Structural properties of the tubular appendage spinae from marine bacterium Roseobacter sp. strain YSCB

PubMed Central

Bernadac, A.; Wu, L.-F.; Santini, C.-L.; Vidaud, C.; Sturgis, J. N.; Menguy, N.; Bergam, P.; Nicoletti, C.; Xiao, T.

2012-01-01

Spinae are tubular surface appendages broadly found in Gram-negative bacteria. Little is known about their architecture, function or origin. Here, we report structural characterization of the spinae from marine bacteria Roseobacter sp. YSCB. Electron cryo-tomography revealed that a single filament winds into a hollow flared base with progressive change to a cylinder. Proteinase K unwound the spinae into proteolysis-resistant filaments. Thermal treatment ripped the spinae into ribbons that were melted with prolonged heating. Circular dichroism spectroscopy revealed a dominant beta-structure of the spinae. Differential scanning calorimetry analyses showed three endothermic transformations at 50–85°C, 98°C and 123°C, respectively. The heating almost completely disintegrated the spinae, abolished the 98°C transition and destroyed the beta-structure. Infrared spectroscopy identified the amide I spectrum maximum at a position similar to that of amyloid fibrils. Therefore, the spinae distinguish from other bacterial appendages, e.g. flagella and stalks, in both the structure and mechanism of assembly. PMID:23230515

Genetics and Spina Bifida

MedlinePlus

... that some babies will have it even when women take the right amount every day. Who is at risk for having a baby with Spina Bilda? Any woman who is capable of becoming ... 65 million women of childbearing age in the United States. Although ...

Men's Health and Spina Bifida

MedlinePlus

SBA National Resource Center: 800-621-3141 Men’s Health Urologic and Sexual Function Why is bladder control important for sexual activity? Ninety to ninety-lve percent of people with Spina Bilda ( ...

Spina Bifida and Motherhood.

ERIC Educational Resources Information Center

Drakes, Olive

1984-01-01

Two women with spina bifida, a disability in which the spinal cord and nerves are damaged, gave birth to healthy babies. The article points out the need to provide young girls having this condition with information and counseling regarding sexual relationships, parenthood, and child rearing. (CL)

Spina Bifida

PubMed Central

Copp, Andrew J.; Adzick, N. Scott; Chitty, Lyn S.; Fletcher, Jack M.; Holmbeck, Grayson N.; Shaw, Gary M.

2016-01-01

Spina bifida is a birth defect in which the vertebral column is open (bifid), often with spinal cord involvement. Clinically most significant is myelomeningocele (MMC; open spina bifida) in which the spinal neural tube fails to close during embryonic development. The exposed neural tissue degenerates in utero, resulting in neurological deficit that varies with level of the lesion. Occurring in around 1 per 1000 births worldwide, MMC is one of the commonest congenital malformations, yet its causation is largely unknown. The genetic component of MMC is estimated at 60-70% but few genes have yet been identified, despite much information from mouse models. Non-genetic risk factors include reduced folate intake, maternal anticonvulsant therapy, diabetes mellitus and obesity. Primary prevention by peri-conceptional folic acid has been demonstrated in clinical trials, leading to food fortification programmes in many countries. Prenatal diagnosis is by ultrasound enabling termination of pregnancy. Individuals who survive to birth have their lesions closed surgically, with subsequent management of associated defects, including the Chiari II malformation, hydrocephalus, and urological and orthopaedic sequelae. Fetal surgical repair of MMC has been associated with improved early neurological outcome compared with postnatal operation. MMC affects quality of life during childhood, adolescence, and into adulthood, posing a challenge for individuals, families and society as a whole. PMID:27189655

Fetal Endoscopic Surgery for Spina Bifida

ClinicalTrials.gov

2017-10-16

Neural Tube Defects; Spina Bifida, Open; Myelomeningocele; Fetal Disease; Hydrocephalus; Chiari Malformation Type 2; Congenital Abnormality; Surgery; Maternal, Uterus or Pelvic Organs, Affecting Fetus

Milestone achievement in emerging adulthood in spina bifida: a longitudinal investigation of parental expectations

PubMed Central

Holbein, Christina E; Zebracki, Kathy; Bechtel, Colleen F; Papadakis, Jaclyn Lennon; Bruno, Elizabeth Franks; Holmbeck, Grayson N

2016-01-01

Aim To assess changes over time in parents' expectations of adult milestone achievement (college attendance, full-time job attainment, independent living, marriage, parenthood) for young people with spina bifida, to examine how expectancies relate to actual milestone achievement, and to compare milestone achievement in emerging adults with spina bifida with that of peers with typical development. Method Sixty-eight families of children with spina bifida (mean=8.34y, 37 male, 31 female) and 68 families of children with typical development (mean=8.49y, 37 male, 31 female) participated at Time 1. At all subsequent timepoints, parents of young people with spina bifida were asked to rate their expectations of emerging adulthood milestone achievement. At Time 7, when participants were 22 to 23 years old, milestone achievement was assessed. Results Parents of young people with spina bifida lowered their expectations over time for most milestones; parents of children with higher cognitive ability reported decreases of lower magnitude. Parent expectancies were optimistic and unrelated to actual milestone achievement. Emerging adults with spina bifida were less likely than individuals with typical development to achieve all milestones. Interpretation Optimistic parental expectations may be adaptive for children with spina bifida and their families, although it is important for families to set realistic goals. Healthcare providers serve a key role in helping families of young people with spina bifida prepare for emerging adulthood. PMID:27651215

Spina Bifida Data and Statistics

MedlinePlus

... who had public insurance only. [ Read article summary ] Quality of Life Researchers studied the physical and psychological health and ... group two years later, comparing the health-related quality of life of children and young people with spina bifida ...

Trajectories of autonomy development across the adolescent transition in children with spina bifida.

PubMed

Friedman, Deborah; Holmbeck, Grayson N; DeLucia, Christian; Jandasek, Barbara; Zebracki, Kathy

2009-02-01

The current study investigated individual growth in autonomy development across the adolescent transition, comparing the trajectories of children with and without spina bifida. Individual growth curve modeling procedures were utilized to describe the developmental course of autonomy across four waves of data collection, from ages 9 to 15, and to test whether illness status [spina bifida vs. matched comparison group (N = 68 for both groups at Time 1)] would significantly predict individual variability in autonomy development. Potential moderators [child gender, SES, and Peabody Picture Vocabulary Test (PPVT) score] of the association between illness status and autonomy development were also examined. Children with spina bifida demonstrated distinct developmental trajectories, though the nature of the group differences varied by type of autonomy development (emotional vs. behavioral), context (i.e. school vs. family), and reporter. Significant interactions with PPVT score and child gender were found. Overall, children with spina bifida show considerable developmental resiliency, but may lag behind their peers in specific areas of autonomy. Boys with spina bifida, and children with spina bifida who have lower than average levels of verbal intelligence, appear to be at greater risk for exhibiting delays in autonomy development.

Milestone achievement in emerging adulthood in spina bifida: a longitudinal investigation of parental expectations.

PubMed

Holbein, Christina E; Zebracki, Kathy; Bechtel, Colleen F; Lennon Papadakis, Jaclyn; Franks Bruno, Elizabeth; Holmbeck, Grayson N

2017-03-01

To assess changes over time in parents' expectations of adult milestone achievement (college attendance, full-time job attainment, independent living, marriage, parenthood) for young people with spina bifida, to examine how expectancies relate to actual milestone achievement, and to compare milestone achievement in emerging adults with spina bifida with that of peers with typical development. Sixty-eight families of children with spina bifida (mean age 8y 4mo, 37 males, 31 females) and 68 families of children with typical development (mean age 8y 6mo, 37 males, 31 females) participated at Time 1. At all subsequent timepoints, parents of young people with spina bifida were asked to rate their expectations of emerging adulthood milestone achievement. At Time 7, when participants were 22 to 23 years old, milestone achievement was assessed. Parents of young people with spina bifida lowered their expectations over time for most milestones; parents of children with higher cognitive ability reported decreases of lower magnitude. Parent expectancies were optimistic and unrelated to actual milestone achievement. Emerging adults with spina bifida were less likely than individuals with typical development to achieve all milestones. Optimistic parental expectations may be adaptive for children with spina bifida and their families, although it is important for families to set realistic goals. Healthcare providers serve a key role in helping families of young people with spina bifida prepare for emerging adulthood. © 2016 Mac Keith Press.

Psychological and Educational Studies with Spina Bifida Children. Final Report.

ERIC Educational Resources Information Center

Diller, Leonard; And Others

To measure school achievements in spina bifida children, to relate these measures to certain variables, to obtain information on educational problems, and to study facets of cognition and its changes with age, 77 spina bifida children and 53 amputees (all aged 5 to 15) were tested. Sixty non-disabled children were at times used for controls. The…

Spina Bifida: General Information. Fact Sheet Number 12 = La Espina Bifida: Informacion General. Fact Sheet Number 21.

ERIC Educational Resources Information Center

Interstate Research Associates, McLean, VA.

This fact sheet on spina bifida is offered in both English and Spanish. It provides definitions of the three types of spina bifida (spina bifida occulta, meningocele, and myelomeningocele). Incidence figures are given as are typical characteristics of children with spina bifida. Educational implications are briefly noted, including the need to…

Pregnancy outcome and complications in women with spina bifida.

PubMed

Arata, M; Grover, S; Dunne, K; Bryan, D

2000-09-01

To describe the antenatal complications, mode of delivery and outcome of pregnancy in women with spina bifida. Case series of women known to have attended the spina bifida clinic at the Royal Children's Hospital. Medical records, postal questionnaire and telephone interview were utilized to collect data on the effect of pregnancy on the health of women and the effect of spina bifida on pregnancy outcome. Of 207 women born between 1945 and 1975, 23 reported having a pregnancy, and 17 who had completed pregnancies agreed to participate. The 17 women had a total of 29 pregnancies, with 23 pregnancies progressing to births. Fourteen of 17 women had antenatal admissions, with wheelchair-dependent women requiring more-frequent and longer admissions. Recurrent urinary infections in pregnancy occurred in women with a prior history of urinary infections; stomal problems occurred but were not serious; mobility was reduced for two women during pregnancy, with full recovery afterwards; and preexisting pressure sores worsened during pregnancy. Vaginal deliveries occurred in one in five pregnancies of women who were wheelchair dependent and in ten of eighteen pregnancies in independently mobile women, including seven of eight pregnancies of independently mobile women without ileal conduits. Cesarean sections were accompanied by postoperative complications in 10 women. Women with spina bifida who become pregnant generally have a positive outcome, with relatively low complication rates.

Perspectives of school-work transitions among youth with spina bifida, their parents and health care providers.

PubMed

Lindsay, Sally; McPherson, Amy C; Maxwell, Joanne

2017-04-01

Purpose Youth with disabilities encounter many challenges in finding employment and transitioning to post-secondary education. In this article, we explore the nature of school-work transitions for youth with spina bifida, which few studies have previously addressed. Method We conducted in-depth interviews with 44 participants (nine youth and 12 young adults with spina bifida, 11 parents and 12 clinicians). We analyzed our data using a qualitative content analysis approach. Results We identified several enablers to school-work transitions, including professional support, social support and school accommodations. Lacking such support created several challenges for youth with spina bifida. We also identified several barriers to school-work transitions, including lack of education and information on finances, housing and transportation; discrimination and stigma; and challenges coping with spina bifida at school and work. Conclusions Although some supports are available, youth with spina bifida encounter many challenges in transitioning to post-secondary education and employment. With clinicians at the helm, efforts should be put in place within the health and social services system to better prepare youth, as they transition to adulthood, to become connected to appropriate information and resources to help them to succeed in their school and employment goals. Implications for Rehabilitation Youth with spina bifida encounter many challenges in transitioning to post-secondary education or work. Clinicians, educators and parents should continue to support youth with spina bifida in choosing their vocations, setting career goals and developing career plans. Starting from a young age, parents, clinicians and educators should help youth with spina bifida prepare for school work transitions by fostering their independence, life skills and self-management of spina bifida-related symptoms. Clinicians and educators should help connect youth with spina bifida to appropriate

Health care expenditures of children and adults with spina bifida in a privately insured U.S. population.

PubMed

Ouyang, Lijing; Grosse, Scott D; Armour, Brian S; Waitzman, Norman J

2007-07-01

We provide new estimates of medical care utilization and expenditures over the lifespan for persons living with spina bifida in the United States. Updated estimates are essential for calculations of lifetime costs and for economic evaluations of prevention and management strategies for spina bifida. We analyzed data from the 2001-2003 MarketScan database on paid medical and prescription drug claims of persons covered by employer-sponsored health insurance in the United States. Medical care utilization and expenditures during 2003 were analyzed for persons with a diagnosis of spina bifida recorded during 2001-2003 who had 12 months of coverage in a fee-for-service health plan. To calculate expenditures during infancy, a separate analysis was performed for those born during 2002 with claims and expenditures data during the first 12 months of life. We compared medical expenditures for persons with and without spina bifida by age groups. Average incremental medical expenditures comparing patients with spina bifida and those without were $41,460 per year at age 0, $14,070 at ages 1-17, $13,339 at ages 18-44, and $10,134 at ages 45-64. Children ages 1-17 years with spina bifida had average medical expenditures 13 times greater than children without spina bifida. Adults with spina bifida had average medical expenditures three to six times greater than adults without spina bifida in this privately insured population. Although per capita medical care utilization and expenditures are highest among children, adults constitute an important and growing share of the population living with spina bifida. (c) 2007 Wiley-Liss, Inc.

Work Participation among Young Adults with Spina Bifida in the Netherlands

ERIC Educational Resources Information Center

Van Mechelen, M. C.; Verhoef, M.; Van Asbeck, F. W. A.; Post, M. W. M.

2008-01-01

The aim of this study was to: (1) assess work participation among young adults with spina bifida, (2) identify problems perceived in finding employment, and (3) examine which determinants are related to work participation. This cross-sectional study was a follow-up study to the Adolescents with SPina bifida In the Netherlands (ASPINE) study. Data…

Differences between the events preceding spina bifida and anencephaly.

PubMed

James, W H

1981-02-01

It is usually held that there is a time continuum in the formation of monoxygotic (MZ) twins which is indexed by their placentation, running from dichorionic to monochorionic diamniotic to monochorionic monoamniotic and conjoined pairs. There is good evidence that this continuum is characterised by a continuum of predisposition to anencephaly, slightly raised in dichorionic pairs but very high in some sorts of conjoined pairs. Although MZ twins, especially monoamniotic and conjoined pairs, are peculiarly liable to anencephaly, they are not particularly susceptible to spina bifida. Among twin pairs concordant for anencephaly or spina bifida, there are strikingly few concordant in the sense of one twin having anencephaly and the other spina bifida, in contrast with the numbers of pairs concordant for the same malformation. The prevalence of anencephaly in double monsters varies with the type of monster, being high in diprosopus. These findings may be explained by the timing of embryonic events.

Differences between the events preceding spina bifida and anencephaly.

PubMed Central

James, W H

1981-01-01

It is usually held that there is a time continuum in the formation of monoxygotic (MZ) twins which is indexed by their placentation, running from dichorionic to monochorionic diamniotic to monochorionic monoamniotic and conjoined pairs. There is good evidence that this continuum is characterised by a continuum of predisposition to anencephaly, slightly raised in dichorionic pairs but very high in some sorts of conjoined pairs. Although MZ twins, especially monoamniotic and conjoined pairs, are peculiarly liable to anencephaly, they are not particularly susceptible to spina bifida. Among twin pairs concordant for anencephaly or spina bifida, there are strikingly few concordant in the sense of one twin having anencephaly and the other spina bifida, in contrast with the numbers of pairs concordant for the same malformation. The prevalence of anencephaly in double monsters varies with the type of monster, being high in diprosopus. These findings may be explained by the timing of embryonic events. PMID:7019447

Living with Spina Bifida (at different ages)

MedlinePlus

... School-Aged Adolescents & Teens Young Adults Videos My Story Data and Statistics Research & Tracking Spina Bifida Patient Registry Clinic Map Findings from Patient Registry Articles & Key Findings Free ...

Social Implications of Spina Bifida.

ERIC Educational Resources Information Center

Woodburn, Margaret

Investigated in Southeast Scotland were the social and practical problems faced by the parents of 86 children (ages 18 months to 38 years) with spina bifida, 74 of whom were classified as myelomeningoceles (a more serious condition involving malformation of the spinal cord). Questionnaires and interviews were used to gather information in the…

Urologic Management of Spina Bifida

ERIC Educational Resources Information Center

Clayton, Douglass B.; Brock, John W., III; Joseph, David B.

2010-01-01

The urologist plays an important role in the multidisciplinary team of physicians who provide care for patients with spina bifida. We review common strategies for managing the urinary tract in these patients. The primary objective in all phases of life is protecting kidney function by minimizing bladder hostility and establishing a good capacity,…

Orthopedic Management of Spina Bifida

ERIC Educational Resources Information Center

Thomson, Jeffrey D.; Segal, Lee S.

2010-01-01

The management of orthopedic problems in spina bifida has seen a dramatic change over the past 10 years. The negative effects of spasticity, poor balance, and the tethered cord syndrome on ambulatory function are better appreciated. There is less emphasis on the hip radiograph and more emphasis on the function of the knee and the prevention of…

Optimizing health care for adults with spina bifida.

PubMed

Webb, Thomas S

2010-01-01

Survival into adulthood for individuals with spina bifida has significantly improved over the last 40 years with the majority of patients now living as adults. Despite this growing population of adult patients who have increased medical needs compared to the general population, including spina bifida (SB)-specific care, age-related secondary disabilities, and general adult medical needs, there is little published information about the natural history of SB in adulthood. There are few published studies of medical conditions, interventions, or long-term complications in this population. This article will provide a review of the medical issues of adults with SB, highlighting areas that are different than pediatric care, and areas of needed research.

Risky business: Preventing skin breakdown in children with spina bifida.

PubMed

Ekmark, Elaine McGarr

2009-01-01

The purpose of this article is to provide an overview of skin issues in children with spina bifida. Included in the discussion below is a review of the etiology of pressure ulcers and the updated 2007 pressure ulcer definition and pressure ulcer staging system as defined by the National Pressure Ulcer Advisory Panel (NPUAP). Pediatric risk factors for skin breakdown are presented including risk factors unique to children with spina bifida. Pediatric pressure ulcer risk assessment scales are described. The 5 Million Lives Kids' Campaign which has a focus on preventing hospital-acquired pressure ulcers in children is also reviewed along with evidence based prevention strategies. The key to preventing skin breakdown and pressure ulcers in children with spina bifida is early identification of the child's individual risk factors so that a prevention protocol can be implemented in all settings: hospital, home and the community. Options for wound management, dressing selection and pain management are included.

Cognitive Abilities of Pre- and Primary School Children with Spina Bifida in Uganda

ERIC Educational Resources Information Center

Bannink, Femke; Fontaine, Johnny R. J.; Idro, Richard; van Hove, Geert

2016-01-01

This study investigates cognitive abilities of pre/primary school children without and with spina bifida in Uganda. Qualitative semi structured interviews and quantitative functioning scales measurements were combined and conducted with 133 parents, 133 children with spina bifida, and 35 siblings. ANCOVA was used to test for differences in…

Hospitalization for urinary tract infections and the quality of preventive health care received by people with spina bifida.

PubMed

Armour, Brian S; Ouyang, Lijing; Thibadeau, Judy; Grosse, Scott D; Campbell, Vincent A; Joseph, David

2009-07-01

The preventive health care needs of people with disabilities often go unmet, resulting in medical complications that may require hospitalization. Such complications could be due, in part, to difficulty accessing care or the quality of ambulatory care services received. To use hospitalizations for urinary tract infections (UTIs) as a marker of the potential quality of ambulatory care services received by people affected by spina bifida. MarketScan inpatient and outpatient medical claims data for 2000 through 2003 were used to identify hospitalizations for UTI, which is an ambulatory care sensitive condition, for people affected by spina bifida and to calculate inpatient discharge rates, average lengths of stay, and average medical care expenditures for such hospitalizations. People affected by spina bifida averaged 0.5 hospitalizations per year, and there were 22.8 inpatient admissions with UTI per 1000 persons with spina bifida during the period 2000-2003, in comparison to an average of 0.44 admission with UTI per 1000 persons for those without spina bifida. If the number of UTI hospitalizations among people affected by spina bifida were reduced by 50%, expenditures could be reduced by $4.4 million per 1000 patients. Consensus on the evaluation and management of bacteriuria could enhance clinical care and reduce the disparity in UTI discharge rates among people affected by spina bifida compared to those without spina bifida. National evidence-based guidelines are needed.

Interhemispheric Effective and Functional Cortical Connectivity Signatures of Spina Bifida Are Consistent with Callosal Anomaly

PubMed Central

Malekpour, Sheida; Li, Zhimin; Cheung, Bing Leung Patrick; Castillo, Eduardo M.; Papanicolaou, Andrew C.; Kramer, Larry A.; Fletcher, Jack M.

2012-01-01

Abstract The impact of the posterior callosal anomalies associated with spina bifida on interhemispheric cortical connectivity is studied using a method for estimating cortical multivariable autoregressive models from scalp magnetoencephalography data. Interhemispheric effective and functional connectivity, measured using conditional Granger causality and coherence, respectively, is determined for the anterior and posterior cortical regions in a population of five spina bifida and five control subjects during a resting eyes-closed state. The estimated connectivity is shown to be consistent over the randomly selected subsets of the data for each subject. The posterior interhemispheric effective and functional connectivity and cortical power are significantly lower in the spina bifida group, a result that is consistent with posterior callosal anomalies. The anterior interhemispheric effective and functional connectivity are elevated in the spina bifida group, a result that may reflect compensatory mechanisms. In contrast, the intrahemispheric effective connectivity is comparable in the two groups. The differences between the spina bifida and control groups are most significant in the θ and α bands. PMID:22571349

Implementation of an inter-agency transition model for youth with spina bifida.

PubMed

Lindsay, S; Cruickshank, H; McPherson, A C; Maxwell, J

2016-03-01

To address gaps in transfer of care and transition support, a paediatric hospital and adult community health care centre partnered to implement an inter-agency transition model for youth with spina bifida. Our objective was to understand the enablers and challenges experienced in the implementation of the model. Using a descriptive, qualitative design, we conducted semi-structured interviews, in-person or over the phone, with 12 clinicians and nine key informants involved in implementing the spina bifida transition model. We recruited all 21 participants from an urban area of Ontario, Canada. Clinicians and key informants experienced several enablers and challenges in implementing the spina bifida transition model. Enablers included dedicated leadership, advocacy, funding, inter-agency partnerships, cross-appointed staff and gaps in co-ordinated care to connect youth to adult services. Challenges included gaps in the availability of adult specialty services, limited geographical catchment of adult services, limited engagement of front-line staff, gaps in communication and role clarity. Although the transition model has realized some initial successes, there are still many challenges to overcome in transferring youth with spina bifida to adult health care and transitioning to adulthood. © 2015 John Wiley & Sons Ltd.

Perception of secondary conditions in adults with spina bifida and impact on daily life.

PubMed

Wagner, Robert; Linroth, Ronna; Gangl, Candice; Mitchell, Nancy; Hall, Michelle; Cady, Rhonda; Christenson, Matthew

2015-10-01

Spina bifida is a congenital defect of the neural tube resulting in motor and sensory disruption. Persons with spina bifida can also experience executive function impairments. Secondary conditions are physical, medical, cognitive, emotional, or psychosocial consequences to which persons with disabilities are more susceptible. Our experience suggested clinicians underappreciate the presence and impact of secondary conditions in adults with spina bifida because they do not specifically ask for this information. Describe the presence and impact of secondary conditions on daily life, as perceived by adults with spina bifida. A clinic-based sample was recruited from the active patient population of an adult specialty center for spina bifida-related care. All subjects were verbally administered a survey developed through literature review and clinical experience of the researchers. The survey measured the presence and perceived impact of secondary conditions. Recruitment and survey data collection occurred over a 6-month period to maximize age representation. Survey data were stratified by age, gender and lesion level for analysis. Seventy-two respondents completed the survey. Pain was commonly reported, along with pressure ulcers, bowel & bladder concerns, depression, sleep disturbance, and limited social and community participation. No significant relationships were found between the presence or perceived impact of secondary conditions and age, gender or level of lesion. Secondary conditions in spina bifida are present by early adulthood. Identifying these conditions during clinical encounters requires specific rather than general questions. Future study should evaluate earlier initiation of preventative measures by pediatric providers. Copyright © 2015 Elsevier Inc. All rights reserved.

Characteristics and survival of patients with end stage renal disease and spina bifida in the United States renal data system.

PubMed

Ouyang, Lijing; Bolen, Julie; Valdez, Rodolfo; Joseph, David; Baum, Michelle A; Thibadeau, Judy

2015-02-01

We describe the characteristics, treatments and survival of patients with spina bifida in whom end stage renal disease developed from 2004 through 2008 in the United States Renal Data System. We used ICD-9-CM code 741.* to identify individuals with spina bifida using hospital inpatient data from 1977 to 2010, and physician and facility claims from 2004 to 2008. We constructed a 5:1 comparison group of patients with end stage renal disease without spina bifida matched by age at first end stage renal disease service, gender and race/ethnicity. We assessed the risk of mortality and of renal transplantation while on dialysis using multivariate cause specific proportional hazards survival analysis. We also compared survival after the first renal transplant from the first end stage renal disease service to August 2011. We identified 439 patients with end stage renal disease and spina bifida in whom end stage renal disease developed at an average younger age than in patients without spina bifida (41 vs 62 years, p <0.001) and in whom urological issues were the most common primary cause of end stage renal disease. Compared to patients with end stage renal disease without spina bifida those who had spina bifida showed a similar mortality hazard on dialysis and after transplantation. However, patients with end stage renal disease without spina bifida were more likely to undergo renal transplantation than patients with spina bifida (HR 1.51, 95% CI 1.13-2.03). Hospitalizations related to urinary tract infections were positively associated with the risk of death on dialysis in patients with end stage renal disease and spina bifida (HR 1.42, 95% CI 1.33-1.53). Spina bifida was not associated with increased mortality in patients with end stage renal disease on dialysis or after renal transplantation. Proper urological and bladder management is imperative in patients with spina bifida, particularly in adults. Copyright © 2015 American Urological Association Education and

Genetic variation in biotransformation enzymes, air pollution exposures, and risk of spina bifida.

PubMed

Padula, Amy M; Yang, Wei; Schultz, Kathleen; Lurmann, Fred; Hammond, S Katharine; Shaw, Gary M

2018-05-01

Spina bifida is a birth defect characterized by incomplete closure of the embryonic neural tube. Genetic factors as well as environmental factors have been observed to influence risks for spina bifida. Few studies have investigated possible gene-environment interactions that could contribute to spina bifida risk. The aim of this study is to examine the interaction between gene variants in biotransformation enzyme pathways and ambient air pollution exposures and risk of spina bifida. We evaluated the role of air pollution exposure during pregnancy and gene variants of biotransformation enzymes from bloodspots and buccal cells in a California population-based case-control (86 cases of spina bifida and 208 non-malformed controls) study. We considered race/ethnicity and folic acid vitamin use as potential effect modifiers and adjusted for those factors and smoking. We observed gene-environment interactions between each of the five pollutants and several gene variants: NO (ABCC2), NO 2 (ABCC2, SLC01B1), PM 10 (ABCC2, CYP1A1, CYP2B6, CYP2C19, CYP2D6, NAT2, SLC01B1, SLC01B3), PM 2.5 (CYP1A1 and CYP1A2). These analyses show positive interactions between air pollution exposure during early pregnancy and gene variants associated with metabolizing enzymes. These exploratory results suggest that some individuals based on their genetic background may be more susceptible to the adverse effects of pollution. © 2018 Wiley Periodicals, Inc.

Factors Associated with Mobility Outcomes in a National Spina Bifida Patient Registry

PubMed Central

Dicianno, Brad E.; Karmarkar, Amol; Houtrow, Amy; Crytzer, Theresa M.; Cushanick, Katelyn M.; McCoy, Andrew; Wilson, Pamela; Chinarian, James; Neufeld, Jacob; Smith, Kathryn; Collins, Diane M.

2017-01-01

Objective To provide descriptive data on ambulatory ability and muscle strength in a large cohort of individuals with spina bifida enrolled in a National Spina Bifida Patient Registry (NSBPR) and to investigate factors associated with ambulatory status. Design Cross-sectional analysis of data from a multi-site patient registry Results Descriptive analysis of mobility variables for 2604 individuals with spina bifida age 5 and above are presented from 19 sites in the United States. Analysis of a subset of NSBPR data from 380 individuals from three sites accompanied by data from a specialized spina bifida electronic medical record revealed that those with no history of a shunt, lower motor level, and no history of hip or knee contracture release surgery were more likely to be ambulatory at the community level than at the household or wheelchair level. Conclusion This study is the first to examine factors associated with ambulatory status in a large sample of individuals with myelomeningocele and non-myelomeningocele subtypes of SB. Results of this study delineate the breadth of strength and functional abilities within the different age groups and subtypes of SB. The results may inform clinicians of the characteristics of those with varying ambulatory abilities. PMID:26488146

The longest faun tail forming dreadlocks with underlying spina bifida occulta.

PubMed

Brar, Balvinder Kaur; Mahajan, Bharat Bhushan; Mittal, Jyotisterna

2013-04-15

Spina bifida is a developmental anomaly characterized by defective closure of the bony encasement of the spinal cord through which the spinal cord and meninges may or may not protrude. We report a rare case of a very long faun tail, which was in the form of a 20 inch long tail originating from the lumbosacral area in a rhomboidal pattern, measuring 10 x 8 inches. The case is being reported for its rare presentation of a 20 inch long faun tail with underlying spina bifida occulta.

Labor market productivity costs for caregivers of children with spina bifida: a population-based analysis.

PubMed

Tilford, John M; Grosse, Scott D; Goodman, Allen C; Li, Kemeng

2009-01-01

Caregiver productivity costs are an important component of the overall cost of care for individuals with birth defects and developmental disabilities, yet few studies provide estimates for use in economic evaluations. This study estimates labor market productivity costs for caregivers of children and adolescents with spina bifida. Case families were recruited from a state birth defects registry in Arkansas. Primary caregivers of children with spina bifida (N = 98) reported their employment status in the past year and demographic characteristics. Controls were abstracted from the Current Population Survey covering the state of Arkansas for the same time period (N = 416). Estimates from regression analyses of labor market outcomes were used to calculate differences in hours worked per week and lifetime costs. Caregivers of children with spina bifida worked an annual average of 7.5 to 11.3 hours less per week depending on the disability severity. Differences in work hours by caregivers of children with spina bifida translated into lifetime costs of $133,755 in 2002 dollars using a 3% discount rate and an age- and sex-adjusted earnings profile. Including caregivers' labor market productivity costs in prevention effectiveness estimates raises the net cost savings per averted case of spina bifida by 48% over the medical care costs alone. Information on labor market productivity costs for caregivers can be used to better inform economic evaluations of prevention and treatment strategies for spina bifida. Cost-effectiveness calculations that omit caregiver productivity costs substantially overstate the net costs of the intervention and underestimate societal value.

The Spina Bifida Child in the Classroom.

ERIC Educational Resources Information Center

Mattson, Beverly; And Others

Learning characteristics of children with spina bifida (lesions on the spinal cord) are reviewed in the text of a presentation with slides, and the effects of such factors as hospitalization experiences and the presence of hydrocephalus are considered. Characteristics related to intelligence, sensory integration, tactile responsiveness, tactile…

Neurosurgical Management of Spina Bifida: Research Issues

ERIC Educational Resources Information Center

Bowman, Robin M.; McLone, David G.

2010-01-01

The neurosurgical goal when treating children with spina bifida (predominantly myelomeningocele) is to maintain stable neurological functioning throughout the patient's life time. Unfortunately, few long-term outcome studies are available to help direct the neurosurgical care of a child born with myelomeningocele and often treatment relies more…

Erector spinae plane block for analgesia after lower segment caesarean section: Case report.

PubMed

Yamak Altinpulluk, E; García Simón, D; Fajardo-Pérez, M

2018-05-01

Effective postoperative analgesia after emergency caesarean section is important because it provides early recovery, ambulation and breast-feeding. The ultrasound-guided erector spinae plane block has been orginally described for providing thoracic analgesia at the T5 transverse process by Forero et al. We performed post-operative bilateral erector spinae plane blocks with 20ml bupivacaine 0.25% at the level of the T9 transverse process in a pregnant woman after caesarean section. In this report, we described that bilateral erector spinae plane block at T9 level provides effective and long-lasting postoperative analgesia for lower abdominal surgery. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Impact of Spina Bifida on Parental Caregivers: Findings from a Survey of Arkansas Families

ERIC Educational Resources Information Center

Grosse, Scott D.; Flores, Alina L.; Ouyang, Lijing; Robbins, James M.; Tilford, John M.

2009-01-01

The well-being of caregivers of children with spina bifida and other conditions is an important topic. We interviewed the primary caregivers of 98 children aged 0-17 years with spina bifida sampled from a population-based birth defects registry in Arkansas and the caregivers of 49 unaffected children. Measures of caregiver well-being were compared…

Community Knowledge, Beliefs, Attitudes, and Practices towards Children with Spina Bifida and Hydrocephalus in Uganda

ERIC Educational Resources Information Center

Bannink, Femke; Stroeken, Koenraad; Idro, Richard; van Hove, Geert

2015-01-01

This article describes the findings of a qualitative study on knowledge, beliefs, attitudes, and practices towards children with spina bifida and hydrocephalus in four regions of Uganda. Focus group discussions and semi-structured interviews were held with parents of children with spina bifida and hydrocephalus, policy-makers, and service…

Psychosocial and Family Functioning in Spina Bifida

ERIC Educational Resources Information Center

Holmbeck, Grayson N.; Devine, Katie A.

2010-01-01

A developmentally oriented bio-neuropsychosocial model is introduced to explain the variation in family functioning and psychosocial adjustment in youth and young adults with spina bifida (SB). Research on the family functioning and psychosocial adjustment of individuals with SB is reviewed. The findings of past research on families of youth with…

Projected number of children with isolated spina bifida or down syndrome in England and Wales by 2020.

PubMed

Best, Kate E; Glinianaia, Svetlana V; Lingam, Raghu; Morris, Joan K; Rankin, Judith

2018-05-19

Children with major congenital anomalies often require lifelong access to health and social care services. Estimating future numbers of affected individuals can aid health and social care planning. This study aimed to estimate the number of children aged 0-15 years living with spina bifida or Down syndrome in England and Wales by 2020. Cases of spina bifida and Down syndrome born during 1998-2013 were identified from the Northern Congenital Abnormality Survey and the National Down Syndrome Cytogenetic Register, respectively. The number of infants born with spina bifida during 1998-2019 were estimated by applying the average prevalence rate in the North of England to actual and projected births in England and Wales. Poisson regression was performed to estimate the number of infants born with Down syndrome in England and Wales during 1998-2013 and 2004-2019. The numbers of children aged 0-15 living with spina bifida or Down syndrome in 2014 and in 2020 were then estimated by multiplying year- and age-specific survival estimates by the number of affected births. An estimated 956 children with isolated spina bifida, 623 children with spina bifida and hydrocephalus and 11,592 children with Down syndrome aged 0-15 years will be living in England and Wales by 2020, increases of 7.2%, 12.0% and 12.7% since 2014, respectively. Due to improvements in survival, an increase in population size and changes in maternal age distribution at delivery, we anticipate further increases in the number of children living with spina bifida or Down syndrome by 2020. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Are There Disorders or Conditions Associated with Spina Bifida?

MedlinePlus

... have shunts and have had many surgeries. 2 Learning Disabilities While at least 80% of children with open spina bifida do not have learning deficiencies, some do have learning problems. 3 Other ...

[Spina bifida occulta associated with environmental arsenic exposure in a prehispanic sample from northern Chile].

PubMed

Silva-Pinto, Verónica; Arriaza, Bernardo; Standen, Vivien

2010-04-01

The Camarones River Valley, located in the extreme north of Chile, is characterized by high environmental arsenic levels and an arid desert. It has been inhabited by humans for the past 7,000 years. Evidence exists for chronic arsenic poisoning in both prehispanic and present populations residing in the area. Chronic arsenic exposure causes multi-systemic problems and can induce congenital malformations, in particular neural tube development defects such as spina bifida. To study the prevalence of spina bifida among prehispanic mummies of the area. One hundred and twenty prehistoric adult individuals were analyzed for evidence of spina bifda occulta of the sacrum in skeletal samples from the sites of Camarones 8, Camarones 9, Azapa 140 and Lluta 54, held in repository at the Museo Universidad de Tarapacá de Arica- San Miguel de Azapa. A diagnosis was considered positive when at least S1, S2 or S3 were affected. As controls, mummies of individuals that resided in Lluta and Azapa valley, with a low arsenic exposure, were analyzed. The frequency of spina bifida occulta among samples from the Camarones coast and Lluta and Azapa Valley were 13.5 and 2.4% respectively. Considering these were contemporaneous samples, and are believed to have had no other differences in diet or other factors, the differential exposures to arsenic could have produced the observed differences in spina bifida frequencies.

38 CFR 3.814 - Monetary allowance under 38 U.S.C. chapter 18 for an individual suffering from spina bifida whose...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 38 U.S.C. chapter 18 for an individual suffering from spina bifida whose biological father or mother... for an individual suffering from spina bifida whose biological father or mother is or was a Vietnam... an individual suffering from spina bifida whose biological mother or father is or was a Vietnam...

38 CFR 3.814 - Monetary allowance under 38 U.S.C. chapter 18 for an individual suffering from spina bifida whose...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 38 U.S.C. chapter 18 for an individual suffering from spina bifida whose biological father or mother... spina bifida whose biological father or mother is or was a Vietnam veteran. (a) Monthly monetary... person who VA has determined is an individual suffering from spina bifida whose biological mother or...

Effects of spine flexion and erector spinae maximal force on vertical squat jump height: a computational simulation study.

PubMed

Blache, Yoann; Monteil, Karine

2015-03-01

The purpose of this study was to evaluate the single and combined effects of initial spine flexion and maximal isometric force of the erector spinae on maximal vertical jump height during maximal squat jumping. Seven initial flexions of the 'thorax-head-arm' segment (between 20.1° and 71.6°) and five maximal isometric forces of the erector spinae (between 5600 and 8600 N) were tested. Thus, 35 squat jumps were simulated using a 2D simulation model of the musculoskeletal system. Vertical jump height varied at most about 0.094 and 0.021 m when the initial flexion of the 'thorax-head-arm' segment and the maximal force of the erector spinae were, respectively, maximal. These results were explained for the most part by the variation of total muscle work. The latter was mainly influenced by the work produced by the erector spinae which increased at most about 57 and 110 J when the initial flexion of the 'thorax-head-arm' segment and the maximal force of the erector spinae were, respectively, maximal. It was concluded that the increase in the initial flexion of the 'thorax-head-arm' segment and in the maximal isometric force of the erector spinae enables an increase in maximal vertical jump height during maximal squat jumping.

Update on Urological Management of Spina Bifida from Prenatal Diagnosis to Adulthood.

PubMed

Snow-Lisy, Devon C; Yerkes, Elizabeth B; Cheng, Earl Y

2015-08-01

We review the current literature regarding urological management of spina bifida from prenatal diagnosis to adulthood. We searched MEDLINE(®), EMBASE(®) and PubMed(®) for English articles published through December 2014 using search terms "spina bifida," "spinal dysraphism" and "bladder." Based on review of titles and abstracts, 437 of 1,869 articles were identified as addressing topics related to open spina bifida in pediatric patients, or long-term or quality of life outcomes in adults with spina bifida. We summarize this literature to inform clinical guidelines and create a framework for disease management. The birth prevalence of spina bifida in the United States has recently plateaued at approximately 30 per 100,000. With improved management more individuals are surviving to adulthood, with an economic impact of $319,000 during the lifetime of an individual with spina bifida. Recent advances in prenatal surgery have demonstrated that prenatal closure of spina bifida is possible. To assess safety and efficacy, the National Institutes of Health sponsored Management of Myelomeningocele Study was undertaken, in which subjects were randomized to prenatal or postnatal closure. Until the urological results of this trial are published, the impact of prenatal intervention on future bladder function remains unclear. Controversy continues regarding the optimal use and timing of urodynamic studies, and the indications for initiation of clean intermittent catheterization and anticholinergics in infants and children. Many favor expectant management, while others argue for a more proactive approach. Based on the current literature, both approaches appear to protect the child from renal injury, although delayed intervention may increase rates of bladder augmentation. The current literature regarding this topic is difficult to interpret and compare due to heterogeneity of patient populations, variable outcome measures and lack of reporting of quality of life outcomes

Impairment of a Motor Skill in Children with Spina Bifida Cystica and Hydrocephalus: An Exploratory Study

ERIC Educational Resources Information Center

Anderson, Elizabeth M.; Plewis, Ian

1977-01-01

Twenty 7-10 year old children with spina bifida cystica and hydrocephalus and 20 normals matched for age, sex and IQ were compared on a 12-trial target task, first used by Connolly, Brown & Bassett (1968). Findings are discussed in relation to neurological abnormalities in the spina bifida group. (Editor/RK)

Treatment of pressure sores in spina bifida patients with calcium alginate and foam dressings.

PubMed

Ausili, E; Paolucci, V; Triarico, S; Maestrini, C; Murolo, D; Focarelli, B; Rendeli, C

2013-06-01

Prospective study on local treatment of pressure sores using calcium alginate and foam dressings in spina bifida patients. Investigate if this sequential approach is valid and safe for selected patients with neurological impairments. Using European Pressure Ulcer Grading System, after clinical evaluation of local sore, selected patients of Spina Bifida Center of Rome were treated with sequential calcium alginate and foam dressings for 12 weeks. Pressure ulcere surfaces were measured monthly by ulcer tracing. The endpoints were the mean absolute areas surface reduction during every month and number of patients achieving a 50% or more during study. 14 patients (7 males aged 12-24 years) with spina bifida and pressure sores were treated. Mean and standard deviation of mean surface area reduction were 12.5 ± 7.5 cm 2 at start of the study versus 3.7 ± 5.2 cm 2 after 12 weeks, p < 0.001. 75% of the patients reached mean surface area reduction of 50% during trial. Dressing tolerance was good in every patient. Calcium alginate and foam dressings are valid and safe approach in the treatment of pressure sores in selected patients with spina bifida. In fact, they protect the wound and create an environment favorable to healing.

Fetal surgery for spina bifida: past, present, future.

PubMed

Adzick, N Scott

2013-02-01

Open spina bifida or myelomeningocele (MMC) is a common birth defect that is associated with significant lifelong morbidity. Little progress has been made in the postnatal surgical management of the child with spina bifida. Postnatal surgery is aimed at covering the exposed spinal cord, preventing infection, and treating hydrocephalus with a ventricular shunt. Experimental and clinical evidence suggest that the primary cause of the neurologic defects associated with MMC is not simply incomplete neurulation, but rather chronic, mechanical and amniotic-fluid induced chemical trauma that progressively damages the exposed neural tissue during gestation. The cerebrospinal fluid leak through the MMC leads to hindbrain herniation and hydrocephalus. In utero repair of open spina bifida is now performed in selected patients and presents an additional therapeutic alternative for expectant mothers carrying a fetus with MMC. In the past, studies in animal models and clinical case series laid the groundwork for a clinical trial to test the safety and efficacy of fetal MMC repair. In the present, a prospective, randomized study (the MOMS trial) has shown that fetal surgery for MMC before 26 weeks' gestation may preserve neurologic function, reverse the hindbrain herniation of the Chiari II malformation, and obviate the need for postnatal placement of a ventriculoperitoneal shunt. However, this study also demonstrates that fetal surgery is associated with significant risks related to the uterine scar and premature birth. In the future, research will expand our understanding of the pathophysiology of MMC, evaluate the long-term impact of in-utero intervention, and to refine timing and technique of fetal MMC surgery using tissue engineering technology. Copyright © 2013 Elsevier Inc. All rights reserved.

An Approach for Determining Quantitative Measures for Bone Volume and Bone Mass in the Pediatric Spina Bifida Population

PubMed Central

Horenstein, Rachel E.; Shefelbine, Sandra J.; Mueske, Nicole M.; Fisher, Carissa L.; Wren, Tishya A.L.

2015-01-01

Background The pediatric spina bifida population suffers from decreased mobility and recurrent fractures. This study aimed to develop a method for quantifying bone mass along the entire tibia in youth with spina bifida. This will provide information about all potential sites of bone deficiencies. Methods Computed tomography images of the tibia for 257 children (n=80 ambulatory spina bifida, n=10 non-ambulatory spina bifida, n=167 typically developing) were analyzed. Bone area was calculated at regular intervals along the entire tibia length and then weighted by calibrated pixel intensity for density weighted bone area. Integrals of density weighted bone area were used to quantify bone mass in the proximal and distal epiphyses and diaphysis. Group differences were evaluated using analysis of variance. Findings Non-ambulatory children suffer from decreased bone mass in the diaphysis and proximal and distal epiphyses compared to ambulatory and control children (P≤0.001). Ambulatory children with spina bifida showed statistically insignificant differences in bone mass in comparison to typically developing children at these sites (P>0.5). Interpretation This method provides insight into tibial bone mass distribution in the pediatric spina bifida population by incorporating information along the whole length of the bone, thereby providing more information than dual-energy x-ray absorptiometry and peripheral quantitative computed tomography. This method can be applied to any population to assess bone mass distribution across the length of any long bone. PMID:26002057

38 CFR 21.8012 - Vocational training program for certain children of Vietnam veterans-spina bifida and covered...

Code of Federal Regulations, 2010 CFR

2010-07-01

... program for certain children of Vietnam veterans-spina bifida and covered birth defects. 21.8012 Section... REHABILITATION AND EDUCATION Vocational Training and Rehabilitation for Certain Children of Vietnam Veterans... children of Vietnam veterans—spina bifida and covered birth defects. VA will provide an evaluation to an...

Spina Bifida: General Information. Fact Sheet Number 12 = La Espina Bifida: Informacion General. Fact Sheet Number 12.

ERIC Educational Resources Information Center

National Information Center for Children and Youth with Disabilities, Washington, DC.

This fact sheet offers definitions of the three types of spina bifida, outlines their incidence, describes characteristics of individuals with spina bifida, and reviews educational implications. The fact sheet emphasizes that school programs should be flexible to accommodate these students' special needs and frequent absences, that children with…

Exploring psychosocial correlates of physical activity among children and adolescents with spina bifida.

PubMed

Marques, Adilson; Maldonado, Inês; Peralta, Miguel; Santos, Sofia

2015-01-01

To enhance physical activity of children with spina bifida, it is important to investigate the correlates of physical activity to support the development of interventions to promote active lifestyles. This study aimed to identify psychosocial correlates of physical activity among children and adolescents with spina bifida. A survey was conducted with 31 students (15 boys), aged 10-17 years with spina bifida. A questionnaire was used to collect data of physical activity, demographic and psychosocial variables (attitudes, sports goal orientation and perceptions). Unadjusted and adjusted binary logistic regressions were performed to examine the relationship of psychosocial factors and physical activity participation. Data were collected in 2013. Only 38.7% reported to participate in both organized and non-organized physical activity. Results showed no relationship between participation in organized and non-organized physical activity and psychosocial correlates. The result of the adjusted regression analysis show that perception of competence (OR = 9.55, 1.06-85.99, p < 0.05) was the only variable positively associated with participation in non-organized physical activity. Most of the participants reported that they did not participate in physical activity regularly. Psychosocial variables were not related with physical activity, except perception of competence. Studies with bigger samples are needed, focused on the same and in others factors to identify the predictors of physical activity of young people with spina bifida. Copyright © 2015 Elsevier Inc. All rights reserved.

Observations of a Father: My Son Has Spina Bifida.

ERIC Educational Resources Information Center

Remmel, Carl L.

1982-01-01

The author reviews his experiences as the father of a child with spina bifida, a congenital problem in which the spine is not completely enclosed. He recounts his feelings upon first finding out about the condition and his son's subsequent surgeries and crises. (CL)

Adult consequences of spina bifida: a cohort study.

PubMed

Roach, James W; Short, Barbara F; Saltzman, Hanna M

2011-05-01

Patients with spina bifida potentially experience social isolation with limited employment opportunities and restriction of independent living, neurologic and intellectual impairment, and orthopaedic and urologic consequences of their condition. However, the degree of disability as these individuals age into adulthood has not been completely delineated. In adults with spina bifida we determined the cause of death for those who had died, IQ, level of education, work history, independent living status, physical disabilities, and urologic status; we then identified surgical procedures that led to better adult function. We retrospectively reviewed 84 individuals with myelomeningocele, examining social, cognitive, and physical disabilities. The minimum age at followup was 20 years (mean, 31 years; range, 20-64 years). Forty-two percent had normal IQs. Seventy percent never needed a neurosurgical shunt and those without shunts had higher IQs. Forty-four percent had regular education and 8% achieved college degrees. Fifty-six percent were unemployed. Thirty percent lived independently. Twenty-three percent were either married or divorced with nine normal offspring. Eighty-five percent dressed themselves, 65% shopped independently, 54% drove. Thirty-one percent were at the thoracic neurologic level (all used wheelchairs), 12% were at L1-L3 (all used a wheelchair except one), 33% were at L4-L5 (78% used a wheelchair at least part-time), and 24% were at S1 and below (all walked). Fifty-four percent experienced decubiti and as a consequence, four required major extremity amputations. Spinal fusions protected sitting balance, but hip surgery did not produce congruent hips and occasionally resulted in debilitating stiffness. Pressure sores resulted in partial foot amputations despite plantigrade feet. Our observations confirm the consequences associated with the physical and cognitive disabilities of patients with spina bifida. Many of these consequences can likely be mitigated

Longitudinal mediators of social problem solving in spina bifida and typical development.

PubMed

Landry, Susan H; Taylor, Heather B; Swank, Paul R; Barnes, Marcia; Juranek, Jenifer

2013-05-01

The current study examined the role of early executive functions (EF) and social language (SL) as well as responsive parenting as mediators of the effect of group on social problem-solving skills at 7 years of age for children with spina bifida and typically developing children. A mediation analysis was used to determine if the effect of having spina bifida on school age social problem-solving skills was mediated through the effect of group on EF/SL at 3 years of age and responsive parenting at 12 and 18 months. As part of a larger longitudinal study, 103 infants (n = 49 with spina bifida; n = 54 typically developing) received measures of EF/SL at 3 years of age and mother-infant play interactions at 12 and 18 months of age were coded for a range of responsive parenting behaviors. Social problem-solving skills were measured with a game-like observational task at 7 years of age. Group had a direct relation with later social problem-solving as well as an indirect relation through early EF/SL skills that, in turn, had a direct relation with later social problem solving. An indirect effect of responsive parenting on later social skills also was found through a direct effect on EF/SL skills. Early precursors of school age difficulties with social problem solving observed for children with spina bifida can be explained, in part, by difficulties in the first 3 years of life with EF/SL. Early responsive parenting appears to positively affect the development of these EF/SL skills. Implications for early intervention are an outcome of this study.

Comparison of Thoracic and Lumbar Erector Spinae Muscle Activation Before and After a Golf Practice Session.

PubMed

Sorbie, Graeme G; Grace, Fergal M; Gu, Yaodong; Baker, Julien S; Ugbolue, Ukadike C

2017-08-01

Lower back pain is commonly associated with golfers. The study aimed: to determine whether thoracic- and lumbar-erector-spinae muscle display signs of muscular fatigue after completing a golf practice session, and to examine the effect of the completed practice session on club head speed, ball speed and absolute carry distance performance variables. Fourteen right-handed male golfers participated in the laboratory-based-study. Surface electromyography (EMG) data was collected from the lead and trail sides of the thoracic- and lumbar-erector-spinae muscle. Normalized root mean squared (RMS) EMG activation levels and performance variables for the golf swings were compared before and after the session. Fatigue was assessed using median frequency (MDF) and RMS during the maximum voluntary contraction (MVC) performed before and after the session. No significant differences were observed in RMS thoracic- and lumbar-erector-spinae muscle activation levels during the five phases of the golf swing and performance variables before and after the session (p > .05). Significant changes were displayed in MDF and RMS when comparing the MVC performed before and after the session (p < .05). Fatigue was evident in the trail side of the erector-spinae muscle after the session.

An environmental scan of weight assessment and management practices in paediatric spina bifida clinics across Canada.

PubMed

McPherson, Amy C; Leo, Jennifer; Church, Paige; Lyons, Julia; Chen, Lorry; Swift, Judy

2014-01-01

Childhood obesity is a global health concern, but children with spina bifida in particular have unique interacting risk factors for increased weight. To identify and explore current clinical practices around weight assessment and management in pediatric spina bifida clinics. An online, self-report survey of healthcare professionals (HCPs) was conducted in all pediatric spina bifida clinics across Canada (15 clinics). Summary and descriptive statistics were calculated and descriptive thematic analysis was performed on free text responses. 52 responses across all 15 clinics indicated that weight and height were assessed and recorded most of the time using a wide variety of methods, although some HCPs questioned their suitability for children with spina bifida. Weight and height information was not routinely communicated to patients and their families and HCPS identified considerable barriers to discussing weight-related information in consultations. Despite weight and height reportedly being measured regularly, HCPs expressed concern over the lack of appropriate assessment and classification tools. Communication across multi-disciplinary team members is required to ensure that children with weight-related issues do not inadvertently get overlooked. Specific skill training around weight-related issues and optimizing consultation time should be explored further for HCPs working with this population.

The Infant and Young Child with Spina Bifida: Major Medical Concerns.

ERIC Educational Resources Information Center

Shaer, Catherine M.

1997-01-01

This review of medical concerns in dealing with spina bifida examines neurologic and neurosurgical issues, learning issues, urological dysfunction, orthopedic issues, bowel control, latex allergy, and prenatal diagnosis and prevention. (JDD)

The Use of Liposomal Bupivacaine in Erector Spinae Plane Block to Minimize Opioid Consumption for Breast Surgery: A Case Report.

PubMed

Kumar, Amanda; Hulsey, Alina; Martinez-Wilson, Hector; Kim, James; Gadsden, Jeff

2018-05-01

The erector spinae plane block is a novel interfascial plane block that can provide thoracic and abdominal analgesia. We describe a patient with opioid intolerance scheduled for breast surgery who received an erector spinae plane block with liposomal bupivacaine as well as a supplemental T1 paravertebral block resulting in profound analgesia throughout her postoperative course. This case report demonstrates that use of liposomal bupivacaine in the erector spinae plane block can be successful in providing extended duration postoperative analgesia and minimizing systemic opioid requirements.

The Use of Liposomal Bupivacaine in Erector Spinae Plane Block to Minimize Opioid Consumption for Breast Surgery: A Case Report.

PubMed

Kumar, Amanda; Hulsey, Alina; Martinez-Wilson, Hector; Kim, James; Gadsden, Jeff

2017-11-16

The erector spinae plane block is a novel interfascial plane block that can provide thoracic and abdominal analgesia. We describe a patient with opioid intolerance scheduled for breast surgery who received an erector spinae plane block with liposomal bupivacaine as well as a supplemental T1 paravertebral block resulting in profound analgesia throughout her postoperative course. This case report demonstrates that use of liposomal bupivacaine in the erector spinae plane block can be successful in providing extended duration postoperative analgesia and minimizing systemic opioid requirements.

First-trimester visualization of the fourth ventricle in fetuses with and without spina bifida.

PubMed

Solt, Ido; Acuna, Joann G; Adeniji, Beni A; Mirocha, James; Kim, Matthew J; Rotmensch, Siegfried

2011-12-01

The purpose of this study was to examine the efficacy of nonvisualization of the fourth ventricle for first-trimester detection of spina bifida. A total of 250 digitally stored sonographic examinations at gestational ages of 11 weeks to 13 weeks 6 days (245 normal and 5 randomly interspersed spina bifida cases) were retrospectively analyzed by 4 blinded reviewers for the presence or absence of the fourth ventricle followed by an anteroposterior ventricular dimension measurement. The ventricle size was related to the crown-rump length and gestational age by linear regression analysis and Pearson correlation. The fourth ventricle was identified in 971 of 1000 image readings (97.1%). False-negative and false-positive readings occurred in 11 of 20 (55.0%) and 20 of 980 (2.0%) cases, respectively (sensitivity, 0.45; specificity, 0.98.). False-negative and false-positive readings were evenly distributed throughout the gestational age range. When the ventricular size was measurable, its mean dimensions increased linearly with gestational age and were below the fifth percentile in 10 of 245 (4.0%) normal and 0 of 4 spina bifida cases, respectively. Intraclass correlation coefficient estimates were calculated based on the 2-way analysis of variance model and found to be 0.30 for a single rater and 0.64 for the mean of 4 raters. Nonvisualization of the first-trimester fourth ventricle is a less robust screening parameter for spina bifida than previously published.

Paternal and joint parental occupational pesticide exposure and spina bifida in the National Birth Defects Prevention Study, 1997 to 2002.

PubMed

Pettigrew, Stacy M; Bell, Erin M; Van Zutphen, Alissa R; Rocheleau, Carissa M; Shaw, Gary M; Romitti, Paul A; Olshan, Andrew; Lupo, Philip J; Soim, Aida; Makelarski, Jennifer A; Michalski, Adrian M; Sanderson, Wayne

2016-11-01

Because of persistent concerns over the association between pesticides and spina bifida, we examined the role of paternal and combined parental occupational pesticide exposures in spina bifida in offspring using data from a large population-based study of birth defects. Occupational information from fathers of 291 spina bifida cases and 2745 unaffected live born control infants with estimated dates of delivery from 1997 to 2002 were collected by means of maternal report. Two expert industrial hygienists estimated exposure intensity and frequency to insecticides, herbicides, and fungicides. Multivariable logistic regression models were used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for exposure to any pesticide and to any class of pesticide (yes/no; and by median), and exposure to combinations of pesticides (yes/no) and risk of spina bifida. Adjusted odds ratios were also estimated by parent exposed to pesticides (neither, mother only, father only, both parents). Joint parental occupational pesticide exposure was positively associated with spina bifida (aOR, 1.5; 95% CI, 0.9-2.4) when compared with infants with neither maternal nor paternal exposures; a similar association was not observed when only one parent was exposed. There was a suggested positive association between combined paternal insecticide and fungicide exposures and spina bifida (aOR, 1.5; 95% CI, 0.8-2.8), however, nearly all other aORs were close to unity. Overall, there was little evidence paternal occupational pesticide exposure was associated with spina bifida. However, the small numbers make it difficult to precisely evaluate the role of pesticide classes, individually and in combination. Birth Defects Research (Part A) 106:963-971, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Maternal occupational exposure during pregnancy and the risk of spina bifida.

PubMed Central

Blatter, B M; Roeleveld, N; Zielhuis, G A; Gabreëls, F J; Verbeek, A L

1996-01-01

OBJECTIVES: A case-control study was carried out to explore associations between spina bifida and occupational exposure of the mother. METHODS: The cases were children with spina bifida aperta born between 1980 and 1992 from nine hospitals in the Netherlands. The controls were children born healthy in the same period as the cases, from hospitals and from the general population. Data collection was carried out in two steps. Firstly, postal questionnaires were sent to all the parents of cases and controls to gather information on occupations and potential confounders. In the second phase of the study, information on specific exposures was collected by means of job and task specific personal interviews. Interviews were performed with 55 case mothers and 66 control mothers who had occupations with a potential for chemical or physical exposure. Those exposures were assumed to be negligible for--for example, teachers and secretaries, so personal interviews were not indicated for these women. Information was collected on specific tasks in the period just after conception, and on the associated use of chemical or physical agents, frequency of exposure, and use of protective equipment. RESULTS: The analyses of occupation showed an increased risk for women working in agricultural occupations (OR = 3.4, CI:1.3-9.0), and, although less distinct, for cleaning women (OR = 1.7, CI:0.9-3.4). Only a few women seemed to be occupationally exposed to chemical or physical agents. No differences in occurrence of specific exposures could be detected between cases and controls. Besides, no differences were seen in pesticide or disinfectant exposure among case and control mothers in agricultural occupations. CONCLUSIONS: Occupational exposures of the mother during pregnancy were infrequent and did not seem to play an important part in the aetiology of spina bifida in this study. The association found between spina bifida and maternal agricultural occupations could not be explained by the

Effect of bladder augmentation on VP shunt failure rates in spina bifida.

PubMed

Gonzalez, Dani O; Cooper, Jennifer N; McLeod, Daryl J

2017-12-11

Most patients with spina bifida require ventriculoperitoneal (VP) shunt placement. Some also require bladder augmentation, which may increase the risk of VP shunt malfunction and/or failure. The aim of this study was to assess whether bladder augmentation affects the rate of VP shunt failure in this population. Using the Pediatric Health Information System, we studied patients with spina bifida born between 1992 and 2014 who underwent VP shunt placement. Using conditional logistic regression, we compared age- and hospital-matched patients who did and did not undergo a bladder augmentation to determine their difference in rates of VP shunt failure. There were 4192 patients with spina bifida who underwent both surgical closure and VP shunt placement. Of these, 203 patients with bladder augmentation could be matched to 593 patients without bladder augmentation. VP shunt failure occurred within 2 years in 7.7% of patients, the majority of whom were in the group who underwent bladder augmentation (87%). After adjusting for confounders, undergoing bladder augmentation was independently associated with VP shunt failure (HR: 33.5, 95% CI: 13.15-85.44, p< 0.001). Bladder augmentation appears to be associated with VP shunt failure. Additional studies are necessary to better define this relationship and identify risk-reduction techniques.

Sexual function and erection capability among young men with spina bifida.

PubMed

Sandler, A D; Worley, G; Leroy, E C; Stanley, S D; Kalman, S

1996-09-01

In a study of sexual function and erection capability, 15 young men with spina bifida were interviewed, underwent physical examination, and completed two consecutive night recordings of penile tumescence and rigidity with the Rigi-Scan (Dacomed Inc.). Eleven reported erections with stimulation. Rigi-Scan data showed that two subjects (both with lesions at the sacral level) had normal numbers and durations of erections, that seven others had abnormally brief and infrequent nocturnal erections, and that six had none. Ten subjects had at least 'some' glans sensation on physical examination. Self-reported erection capability was related to motor level and glans sensation. The number of nocturnal erections was related to sensory level. The study suggests that lower motor and sensory levels are associated with greater potential sexual function in males with spina bifida.

Is autonomy related to the quality of performance of everyday activities in children with spina bifida?

PubMed

Peny-Dahlstrand, Marie; Krumlinde-Sundholm, Lena; Gosman-Hedström, Gunilla

2012-01-01

To investigate the relationship between the level of autonomy and the quality of performance of everyday activities in a population-based cohort of children with spina bifida and to study the agreement between the children's and the parents' ratings of autonomy. 50 dyads of children (aged 6-14) with spina bifida and their parents rated the children's level of autonomy with an adapted, Swedish version of the Autonomy Scale from the Arc's Self-Determination Scale. Each child's quality of performance of everyday activities was assessed with the Assessment of Motor and Process Skills (AMPS). The autonomy levels of the children with spina bifida were rated to be lowest in daily routines and highest in leisure activities. Binary logistic regression analyses revealed that age, motor skills and process skills were all significantly related to the autonomy level, but that process skills appeared to predominate in this respect. Concerning the perception of the autonomy level, little agreement was found between each child and his/her parent. It is important to understand and support the development of process skills as expressed in task performance in children with spina bifida and to pay attention to both the parent's and the child's opinion when setting goals and plans for interventions.

Cognitive changes after cerebrospinal fluid shunting in young adults with spina bifida and assumed arrested hydrocephalus

PubMed Central

Mataro, M.; Poca, M. A.; Sahuquillo, J.; Cuxart, A.; Iborra, J.; de la Calzada, M. D.; Junque, C.

2000-01-01

OBJECTIVES—To establish whether surgery can improve the neuropsychological functioning of young adult patients with spina bifida and apparent clinically arrested hydrocephalus showing abnormal intracranial pressure.
METHODS—Twenty three young adults with spina bifida and assumed arrested hydrocephalus (diagnosed as active or compensated by continuous intracranial pressure monitoring) underwent surgery. All patients received neuropsychological examination before surgery and 6 months later. Neuropsychological assessment included tests of verbal and visual memory, visuospatial functions, speed of mental processing, and frontal lobe functions.
RESULTS—Shunt placement in this subgroup of patients improves neuropsychological functioning, especially in verbal and visual memory and attention and cognitive flexibility.
CONCLUSIONS—Young adults with spina bifida and suspected non-functioning shunt or non-shunted ventriculomegaly should be carefully monitored to identify those who could benefit from shunting.

 PMID:10766893

Neurological bypass for sensory innervation of the penis in patients with spina bifida.

PubMed

Overgoor, Max L E; Kon, Moshe; Cohen-Kettenis, Peggy T; Strijbos, Saskia A M; de Boer, Niels; de Jong, Tom P V M

2006-09-01

Most male patients with spina bifida have normal sexual desires. During puberty they begin to realize that they can achieve erection and sexual intercourse but without any sensation in the penis. We hypothesized that restored sensation in the penis would greatly contribute to their quality of life and sexual health. In this prospective study we investigated the outcome of a new operative neurological bypass procedure in patients with spina bifida. In 3 patients who were 17, 18 and 21 years old with a spinal lesion at L5, L4 and L3-L4, respectively, the sensory ilioinguinal nerve (L1) was cut distal in the groin and joined by microneurorrhaphy to the divided ipsilateral dorsal nerve of the penis (S2-4) at the base of the penis. All patients underwent preoperative and postoperative neurological and psychological evaluations. By 15 months postoperatively all patients had achieved excellent sensation on the operated side of the glans penis. They were unequivocally positive about the results and the penis had become more integrated into the body image. In 2 patients masturbation became more meaningful and 1 became more sexually active with and without his partner. The newly designed neurological bypass procedure in patients with spina bifida resulted in excellent sensibility in the glans penis. The new sensation appeared to contribute to the quality of the patient sexuality and sexual functioning as well as to the feeling of being a more normal and complete individual who is more conscious of the penis. This new operation might become standard treatment in patients with spina bifida in the future.

Correlates of Self Esteem in Adolescents with Spina Bifida.

ERIC Educational Resources Information Center

Eckart, M. L.

The study examined correlates of self-esteem in 54 adolescents and young adults (ages 12-22) with spina bifida. Core issues identified were the relationships of global self-esteem and perceived competencies in specific areas, perceptions of control, and identification with the physically handicapped. Relationships of self-esteem to age, gender,…

Retrospective Assessment of Cost Savings From Prevention: Folic Acid Fortification and Spina Bifida in the U.S.

PubMed

Grosse, Scott D; Berry, Robert J; Mick Tilford, J; Kucik, James E; Waitzman, Norman J

2016-05-01

Although fortification of food with folic acid has been calculated to be cost saving in the U.S., updated estimates are needed. This analysis calculates new estimates from the societal perspective of net cost savings per year associated with mandatory folic acid fortification of enriched cereal grain products in the U.S. that was implemented during 1997-1998. Estimates of annual numbers of live-born spina bifida cases in 1995-1996 relative to 1999-2011 based on birth defects surveillance data were combined during 2015 with published estimates of the present value of lifetime direct costs updated in 2014 U.S. dollars for a live-born infant with spina bifida to estimate avoided direct costs and net cost savings. The fortification mandate is estimated to have reduced the annual number of U.S. live-born spina bifida cases by 767, with a lower-bound estimate of 614. The present value of mean direct lifetime cost per infant with spina bifida is estimated to be $791,900, or $577,000 excluding caregiving costs. Using a best estimate of numbers of avoided live-born spina bifida cases, fortification is estimated to reduce the present value of total direct costs for each year's birth cohort by $603 million more than the cost of fortification. A lower-bound estimate of cost savings using conservative assumptions, including the upper-bound estimate of fortification cost, is $299 million. The estimates of cost savings are larger than previously reported, even using conservative assumptions. The analysis can also inform assessments of folic acid fortification in other countries. Published by Elsevier Inc.

The impact of folic acid intake on the association among diabetes mellitus, obesity, and spina bifida.

PubMed

Parker, Samantha E; Yazdy, Mahsa M; Tinker, Sarah C; Mitchell, Allen A; Werler, Martha M

2013-09-01

The purpose of this study was to investigate the relationship between spina bifida and 2 established risk factors (pregestational diabetes mellitus and obesity) in both the presence and absence of the recommended daily folic acid intake in the periconceptional period. Cases of spina bifida (n = 1154) and control subjects (n = 9439) from the Slone Epidemiology Center Birth Defects Study (1976-2011) were included. Information on preexisting diabetes mellitus (collected 1976-2011) and obesity (collected 1993-2011), defined as a body mass index of ≥30 kg/m(2), was collected through interviews that were conducted within 6 months of delivery. Periconceptional folic acid intake was calculated with both dietary and supplement information. Mothers were classified as consuming more or less than 400 μg/day of folic acid; food folate was included at a 30% discount for its lower bioavailability. Logistic regression models that were adjusted for maternal age, race, education, and study site were used to calculate adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for the joint effects of low folic acid intake coupled with diabetes mellitus or obesity. Case mothers were more likely to have diabetes mellitus or be obese (0.7% and 19.0%, respectively) than control mothers (0.4% and 10.8%, respectively). The joint effect of diabetes mellitus and lower folic acid intake on spina bifida was larger (aOR, 3.95; 95% CI, 1.56-10.00) than that of diabetes mellitus and higher folic acid intake (aOR, 1.31; 95% CI, 0.17-10.30). Folic acid intake made little difference on the association between obesity and spina bifida. Our findings suggest that folic acid further attenuates, although does not eliminate, the risk of spina bifida that is associated with diabetes mellitus than the risk with obesity. Copyright © 2013 Mosby, Inc. All rights reserved.

Multidisciplinary study (CO2 flux, ERT, self-potential, permeability and structural surveys) in Fondi di Baia, Astroni and Agnano volcanoes: insights for the structural architecture of the Campi Flegrei caldera (southern Italy)

NASA Astrophysics Data System (ADS)

Isaia, Roberto; Carapezza, Maria Luisa; Conti, Eric; Giulia Di Giuseppe, Maria; Lucchetti, Carlo; Prinzi, Ernesto; Ranaldi, Massimo; Tarchini, Luca; Tramparulo, Francesco; Troiano, Antonio; Vitale, Stefano; Cascella, Enrico; Castello, Nicola; Cicatiello, Alessandro; Maiolino, Marco; Puzio, Domenico; Tazza, Lucia; Villani, Roberto

2017-04-01

Recent volcanism at Campi Flegrei caldera produced more than 70 eruptions in the last 15 ka formed different volcanic edifices. The vent distribution was related to the main volcano-tectonic structure active in the caldera along which also concentrated part of the present hydrothermal and fumarolic activity, such as in the Solfatara area. In order to define the role of major faults in the Campi Flegrei Caldera, we analyzed some volcanic craters (Fondi di Baia and Astroni) and the Agnano caldera, by means of different geochemical and geophysical technics including CO2 flux, electrical resistivity (ERT), self-potential and permeability surveys. We provided some ERT profiles and different maps of geochemical and geophysical features. Major fault planes were identified comparing ERT imaging with alignments of anomalies in maps. The results can improve the knowledge on the present state of these volcanoes actually not fully monitored though included in the area with high probability of future vent opening within the Campi Flegrei caldera.

[Orthopedic management of spina bifida].

PubMed

Biedermann, R

2014-07-01

Spina bifida is associated with congenital deformities, such as kyphosis, spinal malformations, teratological hip dislocations, clubfeet, vertical talus and also with acquired deformities due to muscle imbalance and impaired biomechanics. The degree of the acquired deformities and the mobility of the patient depend on the level of the spinal lesion. Neurological symptoms are mostly asymmetric and there is an inconsistent correlation between the anatomical level of the lesion and muscle function. Deficits of sensation are usually one to two levels lower than the motor level. An exact neurological diagnosis should not be made before the second or third year of life and an early prognosis about walking ability should be avoided. The level L3 and therefore function of the quadriceps is a functional milestone after which modified independent ambulation with the use of ankle foot orthoses (AFO) and crutches is possible. The basic principle is to support verticalization and gait even when loss of ambulation is later expected. It is also important to support and maintain sitting ability for high lesions, if necessary with correction of the spinal deformity. Findings in gait analysis have shifted the focus of treatment from radiological criteria to functional improvement, thus maintenance of the flexibility of the hip is the main goal of hip surgery. Reduction of the hip often leads to stiffness and has a high redislocation rate. Clubfoot deformities should be treated early and foot arthrodesis and stiffness have to be avoided. Another focus is the prevention of joint contracture by early prophylactic treatment. The purpose of management is to maximize the functional potential of the child. Subjective well-being, absence of pain, mobility and socialization are the main goals. This does not necessarily imply ambulation; nevertheless, verticalization and associated orthotic management is one major objective of the orthopedic management of spina bifida.

Motor evoked potentials and compound muscle action potentials as prognostic tools for neonates with spina bifida.

PubMed

Cuppen, Inge; Geerdink, Niels; Rotteveel, Jan J; Mullaart, Reinier; Roeleveld, Nel; Pasman, Jaco W

2013-03-01

MEPs and CMAPs as prognostic tools for spina bifida. The aim of this prospective study was to determine the prognostic value of neurophysiological investigations compared to clinical neurological examination in infants with spina bifida. Thirty-six neonates born with spina bifida between 2002 and 2007 were evaluated and followed for 2 years. Lumbar motor evoked potentials (MEPs) and compound muscle action potentials (CMAPs) were obtained at the median age of 2 days old before surgical closure of the spinal anomaly. MEPs were recorded from the quadriceps femoris, tibialis anterior, and gastrocnemius muscles and CMAPs from the latter two muscles. Areas under the curve and latencies of the MEPs and CMAPs were measured. Clinical neurological outcome at the age of 2 years was described using Muscle Function Classes (MFCs) and ambulation status. The areas under the curve of MEPs and CMAPs in the legs were associated with lower neonatal levels of motor and sensory impairment. Better muscle function class of the lower limbs at 2 years of age was associated with larger MEP and CMAP areas of the gastrocnemius and tibialis anterior muscles at neonatal age. MEPs and CMAPs of the gastrocnemius and tibialis anterior muscles are of prognostic value for clinical neurological outcome in neonates born with spina bifida. Copyright © 2012 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

Children with Spina Bifida: Why Do They Fail in School?

ERIC Educational Resources Information Center

Eisert, Debra C.; Shelburne, Kathryn

Thirty-eight children with spina bifida, a congenital defect involving the nervous system, were tested for verbal and performance ability and freedom from distractibility on the Wechsler Intelligence Scale for Children-Revised. Achievement on the Wide Range Achievement Test was also measured, and medical and socioeconomic information obtained.…

Biparietal/transverse abdominal diameter ratio ≤ 1: potential marker for open spina bifida at 11-13-week scan.

PubMed

Simon, E G; Arthuis, C J; Haddad, G; Bertrand, P; Perrotin, F

2015-03-01

In the first trimester of pregnancy, a biparietal diameter (BPD) below the 5(th) percentile is a simple marker that enables the prenatal detection of half of all cases of open spina bifida. We hypothesized that relating the BPD measurement to the transverse abdominal diameter (TAD) might be another simple and effective screening method. In this study we assessed the performance of using the BPD/TAD ratio during the first trimester of pregnancy in screening for open spina bifida. A total of 20,551 first-trimester ultrasound scans (11-13 weeks' gestation), performed between 2000 and 2013, were analyzed retrospectively; there were 26 cases of open spina bifida and 17,665 unaffected pregnancies with a crown-rump length of 45-84 mm and a record of both BPD and TAD measurements. The mean (± SD) BPD/TAD ratio was 1.00 ± 0.06 for fetuses with spina bifida and 1.13 ± 0.06 for those without (P < 0.0001). A BPD ≤ 5(th) percentile enabled the prenatal detection of 46.2% of spina bifida cases, while a BPD/TAD ratio of ≤ 1.00 detected 69.2%. If we considered cases in which either BPD was ≤ 5(th) percentile or BPD/TAD ratio was ≤ 1, we identified 76.9% of cases. In the latter case, the false-positive rate was 5.1%, while that for using a combination of both BPD ≤ 5th percentile and BPD/TAD ratio ≤ 1 was 0.6%, with a sensitivity of 38.5%. The positive predictive value of using a combination of BPD ≤ 5th percentile and BPD/TAD ratio ≤ 1 for detecting spina bifida was 8.5%. Between 11 and 13 weeks' gestation, relating BPD to TAD improves considerably the diagnostic performance of using BPD measurement alone in screening for open spina bifida. Screening using this marker is simple and applicable to a large population. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.

Effects of seated posture on erector spinae EMG activity during whole body vibration.

PubMed

Zimmermann, C L; Cook, T M; Goel, V K

1993-06-01

The purpose of this study was to evaluate the electromyographic (EMG) response of the erector spinae to whole body vibration in three different unsupported seated postures: neutral upright, forward lean, and posterior lean. Subjects were 11 healthy college-age men. EMG was collected using bipolar surface electrodes placed bilaterally over the erector spinae at the L4 level. A modified chair with attached accelerometer was affixed to an induction type vibrator. Subjects were vibrated vertically at 4.5 Hz and 6.21 m.s-2 RMS. Data were collected in each of the three postures for 30 s pre- and post-vibration and for 2 min during vibration. Mean EMG values were determined for each sampling period and compared using ANOVA. The mean value for anterior lean was significantly larger (p < 0.05) than that for posterior lean and neutral. EMG data analysed by triggered averaging showed a phase-dependent response to the vibratory cycle for the forward leaning and neutral upright postures. The results of this study indicate that the magnitude of the vibration synchronous response of the erector spinae musculature is dependent upon body posture. This response may be an important factor in the onset of muscular fatigue and the increased incidence of back disorders among individuals exposed to whole body vibration.

A comparison between placental and amniotic mesenchymal stem cells for transamniotic stem cell therapy (TRASCET) in experimental spina bifida.

PubMed

Feng, Christina; D Graham, Christopher; Connors, John Patrick; Brazzo, Joseph; Zurakowski, David; Fauza, Dario O

2016-06-01

We compared placental-derived and amniotic fluid-derived mesenchymal stem cells (pMSCs and afMSCs, respectively) in transamniotic stem cell therapy (TRASCET) for experimental spina bifida. Pregnant dams (n=29) exposed to retinoic acid for the induction of fetal spina bifida were divided into four groups. Three groups received volume-matched intraamniotic injections of either saline (n=38 fetuses) or a suspension of 2×10(6) cells/mL of syngeneic, labeled afMSCs (n=73) or pMSCs (n=115) on gestational day 17 (term=21-22days). Untreated fetuses served as controls. Animals were killed before term. Statistical comparisons were by Fisher's exact test (p<0.05). Survival was similar across treatment groups (p=0.08). In fetuses with isolated spina bifida (n=100), there were higher percentages of defect coverage (either partial or complete) in both afMSC and pMSC groups compared with saline and untreated groups (p<0.001-0.03 in pairwise comparisons). There were no differences in coverage rates between afMSC and pMSC groups (p=0.94) or between saline and untreated groups (p=0.98). Both pMSC and afMSC can induce comparable rates of coverage of experimental spina bifida after concentrated intraamniotic injection in the rodent model. This broadens the options for timing and cell source for TRASCET as a potential alternative in the prenatal management of spina bifida. Copyright © 2016 Elsevier Inc. All rights reserved.

Cytotoxicity of different extracts of arial parts of Ziziphus spina-christi on Hela and MDA-MB-468 tumor cells

PubMed Central

Jafarian, Abbas; Zolfaghari, Behzad; Shirani, Kobra

2014-01-01

Background: It has been shown that plants from the family Rhamnaceae possess anticancer activity. In this study, we sought to determine if Ziziphus spina-christi, a species from this family, has cytotoxic effect on cancer cell lines. Materials and Methods: Using maceration method, different extracts of leaves of Z. spina-christi were prepared. Hexane, chloroform, chloroform-methanol (9:1), methanol-water (7:1) methanol, butanol and water were used for extraction, after preliminary phytochemical analyses were done. The cytotoxic activity of the extracts against Hela and MDA-MB-468 tumor cells was evaluated by MTT assay. Briefly, cells were seeded in microplates and different concentrations of extracts were added. After incubation of cells for 72 h, their viability was evaluated by addition of tetrazolium salt solution. After 3 h medium was aspirated, dimethyl sulfoxide was added and absorbance was determined at 540 nm with an ELISA plate reader. Extracts were considered cytotoxic when more than 50% reduction on cell survival was observed. Results: Hexane, chloroform, chloroform-methanol, butanol, methanol-water and aqueous extracts of Z. spina-christi significantly and concentration-dependently reduced viability of Hela and MAD-MB-468 cells. In the both cell lines, chloroform-methanol extract of Z. spina-christi was more potent than the other extracts. Results: From the finding of this study it can be concluded that Z. spina-christi is a good candidate for further study for new cytotoxic agents. PMID:24627846

A reappraisal of the anatomy of the human lumbar erector spinae.

PubMed Central

Bogduk, N

1980-01-01

In the lumbar region the longissimus thoracis and iliocostalis lumborum are separated by the erector spinae aponeurosis and its ventral reflection--the lumbar intermuscular aponeurosis. Lumbar fibres of the longissimus arise from the ilium and the lumbar intermuscular aponeurosis and insert into the accessory processes and proximal ends of the transverse processes of the lumbar vertebrae. Lumbar fibres of iliocostalis insert into the costal elements of the first four lumbar vertebrae. The lumbar insertions of these muscles are homologous to their thoracic insertions. The lumbar intermuscular aponeurosis is homologous to the lumbar intermuscular septum in the dog, cat and monkey. The details of attachment of the lumbar fibres of the erector spinae and of the lumbar intermuscular aponeurosis should be taken into account in biomechanical analyses of the lumbar vertebral column. Images Fig. 1(cont.) Fig. 1 Fig. 3 Fig. 4 Fig. 5 PMID:7216917

Primary care providers and medical homes for individuals with spina bifida.

PubMed

Walker, William O

2008-01-01

The contributions of primary care providers to the successful care of children with spina bifida cannot be underestimated. Overcoming systemic barriers to their integration into a comprehensive care system is essential. By providing routine and disability specific care through the structure of a Medical Home, they are often the first line resource and support for individuals and their families. The Medical Home model encourages primary care providers to facilitate discussions on topics as varied as education and employment. Knowledge of specific medical issues unique to this population allows the primary care provider to complement the efforts of other specialty clinics and providers in often neglected areas such as sexual health, obesity and latex sensitization. As individuals with spina bifida live into adulthood, and access to traditional multidisciplinary care models evolves, these skills will take on increasing importance within the scope of providing comprehensive and coordinated care.

Predictors of parenting stress in mothers of children with spina bifida.

PubMed

Kanaheswari, Y; Razak, N N A; Chandran, V; Ong, L C

2011-03-01

Prospective cross-sectional multidimensional study using clinical assessment and standard measures. To determine the medical and social factors associated with parenting stress among mothers of children with spina bifida. Spina bifida clinics of two tertiary hospitals in urban Kuala Lumpur, Malaysia. A total of 81 mothers of children aged 1-18 years completed the Parenting Stress Index-Short Form (PSI/SF). Each child's adaptive skills were assessed using the Vineland Adaptive Behaviour Scales (VABS), Interview Edition. Medical and social data were obtained from direct interviews and case note reviews. Hierarchical multiple regression analysis was used to investigate factors that were determinants for high scores in the parental distress (PD), difficult child (DC) and parent-child dysfunctional interaction (P-CDI) subdomains of the PSI/SF. Results were expressed as beta coefficient (β) and 95% confidence intervals (95% CIs). Single-parent families (β 8.6, 95% CI 3.4-13.9) and the need for clean intermittent catheterization of bladder (β 3.5, 95% CI 0.7-6.2) were associated with high PD scores. Clean intermittent catheterization (β 3.0, 95% CI 0.5-5.5) was associated with higher DC scores. Lower composite VABS scores (β -0.08, 95% CI -0.02 to -0.15) and mother as the sole caregiver (β 2.6, 95% CI 0.15-4.96) was associated with higher P-CDI scores. The need for clean intermittent catheterization was the only medical factor associated with parenting stress in mothers of children with spina bifida. This was mediated by single parenthood, caregiver status and the child's adaptive skills.

CHKA and PCYT1A gene polymorphisms, choline intake and spina bifida risk in a California population

PubMed Central

Enaw, James O Ebot; Zhu, Huiping; Yang, Wei; Lu, Wei; Shaw, Gary M; Lammer, Edward J; Finnell, Richard H

2006-01-01

Background Neural tube defects (NTDs) are among the most common of all human congenital defects. Over the last two decades, accumulating evidence has made it clear that periconceptional intake of folic acid can significantly reduce the risk of NTD affected pregnancies. This beneficial effect may be related to the ability of folates to donate methyl groups for critical physiological reactions. Choline is an essential nutrient and it is also a methyl donor critical for the maintenance of cell membrane integrity and methyl metabolism. Perturbations in choline metabolism in vitro have been shown to induce NTDs in mouse embryos. Methods This study investigated whether single nucleotide polymorphisms (SNPs) in human choline kinase A (CHKA) gene and CTP:phosphocholine cytidylytransferase (PCYT1A) gene were risk factors for spina bifida. Fluorescence-based allelic discrimination analysis was performed for the two CHKA intronic SNPs hCV1562388 (rs7928739) and hCV1562393, and PCYT1A SNP rs939883 and rs3772109. The study population consisted of 103 infants with spina bifida and 338 non-malformed control infants who were born in selected California counties in the period 1989–1991. Results The CHKA SNP hCV1562388 genotypes with at least one C allele were associated with a reduced risk of spina bifida (odds ratio = 0.60, 95%CI = 0.38–0.94). The PCYT1A SNP rs939883 genotype AA was associated with a twofold increased risk of spina bifida (odds ratio = 1.89, 95% CI = 0.97–3.67). These gene-only effects were not substantially modified by analytic consideration to maternal periconceptional choline intake. Conclusion Our analyses showed genotype effects of CHKA and PCYT1A genes on spina bifida risk, but did not show evidence of gene-nutrient interactions. The underlying mechanisms are yet to be resolved. PMID:17184542

Mood-Stabilizing Anticonvulsants, Spina Bifida, and Folate Supplementation: Commentary.

PubMed

Patel, Neil; Viguera, Adele C; Baldessarini, Ross J

2018-02-01

High risks of neural tube defects and other teratogenic effects are associated with exposure in early pregnancy to some anticonvulsants, including in women with bipolar disorder. Based on a semistructured review of recent literature, we summarized findings pertaining to this topic. Valproate and carbamazepine are commonly used empirically (off-label) for putative long-term mood-stabilizing effects. Both anticonvulsants have high risks of teratogenic effects during pregnancy. Risks of neural tube defects (especially spina bifida) and other major malformations are especially great with valproate and can arise even before pregnancy is diagnosed. Standard supplementation of folic acid during pregnancy can reduce risk of spontaneous spina bifida, but not that associated with valproate or carbamazepine. In contrast, lamotrigine has regulatory approval for long-term use in bipolar disorder and appears not to have teratogenic effects in humans. Lack of protective effects against anticonvulsant-associated neural tube defects by folic acid supplements in anticipation of and during pregnancy is not widely recognized. This limitation and high risks of neural tube and other major teratogenic effects, especially of valproate, indicate the need for great caution in the use of valproate and carbamazepine to treat bipolar disorder in women of child-bearing age.

A Review of the Potential for Cardiometabolic Dysfunction in Youth with Spina Bifida and the Role for Physical Activity and Structured Exercise

PubMed Central

Short, Kevin R.; Frimberger, Dominic

2012-01-01

Children and adolescents who have decreased mobility due to spina bifida may be at increased risk for the components of metabolic syndrome, including abdominal obesity, insulin resistance, and dyslipidemia due to low physical activity. Like their nondisabled peers, adolescents with spina bifida that develop metabolic risk factors early in life have set the stage for adult disease. Exercise interventions can improve metabolic dysfunction in nondisabled youth, but the types of exercise programs that are most effective and the mechanisms involved are not known. This is especially true in adolescents with spina bifida, who have impaired mobility and physical function and with whom there have been few well-controlled studies. This paper highlights the current lack of knowledge about the role of physical activity and the need to develop exercise strategies targeting the reduction of cardiometabolic risk and improving quality of life in youth with spina bifida. PMID:22778758

A review of the potential for cardiometabolic dysfunction in youth with spina bifida and the role for physical activity and structured exercise.

PubMed

Short, Kevin R; Frimberger, Dominic

2012-01-01

Children and adolescents who have decreased mobility due to spina bifida may be at increased risk for the components of metabolic syndrome, including abdominal obesity, insulin resistance, and dyslipidemia due to low physical activity. Like their nondisabled peers, adolescents with spina bifida that develop metabolic risk factors early in life have set the stage for adult disease. Exercise interventions can improve metabolic dysfunction in nondisabled youth, but the types of exercise programs that are most effective and the mechanisms involved are not known. This is especially true in adolescents with spina bifida, who have impaired mobility and physical function and with whom there have been few well-controlled studies. This paper highlights the current lack of knowledge about the role of physical activity and the need to develop exercise strategies targeting the reduction of cardiometabolic risk and improving quality of life in youth with spina bifida.

Erector spinae plane block for radical mastectomy: A new indication?

PubMed

Veiga, M; Costa, D; Brazão, I

2018-02-01

The erector spinae plane block is a technique recently described by Forero et al. in September 2016. It has applications in the control of chronic pain with neuropathic component of the chest wall, and for pain control in thoracoscopic surgery. In this article, we describe the use of this technique as part of a multimodal analgesic approach in a 40-year-old woman, who underwent radical mastectomy due to breast cancer. By performing this block before anesthetic induction, we have achieved an opioid sparing effect, avoiding a possible immunomodulatory effect, although not yet proven in humans. During hospitalization, the patient reported no pain (0/10 in numeric scale), without resorting to rescue analgesia. The easy, fast and safe execution of erector spinae plane block makes it a promising technique in the context of surgical pain during radical mastectomy. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Handwriting Skills in Children with Spina Bifida: Assessment, Monitoring and Measurement.

ERIC Educational Resources Information Center

Hancock, Julie; Alston, Jean

1986-01-01

Case studies of three students with spina bifida (ages 8-11) illustrate an individualized six-week handwriting intervention program which stressed assessment, monitoring, and measurement of changes in writing performance. Appropriate changes in physical support (sitting position, writing surface, and choice of writing tool) are recommended. (JW)

The Management and Education of Children with Spina Bifida and Hydrocephalus.

ERIC Educational Resources Information Center

Andrews, Robert J.; Elkins, John

The report describes the population of children in Australia with spina bifida and/or hydrocephalus, notes their needs and characteristics, reviews their school placement and social circumstances, and considers future educational services for them. Initial chapters review the literature on medical, psychoeducational, and social-family aspects of…

Trunk isometric force production parameters during erector spinae muscle vibration at different frequencies

PubMed Central

2013-01-01

Background Vibration is known to alter proprioceptive afferents and create a tonic vibration reflex. The control of force and its variability are often considered determinants of motor performance and neuromuscular control. However, the effect of vibration on paraspinal muscle control and force production remains to be determined. Methods Twenty-one healthy adults were asked to perform isometric trunk flexion and extension torque at 60% of their maximal voluntary isometric contraction, under three different vibration conditions: no vibration, vibration frequencies of 30 Hz and 80 Hz. Eighteen isometric contractions were performed under each condition without any feedback. Mechanical vibrations were applied bilaterally over the lumbar erector spinae muscles while participants were in neutral standing position. Time to peak torque (TPT), variable error (VE) as well as constant error (CE) and absolute error (AE) in peak torque were calculated and compared between conditions. Results The main finding suggests that erector spinae muscle vibration significantly decreases the accuracy in a trunk extension isometric force reproduction task. There was no difference between both vibration frequencies with regard to force production parameters. Antagonist muscles do not seem to be directly affected by vibration stimulation when performing a trunk isometric task. Conclusions The results suggest that acute erector spinae muscle vibration interferes with torque generation sequence of the trunk by distorting proprioceptive information in healthy participants. PMID:23919578

38 CFR 3.814 - Monetary allowance under 38 U.S.C. chapter 18 for an individual suffering from spina bifida whose...

Code of Federal Regulations, 2013 CFR

2013-07-01

... is or was a Vietnam veteran or a veteran with covered service in Korea. 3.814 Section 3.814 Pensions... for an individual suffering from spina bifida whose biological father or mother is or was a Vietnam... an individual suffering from spina bifida whose biological mother or father is or was a Vietnam...

38 CFR 3.814 - Monetary allowance under 38 U.S.C. chapter 18 for an individual suffering from spina bifida whose...

Code of Federal Regulations, 2012 CFR

2012-07-01

... is or was a Vietnam veteran or a veteran with covered service in Korea. 3.814 Section 3.814 Pensions... for an individual suffering from spina bifida whose biological father or mother is or was a Vietnam... an individual suffering from spina bifida whose biological mother or father is or was a Vietnam...

38 CFR 3.814 - Monetary allowance under 38 U.S.C. chapter 18 for an individual suffering from spina bifida whose...

Code of Federal Regulations, 2014 CFR

2014-07-01

... is or was a Vietnam veteran or a veteran with covered service in Korea. 3.814 Section 3.814 Pensions... for an individual suffering from spina bifida whose biological father or mother is or was a Vietnam... an individual suffering from spina bifida whose biological mother or father is or was a Vietnam...

Effects of trajectory exercise using a laser pointer on electromyographic activities of the gluteus maximus and erector spinae during bridging exercises.

PubMed

Kim, Yu-Ri; Yoo, Won-Gyu

2016-01-01

[Purpose] The purpose of this study was to investigate activities of the hip extensors and erector spinae during bridging exercise by using instruments with a laser pointer on the pelvic belt. [Subjects] Twelve subjects (age, 23 to 33 years) with non-specific low back pain volunteered for this study. [Methods] Subjects performed bridging exercises with and without trajectory exercises by using a laser pointer fixed to a pelvic strap. The erector spinae, gluteus maximus and hamstring activities with and without trajectory exercises using a laser pointer were recorded on using electromyography. [Results] Compared to the without laser pointer group, the group that underwent bridging with trajectory exercises using a laser pointer had significantly higher gluteus maximus activity and significantly lower erector spinae activity. Significantly higher gluteus maximus/erector spinae activity ratios were observed when performing trajectory exercises using a laser pointer during bridging exercises. [Conclusion] This result suggests that trajectory exercises using a laser pointer during a bridging exercise would be effective for improving gluteus maximus activity.

MATHEMATICAL DEVELOPMENT IN SPINA BIFIDA

PubMed Central

English, Lianne H.; Barnes, Marcia A.; Taylor, Heather B.; Landry, Susan H.

2011-01-01

Spina bifida (SB) is a neural tube defect diagnosed before or at birth that is associated with a high incidence of math disability often without co-occurring difficulties in reading. SB provides an interesting population within which to examine the development of mathematical abilities and disability across the lifespan and in relation to the deficits in visual-spatial processing that are also associated with the disorder. An overview of math and its cognitive correlates in preschoolers, school-age children and adults with SB is presented including the findings from a longitudinal study linking early executive functions in infancy to the development of later preschool and school age math skills. These findings are discussed in relation to socio-historical perspectives on math education and implications for intervention and directions for further research are presented. PMID:19213013

Anomalous Development of Brain Structure and Function in Spina Bifida Myelomeningocele

ERIC Educational Resources Information Center

Juranek, Jenifer; Salman, Michael S.

2010-01-01

Spina bifida myelomeningocele (SBM) is a specific type of neural tube defect whereby the open neural tube at the level of the spinal cord alters brain development during early stages of gestation. Some structural anomalies are virtually unique to individuals with SBM, including a complex pattern of cerebellar dysplasia known as the Chiari II…

Air toxics and birth defects: a Bayesian hierarchical approach to evaluate multiple pollutants and spina bifida.

PubMed

Swartz, Michael D; Cai, Yi; Chan, Wenyaw; Symanski, Elaine; Mitchell, Laura E; Danysh, Heather E; Langlois, Peter H; Lupo, Philip J

2015-02-09

While there is evidence that maternal exposure to benzene is associated with spina bifida in offspring, to our knowledge there have been no assessments to evaluate the role of multiple hazardous air pollutants (HAPs) simultaneously on the risk of this relatively common birth defect. In the current study, we evaluated the association between maternal exposure to HAPs identified by the United States Environmental Protection Agency (U.S. EPA) and spina bifida in offspring using hierarchical Bayesian modeling that includes Stochastic Search Variable Selection (SSVS). The Texas Birth Defects Registry provided data on spina bifida cases delivered between 1999 and 2004. The control group was a random sample of unaffected live births, frequency matched to cases on year of birth. Census tract-level estimates of annual HAP levels were obtained from the U.S. EPA's 1999 Assessment System for Population Exposure Nationwide. Using the distribution among controls, exposure was categorized as high exposure (>95(th) percentile), medium exposure (5(th)-95(th) percentile), and low exposure (<5(th) percentile, reference). We used hierarchical Bayesian logistic regression models with SSVS to evaluate the association between HAPs and spina bifida by computing an odds ratio (OR) for each HAP using the posterior mean, and a 95% credible interval (CI) using the 2.5(th) and 97.5(th) quantiles of the posterior samples. Based on previous assessments, any pollutant with a Bayes factor greater than 1 was selected for inclusion in a final model. Twenty-five HAPs were selected in the final analysis to represent "bins" of highly correlated HAPs (ρ > 0.80). We identified two out of 25 HAPs with a Bayes factor greater than 1: quinoline (ORhigh = 2.06, 95% CI: 1.11-3.87, Bayes factor = 1.01) and trichloroethylene (ORmedium = 2.00, 95% CI: 1.14-3.61, Bayes factor = 3.79). Overall there is evidence that quinoline and trichloroethylene may be significant contributors to the risk of spina bifida

Measurements of the trapezius and erector spinae muscles using virtual touch imaging quantification ultrasound-Elastography: a cross section study.

PubMed

Heizelmann, Anne; Tasdemir, Sümeyra; Schmidberger, Julian; Gräter, Tilmann; Kratzer, Wolfgang; Grüner, Beate

2017-08-25

This study uses virtual touch imaging quantification (VTIQ) technology for the first time to conduct measurements of the trapezius and erector spinae muscles in a large study population. The significance of various influencing factors, such as age and sex, are also examined. The study population comprised 278 subjects. The Siemens Acuson S3000 and VTIQ technology were used for measurements of the trapezius and erector spinae muscles (Siemens Healthcare, Erlangen, Germany). The following mean values ± standard deviation were calculated: left trapezius: males 2.89 ± 0.38 m/s, females 2.71 ± 0.37 m/s; right trapezius: males 2.84 ± 0.41 m/s, females 2.70 ± 0.38 m/s; left erector spinae: males 2.97 ± 0.50 m/s, females 2.81 ± 0.57 m/s; right erector spinae: males 3.00 ± 0.52 m/s, females 2.77 ± 0.59 m/s. A significant difference between male and female subjects was demonstrated both for the shear wave velocities of the trapezius and erector spinae as well as for the thickness of the trapezius muscle (p < 0.05). There was also a significant difference in muscle elasticity between subjects over 60 years of age and those under 60 (p < 0.05). Furthermore, the results indicate that regular physical activity has an effect on muscle elasticity. Our results demonstrate significantly different results between male and female subjects and between under- and over-sixty-year-old subjects. This means that sex-related and age-adapted considerations are obviously needed for further studies.

Spondylolisthesis in an Etruscan woman from Spina (Ferrara, Italy): an iron age case report.

PubMed

Manzon, Vanessa Samantha; Onisto, Nicoletta; Gualdi-Russo, Emanuela

2014-06-01

Spondylolisthesis consists of the slippage of a vertebra in relation to the one beneath. It is caused by separation of the neural arch from the vertebral body (spondylolysis), and predominantly occurs at the isthmus (pars interarticularis). Originally thought to be a congenital anomaly, its strict correlation with certain activities that seem to exert stress on lower spine was later demonstrated. This paper describes a case of progression of spondylolysis to spondylolisthesis found on an adult female skeleton from the Etruscan necropolis of Spina (Ferrara, Italy). The case in question was identified among 209 skeletons exhumed at Spina. As spondylolisthesis is strictly connected with activities that exert stress on lower spine, the evidence suggests that this woman was engaged in stressful physical activity, perhaps related to the specific trade function of the site.

Medical adherence in young adolescents with spina bifida: longitudinal associations with family functioning.

PubMed

Stepansky, Mona A; Roache, Caitlin R; Holmbeck, Grayson N; Schultz, Karen

2010-03-01

The purpose of this study was 2-fold: (1) to explore the transfer of responsibility of medical tasks from parent to child during the transition to adolescence, and (2) to examine the associations between family functioning and medical adherence in youth with spina bifida. Seventy families of children with spina bifida participated in this study. Data were collected during family interaction sessions by using questionnaires completed by mothers, fathers, youth, teachers and health professionals. Findings suggest that responsibility for medical regimens transfers gradually from parent to child over time. Additionally, family conflict and cohesion were correlated with medical adherence. Finally, family conflict over medical issues was related to a decrease in medical adherence over time. Results suggest that as youth take more responsibility over their medical regimens, family conflict regarding medical issues becomes a contributor to their adherence behaviors. Interventions that target family conflict may facilitate adherence behaviors.

Spina bifida and cleft lip among newborns of Norwegian women with epilepsy: changes related to the use of anticonvulsants.

PubMed Central

King, P B; Lie, R T; Irgens, L M

1996-01-01

OBJECTIVES: This study examined the connection between the use of anticonvulsants for epilepsy during or before pregnancy and the risk of spina bifida and cleft lip in newborns. METHODS: Among mothers registered from 1967 to 1992 by the Medical Birth Registry of Norway, 7588 who had epilepsy were identified and their newborns' prevalence of spina bifida and cleft lip examined. RESULTS: The odds ratio of spina bifida in children of mothers with epilepsy compared with other children increased from 1.5 in 1967 through 1980 (95% confidence interval [CI] = 0.3, 4.5) to 4.4 in 1981 through 1992 (95% CI = 2.0, 8.5). The odds ratio of cleft lip, however, decreased from 3.0 before 1981 (95% CI = 1.6, 5.1) to 1.1 after 1981 (95% CI = 0.4, 2.3). CONCLUSIONS: This shift toward more serious birth defects is consistent with the different teratogenic effects of newer and older anticonvulsants. PMID:8876519

Epidemiologic and Genetic Aspects of Spina Bifida and Other Neural Tube Defects

ERIC Educational Resources Information Center

Au, Kit Sing; Ashley-Koch, Allison; Northrup, Hope

2010-01-01

The worldwide incidence of neural tube defects (NTDs) ranges from 1.0 to 10.0 per 1,000 births with almost equal frequencies between two major categories: anencephaly and spina bifida (SB). Epidemiological studies have provided valuable insight for (a) researchers to identify nongenetic and genetic factors contributing to etiology, (b) public…

Transition to Adult Health Care for Adolescents with Spina Bifida: Research Issues

ERIC Educational Resources Information Center

Sawyer, Susan M.; Macnee, Sarah

2010-01-01

The increasing survival of children and young people with congenital disabilities such as spina bifida (SB) provides a challenge to health care systems globally about how best to respond to the multitude of health, developmental, and psychosocial needs of those affected by this complex disorder across the lifespan, not just in childhood and…

Posterior brain in fetuses with open spina bifida at 11 to 13 weeks.

PubMed

Lachmann, Robert; Chaoui, Rabih; Moratalla, Jose; Picciarelli, Gemma; Nicolaides, Kypros H

2011-01-01

To measure the changes in the posterior fossa in first-trimester fetuses with open spina bifida (OSB). The brain stem diameter and brain stem to occipital bone (BSOB) diameter were measured in stored images of the mid-sagittal view of the fetal face at 11(+0) to 13(+6) weeks from 30 fetuses with OSB and 1000 normal controls. In the control group, the brain stem and BSOB diameter increased significantly with crown-rump length (CRL) and the brain stem to BSOB ratio decreased. In the spina bifida group, the brain stem diameter was above the 95th percentile of the control group in 29 (96.7%) cases, the BSOB diameter was below the 5th percentile in 26 (86.7%) and the brain stem to BSOB ratio was above the 95th percentile in all cases. At 11 to 13 weeks the majority of fetuses with OSB have measurable abnormalities in the posterior brain.

Accessibility of mHealth Self-Care Apps for Individuals with Spina Bifida

PubMed Central

Yu, Daihua X.; Parmanto, Bambang; Dicianno, Brad E.; Pramana, Gede

2015-01-01

As the smartphone becomes ubiquitous, mobile health is becoming a viable technology to empower individuals to engage in preventive self-care. An innovative mobile health system called iMHere (Internet Mobile Health and Rehabilitation) has been developed at the University of Pittsburgh to support self-care and adherence to self-care regimens for individuals with spina bifida and other complex conditions who are vulnerable to secondary complications. The goal of this study was to explore the accessibility of iMHere apps for individuals with spina bifida. Six participants were asked to perform tasks in a lab environment. Though all of the participants were satisfied with the iMHere apps and would use them again in the future, their needs and preferences to access and use iMHere apps differed. Personalization that provides the ability for a participant to modify the appearance of content, such as the size of the icons and the color of text, could be an ideal solution to address potential issues and barriers to accessibility. The importance of personalization—and potential strategies—for accessibility are discussed. PMID:26755902

Design and Methodological Considerations of the Centers for Disease Control and Prevention Urologic and Renal Protocol for the Newborn and Young Child with Spina Bifida

PubMed Central

Routh, Jonathan C.; Cheng, Earl Y.; Austin, J. Christopher; Baum, Michelle A.; Gargollo, Patricio C.; Grady, Richard W.; Herron, Adrienne R.; Kim, Steven S.; King, Shelly J.; Koh, Chester J.; Paramsothy, Pangaja; Raman, Lisa; Schechter, Michael S.; Smith, Kathryn A.; Tanaka, Stacy T.; Thibadeau, Judy K.; Walker, William O.; Wallis, M. Chad; Wiener, John S.; Joseph, David B.

2016-01-01

Purpose Care of children with spina bifida has significantly advanced in the last half century, resulting in gains in longevity and quality of life for affected children and caregivers. Bladder dysfunction is the norm in patients with spina bifida and may result in infection, renal scarring and chronic kidney disease. However, the optimal urological management for spina bifida related bladder dysfunction is unknown. Materials and Methods In 2012 the Centers for Disease Control and Prevention convened a working group composed of pediatric urologists, nephrologists, epidemiologists, methodologists, community advocates and Centers for Disease Control and Prevention personnel to develop a protocol to optimize urological care of children with spina bifida from the newborn period through age 5 years. Results An iterative quality improvement protocol was selected. In this model participating institutions agree to prospectively treat all newborns with spina bifida using a single consensus based protocol. During the 5-year study period outcomes will be routinely assessed and the protocol adjusted as needed to optimize patient and process outcomes. Primary study outcomes include urinary tract infections, renal scarring, renal function and bladder characteristics. The protocol specifies the timing and use of testing (eg ultrasonography, urodynamics) and interventions (eg intermittent catheterization, prophylactic antibiotics, antimuscarinic medications). Starting in 2014 the Centers for Disease Control and Prevention began funding 9 study sites to implement and evaluate the protocol. Conclusions The Centers for Disease Control and Prevention Urologic and Renal Protocol for the Newborn and Young Child with Spina Bifida began accruing patients in 2015. Assessment in the first 5 years will focus on urinary tract infections, renal function, renal scarring and clinical process improvements. PMID:27475969

Determination of the motor unit behavior of lumbar erector spinae muscles through surface EMG decomposition technology in healthy female subjects.

PubMed

Silva, Mariana Felipe; Dias, Josilainne Marcelino; Pereira, Ligia Maxwell; Mazuquin, Bruno Fles; Lindley, Steven; Richards, Jim; Cardoso, Jefferson Rosa

2017-01-01

The aims of this study were to determine the motor unit behavior of the erector spinae muscles and to assess whether differences exist between the dominant/nondominant sides of the back muscles. Nine healthy women, aged 21.7 years (SD = 0.7), performed a back extension test. Surface electromyographic decomposition data were collected from both sides of the erector spinae and decomposed into individual motor unit action potential trains. The mean firing rate for each motor unit was calculated, and a regression analysis was performed against the corresponding recruitment thresholds. The mean firing rate ranged from 15.9 to 23.9 pps and 15.8 to 20.6 pps on the dominant and nondominant sides, respectively. However, the early motor unit potentials of the nondominant lumbar erector spinae muscles were recruited at a lower firing rate. This technique may further our understanding of individuals with back pain and other underlying neuromuscular diseases. Muscle Nerve 55: 28-34, 2017. © 2016 Wiley Periodicals, Inc.

Prevalence of and risk factors for latex sensitization in patients with spina bifida.

PubMed

Bernardini, R; Novembre, E; Lombardi, E; Mezzetti, P; Cianferoni, A; Danti, A D; Mercurella, A; Vierucci, A

1998-11-01

We determined the prevalence of and risk factors for latex sensitization in patients with spina bifida. A total of 59 consecutive subjects 2 to 40 years old with spina bifida answered a questionnaire, and underwent a latex skin prick test and determination of serum IgE specific for latex by RAST CAP radioimmunoassay. We also noted the relationships of total serum IgE skin prick tests to common air and food allergens. In addition, skin prick plus prick tests were also done with fresh foods, including kiwi, pear, orange, almond, pineapple, apple, tomato and banana. Latex sensitization was present in 15 patients (25%) according to the presence of IgE specific to latex, as detected by a skin prick test in 9 and/or RAST CAP in 13. Five latex sensitized patients (33.3%) had clinical manifestations, such as urticaria, conjuctivitis, angioedema, rhinitis and bronchial asthma, while using a latex glove and inflating a latex balloon. Atopy was present in 21 patients (35.6%). In 14 patients (23%) 1 or more skin tests were positive for fresh foods using a prick plus prick technique. Tomato, kiwi, and pear were the most common skin test positive foods. Univariate analysis revealed that a history of 5 or more operations, atopy and positive prick plus prick tests results for pear and kiwi were significantly associated with latex sensitization. Multivariate analysis demonstrated that only atopy and a history of 5 or more operations were significantly and independently associated with latex sensitization. A fourth of the patients with spina bifida were sensitized to latex. Atopy and an elevated number of operations were significant and independent predictors of latex sensitization in these cases.

Global Birth Prevalence of Spina Bifida by Folic Acid Fortification Status: A Systematic Review and Meta-Analysis.

PubMed

Atta, Callie A M; Fiest, Kirsten M; Frolkis, Alexandra D; Jette, Nathalie; Pringsheim, Tamara; St Germaine-Smith, Christine; Rajapakse, Thilinie; Kaplan, Gilaad G; Metcalfe, Amy

2016-01-01

Birth defects remain a significant source of worldwide morbidity and mortality. Strong scientific evidence shows that folic acid fortification of a region's food supply leads to a decrease in spina bifida (a birth defect of the spine). Still, many countries around the world have yet to approve mandatory fortification through government legislation. We sought to perform a systematic review and meta-analysis of period prevalence of spina bifida by folic acid fortification status, geographic region, and study population. An expert research librarian used terms related to neural tube defects and epidemiology from primary research from 1985 to 2010 to search in EMBASE and MEDLINE. We searched the reference lists of included articles and key review articles identified by experts. Inclusion criteria included studies in English or French reporting on prevalence published between January 1985 and December 2010 that (1) were primary research, (2) were population-based, and (3) reported a point or period prevalence estimate of spina bifida (i.e., prevalence estimate with confidence intervals or case numerator and population denominator). Two independent reviewers screened titles and abstracts for eligible articles, then 2 authors screened full texts in duplicate for final inclusion. Disagreements were resolved through consensus or a third party. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, abstracting data related to case ascertainment, study population, folic acid fortification status, geographic region, and prevalence estimate independently and in duplicate. We extracted overall data and any subgroups reported by age, gender, time period, or type of spina bifida. We classified each period prevalence estimate as "mandatory" or "voluntary" folic acid fortification according to each country's folic acid fortification status at the time data were collected (as determined by a well-recognized fortification monitoring body, Food

Design and Methodological Considerations of the Centers for Disease Control and Prevention Urologic and Renal Protocol for the Newborn and Young Child with Spina Bifida.

PubMed

Routh, Jonathan C; Cheng, Earl Y; Austin, J Christopher; Baum, Michelle A; Gargollo, Patricio C; Grady, Richard W; Herron, Adrienne R; Kim, Steven S; King, Shelly J; Koh, Chester J; Paramsothy, Pangaja; Raman, Lisa; Schechter, Michael S; Smith, Kathryn A; Tanaka, Stacy T; Thibadeau, Judy K; Walker, William O; Wallis, M Chad; Wiener, John S; Joseph, David B

2016-12-01

Care of children with spina bifida has significantly advanced in the last half century, resulting in gains in longevity and quality of life for affected children and caregivers. Bladder dysfunction is the norm in patients with spina bifida and may result in infection, renal scarring and chronic kidney disease. However, the optimal urological management for spina bifida related bladder dysfunction is unknown. In 2012 the Centers for Disease Control and Prevention convened a working group composed of pediatric urologists, nephrologists, epidemiologists, methodologists, community advocates and Centers for Disease Control and Prevention personnel to develop a protocol to optimize urological care of children with spina bifida from the newborn period through age 5 years. An iterative quality improvement protocol was selected. In this model participating institutions agree to prospectively treat all newborns with spina bifida using a single consensus based protocol. During the 5-year study period outcomes will be routinely assessed and the protocol adjusted as needed to optimize patient and process outcomes. Primary study outcomes include urinary tract infections, renal scarring, renal function and bladder characteristics. The protocol specifies the timing and use of testing (eg ultrasonography, urodynamics) and interventions (eg intermittent catheterization, prophylactic antibiotics, antimuscarinic medications). Starting in 2014 the Centers for Disease Control and Prevention began funding 9 study sites to implement and evaluate the protocol. The Centers for Disease Control and Prevention Urologic and Renal Protocol for the Newborn and Young Child with Spina Bifida began accruing patients in 2015. Assessment in the first 5 years will focus on urinary tract infections, renal function, renal scarring and clinical process improvements. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Factors Associated With Pressure Ulcers in Individuals With Spina Bifida

PubMed Central

Kim, Sunkyung; Ward, Elisabeth; Dicianno, Brad E.; Clayton, Gerald H.; Sawin, Kathleen J.; Beierwaltes, Patricia; Thibadeau, Judy

2015-01-01

Objective To describe factors associated with pressure ulcers in individuals with spina bifida (SB) enrolled in the National Spina Bifida Patient Registry (NSBPR). Design Unbalanced longitudinal multicenter cohort study. Setting Nineteen SB clinics. Participants Individuals with SB (N=3153) enrolled in 19 clinic sites that participate in the NSBPR. Interventions Not applicable. Main Outcome Measures Pressure ulcer status (yes/no) at the annual visit between 2009 and 2012. Results Of 3153 total participants, 19% (n=603) reported ulcers at their most recent annual clinic visit. Seven factors–level of lesion, wheelchair use, urinary incontinence, shunt presence, above the knee orthopedic surgery, recent surgery, and male sex–were significantly associated with the presence of pressure ulcers. Of these factors, level of lesion, urinary incontinence, recent surgery, and male sex were included in the final logistic regression model. The 3 adjusting variables–SB type, SB clinic, and age group–were significant in all analyses (all P<.001). Conclusions By adjusting for SB type, SB clinic, and age group, we found that 7 factors–level of lesion, wheelchair use, urinary incontinence, shunt presence, above the knee orthopedic surgery, recent surgery, and male sex–were associated with pressure ulcers. Identifying key factors associated with the onset of pressure ulcers can be incorporated into clinical practice in ways that prevent and enhance treatment of pressure ulcers in the population with SB. PMID:25796136

The Arnold-Chiari Malformation and Its Implications for Individuals with Spina Bifida and Hydrocephalus.

ERIC Educational Resources Information Center

Mittler, Joel E.

1986-01-01

The Arnold-Chiari malformation is present in most infants born with myelomeningocele (a form of spina bifida) and hydrocephalus. The syndrome is responsible for structural abnormalities in the brain, and peripheral nervous system. Etiology, symptoms, impact on central nervous system structures, surgical treatment, and implications for education…

Parental stress and support of parents of children with spina bifida in Uganda.

PubMed

Bannink, Femke; Idro, Richard; van Hove, Geert

2016-01-01

Children with disabilities in Sub-Saharan Africa depend for a large part of their functioning on their parent or caregiver. This study explores parental stress and support of parents of children with spina bifida in Uganda. The study aimed to explore perceived stress and support of parents of children with spina bifida living in Uganda and the factors that influence them. A total of 134 parents were interviewed. Focus group discussions were held with four parent support groups in four different regions within the country. The Vineland Adaptive Behaviour Scales, Daily Functioning Subscales and Parental Stress Index Short Form (PSI/SF) were administered to measure the child's daily functioning level and parental stress levels. Parental stress was high in our study population with over half of the parents having a > 90% percentile score on the PSI/SF. Stress outcomes were related to the ability to walk (Spearman's correlation coefficient [ ρ ] = -0.245), continence ( ρ = -0.182), use of clean intermittent catheterisation (ρ = -0.181) and bowel management ( ρ = -0.213), receiving rehabilitative care ( ρ = -0.211), household income ( ρ = -0.178), geographical region ( ρ = -0.203) and having support from another parent in taking care of the child ( ρ = -0.234). Linear regression showed parental stress was mostly explained by the child's inability to walk ( β = -0.248), practicing bowel management ( β = -0.468) and having another adult to provide support in caring for the child ( β = -0.228). Parents in northern Uganda had significantly higher scores compared to parents in other regions (Parental Distress, F = 5.467*; Parent-Child Dysfunctional Interaction, F = 8.815**; Difficult Child score, F = 10.489**). Parents of children with spina bifida experience high levels of stress. To reduce this stress, rehabilitation services should focus on improving mobility. Advocacy to reduce stigmatisation and peer support networks also need to be strengthened and developed.

The Influence of Juggling on Mental Rotation Performance in Children with Spina Bifida

ERIC Educational Resources Information Center

Lehmann, Jennifer; Jansen, Petra

2012-01-01

This study examined the influence of juggling training on mental rotation ability in children with spina bifida. Children between the ages of 8 and 12 solved a chronometric mental rotation test. Half of the children received juggling training (EG) over an 8 week time period; the other half did not receive training (CG). Afterwards, all…

Inferential Ability in Children with Cerebral Palsy, Spina Bifida and Pragmatic Language Impairment

ERIC Educational Resources Information Center

Holck, Pernille; Sandberg, Annika Dahlgren; Nettelbladt, Ulrika

2010-01-01

The aim of the study was to investigate and compare the ability to make inferences in three groups of children ranging from 5;2 to 10;9 years: 10 children with cerebral palsy (CP), 10 children with spina bifida and hydrocephalus (SBH) and 10 children with pragmatic language impairment (PLI). The relationship between inferential and literal…

Surrogate Pregnancy After Prenatal Diagnosis of Spina Bifida.

PubMed

Mazur, Lynnette J; Kisthardt, Mary Kay; Kim, Helen H; Rosas, Laura M; Lantos, John D

2017-02-01

Some pregnancies today involve infertile individuals or couples who contract with a fertile woman to carry a pregnancy for them. The woman who carries the pregnancy is referred to as a "gestational carrier." The use of such arrangements is increasing. Most of the time, these arrangements play out as planned; sometimes, however, problems arise. This article discusses a case in which a fetal diagnosis of spina bifida led the infertile couple to request that the gestational carrier terminate the pregnancy, and the gestational carrier did not wish to do so. Experts in the medical and legal issues surrounding surrogacy discuss the considerations that should go into resolving such a conflict. Copyright © 2017 by the American Academy of Pediatrics.

The Language of Children with Spina Bifida and Hydrocephalus: Meeting Task Demands and Mastering Syntax.

ERIC Educational Resources Information Center

Byrne, Karen; And Others

1990-01-01

Linguistic performance of 7 children (mean age=68 months) with spina bifida, hydrocephalus, and average intelligence was evaluated. Subjects dealt with the semantic-pragmatic requirements of linguistically posed problems in an age-appropriate manner. Performance declined as task demands increased but no more than performance of nondisabled…

Relationship Between Erectores Spinae Voltage and Back-Lift Strength for Isometric, Concentric, and Eccentric Contractions

ERIC Educational Resources Information Center

Ashton, T. Edwin J.; Singh, Mohan

1975-01-01

This study determined the maximal mean values for concentric and eccentric back-lift strength as well as isometric, and examined and compared the relationships between the mean peak voltage of the erectores spinae muscle(s) and maximal force exerted for the three types of muscle contractions. (RC)

The effect of spinal cord level on sexual function in the spina bifida population.

PubMed

Lee, N G; Andrews, E; Rosoklija, I; Logvinenko, T; Johnson, E K; Oates, R D; Estrada, C R

2015-06-01

Sexual dysfunction and infertility are prevalent in the spina bifida (SB) population; however, the mechanism of how they affect a person with spina bifida is poorly understood. Additionally, the management of children with spina bifida becomes more difficult as they exit from pediatric institutes. The present study sought to evaluate sexual health (using validated questionnaires) and fertility in adults with spina bifida and to correlate spinal cord level and ambulatory status with degree of sexual function. After institutional board review approval, 199 adult patients with SB, aged 18 and older and who were followed in one pediatric institution, were identified. Patients who were non-English speaking, cognitively and/or developmentally delayed, or unable to be contacted were excluded. Surveys regarding demographics, sexual health and infertility were mailed to the patients and administered in the clinic with the option to opt-out of the survey. Survey questions regarding sexual health were constructed using validated questionnaires: Female Sexual Function Index (FSFI) for females, and International Index of Erectile Function (IIEF) and Sexual Health Inventory for Men (SHIM) for males. Sexual dysfunction scores were correlated to the patients' spinal level and ambulatory status. Of the 121 eligible patients, 45 replied, with a response rate of 39%. For females, using a cut-off value of 26.5 for FSFI scoring, 25 out of 28 (89%) had sexual dysfunction. No association was seen between spinal level or ambulatory status and overall FSFI, satisfaction, or desire scores. For males, 10 out of 17 (59%) had severe erectile dysfunction (ED), and one out of 17 (6%) had no ED. No association was seen between ambulatory status and sexual function scores for the males. However, SHIM, satisfaction, and ED scores were higher in males with lower spinal lesions. People with spina bifida of both genders tended to have more severe dysfunction compared to those with sexual dysfunction

Is continence status associated with quality of life in young children with spina bifida?

PubMed

Freeman, Kurt A; Smith, Kathryn; Adams, Elizabeth; Mizokawa, Stacey; Neville-Jan, Ann

2013-01-01

To evaluate the relationship between child- and parent-reported quality of life (QOL) and bowel and bladder continence among young children with spina bifida (SB). 104 children ages 5-12 years and one of their parents/guardians completed the Pediatric Quality of Life Inventory - Generic Form (PedsQL; parent and child) and the Quality of Life in Spina Bifida Questionnaire (QOLSBQ, parent only). Data on continence, child age, and condition-specific variables were obtained by chart review. Parent and child QOL scores (on all measures of QOL) were positively correlated; parents rated child QOL lower than children's self report. QOL scores did not differ based on continence status. Total PedsQL scores were associated with age and mobility based on child report and with mobility based on parent report. QOL may not be affected by continence status among young children with SB, though demographic (i.e., age) and condition-specific (i.e., functional mobility status) variables appear relevant. Additional research is needed to further evaluate condition-specific variables, other protective variables, and possible measurement issues that influence QOL in young children with SB.

Arithmetic Processing in Children with Spina Bifida: Calculation Accuracy, Strategy Use, and Fact Retrieval Fluency

ERIC Educational Resources Information Center

Barnes, Marcia A.; Wilkinson, Margaret; Khemani, Ekta; Boudesquie, Amy; Dennis, Maureen; Fletcher, Jack M.

2006-01-01

Three studies compared 98 children with spina bifida myelomeningocele (SBM)--a disorder associated with high rates of math disability and spatial deficits--to 94 typically developing children on multidigit subtraction and cognitive addition tasks. Children with SBM were classified into those with reading decoding and math disability, only math…

Screening of polymorphisms for MTHFR and DHFR genes in spina bifida children and their mothers

NASA Astrophysics Data System (ADS)

Husna, M. Z.; Endom, I.; Ibrahim, S.; Selvi, N. Amaramalar; Fakhrurazi, H.; Htwe, R. Ohnmar; Kanehaswari, Y.; Halim, A. R. Abdul; Wong, S. W.; Subashini, K.; Syahira, O. Nur; Aishah, S.

2013-11-01

Mechanism underlying the beneficial effect of folic acid supplementation in reducing the risk of neural tube defect is still not well understood. Current evidences show the involvement of folic acid metabolic gene's polymorphism as contributing factors that regulate this pathway. Therefore, the objective of this research was to determine the presence of C677T polymorphism for methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR-19 bp deletion) genes between mother-children pairs of case and control. With the approval of UKMMC ethic committee, genomic DNA was extracted from one hundred and forty consented bloods. Polymerase chain reaction (PCR), PCR-RFLP (Restriction Fragment Length Polymorphism) and sequencing were employed to verify each nucleotide change. Our result shows that mutant MTHFR and DHFR alleles are present in all Malaysian sub-ethnic groups, case and control. Even though mutant MTHFR are found to be slightly higher in the case groups, 75% of the affected child is a non carrier for this allele and 62.5% of the mothers with an affected child are genotypically normal. For DHFR, almost all (87.5-100%) investigated samples are a carrier or having a double DHFR deletion be it a case or control pairs. However, strong maternal inheritance shown by the deleted allele might be due to a cascade effect of lacks of folate consumption or maternal uniparental disomy. In conclusion, the use of MTHFR and DHFR as markers in determining the risk of having spina bifida baby is uninformative and plays a small indirect role as the genetic causes of spina bifida. Therefore, spina bifida remains etiologically unknown polygenic and quantitative developmental trait whereby the searches for positive genetic marker need to be continued.

Arm cranking versus wheelchair propulsion for testing aerobic fitness in children with spina bifida who are wheelchair dependent.

PubMed

Bloemen, Manon A T; de Groot, Janke F; Backx, Frank J G; Westerveld, Rosalyne A; Takken, Tim

2015-05-01

To determine the best test performance and feasibility using a Graded Arm Cranking Test vs a Graded Wheelchair Propulsion Test in young people with spina bifida who use a wheelchair, and to determine the reliability of the best test. Validity and reliability study. Young people with spina bifida who use a wheelchair. Physiological responses were measured during a Graded Arm Cranking Test and a Graded Wheelchair Propulsion Test using a heart rate monitor and calibrated mobile gas analysis system (Cortex Metamax). For validity, peak oxygen uptake (VO2peak) and peak heart rate (HRpeak) were compared using paired t-tests. For reliability, the intra-class correlation coefficients, standard error of measurement, and standard detectable change were calculated. VO2peak and HRpeak were higher during wheelchair propulsion compared with arm cranking (23.1 vs 19.5 ml/kg/min, p = 0.11; 165 vs 150 beats/min, p < 0.05). Reliability of wheelchair propulsion showed high intra-class correlation coefficients (ICCs) for both VO2peak (ICC = 0.93) and HRpeak (ICC = 0.90). This pilot study shows higher HRpeak and a tendency to higher VO2peak in young people with spina bifida who are using a wheelchair when tested during wheelchair propulsion compared with arm cranking. Wheelchair propulsion showed good reliability. We recommend performing a wheelchair propulsion test for aerobic fitness testing in this population.

Parental stress and support of parents of children with spina bifida in Uganda

PubMed Central

Idro, Richard; van Hove, Geert

2016-01-01

Background Children with disabilities in Sub-Saharan Africa depend for a large part of their functioning on their parent or caregiver. This study explores parental stress and support of parents of children with spina bifida in Uganda. Objectives The study aimed to explore perceived stress and support of parents of children with spina bifida living in Uganda and the factors that influence them. Methods A total of 134 parents were interviewed. Focus group discussions were held with four parent support groups in four different regions within the country. The Vineland Adaptive Behaviour Scales, Daily Functioning Subscales and Parental Stress Index Short Form (PSI/SF) were administered to measure the child’s daily functioning level and parental stress levels. Results Parental stress was high in our study population with over half of the parents having a > 90% percentile score on the PSI/SF. Stress outcomes were related to the ability to walk (Spearman’s correlation coefficient [ρ] = −0.245), continence (ρ = −0.182), use of clean intermittent catheterisation (ρ = −0.181) and bowel management (ρ = −0.213), receiving rehabilitative care (ρ = −0.211), household income (ρ = −0.178), geographical region (ρ = −0.203) and having support from another parent in taking care of the child (ρ = −0.234). Linear regression showed parental stress was mostly explained by the child’s inability to walk (β = −0.248), practicing bowel management (β = −0.468) and having another adult to provide support in caring for the child (β = −0.228). Parents in northern Uganda had significantly higher scores compared to parents in other regions (Parental Distress, F = 5.467*; Parent–Child Dysfunctional Interaction, F = 8.815**; Difficult Child score, F = 10.489**). Conclusion Parents of children with spina bifida experience high levels of stress. To reduce this stress, rehabilitation services should focus on improving mobility. Advocacy to reduce stigmatisation

Small renal size in newborns with spina bifida: possible causes.

PubMed

Montaldo, Paolo; Montaldo, Luisa; Iossa, Azzurra Concetta; Cennamo, Marina; Caredda, Elisabetta; Del Gado, Roberto

2014-02-01

Previous studies reported that children with neural tube defects, but without any history of intrinsic renal diseases, have small kidneys when compared with age-matched standard renal growth. The aim of this study was to investigate the possible causes of small renal size in children with spina bifida by comparing growth hormone deficiency, physical limitations and hyperhomocysteinemia. The sample included 187 newborns with spina bifida. Renal sizes in the patients were assessed by using maximum measurement of renal length and the measurements were compared by using the Sutherland monogram. According to the results, the sample was divided into two groups--a group of 120 patients with small kidneys (under the third percentile) and a control group of 67 newborns with normal kidney size. Plasma total homocysteine was investigated in mothers and in their children. Serum insulin-like growth factor-1 (IGF-1) levels were measured. Serum IGF-1 levels were normal in both groups. Children and mothers with homocysteine levels >10 μmol/l were more than twice as likely to have small kidneys and to give to birth children with small kidneys, respectively, compared with newborns and mothers with homocysteine levels <10 μmol/l. An inverse correlation was also found between the homocysteine levels of mothers and kidney sizes of children (r = - 0.6109 P ≤ 0.01). It is highly important for mothers with hyperhomocysteinemia to be educated about benefits of folate supplementation in order to reduce the risk of small renal size and lower renal function in children.

Comparison of the Electromyographic Activation Level and Unilateral Selectivity of Erector Spinae during Different Selected Movements

ERIC Educational Resources Information Center

Guo, Lan-Yuen; Wang, Yu-Lin; Huang, Yu-Han; Yang, Chich-Haung; Hou, Yi-You; Harn, Hans I-Chen; You, Yu-Lin

2012-01-01

For patients with scoliosis, core stabilization exercises may be beneficial in improving muscle strength and trunk dynamic control. However, few studies have examined whether the erector spinae (ES) activation status during unilateral spinal extensor strengthening meets the guideline for patients with spinal scoliosis. To determine ES activation…

Mother and Child Depressive Symptoms in Youth with Spina Bifida: Additive, Moderator, and Mediator Models

ERIC Educational Resources Information Center

Schellinger, Kriston B.; Holmbeck, Grayson N.; Essner, Bonnie S.; Alvarez, Renae

2012-01-01

The purpose of the study was to examine the extent to which parenting behaviors influence the relation between maternal and child depressive symptoms in youth with spina bifida and a comparison sample. Previous research has found that maternal depression not only negatively impacts the mother-child relationship, but also places the child at risk…

Silver nanoparticles administered to chicken affect VEGFA and FGF2 gene expression in breast muscle and heart

NASA Astrophysics Data System (ADS)

Hotowy, Anna; Sawosz, Ewa; Pineda, Lane; Sawosz, Filip; Grodzik, Marta; Chwalibog, André

2012-07-01

Nanoparticles of colloidal silver (AgNano) can influence gene expression. Concerning trials of AgNano application in poultry nutrition, it is useful to reveal whether they affect the expression of genes crucial for bird development. AgNano were administered to broiler chickens as a water solution in two concentrations (10 and 20 ppm). After dissection of the birds, breast muscles and hearts were collected. Gene expression of FGF2 and VEGFA on the mRNA and protein levels were evaluated using quantitative polymerase chain reaction and enzyme-linked immunosorbent assay methods. The results for gene expression in the breast muscle revealed changes on the mRNA level ( FGF2 was up-regulated, P < 0.05) but not on the protein level. In the heart, 20 ppm of silver nanoparticles in drinking water increased the expression of VEGFA ( P < 0.05), at the same time decreasing FGF2 expression both on the transcriptional and translational levels. Changes in the expression of these genes may lead to histological changes, but this needs to be proven using histological and immunohistochemical examination of tissues. In general, we showed that AgNano application in poultry feeding influences the expression of FGF2 and VEGFA genes on the mRNA and protein levels in growing chicken.

Electromyographic activity of the erector spinae: The short-effect of one workday for welders with nonspecific chronic low back pain, an observational study.

PubMed

Mendes, André Augusto M T; de Freitas, Sandra Maria Sbeghen Ferreira; Amorin, César Ferreira; Cabral, Cristina Maria Nunes; Padula, Rosimeire Simprini

2018-02-06

This study aimed to evaluate the effect of one workday on pain and perceived exertion, muscular strength, and electromyographic activity of the erector spinae muscles in welders with and without low back pain. This is an observational cohort study. Twenty-two welders, metallurgical shipbuilding, were equally divided into 2 groups: low back pain and no low back pain. Pain and perceived exertion. Muscular strength by maximal voluntary contractions and electromyographic activity of right and left erector spinae muscles during maximal voluntary contractions and in the 3 welding positions for 2 periods of the workday (in the morning and at the end of the workday). At the end of workday, the pain increased significantly for the low back pain group (t(22) = 2.448; P= 0.023). The perceived exertion also increased significantly for both groups at the end of workday groups (F(1,22) = 8.570, P= 0.000) and periods (F(1,22) = 8.142, P= 0.000). There were no significant differences between groups and workday periods for muscular strength and electromyographic activity during maximal voluntary contractions of the erector spinae. There was no significance difference for electromyographic activity between groups and workday period and in the 3 welding positions. Although the pain and perceived exertion increased at the end of the workday, these results did not interfere in muscular strength and electromyographic activity of right and left erector spinae muscles. Thus, we can conclude that welders with chronic low back pain had a good physical capacity (muscular strength) and that muscle performance was maintained.

Resilience, self-esteem and self-compassion in adults with spina bifida.

PubMed

Hayter, M R; Dorstyn, D S

2014-02-01

Cross-sectional survey. To examine factors that may enhance and promote resilience in adults with spina bifida. Community-based disability organisations within Australia. Ninety-seven adults with a diagnosis of spina bifida (SB) completed a survey comprising of demographic questions in addition to standardised self-report measures of physical functioning (Craig Handicap Assessment and Reporting Technique), resilience (Connor-Davidson Resilience Scale, 10 item), self-esteem (Rosenberg Self-esteem Scale), self-compassion (Self-compassion Scale) and psychological distress (Depression Anxiety Stress Scales, 21 item). The majority (66%) of respondents reported moderate to high resilience. Physical disability impacted on coping, with greater CD-RISC 10 scores reported by individuals who were functionally independent in addition to those who experienced less medical co-morbidities. Significant correlations between resilience and psychological traits (self-esteem r=0.36, P<0.01; self-compassion r=0.40, P<0.01) were also noted. However, the combined contribution of these variables only accounted for 23% of the total variance in resilience scores (R(2)=0.227, F(5,94)=5.23, P<0.01). These findings extend current understanding of the concept of resilience in adults with a congenital physical disability. The suggestion is that resilience involves a complex interplay between physical determinants of health and psychological characteristics, such as self-esteem and self-compassion. It follows that cognitive behavioural strategies with a focus on self-management may, in part, contribute to the process of resilience in this group. Further large-scale and longitudinal research will help to confirm these findings.

Transition into adult healthcare services in Scotland: findings from a study concerning service users at the Scottish Spina Bifida Association.

PubMed

Levy, Sharon; Wynd, Andrew H D; Carachi, Robert

2014-11-01

Literature on interventions that enable young people with spina bifida and/or hydrocephalus to have smooth transition, into adult healthcare services, stress the need for the process to start early and to include all family members. The study reported here was set to quantify and articulate the experiences of service users who are or due to be going through the transition process in Scotland today. Focus group sessions, in the North of Scotland and in the 'Central Belt', captured rich qualitative data. A survey, sent to eligible participants on the Spina Bifida National database, offered complimentary data source. Despite the fact that the number of returned questionnaires was low (n = 20), data analysis identified a number of core recurring themes. These include issues concerning Communications, Respect, Choice and Control. Findings suggest that there is a significant chasm between the political rhetoric and the reality faced by young people with spina bifida moving to adult healthcare services. A possible way to facilitate successful transition of young people is using personal healthcare information as the locus for needed change. More research is needed to ascertain whether a 'Person-Centred Record', which is set to empower young people on their transition pathway, is an appropriate transition tool. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Children with Cerebral Palsy, Spina Bifida and Pragmatic Language Impairment: Differences and Similarities in Pragmatic Ability

ERIC Educational Resources Information Center

Holck, Pernille; Nettelbladt, Ulrika; Sandberg, Annika Dahlgren

2009-01-01

Pragmatically related abilities were studied in three clinical groups of children from 5 to 11 years of age; children with cerebral palsy (CP; n = 10), children with spina bifida and hydrocephalus (SBH; n = 10) and children with pragmatic language impairment (PLI; n = 10), in order to explore pragmatic abilities within each group. A range of…

The ethnobotany of Christ's Thorn Jujube (Ziziphus spina-christi) in Israel

PubMed Central

Dafni, Amots; Levy, Shay; Lev, Efraim

2005-01-01

This article surveys the ethnobotany of Ziziphus spina-christi (L.) Desf. in the Middle East from various aspects: historical, religious, philological, literary, linguistic, as well as pharmacological, among Muslims, Jews, and Christians. It is suggested that this is the only tree species considered "holy" by Muslims (all the individuals of the species are sanctified by religion) in addition to its status as "sacred tree " (particular trees which are venerated due to historical or magical events related to them, regardless of their botanical identity) in the Middle East. It has also a special status as "blessed tree" among the Druze. PMID:16270941

The ethnobotany of Christ's Thorn Jujube (Ziziphus spina-christi) in Israel.

PubMed

Dafni, Amots; Levy, Shay; Lev, Efraim

2005-09-28

This article surveys the ethnobotany of Ziziphus spina-christi (L.) Desf. in the Middle East from various aspects: historical, religious, philological, literary, linguistic, as well as pharmacological, among Muslims, Jews, and Christians. It is suggested that this is the only tree species considered "holy" by Muslims (all the individuals of the species are sanctified by religion) in addition to its status as "sacred tree " (particular trees which are venerated due to historical or magical events related to them, regardless of their botanical identity) in the Middle East. It has also a special status as "blessed tree" among the Druze.

The Effects of Bag Style on Muscle Activity of the Trapezius, Erector Spinae and Latissimus Dorsi During Walking in Female University Students

PubMed Central

Hardie, Rebecca; Haskew, Rachel; Harris, Joel; Hughes, Gerwyn

2015-01-01

Back pain is common in adolescents which has been associated with carrying a bag. However, there is little research examining the effects of bag style in female adolescents. The aim of the study was to investigate the effects of different bag conditions on muscle activity of the trapezius, erector spinae and latissimus dorsi muscles in female university students during walking. Twelve female university students walked on a treadmill for 5 minutes at 1.1 m/s during five conditions; control, 1 strapped rucksack, 2 strapped rucksack, ipsilateral shoulder strap and contralateral shoulder strap, each containing 10% bodyweight. Electromyography for the trapezius, erector spinae and latissimus dorsi was recorded for the last 30 s of each condition. Two-way ANOVA and paired t-tests were used to identify differences between right and left muscles and between bag conditions. Results showed that muscle activity of the left trapezius was significantly higher than the right trapezius during the 1 strap rucksack condition. For the left trapezius, the 2 strapped rucksack and the control condition had significantly lower muscle activity compared to the 1 strapped rucksack and the ipsilateral shoulder strap. For the left erector spinae muscle, there was significantly greater muscle activity when wearing the contralateral shoulder strap compared to the control. For the right erector spinae, significantly lower muscle activity was observed when wearing the 2 strapped rucksack compared to the ipsilateral shoulder strap and contralateral shoulder strap. There were no significant differences in muscle activity of the latissimus dorsi muscles between any of the bag conditions. These findings suggest that a two strapped rucksack should be used when carrying loads to reduce spinal muscle activity which may, in turn, reduce reports of back pain in female adolescents. PMID:25964808

The role of ethnicity and culture on functional status in children with spina bifida.

PubMed

Chowanadisai, Montida; de la Rosa Perez, Deeni L; Weitzenkamp, David A; Wilcox, Duncan T; Clayton, Gerald H; Wilson, Pamela E

2013-01-01

Spina bifida is a common cause of pediatric disability and more prevalent in the Hispanic population. Significant health disparities exist in minority populations. Culturally adapted health interventions have been attempted in conditions such as pediatric asthma with improvement. This study aims to explore the influence of ethnicity and culture with regards to functional status and care satisfaction. Study participants were recruited from the Children's Hospital Colorado Spinal Defects Clinic. Demographics and past medical and surgical history were obtained via chart review. A questionnaire assessed ethnicity, acculturation, self-care, mobility, bowel and bladder function, and care satisfaction. A total of 70 subjects with spina bifida were included in the statistical analysis. There was no difference in PEDI self-care and mobility scores between ethnicities. The Hispanic group had higher urinary incontinence rates, higher percentage with bladder accidents, and lower satisfaction with bladder management. Regarding bowel function, the Hispanic group had lower satisfaction rates and a trend towards lower bowel continence. Further work is needed to understand the social and cultural differences between Hispanic and Non-Hispanic children and their families that impact bowel and bladder continence and care satisfaction. Once identified, culturally sensitive interventions may be implemented that can alleviate these apparent health disparities.

Quality of life among children with spina bifida in Uganda.

PubMed

Sims-Williams, Helen J; Sims-Williams, Hugh P; Mbabazi Kabachelor, Edith; Warf, Benjamin C

2017-11-01

Children surviving after spina bifida repair often have significant disability, the consequences of which may be more profound in low-income countries. The aim of this cross-sectional study was to measure quality of life (QOL) reported by children with spina bifida in Uganda, and to define factors associated with QOL. QOL was measured using both the Health Utilities Index (HUI3) Tool and a visual analogue scale (VAS) marked from 0 to 10. In keeping with the WHO definition of QOL, further analysis was conducted using subjective QOL scores (using the VAS). Multivariate regression was used to investigate the association between VAS scores and prespecified variables: age, sex, hydrocephalus, mobility, urinary continence, school attendance and family size. Sixty two of 68 surviving children aged 10-14 were able to complete all aspects of the assessment. There was poor correlation between the VAS and HUI3 Tool (Pearson correlation 0.488). On multivariate regression, the following variables were associated with a significant change in the 10-point VAS (change in score; 95% CI): male sex (-1.45; -2.436 to -0.465), urinary continence (1.681; 0.190 to 3.172), large family size (-1.775; -2.773 to -0.777) and hydrocephalus (-1.382; -2.374 to -0.465). Urinary continence and family size are potentially modifiable, the former by simple and inexpensive medical management. Enhanced investment in community-based rehabilitation and support is urgently needed. Delivery of family planning services is a national priority in Uganda, and should be discussed with families as part of holistic care. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

The use of self-modeling to improve the swimming performance of spina bifida children.

PubMed Central

Dowrick, P W; Dove, C

1980-01-01

The use of edited videotape replay (which showed only "positive" behaviors) to improve the water skills of three spina bifida children, aged 5 to 10 years was examined. A multiple baseline across subjects design was used, and behavioral changes were observed to occur in close association with intervention. One child was given successive reapplications of videotaped self-modeling with continuing improvements. It appears that a useful practical technique has been developed. PMID:6988381

Wheelchair Shuttle Test for Assessing Aerobic Fitness in Youth With Spina Bifida: Validity and Reliability

PubMed Central

de Groot, Janke F.; Backx, Frank J.G.; Benner, Joyce; Kruitwagen, Cas L.J.J.; Takken, Tim

2017-01-01

Abstract Background Testing aerobic fitness in youth is important because of expected relationships with health. Objective The purpose of the study was to estimate the validity and reliability of the Shuttle Ride Test in youth who have spina bifida and use a wheelchair for mobility and sport. Design Ths study is a validity and reliability study. Methods The Shuttle Ride Test, Graded Wheelchair Propulsion Test, and skill-related fitness tests were administered to 33 participants for the validity study (age = 14.5 ± 3.1 y) and to 28 participants for the reliability study (age = 14.7 ± 3.3 y). Results No significant differences were found between the Graded Wheelchair Propulsion Test and the Shuttle Ride Test for most cardiorespiratory responses. Correlations between the Graded Wheelchair Propulsion Test and the Shuttle Ride Test were moderate to high (r = .55–.97). The variance in peak oxygen uptake (VO2peak) could be predicted for 77% of the participants by height, number of shuttles completed, and weight, with large prediction intervals. High correlations were found between number of shuttles completed and skill-related fitness tests (CI = .73 to −.92). Intraclass correlation coefficients were high (.77–.98), with a smallest detectable change of 1.5 for number of shuttles completed and with coefficients of variation of 6.2% and 6.4% for absolute VO2peak and relative VO2peak, respectively. Conclusions When measuring VO2peak directly by using a mobile gas analysis system, the Shuttle Ride Test is highly valid for testing VO2peak in youth who have spina bifida and use a wheelchair for mobility and sport. The outcome measure of number of shuttles represents aerobic fitness and is also highly correlated with both anaerobic performance and agility. It is not possible to predict VO2peak accurately by using the number of shuttles completed. Moreover, the Shuttle Ride Test is highly reliable in youth with spina bifida, with a good smallest detectable change for the

[Long-term outcome of monotherapy by Cohen ureterocystoneostomy for vesicoureteral reflux in spina bifida patients].

PubMed

Momose, H; Torimoto, K; Kishino, T; Ono, T; Joko, M

2001-05-01

The conventional surgical treatment for vesioureteral reflux (VUR) is spina bifida patients is ureterocystoneostomy. Various newer therapies, including augmentation enterocystoplasty and minimally invasive subureteral collagen injection, have been introduced. However, all of these procedures have specific advantages and disadvantages, and no guidelines for deciding on the surgical treatment of VUR in spina bifida patients have yet been established. In this study, the long-term outcome of the Cohen procedure, a method of ureterocystoneostomy, was examined. Among spina bifida patients in whom VUR was treated by the Cohen procedure alone from 1984 to 1989, 27 patients who could be followed up for 5 years or longer were enrolled in the study (11 males and 16 females, with a mean age of 13.4 years at surgery). In principle, they were followed up using annual cystography, excretory urography, and blood and urine tests. At the final assessment, they were examined for the presence at VUR and for morphological abnormalities of the urinary tract. Their renal function was also assessed. They were followed for 6 to 13 years (mean: 8.9 years), and the mean age at final assessment was 22.2 years. Among 42 ureters in the 27 patients examined, 38 ureters (90.5%) in 22 patients (81.5%) did not have VUR postoperatively. Four ureters in 4 patients had the recurrence of VUR, and in another patient new occurrence was detected postoperatively. Augmentation ileocystoplasty was performed to treat the postoperative decrease of bladder compliance in 4 patients. Among 22 patients who had hydronephrosis preoperatively, 9 (40.9%) showed improvement and none suffered from aggravation of this condition. None of the patients showed a decline of renal function, except for 1 who had a serum creatinine of 2.5 mg/dl preoperatively and developed end-stage renal failure at 7 years postoperatively. The Cohen procedure has an excellent anti-reflux effect. It is one of the therapeutic options for VUR in

A Novel Occulta-Type Spina Bifida Mediated by Murine Double Heterozygotes EphA2 and EphA4 Receptor Tyrosine Kinases.

PubMed

Abdullah, Nor Linda; Mohd-Zin, Siti W; Ahmad-Annuar, Azlina; Abdul-Aziz, Noraishah M

2017-01-01

Members of the Eph receptor tyrosine kinase have previously been implicated in cranial neural tube development. Failure of neural tube closure leads to the devastating conditions known as anencephaly and spina bifida. EphA2 and EphA4 are expressed at the tips of the closing spinal neural folds prior and during neural tube closure. We investigated the possible role of murine EphA2 and EphA4 during the last step of primary neural tube closure, which is adhesion and fusion. The individual mouse knockouts of EphA2 and EphA4 per se do not exhibit neural tube defects (NTDs). The embryos generated by the crossing of double heterozygotes Epha2 tm1Jrui/+ Epha4 rb-2J/+ displayed NTDs with a wide degree of severity including close exencephaly and close spina bifida (spina bifida occulta). Interestingly, mutants displaying NTDs had skin covering the underlying lesion. The tissue sections revealed the elevated neural folds had not adhered and fused. The phenotypes seen in Epha2 tm1Jrui/+ Epha4 rb-2J/+ double heterozygous embryos suggest both genes play a compensatory role with each other in the adhesion and fusion of the neural tube. In this study, there exists a >50% penetrance of NTDs in the mouse mutants, which genetically have a single allele each of EphA2 and EphA4 absent.

Prospective memory in adults with spina bifida

PubMed Central

Dennis, Maureen; Nelson, Rebekah; Jewell, Derryn; Fletcher, Jack M.

2011-01-01

Introduction Individuals with neurodevelopmental disorders have been observed to show accelerated cognitive aging or even dementia as early as 30 and 40 years of age. Memory deficits are an important component of age-related cognitive loss. Methods In this study, we investigated prospective memory, which is often impaired in aging, in a group of 32 adults with spina bifida meningomyelocele (SBM), including members of the oldest living cohort successfully treated with shunts to divert excess cerebrospinal fluid, ventriculomegaly, and hydrocephalus, who are now around 50 years of age. Seventeen typically developing adults provided a comparison group. Results The SBM and comparison groups differed in the prospective memory total score as well as in both time-based and event-based subscores. Prospective memory was impaired in both older and younger individuals with SBM. However, the percentage of individuals with impaired or poor prospective memory was three times higher in the older SBM group than in the younger SBM group. The results are considered in relation to specific features of the complex brain reorganization in SBM. PMID:20393850

Establishing use of crutches by a mentally retarded spina bifida child1

PubMed Central

Horner, R. Don

1971-01-01

A 5-yr-old mentally retarded spina bifida child was taught to walk with the aid of crutches. This behavior was developed through fading of physical prompting within a 10-step successive approximation sequence. Preliminary training to establish gait consisted of developing use of parallel bars through fading of physically modelled responses within a six-step successive approximation sequence. Use of parallel bars ceased during an extinction period and completely recovered upon being primed with one “free” reinforcement. Systematic use of natural reinforcers was employed as an aid in maintaining use of crutches. PMID:16795294

Auditory agnosia due to long-term severe hydrocephalus caused by spina bifida - specific auditory pathway versus nonspecific auditory pathway.

PubMed

Zhang, Qing; Kaga, Kimitaka; Hayashi, Akimasa

2011-07-01

A 27-year-old female showed auditory agnosia after long-term severe hydrocephalus due to congenital spina bifida. After years of hydrocephalus, she gradually suffered from hearing loss in her right ear at 19 years of age, followed by her left ear. During the time when she retained some ability to hear, she experienced severe difficulty in distinguishing verbal, environmental, and musical instrumental sounds. However, her auditory brainstem response and distortion product otoacoustic emissions were largely intact in the left ear. Her bilateral auditory cortices were preserved, as shown by neuroimaging, whereas her auditory radiations were severely damaged owing to progressive hydrocephalus. Although she had a complete bilateral hearing loss, she felt great pleasure when exposed to music. After years of self-training to read lips, she regained fluent ability to communicate. Clinical manifestations of this patient indicate that auditory agnosia can occur after long-term hydrocephalus due to spina bifida; the secondary auditory pathway may play a role in both auditory perception and hearing rehabilitation.

A Novel Occulta-Type Spina Bifida Mediated by Murine Double Heterozygotes EphA2 and EphA4 Receptor Tyrosine Kinases

PubMed Central

Abdullah, Nor Linda; Mohd-Zin, Siti W.; Ahmad-Annuar, Azlina; Abdul-Aziz, Noraishah M.

2017-01-01

Members of the Eph receptor tyrosine kinase have previously been implicated in cranial neural tube development. Failure of neural tube closure leads to the devastating conditions known as anencephaly and spina bifida. EphA2 and EphA4 are expressed at the tips of the closing spinal neural folds prior and during neural tube closure. We investigated the possible role of murine EphA2 and EphA4 during the last step of primary neural tube closure, which is adhesion and fusion. The individual mouse knockouts of EphA2 and EphA4 per se do not exhibit neural tube defects (NTDs). The embryos generated by the crossing of double heterozygotes Epha2tm1Jrui/+Epha4rb-2J/+ displayed NTDs with a wide degree of severity including close exencephaly and close spina bifida (spina bifida occulta). Interestingly, mutants displaying NTDs had skin covering the underlying lesion. The tissue sections revealed the elevated neural folds had not adhered and fused. The phenotypes seen in Epha2tm1Jrui/+Epha4rb-2J/+ double heterozygous embryos suggest both genes play a compensatory role with each other in the adhesion and fusion of the neural tube. In this study, there exists a >50% penetrance of NTDs in the mouse mutants, which genetically have a single allele each of EphA2 and EphA4 absent. PMID:29312933

Prenatal diagnosis of parapagus diprosopus dibrachius dipus twins with spina bifida in the first trimester using two- and three-dimensional ultrasound.

PubMed

Yang, Pei-Yin; Wu, Ching-Hua; Yeh, Guang-Perng; Hsieh, Charles Tsung-Che

2015-12-01

Here, we report a case of parapagus diprosopus twins with spina bifida diagnosed in the first trimester of pregnancy using two-dimensional (2D) and three-dimensional (3D) ultrasound. A 28-year-old Taiwanese woman, gravid 1, para 0, visited our hospital due to an abnormal fetal head shape discovered by 2D ultrasound at 11-weeks gestation. Parapagus diprosopus twins with spina bifida were diagnosed after ultrasound examination. The characteristics of parapagus diprosopus twins are more illustrative in 3D ultrasound than in 2D ultrasound. After counseling, termination of pregnancy was chosen by the couple. Although necropsy was declined, the gross appearance and radiograph of the abortus confirmed our diagnosis. With the help of 3D ultrasound, we made an early and definitive diagnosis of conjoined twins. Copyright © 2015. Published by Elsevier B.V.

Math and numeracy in young adults with spina bifida and hydrocephalus.

PubMed

Dennis, Maureen; Barnes, Marcia

2002-01-01

The developmental stability of poor math skill was studied in 31 young adults with spina bifida and hydrocephalus (SBH), a neurodevelopmental disorder involving malformations of the brain and spinal cord. Longitudinally, individuals with poor math problem solving as children grew into adults with poor problem solving and limited functional numeracy. As a group, young adults with SBH had poor computation accuracy, computation speed, problem solving, a ndfunctional numeracy. Computation accuracy was related to a supporting cognitive system (working memory for numbers), and functional numeracy was related to one medical history variable (number of lifetime shunt revisions). Adult functional numeracy, but not functional literacy, was predictive of higher levels of social, personal, and community independence.

The relationship between EMG activity and extensor moment generation in the erector spinae muscles during bending and lifting activities.

PubMed

Dolan, P; Adams, M A

1993-01-01

The relationship between EMG activity and extensor moment generation in the erector spinae muscles was investigated under isometric and concentric conditions. The full-wave rectified and averaged EMG signal was recorded from skin-surface electrodes located over the belly of the erector spinae at the levels of T10 and L3, and compared with measurements of extensor moment. The effects of muscle length and contraction velocity were studied by measuring the overall curvature (theta) and rate of change of curvature (d theta/dt) of the lumbar spine in the sagittal plane, using the '3-Space Isotrak' system. Isometric contractions were investigated with the subjects pulling up on a load cell attached to the floor. Hand height was varied to produce different amounts of lumbar flexion, as indicated by changes in lumbar curvature. The extensor moment was found to be linearly related to EMG activity, and the 'gradient' and 'intercept' of the relationship were themselves dependent upon the lumbar curvature at the time of testing. Concentric contractions were investigated with the subjects extending from a seated toe-touching position, at various speeds, while the torque exerted on the arm of a Cybex dynamometer was continuously measured. Under these conditions the EMG signal (E) was higher than the isometric signal (E0) associated with the same torque. E and E0 were related as follows: E0 = E/(1 + A d theta/dt), where A = 0.0014 exp (0.045P) and P = percentage lumbar flexion. This equation was used to correct the EMG data for the effect of contraction velocity. The corrected data were then used, in conjunction with the results of the isometric calibrations, to calculate the extensor moment generated by the erector spinae muscles during bending and lifting activities. The extensor moment can itself be used to calculate the compressive force acting on the lumbar spine.

Variation in definitions of urinary tract infections in spina bifida patients: a systematic review.

PubMed

Madden-Fuentes, Ramiro Jose; McNamara, Erin Rebekah; Lloyd, Jessica Catherine; Wiener, John Samuel; Routh, Jonathan Charles; Seed, Patrick Casey; Ross, Sherry Sedberry

2013-07-01

Urinary tract infections (UTIs) are a common source of morbidity among children with spina bifida (SB) and are a frequently reported outcome in studies of this patient population. However, the criteria for a diagnosis of UTI are often not stated. We evaluated the literature on SB patients for the criteria that authors use to define parameters in reporting UTI outcomes. Embase and Medline were queried with the medical subject heading terms “spinal dysraphism,” “myelomeningocele,” “infection,”and “urinary tract infection.” A second search with the exploded term“spina bifida” and “urinary tract infection” was performed. Original research studies reporting a UTI outcome in SB patients were included and evaluated by 2 independent reviewers for the presence of a UTI definition and diagnostic criteria. We identified 872 publications, of which 124 met inclusion criteria. Forty-five of 124 (36.3%) studies reporting UTI as an outcome provided a definition of UTI. Of 124 studies, 28 (22.6%) were published in pediatric journals and 69 (55.6%) in urology journals. A definition of UTI was provided in 11 (39.3%) and 26 (37.7%) studies, respectively. “Fever,culture, and symptoms” defined a UTI in 17 of 45 studies. Journal category and presence of UTI definitions did not correlate (P = .71). Explicit definitions for UTI are heterogeneous and infrequently applied in studies of SB patients, limiting study reliability and estimates of true UTI rates in this population. Future studies will benefit from the development and application of a standard definition for UTI in this population.

Prenatal diagnosis and genetic counseling in a case of spina bifida in a family with Waardenburg syndrome type I.

PubMed

Kujat, Annegret; Veith, Veit-Peter; Faber, Renaldo; Froster, Ursula G

2007-01-01

Waardenburg syndrome type I (WS I) is an autosomal dominant inherited disorder with an incidence of 1:45,000 in Europe. Mutations within the PAX3 gene are responsible for the clinical phenotype ranging from mild facial features to severe malformations detectable in prenatal diagnosis. Here, we report a four-generation family with several affected members showing various symptoms of WS I. We diagnosed the syndrome first in a pregnant young woman; she was referred because of a spina bifida in prenatal diagnosis. We performed clinical genetic investigations and molecular genetic analysis in all available family members. The phenotype displays a wide intra-familial clinical variability of pigmentary disturbances, facial anomalies and developmental defects. Molecular studies identified a novel splice site mutation within the PAX3 gene in intron 5 in all affected family members, but in none of the unaffected relatives. This case demonstrates the prenatal diagnosis of spina bifida in a fetus which leads to the initial diagnosis of WS I. Further studies could identify a private splice site mutation within the PAX3 gene responsible for the phenotype in this family.

Reading and writing skills in young adults with spina bifida and hydrocephalus.

PubMed

Barnes, Marcia; Dennis, Maureen; Hetherington, Ross

2004-09-01

Reading and writing were studied in 31 young adults with spina bifida and hydrocephalus (SBH). Like children with this condition, young adults with SBH had better word decoding than reading comprehension, and, compared to population means, had lower scores on a test of writing fluency. Reading comprehension was predicted by word decoding and listening comprehension. Writing was predicted by fine motor finger function, verbal intelligence, and short-term and working memory. These findings are consistent with cognitive models of reading and writing. Writing, but not reading, was related to highest level of education achieved and writing fluency predicted several aspects of functional independence. Reading comprehension and writing remain deficient in adults with SBH and have consequences for educational attainments and functional independence.

Lack of significant association between spina bifida and the fragile X syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiano, C.M.; Demb, H.B.; Brown, W.T.

1995-12-04

Folic acid is involved in two common disorders associated with developmental disabilities. Spina bifida is a malformation that may be associated with mental retardation, learning disabilities, and epilepsy. Its incidence can be reduced by the ingestion of folic acid before, and at the time of, conception. The fragile X syndrome is a genetic disorder which is the most common form of inherited mental retardation. This disorder can be diagnosed by the induction of fragile sites on the X chromosome which is cultured in a medium deficient in folic acid. In several studies, folic acid was reported to alleviate some ofmore » the developmental and behavioral manifestations associated in the fragile X syndrome, while in others, it has no effect. 9 refs.« less

Outcomes of Clinicians, Caregivers, Family Members and Adults with Spina Bifida Regarding Receptivity to use of the iMHere mHealth Solution to Promote Wellness

PubMed Central

Fairman, Andrea D.; Dicianno, Brad E.; Datt, Nicole; Garver, Amanda; Parmanto, Bambang; McCue, Michael

2013-01-01

The purpose of this study was to gather information regarding the receptivity of clinicians, caregivers and family members, and adults with spina bifida (SB) to the use of a mHealth application, iMobile Health and Rehabilitation (iMHere) system. Surveys were administered to end user groups in conjunction with a conference presentation at the Spina Bifida Association’s 38th Annual Conference. The survey results were obtained from a total of 107 respondents. Likert scale and qualitative results are provided in consideration of future application of the iMHere system in clinical practice. The results of this survey indicate respondents were receptive and supportive with regard to adopting such a system for personal and professional use. Challenges likely to be encountered in the introduction of the iMHere system are also revealed and discussed. PMID:25945209

Differences between two subgroups of low back pain patients in lumbopelvic rotation and symmetry in the erector spinae and hamstring muscles during trunk flexion when standing.

PubMed

Kim, Min-hee; Yoo, Won-gyu; Choi, Bo-ram

2013-04-01

The present study was performed to examine lumbopelvic rotation and to identify asymmetry of the erector spinae and hamstring muscles in people with and without low back pain (LBP). The control group included 16 healthy subjects, the lumbar-flexion-rotation syndrome LBP group included 17 subjects, and the lumbar-extension-rotation syndrome LBP group included 14 subjects. Kinematic parameters were recorded using a 3D motion-capture system, and electromyography parameters were measured using a Noraxon TeleMyo 2400T. The two LBP subgroups showed significantly more lumbopelvic rotation during trunk flexion in standing than did the control group. The muscle activity and flexion-relaxation ratio asymmetries of the erector spinae muscles in the lumbar-flexion-rotation syndrome LBP group were significantly greater than those in the control group, and the muscle activity and flexion-relaxation ratio asymmetry of the hamstring muscles in the lumbar-extension-rotation syndrome LBP group were significantly greater than those in the control group. Imbalance or asymmetry of passive tissue could lead to asymmetry of muscular activation. Muscle imbalance can cause asymmetrical alignment or movements such as unexpected rotation. The results showed a greater increase in lumbopelvic rotation during trunk flexion in standing among the lumbar-flexion-rotation syndrome and lumbar-extension-rotation syndrome LBP groups compared with the control group. The differences between the two LBP subgroups may be a result of imbalance and asymmetry in erector spinae and hamstring muscle properties. Copyright © 2012 Elsevier Ltd. All rights reserved.

Daily time management in children with spina bifida.

PubMed

Persson, Marika; Janeslätt, Gunnel; Peny-Dahlstrand, Marie

2017-12-11

Spina bifida (SB) often results in a complex disability and can also cause cognitive dysfunction. No previous study has investigated the ability to adapt to time in children with SB. This ability is crucial for an individual's possibility to develop autonomy in life. The purpose of this study was to investigate whether children aged 10-17 with SB have lower time-processing abilities than typically-developing children, and to describe the profile of time-processing in children with SB. Participants comprised a consecutive sample of 21 children (drawn from a geographical cohort of 45) aged 10-17 years (mean: 14 years, SD: 2 years); 13 were boys. The instruments used were KaTid-Y, Time-S, and Time-P. The children with SB had lower time-processing abilities than typically-developing children (52.4% under -2SD), particularly difficulties to orient to and to estimate objective time, to understand time perspectives and with time planning. They also self-rated low use of strategies to adapt to time. The parents rated their children as having extensive difficulties in daily time management. The low time-processing ability found in children with SB is likely to be an important contributing factor to low autonomy and independence.

Motor Contingency Learning and Infants with Spina Bifida

PubMed Central

Taylor, Heather B.; Barnes, Marcia A.; Landry, Susan H.; Swank, Paul; Fletcher, Jack M.; Huang, Furong

2014-01-01

Infants with Spina Bifida (SB) were compared to typically developing infants (TD) using a conjugate reinforcement paradigm at 6 months-of-age (n = 98) to evaluate learning, and retention of a sensory-motor contingency. Analyses evaluated infant arm-waving rates at baseline (wrist not tethered to mobile), during acquisition of the sensory-motor contingency (wrist tethered), and immediately after the acquisition phase and then after a delay (wrist not tethered), controlling for arm reaching ability, gestational age, and socioeconomic status. Although both groups responded to the contingency with increased arm-waving from baseline to acquisition, 15% to 29% fewer infants with SB than TD were found to learn the contingency depending on the criterion used to determine contingency learning. In addition, infants with SB who had learned the contingency had more difficulty retaining the contingency over time when sensory feedback was absent. The findings suggest that infants with SB do not learn motor contingencies as easily or at the same rate as TD infants, and are more likely to decrease motor responses when sensory feedback is absent. Results are discussed with reference to research on contingency learning in infants with and without neurodevelopmental disorders, and with reference to motor learning in school-age children with SB. PMID:23298791

Motor contingency learning and infants with Spina Bifida.

PubMed

Taylor, Heather B; Barnes, Marcia A; Landry, Susan H; Swank, Paul; Fletcher, Jack M; Huang, Furong

2013-02-01

Infants with Spina Bifida (SB) were compared to typically developing infants (TD) using a conjugate reinforcement paradigm at 6 months-of-age (n = 98) to evaluate learning, and retention of a sensory-motor contingency. Analyses evaluated infant arm-waving rates at baseline (wrist not tethered to mobile), during acquisition of the sensory-motor contingency (wrist tethered), and immediately after the acquisition phase and then after a delay (wrist not tethered), controlling for arm reaching ability, gestational age, and socioeconomic status. Although both groups responded to the contingency with increased arm-waving from baseline to acquisition, 15% to 29% fewer infants with SB than TD were found to learn the contingency depending on the criterion used to determine contingency learning. In addition, infants with SB who had learned the contingency had more difficulty retaining the contingency over time when sensory feedback was absent. The findings suggest that infants with SB do not learn motor contingencies as easily or at the same rate as TD infants, and are more likely to decrease motor responses when sensory feedback is absent. Results are discussed with reference to research on contingency learning in infants with and without neurodevelopmental disorders, and with reference to motor learning in school-age children with SB.

Prediction of maximal surface electromyographically based voluntary contractions of erector spinae muscles from sonographic measurements during isometric contractions.

PubMed

Cuesta-Vargas, Antonio I; González-Sánchez, Manuel

2014-03-01

Currently, there are no studies combining electromyography (EMG) and sonography to estimate the absolute and relative strength values of erector spinae (ES) muscles in healthy individuals. The purpose of this study was to establish whether the maximum voluntary contraction (MVC) of the ES during isometric contractions could be predicted from the changes in surface EMG as well as in fiber pennation and thickness as measured by sonography. Thirty healthy adults performed 3 isometric extensions at 45° from the vertical to calculate the MVC force. Contractions at 33% and 100% of the MVC force were then used during sonographic and EMG recordings. These measurements were used to observe the architecture and function of the muscles during contraction. Statistical analysis was performed using bivariate regression and regression equations. The slope for each regression equation was statistically significant (P < .001) with R(2) values of 0.837 and 0.986 for the right and left ES, respectively. The standard error estimate between the sonographic measurements and the regression-estimated pennation angles for the right and left ES were 0.10 and 0.02, respectively. Erector spinae muscle activation can be predicted from the changes in fiber pennation during isometric contractions at 33% and 100% of the MVC force. These findings could be essential for developing a regression equation that could estimate the level of muscle activation from changes in the muscle architecture.

Inter-Tester Reliability and Precision of Manual Muscle Testing and Hand-Held Dynamometry in Lower Limb Muscles of Children with Spina Bifida

ERIC Educational Resources Information Center

Mahony, Kate; Hunt, Adrienne; Daley, Deborah; Sims, Susan; Adams, Roger

2009-01-01

Reliability and measurement precision of manual muscle testing (MMT) and hand-held dynamometry (HHD) were compared for children with spina bifida. Strength measures were obtained of the hip flexors, hip abductors, and knee extensors of 20 children (10 males, 10 females; mean age 9 years 10 months; range: 5 to 15 years) by two experienced physical…

The development and evaluation of content validity of the Zambia Spina Bifida Functional Measure: Preliminary studies

PubMed Central

Amosun, Seyi L.; Shilalukey-Ngoma, Mary P.; Kafaar, Zuhayr

2017-01-01

Background Very little is known on outcome measures for children with spina bifida (SB) in Zambia. If rehabilitation professionals managing children with SB in Zambia and other parts of sub-Saharan Africa are to instigate measuring outcomes routinely, a tool has to be made available. The main objective of this study was to develop an appropriate and culturally sensitive instrument for evaluating the impact of the interventions on children with SB in Zambia. Methods A mixed design method was used for the study. Domains were identified retrospectively and confirmation was done through a systematic review study. Items were generated through semi-structured interviews and focus group discussions. Qualitative data were downloaded, translated into English, transcribed verbatim and presented. These were then placed into categories of the main domains of care deductively through the process of manifest content analysis. Descriptive statistics, alpha coefficient and index of content validity were calculated using SPSS. Results Self-care, mobility and social function were identified as main domains, while participation and communication were sub-domains. A total of 100 statements were generated and 78 items were selected deductively. An alpha coefficient of 0.98 was computed and experts judged the items. Conclusions The new functional measure with an acceptable level of content validity titled Zambia Spina Bifida Functional Measure (ZSBFM) was developed. It was designed to evaluate effectiveness of interventions given to children with SB from the age of 6 months to 5 years. Psychometric properties of reliability and construct validity were tested and are reported in another study. PMID:28951850

A two-view ultrasound CAD system for spina bifida detection using Zernike features

NASA Astrophysics Data System (ADS)

Konur, Umut; Gürgen, Fikret; Varol, Füsun

2011-03-01

In this work, we address a very specific CAD (Computer Aided Detection/Diagnosis) problem and try to detect one of the relatively common birth defects - spina bifida, in the prenatal period. To do this, fetal ultrasound images are used as the input imaging modality, which is the most convenient so far. Our approach is to decide using two particular types of views of the fetal neural tube. Transcerebellar head (i.e. brain) and transverse (axial) spine images are processed to extract features which are then used to classify healthy (normal), suspicious (probably defective) and non-decidable cases. Decisions raised by two independent classifiers may be individually treated, or if desired and data related to both modalities are available, those decisions can be combined to keep matters more secure. Even more security can be attained by using more than two modalities and base the final decision on all those potential classifiers. Our current system relies on feature extraction from images for cases (for particular patients). The first step is image preprocessing and segmentation to get rid of useless image pixels and represent the input in a more compact domain, which is hopefully more representative for good classification performance. Next, a particular type of feature extraction, which uses Zernike moments computed on either B/W or gray-scale image segments, is performed. The aim here is to obtain values for indicative markers that signal the presence of spina bifida. Markers differ depending on the image modality being used. Either shape or texture information captured by moments may propose useful features. Finally, SVM is used to train classifiers to be used as decision makers. Our experimental results show that a promising CAD system can be actualized for the specific purpose. On the other hand, the performance of such a system would highly depend on the qualities of image preprocessing, segmentation, feature extraction and comprehensiveness of image data.

[Prevalence of Gastroschisis, Omphalocele, Spina Bifida and Orofacial Clefts of Neonates from January 2000 to December 2010 in Leipzig, Saxony, Saxony-Anhalt and Germany].

PubMed

Bremer, S; Kiess, W; Thome, U; Knüpfer, M; Bühligen, U; Vogel, M; Friedrich, A; Janisch, U; Rißmann, A

2018-02-01

Malformations are the most common cause of death in infancy. Numerous studies indicate an increased prevalence of malformations in neonates in recent years in some countries around the world. This study analyzed local and national trends of the prevalences of gastroschisis, omphalocele, spina bifida and orofacial clefts during 2000 till 2010 in Leipzig, Saxony, Saxony-Anhalt and Germany. The prevalence of neonatal malformations was studied retrospectively from January 2000 till December 2010 using 4 sources from Leipzig, Saxony, Saxony-Anhalt and Germany. Between 2000 and 2010, the prevalence in Germany and in Saxony, respectively was 1.97/2.12 (gastroschisis), 1.63/1.48 (omphalocele), 5.80/8.11 (orofacial clefts) and 2.92/2.50 (spina bifida) of 10 000 live births. In Saxony, a small increase in prevalence was detected (OR/year: 1.01-1.09). In Germany, the prevalence of malformations also increased significantly (OR/year: 1.01-1.04) with the exception of the prevalence of spina bifida which seemed to decline (OR/year 0.986 (0.97-1.0), p-adjust=0.04). Whether or not there has been an actual increase in the prevalence of neonatal malformations in Germany over the years or the apparent increase is just due to bias, coding errors, multiple reporting and/or false registration and codification remains unclear. Importantly, in Germany, since prevalence of malformations is monitored prospectively only in Saxony-Anhalt and Rhineland-Palatinate, only in these states is it possible to recognize recent changes. For early identification of changes in prevalence and timely implementation of preventive measures, a nationwide register or additional regional registers are deemed necessary. © Georg Thieme Verlag KG Stuttgart · New York.

Osteoporosis in paediatric patients with spina bifida.

PubMed

Marreiros, Humberto; Marreiros, Humberto Filipe; Loff, Clara; Calado, Eulalia

2012-01-01

The prevalence and morbidity associated with osteoporosis and fractures in patients with spina bifida (SB) highlight the importance of osteoporosis prevention and treatment in early childhood; however, the issue has received little attention. The method for the selection of appropriate patients for drug treatment has not been clarified. To review the literature concerning fracture risks and low bone density in paediatric patients with SB. We looked for studies describing state-of-the-art treatments and for prevention of secondary osteoporosis. Articles were identified through a search in the electronic database (PUBMED) supplemented with reviews of the reference lists of selected papers. The main outcome measures were incidence of fractures and risk factors for fracture, an association between bone mineral density (BMD) and occurrence of fracture, risk factors of low BMD, and effects of pharmacological and non-pharmacological treatments on BMD and on the incidence of fractures. We considered as a secondary outcome the occurrence of fractures in relation to the mechanism of injury. Results indicated that patients with SB are at increased risk for fractures and low BMD. Risk factors that may predispose patients to fractures include higher levels of neurological involvement, non-ambulatory status, physical inactivity, hypercalciuria, higher body fat levels, contractures, and a previous spontaneous fracture. Limitations were observed in the number and quality of studies concerning osteoporosis prevention and treatment in paediatric patients with SB. The safety and efficiency of drugs to treat osteoporosis in adults have not been evaluated satisfactorily in children with SB.

Silver nanoparticle-doped zirconia capillaries for enhanced bacterial filtration.

PubMed

Wehling, Julia; Köser, Jan; Lindner, Patrick; Lüder, Christian; Beutel, Sascha; Kroll, Stephen; Rezwan, Kurosch

2015-03-01

Membrane clogging and biofilm formation are the most serious problems during water filtration. Silver nanoparticle (Agnano) coatings on filtration membranes can prevent bacterial adhesion and the initiation of biofilm formation. In this study, Agnano are immobilized via direct reduction on porous zirconia capillary membranes to generate a nanocomposite material combining the advantages of ceramics being chemically, thermally and mechanically stable with nanosilver, an efficient broadband bactericide for water decontamination. The filtration of bacterial suspensions of the fecal contaminant Escherichia coli reveals highly efficient bacterial retention capacities of the capillaries of 8 log reduction values, fulfilling the requirements on safe drinking water according to the U.S. Environmental Protection Agency. Maximum bacterial loading capacities of the capillary membranes are determined to be 3×10(9)bacterialcells/750mm(2) capillary surface until back flushing is recommendable. The immobilized Agnano remain accessible and exhibit strong bactericidal properties by killing retained bacteria up to maximum bacterial loads of 6×10(8)bacterialcells/750mm(2) capillary surface and the regenerated membranes regain filtration efficiencies of 95-100%. Silver release is moderate as only 0.8% of the initial silver loading is leached during a three-day filtration experiment leading to average silver contaminant levels of 100μg/L. Copyright © 2014 Elsevier B.V. All rights reserved.

Dynamics of Conduit Flow and Fragmentation of Trachytic Versus Rhyolitic Eruptions

NASA Astrophysics Data System (ADS)

Papale, P.; Giordano, D.; del Seppia, D.; Romano, C.; Dingwell, D. B.

We have performed a systematic investigation of the dynamics of ascent and fragmen- tation of trachitic magmas from Phlegrean Fields, and have compared such dynamics with those of the more common and more thoroughly investigated rhyolitic eruptions. The investigation involved experimental as well as numerical studies. Knowledge of the viscosity of trachytic magmas is crucial, since viscosity is one of the most im- portant controlling factors in magma ascent dynamics. We have performed a series of measurements of the dry and hydrous viscosity of trachytic liquids representative of the glassy portion of pumice from the Campanian Ignimbrite, Agnano Monte Spina, and Monte Nuovo eruptions of Phlegrean Fields, spanning a time interval from 36,000 BP to 1538 AD, and an intensity range of about 4 orders of magnitude. The results show that for water contents larger than 1-2 wt% trachytic viscosities are within one order of magnitude less than rhyolitic viscosities. On the contrary, the calculated sol- ubility of water in trachytic liquids is significantly higher than in rhyolitic liquids. We have simulated the steady, multiphase flow of gas and liquid magma, or pyro- clasts above fragmentation, for trachytic and rhyolitic compositions, by parameteris- ing quantities like the total water content and the conduit size. All else being equal, the higher water solubility of trachytes and substantially similar liquid viscosity with respect to rhyolites yields a lower mixture viscosity and lower pressure gradient in the deep conduit region for the former magma type. This results in the achievement of fragmentation conditions, calculated as the condition at which the strain rate in magma becomes too large to be supported by viscous flow, which are hundreds to thousands of meters higher in the conduit for trachytes than for rhyolites. The fragmentation vesic- ularity of trachytes is also systematically larger than that of rhyolites, still remaining in the 0.6 U 0.85 range which is

Can Naturoptics fund Naturopathic Universities to Develop Interlocked Mentoring Relationships with Proposed Universities to Check Sensitivities of Individuals with Spina Bifida, to Environmentally Generated EMF Information about 'Quakes, Hurricanes, etc.?

NASA Astrophysics Data System (ADS)

McLeod, David M.; Ataide, Italani; McLeod, Roger D.

2006-03-01

Individuals harboring the herpes zoster virus following chicken pox, are susceptible to attacks of shingles. They may indicate peculiar awareness of pricking `pin and needle' sensations and co-symptoms of tinnitus and/or Meuniere's syndrome. RDM used similar symptoms in FL to predict the earthquake ninety miles north of Guantanamo bay in 1998. An astounding burial site in Florida from over six thousand years ago had a teenaged boy with severe spina bifida, with non-Asian genes, who could not have survived without very capable health support. Two youthful individuals likewise afflicted with spina bifida were unearthed from one site at Pompeii, entombed by the eruption of Vesuvius, August 24 and 25, CE 79. We know how to locate sites, active with EMF, which have tornado, hurricane and earthquake associations, and would like to foster joint research also involving Hawaiian and other volcanoes.

Validation of QUALAS-T, a health-related quality of life instrument for teenagers with spina bifida

PubMed Central

Misseri, Rosalia; Whittam, Benjamin; Casey, Jessica T.; Yang, David Y.; Raposo, Sonia-Maria; King, Shelly J.; Kaefer, Martin; Rink, Richard C.; Cain, Mark P.

2017-01-01

Introduction We aimed to develop and validate a self-reported QUAlity of Life Assessment in Spina bifida for Teenagers (QUALAS-T). Material and methods We drafted a 46-question pilot instrument using a patient-centered comprehensive item generation/refinement process. A group of 13–17 years olds with spina bifida (SB) was recruited online via social media and in person at SB clinics (2013–2015). Healthy controls were recruited during routine pediatrician visits. Final questions were identified based on clinical relevance, factor analysis and domain psychometrics. Teenagers with SB completed the validated generic Kidscreen-27 instrument. Results Median age of 159 participants was 15.2 years (42.0% male, 77.4% Caucasian), similar to 58 controls (p ≥ 0.06). There were 102 online and 57 clinic participants (82.8% of eligible). Patients, parents and an expert panel established face and content validity of the 2-domain, 10-question QUALAS-T. Internal consistency and test-retest reliability were high for the Family and Independence and Bladder and Bowel domains (Cronbach's alpha: 0.76–0.78, ICC: 0.72–0.75). The Bladder and Bowel domain is the same for QUALAS-T , QUALAS-A for adults and QUALAS-C for children. Correlations between QUALAS-T domains were low (r = 0.34), indicating QUALAS-T can differentiate between distinct HRQOL components. Correlations between QUALAS-T and Kidscreen-27 were also low (r ≤0.41). QUALAS-T scores were lower in teenagers with SB than without (p <0.0001). Conclusions QUALAS-T is a short, valid HRQOL tool for adolescents with SB, applicable in clinical and research settings. Since the Bladder & Bowel domains for all QUALAS versions are the same, Bladder and Bowel HRQOL can be measured on the same scale from age 8 through adulthood. PMID:29104796

Phenolic profile, antioxidant capacity of five Ziziphus spina-christi (L.) Willd provenances and their allelopathic effects on Trigonella foenum-graecum L. and Lens culinaris L. seeds.

PubMed

Elaloui, M; Ghazghazi, H; Ennajah, A; Manaa, S; Guezmir, W; Karray, N B; Laamouri, A

2017-05-01

The aim of this work was to evaluate some secondary metabolites, antioxidant activity of methanolic leaf extracts of five Ziziphus spina-christi provenances (INRGREF, Tozeur, Degueche, Nafta and Kebelli) and their allelopathic effects on Trigonella foenum-graecum and Lens culinaris. Leaves were collected during 2013 and 2014. Total phenols, flavonoids, tannins and antioxidant activity were evaluated using the Folin ciocalteux, Aluminum trichloride, vanillin and scavenging activity on 22-diphenyl-1-picrylhydrazyl (DPPH) radical methods, respectively. Total phenols, tannins and flavonoids were present, at levels of 57.41 mg GAE/g DW, 31.98 mg RE/g DW and 14.68 μg CE/g DW, respectively. The high antioxidant activity (0.086 μg/mL) was noted in kebelli provenance (2013). The highest germination, plumule and radicle lengths of tested species were observed in INRGREF provenance. Z. spina-christi leaf extracts may be suggested in foods and pharmaceutical industries. Leaf extracts could also provide a natural herbicide with a positive impact on the environment.

Adolescents with spina bifida. How they see their situation.

PubMed Central

Dorner, S

1976-01-01

Forty-six adolescents with spina bifida were interviewed at home to find out how they felt about their situation. Some degree of misery was very common indeed but was more likely to be severe in girls than in boys. About half the girls had, on some occasion in the past year, felt that life was hopeless or not worth living. Since these feelings are related to their social isolation outside school, they might be alleviated by improved opportunities for contract with peers. This seems particularly important in view of the capacity of most teenagers to make reasonable relationships where the opportunity exists, e.g. at school or within the family. Over half those who had left school were either unemployed or very dissatisfied with their job. In addition to worries about work, preoccupations about sexual relatinships, sexual function, and marriage were common. About two-thirds of the teenagers hoped to get married and half of these thought they could have children. Girls were particularly worried about their capacity to conceive and boys had understandable concerns about potency. Very few had consulted anyone about this or had had advice about the genetic aspects of the condition and there is a clear need for adequate counseling to help such teenagers to distinguish between real and imagined fears about the consequences of their condition. PMID:782378

Sonographic detection of open spina bifida in the first trimester: review of the literature.

PubMed

Meller, César; Aiello, Horacio; Otaño, Lucas

2017-07-01

In the beginnings, sonographic diagnosis of open spina bifida (OSB) relied on the meticulous scanning of the fetal vertebrae for abnormalities but many defects were missed. After the mid-1980s, however, with the description of the intracranial findings in the second trimester (the "lemon sign" and the "banana sign"), the prenatal diagnosis of OSB was enhanced. In the last 2 decades, there has been widespread uptake of routine ultrasound examination in the first trimester of pregnancy with the purpose of the measurement of fetal crown-rump length to determine gestational age, to screen for trisomy 21 and other aneuploidies, mainly with the nuchal translucency, and for diagnosis of many major abnormalities. Many papers were published focusing on early diagnosis of myelomeningocele (MMC), and the objective of this review is to summarize the different techniques described regarding prenatal diagnosis of OSB in the first trimester of pregnancy.

Prospective and Episodic Memory in Relation to Hippocampal Volume in Adults with Spina Bifida Myelomeningocele

PubMed Central

Treble-Barna, Amery; Juranek, Jenifer; Stuebing, Karla K.; Cirino, Paul T.; Dennis, Maureen; Fletcher, Jack M.

2014-01-01

The present study examined prospective and episodic memory in relation to age, functional independence, and hippocampal volume in younger to middle-aged adults with spina bifida myelomeningocele (SBM) and typically developing (TD) adults. Prospective and episodic memory, as well as hippocampal volume, were reduced in adults with SBM relative to TD adults. Neither memory performance nor hippocampal volume showed greater decrements in older adults. Lower hippocampal volume was associated with reduced prospective memory in adults with SBM, and this relation was specific to the hippocampus and not to a contrast structure, the amygdala. Prospective memory mediated the relation between hippocampal volume and functional independence in adults with SBM. The results add to emerging evidence for reduced memory function in adults with SBM, and provide quantitative evidence for compromised hippocampal macrostructure as a neural correlate of reduced memory in this population. PMID:25068670

Fixed-node quantum Monte Carlo

NASA Astrophysics Data System (ADS)

Anderson, James B.

Quantum Monte Carlo methods cannot at present provide exact solutions of the Schrödinger equation for systems with more than a few electrons. But, quantum Monte Carlo calculations can provide very low energy, highly accurate solutions for many systems ranging up to several hundred electrons. These systems include atoms such as Be and Fe, molecules such as H2O, CH4, and HF, and condensed materials such as solid N2 and solid silicon. The quantum Monte Carlo predictions of their energies and structures may not be `exact', but they are the best available. Most of the Monte Carlo calculations for these systems have been carried out using approximately correct fixed nodal hypersurfaces and they have come to be known as `fixed-node quantum Monte Carlo' calculations. In this paper we review these `fixed node' calculations and the accuracies they yield.

Serial casting versus stretching technique to treat knee flexion contracture in children with spina bifida: a comparative study.

PubMed

Al-Oraibi, S; Tariah, Hashem Abu; Alanazi, Abdullah

2013-01-01

Severe knee contractures that develop soon after muscle imbalance may not improve with stretching exercises and splinting. An alternative treatment is serial casting, which has been used to promote increased range of motion. The purpose of this study was to compare the effectiveness of using serial casting and passive stretching approaches to treat knee flexion contracture in children with spina bifida. In a pre/post randomized controlled study, ten participants were included in the serial casting group, while eight participants were included in the passive stretching intervention group. The degree of knee extension was measured at baseline, immediately after intervention, and at a one-year follow-up using a standard goniometer. Both groups showed significant improvements in the degree of flexion contracture at the post-treatment evaluation and the follow-up evaluation. The serial casting group showed significant improvements in knee flexion contracture at the post-treatment evaluation, t (9)=13.4, p < 0.001, and the one-year follow-up evaluation, t (9) = 7.46, p < 0.001. The passive stretching group also showed significant improvements in knee flexion contracture at the post-treatment evaluation, t (7) =2.6, p < 0.05, and the one-year follow-up evaluation, t (7) = 3.6, p < 0.05. However, statistically significant improvements in the serial casting group compared with passive stretching group in relation to the degree of flexion contracture were found at the immediate post-treatment evaluation, F(1, 15)=246, p=0.0001, and the one-year follow-up evaluation, F (1, 15)=51.5, p=0.0001. The outcomes of this study provide the first evidence that serial casting may be a useful intervention in treating knee flexion contracture in children with spina bifida. However, further investigations into serial casting, as well as investigations into the use of serial casting with other interventions, are warranted.

Complications of Delivery Among Mothers with Spina Bifida.

PubMed

Shepard, Courtney L; Yan, Phyllis L; Kielb, Stephanie J; Wittmann, Daniela A; Quint, Elisabeth H; Kraft, Kate H; Hollingsworth, John M

2018-06-13

To determine rates and types of peripartum morbidity among delivering women with spina bifida (SB) compared to those without SB. The rates of pregnancy and delivery among women with SB have been significantly increasing. Current knowledge of peripartum outcomes for these women is limited. Using 2004-2013 National Inpatient Sample data, we identified all hospitalizations for delivery, distinguishing between women with and without SB. Using a code-based algorithm, we determined whether a complication occurred during the hospitalization. We then fit a series of multivariable logistic models to examine for associations between a complication occurrence during vaginal or cesarean delivery and a woman's SB status. We identified 38,319,814 weighted admissions for delivery, 9,516 of which were made by women with SB. Women with SB had a significantly higher rate of cesarean delivery than women without this diagnosis (53% v 32%, p<0.001). The 46.7% of women with SB who delivered vaginally did not have significantly increased odds of a complication associated with their delivery compared to women without SB [odds ratio (OR) 1.15, 95% confidence interval (CI) 0.99 to 1.34, p=0.066]. However, women with SB who underwent a cesarean delivery did have higher odds of morbidity compared to those without (OR 1.49, 95% CI 1.25 to 1.78, p<0.001). Common complications included preterm delivery, urinary tract infection, hematologic event, and blood transfusion. Compared to women without SB, those with SB deliver more frequently by cesarean section and have higher odds of morbidity associated with cesarean delivery, but not vaginal delivery. Copyright © 2018. Published by Elsevier Inc.

Selective and sustained attention in children with spina bifida myelomeningocele.

PubMed

Caspersen, Ida Dyhr; Habekost, Thomas

2013-01-01

Spina bifida myelomeningocele (SBM) is a neural tube defect that has been related to deficits in several cognitive domains including attention. Attention function in children with SBM has often been studied using tasks that are confounded by complex motor demands or tasks that do not clearly distinguish perceptual from response-related components of attention. We used a verbal-report paradigm based on the Theory of Visual Attention (Bundesen, 1990) and a new continuous performance test, the Dual Attention to Response Task (Dockree et al., 2006), for measuring parameters of selective and sustained attention in 6 children with SBM and 18 healthy control children. The two tasks had minimal motor demands, were functionally specific and were sensitive to minor deficits. As a group, the children with SBM were significantly less efficient at filtering out irrelevant stimuli. Moreover, they exhibited frequent failures of sustained attention and response control in terms of omission errors, premature responses, and prolonged inhibition responses. All 6 children with SBM showed deficits in one or more parameters of attention; for example, three patients had elevated visual perception thresholds, but large individual variation was evident in their performance patterns, which highlights the relevance of an effective case-based assessment method in this patient group. Overall, the study demonstrates the strengths of a new testing approach for evaluating attention function in children with SBM.

[The diagnostic process in spina bifida: parents perception and viewpoint of clinical specialists].

PubMed

Herb, G; Streeck, S

1995-01-01

This is a study of the subjective experience of communicative understanding between parents of spina bifida children and medical personnel. Research methods include content analysis of data from semi-structured interviews, a questionnaire to explore the quality of life as well as conversation analytic reconstructions of the "real" communication processes during outpatient clinic which were tape-recorded. Results of the interviews with parents and personnel demonstrate the great relevance of the quality of the relationship in the providing of clinical care; equally important is that the relationship between parents and clinic staff is shaped in a reciprocal fashion. Discrepancies in the perceptions of parents and personnel indicate individual reality constructions. It is desirable that parents and personnel construct a shared reality during their interaction. With respect to this end, the emotional resources of personnel should be regarded as competences and drawn upon more systematically. The parents' role as "experts" should be validated and their active participation in the construction of the communicative situation - which is normally determined by the institution - should be encouraged.

Upper limb motor function in young adults with spina bifida and hydrocephalus

PubMed Central

Salman, M. S.; Jewell, D.; Hetherington, R.; Spiegler, B. J.; MacGregor, D. L.; Drake, J. M.; Humphreys, R. P.; Gentili, F.

2011-01-01

Objective The objective of the study was to measure upper limb motor function in young adults with spina bifida meningomyelocele (SBM) and typically developing age peers. Method Participants were 26 young adults with SBM, with a Verbal or Performance IQ score of at least 70 on the Wechsler scales, and 27 age- and gender-matched controls. Four upper limb motor function tasks were performed under four different visual and cognitive challenge conditions. Motor independence was assessed by questionnaire. Results Fewer SBM than control participants obtained perfect posture and rebound scores. The SBM group performed less accurately and was more disrupted by cognitive challenge than controls on limb dysmetria tasks. The SBM group was slower than controls on the diadochokinesis task. Adaptive motor independence was related to one upper limb motor task, arm posture, and upper rather than lower spinal lesions were associated with less motor independence. Conclusions Young adults with SBM have significant limitations in upper limb function and are more disrupted by some challenges while performing upper limb motor tasks. Within the group of young adults with SBM, upper spinal lesions compromise motor independence more than lower spinal lesions. PMID:19672605

Sexual identity and orientation in adult men and women with spina bifida.

PubMed

Szymanski, Konrad M; Hensel, Devon J; Wiener, John S; Whittam, Benjamin; Cain, Mark P; Misseri, Rosalia

2017-12-11

Sexuality has received little attention in spina bifida (SB) care. The aim of this study was to assess sexual identity and orientation in adults with SB. An international online survey to adults with SB was administered over 10-months (recruitment: SB clinics, SB organizations via social media). Collected data included demographics, sexual identity and orientation. Non-parametric tests were used for analysis. Median age of 77 men and 119 women was 35 years old (52.0% shunted, 48.5% community ambulators, 42.3% outside United States). Most commonly, men identified as male (96.1%), while 1.3% each described themselves as female, transgender and other. All women reporting sexual identity identified as female (99.2%), 0.8% not providing an answer. Most men reported heterosexual orientation (89.6%), followed by gay (7.8%) and bisexual (2.6%). Most women reported heterosexual orientation (84.9%), followed by bisexual (10.4%), gay/lesbian (2.5%), asexual (0.8%) and other (1.7%). As in the general population, sexual identity typically coincides with biological gender. Sexual orientation of adults with SB mirrors the general population. Due to self-selection, these findings likely do not reflect exact prevalence in the SB population.

Successful emergency pain control for posterior rib fractures with ultrasound-guided erector spinae plane block.

PubMed

Luftig, Josh; Mantuani, Daniel; Herring, Andrew A; Dixon, Brittany; Clattenburg, Eben; Nagdev, Arun

2017-12-28

The Eastern Association for the Surgery of Trauma and Trauma Anesthesiology Society Guidelines recommend prompt and effective multimodal analgesia for rib fractures that combines regional anesthesia (RA) techniques with pharmacotherapy to treat pain, optimize pulmonary function, and reduce opioid related complications. However, RA techniques such as epidurals and paravertebral blocks, are generally underutilized or unavailable for emergency department (ED) patients. The recently described serratus anterior plane block (SAPB) is a promising technique, but failures with posterior rib fractures have been observed. The erector spinae plane block (ESPB) is conceptually similar to the SAPB, but targets the posterior thorax making it likely more effective for ED patients with posterior rib fractures. Our initial experience demonstrates consistent success with the ESPB for traumatic posterior rib fracture analgesia. Herein, we present the first description of the ESPB utilized in the ED. Copyright © 2017 Elsevier Inc. All rights reserved.

Characterizing Pelvic Organ Prolapse in Adult Spina Bifida Patients.

PubMed

Liu, Joceline S; Vo, Amanda X; Doolittle, Johnathan; Hamoui, Nabeel; Lewicky-Gaupp, Christina; Kielb, Stephanie J

2016-11-01

To report the distribution of pelvic organ prolapse (POP) stages in adult spina bifida (SB) patients. The severity of POP in the SB population has not been previously reported. Retrospective review of SB patients ≥18 years with a documented POP quantification examination between 2006 and 2014 were included. Patient demographics, gestation, parity, POP quantification examinations and prolapse symptoms were obtained. Thirty-three SB patients were identified with a mean age of 33.2 years. Five patients (15.2%) had stage 0 prolapse, 12 (36.4%) had stage 1, 12 (36.4%) had stage 2, 3 (9.1%) had stage 3, and 1 (3.0%) had stage 4. Of the 16 patients with advanced POP (stage 2 prolapse or greater), only 6 patients (37.5%) reported symptoms related to POP. All 6 symptomatic patients endorsed sensation of a vaginal bulge. Two of the 6 patients also reported dyspareunia. Additionally, 1 patient with advanced POP presented with vaginal bulge, noted by a caregiver, and cervical bleeding, but was otherwise asymptomatic. Twenty-four patients (72.7%) were nulliparous, and 12 of the 24 nulliparous patients (50%) demonstrated prolapse. Despite young age and frequent nulliparity, patients with SB are more likely to have POP than the general population. Additionally, the majority of SB patients with prolapse are asymptomatic. Assessment of pelvic organ prolapse should be included in the evaluation of adult SB females due to the low rate of symptoms even in the setting of advanced stage prolapse and potential impact on both urinary and bowel function. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of sexual function in young men with spina bifida and myelomeningocele using the International Index of Erectile Function.

PubMed

Gamé, Xavier; Moscovici, Jacques; Gamé, Laurence; Sarramon, Jean-Pierre; Rischmann, Pascal; Malavaud, Bernard

2006-03-01

To assess sexual function in young men with spina bifida and myelomeningocele. Between November 2003 and February 2004, a cross-sectional study was performed in 55 men older than 18 years of age who had been regularly followed up for myelomeningocele since childhood, between 1961 and 1985, in the Pediatric Internal Surgery Department. The International Index of Erectile Function (IIEF) questionnaire was mailed to each man. The response rate was 72.7%. Of the 40 men who replied, 16 (40%) had had sexual intercourse at least once during the previous month. These were the older men (age 31.9 +/- 5.7 years versus 27.7 +/- 5.5 years, P = 0.027). The IIEF scores for the whole group were erectile function 11.61 +/- 9.44, orgasmic function 3.53 +/- 3.86, sexual desire 6.94 +/- 2.4, intercourse satisfaction 3.7 +/- 4.81, and overall satisfaction 4.7 +/- 3.34. According to the classification of Cappelleri, of the 16 men who had had sexual intercourse during the previous month, 4 had no erectile dysfunction, 3 had mild, 4 mild to moderate, and 5 severe dysfunction. Erectile function was statistically related to the ability to maintain erections (mean IIEF score 4 and 5 for men with no erectile dysfunction versus a mean IIEF score of 4 and 5 for men with erectile dysfunction: 4.75 +/- 0.5 versus 2.00 +/- 1.32, P = 0.011 for IIEF score of 4 and 4.50 +/- 1.5 versus 3 +/- 2, P = 0.040 for IIEF score of 5). Young adult men with spina bifida and myelomeningocele begin sexual activity late. Moreover, 75% have erectile dysfunction that is related to difficulty in maintaining erections.

(U) Introduction to Monte Carlo Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hungerford, Aimee L.

2017-03-20

Monte Carlo methods are very valuable for representing solutions to particle transport problems. Here we describe a “cook book” approach to handling the terms in a transport equation using Monte Carlo methods. Focus is on the mechanics of a numerical Monte Carlo code, rather than the mathematical foundations of the method.

Quantum Gibbs ensemble Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fantoni, Riccardo, E-mail: rfantoni@ts.infn.it; Moroni, Saverio, E-mail: moroni@democritos.it

We present a path integral Monte Carlo method which is the full quantum analogue of the Gibbs ensemble Monte Carlo method of Panagiotopoulos to study the gas-liquid coexistence line of a classical fluid. Unlike previous extensions of Gibbs ensemble Monte Carlo to include quantum effects, our scheme is viable even for systems with strong quantum delocalization in the degenerate regime of temperature. This is demonstrated by an illustrative application to the gas-superfluid transition of {sup 4}He in two dimensions.

Percutaneous fetoscopic closure of large open spina bifida using a bilaminar skin substitute.

PubMed

Lapa Pedreira, Denise A; Acacio, Gregório L; Gonçalves, Rodrigo T; Sá, Renato Augusto M; Brandt, Reynaldo A; Chmait, Ramen; Kontopoulos, Eftichia; Quintero, Ruben A

2018-01-04

We have previously described our percutaneous fetoscopic technique for the treatment of open spina bifida (OSB). However, approximately 20-30% of OSB defects are too large to allow primary skin closure. We hereby describe a modification of our standard technique using a bilaminar skin substitute to allow closure of such large spinal defects. The aim of this study was to report our clinical experience with the use of a bilaminar skin substitute and a percutaneous fetoscopic technique for the prenatal closure of large spina bifida defects. Surgeries were performed between 24.0 and 28.9 gestational weeks under general anesthesia, using an entirely percutaneous fetoscopic approach with partial CO2 insufflation of the uterine cavity, as previously described. If there was enough skin to be sutured in the midline, only a biocellulose patch was placed over the placode. In cases where skin approximation was not possible, a bilaminar skin substitute (two layers: one silicone and one dermal matrix) was placed over the biocellulose. The surgical site was assessed at birth, and long-term follow-up was performed. Forty-seven consecutive fetuses underwent percutaneous fetoscopic OSB repair. Premature preterm rupture of membranes (PPROM) occurred in 38 (84%), and the mean gestational age at delivery was 32,8 + 2.5 weeks. A bilaminar skin substitute was required in 13 (29%), of which 5 was associated with myeloschisis. In all cases the skin substitute was found at the surgical site, at birth. In 3 (15%) of these cases, postnatal additional repair was needed. In the other 10 cases, the silicone layer detached spontaneously from the dermal matrix (average 25 days after birth), and the lesion healed by secondary-intention. Operating time was significantly longer in cases requiring the bilaminar skin substitute (additional 42 minutes). The subgroup with bilaminar skin substitute had similar PPROM rate and delivery gestational age compared to the one patch group. Complete reversal of

Fetoscopic single-layer repair of open spina bifida using a cellulose patch: preliminary clinical experience.

PubMed

Pedreira, Denise A L; Zanon, Nelci; de Sá, Renato A M; Acacio, Gregório L; Ogeda, Edilson; Belem, Teresa M L O U; Chmait, Ramen H; Kontopoulos, Eftichia; Quintero, Ruben A

2014-11-01

To report our preliminary clinical experience in the antenatal correction of open spina bifida (OSB) using a fetoscopic approach and a simplified closure technique. Four fetuses with lumbar-sacral defects were operated in utero from 25 to 27 weeks. Surgeries were performed percutaneously under general anesthesia using three trocars and partial carbon dioxide insufflation. After dissection of the neural placode, the surrounding skin was closed over a cellulose patch using a single continuous stitch. Surgical closure was successful in three of the four cases. All successful cases showed improvement of the hindbrain herniation and no neonatal neurosurgical repair was required in two cases. Delivery occurred between 31 and 33 weeks, and no fetal or neonatal deaths occurred. Ventriculoperitoneal shunting was not needed in two out of the 3 successful cases. Our preliminary experience suggests that definitive fetoscopic repair of OSB is feasible using our innovative surgical technique. A phase I trial for the fetoscopic correction of OSB with this technique is currently being conducted.

Neuromuscular training based on whole body vibration in children with spina bifida: a retrospective analysis of a new physiotherapy treatment program.

PubMed

Stark, C; Hoyer-Kuhn, H-K; Semler, O; Hoebing, L; Duran, I; Cremer, R; Schoenau, E

2015-02-01

Spina bifida is the most common congenital cause of spinal cord lesions resulting in paralysis and secondary conditions like osteoporosis due to immobilization. Physiotherapy is performed for optimizing muscle function and prevention of secondary conditions. Therefore, training of the musculoskeletal system is one of the major aims in the rehabilitation of children with spinal cord lesions. The neuromuscular physiotherapy treatment program Auf die Beine combines 6 months of home-based whole body vibration (WBV) with interval blocks at the rehabilitation center: 13 days of intensive therapy at the beginning and 6 days after 3 months. Measurements are taken at the beginning (M0), after 6 months of training (M6), and after a 6-month follow-up period (M12). Gait parameters are assessed by ground reaction force and motor function by the Gross Motor Function Measurement (GMFM-66). Sixty children (mean age 8.71 ± 4.7 years) who participated in the program until February 2014 were retrospectively analyzed. Walking velocity improved significantly by 0.11 m/s (p = 0.0026) and mobility (GMFM-66) by 2.54 points (p = 0.001) after the training. All changes at follow-up were not significant, but significant changes were observed after the training period. Decreased contractures were observed with increased muscle function. Significant improvements in motor function were observed after the active training period of the new neuromuscular training concept. This first analysis of the new neuromuscular rehabilitation concept Auf die Beine showed encouraging results for a safe and efficient physiotherapy treatment program which increases motor function in children with spina bifida.

Attention lapses in children with spina bifida and hydrocephalus and children with attention-deficit/hyperactivity disorder.

PubMed

De la Torre, Gabriel G; Martin, Alba; Cervantes, Elizabeth; Guil, Rocio; Mestre, Jose M

2017-08-01

Attentional lapses are usually defined as temporary and often brief shifts of attention away from some primary task to unrelated internal information processing. This study addressed the incidence of attention lapses and differences in attentional functioning in 30 children with attention-deficit/hyperactivity disorder (ADHD), 26 healthy children, and 29 children with spina bifida myelomeningocele and hydrocephalus (SBH). Assessments were conducted using computerized tonic and phasic attention tests, the Symbol Digit Modalities Test (SDMT), and the Trail Making Test Form B (TMT-B). The group with SBH differed from normal controls on cognitive measures of attention and executive functions. The ADHD group obtained lower scores than the SBH group and healthy children. ANOVA results showed that there was an effect of shunt revisions and shunt-related infections on neuropsychological performance. Lapses of attention together with reaction time may thus represent important factors for the understanding of cognitive deficits in SBH.

The effects of orthoses, footwear, and walking aids on the walking ability of children and adolescents with spina bifida: A systematic review using International Classification of Functioning, Disability and Health for Children and Youth (ICF-CY) as a reference framework.

PubMed

Ivanyi, Barbara; Schoenmakers, Marja; van Veen, Natasja; Maathuis, Karel; Nollet, Frans; Nederhand, Marc

2015-12-01

To date no review has been published that analyzes the efficacy of assistive devices on the walking ability of ambulant children and adolescents with spina bifida and, differentiates between the effects of treatment on gait parameters, walking capacity, and walking performance. To review the literature for evidence of the efficacy of orthotic management, footwear, and walking aids on gait and walking outcomes in ambulant children and adolescents with spina bifida. Systematic literature review. A systematic literature search was performed to identify studies that evaluated the effect of any type of lower limb orthoses, orthopedic footwear, or walking aids in ambulant children (≤18 years old) with spina bifida. Outcome measures and treatment results for gait parameters, walking capacity, and walking performance were identified using International Classification of Functioning, Disability and Health for Children and Youth (ICF-CY) as the reference framework. Six case-crossover studies met the criteria and were included in this systematic review. Four studies provided indications of the efficacy of the ankle-foot orthosis in improving a number of kinematic and kinetic properties of gait, stride characteristics, and the oxygen cost of walking. Two studies indicated that walking with forearm crutches may have a favorable effect on gait. The evidence level of these studies was low, and none of the studies assessed the efficacy of the intervention on walking capacity and walking performance. Some data support the efficacy of using ankle-foot orthosis and crutches for gait and walking outcomes at the body functions and structures level of the ICF-CY. Potential benefits at the activities and participation level have not been investigated. This is the first evidence-based systematic review of the efficacy of assistive devices for gait and walking outcomes for children with spina bifida. The ICF-CY is used as a reference framework to differentiate the effects of treatment

Executive functions in adolescents with spina bifida: relations with autonomy development and parental intrusiveness.

PubMed

Tuminello, Elizabeth R; Holmbeck, Grayson N; Olson, Rick

2012-01-01

The current study was part of a larger longitudinal investigation and examined the relation of parent-report and performance measures of executive functioning (EF) with measures of behavioral and emotional autonomy and parental intrusiveness in adolescents with and without spina bifida (SB; n=65 in a comparison sample and 61 in an SB sample; M age=14.55, SD=0.63). For both groups, higher levels of parent-reported EF problems predicted higher levels of observed child dependency and lower levels of teacher-reported intrinsic motivation. Higher scores on performance EF measures predicted lower levels of observed child dependency and observed maternal intrusiveness for both groups. In adolescents with SB only, higher performance EF scores predicted higher intrinsic motivation and emotional autonomy from both mother and father and predicted lower levels of observed paternal intrusiveness. While causal conclusions cannot be drawn, EFs appear to be closely related to autonomy development and parental intrusiveness, particularly for adolescents with SB. These results suggest that the inclusion of EF training in interventions targeting adolescents with SB may be beneficial for autonomy development.

The 14.6 kd rubber elongation factor (Hev b 1) and 24 kd (Hev b 3) rubber particle proteins are recognized by IgE from patients with spina bifida and latex allergy.

PubMed

Yeang, H Y; Cheong, K F; Sunderasan, E; Hamzah, S; Chew, N P; Hamid, S; Hamilton, R G; Cardosa, M J

1996-09-01

Two major water-insoluble proteins are located on the surface of rubber particles in Hevea brasiliensis latex. A 14.6 kd protein (Hev b 1), found mainly on large rubber particles (> 350 mm in diameter), and a 24 kd protein (Hev b 3), found mainly on small rubber particles (average diameter, 70 nm), are recognized by IgE from patients with spina bifida and latex allergy. Although Hev b 1 (also called the rubber elongation factor [REF]) has previously been reported as a major latex allergen, this conclusion has been disputed on the basis of results from other studies. The allergenicity of Hev b 1 is verified in this study by testing the recombinant protein generated from its gene. Because allergenicity is confined to patients with spina bifida and not observed in adults sensitive to latex, it is not a major latex allergen. The identification of Hev b 3 as another allergen originating from rubber particles is confirmed by immunogold labeling and electron microscopy. Observations with the monoclonal antibody USM/RC2 developed against Hev b 3 show that the protein has a tendency to fragment into several polypeptides of lower molecular weight (from 24 kd to about 5 kd) when stored at -20 degrees C. There is also indication of protein aggregation from the appearance of proteins with molecular weights greater than 24 kd. Fragmentation of Hev b 3 is induced immediately on he addition of latex B-serum, which is normally compartmentalized in the lutoids in fresh latex. In the preparation of ammoniated latex (used for the manufacture of latex products), the lutoids are ruptured, and the released B-serum reacts with Hev b 3 on the rubber particles to give rise to an array of low molecular weight polypeptides that are allergenic to patients with spina bifida.

Zizyphus spina-christi protects against carbon tetrachloride-induced liver fibrosis in rats.

PubMed

Amin, Amr; Mahmoud-Ghoneim, Doaa

2009-08-01

The study of chronic hepatic fibrosis has been receiving an escalating attention in the past two decades. The aim of the study was to examine the effects of the water extract of Zizyphus spina-christi (L.) (ZSC) on carbon tetrachloride (CCl(4))-induced hepatic fibrosis. ZSC extract was daily administered [alone (ZSC-control group) or along with CCl(4) (protected groups)] at 0.125 (low dose), 0.250 (medium dose) and 0.350 (high dose) g/kg b.wt. for 8 weeks. Histo-pathological, biochemical and histology texture analyses revealed that ZSC significantly impede the progression of hepatic fibrosis. ZSC resulted in a significant amelioration of liver injury judged by the reduced activities of serum ALT and AST. Oral administration of ZSC has also restored normal levels of malondialdehyde and retained control activities of endogenous antioxidants such as SOD, CAT and GSH. Furthermore, ZSC reduced the expression of alpha-smooth muscle actin, the deposition of types I and III collagen in CCl(4)-injured rats. Texture analysis of microscopic images along with fibrosis index calculation showed improvement in the quality of type I collagen distribution and its quantity after administration of ZSC extract. These results demonstrate that administration of ZSC may be useful in the treatment and prevention of hepatic fibrosis.

Parent perceptions of health promotion for school-age children with spina bifida.

PubMed

Luther, Brenda L; Christian, Becky J

2017-01-01

To gain insight into how parents develop their beliefs of health promotion for their children with spina bifida (SB) and how they develop and promote health promotion practices for their children. Qualitative, exploratory design with semi-structured interviews of parents of children between 6 and 12 years of age diagnosed with SB was used for this study. Perceptions of health promotion were maintaining healthy bowel function and managing SB care. Good bowel function and SB management is health promotion and adequate bowel function is viewed as a marker of health. Maintaining healthy bowel function was identified by parents as the key marker of health for their children with SB. Further, the term health promotion brought up plans, concerns, and goals more related to their child's physiologic functioning and health care needs rather than promoting health and avoiding preventable disease. Nurses and healthcare providers are in unique and powerful positions for strategizing with parents on how to integrate health promotion into the lives of children with SB. Team-based, whole-person, holistic assessment and teaching inclusive of promoting healthy lifestyle behaviors in addition to providing excellent care related to their physiologic systems affected by SB can improve how we promote health for these children. © 2017 Wiley Periodicals, Inc.

Monte Carlo Simulation for Perusal and Practice.

ERIC Educational Resources Information Center

Brooks, Gordon P.; Barcikowski, Robert S.; Robey, Randall R.

The meaningful investigation of many problems in statistics can be solved through Monte Carlo methods. Monte Carlo studies can help solve problems that are mathematically intractable through the analysis of random samples from populations whose characteristics are known to the researcher. Using Monte Carlo simulation, the values of a statistic are…

A girl with spina bifida, an extra leg, and ectopic intestinal loops--a "foetus in foetu" or a whim of the neural crest?

PubMed

Lende, G; Wendemu, W; Mørk, S; Wester, K

2007-10-01

This article describes a girl with an extra leg attached to her lower back, combined with a spina bifida and a myelomeningocele. Despite lacking sensory or motor functions, the leg grew proportionately with the rest of the body. The bony structures were almost normal. A cross section showed fat tissue with some centrally situated blood vessels, nerve bundles, and muscular fragments. Proximally, an isolated colon loop was found. The extra leg and intestine respected the dorsal fascia, without connection with the peritoneal or retroperitoneal compartments. The finding is discussed with reference to existing hypotheses for limb formation.

The assessment of weight status in children and young people attending a spina bifida outpatient clinic: a retrospective medical record review

PubMed Central

Swift, Judy Anne; Yung, Emily; Lyons, Julia; Church, Paige

2013-01-01

Purpose Children with disabilities are two to three times more likely to become overweight or obese than typically developing children. Children with spina bifida (SB) are at particular risk, yet obesity prevalence and weight management with this population are under-researched. This retrospective chart review explored how weight is assessed and discussed in a children’s SB outpatient clinic. Method Height/weight data were extracted from records of children aged 2–18 with a diagnosis of SB attending an outpatient clinic at least once between June 2009–2011. Body mass index was calculated and classified using Centers for Disease Control and Prevention cut-offs. Notes around weight, diet and physical/sedentary activities were transcribed verbatim and analysed using descriptive thematic analysis. Results Of 180 eligible patients identified, only 63 records had sufficient data to calculate BMI; 15 patients were overweight (23.81%) and 11 obese (17.46%). Weight and physical activity discussions were typically related to function (e.g. mobility, pain). Diet discussions focused on bowel and bladder function and dietary challenges. Conclusions Anthropometrics were infrequently recorded, leaving an incomplete picture of weight status in children with SB and suggesting that weight is not prioritised. Bowel/bladder function was highlighted over other benefits of a healthy body weight, indicating that health promotion opportunities are being missed. Implications for Rehabilitation It is important to assess, categorise and record anthropometric data for children and youth with spina bifida as they may be at particular risk of excess weight. Information around weight categorisation should be discussed openly and non-judgmentally with children and their families. Health promotion opportunities may be missed by focusing solely on symptom management or function. Healthcare professionals should emphasise the broad benefits of healthy eating and physical activity, offering

The assessment of weight status in children and young people attending a spina bifida outpatient clinic: a retrospective medical record review.

PubMed

McPherson, Amy C; Swift, Judy Anne; Yung, Emily; Lyons, Julia; Church, Paige

2013-01-01

Children with disabilities are two to three times more likely to become overweight or obese than typically developing children. Children with spina bifida (SB) are at particular risk, yet obesity prevalence and weight management with this population are under-researched. This retrospective chart review explored how weight is assessed and discussed in a children's SB outpatient clinic. Height/weight data were extracted from records of children aged 2-18 with a diagnosis of SB attending an outpatient clinic at least once between June 2009-2011. Body mass index was calculated and classified using Centers for Disease Control and Prevention cut-offs. Notes around weight, diet and physical/sedentary activities were transcribed verbatim and analysed using descriptive thematic analysis. Of 180 eligible patients identified, only 63 records had sufficient data to calculate BMI; 15 patients were overweight (23.81%) and 11 obese (17.46%). Weight and physical activity discussions were typically related to function (e.g. mobility, pain). Diet discussions focused on bowel and bladder function and dietary challenges. Anthropometrics were infrequently recorded, leaving an incomplete picture of weight status in children with SB and suggesting that weight is not prioritised. Bowel/bladder function was highlighted over other benefits of a healthy body weight, indicating that health promotion opportunities are being missed. Implications for Rehabilitation It is important to assess, categorise and record anthropometric data for children and youth with spina bifida as they may be at particular risk of excess weight. Information around weight categorisation should be discussed openly and non-judgmentally with children and their families. Health promotion opportunities may be missed by focusing solely on symptom management or function. Healthcare professionals should emphasise the broad benefits of healthy eating and physical activity, offering strategies to enable the child to incorporate

Risk of spina bifida and maternal cigarette, alcohol, and coffee use during the first month of pregnancy.

PubMed

Benedum, Corey M; Yazdy, Mahsa M; Mitchell, Allen A; Werler, Martha M

2013-08-02

This study was conducted to assess the association between the risks of spina bifida (SB) in relation to cigarette, alcohol, and caffeine consumption by women during the first month of pregnancy. Between 1988-2012, this multi-center case-control study interviewed mothers of 776 SB cases and 8,756 controls about pregnancy events and exposures. We evaluated cigarette smoking, frequency of alcohol drinking, and caffeine intake during the first lunar month of pregnancy in relation to SB risk. Logistic regression models were used to calculate adjusted odds ratios and 95% confidence intervals. Levels of cigarette smoking (1-9 and ≥10/day), alcohol intake (average ≥4 drinks/day) and caffeine intake (<1, 1, and ≥2 cups/day) were not likely to be associated with increased risk of SB. Further, results were similar among women who ingested less than the recommended amount of folic acid (400 μg/day).

Self-learning Monte Carlo method

DOE PAGES

Liu, Junwei; Qi, Yang; Meng, Zi Yang; ...

2017-01-04

Monte Carlo simulation is an unbiased numerical tool for studying classical and quantum many-body systems. One of its bottlenecks is the lack of a general and efficient update algorithm for large size systems close to the phase transition, for which local updates perform badly. In this Rapid Communication, we propose a general-purpose Monte Carlo method, dubbed self-learning Monte Carlo (SLMC), in which an efficient update algorithm is first learned from the training data generated in trial simulations and then used to speed up the actual simulation. Lastly, we demonstrate the efficiency of SLMC in a spin model at the phasemore » transition point, achieving a 10–20 times speedup.« less

Bayesian statistics and Monte Carlo methods

NASA Astrophysics Data System (ADS)

Koch, K. R.

2018-03-01

The Bayesian approach allows an intuitive way to derive the methods of statistics. Probability is defined as a measure of the plausibility of statements or propositions. Three rules are sufficient to obtain the laws of probability. If the statements refer to the numerical values of variables, the so-called random variables, univariate and multivariate distributions follow. They lead to the point estimation by which unknown quantities, i.e. unknown parameters, are computed from measurements. The unknown parameters are random variables, they are fixed quantities in traditional statistics which is not founded on Bayes' theorem. Bayesian statistics therefore recommends itself for Monte Carlo methods, which generate random variates from given distributions. Monte Carlo methods, of course, can also be applied in traditional statistics. The unknown parameters, are introduced as functions of the measurements, and the Monte Carlo methods give the covariance matrix and the expectation of these functions. A confidence region is derived where the unknown parameters are situated with a given probability. Following a method of traditional statistics, hypotheses are tested by determining whether a value for an unknown parameter lies inside or outside the confidence region. The error propagation of a random vector by the Monte Carlo methods is presented as an application. If the random vector results from a nonlinearly transformed vector, its covariance matrix and its expectation follow from the Monte Carlo estimate. This saves a considerable amount of derivatives to be computed, and errors of the linearization are avoided. The Monte Carlo method is therefore efficient. If the functions of the measurements are given by a sum of two or more random vectors with different multivariate distributions, the resulting distribution is generally not known. TheMonte Carlo methods are then needed to obtain the covariance matrix and the expectation of the sum.

Prenatal Ablation of Nicotinic Receptor alpha7 Cell Lineages Produces Lumbosacral Spina Bifida the Severity of Which is Modified by Choline and Nicotine Exposure

PubMed Central

Rogers, Scott W; Tvrdik, Petr; Capecchi, Mario R; Gahring, Lorise C

2012-01-01

Lumbosacral spina bifida is a common debilitating birth defect whose multiple causes are poorly understood. Here, we provide the first genetic delineation of cholinergic nicotinic receptor alpha7 (Chrna7) expression and link the ablation of the Chrna7 cell lineage to this condition in the mouse. Using homologous recombination, an IRES-Cre bi-cistronic cassette was introduced into the 3′ noncoding region of Chrna7 (Chrna7:Cre) for identifying cell lineages expressing this gene. This lineage first appears at embryonic day E9.0 in rhombomeres 3 and 5 of the neural tube and extends to cell subsets in most tissues by E14.5. Ablation of the Chrna7:Cre cell lineage in embryos from crosses with conditionally expressed attenuated diphtheria toxin results in precise developmental defects including omphalocele (89%) and open spina bifida (SB; 80%). We hypothesized that like humans, this defect would be modified by environmental compounds not only folic acid or choline but also nicotine. Prenatal chronic oral nicotine administration substantially worsened the defect to often include the rostral neural tube. In contrast, supplementation of the maternal diet with 2% choline decreased SB prevalence to 38% and dramatically reduced the defect severity. Folic acid supplementation only trended towards a reduced SB frequency. The omphalocele was unaffected by these interventions. These studies identify the Chrna7 cell lineage as participating in posterior neuropore closure and present a novel model of lower SB that can be substantially modified by the prenatal environment. © 2012 Wiley Periodicals, Inc. PMID:22473653

Long-term complications following bladder augmentations in patients with spina bifida: bladder calculi, perforation of the augmented bladder and upper tract deterioration.

PubMed

Husmann, Douglas A

2016-02-01

We desire to review our experience with bladder augmentation in spina bifida patients followed in a transitional and adult urologic practice. This paper will specifically focus on three major complications: bladder calculi, the most frequent complication found following bladder augmentation, perforation of the augmentation, its most lethal complication and finally we will address loss of renal function as a direct result of our surgical reconstructive procedures. We reviewed a prospective data base maintained on patients with spina bifida followed in our transitional and adult urology clinic from 1986 to date. Specific attention was given to patients who had developed bladder calculi, sustained a spontaneous perforation of the augmented bladder or had developed new onset of renal scarring or renal insufficiency (≥ stage 3 renal failure) during prolonged follow-up. The development of renal stones (P<0.05) and symptomatic urinary tract infections (P<0.0001) were found to be significantly reduced by the use of high volume (≥240 mL) daily bladder wash outs. Individuals who still developed bladder calculi recalcitrant to high volume wash outs were not benefited by the correction of underlying metabolic abnormalities or mucolytic agents. Spontaneous bladder perforations in the adult patient population with spina bifida were found to be directly correlated to substance abuse and noncompliance with intermittent catheterization, P<0.005. Deterioration of the upper tracts as defined by the new onset of renal scars occurred in 40% (32/80) of the patients managed by a ileocystoplasty and simultaneous bladder neck outlet procedure during a median follow-up interval 14 years (range, 8-45 years). Development of ≥ stage 3 chronic renal failure occurred within 38% (12/32) of the patients with scarring i.e., 15% (12/80) of the total patient population. Prior to the development of the renal scarring, 69% (22/32) of the patients had been noncompliant with intermittent

Long-term complications following bladder augmentations in patients with spina bifida: bladder calculi, perforation of the augmented bladder and upper tract deterioration

PubMed Central

2016-01-01

Background We desire to review our experience with bladder augmentation in spina bifida patients followed in a transitional and adult urologic practice. This paper will specifically focus on three major complications: bladder calculi, the most frequent complication found following bladder augmentation, perforation of the augmentation, its most lethal complication and finally we will address loss of renal function as a direct result of our surgical reconstructive procedures. Methods We reviewed a prospective data base maintained on patients with spina bifida followed in our transitional and adult urology clinic from 1986 to date. Specific attention was given to patients who had developed bladder calculi, sustained a spontaneous perforation of the augmented bladder or had developed new onset of renal scarring or renal insufficiency (≥ stage 3 renal failure) during prolonged follow-up. Results The development of renal stones (P<0.05) and symptomatic urinary tract infections (P<0.0001) were found to be significantly reduced by the use of high volume (≥240 mL) daily bladder wash outs. Individuals who still developed bladder calculi recalcitrant to high volume wash outs were not benefited by the correction of underlying metabolic abnormalities or mucolytic agents. Spontaneous bladder perforations in the adult patient population with spina bifida were found to be directly correlated to substance abuse and noncompliance with intermittent catheterization, P<0.005. Deterioration of the upper tracts as defined by the new onset of renal scars occurred in 40% (32/80) of the patients managed by a ileocystoplasty and simultaneous bladder neck outlet procedure during a median follow-up interval 14 years (range, 8–45 years). Development of ≥ stage 3 chronic renal failure occurred within 38% (12/32) of the patients with scarring i.e., 15% (12/80) of the total patient population. Prior to the development of the renal scarring, 69% (22/32) of the patients had been noncompliant

Social Skills in Youth With Spina Bifida: A Longitudinal Multimethod Investigation Comparing Biopsychosocial Predictors.

PubMed

Holbein, Christina E; Peugh, James L; Holmbeck, Grayson N

2017-11-01

To examine the relative contributions of neuropsychological (attention and executive function), family (cohesion and conflict), and health (body mass index, lesion level, gross motor function) domains on social skills over time in youth with spina bifida (SB). In all, 140 youth with SB (T1 mean age = 11.43 years) and their families participated in the study at baseline with an additional visit 2 years later. Study variables were assessed with multiple methods (questionnaire, medical chart review, observation, neuropsychological tests) and reporters (parents, teachers). Multivariate hierarchical linear regressions determined the predictive power of the three domains for T2 social skills. Neuropsychological variables accounted for significant variance in mother- and father-reported T2 social skills. Neither family nor health variables contributed significantly to later social skills when other domains were included in the model. Neuropsychological factors are particularly important for social skill development in youth with SB. Findings can inform screening and intervention practices. © The Author 2017. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Neutrino oscillation parameter sampling with MonteCUBES

NASA Astrophysics Data System (ADS)

Blennow, Mattias; Fernandez-Martinez, Enrique

2010-01-01

We present MonteCUBES ("Monte Carlo Utility Based Experiment Simulator"), a software package designed to sample the neutrino oscillation parameter space through Markov Chain Monte Carlo algorithms. MonteCUBES makes use of the GLoBES software so that the existing experiment definitions for GLoBES, describing long baseline and reactor experiments, can be used with MonteCUBES. MonteCUBES consists of two main parts: The first is a C library, written as a plug-in for GLoBES, implementing the Markov Chain Monte Carlo algorithm to sample the parameter space. The second part is a user-friendly graphical Matlab interface to easily read, analyze, plot and export the results of the parameter space sampling. Program summaryProgram title: MonteCUBES (Monte Carlo Utility Based Experiment Simulator) Catalogue identifier: AEFJ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFJ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public Licence No. of lines in distributed program, including test data, etc.: 69 634 No. of bytes in distributed program, including test data, etc.: 3 980 776 Distribution format: tar.gz Programming language: C Computer: MonteCUBES builds and installs on 32 bit and 64 bit Linux systems where GLoBES is installed Operating system: 32 bit and 64 bit Linux RAM: Typically a few MBs Classification: 11.1 External routines: GLoBES [1,2] and routines/libraries used by GLoBES Subprograms used:Cat Id ADZI_v1_0, Title GLoBES, Reference CPC 177 (2007) 439 Nature of problem: Since neutrino masses do not appear in the standard model of particle physics, many models of neutrino masses also induce other types of new physics, which could affect the outcome of neutrino oscillation experiments. In general, these new physics imply high-dimensional parameter spaces that are difficult to explore using classical methods such as multi-dimensional projections and minimizations, such as those

Formate supplementation enhances folate-dependent nucleotide biosynthesis and prevents spina bifida in a mouse model of folic acid-resistant neural tube defects.

PubMed

Sudiwala, Sonia; De Castro, Sandra C P; Leung, Kit-Yi; Brosnan, John T; Brosnan, Margaret E; Mills, Kevin; Copp, Andrew J; Greene, Nicholas D E

2016-07-01

The curly tail mouse provides a model for neural tube defects (spina bifida and exencephaly) that are resistant to prevention by folic acid. The major ct gene, responsible for spina bifida, corresponds to a hypomorphic allele of grainyhead-like 3 (Grhl3) but the frequency of NTDs is strongly influenced by modifiers in the genetic background. Moreover, exencephaly in the curly tail strain is not prevented by reinstatement of Grhl3 expression. In the current study we found that expression of Mthfd1L, encoding a key component of mitochondrial folate one-carbon metabolism (FOCM), is significantly reduced in ct/ct embryos compared to a partially congenic wild-type strain. This expression change is not attributable to regulation by Grhl3 or the genetic background at the Mthfd1L locus. Mitochondrial FOCM provides one-carbon units as formate for FOCM reactions in the cytosol. We found that maternal supplementation with formate prevented NTDs in curly tail embryos and also resulted in increased litter size. Analysis of the folate profile of neurulation-stage embryos showed that formate supplementation resulted in an increased proportion of formyl-THF and THF but a reduction in proportion of 5-methyl THF. In contrast, THF decreased and 5-methyl THF was relatively more abundant in the liver of supplemented dams than in controls. In embryos cultured through the period of spinal neurulation, incorporation of labelled thymidine and adenine into genomic DNA was suppressed by supplemental formate, suggesting that de novo folate-dependent biosynthesis of nucleotides (thymidylate and purines) was enhanced. We hypothesise that reduced Mthfd1L expression may contribute to susceptibility to NTDs in the curly tail strain and that formate acts as a one-carbon donor to prevent NTDs. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Self-Learning Monte Carlo Method

NASA Astrophysics Data System (ADS)

Liu, Junwei; Qi, Yang; Meng, Zi Yang; Fu, Liang

Monte Carlo simulation is an unbiased numerical tool for studying classical and quantum many-body systems. One of its bottlenecks is the lack of general and efficient update algorithm for large size systems close to phase transition or with strong frustrations, for which local updates perform badly. In this work, we propose a new general-purpose Monte Carlo method, dubbed self-learning Monte Carlo (SLMC), in which an efficient update algorithm is first learned from the training data generated in trial simulations and then used to speed up the actual simulation. We demonstrate the efficiency of SLMC in a spin model at the phase transition point, achieving a 10-20 times speedup. This work is supported by the DOE Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0010526.

Recent advances and future prospects for Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Forrest B

2010-01-01

The history of Monte Carlo methods is closely linked to that of computers: The first known Monte Carlo program was written in 1947 for the ENIAC; a pre-release of the first Fortran compiler was used for Monte Carlo In 1957; Monte Carlo codes were adapted to vector computers in the 1980s, clusters and parallel computers in the 1990s, and teraflop systems in the 2000s. Recent advances include hierarchical parallelism, combining threaded calculations on multicore processors with message-passing among different nodes. With the advances In computmg, Monte Carlo codes have evolved with new capabilities and new ways of use. Production codesmore » such as MCNP, MVP, MONK, TRIPOLI and SCALE are now 20-30 years old (or more) and are very rich in advanced featUres. The former 'method of last resort' has now become the first choice for many applications. Calculations are now routinely performed on office computers, not just on supercomputers. Current research and development efforts are investigating the use of Monte Carlo methods on FPGAs. GPUs, and many-core processors. Other far-reaching research is exploring ways to adapt Monte Carlo methods to future exaflop systems that may have 1M or more concurrent computational processes.« less

Monte Carlo Transport for Electron Thermal Transport

NASA Astrophysics Data System (ADS)

Chenhall, Jeffrey; Cao, Duc; Moses, Gregory

2015-11-01

The iSNB (implicit Schurtz Nicolai Busquet multigroup electron thermal transport method of Cao et al. is adapted into a Monte Carlo transport method in order to better model the effects of non-local behavior. The end goal is a hybrid transport-diffusion method that combines Monte Carlo Transport with a discrete diffusion Monte Carlo (DDMC). The hybrid method will combine the efficiency of a diffusion method in short mean free path regions with the accuracy of a transport method in long mean free path regions. The Monte Carlo nature of the approach allows the algorithm to be massively parallelized. Work to date on the method will be presented. This work was supported by Sandia National Laboratory - Albuquerque and the University of Rochester Laboratory for Laser Energetics.

Response Matrix Monte Carlo for electron transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballinger, C.T.; Nielsen, D.E. Jr.; Rathkopf, J.A.

1990-11-01

A Response Matrix Monte Carol (RMMC) method has been developed for solving electron transport problems. This method was born of the need to have a reliable, computationally efficient transport method for low energy electrons (below a few hundred keV) in all materials. Today, condensed history methods are used which reduce the computation time by modeling the combined effect of many collisions but fail at low energy because of the assumptions required to characterize the electron scattering. Analog Monte Carlo simulations are prohibitively expensive since electrons undergo coulombic scattering with little state change after a collision. The RMMC method attempts tomore » combine the accuracy of an analog Monte Carlo simulation with the speed of the condensed history methods. The combined effect of many collisions is modeled, like condensed history, except it is precalculated via an analog Monte Carol simulation. This avoids the scattering kernel assumptions associated with condensed history methods. Results show good agreement between the RMMC method and analog Monte Carlo. 11 refs., 7 figs., 1 tabs.« less

Virtual socialization in adults with spina bifida.

PubMed

Chan, Wendy M; Dicianno, Brad E

2011-03-01

To use spina bifida (SB) as a model of chronic physical disability to study the associations of virtual socialization, friendships, and quality of life (QOL) in adults. Cross-sectional survey. Subjects were recruited from residential living facilities, outpatient clinics, and the University of Pittsburgh Medical Center (UPMC) research registry. Inclusion criteria were age between 18 and 80 years and clinical diagnoses of SB cystica (myelomeningocele) and hydrocephalus. The exclusion criterion was the diagnosis of SB occulta. Sixty-three eligible adults were enrolled, and all completed the study. The survey via questionnaire was performed in person or over the telephone. Data collected included the World Health Organization's Medical Outcomes Study 26-item Short Form, Economic Self-Sufficiency from the Craig Handicap Assessment and Reporting Technique Short Form, virtual socializing habits, and number of friends. Three linear regression models were performed, each with a unique dependent variable: number of friends, psychological QOL, or social QOL. The following independent variables were included in all models: age, gender, ethnicity, economic self-sufficiency, marital status, education level, lesion level, health status, user group, collection method, and time spent virtually socializing. In addition, each regression model included the dependent variables from the other 2 models in its independent variables. Increased degree of virtual socialization (VS) was associated with a greater number of friends (P = .003, r = .684). Mean (standard deviation) numbers of friends by VS groups were the following: users, n = 4.9 ± 2.7; semi-users, n = 3.8 ± 2.7; and nonusers, n = 2.1 ± 2.3, which represent a 2.3 times greater number of friends between the users and nonusers. The effect of virtual socialization on QOL was also positive, however, not statistically significant. People with chronic physical disabilities, such as SB, are at high risk for peer rejection and long

Deterministic theory of Monte Carlo variance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueki, T.; Larsen, E.W.

1996-12-31

The theoretical estimation of variance in Monte Carlo transport simulations, particularly those using variance reduction techniques, is a substantially unsolved problem. In this paper, the authors describe a theory that predicts the variance in a variance reduction method proposed by Dwivedi. Dwivedi`s method combines the exponential transform with angular biasing. The key element of this theory is a new modified transport problem, containing the Monte Carlo weight w as an extra independent variable, which simulates Dwivedi`s Monte Carlo scheme. The (deterministic) solution of this modified transport problem yields an expression for the variance. The authors give computational results that validatemore » this theory.« less

Vectorized Monte Carlo methods for reactor lattice analysis

NASA Technical Reports Server (NTRS)

Brown, F. B.

1984-01-01

Some of the new computational methods and equivalent mathematical representations of physics models used in the MCV code, a vectorized continuous-enery Monte Carlo code for use on the CYBER-205 computer are discussed. While the principal application of MCV is the neutronics analysis of repeating reactor lattices, the new methods used in MCV should be generally useful for vectorizing Monte Carlo for other applications. For background, a brief overview of the vector processing features of the CYBER-205 is included, followed by a discussion of the fundamentals of Monte Carlo vectorization. The physics models used in the MCV vectorized Monte Carlo code are then summarized. The new methods used in scattering analysis are presented along with details of several key, highly specialized computational routines. Finally, speedups relative to CDC-7600 scalar Monte Carlo are discussed.

Monte Carlo Techniques for Nuclear Systems - Theory Lectures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Forrest B.

These are lecture notes for a Monte Carlo class given at the University of New Mexico. The following topics are covered: course information; nuclear eng. review & MC; random numbers and sampling; computational geometry; collision physics; tallies and statistics; eigenvalue calculations I; eigenvalue calculations II; eigenvalue calculations III; variance reduction; parallel Monte Carlo; parameter studies; fission matrix and higher eigenmodes; doppler broadening; Monte Carlo depletion; HTGR modeling; coupled MC and T/H calculations; fission energy deposition. Solving particle transport problems with the Monte Carlo method is simple - just simulate the particle behavior. The devil is in the details, however. Thesemore » lectures provide a balanced approach to the theory and practice of Monte Carlo simulation codes. The first lectures provide an overview of Monte Carlo simulation methods, covering the transport equation, random sampling, computational geometry, collision physics, and statistics. The next lectures focus on the state-of-the-art in Monte Carlo criticality simulations, covering the theory of eigenvalue calculations, convergence analysis, dominance ratio calculations, bias in Keff and tallies, bias in uncertainties, a case study of a realistic calculation, and Wielandt acceleration techniques. The remaining lectures cover advanced topics, including HTGR modeling and stochastic geometry, temperature dependence, fission energy deposition, depletion calculations, parallel calculations, and parameter studies. This portion of the class focuses on using MCNP to perform criticality calculations for reactor physics and criticality safety applications. It is an intermediate level class, intended for those with at least some familiarity with MCNP. Class examples provide hands-on experience at running the code, plotting both geometry and results, and understanding the code output. The class includes lectures & hands-on computer use for a variety of Monte Carlo

Random Numbers and Monte Carlo Methods

NASA Astrophysics Data System (ADS)

Scherer, Philipp O. J.

Many-body problems often involve the calculation of integrals of very high dimension which cannot be treated by standard methods. For the calculation of thermodynamic averages Monte Carlo methods are very useful which sample the integration volume at randomly chosen points. After summarizing some basic statistics, we discuss algorithms for the generation of pseudo-random numbers with given probability distribution which are essential for all Monte Carlo methods. We show how the efficiency of Monte Carlo integration can be improved by sampling preferentially the important configurations. Finally the famous Metropolis algorithm is applied to classical many-particle systems. Computer experiments visualize the central limit theorem and apply the Metropolis method to the traveling salesman problem.

Relations between Brain Structure and Attentional Function in Spina Bifida: Utilization of Robust Statistical Approaches

PubMed Central

Kulesz, Paulina A.; Tian, Siva; Juranek, Jenifer; Fletcher, Jack M.; Francis, David J.

2015-01-01

Objective Weak structure-function relations for brain and behavior may stem from problems in estimating these relations in small clinical samples with frequently occurring outliers. In the current project, we focused on the utility of using alternative statistics to estimate these relations. Method Fifty-four children with spina bifida meningomyelocele performed attention tasks and received MRI of the brain. Using a bootstrap sampling process, the Pearson product moment correlation was compared with four robust correlations: the percentage bend correlation, the Winsorized correlation, the skipped correlation using the Donoho-Gasko median, and the skipped correlation using the minimum volume ellipsoid estimator Results All methods yielded similar estimates of the relations between measures of brain volume and attention performance. The similarity of estimates across correlation methods suggested that the weak structure-function relations previously found in many studies are not readily attributable to the presence of outlying observations and other factors that violate the assumptions behind the Pearson correlation. Conclusions Given the difficulty of assembling large samples for brain-behavior studies, estimating correlations using multiple, robust methods may enhance the statistical conclusion validity of studies yielding small, but often clinically significant, correlations. PMID:25495830

Lumbar multifidus and erector spinae electromyograms during back bridge exercise in time and frequency domains.

PubMed

Mello, Roger Gomes Tavares; Carriço, Igor Rodrigues; da Matta, Thiago Torres; Nadal, Jurandir; Oliveira, Liliam Fernandes

2016-01-01

Muscle activity is studied during trunk stabilization exercises using electromyograms (EMG) in time domain. However, the frequency domain analysis provides information that would be important to understand fatigue process. To assess EMG of lumbar multifidus (LM) and erector spinae (ES) muscles, in time and frequency domains, during back bridge exercise. Nineteen healthy young men performed the exercise for one minute and EMG was monitored by surface electromyography. Normalized root mean square (RMS) value and spectral median frequency (MF) were compared between beginning and final epochs of test. The dynamics of the MF during whole test was also obtained by short-time Fourier transform. RMS values were about 30% of maximum voluntary contraction, and LM muscle showed greater MF than ES, which did not decrease at the final of exercise. However, the slope of MF was significant mainly for LM. Muscle activation of 30% is sufficient to keep lumbar stability and is suitable to improve muscular endurance. The significance of MF slope without decreasing at the final of exercise indicates challenging muscular endurance without imply on high fatigability. Due to lower muscular demand, this exercise might be recommended for trunk stabilizing for low back pain patients.

Monte Carlo simulations in X-ray imaging

NASA Astrophysics Data System (ADS)

Giersch, Jürgen; Durst, Jürgen

2008-06-01

Monte Carlo simulations have become crucial tools in many fields of X-ray imaging. They help to understand the influence of physical effects such as absorption, scattering and fluorescence of photons in different detector materials on image quality parameters. They allow studying new imaging concepts like photon counting, energy weighting or material reconstruction. Additionally, they can be applied to the fields of nuclear medicine to define virtual setups studying new geometries or image reconstruction algorithms. Furthermore, an implementation of the propagation physics of electrons and photons allows studying the behavior of (novel) X-ray generation concepts. This versatility of Monte Carlo simulations is illustrated with some examples done by the Monte Carlo simulation ROSI. An overview of the structure of ROSI is given as an example of a modern, well-proven, object-oriented, parallel computing Monte Carlo simulation for X-ray imaging.

Prospective sonographic detection of spina bifida at 11-14 weeks and systematic literature review.

PubMed

Orlandi, Emanuela; Rossi, Cinzia; Perino, Antonio; Cucinella, Gaspare; Orlandi, Francesco

2016-01-01

To conduct a literature review to assess the effectiveness of first trimester ultrasonographic markers of spina bifida (SB) integrating data with our prospective experience. The analysis of the SB cases that we prospectively detected in the first trimester, between January 2012 and February 2014, and a systematic review of all the papers evaluating the effectiveness of SB ultrasonographic markers at 11-14 weeks, namely brain stem diameter (BS), fourth ventricle/intracranial translucency (IT), cisterna magna (CM), brain stem/occipital bone distance (BSOB), the ratio between BS and BSOB. Some studies assess only the effectiveness of IT, others include more parameters, and few include them all. We prospectively detected four SB cases, three open (OSB) and one closed (CSB), in a low risk population undergoing first trimester screening. In the three OSB, CM (in 2/3 cases) and BSOB (3/3) distance were below the 5th percentile, BS and BS/BSOB ratio (3/3) were above the 95th percentile. In the CSB, all the measurements were within normal limits. The literature and our data agree that most fetuses with OSB demonstrate in the first trimester positive sonographic markers in the posterior fossa, but additional prospective studies are needed to establish the best protocol for OSB screening.

Multilevel sequential Monte Carlo samplers

DOE PAGES

Beskos, Alexandros; Jasra, Ajay; Law, Kody; ...

2016-08-24

Here, we study the approximation of expectations w.r.t. probability distributions associated to the solution of partial differential equations (PDEs); this scenario appears routinely in Bayesian inverse problems. In practice, one often has to solve the associated PDE numerically, using, for instance finite element methods and leading to a discretisation bias, with the step-size level h L. In addition, the expectation cannot be computed analytically and one often resorts to Monte Carlo methods. In the context of this problem, it is known that the introduction of the multilevel Monte Carlo (MLMC) method can reduce the amount of computational effort to estimate expectations, for a given level of error. This is achieved via a telescoping identity associated to a Monte Carlo approximation of a sequence of probability distributions with discretisation levelsmore » $${\\infty}$$ >h 0>h 1 ...>h L. In many practical problems of interest, one cannot achieve an i.i.d. sampling of the associated sequence of probability distributions. A sequential Monte Carlo (SMC) version of the MLMC method is introduced to deal with this problem. In conclusion, it is shown that under appropriate assumptions, the attractive property of a reduction of the amount of computational effort to estimate expectations, for a given level of error, can be maintained within the SMC context.« less

Mental health and parenting characteristics of caregivers of children with spina bifida.

PubMed

Malm-Buatsi, Elizabeth; Aston, Christopher E; Ryan, Jamie; Tao, Yeun; Palmer, Blake W; Kropp, Bradley P; Klein, Jake; Wisniewski, Amy B; Frimberger, Dominic

2015-04-01

Within the chronic medical illness literature, associations exist between caring for an affected child and parent mental health. The few studies examining both mothers and fathers provide mixed results. The purpose of this study is to examine associations between caregiver anxiety, depression, and parenting variables in caregivers of youth with SB as these relate to marital status, age, education, household income, work status, and child's severity of SB. The aim of this study is to examine associations between anxiety, depression, and parenting variables in caregivers of youth with spina bifida and how they relate to demographic and disease variables. Exploratory analyses examined the relationship between participation in support activities and depressive and anxious symptomatology and parenting characteristics. Eighty-four primary caregivers (49 mothers) of 51 youth with spina bifida completed measures of depressive and anxious symptomology, parenting stress, parent overprotection, and perceived child vulnerability. There were differences between mothers and fathers on several parenting characteristics; however, these were related more to marital status and employment than to gender of the caretaker per se. In the 33 married/remarried couples for whom both spouses participated, stress for the mothers was correlated with stress for the fathers. This correlation was strongest in the 12 married couples in which the mother works. Higher perceived vulnerability scores were reported in parents of SB patients in the younger age group, especially preschoolers (0-4 years). Parents of children with shunts reported more anxiety, depression and perceived child vulnerability. Both male and female caregivers of younger children reported significantly higher protectiveness scores. Involvement in recreational activities with other families affected by SB was associated with more positive parenting characteristics for mothers. Stress and protectiveness were found to be positively

Summarizing Monte Carlo Results in Methodological Research.

ERIC Educational Resources Information Center

Harwell, Michael R.

Monte Carlo studies of statistical tests are prominently featured in the methodological research literature. Unfortunately, the information from these studies does not appear to have significantly influenced methodological practice in educational and psychological research. One reason is that Monte Carlo studies lack an overarching theory to guide…

Advanced Computational Methods for Monte Carlo Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Forrest B.

This course is intended for graduate students who already have a basic understanding of Monte Carlo methods. It focuses on advanced topics that may be needed for thesis research, for developing new state-of-the-art methods, or for working with modern production Monte Carlo codes.

Quantum speedup of Monte Carlo methods.

PubMed

Montanaro, Ashley

2015-09-08

Monte Carlo methods use random sampling to estimate numerical quantities which are hard to compute deterministically. One important example is the use in statistical physics of rapidly mixing Markov chains to approximately compute partition functions. In this work, we describe a quantum algorithm which can accelerate Monte Carlo methods in a very general setting. The algorithm estimates the expected output value of an arbitrary randomized or quantum subroutine with bounded variance, achieving a near-quadratic speedup over the best possible classical algorithm. Combining the algorithm with the use of quantum walks gives a quantum speedup of the fastest known classical algorithms with rigorous performance bounds for computing partition functions, which use multiple-stage Markov chain Monte Carlo techniques. The quantum algorithm can also be used to estimate the total variation distance between probability distributions efficiently.

Proton Upset Monte Carlo Simulation

NASA Technical Reports Server (NTRS)

O'Neill, Patrick M.; Kouba, Coy K.; Foster, Charles C.

2009-01-01

The Proton Upset Monte Carlo Simulation (PROPSET) program calculates the frequency of on-orbit upsets in computer chips (for given orbits such as Low Earth Orbit, Lunar Orbit, and the like) from proton bombardment based on the results of heavy ion testing alone. The software simulates the bombardment of modern microelectronic components (computer chips) with high-energy (.200 MeV) protons. The nuclear interaction of the proton with the silicon of the chip is modeled and nuclear fragments from this interaction are tracked using Monte Carlo techniques to produce statistically accurate predictions.

Monte Carlo modeling of spatial coherence: free-space diffraction

PubMed Central

Fischer, David G.; Prahl, Scott A.; Duncan, Donald D.

2008-01-01

We present a Monte Carlo method for propagating partially coherent fields through complex deterministic optical systems. A Gaussian copula is used to synthesize a random source with an arbitrary spatial coherence function. Physical optics and Monte Carlo predictions of the first- and second-order statistics of the field are shown for coherent and partially coherent sources for free-space propagation, imaging using a binary Fresnel zone plate, and propagation through a limiting aperture. Excellent agreement between the physical optics and Monte Carlo predictions is demonstrated in all cases. Convergence criteria are presented for judging the quality of the Monte Carlo predictions. PMID:18830335

Quantum speedup of Monte Carlo methods

PubMed Central

Montanaro, Ashley

2015-01-01

Monte Carlo methods use random sampling to estimate numerical quantities which are hard to compute deterministically. One important example is the use in statistical physics of rapidly mixing Markov chains to approximately compute partition functions. In this work, we describe a quantum algorithm which can accelerate Monte Carlo methods in a very general setting. The algorithm estimates the expected output value of an arbitrary randomized or quantum subroutine with bounded variance, achieving a near-quadratic speedup over the best possible classical algorithm. Combining the algorithm with the use of quantum walks gives a quantum speedup of the fastest known classical algorithms with rigorous performance bounds for computing partition functions, which use multiple-stage Markov chain Monte Carlo techniques. The quantum algorithm can also be used to estimate the total variation distance between probability distributions efficiently. PMID:26528079

Mother–Adolescent Agreement Regarding Decision-Making Autonomy: A Longitudinal Comparison of Families of Adolescents with and without Spina Bifida

PubMed Central

Devine, Katie A.; Wasserman, Rachel M.; Gershenson, Lily S.; Essner, Bonnie S.

2011-01-01

Objective Longitudinal comparison of mother and adolescent agreement regarding decision-making autonomy for adolescents with and without spina bifida (SB). Methods Forty-two mother–adolescent dyads of adolescents with SB and 55 comparison dyads reported on who was responsible for decision-making across five waves of data collection, beginning at age 8 or 9 years through age 16 or 17 years. Results The proportion of tasks that dyads agreed were decided by adolescents increased over time for both samples beginning at age 12 or 13 years, but appeared to be delayed by roughly two years for youth with SB and was lower for youth with SB from lower socioeconomic (SES) backgrounds. Mothers and adolescents with low SES demonstrated higher proportions of tasks that dyads agreed were decided by mothers. Conclusions SB and low SES are risk factors for lower levels of agreed-upon decision-making autonomy. Future studies should examine how parent–adolescent agreement regarding autonomy relates to psychosocial outcomes. PMID:20943730

The X-43A Six Degree of Freedom Monte Carlo Analysis

NASA Technical Reports Server (NTRS)

Baumann, Ethan; Bahm, Catherine; Strovers, Brian; Beck, Roger

2008-01-01

This report provides an overview of the Hyper-X research vehicle Monte Carlo analysis conducted with the six-degree-of-freedom simulation. The methodology and model uncertainties used for the Monte Carlo analysis are presented as permitted. In addition, the process used to select hardware validation test cases from the Monte Carlo data is described. The preflight Monte Carlo analysis indicated that the X-43A control system was robust to the preflight uncertainties and provided the Hyper-X project an important indication that the vehicle would likely be successful in accomplishing the mission objectives. The X-43A inflight performance is compared to the preflight Monte Carlo predictions and shown to exceed the Monte Carlo bounds in several instances. Possible modeling shortfalls are presented that may account for these discrepancies. The flight control laws and guidance algorithms were robust enough as a result of the preflight Monte Carlo analysis that the unexpected in-flight performance did not have undue consequences. Modeling and Monte Carlo analysis lessons learned are presented.

The X-43A Six Degree of Freedom Monte Carlo Analysis

NASA Technical Reports Server (NTRS)

Baumann, Ethan; Bahm, Catherine; Strovers, Brian; Beck, Roger; Richard, Michael

2007-01-01

This report provides an overview of the Hyper-X research vehicle Monte Carlo analysis conducted with the six-degree-of-freedom simulation. The methodology and model uncertainties used for the Monte Carlo analysis are presented as permitted. In addition, the process used to select hardware validation test cases from the Monte Carlo data is described. The preflight Monte Carlo analysis indicated that the X-43A control system was robust to the preflight uncertainties and provided the Hyper-X project an important indication that the vehicle would likely be successful in accomplishing the mission objectives. The X-43A in-flight performance is compared to the preflight Monte Carlo predictions and shown to exceed the Monte Carlo bounds in several instances. Possible modeling shortfalls are presented that may account for these discrepancies. The flight control laws and guidance algorithms were robust enough as a result of the preflight Monte Carlo analysis that the unexpected in-flight performance did not have undue consequences. Modeling and Monte Carlo analysis lessons learned are presented.

MontePython 3: Parameter inference code for cosmology

NASA Astrophysics Data System (ADS)

Brinckmann, Thejs; Lesgourgues, Julien; Audren, Benjamin; Benabed, Karim; Prunet, Simon

2018-05-01

MontePython 3 provides numerous ways to explore parameter space using Monte Carlo Markov Chain (MCMC) sampling, including Metropolis-Hastings, Nested Sampling, Cosmo Hammer, and a Fisher sampling method. This improved version of the Monte Python (ascl:1307.002) parameter inference code for cosmology offers new ingredients that improve the performance of Metropolis-Hastings sampling, speeding up convergence and offering significant time improvement in difficult runs. Additional likelihoods and plotting options are available, as are post-processing algorithms such as Importance Sampling and Adding Derived Parameter.

Auditory interhemispheric transfer in relation to patterns of partial agenesis and hypoplasia of the corpus callosum in spina bifida meningomyelocele

PubMed Central

Hannay, H. Julia; Walker, Amy; Dennis, Maureen; Kramer, Larry; Blaser, Susan; Fletcher, Jack M.

2009-01-01

Spina bifida meningomyelocele with hydrocephalus (SBM) is commonly associated with anomalies of the corpus callosum (CC). We describe MRI patterns of regional CC agenesis and relate CC anomalies to functional laterality based on a dichotic listening test in 90 children with SBM and 27 typically developing controls. Many children with SBM (n = 40) showed regional CC anomalies in the form of agenesis of the rostrum and0or splenium, and a smaller number (n = 20) showed hypoplasia (thinning) of all CC regions (rostrum, genu, body, and splenium). The expected right ear advantage (REA) was exhibited by normal controls and children with SBM having a normal or hypoplastic splenium. It was not shown by children with SBM who were left handed, missing a splenium, or had a higher level spinal cord lesion. Perhaps the right hemisphere of these children is more involved in processing some aspects of linguistic stimuli. PMID:18764972

Goal management training of executive functions in patients with spina bifida: a randomized controlled trial.

PubMed

Stubberud, Jan; Langenbahn, Donna; Levine, Brian; Stanghelle, Johan; Schanke, Anne-Kristine

2013-07-01

Executive dysfunction causes significant real-life disability for patients with spina bifida (SB). However, no previous research has been directed toward the amelioration of executive functioning deficits amongst persons with SB. Goal Management Training (GMT) is a compensatory cognitive rehabilitation approach, addressing underlying deficits in sustained attention to improve executive function. GMT has received empirical support in studies of other patient groups. The purpose of the present study was to determine the efficacy of GMT in treating subjects with SB, using inpatient intervention periods. We hypothesized post-intervention changes in scores on neuropsychological measures to reflect improved attentional control, including sustained attention and inhibitory control. Thirty-eight adult subjects with SB were included in this randomized controlled trial. Inclusion was based upon the presence of executive functioning complaints. Experimental subjects (n = 24) received 21 hr of GMT, with efficacy of GMT being compared to results of subjects in a wait-list condition (n = 14). All subjects were assessed at baseline, post-intervention, and at 6-month follow-up. Findings indicated superior effects of GMT on domain-specific neuropsychological measures and on a functional "real-life" measure, all lasting at least 6 months post-treatment. These results show that deficits in executive functioning can be ameliorated in patients with congenital brain dysfunction.

Electromyographic analyses of the erector spinae muscles during golf swings using four different clubs.

PubMed

Sorbie, Graeme G; Grace, Fergal M; Gu, Yaodong; Baker, Julien S; Ugbolue, Ukadike C

2018-04-01

The purpose of this study was to compare the electromyography (EMG) patterns of the thoracic and lumbar regions of the erector spinae (ES) muscle during the golf swing whilst using four different golf clubs. Fifteen right-handed male golfers performed a total of twenty swings in random order using the driver, 4-iron, 7-iron and pitching-wedge. Surface EMG was recorded from the lead and trail sides of the thoracic and lumbar regions of the ES muscle (T8, L1 and L5 lateral to the spinous-process). Three-dimensional high-speed video analysis was used to identify the backswing, forward swing, acceleration, early and late follow-through phases of the golf swing. No significant differences in muscle-activation levels from the lead and trail sides of the thoracic and lumbar regions of the ES muscle were displayed between the driver, 4-iron, 7-iron and pitching-wedge (P > 0.05). The highest mean thoracic and lumbar ES muscle-activation levels were displayed in the forward swing (67-99% MVC) and acceleration (83-106% MVC) phases of the swing for all clubs tested. The findings from this study show that there were no significant statistical differences between the driver, 4-iron, 7-iron and pitching-wedge when examining muscle activity from the thoracic and lumbar regions of the ES muscle.

Educational career and predictors of type of education in young adults with spina bifida.

PubMed

Barf, H A; Verhoef, M; Post, M W M; Jennekens-Schinkel, A; Gooskens, R H J M; Mullaart, R A; Prevo, A J H

2004-03-01

Children with spina bifida (SB) often require special education. To date, little information is available about the educational career of these children. This study focuses on educational career and predictors of attending special education of young adults with SB, using a cross-sectional study including 178 young Dutch adults with SB aged from 16-25. The main outcome was attending regular versus special education. For searching predictive power we selected age, gender, type of SB, level of lesion, hydrocephalus (HC), number of surgical interventions, ambulation, continence and cognitive functioning. Chi-square tests and binary logistic regression were used in the data analysis. Participants with HC attended special primary education more often (59%) than participants without HC (17%). For those participants with HC, the necessity of special primary education was associated with below average intelligence (75% versus 35%), wheelchair dependence (82% versus 39%) and surgical interventions (74% versus 44%). Only half of the participants with HC followed regular secondary education, whereas for participants with SB without HC, the outcome in secondary education was similar to that of the general population (92%). Intelligence was the main predictor of attending special secondary education (odds 5.1:1), but HC (odds 4.3:1) and wheelchair dependence (odds 2.6:1) were also a significant. Other variables were not significant predictors of special secondary education.

An unbiased Hessian representation for Monte Carlo PDFs.

PubMed

Carrazza, Stefano; Forte, Stefano; Kassabov, Zahari; Latorre, José Ignacio; Rojo, Juan

We develop a methodology for the construction of a Hessian representation of Monte Carlo sets of parton distributions, based on the use of a subset of the Monte Carlo PDF replicas as an unbiased linear basis, and of a genetic algorithm for the determination of the optimal basis. We validate the methodology by first showing that it faithfully reproduces a native Monte Carlo PDF set (NNPDF3.0), and then, that if applied to Hessian PDF set (MMHT14) which was transformed into a Monte Carlo set, it gives back the starting PDFs with minimal information loss. We then show that, when applied to a large Monte Carlo PDF set obtained as combination of several underlying sets, the methodology leads to a Hessian representation in terms of a rather smaller set of parameters (MC-H PDFs), thereby providing an alternative implementation of the recently suggested Meta-PDF idea and a Hessian version of the recently suggested PDF compression algorithm (CMC-PDFs). The mc2hessian conversion code is made publicly available together with (through LHAPDF6) a Hessian representations of the NNPDF3.0 set, and the MC-H PDF set.

Diffusion Monte Carlo approach versus adiabatic computation for local Hamiltonians

NASA Astrophysics Data System (ADS)

Bringewatt, Jacob; Dorland, William; Jordan, Stephen P.; Mink, Alan

2018-02-01

Most research regarding quantum adiabatic optimization has focused on stoquastic Hamiltonians, whose ground states can be expressed with only real non-negative amplitudes and thus for whom destructive interference is not manifest. This raises the question of whether classical Monte Carlo algorithms can efficiently simulate quantum adiabatic optimization with stoquastic Hamiltonians. Recent results have given counterexamples in which path-integral and diffusion Monte Carlo fail to do so. However, most adiabatic optimization algorithms, such as for solving MAX-k -SAT problems, use k -local Hamiltonians, whereas our previous counterexample for diffusion Monte Carlo involved n -body interactions. Here we present a 6-local counterexample which demonstrates that even for these local Hamiltonians there are cases where diffusion Monte Carlo cannot efficiently simulate quantum adiabatic optimization. Furthermore, we perform empirical testing of diffusion Monte Carlo on a standard well-studied class of permutation-symmetric tunneling problems and similarly find large advantages for quantum optimization over diffusion Monte Carlo.

Monte Carlo simulation of aorta autofluorescence

NASA Astrophysics Data System (ADS)

Kuznetsova, A. A.; Pushkareva, A. E.

2016-08-01

Results of numerical simulation of autofluorescence of the aorta by the method of Monte Carlo are reported. Two states of the aorta, normal and with atherosclerotic lesions, are studied. A model of the studied tissue is developed on the basis of information about optical, morphological, and physico-chemical properties. It is shown that the data obtained by numerical Monte Carlo simulation are in good agreement with experimental results indicating adequacy of the developed model of the aorta autofluorescence.

Condition Self-Management in Pediatric Spina Bifida: A Longitudinal Investigation of Medical Adherence, Responsibility-Sharing, and Independence Skills.

PubMed

Psihogios, Alexandra M; Kolbuck, Victoria; Holmbeck, Grayson N

2015-09-01

This study aimed to evaluate rates of medical adherence, responsibility, and independence skills across late childhood and adolescence in youth with spina bifida (SB) and to explore associations among these disease self-management variables. 111 youth with SB, their parents, and a health professional participated at two time points. Informants completed questionnaires regarding medical adherence, responsibility-sharing, and child independence skills. Youth gained more responsibility and independence skills across time, although adherence rates did not follow a similar trajectory. Increased child medical responsibility was related to poorer adherence, and father-reported independence skills were associated with increased child responsibility. This study highlights medical domains that are the most difficult for families to manage (e.g., skin checks). Although youth appear to gain more autonomy across time, ongoing parental involvement in medical care may be necessary to achieve optimal adherence across adolescence. © The Author 2015. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Total prevention of folic acid-preventable spina bifida and anencephaly would reduce child mortality in India: Implications in achieving Target 3.2 of the Sustainable Development Goals.

PubMed

Kancherla, Vijaya; Oakley, Godfrey P

2018-03-15

The potential to reduce child mortality by preventing folic acid-preventable spina bifida and anencephaly (FAP SBA) is inadequately appreciated. To quantify possible reduction in FAP SBA-associated child mortality in low- and middle-income countries, we conducted an analysis to demonstrate in India, a country with more than 25 million births and 1.2 million under-five deaths each year, the decrease in neonatal, infant, and under-five mortality that would occur through total prevention of FAP SBA. We estimated the percent reductions in neonatal, infant, and under-five mortality that would have occurred in India in 2015 had all of FAP SBA been prevented. We also estimated the contributions of these reductions toward India's Sustainable Development Goals on child mortality indicators. We considered the overall prevalence of spina bifida and anencephaly in India as 5 per 1,000 live births, of which 90% were preventable with effective folic acid intervention. In the year 2015, folic acid interventions would have prevented about 116,070 cases of FAP SBA and 101,565 under-five deaths associated with FAP SBA. Prevention of FAP SBA would have reduced annually, neonatal, infant, and under-five mortality by 10.2%, 8.9%, and 8.3%, respectively. These reductions would have contributed 18.5% and 17.2% to the reductions in neonatal and under-five mortality, respectively, needed by India to achieve its 2030 Sustainable Developmental Goal Target 3.2 addressing preventable child mortality. Total prevention of FAP SBA clearly has a significant potential for immediate reductions in neonatal, infant, and under-five mortality in India, and similarly other countries. © 2017 Wiley Periodicals, Inc.

Discrete Diffusion Monte Carlo for Electron Thermal Transport

NASA Astrophysics Data System (ADS)

Chenhall, Jeffrey; Cao, Duc; Wollaeger, Ryan; Moses, Gregory

2014-10-01

The iSNB (implicit Schurtz Nicolai Busquet electron thermal transport method of Cao et al. is adapted to a Discrete Diffusion Monte Carlo (DDMC) solution method for eventual inclusion in a hybrid IMC-DDMC (Implicit Monte Carlo) method. The hybrid method will combine the efficiency of a diffusion method in short mean free path regions with the accuracy of a transport method in long mean free path regions. The Monte Carlo nature of the approach allows the algorithm to be massively parallelized. Work to date on the iSNB-DDMC method will be presented. This work was supported by Sandia National Laboratory - Albuquerque.

Off-diagonal expansion quantum Monte Carlo

NASA Astrophysics Data System (ADS)

Albash, Tameem; Wagenbreth, Gene; Hen, Itay

2017-12-01

We propose a Monte Carlo algorithm designed to simulate quantum as well as classical systems at equilibrium, bridging the algorithmic gap between quantum and classical thermal simulation algorithms. The method is based on a decomposition of the quantum partition function that can be viewed as a series expansion about its classical part. We argue that the algorithm not only provides a theoretical advancement in the field of quantum Monte Carlo simulations, but is optimally suited to tackle quantum many-body systems that exhibit a range of behaviors from "fully quantum" to "fully classical," in contrast to many existing methods. We demonstrate the advantages, sometimes by orders of magnitude, of the technique by comparing it against existing state-of-the-art schemes such as path integral quantum Monte Carlo and stochastic series expansion. We also illustrate how our method allows for the unification of quantum and classical thermal parallel tempering techniques into a single algorithm and discuss its practical significance.

Off-diagonal expansion quantum Monte Carlo.

PubMed

Albash, Tameem; Wagenbreth, Gene; Hen, Itay

2017-12-01

We propose a Monte Carlo algorithm designed to simulate quantum as well as classical systems at equilibrium, bridging the algorithmic gap between quantum and classical thermal simulation algorithms. The method is based on a decomposition of the quantum partition function that can be viewed as a series expansion about its classical part. We argue that the algorithm not only provides a theoretical advancement in the field of quantum Monte Carlo simulations, but is optimally suited to tackle quantum many-body systems that exhibit a range of behaviors from "fully quantum" to "fully classical," in contrast to many existing methods. We demonstrate the advantages, sometimes by orders of magnitude, of the technique by comparing it against existing state-of-the-art schemes such as path integral quantum Monte Carlo and stochastic series expansion. We also illustrate how our method allows for the unification of quantum and classical thermal parallel tempering techniques into a single algorithm and discuss its practical significance.

RECORDS: improved Reporting of montE CarlO RaDiation transport Studies: Report of the AAPM Research Committee Task Group 268.

PubMed

Sechopoulos, Ioannis; Rogers, D W O; Bazalova-Carter, Magdalena; Bolch, Wesley E; Heath, Emily C; McNitt-Gray, Michael F; Sempau, Josep; Williamson, Jeffrey F

2018-01-01

Studies involving Monte Carlo simulations are common in both diagnostic and therapy medical physics research, as well as other fields of basic and applied science. As with all experimental studies, the conditions and parameters used for Monte Carlo simulations impact their scope, validity, limitations, and generalizability. Unfortunately, many published peer-reviewed articles involving Monte Carlo simulations do not provide the level of detail needed for the reader to be able to properly assess the quality of the simulations. The American Association of Physicists in Medicine Task Group #268 developed guidelines to improve reporting of Monte Carlo studies in medical physics research. By following these guidelines, manuscripts submitted for peer-review will include a level of relevant detail that will increase the transparency, the ability to reproduce results, and the overall scientific value of these studies. The guidelines include a checklist of the items that should be included in the Methods, Results, and Discussion sections of manuscripts submitted for peer-review. These guidelines do not attempt to replace the journal reviewer, but rather to be a tool during the writing and review process. Given the varied nature of Monte Carlo studies, it is up to the authors and the reviewers to use this checklist appropriately, being conscious of how the different items apply to each particular scenario. It is envisioned that this list will be useful both for authors and for reviewers, to help ensure the adequate description of Monte Carlo studies in the medical physics literature. © 2017 American Association of Physicists in Medicine.

Motor unit potentials of the erector spinae muscle by concentric needle electromyography.

PubMed

Posa, Andreas; Niśkiewicz, Izabela; Emmer, Alexander; Kluge, Yorck; Kornhuber, Malte E

2017-03-01

The needle electromyography (EMG) serves to supply additional information in patients with suspected neuromuscular disorders. We aimed to provide motor unit potential (MUP) data by concentric needle EMG in the erector spinae (ES) in comparison with biceps brachii (BB) and lateral vastus (LV). Electromyography MUP data ( n ) were obtained in ES (517), BB (539), and LV (627) in 32 healthy volunteers (16f). Motor unit potential data: amplitude (μV) 393 ± 174 (ES), 375 ± 162 (BB), and 577 ± 304 (LV); duration (ms) 10.4 ± 2.4 (ES), 10.1 ± 2.1 (BB), and 11.1 ± 2.3 (LV), area (μV × ms) 585 ± 327 (ES), 538 ± 267 (BB), and 881 ± 492 (LV); phase number 3.23 ± 0.94 (ES), 2.98 ± 0.76 (BB), and 3.19 ± 0.81 (LV); size index 0.60 ± 0.56 (ES), 0.51 ± 0.53 (BB), and 0.96 ± 0.55 (LV). LV displayed higher values ( p at least <.001) for MUP amplitude, duration, area, and size index as compared to both, BB and ES. Concentric needle EMG investigations in healthy adult human subjects revealed similar MUP parameters in the ES and BB muscles, while in the LV muscle MUP amplitude, duration, area, and size index were significantly larger. Different neuromuscular disorders display a predominant involvement of proximally located muscles such as truncal muscles. The present results given here may facilitate the diagnosis of neuromuscular disorders.

Monte Carlo simulation: Its status and future

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murtha, J.A.

1997-04-01

Monte Carlo simulation is a statistics-based analysis tool that yields probability-vs.-value relationships for key parameters, including oil and gas reserves, capital exposure, and various economic yardsticks, such as net present value (NPV) and return on investment (ROI). Monte Carlo simulation is a part of risk analysis and is sometimes performed in conjunction with or as an alternative to decision [tree] analysis. The objectives are (1) to define Monte Carlo simulation in a more general context of risk and decision analysis; (2) to provide some specific applications, which can be interrelated; (3) to respond to some of the criticisms; (4) tomore » offer some cautions about abuses of the method and recommend how to avoid the pitfalls; and (5) to predict what the future has in store.« less

Hybrid Monte Carlo/deterministic methods for radiation shielding problems

NASA Astrophysics Data System (ADS)

Becker, Troy L.

For the past few decades, the most common type of deep-penetration (shielding) problem simulated using Monte Carlo methods has been the source-detector problem, in which a response is calculated at a single location in space. Traditionally, the nonanalog Monte Carlo methods used to solve these problems have required significant user input to generate and sufficiently optimize the biasing parameters necessary to obtain a statistically reliable solution. It has been demonstrated that this laborious task can be replaced by automated processes that rely on a deterministic adjoint solution to set the biasing parameters---the so-called hybrid methods. The increase in computational power over recent years has also led to interest in obtaining the solution in a region of space much larger than a point detector. In this thesis, we propose two methods for solving problems ranging from source-detector problems to more global calculations---weight windows and the Transform approach. These techniques employ sonic of the same biasing elements that have been used previously; however, the fundamental difference is that here the biasing techniques are used as elements of a comprehensive tool set to distribute Monte Carlo particles in a user-specified way. The weight window achieves the user-specified Monte Carlo particle distribution by imposing a particular weight window on the system, without altering the particle physics. The Transform approach introduces a transform into the neutron transport equation, which results in a complete modification of the particle physics to produce the user-specified Monte Carlo distribution. These methods are tested in a three-dimensional multigroup Monte Carlo code. For a basic shielding problem and a more realistic one, these methods adequately solved source-detector problems and more global calculations. Furthermore, they confirmed that theoretical Monte Carlo particle distributions correspond to the simulated ones, implying that these methods

Formulation and evaluation of antihyperglycemic leaf extracts of Zizyphus spina-christi (L.) Willd.

PubMed

Nesseem, D I; Michel, C G; Sleem, A A; El-Alfy, T S

2009-02-01

This study deals with the formulation of antihyperglycemic leaf extracts of Zizyphus spina-christi (L.) Willd. A bioactivity guided fractionation of different leaf extracts [defatted ethanol 70% (a), butanol (b), ethanol 70% (c), ethyl acetate (d) and petroleum ether (e) extracts] revealed that extract (c) possessed the highest antihyperglycemic activity followed by (b) and (a). HPLC was adopted for standardization of the extract (c) based on evaluation of the major saponin christinin-A which was used as marker. The detection limit was 9.45 mg/ml for Christinin-A. Extracts (a), (b) and (c) were separately formulated in soft (S) and hard (H) gelatin capsules. Two different formulations (F1 and F2) were tried using different excipients suitable for oral drug delivery. Formula 1, used for soft gelatin capsules [(F1) Sa, Sb, Sc] Formula 2, used for hard gelatin capsules [(F2) - Ha, Hb, Hc]. The recovery rates of the samples of saponin were in the range 99.43-101.86% at 200, 800 microg/ml and 1200 microg/ml. Saponin release rates from different formulae were carried out using dissolution tester USP XXIV. The highest release was obtained from formulation Sc. The release of the extracts followed diffusion mechanism. The selected formula Sc exhibited highest anti-diabetic activity (P < 0.01) on acute and long-term administration and highest saponin release. This formula (Sc) contained poly-oxyethylene (20) cetyl ether (BC-20TX), PEG 400, PEG 6000, purified water, meglyol 810, ascorbic acid and 200 mg of extract (c).

What young people with spina bifida want to know about sex, and aren’t being told

PubMed Central

LIGHT, Alexis; SHERMAN, Laura; POLVINEN, Julie; RICH, Michael

2015-01-01

Objective To examine sexual knowledge, concerns, and needs of youth with spina bifida (SB) to inform the medical community on ways to better support their sexual health. Methods As part of the Video Intervention/Prevention Assessment (VIA) – Transitions, a prospective cohort study, 309 hours of video data were collected from 14 participants (13–28 years) with SB. Participants were loaned a video camcorder for 8–12 weeks to shoot visual narratives about any aspects of their lives. VIA visual narratives were analyzed with Grounded Theory using NVivo. Results Out of 14 participants, 11 (6 females) addressed issues surrounding romantic relationships and sexuality in their video clips. Analysis revealed shared concerns, questions, and challenges regarding sexuality gathered under 4 main themes: romantic relationships, sexuality, fertility and parenthood, and need for more talk on sexuality. Conclusions Youth with SB reported difficulties in finding answers to questions regarding their sexuality, romantic relationships, and fertility. This study revealed a need for help from the medical community to inform and empower youth with SB in the area of sexual health. Through sexual and reproductive health education with patients and parents starting at an early age, medical providers can further encourage healthy emotional and physical development in adolescents transitioning into adulthood. PMID:26331351

Neuroimaging parameters in early open spina bifida detection. Further benefit in first trimester screening?

PubMed

Iliescu, D; Comănescu, A; Antsaklis, P; Tudorache, Stefania; Ghiluşi, Mirela; Comănescu, Violeta; Paulescu, Daniela; Ceauşu, Iuliana; Antsaklis, A; Novac, Liliana; Cernea, N

2011-01-01

Morphological investigation of the central nervous system (CNS) in fetuses with positive markers for open spina bifida (OSB) detection, visualized by ultrasound during the first trimester of pregnancy. Data from fetuses that underwent routine first trimester ultrasound scan in our center during September 2007-March 2011 and presented abnormal aspects of the fourth ventricle, also referred as intracranial translucency (IT), provided the morphological support to evaluate CNS features. A neuro-histological study of posterior cerebral fossa illustrated anatomical features of the structures involved in the sonographic first trimester detection of neural tube defects. Abnormal IT aspects were found in OSB cases examined in the first trimester, but also in other severe cerebral abnormalities. Brain stem antero-posterior diameter (BS) and brain stem to occipital bone (BSOB) ratio may be more specific for OSB detection. Correlations between histological aspects of posterior brain fossa and ultrasound standard assessment have been made; highlighting the anatomical features involved by the new techniques developed for OSB early detection. Preliminary results show that modern sonographic protocols are capable to detect abnormalities in the morphometry of the posterior brain. First trimester fourth ventricle abnormalities should be followed by careful CNS evaluation because are likely to appear in OSB affected fetuses, but also in other CNS severe anomalies; in such cases, normal BS and BSOB ratio may serve as indirect argument for spine integrity, if specificity is confirmed in large series of fetuses.

Wet-based glaciation in Phlegra Montes, Mars.

NASA Astrophysics Data System (ADS)

Gallagher, Colman; Balme, Matt

2016-04-01

Eskers are sinuous landforms composed of sediments deposited from meltwaters in ice-contact glacial conduits. This presentation describes the first definitive identification of eskers on Mars still physically linked with their parent system (1), a Late Amazonian-age glacier (~150 Ma) in Phlegra Montes. Previously described Amazonian-age glaciers on Mars are generally considered to have been dry based, having moved by creep in the absence of subglacial water required for sliding, but our observations indicate significant sub-glacial meltwater routing. The confinement of the Phlegra Montes glacial system to a regionally extensive graben is evidence that the esker formed due to sub-glacial melting in response to an elevated, but spatially restricted, geothermal heat flux rather than climate-induced warming. Now, however, new observations reveal the presence of many assemblages of glacial abrasion forms and associated channels that could be evidence of more widespread wet-based glaciation in Phlegra Montes, including the collapse of several distinct ice domes. This landform assemblage has not been described in other glaciated, mid-latitude regions of the martian northern hemisphere. Moreover, Phlegra Montes are flanked by lowlands displaying evidence of extensive volcanism, including contact between plains lava and piedmont glacial ice. These observations provide a rationale for investigating non-climatic forcing of glacial melting and associated landscape development on Mars, and can build on insights from Earth into the importance of geothermally-induced destabilisation of glaciers as a key amplifier of climate change. (1) Gallagher, C. and Balme, M. (2015). Eskers in a complete, wet-based glacial system in the Phlegra Montes region, Mars, Earth and Planetary Science Letters, 431, 96-109.

A Primer in Monte Carlo Integration Using Mathcad

ERIC Educational Resources Information Center

Hoyer, Chad E.; Kegerreis, Jeb S.

2013-01-01

The essentials of Monte Carlo integration are presented for use in an upper-level physical chemistry setting. A Mathcad document that aids in the dissemination and utilization of this information is described and is available in the Supporting Information. A brief outline of Monte Carlo integration is given, along with ideas and pedagogy for…

Baseball Monte Carlo Style.

ERIC Educational Resources Information Center

Houser, Larry L.

1981-01-01

Monte Carlo methods are used to simulate activities in baseball such as a team's "hot streak" and a hitter's "batting slump." Student participation in such simulations is viewed as a useful method of giving pupils a better understanding of the probability concepts involved. (MP)

The Monte Carlo Method. Popular Lectures in Mathematics.

ERIC Educational Resources Information Center

Sobol', I. M.

The Monte Carlo Method is a method of approximately solving mathematical and physical problems by the simulation of random quantities. The principal goal of this booklet is to suggest to specialists in all areas that they will encounter problems which can be solved by the Monte Carlo Method. Part I of the booklet discusses the simulation of random…

Effects of reading goals on reading comprehension, reading rate, and allocation of working memory in children and adolescents with spina bifida meningomyelocele

PubMed Central

ENGLISH, LIANNE; BARNES, MARCIA A.; FLETCHER, JACK M.; DENNIS, MAUREEN; RAGHUBAR, KIMBERLY P.

2011-01-01

Spina bifida meningomyelocele (SBM) is a neurodevelopmental disorder associated with intact word decoding and deficient text and discourse comprehension. This study investigated the ability to adjust reading in accordance with specified reading goals in 79 children and adolescents with SBM (9–19 years of age) and 39 controls (8–17 years of age). Both groups demonstrated slower reading times and enhanced comprehension when reading to study or to come up with a title than when reading for specific information or for entertainment. For both groups, verbal working memory contributed to comprehension performance in those reading conditions hypothesized to require more cognitive effort. Despite their sensitivity to the goals of reading, the group with SBM answered fewer comprehension questions correctly across all reading goal conditions. The results are discussed in relation to the hypothesized cognitive underpinnings of comprehension deficits in SBM and to current models of text comprehension. PMID:20338082

New Approaches and Applications for Monte Carlo Perturbation Theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aufiero, Manuele; Bidaud, Adrien; Kotlyar, Dan

2017-02-01

This paper presents some of the recent and new advancements in the extension of Monte Carlo Perturbation Theory methodologies and application. In particular, the discussed problems involve Brunup calculation, perturbation calculation based on continuous energy functions, and Monte Carlo Perturbation Theory in loosely coupled systems.

Cell-veto Monte Carlo algorithm for long-range systems.

PubMed

Kapfer, Sebastian C; Krauth, Werner

2016-09-01

We present a rigorous efficient event-chain Monte Carlo algorithm for long-range interacting particle systems. Using a cell-veto scheme within the factorized Metropolis algorithm, we compute each single-particle move with a fixed number of operations. For slowly decaying potentials such as Coulomb interactions, screening line charges allow us to take into account periodic boundary conditions. We discuss the performance of the cell-veto Monte Carlo algorithm for general inverse-power-law potentials, and illustrate how it provides a new outlook on one of the prominent bottlenecks in large-scale atomistic Monte Carlo simulations.

Recommender engine for continuous-time quantum Monte Carlo methods

NASA Astrophysics Data System (ADS)

Huang, Li; Yang, Yi-feng; Wang, Lei

2017-03-01

Recommender systems play an essential role in the modern business world. They recommend favorable items such as books, movies, and search queries to users based on their past preferences. Applying similar ideas and techniques to Monte Carlo simulations of physical systems boosts their efficiency without sacrificing accuracy. Exploiting the quantum to classical mapping inherent in the continuous-time quantum Monte Carlo methods, we construct a classical molecular gas model to reproduce the quantum distributions. We then utilize powerful molecular simulation techniques to propose efficient quantum Monte Carlo updates. The recommender engine approach provides a general way to speed up the quantum impurity solvers.

Nuclide Depletion Capabilities in the Shift Monte Carlo Code

DOE PAGES

Davidson, Gregory G.; Pandya, Tara M.; Johnson, Seth R.; ...

2017-12-21

A new depletion capability has been developed in the Exnihilo radiation transport code suite. This capability enables massively parallel domain-decomposed coupling between the Shift continuous-energy Monte Carlo solver and the nuclide depletion solvers in ORIGEN to perform high-performance Monte Carlo depletion calculations. This paper describes this new depletion capability and discusses its various features, including a multi-level parallel decomposition, high-order transport-depletion coupling, and energy-integrated power renormalization. Several test problems are presented to validate the new capability against other Monte Carlo depletion codes, and the parallel performance of the new capability is analyzed.

Rapid Monte Carlo Simulation of Gravitational Wave Galaxies

NASA Astrophysics Data System (ADS)

Breivik, Katelyn; Larson, Shane L.

2015-01-01

With the detection of gravitational waves on the horizon, astrophysical catalogs produced by gravitational wave observatories can be used to characterize the populations of sources and validate different galactic population models. Efforts to simulate gravitational wave catalogs and source populations generally focus on population synthesis models that require extensive time and computational power to produce a single simulated galaxy. Monte Carlo simulations of gravitational wave source populations can also be used to generate observation catalogs from the gravitational wave source population. Monte Carlo simulations have the advantes of flexibility and speed, enabling rapid galactic realizations as a function of galactic binary parameters with less time and compuational resources required. We present a Monte Carlo method for rapid galactic simulations of gravitational wave binary populations.

Relations between volumetric measures of brain structure and attentional function in spina bifida: utilization of robust statistical approaches.

PubMed

Kulesz, Paulina A; Tian, Siva; Juranek, Jenifer; Fletcher, Jack M; Francis, David J

2015-03-01

Weak structure-function relations for brain and behavior may stem from problems in estimating these relations in small clinical samples with frequently occurring outliers. In the current project, we focused on the utility of using alternative statistics to estimate these relations. Fifty-four children with spina bifida meningomyelocele performed attention tasks and received MRI of the brain. Using a bootstrap sampling process, the Pearson product-moment correlation was compared with 4 robust correlations: the percentage bend correlation, the Winsorized correlation, the skipped correlation using the Donoho-Gasko median, and the skipped correlation using the minimum volume ellipsoid estimator. All methods yielded similar estimates of the relations between measures of brain volume and attention performance. The similarity of estimates across correlation methods suggested that the weak structure-function relations previously found in many studies are not readily attributable to the presence of outlying observations and other factors that violate the assumptions behind the Pearson correlation. Given the difficulty of assembling large samples for brain-behavior studies, estimating correlations using multiple, robust methods may enhance the statistical conclusion validity of studies yielding small, but often clinically significant, correlations. PsycINFO Database Record (c) 2015 APA, all rights reserved.

French Alps, Mont Blanc, French/Italian Border

NASA Image and Video Library

1992-04-02

In this southeast looking view, Mont Blanc, on the French/Italian border, (48.0N, 4.5E) the highest mountain peak in all of Europe, is just below and right of center (below the end of the prominent valley of the Aosta River, in the center of the photo. The rivers flow out of the Alps into Italy toward Turin. Chamonix, the famous resort town and center of Alpine mountain climbing, lies in the valley just below Mont Blanc.

Numerical integration of detector response functions via Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Kelly, K. J.; O'Donnell, J. M.; Gomez, J. A.; Taddeucci, T. N.; Devlin, M.; Haight, R. C.; White, M. C.; Mosby, S. M.; Neudecker, D.; Buckner, M. Q.; Wu, C. Y.; Lee, H. Y.

2017-09-01

Calculations of detector response functions are complicated because they include the intricacies of signal creation from the detector itself as well as a complex interplay between the detector, the particle-emitting target, and the entire experimental environment. As such, these functions are typically only accessible through time-consuming Monte Carlo simulations. Furthermore, the output of thousands of Monte Carlo simulations can be necessary in order to extract a physics result from a single experiment. Here we describe a method to obtain a full description of the detector response function using Monte Carlo simulations. We also show that a response function calculated in this way can be used to create Monte Carlo simulation output spectra a factor of ∼ 1000 × faster than running a new Monte Carlo simulation. A detailed discussion of the proper treatment of uncertainties when using this and other similar methods is provided as well. This method is demonstrated and tested using simulated data from the Chi-Nu experiment, which measures prompt fission neutron spectra at the Los Alamos Neutron Science Center.

Numerical integration of detector response functions via Monte Carlo simulations

DOE PAGES

Kelly, Keegan John; O'Donnell, John M.; Gomez, Jaime A.; ...

2017-06-13

Calculations of detector response functions are complicated because they include the intricacies of signal creation from the detector itself as well as a complex interplay between the detector, the particle-emitting target, and the entire experimental environment. As such, these functions are typically only accessible through time-consuming Monte Carlo simulations. Furthermore, the output of thousands of Monte Carlo simulations can be necessary in order to extract a physics result from a single experiment. Here we describe a method to obtain a full description of the detector response function using Monte Carlo simulations. We also show that a response function calculated inmore » this way can be used to create Monte Carlo simulation output spectra a factor of ~1000× faster than running a new Monte Carlo simulation. A detailed discussion of the proper treatment of uncertainties when using this and other similar methods is provided as well. Here, this method is demonstrated and tested using simulated data from the Chi-Nu experiment, which measures prompt fission neutron spectra at the Los Alamos Neutron Science Center.« less

Numerical integration of detector response functions via Monte Carlo simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Keegan John; O'Donnell, John M.; Gomez, Jaime A.

Calculations of detector response functions are complicated because they include the intricacies of signal creation from the detector itself as well as a complex interplay between the detector, the particle-emitting target, and the entire experimental environment. As such, these functions are typically only accessible through time-consuming Monte Carlo simulations. Furthermore, the output of thousands of Monte Carlo simulations can be necessary in order to extract a physics result from a single experiment. Here we describe a method to obtain a full description of the detector response function using Monte Carlo simulations. We also show that a response function calculated inmore » this way can be used to create Monte Carlo simulation output spectra a factor of ~1000× faster than running a new Monte Carlo simulation. A detailed discussion of the proper treatment of uncertainties when using this and other similar methods is provided as well. Here, this method is demonstrated and tested using simulated data from the Chi-Nu experiment, which measures prompt fission neutron spectra at the Los Alamos Neutron Science Center.« less

Monte Carlo capabilities of the SCALE code system

DOE PAGES

Rearden, Bradley T.; Petrie, Jr., Lester M.; Peplow, Douglas E.; ...

2014-09-12

SCALE is a broadly used suite of tools for nuclear systems modeling and simulation that provides comprehensive, verified and validated, user-friendly capabilities for criticality safety, reactor physics, radiation shielding, and sensitivity and uncertainty analysis. For more than 30 years, regulators, licensees, and research institutions around the world have used SCALE for nuclear safety analysis and design. SCALE provides a “plug-and-play” framework that includes three deterministic and three Monte Carlo radiation transport solvers that can be selected based on the desired solution, including hybrid deterministic/Monte Carlo simulations. SCALE includes the latest nuclear data libraries for continuous-energy and multigroup radiation transport asmore » well as activation, depletion, and decay calculations. SCALE’s graphical user interfaces assist with accurate system modeling, visualization, and convenient access to desired results. SCALE 6.2 will provide several new capabilities and significant improvements in many existing features, especially with expanded continuous-energy Monte Carlo capabilities for criticality safety, shielding, depletion, and sensitivity and uncertainty analysis. Finally, an overview of the Monte Carlo capabilities of SCALE is provided here, with emphasis on new features for SCALE 6.2.« less

Parents' psychological adjustment in families of children with Spina Bifida: a meta-analysis

PubMed Central

Vermaes, Ignace PR; Janssens, Jan MAM; Bosman, Anna MT; Gerris, Jan RM

2005-01-01

Background Spina Bifida (SB) is the second most common birth defect worldwide. Since the chances of survival in children with severe SB-forms have increased, medical care has shifted its emphasis from life-saving interventions to fostering the quality of life for these children and their families. Little is known, however, about the impact of SB on family adjustment. Reviewers have struggled to synthesize the few contradictory studies available. In this systematic review a new attempt was made to summarize the findings by using meta-analysis and by delimiting the scope of review to one concept of family adjustment: Parents' psychological adjustment. The questions addressed were: (a) do parents of children with SB have more psychological distress than controls? (b) do mothers and fathers differ? and (c) which factors correlate with variations in psychological adjustment? Methods PsycInfo, Medline, and reference lists were scanned. Thirty-three relevant studies were identified of which 15 were eligible for meta-analysis. Results SB had a negative medium-large effect on parents' psychological adjustment. The effect was more heterogeneous for mothers than for fathers. In the reviewed studies child factors (age, conduct problems, emotional problems, and mental retardation), parent factors (SES, hope, appraised stress, coping, and parenting competence), family factors (family income, partner relationship, and family climate), and environmental factors (social support) were found to be associated with variations in parents' psychological adjustment. Conclusion Meta-analysis proved to be helpful in organizing studies. Clinical implications indicate a need to be especially alert to psychological suffering in mothers of children with SB. Future research should increase sample sizes through multi-center collaborations. PMID:16120229

Geodesic Monte Carlo on Embedded Manifolds

PubMed Central

Byrne, Simon; Girolami, Mark

2013-01-01

Markov chain Monte Carlo methods explicitly defined on the manifold of probability distributions have recently been established. These methods are constructed from diffusions across the manifold and the solution of the equations describing geodesic flows in the Hamilton–Jacobi representation. This paper takes the differential geometric basis of Markov chain Monte Carlo further by considering methods to simulate from probability distributions that themselves are defined on a manifold, with common examples being classes of distributions describing directional statistics. Proposal mechanisms are developed based on the geodesic flows over the manifolds of support for the distributions, and illustrative examples are provided for the hypersphere and Stiefel manifold of orthonormal matrices. PMID:25309024

The Rational Hybrid Monte Carlo algorithm

NASA Astrophysics Data System (ADS)

Clark, Michael

2006-12-01

The past few years have seen considerable progress in algorithmic development for the generation of gauge fields including the effects of dynamical fermions. The Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is performed using a rational approximation in place the usual inverse quark matrix kernel is one of these developments. This algorithm has been found to be extremely beneficial in many areas of lattice QCD (chiral fermions, finite temperature, Wilson fermions etc.). We review the algorithm and some of these benefits, and we compare against other recent algorithm developements. We conclude with an update of the Berlin wall plot comparing costs of all popular fermion formulations.

RNA folding kinetics using Monte Carlo and Gillespie algorithms.

PubMed

Clote, Peter; Bayegan, Amir H

2018-04-01

RNA secondary structure folding kinetics is known to be important for the biological function of certain processes, such as the hok/sok system in E. coli. Although linear algebra provides an exact computational solution of secondary structure folding kinetics with respect to the Turner energy model for tiny ([Formula: see text]20 nt) RNA sequences, the folding kinetics for larger sequences can only be approximated by binning structures into macrostates in a coarse-grained model, or by repeatedly simulating secondary structure folding with either the Monte Carlo algorithm or the Gillespie algorithm. Here we investigate the relation between the Monte Carlo algorithm and the Gillespie algorithm. We prove that asymptotically, the expected time for a K-step trajectory of the Monte Carlo algorithm is equal to [Formula: see text] times that of the Gillespie algorithm, where [Formula: see text] denotes the Boltzmann expected network degree. If the network is regular (i.e. every node has the same degree), then the mean first passage time (MFPT) computed by the Monte Carlo algorithm is equal to MFPT computed by the Gillespie algorithm multiplied by [Formula: see text]; however, this is not true for non-regular networks. In particular, RNA secondary structure folding kinetics, as computed by the Monte Carlo algorithm, is not equal to the folding kinetics, as computed by the Gillespie algorithm, although the mean first passage times are roughly correlated. Simulation software for RNA secondary structure folding according to the Monte Carlo and Gillespie algorithms is publicly available, as is our software to compute the expected degree of the network of secondary structures of a given RNA sequence-see http://bioinformatics.bc.edu/clote/RNAexpNumNbors .

MONTE: the next generation of mission design and navigation software

NASA Astrophysics Data System (ADS)

Evans, Scott; Taber, William; Drain, Theodore; Smith, Jonathon; Wu, Hsi-Cheng; Guevara, Michelle; Sunseri, Richard; Evans, James

2018-03-01

The Mission analysis, Operations and Navigation Toolkit Environment (MONTE) (Sunseri et al. in NASA Tech Briefs 36(9), 2012) is an astrodynamic toolkit produced by the Mission Design and Navigation Software Group at the Jet Propulsion Laboratory. It provides a single integrated environment for all phases of deep space and Earth orbiting missions. Capabilities include: trajectory optimization and analysis, operational orbit determination, flight path control, and 2D/3D visualization. MONTE is presented to the user as an importable Python language module. This allows a simple but powerful user interface via CLUI or script. In addition, the Python interface allows MONTE to be used seamlessly with other canonical scientific programming tools such as SciPy, NumPy, and Matplotlib. MONTE is the prime operational orbit determination software for all JPL navigated missions.

PyMercury: Interactive Python for the Mercury Monte Carlo Particle Transport Code

DOE Office of Scientific and Technical Information (OSTI.GOV)

Iandola, F N; O'Brien, M J; Procassini, R J

2010-11-29

Monte Carlo particle transport applications are often written in low-level languages (C/C++) for optimal performance on clusters and supercomputers. However, this development approach often sacrifices straightforward usability and testing in the interest of fast application performance. To improve usability, some high-performance computing applications employ mixed-language programming with high-level and low-level languages. In this study, we consider the benefits of incorporating an interactive Python interface into a Monte Carlo application. With PyMercury, a new Python extension to the Mercury general-purpose Monte Carlo particle transport code, we improve application usability without diminishing performance. In two case studies, we illustrate how PyMercury improvesmore » usability and simplifies testing and validation in a Monte Carlo application. In short, PyMercury demonstrates the value of interactive Python for Monte Carlo particle transport applications. In the future, we expect interactive Python to play an increasingly significant role in Monte Carlo usage and testing.« less

Inadvertent positioning of suprapubic catheter in urethra: a serious complication during change of suprapubic cystostomy in a spina bifida patient - a case report.

PubMed

Vaidyanathan, Subramanian; Hughes, Peter L; Soni, Bakul M; Oo, Tun; Singh, Gurpreet

2009-12-22

Spinal cord injury patients are at risk for developing unusual complications such as autonomic dysreflexia while changing suprapubic cystostomy. We report a male patient with spina bifida in whom the Foley catheter was placed in the urethra during change of suprapubic cystostomy with serious consequences. A male patient, born in 1972 with spina bifida and paraplaegia, underwent suprapubic cystostomy in 2003 because of increasing problems with urethral catheter. The patient would come to spinal unit for change of suprapubic catheter every four to six weeks. Two days after a routine catheter change in November 2009, this patient woke up in the morning and noticed that the suprapubic catheter had come out. He went straight to Accident and Emergency. The suprapubic catheter was changed by a health professional and this patient was sent home. But the suprapubic catheter did not drain urine. This patient developed increasing degree of pain and swelling in suprapubic region. He did not pass any urine per urethra. He felt sick and came to spinal unit five hours later. About twenty ml of contrast was injected through suprapubic catheter and X-rays were taken. The suprapubic catheter was patent; the catheter was not blocked. The Foley catheter could be seen going around in a circular manner through the urinary bladder into the urethra. The contrast did not opacify urinary bladder; but proximal urethra was seen. The tip of Foley catheter was lying in proximal urethra. The balloon of Foley catheter had been inflated in urethra. When the balloon of Foley catheter was deflated, this patient developed massive bleeding per urethra. A sterile 22 French Foley catheter was inserted through suprapubic track. The catheter drained bloody urine. He was admitted to spinal unit and received intravenous fluids and meropenem. Haematuria subsided after 48 hours. The patient was discharged home a week later in a stable condition. This case shows that serious complications can occur during

Family satisfaction, pain, and quality-of-life in emerging adults with spina bifida: a longitudinal analysis.

PubMed

Bellin, Melissa H; Dicianno, Brad E; Osteen, Philip; Dosa, Nienke; Aparicio, Elizabeth; Braun, Patricia; Zabel, T Andrew

2013-08-01

This study uses the Life Course Model for Spina Bifida (SB) to advance knowledge of factors associated with change in quality-of-life (QOL) among emerging adults with SB. Forty-eight participants (mean [SD], 22.04 [2.16] yrs) completed self-report questionnaires at two time points, 15 mos apart. Four QOL domains (physical health, psychological, social relationships, and environment) were measured using the World Health Organization QOL-BREF version. SB clinical data were collected via chart reviews. Paired t tests and reliable change indices evaluated group- and individual-level QOL change, respectively. Multiple regression analyses tested the contributions of the Life Course variables in explaining change in QOL over time. No significant group-level differences in the QOL domains were found between time 1 and time 2, but there was substantial individual variation in QOL over time. SB severity was related to a decline only in psychological QOL (B = -0.68, P = 0.02). Increased pain was associated with reduced physical health (B = -0.29, P = 0.049) and psychological (B = -0.29, P = 0.03) QOL at time 2, whereas greater family satisfaction was related to improved QOL in several domains. Clinicians should be aware of the negative impact of pain and the protective influence of family satisfaction on QOL in emerging adults with SB.

Monte Carlo algorithms for Brownian phylogenetic models.

PubMed

Horvilleur, Benjamin; Lartillot, Nicolas

2014-11-01

Brownian models have been introduced in phylogenetics for describing variation in substitution rates through time, with applications to molecular dating or to the comparative analysis of variation in substitution patterns among lineages. Thus far, however, the Monte Carlo implementations of these models have relied on crude approximations, in which the Brownian process is sampled only at the internal nodes of the phylogeny or at the midpoints along each branch, and the unknown trajectory between these sampled points is summarized by simple branchwise average substitution rates. A more accurate Monte Carlo approach is introduced, explicitly sampling a fine-grained discretization of the trajectory of the (potentially multivariate) Brownian process along the phylogeny. Generic Monte Carlo resampling algorithms are proposed for updating the Brownian paths along and across branches. Specific computational strategies are developed for efficient integration of the finite-time substitution probabilities across branches induced by the Brownian trajectory. The mixing properties and the computational complexity of the resulting Markov chain Monte Carlo sampler scale reasonably with the discretization level, allowing practical applications with up to a few hundred discretization points along the entire depth of the tree. The method can be generalized to other Markovian stochastic processes, making it possible to implement a wide range of time-dependent substitution models with well-controlled computational precision. The program is freely available at www.phylobayes.org. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Discrepancies in mother and child perceptions of spina bifida medical responsibilities during the transition to adolescence: associations with family conflict and medical adherence.

PubMed

Psihogios, Alexandra M; Holmbeck, Grayson N

2013-09-01

This study investigated mother-child discrepancies over perceptions of who is responsible for spina bifida (SB) medical tasks in relation to family conflict and medical adherence. 140 youth with SB and their mothers completed questionnaires regarding who is responsible for specific SB medical tasks, family conflict, and medical adherence. An observational measure was also used to assess family conflict. Although children viewed themselves as more responsible for medical management than mothers did, mother-child discrepancies were not associated with family conflict or medical adherence. Interaction effects revealed that adherence was better when family conflict was low and when parents were responsible for medical tasks. Parental involvement in SB medical care is essential for optimal medical adherence during adolescence. The presence of family conflict also plays an influential role on SB medical adherence. Future research should evaluate the relations between discrepancies, family conflict, and medical adherence across time.

High-efficiency wavefunction updates for large scale Quantum Monte Carlo

NASA Astrophysics Data System (ADS)

Kent, Paul; McDaniel, Tyler; Li, Ying Wai; D'Azevedo, Ed

Within ab intio Quantum Monte Carlo (QMC) simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunctions. The evaluation of each Monte Carlo move requires finding the determinant of a dense matrix, which is traditionally iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. For calculations with thousands of electrons, this operation dominates the execution profile. We propose a novel rank- k delayed update scheme. This strategy enables probability evaluation for multiple successive Monte Carlo moves, with application of accepted moves to the matrices delayed until after a predetermined number of moves, k. Accepted events grouped in this manner are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency. This procedure does not change the underlying Monte Carlo sampling or the sampling efficiency. For large systems and algorithms such as diffusion Monte Carlo where the acceptance ratio is high, order of magnitude speedups can be obtained on both multi-core CPU and on GPUs, making this algorithm highly advantageous for current petascale and future exascale computations.

A modified Monte Carlo model for the ionospheric heating rates

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Fontheim, E. G.; Robertson, S. C.

1972-01-01

A Monte Carlo method is adopted as a basis for the derivation of the photoelectron heat input into the ionospheric plasma. This approach is modified in an attempt to minimize the computation time. The heat input distributions are computed for arbitrarily small source elements that are spaced at distances apart corresponding to the photoelectron dissipation range. By means of a nonlinear interpolation procedure their individual heating rate distributions are utilized to produce synthetic ones that fill the gaps between the Monte Carlo generated distributions. By varying these gaps and the corresponding number of Monte Carlo runs the accuracy of the results is tested to verify the validity of this procedure. It is concluded that this model can reduce the computation time by more than a factor of three, thus improving the feasibility of including Monte Carlo calculations in self-consistent ionosphere models.

Implementation of Monte Carlo Dose calculation for CyberKnife treatment planning

NASA Astrophysics Data System (ADS)

Ma, C.-M.; Li, J. S.; Deng, J.; Fan, J.

2008-02-01

Accurate dose calculation is essential to advanced stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) especially for treatment planning involving heterogeneous patient anatomy. This paper describes the implementation of a fast Monte Carlo dose calculation algorithm in SRS/SRT treatment planning for the CyberKnife® SRS/SRT system. A superposition Monte Carlo algorithm is developed for this application. Photon mean free paths and interaction types for different materials and energies as well as the tracks of secondary electrons are pre-simulated using the MCSIM system. Photon interaction forcing and splitting are applied to the source photons in the patient calculation and the pre-simulated electron tracks are repeated with proper corrections based on the tissue density and electron stopping powers. Electron energy is deposited along the tracks and accumulated in the simulation geometry. Scattered and bremsstrahlung photons are transported, after applying the Russian roulette technique, in the same way as the primary photons. Dose calculations are compared with full Monte Carlo simulations performed using EGS4/MCSIM and the CyberKnife treatment planning system (TPS) for lung, head & neck and liver treatments. Comparisons with full Monte Carlo simulations show excellent agreement (within 0.5%). More than 10% differences in the target dose are found between Monte Carlo simulations and the CyberKnife TPS for SRS/SRT lung treatment while negligible differences are shown in head and neck and liver for the cases investigated. The calculation time using our superposition Monte Carlo algorithm is reduced up to 62 times (46 times on average for 10 typical clinical cases) compared to full Monte Carlo simulations. SRS/SRT dose distributions calculated by simple dose algorithms may be significantly overestimated for small lung target volumes, which can be improved by accurate Monte Carlo dose calculations.

Calculating Potential Energy Curves with Quantum Monte Carlo

NASA Astrophysics Data System (ADS)

Powell, Andrew D.; Dawes, Richard

2014-06-01

Quantum Monte Carlo (QMC) is a computational technique that can be applied to the electronic Schrödinger equation for molecules. QMC methods such as Variational Monte Carlo (VMC) and Diffusion Monte Carlo (DMC) have demonstrated the capability of capturing large fractions of the correlation energy, thus suggesting their possible use for high-accuracy quantum chemistry calculations. QMC methods scale particularly well with respect to parallelization making them an attractive consideration in anticipation of next-generation computing architectures which will involve massive parallelization with millions of cores. Due to the statistical nature of the approach, in contrast to standard quantum chemistry methods, uncertainties (error-bars) are associated with each calculated energy. This study focuses on the cost, feasibility and practical application of calculating potential energy curves for small molecules with QMC methods. Trial wave functions were constructed with the multi-configurational self-consistent field (MCSCF) method from GAMESS-US.[1] The CASINO Monte Carlo quantum chemistry package [2] was used for all of the DMC calculations. An overview of our progress in this direction will be given. References: M. W. Schmidt et al. J. Comput. Chem. 14, 1347 (1993). R. J. Needs et al. J. Phys.: Condensed Matter 22, 023201 (2010).

Monte Carlo verification of radiotherapy treatments with CloudMC.

PubMed

Miras, Hector; Jiménez, Rubén; Perales, Álvaro; Terrón, José Antonio; Bertolet, Alejandro; Ortiz, Antonio; Macías, José

2018-06-27

A new implementation has been made on CloudMC, a cloud-based platform presented in a previous work, in order to provide services for radiotherapy treatment verification by means of Monte Carlo in a fast, easy and economical way. A description of the architecture of the application and the new developments implemented is presented together with the results of the tests carried out to validate its performance. CloudMC has been developed over Microsoft Azure cloud. It is based on a map/reduce implementation for Monte Carlo calculations distribution over a dynamic cluster of virtual machines in order to reduce calculation time. CloudMC has been updated with new methods to read and process the information related to radiotherapy treatment verification: CT image set, treatment plan, structures and dose distribution files in DICOM format. Some tests have been designed in order to determine, for the different tasks, the most suitable type of virtual machines from those available in Azure. Finally, the performance of Monte Carlo verification in CloudMC is studied through three real cases that involve different treatment techniques, linac models and Monte Carlo codes. Considering computational and economic factors, D1_v2 and G1 virtual machines were selected as the default type for the Worker Roles and the Reducer Role respectively. Calculation times up to 33 min and costs of 16 € were achieved for the verification cases presented when a statistical uncertainty below 2% (2σ) was required. The costs were reduced to 3-6 € when uncertainty requirements are relaxed to 4%. Advantages like high computational power, scalability, easy access and pay-per-usage model, make Monte Carlo cloud-based solutions, like the one presented in this work, an important step forward to solve the long-lived problem of truly introducing the Monte Carlo algorithms in the daily routine of the radiotherapy planning process.

Libya Montes

NASA Image and Video Library

2002-11-23

This image by NASA Mars Odyssey spacecraft shows the rugged cratered highland region of Libya Montes, which forms part of the rim of an ancient impact basin called Isidis. This region of the highlands is fairly dissected with valley networks. There is still debate within the scientific community as to how valley networks themselves form: surface runoff (rainfall/snowmelt) or headward erosion via groundwater sapping. The degree of dissection here in this region suggests surface runoff rather than groundwater sapping. Small dunes are also visible on the floors of some of these channels. http://photojournal.jpl.nasa.gov/catalog/PIA04008

Exploring cluster Monte Carlo updates with Boltzmann machines

NASA Astrophysics Data System (ADS)

Wang, Lei

2017-11-01

Boltzmann machines are physics informed generative models with broad applications in machine learning. They model the probability distribution of an input data set with latent variables and generate new samples accordingly. Applying the Boltzmann machines back to physics, they are ideal recommender systems to accelerate the Monte Carlo simulation of physical systems due to their flexibility and effectiveness. More intriguingly, we show that the generative sampling of the Boltzmann machines can even give different cluster Monte Carlo algorithms. The latent representation of the Boltzmann machines can be designed to mediate complex interactions and identify clusters of the physical system. We demonstrate these findings with concrete examples of the classical Ising model with and without four-spin plaquette interactions. In the future, automatic searches in the algorithm space parametrized by Boltzmann machines may discover more innovative Monte Carlo updates.

Four decades of implicit Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wollaber, Allan B.

In 1971, Fleck and Cummings derived a system of equations to enable robust Monte Carlo simulations of time-dependent, thermal radiative transfer problems. Denoted the “Implicit Monte Carlo” (IMC) equations, their solution remains the de facto standard of high-fidelity radiative transfer simulations. Over the course of 44 years, their numerical properties have become better understood, and accuracy enhancements, novel acceleration methods, and variance reduction techniques have been suggested. In this review, we rederive the IMC equations—explicitly highlighting assumptions as they are made—and outfit the equations with a Monte Carlo interpretation. We put the IMC equations in context with other approximate formsmore » of the radiative transfer equations and present a new demonstration of their equivalence to another well-used linearization solved with deterministic transport methods for frequency-independent problems. We discuss physical and numerical limitations of the IMC equations for asymptotically small time steps, stability characteristics and the potential of maximum principle violations for large time steps, and solution behaviors in an asymptotically thick diffusive limit. We provide a new stability analysis for opacities with general monomial dependence on temperature. Here, we consider spatial accuracy limitations of the IMC equations and discussion acceleration and variance reduction techniques.« less

jTracker and Monte Carlo Comparison

NASA Astrophysics Data System (ADS)

Selensky, Lauren; SeaQuest/E906 Collaboration

2015-10-01

SeaQuest is designed to observe the characteristics and behavior of `sea-quarks' in a proton by reconstructing them from the subatomic particles produced in a collision. The 120 GeV beam from the main injector collides with a fixed target and then passes through a series of detectors which records information about the particles produced in the collision. However, this data becomes meaningful only after it has been processed, stored, analyzed, and interpreted. Several programs are involved in this process. jTracker (sqerp) reads wire or hodoscope hits and reconstructs the tracks of potential dimuon pairs from a run, and Geant4 Monte Carlo simulates dimuon production and background noise from the beam. During track reconstruction, an event must meet the criteria set by the tracker to be considered a viable dimuon pair; this ensures that relevant data is retained. As a check, a comparison between a new version of jTracker and Monte Carlo was made in order to see how accurately jTracker could reconstruct the events created by Monte Carlo. In this presentation, the results of the inquest and their potential effects on the programming will be shown. This work is supported by U.S. DOE MENP Grant DE-FG02-03ER41243.

Four decades of implicit Monte Carlo

DOE PAGES

Wollaber, Allan B.

2016-02-23

In 1971, Fleck and Cummings derived a system of equations to enable robust Monte Carlo simulations of time-dependent, thermal radiative transfer problems. Denoted the “Implicit Monte Carlo” (IMC) equations, their solution remains the de facto standard of high-fidelity radiative transfer simulations. Over the course of 44 years, their numerical properties have become better understood, and accuracy enhancements, novel acceleration methods, and variance reduction techniques have been suggested. In this review, we rederive the IMC equations—explicitly highlighting assumptions as they are made—and outfit the equations with a Monte Carlo interpretation. We put the IMC equations in context with other approximate formsmore » of the radiative transfer equations and present a new demonstration of their equivalence to another well-used linearization solved with deterministic transport methods for frequency-independent problems. We discuss physical and numerical limitations of the IMC equations for asymptotically small time steps, stability characteristics and the potential of maximum principle violations for large time steps, and solution behaviors in an asymptotically thick diffusive limit. We provide a new stability analysis for opacities with general monomial dependence on temperature. Here, we consider spatial accuracy limitations of the IMC equations and discussion acceleration and variance reduction techniques.« less

Erector spinae plane (ESP) block in the management of post thoracotomy pain syndrome: A case series.

PubMed

Forero, Mauricio; Rajarathinam, Manikandan; Adhikary, Sanjib; Chin, Ki Jinn

2017-10-01

Post thoracotomy pain syndrome (PTPS) remains a common complication of thoracic surgery with significant impact on patients' quality of life. Management usually involves a multidisciplinary approach that includes oral and topical analgesics, performing appropriate interventional techniques, and coordinating additional care such as physiotherapy, psychotherapy and rehabilitation. A variety of interventional procedures have been described to treat PTPS that is inadequately managed with systemic or topical analgesics. Most of these procedures are technically complex and are associated with risks and complications due to the proximity of the targets to neuraxial structures and pleura. The ultrasound-guided erector spinae plane (ESP) block is a novel technique for thoracic analgesia that promises to be a relatively simple and safe alternative to more complex and invasive techniques of neural blockade. We have explored the application of the ESP block in the management of PTPS and report our preliminary experience to illustrate its therapeutic potential. The ESP block was performed in a pain clinic setting in a cohort of 7 patients with PTPS following thoracic surgery with lobectomy or pneumonectomy for lung cancer. The blocks were performed with ultrasound guidance by injecting 20-30mL of ropivacaine, with or without steroid, into a fascial plane between the deep surface of erector spinae muscle and the transverse processes of the thoracic vertebrae. This paraspinal tissue plane is distant from the pleura and the neuraxis, thus minimizing the risk of complications associated with injury to these structures. The patients were followed up by telephone one week after each block and reviewed in the clinic 4-6 weeks later to evaluate the analgesic response as well as the need for further injections and modification to the overall analgesic plan. All the patients had excellent immediate pain relief following each ESP block, and 4 out of the 7 patients experienced prolonged

Intracranial translucency as a sonographic marker for detecting open spina bifida at 11-13+6 weeks scan: Our experience.

PubMed

Teegala, Madhavi L; Vinayak, Dhamangaonkar G

2017-01-01

The fourth ventricle, seen as intracranial translucency (IT) at 11-13 +6 weeks, has been reported to be obliterated in cases of open spina bifida (OSB). Our aim was to assess its role in detecting OSB at 11-13 +6 weeks. This prospective study was conducted at foetal medicine unit from January 2014 to June 2015. All women who underwent both first and mid-trimester scan in our unit were included in the study. IT was categorized as normal, obliterated or not clear. Spine was examined during both scans. Totally, 341 cases were included in the study. IT was found to be obliterated in four cases and not clear in one case. There was demonstrable OSB at 11-13 +6 weeks in two cases, at 15-16 weeks in two cases and at 24 weeks in one case. In the remaining 336 cases with normal IT, spine was found to be normal at target scan. Mid-sagittal view of face that is routinely used to measure nuchal translucency (NT) can also be used to detect OSB. It is feasible to integrate IT into the routine 11-13 +6 weeks scan.

Monte Carlo Particle Lists: MCPL

NASA Astrophysics Data System (ADS)

Kittelmann, T.; Klinkby, E.; Knudsen, E. B.; Willendrup, P.; Cai, X. X.; Kanaki, K.

2017-09-01

A binary format with lists of particle state information, for interchanging particles between various Monte Carlo simulation applications, is presented. Portable C code for file manipulation is made available to the scientific community, along with converters and plugins for several popular simulation packages.

NOTE: Monte Carlo evaluation of kerma in an HDR brachytherapy bunker

NASA Astrophysics Data System (ADS)

Pérez-Calatayud, J.; Granero, D.; Ballester, F.; Casal, E.; Crispin, V.; Puchades, V.; León, A.; Verdú, G.

2004-12-01

In recent years, the use of high dose rate (HDR) after-loader machines has greatly increased due to the shift from traditional Cs-137/Ir-192 low dose rate (LDR) to HDR brachytherapy. The method used to calculate the required concrete and, where appropriate, lead shielding in the door is based on analytical methods provided by documents published by the ICRP, the IAEA and the NCRP. The purpose of this study is to perform a more realistic kerma evaluation at the entrance maze door of an HDR bunker using the Monte Carlo code GEANT4. The Monte Carlo results were validated experimentally. The spectrum at the maze entrance door, obtained with Monte Carlo, has an average energy of about 110 keV, maintaining a similar value along the length of the maze. The comparison of results from the aforementioned values with the Monte Carlo ones shows that results obtained using the albedo coefficient from the ICRP document more closely match those given by the Monte Carlo method, although the maximum value given by MC calculations is 30% greater.

Monte Carlo Calculations of Polarized Microwave Radiation Emerging from Cloud Structures

NASA Technical Reports Server (NTRS)

Kummerow, Christian; Roberti, Laura

1998-01-01

The last decade has seen tremendous growth in cloud dynamical and microphysical models that are able to simulate storms and storm systems with very high spatial resolution, typically of the order of a few kilometers. The fairly realistic distributions of cloud and hydrometeor properties that these models generate has in turn led to a renewed interest in the three-dimensional microwave radiative transfer modeling needed to understand the effect of cloud and rainfall inhomogeneities upon microwave observations. Monte Carlo methods, and particularly backwards Monte Carlo methods have shown themselves to be very desirable due to the quick convergence of the solutions. Unfortunately, backwards Monte Carlo methods are not well suited to treat polarized radiation. This study reviews the existing Monte Carlo methods and presents a new polarized Monte Carlo radiative transfer code. The code is based on a forward scheme but uses aliasing techniques to keep the computational requirements equivalent to the backwards solution. Radiative transfer computations have been performed using a microphysical-dynamical cloud model and the results are presented together with the algorithm description.

TH-E-18A-01: Developments in Monte Carlo Methods for Medical Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Badal, A; Zbijewski, W; Bolch, W

Monte Carlo simulation methods are widely used in medical physics research and are starting to be implemented in clinical applications such as radiation therapy planning systems. Monte Carlo simulations offer the capability to accurately estimate quantities of interest that are challenging to measure experimentally while taking into account the realistic anatomy of an individual patient. Traditionally, practical application of Monte Carlo simulation codes in diagnostic imaging was limited by the need for large computational resources or long execution times. However, recent advancements in high-performance computing hardware, combined with a new generation of Monte Carlo simulation algorithms and novel postprocessing methods,more » are allowing for the computation of relevant imaging parameters of interest such as patient organ doses and scatter-to-primaryratios in radiographic projections in just a few seconds using affordable computational resources. Programmable Graphics Processing Units (GPUs), for example, provide a convenient, affordable platform for parallelized Monte Carlo executions that yield simulation times on the order of 10{sup 7} xray/ s. Even with GPU acceleration, however, Monte Carlo simulation times can be prohibitive for routine clinical practice. To reduce simulation times further, variance reduction techniques can be used to alter the probabilistic models underlying the x-ray tracking process, resulting in lower variance in the results without biasing the estimates. Other complementary strategies for further reductions in computation time are denoising of the Monte Carlo estimates and estimating (scoring) the quantity of interest at a sparse set of sampling locations (e.g. at a small number of detector pixels in a scatter simulation) followed by interpolation. Beyond reduction of the computational resources required for performing Monte Carlo simulations in medical imaging, the use of accurate representations of patient anatomy is crucial to

Quasi-Monte Carlo Methods Applied to Tau-Leaping in Stochastic Biological Systems.

PubMed

Beentjes, Casper H L; Baker, Ruth E

2018-05-25

Quasi-Monte Carlo methods have proven to be effective extensions of traditional Monte Carlo methods in, amongst others, problems of quadrature and the sample path simulation of stochastic differential equations. By replacing the random number input stream in a simulation procedure by a low-discrepancy number input stream, variance reductions of several orders have been observed in financial applications. Analysis of stochastic effects in well-mixed chemical reaction networks often relies on sample path simulation using Monte Carlo methods, even though these methods suffer from typical slow [Formula: see text] convergence rates as a function of the number of sample paths N. This paper investigates the combination of (randomised) quasi-Monte Carlo methods with an efficient sample path simulation procedure, namely [Formula: see text]-leaping. We show that this combination is often more effective than traditional Monte Carlo simulation in terms of the decay of statistical errors. The observed convergence rate behaviour is, however, non-trivial due to the discrete nature of the models of chemical reactions. We explain how this affects the performance of quasi-Monte Carlo methods by looking at a test problem in standard quadrature.

NUEN-618 Class Project: Actually Implicit Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vega, R. M.; Brunner, T. A.

2017-12-14

This research describes a new method for the solution of the thermal radiative transfer (TRT) equations that is implicit in time which will be called Actually Implicit Monte Carlo (AIMC). This section aims to introduce the TRT equations, as well as the current workhorse method which is known as Implicit Monte Carlo (IMC). As the name of the method proposed here indicates, IMC is a misnomer in that it is only semi-implicit, which will be shown in this section as well.

Discrepancies in Mother and Child Perceptions of Spina Bifida Medical Responsibilities During the Transition to Adolescence: Associations With Family Conflict and Medical Adherence

PubMed Central

Psihogios, Alexandra M.

2013-01-01

Objective This study investigated mother–child discrepancies over perceptions of who is responsible for spina bifida (SB) medical tasks in relation to family conflict and medical adherence. Method 140 youth with SB and their mothers completed questionnaires regarding who is responsible for specific SB medical tasks, family conflict, and medical adherence. An observational measure was also used to assess family conflict. Results Although children viewed themselves as more responsible for medical management than mothers did, mother–child discrepancies were not associated with family conflict or medical adherence. Interaction effects revealed that adherence was better when family conflict was low and when parents were responsible for medical tasks. Conclusions Parental involvement in SB medical care is essential for optimal medical adherence during adolescence. The presence of family conflict also plays an influential role on SB medical adherence. Future research should evaluate the relations between discrepancies, family conflict, and medical adherence across time. PMID:23843631

Observed Macro- and Micro-Level Parenting Behaviors During Preadolescent Family Interactions as Predictors of Adjustment in Emerging Adults With and Without Spina Bifida

PubMed Central

Amaro, Christina M.; Devine, Katie A.; Psihogios, Alexandra M.; Murphy, Lexa K.; Holmbeck, Grayson N.

2015-01-01

Objective To examine observed autonomy-promoting and -inhibiting parenting behaviors during preadolescence as predictors of adjustment outcomes in emerging adults with and without spina bifida (SB). Methods Demographic and videotaped interaction data were collected from families with 8/9-year-old children with SB (n = 68) and a matched group of typically developing youth (n = 68). Observed interaction data were coded with macro- and micro-coding schemes. Measures of emerging adulthood adjustment were collected 10 years later (ages 18/19 years; n = 50 and n = 60 for SB and comparison groups, respectively). Results Autonomy-promoting (behavioral control, autonomy-relatedness) and -inhibiting (psychological control) observed preadolescent parenting behaviors prospectively predicted emerging adulthood adjustment, particularly within educational, social, and emotional domains. Interestingly, high parent undermining of relatedness predicted better educational and social adjustment in the SB sample. Conclusions Parenting behaviors related to autonomy have long-term consequences for adjustment in emerging adults with and without SB. PMID:24864277

Geometry and Dynamics for Markov Chain Monte Carlo

NASA Astrophysics Data System (ADS)

Barp, Alessandro; Briol, François-Xavier; Kennedy, Anthony D.; Girolami, Mark

2018-03-01

Markov Chain Monte Carlo methods have revolutionised mathematical computation and enabled statistical inference within many previously intractable models. In this context, Hamiltonian dynamics have been proposed as an efficient way of building chains which can explore probability densities efficiently. The method emerges from physics and geometry and these links have been extensively studied by a series of authors through the last thirty years. However, there is currently a gap between the intuitions and knowledge of users of the methodology and our deep understanding of these theoretical foundations. The aim of this review is to provide a comprehensive introduction to the geometric tools used in Hamiltonian Monte Carlo at a level accessible to statisticians, machine learners and other users of the methodology with only a basic understanding of Monte Carlo methods. This will be complemented with some discussion of the most recent advances in the field which we believe will become increasingly relevant to applied scientists.

Tool for Rapid Analysis of Monte Carlo Simulations

NASA Technical Reports Server (NTRS)

Restrepo, Carolina; McCall, Kurt E.; Hurtado, John E.

2011-01-01

Designing a spacecraft, or any other complex engineering system, requires extensive simulation and analysis work. Oftentimes, the large amounts of simulation data generated are very di cult and time consuming to analyze, with the added risk of overlooking potentially critical problems in the design. The authors have developed a generic data analysis tool that can quickly sort through large data sets and point an analyst to the areas in the data set that cause specific types of failures. The Tool for Rapid Analysis of Monte Carlo simulations (TRAM) has been used in recent design and analysis work for the Orion vehicle, greatly decreasing the time it takes to evaluate performance requirements. A previous version of this tool was developed to automatically identify driving design variables in Monte Carlo data sets. This paper describes a new, parallel version, of TRAM implemented on a graphical processing unit, and presents analysis results for NASA's Orion Monte Carlo data to demonstrate its capabilities.

Monte Carlo tests of the ELIPGRID-PC algorithm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, J.R.

1995-04-01

The standard tool for calculating the probability of detecting pockets of contamination called hot spots has been the ELIPGRID computer code of Singer and Wickman. The ELIPGRID-PC program has recently made this algorithm available for an IBM{reg_sign} PC. However, no known independent validation of the ELIPGRID algorithm exists. This document describes a Monte Carlo simulation-based validation of a modified version of the ELIPGRID-PC code. The modified ELIPGRID-PC code is shown to match Monte Carlo-calculated hot-spot detection probabilities to within {plus_minus}0.5% for 319 out of 320 test cases. The one exception, a very thin elliptical hot spot located within a rectangularmore » sampling grid, differed from the Monte Carlo-calculated probability by about 1%. These results provide confidence in the ability of the modified ELIPGRID-PC code to accurately predict hot-spot detection probabilities within an acceptable range of error.« less

Two proposed convergence criteria for Monte Carlo solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forster, R.A.; Pederson, S.P.; Booth, T.E.

1992-01-01

The central limit theorem (CLT) can be applied to a Monte Carlo solution if two requirements are satisfied: (1) The random variable has a finite mean and a finite variance; and (2) the number N of independent observations grows large. When these two conditions are satisfied, a confidence interval (CI) based on the normal distribution with a specified coverage probability can be formed. The first requirement is generally satisfied by the knowledge of the Monte Carlo tally being used. The Monte Carlo practitioner has a limited number of marginal methods to assess the fulfillment of the second requirement, such asmore » statistical error reduction proportional to 1/[radical]N with error magnitude guidelines. Two proposed methods are discussed in this paper to assist in deciding if N is large enough: estimating the relative variance of the variance (VOV) and examining the empirical history score probability density function (pdf).« less

Venus - Lakshmi Planum and Maxwell Montes

NASA Image and Video Library

1996-03-07

This full resolution radar image from NASA Magellan spacecraft is centered along the eastern edge of Lakshmi Planum and the western edge of Maxwell Montes. http://photojournal.jpl.nasa.gov/catalog/PIA00241

Prospective detection of open spina bifida at 11-13 weeks by assessing intracranial translucency and posterior brain.

PubMed

Chaoui, R; Benoit, B; Heling, K S; Kagan, K O; Pietzsch, V; Sarut Lopez, A; Tekesin, I; Karl, K

2011-12-01

We describe a case series of six fetuses with open spina bifida (OSB) from four different prenatal units, where the anomaly was detected at the routine 11-13-week ultrasound examination. Crown-rump length ranged from 49 to 78 mm. All cases were first suspected during nuchal translucency thickness measurement in the mid-sagittal plane of the face. OSB was lumbosacral in five fetuses and cervical in one. The intracranial translucency (IT) was obliterated in two cases, but some fluid was found in the other four cases. However, in all cases the typical landmarks of a normal posterior brain and normal IT were absent. In all six cases the ratio of brainstem diameter to brainstem-occipital bone distance was increased (≥ 1). This detection of an abnormal posterior brain led to a targeted examination and detection of the spinal lesion during the same examination in five cases, whereas in one suspicious case the patient was recalled at 17 weeks, when the abnormality was detected. Two fetuses had both multiple anomalies and trisomy 18. These prospective cases demonstrate the feasibility of using the standard mid-sagittal plane commonly used for NT measurement to assess the IT and the posterior brain and to determine the presence of OSB during NT screening. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.

Generation of Induced Pluripotent Stem Cells and Neural Stem/Progenitor Cells from Newborns with Spina Bifida Aperta.

PubMed

Bamba, Yohei; Nonaka, Masahiro; Sasaki, Natsu; Shofuda, Tomoko; Kanematsu, Daisuke; Suemizu, Hiroshi; Higuchi, Yuichiro; Pooh, Ritsuko K; Kanemura, Yonehiro; Okano, Hideyuki; Yamasaki, Mami

2017-12-01

We established induced pluripotent stem cells (iPSCs) and neural stem/progenitor cells (NSPCs) from three newborns with spina bifida aperta (SBa) using clinically practical methods. We aimed to develop stem cell lines derived from newborns with SBa for future therapeutic use. SBa is a common congenital spinal cord abnormality that causes defects in neurological and urological functions. Stem cell transplantation therapies are predicted to provide beneficial effects for patients with SBa. However, the availability of appropriate cell sources is inadequate for clinical use because of their limited accessibility and expandability, as well as ethical issues. Fibroblast cultures were established from small fragments of skin obtained from newborns with SBa during SBa repair surgery. The cultured cells were transfected with episomal plasmid vectors encoding reprogramming factors necessary for generating iPSCs. These cells were then differentiated into NSPCs by chemical compound treatment, and NSPCs were expanded using neurosphere technology. We successfully generated iPSC lines from the neonatal dermal fibroblasts of three newborns with SBa. We confirmed that these lines exhibited the characteristics of human pluripotent stem cells. We successfully generated NSPCs from all SBa newborn-derived iPSCs with a combination of neural induction and neurosphere technology. We successfully generated iPSCs and iPSC-NSPCs from surgical samples obtained from newborns with SBa with the goal of future clinical use in patients with SBa.

Fixed forced detection for fast SPECT Monte-Carlo simulation

NASA Astrophysics Data System (ADS)

Cajgfinger, T.; Rit, S.; Létang, J. M.; Halty, A.; Sarrut, D.

2018-03-01

Monte-Carlo simulations of SPECT images are notoriously slow to converge due to the large ratio between the number of photons emitted and detected in the collimator. This work proposes a method to accelerate the simulations based on fixed forced detection (FFD) combined with an analytical response of the detector. FFD is based on a Monte-Carlo simulation but forces the detection of a photon in each detector pixel weighted by the probability of emission (or scattering) and transmission to this pixel. The method was evaluated with numerical phantoms and on patient images. We obtained differences with analog Monte Carlo lower than the statistical uncertainty. The overall computing time gain can reach up to five orders of magnitude. Source code and examples are available in the Gate V8.0 release.

Fixed forced detection for fast SPECT Monte-Carlo simulation.

PubMed

Cajgfinger, T; Rit, S; Létang, J M; Halty, A; Sarrut, D

2018-03-02

Monte-Carlo simulations of SPECT images are notoriously slow to converge due to the large ratio between the number of photons emitted and detected in the collimator. This work proposes a method to accelerate the simulations based on fixed forced detection (FFD) combined with an analytical response of the detector. FFD is based on a Monte-Carlo simulation but forces the detection of a photon in each detector pixel weighted by the probability of emission (or scattering) and transmission to this pixel. The method was evaluated with numerical phantoms and on patient images. We obtained differences with analog Monte Carlo lower than the statistical uncertainty. The overall computing time gain can reach up to five orders of magnitude. Source code and examples are available in the Gate V8.0 release.

Monte Carlo treatment planning with modulated electron radiotherapy: framework development and application

NASA Astrophysics Data System (ADS)

Alexander, Andrew William

Within the field of medical physics, Monte Carlo radiation transport simulations are considered to be the most accurate method for the determination of dose distributions in patients. The McGill Monte Carlo treatment planning system (MMCTP), provides a flexible software environment to integrate Monte Carlo simulations with current and new treatment modalities. A developing treatment modality called energy and intensity modulated electron radiotherapy (MERT) is a promising modality, which has the fundamental capabilities to enhance the dosimetry of superficial targets. An objective of this work is to advance the research and development of MERT with the end goal of clinical use. To this end, we present the MMCTP system with an integrated toolkit for MERT planning and delivery of MERT fields. Delivery is achieved using an automated "few leaf electron collimator" (FLEC) and a controller. Aside from the MERT planning toolkit, the MMCTP system required numerous add-ons to perform the complex task of large-scale autonomous Monte Carlo simulations. The first was a DICOM import filter, followed by the implementation of DOSXYZnrc as a dose calculation engine and by logic methods for submitting and updating the status of Monte Carlo simulations. Within this work we validated the MMCTP system with a head and neck Monte Carlo recalculation study performed by a medical dosimetrist. The impact of MMCTP lies in the fact that it allows for systematic and platform independent large-scale Monte Carlo dose calculations for different treatment sites and treatment modalities. In addition to the MERT planning tools, various optimization algorithms were created external to MMCTP. The algorithms produced MERT treatment plans based on dose volume constraints that employ Monte Carlo pre-generated patient-specific kernels. The Monte Carlo kernels are generated from patient-specific Monte Carlo dose distributions within MMCTP. The structure of the MERT planning toolkit software and

Fast quantum Monte Carlo on a GPU

NASA Astrophysics Data System (ADS)

Lutsyshyn, Y.

2015-02-01

We present a scheme for the parallelization of quantum Monte Carlo method on graphical processing units, focusing on variational Monte Carlo simulation of bosonic systems. We use asynchronous execution schemes with shared memory persistence, and obtain an excellent utilization of the accelerator. The CUDA code is provided along with a package that simulates liquid helium-4. The program was benchmarked on several models of Nvidia GPU, including Fermi GTX560 and M2090, and the Kepler architecture K20 GPU. Special optimization was developed for the Kepler cards, including placement of data structures in the register space of the Kepler GPUs. Kepler-specific optimization is discussed.

Diagnosing Undersampling Biases in Monte Carlo Eigenvalue and Flux Tally Estimates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perfetti, Christopher M.; Rearden, Bradley T.; Marshall, William J.

2017-02-08

Here, this study focuses on understanding the phenomena in Monte Carlo simulations known as undersampling, in which Monte Carlo tally estimates may not encounter a sufficient number of particles during each generation to obtain unbiased tally estimates. Steady-state Monte Carlo simulations were performed using the KENO Monte Carlo tools within the SCALE code system for models of several burnup credit applications with varying degrees of spatial and isotopic complexities, and the incidence and impact of undersampling on eigenvalue and flux estimates were examined. Using an inadequate number of particle histories in each generation was found to produce a maximum bias of ~100 pcm in eigenvalue estimates and biases that exceeded 10% in fuel pin flux tally estimates. Having quantified the potential magnitude of undersampling biases in eigenvalue and flux tally estimates in these systems, this study then investigated whether Markov Chain Monte Carlo convergence metrics could be integrated into Monte Carlo simulations to predict the onset and magnitude of undersampling biases. Five potential metrics for identifying undersampling biases were implemented in the SCALE code system and evaluated for their ability to predict undersampling biases by comparing the test metric scores with the observed undersampling biases. Finally, of the five convergence metrics that were investigated, three (the Heidelberger-Welch relative half-width, the Gelman-Rubin more » $$\\hat{R}_c$$ diagnostic, and tally entropy) showed the potential to accurately predict the behavior of undersampling biases in the responses examined.« less

Dunes in Nectaris Montes

NASA Image and Video Library

2018-05-14

This image from NASA's Mars Reconnaissance Orbiter (MRO) shows some of these on the slopes of Nectaris Montes within Coprates Chasma. Sand dunes in Valles Marineris can be impressive in size, with steep slopes that seem to climb and descend. The brighter bedforms are inactive while the bigger dunes move over the landscape, burying and exhuming the surface. https://photojournal.jpl.nasa.gov/catalog/PIA22455

Accuracy of Monte Carlo simulations compared to in-vivo MDCT dosimetry.

PubMed

Bostani, Maryam; Mueller, Jonathon W; McMillan, Kyle; Cody, Dianna D; Cagnon, Chris H; DeMarco, John J; McNitt-Gray, Michael F

2015-02-01

The purpose of this study was to assess the accuracy of a Monte Carlo simulation-based method for estimating radiation dose from multidetector computed tomography (MDCT) by comparing simulated doses in ten patients to in-vivo dose measurements. MD Anderson Cancer Center Institutional Review Board approved the acquisition of in-vivo rectal dose measurements in a pilot study of ten patients undergoing virtual colonoscopy. The dose measurements were obtained by affixing TLD capsules to the inner lumen of rectal catheters. Voxelized patient models were generated from the MDCT images of the ten patients, and the dose to the TLD for all exposures was estimated using Monte Carlo based simulations. The Monte Carlo simulation results were compared to the in-vivo dose measurements to determine accuracy. The calculated mean percent difference between TLD measurements and Monte Carlo simulations was -4.9% with standard deviation of 8.7% and a range of -22.7% to 5.7%. The results of this study demonstrate very good agreement between simulated and measured doses in-vivo. Taken together with previous validation efforts, this work demonstrates that the Monte Carlo simulation methods can provide accurate estimates of radiation dose in patients undergoing CT examinations.

75 FR 13560 - Disease, Disability, and Injury Prevention and Control Special Emphasis Panel (SEP): RFA DD 10...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-22

... Research on Spina Bifida, RFA DD 10-003 Public Health Research on Children and Adults Living With Spina... Progression in Young Children With Spina Bifida,and RFA DP 10-006 Epidemiologic Study of Inflammatory Bowel... Health Research on Children and Adults Living with Spina Bifida, RFA DD 10-004 Developing a Prospective...

Analytical Applications of Monte Carlo Techniques.

ERIC Educational Resources Information Center

Guell, Oscar A.; Holcombe, James A.

1990-01-01

Described are analytical applications of the theory of random processes, in particular solutions obtained by using statistical procedures known as Monte Carlo techniques. Supercomputer simulations, sampling, integration, ensemble, annealing, and explicit simulation are discussed. (CW)

Estimate of the potential impact of folic acid fortification of corn masa flour on the prevention of neural tube defects.

PubMed

Tinker, Sarah C; Devine, Owen; Mai, Cara; Hamner, Heather C; Reefhuis, Jennita; Gilboa, Suzanne M; Dowling, Nicole F; Honein, Margaret A

2013-10-01

Hispanics in the US have a higher prevalence of neural tube defect (NTD) -affected pregnancies than non-Hispanic whites, and lower median total folic acid (FA) intake. FA fortification of corn masa flour (CMF) is a policy-level intervention for NTD prevention; however, the impact on NTD prevalence has not been estimated. We developed a model to estimate the percentage reduction in prevalence of spina bifida and anencephaly (NTDs) that could occur with FA fortification of CMF. Model inputs included estimates of the percentage reduction in United States NTD prevalence attributed to FA fortification of enriched cereal grain products (1995-1996 vs. 1998-2002), the increase in median FA intake after enriched cereal grain product fortification, and the estimated increase in median FA intake that could occur with CMF fortification at the same level as enriched cereal grain products (140 μg/100 g). We used Monte Carlo simulation to quantify uncertainty. We stratified analyses by racial/ethnic group and rounded results to the nearest 10. We estimated CMF fortification could prevent 30 Hispanic infants from having spina bifida (95% uncertainty interval: 0, 80) and 10 infants from having anencephaly (95% uncertainty interval: 0, 40) annually. The estimated impact among non-Hispanic whites and blacks was smaller. CMF fortification with FA could prevent from 0 to 120 infants, with the most likely value of approximately 40, from having spina bifida or anencephaly among Hispanics, the population most likely to benefit from the proposed intervention. While this estimated reduction is unlikely to be discernible using current birth defect surveillance methods, it still suggests an important benefit to the target population. Copyright © 2013 Wiley Periodicals, Inc.

Monte Carlo: in the beginning and some great expectations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Metropolis, N.

1985-01-01

The central theme will be on the historical setting and origins of the Monte Carlo Method. The scene was post-war Los Alamos Scientific Laboratory. There was an inevitability about the Monte Carlo Event: the ENIAC had recently enjoyed its meteoric rise (on a classified Los Alamos problem); Stan Ulam had returned to Los Alamos; John von Neumann was a frequent visitor. Techniques, algorithms, and applications developed rapidly at Los Alamos. Soon, the fascination of the Method reached wider horizons. The first paper was submitted for publication in the spring of 1949. In the summer of 1949, the first open conferencemore » was held at the University of California at Los Angeles. Of some interst perhaps is an account of Fermi's earlier, independent application in neutron moderation studies while at the University of Rome. The quantum leap expected with the advent of massively parallel processors will provide stimuli for very ambitious applications of the Monte Carlo Method in disciplines ranging from field theories to cosmology, including more realistic models in the neurosciences. A structure of multi-instruction sets for parallel processing is ideally suited for the Monte Carlo approach. One may even hope for a modest hardening of the soft sciences.« less

SU-E-T-188: Film Dosimetry Verification of Monte Carlo Generated Electron Treatment Plans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Enright, S; Asprinio, A; Lu, L

2014-06-01

Purpose: The purpose of this study was to compare dose distributions from film measurements to Monte Carlo generated electron treatment plans. Irradiation with electrons offers the advantages of dose uniformity in the target volume and of minimizing the dose to deeper healthy tissue. Using the Monte Carlo algorithm will improve dose accuracy in regions with heterogeneities and irregular surfaces. Methods: Dose distributions from GafChromic{sup ™} EBT3 films were compared to dose distributions from the Electron Monte Carlo algorithm in the Eclipse{sup ™} radiotherapy treatment planning system. These measurements were obtained for 6MeV, 9MeV and 12MeV electrons at two depths. Allmore » phantoms studied were imported into Eclipse by CT scan. A 1 cm thick solid water template with holes for bonelike and lung-like plugs was used. Different configurations were used with the different plugs inserted into the holes. Configurations with solid-water plugs stacked on top of one another were also used to create an irregular surface. Results: The dose distributions measured from the film agreed with those from the Electron Monte Carlo treatment plan. Accuracy of Electron Monte Carlo algorithm was also compared to that of Pencil Beam. Dose distributions from Monte Carlo had much higher pass rates than distributions from Pencil Beam when compared to the film. The pass rate for Monte Carlo was in the 80%–99% range, where the pass rate for Pencil Beam was as low as 10.76%. Conclusion: The dose distribution from Monte Carlo agreed with the measured dose from the film. When compared to the Pencil Beam algorithm, pass rates for Monte Carlo were much higher. Monte Carlo should be used over Pencil Beam for regions with heterogeneities and irregular surfaces.« less

Inadvertent positioning of suprapubic catheter in urethra: a serious complication during change of suprapubic cystostomy in a spina bifida patient - a case report

PubMed Central

2009-01-01

Introduction Spinal cord injury patients are at risk for developing unusual complications such as autonomic dysreflexia while changing suprapubic cystostomy. We report a male patient with spina bifida in whom the Foley catheter was placed in the urethra during change of suprapubic cystostomy with serious consequences. Case presentation A male patient, born in 1972 with spina bifida and paraplaegia, underwent suprapubic cystostomy in 2003 because of increasing problems with urethral catheter. The patient would come to spinal unit for change of suprapubic catheter every four to six weeks. Two days after a routine catheter change in November 2009, this patient woke up in the morning and noticed that the suprapubic catheter had come out. He went straight to Accident and Emergency. The suprapubic catheter was changed by a health professional and this patient was sent home. But the suprapubic catheter did not drain urine. This patient developed increasing degree of pain and swelling in suprapubic region. He did not pass any urine per urethra. He felt sick and came to spinal unit five hours later. About twenty ml of contrast was injected through suprapubic catheter and X-rays were taken. The suprapubic catheter was patent; the catheter was not blocked. The Foley catheter could be seen going around in a circular manner through the urinary bladder into the urethra. The contrast did not opacify urinary bladder; but proximal urethra was seen. The tip of Foley catheter was lying in proximal urethra. The balloon of Foley catheter had been inflated in urethra. When the balloon of Foley catheter was deflated, this patient developed massive bleeding per urethra. A sterile 22 French Foley catheter was inserted through suprapubic track. The catheter drained bloody urine. He was admitted to spinal unit and received intravenous fluids and meropenem. Haematuria subsided after 48 hours. The patient was discharged home a week later in a stable condition. Conclusion This case shows that

Multiple-time-stepping generalized hybrid Monte Carlo methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Escribano, Bruno, E-mail: bescribano@bcamath.org; Akhmatskaya, Elena; IKERBASQUE, Basque Foundation for Science, E-48013 Bilbao

2015-01-01

Performance of the generalized shadow hybrid Monte Carlo (GSHMC) method [1], which proved to be superior in sampling efficiency over its predecessors [2–4], molecular dynamics and hybrid Monte Carlo, can be further improved by combining it with multi-time-stepping (MTS) and mollification of slow forces. We demonstrate that the comparatively simple modifications of the method not only lead to better performance of GSHMC itself but also allow for beating the best performed methods, which use the similar force splitting schemes. In addition we show that the same ideas can be successfully applied to the conventional generalized hybrid Monte Carlo method (GHMC).more » The resulting methods, MTS-GHMC and MTS-GSHMC, provide accurate reproduction of thermodynamic and dynamical properties, exact temperature control during simulation and computational robustness and efficiency. MTS-GHMC uses a generalized momentum update to achieve weak stochastic stabilization to the molecular dynamics (MD) integrator. MTS-GSHMC adds the use of a shadow (modified) Hamiltonian to filter the MD trajectories in the HMC scheme. We introduce a new shadow Hamiltonian formulation adapted to force-splitting methods. The use of such Hamiltonians improves the acceptance rate of trajectories and has a strong impact on the sampling efficiency of the method. Both methods were implemented in the open-source MD package ProtoMol and were tested on a water and a protein systems. Results were compared to those obtained using a Langevin Molly (LM) method [5] on the same systems. The test results demonstrate the superiority of the new methods over LM in terms of stability, accuracy and sampling efficiency. This suggests that putting the MTS approach in the framework of hybrid Monte Carlo and using the natural stochasticity offered by the generalized hybrid Monte Carlo lead to improving stability of MTS and allow for achieving larger step sizes in the simulation of complex systems.« less

Markov Chain Monte Carlo Methods for Bayesian Data Analysis in Astronomy

NASA Astrophysics Data System (ADS)

Sharma, Sanjib

2017-08-01

Markov Chain Monte Carlo based Bayesian data analysis has now become the method of choice for analyzing and interpreting data in almost all disciplines of science. In astronomy, over the last decade, we have also seen a steady increase in the number of papers that employ Monte Carlo based Bayesian analysis. New, efficient Monte Carlo based methods are continuously being developed and explored. In this review, we first explain the basics of Bayesian theory and discuss how to set up data analysis problems within this framework. Next, we provide an overview of various Monte Carlo based methods for performing Bayesian data analysis. Finally, we discuss advanced ideas that enable us to tackle complex problems and thus hold great promise for the future. We also distribute downloadable computer software (available at https://github.com/sanjibs/bmcmc/ ) that implements some of the algorithms and examples discussed here.

Monte Carlos of the new generation: status and progress

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frixione, Stefano

2005-03-22

Standard parton shower monte carlos are designed to give reliable descriptions of low-pT physics. In the very high-energy regime of modern colliders, this is may lead to largely incorrect predictions of the basic reaction processes. This motivated the recent theoretical efforts aimed at improving monte carlos through the inclusion of matrix elements computed beyond the leading order in QCD. I briefly review the progress made, and discuss bottom production at the Tevatron.

Testing the Utility of a Bio-Neuropsychosocial Model for Predicting Medical Adherence and Responsibility During Early Adolescence in Youth With Spina Bifida.

PubMed

Psihogios, Alexandra M; Murray, Caitlin; Zebracki, Kathy; Acevedo, Laura; Holmbeck, Grayson N

2017-10-01

The present longitudinal, multi-method, and multi-informant study examined biological, neuropsychological, and social predictors of medical adherence and responsibility among early adolescents with spina bifida (SB). Youth with SB (M age = 11.40 at Time 1) and their parents and teachers completed surveys, and families and peers completed observational assessments, at two biennial data collection time points (n = 112 for both time points). Multinomial logistic regressions tested predictors of group membership (adherent vs. nonadherent and child responsible vs. not responsible with SB medical tasks). Consistent with the bio-neuropsychosocial model, several risk factors emerged for SB management. Impaired gross motor classification and low IQ were barriers to obtaining medical responsibility, and high family stress and executive dysfunction were barriers to adherence and responsibility. This study offered intervention targets to promote self-management and adherence for youth with SB and their families, including parent stress-management and family problem-solving. © The Author 2016. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Accurately modeling Gaussian beam propagation in the context of Monte Carlo techniques

NASA Astrophysics Data System (ADS)

Hokr, Brett H.; Winblad, Aidan; Bixler, Joel N.; Elpers, Gabriel; Zollars, Byron; Scully, Marlan O.; Yakovlev, Vladislav V.; Thomas, Robert J.

2016-03-01

Monte Carlo simulations are widely considered to be the gold standard for studying the propagation of light in turbid media. However, traditional Monte Carlo methods fail to account for diffraction because they treat light as a particle. This results in converging beams focusing to a point instead of a diffraction limited spot, greatly effecting the accuracy of Monte Carlo simulations near the focal plane. Here, we present a technique capable of simulating a focusing beam in accordance to the rules of Gaussian optics, resulting in a diffraction limited focal spot. This technique can be easily implemented into any traditional Monte Carlo simulation allowing existing models to be converted to include accurate focusing geometries with minimal effort. We will present results for a focusing beam in a layered tissue model, demonstrating that for different scenarios the region of highest intensity, thus the greatest heating, can change from the surface to the focus. The ability to simulate accurate focusing geometries will greatly enhance the usefulness of Monte Carlo for countless applications, including studying laser tissue interactions in medical applications and light propagation through turbid media.

Fission matrix-based Monte Carlo criticality analysis of fuel storage pools

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farlotti, M.; Ecole Polytechnique, Palaiseau, F 91128; Larsen, E. W.

2013-07-01

Standard Monte Carlo transport procedures experience difficulties in solving criticality problems in fuel storage pools. Because of the strong neutron absorption between fuel assemblies, source convergence can be very slow, leading to incorrect estimates of the eigenvalue and the eigenfunction. This study examines an alternative fission matrix-based Monte Carlo transport method that takes advantage of the geometry of a storage pool to overcome this difficulty. The method uses Monte Carlo transport to build (essentially) a fission matrix, which is then used to calculate the criticality and the critical flux. This method was tested using a test code on a simplemore » problem containing 8 assemblies in a square pool. The standard Monte Carlo method gave the expected eigenfunction in 5 cases out of 10, while the fission matrix method gave the expected eigenfunction in all 10 cases. In addition, the fission matrix method provides an estimate of the error in the eigenvalue and the eigenfunction, and it allows the user to control this error by running an adequate number of cycles. Because of these advantages, the fission matrix method yields a higher confidence in the results than standard Monte Carlo. We also discuss potential improvements of the method, including the potential for variance reduction techniques. (authors)« less

Accuracy of Monte Carlo simulations compared to in-vivo MDCT dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bostani, Maryam, E-mail: mbostani@mednet.ucla.edu; McMillan, Kyle; Cagnon, Chris H.

Purpose: The purpose of this study was to assess the accuracy of a Monte Carlo simulation-based method for estimating radiation dose from multidetector computed tomography (MDCT) by comparing simulated doses in ten patients to in-vivo dose measurements. Methods: MD Anderson Cancer Center Institutional Review Board approved the acquisition of in-vivo rectal dose measurements in a pilot study of ten patients undergoing virtual colonoscopy. The dose measurements were obtained by affixing TLD capsules to the inner lumen of rectal catheters. Voxelized patient models were generated from the MDCT images of the ten patients, and the dose to the TLD for allmore » exposures was estimated using Monte Carlo based simulations. The Monte Carlo simulation results were compared to the in-vivo dose measurements to determine accuracy. Results: The calculated mean percent difference between TLD measurements and Monte Carlo simulations was −4.9% with standard deviation of 8.7% and a range of −22.7% to 5.7%. Conclusions: The results of this study demonstrate very good agreement between simulated and measured doses in-vivo. Taken together with previous validation efforts, this work demonstrates that the Monte Carlo simulation methods can provide accurate estimates of radiation dose in patients undergoing CT examinations.« less

Monte Carlo Methodology Serves Up a Software Success

NASA Technical Reports Server (NTRS)

2003-01-01

Widely used for the modeling of gas flows through the computation of the motion and collisions of representative molecules, the Direct Simulation Monte Carlo method has become the gold standard for producing research and engineering predictions in the field of rarefied gas dynamics. Direct Simulation Monte Carlo was first introduced in the early 1960s by Dr. Graeme Bird, a professor at the University of Sydney, Australia. It has since proved to be a valuable tool to the aerospace and defense industries in providing design and operational support data, as well as flight data analysis. In 2002, NASA brought to the forefront a software product that maintains the same basic physics formulation of Dr. Bird's method, but provides effective modeling of complex, three-dimensional, real vehicle simulations and parallel processing capabilities to handle additional computational requirements, especially in areas where computational fluid dynamics (CFD) is not applicable. NASA's Direct Simulation Monte Carlo Analysis Code (DAC) software package is now considered the Agency s premier high-fidelity simulation tool for predicting vehicle aerodynamics and aerothermodynamic environments in rarified, or low-density, gas flows.

Dynamic Monte Carlo description of thermal desorption processes

NASA Astrophysics Data System (ADS)

Weinketz, Sieghard

1994-07-01

The applicability of the dynamic Monte Carlo method of Fichthorn and Weinberg, in which the time evolution of a system is described in terms of the absolute number of different microscopic possible events and their associated transition rates, is discussed for the case of thermal desorption simulations. It is shown that the definition of the time increment at each successful event leads naturally to the macroscopic differential equation of desorption, in the case of simple first- and second-order processes in which the only possible events are desorption and diffusion. This equivalence is numerically demonstrated for a second-order case. In the sequence, the equivalence of this method with the Monte Carlo method of Sales and Zgrablich for more complex desorption processes, allowing for lateral interactions between adsorbates, is shown, even though the dynamic Monte Carlo method does not bear their limitation of a rapid surface diffusion condition, thus being able to describe a more complex ``kinetics'' of surface reactive processes, and therefore be applied to a wider class of phenomena, such as surface catalysis.

Semi-stochastic full configuration interaction quantum Monte Carlo

NASA Astrophysics Data System (ADS)

Holmes, Adam; Petruzielo, Frank; Khadilkar, Mihir; Changlani, Hitesh; Nightingale, M. P.; Umrigar, C. J.

2012-02-01

In the recently proposed full configuration interaction quantum Monte Carlo (FCIQMC) [1,2], the ground state is projected out stochastically, using a population of walkers each of which represents a basis state in the Hilbert space spanned by Slater determinants. The infamous fermion sign problem manifests itself in the fact that walkers of either sign can be spawned on a given determinant. We propose an improvement on this method in the form of a hybrid stochastic/deterministic technique, which we expect will improve the efficiency of the algorithm by ameliorating the sign problem. We test the method on atoms and molecules, e.g., carbon, carbon dimer, N2 molecule, and stretched N2. [4pt] [1] Fermion Monte Carlo without fixed nodes: a Game of Life, death and annihilation in Slater Determinant space. George Booth, Alex Thom, Ali Alavi. J Chem Phys 131, 050106, (2009).[0pt] [2] Survival of the fittest: Accelerating convergence in full configuration-interaction quantum Monte Carlo. Deidre Cleland, George Booth, and Ali Alavi. J Chem Phys 132, 041103 (2010).

pyNSMC: A Python Module for Null-Space Monte Carlo Uncertainty Analysis

NASA Astrophysics Data System (ADS)

White, J.; Brakefield, L. K.

2015-12-01

The null-space monte carlo technique is a non-linear uncertainty analyses technique that is well-suited to high-dimensional inverse problems. While the technique is powerful, the existing workflow for completing null-space monte carlo is cumbersome, requiring the use of multiple commandline utilities, several sets of intermediate files and even a text editor. pyNSMC is an open-source python module that automates the workflow of null-space monte carlo uncertainty analyses. The module is fully compatible with the PEST and PEST++ software suites and leverages existing functionality of pyEMU, a python framework for linear-based uncertainty analyses. pyNSMC greatly simplifies the existing workflow for null-space monte carlo by taking advantage of object oriented design facilities in python. The core of pyNSMC is the ensemble class, which draws and stores realized random vectors and also provides functionality for exporting and visualizing results. By relieving users of the tedium associated with file handling and command line utility execution, pyNSMC instead focuses the user on the important steps and assumptions of null-space monte carlo analysis. Furthermore, pyNSMC facilitates learning through flow charts and results visualization, which are available at many points in the algorithm. The ease-of-use of the pyNSMC workflow is compared to the existing workflow for null-space monte carlo for a synthetic groundwater model with hundreds of estimable parameters.

Mathematical skills in 3- and 5-year-olds with spina bifida and their typically developing peers: a longitudinal approach.

PubMed

Barnes, Marcia A; Stubbs, Allison; Raghubar, Kimberly P; Agostino, Alba; Taylor, Heather; Landry, Susan; Fletcher, Jack M; Smith-Chant, Brenda

2011-05-01

Preschoolers with spina bifida (SB) were compared to typically developing (TD) children on tasks tapping mathematical knowledge at 36 months (n = 102) and 60 months of age (n = 98). The group with SB had difficulty compared to TD peers on all mathematical tasks except for transformation on quantities in the subitizable range. At 36 months, vocabulary knowledge, visual-spatial, and fine motor abilities predicted achievement on a measure of informal math knowledge in both groups. At 60 months of age, phonological awareness, visual-spatial ability, and fine motor skill were uniquely and differentially related to counting knowledge, oral counting, object-based arithmetic skills, and quantitative concepts. Importantly, the patterns of association between these predictors and mathematical performance were similar across the groups. A novel finding is that fine motor skill uniquely predicted object-based arithmetic abilities in both groups, suggesting developmental continuity in the neurocognitive correlates of early object-based and later symbolic arithmetic problem solving. Models combining 36-month mathematical ability and these language-based, visual-spatial, and fine motor abilities at 60 months accounted for considerable variance on 60-month informal mathematical outcomes. Results are discussed with reference to models of mathematical development and early identification of risk in preschoolers with neurodevelopmental disorder.

Mathematical Skills in 3- and 5-Year-Olds with Spina Bifida and Their Typically Developing Peers: A Longitudinal Approach

PubMed Central

Barnes, Marcia A.; Stubbs, Allison; Raghubar, Kimberly P.; Agostino, Alba; Taylor, Heather; Landry, Susan; Fletcher, Jack M.; Smith-Chant, Brenda

2011-01-01

Preschoolers with spina bifida (SB) were compared to typically developing (TD) children on tasks tapping mathematical knowledge at 36 months (n = 102) and 60 months of age (n = 98). The group with SB had difficulty compared to TD peers on all mathematical tasks except for transformation on quantities in the subitizable range. At 36 months, vocabulary knowledge, visual–spatial, and fine motor abilities predicted achievement on a measure of informal math knowledge in both groups. At 60 months of age, phonological awareness, visual–spatial ability, and fine motor skill were uniquely and differentially related to counting knowledge, oral counting, object-based arithmetic skills, and quantitative concepts. Importantly, the patterns of association between these predictors and mathematical performance were similar across the groups. A novel finding is that fine motor skill uniquely predicted object-based arithmetic abilities in both groups, suggesting developmental continuity in the neurocognitive correlates of early object-based and later symbolic arithmetic problem solving. Models combining 36-month mathematical ability and these language-based, visual–spatial, and fine motor abilities at 60 months accounted for considerable variance on 60-month informal mathematical outcomes. Results are discussed with reference to models of mathematical development and early identification of risk in preschoolers with neurodevelopmental disorder. PMID:21418718

A Monte Carlo Simulation of Brownian Motion in the Freshman Laboratory

ERIC Educational Resources Information Center

Anger, C. D.; Prescott, J. R.

1970-01-01

Describes a dry- lab" experiment for the college freshman laboratory, in which the essential features of Browian motion are given principles, using the Monte Carlo technique. Calculations principles, using the Monte Carlo technique. Calculations are carried out by a computation sheme based on computer language. Bibliography. (LC)

Multiscale Monte Carlo equilibration: Pure Yang-Mills theory

DOE PAGES

Endres, Michael G.; Brower, Richard C.; Orginos, Kostas; ...

2015-12-29

In this study, we present a multiscale thermalization algorithm for lattice gauge theory, which enables efficient parallel generation of uncorrelated gauge field configurations. The algorithm combines standard Monte Carlo techniques with ideas drawn from real space renormalization group and multigrid methods. We demonstrate the viability of the algorithm for pure Yang-Mills gauge theory for both heat bath and hybrid Monte Carlo evolution, and show that it ameliorates the problem of topological freezing up to controllable lattice spacing artifacts.

Improved Monte Carlo Renormalization Group Method

DOE R&D Accomplishments Database

Gupta, R.; Wilson, K. G.; Umrigar, C.

1985-01-01

An extensive program to analyze critical systems using an Improved Monte Carlo Renormalization Group Method (IMCRG) being undertaken at LANL and Cornell is described. Here we first briefly review the method and then list some of the topics being investigated.

Optimised Iteration in Coupled Monte Carlo - Thermal-Hydraulics Calculations

NASA Astrophysics Data System (ADS)

Hoogenboom, J. Eduard; Dufek, Jan

2014-06-01

This paper describes an optimised iteration scheme for the number of neutron histories and the relaxation factor in successive iterations of coupled Monte Carlo and thermal-hydraulic reactor calculations based on the stochastic iteration method. The scheme results in an increasing number of neutron histories for the Monte Carlo calculation in successive iteration steps and a decreasing relaxation factor for the spatial power distribution to be used as input to the thermal-hydraulics calculation. The theoretical basis is discussed in detail and practical consequences of the scheme are shown, among which a nearly linear increase per iteration of the number of cycles in the Monte Carlo calculation. The scheme is demonstrated for a full PWR type fuel assembly. Results are shown for the axial power distribution during several iteration steps. A few alternative iteration method are also tested and it is concluded that the presented iteration method is near optimal.

Youth and young adults with spina bifida: their utilization of physician and hospital services.

PubMed

Young, Nancy L; Anselmo, Lianne A; Burke, Tricia A; McCormick, Anna; Mukherjee, Shubhra

2014-03-01

To describe current patterns of health care utilization of youth and young adults who have spina bifida (SB) and provide evidence to guide the development of health care for this growing population. We conducted a secondary analysis of health services utilization data from the Canadian Institute for Health Information to determine the rates and patterns of health care utilization, because comprehensive health care has been recognized as critical to positive health outcomes. Participants were identified from 6 publicly funded children's treatment centers. Health records from youth (n=164; age range, 13.0-17.9y) and adults (n=120; age range, 23.0-32.9y) with SB contributed to this study. Not applicable. The rates of outpatient physician visits and hospital admissions for the youth and adult groups were calculated. The proportion with a "medical home" was also calculated. The annual rates of outpatient physician visits per 1000 persons were 8031 for youth and 8524 for adults with SB. These rates were approximately 2.9 and 2.2 times higher, respectively, than for their age-matched peers. On average, 12% of youth and 24% of adults with SB had a medical home. The annual rates of hospital admissions per 1000 persons were 329 for youth and 285 for adults with SB. Rates of admissions were 19.4 and 12.4 times higher, respectively, for these groups than for the general population. It appears that persons with SB are accessing health services more often than their age-matched peers, and few have a medical home. We recommend that seamless medical care be provided to all adults with SB, coordinated by a primary care provider, to facilitate comprehensive care. Copyright © 2014 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Reconstruction of Human Monte Carlo Geometry from Segmented Images

NASA Astrophysics Data System (ADS)

Zhao, Kai; Cheng, Mengyun; Fan, Yanchang; Wang, Wen; Long, Pengcheng; Wu, Yican

2014-06-01

Human computational phantoms have been used extensively for scientific experimental analysis and experimental simulation. This article presented a method for human geometry reconstruction from a series of segmented images of a Chinese visible human dataset. The phantom geometry could actually describe detailed structure of an organ and could be converted into the input file of the Monte Carlo codes for dose calculation. A whole-body computational phantom of Chinese adult female has been established by FDS Team which is named Rad-HUMAN with about 28.8 billion voxel number. For being processed conveniently, different organs on images were segmented with different RGB colors and the voxels were assigned with positions of the dataset. For refinement, the positions were first sampled. Secondly, the large sums of voxels inside the organ were three-dimensional adjacent, however, there were not thoroughly mergence methods to reduce the cell amounts for the description of the organ. In this study, the voxels on the organ surface were taken into consideration of the mergence which could produce fewer cells for the organs. At the same time, an indexed based sorting algorithm was put forward for enhancing the mergence speed. Finally, the Rad-HUMAN which included a total of 46 organs and tissues was described by the cuboids into the Monte Carlo Monte Carlo Geometry for the simulation. The Monte Carlo geometry was constructed directly from the segmented images and the voxels was merged exhaustively. Each organ geometry model was constructed without ambiguity and self-crossing, its geometry information could represent the accuracy appearance and precise interior structure of the organs. The constructed geometry largely retaining the original shape of organs could easily be described into different Monte Carlo codes input file such as MCNP. Its universal property was testified and high-performance was experimentally verified

Accelerated Monte Carlo Simulation for Safety Analysis of the Advanced Airspace Concept

NASA Technical Reports Server (NTRS)

Thipphavong, David

2010-01-01

Safe separation of aircraft is a primary objective of any air traffic control system. An accelerated Monte Carlo approach was developed to assess the level of safety provided by a proposed next-generation air traffic control system. It combines features of fault tree and standard Monte Carlo methods. It runs more than one order of magnitude faster than the standard Monte Carlo method while providing risk estimates that only differ by about 10%. It also preserves component-level model fidelity that is difficult to maintain using the standard fault tree method. This balance of speed and fidelity allows sensitivity analysis to be completed in days instead of weeks or months with the standard Monte Carlo method. Results indicate that risk estimates are sensitive to transponder, pilot visual avoidance, and conflict detection failure probabilities.

Path integral Monte Carlo and the electron gas

NASA Astrophysics Data System (ADS)

Brown, Ethan W.

Path integral Monte Carlo is a proven method for accurately simulating quantum mechanical systems at finite-temperature. By stochastically sampling Feynman's path integral representation of the quantum many-body density matrix, path integral Monte Carlo includes non-perturbative effects like thermal fluctuations and particle correlations in a natural way. Over the past 30 years, path integral Monte Carlo has been successfully employed to study the low density electron gas, high-pressure hydrogen, and superfluid helium. For systems where the role of Fermi statistics is important, however, traditional path integral Monte Carlo simulations have an exponentially decreasing efficiency with decreased temperature and increased system size. In this thesis, we work towards improving this efficiency, both through approximate and exact methods, as specifically applied to the homogeneous electron gas. We begin with a brief overview of the current state of atomic simulations at finite-temperature before we delve into a pedagogical review of the path integral Monte Carlo method. We then spend some time discussing the one major issue preventing exact simulation of Fermi systems, the sign problem. Afterwards, we introduce a way to circumvent the sign problem in PIMC simulations through a fixed-node constraint. We then apply this method to the homogeneous electron gas at a large swatch of densities and temperatures in order to map out the warm-dense matter regime. The electron gas can be a representative model for a host of real systems, from simple medals to stellar interiors. However, its most common use is as input into density functional theory. To this end, we aim to build an accurate representation of the electron gas from the ground state to the classical limit and examine its use in finite-temperature density functional formulations. The latter half of this thesis focuses on possible routes beyond the fixed-node approximation. As a first step, we utilize the variational

Monte Carlo methods for multidimensional integration for European option pricing

NASA Astrophysics Data System (ADS)

Todorov, V.; Dimov, I. T.

2016-10-01

In this paper, we illustrate examples of highly accurate Monte Carlo and quasi-Monte Carlo methods for multiple integrals related to the evaluation of European style options. The idea is that the value of the option is formulated in terms of the expectation of some random variable; then the average of independent samples of this random variable is used to estimate the value of the option. First we obtain an integral representation for the value of the option using the risk neutral valuation formula. Then with an appropriations change of the constants we obtain a multidimensional integral over the unit hypercube of the corresponding dimensionality. Then we compare a specific type of lattice rules over one of the best low discrepancy sequence of Sobol for numerical integration. Quasi-Monte Carlo methods are compared with Adaptive and Crude Monte Carlo techniques for solving the problem. The four approaches are completely different thus it is a question of interest to know which one of them outperforms the other for evaluation multidimensional integrals in finance. Some of the advantages and disadvantages of the developed algorithms are discussed.

Harnessing graphical structure in Markov chain Monte Carlo learning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stolorz, P.E.; Chew P.C.

1996-12-31

The Monte Carlo method is recognized as a useful tool in learning and probabilistic inference methods common to many datamining problems. Generalized Hidden Markov Models and Bayes nets are especially popular applications. However, the presence of multiple modes in many relevant integrands and summands often renders the method slow and cumbersome. Recent mean field alternatives designed to speed things up have been inspired by experience gleaned from physics. The current work adopts an approach very similar to this in spirit, but focusses instead upon dynamic programming notions as a basis for producing systematic Monte Carlo improvements. The idea is tomore » approximate a given model by a dynamic programming-style decomposition, which then forms a scaffold upon which to build successively more accurate Monte Carlo approximations. Dynamic programming ideas alone fail to account for non-local structure, while standard Monte Carlo methods essentially ignore all structure. However, suitably-crafted hybrids can successfully exploit the strengths of each method, resulting in algorithms that combine speed with accuracy. The approach relies on the presence of significant {open_quotes}local{close_quotes} information in the problem at hand. This turns out to be a plausible assumption for many important applications. Example calculations are presented, and the overall strengths and weaknesses of the approach are discussed.« less

Work participation among middle-aged persons with cerebral palsy or spina bifida--a longitudinal study.

PubMed

Törnbom, Marie; Jonsson, Ulrica; Sunnerhagen, Katharina S

2014-04-01

Most studies of work participation among persons with cerebral palsy (CP) or spina bifida (SB) have focused on young adults, little is known about older adults. The aim of this study was to compare work participation in 2009 with 1997 (98). Two groups of persons with CP or SB in Gothenburg, Sweden with an IQ above 70 were interviewed using a structured questionnaire regarding work participation. Group (A) was studied in 1983 (n = 55), in 1997 (n = 42) and in 2009 (n = 28). Group (B) was studied in 1998 (n = 30) and in 2009 (n = 25). In this study, the persons interviewed in 2009 were compared with their own data from 1997 (8), with a non-parametric test. Work participation had significantly decreased (p < 0.004) since 1997 (8); more persons worked part time or had stopped working. Thirty-eight percent had continued their education during 1997 (8)-2009, most of them worked. Of 34 persons working in 2009, 56% had wage subsidies, an increase from 42% in 1997 (8). Of the persons who worked and had continued their education, 37.5% had wage subsidies while, among persons without continued education, 72% had this support. Transportation to work functioned but not as well as in 1997 (8). More persons used transportation for people with a disability in 2009 than in 1997 (8) and criticism was expressed about the transportation system. Results showed that work participation for middle-aged persons with CP or SB without intellectual disability decreased with age but continued education and wage subsidies facilitated work participation. Copyright © 2014 Elsevier Inc. All rights reserved.

Emotional health and coping in spina bifida after goal management training: a randomized controlled trial.

PubMed

Stubberud, Jan; Langenbahn, Donna; Levine, Brian; Stanghelle, Johan; Schanke, Anne-Kristine

2015-02-01

Executive function impairments are common after spina bifida (SB) and potentially have a detrimental effect on the individual's emotional health and coping. Goal management training (GMT) is a cognitive rehabilitation method for improving executive function. The purpose of this study was to determine the efficacy of GMT on aspects of perceived emotional health and coping in individuals with SB. Thirty-eight adult subjects with SB were included in this randomized controlled trial. Inclusion was based upon the presence of executive functioning complaints. Experimental subjects (n = 24) received 21 hr of GMT, with efficacy of GMT being compared with results of subjects in a wait-list condition (n = 14). Four self-report questionnaires assessing emotional health and coping were utilized as outcome measures. All subjects were assessed at baseline, postintervention, and at 6-month follow-up. Findings indicated positive effects of GMT relative to the control group on measures of emotional health. Of note, the GMT group showed significant improvement, compared with control subjects, on a self-report inventory of depressive and anxiety symptoms after training, lasting at least 6 months posttreatment. Furthermore, both groups showed improvements after training on mental health components of health-related quality of life. Finally, the GMT group showed a significant increase in task-focused coping and a decrease in avoidant coping after training compared with pretreatment baseline assessment scores. Overall, findings indicate that by us a compensatory intervention to manage executive dysfunction, effective and lasting benefits can be achieved with regard to aspects of perceived emotional health and coping. PsycINFO Database Record (c) 2015 APA, all rights reserved.

PEPSI — a Monte Carlo generator for polarized leptoproduction

NASA Astrophysics Data System (ADS)

Mankiewicz, L.; Schäfer, A.; Veltri, M.

1992-09-01

We describe PEPSI (Polarized Electron Proton Scattering Interactions), a Monte Carlo program for polarized deep inelastic leptoproduction mediated by electromagnetic interaction, and explain how to use it. The code is a modification of the LEPTO 4.3 Lund Monte Carlo for unpolarized scattering. The hard virtual gamma-parton scattering is generated according to the polarization-dependent QCD cross-section of the first order in α S. PEPSI requires the standard polarization-independent JETSET routines to simulate the fragmentation into final hadrons.

Hypothesis testing of scientific Monte Carlo calculations.

PubMed

Wallerberger, Markus; Gull, Emanuel

2017-11-01

The steadily increasing size of scientific Monte Carlo simulations and the desire for robust, correct, and reproducible results necessitates rigorous testing procedures for scientific simulations in order to detect numerical problems and programming bugs. However, the testing paradigms developed for deterministic algorithms have proven to be ill suited for stochastic algorithms. In this paper we demonstrate explicitly how the technique of statistical hypothesis testing, which is in wide use in other fields of science, can be used to devise automatic and reliable tests for Monte Carlo methods, and we show that these tests are able to detect some of the common problems encountered in stochastic scientific simulations. We argue that hypothesis testing should become part of the standard testing toolkit for scientific simulations.

Hypothesis testing of scientific Monte Carlo calculations

NASA Astrophysics Data System (ADS)

Wallerberger, Markus; Gull, Emanuel

2017-11-01

The steadily increasing size of scientific Monte Carlo simulations and the desire for robust, correct, and reproducible results necessitates rigorous testing procedures for scientific simulations in order to detect numerical problems and programming bugs. However, the testing paradigms developed for deterministic algorithms have proven to be ill suited for stochastic algorithms. In this paper we demonstrate explicitly how the technique of statistical hypothesis testing, which is in wide use in other fields of science, can be used to devise automatic and reliable tests for Monte Carlo methods, and we show that these tests are able to detect some of the common problems encountered in stochastic scientific simulations. We argue that hypothesis testing should become part of the standard testing toolkit for scientific simulations.

Mission Analysis, Operations, and Navigation Toolkit Environment (Monte) Version 040

NASA Technical Reports Server (NTRS)

Sunseri, Richard F.; Wu, Hsi-Cheng; Evans, Scott E.; Evans, James R.; Drain, Theodore R.; Guevara, Michelle M.

2012-01-01

Monte is a software set designed for use in mission design and spacecraft navigation operations. The system can process measurement data, design optimal trajectories and maneuvers, and do orbit determination, all in one application. For the first time, a single software set can be used for mission design and navigation operations. This eliminates problems due to different models and fidelities used in legacy mission design and navigation software. The unique features of Monte 040 include a blowdown thruster model for GRAIL (Gravity Recovery and Interior Laboratory) with associated pressure models, as well as an updated, optimalsearch capability (COSMIC) that facilitated mission design for ARTEMIS. Existing legacy software lacked the capabilities necessary for these two missions. There is also a mean orbital element propagator and an osculating to mean element converter that allows long-term orbital stability analysis for the first time in compiled code. The optimized trajectory search tool COSMIC allows users to place constraints and controls on their searches without any restrictions. Constraints may be user-defined and depend on trajectory information either forward or backwards in time. In addition, a long-term orbit stability analysis tool (morbiter) existed previously as a set of scripts on top of Monte. Monte is becoming the primary tool for navigation operations, a core competency at JPL. The mission design capabilities in Monte are becoming mature enough for use in project proposals as well as post-phase A mission design. Monte has three distinct advantages over existing software. First, it is being developed in a modern paradigm: object- oriented C++ and Python. Second, the software has been developed as a toolkit, which allows users to customize their own applications and allows the development team to implement requirements quickly, efficiently, and with minimal bugs. Finally, the software is managed in accordance with the CMMI (Capability Maturity Model

PRELIMINARY COUPLING OF THE MONTE CARLO CODE OPENMC AND THE MULTIPHYSICS OBJECT-ORIENTED SIMULATION ENVIRONMENT (MOOSE) FOR ANALYZING DOPPLER FEEDBACK IN MONTE CARLO SIMULATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matthew Ellis; Derek Gaston; Benoit Forget

In recent years the use of Monte Carlo methods for modeling reactors has become feasible due to the increasing availability of massively parallel computer systems. One of the primary challenges yet to be fully resolved, however, is the efficient and accurate inclusion of multiphysics feedback in Monte Carlo simulations. The research in this paper presents a preliminary coupling of the open source Monte Carlo code OpenMC with the open source Multiphysics Object-Oriented Simulation Environment (MOOSE). The coupling of OpenMC and MOOSE will be used to investigate efficient and accurate numerical methods needed to include multiphysics feedback in Monte Carlo codes.more » An investigation into the sensitivity of Doppler feedback to fuel temperature approximations using a two dimensional 17x17 PWR fuel assembly is presented in this paper. The results show a functioning multiphysics coupling between OpenMC and MOOSE. The coupling utilizes Functional Expansion Tallies to accurately and efficiently transfer pin power distributions tallied in OpenMC to unstructured finite element meshes used in MOOSE. The two dimensional PWR fuel assembly case also demonstrates that for a simplified model the pin-by-pin doppler feedback can be adequately replicated by scaling a representative pin based on pin relative powers.« less

Agreement between electronic medical records and self-reported urologic domains in the National Spina Bifida Patient Registry (NSBPR): Implications for future research.

PubMed

Halline, Christopher G; Meyer, Theresa; Rosoklija, Ilina; Yerkes, Elizabeth B

2017-08-01

Self-report (SR) is an efficient data collection method. However, SR data have been shown to be discrepant with medical record (MR) documentation, which raises questions about using SR to supplement retrospective chart review in research. In this study, pediatric spina bifida (SB) patients who completed SR interviews about continence status and personal bladder/bowel management were identified. We examined agreement between SR data and Urology provider notes in MRs. This study aimed to (1) identify demographic, medical, or methodological factors that might contribute to SR/MR disagreement; (2) postulate how these findings might be significant clinically; and (3) recommend improvements to SR data collection and MR documentation. Our institution participates in the National Spina Bifida Patient Registry (NSBPR). NSBPR-enrolled subjects typically complete annual interviews about their urologic outcomes; we consider this to be a form of SR. After identifying patients who interviewed within 1 month of an encounter with a urology provider, we systematically reviewed and compared their SR responses to the MR. Overall SR/MR agreement (no. of agreeing data pairs/no. of complete data pairs) and strength of agreement (kappa, κ) were assessed. Agreement about daytime continence status was assessed for children ≥5 years or in younger children who were toilet trained. Analyses were also stratified by diagnosis, type of bladder management, and ethnicity. Eleven urologic domains were analyzed for 176 patients. Overall SR/MR agreement was ≥90% for nine out of 11 domains (figure). Daytime urinary and stool incontinence (DUSI) domains demonstrated the lowest overall agreement, at 69% and 74% respectively. Patients with myelomeningocele (MM) and those on clean intermittent catheterization demonstrated twice as much SR/MR disagreement about DUSI than patients without MM and those who void. There was no significant difference in rates of SR/MR agreement about DUSI when analyzed by

COMPARISON OF MONTE CARLO METHODS FOR NONLINEAR RADIATION TRANSPORT

DOE Office of Scientific and Technical Information (OSTI.GOV)

W. R. MARTIN; F. B. BROWN

2001-03-01

Five Monte Carlo methods for solving the nonlinear thermal radiation transport equations are compared. The methods include the well-known Implicit Monte Carlo method (IMC) developed by Fleck and Cummings, an alternative to IMC developed by Carter and Forest, an ''exact'' method recently developed by Ahrens and Larsen, and two methods recently proposed by Martin and Brown. The five Monte Carlo methods are developed and applied to the radiation transport equation in a medium assuming local thermodynamic equilibrium. Conservation of energy is derived and used to define appropriate material energy update equations for each of the methods. Details of the Montemore » Carlo implementation are presented, both for the random walk simulation and the material energy update. Simulation results for all five methods are obtained for two infinite medium test problems and a 1-D test problem, all of which have analytical solutions. Conclusions regarding the relative merits of the various schemes are presented.« less

Ground state of excitonic molecules by the Green's-function Monte Carlo method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, M.A.; Vashishta, P.; Kalia, R.K.

1983-12-26

The ground-state energy of excitonic molecules is evaluated as a function of the ratio of electron and hole masses, sigma, with use of the Green's-function Monte Carlo method. For all sigma, the Green's-function Monte Carlo energies are significantly lower than the variational estimates and in favorable agreement with experiments. In excitonic rydbergs, the binding energy of the positronium molecule (sigma = 1) is predicted to be -0.06 and for sigma<<1, the Green's-function Monte Carlo energies agree with the ''exact'' limiting behavior, E = -2.346+0.764sigma.

Structural Reliability and Monte Carlo Simulation.

ERIC Educational Resources Information Center

Laumakis, P. J.; Harlow, G.

2002-01-01

Analyzes a simple boom structure and assesses its reliability using elementary engineering mechanics. Demonstrates the power and utility of Monte-Carlo simulation by showing that such a simulation can be implemented more readily with results that compare favorably to the theoretical calculations. (Author/MM)

Physical time scale in kinetic Monte Carlo simulations of continuous-time Markov chains.

PubMed

Serebrinsky, Santiago A

2011-03-01

We rigorously establish a physical time scale for a general class of kinetic Monte Carlo algorithms for the simulation of continuous-time Markov chains. This class of algorithms encompasses rejection-free (or BKL) and rejection (or "standard") algorithms. For rejection algorithms, it was formerly considered that the availability of a physical time scale (instead of Monte Carlo steps) was empirical, at best. Use of Monte Carlo steps as a time unit now becomes completely unnecessary.

Risk factors for latex allergy in patients with spina bifida and latex sensitization.

PubMed

Bernardini, R; Novembre, E; Lombardi, E; Mezzetti, P; Cianferoni, A; Danti, D A; Mercurella, A; Vierucci, A

1999-05-01

Some subjects with spina bifida (SB) and latex sensitization (cutaneous and/or serum IgE) can have clinical reactions, while others may have no symptoms after the exposure to latex products. This study was carried out to determine the risk factors associated with latex allergy in patients affected with SB and latex sensitization. Fifty-nine consecutive subjects affected with SB, besides answering a questionnaire, underwent a skin-prick test (SPT) to latex and the determination of the specific serum IgE (RAST CAP) to latex. The total serum IgE concentration was determined and SPT to common aero- and food-allergens, skin tests (prick + prick) with fresh foods (kiwi, pear, orange, pineapple, tomato, banana) and RAST CAP to the same foods tested by the prick + prick technique, were also performed. Fifteen out of the 59 subjects (25%) were sensitized to latex according to the presence of IgE to latex detected by SPT (nine patients) and/or RAST CAP (13 patients). Five out of the 15 sensitized patients (33%) suffered from clinical reactions to latex (urticaria, conjunctivitis, angioedema, rhinitis, bronchial asthma) while they were using latex gloves and while inflating latex balloons. In the 15 sensitized patients, the presence of specific latex seric IgE > 3.5 kU/L (>/= class 3), a positive latex SPT, an elevated total serum IgE, and a positive prick + prick and/or a positive RAST CAP to foods, were significant (P < 0.05) risk factors associated with latex symptoms. The other factors tested (age, gender, months of intermittent bladder catheterization, surgical procedures, SPT reactivity and clinical reactions to aero-allergens and food-allergens, skin tests for fresh foods, positive RAST CAP to foods) were not significantly different in symptomatic and asymptomatic patients. Significant risk factors for symptoms to latex in patients with SB and latex sensitization were a presence of specific IgE to latex > 3.5 kU/L, a more frequent positive latex SPT, elevated total Ig

Correlated uncertainties in Monte Carlo reaction rate calculations

NASA Astrophysics Data System (ADS)

Longland, Richard

2017-07-01

Context. Monte Carlo methods have enabled nuclear reaction rates from uncertain inputs to be presented in a statistically meaningful manner. However, these uncertainties are currently computed assuming no correlations between the physical quantities that enter those calculations. This is not always an appropriate assumption. Astrophysically important reactions are often dominated by resonances, whose properties are normalized to a well-known reference resonance. This insight provides a basis from which to develop a flexible framework for including correlations in Monte Carlo reaction rate calculations. Aims: The aim of this work is to develop and test a method for including correlations in Monte Carlo reaction rate calculations when the input has been normalized to a common reference. Methods: A mathematical framework is developed for including correlations between input parameters in Monte Carlo reaction rate calculations. The magnitude of those correlations is calculated from the uncertainties typically reported in experimental papers, where full correlation information is not available. The method is applied to four illustrative examples: a fictional 3-resonance reaction, 27Al(p, γ)28Si, 23Na(p, α)20Ne, and 23Na(α, p)26Mg. Results: Reaction rates at low temperatures that are dominated by a few isolated resonances are found to minimally impacted by correlation effects. However, reaction rates determined from many overlapping resonances can be significantly affected. Uncertainties in the 23Na(α, p)26Mg reaction, for example, increase by up to a factor of 5. This highlights the need to take correlation effects into account in reaction rate calculations, and provides insight into which cases are expected to be most affected by them. The impact of correlation effects on nucleosynthesis is also investigated.

A Monte Carlo simulation study of associated liquid crystals

NASA Astrophysics Data System (ADS)

Berardi, R.; Fehervari, M.; Zannoni, C.

We have performed a Monte Carlo simulation study of a system of ellipsoidal particles with donor-acceptor sites modelling complementary hydrogen-bonding groups in real molecules. We have considered elongated Gay-Berne particles with terminal interaction sites allowing particles to associate and form dimers. The changes in the phase transitions and in the molecular organization and the interplay between orientational ordering and dimer formation are discussed. Particle flip and dimer moves have been used to increase the convergency rate of the Monte Carlo (MC) Markov chain.

Efficient Monte Carlo Methods for Biomolecular Simulations.

NASA Astrophysics Data System (ADS)

Bouzida, Djamal

A new approach to efficient Monte Carlo simulations of biological molecules is presented. By relaxing the usual restriction to Markov processes, we are able to optimize performance while dealing directly with the inhomogeneity and anisotropy inherent in these systems. The advantage of this approach is that we can introduce a wide variety of Monte Carlo moves to deal with complicated motions of the molecule, while maintaining full optimization at every step. This enables the use of a variety of collective rotational moves that relax long-wavelength modes. We were able to show by explicit simulations that the resulting algorithms substantially increase the speed of the simulation while reproducing the correct equilibrium behavior. This approach is particularly intended for simulations of macromolecules, although we expect it to be useful in other situations. The dynamic optimization of the new Monte Carlo methods makes them very suitable for simulated annealing experiments on all systems whose state space is continuous in general, and to the protein folding problem in particular. We introduce an efficient annealing schedule using preferential bias moves. Our simulated annealing experiments yield structures whose free energies were lower than the equilibrated X-ray structure, which leads us to believe that the empirical energy function used does not fully represent the interatomic interactions. Furthermore, we believe that the largest discrepancies involve the solvent effects in particular.

Analytic continuation of quantum Monte Carlo data by stochastic analytical inference.

PubMed

Fuchs, Sebastian; Pruschke, Thomas; Jarrell, Mark

2010-05-01

We present an algorithm for the analytic continuation of imaginary-time quantum Monte Carlo data which is strictly based on principles of Bayesian statistical inference. Within this framework we are able to obtain an explicit expression for the calculation of a weighted average over possible energy spectra, which can be evaluated by standard Monte Carlo simulations, yielding as by-product also the distribution function as function of the regularization parameter. Our algorithm thus avoids the usual ad hoc assumptions introduced in similar algorithms to fix the regularization parameter. We apply the algorithm to imaginary-time quantum Monte Carlo data and compare the resulting energy spectra with those from a standard maximum-entropy calculation.

Monte Carlo Simulation of THz Multipliers

NASA Technical Reports Server (NTRS)

East, J.; Blakey, P.

1997-01-01

Schottky Barrier diode frequency multipliers are critical components in submillimeter and Thz space based earth observation systems. As the operating frequency of these multipliers has increased, the agreement between design predictions and experimental results has become poorer. The multiplier design is usually based on a nonlinear model using a form of harmonic balance and a model for the Schottky barrier diode. Conventional voltage dependent lumped element models do a poor job of predicting THz frequency performance. This paper will describe a large signal Monte Carlo simulation of Schottky barrier multipliers. The simulation is a time dependent particle field Monte Carlo simulation with ohmic and Schottky barrier boundary conditions included that has been combined with a fixed point solution for the nonlinear circuit interaction. The results in the paper will point out some important time constants in varactor operation and will describe the effects of current saturation and nonlinear resistances on multiplier operation.

Exact Dynamics via Poisson Process: a unifying Monte Carlo paradigm

NASA Astrophysics Data System (ADS)

Gubernatis, James

2014-03-01

A common computational task is solving a set of ordinary differential equations (o.d.e.'s). A little known theorem says that the solution of any set of o.d.e.'s is exactly solved by the expectation value over a set of arbitary Poisson processes of a particular function of the elements of the matrix that defines the o.d.e.'s. The theorem thus provides a new starting point to develop real and imaginary-time continous-time solvers for quantum Monte Carlo algorithms, and several simple observations enable various quantum Monte Carlo techniques and variance reduction methods to transfer to a new context. I will state the theorem, note a transformation to a very simple computational scheme, and illustrate the use of some techniques from the directed-loop algorithm in context of the wavefunction Monte Carlo method that is used to solve the Lindblad master equation for the dynamics of open quantum systems. I will end by noting that as the theorem does not depend on the source of the o.d.e.'s coming from quantum mechanics, it also enables the transfer of continuous-time methods from quantum Monte Carlo to the simulation of various classical equations of motion heretofore only solved deterministically.

Monte Carlo simulation of proton track structure in biological matter

DOE PAGES

Quinto, Michele A.; Monti, Juan M.; Weck, Philippe F.; ...

2017-05-25

Here, understanding the radiation-induced effects at the cellular and subcellular levels remains crucial for predicting the evolution of irradiated biological matter. In this context, Monte Carlo track-structure simulations have rapidly emerged among the most suitable and powerful tools. However, most existing Monte Carlo track-structure codes rely heavily on the use of semi-empirical cross sections as well as water as a surrogate for biological matter. In the current work, we report on the up-to-date version of our homemade Monte Carlo code TILDA-V – devoted to the modeling of the slowing-down of 10 keV–100 MeV protons in both water and DNA –more » where the main collisional processes are described by means of an extensive set of ab initio differential and total cross sections.« less

Monte Carlo-based Reconstruction in Water Cherenkov Detectors using Chroma

NASA Astrophysics Data System (ADS)

Seibert, Stanley; Latorre, Anthony

2012-03-01

We demonstrate the feasibility of event reconstruction---including position, direction, energy and particle identification---in water Cherenkov detectors with a purely Monte Carlo-based method. Using a fast optical Monte Carlo package we have written, called Chroma, in combination with several variance reduction techniques, we can estimate the value of a likelihood function for an arbitrary event hypothesis. The likelihood can then be maximized over the parameter space of interest using a form of gradient descent designed for stochastic functions. Although slower than more traditional reconstruction algorithms, this completely Monte Carlo-based technique is universal and can be applied to a detector of any size or shape, which is a major advantage during the design phase of an experiment. As a specific example, we focus on reconstruction results from a simulation of the 200 kiloton water Cherenkov far detector option for LBNE.

Monte Carlo simulation of proton track structure in biological matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quinto, Michele A.; Monti, Juan M.; Weck, Philippe F.

Here, understanding the radiation-induced effects at the cellular and subcellular levels remains crucial for predicting the evolution of irradiated biological matter. In this context, Monte Carlo track-structure simulations have rapidly emerged among the most suitable and powerful tools. However, most existing Monte Carlo track-structure codes rely heavily on the use of semi-empirical cross sections as well as water as a surrogate for biological matter. In the current work, we report on the up-to-date version of our homemade Monte Carlo code TILDA-V – devoted to the modeling of the slowing-down of 10 keV–100 MeV protons in both water and DNA –more » where the main collisional processes are described by means of an extensive set of ab initio differential and total cross sections.« less

Ex Post Facto Monte Carlo Variance Reduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Booth, Thomas E.

The variance in Monte Carlo particle transport calculations is often dominated by a few particles whose importance increases manyfold on a single transport step. This paper describes a novel variance reduction method that uses a large importance change as a trigger to resample the offending transport step. That is, the method is employed only after (ex post facto) a random walk attempts a transport step that would otherwise introduce a large variance in the calculation.Improvements in two Monte Carlo transport calculations are demonstrated empirically using an ex post facto method. First, the method is shown to reduce the variance inmore » a penetration problem with a cross-section window. Second, the method empirically appears to modify a point detector estimator from an infinite variance estimator to a finite variance estimator.« less

Intracranial translucency as a sonographic marker for detecting open spina bifida at 11–13+6 weeks scan: Our experience

PubMed Central

Teegala, Madhavi L; Vinayak, Dhamangaonkar G

2017-01-01

Aims and Objectives: The fourth ventricle, seen as intracranial translucency (IT) at 11–13+6 weeks, has been reported to be obliterated in cases of open spina bifida (OSB). Our aim was to assess its role in detecting OSB at 11–13+6 weeks. Materials and Methods: This prospective study was conducted at foetal medicine unit from January 2014 to June 2015. All women who underwent both first and mid-trimester scan in our unit were included in the study. IT was categorized as normal, obliterated or not clear. Spine was examined during both scans. Results: Totally, 341 cases were included in the study. IT was found to be obliterated in four cases and not clear in one case. There was demonstrable OSB at 11–13+6 weeks in two cases, at 15–16 weeks in two cases and at 24 weeks in one case. In the remaining 336 cases with normal IT, spine was found to be normal at target scan. Conclusion: Mid-sagittal view of face that is routinely used to measure nuchal translucency (NT) can also be used to detect OSB. It is feasible to integrate IT into the routine 11–13+6 weeks scan. PMID:29379237

Goal Management Training improves everyday executive functioning for persons with spina bifida: self-and informant reports six months post-training.

PubMed

Stubberud, Jan; Langenbahn, Donna; Levine, Brian; Stanghelle, Johan; Schanke, Anne-Kristine

2014-01-01

Executive dysfunction accounts for significant disability for many patients with spina bifida (SB), thus indicating the need for effective interventions aimed at improving executive functioning in this population. Goal Management Training™ (GMT) is a cognitive rehabilitation approach that targets disorganised behaviour resulting from executive dysfunction, and has received empirical support in studies of other patient groups. The purpose of this study was to determine if GMT would lead to perceived improved executive functioning in the daily lives of patients with SB, as evidenced by reduced report of dysexecutive problems in daily life on self- and informant questionnaires. Thirty-eight adults with SB were included in this randomised controlled trial (RCT). Inclusion was based upon the presence of executive functioning complaints. Experimental subjects (n = 24) received 21 hours of GMT, with efficacy of GMT being compared to results of subjects in a wait-list condition (n = 14). All subjects were assessed at baseline, post-intervention, and at six-month follow-up. Self-report measures indicated that the GMT group's everyday executive functioning improved significantly after training, lasting at least 6 months post-treatment. There were no significant effects on informant-report questionnaires. Overall, these findings indicate that executive difficulties in everyday life can be ameliorated for individuals with congenital brain dysfunction.

78 FR 14031 - Proposed Amendment of Class D Airspace; El Monte, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-04

...: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM). SUMMARY: This action proposes to amend Class D Airspace at El Monte Airport, El Monte, CA. This action, initiated by... particularly helpful in developing reasoned regulatory decisions on the proposal. Comments are specifically...

Study of the Transition Flow Regime using Monte Carlo Methods

NASA Technical Reports Server (NTRS)

Hassan, H. A.

1999-01-01

This NASA Cooperative Agreement presents a study of the Transition Flow Regime Using Monte Carlo Methods. The topics included in this final report are: 1) New Direct Simulation Monte Carlo (DSMC) procedures; 2) The DS3W and DS2A Programs; 3) Papers presented; 4) Miscellaneous Applications and Program Modifications; 5) Solution of Transitional Wake Flows at Mach 10; and 6) Turbulence Modeling of Shock-Dominated Fows with a k-Enstrophy Formulation.

Monte Carlo charged-particle tracking and energy deposition on a Lagrangian mesh.

PubMed

Yuan, J; Moses, G A; McKenty, P W

2005-10-01

A Monte Carlo algorithm for alpha particle tracking and energy deposition on a cylindrical computational mesh in a Lagrangian hydrodynamics code used for inertial confinement fusion (ICF) simulations is presented. The straight line approximation is used to follow propagation of "Monte Carlo particles" which represent collections of alpha particles generated from thermonuclear deuterium-tritium (DT) reactions. Energy deposition in the plasma is modeled by the continuous slowing down approximation. The scheme addresses various aspects arising in the coupling of Monte Carlo tracking with Lagrangian hydrodynamics; such as non-orthogonal severely distorted mesh cells, particle relocation on the moving mesh and particle relocation after rezoning. A comparison with the flux-limited multi-group diffusion transport method is presented for a polar direct drive target design for the National Ignition Facility. Simulations show the Monte Carlo transport method predicts about earlier ignition than predicted by the diffusion method, and generates higher hot spot temperature. Nearly linear speed-up is achieved for multi-processor parallel simulations.

Collision of Physics and Software in the Monte Carlo Application Toolkit (MCATK)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sweezy, Jeremy Ed

2016-01-21

The topic is presented in a series of slides organized as follows: MCATK overview, development strategy, available algorithms, problem modeling (sources, geometry, data, tallies), parallelism, miscellaneous tools/features, example MCATK application, recent areas of research, and summary and future work. MCATK is a C++ component-based Monte Carlo neutron-gamma transport software library with continuous energy neutron and photon transport. Designed to build specialized applications and to provide new functionality in existing general-purpose Monte Carlo codes like MCNP, it reads ACE formatted nuclear data generated by NJOY. The motivation behind MCATK was to reduce costs. MCATK physics involves continuous energy neutron & gammamore » transport with multi-temperature treatment, static eigenvalue (k eff and α) algorithms, time-dependent algorithm, and fission chain algorithms. MCATK geometry includes mesh geometries and solid body geometries. MCATK provides verified, unit-test Monte Carlo components, flexibility in Monte Carlo application development, and numerous tools such as geometry and cross section plotters.« less

Teaching Ionic Solvation Structure with a Monte Carlo Liquid Simulation Program

ERIC Educational Resources Information Center

Serrano, Agostinho; Santos, Flavia M. T.; Greca, Ileana M.

2004-01-01

The use of molecular dynamics and Monte Carlo methods has provided efficient means to stimulate the behavior of molecular liquids and solutions. A Monte Carlo simulation program is used to compute the structure of liquid water and of water as a solvent to Na(super +), Cl(super -), and Ar on a personal computer to show that it is easily feasible to…

Calculation of radiation therapy dose using all particle Monte Carlo transport

DOEpatents

Chandler, William P.; Hartmann-Siantar, Christine L.; Rathkopf, James A.

1999-01-01

The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media.

Calculation of radiation therapy dose using all particle Monte Carlo transport

DOEpatents

Chandler, W.P.; Hartmann-Siantar, C.L.; Rathkopf, J.A.

1999-02-09

The actual radiation dose absorbed in the body is calculated using three-dimensional Monte Carlo transport. Neutrons, protons, deuterons, tritons, helium-3, alpha particles, photons, electrons, and positrons are transported in a completely coupled manner, using this Monte Carlo All-Particle Method (MCAPM). The major elements of the invention include: computer hardware, user description of the patient, description of the radiation source, physical databases, Monte Carlo transport, and output of dose distributions. This facilitated the estimation of dose distributions on a Cartesian grid for neutrons, photons, electrons, positrons, and heavy charged-particles incident on any biological target, with resolutions ranging from microns to centimeters. Calculations can be extended to estimate dose distributions on general-geometry (non-Cartesian) grids for biological and/or non-biological media. 57 figs.

Applying Quantum Monte Carlo to the Electronic Structure Problem

NASA Astrophysics Data System (ADS)

Powell, Andrew D.; Dawes, Richard

2016-06-01

Two distinct types of Quantum Monte Carlo (QMC) calculations are applied to electronic structure problems such as calculating potential energy curves and producing benchmark values for reaction barriers. First, Variational and Diffusion Monte Carlo (VMC and DMC) methods using a trial wavefunction subject to the fixed node approximation were tested using the CASINO code.[1] Next, Full Configuration Interaction Quantum Monte Carlo (FCIQMC), along with its initiator extension (i-FCIQMC) were tested using the NECI code.[2] FCIQMC seeks the FCI energy for a specific basis set. At a reduced cost, the efficient i-FCIQMC method can be applied to systems in which the standard FCIQMC approach proves to be too costly. Since all of these methods are statistical approaches, uncertainties (error-bars) are introduced for each calculated energy. This study tests the performance of the methods relative to traditional quantum chemistry for some benchmark systems. References: [1] R. J. Needs et al., J. Phys.: Condensed Matter 22, 023201 (2010). [2] G. H. Booth et al., J. Chem. Phys. 131, 054106 (2009).

A New Monte Carlo Method for Estimating Marginal Likelihoods.

PubMed

Wang, Yu-Bo; Chen, Ming-Hui; Kuo, Lynn; Lewis, Paul O

2018-06-01

Evaluating the marginal likelihood in Bayesian analysis is essential for model selection. Estimators based on a single Markov chain Monte Carlo sample from the posterior distribution include the harmonic mean estimator and the inflated density ratio estimator. We propose a new class of Monte Carlo estimators based on this single Markov chain Monte Carlo sample. This class can be thought of as a generalization of the harmonic mean and inflated density ratio estimators using a partition weighted kernel (likelihood times prior). We show that our estimator is consistent and has better theoretical properties than the harmonic mean and inflated density ratio estimators. In addition, we provide guidelines on choosing optimal weights. Simulation studies were conducted to examine the empirical performance of the proposed estimator. We further demonstrate the desirable features of the proposed estimator with two real data sets: one is from a prostate cancer study using an ordinal probit regression model with latent variables; the other is for the power prior construction from two Eastern Cooperative Oncology Group phase III clinical trials using the cure rate survival model with similar objectives.

Patients With Spina Bifida and Their Caregivers' Feelings About Intermittent Bladder Catheterization in Brazil and Germany: A Correlational Study.

PubMed

Faleiros, Fabiana; Cordeiro, Adriana; Favoretto, Naira; Käppler, Christoph; Murray, Christine; Tate, Denise

A major complication for individuals with spina bifida (SB) is managing their neurogenic bladder. For many, this process evokes negative feelings associated with guilt, dependence, and lack of self-worth. The aim of the study was to compare feelings that hinder the performing of intermittent bladder catheterization reported by individuals with SB and their families in two countries of different sociocultural characteristics: Brazil and Germany. Quantitative and comparative study with convenience sampling. The sample comprised 200 SB patients and their caregivers, 100 from Brazil and 100 from Germany. When asked about the existence of negative feelings or ideas that may hinder the performance of key person responsible for IC, 155 (77.5%) participants did not report such feelings. On the other hand, 45 (22.5%) reported emotional difficulties; among these participants, 31 (69%) were Brazilians and 14 (31%) were Germans. Although emotional factors are important to the adjustment of using IC methods for bladder management, the majority of people with SB and their caregivers seem to report no major emotional difficulties with this process. Yet a considerable group of participants did report such emotional difficulties associated with fear and shame. Knowing more about the factors associated with such negative feelings can facilitate interactions, provide mutual aid, and assist with resolution of practical concerns related to intermittent bladder catheterization.

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo.

PubMed

McDaniel, T; D'Azevedo, E F; Li, Y W; Wong, K; Kent, P R C

2017-11-07

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is, therefore, formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with an application of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. This procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo, where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi-core central processing units and graphical processing units.

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo

NASA Astrophysics Data System (ADS)

McDaniel, T.; D'Azevedo, E. F.; Li, Y. W.; Wong, K.; Kent, P. R. C.

2017-11-01

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is, therefore, formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with an application of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. This procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo, where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi-core central processing units and graphical processing units.

Path integral Monte Carlo ground state approach: formalism, implementation, and applications

NASA Astrophysics Data System (ADS)

Yan, Yangqian; Blume, D.

2017-11-01

Monte Carlo techniques have played an important role in understanding strongly correlated systems across many areas of physics, covering a wide range of energy and length scales. Among the many Monte Carlo methods applicable to quantum mechanical systems, the path integral Monte Carlo approach with its variants has been employed widely. Since semi-classical or classical approaches will not be discussed in this review, path integral based approaches can for our purposes be divided into two categories: approaches applicable to quantum mechanical systems at zero temperature and approaches applicable to quantum mechanical systems at finite temperature. While these two approaches are related to each other, the underlying formulation and aspects of the algorithm differ. This paper reviews the path integral Monte Carlo ground state (PIGS) approach, which solves the time-independent Schrödinger equation. Specifically, the PIGS approach allows for the determination of expectation values with respect to eigen states of the few- or many-body Schrödinger equation provided the system Hamiltonian is known. The theoretical framework behind the PIGS algorithm, implementation details, and sample applications for fermionic systems are presented.

Monte Carlo method for calculating the radiation skyshine produced by electron accelerators

NASA Astrophysics Data System (ADS)

Kong, Chaocheng; Li, Quanfeng; Chen, Huaibi; Du, Taibin; Cheng, Cheng; Tang, Chuanxiang; Zhu, Li; Zhang, Hui; Pei, Zhigang; Ming, Shenjin

2005-06-01

Using the MCNP4C Monte Carlo code, the X-ray skyshine produced by 9 MeV, 15 MeV and 21 MeV electron linear accelerators were calculated respectively with a new two-step method combined with the split and roulette variance reduction technique. Results of the Monte Carlo simulation, the empirical formulas used for skyshine calculation and the dose measurements were analyzed and compared. In conclusion, the skyshine dose measurements agreed reasonably with the results computed by the Monte Carlo method, but deviated from computational results given by empirical formulas. The effect on skyshine dose caused by different structures of accelerator head is also discussed in this paper.

[Accuracy Check of Monte Carlo Simulation in Particle Therapy Using Gel Dosimeters].

PubMed

Furuta, Takuya

2017-01-01

Gel dosimeters are a three-dimensional imaging tool for dose distribution induced by radiations. They can be used for accuracy check of Monte Carlo simulation in particle therapy. An application was reviewed in this article. An inhomogeneous biological sample placing a gel dosimeter behind it was irradiated by carbon beam. The recorded dose distribution in the gel dosimeter reflected the inhomogeneity of the biological sample. Monte Carlo simulation was conducted by reconstructing the biological sample from its CT image. The accuracy of the particle transport by Monte Carlo simulation was checked by comparing the dose distribution in the gel dosimeter between simulation and experiment.

Instantons in Quantum Annealing: Thermally Assisted Tunneling Vs Quantum Monte Carlo Simulations

NASA Technical Reports Server (NTRS)

Jiang, Zhang; Smelyanskiy, Vadim N.; Boixo, Sergio; Isakov, Sergei V.; Neven, Hartmut; Mazzola, Guglielmo; Troyer, Matthias

2015-01-01

Recent numerical result (arXiv:1512.02206) from Google suggested that the D-Wave quantum annealer may have an asymptotic speed-up than simulated annealing, however, the asymptotic advantage disappears when it is compared to quantum Monte Carlo (a classical algorithm despite its name). We show analytically that the asymptotic scaling of quantum tunneling is exactly the same as the escape rate in quantum Monte Carlo for a class of problems. Thus, the Google result might be explained in our framework. We also found that the transition state in quantum Monte Carlo corresponds to the instanton solution in quantum tunneling problems, which is observed in numerical simulations.

CloudMC: a cloud computing application for Monte Carlo simulation.

PubMed

Miras, H; Jiménez, R; Miras, C; Gomà, C

2013-04-21

This work presents CloudMC, a cloud computing application-developed in Windows Azure®, the platform of the Microsoft® cloud-for the parallelization of Monte Carlo simulations in a dynamic virtual cluster. CloudMC is a web application designed to be independent of the Monte Carlo code in which the simulations are based-the simulations just need to be of the form: input files → executable → output files. To study the performance of CloudMC in Windows Azure®, Monte Carlo simulations with penelope were performed on different instance (virtual machine) sizes, and for different number of instances. The instance size was found to have no effect on the simulation runtime. It was also found that the decrease in time with the number of instances followed Amdahl's law, with a slight deviation due to the increase in the fraction of non-parallelizable time with increasing number of instances. A simulation that would have required 30 h of CPU on a single instance was completed in 48.6 min when executed on 64 instances in parallel (speedup of 37 ×). Furthermore, the use of cloud computing for parallel computing offers some advantages over conventional clusters: high accessibility, scalability and pay per usage. Therefore, it is strongly believed that cloud computing will play an important role in making Monte Carlo dose calculation a reality in future clinical practice.

Probabilistic learning of nonlinear dynamical systems using sequential Monte Carlo

NASA Astrophysics Data System (ADS)

Schön, Thomas B.; Svensson, Andreas; Murray, Lawrence; Lindsten, Fredrik

2018-05-01

Probabilistic modeling provides the capability to represent and manipulate uncertainty in data, models, predictions and decisions. We are concerned with the problem of learning probabilistic models of dynamical systems from measured data. Specifically, we consider learning of probabilistic nonlinear state-space models. There is no closed-form solution available for this problem, implying that we are forced to use approximations. In this tutorial we will provide a self-contained introduction to one of the state-of-the-art methods-the particle Metropolis-Hastings algorithm-which has proven to offer a practical approximation. This is a Monte Carlo based method, where the particle filter is used to guide a Markov chain Monte Carlo method through the parameter space. One of the key merits of the particle Metropolis-Hastings algorithm is that it is guaranteed to converge to the "true solution" under mild assumptions, despite being based on a particle filter with only a finite number of particles. We will also provide a motivating numerical example illustrating the method using a modeling language tailored for sequential Monte Carlo methods. The intention of modeling languages of this kind is to open up the power of sophisticated Monte Carlo methods-including particle Metropolis-Hastings-to a large group of users without requiring them to know all the underlying mathematical details.

MC3: Multi-core Markov-chain Monte Carlo code

NASA Astrophysics Data System (ADS)

Cubillos, Patricio; Harrington, Joseph; Lust, Nate; Foster, AJ; Stemm, Madison; Loredo, Tom; Stevenson, Kevin; Campo, Chris; Hardin, Matt; Hardy, Ryan

2016-10-01

MC3 (Multi-core Markov-chain Monte Carlo) is a Bayesian statistics tool that can be executed from the shell prompt or interactively through the Python interpreter with single- or multiple-CPU parallel computing. It offers Markov-chain Monte Carlo (MCMC) posterior-distribution sampling for several algorithms, Levenberg-Marquardt least-squares optimization, and uniform non-informative, Jeffreys non-informative, or Gaussian-informative priors. MC3 can share the same value among multiple parameters and fix the value of parameters to constant values, and offers Gelman-Rubin convergence testing and correlated-noise estimation with time-averaging or wavelet-based likelihood estimation methods.

Perturbative two- and three-loop coefficients from large β Monte Carlo

NASA Astrophysics Data System (ADS)

Lepage, G. P.; Mackenzie, P. B.; Shakespeare, N. H.; Trottier, H. D.

Perturbative coefficients for Wilson loops and the static quark self-energy are extracted from Monte Carlo simulations at large β on finite volumes, where all the lattice momenta are large. The Monte Carlo results are in excellent agreement with perturbation theory through second order. New results for third order coefficients are reported. Twisted boundary conditions are used to eliminate zero modes and to suppress Z3 tunneling.

Full Configuration Interaction Quantum Monte Carlo and Diffusion Monte Carlo: A Comparative Study of the 3D Homogeneous Electron Gas

NASA Astrophysics Data System (ADS)

Shepherd, James J.; López Ríos, Pablo; Needs, Richard J.; Drummond, Neil D.; Mohr, Jennifer A.-F.; Booth, George H.; Grüneis, Andreas; Kresse, Georg; Alavi, Ali

2013-03-01

Full configuration interaction quantum Monte Carlo1 (FCIQMC) and its initiator adaptation2 allow for exact solutions to the Schrödinger equation to be obtained within a finite-basis wavefunction ansatz. In this talk, we explore an application of FCIQMC to the homogeneous electron gas (HEG). In particular we use these exact finite-basis energies to compare with approximate quantum chemical calculations from the VASP code3. After removing the basis set incompleteness error by extrapolation4,5, we compare our energies with state-of-the-art diffusion Monte Carlo calculations from the CASINO package6. Using a combined approach of the two quantum Monte Carlo methods, we present the highest-accuracy thermodynamic (infinite-particle) limit energies for the HEG achieved to date. 1 G. H. Booth, A. Thom, and A. Alavi, J. Chem. Phys. 131, 054106 (2009). 2 D. Cleland, G. H. Booth, and A. Alavi, J. Chem. Phys. 132, 041103 (2010). 3 www.vasp.at (2012). 4 J. J. Shepherd, A. Grüneis, G. H. Booth, G. Kresse, and A. Alavi, Phys. Rev. B. 86, 035111 (2012). 5 J. J. Shepherd, G. H. Booth, and A. Alavi, J. Chem. Phys. 136, 244101 (2012). 6 R. Needs, M. Towler, N. Drummond, and P. L. Ríos, J. Phys.: Condensed Matter 22, 023201 (2010).

The influence of social adjustment on normative and risky health behaviors in emerging adults with spina bifida.

PubMed

Murray, Caitlin B; Lennon, Jaclyn M; Devine, Katie A; Holmbeck, Grayson N; Klages, Kimberly; Potthoff, Lauren M

2014-10-01

To understand the rates of normative and risky health behaviors and the influence of prior and current social adjustment on health risk behaviors in emerging adults with spina bifida (SB). These data are part of a larger longitudinal study of youth with SB; at ages 18-19, 50 emerging adults with SB and 60 typically developing (TD) youth participated. Social adjustment was measured at ages 12/13, 14/15, 16/17, and 18/19. Substance use and sexual activity were self-reported by emerging adults. The SB group reported similar frequencies (i.e., number of days in the previous month) of cigarette and marijuana use. Fewer individuals with SB reported initiation of both alcohol use (i.e., ever used) and sexual activity (i.e., ever had sex) compared to TD peers. The SB group also reported less frequent alcohol use and fewer sexual partners. Better social adjustment during early adolescence (ages 12/13) predicted more frequent alcohol use and a greater number of sexual partners for all youth. Social adjustment also mediated the effect of group status on health risk behaviors. Emerging adults with SB lag behind TD peers in terms of normative initiation of alcohol use and sexual activity. However, this population participates in some risky health behaviors at similar rates compared to their TD peers (e.g., smoking). Youths' health risk behaviors may be influenced by their level of social adjustment. A challenge for future interventions for this population will be finding methods of improving social functioning without increasing the rate of health risk behavior.

Estimating statistical uncertainty of Monte Carlo efficiency-gain in the context of a correlated sampling Monte Carlo code for brachytherapy treatment planning with non-normal dose distribution.

PubMed

Mukhopadhyay, Nitai D; Sampson, Andrew J; Deniz, Daniel; Alm Carlsson, Gudrun; Williamson, Jeffrey; Malusek, Alexandr

2012-01-01

Correlated sampling Monte Carlo methods can shorten computing times in brachytherapy treatment planning. Monte Carlo efficiency is typically estimated via efficiency gain, defined as the reduction in computing time by correlated sampling relative to conventional Monte Carlo methods when equal statistical uncertainties have been achieved. The determination of the efficiency gain uncertainty arising from random effects, however, is not a straightforward task specially when the error distribution is non-normal. The purpose of this study is to evaluate the applicability of the F distribution and standardized uncertainty propagation methods (widely used in metrology to estimate uncertainty of physical measurements) for predicting confidence intervals about efficiency gain estimates derived from single Monte Carlo runs using fixed-collision correlated sampling in a simplified brachytherapy geometry. A bootstrap based algorithm was used to simulate the probability distribution of the efficiency gain estimates and the shortest 95% confidence interval was estimated from this distribution. It was found that the corresponding relative uncertainty was as large as 37% for this particular problem. The uncertainty propagation framework predicted confidence intervals reasonably well; however its main disadvantage was that uncertainties of input quantities had to be calculated in a separate run via a Monte Carlo method. The F distribution noticeably underestimated the confidence interval. These discrepancies were influenced by several photons with large statistical weights which made extremely large contributions to the scored absorbed dose difference. The mechanism of acquiring high statistical weights in the fixed-collision correlated sampling method was explained and a mitigation strategy was proposed. Copyright © 2011 Elsevier Ltd. All rights reserved.

LMC: Logarithmantic Monte Carlo

NASA Astrophysics Data System (ADS)

Mantz, Adam B.

2017-06-01

LMC is a Markov Chain Monte Carlo engine in Python that implements adaptive Metropolis-Hastings and slice sampling, as well as the affine-invariant method of Goodman & Weare, in a flexible framework. It can be used for simple problems, but the main use case is problems where expensive likelihood evaluations are provided by less flexible third-party software, which benefit from parallelization across many nodes at the sampling level. The parallel/adaptive methods use communication through MPI, or alternatively by writing/reading files, and mostly follow the approaches pioneered by CosmoMC (ascl:1106.025).

Metallic lithium by quantum Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sugiyama, G.; Zerah, G.; Alder, B.J.

Lithium was chosen as the simplest known metal for the first application of quantum Monte Carlo methods in order to evaluate the accuracy of conventional one-electron band theories. Lithium has been extensively studied using such techniques. Band theory calculations have certain limitations in general and specifically in their application to lithium. Results depend on such factors as charge shape approximations (muffin tins), pseudopotentials (a special problem for lithium where the lack of rho core states requires a strong pseudopotential), and the form and parameters chosen for the exchange potential. The calculations are all one-electron methods in which the correlation effectsmore » are included in an ad hoc manner. This approximation may be particularly poor in the high compression regime, where the core states become delocalized. Furthermore, band theory provides only self-consistent results rather than strict limits on the energies. The quantum Monte Carlo method is a totally different technique using a many-body rather than a mean field approach which yields an upper bound on the energies. 18 refs., 4 figs., 1 tab.« less

How Monte Carlo heuristics aid to identify the physical processes of drug release kinetics.

PubMed

Lecca, Paola

2018-01-01

We implement a Monte Carlo heuristic algorithm to model drug release from a solid dosage form. We show that with Monte Carlo simulations it is possible to identify and explain the causes of the unsatisfactory predictive power of current drug release models. It is well known that the power-law, the exponential models, as well as those derived from or inspired by them accurately reproduce only the first 60% of the release curve of a drug from a dosage form. In this study, by using Monte Carlo simulation approaches, we show that these models fit quite accurately almost the entire release profile when the release kinetics is not governed by the coexistence of different physico-chemical mechanisms. We show that the accuracy of the traditional models are comparable with those of Monte Carlo heuristics when these heuristics approximate and oversimply the phenomenology of drug release. This observation suggests to develop and use novel Monte Carlo simulation heuristics able to describe the complexity of the release kinetics, and consequently to generate data more similar to those observed in real experiments. Implementing Monte Carlo simulation heuristics of the drug release phenomenology may be much straightforward and efficient than hypothesizing and implementing from scratch complex mathematical models of the physical processes involved in drug release. Identifying and understanding through simulation heuristics what processes of this phenomenology reproduce the observed data and then formalize them in mathematics may allow avoiding time-consuming, trial-error based regression procedures. Three bullet points, highlighting the customization of the procedure. •An efficient heuristics based on Monte Carlo methods for simulating drug release from solid dosage form encodes is presented. It specifies the model of the physical process in a simple but accurate way in the formula of the Monte Carlo Micro Step (MCS) time interval.•Given the experimentally observed curve of

Radiotherapy Monte Carlo simulation using cloud computing technology.

PubMed

Poole, C M; Cornelius, I; Trapp, J V; Langton, C M

2012-12-01

Cloud computing allows for vast computational resources to be leveraged quickly and easily in bursts as and when required. Here we describe a technique that allows for Monte Carlo radiotherapy dose calculations to be performed using GEANT4 and executed in the cloud, with relative simulation cost and completion time evaluated as a function of machine count. As expected, simulation completion time decreases as 1/n for n parallel machines, and relative simulation cost is found to be optimal where n is a factor of the total simulation time in hours. Using the technique, we demonstrate the potential usefulness of cloud computing as a solution for rapid Monte Carlo simulation for radiotherapy dose calculation without the need for dedicated local computer hardware as a proof of principal.

Monte Carlo modelling the dosimetric effects of electrode material on diamond detectors.

PubMed

Baluti, Florentina; Deloar, Hossain M; Lansley, Stuart P; Meyer, Juergen

2015-03-01

Diamond detectors for radiation dosimetry were modelled using the EGSnrc Monte Carlo code to investigate the influence of electrode material and detector orientation on the absorbed dose. The small dimensions of the electrode/diamond/electrode detector structure required very thin voxels and the use of non-standard DOSXYZnrc Monte Carlo model parameters. The interface phenomena was investigated by simulating a 6 MV beam and detectors with different electrode materials, namely Al, Ag, Cu and Au, with thickens of 0.1 µm for the electrodes and 0.1 mm for the diamond, in both perpendicular and parallel detector orientation with regards to the incident beam. The smallest perturbations were observed for the parallel detector orientation and Al electrodes (Z = 13). In summary, EGSnrc Monte Carlo code is well suited for modelling small detector geometries. The Monte Carlo model developed is a useful tool to investigate the dosimetric effects caused by different electrode materials. To minimise perturbations cause by the detector electrodes, it is recommended that the electrodes should be made from a low-atomic number material and placed parallel to the beam direction.

Perturbative two- and three-loop coefficients from large b Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

G.P. Lepage; P.B. Mackenzie; N.H. Shakespeare

1999-10-18

Perturbative coefficients for Wilson loops and the static quark self-energy are extracted from Monte Carlo simulations at large {beta} on finite volumes, where all the lattice momenta are large. The Monte Carlo results are in excellent agreement with perturbation theory through second order. New results for third order coefficients are reported. Twisted boundary conditions are used to eliminate zero modes and to suppress Z{sub 3} tunneling.

Scalable Domain Decomposed Monte Carlo Particle Transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Brien, Matthew Joseph

2013-12-05

In this dissertation, we present the parallel algorithms necessary to run domain decomposed Monte Carlo particle transport on large numbers of processors (millions of processors). Previous algorithms were not scalable, and the parallel overhead became more computationally costly than the numerical simulation.

Pushing the limits of Monte Carlo simulations for the three-dimensional Ising model

NASA Astrophysics Data System (ADS)

Ferrenberg, Alan M.; Xu, Jiahao; Landau, David P.

2018-04-01

While the three-dimensional Ising model has defied analytic solution, various numerical methods like Monte Carlo, Monte Carlo renormalization group, and series expansion have provided precise information about the phase transition. Using Monte Carlo simulation that employs the Wolff cluster flipping algorithm with both 32-bit and 53-bit random number generators and data analysis with histogram reweighting and quadruple precision arithmetic, we have investigated the critical behavior of the simple cubic Ising Model, with lattice sizes ranging from 163 to 10243. By analyzing data with cross correlations between various thermodynamic quantities obtained from the same data pool, e.g., logarithmic derivatives of magnetization and derivatives of magnetization cumulants, we have obtained the critical inverse temperature Kc=0.221 654 626 (5 ) and the critical exponent of the correlation length ν =0.629 912 (86 ) with precision that exceeds all previous Monte Carlo estimates.

Characterization, antibacterial, and neurotoxic effect of Green synthesized nanosilver using Ziziphus spina Christi aqueous leaf extract collected from Riyadh, Saudi Arabia

NASA Astrophysics Data System (ADS)

El-Ansary, Afaf; Warsy, Arjumand; Daghestani, Maha; Merghani, Nada M.; Al-Dbass, Abeer; Bukhari, Wadha; Al-Ojayan, Badryah; Ibrahim, Eiman M.; Al-Qahtani, Asma M.; Shafi Bhat, Ramesa

2018-02-01

The current study aims to synthesize silver nanoparticles using Ziziphus spina Christi (ZSC) or (Sidr) aqueous leaf extract collected from Riyadh, Saudi Arabia. The green synthesis of silver nanoparticles using sidr leaves extract was successful. Production of silver nanoparticles was confirmed through UV-vis Spectrophotometer, particles size and zeta potential analysis, Infra-red spectroscopy, Scanning, and Transmission Electron Microscope (SEM and TEM). The UV-visible spectra showed that the absorption peak existed at 400 nm. SEM analysis showed that the synthesized AgNPs were spherical but in slightly aggregated form. TEM demonstrated different size range of 4-33 nm with an average size of 13. The element analysis profile showed silver signal together with oxygen, calcium, and potassium peaks which might be related to the plant structure. Biological effects of the synthesized AgNPs exhibit satisfactory inhibitory effect against ten tested microorganisms. It inhibited the growth of 5 gram-positive and five gram-negative bacteria. Moreover, AgNPs demonstrated a synergistic effect on the neurotoxicity induced in rat pups with orally administered methyl mercury (MeHg). The present study showed that AgNPs prepared from ZSC might be a promising antimicrobial agent for successful treatment of bacterial infection in intensive care units (ICU) especially in case of antibiotic resistance.

EFFECTIVENESS OF AN UPPER EXTREMITY EXERCISE DEVICE AND TEXT MESSAGE REMINDERS TO EXERCISE IN ADULTS WITH SPINA BIFIDA: A PILOT STUDY

PubMed Central

Crytzer, Theresa M.; Dicianno, Brad E.; Fairman, Andrea D.

2013-01-01

Background Obesity, deconditioning, cognitive impairment, and poor exercise tolerance are health issues concerning adults with spina bifida (SB). Our aim is to describe exercise participation and identify motivating tactics and exercise devices that increase participation. Design In a quasi-experimental randomized crossover design, the GameCycle was compared to a Saratoga Silver I arm ergometer. Personalized free or low cost text/voice message reminders to exercise were sent. Methods Nineteen young adults with SB were assigned to either the GameCycle or Saratoga exercise group. Within each group, participants were randomized to receive reminders to exercise, or no reminders, then crossed over to the opposite message group after eight weeks. Before and after a 16 week exercise program we collected anthropometric, metabolic, exercise testing and questionnaire data, and recorded participation. Results Miles traveled by the GameCycle group were significantly higher than the Saratoga exercise groups. No significant differences were found in participation between the message reminder groups. Low participation rates were seen overall. Conclusions Those using the GameCycle traveled more miles. Barriers to exercise participation may have superseded ability to motivate adults with SB to exercise even with electronic reminders. Support from therapists to combat deconditioning and develop coping skills may be needed. PMID:24620701

MCNP (Monte Carlo Neutron Photon) capabilities for nuclear well logging calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forster, R.A.; Little, R.C.; Briesmeister, J.F.

The Los Alamos Radiation Transport Code System (LARTCS) consists of state-of-the-art Monte Carlo and discrete ordinates transport codes and data libraries. The general-purpose continuous-energy Monte Carlo code MCNP (Monte Carlo Neutron Photon), part of the LARTCS, provides a computational predictive capability for many applications of interest to the nuclear well logging community. The generalized three-dimensional geometry of MCNP is well suited for borehole-tool models. SABRINA, another component of the LARTCS, is a graphics code that can be used to interactively create a complex MCNP geometry. Users can define many source and tally characteristics with standard MCNP features. The time-dependent capabilitymore » of the code is essential when modeling pulsed sources. Problems with neutrons, photons, and electrons as either single particle or coupled particles can be calculated with MCNP. The physics of neutron and photon transport and interactions is modeled in detail using the latest available cross-section data. A rich collections of variance reduction features can greatly increase the efficiency of a calculation. MCNP is written in FORTRAN 77 and has been run on variety of computer systems from scientific workstations to supercomputers. The next production version of MCNP will include features such as continuous-energy electron transport and a multitasking option. Areas of ongoing research of interest to the well logging community include angle biasing, adaptive Monte Carlo, improved discrete ordinates capabilities, and discrete ordinates/Monte Carlo hybrid development. Los Alamos has requested approval by the Department of Energy to create a Radiation Transport Computational Facility under their User Facility Program to increase external interactions with industry, universities, and other government organizations. 21 refs.« less

Pattern Recognition for a Flight Dynamics Monte Carlo Simulation

NASA Technical Reports Server (NTRS)

Restrepo, Carolina; Hurtado, John E.

2011-01-01

The design, analysis, and verification and validation of a spacecraft relies heavily on Monte Carlo simulations. Modern computational techniques are able to generate large amounts of Monte Carlo data but flight dynamics engineers lack the time and resources to analyze it all. The growing amounts of data combined with the diminished available time of engineers motivates the need to automate the analysis process. Pattern recognition algorithms are an innovative way of analyzing flight dynamics data efficiently. They can search large data sets for specific patterns and highlight critical variables so analysts can focus their analysis efforts. This work combines a few tractable pattern recognition algorithms with basic flight dynamics concepts to build a practical analysis tool for Monte Carlo simulations. Current results show that this tool can quickly and automatically identify individual design parameters, and most importantly, specific combinations of parameters that should be avoided in order to prevent specific system failures. The current version uses a kernel density estimation algorithm and a sequential feature selection algorithm combined with a k-nearest neighbor classifier to find and rank important design parameters. This provides an increased level of confidence in the analysis and saves a significant amount of time.

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo

DOE PAGES

McDaniel, Tyler; D’Azevedo, Ed F.; Li, Ying Wai; ...

2017-11-07

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is therefore formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with applicationmore » of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. Here this procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi- core CPUs and GPUs.« less

Delayed Slater determinant update algorithms for high efficiency quantum Monte Carlo

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDaniel, Tyler; D’Azevedo, Ed F.; Li, Ying Wai

Within ab initio Quantum Monte Carlo simulations, the leading numerical cost for large systems is the computation of the values of the Slater determinants in the trial wavefunction. Each Monte Carlo step requires finding the determinant of a dense matrix. This is most commonly iteratively evaluated using a rank-1 Sherman-Morrison updating scheme to avoid repeated explicit calculation of the inverse. The overall computational cost is therefore formally cubic in the number of electrons or matrix size. To improve the numerical efficiency of this procedure, we propose a novel multiple rank delayed update scheme. This strategy enables probability evaluation with applicationmore » of accepted moves to the matrices delayed until after a predetermined number of moves, K. The accepted events are then applied to the matrices en bloc with enhanced arithmetic intensity and computational efficiency via matrix-matrix operations instead of matrix-vector operations. Here this procedure does not change the underlying Monte Carlo sampling or its statistical efficiency. For calculations on large systems and algorithms such as diffusion Monte Carlo where the acceptance ratio is high, order of magnitude improvements in the update time can be obtained on both multi- core CPUs and GPUs.« less

Applying Monte Carlo Simulation to Launch Vehicle Design and Requirements Analysis

NASA Technical Reports Server (NTRS)

Hanson, J. M.; Beard, B. B.

2010-01-01

This Technical Publication (TP) is meant to address a number of topics related to the application of Monte Carlo simulation to launch vehicle design and requirements analysis. Although the focus is on a launch vehicle application, the methods may be applied to other complex systems as well. The TP is organized so that all the important topics are covered in the main text, and detailed derivations are in the appendices. The TP first introduces Monte Carlo simulation and the major topics to be discussed, including discussion of the input distributions for Monte Carlo runs, testing the simulation, how many runs are necessary for verification of requirements, what to do if results are desired for events that happen only rarely, and postprocessing, including analyzing any failed runs, examples of useful output products, and statistical information for generating desired results from the output data. Topics in the appendices include some tables for requirements verification, derivation of the number of runs required and generation of output probabilistic data with consumer risk included, derivation of launch vehicle models to include possible variations of assembled vehicles, minimization of a consumable to achieve a two-dimensional statistical result, recontact probability during staging, ensuring duplicated Monte Carlo random variations, and importance sampling.

Bold Diagrammatic Monte Carlo for Fermionic and Fermionized Systems

NASA Astrophysics Data System (ADS)

Svistunov, Boris

2013-03-01

In three different fermionic cases--repulsive Hubbard model, resonant fermions, and fermionized spins-1/2 (on triangular lattice)--we observe the phenomenon of sign blessing: Feynman diagrammatic series features finite convergence radius despite factorial growth of the number of diagrams with diagram order. Bold diagrammatic Monte Carlo technique allows us to sample millions of skeleton Feynman diagrams. With the universal fermionization trick we can fermionize essentially any (bosonic, spin, mixed, etc.) lattice system. The combination of fermionization and Bold diagrammatic Monte Carlo yields a universal first-principle approach to strongly correlated lattice systems, provided the sign blessing is a generic fermionic phenomenon. Supported by NSF and DARPA

Understanding quantum tunneling using diffusion Monte Carlo simulations

NASA Astrophysics Data System (ADS)

Inack, E. M.; Giudici, G.; Parolini, T.; Santoro, G.; Pilati, S.

2018-03-01

In simple ferromagnetic quantum Ising models characterized by an effective double-well energy landscape the characteristic tunneling time of path-integral Monte Carlo (PIMC) simulations has been shown to scale as the incoherent quantum-tunneling time, i.e., as 1 /Δ2 , where Δ is the tunneling gap. Since incoherent quantum tunneling is employed by quantum annealers (QAs) to solve optimization problems, this result suggests that there is no quantum advantage in using QAs with respect to quantum Monte Carlo (QMC) simulations. A counterexample is the recently introduced shamrock model (Andriyash and Amin, arXiv:1703.09277), where topological obstructions cause an exponential slowdown of the PIMC tunneling dynamics with respect to incoherent quantum tunneling, leaving open the possibility for potential quantum speedup, even for stoquastic models. In this work we investigate the tunneling time of projective QMC simulations based on the diffusion Monte Carlo (DMC) algorithm without guiding functions, showing that it scales as 1 /Δ , i.e., even more favorably than the incoherent quantum-tunneling time, both in a simple ferromagnetic system and in the more challenging shamrock model. However, a careful comparison between the DMC ground-state energies and the exact solution available for the transverse-field Ising chain indicates an exponential scaling of the computational cost required to keep a fixed relative error as the system size increases.

38 CFR 21.8012 - Vocational training program for certain children of Vietnam veterans and veterans with covered...

Code of Federal Regulations, 2014 CFR

2014-07-01

... program for certain children of Vietnam veterans and veterans with covered service in Korea-spina bifida... Rehabilitation for Certain Children of Vietnam Veterans and Veterans with Covered Service in Korea-Spina Bifida... Vietnam veterans and veterans with covered service in Korea—spina bifida and covered birth defects. VA...

38 CFR 21.8012 - Vocational training program for certain children of Vietnam veterans and veterans with covered...

Code of Federal Regulations, 2013 CFR

2013-07-01

... program for certain children of Vietnam veterans and veterans with covered service in Korea-spina bifida... Rehabilitation for Certain Children of Vietnam Veterans and Veterans with Covered Service in Korea-Spina Bifida... Vietnam veterans and veterans with covered service in Korea—spina bifida and covered birth defects. VA...

38 CFR 21.8012 - Vocational training program for certain children of Vietnam veterans and veterans with covered...

Code of Federal Regulations, 2012 CFR

2012-07-01

... program for certain children of Vietnam veterans and veterans with covered service in Korea-spina bifida... Rehabilitation for Certain Children of Vietnam Veterans and Veterans with Covered Service in Korea-Spina Bifida... Vietnam veterans and veterans with covered service in Korea—spina bifida and covered birth defects. VA...

38 CFR 21.8012 - Vocational training program for certain children of Vietnam veterans and veterans with covered...

Code of Federal Regulations, 2011 CFR

2011-07-01

... program for certain children of Vietnam veterans and veterans with covered service in Korea-spina bifida... Rehabilitation for Certain Children of Vietnam Veterans and Veterans with Covered Service in Korea-Spina Bifida... Vietnam veterans and veterans with covered service in Korea—spina bifida and covered birth defects. VA...

Advanced Monte Carlo methods for thermal radiation transport

NASA Astrophysics Data System (ADS)

Wollaber, Allan B.

During the past 35 years, the Implicit Monte Carlo (IMC) method proposed by Fleck and Cummings has been the standard Monte Carlo approach to solving the thermal radiative transfer (TRT) equations. However, the IMC equations are known to have accuracy limitations that can produce unphysical solutions. In this thesis, we explicitly provide the IMC equations with a Monte Carlo interpretation by including particle weight as one of its arguments. We also develop and test a stability theory for the 1-D, gray IMC equations applied to a nonlinear problem. We demonstrate that the worst case occurs for 0-D problems, and we extend the results to a stability algorithm that may be used for general linearizations of the TRT equations. We derive gray, Quasidiffusion equations that may be deterministically solved in conjunction with IMC to obtain an inexpensive, accurate estimate of the temperature at the end of the time step. We then define an average temperature T* to evaluate the temperature-dependent problem data in IMC, and we demonstrate that using T* is more accurate than using the (traditional) beginning-of-time-step temperature. We also propose an accuracy enhancement to the IMC equations: the use of a time-dependent "Fleck factor". This Fleck factor can be considered an automatic tuning of the traditionally defined user parameter alpha, which generally provides more accurate solutions at an increased cost relative to traditional IMC. We also introduce a global weight window that is proportional to the forward scalar intensity calculated by the Quasidiffusion method. This weight window improves the efficiency of the IMC calculation while conserving energy. All of the proposed enhancements are tested in 1-D gray and frequency-dependent problems. These enhancements do not unconditionally eliminate the unphysical behavior that can be seen in the IMC calculations. However, for fixed spatial and temporal grids, they suppress them and clearly work to make the solution more

Effect of Preschool Working Memory, Language, and Narrative Abilities on Inferential Comprehension at School-Age in Children with Spina Bifida Myelomeningocele and Typically Developing Children

PubMed Central

Pike, Meredith; Swank, Paul; Taylor, Heather; Landry, Susan; Barnes, Marcia A.

2014-01-01

Children with spina bifida myelomeningocele (SBM) are more likely to display a pattern of good-decoding/poor comprehension than their neurologically intact peers. The goals of the current study were to (1) examine the cognitive origins of one of the component skills of comprehension, bridging inferences, from a developmental perspective and (2) to test the effects of those relations on reading comprehension achievement. Data from a sample of children with SBM and a control group (n = 78) who participated in a longitudinal study were taken from age 36-month and 9.5-year time points. A multiple mediation model provided evidence that three preschool cognitive abilities (working memory/inhibitory control, oral comprehension, narrative recall), could partially explain the relation between group and bridging inference skill. A second mediation model supported that each of the 36-month abilities had an indirect effect on reading comprehension through bridging inference skill. Findings contribute to an understanding of both typical and atypical comprehension development, blending theories from the developmental, cognitive, and neuropsychological literature. PMID:23388065

Effect of preschool working memory, language, and narrative abilities on inferential comprehension at school-age in children with spina bifida myelomeningocele and typically developing children.

PubMed

Pike, Meredith; Swank, Paul; Taylor, Heather; Landry, Susan; Barnes, Marcia A

2013-04-01

Children with spina bifida myelomeningocele (SBM) are more likely to display a pattern of good-decoding/poor comprehension than their neurologically intact peers. The goals of the current study were to (1) examine the cognitive origins of one of the component skills of comprehension, bridging inferences, from a developmental perspective and (2) to test the effects of those relations on reading comprehension achievement. Data from a sample of children with SBM and a control group (n = 78) who participated in a longitudinal study were taken from age 36-month and 9.5-year time points. A multiple mediation model provided evidence that three preschool cognitive abilities (working memory/inhibitory control, oral comprehension, narrative recall), could partially explain the relation between group and bridging inference skill. A second mediation model supported that each of the 36-month abilities had an indirect effect on reading comprehension through bridging inference skill. Findings contribute to an understanding of both typical and atypical comprehension development, blending theories from the developmental, cognitive, and neuropsychological literature.

Geologic evolution of the Akna Montes-Atropos Tessera region, Venus

NASA Astrophysics Data System (ADS)

Marinangeli, Lucia; Gilmore, Martha S.

2000-05-01

The investigated area comprises an arcuate mountain belt, Akna Montes, in Western Ishtar Terra, associated with an outboard plateau, Atropos Tessera, to the west and a volcanic plateau, Lakshmi Planum, to the east. Eight geologic units have been recognized on the basis of their geomorphic and structural characteristics as they appear on Magellan radar images. Our stratigraphic analysis shows that the geological evolution of the study area can be explained by four main steps: (1) formation of the older substrata of Atropos Tessera and Lakshmi, (2) extensive plains emplacement, (3) an orogenic phase including the formation of Akna Montes, and (4) local emplacement of younger plains. The tectonic evolution shows a deformational sequence characterized by contraction, shear, and topographic relaxation. This sequence is interpreted to be a consequence of the variation of crustal stresses and crustal thickening during orogenic events as observed for terrestrial high plateaus associated with a mountain belt (i.e., Himalaya and Tibet, Andes and Altiplano). In order to estimate the amount of crustal shortening associated with the Akna Montes, we considered two end-members for structural style of the mountain belt: a symmetric fold model and fault-bend fold model. The models are theoretical because terrestrial orogenic belts are often formed by a combination of different compressional structures. However, symmetric and fault-bend faults represent the minimum and maximum crustal shortening, respectively, and thus they do place bounds on the amount of strain recorded by Akna Montes. The first model yields a shortening value less than 1%, whereas a range of 17-34% is derived for the second model. The large difference between these values underscores the importance of fold geometries for estimating strain and to place constraints on geodynamic models for mountain belt formation. On the basis of our study we think that a combination of mantle downwelling and horizontal convergence

Fast GPU-based Monte Carlo simulations for LDR prostate brachytherapy.

PubMed

Bonenfant, Éric; Magnoux, Vincent; Hissoiny, Sami; Ozell, Benoît; Beaulieu, Luc; Després, Philippe

2015-07-07

The aim of this study was to evaluate the potential of bGPUMCD, a Monte Carlo algorithm executed on Graphics Processing Units (GPUs), for fast dose calculations in permanent prostate implant dosimetry. It also aimed to validate a low dose rate brachytherapy source in terms of TG-43 metrics and to use this source to compute dose distributions for permanent prostate implant in very short times. The physics of bGPUMCD was reviewed and extended to include Rayleigh scattering and fluorescence from photoelectric interactions for all materials involved. The radial and anisotropy functions were obtained for the Nucletron SelectSeed in TG-43 conditions. These functions were compared to those found in the MD Anderson Imaging and Radiation Oncology Core brachytherapy source registry which are considered the TG-43 reference values. After appropriate calibration of the source, permanent prostate implant dose distributions were calculated for four patients and compared to an already validated Geant4 algorithm. The radial function calculated from bGPUMCD showed excellent agreement (differences within 1.3%) with TG-43 accepted values. The anisotropy functions at r = 1 cm and r = 4 cm were within 2% of TG-43 values for angles over 17.5°. For permanent prostate implants, Monte Carlo-based dose distributions with a statistical uncertainty of 1% or less for the target volume were obtained in 30 s or less for 1 × 1 × 1 mm(3) calculation grids. Dosimetric indices were very similar (within 2.7%) to those obtained with a validated, independent Monte Carlo code (Geant4) performing the calculations for the same cases in a much longer time (tens of minutes to more than a hour). bGPUMCD is a promising code that lets envision the use of Monte Carlo techniques in a clinical environment, with sub-minute execution times on a standard workstation. Future work will explore the use of this code with an inverse planning method to provide a complete Monte Carlo-based planning solution.

Fast GPU-based Monte Carlo simulations for LDR prostate brachytherapy

NASA Astrophysics Data System (ADS)

Bonenfant, Éric; Magnoux, Vincent; Hissoiny, Sami; Ozell, Benoît; Beaulieu, Luc; Després, Philippe

2015-07-01

The aim of this study was to evaluate the potential of bGPUMCD, a Monte Carlo algorithm executed on Graphics Processing Units (GPUs), for fast dose calculations in permanent prostate implant dosimetry. It also aimed to validate a low dose rate brachytherapy source in terms of TG-43 metrics and to use this source to compute dose distributions for permanent prostate implant in very short times. The physics of bGPUMCD was reviewed and extended to include Rayleigh scattering and fluorescence from photoelectric interactions for all materials involved. The radial and anisotropy functions were obtained for the Nucletron SelectSeed in TG-43 conditions. These functions were compared to those found in the MD Anderson Imaging and Radiation Oncology Core brachytherapy source registry which are considered the TG-43 reference values. After appropriate calibration of the source, permanent prostate implant dose distributions were calculated for four patients and compared to an already validated Geant4 algorithm. The radial function calculated from bGPUMCD showed excellent agreement (differences within 1.3%) with TG-43 accepted values. The anisotropy functions at r = 1 cm and r = 4 cm were within 2% of TG-43 values for angles over 17.5°. For permanent prostate implants, Monte Carlo-based dose distributions with a statistical uncertainty of 1% or less for the target volume were obtained in 30 s or less for 1 × 1 × 1 mm3 calculation grids. Dosimetric indices were very similar (within 2.7%) to those obtained with a validated, independent Monte Carlo code (Geant4) performing the calculations for the same cases in a much longer time (tens of minutes to more than a hour). bGPUMCD is a promising code that lets envision the use of Monte Carlo techniques in a clinical environment, with sub-minute execution times on a standard workstation. Future work will explore the use of this code with an inverse planning method to provide a complete Monte Carlo-based planning solution.

Multilevel Sequential Monte Carlo Samplers for Normalizing Constants

DOE PAGES

Moral, Pierre Del; Jasra, Ajay; Law, Kody J. H.; ...

2017-08-24

This article considers the sequential Monte Carlo (SMC) approximation of ratios of normalizing constants associated to posterior distributions which in principle rely on continuum models. Therefore, the Monte Carlo estimation error and the discrete approximation error must be balanced. A multilevel strategy is utilized to substantially reduce the cost to obtain a given error level in the approximation as compared to standard estimators. Two estimators are considered and relative variance bounds are given. The theoretical results are numerically illustrated for two Bayesian inverse problems arising from elliptic partial differential equations (PDEs). The examples involve the inversion of observations of themore » solution of (i) a 1-dimensional Poisson equation to infer the diffusion coefficient, and (ii) a 2-dimensional Poisson equation to infer the external forcing.« less

Continuous-time quantum Monte Carlo impurity solvers

NASA Astrophysics Data System (ADS)

Gull, Emanuel; Werner, Philipp; Fuchs, Sebastian; Surer, Brigitte; Pruschke, Thomas; Troyer, Matthias

2011-04-01

Continuous-time quantum Monte Carlo impurity solvers are algorithms that sample the partition function of an impurity model using diagrammatic Monte Carlo techniques. The present paper describes codes that implement the interaction expansion algorithm originally developed by Rubtsov, Savkin, and Lichtenstein, as well as the hybridization expansion method developed by Werner, Millis, Troyer, et al. These impurity solvers are part of the ALPS-DMFT application package and are accompanied by an implementation of dynamical mean-field self-consistency equations for (single orbital single site) dynamical mean-field problems with arbitrary densities of states. Program summaryProgram title: dmft Catalogue identifier: AEIL_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIL_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: ALPS LIBRARY LICENSE version 1.1 No. of lines in distributed program, including test data, etc.: 899 806 No. of bytes in distributed program, including test data, etc.: 32 153 916 Distribution format: tar.gz Programming language: C++ Operating system: The ALPS libraries have been tested on the following platforms and compilers: Linux with GNU Compiler Collection (g++ version 3.1 and higher), and Intel C++ Compiler (icc version 7.0 and higher) MacOS X with GNU Compiler (g++ Apple-version 3.1, 3.3 and 4.0) IBM AIX with Visual Age C++ (xlC version 6.0) and GNU (g++ version 3.1 and higher) compilers Compaq Tru64 UNIX with Compq C++ Compiler (cxx) SGI IRIX with MIPSpro C++ Compiler (CC) HP-UX with HP C++ Compiler (aCC) Windows with Cygwin or coLinux platforms and GNU Compiler Collection (g++ version 3.1 and higher) RAM: 10 MB-1 GB Classification: 7.3 External routines: ALPS [1], BLAS/LAPACK, HDF5 Nature of problem: (See [2].) Quantum impurity models describe an atom or molecule embedded in a host material with which it can exchange electrons. They are basic to nanoscience as

Event-chain Monte Carlo algorithms for three- and many-particle interactions

NASA Astrophysics Data System (ADS)

Harland, J.; Michel, M.; Kampmann, T. A.; Kierfeld, J.

2017-02-01

We generalize the rejection-free event-chain Monte Carlo algorithm from many-particle systems with pairwise interactions to systems with arbitrary three- or many-particle interactions. We introduce generalized lifting probabilities between particles and obtain a general set of equations for lifting probabilities, the solution of which guarantees maximal global balance. We validate the resulting three-particle event-chain Monte Carlo algorithms on three different systems by comparison with conventional local Monte Carlo simulations: i) a test system of three particles with a three-particle interaction that depends on the enclosed triangle area; ii) a hard-needle system in two dimensions, where needle interactions constitute three-particle interactions of the needle end points; iii) a semiflexible polymer chain with a bending energy, which constitutes a three-particle interaction of neighboring chain beads. The examples demonstrate that the generalization to many-particle interactions broadens the applicability of event-chain algorithms considerably.

A Lattice Kinetic Monte Carlo Solver for First-Principles Microkinetic Trend Studies

DOE PAGES

Hoffmann, Max J.; Bligaard, Thomas

2018-01-22

Here, mean-field microkinetic models in combination with Brønsted–Evans–Polanyi like scaling relations have proven highly successful in identifying catalyst materials with good or promising reactivity and selectivity. Analysis of the microkinetic model by means of lattice kinetic Monte Carlo promises a faithful description of a range of atomistic features involving short-range ordering of species in the vicinity of an active site. In this paper, we use the “fruit fly” example reaction of CO oxidation on fcc(111) transition and coinage metals to motivate and develop a lattice kinetic Monte Carlo solver suitable for the numerically challenging case of vastly disparate rate constants.more » As a result, we show that for the case of infinitely fast diffusion and absence of adsorbate-adsorbate interaction it is, in fact, possible to match the prediction of the mean-field-theory method and the lattice kinetic Monte Carlo method. As a corollary, we conclude that lattice kinetic Monte Carlo simulations of surface chemical reactions are most likely to provide additional insight over mean-field simulations if diffusion limitations or adsorbate–adsorbate interactions have a significant influence on the mixing of the adsorbates.« less

A Lattice Kinetic Monte Carlo Solver for First-Principles Microkinetic Trend Studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffmann, Max J.; Bligaard, Thomas

Here, mean-field microkinetic models in combination with Brønsted–Evans–Polanyi like scaling relations have proven highly successful in identifying catalyst materials with good or promising reactivity and selectivity. Analysis of the microkinetic model by means of lattice kinetic Monte Carlo promises a faithful description of a range of atomistic features involving short-range ordering of species in the vicinity of an active site. In this paper, we use the “fruit fly” example reaction of CO oxidation on fcc(111) transition and coinage metals to motivate and develop a lattice kinetic Monte Carlo solver suitable for the numerically challenging case of vastly disparate rate constants.more » As a result, we show that for the case of infinitely fast diffusion and absence of adsorbate-adsorbate interaction it is, in fact, possible to match the prediction of the mean-field-theory method and the lattice kinetic Monte Carlo method. As a corollary, we conclude that lattice kinetic Monte Carlo simulations of surface chemical reactions are most likely to provide additional insight over mean-field simulations if diffusion limitations or adsorbate–adsorbate interactions have a significant influence on the mixing of the adsorbates.« less

Mosaicing of airborne LiDAR bathymetry strips based on Monte Carlo matching

NASA Astrophysics Data System (ADS)

Yang, Fanlin; Su, Dianpeng; Zhang, Kai; Ma, Yue; Wang, Mingwei; Yang, Anxiu

2017-09-01

This study proposes a new methodology for mosaicing airborne light detection and ranging (LiDAR) bathymetry (ALB) data based on Monte Carlo matching. Various errors occur in ALB data due to imperfect system integration and other interference factors. To account for these errors, a Monte Carlo matching algorithm based on a nonlinear least-squares adjustment model is proposed. First, the raw data of strip overlap areas were filtered according to their relative drift of depths. Second, a Monte Carlo model and nonlinear least-squares adjustment model were combined to obtain seven transformation parameters. Then, the multibeam bathymetric data were used to correct the initial strip during strip mosaicing. Finally, to evaluate the proposed method, the experimental results were compared with the results of the Iterative Closest Points (ICP) and three-dimensional Normal Distributions Transform (3D-NDT) algorithms. The results demonstrate that the algorithm proposed in this study is more robust and effective. When the quality of the raw data is poor, the Monte Carlo matching algorithm can still achieve centimeter-level accuracy for overlapping areas, which meets the accuracy of bathymetry required by IHO Standards for Hydrographic Surveys Special Publication No.44.

Finite element model updating using the shadow hybrid Monte Carlo technique

NASA Astrophysics Data System (ADS)

Boulkaibet, I.; Mthembu, L.; Marwala, T.; Friswell, M. I.; Adhikari, S.

2015-02-01

Recent research in the field of finite element model updating (FEM) advocates the adoption of Bayesian analysis techniques to dealing with the uncertainties associated with these models. However, Bayesian formulations require the evaluation of the Posterior Distribution Function which may not be available in analytical form. This is the case in FEM updating. In such cases sampling methods can provide good approximations of the Posterior distribution when implemented in the Bayesian context. Markov Chain Monte Carlo (MCMC) algorithms are the most popular sampling tools used to sample probability distributions. However, the efficiency of these algorithms is affected by the complexity of the systems (the size of the parameter space). The Hybrid Monte Carlo (HMC) offers a very important MCMC approach to dealing with higher-dimensional complex problems. The HMC uses the molecular dynamics (MD) steps as the global Monte Carlo (MC) moves to reach areas of high probability where the gradient of the log-density of the Posterior acts as a guide during the search process. However, the acceptance rate of HMC is sensitive to the system size as well as the time step used to evaluate the MD trajectory. To overcome this limitation we propose the use of the Shadow Hybrid Monte Carlo (SHMC) algorithm. The SHMC algorithm is a modified version of the Hybrid Monte Carlo (HMC) and designed to improve sampling for large-system sizes and time steps. This is done by sampling from a modified Hamiltonian function instead of the normal Hamiltonian function. In this paper, the efficiency and accuracy of the SHMC method is tested on the updating of two real structures; an unsymmetrical H-shaped beam structure and a GARTEUR SM-AG19 structure and is compared to the application of the HMC algorithm on the same structures.

A novel Kinetic Monte Carlo algorithm for Non-Equilibrium Simulations

NASA Astrophysics Data System (ADS)

Jha, Prateek; Kuzovkov, Vladimir; Grzybowski, Bartosz; Olvera de La Cruz, Monica

2012-02-01

We have developed an off-lattice kinetic Monte Carlo simulation scheme for reaction-diffusion problems in soft matter systems. The definition of transition probabilities in the Monte Carlo scheme are taken identical to the transition rates in a renormalized master equation of the diffusion process and match that of the Glauber dynamics of Ising model. Our scheme provides several advantages over the Brownian dynamics technique for non-equilibrium simulations. Since particle displacements are accepted/rejected in a Monte Carlo fashion as opposed to moving particles following a stochastic equation of motion, nonphysical movements (e.g., violation of a hard core assumption) are not possible (these moves have zero acceptance). Further, the absence of a stochastic ``noise'' term resolves the computational difficulties associated with generating statistically independent trajectories with definitive mean properties. Finally, since the timestep is independent of the magnitude of the interaction forces, much longer time-steps can be employed than Brownian dynamics. We discuss the applications of this scheme for dynamic self-assembly of photo-switchable nanoparticles and dynamical problems in polymeric systems.

ME(SSY)**2: Monte Carlo Code for Star Cluster Simulations

NASA Astrophysics Data System (ADS)

Freitag, Marc Dewi

2013-02-01

ME(SSY)**2 stands for “Monte-carlo Experiments with Spherically SYmmetric Stellar SYstems." This code simulates the long term evolution of spherical clusters of stars; it was devised specifically to treat dense galactic nuclei. It is based on the pioneering Monte Carlo scheme proposed by Hénon in the 70's and includes all relevant physical ingredients (2-body relaxation, stellar mass spectrum, collisions, tidal disruption, ldots). It is basically a Monte Carlo resolution of the Fokker-Planck equation. It can cope with any stellar mass spectrum or velocity distribution. Being a particle-based method, it also allows one to take stellar collisions into account in a very realistic way. This unique code, featuring most important physical processes, allows million particle simulations, spanning a Hubble time, in a few CPU days on standard personal computers and provides a wealth of data only rivalized by N-body simulations. The current version of the software requires the use of routines from the "Numerical Recipes in Fortran 77" (http://www.nrbook.com/a/bookfpdf.php).

Chemical accuracy from quantum Monte Carlo for the benzene dimer.

PubMed

Azadi, Sam; Cohen, R E

2015-09-14

We report an accurate study of interactions between benzene molecules using variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) methods. We compare these results with density functional theory using different van der Waals functionals. In our quantum Monte Carlo (QMC) calculations, we use accurate correlated trial wave functions including three-body Jastrow factors and backflow transformations. We consider two benzene molecules in the parallel displaced geometry, and find that by highly optimizing the wave function and introducing more dynamical correlation into the wave function, we compute the weak chemical binding energy between aromatic rings accurately. We find optimal VMC and DMC binding energies of -2.3(4) and -2.7(3) kcal/mol, respectively. The best estimate of the coupled-cluster theory through perturbative triplets/complete basis set limit is -2.65(2) kcal/mol [Miliordos et al., J. Phys. Chem. A 118, 7568 (2014)]. Our results indicate that QMC methods give chemical accuracy for weakly bound van der Waals molecular interactions, comparable to results from the best quantum chemistry methods.

Performance of quantum Monte Carlo for calculating molecular bond lengths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleland, Deidre M., E-mail: deidre.cleland@csiro.au; Per, Manolo C., E-mail: manolo.per@csiro.au

2016-03-28

This work investigates the accuracy of real-space quantum Monte Carlo (QMC) methods for calculating molecular geometries. We present the equilibrium bond lengths of a test set of 30 diatomic molecules calculated using variational Monte Carlo (VMC) and diffusion Monte Carlo (DMC) methods. The effect of different trial wavefunctions is investigated using single determinants constructed from Hartree-Fock (HF) and Density Functional Theory (DFT) orbitals with LDA, PBE, and B3LYP functionals, as well as small multi-configurational self-consistent field (MCSCF) multi-determinant expansions. When compared to experimental geometries, all DMC methods exhibit smaller mean-absolute deviations (MADs) than those given by HF, DFT, and MCSCF.more » The most accurate MAD of 3 ± 2 × 10{sup −3} Å is achieved using DMC with a small multi-determinant expansion. However, the more computationally efficient multi-determinant VMC method has a similar MAD of only 4.0 ± 0.9 × 10{sup −3} Å, suggesting that QMC forces calculated from the relatively simple VMC algorithm may often be sufficient for accurate molecular geometries.« less

Influence of lumbar spine extension on vertical jump height during maximal squat jumping.

PubMed

Blache, Yoann; Monteil, Karine

2014-01-01

The purpose of this study was to determine the influence of lumbar spine extension and erector spinae muscle activation on vertical jump height during maximal squat jumping. Eight male athletes performed maximal squat jumps. Electromyograms of the erector spinae were recorded during these jumps. A simulation model of the musculoskeletal system was used to simulate maximal squat jumping with and without spine extension. The effect on vertical jump height of changing erector spinae strength was also tested through the simulated jumps. Concerning the participant jumps, the kinematics indicated a spine extension and erector spinae activation. Concerning the simulated jumps, vertical jump height was about 5.4 cm lower during squat jump without trunk extension compared to squat jump. These results were explained by greater total muscle work during squat jump, more especially by the erector spinae work (+119.5 J). The erector spinae may contribute to spine extension during maximal squat jumping. The simulated jumps confirmed this hypothesis showing that vertical jumping was decreased if this muscle was not taken into consideration in the model. Therefore it is concluded that the erector spinae should be considered as a trunk extensor, which enables to enhance total muscle work and consequently vertical jump height.

Predominant bacteria and patterns of antibiotic susceptibility in urinary tract infection in children with spina bifida.

PubMed

Ortiz, Tara K; Velazquez, Nermarie; Ding, Laura; Routh, Jonathan C; Wiener, John S; Seed, Patrick C; Ross, Sherry S

2018-04-20

Urinary tract infection is more common in children with spina bifida (SB) than neurologically intact children, and Escherichiacoli is the most common urinary pathogen in the general pediatric population. Less is known of the pathogens responsible for urinary tract infections (UTI) in the pediatric SB population or their evolving antimicrobial resistance patterns. The goal of this study is to determine the epidemiology and antimicrobial resistance patterns of SB-associated urinary pathogens. Between January 1996 and August 2013, 231 patients aged 1 month to 18 years were identified with a diagnosis of SB-NB and at least one symptomatic urinary tract infection (UTI) event (Table). Two-hundred and thirty-one normally voiding children with a single symptomatic UTI were age-matched based on age at diagnosis of UTI at a 1:1 ratio. Chi-square tests and Generalized Estimating Equation analysis, controlling for clinicopathological factors, were performed to compare rates of pathogen-associations with UTI between groups and likelihood of UTI with multi-drug resistant (MDR) organisms. Children in the SB-NB group had a higher rate of non-E. coli UTI compared with controls (64% vs. 41%, p < 0.01), particularly associated with Klebsiella species the SB-NB group had an overall higher infection rate with MDR organisms (21% vs. 10%, p < 0.01) and E. coli isolates, with a trend towards increased rates of antibiotic resistance to aminoglycosides, fluoroquinolones, cephalosporins, extended spectrum β-lactams, and TMP-SMZ. Additionally, patients in the SB-NB group had a 10-fold increase of urosepsis with 57% of events caused by MDR organisms. Children with SB-NB are more likely to have non-E. coli UTI, UTIs with MDR organisms, and urosepsis than the general pediatric population. Published by Elsevier Ltd.

Monte Carlo simulations within avalanche rescue

NASA Astrophysics Data System (ADS)

Reiweger, Ingrid; Genswein, Manuel; Schweizer, Jürg

2016-04-01

Refining concepts for avalanche rescue involves calculating suitable settings for rescue strategies such as an adequate probing depth for probe line searches or an optimal time for performing resuscitation for a recovered avalanche victim in case of additional burials. In the latter case, treatment decisions have to be made in the context of triage. However, given the low number of incidents it is rarely possible to derive quantitative criteria based on historical statistics in the context of evidence-based medicine. For these rare, but complex rescue scenarios, most of the associated concepts, theories, and processes involve a number of unknown "random" parameters which have to be estimated in order to calculate anything quantitatively. An obvious approach for incorporating a number of random variables and their distributions into a calculation is to perform a Monte Carlo (MC) simulation. We here present Monte Carlo simulations for calculating the most suitable probing depth for probe line searches depending on search area and an optimal resuscitation time in case of multiple avalanche burials. The MC approach reveals, e.g., new optimized values for the duration of resuscitation that differ from previous, mainly case-based assumptions.

Validation of the Monte Carlo simulator GATE for indium-111 imaging.

PubMed

Assié, K; Gardin, I; Véra, P; Buvat, I

2005-07-07

Monte Carlo simulations are useful for optimizing and assessing single photon emission computed tomography (SPECT) protocols, especially when aiming at measuring quantitative parameters from SPECT images. Before Monte Carlo simulated data can be trusted, the simulation model must be validated. The purpose of this work was to validate the use of GATE, a new Monte Carlo simulation platform based on GEANT4, for modelling indium-111 SPECT data, the quantification of which is of foremost importance for dosimetric studies. To that end, acquisitions of (111)In line sources in air and in water and of a cylindrical phantom were performed, together with the corresponding simulations. The simulation model included Monte Carlo modelling of the camera collimator and of a back-compartment accounting for photomultiplier tubes and associated electronics. Energy spectra, spatial resolution, sensitivity values, images and count profiles obtained for experimental and simulated data were compared. An excellent agreement was found between experimental and simulated energy spectra. For source-to-collimator distances varying from 0 to 20 cm, simulated and experimental spatial resolution differed by less than 2% in air, while the simulated sensitivity values were within 4% of the experimental values. The simulation of the cylindrical phantom closely reproduced the experimental data. These results suggest that GATE enables accurate simulation of (111)In SPECT acquisitions.

Self-evolving atomistic kinetic Monte Carlo simulations of defects in materials

DOE PAGES

Xu, Haixuan; Beland, Laurent K.; Stoller, Roger E.; ...

2015-01-29

The recent development of on-the-fly atomistic kinetic Monte Carlo methods has led to an increased amount attention on the methods and their corresponding capabilities and applications. In this review, the framework and current status of Self-Evolving Atomistic Kinetic Monte Carlo (SEAKMC) are discussed. SEAKMC particularly focuses on defect interaction and evolution with atomistic details without assuming potential defect migration/interaction mechanisms and energies. The strength and limitation of using an active volume, the key concept introduced in SEAKMC, are discussed. Potential criteria for characterizing an active volume are discussed and the influence of active volume size on saddle point energies ismore » illustrated. A procedure starting with a small active volume followed by larger active volumes was found to possess higher efficiency. Applications of SEAKMC, ranging from point defect diffusion, to complex interstitial cluster evolution, to helium interaction with tungsten surfaces, are summarized. A comparison of SEAKMC with molecular dynamics and conventional object kinetic Monte Carlo is demonstrated. Overall, SEAKMC is found to be complimentary to conventional molecular dynamics, especially when the harmonic approximation of transition state theory is accurate. However it is capable of reaching longer time scales than molecular dynamics and it can be used to systematically increase the accuracy of other methods such as object kinetic Monte Carlo. Furthermore, the challenges and potential development directions are also outlined.« less

Present Status and Extensions of the Monte Carlo Performance Benchmark

NASA Astrophysics Data System (ADS)

Hoogenboom, J. Eduard; Petrovic, Bojan; Martin, William R.

2014-06-01

The NEA Monte Carlo Performance benchmark started in 2011 aiming to monitor over the years the abilities to perform a full-size Monte Carlo reactor core calculation with a detailed power production for each fuel pin with axial distribution. This paper gives an overview of the contributed results thus far. It shows that reaching a statistical accuracy of 1 % for most of the small fuel zones requires about 100 billion neutron histories. The efficiency of parallel execution of Monte Carlo codes on a large number of processor cores shows clear limitations for computer clusters with common type computer nodes. However, using true supercomputers the speedup of parallel calculations is increasing up to large numbers of processor cores. More experience is needed from calculations on true supercomputers using large numbers of processors in order to predict if the requested calculations can be done in a short time. As the specifications of the reactor geometry for this benchmark test are well suited for further investigations of full-core Monte Carlo calculations and a need is felt for testing other issues than its computational performance, proposals are presented for extending the benchmark to a suite of benchmark problems for evaluating fission source convergence for a system with a high dominance ratio, for coupling with thermal-hydraulics calculations to evaluate the use of different temperatures and coolant densities and to study the correctness and effectiveness of burnup calculations. Moreover, other contemporary proposals for a full-core calculation with realistic geometry and material composition will be discussed.

The Influence of Social Adjustment on Normative and Risky Health Behaviors in Emerging Adults With Spina Bifida

PubMed Central

Murray, Caitlin B.; Lennon, Jaclyn M.; Devine, Katie A.; Holmbeck, Grayson N.; Klages, Kimberly; Potthoff, Lauren M.

2015-01-01

Objective To understand the rates of normative and risky health behaviors and the influence of prior and current social adjustment on health risk behaviors in emerging adults with spina bifida (SB). Method These data are part of a larger longitudinal study of youth with SB; at ages 18–19, 50 emerging adults with SB and 60 typically developing (TD) youth participated. Social adjustment was measured at ages 12/13, 14/15, 16/17, and 18/19. Substance use and sexual activity were self-reported by emerging adults. Results The SB group reported similar frequencies (i.e., number of days in the previous month) of cigarette and marijuana use. Fewer individuals with SB reported initiation of both alcohol use (i.e., ever used) and sexual activity (i.e., ever had sex) compared to TD peers. The SB group also reported less frequent alcohol use and fewer sexual partners. Better social adjustment during early adolescence (ages 12/13) predicted more frequent alcohol use and a greater number of sexual partners for all youth. Social adjustment also mediated the effect of group status on health risk behaviors. Conclusions Emerging adults with SB lag behind TD peers in terms of normative initiation of alcohol use and sexual activity. However, this population participates in some risky health behaviors at similar rates compared to their TD peers (e.g., smoking). Youths’ health risk behaviors may be influenced by their level of social adjustment. A challenge for future interventions for this population will be finding methods of improving social functioning without increasing the rate of health risk behavior. PMID:24490647

Monte Carlo calculations of k{sub Q}, the beam quality conversion factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muir, B. R.; Rogers, D. W. O.

2010-11-15

Purpose: To use EGSnrc Monte Carlo simulations to directly calculate beam quality conversion factors, k{sub Q}, for 32 cylindrical ionization chambers over a range of beam qualities and to quantify the effect of systematic uncertainties on Monte Carlo calculations of k{sub Q}. These factors are required to use the TG-51 or TRS-398 clinical dosimetry protocols for calibrating external radiotherapy beams. Methods: Ionization chambers are modeled either from blueprints or manufacturers' user's manuals. The dose-to-air in the chamber is calculated using the EGSnrc user-code egs{sub c}hamber using 11 different tabulated clinical photon spectra for the incident beams. The dose to amore » small volume of water is also calculated in the absence of the chamber at the midpoint of the chamber on its central axis. Using a simple equation, k{sub Q} is calculated from these quantities under the assumption that W/e is constant with energy and compared to TG-51 protocol and measured values. Results: Polynomial fits to the Monte Carlo calculated k{sub Q} factors as a function of beam quality expressed as %dd(10){sub x} and TPR{sub 10}{sup 20} are given for each ionization chamber. Differences are explained between Monte Carlo calculated values and values from the TG-51 protocol or calculated using the computer program used for TG-51 calculations. Systematic uncertainties in calculated k{sub Q} values are analyzed and amount to a maximum of one standard deviation uncertainty of 0.99% if one assumes that photon cross-section uncertainties are uncorrelated and 0.63% if they are assumed correlated. The largest components of the uncertainty are the constancy of W/e and the uncertainty in the cross-section for photons in water. Conclusions: It is now possible to calculate k{sub Q} directly using Monte Carlo simulations. Monte Carlo calculations for most ionization chambers give results which are comparable to TG-51 values. Discrepancies can be explained using individual Monte Carlo

Brain stem/brain stem occipital bone ratio and the four-line view in nuchal translucency images of fetuses with open spina bifida.

PubMed

Iuculano, Ambra; Zoppi, Maria Angelica; Piras, Alessandra; Arras, Maurizio; Monni, Giovanni

2014-09-10

Abstract Objective: Brain stem depth/brain stem occipital bone distance (BS/BSOB ratio) and the four-line view, in images obtained for nuchal translucency (NT) screening in fetuses with open spina bifida (OSB). Methods: Single center, retrospective study based on the assessment of NT screening images of fetuses with OSB. A ratio between the BS depth and the BSOB distance was calculated (BS/BSOB ratio) and the four-line view observed, and the sensitivity for a BS/BSOB ratio superior/equal to 1, and for the lack of detection of the four-line view were calculated. Results: There were 17 cases of prenatal diagnosis OSB. In six cases, the suspicion on OSB was raised during NT screening, in six cases, the diagnosis was made before 20 weeks and in five cases during anomaly scan. The BS/BSOB ratio was superior/equal to 1 in all 17 cases, and three lines, were visualized in 15/17 images of the OSB cases, being the sensitivity 100% (95% CI, 81 to 100%) and 88% (95% CI, 65 to 96%). Conclusion: Assessment of BS/BSOB ratio and four-line view in NT images is feasible detecting affected by OSB with high sensitivity. The presence of associated anomalies or of an enlarged NT enhances the early detection.

Functional Significance of Atypical Cortical Organization in Spina Bifida Myelomeningocele: Relations of Cortical Thickness and Gyrification with IQ and Fine Motor Dexterity

PubMed Central

Treble, Amery; Juranek, Jenifer; Stuebing, Karla K.; Dennis, Maureen; Fletcher, Jack M.

2013-01-01

The cortex in spina bifida myelomeningocele (SBM) is atypically organized, but it is not known how specific features of atypical cortical organization promote or disrupt cognitive and motor function. Relations of deviant cortical thickness and gyrification with IQ and fine motor dexterity were investigated in 64 individuals with SBM and 26 typically developing (TD) individuals, aged 8–28 years. Cortical thickness and 3D local gyrification index (LGI) were quantified from 33 cortical regions per hemisphere using FreeSurfer. Results replicated previous findings, showing regions of higher and lower cortical thickness and LGI in SBM relative to the TD comparison individuals. Cortical thickness and LGI were negatively associated in most cortical regions, though less consistently in the TD group. Whereas cortical thickness and LGI tended to be negatively associated with IQ and fine motor outcomes in regions that were thicker or more gyrified in SBM, associations tended to be positive in regions that were thinner or less gyrified in SBM. The more deviant the levels of cortical thickness and LGI—whether higher or lower relative to the TD group—the more impaired the IQ and fine motor outcomes, suggesting that these cortical atypicalities in SBM are functionally maladaptive, rather than adaptive. PMID:22875857

Modifying the Monte Carlo Quiz to Increase Student Motivation, Participation, and Content Retention

ERIC Educational Resources Information Center

Simonson, Shawn R.

2017-01-01

Fernald developed the Monte Carlo Quiz format to enhance retention, encourage students to prepare for class, read with intention, and organize information in psychology classes. This author modified the Monte Carlo Quiz, combined it with the Minute Paper, and applied it to various courses. Students write quiz questions as part of the Minute Paper…

Data decomposition of Monte Carlo particle transport simulations via tally servers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Romano, Paul K.; Siegel, Andrew R.; Forget, Benoit

An algorithm for decomposing large tally data in Monte Carlo particle transport simulations is developed, analyzed, and implemented in a continuous-energy Monte Carlo code, OpenMC. The algorithm is based on a non-overlapping decomposition of compute nodes into tracking processors and tally servers. The former are used to simulate the movement of particles through the domain while the latter continuously receive and update tally data. A performance model for this approach is developed, suggesting that, for a range of parameters relevant to LWR analysis, the tally server algorithm should perform with minimal overhead on contemporary supercomputers. An implementation of the algorithmmore » in OpenMC is then tested on the Intrepid and Titan supercomputers, supporting the key predictions of the model over a wide range of parameters. We thus conclude that the tally server algorithm is a successful approach to circumventing classical on-node memory constraints en route to unprecedentedly detailed Monte Carlo reactor simulations.« less

Total energy expenditure and body composition of children with developmental disabilities.

PubMed

Polfuss, Michele; Sawin, Kathleen J; Papanek, Paula E; Bandini, Linda; Forseth, Bethany; Moosreiner, Andrea; Zvara, Kimberley; Schoeller, Dale A

2018-07-01

Obesity prevalence is increased in children with developmental disabilities, specifically in children with spina bifida and Down syndrome. Energy expenditure, a critical aspect of weight management, has been extensively studied in the typically developing population, but not adequately studied in children with developmental disabilities. Determine energy expenditure, fat-free mass and body fat percentile and the impact of these findings on recommended caloric intake in children with spina bifida and Down syndrome. This pilot study included 36 children, 18 with spina bifida, 9 with Down syndrome and 9 typically developing children. Half of the children with spina bifida were non-ambulatory. Doubly labeled water was used to measure energy expenditure and body composition. Descriptive statistics described the sample and MANOVA and ANOVA methods were used to evaluate differences between groups. Energy expenditure was significantly less for children with spina bifida who primarily used a wheelchair (p = .001) and children with Down syndrome (p = .041) when compared to children without a disability when adjusted for fat-free mass. However, no significant difference was detected in children with spina bifida who ambulated without assistance (p = .072). Children with spina bifida and Down syndrome have a significantly decreased energy expenditure which directly impacts recommended caloric intake. No significant difference was detected for children with spina bifida who ambulated, although the small sample size of this pilot study may have limited these findings. Validating these results in a larger study is integral to supporting successful weight management of these children. Copyright © 2017 Elsevier Inc. All rights reserved.

CONTINUOUS-ENERGY MONTE CARLO METHODS FOR CALCULATING GENERALIZED RESPONSE SENSITIVITIES USING TSUNAMI-3D

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perfetti, Christopher M; Rearden, Bradley T

2014-01-01

This work introduces a new approach for calculating sensitivity coefficients for generalized neutronic responses to nuclear data uncertainties using continuous-energy Monte Carlo methods. The approach presented in this paper, known as the GEAR-MC method, allows for the calculation of generalized sensitivity coefficients for multiple responses in a single Monte Carlo calculation with no nuclear data perturbations or knowledge of nuclear covariance data. The theory behind the GEAR-MC method is presented here, and proof of principle is demonstrated by using the GEAR-MC method to calculate sensitivity coefficients for responses in several 3D, continuous-energy Monte Carlo applications.

Monte Carlo simulation of energy-dispersive x-ray fluorescence and applications

NASA Astrophysics Data System (ADS)

Li, Fusheng

Four key components with regards to Monte Carlo Library Least Squares (MCLLS) have been developed by the author. These include: a comprehensive and accurate Monte Carlo simulation code - CEARXRF5 with Differential Operators (DO) and coincidence sampling, Detector Response Function (DRF), an integrated Monte Carlo - Library Least-Squares (MCLLS) Graphical User Interface (GUI) visualization System (MCLLSPro) and a new reproducible and flexible benchmark experiment setup. All these developments or upgrades enable the MCLLS approach to be a useful and powerful tool for a tremendous variety of elemental analysis applications. CEARXRF, a comprehensive and accurate Monte Carlo code for simulating the total and individual library spectral responses of all elements, has been recently upgraded to version 5 by the author. The new version has several key improvements: input file format fully compatible with MCNP5, a new efficient general geometry tracking code, versatile source definitions, various variance reduction techniques (e.g. weight window mesh and splitting, stratifying sampling, etc.), a new cross section data storage and accessing method which improves the simulation speed by a factor of four and new cross section data, upgraded differential operators (DO) calculation capability, and also an updated coincidence sampling scheme which including K-L and L-L coincidence X-Rays, while keeping all the capabilities of the previous version. The new Differential Operators method is powerful for measurement sensitivity study and system optimization. For our Monte Carlo EDXRF elemental analysis system, it becomes an important technique for quantifying the matrix effect in near real time when combined with the MCLLS approach. An integrated visualization GUI system has been developed by the author to perform elemental analysis using iterated Library Least-Squares method for various samples when an initial guess is provided. This software was built on the Borland C++ Builder

Frequency-resolved Monte Carlo.

PubMed

López Carreño, Juan Camilo; Del Valle, Elena; Laussy, Fabrice P

2018-05-03

We adapt the Quantum Monte Carlo method to the cascaded formalism of quantum optics, allowing us to simulate the emission of photons of known energy. Statistical processing of the photon clicks thus collected agrees with the theory of frequency-resolved photon correlations, extending the range of applications based on correlations of photons of prescribed energy, in particular those of a photon-counting character. We apply the technique to autocorrelations of photon streams from a two-level system under coherent and incoherent pumping, including the Mollow triplet regime where we demonstrate the direct manifestation of leapfrog processes in producing an increased rate of two-photon emission events.

The dynamics of magma chamber refilling at the Campi Flegrei caldera.

NASA Astrophysics Data System (ADS)

Montagna, Chiara Paola; Vassalli, Melissa; Longo, Antonella; Papale, Paolo; Giudice, Salvatore; Saccorotti, Gilberto

2010-05-01

The volcanologic and petrologic reconstructions of several eruptions during the last tens of thousand years of volcanism at the Campi Flegrei caldera show that in most cases a small, chemically evolved, partially degassed magma chamber was refilled by magma of deeper origin shortly before the eruption. New magma input in a shallow chamber is revealed from a variety of indicators, well described in the literature, that include major-trace element and isotope heterogeneities, and crystal-liquid disequilibria (e.g., Arienzo et al., Bull. Volcanol., 2009). In the case of the 4100 BP Agnano Monte Spina eruption, representing the highest intensity and magnitude event of the last epoch of activity, it has been suggested that the refilling occurred within a few tens of hours from the start of the eruption. Notably, in such a case the two end-member magmas that mixed shortly before eruption onset are not recognized as individual members in the deposits, rather, their composition and characteristics are reconstructed from small scale disequilibria, revealing that a relatively short time was sufficient for efficient mixing of the liquid components. In order to investigate the dynamics of magma chamber refilling and mixing at Campi Flegrei we have applied the GALES code (Longo et al., Geophys. Res. Lett., 2006) in a series of numerical simulations. The initial and boundary conditions have been defined in the frame of two subsequent projects coordinated by INGV and funded by the Italian Civil Protection Department, that gather a large number of experts on Campi Flegrei, and are consistent with the bulk of knowledge on the deep magmatic system. In all cases an initial compositional interface is placed at a certain depth, with non-degassed, buoyant magma placed below. The simulations investigate both the dynamics in a very large, 8 km deep reservoir revealed by seismic tomography (Zollo et al., Geophys. Res. Lett., 2008), and those in shallower and smaller chamber systems

SABRINA - An interactive geometry modeler for MCNP (Monte Carlo Neutron Photon)

DOE Office of Scientific and Technical Information (OSTI.GOV)

West, J.T.; Murphy, J.

SABRINA is an interactive three-dimensional geometry modeler developed to produce complicated models for the Los Alamos Monte Carlo Neutron Photon program MCNP. SABRINA produces line drawings and color-shaded drawings for a wide variety of interactive graphics terminals. It is used as a geometry preprocessor in model development and as a Monte Carlo particle-track postprocessor in the visualization of complicated particle transport problem. SABRINA is written in Fortran 77 and is based on the Los Alamos Common Graphics System, CGS. 5 refs., 2 figs.

Metis: A Pure Metropolis Markov Chain Monte Carlo Bayesian Inference Library

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bates, Cameron Russell; Mckigney, Edward Allen

The use of Bayesian inference in data analysis has become the standard for large scienti c experiments [1, 2]. The Monte Carlo Codes Group(XCP-3) at Los Alamos has developed a simple set of algorithms currently implemented in C++ and Python to easily perform at-prior Markov Chain Monte Carlo Bayesian inference with pure Metropolis sampling. These implementations are designed to be user friendly and extensible for customization based on speci c application requirements. This document describes the algorithmic choices made and presents two use cases.

APPLICATION OF BAYESIAN MONTE CARLO ANALYSIS TO A LAGRANGIAN PHOTOCHEMICAL AIR QUALITY MODEL. (R824792)

EPA Science Inventory

Uncertainties in ozone concentrations predicted with a Lagrangian photochemical air quality model have been estimated using Bayesian Monte Carlo (BMC) analysis. Bayesian Monte Carlo analysis provides a means of combining subjective "prior" uncertainty estimates developed ...

Optimization of the Monte Carlo code for modeling of photon migration in tissue.

PubMed

Zołek, Norbert S; Liebert, Adam; Maniewski, Roman

2006-10-01

The Monte Carlo method is frequently used to simulate light transport in turbid media because of its simplicity and flexibility, allowing to analyze complicated geometrical structures. Monte Carlo simulations are, however, time consuming because of the necessity to track the paths of individual photons. The time consuming computation is mainly associated with the calculation of the logarithmic and trigonometric functions as well as the generation of pseudo-random numbers. In this paper, the Monte Carlo algorithm was developed and optimized, by approximation of the logarithmic and trigonometric functions. The approximations were based on polynomial and rational functions, and the errors of these approximations are less than 1% of the values of the original functions. The proposed algorithm was verified by simulations of the time-resolved reflectance at several source-detector separations. The results of the calculation using the approximated algorithm were compared with those of the Monte Carlo simulations obtained with an exact computation of the logarithm and trigonometric functions as well as with the solution of the diffusion equation. The errors of the moments of the simulated distributions of times of flight of photons (total number of photons, mean time of flight and variance) are less than 2% for a range of optical properties, typical of living tissues. The proposed approximated algorithm allows to speed up the Monte Carlo simulations by a factor of 4. The developed code can be used on parallel machines, allowing for further acceleration.

Monte Carlo Modeling of the Initial Radiation Emitted by a Nuclear Device in the National Capital Region

DTIC Science & Technology

2013-07-01

also simulated in the models. Data was derived from calculations using the three-dimensional Monte Carlo radiation transport code MCNP (Monte Carlo N...32  B.  MCNP PHYSICS OPTIONS ......................................................................................... 33  C.  HAZUS...input deck’) for the MCNP , Monte Carlo N-Particle, radiation transport code. MCNP is a general-purpose code designed to simulate neutron, photon

Quantum Monte Carlo Endstation for Petascale Computing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lubos Mitas

2011-01-26

NCSU research group has been focused on accomplising the key goals of this initiative: establishing new generation of quantum Monte Carlo (QMC) computational tools as a part of Endstation petaflop initiative for use at the DOE ORNL computational facilities and for use by computational electronic structure community at large; carrying out high accuracy quantum Monte Carlo demonstration projects in application of these tools to the forefront electronic structure problems in molecular and solid systems; expanding the impact of QMC methods and approaches; explaining and enhancing the impact of these advanced computational approaches. In particular, we have developed quantum Monte Carlomore » code (QWalk, www.qwalk.org) which was significantly expanded and optimized using funds from this support and at present became an actively used tool in the petascale regime by ORNL researchers and beyond. These developments have been built upon efforts undertaken by the PI's group and collaborators over the period of the last decade. The code was optimized and tested extensively on a number of parallel architectures including petaflop ORNL Jaguar machine. We have developed and redesigned a number of code modules such as evaluation of wave functions and orbitals, calculations of pfaffians and introduction of backflow coordinates together with overall organization of the code and random walker distribution over multicore architectures. We have addressed several bottlenecks such as load balancing and verified efficiency and accuracy of the calculations with the other groups of the Endstation team. The QWalk package contains about 50,000 lines of high quality object-oriented C++ and includes also interfaces to data files from other conventional electronic structure codes such as Gamess, Gaussian, Crystal and others. This grant supported PI for one month during summers, a full-time postdoc and partially three graduate students over the period of the grant duration, it has resulted in

Monte Carlo Methods in Materials Science Based on FLUKA and ROOT

NASA Technical Reports Server (NTRS)

Pinsky, Lawrence; Wilson, Thomas; Empl, Anton; Andersen, Victor

2003-01-01

A comprehensive understanding of mitigation measures for space radiation protection necessarily involves the relevant fields of nuclear physics and particle transport modeling. One method of modeling the interaction of radiation traversing matter is Monte Carlo analysis, a subject that has been evolving since the very advent of nuclear reactors and particle accelerators in experimental physics. Countermeasures for radiation protection from neutrons near nuclear reactors, for example, were an early application and Monte Carlo methods were quickly adapted to this general field of investigation. The project discussed here is concerned with taking the latest tools and technology in Monte Carlo analysis and adapting them to space applications such as radiation shielding design for spacecraft, as well as investigating how next-generation Monte Carlos can complement the existing analytical methods currently used by NASA. We have chosen to employ the Monte Carlo program known as FLUKA (A legacy acronym based on the German for FLUctuating KAscade) used to simulate all of the particle transport, and the CERN developed graphical-interface object-oriented analysis software called ROOT. One aspect of space radiation analysis for which the Monte Carlo s are particularly suited is the study of secondary radiation produced as albedoes in the vicinity of the structural geometry involved. This broad goal of simulating space radiation transport through the relevant materials employing the FLUKA code necessarily requires the addition of the capability to simulate all heavy-ion interactions from 10 MeV/A up to the highest conceivable energies. For all energies above 3 GeV/A the Dual Parton Model (DPM) is currently used, although the possible improvement of the DPMJET event generator for energies 3-30 GeV/A is being considered. One of the major tasks still facing us is the provision for heavy ion interactions below 3 GeV/A. The ROOT interface is being developed in conjunction with the

Variational Approach to Monte Carlo Renormalization Group

NASA Astrophysics Data System (ADS)

Wu, Yantao; Car, Roberto

2017-12-01

We present a Monte Carlo method for computing the renormalized coupling constants and the critical exponents within renormalization theory. The scheme, which derives from a variational principle, overcomes critical slowing down, by means of a bias potential that renders the coarse grained variables uncorrelated. The two-dimensional Ising model is used to illustrate the method.

Gray: a ray tracing-based Monte Carlo simulator for PET.

PubMed

Freese, David L; Olcott, Peter D; Buss, Samuel R; Levin, Craig S

2018-05-21

Monte Carlo simulation software plays a critical role in PET system design. Performing complex, repeated Monte Carlo simulations can be computationally prohibitive, as even a single simulation can require a large amount of time and a computing cluster to complete. Here we introduce Gray, a Monte Carlo simulation software for PET systems. Gray exploits ray tracing methods used in the computer graphics community to greatly accelerate simulations of PET systems with complex geometries. We demonstrate the implementation of models for positron range, annihilation acolinearity, photoelectric absorption, Compton scatter, and Rayleigh scatter. For validation, we simulate the GATE PET benchmark, and compare energy, distribution of hits, coincidences, and run time. We show a [Formula: see text] speedup using Gray, compared to GATE for the same simulation, while demonstrating nearly identical results. We additionally simulate the Siemens Biograph mCT system with both the NEMA NU-2 scatter phantom and sensitivity phantom. We estimate the total sensitivity within [Formula: see text]% when accounting for differences in peak NECR. We also estimate the peak NECR to be [Formula: see text] kcps, or within [Formula: see text]% of published experimental data. The activity concentration of the peak is also estimated within 1.3%.

A New Approach to Monte Carlo Simulations in Statistical Physics

NASA Astrophysics Data System (ADS)

Landau, David P.

2002-08-01

Monte Carlo simulations [1] have become a powerful tool for the study of diverse problems in statistical/condensed matter physics. Standard methods sample the probability distribution for the states of the system, most often in the canonical ensemble, and over the past several decades enormous improvements have been made in performance. Nonetheless, difficulties arise near phase transitions-due to critical slowing down near 2nd order transitions and to metastability near 1st order transitions, and these complications limit the applicability of the method. We shall describe a new Monte Carlo approach [2] that uses a random walk in energy space to determine the density of states directly. Once the density of states is known, all thermodynamic properties can be calculated. This approach can be extended to multi-dimensional parameter spaces and should be effective for systems with complex energy landscapes, e.g., spin glasses, protein folding models, etc. Generalizations should produce a broadly applicable optimization tool. 1. A Guide to Monte Carlo Simulations in Statistical Physics, D. P. Landau and K. Binder (Cambridge U. Press, Cambridge, 2000). 2. Fugao Wang and D. P. Landau, Phys. Rev. Lett. 86, 2050 (2001); Phys. Rev. E64, 056101-1 (2001).

Gray: a ray tracing-based Monte Carlo simulator for PET

NASA Astrophysics Data System (ADS)

Freese, David L.; Olcott, Peter D.; Buss, Samuel R.; Levin, Craig S.

2018-05-01

Monte Carlo simulation software plays a critical role in PET system design. Performing complex, repeated Monte Carlo simulations can be computationally prohibitive, as even a single simulation can require a large amount of time and a computing cluster to complete. Here we introduce Gray, a Monte Carlo simulation software for PET systems. Gray exploits ray tracing methods used in the computer graphics community to greatly accelerate simulations of PET systems with complex geometries. We demonstrate the implementation of models for positron range, annihilation acolinearity, photoelectric absorption, Compton scatter, and Rayleigh scatter. For validation, we simulate the GATE PET benchmark, and compare energy, distribution of hits, coincidences, and run time. We show a speedup using Gray, compared to GATE for the same simulation, while demonstrating nearly identical results. We additionally simulate the Siemens Biograph mCT system with both the NEMA NU-2 scatter phantom and sensitivity phantom. We estimate the total sensitivity within % when accounting for differences in peak NECR. We also estimate the peak NECR to be kcps, or within % of published experimental data. The activity concentration of the peak is also estimated within 1.3%.

Quantum Monte Carlo methods for nuclear physics

DOE PAGES

Carlson, Joseph A.; Gandolfi, Stefano; Pederiva, Francesco; ...

2014-10-19

Quantum Monte Carlo methods have proved very valuable to study the structure and reactions of light nuclei and nucleonic matter starting from realistic nuclear interactions and currents. These ab-initio calculations reproduce many low-lying states, moments and transitions in light nuclei, and simultaneously predict many properties of light nuclei and neutron matter over a rather wide range of energy and momenta. We review the nuclear interactions and currents, and describe the continuum Quantum Monte Carlo methods used in nuclear physics. These methods are similar to those used in condensed matter and electronic structure but naturally include spin-isospin, tensor, spin-orbit, and three-bodymore » interactions. We present a variety of results including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. We also describe low-energy scattering techniques, studies of the electroweak response of nuclei relevant in electron and neutrino scattering, and the properties of dense nucleonic matter as found in neutron stars. A coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.« less

Gutzwiller Monte Carlo approach for a critical dissipative spin model

NASA Astrophysics Data System (ADS)

Casteels, Wim; Wilson, Ryan M.; Wouters, Michiel

2018-06-01

We use the Gutzwiller Monte Carlo approach to simulate the dissipative X Y Z model in the vicinity of a dissipative phase transition. This approach captures classical spatial correlations together with the full on-site quantum behavior while neglecting nonlocal quantum effects. By considering finite two-dimensional lattices of various sizes, we identify a ferromagnetic and two paramagnetic phases, in agreement with earlier studies. The greatly reduced numerical complexity of the Gutzwiller Monte Carlo approach facilitates efficient simulation of relatively large lattice sizes. The inclusion of the spatial correlations allows to capture parts of the phase diagram that are completely missed by the widely applied Gutzwiller decoupling of the density matrix.

A Variational Monte Carlo Approach to Atomic Structure

ERIC Educational Resources Information Center

Davis, Stephen L.

2007-01-01

The practicality and usefulness of variational Monte Carlo calculations to atomic structure are demonstrated. It is found to succeed in quantitatively illustrating electron shielding, effective nuclear charge, l-dependence of the orbital energies, and singlet-tripetenergy splitting and ionization energy trends in atomic structure theory.

Does standard Monte Carlo give justice to instantons?

NASA Astrophysics Data System (ADS)

Fucito, F.; Solomon, S.

1984-01-01

The results of the standard local Monte Carlo are changed by offering instantons as candidates in the Metropolis procedure. We also define an O(3) topological charge with no contribution from planar dislocations. The RG behavior is still not recovered. Bantrell Fellow in Theoretical Physics.

Molecular Monte Carlo Simulations Using Graphics Processing Units: To Waste Recycle or Not?

PubMed

Kim, Jihan; Rodgers, Jocelyn M; Athènes, Manuel; Smit, Berend

2011-10-11

In the waste recycling Monte Carlo (WRMC) algorithm, (1) multiple trial states may be simultaneously generated and utilized during Monte Carlo moves to improve the statistical accuracy of the simulations, suggesting that such an algorithm may be well posed for implementation in parallel on graphics processing units (GPUs). In this paper, we implement two waste recycling Monte Carlo algorithms in CUDA (Compute Unified Device Architecture) using uniformly distributed random trial states and trial states based on displacement random-walk steps, and we test the methods on a methane-zeolite MFI framework system to evaluate their utility. We discuss the specific implementation details of the waste recycling GPU algorithm and compare the methods to other parallel algorithms optimized for the framework system. We analyze the relationship between the statistical accuracy of our simulations and the CUDA block size to determine the efficient allocation of the GPU hardware resources. We make comparisons between the GPU and the serial CPU Monte Carlo implementations to assess speedup over conventional microprocessors. Finally, we apply our optimized GPU algorithms to the important problem of determining free energy landscapes, in this case for molecular motion through the zeolite LTA.

A Monte Carlo method using octree structure in photon and electron transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ogawa, K.; Maeda, S.

Most of the early Monte Carlo calculations in medical physics were used to calculate absorbed dose distributions, and detector responses and efficiencies. Recently, data acquisition in Single Photon Emission CT (SPECT) has been simulated by a Monte Carlo method to evaluate scatter photons generated in a human body and a collimator. Monte Carlo simulations in SPECT data acquisition are generally based on the transport of photons only because the photons being simulated are low energy, and therefore the bremsstrahlung productions by the electrons generated are negligible. Since the transport calculation of photons without electrons is much simpler than that withmore » electrons, it is possible to accomplish the high-speed simulation in a simple object with one medium. Here, object description is important in performing the photon and/or electron transport using a Monte Carlo method efficiently. The authors propose a new description method using an octree representation of an object. Thus even if the boundaries of each medium are represented accurately, high-speed calculation of photon transport can be accomplished because the number of voxels is much fewer than that of the voxel-based approach which represents an object by a union of the voxels of the same size. This Monte Carlo code using the octree representation of an object first establishes the simulation geometry by reading octree string, which is produced by forming an octree structure from a set of serial sections for the object before the simulation; then it transports photons in the geometry. Using the code, if the user just prepares a set of serial sections for the object in which he or she wants to simulate photon trajectories, he or she can perform the simulation automatically using the suboptimal geometry simplified by the octree representation without forming the optimal geometry by handwriting.« less

Magellan radar image of Danu Montes in Lakshmi Region of Venus

NASA Technical Reports Server (NTRS)

1990-01-01

This Magellan radar mosaic image is of part of the Danu Montes in the Lakshmi Region of Venus. The area in the image is located at 329.6 degrees east longitude and 58.75 degrees north latitude. This image shows an area 40 kilometers (km) (19.6 miles) wide and 60 km (39.2 miles) long. Danu Montes is a mountain belt located at the southern edge of the Ishtar Terra highland region. It rises one to three kilometers above a flat plain to the north known as Lakshmi Planum. On the basis of Pioneer Venus, Arecibo and Venera data, Danu Montes and the other mountain belts surrounding Lakshmi Planum have been interpreted to be orogenic belts marking the focus of compressional deformation, much like the Appalachian and Andes ranges on Earth. In the upper right part of this image, relatively bright, smooth-textured plains of Lakshmi Planum are seen to embay the heavily deformed mountain range to the south. In the mountain range south of these plains the geology is dominated by abundant faults at mu

Using hybrid implicit Monte Carlo diffusion to simulate gray radiation hydrodynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleveland, Mathew A., E-mail: cleveland7@llnl.gov; Gentile, Nick

This work describes how to couple a hybrid Implicit Monte Carlo Diffusion (HIMCD) method with a Lagrangian hydrodynamics code to evaluate the coupled radiation hydrodynamics equations. This HIMCD method dynamically applies Implicit Monte Carlo Diffusion (IMD) [1] to regions of a problem that are opaque and diffusive while applying standard Implicit Monte Carlo (IMC) [2] to regions where the diffusion approximation is invalid. We show that this method significantly improves the computational efficiency as compared to a standard IMC/Hydrodynamics solver, when optically thick diffusive material is present, while maintaining accuracy. Two test cases are used to demonstrate the accuracy andmore » performance of HIMCD as compared to IMC and IMD. The first is the Lowrie semi-analytic diffusive shock [3]. The second is a simple test case where the source radiation streams through optically thin material and heats a thick diffusive region of material causing it to rapidly expand. We found that HIMCD proves to be accurate, robust, and computationally efficient for these test problems.« less

Quantum Monte Carlo Simulation of Frustrated Kondo Lattice Models

NASA Astrophysics Data System (ADS)

Sato, Toshihiro; Assaad, Fakher F.; Grover, Tarun

2018-03-01

The absence of the negative sign problem in quantum Monte Carlo simulations of spin and fermion systems has different origins. World-line based algorithms for spins require positivity of matrix elements whereas auxiliary field approaches for fermions depend on symmetries such as particle-hole symmetry. For negative-sign-free spin and fermionic systems, we show that one can formulate a negative-sign-free auxiliary field quantum Monte Carlo algorithm that allows Kondo coupling of fermions with the spins. Using this general approach, we study a half-filled Kondo lattice model on the honeycomb lattice with geometric frustration. In addition to the conventional Kondo insulator and antiferromagnetically ordered phases, we find a partial Kondo screened state where spins are selectively screened so as to alleviate frustration, and the lattice rotation symmetry is broken nematically.

Large-cell Monte Carlo renormalization of irreversible growth processes

NASA Technical Reports Server (NTRS)

Nakanishi, H.; Family, F.

1985-01-01

Monte Carlo sampling is applied to a recently formulated direct-cell renormalization method for irreversible, disorderly growth processes. Large-cell Monte Carlo renormalization is carried out for various nonequilibrium problems based on the formulation dealing with relative probabilities. Specifically, the method is demonstrated by application to the 'true' self-avoiding walk and the Eden model of growing animals for d = 2, 3, and 4 and to the invasion percolation problem for d = 2 and 3. The results are asymptotically in agreement with expectations; however, unexpected complications arise, suggesting the possibility of crossovers, and in any case, demonstrating the danger of using small cells alone, because of the very slow convergence as the cell size b is extrapolated to infinity. The difficulty of applying the present method to the diffusion-limited-aggregation model, is commented on.

Frost in Charitum Montes

NASA Technical Reports Server (NTRS)

2003-01-01

MGS MOC Release No. MOC2-387, 10 June 2003

This is a Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) wide angle view of the Charitum Montes, south of Argyre Planitia, in early June 2003. The seasonal south polar frost cap, composed of carbon dioxide, has been retreating southward through this area since spring began a month ago. The bright features toward the bottom of this picture are surfaces covered by frost. The picture is located near 57oS, 43oW. North is at the top, south is at the bottom. Sunlight illuminates the scene from the upper left. The area shown is about 217 km (135 miles) wide.

Plasticity of Interhemispheric Temporal Lobe White Matter Pathways Due to Early Disruption of Corpus Callosum Development in Spina Bifida

PubMed Central

Juranek, Jenifer; Romanowska-Pawliczek, Anna; Hannay, H. Julia; Cirino, Paul T.; Dennis, Maureen; Kramer, Larry A.; Fletcher, Jack M.

2016-01-01

Abstract Spina bifida myelomeningocele (SBM) is commonly associated with anomalous development of the corpus callosum (CC) because of congenital partial hypogenesis and hydrocephalus-related hypoplasia. It represents a model disorder to examine the effects of early disruption of CC neurodevelopment and the plasticity of interhemispheric white matter connections. Diffusion tensor imaging was acquired on 76 individuals with SBM and 27 typically developing individuals, aged 8–36 years. Probabilistic tractography was used to isolate the interhemispheric connections between the posterior superior temporal lobes, which typically traverse the posterior third of the CC. Early disruption of CC development resulted in restructuring of interhemispheric connections through alternate commissures, particularly the anterior commissure (AC). These rerouted fibers were present in people with SBM and both CC hypoplasia and hypogenesis. In addition, microstructural integrity was reduced in the interhemispheric temporal tract in people with SBM, indexed by lower fractional anisotropy, axial diffusivity, and higher radial diffusivity. Interhemispheric temporal tract volume was positively correlated with total volume of the CC, such that more severe underdevelopment of the CC was associated with fewer connections between the posterior temporal lobes. Therefore, both the macrostructure and microstructure of this interhemispheric tract were reduced, presumably as a result of more extensive CC malformation. The current findings suggest that early disruption in CC development reroutes interhemispheric temporal fibers through both the AC and more anterior sections of the CC in support of persistent hypotheses that the AC may serve a compensatory function in atypical CC development. PMID:26798959

Multilevel and quasi-Monte Carlo methods for uncertainty quantification in particle travel times through random heterogeneous porous media

NASA Astrophysics Data System (ADS)

Crevillén-García, D.; Power, H.

2017-08-01

In this study, we apply four Monte Carlo simulation methods, namely, Monte Carlo, quasi-Monte Carlo, multilevel Monte Carlo and multilevel quasi-Monte Carlo to the problem of uncertainty quantification in the estimation of the average travel time during the transport of particles through random heterogeneous porous media. We apply the four methodologies to a model problem where the only input parameter, the hydraulic conductivity, is modelled as a log-Gaussian random field by using direct Karhunen-Loéve decompositions. The random terms in such expansions represent the coefficients in the equations. Numerical calculations demonstrating the effectiveness of each of the methods are presented. A comparison of the computational cost incurred by each of the methods for three different tolerances is provided. The accuracy of the approaches is quantified via the mean square error.

Multilevel and quasi-Monte Carlo methods for uncertainty quantification in particle travel times through random heterogeneous porous media.

PubMed

Crevillén-García, D; Power, H

2017-08-01

In this study, we apply four Monte Carlo simulation methods, namely, Monte Carlo, quasi-Monte Carlo, multilevel Monte Carlo and multilevel quasi-Monte Carlo to the problem of uncertainty quantification in the estimation of the average travel time during the transport of particles through random heterogeneous porous media. We apply the four methodologies to a model problem where the only input parameter, the hydraulic conductivity, is modelled as a log-Gaussian random field by using direct Karhunen-Loéve decompositions. The random terms in such expansions represent the coefficients in the equations. Numerical calculations demonstrating the effectiveness of each of the methods are presented. A comparison of the computational cost incurred by each of the methods for three different tolerances is provided. The accuracy of the approaches is quantified via the mean square error.

Comparison of space radiation calculations for deterministic and Monte Carlo transport codes

NASA Astrophysics Data System (ADS)

Lin, Zi-Wei; Adams, James; Barghouty, Abdulnasser; Randeniya, Sharmalee; Tripathi, Ram; Watts, John; Yepes, Pablo

For space radiation protection of astronauts or electronic equipments, it is necessary to develop and use accurate radiation transport codes. Radiation transport codes include deterministic codes, such as HZETRN from NASA and UPROP from the Naval Research Laboratory, and Monte Carlo codes such as FLUKA, the Geant4 toolkit and HETC-HEDS. The deterministic codes and Monte Carlo codes complement each other in that deterministic codes are very fast while Monte Carlo codes are more elaborate. Therefore it is important to investigate how well the results of deterministic codes compare with those of Monte Carlo transport codes and where they differ. In this study we evaluate these different codes in their space radiation applications by comparing their output results in the same given space radiation environments, shielding geometry and material. Typical space radiation environments such as the 1977 solar minimum galactic cosmic ray environment are used as the well-defined input, and simple geometries made of aluminum, water and/or polyethylene are used to represent the shielding material. We then compare various outputs of these codes, such as the dose-depth curves and the flux spectra of different fragments and other secondary particles. These comparisons enable us to learn more about the main differences between these space radiation transport codes. At the same time, they help us to learn the qualitative and quantitative features that these transport codes have in common.

Monte Carlo Simulation of Microscopic Stock Market Models

NASA Astrophysics Data System (ADS)

Stauffer, Dietrich

Computer simulations with random numbers, that is, Monte Carlo methods, have been considerably applied in recent years to model the fluctuations of stock market or currency exchange rates. Here we concentrate on the percolation model of Cont and Bouchaud, to simulate, not to predict, the market behavior.

Copy number variation analysis implicates the cell polarity gene glypican 5 as a human spina bifida candidate gene

PubMed Central

Bassuk, Alexander G.; Muthuswamy, Lakshmi B.; Boland, Riley; Smith, Tiffany L.; Hulstrand, Alissa M.; Northrup, Hope; Hakeman, Matthew; Dierdorff, Jason M.; Yung, Christina K.; Long, Abby; Brouillette, Rachel B.; Au, Kit Sing; Gurnett, Christina; Houston, Douglas W.; Cornell, Robert A.; Manak, J. Robert

2013-01-01

Neural tube defects (NTDs) are common birth defects of complex etiology. Family and population-based studies have confirmed a genetic component to NTDs. However, despite more than three decades of research, the genes involved in human NTDs remain largely unknown. We tested the hypothesis that rare copy number variants (CNVs), especially de novo germline CNVs, are a significant risk factor for NTDs. We used array-based comparative genomic hybridization (aCGH) to identify rare CNVs in 128 Caucasian and 61 Hispanic patients with non-syndromic lumbar-sacral myelomeningocele. We also performed aCGH analysis on the parents of affected individuals with rare CNVs where parental DNA was available (42 sets). Among the eight de novo CNVs that we identified, three generated copy number changes of entire genes. One large heterozygous deletion removed 27 genes, including PAX3, a known spina bifida-associated gene. A second CNV altered genes (PGPD8, ZC3H6) for which little is known regarding function or expression. A third heterozygous deletion removed GPC5 and part of GPC6, genes encoding glypicans. Glypicans are proteoglycans that modulate the activity of morphogens such as Sonic Hedgehog (SHH) and bone morphogenetic proteins (BMPs), both of which have been implicated in NTDs. Additionally, glypicans function in the planar cell polarity (PCP) pathway, and several PCP genes have been associated with NTDs. Here, we show that GPC5 orthologs are expressed in the neural tube, and that inhibiting their expression in frog and fish embryos results in NTDs. These results implicate GPC5 as a gene required for normal neural tube development. PMID:23223018

An Overview of the NCC Spray/Monte-Carlo-PDF Computations

NASA Technical Reports Server (NTRS)

Raju, M. S.; Liu, Nan-Suey (Technical Monitor)

2000-01-01

This paper advances the state-of-the-art in spray computations with some of our recent contributions involving scalar Monte Carlo PDF (Probability Density Function), unstructured grids and parallel computing. It provides a complete overview of the scalar Monte Carlo PDF and Lagrangian spray computer codes developed for application with unstructured grids and parallel computing. Detailed comparisons for the case of a reacting non-swirling spray clearly highlight the important role that chemistry/turbulence interactions play in the modeling of reacting sprays. The results from the PDF and non-PDF methods were found to be markedly different and the PDF solution is closer to the reported experimental data. The PDF computations predict that some of the combustion occurs in a predominantly premixed-flame environment and the rest in a predominantly diffusion-flame environment. However, the non-PDF solution predicts wrongly for the combustion to occur in a vaporization-controlled regime. Near the premixed flame, the Monte Carlo particle temperature distribution shows two distinct peaks: one centered around the flame temperature and the other around the surrounding-gas temperature. Near the diffusion flame, the Monte Carlo particle temperature distribution shows a single peak. In both cases, the computed PDF's shape and strength are found to vary substantially depending upon the proximity to the flame surface. The results bring to the fore some of the deficiencies associated with the use of assumed-shape PDF methods in spray computations. Finally, we end the paper by demonstrating the computational viability of the present solution procedure for its use in 3D combustor calculations by summarizing the results of a 3D test case with periodic boundary conditions. For the 3D case, the parallel performance of all the three solvers (CFD, PDF, and spray) has been found to be good when the computations were performed on a 24-processor SGI Origin work-station.

Full 3D visualization tool-kit for Monte Carlo and deterministic transport codes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frambati, S.; Frignani, M.

2012-07-01

We propose a package of tools capable of translating the geometric inputs and outputs of many Monte Carlo and deterministic radiation transport codes into open source file formats. These tools are aimed at bridging the gap between trusted, widely-used radiation analysis codes and very powerful, more recent and commonly used visualization software, thus supporting the design process and helping with shielding optimization. Three main lines of development were followed: mesh-based analysis of Monte Carlo codes, mesh-based analysis of deterministic codes and Monte Carlo surface meshing. The developed kit is considered a powerful and cost-effective tool in the computer-aided design formore » radiation transport code users of the nuclear world, and in particular in the fields of core design and radiation analysis. (authors)« less

High-Fidelity Coupled Monte-Carlo/Thermal-Hydraulics Calculations

NASA Astrophysics Data System (ADS)

Ivanov, Aleksandar; Sanchez, Victor; Ivanov, Kostadin

2014-06-01

Monte Carlo methods have been used as reference reactor physics calculation tools worldwide. The advance in computer technology allows the calculation of detailed flux distributions in both space and energy. In most of the cases however, those calculations are done under the assumption of homogeneous material density and temperature distributions. The aim of this work is to develop a consistent methodology for providing realistic three-dimensional thermal-hydraulic distributions by coupling the in-house developed sub-channel code SUBCHANFLOW with the standard Monte-Carlo transport code MCNP. In addition to the innovative technique of on-the fly material definition, a flux-based weight-window technique has been introduced to improve both the magnitude and the distribution of the relative errors. Finally, a coupled code system for the simulation of steady-state reactor physics problems has been developed. Besides the problem of effective feedback data interchange between the codes, the treatment of temperature dependence of the continuous energy nuclear data has been investigated.

Subtle Monte Carlo Updates in Dense Molecular Systems.

PubMed

Bottaro, Sandro; Boomsma, Wouter; E Johansson, Kristoffer; Andreetta, Christian; Hamelryck, Thomas; Ferkinghoff-Borg, Jesper

2012-02-14

Although Markov chain Monte Carlo (MC) simulation is a potentially powerful approach for exploring conformational space, it has been unable to compete with molecular dynamics (MD) in the analysis of high density structural states, such as the native state of globular proteins. Here, we introduce a kinetic algorithm, CRISP, that greatly enhances the sampling efficiency in all-atom MC simulations of dense systems. The algorithm is based on an exact analytical solution to the classic chain-closure problem, making it possible to express the interdependencies among degrees of freedom in the molecule as correlations in a multivariate Gaussian distribution. We demonstrate that our method reproduces structural variation in proteins with greater efficiency than current state-of-the-art Monte Carlo methods and has real-time simulation performance on par with molecular dynamics simulations. The presented results suggest our method as a valuable tool in the study of molecules in atomic detail, offering a potential alternative to molecular dynamics for probing long time-scale conformational transitions.

Monte Carlo simulation of biomolecular systems with BIOMCSIM

NASA Astrophysics Data System (ADS)

Kamberaj, H.; Helms, V.

2001-12-01

A new Monte Carlo simulation program, BIOMCSIM, is presented that has been developed in particular to simulate the behaviour of biomolecular systems, leading to insights and understanding of their functions. The computational complexity in Monte Carlo simulations of high density systems, with large molecules like proteins immersed in a solvent medium, or when simulating the dynamics of water molecules in a protein cavity, is enormous. The program presented in this paper seeks to provide these desirable features putting special emphasis on simulations in grand canonical ensembles. It uses different biasing techniques to increase the convergence of simulations, and periodic load balancing in its parallel version, to maximally utilize the available computer power. In periodic systems, the long-ranged electrostatic interactions can be treated by Ewald summation. The program is modularly organized, and implemented using an ANSI C dialect, so as to enhance its modifiability. Its performance is demonstrated in benchmark applications for the proteins BPTI and Cytochrome c Oxidase.

Monte Carlo simulation for kinetic chemotaxis model: An application to the traveling population wave

NASA Astrophysics Data System (ADS)

Yasuda, Shugo

2017-02-01

A Monte Carlo simulation of chemotactic bacteria is developed on the basis of the kinetic model and is applied to a one-dimensional traveling population wave in a microchannel. In this simulation, the Monte Carlo method, which calculates the run-and-tumble motions of bacteria, is coupled with a finite volume method to calculate the macroscopic transport of the chemical cues in the environment. The simulation method can successfully reproduce the traveling population wave of bacteria that was observed experimentally and reveal the microscopic dynamics of bacterium coupled with the macroscopic transports of the chemical cues and bacteria population density. The results obtained by the Monte Carlo method are also compared with the asymptotic solution derived from the kinetic chemotaxis equation in the continuum limit, where the Knudsen number, which is defined by the ratio of the mean free path of bacterium to the characteristic length of the system, vanishes. The validity of the Monte Carlo method in the asymptotic behaviors for small Knudsen numbers is numerically verified.

The structure of liquid water by polarized neutron diffraction and reverse Monte Carlo modelling.

PubMed

Temleitner, László; Pusztai, László; Schweika, Werner

2007-08-22

The coherent static structure factor of water has been investigated by polarized neutron diffraction. Polarization analysis allows us to separate the huge incoherent scattering background from hydrogen and to obtain high quality data of the coherent scattering from four different mixtures of liquid H(2)O and D(2)O. The information obtained by the variation of the scattering contrast confines the configurational space of water and is used by the reverse Monte Carlo technique to model the total structure factors. Structural characteristics have been calculated directly from the resulting sets of particle coordinates. Consistency with existing partial pair correlation functions, derived without the application of polarized neutrons, was checked by incorporating them into our reverse Monte Carlo calculations. We also performed Monte Carlo simulations of a hard sphere system, which provides an accurate estimate of the information content of the measured data. It is shown that the present combination of polarized neutron scattering and reverse Monte Carlo structural modelling is a promising approach towards a detailed understanding of the microscopic structure of water.

Massively parallelized Monte Carlo software to calculate the light propagation in arbitrarily shaped 3D turbid media

NASA Astrophysics Data System (ADS)

Zoller, Christian; Hohmann, Ansgar; Ertl, Thomas; Kienle, Alwin

2017-07-01

The Monte Carlo method is often referred as the gold standard to calculate the light propagation in turbid media [1]. Especially for complex shaped geometries where no analytical solutions are available the Monte Carlo method becomes very important [1, 2]. In this work a Monte Carlo software is presented, to simulate the light propagation in complex shaped geometries. To improve the simulation time the code is based on OpenCL such that graphics cards can be used as well as other computing devices. Within the software an illumination concept is presented to realize easily all kinds of light sources, like spatial frequency domain (SFD), optical fibers or Gaussian beam profiles. Moreover different objects, which are not connected to each other, can be considered simultaneously, without any additional preprocessing. This Monte Carlo software can be used for many applications. In this work the transmission spectrum of a tooth and the color reconstruction of a virtual object are shown, using results from the Monte Carlo software.

Monte Carlo study of four dimensional binary hard hypersphere mixtures

NASA Astrophysics Data System (ADS)

Bishop, Marvin; Whitlock, Paula A.

2012-01-01

A multithreaded Monte Carlo code was used to study the properties of binary mixtures of hard hyperspheres in four dimensions. The ratios of the diameters of the hyperspheres examined were 0.4, 0.5, 0.6, and 0.8. Many total densities of the binary mixtures were investigated. The pair correlation functions and the equations of state were determined and compared with other simulation results and theoretical predictions. At lower diameter ratios the pair correlation functions of the mixture agree with the pair correlation function of a one component fluid at an appropriately scaled density. The theoretical results for the equation of state compare well to the Monte Carlo calculations for all but the highest densities studied.