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Sample records for dynamic cephalic containtment

  1. [External cephalic version].

    Science.gov (United States)

    Navarro-Santana, B; Duarez-Coronado, M; Plaza-Arranz, J

    2016-08-01

    To analyze the rate of successful external cephalic versions in our center and caesarean sections that would be avoided with the use of external cephalic versions. From January 2012 to March 2016 external cephalic versions carried out at our center, which were a total of 52. We collected data about female age, gestational age at the time of the external cephalic version, maternal body mass index (BMI), fetal variety and situation, fetal weight, parity, location of the placenta, amniotic fluid index (ILA), tocolysis, analgesia, and newborn weight at birth, minor adverse effects (dizziness, hypotension and maternal pain) and major adverse effects (tachycardia, bradycardia, decelerations and emergency cesarean section). 45% of the versions were unsuccessful and 55% were successful. The percentage of successful vaginal delivery in versions was 84% (4% were instrumental) and 15% of caesarean sections. With respect to the variables studied, only significant differences in birth weight were found; suggesting that birth weight it is related to the outcome of external cephalic version. Probably we did not find significant differences due to the number of patients studied. For women with breech presentation, we recommend external cephalic version before the expectant management or performing a cesarean section. The external cephalic version increases the proportion of fetuses in cephalic presentation and also decreases the rate of caesarean sections.

  2. Moxibustion for Cephalic Version of Breech Presentation.

    Science.gov (United States)

    Schlaeger, Judith M; Stoffel, Cynthia L; Bussell, Jeanie L; Cai, Hui Yan; Takayama, Miho; Yajima, Hiroyoshi; Takakura, Nobuari

    2018-05-01

    Moxibustion, a form of traditional Chinese medicine (TCM), is the burning of the herb moxa (Folium Artemisiae argyi or mugwort) over acupuncture points. It is often used in China to facilitate cephalic version of breech presentation. This article reviews the history, philosophy, therapeutic use, possible mechanisms of action, and literature pertaining to its use for this indication. For moxibustion, moxa can be rolled into stick form, placed directly on the skin, or placed on an acupuncture needle and ignited to warm acupuncture points. Studies have demonstrated that moxibustion may promote cephalic version of breech presentation and may facilitate external cephalic version. However, there is currently a paucity of research on the effects of moxibustion on cephalic version of breech presentation, and thus there is a need for further studies. Areas needing more investigation include efficacy, safety, optimal technique, and best protocol for cephalic version of breech presentation. © 2018 by the American College of Nurse-Midwives.

  3. Fetomaternal hemorrhage during external cephalic version.

    Science.gov (United States)

    Boucher, Marc; Marquette, Gerald P; Varin, Jocelyne; Champagne, Josette; Bujold, Emmanuel

    2008-07-01

    To estimate the frequency and volume of fetomaternal hemorrhage during external cephalic version for term breech singleton fetuses and to identify risk factors involved with this complication. A prospective observational study was performed including all patients undergoing a trial of external cephalic version for a breech presentation of at least 36 weeks of gestation between 1987 and 2001 in our center. A search for fetal erythrocytes using the standard Kleihauer-Betke test was obtained before and after each external cephalic version. The frequency and volume of fetomaternal hemorrhage were calculated. Putative risk factors for fetomaternal hemorrhage were evaluated by chi(2) test and Mann-Whitney U test. A Kleihauer-Betke test result was available before and after 1,311 trials of external cephalic version. The Kleihauer-Betke test was positive in 67 (5.1%) before the procedure. Of the 1,244 women with a negative Kleihauer-Betke test before external cephalic version, 30 (2.4%) had a positive Kleihauer-Betke test after the procedure. Ten (0.8%) had an estimated fetomaternal hemorrhage greater than 1 mL, and one (0.08%) had an estimated fetomaternal hemorrhage greater than 30 mL. The risk of fetomaternal hemorrhage was not influenced by parity, gestational age, body mass index, number of attempts at version, placental location, or amniotic fluid index. The risk of detectable fetomaternal hemorrhage during external cephalic version was 2.4%, with fetomaternal hemorrhage more than 30 mL in less than 0.1% of cases. These data suggest that the performance of a Kleihauer-Betke test is unwarranted in uneventful external cephalic version and that in Rh-negative women, no further Rh immune globulin is necessary other than the routine 300-microgram dose at 28 weeks of gestation and postpartum. II.

  4. Cephalic Tetanus from Penetrating Orbital Wound

    Directory of Open Access Journals (Sweden)

    Eloïse Guyennet

    2009-01-01

    Full Text Available Tetanus is a neurologic disorder caused by tetanospasmin, a protein toxin elaborated by Clostridium tetani. Cephalic tetanus is a localized form of the disease causing trismus and dysfunction of cranial nerves. We report the case of a man who presented with facial trauma, complete ophthalmoplegia, exophthalmos, areactive mydriasis, and periorbital hematoma. An orbital CT revealed air bubbles in the right orbital apex. The patient was given a tetanus toxoid booster and antibiotherapy. After extraction of a wooden foreign body, the patient developed right facial nerve palsy, disorders of swallowing, contralateral III cranial nerve palsy, and trismus. Only one case of cephalic tetanus from penetrating orbital wound has been reported in literature 20 years ago. When a patient presents with an orbital wound with ophthalmoplegia and signs of anaerobic infection, cephalic tetanus should be ruled out.

  5. Head phenotypes based on cephalic index among Ukwuani people ...

    African Journals Online (AJOL)

    ... between cephalic index and age. There is no significant difference between cephalic indices at 6-12 years and 13-19 years. There exist statistically significant differences between cephalic index at 20 years and above, and at 6-12 years and 13-19 years. Conclusion: This is relevant in anthropology and forensic science.

  6. Labour Outcomes After Successful External Cephalic Version Compared With Spontaneous Cephalic Version.

    Science.gov (United States)

    Krueger, Samantha; Simioni, Julia; Griffith, Lauren E; Hutton, Eileen K

    2018-01-01

    This study sought to compare obstetrical outcomes for women with a cephalic presentation at birth resulting from successful external cephalic version (ECV) compared to those resulting from spontaneous cephalic version (SCV). Secondary analysis was performed on Early External Cephalic Version Trial data. A total of 931 study participants had breech presentations between 34 and 36 weeks' gestation and cephalic presentations at birth. The incidence of intrapartum interventions was compared between patients with successful ECV (557) and those with SCV (374). A generalized linear mixed model was used to determine ORs for our primary outcomes. Parity, maternal BMI, previous CS, and enrolment centre were controlled for in the analysis. No differences were found after ECV compared with SCV in the incidence of CS (96 of 557 and 76 of 374, respectively; adjusted OR [aOR] 0.89; 95% CI 0.63-1.26), instrumental birth (68 of 557 and 29 of 373, respectively; aOR 1.55; 95% CI 0.96-2.50), or normal vaginal birth (393 of 557 and 268 of 373, respectively; aOR 0.92; 95% CI 0.68-1.24). Multiparous women with successful ECV were half as likely to require a CS compared with those with SCV and no ECV (28 of 313 and 42 of 258, respectively; aOR 0.45; 95% CI 0.26-0.80). This is the first study to compare birth outcomes of breech pregnancies that convert to cephalic presentation by means of SCV with birth outcomes of breech pregnancies that have ECV. Women with a cephalic-presenting fetus at birth as a result of successful ECV are not at greater risk of obstetrical interventions at birth when compared with women with fetuses who spontaneously turn to a cephalic presentation in the third trimester. Copyright © 2018. Published by Elsevier Inc.

  7. Mode of delivery following successful external cephalic version: comparison with spontaneous cephalic presentations at delivery.

    Science.gov (United States)

    Kuppens, Simone M I; Hutton, Eileen K; Hasaart, Tom H M; Aichi, Nassira; Wijnen, Henrica A; Pop, Victor J M

    2013-10-01

    To compare the obstetric outcomes of pregnant women after successful external cephalic version (ECV) (cases) with a large group of pregnant women with a spontaneously occurring cephalic fetal position at delivery (controls). We conducted a retrospective matched cohort study in a teaching hospital in the Netherlands. Delivery outcomes of women with a successful ECV were compared with those of women with spontaneously occurring cephalic presentations, controlling for maternal age, parity, gestational age at delivery, and onset of labour (spontaneous or induced). Exclusion criteria were a history of Caesarean section, delivery at < 35 weeks, and elective Caesarean section. The primary outcome was the prevalence of Caesarean section and instrumental delivery in both groups; secondary outcomes were the characteristics of cases requiring intervention such as Caesarean section or instrumental delivery. Women who had a successful ECV had a significantly higher Caesarean section rate than the women in the control group (33/220 [15%] vs. 62/1030 [6.0 %]; P < 0.001). There was no difference in the incidence of instrumental delivery (20/220 [9.1%] vs. 103/1030 [10%]). Comparison of characteristics of women in the cases group showed that nulliparity, induction of labour, and occiput posterior presentation were associated with Caesarean section and instrumental deliveries. Compared with delivery of spontaneous cephalic presenta-tions, delivery of cephalic presenting babies following successful ECV is associated with an increased rate of Caesarean section, especially in nulliparous women and women whose labour is induced.

  8. Cephalic version by moxibustion for breech presentation.

    Science.gov (United States)

    Coyle, Meaghan E; Smith, Caroline A; Peat, Brian

    2012-05-16

    Moxibustion (a type of Chinese medicine which involves burning a herb close to the skin) to the acupuncture point Bladder 67 (BL67) (Chinese name Zhiyin), located at the tip of the fifth toe, has been proposed as a way of correcting breech presentation. To examine the effectiveness and safety of moxibustion on changing the presentation of an unborn baby in the breech position, the need for external cephalic version (ECV), mode of birth, and perinatal morbidity and mortality for breech presentation. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (26 March 2012), MEDLINE (1966 to 1 August 2011), EMBASE (1980 to August 2011), CINAHL (1982 to 1 August 2011), MIDIRS (1982 to 1 August 2011) and AMED (1985 to 1 August 2011) and searched bibliographies of relevant papers. The inclusion criteria were published and unpublished randomised controlled trials comparing moxibustion (either alone or in combination with acupuncture or postural techniques) with a control group (no moxibustion), or other methods (e.g. external cephalic version, acupuncture, postural techniques) in women with a singleton breech presentation. Two review authors independently assessed eligibility and trial quality and extracted data. The outcome measures were baby's presentation at birth, need for external cephalic version, mode of birth, perinatal morbidity and mortality, maternal complications and maternal satisfaction, and adverse events. Six new trials have been added to this updated review. One trial has been moved to studies awaiting classification while further data are being requested. This updated review now includes a total of eight trials (involving 1346 women). Meta-analyses were undertaken (where possible) for the main and secondary outcomes. Moxibustion was not found to reduce the number of non-cephalic presentations at birth compared with no treatment (P = 0.45). Moxibustion resulted in decreased use of oxytocin before or during labour for women who had vaginal

  9. Anesthetic management of external cephalic version.

    Science.gov (United States)

    Chalifoux, Laurie A; Sullivan, John T

    2013-09-01

    Breech presentation is common at term and its reduction through external cephalic version represents a noninvasive opportunity to avoid cesarean delivery and the associated maternal morbidity. In addition to uterine relaxants, neuraxial anesthesia is associated with increased success of version procedures when surgical anesthetic dosing is used. The intervention is likely cost effective given the effect size and the avoided high costs of cesarean delivery. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Analgesia/anesthesia for external cephalic version.

    Science.gov (United States)

    Weiniger, Carolyn F

    2013-06-01

    Professional society guidelines recommend that women with breech presentation be delivered surgically due to a higher incidence of fetal risks compared with vaginal delivery. An alternative is attempted external cephalic version, which if successful, enables attempted vaginal delivery. Attitudes towards external cephalic version (ECV) will be considered in this review, along with pain relief methods and their impact on ECV success rates. Articles suggest that ECV is infrequently offered, due to both physician and patient factors. Success of ECV is higher in multiparous women, complete breech, posterior placenta, or smaller fetus. Preterm ECV performance does not increase vaginal delivery rates. Neuraxial techniques (spinal or epidural) significantly increase ECV success rates, as do moxibustion and hypnosis. Four reviews summarized studies considering ECV and neuraxial techniques. These reviews suggest that neuraxial techniques using high (surgical) doses of local anesthetic are efficacious compared with control groups not using anesthesia, whereas techniques using low-doses are not. Low-dose versus high-dose neuraxial analgesia/anesthesia has not been directly compared in a single study. Based on currently available data, the rate of cephalic presentation is not increased using neuraxial techniques, but vaginal delivery rates are higher. ECV appears to be a low-risk procedure. The logistics of routine ECV and provision of optimal neuraxial techniques for successful ECV require additional research. Safety aspects of neuraxial anesthesia for ECV require further investigation.

  11. Tocolysis in term breech external cephalic version.

    Science.gov (United States)

    Nor Azlin, M I; Haliza, H; Mahdy, Z A; Anson, I; Fahya, M N; Jamil, M A

    2005-01-01

    To study the effect of ritodrine tocolysis on the success of external cephalic version (ECV) and to assess the role of ECV in breech presentation at our centre. A prospective randomized double-blind-controlled trial comparing ritodrine and placebo in ECV of singleton term breech pregnancy at a tertiary hospital. Among the 60 patients who were recruited, there was a success rate of 36.7%. Ritodrine tocolysis significantly improved the success rate of ECV (50% vs. 23%; P=0.032). There was a marked effect of ritodrine tocolysis on the ECV success in nulliparae (36.4% vs. 13.0%) and multiparae (87.5% vs. 57.1%). External cephalic version has shown to reduce the rate of cesarean section for breech presentation by 33.5% in our unit. External cephalic version significantly reduced the rate of cesarean section in breech presentation, and ritodrine tocolysis improved the success of ECV and should be offered to both nulliparous and parous women in the case of term breech presentation.

  12. Pancreatico-gastric Anastomosis Following Cephalic Duodenopancreatectomy: New Perspectives

    Directory of Open Access Journals (Sweden)

    Tudor A

    2015-09-01

    Full Text Available Introduction. Although in recent years there have been various versions of pancreatic - digestive reconstruction after cephalic duodenopancreatectomy, this issue is still highly debated.

  13. [External cephalic version of breech presentation at term].

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    Albrechtsen, Susanne; Berge, Lillian N; Børdahl, Per E; Egeland, Thore; Henriksen, Tore; Håheim, Lise Lund; Øian, Pål

    2005-03-03

    External cephalic version could be an alternative to either vaginal delivery or caesarean section in breech presentation at term. A systematic literature review about external cephalic version in breech presentation. The numbers of breech presentation delivered by caesarean section could probably be reduced in Norway by offering version, but this would not affect perinatal mortality.

  14. External cephalic version before elective caesarean section for breech presentation

    International Nuclear Information System (INIS)

    Zafar, F.; Sanusi, A.

    2008-01-01

    The Royal College of Obstetrics and Gynaecology guidelines state that all uncomplicated breech Presentation should be offered external cephalic version and all such women should be briefed about the risks and benefits of external cephalic version and all such women should be briefed about the risks and benefits of external cephalic version before undertaking the procedure. To ascertain the acceptability of external cephalic version before elective caesarean section for breech Presentation by pregnant ladies and see whether they were adequately informed about the risks and benefits. The clinical audit was registered with the audit department at Watford general hospital and written Consent for the access of medical records was obtained. A retrospective view of 86 accessible medical records out of Total 110 elective breech caesarean sections was done over a period of one year. This retrospective study was conducted at the gynaecology and obstetrics department at Watford general hospital, Watford United Kingdom. Written consent for the access of medical records was obtained. All women who under went elective caesarean section due to breech presentation were included in the study. Out of a total of 110 elective breech caesarean sections performed, the data on 86 cases was selected for the final analysis. The information gathered included patient's profile, whether patient was informed of risks and benefits of external cephalic version, recognition of obstetric risk factors, external cephalic version performed and its success. Out of total 86 caesarean sections 46 were suitable for external cephalic version of whom 37 cases were offered external cephalic version. Among 37 patients who were offered external cephalic version only 15 patients accepted (22 declined) the procedure. Moreover, it was found that the documentation of risk/benefit explanation of the procedure was inadequate. External cephalic version was not successful in any of the patient. Causes for

  15. Practice Bulletin No. 161: External Cephalic Version.

    Science.gov (United States)

    2016-02-01

    In the United States, there is a widespread belief that the overall cesarean delivery rate is higher than necessary. Efforts are being directed toward decreasing the number of these procedures, in part by encouraging physicians to make changes in their management practices. Because breech presentations are associated with a high rate of cesarean delivery, there is renewed interest in techniques such as external cephalic version (ECV) and vaginal breech delivery. The purpose of this document is to provide information about ECV by summarizing the relevant evidence presented in published studies and to make recommendations regarding its use in obstetric practice.

  16. Introducing external cephalic version in a Malaysian setting.

    Science.gov (United States)

    Yong, Stephen P Y

    2007-02-01

    To assess the outcome of external cephalic version for routine management of malpresenting foetuses at term. Prospective observational study. Tertiary teaching hospital, Malaysia. From September 2003 to June 2004, a study involving 41 pregnant women with malpresentation at term was undertaken. An external cephalic version protocol was implemented. Data were collected for identifying characteristics associated with success or failure of external cephalic version. Maternal and foetal outcome measures including success rate of external cephalic version, maternal and foetal complications, and characteristics associated with success or failure; engagement of presenting part, placental location, direction of version, attempts at version, use of intravenous tocolytic agent, eventual mode of delivery, Apgar scores, birth weights, and maternal satisfaction with the procedure. Data were available for 38 women. External cephalic version was successful in 63% of patients; the majority (75%) of whom achieved a vaginal delivery. Multiparity (odds ratio=34.0; 95% confidence interval, 0.67-1730) and high amniotic fluid index (4.9; 1.3-18.2) were associated with successful external cephalic version. Engagement of presenting part (odds ratio=0.0001; 95% confidence interval, 0.00001-0.001) and a need to resort to backward somersault (0.02; 0.00001-0.916) were associated with poor success rates. Emergency caesarean section rate for foetal distress directly resulting from external cephalic version was 8%, but there was no perinatal or maternal adverse outcome. The majority (74%) of women were satisfied with external cephalic version. External cephalic version has acceptable success rates. Multiparity, liquor volume, engagement of presenting part, and the need for backward somersault were strong predictors of outcome. External cephalic version is relatively safe, simple to learn and perform, and associated with maternal satisfaction. Modern obstetric units should routinely offer the

  17. Neuraxial blockade for external cephalic version: Cost analysis.

    Science.gov (United States)

    Yamasato, Kelly; Kaneshiro, Bliss; Salcedo, Jennifer

    2015-07-01

    Neuraxial blockade (epidural or spinal anesthesia/analgesia) with external cephalic version increases the external cephalic version success rate. Hospitals and insurers may affect access to neuraxial blockade for external cephalic version, but the costs to these institutions remain largely unstudied. The objective of this study was to perform a cost analysis of neuraxial blockade use during external cephalic version from hospital and insurance payer perspectives. Secondarily, we estimated the effect of neuraxial blockade on cesarean delivery rates. A decision-analysis model was developed using costs and probabilities occurring prenatally through the delivery hospital admission. Model inputs were derived from the literature, national databases, and local supply costs. Univariate and bivariate sensitivity analyses and Monte Carlo simulations were performed to assess model robustness. Neuraxial blockade was cost saving to both hospitals ($30 per delivery) and insurers ($539 per delivery) using baseline estimates. From both perspectives, however, the model was sensitive to multiple variables. Monte Carlo simulation indicated neuraxial blockade to be more costly in approximately 50% of scenarios. The model demonstrated that routine use of neuraxial blockade during external cephalic version, compared to no neuraxial blockade, prevented 17 cesarean deliveries for every 100 external cephalic versions attempted. Neuraxial blockade is associated with minimal hospital and insurer cost changes in the setting of external cephalic version, while reducing the cesarean delivery rate. © 2015 The Authors. Journal of Obstetrics and Gynaecology Research © 2015 Japan Society of Obstetrics and Gynecology.

  18. Intravenous nitroglycerin for external cephalic version: a randomized controlled trial.

    Science.gov (United States)

    Hilton, Jennifer; Allan, Bruce; Swaby, Cheryl; Wahba, Raouf; Wah, Raouf; Jarrell, John; Wood, Stephen; Ross, Sue; Tran, Quynh

    2009-09-01

    To estimate whether treatment with intravenous nitroglycerin for uterine relaxation increases the chance of successful external cephalic version. Two double-blind, randomized clinical trials were undertaken: one in nulliparous women and a second in multiparous women. Women presenting for external cephalic version at term were eligible to participate. The primary outcome was immediate success of external cephalic version. Other outcomes were presentation at delivery, cesarean delivery rate, and side effects and complications. Sample size calculations were based on a 100% increase in success of external cephalic version with a one-sided analysis and alpha=0.05 (80% power). In total, 126 women were recruited-82 in the nulliparous trial and 44 in the multiparous trial. Seven patients did not have external cephalic version before delivery but were included in the analysis of success of external cephalic version. One patient was lost to follow-up. The external cephalic version success rate for nulliparous patients was 24% (10 of 42) in patients who received nitroglycerin compared with 8% (3 of 40) in those who receive placebo (P=.04, one-sided Fisher exact test, odds ratio 3.85, lower bound 1.22). In multiparous patients, the external cephalic version success rate did not differ significantly between groups: 44% (10 of 23) in the nitroglycerin group compared with 43% (9 of 21) in the placebo group (P=.60). Treatment with intravenous nitroglycerin increased the rate of successful external cephalic version in nulliparous, but not in multiparous, women. Treatment with intravenous nitroglycerin appeared to be safe, but our numbers were too small to rule out rare serious adverse effects. I.

  19. Obesity-related complications in Danish single cephalic term pregnancies

    DEFF Research Database (Denmark)

    Rode, Line; Nilas, Lisbeth; Wøjdemann, Karen

    2005-01-01

    OBJECTIVE: Our objective was to investigate the relationship between prepregnancy and obstetric body mass index (BMI) as well as fetal complications in a large, unselected cohort of Danish women with single cephalic pregnancies. METHODS: A cohort of 8,092 women from the Copenhagen First Trimester...... with an increasing prepregnancy BMI in women with single cephalic term pregnancies, particularly in nulliparous women....... Study with a registered prepregnancy BMI and a single cephalic term delivery were stratified into 3 BMI groups: normal weight (BMI /= 30 kg/m(2)). The effects of BMI and parity on the outcome were analyzed using multivariate logistic...

  20. Cephalic Tetanus in an Immunized Teenager: An Unusual Case Report.

    Science.gov (United States)

    Felter, Robert A; Zinns, Lauren E

    2015-07-01

    Tetanus is a rare disease in developed countries but is prevalent worldwide. It has significant morbidity and mortality. The causative agent Clostridium tetani is ubiquitous in nature. In the United States, approximately 50 to 100 cases are reported per year but rarely in immunocompetent, fully immunized patients. Of the four types of tetanus (generalized, neonatal, cephalic, and localized), cephalic is the least common. We present a case of cephalic tetanus in a 14-year-old boy who completed his primary immunizations with a video of his physical examination findings.

  1. Patterns of cephalic indexes in three West African populations

    African Journals Online (AJOL)

    USER

    Key words: Cephalic, mesocephalic, gender, culture, West Africa. INTRODUCTION ..... The biology of human adaptability, Oxford. University Press, Oxford, pp. ... Development and Evolution of Brain Size, Hahn, Jensen and. Brududec (eds) ...

  2. External cephalic version facilitation for breech presentation at term.

    Science.gov (United States)

    Hofmeyr, G J

    2001-01-01

    Tocolytic drugs to relax the uterus as well as other methods have been also used in an attempt to facilitate external cephalic version at term. The objective of this review is to assess the effects of routine tocolysis, fetal acoustic stimulation, epidural or spinal analgesia and transabdominal amnioinfusion for external cephalic version at term on successful version and measures of pregnancy outcome. The Cochrane Pregnancy and Childbirth Group Trials Register and the Cochrane Controlled Trials Register were searched. Date of last search: April 2001. Randomised and quasi-randomised trials comparing routine versus selective tocolysis; fetal acoustic stimulation in midline fetal spine positions versus dummy or no stimulation; epidural or spinal analgesia versus no regional analgesia; or transabdominal amnioinfusion versus no amnioinfusion for external cephalic version at term. Eligibility and trial quality were assessed by the reviewer. In seven trials, routine tocolysis was associated with fewer failures of external cephalic version (relative risk 0.74, 95% confidence interval 0.64 to 0.87). There were no significant differences between non-cephalic presentations at birth. Caesarean sections were reduced (relative risk 0.85, confidence interval 0.72-0.99). Fetal acoustic stimulation in midline fetal spine positions was associated with fewer failures of external cephalic version at term (relative risk 0.17, 95% confidence interval 0.05 to 0.60). With epidural or spinal analgesia, external cephalic version failure, non-cephalic births and caesarean sections were reduced in one trial but not the other. The overall differences were not statistically significant. No randomised trials of transabdominal amnioinfusion for external cephalic version at term were located. Routine tocolysis appears to reduce the failure rate of external cephalic version at term. Although promising, there is not enough evidence to evaluate the use of fetal acoustic stimulation in midline fetal

  3. Neuraxial blockade for external cephalic version: a systematic review.

    Science.gov (United States)

    Sultan, P; Carvalho, B

    2011-10-01

    The desire to decrease the number of cesarean deliveries has renewed interest in external cephalic version. The rationale for using neuraxial blockade to facilitate external cephalic version is to provide abdominal muscular relaxation and reduce patient discomfort during the procedure, so permitting successful repositioning of the fetus to a cephalic presentation. This review systematically examined the current evidence to determine the safety and efficacy of neuraxial anesthesia or analgesia when used for external cephalic version. A systematic literature review of studies that examined success rates of external cephalic version with neuraxial anesthesia was performed. Published articles written in English between 1945 and 2010 were identified using the Medline, Cochrane, EMBASE and Web of Sciences databases. Six, randomized controlled studies were identified. Neuraxial blockade significantly improved the success rate in four of these six studies. A further six non-randomized studies were identified, of which four studies with control groups found that neuraxial blockade increased the success rate of external cephalic version. Despite over 850 patients being included in the 12 studies reviewed, placental abruption was reported in only one patient with a neuraxial block, compared with two in the control groups. The incidence of non-reassuring fetal heart rate requiring cesarean delivery in the anesthesia groups was 0.44% (95% CI 0.15-1.32). Neuraxial blockade improved the likelihood of success during external cephalic version, although the dosing regimen that provides optimal conditions for successful version is unclear. Anesthetic rather than analgesic doses of local anesthetics may improve success. The findings suggest that neuraxial blockade does not compromise maternal or fetal safety during external cephalic version. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

  4. External cephalic version-related risks: a meta-analysis.

    Science.gov (United States)

    Grootscholten, Kim; Kok, Marjolein; Oei, S Guid; Mol, Ben W J; van der Post, Joris A

    2008-11-01

    To systematically review the literature on external cephalic version-related complications and to assess if the outcome of a version attempt is related to complications. In March 2007 we searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials. Studies reporting on complications from an external cephalic version attempt for singleton breech pregnancies after 36 weeks of pregnancy were selected. We calculated odds ratios (ORs) from studies that reported both on complications as well as on the position of the fetus immediately after the procedure. We found 84 studies, reporting on 12,955 version attempts that reported on external cephalic version-related complications. The pooled complication rate was 6.1% (95% CI 4.7-7.8), 0.24% for serious complications (95% confidence interval [CI] 0.17-0.34) and 0.35% for emergency cesarean deliveries (95% CI 0.26-0.47). Complications were not related to external cephalic version outcome (OR 1.2 (95% CI 0.93-1.7). External cephalic version is a safe procedure. Complications are not related to the fetal position after external cephalic version.

  5. External cephalic version experiences in Korea.

    Science.gov (United States)

    Kim, Mi-Young; Park, Min-Young; Kim, Gwang Jun

    2016-03-01

    The aim of this study was to evaluate obstetric outcomes of external cephalic version (ECV) performed at or near term. Single pregnant woman with breech presentation at or near term (n=145), who experienced ECV by one obstetrician from November 2009 to July 2014 in our institution were included in the study. Maternal baseline characteristic and fetal ultrasonographic variables were checked before the procedure. After ECV, the delivery outcomes of the women were gathered. Variables affecting the success or failure of ECV were evaluated. Success rate of ECV was 71.0% (n=103). Four variables (parity, amniotic fluid index, fetal spine position and rotational direction) were observed to be in correlation with success or failure of ECV. In contactable 83 individuals experienced successful ECV, cesarean delivery rates were 18.1%, 28.9%, and 5.3% in total, nulliparas, and multiparas, respectively. Based on the results, ECV is proposed to be safe for both mother and her fetus. In addition, it is a valuable procedure that increases probability of vaginal delivery for women with breech presentation.

  6. External cephalic version experiences in Korea

    Science.gov (United States)

    Kim, Mi-Young; Park, Min-Young

    2016-01-01

    Objective The aim of this study was to evaluate obstetric outcomes of external cephalic version (ECV) performed at or near term. Methods Single pregnant woman with breech presentation at or near term (n=145), who experienced ECV by one obstetrician from November 2009 to July 2014 in our institution were included in the study. Maternal baseline characteristic and fetal ultrasonographic variables were checked before the procedure. After ECV, the delivery outcomes of the women were gathered. Variables affecting the success or failure of ECV were evaluated. Results Success rate of ECV was 71.0% (n=103). Four variables (parity, amniotic fluid index, fetal spine position and rotational direction) were observed to be in correlation with success or failure of ECV. In contactable 83 individuals experienced successful ECV, cesarean delivery rates were 18.1%, 28.9%, and 5.3% in total, nulliparas, and multiparas, respectively. Conclusion Based on the results, ECV is proposed to be safe for both mother and her fetus. In addition, it is a valuable procedure that increases probability of vaginal delivery for women with breech presentation. PMID:27004197

  7. Amnioinfusion to facilitate external cephalic version after initial failure.

    Science.gov (United States)

    Adama van Scheltema, P N; Feitsma, A H; Middeldorp, J M; Vandenbussche, F P H A; Oepkes, D

    2006-09-01

    To evaluate the effectiveness of antepartum transabdominal amnioinfusion to facilitate external cephalic version after initial failure. Women with a structurally normal fetus in breech lie at term, with a failed external cephalic version and an amniotic fluid index (AFI) less than 15 cm, were asked to participate in our study. After tocolysis with indomethacin, a transabdominal amnioinfusion was performed with an 18G spinal needle. Lactated Ringers solution was infused until the AFI reached 15 cm, with a maximum of 1 L. External cephalic version was performed directly afterward. Seven women participated in the study. The gestational age of the women was between 36(+4) and 38(+3) weeks, and three women were primiparous. The AFI ranged from 4 cm to 13 cm. A median amount of 1,000 mL Ringers solution (range 700-1,000 mL) was infused per procedure. The repeat external cephalic versions after amnioinfusion were not successful in any of the patients. In our experience, amnioinfusion does not facilitate external cephalic version.

  8. Predictors of success of external cephalic version and cephalic presentation at birth among 1253 women with non-cephalic presentation using logistic regression and classification tree analyses.

    Science.gov (United States)

    Hutton, Eileen K; Simioni, Julia C; Thabane, Lehana

    2017-08-01

    Among women with a fetus with a non-cephalic presentation, external cephalic version (ECV) has been shown to reduce the rate of breech presentation at birth and cesarean birth. Compared with ECV at term, beginning ECV prior to 37 weeks' gestation decreases the number of infants in a non-cephalic presentation at birth. The purpose of this secondary analysis was to investigate factors associated with a successful ECV procedure and to present this in a clinically useful format. Data were collected as part of the Early ECV Pilot and Early ECV2 Trials, which randomized 1776 women with a fetus in breech presentation to either early ECV (34-36 weeks' gestation) or delayed ECV (at or after 37 weeks). The outcome of interest was successful ECV, defined as the fetus being in a cephalic presentation immediately following the procedure, as well as at the time of birth. The importance of several factors in predicting successful ECV was investigated using two statistical methods: logistic regression and classification and regression tree (CART) analyses. Among nulliparas, non-engagement of the presenting part and an easily palpable fetal head were independently associated with success. Among multiparas, non-engagement of the presenting part, gestation less than 37 weeks and an easily palpable fetal head were found to be independent predictors of success. These findings were consistent with results of the CART analyses. Regardless of parity, descent of the presenting part was the most discriminating factor in predicting successful ECV and cephalic presentation at birth. © 2017 Nordic Federation of Societies of Obstetrics and Gynecology.

  9. Antepartum transabdominal amnioinfusion to facilitate external cephalic version after initial failure.

    Science.gov (United States)

    Benifla, J L; Goffinet, F; Darai, E; Madelenat, P

    1994-12-01

    Transabdominal amnioinfusion can be used to facilitate external cephalic version. Our technique involves filling the uterine cavity with 700 or 900 mL of 37C saline under continuous echographic monitoring. External cephalic version is done the next morning. We have used this procedure in six women, all of whom had previous unsuccessful attempts at external cephalic version. After amnioinfusion, all six patients were converted to cephalic presentation and delivered normally, without obstetric or neonatal complications.

  10. Synaptic dimorphism in Onychophoran cephalic ganglia

    Directory of Open Access Journals (Sweden)

    Z Peña-Contreras

    2007-03-01

    Full Text Available The taxonomic location of the Onychophora has been controversial because of their phenotypic and genotypic characteristics, related to both annelids and arthropods. We analyzed the ultrastructure of the neurons and their synapses in the cephalic ganglion of a poorly known invertebrate, the velvet worm Peripatus sedgwicki, from the mountainous region of El Valle, Mérida, Venezuela. Cephalic ganglia were dissected, fixed and processed for transmission electron microscopy. The animal has a high degree of neurobiological development, as evidenced by the presence of asymmetric (excitatory and symmetric (inhibitory synapses, as well as the existence of glial cell processes in a wide neuropile zone. The postsynaptic terminals were seen to contain subsynaptic cisterns formed by membranes of smooth endoplasmic reticulum beneath the postsynaptic density, whereas the presynaptic terminal showed numerous electron transparent synaptic vesicles. From the neurophylogenetic perspectives, the ultrastructural characteristics of the central nervous tissue of the Onychophora show important evolutionary acquirements, such as the presence of both excitatory and inhibitory synapses, indicating functional synaptic transmission, and the appearance of mature glial cells. Rev. Biol . Trop. 55 (1: 261-267. Epub 2007 March. 31.Estudiamos la ultraestructura de las neuronas y sus sinapsis del ganglio cefálico de un invertebrado poco conocido del phylum Onychophora: Peripatus sedgwicki de los Andes Venezolanos, utilizando para ello la microscopía electrónica de transmisión. La localización taxonómica de los onicóforos ha sido controversial debido a sus características fenotípicas y genotípicas que los relacionan tanto con los anélidos como con los artrópodos. Para este trabajo se estudió el ganglio cefálico de P. sedgwicki de la zona montañosa de El Valle, Mérida, Venezuela. El ganglio cefálico se localiza en la región anterior del animal y fue diseccionado

  11. Cephalic tetanus presenting as acute vertigo with bilateral vestibulopathy.

    Science.gov (United States)

    Kagoya, Ryoji; Iwasaki, Shinichi; Chihara, Yasuhiro; Ushio, Munetaka; Tsuji, Shoji; Murofushi, Toshihisa; Yamasoba, Tatsuya

    2011-03-01

    Cephalic tetanus is a rare form of tetanus, defined by paralysis of more than one cranial nerve. The seventh cranial nerve is the most frequently involved. We report a 58-year-old man with cephalic tetanus and bilateral vestibulopathy. The patient's initial symptoms were rotatory vertigo and hypertension. He then developed trismus and cranial nerve palsies of the fifth and seventh nerves. The caloric test and vestibular evoked mygenic potentials in response to air-conducted clicks revealed absent responses on both sides, although audiometry and auditory brainstem responses were normal in both ears. To the best of our knowledge, this is the first report of involvement of the eighth cranial nerve in cephalic tetanus.

  12. Obstetric and Anesthetic Approaches to External Cephalic Version.

    Science.gov (United States)

    Lim, Stephanie; Lucero, Jennifer

    2017-03-01

    Breech presentation is the most common abnormal fetal presentation and complicates approximately 3% to 4% of all pregnancies. External cephalic version (ECV) should be recommended to women with a breech singleton pregnancy, if there is no maternal or fetal contraindication. ECV increases the chance of cephalic presentation at the onset of labor and decreases the rate of cesarean delivery by almost 40%. The success rate of ECV is approximately 60%. Review of the risks and benefits for performing an ECV and for both the timing of ECV and the number of attempts should be should be discussed with the patient. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. External cephalic version-related risks: a meta-analysis

    NARCIS (Netherlands)

    Grootscholten, K.; Kok, M.; Oei, S.G.; Mol, B.W.J.; Post, van der J.A.

    2008-01-01

    OBJECTIVE: To systematically review the literature on external cephalic version–related complications and to assess if the outcome of a version attempt is related to complications. DATA SOURCES: In March 2007 we searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials.

  14. External Cephalic Version-Related Risks A Meta-analysis

    NARCIS (Netherlands)

    Grootscholten, Kim; Kok, Marjolein; Oei, S. Guid; Mol, Ben W. J.; van der Post, Joris A.

    2008-01-01

    OBJECTIVE: To systematically review the literature on external cephalic version-related complications and to assess if the outcome of a version attempt is related to complications. DATA SOURCES: In March 2007 we searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials.

  15. Prediction of Success of External Cephalic Version after 36 Weeks

    NARCIS (Netherlands)

    Kok, Marjolein; van der Steeg, Jan Willem; van der Post, Joris A. M.; Mol, Ben W. J.

    2011-01-01

    We aimed to develop a predictive model for the chance of a successful external cephalic version (ECV). We performed a prospective cohort study of women with a singleton fetus in breech presentation with a gestational age of 36 weeks or more. Data on parity, maternal age, body mass index, ethnicity,

  16. Radiotherapy of the cephalic segment in patients with advanced neuroblastoma

    International Nuclear Information System (INIS)

    Weltman, Eduardo

    1995-01-01

    Although the treatment results have significantly improved for several pediatric malignant neoplasms, particularly Wilms's tumor, lymphomas and leukemia, in the last decade, the prognosis of the INSS, stage 4 neuroblastoma over one year one old patients remains poor. Even for the more advanced centers, using the more aggressive treatment schedules, such as bone marrow transplantation, the probability of a 2 year progression free interval varies from 6 to 50% and at 3 to 6 years, from 13 to 54%. Thereby, at least, 46 to 94% of these patients are expected to die due to the merciless neoplasm progression. The hypothesis here to be tested is regarding the impact of the cephalic irradiation on the outcome of stage 4 patients with skull metastasis at diagnosis. The end point was to establish, under the NEURO-III-85 protocol chemotherapy schedule, the possible benefit of this radiotherapy in preventing the cephalic recurrence, and its reflex on these patients total and diseases free survival. These results disclosed that the cephalic segment irradiation may prevent recurrences at this site. Unfortunately, the decrease in the cranial recurrence frequency did not affect either the disease free interval, or the total survival. The conclusion was that cephalic irradiation have the potential of avoiding these recurrences, without modifying the final outcome. This modality of radiotherapy must be reevaluated under more effective systemic treatments. (author)

  17. [Cord accident after external cephalic version: Reality or mostly myth?

    Science.gov (United States)

    Boujenah, J; Fleury, C; Pharisien, I; Benbara, A; Tigaizin, A; Bricou, A; Carbillon, L

    2017-01-01

    To study the occurrence of cords accident (nuchal cords, prolapse, and braces) after external cephalic version according to its failure or success. Retrospective study between 1998-2015 comparing in the cord accident diagnosed at delivery (by midwife or doctors according to mode of delivery): Patients with attempt ECV: Group 1 cephalic presentation after successful ECV with trial of labor, and Group 2 failed ECV followed by elective cesarean or trial of labor. Patients with no attempt ECV Group 3 spontaneous cephalic presentation matching for delivery date, maternal age, parity, body mass index, and delivery history with group 1, Group 4 Breech presentation without attempt ECV with trial of labor. A total of 776 women with breech presentation were included (198 in group 1, 446 in group 2, 396 in group 3 and 118 in group 4). The prevalence of cord accident did not differ according to ECV attempt (17.08 % versus 18.9 %), to cephalic presentation (group 1: 24.7 % versus group 3: 25 %) and to breech presentation (group 2: 16.9 % versus group 4: 17.2 %). The trial of labor after failed ECV did not increase the risk of cord accident when compared with elective cesarean (17.4 % versus 16 %). A prolapse cord was only observed after trial of labor, i.e. in groups 1, 2 and 4 without difference (respectively 1, 0.8 and 1.7 %). In each group, the rate of cesarean was not different according to the presence of nuchal cord. Success or failed External cephalic version is not associated with an increased risk of cord accident. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  18. Fear for external cephalic version and depression : Predictors of successful external cephalic version for breech presentation at term?

    NARCIS (Netherlands)

    Ciliacus, Emily; van der Zalm, Marieke; Truijens, Sophie E.; Hasaart, Tom H.; Pop, Victor J.; Kuppens, Simone M.

    2014-01-01

    Background Objective was to determine whether fear for external cephalic version (ECV) and depression are associated with the success rate of ECV in women with a breech presentation at term. Methods Prospective study conducted in the Catharina Hospital Eindhoven between October 2007 and May 2012.

  19. Implementation of the external cephalic version in breech delivery. Dutch national implementation study of external cephalic version

    NARCIS (Netherlands)

    Vlemmix, F.; Rosman, A N; Fleuren, M A H; Rijnders, M E B; Beuckens, A.; Haak, M.C.; Akerboom, B.M.C.; Bais, J.M.J.; Kuppens, S M I; Papatsonis, D.N.M.; Opmeer, Brent C; van der Post, J.A.M.; Mol, B.W.J.; Kok, M

    2010-01-01

    Background: Breech presentation occurs in 3 to 4% of all term pregnancies. External cephalic version (ECV) is proven effective to prevent vaginal breech deliveries and therefore it is recommended by clinical guidelines of the Royal Dutch Organisation for Midwives (KNOV) and the Dutch Society for

  20. Implementation of the external cephalic version in breech delivery Dutch national implementation study of external cephalic version

    NARCIS (Netherlands)

    Vlemmix, Floortje; Rosman, Ageeth N.; Fleuren, Margot A. H.; Rijnders, Marlies E. B.; Beuckens, Antje; Haak, Monique C.; Akerboom, Bettina M. C.; Bais, Joke M. J.; Kuppens, Simone M. I.; Papatsonis, Dimitri N.; Opmeer, Brent C.; van der Post, Joris A. M.; Mol, Ben Willem J.; Kok, Marjolein

    2010-01-01

    ABSTRACT: BACKGROUND: Breech presentation occurs in 3 to 4 % of all term pregnancies. External cephalic version (ECV) is proven effective to prevent vaginal breech deliveries and therefore it is recommended by clinical guidelines of the Royal Dutch Organisation for Midwives (KNOV) and the Dutch

  1. [External cephalic version in cases of breech presentation: renaissance of a well-known procedure?].

    Science.gov (United States)

    Schmidt, M; Callies, R; Kuhn, U; Willruth, A; Kimmig, R

    2009-01-01

    About 3-4% of all pregnant women will have a fetus presenting by the breech at term. External cephalic version offers the opportunity to reduce the rate of caesarean sections caused by breech presentation. We analysed retrospectively 51 cases of external cephalic version at our clinic. External cephalic version was performed 51 times between 37 and 41 weeks of pregnancy. External cephalic version was successful in 32/51 cases (62,7%) with a consecutive rate of vaginal delivery of 71,9%. The best results were seen at 37 weeks of pregnancy with 81,25% of successful versions followed by 76,9% of vaginal deliveries. Complications were rare. There was just 1 case of emergency caesarean section due to persisting fetal bradycardia. External cephalic version is an effective and safe treatment to enable vaginal delivery of cephalic presentation. For this operation, 37 weeks of pregnancy can be considered the best time. 2009 S. Karger AG, Basel.

  2. Classic metaphyseal lesion following external cephalic version and cesarean section

    Energy Technology Data Exchange (ETDEWEB)

    Lysack, John T.; Soboleski, Don [Department of Diagnostic Radiology, Queen' s University, Kingston General Hospital, 76 Stuart Street, K7L 2V7, Kingston, Ont. (Canada)

    2003-06-01

    We report a case of an otherwise healthy neonate diagnosed at birth with a classic metaphyseal lesion of the proximal tibia following external cephalic version for frank breech presentation and a subsequent urgent cesarean section. Although the classic metaphyseal lesion is considered highly specific for infant abuse, this case demonstrates the importance of obtaining a history of obstetric trauma for neonates presenting to the imaging department for suspected non-accidental injury. (orig.)

  3. Classic metaphyseal lesion following external cephalic version and cesarean section

    International Nuclear Information System (INIS)

    Lysack, John T.; Soboleski, Don

    2003-01-01

    We report a case of an otherwise healthy neonate diagnosed at birth with a classic metaphyseal lesion of the proximal tibia following external cephalic version for frank breech presentation and a subsequent urgent cesarean section. Although the classic metaphyseal lesion is considered highly specific for infant abuse, this case demonstrates the importance of obtaining a history of obstetric trauma for neonates presenting to the imaging department for suspected non-accidental injury. (orig.)

  4. Neurogenesis of cephalic sensory organs of Aplysia californica

    DEFF Research Database (Denmark)

    Wollesen, Tim; Wanninger, Andreas; Klussmann-Kolb, Annette

    2007-01-01

    The opisthobranch gastropod Aplysia californica serves as a model organism in experimental neurobiology because of its simple and well-known nervous system. However, its nervous periphery has been less intensely studied. We have reconstructed the ontogeny of the cephalic sensory organs (labial...... tentacles, rhinophores, and lip) of planktonic, metamorphic, and juvenile developmental stages. FMRFamide and serotonergic expression patterns have been examined by immunocytochemistry in conjunction with epifluorescence and confocal laser scanning microscopy. We have also applied scanning electron...

  5. Mode of delivery after successful external cephalic version: a systematic review and meta-analysis.

    Science.gov (United States)

    de Hundt, Marcella; Velzel, Joost; de Groot, Christianne J; Mol, Ben W; Kok, Marjolein

    2014-06-01

    To assess the mode of delivery in women after a successful external cephalic version by performing a systematic review and meta-analysis. We searched MEDLINE, Embase, ClinicalTrials.gov, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library for studies reporting on the mode of delivery in women after successful external cephalic version at term and women with a spontaneous cephalic-presenting fetus. Two reviewers independently selected studies, extracted data, and assessed study quality. The association between mode of delivery and successful external cephalic version was expressed as a common odds ratio with a 95% confidence interval (CI). We identified three cohort studies and eight case-control studies, reporting on 46,641 women. The average cesarean delivery rate for women with a successful external cephalic version was 21%. Women after successful external cephalic version were at increased risk for cesarean delivery for dystocia (odds ratio [OR] 2.2, 95% CI 1.6-3.0), cesarean delivery for fetal distress (OR 2.2, 95% CI 1.6-2.9), and instrumental vaginal delivery (OR 1.4, 95% CI 1.1-1.7). Women who have had a successful external cephalic version for breech presentation are at increased risk for cesarean delivery and instrumental vaginal delivery as compared with women with a spontaneous cephalic presentation. Nevertheless, with a number needed to treat of three, external cephalic version still remains a very efficient procedure to prevent a cesarean delivery.

  6. External cephalic version for breech presentation at term.

    Science.gov (United States)

    Hofmeyr, G Justus; Kulier, Regina; West, Helen M

    2015-04-01

    Management of breech presentation is controversial, particularly in regard to manipulation of the position of the fetus by external cephalic version (ECV). ECV may reduce the number of breech presentations and caesarean sections, but there also have been reports of complications with the procedure. The objective of this review was to assess the effects of ECV at or near term on measures of pregnancy outcome. Methods of facilitating ECV, and ECV before term are reviewed separately. We searched the Cochrane Pregnancy and Childbirth Trials Register (28 February 2015) and reference lists of retrieved studies. Randomised trials of ECV at or near term (with or without tocolysis) compared with no attempt at ECV in women with breech presentation. Two review authors assessed eligibility and trial quality, and extracted the data. We included eight studies, with a total of 1308 women randomised. The pooled data from these studies show a statistically significant and clinically meaningful reduction in non-cephalic presentation at birth (average risk ratio (RR) 0.42, 95% confidence interval (CI) 0.29 to 0.61, eight trials, 1305 women); vaginal cephalic birth not achieved (average RR 0.46, 95% CI 0.33 to 0.62, seven trials, 1253 women, evidence graded very low); and caesarean section (average RR 0.57, 95% CI 0.40 to 0.82, eight trials, 1305 women, evidence graded very low) when ECV was attempted in comparison to no ECV attempted. There were no significant differences in the incidence of Apgar score ratings below seven at one minute (average RR 0.67, 95% CI 0.32 to 1.37, three trials, 168 infants) or five minutes (RR 0.63, 95% CI 0.29 to 1.36, five trials, 428 infants, evidence graded very low), low umbilical vein pH levels (RR 0.65, 95% CI 0.17 to 2.44, one trial, 52 infants, evidence graded very low), neonatal admission (RR 0.80, 95% CI 0.48 to 1.34, four trials, 368 infants, evidence graded very low), perinatal death (RR 0.39, 95% CI 0.09 to 1.64, eight trials, 1305 infants

  7. Nifedipine as a uterine relaxant for external cephalic version: a randomized controlled trial.

    Science.gov (United States)

    Kok, Marjolein; Bais, Joke M; van Lith, Jan M; Papatsonis, Dimitri M; Kleiverda, Gunilla; Hanny, Dahrs; Doornbos, Johannes P; Mol, Ben W; van der Post, Joris A

    2008-08-01

    To estimate the effectiveness of nifedipine as a uterine relaxant during external cephalic version to correct breech presentation. In this randomized, double-blind, placebo-controlled trial, women with a singleton fetus in breech presentation and a gestational age of 36 weeks or more were eligible for enrollment. Participating women received two doses of either nifedipine 10 mg or placebo, 30 and 15 minutes before the external cephalic version attempt. The primary outcome was a cephalic-presenting fetus immediately after the procedure. Secondary outcome measures were cephalic presentation at delivery, mode of delivery, and adverse events. A sample size of 292 was calculated to provide 80% power to detect a 17% improvement of the external cephalic version success rate, assuming a placebo group rate of 40% and alpha of .05. Outcome data for 310 of 320 randomly assigned participants revealed no significant difference in external cephalic version success rates between treatment (42%) and control group (37%) (relative risk 1.1, 95%; 95% confidence interval 0.85-1.5). The cesarean delivery rate was 51% in the treatment group and 46% in the control group (relative risk 1.1, 95% confidence interval 0.88-1.4). Nifedipine did not significantly improve the success of external cephalic version. Future use of nifedipine to improve the outcome of external cephalic version should be limited to large clinical trials.

  8. Prevalence, Outcome, and Women's Experiences of External Cephalic Version in a Low-Risk Population

    NARCIS (Netherlands)

    Rijnders, Marlies; Offerhaus, Pien; van Dommelen, Paula; Wiegers, Therese; Buitendijk, Simone

    2010-01-01

    Background: Until recently, external cephalic version to prevent breech presentation at birth was not widely accepted. The objective of our study was to assess the prevalence, outcomes, and women's experiences of external cephalic version to improve the implementation of the procedure in the

  9. Prevalence, outcome, and women's experiences of external cephalic version in a low-risk population

    NARCIS (Netherlands)

    Rijnders, M.; Offerhaus, P.; Dommelen, P. van; Wiegers, T.; Buitendijk, S.

    2010-01-01

    Background: Until recently, external cephalic version to prevent breech presentation at birth was not widely accepted. The objective of our study was to assess the prevalence, outcomes, and women's experiences of external cephalic version to improve the implementation of the procedure in the

  10. Timing of delivery after external cephalic version and the risk for cesarean delivery.

    Science.gov (United States)

    Kabiri, Doron; Elram, Tamar; Aboo-Dia, Mushira; Elami-Suzin, Matan; Elchalal, Uriel; Ezra, Yossef

    2011-08-01

    To estimate the association between time of delivery after external cephalic version at term and the risk for cesarean delivery. This retrospective cohort study included all successful external cephalic versions performed in a tertiary center between January 1997 and January 2010. Stepwise logistic regression was used to calculate the odds ratio (OR) for cesarean delivery. We included 483 external cephalic versions in this study, representing 53.1% of all external cephalic version attempts. The incidence of cesarean delivery for 139 women (29%) who gave birth less than 96 hours from external cephalic version was 16.5%; for 344 women (71%) who gave birth greater than 96 hours from external cephalic version, the incidence of cesarean delivery was 7.8% (P = .004). The adjusted OR for cesarean delivery was 2.541 (95% confidence interval 1.36-4.72). When stratified by parity, the risk for cesarean delivery when delivery occurred less than 96 hours after external cephalic version was 2.97 and 2.28 for nulliparous and multiparous women, respectively. Delivery at less than 96 hours after successful external cephalic version was associated with an increased risk for cesarean delivery. III.

  11. Cephalic version by postural management for breech presentation.

    Science.gov (United States)

    Hofmeyr, G Justus; Kulier, Regina

    2012-10-17

    Babies with breech presentation (bottom first) are at increased risk of complications during birth, and are often delivered by caesarean section. The chance of breech presentation persisting at the time of delivery, and the risk of caesarean section, can be reduced by external cephalic version (ECV - turning the baby by manual manipulation through the mother's abdomen). It is also possible that maternal posture may influence fetal position. Many postural techniques have been used to promote cephalic version. The objective of this review was to assess the effects of postural management of breech presentation on measures of pregnancy outcome. We evaluated procedures in which the mother rests with her pelvis elevated. These include the knee-chest position, and a supine position with the pelvis elevated with a wedge-shaped cushion. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (22 August 2012). Randomised and quasi-randomised trials comparing postural management with pelvic elevation for breech presentation, with a control group. One or both review authors assessed eligibility and trial quality. We have included six studies involving a total of 417 women. The rates for non-cephalic births, Cesarean section and Apgar scores below 7 at one minute, regardless of whether ECV was attempted or not, were similar between the intervention and control groups (risk ratio (RR) 0.98; 95% confidence interval (CI) 0.84 to 1.15; RR 1.10; 95% CI 0.89 to 1.37; RR 0.88; 95% CI 0.50 to 1.55). There is insufficient evidence from well-controlled trials to support the use of postural management for breech presentation. The numbers of women studied to date remain relatively small. Further research is needed.

  12. Practice Bulletin No. 161 Summary: External Cephalic Version.

    Science.gov (United States)

    2016-02-01

    In the United States, there is a widespread belief that the overall cesarean delivery rate is higher than necessary. Efforts are being directed toward decreasing the number of these procedures, in part by encouraging physicians to make changes in their management practices. Because breech presentations are associated with a high rate of cesarean delivery, there is renewed interest in techniques such as external cephalic version (ECV) and vaginal breech delivery. The purpose of this document is to provide information about ECV by summarizing the relevant evidence presented in published studies and to make recommendations regarding its use in obstetric practice.

  13. Prediction of Success in External Cephalic Version under Tocolysis: Still a Challenge.

    Science.gov (United States)

    Vaz de Macedo, Carolina; Clode, Nuno; Mendes da Graça, Luís

    2015-01-01

    External cephalic version is a procedure of fetal rotation to a cephalic presentation through manoeuvres applied to the maternal abdomen. There are several prognostic factors described in literature for external cephalic version success and prediction scores have been proposed, but their true implication in clinical practice is controversial. We aim to identify possible factors that could contribute to the success of an external cephalic version attempt in our population. We retrospectively examined 207 consecutive external cephalic version attempts under tocolysis conducted between January 1997 and July 2012. We consulted the department's database for the following variables: race, age, parity, maternal body mass index, gestational age, estimated fetal weight, breech category, placental location and amniotic fluid index. We performed descriptive and analytical statistics for each variable and binary logistic regression. External cephalic version was successful in 46.9% of cases (97/207). None of the included variables was associated with the outcome of external cephalic version attempts after adjustment for confounding factors. We present a success rate similar to what has been previously described in literature. However, in contrast to previous authors, we could not associate any of the analysed variables with success of the external cephalic version attempt. We believe this discrepancy is partly related to the type of statistical analysis performed. Even though there are numerous prognostic factors identified for the success in external cephalic version, care must be taken when counselling and selecting patients for this procedure. The data obtained suggests that external cephalic version should continue being offered to all eligible patients regardless of prognostic factors for success.

  14. Comparison of Fetomaternal Outcome between 47 Deliveries Following Successful External Cephalic Version for Breech Presentation and 7456 Deliveries Following Spontaneous Cephalic Presentation.

    Science.gov (United States)

    de Gregorio, Nikolaus; Friedl, Thomas; Schramm, Amelie; Reister, Frank; Janni, Wolfgang; Ebner, Florian

    2017-08-25

    Achieving a cephalic position after a successful external cephalic version (ECV) is desired to result in delivery and fetal outcomes that are similar to those of deliveries following spontaneous cephalic presentation. We performed a retrospective cohort study including patients with successful ECV following fetal breech position (ECV cohort, n = 47) or with a singleton spontaneous cephalic pregnancy at ≥37 weeks of gestational age (control group, n = 7,456) attempting a vaginal delivery between 2010 and 2013 at the University Hospital Ulm. The mode of delivery and fetal outcome parameters were compared between these 2 groups using nonparametric statistics. ECV cohort and control group did not differ with respect to maternal age, parity, gestational age at birth, and fetal gender. There were no significant differences between the 2 groups with regard to all parameters indicating fetal outcome. However, the rate of cesarean sections was higher after successful ECV compared to spontaneous cephalic presentation (27.7 vs. 12.8%, OR 2.615). While vaginal delivery is less likely to happen after a successful ECV compared to spontaneous cephalic singleton pregnancies, fetal outcome parameters showed no difference between the 2 groups. Physicians should be counseling and encouraging women to attempt ECV, as it is a safe and effective procedure. © 2017 S. Karger AG, Basel.

  15. Implementation of the external cephalic version in breech delivery. Dutch national implementation study of external cephalic version.

    Science.gov (United States)

    Vlemmix, Floortje; Rosman, Ageeth N; Fleuren, Margot A H; Rijnders, Marlies E B; Beuckens, Antje; Haak, Monique C; Akerboom, Bettina M C; Bais, Joke M J; Kuppens, Simone M I; Papatsonis, Dimitri N; Opmeer, Brent C; van der Post, Joris A M; Mol, Ben Willem J; Kok, Marjolein

    2010-05-10

    Breech presentation occurs in 3 to 4% of all term pregnancies. External cephalic version (ECV) is proven effective to prevent vaginal breech deliveries and therefore it is recommended by clinical guidelines of the Royal Dutch Organisation for Midwives (KNOV) and the Dutch Society for Obstetrics and Gynaecology (NVOG). Implementation of ECV does not exceed 50 to 60% and probably less.We aim to improve the implementation of ECV to decrease maternal and neonatal morbidity and mortality due to breech presentations. This will be done by defining barriers and facilitators of implementation of ECV in the Netherlands. An innovative implementation strategy will be developed based on improved patient counselling and thorough instructions of health care providers for counselling. The ultimate purpose of this implementation study is to improve counselling of pregnant women and information of clinicians to realize a better implementation of ECV.The first phase of the project is to detect the barriers and facilitators of ECV. The next step is to develop an implementation strategy to inform and counsel pregnant women with a breech presentation, and to inform and educate care providers. In the third phase, the effectiveness of the developed implementation strategy will be evaluated in a randomised trial. The study population is a random selection of midwives and gynaecologists from 60 to 100 hospitals and practices. Primary endpoints are number of counselled women. Secondary endpoints are process indicators, the amount of fetes in cephalic presentation at birth, complications due to ECV, the number of caesarean sections and perinatal condition of mother and child. Cost effectiveness of the implementation strategy will be measured. This study will provide evidence for the cost effectiveness of a structural implementation of external cephalic versions to reduce the number of breech presentations at term. Dutch Trial Register (NTR): 1878.

  16. Implementation of the external cephalic version in breech delivery. Dutch national implementation study of external cephalic version

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    Papatsonis Dimitri N

    2010-05-01

    Full Text Available Abstract Background Breech presentation occurs in 3 to 4% of all term pregnancies. External cephalic version (ECV is proven effective to prevent vaginal breech deliveries and therefore it is recommended by clinical guidelines of the Royal Dutch Organisation for Midwives (KNOV and the Dutch Society for Obstetrics and Gynaecology (NVOG. Implementation of ECV does not exceed 50 to 60% and probably less. We aim to improve the implementation of ECV to decrease maternal and neonatal morbidity and mortality due to breech presentations. This will be done by defining barriers and facilitators of implementation of ECV in the Netherlands. An innovative implementation strategy will be developed based on improved patient counselling and thorough instructions of health care providers for counselling. Method/design The ultimate purpose of this implementation study is to improve counselling of pregnant women and information of clinicians to realize a better implementation of ECV. The first phase of the project is to detect the barriers and facilitators of ECV. The next step is to develop an implementation strategy to inform and counsel pregnant women with a breech presentation, and to inform and educate care providers. In the third phase, the effectiveness of the developed implementation strategy will be evaluated in a randomised trial. The study population is a random selection of midwives and gynaecologists from 60 to 100 hospitals and practices. Primary endpoints are number of counselled women. Secondary endpoints are process indicators, the amount of fetes in cephalic presentation at birth, complications due to ECV, the number of caesarean sections and perinatal condition of mother and child. Cost effectiveness of the implementation strategy will be measured. Discussion This study will provide evidence for the cost effectiveness of a structural implementation of external cephalic versions to reduce the number of breech presentations at term. Trial

  17. Route of delivery following successful external cephalic version.

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    Policiano, Catarina; Costa, Ana; Valentim-Lourenço, Alexandre; Clode, Nuno; Graça, Luís M

    2014-09-01

    To evaluate the delivery route and the indications for cesarean delivery after successful external cephalic version (ECV). A retrospective matched case-control study was conducted at a hospital in Lisbon, Portugal, between 2002 and 2012. Each woman who underwent successful ECV (n = 44) was compared with the previous and next women who presented for labor management and who had the same parity and a singleton vertex pregnancy at term (n = 88). The outcome measures were route of delivery, indications for cesarean delivery, and incidence of nonreassuring fetal status. Attempts at ECV were successful in 62 (46%) of 134 women, and 44 women whose fetuses remained in a cephalic presentation until delivery were included in the study. The rates of intrapartum cesarean delivery and operative vaginal delivery did not differ significantly between cases and controls (intrapartum cesarean delivery, 9 [20%] vs 16 [18%], P = 0.75; operative vaginal delivery, 14 [32%] vs 19 [22%], P = 0.20). The indications for cesarean delivery after successful ECV did not differ; in both groups, cesarean delivery was mainly performed for labor arrest disorders (cases, 6 [67%] vs controls, 13 [81%]; P = 0.63). Successful ECV was not associated with increased rates of intrapartum cesarean delivery or operative vaginal delivery. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  18. The CT evaluation of cephalic and cervical adenoid cystic carcinoma

    International Nuclear Information System (INIS)

    Gu Yajia; Wang Jiuhua; Wang HOngshi; Chen Tongzhen

    2000-01-01

    Objective: To evaluate the CT manifestations of cephalic and cervical adenoid cystic carcinoma (ACC). Methods: Thirty-three cases of ACC were analyzed retrospectively. Of all cases, 22 cases underwent operation and 11 cases received radiotherapy. The manifestations of CT were evaluated and compared with the clinical and pathologic results. Results: Tumors originated from parotid gland (5 cases), floor of mouth (5 cases), nasal cavity and nasopharynx (5 cases), tongue (4 cases), palate (3 cases), tracheas (3 cases), submandibular gland (2 cases), tonsilla (2 cases), maxillary sinus (2 cases), and cheek (2 cases), respectively. The CT manifestations included: (1)ethmoid density in 21 cases, partial ethmoid density in 5 cases. (2)the morphology of ACC was irregular and the growth of the tumor was amorphous in 17 cases, and the margin of the tumor was vague in 20 cases. (3)ACC often grew along the nerve with infiltration, which caused destruction of the skull base in 5 cases and atrophy of mastication muscles and/or buccinator in 3 cases. Conclusion: (1)The characteristics of cephalic and cervical adenoid cystic carcinoma on CT scans were ethmoid density, infiltrated growth, growing along the nerve with infiltration, and submucous growth. Among them, the most important manifestation, which could lead to the histologic diagnosis on CT, was ethmoid density. (2)The range of ACC was usually underestimated on CT. (3)The manifestation of tumor growth along the nerve could be apparently displayed on MRI

  19. Predictors of Cephalic Vaginal Delivery Following External Cephalic Version: An Eight-Year Single-Centre Study of 447 Cases

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    Natalie Kew

    2017-01-01

    Full Text Available Introduction. Our study aims to investigate and evaluate (1 rates of success of ECV for breech presentation at term at the Royal Women’s Hospital in comparison to international standards; (2 mode of delivery following ECV; (3 factors influencing success rates of ECV at the Royal Women’s Hospital. Methods. An audit of all women who underwent ECV between the years 2007 and 2014 at the Royal Women’s Hospital as public patients was completed. Data parameters were collected from paper and electronic patient files at the Women’s Hospital. Data was collected to analyse the effect of the following parameters on ECV success and birth outcome: age, parity, gestational age, BMI, AFI, and tocolytic use. These parameters were analysed to determine their effect on ECV outcome and birth outcome. Results. The Women’s Hospital, Melbourne, has an ECV success rate of approximately 37%. Of the patients undergoing ECV, 29% proceeded to normal vaginal delivery. Predictors of successful ECV included low BMI, multiparity, and AFI more than 16 (P<0.05. The only predictor of cephalic vaginal delivery following ECV was multiparity. Negative predictors of cephalic delivery were low AFI and nulliparity. Conclusions. The success rate of ECV at the Women’s Hospital, Melbourne, is in line with global standards.

  20. Women's experiences of participating in the early external cephalic version 2 trial.

    Science.gov (United States)

    Murray-Davis, Beth; Marion, Anya; Malott, Anne; Reitsma, Angela; Hutton, Eileen K

    2012-03-01

    The international, multicenter External Cephalic Version 2 (ECV2) Trial compared early external cephalic version at 34(0/7) to 35(6/7) weeks with that at greater than 37 weeks. A total of 1,543 women were randomized from 68 centers in 21 countries. The goal of this component of the trial was to understand women's views about participation in a research trial and timing of external cephalic version. A postpartum questionnaire was completed containing a 5-point Likert scale examining contact and availability of staff, choice of timing of external cephalic version, preference of randomization, convenience of participating, and overall satisfaction. Participants also completed two open-ended questions related to timing of external cephalic version and satisfaction with the trial. Descriptive statistics and content analysis were used to analyze data. A total of 1,458 women completed the questionnaire, of whom 86 percent said "yes"-they would participate in the trial again. Themes influencing decisions about participating were perceptions of the external cephalic version experience, preferred mode of delivery, preferred timing of external cephalic version, and perceptions of the effectiveness of external cephalic version and of the trial environment. Many participants preferred the early timing of the procedure offered through the trial because of perceived advantages of a smaller baby being easier to turn and the opportunity for repeat procedures. Women were positive about their participation in the trial. Early external cephalic version was preferred over the traditional timing as it was perceived to afford both physiologic and practical advantages. © 2012, Copyright the Authors. Journal compilation © 2012, Wiley Periodicals, Inc.

  1. Predictors of successful outcomes after external cephalic version in singleton term breech pregnancies: a nine-year historical cohort study.

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    Cho, L Y; Lau, W L; Lo, T K; Tang, Helen H T; Leung, W C

    2012-02-01

    To study the success rate, predictors for success, and pregnancy outcomes after external cephalic version. Historical cohort study. Regional hospital, Hong Kong. All women who had singleton term breech pregnancies at term and opted for external cephalic version during 2001 and 2009. Their demographic data, clinical and ultrasound findings, procedure details, complications, and delivery outcomes were analysed. Predictive factors for successful external cephalic version. A total of 209 external cephalic versions were performed during the 9-year period. The success rate was 63% (75% for multiparous and 53% for nulliparous women). There was no significant complication. On univariate analysis, predictors of successful external cephalic version were: multiparity, unengaged presenting part, higher amniotic fluid index (≥ 10 cm), thin abdominal wall, low uterine tone, and easily palpable fetal head (subjective assessment by practitioners before external cephalic version). On multivariate analysis, only multiparity, non-engagement of the fetal buttock and thin maternal abdomen were associated with successful external cephalic version. In all, 69% of those who had successful external cephalic version succeeded in the first roll (Pexternal cephalic versions had vaginal deliveries (93% in multiparous and 69% in nulliparous women). Uptake rate of external cephalic version was studied in the latter part of the study period (2006-2009). Whilst 735 women were eligible for external cephalic version, 131 women chose to have the procedure resulting in an uptake rate of 18%. External cephalic version was effective in reducing breech presentations at term and corresponding caesarean section rates, but the uptake rate was low. Further work should address the barriers to the low acceptance of external cephalic version. The results of this study could encourage women to opt for external cephalic version.

  2. External cephalic version for breech presentation before term.

    Science.gov (United States)

    Hutton, Eileen K; Hofmeyr, G Justus; Dowswell, Therese

    2015-07-29

    External cephalic version (ECV) of the breech fetus at term (after 37 weeks) has been shown to be effective in reducing the number of breech presentations and caesarean sections, but the rates of success are relatively low. This review examines studies initiating ECV prior to term (before 37 weeks' gestation). To assess the effectiveness of a policy of beginning ECV before term (before 37 weeks' gestation) for breech presentation on fetal presentation at birth, method of delivery, and the rate of preterm birth, perinatal morbidity, stillbirth or neonatal mortality. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2015) and reference lists of retrieved studies. Randomised controlled trials (RCTs) of ECV attempted before term (37 weeks' gestation) or commenced before term, compared with a control group of women (in breech presentation) in which either no ECV attempted or ECV was attempted at term. Cluster-randomised trials were eligible for inclusion but none were identified. Quasi-RCTs or studies using a cross-over design were not eligible for inclusion. Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked for accuracy. Studies were assessed for risk of bias and for important outcomes the overall quality of the evidence was assessed using the GRADE approach. Five studies are included (2187 women). It was not possible for the intervention to be blinded, and it is not clear what impact lack of blinding would have on the outcomes reported. For other 'Risk of bias' domains studies were either at low or unclear risk of bias.One study reported on ECV that was undertaken and completed before 37 weeks' gestation compared with no ECV. No difference was found in the rate of non-cephalic presentation at birth (risk ratio (RR) 1.04, 95% confidence interval (CI) 0.64 to 1.69; participants = 102). One study reported on a policy of ECV that was initiated before term (33 weeks) and up until 40

  3. Successful External Cephalic Version: Factors Predicting Vaginal Birth

    Science.gov (United States)

    Lim, Pei Shan; Ng, Beng Kwang; Ali, Anizah; Shafiee, Mohamad Nasir; Kampan, Nirmala Chandralega; Mohamed Ismail, Nor Azlin; Omar, Mohd Hashim; Abdullah Mahdy, Zaleha

    2014-01-01

    Purpose. To determine the maternal and fetal outcomes of successful external cephalic version (ECV) as well as factors predicting vaginal birth. Methods. The ECV data over a period of three years at Universiti Kebangsaan Malaysia Medical Centre (UKMMC) between 1 September 2008 and 30 September 2010 was reviewed. Sixty-seven patients who had successful ECV were studied and reviewed for maternal, fetal, and labour outcomes. The control group comprised patients with cephalic singletons of matching parity who delivered following the index cases. Results. The mean gestational age at ECV was 263 ± 6.52 days (37.5 weeks ± 6.52 days). Spontaneous labour and transient cardiotocographic (CTG) changes were the commonest early adverse effects following ECV. The reversion rate was 7.46%. The mean gestational age at delivery of the two groups was significantly different (P = 0.000) with 277.9 ± 8.91 days and 269.9 ± 9.68 days in the study group and control groups, respectively. The study group needed significantly more inductions of labour. They required more operative deliveries, had more blood loss at delivery, a higher incidence of meconium-stained liquor, and more cord around the neck. Previous flexed breeches had a threefold increase in caesarean section rate compared to previous extended breeches (44.1% versus 15.2%, P = 0.010). On the contrary, an amniotic fluid index (AFI) of 13 or more is significantly associated with a higher rate of vaginal birth (86.8% versus 48.3%, P = 0.001). Conclusions. Patients with successful ECV were at higher risk of carrying the pregnancy beyond 40 weeks and needing induction of labour, with a higher rate of caesarean section and higher rates of obstetrics complications. Extended breech and AFI 13 or more were significantly more likely to deliver vaginally postsuccessful ECV. This additional information may be useful to caution a patient with breech that ECV does not bring them to behave exactly like a normal cephalic, so that they

  4. Successful External Cephalic Version: Factors Predicting Vaginal Birth

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    Pei Shan Lim

    2014-01-01

    Full Text Available Purpose. To determine the maternal and fetal outcomes of successful external cephalic version (ECV as well as factors predicting vaginal birth. Methods. The ECV data over a period of three years at Universiti Kebangsaan Malaysia Medical Centre (UKMMC between 1 September 2008 and 30 September 2010 was reviewed. Sixty-seven patients who had successful ECV were studied and reviewed for maternal, fetal, and labour outcomes. The control group comprised patients with cephalic singletons of matching parity who delivered following the index cases. Results. The mean gestational age at ECV was 263±6.52 days (37.5 weeks ± 6.52 days. Spontaneous labour and transient cardiotocographic (CTG changes were the commonest early adverse effects following ECV. The reversion rate was 7.46%. The mean gestational age at delivery of the two groups was significantly different (P=0.000 with 277.9±8.91 days and 269.9±9.68 days in the study group and control groups, respectively. The study group needed significantly more inductions of labour. They required more operative deliveries, had more blood loss at delivery, a higher incidence of meconium-stained liquor, and more cord around the neck. Previous flexed breeches had a threefold increase in caesarean section rate compared to previous extended breeches (44.1% versus 15.2%, P=0.010. On the contrary, an amniotic fluid index (AFI of 13 or more is significantly associated with a higher rate of vaginal birth (86.8% versus 48.3%, P=0.001. Conclusions. Patients with successful ECV were at higher risk of carrying the pregnancy beyond 40 weeks and needing induction of labour, with a higher rate of caesarean section and higher rates of obstetrics complications. Extended breech and AFI 13 or more were significantly more likely to deliver vaginally postsuccessful ECV. This additional information may be useful to caution a patient with breech that ECV does not bring them to behave exactly like a normal cephalic, so that they

  5. Moxibustion for cephalic version: a feasibility randomised controlled trial

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    Bisits Andrew

    2011-09-01

    Full Text Available Abstract Background Moxibustion (a type of Chinese medicine which involves burning a herb close to the skin has been used to correct a breech presentation. Evidence of effectiveness and safety from systematic reviews is encouraging although significant heterogeneity has been found among trials. We assessed the feasibility of conducting a randomised controlled trial of moxibustion plus usual care compared with usual care to promote cephalic version in women with a breech presentation, and examined the views of women and health care providers towards implementing a trial within an Australian context. Methods The study was undertaken at a public hospital in Newcastle, New South Wales, Australia. Women at 34-36.5 weeks of gestation with a singleton breech presentation (confirmed by ultrasound, were randomised to moxibustion plus usual care or usual care alone. The intervention was administered over 10 days. Clinical outcomes included cephalic presentation at birth, the need for ECV, mode of birth; perinatal morbidity and mortality, and maternal complications. Feasibility outcomes included: recruitment rate, acceptability, compliance and a sample size for a future study. Interviews were conducted with 19 midwives and obstetricians to examine the acceptability of moxibustion, and views on the trial. Results Twenty women were randomised to the trial. Fifty one percent of women approached accepted randomisation to the trial. A trend towards an increase in cephalic version at delivery (RR 5.0; 95% CI 0.7-35.5 was found for women receiving moxibustion compared with usual care. There was also a trend towards greater success with version following ECV. Two babies were admitted to the neonatal unit from the moxibustion group. Compliance with the moxibustion protocol was acceptable with no reported side effects. Clinicians expressed the need for research to establish the safety and efficacy of moxibustion, and support for the intervention was given to

  6. Probability of cesarean delivery after successful external cephalic version.

    Science.gov (United States)

    Burgos, Jorge; Iglesias, María; Pijoan, José I; Rodriguez, Leire; Fernández-Llebrez, Luis; Martínez-Astorquiza, Txantón

    2015-11-01

    To identify factors associated with cesarean delivery following successful external cephalic version (ECV). In a prospective study, data were obtained for ECV procedures performed at Cruces University Hospital, Spain, between March 2002 and June 2012. Women with a singleton pregnancy who had a successful, uncomplicated ECV and whose delivery was assisted at the study hospital, with the fetus in cephalic presentation, were included. A multivariate model of risk factors of cesarean delivery was developed. Among 627 women included, 92 (14.7%) delivered by cesarean. A cesarean was performed among 33 (8.5%) of 387 women with spontaneous labor versus 59 (24.6%) of 240 who were induced (P < 0.001). Multivariate analysis showed that higher BMI (P = 0.006), labor induction (P = 0.001), and prior cesarean (P < 0.001) were associated with cesarean. Time between ECV and delivery was inversely associated with probability of cesarean during the first 2 weeks. Thus, the probabilities of cesarean delivery on the first day were 0.53 (95% CI 0.35-0.71) and 0.34 (95% CI 0.18-0.51) following induced and spontaneous labor, respectively. On the seventh day, the probabilities were 0.23 (95% CI 0.15-0.32) and 0.12 (95% CI 0.07-0.18), respectively. Following ECV, induction of labor, an interval of less than 2 weeks to delivery, BMI, and previous cesarean were associated with an increased risk of cesarean. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  7. Interventions to help external cephalic version for breech presentation at term.

    Science.gov (United States)

    Hofmeyr, G J

    2004-01-01

    Breech presentation places a fetus at increased risk. The outcome for the baby is improved by planned caesarean section compared with planned vaginal delivery. External cephalic version attempts to reduce the chances of breech presentation at birth, but is not always successful. Tocolytic drugs to relax the uterus as well as other methods have been used in an attempt to facilitate external cephalic version at term. To assess the effects of routine tocolysis, fetal acoustic stimulation, epidural or spinal analgesia and transabdominal amnioinfusion for external cephalic version at term on successful version and measures of pregnancy outcome. The Cochrane Pregnancy and Childbirth Group trials register (September 2003) and the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 3, 2003) were searched. Randomised and quasi-randomised trials comparing routine versus selective or no tocolysis; fetal acoustic stimulation in midline fetal spine positions versus dummy or no stimulation; epidural or spinal analgesia versus no regional analgesia; or transabdominal amnioinfusion versus no amnioinfusion for external cephalic version at term. The reviewer assessed eligibility and trial quality. In six trials, routine tocolysis with beta-stimulants was associated with fewer failures of external cephalic version (relative risk (RR) 0.74, 95% confidence interval (CI) 0.64 to 0.87). The reduction in non-cephalic presentations at birth was not statistically significant. Caesarean sections were reduced (RR 0.85, 95% CI 0.72 to 0.99). In four small trials, sublingual nitroglycerine used as a tocolytic was associated with significant side-effects, and was not found to be effective. Fetal acoustic stimulation in midline fetal spine positions was associated with fewer failures of external cephalic version at term (RR 0.17, 95% CI 0.05 to 0.60). With epidural or spinal analgesia, external cephalic version failure, non-cephalic births and caesarean sections were

  8. [External cephalic version of breech fetus after 36 weeks of gestation - evaluation of efectiveness and complications].

    Science.gov (United States)

    Hruban, L; Janků, P; Jordánová, K; Gerychová, R; Huser, M; Ventruba, P; Roztočil, A

    2017-01-01

    Evaluation of success rate and the safety of external cephalic version after 36 weeks of gestation. Retrospective analysis. Department of Obstetrics and Gynecology, Masaryk University, University Hospital Brno. A retrospective analysis of external cephalic version attempts performed on a group of 638 singleton breech pregnancies after 36 weeks gestation in the years 2003-2016 at the Department of Gynecology and Obstetrics, Masaryk University, Brno. The effectiveness, number and type of complications, mode of delivery and perinatal result were observed. The effectiveness of external cephalic version from breech to head presentation was 47.8% (305 cases). After a successful external cephalic version 238 patients (78.0%) gave birth vaginally. After unsuccessful cephalic version 130 patients (39.0%) gave birth vaginally. The number of serious complications did not exceed 0,9% and did not affect perinatal outcomes. External cephalic version-related emergency cesarean deliveries occurred in 6 cases (2 placental abruption, 4 abnormal cardiotocography). The fetal outcome was good in all these cases. The death of the fetus in connection with the external version has not occurred in our file. Spontaneous discharge of amniotic fluid within 24 hours after procedure occurred in 5 cases (0.8%). The spontaneous onset of labor within 24 hours of procedure occurred in 5 cases (0.8%). The pH value of a. umbilicalis external version and in the group with unsuccessful external version in 9 cases. The Apgar score in the 5th minute external cephalic version of the fetus in the case of breech presentation after the 36th week of pregnancy is an effective and safe alternative for women who have a fear of the vaginal breech delivery. Performing the external cephalic version can reduce the rate of elective caesarean sections due to breech presentation at term.

  9. Remifentanil versus placebo for analgesia during external cephalic version: a randomised clinical trial.

    Science.gov (United States)

    Muñoz, H; Guerra, S; Perez-Vaquero, P; Valero Martinez, C; Aizpuru, F; Lopez-Picado, A

    2014-02-01

    Breech presentation occurs in up to 3% of pregnancies at term and may be an indication for caesarean delivery. External cephalic version can be effective in repositioning the fetus in a cephalic presentation, but may be painful for the mother. Our aim was to assess the efficacy of remifentanil versus placebo for pain relief during external cephalic version. A randomized, double-blind, controlled trial that included women at 36-41 weeks of gestation with non-cephalic presentations was performed. Women were randomized to receive either a remifentanil infusion at 0.1 μg/kg/min and demand boluses of 0.1 μg/kg, or saline placebo. The primary outcome was the numerical rating pain score (0-10) after external cephalic version. Sixty women were recruited, 29 in the control group and 31 in the remifentanil group. There were significant differences in pain scores at the end of the procedure (control 6.5 ± 2.4 vs. remifentanil 4.7 ± 2.5, P = 0.005) but not 10 min later (P = 0.054). The overall success rate for external cephalic version was 49% with no significant differences between groups (remifentanil group 54.8% vs. control group 41.3%, P = 0.358). In the remifentanil group, there was one case of nausea and vomiting, one of drowsiness and three cases of fetal bradycardia. In the control group, there were three cases of nausea and vomiting, one of dizziness and nine cases of fetal bradycardia. Intravenous remifentanil with bolus doses on demand during external cephalic version achieved a reduction in pain and increased maternal satisfaction. There were no additional adverse effects, and no difference in the success rate of external cephalic version or the incidence of fetal bradycardia. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Risk of developmental dysplasia of the hip in breech presentation: the effect of successful external cephalic version.

    Science.gov (United States)

    Lambeek, A F; De Hundt, M; Vlemmix, F; Akerboom, B M C; Bais, J M J; Papatsonis, D N M; Mol, B W J; Kok, M

    2013-04-01

    To evaluate the effect of successful external cephalic version on the incidence of developmental dysplasia of the hip (DDH) requiring treatment in singleton breech presentation at term. Observational cohort study. Three large teaching hospitals in the Netherlands. Women with a singleton breech presentation of 34 weeks of gestation or more, who underwent an external cephalic version attempt. We made a comparison of the incidence of DDH between children born in breech presentation and children born in cephalic presentation after a successful external cephalic version. The incidence of DDH requiring either conservative treatment, with a harness, or surgical treatment. A total of 498 newborns were included in the study, of which 40 (8%) were diagnosed with DDH and 35 required treatment. Multivariate analysis showed that female gender (OR 2.79, 95% CI 1.23-6.35) and successful external cephalic version (OR 0.29, 95% CI 0.09-0.95) were independently associated with DDH. A successful external cephalic version is associated with a lower incidence of DDH, although a high percentage of children born after a successful external cephalic version still appear to have DDH. A larger cohort study is needed to establish the definite nature of this relationship. Until then, we recommend the same screening policy for infants born in cephalic position after a successful external cephalic version as for infants born in breech position. © 2012 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2012 RCOG.

  11. Mode of childbirth and neonatal outcome after external cephalic version: A prospective cohort study.

    Science.gov (United States)

    Rosman, A N; Vlemmix, F; Ensing, S; Opmeer, B C; Te Hoven, S; Velzel, J; de Hundt, M; van den Berg, S; Rota, H; van der Post, J A M; Mol, B W J; Kok, M

    2016-08-01

    to assess the mode of childbirth and adverse neonatal outcomes in women with a breech presentation with or without an external cephalic version attempt, and to compare the mode of childbirth among women with successful ECV to women with a spontaneous cephalic presentation. prospective matched cohort study. 25 clusters (hospitals and its referring midwifery practices) in the Netherlands. Data of the Netherlands perinatal registry for the matched cohort. singleton pregnancies from January 2011 to August 2012 with a fetus in breech presentation and a childbirth from 36 weeks gestation onwards. Spontaneous cephalic presentations (selected from national registry 2009 and 2010) were matched in a 2:1 ratio to cephalic presentations after a successful version attempt. Matching criteria were maternal age, parity, gestational age at childbirth and fetal gender. Main outcomes were mode of childbirth and neonatal outcomes. of 1613 women eligible for external cephalic version, 1169 (72.5%) received an ECV attempt. The overall caesarean childbirth rate was significantly lower compared to women who did not receive a version attempt (57% versus 87%; RR 0.66 (0.62-0.70)). Women with a cephalic presentation after ECV compared to women with a spontaneous cephalic presentation had a decreased risk for instrumental vaginal childbirth (RR 0.52 (95% CI 0.29-0.94)) and an increased risk of overall caesarean childbirth (RR 1.7 (95%CI 1.2-2.5)). women who had a successful ECV are at increased risk for a caesarean childbirth but overall, ECV is an important tool to reduce the caesarean rate. ECV is an important tool to reduce the caesarean section rates. Copyright © 2016. Published by Elsevier Ltd.

  12. Cephalic region war injuries in children: Experience in French NATO hospital in Kabul Afghanistan.

    Science.gov (United States)

    Chehab, Hussam El; Agard, Emilie; Dot, Corinne

    2018-06-09

    The NATO KAIA Hospital (Kabul International Airport), under French command, provided medical support for NATO forces in the Kabul region from 2009 to 2014. Medical assistance to civilians was an additional mission which included support for children who were war injured. The objective of this study was to analyze characteristics of cephalic injuries in children victims of war trauma. A retrospective study was conducted and commenced with the hospital opening (July 2009) to March 2012 on all children (<15years) with war trauma. We distinguished cephalic lesions in cranial (neuro-surgical), ophthalmological and neck regions. We analyzed mechanism, region, severity score, surgeries and resuscitation efforts. 217 children were operated on with 81 war traumas (mean age 10.2years). 36 children (44.4%) had a cephalic injury. 52.9% of the injured had an ophthalmological injury, 38.2% a cranial region injury and 29.4% a neck lesion. Mortality rate was 5.6% (1 hemorrhagic shock and 1 cerebral wound) in this cephalic lesion group. Ophthalmic injuries were the most common of cephalic injuries; 19 children of which 7 had a bilateral injury (26 eyes). In this group, fragmentary injuries were the most frequent (64% of eyes). In cerebral lesion group, the lesions were linked to a bullet or a shrapnel in 9 of 13 children. This mechanism systematically caused a crania-cerebral wound. Explosion (fragmentary and shrapnel) was the most important in the neck lesions (7 children of 10). The cephalic lesions were the second most common region in children during our experience in Afghanistan. Lack of protection (helmet) in children may explain the frequency of cephalic wounds. Copyright © 2018 Elsevier Ltd. All rights reserved.

  13. Effect of Oral Hydration on External Cephalic Version at Term.

    Science.gov (United States)

    Zobbi, Virna Franca; Nespoli, Antonella; Spreafico, Elisa; Recalcati, Roberta; Loi, Federica; Scian, Antonietta; Galimberti, Stefania

    To evaluate the effect of oral hydration on the success rate of external cephalic version (ECV). Randomized controlled and single-blind trial. Academic tertiary hospital with approximately 3,000 births annually. One hundred sixty-four women at a gestational age of at least 37 weeks with breech-presenting fetuses and normal amniotic fluid indexes (AFIs). Participants were randomly assigned to drink 2000 ml or no more than 100 ml of water in the 2 hours before undergoing ECV. The AFIs were assessed before and after treatment by the same sonographer, who was blinded to the treatment group. Data were collected on relevant maternal and fetal characteristics and ECV success. The mean AFI after hydration was significantly greater than that in the control group (15.5 cm vs. 13.4 cm, p = .003). The ECV success rate was 53.7% in the hydration group and 46.3% in the control group (odds ratio: 1.34, 95% confidence interval [0.69, 2.59]; p = .349). Hydration was well tolerated and there were no serious adverse events. Oral hydration significantly increased the AFIs but did not affect the success rate of ECVs. Copyright © 2017 AWHONN, the Association of Women's Health, Obstetric and Neonatal Nurses. Published by Elsevier Inc. All rights reserved.

  14. Patient satisfaction with childbirth after external cephalic version.

    Science.gov (United States)

    Bogner, Gerhard; Hammer, Barbara Eva; Schausberger, Christiane; Fischer, Thorsten; Reisenberger, Klaus; Jacobs, Volker

    2014-03-01

    To assess acceptance and impact of external cephalic version (ECV) for breech presentation at term on maternal satisfaction with childbirth. Retrospective study on n = 131 women with breech presentation comparing maternal satisfaction after ECV and consecutive childbirth (n = 66; 50.4% of these successful attempts in n = 33; 50%) against the group without ECV and primary caesarean section (CS) (n = 65; 49.6%) instead using a questionnaire. Women with successful ECV tolerated side effects of the intervention better than after unsuccessful ECV (pain, tocolytics, mental and physical state, for all p version were more satisfied with childbirth than women with planned CS (p = 0.05). Women with version attempts tend to perceive childbirth as being less problematic with fewer complications (9.5 vs. 19%, p = 0.12). Unsuccessful ECVs had no negative impact on satisfaction with childbirth (p = 0.072). Attempting ECV seems to be an option for increasing the rate of vaginal births with breech presentation without negative impact on maternal satisfaction regarding consecutive childbirth.

  15. Improving external cephalic version for foetal breech presentation.

    Science.gov (United States)

    Zandstra, H; Mertens, H J M M

    2013-01-01

    If success rate of external cephalic version (ECV) increases, the rate of primary caesarean sections -declines. The aims of this retrospective cohort study were to evaluate the ECV and to identify factors associated with the success rate of ECV for breech presentation at term. The second aim of this study was to analyse the outcome of labour of all patients with a foetus in breech near term. All women with a foetus in breech near or at term were included. Logistic regression analyses were -performed to identify the association between patient characteristics and success rate of ECV. The overall rate of successful ECV's was 19%. Foetal and maternal complications after ECV were negligible. BMI, type of breech and amount of amniotic fluid were significantly correlated with a successful ECV. The rate of primary caesarean sections for the group of patients who underwent an ECV was lower than the rate in the group who did not (52.9% vs. 79.6%). The rate of spontaneous deliveries was increased after ECV (36% versus 12%). After successful ECV the rate of spontaneous deliveries was 75%; after unsuccessful ECV 26.8%. The overall rate of successful ECV was low (19%). BMI, type of breech and amount of amniotic fluid were significantly correlated with a successful ECV. The rate of primary caesarean sections was significantly lower in patients with ECV (52.9% versus 79.6%). The rate of spontaneous deliveries was significantly higher (36% -versus 12%).

  16. The Role of Taste in Cephalic Phase of Insulin Secretion

    Directory of Open Access Journals (Sweden)

    M. Dušková

    2013-01-01

    Full Text Available The effect of a short gustatory signal of a sweet solution was tested on 15 young male volunteers. The experiment consisted of mouth rinsing with either a sucrose or aspartate solution or pure water as a placebo. Blood was then taken in short intervals of 0, 5, 10, 15 and 20 min. Blood glucose, C-peptide, insulin and cortisol were determined. While C-peptide and glucose were unaffected, a short-term increase in insulin was observed after the sucrose, but not after the aspartate or placebo. The increase in insulin was significant, though it amounted to only 0.5 mIU/l and lasted approx. 15 min reaching then the starting value. The decline of cortisol level within 20 min of the experiment was approx. 40 nmol/l, although it was also observed after aspartate or placebo mouth rinsing and was probably caused by stress factors or anticipation. In conclusion, the contribution of taste to the cephalic phase of insulin secretion is small yet significant, and mouth rinsing with 5% sucrose causes an insulin increase of just under 1 IU/l, which returns to starting level within 15 min.

  17. The relation between umbilical cord characteristics and the outcome of external cephalic version.

    Science.gov (United States)

    Kuppens, Simone M I; Waerenburgh, Evelyne R; Kooistra, Libbe; van der Donk, Riet W P; Hasaart, Tom H M; Pop, Victor J M

    2011-05-01

    Umbilical cords of fetuses in breech presentation differ in length and coiling from their cephalic counterparts and it might be hypothesised that these cord characteristics may in turn affect ECV outcome. To investigate the relation between umbilical cord characteristics and the outcome of external cephalic version (ECV). Prospective cohort study. Women (>35 weeks gestation) with a singleton fetus in breech presentation, suitable for external cephalic version. Demographic, lifestyle and obstetrical parameters were assessed at intake. ECV success was based on cephalic presentation on ultrasound post-ECV. Umbilical cord length (UCL) and umbilical coiling index (UCI) were measured after birth. The relation between umbilical cord characteristics (cord length and coiling) and the success of external cephalic version. ECV success rate was overall 79/146 (54%), for multiparas 37/46(80%) and for nulliparas 42/100 (42%). Multiple logistic regression showed that UCL (OR: 1.04, CI: 1.01-1.07), nulliparity (OR: 0.20, CI: 0.08-0.51), frank breech (OR: 0.37, 95% CI: 0.15-0.90), body mass index (OR: 0.85, CI: 0.76-0.95), placenta anterior (OR: 0.27, CI: 0.12-0.63) and birth weight (OR: 1.002, CI: 1.001-1.003) were all independently related to ECV success. Umbilical cord length is independently related to the outcome of ECV, whereas umbilical coiling index is not. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. External cephalic version in premature rupture of membranes: a systematic review.

    Science.gov (United States)

    Quist-Nelson, Johanna; Landers, Kathryn; McCurdy, Rebekah; Berghella, Vincenzo

    2017-09-01

    External cephalic version (ECV) increases the likelihood of a vaginal delivery in patients with breech presentation. Our objective was to determine the rate of cephalic vaginal delivery in women undergoing ECV after PROM. We performed a systematic review of all case reports, case series and clinical trials of patients undergoing an ECV after PROM ≥ 24 weeks. Maternal demographics and outcome data were obtained. The primary outcome was rate of cephalic vaginal delivery. Statistical analysis was performed for continuous outcomes by calculating mean and standard deviations for appropriate variables. The systematic review yielded six papers with 13 case reports and no clinical trials of ECV after PROM. The rate of success to cephalic presentation was 46.1% (six of 13 cases), with a subsequent vaginal delivery rate of 23.1% (three of 13 cases). The rate of umbilical cord prolapse was 33.3% (two of six cases). ECV after PROM has been reported in 13 cases in the literature. For the cases reported, 46.1% of ECV were successful in turning to cephalic position, but only 23.1% resulted in a vaginal delivery. There was a 33.3% incidence of umbilical cord prolapse. Given the high rate of umbilical cord prolapse, it would be imperative to offer an ECV in the setting of PROM only at an institution that has the ability to perform the indicated emergent cesarean delivery and only after appropriate counseling.

  19. "CEPHALIC VEIN ANATOMY IN ANTECUBITAL FOSSA DURING THE CONSTRUCTION OF ARTERIOVENOUS FISTULA"

    Directory of Open Access Journals (Sweden)

    S. M. Alamshah

    2004-08-01

    Full Text Available In order to create an effective arteriovenous fistula (AVF in patients with sustained chronic renal failure (CRF, surgeons need to become familiar with various anatomical variations of venous structures in the operating field. Because of variety and different types of cubital venous anatomies, there is more than a 90% possibility of creating suitable AVFs in the cubital fossa , but in the wrist and forearm, due to old injections and thrombophlebitis, there is less chance to do so. Since cephalic vein is the main venous conduit for constructing an AVF in the antecubital region, this study focuses on the various anatomical variations of cephalic vein and its communicating branches. We studied the cubital cephalic anatomy of 103 patients with CRF during construction of an AVF from July 1999 to June 2001. Five types of cephalic vein anatomy were seen: type A (44.66%, type B (30.1%, type C (18.44%, type D (3.88% and type E (2.29% in 39 right and 64 left arms. Seventy-six anastomoses were performed to brachial trunk, 25 to the radial and 2 to the ulnar artery. Eleven cases with progressive swelling after AVF were uneventfully cured by hand elevation. No infection, false aneurysm, venous hypertension or steal syndrome was detected. In order to obtain the best results and select appropriate operative technique for reliable vascular access in CRF, it is necessary to understand the anatomical variety of cephalic vein.

  20. Fear for external cephalic version and depression: predictors of successful external cephalic version for breech presentation at term?

    Science.gov (United States)

    Ciliacus, Emily; van der Zalm, Marieke; Truijens, Sophie E; Hasaart, Tom H; Pop, Victor J; Kuppens, Simone M

    2014-03-12

    Objective was to determine whether fear for external cephalic version (ECV) and depression are associated with the success rate of ECV in women with a breech presentation at term. Prospective study conducted in the Catharina Hospital Eindhoven between October 2007 and May 2012. Participants fulfilled The Edinburgh Depression Scale (EDS) questionnaire and expressed their degree of fear on a visual analogue scale from one to ten before ECV. Obstetric factors were evaluated as well. Primary outcome was the relation between psychological factors (fear for ECV and depression EDS scores) and ECV success rate. Secondary outcome was a possible relation between fear for ECV and increased abdominal muscle tension. The overall success rate was 55% and was significantly lower (p < 0.001) in nulliparous women (44.3%) compared with parous women (78.0%). Fear for ECV and depression EDS-scores were not related with ECV success rate. Parity, placental location, BMI and engagement of the fetal breech were obstetric factors associated with ECV outcome. There was no relation between fear for ECV and abdominal muscle tone. Fear for ECV and depression were not related with ECV success rate in this study. Engagement of the fetal breech was the most important factor associated with a successful ECV. The Eindhoven Breech Intervention Study, NCT00516555.

  1. Prevalence, outcome, and women’s experiences of external cephalic version in a low-risk population.

    NARCIS (Netherlands)

    Rijnders, M.; Offerhaus, P.; Dommelen, P. van; Wiegers, T.; Buitendijk, S.

    2010-01-01

    BACKGROUND: Until recently, external cephalic version to prevent breech presentation at birth was not widely accepted. The objective of our study was to assess the prevalence, outcomes, and women's experiences of external cephalic version to improve the implementation of the procedure in the

  2. External cephalic version for breech presentation at term

    International Nuclear Information System (INIS)

    Rauf, B.; Hassan, L.

    2007-01-01

    To assess the success rate of External Cephalic Version (ECV) at term and its effects on measures of pregnancy outcome. A total of 40 patients were offered ECV over a period of fourteen months. All singleton breech presentations with an otherwise normal antenatal course between 36-41 weeks of gestation were included in the study. Exclusion criteria included contraindications to ECV i.e. multiple pregnancy, oligohydramnios, growth retardation, antepartum hemorrhage, rupture of membranes toxemias of pregnancy, non-reassuring fetal monitoring pattern, previous uterine scar, bad obstetric history, any contraindication to vaginal delivery, labour and patient wishes after thorough counseling. Overall success rate of the procedure and its effect on maternal and fetal outcome was determined. Significance of results was determined using Chi-square test. A total of 40 patients were recruited for the trial. Overall success rate was 67.5% with only 30% being primi-gravida (p<0.05). Multi-gravida showed higher success rate of 80%. Following successful ECV, spontaneous vaginal delivery was attained in 77.7% (n=21), while caesarean section was performed due to various indications in about 6 cases (p<0.05). Following failed version, 61.5% (n=8) had elective C/S and only 5 delivered vaginally. Route of delivery did not affect the perinatal outcome except for congenital abnormalities. Following successful ECV, there was only one stillbirth. Overall live births associated with successful version was 96.2% (p<0.05), while in failed version, there were no fetal deaths. ECV at term appears to be a useful procedure to reduce the number and associated complications of term breech presentation. It is safe for the mother and the fetus and helps to avoid a significant number of caesarean sections. (author)

  3. The benefit of external cephalic version with tocolysis as a routine procedure in late pregnancy

    DEFF Research Database (Denmark)

    Thunedborg, P; Fischer-Rasmussen, W; Tollund, L

    1991-01-01

    The effectiveness of external cephalic version with tocolysis when routinely used in the 37th week of gestation is reported. The procedure had earlier been ruled out in our department, was found effective in a prospective study, and afterwards settled as a routine. Among 1038 women with single...... breech presentation, 882 could be offered an attempt of external cephalic version during the period 1982-1988. Attempt of version was carried out in 316 women resulting in a vertex presentation at delivery in 100. The success rate on average was 35%. The estimated reduction of breech deliveries was 100...... serious complications were associated with the procedure. Two cases of intra-uterine fetal death occurred 2 and 5 weeks, respectively, after successful, uncomplicated version to vertex presentation. No obvious connection with the external cephalic version could be demonstrated. The effectiveness...

  4. Prevalence, outcome, and women's experiences of external cephalic version in a low-risk population.

    Science.gov (United States)

    Rijnders, Marlies; Offerhaus, Pien; van Dommelen, Paula; Wiegers, Therese; Buitendijk, Simone

    2010-06-01

    Until recently, external cephalic version to prevent breech presentation at birth was not widely accepted. The objective of our study was to assess the prevalence, outcomes, and women's experiences of external cephalic version to improve the implementation of the procedure in the Netherlands. A prospective cohort study was conducted of 167 women under the care of a midwife with confirmed breech presentation at a gestational age of 33 completed weeks or more. Between June 2007 and January 2008, 167 women with a confirmed breech presentation were offered an external cephalic version. Of this group, 123 women (73.7%, 95% CI: 65.5-80.5) subsequently received the version. These women had about a ninefold increased probability of a cephalic presentation at birth compared with women who did not undergo a version (relative risk [RR]: 8.8, 95% CI: 2.2-34.8). The chance of a vaginal birth after an external cephalic version was almost threefold (RR: 2.7, 95% CI: 1.5-5.0). The success rate was 39 percent, although considerable differences existed associated with region and parity. Ninety-four percent of women with a successful version rated it as a good experience compared with 71 percent of women who had a failed version (p = 0.015). Significant pain during the version was experienced by 34 percent of women, of whom 18 percent also experienced fear during the version, compared with no women who reported little or no pain (p = 0.006). Women who reported significant pain or fear during the version experienced the version more negatively (OR: 6.0, 95% CI: 3.3-12.2 and OR: 2.7, 95% CI: 1.1-6.0, respectively). One in every four women with a breech presentation in independent midwifery care did not receive an external cephalic version. Of the women who received a version one third experienced significant pain during the procedure. Considerable regional variation in success rate existed.

  5. Delivery mode and neonatal outcome after a trial of external cephalic version (ECV): a prospective trial of vaginal breech versus cephalic delivery.

    Science.gov (United States)

    Reinhard, Joscha; Sänger, Nicole; Hanker, Lars; Reichenbach, Lena; Yuan, Juping; Herrmann, Eva; Louwen, Frank

    2013-04-01

    To examine the delivery mode and neonatal outcome after a trial of external cephalic version (ECV) procedures. This is an interim analysis of an ongoing larger prospective off-centre randomised trial, which compares a clinical hypnosis intervention against neuro-linguistic programming (NLP) of women with a singleton breech foetus at or after 37(0/7) (259 days) weeks of gestation and normal amniotic fluid index. Main outcome measures were delivery mode and neonatal outcome. On the same day after the ECV procedure two patients (2 %), who had unsuccessful ECVs, had Caesarean sections (one due to vaginal bleeding and one due to pathological CTG). After the ECV procedure 40.4 % of women had cephalic presentation (n = 38) and 58.5 % (n = 55) remained breech presentation. One patient remained transverse presentation (n = 1; 1.1 %). Vaginal delivery was observed by 73.7 % of cephalic presentation (n = 28), whereas 26.3 % (n = 10) had in-labour Caesarean sections. Of those, who selected a trial of vaginal breech delivery, 42.4 % (n = 14) delivered vaginally and 57.6 % (n = 19) delivered via Caesarean section. There is a statistically significant difference between the rate of vaginal birth between cephalic presentation and trial of vaginal breech delivery (p = 0.009), however, no difference in neonatal outcome was observed. ECV is a safe procedure and can reduce not only the rate of elective Caesarean sections due to breech presentation but also the rate of in-labour Caesarean sections even if a trial of vaginal breech delivery is attempted.

  6. Determinants of pain perception after external cephalic version in pregnant women

    NARCIS (Netherlands)

    Truijens, Sophie; Zalm, van der Marieke; Pop, V.J.M.; Kuppens, S.M.I.

    2014-01-01

    A considerable proportion of pregnant women with a fetus in breech position refuses external cephalic version (ECV), with fear of pain as important barrier. As a consequence, they are at high risk for caesarean section at term. The current study investigated determinants of pain perception during

  7. Risk factors for cesarean section and instrumental vaginal delivery after successful external cephalic version.

    Science.gov (United States)

    de Hundt, Marcella; Vlemmix, Floortje; Bais, Joke M J; de Groot, Christianne J; Mol, Ben Willem; Kok, Marjolein

    2016-01-01

    Aim of this article is to examine if we could identify factors that predict cesarean section and instrumental vaginal delivery in women who had a successful external cephalic version. We used data from a previous randomized trial among 25 hospitals and their referring midwife practices in the Netherlands. With the data of this trial, we performed a cohort study among women attempting vaginal delivery after successful ECV. We evaluated whether maternal age, gestational age, parity, time interval between ECV and delivery, birth weight, neonatal gender, and induction of labor were predictive for a vaginal delivery on one hand or a CS or instrumental vaginal delivery on the other hand. Unadjusted and adjusted odds ratios were calculated with univariate and multivariate logistic regression analysis. Among 301 women who attempted vaginal delivery after a successful external cephalic version attempt, the cesarean section rate was 13% and the instrumental vaginal delivery rate 6%, resulting in a combined instrumental delivery rate of 19%. Nulliparity increased the risk of cesarean section (OR 2.7 (95% CI 1.2-6.1)) and instrumental delivery (OR 4.2 (95% CI 2.1-8.6)). Maternal age, gestational age at delivery, time interval between external cephalic version and delivery, birth weight and neonatal gender did not contribute to the prediction of failed spontaneous vaginal delivery. In our cohort of 301 women with a successful external cephalic version, nulliparity was the only one of seven factors that predicted the risk for cesarean section and instrumental vaginal delivery.

  8. Delivery after external cephalic version, is there an increased rate of cesarian section?

    Science.gov (United States)

    Lago Leal, Victor; Pradillo Aramendi, Tamara; Nicolas Montero, Estefania; Ocaña Martínez, Vanesa; Del Barrio Fernández, Pablo; Martínez-Cortés, Luis

    2016-04-01

    The aim of this study was to compare the obstetric outcomes after successful external cephalic version (cases) with a group of pregnant women with a spontaneous cephalic fetal position at delivery (controls). Retrospective review of the cohort of study was performed at the University Hospital of Getafe (Madrid, Spain) between January 2012 and January 2013. 1516 patients (48 cases; 1468 controls). We compared the type of delivery in pregnant women after ECV performed successfully (cases) with spontaneous cephalic presentations (controls). Pregnancies with vaginal delivery contraindicated, elective cesarean section (CS) justified by maternal disease, multiple pregnancies, or pregnancies below 37 weeks were excluded. Maternal age, BMI, parity, gestational age at delivery, and onset of labor (spontaneous or induced) were controlled. Prevalence of CS and operative delivery in both groups. Women who underwent a successful ECV had a significantly higher CS rate compared with the women of the control group (12/48 [25%] vs. 202/1468 [13.76%]; P=0.028). There was no difference in the rate of operative delivery (6/48 [12.5%] vs. 177/1468 [12.05%] P=0.92). Deliveries following a successful ECV are associated with an increased CS rate compared with deliveries of fetuses with spontaneous cephalic presentations.

  9. External Validation of a Prediction Model for Successful External Cephalic Version

    NARCIS (Netherlands)

    de Hundt, Marcella; Vlemmix, Floortje; Kok, Marjolein; van der Steeg, Jan W.; Bais, Joke M.; Mol, Ben W.; van der Post, Joris A.

    2012-01-01

    We sought external validation of a prediction model for the probability of a successful external cephalic version (ECV). We evaluated the performance of the prediction model with calibration and discrimination. For clinical practice, we developed a score chart to calculate the probability of a

  10. Risk factors for cesarean section and instrumental vaginal delivery after successful external cephalic version

    NARCIS (Netherlands)

    de Hundt, Marcella; Vlemmix, Floortje; Bais, Joke M. J.; de Groot, Christianne J.; Mol, Ben Willem; Kok, Marjolein

    2016-01-01

    Aim of this article is to examine if we could identify factors that predict cesarean section and instrumental vaginal delivery in women who had a successful external cephalic version. We used data from a previous randomized trial among 25 hospitals and their referring midwife practices in the

  11. Mode of delivery after successful external cephalic version: a systematic review and meta-analysis

    NARCIS (Netherlands)

    de Hundt, Marcella; Velzel, Joost; de Groot, Christianne J.; Mol, Ben W.; Kok, Marjolein

    2014-01-01

    To assess the mode of delivery in women after a successful external cephalic version by performing a systematic review and meta-analysis. We searched MEDLINE, Embase, ClinicalTrials.gov, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library for studies reporting on the

  12. Nifedipine as a uterine relaxant for external cephalic version: a randomized controlled trial

    NARCIS (Netherlands)

    Kok, Marjolein; Bais, Joke M.; van Lith, Jan M.; Papatsonis, Dimitri M.; Kleiverda, Gunilla; Hanny, Dahrs; Doornbos, Johannes P.; Mol, Ben W.; van der Post, Joris A.

    2008-01-01

    OBJECTIVE: To estimate the effectiveness of nifedipine as a uterine relaxant during external cephalic version to correct breech presentation. METHODS: In this randomized, double-blind, placebo-controlled trial, women with a singleton fetus in breech presentation and a gestational age of 36 weeks or

  13. Maternal thyroid function and the outcome of external cephalic version: a prospective cohort study

    NARCIS (Netherlands)

    Kuppens, S.M.I.; Kooistra, L.; Hasaart, T.H.M.; Donk, M.W.; Vader, H.; Oei, S.G.; Pop, V.J.

    2011-01-01

    Background To investigate the relation between maternal thyroid function and the outcome of external cephalic version (ECV) in breech presentation. Methods Prospective cohort study in 141 women (= 35 weeks gestation) with a singleton fetus in breech. Blood samples for assessing thyroid function were

  14. Determinants of pain perception after external cephalic version in pregnant women

    NARCIS (Netherlands)

    Truijens, Sophie E. M.; van der Zalm, Marieke; Pop, Victor J. M.; Kuppens, S.M.

    Objective A considerable proportion of pregnant women with a fetus in breech position refuses external cephalic version (ECV), with fear of pain as important barrier. As a consequence, they are at high risk for caesarean section at term. The current study investigated determinants of pain perception

  15. Contraindications for external cephalic version in breech position at term: a systematic review

    NARCIS (Netherlands)

    Rosman, Ageeth N.; Guijt, Aline; Vlemmix, Floortje; Rijnders, Marlies; Mol, Ben W. J.; Kok, Marjolein

    2013-01-01

    External cephalic version (ECV) is a safe and effective intervention that can prevent breech delivery, thus reducing the need for cesarean delivery. It is recommended in national guidelines. These guidelines also mention contraindications for ECV, and thereby restrict the application of ECV. We

  16. Contraindications for external cephalic version in breech position at term: A systematic review

    NARCIS (Netherlands)

    Rosman, A.N.; Guijt, A.; Vlemmix, F.; Rijnders, M.; Mol, B.W.J.; Kok, M.

    2013-01-01

    Objective. External cephalic version (ECV) is a safe and effective intervention that can prevent breech delivery, thus reducing the need for cesarean delivery. It is recommended in national guidelines. These guidelines also mention contraindications for ECV, and thereby restrict the application of

  17. Successful external cephalic version after amnioinfusion in a patient with preterm premature rupture of membranes.

    Science.gov (United States)

    Buek, John D; McVearry, Ingrid; Lim, Elaine; Landy, Helain; Afriyie-Gray, Akua

    2005-06-01

    After hospitalization subsequent to preterm premature rupture of membranes at 29 weeks, our patient was scheduled for induction of labor at 34 weeks. When the fetus was found to be breech with oligohydramnios, amnioinfusion was performed to facilitate external cephalic version, and this successful procedure enabled the patient to deliver vaginally.

  18. Unintentional arterial puncture during cephalic vein cannulation: case report and anatomical study

    NARCIS (Netherlands)

    Lirk, P.; Keller, C.; Colvin, J.; Colvin, H.; Rieder, J.; Maurer, H.; Moriggl, B.

    2004-01-01

    The cephalic antebrachial vein is often used for venous access. However, superficial radial arteries of the forearm are known and unintentional arterial puncture can result from attempts to cannulate the lateral veins of the arm. Accidental puncture of a superficial radial artery during peripheral

  19. Prediction of neonatal metaboic acidos in women with a singleton term pregnancy in cephalic presentation

    NARCIS (Netherlands)

    Westerhuis, M.E.M.H.; Schuit, E.; Kwee, A.; Zuithoff, N.P.A.; Groenwold, R.H.H.; Akker, van den E.S.A.; Beek, van E.; Dessel, van H.J.H.M.; Drogtrop, A.P.; Geijn, van H.P.; Graziosi, G.C.M.; Lith, van J.M.M.; Nijhuis, J.G.; Oei, S.G.; Oosterbaan, H.P.; Porath, M.M.; Rijnders, R.J.P.; Schuitemaker, N.W.E.; Wijnberger, L.D.E.; Willekes, C.; Wouters, M.G.A.J.; Visser, G.H.A.; Mol, B.W.J.; Moons, K.G.M.

    2012-01-01

    We sought to predict neonatal metabolic acidosis at birth using antepartum obstetric characteristics (model 1) and additional characteristics available during labor (model 2). In 5667 laboring women from a multicenter randomized trial that had a high-risk singleton pregnancy in cephalic presentation

  20. Measurement of hemodynamics during postural changes using a new wearable cephalic laser blood flowmeter.

    Science.gov (United States)

    Fujikawa, Tetsuya; Tochikubo, Osamu; Kura, Naoki; Kiyokura, Takanori; Shimada, Junichi; Umemura, Satoshi

    2009-10-01

    Patients with orthostatic hypotension have pathologic hemodynamics related to changes in body posture. A new cephalic laser blood flowmeter that can be worn on the tragus to investigate the hemodynamics upon rising from a sitting or squatting posture was developed. The relationship between cephalic hemodynamics and cerebral ischemic symptoms in 63 subjects in a sitting, squatting, and standing positions using the new device was evaluated. Transient decrease in blood pressure within 15 s after rising to an erect position possibly causes dizziness, syncope, and fall. Subjects exhibiting dizziness upon standing showed a significant decrease in the cephalic blood flow (CBF) and indirect beat-to-beat systolic blood pressure, as monitored by the Finometer, and a significant correlation was observed between the drop ratio (drop value on rising/mean value in the squatting position) of CBF and that of systolic blood pressure. This new wearable CBF-meter is potentially useful for estimating cephalic hemodynamics and objectively diagnosing cerebral ischemic symptoms of subjects in a standing posture.

  1. [Transposition of the cephalic vein in free flap breast reconstruction: Technical note].

    Science.gov (United States)

    Silhol, T; Suffee, T; Hivelin, M; Lantieri, L

    2018-02-01

    Free flaps have become a reliable practice for breast reconstruction. However, the venous congestion is still the most frequent reason of flap failure. It is due to bad quality of the internal mammary veins, a preferential superficial venous outflow of the flap or due to venous thrombosis. The transposition of the cephalic vein could useful in some cases. We describe the surgical technique and suggest an intraoperative algorithm. Seventeen patients (15 DIEP and 2 PAP) were included. Twenty nine point four percent had an unusable internal mammary vein, 23.5% a preferential superficial venous outflow and 47.1% a venous thrombosis. The length of the cephalic vein dissected varied from 15 to 25cm. The mean time of dissection was 39min. There was no flap failure after cephalic vein transposition. The sequelae were one or two scars on the arm without any functional morbidity. The transposition of the cephalic vein is a reliable, less morbid alternative in case of bad quality internal mammary vein with a good quality internal mammary artery, in case of an additional venous outflow necessity or in case of venous thrombosis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Atosiban versus fenoterol as a uterine relaxant for external cephalic version: randomised controlled trial.

    Science.gov (United States)

    Velzel, Joost; Vlemmix, Floortje; Opmeer, Brent C; Molkenboer, Jan F M; Verhoeven, Corine J; van Pampus, Mariëlle G; Papatsonis, Dimitri N M; Bais, Joke M J; Vollebregt, Karlijn C; van der Esch, Liesbeth; Van der Post, Joris A M; Mol, Ben Willem; Kok, Marjolein

    2017-01-26

     To compare the effectiveness of the oxytocin receptor antagonist atosiban with the beta mimetic fenoterol as uterine relaxants in women undergoing external cephalic version (ECV) for breech presentation.  Multicentre, open label, randomised controlled trial.  Eight hospitals in the Netherlands, August 2009 to May 2014.  830 women with a singleton fetus in breech presentation and a gestational age of more than 34 weeks were randomly allocated in a 1:1 ratio to either 6.75 mg atosiban (n=416) or 40 μg fenoterol (n=414) intravenously for uterine relaxation before ECV.  The primary outcome measures were a fetus in cephalic position 30 minutes after the procedure and cephalic presentation at delivery. Secondary outcome measures were mode of delivery, incidence of fetal and maternal complications, and drug related adverse events. All analyses were done on an intention-to-treat basis.  Cephalic position 30 minutes after ECV occurred significantly less in the atosiban group than in the fenoterol group (34% v 40%, relative risk 0.73, 95% confidence interval 0.55 to 0.93). Presentation at birth was cephalic in 35% (n=139) of the atosiban group and 40% (n=166) of the fenoterol group (0.86, 0.72 to 1.03), and caesarean delivery was performed in 60% (n=240) of women in the atosiban group and 55% (n=218) in the fenoterol group (1.09, 0.96 to 1.20). No significant differences were found in neonatal outcomes or drug related adverse events.  In women undergoing ECV for breech presentation, uterine relaxation with fenoterol increases the rate of cephalic presentation 30 minutes after the procedure. No statistically significant difference was found for cephalic presentation at delivery.  Dutch Trial Register, NTR 1877. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  3. External cephalic version for breech presentation with or without spinal analgesia in nulliparous women at term: a randomized controlled trial.

    Science.gov (United States)

    Weiniger, Carolyn F; Ginosar, Yehuda; Elchalal, Uriel; Sharon, Einav; Nokrian, Malka; Ezra, Yossef

    2007-12-01

    To compare the success of external cephalic version using spinal analgesia with no analgesia among nulliparas. A prospective randomized controlled trial was performed in a tertiary referral center delivery suite. Nulliparous women at term requesting external cephalic version for breech presentation were randomized to receive spinal analgesia (7.5 mg bupivacaine) or no analgesia before the external cephalic version. An experienced obstetrician performed the external cephalic version. Primary outcome was successful conversion to vertex presentation. Seventy-four women were enrolled, and 70 analyzed (36 spinal, 34 no analgesia). Successful external cephalic version occurred among 24 of 36 (66.7%) women randomized to receive spinal analgesia compared with 11 of 34 (32.4%) without, P=.004 (95% confidence interval [CI] of the difference: 0.0954-0.5513). External cephalic version with spinal analgesia resulted in a lower visual analog pain score, 1.76+/-2.74 compared with 6.84+/-3.08 without, Pexternal cephalic version success was 4.0-fold higher when performed with spinal analgesia P=.02 (95% CI, odds ratio [OR] 1.2-12.9). Complete breech presentation before attempting external cephalic version increased the odds of success 8.2-fold, P=.001 (95% CI, OR 2.2-30.3). Placental position, estimated fetal weight, and maternal weight did not contribute to the success rate when spinal analgesia was used. There were no cases of placental abruption or fetal distress. Administration of spinal analgesia significantly increases the success rate of external cephalic version among nulliparous women at term, which allows possible normal vaginal delivery. ClinicalTrials.gov, www.clinicaltrials.gov, NCT00119184 I.

  4. Ultrasonographic evaluation of myometrial thickness and prediction of a successful external cephalic version.

    Science.gov (United States)

    Buhimschi, Catalin S; Buhimschi, Irina A; Wehrum, Mark J; Molaskey-Jones, Sherry; Sfakianaki, Anna K; Pettker, Christian M; Thung, Stephen; Campbell, Katherine H; Dulay, Antonette T; Funai, Edmund F; Bahtiyar, Mert O

    2011-10-01

    To test the hypothesis that myometrial thickness predicts the success of external cephalic version. Abdominal ultrasonographic scans were performed in 114 consecutive pregnant women with breech singletons before an external cephalic version maneuver. Myometrial thickness was measured by a standardized protocol at three sites: the lower segment, midanterior wall, and the fundal uterine wall. Independent variables analyzed in conjunction with myometrial thickness were: maternal age, parity, body mass index, abdominal wall thickness, estimated fetal weight, amniotic fluid index, placental thickness and location, fetal spine position, breech type, and delivery outcomes such as final mode of delivery and birth weight. Successful version was associated with a thicker ultrasonographic fundal myometrium (unsuccessful: 6.7 [5.5-8.4] compared with successful: 7.4 [6.6-9.7] mm, P=.037). Multivariate regression analysis showed that increased fundal myometrial thickness, high amniotic fluid index, and nonfrank breech presentation were the strongest independent predictors of external cephalic version success (Pexternal cephalic versions (fundal myometrial thickness: odds ratio [OR] 2.4, 95% confidence interval [CI] 1.1-5.2, P=.029; amniotic fluid index: OR 2.8, 95% CI 1.3-6.0, P=.008). Combining the two variables resulted in an absolute risk reduction for a failed version of 27.6% (95% CI 7.1-48.1) and a number needed to treat of four (95% CI 2.1-14.2). Fundal myometrial thickness and amniotic fluid index contribute to success of external cephalic version and their evaluation can be easily incorporated in algorithms before the procedure. III.

  5. The Cost Implications in Ontario, Alberta, and British Columbia of Early Versus Delayed External Cephalic Version in the Early External Cephalic Version 2 (EECV2) Trial.

    Science.gov (United States)

    Ahmed, Rashid J; Gafni, Amiram; Hutton, Eileen K

    2016-03-01

    According to the Early External Cephalic Version (EECV2) Trial, planning external cephalic version (ECV) early in pregnancy results in fewer breech presentations at delivery compared with delayed external cephalic version. A Cochrane review conducted after the EECV2 Trial identified an increase in preterm birth associated with early ECV. We examined whether a policy of routine early ECV (i.e., before 37 weeks' gestation) is more or less costly than a policy of delayed ECV. We undertook this analysis from the perspective of a third-party payer (Ministry of Health). We applied data, using resources reported in the EECV2 Trial, to the Canadian context using 10 hospital unit costs and 17 physician service/procedure unit costs. The data were derived from the provincial health insurance plan schedule of medical benefits in three Canadian provinces (Ontario, Alberta, and British Columbia). The difference in mean total costs between study groups was tested for each province separately. We found that planning early ECV results in higher costs than planning delayed ECV. The mean costs of all physician services/procedures and hospital units for planned ECV compared with delayed ECV were $7997.32 versus $7263.04 in Ontario (P < 0.001), $8162.82 versus $7410.55 in Alberta (P < 0.001), and $8178.92 versus $7417.04 in British Columbia (P < 0.001), respectively. From the perspective of overall cost, our analyses do not support a policy of routinely planning ECV before 37 weeks' gestation. Copyright © 2016 The Society of Obstetricians and Gynaecologists of Canada/La Société des obstétriciens et gynécologues du Canada. Published by Elsevier Inc. All rights reserved.

  6. External cephalic version among women with a previous cesarean delivery: report on 36 cases and review of the literature.

    Science.gov (United States)

    Abenhaim, Haim A; Varin, Jocelyne; Boucher, Marc

    2009-01-01

    Whether or not women with a previous cesarean section should be considered for an external cephalic version remains unclear. In our study, we sought to examine the relationship between a history of previous cesarean section and outcomes of external cephalic version for pregnancies at 36 completed weeks of gestation or more. Data on obstetrical history and on external cephalic version outcomes was obtained from the C.H.U. Sainte-Justine External Cephalic Version Database. Baseline clinical characteristics were compared among women with and without a history of previous cesarean section. We used logistic regression analysis to evaluate the effect of previous cesarean section on success of external cephalic version while adjusting for parity, maternal body mass index, gestational age, estimated fetal weight, and amniotic fluid index. Over a 15-year period, 1425 external cephalic versions were attempted of which 36 (2.5%) were performed on women with a previous cesarean section. Although women with a history of previous cesarean section were more likely to be older and para >2 (38.93% vs. 15.0%), there were no difference in gestational age, estimated fetal weight, and amniotic fluid index. Women with a prior cesarean section had a success rate similar to women without [50.0% vs. 51.6%, adjusted OR: 1.31 (0.48-3.59)]. Women with a previous cesarean section who undergo an external cephalic version have similar success rates than do women without. Concern about procedural success in women with a previous cesarean section is unwarranted and should not deter attempting an external cephalic version.

  7. External cephalic version of the term breech baboon (Papio sp.) fetus.

    Science.gov (United States)

    Barrier, Breton F; Joiner, Laura Lee Rihl; Jimenez, Joe B; Leland, M Michelle

    2007-06-01

    Breech presentation in baboons may be associated with head entrapment and stillbirth during vaginal delivery. For this reason, pregnant dams at our institution typically undergo cesarean delivery for known breech presentation, leading to problems with maternal-infant bonding and increased nursery utilization. This paper describes a simple, non-invasive technique called external cephalic version (ECV) that effectively converts the baboon breech fetus into a cephalic presentation. ECV was successful in each of seven attempted cases, with the consistent development of contractions and vaginal bleeding leading to the delivery of a healthy liveborn infant within 72 hours. ECV may offer a safe and effective alternative to cesarean section for delivery of the breech baboon fetus.

  8. Intrapartum intervention rates and perinatal outcomes following successful external cephalic version.

    Science.gov (United States)

    Basu, A; Flatley, C; Kumar, S

    2016-06-01

    To determine intrapartum and perinatal outcomes following successful external cephalic version for breech presentation at term. This was a retrospective cohort study of outcomes following successful external cephalic version in 411 women at an Australian tertiary maternity unit between November 2008 and March 2015. The study cohort was compared with a control group of 1236 women with cephalic presentation who underwent spontaneous labor. Intrapartum intervention rates and adverse neonatal outcomes were compared between both groups. The success rate of external cephalic version (ECV) was 66.4%. The spontaneous vaginal delivery rate in the study cohort was 59.4% (224/411) vs 72.8% (900/1236) in the control cohort (P<0.001). Intrapartum intervention rates (emergency cesarean section (CS) and instrumental delivery) were higher in the ECV group (38% vs 27.2%, P<0.001). Rates of emergency CS for non-reassuring fetal status (9.5%, 39/411 vs 4.4%, 54/1236, P⩽0.001) and failure to progress (13.4%, 55/411 vs 4.1%, 51/1236, P<0.001) were higher in the study cohort. Neonatal outcomes were worse in the study cohort-Apgar score <7 at 5 min (2.2%, 9/411 vs 0.6%, 8/1236, P<0.001) and abnormal cord gases (8.5%, 35/411 vs 0.2%, 3/1236, P<0.001). Rates for resuscitation at birth and admission to the neonatal intensive care unit were higher in the study cohort (6.1% vs 4.1% and 1.9% vs 1.1%, respectively) but these were not statistically significant. Labor following successful ECV is more likely to result in increased intrapartum intervention rates and poorer neonatal outcomes.

  9. The cephalic lateral line system of temperate perches (Perciformes: Percichthyidae from Argentinean Patagonia

    Directory of Open Access Journals (Sweden)

    Rocío M. Vega

    Full Text Available ABSTRACT The species of Percichthys (Percichthyidae are endemic to southern South America. Some authors have pointed out that the genus includes four valid species, based on the morphology of the head, jaws, and fins. A phylogenetic analysis published by other authors suggests that three of them are morphotypes belonging to the same species, Percichthys trucha (Valenciennes, 1833. The aim of this study is to describe for the first time the morphology of the cephalic seismosensory system of Patagonian perches, and how these characters vary in the three morphotypes, in order to provide morphological elements to analyze the taxonomy of these fish species. Comparisons of the cephalic seismosensory system between juveniles and adults were also conducted. Juvenile and adult specimens were collected in the northwestern Argentinean Patagonia. Specimens were bleached in 5% H2O2 and the canal systems of their cephalic lateral line were filled with hematoxylin. Specimens were deposited in the Museo Argentino de Ciencias Naturales Bernardino Rivadavia, Argentina. The cephalic lateral line of the studied specimens is a widened type of canal systems, is not connected to the trunk lateral line, and consists of preopercular-mandibular canal, infraorbital canal, supraorbital canal, temporal canal, supratemporal canal, and a supraorbital commisure. The number of pores increases during the ontogeny, while their diameters decrease. The number, position and size of infraorbital canal pores showed significant differences among morphotypes and juveniles. The interpopulation variation regarding the number, position, and size of pores seems to signal an ongoing process of speciation, which is the result adaptations to different environmental conditions. Our study contributes to the knowledge of the morphology of percichthids and describes for the first time the seismosensory system of temperate perches.

  10. Standards for midwife Practitioners of external cephalic version: A Delphi study

    OpenAIRE

    Walker, Shawn; Perilakalathil, Prasanth; Moore, Jenny; Gibbs, Claire; Reavell, Karen; Crozier, Kenda

    2015-01-01

    Introduction: Expansion of advanced and specialist midwifery practitioner roles across professional boundaries requires an evidence-based framework to evaluate achievement and maintenance of competency. In order to develop the role of Breech Specialist Midwife to include the autonomous performance of external cephalic version within one hospital, guidance was required on standards of training and skill development, particularly in the use of ultrasound. Methods: A three-round Delphi survey wa...

  11. [Risk of developmental dysplasia of the hip in patients subjected to the external cephalic version].

    Science.gov (United States)

    Sarmiento Carrera, Nerea; González Colmenero, Eva; Vázquez Castelo, José Luis; Concheiro Guisán, Ana; Couceiro Naveira, Emilio; Fernández Lorenzo, José Ramón

    2018-03-01

    Developmental dysplasia of the hip (DDH) refers to the spectrum of abnormalities of maturation and development of the hip. Breech presentation is associated with DDH. This risk factor can be modified by external cephalic version (ECV). The aim of this study is to evaluate the incidence of DDH in patients who successfully underwent ECV, as well as to evaluate need for these children (breech for a period during gestation) to be included in the DDH screening protocol. A prospective cohort study was conducted in the Hospital Universitario de Vigo from January 1, 2015 to December 31, 2015. It included children born in cephalic presentation after a successful ECV, as well as children born in breech presentation. They all were screened for DDH by ultrasound examination of the hip. Out of a total of 122 newborns included in the study, ECV was attempted on 67 (54.9%), of which 35 (52.2%) were successful. Out of the 14 children diagnosed with DDH, 3 of those born in cephalic presentation after a successful ECV were found to be normal on physical examination. Successful ECV is associated with a lower incidence of DDH as regards breech presentation. However, these patients should be included in the DDH screening protocol for the early detection of this disorder. Copyright © 2017 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Factors associated with the success of external cephalic version (ECV) of breech presentation at term.

    Science.gov (United States)

    Obeidat, N; Lataifeh, I; Al-Khateeb, M; Zayed, F; Khriesat, W; Amarin, Z

    2011-01-01

    To evaluate the predictors of success of ECV for breech presentation at term. A retrospective study was conducted over a 3-year period from 2005-2007, where 101 patients who had singleton breech presentation at term were undergoing external cephalic version (ECV) after 37 weeks of gestation at two major teaching hospitals in the North of Jordan. Comparative analysis was made between the successful ECV and unsuccessful ECV groups. The collected data were analysed by using statistical analysis Sudent's t-test and Mann-Whitney test as appropriate and on discrete results chi square or Fisher's exact test when appropriate. The differences were considered significant at a p value of breeches (74% vs 26%, p = 0.002), posterior placenta (38.6% vs 16.4%, p = 0.0001) and anterior fetal back (53.4% vs 34.8%, p = 0.03). Once turned the babies remained cephalic until delivery. All the 28 cases who had failed ECV had caesarean section. Among those who had a successful external cephalic version, the incidence of intrapartum caesarean section was only 8.2% which was lower than that of the average of both units caesarean rate (28%). There were no complications related to the ECV procedure in the study. Multiparity, flexed breech, posterior placenta, and anterior foetal back were the most favourable factors for successful ECV in our study. Moreover, with careful evaluation of individual predictors patient selection and success rates can be optimised.

  13. Enhanced ghrelin secretion in the cephalic phase of food ingestion in women with bulimia nervosa.

    Science.gov (United States)

    Monteleone, Palmiero; Serritella, Cristina; Scognamiglio, Pasquale; Maj, Mario

    2010-02-01

    In humans, the cephalic phase response to food ingestion consists mostly of vagal efferent activation, which promotes the secretion of entero-pancreatic hormones, including ghrelin. Since symptomatic patients with bulimia nervosa (BN) are characterized by increased vagal tone, we hypothesized an enhanced ghrelin secretion in the cephalic phase of vagal stimulation. Therefore, we investigated ghrelin response to modified sham feeding (MSF) in both BN and healthy women. Six drug-free BN women and 7 age-matched healthy females underwent MSF with initially seeing and smelling a meal, and then chewing the food without swallowing it. Blood samples were drawn immediately before and after MSF for hormone assay. Circulating ghrelin increased after MSF in both groups with BN individuals exhibiting a greater ghrelin increase, which positively correlated with the patients' weekly frequency of binge-purging. These results show for the first time an increased ghrelin secretion in the cephalic phase of vagal stimulation in symptomatic BN patients, likely resulting in a potentiation of the peripheral hunger signal, which might contribute to their aberrant binge-purging behavior. 2009 Elsevier Ltd. All rights reserved.

  14. Transposition of cephalic vein to rescue hemodialysis access arteriovenous fistula and treat symptomatic central venous obstruction

    Directory of Open Access Journals (Sweden)

    Felipe Jose Skupien

    2014-03-01

    Full Text Available It is known that stenosis or central venous obstruction affects 20 to 50% of patients who undergo placement of catheters in central veins. For patients who are given hemodialysis via upper limbs, this problem causes debilitating symptoms and increases the risk of loss of hemodialysis access. We report an atypical case of treatment of a dialysis patient with multiple comorbidities, severe swelling and pain in the right upper limb (RUL, few alternative sites for hemodialysis vascular access, a functioning brachiobasilic fistula in the RUL and severe venous hypertension in the same limb, secondary to central vein occlusion of the internal jugular vein and right brachiocephalic trunk. The alternative surgical treatment chosen was to transpose the RUL cephalic vein, forming a venous necklace at the anterior cervical region, bypassing the site of venous occlusion. In order to achieve this, we dissected the cephalic vein in the right arm to its junction with the axillary vein, devalved the cephalic vein and anastomosed it to the contralateral external jugular vein, providing venous drainage to the RUL, alleviating symptoms of venous hypertension and preserving function of the brachiobasilic fistula.

  15. Increased pain relief with remifentanil does not improve the success rate of external cephalic version: a randomized controlled trial.

    Science.gov (United States)

    Burgos, Jorge; Pijoan, José I; Osuna, Carmen; Cobos, Patricia; Rodriguez, Leire; Centeno, María del Mar; Serna, Rosa; Jimenez, Antonia; Garcia, Eugenia; Fernandez-Llebrez, Luis; Melchor, Juan C

    2016-05-01

    Our objective was to compare the effect of two pain relief methods (remifentanil vs. nitrous oxide) on the success rate of external cephalic version. We conducted a randomized open label parallel-group controlled single-center clinical trial with sequential design, at Cruces University Hospital, Spain. Singleton pregnancies in noncephalic presentation at term that were referred for external cephalic version were assigned according to a balanced (1:1) restricted randomization scheme to analgesic treatment with remifentanil or nitrous oxide during the procedure. The primary endpoint was external cephalic version success rate. Secondary endpoints were adverse event rate, degree of pain, cesarean rate and perinatal outcomes. The trial was stopped early after the second interim analysis due to a very low likelihood of finding substantial differences in efficacy (futility). The external cephalic version success rate was the same in the two arms (31/60, 51.7%) with 120 women recruited, 60 in each arm. The mean pain score was significantly lower in the remifentanil group (3.2 ± 2.4 vs. 6.0 ± 2.3; p external cephalic version-related complications. There was a trend toward a higher frequency of adverse effects in the remifentanil group (18.3% vs. 6.7%, p = 0.10), with a significantly higher incidence rate (21.7 events/100 women vs. 6.7 events/100 women with nitrous oxide, p = 0.03). All reported adverse events were mild and reversible. Remifentanil for analgesia decreased external cephalic version-related pain but did not increase the success rate of external cephalic version at term and appeared to be associated with an increased frequency of mild adverse effects. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

  16. [Fewer breech deliveries after implementation of a modified cephalic version protocol].

    Science.gov (United States)

    Kuppens, Simone M I; Francois, Anne M H; Hasaart, Tom H M; van der Donk, Maria W P; Pop, Victor J M

    2010-01-01

    To investigate the effect of implementation of a number of process policy guidelines (protocol), on the success rate of external cephalic version (ECV) for breech presentation. Prospective study. During a 3-year period (2004-2006) a standardized protocol for an ECV consultation was developed, evaluated and adapted. After implementing this modified protocol as 'process policy guidelines', the effect on the rate of successful ECV was prospectively evaluated during the period 1 January 2007-31 July 2008. Success was defined as cephalic presentation (ultrasound) immediately after ECV. A secondary outcome measure was the elective caesarean section rate for breech presentation. The rate of successful ECV increased significantly from 47% (110/236 pregnant women) in the period January 2004-December 2006 to 61% (85/139, p = 0.006) in the period January 2007-July 2008. Patient characteristics were similar in both groups, with the exception of 2 subgroups of term of version. The increase was preferentially found in nulliparous and multiparous women with frank breech. Nulliparity, frank breech, anterior placenta and low birth weight were associated with a lower success rate of ECV. The term of pregnancy at which ECV was performed did not seem to affect the success rate. Implementing the process policy guidelines increased the number of cephalic presentations at delivery and decreased the rate of elective caesarean sections for breech presentation from 39% to 27% (p = 0.03). The number needed to treat to prevent 1 elective caesarean section by ECV according to the process policy guidelines was 8. After implementation of the process policy guidelines, the success rate of ECV increased considerably. The rate of elective caesarean section for breech presentation declined. These findings are in favour of establishing specialized ECV centres in the Netherlands.

  17. Septic Thrombophlebitis of the Cephalic Vein Caused by a Peripherally Inserted Venous Catheter

    Directory of Open Access Journals (Sweden)

    M Mirmohammadsadeghi

    2005-07-01

    Full Text Available Septic thrombophlebitis of a vein is a rare but life-threatening complication of an intravascular (IV catheter placed percutaneously in the veins. Most published clinical experiences with IV catheters, mainly in the outpatient settings, have reported very low rates of catheter-related bloodstream infection compared to rates with central venous catheters placed in a subclavian or internal jugular vein. Most of the complications reported with IV catheters have been non-infectious, particularly sterile phlebitis or thrombosis. We report a case of cephalic vein suppurative thrombophlebitis from an intravascular catheter and offer guidelines for diagnosis and management of this complication. Key words: Septic thrombophlebitis, Intravascular catheter, Suppurative thrombophlebitis

  18. Effect of regional anesthesia on the success rate of external cephalic version: a systematic review and meta-analysis.

    Science.gov (United States)

    Goetzinger, Katherine R; Harper, Lorie M; Tuuli, Methodius G; Macones, George A; Colditz, Graham A

    2011-11-01

    To estimate whether the use of regional anesthesia is associated with increased success of external cephalic version. We searched MEDLINE, EMBASE, the Cochrane Library, and clinical trial registries. Electronic databases were searched from 1966 through April 2011 for published, randomized controlled trials in the English language comparing regional anesthesia with no regional anesthesia for external cephalic version. The primary outcome was external cephalic version success. Secondary outcomes included cesarean delivery, maternal discomfort, and adverse events. Pooled risk ratios (relative risk) were calculated using a random-effects model. Heterogeneity was assessed using the Cochran's Q statistic and quantified using the I Z method. Six randomized controlled trials met criteria for study inclusion. Regional anesthesia was associated with a higher external cephalic version success rate compared with intravenous or no analgesia (59.7% compared with 37.6%; pooled relative risk 1.58; 95% confidence interval [CI] 1.29-1.93). This significant association persisted when the data were stratified by type of regional anesthesia (spinal compared with epidural). The number needed to treat with regional anesthesia to achieve one additional successful external cephalic version was five. There was no evidence of statistical heterogeneity (P=.32, I Z=14.9%) or publication bias (Harbord test P=.78). There was no statistically significant difference in the risk of cesarean delivery comparing regional anesthesia with intravenous or no analgesia (48.4% compared with 59.3%; pooled relative risk 0.80; 95% CI 0.55-1.17). Adverse events were rare and not significantly different between the two groups. Regional anesthesia is associated with a higher success rate of external cephalic version.

  19. Self-taught axillary vein access without venography for pacemaker implantation: prospective randomized comparison with the cephalic vein access.

    Science.gov (United States)

    Squara, Fabien; Tomi, Julien; Scarlatti, Didier; Theodore, Guillaume; Moceri, Pamela; Ferrari, Emile

    2017-12-01

    Axillary vein access for pacemaker implantation is uncommon in many centres because of the lack of training in this technique. We assessed whether the introduction of the axillary vein technique was safe and efficient as compared with cephalic vein access, in a centre where no operators had any previous experience in axillary vein puncture. Patients undergoing pacemaker implantation were randomized to axillary or cephalic vein access. All three operators had no experience nor training in axillary vein puncture, and self-learned the technique by reading a published review. Axillary vein puncture was fluoroscopy-guided without contrast venography. Cephalic access was performed by dissection of delto-pectoral groove. Venous access success, venous access duration (from skin incision to guidewire or lead in superior vena cava), procedure duration, X-ray exposure, and peri-procedural (1 month) complications were recorded. results We randomized 74 consecutive patients to axillary (n = 37) or cephalic vein access (n = 37). Axillary vein was successfully accessed in 30/37 (81.1%) patients vs. 28/37 (75.7%) of cephalic veins (P = 0.57). Venous access time was shorter in axillary group than in cephalic group [5.7 (4.4-8.3) vs. 12.2 (10.5-14.8) min, P < 0.001], as well as procedure duration [34.8 (30.6-38.4) vs. 42.0 (39.1-46.6) min, P = 0.043]. X-ray exposure and peri-procedural overall complications were comparable in both groups. Axillary puncture was safe and faster than cephalic access even for the five first procedures performed by each operator. Self-taught axillary vein puncture for pacemaker implantation seems immediately safe and faster than cephalic vein access, when performed by electrophysiologists trained to pacemaker implantation but not to axillary vein puncture. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For Permissions, please email: journals.permissions@oup.com.

  20. Neutral Sterols of Cephalic Glands of Stingless Bees and Their Correlation with Sterols from Pollen

    Directory of Open Access Journals (Sweden)

    Maria Juliana Ferreira-Caliman

    2012-01-01

    de novo and, thus, all phytophagous insects depend on an exogenous source of sterols for growth, development, and reproduction. The sterol requirements of social bees are not fully known due to the fact that there is no well-defined diet available throughout the year with regard to floral resources. Our study aimed to characterize the sterols present in pollen stored in Melipona marginata and Melipona scutellaris colonies, as well as evaluating their presence in the mandibular, hypopharyngeal, and cephalic salivary gland secretions. We analyzed the chemical composition of pollen stored in the colonies and the composition of the cephalic glands of workers in three adult functional phases (newly emerged, nurses, and foragers by gas chromatography and mass spectrometry. The results showed that the pollen analyzed contained campesterol, stigmasterol, sitosterol, isofucosterol, lanosterol, and small amounts of cholesterol. The glands showed the same compounds found in the pollen analyzed, except lanosterol that was not found in M. scutellaris glands. Surprisingly, cholesterol was found in some glands with relative ratios greater than those found in pollen.

  1. Implementation of client versus care-provider strategies to improve external cephalic version rates: a cluster randomized controlled trial

    NARCIS (Netherlands)

    Vlemmix, Floortje; Rosman, Ageeth N.; Rijnders, Marlies E.; Beuckens, Antje; Opmeer, Brent C.; Mol, Ben W. J.; Kok, Marjolein; Fleuren, Margot A. H.

    2015-01-01

    To determine the effectiveness of a client or care-provider strategy to improve the implementation of external cephalic version. Cluster randomized controlled trial. Twenty-five clusters; hospitals and their referring midwifery practices randomly selected in the Netherlands. Singleton breech

  2. Risk of developmental dysplasia of the hip in breech presentation: the effect of successful external cephalic version

    NARCIS (Netherlands)

    Lambeek, A. F.; de Hundt, M.; Vlemmix, F.; Akerboom, B. M. C.; Bais, J. M. J.; Papatsonis, D. N. M.; Mol, B. W. J.; Kok, M. [=Marjolein

    2013-01-01

    To evaluate the effect of successful external cephalic version on the incidence of developmental dysplasia of the hip (DDH) requiring treatment in singleton breech presentation at term. Observational cohort study. Three large teaching hospitals in the Netherlands. Women with a singleton breech

  3. Implementation of client versus care-provider strategies to improve external cephalic version rates: a cluster randomized controlled trial

    NARCIS (Netherlands)

    Vlemmix, F.; Rosman, A.N.; Rijnders, M.E.; Beuckens, A.; Opmeer, B.C.; Mol, B.W.J.; Kok, M.; Fleuren, M.A.H.

    2015-01-01

    Onjective: To determine the effectiveness of a client or care-provider strategy to improve the implementation of external cephalic version. Design: Cluster randomized controlled trial.Setting: Twenty-five clusters; hospitals and their referring midwifery practices randomly selected in the

  4. Radiotherapy of the cephalic segment in patients with advanced neuroblastoma; Radioterapia do segmento cefalico em pacientes portadores de neuroblastoma avancado

    Energy Technology Data Exchange (ETDEWEB)

    Weltman, Eduardo

    1995-07-01

    Although the treatment results have significantly improved for several pediatric malignant neoplasms, particularly Wilms's tumor, lymphomas and leukemia, in the last decade, the prognosis of the INSS, stage 4 neuroblastoma over one year one old patients remains poor. Even for the more advanced centers, using the more aggressive treatment schedules, such as bone marrow transplantation, the probability of a 2 year progression free interval varies from 6 to 50% and at 3 to 6 years, from 13 to 54%. Thereby, at least, 46 to 94% of these patients are expected to die due to the merciless neoplasm progression. The hypothesis here to be tested is regarding the impact of the cephalic irradiation on the outcome of stage 4 patients with skull metastasis at diagnosis. The end point was to establish, under the NEURO-III-85 protocol chemotherapy schedule, the possible benefit of this radiotherapy in preventing the cephalic recurrence, and its reflex on these patients total and diseases free survival. These results disclosed that the cephalic segment irradiation may prevent recurrences at this site. Unfortunately, the decrease in the cranial recurrence frequency did not affect either the disease free interval, or the total survival. The conclusion was that cephalic irradiation have the potential of avoiding these recurrences, without modifying the final outcome. This modality of radiotherapy must be reevaluated under more effective systemic treatments. (author)

  5. Amnioinfusion for women with a singleton breech presentation and a previous failed external cephalic version: a randomized controlled trial.

    Science.gov (United States)

    Diguisto, Caroline; Winer, Norbert; Descriaud, Celine; Tavernier, Elsa; Weymuller, Victoire; Giraudeau, Bruno; Perrotin, Franck

    2018-04-01

    Our trial aimed to assess the effectiveness of amnioinfusion for a second attempt at external cephalic version (ECV). This open randomized controlled trial was planned with a sequential design. Women at a term ≥36 weeks of gestation with a singleton fetus in breech presentation and a first unsuccessful ECV were recruited in two level-3 maternity units. They were randomly allocated to transabdominal amnioinfusion with a 500-mL saline solution under ultrasound surveillance or no amnioinfusion before the second ECV attempt. Trained senior obstetricians performed all procedures. The primary outcome was the cephalic presentation rate at delivery. Analyses were conducted according to intention to treat (NCT00465712). Recruitment difficulties led to stopping the trial after a 57-month period, 119 women were randomized: 59 allocated to amnioinfusion + ECV and 60 to ECV only. Data were analyzed without applying the sequential feature of the design. The rate of cephalic presentation at delivery did not differ significantly according to whether the second version attempt was or was not preceded by amnioinfusion (20 versus 12%, p = .20). Premature rupture of the membranes occurred for 15% of the women in the amnioinfusion group. Amnioinfusion before a second attempt to external version does not significantly increase the rate of cephalic presentation at delivery.

  6. Automatic Assessment of Global Craniofacial Differences between Crouzon mice and Wild-type mice in terms of the Cephalic Index

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur; Oubel, Estanislao; Frangi, Alejandro F.

    2006-01-01

    of landmark matching is limited using only affine transformations, the errors were considered acceptable. The automatic estimation of the cephalic index was in full agreement with the gold standard measurements. Discriminant analysis of the three scaling parameters resulted in a good classification...

  7. Radiotherapy of the cephalic segment in patients with advanced neuroblastoma; Radioterapia do segmento cefalico em pacientes portadores de neuroblastoma avancado

    Energy Technology Data Exchange (ETDEWEB)

    Weltman, Eduardo

    1995-07-01

    Although the treatment results have significantly improved for several pediatric malignant neoplasms, particularly Wilms's tumor, lymphomas and leukemia, in the last decade, the prognosis of the INSS, stage 4 neuroblastoma over one year one old patients remains poor. Even for the more advanced centers, using the more aggressive treatment schedules, such as bone marrow transplantation, the probability of a 2 year progression free interval varies from 6 to 50% and at 3 to 6 years, from 13 to 54%. Thereby, at least, 46 to 94% of these patients are expected to die due to the merciless neoplasm progression. The hypothesis here to be tested is regarding the impact of the cephalic irradiation on the outcome of stage 4 patients with skull metastasis at diagnosis. The end point was to establish, under the NEURO-III-85 protocol chemotherapy schedule, the possible benefit of this radiotherapy in preventing the cephalic recurrence, and its reflex on these patients total and diseases free survival. These results disclosed that the cephalic segment irradiation may prevent recurrences at this site. Unfortunately, the decrease in the cranial recurrence frequency did not affect either the disease free interval, or the total survival. The conclusion was that cephalic irradiation have the potential of avoiding these recurrences, without modifying the final outcome. This modality of radiotherapy must be reevaluated under more effective systemic treatments. (author)

  8. Tocolysis for repeat external cephalic version in breech presentation at term: a randomised, double-blinded, placebo-controlled trial.

    Science.gov (United States)

    Impey, Lawrence; Pandit, Meghana

    2005-05-01

    External cephalic version (ECV) reduces the incidence of breech presentation at term and caesarean section for non-cephalic births. Tocolytics may improve success rates, but are time consuming, may cause side effects and have not been proven to alter caesarean section rates. The aim of this trial was to determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. To determine whether tocolysis should be used if ECV is being re-attempted after a failed attempt. Randomised, double-blinded, placebo-controlled trial. UK teaching hospital. One hundred and twenty-four women with a breech presentation at term who had undergone an unsuccessful attempt at ECV. Relative risks with 95% confidence intervals for categorical variables and a t test for continuous variables. Analysis was by intention to treat. Incidence of cephalic presentation at delivery. Secondary outcomes were caesarean section and measures of neonatal and maternal morbidity. The use of tocolysis for a repeat attempt at ECV significantly increases the incidence of cephalic presentation at delivery (RR 3.21; 95% CI 1.23-8.39) and reduces the incidence of caesarean section (RR 0.33; 95% CI 0.14-0.80). The effects were most marked in multiparous women (RR for cephalic presentation at delivery 9.38; 95% CI 1.64-53.62). Maternal and neonatal morbidity remain unchanged. The use of tocolysis increases the success rate of repeat ECV and reduces the incidence of caesarean section. A policy of only using tocolysis where an initial attempt has failed leads to a relatively high success rate with minimum usage of tocolysis.

  9. Cephalic Disorders

    Science.gov (United States)

    ... destructive lesions, but are sometimes the result of abnormal development. The disorder can occur before or after birth. Porencephaly most ... decade of life. SCHIZENCEPHALY is a rare developmental disorder characterized by abnormal slits, or clefts, in the cerebral hemispheres. Schizencephaly ...

  10. Cephalic Disorders

    Science.gov (United States)

    ... information sheet compiled by the National Institute of Neurological Disorders and Stroke (NINDS). Patient Organizations Birth Defect Research for Children, Inc. 976 Lake Baldwin Lane Suite 104 Orlando ...

  11. Multiple regression analysis of anthropometric measurements influencing the cephalic index of male Japanese university students.

    Science.gov (United States)

    Hossain, Md Golam; Saw, Aik; Alam, Rashidul; Ohtsuki, Fumio; Kamarul, Tunku

    2013-09-01

    Cephalic index (CI), the ratio of head breadth to head length, is widely used to categorise human populations. The aim of this study was to access the impact of anthropometric measurements on the CI of male Japanese university students. This study included 1,215 male university students from Tokyo and Kyoto, selected using convenient sampling. Multiple regression analysis was used to determine the effect of anthropometric measurements on CI. The variance inflation factor (VIF) showed no evidence of a multicollinearity problem among independent variables. The coefficients of the regression line demonstrated a significant positive relationship between CI and minimum frontal breadth (p regression analysis showed a greater likelihood for minimum frontal breadth (p regression analysis revealed bizygomatic breadth, head circumference, minimum frontal breadth, head height and morphological facial height to be the best predictor craniofacial measurements with respect to CI. The results suggest that most of the variables considered in this study appear to influence the CI of adult male Japanese students.

  12. Labor induction just after external cephalic version with epidural analgesia at term.

    Science.gov (United States)

    Cuerva, Marcos J; Piñel, Carlos S; Caceres, Javier; Espinosa, Jose A

    2017-06-01

    To analyze the benefits of external cephalic version (ECV) with epidural analgesia at term and labor induction just after the procedure. This is a retrospective observational study with patients who did not want trying a breech vaginal delivery and decided trying an ECV with epidural analgesia at term and wanted labor induction or cesarean section after the procedure. We present the results of 40 ECV with epidural analgesia at term and labor induction or cesarean section just after the ECV. ECV succeeded in 26 out of 40 (65%) patients. Among the 26 successful ECV, 6 delivered by cesarean (23.1%). 20 patients delivered vaginally (76.9%; 50% of all patients). Considering that a high number of cesarean deliveries can be avoided, induction of labor after ECV with epidural analgesia at term can be considered after being discussed in selected patient. Copyright © 2017. Published by Elsevier B.V.

  13. Coming out ahead: the cost effectiveness of external cephalic version using spinal anesthesia

    Science.gov (United States)

    2014-01-01

    Breech presentation is encountered in 3 to 4% of term pregnancies and has been a significant driver of the increased rate of cesarean deliveries over the last 4 decades. External cephalic version (ECV) is recommended at term by most professional organizations in an effort to reduce the prospect of cesarean deliveries. The authors propose the use of regional anesthesia to increase efficacy and reduce cost in the care of patients who undergo ECV in an effort to convert a breech presentation to a vertex counterpart. Despite emerging evidence of the advantages, obstacles to more comprehensive implementation of this approach continue to exist, which include patient acceptance, provider experience, and safety concerns. The addition of tocolytics and use of regional anesthesia for secondary ECV efforts have also been considered as options to increase success and reduce cost. This is a commentary on http://www.ijhpr.org/content/3/1/5. PMID:24565024

  14. External cephalic version for breech presentation at term. A prospective interventional study.

    Science.gov (United States)

    Al-Jwadi, Saja A; Al-Ibrahim, Baraa L Humo

    2014-08-01

    To evaluate the external cephalic version (ECV) procedure for the management of at term breech presenting fetuses. In this prospective, interventional study, 90 patients with uncomplicated breech presentations at or after 37 weeks' gestation were considered for ECV. This was performed in Al-Batool Teaching Hospital, Mosul, Iraq, between January 2011 and March 2012. The main outcome measure was assessed as the success rate of ECV attempt and the rate of cesarean section following a successful procedure. Parity, type of breech, placental location, and birth weight were evaluated as predictors of success. Also, any fetal or maternal complications during the procedure were evaluated. Data were analyzed by x2 test. Statistical significance was determined at a level of pbreech. There were no serious fetal or maternal complications associated with the attempt. With appropriate selection of patients, ECV is highly successful and is a safer alternative to vaginal breech delivery or cesarean delivery.

  15. Maternal thyroid function and the outcome of external cephalic version: a prospective cohort study

    Science.gov (United States)

    2011-01-01

    Background To investigate the relation between maternal thyroid function and the outcome of external cephalic version (ECV) in breech presentation. Methods Prospective cohort study in 141 women (≥ 35 weeks gestation) with a singleton fetus in breech. Blood samples for assessing thyroid function were taken prior to ECV. Main outcome measure was the relation between maternal thyroid function and ECV outcome indicated by post ECV ultrasound. Results ECV success rate was 77/141 (55%), 41/48 (85%) in multipara and 36/93 (39%) in primipara. Women with a failed ECV attempt had significantly higher TSH concentrations than women with a successful ECV (p breech (OR: 0.30, 95% CI: 0.10-0.93) and placenta anterior (OR: 0.31, 95% CI: 0.11-0.85) were independently related to ECV success. Conclusions Higher TSH levels increase the risk of ECV failure. Trial registration number ClinicalTrials.gov: NCT00516555 PMID:21269431

  16. Maternal thyroid function and the outcome of external cephalic version: a prospective cohort study

    Directory of Open Access Journals (Sweden)

    van der Donk Riet W

    2011-01-01

    Full Text Available Abstract Background To investigate the relation between maternal thyroid function and the outcome of external cephalic version (ECV in breech presentation. Methods Prospective cohort study in 141 women (≥ 35 weeks gestation with a singleton fetus in breech. Blood samples for assessing thyroid function were taken prior to ECV. Main outcome measure was the relation between maternal thyroid function and ECV outcome indicated by post ECV ultrasound. Results ECV success rate was 77/141 (55%, 41/48 (85% in multipara and 36/93 (39% in primipara. Women with a failed ECV attempt had significantly higher TSH concentrations than women with a successful ECV (p Conclusions Higher TSH levels increase the risk of ECV failure. Trial registration number ClinicalTrials.gov: NCT00516555

  17. Diurnal change in gonadotropic activity in cephalic and caudal lobes of anterior pituitary in capons

    International Nuclear Information System (INIS)

    Kamiyoshi, Michiharu; Yoshihara, Masato; Tanaka, Katuhide

    1977-01-01

    Two groups of male white leghorn chickens were raised under two light regimens after hatch, 14 hr (0500 - 1900 hours) and 8 hr (0500 - 1300 hours) lighting per day, respectively. Both groups were caponized at 4 weeks of the age. At 10 weeks of the age, the anterior pituitaries were excised at different times during 24 hr period, and the gonadotropic activities of the cephalic and caudal lobes of anterior pituitary were measured by the bioassay of 32 D-uptake in chick test. In the 14 hr lighting per day group, peak gonadotropic activity was observed at 1100 hour (6 hr of lighting) in both lobes, but in the 8 hr lighting per day group, no peak was observed. The diurnal change of pituitary gonadotropic activity may be related to the photoperiod. (Mori, K.)

  18. Absorbed doses received by infants subjected to panoramic dental and cephalic radiographs

    International Nuclear Information System (INIS)

    Carrizales, L.; Carreno, S.

    1998-01-01

    The IAEA Report No. 115 recommends that each country or region can establish levels of absorbed doses for each radiographic technique employed in diagnostic. assuming the extended and expensive of this purpose, we have been to begin in a first step with the dentistry area, in order to estimate the dose levels received at crystalline and thyroid level in infants that go to an important public institution in our country to realize panoramic and cephalic radiographs. This work will serve to justify and impel a quality assurance program in Venezuela on the dentistry area which includes aspects such as training for the medical lap referring the justification of the radiological practice, optimization of X-ray units to produce an adequate image quality that delivers to patient an absorbed dose as much lower as reasonably it can be reached without diagnostic detriment. (Author)

  19. Cephalic phase secretion of insulin and other enteropancreatic hormones in humans

    DEFF Research Database (Denmark)

    Veedfald, Simon; Plamboeck, Astrid; Deacon, Carolyn F

    2016-01-01

    Enteropancreatic hormone secretion is thought to include a cephalic phase, but the evidence in humans is ambiguous. We studied vagally induced gut hormone responses with and without muscarinic blockade in 10 glucose-clamped healthy men (age: 24.5 ± 0.6 yr, means ± SE; body mass index: 24.0 ± 0.5 kg...... and abolished the MSF response. Neither insulin, C-peptide, glucose-dependent insulinotropic polypeptide (GIP), nor glucagon-like peptide-1 (GLP-1) levels changed in response to MSF or atropine. Glucagon and ghrelin levels were markedly attenuated by atropine prior to and during the clamp: at t = 105 min...... and 3.7 ± 21 pg/ml (means ± SE), P phase response was absent for insulin, glucagon, GLP-1, GIP, and ghrelin....

  20. Identification of oxygen containing volatiles in cephalic secretions of workers of Brazilian stingless bees

    Directory of Open Access Journals (Sweden)

    Francke Wittko

    2000-01-01

    Full Text Available The volatile constituents of cephalic secrections of 11 Brazilian social stingless bee species of the Tetragonisca - Tetragona line have been analysed. By gas chromatography/mass spectrometry 145 compounds could be identified which include 72 esters, 22 alcohols, 16 carboxylic acids, 13 terpenoids, 8 aldehydes, 7 ketones, 4 aromatic compounds, 2 lactones and 1 dihydropyran. Structural relations, origin, and distribution of these compounds are discussed. With respect to qualitative and quantitative composition, each species shows a specific odour pattern which is made up by less specific components. To a certain extent, closely related species show some similarities in the odour bouquets. The mass spectrometric fragmentation patterns of typical wax type esters and DMDS derivatives of unsaturated esters are discussed in detail.

  1. A randomized trial of remifentanil for analgesia in external cephalic version for breech presentation.

    Science.gov (United States)

    Liu, Xiaohua; Xue, Aiqin

    2016-12-01

    Although external cephalic version (ECV) can be effective for correcting the fetus in a cephalic presentation, it may be painful for the mother. This study aimed to evaluate the efficacy and safety of remifentanil for pain relief during ECV in China. In all, 152 Chinese parturients with singleton breech presentation were randomly divided into 2 groups, each with 76 patients. All 152 patients were assigned to receive either remifentanil (infused at 0.1 μg/kg/min and demand boluses of 0.1 μg/kg) or saline placebo. The study was performed between January 2012 and December 2015. Outcome measurements included the Numerical Rating Pain Scale score (0-10) after ECV, success rate for ECV, and maternal satisfaction after ECV. Adverse events were also evaluated. The study was completed by 146 patients. Remifentanil showed greater efficacy than placebo in decreasing the pain score immediately after ECV (remifentanil 4.6 ± 2.6 vs placebo 6.5 ± 2.7; P < 0.001). The success rate for ECV showed a significant difference between the 2 groups (remifentanil 56.5% vs placebo 39.5%; P = 0.04). Maternal satisfaction also showed a significant difference between the 2 groups (remifentanil 9.6 ± 1.4 vs placebo 6.4 ± 3.7; P < 0.001). However, the adverse events profiles were similar between both groups. The results of this study demonstrate that remifentanil is an effective intervention for reducing pain, achieving successful ECV, and increasing maternal satisfaction during ECV, and is generally well-tolerated without additional adverse effects.

  2. Maternal outcomes of term breech presentation delivery: impact of successful external cephalic version in a nationwide sample of delivery admissions in the United States.

    Science.gov (United States)

    Weiniger, Carolyn F; Lyell, Deirdre J; Tsen, Lawrence C; Butwick, Alexander J; Shachar, BatZion; Callaghan, William M; Creanga, Andreea A; Bateman, Brian T

    2016-07-08

    We aimed to define the frequency and predictors of successful external cephalic version in a nationally-representative cohort of women with breech presentations and to compare maternal outcomes associated with successful external cephalic version versus persistent breech presentation. Using the Nationwide Inpatient Sample, a United States healthcare utilization database, we identified delivery admissions between 1998 and 2011 for women who had successful external cephalic version or persistent breech presentation (including unsuccessful or no external cephalic version attempt) at term. Multivariable logistic regression identified patient and hospital-level factors associated with successful external cephalic version. Maternal outcomes were compared between women who had successful external cephalic version versus persistent breech. Our study cohort comprised 1,079,576 delivery admissions with breech presentation; 56,409 (5.2 %) women underwent successful external cephalic version and 1,023,167 (94.8 %) women had persistent breech presentation at the time of delivery. The rate of cesarean delivery was lower among women who had successful external cephalic version compared to those with persistent breech (20.2 % vs. 94.9 %; p external cephalic version were also less likely to experience several measures of significant maternal morbidity including endometritis (adjusted Odds Ratio (aOR) = 0.36, 95 % Confidence Interval (CI) 0.24-0.52), sepsis (aOR = 0.35, 95 % CI 0.24-0.51) and length of stay > 7 days (aOR = 0.53, 95 % CI 0.40-0.70), but had a higher risk of chorioamnionitis (aOR = 1.83, 95 % CI 1.54-2.17). Overall a low proportion of women with breech presentation undergo successful external cephalic version, and it is associated with significant reduction in the frequency of cesarean delivery and a number of measures of maternal morbidity. Increased external cephalic version use may be an important approach to mitigate the high rate of

  3. Finding the breech: Influence of breech presentation on mode of delivery based on timing of diagnosis, attempt at external cephalic version, and provider success with version.

    Science.gov (United States)

    Andrews, Suzanne; Leeman, Lawrence; Yonke, Nicole

    2017-09-01

    Breech presentation affects 3-4% of pregnancies at term and malpresentation is the primary indication for 10-15% of cesarean deliveries. External cephalic version is an effective intervention that can decrease the need for cesarean delivery; however, timely identification of breech presentation is required. We hypothesized that women with a fetus in a breech presentation that is diagnosed after 38 weeks' estimated gestational age have a decreased likelihood of external cephalic version attempted and an increased likelihood of cesarean delivery. This was a retrospective cohort study. A chart review was performed for 251 women with breech presentation at term presenting to our tertiary referral university hospital for external cephalic version, cesarean for breech presentation, or vaginal breech delivery. Vaginal delivery was significantly more likely (31.1% vs 12.5%; Pexternal cephalic version was offered, and subsequently attempted in a greater proportion of women diagnosed before 38 weeks. External cephalic version was more successful when performed by physicians with greater procedural volume during the 3.5 year period of the study (59.1% for providers performing at least 10 procedures vs 31.3% if performing fewer than 10 procedures, Pexternal cephalic version. © 2017 Wiley Periodicals, Inc.

  4. [External cephalic version after 36th week of gestationAnalysis of women´s perspective].

    Science.gov (United States)

    Wágnerová, K; Hruban, L; Janků, P

    2017-01-01

    Evaluation of opinions and subjective feelings of patients who have undergone an external cephalic version of a fetus in breech presentation after the 36th week of pregnancy. Observational analytic cohort study. Department of Obstetrics and Gynecology, Masaryk University, University Hospital Brno. We collected opinions and subjective evaluation from pregnant women who underwent an attempt of external cephalic version at the department of Gynecology and Obstetrics, Masaryk University in Brno in the period from 1st January 2015 to 31st December 2016 through a questionnaire. The questionnaire contained a total of 10 dichotomous, sampling, enumeration and scale questions. Questions were focused on the source and type of information on external cephalic version, expectations of the patients, evaluation of pain and feelings during the procedure and the overall impression. We also evaluated the differences between answers from patients after a successful and an unsuccessful version. In reported period 205 pregnant women underwent an attempt of external cephalic version. Procedure was successful in 105 (51.2%) cases of which 81 (77.1%) subsequently gave birth vaginally, 24 (22.9%) delivered by caesarean section, 10 (9.5%) out of all patients delivered in other hospitals. The total number of fully completed questionnaires was 187 (after a successful version 98 and 89 after an unsuccessful version). The most common source of information about the procedure was given to the patients from their gynecologists (40.5%) and doctors at the ambulance in the hospital where the patients are sent before delivery by their gynecologists (27.9%). Most mothers received mostly positive information (70.5%) - increased likelihood of vaginal delivery, high success rate, low risk to mother and child. Attitude of the gynecologists on the external cephalic version was positive in 52.6% and they recommended it. 14.4% of the patients had no fear before the procedure, 61% patients were nervous and

  5. Implementation of client versus care-provider strategies to improve external cephalic version rates: a cluster randomized controlled trial.

    Science.gov (United States)

    Vlemmix, Floortje; Rosman, Ageeth N; Rijnders, Marlies E; Beuckens, Antje; Opmeer, Brent C; Mol, Ben W J; Kok, Marjolein; Fleuren, Margot A H

    2015-05-01

    To determine the effectiveness of a client or care-provider strategy to improve the implementation of external cephalic version. Cluster randomized controlled trial. Twenty-five clusters; hospitals and their referring midwifery practices randomly selected in the Netherlands. Singleton breech presentation from 32 weeks of gestation onwards. We randomized clusters to a client strategy (written information leaflets and decision aid), a care-provider strategy (1-day counseling course focused on knowledge and counseling skills), a combined client and care-provider strategy and care-as-usual strategy. We performed an intention-to-treat analysis. Rate of external cephalic version in various strategies. Secondary outcomes were the percentage of women counseled and opting for a version attempt. The overall implementation rate of external cephalic version was 72% (1169 of 1613 eligible clients) with a range between clusters of 8-95%. Neither the client strategy (OR 0.8, 95% CI 0.4-1.5) nor the care-provider strategy (OR 1.2, 95% CI 0.6-2.3) showed significant improvements. Results were comparable when we limited the analysis to those women who were actually offered intervention (OR 0.6, 95% CI 0.3-1.4 and OR 2.0, 95% CI 0.7-4.5). Neither a client nor a care-provider strategy improved the external cephalic version implementation rate for breech presentation, neither with regard to the number of version attempts offered nor the number of women accepting the procedure. © 2015 Nordic Federation of Societies of Obstetrics and Gynecology.

  6. Exacting Responses: Lack of Endocrine Cephalic Phase Responses Upon Oro-Sensory Exposure

    Directory of Open Access Journals (Sweden)

    Marlou P. Lasschuijt

    2018-06-01

    Full Text Available Oro-sensory exposure (OSE to food plays an important role in the regulation of food intake. One proposed underlying mechanism is the occurrence of cephalic phase responses (CPRs. CPRs include the pre-digestive endocrine responses induced by food-related sensory input. Yet, whether OSE duration or sweetness intensity affects CPRs is unknown. The objective of this study was to determine the independent and interactive effects of oro-sensory duration (chewing and stimulation intensity (sweetness on endocrine CPRs and satiation. Eighteen males (22 ± 2 years, BMI 22 ± 2 kg/m2 participated in a 2 × 2 randomized study with a control condition. Each session participants performed modified sham feeding (MSF with one of the four gel-based model foods. During the control session no MSF was performed. Model foods differed in chewing duration (hard or soft texture and sweetness (low or high intensity. During each session, eight blood samples were collected up till 25 min after MSF onset. Subsequently, food intake from an ad libitum lunch was measured. No typical CPR was found for insulin, pancreatic polypeptide (PP, and ghrelin. However, the overall PP response was 1.1 times greater for the hard sweet MSF condition compared to control (p = 0.02. Overall ghrelin responses were 1.1 times greater for the hard model food compared to the soft model food conditions (p = 0.003. These differences in endocrine response were not associated with differences in food intake at the subsequent meal. Exploratory sub-analysis of the responsive insulin curves showed that after 2.5 min of MSF the hard texture model foods insulin concentrations were 1.2 greater compared to the soft texture. These findings indicate that texture hardness and sweetness increase the overall PP response and that MSF on hard texture increases the overall ghrelin response compared to soft texture model foods. However, MSF on model foods does not lead to a typical CPR

  7. The outcomes and risk factors of fetal bradycardia associated with external cephalic version.

    Science.gov (United States)

    Suyama, Fumio; Ogawa, Kohei; Tazaki, Yukiko; Miwa, Terumi; Taniguchi, Kosuke; Nakamura, Noriyuki; Tanaka, Satomi; Tanigaki, Shinji; Sago, Haruhiko

    2017-11-02

    The objective of this study is to assess the outcomes and risk factors of fetal bradycardia after external cephalic version (ECV). We performed a retrospective study of women who underwent ECV after 35 weeks of gestation in 2010-2016. We assessed the birth outcomes, including umbilical cord artery pH, according to the duration of fetal bradycardia and the risk factors for bradycardia. Among 390 cases, 189 (48.5%) cases showed fetal bradycardia during or immediately after ECV. The duration of fetal bradycardia was 10 min occurred in three cases; emergency cesarean section was performed in each case, with delivery after 12-4 min of bradycardia. Two of three cases showed low Apgar scores at 5 min, with an umbilical cord arterial pH of 10 min after ECV was a risk factor for asphyxia. Thus, delivery should be completed within 10 min after bradycardia. A low maternal BMI and a prolonged ECV procedure were risk factors for bradycardia after ECV.

  8. [Predictors of success of external cephalic version: Bi-center study].

    Science.gov (United States)

    Dochez, V; Delbos, L; Esbelin, J; Volteau, C; Winer, N; Sentilhes, L

    2016-05-01

    In the literature, success rate of external cephalic version (ECV) is 39 to 65%. This study aims to identify potential predictors of a successful ECV. Retrospective bi-center study performed from January 2011 through December 2012 at Angers University Hospital and Nantes University Hospital from January 2011 through December 2011. Were identified the demographic and ultrasonography characteristics of patients and the data of the process. One hundred and seventy-eight patients were included, 88 in Angers and 90 in Nantes; 16.3% of ECV were successful. Multiparity (OR 28.45; P<0.01) and transverse position (OR 0.63; P<0.01) are the two significant predictors. There is no significant difference found for center, operator, position of the placenta, amniotic fluid or presence of a uterine scar. The success rate in our two French university centers is much lower than that reported in the literature. Parity and transverse position are the only 2 significant predictors of ECV success. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  9. The efficacy and safety of external cephalic version after a previous caesarean delivery.

    Science.gov (United States)

    Weill, Yishay; Pollack, Raphael N

    2017-06-01

    External cephalic version (ECV) in the presence of a uterine scar is still considered a relative contraindication despite encouraging studies of the efficacy and safety of this procedure. We present our experience with this patient population, which is the largest cohort published to date. To evaluate the efficacy and safety of ECV in the setting of a prior caesarean delivery. A total of 158 patients with a fetus presenting as breech, who had an unscarred uterus, had an ECV performed. Similarly, 158 patients with a fetus presenting as breech, and who had undergone a prior caesarean delivery also underwent an ECV. Outcomes were compared. ECV was successfully performed in 136/158 (86.1%) patients in the control group. Of these patients, 6/136 (4.4%) delivered by caesarean delivery. In the study group, 117/158 (74.1%) patients had a successful ECV performed. Of these patients, 12/117 (10.3%) delivered by caesarean delivery. There were no significant complications in either of the groups. ECV may be successfully performed in patients with a previous caesarean delivery. It is associated with a high success rate, and is not associated with an increase in complications. © 2016 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  10. Matched cohort study of external cephalic version in women with previous cesarean delivery.

    Science.gov (United States)

    Keepanasseril, Anish; Anand, Keerthana; Soundara Raghavan, Subrahmanian

    2017-07-01

    To evaluate the efficacy and safety of external cephalic version (ECV) among women with previous cesarean delivery. A retrospective study was conducted using data for women with previous cesarean delivery and breech presentation who underwent ECV at or after 36 weeks of pregnancy during 2011-2016. For every case, two multiparous women without previous cesarean delivery who underwent ECV and were matched for age and pregnancy duration were included. Characteristics and outcomes were compared between groups. ECV was successful for 32 (84.2%) of 38 women with previous cesarean delivery and 62 (81.6%) in the control group (P=0.728). Multivariate regression analysis confirmed that previous cesarean was not associated with ECV success (odds ratio 1.89, 95% confidence interval 0.19-18.47; P=0.244). Successful vaginal delivery after successful ECV was reported for 19 (59.4%) women in the previous cesarean delivery group and 52 (83.9%) in the control group (P<0.001). No ECV-associated complications occurred in women with previous cesarean delivery. To avoid a repeat cesarean delivery, ECV can be offered to women with breech presentation and previous cesarean delivery who are otherwise eligible for a trial of labor. © 2017 International Federation of Gynecology and Obstetrics.

  11. This baby is not for turning: Women's experiences of attempted external cephalic version.

    Science.gov (United States)

    Watts, N P; Petrovska, K; Bisits, A; Catling, C; Homer, C S E

    2016-08-26

    Existing studies regarding women's experiences surrounding an External Cephalic Version (ECV) report on women who have a persistent breech post ECV and give birth by caesarean section, or on women who had successful ECVs and plan for a vaginal birth. There is a paucity of understanding about the experience of women who attempt an ECV then plan a vaginal breech birth when their baby remains breech. The aim of this study was to examine women's experience of an ECV which resulted in a persistent breech presentation. A qualitative descriptive exploratory design was undertaken. In-depth semi-structured interviews were conducted and analysed thematically. Twenty two (n = 22) women who attempted an ECV and subsequently planned a vaginal breech birth participated. Twelve women had a vaginal breech birth (55 %) and 10 (45 %) gave birth by caesarean section. In relation to the ECV, there were five main themes identified: 'seeking an alternative', 'needing information', 'recounting the ECV experience', 'reacting to the unsuccessful ECV' and, 'reflecting on the value of an ECV'. ECV should form part of a range of options provided to women, rather than a default procedure for management of the term breech. For motivated women who fit the safe criteria for vaginal breech birth, not being subjected to a painful experience (ECV) may be optimal. Women should be supported to access services that support vaginal breech birth if this is their choice, and continuity of care should be standard practice.

  12. Implementation of external cephalic version in the Netherlands: a retrospective cohort study.

    Science.gov (United States)

    Vlemmix, Floortje; Rosman, Ageeth N; te Hoven, Susan; van de Berg, Suzanne; Fleuren, Margot A H; Rijnders, Marlies E; Beuckens, Antje; Opmeer, Brent C; Mol, Ben Willem J; Kok, Marjolein

    2014-12-01

    External cephalic version (ECV) reduces the rate of elective cesarean sections as a result of breech presentation. Several studies have shown that not all eligible women undergo an ECV attempt. The aim of this study was to evaluate the implementation of ECV in the Netherlands and to explain variation in implementation rates with hospital characteristics and individual factors. We invited 40 hospitals to participate in this retrospective cohort study. We reviewed hospital charts for all singleton breech deliveries from 36 weeks' gestation and onwards between January 2008 and December 2009. We documented whether an ECV attempt was performed, reasons for not performing an attempt, mode of delivery, and hospital characteristics. We included 4,770 women from 36 hospitals. ECV was performed in 2,443 women (62.2% of eligible women, range 8.2-83.6% in different hospitals). Implementation rates were higher in teaching hospitals, hospitals with special office hours for ECV, larger obstetric units, and hospitals located in larger cities. Suboptimal implementation was mainly caused by health care providers who did not offer ECV. ECV implementation rates vary widely among hospitals. Suboptimal implementation is mostly caused by the care provider not offering the treatment and secondly due to women not opting for the offered attempt. A prerequisite for designing a proper implementation strategy is a detailed understanding of the exact reasons for not offering and not opting for ECV. © 2014 Wiley Periodicals, Inc.

  13. Standards for midwife practitioners of external cephalic version: A Delphi study.

    Science.gov (United States)

    Walker, Shawn; Perilakalathil, Prasanth; Moore, Jenny; Gibbs, Claire L; Reavell, Karen; Crozier, Kenda

    2015-05-01

    expansion of advanced and specialist midwifery practitioner roles across professional boundaries requires an evidence-based framework to evaluate achievement and maintenance of competency. In order to develop the role of Breech Specialist Midwife to include the autonomous performance of external cephalic version within one hospital, guidance was required on standards of training and skill development, particularly in the use of ultrasound. a three-round Delphi survey was used to determine consensus among an expert panel, including highly experienced obstetric and midwife practitioners, as well as sonographers. The first round used mostly open-ended questions to gather data, from which statements were formed and returned to the panel for evaluation in subsequent rounds. standards for achieving and maintaining competence to perform ECV, and in the use of basic third trimester ultrasound as part of this practice, should be the same for midwives and doctors. The maintenance of proficiency requires regular practice. midwives can appropriately expand their sphere of practice to include ECV and basic third trimester ultrasound, according to internal guidelines, following the completion of a competency-based training programme roughly equivalent to those used to guide obstetric training. Ideally, ECV services should be offered in organised clinics where individual practitioners in either profession are able to perform approximately 30 or more ECVs per year in order to maintain an appropriate level of skill. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Systematic review of adverse outcomes of external cephalic version and persisting breech presentation at term.

    Science.gov (United States)

    Nassar, Natasha; Roberts, Christine L; Barratt, Alexandra; Bell, Jane C; Olive, Emily C; Peat, Brian

    2006-03-01

    The aim of this study was to determine the frequency of adverse maternal and fetal outcomes of both external cephalic version (ECV) and persisting breech presentation at term. We conducted a systematic review of the literature using Medline, Embase and All Evidence Based Medicine (EBM) Reviews databases. Data were extracted from studies that compared women who had an ECV from 36 weeks' gestation with a similar control group of women enrolled at the same gestational age, eligible for, but who did not have an ECV. Eleven studies with a total of 2503 women were included. Adverse outcomes related to ECV were rarely reported and in most studies there was no evidence that relevant outcomes were ascertained among similar women who did not have an ECV. There was no increased risk of antepartum fetal death associated with ECV, but numbers were small. There were no reported cases of uterine rupture, placental abruption, prelabour rupture of membranes or cord prolapse, but these outcomes were not examined among controls. Onset of labour within 24 h and nuchal cord was non-significantly higher among women who had an ECV compared with those with a persisting breech. Despite limited reporting and small numbers, the results of our review suggest that adverse maternal and fetal outcomes of both ECV and persisting breech presentation are rare. Only with improved reporting and collection of safety data on ECV and persisting breech presentation can we provide high-quality information to assist informed decision making by pregnant women with a breech presentation at term.

  15. Contraindications for external cephalic version in breech position at term: a systematic review.

    Science.gov (United States)

    Rosman, Ageeth N; Guijt, Aline; Vlemmix, Floortje; Rijnders, Marlies; Mol, Ben W J; Kok, Marjolein

    2013-02-01

    External cephalic version (ECV) is a safe and effective intervention that can prevent breech delivery, thus reducing the need for cesarean delivery. It is recommended in national guidelines. These guidelines also mention contraindications for ECV, and thereby restrict the application of ECV. We assessed whether the formulation of these contraindications in guidelines are based on empiric data. Systematic review. Pregnant women with a singleton breech presentation from 34 weeks. We searched the National Guideline Clearinghouse, the Cochrane Central Register of Controlled Trials, MEDLINE (1953-2009), EMBASE (1980-2009), TRIP database (until 2011), NHS (National Health Services, until 2011), Diseases database (until 2011) and NICE guidelines (until 2011) for existing guidelines on ECV and studied the reproducibility of the contraindications stated in the guidelines. Furthermore, we systematically reviewed the literature for contraindications and evidence on these contraindications. Contraindications of ECV. We found five guidelines mentioning 18 contraindications, varying from five to 13 per guideline. The contraindications were not reproducible between the guidelines with oligohydramnios as the only contraindication mentioned in all guidelines. The literature search yielded 60 studies reporting on 39 different contraindications, of which we could only assess evidence of six of them. The present study shows that there is no general consensus on the eligibility of patients for ECV. Therefore we propose to limit contraindications for ECV to clear empirical evidence or to those with a clear pathophysiological relevance. © 2012 The Authors Acta Obstetricia et Gynecologica Scandinavica© 2012 Nordic Federation of Societies of Obstetrics and Gynecology.

  16. Versión cefálica externa External cephalic version

    Directory of Open Access Journals (Sweden)

    John Jairo Zuleta Tobón

    1994-01-01

    Full Text Available Se revisa el tema controvertido de la versión cefálica externa que pretende corregir la presentación podálica y atender el parto por vía vaginal; se resumen los requisitos para la maniobra y sus aspectos técnicos así como los motivos para suspender el Intento de versión y para terminar el embarazo; se recalcan las contraindicaciones y las complicaciones. Se concluye que es necesario diseñar protocolos de Investigación para lograr más claridad respecto a este procedimiento en nuestro medio.

    A review is presented on the controversial subject of external cephalic version; this procedure has the purpose of attaining a vaginal delivery after correcting a breech presentation. Requirements and technical aspects are summarized; the reasons for discontinuing the attempt and for terminating pregnancy after It are included as well. Contraindications and complications are emphasized. It is concluded that research on the subject is required In order to gain clarity on the advisability of this version In the Colombian milieu.

  17. Cephalic salivary glands of two species of advanced eusocial bees (Hymenoptera: Apidae: morphology and secretion

    Directory of Open Access Journals (Sweden)

    Silvana B. Poiani

    2010-01-01

    Full Text Available Some adult eusocial bees have a pair of cephalic salivary glands (CSG in addition to the thoracic labial or salivary gland pairs. This paper deals with variations in morphological features and secretion production of the CSG of females and males of Apis mellifera Linnaeus, 1758 and Scaptotrigona postica Latreille, 1807. The following life stages were studied: newly emerged, nurse, and forager workers; newly emerged and egg-laying queens; and newly emerged and sexually mature males. The histological results showed that the CSG differs between the two species in the following features: while alveoli and duct cells are cuboidal in workers and queens of A. mellifera, they change from cuboidal to flat in S. postica as the workers age. The glands of newly emerged males and females of A. mellifera are similar. However, as males become sexually mature, glands degenerate and practically disappear. The secretion from the glands of females of both species is oleaginous and gradually accumulates in the lumen of the alveoli in the beginning of the adult phase. Consequently, forager workers and egg-laying queens exhibit more turgid alveoli than younger individuals. Sudan black and Nile's blue staining indicated that the CSG secretion consists of neutral lipids. The possible role of gland secretion is discussed taking in account tasks performed by the individuals in the particular phases studied.

  18. Cephalic Arch Stenosis in Autogenous Haemodialysis Fistulas: Treatment With the Viabahn Stent-Graft

    Energy Technology Data Exchange (ETDEWEB)

    Shawyer, Andrew, E-mail: andrew.shawyer@bartsandthelondon.nhs.uk [The Royal London Hospital, Radiology Department (United Kingdom); Fotiadis, Nicos I., E-mail: fotiadis.nicholas@gmail.com [Royal Marsden Hospital, Radiology Department, The Royal Marsden NHS Foundation Trust (United Kingdom); Namagondlu, Girish, E-mail: girish.namagondlu@bartsandthelondon.nhs.uk [The Royal London Hospital, Renal Medicine Department (United Kingdom); Iyer, Arun, E-mail: arun.iyer@bartsandthelondon.nhs.uk [The Royal London Hospital, Radiology Department (United Kingdom); Blunden, Mark, E-mail: mark.blunden@bartsandthelondon.nhs.uk; Raftery, Martin, E-mail: martin.raftery@bartsandthelondon.nhs.uk; Yaqoob, Magdi, E-mail: magdi.yaqoob@bartsandthelondon.nhs.uk [The Royal London Hospital, Renal Medicine Department (United Kingdom)

    2013-02-15

    Cephalic arch stenosis (CAS) is an important and common cause of dysfunction in autogenous haemodialysis fistulas that requires multiple reinterventions and aggressive surveillance. We evaluated the safety and efficacy of the Viabahn stent-graft for the management of CAS. Between April 2005 and October 2011, 11 consecutive patients [four men and seven women (mean age 56.7 years)] with CAS and dysfunctional fistulas were treated with insertion of 11 Viabahn stent-grafts. Six stent-grafts were inserted due to residual stenosis after angioplasty and five for fistuloplasty-induced rupture. No patient was lost to follow-up. The technical and clinical success rate was 100 %. Primary access patency rates were 81.8 % [95 % confidence interval (CI) 0.482-0.977] at 6 months and 72.7 % (95 % CI 0.390-0.939) at 12 months. Secondary access patency rates were 90.9 % at 6 months (95 % CI 0.587-0.997). There were no procedure-related complications. Mean follow-up was 543.8 days (range 156-2,282). The use of the Viabahn stent-graft in the management of CAS is technically feasible and, in this small series, showed patency rates that compare favorably with historical data of angioplasty and bare stents.

  19. Cephalic Arch Stenosis in Autogenous Haemodialysis Fistulas: Treatment With the Viabahn Stent-Graft

    International Nuclear Information System (INIS)

    Shawyer, Andrew; Fotiadis, Nicos I.; Namagondlu, Girish; Iyer, Arun; Blunden, Mark; Raftery, Martin; Yaqoob, Magdi

    2013-01-01

    Cephalic arch stenosis (CAS) is an important and common cause of dysfunction in autogenous haemodialysis fistulas that requires multiple reinterventions and aggressive surveillance. We evaluated the safety and efficacy of the Viabahn stent-graft for the management of CAS. Between April 2005 and October 2011, 11 consecutive patients [four men and seven women (mean age 56.7 years)] with CAS and dysfunctional fistulas were treated with insertion of 11 Viabahn stent-grafts. Six stent-grafts were inserted due to residual stenosis after angioplasty and five for fistuloplasty-induced rupture. No patient was lost to follow-up. The technical and clinical success rate was 100 %. Primary access patency rates were 81.8 % [95 % confidence interval (CI) 0.482–0.977] at 6 months and 72.7 % (95 % CI 0.390–0.939) at 12 months. Secondary access patency rates were 90.9 % at 6 months (95 % CI 0.587–0.997). There were no procedure-related complications. Mean follow-up was 543.8 days (range 156–2,282). The use of the Viabahn stent-graft in the management of CAS is technically feasible and, in this small series, showed patency rates that compare favorably with historical data of angioplasty and bare stents.

  20. Association of external cephalic version before term with late preterm birth.

    Science.gov (United States)

    Poole, Kristie L; McDonald, Sarah D; Griffith, Lauren E; Hutton, Eileen K

    2017-08-01

    While evidence suggests that beginning an external cephalic version (ECV) before term (34 0/7 to 36 6/7 weeks) compared with after term may be associated with an increase in late preterm birth (34 0/7 to 36 6/7 weeks), it remains unknown what might account for this risk. The objective of the present study is to further investigate the association between ECV before term and late preterm birth. Secondary analysis of data collected from the international, multicenter Early ECV trials. We evaluated the relation between ECV exposure and late preterm birth (34 0/7 to 36 6/7 weeks), as well as whether additional risk factors for preterm birth (such as maternal age, height, body mass index, parity, placental location, and perinatal mortality rate) moderated this relation. Generalized linear mixed methods were used to account for center effect and adjust for covariates. Among 1765 women with breech pregnancies and without a prior preterm birth, 749 (42.4%) received at least one ECV before term. Exposure to an ECV before term was not associated significantly independently with odds of preterm birth. However, placenta location moderated the association between early ECV exposure and late preterm birth. The odds of preterm birth in women who were exposed to an ECV before term and who also had an anterior placenta were doubled (OR 2.05; 95% CI 1.12-3.71; p = 0.02). In a large cohort of women without known risks for preterm birth, those with an anterior placenta who undergo an ECV before term constitute a subgroup at particular risk for late preterm birth. © 2017 Nordic Federation of Societies of Obstetrics and Gynecology.

  1. Evaluation of the learning curve for external cephalic version using cumulative sum analysis.

    Science.gov (United States)

    Kim, So Yun; Han, Jung Yeol; Chang, Eun Hye; Kwak, Dong Wook; Ahn, Hyun Kyung; Ryu, Hyun Mi; Kim, Moon Young

    2017-07-01

    We evaluated the learning curve for external cephalic version (ECV) using learning curve-cumulative sum (LC-CUSUM) analysis. This was a retrospective study involving 290 consecutive cases between October 2013 and March 2017. We evaluated the learning curve for ECV on nulli and over para 1 group using LC-CUSUM analysis on the assumption that 50% and 70% of ECV procedures succeeded by description a trend-line of quadratic function with reliable R 2 values. The overall success rate for ECV was 64.8% (188/290), while the success rate for nullipara and over para 1 groups was 56.2% (100/178) and 78.6% (88/112), respectively. 'H' value, that the actual failure rate does not differ from the acceptable failure rate, was -3.27 and -1.635 when considering ECV success rates of 50% and 70%, respectively. Consequently, in order to obtain a consistent 50% success rate, we would require 57 nullipara cases, and in order to obtain a consistent 70% success rate, we would require 130 nullipara cases. In contrast, 8 to 10 over para 1 cases would be required for an expected success rate of 50% and 70% on over para 1 group. Even a relatively inexperienced physician can experience success with multipara and after accumulating experience, they will manage nullipara cases. Further research is required for LC-CUSUM involving several practitioners instead of a single practitioner. This will lead to the gradual implementation of standard learning curve guidelines for ECV.

  2. Survey of external cephalic version for breech presentation and neuraxial blockade use.

    Science.gov (United States)

    Weiniger, Carolyn F; Sultan, Pervez; Dunn, Ashley; Carvalho, Brendan

    2016-11-01

    Neuraxial blockade may increase external cephalic version (ECV) success rates. This survey aimed to assess the frequency and characteristics of neuraxial blockade used to facilitate ECV. We surveyed Society for Obstetric Anesthesia and Perinatology members regarding ECV practice using a 15-item survey developed by 3 obstetric anesthesiologists and tested for face validity. The survey was e-mailed in January 2015 and again in February 2015 to the 1056 Society of Obstetric Anesthesiology and Perinatology members. We present descriptive statistics of responses. Our survey response rate was 322 of 1056 (30.5%). Neuraxial blockade was used for ECV always by 18 (5.6%), often by 52 (16.1%), sometimes by 98 (30.4%), rarely by 78 (24.2%), and never by 46 (14.3%) of respondents. An anesthetic sensory block target was selected by 141 (43.8%) respondents, and analgesic by 102 (31.7%) respondents. Epidural drug doses ranged widely, including sufentanil 5-25 μg; lidocaine 1% or 2% 10-20 mL, bupivacaine 0.0625% to 0.5% 6-15 mL, and ropivacaine 0.2% 20 mL. Intrathecal bupivacaine was used by 182 (56.5%) respondents; the most frequent doses were 2.5 mg used by 24 (7.5%), 7.5 mg used by 35 (10.9%), and 12 mg used by 30 (9.3%). Neuraxial blockade is not universally offered to facilitate ECV, and there is wide variability in neuraxial blockade techniques, in drugs and doses administered, and in the sensory blockade (anesthetic or analgesic) targeted. Future studies need to evaluate and remove barriers to allow for more widespread use of neuraxial blockade for pain relief and to optimize ECV success rates. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Predictors for a successful external cephalic version: a single centre experience.

    Science.gov (United States)

    Ebner, Florian; Friedl, Thomas W P; Leinert, Elena; Schramm, Amelie; Reister, Frank; Lato, Kristian; Janni, Wolfgang; DeGregorio, Nikolaus

    2016-04-01

    The external cephalic version (ECV) is one of the options patients presenting with a breech pregnancy should be offered. Various fetal, maternal and other predictors for a successful ECV have been published in the past. This is a retrospective multivariate analysis of our ECV patient database at the Department of Obstetrics and Gynaecology at the University Hospital Ulm. In an outpatient setting, patients with fetal breech position were routinely offered an ECV attempt after 36 weeks of gestation if the patient was willing to consent. Contraindications for ECV were placental abruption, placenta praevia, uterus malformations, regular contractions, premature rupture of membranes, and non-reassuring fetal heart rate patterns. From January 1st 2010 to July 31st 2013, 444 patients with a minimum of 36 weeks gestational age (i.e. >35 + 6 weeks) attended our clinic with a breech presentation. Of those 118 had an ECV attempt and an extended ultrasound examination within 21 days. In 33 patients the procedure was successful (success rate 28 %). A multivariate binary logistic regression analysis revealed that an increased Amniotic Fluid Index (AFI; p < 0.001), at least one prior vaginal delivery (p = 0.002) or a high estimated fetal weight (p = 0.045) were significant independent predictors for a successful ECV. In our series no delivery occurred within 48 h after the ECV. An ECV is a safe procedure. ECV should be offered as an option for the mother-to-be on the basis of an informed consent. Identified fetal and maternal factors can help to estimate the chances of success and in particular multi-parity and increased amniotic fluid seem to be associated with successful ECV.

  4. Effect of maternal intravenous fluid therapy on external cephalic version at term: a prospective cohort study.

    Science.gov (United States)

    Burgos, Jorge; Quintana, Eider; Cobos, Patricia; Osuna, Carmen; Centeno, María del Mar; Melchor, Juan Carlos

    2014-12-01

    We sought to analyze whether maternal intravenous fluid therapy prior to external cephalic version (ECV) increases the amount of amniotic fluid and the success rate of the procedure. This was a prospective single-center cohort study of 200 women with a consecutive cohort of 100 pregnant women with a breech presentation at term who were administered intravenous fluid therapy with 2 L of hypotonic saline before the version attempt, compared to a control cohort of 100 pregnant women not given hydration treatment. The mean increase in the amniotic fluid index (AFI) after intravenous maternal hydration was 3.75 ± 2.71 cm. The amount of fluid before hydration was the only variable found to be associated with increases in amniotic fluid levels, both in absolute and relative terms (odds ratio, -0.21; 95% confidence interval, -0.37 to -0.05 and odds ratio, -4.62; 95% confidence interval, -6.17 to -3.06; P < .01, respectively). We did not observe any severe complications secondary to the intravenous fluid therapy. The ECV success rate was 43% in the study group compared to 47% in the control group (P = .67). The success rate was significantly lower the larger the relative increase in the AFI, although no correlation was found in absolute terms (χ(2) for linear trend = 0.03 and 0.34, respectively). Maternal intravenous fluid therapy with 2 L of hypotonic saline prior to ECV is an effective and safe technique for increasing the AFI. However, its use in ECV does not increase the success rate of the procedure. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Uptake of external cephalic version for term breech presentation: an Australian population study, 2002-2012.

    Science.gov (United States)

    Bin, Yu Sun; Roberts, Christine L; Nicholl, Michael C; Ford, Jane B

    2017-07-26

    The safety, efficacy, and cost-effectiveness of external cephalic version (ECV) for term breech presentation has been demonstrated. Clinical guidelines recommend ECV for all eligible women, but the uptake of this procedure in the Australian healthcare setting is unknown. This study aimed to describe ECV uptake in New South Wales, the most populous state of Australia, during 2002 to 2012. Data from routine hospital and birth records were used to identify ECVs conducted at ≥36 weeks' gestation. Women with ECV were compared to women who were potentially eligible for but did not have ECV. Eligibility for ECV was based on clinical guidelines. For those with ECV, birth outcomes following successful and unsuccessful procedures were examined. In N = 32,321 singleton breech pregnancies, 10.5% had ECV, 22.3% were ineligible, and 67.2% were potentially eligible but did not undergo ECV. Compared to women who were eligible but who did not attempt ECV, those who had ECV were more likely to be older, multiparous, overseas-born, public patients at delivery, and to deliver in tertiary hospitals in urban areas (p < 0.01). Fewer women who underwent ECV smoked during pregnancy, fewer were morbidly obese, and fewer had a hypertensive disorder of pregnancy, compared to those who were eligible. Caesarean section occurred in 25.9% of successful compared to 95.6% of unsuccessful ECVs. Infant outcomes did not differ by ECV success. The majority of women with a breech presentation did not receive ECV. It is unclear whether this is attributable to issues with service provision or low acceptability among women. Policies to improve access to and information about ECV appear necessary to improve uptake among women with term breech presentation. Improved data collection around the diagnosis of breech presentation, ECV attempts, and outcomes may help to identify specific barriers to ECV uptake.

  6. Predictors of successful external cephalic version and assessment of success for vaginal delivery.

    Science.gov (United States)

    Salzer, Liat; Nagar, Ran; Melamed, Nir; Wiznitzer, Arnon; Peled, Yoav; Yogev, Yariv

    2015-01-01

    To identify predictors of successful external cephalic version (ECV) and to compare delivery outcome between women who had a successful ECV and women with spontaneous vertex presentation. A retrospective cohort study of all women who underwent ECV in a single tertiary medical center between 2007 and 2011. Delivery outcome was compared between women who underwent a trial of vaginal delivery following successful ECV with that of a control group in a 2:1 ratio. Multivariate analysis was used to identify predictors of successful ECV. Overall 287 were eligible for the study group. Of these 130 (45.3%) had a successful ECV. Polyhydramnios was the strongest factor associated with successful ECV (OR=3.1, 95%-CI 1.4-7.2), followed by transverse lie (versus breech presentation, OR=2.6, 95%-CI 1.2-6.7) and a posterior placenta (OR=1.7, 95%-CI 1.1-3.9), while nulliparity was associated with a lower likelihood of successful ECV (OR=0.4, 95%-CI 0.2-0.6). Women who had a successful ECV and underwent a trial of labor were more likely to deliver by operative vaginal delivery (OVD) (OR=1.8, 95%-CI 1.2-3.6), mainly due to a higher rate of prolonged 2nd, but were not at an increased risk for CS (OR=0.9, 95%-CI 0.4-2.4). Counselling to women prior to ECV should address the likelihood of success based on the predicting factors described above, as well as the increased risk for OVD in the case of successful ECV.

  7. Predictors of successful external cephalic version in an Australian maternity hospital.

    Science.gov (United States)

    Mowat, Alex; Gardener, Glenn

    2014-02-01

    There are minimal data involving predictors of success of external cephalic version (ECV) in an Australian healthcare setting. To determine the predictors of successful ECV as well as the success rate of ECV and the mode of, and presentation at, delivery for women undergoing ECV for breech presentation from 36-weeks gestation. A prospective review was carried out on all women who had undergone ECV from 36-weeks gestation at the Mater Mothers Hospital over an 8-year period from 2001 to 2008. Data were collected prospectively and were collated in conjunction with database review, chart review and telephonic patient interviews. A total of 355 women underwent ECV for breech presentation. The overall success rate was 66% (57% for nulliparous, 76% for multiparous). A woman who underwent ECV had a 46% chance of a vaginal birth. If the ECV was successful, she had a 70% chance of vaginal birth. From bivariate analysis, parity, amniotic fluid index (AFI) and estimated fetal weight (EFW) were determined to be possible predictors of success of ECV and were included in the logistic regression modelling. In the regression analysis, multiparity increased the odds of successful ECV by 2.18. For every one unit increase in AFI, the odds of successful ECV increased by 1.18. Multiparity and amniotic fluid volume as assessed by AFI were the significant predictors of immediate success of ECV. Conversely, lower AFI and nulliparity are factors that are likely to reduce the likelihood of successful ECV. © 2013 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  8. Determinants of pain perception after external cephalic version in pregnant women.

    Science.gov (United States)

    Truijens, Sophie E M; van der Zalm, Marieke; Pop, Victor J M; Kuppens, Simone M I

    2014-03-01

    A considerable proportion of pregnant women with a fetus in breech position refuses external cephalic version (ECV), with fear of pain as important barrier. As a consequence, they are at high risk for caesarean section at term. The current study investigated determinants of pain perception during ECV, with special attention to maternal mental state such as depression and fear of ECV. Prospective study of 249 third-trimester pregnant women with breech position with a request for an ECV attempt. Department of Obstetrics and Gynaecology in a large teaching hospital in the Netherlands. Prior to the ECV attempts, obstetric factors were registered, participants fulfilled the Edinburgh Depression Scale (EDS) and reported fear of ECV on a 10-point visual analog scale. Perception of pain intensity was measured with a 10-point visual analog scale, immediately after ECV. Multivariate linear regression analyses showed success of ECV to be the strongest predictor of pain perception. Furthermore, scores on the depression questionnaire and degree of fear of ECV independently explained pain perception, which was not the case for obstetrical or ECV related factors. Apart from ECV outcome, psychological factors like depression and fear of ECV were independently related to pain perception of an ECV attempt. Maternal mood state should be taken into account when offering an ECV attempt to women with a fetus in breech position. Due to the painful experience and the importance of successful outcome, ECV should only be attempted in institutions with experienced practitioners and with careful attention to maternal mood and the way a woman is coping with the ECV attempt. © 2013 Published by Elsevier Ltd.

  9. External cephalic version for singleton breech presentation: proposal of a practical check-list for obstetricians.

    Science.gov (United States)

    Indraccolo, U; Graziani, C; Di Iorio, R; Corona, G; Bonito, M; Indraccolo, S R

    2015-07-01

    External cephalic version (ECV) for breech presentation is not routinely performed by obstetricians in many clinical settings. The aim of this work is to assess to what extent the factors involved in performing ECV are relevant for the success and safety of ECV, in order to propose a practical check-list for assessing the feasibility of ECV. Review of 214 references. Factors involved in the success and risks of ECV (feasibility of ECV) were extracted and were scored in a semi-quantitative way according to textual information, type of publication, year of publication, number of cases. Simple conjoint analysis was used to describe the relevance found for each factor. Parity has the pivotal role in ECV feasibility (relevance 16.6%), followed by tocolysis (10.8%), gestational age (10.6%), amniotic fluid volume (4.7%), breech variety (1.9%), and placenta location (1.7%). Other factors with estimated relevance around 0 (regional anesthesia, station, estimated fetal weight, fetal position, obesity/BMI, fetal birth weight, duration of manoeuvre/number of attempts) have some role in the feasibility of ECV. Yet other factors, with negative values of estimated relevance, have even less importance. From a logical interpretation of the relevance of each factor assessed, ECV should be proposed with utmost prudence if a stringent check-list is followed. Such a check-list should take into account: parity, tocolytic therapy, gestational age, amniotic fluid volume, breech variety, placenta location, regional anesthesia, breech engagement, fetal well-being, uterine relaxation, fetal size, fetal position, fetal head grasping capability and fetal turning capability.

  10. Remifentanil analgesia during external cephalic version for breech presentation in nulliparous women at term

    Science.gov (United States)

    Wang, Zhi-Hong; Yang, Yi; Xu, Gui-Ping

    2017-01-01

    Abstract Background: The aim of the study was to assess the efficacy and safety of remifentanil for pain relief during external cephalic version (ECV) for breech presentation in nulliparous women at term. Methods: A total of 144 nulliparous women with singleton breech presentation were randomly divided into the intervention group and the placebo group, with 72 subjects in each group. The subjects in the intervention group received remifentanil (infused at 0.1 μg kg–1 min–1 with demand boluses of 0.1 μg/kg), whereas those in the placebo group were given saline placebo. This study was conducted from May 2013 to April 2016. The outcomes measures include pain (measured with the visual analog scale, VAS), success rate of ECV, maternal satisfaction for ECV, and adverse events. Results: A total of 137 participants completed the study. The intervention with remifentanil showed greater efficacy than did placebo in decreasing the VAS score immediately after ECV (intervention group 4.3 ± 2.2 vs placebo group 6.4 ± 2.5, P < 0.01). A significant difference in the ECV success rate was also found between the 2 groups (intervention group 56.9% vs placebo group 38.9%, P = 0.03). In addition, a significant difference in the satisfaction score was also detected (intervention group 9.3 ± 0.9 vs placebo group 6.7 ± 1.2, P < 0.01). The observed adverse events were similar between the 2 groups. Conclusion: This study shows that remifentanil could decrease pain, improve the ECV success rate, and improve satisfaction in nulliparous women at term during the period of ECV. Furthermore, it is also well tolerated with few adverse events. PMID:28296735

  11. A qualitative interview study exploring pregnant women's and health professionals' attitudes to external cephalic version.

    Science.gov (United States)

    Say, Rebecca; Thomson, Richard; Robson, Stephen; Exley, Catherine

    2013-01-16

    Women who have a breech presentation at term have to decide whether to attempt external cephalic version (ECV) and how they want to give birth if the baby remains breech, either by planned caesarean section (CS) or vaginal breech birth. The aim of this study was to explore the attitudes of women with a breech presentation and health professionals who manage breech presentation to ECV. We carried out semi-structured interviews with pregnant women with a breech presentation (n=11) and health professionals who manage breech presentation (n=11) recruited from two hospitals in North East England. We used purposive sampling to include women who chose ECV and women who chose planned CS. We analysed data using thematic analysis, comparing between individuals and seeking out disconfirming cases. Four main themes emerged from the data collected during interviews with pregnant women with a breech presentation: ECV as a means of enabling natural birth; concerns about ECV; lay and professional accounts of ECV; and breech presentation as a means of choosing planned CS. Some women's attitudes to ECV were affected by their preferences for how to give birth. Other women chose CS because ECV was not acceptable to them. Two main themes emerged from the interview data about health professionals' attitudes towards ECV: directive counselling and attitudes towards lay beliefs about ECV and breech presentation. Women had a range of attitudes to ECV informed by their preferences for how to give birth; the acceptability of ECV to them; and lay accounts of ECV, which were frequently negative. Most professionals described having a preference for ECV and reported directively counselling women to choose it. Some professionals were dismissive of lay beliefs about ECV. Some key challenges for shared decision making about breech presentation were identified: health professionals counselling women directively about ECV and the differences between evidence-based information about ECV and lay beliefs

  12. Hypnosis for the control of pain associated with external cephalic version: a comparative study.

    Science.gov (United States)

    Guittier, Marie-Julia; Guillemin, Francis; Farinelli, Edith Brandao; Irion, Olivier; Boulvain, Michel; de Tejada, Begoña Martinez

    2013-10-01

    To assess the effectiveness of hypnosis to reduce pain and facilitate external cephalic version (ECV). Cohort study. Geneva University Hospitals, Switzerland. 63 women attempting ECV under hypnosis from 2010 to 2011 were compared with 122 women who received standard care from 2005 through 2008. Immediately after the ECV attempt, both groups completed the same questionnaire evaluating the participants' pain (visual analogue and verbal rating scales) and experience with the procedure. Physicians also completed a questionnaire that elicited their views on the effect of hypnosis on the intervention. A chi-squared test was used to compare differences in proportions, and the Mann-Whitney U test was used for differences in continuous variables. A thematic content analysis of the obstetricians' responses to the open question regarding their experience of hypnotist accompaniment was also performed. Pain evaluated by women (visual analogue and verbal rating scales) and success rate of ECV. Pain intensity reported by women did not significantly differ between the hypnosis group and the standard care group (visual analogue scale score, 6.0 versus 6.3, respectively; p=.25; difference for verbal rating scale, p=0.31. In 72% of cases, physicians reported that hypnosis facilitated the procedure. The success rates in both groups were not significantly different (30% with hypnosis compared with 38% without; p=.31). Most women in both groups found the ECV attempt painful and a source of anxiety but would undergo it again if necessary. Hypnosis accompaniment during ECV does not reduce pain intensity associated with the procedure or improve the probability of a successful version.

  13. Anatomy of the lateral antebrachial cutaneous nerve in relation to the lateral epicondyle and cephalic vein.

    Science.gov (United States)

    Wongkerdsook, Wachara; Agthong, Sithiporn; Amarase, Chavarin; Yotnuengnit, Pattarapol; Huanmanop, Thanasil; Chentanez, Vilai

    2011-01-01

    The lateral antebrachial cutaneous nerve (LACN) is the terminal sensory branch of the musculocutaneous nerve supplying the lateral aspect of forearm. Because of its close proximity to the biceps brachii tendon (BBT), the lateral epicondyle (LE), and the cephalic vein (CV), surgery and venipuncture in the cubital fossa can injure the LACN. Measurement data regarding the relative anatomy of LACN are scarce. We, therefore, dissected 96 upper extremities from 26 males and 22 females to expose the LACN in the cubital fossa and forearm. The LACN consistently emerged from the lateral margin of BBT. It then pierced the deep fascia distal to the interepicondylar line (IEL) in 84.4% with mean distances of 1.8 ± 1.1 and 1.2 ± 0.9 cm (male and female, respectively). At the level of IEL, the LACN in all cases was medial to the LE (5.9 ± 1.1 cm male and 5.2 ± 0.9 cm female). Two types of branching were observed: single trunk (78.1%) and bifurcation (21.9%). Asymmetry in the branching pattern was observed in 6 males and 1 female. Concerning the relationship to the CV, the LACN ran medially within 1 cm at the level of IEL in 78.7%. Moreover, in 10 specimens, the LACN was directly beneath the CV. In the forearm, the LACN tends to course medial to the CV. Significant differences in the measurement data between genders but not sides were found in some parameters. These data are important for avoiding LACN injury and locating the LACN during relevant medical procedures. Copyright © 2010 Wiley-Liss, Inc.

  14. [External cephalic version for breech presentation at term: an effective procedure to reduce the caesarean section rate].

    Science.gov (United States)

    Lojacono, A; Donarini, G; Valcamonico, A; Soregaroli, M; Frusca, T

    2003-12-01

    Although term breech presentation is a relatively rare condition (3-5% of all births), it continues to be an important indication for caesarean section and has contributed to its increased use. Risk of complications may be increased for both mother and foetus in such a situation. Vaginal delivery of a breech presenting foetus is complex and may involve many difficulties, so today there is a general consensus that planned caesarean section is better than planned vaginal birth for the foetus in breech presentation at term. External cephalic version is one of the most effective procedures in modern obstetrics. It involves the external manipulation of the foetus from the breech into the cephalic presentation. A successful manoeuvre can decrease costs by avoiding operative deliveries and decreasing maternal morbidity. The aim of the present study is to evaluate the effectiveness of this obstetric manoeuvre to increase the proportion of vertex presentation among foetuses that were formerly in the breech position near term, so as to reduce the caesarean section rate. The safety of the version is also showed. From 1999 to 2002, 89 women with foetal breech presentation underwent external cephalic version at the Department of Obstetrics and Gynaecology of the Brescia University. The gestational age was 36.8+/-0.8 weeks. The following variables have been taken into consideration: breech variety, placental location, foetal back position, parity, amount of amniotic fluid and gestational age. Every attempt was performed with a prior use of an intravenous drip of Ritodrine, and foetal heart rate was monitored continuously with cardiotocogram. The success rate of the procedure was 42.7% (n=38). No maternal or foetal complication or side effects occurred, both during and after the manoeuvre, except a transient foetal bradycardia that resolved spontaneously. Only one spontaneous reversion of the foetus occurred before delivery. Of all the women that underwent a successful version

  15. Lessons learned from a single institution's retrospective analysis of emergent cesarean delivery following external cephalic version with and without neuraxial anesthesia.

    Science.gov (United States)

    Ainsworth, A; Sviggum, H P; Tolcher, M C; Weaver, A L; Holman, M A; Arendt, K W

    2017-05-01

    To evaluate the risk of emergent cesarean delivery with the use of neuraxial anesthesia for external cephalic version in a single practice. Randomized trials have shown increased external cephalic version success when neuraxial anesthesia is used, without additional risk. We hypothesized that in our actual clinical practice, outside the confines of randomized trials, neuraxial anesthesia could be associated with an increased risk of emergent cesarean delivery. This retrospective cohort study included all women who underwent external cephalic version at a single institution with and without neuraxial anesthesia. The primary outcome was the incidence of emergent cesarean delivery (defined as delivery within 4hours of version). Secondary outcomes were version success and ultimate mode of delivery. A total of 135 women underwent external cephalic version procedures; 58 with neuraxial anesthesia (43.0%) and 77 without (57.0%). Location of the procedure, tocolytic therapy, and gestational age were different between groups. An increased rate of emergent cesarean delivery was found in procedures with neuraxial anesthesia compared to procedures without (5/58 (8.6%) compared to 0/77 (0.0%); 95% CI for difference, 1.4 to 15.8%; P=0.013). In this single hospital's practice, patients who may be at higher risk of complications and have a lesser likelihood of success were provided NA for ECV. As a result, the use of neuraxial anesthesia for external cephalic version was associated with a higher rate of emergent cesarean delivery. Obstetric and anesthetic practices should evaluate their patient selection and procedure protocol for external cephalic version under neuraxial anesthesia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Outcomes of external cephalic version and breech presentation at term, an audit of deliveries at a Sydney tertiary obstetric hospital, 1997-2004.

    Science.gov (United States)

    Nassar, Natasha; Roberts, Christine L; Cameron, Carolyn A; Peat, Brian

    2006-01-01

    Probabilistic information on outcomes of breech presentation is important for clinical decision-making. We aim to quantify adverse maternal and fetal outcomes of breech presentation at term. We conducted an audit of 1,070 women with a term, singleton breech presentation who were classified as eligible or ineligible for external cephalic version or diagnosed in labor at a tertiary obstetric hospital in Australia, 1997-2004. Maternal, delivery and perinatal outcomes were assessed and frequency of events quantified. Five hundred and sixty (52%) women were eligible and 170 (16%) were ineligible for external cephalic version, 211 (20%) women were diagnosed in labor and 134 (12%) were unclassifiable. Seventy-one percent of eligible women had an external cephalic version, with a 39% success rate. Adverse outcomes of breech presentation at term were rare: immediate delivery for prelabor rupture of membranes (1.3%), nuchal cord (9.3%), cord prolapse (0.4%), and fetal death (0.3%); and did not differ by clinical classification. Women who had an external cephalic version had a reduced risk of onset-of-labor within 24 h (RR 0.25; 95%CI 0.08, 0.82) compared with women eligible for but who did not have an external cephalic version. Women diagnosed with breech in labor had the highest rates of emergency cesarean section (64%), cord prolapse (1.4%) and poorest infant outcomes. Adverse maternal and fetal outcomes of breech presentation at term are rare and there was no increased risk of complications after external cephalic version. Findings provide important data to quantify the frequency of adverse outcomes that will help facilitate informed decision-making and ensure optimal management of breech presentation.

  17. [External cephalic version in case of persisting breech presentation at term: motivations and women's experience of the intervention].

    Science.gov (United States)

    Pichon, M; Guittier, M-J; Irion, O; Boulvain, M

    2013-01-01

    To evaluate the efficacy and acceptability of external cephalic version (ECV). From 2004 to 2008, 212 pregnant women between 34-37 weeks of gestation with fetus in breech presentation were included in a randomized clinical trial and 125 externals cephalic versions were studied. A success rate of 37.6%t was recorded. At 34 weeks of gestation, 80.6% of women were considering an ECV in the event of persistent breech position at 37 weeks. These women expressed the desire to give birth vaginally (52% versus 24.4%, P<0.001). In contrast, others women preferred an elective cesarean section to avoid the risk of a breech vaginal delivery. Women felt pain during the ECV and scored 60 on average using the analogical visual scale. Women rated on a verbal rating scale the ECV as severely painful to unbearable (68%), and as stressful (70%). Despite this, the majority of women would recommend ECV to their friends or would be willing to repeat it for themselves. ECV remains a scary and painful medical procedure. More research is needed to reduce the impact. The use of analgesic medication for this indication is controversial. Hypnosis could be an alternative to evaluate. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  18. Central Neuraxial Blockade-Assisted External Cephalic Version in Reducing Caesarean Section Rate: Systematic Review and Meta-Analysis

    Science.gov (United States)

    Bolaji, Ibrahim; Alabi-Isama, Lillian

    2009-01-01

    We review the medical literature on the success, safety and economic value of central neuraxial blockade-assisted (CNB) external cephalic version from randomized controlled studies identified from 1951 to 2009. The result showed that more women had successful ECV with regional anaesthesia with corresponding reduction in caesarean section rate. They were 1.5 times more likely than women not receiving anaesthesia to have a successful ECV. The number to treat is six women needed to receive anaesthesia for 1 baby to be turned from breech to cephalic presentation. Feto-maternal morbidity was not increased in the CNB-aided group consisting of only transient bradycardia. Although the appropriate amount of force for safe version has not been quantified, there was no report of uterine rupture despite removal of these patients from “excessive force-pain biofeedback loop” induced through motor nerve blockade. We can attribute 30% of cost savings amounting to £42,150.00 directly to CNB using the most up to date Health Resource Group Code (HRG4). The initial results are encouraging but until the benefits and safety of CNB-aided ECV are substantiated by large randomized, blinded controlled trials, this practice cannot be universally recommended. PMID:20069044

  19. Central Neuraxial Blockade-Assisted External Cephalic Version in Reducing Caesarean Section Rate: Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Ibrahim Bolaji

    2009-01-01

    Full Text Available We review the medical literature on the success, safety and economic value of central neuraxial blockade-assisted (CNB external cephalic version from randomized controlled studies identified from 1951 to 2009. The result showed that more women had successful ECV with regional anaesthesia with corresponding reduction in caesarean section rate. They were 1.5 times more likely than women not receiving anaesthesia to have a successful ECV. The number to treat is six women needed to receive anaesthesia for 1 baby to be turned from breech to cephalic presentation. Feto-maternal morbidity was not increased in the CNB-aided group consisting of only transient bradycardia. Although the appropriate amount of force for safe version has not been quantified, there was no report of uterine rupture despite removal of these patients from “excessive force-pain biofeedback loop” induced through motor nerve blockade. We can attribute 30% of cost savings amounting to £42,150.00 directly to CNB using the most up to date Health Resource Group Code (HRG4. The initial results are encouraging but until the benefits and safety of CNB-aided ECV are substantiated by large randomized, blinded controlled trials, this practice cannot be universally recommended.

  20. Evaluation of the pharmacokinetics of imipenem following regional limb perfusion using the saphenous and the cephalic veins in standing horses.

    Science.gov (United States)

    Kelmer, G; Tatz, A J; Kdoshim, E; Britzi, M; Segev, G

    2017-10-01

    This prospective experimental study goal was to determine the pharmacokinetics of imipenem after intravenous regional limb perfusion (IV-RLP) in standing horses. Nine horses participated in the study; that was approved by the University Animal Care and Use Committee. One thoracic limb or one pelvic limb of each horse was randomly selected. After the veins were catheterized, an Esmarch bandage tourniquet was applied and the catheter was injected with a solution containing 500mg of imipenem. Synovial fluid samples were collected from the fetlock joint and blood samples were collected from the jugular vein. All samples were analyzed for imipenem concentration using liquid chromatography mass spectrometry. Cmax of imipenem in the fetlock joint using the cephalic and the saphenous vein was 87 and 60μg⁄mL, respectively. The results indicate that by performing IV-RLP using the cephalic/saphenous, one can achieve imipenem concentrations in the fetlock joint that are well above the MIC of most susceptible pathogens including resistant bacteria such as Methicillin Resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. Thus, with selective; judicious use, RLP with imipenem can markedly increase treatment efficacy of severe distal limb infections in horses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Interventions for helping to turn term breech babies to head first presentation when using external cephalic version.

    Science.gov (United States)

    Cluver, Catherine; Gyte, Gillian M L; Sinclair, Marlene; Dowswell, Therese; Hofmeyr, G Justus

    2015-02-09

    Breech presentation is associated with increased complications. Turning a breech baby to head first presentation using external cephalic version (ECV) attempts to reduce the chances of breech presentation at birth so as to avoid the adverse effects of breech vaginal birth or caesarean section. Interventions such as tocolytic drugs and other methods have been used in an attempt to facilitate ECV. To assess, from the best evidence available, the effects of interventions such as tocolysis, acoustic stimulation for midline spine position, regional analgesia (epidural or spinal), transabdominal amnioinfusion, systemic opioids and hypnosis, or the use of abdominal lubricants, on ECV at term for successful version, presentation at birth, method of birth and perinatal and maternal morbidity and mortality. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2014) and the reference lists of identified studies. Randomised and quasi-randomised trials comparing the above interventions with no intervention or other methods to facilitate ECV at term. We assessed eligibility and trial quality. Two review authors independently assessed for inclusion all potential studies identified as a result of the search strategy and independently extracted the data using a specially designed data extraction form. We included 28 studies, providing data on 2786 women. We used the random-effects model for pooling data because of clinical heterogeneity between studies. A number of trial reports gave insufficient information to allow clear assessment of risk of bias. We used GradePro software to carry out formal assessments of quality of the evidence for beta stimulants versus placebo and regional analgesia with tocolysis versus tocolysis alone.Tocolytic parenteral beta stimulants were effective in increasing cephalic presentations in labour (average risk ratio (RR) 1.68, 95% confidence interval (CI) 1.14 to 2.48, five studies, 459 women, low-quality evidence) and

  2. Comparative proteome and peptidome analysis of the cephalic fluid secreted by Arapaima gigas (Teleostei: Osteoglossidae) during and outside parental care.

    Science.gov (United States)

    Torati, Lucas S; Migaud, Hervé; Doherty, Mary K; Siwy, Justyna; Mullen, Willian; Mesquita, Pedro E C; Albalat, Amaya

    2017-01-01

    Parental investment in Arapaima gigas includes nest building and guarding, followed by a care provision when a cephalic fluid is released from the parents' head to the offspring. This fluid has presumably important functions for the offspring but so far its composition has not been characterised. In this study the proteome and peptidome of the cephalic secretion was studied in parental and non-parental fish using capillary electrophoresis coupled to mass spectrometry (CE-MS) and GeLC-MS/MS analyses. Multiple comparisons revealed 28 peptides were significantly different between males and parental males (PC-males), 126 between females and parental females (PC-females), 51 between males and females and 9 between PC-males and PC-females. Identification revealed peptides were produced in the inner ear (pcdh15b), eyes (tetraspanin and ppp2r3a), central nervous system (otud4, ribeye a, tjp1b and syn1) among others. A total of 422 proteins were also identified and gene ontology analysis revealed 28 secreted extracellular proteins. From these, 2 hormones (prolactin and stanniocalcin) and 12 proteins associated to immunological processes (serotransferrin, α-1-antitrypsin homolog, apolipoprotein A-I, and others) were identified. This study provides novel biochemical data on the lateral line fluid which will enable future hypotheses-driven experiments to better understand the physiological roles of the lateral line in chemical communication.

  3. Comparative proteome and peptidome analysis of the cephalic fluid secreted by Arapaima gigas (Teleostei: Osteoglossidae during and outside parental care.

    Directory of Open Access Journals (Sweden)

    Lucas S Torati

    Full Text Available Parental investment in Arapaima gigas includes nest building and guarding, followed by a care provision when a cephalic fluid is released from the parents' head to the offspring. This fluid has presumably important functions for the offspring but so far its composition has not been characterised. In this study the proteome and peptidome of the cephalic secretion was studied in parental and non-parental fish using capillary electrophoresis coupled to mass spectrometry (CE-MS and GeLC-MS/MS analyses. Multiple comparisons revealed 28 peptides were significantly different between males and parental males (PC-males, 126 between females and parental females (PC-females, 51 between males and females and 9 between PC-males and PC-females. Identification revealed peptides were produced in the inner ear (pcdh15b, eyes (tetraspanin and ppp2r3a, central nervous system (otud4, ribeye a, tjp1b and syn1 among others. A total of 422 proteins were also identified and gene ontology analysis revealed 28 secreted extracellular proteins. From these, 2 hormones (prolactin and stanniocalcin and 12 proteins associated to immunological processes (serotransferrin, α-1-antitrypsin homolog, apolipoprotein A-I, and others were identified. This study provides novel biochemical data on the lateral line fluid which will enable future hypotheses-driven experiments to better understand the physiological roles of the lateral line in chemical communication.

  4. Talcum powder or aqueous gel to aid external cephalic version: a randomised controlled trial

    Science.gov (United States)

    2014-01-01

    Background External cephalic version (ECV) is offered to reduce the number of Caesarean delivery indicated by breech presentation which occurs in 3-4% of term pregnancies. ECV is commonly performed aided by the application of aqueous gel or talcum powder to the maternal abdomen. We sought to compare gel with powder during ECV on achieving successful version and increasing tolerability. Method We enrolled 95 women (≥ 36 weeks gestation) on their attendance for planned ECV. All participants received terbutaline tocolysis. Regional anaesthesia was not used. ECV was performed in the standard fashion after the application of the allocated aid. If the first round (maximum of 2 attempts) of ECV failed, crossover to the opposing aid was permitted. Results 48 women were randomised to powder and 47 to gel. Self-reported procedure related median [interquartile range] pain scores (using a 10-point visual numerical rating scale VNRS; low score more pain) were 6 [5-9] vs. 8 [7-9] P = 0.03 in favor of gel. ECV was successful in 21/48 (43.8%) vs. 26/47 (55.3%) RR 0.6 95% CI 0.3-1.4 P = 0.3 for powder and gel arms respectively. Crossover to the opposing aid and a second round of ECV was performed in 13/27 (48.1%) following initial failure with powder and 4/21 (19%) after failure with gel (RR 3.9 95% CI 1.0-15 P = 0.07). ECV success rate was 5/13 (38.5%) vs. 1/4 (25%) P = 0.99 after crossover use of gel or powder respectively. Operators reported higher satisfaction score with the use of gel (high score, greater satisfaction) VNRS scores 6 [4.25-8] vs 8 [7-9] P = 0.01. Conclusion Women find gel use to be associated with less pain. The ECV success rate is not significantly different. Trial registration The trial is registered with ISRCTN (identifier ISRCTN87231556). PMID:24468078

  5. Randomized trial of anaesthetic interventions in external cephalic version for breech presentation.

    Science.gov (United States)

    Khaw, K S; Lee, S W Y; Ngan Kee, W D; Law, L W; Lau, T K; Ng, F F; Leung, T Y

    2015-06-01

    Successful external cephalic version (ECV) for breech presenting fetus reduces the need for Caesarean section (CS). We aimed to compare the success rate of ECV with either spinal anaesthesia (SA) or i.v. analgesia using remifentanil. In a double-phased, stratified randomized blinded controlled study we compared the success rates of ECV, performed under spinal anaesthesia (SA), i.v. analgesia (IVA) using remifentanil or no anaesthetic interventions. In phase I, 189 patients were stratified by parity before randomization to ECV, performed by blinded operators, under SA using either hyperbaric bupivacaine 9 mg with fentanyl 15 µg, i.v. remifentanil infusion 0.1 µg kg min(-1), or Control (no anaesthetic intervention). Operators performing ECV were blinded to the treatment allocation. In phase 2, patients in the Control group in whom the initial ECV failed were further randomized to receive either SA (n=9) or IVA (n=9) for a re-attempt. The primary outcome was the incidence of successful ECV. The success rate in Phase 1 was greatest using SA [52/63 (83%)], compared with IVA [40/63 (64%)] and Control [40/63 (64%)], (P=0.027). Median [IQR] pain scores on a visual analogue scale (range 0-100), were 0 [0-0] with SA, 35 [0-60] with IVA and 50 [30-75] in the Control group (P<0.001). Median [IQR] VAS sedation scores were highest with IVA [75 (50-80)], followed by SA, [0 (0-50)] and Control [0 (0-0)]. In phase 2, 7/9 (78%) of ECV re-attempts were successful with SA, whereas all re-attempts using IVA failed (P=0.0007). The incidence of fetal bradycardia necessitating emergency CS within 30 min, was similar among groups; 1.6% (1/63) in the SA and IVA groups and 3.2% (2/63) in the Control group. SA increased the success rate and reduced pain for both primary and re-attempts of ECV, whereas IVA using remifentanil infusion only reduced the pain. There was no significant increase in the incidence of fetal bradycardia or emergency CS, with ECV performed under anaesthetic

  6. Cost-effectiveness of external cephalic version for term breech presentation.

    Science.gov (United States)

    Tan, Jonathan M; Macario, Alex; Carvalho, Brendan; Druzin, Maurice L; El-Sayed, Yasser Y

    2010-01-21

    External cephalic version (ECV) is recommended by the American College of Obstetricians and Gynecologists to convert a breech fetus to vertex position and reduce the need for cesarean delivery. The goal of this study was to determine the incremental cost-effectiveness ratio, from society's perspective, of ECV compared to scheduled cesarean for term breech presentation. A computer-based decision model (TreeAge Pro 2008, Tree Age Software, Inc.) was developed for a hypothetical base case parturient presenting with a term singleton breech fetus with no contraindications for vaginal delivery. The model incorporated actual hospital costs (e.g., $8,023 for cesarean and $5,581 for vaginal delivery), utilities to quantify health-related quality of life, and probabilities based on analysis of published literature of successful ECV trial, spontaneous reversion, mode of delivery, and need for unanticipated emergency cesarean delivery. The primary endpoint was the incremental cost-effectiveness ratio in dollars per quality-adjusted year of life gained. A threshold of $50,000 per quality-adjusted life-years (QALY) was used to determine cost-effectiveness. The incremental cost-effectiveness of ECV, assuming a baseline 58% success rate, equaled $7,900/QALY. If the estimated probability of successful ECV is less than 32%, then ECV costs more to society and has poorer QALYs for the patient. However, as the probability of successful ECV was between 32% and 63%, ECV cost more than cesarean delivery but with greater associated QALY such that the cost-effectiveness ratio was less than $50,000/QALY. If the probability of successful ECV was greater than 63%, the computer modeling indicated that a trial of ECV is less costly and with better QALYs than a scheduled cesarean. The cost-effectiveness of a trial of ECV is most sensitive to its probability of success, and not to the probabilities of a cesarean after ECV, spontaneous reversion to breech, successful second ECV trial, or adverse

  7. Cost-effectiveness of external cephalic version for term breech presentation

    Directory of Open Access Journals (Sweden)

    Carvalho Brendan

    2010-01-01

    Full Text Available Abstract Background External cephalic version (ECV is recommended by the American College of Obstetricians and Gynecologists to convert a breech fetus to vertex position and reduce the need for cesarean delivery. The goal of this study was to determine the incremental cost-effectiveness ratio, from society's perspective, of ECV compared to scheduled cesarean for term breech presentation. Methods A computer-based decision model (TreeAge Pro 2008, Tree Age Software, Inc. was developed for a hypothetical base case parturient presenting with a term singleton breech fetus with no contraindications for vaginal delivery. The model incorporated actual hospital costs (e.g., $8,023 for cesarean and $5,581 for vaginal delivery, utilities to quantify health-related quality of life, and probabilities based on analysis of published literature of successful ECV trial, spontaneous reversion, mode of delivery, and need for unanticipated emergency cesarean delivery. The primary endpoint was the incremental cost-effectiveness ratio in dollars per quality-adjusted year of life gained. A threshold of $50,000 per quality-adjusted life-years (QALY was used to determine cost-effectiveness. Results The incremental cost-effectiveness of ECV, assuming a baseline 58% success rate, equaled $7,900/QALY. If the estimated probability of successful ECV is less than 32%, then ECV costs more to society and has poorer QALYs for the patient. However, as the probability of successful ECV was between 32% and 63%, ECV cost more than cesarean delivery but with greater associated QALY such that the cost-effectiveness ratio was less than $50,000/QALY. If the probability of successful ECV was greater than 63%, the computer modeling indicated that a trial of ECV is less costly and with better QALYs than a scheduled cesarean. The cost-effectiveness of a trial of ECV is most sensitive to its probability of success, and not to the probabilities of a cesarean after ECV, spontaneous reversion

  8. Interventions for helping to turn term breech babies to head first presentation when using external cephalic version

    Science.gov (United States)

    Cluver, Catherine; Hofmeyr, G Justus; Gyte, Gillian ML; Sinclair, Marlene

    2014-01-01

    Background Breech presentation is associated with increased complications. Turning a breech baby to head first presentation using external cephalic version (ECV) attempts to reduce the chances of breech presentation at birth, and reduce the adverse effects of breech vaginal birth or caesarean section. Tocolytic drugs and other methods have been used in an attempt to facilitate ECV. Objectives To assess interventions such as tocolysis, fetal acoustic stimulation, regional analgesia, transabdominal amnioinfusion or systemic opioids on ECV for a breech baby at term. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (30 September 2011) and the reference lists of identified studies. Selection criteria Randomised and quasi-randomised trials comparing the above interventions with no intervention or other methods to facilitate ECV at term. Data collection and analysis We assessed eligibility and trial quality. Two review authors independently assessed for inclusion all potential studies identified as a result of the search strategy and independently extracted the data using a designed data extraction form. Main results We included 25 studies, providing data on 2548 women. We used the random-effects model for pooling data due to clinical heterogeneity in the included studies in the various comparisons. The overall quality of the evidence was reasonable, but a number of assessments had insufficient data to provide an answer with any degree of assurance. Tocolytic drugs, in particular betastimulants, were effective in increasing cephalic presentations in labour (average risk ratio (RR) 1.38, 95% confidence interval (CI) 1.03 to 1.85, eight studies, 993 women) and in reducing the number of caesarean sections (average RR 0.82, 95% CI 0.71 to 0.94, eight studies, 1177 women). No differences were identified in fetal bradycardias (average RR 0.95, 95% CI 0.48 to 1.89, three studies, 467 women) although the review is underpowered for

  9. Patients' and professionals' barriers and facilitators to external cephalic version for breech presentation at term, a qualitative analysis in the Netherlands

    NARCIS (Netherlands)

    Rosman, A. N.; Vlemmix, F.; Fleuren, M. A H; Rijnders, M. E.; Beuckens, A.; Opmeer, Brent C; Mol, B.W.J.; van Zwieten, M.C.B.; Kok, M.

    Objective: external cephalic version (ECV) is a relatively simple and safe manoeuvre and a proven effective approach in the reduction of breech presentation at term. There is professional consensus that ECV should be offered to all women with a fetus in breech presentation, but only up to 70% of

  10. Patients' and professionals' barriers and facilitators to external cephalic version for breech presentation at term, a qualitative analysis in the Netherlands

    NARCIS (Netherlands)

    Rosman, A. N.; Vlemmix, F.; Fleuren, M. A. H.; Rijnders, M. E.; Beuckens, A.; Opmeer, B. C.; Mol, B. W. J.; van Zwieten, M. C. B.; Kok, M. [=Marjolein

    2014-01-01

    external cephalic version (ECV) is a relatively simple and safe manoeuvre and a proven effective approach in the reduction of breech presentation at term. There is professional consensus that ECV should be offered to all women with a fetus in breech presentation, but only up to 70% of women eligible

  11. Facilitators and barriers to external cephalic version for breech presentation at term among health care providers in the Netherlands: a quantitative analysis

    NARCIS (Netherlands)

    Rosman, Ageeth N.; Vlemmix, Floortje; Beuckens, Antje; Rijnders, Marlies E.; Opmeer, Brent C.; Mol, Ben Willem J.; Kok, Marjolein; Fleuren, Margot A. H.

    2014-01-01

    guidelines recommend that external cephalic version (ECV) should be offered to all women with a fetus in breech presentation at term. However, only 50-60% of the women receive an ECV attempt. We explored the determinants (barriers and facilitators) affecting the uptake of the guidelines among

  12. Patients' and professionals' barriers and facilitators to external cephalic version for breech presentation at term, a qualitative analysis in the Netherlands

    NARCIS (Netherlands)

    Rosman, A.N.; Vlemmix, F.; Fleuren, M.A.H.; Rijnders, M.E.; Beuckens, A.; Opmeer, B.C.; Mol, B.W.J.; Zwieten, M.C.B. van; Kok, M.

    2014-01-01

    Objective: external cephalic version (ECV) is a relatively simple and safe manoeuvre and a proven effective approach in the reduction of breech presentation at term. There is professional consensus that ECV should be offered to all women with a fetus in breech presentation, but only up to 70% of

  13. Facilitators and barriers to external cephalic version for breech presentation at term among health care providers in the Netherlands: A quantitative analysis

    NARCIS (Netherlands)

    Rosman, A.N.; Vlemmix, F.; Beuckens, A.; Rijnders, M.E.; Opmeer, B.C.; Mol, B.W.J.; Kok, M.; Fleuren, M.A.H.

    2014-01-01

    OBJECTIVE: guidelines recommend that external cephalic version (ECV) should be offered to all women with a fetus in breech presentation at term. However, only 50-60% of the women receive an ECV attempt. We explored the determinants (barriers and facilitators) affecting the uptake of the guidelines

  14. Cephalic Duodeno-Pancreatectomy with Pancreatic-Gastric Anastomosis with Double Purse String, in Patient with Lithiasis and Tumoral Jaundice - Case Report

    Directory of Open Access Journals (Sweden)

    Tudor A

    2014-10-01

    Full Text Available Introduction: One of the most feared complications after cephalic duodeno-pancreatectomy remains pancreatic fistula. In recent years, various methods of pancreatico-digestive reconstruction were performed in order to reduce the rate of pancreatic fistula. One of these methods is pancreatico-gastric reconstruction by using two purse string threads.

  15. Neuraxial analgesia to increase the success rate of external cephalic version: a systematic review and meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Magro-Malosso, Elena Rita; Saccone, Gabriele; Di Tommaso, Mariarosaria; Mele, Michele; Berghella, Vincenzo

    2016-09-01

    External cephalic version is a medical procedure in which the fetus is externally manipulated to assume the cephalic presentation. The use of neuraxial analgesia for facilitating the version has been evaluated in several randomized clinical trials, but its potential effects are still controversial. The objective of the study was to evaluate the effectiveness of neuraxial analgesia as an intervention to increase the success rate of external cephalic version. Searches were performed in electronic databases with the use of a combination of text words related to external cephalic version and neuraxial analgesia from the inception of each database to January 2016. We included all randomized clinical trials of women, with a gestational age ≥36 weeks and breech or transverse fetal presentation, undergoing external cephalic version who were randomized to neuraxial analgesia, including spinal, epidural, or combined spinal-epidural techniques (ie, intervention group) or to a control group (either intravenous analgesia or no treatment). The primary outcome was the successful external cephalic version. The summary measures were reported as relative risk or as mean differences with a 95% confidence interval. Nine randomized clinical trials (934 women) were included in this review. Women who received neuraxial analgesia had a significantly higher incidence of successful external cephalic version (58.4% vs 43.1%; relative risk, 1.44, 95% confidence interval, 1.27-1.64), cephalic presentation in labor (55.1% vs 40.2%; relative risk, 1.37, 95% confidence interval, 1.08-1.73), and vaginal delivery (54.0% vs 44.6%; relative risk, 1.21, 95% confidence interval, 1.04-1.41) compared with those who did not. Women who were randomized to the intervention group also had a significantly lower incidence of cesarean delivery (46.0% vs 55.3%; relative risk, 0.83, 95% confidence interval, 0.71-0.97), maternal discomfort (1.2% vs 9.3%; relative risk, 0.12, 95% confidence interval, 0

  16. Successful external cephalic version is an independent factor for caesarean section during trial of labor - a matched controlled study.

    Science.gov (United States)

    Boujenah, J; Fleury, C; Bonneau, C; Pharisien, I; Tigaizin, A; Carbillon, L

    2017-12-01

    To assess the mode of delivery and Caesarean Section (CS) rate after successful External Cephalic Version (ECV). A matched case-control study. Data were gathered from a tertiary care university hospital register from 1996-2015. All pregnant women who delivered after successful External Cephalic Version (ECV). Among 643 women who attempted ECV, we identified 198 with successful ECVs and compared them with the next two women who presented for labor management with spontaneous cephalic presentation, matching for delivery date, maternal age, parity, body mass index, and delivery history using univariate and stepwise logistic regression. The main outcome measure was the risk of caesarean. The caesarean section rate was higher after successful ECV (respectively 20.7% versus 7.07%, P<0.05). Caesarean section for abnormal fetal head position (forehead, bregma, face) was higher after successful ECV (28.6% versus 0%). After adjustment for matching and confounding variables (variation of the caesarean section rate over the study period, gestational maternal complications, antepartum fetal complications, term of delivery, induction of labor, oxytocin use for dystocia, neonatal cephalic perimeter), a successful ECV increased the risk of caesarean section (adjusted OR 3.17, 95% CI 1.86-5.46). By stratifying on week, a trend for increased risk for caesarean section was observed at the week after ECV and at post term (28.6% before 37+6, 14.8% at 38+0-38+6, 13.8% at 39+0-39+6, 14.2% at 40+0-40+6 and 33.3% beyond 41+0 weeks' gestation, P=0.06). Women who have a successful ECV are at increased risk of caesarean section compared with women who experience spontaneous cephalic presentation. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  17. Isolation of endothelial colony-forming cells from blood samples collected from the jugular and cephalic veins of healthy adult horses.

    Science.gov (United States)

    Sharpe, Ashley N; Seeto, Wen J; Winter, Randolph L; Zhong, Qiao; Lipke, Elizabeth A; Wooldridge, Anne A

    2016-10-01

    OBJECTIVE To evaluate optimal isolation of endothelial colony-forming cells (ECFCs) from peripheral blood of horses. SAMPLE Jugular and cephalic venous blood samples from 17 adult horses. PROCEDURES Each blood sample was divided; isolation was performed with whole blood adherence (WBA) and density gradient centrifugation (DGC). Isolated cells were characterized by uptake of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein (DiI-Ac-LDL), vascular tubule formation, and expression of endothelial (CD34, CD105, vascular endothelial growth factor receptor-2, and von Willebrand factor) and hematopoietic (CD14) cell markers by use of indirect immunofluorescence assay (IFA) and flow cytometry. RESULTS Colonies with cobblestone morphology were isolated from 15 of 17 horses. Blood collected from the cephalic vein yielded colonies significantly more often (14/17 horses) than did blood collected from the jugular vein (8/17 horses). Of 14 cephalic blood samples with colonies, 13 were obtained with DGC and 8 with WBA. Of 8 jugular blood samples with colonies, 8 were obtained with DGC and 4 with WBA. Colony frequency (colonies per milliliter of blood) was significantly higher for cephalic blood samples and samples isolated with DGC. Cells formed vascular tubules, had uptake of DiI-Ac-LDL, and expressed endothelial markers by use of IFA and flow cytometry, which confirmed their identity as ECFCs. CONCLUSIONS AND CLINICAL RELEVANCE Maximum yield of ECFCs was obtained for blood samples collected from both the jugular and cephalic veins and use of DGC to isolate cells. Consistent yield of ECFCs from peripheral blood of horses will enable studies to evaluate diagnostic and therapeutic uses.

  18. Comparison of Venous Return Characteristics with Right Ventricular Mechanics During Cephalic Fluid Shift

    Science.gov (United States)

    Elliott, Morgan; Martin, David

    2015-01-01

    For my summer internship project, I organized a pilot study to analyze the effects of a cephalic fluid shift on venous return and right ventricular mechanics to increase right ventricular and venous knowledge. To accomplish this pilot study, I wrote a testing protocol, obtained Institutional Review Board (IRB) approval, completed subject payment forms, lead testing sessions, and analyzed the data. This experiment used -20deg head down tilt (20 HDT) as the ground based simulation for the fluid shift that occurs during spaceflight and compared it to data obtained from the seated and supine positions. Using echocardiography, data was collected for the right ventricle, hepatic vein, internal jugular vein, external jugular vein, and inferior vena cava. Additionally, non-invasive venous pressure measurements, similar to those soon to be done in-orbit, were collected. It was determined that the venous return from below the heard is increased during 20 HDT, which was supported by increased hepatic vein velocities, increased right ventricular inflow, and increased right ventricular strain at 20 HDT relative to seated values. Jugular veins in the neck undergo an increase in pressure and area, but no significant increase in flow, relative to seated values when a subject is tilted 20 HDT. Contrary to the initial expectations based on this jugular flow, there was no significant increase in central venous pressure, as evidenced by no change in Doppler indices for right arterial pressure or inferior vena cava diameter. It is suspected that these differences in pressure are due to the hydrostatic pressure indifference point shifting during tilt; there is a potential for a similar phenomenon with microgravity. This data will hopefully lead to a more in-depth understanding of the response of the body to microgravity and how those relate to the previously mentioned cardiovascular risk of fluid shift that is associated with spaceflight. These results were presented in greater detail

  19. Wernicke's encephalopathy after cephalic pancreaticoduodenectomy Encefalopatía de Wernicke tras duodenopancreatectomía cefálica

    Directory of Open Access Journals (Sweden)

    Francisco Gabriel Onieva-González

    2011-11-01

    Full Text Available Wernicke's encephalopathy is an acute neurological disorder resulting from thiamine deficiency. We report a case in a young patient who underwent a cephalic duodenopancreatectomy with a bleeding duodenal ulcer refractory to endoscopic and surgical treatment, requiring total parenteral nutrition, without thiamine supplementation.La encefalopatía de Wernicke (EW es un trastorno neurológico agudo resultado del déficit de tiamina. Presentamos la aparición de dicho cuadro en un enfermo joven que es sometido a una duodenopancreatectomía cefálica ante una úlcera duodenal sangrante refractaria a tratamiento endoscópico y quirúrgico previo, precisando de una nutrición parenteral total, sin suplementos de tiamina.

  20. Fetal heart rate abnormalities during and after external cephalic version: Which fetuses are at risk and how are they delivered?

    Science.gov (United States)

    Kuppens, Simone M; Smailbegovic, Ida; Houterman, Saskia; de Leeuw, Ingrid; Hasaart, Tom H

    2017-10-17

    Fetal heart rate abnormalities (FHR) during and after external cephalic version (ECV) are relatively frequent. They may raise concern about fetal wellbeing. Only occasionally they may lead to an emergency cesarean section. Prospective cohort study in 980 women (> 34 weeks gestation) with a singleton fetus in breech presentation. During and after external cephalic version (ECV) FHR abnormalities were recorded. Obstetric variables and delivery outcome were evaluated. Primary outcome was to identify which fetuses are at risk for FHR abnormalities. Secondary outcome was to identify a possible relationship between FHR abnormalities during and after ECV and mode of delivery and fetal distress during subsequent labor. The overall success rate of ECV was 60% and in 9% of the attempts there was an abnormal FHR pattern. In two cases FHR abnormalities after ECV led to an emergency CS. Estimated fetal weight per 100 g (OR 0.90, CI: 0.87-0.94) and longer duration of the ECV-procedure (OR 1.13, CI: 1.05-1.21) were factors significantly associated with the occurrence of FHR abnormalities. FHR abnormalities were not associated with the mode of delivery or the occurrence of fetal distress during subsequent labor. FHR abnormalities during and after ECV are more frequent with lower estimated fetal weight and longer duration of the procedure. FHR abnormalities during and after ECV have no consequences for subsequent mode of delivery. They do not predict whether fetal distress will occur during labor. The Eindhoven Breech Intervention Study, NCT00516555 . Date of registration: August 13, 2007.

  1. Effect of Intrathecal Bupivacaine Dose on the Success of External Cephalic Version for Breech Presentation: A Prospective, Randomized, Blinded Clinical Trial.

    Science.gov (United States)

    Chalifoux, Laurie A; Bauchat, Jeanette R; Higgins, Nicole; Toledo, Paloma; Peralta, Feyce M; Farrer, Jason; Gerber, Susan E; McCarthy, Robert J; Sullivan, John T

    2017-10-01

    Breech presentation is a leading cause of cesarean delivery. The use of neuraxial anesthesia increases the success rate of external cephalic version procedures for breech presentation and reduces cesarean delivery rates for fetal malpresentation. Meta-analysis suggests that higher-dose neuraxial techniques increase external cephalic version success to a greater extent than lower-dose techniques, but no randomized study has evaluated the dose-response effect. We hypothesized that increasing the intrathecal bupivacaine dose would be associated with increased external cephalic version success. We conducted a randomized, double-blind trial to assess the effect of four intrathecal bupivacaine doses (2.5, 5.0, 7.5, 10.0 mg) combined with fentanyl 15 μg on the success rate of external cephalic version for breech presentation. Secondary outcomes included mode of delivery, indication for cesarean delivery, and length of stay. A total of 240 subjects were enrolled, and 239 received the intervention. External cephalic version was successful in 123 (51.5%) of 239 patients. Compared with bupivacaine 2.5 mg, the odds (99% CI) for a successful version were 1.0 (0.4 to 2.6), 1.0 (0.4 to 2.7), and 0.9 (0.4 to 2.4) for bupivacaine 5.0, 7.5, and 10.0 mg, respectively (P = 0.99). There were no differences in the cesarean delivery rate (P = 0.76) or indication for cesarean delivery (P = 0.82). Time to discharge was increased 60 min (16 to 116 min) with bupivacaine 7.5 mg or higher as compared with 2.5 mg (P = 0.004). A dose of intrathecal bupivacaine greater than 2.5 mg does not lead to an additional increase in external cephalic procedural success or a reduction in cesarean delivery.

  2. Cephalic pancreaticoduodenectomy with preservation of a right coronary artery bypass graft using the right gastro-epiploic artery: a case report.

    Science.gov (United States)

    Homsy, K; Paquay, J-L; Farghadani, H

    2018-02-20

    Pancreatic cancer is a rare disease with a high mortality rate, for which complete surgical resection, when possible, is the preferred therapeutic. Pancreaticoduodenectomy represents the surgical technique of choice. Abdominal surgeons can be faced with the challenge of patients with a history of coronary artery bypass graft in which the right gastro-epiploic artery is used. We report the case of a patient with an adenocarcinoma of the pancreatic head, stage IIA, having previously undergone a triple coronary artery bypass, one of which being a right gastro-epiploic graft. Our challenge was underlined by the necessity of a complete oncological resection through a cephalic pancreaticoduodenectomy while preserving the necessary cardiac perfusion via the right gastro-epiploic artery. We have been able to preserve a right gastro-epiploic artery as a coronary bypass during a cephalic pancreaticoduodenectomy for a cephalic pancreatic adenocarcinoma. We have successfully been able to preserve and re-implant the right gastro-epiploic artery to the origin of the gastroduodenal artery while insuring R0 resection of the tumor. A coronary artery bypass using the right gastro-epiploic artery should therefore not be considered as an obstacle to a Whipple's procedure if total oncological resection is obtainable.

  3. Obstetrical and neonatal outcomes following unsuccessful external cephalic version: a stratified analysis amongst failures, successes, and controls.

    Science.gov (United States)

    Balayla, Jacques; Dahdouh, Elias M; Villeneuve, Sophie; Boucher, Marc; Gauthier, Robert J; Audibert, François; Fuchs, Florent

    2015-03-01

    Though on average one out of every two external cephalic versions (ECV) fails to rotate the breech fetus, little is known about the outcomes of pregnancies in which ECV is unsuccessful. The objective of the present study is to compare obstetrical and neonatal outcomes following failure of ECV, relative to cases of breech controls without an attempt at ECV. We conducted a retrospective, population-based, cohort study using the CDC's Birth Data files from the US for the year 2006. We stratified the cohort according to fetal presentation and ECV status: success, failure, and no ECV (controls). The effect of failure of ECV on the risk of several neonatal and obstetrical outcomes was estimated using logistic regression analysis, adjusting for relevant confounders. We analyzed a total of 4 273 225 births, out of which 183 323 (4.3%) met inclusion criteria. Relative to breech controls, failed ECV occurred more frequently amongst Caucasian, college-educated, married women bearing a female fetus. Compared to no ECV, failure of ECV was associated with increased odds of PROM (aOR, 1.75; 95% CI, 1.60-1.90), elective cesarean delivery (aOR, 1.53; 95% CI, 1.36-1.72), cesarean delivery in labor (aOR, 1.38; 95% CI, 1.21-1.57), abnormal fetal heart tracing (aOR, 1.78; 95% CI, 1.50-2.11), assisted ventilation at birth (aOR, 1.50; 95% CI, 1.27-1.78), 5-min APGAR scores <7 (aOR, 1.35; 95% CI, 1.20-1.51), and NICU admission (aOR, 1.48; 95% CI, 1.20-1.82). The delayed spontaneous fetal restitution rate was 13%. When stratifying controls with regards to trial of labor status, the increased risk of failed ECV persisted for cesarean delivery, NICU admission, assisted ventilation and abnormal fetal tracing, independently of whether a trial of labor took place. Relative to breech controls without attempt at ECV, failure of ECV to restitute cephalic presentation appears to be associated with an increased risk of adverse perinatal and obstetrical outcomes.

  4. The Early External Cephalic Version (ECV) 2 Trial: an international multicentre randomised controlled trial of timing of ECV for breech pregnancies.

    Science.gov (United States)

    Hutton, E K; Hannah, M E; Ross, S J; Delisle, M-F; Carson, G D; Windrim, R; Ohlsson, A; Willan, A R; Gafni, A; Sylvestre, G; Natale, R; Barrett, Y; Pollard, J K; Dunn, M S; Turtle, P

    2011-04-01

    To investigate whether initiating external cephalic version (ECV) earlier in pregnancy might increase the rate of successful ECV procedures, and be more effective in decreasing the rate of non-cephalic presentation at birth and of caesarean section. An unblinded multicentred randomised controlled trial. A total of 1543 women were randomised from 68 centres in 21 countries. Women with a singleton breech fetus at a gestational age of 33(0/7) weeks (231 days) to 35(6/7) weeks (251 days) of gestation were included. Participants were randomly assigned to having a first ECV procedure between the gestational ages of 34(0/7) (238 days) and 35(6/7) weeks of gestation (early ECV group) or at or after 37(0/7) (259 days) weeks of gestation (delayed ECV group). The primary outcome was the rate of caesarean section; the secondary outcome was the rate of preterm birth. Fewer fetuses were in a non-cephalic presentation at birth in the early ECV group (314/765 [41.1%] versus 377/768 [49.1%] in the delayed ECV group; relative risk [RR] 0.84, 95% CI 0.75, 0.94, P=0.002). There were no differences in rates of caesarean section (398/765 [52.0%] versus 430/768 [56.0%]; RR 0.93, 95% CI 0.85, 1.02, P=0.12) or in risk of preterm birth (50/765 [6.5%] versus 34/768 [4.4%]; RR 1.48, 95% CI 0.97, 2.26, P=0.07) between groups. External cephalic version at 34-35 weeks versus 37 or more weeks of gestation increases the likelihood of cephalic presentation at birth but does not reduce the rate of caesarean section and may increase the rate of preterm birth. © 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2011 RCOG.

  5. Factors affecting the success of moxibustion in the management of a breech presentation as a preliminary treatment to external cephalic version.

    Science.gov (United States)

    Manyande, Anne; Grabowska, Christine

    2009-12-01

    to explore the effects of moxibustion treatment, to examine the predictors of its use in causing a breech presentation to spontaneously turn to a cephalic presentation which will result in a vaginal birth (the paper will refer to this as 'successful') and offer external cephalic version (ECV) subsequently after moxibustion treatment when the fetus remains in a breech presentation. a prospective study over a two-year time period from February 2004 until January 2006. 76 pregnant women from various acupuncture practices in the UK, with a third trimester breech presentation. the acupuncturist taught the women how to apply moxibustion (sticks of compressed dried herbs-Artemisia vulgaris) treatment at home by stimulating the acupoint on the outer edge at the base of the little toe nail for seven days twice a day (morning and afternoon). If the breech presentation persisted after treatment, ECV was carried out towards the end of the pregnancy. The obstetricians offered this during the routine antenatal hospital visits. the results show that following treatment with moxibustion, 31 (40.8%) of the breech presentations spontaneously turned to cephalic presentations, and a further 33 (43.4%) breech presentations were turned by ECV. Women who involved other people in the administration of moxibustion were twice as likely to be successful. Multiparous women were also 16% more likely than primiparous women to succeed in achieving a spontaneous version with the use of moxibustion. Fewer side effects reported when using moxibustion were the strongest predictor of successful spontaneous cephalic version with an odds ratio of 12% (p = 0.02). moxibustion creates a better chance of vaginal birth for expectant mothers. Of the women who were successful in turning their babies using moxibustion, 88% went on to have a normal birth and 12% had a caesarean section. Moxibustion treatment also significantly increases version from a breech presentation to a cephalic presentation where there

  6. Complications of external cephalic version: a retrospective analysis of 1121 patients at a tertiary hospital in Sydney.

    Science.gov (United States)

    Rodgers, R; Beik, N; Nassar, N; Brito, I; de Vries, B

    2017-04-01

    To report the complication rate associated with external cephalic version (ECV) at term. Single-centre retrospective study. A major tertiary hospital in Sydney, Australia. All women who underwent an ECV at Royal Prince Alfred Hospital from 1995-2013 were included. ECV was attempted on all consenting women with a breech presentation at term in the absence of contraindications. Complications were classified as minor (transient cardiotocography abnormalities, ruptured membranes, small antepartum haemorrhage) or serious (fetal death, placental abruption, fetal distress requiring emergency caesarean section, fetal bone injury, cord prolapse). ECV success rates and rate of reversion to breech were recorded. The primary outcome was the incidence of serious complications. Secondary outcome measures were the rate of minor complications and reversion to breech. Of 1121 patients that underwent ECV, five (0.45%) experienced a serious complication. There was one placental abruption, one emergency caesarean section for fetal distress and two cord prolapses. There was one fetal death attributable to a successful ECV. Forty-eight women (4.28%) experienced a minor complication. Reversion to the breech occurred in sixteen patients (3.32%). ECV at term is associated with a low rate of serious complications. Study of 1121 consecutive ECV attempts shows low rate of complications although one fetal death reported. © 2016 Royal College of Obstetricians and Gynaecologists.

  7. Clinical outcomes after external cephalic version with spinal anesthesia after failure of a first attempt without anesthesia.

    Science.gov (United States)

    Massalha, Manal; Garmi, Gali; Zafran, Noah; Carmeli, Julia; Gimburg, Genady; Salim, Raed

    2017-12-01

    To determine whether repeat external cephalic version (ECV) with spinal anesthesia affects clinical outcomes and cesarean delivery rates. A retrospective study was conducted using data collected at one hospital in Israel between January 1, 2009, and December 31, 2015. Women with non-vertex singleton pregnancies (≥37 weeks) who had a failed ECV attempt without spinal anesthesia were included in the analysis. All women were offered a repeat ECV with spinal anesthesia. Outcomes assessed were rates of vertex presentation at delivery, successful repeat ECV, and cesarean delivery. Overall, 145 of 213 ECV attempts without spinal anesthesia were successful. Of the 68 women with a failed attempt, 5 (7%) experienced spontaneous version and 18 (26%) delivered at another institution or went into spontaneous labor. Among the remaining 45 women, 28 (62%) agreed to a repeat ECV with spinal anesthesia; 11 (39%) of these procedures were successful. All 11 women experienced vertex presentation at delivery versus none of the 17 women who refused repeat ECV (P=0.003). The cesarean delivery rate was 64% (18/28) versus 100% (17/17), respectively (P=0.007). Repeat ECV with spinal anesthesia after a failed first attempt without spinal anesthesia increased vertex presentation at birth and decreased the rate of cesarean delivery. © 2017 International Federation of Gynecology and Obstetrics.

  8. Brief report: a cost analysis of neuraxial anesthesia to facilitate external cephalic version for breech fetal presentation.

    Science.gov (United States)

    Carvalho, Brendan; Tan, Jonathan M; Macario, Alex; El-Sayed, Yasser Y; Sultan, Pervez

    2013-07-01

    In this study, we sought to determine whether neuraxial anesthesia to facilitate external cephalic version (ECV) increased delivery costs for breech fetal presentation. Using a computer cost model, which considers possible outcomes and probability uncertainties at the same time, we estimated total expected delivery costs for breech presentation managed by a trial of ECV with and without neuraxial anesthesia. From published studies, the average probability of successful ECV with neuraxial anesthesia was 60% (with individual studies ranging from 44% to 87%) compared with 38% (with individual studies ranging from 31% to 58%) without neuraxial anesthesia. The mean expected total delivery costs, including the cost of attempting/performing ECV with anesthesia, equaled $8931 (2.5th-97.5th percentile prediction interval $8541-$9252). The cost was $9207 (2.5th-97.5th percentile prediction interval $8896-$9419) if ECV was attempted/performed without anesthesia. The expected mean incremental difference between the total cost of delivery that includes ECV with anesthesia and ECV without anesthesia was $-276 (2.5th-97.5th percentile prediction interval $-720 to $112). The total cost of delivery in women with breech presentation may be decreased (up to $720) or increased (up to $112) if ECV is attempted/performed with neuraxial anesthesia compared with ECV without neuraxial anesthesia. Increased ECV success with neuraxial anesthesia and the subsequent reduction in breech cesarean delivery rate offset the costs of providing anesthesia to facilitate ECV.

  9. A prospective study of the factors associated with the success rate of external cephalic version for breech presentation at term.

    Science.gov (United States)

    Burgos, Jorge; Melchor, Juan Carlos; Pijoán, José Ignacio; Cobos, Patricia; Fernández-Llebrez, Luis; Martínez-Astorquiza, Txantón

    2011-01-01

    To determine the factors associated with the success rate of external cephalic version (ECV) for breech presentation at term. A prospective analysis of 500 ECV maneuvers. The variables maternal age, maternal weight, body mass index, previous cesarean delivery, gestational age, parity, amount of amniotic fluid, placental location, and type of breech were studied using logistic regression analysis. The success rate of ECV was 52.2% (n=261). The variables significantly associated with success were parity, placental location, amount of amniotic fluid, and type of breech (Pbreech presentation had a 2.77-times higher success rate compared with a frank breech presentation (95% CI, 1.16-6.62). The area under the ROC curve showed a predictive ability of 73.6% (95% CI, 69.2%-77.9%) for these 3 variables. Parity, placental location, amount of amniotic fluid, and type of breech presentation were associated with the success rate of ECV. Copyright © 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  10. External cephalic version for breech presentation at term: predictors of success, and impact on the rate of caesarean section.

    Science.gov (United States)

    Hussin, O A; Mahmoud, M A; Abdel-Fattah, M M

    2013-02-01

    The incidence of caesarean section for breech presentation has increased markedly in the last 20 years. A prospective, interventional cohort study was carried out of the success rate of external cephalic version (ECV) and its predictors of as well as its impact on the rate of caesarean section for vaginal breech delivery. All 128 women admitted during the study period to the obstetrics department of a tertiary care military hospital in Taif, Saudi Arabia with breech presentation at term, regardless of age and parity, who accepted ECV were recruited. ECV was successful in 53.9% of the women. Most of the women with successful ECV delivered normally (84.1%) and only 14.5% of them delivered by caesarean section. Conversely, normal vaginal delivery was reported among 8.5% of those who had spontaneous version with failed ECV and approximately two-thirds of them delivered by caesarean section (62.7%). Successful ECV reduced the breech and caesarean section rate.

  11. Villous duodenal adenoma with II and III grade dysplasia and carcinoma in situ treated with cephalic duodenopancreatectomy

    Directory of Open Access Journals (Sweden)

    Čolović Radoje

    2006-01-01

    Full Text Available Background. Villous duodenal adenomas are rare, tend to malignant alteration and recurrence if surgical procedures are not sufficiently radical. They are mostly localized in the second portion of the duodenum and close to a papilla and are prone to malignant alteration. Case report. In this paper we presented a 79-year-old female patient already operated on twice elsewhere due to obstructive jaundice caused by villous duodenal adenoma, using, firstly, cholecystectomy and T-tube drainage of the choledoclus, and, then, an unsuccessful attempt of radical surgery − duodenopancreatectomy. The patient was some time wearing a T-tube drainage, and, then, submitted to endoscopic papillotomy, endoscopic stenting, and, finally to the insertion of a self-expandable metallic stent which got clogged three months later causing chalangitis. Three years following the first surgery, the patient presented to our institution and submitted to cephalic duodenopancreatectomy. Histology confirmed villous duodenal adenomas with II and III grade dysplasia and carcinoma in situ. The lymph nodes were tumour-free. The postoperative recovery was somewhat prolonged due to cardiologic difficulties and a mild infection of the wound. Conclusion. Villous duodenal adenoma is curable if treated correctly and in a proper time. Radical treatment delay increases the risk for malignant alteration which was the case with our patient who was submitted to it three years after the histologic confirmation of the diagnosis.

  12. Phylogeny and revision of the bee genus Rhinocorynura Schrottky (Hymenoptera, Apidae, Augochlorini, with comments on its female cephalic polymorphism

    Directory of Open Access Journals (Sweden)

    Rodrigo B. Gonçalves

    2012-03-01

    Full Text Available Phylogeny and revision of the bee genus Rhinocorynura Schrottky (Hymenoptera, Apidae, Augochlorini, with comments on its female cephalic polymorphism. A taxonomic revision and a phylogeny for the species of Rhinocorynura are provided. Six species are recognized: R. briseis, R. crotonis, R. inflaticeps and R. vernoniae stat. nov., the latter removed from synonymy with R. inflaticeps, in addition to two newly described species, R. brunnea sp. nov. and R. viridis sp. nov. Lectotypes for Halictus crotonis Ducke, 1906 and Halictus inflaticeps Ducke, 1906 are hereby designated. Another available name included in Rhinocorynura, Corynuropsis ashmeadi Schrottky, 1909, is removed from the genus and treated as species inquerenda in Augochlorini. Rhinocorynura is monophyletic in the phylogenetic analysis and the following relationships were found among its species: (R. crotonis (R. briseis ((R. brunnea sp. nov. + R. viridis sp. nov. (R. inflaticeps + R. vernoniae. Biogeographic relationships within the genus and comparisons with related taxa are presented. Females of all species exhibit pronounced variation in body size, in two of them, R. inflaticeps and R. vernoniae, with structural modifications possibly linked to division of labor. Identification key and illustrations for the species are provided.

  13. Dynamics

    CERN Document Server

    Goodman, Lawrence E

    2001-01-01

    Beginning text presents complete theoretical treatment of mechanical model systems and deals with technological applications. Topics include introduction to calculus of vectors, particle motion, dynamics of particle systems and plane rigid bodies, technical applications in plane motions, theory of mechanical vibrations, and more. Exercises and answers appear in each chapter.

  14. Remifentanil analgesia during external cephalic version for breech presentation in nulliparous women at term: A randomized controlled trial.

    Science.gov (United States)

    Wang, Zhi-Hong; Yang, Yi; Xu, Gui-Ping

    2017-03-01

    The aim of the study was to assess the efficacy and safety of remifentanil for pain relief during external cephalic version (ECV) for breech presentation in nulliparous women at term. A total of 144 nulliparous women with singleton breech presentation were randomly divided into the intervention group and the placebo group, with 72 subjects in each group. The subjects in the intervention group received remifentanil (infused at 0.1 μg kg min with demand boluses of 0.1 μg/kg), whereas those in the placebo group were given saline placebo. This study was conducted from May 2013 to April 2016. The outcomes measures include pain (measured with the visual analog scale, VAS), success rate of ECV, maternal satisfaction for ECV, and adverse events. A total of 137 participants completed the study. The intervention with remifentanil showed greater efficacy than did placebo in decreasing the VAS score immediately after ECV (intervention group 4.3 ± 2.2 vs placebo group 6.4 ± 2.5, P < 0.01). A significant difference in the ECV success rate was also found between the 2 groups (intervention group 56.9% vs placebo group 38.9%, P = 0.03). In addition, a significant difference in the satisfaction score was also detected (intervention group 9.3 ± 0.9 vs placebo group 6.7 ± 1.2, P < 0.01). The observed adverse events were similar between the 2 groups. This study shows that remifentanil could decrease pain, improve the ECV success rate, and improve satisfaction in nulliparous women at term during the period of ECV. Furthermore, it is also well tolerated with few adverse events.

  15. A qualitative interview study exploring pregnant women’s and health professionals’ attitudes to external cephalic version

    Science.gov (United States)

    2013-01-01

    Background Women who have a breech presentation at term have to decide whether to attempt external cephalic version (ECV) and how they want to give birth if the baby remains breech, either by planned caesarean section (CS) or vaginal breech birth. The aim of this study was to explore the attitudes of women with a breech presentation and health professionals who manage breech presentation to ECV. Methods We carried out semi-structured interviews with pregnant women with a breech presentation (n=11) and health professionals who manage breech presentation (n=11) recruited from two hospitals in North East England. We used purposive sampling to include women who chose ECV and women who chose planned CS. We analysed data using thematic analysis, comparing between individuals and seeking out disconfirming cases. Results Four main themes emerged from the data collected during interviews with pregnant women with a breech presentation: ECV as a means of enabling natural birth; concerns about ECV; lay and professional accounts of ECV; and breech presentation as a means of choosing planned CS. Some women’s attitudes to ECV were affected by their preferences for how to give birth. Other women chose CS because ECV was not acceptable to them. Two main themes emerged from the interview data about health professionals’ attitudes towards ECV: directive counselling and attitudes towards lay beliefs about ECV and breech presentation. Conclusions Women had a range of attitudes to ECV informed by their preferences for how to give birth; the acceptability of ECV to them; and lay accounts of ECV, which were frequently negative. Most professionals described having a preference for ECV and reported directively counselling women to choose it. Some professionals were dismissive of lay beliefs about ECV. Some key challenges for shared decision making about breech presentation were identified: health professionals counselling women directively about ECV and the differences between evidence

  16. [Fewer caesarean sections for breech presentation following external cephalic version according to a protocol in a special office visit].

    Science.gov (United States)

    Kuppens, S M I; Hasaart, T H M; van der Donk, M W P; Huibers, M; Franssen, M J; de Becker, B M J; Wijnen, H A A; Pop, V J M

    2008-06-07

    Identification of determinants affecting the outcome of external cephalic version (ECV) in breech presentation, and investigation of the impact of ECV--performed according to a standardized protocol in an outpatient clinic--on the mode of delivery. Retrospective analysis. In 2003 a standardized protocol of ECV was developed in the outpatient clinic for obstetrics of the Catharina Hospital in Eindhoven, the Netherlands; it was tested in 'version office visits'. Obstetric characteristics of all pregnant women who underwent attempts of ECV in the clinic from January 2004 until June 2006 during these sessions, and the subsequent births, were analysed. 85% of all ECVs were performed by the same hospital midwife and gynaecologist, in accordance with the protocol. ECV was successful in 96 of 209 pregnant women (46%). In 1 pregnant woman an emergency caesarean section was performed after ECV because of partial abruptio placentae. Nulliparity, incomplete breech presentation and low birth weight of the baby were associated with a lower success rate of ECV in this study. In the group with a successful ECV the percentage of caesarean deliveries was substantially lower (9 versus 83%; odds ratio: 0.21; 95% CI: 0.09-0.51). A regular team consisting of a hospital midwife and a gynaecologist working according to a standardized protocol for ECV in a case of breech presentation proved successful: the number of term breech presentations substantially diminished and therefore the percentage of caesarean sections was lower in the group in which ECV had been successful. This could have considerable impact on health care in the Netherlands in terms of reduced maternal morbidity and cost savings.

  17. A qualitative interview study exploring pregnant women’s and health professionals’ attitudes to external cephalic version

    Directory of Open Access Journals (Sweden)

    Say Rebecca

    2013-01-01

    Full Text Available Abstract Background Women who have a breech presentation at term have to decide whether to attempt external cephalic version (ECV and how they want to give birth if the baby remains breech, either by planned caesarean section (CS or vaginal breech birth. The aim of this study was to explore the attitudes of women with a breech presentation and health professionals who manage breech presentation to ECV. Methods We carried out semi-structured interviews with pregnant women with a breech presentation (n=11 and health professionals who manage breech presentation (n=11 recruited from two hospitals in North East England. We used purposive sampling to include women who chose ECV and women who chose planned CS. We analysed data using thematic analysis, comparing between individuals and seeking out disconfirming cases. Results Four main themes emerged from the data collected during interviews with pregnant women with a breech presentation: ECV as a means of enabling natural birth; concerns about ECV; lay and professional accounts of ECV; and breech presentation as a means of choosing planned CS. Some women’s attitudes to ECV were affected by their preferences for how to give birth. Other women chose CS because ECV was not acceptable to them. Two main themes emerged from the interview data about health professionals’ attitudes towards ECV: directive counselling and attitudes towards lay beliefs about ECV and breech presentation. Conclusions Women had a range of attitudes to ECV informed by their preferences for how to give birth; the acceptability of ECV to them; and lay accounts of ECV, which were frequently negative. Most professionals described having a preference for ECV and reported directively counselling women to choose it. Some professionals were dismissive of lay beliefs about ECV. Some key challenges for shared decision making about breech presentation were identified: health professionals counselling women directively about ECV and the

  18. Characterization of Multi-Drug Resistant Enterococcus faecalis Isolated from Cephalic Recording Chambers in Research Macaques (Macaca spp.).

    Science.gov (United States)

    Woods, Stephanie E; Lieberman, Mia T; Lebreton, Francois; Trowel, Elise; de la Fuente-Núñez, César; Dzink-Fox, Joanne; Gilmore, Michael S; Fox, James G

    2017-01-01

    Nonhuman primates are commonly used for cognitive neuroscience research and often surgically implanted with cephalic recording chambers for electrophysiological recording. Aerobic bacterial cultures from 25 macaques identified 72 bacterial isolates, including 15 Enterococcus faecalis isolates. The E. faecalis isolates displayed multi-drug resistant phenotypes, with resistance to ciprofloxacin, enrofloxacin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, bacitracin, and erythromycin, as well as high-level aminoglycoside resistance. Multi-locus sequence typing showed that most belonged to two E. faecalis sequence types (ST): ST 4 and ST 55. The genomes of three representative isolates were sequenced to identify genes encoding antimicrobial resistances and other traits. Antimicrobial resistance genes identified included aac(6')-aph(2"), aph(3')-III, str, ant(6)-Ia, tetM, tetS, tetL, ermB, bcrABR, cat, and dfrG, and polymorphisms in parC (S80I) and gyrA (S83I) were observed. These isolates also harbored virulence factors including the cytolysin toxin genes in ST 4 isolates, as well as multiple biofilm-associated genes (esp, agg, ace, SrtA, gelE, ebpABC), hyaluronidases (hylA, hylB), and other survival genes (ElrA, tpx). Crystal violet biofilm assays confirmed that ST 4 isolates produced more biofilm than ST 55 isolates. The abundance of antimicrobial resistance and virulence factor genes in the ST 4 isolates likely relates to the loss of CRISPR-cas. This macaque colony represents a unique model for studying E. faecalis infection associated with indwelling devices, and provides an opportunity to understand the basis of persistence of this pathogen in a healthcare setting.

  19. Characterization of Multi-Drug Resistant Enterococcus faecalis Isolated from Cephalic Recording Chambers in Research Macaques (Macaca spp..

    Directory of Open Access Journals (Sweden)

    Stephanie E Woods

    Full Text Available Nonhuman primates are commonly used for cognitive neuroscience research and often surgically implanted with cephalic recording chambers for electrophysiological recording. Aerobic bacterial cultures from 25 macaques identified 72 bacterial isolates, including 15 Enterococcus faecalis isolates. The E. faecalis isolates displayed multi-drug resistant phenotypes, with resistance to ciprofloxacin, enrofloxacin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, bacitracin, and erythromycin, as well as high-level aminoglycoside resistance. Multi-locus sequence typing showed that most belonged to two E. faecalis sequence types (ST: ST 4 and ST 55. The genomes of three representative isolates were sequenced to identify genes encoding antimicrobial resistances and other traits. Antimicrobial resistance genes identified included aac(6'-aph(2", aph(3'-III, str, ant(6-Ia, tetM, tetS, tetL, ermB, bcrABR, cat, and dfrG, and polymorphisms in parC (S80I and gyrA (S83I were observed. These isolates also harbored virulence factors including the cytolysin toxin genes in ST 4 isolates, as well as multiple biofilm-associated genes (esp, agg, ace, SrtA, gelE, ebpABC, hyaluronidases (hylA, hylB, and other survival genes (ElrA, tpx. Crystal violet biofilm assays confirmed that ST 4 isolates produced more biofilm than ST 55 isolates. The abundance of antimicrobial resistance and virulence factor genes in the ST 4 isolates likely relates to the loss of CRISPR-cas. This macaque colony represents a unique model for studying E. faecalis infection associated with indwelling devices, and provides an opportunity to understand the basis of persistence of this pathogen in a healthcare setting.

  20. Experimental study of the long-term effects of cephalic irradiation on local cerebral circulation. Preliminary results

    International Nuclear Information System (INIS)

    Dufour, R.

    1978-01-01

    The purpose of this experimental study was to follow the effects of fractionated cehalic irradiation (average dosee 100 rads) on local cerebral blood circulation. Observations were made on unanaesthetized rabbits in terms of two circulatory responses, one of which is associated with rapid eye movement sleep and the other produced by inhalation of a mixture of air and 5% carbon dioxide. Both responses take the form of a characteristic increase in cerebral flow. The method of measuring variations in local cerebral flow relies on changes in the thermal conduction of cerebral tissue associated with the changes in circulation. Placement of the measuring probes entails fixation of electrodes for deriving the cortical and hippocampal electroencephalographic activity. The prreliminary results refer to two animalswhich were subjected to three andd four cephalic irradiations off 1000 rads, spaced at least a month apart, at a dose rate of 70 rad min -1 . The increase and the rate of increase of cerebral flow during rapid eye movement sleep and COBinhalation proved significantly greater than the reference values from the third month on (after the second irradiation) in the case of one animal and from the sixth month on (after the third irradiation) in the case of the other. The response during rapid eye movement sleep was equal to 140% of the reference amplitude during the two observation periods in the first case, and to 110 and 150% respectively after the third and fourth irradiations in the second case. The CO 2 response was 140% of the reference value during the two observation periods in the first case, and 135% after the third and fourth irradiations in the second case. The functional significance of these changes in cerebral output is analysed in terms of the regulation of cerebral circulation. (author)

  1. Botulinum toxin type A for cephalic cutaneous allodynia in chronic migraine: a randomized, double-blinded, placebo-controlled trial

    Directory of Open Access Journals (Sweden)

    Luciano Hollanda

    2014-12-01

    Full Text Available Cephalic allodynia (CA can be observed in 50-70% of patients with chronic migraine (CM. The aim of this trial was to assess the efficacy of botulinum toxin type A (Botx-A in the treatment of CA associated with CM. In this placebo-controlled trial, patients were randomized either into Botx-A or 0.9% saline injections and efficacy measures were assessed every 4 weeks for 3 months. Efficacy endpoints were number of migraine episodes associated with CA, changes from baseline in visual analogical scale scores for pain (VAS and frequency of common analgesics use for migraine. A total of 38 subjects were randomized to saline (n=18 or Botx-A (n=20. There were no significant differences in baseline between active intervention or placebo groups regarding mean age, number of headache episodes [mean 12.1 (9.22 and 17.00 (9.69 respectively; P=0.12], pain severity as measured by the VAS or frequency of analgesic use for headache episodes. Efficacy analysis showed that Botx-A injections led to an important decrease from baseline in the mean migraine episodes associated with CA after 12 weeks (5.20 versus 11.17; P=0.01. Also, VAS scores and frequency of analgesics use for headache were significantly reduced in the Botx-A group. This study suggests that Botx-A injections are superior to saline in the treatment of CA associated with CM, with mild self limited side effects.

  2. Accounting for center in the Early External Cephalic Version trials: an empirical comparison of statistical methods to adjust for center in a multicenter trial with binary outcomes.

    Science.gov (United States)

    Reitsma, Angela; Chu, Rong; Thorpe, Julia; McDonald, Sarah; Thabane, Lehana; Hutton, Eileen

    2014-09-26

    Clustering of outcomes at centers involved in multicenter trials is a type of center effect. The Consolidated Standards of Reporting Trials Statement recommends that multicenter randomized controlled trials (RCTs) should account for center effects in their analysis, however most do not. The Early External Cephalic Version (EECV) trials published in 2003 and 2011 stratified by center at randomization, but did not account for center in the analyses, and due to the nature of the intervention and number of centers, may have been prone to center effects. Using data from the EECV trials, we undertook an empirical study to compare various statistical approaches to account for center effect while estimating the impact of external cephalic version timing (early or delayed) on the outcomes of cesarean section, preterm birth, and non-cephalic presentation at the time of birth. The data from the EECV pilot trial and the EECV2 trial were merged into one dataset. Fisher's exact method was used to test the overall effect of external cephalic version timing unadjusted for center effects. Seven statistical models that accounted for center effects were applied to the data. The models included: i) the Mantel-Haenszel test, ii) logistic regression with fixed center effect and fixed treatment effect, iii) center-size weighted and iv) un-weighted logistic regression with fixed center effect and fixed treatment-by-center interaction, iv) logistic regression with random center effect and fixed treatment effect, v) logistic regression with random center effect and random treatment-by-center interaction, and vi) generalized estimating equations. For each of the three outcomes of interest approaches to account for center effect did not alter the overall findings of the trial. The results were similar for the majority of the methods used to adjust for center, illustrating the robustness of the findings. Despite literature that suggests center effect can change the estimate of effect in

  3. Phylogeny and revision of the bee genus Rhinocorynura Schrottky (Hymenoptera, Apidae, Augochlorini, with comments on its female cephalic polymorphism

    Directory of Open Access Journals (Sweden)

    Rodrigo B. Gonçalves

    2012-03-01

    Full Text Available Phylogeny and revision of the bee genus Rhinocorynura Schrottky (Hymenoptera, Apidae, Augochlorini, with comments on its female cephalic polymorphism. A taxonomic revision and a phylogeny for the species of Rhinocorynura are provided. Six species are recognized: R. briseis, R. crotonis, R. inflaticeps and R. vernoniae stat. nov., the latter removed from synonymy with R. inflaticeps, in addition to two newly described species, R. brunnea sp. nov. and R. viridis sp. nov. Lectotypes for Halictus crotonis Ducke, 1906 and Halictus inflaticeps Ducke, 1906 are hereby designated. Another available name included in Rhinocorynura, Corynuropsis ashmeadi Schrottky, 1909, is removed from the genus and treated as species inquerenda in Augochlorini. Rhinocorynura is monophyletic in the phylogenetic analysis and the following relationships were found among its species: (R. crotonis (R. briseis ((R. brunnea sp. nov. + R. viridis sp. nov. (R. inflaticeps + R. vernoniae. Biogeographic relationships within the genus and comparisons with related taxa are presented. Females of all species exhibit pronounced variation in body size, in two of them, R. inflaticeps and R. vernoniae, with structural modifications possibly linked to division of labor. Identification key and illustrations for the species are provided.Filogenia e revisão taxonômica das abelhas do gênero Rhinocorynura Schrottky (Hymenoptera, Apidae, Augochlorini, com comentários sobre o poliformismo cefálico das fêmeas. São apresentadas uma revisão taxonômica e filogenia para as espécies de Rhinocorynura. Seis espécies são reconhecidas, duas descritas como novas, R. brunnea sp. nov. e R. viridis sp. nov., e quatro com nomes disponíveis, R. briseis, R. crotonis, R. inflaticeps e R. vernoniae stat. nov., esta última removida da sinonímia com R. inflaticeps. Designam-se aqui lectótipos para Halictus crotonis Ducke, 1906 e Halictus inflaticeps Ducke, 1906. Outro nome disponível incluído em

  4. Congenital high airway obstruction syndrome in the breech presentation managed by ex utero intrapartum treatment procedure after intraoperative external cephalic version.

    Science.gov (United States)

    Miwa, Ichiro; Sase, Masakatsu; Nakamura, Yasuhiko; Hasegawa, Keiko; Kawasaki, Masahiro; Ueda, Kazuyuki

    2012-05-01

    Congenital high airway obstruction syndrome (CHAOS) caused by laryngeal atresia was diagnosed by prenatal ultrasound in a male fetus at 26 weeks of gestation. Findings included massive ascites, subcutaneous edema, enlarged hyperechogenic lungs with diaphragmatic inversion, dilated trachea, polyhydramnios, and breech presentation. Those findings of CHAOS spontaneously returned to normal by 33 weeks of gestation. However, the placenta was localized to the anterior uterine wall. In addition, the fetal position had been breech until delivery. At 36 weeks of gestation, a planned ex utero intrapartum treatment (EXIT) procedure was performed following intraoperative external cephalic version (ECV) in which the fetus was approached from the posterior wall of the uterus. Laryngoscopy revealed the predicted laryngeal obstruction, and tracheostomy was placed. Intraoperative ECV may be a useful technique in breech presentation before EXIT procedure. © 2012 The Authors. Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology.

  5. Absorbed doses received by infants subjected to panoramic dental and cephalic radiographs; Dosis absorbida recibida por infantes sometidos a radiografias dentales panoramicas y cefalicas

    Energy Technology Data Exchange (ETDEWEB)

    Carrizales, L.; Carreno, S. [Instituto Venezolano de Investigaciones Cientificas. Laboratorio Secundario de Calibracion Dosimetrica. Carretera Panamericana Km. 11. Apartado Postal 21827, Caracas (Venezuela)

    1998-12-31

    The IAEA Report No. 115 recommends that each country or region can establish levels of absorbed doses for each radiographic technique employed in diagnostic. assuming the extended and expensive of this purpose, we have been to begin in a first step with the dentistry area, in order to estimate the dose levels received at crystalline and thyroid level in infants that go to an important public institution in our country to realize panoramic and cephalic radiographs. This work will serve to justify and impel a quality assurance program in Venezuela on the dentistry area which includes aspects such as training for the medical lap referring the justification of the radiological practice, optimization of X-ray units to produce an adequate image quality that delivers to patient an absorbed dose as much lower as reasonably it can be reached without diagnostic detriment. (Author)

  6. Absorbed doses received by infants subjected to panoramic dental and cephalic radiographs; Dosis absorbida recibida por infantes sometidos a radiografias dentales panoramicas y cefalicas

    Energy Technology Data Exchange (ETDEWEB)

    Carrizales, L; Carreno, S [Instituto Venezolano de Investigaciones Cientificas. Laboratorio Secundario de Calibracion Dosimetrica. Carretera Panamericana Km. 11. Apartado Postal 21827, Caracas (Venezuela)

    1999-12-31

    The IAEA Report No. 115 recommends that each country or region can establish levels of absorbed doses for each radiographic technique employed in diagnostic. assuming the extended and expensive of this purpose, we have been to begin in a first step with the dentistry area, in order to estimate the dose levels received at crystalline and thyroid level in infants that go to an important public institution in our country to realize panoramic and cephalic radiographs. This work will serve to justify and impel a quality assurance program in Venezuela on the dentistry area which includes aspects such as training for the medical lap referring the justification of the radiological practice, optimization of X-ray units to produce an adequate image quality that delivers to patient an absorbed dose as much lower as reasonably it can be reached without diagnostic detriment. (Author)

  7. Sugar-induced cephalic-phase insulin release is mediated by a T1r2+T1r3-independent taste transduction pathway in mice.

    Science.gov (United States)

    Glendinning, John I; Stano, Sarah; Holter, Marlena; Azenkot, Tali; Goldman, Olivia; Margolskee, Robert F; Vasselli, Joseph R; Sclafani, Anthony

    2015-09-01

    Sensory stimulation from foods elicits cephalic phase responses, which facilitate digestion and nutrient assimilation. One such response, cephalic-phase insulin release (CPIR), enhances glucose tolerance. Little is known about the chemosensory mechanisms that activate CPIR. We studied the contribution of the sweet taste receptor (T1r2+T1r3) to sugar-induced CPIR in C57BL/6 (B6) and T1r3 knockout (KO) mice. First, we measured insulin release and glucose tolerance following oral (i.e., normal ingestion) or intragastric (IG) administration of 2.8 M glucose. Both groups of mice exhibited a CPIR following oral but not IG administration, and this CPIR improved glucose tolerance. Second, we examined the specificity of CPIR. Both mouse groups exhibited a CPIR following oral administration of 1 M glucose and 1 M sucrose but not 1 M fructose or water alone. Third, we studied behavioral attraction to the same three sugar solutions in short-term acceptability tests. B6 mice licked more avidly for the sugar solutions than for water, whereas T1r3 KO mice licked no more for the sugar solutions than for water. Finally, we examined chorda tympani (CT) nerve responses to each of the sugars. Both mouse groups exhibited CT nerve responses to the sugars, although those of B6 mice were stronger. We propose that mice possess two taste transduction pathways for sugars. One mediates behavioral attraction to sugars and requires an intact T1r2+T1r3. The other mediates CPIR but does not require an intact T1r2+T1r3. If the latter taste transduction pathway exists in humans, it should provide opportunities for the development of new treatments for controlling blood sugar. Copyright © 2015 the American Physiological Society.

  8. Use of External Cephalic Version and Amnioreduction in the Delivery of a Fetal Demise with Macrocephaly Secondary to Massive Intracranial Teratoma.

    Science.gov (United States)

    Blitz, Matthew J; Greeley, Elizabeth; Tam, Hima Tam; Rochelson, Burton

    2015-04-01

    Introduction Congenital intracranial tumors are rare and often incidentally diagnosed on routine ultrasound. We report a case of a fetal demise with a massive intracranial teratoma at 25 weeks of gestation and the management of her delivery in the setting of macrocephaly, breech presentation, and polyhydramnios. Case A 31-year-old G3P1011 woman at 25 weeks' gestation presented with a recent fetal demise and a fetal intracranial tumor first identified at 16 weeks' gestational age. The patient had declined termination of pregnancy. Biometry was consistent with 24 weeks' gestation, except for a head circumference of 394.4 mm consistent with 39 weeks' gestation. The fetus was in a breech presentation. An external cephalic version (ECV) was successfully performed under epidural anesthesia and an amnioreduction was then performed to stabilize the fetal position. Immediate induction of labor and vaginal delivery followed. Discussion ECV and amnioreduction may help facilitate delivery in cases of fetal demise complicated by macrocephaly, malpresentation, and polyhydramnios.

  9. [Impact of the external cephalic version on the obstetrical prognosis in a team with a high success rate of vaginal delivery in breech presentation].

    Science.gov (United States)

    Coppola, C; Mottet, N; Mariet, A S; Baeza, C; Poitrey, E; Bourtembourg, A; Ramanah, R; Riethmuller, D

    2016-10-01

    To analyse the impact of external cephalic version (ECV) on caesarean section rate in a team with a high success rate of vaginal delivery in breech presentation. Retrospective monocentric study including 298 patients with a breech presentations between 33 and 35weeks of amenorrhea followed at our university hospital and delivered after 35weeks, between 1st January 2011 and 31st December 2013. Patients were divided into 2 groups: planned ECV (n=216 patients) versus no planned ECV (n=57 patients). Our rate of successful vaginal breech delivery over the period of the study was 61.1%. We performed 165 ECV, with a 21.8% success rate. The average term of the attempt of ECV was 36.7weeks of amenorrhea. The caesarean section rate was not significantly different in the planned ECV group, even after adjustment on age, parity and previous caesarean delivery (adjusted OR=1.67 [0.77-3.61]). Attempt of ECV did not reduce the number of breech presentation at delivery (61.1% versus 61.4% [P=0.55]). Planned ECV in our center with a high level of breech vaginal delivery did not significantly impact our cesarean section rate. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  10. Facilitators and barriers to external cephalic version for breech presentation at term among health care providers in the Netherlands: a quantitative analysis.

    Science.gov (United States)

    Rosman, Ageeth N; Vlemmix, Floortje; Beuckens, Antje; Rijnders, Marlies E; Opmeer, Brent C; Mol, Ben Willem J; Kok, Marjolein; Fleuren, Margot A H

    2014-03-01

    guidelines recommend that external cephalic version (ECV) should be offered to all women with a fetus in breech presentation at term. However, only 50-60% of the women receive an ECV attempt. We explored the determinants (barriers and facilitators) affecting the uptake of the guidelines among gynaecologists and midwives in the Netherlands. national online survey. the Netherlands. gynaecologists and midwives. in the online survey, we identified the determinants that positively or negatively influenced the professionals׳ adherence to three key recommendations in the guidelines: (a) counselling, (b) advising for ECV, (c) arranging an ECV. Determinants were identified in a previously performed qualitative study and were categorised into five underlying constructs; attitude towards ECV, professional obligation, outcome expectations, self-efficacy and preconditions for successful ECV. We performed a multivariate analysis to assess the importance of the different constructs for adherence to the guideline. 364 professionals responded to the survey. Adherence varied: 84% counselled, 73% advised, and 82% arranged an ECV for (almost) all their clients. Although 90% of respondents considered ECV to be an effective treatment for preventing caesarean childbirths, only 30% agreed that 'every client should undergo ECV'. Self-efficacy (perceived skills) was the most important determinant influencing adherence. self-efficacy appears to be the most significant determinant for counselling, advising and arranging an ECV. to improve adherence to the guidelines on ECV we must improve self-efficacy. Copyright © 2014. Published by Elsevier Ltd.

  11. Use of External Cephalic Version and Amnioreduction in the Delivery of a Fetal Demise with Macrocephaly Secondary to Massive Intracranial Teratoma

    Directory of Open Access Journals (Sweden)

    Matthew J. Blitz

    2015-04-01

    Full Text Available Introduction - Congenital intracranial tumors are rare and often incidentally diagnosed on routine ultrasound. We report a case of a fetal demise with a massive intracranial teratoma at 25 weeks of gestation and the management of her delivery in the setting of macrocephaly, breech presentation, and polyhydramnios. Case - A 31-year-old G3P1011 woman at 25 weeks' gestation presented with a recent fetal demise and a fetal intracranial tumor first identified at 16 weeks' gestational age. The patient had declined termination of pregnancy. Biometry was consistent with 24 weeks' gestation, except for a head circumference of 394.4 mm consistent with 39 weeks' gestation. The fetus was in a breech presentation. An external cephalic version (ECV was successfully performed under epidural anesthesia and an amnioreduction was then performed to stabilize the fetal position. Immediate induction of labor and vaginal delivery followed. Discussion - ECV and amnioreduction may help facilitate delivery in cases of fetal demise complicated by macrocephaly, malpresentation, and polyhydramnios.

  12. Reducing the cesarean delivery rates for breech presentations: administration of spinal anesthesia facilitates manipulation to cephalic presentation, but is it cost saving?

    Science.gov (United States)

    2014-01-01

    Background External cephalic version (ECV) is infrequently performed and 98% of breech presenting fetuses are delivered surgically. Neuraxial analgesia can increase the success rate of ECV significantly, potentially reducing cesarean delivery rates for breech presentation. The current study aims to determine whether the additional cost to the hospital of spinal anesthesia for ECV is offset by cost savings generated by reduced cesarean delivery. Methods In our tertiary hospital, three variables manpower, disposables, and fixed costs were calculated for ECV, ECV plus anesthetic doses of spinal block, vaginal delivery and cesarean delivery. Total procedure costs were compared for possible delivery pathways. Manpower data were obtained from management payroll, fixed costs by calculating cost/lifetime usage rate and disposables were micro-costed in 2008, expressed in 2013 NIS. Results Cesarean delivery is the most expensive option, 11670.54 NIS and vaginal delivery following successful ECV under spinal block costs 5497.2 NIS. ECV alone costs 960.21 NIS, ECV plus spinal anesthesia costs 1386.97 NIS. The highest individual cost items for vaginal, cesarean delivery and ECV were for manpower. Expensive fixed costs for cesarean delivery included operating room trays and postnatal hospitalization (minimum 3 days). ECV with spinal block is cheaper due to lower expected cesarean delivery rate and its lower associated costs. Conclusions The additional cost of the spinal anesthesia is offset by increased success rates for the ECV procedure resulting in reduction in the cesarean delivery rate. PMID:24564984

  13. Postural change from lateral to supine is an important mechanism enhancing cephalic spread after injection of intrathecal 0.5% plain bupivacaine for cesarean section.

    Science.gov (United States)

    Xu, F; Qian, M; Wei, Y; Wang, Y; Wang, J; Li, M; Zhang, Y; Zhao, Y; Guo, X

    2015-11-01

    Spinal anesthesia is widely used for cesarean section, but the factors that affect the spread of the block in pregnant patients are still not fully explained. This study was designed to investigate the effect of postural changes on sensory block level. Thirty patients scheduled for elective cesarean section under combined spinal-epidural anesthesia were randomly allocated into three groups. After intrathecal injection of 0.5% plain bupivacaine 7.5mg, patients in group S were immediately placed in the supine position with left tilt, patients in group L5 were kept lateral for 5 min and then turned to the supine position with left tilt, and patients in group L10 were kept lateral for 10 min and then turned to the supine position with left tilt. At 5 min, median cephalad level of sensory block was lower in groups L5 and L10 compared with group S (corrected Ppostural change from the lateral position to the supine position is an important mechanism enhancing cephalic spread of spinal anesthesia during late pregnancy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. The force applied to successfully turn a foetus during reattempts of external cephalic version is substantially reduced when performed under spinal analgesia.

    Science.gov (United States)

    Suen, Stephen Sik Hung; Khaw, Kim S; Law, Lai Wa; Sahota, Daljit Singh; Lee, Shara Wee Yee; Lau, Tze Kin; Leung, Tak Yeung

    2012-06-01

    To compare the forces exerted during external cephalic version (ECV) on the maternal abdomen between ( 1 ) the primary attempts performed without spinal analgesia (SA), which failed and ( 2 ) the subsequent reattempts performed under SA. Patients with an uncomplicated singleton breech-presenting pregnancy suitable for ECV were recruited. During ECV, the operator wore a pair of gloves, which had thin piezo-resistive pressure sensors measuring the contact pressure between the operator's hands and maternal abdomen. For patients who had failed ECV, reattempts by the same operator was made with patients under SA, and the applied force was measured in the same manner. The profile of the exerted forces over time during each attempt was analyzed and denoted by pressure-time integral (PTI: mmHg sec). Pain score was also graded by patients using visual analogue scale. Both PTI and pain score before and after the use of SA were then compared. Overall, eight patients who had a failed ECV without SA underwent a reattempt with SA. All of them had successful version and the median PTI of the successful attempts under SA were lower than that of the previous failed attempts performed without SA (127 386 mmHg sec vs. 298,424 mmHg sec; p = 0.017). All of them also reported a 0 pain score, which was significantly lower than that of before (median 7.5; p = 0.016). SA improves the success rate of ECV as well as reduces the force required for successful version.

  15. Patients' and professionals' barriers and facilitators to external cephalic version for breech presentation at term, a qualitative analysis in the Netherlands.

    Science.gov (United States)

    Rosman, A N; Vlemmix, F; Fleuren, M A H; Rijnders, M E; Beuckens, A; Opmeer, B C; Mol, B W J; van Zwieten, M C B; Kok, M

    2014-03-01

    external cephalic version (ECV) is a relatively simple and safe manoeuvre and a proven effective approach in the reduction of breech presentation at term. There is professional consensus that ECV should be offered to all women with a fetus in breech presentation, but only up to 70% of women eligible for ECV undergo an ECV attempt. The aim of the study was to identify barriers and facilitators for ECV among professionals and women with a breech presentation at term. qualitative study with semi-structured interviews. Dutch hospitals. pregnant women with a breech presentation who had decided on ECV, and midwives and gynaecologists treating women with a breech presentation. on the basis of national guidelines and expert opinions, we developed topic lists to guide the interviews and discuss barriers and facilitators in order to decide on ECV (pregnant women) or advice on ECV (midwives and gynaecologists). among pregnant women the main barriers were fear, the preference to have a planned caesarean section (CS), incomplete information and having witnessed birth complications within the family or among friends. The main facilitators were the wish for a home birth, the wish for a vaginal delivery and confidence of the safety of ECV. Among professionals the main barriers were a lack of knowledge to fully inform and counsel patients on ECV, and the inability to counsel women who preferred a primary CS. The main facilitator was an unambiguous policy on (counselling for) ECV within the region. we identified several barriers and facilitators possibly explaining the suboptimal implementation of ECV for breech presentation in the Netherlands. This knowledge should be taken into account in designing implementation strategies for ECV to improve the uptake of ECV by professionals and patients. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. A randomized controlled trial of the effect of combined spinal-epidural analgesia on the success of external cephalic version for breech presentation.

    Science.gov (United States)

    Sullivan, J T; Grobman, W A; Bauchat, J R; Scavone, B M; Grouper, S; McCarthy, R J; Wong, C A

    2009-10-01

    Improving the success of external cephalic version (ECV) for breech presentation may help avoid some cesarean deliveries. The results of randomized trials comparing the success of ECV with neuraxial analgesia compared to control are inconsistent. We hypothesized that combined spinal-epidural (CSE) analgesia would increase the success of ECV when compared with systemic opioid analgesia. Parturients with singleton breech presentation (n=96) were randomized to receive CSE analgesia with bupivacaine 2.5mg and fentanyl 15 microg (CSE group) or intravenous fentanyl 50 microg (SYS group) before ECV attempt. The primary outcome was ECV success. The success rate of ECV was 47% with CSE and 31% in the SYS group (P=0.14). Subsequent vaginal delivery was 36% for CSE and 25% for SYS (P=0.27). Median [IQR] visual analog pain scores (0-100mm scale) were lower with CSE (3 [0-12]) compared to SYS analgesia (36 [16 to 54]) (P<0.005) and patient satisfaction (0-10 scale) was higher (CSE 10 [9 to 10] versus SYS 7 [4 to 9]) (P<0.005). There were no differences in fetal heart rate patterns, but median time to return to fetal heart rate reactivity after analgesia was shorter with CSE (13 [IQR 9-21] min) compared to the SYS group (39 [IQR 23-51] min) (P=0.02). There was no difference in the rate of successful ECV or vaginal delivery with CSE compared to intravenous fentanyl analgesia. Pain scores were lower and satisfaction higher with CSE analgesia, and median time to fetal heart rate reactivity was shorter in the CSE group.

  17. The value of three-dimensional photogrammetry in isolated sagittal synostosis: Impact of age and surgical technique on intracranial volume and cephalic index─a retrospective cohort study.

    Science.gov (United States)

    Mertens, Christian; Wessel, Eline; Berger, Moritz; Ristow, Oliver; Hoffmann, Jürgen; Kansy, Katinka; Freudlsperger, Christian; Bächli, Heidrun; Engel, Michael

    2017-12-01

    The aim of this study was to compare the outcome of intracranial volume (ICV) and cephalic index (CI) between two different techniques for surgical therapy of sagittal synostosis. Between 2011 and 2015, all patients scheduled for surgical therapy of sagittal synostosis were consecutively enrolled. All patients younger than 6 months underwent early extended strip craniectomy (ESC group), and patients older than 6 months underwent late modified pi-procedure (MPP group). To measure ICV and CI, data acquisition was performed via three-dimensional photogrammetry, 1 day before (T0) and between 10 and 12 weeks after surgery (T1). Results were compared with an age-matched reference group of healthy children. Perioperative parameters, as duration of surgery and the amount of blood loss of both surgical procedures were analyzed. A total of 85 patients were enrolled. Of the patients, 48 underwent an extended strip craniotomy with parietal osteotomies and biparietal widening and 37 patients underwent a late modified pi-procedure. There was no significant difference between the ESC group and the MPP group regarding the efficacy of improving CI (p > 0.05). Both techniques were able to normalize CI and to improve head shape. ICV was normal compared to age-matched norm-groups with both techniques, pre- and postoperatively. However, duration of the surgical procedure and calculated blood loss were significantly lower in the ESC group (p photogrammetry is a valid method to objectively evaluate patients before and after surgery without exposing pediatric patients to ionizing radiation. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  18. Greater rate of cephalic screw mobilisation following proximal femoral nailing in hip fractures with a tip-apex distance (TAD) and a calcar referenced TAD greater than 25 mm.

    Science.gov (United States)

    Aicale, Rocco; Maffulli, Nicola

    2018-05-02

    To ascertain whether the tip-apex distance (TAD), calcar referenced TAD (CalTAD), and the sum of both (TADcalTAD) are predictive measurements of mobilisation of the cephalic screw in patients with trochanteric hip fractures. Between 2014 and 2015, 68 patients (mean age 86 years, 45 females, 23 males) with a trochanteric hip fracture underwent intramedullary nailing. The TAD and CalTAD were measured, and for each parameter, we calculated sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). There is evidence of a statistically significant association between a TAD and CalTAD greater than 25 mm and a TADcalTAD greater than 50 mm and mobilisation of the cephalic screw. All measurements have similar sensitivity, but the TAD presents the highest specificity (p TAD and CalTAD less than 25 mm and a TADcalTAD less than 50 mm when using intramedullary fixation.

  19. Selective expression of the type 3 isoform of ryanodine receptor Ca2+ release channel (RyR3) in a subset of slow fibers in diaphragm and cephalic muscles of adult rabbits

    International Nuclear Information System (INIS)

    Conti, Antonio; Reggiani, Carlo; Sorrentino, Vincenzo

    2005-01-01

    The expression pattern of the RyR3 isoform of Ca 2+ release channels was analysed by Western blot in neonatal and adult rabbit skeletal muscles. The results obtained show that the expression of the RyR3 isoform is developmentally regulated. In fact, RyR3 expression was detected in all muscles analysed at 2 and 15 days after birth while, in adult animals, it was restricted to a subset of muscles that includes diaphragm, masseter, pterygoideus, digastricus, and tongue. Interestingly, all of these muscles share a common embryonic origin being derived from the somitomeres or from the cephalic region of the embryo. Immunofluorescence analysis of rabbit skeletal muscle cross-sections showed that RyR3 staining was detected in all fibers of neonatal muscles. In contrast, in those adult muscles expressing RyR3 only a fraction of fibers was labelled. Staining of these muscles with antibodies against fast and slow myosins revealed a close correlation between expression of RyR3 and fibers expressing slow myosin isoform

  20. System dynamics

    International Nuclear Information System (INIS)

    Kim, Do Hun; Mun, Tae Hun; Kim, Dong Hwan

    1999-02-01

    This book introduces systems thinking and conceptual tool and modeling tool of dynamics system such as tragedy of single thinking, accessible way of system dynamics, feedback structure and causal loop diagram analysis, basic of system dynamics modeling, causal loop diagram and system dynamics modeling, information delay modeling, discovery and application for policy, modeling of crisis of agricultural and stock breeding products, dynamic model and lesson in ecosystem, development and decadence of cites and innovation of education forward system thinking.

  1. Dynamical Languages

    Science.gov (United States)

    Xie, Huimin

    The following sections are included: * Definition of Dynamical Languages * Distinct Excluded Blocks * Definition and Properties * L and L″ in Chomsky Hierarchy * A Natural Equivalence Relation * Symbolic Flows * Symbolic Flows and Dynamical Languages * Subshifts of Finite Type * Sofic Systems * Graphs and Dynamical Languages * Graphs and Shannon-Graphs * Transitive Languages * Topological Entropy

  2. Semiclassical dynamics

    International Nuclear Information System (INIS)

    Balazs, N.L.

    1979-01-01

    It is pointed out that in semiclassical dynamics one is encouraged to study the evolution of those curves in phase space which classically represent ensembles corresponding to wave functions. It is shown that the fixed points generate new time scales so that for times longer than the critical times, quantum dynamics will profoundly differ from classical dynamics. (P.L.)

  3. Discrete dynamics versus analytic dynamics

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2014-01-01

    For discrete classical Molecular dynamics obtained by the “Verlet” algorithm (VA) with the time increment h there exists a shadow Hamiltonian H˜ with energy E˜(h) , for which the discrete particle positions lie on the analytic trajectories for H˜ . Here, we proof that there, independent...... of such an analytic analogy, exists an exact hidden energy invariance E * for VA dynamics. The fact that the discrete VA dynamics has the same invariances as Newtonian dynamics raises the question, which of the formulations that are correct, or alternatively, the most appropriate formulation of classical dynamics....... In this context the relation between the discrete VA dynamics and the (general) discrete dynamics investigated by Lee [Phys. Lett. B122, 217 (1983)] is presented and discussed....

  4. Dynamics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Dynamics Lab replicates vibration environments for every Navy platform. Testing performed includes: Flight Clearance, Component Improvement, Qualification, Life...

  5. Dynamical systems

    CERN Document Server

    Sternberg, Shlomo

    2010-01-01

    Celebrated mathematician Shlomo Sternberg, a pioneer in the field of dynamical systems, created this modern one-semester introduction to the subject for his classes at Harvard University. Its wide-ranging treatment covers one-dimensional dynamics, differential equations, random walks, iterated function systems, symbolic dynamics, and Markov chains. Supplementary materials offer a variety of online components, including PowerPoint lecture slides for professors and MATLAB exercises.""Even though there are many dynamical systems books on the market, this book is bound to become a classic. The the

  6. Dynamic Capabilities

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Stenger, Marianne

    2013-01-01

    The findings reveal a positive relationship between dynamic capabilities and innovation performance in the case enterprises, as we would expect. It was, however, not possible to establish a positive relationship between innovation performance and profitability. Nor was there any positive...... relationship between dynamic capabilities and profitability....

  7. Jumping Dynamics

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2013-01-01

    paradigm the physical scale and henceforth also the massive spectrum of the theory jump at the lower boundary of the conformal window. In particular we propose that a theory can suddenly jump from a Quantum Chromodynamics type spectrum, at the lower boundary of the conformal window, to a conformal one...... without particle interpretation. The jumping scenario, therefore, does not support a near-conformal dynamics of walking type. We will also discuss the impact of jumping dynamics on the construction of models of dynamical electroweak symmetry breaking....

  8. Galactic dynamics

    CERN Document Server

    Binney, James

    2008-01-01

    Since it was first published in 1987, Galactic Dynamics has become the most widely used advanced textbook on the structure and dynamics of galaxies and one of the most cited references in astrophysics. Now, in this extensively revised and updated edition, James Binney and Scott Tremaine describe the dramatic recent advances in this subject, making Galactic Dynamics the most authoritative introduction to galactic astrophysics available to advanced undergraduate students, graduate students, and researchers. Every part of the book has been thoroughly overhauled, and many section

  9. Space dynamics

    International Nuclear Information System (INIS)

    Corno, S.E.

    1995-01-01

    Analytical methods for Space Dynamics of fission reactors, are presented. It is shown how a few sample problems in space dynamics can be solved, within the one and two group diffusion model, by purely analytical tools, essentially based on Laplace transform and complex Green function techniques. A quite suggestive generalization of this approach, applicable to the fluid core reactors, whose fuel is undergoing a violent mixing, is reported and briefly discussed. (author)

  10. Structural Dynamics

    International Nuclear Information System (INIS)

    Kim, Du Gi

    2005-08-01

    This book introduces summary of structural dynamics, the reason of learning of structural dynamics, single-degree of freedom system, simple harmonic vibration and application, numerical analysis method, such as time domain and frequency domain and nonlinear system, multi-degree of freedom system random vibration over discrete distribution, continuous distribution and extreme value distribution, circumstance vibration, earth quake vibration, including input earthquake, and earthquake-resistant design and capacity spectrum method, wind oscillation wave vibration, vibration control and maintenance control.

  11. Dynamic Bifurcations

    CERN Document Server

    1991-01-01

    Dynamical Bifurcation Theory is concerned with the phenomena that occur in one parameter families of dynamical systems (usually ordinary differential equations), when the parameter is a slowly varying function of time. During the last decade these phenomena were observed and studied by many mathematicians, both pure and applied, from eastern and western countries, using classical and nonstandard analysis. It is the purpose of this book to give an account of these developments. The first paper, by C. Lobry, is an introduction: the reader will find here an explanation of the problems and some easy examples; this paper also explains the role of each of the other paper within the volume and their relationship to one another. CONTENTS: C. Lobry: Dynamic Bifurcations.- T. Erneux, E.L. Reiss, L.J. Holden, M. Georgiou: Slow Passage through Bifurcation and Limit Points. Asymptotic Theory and Applications.- M. Canalis-Durand: Formal Expansion of van der Pol Equation Canard Solutions are Gevrey.- V. Gautheron, E. Isambe...

  12. Dynamic Pricing

    DEFF Research Database (Denmark)

    Sharifi, Reza; Anvari-Moghaddam, Amjad; Fathi, S. Hamid

    2017-01-01

    Dynamic pricing scheme, also known as real-time pricing (RTP), can be more efficient and technically beneficial than the other price-based schemes (such as flat-rate or time-of-use (TOU) pricing) for enabling demand response (DR) actions. Over the past few years, advantages of RTP-based schemes h...... of dynamic pricing can lead to increased willingness of consumers to participate in DR programs which in turn improve the operation of liberalized electricity markets.......Dynamic pricing scheme, also known as real-time pricing (RTP), can be more efficient and technically beneficial than the other price-based schemes (such as flat-rate or time-of-use (TOU) pricing) for enabling demand response (DR) actions. Over the past few years, advantages of RTP-based schemes...

  13. Record dynamics

    DEFF Research Database (Denmark)

    Robe, Dominic M.; Boettcher, Stefan; Sibani, Paolo

    2016-01-01

    When quenched rapidly beyond their glass transition, colloidal suspensions fall out of equilibrium. The pace of their dynamics then slows down with the system age, i.e., with the time elapsed after the quench. This breaking of time translational invariance is associated with dynamical observables...... which depend on two time-arguments. The phenomenology is shared by a broad class of aging systems and calls for an equally broad theoretical description. The key idea is that, independent of microscopic details, aging systems progress through rare intermittent structural relaxations that are de......-facto irreversible and become increasingly harder to achieve. Thus, a progression of record-sized dynamical barriers are traversed in the approach to equilibration. Accordingly, the statistics of the events is closely described by a log-Poisson process. Originally developed for relaxation in spin glasses...

  14. Dynamical systems

    CERN Document Server

    Birkhoff, George D

    1927-01-01

    His research in dynamics constitutes the middle period of Birkhoff's scientific career, that of maturity and greatest power. -Yearbook of the American Philosophical Society The author's great book€¦is well known to all, and the diverse active modern developments in mathematics which have been inspired by this volume bear the most eloquent testimony to its quality and influence. -Zentralblatt MATH In 1927, G. D. Birkhoff wrote a remarkable treatise on the theory of dynamical systems that would inspire many later mathematicians to do great work. To a large extent, Birkhoff was writing about his o

  15. Glassy Dynamics

    DEFF Research Database (Denmark)

    Jensen, Henrik J.; Sibani, Paolo

    2007-01-01

    The term glassy dynamics is often used to refer to the extremely slow relaxation observed in several types of many component systems. The time span needed to reach a steady, time independent, state will typically be far beyond experimentally accessible time scales. When melted alloys are cooled...... down they typically do not enter a crystalline ordered state. Instead the atoms retain the amorphous arrangement characteristic of the liquid high temperature phase while the mobility of the molecules decreases very many orders of magnitude. This colossal change in the characteristic dynamical time...

  16. Forest dynamics.

    Science.gov (United States)

    Frelich, Lee

    2016-01-01

    Forest dynamics encompass changes in stand structure, species composition, and species interactions with disturbance and environment over a range of spatial and temporal scales. For convenience, spatial scale is defined as individual tree, neighborhood, stand, and landscape. Whether a given canopy-leveling disturbance will initiate a sequence of development in structure with little change in composition or initiate an episode of succession depends on a match or mismatch, respectively, with traits of the dominant tree species that allow the species to survive disturbance. When these match, certain species-disturbance type combinations lock in a pattern of stand and landscape dynamics that can persist for several generations of trees; thus, dominant tree species regulate, as well as respond to, disturbance. A complex interaction among tree species, neighborhood effects, disturbance type and severity, landform, and soils determines how stands of differing composition form and the mosaic of stands that compose the landscape. Neighborhood effects (e.g., serotinous seed rain, sprouting, shading, leaf-litter chemistry, and leaf-litter physical properties) operate at small spatial extents of the individual tree and its neighbors but play a central role in forest dynamics by contributing to patch formation at stand scales and dynamics of the entire landscape. Dominance by tree species with neutral to negative neighborhood effects leads to unstable landscape dynamics in disturbance-prone regions, wherein most stands are undergoing succession; stability can only occur under very low-severity disturbance regimes. Dominance by species with positive effects leads to stable landscape dynamics wherein only a small proportion of stands undergo succession at any one time. Positive neighborhood effects are common in temperate and boreal zones, whereas negative effects are more common in tropical climates. Landscapes with positive dynamics have alternate categories of dynamics

  17. Classical dynamics

    CERN Document Server

    Greenwood, Donald T

    1997-01-01

    Graduate-level text for science and technology students provides strong background in the more abstract and intellectually satisfying areas of dynamical theory. Topics include d'Alembert's principle and the idea of virtual work, Hamilton's equations, Hamilton-Jacobi theory, canonical transformations, more. Problems and references at chapter ends.

  18. Expansion dynamics

    International Nuclear Information System (INIS)

    Knoll, J.

    1985-10-01

    A quantum dynamical model is suggested which describes the expansion and disassembly phase of highly excited compounds formed in energetic heavy-ion collisions. First applications in two space and one time dimensional model world are discussed and qualitatively compared to standard freeze-out concepts. (orig.)

  19. Membrane dynamics

    DEFF Research Database (Denmark)

    Bendix, Pól Martin

    2015-01-01

    Current topics include membrane-protein interactions with regard to membrane deformation or curvature sensing by BAR domains. Also, we study the dynamics of membrane tubes of both cells and simple model membrane tubes. Finally, we study membrane phase behavior which has important implications...... for the lateral organization of membranes as wells as for physical properties like bending, permeability and elasticity...

  20. Random dynamics

    International Nuclear Information System (INIS)

    Bennett, D.L.; Brene, N.; Nielsen, H.B.

    1986-06-01

    The goal of random dynamics is the derivation of the laws of Nature as we know them (standard model) from inessential assumptions. The inessential assumptions made here are expressed as sets of general models at extremely high energies: gauge glass and spacetime foam. Both sets of models lead tentatively to the standard model. (orig.)

  1. Dynamic LIMIDS

    NARCIS (Netherlands)

    Díez, F.J.; Gerven, M.A.J. van; Sucar, L.E.; Morales, E.F.; Hoey, J.

    2011-01-01

    One of the objectives of artificial intelligence is to build decision-support models for systems that evolve over time and include several types of uncertainty. Dynamic limited-memory influence diagrams (DLIMIDs) are a new type of model proposed recently for this kind of problems. DLIMIDs are

  2. System Dynamics

    Science.gov (United States)

    Morecroft, John

    System dynamics is an approach for thinking about and simulating situations and organisations of all kinds and sizes by visualising how the elements fit together, interact and change over time. This chapter, written by John Morecroft, describes modern system dynamics which retains the fundamentals developed in the 1950s by Jay W. Forrester of the MIT Sloan School of Management. It looks at feedback loops and time delays that affect system behaviour in a non-linear way, and illustrates how dynamic behaviour depends upon feedback loop structures. It also recognises improvements as part of the ongoing process of managing a situation in order to achieve goals. Significantly it recognises the importance of context, and practitioner skills. Feedback systems thinking views problems and solutions as being intertwined. The main concepts and tools: feedback structure and behaviour, causal loop diagrams, dynamics, are practically illustrated in a wide variety of contexts from a hot water shower through to a symphony orchestra and the practical application of the approach is described through several real examples of its use for strategic planning and evaluation.

  3. Coastal Dynamics

    NARCIS (Netherlands)

    Roelvink, J.A.; Steetzel, H.J.; Bliek, A.; Rakhorst, H.D.; Roelse, P.; Bakker, W.T.

    1998-01-01

    This book deals on "Coastal Dynamics", which will be defined in a narrow sense as a mathematical theory, which starts from given equations of motion for the sediment, which leads with the continuity equation and given boundary conditions to a calculated (eventually schematized) coastal topography,

  4. Structural dynamics

    CERN Document Server

    Strømmen, Einar N

    2014-01-01

    This book introduces to the theory of structural dynamics, with focus on civil engineering structures that may be described by line-like beam or beam-column type of systems, or by a system of rectangular plates. Throughout this book the mathematical presentation contains a classical analytical description as well as a description in a discrete finite element format, covering the mathematical development from basic assumptions to the final equations ready for practical dynamic response predictions. Solutions are presented in time domain as well as in frequency domain. Structural Dynamics starts off at a basic level and step by step brings the reader up to a level where the necessary safety considerations to wind or horizontal ground motion induced dynamic design problems can be performed. The special theory of the tuned mass damper has been given a comprehensive treatment, as this is a theory not fully covered elsewhere. For the same reason a chapter on the problem of moving loads on beams has been included.

  5. Random dynamics

    International Nuclear Information System (INIS)

    Bennett, D.L.

    1987-01-01

    The goal of random dynamics is the derivation of the laws of Nature as we know them (standard model) from inessential assumptions. The inessential assumptions made here are expressed as sets of general models at extremely high energies: Gauge glass and spacetime foam. Both sets of models lead tentatively to the standard model. (orig.)

  6. Random Dynamics

    Science.gov (United States)

    Bennett, D. L.; Brene, N.; Nielsen, H. B.

    1987-01-01

    The goal of random dynamics is the derivation of the laws of Nature as we know them (standard model) from inessential assumptions. The inessential assumptions made here are expressed as sets of general models at extremely high energies: gauge glass and spacetime foam. Both sets of models lead tentatively to the standard model.

  7. Applied dynamics

    CERN Document Server

    Schiehlen, Werner

    2014-01-01

    Applied Dynamics is an important branch of engineering mechanics widely applied to mechanical and automotive engineering, aerospace and biomechanics as well as control engineering and mechatronics. The computational methods presented are based on common fundamentals. For this purpose analytical mechanics turns out to be very useful where D’Alembert’s principle in the Lagrangian formulation proves to be most efficient. The method of multibody systems, finite element systems and continuous systems are treated consistently. Thus, students get a much better understanding of dynamical phenomena, and engineers in design and development departments using computer codes may check the results more easily by choosing models of different complexity for vibration and stress analysis.

  8. Delta Dynamics

    DEFF Research Database (Denmark)

    Bendixen, Mette

    . The warming air temperature affects the soil temperature and permafrost thaws and destabilizes the material in the coastal zone. In Greenland, the warming temperature lowers the surface mass balance of the Greenland Ice Sheet and more material is transported to the coastal zone. The sea ice extent is thinning...... of a fjord and the second type is a wider fan-shaped open delta. Most deltas are directly coupled to the Greenland Ice Sheet or local icecaps and are highly influenced by the dynamics in the catchments. It is demonstrated how a modern changing climate directly affects delta dynamics, and that Greenlandic...... deltas are prograding, contrary to the global trend showing eroding Arctic coasts. Moreover, it is revealed that the increasing proglacial freshwater runoff, caused by a lowering of the surface mass balance of the Greenland Ice Sheet is the main determining agent in delta progradation. The final part...

  9. Fluid dynamics

    CERN Document Server

    Bernard, Peter S

    2015-01-01

    This book presents a focused, readable account of the principal physical and mathematical ideas at the heart of fluid dynamics. Graduate students in engineering, applied math, and physics who are taking their first graduate course in fluids will find this book invaluable in providing the background in physics and mathematics necessary to pursue advanced study. The book includes a detailed derivation of the Navier-Stokes and energy equations, followed by many examples of their use in studying the dynamics of fluid flows. Modern tensor analysis is used to simplify the mathematical derivations, thus allowing a clearer view of the physics. Peter Bernard also covers the motivation behind many fundamental concepts such as Bernoulli's equation and the stream function. Many exercises are designed with a view toward using MATLAB or its equivalent to simplify and extend the analysis of fluid motion including developing flow simulations based on techniques described in the book.

  10. Superconductor Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Gömöry, F [Bratislava, Inst. Elect. Eng. (Slovakia)

    2014-07-01

    Superconductors used in magnet technology could carry extreme currents because of their ability to keep the magnetic flux motionless. The dynamics of the magnetic flux interaction with superconductors is controlled by this property. The cases of electrical transport in a round wire and the magnetization of wires of various shapes (circular, elliptical, plate) in an external magnetic field are analysed. Resistance to the magnetic field penetration means that the field produced by the superconducting magnet is no longer proportional to the supplied current. It also leads to a dissipation of electromagnetic energy. In conductors with unequal transverse dimensions, such as flat cables, the orientation with respect to the magnetic field plays an essential role. A reduction of magnetization currents can be achieved by splitting the core of a superconducting wire into fine filaments; however, new kinds of electrical currents that couple the filaments consequently appear. Basic formulas allowing qualitative analyses of various flux dynamic cases are presented.

  11. Beam dynamics

    International Nuclear Information System (INIS)

    Abell, D; Adelmann, A; Amundson, J; Dragt, A; Mottershead, C; Neri, F; Pogorelov, I; Qiang, J; Ryne, R; Shalf, J; Siegerist, C; Spentzouris, P; Stern, E; Venturini, M; Walstrom, P

    2006-01-01

    We describe some of the accomplishments of the Beam Dynamics portion of the SciDAC Accelerator Science and Technology project. During the course of the project, our beam dynamics software has evolved from the era of different codes for each physical effect to the era of hybrid codes combining start-of-the-art implementations for multiple physical effects to the beginning of the era of true multi-physics frameworks. We describe some of the infrastructure that has been developed over the course of the project and advanced features of the most recent developments, the interplay betwen beam studies and simulations and applications to current machines at Fermilab. Finally we discuss current and future plans for simulations of the International Linear Collider

  12. Hamiltonian dynamics

    CERN Document Server

    Vilasi, Gaetano

    2001-01-01

    This is both a textbook and a monograph. It is partially based on a two-semester course, held by the author for third-year students in physics and mathematics at the University of Salerno, on analytical mechanics, differential geometry, symplectic manifolds and integrable systems. As a textbook, it provides a systematic and self-consistent formulation of Hamiltonian dynamics both in a rigorous coordinate language and in the modern language of differential geometry. It also presents powerful mathematical methods of theoretical physics, especially in gauge theories and general relativity. As a m

  13. Complex dynamics

    CERN Document Server

    Carleson, Lennart

    1993-01-01

    Complex dynamics is today very much a focus of interest. Though several fine expository articles were available, by P. Blanchard and by M. Yu. Lyubich in particular, until recently there was no single source where students could find the material with proofs. For anyone in our position, gathering and organizing the material required a great deal of work going through preprints and papers and in some cases even finding a proof. We hope that the results of our efforts will be of help to others who plan to learn about complex dynamics and perhaps even lecture. Meanwhile books in the field a. re beginning to appear. The Stony Brook course notes of J. Milnor were particularly welcome and useful. Still we hope that our special emphasis on the analytic side will satisfy a need. This book is a revised and expanded version of notes based on lectures of the first author at UCLA over several \\Vinter Quarters, particularly 1986 and 1990. We owe Chris Bishop a great deal of gratitude for supervising the production of cour...

  14. Injerto columelar extendido angulado. Método para prevenir la rotación cefálica y lateral de los injertos de cartílago en la punta nasal Angulated extended collumelar graft. A method to prevent the cephalic and lateral rotation of the cartilage graft in the nasal tip

    Directory of Open Access Journals (Sweden)

    Y. Castro Govea

    2011-06-01

    Full Text Available El paciente mestizo generalmente posee una nariz pequeña, de base ancha, con fosas nasales redondas y dorso convexo. Los cartílagos alares son débiles, delgados y cortos, proporcionando un soporte estructural deficiente y pobre definición de la punta nasal. Los injertos de cartílago de la punta nasal se usan frecuentemente para corregir esta condición; sin embargo un problema común es la rotación cefálica, caudal y lateral de estos cartílagos. Empleamos un injerto columelar extendido angulado (ICEA para proporcionar elongación y soporte columelar; la extensión angulada nos brinda a su vez un mejor control y predicción de la posición de los injertos de la punta nasal al prevenir su desplazamiento cefálico y lateral. El protocolo quirúrgico empleado incluyó historia clínica completa, desarrollo de un plan quirúrgico mediante análisis de la deformidad y fotografías pre y postoperatorias para el control de los pacientes a medio y largo plazo. Tratamos 95 pacientes usando este procedimiento; 75 con rinoplastia abierta y 20 con técnica cerrada. El rango del periodo de seguimiento fue de 6 meses a 4 años. Los resultados obtenidos fueron satisfactorios, mostrando mejor control y predicción de la forma de la punta nasal. En conclusión, creemos que el injerto columelar extendido angulado proporciona un mejor control de la proyección y angularidad de los injertos colocados en la punta nasal.The mestizo patient usually has a small nose, with wide base, round nostrils and convex dorsum. The alar cartilages are weak, thin and short, providing a deficient structural support and poor definition of the nasal tip. Cartilage graft in the nasal tip are very often used to correct this condition, but a commun problem of this procedure is the cephalic or lateral rotation of these grafts. We used an angulated extended collumalar graft to give collumelar support and elongation. The angulated extension of the graft provides a better control and

  15. Population dynamics

    Directory of Open Access Journals (Sweden)

    Cooch, E. G.

    2004-06-01

    Full Text Available Increases or decreases in the size of populations over space and time are, arguably, the motivation for much of pure and applied ecological research. The fundamental model for the dynamics of any population is straightforward: the net change over time in the abundance of some population is the simple difference between the number of additions (individuals entering the population minus the number of subtractions (individuals leaving the population. Of course, the precise nature of the pattern and process of these additions and subtractions is often complex, and population biology is often replete with fairly dense mathematical representations of both processes. While there is no doubt that analysis of such abstract descriptions of populations has been of considerable value in advancing our, there has often existed a palpable discomfort when the ‘beautiful math’ is faced with the often ‘ugly realities’ of empirical data. In some cases, this attempted merger is abandoned altogether, because of the paucity of ‘good empirical data’ with which the theoretician can modify and evaluate more conceptually–based models. In some cases, the lack of ‘data’ is more accurately represented as a lack of robust estimates of one or more parameters. It is in this arena that methods developed to analyze multiple encounter data from individually marked organisms has seen perhaps the greatest advances. These methods have rapidly evolved to facilitate not only estimation of one or more vital rates, critical to population modeling and analysis, but also to allow for direct estimation of both the dynamics of populations (e.g., Pradel, 1996, and factors influencing those dynamics (e.g., Nichols et al., 2000. The interconnections between the various vital rates, their estimation, and incorporation into models, was the general subject of our plenary presentation by Hal Caswell (Caswell & Fujiwara, 2004. Caswell notes that although interest has traditionally

  16. Bile dynamics

    International Nuclear Information System (INIS)

    Harding, L.K.; Donovan, I.A.

    1986-01-01

    The availability of new biliary radiopharamaceutical led to the expectation that the physiology and the pathophysiology of bile would be resolved. Some aspects of the physiology of bile have clarified and it has been shown that nasogastric intubation does not cause bile reflux. Careful analysis of excretion patterns has allowed detection of obstruction of the bile duct after cholecystectomy, and the radiopharmaceuticals have proved helpful in the diagnosis of acute colecystitis. In chronic cholecystitis, however, varying results have been obtained. Information on the incidence and amount of reflux in normal subjects is also confused, since several different techniques have been used with widely varying results. The clinical value of biliary dynamic studies is at present limited in patients with chronic cholecystitis, peptic ulcer, or symptoms suggestive of bile reflux. More data, with appropriate control subjects, is required to identify abnormal reflux, determine its effects, and decide on appropriate treatment

  17. Group dynamics.

    Science.gov (United States)

    Scandiffio, A L

    1990-12-01

    Group dynamics play a significant role within any organization, culture, or unit. The important thing to remember with any of these structures is that they are made up of people--people with different ideas, motivations, background, and sometimes different agendas. Most groups, formal or informal, look for a leader in an effort to maintain cohesiveness of the unit. At times, that cultural bond must be developed; once developed, it must be nurtured. There are also times that one of the group no longer finds the culture comfortable and begins to act out behaviorally. It is these times that become trying for the leader as she or he attempts to remain objective when that which was once in the building phase of group cohesiveness starts to fall apart. At all times, the manager must continue to view the employee creating the disturbance as an integral part of the group. It is at this time that it is beneficial to perceive the employee exhibiting problem behaviors as a special employee, as one who needs the benefit of your experience and skills, as one who is still part of the group. It is also during this time that the manager should focus upon her or his own views in the area of power, communication, and the corporate culture of the unit that one has established before attempting to understand another's point of view. Once we understand our own motivation and accept ourselves, it is then that we may move on to offer assistance to another. Once we understand our insecurities recognizing staff dysfunction as a symptom of system dysfunction will not be so threatening to the concept of the manager that we perceive ourselves to be. It takes a secure person to admit that she or he favors staff before deciding to do something to change things. The important thing to know is that it can be done. The favored staff can find a new way of relating to others, the special employee can find new modes of behavior (and even find self-esteem in the process), the group can find new ways

  18. Fluid dynamics

    CERN Document Server

    Ruban, Anatoly I

    This is the first book in a four-part series designed to give a comprehensive and coherent description of Fluid Dynamics, starting with chapters on classical theory suitable for an introductory undergraduate lecture course, and then progressing through more advanced material up to the level of modern research in the field. The present Part 1 consists of four chapters. Chapter 1 begins with a discussion of Continuum Hypothesis, which is followed by an introduction to macroscopic functions, the velocity vector, pressure, density, and enthalpy. We then analyse the forces acting inside a fluid, and deduce the Navier-Stokes equations for incompressible and compressible fluids in Cartesian and curvilinear coordinates. In Chapter 2 we study the properties of a number of flows that are presented by the so-called exact solutions of the Navier-Stokes equations, including the Couette flow between two parallel plates, Hagen-Poiseuille flow through a pipe, and Karman flow above an infinite rotating disk. Chapter 3 is d...

  19. Internet dynamics

    Science.gov (United States)

    Lukose, Rajan Mathew

    The World Wide Web and the Internet are rapidly expanding spaces, of great economic and social significance, which offer an opportunity to study many phenomena, often previously inaccessible, on an unprecedented scale and resolution with relative ease. These phenomena are measurable on the scale of tens of millions of users and hundreds of millions of pages. By virtue of nearly complete electronic mediation, it is possible in principle to observe the time and ``spatial'' evolution of nearly all choices and interactions. This cyber-space therefore provides a view into a number of traditional research questions (from many academic disciplines) and creates its own new phenomena accessible for study. Despite its largely self-organized and dynamic nature, a number of robust quantitative regularities are found in the aggregate statistics of interesting and useful quantities. These regularities can be understood with the help of models that draw on ideas from statistical physics as well as other fields such as economics, psychology and decision theory. This thesis develops models that can account for regularities found in the statistics of Internet congestion and user surfing patterns and discusses some practical consequences. practical consequences.

  20. Relativistic stellar dynamics

    International Nuclear Information System (INIS)

    Contopoulos, G.

    1983-01-01

    In this paper, three main areas of relativistic stellar dynamics are reviewed: (a) The dynamics of clusters, or nuclei of galaxies, of very high density; (b) The dynamics of systems containing a massive black hole; and (c) The dynamics of particles (and photons) in an expanding Universe. The emphasis is on the use of orbit perturbations. (Auth.)

  1. Principles of magnetoplasma dynamics

    International Nuclear Information System (INIS)

    Woods, L.C.

    1987-01-01

    A self-contained account is given of magnetoplasma dynamics covering fluid dynamics, thermodynamics, kinetic theory of gases, particle dynamics and electromagnetism. The six chapter headings are, basic concepts, magnetohydrodynamics, dynamics of charged particles, transport in a magnetoplasma, magnetoplasma shock waves, and transport in tokamaks. There are 231 references. (U.K.)

  2. Fundamentals of structural dynamics

    CERN Document Server

    Craig, Roy R

    2006-01-01

    From theory and fundamentals to the latest advances in computational and experimental modal analysis, this is the definitive, updated reference on structural dynamics.This edition updates Professor Craig's classic introduction to structural dynamics, which has been an invaluable resource for practicing engineers and a textbook for undergraduate and graduate courses in vibrations and/or structural dynamics. Along with comprehensive coverage of structural dynamics fundamentals, finite-element-based computational methods, and dynamic testing methods, this Second Edition includes new and e

  3. Dynamic light scattering. Observation of polymer dynamics

    International Nuclear Information System (INIS)

    Hiroi, Takashi

    2015-01-01

    Dynamic light scattering is a technique to measure properties of polymer solutions such as size distribution. Principle of dynamic light scattering is briefly explained. Sometime dynamic light scattering is regarded as the observation of Doppler shift of scattered light. First, the difficulty for the direct observation of this Doppler shift is mentioned. Then the measurement by using a time correlation function is introduced. Measuring techniques for dynamic light scattering are also introduced. In addition to homodyne and heterodyne detection techniques, the technique called partial heterodyne method is also introduced. This technique is useful for the analysis of nonergodic medium such as polymer gels. Then the application of this technique to condensed suspension is briefly reviewed. As one of the examples, a dynamic light scattering microscope is introduced. By using this apparatus, we can measure the concentration dependence of the size distribution of polymer solutions. (author)

  4. Prediction models for successful external cephalic version: a systematic review.

    Science.gov (United States)

    Velzel, Joost; de Hundt, Marcella; Mulder, Frederique M; Molkenboer, Jan F M; Van der Post, Joris A M; Mol, Ben W; Kok, Marjolein

    2015-12-01

    To provide an overview of existing prediction models for successful ECV, and to assess their quality, development and performance. We searched MEDLINE, EMBASE and the Cochrane Library to identify all articles reporting on prediction models for successful ECV published from inception to January 2015. We extracted information on study design, sample size, model-building strategies and validation. We evaluated the phases of model development and summarized their performance in terms of discrimination, calibration and clinical usefulness. We collected different predictor variables together with their defined significance, in order to identify important predictor variables for successful ECV. We identified eight articles reporting on seven prediction models. All models were subjected to internal validation. Only one model was also validated in an external cohort. Two prediction models had a low overall risk of bias, of which only one showed promising predictive performance at internal validation. This model also completed the phase of external validation. For none of the models their impact on clinical practice was evaluated. The most important predictor variables for successful ECV described in the selected articles were parity, placental location, breech engagement and the fetal head being palpable. One model was assessed using discrimination and calibration using internal (AUC 0.71) and external validation (AUC 0.64), while two other models were assessed with discrimination and calibration, respectively. We found one prediction model for breech presentation that was validated in an external cohort and had acceptable predictive performance. This model should be used to council women considering ECV. Copyright © 2015. Published by Elsevier Ireland Ltd.

  5. Cephalic morphology in the Cavall Pirinenc Català breed

    OpenAIRE

    Parés Casanova, Pere-Miquel

    2009-01-01

    Thirty-five metric parameters were taken on 19 skulls belonging to adult Cavall Pirinenc Català horse breed and were subjected to a Principal Component Analysis. Parameters related with neurocranium width, ventral lengths and those related with ocular orbit are poorly discriminants. On the other hand, parameters related with viscerocranium are strongly discriminant. Our study strengths the importance in using parameters linked to viscerocranium, and frontal length, in equine racial studies on...

  6. Prediction models for successful external cephalic version: a systematic review

    NARCIS (Netherlands)

    Velzel, Joost; de Hundt, Marcella; Mulder, Frederique M.; Molkenboer, Jan F. M.; van der Post, Joris A. M.; Mol, Ben W.; Kok, Marjolein

    2015-01-01

    To provide an overview of existing prediction models for successful ECV, and to assess their quality, development and performance. We searched MEDLINE, EMBASE and the Cochrane Library to identify all articles reporting on prediction models for successful ECV published from inception to January 2015.

  7. The brain of the horse: weight and cephalization quotients.

    Science.gov (United States)

    Cozzi, Bruno; Povinelli, Michele; Ballarin, Cristina; Granato, Alberto

    2014-01-01

    The horse is a common domestic animal whose anatomy has been studied since the XVI century. However, a modern neuroanatomy of this species does not exist and most of the data utilized in textbooks and reviews derive from single specimens or relatively old literature. Here, we report information on the brain of Equus caballus obtained by sampling 131 horses, including brain weight (as a whole and subdivided into its constituents), encephalization quotient (EQ), and cerebellar quotient (CQ), and comparisons with what is known about other relevant species. The mean weight of the fresh brains in our experimental series was 598.63 g (SEM ± 7.65), with a mean body weight of 514.12 kg (SEM ± 15.42). The EQ was 0.78 and the CQ was 0.841. The data we obtained indicate that the horse possesses a large, convoluted brain, with a weight similar to that of other hoofed species of like mass. However, the shape of the brain, the noteworthy folding of the neocortex, and the peculiar longitudinal distribution of the gyri suggest an evolutionary specificity at least partially separate from that of the Cetartiodactyla (even-toed mammals and cetaceans) with whom Perissodactyla (odd-toed mammals) are often grouped.

  8. Morphological changes in the cephalic salivary glands of females ...

    Indian Academy of Sciences (India)

    Prakash

    São Paulo State University (UNESP), Department of Biology, Institute of Biosciences Av. 24A, no.1515, Bela Vista, .... brain. The alveoli are mainly piriform and the ducts wide and flattened (figure 1D, E and F). ... This paper describes the morphological differences .... glands is species-specific and produces a sexual marking.

  9. Dynamic statistical information theory

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In recent years we extended Shannon static statistical information theory to dynamic processes and established a Shannon dynamic statistical information theory, whose core is the evolution law of dynamic entropy and dynamic information. We also proposed a corresponding Boltzmman dynamic statistical information theory. Based on the fact that the state variable evolution equation of respective dynamic systems, i.e. Fokker-Planck equation and Liouville diffusion equation can be regarded as their information symbol evolution equation, we derived the nonlinear evolution equations of Shannon dynamic entropy density and dynamic information density and the nonlinear evolution equations of Boltzmann dynamic entropy density and dynamic information density, that describe respectively the evolution law of dynamic entropy and dynamic information. The evolution equations of these two kinds of dynamic entropies and dynamic informations show in unison that the time rate of change of dynamic entropy densities is caused by their drift, diffusion and production in state variable space inside the systems and coordinate space in the transmission processes; and that the time rate of change of dynamic information densities originates from their drift, diffusion and dissipation in state variable space inside the systems and coordinate space in the transmission processes. Entropy and information have been combined with the state and its law of motion of the systems. Furthermore we presented the formulas of two kinds of entropy production rates and information dissipation rates, the expressions of two kinds of drift information flows and diffusion information flows. We proved that two kinds of information dissipation rates (or the decrease rates of the total information) were equal to their corresponding entropy production rates (or the increase rates of the total entropy) in the same dynamic system. We obtained the formulas of two kinds of dynamic mutual informations and dynamic channel

  10. Structure, Reactivity and Dynamics

    Indian Academy of Sciences (India)

    Understanding structure, reactivity and dynamics is the core issue in chemical ... functional theory (DFT) calculations, molecular dynamics (MD) simulations, light- ... between water and protein oxygen atoms, the superionic conductors which ...

  11. Modeling dynamic swarms

    KAUST Repository

    Ghanem, Bernard; Ahuja, Narendra

    2013-01-01

    This paper proposes the problem of modeling video sequences of dynamic swarms (DSs). We define a DS as a large layout of stochastically repetitive spatial configurations of dynamic objects (swarm elements) whose motions exhibit local spatiotemporal

  12. Spaces of Dynamical Systems

    CERN Document Server

    Pilyugin, Sergei Yu

    2012-01-01

    Dynamical systems are abundant in theoretical physics and engineering. Their understanding, with sufficient mathematical rigor, is vital to solving many problems. This work conveys the modern theory of dynamical systems in a didactically developed fashion.In addition to topological dynamics, structural stability and chaotic dynamics, also generic properties and pseudotrajectories are covered, as well as nonlinearity. The author is an experienced book writer and his work is based on years of teaching.

  13. Dynamics of Media Attention

    NARCIS (Netherlands)

    Traag, V.A.; Reinanda, R.; Hicks, J.; van Klinken, G.; Aziz-Alaoui, M.A.; Bertelle, C.; Liu, X.; Olivier, D.

    2014-01-01

    Studies of human attention dynamics analyses how attention is focused on specific topics, issues or people. In online social media, there are clear signs of exogenous shocks, bursty dynamics, and an exponential or powerlaw lifetime distribution. We here analyse the attention dynamics of traditional

  14. Intramolecular and nonlinear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.J. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

  15. PREFACE: Dynamics of wetting Dynamics of wetting

    Science.gov (United States)

    Grest, Gary S.; Oshanin, Gleb; Webb, Edmund B., III

    2009-11-01

    Capillary phenomena associated with fluids wetting other condensed matter phases have drawn great scientific interest for hundreds of years; consider the recent bicentennial celebration of Thomas Young's paper on equilibrium contact angles, describing the geometric shape assumed near a three phase contact line in terms of the relevant surface energies of the constituent phases [1]. Indeed, nearly a century has passed since the seminal papers of Lucas and Washburn, describing dynamics of capillary imbibition [2, 3]. While it is generally appreciated that dynamics of fluid wetting processes are determined by the degree to which a system is out of capillary equilibrium, myriad complications exist that challenge the fundamental understanding of dynamic capillary phenomena. The topic has gathered much interest from recent Nobel laureate Pierre-Gilles de Gennes, who provided a seminal review of relevant dissipation mechanisms for fluid droplets spreading on solid surfaces [4] Although much about the dynamics of wetting has been revealed, much remains to be learned and intrinsic technological and fundamental interest in the topic drives continuing high levels of research activity. This is enabled partly by improved experimental capabilities for resolving wetting processes at increasingly finer temporal, spatial, and chemical resolution. Additionally, dynamic wetting research advances via higher fidelity computational modeling capabilities, which drive more highly refined theory development. The significance of this topic both fundamentally and technologically has resulted in a number of reviews of research activity in wetting dynamics. One recent example addresses the evaluation of existing wetting dynamics theories from an experimentalist's perspective [5]. A Current Opinion issue was recently dedicated to high temperature capillarity, including dynamics of high temperature spreading [6]. New educational tools have recently emerged for providing instruction in wetting

  16. Dynamic link: user's manual

    International Nuclear Information System (INIS)

    Harada, Hiroo; Asai, Kiyoshi; Kihara, Kazuhisa.

    1981-09-01

    The purpose of dynamic link facility is to link a load module dynamically only when it is used in execution time. The facility is very useful for development, execution and maintenance of a large scale computer program which is too big to be saved as one load module in main memory, or it is poor economy to save it due to many unused subroutines depending on an input. It is also useful for standardization and common utilization of programs. Standard usage of dynamic link facility of FACOM M-200 computer system, a software tool which analyzes the effect of dynamic link facility and application of dynamic link to nuclear codes are described. (author)

  17. Complexity and Dynamical Depth

    Directory of Open Access Journals (Sweden)

    Terrence Deacon

    2014-07-01

    Full Text Available We argue that a critical difference distinguishing machines from organisms and computers from brains is not complexity in a structural sense, but a difference in dynamical organization that is not well accounted for by current complexity measures. We propose a measure of the complexity of a system that is largely orthogonal to computational, information theoretic, or thermodynamic conceptions of structural complexity. What we call a system’s dynamical depth is a separate dimension of system complexity that measures the degree to which it exhibits discrete levels of nonlinear dynamical organization in which successive levels are distinguished by local entropy reduction and constraint generation. A system with greater dynamical depth than another consists of a greater number of such nested dynamical levels. Thus, a mechanical or linear thermodynamic system has less dynamical depth than an inorganic self-organized system, which has less dynamical depth than a living system. Including an assessment of dynamical depth can provide a more precise and systematic account of the fundamental difference between inorganic systems (low dynamical depth and living systems (high dynamical depth, irrespective of the number of their parts and the causal relations between them.

  18. Dynamic and quasi-dynamic multileaf collimation

    International Nuclear Information System (INIS)

    Bortfeld, T.

    1995-01-01

    Several recent investigations deal with the problem of how to produce arbitrary two-dimensional x-ray fluence distributions by means of a multileaf collimator (MLC), an approach, which could be called multileaf modulation. The goal of this approach is to facilitate the delivery of compensated or intensity-modulated fields. The present work gives an overview of these developments. The hardware requirements on MLCs for this special application are specified. Most commercially available MLCs fulfill these requirement sufficiently, however, the MLC control software is generally not capable of controlling an MLC dynamically. There is also the question of how to verify the dynamic movement of the leaves. Some minimum requirements on a control software suitable for application in clinical practice are therefore specified. An alternative, the stepwise or 'quasi-dynamic' movement of the MLC-leaves, is also discussed with respect to practicality. In this case the control is easier, but the demands on the stability of the accelerator for small dose deliveries are higher. Nevertheless, it can be expected that, for reasons of ease of control and verification, the quasi-dynamic technique will become the method of choice in the near future, while the slightly more effective fully dynamic technique will become available later in the future. In any case, multileaf modulation is an interesting and important alternative to the tomotherapy-concept

  19. Synchronization dynamics of two different dynamical systems

    International Nuclear Information System (INIS)

    Luo, Albert C.J.; Min Fuhong

    2011-01-01

    Highlights: → Synchronization dynamics of two distinct dynamical systems. → Synchronization, de-synchronization and instantaneous synchronization. → A controlled pendulum synchronizing with the Duffing oscillator. → Synchronization invariant set. → Synchronization parameter map. - Abstract: In this paper, synchronization dynamics of two different dynamical systems is investigated through the theory of discontinuous dynamical systems. The necessary and sufficient conditions for the synchronization, de-synchronization and instantaneous synchronization (penetration or grazing) are presented. Using such a synchronization theory, the synchronization of a controlled pendulum with the Duffing oscillator is systematically discussed as a sampled problem, and the corresponding analytical conditions for the synchronization are presented. The synchronization parameter study is carried out for a better understanding of synchronization characteristics of the controlled pendulum and the Duffing oscillator. Finally, the partial and full synchronizations of the controlled pendulum with periodic and chaotic motions are presented to illustrate the analytical conditions. The synchronization of the Duffing oscillator and pendulum are investigated in order to show the usefulness and efficiency of the methodology in this paper. The synchronization invariant domain is obtained. The technique presented in this paper should have a wide spectrum of applications in engineering. For example, this technique can be applied to the maneuvering target tracking, and the others.

  20. Dynamic Boiler Performance

    DEFF Research Database (Denmark)

    Sørensen, Kim

    Traditionally, boilers have been designed mainly focussing on the static operation of the plant. The dynamic capability has been given lower priority and the analysis has typically been limited to assuring that the plant was not over-stressed due to large temperature gradients. New possibilities...... developed. Analyzing boilers for dynamic operation gives rise to a number of opposing aims: shrinking and swelling, steam quality, stress levels, control system/philosophy, pressurization etc. Common for these opposing aims is that an optimum can be found for selected operation conditions. The framework has...... for buying and selling energy has increased the focus on the dynamic operation capability, efciency, emissions etc. For optimizing the design of boilers for dynamic operation a quantication of the dynamic capability is needed. A framework for optimizing design of boilers for dynamic operation has been...

  1. Nonlinear dynamics and astrophysics

    International Nuclear Information System (INIS)

    Vallejo, J. C.; Sanjuan, M. A. F.

    2000-01-01

    Concepts and techniques from Nonlinear Dynamics, also known as Chaos Theory, have been applied successfully to several astrophysical fields such as orbital motion, time series analysis or galactic dynamics, providing answers to old questions but also opening a few new ones. Some of these topics are described in this review article, showing the basis of Nonlinear Dynamics, and how it is applied in Astrophysics. (Author)

  2. Record Statistics and Dynamics

    DEFF Research Database (Denmark)

    Sibani, Paolo; Jensen, Henrik J.

    2009-01-01

    with independent random increments. The term record dynamics covers the rather new idea that records may, in special situations, have measurable dynamical consequences. The approach applies to the aging dynamics of glasses and other systems with multiple metastable states. The basic idea is that record sizes...... fluctuations of e. g. the energy are able to push the system past some sort of ‘edge of stability’, inducing irreversible configurational changes, whose statistics then closely follows the statistics of record fluctuations....

  3. Dynamics of unstable systems

    International Nuclear Information System (INIS)

    Posch, H.A.; Narnhofer, H.; Thirring, W.

    1990-01-01

    We study the dynamics of classical particles interacting with attractive Gaussian potentials. This system is thermodynamically not stable and exhibits negative specific heat. The results of the computer simulation of the dynamics are discussed in comparison with various theories. In particular, we find that the condensed phase is a stationary solution of the Vlasov equation, but the Vlasov dynamics cannot describe the collapse. 14 refs., 1 tab., 11 figs. (Authors)

  4. Dynamical principles in neuroscience

    International Nuclear Information System (INIS)

    Rabinovich, Mikhail I.; Varona, Pablo; Selverston, Allen I.; Abarbanel, Henry D. I.

    2006-01-01

    Dynamical modeling of neural systems and brain functions has a history of success over the last half century. This includes, for example, the explanation and prediction of some features of neural rhythmic behaviors. Many interesting dynamical models of learning and memory based on physiological experiments have been suggested over the last two decades. Dynamical models even of consciousness now exist. Usually these models and results are based on traditional approaches and paradigms of nonlinear dynamics including dynamical chaos. Neural systems are, however, an unusual subject for nonlinear dynamics for several reasons: (i) Even the simplest neural network, with only a few neurons and synaptic connections, has an enormous number of variables and control parameters. These make neural systems adaptive and flexible, and are critical to their biological function. (ii) In contrast to traditional physical systems described by well-known basic principles, first principles governing the dynamics of neural systems are unknown. (iii) Many different neural systems exhibit similar dynamics despite having different architectures and different levels of complexity. (iv) The network architecture and connection strengths are usually not known in detail and therefore the dynamical analysis must, in some sense, be probabilistic. (v) Since nervous systems are able to organize behavior based on sensory inputs, the dynamical modeling of these systems has to explain the transformation of temporal information into combinatorial or combinatorial-temporal codes, and vice versa, for memory and recognition. In this review these problems are discussed in the context of addressing the stimulating questions: What can neuroscience learn from nonlinear dynamics, and what can nonlinear dynamics learn from neuroscience?

  5. Dynamical principles in neuroscience

    Science.gov (United States)

    Rabinovich, Mikhail I.; Varona, Pablo; Selverston, Allen I.; Abarbanel, Henry D. I.

    2006-10-01

    Dynamical modeling of neural systems and brain functions has a history of success over the last half century. This includes, for example, the explanation and prediction of some features of neural rhythmic behaviors. Many interesting dynamical models of learning and memory based on physiological experiments have been suggested over the last two decades. Dynamical models even of consciousness now exist. Usually these models and results are based on traditional approaches and paradigms of nonlinear dynamics including dynamical chaos. Neural systems are, however, an unusual subject for nonlinear dynamics for several reasons: (i) Even the simplest neural network, with only a few neurons and synaptic connections, has an enormous number of variables and control parameters. These make neural systems adaptive and flexible, and are critical to their biological function. (ii) In contrast to traditional physical systems described by well-known basic principles, first principles governing the dynamics of neural systems are unknown. (iii) Many different neural systems exhibit similar dynamics despite having different architectures and different levels of complexity. (iv) The network architecture and connection strengths are usually not known in detail and therefore the dynamical analysis must, in some sense, be probabilistic. (v) Since nervous systems are able to organize behavior based on sensory inputs, the dynamical modeling of these systems has to explain the transformation of temporal information into combinatorial or combinatorial-temporal codes, and vice versa, for memory and recognition. In this review these problems are discussed in the context of addressing the stimulating questions: What can neuroscience learn from nonlinear dynamics, and what can nonlinear dynamics learn from neuroscience?

  6. Computational Fluid Dynamics

    International Nuclear Information System (INIS)

    Myeong, Hyeon Guk

    1999-06-01

    This book deals with computational fluid dynamics with basic and history of numerical fluid dynamics, introduction of finite volume method using one-dimensional heat conduction equation, solution of two-dimensional heat conduction equation, solution of Navier-Stokes equation, fluid with heat transport, turbulent flow and turbulent model, Navier-Stokes solution by generalized coordinate system such as coordinate conversion, conversion of basic equation, program and example of calculation, application of abnormal problem and high speed solution of numerical fluid dynamics.

  7. Double dynamic scaling in human communication dynamics

    Science.gov (United States)

    Wang, Shengfeng; Feng, Xin; Wu, Ye; Xiao, Jinhua

    2017-05-01

    In the last decades, human behavior has been deeply understanding owing to the huge quantities data of human behavior available for study. The main finding in human dynamics shows that temporal processes consist of high-activity bursty intervals alternating with long low-activity periods. A model, assuming the initiator of bursty follow a Poisson process, is widely used in the modeling of human behavior. Here, we provide further evidence for the hypothesis that different bursty intervals are independent. Furthermore, we introduce a special threshold to quantitatively distinguish the time scales of complex dynamics based on the hypothesis. Our results suggest that human communication behavior is a composite process of double dynamics with midrange memory length. The method for calculating memory length would enhance the performance of many sequence-dependent systems, such as server operation and topic identification.

  8. Introduction to dynamic programming

    CERN Document Server

    Cooper, Leon; Rodin, E Y

    1981-01-01

    Introduction to Dynamic Programming provides information pertinent to the fundamental aspects of dynamic programming. This book considers problems that can be quantitatively formulated and deals with mathematical models of situations or phenomena that exists in the real world.Organized into 10 chapters, this book begins with an overview of the fundamental components of any mathematical optimization model. This text then presents the details of the application of dynamic programming to variational problems. Other chapters consider the application of dynamic programming to inventory theory, Mark

  9. Essential dynamics and relativity

    CERN Document Server

    O'Donnell, Peter J

    2014-01-01

    Essential Dynamics & Relativity provides students with an introduction to the core aspects of dynamics and special relativity. The author reiterates important ideas and terms throughout and covers concepts that are often missing from other textbooks at this level. He also places each topic within the wider constructs of the theory, without jumping from topic to topic to illustrate a point.The first section of the book focuses on dynamics, discussing the basic aspects of single particle motion and analyzing the motion of multi-particle systems. The book also explains the dynamical behavior of b

  10. Dynamical Systems Conference

    CERN Document Server

    Gils, S; Hoveijn, I; Takens, F; Nonlinear Dynamical Systems and Chaos

    1996-01-01

    Symmetries in dynamical systems, "KAM theory and other perturbation theories", "Infinite dimensional systems", "Time series analysis" and "Numerical continuation and bifurcation analysis" were the main topics of the December 1995 Dynamical Systems Conference held in Groningen in honour of Johann Bernoulli. They now form the core of this work which seeks to present the state of the art in various branches of the theory of dynamical systems. A number of articles have a survey character whereas others deal with recent results in current research. It contains interesting material for all members of the dynamical systems community, ranging from geometric and analytic aspects from a mathematical point of view to applications in various sciences.

  11. Engineering quantum dynamics

    International Nuclear Information System (INIS)

    Lloyd, Seth; Viola, Lorenza

    2002-01-01

    The ability to perform measurements on a quantum system, combined with the ability to feed back the measurement results via coherent control, allows one to control the system to follow any desired coherent or incoherent quantum dynamics. Such universal dynamical control can be achieved, in principle, through the repeated application of only two coherent control operations and a simple 'Yes-No' measurement. As a consequence, a quantum computer can simulate an arbitrary open-system dynamics using just one qubit more than required to simulate closed-system dynamics

  12. Modern fluid dynamics

    CERN Document Server

    Kleinstreuer, Clement

    2018-01-01

    Modern Fluid Dynamics, Second Edition provides up-to-date coverage of intermediate and advanced fluids topics. The text emphasizes fundamentals and applications, supported by worked examples and case studies. Scale analysis, non-Newtonian fluid flow, surface coating, convection heat transfer, lubrication, fluid-particle dynamics, microfluidics, entropy generation, and fluid-structure interactions are among the topics covered. Part A presents fluids principles, and prepares readers for the applications of fluid dynamics covered in Part B, which includes computer simulations and project writing. A review of the engineering math needed for fluid dynamics is included in an appendix.

  13. Control of dynamical localization

    International Nuclear Information System (INIS)

    Gong Jiangbin; Woerner, Hans Jakob; Brumer, Paul

    2003-01-01

    Control over the quantum dynamics of chaotic kicked rotor systems is demonstrated. Specifically, control over a number of quantum coherent phenomena is achieved by a simple modification of the kicking field. These include the enhancement of the dynamical localization length, the introduction of classical anomalous diffusion assisted control for systems far from the semiclassical regime, and the observation of a variety of strongly nonexponential line shapes for dynamical localization. The results provide excellent examples of controlled quantum dynamics in a system that is classically chaotic and offer opportunities to explore quantum fluctuations and correlations in quantum chaos

  14. Nonlinear dynamics and complexity

    CERN Document Server

    Luo, Albert; Fu, Xilin

    2014-01-01

    This important collection presents recent advances in nonlinear dynamics including analytical solutions, chaos in Hamiltonian systems, time-delay, uncertainty, and bio-network dynamics. Nonlinear Dynamics and Complexity equips readers to appreciate this increasingly main-stream approach to understanding complex phenomena in nonlinear systems as they are examined in a broad array of disciplines. The book facilitates a better understanding of the mechanisms and phenomena in nonlinear dynamics and develops the corresponding mathematical theory to apply nonlinear design to practical engineering.

  15. Structural Dynamics Laboratory (SDL)

    Data.gov (United States)

    Federal Laboratory Consortium — Structural dynamic testing is performed to verify the survivability of a component or assembly when exposed to vibration stress screening, or a controlled simulation...

  16. Vegetation dynamics and dynamic vegetation science

    NARCIS (Netherlands)

    Van der Maarel, E

    1996-01-01

    his contribution presents a review of the development of the study of vegetation dynamics since 1979, in the framework of a jubilee meeting on progress in the study of vegetation. However, an exhaustive review is both impossible and unnecessary. It is impossible within the few pages available

  17. Dynamic defense workshop :

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, Sean Michael; Doak, Justin E.; Haas, Jason Juedes.; Helinski, Ryan; Lamb, Christopher C.

    2013-02-01

    On September 5th and 6th, 2012, the Dynamic Defense Workshop: From Research to Practice brought together researchers from academia, industry, and Sandia with the goals of increasing collaboration between Sandia National Laboratories and external organizations, de ning and un- derstanding dynamic, or moving target, defense concepts and directions, and gaining a greater understanding of the state of the art for dynamic defense. Through the workshop, we broadened and re ned our de nition and understanding, identi ed new approaches to inherent challenges, and de ned principles of dynamic defense. Half of the workshop was devoted to presentations of current state-of-the-art work. Presentation topics included areas such as the failure of current defenses, threats, techniques, goals of dynamic defense, theory, foundations of dynamic defense, future directions and open research questions related to dynamic defense. The remainder of the workshop was discussion, which was broken down into sessions on de ning challenges, applications to host or mobile environments, applications to enterprise network environments, exploring research and operational taxonomies, and determining how to apply scienti c rigor to and investigating the eld of dynamic defense.

  18. Structural Dynamics, Vol. 9

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.

    This book has been prepared for the course on Computational Dynamics given at the 8th semester at the structural program in civil engineering at Aalborg University.......This book has been prepared for the course on Computational Dynamics given at the 8th semester at the structural program in civil engineering at Aalborg University....

  19. Nonlinear dynamics in Nuclotron

    International Nuclear Information System (INIS)

    Dinev, D.

    1997-01-01

    The paper represents an extensive study of the nonlinear beam dynamics in the Nuclotron. Chromatic effects, including the dependence of the betatron tunes on the amplitude, and chromatic perturbations have been investigated taking into account the measured field imperfections. Beam distortion, smear, dynamic aperture and nonlinear acceptance have been calculated for different particle energies and betatron tunes

  20. Dynamic Shannon Coding

    OpenAIRE

    Gagie, Travis

    2005-01-01

    We present a new algorithm for dynamic prefix-free coding, based on Shannon coding. We give a simple analysis and prove a better upper bound on the length of the encoding produced than the corresponding bound for dynamic Huffman coding. We show how our algorithm can be modified for efficient length-restricted coding, alphabetic coding and coding with unequal letter costs.

  1. Dynamic paradigm of turbulence

    International Nuclear Information System (INIS)

    Mukhamedov, Alfred M.

    2006-01-01

    In this paper a dynamic paradigm of turbulence is proposed. The basic idea consists in the novel definition of chaotic structure given with the help of Pfaff system of PDE associated with the turbulent dynamics. A methodological analysis of the new and the former paradigm is produced

  2. Dynamic Capabilities and Performance

    DEFF Research Database (Denmark)

    Wilden, Ralf; Gudergan, Siegfried P.; Nielsen, Bo Bernhard

    2013-01-01

    are contingent on the competitive intensity faced by firms. Our findings demonstrate the performance effects of internal alignment between organizational structure and dynamic capabilities, as well as the external fit of dynamic capabilities with competitive intensity. We outline the advantages of PLS...

  3. Dynamic Gaming Platform (DGP)

    Science.gov (United States)

    2009-04-01

    GAMING PLATFORM (DGP) Lockheed Martin Corporation...YYYY) APR 09 2. REPORT TYPE Final 3. DATES COVERED (From - To) Jul 07 – Mar 09 4. TITLE AND SUBTITLE DYNAMIC GAMING PLATFORM (DGP) 5a...CMU Carnegie Mellon University DGP Dynamic Gaming Platform GA Genetic Algorithm IARPA Intelligence Advanced Research Projects Activity LM ATL Lockheed Martin Advanced Technology Laboratories PAINT ProActive INTelligence

  4. Dynamic covalent surfactants

    NARCIS (Netherlands)

    Minkenberg, C.B.

    2012-01-01

    In this thesis the development of surfactant aggregates with fast exchange dynamics between the aggregated and non-aggregated state is described. Dynamic surfactant exchange plays an important role in natural systems, for instance in cell signaling, cell division, and uptake and release of cargo.

  5. Dynamics on the Circle

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 11. Dynamics on the Circle - Interval Dynamics and Rotation Number. Siddhartha Gadgil. General Article Volume 8 Issue 11 November 2003 pp 25-36. Fulltext. Click here to view fulltext PDF. Permanent link:

  6. Dynamic Speaking Assessments

    Science.gov (United States)

    Hill, Kent; Sabet, Mehran

    2009-01-01

    This article describes an attempt to adopt dynamic assessment (DA) methods in classroom speaking assessments. The study reported in this article focused on four particular applications of dynamic speaking assessment (DSA). The first, "mediated assistance" (MA), involves interaction between an assistor and a learner to reveal problems in…

  7. Dynamical supersymmetry breaking

    International Nuclear Information System (INIS)

    Affleck, I.

    1985-03-01

    Supersymmetry, and in particular, dynamical supersymmetry breaking, offers the hope of a natural solution of the gauge hierarchy problem in grand unification. I briefly review recent work on dynamical supersymmetry breaking in four-dimensional Higgs theories and its application to grand unified model building

  8. Dynamic Latent Classification Model

    DEFF Research Database (Denmark)

    Zhong, Shengtong; Martínez, Ana M.; Nielsen, Thomas Dyhre

    as possible. Motivated by this problem setting, we propose a generative model for dynamic classification in continuous domains. At each time point the model can be seen as combining a naive Bayes model with a mixture of factor analyzers (FA). The latent variables of the FA are used to capture the dynamics...

  9. Dynamic combinatorial chemistry

    NARCIS (Netherlands)

    Otto, Sijbren; Furlan, Ricardo L.E.; Sanders, Jeremy K.M.

    2002-01-01

    A combinatorial library that responds to its target by increasing the concentration of strong binders at the expense of weak binders sounds ideal. Dynamic combinatorial chemistry has the potential to achieve exactly this. In this review, we will highlight the unique features that distinguish dynamic

  10. Bursty human dynamics

    CERN Document Server

    Karsai, Márton; Kaski, Kimmo

    2018-01-01

    This book provides a comprehensive overview on emergent bursty patterns in the dynamics of human behaviour. It presents common and alternative understanding of the investigated phenomena, and points out open questions worthy of further investigations. The book is structured as follows. In the introduction the authors discuss the motivation of the field, describe bursty phenomena in case of human behaviour, and relate it to other disciplines. The second chapter addresses the measures commonly used to characterise heterogeneous signals, bursty human dynamics, temporal paths, and correlated behaviour. These definitions are first introduced to set the basis for the discussion of the third chapter about the observations of bursty human patterns in the dynamics of individuals, dyadic interactions, and collective behaviour. The subsequent fourth chapter discusses the models of bursty human dynamics. Various mechanisms have been proposed about the source of the heterogeneities in human dynamics, which leads to the in...

  11. Nonlinear dynamics of structures

    CERN Document Server

    Oller, Sergio

    2014-01-01

    This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics.   This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects.   Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution  are studied, and the theoretical concepts and its programming algorithms are presented.  

  12. Vehicle Dynamics and Control

    CERN Document Server

    Rajamani, Rajesh

    2012-01-01

    Vehicle Dynamics and Control provides a comprehensive coverage of vehicle control systems and the dynamic models used in the development of these control systems. The control system applications covered in the book include cruise control, adaptive cruise control, ABS, automated lane keeping, automated highway systems, yaw stability control, engine control, passive, active and semi-active suspensions, tire-road friction coefficient estimation, rollover prevention, and hybrid electric vehicle. In developing the dynamic model for each application, an effort is made to both keep the model simple enough for control system design but at the same time rich enough to capture the essential features of the dynamics. A special effort has been made to explain the several different tire models commonly used in literature and to interpret them physically. In the second edition of the book, chapters on roll dynamics, rollover prevention and hybrid electric vehicles have been added, and the chapter on electronic stability co...

  13. Bayesian dynamic mediation analysis.

    Science.gov (United States)

    Huang, Jing; Yuan, Ying

    2017-12-01

    Most existing methods for mediation analysis assume that mediation is a stationary, time-invariant process, which overlooks the inherently dynamic nature of many human psychological processes and behavioral activities. In this article, we consider mediation as a dynamic process that continuously changes over time. We propose Bayesian multilevel time-varying coefficient models to describe and estimate such dynamic mediation effects. By taking the nonparametric penalized spline approach, the proposed method is flexible and able to accommodate any shape of the relationship between time and mediation effects. Simulation studies show that the proposed method works well and faithfully reflects the true nature of the mediation process. By modeling mediation effect nonparametrically as a continuous function of time, our method provides a valuable tool to help researchers obtain a more complete understanding of the dynamic nature of the mediation process underlying psychological and behavioral phenomena. We also briefly discuss an alternative approach of using dynamic autoregressive mediation model to estimate the dynamic mediation effect. The computer code is provided to implement the proposed Bayesian dynamic mediation analysis. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  14. Dynamics of aesthetic appreciation

    Science.gov (United States)

    Carbon, Claus-Christian

    2012-03-01

    Aesthetic appreciation is a complex cognitive processing with inherent aspects of cold as well as hot cognition. Research from the last decades of empirical has shown that evaluations of aesthetic appreciation are highly reliable. Most frequently, facial attractiveness was used as the corner case for investigating aesthetic appreciation. Evaluating facial attractiveness shows indeed high internal consistencies and impressively high inter-rater reliabilities, even across cultures. Although this indicates general and stable mechanisms underlying aesthetic appreciation, it is also obvious that our taste for specific objects changes dynamically. Aesthetic appreciation on artificial object categories, such as fashion, design or art is inherently very dynamic. Gaining insights into the cognitive mechanisms that trigger and enable corresponding changes of aesthetic appreciation is of particular interest for research as this will provide possibilities to modeling aesthetic appreciation for longer durations and from a dynamic perspective. The present paper refers to a recent two-step model ("the dynamical two-step-model of aesthetic appreciation"), dynamically adapting itself, which accounts for typical dynamics of aesthetic appreciation found in different research areas such as art history, philosophy and psychology. The first step assumes singular creative sources creating and establishing innovative material towards which, in a second step, people adapt by integrating it into their visual habits. This inherently leads to dynamic changes of the beholders' aesthetic appreciation.

  15. Perspectives of nonlinear dynamics

    International Nuclear Information System (INIS)

    Jackson, E.A.

    1985-03-01

    Four lectures were given weekly in October and November, 1984, and some of the ideas presented here will be of use in the future. First, a brief survey of the historical development of nonlinear dynamics since about 1890 was given, and then, a few topics were discussed in detail. The objective was to introduce some of many concepts and methods which are presently used for describing nonlinear dynamics. The symbiotic relationship between sciences of all types and mathematics, two main categories of the models describing nature, the method for describing the dynamics of a system, the idea of control parameters and topological dimension, the asymptotic properties of dynamics, abstract dynamics, the concept of embedding, singular perturbation theory, strange attractor, Fermi-Pasta-Ulam phenomena, an example of computer heuristics, the idea of elementary catastrophe theory and so on were explained. The logistic map is the simplest introduction to complex dynamics. The complicated dynamics is referred to as strange attractors. Two-dimensional maps are the highest dimensional maps commonly studied. These were discussed in detail. (Kako, I.)

  16. Operational Dynamic Configuration Analysis

    Science.gov (United States)

    Lai, Chok Fung; Zelinski, Shannon

    2010-01-01

    Sectors may combine or split within areas of specialization in response to changing traffic patterns. This method of managing capacity and controller workload could be made more flexible by dynamically modifying sector boundaries. Much work has been done on methods for dynamically creating new sector boundaries [1-5]. Many assessments of dynamic configuration methods assume the current day baseline configuration remains fixed [6-7]. A challenging question is how to select a dynamic configuration baseline to assess potential benefits of proposed dynamic configuration concepts. Bloem used operational sector reconfigurations as a baseline [8]. The main difficulty is that operational reconfiguration data is noisy. Reconfigurations often occur frequently to accommodate staff training or breaks, or to complete a more complicated reconfiguration through a rapid sequence of simpler reconfigurations. Gupta quantified a few aspects of airspace boundary changes from this data [9]. Most of these metrics are unique to sector combining operations and not applicable to more flexible dynamic configuration concepts. To better understand what sort of reconfigurations are acceptable or beneficial, more configuration change metrics should be developed and their distribution in current practice should be computed. This paper proposes a method to select a simple sequence of configurations among operational configurations to serve as a dynamic configuration baseline for future dynamic configuration concept assessments. New configuration change metrics are applied to the operational data to establish current day thresholds for these metrics. These thresholds are then corroborated, refined, or dismissed based on airspace practitioner feedback. The dynamic configuration baseline selection method uses a k-means clustering algorithm to select the sequence of configurations and trigger times from a given day of operational sector combination data. The clustering algorithm selects a simplified

  17. Dynamic training algorithm for dynamic neural networks

    International Nuclear Information System (INIS)

    Tan, Y.; Van Cauwenberghe, A.; Liu, Z.

    1996-01-01

    The widely used backpropagation algorithm for training neural networks based on the gradient descent has a significant drawback of slow convergence. A Gauss-Newton method based recursive least squares (RLS) type algorithm with dynamic error backpropagation is presented to speed-up the learning procedure of neural networks with local recurrent terms. Finally, simulation examples concerning the applications of the RLS type algorithm to identification of nonlinear processes using a local recurrent neural network are also included in this paper

  18. Living with Dynamic Concepts in Dynamic Environments

    DEFF Research Database (Denmark)

    Rehm, Matthias

    2003-01-01

    a dynamic perspective, concepts depend on different factors like the learning process, the environment, i.e. the situational setting. It is indispensable for an agent to create individual concepts that adhere to restrictions imposed by the environment and the society it is living in. It is shown...... that changes in the environment lead to changes in existing concepts and to establishing new ones with only a small irritation in the use of the old ones....

  19. Fluid dynamics transactions

    CERN Document Server

    Fiszdon, W

    1965-01-01

    Fluid Dynamics Transactions, Volume 2 compiles 46 papers on fluid dynamics, a subdiscipline of fluid mechanics that deals with fluid flow. The topics discussed in this book include developments in interference theory for aeronautical applications; diffusion from sources in a turbulent boundary layer; unsteady motion of a finite wing span in a compressible medium; and wall pressure covariance and comparison with experiment. The certain classes of non-stationary axially symmetric flows in magneto-gas-dynamics; description of the phenomenon of secondary flows in curved channels by means of co

  20. Advances in Dynamic Games

    CERN Document Server

    Breton, Michele

    2011-01-01

    This book focuses on various aspects of dynamic game theory, presenting state-of-the-art research and serving as a testament to the vitality and growth of the field of dynamic games and their applications. The selected contributions, written by experts in their respective disciplines, are outgrowths of presentations originally given at the 13th International Symposium of Dynamic Games and Applications held in WrocACaw. The book covers a variety of topics, ranging from theoretical developments in game theory and algorithmic methods to applications, examples, and analysis in fields as varied as

  1. Basic structural dynamics

    CERN Document Server

    Anderson, James C

    2012-01-01

    A concise introduction to structural dynamics and earthquake engineering Basic Structural Dynamics serves as a fundamental introduction to the topic of structural dynamics. Covering single and multiple-degree-of-freedom systems while providing an introduction to earthquake engineering, the book keeps the coverage succinct and on topic at a level that is appropriate for undergraduate and graduate students. Through dozens of worked examples based on actual structures, it also introduces readers to MATLAB, a powerful software for solving both simple and complex structural d

  2. High enthalpy gas dynamics

    CERN Document Server

    Rathakrishnan, Ethirajan

    2014-01-01

    This is an introductory level textbook which explains the elements of high temperature and high-speed gas dynamics. written in a clear and easy to follow style, the author covers all the latest developments in the field including basic thermodynamic principles, compressible flow regimes and waves propagation in one volume covers theoretical modeling of High Enthalpy Flows, with particular focus on problems in internal and external gas-dynamic flows, of interest in the fields of rockets propulsion and hypersonic aerodynamics High enthalpy gas dynamics is a compulsory course for aerospace engine

  3. Shadowing in dynamical systems

    CERN Document Server

    Pilyugin, Sergei Yu

    1999-01-01

    This book is an introduction to the theory of shadowing of approximate trajectories in dynamical systems by exact ones. This is the first book completely devoted to the theory of shadowing. It shows the importance of shadowing theory for both the qualitative theory of dynamical systems and the theory of numerical methods. Shadowing Methods allow us to estimate differences between exact and approximate solutions on infinite time intervals and to understand the influence of error terms. The book is intended for specialists in dynamical systems, for researchers and graduate students in the theory of numerical methods.

  4. Dynamics from diffraction

    International Nuclear Information System (INIS)

    Goodwin, Andrew L.; Tucker, Matthew G.; Cope, Elizabeth R.; Dove, Martin T.; Keen, David A.

    2006-01-01

    We explore the possibility that detailed dynamical information might be extracted from powder diffraction data. Our focus is a recently reported technique that employs statistical analysis of atomistic configurations to calculate dynamical properties from neutron total scattering data. We show that it is possible to access the phonon dispersion of low-frequency modes using such an approach, without constraining the results in terms of some pre-defined dynamical model. The high-frequency regions of the phonon spectrum are found to be less well preserved in the diffraction data

  5. Fundamentals of gas dynamics

    CERN Document Server

    Babu, V

    2014-01-01

    Fundamentals of Gas Dynamics, Second Edition isa comprehensively updated new edition and now includes a chapter on the gas dynamics of steam. It covers the fundamental concepts and governing equations of different flows, and includes end of chapter exercises based on the practical applications. A number of useful tables on the thermodynamic properties of steam are also included.Fundamentals of Gas Dynamics, Second Edition begins with an introduction to compressible and incompressible flows before covering the fundamentals of one dimensional flows and normal shock wav

  6. Stability of dynamical systems

    CERN Document Server

    Liao, Xiaoxin; Yu, P 0

    2007-01-01

    The main purpose of developing stability theory is to examine dynamic responses of a system to disturbances as the time approaches infinity. It has been and still is the object of intense investigations due to its intrinsic interest and its relevance to all practical systems in engineering, finance, natural science and social science. This monograph provides some state-of-the-art expositions of major advances in fundamental stability theories and methods for dynamic systems of ODE and DDE types and in limit cycle, normal form and Hopf bifurcation control of nonlinear dynamic systems.ʺ Presents

  7. Dynamics at the nanoscale

    International Nuclear Information System (INIS)

    Stoneham, A.M.; Gavartin, J.L.

    2007-01-01

    However fascinating structures may be at the nanoscale, time-dependent behaviour at the nanoscale has far greater importance. Some of the dynamics is random, with fluctuations controlling rate processes and making thermal ratchets possible. Some of the dynamics causes the transfer of energy, of signals, or of charge. Such transfers are especially efficiently controlled in biological systems. Other dynamical processes occur when we wish to control the nanoscale, e.g., to avoid local failures of gate dielectrics, or to manipulate structures by electronic excitation, to use spin manipulation in quantum information processing. Our prime purpose is to make clear the enormous range and variety of time-dependent nanoscale phenomena

  8. Theoretical Fluid Dynamics

    CERN Document Server

    Shivamoggi, Bhimsen K

    1998-01-01

    "Although there are many texts and monographs on fluid dynamics, I do not know of any which is as comprehensive as the present book. It surveys nearly the entire field of classical fluid dynamics in an advanced, compact, and clear manner, and discusses the various conceptual and analytical models of fluid flow." - Foundations of Physics on the first edition. Theoretical Fluid Dynamics functions equally well as a graduate-level text and a professional reference. Steering a middle course between the empiricism of engineering and the abstractions of pure mathematics, the author focuses

  9. Discrete Dynamics Lab

    Science.gov (United States)

    Wuensche, Andrew

    DDLab is interactive graphics software for creating, visualizing, and analyzing many aspects of Cellular Automata, Random Boolean Networks, and Discrete Dynamical Networks in general and studying their behavior, both from the time-series perspective — space-time patterns, and from the state-space perspective — attractor basins. DDLab is relevant to research, applications, and education in the fields of complexity, self-organization, emergent phenomena, chaos, collision-based computing, neural networks, content addressable memory, genetic regulatory networks, dynamical encryption, generative art and music, and the study of the abstract mathematical/physical/dynamical phenomena in their own right.

  10. Dynamic Systems and Control Engineering

    International Nuclear Information System (INIS)

    Kim, Jong Seok

    1994-02-01

    This book deals with introduction of dynamic system and control engineering, frequency domain modeling of dynamic system, temporal modeling of dynamic system, typical dynamic system and automatic control device, performance and stability of control system, root locus analysis, analysis of frequency domain dynamic system, design of frequency domain dynamic system, design and analysis of space, space of control system and digital control system such as control system design of direct digital and digitalization of consecutive control system.

  11. Dynamic Systems and Control Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seok

    1994-02-15

    This book deals with introduction of dynamic system and control engineering, frequency domain modeling of dynamic system, temporal modeling of dynamic system, typical dynamic system and automatic control device, performance and stability of control system, root locus analysis, analysis of frequency domain dynamic system, design of frequency domain dynamic system, design and analysis of space, space of control system and digital control system such as control system design of direct digital and digitalization of consecutive control system.

  12. Liquid Sloshing Dynamics

    Science.gov (United States)

    Ibrahim, Raouf A.

    2005-06-01

    The problem of liquid sloshing in moving or stationary containers remains of great concern to aerospace, civil, and nuclear engineers; physicists; designers of road tankers and ship tankers; and mathematicians. Beginning with the fundamentals of liquid sloshing theory, this book takes the reader systematically from basic theory to advanced analytical and experimental results in a self-contained and coherent format. The book is divided into four sections. Part I deals with the theory of linear liquid sloshing dynamics; Part II addresses the nonlinear theory of liquid sloshing dynamics, Faraday waves, and sloshing impacts; Part III presents the problem of linear and nonlinear interaction of liquid sloshing dynamics with elastic containers and supported structures; and Part IV considers the fluid dynamics in spinning containers and microgravity sloshing. This book will be invaluable to researchers and graduate students in mechanical and aeronautical engineering, designers of liquid containers, and applied mathematicians.

  13. Ansatz for dynamical hierarchies

    DEFF Research Database (Denmark)

    Rasmussen, S.; Baas, N.A.; Mayer, B.

    2001-01-01

    Complex, robust functionalities can be generated naturally in at least two ways: by the assembly of structures and by the evolution of structures. This work is concerned with spontaneous formation of structures. We define the notion of dynamical hierarchies in natural systems and show...... the importance of this particular kind of organization for living systems. We then define a framework that enables us to formulate, investigate, and manipulate such dynamical hierarchies. This framework allows us to simultaneously investigate different levels of description together with them interrelationship...... three. Formulating this system as a simple two-dimensional molecular dynamics (MD) lattice gas allows us within one dynamical system to demonstrate the successive emergence of two higher levels (three levels all together) of robust structures with associated properties. Second, we demonstrate how...

  14. Longitudinal beam dynamics

    International Nuclear Information System (INIS)

    Tecker, F

    2014-01-01

    The course gives a summary of longitudinal beam dynamics for both linear and circular accelerators. After discussing different types of acceleration methods and synchronism conditions, it focuses on the particle motion in synchrotrons

  15. Stochastic dynamics and irreversibility

    CERN Document Server

    Tomé, Tânia

    2015-01-01

    This textbook presents an exposition of stochastic dynamics and irreversibility. It comprises the principles of probability theory and the stochastic dynamics in continuous spaces, described by Langevin and Fokker-Planck equations, and in discrete spaces, described by Markov chains and master equations. Special concern is given to the study of irreversibility, both in systems that evolve to equilibrium and in nonequilibrium stationary states. Attention is also given to the study of models displaying phase transitions and critical phenomema both in thermodynamic equilibrium and out of equilibrium. These models include the linear Glauber model, the Glauber-Ising model, lattice models with absorbing states such as the contact process and those used in population dynamic and spreading of epidemic, probabilistic cellular automata, reaction-diffusion processes, random sequential adsorption and dynamic percolation. A stochastic approach to chemical reaction is also presented.The textbook is intended for students of ...

  16. Supervision and group dynamics

    DEFF Research Database (Denmark)

    Hansen, Søren; Jensen, Lars Peter

    2004-01-01

     An important aspect of the problem based and project organized study at Aalborg University is the supervision of the project groups. At the basic education (first year) it is stated in the curriculum that part of the supervisors' job is to deal with group dynamics. This is due to the experience...... that many students are having difficulties with practical issues such as collaboration, communication, and project management. Most supervisors either ignore this demand, because they do not find it important or they find it frustrating, because they do not know, how to supervise group dynamics...... as well as at Aalborg University. The first visible result has been participating supervisors telling us that the course has inspired them to try supervising group dynamics in the future. This paper will explore some aspects of supervising group dynamics as well as, how to develop the Aalborg model...

  17. Equivalent Dynamic Models.

    Science.gov (United States)

    Molenaar, Peter C M

    2017-01-01

    Equivalences of two classes of dynamic models for weakly stationary multivariate time series are discussed: dynamic factor models and autoregressive models. It is shown that exploratory dynamic factor models can be rotated, yielding an infinite set of equivalent solutions for any observed series. It also is shown that dynamic factor models with lagged factor loadings are not equivalent to the currently popular state-space models, and that restriction of attention to the latter type of models may yield invalid results. The known equivalent vector autoregressive model types, standard and structural, are given a new interpretation in which they are conceived of as the extremes of an innovating type of hybrid vector autoregressive models. It is shown that consideration of hybrid models solves many problems, in particular with Granger causality testing.

  18. Invitation to dynamical systems

    CERN Document Server

    Scheinerman, Edward R

    2012-01-01

    This text is designed for those who wish to study mathematics beyond linear algebra but are unready for abstract material. Rather than a theorem-proof-corollary exposition, it stresses geometry, intuition, and dynamical systems. 1996 edition.

  19. Transonic Dynamics Tunnel (TDT)

    Data.gov (United States)

    Federal Laboratory Consortium — The Transonic Dynamics Tunnel (TDT) is a continuous flow wind-tunnel facility capable of speeds up to Mach 1.2 at stagnation pressures up to one atmosphere. The TDT...

  20. Advances in soil dynamics

    DEFF Research Database (Denmark)

    Advances in Soil Dynamics, Volume 3, represents the culmination of the work undertaken by the Advances in Soil Dynamics Monograph Committee, PM-45-01, about 15 years ago to summarize important developments in this field over the last 35 years. When this project was initiated, the main goal...... was to abridge major strides made in the general area of soil dynamics during the sixties, seventies, and eighties. However, by about the mid-nineties soil dynamics research in the US and much of the developed world had come to a virtual standstill. Although significant progress was made prior to the mid......-nineties, we still do not have a sound fundamental knowledge of soil-machine and soil-plant interactions. It is the hope of the editors that these three volumes will provide a ready reference for much needed future research in this area....

  1. based dynamic voltage restorer

    African Journals Online (AJOL)

    HOD

    operation due to presence of increased use of nonlinear loads (computers, microcontrollers ... simulations of a dynamic voltage restorer (DVR) was achieved using MATLAB/Simulink. ..... using Discrete PWM generator, then the IGBT inverter.

  2. Peri-dynamics

    International Nuclear Information System (INIS)

    Littlewood, D.

    2015-01-01

    Peri-dynamics, a nonlocal extension of continuum mechanics, is a natural framework for capturing constitutive response and modelling pervasive material failure and fracture. Unlike classical approaches incorporating partial derivatives, the peri-dynamic governing equations utilise integral expressions that remain valid in the presence of discontinuities such as cracks. The mathematical theory of peri-dynamics unifies the mechanics of continuous media, cracks, and discrete particles. The result is a consistent framework for capturing a wide range of constitutive responses, including inelasticity, in combination with robust material failure laws. Peri-dynamics has been implemented in a number of computational simulation codes, including the open source code Peridigm and the Sierra/SolidMechanics analysis code at Sandia National Laboratories. (author)

  3. Mercury's Dynamic Magnetosphere

    Science.gov (United States)

    Imber, S. M.

    2018-05-01

    The global dynamics of Mercury's magnetosphere will be discussed, focussing on observed asymmetries in the magnetotail and on the precipitation of particles of magnetospheric origin onto the nightside planetary surface.

  4. Market Squid Population Dynamics

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains population dynamics data on paralarvae, juvenile and adult market squid collected off California and the US Pacific Northwest. These data were...

  5. Gun Dynamics Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Gun Dynamics Laboratory is a research multi-task facility, which includes two firing bays, a high bay area and a second floor laboratory space. The high bay area...

  6. Dual Dynamic Programming - DDP

    International Nuclear Information System (INIS)

    Velasquez Bermudez, Jesus M

    1998-01-01

    Objections are presented to the mathematical formulation of the denominated Dual Dynamic programming-PDD that is the theoretical base of several computational model available for the optimal formulation of interconnected hydrothermal systems

  7. Controlling Uncertain Dynamical Systems

    Indian Academy of Sciences (India)

    Author Affiliations. N Ananthkrishnan1 Rashi Bansal2. Head, CAE Analysis & Design Zeus Numerix Pvt Ltd. M-03, SINE, IIT Bombay Powai Mumbai 400076, India. MTech (Aerospace Engineering) with specialization in Dynamics & Control from IIT Bombay.

  8. Instantaneous and dynamical decoherence

    Science.gov (United States)

    Polonyi, Janos

    2018-04-01

    Two manifestations of decoherence, called instantaneous and dynamical, are investigated. The former reflects the suppression of the interference between the components of the current state while the latter reflects that within the initial state. These types of decoherence are computed in the case of the Brownian motion and the harmonic and anharmonic oscillators within the semiclassical approximation. A remarkable phenomenon, namely the opposite orientation of the time arrow of the dynamical variables compared to that of the quantum fluctuations generates a double exponential time dependence of the dynamical decoherence in the presence of a harmonic force. For the weakly anharmonic oscillator the dynamical decoherence is found to depend in a singular way on the amount of the anharmonicity.

  9. Structural dynamic modification

    Indian Academy of Sciences (India)

    and stiffness matrices) andaor modal parameters, in order to acquire some ... For the above reasons, another modification approach is presented here ... The data necessary to solve the direct problem are dynamic behaviour of the original.

  10. Dynamics of interstellar matter

    International Nuclear Information System (INIS)

    Kahn, F.D.

    1975-01-01

    A review of the dynamics of interstellar matter is presented, considering the basic equations of fluid flow, plane waves, shock waves, spiral structure, thermal instabilities and early star cocoons. (B.R.H.)

  11. Fish population dynamics

    National Research Council Canada - National Science Library

    Gulland, J. A

    1977-01-01

    This book describes how the dynamics of fish populations can be analysed in terms of the factors affecting their rates of growth, mortality and reproduction, with particular emphasis on the effects of fishing...

  12. Dynamics of glassy systems

    International Nuclear Information System (INIS)

    Cugliandolo, Leticia F.

    2003-09-01

    These lecture notes can be read in two ways. The first two Sections contain a review of the phenomenology of several physical systems with slow nonequilibrium dynamics. In the Conclusions we summarize the scenario for this temporal evolution derived from the solution to some solvable models (p spin and the like) that are intimately connected to the mode coupling approach (and similar ones) to super-cooled liquids. At the end we list a number of open problems of great relevance in this context. These Sections can be read independently of the body of the paper where we present some of the basic analytic techniques used to study the out of equilibrium dynamics of classical and quantum models with and without disorder. We start the technical part by briefly discussing the role played by the environment and by introducing and comparing its representation in the equilibrium and dynamic treatment of classical and quantum systems. We next explain the role played by explicit quenched disorder in both approaches. Later on we focus on analytical techniques; we expand on the dynamic functional methods, and the diagrammatic expansions and resummations used to derive macroscopic equations from the microscopic dynamics. We show why the macroscopic dynamic equations for disordered models and those resulting from self-consistent approximations to non-disordered ones coincide. We review some generic properties of dynamic systems evolving out of equilibrium like the modifications of the fluctuation-dissipation theorem, generic scaling forms of the correlation functions, etc. Finally we solve a family of mean-field models. The connection between the dynamic treatment and the analysis of the free-energy landscape of these models is also presented. We use pedagogical examples all along these lectures to illustrate the properties and results. (author)

  13. Quantum net dynamics

    International Nuclear Information System (INIS)

    Finkelstein, D.

    1989-01-01

    The quantum net unifies the basic principles of quantum theory and relativity in a quantum spacetime having no ultraviolet infinities, supporting the Dirac equation, and having the usual vacuum as a quantum condensation. A correspondence principle connects nets to Schwinger sources and further unifies the vertical structure of the theory, so that the functions of the many hierarchic levels of quantum field theory (predicate algebra, set theory, topology,hor-ellipsis, quantum dynamics) are served by one in quantum net dynamics

  14. Dynamics of curved fronts

    CERN Document Server

    Pelce, Pierre

    1989-01-01

    In recent years, much progress has been made in the understanding of interface dynamics of various systems: hydrodynamics, crystal growth, chemical reactions, and combustion. Dynamics of Curved Fronts is an important contribution to this field and will be an indispensable reference work for researchers and graduate students in physics, applied mathematics, and chemical engineering. The book consist of a 100 page introduction by the editor and 33 seminal articles from various disciplines.

  15. Dynamic map labeling.

    Science.gov (United States)

    Been, Ken; Daiches, Eli; Yap, Chee

    2006-01-01

    We address the problem of filtering, selecting and placing labels on a dynamic map, which is characterized by continuous zooming and panning capabilities. This consists of two interrelated issues. The first is to avoid label popping and other artifacts that cause confusion and interrupt navigation, and the second is to label at interactive speed. In most formulations the static map labeling problem is NP-hard, and a fast approximation might have O(nlogn) complexity. Even this is too slow during interaction, when the number of labels shown can be several orders of magnitude less than the number in the map. In this paper we introduce a set of desiderata for "consistent" dynamic map labeling, which has qualities desirable for navigation. We develop a new framework for dynamic labeling that achieves the desiderata and allows for fast interactive display by moving all of the selection and placement decisions into the preprocessing phase. This framework is general enough to accommodate a variety of selection and placement algorithms. It does not appear possible to achieve our desiderata using previous frameworks. Prior to this paper, there were no formal models of dynamic maps or of dynamic labels; our paper introduces both. We formulate a general optimization problem for dynamic map labeling and give a solution to a simple version of the problem. The simple version is based on label priorities and a versatile and intuitive class of dynamic label placements we call "invariant point placements". Despite these restrictions, our approach gives a useful and practical solution. Our implementation is incorporated into the G-Vis system which is a full-detail dynamic map of the continental USA. This demo is available through any browser.

  16. Dynamical quantum teleportation

    Energy Technology Data Exchange (ETDEWEB)

    Muschik, Christine [ICFO-Institut de Ciencies Fotoniques (Spain); Polzik, Eugene [Niels Bohr Institute (Denmark); Cirac, Ignacio [Max-Planck-Institute (Germany)

    2013-07-01

    We introduce two protocols for inducing non-local dynamics between two separate parties. The first scheme allows for the engineering of an interaction between the two remote systems, while the second protocol induces a dynamics in one of the parties, which is controlled by the other one. Both schemes apply to continuous variable systems, run continuously in time and are based on instantaneous feedback.

  17. Dynamic Strategic Information Transmission

    OpenAIRE

    Mikhail Golosov; Vasiliki Skreta; Aleh Tsyvinski; Andrea Wilson

    2011-01-01

    This paper studies strategic information transmission in a dynamic environment where, each period, a privately informed expert sends a message and a decision maker takes an action. Our main result is that, in contrast to a static environment, full information revelation is possible. The gradual revelation of information and the eventual full revelation is supported by the dynamic rewards and punishments. The construction of a fully revealing equilibrium relies on two key features. The first f...

  18. Dynamics and causality constraints

    International Nuclear Information System (INIS)

    Sousa, Manoelito M. de

    2001-04-01

    The physical meaning and the geometrical interpretation of causality implementation in classical field theories are discussed. Causality in field theory are kinematical constraints dynamically implemented via solutions of the field equation, but in a limit of zero-distance from the field sources part of these constraints carries a dynamical content that explains old problems of classical electrodynamics away with deep implications to the nature of physicals interactions. (author)

  19. Dynamics of magnetospheric plasmas

    International Nuclear Information System (INIS)

    Horwitz, J.L.

    1985-01-01

    The dynamical behavior of the magnetospheric plasmas which control the electrostatic charging of spacecraft is the result of the complex interaction of a variety of production, loss, transport, and energization mechanisms in the magnetosphere. This paper is intended to provide the spacecraft engineer with a foundation in the basic morphology and controlling processes pertaining to magnetospheric plasma dynamics in the inner magnetosphere, including the synchronous orbit region. 32 references

  20. Channeling and dynamic chaos

    Energy Technology Data Exchange (ETDEWEB)

    Bolotin, IU L; Gonchar, V IU; Truten, V I; Shulga, N F

    1986-01-01

    It is shown that axial channeling of relativistic electrons can give rise to the effect of dynamic chaos which involves essentially chaotic motion of a particle in the channel. The conditions leading to the effect of dynamic chaos and the manifestations of this effect in physical processes associated with the passage of particles through a crystal are examined using a silicon crystal as an example. 7 references.

  1. Fusion-fission dynamics

    International Nuclear Information System (INIS)

    Blocki, J.; Planeta, R.; Brzychczyk, J.; Grotowski, K.

    1992-01-01

    Classical dynamical calculations of the heavy ion induced fission processes have been performed for the reactions 40 Ar+ 141 Pr, 20 Ne+ 165 Ho and 12 C+ 175 Lu leading to the iridium like nucleus. As a result prescission lifetimes were obtained and compared with the experimental values. The comparison between the calculated and experimental lifetimes indicates that the one-body dissipation picture is much more relevant in describing the fusion-fission dynamics than the two-body one. (orig.)

  2. Photochemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B.C. [Lawrence Berkeley Laboratory, Livermore, CA (United States)

    1993-12-01

    The purpose of the program is to develop a fundamental understanding of unimolecular and bimolecular reaction dynamics with application in combustion and energy systems. The energy dependence in ketene isomerization, ketene dissociation dynamics, and carbonyl substitution on organometallic rhodium complexes in liquid xenon have been studied. Future studies concerning unimolecular processes in ketene as well as energy transfer and kinetic studies of methylene radicals are discussed.

  3. Dynamics of Soft Matter

    CERN Document Server

    García Sakai, Victoria; Chen, Sow-Hsin

    2012-01-01

    Dynamics of Soft Matter: Neutron Applications provides an overview of neutron scattering techniques that measure temporal and spatial correlations simultaneously, at the microscopic and/or mesoscopic scale. These techniques offer answers to new questions arising at the interface of physics, chemistry, and biology. Knowledge of the dynamics at these levels is crucial to understanding the soft matter field, which includes colloids, polymers, membranes, biological macromolecules, foams, emulsions towards biological & biomimetic systems, and phenomena involving wetting, friction, adhesion, or micr

  4. The LHC dynamic aperture

    CERN Document Server

    Koutchouk, Jean-Pierre

    1999-01-01

    In 1996, the expected field errors in the dipoles and quadrupoles yielded a long-term dynamic aperture of some 8sigma at injection. The target was set to 12sigma to account for the limitations of our model (imperfections and dynamics). From scaling laws and tracking, a specification for the field imperfections yielding the target dynamic aperture was deduced. The gap between specification and expected errors is being bridged by i) an improvement of the dipole field quality, ii) a balance between geometric and persistent current errors, iii) additional correction circuits (a3 ,b4 ). With the goal in view, the emphasis has now turned to the sensitivity of the dynamic aperture to the optical parameters.The distortion of the dynamics at the lower amplitudes effectively reached by the particles is minimized by optimizing the distribution of the betatron phase advance. At collision energy, the dynamic aperture is limited by the field imperfections of the low-beta triplets, enhanced by the crossing angle. With corre...

  5. Dynamics in Complex Coacervates

    Science.gov (United States)

    Perry, Sarah

    Understanding the dynamics of a material provides detailed information about the self-assembly, structure, and intermolecular interactions present in a material. While rheological methods have long been used for the characterization of complex coacervate-based materials, it remains a challenge to predict the dynamics for a new system of materials. Furthermore, most work reports only qualitative trends exist as to how parameters such as charge stoichiometry, ionic strength, and polymer chain length impact self-assembly and material dynamics, and there is little information on the effects of polymer architecture or the organization of charges within a polymer. We seek to link thermodynamic studies of coacervation phase behavior with material dynamics through a carefully-controlled, systematic study of coacervate linear viscoelasticity for different polymer chemistries. We couple various methods of characterizing the dynamics of polymer-based complex coacervates, including the time-salt superposition methods developed first by Spruijt and coworkers to establish a more mechanistic strategy for comparing the material dynamics and linear viscoelasticity of different systems. Acknowledgment is made to the Donors of the American Chemical Society Petroleum Research Fund for support of this research.

  6. Offshore pipelaying dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Gullik Anthon

    2010-02-15

    This thesis considers three issues regarding modeling of of offshore pipe laying dynamics. These are: (i) the formulation of an offshore pipeline installation operation as a control problem, (ii) the development and passivity analysis of a robotic pipe model for a submerged pipe string, suitable for real-time applications in closed- loop control systems, and (iii) the development and validation of a nonlinear FEM model for simulation and control of the elastic pipeline dynamics, including FEM dynamics of a pipeline combined with vessel dynamics, for simulation and control of pipe lay operations under dynamic positioning Pipeline installation is defined as the operation of positioning a pipeline along a reference path on the seabed from a surface vessel. In control terms, this can be stated as a path-following control problem, where the pipe touchdown point tracks the reference path. However, the only controllers for the touchdown point are the pay-out of pipe into the water, and the motion of the surface vessel. Considering that the pipe is an elastic body, and that both the pipe and the vessel are subject to environmental loads, the control problem that must be considered is a dynamic target-tracking problem, where the surface vessel must track a moving target position on the surface in order to control the position of the touchdown point. A target-tracking controller may be implemented as a guidance system, by extending the dynamic positioning system that is common for pipe lay vessels. An important component in the guidance system is the dynamic pipe model mapping touchdown and surface vessel position. Motivated by robotics, a compact system formulation is derived for the suspended pipeline by considering it as a hyper-redundant manipulator with an arbitrary number of links. This model captures the main dynamics of the pipe, including its geometric configuration and top tension. The model is in the state- space, and on a vectorial form using minimal coordinates

  7. Summary: Hadron dynamics sessions

    International Nuclear Information System (INIS)

    Carroll, A.S.; Londergan, J.T.

    1993-01-01

    Four sessions on Hadron Dynamics were organized at this Workshop. The first topic, QCD Exclusive Reactions and Color Transparency, featured talks by Ralston, Heppelman and Strikman; the second, QCD and Inclusive Reactions had talks by Garvey, Speth and Kisslinger. The third dynamics session, Medium Modification of Elementary Interactions had contributions from Kopeliovich, Alves and Gyulassy; the fourth session Pre-QCD Dynamics and Scattering, had talks by Harris, Myhrer and Brown. An additional joint Spectroscopy/Dynamics session featured talks by Zumbro, Johnson and McClelland. These contributions are reviewed briefly in this summary. Two additional joint sessions between Dynamics and η physics are reviewed by the organizers of the Eta sessions. In such a brief review there is no way the authors can adequately summarize the details of the physics presented here. As a result, they concentrate only on brief impressionistic sketches of the physics topics discussed and their interrelations. They include no bibliography in this summary, but simply refer to the talks given in more detail in the Workshop proceedings. They focus on topics which were common to several presentations in these sessions. First, nuclear and particle descriptions of phenomena are now clearly converging, in both a qualitative and quantitative sense; they show several examples of this convergence. Second, an important issue in hadron dynamics is the extent to which elementary interactions are modified in nuclei at high energies and/or densities, and they illustrate some of these medium effects. Finally, they focus on those dynamical issues where hadron facilities can make an important, or even a unique, contribution to the knowledge of particle and nuclear physics

  8. Riverine habitat dynamics

    Science.gov (United States)

    Jacobson, R.B.

    2013-01-01

    The physical habitat template is a fundamental influence on riverine ecosystem structure and function. Habitat dynamics refers to the variation in habitat through space and time as the result of varying discharge and varying geomorphology. Habitat dynamics can be assessed at spatial scales ranging from the grain (the smallest resolution at which an organism relates to its environment) to the extent (the broadest resolution inclusive of all space occupied during its life cycle). In addition to a potentially broad range of spatial scales, assessments of habitat dynamics may include dynamics of both occupied and nonoccupied habitat patches because of process interactions among patches. Temporal aspects of riverine habitat dynamics can be categorized into hydrodynamics and morphodynamics. Hydrodynamics refers to habitat variation that results from changes in discharge in the absence of significant change of channel morphology and at generally low sediment-transport rates. Hydrodynamic assessments are useful in cases of relatively high flow exceedance (percent of time a flow is equaled or exceeded) or high critical shear stress, conditions that are applicable in many studies of instream flows. Morphodynamics refers to habitat variation resulting from changes to substrate conditions or channel/floodplain morphology. Morphodynamic assessments are necessary when channel and floodplain boundary conditions have been significantly changed, generally by relatively rare flood events or in rivers with low critical shear stress. Morphodynamic habitat variation can be particularly important as disturbance mechanisms that mediate population growth or for providing conditions needed for reproduction, such as channel-migration events that erode cutbanks and provide new pointbar surfaces for germination of riparian trees. Understanding of habitat dynamics is increasing in importance as societal goals shift toward restoration of riverine ecosystems. Effective investment in restoration

  9. Dynamic wall demonstration project

    Energy Technology Data Exchange (ETDEWEB)

    Nakatsui, L.; Mayhew, W.

    1990-12-01

    The dynamic wall concept is a ventilation strategy that can be applied to a single family dwelling. With suitable construction, outside air can be admitted through the exterior walls of the house to the interior space to function as ventilation air. The construction and performance monitoring of a demonstration house built to test the dynamic wall concept in Sherwood Park, Alberta, is described. The project had the objectives of demonstrating and assessing the construction methods; determining the cost-effectiveness of the concept in Alberta; analyzing the operation of the dynamic wall system; and determining how other components and systems in the house interact with the dynamic wall. The exterior wall construction consisted of vinyl siding, spun-bonded polyolefin-backed (SBPO) rigid fiberglass sheathing, 38 mm by 89 mm framing, fiberglass batt insulation and 12.7 mm drywall. The mechanical system was designed to operate in the dynamic (negative pressure) mode, however flexibility was provided to allow operation in the static (balanced pressure) mode to permit monitoring of the walls as if they were in a conventional house. The house was monitored by an extensive computerized monitoring system. Dynamic wall operation was dependent on pressure and temperature differentials between indoor and outdoor as well as wind speed and direction. The degree of heat gain was found to be ca 74% of the indoor-outdoor temperature differential. Temperature of incoming dynamic air was significantly affected by solar radiation and measurement of indoor air pollutants found no significant levels. 4 refs., 34 figs., 11 tabs.

  10. Astrophysical fluid dynamics

    Science.gov (United States)

    Ogilvie, Gordon I.

    2016-06-01

    > These lecture notes and example problems are based on a course given at the University of Cambridge in Part III of the Mathematical Tripos. Fluid dynamics is involved in a very wide range of astrophysical phenomena, such as the formation and internal dynamics of stars and giant planets, the workings of jets and accretion discs around stars and black holes and the dynamics of the expanding Universe. Effects that can be important in astrophysical fluids include compressibility, self-gravitation and the dynamical influence of the magnetic field that is `frozen in' to a highly conducting plasma. The basic models introduced and applied in this course are Newtonian gas dynamics and magnetohydrodynamics (MHD) for an ideal compressible fluid. The mathematical structure of the governing equations and the associated conservation laws are explored in some detail because of their importance for both analytical and numerical methods of solution, as well as for physical interpretation. Linear and nonlinear waves, including shocks and other discontinuities, are discussed. The spherical blast wave resulting from a supernova, and involving a strong shock, is a classic problem that can be solved analytically. Steady solutions with spherical or axial symmetry reveal the physics of winds and jets from stars and discs. The linearized equations determine the oscillation modes of astrophysical bodies, as well as their stability and their response to tidal forcing.

  11. Emergence in Dynamical Systems

    Directory of Open Access Journals (Sweden)

    John Collier

    2013-12-01

    Full Text Available Emergence is a term used in many contexts in current science; it has become fashionable. It has a traditional usage in philosophy that started in 1875 and was expanded by J. S. Mill (earlier, under a different term and C. D. Broad. It is this form of emergence that I am concerned with here. I distinguish it from uses like ‘computational emergence,’ which can be reduced to combinations of program steps, or its application to merely surprising new features that appear in complex combinations of parts. I will be concerned specifically with ontological emergence that has the logical properties required by Mill and Broad (though there might be some quibbling about the details of their views. I restrict myself to dynamical systems that are embodied in processes. Everything that we can interact with through sensation or action is either dynamical or can be understood in dynamical terms, so this covers all comprehensible forms of emergence in the strong (nonreducible sense I use. I will give general dynamical conditions that underlie the logical conditions traditionally assigned to emergence in nature.The advantage of this is that, though we cannot test logical conditions directly, we can test dynamical conditions. This gives us an empirical and realistic form of emergence, contrary those who say it is a matter of perspective.

  12. Modeling dynamic swarms

    KAUST Repository

    Ghanem, Bernard

    2013-01-01

    This paper proposes the problem of modeling video sequences of dynamic swarms (DSs). We define a DS as a large layout of stochastically repetitive spatial configurations of dynamic objects (swarm elements) whose motions exhibit local spatiotemporal interdependency and stationarity, i.e., the motions are similar in any small spatiotemporal neighborhood. Examples of DS abound in nature, e.g., herds of animals and flocks of birds. To capture the local spatiotemporal properties of the DS, we present a probabilistic model that learns both the spatial layout of swarm elements (based on low-level image segmentation) and their joint dynamics that are modeled as linear transformations. To this end, a spatiotemporal neighborhood is associated with each swarm element, in which local stationarity is enforced both spatially and temporally. We assume that the prior on the swarm dynamics is distributed according to an MRF in both space and time. Embedding this model in a MAP framework, we iterate between learning the spatial layout of the swarm and its dynamics. We learn the swarm transformations using ICM, which iterates between estimating these transformations and updating their distribution in the spatiotemporal neighborhoods. We demonstrate the validity of our method by conducting experiments on real and synthetic video sequences. Real sequences of birds, geese, robot swarms, and pedestrians evaluate the applicability of our model to real world data. © 2012 Elsevier Inc. All rights reserved.

  13. More dynamical supersymmetry breaking

    International Nuclear Information System (INIS)

    Csaki, C.; Randall, L.; Skiba, W.

    1996-01-01

    In this paper we introduce a new class of theories which dynamically break supersymmetry based on the gauge group SU(n) x SU(3) x U(1) for even n. These theories are interesting in that no dynamical superpotential is generated in the absence of perturbations. For the example SU(4) x SU(3) x U(1) we explicitly demonstrate that all flat directions can be lifted through a renormalizable superpotential and that supersymmetry is dynamically broken. We derive the exact superpotential for this theory, which exhibits new and interesting dynamical phenomena. For example, modifications to classical constraints can be field dependent. We also consider the generalization to SU(n) x SU(3) x U(1) models (with even n>4). We present a renormalizable superpotential which lifts all flat directions. Because SU(3) is not confining in the absence of perturbations, the analysis of supersymmetry breaking is very different in these theories from the n=4 example. When the SU(n) gauge group confines, the Yukawa couplings drive the SU(3) theory into a regime with a dynamically generated superpotential. By considering a simplified version of these theories we argue that supersymmetry is probably broken. (orig.)

  14. System dynamics with interaction discontinuity

    CERN Document Server

    Luo, Albert C J

    2015-01-01

    This book describes system dynamics with discontinuity caused by system interactions and presents the theory of flow singularity and switchability at the boundary in discontinuous dynamical systems. Based on such a theory, the authors address dynamics and motion mechanism of engineering discontinuous systems due to interaction. Stability and bifurcations of fixed points in nonlinear discrete dynamical systems are presented, and mapping dynamics are developed for analytical predictions of periodic motions in engineering discontinuous dynamical systems. Ultimately, the book provides an alternative way to discuss the periodic and chaotic behaviors in discontinuous dynamical systems.

  15. Vehicle dynamics theory and application

    CERN Document Server

    Jazar, Reza N

    2017-01-01

    This intermediate textbook is appropriate for students in vehicle dynamics courses, in their last year of undergraduate study or their first year of graduate study. It is also appropriate for mechanical engineers, automotive engineers, and researchers in the area of vehicle dynamics for continuing education or as a reference. It addresses fundamental and advanced topics, and a basic knowledge of kinematics and dynamics, as well as numerical methods, is expected. The contents are kept at a theoretical-practical level, with a strong emphasis on application. This third edition has been reduced by 25%, to allow for coverage over one semester, as opposed to the previous edition that needed two semesters for coverage. The textbook is composed of four parts: Vehicle Motion: covers tire dynamics, forward vehicle dynamics, and driveline dynamics Vehicle Kinematics: covers applied kinematics, applied mechanisms, steering dynamics, and suspension mechanisms Vehicle Dynamics: covers applied dynamics, vehicle planar dynam...

  16. Dynamics in geometrical confinement

    CERN Document Server

    Kremer, Friedrich

    2014-01-01

    This book describes the dynamics of low molecular weight and polymeric molecules when they are constrained under conditions of geometrical confinement. It covers geometrical confinement in different dimensionalities: (i) in nanometer thin layers or self supporting films (1-dimensional confinement) (ii) in pores or tubes with nanometric diameters (2-dimensional confinement) (iii) as micelles embedded in matrices (3-dimensional) or as nanodroplets.The dynamics under such conditions have been a much discussed and central topic in the focus of intense worldwide research activities within the last two decades. The present book discusses how the resulting molecular mobility is influenced by the subtle counterbalance between surface effects (typically slowing down molecular dynamics through attractive guest/host interactions) and confinement effects (typically increasing the mobility). It also explains how these influences can be modified and tuned, e.g. through appropriate surface coatings, film thicknesses or pore...

  17. Stochastic ice stream dynamics.

    Science.gov (United States)

    Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-08-09

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

  18. Introduction to dynamics

    CERN Document Server

    Pfeiffer, Friedrich

    2015-01-01

    This concise textbook for students preferably of a postgraduate level, but also for engineers in practice, contains the basic kinematical and kinetic structures of dynamics together with carefully selected applications. The book is a condensed introduction to the fundamental laws of kinematics and kinetics, on the most important principles of mechanics and presents the equations of motion in the form of Lagrange and Newton-Euler. Selected problems of linear and nonlinear dynamics are treated, as well as problems of vibration formation. The presented selection of topics gives a useful basis for stepping into more advanced problems of dynamics. The contents of this book represent the result of a regularly revised course, which has been and still is given for masters students at the Technische Universität München. .

  19. Dynamic Global Currency Hedging

    DEFF Research Database (Denmark)

    Christensen, Bent Jesper; Varneskov, Rasmus T.

    2016-01-01

    This paper proposes a model for discrete-time hedging based on continuous-time movements in portfolio and foreign currency exchange rate returns. In particular, the vector of optimal currency exposures is shown to be given by the negative realized regression coefficients from a one......-period conditional expectation of the intra-period quadratic covariation matrix for portfolio and foreign exchange rate returns. These are labelled the realized currency betas. The model, hence, facilitates dynamic hedging strategies that depend exclusively on the dynamic evolution of the ex-post quadratic...... covariation matrix. These hedging strategies are suggested implemented using modern, yet simple, non-parametric techniques to accurately measure and dynamically model historical quadratic covariation matrices. The empirical results from an extensive hedging exercise for equity investments illustrate...

  20. Butschli Dynamic Droplet System

    DEFF Research Database (Denmark)

    Armstrong, R.; Hanczyc, M.

    2013-01-01

    Dynamical oil-water systems such as droplets display lifelike properties and may lend themselves to chemical programming to perform useful work, specifically with respect to the built environment. We present Butschli water-in-oil droplets as a model for further investigation into the development...... reconstructed the Butschli system and observed its life span under a light microscope, observing chemical patterns and droplet behaviors in nearly three hundred replicate experiments. Self-organizing patterns were observed, and during this dynamic, embodied phase the droplets provided a means of introducing...... temporal and spatial order in the system with the potential for chemical programmability. The authors propose that the discrete formation of dynamic droplets, characterized by their lifelike behavior patterns, during a variable window of time (from 30 s to 30 min after the addition of alkaline water...

  1. Coherent dynamics in semiconductors

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher

    1998-01-01

    enhanced in quantum confined lower-dimensional systems, where exciton and biexciton effects dominate the spectra even at room temperature. The coherent dynamics of excitons are at modest densities well described by the optical Bloch equations and a number of the dynamical effects known from atomic......Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

  2. Vorticity and vortex dynamics

    CERN Document Server

    Wu, Jie-Zhi; Zhou, M-D

    2006-01-01

    The importance of vorticity and vortex dynamics has now been well rec- nized at both fundamental and applied levels of ?uid dynamics, as already anticipatedbyTruesdellhalfcenturyagowhenhewrotethe?rstmonograph onthesubject, The Kinematics of Vorticity(1954);andasalsoevidencedby the appearance of several books on this ?eld in 1990s. The present book is characterizedbythefollowingfeatures: 1. A basic physical guide throughout the book. The material is directed by a basic observation on the splitting and coupling of two fundamental processes in ?uid motion, i.e., shearing (unique to ?uid) and compre- ing/expanding.Thevorticityplaysakeyroleintheformer,andavortex isnothingbuta?uidbodywithhighconcentrationofvorticitycompared to its surrounding ?uid. Thus, the vorticity and vortex dynamics is - cordinglyde?nedasthetheoryofshearingprocessanditscouplingwith compressing/expandingprocess. 2. A description of the vortex evolution following its entire life.Thisbegins from the generation of vorticity to the formation of thi...

  3. Lagrangian and Hamiltonian dynamics

    CERN Document Server

    Mann, Peter

    2018-01-01

    An introductory textbook exploring the subject of Lagrangian and Hamiltonian dynamics, with a relaxed and self-contained setting. Lagrangian and Hamiltonian dynamics is the continuation of Newton's classical physics into new formalisms, each highlighting novel aspects of mechanics that gradually build in complexity to form the basis for almost all of theoretical physics. Lagrangian and Hamiltonian dynamics also acts as a gateway to more abstract concepts routed in differential geometry and field theories and can be used to introduce these subject areas to newcomers. Journeying in a self-contained manner from the very basics, through the fundamentals and onwards to the cutting edge of the subject, along the way the reader is supported by all the necessary background mathematics, fully worked examples, thoughtful and vibrant illustrations as well as an informal narrative and numerous fresh, modern and inter-disciplinary applications. The book contains some unusual topics for a classical mechanics textbook. Mo...

  4. Predictability in community dynamics.

    Science.gov (United States)

    Blonder, Benjamin; Moulton, Derek E; Blois, Jessica; Enquist, Brian J; Graae, Bente J; Macias-Fauria, Marc; McGill, Brian; Nogué, Sandra; Ordonez, Alejandro; Sandel, Brody; Svenning, Jens-Christian

    2017-03-01

    The coupling between community composition and climate change spans a gradient from no lags to strong lags. The no-lag hypothesis is the foundation of many ecophysiological models, correlative species distribution modelling and climate reconstruction approaches. Simple lag hypotheses have become prominent in disequilibrium ecology, proposing that communities track climate change following a fixed function or with a time delay. However, more complex dynamics are possible and may lead to memory effects and alternate unstable states. We develop graphical and analytic methods for assessing these scenarios and show that these dynamics can appear in even simple models. The overall implications are that (1) complex community dynamics may be common and (2) detailed knowledge of past climate change and community states will often be necessary yet sometimes insufficient to make predictions of a community's future state. © 2017 John Wiley & Sons Ltd/CNRS.

  5. Fractional Dynamics and Control

    CERN Document Server

    Machado, José; Luo, Albert

    2012-01-01

    Fractional Dynamics and Control provides a comprehensive overview of recent advances in the areas of nonlinear dynamics, vibration and control with analytical, numerical, and experimental results. This book provides an overview of recent discoveries in fractional control, delves into fractional variational principles and differential equations, and applies advanced techniques in fractional calculus to solving complicated mathematical and physical problems.Finally, this book also discusses the role that fractional order modeling can play in complex systems for engineering and science. Discusses how fractional dynamics and control can be used to solve nonlinear science and complexity issues Shows how fractional differential equations and models can be used to solve turbulence and wave equations in mechanics and gravity theories and Schrodinger’s equation  Presents factional relaxation modeling of dielectric materials and wave equations for dielectrics  Develops new methods for control and synchronization of...

  6. Dynamical symmetries for fermions

    International Nuclear Information System (INIS)

    Guidry, M.

    1989-01-01

    An introduction is given to the Fermion Dynamical Symmetry Model (FDSM). The analytical symmetry limits of the model are then applied to the calculation of physical quantities such as ground-state masses and B(E 2 ) values in heavy nuclei. These comparisons with data provide strong support for a new principle of collective motion, the Dynamical Pauli Effect, and suggest that dynamical symmetries which properly account for the pauli principle are much more persistent in nuclear structure than the corresponding boson symmetries. Finally, we present an assessment of criticisms which have been voiced concerning the FDSM, and a discussion of new phenomena and ''exotic spectroscopy'' which may be suggested by the model. 14 refs., 8 figs., 4 tabs

  7. Conference on Multibody Dynamics

    CERN Document Server

    Multibody Dynamics : Computational Methods and Applications

    2014-01-01

    By having its origin in analytical and continuum mechanics, as well as in computer science and applied mathematics, multibody dynamics provides a basis for analysis and virtual prototyping of innovative applications in many fields of contemporary engineering. With the utilization of computational models and algorithms that classically belonged to different fields of applied science, multibody dynamics delivers reliable simulation platforms for diverse highly-developed industrial products such as vehicle and railway systems, aeronautical and space vehicles, robotic manipulators, smart structures, biomechanical applications and nano-technologies. The chapters of this volume are based on the revised and extended versions of the selected scientific papers from amongst 255 original contributions that have been accepted to be presented within the program of the distinguished international ECCOMAS conference. It reflects state-of-the-art in the advances of multibody dynamics, providing excellent insight in the recen...

  8. What are System Dynamics Insights?

    OpenAIRE

    Stave, K.; Zimmermann, N. S.; Kim, H.

    2016-01-01

    This paper explores the concept of system dynamics insights. In our field, the term “insight” is generally understood to mean dynamic insight, that is, a deep understanding about the relationship between structure and behavior. We argue this is only one aspect of the range of insights possible from system dynamics activities, and describe a broader range of potential system dynamics insights. We also propose an initial framework for discussion that relates different types of system dynamics a...

  9. Dynamically Assisted Schwinger Mechanism

    International Nuclear Information System (INIS)

    Schuetzhold, Ralf; Gies, Holger; Dunne, Gerald

    2008-01-01

    We study electron-positron pair creation from the Dirac vacuum induced by a strong and slowly varying electric field (Schwinger effect) which is superimposed by a weak and rapidly changing electromagnetic field (dynamical pair creation). In the subcritical regime where both mechanisms separately are strongly suppressed, their combined impact yields a pair creation rate which is dramatically enhanced. Intuitively speaking, the strong electric field lowers the threshold for dynamical particle creation--or, alternatively, the fast electromagnetic field generates additional seeds for the Schwinger mechanism. These findings could be relevant for planned ultrahigh intensity lasers

  10. Models for Dynamic Applications

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Morales Rodriguez, Ricardo; Heitzig, Martina

    2011-01-01

    This chapter covers aspects of the dynamic modelling and simulation of several complex operations that include a controlled blending tank, a direct methanol fuel cell that incorporates a multiscale model, a fluidised bed reactor, a standard chemical reactor and finally a polymerisation reactor...... be applied to formulate, analyse and solve these dynamic problems and how in the case of the fuel cell problem the model consists of coupledmeso and micro scale models. It is shown how data flows are handled between the models and how the solution is obtained within the modelling environment....

  11. Dynamics of structures

    CERN Document Server

    Paultre, Patrick

    2013-01-01

    This book covers structural dynamics from a theoretical and algorithmic approach. It covers systems with both single and multiple degrees-of-freedom. Numerous case studies are given to provide the reader with a deeper insight into the practicalities of the area, and the solutions to these case studies are given in terms of real-time and frequency in both geometric and modal spaces. Emphasis is also given to the subject of seismic loading. The text is based on many lectures on the subject of structural dynamics given at numerous institutions and thus will be an accessible and practical aid to

  12. Dynamics in artifact ecologies

    DEFF Research Database (Denmark)

    Bødker, Susanne; Klokmose, Clemens Nylandsted

    2012-01-01

    We increasingly interact with multiple interactive artifacts with overlapping capabilities during our daily activities. It has previously been shown that the use of an interactive artifact cannot be understood in isolation, but artifacts must be understood as part of an artifact ecology, where...... artifacts influence the use of others. Understanding this interplay becomes more and more essential for interaction design as our artifact ecologies grow. This paper continues a recent discourse on artifact ecologies. Through interviews with iPhone users, we demonstrate that relationships between artifacts...... in artifact ecologies cannot be understood as static, instead they evolve dynamically over time. We provide activity theory-based concepts to explain these dynamics....

  13. Dynamic gamma knife radiosurgery

    International Nuclear Information System (INIS)

    Luan Shuang; Swanson, Nathan; Chen Zhe; Ma Lijun

    2009-01-01

    Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C(TM) and Perfexion(TM) units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can obtain a family of plans representing a tradeoff between the delivery time and

  14. Stochastic Switching Dynamics

    DEFF Research Database (Denmark)

    Simonsen, Maria

    This thesis treats stochastic systems with switching dynamics. Models with these characteristics are studied from several perspectives. Initially in a simple framework given in the form of stochastic differential equations and, later, in an extended form which fits into the framework of sliding...... mode control. It is investigated how to understand and interpret solutions to models of switched systems, which are exposed to discontinuous dynamics and uncertainties (primarily) in the form of white noise. The goal is to gain knowledge about the performance of the system by interpreting the solution...

  15. Dynamics of Catalyst Nanoparticles

    DEFF Research Database (Denmark)

    Hansen, Thomas Willum; Cavalca, Filippo; Wagner, Jakob Birkedal

    and pharmaceuticals, and the cleanup of exhaust from automobiles and stationary power plants. Sintering, or thermal deactivation, is an important mechanism for the loss of catalyst activity. In order to initiate a systematic study of the dynamics and sintering of nanoparticles, various catalytic systems have been...... under gas exposure, dynamic phenomena such as sintering and growth can be observed with sub-Ångstrøm resolution. Metal nanoparticles contain the active sites in heterogeneous catalysts, which are important for many industrial applications including the production of clean fuels, chemicals...

  16. Safe Dynamic Multiple Inheritance

    DEFF Research Database (Denmark)

    Ernst, Erik

    2002-01-01

    Multiple inheritance and similar mechanisms are usually only supported at compile time in statically typed languages. Nevertheless, dynamic multiple inheritance would be very useful in the development of complex systems, because it allows the creation of many related classes without an explosion...... in the size and level of redundancy in the source code. In fact, dynamic multiple inheritance is already available. The language gbeta is statically typed and has supported run-time combination of classes and methods since 1997, by means of the combination operator '&'. However, with certain combinations...

  17. Fundamental composite electroweak dynamics

    DEFF Research Database (Denmark)

    Arbey, Alexandre; Cacciapaglia, Giacomo; Cai, Haiying

    2017-01-01

    Using the recent joint results from the ATLAS and CMS collaborations on the Higgs boson, we determine the current status of composite electroweak dynamics models based on the expected scalar sector. Our analysis can be used as a minimal template for a wider class of models between the two limitin...... space at the effective Lagrangian level. We show that a wide class of models of fundamental composite electroweak dynamics are still compatible with the present constraints. The results are relevant for the ongoing and future searches at the Large Hadron Collider....

  18. Introduction to cluster dynamics

    CERN Document Server

    Reinhard, Paul-Gerhard

    2008-01-01

    Clusters as mesoscopic particles represent an intermediate state of matter between single atoms and solid material. The tendency to miniaturise technical objects requires knowledge about systems which contain a ""small"" number of atoms or molecules only. This is all the more true for dynamical aspects, particularly in relation to the qick development of laser technology and femtosecond spectroscopy. Here, for the first time is a highly qualitative introduction to cluster physics. With its emphasis on cluster dynamics, this will be vital to everyone involved in this interdisciplinary subje

  19. Spectrally accurate contour dynamics

    International Nuclear Information System (INIS)

    Van Buskirk, R.D.; Marcus, P.S.

    1994-01-01

    We present an exponentially accurate boundary integral method for calculation the equilibria and dynamics of piece-wise constant distributions of potential vorticity. The method represents contours of potential vorticity as a spectral sum and solves the Biot-Savart equation for the velocity by spectrally evaluating a desingularized contour integral. We use the technique in both an initial-value code and a newton continuation method. Our methods are tested by comparing the numerical solutions with known analytic results, and it is shown that for the same amount of computational work our spectral methods are more accurate than other contour dynamics methods currently in use

  20. DYNAMIC LOAD DAMPER MODELING

    Directory of Open Access Journals (Sweden)

    Loktev Aleksey Alekseevich

    2013-01-01

    Full Text Available The authors present their findings associated with their modeling of a dynamic load damper. According to the authors, the damper is to be installed onto a structure or its element that may be exposed to impact, vibration or any other dynamic loading. The damper is composed of paralleled or consecutively connected viscous and elastic elements. The authors study the influence of viscosity and elasticity parameters of the damper produced onto the regular displacement of points of the structure to be protected and onto the regular acceleration transmitted immediately from the damper to the elements positioned below it.

  1. Fluid Dynamics for Physicists

    Science.gov (United States)

    Faber, T. E.

    1995-08-01

    This textbook provides an accessible and comprehensive account of fluid dynamics that emphasizes fundamental physical principles and stresses connections with other branches of physics. Beginning with a basic introduction, the book goes on to cover many topics not typically treated in texts, such as compressible flow and shock waves, sound attenuation and bulk viscosity, solitary waves and ship waves, thermal convection, instabilities, turbulence, and the behavior of anisotropic, non-Newtonian and quantum fluids. Undergraduate or graduate students in physics or engineering who are taking courses in fluid dynamics will find this book invaluable.

  2. Maya Studio Projects Dynamics

    CERN Document Server

    Palamar, Todd

    2009-01-01

    The only hands-on book devoted to mastering Maya's dynamics tools for water, wind, and fire. In the world of animation, the ability to create realistic water, wind, and fire effects is key. Autodesk Maya software includes powerful dynamics tools that have been used to design breathtaking effects for movies, games, commercials, and short films. This professional guide teaches you the primary techniques you need to make the most of Maya's toolkit, so you'll soon be creating water that ripples, gusting winds and gentle breezes, and flickering fires the way Hollywood pros do. The one-of-a-kind boo

  3. Substructured multibody molecular dynamics.

    Energy Technology Data Exchange (ETDEWEB)

    Grest, Gary Stephen; Stevens, Mark Jackson; Plimpton, Steven James; Woolf, Thomas B. (Johns Hopkins University, Baltimore, MD); Lehoucq, Richard B.; Crozier, Paul Stewart; Ismail, Ahmed E.; Mukherjee, Rudranarayan M. (Rensselaer Polytechnic Institute, Troy, NY); Draganescu, Andrei I.

    2006-11-01

    We have enhanced our parallel molecular dynamics (MD) simulation software LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator, lammps.sandia.gov) to include many new features for accelerated simulation including articulated rigid body dynamics via coupling to the Rensselaer Polytechnic Institute code POEMS (Parallelizable Open-source Efficient Multibody Software). We use new features of the LAMMPS software package to investigate rhodopsin photoisomerization, and water model surface tension and capillary waves at the vapor-liquid interface. Finally, we motivate the recipes of MD for practitioners and researchers in numerical analysis and computational mechanics.

  4. Complexified dynamical systems

    International Nuclear Information System (INIS)

    Bender, Carl M; Holm, Darryl D; Hook, Daniel W

    2007-01-01

    Many dynamical systems, such as the Lotka-Volterra predator-prey model and the Euler equations for the free rotation of a rigid body, are PT symmetric. The standard and well-known real solutions to such dynamical systems constitute an infinitessimal subclass of the full set of complex solutions. This paper examines a subset of the complex solutions that contains the real solutions, namely those having PT symmetry. The condition of PT symmetry selects out complex solutions that are periodic. (fast track communication)

  5. Dynamic gamma knife radiosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Luan Shuang; Swanson, Nathan; Chen Zhe [Department of Computer Science, University of New Mexico, Albuquerque, NM 87131 (United States); Ma Lijun [Department of Radiation Oncology, University of California San Francisco, San Francisco, CA 94143 (United States)], E-mail: sluan@cs.unm.edu, E-mail: nate@cs.unm.edu, E-mail: zchen@cs.unm.edu, E-mail: lijunma@radonc.ucsf.edu

    2009-03-21

    Gamma knife has been the treatment of choice for various brain tumors and functional disorders. Current gamma knife radiosurgery is planned in a 'ball-packing' approach and delivered in a 'step-and-shoot' manner, i.e. it aims to 'pack' the different sized spherical high-dose volumes (called 'shots') into a tumor volume. We have developed a dynamic scheme for gamma knife radiosurgery based on the concept of 'dose-painting' to take advantage of the new robotic patient positioning system on the latest Gamma Knife C(TM) and Perfexion(TM) units. In our scheme, the spherical high dose volume created by the gamma knife unit will be viewed as a 3D spherical 'paintbrush', and treatment planning reduces to finding the best route of this 'paintbrush' to 'paint' a 3D tumor volume. Under our dose-painting concept, gamma knife radiosurgery becomes dynamic, where the patient moves continuously under the robotic positioning system. We have implemented a fully automatic dynamic gamma knife radiosurgery treatment planning system, where the inverse planning problem is solved as a traveling salesman problem combined with constrained least-square optimizations. We have also carried out experimental studies of dynamic gamma knife radiosurgery and showed the following. (1) Dynamic gamma knife radiosurgery is ideally suited for fully automatic inverse planning, where high quality radiosurgery plans can be obtained in minutes of computation. (2) Dynamic radiosurgery plans are more conformal than step-and-shoot plans and can maintain a steep dose gradient (around 13% per mm) between the target tumor volume and the surrounding critical structures. (3) It is possible to prescribe multiple isodose lines with dynamic gamma knife radiosurgery, so that the treatment can cover the periphery of the target volume while escalating the dose for high tumor burden regions. (4) With dynamic gamma knife radiosurgery, one can

  6. Dynamics on Lorentz manifolds

    CERN Document Server

    Adams, Scot

    2001-01-01

    Within the general framework of the dynamics of "large" groups on geometric spaces, the focus is on the types of groups that can act in complicated ways on Lorentz manifolds, and on the structure of the resulting manifolds and actions. This particular area of dynamics is an active one, and not all the results are in their final form. However, at this point, a great deal can be said about the particular Lie groups that come up in this context. It is impressive that, even assuming very weak recurrence of the action, the list of possible groups is quite restricted. For the most complicated of the

  7. Nonuniversal disordered Glauber dynamics.

    Science.gov (United States)

    Grynberg, Marcelo D; Stinchcombe, Robin B

    2013-06-01

    We consider the one-dimensional Glauber dynamics with coupling disorder in terms of bilinear fermion Hamiltonians. Dynamic exponents embodied in the spectrum gap of these latter are evaluated numerically by averaging over both binary and Gaussian disorder realizations. In the first case, these exponents are found to follow the nonuniversal values of those of plain dimerized chains. In the second situation their values are still nonuniversal and subdiffusive below a critical variance above which, however, the relaxation time is suggested to grow as a stretched exponential of the equilibrium correlation length.

  8. Principles of dynamics

    CERN Document Server

    Hill, Rodney

    2013-01-01

    Principles of Dynamics presents classical dynamics primarily as an exemplar of scientific theory and method. This book is divided into three major parts concerned with gravitational theory of planetary systems; general principles of the foundations of mechanics; and general motion of a rigid body. Some of the specific topics covered are Keplerian Laws of Planetary Motion; gravitational potential and potential energy; and fields of axisymmetric bodies. The principles of work and energy, fictitious body-forces, and inertial mass are also looked into. Other specific topics examined are kinematics

  9. Dynamic planar embeddings of dynamic graphs

    DEFF Research Database (Denmark)

    Holm, Jacob; Rotenberg, Eva

    2015-01-01

    -flip-linkable(u, v) providing a suggestion for a flip that will make them linkable if one exists. We will support all updates and queries in O(log2 n) time. Our time bounds match those of Italiano et al. for a static (flipless) embedding of a dynamic graph. Our new algorithm is simpler, exploiting...... that the complement of a spanning tree of a connected plane graph is a spanning tree of the dual graph. The primal and dual trees are interpreted as having the same Euler tour, and a main idea of the new algorithm is an elegant interaction between top trees over the two trees via their common Euler tour....

  10. Dynamic planar embeddings of dynamic graphs

    DEFF Research Database (Denmark)

    Holm, Jacob; Rotenberg, Eva

    2017-01-01

    query, one-flip- linkable(u,v) providing a suggestion for a flip that will make them linkable if one exists. We support all updates and queries in O(log 2 n) time. Our time bounds match those of Italiano et al. for a static (flipless) embedding of a dynamic graph. Our new algorithm is simpler......, exploiting that the complement of a spanning tree of a connected plane graph is a spanning tree of the dual graph. The primal and dual trees are interpreted as having the same Euler tour, and a main idea of the new algorithm is an elegant interaction between top trees over the two trees via their common...

  11. Dynamic Analysis of a Pendulum Dynamic Automatic Balancer

    Directory of Open Access Journals (Sweden)

    Jin-Seung Sohn

    2007-01-01

    Full Text Available The automatic dynamic balancer is a device to reduce the vibration from unbalanced mass of rotors. Instead of considering prevailing ball automatic dynamic balancer, pendulum automatic dynamic balancer is analyzed. For the analysis of dynamic stability and behavior, the nonlinear equations of motion for a system are derived with respect to polar coordinates by the Lagrange's equations. The perturbation method is applied to investigate the dynamic behavior of the system around the equilibrium position. Based on the linearized equations, the dynamic stability of the system around the equilibrium positions is investigated by the eigenvalue analysis.

  12. Dynamic Systems and Software

    DEFF Research Database (Denmark)

    Thomsen, Per Grove

    1996-01-01

    A one-dimensional model with axial discretization of engine components has been formulated using tha balance equations for mass energy and momentum and the ideal gas equation of state. ODE's that govern the dynamic behaviour of the regenerator matrix temperatures are included in the model. Known...

  13. PELE fragmentation dynamics

    NARCIS (Netherlands)

    Verreault, J.; Hinsberg, N.P. van; Abadjieva, E.

    2013-01-01

    An analytical model that describes the PELE fragmentation dynamics is presented and compared with experimental results from literature. The model accounts for strong shock effects and detailed interactions taking place between the filling – the inner core of the ammunition – and the target

  14. Rf quadrupole beam dynamics

    International Nuclear Information System (INIS)

    Stokes, R.H.; Crandall, K.R.; Stovall, J.E.; Swenson, D.A.

    1979-01-01

    A method has been developed to analyze the beam dynamics of the radiofrequency quadrupole accelerating structure. Calculations show that this structure can accept a dc beam at low velocity, bunch it with high capture efficiency, and accelerate it to a velocity suitable for injection into a drift tube linac

  15. Dynamics of Information Systems

    CERN Document Server

    Hirsch, Michael J; Murphey, Robert

    2010-01-01

    Our understanding of information and information dynamics has outgrown classical information theory. This book presents the research explaining the importance of information in the evolution of a distributed or networked system. It presents techniques for measuring the value or significance of information within the context of a system

  16. Studies in Chemical Dynamics

    International Nuclear Information System (INIS)

    Rabitz, Herschel; Ho, Tak-San

    2003-01-01

    This final report draws together the research carried from February, 1986 through January, 2003 concerning a series of topics in chemical dynamics. The specific areas of study include molecular collisions, chemical kinetics, data inversion to extract potential energy surfaces, and model reduction of complex kinetic systems

  17. Pathwise dynamic programming

    NARCIS (Netherlands)

    Bender, Christian; Gärtner, Christian; Schweizer, Nikolaus

    2017-01-01

    We present a novel method for deriving tight Monte Carlo confidence intervals for solutions of stochastic dynamic programming equations. Taking some approximate solution to the equation as an input, we construct pathwise recursions with a known bias. Suitably coupling the recursions for lower and

  18. Structural dynamics in FBR

    International Nuclear Information System (INIS)

    Bhoje, S.B.

    2003-01-01

    In view of thin walled large diameter shell structures with associated fluid effects, structural dynamics problems are very critical in a fast breeder reactor. Structural characteristics and consequent structural dynamics problems in typical pool type Fast Breeder Reactor are highlighted. A few important structural dynamics problems are pump induced as well as flow induced vibrations, seismic excitations, pressure transients in the intermediate heat exchangers and pipings due to a large sodium water reaction in the steam generator, and core disruptive accident loadings. The vibration problems which call for identification of excitation forces, formulation of special governing equations and detailed analysis with fluid structure interaction and sloshing effects, particularly for the components such as PSP, inner vessel, CP, CSRDM and TB are elaborated. Seismic design issues are presented in a comprehensive way. Other transient loadings which are specific to FBR, resulting from sodium-water reaction and core disruptive accident are highlighted. A few important results of theoretical as well as experimental works carried out for 500 MWe Prototype Fast Breeder Reactor (PFBR), in the domain of structural dynamics are presented. (author)

  19. Some Dynamics of Authorship.

    Science.gov (United States)

    Dunkin, Mick

    1992-01-01

    A study of the relationship between faculty publishing and career advancement at the University of Sydney (Australia) controlled for both gender and discipline. Results revealed some previously unseen dynamics of authorship, bringing into question common assumptions about solo vs. multiple authors and order of author names. Some discipline-related…

  20. Functional System Dynamics

    NARCIS (Netherlands)

    Ligterink, N.E.

    2007-01-01

    Functional system dynamics is the analysis, modelling, and simulation of continuous systems usually described by partial differential equations. From the infinite degrees of freedom of such systems only a finite number of relevant variables have to be chosen for a practical model description. The

  1. Dynamics of homogeneous nucleation

    DEFF Research Database (Denmark)

    Toxværd, Søren

    2015-01-01

    The classical nucleation theory for homogeneous nucleation is formulated as a theory for a density fluctuation in a supersaturated gas at a given temperature. But molecular dynamics simulations reveal that it is small cold clusters which initiates the nucleation. The temperature in the nucleating...

  2. ESSENTIAL DYNAMICS OF PROTEINS

    NARCIS (Netherlands)

    AMADEI, A; LINSSEN, ABM; BERENDSEN, HJC

    1993-01-01

    Analysis of extended molecular dynamics (MD) simulations of lysozyme in vacuo and in aqueous solution reveals that it is possible to separate the configurational space into two subspaces: (1) an ''essential'' subspace containing only a few degrees of freedom in which anharmonic motion occurs that

  3. Antiparallel Dynamic Covalent Chemistries

    NARCIS (Netherlands)

    Matysiak, Bartosz M.; Nowak, Piotr; Cvrtila, Ivica; Pappas, Charalampos G.; Liu, Bin; Komaromy, David; Otto, Sijbren

    2017-01-01

    The ability to design reaction networks with high, but addressable complexity is a necessary prerequisite to make advanced functional chemical systems. Dynamic combinatorial chemistry has, proven to be a useful tool in achieving complexity, however with some limitations in controlling it. Herein we

  4. Dynamics of human movement

    NARCIS (Netherlands)

    Koopman, Hubertus F.J.M.

    2010-01-01

    The part of (bio)mechanics that studies the interaction of forces on the human skeletal system and its effect on the resulting movement is called rigid body dynamics. Some basic concepts are presented: A mathematical formulation to describe human movement and how this relates on the mechanical loads

  5. Dynamic quantum secret sharing

    International Nuclear Information System (INIS)

    Jia, Heng-Yue; Wen, Qiao-Yan; Gao, Fei; Qin, Su-Juan; Guo, Fen-Zhuo

    2012-01-01

    In this Letter we consider quantum secret sharing (QSS) between a sender and a dynamic agent group, called dynamic quantum secret sharing (DQSS). In the DQSS, the change of the agent group is allowable during the procedure of sharing classical and quantum information. Two DQSS schemes are proposed based on a special kind of entangled state, starlike cluster states. Without redistributing all the shares, the changed agent group can reconstruct the sender's secret by their cooperation. Compared with the previous quantum secret sharing scheme, our schemes are more flexible and suitable for practical applications. -- Highlights: ► We consider quantum secret sharing between a sender and a dynamic agent group, called dynamic quantum secret sharing (DQSS). ► In the DQSS, the change of the agent group is allowable during the procedure of sharing classical and quantum information. ► Two DQSS schemes are proposed based on a special kind of entangled state, starlike cluster states. ► Without redistributing all the shares, the changed agent group can reconstruct the sender's secret by their cooperation. ► Compared with the previous quantum secret sharing scheme, our schemes are more flexible and suitable for practical applications.

  6. Overeducation Dynamics and Personality

    Science.gov (United States)

    Blazquez, Maite; Budria, Santiago

    2012-01-01

    In this paper, we use the 2000-2008 waves of the German Socioeconomic Panel to examine overeducation transitions. The results are based on a first-order Markov model that allows us to account for both the initial conditions problem and potential endogeneity in attrition. We found that overeducation dynamics, especially the probability of entering…

  7. Dynamic accelerator modeling

    International Nuclear Information System (INIS)

    Nishimura, Hiroshi.

    1993-05-01

    Object-Oriented Programming has been used extensively to model the LBL Advanced Light Source 1.5 GeV electron storage ring. This paper is on the present status of the class library construction with emphasis on a dynamic modeling

  8. Dynamic Optically Multiplexed Imaging

    Science.gov (United States)

    2015-07-29

    Dynamic Optically Multiplexed Imaging Yaron Rachlin, Vinay Shah, R. Hamilton Shepard, and Tina Shih Lincoln Laboratory, Massachusetts Institute of...V. Shah, and T. Shih “Design Architectures for Optically Multiplexed Imaging,” in submission 9 R. Gupta , P. Indyk, E. Price, and Y. Rachlin

  9. Quantum dynamical entropy revisited

    International Nuclear Information System (INIS)

    Hudetz, T.

    1996-10-01

    We define a new quantum dynamical entropy, which is a 'hybrid' of the closely related, physically oriented entropy introduced by Alicki and Fannes in 1994, and of the mathematically well-developed, single-argument entropy introduced by Connes, Narnhofer and Thirring in 1987. We show that this new quantum dynamical entropy has many properties similar to the ones of the Alicki-Fannes entropy, and also inherits some additional properties from the CNT entropy. In particular, the 'hybrid' entropy interpolates between the two different ways in which both the AF and the CNT entropy of the shift automorphism on the quantum spin chain agree with the usual quantum entropy density, resulting in even better agreement. Also, the new quantum dynamical entropy generalizes the classical dynamical entropy of Kolmogorov and Sinai in the same way as does the AF entropy. Finally, we estimate the 'hybrid' entropy both for the Powers-Price shift systems and for the noncommutative Arnold map on the irrational rotation C * -algebra, leaving some interesting open problems. (author)

  10. Dynamic Contingency Analysis Tool

    Energy Technology Data Exchange (ETDEWEB)

    2016-01-14

    The Dynamic Contingency Analysis Tool (DCAT) is an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power system planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. Outputs from the DCAT will help find mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. The current prototype DCAT implementation has been developed as a Python code that accesses the simulation functions of the Siemens PSS/E planning tool (PSS/E). It has the following features: It uses a hybrid dynamic and steady-state approach to simulating the cascading outage sequences that includes fast dynamic and slower steady-state events. It integrates dynamic models with protection scheme models for generation, transmission, and load. It models special protection systems (SPSs)/remedial action schemes (RASs) and automatic and manual corrective actions. Overall, the DCAT attempts to bridge multiple gaps in cascading-outage analysis in a single, unique prototype tool capable of automatically simulating and analyzing cascading sequences in real systems using multiprocessor computers.While the DCAT has been implemented using PSS/E in Phase I of the study, other commercial software packages with similar capabilities can be used within the DCAT framework.

  11. Dynamics via measurability

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Generators f for σ -algebras can be used to view the dynamics of an invertible measurable transformation T in terms of the range values of f ∘ T . Such generators are the norm rather than the exception. Related measurable and quantitative methods of estimating a function from the behavior of ergodic averages are also discussed.

  12. Molecular dynamics for fermions

    International Nuclear Information System (INIS)

    Feldmeier, H.; Schnack, J.

    2000-02-01

    The time-dependent variational principle for many-body trial states is used to discuss the relation between the approaches of different molecular dynamics models to describe indistinguishable fermions. Early attempts to include effects of the Pauli principle by means of nonlocal potentials as well as more recent models which work with antisymmetrized many-body states are reviewed under these premises. (orig.)

  13. Dynamic term structure models

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Meldrum, Andrew

    This paper studies whether dynamic term structure models for US nominal bond yields should enforce the zero lower bound by a quadratic policy rate or a shadow rate specification. We address the question by estimating quadratic term structure models (QTSMs) and shadow rate models with at most four...

  14. Innovations in dynamic architecture

    Directory of Open Access Journals (Sweden)

    Abdulmajid Karanouh

    2015-11-01

    Full Text Available High performance adaptive solutions are capable of responding to the dynamic nature of users and context. These innovative and dynamic systems are steadily gaining ground over ubiquitous ‘best fit’ static models. These architectural elements often exist beyond the scope of mainstream building standards and traditional methods for data representation or communication. This presents major challenges to a highly standardized and compartmentalized industry in which ‘innovation’ is limited to a few signature practices that design iconic yet expensive structures, which often prioritize aesthetics over performance. This paper offers an overview of the benefits that integrated dynamic systems bring to buildings. Through an examination of an applied practice, this paper offers guidelines for communicating complex geometry in a clear design language across interdisciplinary collaborations. The use of diagrammatic grammar to translate underlying algorithmic rules into instructions for design allows complex, innovative solutions to be realized more effectively. The ideas presented here are based on the design principles of the competition-winning scheme of the Al-Bahr Towers. As lead consultant in Innovation Design & Research at AHR (former Aedas-UK, Abdulmajid Karanouh designed and spearheaded this project in close collaboration with Arup. The buildings won the Best Innovation Award 2012 by the Council for Tall Buildings and Urban Habitat (CTBUH. The pair of towers won recognition for its performance-driven form, and dynamic facade that operates following the movement of the sun.

  15. The Dynamics of Information

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    efficacy at making predictions in the real world. About the speaker Bernardo Huberman is a Senior HP Fellow and Director of the Information Dynamics Lab at Hewlett Packard Laboratories. He received his Ph.D. in Physics from the University of Pennsylvania, and is currently a Consulting Professor in the Department of Applied Physics at Stanford University...

  16. Dynamical clockwork axions

    Science.gov (United States)

    Coy, Rupert; Frigerio, Michele; Ibe, Masahiro

    2017-10-01

    The clockwork mechanism is a novel method for generating a large separation between the dynamical scale and interaction scale of a theory. We demonstrate how the mechanism can arise from a sequence of strongly-coupled sectors. This framework avoids elementary scalar fields as well as ad hoc continuous global symmetries, both of which are subject to serious stability issues. The clockwork factor, q, is determined by the consistency of the strong dynamics. The preserved global U(1) of the clockwork appears as an accidental symmetry, resulting from discrete or U(1) gauge symmetries, and it is spontaneously broken by the chiral condensates. We apply such a dynamical clockwork to construct models with an effectively invisible QCD axion from TeV-scale strong dynamics. The axion couplings are determined by the localisation of the Standard Model interactions along the clockwork sequence. The TeV spectrum includes either coloured hadrons or vector-like quarks. Dark matter can be accounted for by the axion or the lightest neutral baryons, which are accidentally stable.

  17. INDIANA: Beam dynamics experiments

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Beam dynamics experiments at the Indiana University Cooler Facility (IUCF) are helping to trace complicated non-linear effects in proton machines and could go on to pay important dividends in the detailed design of big new high energy proton storage rings

  18. Dynamics of Situation Definition

    Science.gov (United States)

    Park, Dongseop; Moro, Yuji

    2006-01-01

    Situation definition is the process and product of actors' interpretive activities toward a given situation. By reviewing a number of psychological studies conducted in experimental settings, we found that the studies have only explicated a part of the situation definition process and have neglected its dynamic aspects. We need to focus on the…

  19. Beam dynamics group summary

    International Nuclear Information System (INIS)

    Peggs, S.

    1994-01-01

    This paper summarizes the activities of the beam dynamics working group of the LHC Collective Effects Workshop that was held in Montreux in 1994. It reviews the presentations that were made to the group, the discussions that ensued, and the consensuses that evolved

  20. Functional System Dynamics

    OpenAIRE

    Ligterink, N.E.

    2007-01-01

    Functional system dynamics is the analysis, modelling, and simulation of continuous systems usually described by partial differential equations. From the infinite degrees of freedom of such systems only a finite number of relevant variables have to be chosen for a practical model description. The proper input and output of the system are an important part of the relevant variables.

  1. From symmetries to dynamics

    International Nuclear Information System (INIS)

    Stern, J.

    2000-01-01

    The problem of a uniform description of symmetries, their dynamic disturbing and the structure of the vacuum is discussed. The role which problems of this kind played in searching for and understanding the Standard Model of elementary particles from the 1960s till now is also highlighted. (Z.J.)

  2. Dynamic panel data models

    NARCIS (Netherlands)

    Bun, M.J.G.; Sarafidis, V.

    2013-01-01

    This Chapter reviews the recent literature on dynamic panel data models with a short time span and a large cross-section. Throughout the discussion we considerlinear models with additional endogenous covariates. First we give a broad overview of available inference methods placing emphasis on GMM.

  3. Unemployment Dynamics and Age

    NARCIS (Netherlands)

    Berg, van den G.J.; Gijsbert, A.; Lomwel, van C.; Ours, van Jan C.

    1998-01-01

    Youth unemployment is an issue of primary concern in WesternEuropean countries. In this paper we analyze dynamics in unemployment foryouths, adults (prime-aged individuals), and elderly. We use quarterly Frenchunemployment data, stratified by gender, age group, and duration, over theperiod

  4. The dynamics of awareness

    NARCIS (Netherlands)

    van Benthem, J.; Velázquez-Quesada, F.R.

    2010-01-01

    Classical epistemic logic describes implicit knowledge of agents about facts and knowledge of other agents based on semantic information. The latter is produced by acts of observation or communication that are described well by dynamic epistemic logics. What these logics do not describe, however, is

  5. Reactor dynamics calculations

    International Nuclear Information System (INIS)

    Devooght, J.; Lefvert, T.; Stankiewiez, J.

    1981-01-01

    This chapter deals with the work done in reactor dynamics within the Coordinated Research Program on Transport Theory and Advanced Reactor Calculations by three groups in Belgium, Poland, Sweden and Italy. Discretization methods in diffusion theory, collision probability methods in time-dependent neutron transport and singular perturbation method are represented in this paper

  6. Dynamics of chaotic strings

    International Nuclear Information System (INIS)

    Schaefer, Mirko

    2011-01-01

    The main topic of this thesis is the investigation of dynamical properties of coupled Tchebycheff map networks. The results give insights into the chaotic string model and its network generalization from a dynamical point of view. As a first approach, discrete symmetry transformations of the model are studied. These transformations are formulated in a general way in order to be also applicable to similar dynamics on bipartite network structures. The dynamics is studied numerically via Lyapunov measures, spatial correlations, and ergodic properties. It is shown that the zeros of the interaction energy are distinguished only with respect to this specific observable, but not by a more general dynamical principle. The original chaotic string model is defined on a one-dimensional lattice (ring-network) as the underlying network topology. This thesis studies a modification of the model based on the introduction of tunable disorder. The effects of inhomogeneous coupling weights as well as small-world perturbations of the ring-network structure on the interaction energy are discussed. Synchronization properties of the chaotic string model and its network generalization are studied in later chapters of this thesis. The analysis is based on the master stability formalism, which relates the stability of the synchronized state to the spectral properties of the network. Apart from complete synchronization, where the dynamics at all nodes of the network coincide, also two-cluster synchronization on bipartite networks is studied. For both types of synchronization it is shown that depending on the type of coupling the synchronized dynamics can display chaotic as well as periodic or quasi-periodic behaviour. The semi-analytical calculations reveal that the respective synchronized states are often stable for a wide range of coupling values even for the ring-network, although the respective basins of attraction may inhabit only a small fraction of the phase space. To provide

  7. Dynamic Topography Revisited

    Science.gov (United States)

    Moresi, Louis

    2015-04-01

    Dynamic Topography Revisited Dynamic topography is usually considered to be one of the trinity of contributing causes to the Earth's non-hydrostatic topography along with the long-term elastic strength of the lithosphere and isostatic responses to density anomalies within the lithosphere. Dynamic topography, thought of this way, is what is left over when other sources of support have been eliminated. An alternate and explicit definition of dynamic topography is that deflection of the surface which is attributable to creeping viscous flow. The problem with the first definition of dynamic topography is 1) that the lithosphere is almost certainly a visco-elastic / brittle layer with no absolute boundary between flowing and static regions, and 2) the lithosphere is, a thermal / compositional boundary layer in which some buoyancy is attributable to immutable, intrinsic density variations and some is due to thermal anomalies which are coupled to the flow. In each case, it is difficult to draw a sharp line between each contribution to the overall topography. The second definition of dynamic topography does seem cleaner / more precise but it suffers from the problem that it is not measurable in practice. On the other hand, this approach has resulted in a rich literature concerning the analysis of large scale geoid and topography and the relation to buoyancy and mechanical properties of the Earth [e.g. refs 1,2,3] In convection models with viscous, elastic, brittle rheology and compositional buoyancy, however, it is possible to examine how the surface topography (and geoid) are supported and how different ways of interpreting the "observable" fields introduce different biases. This is what we will do. References (a.k.a. homework) [1] Hager, B. H., R. W. Clayton, M. A. Richards, R. P. Comer, and A. M. Dziewonski (1985), Lower mantle heterogeneity, dynamic topography and the geoid, Nature, 313(6003), 541-545, doi:10.1038/313541a0. [2] Parsons, B., and S. Daly (1983), The

  8. Complexity in Dynamical Systems

    Science.gov (United States)

    Moore, Cristopher David

    The study of chaos has shown us that deterministic systems can have a kind of unpredictability, based on a limited knowledge of their initial conditions; after a finite time, the motion appears essentially random. This observation has inspired a general interest in the subject of unpredictability, and more generally, complexity; how can we characterize how "complex" a dynamical system is?. In this thesis, we attempt to answer this question with a paradigm of complexity that comes from computer science, we extract sets of symbol sequences, or languages, from a dynamical system using standard methods of symbolic dynamics; we then ask what kinds of grammars or automata are needed a generate these languages. This places them in the Chomsky heirarchy, which in turn tells us something about how subtle and complex the dynamical system's behavior is. This gives us insight into the question of unpredictability, since these automata can also be thought of as computers attempting to predict the system. In the culmination of the thesis, we find a class of smooth, two-dimensional maps which are equivalent to the highest class in the Chomsky heirarchy, the turning machine; they are capable of universal computation. Therefore, these systems possess a kind of unpredictability qualitatively different from the usual "chaos": even if the initial conditions are known exactly, questions about the system's long-term dynamics are undecidable. No algorithm exists to answer them. Although this kind of unpredictability has been discussed in the context of distributed, many-degree-of -freedom systems (for instance, cellular automata) we believe this is the first example of such phenomena in a smooth, finite-degree-of-freedom system.

  9. Dynamic stiffness of suction caissons

    DEFF Research Database (Denmark)

    Ibsen, Lars Bo; Liingaard, Morten; Andersen, Lars

    The purpose of this report is to evaluate the dynamic soil-structure interaction of suction caissons for offshore wind turbines. The investigation is limited to a determination of the vertical dynamic stiffness of suction caissons. The soil surrounding the foundation is homogenous with linear...... viscoelastic properties. The dynamic stiffness of the suction caisson is expressed by dimensionless frequency-dependent dynamic stiffness coefficients corresponding to the vertical degree of freedom. The dynamic stiffness coefficients for the foundations are evaluated by means of a dynamic three...

  10. NVU dynamics. II. Comparing to four other dynamics

    DEFF Research Database (Denmark)

    Ingebrigtsen, Trond; Toxværd, Søren; Schrøder, Thomas

    2011-01-01

    -potential-energy hypersurface. Here, simulations of NVU dynamics are compared to results for four other dynamics, both deterministic and stochastic. First, NVU dynamics is compared to the standard energy-conserving Newtonian NVE dynamics by simulations of the Kob-Andersen binary Lennard-Jones liquid, its WCA version (i.......e., with cut-off's at the pair potential minima), and the Lennard-Jones Gaussian liquid. We find identical results for all quantities probed: radial distribution functions, incoherent intermediate scattering functions, and mean-square displacement as function of time. Arguments are presented...... on the constant-potential-energy hypersurface, and to Nos-Hoover NVT dynamics. If time is scaled for the two stochastic dynamics to make single-particle diffusion constants identical to that of NVE dynamics, the simulations show that all five dynamics are equivalent at low temperatures except at short times....

  11. Truly random dynamics generated by autonomous dynamical systems

    Science.gov (United States)

    González, J. A.; Reyes, L. I.

    2001-09-01

    We investigate explicit functions that can produce truly random numbers. We use the analytical properties of the explicit functions to show that a certain class of autonomous dynamical systems can generate random dynamics. This dynamics presents fundamental differences with the known chaotic systems. We present real physical systems that can produce this kind of random time-series. Some applications are discussed.

  12. Double Dynamic Supramolecular Polymers of Covalent Oligo-Dynamers

    NARCIS (Netherlands)

    Schaeffer, Gaël; Buhler, Eric; Candau, Sauveur Jean; Lehn, Jean-Marie

    2013-01-01

    Double-dynamic polymers, incorporating both molecular and supramolecular dynamic features (“double dynamers”) have been generated, where these functions are present in a nonstoichiometric ratio in the main chain of the polymer. It has been achieved by (1) the formation of covalent oligo-dynamers in

  13. GIS and dynamic phenomena modeling

    Czech Academy of Sciences Publication Activity Database

    Klimešová, Dana

    2006-01-01

    Roč. 4, č. 4 (2006), s. 11-15 ISSN 0139-570X Institutional research plan: CEZ:AV0Z10750506 Keywords : dynamic modelling * temporal analysis * dynamics evaluation * temporal space Subject RIV: BC - Control Systems Theory

  14. Dynamic Approaches for Multichoice Solutions

    Directory of Open Access Journals (Sweden)

    Yu-Hsien Liao

    2011-01-01

    Full Text Available Based on alternative reduced games, several dynamic approaches are proposed to show how the three extended Shapley values can be reached dynamically from arbitrary efficient payoff vectors on multichoice games.

  15. Dynamic Flaps Electronic Scan Antenna

    National Research Council Canada - National Science Library

    Gonzalez, Daniel

    2000-01-01

    A dynamic FLAPS(TM) electronic scan antenna was the focus of this research. The novelty S of this SBIR resides in the use of plasma as the main component of this dynamic X-Band phased S array antenna...

  16. Dynamics of poroelastic foams

    Science.gov (United States)

    Forterre, Yoel; Sobac, Benjamin

    2010-11-01

    Soft poroelastic structures are widespread in biological tissues such as cartilaginous joints in bones, blood-filled placentae or plant organs. Here we investigate the dynamics of open elastic foams immersed in viscous fluids, as model soft poroelastic materials. The experiment consists in slowly compacting blocs of polyurethane solid foam embedded in silicon oil-tanks and studying their relaxation to equilibrium when the confining stress is suddenly released. Measurements of the local fluid pressure and foam velocity field are compared with a simple two-phase flow approach. For small initial compactions, the results show quantitative agreement with the classical diffusion theory of soil consolidation (Terzaghi, Biot). On the other hand, for large initial compactions, the dynamics exhibits long relaxation times and decompaction fronts, which are mainly controlled by the highly non-linear mechanical response of the foam. The analogy between this process and the evaporation of a polymer melt close to the glass transition will be briefly discussed.

  17. Contact Line Dynamics

    Science.gov (United States)

    Kreiss, Gunilla; Holmgren, Hanna; Kronbichler, Martin; Ge, Anthony; Brant, Luca

    2017-11-01

    The conventional no-slip boundary condition leads to a non-integrable stress singularity at a moving contact line. This makes numerical simulations of two-phase flow challenging, especially when capillarity of the contact point is essential for the dynamics of the flow. We will describe a modeling methodology, which is suitable for numerical simulations, and present results from numerical computations. The methodology is based on combining a relation between the apparent contact angle and the contact line velocity, with the similarity solution for Stokes flow at a planar interface. The relation between angle and velocity can be determined by theoretical arguments, or from simulations using a more detailed model. In our approach we have used results from phase field simulations in a small domain, but using a molecular dynamics model should also be possible. In both cases more physics is included and the stress singularity is removed.

  18. Dynamics and Relativity

    CERN Document Server

    Forshaw, Jeffrey

    2009-01-01

    A new title in the Manchester Physics Series, this introductory text emphasises physical principles behind classical mechanics and relativity. It assumes little in the way of prior knowledge, introducing relevant mathematics and carefully developing it within a physics context. Designed to provide a logical development of the subject, the book is divided into four sections, introductory material on dynamics, and special relativity, which is then followed by more advanced coverage of dynamics and special relativity. Each chapter includes problems ranging in difficulty from simple to challenging with?solutions for solving problems. Includes?solutions for solving problemsNumerous worked examples included throughout the bookMathematics is carefully explained and developed within a physics environmentSensitive to topics that can appear daunting or confusing

  19. Fluid dynamics an introduction

    CERN Document Server

    Rieutord, Michel

    2015-01-01

    This book is dedicated to readers who want to learn fluid dynamics from the beginning. It assumes a basic level of mathematics knowledge that would correspond to that of most second-year undergraduate physics students and examines fluid dynamics from a physicist’s perspective. As such, the examples used primarily come from our environment on Earth and, where possible, from astrophysics. The text is arranged in a progressive and educational format, aimed at leading readers from the simplest basics to more complex matters like turbulence and magnetohydrodynamics. Exercises at the end of each chapter help readers to test their understanding of the subject (solutions are provided at the end of the book), and a special chapter is devoted to introducing selected aspects of mathematics that beginners may not be familiar with, so as to make the book self-contained.

  20. Nonautonomous dynamical systems

    CERN Document Server

    Kloeden, Peter E

    2011-01-01

    The theory of nonautonomous dynamical systems in both of its formulations as processes and skew product flows is developed systematically in this book. The focus is on dissipative systems and nonautonomous attractors, in particular the recently introduced concept of pullback attractors. Linearization theory, invariant manifolds, Lyapunov functions, Morse decompositions and bifurcations for nonautonomous systems and set-valued generalizations are also considered as well as applications to numerical approximations, switching systems and synchronization. Parallels with corresponding theories of control and random dynamical systems are briefly sketched. With its clear and systematic exposition, many examples and exercises, as well as its interesting applications, this book can serve as a text at the beginning graduate level. It is also useful for those who wish to begin their own independent research in this rapidly developing area.

  1. Optimization by record dynamics

    DEFF Research Database (Denmark)

    Barettin, Daniele; Sibani, Paolo

    2014-01-01

    Large dynamical changes in thermalizing glassy systems are triggered by trajectories crossing record sized barriers, a behavior revealing the presence of a hierarchical structure in configuration space. The observation is here turned into a novel local search optimization algorithm dubbed record...... dynamics optimization,or RDO. RDO uses the Metropolis rule to accept or reject candidate solutions depending on the value of a parameter akin to the temperature and minimizes the cost function of the problem at hand through cycles where its ‘temperature’ is raised and subsequently decreased in order......), is applied to the same problem as a benchmark. RDO and PT turn out to produce solutions of similar quality for similar numerical effort, but RDO is simpler to program and additionally yields geometrical information on the system’s configuration space which is of interest in many applications. In particular...

  2. Fusion-fission dynamics

    International Nuclear Information System (INIS)

    Blocki, J.; Planeta, R.; Brzychczyk, J.; Grotowski, K.

    1991-04-01

    Classical dynamical calculations of the heavy ion induced fission process for the reactions 40 Ar+ 141 Pr, 20 Ne+ 165 Ho and 12 C+ 175 Lu leading to the iridium like nucleus have been performed. As a result prescission lifetimes were obtained and compared with the experimental values. The agreement between the calculated and experimental lifetimes indicates that the one-body dissipation picture is much more relevant in describing the fusion-fission dynamics than the two-body one. Somewhat bigger calculated times than the experimental ones in case of the C+Lu reaction at 16 MeV/nucleon may be a signal on the energy range applicability of the one-body dissipation model. (author)

  3. Corruption dynamics model

    Science.gov (United States)

    Malafeyev, O. A.; Nemnyugin, S. A.; Rylow, D.; Kolpak, E. P.; Awasthi, Achal

    2017-07-01

    The corruption dynamics is analyzed by means of the lattice model which is similar to the three-dimensional Ising model. Agents placed at nodes of the corrupt network periodically choose to perfom or not to perform the act of corruption at gain or loss while making decisions based on the process history. The gain value and its dynamics are defined by means of the Markov stochastic process modelling with parameters established in accordance with the influence of external and individual factors on the agent's gain. The model is formulated algorithmically and is studied by means of the computer simulation. Numerical results are obtained which demonstrate asymptotic behaviour of the corruption network under various conditions.

  4. Multiple time scale dynamics

    CERN Document Server

    Kuehn, Christian

    2015-01-01

    This book provides an introduction to dynamical systems with multiple time scales. The approach it takes is to provide an overview of key areas, particularly topics that are less available in the introductory form.  The broad range of topics included makes it accessible for students and researchers new to the field to gain a quick and thorough overview. The first of its kind, this book merges a wide variety of different mathematical techniques into a more unified framework. The book is highly illustrated with many examples and exercises and an extensive bibliography. The target audience of this  book are senior undergraduates, graduate students as well as researchers interested in using the multiple time scale dynamics theory in nonlinear science, either from a theoretical or a mathematical modeling perspective. 

  5. Microscopic dynamical Casimir effect

    Science.gov (United States)

    Souza, Reinaldo de Melo e.; Impens, François; Neto, Paulo A. Maia

    2018-03-01

    We consider an atom in its ground state undergoing a nonrelativistic oscillation in free space. The interaction with the electromagnetic quantum vacuum leads to two effects to leading order in perturbation theory. When the mechanical frequency is larger than the atomic transition frequency, the dominant effect is the motion-induced transition to an excited state with the emission of a photon carrying the excess energy. We compute the angular distribution of emitted photons and the excitation rate. On the other hand, when the mechanical frequency is smaller than the transition frequency, the leading-order effect is the parametric emission of photon pairs, which constitutes the microscopic counterpart of the dynamical Casimir effect. We discuss the properties of the microscopic dynamical Casimir effect and build a connection with the photon production by an oscillating macroscopic metallic mirror.

  6. Dynamic nuclear spin polarization

    Energy Technology Data Exchange (ETDEWEB)

    Stuhrmann, H B [GKSS-Forschungszentrum Geesthacht GmbH (Germany)

    1996-11-01

    Polarized neutron scattering from dynamic polarized targets has been applied to various hydrogenous materials at different laboratories. In situ structures of macromolecular components have been determined by nuclear spin contrast variation with an unprecedented precision. The experiments of selective nuclear spin depolarisation not only opened a new dimension to structural studies but also revealed phenomena related to propagation of nuclear spin polarization and the interplay of nuclear polarisation with the electronic spin system. The observation of electron spin label dependent nuclear spin polarisation domains by NMR and polarized neutron scattering opens a way to generalize the method of nuclear spin contrast variation and most importantly it avoids precontrasting by specific deuteration. It also likely might tell us more about the mechanism of dynamic nuclear spin polarisation. (author) 4 figs., refs.

  7. Dynamics of star clusters

    International Nuclear Information System (INIS)

    Goodman, J.; Hut, P.

    1985-01-01

    The enigma of core collapse receives much attention in this volume. In addition, several observational papers summarize recent techniques and results and discuss the stellar dynamical implications of the enormous progress in the quality of surface photometry, proper motion studies, radial velocity determinations, as well as space-based measurements in a variety of wavelengths. The value of these Proceedings as a standard reference work is enhanced by the inclusion of two appendices, featuring English translations of two seminal papers on stellar dynamics published in Russian and not previously available in a Western language. A third appendix contains an up-to-date catalogue of observationally determined parameters of galactic globular clusters, as well as theoretically inferred parameters. This catalogue will prove to be an essential reference for phenomenonological studies and an ideal testing ground for new theoretical developments. (orig.)

  8. Dynamic international oil markets

    International Nuclear Information System (INIS)

    van der Linde, C.

    1992-01-01

    Dynamic International Oil Market Developments and Structure 1860-1990 discusses the logic of changing market structures of the international oil industry. The market structures have, in the course of time, oscillated between competition and oligopoly, as the oil market expanded, matured, stagnated, and expanded again. This book provides a dynamic interpretation of the intensifying struggle among producer, and consumer governments, and oil companies, over the distribution of economic rents and profits. In particular, it shows the shifting fortunes of the governments and companies as they try to control the recurring capacity constraints between the upstream and downstream sectors, generated by the instability of the oil market. The first part of the book examines market conditions and developments between 1860 and 1990; the second part analyzes market structures after 1945

  9. Dynamic Data Structures

    DEFF Research Database (Denmark)

    Kejlberg-Rasmussen, Casper

    statements about our data structure, which are based on the structure of the underlying problem, that we are trying to solve. We can rely on the properties of the invariants when performing queries, and in return we need to ensure that the invariants remain true after we perform updates. When designing data......In this thesis I will address three dynamic data structure problems using the concept of invariants. The first problem is maintaining a dynamically changing set of keys – a dictionary – where the queries we can ask are: does it contain a given key? and what is the preceding (or succeeding) key...... to a given key? The updates we can do are: inserting a new key or deleting a given key. Our dictionary has the working set property, which means that the running time of a query depends on the query distribution. Specifically the time to search for a key depends on when we last searched for it. Our data...

  10. Dynamic coherent backscattering mirror

    Energy Technology Data Exchange (ETDEWEB)

    Zeylikovich, I.; Xu, M., E-mail: mxu@fairfield.edu [Physics Department, Fairfield University, Fairfield, CT 06824 (United States)

    2016-02-15

    The phase of multiply scattered light has recently attracted considerable interest. Coherent backscattering is a striking phenomenon of multiple scattered light in which the coherence of light survives multiple scattering in a random medium and is observable in the direction space as an enhancement of the intensity of backscattered light within a cone around the retroreflection direction. Reciprocity also leads to enhancement of backscattering light in the spatial space. The random medium behaves as a reciprocity mirror which robustly converts a diverging incident beam into a converging backscattering one focusing at a conjugate spot in space. Here we first analyze theoretically this coherent backscattering mirror (CBM) phenomenon and then demonstrate the capability of CBM compensating and correcting both static and dynamic phase distortions occurring along the optical path. CBM may offer novel approaches for high speed dynamic phase corrections in optical systems and find applications in sensing and navigation.

  11. Dislocation-dynamics method

    International Nuclear Information System (INIS)

    Van Brutzel, L.

    2015-01-01

    Dislocation-Dynamics (DD) technique is identified as the method able to model the evolution of material plastic properties as a function of the microstructural transformation predicted at the atomic scale. Indeed, it is the only simulation method capable of taking into account the collective behaviour of a large number of dislocations inside a realistic microstructure. DD simulations are based on the elastic dislocation theory following rules inherent to the dislocation core structure often call 'local rules'. All the data necessary to establish the local rules for DD have to come directly from experiment or alternatively from simulations carried out at the atomic scale such as molecular dynamics or ab initio calculations. However, no precise information on the interaction between two dislocations or between dislocations and defects induced by irradiation are available for nuclear fuels. Therefore, in this article the DD technique will be presented and some examples are given of what can be achieved with it. (author)

  12. Ultrafast magnetization dynamics

    OpenAIRE

    Woodford, Simon

    2008-01-01

    This thesis addresses ultrafast magnetization dynamics from a theoretical perspective. The manipulation of magnetization using the inverse Faraday effect has been studied, as well as magnetic relaxation processes in quantum dots. The inverse Faraday effect – the generation of a magnetic field by nonresonant, circularly polarized light – offers the possibility to control and reverse magnetization on a timescale of a few hundred femtoseconds. This is important both for the technological advant...

  13. Dynamics of Markets

    Science.gov (United States)

    McCauley, Joseph L.

    2004-06-01

    Standard texts and research in economics and finance ignore the absence of evidence from the analysis of real, unmassaged market data to support the notion of Adam Smith's stabilizing Invisible Hand. In stark contrast, this text introduces a new empirically-based model of financial market dynamics that explains the volatility of prices options correctly and clarifies the instability of financial markets. The emphasis is on understanding how real markets behave, not how they hypothetically 'should' behave.

  14. The chaotic dynamical aperture

    International Nuclear Information System (INIS)

    Lee, S.Y.; Tepikian, S.

    1985-01-01

    Nonlinear magnetic forces become more important for particles in the modern large accelerators. These nonlinear elements are introduced either intentionally to control beam dynamics or by uncontrollable random errors. Equations of motion in the nonlinear Hamiltonian are usually non-integrable. Because of the nonlinear part of the Hamiltonian, the tune diagram of accelerators is a jungle. Nonlinear magnet multipoles are important in keeping the accelerator operation point in the safe quarter of the hostile jungle of resonant tunes. Indeed, all the modern accelerator design have taken advantages of nonlinear mechanics. On the other hand, the effect of the uncontrollable random multipoles should be evaluated carefully. A powerful method of studying the effect of these nonlinear multipoles is using a particle tracking calculation, where a group of test particles are tracing through these magnetic multipoles in the accelerator hundreds to millions of turns in order to test the dynamical aperture of the machine. These methods are extremely useful in the design of a large accelerator such as SSC, LEP, HERA and RHIC. These calculations unfortunately take tremendous amount of computing time. In this paper, we try to apply the existing method in the nonlinear dynamics to study the possible alternative solution. When the Hamiltonian motion becomes chaotic, the tune of the machine becomes undefined. The aperture related to the chaotic orbit can be identified as chaotic dynamical aperture. We review the method of determining chaotic orbit and apply the method to nonlinear problems in accelerator physics. We then discuss the scaling properties and effect of random sextupoles

  15. Micro dynamics in mediation

    OpenAIRE

    Boserup, Hans

    2014-01-01

    The author has identified a number of styles in mediation, which lead to different processes and different outcomes. Through discourse and conversation analysis he examines the micro dynamics in three of these, the postmodern styles: systemic, transformative and narrative mediation. The differences between the three mediation ideologies and practice is illustrated through role play scripts enacted in each style. Mediator and providers of mediation and trainers in mediation are encouraged to a...

  16. Gas dynamic laser device

    International Nuclear Information System (INIS)

    Born, G.

    1975-01-01

    The gas dynamic laser device is provided with an expansion chamber arranged between a heating chamber for the CO-gas and the resonance chamber. The expansion chamber is initially evacuated for producing a rarefaction wave. Between the heating chamber and the expansion chamber there are arranged rapid release means such as a valve or a diaphragm. Pressure recovering means are connected to the other side of the resonance chamber

  17. Dynamics of Markets

    Science.gov (United States)

    McCauley, Joseph L.

    2009-09-01

    Preface; 1. Econophysics: why and what; 2. Neo-classical economic theory; 3. Probability and stochastic processes; 4. Introduction to financial economics; 5. Introduction to portfolio selection theory; 6. Scaling, pair correlations, and conditional densities; 7. Statistical ensembles: deducing dynamics from time series; 8. Martingale option pricing; 9. FX market globalization: evolution of the dollar to worldwide reserve currency; 10. Macroeconomics and econometrics: regression models vs. empirically based modeling; 11. Complexity; Index.

  18. Quasistatic Dynamics with Intermittency

    International Nuclear Information System (INIS)

    Leppänen, Juho; Stenlund, Mikko

    2016-01-01

    We study an intermittent quasistatic dynamical system composed of nonuniformly hyperbolic Pomeau–Manneville maps with time-dependent parameters. We prove an ergodic theorem which shows almost sure convergence of time averages in a certain parameter range, and identify the unique physical family of measures. The theorem also shows convergence in probability in a larger parameter range. In the process, we establish other results that will be useful for further analysis of the statistical properties of the model.

  19. Iteration and accelerator dynamics

    International Nuclear Information System (INIS)

    Peggs, S.

    1987-10-01

    Four examples of iteration in accelerator dynamics are studied in this paper. The first three show how iterations of the simplest maps reproduce most of the significant nonlinear behavior in real accelerators. Each of these examples can be easily reproduced by the reader, at the minimal cost of writing only 20 or 40 lines of code. The fourth example outlines a general way to iteratively solve nonlinear difference equations, analytically or numerically

  20. Generalized chiral membrane dynamics

    International Nuclear Information System (INIS)

    Cordero, R.; Rojas, E.

    2003-01-01

    We develop the dynamics of the chiral superconducting membranes (with null current) in an alternative geometrical approach. Besides of this, we show the equivalence of the resulting description with the one known Dirac-Nambu-Goto (DNG) case. Integrability for chiral string model is obtained using a proposed light-cone gauge. In a similar way, domain walls are integrated by means of a simple Ansatz. (Author)