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Sample records for 1-g model tests

  1. Correlation of AH-1G airframe test data with a NASTRAN mathematical model

    NASA Technical Reports Server (NTRS)

    Cronkhite, J. D.; Berry, V. L.

    1976-01-01

    Test data was provided for evaluating a mathematical vibration model of the Bell AH-1G helicopter airframe. The math model was developed and analyzed using the NASTRAN structural analysis computer program. Data from static and dynamic tests were used for comparison with the math model. Static tests of the fuselage and tailboom were conducted to verify the stiffness representation of the NASTRAN model. Dynamic test data were obtained from shake tests of the airframe and were used to evaluate the NASTRAN model for representing the low frequency (below 30 Hz) vibration response of the airframe.

  2. Summary of the modeling and test correlations of a NASTRAN finite element vibrations model for the AH-1G helicopter, task 1

    NASA Technical Reports Server (NTRS)

    Cronkhite, J. D.; Berry, V. L.; Dompka, R. V.

    1987-01-01

    The AH-1G NASTRAN finite element model (FEM) is described and the correlations with measured data that were conducted to verify the model are summarized. Comparisons of the AH-1G NASTRAN FEM calculations with measured data include the following: (1) fuselage and tailboom static load deflection (stiffness) testing, (2) airframe ground vibration testing (0-30 H<), (3) airframe flight vibration testing (main rotor, 2,4, and 6/rev), and (4) tailboom effective skin static testing. A description of the modeling rationale and techniques used to develop the NASTRAN FEM is presented in conjunction with all previous correlation work. In general, the correlations show good agreement between analysis and test in stiffness and vibration response through 15 to 20 Hz. For higher frequencies (equal to or greater than 4/rev (21.6 Hz)), the vibration responses generally did not agree well. Also, the lateral (2/rev (10.8 Hz)) flight vibration responses were much lower in the FEM than test, indicating that there is a significant excitation source other than at the main rotor hub that is affecting the lateral vibrations, such as downwash impingement on the vertical tail.

  3. Investigation of difficult component effects on finite element model vibration prediction for the Bell AH-1G helicopter. Volume 1: Ground vibration test results

    NASA Technical Reports Server (NTRS)

    Dompka, R. V.

    1989-01-01

    Under the NASA-sponsored Design Analysis Methods for VIBrationS (DAMVIBS) program, a series of ground vibration tests and NASTRAN finite element model (FEM) correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Previous correlations of the AH-1G showed good agreement between NASTRAN and tests through 15 to 20 Hz, but poor agreement in the higher frequency range of 20 to 30 Hz. Thus, this effort emphasized the higher frequency airframe vibration response correlations and identified areas that need further R and T work. To conduct the investigations, selected difficult components (main rotor pylon, secondary structure, nonstructural doors/panels, landing gear, engine, fuel, etc.) were systematically removed to quantify their effects on overall vibratory response of the airframe. The entire effort was planned and documented, and the results reviewed by NASA and industry experts in order to ensure scientific control of the testing, analysis, and correlation exercise. In particular, secondary structure and damping had significant effects on the frequency response of the airframe above 15 Hz. Also, the nonlinear effects of thrust stiffening and elastomer mounts were significant on the low frequency pylon modes below main rotor 1p (5.4 Hz). The results of the ground vibration testing are presented.

  4. Still Just 1 "g": Consistent Results from Five Test Batteries

    ERIC Educational Resources Information Center

    Johnson, Wendy; te Nijenhuis, Jan; Bouchard, Thomas J., Jr.

    2008-01-01

    In a recent paper, Johnson, Bouchard, Krueger, McGue, and Gottesman (2004) addressed a long-standing debate in psychology by demonstrating that the g factors derived from three test batteries administered to a single group of individuals were completely correlated. This finding provided evidence for the existence of a unitary higher-level general…

  5. Some Important Aspects of Physical Modelling of Liquefaction in 1-g Shaking Table

    SciTech Connect

    Alam, Md. Jahangir; Towhata, Ikuo

    2008-07-08

    Physical modeling of liquefaction in 1-g shaking table and dynamic centrifuge test become very popular to simulate the ground behavior during earthquake motion. 1-g shaking table tests require scaled down model ground which can be prepared in three methods; water sedimentation, moist tamping and dry deposition method. Moist tamping and dry deposition method need saturation of model ground which is expensive and very difficult to achieve. Some model tests were performed in 1-g shaking table to see the influence of preparation method of model ground. Wet tamping and water sedimentation method of ground preparation were compared in these tests. Behavior of level ground and slope were also examined. Slope and level ground model test increased the understanding of excess pore pressure generation in both cases. Wet tamping method has a possibility of not being fully saturated. Pore pressure transducers should be fixed vertically so that it can not settle down during shaking but can move with ground. There was insignificant difference in acceleration and excess pore pressure responses between wet tamping and water sedimentation method in case of level ground. Spiky accelerations were prominent in slope prepared by water sedimentation method. Spiky accelerations were the result of lateral displacement induced dilatancy of soil.

  6. Amino acids as biomarkers in the SOD1(G93A) mouse model of ALS.

    PubMed

    Bame, Monica; Grier, Robert E; Needleman, Richard; Brusilow, William S A

    2014-01-01

    The development of therapies for Amyotrophic Lateral Sclerosis (ALS) has been hindered by the lack of biomarkers for both identifying early disease and for monitoring the effectiveness of drugs. The identification of ALS biomarkers in presymptomatic individuals might also provide clues to the earliest biochemical correlates of the disease. Previous attempts to use plasma metabolites as biomarkers have led to contradictory results, presumably because of heterogeneity in both the underlying genetics and the disease stage in the clinical population. To eliminate these two sources of heterogeneity we have characterized plasma amino acids and other metabolites in the SOD1(G93A) transgenic mouse model for ALS. Presymptomatic SOD1(G93A) mice have significant differences in concentrations of several plasma metabolites compared to wild type animals, most notably in the concentrations of aspartate, cystine/cysteine, and phosphoethanolamine, and in changes indicative of methylation defects. There are significant changes in amino acid compositions between 50 and 70days of age in both the SOD1(G93A) and wild type mice, and several of the age-related and disease-related differences in metabolite concentration were also gender-specific. Many of the SOD1(G93A)-related differences could be altered by treatment of mice with methionine sulfoximine, which extends the lifespan of this mouse, inhibits glutamine synthetase, and modifies brain methylation reactions. These studies show that assaying plasma metabolites can effectively distinguish transgenic mice from wild type, suggesting that one or more plasma metabolites might be useful biomarkers for the disease in humans, especially if genetic and longitudinal analysis is used to reduce population heterogeneity. PMID:24129262

  7. TDP-43 modification in the hSOD1(G93A) amyotrophic lateral sclerosis mouse model.

    PubMed

    Cai, MuDan; Lee, Kang-Woo; Choi, Sun-Mi; Yang, Eun Jin

    2015-03-01

    Amyotrophic lateral sclerosis (ALS) is an adult onset disease that produces gradual motor neuron cell death in the spinal cord (SP). Recently, transactive response DNA-binding protein 43 kDa (TDP-43), a critical component of insoluble ubiquitinated inclusions, has received attention in the treatment of neurodegenerative disorders, including frontotemporal lobar degeneration (FTLD) and ALS. TDP-43 modifications, including hyperphosphorylation, truncation, and ubiquitination, have been reported in the pathogenesis of neurodegenerative diseases (NDs). However, the pathogenic mechanism of TDP-43 in ALS is unclear. To determine the association between TDP-43 and neurotoxicity in an ALS model, we characterized TDP-43 expression in hSOD1(G93A) transgenic mice (Tg) as an ALS animal model. TDP-43 was expressed by astrocytes and microglial cells in the SP of hSOD1(G93A) transgenic mice. In addition, the expression of phosphorylated and truncated TDP-43 increased in the SP of ALS mice compared with age-matched non-Tg. Furthermore, the serum iron concentration and expression of transferrin, a homeostasis-related iron protein, in the SP were increased relative to non-Tg. The protein expression level of HO-1 related to oxidative stress was increased in the SP of hSOD1(G93A) Tg relative to non-Tg. We show that an increase of TDP-43 modification, including phosphorylation or truncation, associates with dysfunctional iron homeostasis and an increase in oxidative stress in the SP of symptomatic hSOD1(G93A) Tg. These findings suggest that modified TDP-43 may be involved in motor neuron death in the SP of a SOD1(G93A)-expressing familial ALS (fALS) animal model. PMID:25213598

  8. Resveratrol Ameliorates Motor Neuron Degeneration and Improves Survival in SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis

    PubMed Central

    Song, Lin; Zhang, Xiaojie; Li, Jia; Le, Weidong

    2014-01-01

    Resveratrol has recently been used as a supplemental treatment for several neurological and nonneurological diseases. It is not known whether resveratrol has neuroprotective effect on amyotrophic lateral sclerosis (ALS). To assess the effect of resveratrol on the disease, we tested this agent on an ALS model of SOD1G93A transgenic mouse. Rotarod measurement was performed to measure the motor function of the ALS mice. Nissl staining and SMI-32 immunofluorescent staining were used to determine motor neurons survival in the spinal cord of the ALS mice. Hematoxylin-eosin (H&E), succinic dehydrogenase (SDH), and cytochrome oxidase (COX) staining were applied to pathologically analyze the skeletal muscles of the ALS mice. We found that resveratrol treatment significantly delayed the disease onset and prolonged the lifespan of the ALS mice. Furthermore, resveratrol treatment attenuated motor neuron loss, relieved muscle atrophy, and improved mitochondrial function of muscle fibers in the ALS mice. In addition, we demonstrated that resveratrol exerted these neuroprotective effects mainly through increasing the expression of Sirt1, consequently suppressing oxidative stress and downregulating p53 and its related apoptotic pathway. Collectively, our findings suggest that resveratrol might provide a promising therapeutic intervention for ALS. PMID:25057490

  9. Molecular Chaperone Mediated Late-Stage Neuroprotection in the SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis

    PubMed Central

    Gray, Anna L.; Dick, James R.; Kanuga, Naheed; Kalmar, Bernadett; Greensmith, Linda; Cheetham, Michael E.

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by the selective loss of motor neurons in the spinal cord, brain stem, and motor cortex. Mutations in superoxide dismutase (SOD1) are associated with familial ALS and lead to SOD1 protein misfolding and aggregation. Here we show that the molecular chaperone, HSJ1 (DNAJB2), mutations in which cause distal hereditary motor neuropathy, can reduce mutant SOD1 aggregation and improve motor neuron survival in mutant SOD1 models of ALS. Overexpression of human HSJ1a (hHSJ1a) in vivo in motor neurons of SOD1G93A transgenic mice ameliorated disease. In particular, there was a significant improvement in muscle force, increased motor unit number and enhanced motor neuron survival. hHSJ1a was present in a complex with SOD1G93A and led to reduced SOD1 aggregation at late stages of disease progression. We also observed altered ubiquitin immunoreactivity in the double transgenic animals, suggesting that ubiquitin modification might be important for the observed improvements. In a cell model of SOD1G93A aggregation, HSJ1a preferentially bound to mutant SOD1, enhanced SOD1 ubiquitylation and reduced SOD1 aggregation in a J-domain and ubiquitin interaction motif (UIM) dependent manner. Collectively, the data suggest that HSJ1a acts on mutant SOD1 through a combination of chaperone, co-chaperone and pro-ubiquitylation activity. These results show that targeting SOD1 protein misfolding and aggregation in vivo can be neuroprotective and suggest that manipulation of DnaJ molecular chaperones might be useful in the treatment of ALS. PMID:24023695

  10. Tempol moderately extends survival in a hSOD1(G93A) ALS rat model by inhibiting neuronal cell loss, oxidative damage and levels of non-native hSOD1(G93A) forms.

    PubMed

    Linares, Edlaine; Seixas, Luciana V; dos Prazeres, Janaina N; Ladd, Fernando V L; Ladd, Aliny A B L; Coppi, Antonio A; Augusto, Ohara

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive dysfunction and death of motor neurons by mechanisms that remain unclear. Evidence indicates that oxidative mechanisms contribute to ALS pathology, but classical antioxidants have not performed well in clinical trials. Cyclic nitroxides are an alternative worth exploring because they are multifunctional antioxidants that display low toxicity in vivo. Here, we examine the effects of the cyclic nitroxide tempol (4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl) on ALS onset and progression in transgenic female rats over-expressing the mutant hSOD1(G93A) . Starting at 7 weeks of age, a high dose of tempol (155 mg/day/rat) in the rat´s drinking water had marginal effects on the disease onset but decelerated disease progression and extended survival by 9 days. In addition, tempol protected spinal cord tissues as monitored by the number of neuronal cells, and the reducing capability and levels of carbonylated proteins and non-native hSOD1 forms in spinal cord homogenates. Intraperitoneal tempol (26 mg/rat, 3 times/week) extended survival by 17 days. This group of rats, however, diverted to a decelerated disease progression. Therefore, it was inconclusive whether the higher protective effect of the lower i.p. dose was due to higher tempol bioavailability, decelerated disease development or both. Collectively, the results show that tempol moderately extends the survival of ALS rats while protecting their cellular and molecular structures against damage. Thus, the results provide proof that cyclic nitroxides are alternatives worth to be further tested in animal models of ALS. PMID:23405225

  11. Tempol Moderately Extends Survival in a hSOD1G93A ALS Rat Model by Inhibiting Neuronal Cell Loss, Oxidative Damage and Levels of Non-Native hSOD1G93A Forms

    PubMed Central

    Linares, Edlaine; Seixas, Luciana V.; dos Prazeres, Janaina N.; Ladd, Fernando V. L.; Ladd, Aliny A. B. L.; Coppi, Antonio A.; Augusto, Ohara

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive dysfunction and death of motor neurons by mechanisms that remain unclear. Evidence indicates that oxidative mechanisms contribute to ALS pathology, but classical antioxidants have not performed well in clinical trials. Cyclic nitroxides are an alternative worth exploring because they are multifunctional antioxidants that display low toxicity in vivo. Here, we examine the effects of the cyclic nitroxide tempol (4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl) on ALS onset and progression in transgenic female rats over-expressing the mutant hSOD1G93A . Starting at 7 weeks of age, a high dose of tempol (155 mg/day/rat) in the rat´s drinking water had marginal effects on the disease onset but decelerated disease progression and extended survival by 9 days. In addition, tempol protected spinal cord tissues as monitored by the number of neuronal cells, and the reducing capability and levels of carbonylated proteins and non-native hSOD1 forms in spinal cord homogenates. Intraperitoneal tempol (26 mg/rat, 3 times/week) extended survival by 17 days. This group of rats, however, diverted to a decelerated disease progression. Therefore, it was inconclusive whether the higher protective effect of the lower i.p. dose was due to higher tempol bioavailability, decelerated disease development or both. Collectively, the results show that tempol moderately extends the survival of ALS rats while protecting their cellular and molecular structures against damage. Thus, the results provide proof that cyclic nitroxides are alternatives worth to be further tested in animal models of ALS. PMID:23405225

  12. ALS mouse model SOD1G93A displays early pathology of sensory small fibers associated to accumulation of a neurotoxic splice variant of peripherin.

    PubMed

    Sassone, Jenny; Taiana, Michela; Lombardi, Raffaella; Porretta-Serapiglia, Carla; Freschi, Mattia; Bonanno, Silvia; Marcuzzo, Stefania; Caravello, Francesca; Bendotti, Caterina; Lauria, Giuseppe

    2016-04-15

    Growing evidence suggests that amyotrophic lateral sclerosis (ALS) is a multisystem neurodegenerative disease that primarily affects motor neurons and, though less evidently, other neuronal systems. About 75% of sporadic and familial ALS patients show a subclinical degeneration of small-diameter fibers, as measured by loss of intraepidermal nerve fibers (IENFs), but the underlying biological causes are unknown. Small-diameter fibers are derived from small-diameter sensory neurons, located in dorsal root ganglia (DRG), whose biochemical hallmark is the expression of type III intermediate filament peripherin. We tested here the hypothesis that small-diameter DRG neurons of ALS mouse model SOD1(G93A)suffer from axonal stress and investigated the underlying molecular mechanism. We found that SOD1(G93A)mice display small fiber pathology, as measured by IENF loss, which precedes the onset of the disease. In vitro small-diameter DRG neurons of SOD1(G93A)mice show axonal stress features and accumulation of a peripherin splice variant, named peripherin56, which causes axonal stress through disassembling light and medium neurofilament subunits (NFL and NFM, respectively). Our findings first demonstrate that small-diameter DRG neurons of the ALS mouse model SOD1(G93A)display axonal stress in vitro and in vivo, thus sustaining the hypothesis that the effects of ALS disease spread beyond motor neurons. These results suggest a molecular mechanism for the small fiber pathology found in ALS patients. Finally, our data agree with previous findings, suggesting a key role of peripherin in the ALS pathogenesis, thus highlighting that DRG neurons mirror some dysfunctions found in motor neurons. PMID:26908600

  13. Neuroprotective Effect of Bexarotene in the SOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis

    PubMed Central

    Riancho, Javier; Ruiz-Soto, María; Berciano, María T.; Berciano, José; Lafarga, Miguel

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive weakness and muscle atrophy related to the loss of upper and lower motor neurons (MNs) without a curative treatment. There is experimental evidence suggesting that retinoids may be involved in ALS pathogenesis. Bexarotene (Bxt) is a retinoid-X receptor agonist used in the treatment of cutaneous lymphoma with a favorable safety profile whose effects have been recently investigated in other neurodegenerative diseases. In this study, we analyze the potential therapeutic effect of Bxt in the SOD1G93A mouse model of ALS. Mice were treated with Bxt or vehicle five times per week from day 60 onward. Survival, weight, and neuromuscular function studies together with histological and biochemical analyses were performed. Bxt significantly delayed motor function deterioration, ameliorated the loss of body weight, and extended mice survival up to 30% of the symptomatic period. Histological analyses of the lumbosacral spinal cord revealed that Bxt markedly delayed the early motor-neuron degeneration occurring at presymptomatic stages in ALS-transgenic mice. Bxt treatment contributed to preserve the MN homeostasis in the SOD1G93A mice. Particularly, it reduced the neuronal loss and the chromatolytic response, induced nucleolar hypertrophy, decreased the formation of ubiquitylated inclusions, and modulated the lysosomal response. As an agonist of the retinoic-X receptor (RXR) pathway, Bxt notably increased the nuclear expression of the RXRα throughout transcriptionally active euchromatin domains. Bxt also contributed to protect the MN environment by reducing reactive astrogliosis and preserving perisomatic synapsis. Overall, these neuroprotective effects suggest that treatment with Bxt could be useful in ALS, particularly in those cases related to SOD1 mutations. PMID:26190974

  14. Investigation of difficult component effects on finite element model vibration prediction for the Bell AG-1G helicopter. Volume 2: Correlation results

    NASA Technical Reports Server (NTRS)

    Dompka, R. V.

    1989-01-01

    Under the NASA-sponsored DAMVIBS (Design Analysis Methods for VIBrationS) program, a series of ground vibration tests and NASTRAN finite element model (FEM) correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Previous correlations of the AG-1G showed good agreement between NASTRAN and tests through 15 to 20 Hz, but poor agreement in the higher frequency range of 20 to 30 Hz. Thus, this effort emphasized the higher frequency airframe vibration response correlations and identified areas that need further R and T work. To conduct the investigations, selected difficult components (main rotor pylon, secondary structure, nonstructural doors/panels, landing gear, engine, furl, etc.) were systematically removed to quantify their effects on overall vibratory response of the airframe. The entire effort was planned and documented, and the results reviewed by NASA and industry experts in order to ensure scientific control of the testing, analysis, and correlation exercise. In particular, secondary structure and damping had significant effects on the frequency response of the airframe above 15 Hz. Also, the nonlinear effects of thrust stiffening and elastomer mounts were significant on the low frequency pylon modes below main rotor 1p (5.4 Hz). The results of the NASTRAN FEM correlations are given.

  15. Characterization of early pathogenesis in the SOD1G93A mouse model of ALS: part I, background and methods

    PubMed Central

    Vinsant, Sharon; Mansfield, Carol; Jimenez-Moreno, Ramon; Del Gaizo Moore, Victoria; Yoshikawa, Masaaki; Hampton, Thomas G; Prevette, David; Caress, James; Oppenheim, Ronald W; Milligan, Carol

    2013-01-01

    Charcot first described amyotrophic lateral sclerosis (ALS) in 1869; however, its causes remain largely unknown and effective, long-term treatment strategies are not available. The first mouse model of ALS was developed after the identification of mutations in the superoxide dismutase 1 (SOD1) gene in 1993, and accordingly most of our knowledge of the etiology and pathogenesis of the disease comes from studies carried out using this animal model. Although numerous preclinical trials have been conducted in the mutant SOD1 mouse models, the results have been disappointing because they did not positively translate to clinical trials. One explanation may be that current understanding of when and where pathogenesis begins is insufficient to accurately guide preclinical trials. Further characterization of these early events may provide insight into disease onset, help in the discovery of presymptomatic diagnostic disease markers, and identify novel therapeutic targets. Here, we describe the rationale, approach, and methods for our extensive analysis of early changes that included an ultrastructural examination of central and peripheral components of the neuromuscular system in the SOD1G93A mouse and correlated these alterations with early muscle denervation, motor dysfunction, and motoneuron death. We also provide a discussion of published work to review what is known regarding early pathology in the SOD1 mouse model of ALS. The significance of this work is that we have examined early pathology simultaneously in both the spinal cord and peripheral neuromuscular system, and the results are presented in the companion paper (Part II, Results and Discussion). Our results provide evidence as to why a thorough characterization of animal models throughout the life span is critical for a strong foundation to design preclinical trials that may produce meaningful results. PMID:24381807

  16. A hypomorphic mutation of the gamma-1 adaptin gene (Ap1g1) causes inner ear, retina, thyroid, and testes abnormalities in mice.

    PubMed

    Johnson, Kenneth R; Gagnon, Leona H; Chang, Bo

    2016-06-01

    Adaptor protein (AP) complexes function in the intracellular sorting and vesicular transport of membrane proteins. The clathrin-associated AP-1 complex functions at the trans-Golgi network and endosomes, and some forms of this complex are thought to mediate the sorting of proteins in plasma membranes of polarized epithelial cells. A null mutation of the mouse Ap1g1 gene, which encodes the gamma-1 subunit of the AP-1 complex, causes embryonic lethality when homozygous, indicating its critical importance in early development but precluding studies of its possible roles during later stages. Here, we describe our analyses of a new spontaneous mutation of Ap1g1 named "figure eight" (symbol fgt) and show that it is an in-frame deletion of 6 bp, which results in the elimination of two amino acids of the encoded protein. In contrast to Ap1g1 (-/-) null mice, mice homozygous for the recessive fgt mutation are viable with adult survival similar to controls. Although Ap1g1 is ubiquitously expressed, the phenotype of Ap1g1 (fgt) mutant mice is primarily restricted to abnormalities in sensory epithelial cells of the inner ear, pigmented epithelial cells of the retina, follicular epithelial cells of the thyroid gland, and the germinal epithelium of the testis, suggesting that impaired AP-1 sorting and targeting of membrane proteins in these polarized cells may underlie the observed pathologies. Ap1g1 (fgt) mutant mice provide a new animal model to study the in vivo roles of gamma-1 adaptin and the AP-1 complex throughout development and to investigate factors that underlie its associated phenotypic abnormalities. PMID:27090238

  17. Correlation of AH-1G helicopter flight vibration data and tailboom static test data with NASTRAN analytical results

    NASA Technical Reports Server (NTRS)

    Cronkhite, J. D.; Wilson, H. E.; Berry, V. L.

    1976-01-01

    Level flight airframe vibration at main rotor excitation frequencies was calculated. A NASTRAN tailboom analysis was compared with test data for evaluation of methods used to determine effective skin in a semimonocoque sheet-stringer structure. The flight vibration correlation involved comparison of level flight vibration for two helicopter configurations: clean wing, at light gross weight and wing stores at heavy gross weight. In the tailboom correlation, deflections and internal loads were compared using static test data and a NASTRAN analysis. An iterative procedure was used to determine the amount of effective skin of buckled panels under compression load.

  18. Soma size and Cav1.3 channel expression in vulnerable and resistant motoneuron populations of the SOD1G93A mouse model of ALS

    PubMed Central

    Shoenfeld, Liza; Westenbroek, Ruth E.; Fisher, Erika; Quinlan, Katharina A.; Tysseling, Vicki M.; Powers, Randall K.; Heckman, Charles J.; Binder, Marc D.

    2014-01-01

    Abstract Although the loss of motoneurons is an undisputed feature of amyotrophic lateral sclerosis (ALS) in man and in its animal models (SOD1 mutant mice), how the disease affects the size and excitability of motoneurons prior to their degeneration is not well understood. This study was designed to test the hypothesis that motoneurons in mutant SOD1G93A mice exhibit an enlargement of soma size (i.e., cross‐sectional area) and an increase in Cav1.3 channel expression at postnatal day 30, well before the manifestation of physiological symptoms that typically occur at p90 (Chiu et al. 1995). We made measurements of spinal and hypoglossal motoneurons vulnerable to degeneration, as well as motoneurons in the oculomotor nucleus that are resistant to degeneration. Overall, we found that the somata of motoneurons in male SOD1G93A mutants were larger than those in wild‐type transgenic males. When females were included in the two groups, significance was lost. Expression levels of the Cav1.3 channels were not differentiated by genotype, sex, or any interaction of the two. These results raise the intriguing possibility of an interaction between male sex steroid hormones and the SOD1 mutation in the etiopathogenesis of ALS. PMID:25107988

  19. Early gene expression changes in skeletal muscle from SOD1(G93A) amyotrophic lateral sclerosis animal model.

    PubMed

    de Oliveira, Gabriela P; Maximino, Jessica R; Maschietto, Mariana; Zanoteli, Edmar; Puga, Renato D; Lima, Leandro; Carraro, Dirce M; Chadi, Gerson

    2014-04-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by loss of motor neurons. Familial ALS is strongly associated to dominant mutations in the gene for Cu/Zn superoxide dismutase (SOD1). Recent evidences point to skeletal muscle as a primary target in the ALS mouse model. Wnt/PI3 K signaling pathways and epithelial-mesenchymal transition (EMT) have important roles in maintenance and repair of skeletal muscle. Wnt/PI3 K pathways and EMT gene expression profile were investigated in gastrocnemius muscle from SOD1(G93A) mouse model and age-paired wild-type control in the presymptomatic ages of 40 and 80 days aiming the early neuromuscular abnormalities that precede motor neuron death in ALS. A customized cDNA microarray platform containing 326 genes of Wnt/PI3 K and EMT was used and results revealed eight up-regulated (Loxl2, Pik4ca, Fzd9, Cul1, Ctnnd1, Snf1lk, Prkx, Dner) and nine down-regulated (Pik3c2a, Ripk4, Id2, C1qdc1, Eif2ak2, Rac3, Cds1, Inppl1, Tbl1x) genes at 40 days, and also one up-regulated (Pik3ca) and five down-regulated (Cd44, Eef2 k, Fzd2, Crebbp, Piki3r1) genes at 80 days. Also, protein-protein interaction networks grown from the differentially expressed genes of 40 and 80 days old mice have identified Grb2 and Src genes in both presymptomatic ages, thus playing a potential central role in the disease mechanisms. mRNA and protein levels for Grb2 and Src were found to be increased in 80 days old ALS mice. Gene expression changes in the skeletal muscle of transgenic ALS mice at presymptomatic periods of disease gave further evidence of early neuromuscular abnormalities that precede motor neuron death. The results were discussed in terms of initial triggering for neuronal degeneration and muscle adaptation to keep function before the onset of symptoms. PMID:24442855

  20. Acute Traumatic Brain Injury Does Not Exacerbate Amyotrophic Lateral Sclerosis in the SOD1 (G93A) Rat Model(1,2,3).

    PubMed

    Thomsen, Gretchen M; Vit, Jean-Philippe; Lamb, Alexander; Gowing, Genevieve; Shelest, Oksana; Alkaslasi, Mor; Ley, Eric J; Svendsen, Clive N

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease in which upper and lower motor neurons degenerate, leading to muscle atrophy, paralysis, and death within 3 to 5 years of onset. While a small percentage of ALS cases are genetically linked, the majority are sporadic with unknown origin. Currently, etiological links are associated with disease onset without mechanistic understanding. Of all the putative risk factors, however, head trauma has emerged as a consistent candidate for initiating the molecular cascades of ALS. Here, we test the hypothesis that traumatic brain injury (TBI) in the SOD1 (G93A) transgenic rat model of ALS leads to early disease onset and shortened lifespan. We demonstrate, however, that a one-time acute focal injury caused by controlled cortical impact does not affect disease onset or survival. Establishing the negligible involvement of a single acute focal brain injury in an ALS rat model increases the current understanding of the disease. Critically, untangling a single focal TBI from multiple mild injuries provides a rationale for scientists and physicians to increase focus on repeat injuries to hopefully pinpoint a contributing cause of ALS. PMID:26464984

  1. Sensorimotor and cognitive functions in a SOD1(G37R) transgenic mouse model of amyotrophic lateral sclerosis.

    PubMed

    Filali, Mohammed; Lalonde, Robert; Rivest, Serge

    2011-11-20

    Amyotrophic lateral sclerosis (ALS) is a neurological disorder involving degeneration of motor neurons in brain and spinal cord, leading to progressive atrophy of skeletal muscles and, ultimately, paralysis and death. Copper-mediated oxidative damage is proposed to play a critical role in the pathogenesis of Cu/Zn superoxide dismutase (SOD1) - linked hereditary amyotrophic lateral sclerosis. To understand more clearly the pathogenesis of sensorimotor dysfunction and to find the most appropriate methods for early detection of symptoms and for monitoring them across time, a murine model was assessed at three time points (5, 8, and 11 months). Transgenic mice with the G37R mutation of human SOD1 exhibited earliest signs of dysfunction at 8 months in terms of a pathological hindpaw clasping reflex, as well as slowed movement time on a suspended bar, anomalies in footprint patterns, weaker grip strength, raised somatosensory thresholds, and deficits in passive avoidance learning, yielding a margin of 3-4 months before death to test experimental therapies. PMID:21816178

  2. Administration of 4-(α-L-rhamnosyloxy)-benzyl isothiocyanate delays disease phenotype in SOD1(G93A) rats: a transgenic model of amyotrophic lateral sclerosis.

    PubMed

    Galuppo, Maria; Giacoppo, Sabrina; Iori, Renato; De Nicola, Gina Rosalinda; Bramanti, Placido; Mazzon, Emanuela

    2015-01-01

    4-(α-L-Rhamnosyloxy)-benzyl glucosinolate (glucomoringin, GMG) is a compound found in Moringa oleifera seeds. Myrosinase-catalyzed hydrolysis at neutral pH of GMG releases the biologically active compound 4-(α-L-rhamnosyloxy)-benzyl isothiocyanate (GMG-ITC). The present study was designed to test the potential therapeutic effectiveness of GMG-ITC to counteract the amyotrophic lateral sclerosis (ALS) using SOD1tg rats, which physiologically develops SOD1(G93A) at about 16 weeks of life, and can be considered a genetic model of disease. Rats were treated once a day with GMG (10 mg/Kg) bioactivated with myrosinase (20 µL/rat) via intraperitoneal (i.p.) injection for two weeks before disease onset and the treatment was prolonged for further two weeks before the sacrifice. Immune-inflammatory markers as well as apoptotic pathway were investigated to establish whether GMG-ITC could represent a new promising tool in clinical practice to prevent ALS. Achieved data display clear differences in molecular and biological profiles between treated and untreated SOD1tg rats leading to guessing that GMG-ITC can interfere with the pathophysiological mechanisms at the basis of ALS development. Therefore, GMG-ITC produced from myrosinase-catalyzed hydrolysis of pure GMG could be a candidate for further studies aimed to assess its possible use in clinical practice for the prevention or to slow down this disease. PMID:26075221

  3. Administration of 4-(α-L-Rhamnosyloxy)-benzyl Isothiocyanate Delays Disease Phenotype in SOD1G93A Rats: A Transgenic Model of Amyotrophic Lateral Sclerosis

    PubMed Central

    De Nicola, Gina Rosalinda; Mazzon, Emanuela

    2015-01-01

    4-(α-L-Rhamnosyloxy)-benzyl glucosinolate (glucomoringin, GMG) is a compound found in Moringa oleifera seeds. Myrosinase-catalyzed hydrolysis at neutral pH of GMG releases the biologically active compound 4-(α-L-rhamnosyloxy)-benzyl isothiocyanate (GMG-ITC). The present study was designed to test the potential therapeutic effectiveness of GMG-ITC to counteract the amyotrophic lateral sclerosis (ALS) using SOD1tg rats, which physiologically develops SOD1G93A at about 16 weeks of life, and can be considered a genetic model of disease. Rats were treated once a day with GMG (10 mg/Kg) bioactivated with myrosinase (20 µL/rat) via intraperitoneal (i.p.) injection for two weeks before disease onset and the treatment was prolonged for further two weeks before the sacrifice. Immune-inflammatory markers as well as apoptotic pathway were investigated to establish whether GMG-ITC could represent a new promising tool in clinical practice to prevent ALS. Achieved data display clear differences in molecular and biological profiles between treated and untreated SOD1tg rats leading to guessing that GMG-ITC can interfere with the pathophysiological mechanisms at the basis of ALS development. Therefore, GMG-ITC produced from myrosinase-catalyzed hydrolysis of pure GMG could be a candidate for further studies aimed to assess its possible use in clinical practice for the prevention or to slow down this disease. PMID:26075221

  4. Comparative morphometric analysis of microglia in the spinal cord of SOD1(G93A) transgenic mouse model of amyotrophic lateral sclerosis.

    PubMed

    Ohgomori, Tomohiro; Yamada, Jun; Takeuchi, Hideyuki; Kadomatsu, Kenji; Jinno, Shozo

    2016-05-01

    It has long been recognized that reactive microglia undergo a series of phenotypic changes accompanying morphological transformation. However, the morphological classification of microglia has not yet been achieved. To address this issue, here we morphometrically analysed three-dimensionally reconstructed ionized calcium binding adaptor molecule 1-immunoreactive (Iba1(+) ) microglia in the ventral horn of the lumbar spinal cord of SOD1(G93A) transgenic mice, a model of amyotrophic lateral sclerosis. The hierarchical cluster analysis revealed that microglia were objectively divided into four groups: type S (named after surveillant microglia) and types R1, R2 and R3 (named after reactive microglia). For the purpose of comparative morphometry, we also analysed two pharmacological disease models using wild-type mice: 3,3'-iminodipropionitrile (IDPN)-induced axonopathy and lipopolysaccharide (LPS)-induced neuroinflammation. Type S microglia showed a typical ramified morphology of surveillant microglia, and were mostly observed in wild-type controls. Type R1 microglia were seen at the early stage of disease in SOD1(G93A) mice, and also frequently occurred in IDPN-treated mice. They exhibited small cell bodies with shorter and simple processes. Type R2 microglia were morphologically similar to type R1 microglia, but only transiently occurred in the middle stage of disease in SOD1(G93A) mice and in IDPN-treated mice. Type R3 microglia exhibited a bushy shape, and were observed in the end stage of disease in SOD1(G93A) mice and in LPS-treated mice. These findings indicate that microglia of SOD1(G93A) mice can be classified into four types, and also suggest that the phenotypic changes may be induced by the events related to axonopathy and neuroinflammation. PMID:26946061

  5. Lysosomal and phagocytic activity is increased in astrocytes during disease progression in the SOD1 G93A mouse model of amyotrophic lateral sclerosis

    PubMed Central

    Baker, David J.; Blackburn, Daniel J.; Keatinge, Marcus; Sokhi, Dilraj; Viskaitis, Paulius; Heath, Paul R.; Ferraiuolo, Laura; Kirby, Janine; Shaw, Pamela J.

    2015-01-01

    Astrocytes are key players in the progression of amyotrophic lateral sclerosis (ALS). Previously, gene expression profiling of astrocytes from the pre-symptomatic stage of the SOD1G93A model of ALS has revealed reduced lactate metabolism and altered trophic support. Here, we have performed microarray analysis of symptomatic and late-stage disease astrocytes isolated by laser capture microdissection (LCM) from the lumbar spinal cord of the SOD1G93A mouse to complete the picture of astrocyte behavior throughout the disease course. Astrocytes at symptomatic and late-stage disease show a distinct up-regulation of transcripts defining a reactive phenotype, such as those involved in the lysosome and phagocytic pathways. Functional analysis of hexosaminidase B enzyme activity in the spinal cord and of astrocyte phagocytic ability has demonstrated a significant increase in lysosomal enzyme activity and phagocytic activity in SOD1G93A vs. littermate controls, validating the findings of the microarray study. In addition to the increased reactivity seen at both stages, astrocytes from late-stage disease showed decreased expression of many transcripts involved in cholesterol homeostasis. Staining for the master regulator of cholesterol synthesis, SREBP2, has revealed an increased localization to the cytoplasm of astrocytes and motor neurons in late-stage SOD1G93A spinal cord, indicating that down-regulation of transcripts may be due to an excess of cholesterol in the CNS during late-stage disease possibly due to phagocytosis of neuronal debris. Our data reveal that SOD1G93A astrocytes are characterized more by a loss of supportive function than a toxic phenotype during ALS disease progression and future studies should focus upon restorative therapies. PMID:26528138

  6. Fast Skeletal Muscle Troponin Activator tirasemtiv Increases Muscle Function and Performance in the B6SJL-SOD1G93A ALS Mouse Model

    PubMed Central

    Ryans, Julie; Russell, Alan J.; Jia, Zhiheng; Hinken, Aaron C.; Morgans, David J.; Malik, Fady I.; Jasper, Jeffrey R.

    2014-01-01

    Amyotrophic Lateral Sclerosis (ALS) is a motor neuron disease characterized by progressive motor neuron loss resulting in muscle atrophy, declining muscle function, and eventual paralysis. Patients typically die from respiratory failure 3 to 5 years from the onset of symptoms. Tirasemtiv is a fast skeletal troponin activator that sensitizes the sarcomere to calcium; this mechanism of action amplifies the response of muscle to neuromuscular input producing greater force when nerve input is reduced. Here, we demonstrate that a single dose of tirasemtiv significantly increases submaximal isometric force, forelimb grip strength, grid hang time, and rotarod performance in a female transgenic mouse model (B6SJL-SOD1G93A) of ALS with functional deficits. Additionally, diaphragm force and tidal volume are significantly higher in tirasemtiv-treated female B6SJL-SOD1G93A mice. These results support the potential of fast skeletal troponin activators to improve muscle function in neuromuscular diseases. PMID:24805850

  7. Defining peripheral nervous system dysfunction in the SOD-1G93A transgenic rat model of amyotrophic lateral sclerosis.

    PubMed

    Riva, Nilo; Chaabane, Linda; Peviani, Marco; Ungaro, Daniela; Domi, Teuta; Dina, Giorgia; Bianchi, Francesca; Spano, Giorgia; Cerri, Federica; Podini, Paola; Corbo, Massimo; Carro, Ubaldo Del; Comi, Giancarlo; Bendotti, Caterina; Quattrini, Angelo

    2014-07-01

    Growing evidence indicates that alterations within the peripheral nervous system (PNS) are involved at an early stage in the amyotrophic lateral sclerosis (ALS) pathogenetic cascade. In this study, magnetic resonance imaging (MRI), neurophysiologic analyses, and histologic analyses were used to monitor the extent of PNS damage in the hSOD-1 ALS rat model. The imaging signature of the disease was defined using in vivo MRI of the sciatic nerve. Initial abnormalities were detected in the nerves by an increase in T2 relaxation time before the onset of clinical disease; diffusion MRI showed a progressive increase in mean and radial diffusivity and reduction of fractional anisotropy at advanced stages of disease. Histologic analysis demonstrated early impairment of the blood-nerve barrier followed by acute axonal degeneration associated with endoneurial edema and macrophage response in motor nerve compartments. Progressive axonal degeneration and motor nerve fiber loss correlated with MRI and neurophysiologic changes. These functional and morphologic investigations of the PNS might be applied in following disease progression in preclinical therapeutic studies. This study establishes the PNS signature in this rat ALS model (shedding new light into pathogenesis) and provides a rationale for translating into future systematic MRI studies of PNS involvement in patients with ALS. PMID:24918640

  8. Gene expression changes in spinal motoneurons of the SOD1G93A transgenic model for ALS after treatment with G-CSF

    PubMed Central

    Henriques, Alexandre; Kastner, Stefan; Chatzikonstantinou, Eva; Pitzer, Claudia; Plaas, Christian; Kirsch, Friederike; Wafzig, Oliver; Krüger, Carola; Spoelgen, Robert; Gonzalez De Aguilar, Jose-Luis; Gretz, Norbert; Schneider, Armin

    2015-01-01

    Background: Amyotrophic lateral sclerosis (ALS) is an incurable fatal motoneuron disease with a lifetime risk of approximately 1:400. It is characterized by progressive weakness, muscle wasting, and death ensuing 3–5 years after diagnosis. Granulocyte-colony stimulating factor (G-CSF) is a drug candidate for ALS, with evidence for efficacy from animal studies and interesting data from pilot clinical trials. To gain insight into the disease mechanisms and mode of action of G-CSF, we performed gene expression profiling on isolated lumbar motoneurons from SOD1G93A mice, the most frequently studied animal model for ALS, with and without G-CSF treatment. Results: Motoneurons from SOD1G93A mice present a distinct gene expression profile in comparison to controls already at an early disease stage (11 weeks of age), when treatment was initiated. The degree of deregulation increases at a time where motor symptoms are obvious (15 weeks of age). Upon G-CSF treatment, transcriptomic deregulations of SOD1G93A motoneurons were notably restored. Discriminant analysis revealed that SOD1 mice treated with G-CSF has a transcriptom close to presymptomatic SOD1 mice or wild type mice. Some interesting genes modulated by G-CSF treatment relate to neuromuscular function such as CCR4-NOT or Prss12. Conclusions: Our data suggest that G-CSF is able to re-adjust gene expression in symptomatic SOD1G93A motoneurons. This provides further arguments for G-CSF as a promising drug candidate for ALS. PMID:25653590

  9. Plasma Neurofilament Heavy Chain Levels Correlate to Markers of Late Stage Disease Progression and Treatment Response in SOD1G93A Mice that Model ALS

    PubMed Central

    Lu, Ching-Hua; Petzold, Axel; Kalmar, Bernadett; Dick, James; Malaspina, Andrea; Greensmith, Linda

    2012-01-01

    Background Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disorder characterised by progressive degeneration of motor neurons leading to death, typically within 3–5 years of symptom onset. The diagnosis of ALS is largely reliant on clinical assessment and electrophysiological findings. Neither specific investigative tools nor reliable biomarkers are currently available to enable an early diagnosis or monitoring of disease progression, hindering the design of treatment trials. Methodology/Principal Findings In this study, using the well-established SOD1G93A mouse model of ALS and a new in-house ELISA method, we have validated that plasma neurofilament heavy chain protein (NfH) levels correlate with both functional markers of late stage disease progression and treatment response. We detected a significant increase in plasma levels of phosphorylated NfH during disease progression in SOD1G93A mice from 105 days onwards. Moreover, increased plasma NfH levels correlated with the decline in muscle force, motor unit survival and, more significantly, with the loss of spinal motor neurons in SOD1 mice during this critical period of decline. Importantly, mice treated with the disease modifying compound arimoclomol had lower plasma NfH levels, suggesting plasma NfH levels could be validated as an outcome measure for treatment trials. Conclusions/Significance These results show that plasma NfH levels closely reflect later stages of disease progression and therapeutic response in the SOD1G93A mouse model of ALS and may potentially be a valuable biomarker of later disease progression in ALS. PMID:22815892

  10. Iron-sulfur cluster damage by the superoxide radical in neural tissues of the SOD1(G93A) ALS rat model.

    PubMed

    Popović-Bijelić, Ana; Mojović, Miloš; Stamenković, Stefan; Jovanović, Miloš; Selaković, Vesna; Andjus, Pavle; Bačić, Goran

    2016-07-01

    Extensive clinical investigations, in hand with biochemical and biophysical research, have associated brain iron accumulation with the pathogenesis of the amyotrophic lateral sclerosis (ALS) disease. The origin of iron is still not identified, but it is proposed that it forms redox active complexes that can participate in the Fenton reaction generating the toxic hydroxyl radical. In this paper, the state of iron in the neural tissues isolated from SOD1(G93A) transgenic rats was investigated using low temperature EPR spectroscopy and is compared with that of nontransgenic (NTg) littermates. The results showed that iron in neural tissues is present as high- and low-spin, heme and non-heme iron. It appears that the SOD1(G93A) rat neural tissues were most likely exposed in vivo to higher amounts of reactive oxygen species when compared to the corresponding NTg tissues, as they showed increased oxidized [3Fe-4S](1+) cluster content relative to [4Fe-4S](1+). Also, the activity of cytochrome c oxidase (CcO) was found to be reduced in these tissues, which may be associated with the observed uncoupling of heme a3 Fe and CuB in the O2-reduction site of the enzyme. Furthermore, the SOD1(G93A) rat spinal cords and brainstems contained more manganese, presumably from MnSOD, than those of NTg rats. The addition of potassium superoxide to all neural tissues ex vivo, led to the [4Fe-4S]→[3Fe-4S] cluster conversion and concurrent release of Fe. These results suggest that the superoxide anion may be the cause of the observed oxidative damage to SOD1(G93A) rat neural tissues and that the iron-sulfur clusters may be the source of poorly liganded redox active iron implicated in ALS pathogenesis. Low temperature EPR spectroscopy appears to be a valuable tool in assessing the role of metals in neurodegenerative diseases. PMID:27130034

  11. State of the field: An informatics-based systematic review of the SOD1-G93A amyotrophic lateral sclerosis transgenic mouse model.

    PubMed

    Kim, Renaid B; Irvin, Cameron W; Tilva, Keval R; Mitchell, Cassie S

    2015-01-01

    Numerous sub-cellular through system-level disturbances have been identified in over 1300 articles examining the superoxide dismutase-1 guanine 93 to alanine (SOD1-G93A) transgenic mouse amyotrophic lateral sclerosis (ALS) pathophysiology. Manual assessment of such a broad literature base is daunting. We performed a comprehensive informatics-based systematic review or 'field analysis' to agnostically compute and map the current state of the field. Text mining of recaptured articles was used to quantify published data topic breadth and frequency. We constructed a nine-category pathophysiological function-based ontology to systematically organize and quantify the field's primary data. Results demonstrated that the distribution of primary research belonging to each category is: systemic measures an motor function, 59%; inflammation, 46%; cellular energetics, 37%; proteomics, 31%; neural excitability, 22%; apoptosis, 20%; oxidative stress, 18%; aberrant cellular chemistry, 14%; axonal transport, 10%. We constructed a SOD1-G93A field map that visually illustrates and categorizes the 85% most frequently assessed sub-topics. Finally, we present the literature-cited significance of frequently published terms and uncover thinly investigated areas. In conclusion, most articles individually examine at least two categories, which is indicative of the numerous underlying pathophysiological interrelationships. An essential future path is examination of cross-category pathophysiological interrelationships and their co-correspondence to homeostatic regulation and disease progression. PMID:25998063

  12. State of the field: An informatics-based systematic review of the SOD1-G93A amyotrophic lateral sclerosis transgenic mouse model

    PubMed Central

    Kim, Renaid B.; Irvin, Cameron W.; Tilva, Keval R.; Mitchell, Cassie S.

    2016-01-01

    Numerous sub-cellular through system-level disturbances have been identified in over 1300 articles examining the superoxide dismutase-1 guanine 93 to alanine (SOD1-G93A) transgenic mouse amyotrophic lateral sclerosis (ALS) pathophysiology. Manual assessment of such a broad literature base is daunting. We performed a comprehensive informatics-based systematic review or ‘field analysis’ to agnostically compute and map the current state of the field. Text mining of recaptured articles was used to quantify published data topic breadth and frequency. We constructed a nine-category pathophysiological function-based ontology to systematically organize and quantify the field's primary data. Results demonstrated that the distribution of primary research belonging to each category is: systemic measures an motor function, 59%; inflammation, 46%; cellular energetics, 37%; proteomics, 31%; neural excitability, 22%; apoptosis, 20%; oxidative stress, 18%; aberrant cellular chemistry, 14%; axonal transport, 10%. We constructed a SOD1-G93A field map that visually illustrates and categorizes the 85% most frequently assessed sub-topics. Finally, we present the literature-cited significance of frequently published terms and uncover thinly investigated areas. In conclusion, most articles individually examine at least two categories, which is indicative of the numerous underlying pathophysiological interrelationships. An essential future path is examination of cross-category pathophysiological interrelationships and their co-correspondence to homeostatic regulation and disease progression. PMID:25998063

  13. Deregulated expression of cytoskeleton related genes in the spinal cord and sciatic nerve of presymptomatic SOD1G93A Amyotrophic Lateral Sclerosis mouse model

    PubMed Central

    Maximino, Jessica R.; de Oliveira, Gabriela P.; Alves, Chrystian J.; Chadi, Gerson

    2014-01-01

    Early molecular events related to cytoskeleton are poorly described in Amyotrophic Lateral Sclerosis (ALS), especially in the Schwann cell (SC), which offers strong trophic support to motor neurons. Database for Annotation, Visualization and Integrated Discovery (DAVID) tool identified cytoskeleton-related genes by employing the Cellular Component Ontology (CCO) in a large gene profiling of lumbar spinal cord and sciatic nerve of presymptomatic SOD1G93A mice. One and five CCO terms related to cytoskeleton were described from the spinal cord deregulated genes of 40 days (actin cytoskeleton) and 80 days (microtubule cytoskeleton, cytoskeleton part, actin cytoskeleton, neurofilament cytoskeleton, and cytoskeleton) old transgene mice, respectively. Also, four terms were depicted from the deregulated genes of sciatic nerve of 60 days old transgenes (actin cytoskeleton, cytoskeleton part, microtubule cytoskeleton and cytoskeleton). Kif1b was the unique deregulated gene in more than one studied region or presymptomatic age. The expression of Kif1b [quantitative polymerase chain reaction (qPCR)] elevated in the lumbar spinal cord (40 days old) and decreased in the sciatic nerve (60 days old) of presymptomatic ALS mice, results that were in line to microarray findings. Upregulation (24.8 fold) of Kif1b was seen in laser microdissected enriched immunolabeled motor neurons from the spinal cord of 40 days old presymptomatic SOD1G93A mice. Furthermore, Kif1b was dowregulated in the sciatic nerve Schwann cells of presymptomatic ALS mice (60 days old) that were enriched by means of cell microdissection (6.35 fold), cell sorting (3.53 fold), and primary culture (2.70 fold) technologies. The gene regulation of cytoskeleton molecules is an important occurrence in motor neurons and Schwann cells in presymptomatic stages of ALS and may be relevant in the dying back mechanisms of neuronal death. Furthermore, a differential regulation of Kif1b in the spinal cord and sciatic nerve cells

  14. Dysregulated expression of death, stress and mitochondrion related genes in the sciatic nerve of presymptomatic SOD1G93A mouse model of Amyotrophic Lateral Sclerosis

    PubMed Central

    Alves, Chrystian J.; Maximino, Jessica R.; Chadi, Gerson

    2015-01-01

    Schwann cells are the main source of paracrine support to motor neurons. Oxidative stress and mitochondrial dysfunction have been correlated to motor neuron death in Amyotrophic Lateral Sclerosis (ALS). Despite the involvement of Schwann cells in early neuromuscular disruption in ALS, detailed molecular events of a dying-back triggering are unknown. Sciatic nerves of presymptomatic (60-day-old) SOD1G93A mice were submitted to a high-density oligonucleotide microarray analysis. DAVID demonstrated the deregulated genes related to death, stress and mitochondrion, which allowed the identification of Cell cycle, ErbB signaling, Tryptophan metabolism and Rig-I-like receptor signaling as the most representative KEGG pathways. The protein-protein interaction networks based upon deregulated genes have identified the top hubs (TRAF2, H2AFX, E2F1, FOXO3, MSH2, NGFR, TGFBR1) and bottlenecks (TRAF2, E2F1, CDKN1B, TWIST1, FOXO3). Schwann cells were enriched from the sciatic nerve of presymptomatic mice using flow cytometry cell sorting. qPCR showed the up regulated (Ngfr, Cdnkn1b, E2f1, Traf2 and Erbb3, H2afx, Cdkn1a, Hspa1, Prdx, Mapk10) and down-regulated (Foxo3, Mtor) genes in the enriched Schwann cells. In conclusion, molecular analyses in the presymptomatic sciatic nerve demonstrated the involvement of death, oxidative stress, and mitochondrial pathways in the Schwann cell non-autonomous mechanisms in the early stages of ALS. PMID:26339226

  15. A Cystine-Rich Whey Supplement (Immunocal(®)) Delays Disease Onset and Prevents Spinal Cord Glutathione Depletion in the hSOD1(G93A) Mouse Model of Amyotrophic Lateral Sclerosis.

    PubMed

    Ross, Erika K; Winter, Aimee N; Wilkins, Heather M; Sumner, Whitney A; Duval, Nathan; Patterson, David; Linseman, Daniel A

    2014-01-01

    Depletion of the endogenous antioxidant, glutathione (GSH), underlies progression of the devastating neurodegenerative disease, amyotrophic lateral sclerosis (ALS). Thus, strategies aimed at elevating GSH may yield new therapeutics for ALS. Here, we investigated the effects of a unique non-denatured whey protein supplement, Immunocal(®), in the transgenic Gly position 93 to Ala (G93A) mutant hSOD1 (hSOD1(G93A)) mouse model of ALS. Immunocal(®) is rich in the GSH precursor, cystine, and is therefore capable of bolstering GSH content. Transgenic hSOD1(G93A) mice receiving Immunocal(®) displayed a significant delay in disease onset compared to untreated hSOD1(G93A) controls. Additionally, Immunocal(®) treatment significantly decreased the rate of decline in grip strength and prevented disease-associated reductions in whole blood and spinal cord tissue GSH levels in end-stage hSOD1(G93A) mice. However, Immunocal(®) did not extend survival, likely due to its inability to preserve the mitochondrial GSH pool in spinal cord. Combination treatment with Immunocal(®) and the anti-glutamatergic compound, riluzole, delayed disease onset and extended survival in hSOD1(G93A) mice. These findings demonstrate that sustaining tissue GSH with Immunocal(®) only modestly delays disease onset and slows the loss of skeletal muscle strength in hSOD1(G93A) mice. Moreover, the inability of Immunocal(®) to rescue mitochondrial GSH in spinal cord provides a possible mechanism for its lack of effect on survival and is a limiting factor in the potential utility of this supplement as a therapeutic for ALS. PMID:26785244

  16. A Cystine-Rich Whey Supplement (Immunocal®) Delays Disease Onset and Prevents Spinal Cord Glutathione Depletion in the hSOD1G93A Mouse Model of Amyotrophic Lateral Sclerosis

    PubMed Central

    Ross, Erika K.; Winter, Aimee N.; Wilkins, Heather M.; Sumner, Whitney A.; Duval, Nathan; Patterson, David; Linseman, Daniel A.

    2014-01-01

    Depletion of the endogenous antioxidant, glutathione (GSH), underlies progression of the devastating neurodegenerative disease, amyotrophic lateral sclerosis (ALS). Thus, strategies aimed at elevating GSH may yield new therapeutics for ALS. Here, we investigated the effects of a unique non-denatured whey protein supplement, Immunocal®, in the transgenic Gly position 93 to Ala (G93A) mutant hSOD1 (hSOD1G93A) mouse model of ALS. Immunocal® is rich in the GSH precursor, cystine, and is therefore capable of bolstering GSH content. Transgenic hSOD1G93A mice receiving Immunocal® displayed a significant delay in disease onset compared to untreated hSOD1G93A controls. Additionally, Immunocal® treatment significantly decreased the rate of decline in grip strength and prevented disease-associated reductions in whole blood and spinal cord tissue GSH levels in end-stage hSOD1G93A mice. However, Immunocal® did not extend survival, likely due to its inability to preserve the mitochondrial GSH pool in spinal cord. Combination treatment with Immunocal® and the anti-glutamatergic compound, riluzole, delayed disease onset and extended survival in hSOD1G93A mice. These findings demonstrate that sustaining tissue GSH with Immunocal® only modestly delays disease onset and slows the loss of skeletal muscle strength in hSOD1G93A mice. Moreover, the inability of Immunocal® to rescue mitochondrial GSH in spinal cord provides a possible mechanism for its lack of effect on survival and is a limiting factor in the potential utility of this supplement as a therapeutic for ALS. PMID:26785244

  17. Depressed excitability and ion currents linked to slow exocytotic fusion pore in chromaffin cells of the SOD1(G93A) mouse model of amyotrophic lateral sclerosis.

    PubMed

    Calvo-Gallardo, Enrique; de Pascual, Ricardo; Fernández-Morales, José-Carlos; Arranz-Tagarro, Juan-Alberto; Maroto, Marcos; Nanclares, Carmen; Gandía, Luis; de Diego, Antonio M G; Padín, Juan-Fernando; García, Antonio G

    2015-01-01

    Altered synaptic transmission with excess glutamate release has been implicated in the loss of motoneurons occurring in amyotrophic lateral sclerosis (ALS). Hyperexcitability or hypoexcitability of motoneurons from mice carrying the ALS mutation SOD1(G93A) (mSOD1) has also been reported. Here we have investigated the excitability, the ion currents, and the kinetics of the exocytotic fusion pore in chromaffin cells from postnatal day 90 to postnatal day 130 mSOD1 mice, when motor deficits are already established. With respect to wild-type (WT), mSOD1 chromaffin cells had a decrease in the following parameters: 95% in spontaneous action potentials, 70% in nicotinic current for acetylcholine (ACh), 35% in Na(+) current, 40% in Ca(2+)-dependent K(+) current, and 53% in voltage-dependent K(+) current. Ca(2+) current was increased by 37%, but the ACh-evoked elevation of cytosolic Ca(2+) was unchanged. Single exocytotic spike events triggered by ACh had the following differences (mSOD1 vs. WT): 36% lower rise rate, 60% higher decay time, 51% higher half-width, 13% lower amplitude, and 61% higher quantal size. The expression of the α3-subtype of nicotinic receptors and proteins of the exocytotic machinery was unchanged in the brain and adrenal medulla of mSOD1, with respect to WT mice. A slower fusion pore opening, expansion, and closure are likely linked to the pronounced reduction in cell excitability and in the ion currents driving action potentials in mSOD1, compared with WT chromaffin cells. PMID:25377090

  18. Mice Overexpressing Both Non-Mutated Human SOD1 and Mutated SOD1G93A Genes: A Competent Experimental Model for Studying Iron Metabolism in Amyotrophic Lateral Sclerosis

    PubMed Central

    Gajowiak, Anna; Styś, Agnieszka; Starzyński, Rafał R.; Bednarz, Aleksandra; Lenartowicz, Małgorzata; Staroń, Robert; Lipiński, Paweł

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by degeneration and loss of motor neurons in the spinal cord, brainstem and motor cortex. Up to 10% of ALS cases are inherited (familial, fALS) and associated with mutations, frequently in the superoxide dismutase 1 (SOD1) gene. Rodent transgenic models of ALS are often used to elucidate a complex pathogenesis of this disease. Of importance, both ALS patients and animals carrying mutated human SOD1 gene show symptoms of oxidative stress and iron metabolism misregulation. The aim of our study was to characterize changes in iron metabolism in one of the most commonly used models of ALS – transgenic mice overexpressing human mutated SOD1G93A gene. We analyzed the expression of iron-related genes in asymptomatic, 2-month-old and symptomatic, 4-month-old SOD1G93A mice. In parallel, respective age-matched mice overexpressing human non-mutated SOD1 transgene and control mice were analyzed. We demonstrate that the overexpression of both SOD1 and SOD1G93A genes account for a substantial increase in SOD1 protein levels and activity in selected tissues and that not all the changes in iron metabolism genes expression are specific for the overexpression of the mutated form of SOD1. PMID:26778957

  19. A comprehensive assessment of the SOD1G93A low-copy transgenic mouse, which models human amyotrophic lateral sclerosis.

    PubMed

    Acevedo-Arozena, Abraham; Kalmar, Bernadett; Essa, Shafa; Ricketts, Thomas; Joyce, Peter; Kent, Rosie; Rowe, Claire; Parker, Andy; Gray, Anna; Hafezparast, Majid; Thorpe, Julian R; Greensmith, Linda; Fisher, Elizabeth M C

    2011-09-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that results in the death of motor neurons in the brain and spinal cord. The disorder generally strikes in mid-life, relentlessly leading to paralysis and death, typically 3-5 years after diagnosis. No effective treatments are available. Up to 10% of ALS is familial, usually autosomal dominant. Several causative genes are known and, of these, mutant superoxide dismutase 1 (SOD1) is by far the most frequently found, accounting for up to 20% of familial ALS. A range of human mutant SOD1 transgenic mouse strains has been produced, and these largely successfully model the human disease. Of these, the most widely used is the SOD1 mouse, which expresses a human SOD1 transgene with a causative G93A mutation. This mouse model is excellent for many purposes but carries up to 25 copies of the transgene and produces a great excess of SOD1 protein, which might affect our interpretation of disease processes. A variant of this strain carries a deletion of the transgene array such that the copy number is dropped to eight to ten mutant SOD1 genes. This 'deleted' 'low-copy' mouse undergoes a slower course of disease, over many months. Here we have carried out a comprehensive analysis of phenotype, including nerve and muscle physiology and histology, to add to our knowledge of this 'deleted' strain and give baseline data for future studies. We find differences in phenotype that arise from genetic background and sex, and we quantify the loss of nerve and muscle function over time. The slowly progressive pathology observed in this mouse strain could provide us with a more appropriate model for studying early-stage pathological processes in ALS and aid the development of therapies for early-stage treatments. PMID:21540242

  20. A comprehensive assessment of the SOD1G93A low-copy transgenic mouse, which models human amyotrophic lateral sclerosis

    PubMed Central

    Acevedo-Arozena, Abraham; Kalmar, Bernadett; Essa, Shafa; Ricketts, Thomas; Joyce, Peter; Kent, Rosie; Rowe, Claire; Parker, Andy; Gray, Anna; Hafezparast, Majid; Thorpe, Julian R.; Greensmith, Linda; Fisher, Elizabeth M. C.

    2011-01-01

    SUMMARY Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder that results in the death of motor neurons in the brain and spinal cord. The disorder generally strikes in mid-life, relentlessly leading to paralysis and death, typically 3–5 years after diagnosis. No effective treatments are available. Up to 10% of ALS is familial, usually autosomal dominant. Several causative genes are known and, of these, mutant superoxide dismutase 1 (SOD1) is by far the most frequently found, accounting for up to 20% of familial ALS. A range of human mutant SOD1 transgenic mouse strains has been produced, and these largely successfully model the human disease. Of these, the most widely used is the SOD1 mouse, which expresses a human SOD1 transgene with a causative G93A mutation. This mouse model is excellent for many purposes but carries up to 25 copies of the transgene and produces a great excess of SOD1 protein, which might affect our interpretation of disease processes. A variant of this strain carries a deletion of the transgene array such that the copy number is dropped to eight to ten mutant SOD1 genes. This ‘deleted’ ‘low-copy’ mouse undergoes a slower course of disease, over many months. Here we have carried out a comprehensive analysis of phenotype, including nerve and muscle physiology and histology, to add to our knowledge of this ‘deleted’ strain and give baseline data for future studies. We find differences in phenotype that arise from genetic background and sex, and we quantify the loss of nerve and muscle function over time. The slowly progressive pathology observed in this mouse strain could provide us with a more appropriate model for studying early-stage pathological processes in ALS and aid the development of therapies for early-stage treatments. PMID:21540242

  1. INaP selective inhibition reverts precocious inter- and motorneurons hyperexcitability in the Sod1-G93R zebrafish ALS model

    PubMed Central

    Benedetti, Lorena; Ghilardi, Anna; Rottoli, Elsa; De Maglie, Marcella; Prosperi, Laura; Perego, Carla; Baruscotti, Mirko; Bucchi, Annalisa; Del Giacco, Luca; Francolini, Maura

    2016-01-01

    The pathogenic role of SOD1 mutations in amyotrophic lateral sclerosis (ALS) was investigated using a zebrafish disease model stably expressing the ALS-linked G93R mutation. In addition to the main pathological features of ALS shown by adult fish, we found remarkably precocious alterations in the development of motor nerve circuitry and embryo behavior, and suggest that these alterations are prompted by interneuron and motor neuron hyperexcitability triggered by anomalies in the persistent pacemaker sodium current INaP. The riluzole-induced modulation of INaP reduced spinal neuron excitability, reverted the behavioral phenotypes and improved the deficits in motor nerve circuitry development, thus shedding new light on the use of riluzole in the management of ALS. Our findings provide a valid phenotype-based tool for unbiased in vivo drug screening that can be used to develop new therapies. PMID:27079797

  2. INaP selective inhibition reverts precocious inter- and motorneurons hyperexcitability in the Sod1-G93R zebrafish ALS model.

    PubMed

    Benedetti, Lorena; Ghilardi, Anna; Rottoli, Elsa; De Maglie, Marcella; Prosperi, Laura; Perego, Carla; Baruscotti, Mirko; Bucchi, Annalisa; Del Giacco, Luca; Francolini, Maura

    2016-01-01

    The pathogenic role of SOD1 mutations in amyotrophic lateral sclerosis (ALS) was investigated using a zebrafish disease model stably expressing the ALS-linked G93R mutation. In addition to the main pathological features of ALS shown by adult fish, we found remarkably precocious alterations in the development of motor nerve circuitry and embryo behavior, and suggest that these alterations are prompted by interneuron and motor neuron hyperexcitability triggered by anomalies in the persistent pacemaker sodium current INaP. The riluzole-induced modulation of INaP reduced spinal neuron excitability, reverted the behavioral phenotypes and improved the deficits in motor nerve circuitry development, thus shedding new light on the use of riluzole in the management of ALS. Our findings provide a valid phenotype-based tool for unbiased in vivo drug screening that can be used to develop new therapies. PMID:27079797

  3. Pilot model hypothesis testing

    NASA Technical Reports Server (NTRS)

    Broussard, J. R.; Berry, P. W.

    1982-01-01

    The aircraft control time history predicted by the optimal control pilot model and actual pilot tracking data obtained from NASA Langley's differential maneuvering simulator (DMS) are analyzed. The analysis is performed using a hypothesis testing scheme modified to allow for changes in the true hypothesis. A finite number of pilot models, each with different hypothesized internal model representations of the aircraft dynamics, are constructed. The hypothesis testing scheme determines the relative probability that each pilot model best matches the DMS data. By observing the changes in probabilities, it is possible to determine when the pilot changes control strategy and which hypothesized pilot model best represent's the pilot's control behavior.

  4. Characterization of the Contribution of Genetic Background and Gender to Disease Progression in the SOD1 G93A Mouse Model of Amyotrophic Lateral Sclerosis: A Meta-Analysis

    PubMed Central

    Pfohl, Stephen R.; Halicek, Martin T.; Mitchell, Cassie S.

    2015-01-01

    Background The SOD1 G93A mouse model of amyotrophic lateral sclerosis (ALS) is the most frequently used model to examine ALS pathophysiology. There is a lack of homogeneity in usage of the SOD1 G93A mouse, including differences in genetic background and gender, which could confound the field’s results. Objective In an analysis of 97 studies, we characterized the ALS progression for the high transgene copy control SOD1 G93A mouse on the basis of disease onset, overall lifespan, and disease duration for male and female mice on the B6SJL and C57BL/6J genetic backgrounds and quantified magnitudes of differences between groups. Methods Mean age at onset, onset assessment measure, disease duration, and overall lifespan data from each study were extracted and statistically modeled as the response of linear regression with the sex and genetic background factored as predictors. Additional examination was performed on differing experimental onset and endpoint assessment measures. Results C57BL/6 background mice show delayed onset of symptoms, increased lifespan, and an extended disease duration compared to their sex-matched B6SJL counterparts. Female B6SJL generally experience extended lifespan and delayed onset compared to their male counterparts, while female mice on the C57BL/6 background show delayed onset but no difference in survival compared to their male counterparts. Finally, different experimental protocols (tremor, rotarod, etc.) for onset determination result in notably different onset means. Conclusions Overall, the observed effect of sex on disease endpoints was smaller than that which can be attributed to the genetic background. The often-reported increase in lifespan for female mice was observed only for mice on the B6SJL background, implicating a strain-dependent effect of sex on disease progression that manifests despite identical mutant SOD1 expression. PMID:26594635

  5. Summary of AH-1G flight vibration data for validation of coupled rotor-fuselage analyses

    NASA Technical Reports Server (NTRS)

    Dompka, R. V.; Cronkhite, J. D.

    1986-01-01

    Under a NASA research program designated DAMVIBS (Design Analysis Methods for VIBrationS), four U. S. helicopter industry participants (Bell Helicopter, Boeing Vertol, McDonnell Douglas Helicopter, and Sikorsky Aircraft) are to apply existing analytical methods for calculating coupled rotor-fuselage vibrations of the AH-1G helicopter for correlation with flight test data from an AH-1G Operational Load Survey (OLS) test program. Bell Helicopter, as the manufacturer of the AH-1G, was asked to provide pertinent rotor data and to collect the OLS flight vibration data needed to perform the correlations. The analytical representation of the fuselage structure is based on a NASTRAN finite element model (FEM) developed by Bell which has been extensively documented and correlated with ground vibration tests.The AH-1G FEM was provided to each of the participants for use in their coupled rotor-fuselage analyses. This report describes the AH-1G OLS flight test program and provides the flight conditions and measured vibration data to be used by each participant in their correlation effort. In addition, the mechanical, structural, inertial and aerodynamic data for the AH-1G two-bladed teetering main rotor system are presented. Furthermore, modifications to the NASTRAN FEM of the fuselage structure that are necessary to make it compatible with the OLS test article are described. The AH-1G OLS flight test data was found to be well documented and provide a sound basis for evaluating currently existing analysis methods used for calculation of coupled rotor-fuselage vibrations.

  6. MODELING THE AMES TEST

    EPA Science Inventory

    Despite the value and widespread use of the Ames test, little attention has been focused on standardizing quantitative methods of analyzing these data. In this paper, a realistic and statistically tractable model is developed for the evaluation of Ames-type data. The model assume...

  7. OCH Strap Model Test

    SciTech Connect

    Weber, K.; /Fermilab

    1987-08-26

    The OCH Model was stacked using the appropriate spacers between each absorber plate. Steel bars measuring 3-inch wide by 1/4-inch thick were welded, using 1/8-inch fillet weld, along all the corner edges, except the outer radius edges. On the outer radius, the straps were bolted to the end plates and to plates 9 and 17. The straps on the outer radius were also set in towards the center by approximately 3-inches. The spacers were then knocked out. Twelve strain gauges were mounted on the model. See figure 1 and the OCH strap Model log book for locations. Each rosette was centered in the gap between two absorber plates. The finite element plate model can predict the primary deformations of the OH module in both the cantilever and crushing modes to within 11% of the measured values. The primary stresses away from the support plate for the cantilever mode can be predicted to within 13% by this model. Near the support plate where large shear stresses exists, ANSYS will overpredict the measured stresses substantially. This is probably due to the models inherent inability to allow for shear stress concentrations at the welds. The same over-prediction was seen in the side straps during the OH crush test comparison and is probably attributable to the high shear force in this mode. The simple finite element plate model will provide suitable model of OH module stiffness for use in the analysis of the module assembly. The calculation of shear stresses can be improved by applying the ANSYS calculated inter-element forces to traditional weld strength calculations

  8. Solubility of chlorargyrite (AgCl(cr./l.)) in water: New experimental data and a predictive model valid for a wide range of temperatures (273-873 K) and water densities (0.01-1 g·cm-3)

    NASA Astrophysics Data System (ADS)

    Akinfiev, Nikolay N.; Zotov, Alexander V.

    2016-04-01

    The solubility of chlorargyrite, AgCl(cr./l.), in pure water at 623, 673 and 753 (±2) K as a function of pressure in a wide range aqueous densities (0.01-0.7 g·cm-3) was determined using various experimental approaches. Combined theoretical quantum chemistry simulations of Ag speciation and structure with a recently developed equation of state (EoS) for aqueous neutral species (Akinfiev and Diamond, 2003) were applied to describe published and newly made AgCl(cr./l.) solubility measurements in water. The use of the employed EoS for AgCl(H2O)(aq) cluster is found out to provide a good description of the whole set of experimental measurements in a wide range of temperatures (273-753 K), water densities (0.01-0.7 g·cm-3), and pressures of 0.1-100 MPa. Also, the proposed AgCl(H2O)(aq) thermodynamic description is proved to be valid for a dense aqueous fluid (0.7-1 g·cm-3) at 273-623 K and saturation water pressure. Although silver obviously shows greater affinity to dense aqueous fluid, AgCl hydration in the vapour phase is demonstrated to be also significant. A model extrapolation to magmatic conditions predicts an appreciable silver content even in low density fluids, thus supporting the hypothesis of metal transport with vapour.

  9. The Overexpression of TDP-43 Protein in the Neuron and Oligodendrocyte Cells Causes the Progressive Motor Neuron Degeneration in the SOD1 G93A Transgenic Mouse Model of Amyotrophic Lateral Sclerosis.

    PubMed

    Lu, Yi; Tang, Chunyan; Zhu, Lei; Li, Jiao; Liang, Huiting; Zhang, Jie; Xu, Renshi

    2016-01-01

    The recent investigation suggested that the TDP-43 protein was closely related to the motor neuron degeneration in amyotrophic lateral sclerosis (ALS), but the pathogenesis contributed to motor neuron degeneration largely remained unknown. Therefore, we detected the alteration of TDP-43 expression and distribution in the adult spinal cord of the SOD1 G93A transgenic mouse model for searching the possible pathogenesis of ALS. We examined the TDP-43 expression and distribution in the different anatomic regions, segments and neural cells in the adult spinal cord at the different stages of the SOD1 wild-type and G93A transgenic model by the fluorescent immunohistochemical technology. We revealed that the amount of TDP-43 positive cell was cervical>lumbar>thoracic segment, that in the ventral horn was more than that in the dorsal horn, a few of TDP-43 protein sparsely expressed and distributed in the other regions, the TDP-43 protein weren't detected in the white matter and the central canal. The TDP-43 protein was mostly expressed and distributed in the nuclear of neuron cells and the cytoplasm of oligodendrocyte cells of the gray matter surrounding the central canal of spinal cord by the granular shape in the SOD1 wild-type and G93A transgenic mice. The amount of TDP-43 positive cell significantly increased at the onset and progression stages of ALS following with the increase of neuron death in spinal cord, particularly in the ventral horn of cervical segment at the progression stage. Our results suggested that the overexpression of TDP-43 protein in the neuron and oligodendrocyte cell causes the progressive motor neuron degeneration in the ALS-like mouse model. PMID:27570488

  10. The Overexpression of TDP-43 Protein in the Neuron and Oligodendrocyte Cells Causes the Progressive Motor Neuron Degeneration in the SOD1 G93A Transgenic Mouse Model of Amyotrophic Lateral Sclerosis

    PubMed Central

    Lu, Yi; Tang, Chunyan; Zhu, Lei; Li, Jiao; Liang, Huiting; Zhang, Jie; Xu, Renshi

    2016-01-01

    The recent investigation suggested that the TDP-43 protein was closely related to the motor neuron degeneration in amyotrophic lateral sclerosis (ALS), but the pathogenesis contributed to motor neuron degeneration largely remained unknown. Therefore, we detected the alteration of TDP-43 expression and distribution in the adult spinal cord of the SOD1 G93A transgenic mouse model for searching the possible pathogenesis of ALS. We examined the TDP-43 expression and distribution in the different anatomic regions, segments and neural cells in the adult spinal cord at the different stages of the SOD1 wild-type and G93A transgenic model by the fluorescent immunohistochemical technology. We revealed that the amount of TDP-43 positive cell was cervical>lumbar>thoracic segment, that in the ventral horn was more than that in the dorsal horn, a few of TDP-43 protein sparsely expressed and distributed in the other regions, the TDP-43 protein weren't detected in the white matter and the central canal. The TDP-43 protein was mostly expressed and distributed in the nuclear of neuron cells and the cytoplasm of oligodendrocyte cells of the gray matter surrounding the central canal of spinal cord by the granular shape in the SOD1 wild-type and G93A transgenic mice. The amount of TDP-43 positive cell significantly increased at the onset and progression stages of ALS following with the increase of neuron death in spinal cord, particularly in the ventral horn of cervical segment at the progression stage. Our results suggested that the overexpression of TDP-43 protein in the neuron and oligodendrocyte cell causes the progressive motor neuron degeneration in the ALS-like mouse model. PMID:27570488

  11. Marked changes in dendritic structure and spine density precede significant neuronal death in vulnerable cortical pyramidal neuron populations in the SOD1(G93A) mouse model of amyotrophic lateral sclerosis.

    PubMed

    Fogarty, Matthew J; Mu, Erica W H; Noakes, Peter G; Lavidis, Nickolas A; Bellingham, Mark C

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is characterised by the death of upper (corticospinal) and lower motor neurons (MNs) with progressive muscle weakness. This incurable disease is clinically heterogeneous and its aetiology remains unknown. Increased excitability of corticospinal MNs has been observed prior to symptoms in human and rodent studies. Increased excitability has been correlated with structural changes in neuronal dendritic arbors and spines for decades. Here, using a modified Golgi-Cox staining method, we have made the first longitudinal study examining the dendrites of pyramidal neurons from the motor cortex, medial pre-frontal cortex, somatosensory cortex and entorhinal cortex of hSOD1(G93A) (SOD1) mice compared to wild-type (WT) littermate controls at postnatal (P) days 8-15, 28-35, 65-75 and 120. Progressive decreases in dendritic length and spine density commencing at pre-symptomatic ages (P8-15 or P28-35) were observed in layer V pyramidal neurons within the motor cortex and medial pre-frontal cortex of SOD1 mice compared to WT mice. Spine loss without concurrent dendritic pathology was present in the pyramidal neurons of the somatosensory cortex from disease-onset (P65-75). Our results from the SOD1 model suggest that dendritic and dendritic spine changes foreshadow and underpin the neuromotor phenotypes present in ALS and may contribute to the varied cognitive, executive function and extra-motor symptoms commonly seen in ALS patients. Determining if these phenomena are compensatory or maladaptive may help explain differential susceptibility of neurons to degeneration in ALS. PMID:27488828

  12. Test Administration Models

    ERIC Educational Resources Information Center

    Becker, Kirk A.; Bergstrom, Betty A.

    2013-01-01

    The need for increased exam security, improved test formats, more flexible scheduling, better measurement, and more efficient administrative processes has caused testing agencies to consider converting the administration of their exams from paper-and-pencil to computer-based testing (CBT). Many decisions must be made in order to provide an optimal…

  13. Expression of the ALS-causing variant hSOD1G93A leads to an impaired integrity and altered regulation of claudin-5 expression in an in vitro blood–spinal cord barrier model

    PubMed Central

    Meister, Sabrina; Storck, Steffen E; Hameister, Erik; Behl, Christian; Weggen, Sascha; Clement, Albrecht M; Pietrzik, Claus U

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive paralysis due to the loss of primary and secondary motor neurons. Mutations in the Cu/Zn-superoxide dismutase (SOD1) gene are associated with familial ALS and to date numerous hypotheses for ALS pathology exist including impairment of the blood–spinal cord barrier. In transgenic mice carrying mutated SOD1 genes, a disrupted blood–spinal cord barrier as well as decreased levels of tight junction (TJ) proteins ZO-1, occludin, and claudin-5 were detected. Here, we examined TJ protein levels and barrier function of primary blood–spinal cord barrier endothelial cells of presymptomatic hSOD1G93A mice and bEnd.3 cells stably expressing hSOD1G93A. In both cellular systems, we observed reduced claudin-5 levels and a decreased transendothelial resistance (TER) as well as an increased apparent permeability. Analysis of the β-catenin/AKT/forkhead box protein O1 (FoxO1) pathway and the FoxO1-regulated activity of the claudin-5 promoter revealed a repression of the claudin-5 gene expression in hSOD1G93A cells, which was depended on the phosphorylation status of FoxO1. These results strongly indicate that mutated SOD1 affects the expression and localization of TJ proteins leading to impaired integrity and breakdown of the blood–spinal cord barrier. PMID:25853911

  14. UPWT check standard model test

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Installation of the check standard model in test section 2 of the Unitary Plan Wind Tunnel (UPWT). Testing was conducted as part of a Data Quality Control assessment in the Research Facilities Branch/Aerodynamics Aerothermodynamics Acoustics Competency.

  15. Testing bow shock models

    NASA Astrophysics Data System (ADS)

    Alrefay, Thamer; Meziane, Karim; Hamza, A. M.

    2016-07-01

    Space plasmas studies of bow shock dynamics, given the fundamental transport role and impact natural transition boundaries, have continued to attract much interest. With the overwhelming availability of data collected by various space science missions, several empirical models have been put forward to account for the location of the Earth's bow shock. Various solar wind and IMF measured parameters are used to constrain the proposed models published in the literature. For each of these empirical models, the bow shock nose velocity, at the standoff distance, is computed; each of these velocities is then compared with the observed shock speed as determined from a multipoint measurement provided by the Cluster quartet. The present study reveals to what extent the model parameters used are significant and determinant, and suggests that some empirical models are more accurate than others are.

  16. Modeling cylinder test

    SciTech Connect

    Tang, P.K.; Scannapieco, A.J.

    1996-05-01

    The dynamic behavior of a copper tube containing high explosive PBX 9502 is studied. The detonation of the explosive propagating along the axis drives the copper tube radially outward. A multi-process reactive model is used to simulate the explosive burn behavior in an Eulerian hydrodynamic code. In addition, an adaptive mesh refinement technique is featured in controlling the computational mesh size as the detonation wave moves in and out of a region. Comparison with experiments is made to show the capability of the new hydrocode. {copyright} {ital 1996 American Institute of Physics.}

  17. Modeling cylinder test

    SciTech Connect

    Tang, P.K.; Scannapieco, A.J.

    1995-09-01

    The dynamic behavior of a copper tube containing high explosive PBX 9502 is studied. The detonation of the explosive propagating along the axis drives the copper tube radially outward. A multi-process reactive model is used to simulate the explosive burn behavior in an Eulerian hydrodynamic code. In addition,an adaptive mesh refinement technique is featured in controlling the computational mesh size as the detonation wave moves in and out of a region. Comparison with experiments is made to show the capability of the new hydrocode.

  18. Testing the model for testing competency.

    PubMed

    Keating, Sarah B; Rutledge, Dana N; Sargent, Arlene; Walker, Polly

    2003-05-01

    The pilot study to demonstrate the utility of the CBRDM in the practice setting was successful. Using a matrix evaluation tool based on the model's competencies, evaluators were able to observe specific performance behaviors of senior nursing students and new graduates at either the novice or competent levels. The study faced the usual perils of pilot studies, including small sample size, a limited number of items from the total CBRDM, restricted financial resources, inexperienced researchers, unexpected barriers, and untested evaluation tools. It was understood from the beginning of the study that the research would be based on a program evaluation model, analyzing both processes and outcomes. However, the meager data findings led to the desire to continue to study use of the model for practice setting job expectations, career planning for nurses, and curriculum development for educators. Although the California Strategic Planning Committee for Nursing no longer has funding, we hope that others interested in role differentiation issues will take the results of this study and test the model in other practice settings. Its ability to measure higher levels of competency as well as novice and competent should be studied, i.e., proficient, expert, and advanced practice. The CBRDM may be useful in evaluating student and nurse performance, defining role expectations, and identifying the preparation necessary for the roles. The initial findings related to the two functions as leader and teacher in the care provider and care coordinator roles led to much discussion about helping students and nurses develop competence. Additional discussion focused on the roles as they apply to settings such as critical care or primary health care. The model is useful for all of nursing as it continues to define its levels of practice and their relationship to on-the-job performance, curriculum development, and career planning. PMID:12747069

  19. Frequentist tests for Bayesian models

    NASA Astrophysics Data System (ADS)

    Lucy, L. B.

    2016-04-01

    Analogues of the frequentist chi-square and F tests are proposed for testing goodness-of-fit and consistency for Bayesian models. Simple examples exhibit these tests' detection of inconsistency between consecutive experiments with identical parameters, when the first experiment provides the prior for the second. In a related analysis, a quantitative measure is derived for judging the degree of tension between two different experiments with partially overlapping parameter vectors.

  20. Investigation of difficult component effects on FEM vibration prediction for the AH-1G helicopter

    NASA Technical Reports Server (NTRS)

    Dompka, Robert V.

    1988-01-01

    Under the NASA-sponsored Design Analysis Methods for Vibrations program, a series of ground vibration tests and NASTRAN finite element model correlations were conducted on the Bell AH-1G helicopter gunship to investigate the effects of difficult components on the vibration response of the airframe. Secondary structure and damping were found to have significant effects on the frequency response of the airframe above 15 Hz. The nonlinear effects of thrust stiffening and elastomeric mounts on the low-frequency pylon modes below the main rotor were also significant.

  1. Analytical models of slug tests

    SciTech Connect

    Karasaki, K.; Long, J.C.S.; Witherspoon, P.A.

    1988-01-01

    In the present paper, attempts are made to develop solutions to various models of slug tests that may be applicable in analyzing the results of such tests where existing solutions are inadequate. Various geometries that may be encountered in heterogeneous systems such as fractured rocks are considered. Solutions are presented for linear flow, radial flow with boundaries, two layer, and concentric composite models with different flow geometries between the inner and outer region. Solutions are obtained in Laplace space and inverted back to real space numerically. Type curves are presented for each solution. Analyses of the type curves and derivative response curves reveal that many curves have unique shapes only for certain combination of the flow parameters and the distance. Other sets of type curves are similar in shape, although log-log plots and derivative plots may emphasize some features that may not be apparent in semilog plots. These results show that slug tests suffer problems of nonuniqueness to a greater extent than other well tests.

  2. Viking Mars lander 1975 dynamic test model/orbiter developmental test model forced vibration test

    NASA Technical Reports Server (NTRS)

    Fortenberry, J.; Brownlee, G. R.

    1974-01-01

    The Viking Mars Lander 1975 dynamic test model and orbiter developmental test model were subjected to forced vibration sine tests. Flight acceptance (FA) and type approval (TA) test levels were applied to the spacecraft structure in a longitudinal test configuration using a 133,440-N (30,000-lb) force shaker. Testing in the two lateral axes (X, Y) was performed at lower levels using four 667-N (150-lb) force shakers. Forced vibration qualification (TA) test levels were successfully imposed on the spacecraft at frequencies down to 10 Hz. Measured responses showed the same character as analytical predictions, and correlation was reasonably good. Because of control system test tolerances, orbiter primary structure generally did not reach the design load limits attained in earlier static testing. A post-test examination of critical orbiter structure disclosed no apparent damage to the structure as a result of the test environment.

  3. Genetic Biomarkers for ALS Disease in Transgenic SOD1G93A Mice

    PubMed Central

    Calvo, Ana C.; Manzano, Raquel; Atencia-Cibreiro, Gabriela; Oliván, Sara; Muñoz, María J.; Zaragoza, Pilar; Cordero-Vázquez, Pilar; Esteban-Pérez, Jesús; García-Redondo, Alberto; Osta, Rosario

    2012-01-01

    The pathophysiological mechanisms of both familial and sporadic Amyotrophic Lateral Sclerosis (ALS) are unknown, although growing evidence suggests that skeletal muscle tissue is a primary target of ALS toxicity. Skeletal muscle biopsies were performed on transgenic SOD1G93A mice, a mouse model of ALS, to determine genetic biomarkers of disease longevity. Mice were anesthetized with isoflurane, and three biopsy samples were obtained per animal at the three main stages of the disease. Transcriptional expression levels of seventeen genes, Ankrd1, Calm1, Col19a1, Fbxo32, Gsr, Impa1, Mef2c, Mt2, Myf5, Myod1, Myog, Nnt, Nogo A, Pax7, Rrad, Sln and Snx10, were tested in each muscle biopsy sample. Total RNA was extracted using TRIzol Reagent according to the manufacturer's protocol, and variations in gene expression were assayed by real-time PCR for all of the samples. The Pearson correlation coefficient was used to determine the linear correlation between transcriptional expression levels throughout disease progression and longevity. Consistent with the results obtained from total skeletal muscle of transgenic SOD1G93A mice and 74-day-old denervated mice, five genes (Mef2c, Gsr, Col19a1, Calm1 and Snx10) could be considered potential genetic biomarkers of longevity in transgenic SOD1G93A mice. These results are important because they may lead to the exploration of previously unexamined tissues in the search for new disease biomarkers and even to the application of these findings in human studies. PMID:22412900

  4. Remote control missile model test

    NASA Technical Reports Server (NTRS)

    Allen, Jerry M.; Shaw, David S.; Sawyer, Wallace C.

    1989-01-01

    An extremely large, systematic, axisymmetric body/tail fin data base was gathered through tests of an innovative missile model design which is described herein. These data were originally obtained for incorporation into a missile aerodynamics code based on engineering methods (Program MISSILE3), but can also be used as diagnostic test cases for developing computational methods because of the individual-fin data included in the data base. Detailed analysis of four sample cases from these data are presented to illustrate interesting individual-fin force and moment trends. These samples quantitatively show how bow shock, fin orientation, fin deflection, and body vortices can produce strong, unusual, and computationally challenging effects on individual fin loads. Comparisons between these data and calculations from the SWINT Euler code are also presented.

  5. Testing Strategies for Model-Based Development

    NASA Technical Reports Server (NTRS)

    Heimdahl, Mats P. E.; Whalen, Mike; Rajan, Ajitha; Miller, Steven P.

    2006-01-01

    This report presents an approach for testing artifacts generated in a model-based development process. This approach divides the traditional testing process into two parts: requirements-based testing (validation testing) which determines whether the model implements the high-level requirements and model-based testing (conformance testing) which determines whether the code generated from a model is behaviorally equivalent to the model. The goals of the two processes differ significantly and this report explores suitable testing metrics and automation strategies for each. To support requirements-based testing, we define novel objective requirements coverage metrics similar to existing specification and code coverage metrics. For model-based testing, we briefly describe automation strategies and examine the fault-finding capability of different structural coverage metrics using tests automatically generated from the model.

  6. Ground testing and model updating for flexible space structures

    NASA Astrophysics Data System (ADS)

    Crawford, James Mackenzie

    2001-07-01

    Aspects of the ground testing portion of the Dynamics Identification and Control Experiment (DICE) are explored. DICE is a proposed International Space Station (ISS) experiment whose goal is to investigate System Identification (SI) and attitude and shape control using a small free flying spacecraft, inside an ISS experimental module, that features a rigid central bus controlled using reaction wheels and an array of flexible appendages or 'ribs' fitted with control moment gyroscope end-effectors. Extensive testing prior to launch is required before a high quality 0-g math model can be predicted and the benefits of on-orbit system identification evaluated. To this end, two technologies are developed in this thesis. The first is a passive mechanical suspension system that allows dynamical ground testing in the fully deployed configuration, providing support for the DICE bodies, a zero deflection at-rest state, and high compliance for all degrees of freedom. Based on concepts from the literature combined with innovative design improvements, a prototype is built and evaluated, showing excellent performance in local mode suppression and damping. It is then successfully used in tests with one of the prototype DICE ribs. The second technology is a Model Updating (MU) technique that uses experimental data to fine tune the 1-g math model while retaining the ability to generalize the model to the 0-g case. The technique optimizes the parameters in the nonlinear model by making direct use of time history data from multiple ground test configurations and the weighted uncertainties of the parameters, thereby maximizing the validity of the extrapolated on-orbit model. Although more computationally intensive than other SI methods, the MU technique allows nonlinear models to be updated, retains physically meaningful model parameters and state-space (a requirement for the 0-g model prediction), and when demonstrated with real experimental data performs just as well in reducing

  7. Coupled rotor/fuselage dynamic analysis of the AH-1G helicopter and correlation with flight vibrations data

    NASA Technical Reports Server (NTRS)

    Corrigan, J. C.; Cronkhite, J. D.; Dompka, R. V.; Perry, K. S.; Rogers, J. P.; Sadler, S. G.

    1989-01-01

    Under a research program designated Design Analysis Methods for VIBrationS (DAMVIBS), existing analytical methods are used for calculating coupled rotor-fuselage vibrations of the AH-1G helicopter for correlation with flight test data from an AH-1G Operational Load Survey (OLS) test program. The analytical representation of the fuselage structure is based on a NASTRAN finite element model (FEM), which has been developed, extensively documented, and correlated with ground vibration test. One procedure that was used for predicting coupled rotor-fuselage vibrations using the advanced Rotorcraft Flight Simulation Program C81 and NASTRAN is summarized. Detailed descriptions of the analytical formulation of rotor dynamics equations, fuselage dynamic equations, coupling between the rotor and fuselage, and solutions to the total system of equations in C81 are included. Analytical predictions of hub shears for main rotor harmonics 2p, 4p, and 6p generated by C81 are used in conjunction with 2p OLS measured control loads and a 2p lateral tail rotor gearbox force, representing downwash impingement on the vertical fin, to excite the NASTRAN model. NASTRAN is then used to correlate with measured OLS flight test vibrations. Blade load comparisons predicted by C81 showed good agreement. In general, the fuselage vibration correlations show good agreement between anslysis and test in vibration response through 15 to 20 Hz.

  8. Vaccine potential of recombinant cathepsinL1G against Fasciola gigantica in mice.

    PubMed

    Changklungmoa, Narin; Phoinok, Natthacha; Yencham, Chonthicha; Sobhon, Prasert; Kueakhai, Pornanan

    2016-08-15

    In this study, we characterized and investigated the vaccine potential of FgCatL1G against Fasciola gigantica infection in mice. Recombinant mature FgCatL1G (rmFgCatL1G) was expressed in Escherichia coli BL21. The vaccination was performed in Imprinting Control Region (ICR) mice (n=10) by subcutaneous injection with 50μg of rmFgCatL1G combined with Freund's adjuvant. Two weeks after the second boost, mice were infected with 15 metacercariae by the oral route. The percents of protection of rmFgCatL1G vaccine were estimated to be 56.5% and 58.3% when compared with non vaccinated-infected and adjuvant-infected controls, respectively. Antibodies in the immune sera of vaccinated mice were shown by immunoblot to react with the native FgCatL1s in the extract of all stages of parasites and rmFgCatL1H, recombinant pro - FgCatL1 (rpFgCatL1). By immunohistochemistry, the immune sera also reacted with FgCatL1s in the caecal epithelial cells of the parasites. The levels of IgG1 and IgG2a in the immune sera, which are indicative of Th2 and Th1 immune responses, were also increased with IgG1 predominating. The levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) in rmFgCatL1G-immunized group showed no significant difference from the control groups, but pathological lesions of livers in rmFgCatL1G-immunized group showed significant decrease when compared to the control groups. This study indicates that rmFgCatL1G has a vaccine potential against F. gigantica in mice, and this potential will be tested in larger livestock animals. PMID:27514897

  9. Testing Linear Models for Ability Parameters in Item Response Models

    ERIC Educational Resources Information Center

    Glas, Cees A. W.; Hendrawan, Irene

    2005-01-01

    Methods for testing hypotheses concerning the regression parameters in linear models for the latent person parameters in item response models are presented. Three tests are outlined: A likelihood ratio test, a Lagrange multiplier test and a Wald test. The tests are derived in a marginal maximum likelihood framework. They are explicitly formulated…

  10. Outer planet probe engineering model structural tests

    NASA Technical Reports Server (NTRS)

    Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

    1977-01-01

    A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

  11. 46 CFR 154.449 - Model test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Model test. 154.449 Section 154.449 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF... § 154.449 Model test. The following analyzed data of a model test of structural elements for...

  12. 46 CFR 154.431 - Model test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Model test. 154.431 Section 154.431 Shipping COAST GUARD... Model test. (a) The primary and secondary barrier of a membrane tank, including the corners and joints...(c). (b) Analyzed data of a model test for the primary and secondary barrier of the membrane...

  13. 46 CFR 154.449 - Model test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Model test. 154.449 Section 154.449 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF... § 154.449 Model test. The following analyzed data of a model test of structural elements for...

  14. 46 CFR 154.431 - Model test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Model test. 154.431 Section 154.431 Shipping COAST GUARD... Model test. (a) The primary and secondary barrier of a membrane tank, including the corners and joints...(c). (b) Analyzed data of a model test for the primary and secondary barrier of the membrane...

  15. 46 CFR 154.449 - Model test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Model test. 154.449 Section 154.449 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF... § 154.449 Model test. The following analyzed data of a model test of structural elements for...

  16. 46 CFR 154.431 - Model test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Model test. 154.431 Section 154.431 Shipping COAST GUARD... Model test. (a) The primary and secondary barrier of a membrane tank, including the corners and joints...(c). (b) Analyzed data of a model test for the primary and secondary barrier of the membrane...

  17. 46 CFR 154.449 - Model test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Model test. 154.449 Section 154.449 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF... § 154.449 Model test. The following analyzed data of a model test of structural elements for...

  18. 46 CFR 154.431 - Model test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Model test. 154.431 Section 154.431 Shipping COAST GUARD... Model test. (a) The primary and secondary barrier of a membrane tank, including the corners and joints...(c). (b) Analyzed data of a model test for the primary and secondary barrier of the membrane...

  19. Caspase 6 has a protective role in SOD1(G93A) transgenic mice.

    PubMed

    Hogg, Marion C; Mitchem, Mollie R; König, Hans-Georg; Prehn, Jochen H M

    2016-06-01

    In amyotrophic lateral sclerosis (ALS), it has been suggested that the process of neurodegeneration starts at the neuromuscular junction and is propagated back along axons towards motor neurons. Caspase-dependent pathways are well established as a cause of motor neuron death, and recent work in other disease models indicated a role for caspase 6 in axonal degeneration. Therefore we hypothesised that caspase 6 may be involved in motor neuron death in ALS. To investigate the role of caspase 6 in ALS we profiled protein levels of caspase-6 throughout disease progression in the ALS mouse model SOD1(G93A); this did not reveal differences in caspase 6 levels during disease. To investigate the role of caspase 6 further we generated a colony with SOD1(G93A) transgenic mice lacking caspase 6. Analysis of the transgenic SOD1(G93A); Casp6(-/-) revealed an exacerbated phenotype with motor dysfunction occurring earlier and a significantly shortened lifespan when compared to transgenic SOD1(G93A); Casp6(+/+) mice. Immunofluorescence analysis of the neuromuscular junction revealed no obvious difference between caspase 6(+/+) and caspase 6(-/-) in non-transgenic mice, while the SOD1(G93A) transgenic mice showed severe degeneration compared to non-transgenic mice in both genotypes. Our data indicate that caspase-6 does not exacerbate ALS pathogenesis, but may have a protective role. PMID:26976329

  20. Testing Galactic Cosmic Ray Models

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.

    2010-01-01

    Models of the Galactic Cosmic Ray Environment are used for designing and planning space missions. The exising models will be reviewed. Spectral representations from these models will be compared with measurements of galactic cosmic ray spectra made on balloon flights and satellite flights over a period of more than 50 years.

  1. Testing Galactic Cosmic Ray Models

    NASA Technical Reports Server (NTRS)

    Adams, James H., Jr.

    2009-01-01

    Models of the Galactic Cosmic Ray Environment are used for designing and planning space missions. The existing models will be reviewed. Spectral representations from these models will be compared with measurements of galactic cosmic ray spectra made on balloon flights and satellite flights over a period of more than 50 years.

  2. Testing of constitutive models in LAME.

    SciTech Connect

    Hammerand, Daniel Carl; Scherzinger, William Mark

    2007-09-01

    Constitutive models for computational solid mechanics codes are in LAME--the Library of Advanced Materials for Engineering. These models describe complex material behavior and are used in our finite deformation solid mechanics codes. To ensure the correct implementation of these models, regression tests have been created for constitutive models in LAME. A selection of these tests is documented here. Constitutive models are an important part of any solid mechanics code. If an analysis code is meant to provide accurate results, the constitutive models that describe the material behavior need to be implemented correctly. Ensuring the correct implementation of constitutive models is the goal of a testing procedure that is used with the Library of Advanced Materials for Engineering (LAME) (see [1] and [2]). A test suite for constitutive models can serve three purposes. First, the test problems provide the constitutive model developer a means to test the model implementation. This is an activity that is always done by any responsible constitutive model developer. Retaining the test problem in a repository where the problem can be run periodically is an excellent means of ensuring that the model continues to behave correctly. A second purpose of a test suite for constitutive models is that it gives application code developers confidence that the constitutive models work correctly. This is extremely important since any analyst that uses an application code for an engineering analysis will associate a constitutive model in LAME with the application code, not LAME. Therefore, ensuring the correct implementation of constitutive models is essential for application code teams. A third purpose of a constitutive model test suite is that it provides analysts with example problems that they can look at to understand the behavior of a specific model. Since the choice of a constitutive model, and the properties that are used in that model, have an enormous effect on the results of an

  3. Preliminary characterisation of new glass reference materials (GSA-1G, GSC-1G, GSD-1G and GSE-1G) by laser ablation-inductively coupled plasma-mass spectrometry using 193 nm, 213 nm and 266 nm wavelengths

    USGS Publications Warehouse

    Guillong, M.; Hametner, K.; Reusser, E.; Wilson, S.A.; Gunther, D.

    2005-01-01

    New glass reference materials GSA-1G, GSC-1G, GSD-1G and GSE-1G have been characterised using a prototype solid state laser ablation system capable of producing wavelengths of 193 nm, 213 nm and 266 nm. This system allowed comparison of the effects of different laser wavelengths under nearly identical ablation and ICP operating conditions. The wavelengths 213 nm and 266 nm were also used at higher energy densities to evaluate the influence of energy density on quantitative analysis. In addition, the glass reference materials were analysed using commercially available 266 nm Nd:YAG and 193 nm ArF excimer lasers. Laser ablation analysis was carried out using both single spot and scanning mode ablation. Using laser ablation ICP-MS, concentrations of fifty-eight elements were determined with external calibration to the NIST SRM 610 glass reference material. Instead of applying the more common internal standardisation procedure, the total concentration of all element oxide concentrations was normalised to 100%. Major element concentrations were compared with those determined by electron microprobe. In addition to NIST SRM 610 for external calibration, USGS BCR-2G was used as a more closely matrix-matched reference material in order to compare the effect of matrix-matched and non matrix-matched calibration on quantitative analysis. The results show that the various laser wavelengths and energy densities applied produced similar results, with the exception of scanning mode ablation at 266 nm without matrix-matched calibration where deviations up to 60% from the average were found. However, results acquired using a scanning mode with a matrix-matched calibration agreed with results obtained by spot analysis. The increased abundance of large particles produced when using a scanning ablation mode with NIST SRM 610, is responsible for elemental fractionation effects caused by incomplete vaporisation of large particles in the ICP.

  4. Computerized Adaptive Testing under Nonparametric IRT Models

    ERIC Educational Resources Information Center

    Xu, Xueli; Douglas, Jeff

    2006-01-01

    Nonparametric item response models have been developed as alternatives to the relatively inflexible parametric item response models. An open question is whether it is possible and practical to administer computerized adaptive testing with nonparametric models. This paper explores the possibility of computerized adaptive testing when using…

  5. GEOCHEMICAL TESTING AND MODEL DEVELOPMENT - RESIDUAL TANK WASTE TEST PLAN

    SciTech Connect

    CANTRELL KJ; CONNELLY MP

    2010-03-09

    This Test Plan describes the testing and chemical analyses release rate studies on tank residual samples collected following the retrieval of waste from the tank. This work will provide the data required to develop a contaminant release model for the tank residuals from both sludge and salt cake single-shell tanks. The data are intended for use in the long-term performance assessment and conceptual model development.

  6. Test of the antiorthostatic suspension model on mice - Effects on the inflammatory cell response

    NASA Technical Reports Server (NTRS)

    Rosenkrans, Charles F., Jr.; Chapes, Stephen K.; Fleming, Sherry D.

    1990-01-01

    The antiorthostatic suspension model was tested for use as a 1G model to study the effects of factors that will be encountered during space travel on inflammation. No differences were found in inflammatory cells induced in antiorthostatically suspended mice. However, the superoxide response (used for oxidative killing of bacteria such as S. aureus) was impaired in antiorthostatically oriented mice compared to control mice. Elevated corticosterone levels were found in antiorthostatically suspended mice, indicating that stress may be a factor in the model. If the stress factor of the model correlates with the physiological stress of space flight, antiorthostatic suspension may be an acceptable model for studying inflammatory responses in mice.

  7. Model test optimization using the virtual environment for test optimization

    SciTech Connect

    Klenke, S.E.; Reese, G.M.; Schoof, L.A.; Shierling, C.

    1995-11-01

    We present a software environment integrating analysis and test-based models to support optimal modal test design through a Virtual Environment for Test Optimization (VETO). The VETO assists analysis and test engineers to maximize the value of each modal test. It is particularly advantageous for structural dynamics model reconciliation applications. The VETO enables an engineer to interact with a finite element model of a test object to optimally place sensors and exciters and to investigate the selection of data acquisition parameters needed to conduct a complete modal survey. Additionally, the user can evaluate the use of different types of instrumentation such as filters, amplifiers and transducers for which models are available in the VETO. The dynamic response of most of the virtual instruments (including the device under test) are modeled in the state space domain. Design of modal excitation levels and appropriate test instrumentation are facilitated by the VETO`s ability to simulate such features as unmeasured external inputs, A/D quantization effects, and electronic noise. Measures of the quality of the experimental design, including the Modal Assurance Criterion, and the Normal Mode Indicator Function are available. The VETO also integrates tools such as Effective Independence and minamac to assist in selection of optimal sensor locations. The software is designed about three distinct modules: (1) a main controller and GUI written in C++, (2) a visualization model, taken from FEAVR, running under AVS, and (3) a state space model and time integration module built in SIMULINK. These modules are designed to run as separate processes on interconnected machines.

  8. Results of steel containment vessel model test

    SciTech Connect

    Luk, V.K.; Ludwigsen, J.S.; Hessheimer, M.F.; Komine, Kuniaki; Matsumoto, Tomoyuki; Costello, J.F.

    1998-05-01

    A series of static overpressurization tests of scale models of nuclear containment structures is being conducted by Sandia National Laboratories for the Nuclear Power Engineering Corporation of Japan and the US Nuclear Regulatory Commission. Two tests are being conducted: (1) a test of a model of a steel containment vessel (SCV) and (2) a test of a model of a prestressed concrete containment vessel (PCCV). This paper summarizes the conduct of the high pressure pneumatic test of the SCV model and the results of that test. Results of this test are summarized and are compared with pretest predictions performed by the sponsoring organizations and others who participated in a blind pretest prediction effort. Questions raised by this comparison are identified and plans for posttest analysis are discussed.

  9. Liquid propulsion turbomachinery model testing

    NASA Astrophysics Data System (ADS)

    1992-07-01

    The various testing techniques utilized to evaluate the flow environment of the Space Shuttle Main Engine (SSME) hot gas manifold are presented. Through a NASA experimental research program, engineers are trying to minimize the fluid dynamic entities and their adverse effects on the SSME. It has been possible to evaluate the flow field and performance changes between various configurations of the manifold, and to examine the effects on the flow field of changing replaceable components of the SSME.

  10. Study of paracetamol 1-g oral solution bioavailability.

    PubMed

    Farre, M; Roset, P N; Abanades, S; Menoyo, E; Alvarez, Y; Rovira, M; Baena, A

    2008-01-01

    The aim of this work was to assess paracetamol bioavailability after administering 1 g in oral solution. Eighteen healthy volunteers were selected for this open-label study. A total of 15.4 ml of Gelocatil Oral Solution (Laboratorios Gelos, S.L.), corresponding to 1 g of paracetamol, were administered to fasting subjects. Blood samples were collected at 0 min, 10 min, 20 min, 30 min, 45 min, 1 h, 1.5 h, 2 h, 3 h, 4 h, 6 h, 8 h, 10 h and 12 h. Paracetamol plasma concentrations were determined by reverse-phase high-performance liquid chromatography. The study was conducted without deviations from protocol. Pharmacokinetic data from 18 subjects were allowed for estimating fast and high-paracetamol bioavailability: t(max) 20 min (10-45) [median (range)], C(max) 24. 3 mg/l (6.5) [mean (standard deviation)], AUC(0-t) 64.0 mg h/l (16.1) and AUC(0-00) 68.1 mg h/l (17.9). These results are comparable to those described for Gelocatil Oral Solution given at a 650 mg dose and for immediate release Gelocatil 650 mg tablets. Absorption speed was very fast, similar to that described for other oral-solution formulations, which provides an immediate onset of pain and fever relief. The results of this study show suitable bioavailability for 1 g Gelocatil Oral Solution, with fast-absorption speed that provides an immediate onset of pain and fever relief. PMID:18389096

  11. Linear Logistic Test Modeling with R

    ERIC Educational Resources Information Center

    Baghaei, Purya; Kubinger, Klaus D.

    2015-01-01

    The present paper gives a general introduction to the linear logistic test model (Fischer, 1973), an extension of the Rasch model with linear constraints on item parameters, along with eRm (an R package to estimate different types of Rasch models; Mair, Hatzinger, & Mair, 2014) functions to estimate the model and interpret its parameters. The…

  12. Used Fuel Testing Transportation Model

    SciTech Connect

    Ross, Steven B.; Best, Ralph E.; Maheras, Steven J.; Jensen, Philip J.; England, Jeffery L.; LeDuc, Dan

    2014-09-24

    This report identifies shipping packages/casks that might be used by the Used Nuclear Fuel Disposition Campaign Program (UFDC) to ship fuel rods and pieces of fuel rods taken from high-burnup used nuclear fuel (UNF) assemblies to and between research facilities for purposes of evaluation and testing. Also identified are the actions that would need to be taken, if any, to obtain U.S. Nuclear Regulatory (NRC) or other regulatory authority approval to use each of the packages and/or shipping casks for this purpose.

  13. 46 CFR 154.449 - Model test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Model test. 154.449 Section 154.449 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type B § 154.449 Model test. The...

  14. 46 CFR 154.431 - Model test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Model test. 154.431 Section 154.431 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Membrane Tanks § 154.431 Model test. (a) The primary...

  15. Performance testing of the Silo Flow Model

    SciTech Connect

    Stadler, S.P.; O`Connor, D.; Gould, A.F.

    1994-12-31

    Several instruments are commercially available for on-line analysis of coal properties such as total moisture, ash, sulfur, and mineral matter content. These instruments have found use in coal cleaning and coal-fired utility applications. However, in many instances, the coal is stored in large bunkers or silos after on-line analysis, making the data gathered from on-line analysis a poor predictor of short-term coal quality due to the flow pattern and mixing within the silo. A computerized model, the Silo Flow Model, has been developed to model the flow of coal through a silo or bunker thus providing a prediction of the output coal quality based on on-line measurements of the quality of coal entering the silo. A test procedure was developed and demonstrated to test the performance of the Silo Flow Model. The testing was performed using controlled addition of silver nitrate to the coal, in conjunction with surface profile measurements using an array of ultrasonic gauges and data acquired from plant instrumentation. Results obtained from initial testing provided estimates of flow-related parameters used in the Silo flow Model. Similar test techniques are also used to compare predicted and actual silver content at the silo outlet as a measure of model performance. This paper describes test procedures used to validate the Silo Flow Model, the testing program, and the results obtained to data. The Silo Flow Model performance is discussed and compared against other modeling approaches.

  16. XMM tests galaxy evolutions models

    NASA Astrophysics Data System (ADS)

    Miniati, Francesco

    2011-10-01

    Current models of galaxy evolution rely critically on feedback supernova and AGN feedback processes. The energy released by past star formation and AGN activity imprints a fossil record on the thermodynamic properties of the intra-group-medium (IGM). This can be decoded by studying the X-ray emission. for an unbiased sample of groups with known galaxy and AGN properties. Therefore we propose an X-ray survey with XMM-Newton for 255 ksec to observe 17 galaxy groups with Msim10(13) M_odot selected from our Zurich ENvironmental Survey that host >8 members.

  17. Building Test Cases through Model Driven Engineering

    NASA Astrophysics Data System (ADS)

    Sousa, Helaine; Lopes, Denivaldo; Abdelouahab, Zair; Hammoudi, Slimane; Claro, Daniela Barreiro

    Recently, Model Driven Engineering (MDE) has been proposed to face the complexity in the development, maintenance and evolution of large and distributed software systems. Model Driven Architecture (MDA) is an example of MDE. In this context, model transformations enable a large reuse of software systems through the transformation of a Platform Independent Model into a Platform Specific Model. Although source code can be generated from models, defects can be injected during the modeling or transformation process. In order to delivery software systems without defects that cause errors and fails, the source code must be submitted to test. In this paper, we present an approach that takes care of test in the whole software life cycle, i.e. it starts in the modeling level and finishes in the test of source code of software systems. We provide an example to illustrate our approach.

  18. Virtual model test for a Francis turbine

    NASA Astrophysics Data System (ADS)

    Kurosawa, S.; Lim, S. M.; Enomoto, Y.

    2010-08-01

    High accuracy performance prediction method based on entire flow passage for a Francis turbine is presented. The performance is predicted by solving unsteady Reynolds-Averaged Navier-Stokes equations combined with Reynolds- Stress model and Bubble two-phase flow model. The prediction accuracy was evaluated to compare with the model test results for three different specific speed turbines. By comparing the simulation results with model test results for efficiency characteristic, pressure fluctuation characteristic and cavitation characteristic, it was proved that numerical model test presented in this paper could predict important characteristics of Francis turbine with high accuracy not only quantitatively but also qualitatively. As a result, it was concluded that numerical model test is going to be a more realistic estimation tool for hydraulic performance of Francis turbine and hence contributes to cost reduction in the development of Francis turbine.

  19. Collider Tests of the Little Higgs Model

    SciTech Connect

    Burdman, Gustavo; Perelstein, Maxim; Pierce, Aaron

    2002-12-16

    The little Higgs model provides an alternative to traditional candidates for new physics at the TeV scale. The new heavy gauge bosons predicted by this model should be observable at the Large Hadron Collider (LHC). We discuss how the LHC experiments could test the little Higgs model by studying the production and decay of these particles.

  20. The Vanishing Tetrad Test: Another Test of Model Misspecification

    ERIC Educational Resources Information Center

    Roos, J. Micah

    2014-01-01

    The Vanishing Tetrad Test (VTT) (Bollen, Lennox, & Dahly, 2009; Bollen & Ting, 2000; Hipp, Bauer, & Bollen, 2005) is an extension of the Confirmatory Tetrad Analysis (CTA) proposed by Bollen and Ting (Bollen & Ting, 1993). VTT is a powerful tool for detecting model misspecification and can be particularly useful in cases in which…

  1. Do Test Design and Uses Influence Test Preparation? Testing a Model of Washback with Structural Equation Modeling

    ERIC Educational Resources Information Center

    Xie, Qin; Andrews, Stephen

    2013-01-01

    This study introduces Expectancy-value motivation theory to explain the paths of influences from perceptions of test design and uses to test preparation as a special case of washback on learning. Based on this theory, two conceptual models were proposed and tested via Structural Equation Modeling. Data collection involved over 870 test takers of…

  2. Superconducting solenoid model magnet test results

    SciTech Connect

    Carcagno, R.; Dimarco, J.; Feher, S.; Ginsburg, C.M.; Hess, C.; Kashikhin, V.V.; Orris, D.F.; Pischalnikov, Y.; Sylvester, C.; Tartaglia, M.A.; Terechkine, I.; /Fermilab

    2006-08-01

    Superconducting solenoid magnets suitable for the room temperature front end of the Fermilab High Intensity Neutrino Source (formerly known as Proton Driver), an 8 GeV superconducting H- linac, have been designed and fabricated at Fermilab, and tested in the Fermilab Magnet Test Facility. We report here results of studies on the first model magnets in this program, including the mechanical properties during fabrication and testing in liquid helium at 4.2 K, quench performance, and magnetic field measurements. We also describe new test facility systems and instrumentation that have been developed to accomplish these tests.

  3. Graphical Models and Computerized Adaptive Testing.

    ERIC Educational Resources Information Center

    Almond, Russell G.; Mislevy, Robert J.

    1999-01-01

    Considers computerized adaptive testing from the perspective of graphical modeling (GM). GM provides methods for making inferences about multifaceted skills and knowledge and for extracting data from complex performances. Provides examples from language-proficiency assessment. (SLD)

  4. Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing

    NASA Technical Reports Server (NTRS)

    Nance, Donald; Liever, Peter; Nielsen, Tanner

    2015-01-01

    The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test, conducted at Marshall Space Flight Center. The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.

  5. Space Launch System Scale Model Acoustic Test Ignition Overpressure Testing

    NASA Technical Reports Server (NTRS)

    Nance, Donald K.; Liever, Peter A.

    2015-01-01

    The overpressure phenomenon is a transient fluid dynamic event occurring during rocket propulsion system ignition. This phenomenon results from fluid compression of the accelerating plume gas, subsequent rarefaction, and subsequent propagation from the exhaust trench and duct holes. The high-amplitude unsteady fluid-dynamic perturbations can adversely affect the vehicle and surrounding structure. Commonly known as ignition overpressure (IOP), this is an important design-to environment for the Space Launch System (SLS) that NASA is currently developing. Subscale testing is useful in validating and verifying the IOP environment. This was one of the objectives of the Scale Model Acoustic Test (SMAT), conducted at Marshall Space Flight Center (MSFC). The test data quantifies the effectiveness of the SLS IOP suppression system and improves the analytical models used to predict the SLS IOP environments. The reduction and analysis of the data gathered during the SMAT IOP test series requires identification and characterization of multiple dynamic events and scaling of the event waveforms to provide the most accurate comparisons to determine the effectiveness of the IOP suppression systems. The identification and characterization of the overpressure events, the waveform scaling, the computation of the IOP suppression system knockdown factors, and preliminary comparisons to the analytical models are discussed.

  6. A defect in the RNA-processing protein HNRPDL causes limb-girdle muscular dystrophy 1G (LGMD1G).

    PubMed

    Vieira, Natássia M; Naslavsky, Michel S; Licinio, Luciana; Kok, Fernando; Schlesinger, David; Vainzof, Mariz; Sanchez, Nury; Kitajima, João Paulo; Gal, Lihi; Cavaçana, Natale; Serafini, Peter R; Chuartzman, Silvia; Vasquez, Cristina; Mimbacas, Adriana; Nigro, Vincenzo; Pavanello, Rita C; Schuldiner, Maya; Kunkel, Louis M; Zatz, Mayana

    2014-08-01

    Limb-girdle muscular dystrophies (LGMD) are a heterogeneous group of genetically determined muscle disorders with a primary or predominant involvement of the pelvic or shoulder girdle musculature. More than 20 genes with autosomal recessive (LGMD2A to LGMD2Q) and autosomal dominant inheritance (LGMD1A to LGMD1H) have been mapped/identified to date. Mutations are known for six among the eight mapped autosomal dominant forms: LGMD1A (myotilin), LGMD1B (lamin A/C), LGMD1C (caveolin-3), LGMD1D (desmin), LGMD1E (DNAJB6), and more recently for LGMD1F (transportin-3). Our group previously mapped the LGMD1G gene at 4q21 in a Caucasian-Brazilian family. We now mapped a Uruguayan family with patients displaying a similar LGMD1G phenotype at the same locus. Whole genome sequencing identified, in both families, mutations in the HNRPDL gene. HNRPDL is a heterogeneous ribonucleoprotein family member, which participates in mRNA biogenesis and metabolism. Functional studies performed in S. cerevisiae showed that the loss of HRP1 (yeast orthologue) had pronounced effects on both protein levels and cell localizations, and yeast proteome revealed dramatic reorganization of proteins involved in RNA-processing pathways. In vivo analysis showed that hnrpdl is important for muscle development in zebrafish, causing a myopathic phenotype when knocked down. The present study presents a novel association between a muscular disorder and a RNA-related gene and reinforces the importance of RNA binding/processing proteins in muscle development and muscle disease. Understanding the role of these proteins in muscle might open new therapeutic approaches for muscular dystrophies. PMID:24647604

  7. Sample Size Determination for Rasch Model Tests

    ERIC Educational Resources Information Center

    Draxler, Clemens

    2010-01-01

    This paper is concerned with supplementing statistical tests for the Rasch model so that additionally to the probability of the error of the first kind (Type I probability) the probability of the error of the second kind (Type II probability) can be controlled at a predetermined level by basing the test on the appropriate number of observations.…

  8. Standardized Tests and Froebel's Original Kindergarten Model

    ERIC Educational Resources Information Center

    Jeynes, William H.

    2006-01-01

    The author argues that American educators rely on standardized tests at too early an age when administered in kindergarten, particularly given the original intent of kindergarten as envisioned by its founder, Friedrich Froebel. The author examines the current use of standardized tests in kindergarten and the Froebel model, including his emphasis…

  9. Component Latent Trait Models for Test Design.

    ERIC Educational Resources Information Center

    Embretson, Susan Whitely

    Latent trait models are presented that can be used for test design in the context of a theory about the variables that underlie task performance. Examples of methods for decomposing and testing hypotheses about the theoretical variables in task performance are given. The methods can be used to determine the processing components that are involved…

  10. Transformation model selection by multiple hypotheses testing

    NASA Astrophysics Data System (ADS)

    Lehmann, Rüdiger

    2014-12-01

    Transformations between different geodetic reference frames are often performed such that first the transformation parameters are determined from control points. If in the first place we do not know which of the numerous transformation models is appropriate then we can set up a multiple hypotheses test. The paper extends the common method of testing transformation parameters for significance, to the case that also constraints for such parameters are tested. This provides more flexibility when setting up such a test. One can formulate a general model with a maximum number of transformation parameters and specialize it by adding constraints to those parameters, which need to be tested. The proper test statistic in a multiple test is shown to be either the extreme normalized or the extreme studentized Lagrange multiplier. They are shown to perform superior to the more intuitive test statistics derived from misclosures. It is shown how model selection by multiple hypotheses testing relates to the use of information criteria like AICc and Mallows' , which are based on an information theoretic approach. Nevertheless, whenever comparable, the results of an exemplary computation almost coincide.

  11. Modeling Nonignorable Missing Data in Speeded Tests

    ERIC Educational Resources Information Center

    Glas, Cees A. W.; Pimentel, Jonald L.

    2008-01-01

    In tests with time limits, items at the end are often not reached. Usually, the pattern of missing responses depends on the ability level of the respondents; therefore, missing data are not ignorable in statistical inference. This study models data using a combination of two item response theory (IRT) models: one for the observed response data and…

  12. Modeling Answer Changes on Test Items

    ERIC Educational Resources Information Center

    van der Linden, Wim J.; Jeon, Minjeong

    2012-01-01

    The probability of test takers changing answers upon review of their initial choices is modeled. The primary purpose of the model is to check erasures on answer sheets recorded by an optical scanner for numbers and patterns that may be indicative of irregular behavior, such as teachers or school administrators changing answer sheets after their…

  13. Numerical modeling for underground nuclear test monitoring

    NASA Astrophysics Data System (ADS)

    Taylor, Steven R.; Kamm, James R.

    The symposium for Numerical Modeling for Underground Nuclear Test Monitoring was held March 23-25 in Durango, Colo. Funded by the DOE Office of Arms Control and Nonproliferation (OACN) and hosted by the Source Region Program at Los Alamos National Laboratory (LANL), the meetings's purpose was to discuss the state-of-the-art in numerical simulations of nuclear explosion phenomenology with applications to test-ban monitoring. In particular, we wished to focus on the uniqueness of model fits to data, the measurement and characterization of material response models, advanced modeling techniques, and applications of modeling to monitoring problems.The concept for the meeting arose through discussions with Marv Denny, who was on assignment at Department of Energy Headquarters from Lawrence Livermore National Laboratory (LLNL). In these conversations, the following question was discussed: how are numerical modeling techniques being used to understand the effects of explosion- source phenomenology on test-ban treaty monitoring? Numerical studies are becoming increasingly important in the evaluation of capabilities for proliferation monitoring; this trend has accelerated with the curtailment of the nuclear testing program. During these discussions, the issue of the uniqueness and limitations of numerical models arose. It was decided to address these questions by convening a group of experts to present and discuss the problems associated with modeling of close-in data from explosions.

  14. Discrete Element Modeling of Drop Tests

    NASA Astrophysics Data System (ADS)

    Wang, Yuannian; Tonon, Fulvio

    2012-09-01

    A discrete element code with impact model has been developed and calibrated to simulate the dynamic behavior of rock materials, with special regard to rock fragmentation upon impact during rock-fall analysis. The paper summarizes the discrete element code, the calibration algorithms developed to identify the model microparameters, and the impact model. Experimental work on drop tests is then used to validate the code on modeling impact fragmentation. It has been found that the developed discrete element code and impact model can reasonably simulate rock fragmentation in drop tests. The use of the discrete element code and impact model can provide good reference results in evaluating impact fragmentation in rock-fall analysis.

  15. SOFIA telescope modal survey test and test-model correlation

    NASA Astrophysics Data System (ADS)

    Keas, Paul; Brewster, Rick; Guerra, Jorge; Lampater, Ulrich; Kärcher, Hans; Teufel, Stefan; Wagner, Jörg

    2010-07-01

    The NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA) employs a 2.5-meter reflector telescope in a Boeing 747SP. The telescope is housed in an open cavity and will be subjected to aeroacoustic and inertial disturbances. The image stability goal for SOFIA is 0.2 arc-seconds (RMS). Throughout the development phase of the project, analytical models were employed to predict the image stability performance of the telescope, and to evaluate pointing performance improvement measures. These analyses clearly demonstrated that key aspects which determined performance were: 1) Disturbance environment and relevant load-paths 2) Telescope modal behavior 3) Sensor and actuator placement 4) Control algorithm design The SOFIA program is now entering an exciting phase in which the characteristics of the telescope and the cavity environment are being verified through ground and airborne testing. A modal survey test (MST) was conducted in early 2008 to quantify the telescope modal behavior. We will give a brief overview of analytical methods which have been employed to assess/improve the pointing stability performance of the SOFIA telescope. In this context, we will describe the motivation for the MST, and the pre-test analysis which determined the modes of interest and the required MST sensor/shaker placement. A summary will then be given of the FEM-test correlation effort, updated end-to-end simulation results, and actual data coming from telescope activation test flights.

  16. Water Model Tests for Semirigid Airships

    NASA Technical Reports Server (NTRS)

    Tuckerman, L.B.

    1926-01-01

    The design of complicated structures often presents problems of extreme difficulty which are frequently insoluble. In many cases, however, the solution can be obtained by tests on suitable models. These model tests are becoming so important a part of the design of new engineering structures that their theory has become a necessary part of an engineer's knowledge. For balloons and airships water models are used. These are models about 1/30 the size of the airship hung upside down and filled with water under pressure. The theory shows that the stresses in such a model are the same as in the actual airship. In the design of the Army Semirigid Airship RS-1 no satisfactory way was found to calculate the stresses in the keel due to the changing shape of the bag. For this purpose a water model with a flexible keel was built and tested. This report gives the theory of the design, construction, and testing of such a water model.

  17. A 'Turing' Test for Landscape Evolution Models

    NASA Astrophysics Data System (ADS)

    Parsons, A. J.; Wise, S. M.; Wainwright, J.; Swift, D. A.

    2008-12-01

    Resolving the interactions among tectonics, climate and surface processes at long timescales has benefited from the development of computer models of landscape evolution. However, testing these Landscape Evolution Models (LEMs) has been piecemeal and partial. We argue that a more systematic approach is required. What is needed is a test that will establish how 'realistic' an LEM is and thus the extent to which its predictions may be trusted. We propose a test based upon the Turing Test of artificial intelligence as a way forward. In 1950 Alan Turing posed the question of whether a machine could think. Rather than attempt to address the question directly he proposed a test in which an interrogator asked questions of a person and a machine, with no means of telling which was which. If the machine's answer could not be distinguished from those of the human, the machine could be said to demonstrate artificial intelligence. By analogy, if an LEM cannot be distinguished from a real landscape it can be deemed to be realistic. The Turing test of intelligence is a test of the way in which a computer behaves. The analogy in the case of an LEM is that it should show realistic behaviour in terms of form and process, both at a given moment in time (punctual) and in the way both form and process evolve over time (dynamic). For some of these behaviours, tests already exist. For example there are numerous morphometric tests of punctual form and measurements of punctual process. The test discussed in this paper provides new ways of assessing dynamic behaviour of an LEM over realistically long timescales. However challenges remain in developing an appropriate suite of challenging tests, in applying these tests to current LEMs and in developing LEMs that pass them.

  18. Structural Integrity Recording System (SIR) for U.S. Army AH-1G Helicopters

    NASA Astrophysics Data System (ADS)

    Farrell, T. G.; Johnson, R. B.; Tyler, M. C.

    1981-03-01

    A Structural Integrity Recording System (SIRS) was designed and developed to track the fatigue damage accumulation on 10 critical helicopter components for the subsequent timely replacement of such components for safer and more economical helicopter operation. SIRS comprises three discrete but interrelated subsystems: an airborne microprocessor-based recorder, a portable flight-line data retrieval unit, and a software system. The validation of SIRS, initially configured for the AH-1G helicopter, consisted of two phases. Phase I (Development Test and Evaluation - DT E) covered the design, fabrication, laboratory qualification testing, reliability analysis, and flight-testing of the prototype SIRS recorder. Phase II (Initial Operational Test and Evaluation - IOT E) covered the evaluation of the entire system operation and the resultant data acquired during a 3-month recording period with five AH-1G's, each equipped with a SIRS recorder. As the documentation of both DT E and IOT E, this report describes the characteristics and functions of the entire system and details the successful performance of the SIRS recorder in the laboratory qualification testing and the flight environment. The SIRS recorder performed as designed, operated reliably, and yielded valid data.

  19. Tay-Sachs disease in Brazilian patients: prevalence of the IVS7+1g>c mutation.

    PubMed

    Rozenberg, R; Martins, A M; Micheletti, C; Mustacchi, Z; Pereira, L V

    2004-01-01

    Seven Brazilian Tay-Sachs disease cases were screened for the most frequent causative mutations. They all presented at least one copy of the IVS7+1g>c mutation. Three patients were homozygotes, three were compound heterozygotes, and in one case only the mother was tested and shown to carry the IVS7+1g>c mutation. In the second allele the compound heterozygotes presented: R178H (the DN allele), InsTATC1278 and an unidentified mutation. The IVS7+1g>c mutation has already been described in three Portuguese patients. In this study, all families were unaware of any Portuguese ancestry. Since Brazil was a Portuguese colony, the mutation most probably came from ancient common ancestry. The initial molecular analysis of Tay-Sachs disease patients in Brazil indicated a prevalence of the IVS7+1g>c mutation, possibly as a result of genetic drift. PMID:15065574

  20. Kinematic tests of exotic flat cosmological models

    SciTech Connect

    Charlton, J.C.; Turner, M.S.

    1986-05-01

    Theoretical prejudice and inflationary models of the very early Universe strongly favor the flat, Einstein-deSitter model of the Universe. At present the observational data conflict with this prejudice. This conflict can be resolved by considering flat models of the Universe which possess a smooth component by energy density. We study in detail the kinematics of such models, where the smooth component is relativistic particles, a cosmological term, a network of light strings, or fast-moving, light strings. We also discuss the observational tests which can be used to discriminate between these models. These tests include the magnitude-redshift, lookback time-redshift, angular size-redshift, and comoving volume-redshift diagrams and the growth of density fluctuations.

  1. A New Way of Testing Large Thin Membrane, Optical Modal Testing of the 1/10th Scale Model of the NASA NAGT Sunshield

    NASA Technical Reports Server (NTRS)

    Ross, Brian

    1999-01-01

    The Next Generation Space Telescope design includes a deployed sunshield to thermally insulate the telescope, keeping vital detector temperatures below 60 degrees Kelvin. The sunshield consists of four struts supporting four thin film membranes. Since it would be very difficult to test the full-scale sunshield on the ground due to its size and the 1-g environment, it is important to have accurate analytical models of the sunshield to analyze its affect on the observatory. A 1/10th-scale model of the sunshield has been manufactured in order to test the analytical modeling techniques used to predict the dynamic behavior of such large, lightweight structures. A modal survey test of the scale model has been performed in a vacuum environment, using a laser vibrometer to measure the mode shapes of the membranes. The presentation describes the setup and test procedures related to these tests and presents some of the experimental results obtained and the lessons learned.

  2. Molecular Sieve Bench Testing and Computer Modeling

    NASA Technical Reports Server (NTRS)

    Mohamadinejad, Habib; DaLee, Robert C.; Blackmon, James B.

    1995-01-01

    The design of an efficient four-bed molecular sieve (4BMS) CO2 removal system for the International Space Station depends on many mission parameters, such as duration, crew size, cost of power, volume, fluid interface properties, etc. A need for space vehicle CO2 removal system models capable of accurately performing extrapolated hardware predictions is inevitable due to the change of the parameters which influences the CO2 removal system capacity. The purpose is to investigate the mathematical techniques required for a model capable of accurate extrapolated performance predictions and to obtain test data required to estimate mass transfer coefficients and verify the computer model. Models have been developed to demonstrate that the finite difference technique can be successfully applied to sorbents and conditions used in spacecraft CO2 removal systems. The nonisothermal, axially dispersed, plug flow model with linear driving force for 5X sorbent and pore diffusion for silica gel are then applied to test data. A more complex model, a non-darcian model (two dimensional), has also been developed for simulation of the test data. This model takes into account the channeling effect on column breakthrough. Four FORTRAN computer programs are presented: a two-dimensional model of flow adsorption/desorption in a packed bed; a one-dimensional model of flow adsorption/desorption in a packed bed; a model of thermal vacuum desorption; and a model of a tri-sectional packed bed with two different sorbent materials. The programs are capable of simulating up to four gas constituents for each process, which can be increased with a few minor changes.

  3. Pile Model Tests Using Strain Gauge Technology

    NASA Astrophysics Data System (ADS)

    Krasiński, Adam; Kusio, Tomasz

    2015-09-01

    Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model. To find a suitable solution for axial force measurement, which could be applied to small scale model piles, we had to take into account the following requirements: - a linear and stable relationship between measured and physical values, - the force measurement accuracy of about 0.1 kN, - the range of measured forces up to 30 kN, - resistance of measuring gauges against aggressive counteraction of concrete mortar and against moisture, - insensitivity to pile bending, - economical factor. These requirements can be fulfilled by strain gauge sensors if an appropriate methodology is used for test preparation (Hoffmann [1]). In this paper, we focus on some aspects of the application of strain gauge sensors for model pile tests. The efficiency of the method is proved on the examples of static load tests carried out on SDP model piles acting as single piles and in a group.

  4. Impact of uncertainty on modeling and testing

    NASA Technical Reports Server (NTRS)

    Coleman, Hugh W.; Brown, Kendall K.

    1995-01-01

    A thorough understanding of the uncertainties associated with the modeling and testing of the Space Shuttle Main Engine (SSME) Engine will greatly aid decisions concerning hardware performance and future development efforts. This report will describe the determination of the uncertainties in the modeling and testing of the Space Shuttle Main Engine test program at the Technology Test Bed facility at Marshall Space Flight Center. Section 2 will present a summary of the uncertainty analysis methodology used and discuss the specific applications to the TTB SSME test program. Section 3 will discuss the application of the uncertainty analysis to the test program and the results obtained. Section 4 presents the results of the analysis of the SSME modeling effort from an uncertainty analysis point of view. The appendices at the end of the report contain a significant amount of information relative to the analysis, including discussions of venturi flowmeter data reduction and uncertainty propagation, bias uncertainty documentations, technical papers published, the computer code generated to determine the venturi uncertainties, and the venturi data and results used in the analysis.

  5. Unit testing, model validation, and biological simulation

    PubMed Central

    Watts, Mark D.; Ghayoomie, S. Vahid; Larson, Stephen D.; Gerkin, Richard C.

    2016-01-01

    The growth of the software industry has gone hand in hand with the development of tools and cultural practices for ensuring the reliability of complex pieces of software. These tools and practices are now acknowledged to be essential to the management of modern software. As computational models and methods have become increasingly common in the biological sciences, it is important to examine how these practices can accelerate biological software development and improve research quality. In this article, we give a focused case study of our experience with the practices of unit testing and test-driven development in OpenWorm, an open-science project aimed at modeling Caenorhabditis elegans. We identify and discuss the challenges of incorporating test-driven development into a heterogeneous, data-driven project, as well as the role of model validation tests, a category of tests unique to software which expresses scientific models.

  6. Flight Test Maneuvers for Efficient Aerodynamic Modeling

    NASA Technical Reports Server (NTRS)

    Morelli, Eugene A.

    2011-01-01

    Novel flight test maneuvers for efficient aerodynamic modeling were developed and demonstrated in flight. Orthogonal optimized multi-sine inputs were applied to aircraft control surfaces to excite aircraft dynamic response in all six degrees of freedom simultaneously while keeping the aircraft close to chosen reference flight conditions. Each maneuver was designed for a specific modeling task that cannot be adequately or efficiently accomplished using conventional flight test maneuvers. All of the new maneuvers were first described and explained, then demonstrated on a subscale jet transport aircraft in flight. Real-time and post-flight modeling results obtained using equation-error parameter estimation in the frequency domain were used to show the effectiveness and efficiency of the new maneuvers, as well as the quality of the aerodynamic models that can be identified from the resultant flight data.

  7. Th17 Cell Response in SOD1(G93A) Mice following Motor Nerve Injury.

    PubMed

    Ni, Allen; Yang, Tao; Mesnard-Hoaglin, Nichole A; Gutierrez, Rafael; Stubbs, Evan B; McGuire, Susan O; Sanders, Virginia M; Jones, Kathryn J; Foecking, Eileen M; Xin, Junping

    2016-01-01

    An increased risk of ALS has been reported for veterans, varsity athletes, and professional football players. The mechanism underlying the increased risk in these populations has not been identified; however, it has been proposed that motor nerve injury may trigger immune responses which, in turn, can accelerate the progression of ALS. Accumulating evidence indicates that abnormal immune reactions and inflammation are involved in the pathogenesis of ALS, but the specific immune cells involved have not been clearly defined. To understand how nerve injury and immune responses may contribute to ALS development, we investigated responses of CD4(+) T cell after facial motor nerve axotomy (FNA) at a presymptomatic stage in a transgenic mouse model of ALS (B6SJL SOD1(G93A)). SOD1(G93A) mice, compared with WT mice, displayed an increase in the basal activation state of CD4(+) T cells and higher frequency of Th17 cells, which were further enhanced by FNA. In conclusion, SOD1(G93A) mice exhibit abnormal CD4(+) T cell activation with increased levels of Th17 cells prior to the onset of neurological symptoms. Motor nerve injury exacerbates Th17 cell responses and may contribute to the development of ALS, especially in those who carry genetic susceptibility to this disease. PMID:27194826

  8. Th17 Cell Response in SOD1G93A Mice following Motor Nerve Injury

    PubMed Central

    Ni, Allen; Yang, Tao; Mesnard-Hoaglin, Nichole A.; Gutierrez, Rafael; Stubbs, Evan B.; McGuire, Susan O.; Sanders, Virginia M.; Jones, Kathryn J.; Foecking, Eileen M.; Xin, Junping

    2016-01-01

    An increased risk of ALS has been reported for veterans, varsity athletes, and professional football players. The mechanism underlying the increased risk in these populations has not been identified; however, it has been proposed that motor nerve injury may trigger immune responses which, in turn, can accelerate the progression of ALS. Accumulating evidence indicates that abnormal immune reactions and inflammation are involved in the pathogenesis of ALS, but the specific immune cells involved have not been clearly defined. To understand how nerve injury and immune responses may contribute to ALS development, we investigated responses of CD4+ T cell after facial motor nerve axotomy (FNA) at a presymptomatic stage in a transgenic mouse model of ALS (B6SJL SOD1G93A). SOD1G93A mice, compared with WT mice, displayed an increase in the basal activation state of CD4+ T cells and higher frequency of Th17 cells, which were further enhanced by FNA. In conclusion, SOD1G93A mice exhibit abnormal CD4+ T cell activation with increased levels of Th17 cells prior to the onset of neurological symptoms. Motor nerve injury exacerbates Th17 cell responses and may contribute to the development of ALS, especially in those who carry genetic susceptibility to this disease. PMID:27194826

  9. H, G1, G2 photometric phase function extended to low-accuracy data

    NASA Astrophysics Data System (ADS)

    Penttilä, A.; Shevchenko, V. G.; Wilkman, O.; Muinonen, K.

    2016-04-01

    We introduce a constrained nonlinear least-squares algorithm to be used in estimating the parameters in the H, G1, G2 phase function. As the algorithm works directly in the magnitude space, it will surpass the possible bias problem that may be present in the existing H ,G1 ,G2 fit procedure when applied to low-accuracy observations with large magnitude variations. With constraints on the photometric phase-curve shape parameters G1 and G2, it guarantees a physically reasonable phase-curve estimate. With a new data set of 93 asteroids, we re-assess the two-parameter version of the H ,G1 ,G2 function. Finally, we introduce a one-parameter version of the phase function that can give a suggestion of the asteroids taxonomic group based only on its phase curve. A statistical model selection procedure is presented that can automatically select between the different versions of the photometric phase functions. An online tool that implements these algorithms is introduced.

  10. Tritium transfer in pigs - A model test

    SciTech Connect

    Melintescu, A.; Galeriu, D.

    2008-07-15

    In the frame of IAEA EMRAS (Environmental Modelling for Radiation Safety) programme, there was developed a scenario for models ' testing starting with unpublished data for a sow fed with OBT for 84 days. The scenario includes model predictions for the dynamics of tritium in urine and faeces and HTO and OBT in organs at sacrifice. There have been done two inter-comparison exercises and most of the models succeeded to give predictions better than a factor 3 to 5, excepting faeces. There has been done an analysis of models' structure, performance and limits in order to be able to build a model of moderate complexity with a reliable predictive power, able to be applied for human dosimetry, also, when OBT data are missing. (authors)

  11. CPAS Parachute Testing, Model Development, & Verification

    NASA Technical Reports Server (NTRS)

    Romero, Leah M.

    2013-01-01

    Capsule Parachute Assembly System (CPAS) is the human rated parachute system for the Orion vehicle used during re-entry. Similar to Apollo parachute design. Human rating requires additional system redundancy. A Government Furnished Equipment (GFE) project responsible for: Design; Development testing; Performance modeling; Fabrication; Qualification; Delivery

  12. Advanced air revitalization system modeling and testing

    NASA Technical Reports Server (NTRS)

    Dall-Baumann, Liese; Jeng, Frank; Christian, Steve; Edeer, Marybeth; Lin, Chin

    1990-01-01

    To support manned lunar and Martian exploration, an extensive evaluation of air revitalization subsystems (ARS) is being conducted. The major operations under study include carbon dioxide removal and reduction; oxygen and nitrogen production, storage, and distribution; humidity and temperature control; and trace contaminant control. A comprehensive analysis program based on a generalized block flow model was developed to facilitate the evaluation of various processes and their interaction. ASPEN PLUS was used in modelling carbon dioxide removal and reduction. Several life support test stands were developed to test new and existing technologies for their potential applicability in space. The goal was to identify processes which use compact, lightweight equipment and maximize the recovery of oxygen and water. The carbon dioxide removal test stands include solid amine/vacuum desorption (SAVD), regenerative silver oxide chemisorption, and electrochemical carbon dioxide concentration (EDC). Membrane-based carbon dioxide removal and humidity control, catalytic reduction of carbon dioxide, and catalytic oxidation of trace contaminants were also investigated.

  13. Mechanism test bed. Flexible body model report

    NASA Technical Reports Server (NTRS)

    Compton, Jimmy

    1991-01-01

    The Space Station Mechanism Test Bed is a six degree-of-freedom motion simulation facility used to evaluate docking and berthing hardware mechanisms. A generalized rigid body math model was developed which allowed the computation of vehicle relative motion in six DOF due to forces and moments from mechanism contact, attitude control systems, and gravity. No vehicle size limitations were imposed in the model. The equations of motion were based on Hill's equations for translational motion with respect to a nominal circular earth orbit and Newton-Euler equations for rotational motion. This rigid body model and supporting software were being refined.

  14. Viking 1975 Orbiter Development Test Model/Lander Dynamic Test Model dynamic environmental testing - An overview

    NASA Technical Reports Server (NTRS)

    Milder, G.

    1975-01-01

    The current work presents an overview of the Viking 1975 environmental testing from an engineering standpoint. An extremely large vibration test fixture had to be designed, analyzed, and integrated into a test setup that employed hydrostatic bearings in a new fashion. A vibration control system was also required that would allow for thirty-six channels of sine-wave peak select control from acceleration, force-of-strain transducers. In addition, some 68 channels of peak limiting shutdown capability were needed for backup and monitoring of other data during the forced vibration test. Pretesting included analyses of the fixture design, overturning moment, control system capabilities, and response of the entire spacecraft/fixture/exciter system to the test environment. Closed-loop control for acoustic testing was a necessity due to the fact that the Viking spacecraft took up a major portion of the volume of the 10,000 cu ft chamber. The spacecraft emerged from testing undamaged.

  15. Testing mechanistic models of growth in insects.

    PubMed

    Maino, James L; Kearney, Michael R

    2015-11-22

    Insects are typified by their small size, large numbers, impressive reproductive output and rapid growth. However, insect growth is not simply rapid; rather, insects follow a qualitatively distinct trajectory to many other animals. Here we present a mechanistic growth model for insects and show that increasing specific assimilation during the growth phase can explain the near-exponential growth trajectory of insects. The presented model is tested against growth data on 50 insects, and compared against other mechanistic growth models. Unlike the other mechanistic models, our growth model predicts energy reserves per biomass to increase with age, which implies a higher production efficiency and energy density of biomass in later instars. These predictions are tested against data compiled from the literature whereby it is confirmed that insects increase their production efficiency (by 24 percentage points) and energy density (by 4 J mg(-1)) between hatching and the attainment of full size. The model suggests that insects achieve greater production efficiencies and enhanced growth rates by increasing specific assimilation and increasing energy reserves per biomass, which are less costly to maintain than structural biomass. Our findings illustrate how the explanatory and predictive power of mechanistic growth models comes from their grounding in underlying biological processes. PMID:26609084

  16. Application of a nonlinear slug test model

    USGS Publications Warehouse

    McElwee, C.D.

    2001-01-01

    Knowledge of the hydraulic conductivity distribution is of utmost importance in understanding the dynamics of an aquifer and in planning the consequences of any action taken upon that aquifer. Slug tests have been used extensively to measure hydraulic conductivity in the last 50 years since Hvorslev's (1951) work. A general nonlinear model based on the Navier-Stokes equation, nonlinear frictional loss, non-Darcian flow, acceleration effects, radius changes in the wellbore, and a Hvorslev model for the aquifer has been implemented in this work. The nonlinear model has three parameters: ??, which is related primarily to radius changes in the water column; A, which is related to the nonlinear head losses; and K, the hydraulic conductivity. An additional parameter has been added representing the initial velocity of the water column at slug initiation and is incorporated into an analytical solution to generate the first time step before a sequential numerical solution generates the remainder of the time solution. Corrections are made to the model output for acceleration before it is compared to the experimental data. Sensitivity analysis and least squares fitting are used to estimate the aquifer parameters and produce some diagnostic results, which indicate the accuracy of the fit. Finally, an example of field data has been presented to illustrate the application of the model to data sets that exhibit nonlinear behavior. Multiple slug tests should be taken at a given location to test for nonlinear effects and to determine repeatability.

  17. Turbulence Modeling Validation, Testing, and Development

    NASA Technical Reports Server (NTRS)

    Bardina, J. E.; Huang, P. G.; Coakley, T. J.

    1997-01-01

    The primary objective of this work is to provide accurate numerical solutions for selected flow fields and to compare and evaluate the performance of selected turbulence models with experimental results. Four popular turbulence models have been tested and validated against experimental data often turbulent flows. The models are: (1) the two-equation k-epsilon model of Wilcox, (2) the two-equation k-epsilon model of Launder and Sharma, (3) the two-equation k-omega/k-epsilon SST model of Menter, and (4) the one-equation model of Spalart and Allmaras. The flows investigated are five free shear flows consisting of a mixing layer, a round jet, a plane jet, a plane wake, and a compressible mixing layer; and five boundary layer flows consisting of an incompressible flat plate, a Mach 5 adiabatic flat plate, a separated boundary layer, an axisymmetric shock-wave/boundary layer interaction, and an RAE 2822 transonic airfoil. The experimental data for these flows are well established and have been extensively used in model developments. The results are shown in the following four sections: Part A describes the equations of motion and boundary conditions; Part B describes the model equations, constants, parameters, boundary conditions, and numerical implementation; and Parts C and D describe the experimental data and the performance of the models in the free-shear flows and the boundary layer flows, respectively.

  18. Parametric Testing of Launch Vehicle FDDR Models

    NASA Technical Reports Server (NTRS)

    Schumann, Johann; Bajwa, Anupa; Berg, Peter; Thirumalainambi, Rajkumar

    2011-01-01

    For the safe operation of a complex system like a (manned) launch vehicle, real-time information about the state of the system and potential faults is extremely important. The on-board FDDR (Failure Detection, Diagnostics, and Response) system is a software system to detect and identify failures, provide real-time diagnostics, and to initiate fault recovery and mitigation. The ERIS (Evaluation of Rocket Integrated Subsystems) failure simulation is a unified Matlab/Simulink model of the Ares I Launch Vehicle with modular, hierarchical subsystems and components. With this model, the nominal flight performance characteristics can be studied. Additionally, failures can be injected to see their effects on vehicle state and on vehicle behavior. A comprehensive test and analysis of such a complicated model is virtually impossible. In this paper, we will describe, how parametric testing (PT) can be used to support testing and analysis of the ERIS failure simulation. PT uses a combination of Monte Carlo techniques with n-factor combinatorial exploration to generate a small, yet comprehensive set of parameters for the test runs. For the analysis of the high-dimensional simulation data, we are using multivariate clustering to automatically find structure in this high-dimensional data space. Our tools can generate detailed HTML reports that facilitate the analysis.

  19. Prospective Tests on Biological Models of Acupuncture

    PubMed Central

    2009-01-01

    The biological effects of acupuncture include the regulation of a variety of neurohumoral factors and growth control factors. In science, models or hypotheses with confirmed predictions are considered more convincing than models solely based on retrospective explanations. Literature review showed that two biological models of acupuncture have been prospectively tested with independently confirmed predictions: The neurophysiology model on the long-term effects of acupuncture emphasizes the trophic and anti-inflammatory effects of acupuncture. Its prediction on the peripheral effect of endorphin in acupuncture has been confirmed. The growth control model encompasses the neurophysiology model and suggests that a macroscopic growth control system originates from a network of organizers in embryogenesis. The activity of the growth control system is important in the formation, maintenance and regulation of all the physiological systems. Several phenomena of acupuncture such as the distribution of auricular acupuncture points, the long-term effects of acupuncture and the effect of multimodal non-specific stimulation at acupuncture points are consistent with the growth control model. The following predictions of the growth control model have been independently confirmed by research results in both acupuncture and conventional biomedical sciences: (i) Acupuncture has extensive growth control effects. (ii) Singular point and separatrix exist in morphogenesis. (iii) Organizers have high electric conductance, high current density and high density of gap junctions. (iv) A high density of gap junctions is distributed as separatrices or boundaries at body surface after early embryogenesis. (v) Many acupuncture points are located at transition points or boundaries between different body domains or muscles, coinciding with the connective tissue planes. (vi) Some morphogens and organizers continue to function after embryogenesis. Current acupuncture research suggests a convergence

  20. S-IC Test Stand Design Model

    NASA Technical Reports Server (NTRS)

    1962-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. This photo is of the S-IC test stand design model created prior to construction.

  1. S-IC Test Stand Design Model

    NASA Technical Reports Server (NTRS)

    1962-01-01

    At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. This photo is of the S-IC test stand design model.

  2. A Blind Test of Hapke's Photometric Model

    NASA Technical Reports Server (NTRS)

    Helfenstein, P.; Shepard, M. K.

    2003-01-01

    Hapke's bidirectional reflectance equation is a versatile analytical tool for predicting (i.e. forward modeling) the photometric behavior of a particulate surface from the observed optical and structural properties of its constituents. Remote sensing applications of Hapke s model, however, generally seek to predict the optical and structural properties of particulate soil constituents from the observed photometric behavior of a planetary surface (i.e. inverse-modeling). Our confidence in the latter approach can be established only if we ruthlessly test and optimize it. Here, we summarize preliminary results from a blind-test of the Hapke model using laboratory measurements obtained with the Bloomsburg University Goniometer (B.U.G.). The first author selected eleven well-characterized powder samples and measured the spectrophotometric behavior of each. A subset of twenty undisclosed examples of the photometric measurement sets were sent to the second author who fit the data using the Hapke model and attempted to interpret their optical and mechanical properties from photometry alone.

  3. The use of models in structural testing.

    NASA Technical Reports Server (NTRS)

    Horton, W. H.; Singhal, M. K.; Haack, T. A.

    1972-01-01

    The design, construction and instrumentation of plastic model shells used in elastic stability studies is discussed. The work demonstrates that specimens made of such materials are of great value in parametric studies because of their ease of manufacture and the simplicity of modification. Additionally, it is shown that they are most useful in the development of nondestructive test techniques. The paper indicates how deformation measurements made at low load levels can be used to accurately predict critical conditions.

  4. Inverse hydrochemical models of aqueous extracts tests

    SciTech Connect

    Zheng, L.; Samper, J.; Montenegro, L.

    2008-10-10

    Aqueous extract test is a laboratory technique commonly used to measure the amount of soluble salts of a soil sample after adding a known mass of distilled water. Measured aqueous extract data have to be re-interpreted in order to infer porewater chemical composition of the sample because porewater chemistry changes significantly due to dilution and chemical reactions which take place during extraction. Here we present an inverse hydrochemical model to estimate porewater chemical composition from measured water content, aqueous extract, and mineralogical data. The model accounts for acid-base, redox, aqueous complexation, mineral dissolution/precipitation, gas dissolution/ex-solution, cation exchange and surface complexation reactions, of which are assumed to take place at local equilibrium. It has been solved with INVERSE-CORE{sup 2D} and been tested with bentonite samples taken from FEBEX (Full-scale Engineered Barrier EXperiment) in situ test. The inverse model reproduces most of the measured aqueous data except bicarbonate and provides an effective, flexible and comprehensive method to estimate porewater chemical composition of clays. Main uncertainties are related to kinetic calcite dissolution and variations in CO2(g) pressure.

  5. Advanced Fuel Cycle Initiative AFC-1D, AFC-1G and AFC-1H Irradiation Report

    SciTech Connect

    Debra J. Utterbeck; Gray Chang

    2005-09-01

    The U. S. Advanced Fuel Cycle Initiative (AFCI) seeks to develop and demonstrate the technologies needed to transmute the long-lived transuranic actinide isotopes contained in spent nuclear fuel into shorter-lived fission products, thereby dramatically decreasing the volume of material requiring disposition and the long-term radiotoxity and heat load of high-level waste sent to a geologic repository. The AFC-1 irradiation experiments on transmutation fuels are expected to provide irradiation performance data on non-fertile and low-fertile fuel forms specifically, irradiation growth and swelling, helium production, fission gas release, fission product and fuel constituent migration, fuel phase equilibria, and fuel-cladding chemical interaction. Contained in this report are the to-date physics evaluations performed on three of the AFC-1 experiments; AFC-1D, AFC-1G and AFC-1H. The AFC-1D irradiation experiment consists of metallic non-fertile fuel compositions with minor actinides for potential use in accelerator driven systems and AFC-1G and AFC-1H irradiation experiments are part of the fast neutron reactor fuel development effort. These experiments are high burnup analogs to previously irradiated experiments and are to be irradiated to = 20 atom % burnup. Results of the evaluations show that AFC-1D will remain in the ATR for approximately 100 additional effective full power days (EFPDs), and AFC-1G and AFC-1H for approximately 300 additional EFPDs in order to reach the desired programmatic burnup. The specific irradiation schedule for these tests will be determined based on future physics evaluations and all results will be documented in subsequent reports.

  6. Ganymede G1 & G2 Encounters - Interior of Ganymede

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Voyager images are used to create a global view of Ganymede. The cut-out reveals the interior structure of this icy moon. This structure consists of four layers based on measurements of Ganymede's gravity field and theoretical analyses using Ganymede's known mass, size and density. Ganymede's surface is rich in water ice and Voyager and Galileo images show features which are evidence of geological and tectonic disruption of the surface in the past. As with the Earth, these geological features reflect forces and processes deep within Ganymede's interior. Based on geochemical and geophysical models, scientists expected Ganymede's interior to either consist of: a) an undifferentiated mixture of rock and ice or b) a differentiated structure with a large lunar sized 'core' of rock and possibly iron overlain by a deep layer of warm soft ice capped by a thin cold rigid ice crust. Galileo's measurement of Ganymede's gravity field during its first and second encounters with the huge moon have basically confirmed the differentiated model and allowed scientists to estimate the size of these layers more accurately. In addition the data strongly suggest that a dense metallic core exists at the center of the rock core. This metallic core suggests a greater degree of heating at sometime in Ganymede's past than had been proposed before and may be the source of Ganymede's magnetic field discovered by Galileo's space physics experiments.

    Galileo's primary 24 month mission includes eleven orbits around Jupiter and will provide observations of Jupiter, its moons and its magnetosphere. The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C.

    This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov.

  7. Testing the Model of Oscillating Magnetic Traps

    NASA Astrophysics Data System (ADS)

    Szaforz, Ż.; Tomczak, M.

    2015-01-01

    The aim of this paper is to test the model of oscillating magnetic traps (the OMT model), proposed by Jakimiec and Tomczak ( Solar Phys. 261, 233, 2010). This model describes the process of excitation of quasi-periodic pulsations (QPPs) observed during solar flares. In the OMT model energetic electrons are accelerated within a triangular, cusp-like structure situated between the reconnection point and the top of a flare loop as seen in soft X-rays. We analyzed QPPs in hard X-ray light curves for 23 flares as observed by Yohkoh. Three independent methods were used. We also used hard X-ray images to localize magnetic traps and soft X-ray images to diagnose thermal plasmas inside the traps. We found that the majority of the observed pulsation periods correlates with the diameters of oscillating magnetic traps, as was predicted by the OMT model. We also found that the electron number density of plasma inside the magnetic traps in the time of pulsation disappearance is strongly connected with the pulsation period. We conclude that the observations are consistent with the predictions of the OMT model for the analyzed set of flares.

  8. Correlation of AH-1G airframe flight vibration data with a coupled rotor-fuselage analysis

    NASA Technical Reports Server (NTRS)

    Sangha, K.; Shamie, J.

    1990-01-01

    The formulation and features of the Rotor-Airframe Comprehensive Analysis Program (RACAP) is described. The analysis employs a frequency domain, transfer matrix approach for the blade structural model, a time domain wake or momentum theory aerodynamic model, and impedance matching for rotor-fuselage coupling. The analysis is applied to the AH-1G helicopter, and a correlation study is conducted on fuselage vibration predictions. The purpose of the study is to evaluate the state-of-the-art in helicopter fuselage vibration prediction technology. The fuselage vibration predicted using RACAP are fairly good in the vertical direction and somewhat deficient in the lateral/longitudinal directions. Some of these deficiencies are traced to the fuselage finite element model.

  9. Seepage Calibration Model and Seepage Testing Data

    SciTech Connect

    P. Dixon

    2004-02-17

    The purpose of this Model Report is to document the Seepage Calibration Model (SCM). The SCM is developed (1) to establish the conceptual basis for the Seepage Model for Performance Assessment (SMPA), and (2) to derive seepage-relevant, model-related parameters and their distributions for use in the SMPA and seepage abstraction in support of the Total System Performance Assessment for License Application (TSPA-LA). The SCM is intended to be used only within this Model Report for the estimation of seepage-relevant parameters through calibration of the model against seepage-rate data from liquid-release tests performed in several niches along the Exploratory Studies Facility (ESF) Main Drift and in the Cross Drift. The SCM does not predict seepage into waste emplacement drifts under thermal or ambient conditions. Seepage predictions for waste emplacement drifts under ambient conditions will be performed with the SMPA (see upcoming REV 02 of CRWMS M&O 2000 [153314]), which inherits the conceptual basis and model-related parameters from the SCM. Seepage during the thermal period is examined separately in the Thermal Hydrologic (TH) Seepage Model (see BSC 2003 [161530]). The scope of this work is (1) to evaluate seepage rates measured during liquid-release experiments performed in several niches in the Exploratory Studies Facility (ESF) and in the Cross Drift, which was excavated for enhanced characterization of the repository block (ECRB); (2) to evaluate air-permeability data measured in boreholes above the niches and the Cross Drift to obtain the permeability structure for the seepage model; (3) to use inverse modeling to calibrate the SCM and to estimate seepage-relevant, model-related parameters on the drift scale; (4) to estimate the epistemic uncertainty of the derived parameters, based on the goodness-of-fit to the observed data and the sensitivity of calculated seepage with respect to the parameters of interest; (5) to characterize the aleatory uncertainty of

  10. Spike Decomposition Technique: Modeling and Performance Tests

    NASA Astrophysics Data System (ADS)

    Nita, Gelu M.; Fleishman, Gregory D.; Gary, Dale E.

    2008-12-01

    We develop an automated technique for fitting the spectral components of solar microwave spike bursts, which are characterized by narrowband spectral features. The algorithm is especially useful for periods when the spikes occur in densely packed clusters, where the algorithm is capable of decomposing overlapping spike structures into individual spectral components. To test the performance and applicability limits of this data reduction tool, we perform comprehensive modeling of spike clusters characterized by various typical bandwidths, spike densities, and amplitude distributions. We find that, for a wide range of favorable combinations of input parameters, the algorithm is able to recover the characteristic features of the modeled distributions within reasonable confidence intervals. Having model-tested the algorithm against spike overlap, broadband spectral background, noise contamination, and possible malfunction of some spectral channels, we apply the technique to a spike cluster recorded by the Chinese Purple Mountain Observatory (PMO) spectrometer, operating above 4.5 GHz. We study the variation of the spike distribution parameters, such as amplitude, bandwidth, and related derived physical parameters, as a function of time. The method can be further applied to observations from other instruments and to other types of fine structures.

  11. Model-Based Software Testing for Object-Oriented Software

    ERIC Educational Resources Information Center

    Biju, Soly Mathew

    2008-01-01

    Model-based testing is one of the best solutions for testing object-oriented software. It has a better test coverage than other testing styles. Model-based testing takes into consideration behavioural aspects of a class, which are usually unchecked in other testing methods. An increase in the complexity of software has forced the software industry…

  12. Model-independent tests of cosmic gravity.

    PubMed

    Linder, Eric V

    2011-12-28

    Gravitation governs the expansion and fate of the universe, and the growth of large-scale structure within it, but has not been tested in detail on these cosmic scales. The observed acceleration of the expansion may provide signs of gravitational laws beyond general relativity (GR). Since the form of any such extension is not clear, from either theory or data, we adopt a model-independent approach to parametrizing deviations to the Einstein framework. We explore the phase space dynamics of two key post-GR functions and derive a classification scheme, and an absolute criterion on accuracy necessary for distinguishing classes of gravity models. Future surveys will be able to constrain the post-GR functions' amplitudes and forms to the required precision, and hence reveal new aspects of gravitation. PMID:22084288

  13. Spike Decomposition Technique: Modeling and Performance Tests

    NASA Astrophysics Data System (ADS)

    Nita, G. M.; Fleishman, G. D.; Gary, D. E.

    2008-05-01

    We develop an automated technique for fitting the spectral components of solar microwave spike bursts characterized by narrow-band (1-50~MHz) features of 1-10~ms duration, which are thought to be due to Electron-Cyclotron Maser emission. The algorithm is especially useful for periods when the spikes occur in densely packed clusters, where the algorithm is capable of decomposing overlapping spike structures into individual spectral components. To test the performance and applicability limits of this forward fitting algorithm, we perform comprehensive modeling of spike clusters characterized by various typical bandwidths, spike densities, and amplitude distributions. We find that, for a wide range of input parameters, the algorithm is able to recover the characteristic features of the modeled distributions within reasonable confidence intervals. Having model-tested the algorithm comprehensively against spike overlap, broadband spectral background, noise contamination, and possible contamination of cross-channel polarization, we apply the technique to observational data obtained from different instruments in different frequency ranges. Specifically, we studied spike clusters recorded by a Chinese Purple Mountain Observatory (PMO) spectrometer above 4.5 GHz and by Owens Valley Solar Array's FASR Subsystem Testbed instrument above 1 GHz. We study variation of the spike distribution parameters, such as amplitude, bandwidth and related derived physical parameters as a function of frequency and time. We discuss the implications of our results for the choice between competing models of spike generation and underlying physical processes. The method can be further applied to observations from other instruments and to other types of radio spectral fine structures. This work was supported in part by NSF grants AST-0607544 and ATM-0707319 and NASA grant NNG06GJ40G to New Jersey Institute of Technology.

  14. Seepage Calibration Model and Seepage Testing Data

    SciTech Connect

    S. Finsterle

    2004-09-02

    The purpose of this Model Report is to document the Seepage Calibration Model (SCM). The SCM was developed (1) to establish the conceptual basis for the Seepage Model for Performance Assessment (SMPA), and (2) to derive seepage-relevant, model-related parameters and their distributions for use in the SMPA and seepage abstraction in support of the Total System Performance Assessment for License Application (TSPA-LA). This Model Report has been revised in response to a comprehensive, regulatory-focused evaluation performed by the Regulatory Integration Team [''Technical Work Plan for: Regulatory Integration Evaluation of Analysis and Model Reports Supporting the TSPA-LA'' (BSC 2004 [DIRS 169653])]. The SCM is intended to be used only within this Model Report for the estimation of seepage-relevant parameters through calibration of the model against seepage-rate data from liquid-release tests performed in several niches along the Exploratory Studies Facility (ESF) Main Drift and in the Cross-Drift. The SCM does not predict seepage into waste emplacement drifts under thermal or ambient conditions. Seepage predictions for waste emplacement drifts under ambient conditions will be performed with the SMPA [''Seepage Model for PA Including Drift Collapse'' (BSC 2004 [DIRS 167652])], which inherits the conceptual basis and model-related parameters from the SCM. Seepage during the thermal period is examined separately in the Thermal Hydrologic (TH) Seepage Model [see ''Drift-Scale Coupled Processes (DST and TH Seepage) Models'' (BSC 2004 [DIRS 170338])]. The scope of this work is (1) to evaluate seepage rates measured during liquid-release experiments performed in several niches in the Exploratory Studies Facility (ESF) and in the Cross-Drift, which was excavated for enhanced characterization of the repository block (ECRB); (2) to evaluate air-permeability data measured in boreholes above the niches and the Cross-Drift to obtain the permeability structure for the seepage model

  15. Testing Physical Models of Passive Membrane Permeation

    PubMed Central

    Leung, Siegfried S. F.; Mijalkovic, Jona; Borrelli, Kenneth; Jacobson, Matthew P.

    2012-01-01

    The biophysical basis of passive membrane permeability is well understood, but most methods for predicting membrane permeability in the context of drug design are based on statistical relationships that indirectly capture the key physical aspects. Here, we investigate molecular mechanics-based models of passive membrane permeability and evaluate their performance against different types of experimental data, including parallel artificial membrane permeability assays (PAMPA), cell-based assays, in vivo measurements, and other in silico predictions. The experimental data sets we use in these tests are diverse, including peptidomimetics, congeneric series, and diverse FDA approved drugs. The physical models are not specifically trained for any of these data sets; rather, input parameters are based on standard molecular mechanics force fields, such as partial charges, and an implicit solvent model. A systematic approach is taken to analyze the contribution from each component in the physics-based permeability model. A primary factor in determining rates of passive membrane permeation is the conformation-dependent free energy of desolvating the molecule, and this measure alone provides good agreement with experimental permeability measurements in many cases. Other factors that improve agreement with experimental data include deionization and estimates of entropy losses of the ligand and the membrane, which lead to size-dependence of the permeation rate. PMID:22621168

  16. Involvement of sensory innervation in the skin of SOD1(G93A) ALS mice.

    PubMed

    Rubio, Miguel A; Herrando-Grabulosa, Mireia; Vilches, Jorge J; Navarro, Xavier

    2016-06-01

    Sensory alterations have been described in both amyotrophic lateral sclerosis (ALS) patients and mouse models. While involvement of intraepidermal and subepidermal axons has been shown in skin biopsies of ALS patients, it is unclear if the SOD1(G93A) mouse presents similar alterations. We analyzed the epidermal and dermal innervation, based on PGP9.5 immunostaining, of SOD1(G93A) mice at different stages. The results showed a marked reduction of intraepidermal nerve fibers, Meissner's corpuscles, and subepidermal nerve density already at 4 weeks. This loss of innervation progressed over time. Dermal axonal density decreased at a later stage of the disease. There was a gradient of axonal loss, with a more severe decline in the epidermis compared with deeper structures, indicating a distal axonal neuropathy as the mechanism of degeneration. These findings suggest that the analysis of the cutaneous sensory innervation may be an accessible and useful tool to assess the neurodegeneration process in motoneuron diseases. PMID:26880731

  17. Motoneuron differentiation of induced pluripotent stem cells from SOD1G93A mice.

    PubMed

    Yao, Xiao-Li; Ye, Cheng-Hui; Liu, Qiang; Wan, Jian-bo; Zhen, Jun; Xiang, Andy Peng; Li, Wei-Qiang; Wang, Yitao; Su, Huangxing; Lu, Xi-Lin

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder mainly affecting motor neurons. Mutations in superoxide dismutase-1 (SOD-1) account for about 20% of familial ALS patients. A robust supply of motoneurons carrying the mutated gene would help understand the causes of motoneuron death and develop new therapeutics for the disease. Here, we established induced pluripotent stem (iPS) cell lines from SOD1G93A mice and compared their potency in motoneuron generation with normal iPS cells and mouse embryonic stem cells (E14). Our results showed that iPS cells derived from SOD1G93A mice possessed the similar potency in neuronal differentiation to normal iPS cells and E14 cells and can be efficiently driven to motoneuron-like phenotype. These cells exhibited typical neuronal morphology, expressed key motoneuron markers, including ChAT and HB9, and generated repetitive trains of action potentials. Furthermore, these neurons highly expressed human SOD-1 and exhibited shorter neurites compared to controls. The present study provides evidence that ALS-iPS cells can be used as disease models in high-throughput screening and mechanistic studies due to their ability to efficiently differentiate into specific neuronal subtypes. PMID:23724084

  18. Test Cases for Reentry Survivability Modeling

    NASA Astrophysics Data System (ADS)

    Ailor, W.; Hallman, W.; Steckel, G.; Weaver, M.

    2012-01-01

    One approved approach for minimizing the long-term hazards posed by space debris is to reenter space hardware into the atmosphere at end-of-mission or to place hardware in an orbit with a relatively short lifetime. Selection of a short lifetime orbit vice a deorbited reentry into a safe area depends on predictions of the hazards posed by random reentry of the object. If the object is left in orbit, what is the casualty expectation associated with its eventual reentry? Clearly, having high confidence in reentry hazard prediction tools is important to this decision-making process and the final choice can have significant mission and cost impacts. This paper describes a set of test cases that can be used to validate reentry hazard models. The test cases were assembled from reentry cases where "known" and tracked objects reentered the atmosphere and debris from the reentries was subsequently found on the ground and was analyzed. The test cases include best estimates of the state, mass properties, and physical description of each object prior to reentry, the wind profile through which the debris fell (for one case), and the impact location and physical description of each surviving object. The report also summarizes results of metallurgical analyses conducted on surviving debris, which places limits on the maximum temperatures reached during reentry. Details on a specific reentry are included as an example.

  19. Ablative Rocket Deflector Testing and Computational Modeling

    NASA Technical Reports Server (NTRS)

    Allgood, Daniel C.; Lott, Jeffrey W.; Raines, Nickey

    2010-01-01

    A deflector risk mitigation program was recently conducted at the NASA Stennis Space Center. The primary objective was to develop a database that characterizes the behavior of industry-grade refractory materials subjected to rocket plume impingement conditions commonly experienced on static test stands. The program consisted of short and long duration engine tests where the supersonic exhaust flow from the engine impinged on an ablative panel. Quasi time-dependent erosion depths and patterns generated by the plume impingement were recorded for a variety of different ablative materials. The erosion behavior was found to be highly dependent on the material s composition and corresponding thermal properties. For example, in the case of the HP CAST 93Z ablative material, the erosion rate actually decreased under continued thermal heating conditions due to the formation of a low thermal conductivity "crystallization" layer. The "crystallization" layer produced near the surface of the material provided an effective insulation from the hot rocket exhaust plume. To gain further insight into the complex interaction of the plume with the ablative deflector, computational fluid dynamic modeling was performed in parallel to the ablative panel testing. The results from the current study demonstrated that locally high heating occurred due to shock reflections. These localized regions of shock-induced heat flux resulted in non-uniform erosion of the ablative panels. In turn, it was observed that the non-uniform erosion exacerbated the localized shock heating causing eventual plume separation and reversed flow for long duration tests under certain conditions. Overall, the flow simulations compared very well with the available experimental data obtained during this project.

  20. Experimentally testing the standard cosmological model

    SciTech Connect

    Schramm, D.N. Fermi National Accelerator Lab., Batavia, IL )

    1990-11-01

    The standard model of cosmology, the big bang, is now being tested and confirmed to remarkable accuracy. Recent high precision measurements relate to the microwave background; and big bang nucleosynthesis. This paper focuses on the latter since that relates more directly to high energy experiments. In particular, the recent LEP (and SLC) results on the number of neutrinos are discussed as a positive laboratory test of the standard cosmology scenario. Discussion is presented on the improved light element observational data as well as the improved neutron lifetime data. alternate nucleosynthesis scenarios of decaying matter or of quark-hadron induced inhomogeneities are discussed. It is shown that when these scenarios are made to fit the observed abundances accurately, the resulting conclusions on the baryonic density relative to the critical density, {Omega}{sub b}, remain approximately the same as in the standard homogeneous case, thus, adding to the robustness of the standard model conclusion that {Omega}{sub b} {approximately} 0.06. This latter point is the deriving force behind the need for non-baryonic dark matter (assuming {Omega}{sub total} = 1) and the need for dark baryonic matter, since {Omega}{sub visible} < {Omega}{sub b}. Recent accelerator constraints on non-baryonic matter are discussed, showing that any massive cold dark matter candidate must now have a mass M{sub x} {approx gt} 20 GeV and an interaction weaker than the Z{sup 0} coupling to a neutrino. It is also noted that recent hints regarding the solar neutrino experiments coupled with the see-saw model for {nu}-masses may imply that the {nu}{sub {tau}} is a good hot dark matter candidate. 73 refs., 5 figs.

  1. Thermal Model of the Promoted Combustion Test

    NASA Technical Reports Server (NTRS)

    Jones, Peter D.

    1996-01-01

    Flammability of metals in high pressure, pure oxygen environments, such as rocket engine turbopumps, is commonly evaluated using the Promoted Combustion Test (PCT). The PCT emphasizes the ability of an ignited material to sustain combustion, as opposed to evaluating the sample's propensity to ignite in the first place. A common arrangement is a rod of the sample material hanging in a chamber in which a high pressure, pure oxygen environment is maintained. An igniter of some energetically combusting material is fixed to the bottom of the rod and fired. This initiates combustion, and the sample burns and melts at its bottom tip. A ball of molten material forms, and this ball detaches when it grows too large to be supported by surface tension with the rod. In materials which do not sustain combustion, the combustion then extinguishes. In materials which do sustain combustion, combustion re-initiates from molten residue left on the bottom of the rod, and the melt ball burns and grows until it detaches again. The purpose of this work is development of a PCT thermal simulation model, detailing phase change, melt detachment, and the several heat transfer modes. Combustion is modeled by a summary rate equation, whose parameters are identified by comparison to PCT results. The sensitivity of PCT results to various physical and geometrical parameters is evaluated. The identified combustion parameters may be used in design of new PCT arrangements, as might be used for flammability assessment in flow-dominated environments. The Haynes 214 nickel-based superalloy, whose PCT results are applied here, burns heterogeneously (fuel and oxidizer are of different phases; combustion takes place on the fuel surface). Heterogeneous combustion is not well understood. (In homogeneous combustion, the metal vaporizes, and combustion takes place in an analytically treatable cloud above the surface). Thermal modeling in heterogeneous combustion settings provides a means for linking test

  2. Testing spherical evolution for modelling void abundances

    NASA Astrophysics Data System (ADS)

    Achitouv, Ixandra; Neyrinck, Mark; Paranjape, Aseem

    2015-08-01

    We compare analytical predictions of void volume functions to those measured from N-body simulations, detecting voids with the ZOBOV void finder. We push to very small, non-linear voids, below few Mpc radius, by considering the unsampled dark matter density field. We also study the case where voids are identified using haloes. We develop analytical formula for the void abundance of both the excursion set approach and the peaks formalism. These formulas are valid for random walks smoothed with a top-hat filter in real space, with a large class of realistic barrier models. We test the extent to which the spherical evolution approximation, which forms the basis of the analytical predictions, models the highly aspherical voids that occur in the cosmic web, and are found by a watershed-based algorithm such as ZOBOV. We show that the volume function returned by ZOBOV is quite sensitive to the choice of treatment of subvoids, a fact that has not been appreciated previously. For reasonable choices of subvoid exclusion, we find that the Lagrangian density δv of the ZOBOV voids - which is predicted to be a constant δv ≈ -2.7 in the spherical evolution model - is different from the predicted value, showing substantial scatter and scale dependence. This result applies to voids identified at z = 0 with effective radius between 1 and 10 h-1 Mpc. Our analytical approximations are flexible enough to give a good description of the resulting volume function; however, this happens for choices of parameter values that are different from those suggested by the spherical evolution assumption. We conclude that analytical models for voids must move away from the spherical approximation in order to be applied successfully to observations, and we discuss some possible ways forward.

  3. Computerized Classification Testing with the Rasch Model

    ERIC Educational Resources Information Center

    Eggen, Theo J. H. M.

    2011-01-01

    If classification in a limited number of categories is the purpose of testing, computerized adaptive tests (CATs) with algorithms based on sequential statistical testing perform better than estimation-based CATs (e.g., Eggen & Straetmans, 2000). In these computerized classification tests (CCTs), the Sequential Probability Ratio Test (SPRT) (Wald,…

  4. Designing Substantive Playing Tests- A Model.

    ERIC Educational Resources Information Center

    Byo, James L.

    2001-01-01

    Discusses the use of playing tests in music education, stating that the tests can be useful beyond assessment measurement. Describes how to create performance tests based upon the idea of an accomplished learner. Addresses how to give the tests and presents implications gleaned from field test results. (CMK)

  5. Testing of transition-region models: Test cases and data

    NASA Technical Reports Server (NTRS)

    Singer, Bart A.; Dinavahi, Surya; Iyer, Venkit

    1991-01-01

    Mean flow quantities in the laminar turbulent transition region and in the fully turbulent region are predicted with different models incorporated into a 3-D boundary layer code. The predicted quantities are compared with experimental data for a large number of different flows and the suitability of the models for each flow is evaluated.

  6. Experimental tests of the standard model.

    SciTech Connect

    Nodulman, L.

    1998-11-11

    The title implies an impossibly broad field, as the Standard Model includes the fermion matter states, as well as the forces and fields of SU(3) x SU(2) x U(1). For practical purposes, I will confine myself to electroweak unification, as discussed in the lectures of M. Herrero. Quarks and mixing were discussed in the lectures of R. Aleksan, and leptons and mixing were discussed in the lectures of K. Nakamura. I will essentially assume universality, that is flavor independence, rather than discussing tests of it. I will not pursue tests of QED beyond noting the consistency and precision of measurements of {alpha}{sub EM} in various processes including the Lamb shift, the anomalous magnetic moment (g-2) of the electron, and the quantum Hall effect. The fantastic precision and agreement of these predictions and measurements is something that convinces people that there may be something to this science enterprise. Also impressive is the success of the ''Universal Fermi Interaction'' description of beta decay processes, or in more modern parlance, weak charged current interactions. With one coupling constant G{sub F}, most precisely determined in muon decay, a huge number of nuclear instabilities are described. The slightly slow rate for neutron beta decay was one of the initial pieces of evidence for Cabbibo mixing, now generalized so that all charged current decays of any flavor are covered.

  7. Initial test results using the GEOS-3 engineering model altimeter

    NASA Technical Reports Server (NTRS)

    Hayne, G. S.; Clary, J. B.

    1977-01-01

    Data from a series of experimental tests run on the engineering model of the GEOS 3 radar altimeter using the Test and Measurement System (TAMS) designed for preflight testing of the radar altimeter are presented. These tests were conducted as a means of preparing and checking out a detailed test procedure to be used in running similar tests on the GEOS 3 protoflight model altimeter systems. The test procedures and results are also included.

  8. PTA test bed aircraft engine inlet model test report, revised

    NASA Technical Reports Server (NTRS)

    Hancock, J. P.

    1985-01-01

    The inlet duct test for the Propfan Testbed Assessment (PTA) program was completed in November 1984. The basic test duct was designed using the Lockheed QUADPAN computational code. Test objectives were to experimentally evaluate, modify as required, and eventually verify satisfactory performance as well as duct/engine compatibility. Measured total pressure recovery for the basic duct was 0.993 with no swirl and 0.989 for inflow with a 30 degree simulated swirl angle. This compared to a predicted recovery of 0.979 with no swirl. Measured circumferential distortion with swirl, based on a least-square curve fit of the data, was 0.204 compared to a maximum allowable value of 0.550. Other measured distortion parameters did as well or better relative to their respective maximum allowable values. The basic duct configuration with no refinements is recommended for the PTA inlet as a minimum cost installation.

  9. Testing constrained sequential dominance models of neutrinos

    NASA Astrophysics Data System (ADS)

    Björkeroth, Fredrik; King, Stephen F.

    2015-12-01

    Constrained sequential dominance (CSD) is a natural framework for implementing the see-saw mechanism of neutrino masses which allows the mixing angles and phases to be accurately predicted in terms of relatively few input parameters. We analyze a class of CSD(n) models where, in the flavour basis, two right-handed neutrinos are dominantly responsible for the ‘atmospheric’ and ‘solar’ neutrino masses with Yukawa couplings to ({ν }e,{ν }μ ,{ν }τ ) proportional to (0,1,1) and (1,n,n-2), respectively, where n is a positive integer. These coupling patterns may arise in indirect family symmetry models based on A 4. With two right-handed neutrinos, using a χ 2 test, we find a good agreement with data for CSD(3) and CSD(4) where the entire Pontecorvo-Maki-Nakagawa-Sakata mixing matrix is controlled by a single phase η, which takes simple values, leading to accurate predictions for mixing angles and the magnitude of the oscillation phase | {δ }{CP}| . We carefully study the perturbing effect of a third ‘decoupled’ right-handed neutrino, leading to a bound on the lightest physical neutrino mass {m}1{{≲ }}1 meV for the viable cases, corresponding to a normal neutrino mass hierarchy. We also discuss a direct link between the oscillation phase {δ }{CP} and leptogenesis in CSD(n) due to the same see-saw phase η appearing in both the neutrino mass matrix and leptogenesis.

  10. Effects of spaceflight on rhesus quadrupedal locomotion after return to 1G

    NASA Technical Reports Server (NTRS)

    Recktenwald, M. R.; Hodgson, J. A.; Roy, R. R.; Riazanski, S.; McCall, G. E.; Kozlovskaya, I.; Washburn, D. A.; Fanton, J. W.; Edgerton, V. R.; Rumbaugh, D. M. (Principal Investigator)

    1999-01-01

    Effects of spaceflight on Rhesus quadrupedal locomotion after return to 1G. Locomotor performance, activation patterns of the soleus (Sol), medial gastrocnemius (MG), vastus lateralis (VL), and tibialis anterior (TA) and MG tendon force during quadrupedal stepping were studied in adult Rhesus before and after 14 days of either spaceflight (n = 2) or flight simulation at 1G (n = 3). Flight simulation involved duplication of the spaceflight conditions and experimental protocol in a 1G environment. Postflight, but not postsimulation, electromyographic (EMG) recordings revealed clonus-like activity in all muscles. Compared with preflight, the cycle period and burst durations of the primary extensors (Sol, MG, and VL) tended to decrease postflight. These decreases were associated with shorter steps. The flexor (TA) EMG burst duration postflight was similar to preflight, whereas the burst amplitude was elevated. Consequently, the Sol:TA and MG:TA EMG amplitude ratios were lower following flight, reflecting a "flexor bias." Together, these alterations in mean EMG amplitudes reflect differential adaptations in motor-unit recruitment patterns of flexors and extensors as well as fast and slow motor pools. Shorter cycle period and burst durations persisted throughout the 20-day postflight testing period, whereas mean EMG returned to preflight levels by 17 days postflight. Compared with presimulation, the simulation group showed slight increases in the cycle period and burst durations of all muscles. Mean EMG amplitude decreased in the Sol, increased in the MG and VL, and was unchanged in the TA. Thus adaptations observed postsimulation were different from those observed postflight, indicating that there was a response unique to the microgravity environment, i.e., the modulations in the nervous system controlling locomotion cannot merely be attributed to restriction of movement but appear to be the result of changes in the interpretation of load-related proprioceptive feedback

  11. The WldS gene modestly prolongs survival in the SOD1G93A fALS mouse.

    PubMed

    Fischer, Lindsey R; Culver, Deborah G; Davis, Albert A; Tennant, Philip; Wang, Minsheng; Coleman, Michael; Asress, Seneshaw; Adalbert, Robert; Alexander, Guillermo M; Glass, Jonathan D

    2005-01-01

    The "slow Wallerian degeneration" (Wld(S)) gene is neuroprotective in numerous models of axonal degeneration. Axonal degeneration is an early feature of disease progression in the SOD1G93A mouse, a widely used model of familial amyotrophic lateral sclerosis (fALS). We crossed the Wld(S) mouse with the SOD1G93A mouse to investigate whether the Wld(S) gene could prolong survival and modify neuropathology in these mice. SOD/Wld(S) mice showed levels of motor axon loss similar to that seen in SOD1G93A mice. The presence of the Wld(S) gene, however, modestly prolonged survival and delayed denervation at the neuromuscular junction. Prolonged survival was more prominent in female mice and did not depend on whether animals were heterozygous or homozygous for the Wld(S) gene. We also report that SOD1G93A mice show significant degeneration of sensory axons during the course of disease, supporting previous data from humans demonstrating that ALS is not purely a motor disorder. PMID:15837585

  12. CCND1 G870A polymorphism and colorectal cancer risk: An updated meta-analysis

    PubMed Central

    XU, XIAO-MING; NI, XIAO-BING; YANG, GONG-LI; LUO, ZHI-GUO; NIU, YU-MING; SHEN, MING

    2016-01-01

    Molecular epidemiological studies have revealed a closer association between cyclin D1 (CCND1) polymorphism and the risk of colorectal cancer; however, the results were inconsistent. The aim of the present meta-analysis was to investigate the association between CCND1 G870A polymorphism and colorectal cancer risk. Online electronic databases (PubMed and Embase) were searched. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the association between CCND1 G870A polymorphism and the risk of colorectal cancer. In addition, heterogeneity, publication bias and sensitivity analysis were performed to guarantee the statistical power. In total, 23 published case-control studies with 6,320 patients and 8,252 controls were selected. Significantly increased risks were observed in four genetic models (A vs. G: OR=1.09, 95% CI=1.00–1.18, I2=54.3%; GA vs. GG: OR=1.13, 95% CI=1.04–1.24, I2=18.2%; AA vs. GG, OR=1.17: 95% CI=1.00–1.38, I2=52.5%; GA+AA vs. GG: OR=1.14, 95% CI=1.05–1.24, I2=33.8%). Similarly, significant associations were also identified in the stratified analysis in the cancer subtype of sporadic colorectal cancer (GA vs. GG: OR=1.21, 95% CI=1.04–1.42, I2=24.1%; GA+AA vs. GG: OR=1.18, 95% CI=1.02–1.37, I2=35.0%), Caucasian population (GA vs. GG, OR=1.14, 95% CI=1.02–1.28, I2=19.8%; GA+AA vs. GG, OR=1.14, 95% CI=1.02–1.27, I2=37.5%) and other subgroups of control design and genotyping type. The present updated meta-analysis suggested that CCND1 G870A may present an increased risk for developing colorectal cancer, particularly in sporadic colorectal cancer and a Caucasian population. PMID:27284448

  13. Correct CMOS IC defect models for quality testing

    NASA Technical Reports Server (NTRS)

    Soden, Jerry M.; Hawkins, Charles F.

    1993-01-01

    Leading edge, high reliability, and low escape CMOS IC test practices have now virtually removed the stuck-at fault model and replaced it with more defect-orientated models. Quiescent power supply current testing (I(sub DDQ)) combined with strategic use of high speed test patterns is the recommended approach to zero defect and high reliability testing goals. This paper reviews the reasons for the change in CMOS IC test practices and outlines an improved CMOS IC test methodology.

  14. Testing for Local Dependence in Rasch's Multiplicative Gamma Model for Speed Tests

    ERIC Educational Resources Information Center

    Jansen, Margo G. H.

    2007-01-01

    The author considers a latent trait model for the response time on a (set of) pure speed test(s), the multiplicative gamma model (MGM), which is based on the assumption that the test response times are approximately gamma distributed, with known index parameters and scale parameters depending on subject ability and test difficulty parameters. Like…

  15. Impacts of ABCB1 (G1199A) polymorphism on resistance, uptake, and efflux to steroid drugs.

    PubMed

    Peng, Rui; Zhang, Hong; Zhang, Ying; Wei, Dan-Yun

    2016-10-01

    1. P-glycoprotein (P-gp) substrates, including steroid drugs, involve in the inter-individual differences in resistant phenotype. This study was performed to evaluate whether G1199A polymorphism in ABCB1 gene can alter the sensitivity, accumulation, and transepithelial efflux to steroids in LLC-PK1 cells. 2. The stable recombinant LLC-PK1 cell lines transfected with ABCB1 1199G and ABCB1 1199A were used to assess the sensitivity, accumulation, and transepithelial permeability to steroids. 3. The cells transfected with 1199A allele displayed stronger resistance to aldosterone, dexamethasone, and cortisol (2.5-, 2.0-, and 1.6-fold, respectively) than cells overexpressing 1199G allele, while the two types of recombinant cells showed a similar resistance to corticosterone. The accumulation of aldosterone, dexamethasone, and cortisol in recombinant 1199A cells were significantly decreased when compared to 1199G cells (2.9-, 4.4-, and 3.9-fold, respectively). The net efflux ratios of P-gp-mediated aldosterone, dexamethasone, and cortisol in cells expressing 1199A allele were apparently greater than cells transfected with 1199G allele (3.3-, 3.5-, and 4.0-fold, respectively). 4. The impacts of ABCB1 (G1199A) single nucleotide polymorphism on the efflux of P-gp substrates presented as drug-specific. Overall, the transport ability of P-gp-dependent steroid drugs in recombinant model overexpressing variant 1199A allele is stronger in comparison to cells overexpressing wild-type 1199G allele. Therefore, the ABCB1 (G1199A) polymorphism may affect effective steroids concentration in target cells by regulating the drug transport and distribution. PMID:26822676

  16. Synthesis and Characterization of Five New F-bearing Basalt Reference Materials (Fba Glasses): Quantifying the Fluorine Content of the Basaltic Glass Standards BCR-2G, BHVO-2G. GSA-1G, GSC-1G, GSD-1G, GSE-1G, ML3B-G, KL2-G, and ALV-519-4

    NASA Astrophysics Data System (ADS)

    Guggino, S. N.; Hervig, R. L.

    2011-12-01

    -, detection of low-energy negative secondary ions (-5 kV), and a mass resolution that resolved 18OH. Homogeneity of the Fba glasses was established by both SIMS and EPMA. Glasses labeled Fba-2, -3. -4, and -5 pass statistical tests for homogeneity and may be used as EPMA or SIMS standards. SIMS calibration curves were constructed using the Fba glasses and other F standards of varying silica, iron, and sodium content, including Bt-3, F-phlog, NIST 610, KE-12, and UTR-2. The calibration curves revealed large matrix effects for the analysis of F by SIMS (~ 50%) between an Fba:Bt-3 curve and a high-silica glass:F-phlog curve. The Fba:Bt-3 calibration curve was used to determine the F contents (ppm ± 1 σ) of the following nine commonly used basaltic glass standards: BCR-2G (321 ± 15), BHVO-2G (297 ± 14), GSA-1G (7 ± 0.1), GSC-1G (9 ± 0.5), GSD-1G (18 ± 1), GSE-1G (154 ± 7), ML3B-G (47 ± 2), KL2-G (82 ± 4), ALV-519-4 (76 ± 4).

  17. Modeling Information Accumulation in Psychological Tests Using Item Response Times

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jörg-Tobias

    2015-01-01

    In this article, a latent trait model is proposed for the response times in psychological tests. The latent trait model is based on the linear transformation model and subsumes popular models from survival analysis, like the proportional hazards model and the proportional odds model. Core of the model is the assumption that an unspecified monotone…

  18. Association between cyclin D1 G870A polymorphism and hepatocellular carcinoma risk: a meta-analysis

    PubMed Central

    Luo, Tao; Chen, Jie; Liu, Jun-Jie; Li, Hang; You, Xue-Mei; Wang, Hong-Liang; Zhu, Shao-Liang; Li, Le-Qun

    2016-01-01

    Background Cyclin D1 (CCND1) G870A polymorphism may be associated with hepatocellular carcinoma (HCC) risk, but the results of previous studies were inconsistent. Available evidence was meta-analyzed to assess their potential association. Methods Databases PubMed, EMBASE, Cochrane Library, Web of Science, Chinese Biomedical Literature database, China National Knowledge Infrastructure, and Google Scholar were systematically searched. Meta-analyses were performed to investigate the association of G870A polymorphism with HCC risk by calculating odds ratios (ORs) and 95% confidence intervals (CIs) from the data of relevant case–control studies. Results Results of this meta-analysis of six case–control studies involving 1,030 cases and 1,683 controls indicate that G870A polymorphism was not associated with HCC risk in any of the five genetic models tested (recessive model: AA vs GG + AG: OR =1.38, 95% CI =0.95–2.00, P=0.09; dominant model: AG + AA vs GG: OR =1.38, 95% CI =0.87–2.20, P=0.17; homozygous model: AA vs GG: OR =1.60, 95% CI =0.87–2.94, P=0.13; heterozygous model: AG vs GG: OR =1.24, 95% CI =0.86–1.79, P=0.25; allelic model: A vs G: OR =1.30, 95% CI =0.95–1.80, P=0.10). Subgroup analyses according to ethnicity showing marginally significant association between this single nucleotide polymorphism and HCC risk indicate that G870A may be significantly associated with HCC risk in Caucasian populations (recessive model: AA vs GG + AG: OR =2.34, 95% CI =1.60–3.42, P<0.0001; dominant model: AG + AA vs GG: OR =2.44, 95% CI =1.19–4.97, P=0.01; homozygous model: AA vs GG: OR =3.42, 95% CI =1.80–6.50, P=0.0002; allelic model: A vs G: OR =2.06, 95% CI =1.31–3.24, P=0.002), but not in Asian populations. Conclusion Available evidence suggests that no significant association between G870A polymorphism and HCC risk was found in either total populations or Asian populations. However, significant association was found in Caucasian populations. These

  19. 46 CFR 54.01-10 - Steam-generating pressure vessels (modifies U-1(g)).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Steam-generating pressure vessels (modifies U-1(g)). 54... ENGINEERING PRESSURE VESSELS General Requirements § 54.01-10 Steam-generating pressure vessels (modifies U-1(g)). (a) Pressure vessels in which steam is generated are classed as “Unfired Steam Boilers” except...

  20. 46 CFR 54.01-10 - Steam-generating pressure vessels (modifies U-1(g)).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Steam-generating pressure vessels (modifies U-1(g)). 54... ENGINEERING PRESSURE VESSELS General Requirements § 54.01-10 Steam-generating pressure vessels (modifies U-1(g)). (a) Pressure vessels in which steam is generated are classed as “Unfired Steam Boilers” except...

  1. 46 CFR 54.01-10 - Steam-generating pressure vessels (modifies U-1(g)).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Steam-generating pressure vessels (modifies U-1(g)). 54... ENGINEERING PRESSURE VESSELS General Requirements § 54.01-10 Steam-generating pressure vessels (modifies U-1(g)). (a) Pressure vessels in which steam is generated are classed as “Unfired Steam Boilers” except...

  2. WELLTON GOVERNMENT CAMP, PERMANENT GARAGE TYPE 1G. PLAN, ELEVATIONS, AND ...

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

    WELLTON GOVERNMENT CAMP, PERMANENT GARAGE TYPE 1-G. PLAN, ELEVATIONS, AND SECTIONS. Drawing 50-308-4552, dated October 25, 1949. U.S. Department of the Interior, Bureau of Reclamation, Yuma, Arizona - Wellton-Mohawk Irrigation System, Permanent Garage Type 1-G, 30601 Wellton-Mohawk Drive, Wellton, Yuma County, AZ

  3. Model mount system for testing flutter

    NASA Technical Reports Server (NTRS)

    Farmer, M. G. (Inventor)

    1984-01-01

    A wind tunnel model mount system is disclosed for effectively and accurately determining the effects of attack and airstream velocity on a model airfoil or aircraft. The model mount system includes a rigid model attached to a splitter plate which is supported away from the wind tunnel wall several of flexible rods. Conventional instrumentation is employed to effect model rotation through a turntable and to record model flutter data as a function of the angle of attack versus dynamic pressure.

  4. Bayesian Test of Significance for Conditional Independence: The Multinomial Model

    NASA Astrophysics Data System (ADS)

    de Morais Andrade, Pablo; Stern, Julio; de Bragança Pereira, Carlos

    2014-03-01

    Conditional independence tests (CI tests) have received special attention lately in Machine Learning and Computational Intelligence related literature as an important indicator of the relationship among the variables used by their models. In the field of Probabilistic Graphical Models (PGM)--which includes Bayesian Networks (BN) models--CI tests are especially important for the task of learning the PGM structure from data. In this paper, we propose the Full Bayesian Significance Test (FBST) for tests of conditional independence for discrete datasets. FBST is a powerful Bayesian test for precise hypothesis, as an alternative to frequentist's significance tests (characterized by the calculation of the \\emph{p-value}).

  5. A Flexible Latent Trait Model for Response Times in Tests

    ERIC Educational Resources Information Center

    Ranger, Jochen; Kuhn, Jorg-Tobias

    2012-01-01

    Latent trait models for response times in tests have become popular recently. One challenge for response time modeling is the fact that the distribution of response times can differ considerably even in similar tests. In order to reduce the need for tailor-made models, a model is proposed that unifies two popular approaches to response time…

  6. ECOLOGICAL MODEL TESTING: VERIFICATION, VALIDATION OR NEITHER?

    EPA Science Inventory

    Consider the need to make a management decision about a declining animal population. Two models are available to help. Before a decision is made based on model results, the astute manager or policy maker may ask, "Do the models work?" Or, "Have the models been verified or validat...

  7. The dynamic modelling of a slotted test section

    NASA Technical Reports Server (NTRS)

    Gumas, G.

    1979-01-01

    A mathematical model of the wind tunnel dynamics was developed. The modelling techniques were restricted to the use of one dimensional unsteady flow. The dynamic characteristics of slotted test section incorporated into the model are presented.

  8. Test report SEPS solar array root section model

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The fabrication and test of a solar array functional root section model to verify preliminary array design concepts is presented. The root section model is full scale width and contains a model array blanket. The blanket contains 1/8 live electrical modules and the remainder contains solar cell mass simulators. A storable Astromast is used for array blanket extension and retraction. The model component and system assembly hardware, tests, and test results are described.

  9. Information Model for Machine-Tool-Performance Tests

    PubMed Central

    Lee, Y. Tina; Soons, Johannes A.; Donmez, M. Alkan

    2001-01-01

    This report specifies an information model of machine-tool-performance tests in the EXPRESS [1] language. The information model provides a mechanism for describing the properties and results of machine-tool-performance tests. The objective of the information model is a standardized, computer-interpretable representation that allows for efficient archiving and exchange of performance test data throughout the life cycle of the machine. The report also demonstrates the implementation of the information model using three different implementation methods.

  10. Optimization models for flight test scheduling

    NASA Astrophysics Data System (ADS)

    Holian, Derreck

    As threats around the world increase with nations developing new generations of warfare technology, the Unites States is keen on maintaining its position on top of the defense technology curve. This in return indicates that the U.S. military/government must research, develop, procure, and sustain new systems in the defense sector to safeguard this position. Currently, the Lockheed Martin F-35 Joint Strike Fighter (JSF) Lightning II is being developed, tested, and deployed to the U.S. military at Low Rate Initial Production (LRIP). The simultaneous act of testing and deployment is due to the contracted procurement process intended to provide a rapid Initial Operating Capability (IOC) release of the 5th Generation fighter. For this reason, many factors go into the determination of what is to be tested, in what order, and at which time due to the military requirements. A certain system or envelope of the aircraft must be assessed prior to releasing that capability into service. The objective of this praxis is to aide in the determination of what testing can be achieved on an aircraft at a point in time. Furthermore, it will define the optimum allocation of test points to aircraft and determine a prioritization of restrictions to be mitigated so that the test program can be best supported. The system described in this praxis has been deployed across the F-35 test program and testing sites. It has discovered hundreds of available test points for an aircraft to fly when it was thought none existed thus preventing an aircraft from being grounded. Additionally, it has saved hundreds of labor hours and greatly reduced the occurrence of test point reflight. Due to the proprietary nature of the JSF program, details regarding the actual test points, test plans, and all other program specific information have not been presented. Generic, representative data is used for example and proof-of-concept purposes. Apart from the data correlation algorithms, the optimization associated

  11. Type I Vs. Type II Cytokine Levels as a Function of SOD1 G93A Mouse Amyotrophic Lateral Sclerosis Disease Progression

    PubMed Central

    Jeyachandran, Amilia; Mertens, Benjamin; McKissick, Eric A.; Mitchell, Cassie S.

    2015-01-01

    Amyotrophic Lateral Sclerosis (ALS) is a fatal motoneuron disease that is characterized by the degradation of neurons throughout the central nervous system. Inflammation have been cited a key contributor to ALS neurodegeneration, but the timeline of cytokine upregulation remains unresolved. The goal of this study was to temporally examine the correlation between the varying levels of pro-inflammatory type I cytokines (IL-1β, IL-1α, IL-12, TNF-α, and GFAP) and anti-inflammatory type II cytokines (IL-4, IL-6, IL-10) throughout the progression of ALS in the SOD1 G93A mouse model. Cytokine level data from high copy SOD1 G93A transgenic mice was collected from 66 peer-reviewed studies. For each corresponding experimental time point, the ratio of transgenic to wild type (TG/WT) cytokine was calculated. One-way ANOVA and t-tests with Bonferonni correction were used to analyze the data. Meta-analysis was performed for four discrete stages: early, pre-onset, post-onset, and end stage. A significant increase in TG cytokine levels was found when compared to WT cytokine levels across the entire SOD1 G93A lifespan for majority of the cytokines. The rates of change of the individual cytokines, and type I and type II were not significantly different; however, the mean fold change of type I was expressed at significantly higher levels than type II levels across all stages with the difference between the means becoming more pronounced at the end stage. An overexpression of cytokines occurred both before and after the onset of ALS symptoms. The trend between pro-inflammatory type I and type II cytokine mean levels indicate a progressive instability of the dynamic balance between pro- and anti-inflammatory cytokines as anti-inflammatory cytokines fail to mediate the pronounced increase in pro-inflammatory cytokines. Very early immunoregulatory treatment is necessary to successfully interrupt ALS-induced neuroinflammation. PMID:26648846

  12. Test Driven Development of Scientific Models

    NASA Technical Reports Server (NTRS)

    Clune, Thomas L.

    2014-01-01

    Test-Driven Development (TDD), a software development process that promises many advantages for developer productivity and software reliability, has become widely accepted among professional software engineers. As the name suggests, TDD practitioners alternate between writing short automated tests and producing code that passes those tests. Although this overly simplified description will undoubtedly sound prohibitively burdensome to many uninitiated developers, the advent of powerful unit-testing frameworks greatly reduces the effort required to produce and routinely execute suites of tests. By testimony, many developers find TDD to be addicting after only a few days of exposure, and find it unthinkable to return to previous practices.After a brief overview of the TDD process and my experience in applying the methodology for development activities at Goddard, I will delve more deeply into some of the challenges that are posed by numerical and scientific software as well as tools and implementation approaches that should address those challenges.

  13. Versatile Support For Electromagnetic-Test Model

    NASA Technical Reports Server (NTRS)

    Wood, Richard M.; Ford, Eddie D.

    1994-01-01

    Supporting apparatus holds model for measurements of electromagnetic properties. Includes rigid swept strut, on end of which model oriented over range of angles. Designed to interfere minimally with electromagnetic measurements.

  14. Free-vibration characteristics of a large split-blanket solar array in a 1-g field

    NASA Technical Reports Server (NTRS)

    Shaker, F. J.

    1976-01-01

    Two methods for studying the free vibration characteristics of a large split blanket solar array in both a 0-g and a 1-g cantilevered configuration are presented. The 0-g configuration corresponds to an in-orbit configuration of the array; the 1-g configuration is a typical ground test configuration. The first method applies the equations of continuum mechanics to determine the mode shapes and frequencies of the array; the second method uses the Rayleigh-Ritz approach. In the Rayleigh-Ritz method the array displacements are represented by string modes and cantilevered beam modes. The results of this investigation are summarized by a series of graphs illustrating the effects of various array parameters on the mode shapes and frequencies of the system. The results of the two methods are also compared in tabular form.

  15. Model Based Analysis and Test Generation for Flight Software

    NASA Technical Reports Server (NTRS)

    Pasareanu, Corina S.; Schumann, Johann M.; Mehlitz, Peter C.; Lowry, Mike R.; Karsai, Gabor; Nine, Harmon; Neema, Sandeep

    2009-01-01

    We describe a framework for model-based analysis and test case generation in the context of a heterogeneous model-based development paradigm that uses and combines Math- Works and UML 2.0 models and the associated code generation tools. This paradigm poses novel challenges to analysis and test case generation that, to the best of our knowledge, have not been addressed before. The framework is based on a common intermediate representation for different modeling formalisms and leverages and extends model checking and symbolic execution tools for model analysis and test case generation, respectively. We discuss the application of our framework to software models for a NASA flight mission.

  16. Test Driven Development of Scientific Models

    NASA Technical Reports Server (NTRS)

    Clune, Thomas L.

    2012-01-01

    Test-Driven Development (TDD) is a software development process that promises many advantages for developer productivity and has become widely accepted among professional software engineers. As the name suggests, TDD practitioners alternate between writing short automated tests and producing code that passes those tests. Although this overly simplified description will undoubtedly sound prohibitively burdensome to many uninitiated developers, the advent of powerful unit-testing frameworks greatly reduces the effort required to produce and routinely execute suites of tests. By testimony, many developers find TDD to be addicting after only a few days of exposure, and find it unthinkable to return to previous practices. Of course, scientific/technical software differs from other software categories in a number of important respects, but I nonetheless believe that TDD is quite applicable to the development of such software and has the potential to significantly improve programmer productivity and code quality within the scientific community. After a detailed introduction to TDD, I will present the experience within the Software Systems Support Office (SSSO) in applying the technique to various scientific applications. This discussion will emphasize the various direct and indirect benefits as well as some of the difficulties and limitations of the methodology. I will conclude with a brief description of pFUnit, a unit testing framework I co-developed to support test-driven development of parallel Fortran applications.

  17. OAIS Functional Model Conformance Test: A Proposed Measurement

    ERIC Educational Resources Information Center

    Laughton, Paul

    2012-01-01

    Purpose: The purpose of this paper is to develop a test for data centres, repositories and archives to determine OAIS functional model conformance. The test developed was carried out among the World Data Centre (WDC) member data centres. The method used to develop the OAIS functional model conformance test is discussed, along with the test…

  18. Modulation of statolith mass and grouping in white clover (Trifolium repens) growth in 1-g, microgravity and on the clinostat

    NASA Technical Reports Server (NTRS)

    Smith, J. D.; Todd, P.; Staehelin, L. A.

    1997-01-01

    Current models of gravity perception in higher plants focus on the buoyant weight of starch-filled amyloplasts as the initial gravity signal susceptor (statolith). However, no tests have yet determined if statolith mass is regulated to increase or decrease gravity stimulus to the plant. To this end, the root caps of white clover (Trifolium repens) grown in three gravity environments with three different levels of gravity stimulation have been examined: (i) 1-g control with normal static gravistimulation, (ii) on a slow clinostat with constant gravistimulation, and (iii) in the stimulus-free microgravity aboard the Space Shuttle. Seedlings were germinated and grown in the BioServe Fluid Processing Apparatus and root cap structure was examined at both light and electron microscopic levels, including three-dimensional cell reconstruction from serial sections. Quantitative analysis of the electron micrographs demonstrated that the starch content of amyloplasts varied with seedling age but not gravity condition. It was also discovered that, unlike in starch storage amyloplasts, all of the starch granules of statolith amyloplasts were encompassed by a fine filamentous, ribosome-excluding matrix. From light micrographic 3-D cell reconstructions, the absolute volume, number, and positional relationships between amyloplasts showed (i) that individual amyloplast volume increased in microgravity but remained constant in seedlings grown for up to three days on the clinostat, (ii) the number of amyloplasts per cell remained unchanged in microgravity but decreased on the clinostat, and (iii) the three-dimensional positions of amyloplasts were not random. Instead amyloplasts in microgravity were grouped near the cell centers while those from the clinostat appeared more dispersed. Taken together, these observations suggest that changing gravity stimulation can elicit feedback control over statolith mass by changing the size, number, and grouping of amyloplasts. These results

  19. Surface characterization through shape oscillations of drops in microgravity and 1-g

    NASA Technical Reports Server (NTRS)

    Apfel, Robert E.; Holt, R. Glynn; Tian, Yuren; Shi, Tao; Zheng, Xiao-Yu

    1994-01-01

    The goal of these experiments is to determine the rheological properties of liquid drops of single or multiple components in the presence or absence of surface active materials by exciting drops into their quadrupole resonance and observing their free decay. The resulting data coupled with appropriate theory should give a better description of the physics of the underlying phenomena, providing a better foundation than earlier empirical results could. The space environment makes an idealized geometry available (spherical drops) so that theory and experiment can be properly compared, and allows a 'clean' environment, by which is meant an environment in which no solid surfaces come in contact with the drops during the test period. Moreover, by considering the oscillations of intentionally deformed drops in microgravity, a baseline is established for interpreting surface characterization experiments done on the ground by other groups and ours. Experiments performed on the United States Microgravity Laboratory Laboratory (USML-1) demonstrated that shape oscillation experiments could be performed over a wide parameter range, and with a variety of surfactant materials. Results, however, were compromised by an unexpected, slow drop tumbling, some problems with droplet injection, and the presence of bubbles in the drop samples. Nevertheless, initial data suggests that the space environment will be useful in providing baseline data that can serve to validate theory and permit quantitative materials characterization at 1-g.

  20. Similitude requirements and scaling relationships as applied to model testing

    NASA Technical Reports Server (NTRS)

    Wolowicz, C. H.; Brown, J. S., Jr.; Gilbert, W. P.

    1979-01-01

    The similitude requirements for the most general test conditions are presented. These similitude requirements are considered in relation to the scaling relationships, test technique, test conditions (including supersonic flow), and test objectives. Particular emphasis is placed on satisfying the various similitude requirements for incompressible and compressible flow conditions. For free flying models tests, the test velocities for incompressible flow are scaled from Froude number similitude requirements and those for compressible flow are scaled from Mach number similitude requirements. The limitations of various test techniques are indicated, with emphasis on the free flying model.

  1. Calpastatin inhibits motor neuron death and increases survival of hSOD1(G93A) mice.

    PubMed

    Rao, Mala V; Campbell, Jabbar; Palaniappan, Arti; Kumar, Asok; Nixon, Ralph A

    2016-04-01

    Amyotrophic lateral sclerosis (ALS) is a progressive motor neuron disease with a poorly understood cause and no effective treatment. Given that calpains mediate neurodegeneration in other pathological states and are abnormally activated in ALS, we investigated the possible ameliorative effects of inhibiting calpain over-activation in hSOD1(G93A) transgenic (Tg) mice in vivo by neuron-specific over-expression of calpastatin (CAST), the highly selective endogenous inhibitor of calpains. Our data indicate that over-expression of CAST in hSOD1(G93A) mice, which lowered calpain activation to levels comparable to wild-type mice, inhibited the abnormal breakdown of cytoskeletal proteins (spectrin, MAP2 and neurofilaments), and ameliorated motor axon loss. Disease onset in hSOD1(G93A) /CAST mice compared to littermate hSOD1(G93A) mice is delayed, which accounts for their longer time of survival. We also find that neuronal over-expression of CAST in hSOD1(G93A) transgenic mice inhibited production of putative neurotoxic caspase-cleaved tau and activation of Cdk5, which have been implicated in neurodegeneration in ALS models, and also reduced the formation of SOD1 oligomers. Our data indicate that inhibition of calpain with CAST is neuroprotective in an ALS mouse model. CAST (encoding calpastatin) inhibits hyperactivated calpain to prevent motor neuron disease operating through a cascade of events as indicated in the schematic, with relevance to amyotrophic lateral sclerosis (ALS). We propose that over-expression of CAST in motor neurons of hSOD1(G93A) mice inhibits activation of CDK5, breakdown of cytoskeletal proteins (NFs, MAP2 and Tau) and regulatory molecules (Cam Kinase IV, Calcineurin A), and disease-causing proteins (TDP-43, α-Synuclein and Huntingtin) to prevent neuronal loss and delay neurological deficits. In our experiments, CAST could also inhibit cleavage of Bid, Bax, AIF to prevent mitochondrial, ER and lysosome-mediated cell death mechanisms. Similarly

  2. A Functional Test Platform for the Community Land Model

    SciTech Connect

    Xu, Yang; Thornton, Peter E; King, Anthony Wayne; Steed, Chad A; Gu, Lianhong; Schuchart, Joseph

    2014-01-01

    A functional test platform is presented to create direct linkages between site measurements and the process-based ecosystem model within the Community Earth System Models (CESM). The platform consists of three major parts: 1) interactive user interfaces, 2) functional test model and 3) observational datasets. It provides much needed integration interfaces for both field experimentalists and ecosystem modelers to improve the model s representation of ecosystem processes within the CESM framework without large software overhead.

  3. Using the NPSS Environment to Model an Altitude Test Facility

    NASA Technical Reports Server (NTRS)

    Lavelle, Thomas M.; Owen, Albert K.; Huffman, Brian C.

    2013-01-01

    An altitude test facility was modeled using Numerical Propulsion System Simulation (NPSS). This altitude test facility model represents the most detailed facility model developed in the NPSS architecture. The current paper demonstrates the use of the NPSS system to define the required operating range of a component for the facility. A significant number of additional component models were easily developed to complete the model. Discussed in this paper are the additional components developed and what was done in the development of these components.

  4. Myo1g is an active player in maintaining cell stiffness in B-lymphocytes.

    PubMed

    López-Ortega, O; Ovalle-García, E; Ortega-Blake, I; Antillón, A; Chávez-Munguía, B; Patiño-López, G; Fragoso-Soriano, R; Santos-Argumedo, L

    2016-05-01

    B-lymphocytes are migrating cells that specialize in antigen presentation, antibody secretion, and endocytosis; these processes implicate the modulation of plasma membrane elasticity. Cell stiffness is a force generated by the interaction between the actin-cytoskeleton and the plasma membrane, which requires the participation of several proteins. These proteins include class I myosins, which are now considered to play a role in controlling membrane-cytoskeleton interactions. In this study, we identified the motor protein Myosin 1g (Myo1g) as a mediator of this phenomenon. The absence of Myo1g decreased the cell stiffness, affecting cell adhesion, cell spreading, phagocytosis, and endocytosis in B-lymphocytes. The results described here reveal a novel molecular mechanism by which Myo1g mediates and regulates cell stiffness in B-lymphocytes. © 2016 Wiley Periodicals, Inc. PMID:27106882

  5. Testing gravity-induced collapse models with torsion pendulums

    NASA Astrophysics Data System (ADS)

    Helou, Bassam; Wipf, Christopher; Chen, Yanbei

    2016-03-01

    Wavefunction collapse models have been proposed to resolve the measurement problem in QM. Some, , such as Diosi-Penrose model, are motivated by gravity. We first present the theory of such models, highlighting new results, such as fixing the only free paramater in the model. We then propose torsion pendulums as a promising optomechanical platform to test such models.

  6. Examining the Gm18 and m1G Modification Positions in tRNA Sequences

    PubMed Central

    Subramanian, Mayavan; Srinivasan, Thangavelu

    2014-01-01

    The tRNA structure contains conserved modifications that are responsible for its stability and are involved in the initiation and accuracy of the translation process. tRNA modification enzymes are prevalent in bacteria, archaea, and eukaryotes. tRNA Gm18 methyltransferase (TrmH) and tRNA m1G37 methyltransferase (TrmD) are prevalent and essential enzymes in bacterial populations. TrmH involves itself in methylation process at the 2'-OH group of ribose at the 18th position of guanosine (G) in tRNAs. TrmD methylates the G residue next to the anticodon in selected tRNA subsets. Initially, m1G37 modification was reported to take place on three conserved tRNA subsets (tRNAArg, tRNALeu, tRNAPro); later on, few archaea and eukaryotes organisms revealed that other tRNAs also have the m1G37 modification. The present study reveals Gm18, m1G37 modification, and positions of m1G that take place next to the anticodon in tRNA sequences. We selected extremophile organisms and attempted to retrieve the m1G and Gm18 modification bases in tRNA sequences. Results showed that the Gm18 modification G residue occurs in all tRNA subsets except three tRNAs (tRNAMet, tRNAPro, tRNAVal). Whereas the m1G37 modification base G is formed only on tRNAArg, tRNALeu, tRNAPro, and tRNAHis, the rest of the tRNAs contain adenine (A) next to the anticodon. Thus, we hypothesize that Gm18 modification and m1G modification occur irrespective of a G residue in tRNAs. PMID:25031570

  7. Oxygen consumption during cold exposure at 2.1 G in rats adapted to hypergravic fields

    NASA Technical Reports Server (NTRS)

    Horowitz, J.; Patterson, S.; Monson, C.

    1985-01-01

    The thermoregulation ability of rats exposed to various gravitational fields is examined. Male Sprague-Dawley rats were exposed to 22 C and 1 G, and 9 C and 2.1 G in experiment one, 1 G, 2.4 G, 5.8 G and 22 + or - 1.5 C in experiment two, and 1 G, 19-22 C, and 5 C in experiment three. It is observed that the core temperature in the control rats was 36.8 + or 0.4 C at 22C and 30.8 + or - 0.6 C at 9 C, and oxygen consumption dropped from 37 + or - 0.3 C core temperature at 22 C, 36.4 + or - 0.3 C at 9 C, 0.4 oxygen consumption was 8.18 + or - 0.9 ml/min at 22 C, and 14.2 + or - 0.4 ml/min at 9 C. The data from experiment two reveal that tail temperature in the control rats peaked at 2.4 G and at 5.8 G for the acclimated rats, and in experiment three a greater decrease in core temperature is detected in the 2.1-G rats. It is noted that prior acclimation to 2.1 G enhances the thermoregulation ability when exposed to the cold.

  8. Marker vaccine potential of a foot-and-mouth disease virus with a partial VP1 G-H loop deletion.

    PubMed

    Fowler, V L; Knowles, N J; Paton, D J; Barnett, P V

    2010-04-26

    Previous work in cattle and pigs demonstrated that protection against foot-and-mouth disease (FMD) could be achieved following vaccination with chimeric foot-and-mouth disease virus (FMDV) vaccines, in which the VP1 G-H loop had been substituted with that from another serotype. This indicated that the VP1 G-H loop may not be essential for the protection of natural hosts against FMDV. If this could be substantiated there would be potential to develop FMD marker vaccines, characterised by the absence of this region. Here, we investigate the serological responses to vaccination with a virus with a partial VP1 G-H loop deletion in order to determine the likelihood of achieving protection and the potential of this virus as a marker vaccine. Inactivated, oil adjuvanted, vaccines, consisting of chemically inactivated virus with or without a partially deleted VP1 G-H loop, were used to immunise cattle. Serum was collected on days 0, 7, 14 and 21 and antibody titres calculated using the virus neutralisation test (VNT) to estimate the likelihood of protection. We predict a good likelihood that cattle vaccinated with a vaccine characterised by a partial VP1 G-H loop would be protected against challenge with the same virus containing the VP1 G-H loop. We also present evidence on the potential of such a construct to act as a marker vaccine, when used in conjunction with a novel serological test. PMID:20199761

  9. Landing Procedure in Model Ditching Tests of Bf 109

    NASA Technical Reports Server (NTRS)

    Sottorf, W.

    1949-01-01

    The purpose of the model tests is to clarify the motions in the alighting on water of a land plane. After discussion of the model laws, the test method and test procedure are described. The deceleration-time-diagrams of the landing of a model of the Bf 109 show a high deceleration peek of greater than 20g which can be lowered to 4 to 6g by radiator cowling and brake skid.

  10. A Model for Random Student Drug Testing

    ERIC Educational Resources Information Center

    Nelson, Judith A.; Rose, Nancy L.; Lutz, Danielle

    2011-01-01

    The purpose of this case study was to examine random student drug testing in one school district relevant to: (a) the perceptions of students participating in competitive extracurricular activities regarding drug use and abuse; (b) the attitudes and perceptions of parents, school staff, and community members regarding student drug involvement; (c)…

  11. A Compromise Grading Model for Classroom Tests.

    ERIC Educational Resources Information Center

    Johanson, George A.

    Most educational measurement texts distinguish between norm-referenced (NR), or relative, methods of assigning letter grades to objective test scores, and criterion-referenced (CR), or absolute, methods. Both NR and CR approaches have serious limitations in typical classroom situations, and neither approach, in its pure form, may be entirely…

  12. Abnormal Intracellular Calcium Signaling and SNARE-Dependent Exocytosis Contributes to SOD1G93A Astrocyte-Mediated Toxicity in Amyotrophic Lateral Sclerosis

    PubMed Central

    Kawamata, Hibiki; Ng, Seng Kah; Diaz, Natalia; Burstein, Suzanne; Morel, Lydie; Osgood, Alexandra; Sider, Brittany; Higashimori, Haruki; Haydon, Philip G.

    2014-01-01

    Motor neurons are progressively and predominantly degenerated in ALS, which is not only induced by multiple intrinsic pathways but also significantly influenced by the neighboring glial cells. In particular, astrocytes derived from the SOD1 mutant mouse model of ALS or from human familial or sporadic ALS patient brain tissue directly induce motor neuron death in culture; however, the mechanisms of pathological astroglial secretion remain unclear. Here we investigated abnormal calcium homeostasis and altered exocytosis in SOD1G93A astrocytes. We found that purinergic stimulation induces excess calcium release from the ER stores in SOD1G93A astrocytes, which results from the abnormal ER calcium accumulation and is independent of clearance mechanisms. Furthermore, pharmacological studies suggested that store-operated calcium entry (SOCE), a calcium refilling mechanism responsive to ER calcium depletion, is enhanced in SOD1G93A astrocytes. We found that oxidant-induced increased S-glutathionylation and calcium-independent puncta formation of the ER calcium sensor STIM1 underlies the abnormal SOCE response in SOD1G93A astrocytes. Enhanced SOCE contributes to ER calcium overload in SOD1G93A astrocytes and excess calcium release from the ER during ATP stimulation. In addition, ER calcium release induces elevated ATP release from SOD1G93A astrocytes, which can be inhibited by the overexpression of dominant-negative SNARE. Selective inhibition of exocytosis in SOD1G93A astrocytes significantly prevents astrocyte-mediated toxicity to motor neurons and delays disease onset in SOD1G93A mice. Our results characterize a novel mechanism responsible for calcium dysregulation in SOD1G93A astrocytes and provide the first in vivo evidence that astrocyte exocytosis contributes to the pathogenesis of ALS. PMID:24501372

  13. Precipitation scavenging models: Sensitivities, tests, and applications

    SciTech Connect

    Hales, J.M.

    1991-07-01

    Multiphase'' atmospheric-chemistry models can be described as atmospheric-pollutant simulations that explicitly differentiate between physical phases in the atmosphere (.e.g., gas, cloud water, rain water, snow,...), and directly compute chemical transport and transformation behavior between and within each of these individual phases. Initially formulated for specific application to precipitation-scavenging analysis, many attributes of these models have become incorporated into the more general atmospheric-chemisty codes as well. During the past few years, several of these multiphase precipitation-scavenging models have been developed to the point where they can be applied, in a moderately straightforward fashion, by members of the extended atmospheric sciences community. This presentation provides a brief overview of several aspects of a number of these models, including their structure, their application, their sensitivities and uncertainty levels, their evaluation against field measurements, and their availability.

  14. Precipitation scavenging models: Sensitivities, tests, and applications

    SciTech Connect

    Hales, J.M.

    1991-07-01

    ``Multiphase`` atmospheric-chemistry models can be described as atmospheric-pollutant simulations that explicitly differentiate between physical phases in the atmosphere (.e.g., gas, cloud water, rain water, snow,...), and directly compute chemical transport and transformation behavior between and within each of these individual phases. Initially formulated for specific application to precipitation-scavenging analysis, many attributes of these models have become incorporated into the more general atmospheric-chemisty codes as well. During the past few years, several of these multiphase precipitation-scavenging models have been developed to the point where they can be applied, in a moderately straightforward fashion, by members of the extended atmospheric sciences community. This presentation provides a brief overview of several aspects of a number of these models, including their structure, their application, their sensitivities and uncertainty levels, their evaluation against field measurements, and their availability.

  15. Active control rotor model testing at Princeton's Rotorcraft Dynamics Laboratory

    NASA Technical Reports Server (NTRS)

    Mckillip, Robert M., Jr.

    1988-01-01

    A description of the model helicopter rotor tests currently in progress at Princeton's Rotorcraft Dynamics Laboratory is presented. The tests are designed to provide data for rotor dynamic modeling for use with active control system design. The model rotor to be used incoporates the capability for Individual Blade Control (IBC) or Higher Harmonic Control through the use of a standard swashplate on a three bladed hub. Sample results from the first series of tests are presented, along with the methodology used for state and parameter identification. Finally, pending experiments and possible research directions using this model and test facility are outlined.

  16. Beyond Testing: Empirical Models of Insurance Markets

    PubMed Central

    Einav, Liran; Finkelstein, Amy; Levin, Jonathan

    2011-01-01

    We describe recent advances in the empirical analysis of insurance markets. This new research proposes ways to estimate individual demand for insurance and the relationship between prices and insurer costs in the presence of adverse and advantageous selection. We discuss how these models permit the measurement of welfare distortions arising from asymmetric information and the welfare consequences of potential government policy responses. We also discuss some challenges in modeling imperfect competition between insurers and outline a series of open research questions. PMID:21572939

  17. Arrhythmogenic Right Ventricular Cardiomyopathy - 4 Swedish families with an associated PKP2 c.2146-1G>C variant

    PubMed Central

    Svensson, Anneli; Åström-Aneq, Meriam; Widlund, Kjerstin Ferm; Fluur, Christina; Green, Anna; Rehnberg, Malin; Gunnarsson, Cecilia

    2016-01-01

    In this study, the genotype-phenotype correlations in four unrelated families with a PKP2 c.2146-1G>C gene variant were studied. Our primary aim was to determine the carriers that fulfilled the arrhythmogenic right ventricular cardiomyopathy (ARVC) diagnostic criteria of 2010. Our secondary aim was to investigate whether any specific clinical characteristics can be attributed to this particular gene variant. Index patients were assessed using next generation ARVC panel sequencing technique and their family members were assessed by Sanger sequencing targeted at the PKP2 c.2146-1G>C variant. The gene variant carriers were offered a clinical follow-up, with evaluation based on the patient’s history and a standard set of non-invasive testing. The PKP2 c.2146-1G>C gene variant was found in 23 of 41 patients who underwent the examination. Twelve of the 19 family members showed “possible ARVC”. One with “borderline ARVC” and the rest with “definite ARVC” demonstrated re-polarization disturbances, but arrhythmia was uncommon. A lethal event occurred in a 14-year-old boy. In the present study, no definitive genotype-phenotype correlations were found, where the majority of the family members carrying the PKP2 c.2146-1G>C gene variant were diagnosed with “possible ARVC”. These individuals should be offered a long-term follow-up since they are frequently symptomless but still at risk for insidious sudden cardiac death due to ventricular arrhythmia. PMID:27335691

  18. Experimental tests of proton spin models

    SciTech Connect

    Ramsey, G.P. . Dept. of Physics Argonne National Lab., IL . High Energy Physics Div.)

    1989-11-03

    We have developed models for the spin-weighted quark and gluon distribution in a longitudinally polarized proton. The model parameters are determined from current algebra sum rules and polarized deep-inelastic scattering data. A number of different scenarios are presented for the fraction of spin carried the constituent parton distributions. A possible long-range experimental program is suggested for measuring various hard scattering processes using polarized lepton and proton beams. With the knowledge gained from these experiments, we can begin to understand the parton contributions to the proton spin. 28 refs., 5 figs.

  19. Testing prediction methods: Earthquake clustering versus the Poisson model

    USGS Publications Warehouse

    Michael, A.J.

    1997-01-01

    Testing earthquake prediction methods requires statistical techniques that compare observed success to random chance. One technique is to produce simulated earthquake catalogs and measure the relative success of predicting real and simulated earthquakes. The accuracy of these tests depends on the validity of the statistical model used to simulate the earthquakes. This study tests the effect of clustering in the statistical earthquake model on the results. Three simulation models were used to produce significance levels for a VLF earthquake prediction method. As the degree of simulated clustering increases, the statistical significance drops. Hence, the use of a seismicity model with insufficient clustering can lead to overly optimistic results. A successful method must pass the statistical tests with a model that fully replicates the observed clustering. However, a method can be rejected based on tests with a model that contains insufficient clustering. U.S. copyright. Published in 1997 by the American Geophysical Union.

  20. Proper selection of 1 g controls in simulated microgravity research as illustrated with clinorotated plant cell suspension cultures.

    PubMed

    Kamal, Khaled Y; Hemmersbach, Ruth; Medina, F Javier; Herranz, Raúl

    2015-04-01

    Understanding the physical and biological effects of the absence of gravity is necessary to conduct operations on space environments. It has been previously shown that the microgravity environment induces the dissociation of cell proliferation from cell growth in young seedling root meristems, but this source material is limited to few cells in each row of meristematic layers. Plant cell cultures, composed by a large and homogeneous population of proliferating cells, are an ideal model to study the effects of altered gravity on cellular mechanisms regulating cell proliferation and associated cell growth. Cell suspension cultures of Arabidopsis thaliana cell line (MM2d) were exposed to 2D-clinorotation in a pipette clinostat for 3.5 or 14 h, respectively, and were then processed either by quick freezing, to be used in flow cytometry, or by chemical fixation, for microscopy techniques. After long-term clinorotation, the proportion of cells in G1 phase was increased and the nucleolus area, as revealed by immunofluorescence staining with anti-nucleolin, was decreased. Despite the compatibility of these results with those obtained in real microgravity on seedling meristems, we provide a technical discussion in the context of clinorotation and proper 1 g controls with respect to suspension cultures. Standard 1 g procedure of sustaining the cell suspension is achieved by continuously shaking. Thus, we compare the mechanical forces acting on cells in clinorotated samples, in a control static sample and in the standard 1 g conditions of suspension cultures in order to define the conditions of a complete and reliable experiment in simulated microgravity with corresponding 1 g controls. PMID:26177849

  1. Proper selection of 1 g controls in simulated microgravity research as illustrated with clinorotated plant cell suspension cultures

    NASA Astrophysics Data System (ADS)

    Kamal, Khaled Y.; Hemmersbach, Ruth; Medina, F. Javier; Herranz, Raúl

    2015-04-01

    Understanding the physical and biological effects of the absence of gravity is necessary to conduct operations on space environments. It has been previously shown that the microgravity environment induces the dissociation of cell proliferation from cell growth in young seedling root meristems, but this source material is limited to few cells in each row of meristematic layers. Plant cell cultures, composed by a large and homogeneous population of proliferating cells, are an ideal model to study the effects of altered gravity on cellular mechanisms regulating cell proliferation and associated cell growth. Cell suspension cultures of Arabidopsis thaliana cell line (MM2d) were exposed to 2D-clinorotation in a pipette clinostat for 3.5 or 14 h, respectively, and were then processed either by quick freezing, to be used in flow cytometry, or by chemical fixation, for microscopy techniques. After long-term clinorotation, the proportion of cells in G1 phase was increased and the nucleolus area, as revealed by immunofluorescence staining with anti-nucleolin, was decreased. Despite the compatibility of these results with those obtained in real microgravity on seedling meristems, we provide a technical discussion in the context of clinorotation and proper 1 g controls with respect to suspension cultures. Standard 1 g procedure of sustaining the cell suspension is achieved by continuously shaking. Thus, we compare the mechanical forces acting on cells in clinorotated samples, in a control static sample and in the standard 1 g conditions of suspension cultures in order to define the conditions of a complete and reliable experiment in simulated microgravity with corresponding 1 g controls.

  2. A cautionary note on testing latent variable models

    PubMed Central

    Ropovik, Ivan

    2015-01-01

    The article tackles the practice of testing latent variable models. The analysis covered recently published studies from 11 psychology journals varying in orientation and impact. Seventy-five studies that matched the criterion of applying some of the latent modeling techniques were reviewed. Results indicate the presence of a general tendency to ignore the model test (χ2) followed by the acceptance of approximate fit hypothesis without detailed model examination yielding relevant empirical evidence. Due to reduced sensitivity of such a procedure to confront theory with data, there is an almost invariable tendency to accept the theoretical model. This absence of model test consequences, manifested in frequently unsubstantiated neglect of evidence speaking against the model, thus implies the perilous question of whether such empirical testing of latent structures (the way it is widely applied) makes sense at all. PMID:26594192

  3. A magnetorheological actuation system: test and model

    NASA Astrophysics Data System (ADS)

    John, Shaju; Chaudhuri, Anirban; Wereley, Norman M.

    2008-04-01

    Self-contained actuation systems, based on frequency rectification of the high frequency motion of an active material, can produce high force and stroke output. Magnetorheological (MR) fluids are active fluids whose rheological properties can be altered by the application of a magnetic field. By using MR fluids as the energy transmission medium in such hybrid devices, a valving system with no moving parts can be implemented and used to control the motion of an output cylinder shaft. The MR fluid based valves are configured in the form of an H-bridge to produce bi-directional motion in an output cylinder by alternately applying magnetic fields in the two opposite arms of the bridge. The rheological properties of the MR fluid are modeled using both Bingham plastic and bi-viscous models. In this study, the primary actuation is performed using a compact terfenol-D rod driven pump and frequency rectification of the rod motion is done using passive reed valves. The pump and reed valve configuration along with MR fluidic valves form a compact hydraulic actuation system. Actuator design, analysis and experimental results are presented in this paper. A time domain model of the actuator is developed and validated using experimental data.

  4. Simple Spreadsheet Models For Interpretation Of Fractured Media Tracer Tests

    EPA Science Inventory

    An analysis of a gas-phase partitioning tracer test conducted through fractured media is discussed within this paper. The analysis employed matching eight simple mathematical models to the experimental data to determine transport parameters. All of the models tested; two porous...

  5. The Development and Testing of a School Improvement Model

    ERIC Educational Resources Information Center

    Leithwood, Kenneth; Jantzi, Doris; McElheron-Hopkins, Charryn

    2006-01-01

    This multimethod study generated and tested a "best evidence" model of school improvement processes (SIP) capable of improving student achievement. Initially developed through the review of a comprehensive body of previous empirical research, the model was further refined through a 2, 5-year longitudinal study in 10 schools. A quantitative test of…

  6. Testing Structural Equation Models or Detection of Misspecifications?

    ERIC Educational Resources Information Center

    Saris, Willem E.; Satorra, Albert; van der Veld, William M.

    2009-01-01

    Assessing the correctness of a structural equation model is essential to avoid drawing incorrect conclusions from empirical research. In the past, the chi-square test was recommended for assessing the correctness of the model but this test has been criticized because of its sensitivity to sample size. As a reaction, an abundance of fit indexes…

  7. An Item Response Model for Characterizing Test Compromise.

    ERIC Educational Resources Information Center

    Segall, Daniel O.

    2002-01-01

    Developed an item response model for characterizing test-compromise that enables the estimation of item preview and score-gain distributions. In the approach, models parameters and posterior distributions are estimated by Markov Chain Monte Carlo procedures. Simulation study results suggest that when at least some test items are known to be…

  8. Tests Of Shear-Flow Model For Acoustic Impedance

    NASA Technical Reports Server (NTRS)

    Parrot, Tony L.; Watson, Willie R.; Jones, Michael G.

    1992-01-01

    Tests described in report conducted to validate two-dimensional shear-flow analytical model for determination of acoustic impedance of acoustic liner in grazing-incidence, grazing-flow environment by use of infinite-waveguide method. Tests successful for both upstream and downstream propagations. Work has potential for utility in testing of engine ducts in commercial aircraft.

  9. Testing Model with "Check Technique" for Physics Education

    ERIC Educational Resources Information Center

    Demir, Cihat

    2016-01-01

    As the number, date and form of the written tests are structured and teacher-oriented, it is considered that it creates fear and anxiety among the students. It has been found necessary and important to form a testing model which will keep the students away from the test anxiety and allows them to learn only about the lesson. For this study,…

  10. Item Response Theory Models for Performance Decline during Testing

    ERIC Educational Resources Information Center

    Jin, Kuan-Yu; Wang, Wen-Chung

    2014-01-01

    Sometimes, test-takers may not be able to attempt all items to the best of their ability (with full effort) due to personal factors (e.g., low motivation) or testing conditions (e.g., time limit), resulting in poor performances on certain items, especially those located toward the end of a test. Standard item response theory (IRT) models fail to…

  11. Statistical modeling for particle impact noise detection testing

    SciTech Connect

    Prairie, R.R. ); Zimmer, W.J. )

    1990-01-01

    Particle Impact Noise Detection (PIND) testing is widely used to test electronic devices for the presence of conductive particles which can cause catastrophic failure. This paper develops a statistical model based on the rate of particles contaminating the part, the rate of particles induced by the test vibration, the escape rate, and the false alarm rate. Based on data from a large number of PIND tests for a canned transistor, the model is shown to fit the observed results closely. Knowledge of the parameters for which this fit is made is important in evaluating the effectiveness of the PIND test procedure and for developing background judgment about the performance of the PIND test. Furthermore, by varying the input parameters to the model, the resulting yield, failure rate and percent fallout can be examined and used to plan and implement PIND test programs.

  12. Development of the GPM Observatory Thermal Vacuum Test Model

    NASA Technical Reports Server (NTRS)

    Yang, Kan; Peabody, Hume

    2012-01-01

    A software-based thermal modeling process was documented for generating the thermal panel settings necessary to simulate worst-case on-orbit flight environments in an observatory-level thermal vacuum test setup. The method for creating such a thermal model involved four major steps: (1) determining the major thermal zones for test as indicated by the major dissipating components on the spacecraft, then mapping the major heat flows between these components; (2) finding the flight equivalent sink temperatures for these test thermal zones; (3) determining the thermal test ground support equipment (GSE) design and initial thermal panel settings based on the equivalent sink temperatures; and (4) adjusting the panel settings in the test model to match heat flows and temperatures with the flight model. The observatory test thermal model developed from this process allows quick predictions of the performance of the thermal vacuum test design. In this work, the method described above was applied to the Global Precipitation Measurement (GPM) core observatory spacecraft, a joint project between NASA and the Japanese Aerospace Exploration Agency (JAXA) which is currently being integrated at NASA Goddard Space Flight Center for launch in Early 2014. From preliminary results, the thermal test model generated from this process shows that the heat flows and temperatures match fairly well with the flight thermal model, indicating that the test model can simulate fairly accurately the conditions on-orbit. However, further analysis is needed to determine the best test configuration possible to validate the GPM thermal design before the start of environmental testing later this year. Also, while this analysis method has been applied solely to GPM, it should be emphasized that the same process can be applied to any mission to develop an effective test setup and panel settings which accurately simulate on-orbit thermal environments.

  13. Multicomponent Equilibrium Models for Testing Geothermometry Approaches

    SciTech Connect

    Cooper, D. Craig; Palmer, Carl D.; Smith, Robert W.; McLing, Travis L.

    2013-02-01

    Geothermometry is an important tool for estimating deep reservoir temperature from the geochemical composition of shallower and cooler waters. The underlying assumption of geothermometry is that the waters collected from shallow wells and seeps maintain a chemical signature that reflects equilibrium in the deeper reservoir. Many of the geothermometers used in practice are based on correlation between water temperatures and composition or using thermodynamic calculations based a subset (typically silica, cations or cation ratios) of the dissolved constituents. An alternative approach is to use complete water compositions and equilibrium geochemical modeling to calculate the degree of disequilibrium (saturation index) for large number of potential reservoir minerals as a function of temperature. We have constructed several “forward” geochemical models using The Geochemist’s Workbench to simulate the change in chemical composition of reservoir fluids as they migrate toward the surface. These models explicitly account for the formation (mass and composition) of a steam phase and equilibrium partitioning of volatile components (e.g., CO2, H2S, and H2) into the steam as a result of pressure decreases associated with upward fluid migration from depth. We use the synthetic data generated from these simulations to determine the advantages and limitations of various geothermometry and optimization approaches for estimating the likely conditions (e.g., temperature, pCO2) to which the water was exposed in the deep subsurface. We demonstrate the magnitude of errors that can result from boiling, loss of volatiles, and analytical error from sampling and instrumental analysis. The estimated reservoir temperatures for these scenarios are also compared to conventional geothermometers. These results can help improve estimation of geothermal resource temperature during exploration and early development.

  14. Petroleum reservoir data for testing simulation models

    SciTech Connect

    Lloyd, J.M.; Harrison, W.

    1980-09-01

    This report consists of reservoir pressure and production data for 25 petroleum reservoirs. Included are 5 data sets for single-phase (liquid) reservoirs, 1 data set for a single-phase (liquid) reservoir with pressure maintenance, 13 data sets for two-phase (liquid/gas) reservoirs and 6 for two-phase reservoirs with pressure maintenance. Also given are ancillary data for each reservoir that could be of value in the development and validation of simulation models. A bibliography is included that lists the publications from which the data were obtained.

  15. Affective Robotics: Modelling and Testing Cultural Prototypes.

    PubMed

    A Wilson, Paul; Lewandowska-Tomaszczyk, Barbara

    2014-01-01

    If robots are to successfully interact with humans, they need to measure, quantify and respond to the emotions we produce. Similar to humans, the perceptual cue inputs to any modelling that allows this will be based on behavioural expression and body activity features that are prototypical of each emotion. However, the likely employment of such robots in different cultures necessitates the tuning of the emotion feature recognition system to the specific feature profiles present in these cultures. The amount of tuning depends on the relative convergence of the cross-cultural mappings between the emotion feature profiles of the cultures where the robots will be used. The GRID instrument and the cognitive corpus linguistics methodology were used in a contrastive study analysing a selection of behavioural expression and body activity features to compare the feature profiles of joy, sadness, fear and anger within and between Polish and British English. The intra-linguistic differences that were found in the profile of emotion features suggest that weightings based on this profile can be used in robotic modelling to create emotion-sensitive socially interacting robots. Our cross-cultural results further indicate that this profile of features needs to be tuned in robots to make them emotionally competent in different cultures. PMID:25484993

  16. Monoaminergic control of spinal locomotor networks in SOD1G93A newborn mice.

    PubMed

    Milan, Léa; Barrière, Grégory; De Deurwaerdère, Philippe; Cazalets, Jean-René; Bertrand, Sandrine S

    2014-01-01

    Mutations in the gene that encodes Cu/Zn-superoxide dismutase (SOD1) are the cause of approximately 20% of familial forms of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease characterized by the progressive loss of motor neurons. While ALS symptoms appear in adulthood, spinal motoneurons exhibit functional alterations as early as the embryonic and postnatal stages in the murine model of ALS, the SOD1 mice. Monoaminergic - i.e., dopaminergic (DA), serotoninergic (5-HT), and noradrenergic (NA) - pathways powerfully control spinal networks and contribute significantly to their embryonic and postnatal maturation. Alterations in monoaminergic neuromodulation during development could therefore lead to impairments in the motoneuronal physiology. In this study, we sought to determine whether the monoaminergic spinal systems are modified in the early stages of development in SOD1 mice. Using a post-mortem analysis by high performance liquid chromatography (HPLC), monoaminergic neuromodulators and their metabolites were quantified in the lumbar spinal cord of SOD1 and wild-type (WT) mice aged one postnatal day (P1) and P10. This analysis underscores an increased content of DA in the SOD1 lumbar spinal cord compared to that of WT mice but failed to reveal any modification of the other monoaminergic contents. In a next step, we compared the efficiency of the monoaminergic compounds in triggering and modulating fictive locomotion in WT and SOD1 mice. This study was performed in P1-P3 SOD1 mice and age-matched control littermates using extracellular recordings from the lumbar ventral roots in the in vitro isolated spinal cord preparation. This analysis revealed that the spinal networks of SOD1(G93A) mice could generate normal locomotor activity in the presence of NMA-5-HT. Interestingly, we also observed that SOD1 spinal networks have an increased sensitivity to NA compared to WT spinal circuits but exhibited similar DA responses. PMID:25071458

  17. Test plan for hydrologic modeling of protective barriers

    SciTech Connect

    Fayer, M.J.

    1990-03-01

    Pacific Northwest Laboratory prepared this test plan for the Model Applications and Validation Task of the Hanford Protective Barriers Program, which is managed by Westinghouse Hanford Company. The objectives of this plan are to outline the conceptual hydrologic model of protective barriers, discuss the available computer codes, describe the interrelationships between the modeling task and the other tasks of the Protective Barriers Program, present the barrier modeling tests, and estimate the schedule and costs of the hydrologic modeling task for planning purposes by the Protective Barriers Program. The purpose of the tests is to validate models that will be used to confirm the long-term performance of the barrier in minimizing drainage. A second purpose of the tests is to provide information to other parts of the Protective Barriers Program that require such information. 26 refs., 2 figs., 3 tabs.

  18. DKIST enclosure modeling and verification during factory assembly and testing

    NASA Astrophysics Data System (ADS)

    Larrakoetxea, Ibon; McBride, William; Marshall, Heather K.; Murga, Gaizka

    2014-08-01

    The Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST) is unique as, apart from protecting the telescope and its instrumentation from the weather, it holds the entrance aperture stop and is required to position it with millimeter-level accuracy. The compliance of the Enclosure design with the requirements, as of Final Design Review in January 2012, was supported by mathematical models and other analyses which included structural and mechanical analyses (FEA), control models, ventilation analysis (CFD), thermal models, reliability analysis, etc. During the Enclosure Factory Assembly and Testing the compliance with the requirements has been verified using the real hardware and the models created during the design phase have been revisited. The tests performed during shutter mechanism subsystem (crawler test stand) functional and endurance testing (completed summer 2013) and two comprehensive system-level factory acceptance testing campaigns (FAT#1 in December 2013 and FAT#2 in March 2014) included functional and performance tests on all mechanisms, off-normal mode tests, mechanism wobble tests, creation of the Enclosure pointing map, control system tests, and vibration tests. The comparison of the assumptions used during the design phase with the properties measured during the test campaign provides an interesting reference for future projects.

  19. Rare CFTR mutation 1525-1G>A in a Pakistani patient.

    PubMed

    Wahab, Abdul; Al Thani, G; Dawod, S T; Kambouris, M; Al Hamed, M

    2004-04-01

    Cystic fibrosis (CF) is rare in non-Caucasian populations, and in such populations little is known about the spectrum of mutations and polymorphisms in the cystic fibrosis transmembrane conductance (CFTR) gene. We report the detection of a very rare CFTR mutation 1525-1G>A in intron 9 in a 5-year-old Pakistani child with typical clinical features of CF. It remains to be seen whether mutation 1525-1G>A is characteristic of Pakistani ethnicity with CF or associated with severe phenotypic features. PMID:15088804

  20. Hydrostatic Tests of an Airship Model

    NASA Technical Reports Server (NTRS)

    1922-01-01

    An airship model made by the Goodyear Rubber Company was filled with water and suspended from a beam. The deformations of the envelope were studied under the following conditions: 1) both ballonets empty; 2) forward ballonets filled with air; 3) rear ballonets filled with air; and 4) both ballonets filled with air. Photographs were taken to record the deflections under each of these conditions, and a study was made to determine the minimum head of water necessary to maintain the longitudinal axis of the envelope under these conditions. It was concluded that any pressure sufficient to keep the airship full may be used. It appears that a pressure of one inch of water would provide a suitable factor of safety, and therefore it is the pressure that is recommended.

  1. Interferometric tests of Planckian quantum geometry models

    NASA Astrophysics Data System (ADS)

    Kwon, Ohkyung; Hogan, Craig J.

    2016-05-01

    The effect of Planck scale quantum geometrical effects on measurements with interferometers is estimated with standard physics, and with a variety of proposed extensions. It is shown that effects are negligible in standard field theory with canonically quantized gravity. Statistical noise levels are estimated in a variety of proposals for nonstandard metric fluctuations, and these alternatives are constrained using upper bounds on stochastic metric fluctuations from LIGO. Idealized models of several interferometer system architectures are used to predict signal noise spectra in a quantum geometry that cannot be described by a fluctuating metric, in which position noise arises from holographic bounds on directional information. Predictions in this case are shown to be close to current and projected experimental bounds.

  2. A mouse model for testing remyelinating therapies.

    PubMed

    Bai, C Brian; Sun, Sunny; Roholt, Andrew; Benson, Emily; Edberg, Dale; Medicetty, Satish; Dutta, Ranjan; Kidd, Grahame; Macklin, Wendy B; Trapp, Bruce

    2016-09-01

    Used in combination with immunomodulatory therapies, remyelinating therapies are a viable therapeutic approach for treating individuals with multiple sclerosis. Studies of postmortem MS brains identified greater remyelination in demyelinated cerebral cortex than in demyelinated brain white matter and implicated reactive astrocytes as an inhibitor of white matter remyelination. An animal model that recapitulates these phenotypes would benefit the development of remyelination therapeutics. We have used a modified cuprizone protocol that causes a consistent and robust demyelination of mouse white matter and cerebral cortex. Spontaneous remyelination occurred significantly faster in the cerebral cortex than in white matter and reactive astrocytes were more abundant in white matter lesions. Remyelination of white matter and cerebral cortex was therapeutically enhanced by daily injections of thyroid hormone triiodothyronine (T3). In summary, we describe an in vivo demyelination/remyelination paradigm that can be powered to determine efficacy of therapies that enhance white matter and cortical remyelination. PMID:27384502

  3. Interferometric tests of Planckian quantum geometry models

    DOE PAGESBeta

    Kwon, Ohkyung; Hogan, Craig J.

    2016-04-19

    The effect of Planck scale quantum geometrical effects on measurements with interferometers is estimated with standard physics, and with a variety of proposed extensions. It is shown that effects are negligible in standard field theory with canonically quantized gravity. Statistical noise levels are estimated in a variety of proposals for nonstandard metric fluctuations, and these alternatives are constrained using upper bounds on stochastic metric fluctuations from LIGO. Idealized models of several interferometer system architectures are used to predict signal noise spectra in a quantum geometry that cannot be described by a fluctuating metric, in which position noise arises from holographicmore » bounds on directional information. Lastly, predictions in this case are shown to be close to current and projected experimental bounds.« less

  4. Boron-10 ABUNCL Models of Fuel Testing

    SciTech Connect

    Siciliano, Edward R.; Lintereur, Azaree T.; Kouzes, Richard T.; Ely, James H.

    2013-10-01

    The Department of Energy Office of Nuclear Safeguards and Security (NA-241) is supporting the project Coincidence Counting With Boron-Based Alternative Neutron Detection Technology at Pacific Northwest National Laboratory (PNNL) for the development of a 3He proportional counter alternative neutron coincidence counter. The goal of this project is to design, build and demonstrate a system based upon 10B-lined proportional tubes in a configuration typical for 3He-based coincidence counter applications. This report provides results from MCNP simulations of the General Electric Reuter-Stokes Alternative Boron-Based Uranium Neutron Coincidence Collar (ABUNCL) active configuration model with fuel pins previously measured at Los Alamos National Laboratory. A comparison of the GE-ABUNCL simulations and simulations of 3He based UNCL-II active counter (the system for which the GE-ABUNCL was targeted to replace) with the same fuel pin assemblies is also provided.

  5. Using Laboratory Models to Test Treatment

    PubMed Central

    Adams, Lewis; O'Donnell, Carl R.; Gilman, Sean A.; Lansing, Robert W.; Schwartzstein, Richard M.

    2011-01-01

    Rationale: Opioids are commonly used to relieve dyspnea, but clinical data are mixed and practice varies widely. Objectives: Evaluate the effect of morphine on dyspnea and ventilatory drive under well-controlled laboratory conditions. Methods: Six healthy volunteers received morphine (0.07 mg/kg) and placebo intravenously on separate days (randomized, blinded). We measured two responses to a CO2 stimulus: (1) perceptual response (breathing discomfort; described by subjects as “air hunger”) induced by increasing partial pressure of end-tidal carbon dioxide (PetCO2) during restricted ventilation, measured with a visual analog scale (range, “neutral” to “intolerable”); and (2) ventilatory response, measured in separate trials during unrestricted breathing. Measurements and Main Results: We determined the PetCO2 that produced a 60% breathing discomfort rating in each subject before morphine (median, 8.5 mm Hg above resting PetCO2). At the same PetCO2 after morphine administration, median breathing discomfort was reduced by 65% of its pretreatment value; P < 0.001. Ventilation fell 28% at the same PetCO2; P < 0.01. The effect of morphine on breathing discomfort was not significantly correlated with the effect on ventilatory response. Placebo had no effect. Conclusions: (1) A moderate morphine dose produced substantial relief of laboratory dyspnea, with a smaller reduction of ventilation. (2) In contrast to an earlier laboratory model of breathing effort, this laboratory model of air hunger established a highly significant treatment effect consistent in magnitude with clinical studies of opioids. Laboratory studies require fewer subjects and enable physiological measurements that are difficult to make in a clinical setting. Within-subject comparison of the response to carefully controlled laboratory stimuli can be an efficient means to optimize treatments before clinical trials. PMID:21778294

  6. Thermophysical Property Measurements of Molten Semiconductors in 1-g and Reduced-g Condition

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu

    1999-01-01

    , these dispersed impurities in the melts tend to substantially modify the properties of pure semiconductors. Sample levitation done in a vacuum clearly helps maintain the sample purity. However, in the 1-g environment, all gravity caused effects such as convection, sedimentation and buoyancy are still present in the sample. In addition, large forces needed to levitate a sample in the presence of the gravity can cause additional flows in the melt. The use of the High Temperature Electrostatic Levitator (HTESL) for the present research is a recent development and little is known about the flows induced by the electrostatic forces. In this ground base program, we will define the limits of HTESL technology as various thermophysical properties of molten semiconductors are measured.

  7. Centrifuge model tests of rainfall-induced slope failures for the investigation of the initiation conditions

    NASA Astrophysics Data System (ADS)

    Matziaris, Vasileios; Marshall, Alec; Yu, Hai-Sui

    2015-04-01

    Rainfall-induced landslides are very common natural disasters which cause damage to properties and infrastructure and may result in the loss of human lives. These phenomena often take place in unsaturated soil slopes and are triggered by the saturation of the soil profile, due to rain infiltration, which leads to a loss of shear strength. The aim of this study is to determine rainfall thresholds for the initiation of landslides under different initial conditions. Model tests of rainfall-induced landslides are conducted in the Nottingham Centre for Geomechanics 50g-T geotechnical centrifuge. Initially unsaturated plane-strain slope models made with fine silica sand are prepared at varying densities at 1g and accommodated within a climatic chamber which provides controlled environmental conditions. During the centrifuge flight at 60g, rainfall events of varying intensity and duration are applied to the slope models causing the initiation of slope failure. The impact of soil state properties and rainfall characteristics on the landslide initiation process are discussed. The variation of pore water pressures within the slope before, during and after simulated rainfall events is recorded using miniature pore pressure transducers buried in the soil model. Slope deformation is determined by using a high-speed camera and digital image analysis techniques.

  8. Modal test and analysis: Multiple tests concept for improved validation of large space structure mathematical models

    NASA Technical Reports Server (NTRS)

    Wada, B. K.; Kuo, C-P.; Glaser, R. J.

    1986-01-01

    For the structural dynamic analysis of large space structures, the technology in structural synthesis and the development of structural analysis software have increased the capability to predict the dynamic characteristics of the structural system. The various subsystems which comprise the system are represented by various displacement functions; the displacement functions are then combined to represent the total structure. Experience has indicated that even when subsystem mathematical models are verified by test, the mathematical representations of the total system are often in error because the mathematical model of the structural elements which are significant when loads are applied at the interconnection points are not adequately verified by test. A multiple test concept, based upon the Multiple Boundary Condition Test (MBCT), is presented which will increase the accuracy of the system mathematical model by improving the subsystem test and test/analysis correlation procedure.

  9. Selecting Single Model in Combination Forecasting Based on Cointegration Test and Encompassing Test

    PubMed Central

    Jiang, Chuanjin; Zhang, Jing; Song, Fugen

    2014-01-01

    Combination forecasting takes all characters of each single forecasting method into consideration, and combines them to form a composite, which increases forecasting accuracy. The existing researches on combination forecasting select single model randomly, neglecting the internal characters of the forecasting object. After discussing the function of cointegration test and encompassing test in the selection of single model, supplemented by empirical analysis, the paper gives the single model selection guidance: no more than five suitable single models can be selected from many alternative single models for a certain forecasting target, which increases accuracy and stability. PMID:24892061

  10. Calculation of flight vibration levels of the AH-1G helicopter and correlation with existing flight vibration measurements

    NASA Technical Reports Server (NTRS)

    Ditaranto, R. A.; Sankewitsch, V.

    1989-01-01

    Boeing Helicopters, together with other U.S. Helicopter manufacturers, participated in a finite element applications program to give the United States a superior capability to utilize finite element analysis models in support of helicopter airframe design. The program was sponsored by the NASA Langley Research Center. Under this program, an activity was sponsored to evaluate existing analysis methods applicable to calculate coupled rotor-airframe vibrations. The helicopter used in this evaluation was the AH-1G helicopter. The results of the Boeing Helicopters efforts are summarized. The planned analytical procedure is reviewed. Changes to the planned procedure are discussed, and results of the correlation study are presented.