual GEMS exhibit a strikingly narrow (0.1-0.5 {micro}m diameter) size distribution and they are systematically depleted from solar abundances in S/Si, Mg/Si, Ca/Si and Fe/Si, implying that they formed by a common mechanism. Mineralogical and petrographic evidence suggest that irradiation processing may be that mechanism. Recent nanometer-scale compositional mapping using new-generation transmission electron microscopes reveals that truly pristine GEMS may be relatively rare and new metrics need to be developed to distinguish the primordial properties of GEMS from more recent secondary alteration effects.

  1. Nanogranular origin of concrete creep

    PubMed Central

    Vandamme, Matthieu; Ulm, Franz-Josef

    2009-01-01

    Concrete, the solid that forms at room temperature from mixing Portland cement with water, sand, and aggregates, suffers from time-dependent deformation under load. This creep occurs at a rate that deteriorates the durability and truncates the lifespan of concrete structures. However, despite decades of research, the origin of concrete creep remains unknown. Here, we measure the in situ creep behavior of calcium–silicate–hydrates (C–S–H), the nano-meter sized particles that form the fundamental building block of Portland cement concrete. We show that C–S–H exhibits a logarithmic creep that depends only on the packing of 3 structurally distinct but compositionally similar C–S–H forms: low density, high density, ultra-high density. We demonstrate that the creep rate (≈1/t) is likely due to the rearrangement of nanoscale particles around limit packing densities following the free-volume dynamics theory of granular physics. These findings could lead to a new basis for nanoengineering concrete materials and structures with minimal creep rates monitored by packing density distributions of nanoscale particles, and predicted by nanoscale creep measurements in some minute time, which are as exact as macroscopic creep tests carried out over years. PMID:19541652

  2. A Link between ORC-Origin Binding Mechanisms and Origin Activation Time Revealed in Budding Yeast

    PubMed Central

    Hoggard, Timothy; Shor, Erika; Müller, Carolin A.; Nieduszynski, Conrad A.; Fox, Catherine A.

    2013-01-01

    Eukaryotic DNA replication origins are selected in G1-phase when the origin recognition complex (ORC) binds chromosomal positions and triggers molecular events culminating in the initiation of DNA replication (a.k.a. origin firing) during S-phase. Each chromosome uses multiple origins for its duplication, and each origin fires at a characteristic time during S-phase, creating a cell-type specific genome replication pattern relevant to differentiation and genome stability. It is unclear whether ORC-origin interactions are relevant to origin activation time. We applied a novel genome-wide strategy to classify origins in the model eukaryote Saccharomyces cerevisiae based on the types of molecular interactions used for ORC-origin binding. Specifically, origins were classified as DNA-dependent when the strength of ORC-origin binding in vivo could be explained by the affinity of ORC for origin DNA in vitro, and, conversely, as ‘chromatin-dependent’ when the ORC-DNA interaction in vitro was insufficient to explain the strength of ORC-origin binding in vivo. These two origin classes differed in terms of nucleosome architecture and dependence on origin-flanking sequences in plasmid replication assays, consistent with local features of chromatin promoting ORC binding at ‘chromatin-dependent’ origins. Finally, the ‘chromatin-dependent’ class was enriched for origins that fire early in S-phase, while the DNA-dependent class was enriched for later firing origins. Conversely, the latest firing origins showed a positive association with the ORC-origin DNA paradigm for normal levels of ORC binding, whereas the earliest firing origins did not. These data reveal a novel association between ORC-origin binding mechanisms and the regulation of origin activation time. PMID:24068963

  3. Cosmic Origin and Theology of the Revelation

    NASA Astrophysics Data System (ADS)

    Guijarro, José Francisco

    2007-04-01

    All along cultural history man has asked himself about the origin of man, the origin of life ante the origin of the cosmos. Regarding the question about the origin of the cosmos, any theological research must settle before any other goal the question of its language: what we understand as scientific, mythical or theological language. The biblical texts on Creation are analyzed in their historical, cultural and theological context. It is concluded that the fundamental religious meanings of the biblical texts are not in opposition to scientific interpretation of cosmic origin.

  4. Fever of unknown origin: a clinical approach.

    PubMed

    Cunha, Burke A; Lortholary, Olivier; Cunha, Cheston B

    2015-10-01

    Fevers of unknown origin remain one of the most difficult diagnostic challenges in medicine. Because fever of unknown origin may be caused by over 200 malignant/neoplastic, infectious, rheumatic/inflammatory, and miscellaneous disorders, clinicians often order non-clue-based imaging and specific testing early in the fever of unknown origin work-up, which may be inefficient/misleading. Unlike most other fever-of-unknown-origin reviews, this article presents a clinical approach. Characteristic history and physical examination findings together with key nonspecific test abnormalities are the basis for a focused clue-directed fever of unknown origin work-up.

  5. [The origin of informed consent].

    PubMed

    Mallardi, V

    2005-10-01

    The principle of informed consent, aimed at the lawfulness of health assistance, tends to reflect the concept of autonomy and of decisional autodetermination of the person requiring and requesting medical and/or surgical interventions. This legal formula, over the last few years, has gained not only considerable space but also importance in the doctrinal elaboration and approaches, as well as juridical interpretations, thereby influencing the everyday activities of the medical profession. Informed consent is still the object of continuous explorations, not only asfar as concerns the already confirmed theoretical profile but, instead, the ambiguous practical and consequential aspect. Analysing how the concept and role of consensus was born and developed with the more adequate and reasonable excursions to make it valid and obtain it, it is impossible not to take into consideration, on the one hand, the very ancient philosophical origins and, on the other, the fact that it was conditioned by religion with the moral aspects and the accelerated deontological evolution with pathways parallel to the needs and the progress offered by new forms of treatment and novel biotechnological applications. The principle of consent is a relatively new condition. In fact, already in the times of not only the Egyptian civilisation, but also the Greek and Roman, documents have been found which show how the doctor's intervention had, in some way, first to be approved by the patient. Plato (law IV) had already foreseen the problems, the procedures and the modes of information which are, in synthesis, at the root of the principles of the present formula of informed consent and correlated the practice of the information and consensus with the quality and social position of the patient. The only guarantee that the patient might have, derived from a fundamental principle of medicine of all times: "in disease, focus on two aims, to improve and not to cause damage". A figure can be recognised

  6. Philopatry: A return to origins

    USGS Publications Warehouse

    Pearce, John M.

    2007-01-01

    The potential danger of applying philopatry to non-natal and nonbreeding conditions is that it creates the expectation of certain outcomes, such as low dispersal rates, population genetic differentiation, and unique population segments, when such conditions may not exist. Given that most avian species do not molt, winter, or have migratory stopovers where they breed, I propose that the term “philopatry” and its genetic expectations be used only in relation to natal philopatry and not extended to (1) breeding- site fidelity of individuals whose natal areas are unknown and (2) nonbreeding areas where site- faithful behavior is observed. I believe this correctly distinguishes natal philopatry as a specific type of site fidelity with its own implications for population genetics and dynamics. Thus, philopatry should be viewed as synonymous and interchangeable with the terms “natal-site fidelity” and “natal philopatry,” and the term “breeding-site fidelity” should replace “breeding philopatry,” because it reflects the unknown natal origins of birds captured as adults. Although the broader condition of site fidelity may have implications for fitness, mate pairing, and population delineation—as examined in several studies (Robertson and Cooke 1999, Merom et al. 2000, Iverson et al. 2004, Mehl et al. 2004)—future investigations of site fidelity should be pursued without automatically invoking the term “philopatry” and assuming that the genetic and demographic connotations of natal philopatry also apply. In contrast to philopatry, the probability of fidelity (F) and dispersal (1 − F) are estimable parameters (Burnham 1993, Kendall and Nichols 2004), and the demographic and genetic consequences of site fidelity, regardless of where it occurs, can serve as hypotheses for testing with multiple data types (e.g., Arsenault et al. 2005). Such data mergers should enhance our understanding of the demographic, behavioral, and genetic implications

  7. Origin of Small Tectonic Plates

    NASA Astrophysics Data System (ADS)

    Mallard, C.; Coltice, N.; Seton, M.; Müller, D.; Tackley, P.

    2015-12-01

    The plate tectonic theory allowed to split the Earth surface into 6 (Le Pichon 1968) to 52 tectonic plates (Bird 2003). These plates are separated into two groups: the first of 7 large plates and the second of numerous smaller plates (Morra et al 2013). Previous studies using the reconstruction of the past 200 My, suggest that the size of large plates is driven by mantle flow. But the tools employed are descriptive (Morra et al 2013, Sornette and Pisarenko 2003), hence ignoring forces and physical principles within the lithosphere and the mantle. The processes at the origin of small plates remain unknown. We developed a new approach to explain the plate sizes. We demonstrate that the physics of convection drives it. We applied plate tectonics theory on 3D spherical convection models generating plate-like motions, which give access to a complete survey of data: velocities, viscosity and heat flow. Our data show that (1) the large plates depend on the dominating scale of the convective flow due to the initiation or the shutdown of subductions; (2) the smaller plates are generated thanks to large variability of regional stresses along subduction zone by slab pull and suction influenced by the geometry of trenches. Our results are consistent with the quick reorganizations of back-arc basins occuring synchronously with the modification of subduction zones geometry around the Pacific plate (Sdrolias et al 2004). Hence, we conclude that (1) the decreasing number of small plates in the plate reconstructions back in time is an artifact induced by their short lifetime, that is why they are artificially ignored; (2) the geometry of past trenches is simplified leading to an underestimation of the length of subduction zones.

  8. Structural Origins of Silk Piezoelectricity

    PubMed Central

    Yucel, Tuna; Cebe, Peggy

    2012-01-01

    Uniaxially oriented, piezoelectric silk films were prepared by a two-step method that involved: (1) air drying aqueous, regenerated silk fibroin solutions into films, and (2) drawing the silk films to a desired draw ratio. The utility of two different drawing techniques, zone drawing and water immersion drawing were investigated for processing the silk for piezoelectric studies. Silk films zone drawn to a ratio of λ= 2.7 displayed relatively high dynamic shear piezoelectric coefficients of d14 = −1.5 pC/N, corresponding to over two orders of magnitude increase in d14 due to film drawing. A strong correlation was observed between the increase in the silk II, β-sheet content with increasing draw ratio measured by FTIR spectroscopy (Cβ∝ e2.5 λ), the concomitant increasing degree of orientation of β-sheet crystals detected via WAXD (FWHM = 0.22° for λ= 2.7), and the improvement in silk piezoelectricity (d14∝ e2.4 λ). Water immersion drawing led to a predominantly silk I structure with a low degree of orientation (FWHM = 75°) and a much weaker piezoelectric response compared to zone drawing. Similarly, increasing the β-sheet crystallinity without inducing crystal alignment, e.g. by methanol treatment, did not result in a significant enhancement of silk piezoelectricity. Overall, a combination of a high degree of silk II, β-sheet crystallinity and crystalline orientation are prerequisites for a strong piezoelectric effect in silk. Further understanding of the structural origins of silk piezoelectricity will provide important options for future biotechnological and biomedical applications of this protein. PMID:23335872

  9. The Doctorate as an Original Contribution to Knowledge: Considering Relationships between Originality, Creativity, and Innovation

    ERIC Educational Resources Information Center

    Baptista, Ana; Frick, Liezel; Holley, Karri; Remmik, Marvi; Tesch, Jakob; Âkerlind, Gerlese

    2015-01-01

    This article explores the meaning of originality in doctoral studies and its relationship with creativity and innovation. Doctoral theses are expected to provide an original contribution to knowledge in their field all over the world. However, originality is not well defined. Using the literature on concepts of originality as a foundation, this…

  10. The origin of phage virology.

    PubMed

    Pennazio, Sergio

    2006-01-01

    The history of bacteriophage (phage) had its start in 1915, when Twort isolated an unusual filterable and infectious agent from excrete of patients struck by diarrhoea; this discovery was followed by an analogous, and probably independent, finding of d'Hérelle in 1917. For several years phage research made scant progress but great attention was paid to the question of phage nature, which saw the contrast between d'Hérelle and Bordet's views (living against chemical nature, respectively). This situation changed with the independent discovery of lysogeny, in 1925, thanks to Bordet and Bail: this phenomenon was considered of genetical origin, a view that Wollman interpreted by assimilating the properties of phage to those of gene (according to a previous idea of Muller). In the 1930s, Burnet's work opened a new era by demonstrating the occurrence of several species of phages and their antigenic property. In the same period, the physical and chemical characteristics of these viruses were disclosed thanks, in particular, to the work of Schlesinger, who first demonstrated that a virus (phage) was constituted of nucleoproteins. The peculiarity of phage was finally shown after the invention of electron microscope: H. Ruska, in 1940, and Anderson and Luria in the next years, obtained the first images of tailed phages, a finding that strongly helped the investigation on the first steps of the infection process. The decisive impulse to phage virology came from Delbrück, a physicist who entered biology giving it a new arrangement. The so-called "phage group" assembled brilliant minds (Luria, Hershey and Delbrück himself, and later a dozen of other scientists): this group faced three fundamental questions of phage virology, i.e., the mechanisms of attack, multiplication and lysis. In ten years' time, phage virology became an integrant part of molecular biology, also thanks to the discovery of the genetical properties of DNA: in such scientific context, Delbrück, Luria and

  11. Modern human origins: progress and prospects.

    PubMed Central

    Stringer, Chris

    2002-01-01

    The question of the mode of origin of modern humans (Homo sapiens) has dominated palaeoanthropological debate over the last decade. This review discusses the main models proposed to explain modern human origins, and examines relevant fossil evidence from Eurasia, Africa and Australasia. Archaeological and genetic data are also discussed, as well as problems with the concept of 'modernity' itself. It is concluded that a recent African origin can be supported for H. sapiens, morphologically, behaviourally and genetically, but that more evidence will be needed, both from Africa and elsewhere, before an absolute African origin for our species and its behavioural characteristics can be established and explained. PMID:12028792

  12. A winding road to origin discovery

    PubMed Central

    Mesner, Larry D.; Dijkwel, Pieter A.

    2010-01-01

    Studies in our laboratory over the last three decades have shown that the Chinese hamster dihydrofolate reductase (DHFR) origin of replication corresponds to a broad zone of inefficient initiation sites distributed throughout the spacer between the convergently transcribed DHFR and 2BE2121 genes. It is clear from mutational analysis that none of these sites is genetically required for controlling origin activity. However, the integrity of the promoter of the DHFR gene is needed to activate the downstream origin, while the 3′ processing signals prevent invasion and inactivation of the downstream origin by transcription forks. Several other origins in metazoans have been shown to correspond to zones of inefficient sites, while a different subset appears to be similar to the fixed replicators that characterize origins in S. cerevisiae and lower organisms. These observations have led us to suggest a model in which the mammalian genome is dotted with a hierarchy of degenerate, redundant, and inefficient replicators at intervals of a kilobase or less, some of which may have evolved to be highly circumscribed and efficient. The activities of initiation sites are proposed to be largely regulated by local transcription and chromatin architecture. Recently, we and others have devised strategies for identifying active origins on a genome-wide scale in order to define their distributions between fixed and dispersive origin types and to detect relationships among origins, genes, and epigenetic markers. The global pictures emerging are suggestive but far from complete and appear to be plagued by some of the same uncertainties that have led to conflicting views of individual origins in the past (particularly DHFR). In this paper, we will trace the history of origin discovery in mammalian genomes, primarily using the well-studied DHFR origin as a model, because it has been analyzed by nearly every available origin mapping technique in several different laboratories, while many

  13. A winding road to origin discovery.

    PubMed

    Hamlin, Joyce L; Mesner, Larry D; Dijkwel, Pieter A

    2010-01-01

    Studies in our laboratory over the last three decades have shown that the Chinese hamster dihydrofolate reductase (DHFR) origin of replication corresponds to a broad zone of inefficient initiation sites distributed throughout the spacer between the convergently transcribed DHFR and 2BE2121 genes. It is clear from mutational analysis that none of these sites is genetically required for controlling origin activity. However, the integrity of the promoter of the DHFR gene is needed to activate the downstream origin, while the 3' processing signals prevent invasion and inactivation of the downstream origin by transcription forks. Several other origins in metazoans have been shown to correspond to zones of inefficient sites, while a different subset appears to be similar to the fixed replicators that characterize origins in S. cerevisiae and lower organisms. These observations have led us to suggest a model in which the mammalian genome is dotted with a hierarchy of degenerate, redundant, and inefficient replicators at intervals of a kilobase or less, some of which may have evolved to be highly circumscribed and efficient. The activities of initiation sites are proposed to be largely regulated by local transcription and chromatin architecture. Recently, we and others have devised strategies for identifying active origins on a genome-wide scale in order to define their distributions between fixed and dispersive origin types and to detect relationships among origins, genes, and epigenetic markers. The global pictures emerging are suggestive but far from complete and appear to be plagued by some of the same uncertainties that have led to conflicting views of individual origins in the past (particularly DHFR). In this paper, we will trace the history of origin discovery in mammalian genomes, primarily using the well-studied DHFR origin as a model, because it has been analyzed by nearly every available origin mapping technique in several different laboratories, while many

  14. Optimal Placement of Origins for DNA Replication

    NASA Astrophysics Data System (ADS)

    Karschau, Jens; Blow, J. Julian; de Moura, Alessandro P. S.

    2012-02-01

    DNA replication is an essential process in biology and its timing must be robust so that cells can divide properly. Random fluctuations in the formation of replication starting points, called origins, and the subsequent activation of proteins lead to variations in the replication time. We analyze these stochastic properties of DNA and derive the positions of origins corresponding to the minimum replication time. We show that under some conditions the minimization of replication time leads to the grouping of origins, and relate this to experimental data in a number of species showing origin grouping.

  15. Employment Hardship among Mexican-Origin Women

    ERIC Educational Resources Information Center

    De Anda, Roberto M.

    2005-01-01

    This study compares the prevalence and causes of employment hardship between Mexican-origin and White women. Data come from the March 1992, 1996, and 2000 Current Population Surveys. Using logistic regression, the author assesses whether there is a difference between Mexican-origin and White women in employment hardship, controlling for personal…

  16. Starkweather Originality Test for Young Children.

    ERIC Educational Resources Information Center

    Starkweather, Elizabeth K.

    The Starkweather Originality Test is designed to measure the creative potential of children ranging in age from 3 years, 6 months to 6 years, 6 months. Children younger than 3 years, 6 months can be given the Originality Test if their ability to communicate verbally is satisfactorily demonstrated during the pretest. The test is individually…

  17. The Gestural Theory of Language Origins

    ERIC Educational Resources Information Center

    Armstrong, David F.

    2008-01-01

    The idea that iconic visible gesture had something to do with the origin of language, particularly speech, is a frequent element in speculation about this phenomenon and appears early in its history. Socrates hypothesizes about the origins of Greek words in Plato's satirical dialogue, "Cratylus", and his speculation includes a possible…

  18. 5 CFR 1201.2 - Original jurisdiction.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Original jurisdiction. 1201.2 Section 1201.2 Administrative Personnel MERIT SYSTEMS PROTECTION BOARD ORGANIZATION AND PROCEDURES PRACTICES AND PROCEDURES Jurisdiction and Definitions § 1201.2 Original jurisdiction. The Board's...

  19. Prostate cancer in men of African origin.

    PubMed

    McGinley, Kathleen F; Tay, Kae Jack; Moul, Judd W

    2016-02-01

    Men of African origin are disproportionately affected by prostate cancer: prostate cancer incidence is highest among men of African origin in the USA, prostate cancer mortality is highest among men of African origin in the Caribbean, and tumour stage and grade at diagnosis are highest among men in sub-Saharan Africa. Socioeconomic, educational, cultural, and genetic factors, as well as variations in care delivery and treatment selection, contribute to this cancer disparity. Emerging data on single-nucleotide-polymorphism patterns, epigenetic changes, and variations in fusion-gene products among men of African origin add to the understanding of genetic differences underlying this disease. On the diagnosis of prostate cancer, when all treatment options are available, men of African origin are more likely to choose radiation therapy or to receive no definitive treatment than white men. Among men of African origin undergoing surgery, increased rates of biochemical recurrence have been identified. Understanding differences in the cancer-survivorship experience and quality-of-life outcomes among men of African origin are critical to appropriately counsel patients and improve cultural sensitivity. Efforts to curtail prostate cancer screening will likely affect men of African origin disproportionately and widen the racial disparity of disease.

  20. 7 CFR 201.58b - Origin.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Origin. 201.58b Section 201.58b Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... REGULATIONS Examinations in the Administration of the Act § 201.58b Origin. The presence of incidental...

  1. The origin of turtles: a paleontological perspective.

    PubMed

    Joyce, Walter G

    2015-05-01

    The origin of turtles and their unusual body plan has fascinated scientists for the last two centuries. Over the course of the last decades, a broad sample of molecular analyses have favored a sister group relationship of turtles with archosaurs, but recent studies reveal that this signal may be the result of systematic biases affecting molecular approaches, in particular sampling, non-randomly distributed rate heterogeneity among taxa, and the use of concatenated data sets. Morphological studies, by contrast, disfavor archosaurian relationships for turtles, but the proposed alternative topologies are poorly supported as well. The recently revived paleontological hypothesis that the Middle Permian Eunotosaurus africanus is an intermediate stem turtle is now robustly supported by numerous characters that were previously thought to be unique to turtles and that are now shown to have originated over the course of tens of millions of years unrelated to the origin of the turtle shell. Although E. africanus does not solve the placement of turtles within Amniota, it successfully extends the stem lineage of turtles to the Permian and helps resolve some questions associated with the origin of turtles, in particular the non-composite origin of the shell, the slow origin of the shell, and the terrestrial setting for the origin of turtles.

  2. The RNA World and its origins

    NASA Technical Reports Server (NTRS)

    Schwartz, A. W.

    1995-01-01

    The theory of the "RNA World" states that the first molecular systems to display the properties of self-replication and evolution were RNA molecules. The origin of life not only depended crucially upon this event, but RNA molecules can even be viewed as the first "living" things. In recent years this theory has gained ascendancy over competing ideas and is now largely accepted by biologists as the most satisfactory explanation for the origin of life. The reasons for this development will be reviewed and the problem of the origin of the first RNA molecules will be discussed.

  3. Ultrahigh Energy Cosmic Rays: A Galactic Origin?

    NASA Astrophysics Data System (ADS)

    Eichler, David; Globus, Noemie; Kumar, Rahul; Gavish, Eyal

    2016-04-01

    It is suggested that essentially all UHECRs we detect, including those at the highest energies, originate in our Galaxy. It is shown that even if the density of sources decreases with Galactic radius, then the anisotropy and composition can be understood. Inward anisotropy, as recently reported by the Auger collaboration can be understood as drift along the current sheet of UHECRs, originating outside of the solar circle, as predicted in Kumar & Eichler, while those originating within the solar circle exit the Galaxy at high latitudes.

  4. 19 CFR 10.594 - Originating goods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... entirely in the territory of one or more of the Parties and: (1) Each non-originating material used in the production of the good undergoes an applicable change in tariff classification specified in General Note...

  5. 19 CFR 10.531 - Originating goods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the Parties; (b) The good is transformed in one or both of the Parties so that: (1) Each non-originating material undergoes an applicable change in tariff classification specified in General Note...

  6. Blue Origin Conducts Pad Escape Test

    NASA Video Gallery

    Blue Origin conducted a successful pad escape test Oct. 19 at the company's West Texas launch site, firing its pusher escape motor and launching a full-scale suborbital crew capsule from a simulate...

  7. The Solar System and Its Origin

    ERIC Educational Resources Information Center

    Dormand, J. R.

    1973-01-01

    Presents a brief explanation of the solar system, including planets, asteroids, satellites, comets, planetary orbits, as well as, old and recent cosmogonic theories. Indicates that man is nearer a solution to the origin of the planetary system than ever before.

  8. Origins of life: a route to nanotechnology.

    PubMed

    Sowerby, S J; Holm, N G; Petersen, G B

    2001-06-01

    The origins of life and nanotechnology are two seemingly disparate areas of scientific investigation. However, the fundamental questions of life's beginnings and the applied construction of a Drexlerian nanotechnology both share a similar problem; how did and how can self-reproducing molecular machines originate? Here we draw attention to the coincidence between nanotechnology and origins research with particular attention paid to the spontaneous adsorption and scanning tunneling microscopy investigation of purine and pyrimidine bases self-organized into monolayers, adsorbed to the surfaces of crystalline solids. These molecules which encode biological information in nucleic acids, can form supramolecular architectures exhibiting enantiomorphism with the complexity to store and encode putative protobiological information. We conclude that the application of nanotechnology to the investigation of life's origins, and vice versa, could provide a viable route to an evolution-driven synthetic life.

  9. Origin and evolution of ordinary chondrite meteorites

    NASA Technical Reports Server (NTRS)

    Scott, E. R. D.; Taylor, G. J.; Keil, K.

    1985-01-01

    The effects of heating on the chemical composition, minerology, and texture of chondrite meteorites are discussed chondrite origin and evolution. Various asteroidal and nebular heating mechanisms are considered to account meteorite compositions.

  10. Geochemistry and the origin of life

    NASA Technical Reports Server (NTRS)

    Kvenvolden, K. A.

    1974-01-01

    The origin of life on earth is examined from a viewpoint stressing the validity of the concept of chemical evolution. The different geological formations supporting the mechanisms of the theory are described; the stage of chemical evolution (preceding that of biological evolution) would have taken place from the time of the origin of the earth and meteorites, 4.6 billion years ago, to the early Precambrian period, about 3.2 billion years ago. Specific aspects of the problem discussed include amino acids from spark discharges and their comparison with the Murchison meteorite amino acids, the properties and theory of genesis of the carbonaceous complex within the cold Bokevelt meteorite, ammonion ion concentration in the primitive ocean, the oxygen isotope chemistry of ancient charts, the origin and rise of oxygen concentration in the earth's atmosphere, Precambrian microorganisms and evolutionary events prior to the origin of vascular plants, and biogenicity and significance of the oldest known stromatolites.

  11. 46 CFR 503.54 - Original classification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... FEDERAL MARITIME COMMISSION GENERAL AND ADMINISTRATIVE PROVISIONS PUBLIC INFORMATION Information Security... subject matter, or to the Information Security Oversight Office, for review and a classification... originally classify information. (b) If a Commission Member or employee develops information that appears...

  12. 46 CFR 503.54 - Original classification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... FEDERAL MARITIME COMMISSION GENERAL AND ADMINISTRATIVE PROVISIONS PUBLIC INFORMATION Information Security... subject matter, or to the Information Security Oversight Office, for review and a classification... originally classify information. (b) If a Commission Member or employee develops information that appears...

  13. 46 CFR 503.54 - Original classification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... FEDERAL MARITIME COMMISSION GENERAL AND ADMINISTRATIVE PROVISIONS PUBLIC INFORMATION Information Security... subject matter, or to the Information Security Oversight Office, for review and a classification... originally classify information. (b) If a Commission Member or employee develops information that appears...

  14. 46 CFR 503.54 - Original classification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... FEDERAL MARITIME COMMISSION GENERAL AND ADMINISTRATIVE PROVISIONS PUBLIC INFORMATION Information Security... subject matter, or to the Information Security Oversight Office, for review and a classification... originally classify information. (b) If a Commission Member or employee develops information that appears...

  15. Blue Origin Tests BE-3 Engine

    NASA Video Gallery

    Blue Origin successfully fires the thrust chamber assembly for its new 100,000 pound thrust BE-3 liquid oxygen, liquid hydrogen rocket engine. As part of the company's Reusable Booster System (RBS)...

  16. An Introduction to Comets and Their Origin.

    ERIC Educational Resources Information Center

    Chapman, Robert D.; Brandt, John C.

    1985-01-01

    Presents excerpts from "The Comet Book," a nontechnical primer on comets. Various topics discusses in these excerpts include such basic information about comets as their components, paths, and origins. (DH)

  17. The Origin of Life in Comets

    NASA Astrophysics Data System (ADS)

    Napier, W. M.; Wickramasinghe, J. T.; Wickramasinghe, N. C.

    Mechanisms of interstellar panspermia have recently been identified whereby life, wherever it has originated, will disperse throughout the habitable zone of the Galaxy within a few billion years. This re-opens the question of where life originated. The interiors of comets, during their aqueous phase, seem to provide environments no less favourable for the origin of life than that of the early Earth. Their combined mass throughout the Galaxy overwhelms that of suitable terrestrial environments by about 20 powers of ten, while the lifetimes of friendly prebiotic environments within them exceeds that of localised terrestrial regions by another four or five powers of ten. We propose that the totality of comets around G-dwarf Sun-like stars offers an incomparably more probable setting for the origin of life than any that was available on the early Earth.

  18. Determination of Origin of NASA Stratospheric Particles

    NASA Astrophysics Data System (ADS)

    Kapišinský, I.; Figusch, V.; Hajduk, A.; Ivan, J.; Iždinský, K.

    1996-04-01

    Paper presents a reanalysis of four stratospheric particles registered in the Cosmic Dust Catalogs (CDC). Two particles have been classifed in the NASA Johnson Space Centre (JSC) in Houston as natural, terrestrial contaminants and the origin of the other two particles was found questionable, probably cosmic. Present study has confirmed these conclusions; however some new additional features in the chemical analysis have been found which can finally determine the classification of the particles with unclear origin.

  19. Luna 24 origins - Some trace element constraints

    NASA Technical Reports Server (NTRS)

    Jovanovic, S.; Jensen, K. J.; Reed, G. W., Jr.

    1978-01-01

    Luna 24 basaltic material originated in the particular volume of the lunar crust that produced Apollo 11 and Luna 16 basaltic material; it has the same Clr/P2O5 (r = residual) signature. Ru-Os contents (Barsukov et al., 1977) and a number of radiogenic age measurements place Luna 24 basalt origins stratigraphically in a layer between those from which Apollo 15 and Apollo 11 and 17 basalts were derived.

  20. Recurring Slope Lineae on Mars: Atmospheric Origin?

    NASA Astrophysics Data System (ADS)

    McEwen, AS; Chojnacki, M.; Dundas, C.; Ojha, L.; Masse, M.; Schaefer, E.; Leung, C.

    2015-10-01

    Recurring Slope Lineae (RSL) are seasonal flows or seeps on warm Martian slopes. Observed gradual or incremental growth, fading, and yearly recurrence can be explained by seasonal seeps of water, which is probably salty. The origin of the water is not understood, but several observations indicate a key role for atmospheric processes. If sufficient deliquescent salts are present at these locations, the water could be entirely of atmospheric origin.

  1. Origins, Evolution, and Fate of Brown Dwarfs

    NASA Technical Reports Server (NTRS)

    Martin, Eduardo

    2003-01-01

    Research related to the origins, evolution and fate of brown dwarfs is presented. The topics include: 1) Imaging surveys for brown dwarfs; 2) Companion detection techniques; 3) Measurements of fundamental properties of brown dwarfs; 4) Classification schemes for ultracool dwarfs; 5) Origins and evolution of brown dwarfs; 6) Ultracool atmospheres and interiors; 7) Time variable phenomena in brown dwarfs; 8) Comparisons between brown dwarfs and planets; 9) Substellar mass functions; and 10) Future facilities.

  2. Shock Waves and the Origin of Life

    DTIC Science & Technology

    1977-01-01

    The thunder shock-wave can be approximated by the so-called cyl- indrical ’blast wave theory ’ (22, 24) for a single lightning stroke. The ’ theory ’ is... theory can be finally tested. Historically, the question of how life originated received the answer which was contemporarily available within the...Origin of Species," that the theory of spontaneous gpneration was finally aisproved by Louis Pasteur. In a series of exceptiorally lucid experiments

  3. Origin of Fibrosing Cells in Systemic Sclerosis

    PubMed Central

    Ebmeier, Sarah; Horsley, Valerie

    2015-01-01

    Purpose of review Systemic sclerosis (SSc), an autoimmune disease of unknown origin, is characterized by progressive fibrosis that can affect all organs of the body. To date, there are no effective therapies for the disease. This paucity of treatment options is primarily due to limited understanding of the processes that initiate and promote fibrosis in general and a lack of animal models that specifically emulate the chronic nature of systemic sclerosis. Most models capitulate acute injury-induced fibrosis in specific organs. Regardless of the model however, a major outstanding question in the field is the cellular origin of fibrosing cells. Recent findings A multitude of origins have been proposed in a variety of tissues, including resident tissue stroma, fibrocytes, pericytes, adipocytes, epithelial cells, and endothelial cells. Developmentally derived fibroblast lineages have recently been elucidated with fibrosing potential in injury models. Increasing data supports the pericyte as a fibrosing cell origin in diverse fibrosis models and adipocytes have recently been proposed. Fibrocytes, epithelial cells, and endothelial cells have been examined, though data does not as strongly support these possible origins. Summary In this review, we discuss recent evidence arguing in favor of and against proposed origins of fibrosing cells in diverse models of fibrosis. We highlight outstanding controversies and propose how future research may elucidate how fibrosing cells arise and what processes can be targeted in order to treat systemic sclerosis. PMID:26352735

  4. Metastatic adenocarcinoma of unknown primary origin.

    PubMed

    Hammar, S P

    1998-12-01

    Adenocarcinomas account for up to 60% of all metastatic neoplasms of unknown primary origin. In general, adenocarcinomas are the most difficult metastatic tumor to accurately identify the primary site. Some metastatic adenocarcinomas have distinctive histological features that allow for their site determination (eg, colonic adenocarcinoma, bronchioloalveolar cell carcinoma), although the majority of metastatic adenocarcinomas have histological features that are not distinctive enough to allow for a specific diagnosis of their origin. For this reason, electron microscopy and immunohistochemistry have been used to help identify the exact type (origin) of metastatic adenocarcinomas. Relatively specific ultrastructural features used to diagnose metastatic adenocarcinomas of unknown primary origin include tubular myelin, intranuclear surfactant apoprotein tubular inclusions, Clara cell granules, uniform short microvilli with filamentous cores and core rootlets, Langerhans cells associated with neoplastic cells, cytoplasmic hyaline globules, lipid droplets, glycogen, and cytoplasmic crystals. Only a few of these ultrastructural features are absolutely specific. Relatively specific immunohistochemical tests used to diagnose metastatic adenocarcinomas of unknown primary origin include prostate-specific antigen, thyroglobulin, estrogen and progesterone receptor proteins, thyroid transcription factor-I, and surfactant apoproteins. Of these, prostate-specific antigen and thyroglobulin are the most specific. The purpose of this article is to discuss the use of electron microscopy and immunohistochemistry in the site-specific diagnosis of metastatic adenocarcinomas of unknown primary origin.

  5. A Review of Ideas Concerning Life Origin

    NASA Astrophysics Data System (ADS)

    Gindilis, L. M.

    2014-10-01

    Since the times of Antiquity the and for a long time the idea of self-origination of life was the dominant one. It reappeared again after microorganisms were discovered (XVII century). The possibility of abiogenesis at microbial level was discussed for more than a century. Pateur demonstrated that spontaneous origination of microorganisms in sterile broth was due to those same microorganisms transported by dust particles. Thus proving that every form of life originates from the parental life form. So the question arises: how did the first microorganisms appear on the Earth. There are three possible versions: 1) accidental origination of a viable form; 2) primal organisms were transported to the Earth from outer space; 3) they were formed on the Earth in the process of prebiotic chemical evolution. We discuss the problems of prebiotic evolution from simple monomers up to living cells. An important item of nowadays conceptions of life origination is the hypothesis of the ancient world of RNA as possible precursor of life on Earth. The discovery in carbonaceous chondrites of traces of bacterial life evidences the existence of life in the Solar System even before the formation of the Earth. The idea of life as brought to the Earth out of Cosmos originated under the impression of self-origination hypothesis downfall. It went through several stages (Helmholtz, W. Thompson, XIX century; Arrhenius, early XX century; Hoyle and Wickramasinghe, second half of XX century) and presently evokes constantly growing interest. The panspermia theory does not solve the problem of origination of life, only moves it onto other planets. According to V.A. Mazur, the probability of accidental formation of RNA molecule is negligible not only on the Earth, but in the whole Universe over all the time span of its existence. But it is practically equal to unit in the domain formed at the inflation stage of the evolution of the Universe. A.D.Panov considered panspermia in the Galaxy at the level

  6. The evolutionary origin and diversification of feathers.

    PubMed

    Prum, Richard O; Brush, Alan H

    2002-09-01

    Progress on the evolutionary origin and diversification of feathers has been hampered by conceptual problems and by the lack of plesiomorphic feather fossils. Recently, both of these limitations have been overcome by the proposal of the developmental theory of the origin of feathers, and the discovery of primitive feather fossils on nonavian theropod dinosaurs. The conceptual problems of previous theories of the origin of feathers are reviewed, and the alternative developmental theory is presented and discussed. The developmental theory proposes that feathers evolved through a series of evolutionary novelties in developmental mechanisms of the follicle and feather germ. The discovery of primitive and derived fossil feathers on a diversity of coelurosaurian theropod dinosaurs documents that feathers evolved and diversified in nonavian theropods before the origin of birds and before the origin of flight. The morphologies of these primitive feathers are congruent with the predictions of the developmental theory. Alternatives to the theropod origin of feathers are critique and rejected. Hypotheses for the initial function of feathers are reviewed. The aerodynamic theory of feather origins is falsified, but many other functions remain developmentally and phylogenetically plausible. Whatever their function, feathers evolved by selection for a follicle that would grow an emergent tubular appendage. Feathers are inherently tubular structures. The homology of feathers and scales is weakly supported. Feathers are composed of a suite of evolutionary novelties that evolved by the duplication, hierarchical organization, interaction, dissociation, and differentiation of morphological modules. The unique capacity for modular subdivision of the tubular feather follicle and germ has fostered the evolution of numerous innovations that characterize feathers. The evolution of feather keratin and the molecular basis of feather development are also discussed.

  7. The origin of mesoderm in phoronids

    NASA Technical Reports Server (NTRS)

    Freeman, Gary; Martindale, Mark Q.

    2002-01-01

    Descriptive studies of phoronid development have concluded that the mesoderm of these animals originates from the endoderm during gastrulation. This interpretation has been tested by labeling one blastomere of 4- through 16-cell embryos and examining the position and germ layers occupied by the labeled clones of cells in the larva. No 2 injections gave rise to identical clones of cells, suggesting that the cleavage program does not generate cells of unique identity and that cell fates are established at later developmental time points. In many cases, a relatively large sector composed of ectodermal cells was labeled. When these labeled cells were adjacent to the mouth or anus of the larva, muscle and mesenchyme cells originated from the labeled clones. Under these circumstances, nerve cells also originated from these labeled sectors. These labeling studies also showed that endodermal cells can give rise to mesodermal and neural cells. These results suggest that nerve and muscle cells are induced to form at ectodermal-endodermal boundaries from both germ layers. These marking experiments also confirmed the observation that nerve cells originate both from the apical organ and the trunk region and show for the first time that the intestine originates by ingression of posterior ectoderm.

  8. The precise temporal calibration of dinosaur origins

    NASA Astrophysics Data System (ADS)

    Marsicano, Claudia A.; Irmis, Randall B.; Mancuso, Adriana C.; Mundil, Roland; Chemale, Farid

    2016-01-01

    Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary.

  9. The precise temporal calibration of dinosaur origins.

    PubMed

    Marsicano, Claudia A; Irmis, Randall B; Mancuso, Adriana C; Mundil, Roland; Chemale, Farid

    2016-01-19

    Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U-Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic-Jurassic boundary.

  10. Two maternal origins of Chinese domestic goose.

    PubMed

    Li, H F; Zhu, W Q; Chen, K W; H, Y; Xu, W J; Song, W

    2011-12-01

    China is particularly rich in goose genetic resources. Systematic study of the genetic diversity and origin of Chinese domestic geese will provide an important scientific basis for the conservation and utilization of these resources and for human history. The 521-bp control region (D-loop) of mitochondrial DNA from 26 goose breeds and 6 Landaise geese were sequenced. The results showed that the average haplotype diversity and nucleotide diversity of Chinese domestic geese were 0.1384 and 0.00029, respectively. Shared haplotype analysis and systematic evolution analysis revealed that Chinese domestic geese had 2 maternal origins. The Yili goose breed originated from the Greylag goose (Anser anser), and the other 25 domestic goose breeds originated from the swan goose (Anser cygnoides). An interesting finding was that 1 Linxian white goose and 1 Wanxi white goose shared the same H4 haplotype with the Rhine goose and the Landaise goose, which originated from the Greylag goose (A. anser). Further research on this finding is planned.

  11. An integrative approach to understanding bird origins.

    PubMed

    Xu, Xing; Zhou, Zhonghe; Dudley, Robert; Mackem, Susan; Chuong, Cheng-Ming; Erickson, Gregory M; Varricchio, David J

    2014-12-12

    Recent discoveries of spectacular dinosaur fossils overwhelmingly support the hypothesis that birds are descended from maniraptoran theropod dinosaurs, and furthermore, demonstrate that distinctive bird characteristics such as feathers, flight, endothermic physiology, unique strategies for reproduction and growth, and a novel pulmonary system originated among Mesozoic terrestrial dinosaurs. The transition from ground-living to flight-capable theropod dinosaurs now probably represents one of the best-documented major evolutionary transitions in life history. Recent studies in developmental biology and other disciplines provide additional insights into how bird characteristics originated and evolved. The iconic features of extant birds for the most part evolved in a gradual and stepwise fashion throughout archosaur evolution. However, new data also highlight occasional bursts of morphological novelty at certain stages particularly close to the origin of birds and an unavoidable complex, mosaic evolutionary distribution of major bird characteristics on the theropod tree. Research into bird origins provides a premier example of how paleontological and neontological data can interact to reveal the complexity of major innovations, to answer key evolutionary questions, and to lead to new research directions. A better understanding of bird origins requires multifaceted and integrative approaches, yet fossils necessarily provide the final test of any evolutionary model.

  12. The precise temporal calibration of dinosaur origins

    PubMed Central

    Marsicano, Claudia A.; Irmis, Randall B.; Mancuso, Adriana C.; Mundil, Roland; Chemale, Farid

    2016-01-01

    Dinosaurs have been major components of ecosystems for over 200 million years. Although different macroevolutionary scenarios exist to explain the Triassic origin and subsequent rise to dominance of dinosaurs and their closest relatives (dinosauromorphs), all lack critical support from a precise biostratigraphically independent temporal framework. The absence of robust geochronologic age control for comparing alternative scenarios makes it impossible to determine if observed faunal differences vary across time, space, or a combination of both. To better constrain the origin of dinosaurs, we produced radioisotopic ages for the Argentinian Chañares Formation, which preserves a quintessential assemblage of dinosaurian precursors (early dinosauromorphs) just before the first dinosaurs. Our new high-precision chemical abrasion thermal ionization mass spectrometry (CA-TIMS) U–Pb zircon ages reveal that the assemblage is early Carnian (early Late Triassic), 5- to 10-Ma younger than previously thought. Combined with other geochronologic data from the same basin, we constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs. After their origin, dinosaurs only gradually dominated mid- to high-latitude terrestrial ecosystems millions of years later, closer to the Triassic–Jurassic boundary. PMID:26644579

  13. The origin of life from primordial planets

    NASA Astrophysics Data System (ADS)

    Gibson, Carl H.; Schild, Rudolph E.; Wickramasinghe, N. Chandra

    2011-04-01

    The origin of life and the origin of the Universe are among the most important problems of science and they might be inextricably linked. Hydro-gravitational-dynamics cosmology predicts hydrogen-helium gas planets in clumps as the dark matter of galaxies, with millions of planets per star. This unexpected prediction is supported by quasar microlensing of a galaxy and a flood of new data from space telescopes. Supernovae from stellar over-accretion of planets produce the chemicals (C, N, O, P, etc.) and abundant liquid-water domains required for first life and the means for wide scattering of life prototypes. Life originated following the plasma-to-gas transition between 2 and 20 Myr after the big bang, while planetary core oceans were between critical and freezing temperatures, and interchanges of material between planets constituted essentially a cosmological primordial soup. Images from optical, radio and infrared space telescopes suggest life on Earth was neither first nor inevitable.

  14. Origin of extra chromosome in Patau syndrome.

    PubMed

    Ishikiriyama, S; Niikawa, N

    1984-01-01

    Five live-born infants with Patau syndrome were studied for the nondisjunctional origin of the extra chromosome. Transmission modes of chromosomes 13 from parents to a child were determined using both QFQ- and RFA-heteromorphisms as markers, and the origin was ascertained in all of the patients. The extra chromosome had originated in nondisjunction at the maternal first meiotic division in two patients, at the maternal second meiosis in other two, and at the paternal first meiosis in the remaining one. Summarizing the results of the present study, together with those of the previous studies on a liveborn and abortuses with trisomy 13, nondisjunction at the maternal and the paternal meiosis occurred in this trisomy in the ratio of 14:3. This ratio is not statistically different from that inferred from the previous studies for Down syndrome. These findings suggest that there may be a fundamental mechanism common to the occurrence of nondisjunction in the acrocentric trisomies.

  15. Symbiosis and the origin of eukaryotic motility

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Hinkle, G.

    1991-01-01

    Ongoing work to test the hypothesis of the origin of eukaryotic cell organelles by microbial symbioses is discussed. Because of the widespread acceptance of the serial endosymbiotic theory (SET) of the origin of plastids and mitochondria, the idea of the symbiotic origin of the centrioles and axonemes for spirochete bacteria motility symbiosis was tested. Intracellular microtubular systems are purported to derive from symbiotic associations between ancestral eukaryotic cells and motile bacteria. Four lines of approach to this problem are being pursued: (1) cloning the gene of a tubulin-like protein discovered in Spirocheata bajacaliforniesis; (2) seeking axoneme proteins in spirochets by antibody cross-reaction; (3) attempting to cultivate larger, free-living spirochetes; and (4) studying in detail spirochetes (e.g., Cristispira) symbiotic with marine animals. Other aspects of the investigation are presented.

  16. The origin of modern terrestrial life

    PubMed Central

    Forterre, Patrick; Gribaldo, Simonetta

    2007-01-01

    The study of the origin of life covers many areas of expertise and requires the input of various scientific communities. In recent years, this research field has often been viewed as part of a broader agenda under the name of “exobiology” or “astrobiology.” In this review, we have somewhat narrowed this agenda, focusing on the origin of modern terrestrial life. The adjective “modern” here means that we did not speculate on different forms of life that could have possibly appeared on our planet, but instead focus on the existing forms (cells and viruses). We try to briefly present the state of the art about alternative hypotheses discussing not only the origin of life per se, but also how life evolved to produce the modern biosphere through a succession of steps that we would like to characterize as much as possible. PMID:19404443

  17. Developmental plasticity and the origin of tetrapods.

    PubMed

    Standen, Emily M; Du, Trina Y; Larsson, Hans C E

    2014-09-04

    The origin of tetrapods from their fish antecedents, approximately 400 million years ago, was coupled with the origin of terrestrial locomotion and the evolution of supporting limbs. Polypterus is a member of the basal-most group of ray-finned fish (actinopterygians) and has many plesiomorphic morphologies that are comparable to elpistostegid fishes, which are stem tetrapods. Polypterus therefore serves as an extant analogue of stem tetrapods, allowing us to examine how developmental plasticity affects the 'terrestrialization' of fish. We measured the developmental plasticity of anatomical and biomechanical responses in Polypterus reared on land. Here we show the remarkable correspondence between the environmentally induced phenotypes of terrestrialized Polypterus and the ancient anatomical changes in stem tetrapods, and we provide insight into stem tetrapod behavioural evolution. Our results raise the possibility that environmentally induced developmental plasticity facilitated the origin of the terrestrial traits that led to tetrapods.

  18. The origin of the vertebrate skeleton

    NASA Astrophysics Data System (ADS)

    Pivar, Stuart

    2011-01-01

    The anatomy of the human and other vertebrates has been well described since the days of Leonardo da Vinci and Vesalius. The causative origin of the configuration of the bones and of their shapes and forms has been addressed over the ensuing centuries by such outstanding investigators as Goethe, Von Baer, Gegenbauer, Wilhelm His and D'Arcy Thompson, who sought to apply mechanical principles to morphogenesis. However, no coherent causative model of morphogenesis has ever been presented. This paper presents a causative model for the origin of the vertebrate skeleton, based on the premise that the body is a mosaic enlargement of self-organized patterns engrained in the membrane of the egg cell. Drawings illustrate the proposed hypothetical origin of membrane patterning and the changes in the hydrostatic equilibrium of the cytoplasm that cause topographical deformations resulting in the vertebrate body form.

  19. Book Review: The Origins of Comets

    NASA Technical Reports Server (NTRS)

    McKay, Christopher P.

    1992-01-01

    In The Origins of Comets, Bailey, Clube, and Napier propose that the answer to whether the ancient heavens were more interesting is a resounding "yes." The sky, in fact, has changed and is still changing. The authors trace the study of comets back to ancient Babylonian times with a focus on theories of the origins of these enigmatic visitors. The book is really of three distinct parts: the first six chapters provide an excellent and delightfully readable historical account of comet studies up to this century. The next few chapters give a rather detailed treatment of current models for comet origins. The last section treats the authors' own theories about the relationship between giant comets and extinctions on Earth.

  20. Origin of strong dispersion in Hubbard insulators

    DOE PAGES

    Wang, Y.; Wohlfeld, K.; Moritz, B.; ...

    2015-08-10

    Using cluster perturbation theory, we explain the origin of the strongly dispersive feature found at high binding energy in the spectral function of the Hubbard model. By comparing the Hubbard and $t₋J₋3s$ model spectra, we show that this dispersion does not originate from either coupling to spin fluctuations ($∝ J$ ) or the free hopping ($∝ t$ ). Instead, it should be attributed to a long-range, correlated hopping $∝ t²/U$ which allows an effectively free motion of the hole within the same antiferromagnetic sublattice. This origin explains both the formation of the high-energy anomaly in the single-particle spectrum and themore » sensitivity of the high-binding-energy dispersion to the next-nearest-neighbor hopping $t'$ .« less

  1. Origin of strong dispersion in Hubbard insulators

    SciTech Connect

    Wang, Y.; Wohlfeld, K.; Moritz, B.; Jia, C. J.; van Veenendaal, M.; Wu, K.; Chen, C. -C.; Devereaux, T. P.

    2015-08-10

    Using cluster perturbation theory, we explain the origin of the strongly dispersive feature found at high binding energy in the spectral function of the Hubbard model. By comparing the Hubbard and $t₋J₋3s$ model spectra, we show that this dispersion does not originate from either coupling to spin fluctuations ($∝ J$ ) or the free hopping ($∝ t$ ). Instead, it should be attributed to a long-range, correlated hopping $∝ t²/U$ which allows an effectively free motion of the hole within the same antiferromagnetic sublattice. This origin explains both the formation of the high-energy anomaly in the single-particle spectrum and the sensitivity of the high-binding-energy dispersion to the next-nearest-neighbor hopping $t'$ .

  2. Cosmic Origins Program Annual Technology Report

    NASA Technical Reports Server (NTRS)

    Pham, Bruce Thai; Neff, Susan Gale

    2016-01-01

    What is the Cosmic Origins (COR) Program? From ancient times, humans have looked up at the night sky and wondered: Are we alone? How did the universe come to be? How does the universe work? COR focuses on the second question. Scientists investigating this broad theme seek to understand the origin and evolution of the universe from the Big Bang to the present day, determining how the expanding universe grew into a grand cosmic web of dark matter enmeshed with galaxies and pristine gas, forming, merging, and evolving over time.

  3. Origin of the cell - Experiments and premises

    NASA Technical Reports Server (NTRS)

    Fox, S. W.

    1973-01-01

    Theories and component concepts of the origin of life, i.e., primordial life, have emerged from (1) constructionistic studies on model materials and systems, and (2) reductionistic studies of contemporary cells. The resultant views conflict in a number of aspects; many of the differences are analyzed in this article. Constructionistic experiments are appropriate to asking questions about origins since they are in the same direction as evolution itself. These experiments have revealed self-ordering properties and associated emergent functions, which were not predictable.

  4. The physical origin of hydrophobic effects

    NASA Astrophysics Data System (ADS)

    Sun, Qiang

    2017-03-01

    From the structural studies on water and air/water interface, hydration free energy is derived, and used to investigate the origin of hydrophobic effects. As a solute is dissolved into water, hydration free energy increases, and is divided into initial and hydrophobic solvation processes. In the initial process, hydration free energy is dominated by hydrogen bonding in interfacial water (topmost water layer at solute/water interface). For hydrophobic process, hydration free energy is related to the hydrogen bonding in bulk and interfacial water. Therefore, hydrophobic effects originate from the structural competition between hydrogen bonding in bulk water and that in interfacial water.

  5. RNA catalysis and the origins of life

    NASA Technical Reports Server (NTRS)

    Orgel, Leslie E.

    1986-01-01

    The role of RNA catalysis in the origins of life is considered in connection with the discovery of riboszymes, which are RNA molecules that catalyze sequence-specific hydrolysis and transesterification reactions of RNA substrates. Due to this discovery, theories positing protein-free replication as preceding the appearance of the genetic code are more plausible. The scope of RNA catalysis in biology and chemistry is discussed, and it is noted that the development of methods to select (or predict) RNA sequences with preassigned catalytic functions would be a major contribution to the study of life's origins.

  6. Origins of the protein synthesis cycle

    NASA Technical Reports Server (NTRS)

    Fox, S. W.

    1981-01-01

    Largely derived from experiments in molecular evolution, a theory of protein synthesis cycles has been constructed. The sequence begins with ordered thermal proteins resulting from the self-sequencing of mixed amino acids. Ordered thermal proteins then aggregate to cell-like structures. When they contained proteinoids sufficiently rich in lysine, the structures were able to synthesize offspring peptides. Since lysine-rich proteinoid (LRP) also catalyzes the polymerization of nucleoside triphosphate to polynucleotides, the same microspheres containing LRP could have synthesized both original cellular proteins and cellular nucleic acids. The LRP within protocells would have provided proximity advantageous for the origin and evolution of the genetic code.

  7. Metabolic symbiosis at the origin of eukaryotes.

    PubMed

    López-Garćia, P; Moreira, D

    1999-03-01

    Thirty years after Margulis revived the endosymbiosis theory for the origin of mitochondria and chloroplasts, two novel symbiosis hypotheses for the origin of eukaryotes have been put forward. Both propose that eukaryotes arose through metabolic symbiosis (syntrophy) between eubacteria and methanogenic Archaea. They also propose that this was mediated by interspecies hydrogen transfer and that, initially, mitochondria were anaerobic. These hypotheses explain the mosaic character of eukaryotes (i.e. an archaeal-like genetic machinery and a eubacterial-like metabolism), as well as distinct eukaryotic characteristics (which are proposed to be products of symbiosis). Combined data from comparative genomics, microbial ecology and the fossil record should help to test their validity.

  8. Mapping Replication Origin Sequences in Eukaryotic Chromosomes

    PubMed Central

    Fu, Haiqing; Besnard, Emilie; Desprat, Romain; Ryan, Michael; Kahli, Malik; Lemaitre, Jean-Marc; Aladjem, Mirit I.

    2014-01-01

    Recent advances in genome sequencing technology have led towards the complete mapping of DNA replication initiation sites in the human genome. This thorough origin mapping facilitates the understanding of the relationship between replication initiation events, transcription and chromatin modifications and allows the characterization of consensus sequences of potential replication origins. This unit provides a detailed protocol for isolation and sequence analyses of nascent DNA strands. Two variations of the protocol based on non-overlapping assumptions are described below, addressing potential bias issues for whole genome analyses. PMID:25447077

  9. Origin of collision-induced molecular orientation.

    PubMed

    Brouard, M; Hornung, B; Aoiz, F J

    2013-11-01

    Collision-induced rotational angular momentum orientation is a fundamental property of molecular scattering, which is sensitive to the balance between attractive and repulsive forces at play during collision. Here, we quantify a new mechanism leading to orientation, which is purely quantum mechanical in origin. Although the new mechanism is quite general, and will operate more widely in atomic and molecular scattering, it is observed here for impulsive hard shell collisions, for which the orientation vanishes classically. The quantum mechanism can thus be studied in isolation from other processes. The orientation is proposed to originate from the nonlocal nature of the quantum mechanical collision encounter.

  10. The complex origin of Astyanax cavefish

    PubMed Central

    2012-01-01

    Background The loss of phenotypic characters is a common feature of evolution. Cave organisms provide excellent models for investigating the underlying patterns and processes governing the evolutionary loss of phenotypic traits. The blind Mexican cavefish, Astyanax mexicanus, represents a particularly strong model for both developmental and genetic analyses as these fish can be raised in the laboratory and hybridized with conspecific surface form counterparts to produce large F2 pedigrees. As studies have begun to illuminate the genetic bases for trait evolution in these cavefish, it has become increasingly important to understand these phenotypic changes within the context of cavefish origins. Understanding these origins is a challenge. For instance, widespread convergence on similar features renders morphological characters less informative. In addition, current and past gene flow between surface and cave forms have complicated the delineation of particular cave populations. Results Past population-level analyses have sought to: 1) estimate at what time in the geological past cave forms became isolated from surface-dwelling ancestors, 2) define the extent to which cave form populations originated from a common invasion (single origin hypothesis) or several invasions (multiple origin hypothesis), and 3) clarify the role of geological and climatic events in Astyanax cavefish evolution. In recent years, thanks to the combined use of morphological and genetic data, a much clearer picture has emerged regarding the origins of Astyanax cavefish. Conclusions The consensus view, based on several recent studies, is that cave forms originated from at least two distinct ancestral surface-dwelling stocks over the past several million years. In addition, each stock gave rise to multiple invasions of the subterranean biotope. The older stock is believed to have invaded the El Abra caves at least three times while the new stock separately invaded the northern Guatemala and

  11. 31 CFR 248.6 - Recovery of original check.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 2 2011-07-01 2011-07-01 false Recovery of original check. 248.6... § 248.6 Recovery of original check. (a) If the claimant recovers an original check after he has... substitute check has been received prior to the recovery of the original check, the original check should...

  12. 31 CFR 248.6 - Recovery of original check.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Recovery of original check. 248.6... § 248.6 Recovery of original check. (a) If the claimant recovers an original check after he has... substitute check has been received prior to the recovery of the original check, the original check should...

  13. 32 CFR 1802.23 - Response by originator(s) and/or any interested party.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Response by originator(s) and/or any interested party. 1802.23 Section 1802.23 National Defense Other Regulations Relating to National Defense NATIONAL COUNTERINTELLIGENCE CENTER CHALLENGES TO CLASSIFICATION OF DOCUMENTS BY AUTHORIZED HOLDERS PURSUANT TO SECTION 1.9...

  14. 32 CFR 1802.23 - Response by originator(s) and/or any interested party.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 6 2011-07-01 2011-07-01 false Response by originator(s) and/or any interested party. 1802.23 Section 1802.23 National Defense Other Regulations Relating to National Defense NATIONAL COUNTERINTELLIGENCE CENTER CHALLENGES TO CLASSIFICATION OF DOCUMENTS BY AUTHORIZED HOLDERS PURSUANT TO SECTION 1.9...

  15. 32 CFR 1802.23 - Response by originator(s) and/or any interested party.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Response by originator(s) and/or any interested party. 1802.23 Section 1802.23 National Defense Other Regulations Relating to National Defense NATIONAL COUNTERINTELLIGENCE CENTER CHALLENGES TO CLASSIFICATION OF DOCUMENTS BY AUTHORIZED HOLDERS PURSUANT TO SECTION 1.9...

  16. 32 CFR 1802.23 - Response by originator(s) and/or any interested party.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Response by originator(s) and/or any interested party. 1802.23 Section 1802.23 National Defense Other Regulations Relating to National Defense NATIONAL COUNTERINTELLIGENCE CENTER CHALLENGES TO CLASSIFICATION OF DOCUMENTS BY AUTHORIZED HOLDERS PURSUANT TO SECTION 1.9...

  17. 32 CFR 1802.23 - Response by originator(s) and/or any interested party.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Response by originator(s) and/or any interested party. 1802.23 Section 1802.23 National Defense Other Regulations Relating to National Defense NATIONAL COUNTERINTELLIGENCE CENTER CHALLENGES TO CLASSIFICATION OF DOCUMENTS BY AUTHORIZED HOLDERS PURSUANT TO SECTION 1.9...

  18. 21. Photographic contact print from a 8x10 original negative. (Original ...

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

    21. Photographic contact print from a 8x10 original negative. (Original drawing located on abandoned NASA site, currently owned by the City of Downey, Downey, California). 1954 NORTH AMERICAN AVIATION BUILDING 41 CONSTRUCTION LAYOUT. - NASA Industrial Plant, Missile Research Laboratory, 12214 Lakewood Boulevard, Downey, Los Angeles County, CA

  19. Exploring the Divergent Academic Outcomes of U.S.-Origin and Immigrant-Origin Black Undergraduates

    ERIC Educational Resources Information Center

    Tauriac, Jesse J.; Liem, Joan H.

    2012-01-01

    To explore the divergent academic experiences and outcomes of U.S.-origin and immigrant-origin Black Americans, we drew on Tinto's (1993) model of persistence to test a 3-wave longitudinal model of college persistence using path analysis. Our sample comprised 101 ethnically diverse Black students who were randomly selected from 9 public high…

  20. 8. Photographic contact print from a 8x10 original negative. (Original ...

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

    8. Photographic contact print from a 8x10 original negative. (Original drawing located on abandoned NASA site, currently owned by the City of Downey, Downey, California). 1956 RECORD DRAWINGS. NORTH AMERICAN AVAIATION INC, INDUSTRIAL ENGINEERS. 1956 BLDG 25 & BLDG 42 ELEVATIONS. - NASA Industrial Plant, Storage Facility, 12214 Lakewood Boulevard, Downey, Los Angeles County, CA

  1. 16. Photographic contact print from a 8x10 original negative. (Original ...

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

    16. Photographic contact print from a 8x10 original negative. (Original drawing located on abandoned NASA site, currently owned by the City of Downey, Downey, California). 1956 RECORD DRAWINGS. NORTH AMERICAN AVAIATION INC, INDUSTRIAL ENGINEERS. BLDGS 10, 25, & 42 ELEVATIONS & FLOOR PLANS. - NASA Industrial Plant, Maintenance Facility, 12214 Lakewood Boulevard, Downey, Los Angeles County, CA

  2. Origins of rainbow smelt in Lake Ontario

    USGS Publications Warehouse

    Bergstedt, Roger A.

    1983-01-01

    The first rainbow smelt (Osmerus mordax) to enter Lake Ontario were probably migrants from an anadromous strain introduced into New York's Finger Lakes. Since the upper Great Lakes were originally stocked with a landlocked strain from Green Lake, Maine, subsequent migration to Lake Ontario from Lake Erie makes Lake Ontario unique among the Great Lakes in probably having received introductions from two distinct populations.

  3. Cosmic Ray Origin, Acceleration and Propagation

    NASA Technical Reports Server (NTRS)

    Baring, Matthew G.

    2000-01-01

    This paper summarizes highlights of the OG3.1, 3.2 and 3.3 sessions of the 26th International Cosmic Ray Conference in Salt Lake City, which were devoted to issues of origin/composition, acceleration and propagation.

  4. Action Research: Its Origins and Early Application.

    ERIC Educational Resources Information Center

    Cook, Stuart W.

    This paper contains informal remarks on action research in social psychology from its post World War II origins to its current status. Kurt Lewin first described action research in the 1946 article, "Action Research and Minority Problems," as a three-step process of program planning, program execution, and follow-up evaluation. Ronald Lippitt and…

  5. The Complex Origins of the Registrar

    ERIC Educational Resources Information Center

    Smith, Shawn C.

    2012-01-01

    The origins of the registrar's office are complex. According to common tradition, the registrar was, or evolved from, the office of the beadle (sometimes referred to as "bedel") in the medieval university. This tradition is incorrect; the story is more complex. The beadle sometimes performed functions similar to those performed by the…

  6. 19 CFR 10.914 - Originating goods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Originating goods. 10.914 Section 10.914 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion...

  7. 19 CFR 10.914 - Originating goods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Originating goods. 10.914 Section 10.914 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion...

  8. 19 CFR 10.914 - Originating goods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Originating goods. 10.914 Section 10.914 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Peru Trade Promotion...

  9. Original Sin and T. E. Hulme's Aesthetics

    ERIC Educational Resources Information Center

    Kishler, Thomas C.

    1976-01-01

    T. E. Hulme, a vigorous opponent of romanticism in art, poetry, and philosophy, insisted that the underlying flaw of the romantic view was its rejection of the dogma of Original Sin and the fall of man. His views are explored for the significant bearing they have on the development of aesthetic insight and indirectly on value and outlook.…

  10. 19 CFR 10.1014 - Originating goods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Originating goods. 10.1014 Section 10.1014 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Korea Free Trade Agreement...

  11. 19 CFR 10.1014 - Originating goods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Originating goods. 10.1014 Section 10.1014 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Korea Free Trade Agreement...

  12. 19 CFR 10.1014 - Originating goods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Originating goods. 10.1014 Section 10.1014 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Korea Free Trade Agreement...

  13. [Schopenhauer as the originator of Freudian metapsychology].

    PubMed

    Gödde, G

    1991-11-01

    The influence of 19th century philosophy on Freud's thought is to this day underestimated in comparison with the influence of the scientific theories. Gödde vindicates Max Horkheimer's proposition that Freud was "in certain respects a successor to Schopenhauer" even though Freud knew Schopenhauer (and Nietzsche) through secondary literature rather than through the original writings.

  14. Acid Rain Students Do Original Research.

    ERIC Educational Resources Information Center

    Outdoor Communicator, 1984

    1984-01-01

    At Park Senior High School (Cottage Grove, Minnesota), 46 juniors and seniors planted 384 red pine seedlings in connection with their original research on acid rain, with advice from Dr. Harriet Stubbs, director of the Acid Precipitation Awareness Program (West Saint Paul), which has been developing acid rain teaching materials. (MH)

  15. Mosaic origin of the mitochondrial proteome.

    PubMed

    Szklarczyk, Radek; Huynen, Martijn A

    2010-11-01

    Although the origin of mitochondria from the endosymbiosis of an α-proteobacterium is well established, the nature of the host cell, the metabolic complexity of the endosymbiont and the subsequent evolution of the proto-mitochondrion into all its current appearances are still the subject of discovery and sometimes debate. Here we review what has been inferred about the original composition and subsequent evolution of the mitochondrial proteome and essential mitochondrial systems. The evolutionary mosaic that currently constitutes mitochondrial proteomes contains (i) endosymbiotic proteins (15-45%), (ii) proteins without detectable orthologs outside the eukaryotic lineage (40%), and (iii) proteins that are derived from non-proteobacterial Bacteria, Bacteriophages and Archaea (15%, specifically multiple tRNA-modification proteins). Protein complexes are of endosymbiotic origin, but have greatly expanded with novel eukaryotic proteins; in contrast to mitochondrial enzymes that are both of proteobacterial and non-proteobacterial origin. This disparity is consistent with the complexity hypothesis, which argues that proteins that are a part of large, multi-subunit complexes are unlikely to undergo horizontal gene transfer. We observe that they neither change their subcellular compartments in the course of evolution, even when their genes do.

  16. Photosynthesis: what color was its origin?

    PubMed

    Xiong, Jin

    2006-01-01

    Recent studies using geological and molecular phylogenetic evidence suggest several alternative evolutionary scenarios for the origin of photosynthesis. The earliest photosynthetic group is variously thought to be heliobacteria, proteobacteria or a precursor of cyanobacteria, organisms whose photosynthetic pigments make them different colors.

  17. 19 CFR 10.770 - Originating goods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Originating goods. 10.770 Section 10.770 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  18. The Origins of the University Grants Committee

    ERIC Educational Resources Information Center

    Hutchinson, Eric

    1975-01-01

    This historical study of the British University Grants Committee, focusing on its origins and establishment in 1919, concludes that despite recent criticism no country has created a grant-awarding body so free from political interference and prejudice for supporting its universities at the state or federal level. (JT)

  19. Search for the Origin of Life

    ERIC Educational Resources Information Center

    Brown, R. D.

    1975-01-01

    Presents various ideas on the origin of life including very early ideas, Oparin's view, and an alternative view related to carbonaceous chondrites. Outlines one currently tenable hypothesis in the formation of the solar system and explains the method involved in detecting polyatomic molecules in dark nebulae. (GS)

  20. Photosynthesis and the Origin of Life

    NASA Astrophysics Data System (ADS)

    Hartman, Hyman

    1998-10-01

    The origin and evolution of photosynthesis is considered to be the key to the origin of life. This eliminates the need for a soup as the synthesis of the bioorganics are to come from the fixation of carbon dioxide and nitrogen. No soup then no RNA world or Protein world. Cyanobacteria have been formed by the horizontal transfer of green sulfur bacterial photoreaction center genes by means of a plasmid into a purple photosynthetic bacterium. The fixation of carbon dioxide is considered to have evolved from a reductive dicarboxylic acid cycle (Chloroflexus) which was then followed by a reductive tricarboxylic acid cycle (Chlorobium) and finally by the reductive pentose phosphate cycle (Calvin cycle). The origin of life is considered to have occurred in a hot spring on the outgassing early earth. The first organisms were self-replicating iron-rich clays which fixed carbon dioxide into oxalic and other dicarboxylic acids. This system of replicating clays and their metabolic phenotype then evolved into the sulfide rich region of the hotspring acquiring the ability to fix nitrogen. Finally phosphate was incorporated into the evolving system which allowed the synthesis of nucleotides and phospholipids. If biosynthesis recapitulates biopoesis, then the synthesis of amino acids preceded the synthesis of the purine and pyrimidine bases. Furthermore the polymerization of the amino acid thioesters into polypeptides preceded the directed polymerization of amino acid esters by polynucleotides. Thus the origin and evolution of the genetic code is a late development and records the takeover of the clay by RNA.

  1. Language Origin from an Emergentist Perspective

    ERIC Educational Resources Information Center

    Ke, Jinyun; Holland, John H.

    2006-01-01

    In recent decades, there has been a surge of interest in the origin of language across a wide range of disciplines. Emergentism provides a new perspective to integrate investigations from different areas of study. This paper discusses how the study of language acquisition can contribute to the inquiry, in particular when computer modeling is…

  2. 21 CFR 814.104 - Original applications.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) MEDICAL DEVICES PREMARKET APPROVAL OF MEDICAL DEVICES Humanitarian Use Devices § 814.104 Original... Development (in accordance with § 814.102) that the device qualifies as a HUD; (2) An explanation of why the device would not be available unless an HDE were granted and a statement that no comparable device...

  3. 21 CFR 814.104 - Original applications.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) MEDICAL DEVICES PREMARKET APPROVAL OF MEDICAL DEVICES Humanitarian Use Devices § 814.104 Original... Development (in accordance with § 814.102) that the device qualifies as a HUD; (2) An explanation of why the device would not be available unless an HDE were granted and a statement that no comparable device...

  4. 21 CFR 814.104 - Original applications.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...) MEDICAL DEVICES PREMARKET APPROVAL OF MEDICAL DEVICES Humanitarian Use Devices § 814.104 Original... determination made by FDA's Office of Orphan Products Development (in accordance with § 814.102) that the device qualifies as a HUD; (2) An explanation of why the device would not be available unless an HDE were...

  5. 19 CFR 10.810 - Originating goods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., that has been grown, produced, or manufactured in the territory of one or both of the Parties, is... considered an originating good under the BFTA only if the sum of the value of materials produced in one or... having undergone simple combining or packaging operations, or mere dilution with water or...

  6. Origin and Properties of Prostatic Stem Cells

    DTIC Science & Technology

    2005-02-01

    express (6 integrin which is also found on many primitive cell types. We also show that SP cells have a greater proliferative capacity than non-SP cells as expected if SP cells are of more primitive origin than non-SP cells.

  7. The origin of granites and related rocks

    USGS Publications Warehouse

    Brown, Michael; Piccoli, Philip M.

    1995-01-01

    This Circular is a compilation of abstracts for posters and oral presentations given at the third Hutton symposium on the Origin of granites and related rocks. The symposium was co-sponsored by the Department of Geology, University of Maryland at College Park; the U.S. Geological Survey, Reston, Virginia; and the Department of Terrestrial Magnetism and Geophysical Laboratory, Carnegie Institution of Washington.

  8. Origins of food crops connect countries worldwide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research into the origins of food plants has led to the recognition that specific geographic regions around the world have been of particular importance to the development of agricultural crops. Yet the relative contributions of these different regions in the context of current food systems have not...

  9. On the Origin of Hypervelocity Stars

    NASA Astrophysics Data System (ADS)

    Yu, Q.; Lu, Y.

    2011-05-01

    Hypervelocity stars (HVSs) moving in the Galactic halo are mainly B-type stars with origin of their progenitors unknown. OB stars are also populated in the Galactic Center (GC), with many being hosted in a clockwise rotating young stellar (CWS) disk within half a parsec from the central massive black hole (MBH) and their formation remaining puzzles. We find that the majority of the detected HVSs are spatially correlated with the plane of the stellar disk. By demonstrating that HVSs can well memorize the injecting direction of their progenitors, we conclude that most of the HVSs probably originate from the CWS disk. Our results not only confirm the GC origin of HVSs but also imply that the central disk should persist or be frequently rejuvenated over the past 200 Myr, which adds a new challenge to the stellar disk formation and provides insights to the longstanding problem of gas fueling into MBHs. A future survey of HVSs in the southern hemisphere will provide a check for the origin of HVSs.

  10. Particle dynamics in the original Schwarzschild metric

    NASA Astrophysics Data System (ADS)

    Fimin, N. N.; Chechetkin, V. M.

    2016-04-01

    The properties of the original Schwarzschild metric for a point gravitating mass are considered. The laws of motion in the corresponding space-time are established, and the transition from the Schwarzschildmetric to the metric of a "dusty universe" are studied. The dynamics of a system of particles in thr post-Newtonian approximation are analyzed.

  11. 19 CFR 10.770 - Originating goods.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Originating goods. 10.770 Section 10.770 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  12. 19 CFR 10.770 - Originating goods.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Originating goods. 10.770 Section 10.770 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  13. 19 CFR 10.770 - Originating goods.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Originating goods. 10.770 Section 10.770 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  14. 19 CFR 10.770 - Originating goods.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Originating goods. 10.770 Section 10.770 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY ARTICLES CONDITIONALLY FREE, SUBJECT TO A REDUCED RATE, ETC. United States-Morocco Free Trade...

  15. Origin and evolution of the Saturn system

    NASA Technical Reports Server (NTRS)

    Pollack, J. B.; Consolmagno, G.

    1983-01-01

    A review is provided of current concepts concerning the formation of the Saturn system and the subsequent history of the planet, its satellites, and rings. Emphasis is placed upon numerical models of Saturn's evolution and interior models of its satellites. Alternative theories are presented and assessed for the origins of the Saturn system, the rings of Saturn, and the atmosphere of Titan.

  16. Originalism and Subjectivism in the Bicentennial Year.

    ERIC Educational Resources Information Center

    Reid, John Phillip

    1987-01-01

    Surveys the debate over how the United States Constitution is to be regarded for purposes of judicial interpretation in federal court cases. Focuses on the views of U.S. Attorney General Edwin Meese, Ronald Dworkin, and Chief Justice William Rehnquist. Discusses the underlying values of original intent and its opposite, judicial activism.…

  17. The Origin of the Term "Hypervalent"

    ERIC Educational Resources Information Center

    Jensen, William B.

    2006-01-01

    The debate related to origin of the term "hypervalent" that was first introduced by Jeremy Musher in 1969 to describe compounds and complex ions of the heavier main-block elements in which the use of traditional Lewis 2c-2e covalent bonds requires the additional assumption of "octer expansion" for the central atom is presented. The traditional…

  18. Precambrian biota: protistan origin of trace fossils?

    PubMed

    Pawlowski, Jan; Gooday, Andrew J

    2009-01-13

    Some Precambrian trace fossils have been presented as evidence for the early origin of bilaterians; the recent finding that large amoeboid protists leave macroscopic traces at the bottom of the deep ocean questions the metazoan nature of early trace fossils, stressing the importance of single-cell organisms in Precambrian biota.

  19. Origins and Outcomes of Judgments about Work

    ERIC Educational Resources Information Center

    Johnson, Monica Kirkpatrick; Mortimer, Jeylan T.

    2011-01-01

    We evaluate the importance of judgments about work for the attainment process in the "new economy." Findings show continuing links between social origins and work orientations at age 21/22, as well as significant effects of work orientations on occupational outcomes at age 31/32. Higher socio-economic status background, and stronger…

  20. Fever of unknown origin, with a twist

    PubMed Central

    Lobo, Ronstan; Meany, Brendan; O'Hanlon, Rory; Kiernan, Thomas John

    2013-01-01

    The authors present a case of an 81-year-old man with fever of unknown origin. The case report is illustrated with the images which clarified the diagnosis in this challenging case. The cardiac MR images were of critical importance in arriving at a diagnosis of aortic root mycotic pseudoaneurysm with rupture into the right ventricle. PMID:23345531

  1. On the origin of metabolic pathways

    NASA Technical Reports Server (NTRS)

    Lazcano, A.; Miller, S. L.; Bada, J. L. (Principal Investigator)

    1999-01-01

    The heterotrophic theory of the origin of life is the only proposal available with experimental support. This comes from the ease of prebiotic synthesis under strongly reducing conditions. The prebiotic synthesis of organic compounds by reduction of CO(2) to monomers used by the first organisms would also be considered an heterotrophic origin. Autotrophy means that the first organisms biosynthesized their cell constituents as well as assembling them. Prebiotic synthetic pathways are all different from the biosynthetic pathways of the last common ancestor (LCA). The steps leading to the origin of the metabolic pathways are closer to prebiotic chemistry than to those in the LCA. There may have been different biosynthetic routes between the prebiotic and the LCAs that played an early role in metabolism but have disappeared from extant organisms. The semienzymatic theory of the origin of metabolism proposed here is similar to the Horowitz hypothesis but includes the use of compounds leaking from preexisting pathways as well as prebiotic compounds from the environment.

  2. Conflict Resolution between Mexican Origin Adolescent Siblings

    ERIC Educational Resources Information Center

    Killoren, Sarah E.; Thayer, Shawna M.; Updegraff, Kimberly A.

    2008-01-01

    We investigated correlates of adolescents' sibling conflict resolution strategies in 246, two-parent Mexican origin families. Specifically, we examined links between siblings' conflict resolution strategies and sibling dyad characteristics, siblings' cultural orientations and values, and sibling relationship qualities. Data were gathered during…

  3. Quantum mechanical effects of topological origin

    NASA Technical Reports Server (NTRS)

    Duru, I. H.

    1993-01-01

    Following a brief review of the original Casimir and Aharonov-Bohm effects, some other effects of similar natures are mentioned. A Casimir interaction between AB fluxes is presented. Possible realizations of the Casimir effects for massive charged fields in solid state structures and a new AB effect for photons are suggested.

  4. Epicardial origin of cardiac CFU-Fs.

    PubMed

    Slukvin, Igor I

    2011-12-02

    The epicardium has been recognized as a source of cardiovascular progenitors during embryogenesis and postnatal life. In this issue of Cell Stem Cell, Chong et al. (2011) identify cardiac CFU-Fs as cardiac-resident cells of epicardial origin with broad multilineage differentiation potential.

  5. Origin Stories: Geography, Culture, and Belief

    ERIC Educational Resources Information Center

    Gandy, S. Kay; Matthew, Kathleen

    2010-01-01

    At a very young age children become curious about themselves and their place in the world around them. As children mature, questions of origin signal the desire for a broader explanation of the world, a desire for a deeper understanding of something bigger than themselves to explain events that happen around them. There is a great variety of…

  6. 7 CFR 201.5 - Origin.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) FEDERAL SEED ACT FEDERAL SEED ACT REGULATIONS Records for Agricultural and Vegetable Seeds § 201.5 Origin. (a) The complete record for any lot of seed of alfalfa, red clover, white clover, or field corn, except hybrid seed corn, shall include...

  7. 19 CFR 10.303 - Originating goods.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Originating goods. 10.303 Section 10.303 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION, DEPARTMENT OF HOMELAND SECURITY; DEPARTMENT OF THE TREASURY... amended from time to time by the Customs Cooperation Council. (d) Articles of feather. The goods...

  8. The origin of the eukaryotic cell

    NASA Technical Reports Server (NTRS)

    Hartman, H.

    1984-01-01

    The endosymbiotic hypothesis for the origin of the eukaryotic cell has been applied to the origin of the mitochondria and chloroplasts. However as has been pointed out by Mereschowsky in 1905, it should also be applied to the nucleus as well. If the nucleus, mitochondria and chloroplasts are endosymbionts, then it is likely that the organism that did the engulfing was not a DNA-based organism. In fact, it is useful to postulate that this organism was a primitive RNA-based organism. This hypothesis would explain the preponderance of RNA viruses found in eukaryotic cells. The centriole and basal body do not have a double membrane or DNA. Like all MTOCs (microtubule organising centres), they have a structural or morphic RNA implicated in their formation. This would argue for their origin in the early RNA-based organism rather than in an endosymbiotic event involving bacteria. Finally, the eukaryotic cell uses RNA in ways quite unlike bacteria, thus pointing to a greater emphasis of RNA in both control and structure in the cell. The origin of the eukaryotic cell may tell us why it rather than its prokaryotic relative evolved into the metazoans who are reading this paper.

  9. Photosynthesis and the origin of life.

    PubMed

    Hartman, H

    1998-10-01

    The origin and evolution of photosynthesis is considered to be the key to the origin of life. This eliminates the need for a soup as the synthesis of the bioorganics are to come from the fixation of carbon dioxide and nitrogen. No soup then no RNA world or Protein world. Cyanobacteria have been formed by the horizontal transfer of green sulfur bacterial photoreaction center genes by means of a plasmid into a purple photosynthetic bacterium. The fixation of carbon dioxide is considered to have evolved from a reductive dicarboxylic acid cycle (Chloroflexus) which was then followed by a reductive tricarboxylic acid cycle (Chlorobium) and finally by the reductive pentose phosphate cycle (Calvin cycle). The origin of life is considered to have occurred in a hot spring on the outgassing early earth. The first organisms were self-replicating iron-rich clays which fixed carbon dioxide into oxalic and other dicarboxylic acids. This system of replicating clays and their metabolic phenotype then evolved into the sulfide rich region of the hotspring acquiring the ability to fix nitrogen. Finally phosphate was incorporated into the evolving system which allowed the synthesis of nucleotides and phospholipids. If biosynthesis recapitulates biopoesis, then the synthesis of amino acids preceded the synthesis of the purine and pyrimidine bases. Furthermore the polymerization of the amino acid thioesters into polypeptides preceded the directed polymerization of amino acid esters by polynucleotides. Thus the origin and evolution of the genetic code is a late development and records the takeover of the clay by RNA.

  10. Prevolutionary dynamics and the origin of evolution.

    PubMed

    Nowak, Martin A; Ohtsuki, Hisashi

    2008-09-30

    Life is that which replicates and evolves. The origin of life is also the origin of evolution. A fundamental question is when do chemical kinetics become evolutionary dynamics? Here, we formulate a general mathematical theory for the origin of evolution. All known life on earth is based on biological polymers, which act as information carriers and catalysts. Therefore, any theory for the origin of life must address the emergence of such a system. We describe prelife as an alphabet of active monomers that form random polymers. Prelife is a generative system that can produce information. Prevolutionary dynamics have selection and mutation, but no replication. Life marches in with the ability of replication: Polymers act as templates for their own reproduction. Prelife is a scaffold that builds life. Yet, there is competition between life and prelife. There is a phase transition: If the effective replication rate exceeds a critical value, then life outcompetes prelife. Replication is not a prerequisite for selection, but instead, there can be selection for replication. Mutation leads to an error threshold between life and prelife.

  11. A Dickensian origin for Sherrington's enchanted loom?

    PubMed

    O'Brien, J; Bracewell, R M

    2015-01-01

    Sherrington's image of the mind-brain as an 'enchanted loom' has intrigued scientists for decades. Its origin, however, has been unclear. Here, we make a new suggestion as to where it may have come from. The article sheds light on the connections between literary and scientific similes and metaphors.

  12. The Atomic Origin of the Reflection Law

    ERIC Educational Resources Information Center

    Prytz, Kjell

    2016-01-01

    It will be demonstrated how the reflection law may be derived on an atomic basis using the plane wave approximation together with Huygens' principle. The model utilized is based on the electric dipole character of matter originating from its molecular constituents. This approach is not new but has, since it was first introduced by Ewald and Oseen…

  13. Developmental origin of postnatal cardiomyogenic progenitor cells

    PubMed Central

    Liu, Yuan-Hung; Lai, Ling-Ping; Huang, Shih-Yun; Lin, Yi-Shuan; Wu, Shinn-Chih; Chou, Chih-Jen; Lin, Jiunn-Lee

    2016-01-01

    Aim: To trace the cell origin of the cells involved in postnatal cardiomyogenesis. Materials & methods: Nkx2.5 enhancer-eGFP (Nkx2.5 enh-eGFP) mice were used to test the cardiomyogenic potential of Nkx2.5 enhancer-expressing cells. By analyzing Cre excision of activated Nkx2.5-eGFP+ cells from different lineage-Cre/Nkx2.5 enh-eGFP/ROSA26 reporter mice, we traced the developmental origin of Nkx2.5 enhancer-expressing cells. Results: Nkx2.5 enhancer-expressing cells could differentiate into striated cardiomyocytes both in vitro and in vivo. Nkx2.5-eGFP+ cells increased remarkably after experimental myocardial infarction (MI). The post-MI Nkx2.5-eGFP+ cells originated from the embryonic epicardial cells, not from the pre-existing cardiomyocytes, endothelial cells, cardiac neural crest cells or perinatal/postnatal epicardial cells. Conclusion: Postnatal Nkx2.5 enhancer-expressing cells are cardiomyogenic progenitor cells and originate from embryonic epicardium-derived cells. PMID:28031967

  14. Prevolutionary dynamics and the origin of evolution

    PubMed Central

    Nowak, Martin A.; Ohtsuki, Hisashi

    2008-01-01

    Life is that which replicates and evolves. The origin of life is also the origin of evolution. A fundamental question is when do chemical kinetics become evolutionary dynamics? Here, we formulate a general mathematical theory for the origin of evolution. All known life on earth is based on biological polymers, which act as information carriers and catalysts. Therefore, any theory for the origin of life must address the emergence of such a system. We describe prelife as an alphabet of active monomers that form random polymers. Prelife is a generative system that can produce information. Prevolutionary dynamics have selection and mutation, but no replication. Life marches in with the ability of replication: Polymers act as templates for their own reproduction. Prelife is a scaffold that builds life. Yet, there is competition between life and prelife. There is a phase transition: If the effective replication rate exceeds a critical value, then life outcompetes prelife. Replication is not a prerequisite for selection, but instead, there can be selection for replication. Mutation leads to an error threshold between life and prelife. PMID:18791073

  15. Cosmic Origins Program Annual Technology Report

    NASA Technical Reports Server (NTRS)

    Pham, Bruce Thai; Neff, Susan Gale

    2015-01-01

    What is the Cosmic Origins (COR) Program? From ancient times, humans have looked up at the night sky and wondered: Are we alone? How did the universe come to be? How does the universe work? COR focuses on the second question. Scientists investigating this broad theme seek to understand the origin and evolution of the universe from the Big Bang to the present day, determining how the expanding universe grew into a grand cosmic web of dark matter enmeshed with galaxies and pristine gas, forming, merging, and evolving over time. COR also seeks to understand how stars and planets form from clouds in these galaxies to create the heavy elements that are essential to life starting with the first generation of stars to seed the universe, and continuing through the birth and eventual death of all subsequent generations of stars. The COR Programs purview includes the majority of the field known as astronomy, from antiquity to the present.

  16. Tektites and their origin. [properties and distribution

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.

    1975-01-01

    A study was conducted of the literature pertaining to the origin and characteristics of tektites. Topics discussed include tektite distribution in geographical locations, shapes of tektites, internal structure of tektites, physical properties, mechanical properties, optical properties, chemical composition, and comparisons with compositions of impact materials. Various arguments are presented on the terrestrial origin of tektites. It was found that some lunar craters of considerable size must be the products of volcanism which occurred during the past few million years, and that the moon must have within it a reservoir of rock which is considerably more like the mantle of the earth than like the rocks from which the basalts of the lunar crust are derived.

  17. Origin and variation of tunicate secondary metabolites.

    PubMed

    Schmidt, Eric W; Donia, Mohamed S; McIntosh, John A; Fricke, W Florian; Ravel, Jacques

    2012-02-24

    Ascidians (tunicates) are rich sources of structurally elegant, pharmaceutically potent secondary metabolites and, more recently, potential biofuels. It has been demonstrated that some of these compounds are made by symbiotic bacteria and not by the animals themselves, and for a few other compounds evidence exists supporting a symbiotic origin. In didemnid ascidians, compounds are highly variable even in apparently identical animals. Recently, we have explained this variation at the genomic and metagenomic levels and have applied the basic scientific findings to drug discovery and development. This review discusses what is currently known about the origin and variation of symbiotically derived metabolites in ascidians, focusing on the family Didemnidae, where most research has occurred. Applications of our basic studies are also described.

  18. The Origin of the Solar Wind

    NASA Astrophysics Data System (ADS)

    Woo, Richard; Habbal, Shadia Rifai

    2002-12-01

    Nearly 1,400 years ago, Chinese astronomers noticed that comet tails always point away from the Sun. They concluded that the Sun must have chi—a basic life force—that blows the tails away. It wasn't until the middle of the 20th century that scientists understood that this "force" actually consisted of little pieces of the sun itself—protons and electrons—blowing out into the solar system as a "wind" at more than a million kilometers per hour. The traditional view of the solar wind's origins suggests that it originates from special regions on the Sun, called coronal holes. Woo and Habbal present new evidence showing that the wind actually emanates from all regions on the Sun.

  19. Origin of the Autophagosomal Membrane in Plants

    PubMed Central

    Zhuang, Xiaohong; Chung, Kin Pan; Jiang, Liwen

    2016-01-01

    During autophagy, cargo molecules destined for degradation are sequestrated into a double-membrane structure called autophagosome, which subsequently fuses with the vacuole. An isolation membrane structure (also called the phagophore) initiates from the platform termed PAS (phagophore assembly site or preautophagosomal structure), which then elongates and expands to become the completed autophagosome. The origin of the membrane for autophagosome formation has been extensively investigated but remains an enigma in the field of autophagy. In yeast and mammalian cells multiple membrane sources have been suggested to contribute to autophagosome formation at different steps, from initiation through expansion and maturation. Recent studies in plants have provided a significant advance in our understanding of the conserved role of autophagy and the underlying mechanism for autophagosome formation. Here, we will discuss and evaluate these new findings on autophagosome formation in plants, with a particular focus on the origin of plant autophagosomal membranes. PMID:27867391

  20. Origin of flaw-tolerance in nacre

    PubMed Central

    Huang, Zaiwang; Li, Xiaodong

    2013-01-01

    Over the past decades, our understanding of nacre's toughening origin has long stayed at the level of crack deflection along the biopolymer interface between aragonite platelets. It has been widely thought that the ceramic aragonite platelets in nacre invariably remain shielded from the propagating crack. Here we report an unexpected experimental observation that the propagating crack, surprisingly, invades the aragonite platelet following a zigzag crack propagation trajectory. The toughening origin of previously-thought brittle aragonite platelet is ascribed to its unique nanoparticle-architecture, which tunes crack propagation inside the aragonite platelet in an intergranular manner. For comparison, we also investigated the crack behavior in geologic aragonite mineral (pure monocrystal) and found that the crack propagates in a cleavage fashion, in sharp contrast with the intergranular cracking in the aragonite platelet of nacre. These two fundamentally different cracking mechanisms uncover a new toughening strategy in nacre's hierarchical flaw-tolerance design. PMID:23603788

  1. The origin of OB runaway stars.

    PubMed

    Fujii, Michiko S; Portegies Zwart, Simon

    2011-12-09

    About 20% of all massive stars in the Milky Way have unusually high velocities, the origin of which has puzzled astronomers for half a century. We argue that these velocities originate from strong gravitational interactions between single stars and binaries in the centers of star clusters. The ejecting binary forms naturally during the collapse of a young (≤1 million years old) star cluster. This model replicates the key characteristics of OB runaways in our galaxy, and it explains the presence of runaway stars of ≥100 solar masses (M(⊙)) around young star clusters, such as R136 and Westerlund 2. The high proportion and the distributions in mass and velocity of runaways in the Milky Way are reproduced if the majority of massive stars are born in dense and relatively low-mass (5000 to 10,000 M(⊙)) clusters.

  2. Killing Me Softly: The Fetal Origins Hypothesis*

    PubMed Central

    Almond, Douglas

    2013-01-01

    In the epidemiological literature, the fetal origins hypothesis associated with David J. Barker posits that chronic, degenerative conditions of adult health, including heart disease and type 2 diabetes, may be triggered by circumstance decades earlier, in utero nutrition in particular. Economists have expanded on this hypothesis, investigating a broader range of fetal shocks and circumstances and have found a wealth of later-life impacts on outcomes including test scores, educational attainment, and income, along with health. In the process, they have provided some of the most credible observational evidence in support of the hypothesis. The magnitude of the impacts is generally large. Thus, the fetal origins hypothesis has not only survived contact with economics, but has flourished. PMID:25152565

  3. Origin of flaw-tolerance in nacre.

    PubMed

    Huang, Zaiwang; Li, Xiaodong

    2013-01-01

    Over the past decades, our understanding of nacre's toughening origin has long stayed at the level of crack deflection along the biopolymer interface between aragonite platelets. It has been widely thought that the ceramic aragonite platelets in nacre invariably remain shielded from the propagating crack. Here we report an unexpected experimental observation that the propagating crack, surprisingly, invades the aragonite platelet following a zigzag crack propagation trajectory. The toughening origin of previously-thought brittle aragonite platelet is ascribed to its unique nanoparticle-architecture, which tunes crack propagation inside the aragonite platelet in an intergranular manner. For comparison, we also investigated the crack behavior in geologic aragonite mineral (pure monocrystal) and found that the crack propagates in a cleavage fashion, in sharp contrast with the intergranular cracking in the aragonite platelet of nacre. These two fundamentally different cracking mechanisms uncover a new toughening strategy in nacre's hierarchical flaw-tolerance design.

  4. Origin of flaw-tolerance in nacre

    NASA Astrophysics Data System (ADS)

    Huang, Zaiwang; Li, Xiaodong

    2013-04-01

    Over the past decades, our understanding of nacre's toughening origin has long stayed at the level of crack deflection along the biopolymer interface between aragonite platelets. It has been widely thought that the ceramic aragonite platelets in nacre invariably remain shielded from the propagating crack. Here we report an unexpected experimental observation that the propagating crack, surprisingly, invades the aragonite platelet following a zigzag crack propagation trajectory. The toughening origin of previously-thought brittle aragonite platelet is ascribed to its unique nanoparticle-architecture, which tunes crack propagation inside the aragonite platelet in an intergranular manner. For comparison, we also investigated the crack behavior in geologic aragonite mineral (pure monocrystal) and found that the crack propagates in a cleavage fashion, in sharp contrast with the intergranular cracking in the aragonite platelet of nacre. These two fundamentally different cracking mechanisms uncover a new toughening strategy in nacre's hierarchical flaw-tolerance design.

  5. On the origins of psychoanalytic psychohistory.

    PubMed

    Pietikainen, Petteri; Ihanus, Juhani

    2003-05-01

    This article examines the origins and early development of psychoanalytically inspired psychohistory from the late 1950s to the early 1970s. It focuses on Erik H. Erikson, Bruce Mazlish, and Robert Jay Lifton and illustrates their contributions to psychoanalytic psychohistory. Erikson, Mazlish, and Lifton were core members of the Wellfleet group, a research project originally funded by the American Academy of Arts and Sciences in 1965 to conceptualize the foundation of psychohistory. The article gives an account of the early history of the Wellfleet group and argues for specific historical reasons to explain why psychoanalytic psychohistory emerged on the East Coast of the United States in the late 1950s and early 1960s. A critique of the Wellfleet group in unpublished correspondence of Erich Fromm and David Riesman is also discussed.

  6. Cholangiocarcinomas can originate from hepatocytes in mice

    PubMed Central

    Fan, Biao; Malato, Yann; Calvisi, Diego F.; Naqvi, Syed; Razumilava, Nataliya; Ribback, Silvia; Gores, Gregory J.; Dombrowski, Frank; Evert, Matthias; Chen, Xin; Willenbring, Holger

    2012-01-01

    Intrahepatic cholangiocarcinomas (ICCs) are primary liver tumors with a poor prognosis. The development of effective therapies has been hampered by a limited understanding of the biology of ICCs. Although ICCs exhibit heterogeneity in location, histology, and marker expression, they are currently thought to derive invariably from the cells lining the bile ducts, biliary epithelial cells (BECs), or liver progenitor cells (LPCs). Despite lack of experimental evidence establishing BECs or LPCs as the origin of ICCs, other liver cell types have not been considered. Here we show that ICCs can originate from fully differentiated hepatocytes. Using a mouse model of hepatocyte fate tracing, we found that activated NOTCH and AKT signaling cooperate to convert normal hepatocytes into biliary cells that act as precursors of rapidly progressing, lethal ICCs. Our findings suggest a previously overlooked mechanism of human ICC formation that may be targetable for anti-ICC therapy. PMID:22797301

  7. Nepalese origin of cholera epidemic in Haiti.

    PubMed

    Frerichs, R R; Keim, P S; Barrais, R; Piarroux, R

    2012-06-01

    Cholera appeared in Haiti in October 2010 for the first time in recorded history. The causative agent was quickly identified by the Haitian National Public Health Laboratory and the United States Centers for Disease Control and Prevention as Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Since then, >500 000 government-acknowledged cholera cases and >7000 deaths have occurred, the largest cholera epidemic in the world, with the real death toll probably much higher. Questions of origin have been widely debated with some attributing the onset of the epidemic to climatic factors and others to human transmission. None of the evidence on origin supports climatic factors. Instead, recent epidemiological and molecular-genetic evidence point to the United Nations peacekeeping troops from Nepal as the source of cholera to Haiti, following their troop rotation in early October 2010. Such findings have important policy implications for shaping future international relief efforts.

  8. Charles Darwin and the origin of life.

    PubMed

    Peretó, Juli; Bada, Jeffrey L; Lazcano, Antonio

    2009-10-01

    When Charles Darwin published The Origin of Species 150 years ago he consciously avoided discussing the origin of life. However, analysis of some other texts written by Darwin, and of the correspondence he exchanged with friends and colleagues demonstrates that he took for granted the possibility of a natural emergence of the first life forms. As shown by notes from the pages he excised from his private notebooks, as early as 1837 Darwin was convinced that "the intimate relation of Life with laws of chemical combination, & the universality of latter render spontaneous generation not improbable". Like many of his contemporaries, Darwin rejected the idea that putrefaction of preexisting organic compounds could lead to the appearance of organisms. Although he favored the possibility that life could appear by natural processes from simple inorganic compounds, his reluctance to discuss the issue resulted from his recognition that at the time it was possible to undertake the experimental study of the emergence of life.

  9. Origins and evolution of eukaryotic RNA interference

    PubMed Central

    Shabalina, Svetlana A.; Koonin, Eugene V.

    2009-01-01

    Small interfering RNAs (siRNAs) and genome-encoded microRNAs (miRNAs) silence genes via complementary interactions with mRNAs. With thousands of miRNA genes identified and genome sequences of diverse eukaryotes available for comparison, the opportunity emerges for insights into origin and evolution of RNA interference (RNAi). The miRNA repertoires of plants and animals appear to have evolved independently. However, conservation of the key proteins involved in RNAi suggests that the last common ancestor of modern eukaryotes possessed siRNA-based mechanisms. Prokaryotes have a RNAi-like defense system that is functionally analogous but not homologous to eukaryotic RNAi. The protein machinery of eukaryotic RNAi seems to have been pieced together from ancestral proteins of archaeal, bacterial and phage origins that are involved in DNA repair and RNA-processing pathways. PMID:18715673

  10. Origin of Mass Hierarchies in Gauge Theories

    NASA Astrophysics Data System (ADS)

    Cvetic, Mirjam

    We study the origin of mass hierarchies for different systems of fundamental interactions; in particular, we analyze whether the W(,L)-W(,R) mass splitting, and the fermion mass hierarchy can be of radiative origin. Within the left-right symmetric gauge structure G (TBOND) SU(2)(,L) x SU(2)(,R) x U(1)(,B-L), where fermions remain massless, the W(,L)-W(,R) mass splitting can be of radiative origin with (eta) = M(,W(,R))/m(,W(,L))) < 2 to 4. This result evades the Georgi-Pais constraint, which claims that quantum corrections can not change the symmetry of the vacuum solution at the tree level. It is found that for a realistic model, where fermions acquire mass, quantum corrections do not, however, restrict (eta) anymore. When the constraints of N = 1 supergravity are imposed on the gauge structure G with the minimal set of Higgs fields, one arrives at the following results: (i) the gravitino mass, is the only relevant scale of the model, it sets the scale for the mass of W(,R), (ii) the mass of W(,L) is necessarily derived radiatively, and (iii) (eta) = (m(,W(,R))/m(,W(,L))) < 0 (16(pi)('2)/g('2))(' 1/4) = 0(10). When the parity-odd singlet is added, a maxi-hierarchy with n >> 1 is a permissible solution. The origin of interfamily mass hierarchy (m(,(tau)) >> m(,(mu)) >> m(,e)) is studied in an instructive model where the three families and the corresponding Higgs fields appear symmetrically in the original Lagrangian. The desired interfamily hierarchy can have radiative origin. This approach again evades the Georgi-Pais constraint. The model suffers from the problem of light pseudo-Goldstone particles. In an attempt to study a complete fermion mass hierarchy problem we study the fermionic mass matrix within a realistic preonic model with four (e, (mu),(tau), (tau)') -fermionic families. The fermion mass hierarchy is realized as a hierarchy in sizes between (e,(mu))- and ((tau),(tau)') -families and as a hierarchy between the condensates formed out of preonic

  11. Common origin of visible and dark universe

    SciTech Connect

    Gu Peihong; Sarkar, Utpal

    2010-02-01

    Dark matter, baryonic matter, and dark energy have different properties but contribute comparable energy density to the present Universe. We point out that they may have a common origin. As the dark energy has a scale far lower than all known scales in particle physics but very close to neutrino masses, while the excess matter over antimatter in the baryonic sector is probably related to the neutrino-mass generation, we unify the origin of the dark and visible universe in a variant of the seesaw model. In our model (i) the dark matter relic density is a dark matter asymmetry emerged simultaneously with the baryon asymmetry from leptogenesis; (ii) the dark energy is due to a pseudo-Nambu-Goldstone-Boson associated with the neutrino-mass generation.

  12. The potential origin of glioblastoma initiating cells

    PubMed Central

    Chesler, David A.; Berger, Mitchell S.; Quinones-Hinojosa, Alfredo

    2013-01-01

    Despite intensive clinical and laboratory research and effort, Glioblastoma remains the most common and invariably lethal primary cancer of the central nervous system. The identification of stem cell and lineage-restricted progenitor cell populations within the adult human brain in conjunction with the discovery of stem-like cells derived from gliomas which are themselves tumorigenic and have been shown to have properties of self-renewal and multipotency, has led to the hypothesis that this population of cells may represent glioma initiating cells. Extensive research characterizing the anatomic distribution and phenotype of neural stem cells in the adult brain, and the genetic underpinnings needed for malignant transformation may ultimately lead to the identification of the cellular origin for glioblastoma. Defining the cellular origin of this lethal disease may ultimately provide new therapeutic targets and modalities finally altering an otherwise bleak outcome for patients with glioblastoma. PMID:22202053

  13. Origin of the earth's ocean basins

    NASA Technical Reports Server (NTRS)

    Frey, H.

    1977-01-01

    The earth's original ocean basins are proposed to be mare-type basins produced 4 billion y.a. by the flux of asteroid-sized objects responsible for the lunar mare basins. Scaling upward from the observed number of lunar basins for the greater capture cross-section and impact velocity of the earth indicates that at least 50% of an original global crust would have been converted to basin topography. These basins were flooded by basaltic liquids in times short compared to the isostatic adjustment time for the basin. The modern crustal dichotomy (60% oceanic, 40% continental crust) was established early in the history of the earth, making possible the later onset of plate tectonic processes. These later processes have subsequently reworked, in several cycles, principally the oceanic parts of the earth's crust, changing the configuration of the continents in the process. Ocean basins (and oceans themselves) may be rare occurrences on planets in other star systems.

  14. The burrowing origin of modern snakes

    PubMed Central

    Yi, Hongyu; Norell, Mark A.

    2015-01-01

    Modern snakes probably originated as habitat specialists, but it controversial unclear whether they were ancestrally terrestrial burrowers or marine swimmers. We used x-ray virtual models of the inner ear to predict the habit of Dinilysia patagonica, a stem snake closely related to the origin of modern snakes. Previous work has shown that modern snakes perceive substrate vibrations via their inner ear. Our data show that D. patagonica and modern burrowing squamates share a unique spherical vestibule in the inner ear, as compared with swimmers and habitat generalists. We built predictive models for snake habit based on their vestibular shape, which estimated D. patagonica and the hypothetical ancestor of crown snakes as burrowers with high probabilities. This study provides an extensive comparative data set to test fossoriality quantitatively in stem snakes, and it shows that burrowing was predominant in the lineages leading to modern crown snakes. PMID:26702436

  15. Origin of the earth's ocean basins

    NASA Technical Reports Server (NTRS)

    Frex, H.

    1977-01-01

    The earth's original ocean basins were mare-type basins produced 4 billion years ago by the flux of asteroid-sized objects responsible for the lunar mare basins. Scaling upwards from the observed number of lunar basins for the greater capture cross-section and impact velocity of the Earth indicates that at least 50 percent of an original global crust would have been converted to basin topography. These basins were flooded by basaltic liquids in times short compared to the isostatic adjustment time for the basin. The modern crustal dichotomy (60 percent oceanic, 40 percent continental crust) was established early in the history of the earth, making possible the later onset of plate tectonic processes. These later processes have subsequently reworked, in several cycles, principally the oceanic parts of the earth's crust, changing the configuration of the continents in the process. Ocean basins (and oceans themselves) may be rare occurrences on planets in other star systems.

  16. Open Questions on the Origin of Eukaryotes.

    PubMed

    López-García, Purificación; Moreira, David

    2015-11-01

    Despite recent progress, the origin of the eukaryotic cell remains enigmatic. It is now known that the last eukaryotic common ancestor was complex and that endosymbiosis played a crucial role in eukaryogenesis at least via the acquisition of the alphaproteobacterial ancestor of mitochondria. However, the nature of the mitochondrial host is controversial, although the recent discovery of an archaeal lineage phylogenetically close to eukaryotes reinforces models proposing archaea-derived hosts. We argue that, in addition to improved phylogenomic analyses with more comprehensive taxon sampling to pinpoint the closest prokaryotic relatives of eukaryotes, determining plausible mechanisms and selective forces at the origin of key eukaryotic features, such as the nucleus or the bacterial-like eukaryotic membrane system, is essential to constrain existing models.

  17. Mapping origins of DNA replication in eukaryotes.

    PubMed

    Gerbi, Susan A

    2005-01-01

    Methods are described here to map an origin of replication in eukaryotes. Replicating DNA is enriched by BND cellulose column chromatography and by lambda-exonuclease digestion; this approach has largely superceded enrichment by BrdU incorporation. The general area in which replication begins can be deciphered by neutral/neutral 2D gel electrophoresis: a restriction fragment containing the replication bubble will form a bubble arc on these gels. A more sensitive method employs PCR analysis of nascent strands that are size-fractionated. Once the general area containing the origin of bidirectional replication has been mapped, a finer level of resolution can be obtained by replication initiation point (RIP) mapping, in which start sites of DNA synthesis are identified at the nucleotide level.

  18. Fetal origins of the metabolic syndrome.

    PubMed

    Xita, Nektaria; Tsatsoulis, Agathocles

    2010-09-01

    The natural history of metabolic syndrome and polycystic ovary syndrome (PCOS), which shares many components of metabolic syndrome, may originate in intrauterine life. Evidence from epidemiological observations, clinical, and experimental animal studies suggest that the nutritional, hormonal, and metabolic environment afforded by the mother may permanently program differentiating target tissues of the offspring toward the development of metabolic syndrome/PCOS phenotype in adult life. The mechanisms of fetal programming are not well understood. Thus, the altered tissue differentiation may be the result of fetal adaptive responses representing homeostatic adaptations due to alterations in fetal nutrition. Also, tissues under the influence of androgen excess may be directed toward a more masculine phenotype with regard to reproductive, neuroendocrine, and metabolic traits, while the importance of epigenetics in fetal origin of metabolic syndrome/PCOS cannot be overlooked.

  19. The origins of Ptolemy's astronomical tables.

    NASA Astrophysics Data System (ADS)

    Newton, R. R.

    Following the line set by his earlier book 'The crime of Claudius Ptolemy' the author discusses here the numerous astronomical tables in Ptolemy's work that have been calculated with the aid of trigonometric tables, as well as a few that are nonlinear but that do not involve trigonometry. The purpose in this study is to determine, if possible, whether Ptolemy calculated these tables or whether he copied them from now-lost original works. The conclusion isthat Ptolemy made few if any original contributions to astronomy, either observational or computational.Contents: 1. Introduction; thetable of chords. 2. The tables of the latitude and of gnomon shadows.3. Tables of the Sun. 4. Astronomical geography. 5. The tables of theMoon. 6. Eclipse tables. 7. Tables of the planets. 8. The empirical basis for Hipparchus's mean motions of the Moon. 9. Summary and conclusions.

  20. Solar wind origin in coronal funnels.

    PubMed

    Tu, Chuan-Yi; Zhou, Cheng; Marsch, Eckart; Xia, Li-Dong; Zhao, Liang; Wang, Jing-Xiu; Wilhelm, Klaus

    2005-04-22

    The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by various ions with the force-free magnetic field as extrapolated from photospheric magnetograms to different altitudes. Specifically, we find that Ne7+ ions mostly radiate around 20 megameters, where they have outflow speeds of about 10 kilometers per second, whereas C3+ ions with no average flow speed mainly radiate around 5 megameters. Based on these results, a model for understanding the solar wind origin is suggested.

  1. The binary fission origin of the moon

    NASA Technical Reports Server (NTRS)

    Binder, Alan B.

    1986-01-01

    The major arguments for and against the binary fission model of lunar origin are reviewed. Unresolved problems include: (1) how the protoearth acquired sufficient angular velocity to fission, and (2) how the earth-moon system lost its excess angular momentum after fission. Despite these uncertainties, the compositional similarities between the earth's mantle and the bulk moon suggest that the fission model is worth considering. The proposed sequence of events in the formation of the moon by binary fission is given.

  2. The origin of Sarcoptes scabiei in wombats.

    PubMed

    Morrison, David A; Ljunggren, Erland L; Mattsson, Jens G

    2003-12-01

    In 2002, Skerratt et al. phylogenetically analysed sequence data for several haplotypes of the parasitic mite Sarcoptes scabiei from wombat, human and dog hosts in Australia, to test scenarios concerning the origin and diversification of the scabies infections in wombats. Here we note that their substantive conclusions can be called into question by the choice of model used in their phylogenetic analysis, the lack of a root for their phylogenetic trees, and their interpretation of the evolutionary scenario.

  3. The origin of the planetesimal theory.

    PubMed

    Brush, S G

    1977-04-01

    T. C. Chamberlin suggested in 1897, on the basis of geological and climatological arguments, that the planets were formed by accretion of cold solid partices. With F. R. Moulton he developed convincing arguments against the Laplace nebular hypothesis and published a comprehensive 'planetesimal theory' of the origin of the solar system in 1905. The Chamberlin-Moulton theory has current as well as historical interest.

  4. [Original contributions of Latin Americans to anesthesiology].

    PubMed

    Aldrete, J A

    1998-10-01

    The original contributions of Latin American physicians to the science of anesthesiology are described. Many contributions have been unfairly ignored mainly because they were never published in English, but others have likewise been passed over even when published in the most prestigious journals in the field. Although many discoveries by Latin Americans have been made in the area of regional anesthesia, a considerable number of contributions have involved other aspects of anesthesia as well.

  5. The origin and evolution of model organisms

    NASA Technical Reports Server (NTRS)

    Hedges, S. Blair

    2002-01-01

    The phylogeny and timescale of life are becoming better understood as the analysis of genomic data from model organisms continues to grow. As a result, discoveries are being made about the early history of life and the origin and development of complex multicellular life. This emerging comparative framework and the emphasis on historical patterns is helping to bridge barriers among organism-based research communities.

  6. Infectious causes of fever of unknown origin.

    PubMed

    McGregor, Alastair C; Moore, David A

    2015-06-01

    The causes of fever of unknown origin (FUO) are changing because advances in clinical practice and diagnostics have facilitated the identification of some infections. A variety of bacterial infections can cause FUO, and these can be divided into those that are easy to identify using culture and those that require serological or molecular tests for identification. A number of viral, parasitic and fungal infections can also cause prolonged fever. This article summarises the clinical features and diagnostic strategy of these infections.

  7. Planets and their atmospheres - Origin and evolution

    NASA Astrophysics Data System (ADS)

    Lewis, J. S.; Prinn, R. G.

    The origin, evolution, and composition of the planetary atmospheres are examined in an introductory review of ground-based and in situ observations and theoretical models. Chapters are devoted to the retention of volatiles by planets; evolutionary processes (such as hydrogen loss, accretion and outgassing, dissolution, photo-condensation, reactions with planetary surfaces, biochemical transformations, and atmospheric escape); and the present characteristics of the planetary, lunar-size-object, and asteroid atmospheres. Graphs, diagrams, and tables of numerical data are provided.

  8. Eukaryotic evolution: early origin of canonical introns.

    PubMed

    Simpson, Alastair G B; MacQuarrie, Erin K; Roger, Andrew J

    2002-09-19

    Spliceosomal introns, one of the hallmarks of eukaryotic genomes, were thought to have originated late in evolution and were assumed not to exist in eukaryotes that diverged early -- until the discovery of a single intron with an aberrant splice boundary in the primitive 'protozoan' Giardia. Here we describe introns from a close relative of Giardia, Carpediemonas membranifera, that have boundary sequences of the normal eukaryotic type, indicating that canonical introns are likely to have arisen very early in eukaryotic evolution.

  9. The puzzling origin of the genetic code.

    PubMed

    Cedergren, R; Miramontes, P

    1996-06-01

    Recent results add to the mystery of the origin of the genetic code. In spite of early doubts, RNA can discriminate between hydrophobic amino acids under certain contexts. Moreover, codon reassignment, which has taken place in several organisms and mitochondria, is not a random process. Finally, phylogenies of some aminoacyl-tRNA synthetases suggest that the entire code was not completely assigned at the time of the divergence of bacteria from nucleated cells.

  10. Research into the origins of engineering thermodynamics

    SciTech Connect

    Bejan, A.

    1988-09-01

    This paper draws attention to a series of misconceptions and misstatements regarding the origin and meaning of some of the most basic concepts of engineering thermodynamics. The six examples exhibited in the paper relate to the concepts of reversibility, entropy, mechanical equivalent of the calorie, the first law of thermodynamics for open systems, enthalpy and the Diesel cycle. A complete list of the pioneering references concludes the paper.

  11. Origins of the Kuroshio and Mindanao Current

    DTIC Science & Technology

    2014-09-30

    transfer of energy from the eddies to the mean flow in the KC and MC origin regions. Modeling The MITgcm 4D-Var state estimation using satellite SSH ...significantly reduced to increase the model performance near the end of the hindcast periods. Maps of SSH prediction error for different forecast...periods have been constructed and show that the state estimate improves the forecasts of SSH near the Philippine coast, where it is expected to

  12. Origins: an outreach project towards children

    NASA Astrophysics Data System (ADS)

    Moutou, C.

    2010-12-01

    We have developed and realised an outreach project about Origins, from the universe formation to the present epoch, in the context of the International Year of Astronomy. The aimed public is primary school, from 8 years age. Various media have been used, from the creation of a theater play to a pedagogical exhibition. The project was shown as a whole ten times during 2009, and the pedagogical elements are still used for school events.

  13. Life Origination Hydrate Hypothesis (LOH-Hypothesis)

    PubMed Central

    Ostrovskii, Victor; Kadyshevich, Elena

    2012-01-01

    The paper develops the Life Origination Hydrate Hypothesis (LOH-hypothesis), according to which living-matter simplest elements (LMSEs, which are N-bases, riboses, nucleosides, nucleotides), DNA- and RNA-like molecules, amino-acids, and proto-cells repeatedly originated on the basis of thermodynamically controlled, natural, and inevitable processes governed by universal physical and chemical laws from CH4, niters, and phosphates under the Earth's surface or seabed within the crystal cavities of the honeycomb methane-hydrate structure at low temperatures; the chemical processes passed slowly through all successive chemical steps in the direction that is determined by a gradual decrease in the Gibbs free energy of reacting systems. The hypothesis formulation method is based on the thermodynamic directedness of natural movement and consists ofan attempt to mentally backtrack on the progression of nature and thus reveal principal milestones alongits route. The changes in Gibbs free energy are estimated for different steps of the living-matter origination process; special attention is paid to the processes of proto-cell formation. Just the occurrence of the gas-hydrate periodic honeycomb matrix filled with LMSEs almost completely in its final state accounts for size limitation in the DNA functional groups and the nonrandom location of N-bases in the DNA chains. The slowness of the low-temperature chemical transformations and their “thermodynamic front” guide the gross process of living matter origination and its successive steps. It is shown that the hypothesis is thermodynamically justified and testable and that many observed natural phenomena count in its favor. PMID:25382120

  14. Feline Origin of Rotavirus Strain, Tunisia, 2008

    PubMed Central

    Fredj, Mouna Ben Hadj; Heylen, Elisabeth; Zeller, Mark; Fodha, Imene; Benhamida-Rebai, Meriam; Van Ranst, Marc; Matthijnssens, Jelle

    2013-01-01

    In Tunisia in 2008, an unusual G6P[9] rotavirus, RVA/human-wt/TUN/17237/2008/G6P[9], rarely found in humans, was detected in a child. To determine the origin of this strain, we conducted phylogenetic analyses and found a unique genotype constellation resembling rotaviruses belonging to the feline BA222-like genotype constellation. The strain probably resulted from direct cat-to-human transmission. PMID:23631866

  15. Original data preprocessor for Femap/Nastran

    NASA Astrophysics Data System (ADS)

    Oanta, Emil M.; Panait, Cornel; Raicu, Alexandra

    2016-12-01

    Automatic data processing and visualization in the finite elements analysis of the structural problems is a long run concern in mechanical engineering. The paper presents the `common database' concept according to which the same information may be accessed from an analytical model, as well as from a numerical one. In this way, input data expressed as comma-separated-value (CSV) files are loaded into the Femap/Nastran environment using original API codes, being automatically generated: the geometry of the model, the loads and the constraints. The original API computer codes are general, being possible to generate the input data of any model. In the next stages, the user may create the discretization of the model, set the boundary conditions and perform a given analysis. If additional accuracy is needed, the analyst may delete the previous discretizations and using the same information automatically loaded, other discretizations and analyses may be done. Moreover, if new more accurate information regarding the loads or constraints is acquired, they may be modelled and then implemented in the data generating program which creates the `common database'. This means that new more accurate models may be easily generated. Other facility consists of the opportunity to control the CSV input files, several loading scenarios being possible to be generated in Femap/Nastran. In this way, using original intelligent API instruments the analyst is focused to accurately model the phenomena and on creative aspects, the repetitive and time-consuming activities being performed by the original computer-based instruments. Using this data processing technique we apply to the best Asimov's principle `minimum change required / maximum desired response'.

  16. Origins Space Telescope: Solar System Science

    NASA Astrophysics Data System (ADS)

    Wright, Edward L.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its imagers and spectrographs will enable a variety of surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu.In the Solar System, OST will provide km/sec resolution on lines from planet, moons and comets. OST will measure molecular abundances and isotope ratios in planets and comets. OST will be able to do continuum surveys for faint moving sources such as Kuiper Belt Objects, enabling a census of smaller objects in the Kuiper Belt. If the putative Planet IX is massive enough to be self-luminous, then OST will be able to detect it out to thousands of AU from the Sun.

  17. Asynchronous origins of ectomycorrhizal clades of Agaricales.

    PubMed

    Ryberg, Martin; Matheny, P Brandon

    2012-05-22

    The ectomycorrhizal (ECM) symbiosis is the most widespread biotrophic nutritional mode in mushroom-forming fungi. ECM fungi include, though are not limited to, about 5000 described species of Agaricales from numerous, independently evolved lineages. Two central hypotheses suggest different explanations for the origin of ECM fungal diversity: (i) dual origins, initially with the Pinaceae in the Jurassic and later with angiosperms during the Late Cretaceous, and (ii) a simultaneous and convergent radiation of ECM lineages in response to cooling climate during the Palaeogene and advancing temperate ECM plant communities. Neither of these hypotheses is supported here. While we demonstrate support for asynchronous origins of ECM Agaricales, the timing of such events appears to have occurred more recently than suggested by the first hypothesis, first during the Cretaceous and later during the Palaeogene. We are also unable to reject models of rate constancy, which suggests that the diversity of ECM Agaricales is not a consequence of convergent rapid radiations following evolutionary transitions from saprotrophic to ECM habits. ECM lineages of Agaricales differ not only in age, but also in rates of diversification and rate of substitution at nuclear ribosomal RNA loci. These results question the biological uniformity of the ECM guild.

  18. Topological Origins of the Slow Solar Wind

    NASA Astrophysics Data System (ADS)

    Antiochos, S.

    2008-12-01

    Although the slow solar wind has been studied for decades with both in situ and remote sensing observations, its origin is still a matter of intense debate. In the standard quasi-steady model, the slow wind is postulated to originate near coronal hole boundaries that define topologically well-behaved separatrices between open and closed field regions. In the interchange model, on the other hand, the slow wind is postulated to originate on open flux that is dynamically diffusing throughout the seemingly closed-field corona. We argue in favor of the quasi-steady scenario and propose that the slow wind is due to two effects: First, the open-closed boundary is highly complex due to the complexity of the photospheric flux distribution. Second, this boundary is continuously driven by the transport of magnetic helicity from the closed field region into the open. The implications of this model for the structure and dynamics of the corona and slow wind are discussed, and observational tests of the model are presented. This work has been supported, in part, by the NASA LWS, HTP, and SR&T programs.

  19. West Florida shelf upwelling: Origins and pathways

    NASA Astrophysics Data System (ADS)

    Weisberg, Robert H.; Zheng, Lianyuan; Liu, Yonggang

    2016-08-01

    Often described as oligotrophic, the west Florida continental shelf supports abundant fisheries, experiences blooms of the harmful alga, Karenia brevis, and exhibits subsurface chlorophyll maxima evident in shipboard and glider surveys. Renewal of inorganic nutrients by the upwelling of deeper ocean water onto the shelf may account for this, but what are the origins and pathways by which such new water may broach the shelf break and advance toward the shoreline? We address these questions via numerical model simulations of pseudo-Lagrangian, isopycnic water parcel trajectories. Focus is on 2010, when the west Florida shelf was subjected to an anomalously protracted period of upwelling caused by Gulf of Mexico Loop Current interactions with the shelf slope. Origins and pathways are determined by integrating trajectories over successive 45 day intervals, beginning from different locations along the shelf break and at various locations and depths along the shelf slope. Waters upwelling across the shelf break are found to originate from relatively shallow depths along the shelf slope. Even for the anomalous 2010 year, much of this upwelling occurs from about 150 m and above, although waters may broach the shelf break from 300 m depth, particularly in the Florida Panhandle. Such interannual renewal of west Florida shelf waters appears to have profound effects on west Florida shelf ecology.

  20. The original colours of fossil beetles.

    PubMed

    McNamara, Maria E; Briggs, Derek E G; Orr, Patrick J; Noh, Heeso; Cao, Hui

    2012-03-22

    Structural colours, the most intense, reflective and pure colours in nature, are generated when light is scattered by complex nanostructures. Metallic structural colours are widespread among modern insects and can be preserved in their fossil counterparts, but it is unclear whether the colours have been altered during fossilization, and whether the absence of colours is always real. To resolve these issues, we investigated fossil beetles from five Cenozoic biotas. Metallic colours in these specimens are generated by an epicuticular multi-layer reflector; the fidelity of its preservation correlates with that of other key cuticular ultrastructures. Where these other ultrastructures are well preserved in non-metallic fossil specimens, we can infer that the original cuticle lacked a multi-layer reflector; its absence in the fossil is not a preservational artefact. Reconstructions of the original colours of the fossils based on the structure of the multi-layer reflector show that the preserved colours are offset systematically to longer wavelengths; this probably reflects alteration of the refractive index of the epicuticle during fossilization. These findings will allow the former presence, and original hue, of metallic structural colours to be identified in diverse fossil insects, thus providing critical evidence of the evolution of structural colour in this group.

  1. A Strategy for Origins of Life Research

    PubMed Central

    Scharf, Caleb; Virgo, Nathaniel; Aono, Masashi; Aubert-Kato, Nathanael; Aydinoglu, Arsev; Barahona, Ana; Barge, Laura M.; Benner, Steven A.; Biehl, Martin; Brasser, Ramon; Butch, Christopher J.; Chandru, Kuhan; Cronin, Leroy; Danielache, Sebastian; Fischer, Jakob; Hernlund, John; Hut, Piet; Ikegami, Takashi; Kimura, Jun; Kobayashi, Kensei; Mariscal, Carlos; McGlynn, Shawn; Menard, Brice; Packard, Norman; Pascal, Robert; Pereto, Juli; Rajamani, Sudha; Sinapayen, Lana; Smith, Eric; Switzer, Christopher; Takai, Ken; Tian, Feng; Ueno, Yuichiro; Voytek, Mary; Witkowski, Olaf; Yabuta, Hikaru

    2015-01-01

    Contents 1. Introduction 1.1. A workshop and this document 1.2. Framing origins of life science 1.2.1. What do we mean by the origins of life (OoL)? 1.2.2. Defining life 1.2.3. How should we characterize approaches to OoL science? 1.2.4. One path to life or many? 2. A Strategy for Origins of Life Research 2.1. Outcomes—key questions and investigations 2.1.1. Domain 1: Theory 2.1.2. Domain 2: Practice 2.1.3. Domain 3: Process 2.1.4. Domain 4: Future studies 2.2. EON Roadmap 2.3. Relationship to NASA Astrobiology Roadmap and Strategy documents and the European AstRoMap  Appendix I  Appendix II  Supplementary Materials  References PMID:26684503

  2. Planetary Systems and the Origins of Life

    NASA Astrophysics Data System (ADS)

    Pudritz, Ralph; Higgs, Paul; Stone, Jonathon

    2013-01-01

    Preface; Part I. Planetary Systems and the Origins of Life: 1. Observations of extrasolar planetary systems Shay Zucker; 2. The atmospheres of extrasolar planets L. Jeremy Richardson and Sara Seager; 3. Terrestrial planet formation Edward Thommes; 4. Protoplanetary disks, amino acids and the genetic code Paul Higgs and Ralph Pudritz; 5. Emergent phenomena in biology: the origin of cellular life David Deamer; Part II. Life on Earth: 6. Extremophiles: defining the envelope for the search for life in the Universe Lynn Rothschild; 7. Hyperthermophilic life on Earth - and on Mars? Karl Stetter; 8. Phylogenomics: how far back in the past can we go? Henner Brinkmann, Denis Baurain and Hervé Philippe; 9. Horizontal gene transfer, gene histories and the root of the tree of life Olga Zhaxybayeva and J. Peter Gogarten; 10. Evolutionary innovation versus ecological incumbency Adolf Seilacher; 11. Gradual origins for the Metazoans Alexandra Pontefract and Jonathan Stone; Part III. Life in the Solar System?: 12. The search for life on Mars Chris McKay; 13. Life in the dark dune spots of Mars: a testable hypothesis Eörs Szathmary, Tibor Ganti, Tamas Pocs, Andras Horvath, Akos Kereszturi, Szaniszlo Berzci and Andras Sik; 14. Titan: a new astrobiological vision from the Cassini-Huygens data François Raulin; 15. Europa, the Ocean Moon: tides, permeable ice, and life Richard Greenberg; Index.

  3. On the origin of Earth's Moon

    NASA Astrophysics Data System (ADS)

    Barr, Amy C.

    2016-09-01

    The Giant Impact is currently accepted as the leading theory for the formation of Earth's Moon. Successful scenarios for lunar origin should be able to explain the chemical composition of the Moon (volatile content and stable isotope ratios), the Moon's initial thermal state, and the system's bulk physical and dynamical properties. Hydrocode simulations of the impact have long been able to match the bulk properties, but recent, more detailed work on the evolution of the protolunar disk has yielded great insight into the origin of the Moon's chemistry and its early thermal history. Here I show that the community has constructed the elements of an end-to-end theory for lunar origin that matches the overwhelming majority of observational constraints. In spite of the great progress made in recent years, new samples of the Moon, clarification of processes in the impact-generated disk, and a broader exploration of impact parameter space could yield even more insights into this fundamental and uniquely challenging geophysical problem.

  4. The True Origin of Hypervelocity Stars

    NASA Astrophysics Data System (ADS)

    Gnedin, Oleg

    2011-10-01

    We propose to obtain WFC3 images of 4 hypervelocity stars in the Galactic halo, in order to conclusively establish their origin. This will be a final epoch of a long-term program to measure precise proper motions in an absolute inertial frame. The origin of these unique stars with extremely large positive radial velocities, in excess of the escape speed from the Galaxy, is consistent only with being ejected by the massive black hole at the Galactic center. Reconstructing the full three-dimensional space motion of these stars, through astrometric proper motions, provides a unique opportunity to measure the shape of the triaxial dark matter halo, at larger distances than is afforded by tidal streams. In Cycles 15 and 17 our team obtained two epochs of observations for these stars with ACS. The accuracy of the proper motion measurement was affected by the CTE degradation in ACS and the unexpected change in the PSF after SM4. The CTE error of HVS3 was unfortunately amplified by the need to use different guide stars and take the second-epoch observations at a 180 degree different orientation. We request third-epoch observations for 4 targets with WFC3 to double the proper motion baseline to 5-6 years and to reduce the systematic error using our newly-developed CTE correction. The new measurement will conclusively confirm or reject the Galactocentric origin of HVSs.

  5. Topological Origins of the Slow Solar Wind

    NASA Technical Reports Server (NTRS)

    Antiochos, Spiro

    2008-01-01

    Although the slow solar wind has been studied for decades with both in situ and remote sensing observations, its origin is still a matter of intense debate. In the standard quasi-steady model, the slow wind is postulated to originate near coronal hole boundaries that define topologically well-behaved separatrices between open and closed field regions. In the interchange model, on the other hand, the slow wind is postulated to originate on open flux that is dynamically diffusing throughout the seemingly closed-field corona. We argue in favor of the quasi-steady scenario and propose that the slow wind is due to two effects: First, the open-closed boundary is highly complex due to the complexity of the photospheric flux distribution. Second, this boundary is continuously driven by the transport of magnetic helicity from the closed field region into the open. The implications of this model for the structure and dynamics of the corona and slow wind are discussed, and observational tests of the mode

  6. Unveiling the Origin of Cosmic Rays

    NASA Astrophysics Data System (ADS)

    Olinto, Angela V.

    2015-04-01

    The origin of cosmic rays, relativistic particles that range from below GeVs to hundreds of EeVs, is a century old mystery. Extremely energetic phenomena occurring over a wide range of scales, from the Solar System to distant galaxies, are needed to explain the non-thermal particle spectrum that covers over 12 orders of magnitude. Space Missions are the most effective platforms to study the origin and history of these cosmic particles. Current missions probe particle acceleration and propagation in the Solar System and in our Galaxy. This year ISS-CREAM and CALET join AMS in establishing the International Space Station as the most active site for studying the origin of Galactic cosmic rays. These missions will study astrophysical cosmic ray accelerators as well as other possible sources of energetic particles such as dark matter annihilation or decay. In the future, the ISS may also be the site for studying extremely high-energy extragalactic cosmic rays with JEM-EUSO. We review recent results in the quest for unveiling the sources of energetic particles with balloons and space payloads and report on activities of the Cosmic ray Science Interest Group (CosmicSIG) under the Physics of the Cosmos Program Analysis Group (PhysPAG).

  7. A Strategy for Origins of Life Research.

    PubMed

    Scharf, Caleb; Virgo, Nathaniel; Cleaves, H James; Aono, Masashi; Aubert-Kato, Nathanael; Aydinoglu, Arsev; Barahona, Ana; Barge, Laura M; Benner, Steven A; Biehl, Martin; Brasser, Ramon; Butch, Christopher J; Chandru, Kuhan; Cronin, Leroy; Danielache, Sebastian; Fischer, Jakob; Hernlund, John; Hut, Piet; Ikegami, Takashi; Kimura, Jun; Kobayashi, Kensei; Mariscal, Carlos; McGlynn, Shawn; Menard, Brice; Packard, Norman; Pascal, Robert; Pereto, Juli; Rajamani, Sudha; Sinapayen, Lana; Smith, Eric; Switzer, Christopher; Takai, Ken; Tian, Feng; Ueno, Yuichiro; Voytek, Mary; Witkowski, Olaf; Yabuta, Hikaru

    2015-12-01

    Contents 1. Introduction 1.1. A workshop and this document 1.2. Framing origins of life science 1.2.1. What do we mean by the origins of life (OoL)? 1.2.2. Defining life 1.2.3. How should we characterize approaches to OoL science? 1.2.4. One path to life or many? 2. A Strategy for Origins of Life Research 2.1. Outcomes-key questions and investigations 2.1.1. Domain 1: Theory 2.1.2. Domain 2: Practice 2.1.3. Domain 3: Process 2.1.4. Domain 4: Future studies 2.2. EON Roadmap 2.3. Relationship to NASA Astrobiology Roadmap and Strategy documents and the European AstRoMap   Appendix I   Appendix II   Supplementary Materials  References.

  8. Origin of Hawking radiation: firewall or atmosphere?

    NASA Astrophysics Data System (ADS)

    Kim, Wontae

    2017-02-01

    The Unruh vacuum not admitting any outgoing flux at the horizon implies that the origin of the outgoing Hawking radiation is the atmosphere of a near-horizon quantum region without resort to the firewall; however, the existence of the firewall of superplanckian excitations at the horizon can be supported by the infinite Tolman temperature at the horizon. In an exactly soluble model, we explicitly show that the firewall necessarily emerges out of the Unruh vacuum so that the Tolman temperature in the Unruh vacuum is divergent in essence due to the infinitely blueshifted negative ingoing flux crossing the horizon rather than the outgoing flux. We also show that the outgoing Hawking radiation in the Unruh vacuum indeed originates from the atmosphere, not just at the horizon, which is of no relevance to the infinite blueshift. Consequently, the firewall from the infinite Tolman temperature and the Hawking radiation from the atmosphere turn out to be compatible, once we waive the claim that the Hawking radiation in the Unruh vacuum originates from the infinitely blueshifted outgoing excitations at the horizon.

  9. On the Origin of Polar Vortex Air

    NASA Technical Reports Server (NTRS)

    Rosenfield, J. E.; Schoeberl, M. R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The existence of the multi-year HALOE CH4 data set, together with some comparisons of forward with back trajectory calculations which we have carried out, has motivated us to reexamine the question of polar vortex descent. Three-dimensional diabatic trajectory calculations have been carried out for the seven month fall to spring period in both the northern hemisphere (NH) and southern hemisphere (SH) polar stratosphere for the years 1992-1999. These computations are compared to fixed descent computations where the parcels were fixed at their latitude-longitude locations and allowed to descend without circulating. The forward trajectory computed descent is always less than the fixed descent due to horizontal parcel motions and variations in heating rates with latitude and longitude. Although the forward calculations estimate the maximum amount of descent that can occur, they do not necessarily indicate the actual origin of springtime vortex air. This is because more equator-ward air can be entrained within the vortex during its formation. To examine the origin of the springtime vortex air, the trajectory model was run backward for seven months from spring to fall. The back trajectories show a complex distribution of parcels in which one population originates in the upper stratosphere and mesosphere and experiences considerable descent in the polar regions, while the remaining parcels originate at lower altitudes of the middle and lower stratosphere and are mixed into the polar regions during vortex formation without experiencing as much vertical transport. The amount of descent experienced by the first population shows little variability from year to year, while the computed descent and mixing of the remaining parcels show considerable interannual variability due to the varying polar meteorology. Because of this complex parcel distribution it is not meaningful to speak of a net amount of descent experienced over the entire winter period. Since the back trajectories

  10. Origin and evolution of spliceosomal introns

    PubMed Central

    2012-01-01

    Evolution of exon-intron structure of eukaryotic genes has been a matter of long-standing, intensive debate. The introns-early concept, later rebranded ‘introns first’ held that protein-coding genes were interrupted by numerous introns even at the earliest stages of life's evolution and that introns played a major role in the origin of proteins by facilitating recombination of sequences coding for small protein/peptide modules. The introns-late concept held that introns emerged only in eukaryotes and new introns have been accumulating continuously throughout eukaryotic evolution. Analysis of orthologous genes from completely sequenced eukaryotic genomes revealed numerous shared intron positions in orthologous genes from animals and plants and even between animals, plants and protists, suggesting that many ancestral introns have persisted since the last eukaryotic common ancestor (LECA). Reconstructions of intron gain and loss using the growing collection of genomes of diverse eukaryotes and increasingly advanced probabilistic models convincingly show that the LECA and the ancestors of each eukaryotic supergroup had intron-rich genes, with intron densities comparable to those in the most intron-rich modern genomes such as those of vertebrates. The subsequent evolution in most lineages of eukaryotes involved primarily loss of introns, with only a few episodes of substantial intron gain that might have accompanied major evolutionary innovations such as the origin of metazoa. The original invasion of self-splicing Group II introns, presumably originating from the mitochondrial endosymbiont, into the genome of the emerging eukaryote might have been a key factor of eukaryogenesis that in particular triggered the origin of endomembranes and the nucleus. Conversely, splicing errors gave rise to alternative splicing, a major contribution to the biological complexity of multicellular eukaryotes. There is no indication that any prokaryote has ever possessed a spliceosome

  11. Origin and evolution of spliceosomal introns.

    PubMed

    Rogozin, Igor B; Carmel, Liran; Csuros, Miklos; Koonin, Eugene V

    2012-04-16

    Evolution of exon-intron structure of eukaryotic genes has been a matter of long-standing, intensive debate. The introns-early concept, later rebranded 'introns first' held that protein-coding genes were interrupted by numerous introns even at the earliest stages of life's evolution and that introns played a major role in the origin of proteins by facilitating recombination of sequences coding for small protein/peptide modules. The introns-late concept held that introns emerged only in eukaryotes and new introns have been accumulating continuously throughout eukaryotic evolution. Analysis of orthologous genes from completely sequenced eukaryotic genomes revealed numerous shared intron positions in orthologous genes from animals and plants and even between animals, plants and protists, suggesting that many ancestral introns have persisted since the last eukaryotic common ancestor (LECA). Reconstructions of intron gain and loss using the growing collection of genomes of diverse eukaryotes and increasingly advanced probabilistic models convincingly show that the LECA and the ancestors of each eukaryotic supergroup had intron-rich genes, with intron densities comparable to those in the most intron-rich modern genomes such as those of vertebrates. The subsequent evolution in most lineages of eukaryotes involved primarily loss of introns, with only a few episodes of substantial intron gain that might have accompanied major evolutionary innovations such as the origin of metazoa. The original invasion of self-splicing Group II introns, presumably originating from the mitochondrial endosymbiont, into the genome of the emerging eukaryote might have been a key factor of eukaryogenesis that in particular triggered the origin of endomembranes and the nucleus. Conversely, splicing errors gave rise to alternative splicing, a major contribution to the biological complexity of multicellular eukaryotes. There is no indication that any prokaryote has ever possessed a spliceosome or

  12. 32 CFR 1907.23 - Response by originator(s) and/or any interested party.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... INTELLIGENCE AGENCY CHALLENGES TO CLASSIFICATION OF DOCUMENTS BY AUTHORIZED HOLDERS PURSUANT TO § 1.9 OF... authorized holder as well as the business requirements of the originator including their...

  13. 32 CFR 1907.23 - Response by originator(s) and/or any interested party.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... INTELLIGENCE AGENCY CHALLENGES TO CLASSIFICATION OF DOCUMENTS BY AUTHORIZED HOLDERS PURSUANT TO § 1.9 OF... authorized holder as well as the business requirements of the originator including their...

  14. 7 CFR 800.117 - Who shall perform original services.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Who shall perform original services. 800.117 Section 800.117 Agriculture Regulations of the Department of Agriculture (Continued) GRAIN INSPECTION, PACKERS... REGULATIONS Original Services § 800.117 Who shall perform original services. (a) General. Original...

  15. 19 CFR 134.11 - Country of origin marking required.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Country of origin marking required. 134.11 Section... OF THE TREASURY COUNTRY OF ORIGIN MARKING Articles Subject to Marking § 134.11 Country of origin... English name of the country of origin of the article, at the time of importation into the...

  16. 19 CFR 102.23 - Origin and Manufacturer Identification

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...; DEPARTMENT OF THE TREASURY RULES OF ORIGIN Rules of Origin § 102.23 Origin and Manufacturer Identification (a) Textile or apparel product manufacturer identification. All commercial importations of textile or apparel... 19 Customs Duties 1 2014-04-01 2014-04-01 false Origin and Manufacturer Identification...

  17. 19 CFR 102.23 - Origin and Manufacturer Identification

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...; DEPARTMENT OF THE TREASURY RULES OF ORIGIN Rules of Origin § 102.23 Origin and Manufacturer Identification (a) Textile or apparel product manufacturer identification. All commercial importations of textile or apparel... 19 Customs Duties 1 2012-04-01 2012-04-01 false Origin and Manufacturer Identification...

  18. 19 CFR 102.23 - Origin and Manufacturer Identification

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...; DEPARTMENT OF THE TREASURY RULES OF ORIGIN Rules of Origin § 102.23 Origin and Manufacturer Identification (a) Textile or apparel product manufacturer identification. All commercial importations of textile or apparel... 19 Customs Duties 1 2013-04-01 2013-04-01 false Origin and Manufacturer Identification...

  19. On the origin of lunar magnetization (Invited)

    NASA Astrophysics Data System (ADS)

    Wieczorek, M. A.; Weiss, B. P.

    2009-12-01

    The origin of lunar remanent magnetization has remained an enigmatic topic ever since the first magnetic fields of lunar origin were detected during the Apollo era. Although the Moon does not at present possess a dipolar field of internal origin, it is possible that the lunar core might have once powered a geodynamo in its early history. Such a field, if stable in direction over thousands of years, could have magnetized lavas at the surface and magmatic intrusions deep in the crust. In contrast, some of the strongest magnetic anomalies appear to be correlated with impact structures, such as near the antipodes of large basins, and this observation has led to the hypothesis that transient magnetic fields generated during impact events might be responsible for magnetizing some portions of the lunar crust. Both hypotheses possess theoretical obstacles that may or may not be overcome in the future. One manner by which we might hope to distinguish transient impact-generated fields from those of an internal dynamo would be to constrain the depths of magnetization within the crust. If the sources of the magnetic anomalies are surface basalt flows or the deep crust, this might provide evidence for a thermoremanent magnetization acquired by slow cooling in the presence of geodynamo. In contrast, if the magnetic anomalies are all associated with non-magmatic surficial deposits, then these could perhaps represent impact ejecta magnetized by transient fields. Shock remanent magnetization (SRM) processes could perhaps give rise to magnetizations deep in the crust, but these regions would be expected to be spatially correlated with impact craters. Unfortunately, magnetic fields observed from orbit alone cannot constrain uniquely the depths of magnetization. Nevertheless, when combined with reasonable geologic assumptions and sample constraints, it becomes possible to place bounds on the source geometry. In this work, spatial and spectral approaches will be used to constrain the

  20. The Origin of the Moon and Triton

    NASA Astrophysics Data System (ADS)

    Johnson, F. M.

    2004-12-01

    In 1879, George Darwin(1) had proposed that the moon originated from a rapidly spinning Earth on which equatorial gravitative attraction was nearly overcome by centrifical force. During a 1964 conference, D.U. Wise(2) and others analyzed this hypothesis in greater detail. However, recent studies warranted a fundamentally new approach with regards to the origin of the solar system. A re-examination of the spin-off (fission) hypothesis of the moon from the earth, using slightly different assumptions than scientists had previously used (allowing for a more extreme version of an expanding earth), provided the earth's original radius (357 km), density (3.13 x 104 g/cc) and spin rate (0.132 radians/sec.). It was found that Neptune underwent a similar development with the fission of Triton. The remarkably large initial densities, of both Earth and Neptune (7.2 x 105 gm/cc) are consistent with the overall theory(3,4) previously discussed regarding the evolution of the solar system from a neutron star type proto-sun's dense core. The primary calculations involve conservation of angular momentum of each of the rotating and revolving planetary systems. (1) Darwin, G. H. Phil. Trans. Roy. Soc. (London) 170, 1 (1879) (2) D.U. Wise, ``The Earth-Moon System" p. 213, Marsden and Cameron Eds. Plenum Press (1966) (3) Fred M. Johnson, ``Voyage Into Astronomy", Kendall/ Hunt Publ., (1977) (4) Fred M. Johnson, Mem. Soc. Roy. des Sciences de Liége, 6th series, vol. III, p. 609-627 (1972).

  1. Origins of the current seventh cholera pandemic.

    PubMed

    Hu, Dalong; Liu, Bin; Feng, Lu; Ding, Peng; Guo, Xi; Wang, Min; Cao, Boyang; Reeves, Peter R; Wang, Lei

    2016-11-29

    Vibrio cholerae has caused seven cholera pandemics since 1817, imposing terror on much of the world, but bacterial strains are currently only available for the sixth and seventh pandemics. The El Tor biotype seventh pandemic began in 1961 in Indonesia, but did not originate directly from the classical biotype sixth-pandemic strain. Previous studies focused mainly on the spread of the seventh pandemic after 1970. Here, we analyze in unprecedented detail the origin, evolution, and transition to pandemicity of the seventh-pandemic strain. We used high-resolution comparative genomic analysis of strains collected from 1930 to 1964, covering the evolution from the first available El Tor biotype strain to the start of the seventh pandemic. We define six stages leading to the pandemic strain and reveal all key events. The seventh pandemic originated from a nonpathogenic strain in the Middle East, first observed in 1897. It subsequently underwent explosive diversification, including the spawning of the pandemic lineage. This rapid diversification suggests that, when first observed, the strain had only recently arrived in the Middle East, possibly from the Asian homeland of cholera. The lineage migrated to Makassar, Indonesia, where it gained the important virulence-associated elements Vibrio seventh pandemic island I (VSP-I), VSP-II, and El Tor type cholera toxin prophage by 1954, and it then became pandemic in 1961 after only 12 additional mutations. Our data indicate that specific niches in the Middle East and Makassar were important in generating the pandemic strain by providing gene sources and the driving forces for genetic events.

  2. Developmental origins of inflammatory and immune diseases.

    PubMed

    Chen, Ting; Liu, Han-Xiao; Yan, Hui-Yi; Wu, Dong-Mei; Ping, Jie

    2016-08-01

    Epidemiological and experimental animal studies show that suboptimal environments in fetal and neonatal life exert a profound influence on physiological function and risk of diseases in adult life. The concepts of the 'developmental programming' and Developmental Origins of Health and Diseases (DOHaD) have become well accepted and have been applied across almost all fields of medicine. Adverse intrauterine environments may have programming effects on the crucial functions of the immune system during critical periods of fetal development, which can permanently alter the immune function of offspring. Immune dysfunction may in turn lead offspring to be susceptible to inflammatory and immune diseases in adulthood. These facts suggest that inflammatory and immune disorders might have developmental origins. In recent years, inflammatory and immune disorders have become a growing health problem worldwide. However, there is no systematic report in the literature on the developmental origins of inflammatory and immune diseases and the potential mechanisms involved. Here, we review the impacts of adverse intrauterine environments on the immune function in offspring. This review shows the results from human and different animal species and highlights the underlying mechanisms, including damaged development of cells in the thymus, helper T cell 1/helper T cell 2 balance disturbance, abnormal epigenetic modification, effects of maternal glucocorticoid overexposure on fetal lymphocytes and effects of the fetal hypothalamic-pituitary-adrenal axis on the immune system. Although the phenomena have already been clearly implicated in epidemiologic and experimental studies, new studies investigating the mechanisms of these effects may provide new avenues for exploiting these pathways for disease prevention.

  3. Origins Space Telescope: Cosmology and Reionization

    NASA Astrophysics Data System (ADS)

    Vieira, Joaquin D.; Origins Space Telescope Study Team

    2017-01-01

    The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, a study in development by NASA in preparation for the 2020 Astronomy and Astrophysics Decadal Survey. Origins is planned to be a large aperture, actively-cooled telescope covering a wide span of the mid- to far-infrared spectrum. Its imagers and spectrographs will enable a variety of surveys of the sky that will discover and characterize the most distant galaxies, Milky-Way, exoplanets, and the outer reaches of our Solar system. Origins will enable flagship-quality general observing programs led by the astronomical community in the 2030s. The Science and Technology Definition Team (STDT) would like to hear your science needs and ideas for this mission. The team can be contacted at firsurveyor_info@lists.ipac.caltech.edu.A core science goal of the OST mission is to study the the cosmological history of star, galaxy, and structure formation into the epoch of reionization (EoR). OST will probe the birth of galaxies through warm molecular hydrogen emission during the cosmic dark ages. Utilizing the unique power of the infrared fine-structure emission lines, OST will trace the rise of metals from the first galaxies until today. It will quantify the dust enrichment history of the Universe, uncover its composition and physical conditions, reveal the first cosmic sources of dust, and probe the properties of the earliest star formation. OST will provide a detailed astrophysical probe into the condition of the intergalactic medium at z > 6 and the galaxies which dominate the epoch of reionization.

  4. Chance of Necessity: Modeling Origins of Life

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew

    2006-01-01

    The fundamental nature of processes that led to the emergence of life has been a subject of long-standing debate. One view holds that the origin of life is an event governed by chance, and the result of so many random events is unpredictable. This view was eloquently expressed by Jacques Monod in his book Chance or Necessity. In an alternative view, the origin of life is considered a deterministic event. Its details need not be deterministic in every respect, but the overall behavior is predictable. A corollary to the deterministic view is that the emergence of life must have been determined primarily by universal chemistry and biochemistry rather than by subtle details of environmental conditions. In my lecture I will explore two different paradigms for the emergence of life and discuss their implications for predictability and universality of life-forming processes. The dominant approach is that the origin of life was guided by information stored in nucleic acids (the RNA World hypothesis). In this view, selection of improved combinations of nucleic acids obtained through random mutations drove evolution of biological systems from their conception. An alternative hypothesis states that the formation of protocellular metabolism was driven by non-genomic processes. Even though these processes were highly stochastic the outcome was largely deterministic, strongly constrained by laws of chemistry. I will argue that self-replication of macromolecules was not required at the early stages of evolution; the reproduction of cellular functions alone was sufficient for self-maintenance of protocells. In fact, the precise transfer of information between successive generations of the earliest protocells was unnecessary and could have impeded the discovery of cellular metabolism. I will also show that such concepts as speciation and fitness to the environment, developed in the context of genomic evolution also hold in the absence of a genome.

  5. Reconsidering the origins of Forsbergh birefringence patterns

    NASA Astrophysics Data System (ADS)

    Schilling, A.; Kumar, A.; McQuaid, R. G. P.; Glazer, A. M.; Thomas, P. A.; Gregg, J. M.

    2016-07-01

    In 1949, Forsbergh, Jr. reported spontaneous spatial ordering in the birefringence patterns seen in flux-grown BaTi O3 crystals under the transmission polarized light microscope [Phys. Rev. 76, 1187 (1949), 10.1103/PhysRev.76.1187]. Stunningly regular square-net arrays were often only found within a finite temperature window and could be induced on both heating and cooling, suggesting genuine thermodynamic stability. At the time, Forsbergh rationalized the patterns to have resulted from the impingement of ferroelastic domains, creating a complex tessellation of variously shaped domain packets. However, no direct evidence for the intricate microstructural arrangement proposed by Forsbergh has subsequently been found. Moreover, there are no robust thermodynamic arguments to explain the finite region of thermal stability, its occurrence just below the Curie temperature, and the apparent increase in entropy associated with the loss of the Forsbergh pattern on cooling. Despite decades of research on ferroelectrics, this ordering phenomenon and its thermodynamic origin have hence remained a mystery. In this paper, we reexamine the microstructure of flux-grown BaTi O3 crystals, which show Forsbergh birefringence patterns. Given an absence of any obvious arrays of domain polyhedra or even regular shapes of domain packets, we suggest an alternative origin for the Forsbergh pattern in which sheets of orthogonally oriented ferroelastic stripe domains simply overlay one another. We show explicitly that the Forsbergh birefringence pattern occurs if the periodicity of the stripe domains is above a critical value. Moreover, by considering well-established semiempirical models, we show that the significant domain coarsening needed to generate the Forsbergh birefringence is fully expected in a finite window below the Curie temperature. We hence present a much more straightforward rationalization of the Forsbergh pattern than that originally proposed in which exotic thermodynamic

  6. Origin and Evolution of Saturn's Small Satellites

    NASA Astrophysics Data System (ADS)

    Charnoz, Sebastien; Salmon, J.; Crida, A.; Brahic, A.

    2009-09-01

    All Saturn’ small satellites, orbiting below Mimas'orbit, share some common physical and dynamical properties : they have strong water absorption bands (Poulet & Cuzzi, 2002 Icarus 160, 350-358, Cuzzi et al., in press) , they have strange and elongated shapes and are under dense (Charnoz et al, 2007 Science 318, 1622, Porco et al. 2007 Science 318, 1602). They are also dynamically coupled with Saturn rings. In addition, due to their small size, they should not be primordial because of the meteoroid bombardment. They dynamically evolve under the tidal torque of the planet and the rings, in addition to satellite's perturbations. A theory of their origin still needs to be done. We show in the present work that these small satellites may be the natural result of the viscous spreading of Saturn's rings. Using a new 1D coupled hydrodynamic + dynamical evolution code, we compute that the rings viscous spreading may naturally form a population of 10-50 km size satellites, with and orbital organisation similar to the today population of small satellites. Self-regulation processes are at work limiting the maximum mass of small satellite to about the mass of Janus, consistently with observations. This satellite formation scenario of a new kind (due to the viscous spreading of a disk) seems to explain the composition, the shape, the total mass, and the low density of Saturn's small satellites. It would give also an interesting explanation to the origin of the F ring. In conclusion, Saturn's small satellites may be considered as a specific category of satellites whose origin is very different either from Saturn's main satellites of Saturn's captured satellites. They could be the "children” of the rings.

  7. Origin of 78235, a lunar norite cumulate

    NASA Technical Reports Server (NTRS)

    Winzer, S. R.; Nava, D. F.; Lum, R. K. L.; Schuhmann, S.; Schuhmann, P.; Philpotts, J. A.

    1975-01-01

    A chemical and petrographic study is reported of the phases from the rock 78235 which was returned on the Apollo 17 mission. Petrographic analysis of the thin sections from the bounder confirm its cumulate origin. In order to develop further the crystallization history for 78235, its subsequent shock history, and its relationship to other lunar crustal rocks, orthopyroxene, plagioclase, glass, and whole-rock samples were prepared and analyzed for major, minor, and trace elements. It is speculated that an early fractional crystallization event producing a layer of orthopyroxene-plagioclase cumulate with varying amounts of trapped liquid took place within 20 km of the surface of the moon.

  8. Mythological and Prehistorical Origins of Neurosurgery.

    PubMed

    Nanda, Anil; Filis, Andreas; Kalakoti, Piyush

    2016-05-01

    Mythology has a cultural appeal, and the description of some neurosurgical procedures in the Hindu, Greek, Egyptian, and Chinese mythology has a bearing to the origins of our professions. The traces to some of our modern-day practices also can be linked back to the ancient prehistoric eras of the Siberian, Persian, and the Andean region. In this historical perspective, we briefly dwell into individual accounts through the prism of different cultures to highlight the development of neurosurgery in mythology and prehistoric era.

  9. The origin of the pion mass

    NASA Astrophysics Data System (ADS)

    Kocić, Aleksander

    1988-06-01

    We discuss the origin of the pion mass using a simple model of the QCD vacuum as a condensate of overlapping quark-antiquark pairs. We analyze the relationship between local conservation of the axial current and the nonzero current quark mass. Away from the chiral limit, we find that the pion mass comes from a change in the geometry of the overlap of condensed pairs. We wish to thank Lee Brekke, Vijay Pandharipande, and Bob Thews for their interest and useful discussions. We acknowledge the hospitality of the Physics Department of the University of Illinois where part of this work was done.

  10. On the Origins of Solar EIT Waves

    DTIC Science & Technology

    2005-09-20

    Domingo et al. 1995), launched in 1995 December, made it pos- 2. ANALYSIS sible to image wave motions in the solar corona (Thompson et al. 2.1...Poland, A. 1. 1995, So!. Phys., 162, 1 Smith, S. F., & Harvey, K. L. 197 1, in Physics of the Solar Corona , ed. C. J. Drake, J. F. 1971, Sol. Phys., 16...Printed in U.S.A. DISTRIBUTION STATEMENT A ON THE ORIGINS OF SOLAR EIT WAVES Approved for Public Release E. W. CLIVER Distribution Unlimited Space

  11. Hydrothermal vents and the origin of life.

    PubMed

    Martin, William; Baross, John; Kelley, Deborah; Russell, Michael J

    2008-11-01

    Submarine hydrothermal vents are geochemically reactive habitats that harbour rich microbial communities. There are striking parallels between the chemistry of the H(2)-CO(2) redox couple that is present in hydrothermal systems and the core energy metabolic reactions of some modern prokaryotic autotrophs. The biochemistry of these autotrophs might, in turn, harbour clues about the kinds of reactions that initiated the chemistry of life. Hydrothermal vents thus unite microbiology and geology to breathe new life into research into one of biology's most important questions - what is the origin of life?

  12. The deuterostome context of chordate origins.

    PubMed

    Lowe, Christopher J; Clarke, D Nathaniel; Medeiros, Daniel M; Rokhsar, Daniel S; Gerhart, John

    2015-04-23

    Our understanding of vertebrate origins is powerfully informed by comparative morphology, embryology and genomics of chordates, hemichordates and echinoderms, which together make up the deuterostome clade. Striking body-plan differences among these phyla have historically hindered the identification of ancestral morphological features, but recent progress in molecular genetics and embryology has revealed deep similarities in body-axis formation and organization across deuterostomes, at stages before morphological differences develop. These developmental genetic features, along with robust support of pharyngeal gill slits as a shared deuterostome character, provide the foundation for the emergence of chordates.

  13. The McAndrews Leadership Lecture: Origins

    PubMed Central

    Hamm, Anthony W.; Burkhart, Lori A.

    2015-01-01

    Objective This article describes the origins and rationale for the McAndrews Leadership Lecture and explains why the American Chiropractic Association honors George and Jerome McAndrews. Discussion George and Jerome McAndrews’ backgrounds demonstrate their leadership contributions to the chiropractic profession. Jerome McAndrews, a chiropractor, held substantial leadership roles in the chiropractic profession. George McAndrews, a lawyer, administered a permanent injunction forbidding the American Medical Association’s restraint of trade toward the chiropractic profession. Conclusion The American Chiropractic Association has established the McAndrews Leadership Lecture to honor their contributions to the chiropractic profession. PMID:26770176

  14. The origins of major platelet receptor nomenclature.

    PubMed

    Clemetson, Kenneth J

    2017-01-01

    The nomenclature of the major platelet receptors may appear complex, but in fact there are logical reasons why it developed in the way it did. In this short review, I describe the origins of this nomenclature, how it developed as more information became available and as relationships were established with receptors on other types of cells. Difficulties have also arisen with alternative nomenclature systems and the various equivalences with these are described and listed. There remain areas such as immunology and transfusion where the accepted nomenclature leaves something to be desired, but it is unlikely that major changes will occur.

  15. Cliftonite in meteorites: A proposed origin

    USGS Publications Warehouse

    Brett, R.; Higgins, G.T.

    1967-01-01

    Cliftonite, a polycrystalline aggregate of graphite with cubic morphology, is known in ten meteorites. Some workers have considered it to be a pseudomorph after diamond, and have used the proposed diamond ancestry as evidence of a meteoritic parent body of at least lunar dimensions. We have synthesized cliftonite in Fe-Ni-C alloys in vacuum, as a product of decomposition of cohenite [(Fe,Ni)3C]. We therefore suggest that a high pressure origin is unnecessary for meteorites which contain cliftonite, and that these meteorites were formed at low pressures. This conclusion is in agreement with other recent evidence.

  16. Origins of species: acquired genomes and individuality

    NASA Technical Reports Server (NTRS)

    Margulis, L.

    1993-01-01

    Entire genomes with their accompanying protein synthetic systems are transferred throughout the biosphere primarily as bacteria and protists which become symbionts as they irreversibly integrate into pre-existing organisms to form more complex individuals. Individualization is stabilized by simultaneous transmission of once-separate heterologous genetic systems. The origin of new species is hypothesized to correlate with the acquisition, integration and subsequent inheritance of such acquired microbial genomes. These processes were recognized by Mereschkovsky ("Symbiogenesis" in Russian, 1909) and by Wallin ("Symbionticism", see p. 181, this issue).

  17. The Original Apollo 13 Prime Crew

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The original Apollo 13 prime crew. From left to right are: Commander, James A. Lovell, Command Module pilot, Thomas K. Mattingly and Lunar Module pilot, Fred W. Haise. On the table in front of them are from left to right, a model of a sextant, the Apollo 13 insignia, and a model of an astrolabe. The sextant and astrolabe are two ancient forms of navigation. Command Module pilot Thomas 'Ken' Mattingly was exposed to German measles prior to his mission and was replaced by his backup, Command Module pilot, John L.'Jack' Swigert Jr.

  18. The Atomic Origin of the Reflection Law

    NASA Astrophysics Data System (ADS)

    Prytz, Kjell

    2016-12-01

    It will be demonstrated how the reflection law may be derived on an atomic basis using the plane wave approximation together with Huygens' principle. The model utilized is based on the electric dipole character of matter originating from its molecular constituents. This approach is not new but has, since it was first introduced by Ewald and Oseen in 1915, been applied and analyzed many times before. Here we develop the Ewald-Oseen model of reflection adapted for high school and early undergraduate students with a basic knowledge of microscopic material structure.

  19. Origin of a peculiar extra U(1)

    SciTech Connect

    Barr, S.M.; Dorsner, I.

    2005-07-01

    The origin of a family-independent ''extra U(1)'', discovered by Barr, Bednarz, and Benesh and independently by Ma, and whose phenomenology has recently been studied by Ma and Roy, is discussed. Even though it satisfies anomaly constraints in a highly economical way, with just a single extra triplet of leptons per family, this extra U(1) cannot come from four-dimensional grand unification. However, it is shown here that it can come from a Pati-Salam scheme with an extra U(1), which explains the otherwise surprising cancellation of anomalies.

  20. The origin of the big-bang

    NASA Astrophysics Data System (ADS)

    Thakur, R. K.

    1992-04-01

    A singularity-free model of the universe is developed within the framework of the Friedmann-Lemaitre-Robertson-Walker cosmology, which gives a physical explanation for the origin of the big bang and for the preponderance of matter over antimatter. It is shown that the model retains all the useful features of the standard-cosmology (Weinberg, 1972; Sandage, 1988) hot big-bang (HBB) model and resolves, in a very natural way, all the difficulties of the HBB model, such as the occurrence of space-time singularity. The new model also resolves the problem of the baryon asymmetry and can accont for the currently observed value of nu.

  1. Did Darwin write the Origin backwards?

    PubMed Central

    Sober, Elliott

    2009-01-01

    After clarifying how Darwin understood natural selection and common ancestry, I consider how the two concepts are related in his theory. I argue that common ancestry has evidential priority. Arguments about natural selection often make use of the assumption of common ancestry, whereas arguments for common ancestry do not require the assumption that natural selection has been at work. In fact, Darwin held that the key evidence for common ancestry comes from characters whose evolution is not caused by natural selection. This raises the question of why Darwin puts natural selection first and foremost in the Origin. PMID:19528655

  2. Ureilites - Trace element clues to their origin

    NASA Technical Reports Server (NTRS)

    Janssens, Marie-Josee; Hertogen, Jan; Wolf, Rainer; Ebihara, Mitsuru; Anders, Edward

    1987-01-01

    The question of the origin of ureilites was reexamined using new data obtained by radiochemical NAA for Ag, Au, Bi, Br, Cd, Cs, Ge, In, Ir, Ni, Pd, Os, Rb, Re, Sb, Se, Te, Tl, U, and Zn in two vein separates from Haveroe and Kenna and a bulk sample of Kenna. Vein material was found to be enriched in all elements analyzed, except Zn, and to account for most of the carbon, noble gases, and, presumably, siderophiles in the meteorite. The results support the earlier interpretation of Higuchi et al. (1976) on the composition of ureilite parent body (similar to C3V or H3, but not C3O chondrites).

  3. Space exploration and the origin of life.

    NASA Technical Reports Server (NTRS)

    Young, R. S.

    1972-01-01

    An important aspect of space exploration is connected with investigations regarding the existence of life on other celestial bodies. The most important objects to be studied for this purpose include the planets, the satellites of planets, meteorites, asteroids, and comets. The exploration of Mars, in particular, beginning with the telescope, fly-by and orbiting spacecraft, followed by landed laboratories, and perhaps culminating eventually in manned expeditions, may well provide a significant portion of the data we seek about the origin of life and introduce a new era of understanding of man's place in the universe.

  4. Probable origins of trachoma in Australasia

    PubMed Central

    Mann, Ida

    1957-01-01

    The history of trachoma in Australasia is reviewed; it is suggested that the disease was not originally endemic in the area, but that it was introduced by European and Chinese settlers, first into Australia and later into New Guinea. From surveys undertaken by the author, and also from those made by others during the past ten years, it is concluded that “pure trachoma” exists all over the area and is still spreading inland from the coast, and that it is converted into the serious type of the disease by secondary infection and mechanical irritation. PMID:13479769

  5. Language and the origin of numerical concepts.

    PubMed

    Gelman, Rochel; Gallistel, C R

    2004-10-15

    Reports of research with the Pirahã and Mundurukú Amazonian Indians of Brazil lend themselves to discussions of the role of language in the origin of numerical concepts. The research findings indicate that, whether or not humans have an extensive counting list, they share with nonverbal animals a language-independent representation of number, with limited, scale-invariant precision. What causal role, then, does knowledge of the language of counting serve? We consider the strong Whorfian proposal, that of linguistic determinism; the weak Whorfian hypothesis, that language influences how we think; and that the "language of thought" maps to spoken language or symbol systems.

  6. Genomics and the origin of species.

    PubMed

    Seehausen, Ole; Butlin, Roger K; Keller, Irene; Wagner, Catherine E; Boughman, Janette W; Hohenlohe, Paul A; Peichel, Catherine L; Saetre, Glenn-Peter; Bank, Claudia; Brännström, Ake; Brelsford, Alan; Clarkson, Chris S; Eroukhmanoff, Fabrice; Feder, Jeffrey L; Fischer, Martin C; Foote, Andrew D; Franchini, Paolo; Jiggins, Chris D; Jones, Felicity C; Lindholm, Anna K; Lucek, Kay; Maan, Martine E; Marques, David A; Martin, Simon H; Matthews, Blake; Meier, Joana I; Möst, Markus; Nachman, Michael W; Nonaka, Etsuko; Rennison, Diana J; Schwarzer, Julia; Watson, Eric T; Westram, Anja M; Widmer, Alex

    2014-03-01

    Speciation is a fundamental evolutionary process, the knowledge of which is crucial for understanding the origins of biodiversity. Genomic approaches are an increasingly important aspect of this research field. We review current understanding of genome-wide effects of accumulating reproductive isolation and of genomic properties that influence the process of speciation. Building on this work, we identify emergent trends and gaps in our understanding, propose new approaches to more fully integrate genomics into speciation research, translate speciation theory into hypotheses that are testable using genomic tools and provide an integrative definition of the field of speciation genomics.

  7. Chronic Cutaneous Draining Sinus of Dental Origin

    PubMed Central

    Sisodia, N; Manjunath, MK

    2014-01-01

    Extra oral sinus of odontogenic origin occurs when the purulent by-products of dental pulp necrosis spread along the path of least resistance from the root apex to the skin on the face. Patients presenting with cutaneous sinus usually visit a general physician or dermatologist first, as the lesion can mimic various dermatologic pathologies, ranging from an infected sebaceous cysts to a basal cell carcinoma. Despite systemic antibiotics, symptoms often persist causing further confusion, and at times leading to unnecessary surgical interventions. The location of this sinus in the head and neck region should lead the physician to seek a dental opinion in order to avoid misdiagnosis. PMID:25506495

  8. The origin of ultra-compact binaries

    NASA Astrophysics Data System (ADS)

    Hachisu, Izumi; Miyaji, Shigeki; Saio, Hideyuki

    The origin of ultra-compact binaries composed of a neutron star and a low-mass (about 0.06 solar mass) white dwarf is considered. Taking account of the systemic losses of mass and angular momentum, it was found that a serious difficulty exists in the scenarios which involve tidal captures of a normal star (a main sequence star or a red giant) by a neutron star. This difficulty can be avoided if a red giant star is captured by a massive white dwarf (M is approx. greater than 1.2 solar masses), which becomes a neutron star through the accretion induced collapse.

  9. The evolutionary sequence: origin and emergences.

    PubMed

    Fox, S W

    1986-03-01

    The evolutionary sequence is being reexamined experimentally from a "Big Bang"origin to the protocell and from the emergence of protocell and variety of species to Darwin's mental power (mind) and society (The Descent of Man). A most fundamentally revisionary consequence of experiments is an emphasis on endogenous ordering. This principle, seen vividly in ordered copolymerization of amino acids, has had new impact on the theory of Darwinian evolution and has been found to apply to the entire sequence. Herein, I will discuss some problems of dealing with teaching controversial subjects.

  10. The evolutionary sequence: origin and emergences

    NASA Technical Reports Server (NTRS)

    Fox, S. W.

    1986-01-01

    The evolutionary sequence is being reexamined experimentally from a "Big Bang"origin to the protocell and from the emergence of protocell and variety of species to Darwin's mental power (mind) and society (The Descent of Man). A most fundamentally revisionary consequence of experiments is an emphasis on endogenous ordering. This principle, seen vividly in ordered copolymerization of amino acids, has had new impact on the theory of Darwinian evolution and has been found to apply to the entire sequence. Herein, I will discuss some problems of dealing with teaching controversial subjects.

  11. The Origins of the RNA World

    PubMed Central

    Robertson, Michael P; Joyce, Gerald F

    2012-01-01

    The general notion of an “RNA World” is that, in the early development of life on the Earth, genetic continuity was assured by the replication of RNA and genetically encoded proteins were not involved as catalysts. There is now strong evidence indicating that an RNA World did indeed exist before DNA- and protein-based life. However, arguments regarding whether life on Earth began with RNA are more tenuous. It might be imagined that all of the components of RNA were available in some prebiotic pool, and that these components assembled into replicating, evolving polynucleotides without the prior existence of any evolved macromolecules. A thorough consideration of this “RNA-first” view of the origin of life must reconcile concerns regarding the intractable mixtures that are obtained in experiments designed to simulate the chemistry of the primitive Earth. Perhaps these concerns will eventually be resolved, and recent experimental findings provide some reason for optimism. However, the problem of the origin of the RNA World is far from being solved, and it is fruitful to consider the alternative possibility that RNA was preceded by some other replicating, evolving molecule, just as DNA and proteins were preceded by RNA. PMID:20739415

  12. Synthetic Origin of Tramadol in the Environment.

    PubMed

    Kusari, Souvik; Tatsimo, Simplice Joel N; Zühlke, Sebastian; Spiteller, Michael

    2016-01-04

    The presence of tramadol in roots of Sarcocephalus latifolius trees in Northern Cameroon was recently attributed to point contamination with the synthetic compound. The synthetic origin of tramadol in the environment has now been unambiguously confirmed. Tramadol samples isolated from tramadol pills bought at a street market in downtown Maroua and highly contaminated soil at Houdouvou were analyzed by high-precision (14)C measurements by accelerator mass spectrometry ((14)C AMS): Tramadol from the pills did not contain any radiocarbon, thus indicating that it had been synthesized from (14)C-free petroleum-derived precursors. Crucially, tramadol isolated from the soil was also radiocarbon-free. As all biosynthetic plant compounds must contain radiocarbon levels close to that of the contemporary environment, these results thus confirm that tramadol isolated from the soil cannot be plant-derived. Analyses of S. latifolius seeds, in vitro grown plants, plants from different origins, and stable-isotope labeling experiments further confirmed that synthetic tramadol contaminates the environment.

  13. Origin of microseism observed in South Korea

    NASA Astrophysics Data System (ADS)

    Sheen, D.; Shin, J.; You, S.; Rhie, J.

    2009-12-01

    Ambient seismic noise has been widely used for imaging crustal structure as an alternative passive source, even where traditional seismic imaging is not possible due to low seismicity. Long before the sensational applications of seismic noise, the origin of the noise has already been studied to understand its nature and characteristics for several decades. In this study, we investigate the origin of microseism observed in South Korea. Annual spectrograms in the microseismic frequency range up to 0.4 Hz show coherent peaks at about 0.2 Hz in the winter, which is at the frequency band of the double-frequency microseism. However, the primary microseism is only rarely observed in South Korea when the Pacific typhoon is close to the Southern Sea of Korea. Polarization analysis and noise cross correlation indicate that the energy of the double-frequency microseism comes dominantly from the east of the Korean Peninsula. Comparison of the results from the operational wave model of the Korea Meteorological Administration and seismic data shows a strong correlation of spectral amplitude of seismic data with the significant wave heights and periods of ocean waves, implying that the primary and the double-frequency microseism observed in South Korea are generated at the Southern Sea of Korea and at nearby shorelines of the east coast of Japan, respectively.

  14. The evolutionary origin of an altruistic gene.

    PubMed

    Nedelcu, Aurora M; Michod, Richard E

    2006-08-01

    Although the conditions favoring altruism are being increasingly understood, the evolutionary origins of the genetic basis for this behavior remain elusive. Here, we show that reproductive altruism (i.e., a sterile soma) in the multicellular green alga, Volvox carteri, evolved via the co-option of a life-history gene whose expression in the unicellular ancestor was conditioned on an environmental cue (as an adaptive strategy to enhance survival at an immediate cost to reproduction) through shifting its expression from a temporal (environmentally induced) into a spatial (developmental) context. The gene belongs to a diverged and structurally heterogeneous multigene family sharing a SAND-like domain (a DNA-binding module involved in gene transcription regulation). To our knowledge, this is the first example of a social gene specifically associated with reproductive altruism, whose origin can be traced back to a solitary ancestor. These findings complement recent proposals that the differentiation of sterile castes in social insects involved the co-option of regulatory networks that control sequential shifts between phases in the life cycle of solitary insects.

  15. The origins and evolution of leadership.

    PubMed

    King, Andrew J; Johnson, Dominic D P; Van Vugt, Mark

    2009-10-13

    How groups of individuals achieve coordination and collective action is an important topic in the natural sciences, but until recently the role of leadership in this process has been largely overlooked. In contrast, leadership is arguably one of the most important themes in the social sciences, permeating all aspects of human social affairs: the election of Barack Obama, the war in Iraq, and the collapse of the banks are all high-profile events that draw our attention to the fundamental role of leadership and followership. Converging ideas and developments in both the natural and social sciences suggest that leadership and followership share common properties across humans and other animals, pointing to ancient roots and evolutionary origins. Here, we draw upon key insights from the animal and human literature to lay the foundation for a new science of leadership inspired by an evolutionary perspective. Identifying the origins of human leadership and followership, as well as which aspects are shared with other animals and which are unique, offers ways of understanding, predicting, and improving leadership today.

  16. Reptile thermogenesis and the origins of endothermy.

    PubMed

    Tattersall, Glenn J

    2016-10-01

    Extant endotherms have high rates of metabolism, elevated body temperatures, usually tight control over body temperature, and a reasonable scope for further increases in metabolism through locomotor activity. Vertebrate ectotherms, on the other hand, rely on behavioural thermoregulation and cardiovascular adjustments to facilitate warming, and generally lack specific biochemical and cellular mechanisms for sustained, elevated metabolism. Nevertheless, the ancestral condition to endothermy is thought to resemble that of many extant reptiles, which raises the question of the origins and selection pressures relevant to the transitional state. Numerous hypotheses have emerged to explain the multiple origins of endothermy in vertebrates, including thermoregulatory, locomotory, and reproductive activity as possible drivers for these sustained and elevated metabolic rates. In this article, I discuss recent evidence for facultative endothermy in an extant lepidosaur, the tegu lizard. Since lepidosaurs are a sister group to the archosaurs, understanding how a novel form of endothermy evolved will open up opportunities to test the compatibility or incompatibility of the various endothermy hypotheses, with potential to elucidate and resolve long contentious ideas in evolutionary physiology.

  17. Character displacement and the origins of diversity

    PubMed Central

    Pfennig, David W.; Pfennig, Karin S.

    2012-01-01

    In The Origin of Species, Darwin proposed his ‘principle of divergence of character’ (a process now termed ‘character displacement’) to explain how new species arise and why they differ from one other phenotypically. Darwin maintained that the origin of species, and the evolution of differences between them, is ultimately caused by divergent selection acting to minimize competitive interactions between initially similar individuals, populations, and species. Here, we examine the empirical support for the various claims that constitute Darwin’s principle, specifically that: (1) competition promotes divergent trait evolution; (2) the strength of competitively mediated divergent selection increases with increasing phenotypic similarity between competitors; (3) divergence can occur within species; and (4) competitively mediated divergence can trigger speciation. We also explore aspects that Darwin failed to consider. In particular, we describe how: (1) divergence can arise from selection acting to lessen reproductive interactions; (2) divergence is fueled by the intersection of character displacement and sexual selection; and (3) phenotypic plasticity may play a key role in promoting character displacement. Generally, character displacement is well supported empirically, and it remains a vital explanation for how new species arise and diversify. PMID:21043778

  18. Towards a Cancer Drug of Fungal Origin

    PubMed Central

    Kornienko, Alexander; Evidente, Antonio; Vurro, Maurizio; Mathieu, Véronique; Cimmino, Alessio; Evidente, Marco; van Otterlo, Willem A. L.; Dasari, Ramesh; Lefranc, Florence; Kiss, Robert

    2015-01-01

    Although fungi produce highly structurally diverse metabolites, many of which have served as excellent sources of pharmaceuticals, no fungi-derived agent has been approved as a cancer drug so far. This is despite a tremendous amount of research being aimed at the identification of fungal metabolites with promising anticancer activities. This review discusses the results of clinical testing of fungal metabolites and their synthetic derivatives, with the goal to evaluate how far we are from an approved cancer drug of fungal origin. Also, because in vivo studies in animal models are predictive of the efficacy and toxicity of a given compound in a clinical situation, literature describing animal cancer testing of compounds of fungal origin is reviewed as well. Agents showing the potential to advance to clinical trials are also identified. Finally, the technological challenges involved in the exploitation of fungal biodiversity and procurement of sufficient quantities of clinical candidates are discussed and potential solutions that could be pursued by researchers are highlighted. PMID:25850821

  19. Precambrian origins of the TNFR superfamily

    PubMed Central

    Quistad, S D; Traylor-Knowles, N

    2016-01-01

    The evolution of the tumor necrosis factor/tumor necrosis factor receptor superfamily (TNF/TNFR) is complicated and not well understood. To date, most TNFR studies have focused on vertebrate models leaving the role of TNFRs in invertebrates largely unexplored. The evolution of important cellular processes including stress response, apoptosis, development, and inflammation will be better understood by examining the TNF/TNFR superfamily in ancient invertebrate phyla. How widespread is this gene family within the evolutionary tree of life and is there evidence for similar function in invertebrates? A first step is to identify the presence or absence of these genes within basal metazoan taxa using the signature cysteine-rich domain (CRD) of the TNFR superfamily. In this perspective, we will start by examining what is currently known about the function of TNFRs in invertebrates. Then, we will assess the role of TNFRs in apoptosis and explore the origins of the domains found in TNFRs including the death domain (DD) and CRD. Finally, we will examine the phylogenetic relationship between TNFRs containing DDs identified to date. From these data, we propose a model for a Precambrian origin of TNFRs and their functional role in apoptosis. PMID:27551546

  20. Focus on the origin of matter

    NASA Astrophysics Data System (ADS)

    Di Bari, P.; Masiero, A.; Mohapatra, R.

    2013-03-01

    The origin of matter in the Universe is a fascinating cosmological puzzle that has triggered a formidable intellectual enterprise, started in 1967 with the prescient paper by Andrej Sakharov (1967 Pisma Zh. Eksp. Teor. Fiz. 5 32; 1967 JETP Lett. 52 4; 1991 Sov. Phys.—Usp. 34 392; 1991 Usp. Fiz. Nauk 161 61) aimed at relating a cosmological observation to the fundamental laws of physics, the goal of baryogenesis. A successful model of baryogenesis should ultimately identify the required source of charge parity violation and the origin of the cosmological matter-antimatter asymmetry. This focus issue is not only a review of the main ideas that have been proposed in baryogenesis but should also bear witness to the great vitality of the field and to show how future experimental results could bring a breakthrough in baryogenesis during the coming years. For this reason we selected, out of the multitude of proposed baryogenesis models, those that will more likely experience a significant experimental test during the coming years.

  1. Biogenic Origin for Earth's Oldest Putative Microfossils

    SciTech Connect

    De Gregorio, B.; Sharp, T; Flynn, G; Wirick, S; Hervig, R

    2009-01-01

    Carbonaceous microbe-like features preserved within a local chert unit of the 3.5 Ga old Apex Basalt in Western Australia may represent some of the oldest evidence of life on Earth. However, the biogenicity of these putative microfossils has been called into question, primarily because the sample collection locality is a black, carbon-rich, brecciated chert dike representing an Archean submarine hydrothermal spring, suggesting a formation via an abiotic organic synthesis mechanism. Here we describe the macromolecular hydrocarbon structure, carbon bonding, functional group chemistry, and biotic element abundance of carbonaceous matter associated with these filamentous features. These characteristics are similar to those of biogenic kerogen from the ca. 1.9 Ga old Gunflint Formation. Although an abiotic origin cannot be entirely ruled out, it is unlikely that known abiotic synthesis mechanisms could recreate both the structural and compositional complexity of this ancient carbonaceous matter. Thus, we find that a biogenic origin for this material is more likely, implying that the Apex microbe-like features represent authentic biogenic organic matter.

  2. On the origin of polar ion streams

    NASA Astrophysics Data System (ADS)

    Green, J. L.; Waite, J. H., Jr.

    1985-03-01

    It is reaffirmed in this reply that the 'classical' polar wind is based on the thermal escape of the light ions H(+) and He(+). It is asserted that the polar ion flow observations presented in the Gurgiolo and Burch (1985) comment paper, made by the High Altitude Plasma Instrument (HAPI) instrument on Dynamics Explorer-1 (DE), are O(+) and that the probable origin of these ions, which is consistent with the observations, is a highly localized region in the dayside polar cleft; this is a distinctly different source region than that of the polar wind. Velocity and mass selection, as a result of E x B convection acting on ions from a localized source region in the polar cusp or the dayside polar cap boundary, determines the measured HAPI ion distribution. The Retarding Ion Mass Spectrometer instrument on DE, during the same time period, was measuring the light ion polar wind with flow energies of less than 2.5 eV which originated in the polar cap ionosphere very near the north magnetic pole.

  3. Origins of food crops connect countries worldwide

    PubMed Central

    Achicanoy, Harold A.; Bjorkman, Anne D.; Navarro-Racines, Carlos; Guarino, Luigi; Flores-Palacios, Ximena; Engels, Johannes M. M.; Wiersema, John H.; Dempewolf, Hannes; Sotelo, Steven; Ramírez-Villegas, Julian; Castañeda-Álvarez, Nora P.; Fowler, Cary; Jarvis, Andy; Rieseberg, Loren H.; Struik, Paul C.

    2016-01-01

    Research into the origins of food plants has led to the recognition that specific geographical regions around the world have been of particular importance to the development of agricultural crops. Yet the relative contributions of these different regions in the context of current food systems have not been quantified. Here we determine the origins (‘primary regions of diversity’) of the crops comprising the food supplies and agricultural production of countries worldwide. We estimate the degree to which countries use crops from regions of diversity other than their own (‘foreign crops’), and quantify changes in this usage over the past 50 years. Countries are highly interconnected with regard to primary regions of diversity of the crops they cultivate and/or consume. Foreign crops are extensively used in food supplies (68.7% of national food supplies as a global mean are derived from foreign crops) and production systems (69.3% of crops grown are foreign). Foreign crop usage has increased significantly over the past 50 years, including in countries with high indigenous crop diversity. The results provide a novel perspective on the ongoing globalization of food systems worldwide, and bolster evidence for the importance of international collaboration on genetic resource conservation and exchange.

  4. Oceanic origin of southeast tropical Atlantic biases

    NASA Astrophysics Data System (ADS)

    Xu, Zhao; Li, Mingkui; Patricola, Christina M.; Chang, Ping

    2014-12-01

    Most coupled general circulation models suffer from a prominent warm sea surface temperature bias in the southeast tropical Atlantic Ocean off the coast of Africa. The origin of the bias is not understood and remains highly controversial. Previous studies suggest that the origin of the bias stems from systematic errors of atmospheric models in simulating surface heat flux and coastal wind, or poorly simulated coastal upwelling. In this study, we show, using different reanalysis and observational data sets combined with a set of eddy-resolving regional ocean model simulations, that systematic errors in ocean models also make a significant contribution to the bias problem. In particular (1) the strong warm bias at the Angola-Benguela front that is maintained by the local wind and the convergence of Angola and Benguela Currents is caused by an overshooting of the Angola Current in ocean models and (2) the alongshore warm bias to the south of the front is caused by ocean model deficiencies in simulating the sharp thermocline along the Angola coast, which is linked to biases in the equatorial thermocline, and the complex circulation system within the Benguela upwelling zone.

  5. Evolutionary origin of the turtle shell.

    PubMed

    Lyson, Tyler R; Bever, Gabe S; Scheyer, Torsten M; Hsiang, Allison Y; Gauthier, Jacques A

    2013-06-17

    The origin of the turtle shell has perplexed biologists for more than two centuries. It was not until Odontochelys semitestacea was discovered, however, that the fossil and developmental data could be synthesized into a model of shell assembly that makes predictions for the as-yet unestablished history of the turtle stem group. We build on this model by integrating novel data for Eunotosaurus africanus-a Late Guadalupian (∼260 mya) Permian reptile inferred to be an early stem turtle. Eunotosaurus expresses a number of relevant characters, including a reduced number of elongate trunk vertebrae (nine), nine pairs of T-shaped ribs, inferred loss of intercostal muscles, reorganization of respiratory muscles to the ventral side of the ribs, (sub)dermal outgrowth of bone from the developing perichondral collar of the ribs, and paired gastralia that lack both lateral and median elements. These features conform to the predicted sequence of character acquisition and provide further support that E. africanus, O. semitestacea, and Proganochelys quenstedti represent successive divergences from the turtle stem lineage. The initial transformations of the model thus occurred by the Middle Permian, which is congruent with molecular-based divergence estimates for the lineage, and remain viable whether turtles originated inside or outside crown Diapsida.

  6. Evidence for a recent origin of penguins.

    PubMed

    Subramanian, Sankar; Beans-Picón, Gabrielle; Swaminathan, Siva K; Millar, Craig D; Lambert, David M

    2013-01-01

    Penguins are a remarkable group of birds, with the 18 extant species living in diverse climatic zones from the tropics to Antarctica. The timing of the origin of these extant penguins remains controversial. Previous studies based on DNA sequences and fossil records have suggested widely differing times for the origin of the group. This has given rise to widely differing biogeographic narratives about their evolution. To resolve this problem, we sequenced five introns from 11 species representing all genera of living penguins. Using these data and other available DNA sequences, together with the ages of multiple penguin fossils to calibrate the molecular clock, we estimated the age of the most recent common ancestor of extant penguins to be 20.4 Myr (17.0-23.8 Myr). This time is half of the previous estimates based on molecular sequence data. Our results suggest that most of the major groups of extant penguins diverged 11-16 Ma. This overlaps with the sharp decline in Antarctic temperatures that began approximately 12 Ma, suggesting a possible relationship between climate change and penguin evolution.

  7. The Origins of Transmembrane Ion Channels

    NASA Technical Reports Server (NTRS)

    Pohorille, Andrew; Wilson, Michael A.

    2012-01-01

    Even though membrane proteins that mediate transport of ions and small molecules across cell walls are among the largest and least understood biopolymers in contemporary cells, it is still possible to shed light on their origins and early evolution. The central observation is that transmembrane portions of most ion channels are simply bundles of -helices. By combining results of experimental and computer simulation studies on synthetic models and natural channels, mostly of non-genomic origin, we show that the emergence of -helical channels was protobiologically plausible, and did not require highly specific amino acid sequences. Despite their simple structure, such channels could possess properties that, at the first sight, appear to require markedly larger complexity. Specifically, we explain how the antiamoebin channels, which are made of identical helices, 16 amino acids in length, achieve efficiency comparable to that of highly evolved channels. We further show that antiamoebin channels are extremely flexible, compared to modern, genetically coded channels. On the basis of our results, we propose that channels evolved further towards high structural complexity because they needed to acquire stable rigid structures and mechanisms for precise regulation rather than improve efficiency. In general, even though architectures of membrane proteins are not nearly as diverse as those of water-soluble proteins, they are sufficiently flexible to adapt readily to the functional demands arising during evolution.

  8. Molecular semantics and the origin of life.

    PubMed

    Matsuno, K

    1997-01-01

    The physical origin of life addresses itself to a semantic process on material grounds, in which causation toward contextualization is at work. Physically semantic process of whatever kind is specific in that every material participant is searching and modifying the material context to be fitted in. Fundamental to the physical semantics is the process of measurement proceeding internally among the constituent material participants, whereas the molecular syntax alone as embodied in the form of the quantum-mechanical equation of motion supplemented independently by exogenous boundary conditions cannot cope with the material process underlying the origin. A basic physical attribute of the phenomenon called life is variable duration, in contrast to invariant duration of Galilean inertia. In fact, moleculars replication thought as a harbinger of the phenomenon of life is a concrete form of variable duration and could be established unless internal measurement being instrumental to physically semantic process is forcibly eliminated by some external means. Physical experiments on the onset of molecular replication could become feasible only when external controllability over the intended experiments even at nano-meter scales is abandoned so as to save the room of internal measurement on the part of participating molecules.

  9. Independent origins of diploidy in Metarhizium.

    PubMed

    Kepler, Ryan Michael; Chen, Yuan; Kilcrease, James; Shao, Jonathan; Rehner, Stephen A

    2016-09-12

    In fungi, stable diploid genome arrangements are rare. Here we present evidence from nuclear intergenic DNA sequencing, microsatellite genotyping, and configuration of the mating-type locus to demonstrate two independent origins of persistent diploid genome organization in the Metarhizium majus species complex. Most taxa in the complex are genotypically haploid, with individual isolates consistently displaying a single allele across all nuclear loci, as well as having a single mating-type locus. In contrast, individuals of M. majus and the clade designated here MGT1 are shown to be diploid, based on a consistent finding of heterozygosity and the presence of both MAT1 and MAT2 mating-type loci. In single locus phylogenies, nuclear intergenic alleles of M. majus and MGT1 each form monophyletic groups, indicating that diploidy in both taxa likely originated by the union of conspecific individuals. Sequence divergence in the APN2/MAT1-1-3 and APN2/MAT2-1 intergenic spacers indicate the two MAT loci are physically separated in the genomes of both diploid taxa, although the linkage relationship of the MAT loci to one another is unknown. The presence of both mating genes in a single nucleus suggests these diploid genomes may represent a mating event that failed to complete meiosis. Whether or not these isolates are able to complete the sexual cycle under any conditions and form ascospores remains an open question.

  10. Inversion Concept of the Origin of Life

    NASA Astrophysics Data System (ADS)

    Kompanichenko, V. N.

    2012-06-01

    The essence of the inversion concept of the origin of life can be narrowed down to the following theses: 1) thermodynamic inversion is the key transformation of prebiotic microsystems leading to their transition into primary forms of life; 2) this transformation might occur only in the microsystems oscillating around the bifurcation point under far-from-equilibrium conditions. The transformation consists in the inversion of the balance "free energy contribution / entropy contribution", from negative to positive values. At the inversion moment the microsystem radically reorganizes in accordance with the new negentropy (i.e. biological) way of organization. According to this approach, the origin-of-life process on the early Earth took place in the fluctuating hydrothermal medium. The process occurred in two successive stages: a) spontaneous self-assembly of initial three-dimensional prebiotic microsystems composed mainly of hydrocarbons, lipids and simple amino acids, or their precursors, within the temperature interval of 100-300°C (prebiotic stage); b) non-spontaneous synthesis of sugars, ATP and nucleic acids started at the inversion moment under the temperature 70-100°C (biotic stage). Macro- and microfluctuations of thermodynamic and physico-chemical parameters able to sustain this way of chemical conversion have been detected in several contemporary hydrothermal systems. A minimal self-sufficient unit of life on the early Earth was a community of simplest microorganisms (not a separate microorganism).

  11. Developmental origins of the face inversion effect.

    PubMed

    Cashon, Cara H; Holt, Nicholas A

    2015-01-01

    A hallmark of adults' expertise for faces is that they are better at recognizing, discriminating, and processing upright faces compared to inverted faces. We investigate the developmental origins of "the face inversion effect" by reviewing research on infants' perception of upright and inverted faces during the first year of life. We review the effects of inversion on infants' face preference, recognition, processing (holistic and second-order configural), and scanning as well as face-related neural responses. Particular attention is paid to the developmental patterns that emerge within and across these areas of face perception. We conclude that the developmental origins of the inversion effect begin in the first few months of life and grow stronger over the first year, culminating in effects that are commonly thought to indicate adult-like expertise. We posit that by the end of the first year, infants' face-processing system has become specialized to upright faces and a foundation for adults' upright-face expertise has been established. Developmental mechanisms that may facilitate the emergence of this upright-face specialization are discussed, including the roles that physical and social development may play in upright faces' becoming more meaningful to infants during the first year.

  12. Recombinant Origin of the Retrovirus XMRV

    PubMed Central

    Paprotka, Tobias; Delviks-Frankenberry, Krista A.; Cingöz, Oya; Martinez, Anthony; Kung, Hsing-Jien; Tepper, Clifford G.; Hu, Wei-Shau; Fivash, Matthew J.; Coffin, John M.; Pathak, Vinay K.

    2012-01-01

    The retrovirus XMRV (xenotropic murine leukemia virus-related virus) has been detected in human prostate tumors and in blood samples from patients with chronic fatigue syndrome, but these findings have not been replicated. We hypothesized that an understanding of when and how XMRV first arose might help explain the discrepant results. We studied human prostate cancer cell lines CWR22Rv1 and CWR-R1, which produce XMRV virtually identical to the viruses recently found in patient samples, as well as their progenitor human prostate tumor xenograft (CWR22) that had been passaged in mice. We detected XMRV infection in the two cell lines and in the later passage xenografts, but not in the early passages. Importantly, we found that the host mice contained two proviruses, PreXMRV-1 and PreXMRV-2, which share 99.92% identity with XMRV over >3.2-kb stretches of their genomes. We conclude that XMRV was not present in the original CWR22 tumor but was generated by recombination of two proviruses during tumor passaging in mice. The probability that an identical recombinant was generated independently is negligible (~10-12); our results suggest that the association of XMRV with human disease is due to contamination of human samples with virus originating from this recombination event. PMID:21628392

  13. Precambrian origins of the TNFR superfamily.

    PubMed

    Quistad, S D; Traylor-Knowles, N

    2016-01-01

    The evolution of the tumor necrosis factor/tumor necrosis factor receptor superfamily (TNF/TNFR) is complicated and not well understood. To date, most TNFR studies have focused on vertebrate models leaving the role of TNFRs in invertebrates largely unexplored. The evolution of important cellular processes including stress response, apoptosis, development, and inflammation will be better understood by examining the TNF/TNFR superfamily in ancient invertebrate phyla. How widespread is this gene family within the evolutionary tree of life and is there evidence for similar function in invertebrates? A first step is to identify the presence or absence of these genes within basal metazoan taxa using the signature cysteine-rich domain (CRD) of the TNFR superfamily. In this perspective, we will start by examining what is currently known about the function of TNFRs in invertebrates. Then, we will assess the role of TNFRs in apoptosis and explore the origins of the domains found in TNFRs including the death domain (DD) and CRD. Finally, we will examine the phylogenetic relationship between TNFRs containing DDs identified to date. From these data, we propose a model for a Precambrian origin of TNFRs and their functional role in apoptosis.

  14. Origins of the southeastern Australian vegetation.

    PubMed Central

    Hill, Robert S

    2004-01-01

    Australia is an ancient continent with an interesting geological history that includes a recent major shift in its position, both globally and compared with neighbouring land masses. This has led to a great deal of confusion over many years about the origins of the Australian biomes. The plant fossil record is now clarifying this, and it is clear that the ancient Gondwanan rainforests that covered Australia while it was still part of that supercontinent contained many of the elements of the modern vegetation. However, major climatic sifting, along with responses to other factors, including soil nutrient levels, disturbance regimes, atmospheric CO2 levels, fire frequency and intensity, glaciations and the arrival of humans, have had profound impacts on the Australian vegetation, which today reflects the sum of all these factors and more. The origins of Australian vegetation and its present-day management cannot be properly understood without an appreciation of this vast history, and the fossil record has a vital role to play in maintaining the health of this continent's vegetation into the future. PMID:15519971

  15. The origin of the galaxy color bimodality

    NASA Astrophysics Data System (ADS)

    Aragón-Calvo, M. A.; Neyrinck, Mark C.; Silk, Joseph

    2016-10-01

    The star formation history of galaxies is a complex process usually considered to be stochastic in nature, for which we can only give average descriptions such as the color-density relation. In this work we follow star-forming gas particles in a hydrodynamical N-body simulation back in time in order to study their initial spatial configuration. By keeping record of the time when a gas particle started forming stars we can produce Lagrangian gas-star isochrone surfaces delineating the surfaces of accreting gas that begin producing stars at different times. These surfaces form a complex a network of filaments in Eulerian space from which galaxies accrete cold gas. Lagrangian accretion surfaces are closely packed inside dense regions, intersecting each other, and as a result galaxies inside proto-clusters stop accreting gas early, naturally explaining the color dependence on density. The process described here has a purely gravitational / geometrical origin, arguably operating at a more fundamental level than complex processes such as AGN and supernovae, and providing a conceptual origin for the color-density relation.

  16. Inversion concept of the origin of life.

    PubMed

    Kompanichenko, V N

    2012-06-01

    The essence of the inversion concept of the origin of life can be narrowed down to the following theses: 1) thermodynamic inversion is the key transformation of prebiotic microsystems leading to their transition into primary forms of life; 2) this transformation might occur only in the microsystems oscillating around the bifurcation point under far-from-equilibrium conditions. The transformation consists in the inversion of the balance "free energy contribution / entropy contribution", from negative to positive values. At the inversion moment the microsystem radically reorganizes in accordance with the new negentropy (i.e. biological) way of organization. According to this approach, the origin-of-life process on the early Earth took place in the fluctuating hydrothermal medium. The process occurred in two successive stages: a) spontaneous self-assembly of initial three-dimensional prebiotic microsystems composed mainly of hydrocarbons, lipids and simple amino acids, or their precursors, within the temperature interval of 100-300°C (prebiotic stage); b) non-spontaneous synthesis of sugars, ATP and nucleic acids started at the inversion moment under the temperature 70-100°C (biotic stage). Macro- and microfluctuations of thermodynamic and physico-chemical parameters able to sustain this way of chemical conversion have been detected in several contemporary hydrothermal systems. A minimal self-sufficient unit of life on the early Earth was a community of simplest microorganisms (not a separate microorganism).

  17. Original and creative stereoscopic film making

    NASA Astrophysics Data System (ADS)

    Criado, Enrique

    2008-02-01

    The stereoscopic cinema has become, once again, a hot topic in the film production. For filmmakers to be successful in this field, a technical background in the principles of binocular perception and how our brain interprets the incoming data from our eyes, are fundamental. It is also paramount for a stereoscopic production to adhere certain rules for comfort and safety. There is an immense variety of options in the art of standard "flat" photography, and the possibilities only can be multiply with the stereo. The stereoscopic imaging has its own unique areas for subjective, original and creative control that allow an incredible range of possible combinations by working inside the standards, and in some cases on the boundaries of the basic stereo rules. The stereoscopic imaging can be approached in a "flat" manner, like channeling sound through an audio equalizer with all the bands at the same level. It can provide a realistic perception, which in many cases can be sufficient, thanks to the rock-solid viewing inherent to the stereoscopic image, but there are many more possibilities. This document describes some of the basic operating parameters and concepts for stereoscopic imaging, but it also offers ideas for a creative process based on the variation and combination of these basic parameters, which can lead into a truly innovative and original viewing experience.

  18. Probing the evolutionary origins of music perception.

    PubMed

    McDermott, Josh; Hauser, Marc D

    2005-12-01

    Empirical data have recently begun to inform debates on the evolutionary origins of music. In this paper we discuss some of our recent findings and related theoretical issues. We claim that theories of the origins of music will be usefully constrained if we can determine which aspects of music perception are innate, and, of those, which are uniquely human and specific to music. Comparative research in nonhuman animals, particularly nonhuman primates, is thus critical to the debate. In this paper we focus on the preferences that characterize most humans' experience of music, testing whether similar preferences exist in nonhuman primates. Our research suggests that many rudimentary acoustic preferences, such as those for consonant over dissonant intervals, may be unique to humans. If these preferences prove to be innate in humans, they may be candidates for music-specific adaptations. To establish whether such preferences are innate in humans, one important avenue for future research will be the collection of data from different cultures. This may be facilitated by studies conducted over the internet.

  19. Tracing the origin of Arctic driftwood

    NASA Astrophysics Data System (ADS)

    Hellmann, Lena; Tegel, Willy; Eggertsson, Ã.`Lafur; Schweingruber, Fritz Hans; Blanchette, Robert; Kirdyanov, Alexander; GäRtner, Holger; Büntgen, Ulf

    2013-03-01

    Arctic environments, where surface temperatures increase and sea ice cover and permafrost depth decrease, are very sensitive to even slight climatic variations. Placing recent environmental change of the high-northern latitudes in a long-term context is, however, complicated by too short meteorological observations and too few proxy records. Driftwood may represent a unique cross-disciplinary archive at the interface of marine and terrestrial processes. Here, we introduce 1445 driftwood remains from coastal East Greenland and Svalbard. Macroscopy and microscopy were applied for wood anatomical classification; a multi-species subset was used for detecting fungi; and information on boreal vegetation patterns, circumpolar river systems, and ocean current dynamics was reviewed and evaluated. Four conifer (Pinus, Larix, Picea, and Abies) and three deciduous (Populus, Salix, and Betula) genera were differentiated. Species-specific identification also separated Pinus sylvestris and Pinus sibirica, which account for ~40% of all driftwood and predominantly originate from western and central Siberia. Larch and spruce from Siberia or North America represents ~26% and ~18% of all materials, respectively. Fungal colonization caused different levels of driftwood staining and/or decay. Our results demonstrate the importance of combining wood anatomical knowledge with insight on boreal forest composition for successfully tracing the origin of Arctic driftwood. To ultimately reconstruct spatiotemporal variations in ocean currents, and to better quantify postglacial uplift rates, we recommend consideration of dendrochronologically dated material from many more circumpolar sites.

  20. Origin of Dynamical Quantum Non-locality

    NASA Astrophysics Data System (ADS)

    Pachon, Cesar E.; Pachon, Leonardo A.

    2014-03-01

    Non-locality is one of the hallmarks of quantum mechanics and is responsible for paradigmatic features such as entanglement and the Aharonov-Bohm effect. Non-locality comes in two ``flavours'': a kinematic non-locality- arising from the structure of the Hilbert space- and a dynamical non-locality- arising from the quantum equations of motion-. Kinematic non-locality is unable to induce any change in the probability distributions, so that the ``action-at-a-distance'' cannot manifest. Conversely, dynamical non-locality does create explicit changes in probability, though in a ``causality-preserving'' manner. The origin of non-locality of quantum measurements and its relations to the fundamental postulates of quantum mechanics, such as the uncertainty principle, have been only recently elucidated. Here we trace the origin of dynamical non-locality to the superposition principle. This relation allows us to establish and identify how the uncertainty and the superposition principles determine the non-local character of the outcome of a quantum measurement. Being based on group theoretical and path integral formulations, our formulation admits immediate generalizations and extensions to to, e.g., quantum field theory. This work was supported by the Departamento Administrativo de Ciencia, Tecnologia e Innovacion -COLCIENCIAS- of Colombia under the grant number 111556934912.

  1. Dual origin of mouse spleen macrophages

    PubMed Central

    1984-01-01

    The present study concerns the isolation, characterization, origin, and kinetics of spleen macrophages. The spleen was first perfused in situ to remove monocytes from the vascular bed and then dissected and treated with collagenase. The macrophages in the cell suspension thus obtained were characterized morphologically and cytochemically and then quantitated. The spleen cell suspension was incubated for 24 h in Leighton tubes to obtain an enriched glass-adherent population of macrophages for characterization and [3H]thymidine-labeling studies. Almost all of the adhering macrophages were esterase positive, had Fc and C3b receptors, and ingested EIgG and opsonized bacteria. In vitro labeling with [3H]thymidine showed that approximately 5% of the mononuclear phagocytes in the spleen synthesize DNA and must be considered to be dividing cells. The course of the number of labeled monocytes and macrophages after a single injection of [3H]thymidine indicates migration of monocytes into the spleen, where they become macrophages. Calculation of the influx of monocytes into the spleen and of the local production of macrophages by DNA-synthesizing mononuclear phagocytes showed that under steady-state conditions, 55% of the population of spleen macrophages is supplied by monocyte influx and 45% by local production. This means that there is a dual origin of spleen macrophages. The mean turnover time calculated with the value for the efflux of spleen macrophages is 6.0 d. PMID:6491600

  2. Origins and Dynamics of Interplanetary Dust Particles

    NASA Technical Reports Server (NTRS)

    Dermott, Stanley F.

    2005-01-01

    This is a final report for research supported by the National Aeronautics and Space Administration issued through the Office of Space Science Planetary Geology and Geophysics Program, covering all relevant activities during its 3-year period of funding from 02/01/2002 through to 01/31/2005. The ongoing aim of the research supported through this grant, and now through a successor award, is to investigate the origin of interplanetary dust particles (IDPs) and their dynamical and collisional evolution, in order to: (1) understand the provenance of zodiacal cloud particles and their transport from their source regions to the inner solar system; (2) produce detailed models of the zodiacal cloud and its constituent components; (3) determine the origin of the dust particles accreted by the Earth; (4) ascertain the level of temporal variations in the dust environment of the inner solar system and the accretion rate of IDPs by the Earth, and evaluate potential effects on global climate; and to (5) exploit this research as a basis for interpreting the structure observed in exozodiacal clouds that may result from the collisional evolution of planetesimals and the presence of unseen planets.

  3. RNA Relics and Origin of Life

    PubMed Central

    Demongeot, Jacques; Glade, Nicolas; Moreira, Andrés; Vial, Laurent

    2009-01-01

    A number of small RNA sequences, located in different non-coding sequences and highly preserved across the tree of life, have been suggested to be molecular fossils, of ancient (and possibly primordial) origin. On the other hand, recent years have revealed the existence of ubiquitous roles for small RNA sequences in modern organisms, in functions ranging from cell regulation to antiviral activity. We propose that a single thread can be followed from the beginning of life in RNA structures selected only for stability reasons through the RNA relics and up to the current coevolution of RNA sequences; such an understanding would shed light both on the history and on the present development of the RNA machinery and interactions. After presenting the evidence (by comparing their sequences) that points toward a common thread, we discuss a scenario of genome coevolution (with emphasis on viral infectious processes) and finally propose a plan for the reevaluation of the stereochemical theory of the genetic code; we claim that it may still be relevant, and not only for understanding the origin of life, but also for a comprehensive picture of regulation in present-day cells. PMID:20111682

  4. Origins of Solar Systems Workshop: The Origin, Evolution, and Detectability of Short Period Comets

    NASA Technical Reports Server (NTRS)

    Stern, S. Alan

    1993-01-01

    The origin of the short period comets (SPC) (periods less than 200 years), the dynamical formation of their present reservoir(s), the cause and rate of their transport to the inner planetary region where they can be detected, and the magnitude of selection effects in their discovery are important research questions directly coupled to the goals of understanding the origin and evolution of the Solar System. To address these questions in an intensive way, an interdisciplinary, five month long Workshop from Jan. to May 1993 at Southwest Research Institute (SwRI) in San Antonio was convened. The goal of this Workshop was to advance the state of understanding about the origins, dynamical evolution, and present location of short period comets and their reservoir(s).

  5. Origins of geothermal gases at Yellowstone

    NASA Astrophysics Data System (ADS)

    Lowenstern, Jacob B.; Bergfeld, Deborah; Evans, William C.; Hunt, Andrew G.

    2015-09-01

    Gas emissions at the Yellowstone Plateau Volcanic Field (YPVF) reflect open-system mixing of gas species originating from diverse rock types, magmas, and crustal fluids, all combined in varying proportions at different thermal areas. Gases are not necessarily in chemical equilibrium with the waters through which they vent, especially in acid sulfate terrain where bubbles stream through stagnant acid water. Gases in adjacent thermal areas often can be differentiated by isotopic and gas ratios, and cannot be tied to one another solely by shallow processes such as boiling-induced fractionation of a parent liquid. Instead, they inherit unique gas ratios (e.g., CH4/He) from the dominant rock reservoirs where they originate, some of which underlie the Quaternary volcanic rocks. Steam/gas ratios (essentially H2O/CO2) of Yellowstone fumaroles correlate with Ar/He and N2/CO2, strongly suggesting that H2O/CO2 is controlled by addition of steam boiled from water rich in atmospheric gases. Moreover, H2O/CO2 varies systematically with geographic location, such that boiling is more enhanced in some areas than others. The δ13C and 3He/CO2 of gases reflect a dominant mantle origin for CO2 in Yellowstone gas. The mantle signature is most evident at Mud Volcano, which hosts gases with the lowest H2O/CO2, lowest CH4 concentrations and highest He isotope ratios (~ 16Ra), consistent with either a young subsurface intrusion or less input of crustal and meteoric gas than any other location at Yellowstone. Across the YPVF, He isotope ratios (3He/4He) inversely vary with He concentrations, and reflect varied amounts of long-stored, radiogenic He added to the magmatic endmember within the crust. Similarly, addition of CH4 from organic-rich sediments is common in the eastern thermal areas at Yellowstone. Overall, Yellowstone gases reflect addition of deep, high-temperature magmatic gas (CO2-rich), lower-temperatures crustal gases (4He- and CH4-bearing), and those gases (N2, Ne, Ar) added

  6. Formamide and the origin of life

    NASA Astrophysics Data System (ADS)

    Saladino, Raffaele; Crestini, Claudia; Pino, Samanta; Costanzo, Giovanna; Di Mauro, Ernesto

    2012-03-01

    The complexity of life boils down to the definition: “self-sustained chemical system capable of undergoing Darwinian evolution” (Joyce, 1994) [1]. The term “self-sustained” implies a set of chemical reactions capable of harnessing energy from the environment, using it to carry out programmed anabolic and catabolic functions. We briefly present our opinion on the general validity of this definition. Running anabolic and catabolic functions entails complex chemical information whose stability, reproducibility and evolution constitute the core of what is dubbed genetics. Life as-we-know-it is made of the intimate interaction of metabolism and genetics, both built around the chemistry of the most common elements of the Universe (hydrogen, oxygen, nitrogen, carbon). Other elements like phosphorus and sulphur play important but ancillary and potentially replaceable roles. The reproducible interaction of metabolic and genetic cycles results in the hypercycles of organization and de-organization of chemical information that we consider living entities. In order to approach the problem of the origin of life it is therefore reasonable to start from the assumption that both metabolism and genetics had a common origin, shared a common chemical frame, were embedded in physical-chemical conditions favourable for the onset of both. The most abundant three-atoms organic compound in interstellar environment is hydrogen cyanide HCN, the most abundant three-atoms inorganic compound is water H2O. The combination of the two results in the formation of formamide H2NCOH. We have explored the chemistry of formamide in conditions compatible with the synthesis and the stability of compounds of potential pre-genetic and pre-metabolic interest. We discuss evidence showing (i) that all the compounds necessary for the build-up of nucleic acids are easily obtained abiotically, (ii) that essentially all the steps leading to the spontaneous generation of RNA are abiotically possible, (iii

  7. Origins of Protein Functions in Cells

    NASA Technical Reports Server (NTRS)

    Seelig, Burchard; Pohorille, Andrzej

    2011-01-01

    In modern organisms proteins perform a majority of cellular functions, such as chemical catalysis, energy transduction and transport of material across cell walls. Although great strides have been made towards understanding protein evolution, a meaningful extrapolation from contemporary proteins to their earliest ancestors is virtually impossible. In an alternative approach, the origin of water-soluble proteins was probed through the synthesis and in vitro evolution of very large libraries of random amino acid sequences. In combination with computer modeling and simulations, these experiments allow us to address a number of fundamental questions about the origins of proteins. Can functionality emerge from random sequences of proteins? How did the initial repertoire of functional proteins diversify to facilitate new functions? Did this diversification proceed primarily through drawing novel functionalities from random sequences or through evolution of already existing proto-enzymes? Did protein evolution start from a pool of proteins defined by a frozen accident and other collections of proteins could start a different evolutionary pathway? Although we do not have definitive answers to these questions yet, important clues have been uncovered. In one example (Keefe and Szostak, 2001), novel ATP binding proteins were identified that appear to be unrelated in both sequence and structure to any known ATP binding proteins. One of these proteins was subsequently redesigned computationally to bind GTP through introducing several mutations that introduce targeted structural changes to the protein, improve its binding to guanine and prevent water from accessing the active center. This study facilitates further investigations of individual evolutionary steps that lead to a change of function in primordial proteins. In a second study (Seelig and Szostak, 2007), novel enzymes were generated that can join two pieces of RNA in a reaction for which no natural enzymes are known

  8. Origin and thermal evolution of icy satellites

    NASA Astrophysics Data System (ADS)

    Coradini, Angioletta; Federico, Costanzo; Forni, Olivier; Magni, Gianfranco

    1995-07-01

    The paper reviews the problem of formation and evolution of the so-called “regular satellites “ of the giant planets, and it consists of two parts: the first describes the possible origin of the satellites, the second studies their evolution, attempting to stress the relations of the present status of the satellites with their evolutionary history. The formation of regular satellite systems around giant planets is probably related to the formation of the central planet. Some characteristics of regular satellite systems are quite similar, and suggest a common origin in a disk present around the central body. This disk can originate through different mechanisms which we will describe, paying attention to the so-called “accretion disk” model, in which the satellite-forming material is captured. The disk phase links the formation of the primary body with the formation of satellites. The subsequent stages of the disk's evolution can lead first to the formation of intermediate size bodies, and through the collisional evolution of these bodies, to the birth of satellite “embryos” able to gravitationally capture smaller bodies. Given the scenario in which icy satellites may be formed by homogeneous accretion of planetesimals made of a mixtures of ice and silicates, if no melting occurs during accretion, the satellites have a homogeneous ice-rock composition. For the smaller satellites this homogeneous structure should not be substantially modified; only sporadic local events, such as large impacts, can modify the surface structure of the smaller satellites. For the larger satellites, if some degree of melting appears during accretion, a differentiation of the silicate part occurs, the amount of differentiation and hence the core size depending on the fraction of gravitational potential energy retained during the accumulation process. Melting and differentiation soon after the accretion, for the larger satellites, could also depend on the convective evolution in

  9. Formamide and the origin of life.

    PubMed

    Saladino, Raffaele; Crestini, Claudia; Pino, Samanta; Costanzo, Giovanna; Di Mauro, Ernesto

    2012-03-01

    The complexity of life boils down to the definition: "self-sustained chemical system capable of undergoing Darwinian evolution" (Joyce, 1994) [1]. The term "self-sustained" implies a set of chemical reactions capable of harnessing energy from the environment, using it to carry out programmed anabolic and catabolic functions. We briefly present our opinion on the general validity of this definition. Running anabolic and catabolic functions entails complex chemical information whose stability, reproducibility and evolution constitute the core of what is dubbed genetics. Life as-we-know-it is made of the intimate interaction of metabolism and genetics, both built around the chemistry of the most common elements of the Universe (hydrogen, oxygen, nitrogen, carbon). Other elements like phosphorus and sulphur play important but ancillary and potentially replaceable roles. The reproducible interaction of metabolic and genetic cycles results in the hypercycles of organization and de-organization of chemical information that we consider living entities. In order to approach the problem of the origin of life it is therefore reasonable to start from the assumption that both metabolism and genetics had a common origin, shared a common chemical frame, were embedded in physical-chemical conditions favourable for the onset of both. The most abundant three-atoms organic compound in interstellar environment is hydrogen cyanide HCN, the most abundant three-atoms inorganic compound is water H(2)O. The combination of the two results in the formation of formamide H(2)NCOH. We have explored the chemistry of formamide in conditions compatible with the synthesis and the stability of compounds of potential pre-genetic and pre-metabolic interest. We discuss evidence showing (i) that all the compounds necessary for the build-up of nucleic acids are easily obtained abiotically, (ii) that essentially all the steps leading to the spontaneous generation of RNA are abiotically possible, (iii

  10. Origin and Spatiotemporal Control of Cuspate Forelands

    NASA Astrophysics Data System (ADS)

    McNinch, J. E.

    2006-12-01

    Cuspate shoreline forms are ubiquitous throughout shorelines of the world and span a wide range in size from sub-meter to 102 kilometers; in grain size from fine to coarse; and in energetic settings from small lakes and lagoons to open ocean beaches with virtually unlimited fetch. Cuspate forelands, with wavelengths ranging from 1-120 km, are found worldwide and are the largest of the rhythmic coastal forms. The origin of cuspate forelands has been debated for well over a century but no theory has emerged that fully explains both the origin and the processes controlling the size and time necessary for development. Despite this uncertainty of spatiotemporal controls, large-scale rhythmic morphology of cuspate forelands strongly suggests that scaling and linkages between physical and sedimentary processes may span many orders of magnitude. The same hydrodynamic forces driving sediment transport at the granular scale, such as wave orbital motion and mean currents, likely play a role in shaping the much larger cuspate shorelines. A survey of passive margin, microtidal shorelines from the US and select locations around the world reveals that cuspate forelands are only found in regions where the predominant wind direction is shore-parallel. Modeling and observations of waves, currents, and sediment accumulation from Cape Lookout, North Carolina indicate that water and sediment are transported well seaward of cuspate foreland promontories by wind-driven and tidal residual currents leading to: 1) the rapid growth of spits and sub-aqueous shoals, 2) elimination of sediment exchange between adjacent littoral cells, and 3) control of the wave diffraction point around the promontories. These results and earlier modeling work related to high-angle waves suggest that wind leads to feedback between waves, currents, and promontory-shoal bathymetry and ultimately defines the size and development time of cuspate forelands. Lastly, a linear relationship between the size of cuspate

  11. Origin, dispersal, cultivation and variation of rice.

    PubMed

    Khush, G S

    1997-09-01

    There are two cultivated and twenty-one wild species of genus Oryza. O. sativa, the Asian cultivated rice is grown all over the world. The African cultivated rice, O. glaberrima is grown on a small scale in West Africa. The genus Oryza probably originated about 130 million years ago in Gondwanaland and different species got distributed into different continents with the breakup of Gondwanaland. The cultivated species originated from a common ancestor with AA genome. Perennial and annual ancestors of O. sativa are O. rufipogon and O. nivara and those of O. glaberrima are O. longistaminata, O. breviligulata and O. glaberrima probably domesticated in Niger river delta. Varieties of O. sativa are classified into six groups on the basis of genetic affinity. Widely known indica rices correspond to group I and japonicas to group VI. The so called javanica rices also belong to group VI and are designated as tropical japonicas in contrast to temperate japonicas grown in temperate climate. Indica and japonica rices had a polyphyletic origin. Indicas were probably domesticated in the foothills of Himalayas in Eastern India and japonicas somewhere in South China. The indica rices dispersed throughout the tropics and subtropics from India. The japonica rices moved northward from South China and became the temperate ecotype. They also moved southward to Southeast Asia and from there to West Africa and Brazil and became tropical ecotype. Rice is now grown between 55 degrees N and 36 degrees S latitudes. It is grown under diverse growing conditions such as irrigated, rainfed lowland, rainfed upland and floodprone ecosystems. Human selection and adaptation to diverse environments has resulted in numerous cultivars. It is estimated that about 120,000 varieties of rice exist in the world. After the establishment of International Rice Research Institute in 1960, rice varietal improvement was intensified and high yielding varieties were developed. These varieties are now planted to 70

  12. Origins of geothermal gases at Yellowstone

    USGS Publications Warehouse

    Lowenstern, Jacob B.; Bergfeld, Deborah; Evans, William C.; Hunt, Andrew G.

    2015-01-01

    Gas emissions at the Yellowstone Plateau Volcanic Field (YPVF) reflect open-system mixing of gas species originating from diverse rock types, magmas, and crustal fluids, all combined in varying proportions at different thermal areas. Gases are not necessarily in chemical equilibrium with the waters through which they vent, especially in acid sulfate terrain where bubbles stream through stagnant acid water. Gases in adjacent thermal areas often can be differentiated by isotopic and gas ratios, and cannot be tied to one another solely by shallow processes such as boiling-induced fractionation of a parent liquid. Instead, they inherit unique gas ratios (e.g., CH4/He) from the dominant rock reservoirs where they originate, some of which underlie the Quaternary volcanic rocks. Steam/gas ratios (essentially H2O/CO2) of Yellowstone fumaroles correlate with Ar/He and N2/CO2, strongly suggesting that H2O/CO2 is controlled by addition of steam boiled from water rich in atmospheric gases. Moreover, H2O/CO2 varies systematically with geographic location, such that boiling is more enhanced in some areas than others. The δ13C and 3He/CO2 of gases reflect a dominant mantle origin for CO2 in Yellowstone gas. The mantle signature is most evident at Mud Volcano, which hosts gases with the lowest H2O/CO2, lowest CH4 concentrations and highest He isotope ratios (~16Ra), consistent with either a young subsurface intrusion or less input of crustal and meteoric gas than any other location at Yellowstone. Across the YPVF, He isotope ratios (3He/4He) inversely vary with He concentrations, and reflect varied amounts of long- stored, radiogenic He added to the magmatic endmember within the crust. Similarly, addition of CH4 from organic-rich sediments is common in the eastern thermal areas at Yellowstone. Overall, Yellowstone gases reflect addition of deep, high-temperature magmatic gas (CO2-rich), lower-temperatures crustal gases (4He- and CH4-bearing), and those gases (N2, Ne, Ar) added

  13. 13. Photocopy of engineering drawing (original drawing,(original drawing, #MH 10460086, ...

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

    13. Photocopy of engineering drawing (original drawing,(original drawing, #MH 104-600-86, dated October 31, 1995, and drawn by W. Robinson, is located in the Mountain Home Air Force Base Civil Engineering archives. This 1995 drawing is a copy of drawing #MH 104-600-06, dated December 21, 1955, entitled "Repair Exterior Siding Elev. & Exterior Painting. Bldg. 611," also located in the Mountain Home Air Force Base Civil Engineering archives). FAC 611. - Mountain Home Air Force Base, Base Chapel, 350 Willow Street, Cantonment Area, Mountain Home, Elmore County, ID

  14. The Genetic Origins of the Andaman Islanders

    PubMed Central

    Endicott, Phillip; Gilbert, M. Thomas P.; Stringer, Chris; Lalueza-Fox, Carles; Willerslev, Eske; Hansen, Anders J.; Cooper, Alan

    2003-01-01

    Mitochondrial sequences were retrieved from museum specimens of the enigmatic Andaman Islanders to analyze their evolutionary history. D-loop and protein-coding data reveal that phenotypic similarities with African pygmoid groups are convergent. Genetic and epigenetic data are interpreted as favoring the long-term isolation of the Andamanese, extensive population substructure, and/or two temporally distinct settlements. An early colonization featured populations bearing mtDNA lineage M2, and this lineage is hypothesized to represent the phylogenetic signal of an early southern movement of humans through Asia. The results demonstrate that Victorian anthropological collections can be used to study extinct, or seriously admixed populations, to provide new data about early human origins. PMID:12478481

  15. Botanical origin of Indian celery seed (fruit).

    PubMed

    Maruyama, Takuro; Abbaskhan, Ahmed; Choudhary, Muhammad Iqbal; Tsuda, Yoshisuke; Goda, Yukihiro; Farille, Michel; Reduron, Jean-Pierre

    2009-07-01

    In the course of our study on the traditional medicines and foodstuffs used in Pakistan, we investigated the origin of Indian celery by using the analysis of the internal transcribed spacer (ITS) sequence of nuclear rDNA and a phytochemical approach. We found that the source plant of the Indian celery containing coumarin derivatives such as seselin (1), bergapten (2) and isopimpinellin (3) was not common celery, Apium graveolens. Our results suggest the source plant is Seseli diffusum even though Indian workers reported that A. graveolens seeds contain the aforementioned compounds. In addition, a market survey of the Indian celery in Pakistan and related countries revealed that the Indian celery seeds in Pakistani markets are mainly composed of three species which have been confused in rural markets.

  16. Origins and challenges of viral dark matter.

    PubMed

    Krishnamurthy, Siddharth R; Wang, David

    2017-02-09

    The accurate classification of viral dark matter - metagenomic sequences that originate from viruses but do not align to any reference virus sequences - is one of the major obstacles in comprehensively defining the virome. Depending on the sample, viral dark matter can make up from anywhere between 40 and 90% of sequences. This review focuses on the specific nature of dark matter as it relates to viral sequences. We identify three factors that contribute to the existence of viral dark matter: the divergence and length of virus sequences, the limitations of alignment based classification, and limited representation of viruses in reference sequence databases. We then discuss current methods that have been developed to at least partially circumvent these limitations and thereby reduce the extent of viral dark matter.

  17. The origin of KREEP. [lunar composition

    NASA Technical Reports Server (NTRS)

    Warren, P. H.

    1979-01-01

    The concept of 'urKREEP' (primeval KREEP), a magma residuum hypothetically produced early in lunar history by fractional distillation of the global magma ocean which hypothetically created the lunar crust, is used to explain the origin of KREEPy lunar rocks. The incompatible-rich last dregs of the magma ocean left their trace in the form of incompatible patterns that show no relative fractionation from site to site on the moon and that, with the exception of minor fractionals in two pristine clasts, are the same in pristine samples as in breccias. The high concentration on the lunar surface of these urKREEP remnants demands a high efficiency in upward transport of the incompatibles. This transport may have been enhanced by urKREEP's presumably low density and by high temperatures produced by radioactive decay in the K-, U-, and Th-rich residuum.

  18. Is there a single origin of life?

    NASA Technical Reports Server (NTRS)

    Soffen, Gerald A.

    1986-01-01

    The emergence of the first life on the earth is now established as an early event, closely related to the evolving earth. Lack of knowledge of the primitive terrestrial conditions contemporary with the evolving prebolic organic chemistry limits reconstruction techniques. The primitive earth's aqueous history is essential to unraveling this problem. Based on current knowledge of other planets of the solar system, no close analog to the early earth can be expected. It is still not known if there was a second origin or if only earth has life. This may depend upon the question of the survival of information-bearing chemical systems in a dynamic or chaotic environment and the chemical protection afforded within such a system. Water is the central molecule of controversy: the blessing and the curse of the chemist. New and novel chemical mechanisms and systems abound.

  19. Hemichordates and the origin of chordates

    NASA Technical Reports Server (NTRS)

    Gerhart, John; Lowe, Christopher; Kirschner, Marc

    2005-01-01

    Hemichordates, the phylum of bilateral animals most closely related to chordates, could reveal the evolutionary origins of chordate traits such as the nerve cord, notochord, gill slits and tail. The anteroposterior maps of gene expression domains for 38 genes of chordate neural patterning are highly similar for hemichordates and chordates, even though hemichordates have a diffuse nerve-net. About 40% of the domains are not present in protostome maps. We propose that this map, the gill slits and the tail date to the deuterostome ancestor. The map of dorsoventral expression domains, centered on a Bmp-Chordin axis, differs between the two groups; hemichordates resemble protostomes more than they do chordates. The dorsoventral axis might have undergone extensive modification in the chordate line, including centralization of the nervous system, segregation of epidermis, derivation of the notochord, and an inversion of organization.

  20. Microscopic origin of volume modulus inflation

    SciTech Connect

    Cicoli, Michele; Muia, Francesco; Pedro, Francisco Gil E-mail: muia@bo.infn.it

    2015-12-01

    High-scale string inflationary models are in well-known tension with low-energy supersymmetry. A promising solution involves models where the inflaton is the volume of the extra dimensions so that the gravitino mass relaxes from large values during inflation to smaller values today. We describe a possible microscopic origin of the scalar potential of volume modulus inflation by exploiting non-perturbative effects, string loop and higher derivative perturbative corrections to the supergravity effective action together with contributions from anti-branes and charged hidden matter fields. We also analyse the relation between the size of the flux superpotential and the position of the late-time minimum and the inflection point around which inflation takes place. We perform a detailed study of the inflationary dynamics for a single modulus and a two moduli case where we also analyse the sensitivity of the cosmological observables on the choice of initial conditions.