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Sample records for agnano monte spina

  1. Timescales of magmatic processes prior to the ˜4.7 ka Agnano-Monte Spina eruption (Campi Flegrei caldera, Southern Italy) based on diffusion chronometry from sanidine phenocrysts

    NASA Astrophysics Data System (ADS)

    Iovine, Raffaella Silvia; Fedele, Lorenzo; Mazzeo, Fabio Carmine; Arienzo, Ilenia; Cavallo, Andrea; Wörner, Gerhard; Orsi, Giovanni; Civetta, Lucia; D'Antonio, Massimo

    2017-02-01

    Barium diffusion chronometry applied to sanidine phenocrysts from the trachytic Agnano-Monte Spina eruption (˜4.7 ka) constrains the time between reactivation and eruption of magma batches in the Campi Flegrei caldera. Backscattered electron imaging and quantitative electron microprobe measurements on 50 sanidine phenocrysts from representative pumice samples document core-to-rim compositional zoning. We focus on compositional breaks near the crystal rims that record magma mixing processes just prior to eruption. Diffusion times were modeled at a magmatic temperature of 930 °C using profiles based on quantitative BaO point analyses, X-ray scans, and grayscale swath profiles, yielding times ≤60 years between mixing and eruption. Such short timescales are consistent with volcanological and geochronological data that indicate that at least six eruptions occurred in the Agnano-San Vito area during few centuries before the Agnano-Monte Spina eruption. Thus, the short diffusion timescales are similar to time intervals between eruptions. Therefore, the rejuvenation time of magma residing in a shallow reservoir after influx of a new magma batch that triggered the eruption, and thus pre-eruption warning times, may be as short as years to a few decades at Campi Flegrei caldera.

  2. Numerical Simulation of The Coupled Conduit and Atmospheric Dispersal Dynamics of The 4400 Bp Agnano Monte Spina Trachitic Eruption, Phlegrean Fields

    NASA Astrophysics Data System (ADS)

    Papale, P.; Neri, A.; del Seppia, D.; Esposti Ongaro, T.

    The Phlegrean Fields Caldera (PFC), close to Naples, has a very high destructive po- tential in case of activity renewal. We have simulated the coupled dynamics of magma ascent and pyroclast dispersal in the atmosphere of the 4400 BP Agnano Monte Spina eruption, which represents the highest intensity event of the last cycle of activity at PFC. Two sustained magmatic phases of the eruption, corresponding to layers B1 and D1 (De Vita et al., 1999), were selected for the simulations. Boundary conditions for the simulation of the steady phases of magma ascent in the conduit, as well as relevant magma properties, are taken from the literature and from recent results of a coordi- nated project sponsored by the Italian Gruppo Nazionale per la Vulcanologia, devoted to the determination of the eruption dynamics during relevant eruptive events at PFC. Each simulated eruptive phase is assigned a range of mass flow-rate in order to account for uncertainties in the reconstructions. The mass flow-rate of phase B1 ranges from 2.5x10^7 to 10^8 kg/s, that of phase D1 from 5 to 1.8x10^8 kg/s. Water contents were parameterized and allowed to vary from 2 to 6 wt%, and volatiles other than water were neglected. The simulations of conduit flow dynamics were carried out by means of a multiphase flow model previously developed (Papale, 2001), and show a substan- tial increase of pressure distribution in the conduit from the B1 to the D1 phase of the eruption, and within each phase, with increasing assumed mass flow-rate. The depth of fragmentation also increases by 1000-1500 m from phase B1 to D1. Calculated conduit diameters range from 50 to 130 m for phase B1, and from 65 to 150 m for phase D1, depending on the assumed mass flow-rate and water content. From phase B1 to D1, at equal water content, the conduit exit gas volume fraction, gas and particle velocity tend to slightly decrease, while exit pressure and mixture density tend to in- crease. Conduit exit conditions computed by the

  3. Residence times of alkali feldspar phenocrysts from magma feeding the Agnano-Monte Spina Eruption (4.7 ka), Campi Flegrei caldera (Napoli, southern Italy) based on Ba-zonation modelling

    NASA Astrophysics Data System (ADS)

    Iovine, Raffaella Silvia; Wörner, Gerhard; Carmine Mazzeo, Fabio; Arienzo, Ilenia; Fedele, Lorenzo; Civetta, Lucia; D'Antonio, Massimo; Orsi, Giovanni

    2016-04-01

    Timescales governing the development of crustal magma reservoirs are a key for understanding magmatic processes such as ascent, storage and mixing event. An estimate of these timescales can provide important constraints for volcanic hazard assessment of active volcanoes. We studied the Agnano-Monte Spina eruption (A-MS; 4.7 ka; VEI = 4; 0.85 km3 D.R.E. of magma erupted) of the Campi Flegrei caldera, one of the most dangerous volcanic areas on Earth. The A-MS eruption has been fed by magmas varying from more to less evolved trachyte whose variable 87Sr/86Sr and trace elements features suggest magma mixing between two end-members. Ba zonation profiles of alkali feldspar phenocrysts have been determined through combined energy-dispersive and wavelength-dispersive electron microprobe analyses (EDS-WDS-EMPA). We focused on distinct compositional breaks near the rim of the crystals that likely represent the last mixing event prior to eruption. We always chose the steepest gradients close to the crystal rims, taking into account that any effects related to cutting angles or crystal orientation should give longer apparent diffusion times. Two different approaches were undertaken: (1) a quantitative Ba compositional profiles were measured by point analyses along a short transect crossing growth discontinuities and (2) grey-scale profiles were taken parallel to the acquired point profiles. Assuming that Ba dominates the backscattered electron intensities in sanidines, greyscale gradients can be used as a diffusive tracer. BSE images were processed using the ImageJ® software, in order to extract a numerical greyscale profile. In both cases, each profile was interpolated through a non-linear Boltzmann fit curve with the Mathematica® software. A few traverses done at angles smaller than 90° to the compositional boundary interface were corrected by multiplying the distance values by the sinus of the traverse angle relative to the vertical on the interface. Our preliminary

  4. Spina Bifida

    MedlinePlus

    ... de los dientes Video: Getting an X-ray Spina Bifida KidsHealth > For Kids > Spina Bifida Print A A ... uses a wheelchair to get around. What Is Spina Bifida? Someone born with spina bifida has an opening ...

  5. Spina Bifida

    MedlinePlus

    ... Loss > Birth defects & other health conditions > Spina bifida Spina bifida E-mail to a friend Please fill in ... each year in the United States. How can spina bifida affect your baby? Spina bifida can affect how ...

  6. Spina bifida.

    PubMed

    Mitchell, Laura E; Adzick, N Scott; Melchionne, Jeanne; Pasquariello, Patrick S; Sutton, Leslie N; Whitehead, Alexander S

    Spina bifida results from failure of fusion of the caudal neural tube, and is one of the most common malformations of human structure. The causes of this disorder are heterogeneous and include chromosome abnormalities, single gene disorders, and teratogenic exposures. However, the cause is not known in most cases. Up to 70% of spina bifida cases can be prevented by maternal, periconceptional folic acid supplementation. The mechanism underlying this protective effect is unknown, but it is likely to include genes that regulate folate transport and metabolism. Individuals with spina bifida need both surgical and medical management. Although surgical closure of the malformation is generally done in the neonatal period, a randomised clinical trial to assess in utero closure of spina bifida has been initiated in the USA. Medical management is a lifelong necessity for individuals with spina bifida, and should be provided by a multidisciplinary team.

  7. Spina Bifida

    MedlinePlus

    ... with spina bifida has an opening in the spine. A healthy spine is closed to protect the spinal cord, a ... a baby is growing inside its mother, the spine and spinal cord are developing. But sometimes part ...

  8. Spina bifida - resources

    MedlinePlus

    Resources - spina bifida ... The following organizations are good resources for information on spina bifida : March of Dimes -- www.marchofdimes.org/baby/spina-bifida.aspx National Institute of Neurologic Disorders and ...

  9. Spina bifida.

    PubMed

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

    2015-04-30

    Spina bifida is a birth defect in which the vertebral column is open, often with spinal cord involvement. The most clinically significant subtype is myelomeningocele (open spina bifida), which is a condition characterized by failure of the lumbosacral spinal neural tube to close during embryonic development. The exposed neural tissue degenerates in utero, resulting in neurological deficit that varies with the level of the lesion. Occurring in approximately 1 per 1,000 births worldwide, myelomeningocele is one of the most common congenital malformations, but its cause is largely unknown. The genetic component is estimated at 60-70%, but few causative genes have been identified to date, despite much information from mouse models. Non-genetic maternal risk factors include reduced folate intake, anticonvulsant therapy, diabetes mellitus and obesity. Primary prevention by periconceptional supplementation with folic acid has been demonstrated in clinical trials, leading to food fortification programmes in many countries. Prenatal diagnosis is achieved by ultrasonography, enabling women to seek termination of pregnancy. Individuals who survive to birth have their lesions closed surgically, with subsequent management of associated defects, including the Chiari II brain malformation, hydrocephalus, and urological and orthopaedic sequelae. Fetal surgical repair of myelomeningocele has been associated with improved early neurological outcome compared with postnatal operation. Myelomeningocele affects quality of life during childhood, adolescence and adulthood, posing a challenge for individuals, families and society as a whole. For an illustrated summary of this Primer, visit: http://go.nature.com/fK9XNa.

  10. 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

  11. Spina bifida (image)

    MedlinePlus

    Spina bifida is a congenital disorder (birth defect) in which the backbone and spinal canal do not close ... membranes protruding out of an affected infant's back. Spina bifida may also be nearly inconsequential, or may be ...

  12. Spina Bifida Association of America

    MedlinePlus

    ... Support Events & Participants 100 Ways for SB Team Spina Bifida Find a Participant Walk-N-Roll for SB ... Ways for SB Education Days National Conference Team Spina Bifida Walk-N-Roll for Spina Bifida World Congress ...

  13. Test Your Knowledge of Spina Bifida

    MedlinePlus

    ... Past Emails CDC Features Test Your Knowledge of Spina Bifida Language: English Español (Spanish) Recommend on Facebook Tweet ... at every age for those with spina bifida. Spina Bifida Videos The Spina Bifida Experience Managing Medical Care ...

  14. 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 ...

  15. Living with Spina Bifida (at different ages)

    MedlinePlus

    ... Us Information For... Media Policy Makers Living With Spina Bifida Language: English Español (Spanish) Recommend on Facebook Tweet ... of the website provides information about living with spina bifida at different ages. Spina bifida affects the entire ...

  16. AMT investigation in the Solfatara-Pisciarelli-Agnano area: results and further outlook

    NASA Astrophysics Data System (ADS)

    Siniscalchi, Agata; Carlucci, Michela; D'Auria, Luca; Petrillo, Zaccaria; Romano, Gerardo; Tripaldi, Simona

    2015-04-01

    In the framework of the MED-SUV project a 3D electromagnetic survey has been performed in an area covering the Solfatara-Pisciarelli-Agnano (SPA) fumaroles. Previous and newly acquired AudioMagnetoTelluric (AMT) measurements provide a dataset of 43 soundings recorded in the frequency range 0.1-100000 Hz. The 3D data coverage is mainly distributed inside the Solfatara area, while a 5 km long profile crosscuts the SPA area. One of the soundings was carried out close to the San Vito 1 well in order to better constrain the resistivity and geological models. The overarching aim of this study is to provide information on the internal structure along with the extension and link of fluid circulation between the distinct fumarolic areas. Additionally, during active seismic experiment (RICEN) in the Solfatara area, three magnetotelluric stations were operating in order to study the coupled seismo-electromagnetic signals and explore new tools to detect and characterize fluids in depth. 3D inversion of the MT data set is still in progress, while preliminary 2D resistivity inversion modelling along the main profile provides a number of very interesting indications. Largest conductivity anomalies are localized within the first 500 m of depth in all of the three target areas and are clearly connected between the Solfatara and Pisciarelli areas, while relations with the Agnano conductive area are less obvious. Along the profile, at a depth of about 1500 m, the models suggest the passage to a more resistive host rock except below the Solfatara area. 3D inversion would give better insight about the extent and resolution of this anomaly. Finally, the wavelet analysis of electromagnetic signals recorded during RICEN experiment, shows striking interplay between the magnetic field response and the seismic artificial signal. Standing these first results, a more ambitious goal, such as the achievement of an electromagnetic velocity tomography, is going to be pursued.

  17. The Child with Spina Bifida.

    ERIC Educational Resources Information Center

    Anderson, Elizabeth M.; Spain, Bernie

    Intended for parents as well as professionals, the text provides information and practical suggestions on dealing with spina bifida and hydrocephalus. Part I (chapters 1 and 2) concentrates on the medical and physical aspects of the condition with discussions covering such areas as spina bifida's development, locomotor problems, and the role of…

  18. Role of plant growth promoting rhizobacteria and Ag-nano particle in the bioremediation of heavy metals and maize growth under municipal wastewater irrigation.

    PubMed

    Khan, Naeem; Bano, Asghari

    2016-01-01

    The investigation evaluated the role of plant growth promoting rhizobacteria (PGPR) and Ag-nano particle on the growth and metabolism of maize irrigated with municipal wastewater (MW). Three PGPR isolated from MW were identified on the basis of 16S-rRNA gene sequence analyses as Pseudomonas sp., Pseudomonas fluorescence, and Bacillus cereus. The municipal waste water was used to irrigate the maize seeds inoculated with 3 isolated PGPR. The isolated PGPR had catalase and oxidase enzymes, solubilize insoluble bound phosphate and exhibit antifungal and antibacterial activities. The colony forming unit (cfu) of the PGPR was inhibited by Ag-nano particle, but was stimulated by the municipal wastewater. The Ag-nano particles augmented the PGPR induced increase in root area and root length. The root-shoot ratio was also changed with the Ag-nano particles. The plants irrigated with municipal wastewater had higher activities of peroxidase and catalase which were further augmented by Ag-nano particle. The Ag- nano particle application modulated level of ABA (34%), IAA (55%), and GA (82%), increased proline production (70%) and encountered oxidative stress and augmented the bioremediation potential of PGPR for Pb, Cd, and Ni. Municipal wastewater needs to be treated with PGPR and Ag nano particle prior to be used for irrigation. This aims for the better growth of the plant and enhanced bioremediation of toxic heavy metals.

  19. Integrating Pupils with Spina Bifida

    ERIC Educational Resources Information Center

    Halliwell, Miles; Spain, Bernie

    1977-01-01

    A followup survey of parents and teachers of 155 children born with spina bifida, who were mildly handicapped and attended ordinary schools in London, indicated that there were no major problems with the children's placements. (IM)

  20. Spina Bifida: Some Psychological Aspects

    ERIC Educational Resources Information Center

    Fulthorpe, Derek

    1974-01-01

    Examined were the intellectual ability, social adjustment, social competence, and personality characteristics of 33 children, 8-to 15-years-old with spina bifida (a malformation of the spinal cord). (CL)

  1. Spina bifida (degrees of severity) (image)

    MedlinePlus

    Spina bifida is a congenital disorder (birth defect) in which the backbone and spinal canal do not close ... membranes protruding out of an affected infant's back. Spina bifida may also be nearly inconsequential, or may be ...

  2. Learning Among Children with Spina Bifida

    MedlinePlus

    ... Center: 800-621-3141 Learning Among Children with Spina Bifida Overview Parents, teachers and health care professionals have observed that children with Spina Bilda have problems with motor skills, attention, memory ...

  3. 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,…

  4. 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…

  5. Mathematical Development in Spina Bifida

    ERIC Educational Resources Information Center

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

    2009-01-01

    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…

  6. How Do Health Care Providers Diagnose Spina Bifida?

    MedlinePlus

    ... and Publications How do health care providers diagnose spina bifida? Skip sharing on social media links Share this: Page Content Doctors diagnose spina bifida before or after the infant is born. Spina ...

  7. What Are the Treatments for Spina Bifida and Related Conditions?

    MedlinePlus

    ... Resources and Publications What are the treatments for spina bifida & related conditions? Skip sharing on social media links Share this: Page Content Open Spina Bifida An infant with open spina bifida (myelomeningocele), in ...

  8. Are There Disorders or Conditions Associated with Spina Bifida?

    MedlinePlus

    ... Publications Are there disorders or conditions associated with spina bifida? Skip sharing on social media links Share this: ... Health issues are different for each person with spina bifida. Open spina bifida (myelomeningocele)—in which the spinal ...

  9. Spina Bifida. NICHCY Disability Fact Sheet #12

    ERIC Educational Resources Information Center

    National Dissemination Center for Children with Disabilities, 2011

    2011-01-01

    "Spina bifida" is one of the most common birth defects in the United States, affecting some 1,500 babies each year. Spina bifida happens during the first month or so of pregnancy and means that the baby's spine did not close completely. Damage to the nerves and the spinal cord may result. Following a brief story about a child with a…

  10. Spina Bifida and Folic Acid Awareness

    ERIC Educational Resources Information Center

    Exceptional Parent, 2007

    2007-01-01

    Spina bifida is the most common, permanently disabling birth defect in the United States. It is a birth defect that involves incomplete formation of the spine during the first month of pregnancy--often before a woman even knows she is pregnant. Everyday, an average of eight babies are born with spina bifida or a similar birth defect of the brain…

  11. Educational Placement of Children with Spina Bifida.

    ERIC Educational Resources Information Center

    Lauder, Calvin E.; And Others

    1979-01-01

    Procedures of school placement for 38 children (ages 5 to 18 years) with spina bifida in 23 school districts in western New York State were studied 5 years after a mandated process was enacted. (Author)

  12. Mathematical development in spina bifida.

    PubMed

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

    2009-01-01

    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.

  13. 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

  14. In utero repair of spina bifida.

    PubMed

    Moldenhauer, Julie S

    2014-08-01

    Open spina bifida or myelomeningocele (MMC) is the most common congenital malformation of the central nervous system compatible with long-term survival and is associated with significant lifelong disabilities. Postnatal care of MMC involves covering the exposed spinal cord, infection prevention, and ventricular shunting for hydrocephalus. The aim of postnatal MMC surgery is not to reverse or prevent the neurologic injury seen in MMC, but to palliate. The neurologic defects result from primary incomplete neurulation and secondary chronic in utero damage to the exposed neural elements through mechanical and chemical trauma-the two-hit hypothesis. With the ability to accurately diagnose spina bifida prenatally and the concept of the two-hit hypothesis, in utero repair to decrease exposure and alter the antenatal course of neurologic destruction was conceived. Through animal models and human pilot studies, the feasibility of fetal spina bifida repair was demonstrated. Subsequently, the prospective randomized multicenter Management of Myelomeningocele Study (MOMS trial) revealed a decreased need for shunting, reversal of hindbrain herniation, and preservation of neurologic function, making in utero repair an accepted care alternative for select women carrying a fetus with spina bifida. This article will highlight the background and rationale for in utero repair, and the progression to becoming an alternative standard of care. The future directions of fetal spina bifida repair will also be addressed.

  15. Spina Bifida. Fact Sheet = Espina Bifida. Hojas Informativas Sobre Discapacidades.

    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 (spina bifida occulta, meningocele, and myelomeningocele), outlines their incidence, describes characteristics of individuals with spina bifida, and reviews educational implications. The fact sheet discusses the need for many children with myelomeningocele to learn to manage…

  16. Diagnosis of spina bifida on ultrasound: always termination?

    PubMed

    Trudell, Amanda S; Odibo, Anthony O

    2014-04-01

    Open spina bifida is a non-lethal fetal anomaly. Significant advances in the prevention, diagnosis and treatment of open spina bifida have been made over the past 75 years. The most significant strategy for the prevention of open spina bifida has been with folic acid supplementation; however, further investigation into the complicated role that genetics and the environment play in metabolism are coming to light. Ultrasound is the gold standard diagnostic tool for spina bifida. Three-dimensional ultrasound and magnetic resonance imaging are also beginning to play a role in the characterisation of the open spina bifida spinal lesion. Lesion level has been closely correlated to short and long-term outcomes, and prenatal characterisation of lesion level on ultrasound is important for patient counselling. Long-term outcomes of people living with spina bifida are available and should be used for non-directive patient counselling about pregnancy choices for women with open spina bifida.

  17. 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…

  18. 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…

  19. The Cognitive Phenotype of Spina Bifida Meningomyelocele

    ERIC Educational Resources Information Center

    Dennis, Maureen; Barnes, Marcia A.

    2010-01-01

    A cognitive phenotype is a product of both assets and deficits that specifies what individuals with spina bifida meningomyelocele (SBM) can and cannot do and why they can or cannot do it. In this article, we review the cognitive phenotype of SBM and describe the processing assets and deficits that cut within and across content domains, sensory…

  20. 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…

  1. The cognitive phenotype of spina bifida meningomyelocele.

    PubMed

    Dennis, Maureen; Barnes, Marcia A

    2010-01-01

    A cognitive phenotype is a product of both assets and deficits that specifies what individuals with spina bifida meningomyelocele (SBM) can and cannot do and why they can or cannot do it. In this article, we review the cognitive phenotype of SBM and describe the processing assets and deficits that cut within and across content domains, sensory modality, and material, including studies from our laboratory and other investigations. We discuss some implications of the SBM cognitive phenotype for assessment, rehabilitation, and research.

  2. Optimizing Health Care for Children with Spina Bifida

    ERIC Educational Resources Information Center

    Liptak, Gregory S.; El Samra, Ahmad

    2010-01-01

    The health care needs of children with spina bifida are complex. They need specialists, generalists, and an integrated system to deliver this complex care and to align and inform all the providers. Most research in spina bifida has been focused on narrow medical outcomes; it has been noncollaborative, based on small samples of convenience, with no…

  3. Symposium on Spina Bifida (Denver, Colorado, November, 1969).

    ERIC Educational Resources Information Center

    Colorado Univ., Denver. Medical Center.

    The objectives of the symposium were to define the problems of the child with spina bifida and to present practical means of management, using a multi-disciplinary team approach. Eight papers defining the problem cover the epidemiology of spina bifida, pathophysiology, musculoskeletal defects, incontinence of bladder and bowel, problems of…

  4. Optimizing Health Care for Adults with Spina Bifida

    ERIC Educational Resources Information Center

    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…

  5. 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…

  6. Sociodemographic Attributes and Spina Bifida Outcomes

    PubMed Central

    Schechter, Michael S.; Liu, Tiebin; Soe, Minn; Swanson, Mark; Ward, Elisabeth; Thibadeau, Judy

    2015-01-01

    Background A National Spina Bifida Patient Registry (NSBPR) was begun in 2009 to help understand the natural history of spina bifida (SB) and the effects of treatments provided by SB clinics. We used the NSBPR to explore the relationship of sociodemographic characteristics with SB outcomes. Methods Using NSBPR data collected in 2009 to 2012, we examined the unadjusted association between demographic characteristics and 4 SB outcomes: bowel continence, bladder continence, mobility, and presence of pressure sores. We then developed multivariable logistic models to explore these relationships while controlling for SB clinic, SB type, and level of lesion. Results Data were available on 2054 patients <22 years of age from 10 SB clinics. In the multivariable models, older age groups were more likely to have continence and pressure sores and less likely to be community ambulatory. Males and patients without private insurance were less likely to be continent and community ambulatory. Non-Hispanic blacks were less likely to be continent. Level of lesion was associated with all outcomes; SB type was associated with all but pressure sores; and all outcomes except community ambulation showed significant variation across clinic sites. Conclusions Sociodemographic attributes are associated with SB outcomes. In particular, males, non-Hispanic blacks, and patients without private insurance have less favorable outcomes, and age has an impact as well. These characteristics need to be considered by clinicians who care for this patient population and factored into case-mix adjustment when evaluating variation in clinical and functional outcomes among different SB clinics. PMID:25780069

  7. Spina Bifida: Pathogenesis, Mechanisms, and Genes in Mice and Humans.

    PubMed

    Mohd-Zin, Siti W; Marwan, Ahmed I; Abou Chaar, Mohamad K; Ahmad-Annuar, Azlina; Abdul-Aziz, Noraishah M

    2017-01-01

    Spina bifida is among the phenotypes of the larger condition known as neural tube defects (NTDs). It is the most common central nervous system malformation compatible with life and the second leading cause of birth defects after congenital heart defects. In this review paper, we define spina bifida and discuss the phenotypes seen in humans as described by both surgeons and embryologists in order to compare and ultimately contrast it to the leading animal model, the mouse. Our understanding of spina bifida is currently limited to the observations we make in mouse models, which reflect complete or targeted knockouts of genes, which perturb the whole gene(s) without taking into account the issue of haploinsufficiency, which is most prominent in the human spina bifida condition. We thus conclude that the need to study spina bifida in all its forms, both aperta and occulta, is more indicative of the spina bifida in surviving humans and that the measure of deterioration arising from caudal neural tube defects, more commonly known as spina bifida, must be determined by the level of the lesion both in mouse and in man.

  8. Identification of novel CELSR1 mutations in spina bifida.

    PubMed

    Lei, Yunping; Zhu, Huiping; Yang, Wei; Ross, M Elizabeth; Shaw, Gary M; Finnell, Richard H

    2014-01-01

    Spina bifida is one of the most common neural tube defects (NTDs) with a complex etiology. Variants in planar cell polarity (PCP) genes have been associated with NTDs including spina bifida in both animal models and human cohorts. In this study, we sequenced all exons of CELSR1 in 192 spina bifida patients from a California population to determine the contribution of CELSR1 mutations in the studied population. Novel and rare variants identified in these patients were subsequently genotyped in 190 ethnically matched control individuals. Six missense mutations not found in controls were predicted to be deleterious by both SIFT and PolyPhen. Two TG dinucleotide repeat variants were individually detected in 2 spina bifida patients but not detected in controls. In vitro functional analysis showed that the two TG dinucleotide repeat variants not only changed subcellular localization of the CELSR1 protein, but also impaired the physical association between CELSR1 and VANGL2, and thus diminished the ability to recruit VANGL2 for cell-cell contact. In total, 3% of our spina bifida patients carry deleterious or predicted to be deleterious CELSR1 mutations. Our findings suggest that CELSR1 mutations contribute to the risk of spina bifida in a cohort of spina bifida patients from California.

  9. Spina Bifida: Pathogenesis, Mechanisms, and Genes in Mice and Humans

    PubMed Central

    Abou Chaar, Mohamad K.; Ahmad-Annuar, Azlina

    2017-01-01

    Spina bifida is among the phenotypes of the larger condition known as neural tube defects (NTDs). It is the most common central nervous system malformation compatible with life and the second leading cause of birth defects after congenital heart defects. In this review paper, we define spina bifida and discuss the phenotypes seen in humans as described by both surgeons and embryologists in order to compare and ultimately contrast it to the leading animal model, the mouse. Our understanding of spina bifida is currently limited to the observations we make in mouse models, which reflect complete or targeted knockouts of genes, which perturb the whole gene(s) without taking into account the issue of haploinsufficiency, which is most prominent in the human spina bifida condition. We thus conclude that the need to study spina bifida in all its forms, both aperta and occulta, is more indicative of the spina bifida in surviving humans and that the measure of deterioration arising from caudal neural tube defects, more commonly known as spina bifida, must be determined by the level of the lesion both in mouse and in man. PMID:28286691

  10. Identification of Novel CELSR1 Mutations in Spina Bifida

    PubMed Central

    Lei, Yunping; Zhu, Huiping; Yang, Wei; Ross, M. Elizabeth; Shaw, Gary M.; Finnell, Richard H.

    2014-01-01

    Spina bifida is one of the most common neural tube defects (NTDs) with a complex etiology. Variants in planar cell polarity (PCP) genes have been associated with NTDs including spina bifida in both animal models and human cohorts. In this study, we sequenced all exons of CELSR1 in 192 spina bifida patients from a California population to determine the contribution of CELSR1 mutations in the studied population. Novel and rare variants identified in these patients were subsequently genotyped in 190 ethnically matched control individuals. Six missense mutations not found in controls were predicted to be deleterious by both SIFT and PolyPhen. Two TG dinucleotide repeat variants were individually detected in 2 spina bifida patients but not detected in controls. In vitro functional analysis showed that the two TG dinucleotide repeat variants not only changed subcellular localization of the CELSR1 protein, but also impaired the physical association between CELSR1 and VANGL2, and thus diminished the ability to recruit VANGL2 for cell-cell contact. In total, 3% of our spina bifida patients carry deleterious or predicted to be deleterious CELSR1 mutations. Our findings suggest that CELSR1 mutations contribute to the risk of spina bifida in a cohort of spina bifida patients from California. PMID:24632739

  11. Spina bifida and other neural tube defects.

    PubMed

    Northrup, H; Volcik, K A

    2000-01-01

    NTDs, resulting from failure of the neural tube to close during the fourth week of embryogenesis, are the most common severely disabling birth defects in the United States, with a frequency of approximately 1 of every 2000 births. Neural tube malformations involving the spinal cord and vertebral arches are referred to as spina bifida, with severe types of spina bifida involving protrusion of the spinal cord and/or meninges through a defect in the vertebral arch. Depending on the level of the lesion, interruption of the spinal cord at the site of the spina bifida defect causes paralysis of the legs, incontinence of urine and feces, anesthesia of the skin, and abnormalities of the hips, knees, and feet. Two additional abnormalities often seen in children with spina bifida include hydrocephalus and the Arnold-Chiari type II malformation. Despite the physical and particular learning disabilities children with spina bifida must cope with, participation in individualized educational programs can allow these children to develop skills necessary for autonomy in adulthood. Advances in research to uncover the molecular basis of NTDs is enhanced by knowledge of the link between both the environmental and genetic factors involved in the etiology of NTDs. The most recent development in NTD research for disease-causing genes is the discovery of a genetic link to the most well-known environmental cause of neural tube malformation, folate deficiency in pregnant women. Nearly a decade ago, periconceptional folic acid supplementation was proven to decrease both the recurrence and occurrence of NTDs. The study of folate and its association with NTDs is an ongoing endeavor that has led to numerous studies of different genes involved in the folate metabolism pathway, including the most commonly studied thermolabile mutation (C677T) in the MTHFR gene. An additional focus for NTD research involves mouse models that exhibit both naturally occurring NTDs, as well as those created by

  12. Language development in children with spina bifida.

    PubMed

    Fletcher, Jack M; Barnes, Marcia; Dennis, Maureen

    2002-09-01

    Spina bifida meningomyelocele (SBM) is the most common severely disabling birth defect in North America. It is a disorder of the central nervous system that includes, in addition to the defining spinal dysraphism, congenital malformations of the cerebellum and corpus callosum that, along with hydrocephalus, produces a range of cognitive and motor difficulties, including language. In the language domain, many children with SBM demonstrate adequate development of language at the level of form and content (grammar and lexicon). However, most children with SBM experience significant difficulties in the construction of meaning and in pragmatic communication, both of which require flexible language processing in real time. Assessment and intervention should specifically attend to the development of meaning construction and semantic-pragmatic communication.

  13. 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

  14. Osteoporosis in paediatric patients with spina bifida

    PubMed Central

    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. Objective 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. Methods 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 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. PMID:22330186

  15. Psychosocial and family functioning in spina bifida.

    PubMed

    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 SB support a resilience-disruption view of family functioning. That is, the presence of a child with SB disrupts normative family functioning but many families adapt to such disruption and exhibit considerable resilience in the face of adversity. Parents of youth with SB, and particularly those from lower socio-economic status (SES) homes, are at-risk for psychosocial difficulties. Individuals with SB are at-risk for developing internalizing symptoms, attention problems, educational difficulties, social maladjustment, and delays in the development of independent functioning. Emerging adults are often delayed in achieving milestones related to this stage of development (e.g., vocational and educational achievements). Methodologically sound, longitudinal, and theory-driven studies of family and psychosocial functioning are needed, as are randomized family-based intervention trials, to promote adaptive functioning and better psychosocial outcomes in families of individuals with SB.

  16. Psychosocial and Family Functioning in Spina Bifida

    PubMed Central

    Holmbeck, Grayson N.; Devine, Katie A.

    2010-01-01

    A developmentally-oriented bio-neuropsychosocial model is introduced to explain 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 SB support a resilience-disruption view of family functioning. That is, the presence of a child with SB disrupts normative family functioning, but many families adapt to such disruption and exhibit considerable resilience in the face of adversity. Parents of youth with SB, and particularly those from lower SES homes, are at-risk for psychosocial difficulties. Individuals with SB are at-risk for developing internalizing symptoms, attention problems, educational difficulties, social maladjustment, and delays in the development of independent functioning. Emerging adults are often delayed in achieving milestones related to this stage of development (e.g., vocational and educational achievements). Methodologically-sound, longitudinal, and theory-driven studies of family and psychosocial functioning are needed, as are randomized family-based intervention trials, to promote adaptive functioning and better psychosocial outcomes in families of individuals with SB. PMID:20419770

  17. Optimizing health care for children with spina bifida.

    PubMed

    Liptak, Gregory S; El Samra, Ahmad

    2010-01-01

    The health care needs of children with spina bifida are complex. They need specialists, generalists, and an integrated system to deliver this complex care and to align and inform all the providers. Most research in spina bifida has been focused on narrow medical outcomes; it has been noncollaborative, based on small samples of convenience, with no comparison groups, and without consistent standards of measurement. Models of health, like the World Health Organization International Classification of Functioning, Disability, and Health Model can help to broaden the scope of future research. Using methods from other pediatric conditions like the patient registry (cystic fibrosis), gene bank (autism), and collaborative research (leukemia), researchers can improve the quality of future studies. Research questions related to the process of care and to specific nonsurgical conditions associated with spina bifida are reviewed in this article.

  18. 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…

  19. 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)

  20. 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.…

  1. Reaching for Independence: Counseling Implications for Youth with Spina Bifida

    ERIC Educational Resources Information Center

    Brislin, Dawn C.

    2008-01-01

    Spina bifida, a congenital physical disability, is indirectly associated with difficulties in scholastic achievement, social development, and self-determination. Environment can have an impact on psychosocial development and impede functioning academically, socially, and vocationally. Counselors must be aware of the societal atmosphere to identify…

  2. Physical Education for Students with Spina Bifida: Mothers' Perspectives

    ERIC Educational Resources Information Center

    An, Jihoun; Goodwin, Donna L.

    2007-01-01

    This study described the meaning 7 mothers of children with spina bifida ascribed to their children's physical education, the mothers' roles in the schools, and the importance of the IEP in home and school communication. The stories of 4 mothers of elementary and 3 mothers of secondary aged children were gathered using the phenomenological methods…

  3. Fractures in spina bifida from childhood to young adulthood.

    PubMed

    Trinh, A; Wong, P; Brown, J; Hennel, S; Ebeling, P R; Fuller, P J; Milat, F

    2017-01-01

    This study assessed the prevalence and types of fractures in spina bifida and examined risk factors for fracture. Fracture prevalence was highest in childhood and reduced in adolescence and young adulthood. The importance of maintaining mobility is highlighted by the increased risk of fracture in those who are non-ambulatory.

  4. 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,…

  5. Isolated and ventriculomegaly-associated cases of spina bifida in genetic counseling: focus on fetal pathology.

    PubMed

    Joó, József Gábor; Csaba, Ákos; Szigeti, Zsanett; Rigó, János

    2013-07-01

    Cases of spina bifida alone and in association with ventriculomegaly represent important but different malformations according to clinical characteristics. In our study, we analyzed the data on pregancies terminated because of isolated cases (n=307) and ventriculomegaly-associated cases (n=372) of spina bifida. In spina bifida cases in association with hydrocephalus, positive obstetric history was found approximately 1.5 times more frequently than in the isolated ones. The incidence of positive genetic history was nearly two-fold in the latter cases. In isolated cases of spina bifida, associated malformations were more common than in cases of spina bifida and ventriculomegaly together. The most frequent associated malformations were those of the urogenital system (in cases of spina bifida: 11.1%; in cases of SB+V: 9.14%). The risk of recurrence of SB+V is significantly higher than that of isolated SB (8.9% vs. 2.1%). It can be concluded that positive genetic history is more common in cases of isolated spina bifida. Malformations out of the nervous system are more commonly observed in cases of isolated spina bifida. During the prenatal diagnostics of spina bifida, sonography must focus on malformations of the urogenital system.

  6. 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...-Spina Bifida and Covered Birth Defects General § 21.8012 Vocational training program for certain children of Vietnam veterans—spina bifida and covered birth defects. VA will provide an evaluation to...

  7. 77 FR 42229 - Gruma Corporation, Spina Bifida Association, March of Dimes Foundation, American Academy of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration 21 CFR Part 172 Gruma Corporation, Spina Bifida Association... Corporation, Spina Bifida Association, March of Dimes Foundation, American Academy of Pediatrics, Royal DSM...

  8. 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…

  9. Changes in Medical Practice towards the Child with Spina Bifida: Implications for Schools.

    ERIC Educational Resources Information Center

    Tew, Brian

    1987-01-01

    The improved surgical management of children with spina bifida is among the reasons for a decreased number of severely physically and/or mentally affected children. Such improvements have resulted in more spina bifida children attending British ordinary schools and fewer attending special schools. (Author/DB)

  10. 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…

  11. 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)

  12. 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…

  13. 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…

  14. From Wheelchair to Cane: Elective Transtibial Amputations in a Patient with Spina Bifida.

    PubMed

    Mayo, Amanda; Berbrayer, David

    2015-11-01

    Spina bifida is associated with foot deformities, which may lead to foot ulcers, osteomyelitis, and limb amputation. Calcanectomy and Symes amputations have been reported successful in spina bifida. There is lack of evidence for transtibial amputations. This case describes a 27-yr-old woman with L4 level spina bifida who underwent bilateral transtibial amputations. She ambulated with bilateral ankle foot orthoses and canes until age 22. At age 22, she had bilateral foot reconstructive surgeries complicated by nonunion, ulcerations, and osteomyelitis. She was using a wheelchair by age 25. She had elective bilateral transtibial amputations at age 27 for progressive osteomyelitis. Four weeks after amputations, she was fit with bilateral prostheses. On completion of 2 mos of rehabilitation, she ambulated with a cane. This case demonstrates good functional outcomes after transtibial amputations in a young spina bifida patient. Prosthetic fitting should be considered for similar, previously high functioning spina bifida patients with transtibial amputation(s).

  15. Architecture of the rectus abdominis, quadratus lumborum, and erector spinae.

    PubMed

    Delp, S L; Suryanarayanan, S; Murray, W M; Uhlir, J; Triolo, R J

    2001-03-01

    Quantitative descriptions of muscle architecture are needed to characterize the force-generating capabilities of muscles. This study reports the architecture of three major trunk muscles: the rectus abdominis, quadratus lumborum, and three columns of the erector spinae (spinalis thoracis, longissimus thoracis and iliocostalis lumborum). Musculotendon lengths, muscle lengths, fascicle lengths, sarcomere lengths, pennation angles, and muscle masses were measured in five cadavers. Optimal fascicle lengths (the fascicle length at which the muscle generates maximum force) and physiologic cross-sectional areas (the ratio of muscle volume to optimal fascicle length) were computed from these measurements. The rectus abdominis had the longest fascicles of the muscles studied, with a mean (S.D.) optimal fascicle length of 28.3 (4.2)cm. The three columns of the erector spinae had mean optimal fascicle lengths that ranged from 6.4 (0.6)cm in the spinalis thoracis to 14.2 (2.1)cm in the iliocostalis lumborum. The proximal portion of the quadratus lumborum had a mean optimal fascicle length of 8.5 (1.5)cm and the distal segment of this muscle had a mean optimal fascicle length of 5.6 (0.9)cm. The physiologic cross-sectional area of the rectus abdominis was 2.6 (0.9)cm(2), the combined physiologic cross-sectional area of the erector spinae was 11.6 (1.8)cm(2), and the physiologic cross-sectional area of the quadratus lumborum was 2.8 (0.5)cm(2). These data provide the basis for estimation of the force-generating potential of these muscles.

  16. 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.

  17. Sacral fatigue fractures in children with sacral spina bifida occulta

    PubMed Central

    Hama, Shingo; Sakai, Toshinori; Higashino, Kosaku; Abe, Mitsunobu; Nagamachi, Akihiro; Sairyo, Koichi

    2016-01-01

    In this report, we present two cases of 9-year-old children with spina bifida occulta (SBO) of the sacrum, who were diagnosed with sacral fatigue fractures. In both patients, MRI showed a linear signal void and high signal in sacral ala on the short tau inversion recovery sequence. Sacral SBO at the same level of the sacral fracture was observed in each patient on computed tomography images. These lesions healed with rest. This is the first literature reporting cases with sacral stress fractures who had SBO at the same level of fracture. PMID:26196371

  18. 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

  19. Ultrasonographic clues for diagnosis of spina bifida occulta in children

    PubMed Central

    Cinar, Hasibe Gokce; Uner, Cigdem; Ucan, Berna; Eksioglu, Ayse Secil; Pala, Melek; Yildiz, Yasemin Tasci; Cakmakci, Selma; Yikmaz, Hulya Seker

    2016-01-01

    Background The aim of the current study was to find out if spinal ultrasonography might have a predictive potential for detection of spina bifida occulta (SBO) in pediatric nocturnal enuresis patients. Methods A total of 108 children (58 females, 50 males) with a mean age of 8 (range, 6–15) years diagnosed for nocturnal enuresis in our tertiary care center were included in this cross-sectional analysis. Half of the cases (n=54, 50%) were found to have SBO, while the other half did not have SBO. After obtaining radiographs and computed tomography examinations of L5-S1 vertebra, patients were examined by spinal ultrasound regarding radiologic clues which may aid in the detection of SBO. Results The clues of “single and double echogeneous cap signs and the V-shaped tip of spine” were found useful for diagnosing SBO at levels of L5 and S1 in pediatric patients suspected for SBO. Receiver operating curve (ROC) curve analysis of CT and ultrasonographic clues for diagnosis of SBO on S1 level revealed that these clues yielded a comparable diagnostic accuracy to CT. Areas under curve for CT and studied ultrasonographic clues were are 0.667±0.053 and 0.907±0.032 (P<0.001) respectively. Conclusions Ultrasonography seems to be a useful and practical diagnostic tool for diagnosing spina bifida. However, to implement our ultrasonographic criteria in routine radiological practice, further studies in larger series are warranted. PMID:27942474

  20. 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

  1. From Traditional Usage to Pharmacological Evidence: A Systematic Mini-Review of Spina Gleditsiae

    PubMed Central

    Yang, Xiao; Yin, Weiping

    2016-01-01

    Spina Gleditsiae is an important herb with various medicinal properties in traditional and folk medicinal systems of East Asian countries. In China through the centuries, it has been traditionally used as a source of drugs for anticancer, detoxication, detumescence, apocenosis, and antiparasites effects. Recently, an increasing number of studies have been reported regarding its chemical constituents and pharmacological activities. To further evidence the traditional use, phytochemicals, and pharmacological mechanisms of this herb, a systematic literature review was performed herein for Spina Gleditsiae. The review approach consisted of searching several web-based scientific databases including PubMed, Web of Science, and Elsevier using the keywords “Spina Gleditsiae”, “Zao Jiao Ci”, and “Gleditsia sinensis”. Based on the proposed criteria, 17 articles were evaluated in detail. According to the reviewed data, it is quite evident that Spina Gleditsiae contains a number of bioactive phytochemical components, which account for variety medicinal values including anticancer, anti-inflammatory, antiatherogenic, antimicrobial, antiallergic, and antivirus activities. The phytochemical and pharmacological studies reviewed herein strongly underpin a fundamental understanding of herbal Spina Gleditsiae and support its ongoing clinical uses in China. The further phytochemical evaluation, safety verification, and clinical trials are expected to progress Spina Gleditsiae-based development to finally transform the traditional TCM herb Spina Gleditsiae to the valuable authorized drug. PMID:27433183

  2. 1987 Volvo award in basic science. The morphology of the lumbar erector spinae.

    PubMed

    Macintosh, J E; Bogduk, N

    1987-09-01

    The lumbar erector spinae consists of two muscles--iliocostalis lumborum and longissimus thoracis--each with distinct thoracic and lumbar parts. The thoracic parts consist of tiny muscle bellies with segmental origins from the thorax and long caudal tendons that form the erector spinae aponeurosis. The lumbar fibers arise from the lumbar accessory processes and the L1-4 transverse processes, and insert independently of the erector spinae aponeurosis into the ilium. The intrinsic lumbar fibers of the erector spinae are poorly described in the literature, and the existence of the iliocostalis lumborum pars lumborum has rarely been recognized even though it constitutes a substantial portion of the total muscle mass acting directly on the lumbar vertebrae.

  3. 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)

  4. Language Use without Comprehension: A Suggested Methodology for the Clinical Evaluation of Spina Bifida Children.

    ERIC Educational Resources Information Center

    Culatta, Barbara

    1978-01-01

    Three spina bifida children (mean age 66 months) were studied to illustrate the comprehension deficit and to demonstrate how evaluations can be structured. Available from Eterna Press, P.O. Box 19, Bolingbrook, Illinois 60439. (Author/PHR)

  5. A Camp-based Intervention Targeting Independence Among Individuals with Spina Bifida

    PubMed Central

    O’Mahar, Kerry; Jandasek, Barbara; Zukerman, Jill

    2010-01-01

    Objective To design and evaluate a camp-based intervention, the goal of which was to increase independence among children, adolescents, and adults with spina bifida. Methods An intervention targeting independence was embedded within a typical week long camp experience. The intervention consisted of the following: collaborative (i.e., parent and camper) goal identification, group sessions consisting of psycho-education and cognitive tools, and goal monitoring by camp counselors. Camper and parent report of demographic variables, goal attainment, spina bifida knowledge, and independence were gathered. Interventionist report of adherence to the treatment manual was also collected. Results Campers made significant gains in individual goals, management of spina bifida responsibilities, and independence with general spina bifida tasks, with medium effect sizes observed in goal attainment. Conclusions Results indicated that significant progress was made on individually oriented goals from pre- to post-camp. Design issues are discussed. PMID:20026569

  6. Early Information Processing among Infants with and without Spina Bifida

    PubMed Central

    Taylor, Heather B.; Landry, Susan H.; Barnes, Marcia; Swank, Paul; Cohen, Leslie B.; Fletcher, Jack

    2010-01-01

    This study focuses on the development of early visual information processing among infants with Spina Bifida (SB) compared to typically developing infants using the habituation-dishabituation paradigm. Analyses were conducted in two stages. First infants were evaluated to determine if 18 month old infants (SB = 47; Control =40) differed in their ability to shift attention and habituate to two female faces, as well as their responses to composite and novel stimuli. Second, relations between these variables and infant motor and mental functioning were evaluated. The results of the study indicated that difficulties with visual attention skills can be detected as early as 18 months-of-age among infants with SB. Infants with SB differed significantly from controls on attention getting. Although there were no differences found on habituation and composite tasks, infants with SB differed significantly from controls on their ability to dishabituate. Implications are discussed. PMID:20488543

  7. Cortical control of erector spinae muscles during arm abduction in humans.

    PubMed

    Kuppuswamy, Annapoorna; Catley, Maria; King, Nicolas K K; Strutton, Paul H; Davey, Nick J; Ellaway, Peter H

    2008-04-01

    Abduction of one arm preferentially activates erector spinae muscles on the other side to stabilise the body. We hypothesise that the corticospinal drive to the arm abductors and the erector spinae may originate from the same hemisphere. In 18 subjects, transcranial magnetic stimulation (TMS) was applied using an angle double-cone coil placed symmetrically over the vertex. Motor evoked potentials (MEP) could not be evoked systematically seated at rest but could be evoked bilaterally in erector spinae muscles during unilateral arm abduction. TMS was applied at 110% and 120% motor threshold (MT) for the contralateral erector spinae muscle when an arm was abducted against resistance. The electromyographic (EMG) activity in the erector spinae at L4 vertebral level during contralateral arm abduction was significantly higher (P<0.05) than in the ipsilateral erector spinae. The mean (+/-S.E.M.) latencies of MEPs in the contralateral muscle to TMS at 120%MT (left 16.0+/-0.8 ms; right 17.0+/-0.8 ms) were significantly (P<0.05) longer than in the ipsilateral erector spinae (13.9+/-1.0 ms; 16.6+/-0.4 ms). In two of six subjects from the same group, it was possible to elicit MEPs by TMS applied selectively to one hemisphere using a figure-of-eight coil. MEPs ipsilateral to the TMS had longer latencies than contralateral MEPs. The study revealed an unexpectedly longer rather than shorter latency of the MEP recorded from the lumbar erector spinae muscles when co-activated during abduction of the opposite arm. A speculative explanation is that TMS might activate back muscles contralateral to arm abduction via an uncrossed, ipsilateral corticospinal tract that is slower conducting than the conventional crossed corticospinal tract. The study has implications for the design of measures to promote recovery and rehabilitation of motor function in disorders such as stroke and spinal cord injury.

  8. Neuropsychological assessment of attention in children with spina bifida

    PubMed Central

    Vinck, Anja; Mullaart, Reinier; Rotteveel, Jan; Maassen, Ben

    2009-01-01

    Background Children with the severe form of spina bifida (SBM: spina bifida with myelomeningocele with accompanying hydrocephalus) may manifest attention deficits, and have a similar psychological profile to children with hydrocephalus due to other etiologies. It is unclear to what extent tests to assess attention in SBM are confounded by the accompanying cognitive or visual-motor impairments. The aim of this study was to analyse attention functions by administering two different types of attention tests, one with high and the other with low cognitive and motor requirements. This enabled the possible interaction between attention and cognitive and motor impairment to be assessed. Methods The study group comprised 31 children with SBM with shunted hydrocephalus. Twenty children with SB-only formed a closely matched comparison group. Of these, 19 children with SBM and 18 with SB had a full-scale IQ (FSIQ) higher than 70. All had undergone spinal surgery and all children with SBM had been shunted within the first months of life. Between 6 and 15 years of age, the children were assessed on focused and sustained attention, encoding, and distractibility/impulsivity, using both traditional tests and computerized attention tests. Results Compared to the SB group, attention scores of children with SBM were lower on the traditional tests, but when interfering cognitive and visual-motor requirements were eliminated using the computerised tasks, most differences disappeared. Furthermore, in contrast to traditional attention tasks, computerized tests showed no significant correlations with IQ-scores and visual-motor skills. Conclusion Assessment of attention functions in children with SBM by traditional tests may be misleading, because this paediatric population with complex cerebral malformations has difficulty with the cognitive and visual-motor requirements. To control for these interactions, the use of both traditional and computerized attention tests is recommended. PMID

  9. Spina bifida and anencephaly prevalence--United States, 1991-2001.

    PubMed

    Mathews, T J; Honein, Margaret A; Erickson, J David

    2002-09-13

    Spina bifida and anencephaly are serious birth defects. To reduce the occurrence of these birth defects, the Food and Drug Administration authorized the fortification of all enriched cereal grain products with folic acid in March 1996, with compliance mandatory by January 1998. This report reviews data reported to CDC's National Center for Health Statistics (NCHS) regarding spina bifida and anencephaly prevalence for live births in the United States during 1991-2001. Since 1989, NCHS has compiled birth defect data from checkboxes that appear on birth certificates. For consistency in trends, this report uses data for 1991-2001 from all U.S. reporting areas except Maryland, New Mexico, and New York. Data for 2001 are preliminary. During 1996-2001, a 23% decline occurred in neural tube defects (spina bifida and anencephaly combined). Spina bifida declined 24% during this period, and anencephaly declined 21%. The United States has experienced declines in spina bifida and anencephaly cases since folic acid fortification of all enriched cereal grain products. The observed declines have translated into approximately 920 infants being born without these serious defects each year. Continued monitoring of the occurrence of spina bifida and anencephaly will be necessary to evaluate the effectiveness of folic acid fortification.

  10. Injury Risk for Research Subjects With Spina Bifida Occulta in a Repeated Impact Study: A Case Review.

    DTIC Science & Technology

    1996-01-01

    USAARL Report No. 96-05 Injury Risk for Research Subjects With Spina Bifida Occulta in a Repeated Impact Study: A Case Review By John P. Albano...TITLE (Include Security Classification) Injury risk for research subjects with spina bifida occulta in a repeated impact study: A case review 12...block number) FIELD GROUP SUB-GROUP repeated impact, spina bifida occulta, axial loading 19. ABSTRACT (Continue on reverse if necessary and identify by

  11. 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.

  12. Orthopaedic management of the lower extremities in spina bifida.

    PubMed

    Szalay, E A

    1987-01-01

    Myelodysplasia is a multisystem disease that requires a multidisciplinary approach. The orthopaedist is often the first to identify a changing neurologic picture or deformity and must work closely with neurosurgical colleagues to identify correctable neurologic lesions. The role of the orthopaedist begins at the birth of the child with spina bifida. At this time, the level of neurologic involvement can be determined. Education of the parents can then begin by outlining the expected ambulatory potential of the child, and predicting deformities or complications that might be anticipated depending on the level of neurologic involvement. The orthopaedist must also emphasize the extreme importance of neurosurgical care in preventing deterioration of neurologic function, so that goals for ambulation and musculoskeletal function can be achieved. As the child gets older, motor milestones paralleling those of a normal child should be sought with use of a corner chair or sitting device, followed by the use of a standing frame if needed. If appropriate, the child will then progress to full-control braces, with weaning as determined by neurologic level of involvement . Long-term mobility may be achieved by bracing or by the use of a wheelchair. A realistic approach must be taken in goal-setting, so that a child is not pressured to achieve unrealistic goals yet is enabled to achieve full functional capacity.

  13. Interhemispheric effective and functional cortical connectivity signatures of spina bifida are consistent with callosal anomaly.

    PubMed

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

    2012-01-01

    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.

  14. Rare deleterious variants in GRHL3 are associated with human spina bifida.

    PubMed

    Lemay, Philippe; De Marco, Patrizia; Emond, Alexandre; Spiegelman, Dan; Dionne-Laporte, Alexandre; Laurent, Sandra; Merello, Elisa; Accogli, Andrea; Rouleau, Guy A; Capra, Valeria; Kibar, Zoha

    2017-03-08

    Neural tube defects, including spina bifida, are among the most common birth defects caused by failure of neural tube closure during development. They have a complex etiology involving largely undetermined environmental and genetic factors. Previous studies in mouse models have implicated the transcription factor Grhl3 as an important factor in the pathogenesis of spina bifida. In the present study, we conducted a resequencing analysis of GRHL3 in a cohort of 233 familial and sporadic cases of spina bifida. We identified two novel truncating variants: one homozygous frameshift variant, p.Asp16Aspfs*10, in two affected siblings and one heterozygous intronic splicing variant, p.Ala318Glyfs*26. We also identified five missense variants, one of which was demonstrated to reduce the activation of gene targets in a luciferase reporter assay. With the previously identified p.Arg391Cys variant, eight variants were found in GRHL3. Comparison of the variant rate between our cohort and the ExAC database identified a significant enrichment of deleterious variants in GRHL3 in the whole gene and the transactivation region in spina bifida patients. These data provide strong evidence for a role of GRHL3 as a predisposing factor to spina bifida and will help dissect the complex etiology and pathogenic mechanisms of these malformations.

  15. 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

    ... 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...

  16. 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…

  17. Chiropractic Care of Acute Low Back Pain and Incidental Spina Bifida Occulta: A Case Report

    PubMed Central

    Cofano, Gregory P.; Anderson, Benjamin C.; Stumpff, Eric R.

    2014-01-01

    Objective The purpose of this case report is to describe chiropractic care of an adolescent with acute low back pain and incidental finding of spina bifida occulta managed with high-velocity low-amplitude manipulation. Clinical Features A 10-year-old boy was referred for chiropractic care by his pediatrician for the management of low back pain after a fall 3 days prior. Examination and medical records revealed the patient also had spina bifida occulta at the level of L5. Intervention and Outcome High-velocity low-amplitude treatment for lower back pain showed resolution of patient's pain after 6 visits. No adverse effects were reported. Conclusion An adolescent patient with lower back pain and incidental finding of spina bifida occulta improved with a course of care that included with high-velocity low-amplitude manipulation therapy. PMID:25435841

  18. 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

  19. Altered microRNA expression profiles in a rat model of spina bifida

    PubMed Central

    Qin, Pan; Li, Lin; Zhang, Da; Liu, Qiu-liang; Chen, Xin-rang; Yang, He-ying; Fan, Ying-zhong; Wang, Jia-xiang

    2016-01-01

    MicroRNAs (miRNAs) are dynamically regulated during neurodevelopment, yet few reports have examined their role in spina bifida. In this study, we used an established fetal rat model of spina bifida induced by intragastrically administering olive oil-containing all-trans retinoic acid to dams on day 10 of pregnancy. Dams that received intragastric administration of all-trans retinoic acid-free olive oil served as controls. The miRNA expression profile in the amniotic fluid of rats at 20 days of pregnancy was analyzed using an miRNA microarray assay. Compared with that in control fetuses, the expression of miRNA-9, miRNA-124a, and miRNA-138 was significantly decreased (> 2-fold), whereas the expression of miRNA-134 was significantly increased (> 4-fold) in the amniotic fluid of rats with fetuses modeling spina bifida. These results were validated using real-time quantitative reverse-transcription polymerase chain reaction. Hierarchical clustering analysis of the microarray data showed that these differentially expressed miRNAs could distinguish fetuses modeling spina bifida from control fetuses. Our bioinformatics analysis suggested that these differentially expressed miRNAs were associated with many cytological pathways, including a nervous system development signaling pathway. These findings indicate that further studies are warranted examining the role of miRNAs through their regulation of a variety of cell functional pathways in the pathogenesis of spina bifida. Such studies may provide novel targets for the early diagnosis and treatment of spina bifida. PMID:27127493

  20. Preliminary study of novel, timed walking tests for children with spina bifida or cerebral palsy

    PubMed Central

    Kane, Kyra J; Lanovaz, Joel; Bisaro, Derek; Oates, Alison; Musselman, Kristin E

    2016-01-01

    Objective: Walking assessment is an important aspect of rehabilitation practice; yet, clinicians have few psychometrically sound options for evaluating walking in highly ambulatory children. The purpose of this study was to evaluate the validity and reliability of two new measures of walking function—the Obstacles and Curb tests—relative to the 10-Meter Walk test and Timed Up and Go test in children with spina bifida or cerebral palsy. Methods: A total of 16 ambulatory children with spina bifida (n=9) or cerebral palsy (n=7) (9 boys; mean age 7years, 7months; standard deviation 3years, 4months) and 16 age- and gender-matched typically developing children participated. Children completed the walking tests, at both self-selected and fast speeds, twice. To evaluate discriminative validity, scores were compared between typically developing and spina bifida/cerebral palsy groups. Within the spina bifida/cerebral palsy group, inter-test correlations evaluated convergent validity and intraclass correlation coefficients evaluated within-session test–retest reliability. Results: At fast speeds, all tests showed discriminative validity (p<0.006 for typically developing and spina bifida/cerebral palsy comparisons) and convergent validity (rho=0.81–0.90, p⩽0.001, for inter-test correlations). At self-selected speeds, only the Obstacles test discriminated between groups (p=0.001). Moderately strong correlations (rho=0.73–0.78, p⩽0.001) were seen between the 10-Meter Walk test, Curb test, and Timed Up and Go test. Intraclass correlation coefficients ranged from 0.81 to 0.97, with higher test–retest reliability for tests performed at fast speeds rather than self-selected speeds. Conclusion: The Obstacles and Curb tests are promising measures for assessing walking in this population. Performing tests at fast walking speeds may improve their validity and test–retest reliability for children with spina bifida/cerebral palsy. PMID:27493754

  1. Altered microRNA expression profiles in a rat model of spina bifida.

    PubMed

    Qin, Pan; Li, Lin; Zhang, Da; Liu, Qiu-Liang; Chen, Xin-Rang; Yang, He-Ying; Fan, Ying-Zhong; Wang, Jia-Xiang

    2016-03-01

    MicroRNAs (miRNAs) are dynamically regulated during neurodevelopment, yet few reports have examined their role in spina bifida. In this study, we used an established fetal rat model of spina bifida induced by intragastrically administering olive oil-containing all-trans retinoic acid to dams on day 10 of pregnancy. Dams that received intragastric administration of all-trans retinoic acid-free olive oil served as controls. The miRNA expression profile in the amniotic fluid of rats at 20 days of pregnancy was analyzed using an miRNA microarray assay. Compared with that in control fetuses, the expression of miRNA-9, miRNA-124a, and miRNA-138 was significantly decreased (> 2-fold), whereas the expression of miRNA-134 was significantly increased (> 4-fold) in the amniotic fluid of rats with fetuses modeling spina bifida. These results were validated using real-time quantitative reverse-transcription polymerase chain reaction. Hierarchical clustering analysis of the microarray data showed that these differentially expressed miRNAs could distinguish fetuses modeling spina bifida from control fetuses. Our bioinformatics analysis suggested that these differentially expressed miRNAs were associated with many cytological pathways, including a nervous system development signaling pathway. These findings indicate that further studies are warranted examining the role of miRNAs through their regulation of a variety of cell functional pathways in the pathogenesis of spina bifida. Such studies may provide novel targets for the early diagnosis and treatment of spina bifida.

  2. Proteomic analysis of amniotic fluid of pregnant rats with spina bifida aperta.

    PubMed

    Shan, Liping; Fan, Yang; Li, Hui; Liu, Wei; Gu, Hui; Zhou, Fenghua; Yuan, Zhengwei

    2012-02-02

    Congenital spina bifida aperta is a common congenital malformation in children and has an incidence of 1‰ to 5‰ in China. However, we currently lack specific biomarkers for screening or prenatal diagnosis and there is no method to entirely cure or prevent such defects. In this study, we used two-dimensional gel electrophoresis (2-DE)/mass spectrometry (MS) to characterize differentially expressed proteins in amniotic-fluid samples (AFSs) of embryonic day (E) 17.5 rat fetuses with spina bifida aperta induced by retinoic acid (RA). We identified five proteins differentially expressed in AFSs of spina bifida aperta, including three upregulated proteins (transferrin, alpha-1 antiproteinase and signal recognition particle receptor, B subunit [SRPRB] 55 kDa), two downregulated proteins (apolipoprotein A IV [APO A4] and Srprb 77 kDa). Specifically, we found 11 alpha-1 fetoprotein (AFP) fragments that were downregulated and 35 AFP fragments that were upregulated in AFSs from embryos with spina bifida aperta. Of the downregulated AFP fragments, 72.7% (8/11) were confined to the AFP N-terminus (amino acids [aas] 25-440) and 77.1% (27/35) of upregulated AFP fragments were confined to the AFP C-terminus (aas 340-596). We also confirmed APO A4 and AFP by immunoblot analysis. This is the first comparative proteomic study of AFSs from rat fetuses with spina bifida aperta. We demonstrate proteomic alterations in the AFS of spina bifida aperta, which may provide new insights in neural tube defects and contribute to the prenatal screening.

  3. 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.

  4. Quantitative diffusion tensor imaging and intellectual outcomes in spina bifida

    PubMed Central

    Hasan, Khader M.; Sankar, Ambika; Halphen, Christopher; Kramer, Larry A.; Ewing-Cobbs, Linda; Dennis, Maureen; Fletcher, Jack M.

    2011-01-01

    Object Patients with spina bifida (SB) have variable intellectual outcomes. The authors used diffusion tensor (DT) imaging to quantify whole-brain volumes of gray matter, white matter, and cerebrospinal fluid (CSF), and perform regional quantitative microstructural assessments of gray matter nuclei and white matter tracts in relation to intellectual outcomes in patients with SB. Methods Twenty-nine children with myelomeningoceles and 20 age- and sex-matched children with normal neural tube development underwent MR imaging with DT image acquisition and assessments of intelligence. The DT imaging-derived metrics were the fractional anisotropy (FA), axial (parallel), and transverse (perpendicular) diffusivities. These metrics were also used to segment the brain into white matter, gray matter, and CSF. A region-of-interest analysis was conducted of the white and gray matter structures implicated in hydrocephalus. Results The amount of whole-brain gray matter was decreased in patients with SB, with a corresponding increase in CSF (p < 0.0001). Regional transverse diffusivity in the caudate nucleus was decreased (p < 0.0001), and the corresponding FA was increased (p < 0.0001), suggesting reduced dendritic branching and connectivity. Fractional anisotropy in the posterior limb of the internal capsule increased in the myelomeningocele group (p = 0.02), suggesting elimination of some divergent fascicles; in contrast, the FA in several white matter structures (such as the corpus callosum genu [p < 0.001] and arcuate fasciculus) was reduced, suggesting disruption of myelination. Diffusion tensor imaging-metrics involving gray matter volume and the caudate nucleus, but not other structures, predicted variations in IQ (r = 0.37-0.50; p < 0.05). Conclusions Diffusion tensor imaging-derived metrics provide noninvasive neuronal surrogate markers of the pathogenesis of SB and predict variations in general intellectual outcomes in children with this condition. PMID:18590401

  5. Quality of life in spina bifida: importance of parental hope

    PubMed Central

    Kirpalani, H.; Parkin, P.; Willan, A.; Fehlings, D.; Rosenbaum, P.; King, D; Van Nie, A. J

    2000-01-01

    BACKGROUND AND AIMS—Prognosis in spina bifida (SB) is often based only on neurological deficits present at birth. We hypothesised that both parental hope and the neurophysical examination predict quality of life in children and adolescents with SB.
METHODS—A previously validated disease and age specific health related quality of life (HRQL) instrument was posted to families of children (aged 5-12 years) and adolescents (aged 13-20 years) with SB. We measured parental hope, determined the child's current physical function, and obtained retrospective data on the neonatal neurophysical examination (NPE). Regression analysis modelled HRQL firstly as a dependent variable on parental hope and NPE ("birth status"); and secondly on parental hope and current physical function ("current function").
RESULTS—Response rates were 71% (137 of 194) for families of children, and 54% (74 of 138) for families of adolescents. NPE data were available for 121 children and 60 adolescents. In children, the birth status model predicted 26% of the variability (R2 hope 21%) compared with 23% of the variability (R2 hope 23%)in the adolescents. The current function model explained 47% of the variability (R2 hope 19%) in children compared with 31% of the variability (R2 hope 24%) in the adolescents.
CONCLUSIONS—In both age groups, parental hope was more strongly associated with the HRQL than neonatal or current physical deficits. A prospective study is required to determine whether a causal relation exists between parental hope and HRQL of children and adolescents with SB.

 PMID:10999858

  6. Monte Carlo Benchmark

    SciTech Connect

    2010-10-20

    The "Monte Carlo Benchmark" (MCB) is intended to model the computatiional performance of Monte Carlo algorithms on parallel architectures. It models the solution of a simple heuristic transport equation using a Monte Carlo technique. The MCB employs typical features of Monte Carlo algorithms such as particle creation, particle tracking, tallying particle information, and particle destruction. Particles are also traded among processors using MPI calls.

  7. Effects of lumbar stabilization exercises on the flexion-relaxation phenomenon of the erector spinae.

    PubMed

    Park, San-Seong; Choi, Bo-Ram

    2016-06-01

    [Purpose] This study evaluated the differences in the flexion-relaxation phenomenon (FRP) of the right and left erector spinae muscles in asymptomatic subjects and the effect of lumbar stabilization exercises on these differences. [Subjects and Methods] Twenty-six participants (12 in the exercise group and 14 in the control group) with a difference in the FRP in the right and left erector spinae muscles were recruited from among healthy students attending Silla University. The exercise group performed two lumbar stabilization exercises (back bridge exercise and hand-knee exercise) for 4 weeks. The control group did not exercise. [Results] No significant group-by-exercise interaction was found. The right and left erector spinae muscles did show a difference in FRP between the control and exercise groups (119.2 ± 69.2 and 131.1 ± 85.2 ms, respectively). In addition, the exercise group showed a significant decrease in post-exercise (50.0 ± 27.0 ms) compared to pre-exercise (112.3 ± 41.5 ms) differences in the right and left FRP. [Conclusion] These results suggest that lumbar stabilization exercises may counter asymmetry of the FRP in the erector spinae muscles, possibly preventing low back pain in the general population.

  8. 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…

  9. 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…

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. The Effects of Cognitive Strategy Instruction on the Mathematical Problem Solving of Adolescents with Spina Bifida

    ERIC Educational Resources Information Center

    Coughlin, Judy; Montague, Marjorie

    2011-01-01

    This study investigated the effects of cognitive strategy instruction on the mathematical problem solving of three adolescents with spina bifida. Conditions of the multiple-baseline across-individuals design included baseline, two levels of treatment, posttesting, and maintenance. Treatment 1 focused on one-step math problems, and Treatment 2…

  15. 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…

  16. Health Risk Behaviors in Spina Bifida: The Need for Clinical and Policy Action

    ERIC Educational Resources Information Center

    Sawin, Kathleen J.; Brei, Timothy J.

    2012-01-01

    Health risk behaviors (HRBs) in adults with spina bifida such as poor diet, reduced physical activity, increased television viewing time, and substance abuse often have their genesis in early childhood. They are potentially preventable but if not addressed aggressively may continue to progress across the lifespan. Findings from a population-based…

  17. Quality of Life in Individuals with Spina Bifida: A Research Update

    ERIC Educational Resources Information Center

    Sawin, Kathleen J.; Bellin, Melissa H.

    2010-01-01

    Quality of life (QOL) is an important concept for individuals with chronic health conditions. Measuring and supporting QOL in children, adolescents, and adults with spina bifida (SB) may be especially unique given the broad range of complex health and rehabilitative challenges they encounter. This article provides a research update on (a)…

  18. 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…

  19. 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…

  20. 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…

  1. 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…

  2. Role of Early Parenting and Motor Skills on Development in Children with Spina Bifida

    ERIC Educational Resources Information Center

    Lomax-Bream, Laura E.; Taylor, Heather B.; Landry, Susan H.; Barnes, Marcia A.; Fletcher, Jack M.; Swank, Paul

    2007-01-01

    The impact of parenting and motor skills on the development of cognitive, language, and daily living skills was examined in 165 children (91 with spina bifida, SB), from 6-36 months of age. Motor scores significantly influenced cognitive, language, and daily living skills. Higher quality parenting was associated with higher levels of development…

  3. Risk and Protective Influences in the Lives of Siblings of Youths with Spina Bifida

    ERIC Educational Resources Information Center

    Bellin, Melissa H.; Kovacs, Pamela J.; Sawin, Kathleen J.

    2008-01-01

    The impact of childhood chronic health conditions like spina bifida (SB) is a shared family experience. However, the lived experience of siblings is not well known. One hundred and fifty-five brothers and sisters of a child with SB responded to an open-ended question included in an anonymous self-administered mail questionnaire designed to enhance…

  4. Spatial Knowledge of Children with Spina Bifida in a Virtual Large-Scale Space

    ERIC Educational Resources Information Center

    Wiedenbauer, Gunnar; Jansen-Osmann, Petra

    2006-01-01

    The spatial knowledge of 18 children with spina bifida and 18 healthy control children (matched according to sex, age, and verbal IQ) was investigated in a computer-simulated environment. All children had to learn a route through a virtual floor system containing 18 landmarks. Controlling for cognitive abilities, the results revealed that children…

  5. Effects of lumbar stabilization exercises on the flexion-relaxation phenomenon of the erector spinae

    PubMed Central

    Park, San-seong; Choi, Bo-ram

    2016-01-01

    [Purpose] This study evaluated the differences in the flexion-relaxation phenomenon (FRP) of the right and left erector spinae muscles in asymptomatic subjects and the effect of lumbar stabilization exercises on these differences. [Subjects and Methods] Twenty-six participants (12 in the exercise group and 14 in the control group) with a difference in the FRP in the right and left erector spinae muscles were recruited from among healthy students attending Silla University. The exercise group performed two lumbar stabilization exercises (back bridge exercise and hand-knee exercise) for 4 weeks. The control group did not exercise. [Results] No significant group-by-exercise interaction was found. The right and left erector spinae muscles did show a difference in FRP between the control and exercise groups (119.2 ± 69.2 and 131.1 ± 85.2 ms, respectively). In addition, the exercise group showed a significant decrease in post-exercise (50.0 ± 27.0 ms) compared to pre-exercise (112.3 ± 41.5 ms) differences in the right and left FRP. [Conclusion] These results suggest that lumbar stabilization exercises may counter asymmetry of the FRP in the erector spinae muscles, possibly preventing low back pain in the general population. PMID:27390399

  6. 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)

  7. 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…

  8. Awareness of folic acid use increases its consumption, and reduces the risk of spina bifida.

    PubMed

    Kondo, Atsuo; Morota, Nobuhito; Date, Hiroaki; Yoshifuji, Kazuhisa; Morishima, Toshibumi; Miyazato, Minoru; Shirane, Reizo; Sakai, Hideki; Pooh, Kyong Hon; Watanabe, Tomoyuki

    2015-07-14

    The majority of neural tube defects were believed to be folic acid (FA)-preventable in the 1990s. The Japanese government recommended women planning pregnancy to take FA supplements of 400 μg/d in 2000, but the incidence of spina bifida has not decreased. We aimed to evaluate the OR of having an infant with spina bifida for women who periconceptionally took FA supplements and the association between an increase in supplement use and possible promoters for the increase. This is a case-control study which used 360 case women who gave birth to newborns afflicted with spina bifida, and 2333 control women who gave birth to healthy newborns during the first 12 years of this century. They were divided into two 6-year periods; from 2001 to 2006 and from 2007 to 2012. Logistic regression analyses were conducted to compute OR between cases and controls. The adjusted OR of having an infant with spina bifida for supplement users was 0.48 in the first period, and 0.53 in the second period. The proportion of women who periconceptionally consumed supplements significantly increased from 10 % in the first period to 30 % in the second period. Awareness of the preventive role of FA was a promoter for an increase in supplement use, and thus an FA campaign in high school seems rational and effective. The failure of the current public health policy is responsible for an epidemic of spina bifida. Mandatory food fortification with FA is urgent and long overdue in Japan.

  9. Sonic Hedgehog Signaling Affected by Promoter Hypermethylation Induces Aberrant Gli2 Expression in Spina Bifida.

    PubMed

    Lu, Xiao-Lin; Wang, Li; Chang, Shao-Yan; Shangguan, Shao-Fang; Wang, Zhen; Wu, Li-Hua; Zou, Ji-Zhen; Xiao, Ping; Li, Rui; Bao, Yi-Hua; Qiu, Z-Y; Zhang, Ting

    2016-10-01

    GLI2 is a key mediator of the sonic hedgehog (Shh) signaling pathway and plays an important role in neural tube development during vertebrate embryogenesis; however, the role of gli2 in human folate-related neural tube defects remains unclear. In this study, we compared methylation status and polymorphisms of gli2 between spina bifida patients and a control group to explore the underlying mechanisms related to folate deficiency in spina bifida. No single nucleotide polymorphism was found to be significantly different between the two groups, although gli2 methylation levels were significantly increased in spina bifida samples, accompanied by aberrant GLI2 expression. Moreover, a prominent negative correlation was found between the folate level in brain tissue and the gli2 methylation status (r = -0.41, P = 0.014), and gli2 hypermethylation increased the risk of spina bifida with an odds ratio of 12.45 (95 % confidence interval: 2.71-57.22, P = 0.001). In addition, we established a cell model to illustrate the effect of gli2 expression and the accessibility of chromatin affected by methylation. High gli2 and gli1 mRNA expression was detected in 5-Aza-treated cells, while gli2 hypermethylation resulted in chromatin inaccessibility and a reduced association with nuclear proteins containing transcriptional factors. More meaningful to the pathway, the effect gene of the Shh pathway, gli1, was found to have a reduced level of expression along with a decreased expression of gli2 in our cell model. Aberrant high methylation resulted in the low expression of gli2 in spina bifida, which was affected by the change in chromatin status and the capacity of transcription factor binding.

  10. Scorecard for spina bifida research, prevention, and policy - A development process.

    PubMed

    Kancherla, Vijaya; Walani, Salimah R; Weakland, Aliki P; Bauwens, Lieven; Oakley, Godfrey P; Warf, Benjamin C

    2017-02-09

    Spina bifida is a serious and largely preventable neural tube birth defect and an important cause of mortality and lifelong disability. The People and Organizations United for Spina Bifida and Hydrocephalus (PUSH!) Global Alliance was formed in 2014 to provide a common platform for various organizations worldwide to raise the visibility of spina bifida and hydrocephalus. In its formative phase, the alliance recognized that in order to accelerate surveillance, prevention, and care for these conditions, there was a need to provide an evidence-based assessment of how nations are performing in specific areas. In this paper, we describe the impetus for, and the process of, developing country-level scorecards for spina bifida surveillance, prevention and care. The PUSH! Executive Committee formulated a comprehensive list of six actionable indicators measuring availability of published studies on population-based folate studies; surveillance of prevalence and mortality; prevention-based policies; access to care; and quality of life associated with spina bifida. Rubrics were developed to score each country on the aforementioned indicators. Country scores were pooled across each indicator and the composite scores ranged between zero and three if there was a need for improvement, four and five if they were in good standing, or six for an excellent status. The scorecard included country-specific recommendations assimilated from the literature and published guidelines to aid policy makers in accelerating surveillance and prevention, and improving the care and quality of life indicators. For comparison, country-level scorecards were grouped by WHO-regions. Score cards were made available publicly through the website "www.pu-sh.org".

  11. Monte Carlo Example Programs

    SciTech Connect

    Kalos, M.

    2006-05-09

    The Monte Carlo example programs VARHATOM and DMCATOM are two small, simple FORTRAN programs that illustrate the use of the Monte Carlo Mathematical technique for calculating the ground state energy of the hydrogen atom.

  12. Can atlas spina bifida-occulta be a cause of cervicogenic headaches?

    PubMed

    Adigo, Amégninou Mawuko Yao; Agoda-Kousséma, Lama Kegdigoma; Agbotsou, Ignéza Komi; Adambounou, Kokou; Bakpatina-Batako, Kpalma Duga; Djagnikpo, Oni; Adjénou, Komlanvi Victor

    2015-01-01

    Cervicogenic headaches are a nosologic entity recently recognized. In our common practice, we have noticed a relative frequency of the atlas spina-bifida occulta during the brain CT scan realized for headaches without cranio-encephalic causes or any other anomaly of the upper cervical region. The aim of this study was to determine a possible connection between cervicogenic headaches (CEH) and atlas spina-bifida occulta. A 2 years prospective and descriptive study in 20 black patients having an atlas spina-bifida occulta diagnosed with a brain CT scan. The mean age of the patients was 43.17 ± 18.35 years (extremes: 24 and 72 years). A light female predominance was noticed (sex-ratio = 1.5). The frequency of symptomatic spina-bifida was 1.72 % (17 cases). The mean age at onset was 31.84 years. The pain was sub-occipital in 14 cases, occipital in 8 cases, bilateral in 12 cases and unilateral in 5 cases. The mean duration of the attacks was 72 ± 24 h and the pain intensity was moderate (16 cases); mean and range were 3.6 and 3-6. The frequency of attacks varied between 1 per 7 months (n = 2) and 2 per week (n = 1) in those with non-daily headache. One attack per 5-7 weeks was the most commonly occurring attack frequency. The pain was reproduced by the pressure of the occipital region or upper cervical in 15 cases. The mean number of criteria was five and there was a strong positive correlation between criteria and CEH (χ (2) = 45.57; V = 0.62). The associated signs were photophobia and nausea in one case each. Indomethacin, Ergotamine and/or Sumatriptan were without any antalgic effect in 16 cases. Pain ceased after an anesthetic blockade of C2 (16 cases). The results show that atlas spina-bifida occulta is not involved in CEH pure form genesis. On a small sample, the atlas spina-bifida seems to be a cause of CEH associated with headache and disorders of the neck.

  13. 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.

  14. Effect of chronic knee osteoarthritis on flexion-relaxation phenomenon of the erector spinae in elderly females

    PubMed Central

    Jeong, Yeon-Gyu; Jeong, Yeon-Jae; Koo, Jung-Wan

    2016-01-01

    [Purpose] This study investigated the flexion-relaxation phenomenon of the erector spinae in elderly women with chronic knee osteoarthritis and determined whether the flexion-relaxation phenomenon can be used as a pain evaluation tool in such cases. [Subjects and Methods] Seventeen elderly females with chronic knee osteoarthritis and 13 healthy young females voluntarily participated in this study. They performed three postural positions in 15 s: trunk flexion, complete trunk flexion, and trunk extension, each for 5 s. While these positions were held, muscle activation of the thoracic and lumbar erector spinae were measured using surface electromyography. The flexion-relaxation rate was determined by dividing the values for trunk extension by those of complete trunk flexion and by dividing the values for trunk flexion by those of complete trunk flexion. [Results] According to our results, the flexion-relaxation phenomenon was different between healthy young and elderly females with chronic knee osteoarthritis. Specifically, there was a difference in the left thoracic erector spinae muscle, but not in the left and right lumbar erector spinae or right thoracic spinae muscle. [Conclusion] Our study demonstrated that the erector spinae muscle flexion-relaxation phenomenon can be used as a pain evaluation tool in elderly females with chronic knee osteoarthritis. PMID:27512244

  15. Spatial cognition and motor development: a study of children with spina bifida.

    PubMed

    Jansen-Osmann, Petra; Wiedenbauer, Gunnar; Heil, Martin

    2008-04-01

    The purpose of this study was to examine the relation between motor development and spatial cognition. The sample was 20 children with Spina bifida (M age: 11.4 yr., SD = 1.7) and 20 healthy children as controls (M age: 11.8, SD = 1.8 yr.). An experimental assessment of motor development in spatial cognition in a simulated virtual maze by school-age children is lacking. In this study children with Spina bifida, who were impaired in walking since birth, completed four visuospatial tasks in a small-scale space (Mental Rotation, Water-Level Task, Embedded Figures Test, Visual Short-term Memory Test), and a spatial behaviour and knowledge task in a virtual maze. These children showed poorer performance than children in the control group on most measures. The results are discussed with respect to theoretical implications and further research.

  16. Improved Survival Among Children with Spina Bifida in the United States

    PubMed Central

    Shin, Mikyong; Kucik, James E.; Siffel, Csaba; Lu, Chengxing; Shaw, Gary M.; Canfield, Mark A.; Correa, Adolfo

    2015-01-01

    Objective To evaluate trends in survival among children with spina bifida by race/ethnicity and possible prognostic factors in 10 regions of the United States. Study design A retrospective cohort study was conducted of 5165 infants with spina bifida born during 1979-2003, identified by 10 birth defects registries in the United States. Survival probabilities and adjusted hazard ratios were estimated for race/ethnicity and other characteristics using the Cox proportional hazard model. Results During the study period, the 1-year survival probability among infants with spina bifida showed improvements for whites (from 88% to 96%), blacks (from 79% to 88%), and Hispanics (from 88% to 93%). The impact of race/ethnicity on survival varied by birth weight, which was the strongest predictor of survival through age 8. There was little racial/ethnic variation in survival among children born of very low birth weight. Among children born of low birth weight, the increased risk of mortality to Hispanics was approximately 4-6 times that of whites. The black-white disparity was greatest among children born of normal birth weight. Congenital heart defects did not affect the risk of mortality among very low birth weight children but increased the risk of mortality 4-fold among children born of normal birth weight. Conclusions The survival of infants born with spina bifida has improved; however, improvements in survival varied by race/ethnicity, and blacks and Hispanics continued to have poorer survival than whites in the most recent birth cohort from 1998-2002. Further studies are warranted to elucidate possible reasons for the observed differences in survival. PMID:22727874

  17. Long-term outcome of transanal irrigation for children with spina bifida.

    PubMed

    Choi, E K; Han, S W; Shin, S H; Ji, Y; Chon, J H; Im, Y J

    2014-12-23

    Study design:Experimental, prospective study.Objectives:We evaluated the long-term clinical efficacy of transanal irrigation (TAI) and its effect on the quality of life of spina bifida children and their caregivers.Setting:Republic of Korea.Method:Forty-four spina bifida pediatric patients with constipation, fecal incontinence or both, underwent a TAI program at our spina bifida clinic between December 2010 and October 2013. The children and their caregivers were evaluated using a self-administered questionnaire before TAI and at 3 months and 3 years after initiation of the program.Results:Successful treatment outcome was achieved in 38 (86.4%) children after a mean follow-up duration of 33 months (range, 30-36). The mean number of fecal incontinence episodes per week, the number of diaper changes and the total time for bowel care per day before the program decreased at the latest follow-up examination from 7.3 to 0.4 (P<0.001), 1.6 to 0.2 (P<0.001) and 29.2 to 19.4 min (P=0.038), respectively. These results remained constant from short-term follow-up at 3 months to 3 years. Caregivers and children could go out more often (P=0.002), and the emotional impact of bowel care on caregivers decreased (P<0.001). The reported mean overall satisfaction with TAI was 8/10. The common adverse effect during TAI was abdominal discomfort (60.5%).Conclusion:We observed a sustained significant improvement in defecation symptoms and quality of life for 3 years in spina bifida children who underwent continuous TAI.Spinal Cord advance online publication, 23 December 2014; doi:10.1038/sc.2014.234.

  18. Applying a knowledge-to-action framework for primary prevention of spina bifida in tropical Africa.

    PubMed

    Claude, Kasereka M; Juvenal, Kwibuka L; Hawkes, Michael

    2012-04-01

    Maternal periconceptual folate supplementation reduces the incidence of neural tube defects; however, in settings where population-level food fortification is not available, it is not clear how best to promote this prevention strategy. Guided by a knowledge-to-action methodology, we used mixed quantitative and qualitative methods to define the local disease burden, then designed, implemented and evaluated a culturally tailored educational intervention in eastern Democratic Republic of Congo, where resource limitations and threats to human security contribute to restricted capacity for the prevention and management of congenital malformations. A descriptive case series of 27 patients undergoing surgery for spina bifida demonstrated a short-term mortality of 15% and long-term disability in survivors. A survey of knowledge, attitudes and practices demonstrated a low level of folate awareness (53%) among women of reproductive age. Focus group discussions revealed exotic aetiologic views, significant gender issues and several barriers to folate use. A culturally tailored radio broadcast and an educational video were designed and produced locally based on qualitative and quantitative findings. Evaluation of the video documented high levels of viewer satisfaction and unequivocal knowledge gain (P ≤ 0.001). We conclude that spina bifida poses a significant burden on affected patients and their families in the African context, but folate is underutilized as a prevention strategy. Patient education through video media results in increased awareness and understanding of spina bifida and folate, a first step in empowering women to reduce the risk of spina bifida in their children in the absence of population-wide food fortification.

  19. Motor learning in children with spina bifida: dissociation between performance level and acquisition rate.

    PubMed

    Edelstein, Kim; Dennis, Maureen; Copeland, Kim; Frederick, Jon; Francis, David; Hetherington, Ross; Brandt, Michael E; Fletcher, Jack M

    2004-10-01

    The cerebellum is part of a neural circuit involved in procedural motor learning. We examined how congenital cerebellar malformations affect mirror drawing performance, a procedural learning task that involves learning to trace the outline of a star while looking at the reflection of the star in a mirror. Participants were 88 children with spina bifida myelomeningocele, a neural tube defect that results in lesions of the spinal cord, dysmorphology of the cerebellum, and requires shunt treatment for hydrocephalus, and 35 typically developing controls. Participants completed 10 trials in the morning and 10 trials following a 3-hr delay. Although children with spina bifida myelomeningocele were initially slower at tracing and made more errors than controls, all participants improved their performance of the task, as demonstrated by increased speed and accuracy across trials. Moreover, degree of cerebellar dysmorphology was not correlated with level of performance, rate of acquisition, or retention of mirror drawing. The results suggest that congenital cerebellar dysmorphology in spina bifida does not impair motor skill learning as measured by acquisition and retention of the mirror drawing task.

  20. A snapshot of the adult spina bifida patient – high incidence of urologic procedures

    PubMed Central

    Liu, Joceline S.; Greiman, Alyssa; Casey, Jessica T.; Mukherjee, Shubhra

    2016-01-01

    Introduction To describe the urologic outcomes of contemporary adult spina bifida patients managed in a multidisciplinary clinic. Material and methods A retrospective chart review of patients seen in our adult spina bifida clinic from January 2004 to November 2011 was performed to identify urologic management, urologic surgeries, and co-morbidities. Results 225 patients were identified (57.8% female, 42.2% male). Current median age was 30 years (IQR 27, 36) with a median age at first visit of 25 years (IQR 22, 30). The majority (70.7%) utilized clean intermittent catheterization, and 111 patients (49.3%) were prescribed anticholinergic medications. 65.8% had urodynamics performed at least once, and 56% obtained appropriate upper tract imaging at least every other year while under our care. 101 patients (44.9%) underwent at least one urologic surgical procedure during their lifetime, with a total of 191 procedures being performed, of which stone procedures (n = 51, 26.7%) were the most common. Other common procedures included continence procedures (n = 35, 18.3%) and augmentation cystoplasty (n = 29, 15.2%). Only 3.6% had a documented diagnosis of chronic kidney disease and 0.9% with end-stage renal disease. Conclusions Most adult spina bifida patient continue on anticholinergic medications and clean intermittent catheterization. A large percentage of patients required urologic procedures in adulthood. Patients should be encouraged to utilize conservative and effective bladder management strategies to reduce their risk of renal compromise. PMID:27123330

  1. The prevalence and predictors of anencephaly and spina bifida in Texas.

    PubMed

    Canfield, Mark A; Marengo, Lisa; Ramadhani, Tunu A; Suarez, Lucina; Brender, Jean D; Scheuerle, Angela

    2009-01-01

    Texas shares a 1255-mile border with Mexico and encompasses a variety of ecosystems, industries and other potential environmental exposures. The Texas Birth Defects Registry is an active surveillance system which covers all pregnancy outcomes (livebirths, fetal deaths and elective pregnancy terminations). This study describes the occurrence and the predictors of neural tube defects (anencephaly and spina bifida) in Texas between 1999 and 2003. Birth prevalence, crude and adjusted prevalence ratios and 95% confidence intervals were calculated using Poisson regression, for each defect, by fetal/infant sex, delivery year and maternal sociodemographic characteristics. Among approximately 1.8 million livebirths, a total of 1157 neural tube defects cases were ascertained by the Registry, resulting in an overall prevalence of 6.33 cases per 10 000 livebirths. The prevalences of anencephaly and spina bifida were 2.81 and 3.52 per 10 000 livebirths respectively. Prevalences of both defects were highest in Hispanics, among mothers living along the border with Mexico, among women of higher parity and among mothers who were 40+ years of age. In addition, the prevalence of each defect was higher among women with no record of prenatal care and among women with less than 7 years of education. Hispanic ethnicity was an important predictor for anencephaly, along with sex, maternal age, parity and border residence. However, only border residence and delivery year were significant predictors for spina bifida.

  2. Self-concept in children with spina bifida compared with typically developing children.

    PubMed

    Shields, Nora; Taylor, Nicholas F; Dodd, Karen J

    2008-10-01

    The literature was systematically reviewed to determine if children with spina bifida have lower self-concept compared with their peers with typical development. Relevant trials were identified by searching electronic databases, supplemented by citation tracking. Of 803 papers initially identified, 15 met the inclusion criteria. Meta-analysis revealed children with spina bifida scored significantly lower than children with typical development for the domains of global self-worth (d=-0.39, 95% confidence interval [CI] -0.65 to -0.12); physical appearance (d=-0.26, 95% CI -0.46 to -0.06); athletic competence (d=-0.45, 95% CI -0.67 to -0.22); social acceptance (d=-0.33, 95% CI -0.55 to -0.11); and scholastic competence (d=-0.43, 95% CI -0.66 to -0.21). There was no difference between the groups for the behavioural conduct domain. Children with spina bifida on average have a lower self-concept than their peers with typical development. Clinicians need to take account of this information in planning the assessment and treatment of this group.

  3. Monte Carlo fundamentals

    SciTech Connect

    Brown, F.B.; Sutton, T.M.

    1996-02-01

    This report is composed of the lecture notes from the first half of a 32-hour graduate-level course on Monte Carlo methods offered at KAPL. These notes, prepared by two of the principle developers of KAPL`s RACER Monte Carlo code, cover the fundamental theory, concepts, and practices for Monte Carlo analysis. In particular, a thorough grounding in the basic fundamentals of Monte Carlo methods is presented, including random number generation, random sampling, the Monte Carlo approach to solving transport problems, computational geometry, collision physics, tallies, and eigenvalue calculations. Furthermore, modern computational algorithms for vector and parallel approaches to Monte Carlo calculations are covered in detail, including fundamental parallel and vector concepts, the event-based algorithm, master/slave schemes, parallel scaling laws, and portability issues.

  4. Neurological Outcomes after Human Umbilical Cord Patch for In Utero Spina Bifida Repair in a Sheep Model

    PubMed Central

    Papanna, Ramesha; Mann, Lovepreet K.; Snowise, Saul; Morales, Yisel; Prabhu, Sanjay P.; Tseng, Scheffer C. G.; Grill, Raymond; Fletcher, Stephen; Moise, Kenneth J.

    2016-01-01

    Objectives The objective of our study was to test the hypothesis that in utero repair of surgically created spina bifida in a sheep model using cryopreserved human umbilical cord (HUC) patch improves neurological outcome. Methods Spina bifida with myelotomy was surgically created in timed pregnant ewes at gestational day (GD) 75. The fetuses were randomly assigned to unrepaired versus HUC and treated at GD 95 and then delivered at GD 140. Neurological evaluation was performed using the Texas Spinal Cord Injury Scale (TSCIS), bladder control using ultrasound, and the hindbrain herniation. Results Three lambs without the spina bifida creation served as controls. There were four lambs with spina bifida: two were unrepaired and two underwent HUC repair. The control lambs had normal function. Both unrepaired lambs had nonhealed skin lesions with leakage of cerebrospinal fluid, a 0/20 TSCIS score, no bladder control, and the hindbrain herniation. In contrast, both HUC lambs had a completely healed skin defect and survived to day 2 of life, a 3/20 and 4/20 TSCIS score (nociception), partial bladder control, and normal hindbrain anatomy. Conclusions Cryopreserved HUC patch appears to improve survival and neurological outcome in this severe form of the ovine model of spina bifida. PMID:27621952

  5. EMG activities of the quadratus lumborum and erector spinae muscles during flexion-relaxation and other motor tasks.

    PubMed

    Andersson, E A; Oddsson, L I E; Grundström, H; Nilsson, J; Thorstensson, A

    1996-10-01

    OBJECTIVE: The aim of this study was to provide new information on the myoelectrical activation of the quadratus lumborum, the deep lateral and the superficial medial lumbar erector spinae, the psoas, and the iliacus muscles in various motor tasks. DESIGN: An intramuscular electromyographic study was performed. BACKGROUND: The contribution of individual deep trunk muscles to the stability of the lumbar spine is relatively unknown in different tasks, including the flexion-relaxation phenomenon. METHODS: Seven healthy subjects participated. Fine-wire electrodes were inserted with a needle guided by ultrasound. RESULTS: The highest activity observed for quadratus lumborum and deep lateral erector spinae occurred in ipsilateral trunk flexion in a side-lying position and for superficial medial erector spinae during bilateral leg lift in a prone position. Quadratus lumborum and deep lateral erector spinae were activated when the flexion-relaxation phenomenon was present for superficial medial erector spinae, i.e. when its activity ceased in the latter part of full forward flexion of the trunk, held relaxed and kyphotic. CONCLUSIONS: In general, the activation of the investigated muscles showed a high degree of task specificity, where activation of a certain muscle was not always predictable from its anatomical arrangement and mechanical advantage.

  6. Disturbed apoptosis and cell proliferation in developing neuroepithelium of lumbo-sacral neural tubes in retinoic acid-induced spina bifida aperta in rat.

    PubMed

    Wei, Xiaowei; Li, Hui; Miao, Jianing; Zhou, Fenghua; Liu, Bo; Wu, Di; Li, Shujing; Wang, Lili; Fan, Yang; Wang, Weilin; Yuan, Zhengwei

    2012-08-01

    Spina bifida is a complex congenital malformation resulting from failure of fusion in the spinal neural tube during embryogenesis. However, the cellular mechanism underlying spina bifida is not fully understood. Here, we investigated cell apoptosis in whole embryos and proliferation of neural progenitor cells in the spinal neural tube during neurulation in all-trans retinoic acid (atRA)-induced spina bifida in fetal rats. Cell apoptosis was assessed by TUNEL assay on whole-mount and serially sectioned samples of rat embryos with spina bifida. Cell proliferation of lumbo-sacral neural progenitor cells was assessed by staining for the mitotic marker Ki67 and pH3. We found an excess of apoptosis in the neuroepithelium of embryos with spina bifida, which became more marked as embryos progress from E11 to E13. Conversely, there was a reduction in cell proliferation in spina bifida embryos, with a progressively greater difference from controls with stage from E11 to 13. Thus, atRA-induced spina bifida in rat shows perturbed apoptosis and proliferation of neural progenitors in the lumbo-sacral spinal cord during embryonic development, which might contribute to the pathogenesis of spina bifida.

  7. Spina bifida and birth outcome before and after fortification of flour with iron and folic acid in Oman.

    PubMed

    Alasfoor, D; Elsayed, M K; Mohammed, A J

    2010-05-01

    This paper presents the trend of spina bifida and other neural tube defects in Oman after the nationwide implementation of folate supplementation of pregnant women in 1990 and the fortification of wheat flour with iron and folate in 1996. The annual incidence of spina bifida fluctuated from 2.34 to 4.03 per 1000 deliveries between 1991 and 1996, but fell sharply to 2.11 per 1000 deliveries in 1997, after which the downward trend continued, reaching 0.29 per 1000 deliveries by 2006. The rate of other neural tube defects remained almost constant. The reduction in spina bifida rates in Oman could be linked to the start of flour fortification but not the supplementation programme.

  8. How I Do It: Management of spina bifida in a hospital in The People's Republic of China

    PubMed Central

    Bao, Nan; Lazareff, Jorge

    2015-01-01

    We present our personal experience on patients with Spina Bifida. It is the result of having treated 1600 children for 12 years at Shanghai Children's Medical Center. We classify the cases on Spina Bifida Manifesta (myelomeningocele, myelocele, lypomyelomeningocele) or Spina Bifida Oculta (lipoma, dermal sinus and thickened filum terminale). For the former, we recommend surgery within 24–48 h after birth. For the latter we recommend preventive surgery months after birth. We acknowledge that the diameter of the spinal canal is a problem for large remnant lesions. In cases of myelomeningocele, we prefer to place the shunt and close the defect in the same procedure, it reduces the risks inherent to exposure to anesthesia, reduces hospital stay, and related costs. If there is a suspicious of infection, we do not place the shunt on the same procedure. The personal description of the preferred techniques for closure of the different defects is described. PMID:26236554

  9. Volcanic hazard assessment in the Phlegraean Fields: a contribution based on stratigraphic and historical data

    NASA Astrophysics Data System (ADS)

    Rosi, M.; Santacroce, R.

    1984-06-01

    Phenomena occurring since 1982 in the Phlegraean Fields, interpreted as precursors of a potential renewal of volcanic activity, have forced us to anticipate some conclusions of a volcanic-hazard study based on the reconstruction of past eruptions in the area, to serve as basis for civil defense preparedness plans. The eruptive history of the Phlegraean Fields suggests a progressive decrease with time in the strength of eruptive phenomena paralleling a migration of vents towards the center of the Phlegraean caldera. Studies concerning the volcanic risk zonation were therefore concentrated on activities during the last 4,500 years and two eruptions (Monte Nuovo and Agnano Monte Spina), that occurred in 1538 and 4,400 years B.P., respectively were selected as the «reference eruptions» from which possible eruption scenarios were drawn.

  10. Discontinuation of Antimicrobial Prophylaxis (AP) in Children With Spina Bifida: A Case Series Analysis

    PubMed Central

    Couloures, Kevin G; Anderson, Michael; Machiorlatti, Michael; Marsenic, Olivera; Opas, Lawrence

    2016-01-01

    Background Spina bifida increases the risk for urinary tract infections (UTI). Antimicrobial prophylaxis (AP) reduces symptomatic UTI’s but selects resistant organisms. Measures to ensure regular and complete emptying of the bladder combined with treatment of constipation reduce the risk for UTI. Objectives Demonstrate that close adherence to a catheterization regimen in children with spina bifida (Selective Treatment - ST) reduces the need for antimicrobial prophylaxis. Methods Case series analysis of pediatric spina bifida clinic patients where routine antimicrobial prophylaxis was replaced by clean-catch catheterization and daily bowel regimen (ST). Retrospective chart review of 67 children (mean entry age: 24 months, median age: 4 months; 32 Males, 35 Females) enrolled between 1986 - 2004. Mean follow-up was 128.6 months (range 3 - 257 months). Asymptomatic and symptomatic UTI incidences were noted on AP and ST protocols. Creatinine clearance at study entry and follow-up was calculated by the age appropriate method. A multivariable regression model with delta Glomerular Filtration Rate (GFR) as the dependent variable, independent sample t-test and Wilcoxon rank sum were performed with SAS v. 9.2. Results The mean number of infections while on AP was 8.7 (95% CI 5.72, 11.68) and was 1.0 on ST (95% CI 0.48, 1.43). 5 infections on the AP protocol required intravenous (IV) antibiotics due to resistance to oral therapy, but none on ST. Comparing change in GFR between both protocols (AP vs. ST) found a significant difference in the change of GFR by treatment protocol. Conclusions AP did not prevent UTIs and resulted in more resistant organisms requiring IV antibiotics. Discontinuing AP allowed the return of susceptibility to oral antimicrobials and significantly improved GFR in those children who had previously been on AP. Adherence to a catheterization regimen with prompt treatment of symptomatic UTI conserved renal function and prevented selection of resistant

  11. 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.

  12. 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

  13. Spina bifida and hypospadias: a non random association or an X-linked recessive condition?

    PubMed

    Martínez-Frías, M L

    1994-08-01

    Here we describe a statistically significant association between hypospadias and spina bifida. This association was identified through the Spanish Collaborative Study of Congenital Malformations (ECEMC), where the observed number of cases was greater (P < 0.0005) than expected just by chance among males. We also detected a pair of concordant twins who had monochorial monoamniotic placenta. To the best of our knowledge, this is the first report of this combination of defects, consequently it must be confirmed whether this statistic association is an entity.

  14. A unifying hypothesis for hydrocephalus, Chiari malformation, syringomyelia, anencephaly and spina bifida

    PubMed Central

    Williams, Helen

    2008-01-01

    This work is a modified version of the Casey Holter Memorial prize essay presented to the Society for Research into Hydrocephalus and Spina Bifida, June 29th 2007, Heidelberg, Germany. It describes the origin and consequences of the Chiari malformation, and proposes that hydrocephalus is caused by inadequate central nervous system (CNS) venous drainage. A new hypothesis regarding the pathogenesis, anencephaly and spina bifida is described. Any volume increase in the central nervous system can increase venous pressure. This occurs because veins are compressible and a CNS volume increase may result in reduced venous blood flow. This has the potential to cause progressive increase in cerebrospinal fluid (CSF) volume. Venous insufficiency may be caused by any disease that reduces space for venous volume. The flow of CSF has a beneficial effect on venous drainage. In health it moderates central nervous system pressure by moving between the head and spine. Conversely, obstruction to CSF flow causes localised pressure increases, which have an adverse effect on venous drainage. The Chiari malformation is associated with hindbrain herniation, which may be caused by low spinal pressure relative to cranial pressure. In these instances, there are hindbrain-related symptoms caused by cerebellar and brainstem compression. When spinal injury occurs as a result of a Chiari malformation, the primary pathology is posterior fossa hypoplasia, resulting in raised spinal pressure. The small posterior fossa prevents the flow of CSF from the spine to the head as blood enters the central nervous system during movement. Consequently, intermittent increases in spinal pressure caused by movement, result in injury to the spinal cord. It is proposed that posterior fossa hypoplasia, which has origins in fetal life, causes syringomyelia after birth and leads to damage to the spinal cord in spina bifida. It is proposed that hydrocephalus may occur as a result of posterior fossa hypoplasia, where

  15. Correlation between architectural variables and torque in the erector spinae muscle during maximal isometric contraction.

    PubMed

    Cuesta-Vargas, Antonio; González-Sánchez, Manuel

    2014-01-01

    This study analysed whether a significant relationship exists between the torque and muscle thickness and pennation angle of the erector spinae muscle during a maximal isometric lumbar extension with the lumbar spine in neutral position. This was a cross-sectional study in which 46 healthy adults performed three repetitions for 5 s of maximal isometric lumbar extension with rests of 90 s. During the lumbar extensions, bilateral ultrasound images of the erector spinae muscle (to measure pennation angle and muscle thickness) and torque were acquired. Reliability test analysis calculating the internal consistency (Cronbach's alpha) of the measure, correlation between pennation angle, muscle thickness and torque extensions were examined. Through a linear regression the contribution of each independent variable (muscle thickness and pennation angle) to the variation of the dependent variable (torque) was calculated. The results of the reliability test were: 0.976-0.979 (pennation angle), 0.980-0.980 (muscle thickness) and 0.994 (torque). The results show that pennation angle and muscle thickness were significantly related to each other with a range between 0.295 and 0.762. In addition, multiple regression analysis showed that the two variables considered in this study explained 68% of the variance in the torque. Pennation angle and muscle thickness have a moderate impact on the variance exerted on the torque during a maximal isometric lumbar extension with the lumbar spine in neutral position.

  16. Age-related parenting stress differences in mothers of children with spina bifida.

    PubMed

    Macias, Michelle M; Saylor, Conway F; Rowe, Brandy P; Bell, Nancy L

    2003-12-01

    This study examined whether ages of child and parent were risk factors for general parenting stress and disability-specific stress in families of children with spina bifida. Parents of 64 children with spina bifida completed the Parenting Stress Index-Short Form, Parents of Children with Disabilities Inventory, and measures of family support and resources. Scores of families with children under 6 years (preschool) versus 6- to 12-yr.-old children (school age) were compared, as were scores of mothers above or below Age 35. Parents of school-aged children reported significantly higher stress on the Concerns for the Child domain of the Parents of Children with Disabilities Inventory. Mothers over 35 tended to report higher stress in the Concerns for the Child and Medical/Legal Concerns domains of the Parents of Children with Disabilities Inventory. No associations with medical severity, socioeconomic status, family resources, or family support were detected. As the children age and disability-related differences become more apparent, the same level of functioning and severity of disability may be associated with additional parenting stress. Older mothers and those with school-age children may need more resources than current social support systems typically provide.

  17. Assistive Technology Use Among Adolescents and Young Adults With Spina Bifida

    PubMed Central

    Johnson, Kurt L.; Dudgeon, Brian; Kuehn, Carrie; Walker, William

    2007-01-01

    Objectives. We sought to determine the use of assistive technology among a population of individuals with spina bifida. Methods. We performed a descriptive analysis of individuals aged 13 to 27 years diagnosed with myelomeningocele (n=348) using data obtained from an existing database at Children’s Hospital and Regional Medical Center, Seattle, Washington. We summarized disease characteristics, utilization of assistive technology, community and self-care independence, and other variables. Results. Eighty-four percent of the respondents lived with at least 1 of their natural parents. Fifty-seven percent used wheelchairs, 35% used braces, and 23% used walking aids. Independent self-care was a common skill, but 72% reported limited participation in structured activities. Half were aged 18 years or older; of those, only 50% had completed high school and 71% were unemployed. Those aged younger than 18 years were all still in school (100%). Conclusions. Adolescents and young adults with spina bifida rely on assistive technology and specialized care routines to maintain their health. Assistive technology use for mobility is common; little is known about secondary complications associated with use of these technologies or the use of assistive technology to address learning disabilities and other societal barriers. Underutilization of assistive technology could delay successful transitions to independent living and community participation. PMID:17194874

  18. A known functional polymorphism (Ile120Val) of the human PCMT1 gene and risk of spina bifida.

    PubMed

    Zhu, Huiping; Yang, Wei; Lu, Wei; Zhang, Jing; Shaw, Gary M; Lammer, Edward J; Finnell, Richard H

    2006-01-01

    Folate binding protein 1 (Folr1) knockout mice with low maternal folate concentrations have been shown to be excellent animal models for human folate-responsive neural tube defects (NTDs). Previous studies using the Folr1 knockout mice revealed that maternal folate supplementation up-regulates the expression of the PCMT1 gene in Folr1 nullizygous neural tube tissue during neural tube closure. PCMT1 encodes the protein repair enzyme l-isoaspartate (d-aspartate) O-methyltransferase (PIMT) that converts abnormal d-aspartyl and l-isoaspartyl residues to the normal l-aspartyl form. PIMT is known to protect certain neural cells from Bax-induced apoptosis. Pcmt1-deficient mice present with abnormal AdoMet/AdoHcy homeostasis. We hypothesized that a known functional polymorphism (Ile120Val) in the human PCMT1 gene is associated with an increased risk of folate-responsive human NTDs. A case-control study was conducted to investigate a possible association between this polymorphism and risk of spina bifida. Compared to the Ile/Ile and Ile/Val genotypes, the homozygous Val/Val genotype showed decreased risk for spina bifida (adjusted odds ratio=0.6, 95% confidence interval: 0.4-0.9). Our results showed that the Ile120Val polymorphism of PCMT1 gene is a genetic modifier for the risk of spina bifida. Val/Val genotype was associated with a reduction in risk for spina bifida.

  19. Trajectories of Psychosocial Adjustment in Adolescents with Spina Bifida: A 6-Year, Four-Wave Longitudinal Follow-up

    ERIC Educational Resources Information Center

    Holmbeck, Grayson N.; DeLucia, Christian; Essner, Bonnie; Kelly, Lauren; Zebracki, Kathy; Friedman, Deborah; Jandasek, Barbara

    2010-01-01

    Objective: As a follow-up to an earlier cross-sectional study (Holmbeck et al., 2003), the current multimethod, multi-informant investigation examined individual growth in psychosocial adjustment across the adolescent transition in 2 samples: young adolescents with spina bifida (SB) and typically developing adolescents (N = 68 in both groups at…

  20. Family functioning in children and adolescents with spina bifida: an evidence-based review of research and interventions.

    PubMed

    Holmbeck, Grayson N; Greenley, Rachel Neff; Coakley, Rachael Millstein; Greco, Joshua; Hagstrom, Jennifer

    2006-06-01

    Research on the adjustment of families of children with spina bifida is reviewed, with a focus on delineating the impact of spina bifida on family functioning, the strengths and weaknesses of past research, and the needs for future evidence-based research on family interventions with this population. PsychINFO and MEDLINE literature searches were used to identify studies of family functioning and family-based interventions for children with spina bifida. Identified studies were empirically evaluated for the presence or absence of key methodological or analytic criteria. Thirty-two studies of family functioning were identified from 25 separate research groups; most studies displayed significant methodological limitations. No published studies of interventions to promote adaptive family functioning were identified. Methodologically sound, longitudinal, and theory-driven studies of family functioning are needed, as are randomized family-based intervention trials to promote adaptive functioning and better psychosocial outcomes in families of children with spina bifida. Specific recommendations for future work as well as clinical implications are noted.

  1. [Physical education for spina bifida children in special schools for the physically handicapped (primary school)].

    PubMed

    Strohkendl, H; Schüle, K

    1978-01-01

    With a rate of 0.5-1/1,000 of the total number of births in West Germany, spina bifida is next to cerebral paresis one of the most frequent congenital defects. Altogether, fifty places in special schools are needed per one million of inhabitants for spina bifida children. The loss of physical unctions is comparable to that in the case of paraplegia. The variety of medical and psychological problems makes the cooperation of highly different branches of study indispensible in a rehabilitation team (neurosurgeon, neuropediatrician, urologist, orthopaedist, pediatrician, educator, social worker, physical therapist). Each team member must be informed about the complete rehabilitation plan. These children's shortage of environmental experience is mainly due to their backwardness as regards motoric development, which cannot be recovered by means of individual physical therapy alone. On the other hand, additional, specifically selected and organised physical education makes possible the necessary mobility and social experiences. By giving the children exercises suitable for their ages it is hoped to achieve a late maturation and stabilization of the personality. In choosing the exercises it is first of all necessary to go back to the so-called fundamental activities like climbing, hanging by one's hands, sliding, pushing oneself up off the ground, swinging or throwing and catching, before going on to wheel-chair sports. Wheel-chair sport promises a varied selection for group exercises (games) and for everyday use. Using the wheel-chair as sports equipment, it is possible for persons with other types of locomotive handicaps to be integrated into the group. For physical education in special schools the pupils whould be arranged into groups according to their ability in order to keep the groups as homogenous and the children's chances as equal as possible. The most important teaching criteria are in this case: the creation of a happy atmosphere, a high degree of clarity, the

  2. Perception of strong-meter and weak-meter rhythms in children with spina bifida meningomyelocele.

    PubMed

    Hopyan, Talar; Schellenberg, E Glenn; Dennis, Maureen

    2009-07-01

    Neurodevelopmental disorders such as spina bifida meningomyelocele (SBM) are often associated with dysrhythmic movement. We studied rhythm discrimination in 21 children with SBM and in 21 age-matched controls, with the research question being whether both groups showed a strong-meter advantage whereby rhythm discrimination is better for rhythms with a strong-meter, in which onsets of longer intervals occurred on the beat, than those with a weak-meter, in which onsets of longer intervals occurred off the beat. Compared to controls, the SBM group was less able to discriminate strong-meter rhythms, although they performed comparably in discriminating weak-meter rhythms. The attenuated strong-meter advantage in children with SBM shows that their rhythm deficits occur at the level of both perception and action, and may represent a central processing disruption of the brain mechanisms for rhythm.

  3. 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.

  4. The impact of spina bifida on development across the first 3 years.

    PubMed

    Lomax-Bream, Laura E; Barnes, Marcia; Copeland, Kim; Taylor, Heather B; Landry, Susan H

    2007-01-01

    Early cognitive, motor, and language skills were evaluated in 165 children, 91 with Spina Bifida (SB) and 74 developing typically. Assessments were given at 5 time points (6, 12, 18, 24, and 36 months of age). Three latent growth curve models were conducted to evaluate the development of these early skills, with social economic status and etiology as predictors of growth. Lesion level and shunting effects were included for group comparison. Children with SB exhibited lower levels of functioning in all areas, with slower rates of growth in cognition and language, but more acceleration in growth of motor skills. The impact of lesion level and shunting significantly related to growth in cognition and motor skills but not in language.

  5. The renal axes in spina bifida: issues of confusion and fusion.

    PubMed

    Mandell, G A; Maloney, K; Sherman, N H; Filmer, B

    1996-01-01

    The occurrence of horseshoe kidneys in myelodysplasia has been suggested to be overestimated because of the concurrent prevalence of kyphotic spine in the spina bifida population. Pseudohorseshoe kidneys result from the actual medial migration and apposition of the lower renal poles in the deep fossa created by the gibbus deformity. The presence of a lumbosacral kyphosis, however, does not imply there is not a true horseshoe kidney. In our myelodysplasia population of 189 patients, occurrence of true horseshoe kidneys (13 patients) and pseudohorseshoe kidneys (14 patients) was increased. The finding of lumbosacral kyphosis was twice as common in the pseudohorseshoe population as in the true horseshoe population. True horseshoe kidneys were three times more commonly seen in association with congenital vertebral anomalies cephalad to the dysraphic spine. Diagnosis in this study was predominantly based on renal cortical scintigraphy with the posterior pin-hole magnification technique.

  6. 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

  7. Barriers to community participation: Teens and young adults with spina bifida.

    PubMed

    Boudos, Rebecca Marie; Mukherjee, Shubhra

    2008-01-01

    This study identified the baseline participation rates for 101 teens and young adults ages 10-32 years old with a diagnosis of spina or lipomenigocele bifida in various domains: school, employment, community activities, physical activity and peer social relationships. The goal of the study was also to identify barriers to community participation. Our findings demonstrate that overall participation is low in several domains. Community participation is low with only 30% partaking in an organized community activity at least once a week. Multiple individual, family, and environmental barriers were identified by participants and their family. The most frequent barriers identified were low motivation (38%), lack of information (25%) and time constraints (21%). Barriers need to be addressed on an individualized basis as well as addressing the community as a whole. Future plans are to intervene based on the barriers and reassess participation at 6 months and a year with the goal of increased long term participation, employment, quality of life and social relationships.

  8. May spina bifida result from an X-linked defect in a selective abortion mechanism?

    PubMed Central

    Burn, J; Gibbens, D

    1979-01-01

    It is suggested that the major genetic factor in determining the birth of children with neural tube defects may be a single X-linked gene. It acts as an X-linked dominant, not by producing neural tube defects, but by enabling the affected fetus to survive selective spontaneous abortion. This mechanism, mediated at the deciduoplacental junction, may be under the control of both maternal and fetal genes. With more mutant alleles, survival would become more likely, reaching a maximum in the homozygous affected female fetus of a homozygous affected mother. The female excess in anancephaly is greater than that in spina bifida because of its prenatal severity, thus requiring relatively more mutant alleles for survival. PMID:381663

  9. Physiatrists and developmental pediatricians working together to improve outcomes in children with spina bifida.

    PubMed

    Swanson, Mark E; Dicianno, Brad E

    2010-08-01

    Based on the experience of 2 physicians from physiatry and developmental pediatrics, this article proposes a framework for improving care and outcomes for children with spina bifida. The combined skills of physiatrists and developmental pediatricians, along with other disciplines, can form the ideal team to manage the complex issues faced by this population. The developmental pediatrician is best suited for directing care for younger children through the elementary and middle school years, during which time behavioral and educational issues are prominent. As the child assumes more responsibility for self-management in adolescence, the physiatrist is ideally suited to provide major clinical input that improves functional outcomes. The addition of the discipline of physiatry to traditional, developmentally oriented pediatric interdisciplinary teams can add the much needed dimensions of activity and participation, and improve functional outcomes at the adult level by encouraging activities in adolescence that lead to full participation in adulthood.

  10. Perception of strong-meter and weak-meter rhythms in children with spina bifida meningomyelocele

    PubMed Central

    HOPYAN, TALAR; SCHELLENBERG, E. GLENN; DENNIS, MAUREEN

    2011-01-01

    Neurodevelopmental disorders such as spina bifida meningomyelocele (SBM) are often associated with dysrhythmic movement. We studied rhythm discrimination in 21 children with SBM and in 21 age-matched controls, with the research question being whether both groups showed a strong-meter advantage whereby rhythm discrimination is better for rhythms with a strong-meter, in which onsets of longer intervals occurred on the beat, than those with a weak-meter, in which onsets of longer intervals occurred off the beat. Compared to controls, the SBM group was less able to discriminate strong-meter rhythms, although they performed comparably in discriminating weak-meter rhythms. The attenuated strong-meter advantage in children with SBM shows that their rhythm deficits occur at the level of both perception and action, and may represent a central processing disruption of the brain mechanisms for rhythm. PMID:19573270

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

    SciTech Connect

    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 of the developmental and behavioral manifestations associated in the fragile X syndrome, while in others, it has no effect. 9 refs.

  12. Health professional expectations for self-care skill development in youth with spina bifida.

    PubMed

    Greenley, Rachel Neff

    2010-01-01

    The author examined expectations for the development of self-care skills for youth with spina bifida (SB) among a multidisciplinary group of health professionals, including physicians, nurse practitioners, nurses, and other professionals. Ninety-seven professionals from U.S. SB clinics completed a Web-based survey of expectations for youth attainment of bowel, bladder, and skin care skills. Professionals rated expectations for two hypothetical vignettes: a child with moderate SB severity and a child with greater severity. Most professionals believed that all skills were attainable by the end of elementary school in the moderate severity condition. Expectations for skill attainment in the severe condition were lower and significantly later (end of high school) than in the moderate condition. Professionals who treated more patients annually expected earlier bowel and bladder skill attainment. Findings highlight the importance of developing different timelines for nursing education of youth with moderate versus more severe condition impairment.

  13. Urinary Tract Infection Caused by Citrobacter koseri in a Patient With Spina Bifida, an Ileal Conduit and Renal Caluli Progressing to Peri-nephric Abscess and Empyema.

    PubMed

    Stewart, Zachary E; Shaker, Mohammed; Baxter, J David

    2017-02-01

    Urological problems are common in spina bifida and are often treated with urinary diversions. Spina bifida and ileal conduits put patients at increased risk for ascending urinary tract infections. Here we present a novel case of a Citrobacter koseri urinary tract infection complicated by a perinephric abscess with pleural extension. To our knowledge, no case of an ascending C. koseri UTI progressing to peri-nephric abscess and empyema by direct extension exists in the literature.

  14. Screening for Fetal Spina Bifida Aperta by the Ultrasound and Intracranial Translucency Examinations at 11-13(+6) Weeks of Gestation.

    PubMed

    Liu, Min; Liu, Ying; Li, Zhi-Hong; Yu, Ding

    2015-06-01

    The objective of the study is to evaluate the clinical significance of screening for fetal spina bifida aperta by ultrasound examination and intracranial translucency (IT) measurement at 11-13(+6) weeks of gestation. About 1,479 women at 11-13(+6) weeks of gestation in our hospital in 2012 were included as observation group, and 1,608 women at 11-13(+6) weeks of gestation without IT measurement in 2011 was included as controls. Detection rates of fetal spina bifida aperta in two groups were compared. The translucency thickness between the brain stem and choroid plexus and crown-rump length (CRL) in mid-sagittal view of the fetal face was measured, and translucency thickness and CRL in fetuses with spina bifida and healthy ones were compared. Detection rate of fetal spina bifida aperta in observation group was significantly higher than that in control group (six cases in observation group and one case in control group, p = 0.046). IT thickness was significantly lower in fetuses with spina bifida aperta (0.01 ± 1.25 mm) than that in healthy ones (1.73 ± 0.32 mm) (p < 0.001). There was positive correlation in healthy fetuses between IT thickness and CRL (r = 0.702, p < 0.001), but not in fetuses with spina bifida aperta (r = 0.001, p = 0.081). Ultrasound examination with IT measurement at 11-13(+6) weeks of gestation can be used to screen for fetal spina bifida aperta, and the reduction of IT thickness is an indicator of spina bifida aperta.

  15. Fetal Surgery: The Ochsner Experience with In Utero Spina Bifida Repair

    PubMed Central

    Kahn, Lora; Mbabuike, Nnenna; Valle-Giler, Edison P.; Garces, Juanita; Moore, R. Clifton; Hilaire, Hugo St.; Bui, Cuong J.

    2014-01-01

    Background Myelomeningocele is the most common form of congenital central nervous system defect that is compatible with life. Most patients with myelomeningocele have significant functional impairment of ambulation and bowel and bladder function, require permanent cerebrospinal fluid diversion with shunting, and have significant morbidity and mortality from hindbrain herniation (Chiari II malformation). The advent of intrauterine surgery has provided new opportunities to better address this lifelong debilitating disease. Case Report The patient was a 19-year-old gravida 2 para 1 at 22-6/7 weeks whose fetus was diagnosed with an open neural tube defect and further demonstrated to have ventriculomegaly and hindbrain herniation. Amniocentesis confirmed normal karyotype and the presence of acetylcholinesterase. After an intrauterine procedure, the patient underwent cesarean section at 35-5/7 weeks and delivered a male infant. His spinal incision was well healed at birth without any evidence of cerebrospinal fluid leakage, and his extremities were normal in appearance, range of motion, and movement. The infant also has maintained relatively normal, age-appropriate bowel and bladder function and has no obvious neurologic deficit. Conclusion As the benefit of fetal surgery becomes more widely accepted, quality of care and patient safety must be at the forefront of any institution's effort to offer fetal surgery. Given the current prevalence of spina bifida and the amount of resources required to treat this disease effectively either in utero or postnatally, it is our opinion that the treatment of spina bifida should be regionalized to tertiary referral centers with the interdisciplinary expertise to offer comprehensive treatment for all aspects of the disease and all phases of care for the patients. PMID:24688343

  16. 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.

  17. Assessment on self-care, mobility and social function of children with spina bifida in Turkey

    PubMed Central

    Sirzai, Hulya; Dogu, Beril; Demir, Selamet; Yilmaz, Figen; Kuran, Banu

    2014-01-01

    The aim of the study was to investigate the functional performance in children with spina bifida, using the Pediatric Evaluation of Disability Inventory (PEDI) to look into capacity of twenty-eight children with spina bifida with lesions at different levels in different dimensions of self-care, mobility and social function. Mean age of the patients was 3.5 ± 2.3 (1–10) years. In the muscle test carried out, 13 patients (44.8%) had no movements including pelvic elevation in lower extremity muscles and they were at level 5. Sixteen patients (54%) were non-ambulatory according to the Hoofer ambulation classification. Raw and scale scores in the self-care, mobility and social function domains both in the functional skill scale and in the caregiver scale were found to be lower compared to the data of the normal population. A statistically significant correlation was observed in the self-care values of the Functional Skills Scales and the Caregiver Assistance Scale measurements, which was positive for age and negative for Functional Ambulation Scale and muscle test (P < 0.05). A positive relation was found between the Functional Skills Scales-mobility area and age while a negative relation was observed between Functional Ambulation Scale and muscle test (P < 0.005). A negative relation was also found between Caregiver Assistance Scale-mobility and Functional Ambulation Scale and muscle test (P < 0.005). In our study, the functional performance of the children was found to be low. Low-level lesions, encouraging muscular strength and independence in mobility are all very important factors for functional independence. PMID:25206788

  18. Spina Bifida

    MedlinePlus

    ... spine, or spinal cord. It happens if the spinal column of the fetus doesn't close completely during the first month of pregnancy. This can damage the nerves and spinal cord. Screening tests during pregnancy can check for ...

  19. Spina Bifida

    MedlinePlus

    ... Strategy Current Research Research Funded by NINDS Basic Neuroscience Clinical Research Translational Research Research at NINDS Focus ... Information Current Research Research Funded by NINDS Basic Neuroscience Clinical Research Translational Research Research at NINDS Focus ...

  20. Detection of Spina Bifida by First Trimester Screening - Results of the Prospective Multicenter Berlin IT-Study.

    PubMed

    Chen, Frank Chih-Kang; Gerhardt, Janine; Entezami, Michael; Chaoui, Rabih; Henrich, Wolfgang

    2017-04-01

    Purpose To evaluate the potential of routine assessment of intracranial translucency (IT) and other posterior brain parameters in the early detection of open spina bifida during the 11 - 14 weeks screening examination. Materials and Methods This prospective, multicenter longitudinal study was conducted with the participation of 20 certified DEGUM II or III experts in Berlin, Germany, between June 2010 and October 2013. All pregnant women undergoing a first trimester screening were included in the study and in every patient were the IT, brain stem (BS), cisterna magna (CM), BS to occipital bone distance (BSOB) and BS/BSOB ratio measured. All patients with continuing pregnancy underwent a second trimester scan. Our data was used to develop our own reference ranges. The primary outcome parameter was the presence of open spina bifida. Results A total of 15 526 women with 16 164 fetuses were examined. Median of the IT was 2.1 mm, of the CM 1.6 mm, of the BS 2.7 mm, of the BSOB 5.5 mm, and of the BS/BSOB ratio 0.49. There were 11 cases with open spina bifida (incidence of 6.8/10 000). The detection rate was 100 % and in all cases of spina bifida, the anomaly was detected either at the first examination (n = 8) or considered suspicious and the lesion then detected a few weeks later (n = 3). Considering individual measurements, however, the detection rate was 18 % with the complete absence of the IT and 45 % with cut-off values. For the CM measurement, the detection rate was 64 % with the absence of the CM and 73 % with cut-off values. The other parameters proved not to be predictive of open spina bifida. Conclusion In the hands of an expert, open spina bifida can be reliably diagnosed early in gestation during the 11 - 14 weeks screening. The measurement of different parameters of the posterior brain, especially the CM and the use of cut-off values are of tremendous benefit in achieving a high sensitivity in the detection

  1. Monte Carlo Reliability Analysis.

    DTIC Science & Technology

    1987-10-01

    to Stochastic Processes , Prentice-Hall, Englewood Cliffs, NJ, 1975. (5) R. E. Barlow and F. Proscham, Statistical TheorX of Reliability and Life...Lewis and Z. Tu, "Monte Carlo Reliability Modeling by Inhomogeneous ,Markov Processes, Reliab. Engr. 16, 277-296 (1986). (4) E. Cinlar, Introduction

  2. Tephrostratigraphy study for the last 18,000 14C years in a deep-sea sediment sequence for the South Adriatic

    NASA Astrophysics Data System (ADS)

    Siani, Giuseppe; Sulpizio, Roberto; Paterne, Martine; Sbrana, Alessandro

    2004-12-01

    A detailed tephrostratigraphy supported by accelerator mass spectrometry (AMS) 14C dating and isotopic and geochemical analyses has been carried out for a deep-sea core collected from the Southern Adriatic Sea, which spans the last 18 14C kyr. Fourteen ash layers have been recognized in the marine core and the origin was determined by comparing their age and geochemistry with tephra detected in terrestrial deposits. The geochemical signatures of marine ash layers indicate a prevailing Campanian and subordinate Etnean and Eolian provenances. Collectively, they are attributed to sources in the Phlegraean Fields (LAM-Lagno Amendolare; LN1/LN2-GM1; C-2/NYT-Neapolitan Yellow Tuff; C-1-Agnano Pomici Principali; AMS/PF-Agnano Monte Spina; AST-Astroni), Somma-Vesuvius (L9-Pomici di Base; L8-Greenish), Mount Etna (Et1-Y1-Biancavilla Ignimbrite), Lipari (E-1-Gabellotto-Fiumebianco) and Palinuro seamount (Pal 1). Some of these eruptions have been detected for the first time in marine cores (Astroni, LAM, L9, L8), and three were detected and dated by marine tephra (LN1, LN2, and Pal 1) providing new more precise stratigraphic markers for the last 18 kyr in the South Adriatic marine record.

  3. The Somma-Vesuvius complex and the Phlaegrean Fields caldera: New chronological data of several eruptions of the Copper-Middle Bronze Age period

    NASA Astrophysics Data System (ADS)

    Passariello, Isabella; Lubritto, Carmine; D'Onofrio, Antonio; Guan, Yongjing; Terrasi, Filippo

    2010-04-01

    Radiocarbon dating of short-lived sample materials is a useful tool applied to date deposits of volcanic eruptions. Several archaeological sites discovered and excavated in Campania witnessed important volcanic eruptions, which occurred in the Copper and Middle Bronze Ages. These eruptions come from the Somma-Vesuvius complex and the Phlaegrean Fields caldera. At least four Plinian eruptions have been identified in the eruptive history of Somma-Vesuvius, interspersed by interplinian events, called protohistoric, which occurred between Avellino and Pompeii. At S. Paolo Belsito a stratigraphic sequence below Avellino and above the first two protohistoric events after Avellino were highlighted; while Nola (Naples) gives new information on the chronology of Avellino. Sites like Caivano and Gricignano D'Aversa, involved by the Agnano 3, Paleoastroni 2 and Agnano Monte Spina eruptions were highlighted and investigated. In this work, we want to clarify the chronology of some eruptions by comparing our results with previous data. Charcoal, bone and seed samples were collected, treated and measured at the CIRCE laboratory in Caserta.

  4. A systematic review of the risks factors associated with the onset and natural progression of spina bifida.

    PubMed

    Donnan, Jennifer; Walsh, Stephanie; Sikora, Lindsey; Morrissey, Andrea; Collins, Kayla; MacDonald, Don

    2016-03-19

    The purpose of this study was to systematically assess and synthesize the world literature on risk factors for the onset and natural progression of spina bifida, thereby providing a basis for policy makers to identify appropriate risk management measures to mitigate the burden of disease in Canada. Searches of several health literature databases from inception to February 2013 were conducted by a health sciences librarian. A total of three meta-analyses that studied a risk factor for the onset of spina bifida were included. Pooled results showed that paternal exposure to Agent Orange (RR=2.02; 95% CI 1.48-2.74) and maternal obesity prior to pregnancy (OR=2.24; 95% CI 1.86-2.74) each increased the risk of having a child with spina bifida. Paternal exposure to organic solvents was also close to the limit of significance (OR=1.59; 95% CI 0.99-2.56). A total of 63 observational studies, encompassing hundreds of potential risk factors, were included for risk factors for the onset of disease. One meta-analysis and four observational studies examined the impact of genetic risk factors. Only specified mutations in the 5,10-methylenetetrahydrofolate reductase (MTHFR) and dihydrofolate reductase (DHFR) genes were found to be linked to disease onset. One observational study evaluated a risk factor for the natural progression of disease. An extensive number of potential risk factors for the onset of spina bifida have been studied, though most lack sufficient evidence to confirm an association. Currently, strong evidence exists to suggest a causal association for maternal obesity prior to pregnancy, and paternal exposure to Agent Orange.

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

    PubMed Central

    Wynd, Andrew HD; Carachi, Robert

    2014-01-01

    Background and Aims 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. Methods and Results 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. Conclusion 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. PMID:25358489

  6. Fundamentals of Monte Carlo

    SciTech Connect

    Wollaber, Allan Benton

    2016-06-16

    This is a powerpoint presentation which serves as lecture material for the Parallel Computing summer school. It goes over the fundamentals of the Monte Carlo calculation method. The material is presented according to the following outline: Introduction (background, a simple example: estimating π), Why does this even work? (The Law of Large Numbers, The Central Limit Theorem), How to sample (inverse transform sampling, rejection), and An example from particle transport.

  7. Monte Carlo eikonal scattering

    NASA Astrophysics Data System (ADS)

    Gibbs, W. R.; Dedonder, J. P.

    2012-08-01

    Background: The eikonal approximation is commonly used to calculate heavy-ion elastic scattering. However, the full evaluation has only been done (without the use of Monte Carlo techniques or additional approximations) for α-α scattering.Purpose: Develop, improve, and test the Monte Carlo eikonal method for elastic scattering over a wide range of nuclei, energies, and angles.Method: Monte Carlo evaluation is used to calculate heavy-ion elastic scattering for heavy nuclei including the center-of-mass correction introduced in this paper and the Coulomb interaction in terms of a partial-wave expansion. A technique for the efficient expansion of the Glauber amplitude in partial waves is developed.Results: Angular distributions are presented for a number of nuclear pairs over a wide energy range using nucleon-nucleon scattering parameters taken from phase-shift analyses and densities from independent sources. We present the first calculations of the Glauber amplitude, without further approximation, and with realistic densities for nuclei heavier than helium. These densities respect the center-of-mass constraints. The Coulomb interaction is included in these calculations.Conclusion: The center-of-mass and Coulomb corrections are essential. Angular distributions can be predicted only up to certain critical angles which vary with the nuclear pairs and the energy, but we point out that all critical angles correspond to a momentum transfer near 1 fm-1.

  8. Maternal periconceptional vitamin use, genetic variation of infant reduced folate carrier (A80G), and risk of spina bifida.

    PubMed

    Shaw, Gary M; Lammer, Edward J; Zhu, Huiping; Baker, Mei Wang; Neri, Eric; Finnell, Richard H

    2002-02-15

    Women who consume folic acid in early pregnancy reduced their risks for delivering offspring with neural tube defects (NTDs). The underlying process by which folic acid facilitated this risk reduction is unknown. Investigating genetic variation that influences cellular absorption, transport, and metabolism of folate will help fill this data gap. We focused our studies on a candidate gene that is involved in folate transport, the reduced folate carrier 1 (RFC1). Using data from a California population-based case control interview study (1989-1991 birth cohorts), we investigated whether spina bifida risk was influenced by an interaction between a polymorphism of infant RFC1 at nucleotide 80 (A80G) and maternal periconceptional use of vitamins containing folic acid. Allelic variants of RFC1 were determined by genotyping 133 live-born spina bifida case infants and 188 control infants. The percentages of case infants with the A80/A80, G80/G80, and G80/A80 genotypes were 27.2%, 28.0%, and 44.7%, respectively. The percentages of control infants were similar: 26.1%, 29.3%, and 44.7%. Odds ratios of 1.0 (95% confidence interval 0.5-2.0) for the G80/G80 genotype and 1.1 (0.6-2.0) for the G80/A80 genotype were observed relative to the A80/A80 genotype. Among mothers who did not use vitamins, spina bifida risk was 2.4 (0.8-6.9) for infants with genotype G80/G80 compared to those with A80/A80 genotype. Among mothers who did use vitamins, the risk was 0.5 (0.1-3.1) for infants with the G80/G80 genotype. Although this study did not find an increased spina bifida risk for infants who were heterozygous or homozygous for RFC1 A80G, it did reveal modest evidence for a gene-nutrient interaction between infant homozygosity for the RFC1 G80/G80 genotype and maternal periconceptional intake of vitamins containing folic acid on the risk of spina bifida.

  9. Transgenic studies on homeobox genes in nervous system development: spina bifida in Isl1 transgenic mice.

    PubMed

    Kappen, Claudia; Yaworsky, Paul J; Muller, Yunhua L; Salbaum, J Michael

    2013-04-01

    To develop in vivo assays for homeobox gene function in neural development, we generated transgenic mice in which the expression of a homeobox gene is altered only within the nervous system, in neurons or neuronal precursor cells. Transgenic expression of Hoxc8 did not result in gross abnormalities, while a Hoxd4 transgene caused death shortly after birth. In neural progenitor cells, the motorneuron-specific homeodomain transcription factor Isl1 induced early developmental defects, including absence of anterior neural structures, profound defects in the neuroepithelium and defective neural tube closure. A fraction of Isl1 transgenic mice exhibited spina bifida. Isl1 transgene expression was also associated with decreased proliferation and increased Pbx1 expression in the ventral neural tube. Our results suggest a function for some homeobox genes in development of the nervous system, and that cell-type- and region-specific transgenic models will be useful to identify the cellular and molecular targets of homeobox transcription factors in nervous system development.

  10. 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.

  11. Anomalous development of brain structure and function in spina bifida myelomeningocele

    PubMed Central

    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 malformation. Other structural anomalies are not necessarily unique to SBM, including altered development of the corpus callosum and posterior fossa. Within SBM, tremendous heterogeneity is reflected in the degree to which brain structures are atypical in qualitative appearance and quantitative measures of morphometry. Hallmark structural features of SBM include overall reductions in posterior fossa and cerebellum appearance, size, and volume. Studies of the corpus callosum have shown complex patterns of agenesis or hypoplasia along its rostral-caudal axis, with rostrum and splenium regions particularly susceptible to agenesis. Studies of cortical regions have demonstrated complex patterns of thickening, thinning, and gyrification. Diffusion tensor imaging studies have reported compromised integrity of some specific white matter pathways. Given equally complex ocular motor, motor, and cognitive phenotypes consisting of relative strengths and weaknesses that seem to align with altered structural development, studies of SBM provide new insights to our current understanding of brain structure-function associations. PMID:20419768

  12. The Influence of Condition Parameters and Internalizing Symptoms on Social Outcomes in Youth With Spina Bifida

    PubMed Central

    Essner, Bonnie S.; Murray, Caitlin B.

    2014-01-01

    Objective To test a model of social competence in youth with spina bifida (SB). Involvement in social activities was expected to mediate associations between SB-related condition parameters (pain, body mass index, and motor function) and social competence. Internalizing symptoms were predicted to amplify the negative impact of condition parameters on social activity involvement. Methods 108 youth with SB, their caregivers, peers, and teachers participated in a multimethod study that included cognitive testing, questionnaires, and observational interaction tasks. Results Social activity involvement partially mediated the relation between pain and lower social competence. Internalizing symptoms had a significant indirect effect on social competence via decreased involvement in social activities. Conclusions Pain and internalizing symptoms interfere with social activity involvement, which is, in turn, important for social competence development in youth with SB. Assessing and treating these condition parameters and activity factors may be important areas of focus in clinical practice and research with these youth. PMID:24914086

  13. Object-based and action-based visual perception in children with spina bifida and hydrocephalus.

    PubMed

    Dennis, Maureen; Fletcher, Jack M; Rogers, Tracey; Hetherington, Ross; Francis, David J

    2002-01-01

    Children with spina bifida and hydrocephalus (SBH) have long been known to have difficulties with visual perception. We studied how children with SBH perform 12 visual perception tasks requiring object identification, multistable representations of visual space, or visually guided overt actions. Four tasks required object-based processing (visual constancy illusions, face recognition, recognition of fragmented objects, line orientation). Four tasks required the representation of visual space in egocentric coordinates (stereopsis, visual figure-ground identification, perception of multistable figures, egocentric mental rotation). Four tasks required the coupling of visual space to overt movement (visual pursuit, figure drawing, visually guided route finding, visually guided route planning). Effect sizes, measuring the magnitude of the difference between SBH children and controls, were consistently larger for action-based than object-based visual perception tasks. Within action-based tasks, effect sizes were large and roughly comparable for tasks requiring the representation of visual space and for tasks requiring visually guided action. The results are discussed in terms of the physical and brain problems of children with SBH that limit their ability to build effective situation models of space.

  14. Attention in spina bifida myelomeningocele: Relations with brain volume and integrity.

    PubMed

    Kulesz, Paulina A; Treble-Barna, Amery; Williams, Victoria J; Juranek, Jenifer; Cirino, Paul T; Dennis, Maureen; Fletcher, Jack M

    2015-01-01

    This study investigated the relations of tectal volume and superior parietal cortex, as well as alterations in tectocortical white matter connectivity, with the orienting and executive control attention networks in individuals with spina bifida myelomeningocele (SBM). Probabilistic diffusion tractography and quantification of tectal and superior parietal cortical volume were performed on 74 individuals aged 8-29 with SBM and a history of hydrocephalus. Behavioral assessments measured posterior (covert orienting) and anterior (conflict resolution, attentional control) attention network functions. Reduced tectal volume was associated with slower covert orienting; reduced superior parietal cortical volume was associated with slower conflict resolution; and increased axial diffusivity and radial diffusivity along both frontal and parietal tectocortical pathways were associated with reduced attentional control. Results suggest that components of both the orienting and executive control attention networks are impaired in SBM. Neuroanatomical disruption to the orienting network appears more robust and a direct consequence of characteristic midbrain dysmorphology; whereas, executive control difficulties may emerge from parietal cortical anomalies and reduced frontal and parietal cortical-subcortical white matter pathways susceptible to the pathophysiological effects of congenital hydrocephalus.

  15. “Slow walking with turns” increases quadriceps and erector spinae muscle activity

    PubMed Central

    Araki, Mayumi; Hatamoto, Yoichi; Higaki, Yasuki; Tanaka, Hiroaki

    2017-01-01

    [Purpose] To maintain an independent lifestyle, older adults should improve muscle strength and mass, or aerobic capacity. A new exercise pattern, called slow walking with turns, which incorporates turning as an extra load additional to walking. The purpose of this study was to measure oxygen consumption during exercise and muscle activity while turning. [Subjects and Methods] Recreationally active volunteers participated. The participants performed 20 turns per minute while walking back and forth over distances of 1.5 to 3.5 m. We measured oxygen consumption, heart rate, and rating of perceived exertion and performed electromyography during the exercise. [Results] The metabolic equivalents of the exercise were 4.0 ± 0.4 to 6.3 ± 4.0 Mets. Activity was significantly greater in the vastus medialis, vastus lateralis, and erector spinae during the turn phase of slow walking with turns than during the stance phase of treadmill walking. [Conclusion] These findings suggest that slow walking with turns may help to preserve the muscle strength and mass of the trunk and lower limbs that are needed to maintain an independent lifestyle. Slow walking can be performed easily by older people, and in slow walking with turns, the exercise intensity can be adjusted as required for each individual. PMID:28356623

  16. Physical fitness and exercise training on individuals with spina bifida: a systematic review.

    PubMed

    Oliveira, Ana; Jácome, Cristina; Marques, Alda

    2014-05-01

    Spina Bifida (SB) is characterized by several physical impairments; however, data on physical fitness and on the benefits of exercise training in individuals with SB are dispersed in the literature. Thus, this systematic review aimed to describe (i) physical fitness components (cardiorespiratory endurance, muscle strength, body composition, flexibility and neuromotor) and (ii) exercise training effects on the physical fitness of individuals with SB. CINAHL, MEDLINE and EMBASE were searched from January to March 2013 and updated in December 2013. Twenty-three studies were included. A summary of the results was performed using a best-evidence synthesis. Participants with SB had lower cardiorespiratory endurance (-32 to 54% in VO2 peak) and muscle strength (-58 to 90%) and higher body fat (159%) than their healthy peers. Mobility restrictions were present in 26.3-61% of participants. No data on neuromotor fitness were found. Aerobic and strength training improved participants' cardiorespiratory endurance (effect sizes 0.78-1.4) and muscle strength (effect sizes 0-0.59). Individuals with SB have impaired cardiorespiratory endurance, muscle strength, body composition and flexibility when compared to healthy peers. Exercise training seems to improve two of these fitness components (cardiorespiratory endurance and muscle strength). Nevertheless, the heterogeneity of the studies' designs, methods and instruments used limits the establishment of firm conclusions and highlights the need for further research.

  17. White and grey matter relations to simple, choice, and cognitive reaction time in spina bifida.

    PubMed

    Dennis, Maureen; Cirino, Paul T; Simic, Nevena; Juranek, Jenifer; Taylor, W Pat; Fletcher, Jack M

    2016-03-01

    Elevated reaction time (RT) is common in brain disorders. We studied three forms of RT in a neurodevelopmental disorder, spina bifida myelomeningocele (SBM), characterized by regional alterations of both white and grey matter, and typically developing individuals aged 8 to 48 years, in order to establish the nature of the lifespan-relations of RT and brain variables. Cognitive accuracy and RT speed and variability were all impaired in SBM relative to the typically developing group, but the most important effects of SBM on RT are seen on tasks that require a cognitive decision rule. Individuals with SBM are impaired not only in speeded performance, but also in the consistency of their performance on tasks that extend over time, which may contribute to poor performance on a range of cognitive tasks. The group with SBM showed smaller corrected corpus callosum proportions, larger corrected cerebellar white matter proportions, and larger corrected proportions for grey matter in the Central Executive and Salience networks. There were clear negative relations between RT measures and corpus callosum, Central Executive, and Default Mode networks in the group with SBM; relations were not observed in typically developing age peers. Statistical mediation analyses indicated that corpus callosum and Central Executive Network were important mediators. While RT is known to rely heavily on white matter under conditions of typical development and in individuals with adult-onset brain injury, we add the new information that additional involvement of grey matter may be important for a key neuropsychological function in a common neurodevelopmental disorder.

  18. Associations of Ethnicity and SES with IQ and Achievement in Spina Bifida Meningomyelocele

    PubMed Central

    Garnaat, Sarah L.; Myszka, Katherine A.; Fletcher, Jack M.; Dennis, Maureen

    2010-01-01

    Objectives We evaluated whether the phenotypic pattern of higher verbal than nonverbal IQ in children with spina bifida meningomyelocele (SBM) is consistent across subgroups differing in ethnicity and SES. We also explored the relation of cognitive and academic performance. Methods Non-Hispanic White (n = 153) and Hispanic (n = 80) children with SBM received the Stanford Binet Test of Intelligence-IV and achievement subtests of the Woodcock–Johnson. Parents completed questionnaires assessing the family environment [socioeconomic status (SES), resources, and educational opportunities]. Results Multivariate analysis revealed that Hispanic children with lower SES had lower verbal than nonverbal scores. Hispanic children with higher SES and non-Hispanic White children demonstrated the reverse pattern. Verbal and nonverbal IQ interacted to predict reading and math performance. Conclusions Lower SES is associated with lower verbal IQ in economically disadvantaged Hispanic children with SBM. Academic achievement is largely correlated with verbal IQ, but children with lower verbal IQ may partially compensate with higher nonverbal ability. PMID:20150339

  19. Parental sex effect in spina bifida: a role for genomic imprinting?

    PubMed

    Chatkupt, S; Lucek, P R; Koenigsberger, M R; Johnson, W G

    1992-11-01

    Fifty families (491 individuals in 137 sibships) with more than one living case of isolated, nonsyndromic spina bifida (SB) were analyzed genetically. There were twice as many gene-carrier females (56) as gene-carrier males (28) (P < 0.005). This was not an artifact of ascertainment bias because the sex ratio of gene-carriers was the same whether the pedigree was obtained through the proband's father or mother. Also, this effect was not observed in other disorders analyzed by the same method. Neither was the effect due to differential fertility because the number and sex of affected and unaffected children per gene-carrier parent were not different for male or female gene-carrier parents. There was no evidence that the missing male gene-carriers were lost by selective spontaneous abortion. There was no deficit of male-to-male or male-to-female transmission, excluding simple X-linked or simple mitochondrial inheritance. If genomic imprinting plays a role in the unequal female and male carrier frequencies in SB, penetrance should differ with parental sex. Penetrance was higher for offspring of female parents than of male parents, but the difference was not statistically significant. In addition, both male and female gene-carriers were frequently found in the same pedigree. Thus, the present data suggest a possible role for imprinting in SB.

  20. 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.

  1. 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

  2. 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

  3. Application potential of bone marrow mesenchymal stem cell (BMSCs) based tissue-engineering for spinal cord defect repair in rat fetuses with spina bifida aperta.

    PubMed

    Li, Xiaoshuai; Yuan, Zhengwei; Wei, Xiaowei; Li, Hui; Zhao, Guifeng; Miao, Jiaoning; Wu, Di; Liu, Bo; Cao, Songying; An, Dong; Ma, Wei; Zhang, Henan; Wang, Weilin; Wang, Qiushi; Gu, Hui

    2016-04-01

    Spina bifida aperta are complex congenital malformations resulting from failure of fusion in the spinal neural tube during embryogenesis. Despite surgical repair of the defect, most patients who survive with spina bifida aperta have a multiple system handicap due to neuron deficiency of the defective spinal cord. Tissue engineering has emerged as a novel treatment for replacement of lost tissue. This study evaluated the prenatal surgical approach of transplanting a chitosan-gelatin scaffold seeded with bone marrow mesenchymal stem cells (BMSCs) in the healing the defective spinal cord of rat fetuses with retinoic acid induced spina bifida aperta. Scaffold characterisation revealed the porous structure, organic and amorphous content. This biomaterial promoted the adhesion, spreading and in vitro viability of the BMSCs. After transplantation of the scaffold combined with BMSCs, the defective region of spinal cord in rat fetuses with spina bifida aperta at E20 decreased obviously under stereomicroscopy, and the skin defect almost closed in many fetuses. The transplanted BMSCs in chitosan-gelatin scaffold survived, grew and expressed markers of neural stem cells and neurons in the defective spinal cord. In addition, the biomaterial presented high biocompatibility and slow biodegradation in vivo. In conclusion, prenatal transplantation of the scaffold combined with BMSCs could treat spinal cord defect in fetuses with spina bifida aperta by the regeneration of neurons and repairmen of defective region.

  4. Monte Carlo fluorescence microtomography

    NASA Astrophysics Data System (ADS)

    Cong, Alexander X.; Hofmann, Matthias C.; Cong, Wenxiang; Xu, Yong; Wang, Ge

    2011-07-01

    Fluorescence microscopy allows real-time monitoring of optical molecular probes for disease characterization, drug development, and tissue regeneration. However, when a biological sample is thicker than 1 mm, intense scattering of light would significantly degrade the spatial resolution of fluorescence microscopy. In this paper, we develop a fluorescence microtomography technique that utilizes the Monte Carlo method to image fluorescence reporters in thick biological samples. This approach is based on an l0-regularized tomography model and provides an excellent solution. Our studies on biomimetic tissue scaffolds have demonstrated that the proposed approach is capable of localizing and quantifying the distribution of optical molecular probe accurately and reliably.

  5. The C677T mutation of the 5,10-methylenetetrahydrofolate reductase gene is a moderate risk factor for spina bifida in Italy.

    PubMed Central

    de Franchis, R; Buoninconti, A; Mandato, C; Pepe, A; Sperandeo, M P; Del Gado, R; Capra, V; Salvaggio, E; Andria, G; Mastroiacovo, P

    1998-01-01

    OBJECTIVE: To estimate the risk for spina bifida associated with the common mutation C677T of the MTHFR gene in a country with a relatively low prevalence of NTDs. DESIGN: Case-control study. SUBJECTS: Cases: 203 living patients affected with spina bifida (173 myelomeningocele and 30 lipomeningocele); controls: 583 subjects (306 young adults and 277 unselected newborns) from northern and central-southern Italy. SETTING: Cases: three spina bifida centres; young adult controls: DNA banks; newborn controls: regional neonatal screening centres. MAIN OUTCOME MEASURES: Prevalence of the C677T genotypes in cases and controls by place of birth; odds ratios for spina bifida and estimated attributable fraction. RESULTS: The prevalence of T/T, T/C, and C/C genotype was 16.6%, 53.7%, and 29.7% in controls and 25.6%, 43.8%, and 30.6% in cases, respectively. We found no differences between type of defect or place of birth. The odds ratio for spina bifida associated with the T/T genotype v C/C plus T/C was 1.73 (95% CI 1.15, 2.59) and the corresponding attributable fraction was 10.8%. No increased risk was found for heterozygous patients (OR=0.79, 95% CI 0.53-1.18). CONCLUSION: This study, as well as the meta-analysis we updated, shows that homozygosity for the MTHFR C677T mutation is a moderate risk factor in Europe, and even in Italy where there is a relatively low prevalence of spina bifida. The estimated attributable fraction associated with this risk factor explains only a small proportion of cases preventable by periconceptional folic acid supplementation. Thus, other genes involved in folate-homocysteine metabolism, their interaction, and the interaction between genetic and environmental factors should be investigated further. PMID:9863598

  6. 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

  7. Prevalence and time trends of spina bifida in fourteen cities located in the Liaoning province of northeast China, 2006-2015.

    PubMed

    Ba, Gen; Wu, Qi-Jun; Chen, Yan-Ling; Huang, Yan-Hong; Gong, Ting-Ting

    2017-01-27

    The present study sought to assess the time trends of spina bifida on the basis of cases identified by the Liaoning Birth Defects Registry in 14 cities from 2006 to 2015. We calculated the prevalence of spina bifida, percent and average change of time trends, and contribution rates of each city. Poisson regression model was used to find the line of best fit for spina bifida prevalence by year, with year as a continuous independent variable. From 2006 to 2015, a total of 2,029 spina bifida cases were identified from 3,248,954 live births (6.25/10,000 live births). We observed statistically significant decreasing trend of overall time trend (11.57% each year). Chaoyang, Fuxin, and Huludao were the top three leading cities, with 14.30/10,000 live births, 9.70/10,000 live births, and 9.20/10,000 live births, respectively. Inversely, the bottom three cities with lowest prevalence were Anshan (2.64/10,000 live births), Dandong (3.43/10,000 live births), and Dalian (3.45/10,000 live births). Of note, we observed significant decreasing trends in over half of these cities (n = 8). In addition, the decreasing trend of overall time trend could be mainly attributed to cities of Shenyang, Fushun, and Jinzhou which accounted for nearly one third. In summary, our study suggested a decreasing time trend of spina bifida during the past decade in the Liaoning province. The findings of this study provide evidence that the nationwide folic acid supplement program has been an effective strategy to prevent spina bifida.

  8. Physical activity, exercise, and health-related measures of fitness in adults with spina bifida: a review of the literature.

    PubMed

    Crytzer, Theresa M; Dicianno, Brad E; Kapoor, Roohi

    2013-12-01

    Spina bifida (SB) is the most common birth defect in United States that results in permanent lifelong disability according to the Spina Bifida Association. Advancements in medical care have led to a longer life span and an increase in the risk of secondary conditions, for example, obesity, with age. The need to maintain a healthy and active lifestyle is even stronger in adults with SB than the general population. Our objective was to fill a gap in the literature by highlighting the current state of the literature on health-related measures of fitness, exercise, and physical activity (PA) in adults with SB. PubMed and Ovid were searched for articles by using the terms "spina bifida or myelomeningocele and exercise," published between January 1, 1988 and May 10, 2012. Results of studies showed that adults with SB had an inactive lifestyle, lower aerobic capacity, decreased level of daily PA, higher prevalence of obesity, and lower health-related quality of life compared with reference groups. Therapeutic interventions reduced pain, increased biomechanical efficiency during wheelchair propulsion, and improved PA and balance. Overall, the quality of the evidence on PA, exercise, and health-related measures of fitness is low in SB. Given misdistribution of adipose tissue, short stature, scoliosis, and joint contractures, future research should be conducted to determine the most reliable and low-cost methods of measuring body composition and to establish norms. Other reference standards, for example, aerobic capacity, require further development. Studies are needed to investigate lifestyle interventions that facilitate PA and exercise, and to determine the amount of exercise required to reduce secondary conditions as people with SB age.

  9. Spina bifida and anencephaly before and after folic acid mandate--United States, 1995-1996 and 1999-2000.

    PubMed

    2004-05-07

    Neural tube defects (NTDs) are serious birth defects of the spine (e.g., spina bifida) and the brain (e.g., anencephaly) that occur during early pregnancy, often before a woman knows she is pregnant; 50%-70% of these defects can be prevented if a woman consumes sufficient folic acid daily before conception and throughout the first trimester of her pregnancy. In 1992, to reduce the number of cases of spina bifida and other NTDs, the U.S. Public Health Service (USPHS) recommended that all women capable of becoming pregnant consume 400 microg of folic acid daily. Three approaches to increase folic acid consumption were cited: 1) improve dietary habits, 2) fortify foods with folic acid, and 3) use dietary supplements containing folic acid. Mandatory fortification of cereal grain products went into effect in January 1998; during October 1998-December 1999, the reported prevalence of spina bifida declined 31%, and the prevalence of anencephaly declined 16%. Other studies have indicated similar trends. To update the estimated numbers of NTD-affected pregnancies and births, CDC recently analyzed data from 23 population-based surveillance systems that include prenatal ascertainment of these birth defects. This report summarizes the results of that analysis, which indicate that the estimated number of NTD-affected pregnancies in the United States declined from 4,000 in 1995-1996 to 3,000 in 1999-2000. This decline in NTD-affected pregnancies highlights the partial success of the U.S. folic acid fortification program as a public health strategy. To reduce further the number of NTD-affected pregnancies, all women capable of becoming pregnant should follow the USPHS recommendation and consume 400 microg of folic acid every day.

  10. MCMini: Monte Carlo on GPGPU

    SciTech Connect

    Marcus, Ryan C.

    2012-07-25

    MCMini is a proof of concept that demonstrates the possibility for Monte Carlo neutron transport using OpenCL with a focus on performance. This implementation, written in C, shows that tracing particles and calculating reactions on a 3D mesh can be done in a highly scalable fashion. These results demonstrate a potential path forward for MCNP or other Monte Carlo codes.

  11. 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.

  12. Factors associated with the timeliness of postnatal surgical repair of spina bifida

    PubMed Central

    Cassell, Cynthia H.; Laditka, Sarah B.; Thibadeau, Judy K.; Correia, Jane; Grosse, Scott D.; Kirby, Russell S.

    2016-01-01

    Purpose Clinical guidelines recommend repair of open spina bifida (SB) prenatally or within the first days of an infant’s life. We examined maternal, infant, and health care system factors associated with time-to-repair among infants with postnatal repair. Methods This retrospective, statewide, population-based study examined infants with SB born in Florida 1998–2007, ascertained by the Florida Birth Defects Registry. We used procedure codes from hospital discharge records to identify the first recorded myelomeningocele repair (ICD-9 CM procedure code 03.52) among infants with birth hospitalizations. Using Poisson multivariable regression, we examined time-to-repair by hydrocephalus, SB type (isolated [no other coded major birth defect] versus non-isolated), and other selected factors. Results Of 199 infants with a recorded birth hospitalization and coded myelomeningocele repair, 87.9 % had hydrocephalus and 19.6 % had non-isolated SB. About 76.4 % of infants had repair by day 2 of life. In adjusted analyses, infants with hydrocephalus were more likely to have timely repair (adjusted prevalence ratio (aPR) = 1.48, 95 % confidence interval (CI) 1.02–2.14) than infants without hydrocephalus. SB type was not associated with repair timing. Infants born in lower level nursery care hospitals with were less likely to have timely repairs (aPR = 0.71, 95 % CI 0.52–0.98) than those born in higher level nursery care hospitals. Conclusions Most infants with SB had surgical repair in the first 2 days of life. Lower level birth hospital nursery care was associated with later repairs. Prenatal diagnosis can facilitate planning for a birth hospital with higher level of nursery care, thus improving opportunities for timely repair. PMID:27179533

  13. 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).

  14. A Description of Spina Bifida Cases and Co-Occurring Malformations, 1976–2011

    PubMed Central

    Parker, Samantha E.; Yazdy, Mahsa M.; Mitchell, Allen A.; Demmer, Laurie A.; Werler, Martha M.

    2015-01-01

    Mandatory folic acid fortification in the United States corresponded with a decline in the prevalence of spina bifida (SB). The aim of this study was to describe the epidemiologic characteristics of isolated versus non-isolated SB cases in both pre- and post-fortification periods. SB cases in the Slone Epidemiology Center Birth Defects Study from 1976 to 2011 without chromosomal anomalies and syndromes were included. A maternal interview, conducted within 6 months of delivery, collected information on demographics, reproductive history, diet, and supplement use. Daily folic acid intake in the periconceptional period was calculated using both dietary and supplement information and categorized as low intake (<400 μg/day) or high intake (≥400 μg/day). SB cases (n=1170) were classified as isolated (80.4%) or non-isolated (19.1%). Non-isolated cases were further divided into subgroups based on accompanying major malformations (midline, renal, genital, heart, laterality). Compared to non-isolated cases, isolated cases were more likely to be white, non-Hispanic and have more than 12 years of education. Cases in the renal, genital, and heart subgroups had the lowest proportions of mothers with a high folic acid intake. The change from pre- to post-fortification was associated with a decrease in the proportion of isolated cases from 83% to 72%, though in both periods isolated cases were more likely to be female and their mothers were more likely to have high folic acid intake. These findings highlight the importance of separating isolated and non-isolated cases in etiologic research of SB. PMID:24357196

  15. 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

  16. Epidemiologic and genetic aspects of spina bifida and other neural tube defects

    PubMed Central

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

    2011-01-01

    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 health officials to design and implement policies to prevent NTD pregnancies, and (c) individuals to take precautions to reduce the chance of having an NTD-affected pregnancy. Despite extensive research, our knowledge of the genetic etiology of human NTDs is limited. Although more than 200 small animal models with NTDs exist, most of these models do not replicate the human disease phenotype. Over a hundred candidate genes have been examined for risk association to human SB. The candidate genes studied include those important in folic acid metabolism, glucose metabolism, retinoid metabolism, and apoptosis. Many genes that regulate transcription in early embryogenesis and maintain planar cell polarity have also been tested as candidates. Additionally, genes identified through mouse models of NTDs have been explored as candidates. We do not know how many genes in the human genome may confer risk for NTDs in human. Less than 20% of the studied candidate genes have been determined to confer even a minor effect on risk association. Many studies have provided conflicting conclusions due to limitations in study design that potentially affect the power of statistical analysis. Future directions such as genomewide association studies (GWAS) and whole exome or even whole genome sequencing are discussed as possible avenues to identify genes that affect risk for human NTDs. PMID:20419766

  17. GDNF plasma levels in spina bifida: correlation with severity of spinal damage and motor function.

    PubMed

    Chiaretti, Antonio; Rendeli, Claudia; Antonelli, Alessia; Barone, Giuseppe; Focarelli, Benedetta; Tabacco, Fabrizia; Massimi, Luca; Ausili, Emanuele

    2008-12-01

    Glial-derived neurotrophic factor (GDNF) is one of several powerful survival factors for spinal motoneurons that play a key role in sprouting, synaptic plasticity, and reorganization after spinal cord damage. The aim of this study was to investigate the expression of GDNF in plasma of children with spina bifida (SB) and to determine its correlation with both the severity of spinal cord damage and the motor function of these patients. To measure the GDNF expression, we collected plasma samples from 152 children with SB and in 149 matched controls. Endogenous GDNF levels were quantified using a two-site immuno-enzymatic assay. The statistical analysis was performed using the Mann-Whitney two-tailed two-sample test. In children with SB the mean levels of GDNF (131.2 +/- 69.6 pg/mL) were significantly higher (p < 0.001) with respect to the mean levels of the control group (102.7 +/- 6.8 pg/mL). Moreover, in open SB, the GDNF levels (139.2 +/- 81.1 pg/mL) were significantly higher (p < 0.05) with respect to closed SB (117.2 +/- 41.3 pg/mL). In terms of the motor function of patients, we found that in children with poorer motor function, the GDNF levels (134.5 +/- 67.4 pg/mL) were higher, but not statistically significant (p < 0.1), than in patients with better motor outcome (122.3 +/- 72.2 pg/mL). Our study demonstrates GDNF over-expression in children with SB. This upregulation is significantly associated with the severity of spinal cord damage in SB patients and appears to correlate with poor motor function of children, representing an important biochemical marker of the severity of spine injury.

  18. Quality of life related to urinary continence in adult spina bifida patients

    PubMed Central

    Dong, Caroline; Casey, Jessica T.; Greiman, Alyssa; Mukherjee, Shubhra; Kielb, Stephanie J.

    2015-01-01

    Introduction To analyze the correlations of bladder management technique, ambulatory status and urologic reconstruction on quality of life (QOL) as affected by urinary symptoms in adult spina bifida (SB) patients. Material and methods Sixty–six adult SB patients completed the RAND 36–Item Health Survey (mSF–36) and Incontinence Quality of Life (I–QOL). Demographic information, history of urinary reconstruction, and bladder management techniques were reviewed and analyzed with respect to survey scores. Results Mean age of patients was 32.3 (SD ±7.2) years and 44 patients (66.7%) were female. Forty–five patients (68.2%) were mainly ambulatory, 21 (31.8%) use a wheelchair and 10 (15.2%) had urologic reconstruction, while 56 (83.3%) did not. Twelve patients (18.2%) void, 42 (63.6%) perform clean intermittent catheterization (CIC), 4 (6.1%) use an indwelling catheter, 3 (4.5%) have an ileal conduit (IC) and 5 (7.6%) mainly use diapers. Mean mSF–36 General Health score was 56.5 (SD ±22.9) and mean I–QOL Sum score was 50.9 (SD ±21.7), where lower scores reflect lower QOL. mSF–36 and I–QOL scores did not significantly correlate with bladder management technique, ambulatory status or urologic reconstruction. A correlation was noted between I–QOL scales and most mSF–36 scales (all p <0.02). Conclusions In our cohort study of adult SB patients, bladder management technique and urologic reconstruction did not correlate with urinary (I–QOL) or general health (mSF–36) domains, although I–QOL and mSF–36 scores correlated closely, suggesting urinary continence is significantly related to general QOL. However, we are unable to identify a single factor that improves either urinary or general QOL. PMID:25914840

  19. Effects of low-frequency electrical stimulation on cumulative fatigue and muscle tone of the erector spinae

    PubMed Central

    Kang, Da-Haeng; Jeon, Jae-Keun; Lee, Joon-Hee

    2015-01-01

    [Purpose] The aim of this study was to determine the effect of low-frequency electrical stimulation on fatigue recovery of the erector spinae with cumulative fatigue induced by repeated lifting and lowering work. [Subjects] Thirty-two healthy men volunteered to participate in this study and they were randomly divided into three groups: a MC group of 12 persons who underwent microcurrent, a TENS group of 10 persons who underwent Transcutaneous electrical nerve stimulation, and a control group of 10 persons who only rested. [Methods] Cumulative fatigue was induced and then, EMG, muscle tone, CK and LDH serum levels of the erector spinae were measured. Each group then underwent the assigned intervention and was re-measured. To analyze the differences in fatigue between before and after the intervention, the paired t-test was conducted, while groups were compared using analysis of covariance with a control group. [Results] The MC groups showed a significant reduction in muscle fatigue and decreased muscle tone when compared to the control group. However, no significant differences were found between the TENS and control groups. [Conclusion] These results suggest that microcurrent stimulation was effective for recovery from cumulative muscle fatigue while TENS had no effect. PMID:25642049

  20. Effects of low-frequency electrical stimulation on cumulative fatigue and muscle tone of the erector spinae.

    PubMed

    Kang, Da-Haeng; Jeon, Jae-Keun; Lee, Joon-Hee

    2015-01-01

    [Purpose] The aim of this study was to determine the effect of low-frequency electrical stimulation on fatigue recovery of the erector spinae with cumulative fatigue induced by repeated lifting and lowering work. [Subjects] Thirty-two healthy men volunteered to participate in this study and they were randomly divided into three groups: a MC group of 12 persons who underwent microcurrent, a TENS group of 10 persons who underwent Transcutaneous electrical nerve stimulation, and a control group of 10 persons who only rested. [Methods] Cumulative fatigue was induced and then, EMG, muscle tone, CK and LDH serum levels of the erector spinae were measured. Each group then underwent the assigned intervention and was re-measured. To analyze the differences in fatigue between before and after the intervention, the paired t-test was conducted, while groups were compared using analysis of covariance with a control group. [Results] The MC groups showed a significant reduction in muscle fatigue and decreased muscle tone when compared to the control group. However, no significant differences were found between the TENS and control groups. [Conclusion] These results suggest that microcurrent stimulation was effective for recovery from cumulative muscle fatigue while TENS had no effect.

  1. 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.

  2. Changing the stability conditions in a back squat: the effect on maximum load lifted and erector spinae muscle activity.

    PubMed

    Fletcher, Iain M; Bagley, Ashley

    2014-11-01

    The aim of this study was to identify how changes in the stability conditions of a back squat affect maximal loads lifted and erector spinae muscle activity. Fourteen male participants performed a Smith Machine (SM) squat, the most stable condition, a barbell back (BB) squat, and Tendo-destabilizing bar (TBB) squat, the least stable condition. A one repetition max (1-RM) was established in each squat condition, before electromyography (EMG) activity of the erector spinae was measured at 85% of 1-RM. Results indicated that the SM squat 1-RM load was significantly (p = 0.006) greater (10.9%) than the BB squat, but not greater than the TBB squat. EMG results indicated significantly greater (p < 0.05) muscle activation in the TBB condition compared to other conditions. The BB squat produced significantly greater (p = 0.036) EMG activity compared to the SM squat. A greater stability challenge applied to the torso seems to increase muscle activation. The maximum loads lifted in the most stable and unstable squats were similar. However, the lift with greater stability challenge required greatest muscle activation. The implications of this study may be important for training programmes; if coaches wish to challenge trunk stability, while their athletes lift maximal loads designed to increase strength.

  3. Quantum Gibbs ensemble Monte Carlo

    SciTech Connect

    Fantoni, Riccardo; Moroni, Saverio

    2014-09-21

    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.

  4. Wormhole Hamiltonian Monte Carlo

    PubMed Central

    Lan, Shiwei; Streets, Jeffrey; Shahbaba, Babak

    2015-01-01

    In machine learning and statistics, probabilistic inference involving multimodal distributions is quite difficult. This is especially true in high dimensional problems, where most existing algorithms cannot easily move from one mode to another. To address this issue, we propose a novel Bayesian inference approach based on Markov Chain Monte Carlo. Our method can effectively sample from multimodal distributions, especially when the dimension is high and the modes are isolated. To this end, it exploits and modifies the Riemannian geometric properties of the target distribution to create wormholes connecting modes in order to facilitate moving between them. Further, our proposed method uses the regeneration technique in order to adapt the algorithm by identifying new modes and updating the network of wormholes without affecting the stationary distribution. To find new modes, as opposed to redis-covering those previously identified, we employ a novel mode searching algorithm that explores a residual energy function obtained by subtracting an approximate Gaussian mixture density (based on previously discovered modes) from the target density function. PMID:25861551

  5. Wormhole Hamiltonian Monte Carlo.

    PubMed

    Lan, Shiwei; Streets, Jeffrey; Shahbaba, Babak

    2014-07-31

    In machine learning and statistics, probabilistic inference involving multimodal distributions is quite difficult. This is especially true in high dimensional problems, where most existing algorithms cannot easily move from one mode to another. To address this issue, we propose a novel Bayesian inference approach based on Markov Chain Monte Carlo. Our method can effectively sample from multimodal distributions, especially when the dimension is high and the modes are isolated. To this end, it exploits and modifies the Riemannian geometric properties of the target distribution to create wormholes connecting modes in order to facilitate moving between them. Further, our proposed method uses the regeneration technique in order to adapt the algorithm by identifying new modes and updating the network of wormholes without affecting the stationary distribution. To find new modes, as opposed to redis-covering those previously identified, we employ a novel mode searching algorithm that explores a residual energy function obtained by subtracting an approximate Gaussian mixture density (based on previously discovered modes) from the target density function.

  6. 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.

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

    PubMed Central

    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. PMID:27065555

  8. 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…

  9. Isotropic Monte Carlo Grain Growth

    SciTech Connect

    Mason, J.

    2013-04-25

    IMCGG performs Monte Carlo simulations of normal grain growth in metals on a hexagonal grid in two dimensions with periodic boundary conditions. This may be performed with either an isotropic or a misorientation - and incliantion-dependent grain boundary energy.

  10. A patient with DiGeorge syndrome with spina bifida and sacral myelomeningocele, who developed both hypocalcemia-induced seizure and epilepsy.

    PubMed

    Kinoshita, Hiroyuki; Kokudo, Takashi; Ide, Takafumi; Kondo, Yasushi; Mori, Tokuo; Homma, Yasunobu; Yasuda, Mutsuko; Tomiyama, Junji; Yakushiji, Fumiatsu

    2010-06-01

    DiGeorge syndrome - a component of the 22q11 deletion syndrome - causes a disturbance in cervical neural crest migration that results in parathyroid hypoplasia. Patients can develop hypocalcemia-induced seizures. Spina bifida is caused by failure of neurulation, including a disturbance in the adhesion processes at the neurula stage. Spina bifida has been reported as a risk factor for epilepsy. We report, for the first time, the case of a patient with DiGeorge syndrome with spina bifida and sacral myelomeningocele, who developed both hypocalcemia-induced seizures and epilepsy. The patient had spina bifida and sacral myelomeningocele at birth. At the age of 13 years, he experienced a seizure for the first time. At this time, the calcium concentration was normal. An electroencephalogram (EEG) proved that the seizure was due to epilepsy. Antiepileptic medications controlled the seizure. At the age of 29, the patient's calcium concentration began to reduce. At the age of 40, hypocalcemia-induced seizure occurred. At this time, the calcium concentration was 5.5mg/dL (reference range, 8.7-10.1mg/dL). The level of intact parathyroid hormone (PTH) was 6 pg/mL (reference range, 10-65 pg/mL). Chromosomal and genetic examinations revealed a deletion of TUP-like enhancer of split gene 1 (tuple1)-the diagnostic marker of DiGeorge syndrome. Many patients with DiGeorge syndrome have cardiac anomalies; however, our patient had none. We propose that the association among DiGeorge syndrome, spina bifida, epilepsy, cardiac anomaly, 22q11, tuple1, and microdeletion inheritance should be clarified for appropriate diagnosis and treatment.

  11. Reverse Thermal Gel for In Utero Coverage of Spina Bifida Defects: An Innovative Bioengineering Alternative to Open Fetal Repair.

    PubMed

    Marwan, Ahmed I; Williams, Sarah M; Bardill, James R; Gralla, Jane; Abdul-Aziz, Noraishah M; Park, Daewon

    2017-01-30

    Current state-of-the-art management of open spina bifida defects entails an open fetal surgery approach associated with significant morbidities. In an attempt to reduce these risks and provide for an earlier minimally invasive repair, it is aimed to develop and characterize an innovative alternative using a unique reverse thermal gel. This study focuses on characterization of the physical and biological properties of the polymer and its in vivo applicability. Based on the knowledge and benchmarking, the "ideal" biomaterial should have the following characteristics: stability in amniotic fluid, limited permeability, biocompatibility, biologically functional, nontoxic, ability to support cellular functions, and in vivo applicability. The results demonstrate that the polymer possesses a unique ultrastructure, is stable in amniotic fluid, possesses limited yet predictable permeability, biocompatible with cells exposed in neural tube defects, is nontoxic, and can support cellular migration. These characteristics make it a potential novel alternative to open fetal repairs.

  12. Observed Differences in Social Behaviors Exhibited in Peer Interactions Between Youth With Spina Bifida and Their Peers: Neuropsychological Correlates

    PubMed Central

    Lennon, Jaclyn M.; Kolbuck, Victoria D.; Zebracki, Kathy; Roache, Caitlin R.; Holmbeck, Grayson N.

    2015-01-01

    Objective To identify differences in social behaviors in observed peer interactions between children with spina bifida (SB) and peers, and to examine neuropsychological correlates of these differences. Method A total of 100 youth (aged 8–15 years) with SB and peers participated in video-recorded interaction tasks, which were coded for interaction style, affect, and collaboration. Children with SB also completed a neuropsychological test battery. Results Children with SB demonstrated less adaptive social behaviors in peer interactions, particularly within the interaction style domain. Observational items found to be different between children with SB and their peers were best predicted by social language and attention abilities. Conclusions Children with SB exhibit a less adaptive interaction style and lower levels of social dominance but are comparable with typically developing peers on other social behaviors. The observed group differences may have a neuropsychological basis. PMID:25427551

  13. Spina cortica and Tapetum spinosus, two new microstructures of flight feathers: description, function and distribution in modern birds.

    PubMed

    Straker, L C; Raposo, M A; Attias, Márcia

    2008-05-01

    The importance of feathers for the avian group has made them one of the most studied epidermal structures both from the morphological and evolutionary point of view. Surprisingly, our observations by Scanning Electron Microscopy detected the presence of two structures widely distributed within different avian groups and not yet described. In this paper we describe these two new structures (Spina cortica and Tapetum spinosus) and map their distribution within modern birds. The S. cortica is a thorn-like microstructure that grows on the barb cortex and the T. spinosus is the assemblage of these thorns. The distribution of these new structures among birds and their morphological diversity could be of great interest to taxonomists and evolutionary biologists interested in the origin of bird flight.

  14. Left-sided Poland's syndrome in a girl with rare associations like spina bifida and diaphragmatic hernia

    PubMed Central

    C, Sunitha V; Narayanan, Sathya; Nair, Pradeep Pankajakshan; Prakash, Manikka Lakshmanan

    2013-01-01

    Poland's syndrome is a rare congenital anomaly characterised by partial or complete absence of sternocostal head of pectoralis major muscle and anomalies of ipsilateral hand and digits. Other associated anomalies involving anterior thoracic wall, breast, diaphragm and vertebrae have also been reported in various cases. We report a case of a 10-year-old girl, with features of left-sided Poland's syndrome associated with spina bifida, dextroposition of the heart and left-sided diaphragmatic hernia. These are rare associations of Poland's syndrome. She was investigated with chest X-ray, contrast-enhanced CT of the thorax, ultrasonography of abdomen and echocardiography which helped in arriving at an accurate diagnosis and assessing all the associated abnormalities. PMID:24057335

  15. 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

  16. [A case of conus medullaris infarction expanding to the vertebral bodies, major psoas and erector spinae muscles].

    PubMed

    Konno, Takuya; Suwabe, Tatsuya; Kasahara, Sou; Umeda, Yoshitaka; Oyake, Mutsuo; Fujita, Nobuya

    2015-01-01

    A 77-year-old woman presented with conus medullaris and cauda equina syndrome following a sudden pain in the bilateral lower abdomen and right buttock. Lumbar magnetic resonance imaging (MRI) showed not only a conus medullaris lesion, but also several lesions in the vertebral bodies (L1, L2), right major psoas muscle, right multifidus muscle and bilateral erector spinae muscles. As these areas receive blood supply from each branch of the same segmental artery, we considered all of the lesions as infarctions that were a result of a single parent vessel occlusion. It is known that a vertebral body lesion can be accompanied by a spinal cord infarction, but in combination with infarction of a muscle has not been reported. This is the first report of a concomitant spinal cord and muscle infarction revealed by MRI. It is noteworthy that a spinal cord infarction could expand not only to neighboring vertebral bodies, but also to muscles.

  17. The National Spina Bifida Patient Registry: Profile of a Large Cohort of Participants from the First 10 Clinics

    PubMed Central

    Sawin, Kathleen J.; Liu, Tiebin; Ward, Elisabeth; Thibadeau, Judy; Schechter, Michael S.; Soe, Minn M.; Walker, William

    2015-01-01

    Objective To use data from the US National Spina Bifida Patient Registry (NSBPR) to describe variations in Contexts of Care, Processes of Care, and Health Outcomes among individuals with spina bifida (SB) receiving care in 10 clinics. Study design Reported here are baseline cross-sectional data representing the first visit of 2172 participants from 10 specialized, multidisciplinary SB clinics participating in the NSBPR. We used descriptive statistics, the Fisher exact test, χ2 test, and Wilcoxon rank-sum test to examine the data. Results The mean age was 10.1 (SD 8.1) years with slightly more female subjects (52.5%). The majority was white (63.4%) and relied upon public insurance (53.5%). One-third had sacral lesions, 44.8% had mid-low lumbar lesions, and 24.9% had high lumbar and thoracic lesions. The most common surgery was ventricular shunt placement (65.7%). The most common bladder-management technique among those with bladder impairment was intermittent catheterization (69.0%). Almost 14% experienced a pressure ulcer in the last year. Of those ages 5 years or older with bowel or bladder impairments, almost 30% were continent of stool; a similar percentage was continent of urine. Most variables were associated with type of SB diagnosis. Conclusion The NSBPR provides a cross section of a predominantly pediatric population of patients followed in specialized SB programs. There were wide variations in the variables studied and major differences in Context of Care, Processes of Care, and Health Outcomes by type of SB. Such wide variation and the differences by type of SB should be considered in future analyses of outcomes. PMID:25444012

  18. Young adults with spina bifida transitioned to a medical home: a survey of medical care in Jacksonville, Florida.

    PubMed

    Aguilera, Antonio M; Wood, David L; Keeley, Cortney; James, Hector E; Aldana, Philipp R

    2015-10-23

    OBJECT The transition of the young adult with spina bifida (YASB) from pediatric to adult health care is considered a priority by organized pediatrics. There is a paucity of transition programs and related studies. Jacksonville Health and Transition Services (JaxHATS) is one such transition program in Jacksonville, Florida. This study's purpose was to evaluate the health care access, utilization, and quality of life (QOL) of a group of YASBs who have transitioned from pediatric care. METHODS A survey tool addressing access to health care and quality of health and life was developed based on an established survey. Records of the Spinal Defects Clinic held at Wolfson Children's Hospital and JaxHATS Clinic were reviewed and YASBs (> 18 and < 30 years old) were identified. RESULTS Ten of the 12 invited YASBs in the Jacksonville area completed the surveys. The mean age of respondents was 25.1 years. All reported regular medical home visits, 8 with JaxHATS and 2 with other family care groups. All reported easy access to medical care and routine visits to spina bifida (SB) specialists; none reported difficulty or delays in obtaining health care. Only 2 patients required emergent care in the last year for an SB-related medical problem. Seven respondents reported very good to excellent QOL. Family, lifestyle, and environmental factors were also examined. CONCLUSIONS In this small group of YASBs with a medical home, easy access to care for medical conditions was the norm, with few individuals having recent emergency visits and almost all reporting at least a good overall QOL. Larger studies of YASBs are needed to evaluate the positive effects of medical homes on health and QOL in this population.

  19. 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.

  20. MontePython: Implementing Quantum Monte Carlo using Python

    NASA Astrophysics Data System (ADS)

    Nilsen, Jon Kristian

    2007-11-01

    We present a cross-language C++/Python program for simulations of quantum mechanical systems with the use of Quantum Monte Carlo (QMC) methods. We describe a system for which to apply QMC, the algorithms of variational Monte Carlo and diffusion Monte Carlo and we describe how to implement theses methods in pure C++ and C++/Python. Furthermore we check the efficiency of the implementations in serial and parallel cases to show that the overhead using Python can be negligible. Program summaryProgram title: MontePython Catalogue identifier: ADZP_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 49 519 No. of bytes in distributed program, including test data, etc.: 114 484 Distribution format: tar.gz Programming language: C++, Python Computer: PC, IBM RS6000/320, HP, ALPHA Operating system: LINUX Has the code been vectorised or parallelized?: Yes, parallelized with MPI Number of processors used: 1-96 RAM: Depends on physical system to be simulated Classification: 7.6; 16.1 Nature of problem: Investigating ab initio quantum mechanical systems, specifically Bose-Einstein condensation in dilute gases of 87Rb Solution method: Quantum Monte Carlo Running time: 225 min with 20 particles (with 4800 walkers moved in 1750 time steps) on 1 AMD Opteron TM Processor 2218 processor; Production run for, e.g., 200 particles takes around 24 hours on 32 such processors.

  1. Multilevel sequential Monte Carlo samplers

    SciTech Connect

    Beskos, Alexandros; Jasra, Ajay; Law, Kody; Tempone, Raul; Zhou, Yan

    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 hL. 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 levels ${\\infty}$ >h0>h1 ...>hL. 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.

  2. 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 hL. 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 » $${\\infty}$$ >h0>h1 ...>hL. 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

  3. 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

  4. Suitable Candidates for Monte Carlo Solutions.

    ERIC Educational Resources Information Center

    Lewis, Jerome L.

    1998-01-01

    Discusses Monte Carlo methods, powerful and useful techniques that rely on random numbers to solve deterministic problems whose solutions may be too difficult to obtain using conventional mathematics. Reviews two excellent candidates for the application of Monte Carlo methods. (ASK)

  5. A Classroom Note on Monte Carlo Integration.

    ERIC Educational Resources Information Center

    Kolpas, Sid

    1998-01-01

    The Monte Carlo method provides approximate solutions to a variety of mathematical problems by performing random sampling simulations with a computer. Presents a program written in Quick BASIC simulating the steps of the Monte Carlo method. (ASK)

  6. Applications of Monte Carlo Methods in Calculus.

    ERIC Educational Resources Information Center

    Gordon, Sheldon P.; Gordon, Florence S.

    1990-01-01

    Discusses the application of probabilistic ideas, especially Monte Carlo simulation, to calculus. Describes some applications using the Monte Carlo method: Riemann sums; maximizing and minimizing a function; mean value theorems; and testing conjectures. (YP)

  7. Strong-Meter and Weak-Meter Rhythm Identification in Spina Bifida Meningomyelocele and Volumetric Parcellation of Rhythm-Relevant Cerebellar Regions

    PubMed Central

    Dennis, Maureen; Hopyan, Talar; Juranek, Jenifer; Cirino, Paul T.; Hasan, Khader M.; Fletcher, Jack

    2011-01-01

    Children with spina bifida meningomyelocele (SBM) are impaired relative to controls in terms of discriminating strong-meter and weak-meter rhythms, so congenital cerebellar dysmorphologies that affect rhythmic movements also disrupt rhythm perception. Cerebellar parcellations in children with SBM showed an abnormal configuration of volume fractions in cerebellar regions important for rhythm function: a smaller inferior-posterior lobe, and larger anterior and superior-posterior lobes. PMID:19673758

  8. Effect of the cervical flexion angle during smart phone use on muscle fatigue of the cervical erector spinae and upper trapezius.

    PubMed

    Lee, Sangyong; Lee, Daehee; Park, Jungseo

    2015-06-01

    [Purpose] The purpose of this study was to examine the influence of the cervical flexion angle when using a smart phone on muscle fatigue of the cervical erector spinae (CES) and upper trapezius (UT). [Subjects] This study recruited 12 healthy adults. [Methods] Each subject sat on a chair, with his/her back against the wall and held a smart phone with both hands. Fatigue of the neck and shoulder muscles at different cervical flexion angles (0°, 30°, and 50°) was measured by electromyography. The following muscles were assessed: the right upper trapezius (RtUT), left upper trapezius (LtUT), right cervical erector spinae (RtCES), and left cervical erector spinae (LtCES). A cervical range of motion instrument was attached to the subjects' heads to measure the cervical angle during the experiment. [Results] The RtUT and LtUT showed the highest muscle fatigue at a cervical flexion angle of 50° and the lowest fatigue at an angle of 30°. There was no significant difference in the muscle fatigue of the RtCES and LtCES at any of the cervical flexion angles. [Conclusion] UT muscle fatigue depends on the cervical flexion angle when using a smart phone.

  9. 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.

  10. Monte Carlo Simulation of Plumes Spectral Emission

    DTIC Science & Technology

    2005-06-07

    Henyey − Greenstein scattering indicatrix SUBROUTINE Calculation of spectral (group) phase function of Monte - Carlo Simulation of Plumes...calculations; b) Computing code SRT-RTMC-NSM intended for narrow band Spectral Radiation Transfer Ray Tracing Simulation by the Monte - Carlo method with...project) Computing codes for random ( Monte - Carlo ) simulation of molecular lines with reference to a problem of radiation transfer

  11. 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…

  12. Muscle fibre size and type distribution in thoracic and lumbar regions of erector spinae in healthy subjects without low back pain: normal values and sex differences

    PubMed Central

    MANNION, A. F.; DUMAS, G. A.; COOPER, R. G.; ESPINOSA, F. J.; FARIS, M. W.; STEVENSON, J. M.

    1997-01-01

    This study sought to investigate the normal muscle fibre size and type distribution of the human erector spinae, both in thoracic and lumbar regions, in a group of 31 young healthy male (n=17) and female (n=14) volunteers. Two percutaneous muscle biopsy samples were obtained under local anaesthesia, from the belly of the left erector spinae, at the levels of the 10th thoracic and 3rd lumbar vertebrae. Samples were prepared for routine histochemistry for the identification of fibre types. Fibre size (cross-sectional area (CSA) and narrow diameter (ND)) was quantified using computerised image analysis. The mean CSA/ND for each fibre type was greater in the thoracic than the lumbar region, but there was no difference between the 2 regions either for percentage type I (i.e. percentage distribution by number), percentage type I area (i.e. relative area of the muscle occupied by type I fibres) or the ratio describing the size of the type I fibre relative to that of the type II. Men had larger fibres than women, for each fibre type and at both sampling sites. In the men, each fibre type was of a similar mean size, whereas in the women the type I fibres were considerably larger than both the type II A and type II B fibres, with no difference between the latter two. In both regions of the erector spinae there was no difference between men and women for the proportion (%) of a given fibre type, but the percentage type I fibre area was significantly higher in the women. The erector spinae display muscle fibre characteristics which are clearly very different from those of other skeletal muscles, and which, with their predominance of relatively large type I (slow twitch) fibres, befit their function as postural muscles. Differences between thoracic and lumbar fascicles of the muscle, and between the muscles of men and women, may reflect adaptive responses to differences in function. In assessing the degree of any pathological change in the muscle of patients with low back pain

  13. Monte Carlo methods in ICF

    SciTech Connect

    Zimmerman, G.B.

    1997-06-24

    Monte Carlo methods appropriate to simulate the transport of x-rays, neutrons, ion and electrons in Inertial Confinement Fusion targets are described and analyzed. The Implicit Monte Carlo method of x-ray transport handles symmetry within indirect drive ICF hohlraums well, but can be improved 50X in efficiency by angular biasing the x-rays towards the fuel capsule. Accurate simulation of thermonuclear burns nd burn diagnostics involves detailed particle source spectra, charged particle ranges, inflight reaction kinematics, corrections for bulk and thermal Doppler effects and variance reduction to obtain adequate statistics for rare events. It is found that the effects of angular Coulomb scattering must be included in models of charged particle transport through heterogeneous materials.

  14. The D0 Monte Carlo

    SciTech Connect

    Womersley, J. . Dept. of Physics)

    1992-10-01

    The D0 detector at the Fermilab Tevatron began its first data taking run in May 1992. For analysis of the expected 25 pb[sup [minus]1] data sample, roughly half a million simulated events will be needed. The GEANT-based Monte Carlo program used to generate these events is described, together with comparisons to test beam data. Some novel techniques used to speed up execution and simplify geometrical input are described.

  15. A Longitudinal Examination of Health-Related Quality of Life in Children and Adolescents With Spina Bifida

    PubMed Central

    Holmbeck, Grayson N.; Ros, Anna M.; Flores, Donna M.; Mir, Sophie A.; Varni, James W.

    2015-01-01

    Objective The current study examined (1) spina bifida (SB) youths’ health-related quality of life (HRQOL) compared with nonclinical and chronic health condition (CHC) samples, (2) parent–child agreement regarding HRQOL, and (3) prospective changes in HRQOL. Methods Child and parent-proxy reports of Pediatric Quality of Life were collected at two time waves (Time 1: N = 134, ages 8–15 years; Time 2: N = 109, ages 10–17 years) as part of a larger longitudinal study. Results SB youth had statistically and clinically reduced physical HRQOL compared with the nonclinical and CHC samples at both time points. There were significant discrepancies between youth and parent-proxy reports of HRQOL; youth reported higher levels of physical and social HRQOL than parents. The majority of parent- and child-reported HRQOL domains remained stable, yet youth-reported social HRQOL increased over time. Conclusions Youth with SB are at risk for poor HRQOL. Examining modifiable condition and social–environmental predictors of youth HRQOL will be important in informing future interventions. PMID:25434043

  16. Electromyographic responses of erector spinae and lower limb's muscles to dynamic postural perturbations in patients with adolescent idiopathic scoliosis.

    PubMed

    Farahpour, Nader; Ghasemi, Safoura; Allard, Paul; Saba, Mohammad Sadegh

    2014-10-01

    The aim of this study was to evaluate electromyographic (EMG) responses of erector spinae (ES) and lower limbs' muscles to dynamic forward postural perturbation (FPP) and backward postural perturbation (BPP) in patients with adolescent idiopathic scoliosis (AIS) and in a healthy control group. Ten right thoracic AIS patients (Cobb=21.6±4.4°) and 10 control adolescents were studied. Using bipolar surface electrodes, EMG activities of ES muscle at T10 (EST10) and L3 (ESL3) levels, biceps femoris (BF), gastrocnemius lateralis (G) and rectus femoris (RF) muscles in the right and the left sides during FPP and BPP were evaluated. Muscle responses were measured over a 1s time window after the onset of perturbation. In FPP test, the EMG responses of right EST10, ESL3 and BF muscles in the scoliosis group were respectively about 1.40 (p=0.035), 1.43 (p=0.07) and 1.45 (p=0.01) times greater than those in control group. Also, in BPP test, at right ESL3 muscle of the scoliosis group the EMG activity was 1.64 times higher than that in the control group (p=0.01). The scoliosis group during FPP displayed asymmetrical muscle responses in EST10 and BF muscles. This asymmetrical muscle activity in response to FPP is hypothesized to be a possible compensatory strategy rather than an inherent characteristic of scoliosis.

  17. 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

  18. Learner drivers with spina bifida and hydrocephalus: the relationship between perceptual-cognitive deficit and driving performance.

    PubMed

    Simms, B

    1986-12-01

    This study investigated the relationship between perceptual-cognitive skills and driving performance in a group of eleven learner drivers disabled by spina bifida and hydrocephalus. Perceptual-cognitive skills assessed include figure-ground discrimination, visual scanning/tracking, spatial orientation, language, reasoning and memory ability. Following ten hours driving tuition in suitably adapted cars, driving performance in off-road manoeuvres and in-traffic situations was measured. Results showed that the perceptual-cognitive skills of this group were in the low average or below average range compared to a non-handicapped population. Spearman Rank Order Correlations between clinical tests and driving performance indicated that although certain tests correlated with off-road manoeuvres, no perceptual measures were reliable indicators of in-traffic driving. There were indications that practical measures of spatial orientation and reasoning ability may be more relevant to some aspects of driving than tested perceptual skills. Memory for road signs, landmarks and routes was also investigated. Accurate retention seemed more dependent on general reasoning ability than tested aspects of memory functioning. It is suggested that as clinically tested perceptual skills do not seem to be reliable indicators of driving performance, an individual's test results should not be used to deter him from learning to drive.

  19. Improved age modelling and high-precision age estimates of late Quaternary tephras, for accurate palaeoclimate reconstruction

    NASA Astrophysics Data System (ADS)

    Blockley, Simon P. E.; Bronk Ramsey, C.; Pyle, D. M.

    2008-10-01

    The role of tephrochronology, as a dating and stratigraphic tool, in precise palaeoclimate and environmental reconstruction, has expanded significantly in recent years. The power of tephrochronology rests on the fact that a tephra layer can stratigraphically link records at the resolution of as little as a few years, and that the most precise age for a particular tephra can be imported into any site where it is found. In order to maximise the potential of tephras for this purpose it is necessary to have the most precise and robustly tested age estimate possible available for key tephras. Given the varying number and quality of dates associated with different tephras it is important to be able to build age models to test competing tephra dates. Recent advances in Bayesian age modelling of dates in sequence have radically extended our ability to build such stratigraphic age models. As an example of the potential here we use Bayesian methods, now widely applied, to examine the dating of some key Late Quaternary tephras from Italy. These are: the Agnano Monte Spina Tephra (AMST), the Neapolitan Yellow Tuff (NYT) and the Agnano Pomici Principali (APP), and all of them have multiple estimates of their true age. Further, we use the Bayesian approaches to generate a revised mixed radiocarbon/varve chronology for the important Lateglacial section of the Lago Grande Monticchio record, as a further illustration of what can be achieved by a Bayesian approach. With all three tephras we were able to produce viable model ages for the tephra, validate the proposed 40Ar/ 39Ar age ranges for these tephras, and provide relatively high precision age models. The results of the Bayesian integration of dating and stratigraphic information, suggest that the current best 95% confidence calendar age estimates for the AMST are 4690-4300 cal BP, the NYT 14320-13900 cal BP, and the APP 12380-12140 cal BP.

  20. Semistochastic Projector Monte Carlo Method

    NASA Astrophysics Data System (ADS)

    Petruzielo, F. R.; Holmes, A. A.; Changlani, Hitesh J.; Nightingale, M. P.; Umrigar, C. J.

    2012-12-01

    We introduce a semistochastic implementation of the power method to compute, for very large matrices, the dominant eigenvalue and expectation values involving the corresponding eigenvector. The method is semistochastic in that the matrix multiplication is partially implemented numerically exactly and partially stochastically with respect to expectation values only. Compared to a fully stochastic method, the semistochastic approach significantly reduces the computational time required to obtain the eigenvalue to a specified statistical uncertainty. This is demonstrated by the application of the semistochastic quantum Monte Carlo method to systems with a sign problem: the fermion Hubbard model and the carbon dimer.

  1. Multidimensional stochastic approximation Monte Carlo

    NASA Astrophysics Data System (ADS)

    Zablotskiy, Sergey V.; Ivanov, Victor A.; Paul, Wolfgang

    2016-06-01

    Stochastic Approximation Monte Carlo (SAMC) has been established as a mathematically founded powerful flat-histogram Monte Carlo method, used to determine the density of states, g (E ) , of a model system. We show here how it can be generalized for the determination of multidimensional probability distributions (or equivalently densities of states) of macroscopic or mesoscopic variables defined on the space of microstates of a statistical mechanical system. This establishes this method as a systematic way for coarse graining a model system, or, in other words, for performing a renormalization group step on a model. We discuss the formulation of the Kadanoff block spin transformation and the coarse-graining procedure for polymer models in this language. We also apply it to a standard case in the literature of two-dimensional densities of states, where two competing energetic effects are present g (E1,E2) . We show when and why care has to be exercised when obtaining the microcanonical density of states g (E1+E2) from g (E1,E2) .

  2. Single scatter electron Monte Carlo

    SciTech Connect

    Svatos, M.M.

    1997-03-01

    A single scatter electron Monte Carlo code (SSMC), CREEP, has been written which bridges the gap between existing transport methods and modeling real physical processes. CREEP simulates ionization, elastic and bremsstrahlung events individually. Excitation events are treated with an excitation-only stopping power. The detailed nature of these simulations allows for calculation of backscatter and transmission coefficients, backscattered energy spectra, stopping powers, energy deposits, depth dose, and a variety of other associated quantities. Although computationally intense, the code relies on relatively few mathematical assumptions, unlike other charged particle Monte Carlo methods such as the commonly-used condensed history method. CREEP relies on sampling the Lawrence Livermore Evaluated Electron Data Library (EEDL) which has data for all elements with an atomic number between 1 and 100, over an energy range from approximately several eV (or the binding energy of the material) to 100 GeV. Compounds and mixtures may also be used by combining the appropriate element data via Bragg additivity.

  3. Timescales of magma processes occurred prior to recent Campi Flegrei caldera eruptions: first results from diffusion profiles on plagioclase phenocrysts

    NASA Astrophysics Data System (ADS)

    D'Antonio, Massimo; Arienzo, Ilenia; Fedele, Lorenzo; Iovine, Raffaella; Carmine Mazzeo, Fabio; Civetta, Lucia; Orsi, Giovanni; Wörner, Gerhard

    2015-04-01

    Knowledge of the timescales of magma rising and stagnation, as well as mingling/mixing processes occurring in the shallow plumbing system of an active volcano is crucial for volcanic hazard assessment and risk mitigation. Among few recently developed methodologies, high-precision, high spatial resolution analysis of major-, minor- and trace elements on zoned phenocrysts through electron microprobe techniques represents a powerful tool to provide good estimates of timescales of pre-eruptive magma rising, stagnation and/or mingling/mixing processes. To this purpose, volcanic rock samples of trachytic composition representative of the Agnano-Monte Spina eruption (4.7 ka CAL BP) occurred at the Campi Flegrei caldera (southern Italy) have been selected. The investigation has been carried out in the framework of Project V2 - Precursori di Eruzioni, funded by the Italian Dipartimento per la Protezione Civile - Istituto Nazionale di Geofisica e Vulcanologia. The investigated rock samples are pumice fragments from which double-polished, 100 µm thick thin sections have been prepared for analytical purposes. Back-scattered electrons (BSE) images have been acquired at the scanning electron microscope (SEM), in order to identify the plagioclase phenocrysts suitable to be analyzed successively, selected among those that best display their zoning. After a careful observation of the BSE images, major-, minor- and selected trace element contents have been determined through combined energy-dispersive and wavelength-dispersive system electron microprobe analyses (EDS-WDS-EMPA) on transects crossing the growth zones of the selected phenocrysts. This methodology has allowed reconstructing the diffusion profile of some key-elements through the growth zones of the investigated phenocrysts. Successively, the diffusion profiles have been combined with textural features obtained through BSE images in order to obtain diffusion models aimed at estimating the timescales of crystals

  4. Urologic issues of the pediatric spina bifida patient: A review of the genitourinary concerns and urologic care during childhood and adolescence.

    PubMed

    Mickelson, Jennie; Cheng, Earl; Yerkes, Elizabeth

    2009-01-01

    Myelodysplasia is a complex patient problem that continues to present challenges for multidisciplinary care teams. The spectrum of bladder and bowel dysfunction created by this neurologic lesion is broad and requires long-term surveillance of these organ systems. This review outlines the diagnosis and management of urologic issues of the spina bifida patient throughout infancy, childhood and adolescence. Specifically, examining different approaches to care of these patients (proactive vs reactive), quality of life issues and medical and surgical management options and decision-making at each phase of life.

  5. Cotransplantation with specific populations of spina bifida bone marrow stem/progenitor cells enhances urinary bladder regeneration.

    PubMed

    Sharma, Arun K; Bury, Matthew I; Fuller, Natalie J; Marks, Andrew J; Kollhoff, David M; Rao, Manoj V; Hota, Partha V; Matoka, Derek J; Edassery, Seby L; Thaker, Hatim; Sarwark, John F; Janicki, Joseph A; Ameer, Guillermo A; Cheng, Earl Y

    2013-03-05

    Spina bifida (SB) patients afflicted with myelomeningocele typically possess a neurogenic urinary bladder and exhibit varying degrees of bladder dysfunction. Although surgical intervention in the form of enterocystoplasty is the current standard of care in which to remedy the neurogenic bladder, it is still a stop-gap measure and is associated with many complications due to the use of bowel as a source of replacement tissue. Contemporary bladder tissue engineering strategies lack the ability to reform bladder smooth muscle, vasculature, and promote peripheral nerve tissue growth when using autologous populations of cells. Within the context of this study, we demonstrate the role of two specific populations of bone marrow (BM) stem/progenitor cells used in combination with a synthetic elastomeric scaffold that provides a unique and alternative means to current bladder regeneration approaches. In vitro differentiation, gene expression, and proliferation are similar among donor mesenchymal stem cells (MSCs), whereas poly(1,8-octanediol-cocitrate) scaffolds seeded with SB BM MSCs perform analogously to control counterparts with regard to bladder smooth muscle wall formation in vivo. SB CD34(+) hematopoietic stem/progenitor cells cotransplanted with donor-matched MSCs cause a dramatic increase in tissue vascularization as well as an induction of peripheral nerve growth in grafted areas compared with samples not seeded with hematopoietic stem/progenitor cells. Finally, MSC/CD34(+) grafts provided the impetus for rapid urothelium regeneration. Data suggest that autologous BM stem/progenitor cells may be used as alternate, nonpathogenic cell sources for SB patient-specific bladder tissue regeneration in lieu of current enterocystoplasty procedures and have implications for other bladder regenerative therapies.

  6. Inpatient and Emergency Room Visits for Adolescents and Young Adults With Spina Bifida Living in South Carolina

    PubMed Central

    Mann, Joshua R.; Royer, Julie A.; Turk, Margaret A.; McDermott, Suzanne; Holland, Margaret M.; Ozturk, Orgul D.; Hardin, James W.; Thibadeau, Judy K.

    2015-01-01

    Objective To compare emergency room (ER) and inpatient hospital (IP) use rates for persons with spina bifida (SB) to peers without SB, when transition from pediatric to adult health care is likely to occur; and to analyze those ER and IP rates by age, race, socioeconomic status, gender, and type of residential area. Design A retrospective cohort study. Setting Secondary data analysis in South Carolina. Participants We studied individuals who were between 15 and 24 years old and enrolled in the State Health Plan (SHP) or state Medicaid during the 2000–2010 study period. Methods Individuals with SB were identified using ICD-9 billing codes (741.0, 741.9) in SHP, Medicaid, and hospital uniform billing (UB) data. ER and IP encounters were identified using UB data. Multivariable Generalized Estimating Equation (GEE) Poisson models were estimated to compare rates of ER and IP use among the SB group to the comparison group. Main Outcome Measures Total ER rate and IP rate, in addition to cause-specific rates for ambulatory care sensitive conditions (ACSC) and other condition categories. Results We found higher rates of ER and IP use in persons with SB compared to the control group. Among individuals with SB, young adults (those 20–24 years old) had higher rates of ER use due to all ACSC (P = .023), other ACSC (P = .04), and urinary tract infections (UTI; P = .002) compared to adolescents (those 15–19 years old). Conclusions Young adulthood is associated with increased ER use overall, as well as in specific condition categories (most notably UTI) in individuals 15–24 years old with SB. This association may be indicative of changing healthcare access as people with SB move from adolescent to adult health care, and/or physiologic changes during the age range studied. PMID:25511690

  7. The analgesic efficacy of pre-operative bilateral erector spinae plane (ESP) blocks in patients having ventral hernia repair.

    PubMed

    Chin, K J; Adhikary, S; Sarwani, N; Forero, M

    2017-04-01

    Laparoscopic ventral hernia repair is an operation associated with significant postoperative pain, and regional anaesthetic techniques are of potential benefit. The erector spinae plane (ESP) block performed at the level of the T5 transverse process has recently been described for thoracic surgery, and we hypothesised that performing the ESP block at a lower vertebral level would provide effective abdominal analgesia. We performed pre-operative bilateral ESP blocks with 20-30 ml ropivacaine 0.5% at the level of the T7 transverse process in four patients undergoing laparoscopic ventral hernia repair. Median (range) 24-h opioid consumption was 18.7 mg (0.0-43.0 mg) oral morphine. The highest and lowest median (range) pain scores in the first 24 h were 3.5 (3.0-5.0) and 2.5 (0.0-3.0) on an 11-point numerical rating scale. We also performed the block in a fresh cadaver and assessed the extent of injectate spread using computerised tomography. There was radiographic evidence of spread extending cranially to the upper thoracic levels and caudally as far as the L2-L3 transverse processes. We conclude that the ESP block is a promising regional anaesthetic technique for laparoscopic ventral hernia repair and other abdominal surgery when performed at the level of the T7 transverse process. Its advantages are the ability to block both supra-umbilical and infra-umbilical dermatomes with a single-level injection and its relative simplicity.

  8. PAX genes and human neural tube defects: an amino acid substitution in PAX1 in a patient with spina bifida.

    PubMed Central

    Hol, F A; Geurds, M P; Chatkupt, S; Shugart, Y Y; Balling, R; Schrander-Stumpel, C T; Johnson, W G; Hamel, B C; Mariman, E C

    1996-01-01

    From studies in the mouse and from the clinical and molecular analysis of patients with type 1 Waardenburg syndrome, particular members of the PAX gene family are suspected factors in the aetiology of human neural tube defects (NTD). To investigate the role of PAX1, PAX3, PAX7, and PAX9, allelic association studies were performed in 79 sporadic and 38 familial NTD patients from the Dutch population. Sequence variation was studied by SSC analysis of the paired domain regions of the PAX1, PAX7, and PAX9 genes and of the complete PAX3 gene. In one patient with spina bifida, a mutation in the PAX1 gene was detected changing the conserved amino acid Gln to His at position 42 in the paired domain of the protein. The mutation was inherited through the maternal line from the unaffected grandmother and was not detected in 300 controls. In the PAX3 gene, variation was detected at several sites including a Thr/Lys amino acid substitution in exon 6. All alleles were present among patients and controls in about the same frequencies. However, an increased frequency of the rare allele of a silent polymorphism in exon 2 was found in NTD patients, but no significant association was observed (p = 0.06). No sequence variation was observed in the paired domain of the PAX7 and PAX9 genes. Our findings so far do not support a major role of the PAX genes examined in the aetiology of NTD. However, the detection of a mutation in PAX1 suggests that, in principle, this gene can act as a risk factor for human NTD. Images PMID:8863157

  9. Copy number variation analysis implicates the cell polarity gene glypican 5 as a human spina bifida candidate gene.

    PubMed

    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

    2013-03-15

    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.

  10. In vivo lumbar erector spinae oxygenation and blood volume measurements in healthy men during seated whole-body vibration.

    PubMed

    Maikala, Rammohan V; Bhambhani, Yagesh N

    2006-09-01

    Exposure to whole-body vibration is implicated as one of the occupational risk factors for lower back disorders; however, its influence on the lumbar muscle physiology is still poorly understood. The objective of this study was to investigate the effects of backrest support and hand grip contractions on lumbar muscle oxygenation and blood volume responses during seated whole-body vibration using continuous dual-wave near-infrared spectroscopy. Thirteen healthy men were exposed to frequencies of 3, 4.5 and 6 Hz on a vibration simulator, in randomized order on separate days. Each day the duration of the protocol was 30 min. During the fifth minute of vibration 'with' and 'without' backrest support, participants performed maximal rhythmic hand grip contractions for 1 min. In general, erector spinae oxygenation and blood volume showed a trend to decrease with vibration exposure compared to the control condition. However, these responses were not influenced by the change in vibration frequency (P > 0.05). Sitting without backrest resulted in a greater decrease in oxygenation (by 27%, P = 0.02) and blood volume (by 11%, P = 0.05) than with backrest, implying a deficiency in oxygen supply owing to the sitting posture. Compared to the vibration-only condition, hand grip work decreased both oxygenation (by 22%, P = 0.003) and blood volume responses (by 13%, P = 0.04), suggesting that postural load due to prolonged sitting combined with physical activity during vibration might further burden paraspinal muscles. The influence of adipose tissue thickness of the lumbar muscle on optically derived oxygenation and blood volume changes was inconclusive.

  11. 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

  12. 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

  13. Structural mapping of Maxwell Montes

    NASA Technical Reports Server (NTRS)

    Keep, Myra; Hansen, Vicki L.

    1993-01-01

    Four sets of structures were mapped in the western and southern portions of Maxwell Montes. An early north-trending set of penetrative lineaments is cut by dominant, spaced ridges and paired valleys that trend northwest. To the south the ridges and valleys splay and graben form in the valleys. The spaced ridges and graben are cut by northeast-trending graben. The northwest-trending graben formed synchronously with or slightly later than the spaced ridges. Formation of the northeast-trending graben may have overlapped with that of the northwest-trending graben, but occurred in a spatially distinct area (regions of 2 deg slope). Graben formation, with northwest-southeast extension, may be related to gravity-sliding. Individually and collectively these structures are too small to support the immense topography of Maxwell, and are interpreted as parasitic features above a larger mass that supports the mountain belt.

  14. Challenges of Monte Carlo Transport

    SciTech Connect

    Long, Alex Roberts

    2016-06-10

    These are slides from a presentation for Parallel Summer School at Los Alamos National Laboratory. Solving discretized partial differential equations (PDEs) of interest can require a large number of computations. We can identify concurrency to allow parallel solution of discrete PDEs. Simulated particles histories can be used to solve the Boltzmann transport equation. Particle histories are independent in neutral particle transport, making them amenable to parallel computation. Physical parameters and method type determine the data dependencies of particle histories. Data requirements shape parallel algorithms for Monte Carlo. Then, Parallel Computational Physics and Parallel Monte Carlo are discussed and, finally, the results are given. The mesh passing method greatly simplifies the IMC implementation and allows simple load-balancing. Using MPI windows and passive, one-sided RMA further simplifies the implementation by removing target synchronization. The author is very interested in implementations of PGAS that may allow further optimization for one-sided, read-only memory access (e.g. Open SHMEM). The MPICH_RMA_OVER_DMAPP option and library is required to make one-sided messaging scale on Trinitite - Moonlight scales poorly. Interconnect specific libraries or functions are likely necessary to ensure performance. BRANSON has been used to directly compare the current standard method to a proposed method on idealized problems. The mesh passing algorithm performs well on problems that are designed to show the scalability of the particle passing method. BRANSON can now run load-imbalanced, dynamic problems. Potential avenues of improvement in the mesh passing algorithm will be implemented and explored. A suite of test problems that stress DD methods will elucidate a possible path forward for production codes.

  15. 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.

  16. Inter-tester reliability and precision of manual muscle testing and hand-held dynamometry in lower limb muscles of children with spina bifida.

    PubMed

    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 therapists and a student physical therapist. Inter-tester reliability [ICC(2,1)] for HHD varied from 0.76 to 0.83, indicating excellent reliability for the three muscle groups. Inter-tester reliability for MMT was 0.75 for the hip abductor muscle group, indicating good reliability, and 0.37 to 0.40 for the remaining muscle groups. The minimum detectable change was 15N for HHD and 1 scale unit of a 0 to 5 MMT scale. The results suggest a situation-specific solution to the question of which method to use. To detect small strength changes over time in children with spina bifida, MMT should be used when the child has insufficient strength to move the limb against gravity; otherwise, HHD should be used.

  17. Amino acid sequence similarity of Hev b 3 to two previously reported 27- and 23-kDa latex proteins allergenic to spina bifida patients.

    PubMed

    Yeang, H Y; Ward, M A; Zamri, A S; Dennis, M S; Light, D R

    1998-05-01

    Separate studies have reported spina bifida patients to be especially allergic to proteins of 27 and 23 kDa found in the serum of centrifuged natural rubber latex. An insoluble latex protein located on the surface of small rubber particles, Hev b 3, has similarly been found to be allergenic to spina bifida patients. In this study, internal amino acid sequences of Hev b 3 showed similarity to the published sequences for the 27- and 23-kDa latex proteins. The latter allergens are hence identified as Hev b 3. Determination of the molecular weight of Hev b 3 revealed various species of 22-23 kDa. The consistent gaps of about 266 Da observed between various forms of the intact protein suggest that the protein undergoes post-translational modification. To determine whether Hev b 3 also occurs in a soluble form in the latex serum, its presence in molecular-filtered serum was checked by ELISA and Western blot. The results showed Hev b 3 to be largely absent in the C-serum from fresh latex. The protein is therefore insoluble in its native state. However, a small amount of the solubilized protein was detected in ammonia-stabilized latex (commonly used in the manufacture of latex products).

  18. [Vascular diseases, spina bifida and schizophrenia in a single family associated with the heterozygote mutation of the heat-sensitive variant of methylenetetrahydrofolate reductase].

    PubMed

    Horváth, A; Morava, E; Tóth, G; Czakó, M; Melegh, B; Kosztolányi, G

    2001-07-08

    Homozygous mutation of the thermolabile variant of methylene tetrahydrofolate reductase (MTHFR) may result in hyperhomocystinemia, leading to an increased risk for early cardiovascular disease, neural tube defects, and possibly major depression, schizophrenia. According to recent studies heterozygosity for the thermolabile variant of the MTHFR gene mutation is also more frequent in patients with thrombotic disease compared to that in the average population. We report on a family with different types of early vascular disease. In four consecutive generations MTHFR heterozygosity was detected: in the proband and in her mother, grandfather and daughter. Further conditions of the family members, possibly due to carrying the mutation, came to light by the pedigree analysis and examinations. The patient had pulmonary emboli at young age, her aunt died of spina bifida shortly after birth. The patient's mother suffers from schizophrenia and depression. The grandfather had pulmonary emboli, her sister with spina bifida occulta also carries the same mutation, as does her daughter who is sofar asymptomatic. In other asymptomatic members of the family no mutations were found. Unexpectedly, hyperhomocystinemia was detected in all heterozygote individuals. Our study demonstrates the necessity for folic acid therapy in mutation carriers to prevent early vascular events, depression and schizophrenia, and also to reduce the risk for neural tube defects in a preconception setting.

  19. Large subcapsular hematoma following ureteroscopic laser lithotripsy of renal calculi in a spina bifida patient: lessons we learn

    PubMed Central

    Vaidyanathan, Subramanian; Samsudin, Azi; Singh, Gurpreet; Hughes, Peter L; Soni, Bakul M; Selmi, Fahed

    2016-01-01

    Introduction Paraplegic patients are at greater risk of developing complications following ureteroscopic lithotripsy because of urine infection associated with neuropathic bladder, difficulties in access due to altered anatomy of urinary bladder and urethra, spinal curvature, spasticity, and contractures. We report the occurrence of large subcapsular hematoma following ureteroscopy and discuss lessons we learn from this case. Case report A 48-year-old male patient with spina bifida underwent ureteroscopy with laser lithotripsy and ureteric stenting for left ureteric stone and staghorn calculus with hydronephrosis; laser lithotripsy was repeated after 3 months; both procedures were performed by a senior urologist and did not result in any complications. Ureteroscopic laser lithotripsy was performed 5 months later by a urological trainee; it was difficult to negotiate the scope as vision became poor because of bleeding (as a result of the procedure). Postoperatively, hematuria persisted; temperature was 39°C. Cefuroxime was given intravenously followed by gentamicin for 5 days; hematuria subsided gradually; he was discharged home. Ten days later, this patient developed temperature, the urine culture grew Pseudomonas aeruginosa, and ciprofloxacin was given orally. Computed tomography (CT) of the urinary tract, performed 4 weeks after ureteroscopy, revealed a 9×7 cm subcapsular collection on the left kidney compressing underlying parenchyma. Percutaneous drainage was not feasible because of severe curvature of spine. Isotope renogram revealed deterioration in left renal function from 30% to 17%. Follow-up CT revealed reduction in the size of subcapsular hematoma, no hydronephrosis, and several residual calculi. Conclusion Risk of subcapsular hematoma following ureteroscopic lithotripsy can be reduced by avoiding prolonged endoscopy and performing ureteroscopy under low pressure. When a paraplegic patient develops features of infection after ureteroscopy, renal

  20. Prevalence of Spina Bifida Occulta and Its Relationship With Overactive Bladder in Middle-Aged and Elderly Chinese People

    PubMed Central

    2016-01-01

    Purpose: To investigate the prevalence of spina bifida occulta (SBO) and its relationship with the presence of overactive bladder (OAB) in middle-aged and elderly people in China. Methods: A cross-sectional community-based survey was carried out at 7 communities in Zhengzhou City, China from December 15, 2013 to June 10, 2014, where residents aged over 40 years were randomly selected to participate. All of the participants underwent lumbosacral radiographic analysis and relevant laboratory tests. A questionnaire including basic information, past medical history and present illness, and the OAB symptom score was filled out by all participants. Chi-square tests and logistic regression were used for data analysis with a P-value of <0.05 denoting statistical significance. Results: A total of 1,061 subjects were qualified for the final statistical analysis (58.8±11.7 years; male, 471 [44.4%]; female, 590 [55.6%]). The overall prevalence of SBO was 15.1% (160 of 1,061): 18.3% (86 of 471) in men and 12.5% (74 of 590) in women. Among these subjects, 13.7% (145 of 1,061) had OAB: 13.2% (62 of 471) in men and 14.1% (83 of 590) in women. The results of logistic regression showed that age, SBO, history of cerebral infarction (HCI), and constipation were risk factors for OAB (P<0.05), while sex, history of childhood enuresis (HCE), body mass index (BMI), and diabetes mellitus (DM) were not (P>0.05). In men, age, SBO, and constipation were risk factors for OAB (P<0.05), while HCE, BMI, DM, HCI, and benign prostate hyperplasia were not (P>0.05). In women, age, SBO, and HCI were risk factors for OAB (P<0.05), while HCE, BMI, DM, vaginal delivery, and constipation were not (P>0.05). Conclusions: The prevalence of SBO is high and it is related to OAB in middle-aged and elderly people in China. PMID:27377948

  1. The transition process of spina bifida patients to adult-centred care: An assessment of the Canadian urology landscape

    PubMed Central

    Wajchendler, Amy; Anderson, Peter; Koyle, Martin A.

    2017-01-01

    Introduction: Due to medical advances over the past three decades, the vast majority of children with spina bifida (SB) now survive into adulthood. As a result, there is a need to implement a well-defined urological transition process for these patients from the pediatric to adult environment. The objective of this study was to identify and analyze the current medical practices employed and the attitudes regarding transition by Canadian pediatric urologists caring for the SB population. Methods: A survey consisting of 14 questions pertaining to physician demographics, current practice, and attitudes towards the transition process of SB patients was distributed at the 2015 annual Pediatric Urologists of Canada (PUC) conference. The survey respondents remained anonymous, and the data were collected and analyzed. Results: A total of 28 surveys were collected from urologists across Canada (25 full-time pediatric, three also providing adult care), representing a >75% response rate. The transition process was suggested to begin at the age of 18 or older by 43% (12/28) of pediatric urologists. The majority, 86% (24/28), do not currently use a questionnaire or a checklist to determine transition readiness of patients. Forty-six percent (13/28) of pediatric urologists do not provide ongoing urological care to their patients after referral has been made to adult-centred care. In the province of Ontario, in which 39% (11/28) of the pediatric urologists practice, 82% (9/11) are full-time pediatric urologists and 78% (7/9) do not provide ongoing care to SB patients after the age of 18. Conclusions: A significant minority of Canadian pediatric urologists perceive that the transition process should begin at the age of 18 or older. As such, it can be inferred that transfer of care and transition are synonymous, not independent. Simplistically, this suggests that transition represents an event rather than a longitudinal process. The fact there is no defined ongoing urological care

  2. Reflex pathways connect receptors in the human lower leg to the erector spinae muscles of the lower back.

    PubMed

    Clair, J M; Okuma, Y; Misiaszek, J E; Collins, D F

    2009-06-01

    Reflex pathways connect all four limbs in humans. Presently, we tested the hypothesis that reflexes also link sensory receptors in the lower leg with muscles of the lower back (erector spinae; ES). Taps were applied to the right Achilles' tendon and electromyographic activity was recorded from the right soleus and bilaterally from ES. Reflexes were compared between sitting and standing and between standing with the eyes open versus closed. Reflexes were evoked bilaterally in ES and consisted of an early latency excitation, a medium latency inhibition, and a longer latency excitation. During sitting but not standing, the early excitation was larger in the ES muscle ipsilateral to the stimulation (iES) than in the contralateral ES (cES). During standing but not sitting, the longer latency excitation in cES was larger than in iES. This response in cES was also larger during standing compared to sitting. Responses were not significantly different between the eyes open and eyes closed conditions. Taps applied to the lateral calcaneus (heel taps) evoked responses in ES that were not significantly different in amplitude or latency than those evoked by tendon taps, despite a 75-94% reduction in the amplitude of the soleus stretch reflex evoked by the heel taps. Electrical stimulation of the sural nerve, a purely cutaneous nerve at the ankle, evoked ES reflexes that were not significantly different in amplitude but had significantly longer latencies than those evoked by the tendon and heel taps. These results support the hypothesis that reflex pathways connect receptors in the lower leg with muscles of the lower back and show that that the amplitude of these reflexes is modulated by task. Responses evoked by stimulation of the sural nerve establish that reflex pathways connect the ES muscles with cutaneous receptors of the foot. In contrast, the large volley in muscle spindle afferents induced by the tendon taps compared to the heel taps did not alter the ES responses

  3. Monte Carlo Shower Counter Studies

    NASA Technical Reports Server (NTRS)

    Snyder, H. David

    1991-01-01

    Activities and accomplishments related to the Monte Carlo shower counter studies are summarized. A tape of the VMS version of the GEANT software was obtained and installed on the central computer at Gallaudet University. Due to difficulties encountered in updating this VMS version, a decision was made to switch to the UNIX version of the package. This version was installed and used to generate the set of data files currently accessed by various analysis programs. The GEANT software was used to write files of data for positron and proton showers. Showers were simulated for a detector consisting of 50 alternating layers of lead and scintillator. Each file consisted of 1000 events at each of the following energies: 0.1, 0.5, 2.0, 10, 44, and 200 GeV. Data analysis activities related to clustering, chi square, and likelihood analyses are summarized. Source code for the GEANT user subprograms and data analysis programs are provided along with example data plots.

  4. 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.

  5. Extra Chance Generalized Hybrid Monte Carlo

    NASA Astrophysics Data System (ADS)

    Campos, Cédric M.; Sanz-Serna, J. M.

    2015-01-01

    We study a method, Extra Chance Generalized Hybrid Monte Carlo, to avoid rejections in the Hybrid Monte Carlo method and related algorithms. In the spirit of delayed rejection, whenever a rejection would occur, extra work is done to find a fresh proposal that, hopefully, may be accepted. We present experiments that clearly indicate that the additional work per sample carried out in the extra chance approach clearly pays in terms of the quality of the samples generated.

  6. Error in Monte Carlo, quasi-error in Quasi-Monte Carlo

    NASA Astrophysics Data System (ADS)

    Kleiss, Ronald; Lazopoulos, Achilleas

    2006-07-01

    While the Quasi-Monte Carlo method of numerical integration achieves smaller integration error than standard Monte Carlo, its use in particle physics phenomenology has been hindered by the absence of a reliable way to estimate that error. The standard Monte Carlo error estimator relies on the assumption that the points are generated independently of each other and, therefore, fails to account for the error improvement advertised by the Quasi-Monte Carlo method. We advocate the construction of an estimator of stochastic nature, based on the ensemble of pointsets with a particular discrepancy value. We investigate the consequences of this choice and give some first empirical results on the suggested estimators.

  7. Monte Carlo docking with ubiquitin.

    PubMed Central

    Cummings, M. D.; Hart, T. N.; Read, R. J.

    1995-01-01

    The development of general strategies for the performance of docking simulations is prerequisite to the exploitation of this powerful computational method. Comprehensive strategies can only be derived from docking experiences with a diverse array of biological systems, and we have chosen the ubiquitin/diubiquitin system as a learning tool for this process. Using our multiple-start Monte Carlo docking method, we have reconstructed the known structure of diubiquitin from its two halves as well as from two copies of the uncomplexed monomer. For both of these cases, our relatively simple potential function ranked the correct solution among the lowest energy configurations. In the experiments involving the ubiquitin monomer, various structural modifications were made to compensate for the lack of flexibility and for the lack of a covalent bond in the modeled interaction. Potentially flexible regions could be identified using available biochemical and structural information. A systematic conformational search ruled out the possibility that the required covalent bond could be formed in one family of low-energy configurations, which was distant from the observed dimer configuration. A variety of analyses was performed on the low-energy dockings obtained in the experiment involving structurally modified ubiquitin. Characterization of the size and chemical nature of the interface surfaces was a powerful adjunct to our potential function, enabling us to distinguish more accurately between correct and incorrect dockings. Calculations with the structure of tetraubiquitin indicated that the dimer configuration in this molecule is much less favorable than that observed in the diubiquitin structure, for a simple monomer-monomer pair. Based on the analysis of our results, we draw conclusions regarding some of the approximations involved in our simulations, the use of diverse chemical and biochemical information in experimental design and the analysis of docking results, as well as

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

    PubMed

    English, Lianne; Barnes, Marcia A; Fletcher, Jack M; Dennis, Maureen; Raghubar, Kimberly P

    2010-05-01

    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.

  9. Individual Adjustment, Parental Functioning, and Perceived Social Support in Hispanic and Non-Hispanic White Mothers and Fathers of Children With Spina Bifida

    PubMed Central

    Devine, Katie A.; Holbein, Christina E.; Psihogios, Alexandra M.; Amaro, Christina M.

    2012-01-01

    Objective To compare Hispanic and non-Hispanic White mothers and fathers of children with spina bifida on measures of individual adjustment, parental functioning, and perceived social support. Method Mothers (29 Hispanic, 79 non-Hispanic White) and fathers (26 Hispanic, 68 non-Hispanic White) completed questionnaires regarding psychological distress, parental functioning, and perceived social support. Results Mothers and fathers reported similar individual adjustment across groups. Hispanic mothers reported lower levels of parenting satisfaction, competence as a parent, and social support, as well as higher perceptions of child vulnerability. Hispanic fathers reported lower levels of parenting satisfaction and higher perceptions of child vulnerability. Effect sizes were reduced when socioeconomic status was included as a covariate. Conclusions Hispanic parents, particularly mothers, are at risk for lower feelings of satisfaction and competence as parents. More research is needed to understand cultural factors related to these differences. PMID:21990583

  10. Antifungal activity of nettle (Urtica dioica L.), colocynth (Citrullus colocynthis L. Schrad), oleander (Nerium oleander L.) and konar (Ziziphus spina-christi L.) extracts on plants pathogenic fungi.

    PubMed

    Hadizadeh, I; Peivastegan, B; Kolahi, M

    2009-01-01

    Anti-mycotic activity of the ethanol extracts from Nettle (Urtica dioica L.), Colocynth (Citrullus colocynthis L. Schrad), Konar (Ziziphus spina-christi L.) and Oleander (Nerium oleander L.) floral parts were screened in vitro against four important plant pathogenic fungi viz.; Alternaria alternate, Fusarium oxysporum, Fusarium solani and Rizoctonia solani using agar dilution bioassay. Extracts showed antifungal activity against all the tested fungi. Among the plants, Nettle and Colocynth were the most effective against A. alternate and R. solani while Oleander possesses the best inhibition on F. oxysporum and F. solani. Konar was the most effective extract by reducing the growth of Rizoctonia solani than other fungi. These results showed that extracts could be considered suitable alternatives to chemical additives for the control of fungal diseases in plants.

  11. Electronic structure quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Bajdich, Michal; Mitas, Lubos

    2009-04-01

    Quantum Monte Carlo (QMC) is an advanced simulation methodology for studies of manybody quantum systems. The QMC approaches combine analytical insights with stochastic computational techniques for efficient solution of several classes of important many-body problems such as the stationary Schrödinger equation. QMC methods of various flavors have been applied to a great variety of systems spanning continuous and lattice quantum models, molecular and condensed systems, BEC-BCS ultracold condensates, nuclei, etc. In this review, we focus on the electronic structure QMC, i.e., methods relevant for systems described by the electron-ion Hamiltonians. Some of the key QMC achievements include direct treatment of electron correlation, accuracy in predicting energy differences and favorable scaling in the system size. Calculations of atoms, molecules, clusters and solids have demonstrated QMC applicability to real systems with hundreds of electrons while providing 90-95% of the correlation energy and energy differences typically within a few percent of experiments. Advances in accuracy beyond these limits are hampered by the so-called fixed-node approximation which is used to circumvent the notorious fermion sign problem. Many-body nodes of fermion states and their properties have therefore become one of the important topics for further progress in predictive power and efficiency of QMC calculations. Some of our recent results on the wave function nodes and related nodal domain topologies will be briefly reviewed. This includes analysis of few-electron systems and descriptions of exact and approximate nodes using transformations and projections of the highly-dimensional nodal hypersurfaces into the 3D space. Studies of fermion nodes offer new insights into topological properties of eigenstates such as explicit demonstrations that generic fermionic ground states exhibit the minimal number of two nodal domains. Recently proposed trial wave functions based on Pfaffians with

  12. Trunk Muscle Characteristics of the Multifidi, Erector Spinae, Psoas, and Quadratus Lumborum in Older Adults With and Without Chronic Low Back Pain.

    PubMed

    Sions, J Megan; Elliott, James M; Pohlig, Ryan T; Hicks, Gregory E

    2017-03-01

    Study Design Cross-sectional study. Objective To determine whether there are differences in trunk muscle characteristics between older adults with and without chronic low back pain (LBP), while controlling for age, sex, and body mass index. Background Muscle support for the trunk is provided by the multifidi, erector spinae, psoas, and quadratus lumborum. Trunk muscle characteristics may be altered with aging and/or chronic LBP. To date, most trunk muscle research has been conducted among younger adults. Given age-related muscle changes, such as reduced size and increased intramuscular fat, studies are needed in older adults, including those comparing older adults with and without LBP. Methods One hundred two older adults with (n = 53) and without (n = 49) chronic LBP were included. Cross-sectional area (CSA) measurements were taken by tracing inside the fascial borders on magnetic resonance images. Pixel intensity summaries were obtained to compute muscle-to-fat indices and relative muscle CSA, that is, CSA void of fat. Right/left averages for levels L2 through L5 were determined. Mixed-design analyses of covariance were used to test for differences between groups, based on LBP presence and sex, across levels (P≤.05). Results Older adults with LBP had a greater average multifidus muscle-to-fat index (0.51 versus 0.49) and smaller average erector spinae relative muscle CSA (8.56 cm(2) versus 9.26 cm(2)) when compared to control participants without LBP. No interactions between LBP status and average muscle characteristics were found for the psoas or quadratus lumborum (P>.05). Conclusion Up to 54% of older adult trunk muscle CSA may be fat. Women have smaller muscles and greater intramuscular fat (at lower spinal levels) than men. J Orthop Sports Phys Ther 2017;47(3):173-179. Epub 3 Feb 2017. doi:10.2519/jospt.2017.7002.

  13. 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.

  14. Spina Bifida Clinic Directory

    MedlinePlus

    ... Development (pediatric and adult) 100 Hawkins Drive Iowa City, IA 52242-1011 (877) 686-0031 (319) 353- ... Clinic (pediatric and adult) 3901 Rainbow Blvd., Kansas City, KS 66160 (913) 588-5939 Email: astanton@kumc. ...

  15. Hypertension and Spina Bifida

    MedlinePlus

    ... a standard workup. www.spinabildaassociation.org • 1600 Wilson Blvd. Suite 800 Arlington, VA 22209 • 800-621-3141 ... an individual basis. www.spinabildaassociation.org • 1600 Wilson Blvd. Suite 800 Arlington, VA 22209 • 800-621-3141

  16. Spina Bifida Occulta

    MedlinePlus

    ... stretched and damaged. www.spinabildaassociation.org • 1600 Wilson Blvd. Suite 800 Arlington, VA 22209 • 800-621-3141 ... an individual basis. www.spinabildaassociation.org • 1600 Wilson Blvd. Suite 800 Arlington, VA 22209 • 800-621-3141

  17. 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.

  18. Self-learning Monte Carlo method

    NASA Astrophysics Data System (ADS)

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

    2017-01-01

    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. We demonstrate the efficiency of SLMC in a spin model at the phase transition point, achieving a 10-20 times speedup.

  19. Adiabatic optimization versus diffusion Monte Carlo methods

    NASA Astrophysics Data System (ADS)

    Jarret, Michael; Jordan, Stephen P.; Lackey, Brad

    2016-10-01

    Most experimental and theoretical studies of adiabatic optimization use stoquastic Hamiltonians, whose ground states are expressible using only real nonnegative amplitudes. This raises a question as to whether classical Monte Carlo methods can simulate stoquastic adiabatic algorithms with polynomial overhead. Here we analyze diffusion Monte Carlo algorithms. We argue that, based on differences between L1 and L2 normalized states, these algorithms suffer from certain obstructions preventing them from efficiently simulating stoquastic adiabatic evolution in generality. In practice however, we obtain good performance by introducing a method that we call Substochastic Monte Carlo. In fact, our simulations are good classical optimization algorithms in their own right, competitive with the best previously known heuristic solvers for MAX-k -SAT at k =2 ,3 ,4 .

  20. 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

  1. Monte Carlo inversion of seismic data

    NASA Technical Reports Server (NTRS)

    Wiggins, R. A.

    1972-01-01

    The analytic solution to the linear inverse problem provides estimates of the uncertainty of the solution in terms of standard deviations of corrections to a particular solution, resolution of parameter adjustments, and information distribution among the observations. It is shown that Monte Carlo inversion, when properly executed, can provide all the same kinds of information for nonlinear problems. Proper execution requires a relatively uniform sampling of all possible models. The expense of performing Monte Carlo inversion generally requires strategies to improve the probability of finding passing models. Such strategies can lead to a very strong bias in the distribution of models examined unless great care is taken in their application.

  2. Parallel Markov chain Monte Carlo simulations.

    PubMed

    Ren, Ruichao; Orkoulas, G

    2007-06-07

    With strict detailed balance, parallel Monte Carlo simulation through domain decomposition cannot be validated with conventional Markov chain theory, which describes an intrinsically serial stochastic process. In this work, the parallel version of Markov chain theory and its role in accelerating Monte Carlo simulations via cluster computing is explored. It is shown that sequential updating is the key to improving efficiency in parallel simulations through domain decomposition. A parallel scheme is proposed to reduce interprocessor communication or synchronization, which slows down parallel simulation with increasing number of processors. Parallel simulation results for the two-dimensional lattice gas model show substantial reduction of simulation time for systems of moderate and large size.

  3. Interaction picture density matrix quantum Monte Carlo

    SciTech Connect

    Malone, Fionn D. Lee, D. K. K.; Foulkes, W. M. C.; Blunt, N. S.; Shepherd, James J.; Spencer, J. S.

    2015-07-28

    The recently developed density matrix quantum Monte Carlo (DMQMC) algorithm stochastically samples the N-body thermal density matrix and hence provides access to exact properties of many-particle quantum systems at arbitrary temperatures. We demonstrate that moving to the interaction picture provides substantial benefits when applying DMQMC to interacting fermions. In this first study, we focus on a system of much recent interest: the uniform electron gas in the warm dense regime. The basis set incompleteness error at finite temperature is investigated and extrapolated via a simple Monte Carlo sampling procedure. Finally, we provide benchmark calculations for a four-electron system, comparing our results to previous work where possible.

  4. 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.

  5. 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

  6. Parallel Markov chain Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Ren, Ruichao; Orkoulas, G.

    2007-06-01

    With strict detailed balance, parallel Monte Carlo simulation through domain decomposition cannot be validated with conventional Markov chain theory, which describes an intrinsically serial stochastic process. In this work, the parallel version of Markov chain theory and its role in accelerating Monte Carlo simulations via cluster computing is explored. It is shown that sequential updating is the key to improving efficiency in parallel simulations through domain decomposition. A parallel scheme is proposed to reduce interprocessor communication or synchronization, which slows down parallel simulation with increasing number of processors. Parallel simulation results for the two-dimensional lattice gas model show substantial reduction of simulation time for systems of moderate and large size.

  7. Monte Carlo simulation of neutron scattering instruments

    SciTech Connect

    Seeger, P.A.

    1995-12-31

    A library of Monte Carlo subroutines has been developed for the purpose of design of neutron scattering instruments. Using small-angle scattering as an example, the philosophy and structure of the library are described and the programs are used to compare instruments at continuous wave (CW) and long-pulse spallation source (LPSS) neutron facilities. The Monte Carlo results give a count-rate gain of a factor between 2 and 4 using time-of-flight analysis. This is comparable to scaling arguments based on the ratio of wavelength bandwidth to resolution width.

  8. 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.

  9. Scalable Domain Decomposed Monte Carlo Particle Transport

    SciTech Connect

    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.

  10. Monte Carlo Simulation of Counting Experiments.

    ERIC Educational Resources Information Center

    Ogden, Philip M.

    A computer program to perform a Monte Carlo simulation of counting experiments was written. The program was based on a mathematical derivation which started with counts in a time interval. The time interval was subdivided to form a binomial distribution with no two counts in the same subinterval. Then the number of subintervals was extended to…

  11. A comparison of Monte Carlo generators

    SciTech Connect

    Golan, Tomasz

    2015-05-15

    A comparison of GENIE, NEUT, NUANCE, and NuWro Monte Carlo neutrino event generators is presented using a set of four observables: protons multiplicity, total visible energy, most energetic proton momentum, and π{sup +} two-dimensional energy vs cosine distribution.

  12. Monte Carlo studies of uranium calorimetry

    SciTech Connect

    Brau, J.; Hargis, H.J.; Gabriel, T.A.; Bishop, B.L.

    1985-01-01

    Detailed Monte Carlo calculations of uranium calorimetry are presented which reveal a significant difference in the responses of liquid argon and plastic scintillator in uranium calorimeters. Due to saturation effects, neutrons from the uranium are found to contribute only weakly to the liquid argon signal. Electromagnetic sampling inefficiencies are significant and contribute substantially to compensation in both systems. 17 references.

  13. 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)

  14. Search and Rescue Monte Carlo Simulation.

    DTIC Science & Technology

    1985-03-01

    confidence interval ) of the number of lives saved. A single page output and computer graphic present the information to the user in an easily understood...format. The confidence interval can be reduced by making additional runs of this Monte Carlo model. (Author)

  15. Monte Carlo methods in genetic analysis

    SciTech Connect

    Lin, Shili

    1996-12-31

    Many genetic analyses require computation of probabilities and likelihoods of pedigree data. With more and more genetic marker data deriving from new DNA technologies becoming available to researchers, exact computations are often formidable with standard statistical methods and computational algorithms. The desire to utilize as much available data as possible, coupled with complexities of realistic genetic models, push traditional approaches to their limits. These methods encounter severe methodological and computational challenges, even with the aid of advanced computing technology. Monte Carlo methods are therefore increasingly being explored as practical techniques for estimating these probabilities and likelihoods. This paper reviews the basic elements of the Markov chain Monte Carlo method and the method of sequential imputation, with an emphasis upon their applicability to genetic analysis. Three areas of applications are presented to demonstrate the versatility of Markov chain Monte Carlo for different types of genetic problems. A multilocus linkage analysis example is also presented to illustrate the sequential imputation method. Finally, important statistical issues of Markov chain Monte Carlo and sequential imputation, some of which are unique to genetic data, are discussed, and current solutions are outlined. 72 refs.

  16. Monte Carlo studies of ARA detector optimization

    NASA Astrophysics Data System (ADS)

    Stockham, Jessica

    2013-04-01

    The Askaryan Radio Array (ARA) is a neutrino detector deployed in the Antarctic ice sheet near the South Pole. The array is designed to detect ultra high energy neutrinos in the range of 0.1-10 EeV. Detector optimization is studied using Monte Carlo simulations.

  17. 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

  18. A detailed musculoskeletal study of a fetus with anencephaly and spina bifida (craniorachischisis), and comparison with other cases of human congenital malformations.

    PubMed

    Alghamdi, Malak A; Ziermann, Janine M; Gregg, Lydia; Diogo, Rui

    2017-03-07

    Few descriptions of the musculoskeletal system of humans with anencephaly or spina bifida exist in the literature. Even less is published about individuals in which both phenomena occur together, i.e. about craniorachischisis. Here we provide a detailed report on the musculoskeletal structures of a fetus with craniorachischisis, as well as comparisons with the few descriptions for anencephaly and with musculoskeletal anomalies found in other congenital malformations. We focused in particular on the comparison with trisomies 13, 18, and 21 because neural tube defects have been associated with such chromosomal defects. Our results showed that many of the defects found in the fetus with craniorachischisis are similar not only to anomalies previously described in the available works on musculoskeletal phenotypes seen in fetuses with anencephaly and spina bifida, but also to a wide range of other different conditions/syndromes including trisomies 13, 18 and 21, and cyclopia. The fact that similar anomalies are seen commonly not only in a wide range of different syndromes, but also as variants of the normal human population and as the 'normal' phenotype of other animals, supports Pere Alberch's unfortunately named idea of a 'logic of monsters'. That is, it supports the idea that development is so constrained that both in 'normal' and abnormal development one sees certain outcomes being produced again and again because ontogenetic constraints only allow a few possible outcomes, thus also leading to cases where the anatomical defects of some organisms are similar to the 'normal' phenotype of other organisms. In fact, this applies not only to specific anomalies but also to general patterns, such as the fact that in pathological conditions affecting different regions of the body, one consistently sees more defects on the upper limbs than on the lower limbs. Such general patterns are, again, seen in the fetus examined for this study, which had 29 muscle anomalies on the right

  19. Monte Carlo Particle Transport: Algorithm and Performance Overview

    SciTech Connect

    Gentile, N; Procassini, R; Scott, H

    2005-06-02

    Monte Carlo methods are frequently used for neutron and radiation transport. These methods have several advantages, such as relative ease of programming and dealing with complex meshes. Disadvantages include long run times and statistical noise. Monte Carlo photon transport calculations also often suffer from inaccuracies in matter temperature due to the lack of implicitness. In this paper we discuss the Monte Carlo algorithm as it is applied to neutron and photon transport, detail the differences between neutron and photon Monte Carlo, and give an overview of the ways the numerical method has been modified to deal with issues that arise in photon Monte Carlo simulations.

  20. An enhanced Monte Carlo outlier detection method.

    PubMed

    Zhang, Liangxiao; Li, Peiwu; Mao, Jin; Ma, Fei; Ding, Xiaoxia; Zhang, Qi

    2015-09-30

    Outlier detection is crucial in building a highly predictive model. In this study, we proposed an enhanced Monte Carlo outlier detection method by establishing cross-prediction models based on determinate normal samples and analyzing the distribution of prediction errors individually for dubious samples. One simulated and three real datasets were used to illustrate and validate the performance of our method, and the results indicated that this method outperformed Monte Carlo outlier detection in outlier diagnosis. After these outliers were removed, the value of validation by Kovats retention indices and the root mean square error of prediction decreased from 3.195 to 1.655, and the average cross-validation prediction error decreased from 2.0341 to 1.2780. This method helps establish a good model by eliminating outliers. © 2015 Wiley Periodicals, Inc.

  1. Status of Monte Carlo at Los Alamos

    SciTech Connect

    Thompson, W.L.; Cashwell, E.D.

    1980-01-01

    At Los Alamos the early work of Fermi, von Neumann, and Ulam has been developed and supplemented by many followers, notably Cashwell and Everett, and the main product today is the continuous-energy, general-purpose, generalized-geometry, time-dependent, coupled neutron-photon transport code called MCNP. The Los Alamos Monte Carlo research and development effort is concentrated in Group X-6. MCNP treats an arbitrary three-dimensional configuration of arbitrary materials in geometric cells bounded by first- and second-degree surfaces and some fourth-degree surfaces (elliptical tori). Monte Carlo has evolved into perhaps the main method for radiation transport calculations at Los Alamos. MCNP is used in every technical division at the Laboratory by over 130 users about 600 times a month accounting for nearly 200 hours of CDC-7600 time.

  2. Monte Carlo simulations on SIMD computer architectures

    SciTech Connect

    Burmester, C.P.; Gronsky, R.; Wille, L.T.

    1992-03-01

    Algorithmic considerations regarding the implementation of various materials science applications of the Monte Carlo technique to single instruction multiple data (SMM) computer architectures are presented. In particular, implementation of the Ising model with nearest, next nearest, and long range screened Coulomb interactions on the SIMD architecture MasPar MP-1 (DEC mpp-12000) series of massively parallel computers is demonstrated. Methods of code development which optimize processor array use and minimize inter-processor communication are presented including lattice partitioning and the use of processor array spanning tree structures for data reduction. Both geometric and algorithmic parallel approaches are utilized. Benchmarks in terms of Monte Carlo updates per second for the MasPar architecture are presented and compared to values reported in the literature from comparable studies on other architectures.

  3. Status of Monte Carlo at Los Alamos

    SciTech Connect

    Thompson, W.L.; Cashwell, E.D.; Godfrey, T.N.K.; Schrandt, R.G.; Deutsch, O.L.; Booth, T.E.

    1980-05-01

    Four papers were presented by Group X-6 on April 22, 1980, at the Oak Ridge Radiation Shielding Information Center (RSIC) Seminar-Workshop on Theory and Applications of Monte Carlo Methods. These papers are combined into one report for convenience and because they are related to each other. The first paper (by Thompson and Cashwell) is a general survey about X-6 and MCNP and is an introduction to the other three papers. It can also serve as a resume of X-6. The second paper (by Godfrey) explains some of the details of geometry specification in MCNP. The third paper (by Cashwell and Schrandt) illustrates calculating flux at a point with MCNP; in particular, the once-more-collided flux estimator is demonstrated. Finally, the fourth paper (by Thompson, Deutsch, and Booth) is a tutorial on some variance-reduction techniques. It should be required for a fledging Monte Carlo practitioner.

  4. Fission Matrix Capability for MCNP Monte Carlo

    NASA Astrophysics Data System (ADS)

    Brown, Forrest; Carney, Sean; Kiedrowski, Brian; Martin, William

    2014-06-01

    We describe recent experience and results from implementing a fission matrix capability into the MCNP Monte Carlo code. The fission matrix can be used to provide estimates of the fundamental mode fission distribution, the dominance ratio, the eigenvalue spectrum, and higher mode forward and adjoint eigenfunctions of the fission neutron source distribution. It can also be used to accelerate the convergence of the power method iterations and to provide basis functions for higher-order perturbation theory. The higher-mode fission sources can be used in MCNP to determine higher-mode forward fluxes and tallies, and work is underway to provide higher-mode adjoint-weighted fluxes and tallies. Past difficulties and limitations of the fission matrix approach are overcome with a new sparse representation of the matrix, permitting much larger and more accurate fission matrix representations. The new fission matrix capabilities provide a significant advance in the state-of-the-art for Monte Carlo criticality calculations.

  5. Quantum Monte Carlo applied to solids

    SciTech Connect

    Shulenburger, Luke; Mattsson, Thomas R.

    2013-12-01

    We apply diffusion quantum Monte Carlo to a broad set of solids, benchmarking the method by comparing bulk structural properties (equilibrium volume and bulk modulus) to experiment and density functional theory (DFT) based theories. The test set includes materials with many different types of binding including ionic, metallic, covalent, and van der Waals. We show that, on average, the accuracy is comparable to or better than that of DFT when using the new generation of functionals, including one hybrid functional and two dispersion corrected functionals. The excellent performance of quantum Monte Carlo on solids is promising for its application to heterogeneous systems and high-pressure/high-density conditions. Important to the results here is the application of a consistent procedure with regards to the several approximations that are made, such as finite-size corrections and pseudopotential approximations. This test set allows for any improvements in these methods to be judged in a systematic way.

  6. Venus - Detailed mapping of Maxwell Montes region

    NASA Astrophysics Data System (ADS)

    Alexandrov, Yu. N.; Crymov, A. A.; Kotelnikov, V. A.; Petrov, G. M.; Rzhiga, O. N.; Sidorenko, A. I.; Sinilo, V. P.; Zakharov, A. I.; Akim, E. L.; Basilevski, A. T.; Kadnichanski, S. A.; Tjuflin, Yu. S.

    1986-03-01

    From October 1983 to July 1984, the north hemisphere of Venus, from latitude 30° to latitude 90°, was mapped by means of the radar imagers and altimeters of the spacecraft Venera 15 and Venera 16. This report presents the results of the radar mapping of the Maxwell Montes region, one of the most interesting features of Venus' surface. A radar mosaic map and contour map have been compiled.

  7. Applications of Maxent to quantum Monte Carlo

    SciTech Connect

    Silver, R.N.; Sivia, D.S.; Gubernatis, J.E. ); Jarrell, M. . Dept. of Physics)

    1990-01-01

    We consider the application of maximum entropy methods to the analysis of data produced by computer simulations. The focus is the calculation of the dynamical properties of quantum many-body systems by Monte Carlo methods, which is termed the Analytical Continuation Problem.'' For the Anderson model of dilute magnetic impurities in metals, we obtain spectral functions and transport coefficients which obey Kondo Universality.'' 24 refs., 7 figs.

  8. Inhomogeneous Monte Carlo simulations of dermoscopic spectroscopy

    NASA Astrophysics Data System (ADS)

    Gareau, Daniel S.; Li, Ting; Jacques, Steven; Krueger, James

    2012-03-01

    Clinical skin-lesion diagnosis uses dermoscopy: 10X epiluminescence microscopy. Skin appearance ranges from black to white with shades of blue, red, gray and orange. Color is an important diagnostic criteria for diseases including melanoma. Melanin and blood content and distribution impact the diffuse spectral remittance (300-1000nm). Skin layers: immersion medium, stratum corneum, spinous epidermis, basal epidermis and dermis as well as laterally asymmetric features (eg. melanocytic invasion) were modeled in an inhomogeneous Monte Carlo model.

  9. Recovering intrinsic fluorescence by Monte Carlo modeling.

    PubMed

    Müller, Manfred; Hendriks, Benno H W

    2013-02-01

    We present a novel way to recover intrinsic fluorescence in turbid media based on Monte Carlo generated look-up tables and making use of a diffuse reflectance measurement taken at the same location. The method has been validated on various phantoms with known intrinsic fluorescence and is benchmarked against photon-migration methods. This new method combines more flexibility in the probe design with fast reconstruction and showed similar reconstruction accuracy as found in other reconstruction methods.

  10. Monte Carlo approach to Estrada index

    NASA Astrophysics Data System (ADS)

    Gutman, Ivan; Radenković, Slavko; Graovac, Ante; Plavšić, Dejan

    2007-09-01

    Let G be a graph on n vertices, and let λ1, λ2, …, λn be its eigenvalues. The Estrada index of G is a recently introduced molecular structure descriptor, defined as EE=∑i=1ne. Using a Monte Carlo approach, and treating the graph eigenvalues as random variables, we deduce approximate expressions for EE, in terms of the number of vertices and number of edges, of very high accuracy.

  11. Accelerated Monte Carlo by Embedded Cluster Dynamics

    NASA Astrophysics Data System (ADS)

    Brower, R. C.; Gross, N. A.; Moriarty, K. J. M.

    1991-07-01

    We present an overview of the new methods for embedding Ising spins in continuous fields to achieve accelerated cluster Monte Carlo algorithms. The methods of Brower and Tamayo and Wolff are summarized and variations are suggested for the O( N) models based on multiple embedded Z2 spin components and/or correlated projections. Topological features are discussed for the XY model and numerical simulations presented for d=2, d=3 and mean field theory lattices.

  12. 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.

  13. 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

  14. 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

  15. Neurocognitive Predictors of Mathematical Processing in School-Aged Children with Spina Bifida and Their Typically Developing Peers: Attention, Working Memory, and Fine Motor Skills

    PubMed Central

    Raghubar, Kimberly P.; Barnes, Marcia A.; Dennis, Maureen; Cirino, Paul T.; Taylor, Heather; Landry, Susan

    2015-01-01

    Objective Math and attention are related in neurobiological and behavioral models of mathematical cognition. This study employed model-driven assessments of attention and math in children with spina bifida myelomeningocele (SBM), who have known math difficulties and specific attentional deficits, to more directly examine putative relations between attention and mathematical processing. The relation of other domain general abilities and math was also investigated. Method Participants were 9.5-year-old children with SBM (N = 44) and typically developing children (N = 50). Participants were administered experimental exact and approximate arithmetic tasks, and standardized measures of math fluency and calculation. Cognitive measures included the Attention Network Test (ANT), and standardized measures of fine motor skills, verbal working memory (WM), and visual-spatial WM. Results Children with SBM performed similarly to peers on exact arithmetic but more poorly on approximate and standardized arithmetic measures. On the ANT, children with SBM differed from controls on orienting attention but not alerting and executive attention. Multiple mediation models showed that: fine motor skills and verbal WM mediated the relation of group to approximate arithmetic; fine motor skills and visual-spatial WM mediated the relation of group to math fluency; and verbal and visual-spatial WM mediated the relation of group to math calculation. Attention was not a significant mediator of the effects of group for any aspect of math in this study. Conclusions Results are discussed with reference to models of attention, WM, and mathematical cognition. PMID:26011113

  16. Path Integral Monte Carlo Methods for Fermions

    NASA Astrophysics Data System (ADS)

    Ethan, Ethan; Dubois, Jonathan; Ceperley, David

    2014-03-01

    In general, Quantum Monte Carlo methods suffer from a sign problem when simulating fermionic systems. This causes the efficiency of a simulation to decrease exponentially with the number of particles and inverse temperature. To circumvent this issue, a nodal constraint is often implemented, restricting the Monte Carlo procedure from sampling paths that cause the many-body density matrix to change sign. Unfortunately, this high-dimensional nodal surface is not a priori known unless the system is exactly solvable, resulting in uncontrolled errors. We will discuss two possible routes to extend the applicability of finite-temperatue path integral Monte Carlo. First we extend the regime where signful simulations are possible through a novel permutation sampling scheme. Afterwards, we discuss a method to variationally improve the nodal surface by minimizing a free energy during simulation. Applications of these methods will include both free and interacting electron gases, concluding with discussion concerning extension to inhomogeneous systems. Support from DOE DE-FG52-09NA29456, DE-AC52-07NA27344, LLNL LDRD 10- ERD-058, and the Lawrence Scholar program.

  17. Four decades of implicit Monte Carlo

    SciTech Connect

    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 forms 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.

  18. 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

  19. A palaeomagnetic study of Apennine thrusts, Italy: Monte Maiella and Monte Raparo

    NASA Astrophysics Data System (ADS)

    Jackson, K. C.

    1990-06-01

    Three separate structural blocks within the southern Apennines have been sampled for palaeomagnetic investigation to constrain their original separation and movement during mid-Tertiary deformation. The Mesozoic limestones are weakly magnetic, and the NRM intensity of all samples from Upper and Lower Cretaceous limestone from the Alburni platform and from Upper Cretaceous limestone at Monte Maiella were too low to yield results. Lower Cretaceous limestone at Monte Maiella contained a mean magnetisation (after structural correction) of D = 326°, I = +42°, k = 44, N = 9 (57°N, 263°E); and Cretaceous (?) limestone at Monte Raparo a mean of D = 132°, I = -61°, k = 50, N = 19 (54° N, 306°E). The Monte Maiella results, near the central part of the Apennine thrust-front, are compatible with a local, clockwise block-rotation during deformation, while Monte Raparo results may bear evidence of the major east-west thrust-motion during shortening in addition to anticlockwise block-rotations already reported from the southernmost Apennines.

  20. Monte Carlo simulation of intercalated carbon nanotubes.

    PubMed

    Mykhailenko, Oleksiy; Matsui, Denis; Prylutskyy, Yuriy; Le Normand, Francois; Eklund, Peter; Scharff, Peter

    2007-01-01

    Monte Carlo simulations of the single- and double-walled carbon nanotubes (CNT) intercalated with different metals have been carried out. The interrelation between the length of a CNT, the number and type of metal atoms has also been established. This research is aimed at studying intercalated systems based on CNTs and d-metals such as Fe and Co. Factors influencing the stability of these composites have been determined theoretically by the Monte Carlo method with the Tersoff potential. The modeling of CNTs intercalated with metals by the Monte Carlo method has proved that there is a correlation between the length of a CNT and the number of endo-atoms of specific type. Thus, in the case of a metallic CNT (9,0) with length 17 bands (3.60 nm), in contrast to Co atoms, Fe atoms are extruded out of the CNT if the number of atoms in the CNT is not less than eight. Thus, this paper shows that a CNT of a certain size can be intercalated with no more than eight Fe atoms. The systems investigated are stabilized by coordination of 3d-atoms close to the CNT wall with a radius-vector of (0.18-0.20) nm. Another characteristic feature is that, within the temperature range of (400-700) K, small systems exhibit ground-state stabilization which is not characteristic of the higher ones. The behavior of Fe and Co endo-atoms between the walls of a double-walled carbon nanotube (DW CNT) is explained by a dominating van der Waals interaction between the Co atoms themselves, which is not true for the Fe atoms.

  1. Venus - Maxwell Montes and Cleopatra Crater

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This Magellan full-resolution image shows Maxwell Montes, and is centered at 65 degrees north latitude and 6 degrees east longitude. Maxwell is the highest mountain on Venus, rising almost 11 kilometers (6.8 miles) above mean planetary radius. The western slopes (on the left) are very steep, whereas the eastern slopes descend gradually into Fortuna Tessera. The broad ridges and valleys making up Maxwell and Fortuna suggest that the topography resulted from compression. Most of Maxwell Montes has a very bright radar return; such bright returns are common on Venus at high altitudes. This phenomenon is thought to result from the presence of a radar reflective mineral such as pyrite. Interestingly, the highest area on Maxwell is less bright than the surrounding slopes, suggesting that the phenomenon is limited to a particular elevation range. The pressure, temperature, and chemistry of the atmosphere vary with altitude; the material responsible for the bright return probably is only stable in a particular range of atmospheric conditions and therefore a particular elevation range. The prominent circular feature in eastern Maxwell is Cleopatra. Cleopatra is a double-ring impact basin about 100 kilometers (62 miles) in diameter and 2.5 kilometers (1.5 miles) deep. A steep-walled, winding channel a few kilometers wide breaks through the rough terrain surrounding the crater rim. A large amount of lava originating in Cleopatra flowed through this channel and filled valleys in Fortuna Tessera. Cleopatra is superimposed on the structures of Maxwell Montes and appears to be undeformed, indicating that Cleopatra is relatively young.

  2. Quantum Monte Carlo for vibrating molecules

    SciTech Connect

    Brown, W.R. |

    1996-08-01

    Quantum Monte Carlo (QMC) has successfully computed the total electronic energies of atoms and molecules. The main goal of this work is to use correlation function quantum Monte Carlo (CFQMC) to compute the vibrational state energies of molecules given a potential energy surface (PES). In CFQMC, an ensemble of random walkers simulate the diffusion and branching processes of the imaginary-time time dependent Schroedinger equation in order to evaluate the matrix elements. The program QMCVIB was written to perform multi-state VMC and CFQMC calculations and employed for several calculations of the H{sub 2}O and C{sub 3} vibrational states, using 7 PES`s, 3 trial wavefunction forms, two methods of non-linear basis function parameter optimization, and on both serial and parallel computers. In order to construct accurate trial wavefunctions different wavefunctions forms were required for H{sub 2}O and C{sub 3}. In order to construct accurate trial wavefunctions for C{sub 3}, the non-linear parameters were optimized with respect to the sum of the energies of several low-lying vibrational states. In order to stabilize the statistical error estimates for C{sub 3} the Monte Carlo data was collected into blocks. Accurate vibrational state energies were computed using both serial and parallel QMCVIB programs. Comparison of vibrational state energies computed from the three C{sub 3} PES`s suggested that a non-linear equilibrium geometry PES is the most accurate and that discrete potential representations may be used to conveniently determine vibrational state energies.

  3. A Monte Carlo approach to water management

    NASA Astrophysics Data System (ADS)

    Koutsoyiannis, D.

    2012-04-01

    Common methods for making optimal decisions in water management problems are insufficient. Linear programming methods are inappropriate because hydrosystems are nonlinear with respect to their dynamics, operation constraints and objectives. Dynamic programming methods are inappropriate because water management problems cannot be divided into sequential stages. Also, these deterministic methods cannot properly deal with the uncertainty of future conditions (inflows, demands, etc.). Even stochastic extensions of these methods (e.g. linear-quadratic-Gaussian control) necessitate such drastic oversimplifications of hydrosystems that may make the obtained results irrelevant to the real world problems. However, a Monte Carlo approach is feasible and can form a general methodology applicable to any type of hydrosystem. This methodology uses stochastic simulation to generate system inputs, either unconditional or conditioned on a prediction, if available, and represents the operation of the entire system through a simulation model as faithful as possible, without demanding a specific mathematical form that would imply oversimplifications. Such representation fully respects the physical constraints, while at the same time it evaluates the system operation constraints and objectives in probabilistic terms, and derives their distribution functions and statistics through Monte Carlo simulation. As the performance criteria of a hydrosystem operation will generally be highly nonlinear and highly nonconvex functions of the control variables, a second Monte Carlo procedure, implementing stochastic optimization, is necessary to optimize system performance and evaluate the control variables of the system. The latter is facilitated if the entire representation is parsimonious, i.e. if the number of control variables is kept at a minimum by involving a suitable system parameterization. The approach is illustrated through three examples for (a) a hypothetical system of two reservoirs

  4. Status of Monte-Carlo Event Generators

    SciTech Connect

    Hoeche, Stefan; /SLAC

    2011-08-11

    Recent progress on general-purpose Monte-Carlo event generators is reviewed with emphasis on the simulation of hard QCD processes and subsequent parton cascades. Describing full final states of high-energy particle collisions in contemporary experiments is an intricate task. Hundreds of particles are typically produced, and the reactions involve both large and small momentum transfer. The high-dimensional phase space makes an exact solution of the problem impossible. Instead, one typically resorts to regarding events as factorized into different steps, ordered descending in the mass scales or invariant momentum transfers which are involved. In this picture, a hard interaction, described through fixed-order perturbation theory, is followed by multiple Bremsstrahlung emissions off initial- and final-state and, finally, by the hadronization process, which binds QCD partons into color-neutral hadrons. Each of these steps can be treated independently, which is the basic concept inherent to general-purpose event generators. Their development is nowadays often focused on an improved description of radiative corrections to hard processes through perturbative QCD. In this context, the concept of jets is introduced, which allows to relate sprays of hadronic particles in detectors to the partons in perturbation theory. In this talk, we briefly review recent progress on perturbative QCD in event generation. The main focus lies on the general-purpose Monte-Carlo programs HERWIG, PYTHIA and SHERPA, which will be the workhorses for LHC phenomenology. A detailed description of the physics models included in these generators can be found in [8]. We also discuss matrix-element generators, which provide the parton-level input for general-purpose Monte Carlo.

  5. Monte Carlo algorithm for free energy calculation.

    PubMed

    Bi, Sheng; Tong, Ning-Hua

    2015-07-01

    We propose a Monte Carlo algorithm for the free energy calculation based on configuration space sampling. An upward or downward temperature scan can be used to produce F(T). We implement this algorithm for the Ising model on a square lattice and triangular lattice. Comparison with the exact free energy shows an excellent agreement. We analyze the properties of this algorithm and compare it with the Wang-Landau algorithm, which samples in energy space. This method is applicable to general classical statistical models. The possibility of extending it to quantum systems is discussed.

  6. MBR Monte Carlo Simulation in PYTHIA8

    NASA Astrophysics Data System (ADS)

    Ciesielski, R.

    We present the MBR (Minimum Bias Rockefeller) Monte Carlo simulation of (anti)proton-proton interactions and its implementation in the PYTHIA8 event generator. We discuss the total, elastic, and total-inelastic cross sections, and three contributions from diffraction dissociation processes that contribute to the latter: single diffraction, double diffraction, and central diffraction or double-Pomeron exchange. The event generation follows a renormalized-Regge-theory model, successfully tested using CDF data. Based on the MBR-enhanced PYTHIA8 simulation, we present cross-section predictions for the LHC and beyond, up to collision energies of 50 TeV.

  7. Monte Carlo procedure for protein design

    NASA Astrophysics Data System (ADS)

    Irbäck, Anders; Peterson, Carsten; Potthast, Frank; Sandelin, Erik

    1998-11-01

    A method for sequence optimization in protein models is presented. The approach, which has inherited its basic philosophy from recent work by Deutsch and Kurosky [Phys. Rev. Lett. 76, 323 (1996)] by maximizing conditional probabilities rather than minimizing energy functions, is based upon a different and very efficient multisequence Monte Carlo scheme. By construction, the method ensures that the designed sequences represent good folders thermodynamically. A bootstrap procedure for the sequence space search is devised making very large chains feasible. The algorithm is successfully explored on the two-dimensional HP model [K. F. Lau and K. A. Dill, Macromolecules 32, 3986 (1989)] with chain lengths N=16, 18, and 32.

  8. Monte Carlo methods to calculate impact probabilities

    NASA Astrophysics Data System (ADS)

    Rickman, H.; Wiśniowski, T.; Wajer, P.; Gabryszewski, R.; Valsecchi, G. B.

    2014-09-01

    Context. Unraveling the events that took place in the solar system during the period known as the late heavy bombardment requires the interpretation of the cratered surfaces of the Moon and terrestrial planets. This, in turn, requires good estimates of the statistical impact probabilities for different source populations of projectiles, a subject that has received relatively little attention, since the works of Öpik (1951, Proc. R. Irish Acad. Sect. A, 54, 165) and Wetherill (1967, J. Geophys. Res., 72, 2429). Aims: We aim to work around the limitations of the Öpik and Wetherill formulae, which are caused by singularities due to zero denominators under special circumstances. Using modern computers, it is possible to make good estimates of impact probabilities by means of Monte Carlo simulations, and in this work, we explore the available options. Methods: We describe three basic methods to derive the average impact probability for a projectile with a given semi-major axis, eccentricity, and inclination with respect to a target planet on an elliptic orbit. One is a numerical averaging of the Wetherill formula; the next is a Monte Carlo super-sizing method using the target's Hill sphere. The third uses extensive minimum orbit intersection distance (MOID) calculations for a Monte Carlo sampling of potentially impacting orbits, along with calculations of the relevant interval for the timing of the encounter allowing collision. Numerical experiments are carried out for an intercomparison of the methods and to scrutinize their behavior near the singularities (zero relative inclination and equal perihelion distances). Results: We find an excellent agreement between all methods in the general case, while there appear large differences in the immediate vicinity of the singularities. With respect to the MOID method, which is the only one that does not involve simplifying assumptions and approximations, the Wetherill averaging impact probability departs by diverging toward

  9. Markov chain Monte Carlo without likelihoods.

    PubMed

    Marjoram, Paul; Molitor, John; Plagnol, Vincent; Tavare, Simon

    2003-12-23

    Many stochastic simulation approaches for generating observations from a posterior distribution depend on knowing a likelihood function. However, for many complex probability models, such likelihoods are either impossible or computationally prohibitive to obtain. Here we present a Markov chain Monte Carlo method for generating observations from a posterior distribution without the use of likelihoods. It can also be used in frequentist applications, in particular for maximum-likelihood estimation. The approach is illustrated by an example of ancestral inference in population genetics. A number of open problems are highlighted in the discussion.

  10. Discovering correlated fermions using quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Wagner, Lucas K.; Ceperley, David M.

    2016-09-01

    It has become increasingly feasible to use quantum Monte Carlo (QMC) methods to study correlated fermion systems for realistic Hamiltonians. We give a summary of these techniques targeted at researchers in the field of correlated electrons, focusing on the fundamentals, capabilities, and current status of this technique. The QMC methods often offer the highest accuracy solutions available for systems in the continuum, and, since they address the many-body problem directly, the simulations can be analyzed to obtain insight into the nature of correlated quantum behavior.

  11. Exascale Monte Carlo R&D

    SciTech Connect

    Marcus, Ryan C.

    2012-07-24

    Overview of this presentation is (1) Exascale computing - different technologies, getting there; (2) high-performance proof-of-concept MCMini - features and results; and (3) OpenCL toolkit - Oatmeal (OpenCL Automatic Memory Allocation Library) - purpose and features. Despite driver issues, OpenCL seems like a good, hardware agnostic tool. MCMini demonstrates the possibility for GPGPU-based Monte Carlo methods - it shows great scaling for HPC application and algorithmic equivalence. Oatmeal provides a flexible framework to aid in the development of scientific OpenCL codes.

  12. Quantum Monte Carlo calculations for light nuclei

    SciTech Connect

    Wiringa, R.B.

    1998-08-01

    Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 30 different (j{sup {prime}}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.

  13. Introduction to Cluster Monte Carlo Algorithms

    NASA Astrophysics Data System (ADS)

    Luijten, E.

    This chapter provides an introduction to cluster Monte Carlo algorithms for classical statistical-mechanical systems. A brief review of the conventional Metropolis algorithm is given, followed by a detailed discussion of the lattice cluster algorithm developed by Swendsen and Wang and the single-cluster variant introduced by Wolff. For continuum systems, the geometric cluster algorithm of Dress and Krauth is described. It is shown how their geometric approach can be generalized to incorporate particle interactions beyond hardcore repulsions, thus forging a connection between the lattice and continuum approaches. Several illustrative examples are discussed.

  14. Cluster hybrid Monte Carlo simulation algorithms.

    PubMed

    Plascak, J A; Ferrenberg, Alan M; Landau, D P

    2002-06-01

    We show that addition of Metropolis single spin flips to the Wolff cluster-flipping Monte Carlo procedure leads to a dramatic increase in performance for the spin-1/2 Ising model. We also show that adding Wolff cluster flipping to the Metropolis or heat bath algorithms in systems where just cluster flipping is not immediately obvious (such as the spin-3/2 Ising model) can substantially reduce the statistical errors of the simulations. A further advantage of these methods is that systematic errors introduced by the use of imperfect random-number generation may be largely healed by hybridizing single spin flips with cluster flipping.

  15. Cluster hybrid Monte Carlo simulation algorithms

    NASA Astrophysics Data System (ADS)

    Plascak, J. A.; Ferrenberg, Alan M.; Landau, D. P.

    2002-06-01

    We show that addition of Metropolis single spin flips to the Wolff cluster-flipping Monte Carlo procedure leads to a dramatic increase in performance for the spin-1/2 Ising model. We also show that adding Wolff cluster flipping to the Metropolis or heat bath algorithms in systems where just cluster flipping is not immediately obvious (such as the spin-3/2 Ising model) can substantially reduce the statistical errors of the simulations. A further advantage of these methods is that systematic errors introduced by the use of imperfect random-number generation may be largely healed by hybridizing single spin flips with cluster flipping.

  16. Monte Carlo simulation for the transport beamline

    NASA Astrophysics Data System (ADS)

    Romano, F.; Attili, A.; Cirrone, G. A. P.; Carpinelli, M.; Cuttone, G.; Jia, S. B.; Marchetto, F.; Russo, G.; Schillaci, F.; Scuderi, V.; Tramontana, A.; Varisano, A.

    2013-07-01

    In the framework of the ELIMED project, Monte Carlo (MC) simulations are widely used to study the physical transport of charged particles generated by laser-target interactions and to preliminarily evaluate fluence and dose distributions. An energy selection system and the experimental setup for the TARANIS laser facility in Belfast (UK) have been already simulated with the GEANT4 (GEometry ANd Tracking) MC toolkit. Preliminary results are reported here. Future developments are planned to implement a MC based 3D treatment planning in order to optimize shots number and dose delivery.

  17. State-of-the-art Monte Carlo 1988

    SciTech Connect

    Soran, P.D.

    1988-06-28

    Particle transport calculations in highly dimensional and physically complex geometries, such as detector calibration, radiation shielding, space reactors, and oil-well logging, generally require Monte Carlo transport techniques. Monte Carlo particle transport can be performed on a variety of computers ranging from APOLLOs to VAXs. Some of the hardware and software developments, which now permit Monte Carlo methods to be routinely used, are reviewed in this paper. The development of inexpensive, large, fast computer memory, coupled with fast central processing units, permits Monte Carlo calculations to be performed on workstations, minicomputers, and supercomputers. The Monte Carlo renaissance is further aided by innovations in computer architecture and software development. Advances in vectorization and parallelization architecture have resulted in the development of new algorithms which have greatly reduced processing times. Finally, the renewed interest in Monte Carlo has spawned new variance reduction techniques which are being implemented in large computer codes. 45 refs.

  18. Discrete diffusion Monte Carlo for frequency-dependent radiative transfer

    SciTech Connect

    Densmore, Jeffrey D; Kelly, Thompson G; Urbatish, Todd J

    2010-11-17

    Discrete Diffusion Monte Carlo (DDMC) is a technique for increasing the efficiency of Implicit Monte Carlo radiative-transfer simulations. In this paper, we develop an extension of DDMC for frequency-dependent radiative transfer. We base our new DDMC method on a frequency-integrated diffusion equation for frequencies below a specified threshold. Above this threshold we employ standard Monte Carlo. With a frequency-dependent test problem, we confirm the increased efficiency of our new DDMC technique.

  19. 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

  20. 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.

  1. Calculating Pi Using the Monte Carlo Method

    NASA Astrophysics Data System (ADS)

    Williamson, Timothy

    2013-11-01

    During the summer of 2012, I had the opportunity to participate in a research experience for teachers at the center for sustainable energy at Notre Dame University (RET @ cSEND) working with Professor John LoSecco on the problem of using antineutrino detection to accurately determine the fuel makeup and operating power of nuclear reactors. During full power operation, a reactor may produce 1021 antineutrinos per second with approximately 100 per day being detected. While becoming familiar with the design and operation of the detectors, and how total antineutrino flux could be obtained from such a small sample, I read about a simulation program called Monte Carlo. Further investigation led me to the Monte Carlo method page of Wikipedia2 where I saw an example of approximating pi using this simulation. Other examples where this method was applied were typically done with computer simulations2 or purely mathematical.3 It is my belief that this method may be easily related to the students by performing the simple activity of sprinkling rice on an arc drawn in a square. The activity that follows was inspired by those simulations and was used by my AP Physics class last year with very good results.

  2. Multilevel Monte Carlo simulation of Coulomb collisions

    SciTech Connect

    Rosin, M.S.; Ricketson, L.F.; Dimits, A.M.; Caflisch, R.E.; Cohen, B.I.

    2014-10-01

    We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε, the computational cost of the method is O(ε{sup −2}) or O(ε{sup −2}(lnε){sup 2}), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε{sup −3}) for direct simulation Monte Carlo or binary collision methods. We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10{sup −5}. We discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.

  3. Quantum Monte Carlo methods for nuclear physics

    SciTech Connect

    Carlson, Joseph A.; Gandolfi, Stefano; Pederiva, Francesco; Pieper, Steven C.; Schiavilla, Rocco; Schmidt, K. E,; Wiringa, Robert B.

    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-body 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.

  4. 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

  5. Geometrical Monte Carlo simulation of atmospheric turbulence

    NASA Astrophysics Data System (ADS)

    Yuksel, Demet; Yuksel, Heba

    2013-09-01

    Atmospheric turbulence has a significant impact on the quality of a laser beam propagating through the atmosphere over long distances. Turbulence causes intensity scintillation and beam wander from propagation through turbulent eddies of varying sizes and refractive index. This can severely impair the operation of target designation and Free-Space Optical (FSO) communications systems. In addition, experimenting on an FSO communication system is rather tedious and difficult. The interferences of plentiful elements affect the result and cause the experimental outcomes to have bigger error variance margins than they are supposed to have. Especially when we go into the stronger turbulence regimes the simulation and analysis of the turbulence induced beams require delicate attention. We propose a new geometrical model to assess the phase shift of a laser beam propagating through turbulence. The atmosphere along the laser beam propagation path will be modeled as a spatial distribution of spherical bubbles with refractive index discontinuity calculated from a Gaussian distribution with the mean value being the index of air. For each statistical representation of the atmosphere, the path of rays will be analyzed using geometrical optics. These Monte Carlo techniques will assess the phase shift as a summation of the phases that arrive at the same point at the receiver. Accordingly, there would be dark and bright spots at the receiver that give an idea regarding the intensity pattern without having to solve the wave equation. The Monte Carlo analysis will be compared with the predictions of wave theory.

  6. Scalable Domain Decomposed Monte Carlo Particle Transport

    NASA Astrophysics Data System (ADS)

    O'Brien, Matthew Joseph

    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. The main algorithms we consider are: • Domain decomposition of constructive solid geometry: enables extremely large calculations in which the background geometry is too large to fit in the memory of a single computational node. • Load Balancing: keeps the workload per processor as even as possible so the calculation runs efficiently. • Global Particle Find: if particles are on the wrong processor, globally resolve their locations to the correct processor based on particle coordinate and background domain. • Visualizing constructive solid geometry, sourcing particles, deciding that particle streaming communication is completed and spatial redecomposition. These algorithms are some of the most important parallel algorithms required for domain decomposed Monte Carlo particle transport. We demonstrate that our previous algorithms were not scalable, prove that our new algorithms are scalable, and run some of the algorithms up to 2 million MPI processes on the Sequoia supercomputer.

  7. Discrete range clustering using Monte Carlo methods

    NASA Technical Reports Server (NTRS)

    Chatterji, G. B.; Sridhar, B.

    1993-01-01

    For automatic obstacle avoidance guidance during rotorcraft low altitude flight, a reliable model of the nearby environment is needed. Such a model may be constructed by applying surface fitting techniques to the dense range map obtained by active sensing using radars. However, for covertness, passive sensing techniques using electro-optic sensors are desirable. As opposed to the dense range map obtained via active sensing, passive sensing algorithms produce reliable range at sparse locations, and therefore, surface fitting techniques to fill the gaps in the range measurement are not directly applicable. Both for automatic guidance and as a display for aiding the pilot, these discrete ranges need to be grouped into sets which correspond to objects in the nearby environment. The focus of this paper is on using Monte Carlo methods for clustering range points into meaningful groups. One of the aims of the paper is to explore whether simulated annealing methods offer significant advantage over the basic Monte Carlo method for this class of problems. We compare three different approaches and present application results of these algorithms to a laboratory image sequence and a helicopter flight sequence.

  8. Quantum Monte Carlo methods for nuclear physics

    DOE PAGES

    Carlson, J.; Gandolfi, S.; Pederiva, F.; ...

    2015-09-09

    Quantum Monte Carlo methods have proved 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. The nuclear interactions and currents are reviewed along with a description of 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,more » and three-body interactions. A variety of results are presented, including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. 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 are also described. Furthermore, a coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.« less

  9. CosmoMC: Cosmological MonteCarlo

    NASA Astrophysics Data System (ADS)

    Lewis, Antony; Bridle, Sarah

    2011-06-01

    We present a fast Markov Chain Monte-Carlo exploration of cosmological parameter space. We perform a joint analysis of results from recent CMB experiments and provide parameter constraints, including sigma_8, from the CMB independent of other data. We next combine data from the CMB, HST Key Project, 2dF galaxy redshift survey, supernovae Ia and big-bang nucleosynthesis. The Monte Carlo method allows the rapid investigation of a large number of parameters, and we present results from 6 and 9 parameter analyses of flat models, and an 11 parameter analysis of non-flat models. Our results include constraints on the neutrino mass (m_nu < 0.3eV), equation of state of the dark energy, and the tensor amplitude, as well as demonstrating the effect of additional parameters on the base parameter constraints. In a series of appendices we describe the many uses of importance sampling, including computing results from new data and accuracy correction of results generated from an approximate method. We also discuss the different ways of converting parameter samples to parameter constraints, the effect of the prior, assess the goodness of fit and consistency, and describe the use of analytic marginalization over normalization parameters.

  10. Quantum Monte Carlo methods for nuclear physics

    SciTech Connect

    Carlson, J.; Gandolfi, S.; Pederiva, F.; Pieper, Steven C.; Schiavilla, R.; Schmidt, K. E.; Wiringa, R. B.

    2015-09-09

    Quantum Monte Carlo methods have proved 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. The nuclear interactions and currents are reviewed along with a description of 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-body interactions. A variety of results are presented, including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. 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 are also described. Furthermore, a coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.

  11. Quantum Monte Carlo methods for nuclear physics

    NASA Astrophysics Data System (ADS)

    Carlson, J.; Gandolfi, S.; Pederiva, F.; Pieper, Steven C.; Schiavilla, R.; Schmidt, K. E.; Wiringa, R. B.

    2015-07-01

    Quantum Monte Carlo methods have proved 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. The nuclear interactions and currents are reviewed along with a description of 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-body interactions. A variety of results are presented, including the low-lying spectra of light nuclei, nuclear form factors, and transition matrix elements. 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 are also described. A coherent picture of nuclear structure and dynamics emerges based upon rather simple but realistic interactions and currents.

  12. Quantum Monte Carlo for atoms and molecules

    SciTech Connect

    Barnett, R.N.

    1989-11-01

    The diffusion quantum Monte Carlo with fixed nodes (QMC) approach has been employed in studying energy-eigenstates for 1--4 electron systems. Previous work employing the diffusion QMC technique yielded energies of high quality for H{sub 2}, LiH, Li{sub 2}, and H{sub 2}O. Here, the range of calculations with this new approach has been extended to include additional first-row atoms and molecules. In addition, improvements in the previously computed fixed-node energies of LiH, Li{sub 2}, and H{sub 2}O have been obtained using more accurate trial functions. All computations were performed within, but are not limited to, the Born-Oppenheimer approximation. In our computations, the effects of variation of Monte Carlo parameters on the QMC solution of the Schroedinger equation were studied extensively. These parameters include the time step, renormalization time and nodal structure. These studies have been very useful in determining which choices of such parameters will yield accurate QMC energies most efficiently. Generally, very accurate energies (90--100% of the correlation energy is obtained) have been computed with single-determinant trail functions multiplied by simple correlation functions. Improvements in accuracy should be readily obtained using more complex trial functions.

  13. THE MCNPX MONTE CARLO RADIATION TRANSPORT CODE

    SciTech Connect

    WATERS, LAURIE S.; MCKINNEY, GREGG W.; DURKEE, JOE W.; FENSIN, MICHAEL L.; JAMES, MICHAEL R.; JOHNS, RUSSELL C.; PELOWITZ, DENISE B.

    2007-01-10

    MCNPX (Monte Carlo N-Particle eXtended) is a general-purpose Monte Carlo radiation transport code with three-dimensional geometry and continuous-energy transport of 34 particles and light ions. It contains flexible source and tally options, interactive graphics, and support for both sequential and multi-processing computer platforms. MCNPX is based on MCNP4B, and has been upgraded to most MCNP5 capabilities. MCNP is a highly stable code tracking neutrons, photons and electrons, and using evaluated nuclear data libraries for low-energy interaction probabilities. MCNPX has extended this base to a comprehensive set of particles and light ions, with heavy ion transport in development. Models have been included to calculate interaction probabilities when libraries are not available. Recent additions focus on the time evolution of residual nuclei decay, allowing calculation of transmutation and delayed particle emission. MCNPX is now a code of great dynamic range, and the excellent neutronics capabilities allow new opportunities to simulate devices of interest to experimental particle physics; particularly calorimetry. This paper describes the capabilities of the current MCNPX version 2.6.C, and also discusses ongoing code development.

  14. Chemical application of diffusion quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Reynolds, P. J.; Lester, W. A., Jr.

    1983-10-01

    The diffusion quantum Monte Carlo (QMC) method gives a stochastic solution to the Schroedinger equation. As an example the singlet-triplet splitting of the energy of the methylene molecule CH2 is given. The QMC algorithm was implemented on the CYBER 205, first as a direct transcription of the algorithm running on our VAX 11/780, and second by explicitly writing vector code for all loops longer than a crossover length C. The speed of the codes relative to one another as a function of C, and relative to the VAX is discussed. Since CH2 has only eight electrons, most of the loops in this application are fairly short. The longest inner loops run over the set of atomic basis functions. The CPU time dependence obtained versus the number of basis functions is discussed and compared with that obtained from traditional quantum chemistry codes and that obtained from traditional computer architectures. Finally, preliminary work on restructuring the algorithm to compute the separate Monte Carlo realizations in parallel is discussed.

  15. Multilevel Monte Carlo simulation of Coulomb collisions

    DOE PAGES

    Rosin, M. S.; Ricketson, L. F.; Dimits, A. M.; ...

    2014-05-29

    We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε , the computational cost of the method is O(ε–2) or (ε–2(lnε)2), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε–3) for direct simulation Monte Carlo or binary collision methods.more » We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10–5. Lastly, we discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.« less

  16. Multilevel Monte Carlo simulation of Coulomb collisions

    SciTech Connect

    Rosin, M. S.; Ricketson, L. F.; Dimits, A. M.; Caflisch, R. E.; Cohen, B. I.

    2014-05-29

    We present a new, for plasma physics, highly efficient multilevel Monte Carlo numerical method for simulating Coulomb collisions. The method separates and optimally minimizes the finite-timestep and finite-sampling errors inherent in the Langevin representation of the Landau–Fokker–Planck equation. It does so by combining multiple solutions to the underlying equations with varying numbers of timesteps. For a desired level of accuracy ε , the computational cost of the method is O(ε–2) or (ε–2(lnε)2), depending on the underlying discretization, Milstein or Euler–Maruyama respectively. This is to be contrasted with a cost of O(ε–3) for direct simulation Monte Carlo or binary collision methods. We successfully demonstrate the method with a classic beam diffusion test case in 2D, making use of the Lévy area approximation for the correlated Milstein cross terms, and generating a computational saving of a factor of 100 for ε=10–5. Lastly, we discuss the importance of the method for problems in which collisions constitute the computational rate limiting step, and its limitations.

  17. Quantum Monte Carlo Endstation for Petascale Computing

    SciTech Connect

    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 Carlo 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 13

  18. Time spans of soil formation and late Pleistocene-Holocene climate changes in the Somma-Vesuvius volcano area, southern Italy

    NASA Astrophysics Data System (ADS)

    Scarciglia, Fabio; Zumpano, Veronica; Sulpizio, Roberto; Terribile, Fabio; Pulice, Iolanda; La Russa, Mauro F.

    2013-04-01

    Time spans of soil formation and climate changes occurred during the late Pleistocene to the middle Holocene are investigated in a pedostratigraphic succession located in the piedmont of the Somma-Vesuvius volcano (Campania region, southern Italy) using a multidisciplinary approach. We focused on five well-known and well-dated primary tephra and four interlayered volcanic soils developed on and/or buried by them. The pyroclastic layers give detailed chronological constraints to the stratigraphy. From bottom to top the following tephra were identified in the field: Pomici di Base (22 ka BP), Pomici Verdoline (19 ka BP), Agnano Pomici Principali (12.26 ka BP), Mercato (8.9 ka BP) and Avellino (3.9 ka BP), all of them representing volcanic products of explosive eruptions of the Somma-Vesuvius, except the third one, sourced from the westerly Phlegrean Fields. The four pedons were characterized in terms of morphological, physical, chemical, mineralogical and micromorphological features. Special attention was given to reconstruct the main soil-forming processes, paleoenvironmental and paleoclimatic conditions, degree of soil development and associated time ranges. Moreover, further tephra were identified in the field within some of above pedons. One of them was easily recognized and referred to the Agnano Monte Spina eruption (4.2-4.3 ka BP, Phlegrean Fields provenance), whereas the others were not previously known in the Somma-Vesuvius stratigraphy. On the basis of SEM-EDS analyses (chemical composition and morphoscopic observations), coupled with their stratigraphic position and literature compositional databases, they were related to the Soccavo 4-5 and the Tufi Biancastri eruptions from the Phlegrean Fields. This interpretation permitted to fix further age constrains for more detailed assessment of rates of soil formation and climatic interpretation. Major late Quaternary climatic phases are suggested by changes in the extent of development of andic properties, iron

  19. 78 FR 14031 - Proposed Amendment of Class D Airspace; El Monte, CA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-04

    ... Proposed Amendment of Class D Airspace; El Monte, CA AGENCY: Federal Aviation Administration (FAA), DOT... El Monte Airport, El Monte, CA. This action, initiated by the biennial review of the El Monte... El Monte Airport. DATES: Comments must be received on or before April 18, 2013. ADDRESSES:...

  20. Monte Carlo-Minimization and Monte Carlo Recursion Approaches to Structure and Free Energy.

    NASA Astrophysics Data System (ADS)

    Li, Zhenqin

    1990-08-01

    Biological systems are intrinsically "complex", involving many degrees of freedom, heterogeneity, and strong interactions among components. For the simplest of biological substances, e.g., biomolecules, which obey the laws of thermodynamics, we may attempt a statistical mechanical investigational approach. Even for these simplest many -body systems, assuming microscopic interactions are completely known, current computational methods in characterizing the overall structure and free energy face the fundamental challenge of an exponential amount of computation, with the rise in the number of degrees of freedom. As an attempt to surmount such problems, two computational procedures, the Monte Carlo-minimization and Monte Carlo recursion methods, have been developed as general approaches to the determination of structure and free energy of a complex thermodynamic system. We describe, in Chapter 2, the Monte Carlo-minimization method, which attempts to simulate natural protein folding processes and to overcome the multiple-minima problem. The Monte Carlo-minimization procedure has been applied to a pentapeptide, Met-enkephalin, leading consistently to the lowest energy structure, which is most likely to be the global minimum structure for Met-enkephalin in the absence of water, given the ECEPP energy parameters. In Chapter 3 of this thesis, we develop a Monte Carlo recursion method to compute the free energy of a given physical system with known interactions, which has been applied to a 32-particle Lennard-Jones fluid. In Chapter 4, we describe an efficient implementation of the recursion procedure, for the computation of the free energy of liquid water, with both MCY and TIP4P potential parameters for water. As a further demonstration of the power of the recursion method for calculating free energy, a general formalism of cluster formation from monatomic vapor is developed in Chapter 5. The Gibbs free energy of constrained clusters can be computed efficiently using the

  1. 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…

  2. Economic Risk Analysis: Using Analytical and Monte Carlo Techniques.

    ERIC Educational Resources Information Center

    O'Donnell, Brendan R.; Hickner, Michael A.; Barna, Bruce A.

    2002-01-01

    Describes the development and instructional use of a Microsoft Excel spreadsheet template that facilitates analytical and Monte Carlo risk analysis of investment decisions. Discusses a variety of risk assessment methods followed by applications of the analytical and Monte Carlo methods. Uses a case study to illustrate use of the spreadsheet tool…

  3. 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…

  4. Monte Carlo Simulation of Endlinking Oligomers

    NASA Technical Reports Server (NTRS)

    Hinkley, Jeffrey A.; Young, Jennifer A.

    1998-01-01

    This report describes initial efforts to model the endlinking reaction of phenylethynyl-terminated oligomers. Several different molecular weights were simulated using the Bond Fluctuation Monte Carlo technique on a 20 x 20 x 20 unit lattice with periodic boundary conditions. After a monodisperse "melt" was equilibrated, chain ends were linked whenever they came within the allowed bond distance. Ends remained reactive throughout, so that multiple links were permitted. Even under these very liberal crosslinking assumptions, geometrical factors limited the degree of crosslinking. Average crosslink functionalities were 2.3 to 2.6; surprisingly, they did not depend strongly on the chain length. These results agreed well with the degrees of crosslinking inferred from experiment in a cured phenylethynyl-terminated polyimide oligomer.

  5. Exploring theory space with Monte Carlo reweighting

    DOE PAGES

    Gainer, James S.; Lykken, Joseph; Matchev, Konstantin T.; ...

    2014-10-13

    Theories of new physics often involve a large number of unknown parameters which need to be scanned. Additionally, a putative signal in a particular channel may be due to a variety of distinct models of new physics. This makes experimental attempts to constrain the parameter space of motivated new physics models with a high degree of generality quite challenging. We describe how the reweighting of events may allow this challenge to be met, as fully simulated Monte Carlo samples generated for arbitrary benchmark models can be effectively re-used. Specifically, we suggest procedures that allow more efficient collaboration between theorists andmore » experimentalists in exploring large theory parameter spaces in a rigorous way at the LHC.« less

  6. Chemical application of diffusion quantum Monte Carlo

    NASA Technical Reports Server (NTRS)

    Reynolds, P. J.; Lester, W. A., Jr.

    1984-01-01

    The diffusion quantum Monte Carlo (QMC) method gives a stochastic solution to the Schroedinger equation. This approach is receiving increasing attention in chemical applications as a result of its high accuracy. However, reducing statistical uncertainty remains a priority because chemical effects are often obtained as small differences of large numbers. As an example, the single-triplet splitting of the energy of the methylene molecule CH sub 2 is given. The QMC algorithm was implemented on the CYBER 205, first as a direct transcription of the algorithm running on the VAX 11/780, and second by explicitly writing vector code for all loops longer than a crossover length C. The speed of the codes relative to one another as a function of C, and relative to the VAX, are discussed. The computational time dependence obtained versus the number of basis functions is discussed and this is compared with that obtained from traditional quantum chemistry codes and that obtained from traditional computer architectures.

  7. Monte Carlo calculation for microplanar beam radiography.

    PubMed

    Company, F Z; Allen, B J; Mino, C

    2000-09-01

    In radiography the scattered radiation from the off-target region decreases the contrast of the target image. We propose that a bundle of collimated, closely spaced, microplanar beams can reduce the scattered radiation and eliminate the effect of secondary electron dose, thus increasing the image dose contrast in the detector. The lateral and depth dose distributions of 20-200 keV microplanar beams are investigated using the EGS4 Monte Carlo code to calculate the depth doses and dose profiles in a 6 cm x 6 cm x 6 cm tissue phantom. The maximum dose on the primary beam axis (peak) and the minimum inter-beam scattered dose (valley) are compared at different photon energies and the optimum energy range for microbeam radiography is found. Results show that a bundle of closely spaced microplanar beams can give superior contrast imaging to a single macrobeam of the same overall area.

  8. Lunar Regolith Albedos Using Monte Carlos

    NASA Technical Reports Server (NTRS)

    Wilson, T. L.; Andersen, V.; Pinsky, L. S.

    2003-01-01

    The analysis of planetary regoliths for their backscatter albedos produced by cosmic rays (CRs) is important for space exploration and its potential contributions to science investigations in fundamental physics and astrophysics. Albedos affect all such experiments and the personnel that operate them. Groups have analyzed the production rates of various particles and elemental species by planetary surfaces when bombarded with Galactic CR fluxes, both theoretically and by means of various transport codes, some of which have emphasized neutrons. Here we report on the preliminary results of our current Monte Carlo investigation into the production of charged particles, neutrons, and neutrinos by the lunar surface using FLUKA. In contrast to previous work, the effects of charm are now included.

  9. Accuracy control in Monte Carlo radiative calculations

    NASA Technical Reports Server (NTRS)

    Almazan, P. Planas

    1993-01-01

    The general accuracy law that rules the Monte Carlo, ray-tracing algorithms used commonly for the calculation of the radiative entities in the thermal analysis of spacecraft are presented. These entities involve transfer of radiative energy either from a single source to a target (e.g., the configuration factors). or from several sources to a target (e.g., the absorbed heat fluxes). In fact, the former is just a particular case of the latter. The accuracy model is later applied to the calculation of some specific radiative entities. Furthermore, some issues related to the implementation of such a model in a software tool are discussed. Although only the relative error is considered through the discussion, similar results can be derived for the absolute error.

  10. Noncovalent Interactions by Quantum Monte Carlo.

    PubMed

    Dubecký, Matúš; Mitas, Lubos; Jurečka, Petr

    2016-05-11

    Quantum Monte Carlo (QMC) is a family of stochastic methods for solving quantum many-body problems such as the stationary Schrödinger equation. The review introduces basic notions of electronic structure QMC based on random walks in real space as well as its advances and adaptations to systems with noncovalent interactions. Specific issues such as fixed-node error cancellation, construction of trial wave functions, and efficiency considerations that allow for benchmark quality QMC energy differences are described in detail. Comprehensive overview of articles covers QMC applications to systems with noncovalent interactions over the last three decades. The current status of QMC with regard to efficiency, applicability, and usability by nonexperts together with further considerations about QMC developments, limitations, and unsolved challenges are discussed as well.

  11. Hybrid algorithms in quantum Monte Carlo

    NASA Astrophysics Data System (ADS)

    Kim, Jeongnim; Esler, Kenneth P.; McMinis, Jeremy; Morales, Miguel A.; Clark, Bryan K.; Shulenburger, Luke; Ceperley, David M.

    2012-12-01

    With advances in algorithms and growing computing powers, quantum Monte Carlo (QMC) methods have become a leading contender for high accuracy calculations for the electronic structure of realistic systems. The performance gain on recent HPC systems is largely driven by increasing parallelism: the number of compute cores of a SMP and the number of SMPs have been going up, as the Top500 list attests. However, the available memory as well as the communication and memory bandwidth per element has not kept pace with the increasing parallelism. This severely limits the applicability of QMC and the problem size it can handle. OpenMP/MPI hybrid programming provides applications with simple but effective solutions to overcome efficiency and scalability bottlenecks on large-scale clusters based on multi/many-core SMPs. We discuss the design and implementation of hybrid methods in QMCPACK and analyze its performance on current HPC platforms characterized by various memory and communication hierarchies.

  12. Monte Carlo applications to acoustical field solutions

    NASA Technical Reports Server (NTRS)

    Haviland, J. K.; Thanedar, B. D.

    1973-01-01

    The Monte Carlo technique is proposed for the determination of the acoustical pressure-time history at chosen points in a partial enclosure, the central idea of this technique being the tracing of acoustical rays. A statistical model is formulated and an algorithm for pressure is developed, the conformity of which is examined by two approaches and is shown to give the known results. The concepts that are developed are applied to the determination of the transient field due to a sound source in a homogeneous medium in a rectangular enclosure with perfect reflecting walls, and the results are compared with those presented by Mintzer based on the Laplace transform approach, as well as with a normal mode solution.

  13. Monte Carlo modeling and meteor showers

    NASA Technical Reports Server (NTRS)

    Kulikova, N. V.

    1987-01-01

    Prediction of short lived increases in the cosmic dust influx, the concentration in lower thermosphere of atoms and ions of meteor origin and the determination of the frequency of micrometeor impacts on spacecraft are all of scientific and practical interest and all require adequate models of meteor showers at an early stage of their existence. A Monte Carlo model of meteor matter ejection from a parent body at any point of space was worked out by other researchers. This scheme is described. According to the scheme, the formation of ten well known meteor streams was simulated and the possibility of genetic affinity of each of them with the most probable parent comet was analyzed. Some of the results are presented.

  14. The Chasmata and Montes of Charon

    NASA Astrophysics Data System (ADS)

    Beyer, R. A.; Schenk, P.; Spencer, J. R.; Moore, J. M.; Nimmo, F.; Barnouin, O. S.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.; Young, L. A.; McKinnon, W. B.

    2015-12-01

    The New Horizons spacecraft made the first-ever high-resolution observations of Pluto's largest moon, Charon, on 14 July 2015. Those observations returned views of complicated topography on this icy world in the outer solar system. Charon posseses a series of chasmata and fossae that appear to form an organized tectonic belt that spans across the disk of the Pluto-facing hemisphere and may extend beyond. In addition, there are enigmatic, isolated mountains visible that are surrounded by depressions. These, in turn, are surrounded by a relatively smooth plain, broken by occaisional rilles, that stretches from these montes northward up to the chasmata region. We will discuss these features and more.

  15. The Chasmata and Montes of Charon

    NASA Astrophysics Data System (ADS)

    Beyer, Ross A.; Barnouin, Olivier; Ennico, Kimberly; Moore, Jeff; Nimmo, Francis; Olkin, Cathy B.; Schenk, Paul; Spencer, John; Stern, S. Alan; Weaver, Hal A.; Young, Leslie A.

    2015-11-01

    The New Horizons spacecraft made the first-ever high-resolution observations of Pluto's largest moon, Charon, on 14 July 2015. Those observations returned views of complicated topography on this icy world in the outer solar system. Charon posseses a series of chasmata and fossae that appear to form an organized tectonic belt that spans across the disk of the Pluto-facing hemisphere and may extend beyond. In addition, there are enigmatic, isolated mountains visible that are surrounded by depressions. These, in turn, are surrounded by a relatively smooth plain, broken by occaisional rilles, that stretches from these montes northward up to the chasmata region. We will discuss these features and more. This work was supported by NASA's New Horizons project.

  16. Green's function Monte Carlo in nuclear physics

    SciTech Connect

    Carlson, J.

    1990-01-01

    We review the status of Green's Function Monte Carlo (GFMC) methods as applied to problems in nuclear physics. New methods have been developed to handle the spin and isospin degrees of freedom that are a vital part of any realistic nuclear physics problem, whether at the level of quarks or nucleons. We discuss these methods and then summarize results obtained recently for light nuclei, including ground state energies, three-body forces, charge form factors and the coulomb sum. As an illustration of the applicability of GFMC to quark models, we also consider the possible existence of bound exotic multi-quark states within the framework of flux-tube quark models. 44 refs., 8 figs., 1 tab.

  17. Resist develop prediction by Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Sohn, Dong-Soo; Jeon, Kyoung-Ah; Sohn, Young-Soo; Oh, Hye-Keun

    2002-07-01

    Various resist develop models have been suggested to express the phenomena from the pioneering work of Dill's model in 1975 to the recent Shipley's enhanced notch model. The statistical Monte Carlo method can be applied to the process such as development and post exposure bake. The motions of developer during development process were traced by using this method. We have considered that the surface edge roughness of the resist depends on the weight percentage of protected and de-protected polymer in the resist. The results are well agreed with other papers. This study can be helpful for the developing of new photoresist and developer that can be used to pattern the device features smaller than 100 nm.

  18. Parallel tempering Monte Carlo in LAMMPS.

    SciTech Connect

    Rintoul, Mark Daniel; Plimpton, Steven James; Sears, Mark P.

    2003-11-01

    We present here the details of the implementation of the parallel tempering Monte Carlo technique into a LAMMPS, a heavily used massively parallel molecular dynamics code at Sandia. This technique allows for many replicas of a system to be run at different simulation temperatures. At various points in the simulation, configurations can be swapped between different temperature environments and then continued. This allows for large regions of energy space to be sampled very quickly, and allows for minimum energy configurations to emerge in very complex systems, such as large biomolecular systems. By including this algorithm into an existing code, we immediately gain all of the previous work that had been put into LAMMPS, and allow this technique to quickly be available to the entire Sandia and international LAMMPS community. Finally, we present an example of this code applied to folding a small protein.

  19. Geometric Monte Carlo and black Janus geometries

    NASA Astrophysics Data System (ADS)

    Bak, Dongsu; Kim, Chanju; Kim, Kyung Kiu; Min, Hyunsoo; Song, Jeong-Pil

    2017-04-01

    We describe an application of the Monte Carlo method to the Janus deformation of the black brane background. We present numerical results for three and five dimensional black Janus geometries with planar and spherical interfaces. In particular, we argue that the 5D geometry with a spherical interface has an application in understanding the finite temperature bag-like QCD model via the AdS/CFT correspondence. The accuracy and convergence of the algorithm are evaluated with respect to the grid spacing. The systematic errors of the method are determined using an exact solution of 3D black Janus. This numerical approach for solving linear problems is unaffected initial guess of a trial solution and can handle an arbitrary geometry under various boundary conditions in the presence of source fields.

  20. Monte Carlo simulations of medical imaging modalities

    SciTech Connect

    Estes, G.P.

    1998-09-01

    Because continuous-energy Monte Carlo radiation transport calculations can be nearly exact simulations of physical reality (within data limitations, geometric approximations, transport algorithms, etc.), it follows that one should be able to closely approximate the results of many experiments from first-principles computations. This line of reasoning has led to various MCNP studies that involve simulations of medical imaging modalities and other visualization methods such as radiography, Anger camera, computerized tomography (CT) scans, and SABRINA particle track visualization. It is the intent of this paper to summarize some of these imaging simulations in the hope of stimulating further work, especially as computer power increases. Improved interpretation and prediction of medical images should ultimately lead to enhanced medical treatments. It is also reasonable to assume that such computations could be used to design new or more effective imaging instruments.

  1. Markov Chain Monte Carlo from Lagrangian Dynamics

    PubMed Central

    Lan, Shiwei; Stathopoulos, Vasileios; Shahbaba, Babak; Girolami, Mark

    2014-01-01

    Hamiltonian Monte Carlo (HMC) improves the computational e ciency of the Metropolis-Hastings algorithm by reducing its random walk behavior. Riemannian HMC (RHMC) further improves the performance of HMC by exploiting the geometric properties of the parameter space. However, the geometric integrator used for RHMC involves implicit equations that require fixed-point iterations. In some cases, the computational overhead for solving implicit equations undermines RHMC's benefits. In an attempt to circumvent this problem, we propose an explicit integrator that replaces the momentum variable in RHMC by velocity. We show that the resulting transformation is equivalent to transforming Riemannian Hamiltonian dynamics to Lagrangian dynamics. Experimental results suggests that our method improves RHMC's overall computational e ciency in the cases considered. All computer programs and data sets are available online (http://www.ics.uci.edu/~babaks/Site/Codes.html) in order to allow replication of the results reported in this paper. PMID:26240515

  2. Exploring theory space with Monte Carlo reweighting

    SciTech Connect

    Gainer, James S.; Lykken, Joseph; Matchev, Konstantin T.; Mrenna, Stephen; Park, Myeonghun

    2014-10-13

    Theories of new physics often involve a large number of unknown parameters which need to be scanned. Additionally, a putative signal in a particular channel may be due to a variety of distinct models of new physics. This makes experimental attempts to constrain the parameter space of motivated new physics models with a high degree of generality quite challenging. We describe how the reweighting of events may allow this challenge to be met, as fully simulated Monte Carlo samples generated for arbitrary benchmark models can be effectively re-used. Specifically, we suggest procedures that allow more efficient collaboration between theorists and experimentalists in exploring large theory parameter spaces in a rigorous way at the LHC.

  3. Accelerated GPU based SPECT Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

    2016-06-01

    Monte Carlo (MC) modelling is widely used in the field of single photon emission computed tomography (SPECT) as it is a reliable technique to simulate very high quality scans. This technique provides very accurate modelling of the radiation transport and particle interactions in a heterogeneous medium. Various MC codes exist for nuclear medicine imaging simulations. Recently, new strategies exploiting the computing capabilities of graphical processing units (GPU) have been proposed. This work aims at evaluating the accuracy of such GPU implementation strategies in comparison to standard MC codes in the context of SPECT imaging. GATE was considered the reference MC toolkit and used to evaluate the performance of newly developed GPU Geant4-based Monte Carlo simulation (GGEMS) modules for SPECT imaging. Radioisotopes with different photon energies were used with these various CPU and GPU Geant4-based MC codes in order to assess the best strategy for each configuration. Three different isotopes were considered: 99m Tc, 111In and 131I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational efficiency

  4. Monte Carlo scatter correction for SPECT

    NASA Astrophysics Data System (ADS)

    Liu, Zemei

    The goal of this dissertation is to present a quantitatively accurate and computationally fast scatter correction method that is robust and easily accessible for routine applications in SPECT imaging. A Monte Carlo based scatter estimation method is investigated and developed further. The Monte Carlo simulation program SIMIND (Simulating Medical Imaging Nuclear Detectors), was specifically developed to simulate clinical SPECT systems. The SIMIND scatter estimation (SSE) method was developed further using a multithreading technique to distribute the scatter estimation task across multiple threads running concurrently on multi-core CPU's to accelerate the scatter estimation process. An analytical collimator that ensures less noise was used during SSE. The research includes the addition to SIMIND of charge transport modeling in cadmium zinc telluride (CZT) detectors. Phenomena associated with radiation-induced charge transport including charge trapping, charge diffusion, charge sharing between neighboring detector pixels, as well as uncertainties in the detection process are addressed. Experimental measurements and simulation studies were designed for scintillation crystal based SPECT and CZT based SPECT systems to verify and evaluate the expanded SSE method. Jaszczak Deluxe and Anthropomorphic Torso Phantoms (Data Spectrum Corporation, Hillsborough, NC, USA) were used for experimental measurements and digital versions of the same phantoms employed during simulations to mimic experimental acquisitions. This study design enabled easy comparison of experimental and simulated data. The results have consistently shown that the SSE method performed similarly or better than the triple energy window (TEW) and effective scatter source estimation (ESSE) methods for experiments on all the clinical SPECT systems. The SSE method is proven to be a viable method for scatter estimation for routine clinical use.

  5. Accelerated GPU based SPECT Monte Carlo simulations.

    PubMed

    Garcia, Marie-Paule; Bert, Julien; Benoit, Didier; Bardiès, Manuel; Visvikis, Dimitris

    2016-06-07

    Monte Carlo (MC) modelling is widely used in the field of single photon emission computed tomography (SPECT) as it is a reliable technique to simulate very high quality scans. This technique provides very accurate modelling of the radiation transport and particle interactions in a heterogeneous medium. Various MC codes exist for nuclear medicine imaging simulations. Recently, new strategies exploiting the computing capabilities of graphical processing units (GPU) have been proposed. This work aims at evaluating the accuracy of such GPU implementation strategies in comparison to standard MC codes in the context of SPECT imaging. GATE was considered the reference MC toolkit and used to evaluate the performance of newly developed GPU Geant4-based Monte Carlo simulation (GGEMS) modules for SPECT imaging. Radioisotopes with different photon energies were used with these various CPU and GPU Geant4-based MC codes in order to assess the best strategy for each configuration. Three different isotopes were considered: (99m) Tc, (111)In and (131)I, using a low energy high resolution (LEHR) collimator, a medium energy general purpose (MEGP) collimator and a high energy general purpose (HEGP) collimator respectively. Point source, uniform source, cylindrical phantom and anthropomorphic phantom acquisitions were simulated using a model of the GE infinia II 3/8" gamma camera. Both simulation platforms yielded a similar system sensitivity and image statistical quality for the various combinations. The overall acceleration factor between GATE and GGEMS platform derived from the same cylindrical phantom acquisition was between 18 and 27 for the different radioisotopes. Besides, a full MC simulation using an anthropomorphic phantom showed the full potential of the GGEMS platform, with a resulting acceleration factor up to 71. The good agreement with reference codes and the acceleration factors obtained support the use of GPU implementation strategies for improving computational

  6. A Regional View of the Libya Montes

    NASA Technical Reports Server (NTRS)

    2000-01-01

    [figure removed for brevity, see original site]

    The Libya Montes are a ring of mountains up-lifted by the giant impact that created the Isidis basin to the north. During 1999, this region became one of the top two that were being considered for the now-canceled Mars Surveyor 2001 Lander. The Isidis basin is very, very ancient. Thus, the mountains that form its rims would contain some of the oldest rocks available at the Martian surface, and a landing in this region might potentially provide information about conditions on early Mars. In May 1999, the wide angle cameras of the Mars Global Surveyor Mars Orbiter Camera system were used in what was called the 'Geodesy Campaign' to obtain nearly global maps of the planet in color and in stereo at resolutions of 240 m/pixel (787 ft/pixel) for the red camera and 480 m/pixel (1575 ft/pixel) for the blue. Shown here are color and stereo views constructed from mosaics of the Geodesy Campaign images for the Libya Montes region of Mars. After they formed by giant impact, the Libya Mountains and valleys were subsequently modified and eroded by other processes, including wind, impact cratering, and flow of liquid water to make the many small valleys that can be seen running northward in the scene. The pictures shown here cover nearly 122,000 square kilometers (47,000 square miles) between latitudes 0.1oN and 4.0oN, longitudes 271.5oW and 279.9oW. The mosaics are about 518 km (322 mi) wide by 235 km (146 mi)high. Red-blue '3-D' glasses are needed to view the stereo image.

  7. Parton shower Monte Carlo event generators

    NASA Astrophysics Data System (ADS)

    Webber, Bryan

    2011-12-01

    A parton shower Monte Carlo event generator is a computer program designed to simulate the final states of high-energy collisions in full detail down to the level of individual stable particles. The aim is to generate a large number of simulated collision events, each consisting of a list of final-state particles and their momenta, such that the probability to produce an event with a given list is proportional (approximately) to the probability that the corresponding actual event is produced in the real world. The Monte Carlo method makes use of pseudorandom numbers to simulate the event-to-event fluctuations intrinsic to quantum processes. The simulation normally begins with a hard subprocess, shown as a black blob in Figure 1, in which constituents of the colliding particles interact at a high momentum scale to produce a few outgoing fundamental objects: Standard Model quarks, leptons and/or gauge or Higgs bosons, or hypothetical particles of some new theory. The partons (quarks and gluons) involved, as well as any new particles with colour, radiate virtual gluons, which can themselves emit further gluons or produce quark-antiquark pairs, leading to the formation of parton showers (brown). During parton showering the interaction scale falls and the strong interaction coupling rises, eventually triggering the process of hadronization (yellow), in which the partons are bound into colourless hadrons. On the same scale, the initial-state partons in hadronic collisions are confined in the incoming hadrons. In hadron-hadron collisions, the other constituent partons of the incoming hadrons undergo multiple interactions which produce the underlying event (green). Many of the produced hadrons are unstable, so the final stage of event generation is the simulation of the hadron decays.

  8. Fission Matrix Capability for MCNP Monte Carlo

    SciTech Connect

    Carney, Sean E.; Brown, Forrest B.; Kiedrowski, Brian C.; Martin, William R.

    2012-09-05

    In a Monte Carlo criticality calculation, before the tallying of quantities can begin, a converged fission source (the fundamental eigenvector of the fission kernel) is required. Tallies of interest may include powers, absorption rates, leakage rates, or the multiplication factor (the fundamental eigenvalue of the fission kernel, k{sub eff}). Just as in the power iteration method of linear algebra, if the dominance ratio (the ratio of the first and zeroth eigenvalues) is high, many iterations of neutron history simulations are required to isolate the fundamental mode of the problem. Optically large systems have large dominance ratios, and systems containing poor neutron communication between regions are also slow to converge. The fission matrix method, implemented into MCNP[1], addresses these problems. When Monte Carlo random walk from a source is executed, the fission kernel is stochastically applied to the source. Random numbers are used for: distances to collision, reaction types, scattering physics, fission reactions, etc. This method is used because the fission kernel is a complex, 7-dimensional operator that is not explicitly known. Deterministic methods use approximations/discretization in energy, space, and direction to the kernel. Consequently, they are faster. Monte Carlo directly simulates the physics, which necessitates the use of random sampling. Because of this statistical noise, common convergence acceleration methods used in deterministic methods do not work. In the fission matrix method, we are using the random walk information not only to build the next-iteration fission source, but also a spatially-averaged fission kernel. Just like in deterministic methods, this involves approximation and discretization. The approximation is the tallying of the spatially-discretized fission kernel with an incorrect fission source. We address this by making the spatial mesh fine enough that this error is negligible. As a consequence of discretization we get a

  9. 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.

  10. Reconstruction of Monte Carlo replicas from Hessian parton distributions

    NASA Astrophysics Data System (ADS)

    Hou, Tie-Jiun; Gao, Jun; Huston, Joey; Nadolsky, Pavel; Schmidt, Carl; Stump, Daniel; Wang, Bo-Ting; Xie, Ke Ping; Dulat, Sayipjamal; Pumplin, Jon; Yuan, C. P.

    2017-03-01

    We explore connections between two common methods for quantifying the uncertainty in parton distribution functions (PDFs), based on the Hessian error matrix and Monte-Carlo sampling. CT14 parton distributions in the Hessian representation are converted into Monte-Carlo replicas by a numerical method that reproduces important properties of CT14 Hessian PDFs: the asymmetry of CT14 uncertainties and positivity of individual parton distributions. The ensembles of CT14 Monte-Carlo replicas constructed this way at NNLO and NLO are suitable for various collider applications, such as cross section reweighting. Master formulas for computation of asymmetric standard deviations in the Monte-Carlo representation are derived. A correction is proposed to address a bias in asymmetric uncertainties introduced by the Taylor series approximation. A numerical program is made available for conversion of Hessian PDFs into Monte-Carlo replicas according to normal, log-normal, and Watt-Thorne sampling procedures.

  11. Iterative acceleration methods for Monte Carlo and deterministic criticality calculations

    SciTech Connect

    Urbatsch, T.J.

    1995-11-01

    If you have ever given up on a nuclear criticality calculation and terminated it because it took so long to converge, you might find this thesis of interest. The author develops three methods for improving the fission source convergence in nuclear criticality calculations for physical systems with high dominance ratios for which convergence is slow. The Fission Matrix Acceleration Method and the Fission Diffusion Synthetic Acceleration (FDSA) Method are acceleration methods that speed fission source convergence for both Monte Carlo and deterministic methods. The third method is a hybrid Monte Carlo method that also converges for difficult problems where the unaccelerated Monte Carlo method fails. The author tested the feasibility of all three methods in a test bed consisting of idealized problems. He has successfully accelerated fission source convergence in both deterministic and Monte Carlo criticality calculations. By filtering statistical noise, he has incorporated deterministic attributes into the Monte Carlo calculations in order to speed their source convergence. He has used both the fission matrix and a diffusion approximation to perform unbiased accelerations. The Fission Matrix Acceleration method has been implemented in the production code MCNP and successfully applied to a real problem. When the unaccelerated calculations are unable to converge to the correct solution, they cannot be accelerated in an unbiased fashion. A Hybrid Monte Carlo method weds Monte Carlo and a modified diffusion calculation to overcome these deficiencies. The Hybrid method additionally possesses reduced statistical errors.

  12. Atomistic Monte Carlo Simulation of Lipid Membranes

    PubMed Central

    Wüstner, Daniel; Sklenar, Heinz

    2014-01-01

    Biological membranes are complex assemblies of many different molecules of which analysis demands a variety of experimental and computational approaches. In this article, we explain challenges and advantages of atomistic Monte Carlo (MC) simulation of lipid membranes. We provide an introduction into the various move sets that are implemented in current MC methods for efficient conformational sampling of lipids and other molecules. In the second part, we demonstrate for a concrete example, how an atomistic local-move set can be implemented for MC simulations of phospholipid monomers and bilayer patches. We use our recently devised chain breakage/closure (CBC) local move set in the bond-/torsion angle space with the constant-bond-length approximation (CBLA) for the phospholipid dipalmitoylphosphatidylcholine (DPPC). We demonstrate rapid conformational equilibration for a single DPPC molecule, as assessed by calculation of molecular energies and entropies. We also show transition from a crystalline-like to a fluid DPPC bilayer by the CBC local-move MC method, as indicated by the electron density profile, head group orientation, area per lipid, and whole-lipid displacements. We discuss the potential of local-move MC methods in combination with molecular dynamics simulations, for example, for studying multi-component lipid membranes containing cholesterol. PMID:24469314

  13. Monte Carlo simulation of chromatin stretching

    NASA Astrophysics Data System (ADS)

    Aumann, Frank; Lankas, Filip; Caudron, Maïwen; Langowski, Jörg

    2006-04-01

    We present Monte Carlo (MC) simulations of the stretching of a single 30nm chromatin fiber. The model approximates the DNA by a flexible polymer chain with Debye-Hückel electrostatics and uses a two-angle zigzag model for the geometry of the linker DNA connecting the nucleosomes. The latter are represented by flat disks interacting via an attractive Gay-Berne potential. Our results show that the stiffness of the chromatin fiber strongly depends on the linker DNA length. Furthermore, changing the twisting angle between nucleosomes from 90° to 130° increases the stiffness significantly. An increase in the opening angle from 22° to 34° leads to softer fibers for small linker lengths. We observe that fibers containing a linker histone at each nucleosome are stiffer compared to those without the linker histone. The simulated persistence lengths and elastic moduli agree with experimental data. Finally, we show that the chromatin fiber does not behave as an isotropic elastic rod, but its rigidity depends on the direction of deformation: Chromatin is much more resistant to stretching than to bending.

  14. Monte Carlo simulations of Protein Adsorption

    NASA Astrophysics Data System (ADS)

    Sharma, Sumit; Kumar, Sanat K.; Belfort, Georges

    2008-03-01

    Amyloidogenic diseases, such as, Alzheimer's are caused by adsorption and aggregation of partially unfolded proteins. Adsorption of proteins is a concern in design of biomedical devices, such as dialysis membranes. Protein adsorption is often accompanied by conformational rearrangements in protein molecules. Such conformational rearrangements are thought to affect many properties of adsorbed protein molecules such as their adhesion strength to the surface, biological activity, and aggregation tendency. It has been experimentally shown that many naturally occurring proteins, upon adsorption to hydrophobic surfaces, undergo a helix to sheet or random coil secondary structural rearrangement. However, to better understand the equilibrium structural complexities of this phenomenon, we have performed Monte Carlo (MC) simulations of adsorption of a four helix bundle, modeled as a lattice protein, and studied the adsorption behavior and equilibrium protein conformations at different temperatures and degrees of surface hydrophobicity. To study the free energy and entropic effects on adsorption, Canonical ensemble MC simulations have been combined with Weighted Histogram Analysis Method(WHAM). Conformational transitions of proteins on surfaces will be discussed as a function of surface hydrophobicity and compared to analogous bulk transitions.

  15. Finding Planet Nine: a Monte Carlo approach

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2016-06-01

    Planet Nine is a hypothetical planet located well beyond Pluto that has been proposed in an attempt to explain the observed clustering in physical space of the perihelia of six extreme trans-Neptunian objects or ETNOs. The predicted approximate values of its orbital elements include a semimajor axis of 700 au, an eccentricity of 0.6, an inclination of 30°, and an argument of perihelion of 150°. Searching for this putative planet is already under way. Here, we use a Monte Carlo approach to create a synthetic population of Planet Nine orbits and study its visibility statistically in terms of various parameters and focusing on the aphelion configuration. Our analysis shows that, if Planet Nine exists and is at aphelion, it might be found projected against one out of the four specific areas in the sky. Each area is linked to a particular value of the longitude of the ascending node and two of them are compatible with an apsidal anti-alignment scenario. In addition and after studying the current statistics of ETNOs, a cautionary note on the robustness of the perihelia clustering is presented.

  16. Classical Trajectory and Monte Carlo Techniques

    NASA Astrophysics Data System (ADS)

    Olson, Ronald

    The classical trajectory Monte Carlo (CTMC) method originated with Hirschfelder, who studied the H + D2 exchange reaction using a mechanical calculator [58.1]. With the availability of computers, the CTMC method was actively applied to a large number of chemical systems to determine reaction rates, and final state vibrational and rotational populations (see, e.g., Karplus et al. [58.2]). For atomic physics problems, a major step was introduced by Abrines and Percival [58.3] who employed Kepler's equations and the Bohr-Sommerfield model for atomic hydrogen to investigate electron capture and ionization for intermediate velocity collisions of H+ + H. An excellent description is given by Percival and Richards [58.4]. The CTMC method has a wide range of applicability to strongly-coupled systems, such as collisions by multiply-charged ions [58.5]. In such systems, perturbation methods fail, and basis set limitations of coupled-channel molecular- and atomic-orbital techniques have difficulty in representing the multitude of activeexcitation, electron capture, and ionization channels. Vector- and parallel-processors now allow increasingly detailed study of the dynamics of the heavy projectile and target, along with the active electrons.

  17. Monte Carlo Simulation of Surface Reactions

    NASA Astrophysics Data System (ADS)

    Brosilow, Benjamin J.

    A Monte-Carlo study of the catalytic reaction of CO and O_2 over transition metal surfaces is presented, using generalizations of a model proposed by Ziff, Gulari and Barshad (ZGB). A new "constant -coverage" algorithm is described and applied to the model in order to elucidate the behavior near the model's first -order transition, and to draw an analogy between this transition and first-order phase transitions in equilibrium systems. The behavior of the model is then compared to the behavior of CO oxidation systems over Pt single-crystal catalysts. This comparison leads to the introduction of a new variation of the model in which one of the reacting species requires a large ensemble of vacant surface sites in order to adsorb. Further, it is shown that precursor adsorption and an effective Eley-Rideal mechanism must also be included in the model in order to obtain detailed agreement with experiment. Finally, variations of the model on finite and two component lattices are studied as models for low temperature CO oxidation over Noble Metal/Reducible Oxide and alloy catalysts.

  18. Hot Dog and Butterfly, Nereidum Montes

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Some of the pictures returned from Mars by the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft show features that--at a glance--resemble familiar, non-geological objects on Earth. For example, the picture above at the left shows several low, relatively flat-topped hills (mesas) on the floor of a broad valley among the mountains of the Nereidum Montes region, northeast of Argyre Planitia. One of the mesas seen here looks like half of a butterfly (upper subframe on right). Another hill looks something like a snail or a hot dog wrapped and baked in a croissant roll (lower subframe on right). These mesas were formed by natural processes and are most likely the eroded remnants of a formerly more extensive layer of bedrock. In the frame on the left, illumination is from the upper left and the scene covers an area 2.7 km (1.7 miles) wide by 6.8 km (4.2 miles) high. The 'butterfly' is about 800 meters (875 yards) in length and the 'hot dog' is about 1 km (0.62 miles) long.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  19. Markov Chain Monte Carlo and Irreversibility

    NASA Astrophysics Data System (ADS)

    Ottobre, Michela

    2016-06-01

    Markov Chain Monte Carlo (MCMC) methods are statistical methods designed to sample from a given measure π by constructing a Markov chain that has π as invariant measure and that converges to π. Most MCMC algorithms make use of chains that satisfy the detailed balance condition with respect to π; such chains are therefore reversible. On the other hand, recent work [18, 21, 28, 29] has stressed several advantages of using irreversible processes for sampling. Roughly speaking, irreversible diffusions converge to equilibrium faster (and lead to smaller asymptotic variance as well). In this paper we discuss some of the recent progress in the study of nonreversible MCMC methods. In particular: i) we explain some of the difficulties that arise in the analysis of nonreversible processes and we discuss some analytical methods to approach the study of continuous-time irreversible diffusions; ii) most of the rigorous results on irreversible diffusions are available for continuous-time processes; however, for computational purposes one needs to discretize such dynamics. It is well known that the resulting discretized chain will not, in general, retain all the good properties of the process that it is obtained from. In particular, if we want to preserve the invariance of the target measure, the chain might no longer be reversible. Therefore iii) we conclude by presenting an MCMC algorithm, the SOL-HMC algorithm [23], which results from a nonreversible discretization of a nonreversible dynamics.

  20. Commensurabilities between ETNOs: a Monte Carlo survey

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2016-07-01

    Many asteroids in the main and trans-Neptunian belts are trapped in mean motion resonances with Jupiter and Neptune, respectively. As a side effect, they experience accidental commensurabilities among themselves. These commensurabilities define characteristic patterns that can be used to trace the source of the observed resonant behaviour. Here, we explore systematically the existence of commensurabilities between the known ETNOs using their heliocentric and barycentric semimajor axes, their uncertainties, and Monte Carlo techniques. We find that the commensurability patterns present in the known ETNO population resemble those found in the main and trans-Neptunian belts. Although based on small number statistics, such patterns can only be properly explained if most, if not all, of the known ETNOs are subjected to the resonant gravitational perturbations of yet undetected trans-Plutonian planets. We show explicitly that some of the statistically significant commensurabilities are compatible with the Planet Nine hypothesis; in particular, a number of objects may be trapped in the 5:3 and 3:1 mean motion resonances with a putative Planet Nine with semimajor axis ˜700 au.

  1. Combinatorial geometry domain decomposition strategies for Monte Carlo simulations

    SciTech Connect

    Li, G.; Zhang, B.; Deng, L.; Mo, Z.; Liu, Z.; Shangguan, D.; Ma, Y.; Li, S.; Hu, Z.

    2013-07-01

    Analysis and modeling of nuclear reactors can lead to memory overload for a single core processor when it comes to refined modeling. A method to solve this problem is called 'domain decomposition'. In the current work, domain decomposition algorithms for a combinatorial geometry Monte Carlo transport code are developed on the JCOGIN (J Combinatorial Geometry Monte Carlo transport INfrastructure). Tree-based decomposition and asynchronous communication of particle information between domains are described in the paper. Combination of domain decomposition and domain replication (particle parallelism) is demonstrated and compared with that of MERCURY code. A full-core reactor model is simulated to verify the domain decomposition algorithms using the Monte Carlo particle transport code JMCT (J Monte Carlo Transport Code), which has being developed on the JCOGIN infrastructure. Besides, influences of the domain decomposition algorithms to tally variances are discussed. (authors)

  2. Bayesian phylogeny analysis via stochastic approximation Monte Carlo.

    PubMed

    Cheon, Sooyoung; Liang, Faming

    2009-11-01

    Monte Carlo methods have received much attention in the recent literature of phylogeny analysis. However, the conventional Markov chain Monte Carlo algorithms, such as the Metropolis-Hastings algorithm, tend to get trapped in a local mode in simulating from the posterior distribution of phylogenetic trees, rendering the inference ineffective. In this paper, we apply an advanced Monte Carlo algorithm, the stochastic approximation Monte Carlo algorithm, to Bayesian phylogeny analysis. Our method is compared with two popular Bayesian phylogeny software, BAMBE and MrBayes, on simulated and real datasets. The numerical results indicate that our method outperforms BAMBE and MrBayes. Among the three methods, SAMC produces the consensus trees which have the highest similarity to the true trees, and the model parameter estimates which have the smallest mean square errors, but costs the least CPU time.

  3. Monte Carlo variance reduction approaches for non-Boltzmann tallies

    SciTech Connect

    Booth, T.E.

    1992-12-01

    Quantities that depend on the collective effects of groups of particles cannot be obtained from the standard Boltzmann transport equation. Monte Carlo estimates of these quantities are called non-Boltzmann tallies and have become increasingly important recently. Standard Monte Carlo variance reduction techniques were designed for tallies based on individual particles rather than groups of particles. Experience with non-Boltzmann tallies and analog Monte Carlo has demonstrated the severe limitations of analog Monte Carlo for many non-Boltzmann tallies. In fact, many calculations absolutely require variance reduction methods to achieve practical computation times. Three different approaches to variance reduction for non-Boltzmann tallies are described and shown to be unbiased. The advantages and disadvantages of each of the approaches are discussed.

  4. OBJECT KINETIC MONTE CARLO SIMULATIONS OF CASCADE ANNEALING IN TUNGSTEN

    SciTech Connect

    Nandipati, Giridhar; Setyawan, Wahyu; Heinisch, Howard L.; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2014-03-31

    The objective of this work is to study the annealing of primary cascade damage created by primary knock-on atoms (PKAs) of various energies, at various temperatures in bulk tungsten using the object kinetic Monte Carlo (OKMC) method.

  5. Monte Carlo simulations: Hidden errors from ``good'' random number generators

    NASA Astrophysics Data System (ADS)

    Ferrenberg, Alan M.; Landau, D. P.; Wong, Y. Joanna

    1992-12-01

    The Wolff algorithm is now accepted as the best cluster-flipping Monte Carlo algorithm for beating ``critical slowing down.'' We show how this method can yield incorrect answers due to subtle correlations in ``high quality'' random number generators.

  6. Monte Carlo next-event estimates from thermal collisions

    SciTech Connect

    Hendricks, J.S.; Prael, R.E.

    1990-01-01

    A new approximate method has been developed by Richard E. Prael to allow S({alpha},{beta}) thermal collision contributions to next-event estimators in Monte Carlo calculations. The new technique is generally applicable to next-event estimator contributions from any discrete probability distribution. The method has been incorporated into Version 4 of the production Monte Carlo neutron and photon radiation transport code MCNP. 9 refs.

  7. Multiscale Monte Carlo equilibration: Pure Yang-Mills theory

    NASA Astrophysics Data System (ADS)

    Endres, Michael G.; Brower, Richard C.; Detmold, William; Orginos, Kostas; Pochinsky, Andrew V.

    2015-12-01

    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.

  8. Development of Monte Carlo Capability for Orion Parachute Simulations

    NASA Technical Reports Server (NTRS)

    Moore, James W.

    2011-01-01

    Parachute test programs employ Monte Carlo simulation techniques to plan testing and make critical decisions related to parachute loads, rate-of-descent, or other parameters. This paper describes the development and use of a MATLAB-based Monte Carlo tool for three parachute drop test simulations currently used by NASA. The Decelerator System Simulation (DSS) is a legacy 6 Degree-of-Freedom (DOF) simulation used to predict parachute loads and descent trajectories. The Decelerator System Simulation Application (DSSA) is a 6-DOF simulation that is well suited for modeling aircraft extraction and descent of pallet-like test vehicles. The Drop Test Vehicle Simulation (DTVSim) is a 2-DOF trajectory simulation that is convenient for quick turn-around analysis tasks. These three tools have significantly different software architectures and do not share common input files or output data structures. Separate Monte Carlo tools were initially developed for each simulation. A recently-developed simulation output structure enables the use of the more sophisticated DSSA Monte Carlo tool with any of the core-simulations. The task of configuring the inputs for the nominal simulation is left to the existing tools. Once the nominal simulation is configured, the Monte Carlo tool perturbs the input set according to dispersion rules created by the analyst. These rules define the statistical distribution and parameters to be applied to each simulation input. Individual dispersed parameters are combined to create a dispersed set of simulation inputs. The Monte Carlo tool repeatedly executes the core-simulation with the dispersed inputs and stores the results for analysis. The analyst may define conditions on one or more output parameters at which to collect data slices. The tool provides a versatile interface for reviewing output of large Monte Carlo data sets while preserving the capability for detailed examination of individual dispersed trajectories. The Monte Carlo tool described in

  9. Improved Collision Modeling for Direct Simulation Monte Carlo Methods

    DTIC Science & Technology

    2011-03-01

    number is a measure of the rarefaction of a gas , and will be explained more thoroughly in the following chap- ter. Continuum solvers that use Navier...Limits on Mathematical Models [4] Kn=0.1, and the flow can be considered rarefied above that value. Direct Simulation Monte Carlo (DSMC) is a stochastic...method which utilizes the Monte Carlo statistical model to simulate gas behavior, which is very useful for these rarefied atmosphere hypersonic

  10. 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.

  11. Confidence and efficiency scaling in variational quantum Monte Carlo calculations

    NASA Astrophysics Data System (ADS)

    Delyon, F.; Bernu, B.; Holzmann, Markus

    2017-02-01

    Based on the central limit theorem, we discuss the problem of evaluation of the statistical error of Monte Carlo calculations using a time-discretized diffusion process. We present a robust and practical method to determine the effective variance of general observables and show how to verify the equilibrium hypothesis by the Kolmogorov-Smirnov test. We then derive scaling laws of the efficiency illustrated by variational Monte Carlo calculations on the two-dimensional electron gas.

  12. CosmoPMC: Cosmology sampling with Population Monte Carlo

    NASA Astrophysics Data System (ADS)

    Kilbinger, Martin; Benabed, Karim; Cappé, Olivier; Coupon, Jean; Cardoso, Jean-François; Fort, Gersende; McCracken, Henry Joy; Prunet, Simon; Robert, Christian P.; Wraith, Darren

    2012-12-01

    CosmoPMC is a Monte-Carlo sampling method to explore the likelihood of various cosmological probes. The sampling engine is implemented with the package pmclib. It is called Population MonteCarlo (PMC), which is a novel technique to sample from the posterior. PMC is an adaptive importance sampling method which iteratively improves the proposal to approximate the posterior. This code has been introduced, tested and applied to various cosmology data sets.

  13. The Mont Blanc detection of neutrinos from SN 1987A.

    NASA Astrophysics Data System (ADS)

    Aglietta, M.; Badino, G.; Bologna, G.; Castagnoli, C.; Castellina, A.; Dadykin, V. L.; Fulgione, W.; Galeotti, P.; Kalchukov, F. F.; Kortchaguin, V. B.; Kortchaguin, P. V.; Malguin, A. S.; Ryassny, V. G.; Ryazhkaya, O. G.; Saavedra, O.; Talochkin, V. P.; Trinchero, G.; Vernetto, S.; Zatsepin, G. T.; Yakushev, V. F.

    The authors discuss the event detected in the Mont Blanc Underground Neutrino Observatory on February 23, 1987, during the occurrence of supernova SN 1987A. The pulse amplitudes, the background imitation probability, and the energetics connected with the event are reported. It is also shown that some interactions recorded at the same time in other underground experiments, with a lower detection efficiency, are consistent with the Mont Blanc event.

  14. Green's function Monte Carlo calculations of /sup 4/He

    SciTech Connect

    Carlson, J.A.

    1988-01-01

    Green's Function Monte Carlo methods have been developed to study the ground state properties of light nuclei. These methods are shown to reproduce results of Faddeev calculations for A = 3, and are then used to calculate ground state energies, one- and two-body distribution functions, and the D-state probability for the alpha particle. Results are compared to variational Monte Carlo calculations for several nuclear interaction models. 31 refs.

  15. Successful combination of the stochastic linearization and Monte Carlo methods

    NASA Technical Reports Server (NTRS)

    Elishakoff, I.; Colombi, P.

    1993-01-01

    A combination of a stochastic linearization and Monte Carlo techniques is presented for the first time in literature. A system with separable nonlinear damping and nonlinear restoring force is considered. The proposed combination of the energy-wise linearization with the Monte Carlo method yields an error under 5 percent, which corresponds to the error reduction associated with the conventional stochastic linearization by a factor of 4.6.

  16. de Finetti Priors using Markov chain Monte Carlo computations.

    PubMed

    Bacallado, Sergio; Diaconis, Persi; Holmes, Susan

    2015-07-01

    Recent advances in Monte Carlo methods allow us to revisit work by de Finetti who suggested the use of approximate exchangeability in the analyses of contingency tables. This paper gives examples of computational implementations using Metropolis Hastings, Langevin and Hamiltonian Monte Carlo to compute posterior distributions for test statistics relevant for testing independence, reversible or three way models for discrete exponential families using polynomial priors and Gröbner bases.

  17. de Finetti Priors using Markov chain Monte Carlo computations

    PubMed Central

    Bacallado, Sergio; Diaconis, Persi; Holmes, Susan

    2015-01-01

    Recent advances in Monte Carlo methods allow us to revisit work by de Finetti who suggested the use of approximate exchangeability in the analyses of contingency tables. This paper gives examples of computational implementations using Metropolis Hastings, Langevin and Hamiltonian Monte Carlo to compute posterior distributions for test statistics relevant for testing independence, reversible or three way models for discrete exponential families using polynomial priors and Gröbner bases. PMID:26412947

  18. Monte Carlo methods and applications in nuclear physics

    SciTech Connect

    Carlson, J.

    1990-01-01

    Monte Carlo methods for studying few- and many-body quantum systems are introduced, with special emphasis given to their applications in nuclear physics. Variational and Green's function Monte Carlo methods are presented in some detail. The status of calculations of light nuclei is reviewed, including discussions of the three-nucleon-interaction, charge and magnetic form factors, the coulomb sum rule, and studies of low-energy radiative transitions. 58 refs., 12 figs.

  19. Event-chain Monte Carlo for classical continuous spin models

    NASA Astrophysics Data System (ADS)

    Michel, Manon; Mayer, Johannes; Krauth, Werner

    2015-10-01

    We apply the event-chain Monte Carlo algorithm to classical continuum spin models on a lattice and clarify the condition for its validity. In the two-dimensional XY model, it outperforms the local Monte Carlo algorithm by two orders of magnitude, although it remains slower than the Wolff cluster algorithm. In the three-dimensional XY spin glass model at low temperature, the event-chain algorithm is far superior to the other algorithms.

  20. DPEMC: A Monte Carlo for double diffraction

    NASA Astrophysics Data System (ADS)

    Boonekamp, M.; Kúcs, T.

    2005-05-01

    We extend the POMWIG Monte Carlo generator developed by B. Cox and J. Forshaw, to include new models of central production through inclusive and exclusive double Pomeron exchange in proton-proton collisions. Double photon exchange processes are described as well, both in proton-proton and heavy-ion collisions. In all contexts, various models have been implemented, allowing for comparisons and uncertainty evaluation and enabling detailed experimental simulations. Program summaryTitle of the program:DPEMC, version 2.4 Catalogue identifier: ADVF Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADVF Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computer: any computer with the FORTRAN 77 compiler under the UNIX or Linux operating systems Operating system: UNIX; Linux Programming language used: FORTRAN 77 High speed storage required:<25 MB No. of lines in distributed program, including test data, etc.: 71 399 No. of bytes in distributed program, including test data, etc.: 639 950 Distribution format: tar.gz Nature of the physical problem: Proton diffraction at hadron colliders can manifest itself in many forms, and a variety of models exist that attempt to describe it [A. Bialas, P.V. Landshoff, Phys. Lett. B 256 (1991) 540; A. Bialas, W. Szeremeta, Phys. Lett. B 296 (1992) 191; A. Bialas, R.A. Janik, Z. Phys. C 62 (1994) 487; M. Boonekamp, R. Peschanski, C. Royon, Phys. Rev. Lett. 87 (2001) 251806; Nucl. Phys. B 669 (2003) 277; R. Enberg, G. Ingelman, A. Kissavos, N. Timneanu, Phys. Rev. Lett. 89 (2002) 081801; R. Enberg, G. Ingelman, L. Motyka, Phys. Lett. B 524 (2002) 273; R. Enberg, G. Ingelman, N. Timneanu, Phys. Rev. D 67 (2003) 011301; B. Cox, J. Forshaw, Comput. Phys. Comm. 144 (2002) 104; B. Cox, J. Forshaw, B. Heinemann, Phys. Lett. B 540 (2002) 26; V. Khoze, A. Martin, M. Ryskin, Phys. Lett. B 401 (1997) 330; Eur. Phys. J. C 14 (2000) 525; Eur. Phys. J. C 19 (2001) 477; Erratum, Eur. Phys. J. C 20 (2001) 599; Eur

  1. Perturbation Monte Carlo methods for tissue structure alterations.

    PubMed

    Nguyen, Jennifer; Hayakawa, Carole K; Mourant, Judith R; Spanier, Jerome

    2013-01-01

    This paper describes an extension of the perturbation Monte Carlo method to model light transport when the phase function is arbitrarily perturbed. Current perturbation Monte Carlo methods allow perturbation of both the scattering and absorption coefficients, however, the phase function can not be varied. The more complex method we develop and test here is not limited in this way. We derive a rigorous perturbation Monte Carlo extension that can be applied to a large family of important biomedical light transport problems and demonstrate its greater computational efficiency compared with using conventional Monte Carlo simulations to produce forward transport problem solutions. The gains of the perturbation method occur because only a single baseline Monte Carlo simulation is needed to obtain forward solutions to other closely related problems whose input is described by perturbing one or more parameters from the input of the baseline problem. The new perturbation Monte Carlo methods are tested using tissue light scattering parameters relevant to epithelia where many tumors originate. The tissue model has parameters for the number density and average size of three classes of scatterers; whole nuclei, organelles such as lysosomes and mitochondria, and small particles such as ribosomes or large protein complexes. When these parameters or the wavelength is varied the scattering coefficient and the phase function vary. Perturbation calculations give accurate results over variations of ∼15-25% of the scattering parameters.

  2. Implications of Monte Carlo Statistical Errors in Criticality Safety Assessments

    SciTech Connect

    Pevey, Ronald E.

    2005-09-15

    Most criticality safety calculations are performed using Monte Carlo techniques because of Monte Carlo's ability to handle complex three-dimensional geometries. For Monte Carlo calculations, the more histories sampled, the lower the standard deviation of the resulting estimates. The common intuition is, therefore, that the more histories, the better; as a result, analysts tend to run Monte Carlo analyses as long as possible (or at least to a minimum acceptable uncertainty). For Monte Carlo criticality safety analyses, however, the optimization situation is complicated by the fact that procedures usually require that an extra margin of safety be added because of the statistical uncertainty of the Monte Carlo calculations. This additional safety margin affects the impact of the choice of the calculational standard deviation, both on production and on safety. This paper shows that, under the assumptions of normally distributed benchmarking calculational errors and exact compliance with the upper subcritical limit (USL), the standard deviation that optimizes production is zero, but there is a non-zero value of the calculational standard deviation that minimizes the risk of inadvertently labeling a supercritical configuration as subcritical. Furthermore, this value is shown to be a simple function of the typical benchmarking step outcomes--the bias, the standard deviation of the bias, the upper subcritical limit, and the number of standard deviations added to calculated k-effectives before comparison to the USL.

  3. kmos: A lattice kinetic Monte Carlo framework

    NASA Astrophysics Data System (ADS)

    Hoffmann, Max J.; Matera, Sebastian; Reuter, Karsten

    2014-07-01

    Kinetic Monte Carlo (kMC) simulations have emerged as a key tool for microkinetic modeling in heterogeneous catalysis and other materials applications. Systems, where site-specificity of all elementary reactions allows a mapping onto a lattice of discrete active sites, can be addressed within the particularly efficient lattice kMC approach. To this end we describe the versatile kmos software package, which offers a most user-friendly implementation, execution, and evaluation of lattice kMC models of arbitrary complexity in one- to three-dimensional lattice systems, involving multiple active sites in periodic or aperiodic arrangements, as well as site-resolved pairwise and higher-order lateral interactions. Conceptually, kmos achieves a maximum runtime performance which is essentially independent of lattice size by generating code for the efficiency-determining local update of available events that is optimized for a defined kMC model. For this model definition and the control of all runtime and evaluation aspects kmos offers a high-level application programming interface. Usage proceeds interactively, via scripts, or a graphical user interface, which visualizes the model geometry, the lattice occupations and rates of selected elementary reactions, while allowing on-the-fly changes of simulation parameters. We demonstrate the performance and scaling of kmos with the application to kMC models for surface catalytic processes, where for given operation conditions (temperature and partial pressures of all reactants) central simulation outcomes are catalytic activity and selectivities, surface composition, and mechanistic insight into the occurrence of individual elementary processes in the reaction network.

  4. Lattice Monte Carlo simulations of polymer melts

    NASA Astrophysics Data System (ADS)

    Hsu, Hsiao-Ping

    2014-12-01

    We use Monte Carlo simulations to study polymer melts consisting of fully flexible and moderately stiff chains in the bond fluctuation model at a volume fraction 0.5. In order to reduce the local density fluctuations, we test a pre-packing process for the preparation of the initial configurations of the polymer melts, before the excluded volume interaction is switched on completely. This process leads to a significantly faster decrease of the number of overlapping monomers on the lattice. This is useful for simulating very large systems, where the statistical properties of the model with a marginally incomplete elimination of excluded volume violations are the same as those of the model with strictly excluded volume. We find that the internal mean square end-to-end distance for moderately stiff chains in a melt can be very well described by a freely rotating chain model with a precise estimate of the bond-bond orientational correlation between two successive bond vectors in equilibrium. The plot of the probability distributions of the reduced end-to-end distance of chains of different stiffness also shows that the data collapse is excellent and described very well by the Gaussian distribution for ideal chains. However, while our results confirm the systematic deviations between Gaussian statistics for the chain structure factor Sc(q) [minimum in the Kratky-plot] found by Wittmer et al. [EPL 77, 56003 (2007)] for fully flexible chains in a melt, we show that for the available chain length these deviations are no longer visible, when the chain stiffness is included. The mean square bond length and the compressibility estimated from collective structure factors depend slightly on the stiffness of the chains.

  5. Monte-Carlo simulation of Callisto's exosphere

    NASA Astrophysics Data System (ADS)

    Vorburger, A.; Wurz, P.; Lammer, H.; Barabash, S.; Mousis, O.

    2015-12-01

    We model Callisto's exosphere based on its ice as well as non-ice surface via the use of a Monte-Carlo exosphere model. For the ice component we implement two putative compositions that have been computed from two possible extreme formation scenarios of the satellite. One composition represents the oxidizing state and is based on the assumption that the building blocks of Callisto were formed in the protosolar nebula and the other represents the reducing state of the gas, based on the assumption that the satellite accreted from solids condensed in the jovian sub-nebula. For the non-ice component we implemented the compositions of typical CI as well as L type chondrites. Both chondrite types have been suggested to represent Callisto's non-ice composition best. As release processes we consider surface sublimation, ion sputtering and photon-stimulated desorption. Particles are followed on their individual trajectories until they either escape Callisto's gravitational attraction, return to the surface, are ionized, or are fragmented. Our density profiles show that whereas the sublimated species dominate close to the surface on the sun-lit side, their density profiles (with the exception of H and H2) decrease much more rapidly than the sputtered particles. The Neutral gas and Ion Mass (NIM) spectrometer, which is part of the Particle Environment Package (PEP), will investigate Callisto's exosphere during the JUICE mission. Our simulations show that NIM will be able to detect sublimated and sputtered particles from both the ice and non-ice surface. NIM's measured chemical composition will allow us to distinguish between different formation scenarios.

  6. Monte Carlo implementation of polarized hadronization

    NASA Astrophysics Data System (ADS)

    Matevosyan, Hrayr H.; Kotzinian, Aram; Thomas, Anthony W.

    2017-01-01

    We study the polarized quark hadronization in a Monte Carlo (MC) framework based on the recent extension of the quark-jet framework, where a self-consistent treatment of the quark polarization transfer in a sequential hadronization picture has been presented. Here, we first adopt this approach for MC simulations of the hadronization process with a finite number of produced hadrons, expressing the relevant probabilities in terms of the eight leading twist quark-to-quark transverse-momentum-dependent (TMD) splitting functions (SFs) for elementary q →q'+h transition. We present explicit expressions for the unpolarized and Collins fragmentation functions (FFs) of unpolarized hadrons emitted at rank 2. Further, we demonstrate that all the current spectator-type model calculations of the leading twist quark-to-quark TMD SFs violate the positivity constraints, and we propose a quark model based ansatz for these input functions that circumvents the problem. We validate our MC framework by explicitly proving the absence of unphysical azimuthal modulations of the computed polarized FFs, and by precisely reproducing the earlier derived explicit results for rank-2 pions. Finally, we present the full results for pion unpolarized and Collins FFs, as well as the corresponding analyzing powers from high statistics MC simulations with a large number of produced hadrons for two different model input elementary SFs. The results for both sets of input functions exhibit the same general features of an opposite signed Collins function for favored and unfavored channels at large z and, at the same time, demonstrate the flexibility of the quark-jet framework by producing significantly different dependences of the results at mid to low z for the two model inputs.

  7. Quantum Monte Carlo with directed loops.

    PubMed

    Syljuåsen, Olav F; Sandvik, Anders W

    2002-10-01

    We introduce the concept of directed loops in stochastic series expansion and path-integral quantum Monte Carlo methods. Using the detailed balance rules for directed loops, we show that it is possible to smoothly connect generally applicable simulation schemes (in which it is necessary to include backtracking processes in the loop construction) to more restricted loop algorithms that can be constructed only for a limited range of Hamiltonians (where backtracking can be avoided). The "algorithmic discontinuities" between general and special points (or regions) in parameter space can hence be eliminated. As a specific example, we consider the anisotropic S=1/2 Heisenberg antiferromagnet in an external magnetic field. We show that directed-loop simulations are very efficient for the full range of magnetic fields (zero to the saturation point) and anisotropies. In particular, for weak fields and anisotropies, the autocorrelations are significantly reduced relative to those of previous approaches. The back-tracking probability vanishes continuously as the isotropic Heisenberg point is approached. For the XY model, we show that back tracking can be avoided for all fields extending up to the saturation field. The method is hence particularly efficient in this case. We use directed-loop simulations to study the magnetization process in the two-dimensional Heisenberg model at very low temperatures. For LxL lattices with L up to 64, we utilize the step structure in the magnetization curve to extract gaps between different spin sectors. Finite-size scaling of the gaps gives an accurate estimate of the transverse susceptibility in the thermodynamic limit: chi( perpendicular )=0.0659+/-0.0002.

  8. Monte Carlo Volcano Seismic Moment Tensors

    NASA Astrophysics Data System (ADS)

    Waite, G. P.; Brill, K. A.; Lanza, F.

    2015-12-01

    Inverse modeling of volcano seismic sources can provide insight into the geometry and dynamics of volcanic conduits. But given the logistical challenges of working on an active volcano, seismic networks are typically deficient in spatial and temporal coverage; this potentially leads to large errors in source models. In addition, uncertainties in the centroid location and moment-tensor components, including volumetric components, are difficult to constrain from the linear inversion results, which leads to a poor understanding of the model space. In this study, we employ a nonlinear inversion using a Monte Carlo scheme with the objective of defining robustly resolved elements of model space. The model space is randomized by centroid location and moment tensor eigenvectors. Point sources densely sample the summit area and moment tensors are constrained to a randomly chosen geometry within the inversion; Green's functions for the random moment tensors are all calculated from modeled single forces, making the nonlinear inversion computationally reasonable. We apply this method to very-long-period (VLP) seismic events that accompany minor eruptions at Fuego volcano, Guatemala. The library of single force Green's functions is computed with a 3D finite-difference modeling algorithm through a homogeneous velocity-density model that includes topography, for a 3D grid of nodes, spaced 40 m apart, within the summit region. The homogenous velocity and density model is justified by long wavelength of VLP data. The nonlinear inversion reveals well resolved model features and informs the interpretation through a better understanding of the possible models. This approach can also be used to evaluate possible station geometries in order to optimize networks prior to deployment.

  9. Quantum Monte Carlo Endstation for Petascale Computing

    SciTech Connect

    David Ceperley

    2011-03-02

    CUDA GPU platform. We restructured the CPU algorithms to express additional parallelism, minimize GPU-CPU communication, and efficiently utilize the GPU memory hierarchy. Using mixed precision on GT200 GPUs and MPI for intercommunication and load balancing, we observe typical full-application speedups of approximately 10x to 15x relative to quad-core Xeon CPUs alone, while reproducing the double-precision CPU results within statistical error. We developed an all-electron quantum Monte Carlo (QMC) method for solids that does not rely on pseudopotentials, and used it to construct a primary ultra-high-pressure calibration based on the equation of state of cubic boron nitride. We computed the static contribution to the free energy with the QMC method and obtained the phonon contribution from density functional theory, yielding a high-accuracy calibration up to 900 GPa usable directly in experiment. We computed the anharmonic Raman frequency shift with QMC simulations as a function of pressure and temperature, allowing optical pressure calibration. In contrast to present experimental approaches, small systematic errors in the theoretical EOS do not increase with pressure, and no extrapolation is needed. This all-electron method is applicable to first-row solids, providing a new reference for ab initio calculations of solids and benchmarks for pseudopotential accuracy. We compared experimental and theoretical results on the momentum distribution and the quasiparticle renormalization factor in sodium. From an x-ray Compton-profile measurement of the valence-electron momentum density, we derived its discontinuity at the Fermi wavevector finding an accurate measure of the renormalization factor that we compared with quantum-Monte-Carlo and G0W0 calculations performed both on crystalline sodium and on the homogeneous electron gas. Our calculated results are in good agreement with the experiment. We have been studying the heat of formation for various Kubas complexes of molecular

  10. Men's Health and Spina Bifida

    MedlinePlus

    ... clinic about these. www.spinabildaassociation.org • 1600 Wilson Blvd. Suite 800 Arlington, VA 22209 • 800-621-3141 ... an individual basis. www.spinabildaassociation.org • 1600 Wilson Blvd. Suite 800 Arlington, VA 22209 • 800-621-3141

  11. Spina Bifida Data and Statistics

    MedlinePlus

    ... Materials About Us Information For... Media Policy Makers Data and Statistics Recommend on Facebook Tweet Share Compartir ... non-Hispanic white and non-Hispanic black women. Data from 12 state-based birth defects tracking programs ...

  12. Genetics Home Reference: spina bifida

    MedlinePlus

    ... when the spine forms, the bones of the spinal column do not close completely around the developing nerves ... severe, depending on where the opening in the spinal column is located and how much of the spinal ...

  13. Monte Carlo Techniques for Nuclear Systems - Theory Lectures

    SciTech Connect

    Brown, Forrest B.

    2016-11-29

    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. These 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 calculations

  14. Towards a detailed distal tephrostratigraphy in the Central Mediterranean: The last 20,000 yrs record of Lago Grande di Monticchio

    NASA Astrophysics Data System (ADS)

    Wulf, Sabine; Kraml, Michael; Keller, Jörg

    2008-10-01

    A detailed compilation of distal tephrostratigraphy comprising the last 20,000 yrs is given for the Central Mediterranean region. A total of 47 distinct ash layers identified in the maar lake sediments of Lago Grande di Monticchio (Basilicata, Southern Italy) are compared with proximal and distal terrestrial-marine tephra deposits in the circum-central Mediterranean region. The results of these studies provide valuable information for reconstructing the Late Pleistocene and the Holocene dispersal of pyroclastic deposits from south Italian explosive volcanoes, in particular Somma-Vesuvius, the Campi Flegrei caldera, Ischia Island and Mount Etna. Prominent tephras are discussed with respect to their reliability as dating and correlation tools in sedimentary records. Ashes from Plinian eruptions of Somma-Vesuvius (i.e. Avellino, Mercato, Greenish, Pomici di Base), for instance, are well-defined by their distribution patterns and their unique composition. The widespread Y-1 tephra from Mount Etna, on the other hand, derived most likely from two distinct Plinian events with changing wind conditions, and therefore becomes a less reliable stratigraphic marker. Statistical-numerical calculations are presented in order to discriminate between Holocene tephras from the Campi Flegrei caldera (i.e. Astroni 1-3, Agnano Monte Spina, Averno 1, Lagno Amendolare), since these ashes are characterized by an almost indistinguishable chemical fingerprint. As a highlight, numerous Campanian eruptions of proposed low-intensity have been identified in the distal site of Monticchio suggesting a revision of existing tephra dispersal maps and re-calculation of eruptive conditions. In summary, the tephra record of Monticchio is one of the key successions for linking both, terrestrial records from Central-southern Italy and marine sequences from the Tyrrhenian, Adriatic and Ionian Seas.

  15. The Astroni volcano: the only example of closely spaced eruptions in the same vent area during the recent history of the Campi Flegrei caldera (Italy)

    NASA Astrophysics Data System (ADS)

    Isaia, Roberto; D'Antonio, Massimo; Dell'Erba, Francesco; Di Vito, Mauro; Orsi, Giovanni

    2004-05-01

    The Astroni volcano formed during the third and most recent epoch of activity (4.8-3.8 ka) of the Campi Flegrei caldera (CFc). The activity of the volcano was dominated by explosive, mostly phreatomagmatic eruptions, with only subordinate lava effusions. We have grouped the sequence of deposits into seven distinct units, separated by erosional unconformities or very thin paleosols. The units include mostly surge beds, with subordinate strombolian deposits and lavas, and one plinian fallout layer. The total volume of erupted magma is 0.45 km 3 (DRE), while the total mass is 1.12×10 12 kg. The magma feeding the first five eruptions was alkali-trachytic and slightly zoned, while the last two eruptions tapped a magma batch resulting from mixing of the previously extruded alkali-trachytic and a less evolved trachytic magma. The volcano grew at the northwestern edge of the polygonal volcano-tectonic collapse, northwest-southeast elongated, which accompanied the Agnano-Monte Spina eruption (4.1 ka), the largest of the third epoch. Available radiometric dates and stratigraphical data constrain the age of the volcano in the final part of the 4.1-3.8 ka time span. This implies that the seven eruptions followed each other at very short time intervals. This conclusion is also supported by constancy in archaeological facies of findings within the paleosols between variable Astroni units, in the plain north of the caldera. The sequence of close eruptions in the same area, although with a slight migration of the vent from northwest to southeast, makes the Astroni volcano peculiar in the recent history of the CFc. Therefore, the definition of its history is very important in order to understand one of the past phenomenologies of the caldera, relevant elements to forecast its behavior.

  16. PYFLOW: A computer code for the calculation of the impact parameters of Dilute Pyroclastic Density Currents (DPDC) based on field data

    NASA Astrophysics Data System (ADS)

    Dioguardi, Fabio; Dellino, Pierfrancesco

    2014-05-01

    PYFLOW is a computer code designed for quantifying the hazard related to Dilute Pyroclastic Density Currents (DPDC). DPDCs are multiphase flows that form during explosive volcanic eruptions. They are the major source of hazard related to volcanic eruptions, as they exert a significant stress over buildings and transport significant amounts of volcanic ash, which is hot and unbreathable. The program calculates the DPDC's impact parameters (e.g. dynamic pressure and particle volumetric concentration) and is founded on the turbulent boundary layer theory adapted to a multiphase framework. Fluid-dynamic variables are searched with a probabilistic approach, meaning that for each variable the average, maximum and minimum solutions are calculated. From these values, PYFLOW creates probability functions that allow to calculate the parameter at a given percentile. The code is written in Fortran 90 and can be compiled and installed on Windows, Mac OS X, Linux operating systems (OS). A User's manual is provided, explaining the details of the theoretical background, the setup and running procedure and the input data. The model inputs are DPDC deposits data, e.g. particle grainsize, layer thickness, particles shape factor and density. PYFLOW reads input data from a specifically designed input file or from the user's direct typing by command lines. Guidelines for writing input data are also contained in the package. PYFLOW guides the user at each step of execution, asking for additional data and inputs. The program is a tool for DPDC hazard assessment and, as an example, an application to the DPDC deposits of the Agnano-Monte Spina eruption (4.1 ky BP) at Campi Flegrei (Italy) is presented.

  17. 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

  18. 'Bread Loaf' Mesa East of Phlegra Montes

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    An isolated mesa east of the Phlegra Montes in northeastern Elysium Planitia has a cracked surface that, combined with its overall shape, gives the appearance of a giant loaf of bread. Other mesas with similar surfaces are found in the area, suggesting that at one time these mesas were part of a continuous layer of material. It is likely that at that time, some process caused the graben-like cracks to form. Later erosion of the cracked layer left only the isolated mesas seen in the THEMIS image. One clue that supports this scenario is the presence of many filled and eroded craters throughout the scene but no fresh ones. One way to produce this landscape begins with an ancient and heavily cratered surface that subsequently is buried by some other material. If this overburden was stripped off relatively recently, not enough time would have passed to allow for a new population of fresh craters to be produced. The result would be a landscape with isolated mesas of younger material on top of an ancient, cratered surface.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor

  19. Coherent Scattering Imaging Monte Carlo Simulation

    NASA Astrophysics Data System (ADS)

    Hassan, Laila Abdulgalil Rafik

    Conventional mammography has poor contrast between healthy and cancerous tissues due to the small difference in attenuation properties. Coherent scatter potentially provides more information because interference of coherently scattered radiation depends on the average intermolecular spacing, and can be used to characterize tissue types. However, typical coherent scatter analysis techniques are not compatible with rapid low dose screening techniques. Coherent scatter slot scan imaging is a novel imaging technique which provides new information with higher contrast. In this work a simulation of coherent scatter was performed for slot scan imaging to assess its performance and provide system optimization. In coherent scatter imaging, the coherent scatter is exploited using a conventional slot scan mammography system with anti-scatter grids tilted at the characteristic angle of cancerous tissues. A Monte Carlo simulation was used to simulate the coherent scatter imaging. System optimization was performed across several parameters, including source voltage, tilt angle, grid distances, grid ratio, and shielding geometry. The contrast increased as the grid tilt angle increased beyond the characteristic angle for the modeled carcinoma. A grid tilt angle of 16 degrees yielded the highest contrast and signal to noise ratio (SNR). Also, contrast increased as the source voltage increased. Increasing grid ratio improved contrast at the expense of decreasing SNR. A grid ratio of 10:1 was sufficient to give a good contrast without reducing the intensity to a noise level. The optimal source to sample distance was determined to be such that the source should be located at the focal distance of the grid. A carcinoma lump of 0.5x0.5x0.5 cm3 in size was detectable which is reasonable considering the high noise due to the usage of relatively small number of incident photons for computational reasons. A further study is needed to study the effect of breast density and breast thickness

  20. Finding organic vapors - a Monte Carlo approach

    NASA Astrophysics Data System (ADS)

    Vuollekoski, Henri; Boy, Michael; Kerminen, Veli-Matti; Kulmala, Markku

    2010-05-01

    drawbacks in accuracy, the inability to find diurnal variation and the lack of size resolution. Here, we aim to shed some light onto the problem by applying an ad hoc Monte Carlo algorithm to a well established aerosol dynamical model, the University of Helsinki Multicomponent Aerosol model (UHMA). By performing a side-by-side comparison with measurement data within the algorithm, this approach has the significant advantage of decreasing the amount of manual labor. But more importantly, by basing the comparison on particle number size distribution data - a quantity that can be quite reliably measured - the accuracy of the results is good.

  1. Uncertainty Analyses for Localized Tallies in Monte Carlo Eigenvalue Calculations

    SciTech Connect

    Mervin, Brenden T.; Maldonado, G Ivan; Mosher, Scott W; Wagner, John C

    2011-01-01

    It is well known that statistical estimates obtained from Monte Carlo criticality simulations can be adversely affected by cycle-to-cycle correlations in the fission source. In addition there are several other more fundamental issues that may lead to errors in Monte Carlo results. These factors can have a significant impact on the calculated eigenvalue, localized tally means and their associated standard deviations. In fact, modern Monte Carlo computational tools may generate standard deviation estimates that are a factor of five or more lower than the true standard deviation for a particular tally due to the inter-cycle correlations in the fission source. The magnitude of this under-prediction can climb as high as one hundred when combined with an ill-converged fission source or poor sampling techniques. Since Monte Carlo methods are widely used in reactor analysis (as a benchmarking tool) and criticality safety applications, an in-depth understanding of the effects of these issues must be developed in order to support the practical use of Monte Carlo software packages. A rigorous statistical analysis of localized tally results in eigenvalue calculations is presented using the SCALE/KENO-VI and MCNP Monte Carlo codes. The purpose of this analysis is to investigate the under-prediction in the uncertainty and its sensitivity to problem characteristics and calculational parameters, and to provide a comparative study between the two codes with respect to this under-prediction. It is shown herein that adequate source convergence along with proper specification of Monte Carlo parameters can reduce the magnitude of under-prediction in the uncertainty to reasonable levels; below a factor of 2 when inter-cycle correlations in the fission source are not a significant factor. In addition, through the use of a modified sampling procedure, the effects of inter-cycle correlations on both the mean value and standard deviation estimates can be isolated.

  2. The Monte Carlo code MCPTV--Monte Carlo dose calculation in radiation therapy with carbon ions.

    PubMed

    Karg, Juergen; Speer, Stefan; Schmidt, Manfred; Mueller, Reinhold

    2010-07-07

    The Monte Carlo code MCPTV is presented. MCPTV is designed for dose calculation in treatment planning in radiation therapy with particles and especially carbon ions. MCPTV has a voxel-based concept and can perform a fast calculation of the dose distribution on patient CT data. Material and density information from CT are taken into account. Electromagnetic and nuclear interactions are implemented. Furthermore the algorithm gives information about the particle spectra and the energy deposition in each voxel. This can be used to calculate the relative biological effectiveness (RBE) for each voxel. Depth dose distributions are compared to experimental data giving good agreement. A clinical example is shown to demonstrate the capabilities of the MCPTV dose calculation.

  3. 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.

  4. Frequency domain optical tomography using a Monte Carlo perturbation method

    NASA Astrophysics Data System (ADS)

    Yamamoto, Toshihiro; Sakamoto, Hiroki

    2016-04-01

    A frequency domain Monte Carlo method is applied to near-infrared optical tomography, where an intensity-modulated light source with a given modulation frequency is used to reconstruct optical properties. The frequency domain reconstruction technique allows for better separation between the scattering and absorption properties of inclusions, even for ill-posed inverse problems, due to cross-talk between the scattering and absorption reconstructions. The frequency domain Monte Carlo calculation for light transport in an absorbing and scattering medium has thus far been analyzed mostly for the reconstruction of optical properties in simple layered tissues. This study applies a Monte Carlo calculation algorithm, which can handle complex-valued particle weights for solving a frequency domain transport equation, to optical tomography in two-dimensional heterogeneous tissues. The Jacobian matrix that is needed to reconstruct the optical properties is obtained by a first-order "differential operator" technique, which involves less variance than the conventional "correlated sampling" technique. The numerical examples in this paper indicate that the newly proposed Monte Carlo method provides reconstructed results for the scattering and absorption coefficients that compare favorably with the results obtained from conventional deterministic or Monte Carlo methods.

  5. Monte Carlo dose calculations in advanced radiotherapy

    NASA Astrophysics Data System (ADS)

    Bush, Karl Kenneth

    The remarkable accuracy of Monte Carlo (MC) dose calculation algorithms has led to the widely accepted view that these methods should and will play a central role in the radiotherapy treatment verification and planning of the future. The advantages of using MC clinically are particularly evident for radiation fields passing through inhomogeneities, such as lung and air cavities, and for small fields, including those used in today's advanced intensity modulated radiotherapy techniques. Many investigators have reported significant dosimetric differences between MC and conventional dose calculations in such complex situations, and have demonstrated experimentally the unmatched ability of MC calculations in modeling charged particle disequilibrium. The advantages of using MC dose calculations do come at a cost. The nature of MC dose calculations require a highly detailed, in-depth representation of the physical system (accelerator head geometry/composition, anatomical patient geometry/composition and particle interaction physics) to allow accurate modeling of external beam radiation therapy treatments. To perform such simulations is computationally demanding and has only recently become feasible within mainstream radiotherapy practices. In addition, the output of the accelerator head simulation can be highly sensitive to inaccuracies within a model that may not be known with sufficient detail. The goal of this dissertation is to both improve and advance the implementation of MC dose calculations in modern external beam radiotherapy. To begin, a novel method is proposed to fine-tune the output of an accelerator model to better represent the measured output. In this method an intensity distribution of the electron beam incident on the model is inferred by employing a simulated annealing algorithm. The method allows an investigation of arbitrary electron beam intensity distributions and is not restricted to the commonly assumed Gaussian intensity. In a second component of

  6. Monte Carlo studies of model Langmuir monolayers.

    PubMed

    Opps, S B; Yang, B; Gray, C G; Sullivan, D E

    2001-04-01

    This paper examines some of the basic properties of a model Langmuir monolayer, consisting of surfactant molecules deposited onto a water subphase. The surfactants are modeled as rigid rods composed of a head and tail segment of diameters sigma(hh) and sigma(tt), respectively. The tails consist of n(t) approximately 4-7 effective monomers representing methylene groups. These rigid rods interact via site-site Lennard-Jones potentials with different interaction parameters for the tail-tail, head-tail, and head-head interactions. In a previous paper, we studied the ground-state properties of this system using a Landau approach. In the present paper, Monte Carlo simulations were performed in the canonical ensemble to elucidate the finite-temperature behavior of this system. Simulation techniques, incorporating a system of dynamic filters, allow us to decrease CPU time with negligible statistical error. This paper focuses on several of the key parameters, such as density, head-tail diameter mismatch, and chain length, responsible for driving transitions from uniformly tilted to untilted phases and between different tilt-ordered phases. Upon varying the density of the system, with sigma(hh)=sigma(tt), we observe a transition from a tilted (NNN)-condensed phase to an untilted-liquid phase and, upon comparison with recent experiments with fatty acid-alcohol and fatty acid-ester mixtures [M. C. Shih, M. K. Durbin, A. Malik, P. Zschack, and P. Dutta, J. Chem. Phys. 101, 9132 (1994); E. Teer, C. M. Knobler, C. Lautz, S. Wurlitzer, J. Kildae, and T. M. Fischer, J. Chem. Phys. 106, 1913 (1997)], we identify this as the L'(2)/Ov-L1 phase boundary. By varying the head-tail diameter ratio, we observe a decrease in T(c) with increasing mismatch. However, as the chain length was increased we observed that the transition temperatures increased and differences in T(c) due to head-tail diameter mismatch were diminished. In most of the present research, the water was treated as a hard

  7. Monte Carlo studies of model Langmuir monolayers

    NASA Astrophysics Data System (ADS)

    Opps, S. B.; Yang, B.; Gray, C. G.; Sullivan, D. E.

    2001-04-01

    This paper examines some of the basic properties of a model Langmuir monolayer, consisting of surfactant molecules deposited onto a water subphase. The surfactants are modeled as rigid rods composed of a head and tail segment of diameters σhh and σtt, respectively. The tails consist of nt~4-7 effective monomers representing methylene groups. These rigid rods interact via site-site Lennard-Jones potentials with different interaction parameters for the tail-tail, head-tail, and head-head interactions. In a previous paper, we studied the ground-state properties of this system using a Landau approach. In the present paper, Monte Carlo simulations were performed in the canonical ensemble to elucidate the finite-temperature behavior of this system. Simulation techniques, incorporating a system of dynamic filters, allow us to decrease CPU time with negligible statistical error. This paper focuses on several of the key parameters, such as density, head-tail diameter mismatch, and chain length, responsible for driving transitions from uniformly tilted to untilted phases and between different tilt-ordered phases. Upon varying the density of the system, with σhh=σtt, we observe a transition from a tilted (NNN)-condensed phase to an untilted-liquid phase and, upon comparison with recent experiments with fatty acid-alcohol and fatty acid-ester mixtures [M. C. Shih, M. K. Durbin, A. Malik, P. Zschack, and P. Dutta, J. Chem. Phys. 101, 9132 (1994); E. Teer, C. M. Knobler, C. Lautz, S. Wurlitzer, J. Kildae, and T. M. Fischer, J. Chem. Phys. 106, 1913 (1997)], we identify this as the L'2/Ov-L1 phase boundary. By varying the head-tail diameter ratio, we observe a decrease in Tc with increasing mismatch. However, as the chain length was increased we observed that the transition temperatures increased and differences in Tc due to head-tail diameter mismatch were diminished. In most of the present research, the water was treated as a hard surface, whereby the surfactants are only

  8. A Monte Carlo investigation of the Hamiltonian mean field model

    NASA Astrophysics Data System (ADS)

    Pluchino, Alessandro; Andronico, Giuseppe; Rapisarda, Andrea

    2005-04-01

    We present a Monte Carlo numerical investigation of the Hamiltonian mean field (HMF) model. We begin by discussing canonical Metropolis Monte Carlo calculations, in order to check the caloric curve of the HMF model and study finite size effects. In the second part of the paper, we present numerical simulations obtained by means of a modified Monte Carlo procedure with the aim to test the stability of those states at minimum temperature and zero magnetization (homogeneous Quasi stationary states), which exist in the condensed phase of the model just below the critical point. For energy densities smaller than the limiting value U∼0.68, we find that these states are unstable confirming a recent result on the Vlasov stability analysis applied to the HMF model.

  9. Monte Carlo simulation in statistical physics: an introduction

    NASA Astrophysics Data System (ADS)

    Binder, K., Heermann, D. W.

    Monte Carlo Simulation in Statistical Physics deals with the computer simulation of many-body systems in condensed-matter physics and related fields of physics, chemistry and beyond, to traffic flows, stock market fluctuations, etc.). Using random numbers generated by a computer, probability distributions are calculated, allowing the estimation of the thermodynamic properties of various systems. This book describes the theoretical background to several variants of these Monte Carlo methods and gives a systematic presentation from which newcomers can learn to perform such simulations and to analyze their results. This fourth edition has been updated and a new chapter on Monte Carlo simulation of quantum-mechanical problems has been added. To help students in their work a special web server has been installed to host programs and discussion groups (http://wwwcp.tphys.uni-heidelberg.de). Prof. Binder was the winner of the Berni J. Alder CECAM Award for Computational Physics 2001.

  10. Monte Carlo simulation of laser attenuation characteristics in fog

    NASA Astrophysics Data System (ADS)

    Wang, Hong-Xia; Sun, Chao; Zhu, You-zhang; Sun, Hong-hui; Li, Pan-shi

    2011-06-01

    Based on the Mie scattering theory and the gamma size distribution model, the scattering extinction parameter of spherical fog-drop is calculated. For the transmission attenuation of the laser in the fog, a Monte Carlo simulation model is established, and the impact of attenuation ratio on visibility and field angle is computed and analysed using the program developed by MATLAB language. The results of the Monte Carlo method in this paper are compared with the results of single scattering method. The results show that the influence of multiple scattering need to be considered when the visibility is low, and single scattering calculations have larger errors. The phenomenon of multiple scattering can be interpreted more better when the Monte Carlo is used to calculate the attenuation ratio of the laser transmitting in the fog.

  11. Classical Perturbation Theory for Monte Carlo Studies of System Reliability

    SciTech Connect

    Lewins, Jeffrey D.

    2001-03-15

    A variational principle for a Markov system allows the derivation of perturbation theory for models of system reliability, with prospects of extension to generalized Markov processes of a wide nature. It is envisaged that Monte Carlo or stochastic simulation will supply the trial functions for such a treatment, which obviates the standard difficulties of direct analog Monte Carlo perturbation studies. The development is given in the specific mode for first- and second-order theory, using an example with known analytical solutions. The adjoint equation is identified with the importance function and a discussion given as to how both the forward and backward (adjoint) fields can be obtained from a single Monte Carlo study, with similar interpretations for the additional functions required by second-order theory. Generalized Markov models with age-dependence are identified as coming into the scope of this perturbation theory.

  12. BACKWARD AND FORWARD MONTE CARLO METHOD IN POLARIZED RADIATIVE TRANSFER

    SciTech Connect

    Yong, Huang; Guo-Dong, Shi; Ke-Yong, Zhu

    2016-03-20

    In general, the Stocks vector cannot be calculated in reverse in the vector radiative transfer. This paper presents a novel backward and forward Monte Carlo simulation strategy to study the vector radiative transfer in the participated medium. A backward Monte Carlo process is used to calculate the ray trajectory and the endpoint of the ray. The Stocks vector is carried out by a forward Monte Carlo process. A one-dimensional graded index semi-transparent medium was presented as the physical model and the thermal emission consideration of polarization was studied in the medium. The solution process to non-scattering, isotropic scattering, and the anisotropic scattering medium, respectively, is discussed. The influence of the optical thickness and albedo on the Stocks vector are studied. The results show that the U, V-components of the apparent Stocks vector are very small, but the Q-component of the apparent Stocks vector is relatively larger, which cannot be ignored.

  13. 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.

  14. Monte Carlo tests of the ELIPGRID-PC algorithm

    SciTech Connect

    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 rectangular 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.

  15. SPQR: a Monte Carlo reactor kinetics code. [LMFBR

    SciTech Connect

    Cramer, S.N.; Dodds, H.L.

    1980-02-01

    The SPQR Monte Carlo code has been developed to analyze fast reactor core accident problems where conventional methods are considered inadequate. The code is based on the adiabatic approximation of the quasi-static method. This initial version contains no automatic material motion or feedback. An existing Monte Carlo code is used to calculate the shape functions and the integral quantities needed in the kinetics module. Several sample problems have been devised and analyzed. Due to the large statistical uncertainty associated with the calculation of reactivity in accident simulations, the results, especially at later times, differ greatly from deterministic methods. It was also found that in large uncoupled systems, the Monte Carlo method has difficulty in handling asymmetric perturbations.

  16. Photon beam description in PEREGRINE for Monte Carlo dose calculations

    SciTech Connect

    Cox, L. J., LLNL

    1997-03-04

    Goal of PEREGRINE is to provide capability for accurate, fast Monte Carlo calculation of radiation therapy dose distributions for routine clinical use and for research into efficacy of improved dose calculation. An accurate, efficient method of describing and sampling radiation sources is needed, and a simple, flexible solution is provided. The teletherapy source package for PEREGRINE, coupled with state-of-the-art Monte Carlo simulations of treatment heads, makes it possible to describe any teletherapy photon beam to the precision needed for highly accurate Monte Carlo dose calculations in complex clinical configurations that use standard patient modifiers such as collimator jaws, wedges, blocks, and/or multi-leaf collimators. Generic beam descriptions for a class of treatment machines can readily be adjusted to yield dose calculation to match specific clinical sites.

  17. Implementation of Monte Carlo Simulations for the Gamma Knife System

    NASA Astrophysics Data System (ADS)

    Xiong, W.; Huang, D.; Lee, L.; Feng, J.; Morris, K.; Calugaru, E.; Burman, C.; Li, J.; Ma, C.-M.

    2007-06-01

    Currently the Gamma Knife system is accompanied with a treatment planning system, Leksell GammaPlan (LGP) which is a standard, computer-based treatment planning system for Gamma Knife radiosurgery. In LGP, the dose calculation algorithm does not consider the scatter dose contributions and the inhomogeneity effect due to the skull and air cavities. To improve the dose calculation accuracy, Monte Carlo simulations have been implemented for the Gamma Knife planning system. In this work, the 201 Cobalt-60 sources in the Gamma Knife unit are considered to have the same activity. Each Cobalt-60 source is contained in a cylindric stainless steel capsule. The particle phase space information is stored in four beam data files, which are collected in the inner sides of the 4 treatment helmets, after the Cobalt beam passes through the stationary and helmet collimators. Patient geometries are rebuilt from patient CT data. Twenty two Patients are included in the Monte Carlo simulation for this study. The dose is calculated using Monte Carlo in both homogenous and inhomogeneous geometries with identical beam parameters. To investigate the attenuation effect of the skull bone the dose in a 16cm diameter spherical QA phantom is measured with and without a 1.5mm Lead-covering and also simulated using Monte Carlo. The dose ratios with and without the 1.5mm Lead-covering are 89.8% based on measurements and 89.2% according to Monte Carlo for a 18mm-collimator Helmet. For patient geometries, the Monte Carlo results show that although the relative isodose lines remain almost the same with and without inhomogeneity corrections, the difference in the absolute dose is clinically significant. The average inhomogeneity correction is (3.9 ± 0.90) % for the 22 patients investigated. These results suggest that the inhomogeneity effect should be considered in the dose calculation for Gamma Knife treatment planning.

  18. 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

  19. Parallel Monte Carlo Simulation for control system design

    NASA Technical Reports Server (NTRS)

    Schubert, Wolfgang M.

    1995-01-01

    The research during the 1993/94 academic year addressed the design of parallel algorithms for stochastic robustness synthesis (SRS). SRS uses Monte Carlo simulation to compute probabilities of system instability and other design-metric violations. The probabilities form a cost function which is used by a genetic algorithm (GA). The GA searches for the stochastic optimal controller. The existing sequential algorithm was analyzed and modified to execute in a distributed environment. For this, parallel approaches to Monte Carlo simulation and genetic algorithms were investigated. Initial empirical results are available for the KSR1.

  20. A review of best practices for Monte Carlo criticality calculations

    SciTech Connect

    Brown, Forrest B

    2009-01-01

    Monte Carlo methods have been used to compute k{sub eff} and the fundamental mode eigenfunction of critical systems since the 1950s. While such calculations have become routine using standard codes such as MCNP and SCALE/KENO, there still remain 3 concerns that must be addressed to perform calculations correctly: convergence of k{sub eff} and the fission distribution, bias in k{sub eff} and tally results, and bias in statistics on tally results. This paper provides a review of the fundamental problems inherent in Monte Carlo criticality calculations. To provide guidance to practitioners, suggested best practices for avoiding these problems are discussed and illustrated by examples.

  1. Monte Carlo Simulations of Phosphate Polyhedron Connectivity in Glasses

    SciTech Connect

    ALAM,TODD M.

    1999-12-21

    Monte Carlo simulations of phosphate tetrahedron connectivity distributions in alkali and alkaline earth phosphate glasses are reported. By utilizing a discrete bond model, the distribution of next-nearest neighbor connectivities between phosphate polyhedron for random, alternating and clustering bonding scenarios was evaluated as a function of the relative bond energy difference. The simulated distributions are compared to experimentally observed connectivities reported for solid-state two-dimensional exchange and double-quantum NMR experiments of phosphate glasses. These Monte Carlo simulations demonstrate that the polyhedron connectivity is best described by a random distribution in lithium phosphate and calcium phosphate glasses.

  2. 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.

  3. Research in the Mont Terri Rock laboratory: Quo vadis?

    NASA Astrophysics Data System (ADS)

    Bossart, Paul; Thury, Marc

    During the past 10 years, the 12 Mont Terri partner organisations ANDRA, BGR, CRIEPI, ENRESA, FOWG (now SWISSTOPO), GRS, HSK, IRSN, JAEA, NAGRA, OBAYASHI and SCK-CEN have jointly carried out and financed a research programme in the Mont Terri Rock Laboratory. An important strategic question for the Mont Terri project is what type of new experiments should be carried out in the future. This question has been discussed among partner delegates, authorities, scientists, principal investigators and experiment delegates. All experiments at Mont Terri - past, ongoing and future - can be assigned to the following three categories: (1) process and mechanism understanding in undisturbed argillaceous formations, (2) experiments related to excavation- and repository-induced perturbations and (3) experiments related to repository performance during the operational and post-closure phases. In each of these three areas, there are still open questions and hence potential experiments to be carried out in the future. A selection of key issues and questions which have not, or have only partly been addressed so far and in which the project partners, but also the safety authorities and other research organisations may be interested, are presented in the following. The Mont Terri Rock Laboratory is positioned as a generic rock laboratory, where research and development is key: mainly developing methods for site characterisation of argillaceous formations, process understanding and demonstration of safety. Due to geological constraints, there will never be a site specific rock laboratory at Mont Terri. The added value for the 12 partners in terms of future experiments is threefold: (1) the Mont Terri project provides an international scientific platform of high reputation for research on radioactive waste disposal (= state-of-the-art research in argillaceous materials); (2) errors are explicitly allowed (= rock laboratory as a “playground” where experience is often gained through

  4. A Monte Carlo method for combined segregation and linkage analysis

    SciTech Connect

    Guo, S.W. ); Thompson, E.A. )

    1992-11-01

    The authors introduce a Monte Carlo approach to combined segregation and linkage analysis of a quantitative trait observed in an extended pedigree. In conjunction with the Monte Carlo method of likelihood-ratio evaluation proposed by Thompson and Guo, the method provides for estimation and hypothesis testing. The greatest attraction of this approach is its ability to handle complex genetic models and large pedigrees. Two examples illustrate the practicality of the method. One is of simulated data on a large pedigree; the other is a reanalysis of published data previously analyzed by other methods. 40 refs, 5 figs., 5 tabs.

  5. Markov chain Monte Carlo linkage analysis of complex quantitative phenotypes.

    PubMed

    Hinrichs, A; Reich, T

    2001-01-01

    We report a Markov chain Monte Carlo analysis of the five simulated quantitative traits in Genetic Analysis Workshop 12 using the Loki software. Our objectives were to determine the efficacy of the Markov chain Monte Carlo method and to test a new scoring technique. Our initial blind analysis, on replicate 42 (the "best replicate") successfully detected four out of the five disease loci and found no false positives. A power analysis shows that the software could usually detect 4 of the 10 trait/gene combinations at an empirical point-wise p-value of 1.5 x 10(-4).

  6. Novel Quantum Monte Carlo Approaches for Quantum Liquids

    NASA Astrophysics Data System (ADS)

    Rubenstein, Brenda M.

    Quantum Monte Carlo methods are a powerful suite of techniques for solving the quantum many-body problem. By using random numbers to stochastically sample quantum properties, QMC methods are capable of studying low-temperature quantum systems well beyond the reach of conventional deterministic techniques. QMC techniques have likewise been indispensible tools for augmenting our current knowledge of superfluidity and superconductivity. In this thesis, I present two new quantum Monte Carlo techniques, the Monte Carlo Power Method and Bose-Fermi Auxiliary-Field Quantum Monte Carlo, and apply previously developed Path Integral Monte Carlo methods to explore two new phases of quantum hard spheres and hydrogen. I lay the foundation for a subsequent description of my research by first reviewing the physics of quantum liquids in Chapter One and the mathematics behind Quantum Monte Carlo algorithms in Chapter Two. I then discuss the Monte Carlo Power Method, a stochastic way of computing the first several extremal eigenvalues of a matrix too memory-intensive to be stored and therefore diagonalized. As an illustration of the technique, I demonstrate how it can be used to determine the second eigenvalues of the transition matrices of several popular Monte Carlo algorithms. This information may be used to quantify how rapidly a Monte Carlo algorithm is converging to the equilibrium probability distribution it is sampling. I next present the Bose-Fermi Auxiliary-Field Quantum Monte Carlo algorithm. This algorithm generalizes the well-known Auxiliary-Field Quantum Monte Carlo algorithm for fermions to bosons and Bose-Fermi mixtures. Despite some shortcomings, the Bose-Fermi Auxiliary-Field Quantum Monte Carlo algorithm represents the first exact technique capable of studying Bose-Fermi mixtures of any size in any dimension. In Chapter Six, I describe a new Constant Stress Path Integral Monte Carlo algorithm for the study of quantum mechanical systems under high pressures. While

  7. Complexity of Monte Carlo and deterministic dose-calculation methods.

    PubMed

    Börgers, C

    1998-03-01

    Grid-based deterministic dose-calculation methods for radiotherapy planning require the use of six-dimensional phase space grids. Because of the large number of phase space dimensions, a growing number of medical physicists appear to believe that grid-based deterministic dose-calculation methods are not competitive with Monte Carlo methods. We argue that this conclusion may be premature. Our results do suggest, however, that finite difference or finite element schemes with orders of accuracy greater than one will probably be needed if such methods are to compete well with Monte Carlo methods for dose calculations.

  8. 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

  9. Parton distribution functions in Monte Carlo factorisation scheme

    NASA Astrophysics Data System (ADS)

    Jadach, S.; Płaczek, W.; Sapeta, S.; Siódmok, A.; Skrzypek, M.

    2016-12-01

    A next step in development of the KrkNLO method of including complete NLO QCD corrections to hard processes in a LO parton-shower Monte Carlo is presented. It consists of a generalisation of the method, previously used for the Drell-Yan process, to Higgs-boson production. This extension is accompanied with the complete description of parton distribution functions in a dedicated, Monte Carlo factorisation scheme, applicable to any process of production of one or more colour-neutral particles in hadron-hadron collisions.

  10. Towards Fast, Scalable Hard Particle Monte Carlo Simulations on GPUs

    NASA Astrophysics Data System (ADS)

    Anderson, Joshua A.; Irrgang, M. Eric; Glaser, Jens; Harper, Eric S.; Engel, Michael; Glotzer, Sharon C.

    2014-03-01

    Parallel algorithms for Monte Carlo simulations of thermodynamic ensembles of particles have received little attention because of the inherent serial nature of the statistical sampling. We discuss the implementation of Monte Carlo for arbitrary hard shapes in HOOMD-blue, a GPU-accelerated particle simulation tool, to enable million particle simulations in a field where thousands is the norm. In this talk, we discuss our progress on basic parallel algorithms, optimizations that maximize GPU performance, and communication patterns for scaling to multiple GPUs. Research applications include colloidal assembly and other uses in materials design, biological aggregation, and operations research.

  11. Kinetic Monte Carlo method applied to nucleic acid hairpin folding.

    PubMed

    Sauerwine, Ben; Widom, Michael

    2011-12-01

    Kinetic Monte Carlo on coarse-grained systems, such as nucleic acid secondary structure, is advantageous for being able to access behavior at long time scales, even minutes or hours. Transition rates between coarse-grained states depend upon intermediate barriers, which are not directly simulated. We propose an Arrhenius rate model and an intermediate energy model that incorporates the effects of the barrier between simulated states without enlarging the state space itself. Applying our Arrhenius rate model to DNA hairpin folding, we demonstrate improved agreement with experiment compared to the usual kinetic Monte Carlo model. Further improvement results from including rigidity of single-stranded stacking.

  12. Monte Carlo Analysis of Quantum Transport and Fluctuations in Semiconductors.

    DTIC Science & Technology

    1986-02-18

    methods to quantum transport within the Liouville formulation. The second part concerns with fluctuations of carrier velocities and energies both in...interactions) on the transport properties. Keywords: Monte Carlo; Charge Transport; Quantum Transport ; Fluctuations; Semiconductor Physics; Master Equation...The present report contains technical matter related to the research performed on two different subjects. The first part concerns with quantum

  13. Monte Carlo simulation by computer for life-cycle costing

    NASA Technical Reports Server (NTRS)

    Gralow, F. H.; Larson, W. J.

    1969-01-01

    Prediction of behavior and support requirements during the entire life cycle of a system enables accurate cost estimates by using the Monte Carlo simulation by computer. The system reduces the ultimate cost to the procuring agency because it takes into consideration the costs of initial procurement, operation, and maintenance.

  14. MODELING LEACHING OF VIRUSES BY THE MONTE CARLO METHOD

    EPA Science Inventory

    A predictive screening model was developed for fate and transport
    of viruses in the unsaturated zone. A database of input parameters
    allowed Monte Carlo analysis with the model. The resulting kernel
    densities of predicted attenuation during percolation indicated very ...

  15. The Metropolis Monte Carlo Method in Statistical Physics

    NASA Astrophysics Data System (ADS)

    Landau, David P.

    2003-11-01

    A brief overview is given of some of the advances in statistical physics that have been made using the Metropolis Monte Carlo method. By complementing theory and experiment, these have increased our understanding of phase transitions and other phenomena in condensed matter systems. A brief description of a new method, commonly known as "Wang-Landau sampling," will also be presented.

  16. Quantum Monte Carlo simulation of topological phase transitions

    NASA Astrophysics Data System (ADS)

    Yamamoto, Arata; Kimura, Taro

    2016-12-01

    We study the electron-electron interaction effects on topological phase transitions by the ab initio quantum Monte Carlo simulation. We analyze two-dimensional class A topological insulators and three-dimensional Weyl semimetals with the long-range Coulomb interaction. The direct computation of the Chern number shows the electron-electron interaction modifies or extinguishes topological phase transitions.

  17. The Use of Monte Carlo Techniques to Teach Probability.

    ERIC Educational Resources Information Center

    Newell, G. J.; MacFarlane, J. D.

    1985-01-01

    Presents sports-oriented examples (cricket and football) in which Monte Carlo methods are used on microcomputers to teach probability concepts. Both examples include computer programs (with listings) which utilize the microcomputer's random number generator. Instructional strategies, with further challenges to help students understand the role of…

  18. Error estimations and their biases in Monte Carlo eigenvalue calculations

    SciTech Connect

    Ueki, Taro; Mori, Takamasa; Nakagawa, Masayuki

    1997-01-01

    In the Monte Carlo eigenvalue calculation of neutron transport, the eigenvalue is calculated as the average of multiplication factors from cycles, which are called the cycle k{sub eff}`s. Biases in the estimators of the variance and intercycle covariances in Monte Carlo eigenvalue calculations are analyzed. The relations among the real and apparent values of variances and intercycle covariances are derived, where real refers to a true value that is calculated from independently repeated Monte Carlo runs and apparent refers to the expected value of estimates from a single Monte Carlo run. Next, iterative methods based on the foregoing relations are proposed to estimate the standard deviation of the eigenvalue. The methods work well for the cases in which the ratios of the real to apparent values of variances are between 1.4 and 3.1. Even in the case where the foregoing ratio is >5, >70% of the standard deviation estimates fall within 40% from the true value.

  19. Diffuse photon density wave measurements and Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Kuzmin, Vladimir L.; Neidrauer, Michael T.; Diaz, David; Zubkov, Leonid A.

    2015-10-01

    Diffuse photon density wave (DPDW) methodology is widely used in a number of biomedical applications. Here, we present results of Monte Carlo simulations that employ an effective numerical procedure based upon a description of radiative transfer in terms of the Bethe-Salpeter equation. A multifrequency noncontact DPDW system was used to measure aqueous solutions of intralipid at a wide range of source-detector separation distances, at which the diffusion approximation of the radiative transfer equation is generally considered to be invalid. We find that the signal-noise ratio is larger for the considered algorithm in comparison with the conventional Monte Carlo approach. Experimental data are compared to the Monte Carlo simulations using several values of scattering anisotropy and to the diffusion approximation. Both the Monte Carlo simulations and diffusion approximation were in very good agreement with the experimental data for a wide range of source-detector separations. In addition, measurements with different wavelengths were performed to estimate the size and scattering anisotropy of scatterers.

  20. Calculating coherent pair production with Monte Carlo methods

    SciTech Connect

    Bottcher, C.; Strayer, M.R.

    1989-01-01

    We discuss calculations of the coherent electromagnetic pair production in ultra-relativistic hadron collisions. This type of production, in lowest order, is obtained from three diagrams which contain two virtual photons. We discuss simple Monte Carlo methods for evaluating these classes of diagrams without recourse to involved algebraic reduction schemes. 19 refs., 11 figs.