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Sample records for colonic transit time

  1. Acute Appendicitis as Complication of Colon Transit Time Study; A Case Report.

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    Ghahramani, Leila; Roshanravan, Reza; Khodaei, Shahin; Rahimi Kazerooni, Salar; Moslemi, Sam

    2015-07-01

    Colon transit time study with radio opaque markers is a simple method for assessment of colon motility disorder in patients with chronic idiopathic constipation. We report a case of acute appendicitis that was induced by impaction of radio opaque markers after colon transit time study. We think that this case report is first significant complication of colon transit time study until now.

  2. Colonic transit time relates to bacterial metabolism and mucosal turnover in the human gut

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Hansen, Lea Benedicte Skov; Bahl, Martin Iain

    transit time and the gut microbial composition and metabolism, we assessed the colonic transit time of 98 subjects using radiopaque markers, and profiled their gut microbiota by16S rRNA gene sequencingand their urine metabolome by ultra performance liquid chromatography mass spectrometry. Based......Little is known about how colonic transit time relates to human colonic metabolism, and its importance for host health, although stool consistency, a proxy for colonic transit time, has recently been negatively associated with gut microbial richness. To address the relationships between colonic...... on correlation analyses,we show that colonic transit time is associated with overall gutmicrobial composition, diversity and metabolism. A relatively prolonged colonic transit time associates with high microbial species richness and a shift in colonic metabolismfrom carbohydrate fermentation to protein...

  3. Colonic transit time is related to bacterial metabolism and mucosal turnover in the human gut

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Hansen, Lea Benedicte Skov; Bahl, Martin Iain

    transit time and the gut microbial composition and metabolism, we assessed the colonic transit time of 98 subjects using radiopaque markers, and profiled their gut microbiota by16S rRNA gene sequencing and their urine metabolome by ultra performance liquid chromatography mass spectrometry. Based......Little is known about how colonic transit time relates to human colonic metabolism, and its importance for host health, although stool consistency, a proxy for colonic transit time, has recently been negatively associated with gut microbial richness. To address the relationships between colonic...... on correlation analyses, we show that colonic transit time is associated with overall gut microbial composition, diversity and metabolism. A relatively prolonged colonic transit time associates with high microbial species richness and a shift in colonic metabolism from carbohydrate fermentation to protein...

  4. Colonic transit time is related to bacterial metabolism and mucosal turnover in the gut

    DEFF Research Database (Denmark)

    Roager, Henrik Munch; Hansen, Lea Benedicte Skov; Bahl, Martin Iain;

    2016-01-01

    Little is known about how colonic transit time relates to human colonic metabolism and its importance for host health, although a firm stool consistency, a proxy for a long colonic transit time, has recently been positively associated with gut microbial richness. Here, we show that colonic transit...... time in humans, assessed using radio-opaque markers, is associated with overall gut microbial composition, diversity and metabolism. We find that a long colonic transit time associates with high microbial richness and is accompanied by a shift in colonic metabolism from carbohydrate fermentation...... to protein catabolism as reflected by higher urinary levels of potentially deleterious protein-derived metabolites. Additionally, shorter colonic transit time correlates with metabolites possibly reflecting increased renewal of the colonic mucosa. Together, this suggests that a high gut microbial richness...

  5. Colon Transit Time in the Iranian Patients with Chronic Constipation

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    "M. Poorafkari

    2005-08-01

    Full Text Available Introduction & Background: There are differences in cultural practices of defecation, diet, and average stool size between countries. On the other hand ROME II criteria tried to allow a unit category for the diagnosis of chronic functional constipation. We de-signed this study to find whether whole gut transit time is in concordance with ROME II criteria. Patients & Methods: From January 2004 to October 2005, we included patients older than 18 years old referred to the radiology ward of Taleghani Hospital for symptom-based definition of constipation pro-posed by an international working team (Rome II definition. None of the patients had responded prop-erly to treatment. Irritable bowel syndrome was ruled out and then conventional colon transit time (CTT test was performed for all of the included patients. Results: A total of 142 patients were enrolled in this study. A hundred and eight patients were women (76 %. Mean age of the patients was 38.9 (SD: 13.8. CTT revealed colonic inertia, and outlet obstruction in 16 (15% and 10 (9.3% patients respectively. Of all patients with abnormal CTT, 21 (80.7% had fewer than three bowel movements per week as their main complaint. Multivariate analysis showed that positive results were more commonly associated with fewer than three bowel movements per week than other symptoms (p value=0.01. Conclusion: Among patients with chronic constipa-tion, objective findings were not in concordance with subjective complaints. Therefore Rome II criteria may overestimate constipation in our population.

  6. Assessment of chronic constipation: colon transit time versus defecography

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    Prokesch, R.W. E-mail: rupert.prokesch@univie.ac.at; Breitenseher, M.J.; Kettenbach, J.; Herbst, F.; Maier, A.; Lechner, G.; Mahieu, P

    1999-12-01

    Objective: The aim of this study was to determine the value of radiological colon transit time (CTT) measurements in relation to defecography (DFG) in chronically constipated patients. Materials and methods: In 30 patients with chronic constipation, total and segmental CTT was determined using radiopaque markers. In all of these patients defecography (DFG) was obtained. The patients were divided into three groups: In group I, 11 patients were classified with idiopathic constipation based on low stool frequency, normal DFG, or absence of symptoms of abnormal defecation. In group II, ten patients with rectal intussusception were diagnosed by DFG. In group III, there were nine patients with rectal prolapse or spastic pelvic floor syndrome, based on results of DFG. Results: Group I, idiopathic constipation (n=11), showed increased total CTT (mean, 93 h) and segmental CTT (right colon, 33 h (36%), left colon, 31 h (33%), rectosigmoid, 29 h (31%)). In group II, intussusception (n=10), patients had normal mean total CTT (54 h) and a relative decrease in rectosigmoid CTT (mean, 13 h (24%)). In group III (n=9), rectal prolapse (n=5) or spastic pelvic floor syndrome (n=4), patients showed elevated total (mean, 167 h) and rectosigmoidal CTT (mean, 95 h (57%)). Mean total CTT was significantly different between groups I and II and between groups II and III, and mean rectosigmoidal CTT was significantly different between all three groups (P<0.05). Conclusion: The use of total and rectosigmoidal CTT helps to identify the underlying pathophysiology of chronic constipation. Furthermore CTT helps to identify patients, who may benefit from DFG.

  7. Colonic transit time in patient with slow-transit constipation: Comparison of radiopaque markers and barium suspension method

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    Xu Huimin [Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University, No. 8 Gongtina Lu, Chaoyang District, Beijing 100020 (China); Department of General Surgery, Weifang People' s Hospital, ShanDong Province 261041 (China); Han Jiagang [Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University, No. 8 Gongtina Lu, Chaoyang District, Beijing 100020 (China); Na Ying [Department of Medical Imaging, Weifang People' s Hospital, ShanDong Province 261041 (China); Zhao Bo; Ma Huachong [Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University, No. 8 Gongtina Lu, Chaoyang District, Beijing 100020 (China); Wang Zhenjun, E-mail: wang3zj@sohu.com [Department of General Surgery, Beijing Chaoyang Hospital, Capital Medical University, No. 8 Gongtina Lu, Chaoyang District, Beijing 100020 (China)

    2011-08-15

    Background: Colonic transit study provides valuable information before surgical treatment is considered for patient with constipation. The radiopaque markers method is the most common way for evaluating colon transit time. The aim of this study is to compare the barium suspension with the radiopaque makers to assess the colonic mobility in patient with constipation. Methods: Colonic transit time was measured in 11 female patients with slow-transit constipation using both radiopaque markers and barium suspension method. In radiopaque markers method, the patient ingested 20 markers on the first day, and an abdominal radiograph was performed every 24 h until 80% markers were excreted. In barium suspension method, the patient swallowed up to 50 ml of 200% (w/v) barium meal. The abdominal radiographs were taken at the same time point as the former. Results: The total or segmental colonic transit time were obviously prolonged in all patients. Segmental transits time spent in the right colon, left colon and rectosigmoid for radiopaque markers and barium suspension method was, respectively, 30 {+-} 6 h and 34 {+-} 7 h; 38 {+-} 9 h and 32 {+-} 6 h; 40 {+-} 8 h and 38 {+-} 10 h. In the radiopaque markers method, total colonic transit time was 108 {+-} 14 h and it was 103 {+-} 13 h in the barium suspension method (P > 0.05). Conclusion: The barium suspension and radiopaque markers gave the similar results for colonic transit time. The barium suspension was a simple and cheap method for evaluating the colonic mobility.

  8. Total and segmental colonic transit time in constipated patients with Chagas? disease without megaesophagus or megacolon

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    Santos S.L.

    2000-01-01

    Full Text Available Manometric and pharmacological tests have shown that motor abnormalities may occur in the non-dilated colons of chagasic patients. In order to investigate the presence of abnormalities of colonic function in constipated patients with Chagas? disease (ChC without megaesophagus or megacolon, studies of total and segmental colonic transit time with radiopaque markers were performed on 15 ChC patients, 27 healthy volunteers and 17 patients with idiopathic constipation (IC. The values obtained for the control group were similar to those reported in the literature (total colonic time: 34.1 ± 15.6 h; right colon: 9.9 ± 7.3 h; left colon: 10.8 ± 10 h, and rectosigmoid: 12.6 ± 9.9 h. Colonic transit time data permitted us to divide both IC and ChC patients into groups with normal transit and those with slow colonic transit. Colonic inertia was detected in 41% of IC patients and in 13% of ChC patients; left colon isolated stasis (hindgut dysfunction was detected in 12% of IC patients and 7% of ChC patients, and outlet obstruction was detected in 6% of IC patients and 7% of ChC patients. There were no significant differences in total or segmental colonic transit times between slow transit IC and slow transit ChC patients. In conclusion, an impairment of colonic motility was detected in about 30% of constipated patients with Chagas? disease without megaesophagus or megacolon. This subgroup of patients presented no distinctive clinical feature or pattern of colonic dysmotility when compared to patients with slow transit idiopathic constipation.

  9. Total and Segmental Colon Transit Time Study in Functional Constipation: Comparison With Healthy Subjects

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    Bhate, Prasad A.; Patel, Jatin A.; Parikh, Pathik; Ingle, Meghraj A.; Phadke, Anniruddha; Sawant, Prabha D.

    2015-01-01

    Background Constipation is a common problem worldwide. Constipation can be primary or secondary. Primary constipation is subdivided in slow transit constipation, normal transit constipation, and dyssynergic defecation. Colon transit time (CTT) is the most basic and primary tool in evaluating disorders of colonic motility. CTT helps to differentiate between types of constipation and plan the treatment. Methods Fifty functional constipation patients and 25 healthy controls were asked to ingest four gelatin capsules (each containing five radio-opaque markers) at 0, 12 and 24 hours. An abdominal X-ray was taken at 36 hours. Total or segmental CTT was measured after calculating the number of markers remaining in each segment at 36 hours on abdominal X-ray. Results Mean CTT in healthy controls in our study was 15.4 hours which is shorter than western population. Total CTT is significantly higher in constipation group (23 hours) compared to healthy subjects (15.4 hours). Transit time in right segment was significantly high in constipation group than healthy population (14.2 vs. 8.3 hours). Total as well as segmental transit times are slightly higher in females as compared to males in both the groups, however not statistically significant. To the best of our knowledge, there are no studies from India that compared the CTTs in functional constipation and healthy controls. Conclusion Radio-opaque marker study for CTT is a simple and reliable technique for evaluation of constipation. Patients with functional constipation have significantly longer CTT than healthy population. Total CTT is much less in this study population compared to west. There is need to establish standards for slow colon transit. PMID:27785288

  10. Radiographic analysis of the effect of dietary fibers on rat colonic transit time

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    Lupton, J.R.; Meacher, M.M. (Texas A M Univ., College Station (USA))

    1988-11-01

    The effect of different fiber sources on colonic transit time was charted using serial radiographs. Sixty male Sprague-Dawley rats, 10 rats per group, were provided with either a fiber-free control diet or the control diet uniformly diluted to provide 8% dietary fiber from guar, pectin, cellulose, wheat bran, or oat bran. At surgery, radiopaque markers were inserted at defined distances in the mesentary closest to the large bowel. Three weeks postsurgery, the animals were intubated with 0.5 ml of a radiopaque marker, and radiographs were taken at 15-min intervals. Of the two poorly fermented fibers, cellulose was as slow as and wheat bran was faster than the fiber-free controls at five out of the six bowel segments measured. The fermentable fibers (pectin, guar, and oat bran) were fast through some bowel segments and slow through others. This study provides in vivo data on colonic transit time and shows that neither 24-h fecal weight nor total transit time is a good predictor of the rate of transit through particular gut segments.

  11. Comparison of colonic transit time findings between spastic pelvic floor syndrome and normal on defecogram

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    Kim, Seung Kwon; Choi, Sang Hee; Chung, Il Gyu; Lim, Hyo Keun; Choo, Sung Wook; Rhee, Poong Lyul [Samsung Medical Center, Seoul (Korea, Republic of)

    1998-05-01

    The purpose of this study is to evaluate colonic transit time (CTT) in patients with spastic pelvic floor syndrome (SPFS) diagnosed by defecography and compare findings with those of patients with normal defecography. Over a recent 15-month period, 140 patients underwent both defecography and CTT test because of chronic idiopathic constipation. Of these, 54 with SPFS diagnosed by defecography and 49 controls with normal defecography were included in our study. CTT test involved the radiopaque marker method. Subjects ingested 24 markers at 9:00 Am on three consecutive days and a plain film of the abdomen was obtained on day 4. We calculated total and segmental CTT test findings in the two groups. Delayed total CTT was found in 35% of patients (19/54) with SPFS. Segmental CTT in the right, left and rectosigmoid colon was delayed in 31 % of patients (15/49) with SPFS. Segmental CTT in the right, left and rectosigmoid colon was delayed in 19 % (10/54), 44 % (24/54), and 31 % of cases (17/54), respectively. Total CTT was delayed in 31 % of patients (15/49) with normal defecography. In this group, segmental CTT in the left colon was delayed in 39 % of cases. There was no significant difference in CTT findings between the SPFS and normal groups on defecogram. (author). 18 refs., 2 tabs., 5 figs.

  12. Usefulness of colon transit time and defecography in patients with chronic constipation

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    Park, Kyoung Seuk; Chung, Jae Joon; Kim, Myung Hyun; Park, Su Mi; Yang, Hee Chul [NHIC Ilsan Hospital, Ilsan (Korea, Republic of)

    2006-05-15

    We wanted to evaluate whether both the colonic transit time (CTT) and defecography are necessary for diagnosing constipated patients, and we also wanted to assess the defecographic findings of patients with outlet obstruction on CTT. Over the recent 3 years, 26 patients (21 women and 5 men, mean age: 59 years) underwent both CTT and defecography because of their chronic constipations or defecation difficulty. The mean interval between the 2 studies was 48 days. Colonoscopy, barium enema and manometry were performed in 22, 8 and all the patients, respectively. On CTT, 13 patients (50.0%) were normal and 13 patients (50.0%) were abnormal; the abnormal results were composed of outlet obstruction (n = 8, 30.8%), outlet obstruction and colon inertia (n = 2, 7.7%), colon inertia (n = 2, 7.7%), and outlet obstruction and hindgut dysfunction (n = 1, 3.8%). On defecography, 6 patients (23.1%) were normal and 20 patients (76.9%) were abnormal; the results were composed of rectocele (n = 8, 30.7%), rectocele and perineal descent syndrome (PDS; n = 4, 15.4%), PDS and rectal intussusception (n = 3, 11.5%), spastic pelvic floor syndrome (SPFS; n = 3, 11.5%), rectocele and SPFS (n = 1, 3.8%), and rectal intussusception (n = 1, 3.8%). Of the 11 patients with outlet obstruction on CTT, rectocele (n = 4, 36.4%), SPFS (n = 1, 9.1%), rectocele and PDS (n = 1, 9.1%), and PDS and rectal intussusception (n = 1, 9.1%) were demonstrated on defecography, except for the 4 normal cases. Both CTT and defecography were necessary for diagnosing the patients with chronic constipation in compensation, and 63.6% of the patients with pelvic outlet obstruction showed an abnormal pelvic defecation function.

  13. Semi-automatic detection of Gd-DTPA-saline filled capsules for colonic transit time assessment in MRI

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    Harrer, Christian; Kirchhoff, Sonja; Keil, Andreas; Kirchhoff, Chlodwig; Mussack, Thomas; Lienemann, Andreas; Reiser, Maximilian; Navab, Nassir

    2008-03-01

    Functional gastrointestinal disorders result in a significant number of consultations in primary care facilities. Chronic constipation and diarrhea are regarded as two of the most common diseases affecting between 2% and 27% of the population in western countries 1-3. Defecatory disorders are most commonly due to dysfunction of the pelvic floor or the anal sphincter. Although an exact differentiation of these pathologies is essential for adequate therapy, diagnosis is still only based on a clinical evaluation1. Regarding quantification of constipation only the ingestion of radio-opaque markers or radioactive isotopes and the consecutive assessment of colonic transit time using X-ray or scintigraphy, respectively, has been feasible in clinical settings 4-8. However, these approaches have several drawbacks such as involving rather inconvenient, time consuming examinations and exposing the patient to ionizing radiation. Therefore, conventional assessment of colonic transit time has not been widely used. Most recently a new technique for the assessment of colonic transit time using MRI and MR-contrast media filled capsules has been introduced 9. However, due to numerous examination dates per patient and corresponding datasets with many images, the evaluation of the image data is relatively time-consuming. The aim of our study was to develop a computer tool to facilitate the detection of the capsules in MRI datasets and thus to shorten the evaluation time. We present a semi-automatic tool which provides an intensity, size 10, and shape-based 11,12 detection of ingested Gd-DTPA-saline filled capsules. After an automatic pre-classification, radiologists may easily correct the results using the application-specific user interface, therefore decreasing the evaluation time significantly.

  14. Value of Abdominal Radiography, Colonic Transit Time, and Rectal Ultrasound Scanning in the Diagnosis of Idiopathic Constipation in Children : A Systematic Review

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    Berger, Marjolein Y.; Tabbers, Merit M.; Kurver, Miranda J.; Boluyt, Nicole; Benninga, Marc A.

    2012-01-01

    Objective To perform a systematic review evaluating the value of abdominal radiography, colonic transit time (CTT), and rectal ultrasound scanning in the diagnosis of idiopathic constipation in children. Study design Eligible studies were those assessing diagnostic accuracy of abdominal radiography,

  15. THE COLONIC TRANSIT TEST IN THE ASSESSMENT OF CHRONIC CONSTIPATION

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    In order to assess colonic motility of chronic constipation, colonic transit test was carried out in 34 patients with chronic constipation and in 20 healthy subjects. 20 radiopaque markers are ingested at 8 am before the day test, and plain abdominal films were obtained at 24 h, 48 h and 72 h. The normal value of colonic transit test was 16(80%), or more markers passed after 72 h. By means of transit time study, 34 constipated patients were classified into 2 groups: 12 normal transit patients and 22 slow transit patients. There was no difference in colonic transit time between normal transit patients and controls (P>0.05). Patients with slow transit had more markers left in right colon, left colon and rectosigmoid colon at 48 h (P<0.01, respectively) and 72 h (P<0.01, respectively). According to the transit index, 22 slow transit patients were divided into 3 types: 10 cases colonic stasis, 8 cases outlet obstruction and 4 cases colorectal stasis. The study suggests that chronic constipated patients have abnormalbilities of colonic transit.

  16. Correlation between Colon Transit Time Test Value and Initial Maintenance Dose of Laxative in Children with Chronic Functional Constipation

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    Kim, Mock Ryeon; Park, Hye Won; Son, Jae Sung; Lee, Ran

    2016-01-01

    Purpose To evaluate the correlation between colon transit time (CTT) test value and initial maintenance dose of polyethylene glycol (PEG) 4000 or lactulose. Methods Of 415 children with chronic functional constipation, 190 were enrolled based on exclusion criteria using the CTT test, defecation diary, and clinical chart. The CTT test was performed with prior disimpaction. The laxative dose for maintenance was determined on the basis of the defecation diary and clinical chart. The Shapiro-Wilk test and Pearson's and Spearman's correlations were used for statistical analysis. Results The overall group median value and interquartile range of the CTT test was 43.8 (31.8) hours. The average PEG 4000 dose for maintenance in the overall group was 0.68±0.18 g/kg/d; according to age, the dose was 0.73±0.16 g/kg/d (<8 years), 0.53±0.12 g/kg/d (8 to <12 years), and 0.36±0.05 g/kg/d (12 to 15 years). The dose of lactulose was 1.99±0.43 mL/kg/d (<8 years) or 1.26±0.25 mL/kg/d (8 to <12 years). There was no significant correlation between CTT test value and initial dose of laxative, irrespective of the subgroup (encopresis, abnormal CTT test subtype) for either laxative. Even in the largest group (overall, n=109, younger than 8 years and on PEG 4000), the correlation was weak (Pearson's correlation coefficient [R]=0.268, p=0.005). Within the abnormal transit group, subgroup (n=73, younger than 8 years and on PEG 4000) correlation was weak (R=0.267, p=0.022). Conclusion CTT test value cannot predict the initial maintenance dose of PEG 4000 or lactulose with linear correlation.

  17. Central neuropeptide Y receptors are involved in 3rd ventricular ghrelin induced alteration of colonic transit time in conscious fed rats

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    Ritter Michael

    2005-02-01

    Full Text Available Abstract Background Feeding related peptides have been shown to be additionally involved in the central autonomic control of gastrointestinal functions. Recent studies have shown that ghrelin, a stomach-derived orexigenic peptide, is involved in the autonomic regulation of GI function besides feeding behavior. Pharmacological evidence indicates that ghrelin effects on food intake are mediated by neuropeptide Y in the central nervous system. Methods In the present study we examine the role of ghrelin in the central autonomic control of GI motility using intracerobroventricular and IP microinjections in a freely moving conscious rat model. Further the hypothesis that a functional relationship between NPY and ghrelin within the CNS exists was addressed. Results ICV injections of ghrelin (0.03 nmol, 0.3 nmol and 3.0 nmol/5 μl and saline controls decreased the colonic transit time up to 43%. IP injections of ghrelin (0.3 nmol – 3.0 nmol kg-1 BW and saline controls decreased colonic transit time dose related. Central administration of the NPY1 receptor antagonist, BIBP-3226, prior to centrally or peripherally administration of ghrelin antagonized the ghrelin induced stimulation of colonic transit. On the contrary ICV-pretreatment with the NPY2 receptor antagonist, BIIE-0246, failed to modulate the ghrelin induced stimulation of colonic motility. Conclusion The results suggest that ghrelin acts in the central nervous system to modulate gastrointestinal motor function utilizing NPY1 receptor dependent mechanisms.

  18. Gastrointestinal pH and Transit Time Profiling in Healthy Volunteers Using the IntelliCap System Confirms Ileo-Colonic Release of ColoPulse Tablets.

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    Jacoba M Maurer

    Full Text Available ColoPulse tablets are an innovative development in the field of oral dosage forms characterized by a distal ileum and colon-specific release. Previous studies in humans showed release in the ileo-colonic region, but the relationship between gastrointestinal pH and release was not experimentally proven in vivo. This information will complete the in vivo release-profile of ColoPulse tablets.Release from ColoPulse tablets was studied in 16 healthy volunteers using the dual label isotope strategy. To determine gastrointestinal pH profiles and transit times the IntelliCap system was used. A ColoPulse tablet containing 13C-urea and an uncoated, immediate release tablet containing 15N2-urea were taken simultaneously followed by a standardized breakfast after three hours. Five minutes after intake of the tablets the IntelliCap capsule was swallowed and pH was measured until excretion in the feces. Breath and urine samples were collected for isotope analysis.Full analysis could be performed in 12 subjects. Median bioavailability of 13C -urea was 82% (95% CI 74-94%, range 61-114%. The median lag time (5% release of 13C was 5:42 h (95% CI 5:18-6:18 h, range 2:36-6:36 h, There was no statistically significant difference between lag time based on isotope signal and colon arrival time (CAT based on pH (median 5:42 vs 5:31 h p = 0.903. In all subjects an intestinal pH value of 7.0 was reached before release of 13C from the ColoPulse tablet occurred.From the combined data from the IntelliCap system and the 13C -isotope signal it can be concluded that release from a ColoPulse tablet in vivo is not related to transit times but occurs in the ileo-colonic region after pH 7.0 is reached. This supports our earlier findings and confirms that the ColoPulse system is a promising delivery system for targeting the distal ileum and colon.ISRCTN Registry 18301880.

  19. Effects of morphine and naloxone on feline colonic transit

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    Krevsky, B.; Libster, B.; Maurer, A.H.; Chase, B.J.; Fisher, R.S.

    1989-01-01

    The effects of endogenous and exogenous opioid substances on feline colonic transit were evaluated using colonic transit scintigraphy. Naloxone accelerated emptying of the cecum and ascending colon, and filling of the transverse colon. Endogenous opioid peptides thus appear to play a significant role in the regulation of colonic transit. At a moderate dose of morphine cecum and ascending colon transit was accelerated, while at a larger dose morphine had no effect. Since naloxone, a relatively nonspecific opioid antagonist, and morphine, a principally mu opioid receptor agonist, both accelerate proximal colonic transit, a decelerating role for at least one of the other opioid receptors is inferred.

  20. Scintigraphic measurement of colonic transit in patients with idiopathic constipation

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    Yoon, K. H.; Kim, C. K. [College of Medicine, Wonkwang Univ., Iksan (Korea, Republic of)

    1999-07-01

    To evaluate usefulness of scintigraphic measurement of total and regional colonic transit in patients with idiopathic constipation. 25 patients who were complained chronic constipation underwent scintigraphic measurement of the total and regional colon transit. Of them 10 patients were diagnosed as idiopathic constipation, none of whom had evidence of abnormal function of the pelvic floor. Ten healthy volunteers were also studied. 67 Gallium-labelled Amberlite resin particles were ingested in a coated capsule with methacrylate that dispersed in the ileocecal region. Images were obtained using a gamma camera at regular intervals for the 2, 4, 8, 24, and 48 hours after the initial counting of the radioactivity in the cecum. We determined the geometric center in four regions of interest in the colon (ascending, transverse, descending, and rectosigmoid). Ten patients with colonic inertia showed significant retention of solid residue in the ascending and transverse colon over a 48-hour period. The median values for the healthy subjects at 2, 4, 8, and 24, and 48 hours were 1.44{+-}0.2 (midway through ascending), 1.71{+-}0.45 (midway through transverse), 2.64{+-}0.95 (midway through descending), 3.94{+-}0.89 (midway through rectosigmoid), and 4.52{+-}0.76 (midway through the stool compartment). On the contrary, the values of ten patients with colonic inertia were 1.0{+-}0.0 (midway through ascending), 1.0{+-}0.0 (midway through ascending). 1.02 {+-}0.06 (midway through ascending), 1.70{+-}0.36 (midway through transverse), and 2.33{+-}0.31(midway through descending) at the same time (p<0.001). In patients with idiopathic constipation is characterized by exaggerated reservoir factions of the ascending and transverse colons. Scintigraphy using 67 Gallium-labelled pellets seems to be a useful tool to demonstrate the delayed colonic transit in patients with colonic inertia.

  1. Diagnostic accuracy of the Barr and Blethyn radiological scoring systems for childhood constipation assessed using colonic transit time as the gold standard

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    Jackson, Claire R.; Wylie, Anna B.Z.; Adams, Charlotte [Royal Victoria Infirmary, Department of Paediatric Surgery, Newcastle upon Tyne (United Kingdom); Lee, Richard E. [Royal Victoria Infirmary, Department of Radiology, Newcastle upon Tyne (United Kingdom); Jaffray, Bruce [University of Newcastle upon Tyne, School of Clinical Medical Sciences (Child Health), Sir James Spence Institute, Newcastle upon Tyne (United Kingdom)

    2009-07-15

    Constipation is a common childhood symptom and abdominal radiography is advocated in diagnosis and management. To assess the reproducibility and diagnostic accuracy of the Barr and Blethyn systems for quantifying constipation on abdominal radiographs in children. Radiographs were scored by three observers of increasing radiological experience (student, junior doctor, consultant). Abdominal radiographs produced during measurement of colonic transit time (CTT) were classified as constipated or normal based on the value of the transit time, and were scored using both systems by observers blinded to the CTT. Abdominal radiographs obtained in children for reasons other than constipation were classed as normal and similarly scored. Reproducibility was measured using the kappa statistic. Diagnostic accuracy was measured using the area under the curve (AUC) for the receiver operator characteristic (ROC) curve. Using either system, scores were higher for constipated children (P<0.01). The consultant produced higher scores than the other observers (P<0.01). Interobserver reproducibility was moderate with the best kappa value only 0.48. The best correlation between score and CTT was 0.51 (junior doctor scores). Diagnostic accuracy of the scores was only moderate, with the largest AUC for a ROC curve of 0.84 for the consultant using the Barr score. Scoring of abdominal radiographs in the assessment of childhood constipation should be abandoned because it is dependent on the experience of the observer, is poorly reproducible, and does not accurately discriminate between constipated children and children without constipation. (orig.)

  2. Ingestão de fibra alimentar e tempo de trânsito colônico em pacientes com constipação funcional Fiber intake and colonic transit time in functional constipated patients

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    Adriana Cruz Lopes

    2008-03-01

    Full Text Available RACIONAL: Pacientes com constipação funcional que não melhoram com suplementação de fibras dietéticas, representam importante problema clínico. OBJETIVOS: Avaliar as relações entre as quantidades de fibras ingeridas, intensidade da constipação e o tempo de trânsito colônico em pacientes com constipação funcional. MÉTODOS: Foram avaliados 30 pacientes constipados funcionais, sem melhoras após suplementação dietética com fibras e 18 pessoas controle, sadias, sem queixas digestivas, utilizando inquéritos individuais quanto à ingestão de fibras e a intensidade da constipação e, por meio da técnica dos marcadores radiopaco, o tempo de trânsito colônico, total e segmentar. RESULTADOS: Apesar da maior ingestão diária de fibras (26,3 ± 12,9 g, constipados x 9,3 ± 5,2 g, controles, os sintomas da constipação mostraram-se intensos nos constipados (escore médio = 21,3 ± 4,07. O tempo normal para o trânsito colônico foi de 58,8h. O trânsito colônico total, em média, foi mais lento nos constipados (41,0 ± 22,8h, constipados x 21,8 ± 18,5h, controles. Constipados com trânsito lento (>58,8h apresentaram inércia colônica (oito, obstrução de saída (um e lentificação no cólon esquerdo (um. Constipados com trânsito normal (BACKGROUND: Patients with functional constipation presenting no response to treatment using fibers supplement represents important clinical issue. AIMS: To evaluate the relations among the amount of ingested fiber, the constipation intensity and the colonic transit time in patients with functional constipation. METHODS: We evaluated 30 patients, presenting no response to treatment using fibers supplement, and 18 healthy volunteers conducting individual inquiry into fibers intake, constipation intensity and the total and segmental colonic transit evaluation using radiopaque markers. RESULTS: In the constipated, despite the good level of fiber intake (26.3 ± 12.9 g, constipated x 9.3 ± 5,2 g

  3. Performance characteristics of scintigraphic colon transit measurement in health and irritable bowel syndrome and relationship to bowel functions.

    Science.gov (United States)

    Deiteren, A; Camilleri, M; Bharucha, A E; Burton, D; McKinzie, S; Rao, A S; Zinsmeister, A R

    2010-04-01

    The inter- and intra-subject variations of scintigraphy, which are used to identify colonic transit disturbances in irritable bowel syndrome (IBS), are unclear. The relationship between colonic transit and bowel functions is incompletely understood. To assess inter- and intra-subject variations of scintigraphic colonic transit measurements in 86 IBS patients and 17 healthy subjects and to quantify the relationship between colonic transit and bowel symptoms in 147 IBS patients and 46 healthy subjects. Data from participants with multiple colonic transit measurements were analysed. Primary end points were colonic filling at 6 h (CF6h) and geometric center (GC) at 24 and 48 h for colonic transit. Bowel functions were assessed by daily stool diaries. Inter- and intra-subject variations were greater for small intestinal than colonic transit. Overall, inter- and intra-subject variations were relatively narrow for colonic transit (both GC24h and GC48h, with lower COV at 48 h); there was little intra-subject variation in health and IBS-constipation over a period of Colonic transit was significantly associated with stool form (accounting for 19-27% of the variance), frequency (19%), and ease of stool passage (12%). Despite inter-subject variation in scintigraphic colonic transit results, the intra-subject measurements are reproducible over time in healthy volunteers and patients with IBS; significant changes in colonic transit at 24 h were observed only in IBS-D. Colonic transit is associated with stool form, frequency and ease of passage.

  4. Dispersal time for ancient human migrations: Americas and Europe colonization

    Science.gov (United States)

    Flores, J. C.

    2007-07-01

    I apply the recently proposed intermittence strategy to investigate the ancient human migrations in the world. That is, the Americas colonization (Bering-bridge and Pacific-coast theories) and Neanderthal replacement in Europe around 45000 years before the present. Using a mathematical equation related to diffusion and ballistic motion, I calculate the colonization time in all these cases in good agreement with archeological data (including Neolithic transition in Europe). Moreover, to support these calculations, I obtain analytically the effective speed of colonization in Europe veff=0.62 [km/yr] and related to the Aurignacian culture propagation.

  5. Simplified scintigraphic methods for measuring gastrointestinal transit times

    DEFF Research Database (Denmark)

    Graff, J; Brinch, K; Madsen, Jan Lysgård

    2000-01-01

    To investigate whether simple transit measurements based on scintigraphy performed only 0, 2, 4 and 24 h after intake of a radiolabelled meal can be used to predict the mean transit time values for the stomach, the small intestine, and the colon, a study was conducted in 16 healthy volunteers...... intestinal and colonic mean transit times were calculated for both markers and compared with fractional gastric emptying at 2 h, fractional colonic filling at 4 h, and geometric centre of colonic content at 24 h, respectively. Highly significant correlations were found between gastric mean transit time...... and fractional gastric emptying at 2 h (111In: r=0.95, Ptime and fractional colonic filling at 4 h (111In: r=-0.97, Ptime and geometric centre of colonic content...

  6. Functional fecal retention visualized by (111)In-DTPA colon transit scintigraphy.

    Science.gov (United States)

    Infante, Jose Rafael; Rayo, Juan I; Serrano, Justo; Dominguez, Maria L; Garcia, Lucia; Moreno, Manuel

    2015-06-01

    Constipation is an extremely common problem in children, varying from mild and short-lived to severe and chronic. Chronic constipation is a serious childhood condition and requires further investigation, including blood test, colonoscopy, radio-opaque marker study, and/or scintigraphy. We present small bowel and colon transit scintigraphy of a 14-year-old girl with history of chronic constipation, abdominal pain, weight loss, and poor response to medical treatment. After oral administration of In-DTPA in water, planar and SPECT/CT images showed normal small bowel transit time and functional fecal retention in colon transit study.

  7. Colonic transit in rats: effect of ovariectomy, sex steroid hormones, and pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, J.P.; Bhojwani, A.

    1986-07-01

    In vitro studies suggest that the female sex steroid hormones (estrogen (E) and progesterone (P)) can affect the myoelectric and mechanical activity of colonic smooth muscle. The present study was designed to examine the influence of the hormones on colonic transit in vivo. Transit was assessed by quantifying the distribution within the colon of a radiolabeled marker (0.5 Ci Na2V CrO4), using the geometric center method of analysis. Studies were performed with adult male rats and the following groups of female rats: nonpregnant, ovariectomized, ovariectomy plus hormone pretreatment, and pregnant (day 18). Hormone-pretreated animals were studied 24 h following the fourth injection. The data can be summarized as follows. 1) Colonic transit was affected by the timing of the estrus cycle. 2) Ovariectomy eliminated the biphasic transit pattern observed in estruscycling females and resulted in a geometric center value comparable with that of the metestrus-diestrus animals. 3) E + P pretreatment of ovariectomized rats resulted in a significant decrease in the geometric center compared with the untreated ovariectomized rats. 4) The geometric center value in pregnant anials and hormone-pretreated animals. 5) Adult male rats had a geometric center value of 4.12 +/- 0.29. The results suggest that a relation exists between colonic transit and the circulating levels of the steroid hormones.

  8. Gastrointestinal mean transit times in young and middle-aged healthy subjects

    DEFF Research Database (Denmark)

    Graff, J; Brinch, K; Madsen, Jan Lysgård

    2001-01-01

    To investigate the effects of age and gender on gastric, small intestinal and colonic mean transit times, a study was conducted in 32 healthy volunteers: eight young women (22-30 years), eight young men (20-28 years), eight middle-aged women (43-51 years) and eight middle-aged men (38-53 years......, small intestinal and colonic mean transit times were calculated. The gastric, small intestinal and colonic mean transit times were significantly longer in women. Ageing was shown to accelerate the gastric and small intestinal transit significantly. In the group of men the colonic mean transit time...... was unaffected by age, but middle-aged women had a significantly slower colonic transit than young women. We therefore conclude that both age and gender have to be considered when reference values for gastric, small intestinal and colonic mean transit times have to be established....

  9. Gallium-67 activated charcoal: a new method for preparation of radioactive capsules for colonic transit study

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Kai-Yuan [Department of Radiological Technology, ChungTai Institute of Health Sciences and Technology, Taichung (Taiwan); Tsai, Shih-Chuan [Department of Nuclear Medicine, Show Chwan Memorial Hospital, Changhua (Taiwan); Lin, Wan-Yu. [Department of Nuclear Medicine, Taichung Veterans General Hospital, 160 Taichung Harbor Road, Section 3, 40705, Taichung (Taiwan)

    2003-06-01

    Indium-111 is currently the radionuclide of choice for colonic transit study. However, it is expensive and not available in many hospitals. Technetium-99m has been proposed for colonic transit study but the short half-life has limited its use. Gallium-67 citrate is inexpensive and available in most countries. Most importantly, it has a suitable half-life for colonic transit study. Attempts have been made in some studies to use {sup 67}Ga citrate to label activated charcoal, but the results have not been good because of poor stability. In this study, we successfully labelled activated charcoal with {sup 67}Ga citrate by adding alcohol and 5% glucose solution. To evaluate the in vitro stability, the {sup 67}Ga-activated charcoal was incubated in a milieu mimicking the intestinal content, containing lipase, trypsin and glycochenodeoxycholate at different pH values (6.0, 7.0, 7.4 and 8.0) and for different durations (0 h, 24 h, 48 h, 72 h and 96 h). For the in vivo study, the {sup 67}Ga-activated charcoal was loaded into a commercial empty enteric capsule. Colonic transit scintigraphy was performed in five volunteers, including three healthy people and two constipated patients, after intake of the radioactive capsule. Images were obtained at 2 h, 4 h, 6 h, 8 h, 24h, 48 h, 72 h etc. until no radioactivity was detected in the bowel. Our data show that the in vitro stability of {sup 67}Ga-activated charcoal was good. The labelling efficiency still exceeded 91% at 96 h at pH values of 6.0, 7.0 and 7.4. In the group with a pH value of 8.0, the labelling efficiency gradually fell during the 4-day incubation but was still higher than 88% at the end of the fourth day. In the in vivo study, most capsules disintegrated in the caecum/colon region, and the {sup 67}Ga-activated charcoal mixed very well with bowel content. In addition, the radioactive charcoal could be detected clearly on the 72-h image, which is very important for the evaluation of colonic transit time in patients

  10. Microbial Mineral Colonization Across a Subsurface Redox Transition Zone

    Directory of Open Access Journals (Sweden)

    Brandon eConverse

    2015-08-01

    Full Text Available This study employed 16S rRNA gene amplicon pyrosequencing to examine the hypothesis that chemolithotrophic Fe(II-oxidizing bacteria (FeOB would preferentially colonize the Fe(II-bearing mineral biotite compared to quartz sand when the minerals were incubated in situ within a subsurface redox transition zone (RTZ at the Hanford 300 Area site in Richland, WA, USA. The work was motivated by the recently documented presence of neutral-pH chemolithotrophic FeOB capable of oxidizing structural Fe(II in primary silicate and secondary phyllosilicate minerals in 300 Area sediments and groundwater (Benzine et al., 2013. Sterilized portions of sand+biotite or sand alone were incubated in situ for five months within a multilevel sampling (MLS apparatus that spanned a ca. 2-m interval across the RTZ in two separate groundwater wells. Parallel MLS measurements of aqueous geochemical species were performed prior to deployment of the minerals. Contrary to expectations, the 16S rRNA gene libraries showed no significant difference in microbial communities that colonized the sand+biotite versus sand-only deployments. Both mineral-associated and groundwater communities were dominated by heterotrophic taxa, with organisms from the Pseudomonaceae accounting for up to 70% of all reads from the colonized minerals. These results are consistent with previous results indicating the capacity for heterotrophic metabolism (including anaerobic metabolism below the RTZ as well as the predominance of heterotrophic taxa within 300 Area sediments and groundwater. Although heterotrophic organisms clearly dominated the colonized minerals, several putative lithotrophic (NH4+, H2, Fe(II, and HS- oxidizing taxa were detected in significant abundance above and within the RTZ. Such organisms may play a role in the coupling of anaerobic microbial metabolism to oxidative pathways with attendant impacts on elemental cycling and redox-sensitive contaminant behavior in the vicinity of the

  11. Scintigraphic evaluation of colonic transit in two patients with idiopathic chronic constipation.

    Science.gov (United States)

    Ramachandran, A; Gupta, S M; Whelan, T; Johns, W

    2000-02-01

    Bowel transit in two women with protracted constipation was evaluated after oral administration of In-111 DTPA in water. Serial abdominal images were obtained for as long as 96 hours to assess transit through the stomach, small bowel, and colon. In both patients, large bowel transit was delayed. A pattern of colonic inertia was observed in one patient, whereas retention in the distal colon was seen in the other patient. Both patients underwent total colectomy with marked symptomatic relief. Colonic transit studies of these patients are presented, and the literature is reviewed.

  12. Clinical pharmacodynamics of SDZ HTF 919, a new 5-HT4 receptor agonist, in a model of slow colonic transit.

    Science.gov (United States)

    Appel, S; Kumle, A; Meier, R

    1997-11-01

    To explore the pharmacodynamic effects of the new promotile agent SDZ HTF 919, a selective partial 5-HT4 receptor agonist, in healthy subjects. A pharmacodynamic model was applied to prolong colonic transit by dietary means. Subsequently, the effects of twice-daily multiple doses of SDZ HTF 919 (1, 5, 25, and 100 mg) were investigated in a randomized, double-blind, placebo-controlled parallel-group study with 12 subjects per dose level. The sequential design with three study periods of 7 days each included intake of a self-selected diet, a liquid formula diet with soluble fiber supplementation, and a fiber-supplemented diet together with either SDZ HTF 919 or placebo administration. Stool characteristics (frequency and consistency) and total colonic transit times (with use of radiopaque markers) were recorded in each study period. SDZ HTF 919 was well tolerated at all dose levels. The frequency of loose stool and headache increased with higher doses. After a fiber-supplemented diet intake, the median stool frequency decreased from 8 1/2-9 to 5-7 defecations per study period. SDZ HTF 919 in doses of 25 and 100 mg twice a day increased the stool frequency (p HTF 919 dose. A fiber-supplemented diet prolonged total colonic transit time in all groups by 45 hours on average. Twice-a-day administration of SDZ HTF 919 for 6 days in addition to a fiber-supplemented diet significantly shortened the total colonic transit time only at the 5 mg dose. The lack of effect at lower and higher SDZ HTF 919 doses suggests a biphasic dose-response relationship for total colonic transit time. The suitability of total colonic transit time measurements in healthy subjects as a surrogate marker should be confirmed by patient studies.

  13. HDAC inhibitors induce epithelial-mesenchymal transition in colon carcinoma cells.

    Science.gov (United States)

    Ji, Meiying; Lee, Eun Jeoung; Kim, Ki Bae; Kim, Yangmi; Sung, Rohyun; Lee, Sang-Jeon; Kim, Don Soo; Park, Seon Mee

    2015-05-01

    The effects of histone deacetylase (HDAC) inhibitors on epithelial-mesenchymal transition (EMT) differ in various types of cancers. We investigated the EMT phenotype in four colon cancer cell lines when challenged with HDAC inhibitors trichostatin A (TSA) and valproic acid (VPA) with or without transforming growth factor-β1 (TGF-β1) treatment. Four colon cancer cell lines with different phenotypes in regards to tumorigenicity, microsatellite stability and DNA mutation were used. EMT phenotypes were assessed by the expression of E-cadherin and vimentin using western blot analysis, immunofluorescence, quantitative real-time RT-PCR following treatment with TSA (100 or 200 nM) or VPA (0.5 mM) with or without TGF-β1 (5 ng/ml) for 24 h. Biological EMT phenotypes were also evaluated by cell morphology, migration and invasion assays. TSA or VPA induced mesenchymal features in the colon carcinoma cells by a decrease in E-cadherin and an increase in vimentin expression at the mRNA and protein levels. Confocal microscopy revealed membranous attenuation or nuclear translocation of E-cadherin and enhanced expression of vimentin. These responses occurred after 6 h and increased until 24 h. Colon cancer cells changed from a round or rectangular shape to a spindle shape with increased migration and invasion ability following TSA or VPA treatment. The susceptibility to EMT changes induced by TSA or VPA was comparable in microsatellite stable (SW480 and HT29) and microsatellite unstable cells (DLD1 and HCT116). TSA or VPA induced a mesenchymal phenotype in the colon carcinoma cells and these effects were augmented in the presence of TGF-β1. HDAC inhibitors require careful caution before their application as new anticancer drugs for colon cancers.

  14. SDZ HTF 919 stimulates canine colonic motility and transit in vivo.

    Science.gov (United States)

    Nguyen, A; Camilleri, M; Kost, L J; Metzger, A; Sarr, M G; Hanson, R B; Fett, S L; Zinsmeister, A R

    1997-03-01

    Effects of the nonbenzamide 5-hydroxytryptamine4 agonist SDZ HTF 919 on gastrointestinal motility are unclear. Our aim was to assess the in vivo effects on gastrointestinal and colonic transit of radiolabeled residue and on colonic phasic contractility. In six female dogs, transit was measured over a period of 2 days by radioscintigraphy and colonic motility was measured by pneumohydraulic perfusion manometry of the proximal and distal colon. SDZ HTF 919 was administered initially by bolus i.v. infusion, followed by s.c. injection 8 and 16 hr later. Doses tested were 0.03, 0.1 and 0.3 mg/kg, and isotonic saline and vehicle served as controls in each dog. Stomach and small bowel transit was not significantly altered by SDZ HTF 919. Overall, i.v. SDZ HTF 919 accelerated colonic transit during the first 1 hr, compared with controls. These effects were significant even with the lowest dose of SDZ HTF 919. Responses to higher infusion doses were more variable. SDZ HTF 919 did not cause significant changes in quantitative pressure indices, such as amplitude or motor index, in the small bowel or colon. Prolonged postprandial colonic contractions, each lasting >30 sec, were noted after each i.v. agent and were significantly more frequent with the 0.03 mg/kg dose than with control (vehicle) treatment. Thus, SDZ HTF 919 accelerates canine colonic transit in vivo during the first 1 hr after i.v. administration. SDZ HTF 919 appears to be a promising agent for stimulation of mammalian colonic transit.

  15. Species Turnover through Time: Colonization and Extinction Dynamics across Metacommunities.

    Science.gov (United States)

    Nuvoloni, Felipe Micali; Feres, Reinaldo José Fazzio; Gilbert, Benjamin

    2016-06-01

    Island biogeography and metacommunity theory often use equilibrium assumptions to predict local diversity, yet nonequilibrium dynamics are common in nature. In nonequilibrium communities, local diversity fluctuates through time as the relative importance of colonization and extinction change. Here, we test the prevalence and causes of nonequilibrium dynamics in metacommunities of mites associated with rubber trees distributed over large spatial (>1,000 km) and temporal (>30-60 generations) scales in Brazil. We measured colonization and extinction rates to test species turnover and nonequilibrium dynamics over a growing season. Mite metacommunities exhibited nonequilibrium dynamics for most months of the year, and these dynamics tracked climatic conditions. Monthly shifts in temperature of more than 1°C resulted in nonequilibrium dynamics, as did mean temperatures outside of two critical ranges. Nonequilibrium dynamics were caused by a change in colonization with temperature change and changes in both colonization and extinction with absolute temperature. Species turnover showed different trends; high relative humidity increased both colonization and extinction rates, increasing turnover but not nonequilibrium dynamics. Our study illustrates that testing nonequilibrium dynamics can provide new insights into the drivers of colonization, extinction, and diversity fluctuations in metacommunities.

  16. Pharmacogenetics of the effects of colesevelam on colonic transit in irritable bowel syndrome with diarrhea.

    Science.gov (United States)

    Wong, Banny S; Camilleri, Michael; Carlson, Paula J; Odunsi-Shiyanbade, Suwebatu; McKinzie, Sanna; Busciglio, Irene; Burton, Duane; Zinsmeister, Alan R

    2012-05-01

    Protein products of klothoβ (KLB) and fibroblast growth factor receptor 4 (FGFR4) impact fibroblast growth factor 19-mediated feedback inhibition of hepatic bile acid (BA) synthesis. Variants of KLB and FGFR4 influence colonic transit (CT) in diarrhea-predominant irritable bowel syndrome (IBS-D). The purpose of this study was to test the hypothesis that colesevelam's slowing effects on CT in IBS-D patients is influenced by genetic variants in KLB and FGFR4. We examined pharmacogenetic effects of KLB and FGFR4 coding variants (SNPs) on scintigraphic CT response to the BA sequestrant, colesevelam 1.875 g b.i.d. versus placebo (PLA) for 14 days in 24 female IBS-D patients. FGFR4 rs351855 and KLB rs497501 were associated with differential colesevelam effects on ascending colon (AC) half-emptying time (t(1/2), P = 0.046 and P = 0.085 respectively) and on overall CT at 24 h (geometric center, GC24: P = 0.073 and P = 0.042, respectively), with slower transit for rs351855 GA/AA (but not for GG) and rs497501 CA/AA (but not CC) genotypes. FGFR4 rs351855 and KLB rs4975017 SNPs may identify a subset of IBS-D patients with beneficial response to colesevelam.

  17. Gastrointestinal transit times and motility in patients with cystic fibrosis

    DEFF Research Database (Denmark)

    Hedsund, Caroline; Gregersen, Tine; Jønsson, Iben;

    2012-01-01

    OBJECTIVE: Patients with cystic fibrosis (CF) often suffer from gastrointestinal (GI) dysfunction including obstructive symptoms, malabsorption and pain, but the underlying pathophysiology remains obscure. AIM: To compare GI motility and transit times in CF patients and healthy controls. MATERIAL...... AND METHODS: Ten CF patients (five women, median age 23) with pancreatic insufficiency were studied. Total gastrointestinal transit time (GITT) and segmental colonic transit times (SCTT) were assessed by radiopaque markers. Gastric emptying and small intestinal transit were evaluated using the magnet......-based motility tracking system (MTS-1). With each method patients were compared with 16 healthy controls. RESULTS: Basic contraction frequencies of the stomach and small intestine were normal, but the pill reached the cecum after 7 h in only 20% of CF patients while in 88% of controls (p = 0.001). Paradoxically...

  18. Efeito do tratamento convencional da constipação crônica funcional no tempo de trânsito orocecal e colônico total e segmentar Effects of conventional treatment of chronic functional constipation on total and segmental colonic and orocecal transit times

    Directory of Open Access Journals (Sweden)

    Ana Cristina Fontenele Soares

    2009-08-01

    Full Text Available OBJETIVO: Avaliar o efeito do tratamento convencional da constipação crônica funcional no tempo de trânsito colônico total e segmentar e no tempo de trânsito orocecal. MÉTODOS: Foram incluídos 34 pacientes com constipação funcional atendidos consecutivamente em ambulatório especializado. O tempo de trânsito colônico total e segmentar foi avaliado com marcadores radiopacos. O tempo de trânsito orocecal da lactulose e do feijão foi avaliado com teste do hidrogênio no ar expirado. O tratamento constou de desimpactação, orientações gerais e de consumo de dieta rica em fibra alimentar e administração de óleo mineral. RESULTADOS: Na admissão, dismotilidade colônica foi encontrada em 71,9% (23/32 dos pacientes. Todos os pacientes que realizaram corretamente o tratamento apresentaram melhora clínica na sexta semana do tratamento quando 82,6% (19/23 daqueles com dismotilidade na admissão apresentaram normalização ou diminuição da gravidade no padrão de trânsito colônico. Observou-se redução do tempo de trânsito (medianas entre a admissão e a oitava semana de tratamento: trânsito orocecal da lactulose (de 70 para 50 minutos, p = 0,002, orocecal do feijão (de 240 para 220 minutos, p = 0,002 e colônico total (de 69,5 para 37,0 horas, p = 0,001. A necessidade de uso de óleo mineral para controle da constipação aos 12 meses de tratamento associou-se com persistência de trânsito colônico total superior a 62 horas na oitava semana de tratamento (p = 0,014. CONCLUSÃO: O programa terapêutico convencional proporcionou bons resultados independentemente da presença ou não de dismotilidade colônica na admissão ao estudo. As anormalidades da motilidade digestiva na constipação funcional da criança podem apresentar reversibilidade e ser de natureza secundária.OBJECTIVE: To evaluate the effects of conventional treatment of chronic functional constipation on total and segmental colonic transit times and on orocecal

  19. Searching for transit timing variations in transiting exoplanet systems

    CERN Document Server

    Hrudková, Marie; Benn, Chris; Pollacco, Don; Gibson, Neale; Joshi, Yogesh; Harmanec, Petr; Tulloch, Simon

    2008-01-01

    Searching for transit timing variations in the known transiting exoplanet systems can reveal the presence of other bodies in the system. Here we report such searches for two transiting exoplanet systems, TrES-1 and WASP-2. Their new transits were observed with the 4.2m William Herschel Telescope located on La Palma, Spain. In a continuing programme, three consecutive transits were observed for TrES-1, and one for WASP-2 during September 2007. We used the Markov Chain Monte Carlo simulations to derive transit times and their uncertainties. The resulting transit times are consistent with the most recent ephemerides and no conclusive proof of additional bodies in either system was found.

  20. Cigarette smoke extracts induced the colon cancer migration via regulating epithelial mesenchymal transition and metastatic genes in human colon cancer cells.

    Science.gov (United States)

    Kim, Cho-Won; Go, Ryeo-Eun; Lee, Hae-Miru; Hwang, Kyung-A; Lee, Kyuhong; Kim, Bumseok; Lee, Moo-Yeol; Choi, Kyung-Chul

    2017-02-01

    There was considerable evidence that exposure to cigarette smoke is associated with an increased risk for colon cancer. Nevertheless, the mechanism underlying the relationship between cigarette smoking and colon cancer remains unclear. Moreover, there were only a few studies on effects of complexing substance contained in cigarette smoke on colon cancer. Thus, we further investigated whether cigarette smoke extract (CSE) affects the cell cycle, apoptosis and migration of human metastatic colon cancer cells, SW-620. MTT assay revealed that SW-620 cell proliferation was significantly inhibited following treatments with all CSEs, 3R4F, and two-domestic cigarettes, for 9 days in a concentration-dependent manner. Moreover, CSE treatments decreased cyclin D1 and E1, and increased p21 and p27 proteins by Western blot analysis in SW-620 cells. Additionally, the treatment of the cells with CSE contributed to these effects expressing by apoptosis-related proteins. An increased migration or invasion ability of SW-620 cells following CSE treatment was also confirmed by a scratch or fibronectin invasion assay in vitro. In addition, the protein levels of E-cadherin as an epithelial maker were down-regulated, while the mesenchymal markers, N-cadherin, snail, and slug, were up-regulated in a time-dependent manner. A metastatic marker, cathepsin D, was also down-regulated by CSE treatment. Taken together, these results indicate that CSE exposure in colon cancer cells may deregulate the cell growth by altering the expression of cell cycle-related proteins and pro-apoptotic protein, and stimulate cell metastatic ability by altering epithelial-mesenchymal transition (EMT) markers and cathepsin D expression. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 690-704, 2017.

  1. Time- and dose-dependent effects of curcumin on gene expression in human colon cancer cells

    Directory of Open Access Journals (Sweden)

    van Erk Marjan J

    2004-05-01

    Full Text Available Abstract Background Curcumin is a spice and a coloring food compound with a promising role in colon cancer prevention. Curcumin protects against development of colon tumors in rats treated with a colon carcinogen, in colon cancer cells curcumin can inhibit cell proliferation and induce apoptosis, it is an anti-oxidant and it can act as an anti-inflammatory agent. The aim of this study was to elucidate mechanisms and effect of curcumin in colon cancer cells using gene expression profiling. Methods Gene expression changes in response to curcumin exposure were studied in two human colon cancer cell lines, using cDNA microarrays with four thousand human genes. HT29 cells were exposed to two different concentrations of curcumin and gene expression changes were followed in time (3, 6, 12, 24 and 48 hours. Gene expression changes after short-term exposure (3 or 6 hours to curcumin were also studied in a second cell type, Caco-2 cells. Results Gene expression changes (>1.5-fold were found at all time points. HT29 cells were more sensitive to curcumin than Caco-2 cells. Early response genes were involved in cell cycle, signal transduction, DNA repair, gene transcription, cell adhesion and xenobiotic metabolism. In HT29 cells curcumin modulated a number of cell cycle genes of which several have a role in transition through the G2/M phase. This corresponded to a cell cycle arrest in the G2/M phase as was observed by flow cytometry. Functional groups with a similar expression profile included genes involved in phase-II metabolism that were induced by curcumin after 12 and 24 hours. Expression of some cytochrome P450 genes was downregulated by curcumin in HT29 and Caco-2 cells. In addition, curcumin affected expression of metallothionein genes, tubulin genes, p53 and other genes involved in colon carcinogenesis. Conclusions This study has extended knowledge on pathways or processes already reported to be affected by curcumin (cell cycle arrest, phase

  2. Critical desertification transition in semi-arid ecosystems: The role of local facilitation and colonization rate

    Science.gov (United States)

    Corrado, Raffaele; Cherubini, Anna Maria; Pennetta, Cecilia

    2015-05-01

    In this work we study the effect of two different ecological mechanisms on the desertification transition in arid or semi-arid ecosystems, modeled by a stochastic cellular automaton. Namely we consider the role of the facilitation mechanism, i.e. the local positive effects of plants on their neighborhood and of colonization factors, such as seed production, survival and germination probabilities. Within the model, the strength of these two mechanisms is determined by the parameters f and b, respectively controlling the rates of the recovery and colonization processes. In particular we focus on the full desertification transition occurring at increasing value of the mortality rate m and we discuss how the values of f and b affect the critical mortality mc , the critical exponents β and γσ‧, determining the power-law scaling of the average vegetation density and of the root-mean-square deviation of the density fluctuations, and the character of the transition: continuous or abrupt. We show that mc strongly depends on both f and b, a dependence which accounts for the higher resilience of the ecosystems to external stresses as a consequence of an increased effectiveness of positive feedback effects. On the other hand, concerning the value of the exponents and the character of the transition, our results point out that both these features are unaffected by changes in the strength of the local facilitation. Viceversa, we show that an increase of the colonization factor b significantly modifies the values of the exponents and the order of the transition, changing a continuous transition into an abrupt one. We explain these results in terms of the different range of the interactions characterizing facilitation and colonization mechanisms.

  3. NO TRANSIT TIMING VARIATIONS IN WASP-4

    Energy Technology Data Exchange (ETDEWEB)

    Petrucci, R.; Schwartz, M.; Buccino, A. P.; Mauas, P. J. D. [Instituto de Astronomía y Física del Espacio (IAFE), Buenos Aires (Argentina); Jofré, E.; Cúneo, V.; Gómez, M. [CONICET, Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina); Martínez, C. [Observatorio Astronómico de Córdoba, Córdoba (Argentina)

    2013-12-20

    We present six new transits of the system WASP-4. Together with 28 light curves published in the literature, we perform a homogeneous study of its parameters and search for variations in the transits' central times. The final values agree with those previously reported, except for a slightly lower inclination. We find no significant long-term variations in i or R{sub P} /R {sub *}. The O-C mid-transit times do not show signs of transit timing variations greater than 54 s.

  4. A suppository-base-matrix tablet for time-dependent colon-specific delivery system

    Directory of Open Access Journals (Sweden)

    Meijuan Zou

    2014-09-01

    Full Text Available Our research has focused on the main design features and release performances of time-dependent colon-specific (TDCS delivery tablets, which relies on the relative constancy that is observed in the small intestinal transit time of dosage forms. But inflammatory bowel disease(IBD)can affect the transit time, and usually results in watery stool. Compared to the TDCS and wax-matrix TDCS tablet, a promising time-dependent colon-specific delivery system was investigated. In our study, a suppository-base-matrix coated tablet was evaluated. Water soluble suppository-base helps the expansion of tablet, facilitates uniform film dissolution and achives high osmotic pressure. Combining the expansion of carboxymethyl starch sodium (CMS-Na and the moisture absorption of NaCl, the coated TDCS tablet obtained a burst and targeted drug delivery system. A very good correlation between in vitro drug release and in vivo outcome was observed. This TDCS coated tablet provides a promising strategy to control drug release to the desired lower gastrointestinal region.

  5. Regional Gastrointestinal Transit Times in Patients With Carcinoid Diarrhea: Assessment With the Novel 3D-Transit System

    DEFF Research Database (Denmark)

    Gregersen, Tine; Haase, Anne-Mette; Schlageter, Vincent;

    2015-01-01

    BACKGROUND/AIMS: The paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea re-stricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has...... not yet been evaluated in any group of patients. We aimed to test the performance of 3D-Transit in patients with carcinoid diarrhea and to compare the patients' regional gastrointestinal transit times (GITT) and colonic motility patterns with those of healthy subjects. METHODS: Fifteen healthy volunteers...... = 0.045). CONCLUSIONS: Three-dimensional Transit allows assessment of regional GITT in patients with diarrhea. Patients with carcinoid diarrhea have faster than normal gastrointestinal transit due to faster small intestinal and colorectal transit times. The latter is caused by an increased frequency...

  6. Epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions in the colon

    Institute of Scientific and Technical Information of China (English)

    Ferenc Sipos; Orsolya Galamb

    2012-01-01

    Epithelial-to-mesenchymal and mesenchymal-to-epithelial transitions are well established biological events which have an important role in not just normal tissue and organ development,but in the pathogenesis of diseases.Increasing evidence has established their presence in the human colon during colorectal carcinogenesis and cancer invasion,chronic inflammation-related fibrosis and in the course of mucosal healing.A large body of evidence supports the role for transforming growth factor-β and its downstream Smad signaling,the phosphatidylinositol 3'-kinase/Akt/mTOR axis,the Ras-mitogen-activated protein kinase/Snail/Slug and FOXC2 pathway,and Hedgehog signaling and microRNAs in the development of colorectal cancers via epithelial-to-mesenchymal transition.C-met and Frizzled-7,among others,seem to be the principle effectors of mesenchymal-to-epithelial transition,hence have a role not just in mucosal regeneration but in the progression of colonic wall fibrosis.Here we discuss a role for these pathways in the initiation and development of the transition events.A better understanding of their induction and regulation may lead to the identification of pathways and factors that could be potent therapeutic targets.The inhibition of epithelial-to-mesenchymal transition using mTOR kinase inhibitors targeting the ATP binding pocket and which inhibit both mTORC1 and mTORC2,RNA aptamers or peptide mimetics,such as a Wnt5A-mimetic,may all be useful in both cancer treatment and delaying fibrosis,while the induction of mesenchymal-to-epithelial transition in induced pluripotent stem cells may enhance epithelial healing in the case of severe mucosal damage.The preliminary results of the current studies are promising,but more clinical investigations are needed to develop new and safe therapeutic strategies for diseases of the colon.

  7. Timing of Colonization of Caries-Producing Bacteria: An Approach Based on Studying Monozygotic Twin Pairs

    OpenAIRE

    Bockmann, Michelle R.; Harris, Abbe V.; Bennett, Corinna N.; Ruba Odeh; Hughes, Toby E.; Townsend, Grant C

    2011-01-01

    Findings are presented from a prospective cohort study of timing of primary tooth emergence and timing of oral colonization of Streptococcus mutans (S. mutans) in Australian twins. The paper focuses on differences in colonization timing in genetically identical monozygotic (MZ) twins. Timing of tooth emergence was based on parental report. Colonization timing of S. mutans were established by plating samples of plaque and saliva on selective media at 3 monthly intervals and assessing colony mo...

  8. Duration Properties of Timed Transition Systems

    DEFF Research Database (Denmark)

    Liu, Zhiming; Ravn, Anders P.; Li, Xiaoshan

    1997-01-01

    This paper proposes a method for formal real-time systems development.The system requirements and high level design decisions are time interval properties, and are therefore specified in the Duration Calculus (DC), while the implementation and refinement are described in termsof timed transition ...

  9. Techniques for measuring renal transit time

    Energy Technology Data Exchange (ETDEWEB)

    Russell, C.D. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Japanwalla, M. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Khan, S. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Scott, J.W. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States); Dubovsky, E.V. [Div. of Nuclear Medicine, Univ. of Alabama at Birmingham Medical Center, AL (United States)]|[Nuclear Medicine Service, V.A. Medical Center, Birmingham, AL (United States)

    1995-12-01

    A variety of techniques have been used for quantitative estimation of renal transit time. We compared different indices of transit time in a group of 30 patients having baseline and ACE inhibitor technetium-99m mercaptoacetyltriglycine (MAG{sub 3}) renography prior to arteriography: Peak time, mean transit time, and the ratio of background-subtracted counts at 20 min to those at 3 min. Each index was calculated from whole-kidney ROI, cortical ROI, and cortical factor (by factor analysis). The strongest correlations between angiographic percent of stenosis and transit time index were observed for the peak time (Spearman {rho}=0.469, n=53) and for the R20/3 (again {rho}=0.469, n=53) using the whole-kidney ROI and using only the baseline data without captopril. (Spearman`s {rho} is simply the correlation coefficient calculated from rank in list, which allows for nonlinear correlation.) Thus simple indices of transit time (whole-kidney peak time and R20/3) correlated as well with the observed pathology as did more complicated methods that required deconvolution, factor analysis, or selection of a cortical ROI. (orig./MG)

  10. A search for transit timing variation

    Directory of Open Access Journals (Sweden)

    Kramm U.

    2011-02-01

    Full Text Available Photometric follow-ups of transiting exoplanets (TEPs may lead to discoveries of additional, less massive bodies in extrasolar systems. This is possible by detecting and then analysing variations in transit timing of transiting exoplanets. In 2009 we launched an international observing campaign, the aim of which is to detect and characterise signals of transit timing variation (TTV in selected TEPs. The programme is realised by collecting data from 0.6-2.2-m telescopes spread worldwide at different longitudes. We present our observing strategy and summarise first results for WASP-3b with evidence for a 15 Earth-mass perturber in an outer 2:1 orbital resonance.

  11. Late-time cosmological phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (USA) Fermi National Accelerator Lab., Batavia, IL (USA))

    1990-11-01

    It is shown that the potential galaxy formation and large-scale structure problems of objects existing at high redshifts (Z {approx gt} 5), structures existing on scales of 100M pc as well as velocity flows on such scales, and minimal microwave anisotropies ({Delta}T/T) {approx lt} 10{sup {minus}5} can be solved if the seeds needed to generate structure form in a vacuum phase transition after decoupling. It is argued that the basic physics of such a phase transition is no more exotic than that utilized in the more traditional GUT scale phase transitions, and that, just as in the GUT case, significant random gaussian fluctuations and/or topological defects can form. Scale lengths of {approximately}100M pc for large-scale structure as well as {approximately}1 M pc for galaxy formation occur naturally. Possible support for new physics that might be associated with such a late-time transition comes from the preliminary results of the SAGE solar neutrino experiment, implying neutrino flavor mixing with values similar to those required for a late-time transition. It is also noted that a see-saw model for the neutrino masses might also imply a tau neutrino mass that is an ideal hot dark matter candidate. However, in general either hot or cold dark matter can be consistent with a late-time transition. 47 refs., 2 figs.

  12. Slope Transit Time (STT): A Pulse Transit Time Proxy requiring Only a Single Signal Fiducial Point.

    Science.gov (United States)

    Addison, Paul S

    2016-11-01

    A novel pulse transit time proxy measurement, slope transit time (STT), is proposed in this letter. STT is based on geometrical considerations of the arriving photoplethysmographic cardiac waveform and its computation requires only the measurement of a single point on each cardiac beat arriving at the peripheral site. This novel transit time is explained conceptually and its implementation illustrated through its application to signals from respiratory effort, Müller maneuver, and obstructive sleep apnea trials.

  13. Verifying duration properties of timed transition systems

    DEFF Research Database (Denmark)

    Liu, Zhiming; Ravn, Anders P.; Li, Xiaoshan

    1998-01-01

    This paper proposes a method for formal real-time systems development:Requirements and high level design decisions are time interval properties and are therefore specified in the Duration Calculus (DC), while implementations are described bytimed transition systems (TTS). A link from implementati...

  14. Salvinorin A inhibits colonic transit and neurogenic ion transport in mice by activating kappa-opioid and cannabinoid receptors.

    Science.gov (United States)

    Fichna, J; Schicho, R; Andrews, C N; Bashashati, M; Klompus, M; McKay, D M; Sharkey, K A; Zjawiony, J K; Janecka, A; Storr, M A

    2009-12-01

    The major active ingredient of the plant Salvia divinorum, salvinorin A (SA) has been used to treat gastrointestinal (GI) symptoms. As the action of SA on the regulation of colonic function is unknown, our aim was to examine the effects of SA on mouse colonic motility and secretion in vitro and in vivo. The effects of SA on GI motility were studied using isolated preparations of colon, which were compared with preparations from stomach and ileum. Colonic epithelial ion transport was evaluated using Ussing chambers. Additionally, we studied GI motility in vivo by measuring colonic propulsion, gastric emptying, and upper GI transit. Salvinorin A inhibited contractions of the mouse colon, stomach, and ileum in vitro, prolonged colonic propulsion and slowed upper GI transit in vivo. Salvinorin A had no effect on gastric emptying in vivo. Salvinorin A reduced veratridine-, but not forskolin-induced epithelial ion transport. The effects of SA on colonic motility in vitro were mediated by kappa-opioid receptors (KORs) and cannabinoid (CB) receptors, as they were inhibited by the antagonists nor-binaltorphimine (KOR), AM 251 (CB(1) receptor) and AM 630 (CB(2) receptor). However, in the colon in vivo, the effects were largely mediated by KORs. The effects of SA on veratridine-mediated epithelial ion transport were inhibited by nor-binaltorphimine and AM 630. Salvinorin A slows colonic motility in vitro and in vivo and influences neurogenic ion transport. Due to its specific regional action, SA or its derivatives may be useful drugs in the treatment of lower GI disorders associated with increased GI transit and diarrhoea.

  15. Reference values for the geometric centre analysis of colonic transit measurements with 111indium-labelled diethylenetriamine penta-acetic acid

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Fuglsang, Stefan; Graff, Jesper

    2003-01-01

    The geometric centre analysis is often used for evaluating colonic transit data obtained by scintigraphy after oral intake of 111indium-labelled diethylenetriamine penta-acetic acid (111In-DTPA). The purpose of this study was to establish reference values for the geometric centre analysis in adult...... humans. Forty-eight healthy volunteers (24 women, 24 men) who were equally distributed among three age groups (young, middle-aged, elderly) were studied. In all subjects the geometric centre of radioactivity in the colon was calculated from abdominal gamma camera images acquired 24, 48, 72, and 96 h...... after oral administration of 111In-DTPA. Overall, the men had a higher geometric centre value than women after both 24 and 48 h indicating a faster progress of colonic contents in men at these time points. At each time point the geometric centre value was higher in both the young and middle...

  16. Transition Path Time Distribution, Tunneling Times, Friction, and Uncertainty

    Science.gov (United States)

    Pollak, Eli

    2017-02-01

    A quantum mechanical transition path time probability distribution is formulated and its properties are studied using a parabolic barrier potential model. The average transit time is well defined and readily calculated. It is smaller than the analogous classical mechanical average transit time, vanishing at the crossover temperature. It provides a direct route for determining tunneling times. The average time may be also used to define a coarse grained momentum of the system for the passage from one side of the barrier to the other. The product of the uncertainty in this coarse grained momentum with the uncertainty in the location of the particle is shown under certain conditions to be smaller than the ℏ/2 formal uncertainty limit. The model is generalized to include friction in the form of a bilinear interaction with a harmonic bath. Using an Ohmic friction model one finds that increasing the friction, increases the transition time. Only moderate values of the reduced friction coefficient are needed for the quantum transition time and coarse grained uncertainty to approach the classical limit which is smaller than ℏ/2 when the friction is not too small. These results show how one obtains classical dynamics from a pure quantum system without invoking any further assumptions, approximations, or postulates.

  17. Transit time for third order resonance extraction

    CERN Document Server

    Pullia, M

    1996-01-01

    An important spin-off from accelerators is the use of synchrotrons for cancer therapy. A precise control of the extraction from the synchrotron is needed to satisfy the medical specifications and this has led to a renewed interest in the basic theory of third-order resonance extraction. In the present paper, a complete description of the transit time in the resonance (the time between a particle becoming unstable and reaching the electrostatic septum) is developed as a basis for future work predicting spill shapes and the influence of power supply ripple. The transit time is evaluated for constant tune and for a slowly varying tune. Both cases are subdivided into particles that start close simulation and are shown to be correct to within a few percent.

  18. Regional Gastrointestinal Transit Times in Patients With Carcinoid Diarrhea: Assessment With the Novel 3D-Transit System

    Science.gov (United States)

    Gregersen, Tine; Haase, Anne-Mette; Schlageter, Vincent; Gronbaek, Henning; Krogh, Klaus

    2015-01-01

    Background/Aims The paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea restricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has not yet been evaluated in any group of patients. We aimed to test the performance of 3D-Transit in patients with carcinoid diarrhea and to compare the patients’ regional gastrointestinal transit times (GITT) and colonic motility patterns with those of healthy subjects. Methods Fifteen healthy volunteers and seven patients with neuroendocrine tumor and at least 3 bowel movements per day were investigated with 3D-Transit and standard radiopaque markers. Results Total GITT assessed with 3D-Transit and radiopaque markers were well correlated (Spearman’s rho = 0.64, P = 0.002). Median total GITT was 12.5 (range: 8.5–47.2) hours in patients versus 25.1 (range: 13.1–142.3) hours in healthy (P = 0.007). There was no difference in gastric emptying (P = 0.778). Median small intestinal transit time was 3.8 (range: 1.4–5.5) hours in patients versus 4.4 (range: 1.8–7.2) hours in healthy subjects (P = 0.044). Median colorectal transit time was 5.2 (range: 2.9–40.1) hours in patients versus 18.1 (range: 5.0–134.0) hours in healthy subjects (P = 0.012). Median frequency of pansegmental colonic movements was 0.45 (range: 0.03–1.02) per hour in patients and 0.07 (range: 0–0.61) per hour in healthy subjects (P = 0.045). Conclusions Three-dimensional Transit allows assessment of regional GITT in patients with diarrhea. Patients with carcinoid diarrhea have faster than normal gastrointestinal transit due to faster small intestinal and colorectal transit times. The latter is caused by an increased frequency of pansegmental colonic movements. PMID:26130638

  19. Transit timing observations from Kepler. V. Transit timing variation candidates in the first sixteen months from polynomial models

    DEFF Research Database (Denmark)

    Ford, E.B.; Ragozzine, D.; Holman, M.J.;

    2012-01-01

    Transit timing variations provide a powerful tool for confirming and characterizing transiting planets, as well as detecting non-transiting planets. We report the results of an updated transit timing variation (TTV) analysis for 1481 planet candidates based on transit times measured during...

  20. A Klothoβ variant mediates protein stability and associates with colon transit in irritable bowel syndrome with diarrhea.

    Science.gov (United States)

    Wong, Banny S; Camilleri, Michael; Carlson, Paula J; Guicciardi, Maria E; Burton, Duane; McKinzie, Sanna; Rao, Archana S; Zinsmeister, Alan R; Gores, Gregory J

    2011-06-01

    Bile acid (BA) malabsorption of moderate severity is reported in 32% of patients with chronic unexplained diarrhea, including diarrhea-predominant irritable bowel syndrome (IBS-D). We hypothesized that variants of genes regulating hepatic BA synthesis play a role in IBS-D. In 435 IBS and 279 healthy subjects, we tested individual associations of 15 common single nucleotide polymorphisms (SNPs) from 7 genes critical to BA homeostasis with symptom-based subgroups using dominant genetic models. In a subset of 238 participants, we tested association with colonic transit. SNP-SNP interactions were investigated based on known protein interactions in BA homeostasis. The function of SNP rs17618244 in Klothoβ (KLB) was evaluated using a protein stability assay in HEK293 cells. SNP rs17618244 (Arg728Gln in KLB) is associated with colonic transit at 24 hours. G allele (Arg728) compared with A allele (Gln728) is associated with accelerated colonic transit (P=.0007) in the overall cohort; this association was restricted to IBS-D (P=.0018). Interaction tests of KLB rs17618244 with 3 nonsynonymous SNPs of fibroblast growth factor receptor 4 (FGFR4) revealed that rs1966265 (Val10Ile) and rs351855 (Gly388Arg) modulate rs1768244's association with colonic transit in IBS-D (P=.0025 and P=.0023, respectively). KLB Arg728 significantly reduced protein stability compared with KLB Gln728, demonstrating KLB rs17618244's functional significance. No significant associations with symptom-based subgroups of IBS were detected. A functional KLB gene variant mediating protein stability associates with colonic transit in IBS-D. This association is modulated by 2 genetic variants in FGFR4. The FGF19-FGFR4-KLB pathway links regulation of BA synthesis to colonic transit in IBS-D. Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.

  1. Neutrino Oscillations and Short Transit Times

    CERN Document Server

    Horwitz, L P

    2012-01-01

    The Stueckelberg formulation of a manifestly covariant relativistic classical and quantum mechanics is briefly reviewed and it is shown that in this framework a simple model exists for which, for systems with flavor oscillations, beam transit times can be shortened. This phenomenon could account for the OPERA result, providing a mechanism for a "pull back" in measured time during the transit of a beam of neutrinos for which the speed is almost everywhere less than light speed. We show consistency of the model with the Lorentz force obtained from the Heisenberg equations associated with the Stueckelberg Hamiltonians generating the dynamics of a quantum particle, both without and with spin, in interaction with non-Abelian (Glashow-Salam-Weinberg type) gauge fields.

  2. Linking age, survival, and transit time distributions

    Science.gov (United States)

    Calabrese, Salvatore; Porporato, Amilcare

    2015-10-01

    Although the concepts of age, survival, and transit time have been widely used in many fields, including population dynamics, chemical engineering, and hydrology, a comprehensive mathematical framework is still missing. Here we discuss several relationships among these quantities by starting from the evolution equation for the joint distribution of age and survival, from which the equations for age and survival time readily follow. It also becomes apparent how the statistical dependence between age and survival is directly related to either the age dependence of the loss function or the survival-time dependence of the input function. The solution of the joint distribution equation also allows us to obtain the relationships between the age at exit (or death) and the survival time at input (or birth), as well as to stress the symmetries of the various distributions under time reversal. The transit time is then obtained as a sum of the age and survival time, and its properties are discussed along with the general relationships between their mean values. The special case of steady state case is analyzed in detail. Some examples, inspired by hydrologic applications, are presented to illustrate the theory with the specific results. This article was corrected on 11 Nov 2015. See the end of the full text for details.

  3. Steady state and time-resolved autofluorescence studies of human colonic tissues

    Institute of Scientific and Technical Information of China (English)

    Buhong Li; Zhenxi Zhang; Shusen Xie

    2006-01-01

    Steady state and time-resolved autofluorescence spectroscopies are employed to study the autofluorescence characteristics of human colonic tissues in vitro. The excitation wavelength varies from 260 to 540 nm, and the corresponding fluorescence emission spectra are acquired from 280 to 800 nm. Significant difference in fluorescence intensity of excitation-emission matrices (EEMs) is observed between normal and tumor colonic tissues. Compared with normal colonic tissue, low nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) and flavin adenine dinucleotide (FAD), and high amino acids and protoporphyrin Ⅸ (PpⅨ) fluorescences characterize high-grade malignant tissue. Moreover, the autofluorescence lifetimes of normal and carcinomatous colonic tissues at 635 nm under 397-nm excitation are about 4.32±0.12 and 18.45±0.05 ns, respectively. The high accumulation of endogenous PpⅨ in colonic cancers is demonstrated in both steady state and time-resolved autofluorescence spectroscopies.

  4. Central CRF, urocortins and stress increase colonic transit via CRF1 receptors while activation of CRF2 receptors delays gastric transit in mice.

    Science.gov (United States)

    Martínez, Vicente; Wang, Lixin; Rivier, Jean; Grigoriadis, Dimitri; Taché, Yvette

    2004-04-01

    Recently characterized selective agonists and developed antagonists for the corticotropin releasing factor (CRF) receptors are new tools to investigate stress-related functional changes. The influence of mammalian CRF and related peptides injected intracerebroventricularly (i.c.v.) on gastric and colonic motility, and the CRF receptor subtypes involved and their role in colonic response to stress were studied in conscious mice. The CRF(1)/CRF(2) agonists rat urocortin 1 (rUcn 1) and rat/human CRF (r/h CRF), the preferential CRF(1) agonist ovine CRF (oCRF), and the CRF(2) agonist mouse (m) Ucn 2, injected i.c.v. inhibited gastric emptying and stimulated distal colonic motor function (bead transit and defecation) while oCRF(9-33)OH (devoid of CRF receptor affinity) showed neither effects. mUcn 2 injected peripherally had no colonic effect. The selective CRF(2) antagonist astressin(2)-B (i.c.v.), at a 20 : 1 antagonist: agonist ratio, blocked i.c.v. r/hCRF and rUcn 1 induced inhibition of gastric transit and reduced that of mUcn 2, while the CRF(1) antagonist NBI-35965 had no effect. By contrast, the colonic motor stimulation induced by i.c.v. r/hCRF and rUcn 1 and 1h restraint stress were antagonized only by NBI-35965 while stimulation induced by mUcn 2 was equally blocked by both antagonists. None of the CRF antagonists injected i.c.v. alone influenced gut transit. These data establish in mice that brain CRF(1) receptors mediate the stimulation of colonic transit induced by central CRF, urocortins (1 and 2) and restraint stress, while CRF(2) receptors mediate the inhibitory actions of these peptides on gastric transit.

  5. Differential actions of peripheral corticotropin-releasing factor (CRF), urocortin II, and urocortin III on gastric emptying and colonic transit in mice: role of CRF receptor subtypes 1 and 2.

    Science.gov (United States)

    Martínez, Vicente; Wang, Lixin; Rivier, Jean E; Vale, Wylie; Taché, Yvette

    2002-05-01

    Peripheral CRF inhibits gastric emptying and stimulates colonic motor function in rats. We investigated the role of CRF(1) and CRF(2) receptors in i.p. CRF-induced alterations of gut transit in conscious mice using selective CRF(1) and CRF(2) ligands injected i.p. Gastric emptying 2 h after ingestion of a solid chow meal and colonic transit (time to expel a bead inserted into the distal colon) were determined simultaneously. Rat/human (r/h)CRF, which has CRF(1) > CRF(2) binding affinity, decreased distal colonic transit time at lower doses (6-12 microg/kg) than those inhibiting gastric emptying (20-60 microg/kg). Ovine CRF, a preferential CRF(1) receptor agonist (6-60 microg/kg), reduced significantly the colonic transit time without altering gastric emptying, whereas the selective CRF(2) receptor agonists mouse urocortin II (20-60 microg/kg) and urocortin III (120 microg/kg) inhibited significantly gastric emptying without modifying colonic transit. The CRF(1)/CRF(2) receptor antagonist, astressin (30-120 microg/kg), dose dependently prevented r/hCRF (20 microg/kg)-induced inhibition of gastric emptying and reduction of colonic transit time. The selective CRF(1) receptor antagonists, NBI-27914 (C(18)H(20)Cl(4)N(4)C(7)H(8)O(3)S) and CP-154,526 (butyl-[2,5-dimethyl-7-(2,4,6-trimethylphenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-yl]ethylamine) (5-30 mg/kg), dose dependently blocked r/hCRF action on the colon without influencing the gastric response, whereas the CRF(2) receptor antagonist, antisauvagine-30 (30-100 microg/kg), dose dependently abolished r/hCRF-induced delayed gastric emptying and had no effect on colonic response. These data show that i.p. r/hCRF-induced opposite actions on upper and lower gut transit in conscious mice are mediated by different CRF receptor subtypes: the activation of CRF(1) receptors stimulates colonic propulsive activity, whereas activation of CRF(2) receptors inhibits gastric emptying.

  6. SEDIMENT TOXICITY AND COMMUNITY COMPOSITION OF BENTHOS AND COLONIZED PERIPHYTON IN THE EVERGLADES - FLORIDA BAY TRANSITIONAL ZONE.

    Science.gov (United States)

    Lewis, Michael A., Larry R. Goodman, John M. Macauley and James C. Moore. 2004. Sediment Toxicity and Community Composition of Benthos and Colonized Periphyton in the Everglades-Florida Bay Transitional Zone. Ecotoxicology. 13(3):231-244. (ERL,GB 1164). This survey provid...

  7. Data processing in pulse transit time measurement

    Institute of Scientific and Technical Information of China (English)

    Jingmeng Zhang; Ye Li

    2008-01-01

    Pulse transit time(PTT) is used as a noninvasive and cuff-hss parameter to estimate blood pressure.In this paper,we develop an algorithm to obtain PTT rapidly,which is appropriate for micro-processor and could achieve good accuracy in PTT,even in noisy measurements.,The algorithm is based on finite impulse response(FIR) filter to reduce the noise and an adaptive threshold to detect the significant points of ECG and PPG.Evaluation of this method is based on the signals from our PTT-based blood pressure devices.It is shown that the method works well for PPT calculation.

  8. Emitter space charge layer transit time in bipolar junction transistors

    Science.gov (United States)

    Rustagi, S. C.; Chattopadhyaya, S. K.

    1981-04-01

    The charge defined emitter space charge layer transit times of double diffused transistors have been calculated using a regional approach, and compared with the corresponding base transit times. The results obtained for emitter space-charge layer transit times have been discussed with reference to the capacitance analysis of Morgan and Smit (1960) for graded p-n junctions.

  9. Effects of dietary fiber on gastrointestinal transit time, fecal properties and fat absorption in rats.

    Science.gov (United States)

    Munakata, A; Iwane, S; Todate, M; Nakaji, S; Sugawara, K

    1995-08-01

    The gastrointestinal transit time of food was determined by x-ray fluoroscopy using barium sulfate in rats fed with diets of various dietary fiber contents, and the effects of dietary fiber on the transit time, properties of feces, and fat absorption were examined. In 4- and 16-month-old rats fed with the diet for 3 and 15 month, respectively, the transit time of the cecum and colon in those receiving 20 and 40% wheat bran diets was shortened compared with that in the 0% group. The fecal pellet number and volume increased as the wheat bran content of the diet increased. In another experiments, the daily total fat excretion was found to be the greatest in rats receiving 15% pectin diet, followed by rats receiving 15% cellulose and non-fiber diets, respectively. These results suggest that shortening of the transit time through the cecum and colon with increase of fecal volume and suppression of fat absorption all participate in the mechanism of the inhibitory action of wheat bran on carcinogenesis and on the development of diverticulum of the large intestine.

  10. Aldehyde dehydrogenase-expressing colon stem cells contribute to tumorigenesis in the transition from colitis to cancer.

    Science.gov (United States)

    Carpentino, Joseph E; Hynes, Mark J; Appelman, Henry D; Zheng, Tong; Steindler, Dennis A; Scott, Edward W; Huang, Emina H

    2009-10-15

    Patients with chronic ulcerative colitis are at increased risk of developing colorectal cancer. Although current hypotheses suggest that sporadic colorectal cancer is due to inability to control cancer stem cells, the cancer stem cell hypothesis has not yet been validated in colitis-associated cancer. Furthermore, the identification of the colitis to cancer transition is challenging. We recently showed that epithelial cells with the increased expression of aldehyde dehydrogenase in sporadic colon cancer correlate closely with tumor-initiating ability. We sought to determine whether ALDH can be used as a marker to isolate tumor-initiating populations from patients with chronic ulcerative colitis. We used fluorescence-activated cell sorting to identify precursor colon cancer stem cells from colitis patients and report both their transition to cancerous stem cells in xenografting studies as well as their ability to generate spheres in vitro. Similar to sporadic colon cancer, these colitis-derived tumors were capable of propagation as sphere cultures. However, unlike the origins of sporadic colon cancer, the primary colitic tissues did not express any histologic evidence of dysplasia. To elucidate a potential mechanism for our findings, we compared the stroma of these different environments and determined that at least one paracrine factor is up-regulated in the inflammatory and malignant stroma compared with resting, normal stroma. These data link colitis and cancer identifying potential tumor-initiating cells from colitic patients, suggesting that sphere and/or xenograft formation will be useful to survey colitic patients at risk of developing cancer.

  11. Transition times in the Landau-Zener model

    CERN Document Server

    Vitanov, N V

    1999-01-01

    This paper presents analytic formulas for various transition times in the Landau-Zener model. Considerable differences are found between the transition times in the diabatic and adiabatic bases, and between the jump time (the time for which the transition probability rises to the region of its asymptotic value) and the relaxation time (the characteristic damping time of the oscillations which appear in the transition probability after the crossing). These transition times have been calculated by using the exact values of the transition probabilities and their derivatives at the crossing point and approximations to the time evolutions of the transition probabilities in the diabatic basis, derived earlier \\protect{[}N. V. Vitanov and B. M. Garraway, Phys. Rev. A {\\bf 53}, 4288 (1996)\\protect{]}, and similar results in the adiabatic basis, derived in the present paper.

  12. A link between lipid metabolism and epithelial-mesenchymal transition provides a target for colon cancer therapy

    OpenAIRE

    Sánchez-Martínez, Ruth; Cruz-Gil, Silvia; de Cedrón, Marta Gómez; Álvarez-Fernández, Mónica; Vargas, Teodoro; Molina, Susana; García, Belén; Herranz, Jesús; Moreno-Rubio, Juan; Reglero, Guillermo; Pérez-Moreno, Mirna; Feliu, Jaime; Malumbres, Marcos; de Molina, Ana Ramírez

    2015-01-01

    The alterations in carbohydrate metabolism that fuel tumor growth have been extensively studied. However, other metabolic pathways involved in malignant progression, demand further understanding. Here we describe a metabolic acyl-CoA synthetase/stearoyl-CoA desaturase ACSL/SCD network causing an epithelial-mesenchymal transition (EMT) program that promotes migration and invasion of colon cancer cells. The mesenchymal phenotype produced upon overexpression of these enzymes is reverted through ...

  13. Effects of alpha-glucosidase inhibitors on mouth to caecum transit time in humans.

    Science.gov (United States)

    Ladas, S D; Frydas, A; Papadopoulos, A; Raptis, S A

    1992-09-01

    The alpha-glucosidase inhibitors acarbose and miglitol have been successfully used to control postprandial hyperglycaemia in diabetics. They probably work by slowing carbohydrate digestion and absorption, but their effect on mouth to caecum transit time has not been studied. The effect acarbose (100 mg), miglitol (100 mg), and placebo on mouth to caecum transit time (380 kcal breakfast with 20 g of lactulose) was investigated in 18 normal volunteers using breath hydrogen analysis. Both miglitol and acarbose significantly increased breath hydrogen excretion (F2,34 = 6.31, p = 0.005) and shortened the mouth to caecum transit time (F2,34 = 3.49, p = 0.04) after breakfast compared with placebo. There was a significant negative correlation between breath hydrogen excretion and mouth to caecum transit time suggesting that with shorter transit times significantly more carbohydrates were spilled into the colon. These results indicate that alpha-glucosidase inhibitors accelerate mouth to caecum transit time by inducing carbohydrate malabsorption.

  14. [Effect of flooding time length on mycorrhizal colonization of three AM fungi in two wetland plants].

    Science.gov (United States)

    Ma, Lei-Meng; Wang, Peng-Teng; Wang, Shu-Guang

    2014-01-01

    In order to provide information for elucidating effect of flooding on the formation and function of AM in wetland plants, three AM fungi (Glomus intraradices, Glomus versiforme, Glomus etunicatum) were used to investigate the effects of flooding time length on their colonization in cattail (Typha orientalis) and rice (Oryza sativa L. ). The results showed that the mycorrhizal colonization rate (MCR) presented downtrend with increasing flooding time length. In cattail, MCR of the fungus F3 was higher than those of fungi F1 and F2, but no significant difference in MCR was found between fungi F1 and F2. In rice, the MCRs of fungi F2 and F3 were higher than that of E1. In both plants, the proportional frequency of hyphae was the highest while the proportional frequency of arbuscules and vesicles was very low in all treatments, indicating that hyphal colonization was the main route for AM formation. The proportional frequency of hyphae in cattail increased with the flooding time length, but no significant trend was observed in rice plant. The proportional frequency of arhuscules decreased with the increase of flooding time, and was the highest in the treatment without flooding (treatment IV). The number of spores produced by AM fungi increased with increasing flooding time, and reached the highest in the treatment of long time flooding (treatment I). In the same treatment, the fungus F3 produced more spores than fungi F1 and F2. Changes in wet weight of the two plants showed that AM could increase cattail growth under flooding, hut little effect on rice growth was found. It is concluded that flooding time length significantly affected the mycorrhizal colonization rate and the proportional frequency of colonization. AM could enhance the growth of wetland plant, but this depends on the mycorrhizal dependence of host plant on AM fungi. Therefore, flooding time length should be considered in the inoculation of wetland plants with AM fungi.

  15. TRANSIT TIMING OBSERVATIONS FROM KEPLER. VIII. CATALOG OF TRANSIT TIMING MEASUREMENTS OF THE FIRST TWELVE QUARTERS

    Energy Technology Data Exchange (ETDEWEB)

    Mazeh, Tsevi; Nachmani, Gil; Holczer, Tomer; Sokol, Gil [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of Chicago, 5640 Ellis Ave., Chicago, IL 60637 (United States); Ford, Eric B.; Ragozzine, Darin [Astronomy Department, University of Florida, Gainesville, FL 32111 (United States); Sanchis-Ojeda, Roberto [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Rowe, Jason F.; Lissauer, Jack J. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Zucker, Shay [Department of Geophysical, Atmospheric and Planetary Sciences, Raymond and Beverly Sackler Faculty of Exact Sciences Tel Aviv University, 69978 Tel Aviv (Israel); Agol, Eric [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Carter, Joshua A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Quintana, Elisa V. [SETI Institute, 189 Bernardo Ave, Suite 100, Mountain View, CA 94043 (United States); Steffen, Jason H. [Fermilab Center for Particle Astrophysics, P.O. Box 500, MS 127, Batavia, IL 60510 (United States); Welsh, William [Astronomy Department, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182 (United States)

    2013-10-01

    Following the works of Ford et al. and Steffen et al. we derived the transit timing of 1960 Kepler objects of interest (KOIs) using the pre-search data conditioning light curves of the first twelve quarters of the Kepler data. For 721 KOIs with large enough signal-to-noise ratios, we obtained also the duration and depth of each transit. The results are presented as a catalog for the community to use. We derived a few statistics of our results that could be used to indicate significant variations. Including systems found by previous works, we have found 130 KOIs that showed highly significant times of transit variations (TTVs) and 13 that had short-period TTV modulations with small amplitudes. We consider two effects that could cause apparent periodic TTV—the finite sampling of the observations and the interference with the stellar activity, stellar spots in particular. We briefly discuss some statistical aspects of our detected TTVs. We show that the TTV period is correlated with the orbital period of the planet and with the TTV amplitude.

  16. [Role of serotonin and histamine in the effects of degranulation of mast cells on the colonic motility and the transit. Experimental study in rats].

    Science.gov (United States)

    Castex, N; Fioramonti, J; Fargeas, M J; Bueno, L

    1993-01-01

    The aim of this work was to describe the alterations of colonic motility and transit induced by an experimental, histologically verified, degranulation of mast cells, provoked by the compound BrX-537A, and to determine the role of serotonin and histamine by specific antagonists, in the rat. Colonic myoelectrical activity was inhibited by BrX-537A (2 mg/kg IP) in a biphasic manner. The initial profound inhibition, lasting 30 min, during which the frequency of spike bursts decreased from 9.2 +/- 1.1 to 1.4 +/- 0.5/10 min, was followed by a sustained (5 h) period of moderate inhibition (5.2 +/- 0.5 spike bursts/10 min). In the same way, BrX-537A increased the mean retention time of a marker injected in the proximal colon (10.8 +/- 1.4 h vs 7.4 +/- 0.4 h). Neither serotoninergic nor histaminergic antagonists, at a dose of 1 mg/kg IP, modified the primary drastic inhibition of colonic motility during the first 20 minutes. After, a selective time-related blockade of this inhibition was observed. Granisetron blocked the inhibition from the 30th minute on, methysergide from the 120th minute on, and chlorpheniramine, between the 20th and 60th minutes. In conclusion, the inhibitory effect of mast cell degranulation depends on serotonin and histamine release, in a time-related manner, and implicates the H1, 5-HT3 and 5-HT1 or 2 receptors.

  17. Effects of a kefir supplement on symptoms, colonic transit, and bowel satisfaction score in patients with chronic constipation: a pilot study.

    Science.gov (United States)

    Turan, İlker; Dedeli, Özden; Bor, Serhat; İlter, Tankut

    2014-12-01

    Although probiotics have been extensively studied in irritable bowel syndrome, data on the impact of probiotics on chronic constipation are scarce. We aimed to evaluate the effects of kefir, which is a probiotic fermented milk product, on the symptoms, colonic transit, and bowel satisfaction scores of patients with chronic constipation. Twenty consecutive patients with functional constipation according to the Rome II criteria were divided into two groups based on their colon transit studies: 1. The normal transit (NT) group (n=10); and 2. The slow transit (ST) group (n=10). After a baseline period, 500 mL/day of a probiotic kefir beverage was administered to all patients for 4 weeks. Defecation parameters (stool frequency, stool consistency, degree of straining, laxative consumption) were recorded in diaries daily by the patients. Bowel satisfaction scores were assessed using a visual analog scale. The colon transit study was repeated in the ST group at the end of the study. At the end of the study, the patients showed an increased stool frequency (pkefir administration; however, this was not statistically significant (p=0.18). A repeat transit study showed an acceleration of colonic transit in the ST group (p=0.013). Bowel satisfaction scores also improved (pkefir has positive effects on the symptoms of constipation. Our results also suggest that kefir improves bowel satisfaction scores and accelerates colonic transit. Controlled trials are warranted to confirm these findings.

  18. Bigelow aerospace colonizing space one module at a time

    CERN Document Server

    Seedhouse, Erik

    2015-01-01

    Here for the first time you can read: how a space technology start-up is pioneering work on expandable space station modules how Robert Bigelow licensed the TransHab idea from NASA, and how his company developed the technology for more than a decade how, very soon, a Bigelow expandable module will be docked with the International Space Station. At the core of Bigelow's plan is the inflatable module technology. Tougher and more durable than their rigid counterparts, these inflatable modules are perfectly suited for use in the space, where Bigelow plans to link them together to form commercial space stations. This book describes how this new breed of space stations will be built and how the link between Bigelow Aerospace, NASA and private companies can lead to a new economy—a space economy. Finally, the book touches on Bigelow's aspirations beyond low Earth orbit, plans that include the landing of a base on the lunar surface and the prospect of missions to Mars.

  19. Transit light curves with finite integration time: Fisher information analysis

    Energy Technology Data Exchange (ETDEWEB)

    Price, Ellen M. [California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Rogers, Leslie A. [California Institute of Technology, MC249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

    2014-10-10

    Kepler has revolutionized the study of transiting planets with its unprecedented photometric precision on more than 150,000 target stars. Most of the transiting planet candidates detected by Kepler have been observed as long-cadence targets with 30 minute integration times, and the upcoming Transiting Exoplanet Survey Satellite will record full frame images with a similar integration time. Integrations of 30 minutes affect the transit shape, particularly for small planets and in cases of low signal to noise. Using the Fisher information matrix technique, we derive analytic approximations for the variances and covariances on the transit parameters obtained from fitting light curve photometry collected with a finite integration time. We find that binning the light curve can significantly increase the uncertainties and covariances on the inferred parameters when comparing scenarios with constant total signal to noise (constant total integration time in the absence of read noise). Uncertainties on the transit ingress/egress time increase by a factor of 34 for Earth-size planets and 3.4 for Jupiter-size planets around Sun-like stars for integration times of 30 minutes compared to instantaneously sampled light curves. Similarly, uncertainties on the mid-transit time for Earth and Jupiter-size planets increase by factors of 3.9 and 1.4. Uncertainties on the transit depth are largely unaffected by finite integration times. While correlations among the transit depth, ingress duration, and transit duration all increase in magnitude with longer integration times, the mid-transit time remains uncorrelated with the other parameters. We provide code in Python and Mathematica for predicting the variances and covariances at www.its.caltech.edu/∼eprice.

  20. Impact of in Vivo Ischemic Time on RNA Quality--Experiences from a Colon Cancer Biobank.

    Science.gov (United States)

    Olsen, Jesper; Kirkeby, Lene T; Eiholm, Susanne; Jess, Per; Troelsen, Jesper T; Gögenür, Ismail; Olsen, Jorgen

    2015-08-01

    Considerable effort has been made to improve differentiated diagnostics as well as personalized treatment for colorectal cancer patients. High-quality fresh frozen tissue is often required to investigate relevant molecular signatures in these patients. In RNA expression studies, the "RNA integrity number" is widely accepted as a reliable marker of RNA quality. Here, we investigate the feasibility of obtaining high-quality tissue from a colon cancer biobank and the impact of in vivo ischemic time and various technical and clinicopathological factors on RNA quality. Biopsies were obtained immediately following the tumor removal. The time from clamping the main arterial supply to resection and removal of the tumor was used to estimate the in vivo ischemic time. We did not observe a significant difference in RNA quality between normal tissue and tumor tissue. We observed a significant correlation between in vivo ischemic time and RNA quality in normal tissue (r = -0.24, ptime, surgical procedure, and gender have minor but significant effects on the quality of RNA from normal colon tissue but not tumor tissue. Poorly differentiated tumors are associated with lower RNA quality. Although its impact is low, it can still be considered to note in vivo ischemic time in colon cancer specimen procurement.

  1. Epithelial-mesenchymal transition associates with maintenance of stemness in spheroid-derived stem-like colon cancer cells.

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Han

    Full Text Available Despite earlier studies demonstrating characteristics of colon cancer stem cells (CCSCs and the role of epithelial-mesenchymal transition (EMT in tumor development, it remains controversial as to the relationship between CCSCs and EMT. In this study, in order to present an insight into this relationship in colon cancer, we developed HCT116 and HT29 sphere models, which are known to be the cells enriching cancer stem cells. Compared to their parental counterparts, spheroid cells displayed lower homotypic/heterotypic adhesion but higher in vitro migratory/invasive capacity, as well as higher tumorigenic and metastatic potential in vivo. The spheroid cells also demonstrated down-regulated E-cadherin and up-regulated α-SMA and Vimentin expression, which is the typical phenotype of EMT. In order to explore whether this phenomenon is associated to activation of Wnt/β-catenin pathway, we detected several key signaling molecules. Compared with their parental cells, HCT116 and HT29 spheroid cells demonstrated down-regulated expression of GSK3β, but up-regulated expression of Slug and Snail. And also, the up-regulation of nucleus β-catenin in spheroid cells indicated that the free β-catenin transferred from cytoplasm to cell nucleus. Our findings indicate that spheroid cells have the characteristics of colon cancer stem cells, and EMT may account for their stemness and malignancy. And persistent activation of Wnt/β-catenin pathway may play an important role in the EMT of CCSCs.

  2. Transit Light Curves with Finite Integration Time: Fisher Information Analysis

    CERN Document Server

    Price, Ellen M

    2014-01-01

    Kepler has revolutionized the study of transiting planets with its unprecedented photometric precision on more than 150,000 target stars. Most of the transiting planet candidates detected by Kepler have been observed as long-cadence targets with 30 minute integration times, and the upcoming Transiting Exoplanet Survey Satellite (TESS) will record full frame images with a similar integration time. Integrations of 30 minutes affect the transit shape, particularly for small planets and in cases of low signal-to-noise. Using the Fisher information matrix technique, we derive analytic approximations for the variances and covariances on the transit parameters obtained from fitting light curve photometry collected with a finite integration time. We find that binning the light curve can significantly increase the uncertainties and covariances on the inferred parameters when comparing scenarios with constant total signal-to-noise (constant total integration time in the absence of read noise). Uncertainties on the tran...

  3. The Transiting System GJ1214: High-Precision Defocused Transit Observations and a Search for Evidence of Transit Timing Variation

    DEFF Research Database (Denmark)

    Harpsøe, Kennet Bomann West; Hardis, S.; Hinse, T. C.;

    2012-01-01

    Aims: We present 11 high-precision photometric transit observations of the transiting super-Earth planet GJ1214b. Combining these data with observations from other authors, we investigate the ephemeris for possible signs of transit timing variations (TTVs) using a Bayesian approach. Methods......: The observations are used to determine the photometric parameters and the physical properties of the GJ1214 system. Our results are in good agreement with published values. Individual times of mid-transit are measured with uncertainties as low as 10s, allowing us to reduce the uncertainty in the orbital period...

  4. Transition Icons for Time Series Visualization and Exploratory Analysis.

    Science.gov (United States)

    Nickerson, Paul; Baharloo, Raheleh; Wanigatunga, Amal A; Manini, Todd D; Tighe, Patrick J; Rashidi, Parisa

    2017-05-16

    The modern healthcare landscape has seen the rapid emergence of techniques and devices which temporally monitor and record physiological signals. The prevalence of time series data within the healthcare field necessitates the development of methods which can analyze the data in order to draw meaningful conclusions. Time series behavior is notoriously difficult to intuitively understand due to its intrinsic high-dimensionality, which is compounded in the case of analyzing groups of time series collected from different patients. Our framework, which we call Transition Icons, renders common patterns in a visual format useful for understanding the shared behavior within groups of time series. Transition Icons are adept at detecting and displaying subtle differences and similarities e.g. between measurements taken from patients receiving different treatment strategies or stratified by demographics. We introduce various methods which collectively allow for exploratory analysis of groups of time series, while being free of distribution assumptions and including simple heuristics for parameter determination. Our technique extracts discrete transition patterns from Symbolic Aggregate approXimation (SAX) representations, and compiles transition frequencies into a Bag of Patterns (BoP) constructed for each group. These transition frequencies are normalized and aligned in icon form to intuitively display the underlying patterns. We demonstrate the Transition Icon technique for two time series data sets - postoperative pain scores, and hip-worn accelerometer activity counts. We believe Transition Icons can be an important tool for researchers approaching time series data, as they give rich and intuitive information about collective time series behaviors.

  5. Effect of Rapamycin on TGF-β1-induced epithelial-mesenchymal transition in LoVo colonic adenocarcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Renhu Sun; Jiang Li; Jing Cui; Qing Lv; Xinghua Liu; Guobin Wang

    2009-01-01

    Objective:To investigate the effect of Rapamycin on epithelial-mesenchyrnal transition(EMT) of LoVo colonic adenocarcinoma cells in vitro.Methods:Cultured LoVo colonic adenocarcinoma cells were divided into three groups: negative control group,EMT-inducing group(TGF-β1) and EMT-interfering group(TGF-β1 plus Rapamycin).E-cadherin expression in LoVo cells was detected by Western Blot,while the expression of vimentin was evaluated through immunocytochemistry.The Snail mRNA in LoVo cells was examined by RT-PCR.Results:TGF-β1 induced LoVo cell switching from polygonal to spindle-shaped.TGF-β1 enhanced the expression of vimentin,but lowered the level of E-cadherin.In contrast,Rapamycin impaired the transition induced by TGF-β1.Rapamycin dramatically abrogated TGF-β1-induced vimentin expression and restored E-cadherin expression in LoVo cells.Rapamycin significantly repressed the up-regulation of Snail mRNA expression induced by TGF-β1.Conclusion:Rapamycin dramatically abrogated TGF-β1 induced Snail mRNA expression in LoVo cells,hence inhibiting EMT of these cells in vitro.

  6. Transition path time distribution and the transition path free energy barrier.

    Science.gov (United States)

    Pollak, Eli

    2016-10-19

    The recent experimental measurement of the transition path time distributions of proteins presents several challenges to theory. Firstly, why do the fits of the experimental data to a theoretical expression lead to barrier heights which are much lower than the free energies of activation of the observed transitions? Secondly, there is the theoretical question of determining the transition path time distribution, without invoking the Smoluchowski limit. In this paper, we derive an exact expression for a transition path time distribution which is valid for arbitrary memory friction using the normal mode transformation which underlies Kramers' rate theory. We then recall that for low barriers, there is a noticeable difference between the transition path time distribution obtained with absorbing boundary conditions and free boundary conditions. For the former, the transition times are shorter, since recrossings of the boundaries are disallowed. As a result, if one uses the distribution based on absorbing boundary conditions to fit the experimental data, one will find that the transition path barrier will be larger than the values found based on a theory with free boundary conditions. We then introduce the paradigm of a transition path barrier height, and show that one should always expect it to be much smaller than the activation energy.

  7. Time- and dose-dependent effects of curcumin on gene expression in human colon cancer cells

    NARCIS (Netherlands)

    Erk, M.J. van; Teuling, E.; Staal, Y.C.M.; Huybers, S.; Bladeren, P.J. van; Aarts, J.M.M.J.G.; Ommen, B. van

    2004-01-01

    Background. Curcumin is a spice and a coloring food compound with a promising role in colon cancer prevention. Curcumin protects against development of colon tumors in rats treated with a colon carcinogen, in colon cancer cells curcumin can inhibit cell proliferation and induce apoptosis, it is an a

  8. Using long-term transit timing to detect terrestrial planets

    CERN Document Server

    Heyl, J S; Heyl, Jeremy S.; Gladman, Brett J.

    2006-01-01

    We propose that the presence of additional planets in extrasolar planetary systems can be detected by long-term transit timing studies. If a transiting planet is on an eccentric orbit then the presence of another planet causes a secular advance of the transiting planet's pericenter over and above the effect of general relativity. Although this secular effect is impractical to detect over a small number of orbits, it causes long-term differences in when future transits occur, much like the long-term decay observed in pulsars. Measuring this transit-timing delay would thus allow the detection of either one or more additional planets in the system or the first measurements of non-zero oblateness ($J_2$) of the central stars.

  9. AMON: Transition to real-time operations

    Science.gov (United States)

    Cowen, D. F.; Keivani, A.; Tešić, G.

    2016-04-01

    The Astrophysical Multimessenger Observatory Network (AMON) will link the world's leading high-energy neutrino, cosmic-ray, gamma-ray and gravitational wave observatories by performing real-time coincidence searches for multimessenger sources from observatories' subthreshold data streams. The resulting coincidences will be distributed to interested parties in the form of electronic alerts for real-time follow-up observation. We will present the science case, design elements, current and projected partner observatories, status of the AMON project, and an initial AMON-enabled analysis. The prototype of the AMON server has been online since August 2014 and processing archival data. Currently, we are deploying new high-uptime servers and will be ready to start issuing alerts as early as winter 2015/16.

  10. Pulse wave transit time for monitoring respiration rate.

    Science.gov (United States)

    Johansson, A; Ahlstrom, C; Lanne, T; Ask, P

    2006-06-01

    In this study, we investigate the beat-to-beat respiratory fluctuations in pulse wave transit time (PTT) and its subcomponents, the cardiac pre-ejection period (PEP) and the vessel transit time (VTT) in ten healthy subjects. The three transit times were found to fluctuate in pace with respiration. When applying a simple breath detecting algorithm, 88% of the breaths seen in a respiration air-flow reference could be detected correctly in PTT. Corresponding numbers for PEP and VTT were 76 and 81%, respectively. The performance during hypo- and hypertension was investigated by invoking blood pressure changes. In these situations, the error rates in breath detection were significantly higher. PTT can be derived from signals already present in most standard monitoring set-ups. The transit time technology thus has prospects to become an interesting alternative for respiration rate monitoring.

  11. A Quantitative Review and Meta-models of the Variability and Factors Affecting Oral Drug Absorption-Part II: Gastrointestinal Transit Time.

    Science.gov (United States)

    Abuhelwa, Ahmad Y; Foster, David J R; Upton, Richard N

    2016-09-01

    This study aimed to conduct a quantitative meta-analysis for the values of, and variability in, gastrointestinal (GI) transit times of non-disintegrating single-unit ("tablet") and multiple-unit ("pellets/multi-unit tablet") solid dosage forms, characterize the effect of food on the values and variability in these parameters and present quantitative meta-models of the distributions of GI transit times in the respective GI regions to help inform models of oral drug absorption. The literature was systemically reviewed for the values of, and the variability in, gastric, small intestinal and colonic transit times under fed and fasted conditions. Meta-analysis used the "metafor" package of the R language. Meta-models of GI transit were assumed to be log-normally distributed between the studied populations. Twenty-nine studies including 125 reported means and standard deviations were used in the meta-analysis. Caloric content of administered food increased variability and delayed the gastric transit of both pellets and tablets. Conversely, food caloric content reduced the variability but had no significant influence on the mean small intestinal transit time (SITT). Food had no significant effect on the transit time through the colon. The transit of pellets through the colon was significantly slower than that of single-unit tablets which is most likely related to their smaller size. GI transit times may influence the dissolution and absorption of oral drugs. The meta-models of GI transit times may be used as part of semi-physiological absorption models to characterize the influence of transit time on the dissolution, absorption and in vivo pharmacokinetic profiles of oral drugs.

  12. WASP-14 b: Transit Timing analysis of 19 light curves

    CERN Document Server

    Raetz, St; Seeliger, M; Marka, C; Fernandez, M; Güver, T; Gögüs, E; Nowak, G; Vanko, M; Berndt, A; Eisenbeiss, T; Mugrauer, M; Trepl, L; Gelszinnis, J

    2015-01-01

    Although WASP-14 b is one of the most massive and densest exoplanets on a tight and eccentric orbit, it has never been a target of photometric follow-up monitoring or dedicated observing campaigns. We report on new photometric transit observations of WASP-14 b obtained within the framework of "Transit Timing Variations @ Young Exoplanet Transit Initiative" (TTV@YETI). We collected 19 light-curves of 13 individual transit events using six telescopes located in five observatories distributed in Europe and Asia. From light curve modelling, we determined the planetary, stellar, and geometrical properties of the system and found them in agreement with the values from the discovery paper. A test of the robustness of the transit times revealed that in case of a non-reproducible transit shape the uncertainties may be underestimated even with a wavelet-based error estimation methods. For the timing analysis we included two publicly available transit times from 2007 and 2009. The long observation period of seven years ...

  13. Developments in Planet Detection using Transit Timing Variations

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab; Agol, Eric; /Washington U., Seattle, Astron. Dept.

    2006-12-01

    In a transiting planetary system, the presence of a second planet will cause the time interval between transits to vary. These transit timing variations (TTV) are particularly large near mean-motion resonances and can be used to infer the orbital elements of planets with masses that are too small to detect by any other means. The author presents the results of a study of simulated data where they show the potential that this planet detection technique has to detect and characterize secondary planets in transiting systems. These results have important ramifications for planetary transit searches since each transiting system presents an opportunity for additional discoveries through a TTV analysis. They present such an analysis for 13 transits of the HD 209458 system that were observed with the Hubble Space Telescope. This analysis indicates that a putative companion in a low-order, mean-motion resonance can be no larger than the mass of the Earth and constitutes, to date, the most sensitive probe for extrasolar planets that orbit main sequence stars. The presence or absence of small planets in low-order, mean-motion resonances has implications for theories of the formation and evolution of planetary systems. Since TTV is most sensitive in these regimes, it should prove a valuable tool not only for the detection of additional planets in transiting systems, but also as a way to determine the dominant mechanisms of planet formation and the evolution of planetary systems.

  14. Bisimulation and Open Maps for Timed Transition Systems

    DEFF Research Database (Denmark)

    Nielsen, Mogens

    1999-01-01

    Formal models for real-time systems have been studied intensively over the past decade. Much of the theory of untimed systems have been lifted to real-time settings. One example is the notion of bisimulation applied to timed transition systems, which is studied here within the general categorical...

  15. β-III tubulin modulates the behavior of Snail overexpressed during the epithelial-to-mesenchymal transition in colon cancer cells.

    Science.gov (United States)

    Sobierajska, Katarzyna; Wieczorek, Katarzyna; Ciszewski, Wojciech M; Sacewicz-Hofman, Izabela; Wawro, Marta E; Wiktorska, Magdalena; Boncela, Joanna; Papiewska-Pajak, Izabela; Kwasniak, Pawel; Wyroba, Elzbieta; Cierniewski, Czeslaw S; Niewiarowska, Jolanta

    2016-09-01

    Class III β-tubulin (TUBB3) is a marker of drug resistance expressed in a variety of solid tumors. Originally, it was described as an important element of chemoresistance to taxanes. Recent studies have revealed that TUBB3 is also involved in an adaptive response to a microenvironmental stressor, e.g. low oxygen levels and poor nutrient supply in some solid tumors, independently of the microtubule targeting agent. Furthermore, it has been demonstrated that TUBB3 is a marker of biological aggressiveness associated with modulation of metastatic abilities in colon cancer. The epithelial-to-mesenchymal transition (EMT) is a basic cellular process by which epithelial cells lose their epithelial behavior and become invasive cells involved in cancer metastasis. Snail is a zinc-finger transcription factor which is able to induce EMT through the repression of E-cadherin expression. In the presented studies we focused on the analysis of the TUBB3 role in EMT-induced colon adenocarcinoma cell lines HT-29 and LS180. We observed a positive correlation between Snail presence and TUBB3 upregulation in tested adenocarcinoma cell lines. The cellular and behavioral analysis revealed for the first time that elevated TUBB3 level is functionally linked to increased cell migration and invasive capability of EMT induced cells. Additionally, the post-transcriptional modifications (phosphorylation, glycosylation) appear to regulate the cellular localization of TUBB3 and its phosphorylation, observed in cytoskeleton, is probably involved in cell motility modulation.

  16. Transit timing analysis of CoRoT-1b

    CERN Document Server

    Csizmadia, Sz; Barge, P; Agol, E; Aigrain, S; Alonso, R; Almenara, J M; Bonomo, A S; Borde, P; Bouchy, F; Cabrera, J; Deeg, H J; De la Reza, R; Deleuil, M; Dvorak, R; Erikson, A; Guenther, E W; Fridlund, M; Gondoin, P; Guillot, T; Hatzes, A; Jorda, L; Lammer, H; Lázaro, C; Leger, A; Llebaria, A; Magain, P; Moutou, C; Ollivier, M; Paetzold, M; Queloz, D; Rauer, H; Rouan, D; Schneider, J; Wuchterl, G; Gandolfi, D

    2009-01-01

    CoRoT, the pioneer space-based transit search, steadily provides thousands of high-precision light curves with continuous time sampling over periods of up to 5 months. The transits of a planet perturbed by an additional object are not strictly periodic. By studying the transit timing variations (TTVs), additional objects can be detected in the system. A transit timing analysis of CoRoT-1b is carried out to constrain the existence of additional planets in the system. We used data obtained by an improved version of the CoRoT data pipeline (version 2.0). Individual transits were fitted to determine the mid-transit times, and we analyzed the derived $O-C$ diagram. N-body integrations were used to place limits on secondary planets. No periodic timing variations with a period shorter than the observational window (55 days) are found. The presence of an Earth-mass Trojan is not likely. A planet of mass greater than $\\sim 1$ Earth mass can be ruled out by the present data if the object is in a 2:1 (exterior) mean mot...

  17. Daylight Saving Time Transitions and Road Traffic Accidents

    Directory of Open Access Journals (Sweden)

    Tuuli Lahti

    2010-01-01

    Full Text Available Circadian rhythm disruptions may have harmful impacts on health. Circadian rhythm disruptions caused by jet lag compromise the quality and amount of sleep and may lead to a variety of symptoms such as fatigue, headache, and loss of attention and alertness. Even a minor change in time schedule may cause considerable stress for the body. Transitions into and out of daylight saving time alter the social and environmental timing twice a year. According to earlier studies, this change in time-schedule leads to sleep disruption and fragmentation of the circadian rhythm. Since sleep deprivation decreases motivation, attention, and alertness, transitions into and out of daylight saving time may increase the amount of accidents during the following days after the transition. We studied the amount of road traffic accidents one week before and one week after transitions into and out of daylight saving time during years from 1981 to 2006. Our results demonstrated that transitions into and out of daylight saving time did not increase the number of traffic road accidents.

  18. Phase transition time delays in irradiated superheated superconducting granules

    CERN Document Server

    Abplanalp, M; Czapek, G; Diggelmann, U; Furlan, M; Gabutti, A; Janos, S; Moser, U; Pozzi, R; Pretzl, Klaus P; Schmiemann, K; Perret-Gallix, D; Van den Brandt, B; Konter, J A; Mango, S

    1994-01-01

    The time difference between a particle interaction in a Superheated Superconducting Granule (SSG) and the resulting phase transition signal has been explored. Detectors containing Zn and Sn SSG were irradiated with neutrons and protons to study the heating mechanism taking place in nuclear recoil and ionizing events. Scattered neutrons have been detected by a scintillator hodoscope behind the SSG with a recoil energy measurement resolution of 10\\% and an interaction time resolution of 1ns. The fast transition of the metastable granules allowed to determine the elapsed time between an energy deposition and the phase transition signal. In the case of Sn granules, the results show that the time distributions are narrow and independent of the deposited energy in nuclear recoil and ionizing events. In Zn, however, the time distributions are much broader and depend on the energy deposition in the granule.

  19. Bisimulation and Open Maps for Timed Transition Systems

    DEFF Research Database (Denmark)

    Nielsen, Mogens

    1999-01-01

    framework of open maps. We define a category of timed transition systems, and show how to characterise standard timed bisimulation in terms of spans of open maps with a natural choice of a path category. This allows us to apply general results from the theory of open maps, e.g. the existence of canonical......Formal models for real-time systems have been studied intensively over the past decade. Much of the theory of untimed systems have been lifted to real-time settings. One example is the notion of bisimulation applied to timed transition systems, which is studied here within the general categorical...... models and characteristic logics. Also, we obtain here an alternative proof of decidability of bisimulation for finite transition systems, and illustrate the use of open maps in finite presentations of bisimulations...

  20. Establishment of a protocol for determining gastrointestinal transit time in mice using barium and radiopaque markers

    Energy Technology Data Exchange (ETDEWEB)

    Myagmarjaibuu, Bilomaa; Moon, Myeong Ju; Heo, Suk Hee; Jeong, Seo In; Jeong, Yong Yeon; Kang, Heoung Keun [Dept. of Radiology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Hwasun (Korea, Republic of); Park, Jong Seong [Dept. of Physiology, Chonnam National University Medical School, Gwangju (Korea, Republic of); Jun, Jae Yeoul [Dept. of Physiology, College of Medicine, Chosun University, Gwangju (Korea, Republic of)

    2013-01-15

    The purpose of this study was to establish a minimally invasive and reproducible protocol for estimating the gastrointestinal (GI) transit time in mice using barium and radiopaque markers. Twenty 5- to 6-week-old Balb/C female mice weighing 19-21 g were used. The animals were divided into three groups: two groups that received loperamide and a control group. The control group (n = 10) animals were administered physiological saline (1.5 mL/kg) orally. The loperamide group I (n = 10) and group II (n = 10) animals were administered 5 mg/kg and 10 mg/kg loperamide orally, respectively. Thirty minutes after receiving the saline or loperamide, the mice was administered 80 μL of barium solution and six iron balls (0.5 mm) via the mouth and the upper esophagus by gavage, respectively. Afterwards, the mice were continuously monitored with fluoroscopic imaging in order to evaluate the swallowing of the barium solution and markers. Serial fluoroscopic images were obtained at 5- or 10-min intervals until all markers had been excreted from the anal canal. For analysis, the GI transit times were subdivided into intestinal transit times (ITTs) and colon transit times (CTTs). The mean ITT was significantly longer in the loperamide groups than in the control group (p < 0.05). The mean ITT in loperamide group II (174.5 ± 32.3) was significantly longer than in loperamide group I (133.2 ± 24.2 minute) (p < 0.05). The mean CTT was significantly longer in loperamide group II than in the control group (p < 0.05). Also, no animal succumbed to death after the experimental procedure. The protocol for our study using radiopaque markers and barium is reproducible and minimally invasive in determining the GI transit time of the mouse model.

  1. Origin of time before inflation from a topological phase transition

    Science.gov (United States)

    Bellini, Mauricio

    2017-09-01

    We study the origin of the universe (or pre-inflation) by suggesting that the primordial space-time in the universe suffered a global topological phase transition, from a 4D Euclidean manifold to an asymptotic 4D hyperbolic one. We introduce a complex time, τ, such that its real part becomes dominant after started the topological phase transition. Before the big bang, τ is a space-like coordinate, so that can be considered as a reversal variable. After the phase transition is converted in a causal variable. The formalism solves in a natural manner the quantum to classical transition of the geometrical relativistic quantum fluctuations: σ, which has a geometric origin.

  2. Overexpression of forkhead Box C2 promotes tumor metastasis and indicates poor prognosis in colon cancer via regulating epithelial-mesenchymal transition.

    Science.gov (United States)

    Li, Qingguo; Wu, Jitao; Wei, Ping; Xu, Ye; Zhuo, Changhua; Wang, Yuwei; Li, Dawei; Cai, Sanjun

    2015-01-01

    Forkhead box protein C2 (FOXC2) plays a vital role in carcinogenesis; however, its significance and prognostic value in colon cancer remain unclear. In this study, FOXC2 expression was analyzed in a tissue microarray (TMA) containing 185 samples of primary colon cancer tumor samples and in human colon cancer cell lines. The effect of FOXC2 on cell proliferation, tumorigenesis, and metastasis was examined in vitro and in vivo. FOXC2 was overexpressed in human colon cancer cells and tissues, and correlated with colon cancer progression and patient survival. Functional study demonstrated that FOXC2 promoted cell growth, cell migration, and tumor formation in nude mice, whereas knockdown of FOXC2 by short hairpin RNA (shRNAs) significantly suppressed cell growth, cell migration and tumor formation. Further study found that FOXC2 enhanced AKT activity with subsequent GSK-3β phosphorylation and Snail stabilization, and then induced epithelial-mesenchymal transition (EMT) and promoted tumor invasion and metastasis. Collectively, FOXC2 promotes colon cancer metastasis by facilitating EMT and acts as a potential prognostic factor and therapeutic target in colon cancer.

  3. TTVFaster: First order eccentricity transit timing variations (TTVs)

    Science.gov (United States)

    Agol, Eric; Deck, Katherine

    2016-04-01

    TTVFaster implements analytic formulae for transit time variations (TTVs) that are accurate to first order in the planet-star mass ratios and in the orbital eccentricities; the implementations are available in several languages, including IDL, Julia, Python and C. These formulae compare well with more computationally expensive N-body integrations in the low-eccentricity, low mass-ratio regime when applied to simulated and to actual multi-transiting Kepler planet systems.

  4. High-Cadence Transit Timing Variation Monitoring of Extrasolar Planets

    Directory of Open Access Journals (Sweden)

    Naef D.

    2011-02-01

    Full Text Available We report ground-based high-cadence transit timing observations of the extrasolar planet WASP-2b. We achieve a typical timing error of 15-30 sec. The data show no significant deviations from the predicted ephemeris.

  5. Modelling systematics of ground-based transit photometry I. Implications on transit timing variations

    DEFF Research Database (Denmark)

    von Essen, C.; Cellone, S.; Mallonn, M.

    2016-01-01

    the observing time at hand carrying out such follow-ups, or if the use of medium-to-low quality transit light curves, combined with current standard techniques of data analysis, could be playing a main role against exoplanetary search via TTVs. The purpose of this work is to investigate to what extent ground...... we attempt to reproduce, by means of physically and empirically motivated relationships, the effects caused by the Earth's atmosphere and the instrumental setup on the synthetic light curves. Therefore, the synthetic data present different photometric quality and transit coverage. In addition, we...... introduced a perturbation in the mid-transit times of the hot Jupiter, caused by an Earth-sized planet in a 3:2 mean motion resonance. Analyzing the synthetic light curves produced after certain epochs, we attempt to recover the synthetically added TTV signal by means of usual primary transit fitting...

  6. Reference values for the geometric centre analysis of colonic transit measurements with 111indium-labelled diethylenetriamine penta-acetic acid

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Fuglsang, Stefan; Graff, Jesper

    2003-01-01

    The geometric centre analysis is often used for evaluating colonic transit data obtained by scintigraphy after oral intake of 111indium-labelled diethylenetriamine penta-acetic acid (111In-DTPA). The purpose of this study was to establish reference values for the geometric centre analysis in adult...

  7. Reference values for the geometric centre analysis of colonic transit measurements with 111indium-labelled diethylenetriamine penta-acetic acid

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Fuglsang, Stefan; Graff, Jesper

    2003-01-01

    The geometric centre analysis is often used for evaluating colonic transit data obtained by scintigraphy after oral intake of 111indium-labelled diethylenetriamine penta-acetic acid (111In-DTPA). The purpose of this study was to establish reference values for the geometric centre analysis in adult...

  8. Mean Transit Time and Mean Residence Time for Linear Diffusion–Convection–Reaction Transport System

    Directory of Open Access Journals (Sweden)

    Jacek Waniewski

    2007-01-01

    Full Text Available Characteristic times for transport processes in biological systems may be evaluated as mean transit times (MTTs (for transit states or mean residence times (MRT (for steady states. It is shown in a general framework of a (linear reaction–diffusion–convection equation that these two times are related. Analytical formulas are also derived to calculate moments of exit time distribution using solutions for a stationary state of the system.

  9. Development of time and pH dependent controlled release colon specific delivery of tinidazole

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Purpose: Tinidazole is used in treatment of amoebiasis and other protozoal infections in doses of 2.0 g/ day (60 mg/kg for three days. In the present paper, controlled release formulation of tinidazole was developed with an objective to achieve colon specific drug delivery with reduced frequency of dosing, to minimize gastric side effects and thus to increase patient compliance. Methods: Matrix systems of tinidazole (500 mg were prepared by using swellable and pH dependent polymers like hydroxypropyl methylcellulose (HPMC K4M and K15M and eudragit (eudragit L-100 and S-100. Prepared tablets were enteric coated in order to overcome variability in gastric emptying time and delay in the release, to reduce gastric side effects and to provide prolonged localized action in colon. Process of manufacture was optimized during the scale up studies. Bioavailability study (using parallel group design was carried of on conventional marketed, developed uncoated and enteric coated tablets in healthy human volunteers. Results: Bioavailability study showed that greater portion of tinidazole was released in the large intestine and drug level in plasma was above 4 mg/mL in blood for 24 hours. Conclusion: From the results of this study it appears that, the proposed single enteric coated tinidazole (500 mg tablet per day could be used in place of 3-4 doses of 500 mg tinidazole conventional tablet with better control of drug release for targeted drug delivery. In addition developed colon-specific drug delivery system (CDDS was relatively inexpensive and easy to manufacture using conventional pharmaceutical coating technique.

  10. Transition in adolescents across time, disease and gender

    DEFF Research Database (Denmark)

    Svanholm, Jette Rolf; Ludvigsen, Mette Spliid; Aagaard, Hanne

    Transition in adolescents across time, disease and gender Jette Rolf Svanholm 1,2, Mette Spliid Ludvigsen 1,3, Hanne Aagaard 1,4,5 1 Aarhus University Hospital, Denmark 2 Department of Cardiology 3 Department of Renal Medicine 4 Department of Pediatrics 5 Institute of Public Health, Aarhus...... of transition being in a maturing and independence process and what is important to them? • What characterise their interaction with health care staff? • How is the communication between the adolescents and health care staff as perceived by the adolescents when focus is on their illness? Methods: Qualitative...... central characteristics across time, disease and gender. Perspectives It is expected that this study will create knowledge about the existential and interpersonal challenges of adolescents in transition as seen from the • time perspective • diagnose perspective • gender perspective These results will make...

  11. Simplified assessment of segmental gastrointestinal transit time with orally small amount of barium

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Weitang; Zhang, Zhiyong; Liu, Jinbo; Li, Zhen; Song, Junmin; Wu, Changcai [Department of Colorectal Surgery, The First Affiliated Hospital and Institute of Clinical Medicine, Zhengzhou University, 450052 Zhengzhou (China); Wang, Guixian, E-mail: guixianwang@hotmail.com [Department of Colorectal Surgery, The First Affiliated Hospital and Institute of Clinical Medicine, Zhengzhou University, 450052 Zhengzhou (China)

    2012-09-15

    Objective: To determine the effectiveness and advantage of small amount of barium in the measurement of gastrointestinal transmission function in comparison with radio-opaque pallets. Methods: Protocal 1: 8 healthy volunteers (male 6, female 2) with average age 40 ± 6.1 were subjected to the examination of radio-opaque pellets and small amount of barium with the interval of 1 week. Protocol 2: 30 healthy volunteers in group 1 (male 8, female 22) with average age 42.5 ± 8.1 and 50 patients with chronic functional constipation in group 2 (male 11, female 39) with average age 45.7 ± 7.8 were subjected to the small amount of barium examination. The small amount of barium was made by 30 g barium dissolved in 200 ml breakfast. After taking breakfast which contains barium, objectives were followed with abdominal X-ray at 4, 8, 12, 24, 48, 72, 96 h until the barium was evacuated totally. Results: Small amount of barium presented actual chyme or stool transit. The transit time of radio-opaque pallets through the whole gastrointestinal tract was significantly shorter than that of barium (37 ± 8 h vs. 47 ± 10 h, P < 0.05) in healthy people. The transit times of barium in constipation patients were markedly prolonged in colon (61.1 ± 22 vs. 37.3 ± 11, P < 0.01) and rectum (10.8 ± 3.7 vs. 2.3 ± 0.8 h, P < 0.01) compared with unconstipated volunteers. Transit times in individual gastrointestinal segments were also recorded by using small amount of barium, which allowed identifying the subtypes of constipation. Conclusion: The small amount barium examination is a convenient and low cost method to provide the most useful and reliable information on the transmission function of different gastrointestinal segments and able to classify the subtypes of slow transit constipation.

  12. Dual-Priced Modal Transition Systems with Time Durations

    DEFF Research Database (Denmark)

    Beneš, Nikola; Kretínsky, Jan; Larsen, Kim Guldstrand

    2012-01-01

    Modal transition systems are a well-established specification formalism for a high-level modelling of component-based software systems. We present a novel extension of the formalism called modal transition systems with durations where time durations are modelled as controllable or uncontrollable...... intervals. We further equip the model with two kinds of quantitative aspects: each action has its own running cost per time unit, and actions may require several hardware components of different costs. We ask the question, given a fixed budget for the hardware components, what is the implementation...

  13. Postfoundational practical theology for a time of transition

    Directory of Open Access Journals (Sweden)

    Julian C. Müller

    2011-06-01

    Full Text Available In reflection on the question as to in what sense is our time a time of transition, the article explores the various transitions in epistemology, advocated by the scholars mentioned in brackets:• modern to postmodern • secular dualism to post-secular holism (Cornel du Toit • structural to poststructural • positivistic to relativistic • rational-argumentative to narrative • proposisionalistic to cultural-linguistic (Lindbeck • fundamentalist to postfoundationalist (Schrag and Van Huyssteen • maintenance to missional.

  14. Noise-induced transition in human reaction times

    Science.gov (United States)

    Medina, José M.; Díaz, José A.

    2016-09-01

    The human reaction/response time can be defined as the time elapsed from the onset of stimulus presentation until a response occurs in many sensory and cognitive processes. A reaction time model based on Piéron’s law is investigated. The model shows a noise-induced transition in the moments of reaction time distributions due to the presence of strong additive noise. The model also demonstrates that reaction times do not follow fluctuation scaling between the mean and the variance but follow a generalized version between the skewness and the kurtosis. The results indicate that noise-induced transitions in the moments govern fluctuations in sensory-motor transformations and open an insight into the macroscopic effects of noise in human perception and action. The conditions that lead to extreme reaction times are discussed based on the transfer of information in neurons.

  15. The scintigraphic determination of small intestinal transit time in patients with irritable bowel syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Marano, A.R.; Caride, V.J.; Shah, R.V.; Prokop, E.K.; Troncale, F.J.; McCallum, R.W.

    1984-01-01

    Diffuse disturbance in gastrointestinal motility may be present in patients with irritable bowel syndrome (IBS). To further investigate small intestinal motility in IBS patients small intestinal transit time (SITT) was determined and related to the symptom status. 11 female patients with IBS (mean age 29 years) were divided into those whose predominate symptom was diarrhea (N=6), and those with only constipation (N=5). All subjects ingested an isosmotic solution of lactulose (10 gm in 150cc of water) labeled with 99m-Tc-DTPA (Sn). The patient was studied supine under a 25 inch gamma camera with data collected at 1 frame per minute for 180 minutes or until activity appeared in the ascending colon. Regions of interest were selected over the cecum and ascending colon. The time of first appearance of radioactivity in the region of the cecum was taken as the small intestinal transit time. SITT in the 5 normal females was 98.7 +- 13 min (mean +- SEM). SITT in the IBS patients with diarrhea, 67.3 +- 7 min was significantly faster (p< 0.08). SITT in the constipated IBS patients, 126 +- 12 min, was slower than normals and significantly different from diarrhea patients (p< 0.001). These studies show that IBS patients with diarrhea have significantly faster SITT than normals while constipated IBS patients have significantly slower SITT than the diarrhea subgroup. Further, this study emphasizes the need to study the various symptomatic subgroups of IBs patients independently and indicates a possible role for abnormal SITT in the pathogenesis of IBS.

  16. Transit Timing Variations for Eccentric and Inclined Exoplanets

    Science.gov (United States)

    Nesvorný, David

    2009-08-01

    The Transit Timing Variation (TTV) method relies on monitoring changes in timing of transits of known exoplanets. Nontransiting planets in the system can be inferred from TTVs by their gravitational interactions with the transiting planet. The TTV method is sensitive to low-mass planets that cannot be detected by other means. Inferring the orbital elements and mass of the nontransiting planets from TTVs, however, is more challenging than for other planet detection schemes. It is a difficult inverse problem. Here, we extended the new inversion method proposed by Nesvorný & Morbidelli to eccentric transiting planets and inclined orbits. We found that the TTV signal can be significantly amplified for hierarchical planetary systems with substantial orbital inclinations and/or for an eccentric transiting planet with anti-aligned orbit of the planetary companion. Thus, a fortuitous orbital setup of an exoplanetary system may significantly enhance our chances of TTV detection. We also showed that the detailed shape of the TTV signal is sensitive to the orbital inclination of the nontransiting planetary companion. The TTV detection method may thus provide important constraints on the orbital inclination of exoplanets and be used to test theories of planetary formation and evolution.

  17. The liner shipping berth scheduling problem with transit times

    DEFF Research Database (Denmark)

    Reinhardt, Line Blander; Plum, Christian E.M.; Pisinger, David

    2016-01-01

    In this paper speed optimization of an existing liner shipping network is solved by adjusting the port berth times. The objective is to minimize fuel consumption while retaining the customer transit times including the transhipment times. To avoid too many changes to the time table, changes of port...... berth times are only accepted if they lead to savings above a threshold value. Since the fuel consumption of a vessel is a non-linear convex function of the speed, it is approximated by a piecewise linear function. The developed model is solved using exact methods in less than two minutes for large...

  18. Transition paths out of part-time unemployment

    OpenAIRE

    Månsson, Jonas; Ottoson, Jan

    2010-01-01

    Using a rich data set on all registered Swedish part-time unemployed in 2003 we aim at identify individual characteristics that affect the probability of leaving part-time unemployment—from the perspective of whether part-time work serves as a transition mechanism offering access to the core labour market of full-time jobs, a stepping stone to the labour market, or if it is a dead end. The results of the study indicate clearly that there are groups for whom part-time employment cannot be cons...

  19. Room acoustic transition time based on reflection overlap

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Brunskog, Jonas; Jacobsen, Finn

    2010-01-01

    A transition time is defined based on the temporal overlap of reflected pulses in room impulse responses. Assuming specular reflections only, the temporal distance between adjacent reflections, which is proportional to the volume of a room, is compared with the characteristic width of a pulse...

  20. Room acoustic transition time based on reflection overlap

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Brunskog, Jonas; Jacobsen, Finn

    2013-01-01

    A transition time is defined based on the temporal overlap of reflected pulses in room impulse responses. Assuming specular reflections only, the temporal distance between adjacent reflections, which is proportional to the volume of a room, is compared with the characteristic width of a pulse...

  1. Reference values for the geometric centre analysis of colonic transit measurements with 111indium-labelled diethylenetriamine penta-acetic acid

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Fuglsang, Stefan; Graff, Jesper

    2003-01-01

    The geometric centre analysis is often used for evaluating colonic transit data obtained by scintigraphy after oral intake of 111indium-labelled diethylenetriamine penta-acetic acid (111In-DTPA). The purpose of this study was to establish reference values for the geometric centre analysis in adult...... humans. Forty-eight healthy volunteers (24 women, 24 men) who were equally distributed among three age groups (young, middle-aged, elderly) were studied. In all subjects the geometric centre of radioactivity in the colon was calculated from abdominal gamma camera images acquired 24, 48, 72, and 96 h...

  2. The Transiting System GJ1214: High-Precision Defocused Transit Observations and a Search for Evidence of Transit Timing Variation

    DEFF Research Database (Denmark)

    Harpsøe, Kennet Bomann West; Hardis, S.; Hinse, T. C.

    2012-01-01

    : The observations are used to determine the photometric parameters and the physical properties of the GJ1214 system. Our results are in good agreement with published values. Individual times of mid-transit are measured with uncertainties as low as 10s, allowing us to reduce the uncertainty in the orbital period...

  3. Visual Analysis and Comparison of Kepler Transit Timing Variations with Mutli-Transiting System Applications

    Science.gov (United States)

    Kane, Mackenzie; Ragozzine, Darin; Flowers, Xzavier

    2016-10-01

    By noticing the dimming and brightening of the star as an exoplanet transit occurs, NASA's Kepler Space Telescope records the times when the exoplanet passes in front of its star. If other planets are gravitationally influencing the transiting planet, the planet might transit late or early; these deviations from a perfectly periodic set of transits are called transit timing variations (TTVs). Therefore, Kepler TTVs have been very useful in determining exoplanet masses which can be hard to measure in other ways.We visually analyzed the TTV data of all ~6000 Kepler objects of interest (KOIs) to determine whether interesting TTV signals would be missed by purely statistical analyses. Using data from Rowe et al. 2014 and Holczer et al. 2016, we examined TTV plots, periodograms, and folded quadratic+sinusoid fits. To find the most likely KOIs containing visible TTVs and to organize the over 6000 KOIs analyzed, a rating system was developed based on numerous visual factors. By sorting KOIs as such, we were able to compare our findings of the strongest candidates with the same KOIs statistically analyzed by Holczer et al. 2016. It was found that the majority of our findings matched those of Holczer et al. 2016, with only small discrepancies that were understandable based on our different methodologies. Still, our visual inspection of the full list of KOIs contributed multiple planets that were not identified statistically.We combined all of these results with planet properties from the NASA Exoplanet Archive, confirmed and cumulative, to investigate the demographics of planetary systems with and without TTVs. We investigated multi-transiting systems with TTVs not attributable to any of the known planets in the system to better understand exoplanetary system architectures in cases where not all of the planets are transiting.

  4. The Effect of Electro-acupuncture in Different Depths on Colonic Transit Time of Patients with Slow Transmit Constipation%电针“天枢穴”不同深度刺激对慢传输型功能性便秘患者结肠转运时间的影响

    Institute of Scientific and Technical Information of China (English)

    何洪波; 李宁; 王成伟; 吕建琴

    2011-01-01

    Objective: To compare the effect of electro - acupuncture Tianshu (ST25) in different depths on co-Ionic transit time(CTT). Methods ;Fourty patients were selected and divided into two groups at random (The patients in group A were deeply electro - acupuncture bilateral Tianshu points, while ones in group B were shal-lowly electro - punctrued bilateral Tianshu points ) . The course of treatment was 4 weeks. The CTTs of two groups after treatment and the time difference of CTT before and after treatment in two groups were evaluated and compared. Results: Significant difference in CTT after treatment was found in neither group (P >0.05) ,but it was found in the time difference of CTT before and after treatment in both groups(P <0. 05). Besides,inserting through membrana abdominis was more effective in improving the time difference of CTT before and after treatment than that just in the hypoderm ( P < 0. 05), which showed electro - acupuncture Tianshu deeply worked effectively than doing shallowly. There were not any electro - acupuncture accidents happening in the trials. Conclusion-.Electro -acupuncture Tianshu point(ST25) deeply was able to shorten CTT more effectively, moreover,it was safe.%目的:比较电针“天枢穴”不同的深度刺激对全结肠转运时间的影响。方法:采用随机对照试研究方法将纳入的40例患者,随机分为A组(电针深刺双侧天枢穴组)与B组(电针浅刺双侧天枢穴组)。治疗4周后评估两组全结肠转运时间及比较治疗前后全结肠转运时间差值变化。结果:尽管两组电针天枢穴刺激治疗后全结肠转运时间比较差异无显著意义(P>0.05),但两组治疗后相较于各自组治疗前全结肠转运时间比较均有明显改善,差异有统计学意义(P<0.05)。且电针突破腹膜深刺组较仅皮下浅刺组就治疗前后改善全结肠转运时间的差值上更有效(P<0.05),提示深刺治疗改善全结肠转运时间效率更佳。整

  5. Transition in adolescents across time, disease and gender

    DEFF Research Database (Denmark)

    Aagaard, Hanne; Ludvigsen, Mette Spliid; Svanholm, Jette Rolf

    Background: Despite a growing number of studies on transition to adulthood in adolescents, literature is scarce on qualitative, longitudinal studies of transitions in adolescents with severe chronic diseases. The aim is to study transition in adolescents with cystic fibrosis, congenital heart......: This is a longitudinal ethnographic study running from 2012 to 2017. Adolescents are consecutively included at the age between 13 and 14, 8-10 participants in each group. The fieldwork is based on participant observation of consultations between the adolescent and healthcare professionals and individual qualitative...... interview with the adolescent at outpatient clinics at Aarhus University Hospital. Follow-up is planned at 15 and 18 years of age. A comparative approach is employed to show central characteristics across time, disease and gender. Results: Results from analysis inspired by Ricoeur's phenomenological...

  6. Time delay between cardiac and brain activity during sleep transitions

    Science.gov (United States)

    Long, Xi; Arends, Johan B.; Aarts, Ronald M.; Haakma, Reinder; Fonseca, Pedro; Rolink, Jérôme

    2015-04-01

    Human sleep consists of wake, rapid-eye-movement (REM) sleep, and non-REM (NREM) sleep that includes light and deep sleep stages. This work investigated the time delay between changes of cardiac and brain activity for sleep transitions. Here, the brain activity was quantified by electroencephalographic (EEG) mean frequency and the cardiac parameters included heart rate, standard deviation of heartbeat intervals, and their low- and high-frequency spectral powers. Using a cross-correlation analysis, we found that the cardiac variations during wake-sleep and NREM sleep transitions preceded the EEG changes by 1-3 min but this was not the case for REM sleep transitions. These important findings can be further used to predict the onset and ending of some sleep stages in an early manner.

  7. Transition in adolescents across time, disease and gender

    DEFF Research Database (Denmark)

    Svanholm, Jette Rolf; Ludvigsen, Mette Spliid; Aagaard, Hanne

    Transition in adolescents across time, disease and gender Jette Rolf Svanholm 1,2, Mette Spliid Ludvigsen 1,3, Hanne Aagaard 1,4,5 1 Aarhus University Hospital, Denmark 2 Department of Cardiology 3 Department of Renal Medicine 4 Department of Pediatrics 5 Institute of Public Health, Aarhus...... University, Denmark Jeanette.Svanholm@skejby.rm.dk, Mette.Ludvigsen@skejby.rm.dk, Hanne.Aagaard@skejby.rm.dk Background: Adolescents do not get involved in the preparation and planning of their health care transition, which leaves them with negative experiences and feelings of not having their health care......’ with congenial heart diseases, chronic kidney diseases and cystic fibrosis perspective. Objective: To study experiences of transition in adolescents with severe chronic diseases in the context of child-centred health care to adult-centred health care Research questions: • What are the adolescents’ experiences...

  8. Transition in adolescents across time, disease and gender

    DEFF Research Database (Denmark)

    Aagaard, Hanne; Ludvigsen, Mette Spliid; Svanholm, Jette Rolf

    interview with the adolescent at outpatient clinics at Aarhus University Hospital. Follow-up is planned at 15 and 18 years of age. A comparative approach is employed to show central characteristics across time, disease and gender. Results: Results from analysis inspired by Ricoeur's phenomenological......Background: Despite a growing number of studies on transition to adulthood in adolescents, literature is scarce on qualitative, longitudinal studies of transitions in adolescents with severe chronic diseases. The aim is to study transition in adolescents with cystic fibrosis, congenital heart...... diseases and chronic kidney diseases. We specifically focus on the adolescents’ experiences, 'what is important to them', 'what characterises their interaction with health care staff' and 'the communication between the adolescents and health care staff as perceived by the adolescents'. Methods...

  9. Colon-targeted delivery of budesonide using dual pH- and time-dependent polymeric nanoparticles for colitis therapy

    Directory of Open Access Journals (Sweden)

    Naeem M

    2015-07-01

    Full Text Available Muhammad Naeem,1 Moonjeong Choi,1 Jiafu Cao,1 Yujeong Lee,1 Muhammad Ikram,2 Sik Yoon,2 Jaewon Lee,1 Hyung Ryong Moon,1 Min-Soo Kim,1 Yunjin Jung,1 Jin-Wook Yoo11College of Pharmacy, Pusan National University, Busan, 2Pusan National University School of Medicine, Yangsan, South KoreaAbstract: Single pH-dependent drug delivery systems have been widely used for colon-targeted delivery, but their efficiency is often hampered by the variation in gut pH. To overcome the limitation of single pH-dependent delivery systems, in this study, we developed and evaluated the therapeutic potential of budesonide-loaded dual pH/time-dependent nanoparticles (NPs for the treatment of colitis. Eudragit FS30D was used as a pH-dependent polymer, and Eudragit RS100 as a time-dependent controlled release polymer. Single pH-dependent NPs (pH_NPs, single time-dependent NPs (Time_NPs, and dual pH/time-dependent NPs (pH/Time_NPs were prepared using the oil-in-water emulsion method. The physicochemical properties and drug release profiles of these NPs in gastrointestinal (GI tract conditions were investigated. The therapeutic potential and in vivo distribution of the NPs were evaluated in a dextran sulfate sodium (DSS-induced colitis mice model. The pH/Time_NPs prevented a burst drug release in acidic pH conditions and showed sustained release at a colonic pH. The in vivo distribution study in the mice GI tract demonstrated that pH/Time_NPs were more efficiently delivered to the inflamed colon than pH_NPs were. Compared to the single pH_NPs-treated group, the pH/Time_NPs-treated group showed increased body weight and colon length and markedly decreased disease activity index, colon weight/length ratios, histological damage, and inflammatory cell infiltration in colon tissue. Our results demonstrate that the dual pH/time-dependent NPs are an effective oral colon-targeted delivery system for colitis therapy.Keywords: colon-specific delivery, dual-sensitive delivery

  10. Capsule endoscopy: Improving transit time and image view

    Institute of Scientific and Technical Information of China (English)

    Zvi Fireman; D Paz; Y Kopelman

    2005-01-01

    AIM: To evaluate the effect of various methods of small bowel preparation on the transit time and the quality of visualization of the entire small bowel mucosa.METHODS: Ninety-five patients underwent capsule endoscopy (CE) by easily swallowing the capsule. They were divided into three study groups according to the preparation used: group A (n = 26) by polyethylene glycol (PEG) liter or with sodium phosphate (SP) 12 h prior to the CE study; group B (n = 29) by erythromycin 1 h prior to the CE study; and group C (n = 40) without any preparation. Visualization ranged from good to satisfactory to poor.RESULTS: The gastric emptying time in the group prepared with erythromycin was shorter but without statistical significance and the small bowel transit time was unaffected. In elderly subjects prepared by PEG or SP, the gastric emptying time was significantly longer (163.7 min, P = 0.05). The transit times of the three sub-groups were not affected by gender or pathology.The grade of cleaning of the entire study group was 3.27±1.1. The erythromycin group presented significantly the worst quality of images (P = 0.05) compared to the other sub-groups. Age, gender, and pathology had no effect on the quality of the cleaning of the small bowel in the sub-groups. One (1.05%) case had no natural excretion.CONCLUSION: Erythromycin markedly reduces gastric emptying time, but has a negative effect on the quality of the image in the small bowel. The preparation of elderly subjects with PEG or SP has a negative effect on the small bowel transit time.

  11. Electron transit time measurements of 5-in photomultiplier tubes

    Science.gov (United States)

    Richards, T.; Peatross, J.; Ware, M.; Rees, L.

    2016-08-01

    We investigated the uniformity of electron transit times for two 5-in photomultiplier tubes: the Hamamatsu R1250 and the Adit B133D01S. We focused a highly attenuated short-pulse laser on the tubes while they were mounted on a programmable stage. The stage translated the tubes relative to the incident beam so that measurements could be made with light focused at points along a grid covering the entire photocathodes. A portion of the incident light was split from the incident beam and measured and recorded by a fast photodiode. Electron transit times were measured by computing the time delay between the recorded photodiode signal and photomultiplier signal using software constant-fraction discrimination. The Hamamatsu tube exhibited a uniform timing response that varied by no more than 1.7 ns. The Adit tube was much less uniform, with transit times that varied by as much as 57 ns. The Adit response also exhibited a spatially varying double-peak structure in its response. The technique described in this paper could be usefully employed by photomultiplier tube manufacturers to characterize the performance of their products.

  12. Integrated response and transit time distributions of watersheds by combining hydrograph separation and long-term transit time modeling

    Directory of Open Access Journals (Sweden)

    M. C. Roa-García

    2010-08-01

    Full Text Available We present a new modeling approach analyzing and predicting the Transit Time Distribution (TTD and the Response Time Distribution (RTD from hourly to annual time scales as two distinct hydrological processes. The model integrates Isotope Hydrograph Separation (IHS and the Instantaneous Unit Hydrograph (IUH approach as a tool to provide a more realistic description of transit and response time of water in catchments. Individual event simulations and parameterizations were combined with long-term baseflow simulation and parameterizations; this provides a comprehensive picture of the catchment response for a long time span for the hydraulic and isotopic processes. The proposed method was tested in three Andean headwater catchments to compare the effects of land use on hydrological response and solute transport. Results show that the characteristics of events and antecedent conditions have a significant influence on TTD and RTD, but in general the RTD of the grassland dominated catchment is concentrated in the shorter time spans and has a higher cumulative TTD, while the forest dominated catchment has a relatively higher response distribution and lower cumulative TTD. The catchment where wetlands concentrate shows a flashier response, but wetlands also appear to prolong transit time.

  13. Integrated response and transit time distributions of watersheds by combining hydrograph separation and long-term transit time modeling

    Directory of Open Access Journals (Sweden)

    M. C. Roa-García

    2010-01-01

    Full Text Available We present a new modeling approach analyzing and predicting the Transit Time Distribution (TTD and the Response Time Distribution (RTD from hourly to annual time scales as two distinct hydrological processes. The model integrates Isotope Hydrograph Separation (IHS and the Instantaneous Unit Hydrograph (IUH approach as a tool to provide a more realistic description of transit and response time of water in catchments. Individual event simulations and parameterizations were combined with long-term baseflow simulation and parameterizations to provide a comprehensive picture of the catchment response for a long time span for the hydraulic and isotopic processes. The proposed method was tested in three Andean headwater catchments to compare the effects of land use on hydrological response and solute transport. Results show that the characteristics of events and antecedent conditions have a significant influence on TTD and RTD, but in general the RTD of the grassland dominated catchment is concentrated in the shorter time spans and has a higher cumulative TTD, while the forest dominated catchment has a relatively longer response distribution and lower cumulative TTD. The catchment where wetlands concentrate shows a flashier response, but wetlands also appear to contribute to prolong transit time.

  14. Taste and Temperature in Swallowing Transit Time after Stroke

    Directory of Open Access Journals (Sweden)

    Paula C. Cola

    2012-09-01

    Full Text Available Background: Oropharyngeal dysphagia is common in individuals after stroke. Taste and temperature are used in dysphagia rehabilitation. The influence of stimuli, such as taste and temperature, on swallowing biomechanics has been investigated in both healthy individuals and in individuals with neurological disease. However, some questions still remain unanswered, such as how the sequence of offered stimuli influences the pharyngeal response. The goal of the present study was to determine the influence of the sequence of stimuli, sour taste and cold temperature, on pharyngeal transit time during deglutition in individuals after stroke. Methods: The study included 60 individuals with unilateral ischemic stroke, 29 males and 31 females, aged 41–88 years (mean age: 66.2 years examined 0–50 days after ictus (median: 6 days, with mild to moderate oropharyngeal dysphagia. Exclusion criteria were hemorrhagic stroke patients, patients with decreased level of consciousness, and clinically unstable patients, as confirmed by medical evaluation. The individuals were divided into two groups of 30 individuals each. Group 1 received a nonrandomized sequence of stimuli (i.e. natural, cold, sour, and sour-cold and group 2 received a randomized sequence of stimuli. A videofluoroscopic swallowing study was performed to analyze the pharyngeal transit time. Four different stimuli (natural, cold, sour, and sour-cold were offered. The images were digitalized and specific software was used to measure the pharyngeal transit time. Since the values did not present regular distribution and uniform variances, nonparametric tests were performed. Results: Individuals in group 1 presented a significantly shorter pharyngeal transit time with the sour-cold stimulus than with the other stimuli. Individuals in group 2 did not show a significant difference in pharyngeal transit time between stimuli. Conclusions: The results showed that the sequence of offered stimuli influences

  15. Multiplex real time PCR panels to identify fourteen colonization factors of enterotoxigenic Escherichia coli (ETEC).

    Science.gov (United States)

    Liu, Jie; Silapong, Sasikorn; Jeanwattanalert, Pimmada; Lertsehtakarn, Paphavee; Bodhidatta, Ladaporn; Swierczewski, Brett; Mason, Carl; McVeigh, Annette L; Savarino, Stephen J; Nshama, Rosemary; Mduma, Esto; Maro, Athanasia; Zhang, Jixian; Gratz, Jean; Houpt, Eric R

    2017-01-01

    Enterotoxigenic Escherichia coli (ETEC) is a leading cause of childhood diarrhea in low income countries and in travelers to those areas. Inactivated enterotoxins and colonization factors (CFs) are leading vaccine candidates, therefore it is important to determine the prevailing CF types in different geographic locations and populations. Here we developed real time PCR (qPCR) assays for 14 colonization factors, including the common vaccine targets. These assays, along with three enterotoxin targets (STh, STp, and LT) were formulated into three 5-plex qPCR panels, and validated on 120 ETEC isolates and 74 E. coli colony pools. The overall sensitivity and specificity was 99% (199/202) and 99% (2497/2514), respectively, compared to the CF results obtained with conventional PCR. Amplicon sequencing of discrepant samples revealed that the qPCR was 100% accurate. qPCR panels were also performed on nucleic acid extracted from stool and compared to the results of the ETEC isolates or E. coli colony pools cultured from them. 95% (105/110) of the CF detections in the cultures were confirmed in the stool. Additionally, direct testing of stool yielded 30 more CF detections. Among 74 randomly selected E. coli colony pools with paired stool, at least one CF was detected in 63% (32/51) of the colony pools while at least one CF was detected in 78% (47/60) of the stool samples (P = NS). We conclude that these ETEC CF assays can be used on both cultures and stool samples to facilitate better understanding of CF distribution for ETEC epidemiology and vaccine development.

  16. The colonization of land by animals: molecular phylogeny and divergence times among arthropods

    Directory of Open Access Journals (Sweden)

    Lyons-Weiler Maureen

    2004-01-01

    Full Text Available Abstract Background The earliest fossil evidence of terrestrial animal activity is from the Ordovician, ~450 million years ago (Ma. However, there are earlier animal fossils, and most molecular clocks suggest a deep origin of animal phyla in the Precambrian, leaving open the possibility that animals colonized land much earlier than the Ordovician. To further investigate the time of colonization of land by animals, we sequenced two nuclear genes, glyceraldehyde-3-phosphate dehydrogenase and enolase, in representative arthropods and conducted phylogenetic and molecular clock analyses of those and other available DNA and protein sequence data. To assess the robustness of animal molecular clocks, we estimated the deuterostome-arthropod divergence using the arthropod fossil record for calibration and tunicate instead of vertebrate sequences to represent Deuterostomia. Nine nuclear and 15 mitochondrial genes were used in phylogenetic analyses and 61 genes were used in molecular clock analyses. Results Significant support was found for the unconventional pairing of myriapods (millipedes and centipedes with chelicerates (spiders, scorpions, horseshoe crabs, etc. using nuclear and mitochondrial genes. Our estimated time for the divergence of millipedes (Diplopoda and centipedes (Chilopoda was 442 ± 50 Ma, and the divergence of insects and crustaceans was estimated as 666 ± 58 Ma. Our results also agree with previous studies suggesting a deep divergence (~1100 – 900 Ma for arthropods and deuterostomes, considerably predating the Cambrian Explosion seen in the animal fossil record. Conclusions The consistent support for a close relationship between myriapods and chelicerates, using mitochondrial and nuclear genes and different methods of analysis, suggests that this unexpected result is not an artefact of analysis. We propose the name Myriochelata for this group of animals, which includes many that immobilize prey with venom. Our molecular clock

  17. Coupling of transit time instabilities in electrostatic confinement fusion devices

    Science.gov (United States)

    Gruenwald, J.; Fröhlich, M.

    2015-07-01

    A model of the behavior of transit time instabilities in an electrostatic confinement fusion reactor is presented in this letter. It is demonstrated that different modes are excited within the spherical cathode of a Farnsworth fusor. Each of these modes is dependent on the fusion products as well as the acceleration voltage applied between the two electrodes and they couple to a resulting oscillation showing non-linear beat phenomena. This type of instability is similar to the transit time instability of electrons between two resonant surfaces but the presence of ions and the occurring fusion reactions alter the physics of this instability considerably. The physics of this plasma instability is examined in detail for typical physical parameter ranges of electrostatic confinement fusion devices.

  18. Transit-Time Spin Field-Effect-Transistor

    OpenAIRE

    Appelbaum, Ian; Monsma, Douwe

    2007-01-01

    We propose and analyze a four-terminal metal-semiconductor device that uses hot-electron transport through thin ferromagnetic films to inject and detect a charge-coupled spin current transported through the conduction band of an arbitrary semiconductor. This provides the possibility of realizing a spin field-effect-transistor in Si, using electrostatic transit-time control in a perpendicular magnetic field, rather than Rashba effect with spin-orbit interaction.

  19. Estimation of liquid volume fraction using ultrasound transit time spectroscopy

    Science.gov (United States)

    Al-Qahtani, Saeed M.; Langton, Christian M.

    2016-12-01

    It has recently been proposed that the propagation of an ultrasound wave through complex structures, consisting of two-materials of differing ultrasound velocity, may be considered as an array of parallel ‘sonic rays’, the transit time of each determined by their relative proportion; being a minimum (t min) in entire higher velocity material, and a maximum (t max) in entire lower velocity material. An ultrasound transit time spectrum (UTTS) describes the proportion of sonic rays at an individual transit time. It has previously been demonstrated that the solid volume fraction of a solid:liquid composite, specifically acrylic step-wedges immersed in water, may be reliably estimated from the UTTS. The aim of this research was to investigate the hypothesis that the volume fraction of a two-component liquid mixture, of unequal ultrasound velocity, may also be estimated by UTTS. A through-transmission technique incorporating two 1 MHz ultrasound transducers within a horizontally-aligned cylindrical tube-housing was utilised, the proportion of silicone oil to water being varied from 0% to 100%. The liquid volume fraction was estimated from the UTTS at each composition, the coefficient of determination (R 2%) being 98.9  ±  0.7%. The analysis incorporated a novel signal amplitude normalisation technique to compensate for absorption within the silicone oil. It is therefore envisaged that the parallel sonic ray concept and the derived UTTS may be further applied to the quantification of liquid mixture composition assessment.

  20. Transit Timing Variations of Resonant Three-planet Systems

    Science.gov (United States)

    Libert, Anne-Sophie; Renner, S.

    2012-10-01

    The transit timing variations (TTV) method is a powerful technique to infer the existence of additional non-transiting planets. This is especially the case for resonant systems where the variations can be strongly enhanced. Here we focus on resonant 3-planet systems and assume that the inner body transits the star. We show that the TTV curve exhibits three periodicities related to the resonant evolution of the system. We perform a dynamical study for different mass values of the three planets, with a special attention to the detection of terrestrial planets. A very interesting result is that the existence of two terrestrial companions can be deduced from the TTV curve only. We also highlight the degeneracy in the characterization of non-transiting planets: a system of two giant planets in mean-motion resonance can hide a third terrestrial planet in a multi-resonant configuration. The work of A-S L is supported by an F.R.S.-FNRS Postdoctoral Research Fellowship.

  1. Transit Timing Observations from Kepler: VI. Transit Timing Variation Candidates in the First Seventeen Months from Polynomial Models

    CERN Document Server

    Ford, Eric B; Rowe, Jason F; Steffen, Jason H; Barclay, Thomas; Batalha, Natalie M; Borucki, William J; Bryson, Stephen T; Caldwell, Douglas A; Fabrycky, Daniel C; Gautier, Thomas N; Holman, Matthew J; Ibrahim, Khadeejah A; Kjeldsen, Hans; Kinemuchi, Karen; Koch, David G; Lissauer, Jack J; Still, Martin; Tenenbaum, Peter; Uddin, Kamal; Welsh, William

    2012-01-01

    Transit timing variations provide a powerful tool for confirming and characterizing transiting planets, as well as detecting non-transiting planets. We report the results an updated TTV analysis for 822 planet candidates (Borucki et al. 2011; Batalha et al. 2012) based on transit times measured during the first seventeen months of Kepler observations (Rowe et al 2012). We present 35 TTV candidates (4.1% of suitable data sets) based on long-term trends and 153 mostly weaker TTV candidates (18% of suitable data sets) based on excess scatter of TTV measurements about a linear ephemeris. We anticipate that several of these planet candidates could be confirmed and perhaps characterized with more detailed TTV analyses using publicly available Kepler observations. For many others, Kepler has observed a long-term TTV trend, but an extended Kepler mission will be required to characterize the system via TTVs. We find that the occurence rate of planet candidates that show TTVs is significantly increased (~60%-76%) for p...

  2. The time course of cytokine expressions plays a determining role in faster healing of intestinal and colonic anastomatic wounds

    Directory of Open Access Journals (Sweden)

    Ahmad M Zubaidi

    2015-01-01

    Full Text Available Objectives: Inflammation is critical in the early phases of wound healing. It has been reported previously that small intestinal and colonic wounds display a more rapid healing than those of other organs. However, the underlying mechanism has not yet been elucidated. Here we examined whether differences in the time course of specified cytokine expression, in colonic and small intestinal anastomotic lesions, might play a major role in this observation in comparison to lesions effecting skin and muscle tissue. Materials and Methods: Tissue lesions were applied to 36 male Sprague–Dawley rats. Tissue samples were harvested at 1, 3, 5, 7, and 14 days postoperatively with the levels of TNF-α, IL-6, and IFN-α determined by ELISA-derived methods. Results: The characteristics of TNF-α, IL-6, and IFN-α expression during the healing process for intestinal and colonic lesions were comparable. However, data differed significantly with that observed during healing of skin and muscle lesions. Intestinal and colonic lesions exhibited a significant and sustained increase in specified cytokine levels on day 5 to day 14 as compared with day 1 and 3. Skin and muscle lesions had random or unaltered cytokine levels throughout the study period. Conclusion: Differences in expression of cytokines TNF-α, IL-6, and IFN-α indicate that these play an important role underlying the more rapid healing processes observed in small intestinal and colonic lesions.

  3. Predicting the time to colonization of the parasitoid Diadegma semiclausum: the importance of the shape of spatial dispersal kernels for biological control

    NARCIS (Netherlands)

    Bianchi, F.J.J.A.; Schellhorn, N.A.; Werf, van der W.

    2009-01-01

    The time at which natural enemies colonize crop fields is an important determinant of their ability to suppress pest populations. This timing depends on the distance between source and sink habitats in the landscape. Here we estimate the time to colonization of sink habitats from a distant source ha

  4. Measurements of Transit Timing Variations for WASP-5b

    CERN Document Server

    Fukui, Akihiko; Tristram, Paul J; Sumi, Takahiro; Abe, Fumio; Itow, Yoshitaka; Sullivan, Denis J; Bond, Ian A; Hirano, Teruyuki; Tamura, Motohide; Bennett, David P; Furusawa, Kei; Hayashi, Fumiya; Hearnshaw, John B; Hosaka, Shun; Kamiya, Koki; Kobara, Shuhei; Korpela, Aarno; Kilmartin, Pam M; Lin, Wei; Ling, Cho Hong; Makita, Shota; Masuda, Kimiaki; Matsubara, Yutaka; Miyake, Noriyuki; Muraki, Yasushi; Nagaya, Maiko; Nishimoto, Kenta; Ohnishi, Kouji; Omori, Kengo; Perrott, Yvette; Rattenbury, Nicholas; Saito, Toshiharu; Skuljan, Ljiljana; Suzuki, Daisuke; Sweatman, Winston L; Wada, Kohei

    2010-01-01

    We have observed 7 new transits of the 'hot Jupiter' WASP-5b using a 61 cm telescope located in New Zealand, in order to search for transit timing variations (TTVs) which can be induced by additional bodies existing in the system. When combined with other available photometric and radial velocity (RV) data, we find that its transit timings do not match a linear ephemeris; the best fit \\chi^2 values of 32.2 with 9 degrees of freedom indicates that a marginal TTV signal has been observed at a confidence level of 99.982 %, or 3.7 \\sigma. The standard deviation of the TTVs is as large as 70 s, and if this is real, it cannot be explained by other effects than that due to an additional body or bodies. We put the upper limit on the RV amplitude due to the possible secondary body as 21 m s^{-1}, which corresponds to its mass of 22-70 M_{Earth} over the period ratio from 0.2 to 5.0. From the TTVs data, using the numerical simulations, we place more stringent limits down to 2 M_{Earth} near 1:2 and 2:1 MMRs at the 3 \\s...

  5. Detecting and Characterizing Planetary Systems with Transit Timing

    CERN Document Server

    Steffen, Jason H; Ford, Eric B; Agol, Eric; Holman, Matthew J

    2007-01-01

    In the coming decades, research in extrasolar planets aims to advance two goals: 1) detecting and characterizing low-mass planets increasingly similar to the Earth, and 2) improving our understanding of planet formation. We present a new planet detection method that is capable of making large advances towards both of these objectives and describe a modest network of telescopes that is able to make the requisite observations. In a system where a known planet transits its host star, a second planet in that system will cause the time between transits to vary. These transit timing variations can be used to infer the orbital elements and mass of the perturbing planet even if it has a mass that is smaller than the mass of the Earth. This detection technique complements other techniques because it is most sensitive in mean-motion resonances where, due to degeneracies, other techniques have reduced sensitivity. Small ground-based observatories have already exceeded the photometric precision necessary to detect sub-Ea...

  6. Predictable patterns in planetary transit timing variations and transit duration variations due to exomoons

    CERN Document Server

    Heller, René; Placek, Ben; Angerhausen, Daniel; Agol, Eric

    2016-01-01

    We present new ways to identify single and multiple moons around extrasolar planets using planetary transit timing variations (TTVs) and transit duration variations (TDVs). For planets with one moon, measurements from successive transits exhibit a hitherto undescribed pattern in the TTV-TDV diagram, originating from the stroboscopic sampling of the planet's orbit around the planet-moon barycenter. This pattern is fully determined and analytically predictable after three consecutive transits. The more measurements become available, the more the TTV-TDV diagram approaches an ellipse. For planets with multiple moons in orbital mean motion resonance (MMR), like the Galilean moons, the pattern is much more complex and addressed numerically in this report. Exomoons in MMR can also form closed, predictable TTV-TDV figures if the drift of the moons' pericenters is sufficiently slow. We find that MMR exomoons produce loops in the TTV-TDV diagram and that the number of these loops is equal to the order of the MMR, or t...

  7. A flexible coefficient smooth transition time series model.

    Science.gov (United States)

    Medeiros, Marcelo C; Veiga, Alvaro

    2005-01-01

    In this paper, we consider a flexible smooth transition autoregressive (STAR) model with multiple regimes and multiple transition variables. This formulation can be interpreted as a time varying linear model where the coefficients are the outputs of a single hidden layer feedforward neural network. This proposal has the major advantage of nesting several nonlinear models, such as, the self-exciting threshold autoregressive (SETAR), the autoregressive neural network (AR-NN), and the logistic STAR models. Furthermore, if the neural network is interpreted as a nonparametric universal approximation to any Borel measurable function, our formulation is directly comparable to the functional coefficient autoregressive (FAR) and the single-index coefficient regression models. A model building procedure is developed based on statistical inference arguments. A Monte Carlo experiment showed that the procedure works in small samples, and its performance improves, as it should, in medium size samples. Several real examples are also addressed.

  8. Optimizing the search for transiting planets in long time series

    Science.gov (United States)

    Ofir, Aviv

    2014-01-01

    Context. Transit surveys, both ground- and space-based, have already accumulated a large number of light curves that span several years. Aims: The search for transiting planets in these long time series is computationally intensive. We wish to optimize the search for both detection and computational efficiencies. Methods: We assume that the searched systems can be described well by Keplerian orbits. We then propagate the effects of different system parameters to the detection parameters. Results: We show that the frequency information content of the light curve is primarily determined by the duty cycle of the transit signal, and thus the optimal frequency sampling is found to be cubic and not linear. Further optimization is achieved by considering duty-cycle dependent binning of the phased light curve. By using the (standard) BLS, one is either fairly insensitive to long-period planets or less sensitive to short-period planets and computationally slower by a significant factor of ~330 (for a 3 yr long dataset). We also show how the physical system parameters, such as the host star's size and mass, directly affect transit detection. This understanding can then be used to optimize the search for every star individually. Conclusions: By considering Keplerian dynamics explicitly rather than implicitly one can optimally search the BLS parameter space. The presented Optimal BLS enhances the detectability of both very short and very long period planets, while allowing such searches to be done with much reduced resources and time. The Matlab/Octave source code for Optimal BLS is made available. The MATLAB code is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A138

  9. Predictable patterns in planetary transit timing variations and transit duration variations due to exomoons

    Science.gov (United States)

    Heller, René; Hippke, Michael; Placek, Ben; Angerhausen, Daniel; Agol, Eric

    2016-06-01

    We present new ways to identify single and multiple moons around extrasolar planets using planetary transit timing variations (TTVs) and transit duration variations (TDVs). For planets with one moon, measurements from successive transits exhibit a hitherto undescribed pattern in the TTV-TDV diagram, originating from the stroboscopic sampling of the planet's orbit around the planet-moon barycenter. This pattern is fully determined and analytically predictable after three consecutive transits. The more measurements become available, the more the TTV-TDV diagram approaches an ellipse. For planets with multiple moons in orbital mean motion resonance (MMR), like the Galilean moon system, the pattern is much more complex and addressed numerically in this report. Exomoons in MMR can also form closed, predictable TTV-TDV figures, as long as the drift of the moons' pericenters is sufficiently slow. We find that MMR exomoons produce loops in the TTV-TDV diagram and that the number of these loops is equal to the order of the MMR, or the largest integer in the MMR ratio. We use a Bayesian model and Monte Carlo simulations to test the discoverability of exomoons using TTV-TDV diagrams with current and near-future technology. In a blind test, two of us (BP, DA) successfully retrieved a large moon from simulated TTV-TDV by co-authors MH and RH, which resembled data from a known Kepler planet candidate. Single exomoons with a 10% moon-to-planet mass ratio, like to Pluto-Charon binary, can be detectable in the archival data of the Kepler primary mission. Multi-exomoon systems, however, require either larger telescopes or brighter target stars. Complementary detection methods invoking a moon's own photometric transit or its orbital sampling effect can be used for validation or falsification. A combination of TESS, CHEOPS, and PLATO data would offer a compelling opportunity for an exomoon discovery around a bright star.

  10. Modelling systematics of ground-based transit photometry I. Implications on transit timing variations

    CERN Document Server

    von Essen, C; Mallonn, M; Tingley, B; Marcussen, M

    2016-01-01

    The transit timing variation technique (TTV) has been widely used to detect and characterize multiple planetary systems. Due to the observational biases imposed mainly by the photometric conditions and instrumentation and the high signal-to-noise required to produce primary transit observations, ground-based data acquired using small telescopes limit the technique to the follow-up of hot Jupiters. However, space-based missions such as Kepler and CoRoT have already revealed that hot Jupiters are mainly found in single systems. Thus, it is natural to question ourselves if we are properly using the observing time at hand carrying out such follow-ups, or if the use of medium-to-low quality transit light curves, combined with current standard techniques of data analysis, could be playing a main role against exoplanetary search via TTVs. The purpose of this work is to investigate to what extent ground-based observations treated with current modelling techniques are reliable to detect and characterize additional pla...

  11. Embedding and Distributing Constant Time Delay in Circle Time and Transitions.

    Science.gov (United States)

    Wolery, Mark; Anthony, Leslie; Caldwell, Nicola K.; Snyder, Erin D.; Morgante, James D.

    2002-01-01

    This study evaluated embedding and distributing constant time delay instructional trials into circle time and transitions between activities in a summer camp program. Three boys (ages 5-8) with disabilities or behavior problems participated. Results indicated the children acquired the behaviors they were taught and generalized the learned…

  12. Time-course microarray analysis for identifying candidate genes involved in obesity-associated pathological changes in the mouse colon.

    Science.gov (United States)

    Bae, Yun Jung; Kim, Sung-Eun; Hong, Seong Yeon; Park, Taesun; Lee, Sang Gyu; Choi, Myung-Sook; Sung, Mi-Kyung

    2016-01-01

    Obesity is known to increase the risk of colorectal cancer. However, mechanisms underlying the pathogenesis of obesity-induced colorectal cancer are not completely understood. The purposes of this study were to identify differentially expressed genes in the colon of mice with diet-induced obesity and to select candidate genes as early markers of obesity-associated abnormal cell growth in the colon. C57BL/6N mice were fed normal diet (11% fat energy) or high-fat diet (40% fat energy) and were euthanized at different time points. Genome-wide expression profiles of the colon were determined at 2, 4, 8, and 12 weeks. Cluster analysis was performed using expression data of genes showing log2 fold change of ≥1 or ≤-1 (twofold change), based on time-dependent expression patterns, followed by virtual network analysis. High-fat diet-fed mice showed significant increase in body weight and total visceral fat weight over 12 weeks. Time-course microarray analysis showed that 50, 47, 36, and 411 genes were differentially expressed at 2, 4, 8, and 12 weeks, respectively. Ten cluster profiles representing distinguishable patterns of genes differentially expressed over time were determined. Cluster 4, which consisted of genes showing the most significant alterations in expression in response to high-fat diet over 12 weeks, included Apoa4 (apolipoprotein A-IV), Ppap2b (phosphatidic acid phosphatase type 2B), Cel (carboxyl ester lipase), and Clps (colipase, pancreatic), which interacted strongly with surrounding genes associated with colorectal cancer or obesity. Our data indicate that Apoa4, Ppap2b, Cel, and Clps are candidate early marker genes associated with obesity-related pathological changes in the colon. Genome-wide analyses performed in the present study provide new insights on selecting novel genes that may be associated with the development of diseases of the colon.

  13. Optimizing the search for transiting planets in long time series

    CERN Document Server

    Ofir, Aviv

    2013-01-01

    Context: Transit surveys, both ground- and space- based, have already accumulated a large number of light curves that span several years. Aims: The search for transiting planets in these long time series is computationally intensive. We wish to optimize the search for both detection and computational efficiencies. Methods: We assume that the searched systems can be well described by Keplerian orbits. We then propagate the effects of different system parameters to the detection parameters. Results: We show that the frequency information content of the light curve is primarily determined by the duty cycle of the transit signal, and thus the optimal frequency sampling is found to be cubic and not linear. Further optimization is achieved by considering duty-cycle dependent binning of the phased light curve. By using the (standard) BLS one is either rather insensitive to long-period planets, or less sensitive to short-period planets and computationally slower by a significant factor of ~330 (for a 3yr long dataset...

  14. Numerical and Analytical Modeling of Transit Timing Variations

    Science.gov (United States)

    Hadden, Sam; Lithwick, Yoram

    2016-09-01

    We develop and apply methods to extract planet masses and eccentricities from observed transit timing variations (TTVs). First, we derive simple analytic expressions for the TTV that include the effects of both first- and second-order resonances. Second, we use N-body Markov chain Monte Carlo simulations, as well as the analytic formulae, to measure the masses and eccentricities of 10 planets discovered by Kepler that have not previously been analyzed. Most of the 10 planets have low densities. Using the analytic expressions to partially circumvent degeneracies, we measure small eccentricities of a few percent or less.

  15. Numerical and Analytical Modelling of Transit Time Variations

    CERN Document Server

    Hadden, Sam

    2015-01-01

    We develop and apply methods to extract planet masses and eccentricities from observed transit time variations (TTVs). First, we derive simple analytic expressions for the TTV that include the effects of both first- and second-order resonances. Second, we use N-body Markov chain Monte Carlo (MCMC) simulations, as well as the analytic formulae, to measure the masses and eccentricities of ten planets discovered by Kepler that have not previously been analyzed. Most of the ten planets have low densities. Using the analytic expressions to partially circumvent degeneracies, we measure small eccentricities of a few percent or less.

  16. Real-Time History of the Cosmological Electroweak Phase Transition

    CERN Document Server

    Kurki-Suonio, H

    1996-01-01

    We study numerically the real-time history of the cosmological electrow= eak phase transition, as it may take place in the Standard Model or in MSSM f= or m_H < m_W according to recent lattice results. We follow the nucleated bubble= s from the initial stages of acceleration and rapid growth, through collisions w= ith compression waves resulting in slowing down and reheating to T_c, until t= he final stages of slow growth and evaporation. We find that collisions with compression waves may make the bubble walls oscillate in the radial direc= tion, and that reheating to T_c takes generically place.

  17. [Evaluation of oro-cecal transit time in patients with irritable bowel syndrome with cereal products intolerance].

    Science.gov (United States)

    Błońska, Aleksandra; Konrad, Paulina; Chojnacki, Jan; Chojnacki, Cezary

    2017-03-21

    The main symptoms of irritable bowel syndrome (IBS) include abnormal frequency of bowel movements. On this basis, three main clinical types of the disease have been distinguished, i.e.: constipation (IBSC), diarrhea (IBS-D) and mixed-type (IBS-M) in accordance with the Rome III criteria. These disorders mainly affect the colon, but symptoms related to upper gastrointestinal tract are also often observed. The aim of the study was to assess the oro-caecal transit time in patients with irritable bowel syndrome with IgG-dependent hypersensitivity to cereal products. The study was performed in three 30-person groups, aged 27-48 years (38.3 ± 10.4), in whom three types of IBS were diagnosed basing on the Rome III criteria . The control group consisted of 30 subjects without gastrointestinal symptoms. Orocaecal transit time was measured by hydrogen breath test using lactulose and Gastro + Gastrolyzer (Bedfont). The mean oro-caecal transit time was respectively in the groups: controls - 86,3 ± 5,95 min., IBS-C - 95,8 ±10,9 min. (p0,05). There was a positive correlation between the transit time and disorder severity in IBS-C (p=0,05) group and negative in IBS-D (pirritable bowel syndrome.

  18. Host Physiologic Changes Induced by Influenza A Virus Lead to Staphylococcus aureus Biofilm Dispersion and Transition from Asymptomatic Colonization to Invasive Disease

    Directory of Open Access Journals (Sweden)

    Ryan M. Reddinger

    2016-08-01

    Full Text Available Staphylococcus aureus is a ubiquitous opportunistic human pathogen and a major health concern worldwide, causing a wide variety of diseases from mild skin infections to systemic disease. S. aureus is a major source of severe secondary bacterial pneumonia after influenza A virus infection, which causes widespread morbidity and mortality. While the phenomenon of secondary bacterial pneumonia is well established, the mechanisms behind the transition from asymptomatic colonization to invasive staphylococcal disease following viral infection remains unknown. In this report, we have shown that S. aureus biofilms, grown on an upper respiratory epithelial substratum, disperse in response to host physiologic changes related to viral infection, such as febrile range temperatures, exogenous ATP, norepinephrine, and increased glucose. Mice that were colonized with S. aureus and subsequently exposed to these physiologic stimuli or influenza A virus coinfection developed pronounced pneumonia. This study provides novel insight into the transition from colonization to invasive disease, providing a better understanding of the events involved in the pathogenesis of secondary staphylococcal pneumonia.

  19. Daylight saving time transitions and acute myocardial infarction.

    Science.gov (United States)

    Čulić, Viktor

    2013-06-01

    Most recently, the possible impact of transitions to and from daylight saving time (DST) on the increased incidence of acute myocardial infarction (AMI) has been suggested. The goal of this report was to analyze independent influence of DST transitions on the incidence of AMI with simultaneous control for the confounding presence of situational triggers such as physical exertion, emotional stress, heavy meals, and sexual intercourse, as well as for other clinical factors. Detailed information was obtained from 2412 patients and included baseline characteristics, working status, exact time of AMI, possible external triggers, cardiovascular risk factors, and prehospital medication. AMI incidence on days after the DST was compared with incidence during control periods and patient characteristics, cardiovascular medication, and circumstances of AMI were evaluated to identify potential risk modifiers. Relative risks of AMI and differences in patient characteristics were expressed through incidence ratios and odds ratios, respectively, with 95% confidence intervals (CIs). Multivariate analysis was performed by using a stepwise multiple regression to assess the independent predictive significance of the characteristics of patients for the AMI occurring in the posttransitional period. The incidence ratio for AMI for the first four workdays after the spring DST transition was 1.29 (95% CI: 1.09-1.49) and the excess was particularly prominent on Monday. In autumn, the incidence ratio for AMI for this 4-d period was 1.44 (95% CI: 1.19-1.69), with peaks on Tuesday and Thursday. The independent predictors for AMI during this period in spring were male sex (p = 0.03) and nonengagement in physical activity (p = 0.02) and there was a trend for the lower risk of incident among those taking calcium antagonists (p = 0.07). In autumn, the predictors were female sex (p = 0.04), current employment (p = 0.006), not taking β-blocker (p = 0.03), and nonengagement in physical activity (p

  20. RSRM Chamber Pressure Oscillations: Transit Time Models and Unsteady CFD

    Science.gov (United States)

    Nesman, Tom; Stewart, Eric

    1996-01-01

    Space Shuttle solid rocket motor low frequency internal pressure oscillations have been observed since early testing. The same type of oscillations also are present in the redesigned solid rocket motor (RSRM). The oscillations, which occur during RSRM burn, are predominantly at the first three motor cavity longitudinal acoustic mode frequencies. Broadband flow and combustion noise provide the energy to excite these modes at low levels throughout motor burn, however, at certain times during burn the fluctuating pressure amplitude increases significantly. The increased fluctuations at these times suggests an additional excitation mechanism. The RSRM has inhibitors on the propellant forward facing surface of each motor segment. The inhibitors are in a slot at the segment field joints to prevent burning at that surface. The aft facing segment surface at a field joint slot burns and forms a cavity of time varying size. Initially the inhibitor is recessed in the field joint cavity. As propellant burns away the inhibitor begins to protrude into the bore flow. Two mechanisms (transit time models) that are considered potential pressure oscillation excitations are cavity-edge tones, and inhibitor hole-tones. Estimates of frequency variation with time of longitudinal acoustic modes, cavity edge-tones, and hole-tones compare favorably with frequencies measured during motor hot firing. It is believed that the highest oscillation amplitudes occur when vortex shedding frequencies coincide with motor longitudinal acoustic modes. A time accurate computational fluid dynamic (CFD) analysis was made to replicate the observations from motor firings and to observe the transit time mechanisms in detail. FDNS is the flow solver used to detail the time varying aspects of the flow. The fluid is approximated as a single-phase ideal gas. The CFD model was an axisymmetric representation of the RSRM at 80 seconds into burn.Deformation of the inhibitors by the internal flow was determined

  1. The helpfulness and timing of transition program education.

    Science.gov (United States)

    Rush, Kathy L; Adamack, Monica; Janke, Robert; Gordon, Jason; Ghement, Isabella R

    2013-01-01

    The purpose of this study was to examine relationships between transition program education and new graduate nurse transition. Although new graduates preferred hands-on learning, the helpfulness of workshops was associated with better transition. New graduates, many of whom were from the Millennial Generation, liked a variety of educational modalities. Access to support was better for nurse graduates who received education delivered throughout the first year of transition.

  2. Quantum to classical transition induced by gravitational time dilation

    Science.gov (United States)

    Sokolov, Boris; Vilja, Iiro; Maniscalco, Sabrina

    2017-07-01

    We study the loss of quantumness caused by time dilation [I. Pikovski, M. Zych, F. Costa, and Č. Brukner, Nat. Phys. 11, 668 (2015), 10.1038/nphys3366] for a Schrödinger cat state. We give a holistic view of the quantum to classical transition by comparing the dynamics of several nonclassicality indicators, such as the Wigner function interference fringe, the negativity of the Wigner function, the nonclassical depth, the Vogel criterion, and the Klyshko criterion. Our results show that only two of these indicators depend critically on the size of the cat, namely, on how macroscopic the superposition is. Finally we compare the gravitation-induced decoherence times to the typical decoherence times due to classical noise originating from the unavoidable statistical fluctuations in the characteristic parameters of the system [J. Trapani, M. Bina, S. Maniscalco, and M. G. A. Paris, Phys. Rev. A 91, 022113 (2015), 10.1103/PhysRevA.91.022113]. We show that the experimental observation of decoherence due to time dilation imposes severe limitations on the allowed levels of classical noise in the experiments.

  3. Toward a Smartphone Application for Estimation of Pulse Transit Time

    Directory of Open Access Journals (Sweden)

    He Liu

    2015-10-01

    Full Text Available Pulse transit time (PTT is an important physiological parameter that directly correlates with the elasticity and compliance of vascular walls and variations in blood pressure. This paper presents a PTT estimation method based on photoplethysmographic imaging (PPGi. The method utilizes two opposing cameras for simultaneous acquisition of PPGi waveform signals from the index fingertip and the forehead temple. An algorithm for the detection of maxima and minima in PPGi signals was developed, which includes technology for interpolation of the real positions of these points. We compared our PTT measurements with those obtained from the current methodological standards. Statistical results indicate that the PTT measured by our proposed method exhibits a good correlation with the established method. The proposed method is especially suitable for implementation in dual-camera-smartphones, which could facilitate PTT measurement among populations affected by cardiac complications.

  4. Factors influencing stream baseflow transit times in tropical montane watersheds

    Science.gov (United States)

    Muñoz-Villers, Lyssette E.; Geissert, Daniel R.; Holwerda, Friso; McDonnell, Jeffrey J.

    2016-04-01

    Stream water mean transit time (MTT) is a fundamental hydrologic parameter that integrates the distribution of sources, flow paths, and storages present in catchments. However, in the tropics little MTT work has been carried out, despite its usefulness for providing important information on watershed functioning at different spatial scales in (largely) ungauged basins. In particular, very few studies have quantified stream MTTs or have related these to catchment characteristics in tropical montane regions. Here we examined topographic, land use/cover and soil hydraulic controls on baseflow transit times for nested catchments (0.1-34 km2) within a humid mountainous region, underlain by volcanic soil (Andisols) in central Veracruz (eastern Mexico). We used a 2-year record of bi-weekly isotopic composition of precipitation and stream baseflow data to estimate MTT. Land use/cover and topographic parameters (catchment area and form, drainage density, slope gradient and length) were derived from geographic information system (GIS) analysis. Soil water retention characteristics, and depth and permeability of the soil-bedrock interface were obtained from intensive field measurements and laboratory analysis. Results showed that baseflow MTTs ranged between 1.2 and 2.7 years across the 12 study catchments. Overall, MTTs across scales were mainly controlled by catchment slope and the permeability observed at the soil-bedrock interface. In association with topography, catchment form and the depth to the soil-bedrock interface were also identified as important features influencing baseflow MTTs. The greatest differences in MTTs were found both within groups of small (0.1-1.5 km2) and large (14-34 km2) catchments. Interestingly, the longest stream MTTs were found in the headwater cloud forest catchments.

  5. Preparation and evaluation of electrospun nanofibers containing pectin and time-dependent polymers aimed for colonic drug delivery of celecoxib

    Directory of Open Access Journals (Sweden)

    A. Akhgari

    2016-01-01

    Full Text Available Objective(s:The aim of this study was to prepare electrospun nanofibers of celecoxib using combination of time-dependent polymers with pectin to achieve a colon-specific drug delivery system for celecoxib. Materials and Methods:Formulations were produced based on two multilevel 22 full factorial designs. The independent variables were the ratio of drug:time-dependent polymer (X1 and the amount of pec­tin in formulations (X2. Electrospinning process was used for preparation of nanofibers. The spinning solutions were loaded in 5 mL syringes. The feeding rate was fixed by a syringe pump at 2.0 mL/h and a high voltage supply at range 10-18 kV was applied for electrospinning. Electrospun nanofibers were collected and evaluated by scanning electron microscopy and drug release in the acid and buffer with pH 6.8 with and without pectinase. Results:Electrospun nanofibers of celecoxib with appropriate morphological properties were produced via electrospinning process. Drug release from electrospun nanofibers was very low in the acidic media; while, drug release in the simulated colonic media was the highest from formulations containing pectin. Conclusion: Formulation F2 (containing drug:ERS with the ratio of 1:2 and 10% pectin exhibited acceptable morphological characteristics and protection of drug in the upper GI tract and could be a good candidate as a colonic drug delivery system for celecoxib.

  6. Time-restricted flight ability influences dispersal and colonization rates in a group of freshwater beetles.

    Science.gov (United States)

    Iversen, Lars Lønsmann; Rannap, Riinu; Briggs, Lars; Sand-Jensen, Kaj

    2017-02-01

    Variation in the ability to fly or not is a key mechanism for differences in local species occurrences. It is increasingly acknowledged that physiological or behavioral mechanisms rather than morphological differences may drive flight abilities. However, our knowledge on the seasonal variability and stressors creating nonmorphological differences in flight abilities and how it scales to local and regional occurrences is very limited particularly for small, short-lived species such as insects. Here, we examine how flight ability might vary across seasons and between two closely related genera of freshwater beetles with similar geographical ranges, life histories, and dispersal-related morphology. By combining flight experiments of >1,100 specimens with colonization rates in a metacommunity of 54 ponds in northern and eastern Europe, we have analyzed the relationship between flight ability and spatio-environmental distribution of the study genera. We find profound differences in flight ability between the two study genera across seasons. High flight ability for Acilius (97% of the tested individuals flew during the experiments) and low for Graphoderus (14%) corresponded to the different colonization rates of newly created ponds. Within a 5-year period, 81 and 31% of the study ponds were colonized by Acilius and Graphoderus, respectively. While Acilius dispersed throughout the season, flight activity in Graphoderus was restricted to stressed situations immediately after the emergence of adults. Regional colonization ability of Acilius was independent of spatial connectivity and mass effect from propagule sources. In contrast, Graphoderus species were closely related to high connectivity between ponds in the landscape. Our data suggest that different dispersal potential can account for different local occurrences of Acilius and Graphoderus. In general, our findings provide some of the first insights into the understanding of seasonal restrictions in flight patterns of

  7. Effect of soil-spraying time on root-colonization ability of antagonistic Streptomyces griseoviridis

    Directory of Open Access Journals (Sweden)

    H. KORTEMAA

    2008-12-01

    Full Text Available The root-colonization ability of Streptomyces griseoviridis Anderson et al. was tested on turnip rape (Brassica rapa subsp. oleifera DC. and carrot (Daucus carota L. by the sand-tube method. Non-sterile sand was sprayed with a microbial suspension immediately or 7 days after the seed had been sown. Results expressed as population frequencies and densities indicated that S. griseoviridis effectively colonizes the rhizosphere when the microbe is applied immediately after sowing but less effectively when it is applied 7 days later. Detection values of S. griseoviridis were higher for turnip rape than for carrot. In sterile sand, S. griseoviridis invaribly colonized the rhizosphere of turnip rape after each of the two applications. These findings indicate that S. griseoviridis can compete with indigenous soil microbes in the rhizosphere if it is sufficiently abundant in the soil before the seed emerges. If applied later, however, it competes rather poorly. In root-free nonsterile sand, S. griseoviridis dispersed and survived well.;

  8. Time Irreversibility from Time Series for Analyzing Oil-in-Water Flow Transition

    Directory of Open Access Journals (Sweden)

    Du Meng

    2016-01-01

    Full Text Available We first experimentally collect conductance fluctuation signals of oil-in-water two-phase flow in a vertical pipe. Then we detect the flow pattern asymmetry character from the collected signals with multidimensional time irreversibility and multiscale time irreversibility index. Moreover, we propose a novel criterion, that is, AMSI (average of multiscale time irreversibility, to quantitatively investigate the oil-in-water two-phase flow pattern dynamics. The results show that AMSI is sensitive to the flow pattern evolution that can be used to predict the flow pattern transition and bubble coalescence.

  9. Transition Between the Timed up and Go Turn to Sit Subtasks: Is Timing Everything?

    Science.gov (United States)

    Weiss, Aner; Mirelman, Anat; Giladi, Nir; Barnes, Lisa L; Bennett, David A; Buchman, Aron S; Hausdorff, Jeffrey M

    2016-09-01

    The Timed Up and Go (TUG), one of the most widely used tests of mobility, has been validated and associated with adverse outcomes in the community, acute care, and nursing home setting. It is composed of several distinct subtasks; however, the temporal relationship when transitioning between subtasks has not been well-studied. We tested the hypothesis that longer transition durations between the final turn to the sitting subtasks are associated with worse motor and cognitive performance in older adults. A total of 1055 participants (80.33 ± 7.57 years, 76.96% female) performed the TUG while wearing a 3-dimensional inertial sensor on their lower back. We employed a series of linear regressions to examine the association of the duration between the turn and sitting subtasks with clinical characteristics including motor and cognitive functions. Participants employed 2 different strategies when they transitioned from turning to sitting. (1) Distinct transition strategy: 816 participants (77.34%) first completed the turn before starting to sit. The average duration between these distinct subtasks (D-interval) was 715 ± 980 ms. (2) Overlapping transition strategy: 239 participants (22.65%) started to sit before completing the turn. The average overlap duration between these tasks (O-interval) was 237 ± 269 ms. Participants who employed the distinct transition strategy were slightly younger than those who employed the overlapping transition strategy (P ≤ .013). Higher D-intervals and O-intervals were associated with worse TUG performance (P ≤ .02), with poorer motor and cognitive function, [ie, worse parkinsonian gait (P ≤ .001), lower level of perceptual speed (P ≤ .03), and with worse mobility disability (P ≤ .001)]. A longer D-interval was associated with worse gait speed and bradykinesia (P ≤ .001), whereas a longer O-interval was associated with increased rigidity (P = .004). Older adults apparently employ 2 different strategies

  10. Deconfinement Phase Transition in an Expanding Quark system in Relaxation Time Approximation

    CERN Document Server

    Yang, Z; Yang, Zhenwei; Zhuang, Pengfei

    2004-01-01

    We investigated the effects of nonequilibrium and collision terms on the deconfinement phase transition of an expanding quark system in Friedberg-Lee model in relaxation time approximation. By calculating the effective quark potential, the critical temperature of the phase transition is dominated by the mean field, while the collisions among quarks and mesons change the time structure of the phase transition significantly.

  11. Conductivity and transit time estimates of a soil liner

    Science.gov (United States)

    Krapac, I.G.; Cartwright, K.; Panno, S.V.; Hensel, B.R.; Rehfeldt, K.H.; Herzog, B.L.

    1990-01-01

    A field-scale soil linear was built to assess the feasibilty of constructing a liner to meet the saturated hydraulic conductivity requirement of the U.S. EPA (i.e., less than 1 ?? 10-7 cm/s), and to determine the breakthrough and transit times of water and tracers through the liner. The liner, 8 ?? 15 ?? 0.9 m, was constructed in 15-cm compacted lifts using a 20,037-kg pad-foot compactor and standard engineering practices. Estimated saturated hydraulic conductivities were 2.4 ?? 10-9 cm/s, based on data from large-ring infiltrometers; 4.0 ?? 10-8 cm/s from small-ring infiltrometers; and 5.0 ?? 10-8 cm/s from a water-balance analysis. These estimates were derived from 1 year of monitoring water infiltration into the linear. Breakthrough of tracers at the base of the liner was estimated to be between 2 and 13 years, depending on the method of calculation and the assumptions used in the calculation.

  12. Scintigraphic determination of small intestinal transit time of water in man

    Energy Technology Data Exchange (ETDEWEB)

    Prokop, E.K.; Caride, V.J.; Marano, A.R.; McCallum, R.

    1984-01-01

    A method utilizing a lactulose solution to measure small intestinal transit time (SITT) has been previously reported. Lactulose is a non-absorbable sugar and is known to increase SITT. In order to determine the extent to which lactulose accelerates SITT, a group of 4 normal male volunteers were studied after the ingestion of 150cc of water to which 100 uCi of 111-In was added. To provide adequate caloric intake, as occurs physiologically, the water was drunk while ingesting a solid meal. The subject was then placed supine under a 15 inch gamma camera. Data were collected and stored in a computer at one frame every 3 minute for 240 minutes. If activity was not present in the cecal region by this time, the subject was allowed to move about for 15 minutes and then repositioned under the gamma camera. Data were first viewed in a movie format. Regions of interest were selected over the cecum and ascending colon. The time of first appearance of radioactivity in the region of the cecum was taken as the SITT. Each subject was studied on three separate occasions. The mean (+- SEM) SITT for each of the separate studies was 248 +- 58 min., 240 +- 47 min. and 232 +- 54 min. respectively (pless than or equal toNS). Two previously studied groups of normal volunteers had a mean SITT of approximately 80 minutes. Water appears to have a significantly slower SITT when ingested with a solid meal when compared to lactulose. Clinically, the potential to use water as a test for SITT would not seem to be as attractive or practical as using lactulose as the test substance.

  13. Modeling hyporheic exchange and in-stream transport with time-varying transit time distributions

    Science.gov (United States)

    Ball, A.; Harman, C. J.; Ward, A. S.

    2014-12-01

    Transit time distributions (TTD) are used to understand in-stream transport and exchange with the hyporheic zone by quantifying the probability of water (and of dissolved material) taking time T to traverse the stream reach control volume. However, many studies using this method assume a TTD that is time-invariant, despite the time-variability of the streamflow. Others assume that storage is 'randomly sampled' or 'well-mixed' with a fixed volume or fixed exchange rate. Here we present a formulation for a time-variable TTD that relaxes both the time-invariant and 'randomly sampled' assumptions and only requires a few parameters. The framework is applied to transient storage, representing some combination of in-stream and hyporheic storage, along a stream reach. This approach does not assume that hyporheic and dead-zone storage is fixed or temporally-invariant, and allows for these stores to be sampled in more physically representative ways determined by the system itself. Instead of using probability distributions of age, probability distributions of storage (ranked by age) called Ω functions are used to describe how the off-stream storage is sampled in the outflow. Here the Ω function approach is used to describe hyporheic exchange during diurnal fluctuations in streamflow in a gaining reach of the H.J. Andrews Experimental Forest. The breakthrough curves of salt slugs injected four hours apart over a 28-hour period show a systematic variation in transit time distribution. This new approach allows us to relate these salt slug TTDs to a corresponding time-variation in the Ω function, which can then be related to changes in in-stream storage and hyporheic zone mobilization under varying flow conditions. Thus, we can gain insights into how channel storage and hyporheic exchange are changing through time without having to specify difficult to measure or unmeasurable quantities of our system, such as total storage.

  14. CCR6 expression in colon cancer is associated with advanced disease and supports epithelial-to-mesenchymal transition.

    Science.gov (United States)

    Kapur, Neeraj; Mir, Hina; Clark Iii, Clarence E; Krishnamurti, Uma; Beech, Derrick J; Lillard, James W; Singh, Shailesh

    2016-06-14

    Adjuvant chemotherapy offered to treat colon cancer is based on the TNM staging system, which often fails due to molecular heterogeneity and undefined molecular mechanisms independent of TNM. Therefore, identification of markers to better predict therapeutic option and outcome is needed. In this study we have characterised the clinical association of CCR6 with colon cancer and defined CCR6-mediated molecular pathway. Immunohistochemistry, RT-qPCR, western blot and FACS were used to determine expression of CCR6 and/or EMT markers in colon tissues/cells. BrdU assay and trans-well system were used to determine cell proliferation, migration and invasion in response to CCL20. CCR6 was higher in cancer cases compared to normal adjacent tissue and expression was associated with nodal status and distant metastasis. Similarly, CCR6 expression was higher in cells derived from node-positive cases and highest expression was in cells derived from metastatic cases. Significant changes in EMT markers, that is, E-cadherin, vimentin, β-catenin, N-cadherin, α-SMA, SNAILl and ZEB1 were observed in response to CCL20 along with decreased proliferation, increased migratory and invasive potential. Results suggest CCR6 as a potential therapeutic target as well as biomarker in addition to nodal status for predicting therapeutic option.

  15. Radiographic anatomy and barium sulfate contrast transit time of the gastrointestinal tract of bearded dragons (Pogona vitticeps).

    Science.gov (United States)

    Grosset, Claire; Daniaux, Lise; Guzman, David Sanchez-Migallon; Weber, Ernest Scott; Zwingenberger, Allison; Paul-Murphy, Joanne

    2014-01-01

    The positive contrast gastrointestinal study is a common non-invasive diagnostic technique that does not require anesthesia and enables good visualization of the digestive tract. Radiographic anatomy and reference intervals for gastrointestinal contrast transit time in inland bearded dragons (Pogona vitticeps) were established using seven animals administered 15 ml/kg of a 35% w/v suspension of barium by esophageal gavage. Dorso-ventral and lateral radiographic views were performed at 0, 15, 30 min, 1, 2, 4, 6, 8, 12 h, and then every 12 h up to 96 h after barium administration. Gastric emptying was complete at a median time of 10 h (range 4-24 h). Median jejunum and small intestinal emptying times were 1 h (range 30 min-2 h) and 29 h (range 24-48 h), respectively. Median transit time for cecum was 10 h (range 8-12 h). Median time for contrast to reach the colon was 31 h (range 12-72 h) after administration. Results were compared to those obtained in other reptilian species. This technique appeared safe in fasted bearded dragons and would be clinically applicable in other lizard species.

  16. TTVFast: An efficient and accurate code for transit timing inversion problems

    CERN Document Server

    Deck, Katherine M; Holman, Matthew J; Nesvorny, David

    2014-01-01

    Transit timing variations (TTVs) have proven to be a powerful technique for confirming Kepler planet candidates, for detecting non-transiting planets, and for constraining the masses and orbital elements of multi-planet systems. These TTV applications often require the numerical integration of orbits for computation of transit times (as well as impact parameters and durations); frequently tens of millions to billions of simulations are required when running statistical analyses of the planetary system properties. We have created a fast code for transit timing computation, TTVFast, which uses a symplectic integrator with a Keplerian interpolator for the calculation of transit times (Nesvorny et al. 2013). The speed comes at the expense of accuracy in the calculated times, but the accuracy lost is largely unnecessary, as transit times do not need to be calculated to accuracies significantly smaller than the measurement uncertainties on the times. The time step can be tuned to give sufficient precision for any p...

  17. Cisapride decreasing orocecal transit time in patients with nonalcoholic steatohepatitis

    Institute of Scientific and Technical Information of China (English)

    Xiang-Sheng Fu; Feng Jiang

    2006-01-01

    BACKGROUND:Altered small-intestine motility, lengthening of orocecal transit time (OCTT), and small-intestinal bacterial overgrowth (SIBO) have been detected in patients with nonalcoholic steatohepatitis (NASH). These changes might be related to the progressive course and poor prognosis of the disease. This study was undertaken to investigate the effect of 4-week treatment with cisapride on OCTT. METHODS: Ten NASH patients without diabetes were included. Ten healthy individuals served as controls. OCTT was measured by lactulose breath test (LBT). Anti-endotoxin core antibodies (EndoCAb) IgG were also examined. The effect of cisapride (10 mg TID during 4 weeks) on LBT and serum EndoCAb IgG levels in NASH patients was investigated. RESULTS: The NASH patients had more signiifcantly prolonged OCTT (95±17 min) than the controls (59±18 min, P=0.00032). Cisapride administration decreased OCTT (from 95±17 min to 83±19 min, P=0.037), basal breathed H2 (from 9.87±1.60 ppm to 8.61±1.63 ppm, P=0.046) and EndoCAb IgG titers (from 5.24±0.68 GMU/ml to 4.20±0.72 GMU/ml, P=0.013) in NASH patients. CONCLUSIONS:The present data suggest the existence of deranged intestinal motility and endotoxemia in NASH patients. Cisapride administration during 4 weeks possibly restore intestinal motility and ameliorate endotoxemia in NASH patients.

  18. TEE, a simple estimator for the precision of eclipse and transit minimum times

    DEFF Research Database (Denmark)

    Deeg, Hans J.; Tingley, Brandon

    2016-01-01

    Context: Transit or eclipse timing variations have proven to be a valuable tool in exoplanet research. However, no simple way to estimate the potential precision of such timing measures has been presented yet, nor are guidelines available regarding the relation between timing errors and sampling......: The simulations show that the TEE gives timing errors very close to the correct value, as long as the temporal sampling is faster than transit ingress/egress durations and transits with very low S/N are avoided. Conclusions: The TEE is a useful tool to estimate eclipse or transit timing errors in actual...

  19. Biobanking of fresh-frozen human colon tissues: impact of tissue ex-vivo ischemia times and storage periods on RNA quality.

    Science.gov (United States)

    Bao, Wei-Guang; Zhang, Xia; Zhang, Jian-Gang; Zhou, Wen-Jun; Bi, Tie-Nan; Wang, Jiao-Chen; Yan, Wei-Hua; Lin, Aifen

    2013-05-01

    Biobanking plays an important role in translational cancer research. The impact of tissue ex-vivo ischemia time and storage period on RNA integrity is not well documented. Fresh-frozen colon tissues were collected in Taizhou Hospital of Zhejiang Province in China since 2004. Fifty-one colon cancer tissues with tumor cell content higher than 70 % and matched normal tissues during four storage periods (less than 15 months, 16-20 months, 21-25 months, and 26-40 months) were chosen to detect RNA quality. Fresh colon cancer tissues from 5 patients were cut into pieces and kept at room temperature or on ice for 0.5, 1, 2, and 4 h before snap freezing. RNA integrity was determined by microcapillary electrophoresis by the RNA integrity number (RIN) algorithm. Sixty-seven percent of normal colon tissues and 94 % of colon cancer specimens yielded RNA with a RIN of ≥7. Matched colon cancer and normal tissues showed significant difference in RNA quality. RNA remained stable in colon cancer tissues kept at room temperature and on ice for up to 4 h, and long-term storage of banked colon specimens did not negatively influence RNA quality (RNA with RIN of ≥7 banked less than 15 months, 83 %; 16-20 months, 78 %; 21-25 months, 77 %; 26-40 months, 90 %). Frozen colon tissues yield high-quality RNA in approximately 80 % of specimens. Ex-vivo ischemia times and storage periods did not adversely affect RNA quality. This study showed that standard operation protocols and the maintenance of high-quality tissue repositories were the keys to translational medicine research.

  20. Discovering the space-time dimensions of schedule padding and delay from GTFS and real-time transit data

    Science.gov (United States)

    Wessel, Nate; Widener, Michael J.

    2017-01-01

    Schedule padding is the extra time added to transit schedules to reduce the risk of delay. Where there is more random delay, there should be more schedule padding. While schedule padding is a product of transit planners, a method for detecting when and where it exists could provide valuable feedback as transit agencies continually develop their networks. By analyzing transit schedules and real-time vehicle location data at the level of stop-to-stop segments, we can locate padding in space and time and identify the places that may be most effected by stochastic delay. Such information could be used to target delay-reduction interventions such as fare prepayment or transit-only rights of way. The Toronto Transit Commission is used as a case study, and initial results suggest that highly delayed segments appear mostly in the expected, but some surprising, places.

  1. Colon cancer

    Science.gov (United States)

    Colorectal cancer; Cancer - colon; Rectal cancer; Cancer - rectum; Adenocarcinoma - colon; Colon - adenocarcinoma ... In the United States, colorectal cancer is one of the leading causes of deaths due to cancer. Early diagnosis can often lead to a complete cure. Almost ...

  2. Transitive Lie groups on S^1\\times S^{2m}

    Science.gov (United States)

    Gorbatsevich, Vladimir V.

    2007-10-01

    The structure of Lie groups acting transitively on the direct product of a circle and an even-dimensional sphere is described. For products of two spheres of dimension >1 a similar problem has already been solved by other authors. The minimal transitive Lie groups on S^1 and S^{2m} are also indicated. As an application of these results, the structure of the automorphism group of one class of geometric structures, generalized quadrangles (a special case of Tits buildings) is considered. A conjecture put forward by Kramer is proved: the automorphism group of a connected generalized quadrangle of type (1,2m) always contains a transitive subgroup that is the direct product of a compact simple Lie group and a one-dimensional Lie group. Bibliography: 16 titles.

  3. Alteration of interstitial cells of Cajal in the colon of slow transit constipation rats%慢传输型便秘大鼠结肠内Cajal间质细胞的变化

    Institute of Scientific and Technical Information of China (English)

    谭至柔; 谭丽; 黄雪; 秦荔荣

    2011-01-01

    Objective To investigate the alteration of interstitial cells of Cajal (ICC)in the colon of slow transit constipation rats and to detect the role of ICC in the slow transit constipation (STC). Methods Thirty-two healthy Wistar rats were randomly divided into control group and model group of slow transit constipation. The rats in model group received diphenoxylate daily by intragastric administration to develop the slow transit constipated model. 100 days later, intestinal transit functions were examined by activated charcoal pushing test. Meanwhile, the expression of ICC was detected by immunohistochemistry and the alteration was analyzed by the computer image analysis system. Results The movement of contents from the proximal to the distal colon and rectum in model rats was significantly slower than that in normal rats. In model rats, the time of discharge of the first black faeces was 686 ± 57 min, significantly longer than that in normal rats 608 ± 46 min(P < 0.05). ICC in model rats was significantly reduced than that of normal rats. This reduction was more significant in the ICC between the inner and outer layers of the muscularis propria. Conclusion The reduction of ICC in the STC model rats suggests that ICC may play an important role in the pathogenesis of STC.%目的:研究慢传榆型便秘(STC)大鼠结肠内cajal间质细胞(ICC)的变化,探讨ICC在STC发病机制中的作用.方法:用复方苯乙哌啶灌胃法建立STC大鼠模型,免疫组化法检测大鼠结肠ICC,分析大鼠结肠不同部位ICC的变化.结果:STC组大鼠结肠ICC比对照组明显减少.结论:STC大鼠结肠内ICC明显减少,提示ICC在STC的发病机制中可能起重要作用.

  4. Colon targeted curcumin delivery using guar gum.

    Science.gov (United States)

    Elias, Edwin J; Anil, Singhal; Ahmad, Showkat; Daud, Anwar

    2010-06-01

    Curcumin is used in the treatment of colon cancer, but its very poor absorption in the upper part of the GIT is a major concern. As a site for drug delivery, the colon offers a near neutral pH, reduced digestive enzymatic activity, a long transit time and an increased responsiveness to absorption enhancers. The aim of the present study was to identify a suitable polymer (guar gum) based matrix tablet for curcumin with sufficient mechanical strength and promising in vitro mouth-to-colon release profile. Three formulations of curcumin were prepared using varying concentrations of guar gum containing 50 mg curcumin by the wet granulation method. Tablets were subjected to evaluation by studying parameter like hardness, friability, drug content uniformity, and in-vitro drug release. In vitro drug release was evaluated using simulated stomach, intestinal and colonic fluids. The susceptibility of guar gum to colonic bacteria was also assessed by a drug release study with rat caecal contents. The 40% guar gum containing formulation (F-1) showed better drug release (91.1%) after 24 hours in the presence of rat caecal contents in comparison with the 50% guar gum containing formulation (F-2) (82.1%). Curcumin could, thus, be positively delivered to the colon for effective colon cancer treatment using guar gum.

  5. Semileptonic transition of B in noncommutative space- time

    Directory of Open Access Journals (Sweden)

    M Gholami

    2013-09-01

    Full Text Available  In this paper, we study the noncommutative effect on the semileptonic transition of B Ò Dlv . We replace the weak interaction vertex in the ordinary space with its counterpart in the noncommutative space. It is shown that, more new form factors are needded to describe the hadronic part of the transition amplitude. All the form factors are obtained at the lowest order of three point QCD sum rule. Consequently, the decay rate of B Ò Dlv is calculated and a bound of the order of 4 GeV on is given for B Ò Dlv=(5.5 ± 0.5 × 10-2.

  6. Jump time and passage time the duration of a quantum transition

    CERN Document Server

    Schulman, L S

    2001-01-01

    Under unitary evolution, systems move gradually from state to state. An unstable atom has amplitude in its original state after many lifetimes ($\\tau_L$). But in the laboratory, transitions seem to go instantaneously, as suggested by the term "quantum jump." The problem studied here is whether the "jump" can be assigned a duration, in theory and in experiment. Two characteristic times are defined, jump time ($\\tau_J$) and passage time ($\\tau_P$). Both use Zeno time, $\\tau_Z$, defined in terms of $H$ and its initial state as $\\tau_Z \\equiv \\hbar/\\sqrt{}$, with $E_\\psi \\equiv $. $\\tau_J$ is defined in terms of the time needed to slow (\\`a la the quantum Zeno effect) the decay: $\\tau_J \\equiv \\tau_Z^2/\\tau_L$. It appears in several contexts. It is related to tunneling time in barrier penetration. Its inverse is the bandwidth of the Hamiltonian, in a time-energy uncertainty principle. $\\tau_J$ is also an indicator of the duration of the quadratic decay regime in both experiment and in numerical calculations (cf. ...

  7. Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab; Fabrycky, Daniel C.; /Lick Observ.; Ford, Eric B.; /Florida U.; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Lissauer, Jack J.; /NASA, Ames; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Welsh, William F.; /Caltech; Borucki, William J.; /NASA, Ames /UC, Santa Barbara

    2012-01-01

    We present a method to confirm the planetary nature of objects in systems with multiple transiting exoplanet candidates. This method involves a Fourier-domain analysis of the deviations in the transit times from a constant period that result from dynamical interactions within the system. The combination of observed anticorrelations in the transit times and mass constraints from dynamical stability allow us to claim the discovery of four planetary systems, Kepler-25, Kepler-26, Kepler-27 and Kepler-28, containing eight planets and one additional planet candidate.

  8. Transit Timing Observations from Kepler: III. Confirmation of 4 Multiple Planet Systems by a Fourier-Domain Study of Anti-correlated Transit Timing Variations

    CERN Document Server

    Steffen, Jason H; Ford, Eric B; Carter, Joshua A; Desert, Jean-Michel; Fressin, Francois; Holman, Matthew J; Lissauer, Jack J; Moorhead, Althea V; Rowe, Jason F; Ragozzine, Darin; Welsh, William F; Batalha, Natalie M; Borucki, William J; Buchhave, Lars A; Bryson, Steve; Caldwell, Douglas A; Charbonneau, David; Ciardi, David R; Cochran, William D; Endl, Michael; Everett, Mark E; Gautier, Thomas N; Gilliland, Ron L; Girouard, Forrest R; Jenkins, Jon M; Horch, Elliott; Howell, Steve B; Isaacson, Howard; Klaus, Todd C; Koch, David G; Latham, David W; Li, Jie; Lucas, Philip; MacQueen, Phillip J; Marcy, Geoffrey W; McCauliff, Sean; Middour, Christopher K; Morris, Robert L; Mullally, Fergal R; Quinn, Samuel N; Quintana, Elisa V; Shporer, Avi; Still, Martin; Tenenbaum, Peter; Thompson, Susan E; Twicken, Joseph D; Van Cleve, Jeffery

    2012-01-01

    We present a method to confirm the planetary nature of objects in systems with multiple transiting exoplanet candidates. This method involves a Fourier-Domain analysis of the deviations in the transit times from a constant period that result from dynamical interactions within the system. The combination of observed anti-correlations in the transit times and mass constraints from dynamical stability allow us to claim the discovery of four planetary systems Kepler-25, Kepler-26, Kepler-27, and Kepler-28, containing eight planets and one additional planet candidate.

  9. TLR4-mediated galectin-1 production triggers epithelial-mesenchymal transition in colon cancer cells through ADAM10- and ADAM17-associated lactate production.

    Science.gov (United States)

    Park, Ga Bin; Kim, Daejin

    2017-01-01

    Toll-like receptor 4 (TLR4) activation is a key contributor to the carcinogenesis of colon cancer. Overexpression of galectin-1 (Gal-1) also correlates with increased invasive activity of colorectal cancer. Lactate production is a critical predictive factor of risk of metastasis, but the functional relationship between intracellular lactate and Gal-1 expression in TLR4-activated colon cancer remains unknown. In this study, we investigated the underlying mechanism and role of Gal-1 in metastasis and invasion of colorectal cancer (CRC) cells after TLR4 stimulation. Exposure to the TLR4 ligand lipopolysaccharide (LPS) increased expression of Gal-1, induced EMT-related cytokines, triggered the activation of glycolysis-related enzymes, and promoted lactate production. Gene silencing of TLR4 and Gal-1 in CRC cells inhibited lactate-mediated epithelial-mesenchymal transition (EMT) after TLR4 stimulation. Gal-1-mediated activation of a disintegrin and metalloproteinase 10 (ADAM10) and ADAM 17 increased the invasion activity and expression of mesenchymal characteristics in LPS-activated CRC cells. Conversely, inhibition of ADAM10 or ADAM17 effectively blocked the generation of lactate and the migration capacity of LPS-treated CRC cells. Thus, the TLR4/Gal-1 signaling pathway regulates lactate-mediated EMT processes through the activation of ADAM10 and ADAM17 in CRC cells.

  10. Cyclooxygenase-dependent alterations in substance P-mediated contractility and tachykinin NK1 receptor expression in the colonic circular muscle of patients with slow transit constipation.

    Science.gov (United States)

    Liu, Lu; Shang, Fei; Morgan, Matthew J; King, Denis W; Lubowski, David Z; Burcher, Elizabeth

    2009-04-01

    Tachykinins are important neurotransmitters regulating intestinal motility. Slow transit constipation (STC) represents an extreme colonic dysmotility with unknown etiology that predominantly affects women. We examined whether the tachykinin system is involved in the pathogenesis of STC. Isolated sigmoid colon circular muscle from female STC and control patients was studied using functional and quantitative reverse transcriptase-polymerase chain reaction methods. A possible alteration of neurotransmission was investigated by electrical field stimulation (EFS) and ganglionic stimulation by dimethylphenylpiperazinium (DMPP). Substance P (SP)-mediated contractions in circular muscle strips were significantly diminished in STC compared with age-matched control (P DMPP generated biphasic responses, relaxation at lower and contraction at higher concentrations. Although the responses to DMPP were similar in STC and control, an altered contractile pattern in response to EFS was observed in STC circular muscle. In conclusion, we postulate that the diminished contractile response to SP in STC is due to an increased release of inhibitory prostaglandins through activation of up-regulated NK(1) receptors. Our results also indicate some malfunction of the enteric nervous system in STC.

  11. How old is streamwater? Open questions in catchment transit time conceptualization, modeling and analysis

    Science.gov (United States)

    J.J. McDonnell; K. McGuire; P. Aggarwal; K.J. Beven; D. Biondi; G. Destouni; S. Dunn; A. James; J. Kirchner; P. Kraft; S. Lyon; P. Maloszewski; B. Newman; L. Pfister; A. Rinaldo; A. Rodhe; T. Sayama; J. Seibert; K. Solomon; C. Soulsby; M. Stewart; D. Tetzlaff; C. Tobin; P. Troch; M. Weiler; A. Western; A. Wörman; S. Wrede

    2010-01-01

    The time water spends travelling subsurface through a catchment to the stream network (i.e. the catchment water transit time) fundamentally describes the storage, flow pathway heterogeneity and sources of water in a catchment. The distribution of transit times reflects how catchments retain and release water and solutes that in turn set biogeochemical conditions and...

  12. Colonic fermentation may play a role in lactose intolerance in humans

    NARCIS (Netherlands)

    He, T; Priebe, MG; Harmsen, HJM; Stellaard, F; Sun, XH; Welling, GW; Vonk, RJ

    2006-01-01

    The results of our previous study suggested that in addition to the small intestinal lactase activity and transit time, colonic processing of lactose may play a role in lactose intolerance. We investigated whether colonic fermentation of lactose is correlated with lactose intolerance. After 28 Chine

  13. Blunting of Colon Contractions in Diabetics with Gastroparesis Quantified by Wireless Motility Capsule Methods.

    Science.gov (United States)

    Coleski, Radoslav; Wilding, Gregory E; Semler, John R; Hasler, William L

    2015-01-01

    Generalized gut transit abnormalities are observed in some diabetics with gastroparesis. Relations of gastric emptying abnormalities to colon contractile dysfunction are poorly characterized. We measured colon transit and contractility using wireless motility capsules (WMC) in 41 healthy subjects, 12 diabetics with gastroparesis (defined by gastric retention >5 hours), and 8 diabetics with normal gastric emptying (≤5 hours). Overall numbers of colon contractions >25 mmHg were calculated in all subjects and were correlated with gastric emptying times for diabetics with gastroparesis. Colon transit periods were divided into quartiles by time and contraction numbers were calculated for each quartile to estimate regional colon contractility. Colon transit in diabetics with gastroparesis was prolonged vs. healthy subjects (Pcontractions in gastroparetics were lower than controls (P = 0.02). Diabetics with normal emptying showed transit and contraction numbers similar to controls. Gastric emptying inversely correlated with overall contraction numbers in gastroparetics (r = -0.49). Numbers of contractions increased from the 1st to 4th colon transit quartile in controls and diabetics with normal emptying (P≤0.04), but not gastroparetics. Numbers of contractions in the 3rd and 4th quartiles were reduced in gastroparetics vs. healthy controls (P≤0.05) and in the 4th quartile vs. diabetics with normal emptying (P = 0.02). Numbers of contractions were greatest in the final 15 minutes of transit, but were reduced in gastroparetics vs. healthy controls and diabetics with normal emptying (P≤0.005). On multivariate analyses, differences in numbers of contractions were not explained by demographic or clinical variables. In conclusion, diabetics with gastroparesis exhibit delayed colon transit associated with reductions in contractions that are prominently blunted in latter transit phases and which correlate with delayed gastric emptying, while diabetics with normal emptying

  14. Effect of sennosides on colon motility in cats.

    Science.gov (United States)

    Wienbeck, M; Kortenhaus, E; Wallenfels, M; Karaus, M

    1988-01-01

    The actions of sennosides on colonic motility are incompletely understood. We therefore studied the effects of sennosides A + B on colonic myoelectric activity and transit of a radio-opaque meal in 7 conscious cats. Intraduodenal application of sennosides (2 mg/kg body weight) accelerated the half colon transit time from 60 +/- 10 (SEM) to 43 +/- 7 min. At the same time the ratio of long-spike bursts to short-spike bursts was changed from 0.22 to 10.1. Loperamide, an antidiarrheal agent, had the opposite effect. The overall spike activity was not altered by sennosides, but increased by loperamide. It is concluded that the propulsive action of sennosides in the colon is reflected by myoelectric patterns and not by the total number of spikes.

  15. Clinical validation of a real-time polymerase chain reaction assay for rapid detection of Acinetobacter baumannii colonization.

    Science.gov (United States)

    Blanco-Lobo, P; González-Galán, V; García-Quintanilla, M; Valencia, R; Cazalla, A; Martín, C; Alonso, I; Pérez-Romero, P; Cisneros, J M; Aznar, J; McConnell, M J

    2016-09-01

    Real-time polymerase chain reaction (PCR)-based approaches have not been assessed in terms of their ability to detect patients colonized by Acinetobacter baumannii during active surveillance. This prospective, double-blind study demonstrated that a real-time PCR assay had high sensitivity (100%) and specificity (91.2%) compared with conventional culture for detecting A. baumannii in 397 active surveillance samples, and provided results within 3h. Receiver-operator curve analyses demonstrated that the technique has diagnostic accuracy of 97.7% (95% confidence interval 96.0-99.3%). This method could facilitate the rapid implementation of infection control measures for preventing the transmission of A. baumannii.

  16. Two-stage resection for malignant colonic obstructions: The timing of early resection and possible predictive factors

    Institute of Scientific and Technical Information of China (English)

    Hsiang-Yu Yang; Chang-Chieh Wu; Shu-Wen Jao; Kuo-Feng Hsu; Chen-Ming Mai; Kevin Cheng-Wen Hsiao

    2012-01-01

    AIM:To study potential predictive factors for early radical resection in two-stage resection for left malignant colonic obstruction.METHODS:Thirty-eight cases of left-sided obstructive colon cancer undergoing two-stage operations were reviewed between January 1998 and August 2008.Patients were classified into two groups (n =19 each):early radical resection (interval ≤ 10 d) and late radical resection (interval > 10 d).Baseline demographics,post-diversion outcome,perioperative data,tumor characteristics,outcome and complications were analyzed.RESULTS:The baseline demographics revealed no differences except for less pre-diversion sepsis in the early group (P < 0.001) and more obstruction days in the late group (P =0.009).The mean intervals of early and late radical resections were 7.9 ± 1.3 d and 17.8 ± 5.5 d,respectively (P < 0.001).After diversion,the presence of bowel sounds,flatus,removal of the nasogastric tube and the resumption of oral feeding occurred earlier in the early group.The operation time and duration of hospital stay were both significant reduced in the early group.Complication rates did not differ between groups.CONCLUSION:The earlier recovery of bowel function seems to be predictive of early radical resection.In contrast,pre-diversion sepsis and more obstruction days were predictive of delayed radical resection.

  17. A Quantitative Real-Time PCR Approach for Assessing Campylobacter jejuni and Campylobacter coli Colonization in Broiler Herds.

    Science.gov (United States)

    Haas, Katrin; Overesch, Gudrun; Kuhnert, Peter

    2017-04-01

    Human campylobacteriosis is a major public health concern in developed countries, with Campylobacter jejuni and Campylobacter coli from poultry recognized as the main source of human infection. Identification of Campylobacter-positive broiler herds before slaughter is essential for implementing measures to avoid carryover of pathogens via the slaughter process into the food chain. However, appropriate methods that have been validated for testing poultry flocks antemortem are lacking for Campylobacter. A quantitative real-time PCR (qPCR) that allows simultaneous detection and quantification of C. jejuni and C. coli was adapted and optimized to be applied on boot socks. The adjusted qPCR serves as an easy, sensitive, and quantitative method for Campylobacter detection in poultry flocks antemortem by analysis of boot socks. An adequate correlation was found between qPCR and culture, as well as between boot socks and cecal samples, which are regarded as the "gold standard." Therefore, boot sock sampling followed by qPCR analysis provides a reliable and simple method for assessing Campylobacter load within a flock prior to slaughter. The approach allows categorization of broiler herds into negative, low, moderate, or high Campylobacter colonization. Based on the results of this new approach, risk assessment models, such as evaluating the possible effect of sorting flocks before slaughter, can be easily implemented. Similarly, targeted identification of highly colonized flocks for improvement of biosecurity measures at the farm level will become feasible, presenting an opportunity to increase food safety.

  18. Quantitative analysis of colonization with real-time PCR to identify the role of Oxalobacter formigenes in calcium oxalate urolithiasis.

    Science.gov (United States)

    Batislam, Ertan; Yilmaz, Erdal; Yuvanc, Ercan; Kisa, Ozgul; Kisa, Ucler

    2012-10-01

    The objective of the study was to quantitatively measure the number of Oxalobacter formigenes (O. formigenes) colonizations in the gastrointestinal tract in calcium oxalate-forming patients with real-time polymerase chain reaction (PCR). Calcium oxalate-forming patients (n: 27) were included in the study. Serum calcium, sodium, potassium, urea and creatinine levels, as well as 24 h urine levels of calcium and oxalate were measured. The numbers of O. formigenes colonies in stool samples were detected by real-time PCR. One or two metabolic abnormalities were detected in 15 of 27 patients. The O. formigenes levels in patients with metabolic disturbance were significantly decreased when compared to the patients with no metabolic abnormalities (p: 0.038). The undetectable levels of O. formigenes were encountered in one of five patients with hypercalciuria, in three of four patients with hyperoxaluria and in four of six patients with both hypercalciuria and hyperoxaluria. In nine patients with a history of stone recurrence, O. formigenes colonization was significantly lower than the patients with the first stone attack (p: 0.001). O. formigenes formation ceased or significantly diminished in patients with calcium oxalate stones with a coexistence of both hyperoxaluria and hypercalciuria. The measurement of O. formigenes colonies by real-time PCR seemed to be an inconvenient and expensive method. For this reason, the real-time PCR measurements can be spared for the patients with stone recurrences and with metabolic abnormalities like hypercalciuria and hyperoxaluria. The exact measurement of O. formigenes may also help more accurate programming of O. formigenes-based treatments.

  19. No Timing Variations Observed in Third Transit of Snow-line Exoplanet Kepler-421b

    Science.gov (United States)

    Dalba, Paul A.; Muirhead, Philip S.

    2016-07-01

    We observed Kepler-421 during the anticipated third transit of the snow-line exoplanet Kepler-421b in order to constrain the existence and extent of transit timing variations (TTVs). Previously, the Kepler spacecraft only observed two transits of Kepler-421b, leaving the planet’s transit ephemeris unconstrained. Our visible light, time-series observations from the 4.3 m Discovery Channel Telescope were designed to capture pre-transit baseline and the partial transit of Kepler-421b, barring significant TTVs. We use the light curves to assess the probabilities of various transit models using both the posterior odds ratio and the Bayesian Information Criterion, and find that a transit model with no TTVs is favored to 3.6σ confidence. These observations suggest that Kepler-421b is either alone in its system or is only experiencing minor dynamic interactions with an unseen companion. With the Kepler-421b ephemeris constrained, we calculate future transit times and discuss the opportunity to characterize the atmosphere of this cold, long-period exoplanet via transmission spectroscopy. Our investigation emphasizes the difficulties associated with observing long-period exoplanet transits and the consequences that arise from failing to refine transit ephemerides.

  20. Transit Timing Observations from Kepler. VI. Potentially Interesting Candidate Systems from Fourier-based Statistical Tests

    OpenAIRE

    Steffen, Jason H.; Ford, Eric B.; Rowe, Jason F.; Fabrycky, Daniel C.; Holman, Matthew J.; Welsh, William F.; Borucki, William J.; Batalha, Natalie M.; Bryson, Steve; Caldwell, Douglas A.; Ciardi, David R.; Jenkins, Jon M.; Kjeldsen, Hans; Koch, David G.; Prsa, Andrej

    2012-01-01

    We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the sy...

  1. Time needed for first lichen colonization of terminal moraines in the Tröllaskagi peninsula (North Iceland)

    Science.gov (United States)

    Andres, Nuria; Palacios, David; Brynjólfsson, Skafti; Sæmundsson, Þorsteinn

    2015-04-01

    The Tröllaskagi peninsula is located in Central North Iceland. The peninsula belong to the Tertiary basaltic areas in Iceland and is characterised by numerous glacially eroded valleys and fjords. The altitude ranges from sea level to 1500 m. Around 150 glaciers, debris covered glaciers and clean glaciers exist in the cirques of the Tröllaskagi peninsula. Lichenometric techniques were applied to date moraines formed by some of these glaciers, especially from 1970-90, establishing growth rates for some species, e.g. 0.5 mm/year for Rizocarpon geographicum. However there is no information available on how long the lichens take to colonize the boulders in a moraine once it has become detached from the retreating glacier. The aim of this paper is to observe how long it takes for the boulders on the moraines to be colonized by lichens in the Tröllaskagi peninsula, where the separation date of a moraine from the retreating glacier tongue is known. Two case studies were used. The first was the surging glacier Búrfellsjökull, in the Búrfelllsdalur valley, an affluent of the Svarfaðardalur valley. The Búrfellsjökull glacier surged in 2001-2004 and the glacial terminus advanced 150-240 m, overrunnig a moraine formed around 1955 and formed a new moraine. About 2-3 years after the surge termination in 2004 the glacial terminus was already retreating and had left the moraine isolated (Brynjólfsson et al. 2012). The other case is the Gljúlfurárjökull glacier, in the Gljúlfurárdalur valley, an affluent of the Skíðadalur valley. It can be seen from the series of aerial photographs that the glacier terminus advanced during the 1990s until the year 2000. In 2004 the glacial terminus was already retreating and had separated from a small moraine formed during the previous advance. Thus, two different glaciers halted and formed one moraine each which they separated from almost similar time. During the detailed field work carried out in August 2014 on both moraines

  2. Daylight savings time transitions and the incidence rate of unipolar depressive episodes

    DEFF Research Database (Denmark)

    Hansen, Bertel T; Sønderskov, Kim M; Hageman, Ida

    2016-01-01

    BACKGROUND: Daylight savings time transitions affect approximately 1.6 billion people worldwide. Prior studies have documented associations between daylight savings time transitions and adverse health outcomes, but it remains unknown whether they also cause an increase in the incidence rate...... of depressive episodes. This seems likely because daylight savings time transitions affect circadian rhythms, which are implicated in the etiology of depressive disorder. Therefore, we investigated the effects of daylight savings time transitions on the incidence rate of unipolar depressive episodes. METHODS......: Using time series intervention analysis of nationwide data from the Danish Psychiatric Central Research Register from 1995 to 2012 we compared the observed trend in the incidence rate of hospital contacts for unipolar depressive episodes after the transitions to and from summer time to the predicted...

  3. Regularity and stability of transition fronts in nonlocal equations with time heterogeneous ignition nonlinearity

    Science.gov (United States)

    Shen, Wenxian; Shen, Zhongwei

    2017-03-01

    The present paper is devoted to the investigation of various properties of transition fronts in one-dimensional nonlocal equations in heterogeneous media of ignition type, whose existence has been established by the authors of the present paper in a previous work. It is first shown that transition fronts are continuously differentiable in space with uniformly bounded and uniformly Lipschitz continuous space partial derivative. This is the first time that space regularity of transition fronts in nonlocal equations is ever studied. It is then shown that transition fronts are uniformly steep. Finally, asymptotic stability, in the sense of exponentially attracting front-like initial data, of transition fronts is studied.

  4. Nonparametric estimation in an "illness-death" model when all transition times are interval censored

    DEFF Research Database (Denmark)

    Frydman, Halina; Gerds, Thomas; Grøn, Randi

    2013-01-01

    We develop nonparametric maximum likelihood estimation for the parameters of an irreversible Markov chain on states {0,1,2} from the observations with interval censored times of 0 → 1, 0 → 2 and 1 → 2 transitions. The distinguishing aspect of the data is that, in addition to all transition times ...

  5. The influence of deterministic and stochastic waiting time for triggering mortality and colonization events on the coexistence of cooperators and defectors in an evolutionary game model

    Directory of Open Access Journals (Sweden)

    YouHua Chen

    2014-06-01

    Full Text Available In the present report, the coexistence of Prisoners' Dilemma game players (cooperators and defectors were explored in an individual-based framework with the consideration of the impacts of deterministic and stochastic waiting time (WT for triggering mortality and/or colonization events. For the type of deterministic waiting time, the time step for triggering a mortality and/or colonization event is fixed. For the type of stochastic waiting time, whether a mortality and/or colonization event should be triggered for each time step of a simulation is randomly determined by a given acceptance probability (the event takes place when a variate drawn from a uniform distribution [0,1] is smaller than the acceptance probability. The two strategies of modeling waiting time are considered simultaneously and applied to both quantities (mortality: WTm, colonization: WTc. As such, when WT (WTm and/or WTc is an integral >=1, it indicated a deterministically triggering strategy. In contrast, when 1>WT>0, it indicated a stochastically triggering strategy and the WT value itself is used as the acceptance probability. The parameter space between the waiting time for mortality (WTm-[0.1,40] and colonization (WTc-[0.1,40] was traversed to explore the coexistence and non-coexistence regions. The role of defense award was evaluated. My results showed that, one non-coexistence region is identified consistently, located at the area where 1>=WTm>=0.3 and 40>=WTc>=0.1. As a consequence, it was found that the coexistence of cooperators and defectors in the community is largely dependent on the waiting time of mortality events, regardless of the defense or cooperation rewards. When the mortality events happen in terms of stochastic waiting time (1>=WTm>=0.3, extinction of either cooperators or defectors or both could be very likely, leading to the emergence of non-coexistence scenarios. However, when the mortality events occur in forms of relatively long deterministic

  6. Transit time homogenization in ischemic stroke - A novel biomarker of penumbral microvascular failure?

    DEFF Research Database (Denmark)

    Engedal, Thorbjørn S; Hjort, Niels; Hougaard, Kristina D

    2017-01-01

    Cerebral ischemia causes widespread capillary no-flow in animal studies. The extent of microvascular impairment in human stroke, however, is unclear. We examined how acute intra-voxel transit time characteristics and subsequent recanalization affect tissue outcome on follow-up MRI in a historic...... cohort of 126 acute ischemic stroke patients. Based on perfusion-weighted MRI data, we characterized voxel-wise transit times in terms of their mean transit time (MTT), standard deviation (capillary transit time heterogeneity - CTH), and the CTH:MTT ratio (relative transit time heterogeneity), which...... is expected to remain constant during changes in perfusion pressure in a microvasculature consisting of passive, compliant vessels. To aid data interpretation, we also developed a computational model that relates graded microvascular failure to changes in these parameters. In perfusion-diffusion mismatch...

  7. The ethanolic extract of bark from Salix aegyptiaca L. inhibits the metastatic potential and epithelial to mesenchymal transition of colon cancer cell lines.

    Science.gov (United States)

    Enayat, Shabnam; Banerjee, Sreeparna

    2014-01-01

    Willow bark extracts have been used for centuries as a natural pain killer. Recently their potential as anticancer agents has been reported. We have shown the high antioxidant activity, phenolic and flavonoid content in the ethanolic extract of bark (EEB) from Salix aegyptiaca, a species endogenous to the Middle East. We have also reported that incubation with EEB resulted in a reduction in cell proliferation through the induction of apoptosis and cell cycle arrest via the inhibition of phosphatidyl inositol 3-kinase/Protein kinase B and mitogen activated protein kinases signaling pathways as strongly as commercial inhibitors. The current study demonstrates the robust inhibition of anchorage-independent growth, motility, migration, and adhesion of colon cancer cell lines HCT-116 and HT-29 by EEB. These in vitro functional changes were accompanied by a restoration of E-cadherin expression, a reduction in EGFR, SNAI1, SNAI2, and Twist1 and the matrix metalloproteases MMP9 and MMP2. Many of these proteins are involved in the process of epithelial to mesenchymal transition, which is considered as a critical step in the progression of noninvasive tumor cells into malignant, metastatic carcinomas. We therefore propose that EEB from Salix aegyptiaca is a potent nutraceutical causing cancer chemoprevention by inhibiting epithelial to mesenchymal transition and can be consumed for its health promoting effects.

  8. Generalizing memories over time: sleep and reinforcement facilitate transitive inference.

    Science.gov (United States)

    Werchan, Denise M; Gómez, Rebecca L

    2013-02-01

    The use of reinforcement and rewards is known to enhance memory retention. However, the impact of reinforcement on higher-order forms of memory processing, such as integration and generalization, has not been directly manipulated in previous studies. Furthermore, there is evidence that sleep enhances the integration and generalization of memory, but these studies have only used reinforcement learning paradigms and have not examined whether reinforcement impacts or is critical for memory integration and generalization during sleep. Thus, the aims of the current study were to examine: (1) whether reinforcement during learning impacts the integration and generalization of memory; and (2) whether sleep and reinforcement interact to enhance memory integration and generalization. We investigated these questions using a transitive inference (TI) task, which is thought to require the integration and generalization of disparate relational memories in order to make novel inferences. To examine whether reinforcement influences or is required for the formation of inferences, we compared performance using a reinforcement or an observation based TI task. We examined the impact of sleep by comparing performance after a 12-h delay containing either wake or sleep. Our results showed that: (1) explicit reinforcement during learning is required to make transitive inferences and that sleep further enhances this effect; (2) sleep does not make up for the inability to make inferences when reinforcement does not occur during learning. These data expand upon previous findings and suggest intriguing possibilities for the mechanisms involved in sleep-dependent memory transformation.

  9. Colon-targeted quercetin delivery using natural polymer to enhance its bioavailability.

    Science.gov (United States)

    Singhal, Anil; Jain, H; Singhal, Vipin; Elias, Edwin J; Showkat, Ahmad

    2011-01-01

    The aim of the present study is to develop a polymer (Guar Gum)-based matrix tablet (using quercetin as a model drug) with sufficient mechanical strength, and promising in vitro mouth-to-colon release profile. By definition, an oral colonic delivery system should retard drug release in the stomach and small intestine, and allow complete release in the colon. By drug delivery to the colon would therefore ensure direct treatment at the disease site, lower dosing, and fewer systemic side effects. Quercetin is antioxidant in nature and used to treat colon cancer, but they have poor absorption in the upper part of the gastrointestinal tract (GIT). As a site for drug delivery, the colon offers a near neutral pH, reduced digestive enzymatic activity, a long transit time, and an increased responsiveness to absorption enhancers. By achieving a colon-targeted drug delivery system, the absorption of quercetin may be increased, which leads to better bioactivity in fewer doses.

  10. The Barrier Method: A Technique for Calculating Very Long Transition Times

    OpenAIRE

    Adams, David A; Sander, Leonard M.; Ziff, Robert M.

    2010-01-01

    In many dynamical systems there is a large separation of time scales between typical events and "rare" events which can be the cases of interest. Rare-event rates are quite difficult to compute numerically, but they are of considerable practical importance in many fields: for example transition times in chemical physics and extinction times in epidemiology can be very long, but are quite important. We present a very fast numerical technique that can be used to find long transition times (very...

  11. Mapping the Timing, Pace, and Scale of the Fertility Transition in Brazil.

    Science.gov (United States)

    Potter, Joseph E; Schmertmann, Carl P; Assunção, Renato M; Cavenaghi, Suzana M

    2010-01-01

    Between 1960 and 2000, fertility fell sharply in Brazil, but this transition was unevenly distributed in space and time. Using Bayesian spatial statistical methods and microdata from five censuses, we develop and apply a procedure for fitting logistic curves to the fertility transitions in more than 500 small regions of Brazil over this 40-year period. Doing so enables us to map the main features of the Brazilian fertility transition in considerable detail. We detect early declines in some regions of the country and document large differences between early and late transitions in regard to both the initial level of fertility and the speed of the transition. We also use our results to test hypotheses regarding changes in the level of development at the onset of the fertility transition and identify a temporary stall in the Brazilian transition that occurred in the late 1990s. A web site with project details is at http://schmert.net/BayesLogistic.

  12. Investigation of Timing to Switch Control Mode in Powered Knee Prostheses during Task Transitions.

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    Full Text Available Current powered prosthetic legs require switching control modes according to the task the user is performing (e.g. level-ground walking, stair climbing, walking on slopes, etc.. To allow prosthesis users safely and seamlessly transition between tasks, it is critical to determine when to switch the prosthesis control mode during task transitions. Our previous study defined critical timings for different types of task transitions in ambulation; however, it is unknown whether it is the unique timing that allows safe and seamless transitions. The goals of this study were to (1 systematically investigate the effects of mode switch timing on the prosthesis user's performance in task transitions, and (2 identify appropriate timing to switch the prosthesis control mode so that the users can seamlessly transition between different locomotion tasks. Five able-bodied (AB and two transfemoral (TF amputee subjects were tested as they wore a powered knee prosthesis. The prosthesis control mode was switched manually at various times while the subjects performed different types of task transitions. The subjects' task transition performances were evaluated by their walking balance and success in performing seamless task transitions. The results demonstrated that there existed a time window within which switching the prosthesis control mode neither interrupted the subjects' task transitions nor disturbed their walking balance. Therefore, the results suggested the control mode switching of a lower limb prosthesis can be triggered within an appropriate time window instead of a specific timing or an individual phase. In addition, a generalized criterion to determine the appropriate mode switch timing was proposed. The outcomes of this study could provide important guidance for future designs of neurally controlled powered knee prostheses that are safe and reliable to use.

  13. Gastrointestinal transit times and motility in patients with cystic fibrosis

    DEFF Research Database (Denmark)

    Hedsund, Caroline; Gregersen, Tine; Jønsson, Iben

    2012-01-01

    6-107 vs. healthy: 41 min, range 4-125 (p = 0.24)), GITT (CF: 2 days, range 0.5-3.3 vs. healthy: 1.5 days, range 0.7-2.5 (p = 0.10)), right SCTT (CF: 0.5 day, range 0-1.1 vs. healthy: 0.4 day, range 0-1.0 (p = 0.85)), or left SCTT (CF: 1.0 day, range 0-2.2 vs. healthy 0.6 day, range 0.2-1.2 (p = 0.......10)). CONCLUSIONS: In spite of normal contraction patterns, overall passage through the small intestine is significantly delayed in CF patients while upper small intestinal transit may be abnormally fast....

  14. The use of transit timing to detect terrestrial-mass extrasolar planets.

    Science.gov (United States)

    Holman, Matthew J; Murray, Norman W

    2005-02-25

    Future surveys for transiting extrasolar planets are expected to detect hundreds of jovian-mass planets and tens of terrestrial-mass planets. For many of these newly discovered planets, the intervals between successive transits will be measured with an accuracy of 0.1 to 100 minutes. We show that these timing measurements will allow for the detection of additional planets in the system (not necessarily transiting) by their gravitational interaction with the transiting planet. The transit-time variations depend on the mass of the additional planet, and in some cases terrestrial-mass planets will produce a measurable effect. In systems where two planets are seen to transit, the density of both planets can be determined without radial-velocity observations.

  15. TEE, an estimator for the precision of eclipse and transit minimum times

    Science.gov (United States)

    Deeg, H. J.; Tingley, B.

    2017-03-01

    Context. Transit or eclipse timing variations have proven to be a valuable tool in exoplanet research. However, no simple way to estimate the potential precision of such timing measures has been presented yet, nor are guidelines available regarding the relation between timing errors and sampling rate. Aims: A timing error estimator (TEE) equation is presented that requires only basic transit parameters as input. With the TEE, estimating timing precision for actual data and for future instruments, such as the TESS and PLATO space missions, is straightforward. Methods: A derivation of the timing error based on a trapezoidal transit shape is given. We also verify the TEE on realistically modelled transits using Monte Carlo simulations and determine its validity range, exploring in particular the interplay between ingress/egress times and sampling rates. Results: The simulations show that the TEE gives timing errors very close to the correct value, as long as the temporal sampling is faster than transit ingress/egress durations and transits with very low S/N are avoided. Conclusions: The TEE is a useful tool for estimating eclipse or transit timing errors in actual and future data sets. In combination with a previously published equation to estimate period-errors, predictions for the ephemeris precision of long-coverage observations are possible as well. The tests for the TEE's validity range also led to implications for instrumental design. Temporal sampling has to be faster than transit ingress or egress durations, or a loss in timing precision will occur. An application to the TESS mission shows that transits close to its detection limit will have timing uncertainties that exceed 1 h within a few months of their acquisition. Prompt follow-up observations will be needed to avoid "losing" their ephemerides.

  16. Rapid change of fecal microbiome and disappearance of Clostridium difficile in a colonized infant after transition from breast milk to cow milk.

    Science.gov (United States)

    Davis, Manli Y; Zhang, Husen; Brannan, Lera E; Carman, Robert J; Boone, James H

    2016-10-07

    Clostridium difficile is the most common known cause of antibiotic-associated diarrhea. Upon the disturbance of gut microbiota by antibiotics, C. difficile establishes growth and releases toxins A and B, which cause tissue damage in the host. The symptoms of C. difficile infection disease range from mild diarrhea to pseudomembranous colitis and toxic megacolon. Interestingly, 10-50 % of infants are asymptomatic carriers of C. difficile. This longitudinal study of the C. difficile colonization in an infant revealed the dynamics of C. difficile presence in gut microbiota. Fifty fecal samples, collected weekly between 5.5 and 17 months of age from a female infant who was an asymptomatic carrier of C. difficile, were analyzed by 16S rRNA gene sequencing. Colonization switching between toxigenic and non-toxigenic C. difficile strains as well as more than 100,000-fold fluctuations of C. difficile counts were observed. C. difficile toxins were detected during the testing period in some infant stool samples, but the infant never had diarrhea. Although fecal microbiota was stable during breast feeding, a dramatic and permanent change of microbiota composition was observed within 5 days of the transition from human milk to cow milk. A rapid decline and eventual disappearance of C. difficile coincided with weaning at 12.5 months. An increase in the relative abundance of Bacteroides spp., Blautia spp., Parabacteroides spp., Coprococcus spp., Ruminococcus spp., and Oscillospira spp. and a decrease of Bifidobacterium spp., Lactobacillus spp., Escherichia spp., and Clostridium spp. were observed during weaning. The change in microbiome composition was accompanied by a gradual increase of fecal pH from 5.5 to 7. The bacterial groups that are less abundant in early infancy, and that increase in relative abundance after weaning, likely are responsible for the expulsion of C. difficile.

  17. Amount, type, and timing of recreational physical activity in relation to colon and rectal cancer in older adults: the Cancer Prevention Study II Nutrition Cohort.

    Science.gov (United States)

    Chao, Ann; Connell, Cari J; Jacobs, Eric J; McCullough, Marjorie L; Patel, Alpa V; Calle, Eugenia E; Cokkinides, Vilma E; Thun, Michael J

    2004-12-01

    Physical activity has consistently been associated with lower risk of colon cancer, but information is limited on the amount, type, and timing of activities. The relationship between physical activity and rectal cancer is unclear. We examined characteristics of recreational physical activity in relation to colon and rectal cancer in the Cancer Prevention Study II Nutrition Cohort of 70,403 men and 80,771 women (median age, 63 years); 940 colon and 390 rectal cancers were identified from enrollment in 1992 to 1993 through August 1999. The multivariate-adjusted rate ratios (95% confidence intervals) associated with any recreational physical activity compared with none were 0.87 (0.71-1.06) for colon cancer and 0.70 (0.53-0.93) for rectal cancer. Colon cancer risk decreased significantly with increasing total hours (P for trend without reference group = 0.007) and metabolic equivalent hours (P for trend = 0.006) per week of activities. No clear decrease in rectal cancer risk was seen with increasing hours per week of physical activity. Rate ratios (95% confidence intervals) were 0.72 (0.52-0.98) for /=7 hours per week of physical activity compared with none. Past exercise, as reported in 1982, was not associated with risk of either colon or rectal cancer. We conclude that increasing amounts of time spent at recreational physical activity are associated with substantially lower risk of colon cancer and that recreational physical activity is associated with lower risk of rectal cancer in older men and women.

  18. Not ready for prime time: transitional events in the extremely preterm infant.

    Science.gov (United States)

    Armentrout, Debra

    2014-01-01

    Successful transition from intrauterine to extrauterine life involves significant physiologic changes. The majority of these changes occur relatively quickly during those first moments following delivery; however, transition for the extremely preterm infant occurs over a longer period of time. Careful assessment and perceptive interventions on the part of neonatal care providers is essential as the extremely preterm infant adjusts to life outside the womb. This article will focus on respiratory, cardiovascular, gastrointestinal, and neurologic transitional events experienced by the extremely premature infant.

  19. PAC exhibits potent anti-colon cancer properties through targeting cyclin D1 and suppressing epithelial-to-mesenchymal transition.

    Science.gov (United States)

    Al-Qasem, Abeer; Al-Howail, Huda A; Al-Swailem, Mashael; Al-Mazrou, Amer; Al-Otaibi, Basem; Al-Jammaz, Ibrahim; Al-Khalaf, Huda H; Aboussekhra, Abdelilah

    2016-03-01

    Colorectal cancer (CRC) is a major cause of cancer morbidity and mortality worldwide. Although response rates and overall survival have been improved in recent years, resistance to multiple drug combinations is inevitable. Therefore, the development of more efficient drugs, with fewer side effects is urgently needed. To this end, we have investigated in the present report the effect of PAC, a novel cucumin analogue, on CRC cells both in vitro and in vivo. We have shown that PAC induces apoptosis, mainly via the internal mitochondrial route, and inhibits cell proliferation through delaying the cell cycle at G2/M phase. Interestingly, the pro-apoptotic effect was mediated through STAT3-dependent down-regulation of cyclin D1 and its downstream target survivin. Indeed, change in the expression level of cyclin D1 modulated the expression of survivin and the response of CRC cells to PAC. Furthermore, using the ChIP assay, we have shown PAC-dependent reduction in the binding of STAT3 to the cyclin D1 promoter in vivo. Additionally, PAC suppressed the epithelial-to-mesenchymal process through down-regulating the mesenchymal markers (N-cadherin, vimentin and Twist1) and inhibiting the invasion/migration abilities of the CRC cells via repressing the pro-migration/invasion protein kinases AKT and ERK1/2. In addition, PAC inhibited tumor growth and repressed the JAK2/STAT3, AKT/mTOR and MEK/ERK pathways as well as their common downstream effectors cyclin D1 and survivin in humanized CRC xenografts. Collectively, these results indicate that PAC has potent anti-CRC effects, and therefore could constitute an effective alternative chemotherapeutic agent, which may consolidate the adjuvant treatment of colon cancer.

  20. No Timing Variations Observed in Third Transit of Snow-Line Exoplanet Kepler-421b

    CERN Document Server

    Dalba, Paul A

    2016-01-01

    We observed Kepler-421 during the anticipated third transit of the snow-line exoplanet Kepler-421b in order to constrain the existence and extent of transit timing variations (TTVs). Previously, the Kepler Spacecraft only observed two transits of Kepler-421b leaving the planet's transit ephemeris unconstrained. Our visible light, time-series observations from the 4.3-meter Discovery Channel Telescope were designed to capture pre-transit baseline and the partial transit of Kepler-421b barring significant TTVs. We use the light curves to assess the probabilities of various transit models using both the posterior odds ratio and the Bayesian Information Criterion (BIC) and find that a transit model with no TTVs is favored to 3.6-sigma confidence. These observations suggest that Kepler-421b is either alone in its system or is only experiencing minor dynamic interactions with an unseen companion. With the Kepler-421b ephemeris constrained, we calculate future transit times and discuss the opportunity to characteriz...

  1. Measuring Acoustic Wave Transit Time in Furnace Based on Active Acoustic Source Signal

    Institute of Scientific and Technical Information of China (English)

    Zhen Luo; Feng Tian; Xiao-Ping Sun

    2007-01-01

    Accurate measurement of transit time for acoustic wave between two sensors installed on two sides of a furnace is a key to implementing the temperature field measurement technique based on acoustical method. A new method for measuring transit time of acoustic wave based on active acoustic source signal is proposed in this paper, which includes the followings: the time when the acoustic source signal arrives at the two sensors is measured first; then, the difference of two arriving time arguments is computed, thereby we get the transit time of the acoustic wave between two sensors installed on the two sides of the furnace. Avoiding the restriction on acoustic source signal and background noise, the new method can get the transit time of acoustic wave with higher precision and stronger ability of resisting noise interference.

  2. The role of hillslopes in stream flow response: connectivity, flow path, and transit time

    Science.gov (United States)

    McGuire, K. J.; McDonnell, J. J.

    2006-12-01

    Subsurface flow from hillslopes is widely recognized as an important contributor to stream flow generation; however, processes that control how and when hillslopes connect to streams remain unclear. Much of the difficulty in deciphering hillslope response in the stream is due to riparian zone modulation of these inputs. We investigated stream and hillslope runoff dynamics in a 10 ha catchment in the western Cascades of Oregon where the riparian zone has been removed by debris flows, providing an unambiguous hillslope hydrologic signal to the stream channel. Water transit time was used as a framework to develop a conceptual stream flow generation model for the small basin. We based our conceptualization on observations of hydrometric, stable isotope, and applied tracer responses and computed transit times for multiple runoff components using a simple linear systems model. Event water mean transit times (8 to 34 h) and rapid breakthrough from applied hillslope tracer additions, demonstrated that contributing areas extend far upslope during events. Despite rapid hillslope transport processes during events, vadose zone water and runoff mean transit times during non-storm conditions were greater than the timescale of storm events. Vadose zone water mean transit times ranged between 10 and 25 days. Hillslope seepage and catchment baseflow mean transit times were between 1 and 2 years. We describe a conceptual model that captures variable physical flow pathways and transit times through changing antecedent wetness conditions that illustrate the different stages of hillslope and stream connectivity.

  3. Solid volume fraction estimation of bone:marrow replica models using ultrasound transit time spectroscopy.

    Science.gov (United States)

    Wille, Marie-Luise; Langton, Christian M

    2016-02-01

    The acceptance of broadband ultrasound attenuation (BUA) for the assessment of osteoporosis suffers from a limited understanding of both ultrasound wave propagation through cancellous bone and its exact dependence upon the material and structural properties. It has recently been proposed that ultrasound wave propagation in cancellous bone may be described by a concept of parallel sonic rays; the transit time of each ray defined by the proportion of bone and marrow propagated. A Transit Time Spectrum (TTS) describes the proportion of sonic rays having a particular transit time, effectively describing the lateral inhomogeneity of transit times over the surface aperture of the receive ultrasound transducer. The aim of this study was to test the hypothesis that the solid volume fraction (SVF) of simplified bone:marrow replica models may be reliably estimated from the corresponding ultrasound transit time spectrum. Transit time spectra were derived via digital deconvolution of the experimentally measured input and output ultrasonic signals, and compared to predicted TTS based on the parallel sonic ray concept, demonstrating agreement in both position and amplitude of spectral peaks. Solid volume fraction was calculated from the TTS; agreement between true (geometric calculation) with predicted (computer simulation) and experimentally-derived values were R(2)=99.9% and R(2)=97.3% respectively. It is therefore envisaged that ultrasound transit time spectroscopy (UTTS) offers the potential to reliably estimate bone mineral density and hence the established T-score parameter for clinical osteoporosis assessment.

  4. The mass of the Mars-sized exoplanet Kepler-138 b from transit timing

    CERN Document Server

    Jontof-Hutter, Daniel; Lissauer, Jack J; Fabrycky, Daniel C; Ford, Eric B

    2015-01-01

    Extrasolar planets that pass in front of their host star (transit) cause a temporary decrease in the apparent brightness of the star once per orbit, providing a direct measure of the planet's size and orbital period. In some systems with multiple transiting planets, the times of the transits are measurably affected by the gravitational interactions between neighbouring planets. In favorable cases, the departures from Keplerian orbits implied by the observed transit times permit planetary masses to be measured, which is key to determining bulk densities. Characterizing rocky planets is particularly difficult, since they are generally smaller and less massive than gaseous planets. Thus, few exoplanets near Earth's size have had their masses measured. Here we report the sizes and masses of three planets orbiting Kepler-138, a star much fainter and cooler than the Sun. We measure the mass of the Mars-sized inner planet based on on the transit times of its neighbour and thereby provide the first density measuremen...

  5. Time-Varying Transition Probability Matrix Estimation and Its Application to Brand Share Analysis

    Science.gov (United States)

    Chiba, Tomoaki; Akaho, Shotaro; Murata, Noboru

    2017-01-01

    In a product market or stock market, different products or stocks compete for the same consumers or purchasers. We propose a method to estimate the time-varying transition matrix of the product share using a multivariate time series of the product share. The method is based on the assumption that each of the observed time series of shares is a stationary distribution of the underlying Markov processes characterized by transition probability matrices. We estimate transition probability matrices for every observation under natural assumptions. We demonstrate, on a real-world dataset of the share of automobiles, that the proposed method can find intrinsic transition of shares. The resulting transition matrices reveal interesting phenomena, for example, the change in flows between TOYOTA group and GM group for the fiscal year where TOYOTA group’s sales beat GM’s sales, which is a reasonable scenario. PMID:28076383

  6. Time-Varying Transition Probability Matrix Estimation and Its Application to Brand Share Analysis.

    Science.gov (United States)

    Chiba, Tomoaki; Hino, Hideitsu; Akaho, Shotaro; Murata, Noboru

    2017-01-01

    In a product market or stock market, different products or stocks compete for the same consumers or purchasers. We propose a method to estimate the time-varying transition matrix of the product share using a multivariate time series of the product share. The method is based on the assumption that each of the observed time series of shares is a stationary distribution of the underlying Markov processes characterized by transition probability matrices. We estimate transition probability matrices for every observation under natural assumptions. We demonstrate, on a real-world dataset of the share of automobiles, that the proposed method can find intrinsic transition of shares. The resulting transition matrices reveal interesting phenomena, for example, the change in flows between TOYOTA group and GM group for the fiscal year where TOYOTA group's sales beat GM's sales, which is a reasonable scenario.

  7. Transit timing observations from Kepler. VI. Potentially interesting candidate systems from fourier-based statistical tests

    DEFF Research Database (Denmark)

    Steffen, J.H.; Ford, E.B.; Rowe, J.F.

    2012-01-01

    We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through quarter six of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify...

  8. The application of GI-pill gastrointestinal electronic capsule combined with colonic transit test in patients with slow transit constipation%GI-pill胃肠电子胶囊与结肠运输试验联合检查在慢传输便秘中的应用价值

    Institute of Scientific and Technical Information of China (English)

    王永兵; 张根福; 罗芸葆; 李刚; 颜国正; 姜萍萍; 王志武

    2015-01-01

    randomly into two groups .42 cases of study group were given gastrointestinal electronic capsule and X-ray opaque granules capsule ,while 39 cases of control group were given X-ray opaque granules capsule alone .The clinical records including diet ,activation and rest would be accomplished after oral administration .The abdominal X-ray would be carried out every 24 hours until the number of residual X-ray opaque granules was less than 4.In the meantime the operating state of data recorder in vitro would be observed continuously until the electronic capsule was excreted and recycled .The results of colonic transit test in two groups would be used by case-control analysis .The records of GI-pill gastrointestinal electronic capsule including transit time in vivo , stomach, small intestine and colon , the number of HAPCs and the ratio of physiological response would be analyzed .Results In study group and control group respectively ,the average time of colonic transit test was 4.94 ±1.31 days and 4.85 ±1.35 days.The transit time of right colon,left colon and rectosigmoid was1.38 ±0.62days and 1.35 ±0.53days, 1.97 ±0.99 days and 2.02 ±0.90days,1.52 ±0.74 days and 1.58 ±0.71days respectively,which showed no significant difference .In study group the transit time of GI-pill gastrointestinal electronic capsule in vivo was 5.0 ±0.64 days and colonic transit time was 4.9 ±1.32 days.The transit time of gastrointestinal electronic capsule of stomach ,small intestine and colorectum was 5.83 ±3.12hours and 8.75 ±4.01 hours,94.7 ±17.63 hours, respectively.During the study period, there were no discomfort performances of abdominal pain ,vomiting and tarry stool in patients .Conclusions GI-pill gastrointestinal electronic capsule in good agreement with colonic transit test could be applied to assess continuously the dynamic characteristics of digestive tract in patients with slow transit constipation .It is worth popularizing application in clinic .

  9. Critical capacity, travel time delays and travel time distribution of rapid mass transit systems

    Science.gov (United States)

    Legara, Erika Fille; Monterola, Christopher; Lee, Kee Khoon; Hung, Gih Guang

    2014-07-01

    We set up a mechanistic agent-based model of a rapid mass transit system. Using empirical data from Singapore's unidentifiable smart fare card, we validate our model by reconstructing actual travel demand and duration of travel statistics. We subsequently use this model to investigate two phenomena that are known to significantly affect the dynamics within the RTS: (1) overloading in trains and (2) overcrowding in the RTS platform. We demonstrate that by varying the loading capacity of trains, a tipping point emerges at which an exponential increase in the duration of travel time delays is observed. We also probe the impact on the rail system dynamics of three types of passenger growth distribution across stations: (i) Dirac delta, (ii) uniform and (iii) geometric, which is reminiscent of the effect of land use on transport. Under the assumption of a fixed loading capacity, we demonstrate the dependence of a given origin-destination (OD) pair on the flow volume of commuters in station platforms.

  10. What do we know about the timing of fertility transitions in Europe?

    Science.gov (United States)

    Guinnane, T W; Okun, B S; Trussell, J

    1994-02-01

    The Princeton project on the decline of fertility in Europe (the European Fertility Project) suggested that this historical fertility transition occurred virtually simultaneously in a wide variety of economic and social environments. This finding has been cited widely as evidence for an innovation/diffusion view of fertility transitions. We demonstrate that the demographic methods used to date the fertility transition in Europe--primarily Ig, and (to a lesser extent) the Coale-Trussell M&m indices--may fail to detect the initial stages of a fertility transition and therefore cannot be used as the basis for strong statements about the timing of transitions. We review these measurement problems and their implications for the current understanding of the European fertility transition.

  11. Using a physically-based transit time distribution function to estimate the hydraulic parameters and hydraulic transit times of an unconfined aquifer from tritium measurements

    Science.gov (United States)

    Farlin, Julien; Maloszewski, Piotr; Schneider, Wilfried; Gallé, Tom

    2014-05-01

    Groundwater transit time is of interest in environmental studies pertaining to the transport of pollutants from its source to the aquifer outlet (spring or pumping well) or to an observation well. Different models have been proposed to describe the distribution of transit times within groundwatersheds, the most common being the dispersion model, the exponential-piston-flow model (EPM) both proposed by Maloszewski and Zuber (Maloszewski and Zuber, 1982) and the (two or three parameter) gamma model (Amin and Campana, 1996; Kirchner et al., 1999). Choosing which function applies best is a recurrent and controversial problem in hydrogeology. The object of this study is to revisit the applicability of the EPM for unconfined aquifers, and to introduce an alternative model based explicitly on groundwater hydraulics. The alternative model is based on the transit time of water from any point at the groundwater table to the aquifer outlet, and is used to calculate inversely the hydraulic parameters of a fractured unconfined sandstone aquifer from tritium measurements made in a series of contact springs. This model is compared to the EPM, which is usually adopted to describe the transit time distribution of confined and unconfined aquifers alike. Both models are tested against observations, and it is shown that the EPM fails the test for some of the springs, and generally seems to overestimate the older water component. Amin, I. E., and M. E. Campana (1996), A general lumped parameter model for the interpretation of tracer data and transit time calculation in hydrologic systems, Journal of Hydrology, 179, 1-21, doi: 10.1016/0022-1694(95)02880-3. Kirchner, J. W., X. H. Feng, and C. Neal (1999), Fractal stream chemistry and its implications for contaminant transport in catchments, Nature physics, 403, 524-527, doi: 10.1038/35000537. Maloszewski, P., and A. Zuber (1982), Determining the turnover time of groundwater systems with the aid of environmental tracers, Journal of

  12. Dual-Priced Modal Transition Systems with Time Durations

    DEFF Research Database (Denmark)

    Beneš, Nikola; Kretínsky, Jan; Larsen, Kim Guldstrand;

    2012-01-01

    intervals. We further equip the model with two kinds of quantitative aspects: each action has its own running cost per time unit, and actions may require several hardware components of different costs. We ask the question, given a fixed budget for the hardware components, what is the implementation...... with the cheapest long-run average reward. We give an algorithm for computing such optimal implementations via a reduction to a new extension of mean payoff games with time durations and analyse the complexity of the algorithm....

  13. TTVFast: An efficient and accurate code for transit timing inversion problems

    Energy Technology Data Exchange (ETDEWEB)

    Deck, Katherine M. [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States); Agol, Eric [Department of Physics and Astronomy, University of Washington at Seattle, Seattle, WA 98195 (United States); Holman, Matthew J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Nesvorný, David [Southwest Research Institute, Department of Space Studies, 1050 Walnut Street, Suite 400, Boulder, CO 80302 (United States)

    2014-06-01

    Transit timing variations (TTVs) have proven to be a powerful technique for confirming Kepler planet candidates, for detecting non-transiting planets, and for constraining the masses and orbital elements of multi-planet systems. These TTV applications often require the numerical integration of orbits for computation of transit times (as well as impact parameters and durations); frequently tens of millions to billions of simulations are required when running statistical analyses of the planetary system properties. We have created a fast code for transit timing computation, TTVFast, which uses a symplectic integrator with a Keplerian interpolator for the calculation of transit times. The speed comes at the expense of accuracy in the calculated times, but the accuracy lost is largely unnecessary, as transit times do not need to be calculated to accuracies significantly smaller than the measurement uncertainties on the times. The time step can be tuned to give sufficient precision for any particular system. We find a speed-up of at least an order of magnitude relative to dynamical integrations with high precision using a Bulirsch-Stoer integrator.

  14. Recent trend of colonic diverticulosis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yae Soon; Lee, Sung Woo; Han, Chang Yul; Lee, Kwan Seh [Inje Medical College, Seoul (Korea, Republic of)

    1988-08-15

    Colonic Diverticulosis is once thought to be a rare disease in Korea compared with western countries, but the incidence has been increasing with passage of time. Authors reviewed 151 cases of colon study with new double contrast method performed from November, 1986 to March, 1987 at Paik Hospital Inje college. The results were as follow: 1. The colonic diverticulosis was found in 39 cases out of 151 colon study (25.8%). 2. Colonic Diverticulosis were located at right and transvercolon in 54% and left and sigmoid colon in 18%. 3. Increasing occurrence in younger age group predilection; 4th decade was observed.

  15. Analysis of the Transition Time From Air to Oxy-Combustion

    Directory of Open Access Journals (Sweden)

    Lasek Janusz

    2015-03-01

    Full Text Available In this paper some issues of the transition process from air- to oxy-combustion were investigated. Advantages of flexible combustion were described. Flexible combustion tests carried out at four European plants and five plants outside Europe of different scales of process and test parameters were presented. An analysis of the transition time from air to oxy-combustion of different laboratory and pilot scale processes was carried out. The “first-order + dead time” approach was used as a model to describe transition process. Transitional periods between combustion modes and characteristic parameters of the process were determined. The transition time depends not only on the facility’s capacity but also it is impacted by specific operational parameters.

  16. On time-resolved approach for phonon assisted interband transitions

    Science.gov (United States)

    Klotins, E.

    2015-03-01

    Photoexcited dynamics of electrons and holes in two-band dielectric, with special emphasis on back reaction of phonons are developed by combining the quantum electrodynamics and Baker-Campbell-Hausdorff (BCH) canonical transformation. These methods create an explicit time-domain representation of photoinduced processes and contribute in unifying phonon-assisted description of distribution functions of electron and hole quasiparticles for the description of observable effects of photoinduced processes in dielectrics.

  17. Scintigraphic determination of small intestinal transit time: Comparison with the hydrogen breath technique

    Energy Technology Data Exchange (ETDEWEB)

    Caride, V.J.; Prokop, E.K.; Troncale, F.J.; Buddoura, W.; Winchenbach, K.; McCallum, R.W.

    1984-04-01

    The hydrogen breath test was used as a standard against which a scintigraphic method for determination of small intestinal transit time was evaluated and compared. A total of 19 male volunteers ranging in age from 23 to 28 yr participated in the study. The subjects ingested an isosmotic lactulose solution containing /sup 99m/technetium-diethylenetriaminepentaacetic acid (Sn) and then remained supine under a large field of view gamma-camera that interfaced with a computer system. Data were visually analyzed and then quantified to determine gastric emptying and small intestinal transit time. The small intestinal transit time ranged from 31 to 139 min with the scintigraphic method and 30 to 190 min with the hydrogen breath test (r . 0.77). The mean small intestinal transit time for 20 individual determinations with the scintigraphic method, 73.0 +/- 6.5 min (mean +/- SEM), was similar to the results from the hydrogen breath test technique, 75.1 +/- 8.3 min. Thirteen volunteers underwent two studies with the scintigraphic method separated by intervals ranging from 2 days to 8 wk. Individual variations in small intestinal transit time were significantly correlated with individual variations in gastric emptying (p less than 0.05). We conclude that the scintigraphic method allows accurate determination of gastrocecal time and is a noninvasive technique which may be a useful clinical test for small intestinal transit time as well as for providing information on the pathophysiology and pharmacology of intestinal motility.

  18. Transit timing, depth, and duration variation in exoplanet TrES-2?

    Directory of Open Access Journals (Sweden)

    Vaňko M.

    2011-02-01

    Full Text Available We report on our ongoing search for timing, duration, and depth variations in the exoplanet TrES-2. In Raetz et al. (2009 we already presented ten different transits obtained at the University Observatory Jena. Between November 2008 and August 2010 twelve additional transits could be observed. The timing, depth and duration of each individual event was analyzed and is presented here.

  19. An Analisys Of Transitivity Time Megazine A Case Study Of Arts Rubrics

    OpenAIRE

    Winda, Yusta Utami

    2010-01-01

    Skripsi yang berjudul An Analysis of Transitivity Process in Time Magazine: A Case Study of Arts Rubrics. Merupakan suatu kajian Linguistik Fungsional Sistemik pada majalah mingguan Time khususnya pada bidang seni. Untuk mendapatkan proses yang palind dominan digunakan formula yang dikembangkan oleh Bungin (2005,171-172). Analisis proses transitivity didalam skripsi ini menerapkan teori Linguistik Fungsional Sistemik (Systemic Functional Linguistics) yag dipelopori oleh Halliday. Proses ini d...

  20. A Matheuristic for the Liner Shipping Network Design Problem with Transit Time Restrictions

    DEFF Research Database (Denmark)

    Brouer, Berit Dangaard; Desaulniers, Guy; Karsten, Christian Vad;

    2015-01-01

    We present a mathematical model for the liner shipping network design problem with transit time restrictions on the cargo flow. We extend an existing matheuristic for the liner shipping network design problem to consider transit time restrictions. The matheuristic is an improvement heuristic, where...... on the benchmark suite LINER-LIB are reported, showing profitable networks for most instances. We provide insights on causes for rejecting demand and the average speed per vessel class in the solutions obtained....

  1. Effects of alpha-glucosidase inhibitors on mouth to caecum transit time in humans.

    OpenAIRE

    Ladas, S D; Frydas, A; Papadopoulos, A.; S. A. Raptis

    1992-01-01

    The alpha-glucosidase inhibitors acarbose and miglitol have been successfully used to control postprandial hyperglycaemia in diabetics. They probably work by slowing carbohydrate digestion and absorption, but their effect on mouth to caecum transit time has not been studied. The effect acarbose (100 mg), miglitol (100 mg), and placebo on mouth to caecum transit time (380 kcal breakfast with 20 g of lactulose) was investigated in 18 normal volunteers using breath hydrogen analysis. Both miglit...

  2. The Influence of Unpaid Work on the Transition Out of Full-Time Paid Work

    OpenAIRE

    Carr, Dawn C.; Kail, Ben Lennox

    2012-01-01

    Purpose: Continued employment after retirement and engagement in unpaid work are both important ways of diminishing the negative economic effects of the retirement of baby boomer cohorts on society. Little research, however, examines the relationship between paid and unpaid work at the transition from full-time work. Using a resource perspective framework this study examines how engagement in unpaid work prior to and at the transition from full-time work influences whether individuals partial...

  3. Transit Timing Observations from Kepler: VII. Potentially interesting candidate systems from Fourier-based statistical tests

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H.; /Fermilab; Ford, Eric B.; /Florida U.; Rowe, Jason F.; /NASA, Ames /SETI Inst., Mtn. View; Fabrycky, Daniel C.; /Lick Observ.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Welsh, William F.; /San Diego State U., Astron. Dept.; Borucki, William J.; /NASA, Ames; Batalha, Natalie M.; /San Jose State U.; Bryson, Steve; /NASA, Ames; Caldwell, Douglas A.; /NASA, Ames /SETI Inst., Mtn. View; Ciardi, David R.; /Caltech /NASA, Ames /SETI Inst., Mtn. View

    2012-01-01

    We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the systems identified in this study should prove fruitful for detailed TTV studies.

  4. Transit Timing Observations from Kepler: VII. Potentially interesting candidate systems from Fourier-based statistical tests

    CERN Document Server

    Steffen, Jason H; Rowe, Jason F; Fabrycky, Daniel C; Holman, Matthew J; Welsh, William F; Borucki, William J; Batalha, Natalie M; Bryson, Steve; Caldwell, Douglas A; Ciardi, David R; Jenkins, Jon M; Kjeldsen, Hans; Koch, David G; Prsa, Andrej; Sanderfer, Dwight T; Seader, Shawn; Twicken, Joseph D

    2012-01-01

    We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the systems identified in this study should prove fruitful for detailed TTV studies.

  5. TRANSIT TIMING OBSERVATIONS FROM KEPLER. VI. POTENTIALLY INTERESTING CANDIDATE SYSTEMS FROM FOURIER-BASED STATISTICAL TESTS

    Energy Technology Data Exchange (ETDEWEB)

    Steffen, Jason H. [Fermilab Center for Particle Astrophysics, P.O. Box 500, MS 127, Batavia, IL 60510 (United States); Ford, Eric B. [Astronomy Department, University of Florida, 211 Bryant Space Sciences Center, Gainesville, FL 32111 (United States); Rowe, Jason F.; Borucki, William J.; Bryson, Steve; Caldwell, Douglas A.; Jenkins, Jon M.; Koch, David G.; Sanderfer, Dwight T.; Seader, Shawn; Twicken, Joseph D. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Fabrycky, Daniel C. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Holman, Matthew J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Welsh, William F. [Astronomy Department, San Diego State University, San Diego, CA 92182-1221 (United States); Batalha, Natalie M. [Department of Physics and Astronomy, San Jose State University, San Jose, CA 95192 (United States); Ciardi, David R. [NASA Exoplanet Science Institute/California Institute of Technology, Pasadena, CA 91125 (United States); Kjeldsen, Hans [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Prsa, Andrej, E-mail: jsteffen@fnal.gov [Department of Astronomy and Astrophysics, Villanova University, 800 East Lancaster Avenue, Villanova, PA 19085 (United States)

    2012-09-10

    We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through quarter six of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the systems identified in this study should prove fruitful for detailed TTV studies.

  6. Transition path times reveal memory effects and anomalous diffusion in the dynamics of protein folding

    Science.gov (United States)

    Satija, Rohit; Das, Atanu; Makarov, Dmitrii E.

    2017-10-01

    Recent single-molecule experiments probed transition paths of biomolecular folding and, in particular, measured the time biomolecules spend while crossing their free energy barriers. A surprising finding from these studies is that the transition barriers crossed by transition paths, as inferred from experimentally observed transition path times, are often lower than the independently determined free energy barriers. Here we explore memory effects leading to anomalous diffusion as a possible origin of this discrepancy. Our analysis of several molecular dynamics trajectories shows that the dynamics of common reaction coordinates used to describe protein folding is subdiffusive, at least at sufficiently short times. We capture this effect using a one-dimensional fractional Brownian motion (FBM) model, in which the system undergoes a subdiffusive process in the presence of a potential of mean force, and show that this model yields much broader distributions of transition path times with stretched exponential long-time tails. Without any adjustable parameters, these distributions agree well with the transition path times computed directly from protein trajectories. We further discuss how the FBM model can be tested experimentally.

  7. Scintigraphic Small Intestinal Transit Time and Defaecography in Patients with J-Pouch

    Directory of Open Access Journals (Sweden)

    Mie Dilling Kjaer

    2015-10-01

    Full Text Available Objective methods for examination of pouch function are warranted for a better understanding of the functional result and treatment of dysfunction. The objective of this study was to evaluate the results of scintigraphic intestinal transit time and defaecography compared to the results of pouch function, mucosal condition and a questionnaire on quality of life (QoL. This cross-sectional study included 21 patients. Scintigraphic transit time and defaecography was determined with the use of Tc-99m. Pouch function was assessed by number of bowel movements, pouch volume, and continence. Pouch mucosal condition was evaluated by endoscopy and histology. Median transit time was 189 min (105–365. Median ejection fraction at defaecography (EF was 49% (3–77 and 62% (17–98 after first and second defecation. Median pouch volume was 223 mL (100–360. A median daily stool frequency of nine (4–25 was reported and three (14% patients suffered from daytime incontinence. No patients had symptomatic or endoscopic pouchitis; however, the histology showed unspecific inflammation in 19 (90% patients. There was no correlation between transit time, evacuation fraction (EF and pouch function in univariate analysis. However, we found a high body mass index (BMI and a low bowel movement frequency to be associated with a longer transit time by multivariate analysis. Scintigraphic determination of transit time and defaecography are feasible methods in patients with ileal pouch anal anastomosis, but the clinical relevance is yet doubtful.

  8. Transiting Exoplanet Monitoring Project (TEMP). II. Refined System Parameters and Transit Timing Analysis of HAT-P-33b

    Science.gov (United States)

    Wang, Yong-Hao; Wang, Songhu; Liu, Hui-Gen; Hinse, Tobias C.; Laughlin, Gregory; Wu, Dong-Hong; Zhang, Xiaojia; Zhou, Xu; Wu, Zhenyu; Zhou, Ji-Lin; Wittenmyer, R. A.; Eastman, Jason; Zhang, Hui; Hori, Yasunori; Narita, Norio; Chen, Yuanyuan; Ma, Jun; Peng, Xiyan; Zhang, Tian-Meng; Zou, Hu; Nie, Jun-Dan; Zhou, Zhi-Min

    2017-08-01

    We present 10 R-band photometric observations of eight different transits of the hot Jupiter HAT-P-33b, which has been targeted by our Transiting Exoplanet Monitoring Project. The data were obtained by two telescopes at the Xinglong Station of National Astronomical Observatories of China (NAOC) from 2013 December through 2016 January, and exhibit photometric scatter of 1.6{--}3.0 {mmag}. After jointly analyzing the previously published photometric data, radial-velocity (RV) measurements, and our new light curves, we revisit the system parameters and orbital ephemeris for the HAT-P-33b system. Our results are consistent with the published values except for the planet to star radius ratio ({R}{{P}}/{R}* ), the ingress/egress duration (τ) and the total duration (T 14), which together indicate a slightly shallower and shorter transit shape. Our results are based on more complete light curves, whereas the previously published work had only one complete transit light curve. No significant anomalies in Transit Timing Variations (TTVs) are found, and we place upper mass limits on potential perturbers, largely supplanting the loose constraints provided by the extant RV data. The TTV limits are stronger near mean-motion resonances, especially for the low-order commensurabilities. We can exclude the existence of a perturber with mass larger than 0.6, 0.3, 0.5, 0.5, and 0.3 {M}\\oplus near the 1:3, 1:2, 2:3, 3:2, and 2:1 resonances, respectively.

  9. Timing of the maturation transition in haddock Melanogrammus aeglefinus.

    Science.gov (United States)

    Tobin, D; Wright, P J; O'Sullivan, M

    2010-10-01

    The timing of maturation in haddock Melanogrammus aeglefinus was examined using changes in gonad development, follicle stimulating hormone β (FSH-β) transcript expression profile, growth and condition of 1 year old females held under a common environment between the summer and winter solstices. The circumnuclear ring, cortical alveolus and vitellogenic oocyte stages were first observed in August, October and November, respectively. FSH-β transcript levels did not change significantly until September but increased markedly thereafter in maturing fish. A combined analysis of the mean oocyte diameter of the leading cohort, histological staging and FSH-β transcript profile provided evidence of a commitment to maturation by October or November. Contrary to that previously proposed for gadoid species, histological analysis of field-caught immature M. aeglefinus during the spawning season indicated that cortical alveolar, rather than circumnuclear ring, stage oocytes provided definitive evidence of maturation. A decrease in relative liver size following the summer solstice suggested a possible link between energy status and maturation.

  10. Generation of chaotic oscillations in auto-oscillator based on avalanche transit-time diode

    Science.gov (United States)

    Myasin, E. A.

    2012-01-01

    Time series of chaotic oscillations have been observed for the first time in an auto-oscillator for the 8-mm wavelength range based on an avalanche transit-time diode. The noise generator based on this diode has been used as a signal source for a noise radar prototype.

  11. Intermittency transition to generalized synchronization in coupled time-delay systems.

    Science.gov (United States)

    Senthilkumar, D V; Lakshmanan, M

    2007-12-01

    We report the nature of the transition to generalized synchronization (GS) in a system of two coupled scalar piecewise linear time-delay systems using the auxiliary system approach. We demonstrate that the transition to GS occurs via an on-off intermittency route and that it also exhibits characteristically distinct behaviors for different coupling configurations. In particular, the intermittency transition occurs in a rather broad range of coupling strength for the error feedback coupling configuration and in a narrow range of coupling strength for the direct feedback coupling configuration. It is also shown that the intermittent dynamics displays periodic bursts of periods equal to the delay time of the response system in the former case, while they occur in random time intervals of finite duration in the latter case. The robustness of these transitions with system parameters and delay times has also been studied for both linear and nonlinear coupling configurations. The results are corroborated analytically by suitable stability conditions for asymptotically stable synchronized states and numerically by the probability of synchronization and by the transition of sub-Lyapunov exponents of the coupled time-delay systems. We have also indicated the reason behind these distinct transitions by referring to the unstable periodic orbit theory of intermittency synchronization in low-dimensional systems.

  12. Exploring business process modelling paradigms and design-time to run-time transitions

    Science.gov (United States)

    Caron, Filip; Vanthienen, Jan

    2016-09-01

    The business process management literature describes a multitude of approaches (e.g. imperative, declarative or event-driven) that each result in a different mix of process flexibility, compliance, effectiveness and efficiency. Although the use of a single approach over the process lifecycle is often assumed, transitions between approaches at different phases in the process lifecycle may also be considered. This article explores several business process strategies by analysing the approaches at different phases in the process lifecycle as well as the various transitions.

  13. Transit times and age distributions for reservoir models represented as nonlinear non-autonomuous systems

    Science.gov (United States)

    Müller, Markus; Meztler, Holger; Glatt, Anna; Sierra, Carlos

    2016-04-01

    We present theoretical methods to compute dynamic residence and transit time distributions for non-autonomous systems of pools governed by coupled nonlinear differential equations. Although transit time and age distributions have been used to describe reservoir models for a long time, a closer look to their assumptions reveals two major restrictions of generality in previous studies. First, the systems are assumed to be in equilibrium; and second, the equations under consideration are assumed to be linear. While both these assumptions greatly ease the computation and interpretation of transit time and age distributions they are not applicable to a wide range of problems. Moreover, the transfer of previous results learned from linear systems in steady state to the more complex nonlinear non-autonomous systems that do not even need to have equilibria, can be dangerously misleading. Fortunately the topic of time dependent age and transit time distributions has received some attention recently in hydrology, we aim to compute these distributions for systems of multiple reservoirs. We will discuss how storage selection functions can augment the information represented in an ODE system describing a system of reservoirs. We will present analytical and numerical algorithms and a Monte Carlo simulator to compute solutions for system transit time and age distributions for system-wide storage selection functions including the most simple, but important case of well mixed pools.

  14. Time-delayed transition of normal-to-abnormal glow in pin-to-water discharge

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S.-Y.; Byeon, Y.-S.; Yoo, S.; Hong, E. J.; Kim, S. B.; Yoo, S. J.; Ryu, S., E-mail: smryu@nfri.re.kr [Plasma Technology Research Center of National Fusion Research Institute, 37, Dongjangsan-ro, Gunsan-si, Jeollabuk-do, Gunsan 54004 (Korea, Republic of)

    2016-08-15

    Time-delayed transition of normal-to-abnormal glow was investigated in discharge between spoke-like pins and ultrapure water by applying AC-driven power at a frequency of 14.3 kHz at atmospheric pressure. The normal-to-abnormal transition can be recognized from the slope changes of current density, gas temperature, electrode temperature, and OH density. The slope changes took place in tens of minutes rather than just after discharge, in other words, the transition was delayed. The time-delay of the transition was caused by the interaction between the plasma and water. The plasma affected water properties, and then the water affected plasma properties.

  15. Scintigraphic determination of gastrointestinal transit times. A comparison with breath hydrogen and radiologic methods

    DEFF Research Database (Denmark)

    Madsen, J L; Larsen, N E; Hilsted, J;

    1991-01-01

    A scintigraphic method for determination of gastrointestinal transit times was compared with the breath hydrogen test and a multiple-bolus, single-radiograph technique. A close temporal association was found between the caecal appearance of radioactivity and the onset of breath hydrogen excretion....... In conclusion, inadequate delineation of the caecal region seems to be an unimportant drawback of the scintigraphic measurements, whereas day-to-day variation in gastrointestinal transit rates may influence the reliability of the assessments. Probably, quantitative transit data cannot be obtained from...

  16. Audit of the association between length of time spent on diagnostic work-up and tumour stage in patients with symptomatic colon cancer.

    Science.gov (United States)

    Tiong, Jimmy; Gray, Andrew; Jackson, Christopher; Thompson-Fawcett, Mark; Schultz, Michael

    2017-03-01

    Colorectal cancer is one of the most incident cancers in New Zealand. Due to resource limitations, some patients experienced protracted wait times before reaching a definitive diagnosis. We analysed the relationship between time to diagnosis and clinical stage and reviewed the length of time for components of the diagnostic work-up to identify priority areas for service improvement. We benchmarked our timeliness against introduced standards. This retrospective study included all patients with colonic (not rectal) cancer between October 2007 and September 2009. Patients were stratified into an early and advanced group. Types of delay were calculated from the onset of symptoms to the administration of treatment. The compliance with target waiting times was assessed. Fifty-eight patients were included in the early group and 83 patients in the advanced group. There were no significant differences in demographics or symptoms. The work-up was longer than international benchmarks, but with wide variations. There was no statistical difference between lengths of work-up in the groups. The advanced group had increased utilization of private and emergency investigations. Forty-four per cent met the diagnostic colonoscopy target waiting time of 42 days with a trend in favour of the advanced group and 21% received treatment within 62 days (non-significant). Current systems are not sophisticated enough to predict the stage of colon cancer. Here, long waiting times were not associated with cancer stage in symptomatic patients. Resources need to be directed to diagnostic colonic imaging. © 2014 Royal Australasian College of Surgeons.

  17. Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models

    CERN Document Server

    Fabrycky, Daniel C; Steffen, Jason H; Rowe, Jason F; Carter, Joshua A; Moorhead, Althea V; Batalha, Natalie M; Borucki, William J; Bryson, Steve; Buchhave, Lars A; Christiansen, Jessie L; Ciardi, David R; Cochran, William D; Endl, Michael; Fanelli, Michael N; Fischer, Debra; Fressin, Francois; Geary, John; Haas, Michael R; Hall, Jennifer R; Holman, Matthew J; Jenkins, Jon M; Koch, David G; Latham, David W; Li, Jie; Lissauer, Jack J; Lucas, Philip; Marcy, Geoffrey W; Mazeh, Tsevi; McCauliff, Sean; Quinn, Samuel; Ragozzine, Darin; Sasselov, Dimitar; Shporer, Avi

    2012-01-01

    Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present 4 sets of lightcurves from the Kepler spacecraft, which each show multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets' masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems' architectures, even in cases for which high-precis...

  18. A theory of lead-time in probabilistic excitation of L/H transition

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Shinichiro; Itoh, Sanae-I.; Yagi, Masatoshi [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics; Itoh, Kimitaka [National Inst. for Fusion Science, Toki, Gifu (Japan); Fukuyama, Atsushi [Kyoto Univ. (Japan). Dept. of Nuclear Engineering

    2000-07-01

    A quantity of a lead-time, t{sub lead}, is newly introduced to examine the probabilistic occurrence of the L/H transition. The lead-time is a time period during which a transition is likely to occur. We show that the lead-time has the statistical distribution as a function of the distance from critical parameter, e.g.|n{sub c} - n{sub c0}|when the density is a key parameter for transition. It has the dependence like t{sub lead} {proportional_to}|n{sub c} - n{sub c0}|{sup 2} if the background noise distribution is given as P (n{sub c}) {proportional_to}|n{sub c} - n{sub c0}|{sup -2}. (author)

  19. Transition to complete synchronization and global intermittent synchronization in an array of time-delay systems

    Science.gov (United States)

    Suresh, R.; Senthilkumar, D. V.; Lakshmanan, M.; Kurths, J.

    2012-07-01

    We report the nature of transitions from the nonsynchronous to a complete synchronization (CS) state in arrays of time-delay systems, where the systems are coupled with instantaneous diffusive coupling. We demonstrate that the transition to CS occurs distinctly for different coupling configurations. In particular, for unidirectional coupling, locally (microscopically) synchronization transition occurs in a very narrow range of coupling strength but for a global one (macroscopically) it occurs sequentially in a broad range of coupling strength preceded by an intermittent synchronization. On the other hand, in the case of mutual coupling, a very large value of coupling strength is required for local synchronization and, consequently, all the local subsystems synchronize immediately for the same value of the coupling strength and, hence, globally, synchronization also occurs in a narrow range of the coupling strength. In the transition regime, we observe a type of synchronization transition where long intervals of high-quality synchronization which are interrupted at irregular times by intermittent chaotic bursts simultaneously in all the systems and which we designate as global intermittent synchronization. We also relate our synchronization transition results to the above specific types using unstable periodic orbit theory. The above studies are carried out in a well-known piecewise linear time-delay system.

  20. High-resolution time-of-flight mass spectrometry fingerprinting of metabolites from cecum and distal colon contents of rats fed resistant starch

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Timothy J. [Ames Laboratory; Jones, Roger W. [Ames Laboratory; Ai, Yongfeng [Iowa State University; Houk, Robert S. [Ames Laboratory; Jane, Jay-lin [Iowa State University; Zhao, Yinsheng [Iowa State University; Birt, Diane F. [Iowa State University; McClelland, John F. [Ames Laboratory

    2013-12-04

    Time-of-flight mass spectrometry along with statistical analysis was utilized to study metabolic profiles among rats fed resistant starch (RS) diets. Fischer 344 rats were fed four starch diets consisting of 55 % (w/w, dbs) starch. A control starch diet consisting of corn starch was compared against three RS diets. The RS diets were high-amylose corn starch (HA7), HA7 chemically modified with octenyl succinic anhydride, and stearic-acid-complexed HA7 starch. A subgroup received antibiotic treatment to determine if perturbations in the gut microbiome were long lasting. A second subgroup was treated with azoxymethane (AOM), a carcinogen. At the end of the 8-week study, cecal and distal colon content samples were collected from the sacrificed rats. Metabolites were extracted from cecal and distal colon samples into acetonitrile. The extracts were then analyzed on an accurate-mass time-of-flight mass spectrometer to obtain their metabolic profile. The data were analyzed using partial least-squares discriminant analysis (PLS-DA). The PLS-DA analysis utilized a training set and verification set to classify samples within diet and treatment groups. PLS-DA could reliably differentiate the diet treatments for both cecal and distal colon samples. The PLS-DA analyses of the antibiotic and no antibiotic-treated subgroups were well classified for cecal samples and modestly separated for distal colon samples. PLS-DA analysis had limited success separating distal colon samples for rats given AOM from those not treated; the cecal samples from AOM had very poor classification. Mass spectrometry profiling coupled with PLS-DA can readily classify metabolite differences among rats given RS diets.

  1. Radiographic anatomy aspects and gastrointestinal transit time in Podocnemis unifilis troschel, 1848 (Testudines, Podocnemididae - doi: 10.4025/actascibiolsci.v32i4.5082 Radiographic anatomy aspects and gastrointestinal transit time in Podocnemis unifilis troschel, 1848 (Testudines, Podocnemididae. - doi: 10.4025/actascibiolsci.v32i4.5082

    Directory of Open Access Journals (Sweden)

    Fernando Moraes Machado Brito

    2010-11-01

    Full Text Available The present study analyzed the radiographic anatomy and determined the gastrointestinal transit time of Podocnemis unifilis. We used ten animals belonging to LAPAS from the Federal University of Uberlândia, Uberlândia, Minas Gerais State, Brazil. The animals were orally fed with a barium sulphate suspension at 10 mL kg-1 mixed with mineral oil, at a ratio of 70% of barium sulphate for 30% of mineral oil. Afterwards, the animals underwent radiography in a dorsum ventriloquoal position, with the X-ray device adjusted at 72 Kv and 200 mA, in time intervals to follow the permanency of contrast in the organism. Five minutes after the contrast was supplied, the stomach was filled. After sixteen hours the contrast advanced to the small intestine. In 48 hours, the whole small intestine and part of the colon were fulfilled. On the 9th day the stomach was empty and the contrast advanced to the colon. On the 11 th day, the colon was totally fulfilled, and the contrast was close to cloaca. On the 18th day all contrast was eliminated by the animal. Total time for contrast elimination was, in average, 17.6 ± 2.4 days, with the minimum of 12 and maximum of 22 days, with temperature at 27°C. The digestion of the food was slower in the duodenum, and faster in the colon-rectum, which presents lower indices of repletion.The present study analyzed the radiographic anatomy and determined the gastrointestinal transit time of Podocnemis unifilis. We used ten animals belonging to LAPAS from the Federal University of Uberlândia, Uberlândia, Minas Gerais State, Brazil. The animals were orally fed with a barium sulphate suspension at 10 mL kg-1 mixed with mineral oil, at a ratio of 70% of barium sulphate for 30% of mineral oil. Afterwards, the animals underwent radiography in a dorsum ventriloquoal position, with the X-ray device adjusted at 72 Kv and 200 mA, in time intervals to follow the permanency of contrast in the organism. Five minutes after the contrast was

  2. Study on the pulmonary mean transit time and the pulmonary blood volume by RI-cardiogram

    Energy Technology Data Exchange (ETDEWEB)

    Ushio, N.

    1987-03-01

    The pulmonary mean transit time and the pulmonary blood volume in cases of cardio-pulmonary disease were measured using Giuntini's method which is considered the most appropriate among radiocardiographic methods. The errors in this method were confirmed to be almost negligible. The results obtained were as follows: 1) The pulmonary mean transit time was related to the systemic mean transit time and markedly prolonged in left heart failure. On the other hand, it was markedly shortened in some cases of chronic pulmonary disease, particularly pulmonary emphysema. 2) The pulmonary blood volume tended to increase in left heart disorders and mitral valve disease and tended to decrease in the chronic pulmonary disease. The decrease was conspicuous particularly in some cases of pulmonary emphysema. 3) A structural change of the pulmonary vascular system in the chronic pulmonary disease appeared to bring about shortening of the pulmonary mean transit time and a decrease in the pulmonary blood volume. The pathophysiology of cardio-pulmonary disease can be more clarified by the RI-cardiogram used in this study, in which the pulmonary mean transit time and the pulmonary blood volume are used as the indicator.

  3. Long-Term Transit Timing Monitoring and Refined Light Curve Parameters of HAT-P-13b

    CERN Document Server

    Fulton, Benjamin J; Winn, Joshua N; Holman, Matthew J; Pál, András; Gazak, J Zachary

    2011-01-01

    We present 10 new transit light curves of the transiting hot Jupiter HAT-P-13b, obtained during two observational seasons by three different telescopes. When combined with 12 previously published light curves, we have a sample consisting of 22 transit light curves, spanning 1,041 days across 4 observational seasons. We use this sample to examine the recently observed large-amplitude transit timing variations (P\\'al et al. 2011), and give refined system parameters. We find that the transit times are consistent with a linear ephemeris, with the exception of a single transit time, from UT 2009 Nov 5, for which the measured mid transit time significantly deviates from our linear ephemeris. The nature of this deviation is not clear, and the rest of the data does not show any significant transit timing variation.

  4. Pulse-echo ultrasound transit time spectroscopy: A comparison of experimental measurement and simulation prediction.

    Science.gov (United States)

    Wille, Marie-Luise; Almualimi, Majdi A; Langton, Christian M

    2016-01-01

    Considering ultrasound propagation through complex composite media as an array of parallel sonic rays, a comparison of computer-simulated prediction with experimental data has previously been reported for transmission mode (where one transducer serves as transmitter, the other as receiver) in a series of 10 acrylic step-wedge samples, immersed in water, exhibiting varying degrees of transit time inhomogeneity. In this study, the same samples were used but in pulse-echo mode, where the same ultrasound transducer served as both transmitter and receiver, detecting both 'primary' (internal sample interface) and 'secondary' (external sample interface) echoes. A transit time spectrum was derived, describing the proportion of sonic rays with a particular transit time. A computer simulation was performed to predict the transit time and amplitude of various echoes created, and compared with experimental data. Applying an amplitude-tolerance analysis, 91.7% ± 3.7% of the simulated data were within ±1 standard deviation of the experimentally measured amplitude-time data. Correlation of predicted and experimental transit time spectra provided coefficients of determination (R(2)%) ranging from 100.0% to 96.8% for the various samples tested. The results acquired from this study provide good evidence for the concept of parallel sonic rays. Furthermore, deconvolution of experimental input and output signals has been shown to provide an effective method to identify echoes otherwise lost due to phase cancellation. Potential applications of pulse-echo ultrasound transit time spectroscopy include improvement of ultrasound image fidelity by improving spatial resolution and reducing phase interference artefacts.

  5. Transit time of a freely falling quantum particle in a background gravitational field

    Science.gov (United States)

    Davies, P. C. W.

    2004-12-01

    Using a model quantum clock, I evaluate an expression for the time of a non-relativistic quantum particle to transit a piecewise geodesic path in a background gravitational field with small spacetime curvature (gravity gradient), in the case in which the apparatus is in free fall. This calculation complements and extends an earlier one (Davies 2004) in which the apparatus is fixed to the surface of the Earth. The result confirms that, for particle velocities not too low, the quantum and classical transit times coincide, in conformity with the principle of equivalence. I also calculate the quantum corrections to the transit time when the de Broglie wavelengths are long enough to probe the spacetime curvature. The results are compared with the calculation of Chiao and Speliotopoulos (2003), who propose an experiment to measure the foregoing effects.

  6. Transit time of a freely falling quantum particle in a background gravitational field

    Energy Technology Data Exchange (ETDEWEB)

    Davies, P C W [Australian Centre for Astrobiology, Macquarie University, New South Wales 2109 (Australia)

    2004-12-21

    Using a model quantum clock, I evaluate an expression for the time of a non-relativistic quantum particle to transit a piecewise geodesic path in a background gravitational field with small spacetime curvature (gravity gradient), in the case in which the apparatus is in free fall. This calculation complements and extends an earlier one (Davies 2004) in which the apparatus is fixed to the surface of the Earth. The result confirms that, for particle velocities not too low, the quantum and classical transit times coincide, in conformity with the principle of equivalence. I also calculate the quantum corrections to the transit time when the de Broglie wavelengths are long enough to probe the spacetime curvature. The results are compared with the calculation of Chiao and Speliotopoulos (2003), who propose an experiment to measure the foregoing effects.

  7. Theoretical and experimental researches on C-band three-cavity transit-time effect oscillator

    Institute of Scientific and Technical Information of China (English)

    FAN Zhikai; LIU Qingxiang; CHEN Daibing; TAN Jie; ZHOU Haijing

    2004-01-01

    The C-band three-cavity transit-time effect oscillator (3C TTTO) is a novel high power microwave device based on the transit-time effect of the three-cavity (3C) resonator. The operational principle of this device is briefly expounded in this paper, and the theoretical and experimental researches on the radial insulation diode, the 3C resonator, the double-gap output cavity and the circular waveguide bevel cut radiation antenna are presented in detail. By using the analytic method, the eigen modes and their field distributions of the 3C resonator are developed, and some basic laws of the transit-time effect are obtained in non-( mode field of the 3C resonator. At last, the experimental results are given. This device generated RF peak power in excess of 400MW with 15ns FWHM, and its beam-wave power conversion efficiency is about 17%.

  8. Effect of Equal and Mismatched Signal Transition Time on Power Dissipation in Global VLSI Interconnects

    Directory of Open Access Journals (Sweden)

    Devendra Kumar Sharma

    2012-09-01

    Full Text Available High density chips have introduced problems like crosstalk noise and power dissipation. The mismatching in transition time of the inputs occurs because different lengths of interconnects lead to different parasitic values. This paper presents the analysis of the effect of equal and unequal (mismatched transition time of inputs on power dissipation in coupled interconnects. Further, the effect of signal skew on transition time is analysed. To demonstrate the effects, a model of two distributed RLC lines coupled capacitively and inductively is taken into consideration. Each interconnect line is 4mm long and terminated by capacitive load of 30fF. The analysis is carried out for simultaneously switching lines. The results are obtained through SPICE simulations and waveforms are generated.

  9. Scintigraphic small intestinal transit time and defaecography in patients with J-pouch

    DEFF Research Database (Denmark)

    Kjær, Mie Dilling; Simonsen, Jane Angel; Hvidsten, Svend;

    2015-01-01

    Objective methods for examination of pouch function are warranted for a better understanding of the functional result and treatment of dysfunction. The objective of this study was to evaluate the results of scintigraphic intestinal transit time and defaecography compared to the results of pouch...... mucosal condition was evaluated by endoscopy and histology. Median transit time was 189 min (105–365). Median ejection fraction at defaecography (EF) was 49% (3–77) and 62% (17–98) after first and second defecation. Median pouch volume was 223 mL (100–360). A median daily stool frequency of nine (4......–25) was reported and three (14%) patients suffered from daytime incontinence. No patients had symptomatic or endoscopic pouchitis; however, the histology showed unspecific inflammation in 19 (90%) patients. There was no correlation between transit time, evacuation fraction (EF) and pouch function in univariate...

  10. Dynamic detection of wake-sleep transition with reaction time-magnitude

    Institute of Scientific and Technical Information of China (English)

    Chuang Gao; Bin Chen; Wei Wei

    2009-01-01

    BACKGROUND: According to observable behaviors, sleep and wakefulness are two fundamentally different behavioral states. Although electroencephalogram (EEG) is traditionally used to define sleep stage, it is difficult to detect or to quantify microarousals or disruptions during sleep. In addition,initial sleep cannot be defined. It is thought that the wake-sleep transition cannot be defined by EEG patterns.OBJECTIVE: To observe the behavioral response magnitude during wake-sleep transition by EEG monitoring and to define the wake-sleep transition.DESIGN, TIME AND SE'n'ING: A behavioral and neural network study was performed at the Key Lab of Human Being Development and Mental Health of Central China Normal University, and Lab of Brain and Cognitive Science of South Central University for Nationalities, China in July 2007.PARTICIPANTS: A total of 30 healthy volunteers, of equal gender and aged (19.7+1.1) years, were recruited from the Central China Normal University, China for this study. None of the subjects had undergone EEG recording prior to this study or received any medication for sleep disturbances.METHODS: A novel adaptive approach was applied to detect wake-sleep transition, which avoided stimulus-induced waking. To test the difference between wake state and wake-sleep transition, the amount of self-information and mutual-information were effective parameters to analyze wake-sleep transition.MAIN OUTCOME MEASURES: The following parameters were measured: morphological changes in reaction time-magnitude, as well as correlation between phase changes and sleep, and wake and wake-sleep transition.RESULTS: There were three typical phases in morphological changes of reaction time-magnitude.With regard to the behavioral definition and criterion for sleep, the phase morphological characteristics displayed good correlation with behavioral states, such as sleep, wakefulness, and sleep onset. Entropy as an indicator of brain cognitive processes was introduced to test

  11. Nonlinear light behaviors near phase transition in non-parity-time-symmetric complex waveguides

    CERN Document Server

    Nixon, Sean

    2016-01-01

    Many classes of non-parity-time (PT) symmetric waveguides with arbitrary gain and loss distributions still possess all-real linear spectrum or exhibit phase transition. In this article, nonlinear light behaviors in these complex waveguides are probed analytically near a phase transition. Using multi-scale perturbation methods, a nonlinear ordinary differential equation (ODE) is derived for the light's amplitude evolution. This ODE predicts that the first class of these non-PT-symmetric waveguides support continuous families of solitons and robust amplitude-oscillating solutions both above and below phase transition, in close analogy with PT-symmetric systems. For the other classes of waveguides, the light's intensity always amplifies under the effect of nonlinearity even if the waveguide is below phase transition. These analytical predictions are confirmed by direct computations of the full system.

  12. Reconciling transition path time and rate measurements in reactions with large entropic barriers

    Science.gov (United States)

    Makarov, Dmitrii E.

    2017-02-01

    Recent experiments and simulation studies showed that protein/DNA folding barriers inferred from folding rates or from potentials of mean force are often much higher than the barriers estimated from the distributions of transition path times. Here a toy model is used to explain a possible origin of this effect: It is shown that when the transition in question involves an entropic barrier, the one-dimensional Langevin model commonly used to interpret experimental data, while adequately predicting the transition rate, fails to describe the properties of the subset of the trajectories that form the transition path ensemble; the latter may still be describable in terms of a one-dimensional model, but with a different potential, just as observed experimentally.

  13. Changes of the colonic physiologic functions after colonic anastomosis with a degradable stent in a porcine model

    Institute of Scientific and Technical Information of China (English)

    Feng Xu; Liang Xiao; Wang Yifan; He Shilin; Cai Xiujun

    2014-01-01

    Background A new procedure of colonic anastomosis with a degradable stent has already been proven to be simple,feasible,and safe in our porcine model.In this study,we evaluated its impact on the colonic physiologic functions.Methods A total of 20 pigs were assigned randomly to either a stent anastomosis group (SA,n=10) or a conventional anastomosis group (CA,n=10).Colonic anastomosis with a degradable stent was performed in the SA group,and conventional hand-sewn anastomosis was performed in the CA group.Body weight,fecal weight,total colonic transit time,immunohistochemistry staining of interstitial cells of Cajal (ICC),plasma diamine oxidases (DAO) levels,and Western blotting analysis of occludin were evaluated before and after anastomosis.Results No obvious diarrhea or constipation was observed in all pigs.No significant difference in body weight between the groups was detected at any time.Yet,the fecal weight was less in the CA group compared with the SA group on postoperative day (POD) 7.No observable colonic paralysis or retention occurred.For total colonic transit time,there was no significant difference between the two groups at any time or among different time points in the same group.The integrated optical density of ICC showed no significant difference on either POD 14 or 30.The plasma DAO levels were remarkably elevated after surgery,and began to decrease since POD 3.However,there was no significant difference between both two groups in plasma DAO levels at any time either.For both groups,the expression of occludin was not significantly different from their pre-surgery level on either POD 14 or 30.Conclusions According to these results,this procedure with a degradable stent was supposed to be the same as the conventional hand-sewn procedure in their impact on the colonic physiologic functions.

  14. Colonic angiodysplasia

    Energy Technology Data Exchange (ETDEWEB)

    Vallee, C.; Legmann, P.; Garnier, T.; Levesque, M.; Favriel, J.M.

    1984-11-01

    The main clinical, endoscopic and radiographic findings in thirty documented cases of colonic angiodysplasia or vacular ectasia are described. We emphasise the association with colonic diverticulosis and cardiovascular pathology, describe the histological changes, summarize the present physiopathological hypothesis, and consider the various therapeutic approaches.

  15. Colonic locomotion

    NARCIS (Netherlands)

    Dodou, D.

    2006-01-01

    The most effective screening method for colonic cancer is colonoscopy. However, colonoscopy cannot be easily embraced by the population because of the related pain intensity. Robotic devices that pull themselves forward through the colon are a possible alternative. The main challenge for such device

  16. Mean transit times in contrasting headwater catchments from southeast Australia determined using Tritium

    Science.gov (United States)

    Cartwright, Ian; Morgenstern, Uwe; Irvine, Dylan

    2016-04-01

    Headwater streams contribute a significant proportion of the total discharge of many river systems. However, despite their importance, the time taken for rainfall to pass through the catchment into the streams (the transit time) in headwater catchments is largely unknown as are the catchment characteristics (such as drainage density, topography, landuse, or geology) that determine variations in transit times. Because the peak in Tritium activities in rainfall produced by atmospheric nuclear tests in the1950's and 1960's (the "bomb-pulse") was several orders of magnitude lower in the southern hemisphere than in the northern hemisphere, Tritium activities of remnant bomb pulse water in the southern hemisphere have decayed below those of modern rainfall. This allows mean transit times to be estimated from single Tritium measurements. Here we use Tritium to estimate transit times of water contributing to perennial streams in the adjacent upper catchments of the Yarra and Latrobe Rivers (southeast Australia). Samples were collected at varying flow from six headwater tributary sites in the Latrobe catchment, which is largely forested and four tributaries in the Yarra catchment which has been extensively cleared for dryland agriculture. The lowest Tritium activities were recorded during summer baseflow conditions and are between 1.25 and 1.75 TU, these are significantly below the Tritium activity of local rainfall (~2.8 TU). Mean transit times calculated using an exponential-piston flow lumped parameter model are 21 to 47 years. Tritium activities during the recession periods following winter high flows are higher (1.54 to 2.1 TU), which may reflect either the dilution of a baseflow component with recent surface runoff or mobilisation of different stores of water with different residence times (e.g., from the soils or the regolith) from within the catchment. The variation of major ion concentrations with discharge suggests it is more likely that that different stores of

  17. Dwell Time Modelling and Optimized Simulations for Crowded Rail Transit Lines Based on Train Capacity

    Directory of Open Access Journals (Sweden)

    Zhibin Jiang

    2015-04-01

    Full Text Available Understanding the nature of rail transit dwell time has potential benefits for both the users and the operators. Crowded passenger trains cause longer dwell times and may prevent some passengers from boarding the first available train that arrives. Actual dwell time and the process of passenger alighting and boarding are interdependent through the sequence of train stops and propagated delays. A comprehensive and feasible dwell time simulation model was developed and optimized to address the problems associated with scheduled timetables. The paper introduces the factors that affect dwell time in urban rail transit systems, including train headway, the process and number of passengers alighting and boarding the train, and the inability of train doors to properly close the first time because of overcrowded vehicles. Finally, based on a time-driven micro-simulation system, Shanghai rail transit Line 8 is used as an example to quantify the feasibility of scheduled dwell times for different stations, directions of travel and time periods, and a proposed dwell time during peak hours in several crowded stations is presented according to the simulation results.

  18. Markov Model of Wind Power Time Series UsingBayesian Inference of Transition Matrix

    DEFF Research Database (Denmark)

    Chen, Peiyuan; Berthelsen, Kasper Klitgaard; Bak-Jensen, Birgitte

    2009-01-01

    This paper proposes to use Bayesian inference of transition matrix when developing a discrete Markov model of a wind speed/power time series and 95% credible interval for the model verification. The Dirichlet distribution is used as a conjugate prior for the transition matrix. Three discrete Markov...... models are compared, i.e. the basic Markov model, the Bayesian Markov model and the birth-and-death Markov model. The proposed Bayesian Markov model shows the best accuracy in modeling the autocorrelation of the wind power time series....

  19. Effect of electrical forepaw stimulation on capillary transit-time heterogeneity (CTH)

    DEFF Research Database (Denmark)

    Gutiérrez-Jiménez, Eugenio; Cai, Changsi; Mikkelsen, Irene Klærke;

    2016-01-01

    microvascular networks. Electrical forepaw stimulation reduced, both mean transit time (11.3% ± 1.3%) and capillary transit-time heterogeneity (24.1% ± 3.3%), consistent with earlier literature and model predictions. We observed a coefficient of variance reduction (14.3% ± 3.5%) during functional activation......, especially for the arteriolar-to-venular passage. Such coefficient of variance reduction during functional activation suggests homogenization of capillary flows beyond that expected as a passive response to increased blood flow by other stimuli. This finding is consistent with an active neurocapillary...

  20. Nonlinear ion dynamics in Hall thruster plasma source by ion transit-time instability

    Science.gov (United States)

    Lim, Youbong; Choe, Wonho; Mazouffre, Stéphane; Park, Jae Sun; Kim, Holak; Seon, Jongho; Garrigues, L.

    2017-03-01

    High-energy tail formation in an ion energy distribution function (IEDF) is explained in a Hall thruster plasma with the stationary crossed electric and magnetic fields whose discharge current is oscillated at the ion transit-time scale with a frequency of 360 kHz. Among ions in different charge states, singly charged Xe ions (Xe+) have an IEDF that is significantly broadened and shifted toward the high-energy side, which contributes to tail formation in the entire IEDF. Analytical and numerical investigations confirm that the IEDF tail is due to nonlinear ion dynamics in the ion transit-time oscillation.

  1. Pectin matrix as oral drug delivery vehicle for colon cancer treatment.

    Science.gov (United States)

    Wong, Tin Wui; Colombo, Gaia; Sonvico, Fabio

    2011-03-01

    Colon cancer is the fourth most common cancer globally with 639,000 deaths reported annually. Typical chemotherapy is provided by injection route to reduce tumor growth and metastasis. Recent research investigates the oral delivery profiles of chemotherapeutic agents. In comparison to injection, oral administration of drugs in the form of a colon-specific delivery system is expected to increase drug bioavailability at target site, reduce drug dose and systemic adverse effects. Pectin is suitable for use as colon-specific drug delivery vehicle as it is selectively digested by colonic microflora to release drug with minimal degradation in upper gastrointestinal tract. The present review examines the physicochemical attributes of formulation needed to retard drug release of pectin matrix prior to its arrival at colon, and evaluate the therapeutic value of pectin matrix in association with colon cancer. The review suggests that multi-particulate calcium pectinate matrix is an ideal carrier to orally deliver drugs for site-specific treatment of colon cancer as (1) crosslinking of pectin by calcium ions in a matrix negates drug release in upper gastrointestinal tract, (2) multi-particulate carrier has a slower transit and a higher contact time for drug action in colon than single-unit dosage form, and (3) both pectin and calcium have an indication to reduce the severity of colon cancer from the implication of diet and molecular biology studies. Pectin matrix demonstrates dual advantages as drug carrier and therapeutic for use in treatment of colon cancer.

  2. Detection of Earth-mass and Super-Earth Trojan Planets Using Transit Timing Variation Method

    CERN Document Server

    Haghighipour, Nader; Hinse, Tobias C

    2013-01-01

    We have carried out an extensive study of the possibility of the detection of Earth-mass and super-Earth Trojan planets using transit timing variation method with the Kepler space telescope. We have considered a system consisting of a transiting Jovian-type planet in a short period orbit, and determined the induced variations in its transit timing due to an Earth-mass/super-Earth Trojan planet. We mapped a large section of the phase space around the 1:1 mean-motion resonance and identified regions corresponding to several other mean-motion resonances where the orbit of the planet would be stable. We calculated TTVs for different values of the mass and orbital elements of the transiting and perturbing bodies as well as the mass of central star, and identified orbital configurations of these objects (ranges of their orbital elements and masses) for which the resulted TTVs would be within the range of the variations of the transit timing of Kepler's planetary candidates. Results of our study indicate that in gen...

  3. Hydroclimatic influences on non-stationary transit time distributions in a boreal headwater catchment

    Science.gov (United States)

    Peralta-Tapia, A.; Soulsby, C.; Tetzlaff, D.; Sponseller, R.; Bishop, K.; Laudon, H.

    2016-12-01

    Understanding how water moves through catchments - from the time it enters as precipitation to when it exits via streamflow - is of fundamental importance to understanding hydrological and biogeochemical processes. A basic descriptor of this routing is the Transit Time Distribution (TTD) which is derived from the input-output behavior of conservative tracers, the mean of which represents the average time elapsed between water molecules entering and exiting a flow system. In recent decades, many transit time studies have been conducted, but few of these have focused on snow-dominated catchments. We assembled a 10-year time series of isotopic data (δ18O and δ2H) for precipitation and stream water to estimate the characteristics of the transit time distribution in a boreal catchment in northern Sweden. We applied lumped parameter models using a gamma distribution to calculate the Mean Transit Time (MTT) of water over the entire period of record and to evaluate how inter-annual differences in transit times relate to hydroclimatic variability. The best fit MTT for the complete 10-year period was 650 days (Nash-Sutcliff Efficiency = 0.65), while the best fit inter-annual MTT ranged from 300 days up to 1200 days. Whilst there was a weak negative correlation between mean annual total precipitation and the annual MTT, this relationship was stronger (r2 = 0.53, p = 0.02) for the annual rain water input. This strong connection between the MTT and annual rainfall, rather than snowmelt, has strong implications for understanding future hydrological and biogeochemical processes in boreal regions, given that predicted warmer winters would translate into a greater proportion of precipitation falling as rain and thus shorter MTT in catchments. Such a change could have direct implications for the export of solutes and pollutants.

  4. Time-dependent Mott transition in the periodic Anderson model with nonlocal hybridization

    Science.gov (United States)

    Hofmann, Felix; Potthoff, Michael

    2016-08-01

    The time-dependent Mott transition in a periodic Anderson model with off-site, nearest-neighbor hybridization is studied within the framework of nonequilibrium self-energy functional theory. Using the two-site dynamical-impurity approximation, we compute the real-time dynamics of the optimal variational parameter and of different observables initiated by sudden quenches of the Hubbard-U and identify the critical interaction. The time-dependent transition is orbital selective, i.e., in the final state, reached in the long-time limit after the quench to the critical interaction, the Mott gap opens in the spectral function of the localized orbitals only. We discuss the dependence of the critical interaction and of the final-state effective temperature on the hybridization strength and point out the various similarities between the nonequilibrium and the equilibrium Mott transition. It is shown that these can also be smoothly connected to each other by increasing the duration of a U-ramp from a sudden quench to a quasi-static process. The physics found for the model with off-site hybridization is compared with the dynamical Mott transition in the single-orbital Hubbard model and with the dynamical crossover found for the real-time dynamics of the conventional Anderson lattice with on-site hybridization.

  5. Evaluation of chemical composition, antioxidant, antibacterial, cytotoxic and apoptotic effects of Aloysia citrodora extract on colon cancer cell line using Real Time PCR and Flow-cytometry methods

    Directory of Open Access Journals (Sweden)

    Amir Mirzaie

    2016-06-01

    Full Text Available Background and aims: Aloysia citrodora belongs to the Verbenaceae family of plants, a well-known herbal medicine in Iran. The aim of the present study was to investigate the chemical composition, antioxidant, antibacterial, cytotoxic and apoptotic effect of A. citrodora extract against human colon cancer using real time PCR and flow cytometry methods. Materials and Methods: this experimental study was carried out in Islamic Azad University, East Tehran Branch, from March to September of 2014. At first, the A. citrodora chemical constituents were analyzed by GC/MS technique. In addition, antioxidant assay, antibacterial and anti-cancer effect was performed using DPPH, disk diffusion and MTT methods, respectively. Finally, the apoptosis gene (Bax and Bcl2 expression was performed by real time PCR and apoptotic effects was analyzed using Flow-cytometry technique. Results:  GC/MS analysis of A. citrodora extract was shown 37 major components and the most frequent component was belonged to Spathulenol (17.57% and Caryophyllene oxide (15.15%. The antioxidant activity of the extract was IC50=0.6 ±0.03. The maximum and minimum antibacterial effects of extract were belonged to Gram negative and Gram positive bacteria, respectively. Cytotoxic results revealed that the extract have IC50= 20.1± 0.78 mg/ml against colon cell line and Real Time PCR results showed the expression level of Bax and Bcl2 was increased and decreased respectively in colon cancer cell line (3.470 ± 0.72 (P<0.05, 0.43 ± 0.35 (P< 0.05. In addition, the flow-cytometry results indicated the 38.66 % apoptosis in colon cancer cell line. Conclusion: According to the results, it seems that A. citrodora extract has potential uses for pharmaceutical industries and it suggested that further studies were performed for A. citrodora pharmaceutical importance.

  6. Time-resolved small-angle neutron scattering of a micelle-to-vesicle transition

    Energy Technology Data Exchange (ETDEWEB)

    Egelhaaf, S.U. [Institut Max von Laue - Paul Langevin (ILL), 38 -Grenoble (France); Schurtenberger, P. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-04-01

    Amphiphilic molecules spontaneously self-assemble in solution to form a variety of aggregates. Only limited information is available on the kinetics of the structural transitions as well as on the existence of non-equilibrium or metastable states. Aqueous mixtures of lecithin and bile salt are very interesting biological model-systems which exhibit a spontaneous transition from polymer-like mixed micelles to vesicles upon dilution. The small-angle neutron scattering (SANS) instrument D22, with its very high neutron flux and the broad range of scattering vectors covered in a single instrumental setting, allowed us for the first time to perform time-resolved scattering experiments in order to study the micelle-to-vesicle transition. The temporal evolution of the aggregate structures were followed and detailed information was obtained even on molecular length-scales. (author). 5 refs.

  7. Measurement of planet masses with transit timing variations due to synodic "chopping" effects

    CERN Document Server

    Deck, Katherine M

    2014-01-01

    Gravitational interactions between planets in transiting exoplanetary systems lead to variations in the times of transit that are diagnostic of the planetary masses and the dynamical state of the system. Here we show that synodic "chopping" contributions to these transit timing variations (TTVs) can be used to uniquely measure the masses of planets without full dynamical analyses involving direct integration of the equations of motion. We present simple analytic formulae for the chopping signal, which are valid (generally <10% error) for modest eccentricities e <~ 0.1. Importantly, these formulae primarily depend on the mass of the perturbing planet, and therefore the chopping signal can be used to break the mass/free-eccentricity degeneracy which can appear for systems near first order mean motion resonances. Using a harmonic analysis, we apply these TTV formulae to a number of Kepler systems which had been previously analyzed with full dynamical analyses. We show that when chopping is measured, the ma...

  8. Direct measurement of sequence-dependent transition path times and conformational diffusion in DNA duplex formation.

    Science.gov (United States)

    Neupane, Krishna; Wang, Feng; Woodside, Michael T

    2017-02-07

    The conformational diffusion coefficient, D, sets the timescale for microscopic structural changes during folding transitions in biomolecules like nucleic acids and proteins. D encodes significant information about the folding dynamics such as the roughness of the energy landscape governing the folding and the level of internal friction in the molecule, but it is challenging to measure. The most sensitive measure of D is the time required to cross the energy barrier that dominates folding kinetics, known as the transition path time. To investigate the sequence dependence of D in DNA duplex formation, we measured individual transition paths from equilibrium folding trajectories of single DNA hairpins held under tension in high-resolution optical tweezers. Studying hairpins with the same helix length but with G:C base-pair content varying from 0 to 100%, we determined both the average time to cross the transition paths, τtp, and the distribution of individual transit times, PTP(t). We then estimated D from both τtp and PTP(t) from theories assuming one-dimensional diffusive motion over a harmonic barrier. τtp decreased roughly linearly with the G:C content of the hairpin helix, being 50% longer for hairpins with only A:T base pairs than for those with only G:C base pairs. Conversely, D increased linearly with helix G:C content, roughly doubling as the G:C content increased from 0 to 100%. These results reveal that G:C base pairs form faster than A:T base pairs because of faster conformational diffusion, possibly reflecting lower torsional barriers, and demonstrate the power of transition path measurements for elucidating the microscopic determinants of folding.

  9. Hypofractionated Irradiation Has Immune Stimulatory Potential and Induces a Timely Restricted Infiltration of Immune Cells in Colon Cancer Tumors

    Science.gov (United States)

    Frey, Benjamin; Rückert, Michael; Weber, Julia; Mayr, Xaver; Derer, Anja; Lotter, Michael; Bert, Christoph; Rödel, Franz; Fietkau, Rainer; Gaipl, Udo S.

    2017-01-01

    In addition to locally controlling the tumor, hypofractionated radiotherapy (RT) particularly aims to activate immune cells in the RT-modified microenvironment. Therefore, we examined whether hypofractionated RT can activate dendritic cells (DCs), induce immune cell infiltration in tumors, and how the chronology of immune cell migration into tumors occurs to gain knowledge for future definition of radiation breaks and inclusion of immunotherapy. Colorectal cancer treatments offer only limited survival benefit, and immunobiological principles for additional therapies need to be explored with preclinical models. The impact of hypofractionated RT on CT26 colon cancer tumor cell death, migration of DCs toward supernatants (SN) of tumor cells, and activation of DCs by SN were analyzed. The subcutaneous tumor of a BALB/c-CT26 mouse model was locally irradiated with 2 × 5 Gy, the tumor volume was monitored, and the infiltration of immune cells in the tumor was determined by flow cytometry daily. Hypofractionated RT induced a mixture of apoptotic and necrotic CT26 cells, which is known to be in particular immunogenic. DCs that migrated toward SN of CT26 cells particularly upregulated the activation markers CD80 and CD86 when in contact with SN of irradiated tumor cells. After hypofractionated RT, the tumor outgrowth was significantly retarded and in the irradiated tumors an increased infiltration of macrophages (CD11bhigh/F4-80+) and DCs (MHC-II+), but only between day 5 and 10 after the first irradiation, takes place. While CD4+ T cells migrated into non-irradiated and irradiated tumors, CD8+ T cells were only found in tumors that had been irradiated and they were highly increased at day 8 after the first irradiation. Myeloid-derived suppressor cells and regulatory T cells show regular turnover in irradiated and non-irradiated tumors. Tumor cell-specific anti-IgM antibodies were enhanced in the serum of animals with irradiated tumors. We conclude that

  10. Accuracy of a rapid real-time polymerase chain reaction assay for diagnosis of group B Streptococcus colonization in a cohort of HIV-infected pregnant women.

    Science.gov (United States)

    Gouvea, Maria Isabel S; Joao, Esau C; Teixeira, Maria de Lourdes B; Read, Jennifer S; Fracalanzza, Sergio E L; Souza, Claudia T V; Souza, Maria José de; Torres Filho, Helio M; Leite, Cassiana C F; do Brasil, Pedro E A A

    2017-05-01

    There are limited data regarding Xpert performance to detect Group B Streptococcus (GBS) in HIV-infected pregnant women. We evaluated the accuracy of a rapid real-time polymerase chain reaction (PCR) test in a cohort of HIV-infected women. At 35-37 weeks of pregnancy, a pair of combined rectovaginal swabs were collected for two GBS assays in a cohort of sequentially included HIV-infected women in Rio de Janeiro: (1) culture; and (2) real-time PCR assay [GeneXpert GBS (Cepheid, Sunnyvale, CA)]. Using culture as the reference, sensitivity, specificity, positive and negative-likelihood ratios were estimated. From June 2012 to February 2015, 337 pregnant women met inclusion criteria. One woman was later excluded, due to failure to obtain a result in the index test; 336 were included in the analyses. The GBS colonization rate was 19.04%. Sensitivity and specificity of the GeneXpert GBS assay were 85.94% (95% CI: 75.38-92.42) and 94.85% (95% CI: 91.55-96.91), respectively. Positive and negative predictive values were 79.71% (95% CI: 68.78-87.51) and 96.63% (95% CI: 93.72-98.22), respectively. GeneXpert GBS is an acceptable test for the identification of GBS colonization in HIV-infected pregnant women and represents a reasonable option to detect GBS colonization in settings where culture is not feasible.

  11. Predicting Coronal Mass Ejections transit times to Earth with neural network

    CERN Document Server

    Sudar, D; Dumbović, M

    2015-01-01

    Predicting transit times of Coronal Mass Ejections (CMEs) from their initial parameters is a very important subject, not only from the scientific perspective, but also because CMEs represent a hazard for human technology. We used a neural network to analyse transit times for 153 events with only two input parameters: initial velocity of the CME, $v$, and Central Meridian Distance, CMD, of its associated flare. We found that transit time dependence on $v$ is showing a typical drag-like pattern in the solar wind. The results show that the speed at which acceleration by drag changes to deceleration is $v\\approx$500 km s$^{-1}$. Transit times are also found to be shorter for CMEs associated with flares on the western hemisphere than those originating on the eastern side of the Sun. We attribute this difference to the eastward deflection of CMEs on their path to 1 AU. The average error of the NN prediction in comparison to observations is $\\approx$12 hours which is comparable to other studies on the same subject.

  12. Time-delay effects on the aging transition in a population of coupled oscillators.

    Science.gov (United States)

    Thakur, Bhumika; Sharma, Devendra; Sen, Abhijit

    2014-10-01

    We investigate the influence of time-delayed coupling on the nature of the aging transition in a system of coupled oscillators that have a mix of active and inactive oscillators, where the aging transition is defined as the gradual loss of collective synchrony as the proportion of inactive oscillators is increased. We start from a simple model of two time-delay coupled Stuart-Landau oscillators that have identical frequencies but are located at different distances from the Hopf bifurcation point. A systematic numerical and analytic study delineates the dependence of the critical coupling strength (at which the system experiences total loss of synchrony) on time delay and the average distance of the system from the Hopf bifurcation point. We find that time delay can act to facilitate the aging transition by lowering the threshold coupling strength for amplitude death in the system. We then extend our study to larger systems of globally coupled active and inactive oscillators including an infinite system in the thermodynamic limit. Our model system and results can provide a useful paradigm for understanding the functional robustness of diverse physical and biological systems that are prone to aging transitions.

  13. Dating Violence, Bullying, and Sexual Harassment: Longitudinal Profiles and Transitions over Time

    Science.gov (United States)

    Miller, Shari; Williams, Jason; Cutbush, Stacey; Gibbs, Deborah; Clinton-Sherrod, Monique; Jones, Sarah

    2013-01-01

    Although there is growing recognition of the problem of dating violence, little is known about how it unfolds among young adolescents who are just beginning to date. This study examined classes (subgroups) and transitions between classes over three time points based on dating violence, bullying, and sexual harassment perpetration and victimization…

  14. Validation of a 1-mm transit time flow probe and the potential for use in microsurgery

    DEFF Research Database (Denmark)

    Bonde, Christian T; Elberg, Jens J; Holstein-Rathlou, N.-H.

    2006-01-01

    The objective of this study was to validate a prototype transit time ultrasound flow probe (Medi-Stim Butterfly Flowmeter BF 2004) of only 1 mm and to evaluate its potential for use in microsurgery. Knowledge of the ability of this kind of system to measure flow in small vessels and at small flow...

  15. Transit Timing Observations from Kepler. IX. Catalog of the Full Long-Cadence Data Set

    CERN Document Server

    Holczer, Tomer; Nachmani, Gil; Jontof-Hutter, Daniel; Ford, Eric B; Fabrycky, Daniel; Ragozzine, Darin; Kane, Mackenzie; Steffen, Jason H

    2016-01-01

    We present a new transit timing catalog of 2599 Kepler Objects of Interest (=KOIs), using the PDC-MAP long-cadence light curves that include the full seventeen quarters of the mission (ftp://wise- ftp.tau.ac.il/pub/tauttv/TTV/ver_112). The goal is to produce an easy-to-use catalog that can stimulate further analyses of interesting systems. For 779 KOIs with high enough SNRs, we derived the timing, duration and depth of 69,914 transits. For 1820 KOIs with lower SNR, we derived only the timing of 225,273 transits. After removal of outlier timings, we derived various statistics for each KOI that were used to indicate significant variations. Including systems found by previous works, we have detected 260 KOIs which showed significant TTVs with long-term variations (>100 day), and another fourteen KOIs with periodic modulations shorter than 100 day and small amplitudes. For five of those, the periodicity is probably due to the crossing of rotating stellar spots by the transiting planets.

  16. VizieR Online Data Catalog: Transit timing variations of 145 Kepler planets (Hadden+, 2017)

    Science.gov (United States)

    Hadden, S.; Lithwick, Y.

    2017-08-01

    We compute Markov chain Monte Carlo (MCMC) fits to the Transit Timing Variations (TTVs) of 55 Kepler multiplanet systems exhibiting significant TTVs, 33 of which do not have N-body TTV fits reported previously in the literature. In addition, our work provides a uniform treatment of TTV systems that have previously been analyzed elsewhere. (4 data files).

  17. Time and Space Issues in the Generation of Graph Transition Systems

    NARCIS (Netherlands)

    Rensink, Arend

    2005-01-01

    GROOVE is a tool for the automatic generation of graph transition systems from graph grammars. In this type of tool, both memory and time performance are of prime importance. In this paper we discuss the implementation techniques used for optimising the tool in this regard, and we list possible futu

  18. Scintigraphic determination of gastrointestinal transit times. A comparison with breath hydrogen and radiologic methods

    DEFF Research Database (Denmark)

    Madsen, J L; Larsen, N E; Hilsted, J

    1991-01-01

    A scintigraphic method for determination of gastrointestinal transit times was compared with the breath hydrogen test and a multiple-bolus, single-radiograph technique. A close temporal association was found between the caecal appearance of radioactivity and the onset of breath hydrogen excretion...... the breath hydrogen concentration profiles....

  19. Time evolution of chiral phase transition at finite temperature and density in the linear sigma model

    Energy Technology Data Exchange (ETDEWEB)

    Sato, K.; Koide, Tomoi; Maruyama, Masahiro [Tohoku Univ., Faculty of Science, Sendai, Miyagi (Japan)

    1999-08-01

    There are various approaches to nonequilibrium system. We use the projection operator method investigated by F. Shibata and N. Hashitsume on the linear sigma model at finite temperature and density. We derive a differential equation of the time evolution for the order parameter and pion number density in chiral phase transition. (author)

  20. Estimating changes in Stroke Volume by non-invasive pulse-oximetry Pulse Transit Time Measurements

    NARCIS (Netherlands)

    ten Bokkel-Andela, J.; Poterman, Marieke; Scheeren, Thomas; Kalmar, A.F.

    2015-01-01

    Background and Goal of Study:  Pulse wave transit time (PTT), the interval between the R-wave peak on an electrocardiogram (ECG) and arrival of the pulse waves in the periphery (e.g. the finger), is reported to be a reliable estimate for stroke volume[1,2]. In this study, the PTT based on ECG and th

  1. The Influence of Unpaid Work on the Transition out of Full-Time Paid Work

    Science.gov (United States)

    Carr, Dawn C.; Kail, Ben Lennox

    2013-01-01

    Purpose: Continued employment after retirement and engagement in unpaid work are both important ways of diminishing the negative economic effects of the retirement of baby boomer cohorts on society. Little research, however, examines the relationship between paid and unpaid work at the transition from full-time work. Using a resource perspective…

  2. Simultaneous Optimization of Container Ship Sailing Speed and Container Routing with Transit Time Restrictions

    DEFF Research Database (Denmark)

    Karsten, Christian Vad; Røpke, Stefan; Pisinger, David

    We introduce a decision support tool for liner shipping companies to optimally determine the sailing speed and needed fleet for a global network. As a novelty we incorporate cargo routing decisions with tight transit time restrictions on each container such that we get a realistic picture...

  3. Influence of orocaecal transit time on hydrogen excretion after carbohydrate malabsorption

    DEFF Research Database (Denmark)

    Rumessen, J J; Hamberg, O; Gudmand-Høyer, E

    1989-01-01

    The aim of the present study was to determine whether changes in orocaecal transit time (OCTT) affect the magnitude of the breath hydrogen (H2) excretion after ingestion of unabsorbable carbohydrate. We studied eight healthy subjects by interval sampling of end expiratory H2 concentration for 12...

  4. Effect of spike-timing-dependent plasticity on coherence resonance and synchronization transitions by time delay in adaptive neuronal networks

    Science.gov (United States)

    Xie, Huijuan; Gong, Yubing; Wang, Qi

    2016-06-01

    In this paper, we numerically study how time delay induces multiple coherence resonance (MCR) and synchronization transitions (ST) in adaptive Hodgkin-Huxley neuronal networks with spike-timing dependent plasticity (STDP). It is found that MCR induced by time delay STDP can be either enhanced or suppressed as the adjusting rate Ap of STDP changes, and ST by time delay varies with the increase of Ap, and there is optimal Ap by which the ST becomes strongest. It is also found that there are optimal network randomness and network size by which ST by time delay becomes strongest, and when Ap increases, the optimal network randomness and optimal network size increase and related ST is enhanced. These results show that STDP can either enhance or suppress MCR and optimal STDP can enhance ST induced by time delay in the adaptive neuronal networks. These findings provide a new insight into STDP's role for the information processing and transmission in neural systems.

  5. Combination of inulin and time dependent polymethacrylates as a coating system to achieve colonic delivery of indomethacin

    Directory of Open Access Journals (Sweden)

    A Akhgari

    2009-10-01

    Full Text Available "n "nBackground:In the previous study it was shown that films prepared from inulin (In in combination with Eudragit RS (ERS and RL (ERL were susceptible to inulinase. Purpose: The aim of this work was to assess the suitability of these combinations for colonic delivery of indomethacin. "nMethods: Indomethacin was loaded onto non-pareil seeds using fluidized bed apparatus to produce pellets with 20% w/w drug load. Drug loaded pellets were coated with In-ERS in the ratios of 20:80 and 30:70, or In-ERL in the ratio of 20:80 to different coating loads. The release of drug was examined in simulated gastric (for 2 hrs and small intestine and in the presence of inulinase in simulated colonic medium (for 12 or 24 hrs. "nResults: The results of this study revealed that incorporation of inulin as a bacterially degradable polysaccharide into ERS or ERL could modulate drug release. Coating level up to 15% significantly affected drug release from In-ERL or In-ERS coated pellets. However further increase in coating load to 20% had no significant effect on drug release from In-ERL coated pellets (f1=9.39. Drug release from In-ERL coated pellets was faster and showed some pH dependency. "nConclusions: Formulation coated with In-ERS (20:80 and coating level of 20% was considered more appropriate for colon delivery of indomethacin, as drug release was pH independent and formulation was resistant to drug release in the upper GI media for up to 7 hrs. This formulation was also susceptible to inulinase and released about 40% of indomethacin in the simulated colonic media.

  6. Bunching transition in a time-headway model of a bus route.

    Science.gov (United States)

    Nagatani, T

    2001-03-01

    A time-headway model is presented to mimic bus behavior on the bus route. The motion of a bus is described in terms of the time headway between its bus and the bus in front. We study the bunching behavior of buses induced by interacting with other buses and passengers. It is shown that the dynamical phase transitions among the inhomogeneous bunching phase, the homogeneous free phase, the coexisting phase, and the homogeneous congested phase occur with varying the initial time headway. We study the effect of not stopping at bus stops on the time-headway profile. It is found that the bunching transition lines are consistent with the neutral stability curves obtained by the linear stability analysis.

  7. Synchronization transitions in coupled time-delay electronic circuits with a threshold nonlinearity.

    Science.gov (United States)

    Srinivasan, K; Senthilkumar, D V; Murali, K; Lakshmanan, M; Kurths, J

    2011-06-01

    Experimental observations of typical kinds of synchronization transitions are reported in unidirectionally coupled time-delay electronic circuits with a threshold nonlinearity and two time delays, namely feedback delay τ(1) and coupling delay τ(2). We have observed transitions from anticipatory to lag via complete synchronization and their inverse counterparts with excitatory and inhibitory couplings, respectively, as a function of the coupling delay τ(2). The anticipating and lag times depend on the difference between the feedback and the coupling delays. A single stability condition for all the different types of synchronization is found to be valid as the stability condition is independent of both the delays. Further, the existence of different kinds of synchronizations observed experimentally is corroborated by numerical simulations and from the changes in the Lyapunov exponents of the coupled time-delay systems.

  8. The barrier method: a technique for calculating very long transition times.

    Science.gov (United States)

    Adams, D A; Sander, L M; Ziff, R M

    2010-09-28

    In many dynamical systems, there is a large separation of time scales between typical events and "rare" events which can be the cases of interest. Rare-event rates are quite difficult to compute numerically, but they are of considerable practical importance in many fields, for example, transition times in chemical physics and extinction times in epidemiology can be very long, but are quite important. We present a very fast numerical technique that can be used to find long transition times (very small rates) in low-dimensional systems, even if they lack detailed balance. We illustrate the method for a bistable nonequilibrium system introduced by Maier and Stein and a two-dimensional (in parameter space) epidemiology model.

  9. Virtual single-photon transition interrupted: time-gated optical gain and loss

    CERN Document Server

    Herrmann, Jens; Locher, Reto; Sabbar, Mazyar; Rivière, Paula; Saalmann, Ulf; Rost, Jan-Michael; Gallmann, Lukas; Keller, Ursula

    2012-01-01

    The optical response of a virtual dipole transition triggered by an ultra-short light pulse intrinsically consists of both absorption and emission in time and frequency. So far, this fundamental feature has been hidden by the time-integrated detection. However, as we will demonstrate, the time-dependence during a virtual single-photon transition can be mapped out and controlled by a second electromagnetic field. The resulting time-gated optical signal shows previously unexpected radiation gain and loss at different delays of the control pulse. The model presented here can be applied to any system that assumes a two-level character through near-resonant optical dipole excitation, whether they are of atomic, molecular or even solid-state nature. We validate the theoretical model by an attosecond transient absorption spectroscopy experiment in helium. Our model and the experimental data display excellent qualitative agreement.

  10. The Diversity of Low-mass Exoplanets Characterized via Transit Timing

    Science.gov (United States)

    Jontof-Hutter, Daniel; Ford, Eric B.; Rowe, Jason F.; Lissauer, Jack. J.; Fabrycky, Daniel C.

    2016-10-01

    Transit timing variations (TTV) in multi-transiting systems enables precise characterizations of low-mass planets and their orbits. The range of orbital periods and incident fluxes with detailed TTV constraints complements the radial velocity sample for low-mass planets, pushing exoplanet characterization to the regime sub-Earth size planets and out to Mercury-like distances. This has revealed an astonishing diversity in the density of super-Earth mass planets. We summarize these and other contributions to exoplanet science from TTVs.

  11. Real-time study of graphene's phase transition in polymer matrices.

    Science.gov (United States)

    Li, Qiang; Li, Zhongjun; Chen, Moran; Fang, Ying

    2009-05-01

    We present real-time study of pristine graphene sandwiched in a homogeneous polymer matrix and its phase transition where the graphene membrane irreversibly scrolls and folds above the polymer's glass temperature. Tubular structures tend to form by curling up from edge defects of graphene and roll along its surface. A single-layer can also fold into two- or three-layer stacks and the overlapping between layers extends along the membrane surface to enlarge up to micrometer sizes. Further, oxidized graphene does not show such reactivity at even higher temperatures, indicating that the intrinsic thermal instability of pristine graphene in the polymer matrix is the origin of the transition.

  12. Time-dependent renormalized Redfield theory II for off-diagonal transition in reduced density matrix

    Science.gov (United States)

    Kimura, Akihiro

    2016-09-01

    In our previous letter (Kimura, 2016), we constructed time-dependent renormalized Redfield theory (TRRT) only for diagonal transition in a reduced density matrix. In this letter, we formulate the general expression for off-diagonal transition in the reduced density matrix. We discuss the applicability of TRRT by numerically comparing the dependencies on the energy gap of the exciton relaxation rate by using the TRRT and the modified Redfield theory (MRT). In particular, we roughly show that TRRT improves MRT for the detailed balance about the excitation energy transfer reaction.

  13. Late time cosmological phase transitions 1: Particle physics models and cosmic evolution

    Science.gov (United States)

    Frieman, Joshua A.; Hill, Christopher T.; Watkins, Richard

    1991-01-01

    We described a natural particle physics basis for late-time phase transitions in the universe. Such a transition can seed the formation of large-scale structure while leaving a minimal imprint upon the microwave background anisotropy. The key ingredient is an ultra-light pseudo-Nambu-Goldstone boson with an astronomically large (O(kpc-Mpc)) Compton wavelength. We analyze the cosmological signatures of and constraints upon a wide class of scenarios which do not involve domain walls. In addition to seeding structure, coherent ultra-light bosons may also provide unclustered dark matter in a spatially flat universe, omega sub phi approx. = 1.

  14. Linear and nonlinear theory of the proton beam transit-time oscillator (TTO)

    Science.gov (United States)

    Walsh, John E.; Mostrom, Michael A.; Clark, Randy M.; Arman, M. Joseph; Campbell, Mark M.

    1989-07-01

    A theoretical characterization is presented for both the small- and large-amplitude behaviors of the intense beam-driven transit-time oscillator device which encompasses the effects of the beam self-fields and space-charge effects. The theory has been employed in the development of expressions for comparison with particle simulation results. Attention is given to the effect of beam-plasma frequency on gain, saturation growth in the monotron, the effects of space-charge depression on the transit angle, and the dependence of monotron performance on beam energy.

  15. Amplification of Quantum Meson Modes in the Late Time of the Chiral Phase Transition

    CERN Document Server

    Watanabe, K

    2007-01-01

    We investigate the time evolution of the quantum meson modes in the late time of chiral phase transition. In particular, it is shown that there exists a possible solution to the equation of motion for the quantum meson modes, which reveals a parametric resonance and/or resonance through forced oscillation induced by the small oscillation of the chiral condensate. After that, we demonstrate the unstable regions for the quantum meson modes in both the cases of a uniform and spatially expanding system.

  16. Nanosecond-scale timing jitter in transition edge sensors at telecom and visible wavelengths

    CERN Document Server

    Lamas-Linares, Antia; Tomlin, Nathan A; Gerrits, Thomas; Lita, Adriana E; Beyer, Joern; Mirin, Richard P; Nam, Sae Woo

    2013-01-01

    Transition edge sensors (TES) have the highest reported efficiencies (>98%) for detection of single photons in the visible and near infrared. Experiments in quantum information and foundations of physics that rely critically on this efficiency have started incorporating these detectors into con- ventional quantum optics setups. However, their range of applicability has been hindered by slow operation both in recovery time and timing jitter. We show here how a conventional tungsten-TES can be operated with jitter times of < 4 ns, well within the timing resolution necessary for MHz clocking of experiments, and providing an important practical simplification for experiments that rely on the simultaneous closing of both efficiency and locality loopholes.

  17. Transit Timing Variation analysis with Kepler light curves of KOI 227 and Kepler 93b

    Science.gov (United States)

    Dulz, Shannon; Reed, Mike

    2017-01-01

    By searching for transit signals in approximately 150,000 stars, NASA’s Kepler Space telescope found thousands of exoplanets over its primary mission from 2009 to 2013 (Tenenbaum et al. 2014, ApJS, 211, 6). Yet, a detailed follow-up examination of Kepler light curves may contribute more evidence on system dynamics and planetary atmospheres of these objects. Kepler’s continuous observing of these systems over the mission duration produced light curves of sufficient duration to allow for the search for transit timing variations. Transit timing variations over the course of many orbits may indicate a precessing orbit or the existence of a non-transiting third body such as another exoplanet. Flux contributions of the planet just prior to secondary eclipse may provide a measurement of bond albedo from the day-side of the transiting planet. Any asymmetries of the transit shape may indicate thermal asymmetries which can measure upper atmosphere motion of the planet. These two factors can constrain atmospheric models of close orbiting exoplanets. We first establish our procedure with the well-documented TTV system, KOI 227 (Nesvorny et al. 2014, ApJ, 790, 31). Using the test case of KOI 227, we analyze Kepler-93b for TTVs and day-side flux contributions. Kepler-93b is likely a rocky planet with R = 1.50 ± 0.03 Earth Radii and M = 2.59 ± 2.0 Earth Masses (Marcy et al. 2014, ApJS, 210, 20). This research is funded by a NASA EPSCoR grant.

  18. Universal space-time scaling symmetry in the dynamics of bosons across a quantum phase transition

    CERN Document Server

    Clark, Logan W; Chin, Cheng

    2016-01-01

    The dynamics of many-body systems spanning condensed matter, cosmology, and beyond is hypothesized to be universal when the systems cross continuous phase transitions. The universal dynamics is expected to satisfy a scaling symmetry of space and time with the crossing rate, inspired by the Kibble-Zurek mechanism. We test this symmetry based on Bose condensates in a shaken optical lattice. Shaking the lattice drives condensates across an effectively ferromagnetic quantum phase transition. After crossing the critical point, the condensates manifest delayed growth of spin fluctuations and develop anti-ferromagnetic spatial correlations resulting from sub-Poisson generation of topological defects. The characteristic times and lengths scale as power-laws of the crossing rate, yielding the temporal exponent 0.50(2) and the spatial exponent 0.26(2), consistent with theory. Furthermore, the fluctuations and correlations are invariant in scaled space-time coordinates, in support of the scaling symmetry of quantum crit...

  19. Mean transit time image - a new method of analyzing brain perfusion studies

    Energy Technology Data Exchange (ETDEWEB)

    Szabo, Z.; Ritzl, F.

    1983-05-01

    Point-by-point calculation of the mean transit time based on gamma fit was used to analyze brain perfusion studies in a vertex view. The algorithm and preliminary results in normal brain and in different stages of cerebral perfusion abnormality (ischemia, stroke, migraine, tumor, abscess) are demonstrated. In contrast to the traditional methods using fixed, a priori defined regions of interest this type of mapping of the relative regions cerebral perfusion shows more clearly the irregular outlines of the disturbance. Right to left activity ratios in the arterial part of the time-activity curves showed significant correlation with the mean transit time ratios (Q/sub 1/=1.185-0.192 Qsub(a), n=38, r=0.716, P<0.001).

  20. Autaptic self-feedback-induced synchronization transitions in Newman-Watts neuronal network with time delays

    Science.gov (United States)

    Wang, Qi; Gong, Yubing; Wu, Yanan

    2015-04-01

    Autapse is a special synapse that connects a neuron to itself. In this work, we numerically study the effect of chemical autapse on the synchronization of Newman-Watts Hodgkin-Huxley neuron network with time delays. It is found that the neurons exhibit synchronization transitions as autaptic self-feedback delay is varied, and the phenomenon enhances when autaptic self-feedback strength increases. Moreover, this phenomenon becomes strongest when network time delay or coupling strength is optimal. It is also found that the synchronization transitions by network time delay can be enhanced by autaptic activity and become strongest when autaptic delay is optimal. These results show that autaptic delayed self-feedback activity can intermittently enhance and reduce the synchronization of the neuronal network and hence plays an important role in regulating the synchronization of the neurons. These findings could find potential implications for the information processing and transmission in neural systems.

  1. Classical and relativistic long-term time variations of some observables for transiting exoplanets

    CERN Document Server

    Iorio, Lorenzo

    2010-01-01

    We analytically work out the long-term, i.e. averaged over one orbital revolution, time variations of some direct observable quantities Y induced by classical and general relativistic dynamical perturbations of the two-body pointlike Newtonian acceleration in the case of transiting exoplanets moving along elliptic orbits. More specifically, the observables $Y$ with which we deal are the transit duration, the radial velocity and the time interval between primary and secondary eclipses. The dynamical effects considered are the centrifugal oblateness of both the star and the planet, their tidal bulges mutually raised on each other, a distant third body X, and general relativity (both Schwarzschild and Lense-Thirring). We take into account the effects due to the perturbations of all the Keplerian orbital elements involved in a consistent and uniform way. First, we explicitly compute their instantaneous time variations due to the dynamical effects considered and plug them in the general expression for the instanta...

  2. The Weibull - log Weibull transition of interoccurrence times for synthetic and natural earthquakes

    CERN Document Server

    Hasumi, Tomohiro; Akimoto, Takuma; Aizawa, Yoji

    2008-01-01

    We have studied interoccurrence time distributions by analyzing the synthetic and three natural catalogs of the Japan Meteorological Agency (JMA), the Southern California Earthquake Data Center (SCEDC), and Taiwan Central Weather Bureau (TCWB) and revealed the universal feature of the interoccurrence time statistics, Weibull - log Weibull transition. This transition reinforces the view that the interoccurrence time statistics possess Weibull statistics and log-Weibull statistics. Here in this paper, the crossover magnitude from the superposition regime to the Weibull regime $m_c^2$ is proportional to the plate velocity. In addition, we have found the region-independent relation, $m_c^2/m_{max} = 0.54 \\pm 0.004$.

  3. Bayesian Nonparametric Estimation for Dynamic Treatment Regimes with Sequential Transition Times.

    Science.gov (United States)

    Xu, Yanxun; Müller, Peter; Wahed, Abdus S; Thall, Peter F

    2016-01-01

    We analyze a dataset arising from a clinical trial involving multi-stage chemotherapy regimes for acute leukemia. The trial design was a 2 × 2 factorial for frontline therapies only. Motivated by the idea that subsequent salvage treatments affect survival time, we model therapy as a dynamic treatment regime (DTR), that is, an alternating sequence of adaptive treatments or other actions and transition times between disease states. These sequences may vary substantially between patients, depending on how the regime plays out. To evaluate the regimes, mean overall survival time is expressed as a weighted average of the means of all possible sums of successive transitions times. We assume a Bayesian nonparametric survival regression model for each transition time, with a dependent Dirichlet process prior and Gaussian process base measure (DDP-GP). Posterior simulation is implemented by Markov chain Monte Carlo (MCMC) sampling. We provide general guidelines for constructing a prior using empirical Bayes methods. The proposed approach is compared with inverse probability of treatment weighting, including a doubly robust augmented version of this approach, for both single-stage and multi-stage regimes with treatment assignment depending on baseline covariates. The simulations show that the proposed nonparametric Bayesian approach can substantially improve inference compared to existing methods. An R program for implementing the DDP-GP-based Bayesian nonparametric analysis is freely available at https://www.ma.utexas.edu/users/yxu/.

  4. Observer-based robust finite time H∞ sliding mode control for Markovian switching systems with mode-dependent time-varying delay and incomplete transition rate.

    Science.gov (United States)

    Gao, Lijun; Jiang, Xiaoxiao; Wang, Dandan

    2016-03-01

    This paper investigates the problem of robust finite time H∞ sliding mode control for a class of Markovian switching systems. The system is subjected to the mode-dependent time-varying delay, partly unknown transition rate and unmeasurable state. The main difficulty is that, a sliding mode surface cannot be designed based on the unknown transition rate and unmeasurable state directly. To overcome this obstacle, the set of modes is firstly divided into two subsets standing for known transition rate subset and unknown one, based on which a state observer is established. A component robust finite-time sliding mode controller is also designed to cope with the effect of partially unknown transition rate. It is illustrated that the reachability, finite-time stability, finite-time boundedness, finite-time H∞ state feedback stabilization of sliding mode dynamics can be ensured despite the unknown transition rate. Finally, the simulation results verify the effectiveness of robust finite time control problem.

  5. New Parameters and Transit Timing Studies for OGLE2-TR-L9 b

    CERN Document Server

    Lendl, M; Koppenhoefer, J; Nikolov, N; Henning, Th; Swain, M; Greiner, J

    2010-01-01

    Context: Repeated observations of exoplanet transits allow us to refine the planetary parameters and probe them for any time dependent variations. In particular deviations of the period from a strictly linear ephemeris, transit timing variations (TTVs), can indicate the presence of additional bodies in the planetary system. Aims: Our goal was to reexamine the largely unstudied OGLE2-TR-L9 system with high cadence, multi-color photometry in order to refine the planetary parameters and probe the system for TTVs. Methods: We observed five full transits of OGLE2-TR-L9 with the GROND instrument at the ESO/MPG 2.2 m telescope at La Silla Observatory. GROND is a multichannel imager that allowed us to gather simultaneous light curves in the g', r', i', and z' filters. Results: From our analysis we find that the semi-major axis and the inclination differ from the previously published values. With the newly observed transits, we were able to refine the ephemeris to 2454492.80008(+/- 0.00014) + 2.48553417(+/- 6.4) x 10^...

  6. Observation of parity-time symmetry breaking transitions in a dissipative Floquet system of ultracold atoms

    CERN Document Server

    Li, Jiaming; Liu, Ji; de Melo, Leonardo; Joglekar, Yogesh N; Luo, Le

    2016-01-01

    Open physical systems with balanced loss and gain exhibit a transition, absent in their solitary counterparts, which engenders modes that exponentially decay or grow with time and thus spontaneously breaks the parity-time PT symmetry. This PT-symmetry breaking is induced by modulating the strength or the temporal profile of the loss and gain, but also occurs in a pure dissipative system without gain. It has been observed that, in classical systems with mechanical, electrical, and electromagnetic setups with static loss and gain, the PT-symmetry breaking transition leads to extraordinary behavior and functionalities. However, its observation in a quantum system is yet to be realized. Here we report on the first quantum simulation of PT-symmetry breaking transitions using ultracold Li-6 atoms. We simulate static and Floquet dissipative Hamiltonians by generating state-dependent atom loss in a noninteracting Fermi gas, and observe the PT-symmetry breaking transitions by tracking the atom number for each state. W...

  7. The mass of the Mars-sized exoplanet Kepler-138 b from transit timing.

    Science.gov (United States)

    Jontof-Hutter, Daniel; Rowe, Jason F; Lissauer, Jack J; Fabrycky, Daniel C; Ford, Eric B

    2015-06-18

    Extrasolar planets that pass in front of their host star (transit) cause a temporary decrease in the apparent brightness of the star, providing a direct measure of the planet's size and orbital period. In some systems with multiple transiting planets, the times of the transits are measurably affected by the gravitational interactions between neighbouring planets. In favourable cases, the departures from Keplerian orbits (that is, unaffected by gravitational effects) implied by the observed transit times permit the planetary masses to be measured, which is key to determining their bulk densities. Characterizing rocky planets is particularly difficult, because they are generally smaller and less massive than gaseous planets. Therefore, few exoplanets near the size of Earth have had their masses measured. Here we report the sizes and masses of three planets orbiting Kepler-138, a star much fainter and cooler than the Sun. We determine that the mass of the Mars-sized inner planet, Kepler-138 b, is 0.066(+0.059)(-0.037) Earth masses. Its density is 2.6(+2.4)(-1.5) grams per cubic centimetre. The middle and outer planets are both slightly larger than Earth. The middle planet's density (6.2(+5.8)(-3.4) grams per cubic centimetre) is similar to that of Earth, and the outer planet is less than half as dense at 2.1(+2.2)(-1.2) grams per cubic centimetre, implying that it contains a greater portion of low-density components such as water and hydrogen.

  8. Pathogenesis of tropical sprue: A pilot study of antroduodenal manometry, duodenocaecal transit time & fat-induced ileal brake

    Directory of Open Access Journals (Sweden)

    Uday C Ghoshal

    2013-01-01

    Full Text Available Background & objectives: Small intestinal bacterial overgrowth (SIBO due to ileal brake-induced hypomotility may cause tropical sprue (TS. We evaluated effect of infusion of fat or placebo in duodenum randomly in patients with TS and healthy controls on antroduodenal manometry (ADM and mediators of ileal brake, and duodenocaecal transit time (DCTT. Methods: ADM and DCTT (lactulose hydrogen breath test, HBT were evaluated with placebo and fat in eight controls and 13 patients with TS (diagnostic criteria: tests showing malabsorption of two unrelated substances, abnormal duodenal histology, absence of other causes, response to antibiotics and folate. Results: Patients with TS (6 had SIBO by glucose HBT were similar in age and gender with controls. After fat infusion, proximal gut motility index (MI was reduced compared to fasting state in TS, and DCTT was longer in TS than controls (200 min, 120-380 vs. 130, 70-160, P=0.001, though comparable after placebo (70 min, 30-140 vs. 60, 40-90. TS patients had higher PYY and neurotensin than controls after fat infusion. DCTT after fat infusion correlated with plasma level of PYY in TS but not in controls. Post-fat PYY and neurotensin levels were higher in TS with lower BMI (<16 kg/m [2] than those with higher BMI. Parameters of ileal brake (post-fat DCTT, PYY and neurotensin were higher in patients with than without SIBO. Interpretation & conclusions: Fat infusion reduced proximal gut MI, increased DCTT, PYY, and neurotensin among patients with TS. Malabsorbed fat might cause exaggerated ileal brake reducing gut motility, promoting SIBO and bacterial colonization and malabsorption in TS.

  9. Fluctuation of similarity to detect transitions between distinct dynamical regimes in short time series.

    Science.gov (United States)

    Malik, Nishant; Marwan, Norbert; Zou, Yong; Mucha, Peter J; Kurths, Jürgen

    2014-06-01

    A method to identify distinct dynamical regimes and transitions between those regimes in a short univariate time series was recently introduced [N. Malik et al., Europhys. Lett. 97, 40009 (2012)], employing the computation of fluctuations in a measure of nonlinear similarity based on local recurrence properties. In this work, we describe the details of the analytical relationships between this newly introduced measure and the well-known concepts of attractor dimensions and Lyapunov exponents. We show that the new measure has linear dependence on the effective dimension of the attractor and it measures the variations in the sum of the Lyapunov spectrum. To illustrate the practical usefulness of the method, we identify various types of dynamical transitions in different nonlinear models. We present testbed examples for the new method's robustness against noise and missing values in the time series. We also use this method to analyze time series of social dynamics, specifically an analysis of the US crime record time series from 1975 to 1993. Using this method, we find that dynamical complexity in robberies was influenced by the unemployment rate until the late 1980s. We have also observed a dynamical transition in homicide and robbery rates in the late 1980s and early 1990s, leading to increase in the dynamical complexity of these rates.

  10. Transit Timing Observations from Kepler: IV. Confirmation of 4 Multiple Planet Systems by Simple Physical Models

    Energy Technology Data Exchange (ETDEWEB)

    Fabrycky, Daniel C.; /UC, Santa Cruz; Ford, Eric B.; /Florida U.; Steffen, Jason H.; /Fermilab; Rowe, Jason F.; /SETI Inst., Mtn. View /NASA, Ames; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Moorhead, Althea V.; /Florida U.; Batalha, Natalie M.; /San Jose State U.; Borucki, William J.; /NASA, Ames; Bryson, Steve; /NASA, Ames; Buchhave, Lars A.; /Bohr Inst. /Copenhagen U.; Christiansen, Jessie L.; /SETI Inst., Mtn. View /NASA, Ames /Caltech

    2012-01-01

    Eighty planetary systems of two or more planets are known to orbit stars other than the Sun. For most, the data can be sufficiently explained by non-interacting Keplerian orbits, so the dynamical interactions of these systems have not been observed. Here we present 4 sets of lightcurves from the Kepler spacecraft, which each show multiple planets transiting the same star. Departure of the timing of these transits from strict periodicity indicates the planets are perturbing each other: the observed timing variations match the forcing frequency of the other planet. This confirms that these objects are in the same system. Next we limit their masses to the planetary regime by requiring the system remain stable for astronomical timescales. Finally, we report dynamical fits to the transit times, yielding possible values for the planets masses and eccentricities. As the timespan of timing data increases, dynamical fits may allow detailed constraints on the systems architectures, even in cases for which high-precision Doppler follow-up is impractical.

  11. Wavelength dependent measurements of optical fiber transit time, material dispersion, and attenuation

    Energy Technology Data Exchange (ETDEWEB)

    COCHRANE,KYLE ROBERT; BAILEY,JAMES E.; LAKE,PATRICK WAYNE; CARLSON,ALAN L.

    2000-04-18

    A new method for measuring the wavelength dependence of the transit time, material dispersion, and attenuation of an optical fiber is described. The authors inject light from a 4-ns risetime pulsed broad-band flashlamp into various length fibers and record the transmitted signals with a time-resolved spectrograph. Segments of data spanning an approximately 3,000 {angstrom} range are recorded from a single flashlamp pulse. Comparison of data acquired with short and long fibers enables the determination of the transit time and the material dispersion as functions of wavelength dependence for the entire recorded spectrum simultaneously. The wavelength dependent attenuation is also determined from the signal intensities. The method is demonstrated with experiments using a step index 200-{micro}m-diameter SiO{sub 2} fiber. The results agree with the transit time determined from the bulk glass refractive index to within {+-} 0.035% for the visible (4,000--7,200 {angstrom}) spectrum and 0.12% for the ultraviolet (2,650--4,000 {angstrom}) spectrum, and with the attenuation specified by the fiber manufacturer to within {+-} 10%.

  12. Transition from phase to generalized synchronization in time-delay systems.

    Science.gov (United States)

    Senthilkumar, D V; Lakshmanan, M; Kurths, J

    2008-06-01

    The notion of phase synchronization in time-delay systems, exhibiting highly non-phase-coherent attractors, has not been realized yet even though it has been well studied in chaotic dynamical systems without delay. We report the identification of phase synchronization in coupled nonidentical piecewise linear and in coupled Mackey-Glass time-delay systems with highly non-phase-coherent regimes. We show that there is a transition from nonsynchronized behavior to phase and then to generalized synchronization as a function of coupling strength. We have introduced a transformation to capture the phase of the non-phase-coherent attractors, which works equally well for both the time-delay systems. The instantaneous phases of the above coupled systems calculated from the transformed attractors satisfy both the phase and mean frequency locking conditions. These transitions are also characterized in terms of recurrence-based indices, namely generalized autocorrelation function P(t), correlation of probability of recurrence, joint probability of recurrence, and similarity of probability of recurrence. We have quantified the different synchronization regimes in terms of these indices. The existence of phase synchronization is also characterized by typical transitions in the Lyapunov exponents of the coupled time-delay systems.

  13. Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors - Particle Detectors and Detector Systems

    CERN Document Server

    Ullaland, O

    2011-01-01

    Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors in 'Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Section '3.3 Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.3 Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors 3.3.1 Introduction 3.3.2 Time of Flight Measurements 3.3.2.1 Scintillator hodoscopes 3.3.2.2 Parallel plate ToF detectors 3.3.3 Cherenkov Radiation 3.3.3.1 ...

  14. Distribution of capillary transit times in isolated lungs of oxygen-tolerant rats.

    Science.gov (United States)

    Ramakrishna, Madhavi; Gan, Zhuohui; Clough, Anne V; Molthen, Robert C; Roerig, David L; Audi, Said H

    2010-11-01

    Rats pre-exposed to 85% O₂ for 5-7 days tolerate the otherwise lethal effects of 100% O₂. The objective was to evaluate the effect of rat exposure to 85% O₂ for 7 days on lung capillary mean transit time t(c) and distribution of capillary transit times (h(c)(t)). This information is important for subsequent evaluation of the effect of this hyperoxia model on the redox metabolic functions of the pulmonary capillary endothelium. The venous concentration vs. time outflow curves of fluorescein isothiocyanate labeled dextran (FITC-dex), an intravascular indicator, and coenzyme Q₁ hydroquinone (CoQ₁H₂), a compound which rapidly equilibrates between blood and tissue on passage through the pulmonary circulation, were measured following their bolus injection into the pulmonary artery of isolated perfused lungs from rats exposed to room air (normoxic) or 85% O₂ for 7 days (hyperoxic). The moments (mean transit time and variance) of the measured FITC-dex and CoQ₁H₂ outflow curves were determined for each lung, and were then used in a mathematical model [Audi et al. J. Appl. Physiol. 77: 332-351, 1994] to estimate t(c) and the relative dispersion (RD(c)) of h (c)(t). Data analysis reveals that exposure to hyperoxia decreases lung t(c) by 42% and increases RD(c), a measure h(c)(t) heterogeneity, by 40%.

  15. Bayesian optimization of perfusion and transit time estimation in PASL-MRI.

    Science.gov (United States)

    Santos, Nuno; Sanches, João; Figueiredo, Patrícia

    2010-01-01

    Pulsed Arterial Spin Labeling (PASL) techniques potentially allow the absolute, non-invasive quantification of brain perfusion and arterial transit time. This can be achieved by fitting a kinetic model to the data acquired at a number of inversion time points (TI). The intrinsically low SNR of PASL data, together with the uncertainty in the model parameters, can hinder the estimation of the parameters of interest. Here, a two-compartment kinetic model is used to estimate perfusion and transit time, based on a Maximum a Posteriori (MAP) criterion. A priori information concerning the physiological variation of the multiple model parameters is used to guide the solution. Monte Carlo simulations are performed to compare the accuracy of our proposed Bayesian estimation method with a conventional Least Squares (LS) approach, using four different sets of TI points. Each set is obtained either with a uniform distribution or an optimal sampling strategy designed based on the same MAP criterion. We show that the estimation errors are minimized when our proposed Bayesian estimation method is employed in combination with an optimal set of sampling points. In conclusion, our results indicate that PASL perfusion and transit time measurements would benefit from a Bayesian approach for the optimization of both the sampling strategy and the estimation algorithm, whereby prior information on the parameters is used.

  16. Colonic Lipomas Mimicking Colon Cancer

    Directory of Open Access Journals (Sweden)

    Berna AYTAÇ

    2010-09-01

    Full Text Available Objective: Colonic lipomas are uncommon tumors of the gastrointestinal tract. Most of these tumors are asymptomatic and usually detected incidentally during colonoscopy or laparotomy and do not require treatment. Large lipomas are usually symptomatic and may mimic clinic manifestations of colonic carcinoma. Here we studied seven cases of submucosal and intramuscular colonic lipomas to evaluate the clinical features, diagnosis and treatment of this disease.Material and Method: Seven patients who were diagnosed with colonic lipoma between 1999 and 2006 were evaluated as regards age, gender, size of tumor, anatomic site, symptoms, location and treatment modality.Result: The mean age was 57.8± 14.7 years. Five patients were male and two were female. The size of the lipomas ranged from 1 to 5.5 cm and all were symptomatic except one patient. Five of the gastrointestinal lipomas were located submucosally and 2 intramurally. Five lipomas arose from the ascending colon, 1 from the hepatic flexure and 1 from the splenic flexure. Four large GI lipomas were removed by subtotal resection and one case underwent hemicolectomy while two pedunculated lipomas were resected by polypectomy. No recurrence was found after at least one year follow-up with endoscopic examination.Conclusion: Colonic lipomas may mimic malignancy with their clinical manifestations. Appropriate radiological and colonoscopic evaluation is essential to avoid unnecessary wide resections.

  17. Speculation on the timing and nature of Late Pleistocene hunter-gatherer colonization of the Tibetan Plateau

    Institute of Scientific and Technical Information of China (English)

    P. J. Brantingham; MA Haizhou; J. W. Olsen; GAO Xing; D. B. Madsen; D. E. Rhode

    2003-01-01

    Hunter-gatherer populations in greater northeast Asia experienced dramatic range expansions during the early Upper Paleolithic (45-22 ka) and the late Upper Paleolithic (18-10 ka), both of which led to intensive occupations of cold desert environments including the Mongolian Gobi and northwest China. Range contractions under the cold, arid extremes of the Last Glacial Maximum (LGM, 22-18 ka) may have entailed widespread population extirpations. The high elevation Qinghai-Tibetan Plateau is significantly more extreme in both climate and environment than either the Gobi or the Siberian taiga forests, and provides an ideal setting to test fundamental models of human biogeog-raphy in the context of regional population fluctuations. The area is presently occupied primarily by nomadic pastoralists, but it is clear that these complex middle Holocene (<6 ka) economic adaptations were not a necessary prerequisite for successful colonization of the high elevation Plateau. Exploratory field-work in 2000-2001 has established that Upper Paleolithic hunter-gatherers were present on the Qinghai-Tibetan Plateau by at least 12 ka and possibly much earlier. Aspeculative model for the colonization process is developed and preliminary archaeological data in support of the model are presented.

  18. Electrochemical fecal pellet sensor for simultaneous real-time ex vivo detection of colonic serotonin signalling and motility

    Science.gov (United States)

    Morris, Rachel; Fagan-Murphy, Aidan; MacEachern, Sarah J.; Covill, Derek; Patel, Bhavik Anil

    2016-03-01

    Various investigations have focused on understanding the relationship between mucosal serotonin (5-HT) and colonic motility, however contradictory studies have questioned the importance of this intestinal transmitter. Here we described the fabrication and use of a fecal pellet electrochemical sensor that can be used to simultaneously detect the release of luminal 5-HT and colonic motility. Fecal pellet sensor devices were fabricated using carbon nanotube composite electrodes that were housed in 3D printed components in order to generate a device that had shape and size that mimicked a natural fecal pellet. Devices were fabricated where varying regions of the pellet contained the electrode. Devices showed that they were stable and sensitive for ex vivo detection of 5-HT, and no differences in the fecal pellet velocity was observed when compared to natural fecal pellets. The onset of mucosal 5-HT was observed prior to the movement of the fecal pellet. The release of mucosal 5-HT occurred oral to the fecal pellet and was linked to the contraction of the bowel wall that drove pellet propulsion. Taken, together these findings provide new insights into the role of mucosal 5-HT and suggest that the transmitter acts as a key initiator of fecal pellet propulsion.

  19. Pulmonary blood volume and transit time in cirrhosis: relation to lung function

    DEFF Research Database (Denmark)

    Møller, Søren; Burchardt, H; Øgard, CG;

    2006-01-01

    not been determined separately we assessed PBV and pulmonary transit time (PTT) in relation to lung function in patients with cirrhosis and in controls. METHODS: Pulmonary and cardiac haemodynamics and transit times were determined by radionuclide techniques in 22 patients with alcoholic cirrhosis......BACKGROUND/AIMS: In cirrhosis a systemic vasodilatation leads to an abnormal distribution of the blood volume with a contracted central blood volume. In addition, the patients have a ventilation/perfusion imbalance with a low diffusing capacity. As the size of the pulmonary blood volume (PBV) has...... and in 12 controls. The lung function including diffusing capacity for carbon monoxide (DL, CO) was determined by conventional single breath technique. RESULTS: In the patients, PTT was shorter, 3.9+/-1.2 vs 5.7+/-1.0 s in the controls, P

  20. Pulmonary blood volume and transit time in cirrhosis: relation to lung function

    DEFF Research Database (Denmark)

    Møller, Søren; Burchardt, H; Øgard, CG

    2006-01-01

    BACKGROUND/AIMS: In cirrhosis a systemic vasodilatation leads to an abnormal distribution of the blood volume with a contracted central blood volume. In addition, the patients have a ventilation/perfusion imbalance with a low diffusing capacity. As the size of the pulmonary blood volume (PBV) has...... not been determined separately we assessed PBV and pulmonary transit time (PTT) in relation to lung function in patients with cirrhosis and in controls. METHODS: Pulmonary and cardiac haemodynamics and transit times were determined by radionuclide techniques in 22 patients with alcoholic cirrhosis...... and in 12 controls. The lung function including diffusing capacity for carbon monoxide (DL, CO) was determined by conventional single breath technique. RESULTS: In the patients, PTT was shorter, 3.9+/-1.2 vs 5.7+/-1.0 s in the controls, P

  1. Design of cavity-enhanced absorption cell for reducing transit-time broadening.

    Science.gov (United States)

    Abe, Masashi; Iwakuni, Kana; Okubo, Sho; Sasada, Hiroyuki

    2014-09-15

    To reduce the linewidth of Lamb dips, we introduce a cavity-enhanced absorption cell (CEAC) coupled with a Gaussian beam with a 1.9-mm 1/e(2) radius at the beam waist for the reduction of transit-time broadening. We state that transit-time broadening depends only on the beam radius at the beam waist. This fact is useful for the design of the CEAC, and a pair of concave and convex mirrors is thereby employed. We have carried out sub-Doppler resolution spectroscopy of the ν(3) band of CH(4) and the ν(1) band of CH(3)D using a difference-frequency-generation source and the CEAC, and the recorded Lamb dips narrow to 80 kHz (HWHM).

  2. A Matheuristic for the Liner Shipping Network Design Problem with Transit Time Restrictions

    DEFF Research Database (Denmark)

    Brouer, Berit Dangaard; Desaulniers, Guy; Karsten, Christian Vad

    2015-01-01

    We present a mathematical model for the liner shipping network design problem with transit time restrictions on the cargo flow. We extend an existing matheuristic for the liner shipping network design problem to consider transit time restrictions. The matheuristic is an improvement heuristic, where...... an integer program is solved iteratively as a move operator in a large-scale neighborhood search. To assess the effects of insertions/removals of port calls, flow and revenue changes are estimated for relevant commodities along with an estimation of the change in the vessel cost. Computational results...... on the benchmark suite LINER-LIB are reported, showing profitable networks for most instances. We provide insights on causes for rejecting demand and the average speed per vessel class in the solutions obtained....

  3. Transition from anticipatory to lag synchronization via complete synchronization in time-delay systems.

    Science.gov (United States)

    Senthilkumar, D V; Lakshmanan, M

    2005-01-01

    The existence of anticipatory, complete, and lag synchronization in a single system having two different time delays, that is, feedback delay tau1 and coupling delay tau2, is identified. The transition from anticipatory to complete synchronization and from complete to lag synchronization as a function of coupling delay tau2 with a suitable stability condition is discussed. In particular, it is shown that the stability condition is independent of the delay times tau1 and tau2. Consequently, for a fixed set of parameters, all the three types of synchronizations can be realized. Further, the emergence of exact anticipatory, complete, or lag synchronization from the desynchronized state via approximate synchronization, when one of the system parameters (b2) is varied, is characterized by a minimum of the similarity function and the transition from on-off intermittency via periodic structure in the laminar phase distribution.

  4. A transit-time flow meter for measuring milliliter per minute liquid flow

    DEFF Research Database (Denmark)

    Yang, Canqian; Kymmel, Mogens; Søeberg, Henrik

    1988-01-01

    A transit-time flow meter, using periodic temperature fluctuations as tracers, has been developed for measuring liquid flow as small as 0.1 ml/min in microchannels. By injecting square waves of heat into the liquid flow upstream with a tiny resistance wire heater, periodic temperature fluctuations...... are generated downstream. The fundamental frequency phase shift of the temperature signal with respect to the square wave is found to be a linear function of the reciprocal mean velocity of the fluid. The transit-time principle enables the flow meter to have high accuracy, better than 0.2%, and good linearity....... This flow meter will be used to measure and control the small liquid flow in microchannels in flow injection analysis. Review of Scientific Instruments is copyrighted by The American Institute of Physics....

  5. An Approach to Optimize the Departure Times of Transit Vehicles with Strict Capacity Constraints

    Directory of Open Access Journals (Sweden)

    Huimin Niu

    2013-01-01

    Full Text Available This paper focuses on an urban transit line which connects several residential areas and a workplace during the morning rush hours. The congestion is represented by some passengers who must wait for an extended duration and board the next or the third departure vehicles. This paper divides the time horizon equally into several small periods to measure the dynamic passenger demands. Under period-dependent demand conditions, a biobjective optimization model is developed to determine the departure times of transit vehicles at the start station with strict capacity constraints, in which a heuristic algorithm based on intelligent search and local improvement is designed to solve the model. The developed model can address the case in which more than two passengers arrive at a station simultaneously during one same period and calculate the number of boarded passengers. Finally, the model and algorithm have been successfully verified by a numerical example.

  6. Thresholds for the slope ratio in determining transition time and quantifying diffuser performance in situ

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Jacobsen, Finn; Brunskog, Jonas

    2012-01-01

    This study is concerned with an objective measure called the slope ratio that can detect acoustic defects due to unexpected pressure increases such as strong reflections and coincidental constructive interference. The slope ratio is the ratio of the instantaneous slope to the mean slope in a decay...... curve. The slope ratio was suggested for determining the room acoustic transition time experimentally, but its threshold criteria have not been thoroughly investigated. The thresholds for the slope ratio, particularly for applications such as determining the room acoustic transition time and quantifying...... in situ diffuseness, are examined for various room impulse responses. For the tested rooms, a slope ratio threshold of 11 gives the most consistent and systematic results....

  7. Time-gated single-photon detection module with 110 ps transition time and up to 80 MHz repetition rate

    Energy Technology Data Exchange (ETDEWEB)

    Buttafava, Mauro, E-mail: mauro.buttafava@polimi.it; Boso, Gianluca; Ruggeri, Alessandro; Tosi, Alberto [Politecnico di Milano, Dipartimento di Elettronica, Informazione e Bioingegneria, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy); Dalla Mora, Alberto [Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo Da Vinci 32, 20133 Milano (Italy)

    2014-08-15

    We present the design and characterization of a complete single-photon counting module capable of time-gating a silicon single-photon avalanche diode with ON and OFF transition times down to 110 ps, at repetition rates up to 80 MHz. Thanks to this sharp temporal filtering of incoming photons, it is possible to reject undesired strong light pulses preceding (or following) the signal of interest, allowing to increase the dynamic range of optical acquisitions up to 7 decades. A complete experimental characterization of the module highlights its very flat temporal response, with a time resolution of the order of 30 ps. The instrument is fully user-configurable via a PC interface and can be easily integrated in any optical setup, thanks to its small and compact form factor.

  8. Analysis of Time of Day Fare Discounts on Urban Mass Transit Travel Behavior, Crowding, and Waiting Time

    Directory of Open Access Journals (Sweden)

    Xiao Guo

    2014-01-01

    Full Text Available Every morning, commuters select the regularly dispatched urban mass transit for traveling from a residential area to a workplace. This paper aims to find an optimal discount fare and time intervals on morning peak hour. As a direct and flexible traffic economic instrument, fares can influence commuters’ behavior. Therefore, fare discount has been proposed to regulate traffic flow in different time. Two models have been analyzed to describe it with schedule delay because of the travel demand size. The first objective function is constructed on pressure equalization when the travel demand is small. The other objective function is to minimize total waiting time when the travel demand is large. In the end, numerical examples based on an artificial network are performed to characterize fare discount models.

  9. Numerical study of long-time dynamics and ergodic-nonergodic transitions in dense simple fluids

    Science.gov (United States)

    McCowan, David D.

    2015-08-01

    Since the mid-1980s, mode-coupling theory (MCT) has been the de facto theoretic description of dense fluids and the transition from the fluid state to the glassy state. MCT, however, is limited by the approximations used in its construction and lacks an unambiguous mechanism to institute corrections. We use recent results from a new theoretical framework—developed from first principles via a self-consistent perturbation expansion in terms of an effective two-body potential—to numerically explore the kinetics of systems of classical particles, specifically hard spheres governed by Smoluchowski dynamics. We present here a full solution for such a system to the kinetic equation governing the density-density time correlation function and show that the function exhibits the characteristic two-step decay of supercooled fluids and an ergodic-nonergodic transition to a dynamically arrested state. Unlike many previous numerical studies—and in stark contrast to experiment—we have access to the full time and wave-number range of the correlation function with great precision and are able to track the solution unprecedentedly close to the transition, covering nearly 15 decades in scaled time. Using asymptotic approximation techniques analogous to those developed for MCT, we fit the solution to predicted forms and extract critical parameters. We find complete qualitative agreement with known glassy behavior (e.g. power-law divergence of the α -relaxation time scale in the ergodic phase and square-root growth of the glass form factors in the nonergodic phase), as well as some limited quantitative agreement [e.g. the transition at packing fraction η*=0.60149761 (10 ) ] , consistent with previous static solutions under this theory and with comparable colloidal suspension experiments. However, most importantly, we establish that this new theory is able to reproduce the salient features seen in other theories, experiments, and simulations but has the advantages of being

  10. Time-Averaged Behaviour at the Critical Parameter Point of Transition to Spatiotemporal Chaos

    Institute of Scientific and Technical Information of China (English)

    贺凯芬

    2001-01-01

    A time-averaged behaviour is found to be important for investigating the critical behaviour in parameter space for the transition from temporal chaos to spatiotemporal chaos by using an energy representation. Considering any wave solution as a superposition of the steady wave with its perturbation wave, we find that when approaching the critical parameter point the averaged positive interaction energy for the k = 1 mode becomes competitive with the negative one, with the summation displaying a scaling behaviour of power law.

  11. Some properties of asymmetric Hopfield neural networks with finite time of transition between states

    Science.gov (United States)

    Suleimenov, Ibragim; Mun, Grigoriy; Panchenko, Sergey; Pak, Ivan

    2016-11-01

    There were implemented samples of asymmetric Hopfield neural networks which have finite time of transition from one state to another. It was shown that in such systems, various oscillation modes could occur. It was revealed that the oscillation of the output signal of certain neuron could be treated as extra logical variable, which describes the state of the neuron. Asymmetric Hopfield neural networks are described in terms of ternary logic. Such logic may be employed in image recognition procedure.

  12. The Clinical Value of Dual Time Point F-18 FDG PET/CT Imaging for the Differentiation of Colonic Focal Uptake Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Suk; Lim, Seok Tae; Jeong, Young Jin; Kim, Dong Wook; Jeong, Hwan Jeong; Sohn, Myung Hee [Chonbuk National University Medical School and Hospital, Jeonju (Korea, Republic of)

    2009-08-15

    F-18 FDG can be accumulated in the liver, bowel, kidney, urinary tract, and muscles physiologically. The aim of this study was to evaluate the clinical value of dual time point 18F-FDG PET/CT imaging for the differentiation of the colonic focal uptake lesions. One hundred thirty two patients (M:F=77:55, Age 62.8{+-}11.6 years) underwent {sup 18}F-FDG PET/CT at two time points, prospectively: early image at 50-60 min and delayed image at 4-4.5 hours after the intravenous injection of {sup 18}F-FDG. Focally increased uptake lesions on early images but disappeared or shifted on delayed images defined a physiological uptake. For the differential evaluation of persistent focal uptake lesions on delayed images, colonoscopy and histopathologic examination were performed. SUVmax changes between early and delayed images were also compared. Among the 132 patients, 153 lesions of focal colonic uptake were detected on early images of {sup 18}F-FDG PET/CT. Of these, 72 (47.1%) lesions were able to judge with physiological uptake because the focal increased uptake disappeared from delayed image. Among 81 lesions which was showed persistent increased uptake in delayed image, 61 (75.3%) lesions were confirmed as the malignant tumor and 14 (17.3%) lesions were confirmed as the benign lesions including adenoma and inflammatory disease. Remaining 6 (7.4%) lesions were confirmed as the physiological uptake because there was no particular lesion in the colonoscopy. In the malignant lesions, the calculated dual time point change for SUVmax ({delta}%SUVmax) was 20.8%{+-}18.7%, indicating a significant increase in SUVmax between the two point (p<0.01). In contrast, the change in SUVmax for the non-malignant lesions including benign lesions and physiological uptake was -13.7%{+-}24.2%. For the differentiation of the malignant and non-malignant focal colonic uptake lesions, {delta}%SUVmax was the most effective parameter, and the cut-off value using -5% provided the best sensitivity

  13. HST Time-Series Photometry of the Transiting Planet of HD 209458

    CERN Document Server

    Brown, T M; Gilliland, R L; Noyes, R W; Burrows, A; Brown, Timothy M.; Charbonneau, David; Gilliland, Ronald L.; Noyes, Robert W.; Burrows, Adam

    2001-01-01

    We have observed 4 transits of the planet of HD 209458 using the STIS spectrograph on HST. Summing the recorded counts over wavelength between 582 nm and 638 nm yields a photometric time series with 80 s time sampling and relative precision of about 1.1E-4 per sample. The folded light curve can be fit within observational errors using a model consisting of an opaque circular planet transiting a limb-darkened stellar disk. In this way we estimate the planetary radius R_p = 1.347 +/- 0.060 R_Jup, the orbital inclination i = 86.68 +/- 0.14 degrees, the stellar radius R_* = 1.146 +/- 0.050 R_solar, and one parameter describing the stellar limb darkening. Our estimated radius is smaller than those from earlier studies, but is consistent within measurement errors, and is also consistent with theoretical estimates of the radii of irradiated Jupiter-like planets. Satellites or rings orbiting the planet would, if large enough, be apparent from distortions of the light curve or from irregularities in the transit timing...

  14. Bianchi type-I transit cosmological models with time dependent gravitational and cosmological constants

    CERN Document Server

    Pradhan, Anirudh; Rikhvitsky, Victor

    2013-01-01

    The present study deals with the exact solutions of the Einstein's field equations with variable gravitational and cosmological "constants" for a spatially homogeneous and anisotropic Bianchi type-I space-time. To study the transit behaviour of Universe, we consider a law of variation of scale factor $a(t) = \\left(t^{k} e^{t}\\right)^{\\frac{1}{n}}$ which yields a time dependent deceleration parameter (DP) $q = - 1 + \\frac{nk}{(k + t)^{2}}$, comprising a class of models that depicts a transition of the universe from the early decelerated phase to the recent accelerating phase. We find that the time dependent DP is reasonable for the present day Universe and give an appropriate description of the evolution of the universe. For $n = 0.27k$, we obtain $q_{0} = -0.73$ which is similar to observed value of DP at present epoch. It is also observed that for $n \\geq 2$ and $k = 1$, we obtain a class of transit models of the universe from early decelerating to present accelerating phase. For $k = 0$, the universe has no...

  15. A New Method for Increasing Output Power of a Three-Cavity Transit-Time Oscillator

    Institute of Scientific and Technical Information of China (English)

    HE Jun-Tao; ZHONG Hui-Huang; QIAN Bao-Liang; LIU Yong-Gui

    2004-01-01

    We propose a new method to increase the output power of a three-cavity transit-time oscillator (TC-TTO).Conventional transit-time effect oscillators, such as the split-cavity oscillator (SCO), super-Reltron, and TC-TTO (or double-foil SCO), etc., have a common feature that the span of any modulating cavity is uniform. The new method is to vary the three-cavity spans from uniform to nonuniform. Its configuration is called the nonuniform three-cavity transit-time oscillator (NTC-TTO). Numerical simulations show that the electron-beam is modulated more deeply in certain NTC-TTOs than that in the TC-TTO with the same whole modulating length, and the output microwave power in certain NTC-TTOs is higher than that in the TC-TTO. The experimental results are in agreement with those of the numerical simulations. The results show that the new method can increase the output power of a microwave tube based on the TC-TTO.

  16. Probing the NO2 --> NO+O transition state via time resolved unimolecular decomposition

    Science.gov (United States)

    Ionov, S. I.; Brucker, G. A.; Jaques, C.; Chen, Y.; Wittig, C.

    1993-09-01

    Time resolved, subpicosecond resolution measurements of photoinitiated NO2 unimolecular decomposition rates are reported for expansion cooled and room temperature samples. The molecules are excited by 375-402 nm tunable subpicosecond pulses having bandwidths ≥20 cm-1 to levels which are known to be thorough admixtures of the 2B2 electronically excited state and the 2A1 ground electronic state. Subsequent decomposition is probed by a 226 nm subpicosecond pulse that excites laser-induced fluorescence (LIF) in the NO product. When increasing the amount of excitation over the dissociation threshold, an uneven, ``step-like'' increase of the decomposition rate vs energy is observed for expansion cooled samples. The steps are spaced by ˜100 cm-1 and can be assigned ad hoc to bending at the transition state. Relying on experimental estimates for the near threshold density of states, we point out that simple transition state theory predictions give rates that are consistent with these measured values. The rates are sufficiently rapid to question the assumption of rapid intramolecular vibrational redistribution, which is implicit in transition state theories. In contrast to expansion cooled samples, room temperature samples exhibit a smooth variation of the reaction rate vs photon energy. By comparing rates for rotationally cold and room temperature NO2, the ON-O bond is estimated to be ˜40% longer in the transition state than in the parent molecule.

  17. H/L transition time estimation in JET using conformal predictors

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, S., E-mail: sergio.gonzalez@ciemat.es [Asociacion EURATOM/CIEMAT para Fusion, Madrid 28040 (Spain); Vega, J. [Asociacion EURATOM/CIEMAT para Fusion, Madrid 28040 (Spain); Murari, A. [Consorzio RFX, Associazione EURATOM/ENEA per la Fusione, Padova 4-25127 (Italy); Pereira, A. [Asociacion EURATOM/CIEMAT para Fusion, Madrid 28040 (Spain); Dormido-Canto, S.; Ramirez, J.M. [Departamento de Informatica y Automatica, UNED, Madrid 28040 (Spain)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer H/L transitions have been predicted using H/L and L/H models. Black-Right-Pointing-Pointer Models have been built using conformal predictors to hedge the prediction with confidence and credibility measures. Black-Right-Pointing-Pointer Models have been trained using linear and radial basis function kernels. Black-Right-Pointing-Pointer Conformal measures have proven their usefulness to validate data-driven models. - Abstract: Recent advances in data mining allow the automatic recognition of physical phenomena in the databases of fusion devices without human intervention. This is important to create large databases of physical events (thereby increasing the statistical relevance) in an unattended manner. Important examples are the L/H and H/L transitions. In this contribution, a novel technique is introduced to automatically locate H/L transitions in JET by using conformal predictors. The focus is on H/L transitions because typically there is not a clear signature in the time series of the most widely available signals to recognize the change of confinement. Conformal predictors hedge their prediction by means of two parameters: confidence and credibility. The technique has been based on binary supervised classifiers to separate the samples of the respective confinement modes. Results with several underlying classifiers are presented.

  18. Structural relaxation time and cooling rate of a melt in the glass transition region

    Science.gov (United States)

    Sanditov, D. S.; Sydykov, B. S.

    2015-03-01

    The nature of the parameter involved in the Bartenev equation qτg = C relating the cooling rate of a glass-forming melt to its structural relaxation time in the glass transition region is discussed on the basis of the Volkenshtein-Ptitsyn theory using a number of known relationships. It is established that parameter C for amorphous substances with the same fragility is linearly temperature dependent. This parameter is shown to equal the narrow temperature range δ T g characterizing the liquid-glass transition region (by Nemilov); i.e., C = δ T g. It is concluded that δ T g for most glassy systems is only ˜0.7% of the glass transition temperature T g. The narrowness of temperature range δ T g is explained by the small fluctuation volume fraction f g "frozen" at the glass transition temperature. The concept of a close relationship between constant C and the structural order at T g (i.e., the characteristic of the inner state of a nonequilibrium "frozen" amorphous system) is developed.

  19. EFFECT OF TIME OF TRANSITION FROM MANUSCRIPT TO CURSIVE WRITING UPON SUBSEQUENT PERFORMANCE IN HANDWRITING, SPELLING, AND READING.

    Science.gov (United States)

    OTTO, WAYNE; RARICK, G. LAWRENCE

    THE RELATIONSHIP OF THE HANDWRITING, READING, AND SPELLING PERFORMANCE OF FOURTH- AND SIXTH-GRADE CHILDREN TO THE TRANSITION TIME FROM MANUSCRIPT TO CURSIVE WRITING WAS STUDIED. THE FOUR TRANSITION TIMES WERE EITHER THE FIRST OR SECOND SEMESTER IN GRADE 2 OR THE FIRST OR SECOND SEMESTER IN GRADE 3. HANDWRITING LEGIBILITY WAS MEASURED BY THE…

  20. Hybridization and long-distance colonization at different time scales: towards resolution of long-term controversies in the sweet vernal grasses (Anthoxanthum)

    Science.gov (United States)

    Pimentel, Manuel; Sahuquillo, Elvira; Torrecilla, Zeltia; Popp, Magnus; Catalán, Pilar; Brochmann, Christian

    2013-01-01

    Background and Aims Repeated hybridization and/or polyploidization confound classification and phylogenetic inference, and multiple colonizations at different time scales complicate biogeographical reconstructions. This study investigates whether such processes can explain long-term controversies in Anthoxanthum, and in particular its debated relationship to the genus Hierochloë, the evolution of its conspicuously diverse floral morphology, and the origins of its strikingly disjunct occurrences. A hypothesis for recurrent polyploid formation is proposed. Methods Three plastid (trnH-psbA, trnT-L and trnL-F) and two nuclear (ITS, ETS) DNA regions were sequenced in 57 accessions of 17 taxa (including 161 ETS clones) and Bayesian phylogenetic analyses were conducted. Divergence times were inferred in *BEAST using a strict molecular clock. Key Results Anthoxanthum was inferred as monophyletic and sister to one species of Hierochloë based on the plastid data, whereas the nuclear data suggested that one section (Anthoxanthum section Anthoxanthum) is sister to a clade including the other section (Anthoxanthum section Ataxia) as sister to the genus Hierochloë. This could explain the variation in floral morphology; the aberrant characters in Ataxia seem to result from a Miocene hybridization event between one lineage with one fertile and two sterile florets (the Anthoxanthum lineage) and one which probably had three fertile florets as in extant Hierochloë. The distinct diploid A. gracile lineage originated in the Miocene; all other speciation events, many of them involving polyploidy, were dated to the Late Pliocene to Late Pleistocene. Africa was apparently colonized twice in the Late Pliocene (from the north to afro-alpine eastern Africa, and from south-east Asia to southern Africa), whereas Macaronesia was colonized much later (Late Pleistocene) by a diploid Mediterranean lineage. The widespread European tetraploid A. odoratum originated at least twice. Conclusions

  1. Mean Transit Time as a Predictor of Groundwater Discharge Response in the Upper Colorado River Basin

    Science.gov (United States)

    Solder, J. E.; Heilweil, V. M.; Stolp, B. J.; Susong, D.

    2015-12-01

    The Colorado River and its tributaries support 40 million municipal water users and 5.5 million acres of agriculture in the south western United States (U.S. Bureau of Reclamation, 2012). Recent estimates by Rumsey et al. (2015) suggest that a significant portion (about 50 percent) of surface water flow in the Upper Colorado River Basin (UCRB) is sustained by groundwater discharge to streams. Predicted climate variation (Cook et al., 2015) and increased water demand (U.S. Bureau of Reclamation, 2012) within the UCRB suggest future decreases in groundwater discharge, however transient groundwater responses are not well understood. In this study we calculate groundwater mean transit time (MTT) and transit time distribution (TTD) as predictors of the pattern and timing of groundwater response to hydraulic stress. Samples from nineteen large springs within the UCRB were analyzed for environmental tracers to determine MTT and TTD. The predictive value of the MTT is examined by a statistical analysis of MTT, historical spring discharge records, and the Palmer Hydrological Drought Index. MTTs of the 19 springs range from 10 to 15,000 years with a flow-weighted average of 1,650 years. The composite TTD of the 19 springs suggest that flowpaths representing 45 percent of their combined discharge have transit times greater than 100 years. However, spring discharge records indicate that flow responds to drought on much shorter (0.5 - 6 year) time scales, indicative of a hydraulic pressure response. Springs with shorter MTTs ( 100) also show a hydraulic pressure response. While not fully representative of the UCRB, results from the 19 springs indicate that groundwater discharge responds to climate variation and water-demand imbalances over a relatively short time period of years.

  2. Effect of sodium acid pyrophosphate on ranitidine bioavailability and gastrointestinal transit time.

    Science.gov (United States)

    Koch, K M; Parr, A F; Tomlinson, J J; Sandefer, E P; Digenis, G A; Donn, K H; Powell, J R

    1993-07-01

    During development of a ranitidine effervescent oral solution dosage form, a marked decrease was observed in the extent of ranitidine absorption relative to the conventional oral tablet. Two studies were conducted in healthy volunteers to confirm the involvement of an excipient, SAPP (sodium acid pyrophosphate), and the mechanism of interaction, altered gastrointestinal transit. The first study (n = 12) involved single-dose crossover comparisons of (A) 150 mg ranitidine with 1132 mg SAPP versus (B) 150 mg ranitidine and (C) 150 mg ranitidine with all the effervescent tablet excipients except SAPP versus (D) a 150-mg ranitidine effervescent tablet, all administered as oral solutions. Serum ranitidine AUC, Cmax, and tmax were compared using two one-sided t test 90% confidence intervals (CI). Comparing treatments A to B and D to C, all 90% CI were below the 80-120% range, indicating significantly less extensive ranitidine absorption (54% based on AUC) from the oral solutions containing SAPP. The second study (n = 12) was a single-dose crossover comparing 50 microCi 111 InCl solutions with and without 1132 mg SAPP. Gastrointestinal transit times, determined by scintigraphic imaging, were compared between treatments. Gastric emptying time was unchanged, but small intestinal transit time was decreased to 56% in the presence of SAPP. More rapid small intestinal transit associated with an excipient of a solution dosage form apparently resulted in a decreased extent of ranitidine absorption. This observation contradicts the conventional wisdom that oral solutions are unlikely to fall short of bioequivalence relative to solid oral formulations.

  3. Glass transition temperature of PIB, PDMS and PMMA from small-time simulations

    Science.gov (United States)

    Duki, Solomon; Tsige, Mesfin; Taylor, Philip

    2009-03-01

    We have applied some new techniques to obtain predictions of the glass transition temperatures Tg of poly(isobutylene), poly(dimethyl-siloxane), and poly(methyl methacrylate) from small-time atomistic molecular dynamics simulations. The different fragilities of these materials are reflected in the results of the simulations. One approach involved measurement of the apparent softening of the ``cage'' in which a monomer is bound, while another involved studying autocorrelation of a convolution of the velocity with a smoothing function in order to detect the frequency of escapes from the ``cage.'' To check the accuracy of the short-time methods, the Tg of the polymers was also found using conventional diffusion simulations in which the rate of increase of the root mean squared displacement of an atom, monomer, or molecule is measured at very long times. The economical short-time simulations yielded results for Tg that were identical to those of the computer-intensive long-time simulations.

  4. Molecular motions and phase transitions. NMR relaxation times studies of several lecithins.

    OpenAIRE

    Bar-Adon, R; Gilboa, H

    1981-01-01

    The spin-lattice relaxation time, T1, and the dipolar energy relaxation time, TD, were measured as a function of temperature. The materials studied were samples of anhydrous L-dipalmitoyl lecithin, DL-dipalmitoyl lecithin, L-dimyristoyl lecithin, DL-dimyristoyl lecithin and their monohydrates, and of anhydrous egg yolk lecithin. It is shown that TD is a much more sensitive parameter than T1 for the determination of the Chapman phase transition. Comparison between T1 and TD provides informatio...

  5. Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability

    CERN Document Server

    Steffen, Jason H; Agol, Eric; Ford, Eric B; Morehead, Robert C; Cochran, William D; Lissauer, Jack J; Adams, Elisabeth R; Borucki, William J; Bryson, Steve; Caldwell, Douglas A; Dupree, Andrea; Jenkins, Jon M; Robertson, Paul; Rowe, Jason F; Seader, Shawn; Thompson, Susan; Twicken, Joseph D

    2012-01-01

    We confirm 27 planets in 13 planetary systems by showing the existence of statistically significant anti-correlated transit timing variations (TTVs), which demonstrates that the planet candidates are in the same system, and long-term dynamical stability, which places limits on the masses of the candidates---showing that they are planetary. %This overall method of planet confirmation was first applied to \\kepler systems 23 through 32. All of these newly confirmed planetary systems have orbital periods that place them near first-order mean motion resonances (MMRs), including 6 systems near the 2:1 MMR, 5 near 3:2, and one each near 4:3, 5:4, and 6:5. In addition, several unconfirmed planet candidates exist in some systems (that cannot be confirmed with this method at this time). A few of these candidates would also be near first order MMRs with either the confirmed planets or with other candidates. One system of particular interest, Kepler-56 (KOI-1241), is a pair of planets orbiting a 12th magnitude, giant sta...

  6. Phase transitions in the common brainstem and related systems investigated by nonstationary time series analysis.

    Science.gov (United States)

    Lambertz, M; Vandenhouten, R; Grebe, R; Langhorst, P

    2000-01-14

    Neuronal activities of the reticular formation (RF) of the lower brainstem and the nucleus tractus solitarii (NTS, first relay station of baroreceptor afferents) were recorded together in the anesthized dog with related parameters of EEG, respiration and cardiovascular system. The RF neurons are part of the common brainstem system (CBS) which participates in regulation and coordination of cardiovascular, respiratory, somatomotor systems, and vigilance. Multiple time series of these physiological subsystems yield useful information about internal dynamic coordination of the organism. Essential problems are nonlinearity and instationarity of the signals, due to the dynamic complexity of the systems. Several time-resolving methods are presented to describe nonlinear dynamic couplings in the time course, particularly during phase transitions. The methods are applied to the recorded signals representing the complex couplings of the physiological subsystems. Phase transitions in these systems are detected by recurrence plots of the instationary signals. The pointwise transinformation and the pointwise conditional coupling divergence are measures of the mutual interaction of the subsystems in the state space. If the signals show marked rhythms, instantaneous frequencies and their shiftings are demonstrated by time frequency distributions, and instantaneous phase differences show couplings of oscillating subsystems. Transient signal components are reconstructed by wavelet packet time selective transient reconstruction. These methods are useful means for analyzing coupling characteristics of the complex physiological system, and detailed analyses of internal dynamic coordination of subsystems become possible. During phase transitions of the functional organization (a) the rhythms of the central neuronal activities and the peripheral systems are altered, (b) changes in the coupling between CBS neurons and cardiovascular signals, respiration and the EEG, and (c) between NTS

  7. Distributional behavior of diffusion coefficients obtained by single trajectories in annealed transit time model

    Science.gov (United States)

    Akimoto, Takuma; Yamamoto, Eiji

    2016-12-01

    Local diffusion coefficients in disordered systems such as spin glass systems and living cells are highly heterogeneous and may change over time. Such a time-dependent and spatially heterogeneous environment results in irreproducibility of single-particle-tracking measurements. Irreproducibility of time-averaged observables has been theoretically studied in the context of weak ergodicity breaking in stochastic processes. Here, we provide rigorous descriptions of equilibrium and non-equilibrium diffusion processes for the annealed transit time model, which is a heterogeneous diffusion model in living cells. We give analytical solutions for the mean square displacement (MSD) and the relative standard deviation of the time-averaged MSD for equilibrium and non-equilibrium situations. We find that the time-averaged MSD grows linearly with time and that the time-averaged diffusion coefficients are intrinsically random (irreproducible) even in the long-time measurements in non-equilibrium situations. Furthermore, the distribution of the time-averaged diffusion coefficients converges to a universal distribution in the sense that it does not depend on initial conditions. Our findings pave the way for a theoretical understanding of distributional behavior of the time-averaged diffusion coefficients in disordered systems.

  8. Time-resolved lattice measurements of shock-induced phase transitions in polycrystalline materials

    Science.gov (United States)

    Milathianaki, Despina

    The response of materials under extreme temperature and pressure conditions is a topic of great significance because of its relevance in astrophysics, geophysics, and inertial confinement fusion. In recent years, environments exceeding several hundred gigapascals in pressure have been produced in the laboratory via laser-based dynamic loading techniques. Shock-loading is of particular interest as the shock provides a fiducial for measuring time-dependent processes in the lattice such as phase transitions. Time-resolved x-ray diffraction is the only technique that offers an insight into these shock-induced processes at the relevant spatial (atomic) and temporal scales. In this study, nanosecond resolution x-ray diffraction techniques were developed and implemented towards the study of shock-induced phase transitions in polycrystalline materials. More specifically, the capability of a focusing x-ray diffraction geometry in high-resolution in situ lattice measurements was demonstrated by probing shock-compressed Cu and amorphous metallic glass samples. In addition, simultaneous lattice and free surface velocity measurements of shock-compressed Mg in the ambient hexagonal close packed (hcp) and shock-induced body centered cubic (bcc) phases between 12 and 45 GPa were performed. These measurements revealed x-ray diffraction signals consistent with a compressed bcc lattice above a shock pressure of 26.2+/-1.3 GPa, thus capturing for the first time direct lattice evidence of a shock-induced hcp to bcc phase transition in Mg. Our measurement of the hcp-bcc phase boundary in Mg was found to be consistent with the calculated boundary from generalized pseudopotential theory in the pressure and temperature region intersected by the principal shock Hugoniot. Furthermore, the subnanosecond timescale of the phase transition implied by the shock-loading conditions was in agreement with the kinetics of a martensitic transformation. In conclusion, we report on the progress and

  9. Expression of synaptophysin in colonic wall in patients with slow transit constipation%突触素在慢传输型便秘患者结肠壁的表达

    Institute of Scientific and Technical Information of China (English)

    孔利霞; 宋建亭; 赵士彭

    2014-01-01

    目的:研究突触素( SY )在慢传输型便秘( STC )患者肠神经系统中的表达情况。方法选择肠道造影提示有结肠痉挛并经手术证实 STC 者20例,取其乙状结肠(痉挛段)及横结肠(近端非痉挛段)肠壁标本为实验组;无结肠痉挛的 STC 患者20例,取其乙状结肠及横结肠肠壁标本为对照组。2组标本均进行免疫组化检测,分析突触素在 STC 患者结肠壁的表达情况。结果突触素在2组便秘患者结肠壁肌层的表达均比黏膜下层表达增高(P<0.05),实验组的横结肠黏膜下层突触素的表达明显低于对照组(P <0.05),其余组间突触素的表达差异无统计学意义。结论 STC患者横结肠与乙状结肠结肠壁肌层突触素的表达均明显高于黏膜下层的表达,与其生理功能相一致。乙状结肠痉挛的发生与突触素的表达水平无相关。突触素在结肠痉挛区近端横结肠黏膜下层的表达减少,可能与其远端乙状结肠肠管持续痉挛导致其近端横结肠发生进行性退变引起代偿性、继发性肠管扩大肥厚造成的肠管扩张和蠕动减弱相关。%Objective It is tO explOre the expressiOn Of synaptOphysin( SY)in the enteric nervOus system in slOw transit cOnstipatiOn( STC)patients. Methods 20 cases with cOlOn spasms prOmpted by intestinal tract imaging and cOnfirmed by sur-gery were selected in which a specimen each Of the sigmOid cOlOn wall( the part Of spasm )and transverse cOlOn wall( the prOximal part Of nO spasm)was made as the experimental grOup;20 STC patients with nO cOlOn spasm were selected and the same specimen frOm the same part Of cOlOnic wall was made as the cOntrOl grOup. The expressiOn Of SY in cOlOnic wall was de-tected by immunOhistOchemical methOd in the specimen Of bOth grOups. Results The expressiOn Of SY in cOlOn wall muscle lay-er was higher than that Of SY in submucOsa layer in the patients with STC in bOth grOups(P <0

  10. Colon Polyps

    Science.gov (United States)

    ... whole grains. Reduce your fat intake. Limit alcohol consumption. Don't use tobacco. Stay physically active and maintain a healthy body weight. Talk to your doctor about calcium. Studies have shown that increasing your consumption of calcium may help prevent recurrence of colon ...

  11. Colon Cancer

    Centers for Disease Control (CDC) Podcasts

    2013-11-05

    In this podcast, Dr. Tom Frieden, CDC Director, discusses colon cancer and the importance of early detection.  Created: 11/5/2013 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 3/6/2014.

  12. Learning about Colon Cancer

    Science.gov (United States)

    ... What do we know about heredity and colon cancer? Colon cancer, a malignant tumor of the large intestine, ... page Additional Resources for Information on Hereditary Colon Cancer Colon and Rectal Cancer Information [cancer.gov] The most ...

  13. Comparison of noninvasive pulse transit time estimates as markers of blood pressure using invasive pulse transit time measurements as a reference.

    Science.gov (United States)

    Gao, Mingwu; Olivier, N Bari; Mukkamala, Ramakrishna

    2016-05-01

    Pulse transit time (PTT) measured as the time delay between invasive proximal and distal blood pressure (BP) or flow waveforms (invasive PTT [I-PTT]) tightly correlates with BP PTT estimated as the time delay between noninvasive proximal and distal arterial waveforms could therefore permit cuff-less BP monitoring. A popular noninvasive PTT estimate for this application is the time delay between ECG and photoplethysmography (PPG) waveforms (pulse arrival time [PAT]). Another estimate is the time delay between proximal and distal PPG waveforms (PPG-PTT). PAT and PPG-PTT were assessed as markers of BP over a wide physiologic range using I-PTT as a reference. Waveforms for determining I-PTT, PAT, and PPG-PTT through central arteries were measured from swine during baseline conditions and infusions of various hemodynamic drugs. Diastolic, mean, and systolic BP varied widely in each subject (group average (mean ± SE) standard deviation between 25 ± 2 and 36 ± 2 mmHg). I-PTT correlated well with all BP levels (group average R(2) values between 0.86 ± 0.03 and 0.91 ± 0.03). PPG-PTT also correlated well with all BP levels (group average R(2) values between 0.81 ± 0.03 and 0.85 ± 0.02), and its R(2) values were not significantly different from those of I-PTT PAT correlated best with systolic BP (group average R(2) value of 0.70 ± 0.04), but its R(2) values for all BP levels were significantly lower than those of I-PTT (P < 0.005) and PPG-PTT (P < 0.02). The pre-ejection period component of PAT was responsible for its inferior correlation with BP In sum, PPG-PTT was not different from I-PTT and superior to the popular PAT as a marker of BP.

  14. Time-and pH-dependent colon-specific drug delivery for orally administered diclofenac sodium and 5-aminosalicylic acid

    Institute of Scientific and Technical Information of China (English)

    Gang Cheng; Feng An; Mei-Juan Zou; Jin Sun; Xiu-Hua Hao; Yun-Xia He

    2004-01-01

    AIM: To investigate Time- and pH-dependent colon-specific drug delivery systems (CDDS) for orally administered diclofenac sodium (DS) and 5-aminosalicylic acid (5-ASA), respectively.METHODS: DS tablets and 5-ASA pellets were coated by ethylcellulose (EC) and methacrylic acid copolymers (Eudragit[] L100 and S100), respectively. The in vitro release behavior of the DS coated tablets and 5-ASA coated pellets were examined, and then in vivo absorption kinetics of DS coated tablets in dogs were further studied.RESULTS: Release profile of time-dependent DS coated tablets was not influenced by pH of the dissolution medium,but the lag time of DS release was primarily controlled by the thickness of the coating layer. The thicker the coating layer, the longer the lag time of DS release is. On the contrary, in view of the pH-dependent 5-ASA coated pellets,5-ASA release was significantly governed by pH. Moreover,the 5-ASA release features from the coated pellets depended upon both the combination ratio of the Eudragit[] L100 and S100 pH-sensitive copolymers in the coating formulation and the thickness of the coating layer. The absorption kinetic studies of the DS coated tablets in dogs demonstrated that in vivo lag time of absorption was in a good agreement with in vitro lag time of release.CONCLUSION: Two types of CDDS, prepared herein by means of the regular coating technique, are able to achieve site-specific drug delivery targeting at colon following oral administration, and provide a promising strategy to control drug release targeting the desired lower gastrointestinal region.

  15. Pulse transit time differential measurement by fiber Bragg grating pulse recorder.

    Science.gov (United States)

    Umesh, Sharath; Padma, Srivani; Ambastha, Shikha; Kalegowda, Anand; Asokan, Sundarrajan

    2015-05-01

    The present study reports a noninvasive technique for the measurement of the pulse transit time differential (PTTD) from the pulse pressure waveforms obtained at the carotid artery and radial artery using fiber Bragg grating pulse recorders (FBGPR). PTTD is defined as the time difference between the arrivals of a pulse pressure waveform at the carotid and radial arterial sites. The PTTD is investigated as an indicator of variation in the systolic blood pressure. The results are validated against blood pressure variation obtained from a Mindray Patient Monitor. Furthermore, the pulse wave velocity computed from the obtained PTTD is compared with the pulse wave velocity obtained from the color Doppler ultrasound system and is found to be in good agreement. The major advantage of the PTTD measurement via FBGPRs is that the data acquisition system employed can simultaneously acquire pulse pressure waveforms from both FBGPRs placed at carotid and radial arterial sites with a single time scale, which eliminates time synchronization complexity.

  16. Time-varying coupling functions: Dynamical inference and cause of synchronization transitions.

    Science.gov (United States)

    Stankovski, Tomislav

    2017-02-01

    Interactions in nature can be described by their coupling strength, direction of coupling, and coupling function. The coupling strength and directionality are relatively well understood and studied, at least for two interacting systems; however, there can be a complexity in the interactions uniquely dependent on the coupling functions. Such a special case is studied here: synchronization transition occurs only due to the time variability of the coupling functions, while the net coupling strength is constant throughout the observation time. To motivate the investigation, an example is used to present an analysis of cross-frequency coupling functions between delta and alpha brain waves extracted from the electroencephalography recording of a healthy human subject in a free-running resting state. The results indicate that time-varying coupling functions are a reality for biological interactions. A model of phase oscillators is used to demonstrate and detect the synchronization transition caused by the varying coupling functions during an invariant coupling strength. The ability to detect this phenomenon is discussed with the method of dynamical Bayesian inference, which was able to infer the time-varying coupling functions. The form of the coupling function acts as an additional dimension for the interactions, and it should be taken into account when detecting biological or other interactions from data.

  17. Evaluation by computerized morphometry of histopathological alterations of the colon wall in segments with and without intestinal transit in rats Avaliação por morfometria computadorizada das alterações histopatológicas da parede cólica em segmentos com e sem trânsito intestinal em ratos

    Directory of Open Access Journals (Sweden)

    Marcos Vieira de Sousa

    2008-10-01

    Full Text Available PURPOSE: To evaluate histopathological alterations of the colon wall in segments with and without intestinal transit, by computer-assisted imaging, and to correlate these with the length of time diversion. METHODS: Thirty male Wistar rats were subjected to intestinal transit diversion by a proximal colostomy and distal mucosa fistula. The animals were divided into three experimental groups according to how long after the initial surgical procedure they were sacrificed: six, twelve and eighteen weeks. Colon segments with and without transit were subjected to histopathological study. The variables colon crypt length, mucosal ulceration, muscle layer thickness of the muscularis mucosa, submucosa and muscularis propria, vascular congestion, number of caliciform cells, inflammatory grade and degree of inflammation, comparing the two colon segments in the different experimental groups were studied. Intestinal crypt length, muscle layer thickness of the mucosa, submucosa and muscularis propria and caliciform cells were measured by computer-assisted imaging method. Mean equality, variance analysis and correlation tests were used in the statistical analysis, and the significance level was set at 5%. RESULTS: Comparison between segments with and without transit showed that the latter presented reduced length of colon crypts and increased muscle layer thickness of the muscularis mucosa, submucosa and muscularis propria. There were greater quantities of ulceration of the mucosal and greater degree of inflammation with increasing time without transit. Mucosal ulceration, submucosal vascular congestion, increased thickness of the submucosal and muscularis propria layers, presence of caliciform cells, inflammatory infiltrate and inflammatory grade correlated significantly with the length of time without transit. CONCLUSIONS: Histological alterations occurred in all layers of the colon wall, in the segments without intestinal transit. Ulcerations in the

  18. The problem with simple lumped parameter models: Evidence from tritium mean transit times

    Science.gov (United States)

    Stewart, Michael; Morgenstern, Uwe; Gusyev, Maksym; Maloszewski, Piotr

    2017-04-01

    Simple lumped parameter models (LPMs) based on assuming homogeneity and stationarity in catchments and groundwater bodies are widely used to model and predict hydrological system outputs. However, most systems are not homogeneous or stationary, and errors resulting from disregard of the real heterogeneity and non-stationarity of such systems are not well understood and rarely quantified. As an example, mean transit times (MTTs) of streamflow are usually estimated from tracer data using simple LPMs. The MTT or transit time distribution of water in a stream reveals basic catchment properties such as water flow paths, storage and mixing. Importantly however, Kirchner (2016a) has shown that there can be large (several hundred percent) aggregation errors in MTTs inferred from seasonal cycles in conservative tracers such as chloride or stable isotopes when they are interpreted using simple LPMs (i.e. a range of gamma models or GMs). Here we show that MTTs estimated using tritium concentrations are similarly affected by aggregation errors due to heterogeneity and non-stationarity when interpreted using simple LPMs (e.g. GMs). The tritium aggregation error series from the strong nonlinearity between tritium concentrations and MTT, whereas for seasonal tracer cycles it is due to the nonlinearity between tracer cycle amplitudes and MTT. In effect, water from young subsystems in the catchment outweigh water from old subsystems. The main difference between the aggregation errors with the different tracers is that with tritium it applies at much greater ages than it does with seasonal tracer cycles. We stress that the aggregation errors arise when simple LPMs are applied (with simple LPMs the hydrological system is assumed to be a homogeneous whole with parameters representing averages for the system). With well-chosen compound LPMs (which are combinations of simple LPMs) on the other hand, aggregation errors are very much smaller because young and old water flows are treated

  19. Study of phase transitions from short-time non-equilibrium behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Albano, E V; Bab, M A; Baglietto, G; Borzi, R A; Grigera, T S; Loscar, E S; Rodriguez, D E; Rubio Puzzo, M L; Saracco, G P [Instituto de Investigaciones FisicoquImicas Teoricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, c.c. 16, suc. 4, 1900 La Plata (Argentina)

    2011-02-15

    We review recent progress in the understanding of phase transitions and critical phenomena, obtained by means of numerical simulations of the early dynamic evolution of systems prepared at well-specified initial conditions. This field has seen exhaustive scientific research during the last decade, when the renormalization-group (RG) theoretical results obtained at the end of the 1980s were applied to the interpretation of dynamic Monte Carlo simulation results. While the original RG theory is restricted to critical phenomena under equilibrium conditions, numerical simulations have been applied to the study of far-from-equilibrium systems and irreversible phase transitions, the investigation of the behaviour of spinodal points close to first-order phase transitions and the understanding of the early-time evolution of self-organized criticality (SOC) systems when released far form the SOC regime. The present review intends to provide a comprehensive overview of recent applications in those fields, which can give the flavour of the main ideas, methods and results, and to discuss the directions for further studies. All of these numerical results pose new and interesting theoretical challenges that remain as open questions to be addressed by new research in the coming years.

  20. Critical Space-Time Networks and Geometric Phase Transitions from Frustrated Edge Antiferromagnetism

    CERN Document Server

    Trugenberger, Carlo A

    2015-01-01

    Recently I proposed a simple dynamical network model for discrete space-time which self-organizes as a graph with Hausdorff dimension d_H=4. The model has a geometric quantum phase transition with disorder parameter (d_H-d_s) where d_s is the spectral dimension of the dynamical graph. Self-organization in this network model is based on a competition between a ferromagnetic Ising model for vertices and an antiferromagnetic Ising model for edges. In this paper I solve a toy version of this model defined on a bipartite graph in the mean field approximation. I show that the geometric phase transition corresponds exactly to the antiferromagnetic transition for edges, the dimensional disorder parameter of the former being mapped to the staggered magnetization order parameter of the latter. The model has a critical point with long-range correlations between edges, where a continuum random geometry can be defined, exactly as in Kazakov's famed 2D random lattice Ising model but now in any number of dimensions.

  1. A mechanism-based approach for absorption modeling: the Gastro-Intestinal Transit Time (GITT) model.

    Science.gov (United States)

    Hénin, Emilie; Bergstrand, Martin; Standing, Joseph F; Karlsson, Mats O

    2012-06-01

    Absorption models used in the estimation of pharmacokinetic drug characteristics from plasma concentration data are generally empirical and simple, utilizing no prior information on gastro-intestinal (GI) transit patterns. Our aim was to develop and evaluate an estimation strategy based on a mechanism-based model for drug absorption, which takes into account the tablet movement through the GI transit. This work is an extension of a previous model utilizing tablet movement characteristics derived from magnetic marker monitoring (MMM) and pharmacokinetic data. The new approach, which replaces MMM data with a GI transit model, was evaluated in data sets where MMM data were available (felodipine) or not available (diclofenac). Pharmacokinetic profiles in both datasets were well described by the model according to goodness-of-fit plots. Visual predictive checks showed the model to give superior simulation properties compared with a standard empirical approach (first-order absorption rate + lag-time). This model represents a step towards an integrated mechanism-based NLME model, where the use of physiological knowledge and in vitro–in vivo correlation helps fully characterize PK and generate hypotheses for new formulations or specific populations.

  2. Swallowing transit times and valleculae residue in stable chronic obstructive pulmonary disease.

    Science.gov (United States)

    de Deus Chaves, Rosane; Chiarion Sassi, Fernanda; Davison Mangilli, Laura; Jayanthi, Shri Krishna; Cukier, Alberto; Zilberstein, Bruno; Furquim de Andrade, Claudia Regina

    2014-04-16

    Breathing and swallowing are physiologically linked to ensure effortless gas exchange during oronasal breathing and to prevent aspiration during swallowing. Studies have indicated consistent aspiration in chronic obstructive pulmonary disease, mainly related to delayed swallowing reflex and problems with lingual propulsion and pharyngeal peristalsis as a result of bilateral weakness and incoordination of the related muscles. The purpose of the present study was to evaluate swallowing transit times and valleculae residue characteristics of stable COPD patients who have no swallowing complaints. Our study population included 20 stable patients with COPD and no swallowing complaints and 20 healthy controls. Swallowing was assessed through videofluoroscopic examination and involved the analysis of the following parameters: (1) pharyngeal stages of deglutition; (2) the duration of bolus movement through the oral cavity and pharynx (i.e. transit times); (3) valleculae residue ratio; (4) penetration/aspiration. Participants of the study did not present any signs of penetration-aspiration for any of the tested consistencies. Patients with COPD presented longer pharyngeal transit times during the ingestion of the liquid consistency and during the ingestion of the paste consistency. Regarding the duration of tongue base contact with the posterior pharyngeal wall, COPD patients also presented longer durations for the liquid and paste consistencies. No significant difference was observed for the distribution of individuals among the different valleculae residue severity levels. Our study suggests that stable COPD patients may present physiological adaptations as a protective swallowing maneuver to avoid aspiration/penetration of pharyngeal contents. Moreover, valleculae residue cannot be seen as an isolated factor when trying to explain swallowing alterations in this population.

  3. How does landscape structure influence catchment transit time across different geomorphic provinces?

    Science.gov (United States)

    Tetzlaff, D.; Seibert, J.; McGuire, K.J.; Laudon, H.; Burns, Douglas A.; Dunn, S.M.; Soulsby, C.

    2009-01-01

    Despite an increasing number of empirical investigations of catchment transit times (TTs), virtually all are based on individual catchments and there are few attempts to synthesize understanding across different geographical regions. Uniquely, this paper examines data from 55 catchments in five geomorphic provinces in northern temperate regions (Scotland, United States of America and Sweden). The objective is to understand how the role of catchment topography as a control on the TTs differs in contrasting geographical settings. Catchment inverse transit time proxies (ITTPs) were inferred by a simple metric of isotopic tracer damping, using the ratio of standard deviation of ??18O in streamwater to the standard deviation of ??18O in precipitation. Quantitative landscape analysis was undertaken to characterize the catchments according to hydrologically relevant topographic indices that could be readily determined from a digital terrain model (DTM). The nature of topographic controls on transit times varied markedly in different geomorphic regions. In steeper montane regions, there are stronger gravitational influences on hydraulic gradients and TTs tend to be lower in the steepest catchments. In provinces where terrain is more subdued, direct topographic control weakened; in particular, where flatter areas with less permeable soils give rise to overland flow and lower TTs. The steeper slopes within this flatter terrain appear to have a greater coverage of freely draining soils, which increase sub-surface flow, therefore increasing TTs. Quantitative landscape analysis proved a useful tool for intercatchment comparison. However, the critical influence of sub-surface permeability and connectivity may limit the transferability of predictive tools of hydrological function based on topographic parameters alone. Copyright ?? 2009 John Wiley & Sons, Ltd.

  4. Detection of Campylobacter bacteria in air samples for continuous real-time monitoring of Campylobacter colonization in broiler flocks.

    Science.gov (United States)

    Olsen, Katja N; Lund, Marianne; Skov, Julia; Christensen, Laurids S; Hoorfar, Jeffrey

    2009-04-01

    Improved monitoring tools are important for the control of Campylobacter bacteria in broiler production. In this study, we compare the sensitivities of detection of Campylobacter by PCR with feces, dust, and air samples during the lifetimes of broilers in two poultry houses and conclude that the sensitivity of detection of Campylobacter in air is comparable to that in other sample materials. Profiling of airborne particles in six poultry houses revealed that the aerodynamic conditions were dependent on the age of the chickens and very comparable among different poultry houses, with low proportions of particles in the 0.5- to 2-microm-diameter range and high proportions in the 2- to 5-microm-diameter range. Campylobacter could also be detected by PCR in air samples collected at the hanging stage during the slaughter process but not at the other stages tested at the slaughterhouse. The exploitation of airborne dust in poultry houses as a sample material for the detection of Campylobacter and other pathogens provides an intriguing possibility, in conjunction with new detection technologies, for allowing continuous or semicontinuous monitoring of colonization status.

  5. Time delay induced transition of gene switch and stochastic resonance in a genetic transcriptional regulatory model

    Science.gov (United States)

    2012-01-01

    Background Noise, nonlinear interactions, positive and negative feedbacks within signaling pathways, time delays, protein oligomerization, and crosstalk between different pathways are main characters in the regulatory of gene expression. However, only a single noise source or only delay time in the deterministic model is considered in the gene transcriptional regulatory system in previous researches. The combined effects of correlated noise and time delays on the gene regulatory model still remain not to be fully understood. Results The roles of time delay on gene switch and stochastic resonance are systematically explored based on a famous gene transcriptional regulatory model subject to correlated noise. Two cases, including linear time delay appearing in the degradation process (case I) and nonlinear time delay appearing in the synthesis process (case II) are considered, respectively. For case I: Our theoretical results show that time delay can induce gene switch, i.e., the TF-A monomer concentration shifts from the high concentration state to the low concentration state ("on"→"off"). With increasing the time delay, the transition from "on" to "off" state can be further accelerated. Moreover, it is found that the stochastic resonance can be enhanced by both the time delay and correlated noise intensity. However, the additive noise original from the synthesis rate restrains the stochastic resonance. It is also very interesting that a resonance bi-peaks structure appears under large additive noise intensity. The theoretical results by using small-delay time-approximation approach are consistent well with our numerical simulation. For case II: Our numerical simulation results show that time delay can also induce the gene switch, however different with case I, the TF-A monomer concentration shifts from the low concentration state to the high concentration state ("off"→"on"). With increasing time delay, the transition from "on" to "off" state can be further

  6. Changes in sleep duration, timing, and quality as children transition to kindergarten.

    Science.gov (United States)

    Cairns, Alyssa; Harsh, John

    2014-01-01

    Sleep can be seen as a biologically driven behavior shaped by cultural context. A "poor fit" occurs when contextual demands for the timing and duration sleep periods are incompatible with the underlying biology. Such contextual factors are well-known for adults, yet little is known of the contextual factors that shape young children's sleep health and to what degree such factors impact sleep duration, timing, and quality. This study attempted to identify how the transition to kindergarten was associated with changes in sleep timing, duration, and quality for children enrolled in preschool prior to attending kindergarten vs. those who were not. Wrist actigraphy in 38 5-year-old children was collected at three longitudinal points before and after the start of kindergarten. Our data suggested that the transition to kindergarten was associated with a reduction in weekday sleep (mostly due to lost napping) and an advance in the weekday nocturnal sleep period that was most pronounced for children not enrolled in preschool prior to kindergarten. These sleep changes paralleled objective and caregiver-reported data of increased sleep pressure that lasted well into the first month of kindergarten.

  7. A general stochastic model for studying time evolution of transition networks

    Science.gov (United States)

    Zhan, Choujun; Tse, Chi K.; Small, Michael

    2016-12-01

    We consider a class of complex networks whose nodes assume one of several possible states at any time and may change their states from time to time. Such networks represent practical networks of rumor spreading, disease spreading, language evolution, and so on. Here, we derive a model describing the dynamics of this kind of network and a simulation algorithm for studying the network evolutionary behavior. This model, derived at a microscopic level, can reveal the transition dynamics of every node. A numerical simulation is taken as an "experiment" or "realization" of the model. We use this model to study the disease propagation dynamics in four different prototypical networks, namely, the regular nearest-neighbor (RN) network, the classical Erdös-Renyí (ER) random graph, the Watts-Strogátz small-world (SW) network, and the Barabási-Albert (BA) scalefree network. We find that the disease propagation dynamics in these four networks generally have different properties but they do share some common features. Furthermore, we utilize the transition network model to predict user growth in the Facebook network. Simulation shows that our model agrees with the historical data. The study can provide a useful tool for a more thorough understanding of the dynamics networks.

  8. Prospects of long-time-series observations from Dome C for transit search

    CERN Document Server

    Rauer, Heike; Erikson, Anders

    2008-01-01

    The detection of transiting extrasolar planets requires high-photometric quality and long-duration photometric stellar time-series. In this paper, we investigate the advantages provided by the Antarctic observing platform Dome C for planet transit detections during its long winter period, which allows for relatively long, uninterrupted time-series. Our calculations include limiting effects due to the Sun and Moon, cloud coverage and the effect of reduced photometric quality for high extinction of target fields. We compare the potential for long time-series from Dome C with a single site in Chile, a three-site low-latitude network as well as combinations of Dome C with Chile and the network, respectively. Dome C is one of the prime astronomical sites on Earth for obtaining uninterrupted long-duration observations in terms of prospects for a high observational duty cycle. The duty cycle of a project can, however, be significantly improved by integrating Dome C into a network of sites.

  9. Smartphone-based Continuous Blood Pressure Measurement Using Pulse Transit Time.

    Science.gov (United States)

    Gholamhosseini, Hamid; Meintjes, Andries; Baig, Mirza; Linden, Maria

    2016-01-01

    The increasing availability of low cost and easy to use personalized medical monitoring devices has opened the door for new and innovative methods of health monitoring to emerge. Cuff-less and continuous methods of measuring blood pressure are particularly attractive as blood pressure is one of the most important measurements of long term cardiovascular health. Current methods of noninvasive blood pressure measurement are based on inflation and deflation of a cuff with some effects on arteries where blood pressure is being measured. This inflation can also cause patient discomfort and alter the measurement results. In this work, a mobile application was developed to collate the PhotoPlethysmoGramm (PPG) waveform provided by a pulse oximeter and the electrocardiogram (ECG) for calculating the pulse transit time. This information is then indirectly related to the user's systolic blood pressure. The developed application successfully connects to the PPG and ECG monitoring devices using Bluetooth wireless connection and stores the data onto an online server. The pulse transit time is estimated in real time and the user's systolic blood pressure can be estimated after the system has been calibrated. The synchronization between the two devices was found to pose a challenge to this method of continuous blood pressure monitoring. However, the implemented continuous blood pressure monitoring system effectively serves as a proof of concept. This combined with the massive benefits that an accurate and robust continuous blood pressure monitoring system would provide indicates that it is certainly worthwhile to further develop this system.

  10. Comparison of axial and radial electron beam-breakup transit-time oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, T.J.T. [Los Alamos National Lab., NM (United States); Mostrom, M.A. [Mission Research Corporation, Albuquerque, NM (United States)

    1995-08-01

    Comparison of two configurations of a novel high-power microwave generator is presented in this article. Coupling the beam-breakup instability with the transit-time effect of the electron beam in the cavity, rapid energy exchange between the electrons and cavity modes can occur. The dominant cavity modes in the axial and radial configurations are different but their growth rates are comparable. We found that the radial configuration can have a beam impedance less than 10 {Omega} and therefore more suitable for low-voltage and high power operation. Good agreements have been obtained between linear theory and simulation for both configurations.

  11. Modelling of transit-time ultrasonic flow meters under multi-phase flow conditions

    DEFF Research Database (Denmark)

    Simurda, Matej; Duggen, Lars; Lassen, Benny

    2016-01-01

    A pseudospectral model for transit time ultrasonic flowmeters under multiphase flow conditions is presented. The method solves first order stress-velocity equations of elastodynamics, with acoustic media being modelled by setting shear modulus to zero. Additional terms to account for the effect...... of the background flow are included. Spatial derivatives are calculated by a Fourier collocation scheme allowing the use of the Fast Fourier transform. The method is compared against analytical solutions and experimental measurements. Additionally, a study of clamp-on and in-line ultrasonic flowmeters operating...

  12. Historical Memory and Transitional Justice in Spain: the Time as Actor of Criminal Justice

    Directory of Open Access Journals (Sweden)

    Josep Tamarit Sumalla

    2014-10-01

    Full Text Available The article addresses the political, criminal and legal challenges posed by accountability demands for past crimes by studying the singularities that the Spanish transition from Franco’s dictatorship to democracy has raised. Especially, it is analysed the Historical Memory Law of 2007 and the most problematic points of the criminal justice actions that have emerged due to offenses committed during the dictatorship. Despite the existence of international crimes, the elapsed time has brought difficult to overcome, factual and legal difficulties for effective prosecution. This problem, focusing on the prohibition of retroactivity, prescription and effects of the Amnesty Act of 1977 is examined here.

  13. GaN based transfer electron and avalanche transit time devices

    Institute of Scientific and Technical Information of China (English)

    R.K.Parida; A.K.Panda

    2012-01-01

    A new model is developed to study the microwave/mm wave characteristics of two-terminal GaN- based transfer electron devices (TEDs),namely a Gunn diode and an impact avalanche transit time (IMPATT) device.Microwave characteristics such as device efficiency and the microwave power generated are computed and compared at D-band (140 GHz center frequency) to see the potentiality of each device under the same operating conditions.It is seen that GaN-based IMPATT devices surpass the Gunn diode in the said frequency region.

  14. GaN based transfer electron and avalanche transit time devices

    Science.gov (United States)

    Parida, R. K.; Panda, A. K.

    2012-05-01

    A new model is developed to study the microwave/mm wave characteristics of two-terminal GaN-based transfer electron devices (TEDs), namely a Gunn diode and an impact avalanche transit time (IMPATT) device. Microwave characteristics such as device efficiency and the microwave power generated are computed and compared at D-band (140 GHz center frequency) to see the potentiality of each device under the same operating conditions. It is seen that GaN-based IMPATT devices surpass the Gunn diode in the said frequency region.

  15. An Investigation of Pulse Transit Time as a Non-Invasive Blood Pressure Measurement Method

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, B M; O' Flynn, B; Mathewson, A, E-mail: brian.mccarthy@tyndall.ie [Tyndall National Institute, UCC, Lee Maltings, Prospect Row, Cork (Ireland)

    2011-08-17

    The objective of this paper is to examine the Pulse Transit Method (PTT) as a non-invasive means to track Blood Pressure over a short period of time. PTT was measured as the time it takes for an ECG R-wave to propagate to the finger, where it is detected by a photoplethysmograph sensor. The PTT method is ideal for continuous 24-hour Blood Pressure Measurement (BPM) since it is both cuff-less and non-invasive and therefore comfortable and unobtrusive for the patient. Other techniques, such as the oscillometric method, have shown to be accurate and reliable but require a cuff for operation, making them unsuitable for long term monitoring. Although a relatively new technique, the PTT method has shown to be able to accurately track blood pressure changes over short periods of time, after which re-calibration is necessary. The purpose of this study is to determine the accuracy of the method.

  16. Search for Time-Independent Lorentz Violation using Muon Neutrino to Muon Antineutrino Transitions in MINOS

    Energy Technology Data Exchange (ETDEWEB)

    Adamson, P.; et al.

    2016-05-10

    Data from the MINOS experiment has been used to search for mixing between muon neutrinos and muon antineutrinos using a time-independent Lorentz-violating formalism derived from the Standard-Model Extension (SME). MINOS is uniquely capable of searching for muon neutrino-antineutrino mixing given its long baseline and ability to distinguish between neutrinos and antineutrinos on an event-by-event basis. Neutrino and antineutrino interactions were observed in the MINOS Near and Far Detectors from an exposure of 10.56$\\times10^{20}$ protons-on-target from the NuMI neutrino-optimized beam. No evidence was found for such transitions and new, highly stringent limits were placed on the SME coefficients governing them. We place the first limits on the SME parameters $(c_{L})^{TT}_{\\mu\\mu} $ and $(c_{L})^{TT}_{\\tau\\tau}$ at $-8.4\\times10^{-23} < (c_{L})^{TT}_{\\mu\\mu} < 8.0\\times10^{-23}$ and $-8.0\\times10^{-23} < (c_{L})^{TT}_{\\tau\\tau} < 8.4\\times10^{-23}$, and the world's best limits on the $\\tilde{g}^{ZT}_{\\mu\\overline{\\mu}}$ and $\\tilde{g}^{ZT}_{\\tau\\overline{\\tau}}$ parameters at $|\\tilde{g}^{ZT}_{\\mu\\overline{\\mu}}| < 3.3\\times 10^{-23}$ and $|\\tilde{g}^{ZT}_{\\tau\\overline{\\tau}}| < 3.3\\times 10^{-23}$, all limits quoted at $3\\sigma$.

  17. Transit times of water particles in the vadose zone across catchment states and catchments functional units

    Science.gov (United States)

    Sprenger, Matthias; Weiler, Markus

    2014-05-01

    Understanding the water movement in the vadose zone and its associated transport of solutes are of major interest to reduce nutrient leaching, pollution transport or other risks to water quality. Soil physical models are widely used to asses such transport processes, while the site specific parameterization of these models remains challenging. Inverse modeling is a common method to adjust the soil physical parameters in a way that the observed water movement or soil water dynamics are reproduced by the simulation. We have shown that the pore water stable isotope concentration can serve as an additional fitting target to simulate the solute transport and water balance in the unsaturated zone. In the presented study, the Mualem- van Genuchten parameters for the Richards equation and diffusivity parameter for the convection-dispersion equation have been parameterized using the inverse model approach with Hydrus-1D for 46 experimental sites of different land use, topography, pedology and geology in the Attert basin in Luxembourg. With the best parameter set we simulated the transport of a conservative solute that was introduced via a pulse input at different points in time. Thus, the transit times in the upper 2 m of the soil for different catchment states could be inferred for each location. It has been shown that the time a particle needs to pass the -2 m depth plane highly varies from the systems state and the systems forcing during and after infiltration of that particle. Differences in transit times among the study sites within the Attert basin were investigated with regards to its governing factors to test the concept of functional units. The study shows the potential of pore water stable isotope concentration for residence times and transport analyses in the unsaturated zone leading to a better understanding of the time variable subsurface processes across the catchment.

  18. Direct simulation of groundwater transit-time distributions using the reservoir theory

    Science.gov (United States)

    Etcheverry, David; Perrochet, Pierre

    Groundwater transit times are of interest for the management of water resources, assessment of pollution from non-point sources, and quantitative dating of groundwaters by the use of environmental isotopes. The age of water is the time water has spent in an aquifer since it has entered the system, whereas the transit time is the age of water as it exits the system. Water at the outlet of an aquifer is a mixture of water elements with different transit times, as a consequence of the different flow-line lengths. In this paper, transit-time distributions are calculated by coupling two existing methods, the reservoir theory and a recent age-simulation method. Based on the derivation of the cumulative age distribution over the whole domain, the approach accounts for the whole hydrogeological framework. The method is tested using an analytical example and its applicability illustrated for a regional layered aquifer. Results show the asymmetry and multimodality of the transit-time distribution even in advection-only conditions, due to the aquifer geometry and to the velocity-field heterogeneity. Résumé Les temps de transit des eaux souterraines sont intéressants à connaître pour gérer l'évaluation des ressources en eau dans le cas de pollution à partir de sources non ponctuelles, et aussi pour dater quantitativement les eaux souterraines au moyen des isotopes du milieu. L'âge de l'eau est le temps qu'elle a passé dans un aquifère depuis qu'elle est entrée dans le système, alors que le temps de transit est l'âge de l'eau au moment où elle quitte le système. L'eau à la sortie d'un aquifère est un mélange d'eaux possédant différents temps de transit, du fait des longueurs différentes des lignes de courant suivies. Dans ce papier, les distributions des temps de transit sont calculées en couplant deux méthodes, la théorie du réservoir et une méthode récente de simulation des âges. Basée sur la dérivation de la distribution cumulées des âges sur

  19. 1,25(OH)2D3 attenuates TGF-β1/β2-induced increased migration and invasion via inhibiting epithelial–mesenchymal transition in colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shanwen; Zhu, Jing; Zuo, Shuai; Ma, Ju; Zhang, Junling; Chen, Guowei; Wang, Xin; Pan, Yisheng; Liu, Yucun; Wang, Pengyuan, E-mail: wangpengyuan2014@126.com

    2015-12-04

    1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) has been reported to inhibit proliferation and migration of multiple types of cancer cells. However, the mechanism underlying its anti-metastasis effect is not fully illustrated. In this study, the effect of 1,25(OH)2D3 on TGF-β1/β2-induced epithelial–mesenchymal transition (EMT) is tested in colon cancer cells. The results suggest that 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased invasion and migration of in SW-480 and HT-29 cells. 1,25(OH)2D3 also inhibited the cadherin switch in SW-480 and HT-29 cells. TGF-β1/β2-induced increased expression of EMT-related transcription factors was also inhibited by 1,25(OH)2D3. 1,25(OH)2D3 also inhibited the secretion of MMP-2 and MMP-9 and increased expression of F-actin induced by TGF-β1/β2 in SW-480 cells. Taken together, this study suggests that the suppression of EMT might be one of the mechanisms underlying the anti-metastasis effect of 1,25(OH)2D3 in colon cancer cells. - Highlights: • TGF-β1/β2-induced model of EMT was used in this study to test the effect of 1,25(OH)2D3 on EMT in colon cancer cells. • 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased migration and invasion. • 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased level of EMT-related transcription factors. • 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased expression of F-actin in SW-480 cells.

  20. Spheroid cells derived from human colon cancer cells exhibit epithelial to mesenchymal transition characteristics%悬浮培养结肠癌细胞球具有上皮间质转化特征

    Institute of Scientific and Technical Information of China (English)

    冷政伟; 尹碧辉; 李勇; 谭俊; 岳中屹; 陈锦皇; 奚海林; 陶凯雄; 夏清华

    2013-01-01

    目的 无血清悬浮培养人结肠癌DLD-1细胞形成细胞球,检测其肿瘤干细胞标志表达变化,并探讨球细胞发生上皮间质转化与肿瘤干细胞及肿瘤恶性行为之间的联系.方法 在添加生长因子的无血清培养基中培养DLD-1细胞形成球细胞,运用Transwell实验检测细胞的迁移、侵袭能力变化;裸鼠皮下成瘤和软琼脂克隆形成实验分别检测体内外成瘤能力变化;流式细胞术检测细胞中CD133表达变化;实时定量聚合酶链反应(Real-time PCR),Western blot检测CD133、CD166、富含亮氨酸重复序列G-蛋白偶联受体5(Lgr5)及上皮间质转化关键基因表达变化.结果 球细胞中CD133+细胞明显增加[(0.90±0.03)%比(2.70±0.35)%,P <0.05];高表达肿瘤干细胞标志CD133、CD166、Lgr5和间质分子波形蛋白(Vimentin)及Snail而低表达上皮细胞标志ZO-1(P<0.05).球细胞的转移、侵袭、体内外成瘤能力明显增加(P<0.05).结论 虽然黏钙蛋白(E-cadherin)表达明显升高,但是结合体内外实验结果,我们认为:E-cadherin可能不是介导细胞恶性行为的独立因素,悬浮培养形成的结肠癌球细胞已发生上皮间质转化,表现出肿瘤干细胞的特征.%Objective To investigate the similarities between cancer stem cells and epithelial mesenchymal transition (EMT) cells in spheroid cells.Methods Generate cancer spheroid cells from colon cancer cell line DLD-1 in serum free medium (SFM) and to investigate the expression of colon cancer stem cells markers such as CD133,CD166,leucine-rich-repeat-containing G-protein-coupled receptor 5 (Lgr5)and the numbers of CD133 + cells.In addition,the capacity of migration,invasion and tumorigenicity in vivo and in vitro were confirmed by transwell assay,colony formation assay and mouse xenograft model respectively.Moreover,the expression of EMT-related genes was detected by real-time quantitative polymerase chain reaction (Real-time PCR) and Western

  1. Insights into the water mean transit time in a high-elevation tropical ecosystem

    Science.gov (United States)

    Mosquera, Giovanny M.; Segura, Catalina; Vaché, Kellie B.; Windhorst, David; Breuer, Lutz; Crespo, Patricio

    2016-07-01

    This study focuses on the investigation of the mean transit time (MTT) of water and its spatial variability in a tropical high-elevation ecosystem (wet Andean páramo). The study site is the Zhurucay River Ecohydrological Observatory (7.53 km2) located in southern Ecuador. A lumped parameter model considering five transit time distribution (TTD) functions was used to estimate MTTs under steady-state conditions (i.e., baseflow MTT). We used a unique data set of the δ18O isotopic composition of rainfall and streamflow water samples collected for 3 years (May 2011 to May 2014) in a nested monitoring system of streams. Linear regression between MTT and landscape (soil and vegetation cover, geology, and topography) and hydrometric (runoff coefficient and specific discharge rates) variables was used to explore controls on MTT variability, as well as mean electrical conductivity (MEC) as a possible proxy for MTT. Results revealed that the exponential TTD function best describes the hydrology of the site, indicating a relatively simple transition from rainfall water to the streams through the organic horizon of the wet páramo soils. MTT of the streams is relatively short (0.15-0.73 years, 53-264 days). Regression analysis revealed a negative correlation between the catchment's average slope and MTT (R2 = 0.78, p < 0.05). MTT showed no significant correlation with hydrometric variables, whereas MEC increases with MTT (R2 = 0.89, p < 0.001). Overall, we conclude that (1) baseflow MTT confirms that the hydrology of the ecosystem is dominated by shallow subsurface flow; (2) the interplay between the high storage capacity of the wet páramo soils and the slope of the catchments provides the ecosystem with high regulation capacity; and (3) MEC is an efficient predictor of MTT variability in this system of catchments with relatively homogeneous geology.

  2. Transit Timing Observations from Kepler: II. Confirmation of Two Multiplanet Systems via a Non-parametric Correlation Analysis

    CERN Document Server

    Ford, Eric B; Steffen, Jason H; Carter, Joshua A; Fressin, Francois; Holman, Matthew J; Lissauer, Jack J; Moorhead, Althea V; Morehead, Robert C; Ragozzine, Darin; Rowe, Jason F; Welsh, William F; Allen, Christopher; Batalha, Natalie M; Borucki, William J; Bryson, Stephen T; Buchhave, Lars A; Burke, Christopher J; Caldwell, Douglas A; Charbonneau, David; Clarke, Bruce D; Cochran, William D; Désert, Jean-Michel; Endl, Michael; Everett, Mark E; Fischer, Debra A; Gautier, Thomas N; Gilliland, Ron L; Jenkins, Jon M; Haas, Michael R; Horch, Elliott; Howell, Steve B; Ibrahim, Khadeejah A; Isaacson, Howard; Koch, David G; Latham, David W; Li, Jie; Lucas, Philip; MacQueen, Phillip J; Marcy, Geoffrey W; McCauliff, Sean; Mullally, Fergal R; Quinn, Samuel N; Quintana, Elisa; Shporer, Avi; Still, Martin; Tenenbaum, Peter; Thompson, Susan E; Torres, Guillermo; Twicken, Joseph D; Wohler, Bill

    2012-01-01

    We present a new method for confirming transiting planets based on the combination of transit timingn variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies are in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data sets. We apply this method to an analysis of the transit timing variations of two stars with multiple transiting planet candidates identified by Kepler. We confirm four transiting planets in two multiple planet systems based on their TTVs and the constraints imposed by dynamical stability. An additional three candidates in these same systems are not confirmed as planets, but are likely to be validated as real planets once further observations and analyses are possible. If all were confirmed, these systems would be near 4:6:...

  3. Second-order Transit Time Factors for a Two Gap Resonator

    CERN Document Server

    Fraser, MA

    2009-01-01

    The HIE-ISOLDE linac at CERN will operate independently phased quarter-wave resonators (QWRs) in order to accelerate radioactive ion beams (RIBs), with mass to charge states in the range 2.5 < A/q < 4.5, from 1.2 MeV/u up to an energy of at least 10 MeV/u. The low-β version of the QWR will also be used to decelerate beams below 1.2 MeV/u. The combination of low velocity and high gradient results in a significant change of the ion velocity and a breakdown of the first-order approximation commonly used to calculate the energy gain in accelerating cavities. The first-order transit-time factor for two gaps is briefly reviewed before higher-order transit-time factors are derived and the energy gain expressed, taking into account the variation in velocity, to second-order. The formalism of J.R. Delayen, introduced in [1], is used throughout.

  4. Effects of anatomical position on esophageal transit time: A biomagnetic diagnostic technique

    Institute of Scientific and Technical Information of China (English)

    Teodoro Cordova-Fraga; Modesto Sosa; Cados Wiechers; Jose Maria De la Roca-Chiapas; Alejandro Maldonado Moreles; Jesus BernaI-Alvarado; Raquel Huerta-Franco

    2008-01-01

    AIM: To study the esophageal transit time (ETT)and compare its mean value among three anatomical inclinations of the body; and to analyze the correlation of ETT to body mass index (BMI).METHODS: A biomagnetic technique was implemented to perform this study: (1) The transit time of a magnetic marker (MM) through the esophagus was measured using two fluxgate sensors placed over the chest of 14 healthy subjects; (2) the ETT was assessed in three anatomical positions (at upright,fowler,and supine positions; 90°,45° and 0°,respectively).RESULTS: ANOVA and Tuckey post-hoc tests demonstrated significant differences between ETT mean of the different positions.The ETT means were 5.2 ±1.1 s,6.1±1.5 s,and 23.6 ± 9.2 s for 90°,45° and 0°,respectively.Pearson correlation results were r = -0.716 and P < 0.001 by subjects' anatomical position,and r =-0.024 and P > 0.05 according the subject's BHI.CONCLUSION: We demonstrated that using this biomagnetic technique,it is possible to measure the ETT and the effects of the anatomical position on the ETT.

  5. Examining the Effects of Geomorphology on Hydrologic Transit Times Using Liquid Water Isotopes

    Science.gov (United States)

    Delgado, D.; Troch, P.; Lyon, S.; Desilets, S.; Guardiola, M.; Broxton, P.

    2007-12-01

    In recent years there has been resurgence in improving physically based and spatially distributed hydrological response models. However there continues to be many obstacles in accurately representing the basic processes governing rainfall runoff responses. Much of these inaccuracies can be attributed to such problems as a lack of understanding in runoff processes, unknown heterogeneity both at the surface and subsurface, variations in driving forces and the effects of geomorphology on the transformation of rainfall to stream flow. We hope to improve on such ambiguity is by examining the relationships between geomorphology and hydrology through the investigation of transit time distributions, which can be used as a fundamental descriptor of catchments" characteristics such as storage and flow pathways. By examining stable isotopic variability in precipitation, soil moisture and stream flow to determine transit times, we hope to better understand the effects of topographic land structures on the hydrologic response system. The first step in this process has been to fully instrument a series of hill slopes with similar structural and pedologic characteristics, located in the Marshall Gulch region of the Santa Catalina Mountains. Equipment including suction and non- suction lysimeters, tipping bucket rain gauges and automatic flow samplers with data loggers positioned to take stream flow and precipitation samples have been used to collect samples throughout the region. A description of preliminary results will be presented.

  6. TASTE. III. A homogeneous study of transit time variations in WASP-3b

    CERN Document Server

    Nascimbeni, V; Murabito, S; Sada, P V; Aparicio, A; Piotto, G; Bedin, L R; Milone, A P; Rosenberg, A; Borsato, L; Damasso, M; Granata, V; Malavolta, L

    2012-01-01

    The TASTE project is searching for low-mass planets with the Transit Timing Variation (TTV) technique, by gathering high-precision, short-cadence light curves for a selected sample of transiting exoplanets. It has been claimed that the "hot Jupiter" WASP-3b could be perturbed by a second planet. Presenting eleven new light curves (secured at the IAC80 and UDEM telescopes) and re-analyzing thirty-eight archival light curves in a homogeneous way, we show that new data do not confirm the previously claimed TTV signal. However, we bring evidence that measurements are not consistent with a constant orbital period, though no significant periodicity can be detected. Additional dynamical modeling and follow-up observations are planned to constrain the properties of the perturber or to put upper limits to it. We provide a refined ephemeris for WASP-3b and improved orbital/physical parameters. A contact eclipsing binary, serendipitously discovered among field stars, is reported here for the first time.

  7. Pulse transit time variability analysis in an animal model of endotoxic shock.

    Science.gov (United States)

    Tang, Collin H H; Chan, Gregory S H; Middleton, Paul M; Cave, Grant; Harvey, Martyn; Javed, Faizan; Savkin, Andrey V; Lovell, Nigel H

    2010-01-01

    The use of non-invasively measured pulse transit time (PTT) to monitor the cardiovascular systems in critically ill patients, like sepsis, can be of significant clinical value. In this study, the potential of PTT and its variability in cardiovascular system monitoring in a mechanically ventilated and anesthetized rabbit model of endotoxic shock was assessed. Eight adult New Zealand white rabbits, which were treated with endotoxin bolus infusion, were studied. Measurements of PTT, pre-ejection period (PEP), and vascular transit time (VTT) were obtained in pre- and post-intervention stages (before and 90 minutes after the administration of endotoxin). The decrease in mean PTT (p VTT (p VTT (R(2) ≥ 0.84 with positive slope). Computation of coherence and phase shift in the ventilating frequency band (HF: 0.50 - 0.75 Hz) showed that the respiratory variation in PTT was synchronized with both PEP and VTT (coherence > 0.84 with phase shift less than one cardiac beat). These results highlighted the potential value of PTT and its respiratory variation in characterizing the pathophysioloigcal hemodynamic change in endotoxic shock.

  8. Detection of Laplace-resonant three-planet systems from transit timing variations

    CERN Document Server

    Libert, A -S

    2013-01-01

    Transit timing variations (TTVs) are useful to constrain the existence of perturbing planets, especially in resonant systems where the variations are strongly enhanced. Here we focus on Laplace-resonant three-planet systems, and assume the inner planet transits the star. A dynamical study is performed for different masses of the three bodies, with a special attention to terrestrial planets. We consider a maximal time-span of ~ 100 years and discuss the shape of the inner planet TTVs curve. Using frequency analysis, we highlight the three periods related to the evolution of the system: two periods associated with the Laplace-resonant angle and the third one with the precession of the pericenters. These three periods are clearly detected in the TTVs of an inner giant planet perturbed by two terrestrial companions. Only two periods are detected for a Jupiter-Jupiter-Earth configuration (the ones associated with the giant interactions) or for three terrestrial planets (the Laplace periods). However, the latter sy...

  9. 1,25(OH)2D3 attenuates TGF-β1/β2-induced increased migration and invasion via inhibiting epithelial-mesenchymal transition in colon cancer cells.

    Science.gov (United States)

    Chen, Shanwen; Zhu, Jing; Zuo, Shuai; Ma, Ju; Zhang, Junling; Chen, Guowei; Wang, Xin; Pan, Yisheng; Liu, Yucun; Wang, Pengyuan

    1,25-Dihydroxyvitamin D3 (1,25(OH)2D3) has been reported to inhibit proliferation and migration of multiple types of cancer cells. However, the mechanism underlying its anti-metastasis effect is not fully illustrated. In this study, the effect of 1,25(OH)2D3 on TGF-β1/β2-induced epithelial-mesenchymal transition (EMT) is tested in colon cancer cells. The results suggest that 1,25(OH)2D3 inhibited TGF-β1/β2-induced increased invasion and migration of in SW-480 and HT-29 cells. 1,25(OH)2D3 also inhibited the cadherin switch in SW-480 and HT-29 cells. TGF-β1/β2-induced increased expression of EMT-related transcription factors was also inhibited by 1,25(OH)2D3. 1,25(OH)2D3 also inhibited the secretion of MMP-2 and MMP-9 and increased expression of F-actin induced by TGF-β1/β2 in SW-480 cells. Taken together, this study suggests that the suppression of EMT might be one of the mechanisms underlying the anti-metastasis effect of 1,25(OH)2D3 in colon cancer cells.

  10. Sport Transition of JPSS VIIRS Imagery for Night-time Applications

    Science.gov (United States)

    Fuell, Kevin; LeRoy, Anita; Smith, Matt; Miller, Steve; Kann, Diedre; Bernhardt, David; Reydell, Nezette; Cox, Robert

    2014-01-01

    The NASA/Short-term Prediction, Research, and Transition (SPoRT) Program and NOAA/Cooperative Institute for Research in the Atmosphere (CIRA) work within the NOAA/Joint Polar Satellite System (JPSS) Proving Ground to demonstrate the unique capabilities of the VIIRS instrument. Very similar to MODIS, the VIIRS instrument provides many high-resolution visible and infrared channels in a broad spectrum. In addition, VIIRS is equipped with a low-light sensor that is able to detect light emissions from the land and atmosphere as well as reflected sunlight by the lunar surface. This band is referred to as the Day-Night Band due to the sunlight being used at night to see cloud and topographic features just as one would typically see in day-time visible imagery. NWS forecast offices that collaborate with SPoRT and CIRA have utilized MODIS imagery in operations, but have longed for more frequent passes of polar-orbiting data. The VIIRS instrument enhances SPoRT collaborations with WFOs by providing another day and night-time pass, and at times two additional passes due to its large swath width. This means that multi-spectral, RGB imagery composites are more readily available to prepare users for their use in GOES-R era and high-resolution imagery for use in high-latitudes is more frequently able to supplement standard GOES imagery within the SPoRT Hybrid GEO-LEO product. The transition of VIIRS also introduces the new Day-Night Band capability to forecast operations. An Intensive Evaluation Period (IEP) was conducted in Summer 2013 with a group of "Front Range" NWS offices related to VIIRS night-time imagery. VIIRS single-channel imagery is able to better analyze the specific location of fire hotspots and other land features, as well as provide a more true measurement of various cloud and aerosol properties than geostationary measurements, especially at night. Viewed within the SPoRT Hybrid imagery, the VIIRS data allows forecasters to better interpret the more frequent, but

  11. Search for time-independent Lorentz violation using muon neutrino to muon antineutrino transitions in MINOS

    CERN Document Server

    Adamson, P; Aurisano, A; Barr, G; Bishai, M; Blake, A; Bock, G J; Bogert, D; Cao, S V; Carroll, T J; Castromonte, C M; Chen, R; Childress, S; Coelho, J A B; Corwin, L; Cronin-Hennessy, D; de Jong, J K; de Rijck, S; Devan, A V; Devenish, N E; Diwan, M V; Escobar, C O; Evans, J J; Falk, E; Feldman, G J; Flanagan, W; Frohne, M V; Gabrielyan, M; Gallagher, H R; Germani, S; Gomes, R A; Goodman, M C; Gouffon, P; Graf, N; Gran, R; Grzelak, K; Habig, A; Hahn, S R; Hartnell, J; Hatcher, R; Holin, A; Huang, J; Hylen, J; Irwin, G M; Isvan, Z; James, C; Jensen, D; Kafka, T; Kasahara, S M S; Koizumi, G; Kordosky, M; Kreymer, A; Lang, K; Ling, J; Litchfield, P J; Lucas, P; Mann, W A; Marshak, M L; Mayer, N; McGivern, C; Medeiros, M M; Mehdiyev, R; Meier, J R; Messier, M D; Miller, W H; Mishra, S R; Sher, S Moed; Moore, C D; Mualem, L; Musser, J; Naples, D; Nelson, J K; Newman, H B; Nichol, R J; Nowak, J A; O'Connor, J; Orchanian, M; Pahlka, R B; Paley, J; Patterson, R B; Pawloski, G; Perch, A; Pfützner, M M; Phan, D D; Phan-Budd, S; Plunkett, R K; Poonthottathil, N; Qiu, X; Radovic, A; Rebel, B; Rosenfeld, C; Rubin, H A; Sail, P; Sanchez, M C; Schneps, J; Schreckenberger, A; Schreiner, P; Sharma, R; Sousa, A; Tagg, N; Talaga, R L; Thomas, J; Thomson, M A; Tian, X; Timmons, A; Todd, J; Tognini, S C; Toner, R; Torretta, D; Tzanakos, G; Urheim, J; Vahle, P; Viren, B; Weber, A; Webb, R C; White, C; Whitehead, L; Whitehead, L H; Wojcicki, S G; Zwaska, R

    2016-01-01

    Data from the MINOS experiment has been used to search for mixing between muon neutrinos and muon antineutrinos using a time-independent Lorentz-violating formalism derived from the Standard-Model Extension (SME). MINOS is uniquely capable of searching for muon neutrino-antineutrino mixing given its long baseline and ability to distinguish between neutrinos and antineutrinos on an event-by-event basis. Neutrino and antineutrino interactions were observed in the MINOS Near and Far Detectors from an exposure of 10.56$\\times10^{20}$ protons-on-target from the NuMI neutrino-optimized beam. No evidence was found for such transitions and new, highly stringent limits were placed on the SME coefficients governing them. We place the first limits on the SME parameters $(c_{L})^{TT}_{\\mu\\mu} $ and $(c_{L})^{TT}_{\\tau\\tau}$ at $-8.4\\times10^{-23} < (c_{L})^{TT}_{\\mu\\mu} < 8.0\\times10^{-23}$ and $-8.0\\times10^{-23} < (c_{L})^{TT}_{\\tau\\tau} < 8.4\\times10^{-23}$, and the world's best limits on the $\\tilde{g}^{Z...

  12. Spectral analysis of finite-time correlation matrices near equilibrium phase transitions

    Science.gov (United States)

    Vinayak; Prosen, T.; Buča, B.; Seligman, T. H.

    2014-10-01

    We study spectral densities for systems on lattices, which, at a phase transition display, power-law spatial correlations. Constructing the spatial correlation matrix we prove that its eigenvalue density shows a power law that can be derived from the spatial correlations. In practice time series are short in the sense that they are either not stationary over long time intervals or not available over long time intervals. Also we usually do not have time series for all variables available. We shall make numerical simulations on a two-dimensional Ising model with the usual Metropolis algorithm as time evolution. Using all spins on a grid with periodic boundary conditions we find a power law, that is, for large grids, compatible with the analytic result. We still find a power law even if we choose a fairly small subset of grid points at random. The exponents of the power laws will be smaller under such circumstances. For very short time series leading to singular correlation matrices we use a recently developed technique to lift the degeneracy at zero in the spectrum and find a significant signature of critical behavior even in this case as compared to high temperature results which tend to those of random matrix models.

  13. Extended Coherence Time on the Clock Transition of Optically Trapped Rubidium

    DEFF Research Database (Denmark)

    Kleine Büning, G.; Will, J.; Ertmer, W.

    2011-01-01

    Optically trapped ensembles are of crucial importance for frequency measurements and quantum memories but generally suffer from strong dephasing due to inhomogeneous density and light shifts. We demonstrate a drastic increase of the coherence time to 21 s on the magnetic field insensitive clock...... transition of 87Rb by applying the recently discovered spin self-rephasing [C. Deutsch et al., Phys. Rev. Lett. 105, 020401 (2010)]. This result confirms the general nature of this new mechanism and thus shows its applicability in atom clocks and quantum memories. A systematic investigation of all relevant...... frequency shifts and noise contributions yields a stability of 2.4×10-11τ-1/2, where τ is the integration time in seconds. Based on a set of technical improvements, the presented frequency standard is predicted to rival the stability of microwave fountain clocks in a potentially much more compact setup....

  14. The η transition form factor from space- and time-like experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Escribano, R. [Universitat Autonoma de Barcelona, Departament de Fisica, Grup de Fisica Teorica, and Institut de Fisica d' Altes Energies (IFAE), Bellaterra, Barcelona (Spain); Masjuan, P.; Sanchez-Puertas, P. [Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Institut fuer Kernphysik, Mainz (Germany)

    2015-09-15

    The η transition form factor is analyzed for the first time in both space- and time-like regions at low and intermediate energies in a model-independent approach through the use of rational approximants. The η @→ e{sup +}e{sup -}γ experimental data provided by the A2 Collaboration in the very low energy region of the dielectron invariant mass distribution allows for the extraction of the most precise up-to-date slope and curvature parameters of the form factors as well as their values at zero and infinity. The impact of these new results on the mixing parameters of the η-η' system, together with the role played by renormalization dependent effects, and on the determination of the V Pγ couplings from V @→ Pγ and P → Vγ radiative decays is also discussed. (orig.)

  15. The η transition form factor from space- and time-like experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Escribano, R., E-mail: rescriba@ifae.es [Departament de Física, Grup de Física Teòrica, and Institut de Física d’Altes Energies (IFAE), Universitat Autònoma de Barcelona, 08193, Bellaterra, Barcelona (Spain); Masjuan, P., E-mail: masjuan@kph.uni-mainz.de; Sanchez-Puertas, P., E-mail: sanchezp@kph.uni-mainz.de [PRISMA Cluster of Excellence, Institut für Kernphysik, Johannes Gutenberg-Universität, 55099, Mainz (Germany)

    2015-09-09

    The η transition form factor is analyzed for the first time in both space- and time-like regions at low and intermediate energies in a model-independent approach through the use of rational approximants. The η→e{sup +}e{sup -}γ experimental data provided by the A2 Collaboration in the very low-energy region of the dielectron invariant mass distribution allows for the extraction of the most precise up-to-date slope and curvature parameters of the form factors as well as their values at zero and infinity. The impact of these new results on the mixing parameters of the η–η{sup ′} system, together with the role played by renormalization dependent effects, and on the determination of the VPγ couplings from V→Pγ and P→Vγ radiative decays is also discussed.

  16. Short-time Lyapunov exponent analysis and the transition to chaos in Taylor-Couette flow

    Science.gov (United States)

    Vastano, John A.; Moser, Robert D.

    1991-01-01

    The physical mechanism driving the weakly chaotic Taylor-Couette flow is investigated using the short-time Liapunov exponent analysis. In this procedure, the transition from quasi-periodicity to chaos is studied using direct numerical 3D simulations of axially periodic Taylor-Couette flow, and a partial Liapunov exponent spectrum for the flow is computed by simultaneously advancing the full solution and a set of perturbations. It is shown that the short-time Liapunov exponent analysis yields more information on the exponents and dimension than that obtained from the common Liapunov exponent calculations. Results show that the chaotic state studied here is caused by a Kelvin-Helmholtz-type instability of the outflow boundary jet of Taylor vortices.

  17. Cortical phase transitions, non-equilibrium thermodynamics and the time-dependent Ginzburg-Landau equation

    CERN Document Server

    Freeman, W J; Obinata, M; Vitiello, G

    2011-01-01

    The formation of amplitude modulated and phase modulated assemblies of neurons is observed in the brain functional activity. The study of the formation of such structures requires that the analysis has to be organized in hierarchical levels, microscopic, mesoscopic, macroscopic, each with its characteristic space-time scales and the various forms of energy, electric, chemical, thermal produced and used by the brain. In this paper, we discuss the microscopic dynamics underlying the mesoscopic and the macroscopic levels and focus our attention on the thermodynamics of the non-equilibrium phase transitions. We obtain the time-dependent Ginzburg-Landau equation for the non-stationary regime and consider the formation of topologically non-trivial structures such as the vortex solution. The power laws observed in functional activities of the brain is also discussed and related to coherent states characterizing the many-body dissipative model of brain.

  18. Phase transition and crossover in diffusion-limited aggregation with reaction times

    Science.gov (United States)

    Nagatani, Takashi; Stanley, H. Eugene

    1990-09-01

    A generalized diffusion-limited aggregation (DLA) with reaction times that has been proposed by Bunde and Miyazima [Phys. Rev. A 38, 2099 (1988)] is considered. Crossover from the DLA to the diffusion-limited self-avoiding walk (DLSAW) is investigated by using the two-parameter position-space renormalization-group method. The crossover exponent and the crossover radius are calculated. The geometrical phase transition between DLA and DLSAW found by Bunde and Miyajima is analyzed by making use of the three-parameter position-space renormalization-group method. A global flow diagram in the three-parameter space is obtained. Above the percolation threshold all the renormalization flows are merged into the DLA point. Below the threshold all the renormalization flows are merged into the DLSAW point. When the reaction time is large, the double-crossover phenomenon occurs below the threshold.

  19. Pulse wave transit time measured by imaging photoplethysmography in upper extremities

    Science.gov (United States)

    Volynsky, M. A.; Mamontov, O. V.; Sidorov, I. S.; Kamshilin, A. A.

    2016-08-01

    We describe highly reliable measurement method of the pulse wave transit time (PWTT) to human limbs by using simultaneous recordings of imaging photoplethysmography and electrocardiography. High accuracy of measurements was achieved by access to a larger number of statistically independent data obtained simultaneously in different points. The method is characterized by higher diagnostic reliability because of automatic selection of the regions less affected by environmental noise. The technique was tested in the group of 12 young healthy subjects aged from 21 to 33 years. Even though PWTT in right and left hands was comparable after averaging over the whole group of subjects, significant difference in the time delay of pulse wave between the hands was found in several individuals. The technique can be used for early-stage diagnostics of various vascular diseases.

  20. Short-time Lyapunov exponent analysis and the transition to chaos in Taylor-Couette flow

    Science.gov (United States)

    Vastano, John A.; Moser, Robert D.

    1991-01-01

    The physical mechanism driving the weakly chaotic Taylor-Couette flow is investigated using the short-time Liapunov exponent analysis. In this procedure, the transition from quasi-periodicity to chaos is studied using direct numerical 3D simulations of axially periodic Taylor-Couette flow, and a partial Liapunov exponent spectrum for the flow is computed by simultaneously advancing the full solution and a set of perturbations. It is shown that the short-time Liapunov exponent analysis yields more information on the exponents and dimension than that obtained from the common Liapunov exponent calculations. Results show that the chaotic state studied here is caused by a Kelvin-Helmholtz-type instability of the outflow boundary jet of Taylor vortices.

  1. Imaging of total colonic Hirschsprung disease

    Energy Technology Data Exchange (ETDEWEB)

    Stranzinger, Enno; DiPietro, Michael A.; Strouse, Peter J. [University of Michigan Health System, Section of Pediatric Radiology, Ann Arbor, MI (United States); Teitelbaum, Daniel H. [University of Michigan Health System, Section of Pediatric Surgery, Ann Arbor, MI (United States)

    2008-11-15

    Hirschsprung disease (HD) is a functional obstruction of the bowel caused by the absence of intrinsic enteric ganglion cells. The diagnosis of total colonic HD (TCHD) based on contrast enemas is difficult in newborns because radiological findings vary. To evaluate the radiographic and contrast enema findings in patients with pathologically proven TCHD. From 1966 to 2007, 17 records from a total of 31 patients with TCHD were retrospectively evaluated for diameter and shape of the colon, diameter of the small bowel, bowel wall contour, ileal reflux, abdominal calcifications, pneumoperitoneum, filling defects, transitional zones and rectosigmoid index. Three colonic patterns of TCHD were found: microcolon, question-mark-shape colon and normal caliber colon. Additional findings included spasmodic colon, ileal reflux, delayed evacuation and abdominal calcifications. Colonic transitional zones were found in eight patients with TCHD. The diagnosis of TCHD is difficult to establish by contrast enema studies. The length of the aganglionic small bowel and the age of the patient can influence the radiological findings in TCHD. The transitional zone and the rectosigmoid index can be false-positive in TCHD. The colon can appear normal. Consider TCHD if the contrast enema study is normal but the patient remains symptomatic and other causes of distal bowel obstruction have been excluded. (orig.)

  2. Understanding Flow Pathways, Mixing and Transit Times for Water Quality Modelling

    Science.gov (United States)

    Dunn, S. M.; Bacon, J. R.; Soulsby, C.; Tetzlaff, D.

    2007-12-01

    Water quality modelling requires representation of the physical processes controlling the movement of solutes and particulates at an appropriate level of detail to address the objective of the model simulations. To understand and develop mitigation strategies for diffuse pollution at catchment scales, it is necessary for models to be able to represent the sources and age of water reaching rivers at different times. Experimental and modelling studies undertaken on several catchments in the north east of Scotland have used natural hydrochemical and isotopic tracers as a means of obtaining spatially integrated information about mixing processes. Methods for obtaining and integrating appropriate data are considered together with the implications of neglecting it. The tracer data have been incorporated in a conceptual hydrological model to study the sensitivity of the modelled tracer response to factors that may not affect runoff simulations but do affect mixing and transit times of the water. Results from the studies have shown how model structural and parameter uncertainties can lead to errors in the representation of: the flow pathways of water; the degree to which these flow pathways have mixed and the length of time for which water has been stored within the soil / groundwater system. It has been found to be difficult to eliminate structural uncertainty regarding the mechanisms of mixing, and parameter uncertainty regarding the role of groundwater. Simulations of nitrate pollution, resulting from the application of agricultural fertilisers, have been undertaken to demonstrate the sensitivity of water quality simulations to the potential errors in physical transport mechanisms, inherent in models that fail to account correctly for flow pathways, mixing and transit times.

  3. Factors controlling inter-catchment variation of mean transit time with consideration of temporal variability

    Science.gov (United States)

    Ma, Wenchao; Yamanaka, Tsutomu

    2016-03-01

    The catchment transit time, a lumped descriptor reflecting both time scale and spatial structure of catchment hydrology can provide useful insights into chemical/nuclear pollution risks within a catchment. Despite its importance, factors controlling spatial variation of mean transit time (MTT) are not yet well understood. In this study, we estimated time-variant MTTs for about ten years (2003-2012) in five mesoscale sub-catchments of the Fuji River catchment, central Japan, to establish the factors controlling their inter-catchment variation with consideration of temporal variability. For this purpose, we employed a lumped hydrological model that was calibrated and validated by hydrometric and isotopic tracer observations. Temporal variation patterns of estimated MTT were similar in all sub-catchments, but with differing amplitudes. Inter-catchment variation of MTT was greater in dry periods than wet periods, suggesting spatial variation of MTT is controlled by water 'stock' rather than by 'flow'. Although the long-term average MTT (LAMTT) in each catchment was correlated with mean slope, coverage of forest (or conversely, other land use types), coverage of sand-shale conglomerate, and groundwater storage, the multiple linear regression revealed that inter-catchment variation of LAMTT is principally controlled by the amount of groundwater storage. This is smaller in mountainous areas covered mostly by forests and greater in plain areas with less forest coverage and smaller slope. This study highlights the topographic control of MTT via groundwater storage, which might be a more important factor in mesoscale catchments, including both mountains and plains, rather than in smaller catchments dominated by mountainous topography.

  4. Weighing Scale-Based Pulse Transit Time is a Superior Marker of Blood Pressure than Conventional Pulse Arrival Time

    Science.gov (United States)

    Martin, Stephanie L.-O.; Carek, Andrew M.; Kim, Chang-Sei; Ashouri, Hazar; Inan, Omer T.; Hahn, Jin-Oh; Mukkamala, Ramakrishna

    2016-12-01

    Pulse transit time (PTT) is being widely pursued for cuff-less blood pressure (BP) monitoring. Most efforts have employed the time delay between ECG and finger photoplethysmography (PPG) waveforms as a convenient surrogate of PTT. However, these conventional pulse arrival time (PAT) measurements include the pre-ejection period (PEP) and the time delay through small, muscular arteries and may thus be an unreliable marker of BP. We assessed a bathroom weighing scale-like system for convenient measurement of ballistocardiography and foot PPG waveforms – and thus PTT through larger, more elastic arteries – in terms of its ability to improve tracking of BP in individual subjects. We measured “scale PTT”, conventional PAT, and cuff BP in humans during interventions that increased BP but changed PEP and smooth muscle contraction differently. Scale PTT tracked the diastolic BP changes well, with correlation coefficient of ‑0.80 ± 0.02 (mean ± SE) and root-mean-squared-error of 7.6 ± 0.5 mmHg after a best-case calibration. Conventional PAT was significantly inferior in tracking these changes, with correlation coefficient of ‑0.60 ± 0.04 and root-mean-squared-error of 14.6 ± 1.5 mmHg (p < 0.05). Scale PTT also tracked the systolic BP changes better than conventional PAT but not to an acceptable level. With further development, scale PTT may permit reliable, convenient measurement of BP.

  5. Spin time-relaxation within strongly coupled paramagnetic systems exhibiting paramagnetic-ferrimagnetic transitions

    Energy Technology Data Exchange (ETDEWEB)

    Chahid, M.; Benhamou, M. E-mail: benhamou.mabrouk@caramail.com

    2000-08-01

    The purpose of the present work is a quantitative study of the spin time relaxation within superweak ferrimagnetic materials exhibiting a paramagnetic-ferrimagnetic transition, when the temperature is changed from an initial value T{sub i} to a final one T{sub f} very close to the critical temperature T{sub c}. From a magnetic point of view, the material under investigation is considered to be made of two strongly coupled paramagnetic sublattices of respective moments phi (cursive,open) Greek and {psi}. Calculations are made within a Landau mean-field theory, whose free energy involves, in addition to quadratic and quartic terms in both moments phi (cursive,open) Greek and {psi}, a lowest-order coupling - Cphi (cursive,open) Greek{psi}, where C<0 stands for the coupling constant measuring the interaction between the two sublattices. We first determine the time dependence of the shifts of the order parameters {delta}phi (cursive,open) Greek and {delta}{psi} from the equilibrium state. We find that this time dependence is completely controlled by two kinds of relaxation times {tau}{sub 1} and {tau}{sub 2}. The former is a long time and the second a short one, and they are associated, respectively, with long and local wavelength fluctuations. We find that, only the first relaxation time is relevant for physics, since it drives the system to undergo a phase transition. Spatial fluctuations are also taken into account. In this case, we find an explicit expression of the relaxation times, which are functions of temperature T, coupling constant C and wave vector q. We find that the critical mode is that given by the zero scattering-angle limit, i.e. q=0. Finally, we emphasize that the appearance of these two relaxation times is in good agreement with results reported in recent experimental work dealt with the Curie-Weiss paramagnet compound Li{sub x}Ni{sub 2-x}O{sub 2}, where the composition x is very close to 1.

  6. Dynamic contrast optical coherence tomography: quantitative measurement of microvascular transit-time distributions in vivo (Conference Presentation)

    Science.gov (United States)

    Merkle, Conrad W.; Srinivasan, Vivek J.

    2016-03-01

    Transit time is a fundamental microcirculatory parameter that is critical in determining oxygen delivery from capillaries to surrounding tissue. Recently, it was demonstrated theoretically that capillary transit-time heterogeneity potentially leads to non-uniform oxygen extraction in micro-domains. However, in spite of its importance, capillary transit-time distribution has been challenging to quantify comprehensively and efficiently at the microscopic level. Here, we introduce a method, called Dynamic Contrast Optical Coherence Tomography (DyC-OCT), based on dynamic cross-sectional OCT imaging of the kinetics of an intravascular tracer during its passage through the field-of-view. DyC-OCT is used to quantitatively measure the transit-time distribution in microvascular networks in cross-section at the single-capillary level. Transit-time metrics are derived from analysis of the temporal characteristics of the dynamic scattering signal, related to tracer concentration, using indicator-dilution theory. Since DyC-OCT does not require calibration of the optical focus, quantitative accuracy is achieved even deep in highly scattering brain tissue where the focal spot degrades. After direct validation of DyC-OCT against the dilution curves measured using a fluorescent plasma label in the surface pial vessels of a mouse brain, imaged through a thinned-skull, glass coverslip-reinforced cranial window, the laminar transit-time distribution was investigated in microvasculature across the entire depth of the mouse somatosensory cortex. Laminar trends were identified, with the earliest transit times in the middle cortical layers, and the lowest heterogeneity in cortical layer 4. The new DyC-OCT technique affords a novel perspective of microvascular networks, with the unique capability of performing simultaneous measurements of transit-time distributions across cortical laminae.

  7. Signal Transceiver Transit Times and Propagation Delay Corrections for Ranging and Georeferencing Applications

    Directory of Open Access Journals (Sweden)

    P. Kaufmann

    2012-01-01

    Full Text Available The accuracy of ranging measurements depends critically on the knowledge of time delays undergone by signals when retransmitted by a remote transponder and due to propagation effects. A new method determines these delays for every single pulsed signal transmission. It utilizes four ground-based reference stations, synchronized in time and installed at well-known geodesic coordinates and a repeater in space, carried by a satellite, balloon, aircraft, and so forth. Signal transmitted by one of the reference bases is retransmitted by the transponder, received back by the four bases, producing four ranging measurements which are processed to determine uniquely the time delays undergone in every retransmission process. A minimization function is derived comparing repeater’s positions referred to at least two groups of three reference bases, providing the signal transit time at the repeater and propagation delays, providing the correct repeater position. The method is applicable to the transponder platform positioning and navigation, time synchronization of remote clocks, and location of targets. The algorithm has been demonstrated by simulations adopting a practical example with the transponder carried by an aircraft moving over bases on the ground.

  8. Wax-matrix tablet for time-dependent colon-specific delivery system of sophora flavescens Aiton: preparation and in vivo evaluation.

    Science.gov (United States)

    Zou, Meijuan; Wang, Yue; Xu, Caihong; Cheng, Gang; Ren, Jungang; Wu, Gaolei

    2009-02-01

    A wax-matrix time-dependent colon-specific tablet (WM-TDCS) was studied. Wax-matrix tablet core consisting of semi-synthetic glycerides, as a wax polymeric expanding agent, carboxymethyl starch sodium (CMS-Na), and NaCl was prepared, and Sophora flavescens Aiton (ASF, extracts of traditional Chinese medicine) was used as model drug. The wax-matrix ASF tablets core was coated with Eudragit NE 30 D as the inner coating materials and with Opadry OY-P-7171 as the outer coating materials. The in vitro release behaviors of the coated tablets were examined and then in vivo absorption kinetics of the coated tablets in dogs was further investigated. The volume of the tablet core was markedly increased at 37 degrees C because of the expand effect of polymer semi-synthetic glycerides and CMS-Na. The drug release from WM-TDCS was more stable than TDCS in vitro and in vivo. The lag time of ASF release was also controlled by the thickness of the inner coating layer. In vivo evaluation demonstrated that in vivo lag time of absorption was in a good agreement with in vitro lag time of release. ASF wax-matrix tablets coated with Eudragit NE 30 D and Opadry OY-P-7171 using the regular coating technique could be designed to achieve a lag time of 3 h in the small intestinal tract.

  9. Pan-colonic pharmacokinetics of catechins and procyanidins in male Sprague-Dawley rats.

    Science.gov (United States)

    Goodrich, Katheryn M; Smithson, Andrew T; Ickes, Anne K; Neilson, Andrew P

    2015-10-01

    Poor absorption and bioavailability of procyanidins from the upper gastrointestinal tract result in the majority of the dose reaching the colon. During colonic transit, progressive microbial metabolism likely produces gradients of procyanidins and microbial metabolites along the length of the colon, suggesting that proximal and distal regions are exposed to different profiles of procyanidins and metabolites. However, previous studies have largely treated the colon as a single organ or looked at fecal profiles, and differences in the profiles of native and metabolite compounds between regions have not been observed. The metabolism kinetics of procyanidins larger than trimers and formation of metabolites in the colon have not been well characterized. Therefore, the objective of this study was to determine the kinetics of delivery and microbial metabolism of monomeric, dimeric and oligomeric procyanidins in the cecum and proximal, mid and distal colon. Sprague-Dawley rats were gavaged grape seed extract and sacrificed over 18 h. Analysis of luminal contents showed distinct native and metabolite profiles for each region. Procyanidins had maximum concentrations at approximately 3h postgavage for all sections. Metabolites reached maximum concentrations from 3 to 18 h postgavage. The appearance of metabolites was highly dependent on species: larger metabolites were found at earlier times in the more proximal segments, and smaller metabolites were found at later times in more distal regions. This study allowed for the observation of regions in the lower gastrointestinal tract, giving insight into the distribution and delivery of procyanidins and their microbial metabolites throughout the colon.

  10. Canada's international response to HIV during times of global transition: a qualitative inquiry.

    Science.gov (United States)

    Nixon, Stephanie

    2011-04-01

    Canada's international response to HIV may be under threat given CIDA's new aid priorities that appear to exclude health. Drivers of this recent priority shift have been the influence of global aid trends among public sector donors and changes within the global HIV milieu itself. However, this is not the first time Canada has shifted in response to these two global trends. The era from 2000-2004 also witnessed dramatic changes in both the HIV field and in global thinking around international aid. As such, this article presents an evaluation of the Government of Canada's international response to HIV during the first era of transition (2000-2004) in order to derive lessons for decision-making around HIV in the current climate of change. In-depth, semi-structured interviews were conducted with 23 key informants with expertise regarding Canada's international response to HIV over time. Analysis involved multiple readings of transcripts to identify descriptive codes and establish intimacy with the data. Descriptive codes were then collapsed into thematic categories using a process of inductive reasoning. Canada's international response to HIV was perceived to be exemplary at times (e.g. seminal funding to WHO's "3-by-5" strategy), but also inconsistent (e.g., underutilized technical assistance capacity) and non-strategic (e.g., contradiction between investing in training health providers while poaching professionals to bolster Canada's workforce). Lessons from the 2000-2004 era of transition focus on strategic investments, the inextricable connection between HIV and development and strategy coherence. These results highlight that it is more constructive to ensure that Canadian development responses in all areas engage with both the upstream drivers of HIV as well as the impacts of the epidemic itself in order to achieve the greatest results from international investment and the most effective contributions to the lives of the people that these endeavours seek to

  11. Altered Colonic Bacterial Fermentation as a Potential Pathophysiological Factor in Irritable Bowel Syndrome.

    Science.gov (United States)

    Ringel-Kulka, Tamar; Choi, Chang Hwan; Temas, Daniel; Kim, Ari; Maier, Daniele M; Scott, Karen; Galanko, Joseph A; Ringel, Yehuda

    2015-09-01

    Dysbiosis leading to abnormal intestinal fermentation has been suggested as a possible etiological mechanism in irritable bowel syndrome (IBS). We aimed to investigate the location and magnitude of altered intestinal bacterial fermentation in IBS and its clinical subtypes. IBS patients who satisfied the Rome III criteria (114) and 33 healthy controls (HC) were investigated. Intestinal fermentation was assessed using two surrogate measures: intestinal intraluminal pH and fecal short-chain fatty acids (SCFAs). Intraluminal pH and intestinal transit times were measured in the small and large bowel using a wireless motility capsule (SmartPill) in 47 IBS and 10 HC. Fecal SCFAs including acetate, propionate, butyrate, and lactate were analyzed by capillary gas chromatography in all enrolled subjects. Correlations between intestinal pH, fecal SCFAs, intestinal transit time, and IBS symptom scores were analyzed. Colonic intraluminal pH levels were significantly lower in IBS patients compared with HC (total colonic pH, 6.8 for IBS vs. 7.3 for HC, P=0.042). There were no differences in total and segmental pH levels in the small bowel between IBS patients and HC (6.8 vs. 6.8, P=not significant). The intraluminal colonic pH differences were consistent in all IBS subtypes. Total SCFA level was significantly lower in C-IBS patients than in D-IBS and M-IBS patients and HC. The total SCFA level in all IBS subjects was similar with that of HC. Colonic pH levels correlated positively with colon transit time (CTT) and IBS symptoms severity. Total fecal SCFAs levels correlated negatively with CTT and positively with stool frequency. Colonic intraluminal pH is decreased, suggesting higher colonic fermentation, in IBS patients compared with HC. Fecal SCFAs are not a sensitive marker to estimate intraluminal bacterial fermentation.

  12. Impacts of peripheral obestatin on colonic motility and secretion in conscious fed rats.

    Science.gov (United States)

    Chen, C Y; Chien, E J; Chang, F Y; Lu, C L; Luo, J C; Lee, S D

    2008-09-01

    Obestatin, a novel putative 23-amino acid peptide, was found to be derived from a mammalian preproghrelin gene by using a bioinformatics approach. Although the effects of obestatin on food intake and upper gut motility remain controversial, no studies have been carried out to explore its influence on lower gut motility and secretion. We investigated the impacts of intravenous (IV) injection of obestatin on rat colonic motor and secretory functions. Colonic transit time, fecal pellet output, and fecal content were measured in freely fed, conscious rats, which were chronically implanted with IV and colonic catheters. To test the validity of this animal model, human/rat corticotropin-releasing factor (h/rCRF) served as a stimulatory inducer of colonic motility and secretion. IV injection of obestatin (45, 100, and 300 nmol/kg) did not affect the colonic transit time, whereas IV injection of h/rCRF (30 nmol/kg) effectively accelerated colonic transit time. IV obestatin, in every dose we tested, also did not modify fecal pellet output, frequency of watery diarrhea, total fecal weight, fecal dried solid weight, or fecal fluid weight in the first hour after injection. On the other hand, IV injection of h/rCRF significantly enhanced fecal pellet output, as well as increased the frequency of watery diarrhea, total fecal weight, fecal dried solid weight, and fecal fluid weight during the first hour after injection compared with IV saline controls. In conclusion, peripheral obestatin administration has no impact on colonic motility and secretion in conscious fed rats.

  13. VIDEO CAPSULE ENDOSCOPY: A TOOL FOR THE ASSESSMENT OF SMALL BOWEL TRANSIT TIME

    Directory of Open Access Journals (Sweden)

    Reza A Hejazi

    2016-02-01

    Full Text Available Purpose: Video capsule endoscopy (VCE is a procedure that uses a wireless camera to take pictures of the gastrointestinal tract. A wireless motility capsule (WMC of a similar size has been developed, which measures pH, pressure, and temperature, and can be used to assess regional and total gastrointestinal transit times. VCE could also potentially be used as a tool for measuring small bowel transit time (SBTT.Methods: This study was designed to obtain SBTT from VCE and compare it with historical data generated by WMC. Gastric transit time (GTT was also measured. Patients were included if the indication for VCE was either iron deficiency anemia (IDA or overt obscure GI bleed (OOGIB and they did not have any known motility disorder. Results from VCE were also compared in diabetic versus non-diabetic patients. Results: There were a total of 147 VCE studies performed, including 42 for OOGIB and 105 for IDA. Median GTT and SBTT were 0.3 and 3.6 hours, respectively. The overall median GTT and SBTT were 0.3 and 3.6 hours, respectively, in the IDA group compared with 0.3 and 3.4 hours in the OOGIB group. When compared with WMC, the GTT and SBTT were significantly faster in both groups (GTT: 3.6 hours and SBTT: 4.6 hours. The median GTT and SBTT were not significantly different in diabetics versus non-diabetics: (GTT: 17.5 vs. 18.0 minutes (P=0.86 and SBTT: 3.9 hours (237 minutes vs. 3.8 hours (230 minutes, respectively (P=0.90.Conclusion: SBTT as measured using VCE is not significantly different in OOGIB compared with IDA. Both GTT and SBTT are significantly faster as assessed by VCE, which is initiated in the fasting state, compared with WMC measurement, which is initiated after a standard meal. In summary, VCE could potentially be used for measuring SBTT in the fasting state.

  14. Transition state trajectory stability determines barrier crossing rates in chemical reactions induced by time-dependent oscillating fields

    CERN Document Server

    Craven, Galen T; Hernandez, Rigoberto

    2015-01-01

    When a chemical reaction is driven by an external field, the transition state that the system must pass through as it changes from reactant to product -for example, an energy barrier- becomes time-dependent. We show that for periodic forcing the rate of barrier crossing can be determined through stability analysis of the non-autonomous transition state. Specifically, strong agreement is observed between the difference in the Floquet exponents describing stability of the transition state trajectory, which defines a recrossing-free dividing surface [G. T. Craven, T. Bartsch, and R. Hernandez, Phys. Rev. E 89, 040801(R) (2014)], and the rates calculated by simulation of ensembles of trajectories. This result opens the possibility to extract rates directly from the intrinsic stability of the transition state, even when it is time-dependent, without requiring a numerically-expensive simulation of the long-time dynamics of a large ensemble of trajectories.

  15. A Continuous Time Random Walk Description of Monodisperse, Hard-Sphere Colloids below the Ordering Transition

    Science.gov (United States)

    Lechman, Jeremy; Pierce, Flint

    2012-02-01

    Diffusive transport is a ubiquitous process that is typically understood in terms of a classical random walk of non-interacting particles. Here we present the results for a model of hard-sphere colloids in a Newtonian incompressible solvent at various volume fractions below the ordering transition (˜50%). We numerically simulate the colloidal systems via Fast Lubrication Dynamics -- a Brownian Dynamics approach with corrected mean-field hydrodynamic interactions. Colloid-colloid interactions are also included so that we effectively solve a system of interacting Langevin equations. The results of the simulations are analyzed in terms of the diffusion coefficient as a function of time with the early and late time diffusion coefficients comparing well with experimental results. An interpretation of the full time dependent behavior of the diffusion coefficient and mean-squared displacement is given in terms of a continuous time random walk. Therefore, the deterministic, continuum diffusion equation which arises from the discrete, interacting random walkers is presented. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  16. Reformulation of time-convolutionless mode-coupling theory near the glass transition

    Science.gov (United States)

    Tokuyama, Michio

    2017-10-01

    The time-convolutionless mode-coupling theory (TMCT) recently proposed is reformulated under the condition that one of two approximations, which have been used to formulate the original TMCT in addition to the MCT approximations done on a derivation of nonlinear memory function in terms of the intermediate-scattering function, is not employed because it causes unphysical results for intermediate times. The improved TMCT equation is then derived consistently under another approximation. It is first checked that the ergodic to non-ergodic transition obtained by a new equation is exactly the same as that obtained by an old one because the long-time dynamics of both equations coincides with each other. However, it is emphasized that a difference between them appears in the intermediate-time dynamics of physical quantities. Such a difference is explored numerically in the dynamics of a non-Gaussian parameter by employing the Percus-Yevick static structure factor to calculate the nonlinear memory function.

  17. Phase Transition for the Mixing Time of the Glauber Dynamics for Coloring Regular Trees

    CERN Document Server

    Tetali, Prasad; Vigoda, Eric; Yang, Linji

    2009-01-01

    We prove that the mixing time of the Glauber dynamics for random $k$-colorings of the complete tree with branching factor $b$ undergoes a phase transition at $k=b(1+o_b(1))/\\ln{b}$. Our main result shows nearly sharp bounds on the mixing time of the dynamics on the complete tree with $n$ vertices for $k=Cb/\\ln{b}$ colors with constant $C$. For $C\\geq 1$ we prove the mixing time is $O(n^{1+o_b(1)}\\ln^2{n})$. On the other side, for $C< 1$ the mixing time experiences a slowing down, in particular, we prove it is $O(n^{1/C + o_b(1)}\\ln^2{n})$ and $\\Omega(n^{1/C-o_b(1)})$. The critical point C=1 is interesting since it coincides (at least up to first order) to the so-called reconstruction threshold which was recently established by Sly. The reconstruction threshold has been of considerable interest recently since it appears to have close connections to the efficiency of certain local algorithms, and this work was inspired by our attempt to understand these connections in this particular setting.

  18. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    Science.gov (United States)

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  19. 77 FR 77180 - Notice of Transportation Services' OMB Designation, timely return of excess transit benefits to...

    Science.gov (United States)

    2012-12-31

    ... purposes of this notice with respect to the minimum internal controls, the following definitions are... transit benefit amount. 2. With respect to van pools, the agency transit benefit program manager should... workplace parking permit, are not eligible to receive the transit benefit. However, the allowable cost for...

  20. A transit timing analysis of nine RISE light curves of the exoplanet system TrES-3

    CERN Document Server

    Gibson, N P; Skillen, I; Simpson, E K; Barros, S; Joshi, Y C; Todd, I; Benn, C; Christian, D; Hrudková, M; Keenan, F P; Steele, I A

    2009-01-01

    We present nine newly observed transits of TrES-3, taken as part of a transit timing program using the RISE instrument on the Liverpool Telescope. A Markov-Chain Monte-Carlo analysis was used to determine the planet-star radius ratio and inclination of the system, which were found to be Rp/Rstar=0.1664^{+0.0011}_{-0.0018} and i = 81.73^{+0.13}_{-0.04} respectively, consistent with previous results. The central transit times and uncertainties were also calculated, using a residual-permutation algorithm as an independent check on the errors. A re-analysis of eight previously published TrES-3 light curves was conducted to determine the transit times and uncertainties using consistent techniques. Whilst the transit times were not found to be in agreement with a linear ephemeris, giving chi^2 = 35.07 for 15 degrees of freedom, we interpret this to be the result of systematics in the light curves rather than a real transit timing variation. This is because the light curves that show the largest deviation from a con...

  1. Abnormal colonic motility in mice overexpressing human wild-type alpha-synuclein.

    Science.gov (United States)

    Wang, Lixin; Fleming, Sheila M; Chesselet, Marie-Françoise; Taché, Yvette

    2008-05-28

    The presynaptic protein alpha-synuclein (alphaSyn) has been implicated in both familial and sporadic forms of Parkinson's disease. We examined whether human alphaSyn-overexpressing mice under Thy1 promoter (Thy1-alphaSyn) display alterations of colonic function. Basal fecal output was decreased in Thy1-alphaSyn mice fed ad libitum. Fasted/refed Thy1-alphaSyn mice had a slower distal colonic transit than the wild-type mice, as monitored by 2.2-fold increase in time to expel an intracolonic bead and 2.9-fold higher colonic fecal content. By contrast, Thy1-alphaSyn mice had an increased fecal response to novelty stress and corticotropin releasing factor injected intraperipherally. These results indicate that Thy1-alphaSyn mice display altered basal and stress-stimulated propulsive colonic motility and will be a useful model to study gut dysfunction associated with Parkinson's disease.

  2. Time-dependent sleep stage transition model based on heart rate variability.

    Science.gov (United States)

    Takeda, Toki; Mizuno, Osamu; Tanaka, Tomohiro

    2015-01-01

    A new model is proposed to automatically classify sleep stages using heart rate variability (HRV). The generative model, based on the characteristics that the distribution and the transition probabilities of sleep stages depend on the elapsed time from the beginning of sleep, infers the sleep stage with a Gibbs sampler. Experiments were conducted using a public data set consisting of 45 healthy subjects and the model's classification accuracy was evaluated for three sleep stages: wake state, rapid eye movement (REM) sleep, and non-REM sleep. Experimental results demonstrated that the model provides more accurate sleep stage classification than conventional (naive Bayes and Support Vector Machine) models that do not take the above characteristics into account. Our study contributes to improve the quality of sleep monitoring in the daily life using easy-to-wear HRV sensors.

  3. The $\\eta^\\prime$ transition form factor from space- and time-like experimental data

    CERN Document Server

    Escribano, Rafel; Masjuan, Pere; Sanchez-Puertas, Pablo

    2015-01-01

    The $\\eta^\\prime$ transition form factor is reanalysed in view of the recent BESIII first observation of the Dalitz decay $\\eta^\\prime\\to\\gamma e^+e^-$ in both space- and time-like regions at low and intermediate energies using the Pad\\'e approximants method. The present analysis provides a suitable parameterization for reproducing the measured form factor in the whole energy region and allows to extract the corresponding low-energy parameters together with a prediction of its values at the origin, related to $\\Gamma_{\\eta^\\prime\\to\\gamma\\gamma}$, and the asymptotic limit. The $\\eta$-$\\eta^\\prime$ mixing is reassessed, with particular attention to the OZI-rule violating parameters, and the $J/\\psi\\to\\eta^{(\\prime)}\\gamma$ decays discussed.

  4. Transition among synchronous schemes in coupled nonidentical multiple time delay systems

    Energy Technology Data Exchange (ETDEWEB)

    Thang Manh Hoang [Department of Electronics and Informatics, Faculty of Electronics and Telecommunications, Hanoi University of Technology, 1 Dai Co Viet, Hanoi (Viet Nam)], E-mail: hmt@mail.hut.edu.vn

    2009-10-30

    We present the transition among possible synchronous schemes in coupled nonidentical multiple time delay systems, i.e., lag, projective-lag, complete, anticipating and projective-anticipating synchronization. The number of nonlinear transforms in the master's equation can be different from that in slave's, and nonlinear transforms can be in various forms. The driving signal is the sum of nonlinearly transformed components of delayed state variable. Moreover, the equation representing for driving signal is constructed exactly so that the difference between the master's and slave's structures is complemented. The sufficient condition for synchronization is considered by the Krasovskii-Lyapunov theory. The specific examples will demonstrate and verify the effectiveness of the proposed models.

  5. Education and fertility decline in China during transitional times: A cohort approach.

    Science.gov (United States)

    Piotrowski, Martin; Tong, Yuying

    2016-01-01

    We examine the effect of education on birth outcomes in China during the period of economic transition and large-scale changes in mass education and population control measures. Retrospective micro data from the 2008 Chinese General Social Survey and discrete time event history analysis are used to examine the fertility history of several cohorts of women born between 1945 and 1968. We observed births at different parities, distinguishing the education effect across cohorts and rural/urban sectors. We found differences across cohorts consistent with unique features of the Chinese context, such as the radical egalitarian era of educational expansion, and the Reform Era. We also found that despite the increase in some education levels across cohorts (e.g., junior high school in rural areas), birth chances were more likely to be concentrated among less educated women, suggesting the impact of factors related to returns to education and hence the desire for children. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Anomalous parity-time-symmetry transition away from an exceptional point

    Science.gov (United States)

    Ge, Li

    2016-07-01

    Parity-time (PT ) symmetric systems have two distinguished phases, e.g., one with real-energy eigenvalues and the other with complex-conjugate eigenvalues. To enter one phase from the other, it is believed that the system must pass through an exceptional point, which is a non-Hermitian degenerate point with coalesced eigenvalues and eigenvectors. Here we reveal an anomalous PT transition that takes place away from an exceptional point in a nonlinear system: as the nonlinearity increases, the original linear system evolves along two distinct PT -symmetric trajectories, each of which can have an exceptional point. However, the two trajectories collide and vanish away from these exceptional points, after which the system is left with a PT -broken phase. We first illustrate this phenomenon using a coupled-mode theory and then exemplify it using paraxial wave propagation in a transverse periodic potential.

  7. Toward Ubiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory and Practice.

    Science.gov (United States)

    Mukkamala, Ramakrishna; Hahn, Jin-Oh; Inan, Omer T; Mestha, Lalit K; Kim, Chang-Sei; Töreyin, Hakan; Kyal, Survi

    2015-08-01

    Ubiquitous blood pressure (BP) monitoring is needed to improve hypertension detection and control and is becoming feasible due to recent technological advances such as in wearable sensing. Pulse transit time (PTT) represents a well-known potential approach for ubiquitous BP monitoring. The goal of this review is to facilitate the achievement of reliable ubiquitous BP monitoring via PTT. We explain the conventional BP measurement methods and their limitations; present models to summarize the theory of the PTT-BP relationship; outline the approach while pinpointing the key challenges; overview the previous work toward putting the theory to practice; make suggestions for best practice and future research; and discuss realistic expectations for the approach.

  8. Anomalous Parity-Time Symmetry Transition away from an Exceptional Point

    CERN Document Server

    Ge, Li

    2016-01-01

    Parity-time (PT) symmetric systems have two distinguished phases, e.g., one with real energy eigenvalues and the other with complex conjugate eigenvalues. To enter one phase from the other, it is believed that the system must pass through an exceptional point, which is a non-Hermitian degenerate point with coalesced eigenvalues and eigenvectors. In this letter we reveal an anomalous PT transition that takes place away from an exceptional point in a nonlinear system: as the nonlinearity increases, the original linear system evolves along two distinct PT-symmetric trajectories, each of which can have an exceptional point. However, the two trajectories collide and vanish away from these exceptional points, after which the system is left with a PT-broken phase. We first illustrate this phenomenon using a coupled mode theory and then exemplify it using paraxial wave propagation in a transverse periodic potential.

  9. Sensitivity bias in the mass-radius distribution from Transit Timing Variations and Radial Velocity measurements

    CERN Document Server

    Steffen, Jason H

    2015-01-01

    Motivated by recent discussions, both in private and in the literature, we use a Monte Carlo simulation of planetary systems to investigate sources of bias in determining the mass-radius distribution of exoplanets for the two primary techniques used to measure planetary masses---Radial Velocities (RVs) and Transit Timing Variations (TTVs). We assert that mass measurements derived from these two methods are comparably reliable---as the physics underlying their respective signals is well understood. Nevertheless, their sensitivity to planet mass varies with the properties of the planets themselves. We find that for a given planet size, the RV method tends to find planets with higher mass while the sensitivity of TTVs is more uniform. This ``sensitivity bias'' implies that a complete census of TTV systems is likely to yield a more robust estimate of the mass-radius distribution provided there are not important physical differences between planets near and far from mean-motion resonance. We discuss differences in...

  10. The experimental investigation of the X-band transit-time tube oscillator

    CERN Document Server

    MaQiaoSheng; Fan Zhi Kai; Hu Hai Ying; LiuQingXiang; Su Chang

    2002-01-01

    The experimental investigation of X-band transit-time tube oscillator on the accelerator Sinus-700 is described. The accelerator is adjusted so that it can work stably; some parameters which influence the operation of the microwave device are adjusted so that the appropriate values of the parameters are obtained. The appropriate values of the parameters are described as follow: the length of the 1/4 wavelength stand equals 8 mm, the strength of the magnetic field 1.75 T, the voltage of the diode 700 kV and the shape of the cathode is annular. As a result, the microwave frequency is 9.18 GHz, the microwave power 1.5 GW, the pulse width 26 ns and the power conversion efficiency 31%

  11. Time-resolved electron-beam characterizations with optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H. (Argonne National Lab., IL (United States)); Wilke, M.D. (Los Alamos National Lab., NM (United States))

    1992-01-01

    Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 {mu}s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatial position and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kicks are reported as a function of charge.

  12. Time-resolved electron-beam characterizations with optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H. [Argonne National Lab., IL (United States); Wilke, M.D. [Los Alamos National Lab., NM (United States)

    1992-09-01

    Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 {mu}s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatial position and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kicks are reported as a function of charge.

  13. Further time-resolved electron-beam characterizations with optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H. (Argonne National Lab., IL (United States). Advanced Photon Source Accelerator Systems Div.); Wilke, M.D. (Los Alamos National Lab., NM (United States))

    1992-01-01

    Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 [mu]s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatialposition and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kick effects are reported as a function of charge.

  14. Further time-resolved electron-beam characterizations with optical transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A.H. [Argonne National Lab., IL (United States). Advanced Photon Source Accelerator Systems Div.; Wilke, M.D. [Los Alamos National Lab., NM (United States)

    1992-12-31

    Time-resolved characterizations of electron beams using optical transition radiation (OTR) as a prompt conversion mechanism have recently been extended on the Los Alamos Free-electron Laser (FEL) facility 40-MeV linac. Two key timescales for rf-linac driven FELs are the micropulse (10 ps) and the macropulse (5 {mu}s to 1 ms). In the past we have used gated, intensified cameras to select a single or few micropulses (25 to 400 ns gate width) out of the pulse train to evaluate submacropulse effects. Recently, we have obtained some of the first measurements of micropulse bunch length (7 to 10 ps) and submacropulse spatialposition and profile using OTR and a Hamamatsu streak camera. Additionally, micropulse elongation effects and head-to-tail transverse kick effects are reported as a function of charge.

  15. The City: Spaces, Times and Subjects in the Global Transition (edited by Niccolò Cuppini

    Directory of Open Access Journals (Sweden)

    Niccolò Cuppini

    2015-12-01

    Full Text Available Within the entering in the global era, the city is come back again as a strategic architrave of the world's infrastructure – while the State, the historical figure through which Modernity was organized, has been declared in crisis long time ago. Despite the broad spectrum of urban reflections, there still is a deep lack of political theory of the city. The globalization of the city – within the pathway of the planetary urbanization – is the object of the article, that elaborates on a twofold level: on one hand, a genealogical trace of that process is proposed – articulating it by distilling urban political thought from different authors and historical episodes; on the other hand, the article suggests a theoretical and methodological horizon through which to grasp the contemporary global transitions, labelled as “seeing like a city”.

  16. Spike-timing-dependent plasticity enhanced synchronization transitions induced by autapses in adaptive Newman-Watts neuronal networks.

    Science.gov (United States)

    Gong, Yubing; Wang, Baoying; Xie, Huijuan

    2016-12-01

    In this paper, we numerically study the effect of spike-timing-dependent plasticity (STDP) on synchronization transitions induced by autaptic activity in adaptive Newman-Watts Hodgkin-Huxley neuron networks. It is found that synchronization transitions induced by autaptic delay vary with the adjusting rate Ap of STDP and become strongest at a certain Ap value, and the Ap value increases when network randomness or network size increases. It is also found that the synchronization transitions induced by autaptic delay become strongest at a certain network randomness and network size, and the values increase and related synchronization transitions are enhanced when Ap increases. These results show that there is optimal STDP that can enhance the synchronization transitions induced by autaptic delay in the adaptive neuronal networks. These findings provide a new insight into the roles of STDP and autapses for the information transmission in neural systems. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  17. Pathways and transit time of meltwater in the englacial drainage system of Rabots Glacier, Kebnekaise, Sweden

    Science.gov (United States)

    Coch, Caroline; Clason, Caroline; Rosqvist, Gunhild; Jarsjö, Jerker; Brugger, Keith

    2014-05-01

    Following the crash of a Norwegian Hercules plane in the Kebnekaise mountain range in March 2012, a field campaign was initiated in order to assess the fate of the hydrocarbon pollution in the glacial system. Monitoring of pollution was conducted in the snow pack of Rabots glacier, as well as in the proglacial stream, and the preferential pathways for transport of pollutants were assessed. Since it is likely that soluble components of the aircraft fuel are transported within the glacial meltwater, our study focuses on constraining the likely transit time and dispersion of these components. The hydrologic configuration of Rabots glacier was thus studied during the 2013 ablation season by means of dye tracing experiments and discharge monitoring in the proglacial stream. The analyses of the dye return curves and stream monitoring suggest different hydrological configurations on the north and south side of the glacier, perhaps influenced by shading and the ice thermal structure. The system on the north side seems to be distributed, with extensive interaction of meltwater with the bed, as typified in the turbid proglacial outlet. The distinct peaks of the return curves on the south side indicate efficient transport, perhaps largely through englacial channels, given the relatively clear nature of the proglacial outlet. The evaluation of transit speed along a longitudinal profile contributed to the understanding of drainage efficiency with distance upglacier. The higher up the injection location on the glacier, the more distributed and less efficient the system. The seasonal evolution of efficiency was also assessed, showing an increase inefficiency with time. Furthermore, we hypothesize a disconnect in the glacial hydrological systems on the north and south side of the glacier. Pollution that is transported with the meltwater down from the crash site on the southern side most likely does not reach the drainage system on the northern side. Besides revealing potential

  18. Empirical Assessment on Factors Affecting Travel Time of Bus Rapid Transit

    Directory of Open Access Journals (Sweden)

    Fergyanto E Gunawan

    2015-02-01

    Full Text Available Since the beginning of the century, many cities around the world adopt the bus rapid transit (BRT system to fulfill their need of mass transportation system. The system features with platform-level boarding, bus lanes in the central verge of the road, off-vehicle fare collection, and physically protected busway. So far, these criteria are considered to be the most important aspects with respect to the BRT performance. In this research, we intend to study to what extent the BRT performance may be affected by the interference of the mixed traffic during the BRT operation. We adopt an empirical approach by observing the phenomenon unfolding in the eleven TransJakarta BRT corridors. The TransJakarta BRT operates in the city of Jakarta, the capital of the Republic of Indonesia. We record the travel time data from station to station for the case where the TransJakarta bus can travel smoothly and the case where the traveling bus is interfered with the mixed traffic. For the cases, we evaluate the travel time variation. As the results, we found that the Corridor 1 of TransJakarta BRT has the best performance in term of the travel time variation. For the two directions, the corridor has the mean travel time of 34 min, the standard deviation of 3 min, and the travel time variation of 8%. On this corridor, the mixed-traffic interference is relatively negligible. On the Corridor 7, the two-direction travel times have the mean of 45 min, the standard deviation of 8 min, and the travel time variation of 16%. On the Corridor 9, the twodirection travel times have the mean of 1 hr and 25 min, the standard deviation of 11 min, and the travel time variation of 14%. On the last two corridors, the busways are heavily interfered by the mixed traffic; thus, the end-to-end travel times are significantly uncertain although only very few road segments are interfered. The research leads us to a conclusion that the interference, although only occurs on a road segment, may

  19. Convergence Time and Phase Transition in a Non-monotonic Family of Probabilistic Cellular Automata

    Science.gov (United States)

    Ramos, A. D.; Leite, A.

    2017-08-01

    In dynamical systems, some of the most important questions are related to phase transitions and convergence time. We consider a one-dimensional probabilistic cellular automaton where their components assume two possible states, zero and one, and interact with their two nearest neighbors at each time step. Under the local interaction, if the component is in the same state as its two neighbors, it does not change its state. In the other cases, a component in state zero turns into a one with probability α , and a component in state one turns into a zero with probability 1-β . For certain values of α and β , we show that the process will always converge weakly to δ 0, the measure concentrated on the configuration where all the components are zeros. Moreover, the mean time of this convergence is finite, and we describe an upper bound in this case, which is a linear function of the initial distribution. We also demonstrate an application of our results to the percolation PCA. Finally, we use mean-field approximation and Monte Carlo simulations to show coexistence of three distinct behaviours for some values of parameters α and β.

  20. Time-resolved four-wave-mixing spectroscopy for inner-valence transitions.

    Science.gov (United States)

    Ding, Thomas; Ott, Christian; Kaldun, Andreas; Blättermann, Alexander; Meyer, Kristina; Stooss, Veit; Rebholz, Marc; Birk, Paul; Hartmann, Maximilian; Brown, Andrew; Van Der Hart, Hugo; Pfeifer, Thomas

    2016-02-15

    Noncollinear four-wave-mixing (FWM) techniques at near-infrared (NIR), visible, and ultraviolet frequencies have been widely used to map vibrational and electronic couplings, typically in complex molecules. However, correlations between spatially localized inner-valence transitions among different sites of a molecule in the extreme ultraviolet (XUV) spectral range have not been observed yet. As an experimental step toward this goal, we perform time-resolved FWM spectroscopy with femtosecond NIR and attosecond XUV pulses. The first two pulses (XUV-NIR) coincide in time and act as coherent excitation fields, while the third pulse (NIR) acts as a probe. As a first application, we show how coupling dynamics between odd- and even-parity, inner-valence excited states of neon can be revealed using a two-dimensional spectral representation. Experimentally obtained results are found to be in good agreement with ab initio time-dependent R-matrix calculations providing the full description of multielectron interactions, as well as few-level model simulations. Future applications of this method also include site-specific probing of electronic processes in molecules.

  1. Spin time-relaxation within strongly coupled paramagnetic systems exhibiting paramagnetic-ferrimagnetic transitions

    CERN Document Server

    Chahid, M

    2000-01-01

    The purpose of the present work is a quantitative study of the spin time relaxation within superweak ferrimagnetic materials exhibiting a paramagnetic-ferrimagnetic transition, when the temperature is changed from an initial value T sub i to a final one T sub f very close to the critical temperature T sub c. From a magnetic point of view, the material under investigation is considered to be made of two strongly coupled paramagnetic sublattices of respective moments phi (cursive,open) Greek and psi. Calculations are made within a Landau mean-field theory, whose free energy involves, in addition to quadratic and quartic terms in both moments phi (cursive,open) Greek and psi, a lowest-order coupling - Cphi (cursive,open) Greek psi, where C<0 stands for the coupling constant measuring the interaction between the two sublattices. We first determine the time dependence of the shifts of the order parameters delta phi (cursive,open) Greek and delta psi from the equilibrium state. We find that this time dependence ...

  2. Time-resolved four-wave-mixing spectroscopy for inner-valence transitions

    CERN Document Server

    Ding, Thomas; Kaldun, Andreas; Blättermann, Alexander; Meyer, Kristina; Stooß, Veit; Rebholz, Marc; Birk, Paul; Hartmann, Maximilian; Brown, Andrew; Van Der Hart, Hugo; Pfeifer, Thomas

    2015-01-01

    Non-collinear four-wave mixing (FWM) techniques at near-infrared (NIR), visible, and ultraviolet frequencies have been widely used to map vibrational and electronic couplings, typically in complex molecules. However, correlations between spatially localized inner-valence transitions among different sites of a molecule in the extreme ultraviolet (XUV) spectral range have not been observed yet. As an experimental step towards this goal we perform time-resolved FWM spectroscopy with femtosecond NIR and attosecond XUV pulses. The first two pulses (XUV-NIR) coincide in time and act as coherent excitation fields, while the third pulse (NIR) acts as a probe. As a first application we show how coupling dynamics between odd- and even-parity inner-valence excited states of neon can be revealed using a two-dimensional spectral representation. Experimentally obtained results are found to be in good agreement with ab initio time-dependent R-matrix calculations providing the full description of multi-electron interactions,...

  3. Inflationary spectra from near $\\Omega$-deformed space-time transition point in Loop Quantum Cosmology

    CERN Document Server

    Chen, Long

    2016-01-01

    Anomaly-free perturbations of loop quantum cosmology with holonomy corrections reveal a $\\Omega$ -deformed space-time structure, $\\Omega:=1-2\\rho/\\rho_c$, where $\\Omega0$ means a Lorentz-like space. It would be reasonable to give the initial value at the space-time transition point, $\\rho=\\rho_c/2$, but we find it is impossible to define a Minkowski-like vacuum even for large $k$-modes at that time. However if we loose the condition and give the initial value near after $\\Omega=0$, e.g. $\\Omega\\simeq 0.2$, the vacuum state can be well defined and furthermore the slow roll approximation also works well in that region. Both scalar and tensor spectra are considered in the framework of loop quantum cosmology with holonomy corrections. We find that if the energy density is not too small compared with $\\rho_c/2$ when the considered $k$-mode crossing the horizon, effective theory can give a much smaller scalar power spectrum than classical theory and the spectrum of tensor perturbations could blue shift. But when co...

  4. Motion artefact reduction of the photoplethysmographic signal in pulse transit time measurement.

    Science.gov (United States)

    Foo, J Y A; Wilson, S J; Williams, G R; Harris, M; Cooper, D M

    2004-12-01

    Motion artefact is a common occurrence that contaminates photoplethysmographic (PPG) measurements. To extract timing information from signals during artefact is challenging. PPG signal is very sensitive to artefacts and can be used in applications like, pulse transit time (PTT) as part of the polysomnographic studies. A correlation cancellation or signal processing approach is implemented with the adaptive cancelling filter concept and a triaxial accelerometry. PPG signals obtained from a Masimo (Reference) pulse oximeter is used as reference to compare with the reconstructed PPG signals. Different hands are used for each PPG source, one stationary while the other involves typical movements during sleep. A second Masimo pulse oximeter is used to register intensity of timing errors on commercial PPG signals. 108 PTT measurements are recorded in three different movements with PTT estimates from unprocessed PPG signals showing 35.51+/-27.42%, Masimo 50.02+/-29.40% and reconstructed 4.32+/-3.59% difference against those from the Reference PPG. The triaxial accelerometry can be used to detect the presence of artefact on PPG signals. This is useful in PTT measurements when signal contaminated with artefacts are required for further analysis, especially after and during arousals in sleep. The suggested filtering model can then reconstruct these corrupted PPG signals.

  5. Laparoscopic colonic exclusion for treating slow transit constipation patients%腹腔镜下结肠旷置术治疗结肠慢传输性便秘的临床研究

    Institute of Scientific and Technical Information of China (English)

    付焱; 李恒; 代全武; 刘全; 黄东; 孙敏; 但超; 汪胜胜

    2013-01-01

    目的 总结腹腔镜下结肠旷置术治疗慢传输型便秘(STC)的体会.方法 23例STC患者,行腹腔镜下结肠旷置术.对患者的临床资料、手术相关指标及术后随访结果 进行分析.采用胃肠道生活质量评分及Wexner便秘评分进行术后长期随访评估手术疗效.结果 23例患者均成功施行手术,无肠瘘、盆腔感染、吻合口狭窄、切口感染、术后粘连性肠梗阻、肛门失禁等并发症发生.术后第一天进流质饮食,平均1.5d排气,2d排便.手术后平均住院时间7d.术后随访1~48个月,患者便秘症状指标明显改善,均达到治愈标准.胃肠生活质量术前评分为(79.2±15.8)分,术后3个月(92.3±12.7)分,术后6个月(103.5±9.2)分,术后12个月(107.9±9.8)分,术后24个月(112.3±10.3)分,随访中显示持续下降,与术前比较,差异均有统计学意义(P<0.05).Wexner便秘评分由术前的(19.2±4.1)分降至术后3个月的(8.3±2.1)分,差异亦有统计学意义(P<0.05);便秘评分的下降一直维持到术后24个月.结论 腹腔镜结肠旷置术整合双重微创优势,近期疗效和生活质量满意,是治疗STC的微创术式.%Objective To investigate the feasibility and efficacy of laparoscopic colonic exclusion ( CE )for severe slow transit constipation( STC ). Methods Twenty-three patients with STC underwent laparoscopic CE. The general clinical data,related surgical indications and follow-up time were analyzed. Gastrointestinal quality of life index( GIQLI )and Wexner scale were collected to evaluate the long-term outcomes of surgery. Results All the procedures were successfully performed. No complications such as a-nal anastomotic fistula, pelvic infection, anastomotic stenosis, adhesive intestinal obstruction and incontinence occurred. All patients took liquid diet on the first day after the operation. The mean exhaust time was 1. 5 d, the mean defecation time was 2 d and the average hospital stay was 7 d. The mean follow-up time

  6. Starting Out: A time-lagged study of new graduate nurses' transition to practice.

    Science.gov (United States)

    Laschinger, Heather K Spence; Cummings, Greta; Leiter, Michael; Wong, Carol; MacPhee, Maura; Ritchie, Judith; Wolff, Angela; Regan, Sandra; Rhéaume-Brüning, Ann; Jeffs, Lianne; Young-Ritchie, Carol; Grinspun, Doris; Gurnham, Mary Ellen; Foster, Barbara; Huckstep, Sherri; Ruffolo, Maurio; Shamian, Judith; Burkoski, Vanessa; Wood, Kevin; Read, Emily

    2016-05-01

    As the nursing profession ages, new graduate nurses are an invaluable health human resource. The purpose of this study was to investigate factors influencing new graduate nurses' successful transition to their full professional role in Canadian hospital settings and to determine predictors of job and career satisfaction and turnover intentions over a one-year time period in their early employment. A national two-wave survey of new graduate nurses across Canada. A random sample of 3906 Registered Nurses with less than 3 years of experience currently working in direct patient care was obtained from the provincial registry databases across Canada. At Time 1, 1020 of 3743 eligible nurses returned completed questionnaires (usable response rate=27.3%). One year later, Time 1 respondents were mailed a follow-up survey; 406 returned a completed questionnaire (response rate=39.8%). Surveys containing standardized questionnaires were mailed to participants' home address. Descriptive statistics, correlations, and hierarchical linear regression analyses were conducted using SPSS software. Overall, new graduate nurses were positive about their experiences and committed to nursing. However, over half of new nurses in the first year of practice reported high levels of emotional exhaustion and many witnessed or experienced incivility (24-42%) at work. Findings from hierarchical linear regression analyses revealed that situational and personal factors explained significant amounts of variance in new graduate nurses' job and career satisfaction and turnover intentions. Cynicism was a significant predictor of all four outcomes one year later, while Psycap predicted job and career satisfaction and career turnover intentions. Results provide a look into the worklife experiences of Canadian new graduate nurses over a one-year time period and identify factors that influence their job-related outcomes. These findings show that working conditions for new graduate nurses are generally

  7. Estimation of Catchment Transit Time in Fuji River Basin by using an improved Tank model

    Science.gov (United States)

    Wenchao, M.; Yamanaka, T.; Wakiyama, Y.; Wang, P.

    2013-12-01

    As an important parameter that reflects the characteristics of catchments, the catchment transit time (CTT) has been given much more widely attentions especially in recent years. The CTT is defined as the time water spends travelling through a catchment to the stream network [1], and it describes how catchments retain and release water and solutes and thus control geochemical and biogeochemical cycling and contamination persistence [2]. The objectives of the present study are to develop a new approach for estimating CTT without prior information on such TTD functions and to apply it to the Fuji River basin in the Central Japan Alps Region. In this study, an improved Tank model was used to compute mean CTT and TTD functions simultaneously. It involved water fluxes and isotope mass balance. Water storage capacity in the catchment, which strongly affects CTT, is reflected in isotope mass balance more sensitively than in water fluxes. A model calibrated with observed discharge and isotope data is used for virtual age tracer computation to estimate CTT. This model does not only consider the hydrological data and physical process of the research area but also reflects the actual TTD with considering the geological condition, land use and the other catchment-hydrological conditions. For the calibration of the model, we used river discharge record obtained by the Ministry of Land, Infrastructure and Transportation, and are collecting isotope data of precipitation and river waters monthly or semi-weekly. Three sub-catchments (SC1~SC3) in the Fuji River basin was selected to test the model with five layers: the surface layer, upper-soil layer, lower-soil layer, groundwater aquifer layer and bedrock layer (Layer 1- Layer 5). The evaluation of the model output was assessed using Nash-Sutcliffe efficiency (NSE), root mean square error-observations standard deviation ratio (RSR), and percent bias (PBIAS). Using long time-series of discharge records for calibration, the simulated

  8. Higher-order time-symmetry-breaking phase transition due to meeting of an exceptional point and a Fano resonance

    Science.gov (United States)

    Tanaka, Satoshi; Garmon, Savannah; Kanki, Kazuki; Petrosky, Tomio

    2016-08-01

    We have theoretically investigated the time-symmetry-breaking phase-transition process for two discrete states coupled with a one-dimensional continuum by solving the nonlinear eigenvalue problem for the effective Hamiltonian associated with the discrete spectrum. We obtain the effective Hamiltonian with use of the Feshbach-Brillouin-Wigner projection method. Strong energy dependence of the self-energy appearing in the effective Hamiltonian plays a key role in the time-symmetry-breaking phase transition: As a result of competition in the decay process between the Van Hove singularity and the Fano resonance, the phase transition becomes a higher-order transition when both the two discrete states are located near the continuum threshold.

  9. Estimation of Time-Varying Channel State Transition Probabilities for Cognitive Radio Systems by means of Particle Swarm Optimization

    Directory of Open Access Journals (Sweden)

    A. Akbulut

    2012-04-01

    Full Text Available In this study, Particle Swarm Optimization is applied for the estimation of the channel state transition probabilities. Unlike most other studies, where the channel state transition probabilities are assumed to be known and/or constant, in this study, these values are realistically considered to be time-varying parameters, which are unknown to the secondary users of the cognitive radio systems. The results of this study demonstrate the following: without any a priori information about the channel characteristics, even in a very transient environment, it is quite possible to achieve reasonable estimates of channel state transition probabilities with a practical and simple implementation.

  10. Colon-targeted quercetin delivery using natural polymer to enhance its bioavailability

    Directory of Open Access Journals (Sweden)

    Anil Singhal

    2011-01-01

    Full Text Available The aim of the present study is to develop a polymer (Guar Gum-based matrix tablet (using quercetin as a model drug with sufficient mechanical strength, and promising in vitro mouth-to-colon release profile. By definition, an oral colonic delivery system should retard drug release in the stomach and small intestine, and allow complete release in the colon. By drug delivery to the colon would therefore ensure direct treatment at the disease site, lower dosing, and fewer systemic side effects. Quercetin is antioxidant in nature and used to treat colon cancer, but they have poor absorption in the upper part of the gastrointestinal tract (GIT. As a site for drug delivery, the colon offers a near neutral pH, reduced digestive enzymatic activity, a long transit time, and an increased responsiveness to absorption enhancers. By achieving a colon-targeted drug delivery system, the absorption of quercetin may be increased, which leads to better bioactivity in fewer doses.

  11. Smart nanocomposite hydrogels based on azo crosslinked graphene oxide for oral colon-specific drug delivery

    Science.gov (United States)

    Hou, Lin; Shi, Yuyang; Jiang, Guixiang; Liu, Wei; Han, Huili; Feng, Qianhua; Ren, Junxiao; Yuan, Yujie; Wang, Yongchao; Shi, Jinjin; Zhang, Zhenzhong

    2016-08-01

    A safe and efficient nanocomposite hydrogel for colon cancer drug delivery was synthesized using pH-sensitive and biocompatible graphene oxide (GO) containing azoaromatic crosslinks as well as poly (vinyl alcohol) (PVA) (GO-N=N-GO/PVA composite hydrogels). Curcumin (CUR), an anti-cancer drug, was encapsulated successfully into the hydrogel through a freezing and thawing process. Fourier transform infrared spectroscopy, scanning electron microscopy and Raman spectroscopy were performed to confirm the formation and morphological properties of the nanocomposite hydrogel. The hydrogels exhibited good swelling properties in a pH-sensitive manner. Drug release studies under conditions mimicking stomach to colon transit have shown that the drug was protected from being released completely into the physiological environment of the stomach and small intestine. In vivo imaging analysis, pharmacokinetics and a distribution of the gastrointestinal tract experiment were systematically studied and evaluated as colon-specific drug delivery systems. All the results demonstrated that GO-N=N-GO/PVA composite hydrogels could protect CUR well while passing through the stomach and small intestine to the proximal colon, and enhance the colon-targeting ability and residence time in the colon site. Therefore, CUR loaded GO-N=N-GO/PVA composite hydrogels might potentially provide a theoretical basis for the treatment of colon cancer with high efficiency and low toxicity.

  12. Test MaxEnt in Social Strategy Transitions with Experimental Two-Person Constant Sum 2$\\times$2 Games

    CERN Document Server

    Xu, Bin

    2012-01-01

    By using laboratory experimental data, we test the uncertainty of social strategy transitions in various competing environments of fixed paired two-person constant sum $2 \\times 2$ games. It firstly shows that, the distributions of social strategy transitions are not erratic but obey the principle of the maximum entropy (MaxEnt). This finding indicates that human subject social systems and natural systems could have wider common backgrounds.

  13. Enzymatically Modified Starch Favorably Modulated Intestinal Transit Time and Hindgut Fermentation in Growing Pigs

    Science.gov (United States)

    Newman, M. A.; Zebeli, Q.; Velde, K.; Grüll, D.; Molnar, T.; Kandler, W.; Metzler-Zebeli, B. U.

    2016-01-01

    Aside from being used as stabilizing agents in many processed foods, chemically modified starches may act as functional dietary ingredients. Therefore, development of chemically modified starches that are less digestible in the upper intestinal segments and promote fermentation in the hindgut receives considerable attention. This study aimed to investigate the impact of an enzymatically modified starch (EMS) on nutrient flow, passage rate, and bacterial activity at ileal and post-ileal level. Eight ileal-cannulated growing pigs were fed 2 diets containing 72% purified starch (EMS or waxy cornstarch as control) in a cross-over design for 10 d, followed by a 4-d collection of feces and 2-d collection of ileal digesta. On d 17, solid and liquid phase markers were added to the diet to determine ileal digesta flow for 8 h after feeding. Reduced small intestinal digestion after the consumption of the EMS diet was indicated by a 10%-increase in ileal flow and fecal excretion of dry matter and energy compared to the control diet (Pfeeding reduced ileal transit time of both liquid and solid fractions compared to the control diet (P<0.05). The greater substrate flow to the large intestine with the EMS diet increased the concentrations of total and individual short-chain fatty acids (SCFA) in feces (P<0.05). Total bacterial 16S rRNA gene abundance was not affected by diet, whereas the relative abundance of the Lactobacillus group decreased (P<0.01) by 50% and of Enterobacteriaceae tended (P<0.1) to increase by 20% in ileal digesta with the EMS diet compared to the control diet. In conclusion, EMS appears to resemble a slowly digestible starch by reducing intestinal transit and increasing SCFA in the distal large intestine. PMID:27936165

  14. Estimation of cardiac output and pulmonary vascular resistance by contrast echocardiography transit time measurement: a prospective pilot study.

    Science.gov (United States)

    Choi, Brian G; Sanai, Reza; Yang, Benjamin; Young, Heather A; Mazhari, Ramesh; Reiner, Jonathan S; Lewis, Jannet F

    2014-10-31

    Studies with other imaging modalities have demonstrated a relationship between contrast transit and cardiac output (CO) and pulmonary vascular resistance (PVR). We tested the hypothesis that the transit time during contrast echocardiography could accurately estimate both CO and PVR compared to right heart catheterization (RHC). 27 patients scheduled for RHC had 2D-echocardiogram immediately prior to RHC. 3 ml of DEFINITY contrast followed by a 10 ml saline flush was injected, and a multi-cycle echo clip was acquired from the beginning of injection to opacification of the left ventricle. 2D-echo based calculations of CO and PVR along with the DEFINITY-based transit time calculations were subsequently correlated with the RHC-determined CO and PVR. The transit time from full opacification of the right ventricle to full opacification of the left ventricle inversely correlated with CO (r=-0.61, p<0.001). The transit time from peak opacification of the right ventricle to first appearance in the left ventricle moderately correlated with PVR (r=0.46, p<0.01). Previously described echocardiographic methods for the determination of CO (Huntsman method) and PVR (Abbas and Haddad methods) did not correlate with RHC-determined values (p = 0.20 for CO, p = 0.18 and p = 0.22 for PVR, respectively). The contrast transit time method demonstrated reliable intra- (p<0.0001) and inter-observer correlation (p<0.001). We describe a novel method for the quantification of CO and estimation of PVR using contrast echocardiography transit time. This technique adds to the methodologies used for noninvasive hemodynamic assessment, but requires further validation to determine overall applicability.

  15. 水通道蛋白3、4、8在大鼠慢传输型便秘模型结肠黏膜中的表达%Expression of aquaporin 3,4, and 8 in colonic mucosa of rat models with slow transit constipation

    Institute of Scientific and Technical Information of China (English)

    智会; 袁维堂

    2011-01-01

    Objective To investigate the expression of aquaporin 3, 4, and 8 in the colonic mucosa of rat models with slow transit constipation (STC). Methods STC rat model was established by giving the rats the compound solution of diphenoxylate. Real time polymerase chain reaction (RT-PCR) was used to measure the expression of aquaporin mRNA in colonic mucosa of STC rat models (study group,n= 16) and normal rats (control group,n=16). Cray scale ratio of aquaporin to β-action (internal reference) was used for quantification. Results RT-PCR revealed that the mean gray scale ratios of aquaporin 3 in the proximal colon of the study group and control group were 0.344 and 0.602 (P0.05), respectively. The mean gray scale ratios of aquaporin 4 in the proximal and the distal colon were 0.764 and 0.759 in the study group (P>0.05), and were 0.776 and 0.736 in the control group (P>0.05), respectively. However, there was no expression of aquaporin 8 in the proximal and the distal colon in either the study group or the control groups. Conclusions Expression of aquaporin 3 in the proximal colon of STC rat models is down-regulated, which regulates water absorption. There are no significant changes in the expressions of aquaporin 4 and 8.%目的 探讨水通道蛋白(AQP)3、4、8在大鼠慢传输型便秘(STC)模型中的表达情况.方法 利用复方地芬诺酯灌胃的方法建立大鼠STC模型,采用RT-PCR方法测定STC组(16只)及对照组大鼠(16只)升、降结肠黏膜的AQP3、4、8 mRNA表达情况.结果 STC组与对照组升结肠、降结肠AQP3平均相对表达量分别为0.344和0.602(P0.05);STC组和对照组升结肠、降结肠AQP4平均相对表达量分别为0.764和0.759(P>0.05)、0.776和0.736(P>0.05);AQP8在实验组和对照组升降结肠中未见明显表达.结论 AQP3在STC大鼠的升结肠黏膜中表达下调,对水吸收起调节作用;AQP4和AQP8的表达无明显变化.

  16. Transit Timing Observations from Kepler: II. Confirmation of Two Multiplanet Systems via a Non-parametric Correlation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Eric B.; /Florida U.; Fabrycky, Daniel C.; /Lick Observ.; Steffen, Jason H.; /Fermilab; Carter, Joshua A.; /Harvard-Smithsonian Ctr. Astrophys.; Fressin, Francois; /Harvard-Smithsonian Ctr. Astrophys.; Holman, Matthew J.; /Harvard-Smithsonian Ctr. Astrophys.; Lissauer, Jack J.; /NASA, Ames; Moorhead, Althea V.; /Florida U.; Morehead, Robert C.; /Florida U.; Ragozzine, Darin; /Harvard-Smithsonian Ctr. Astrophys.; Rowe, Jason F.; /NASA, Ames /SETI Inst., Mtn. View /San Diego State U., Astron. Dept.

    2012-01-01

    We present a new method for confirming transiting planets based on the combination of transit timing variations (TTVs) and dynamical stability. Correlated TTVs provide evidence that the pair of bodies are in the same physical system. Orbital stability provides upper limits for the masses of the transiting companions that are in the planetary regime. This paper describes a non-parametric technique for quantifying the statistical significance of TTVs based on the correlation of two TTV data sets. We apply this method to an analysis of the transit timing variations of two stars with multiple transiting planet candidates identified by Kepler. We confirm four transiting planets in two multiple planet systems based on their TTVs and the constraints imposed by dynamical stability. An additional three candidates in these same systems are not confirmed as planets, but are likely to be validated as real planets once further observations and analyses are possible. If all were confirmed, these systems would be near 4:6:9 and 2:4:6:9 period commensurabilities. Our results demonstrate that TTVs provide a powerful tool for confirming transiting planets, including low-mass planets and planets around faint stars for which Doppler follow-up is not practical with existing facilities. Continued Kepler observations will dramatically improve the constraints on the planet masses and orbits and provide sensitivity for detecting additional non-transiting planets. If Kepler observations were extended to eight years, then a similar analysis could likely confirm systems with multiple closely spaced, small transiting planets in or near the habitable zone of solar-type stars.

  17. Pulse transit time shows vascular changes caused by propofol in children.

    Science.gov (United States)

    Kang, Joo-Eun; Song, In-Kyung; Lee, Ji-Hyun; Hur, Min; Kim, Jin-Tae; Kim, Hee-Soo

    2015-08-01

    Pulse transit time (PTT) is the time that it takes for the arterial pulse pressure wave to travel from the aortic valve to the periphery. It is a simple noninvasive technique for evaluating vascular changes. This study investigated the vascular changes by propofol during the induction of anesthesia in pediatric patients with the measuring of PTT. Without premedication, 2 mg/kg of propofol was administered intravenously with monitoring of electrocardiogram (ECG) and photoplethysmograph (PPG) in 20 pediatric patients aged 3-7 years. The ECG and PPG data were obtained for 1 min before propofol injection (baseline PTT) and 2 min after administration of propofol in the operating room. The PTT was defined as the time interval from the R-wave on the ECG to the maximum upslope of the corresponding PPG. The PTT was calculated off-line after collecting the data. The mean baseline PTT was 166.2 ± 25.9 ms and maximum PTT after propofol injection was 315.9 ± 64.9 ms (the interval between injection and the peak was 17.3 ± 7.6 s). The PTT after the peak changed variously; most of the patients showed no plateau; the PTT decreased progressively after the peak. The PTT after propofol administration prolonged in short time and rapidly recovered toward to the baseline values in pediatric patients. In conclusion, the baseline PTT in children is shorter comparing with adults and the vasodilatory effect of propofol on the vessels as described by the PTT was rapid and the recovery was faster, although the response to propofol was more varied than in adults.

  18. Transitions and Time: Dissonance between Social and Political Aging in South Korea

    Directory of Open Access Journals (Sweden)

    Won Jee Cho

    2012-05-01

    Full Text Available This study explored multidimensional meanings related to “becoming old” for the young-old in South Korean society. Six persons aged 62 to 68 were interviewed in-depth. They chronologically, physically, and socially experienced the transition to old age at different times determined through “Hwan-Gap” (at age 60 and through current social policies that define entry into elderhood (at age 65. However, most did not psychologically accept their own aging as beginning at age 60 with “Hwan-Gap.” They reported that they were “forced” to become old at that time, even though they did not yet qualify for old age benefits provided by the South Korean government. In addition, they did not consider others’ perceptions of them as “old” as a psychological obstacle to defining themselves as young. Knowledge about young-old persons’ dissonance between their identities and sociopolitical views of entry into elderhood is important for understanding their experiences during the five-year gap between sociocultural entry into old age at age 60 and entry into the nationally defined elderhood at age 65.

  19. Improved pulse transit time estimation by system identification analysis of proximal and distal arterial waveforms.

    Science.gov (United States)

    Xu, Da; Ryan, Kathy L; Rickards, Caroline A; Zhang, Guanqun; Convertino, Victor A; Mukkamala, Ramakrishna

    2011-10-01

    We investigated the system identification approach for potentially improved estimation of pulse transit time (PTT), a popular arterial stiffness marker. In this approach, proximal and distal arterial waveforms are measured and respectively regarded as the input and output of a system. Next, the system impulse response is identified from all samples of the measured input and output. Finally, the time delay of the impulse response is detected as the PTT estimate. Unlike conventional foot-to-foot detection techniques, this approach is designed to provide an artifact robust estimate of the true PTT in the absence of wave reflection. The approach is also applicable to arbitrary types of arterial waveforms. We specifically applied a parametric system identification technique to noninvasive impedance cardiography (ICG) and peripheral arterial blood pressure waveforms from 15 humans subjected to lower-body negative pressure. We assessed the technique through the correlation coefficient (r) between its 1/PTT estimates and measured diastolic pressure (DP) per subject and the root mean squared error (RMSE) of the DP predicted from these estimates and measured DP. The technique achieved average r and RMSE values of 0.81 ± 0.16 and 4.3 ± 1.3 mmHg. For comparison, the corresponding values were 0.59 ± 0.37 (P system identification approach can indeed improve PTT estimation.

  20. Violation of the transit-time limit toward generation of ultrashort electron bunches with controlled velocity chirp

    Science.gov (United States)

    Jeon, Seok-Gy; Shin, Dongwon; Hur, Min Sup

    2016-09-01

    Various methods to generate ultrashort electron bunches for the ultrafast science evolved from the simple configuration of two-plate vacuum diodes to advanced technologies such as nanotips or photocathodes excited by femtosecond lasers. In a diode either in vacuum or of solid-state, the transit-time limit originating from finite electron mobility has caused spatiotemporal bunch-collapse in ultrafast regime. Here, we show for the first time that abrupt exclusion of transit-phase is a more fundamental origin of the bunch-collapse than the transit-time limit. We found that by significantly extending the cathode-anode gap distance, thereby violating the transit-time limit, the conventional transit-time-related upper frequency barrier in diodes can be removed. Furthermore, we reveal how to control the velocity chirp of bunches leading to ballistic bunch-compression. Demonstration of 0.707 THz-, 46.4 femtosecond-bunches from a 50 μm-wide diode in three-dimensional particle-in-cell simulations shows a way toward simple and compact sources of ultrafast electron bunches for diverse ultrafast sciences.

  1. Development of a real-time PCR method for the detection of bacterial colonization in rat models of severe acute pancreatitis

    Institute of Scientific and Technical Information of China (English)

    PENG Jun-sheng; LIU Zhong-hui; LI Chu-jun; WU Xiao-bin; DIAO De-chang; DU Yan-ping; CHEN Jun-rong; LI Yun; WANG Hua-she

    2010-01-01

    Background Techniques for the fast and accurate detection of bacterial infection are critical for early diagnosis, prevention and treatment of bacterial translocation in clinical severe acute pancreatitis (SAP). In this study, the availability of a real-time PCR method in detection of bacterial colonization in SAP rat models was investigated.Methods Samples of blood, mesenteric lymph nodes (MLN), pancreas and liver from 24 specific pathogen-free rats (8 in a control group, 16 in a SAP group) were detected for bacterial infection rates both by agar plate culture and a real-time PCR method, and the results were made contrast.Results Bacterial infection rates of the blood, MLN, pancreas and liver in the SAP group and the control group by the two different methods were almost the same, which were 5/16, 12/16, 15/16, 12/16 in the SAP group compared with 0/8, 1/8, 0/8, 0/8 in the control group by agar plate culture, while 5/16, 10/16, 13/16, 12/16 and 0/8, 1/8, 0/8, 0/8 respectively by a real-time PCR method. Bacterial number was estimated by real-time PCR, which showed that in the same mass of tissues, the pancreas contained more bacteria than the other three kinds of organs in SAP rats (P <0.01), that may be due to the edema, necrosis and hemorrhage existing in the pancreas, making it easier for bacteria to invade and breed.Conclusion Fast and accurate detection of bacterial translocation in SAP rat models could be carried out by a real-time PCR procedure.

  2. New BSN nurses' perspectives on the transition to practice in changing economic times.

    Science.gov (United States)

    Craig, Carol; Moscato, Susan; Moyce, Sally

    2012-04-01

    Helping nursing graduates transition to practice is a concern for nursing educators and employers. This article reports graduates' perceptions of transition both when jobs were plentiful and when jobs were scarce. Survey results from comparison of 2008 and 2010 graduates demonstrated few differences. Key indicators of successful transition were positive feedback at the work site, increased self-confidence on the part of the new graduate, and acceptance by the care team. Presence of good role models, ability to ask questions safely, and ongoing feedback on performance assisted successful transition.

  3. Characterization of the K2-19 Multiple-Transiting Planetary System via High-Dispersion Spectroscopy, AO Imaging, and Transit Timing Variations

    CERN Document Server

    Narita, Norio; Fukui, Akihiko; Hori, Yasunori; Sanchis-Ojeda, Roberto; Winn, Joshua N; Ryu, Tsuguru; Kusakabe, Nobuhiko; Kudo, Tomoyuki; Onitsuka, Masahiro; Delrez, Laetitia; Gillon, Michael; Jehin, Emmanuel; McCormac, James; Holman, Matthew; Izumiura, Hideyuki; Takeda, Yoichi; Tamura, Motohide; Yanagisawa, Kenshi

    2015-01-01

    K2-19 (EPIC201505350) is a unique planetary system in which two transiting planets with radii ~ 7 $R_{Earth}$ (inner planet b) and ~ 4 $R_{Earth}$ (outer planet c) have orbits that are nearly in a 3:2 mean-motion resonance. Here, we present results of ground-based follow-up observations for the K2-19 planetary system. We have performed high-dispersion spectroscopy and high-contrast adaptive-optics imaging of the host star with the HDS and HiCIAO on the Subaru 8.2m telescope. We find that the host star is relatively old (>8 Gyr) late G-type star ($T_{eff}$ ~ 5350 K, $M_s$ ~ 0.9 $M_{Sun}$, and $R_{s}$ ~ 0.9 $R_{Sun}$). We do not find any contaminating faint objects near the host star which could be responsible for (or dilute) the transit signals. We have also conducted transit follow-up photometry for the inner planet with KeplerCam on the FLWO 1.2m telescope, TRAPPISTCAM on the TRAPPIST 0.6m telescope, and MuSCAT on the OAO 1.88m telescope. We confirm the presence of transit-timing variations, as previously re...

  4. 12.4.Colon,rectum and anus

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930312 Test of colonic transit for the diagno-sis of constipation.LIU Shixin (刘世信),et al.Binjiang Hosp Tianjin,300022.Natl Med J China 1993;73(2)75—77.This study consists of the design of the ex-perimental markers for the colonic transit andthe application to clinical examination.Themarkers were displayed distinctly in the transittest.The study of clinical application showedthat colonic transit test is of diagnostic value inscreening patients with constipation.The indexof transit test,an authoritatively significant tar-get.has an imnortant valuta for the differential

  5. Comparison of efficacy of cryotherapy and chlorhexidine to oral nutrition transition time in chemotherapy-induced oral mucositis.

    Science.gov (United States)

    Erden, Y; Ipekcoban, G

    2016-05-01

    The aim of this study was to compare the efficacy of cryotherapy and chlorhexidine to oral nutrition transition time in chemotherapy-induced oral mucositis. This randomised controlled trial with random assignments to the experimental and control groups was conducted with cancer patients. Study data were collected from 90 cancer patients. The first experimental group (n = 30) received chlorhexidine mouthwash, the second experimental group (n = 30) received oral cryotherapy and the control group (n = 30) received routine care. To collect data we used the 'Mucositis Rating Index'. Changes in patients' oral mucosa in each group were checked and oral feeding transition periods were recorded. There was an important statistical difference between the times of transition to oral nutrition for patients (P < 0.01). Oral nutrition transition time of patients in the first experimental group who had applied chlorhexidine was shorter than in other groups. Following the tests, we detected a significant shortening in oral nutrition transition time of patients in first group who used chlorhexidine gargle as compared to the second group and control group. There was no significant difference between cryotherapy application and control group. In parallel with these findings, we detected that the degree of oral mucositis decreased.

  6. Communication: Transition state trajectory stability determines barrier crossing rates in chemical reactions induced by time-dependent oscillating fields.

    Science.gov (United States)

    Craven, Galen T; Bartsch, Thomas; Hernandez, Rigoberto

    2014-07-28

    When a chemical reaction is driven by an external field, the transition state that the system must pass through as it changes from reactant to product--for example, an energy barrier--becomes time-dependent. We show that for periodic forcing the rate of barrier crossing can be determined through stability analysis of the non-autonomous transition state. Specifically, strong agreement is observed between the difference in the Floquet exponents describing stability of the transition state trajectory, which defines a recrossing-free dividing surface [G. T. Craven, T. Bartsch, and R. Hernandez, "Persistence of transition state structure in chemical reactions driven by fields oscillating in time," Phys. Rev. E 89, 040801(R) (2014)], and the rates calculated by simulation of ensembles of trajectories. This result opens the possibility to extract rates directly from the intrinsic stability of the transition state, even when it is time-dependent, without requiring a numerically expensive simulation of the long-time dynamics of a large ensemble of trajectories.

  7. Transit Timing Variation Measurements of WASP-12b and Qatar-1b: No Evidence Of Additional Planets

    Science.gov (United States)

    Collins, Karen A.; Kielkopf, John F.; Stassun, Keivan G.

    2017-02-01

    WASP-12b and Qatar-1b are transiting hot Jupiters for which previous works have suggested the presence of transit timing variations (TTVs) indicative of additional bodies in these systems—an Earth-mass planet in WASP-12 and a brown-dwarf mass object in Qatar-1. Here, we present 23 new WASP-12b and 18 new Qatar-1b complete (or nearly complete) transit observations. We perform global system fits to all of our light curves for each system, as well as RV and stellar spectroscopic parameters from the literature. The global fits provide refined system parameters and uncertainties for each system, including precise transit center times for each transit. The transit model residuals of the combined and five minute binned light curves have an rms of 183 and 255 parts per million (ppm) for WASP-12b and Qatar-1b, respectively. Most of the WASP-12b system parameter values from this work are consistent with values from previous studies, but have ∼40%–50% smaller uncertainties. Most of the Qatar-1b system parameter values and uncertainties from this work are consistent with values recently reported in the literature. We find no convincing evidence for sinusoidal TTVs with a semi-amplitude of more than ∼35 and ∼25 s in the WASP-12b and Qatar-1b systems, respectively.

  8. Adolescents' Changing Future Expectations Predict the Timing of Adult Role Transitions

    Science.gov (United States)

    Beal, Sarah J.; Crockett, Lisa J.; Peugh, James

    2016-01-01

    Individual differences in the transition to adulthood are well established. This study examines the extent to which heterogeneity in pathways to adulthood that have been observed in the broader U.S. population are mirrored in adolescents' expectations regarding when they will experience key adult role transitions (e.g., marriage). Patterns of…

  9. Stochastic Stability for Time-Delay Markovian Jump Systems with Sector-Bounded Nonlinearities and More General Transition Probabilities

    Directory of Open Access Journals (Sweden)

    Dan Ye

    2013-01-01

    Full Text Available This paper is concerned with delay-dependent stochastic stability for time-delay Markovian jump systems (MJSs with sector-bounded nonlinearities and more general transition probabilities. Different from the previous results where the transition probability matrix is completely known, a more general transition probability matrix is considered which includes completely known elements, boundary known elements, and completely unknown ones. In order to get less conservative criterion, the state and transition probability information is used as much as possible to construct the Lyapunov-Krasovskii functional and deal with stability analysis. The delay-dependent sufficient conditions are derived in terms of linear matrix inequalities to guarantee the stability of systems. Finally, numerical examples are exploited to demonstrate the effectiveness of the proposed method.

  10. Kepler-9: A System of Multiple Planets Transiting a Sun-Like Star, Confirmed by Timing Variations

    Science.gov (United States)

    Holman, Matthew J.; Fabrycky, Daniel C.; Ragozzine, Darin; Ford, Eric B.; Steffen, Jason H.; Welsh, William F.; Lissauer, Jack J.; Latham, David W.; Marcy, Geoffrey W.; Walkowicz, Lucianne M.; Batalha, Natalie M.; Jenkins, Jon M.; Rowe, Jason F.; Cochran, William D.; Fressin, Francois; Torres, Guillermo; Buchhave, Lars A.; Sasselov, Dimitar D.; Borucki, William J.; Koch, David G.; Basri, Gibor; Brown, Timothy M.; Caldwell, Douglas A.; Charbonneau, David; Dunham, Edward W.; Gautier, Thomas N.; Geary, John C.; Gilliland, Ronald L.; Haas, Michael R.; Howell, Steve B.; Ciardi, David R.; Endl, Michael; Fischer, Debra; Fürész, Gábor; Hartman, Joel D.; Isaacson, Howard; Johnson, John A.; MacQueen, Phillip J.; Moorhead, Althea V.; Morehead, Robert C.; Orosz, Jerome A.

    2010-10-01

    The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection of two Saturn-size planets that transit the same Sun-like star, based on 7 months of Kepler observations. Their 19.2- and 38.9-day periods are presently increasing and decreasing at respective average rates of 4 and 39 minutes per orbit; in addition, the transit times of the inner body display an alternating variation of smaller amplitude. These signatures are characteristic of gravitational interaction of two planets near a 2:1 orbital resonance. Six radial-velocity observations show that these two planets are the most massive objects orbiting close to the star and substantially improve the estimates of their masses. After removing the signal of the two confirmed giant planets, we identified an additional transiting super-Earth-size planet candidate with a period of 1.6 days.

  11. Kepler-9: a system of multiple planets transiting a Sun-like star, confirmed by timing variations.

    Science.gov (United States)

    Holman, Matthew J; Fabrycky, Daniel C; Ragozzine, Darin; Ford, Eric B; Steffen, Jason H; Welsh, William F; Lissauer, Jack J; Latham, David W; Marcy, Geoffrey W; Walkowicz, Lucianne M; Batalha, Natalie M; Jenkins, Jon M; Rowe, Jason F; Cochran, William D; Fressin, Francois; Torres, Guillermo; Buchhave, Lars A; Sasselov, Dimitar D; Borucki, William J; Koch, David G; Basri, Gibor; Brown, Timothy M; Caldwell, Douglas A; Charbonneau, David; Dunham, Edward W; Gautier, Thomas N; Geary, John C; Gilliland, Ronald L; Haas, Michael R; Howell, Steve B; Ciardi, David R; Endl, Michael; Fischer, Debra; Fürész, Gábor; Hartman, Joel D; Isaacson, Howard; Johnson, John A; MacQueen, Phillip J; Moorhead, Althea V; Morehead, Robert C; Orosz, Jerome A

    2010-10-01

    The Kepler spacecraft is monitoring more than 150,000 stars for evidence of planets transiting those stars. We report the detection of two Saturn-size planets that transit the same Sun-like star, based on 7 months of Kepler observations. Their 19.2- and 38.9-day periods are presently increasing and decreasing at respective average rates of 4 and 39 minutes per orbit; in addition, the transit times of the inner body display an alternating variation of smaller amplitude. These signatures are characteristic of gravitational interaction of two planets near a 2:1 orbital resonance. Six radial-velocity observations show that these two planets are the most massive objects orbiting close to the star and substantially improve the estimates of their masses. After removing the signal of the two confirmed giant planets, we identified an additional transiting super-Earth-size planet candidate with a period of 1.6 days.

  12. Characterization of the K2-19 Multiple-transiting Planetary System via High-dispersion Spectroscopy, AO Imaging, and Transit Timing Variations

    Science.gov (United States)

    Narita, Norio; Hirano, Teruyuki; Fukui, Akihiko; Hori, Yasunori; Sanchis-Ojeda, Roberto; Winn, Joshua N.; Ryu, Tsuguru; Kusakabe, Nobuhiko; Kudo, Tomoyuki; Onitsuka, Masahiro; Delrez, Laetitia; Gillon, Michael; Jehin, Emmanuel; McCormac, J