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Sample records for null genotype lack

  1. Glutathione S-transferase M1 null genotype: lack of association with tumour characteristics and survival in advanced breast cancer

    International Nuclear Information System (INIS)

    Lizard-Nacol, Sarab; Coudert, Bruno; Colosetti, Pascal; Riedinger, Jean-Marc; Fargeot, Pierre; Brunet-Lecomte, Patrick

    1999-01-01

    had no effect on disease-free or overall survival. The absence of hormone receptors (P = 0.002), the presence of a mutated p53 gene (P = 0.0098) and lack of response to primary chemotherapy (P = 0.0086) were the only factors associated with reduced disease-free or overall survival. GSTM1-null genotype alone had no effect on tumour characteristics and outcome of patients with advanced breast cancers. The lack of correlation of GSTM1 genotype with clinical tumour features, clinical response to chemotherapy and survival exclude a role for GSTM1 polymorphism as a prognostic factor in advanced breast cancer

  2. Impact of null genotypes of GSTT1 and GSTM1 with uterine leiomyoma risk in Iranian population.

    Science.gov (United States)

    Mostafavi, Salva Sadat; Ebrahimi, Ahmad; Sadat, Seyed Mehdi; Davari Tanha, Fatemeh; Aghasadeghi, Mohammad Reza; Bahramali, Golnaz; Abbasi Ranjbar, Parinaz; Sadeghifard, Vida; Javadi, Foozieh

    2016-04-01

    Few studies have investigated the role of the GSTM1 and GSTT1 genes in uterine leiomyoma. Therefore, in the current study the distribution of these genotypes in Iranian women and susceptibility to uterine leiomyoma was investigated. Blood samples of 50 patients with uterine leiomyoma and 50 healthy individual controls were collected in this cross-sectional study. Genomic DNA was extracted, and subsequently GSTM1 and GSTT1 null genotypes were detected by the Gap-polymerase chain reaction method. A total of 42% of patients appeared to lack GSTM1 enzyme activity due to the presence of an extended deletion (GSTM1 0/0 genotype), compared with 18% in a control group (odds ratio [OR], 3.56; 95% confidence interval [CI], 1.35-9.37; P leiomyoma and null GSTM1 and GSTT1 genotypes among Iranian patients. Our data support the involvement of GSTM1 and GSTT1 in uterine leiomyoma liability, and especially its role as a genetic factor in the occurrence of this disease. © 2016 Japan Society of Obstetrics and Gynecology.

  3. Combined glutathione S transferase M1/T1 null genotypes is associated with type 2 diabetes mellitus

    Science.gov (United States)

    POROJAN, MIHAI D.; BALA, CORNELIA; ILIES, ROXANA; CATANA, ANDREEA; POPP, RADU A.; DUMITRASCU, DAN L.

    2015-01-01

    Background Due to new genetic insights, a considerably large number of genes and polymorphic gene variants are screened and linked with the complex pathogenesis of type 2 diabetes (DM). Our study aimed to investigate the association between the two isoforms of the glutathione S-transferase genes (Glutathione S transferase isoemzyme type M1- GSTM1 and Glutathione S transferase isoemzyme type T1-GSTT1) and the prevalence of DM in the Northern Romanian population. Methods We conducted a cross-sectional, randomized, case-control study evaluating the frequency of GSTM1 and GSTT1 null alleles in patients diagnosed with DM. A total of 106 patients diagnosed with DM and 124 healthy controls were included in the study. GSTM1 and GSTT1 null alleles genotyping was carried out using Multiplex PCR amplification of relevant gene fragments, followed by gel electrophoresis analysis of the resulting amplicons. Results Molecular analysis did not reveal an increased frequency of the null GSTM1 and GSTT1 alleles (mutant genotypes) respectively in the DM group compared to controls (p=0.171, OR=1.444 CI=0.852–2.447; p=0.647, OR=0.854, CI=0.436–1.673). Nevertheless, the combined GSTM1/GSTT1 null genotypes were statistically significantly higher in DM patients compared to control subjects (p=0.0021, OR=0.313, CI=0.149–0.655) Conclusions The main finding of our study is that the combined, double GSTM1/GSTT1 null genotypes are to be considered among the polymorphic genetic risk factors for type 2 DM. PMID:26528065

  4. Identification of the GST-T1 and GST-M1 null genotypes using high resolution melting analysis.

    Science.gov (United States)

    Drobná, Zuzana; Del Razo, Luz Maria; Garcia-Vargas, Gonzalo; Sánchez-Ramírez, Blanca; González-Horta, Carmen; Ballinas-Casarrubias, Lourdes; Loomis, Dana; Stýblo, Miroslav

    2012-01-13

    Glutathione S-transferases, including GST-T1 and GST-M1, are known to be involved in the phase II detoxification pathways for xenobiotics as well as in the metabolism of endogenous compounds. Polymorphisms in these genes have been linked to an increased susceptibility to carcinogenesis and associated with risk factors that predispose to certain inflammatory diseases. In addition, GST-T1 and GST-M1 null genotypes have been shown to be responsible for interindividual variations in the metabolism of arsenic, a known human carcinogen. To assess the specific GST genotypes in the Mexican population chronically exposed to arsenic, we have developed a multiplex High Resolution Melting PCR (HRM-PCR) analysis using a LightCycler480 instrument. This method is based on analysis of the PCR product melting curve that discriminates PCR products according to their lengths and base sequences. Three pairs of primers that specifically recognize GST-T1, GST-M1, and β-globin, an internal control, to produce amplicons of different length were designed and combined with LightCycler480 High Resolution Melting Master Mix containing ResoLight, a completely saturating DNA dye. Data collected from melting curve analysis were evaluated using LightCycler480 software to determine specific melting temperatures of individual melting curves representing target genes. Using this newly developed multiplex HRM-PCR analysis, we evaluated GST-T1 and GST-M1 genotypes in 504 DNA samples isolated from the blood of individuals residing in Zimapan, Lagunera, and Chihuahua regions in Mexico. We found that the Zimapan and Lagunera populations have similar GST-T1 and GST-M1 genotype frequencies which differ from those of the Chihuahua population. In addition, 14 individuals have been identified as carriers of the double null genotype, i.e., null genotypes in both GST-T1 and GST-M1 genes. Although this procedure does not distinguish between biallelic (+/+) and monoallelic (+/-) genotypes, it can be used in an

  5. Lack of the nucleoside transporter ENT1 results in the Augustine-null blood type and ectopic mineralization.

    Science.gov (United States)

    Daniels, Geoff; Ballif, Bryan A; Helias, Virginie; Saison, Carole; Grimsley, Shane; Mannessier, Lucienne; Hustinx, Hein; Lee, Edmond; Cartron, Jean-Pierre; Peyrard, Thierry; Arnaud, Lionel

    2015-06-04

    The Augustine-negative alias At(a-) blood type, which seems to be restricted to people of African ancestry, was identified half a century ago but remains one of the last blood types with no known genetic basis. Here we report that a nonsynonymous single nucleotide polymorphism in SLC29A1 (rs45458701) is responsible for the At(a-) blood type. The resulting p.Glu391Lys variation in the last extracellular loop of the equilibrative nucleoside transporter 1 (ENT1; also called SLC29a1) is known not to alter its ability to transport nucleosides and nucleoside analog drugs. Furthermore, we identified 3 individuals of European ancestry who are homozygous for a null mutation in SLC29A1 (c.589+1G>C) and thus have the Augustine-null blood type. These individuals lacking ENT1 exhibit periarticular and ectopic mineralization, which confirms an important role for ENT1/SLC29A1 in human bone homeostasis as recently suggested by the skeletal phenotype of aging Slc29a1(-/-) mice. Our results establish Augustine as a new blood group system and place SLC29A1 as a new candidate gene for idiopathic disorders characterized with ectopic calcification/mineralization. © 2015 by The American Society of Hematology.

  6. Spdef null mice lack conjunctival goblet cells and provide a model of dry eye.

    Science.gov (United States)

    Marko, Christina K; Menon, Balaraj B; Chen, Gang; Whitsett, Jeffrey A; Clevers, Hans; Gipson, Ilene K

    2013-07-01

    Goblet cell numbers decrease within the conjunctival epithelium in drying and cicatrizing ocular surface diseases. Factors regulating goblet cell differentiation in conjunctival epithelium are unknown. Recent data indicate that the transcription factor SAM-pointed domain epithelial-specific transcription factor (Spdef) is essential for goblet cell differentiation in tracheobronchial and gastrointestinal epithelium of mice. Using Spdef(-/-) mice, we determined that Spdef is required for conjunctival goblet cell differentiation and that Spdef(-/-) mice, which lack conjunctival goblet cells, have significantly increased corneal surface fluorescein staining and tear volume, a phenotype consistent with dry eye. Microarray analysis of conjunctival epithelium in Spdef(-/-) mice revealed down-regulation of goblet cell-specific genes (Muc5ac, Tff1, Gcnt3). Up-regulated genes included epithelial cell differentiation/keratinization genes (Sprr2h, Tgm1) and proinflammatory genes (Il1-α, Il-1β, Tnf-α), all of which are up-regulated in dry eye. Interestingly, four Wnt pathway genes were down-regulated. SPDEF expression was significantly decreased in the conjunctival epithelium of Sjögren syndrome patients with dry eye and decreased goblet cell mucin expression. These data demonstrate that Spdef is required for conjunctival goblet cell differentiation and down-regulation of SPDEF may play a role in human dry eye with goblet cell loss. Spdef(-/-) mice have an ocular surface phenotype similar to that in moderate dry eye, providing a new, more convenient model for the disease. Copyright © 2013 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  7. Interaction between gas cooking and GSTM1 null genotype in bronchial responsiveness: results from the European Community Respiratory Health Survey

    Science.gov (United States)

    Amaral, André F S; Ramasamy, Adaikalavan; Castro-Giner, Francesc; Minelli, Cosetta; Accordini, Simone; Sørheim, Inga-Cecilie; Pin, Isabelle; Kogevinas, Manolis; Jõgi, Rain; Balding, David J; Norbäck, Dan; Verlato, Giuseppe; Olivieri, Mario; Probst-Hensch, Nicole; Janson, Christer; Zock, Jan-Paul; Heinrich, Joachim; Jarvis, Deborah L

    2014-01-01

    Background Increased bronchial responsiveness is characteristic of asthma. Gas cooking, which is a major indoor source of the highly oxidant nitrogen dioxide, has been associated with respiratory symptoms and reduced lung function. However, little is known about the effect of gas cooking on bronchial responsiveness and on how this relationship may be modified by variants in the genes GSTM1, GSTT1 and GSTP1, which influence antioxidant defences. Methods The study was performed in subjects with forced expiratory volume in one second at least 70% of predicted who took part in the multicentre European Community Respiratory Health Survey, had bronchial responsiveness assessed by methacholine challenge and had been genotyped for GSTM1, GSTT1 and GSTP1-rs1695. Information on the use of gas for cooking was obtained from interviewer-led questionnaires. Effect modification by genotype on the association between the use of gas for cooking and bronchial responsiveness was assessed within each participating country, and estimates combined using meta-analysis. Results Overall, gas cooking, as compared with cooking with electricity, was not associated with bronchial responsiveness (β=−0.08, 95% CI −0.40 to 0.25, p=0.648). However, GSTM1 significantly modified this effect (β for interaction=−0.75, 95% CI −1.16 to −0.33, p=4×10−4), with GSTM1 null subjects showing more responsiveness if they cooked with gas. No effect modification by GSTT1 or GSTP1-rs1695 genotypes was observed. Conclusions Increased bronchial responsiveness was associated with gas cooking among subjects with the GSTM1 null genotype. This may reflect the oxidant effects on the bronchi of exposure to nitrogen dioxide. PMID:24613990

  8. No contribution of GSTM1 and GSTT1 null genotypes to the risk of neutropenia due to benzene exposure in Southeastern Brazil

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    Carmen Silvia Passos Lima

    2009-01-01

    Full Text Available Exposure to benzene has been associated with haematological diseases such as neutropenia (NEB and acute myeloid leukaemia (AML. We tested whether the null genotypes of the GSTM1 and GSTT1 genes, involved in benzene inactivation, altered the risk for NEB in southeastern Brazil. Genomic DNA from 55 NEB patients and 330 controls was analysed by multiplex-polymerase chain reaction. The frequency of the GSTM1, GSTT1 and combined null genotypes was similar in patients and controls (GSTM1, 27.3% vs. 38.8%, p = 0.16; GSTT1, 25.5% vs. 19.7%, p = 0.24; GSTM1/GSTT1, 12.7% vs. 6.7%, p = 0.26; respectively. The distribution of genotype classes in NEB patients was similar to normal controls, suggesting that GSTM1 and GSTT1 null genotypes make no specific contribution to the risk of NEB. As the GSTM1 and GSTT1 null genotypes were previously associated with increased risk for AML in Brazil and elsewhere, we hypothesise that different thresholds of chemical exposure relative to distinct GSTM1 and GSTT1 genotypes may determine whether AML or NEB manifests in benzene exposed individuals from southeastern Brazil. Although indicative, our results still require support by prospective and large scale epidemiological studies, with rigorous assessment of daily chemical exposures and control of the possible contribution of other polymorphic genes involved in benzene metabolism.

  9. Glutathione S-transferase M1-null genotype as risk factor for SOS in oxaliplatin-treated patients with metastatic colorectal cancer.

    Science.gov (United States)

    Vreuls, C P H; Olde Damink, S W M; Koek, G H; Winstanley, A; Wisse, E; Cloots, R H E; van den Broek, M A J; Dejong, C H C; Bosman, F T; Driessen, A

    2013-02-19

    Oxaliplatin is used as a neo-adjuvant therapy in hepatic colorectal carcinoma metastasis. This treatment has significant side effects, as oxaliplatin is toxic to the sinusoidal endothelial cells and can induce sinusoidal obstruction syndrome (SOS), which is related to decreased overall survival. Glutathione has an important role in the defence system, catalysed by glutathione S-transferase (GST), including two non-enzyme producing polymorphisms (GSTM1-null and GSTT1-null). We hypothesise that patients with a non-enzyme producing polymorphism have a higher risk of developing toxic injury owing to oxaliplatin. In the nontumour-bearing liver, the presence of SOS was studied histopathologically. The genotype was determined by a semi-nested PCR. Thirty-two of the 55 (58%) patients showed SOS lesions, consisting of 27% mild, 22% moderate and 9% severe lesions. The GSTM1-null genotype was present in 25 of the 55 (46%). Multivariate analysis showed that the GSTM1-null genotype significantly correlated with the presence of (moderate-severe) SOS (P=0.026). The GSTM1-null genotype is an independent risk factor for SOS. This finding allows us, in association with other risk factors, to conceive a potential risk profile predicting whether the patient is at risk of developing SOS, before starting oxaliplatin, and subsequently might result in adjustment of treatment.

  10. The glutathione-S-transferase mu 1 (GSTM1) null genotype and increased neutrophil response to low-level ozone (0.06 ppm).

    Science.gov (United States)

    Background: Exposure of healthy young adults to 03 modulates immune cell biology in the airways and causes a significant increase in neutrophilic inflammation which can vary considerably in magnitude across individuals. The GSTM1null genotype modulates Oj-induced inflammation, bu...

  11. Females with paired occurrence of cancers in the UADT and genital region have a higher frequency of either Glutathione S-transferase M1/T1 null genotype

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    Jhavar Sameer G

    2005-03-01

    Full Text Available Abstract Upper Aero digestive Tract (UADT is the commonest site for the development of second cancer in females after primary cervical cancer. Glutathione S-transferase (GSTM1 and / or T1 null genotype modulates the risk of developing UADT cancer (primary as well as second cancer. The aim of this study was to evaluate the difference in GST null genotype frequencies in females with paired cancers in the UADT and genital region as compared to females with paired cancers in the UADT and non-genital region. Forty-nine females with a cancer in the UADT and another cancer (at all sites-genital and non-genital were identified from a database of patients with multiple primary neoplasms and were analyzed for the GSTM1 and T1 genotype in addition to known factors such as age, tobacco habits, alcohol habits and family history of cancer. Frequencies of GSTM1 null, GSTT1 null, and either GSTM1/T1 null were higher in females with paired occurrence of cancer in the UADT and genital site (54%, 33% and 75% respectively in comparison to females with paired occurrence of cancer in the UADT and non-genital sites (22%, 6% and 24% respectively. The significantly higher inherited frequency of either GSTM1/T1 null genotype in females with a paired occurrence of cancers in UADT and genital region (p = 0.01, suggests that these females are more susceptible to damage by carcinogens as compared to females who have UADT cancers in association with cancers at non-genital sites.

  12. The effect of cigarette smoke and arsenic exposure on urothelial carcinoma risk is modified by glutathione S-transferase M1 gene null genotype

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Chi-Jung [Department of Health Risk Management, College of Public Health, China Medical University, Taichung, Taiwan (China); Department of Medical Research, China Medical University Hospital, Taichung, Taiwan (China); Huang, Chao-Yuan; Pu, Yeong-Shiau [Department of Urology, National Taiwan University Hospital, Taipei, Taiwan (China); Shiue, Horng-Sheng [Department of Chinese Medicine, Chang Gung Memorial Hospital, Taipei, Taiwan (China); Su, Chien-Tien [Department of Family Medicine, Taipei Medical University Hospital, Taipei, Taiwan (China); Hsueh, Yu-Mei, E-mail: ymhsueh@tmu.edu.tw [Department of Public Health, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); School of Public Health, College of Public Health and Nutrition, Taipei Medical University, Taipei, Taiwan (China)

    2013-01-15

    Inter-individual variation in the metabolism of xenobiotics, caused by factors such as cigarette smoking or inorganic arsenic exposure, is hypothesized to be a susceptibility factor for urothelial carcinoma (UC). Therefore, our study aimed to evaluate the role of gene–environment interaction in the carcinogenesis of UC. A hospital-based case–control study was conducted. Urinary arsenic profiles were measured using high-performance liquid chromatography–hydride generator-atomic absorption spectrometry. Genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism technique. Information about cigarette smoking exposure was acquired from a lifestyle questionnaire. Multivariate logistic regression was applied to estimate the UC risk associated with certain risk factors. We found that UC patients had higher urinary levels of total arsenic, higher percentages of inorganic arsenic (InAs%) and monomethylarsonic acid (MMA%) and lower percentages of dimethylarsinic acid (DMA%) compared to controls. Subjects carrying the GSTM1 null genotype had significantly increased UC risk. However, no association was observed between gene polymorphisms of CYP1A1, EPHX1, SULT1A1 and GSTT1 and UC risk after adjustment for age and sex. Significant gene–environment interactions among urinary arsenic profile, cigarette smoking, and GSTM1 wild/null polymorphism and UC risk were observed after adjustment for potential risk factors. Overall, gene–environment interactions simultaneously played an important role in UC carcinogenesis. In the future, large-scale studies should be conducted using tag-SNPs of xenobiotic-metabolism-related enzymes for gene determination. -- Highlights: ► Subjects with GSTM1 null genotype had significantly increased UC risk. ► UC patients had poor arsenic metabolic ability compared to controls. ► GSTM1 null genotype may modify arsenic related UC risk.

  13. The effect of cigarette smoke and arsenic exposure on urothelial carcinoma risk is modified by glutathione S-transferase M1 gene null genotype

    International Nuclear Information System (INIS)

    Chung, Chi-Jung; Huang, Chao-Yuan; Pu, Yeong-Shiau; Shiue, Horng-Sheng; Su, Chien-Tien; Hsueh, Yu-Mei

    2013-01-01

    Inter-individual variation in the metabolism of xenobiotics, caused by factors such as cigarette smoking or inorganic arsenic exposure, is hypothesized to be a susceptibility factor for urothelial carcinoma (UC). Therefore, our study aimed to evaluate the role of gene–environment interaction in the carcinogenesis of UC. A hospital-based case–control study was conducted. Urinary arsenic profiles were measured using high-performance liquid chromatography–hydride generator-atomic absorption spectrometry. Genotyping was performed using a polymerase chain reaction-restriction fragment length polymorphism technique. Information about cigarette smoking exposure was acquired from a lifestyle questionnaire. Multivariate logistic regression was applied to estimate the UC risk associated with certain risk factors. We found that UC patients had higher urinary levels of total arsenic, higher percentages of inorganic arsenic (InAs%) and monomethylarsonic acid (MMA%) and lower percentages of dimethylarsinic acid (DMA%) compared to controls. Subjects carrying the GSTM1 null genotype had significantly increased UC risk. However, no association was observed between gene polymorphisms of CYP1A1, EPHX1, SULT1A1 and GSTT1 and UC risk after adjustment for age and sex. Significant gene–environment interactions among urinary arsenic profile, cigarette smoking, and GSTM1 wild/null polymorphism and UC risk were observed after adjustment for potential risk factors. Overall, gene–environment interactions simultaneously played an important role in UC carcinogenesis. In the future, large-scale studies should be conducted using tag-SNPs of xenobiotic-metabolism-related enzymes for gene determination. -- Highlights: ► Subjects with GSTM1 null genotype had significantly increased UC risk. ► UC patients had poor arsenic metabolic ability compared to controls. ► GSTM1 null genotype may modify arsenic related UC risk.

  14. Mannose-binding lectin genotypes: lack of association with susceptibility to thoracic empyema

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    Moore Catrin E

    2010-01-01

    Full Text Available Abstract Background The role of the innate immune protein mannose-binding lectin (MBL in host defence against severe respiratory infection remains controversial. Thoracic empyema is a suppurative lung infection that arises as a major complication of pneumonia and is associated with a significant mortality. Although the pathogenesis of thoracic empyema is poorly understood, genetic susceptibility loci for this condition have recently been identified. The possible role of MBL genotypic deficiency in susceptibility to thoracic empyema has not previously been reported. Methods To investigate this further we compared the frequencies of the six functional MBL polymorphisms in 170 European individuals with thoracic empyema and 225 healthy control individuals. Results No overall association was observed between MBL genotypic deficiency and susceptibility to thoracic empyema (2 × 2 Chi square = 0.02, P = 0.87. Furthermore, no association was seen between MBL deficiency and susceptibility to the Gram-positive or pneumococcal empyema subgroups. MBL genotypic deficiency did not associate with progression to death or requirement for surgery. Conclusions Our results suggest that MBL genotypic deficiency does not associate with susceptibility to thoracic empyema in humans.

  15. KIR-HLA genotypes in HIV-infected patients lacking immunological recovery despite effective antiretroviral therapy.

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    Alessandro Soria

    Full Text Available BACKGROUND: In HIV-infected individuals, mechanisms underlying unsatisfactory immune recovery during effective combination antiretroviral therapy (cART have yet to be fully understood. We investigated whether polymorphism of genes encoding immune-regulating molecules, such as killer immunoglobulin-like receptors (KIR and their ligands class I human leukocyte antigen (HLA, could influence immunological response to cART. METHODS: KIR and HLA frequencies were analyzed in 154 HIV-infected and cART-treated patients with undetectable viral load divided into two groups: 'immunological non responders' (INR, N = 50, CD4(+ T-cell count 350/mm(3. Molecular KIR were typed using polymerase chain reaction-based genotyping. Comparisons were adjusted for baseline patient characteristics. RESULTS: The frequency of KIR2DL3 allele was significantly higher in FR than in INR (83.7% vs. 62%, P = 0.005. The functional compound genotype HLA-C1(+/KIR2DL3(+, even at multivariable analysis, when adjusted for nadir CD4(+ T-cell count, was associated with reduced risk of INR status: odds ratio (95% Confidence Intervals 0.34 (0.13-0.88, P = 0.03. CONCLUSIONS: Reduced presence of the inhibitory KIR2DL3 genotype detected in INR might provoke an imbalance in NK function, possibly leading to increased immune activation, impaired killing of latently infected cells, and higher proviral burden. These factors would hinder full immune recovery during therapy.

  16. Lack of influence of CYP2D6 genotype on the clearance of (R)-, (S)- and racemic-methadone

    DEFF Research Database (Denmark)

    Coller, J K; Joergensen, C; Foster, D J R

    2007-01-01

    OBJECTIVE: To investigate the influence of CYP2D6 genotype on the oral clearance of (R)-, (S)- and rac-methadone. METHODS: In this retrospective study, CYP2D6 genotypes were identified in 56 methadone maintained subjects. Plasma concentrations of (R)-, (S)- and rac-methadone were determined by st...

  17. Strategy and model building in the fourth dimension: a null model for genotype x age interaction as a Gaussian stationary stochastic process.

    Science.gov (United States)

    Diego, Vincent P; Almasy, Laura; Dyer, Thomas D; Soler, Júlia M P; Blangero, John

    2003-12-31

    Using univariate and multivariate variance components linkage analysis methods, we studied possible genotype x age interaction in cardiovascular phenotypes related to the aging process from the Framingham Heart Study. We found evidence for genotype x age interaction for fasting glucose and systolic blood pressure. There is polygenic genotype x age interaction for fasting glucose and systolic blood pressure and quantitative trait locus x age interaction for a linkage signal for systolic blood pressure phenotypes located on chromosome 17 at 67 cM.

  18. Neutralizing antibodies in patients with chronic hepatitis C, genotype 1, against a panel of genotype 1 culture viruses: lack of correlation to treatment outcome.

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    Jannie Pedersen

    Full Text Available The correlation of neutralizing antibodies to treatment outcome in patients with chronic hepatitis C virus (HCV infection has not been established. The aim of this study was to determine whether neutralizing antibodies could be used as an outcome predictor in patients with chronic HCV, genotype 1, infection treated with pegylated interferon-α and ribavirin. Thirty-nine patients with chronic hepatitis C, genotype 1a or 1b, with either sustained virologic response (n = 23 or non-sustained virologic response (n = 16 were enrolled. Samples taken prior to treatment were tested for their ability to neutralize 6 different HCV genotype 1 cell culture recombinants (1a: H77/JFH1, TN/JFH1, DH6/JFH1; 1b: J4/JFH1, DH1/JFH1, DH5/JFH1. The results were expressed as the highest dilution yielding 50% neutralization (NAb50-titer. We observed no genotype or subtype specific differences in NAb50-titers between patients with chronic HCV infection with and without sustained virologic response when tested against any of the included culture viruses. However, NAb50-titers varied significantly with a mean reciprocal NAb50-titer of 800 (range: 100-6400 against DH6/JFH1 compared to a mean NAb50-titer of 50 (range: <50-400 against all other included isolates. Subsequent studies demonstrated that the efficient neutralization of DH6/JFH1 could be linked to engineered adaptive mutations in the envelope-2 protein. In analysis of envelope 1 and 2 sequences of HCV, recovered from a subset of patients, we observed no apparent link between relatedness of patient sequences with culture viruses used and the corresponding neutralization results. In conclusion, pre-treatment levels of neutralizing antibodies against HCV genotype 1 isolates could not predict treatment outcome in patients with chronic HCV infection. High neutralization susceptibility of DH6/JFH1 could be correlated with adaptive envelope mutations previously highlighted as important for neutralization. Our

  19. Lack of association of DRD4 exon 3 VNTR genotype with reactivity to dynamic smoking cues in movies

    NARCIS (Netherlands)

    Lochbühler, K.C.; Verhagen, M.; Munafò, M.R.; Engels, R.C.M.E.

    2013-01-01

    Background: The objective of the present study was first to examine whether dynamic smoking cues in movies trigger craving, and second to explore whether the DRD4 48 bp variable number of tandem repeat (VNTR) exon 3 genotype modifies this relationship. Using an experimental design, daily adult

  20. Lack of detection of host associated differences in Newcastle disease viruses of genotype VIId isolated from chickens and geese

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    Wang Yuyang

    2012-09-01

    Full Text Available Abstract Background The goose is usually considered to be resistant even to strains of Newcastle disease virus (NDV that are markedly virulent for chickens. However, ND outbreaks have been frequently reported in goose flocks in China since the late 1990s with the concurrent emergence of genotype VIId NDV in chickens. Although the NDVs isolated from both chickens and geese in the past 15 years have been predominantly VIId viruses, published data comparing goose- and chicken-originated ND viruses are scarce and controversial. Results In this paper, we compared genotype VIId NDVs originated from geese and chickens genetically and pathologically. Ten entire genomic sequences and 329 complete coding sequences of individual genes from genotype VIId NDVs of both goose- and chicken-origin were analyzed. We then randomly selected two goose-originated and two chicken-originated VIId NDVs and compared their pathobiology in both geese and chickens in vivo and in vitro with genotype IV virus Herts/33 as a reference. The results showed that all the VIId NDVs either from geese or from chickens shared high sequence homology and characteristic amino acid substitutions and clustered together in phylogenetic trees. In addition, geese and chickens infected by goose or chicken VIId viruses manifested very similar pathological features distinct from those of birds infected with Herts/33. Conclusions There is no genetic or phenotypic difference between genotype VIId NDVs originated from geese and chickens. Therefore, no species-preference exists for either goose or chicken viruses and more attention should be paid to the trans-species transmission of VIId NDVs between geese and chickens for the control and eradication of ND.

  1. Lack of genetic variation in tree ring delta13C suggests a uniform, stomatally-driven response to drought stress across Pinus radiata genotypes.

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    Rowell, Douglas M; Ades, Peter K; Tausz, Michael; Arndt, Stefan K; Adams, Mark A

    2009-02-01

    We assessed the variation in delta(13)C signatures of Pinus radiata D. Don stemwood taken from three genetic trials in southern Australia. We sought to determine the potential of using delta(13)C signatures as selection criteria for drought tolerance. Increment cores were taken from P. radiata and were used to determine the basal area increment and the delta(13)C signature of extracted cellulose. Both growth increment and cellulose delta(13)C were affected by water availability. Growth increment and delta(13)C were negatively correlated suggesting that growth was water-limited. While there was significant genetic variation in growth, there was no significant genetic variation in cellulose delta(13)C of tree rings. This suggests that different genotypes of P. radiata display significant differences in growth and yet respond similarly to drought stress. The delta(13)C response to drought stress was more due to changes in stomatal conductance than to the variation in photosynthetic capacity, and this may explain the lack of genetic variation in delta(13)C. The lack of genetic variation in cellulose delta(13)C of tree rings precludes its use as a selection criterion for drought tolerance among P. radiata genotypes.

  2. Lack of evidence to support the association of a single IL28B genotype SNP rs12979860 with the HTLV-1 clinical outcomes and proviral load

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    Sanabani Sabri Saeed

    2012-12-01

    Full Text Available Abstract Background The Interleukin 28B (IL28B rs12979860 polymorphisms was recently reported to be associated with the human T-cell leukemia virus type 1 (HTLV-1 proviral load (PvL and the development of the HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP. Methods In an attempt to examine this hypothesis, we assessed the association of the rs12979860 genotypes with HTLV-1 PvL levels and clinical status in 112 unrelated Brazilian subjects (81 HTLV-1 asymptomatic carriers, 24 individuals with HAM/TSP and 7 with Adult T cell Leukemia/Lymphoma (ATLL. Results All 112 samples were successfully genotyped and their PvLs compared. Neither the homozygote TT nor the heterozygote CT mutations nor the combination genotypes (TT/CT were associated with a greater PvL. We also observed no significant difference in allele distribution between asymptomatic carriers and patients with HTLV-1 associated HAM/TSP. Conclusions Our study failed to support the previously reported positive association between the IL28B rs12979860 polymorphisms and an increased risk of developing HAM/TSP in the Brazilian population.

  3. Lack of evidence of HPV etiology of prostate cancer following radical surgery and higher frequency of the Arg/Pro genotype in turkish men with prostate cancer

    Directory of Open Access Journals (Sweden)

    Merve Aydin

    Full Text Available ABSTRACT Objectives The aim of this study was to assess the possible role of HPV in the development of prostate cancer (PCa and investigate the distribution of the p53 codon 72 polymorphism in PCa in a Turkish population. Materials and methods A total of 96 tissues, which had been obtained using a radical surgery method, formalin-fixed and parafin-embedded, were used in this study. The study group consisted of 60 PCa tissues (open radical prostatectomy and the control group contained 36 benign prostatic hyperplasia tissues (BPH (transvesical open prostatectomy. The presence of HPV and the p53 codon 72 polymorphism was investigated in both groups using real-time PCR and pyrosequencing. Results The results of the real-time PCR showed no HPV DNA in any of the 36 BPH tissue samples. HPV-DNA was positive in only 1 of the 60 PCa samples (1.7%. The HPV type of this sample was identified as HPV-57. The distribution of the three genotypes, Arg/Arg, Arg/Pro and Pro/Pro was found to be 45.6, 45.6, and 8.8% in the PCa group and 57.1%, 34.3% and 8.6% in the control group, respectively. Compared with the control group, patients with PCa had a higher frequency of the Arg/Pro genotype and Proline allele (odds ratio (OR=1.67, 95% confidence interval (CI=0.68-4.09, p=0.044; OR=1.13, 95% CI=0.76-1.68, p=0.021, respectively. Conclusions The results of the study do not support the hyphothesis that prostate cancer is associated with HPV infection but indicated that Proline allele can be a risk factor in the development of PCa in the Turkish population.

  4. Null cone superspace supergravity

    International Nuclear Information System (INIS)

    Downes-Martin, S.G.

    1980-03-01

    The null cone formalism is used to derive a 2(N-1) parameter family of constraints for O(N) extended superspace supergravity. The invariance groups of these constraints is analysed and is found to be [subgroup U submanifold] contains GL(4,R) for N = 1, the submanifold being eliminated for N > 1. The invariance group defines non-Weyl rotations on the superbein which combine to form Weyl transformations on the supertangent space metric. The invariance of the supergravity Lagrangian under these transformations is discussed. (Auth.)

  5. Visible Nulling Coronagraph Progress Report

    Science.gov (United States)

    Lyon, R. G.; Clampin, M.; Woodruff, R. A.; Vasudevan, G.; Thompson, P.; Petrone, P.; Madison, T.; Rizzo, M.; Melnick, G.; Tolls, V.

    2010-10-01

    We report on recent laboratory results with the NASA Goddard Space Flight Center Visible Nulling Coronagraph (VNC) testbed. We have achieved focal plane contrasts of 108 and approaching 109 at inner working angles of 2 λ/D and 4 λ/D, respectively. Results were obtained with a broadband source and 40 nm filter centered on 630 nm. A null control breadboard (NCB) was also developed to assess and quantify MEMS based deformable mirror technology (DM), and to develop and assess closed-loop null control algorithms. We have demonstrated closed-loop performance at 27 Hz.

  6. Null lifts and projective dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Cariglia, Marco, E-mail: marco@iceb.ufop.br

    2015-11-15

    We describe natural Hamiltonian systems using projective geometry. The null lift procedure endows the tangent bundle with a projective structure where the null Hamiltonian is identified with a projective conic and induces a Weyl geometry. Projective transformations generate a set of known and new dualities between Hamiltonian systems, as for example the phenomenon of coupling-constant metamorphosis. We conclude outlining how this construction can be extended to the quantum case for Eisenhart–Duval lifts.

  7. Bare Quantum Null Energy Condition.

    Science.gov (United States)

    Fu, Zicao; Marolf, Donald

    2018-02-16

    The quantum null energy condition (QNEC) is a conjectured relation between a null version of quantum field theory energy and derivatives of quantum field theory von Neumann entropy. In some cases, divergences cancel between these two terms and the QNEC is intrinsically finite. We study the more general case here where they do not and argue that a QNEC can still hold for bare (unrenormalized) quantities. While the original QNEC applied only to locally stationary null congruences in backgrounds that solve semiclassical theories of quantum gravity, at least in the formal perturbation theory at a small Planck length, the quantum focusing conjecture can be viewed as the special case of our bare QNEC for which the metric is on shell.

  8. Visible nulling coronagraph testbed results

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Thompson, Patrick; Petrone, Peter; Madison, Timothy; Rizzo, Maxime; Melnick, Gary; Tolls, Volker

    2009-08-01

    We report on our recent laboratory results with the NASA/Goddard Space Flight Center (GSFC) Visible Nulling Coronagraph (VNC) testbed. We have experimentally achieved focal plane contrasts of 1 x 108 and approaching 109 at inner working angles of 2 * wavelength/D and 4 * wavelength/D respectively where D is the aperture diameter. The result was obtained using a broadband source with a narrowband spectral filter of width 10 nm centered on 630 nm. To date this is the deepest nulling result with a visible nulling coronagraph yet obtained. Developed also is a Null Control Breadboard (NCB) to assess and quantify MEMS based segmented deformable mirror technology and develop and assess closed-loop null sensing and control algorithm performance from both the pupil and focal planes. We have demonstrated closed-loop control at 27 Hz in the laboratory environment. Efforts are underway to first bring the contrast to > 109 necessary for the direct detection and characterization of jovian (Jupiter-like) and then to > 1010 necessary for terrestrial (Earth-like) exosolar planets. Short term advancements are expected to both broaden the spectral passband from 10 nm to 100 nm and to increase both the long-term stability to > 2 hours and the extent of the null out to a ~ 10 * wavelength / D via the use of MEMS based segmented deformable mirror technology, a coherent fiber bundle, achromatic phase shifters, all in a vacuum chamber at the GSFC VNC facility. Additionally an extreme stability textbook sized compact VNC is under development.

  9. Standard and Null Weak Values

    OpenAIRE

    Zilberberg, Oded; Romito, Alessandro; Gefen, Yuval

    2013-01-01

    Weak value (WV) is a quantum mechanical measurement protocol, proposed by Aharonov, Albert, and Vaidman. It consists of a weak measurement, which is weighed in, conditional on the outcome of a later, strong measurement. Here we define another two-step measurement protocol, null weak value (NVW), and point out its advantages as compared to WV. We present two alternative derivations of NWVs and compare them to the corresponding derivations of WVs.

  10. Bodyweight Assessment of Enamelin Null Mice

    Directory of Open Access Journals (Sweden)

    Albert H.-L. Chan

    2013-01-01

    Full Text Available The Enam null mice appear to be smaller than wild-type mice, which prompted the hypothesis that enamel defects negatively influence nutritional intake and bodyweight gain (BWG. We compared the BWG of Enam−/− and wild-type mice from birth (D0 to Day 42 (D42. Wild-type (WT and Enam−/− (N mice were given either hard chow (HC or soft chow (SC. Four experimental groups were studied: WTHC, WTSC, NHC, and NSC. The mother’s bodyweight (DBW and the average litter bodyweight (ALBW were obtained from D0 to D21. After D21, the pups were separated from the mother and provided the same type of food. Litter bodyweights were measured until D42. ALBW was compared at 7-day intervals using one-way ANOVA, while the influence of DBW on ALBW was analyzed by mixed-model analyses. The ALBW of Enam−/− mice maintained on hard chow (NHC was significantly lower than the two WT groups at D21 and the differences persisted into young adulthood. The ALBW of Enam−/− mice maintained on soft chow (NSC trended lower, but was not significantly different than that of the WT groups. We conclude that genotype, which affects enamel integrity, and food hardness influence bodyweight gain in postnatal and young adult mice.

  11. No association of GSTM1 null polymorphism with endometriosis in women from central and southern Iran

    Directory of Open Access Journals (Sweden)

    Razieh Dehghani Firouzabadi

    2012-01-01

    Full Text Available Background: Endometriosis is one of the most common gynecologic disorders. It is a complex trait and both genetic and environmental factors have been implicated in its pathogenesis. There is growing evidence indicating that exposure to environmental contaminants is a risk factor for endometriosis. Glutathione-S-Transferase M1 (GSTM1 is one of the genes involved in detoxification of endogenous and exogenous compounds. Objective: Several studies have indicated an association between GSTM1 null mutation and endometriosis. In this study, the possible association between the GSTM1 gene null genotype and susceptibility to endometriosis in woman from central and southern Iran was investigated.Materials and Methods: One hundred and one unrelated premenopausal women with endometriosis and 142 unrelated healthy premenopausal women without endometriosis were enrolled in the study. Genomic DNA was extracted from Peripheral blood in all subjects. GSTM1 null genotyping was performed by polymerase chain reaction (PCR.Results: There was no significant difference between frequencies of GSTM1 null genotype in case and control groups (50.5% Vs. 52.1%, p=0.804. Furthermore, this genotype was not associated with severity of endometriosis in our sample (p=0.77. Conclusion: further studies involving gene-environment and gene-gene interactions, particularly combination of GSTM1 and other GST gene family polymorphisms are needed.

  12. The Importance of Proving the Null

    Science.gov (United States)

    Gallistel, C. R.

    2009-01-01

    Null hypotheses are simple, precise, and theoretically important. Conventional statistical analysis cannot support them; Bayesian analysis can. The challenge in a Bayesian analysis is to formulate a suitably vague alternative, because the vaguer the alternative is (the more it spreads out the unit mass of prior probability), the more the null is…

  13. Infectious genotype 1a, 1b, 2a, 2b, 3a, 5a, 6a and 7a hepatitis C virus lacking the hypervariable region 1 (HVR1)

    DEFF Research Database (Denmark)

    2014-01-01

    .sub.1389c,A1590G (6a/2a) constructs for the deletion of Hypervariable Region 1 (HVR1) to construct viable, JFH 1 (genotype 2a) based, genomes. The present inventors serially passaged the viruses in cell culture obtaining relatively high HCV RNA titers and infectivity titers. Sequence analysis...... of the viruses identified mutations adapting H77/JFH 1.sub.T27OOC,A4O8OT,.DELTA.HVR1 (1a/2a), J8/JFH .sub.1.DELTA.HVR1 (2b/2a), S52/JFH 1.sub.T2718G,T716OC,.DELTA.HVR1 (3a/2a) and J4/JFH 1.sub.T2996C,A4827T,.DELTA.HVR1 (1b/2a) to the HVR1 deletion....

  14. Precision engineering for PRRSV resistance in pigs: Macrophages from genome edited pigs lacking CD163 SRCR5 domain are fully resistant to both PRRSV genotypes while maintaining biological function.

    Directory of Open Access Journals (Sweden)

    Christine Burkard

    2017-02-01

    Full Text Available Porcine Reproductive and Respiratory Syndrome (PRRS is a panzootic infectious disease of pigs, causing major economic losses to the world-wide pig industry. PRRS manifests differently in pigs of all ages but primarily causes late-term abortions and stillbirths in sows and respiratory disease in piglets. The causative agent of the disease is the positive-strand RNA PRRS virus (PRRSV. PRRSV has a narrow host cell tropism, limited to cells of the monocyte/macrophage lineage. CD163 has been described as a fusion receptor for PRRSV, whereby the scavenger receptor cysteine-rich domain 5 (SRCR5 region was shown to be an interaction site for the virus in vitro. CD163 is expressed at high levels on the surface of macrophages, particularly in the respiratory system. Here we describe the application of CRISPR/Cas9 to pig zygotes, resulting in the generation of pigs with a deletion of Exon 7 of the CD163 gene, encoding SRCR5. Deletion of SRCR5 showed no adverse effects in pigs maintained under standard husbandry conditions with normal growth rates and complete blood counts observed. Pulmonary alveolar macrophages (PAMs and peripheral blood monocytes (PBMCs were isolated from the animals and assessed in vitro. Both PAMs and macrophages obtained from PBMCs by CSF1 stimulation (PMMs show the characteristic differentiation and cell surface marker expression of macrophages of the respective origin. Expression and correct folding of the SRCR5 deletion CD163 on the surface of macrophages and biological activity of the protein as hemoglobin-haptoglobin scavenger was confirmed. Challenge of both PAMs and PMMs with PRRSV genotype 1, subtypes 1, 2, and 3 and PMMs with PRRSV genotype 2 showed complete resistance to viral infections assessed by replication. Confocal microscopy revealed the absence of replication structures in the SRCR5 CD163 deletion macrophages, indicating an inhibition of infection prior to gene expression, i.e. at entry/fusion or unpacking stages.

  15. Conformal symmetry inheritance in null fluid spacetimes

    International Nuclear Information System (INIS)

    Tupper, B O J; Keane, A J; Hall, G S; Coley, A A; Carot, J

    2003-01-01

    We define inheriting conformal Killing vectors for null fluid spacetimes and find the maximum dimension of the associated inheriting Lie algebra. We show that for non-conformally flat null fluid spacetimes, the maximum dimension of the inheriting algebra is seven and for conformally flat null fluid spacetimes the maximum dimension is eight. In addition, it is shown that there are two distinct classes of non-conformally flat generalized plane wave spacetimes which possess the maximum dimension, and one class in the conformally flat case

  16. Null solution of the Yang-Mills equations

    International Nuclear Information System (INIS)

    Tafel, J.

    1986-05-01

    We investigate the correspondence between null solutions of the Yang-Mills equations and shearfree geodesic null congruences. We give an example of a non-Abelian null solution with twisting rays. (orig.)

  17. Measurement of high-departure aspheres using subaperture stitching with the Variable Optical Null (VON)

    Science.gov (United States)

    Kulawiec, Andrew; Murphy, Paul; DeMarco, Michael

    2010-10-01

    Aspheric surfaces are proven to provide significant benefits to a wide variety of optical systems, but the ability to produce high-precision aspheric surfaces has historically been limited by the ability (or lack thereof) to measure them. Traditionally, aspheric measurements have required dedicated null optics, but the cost, lead time, and calibration difficulty of using null optics has made the use of aspheres more challenging and less attractive. In the past three years, QED has developed the Subaperture Stitching Interferometer for Aspheres (SSI-A®) to help address this limitation, providing flexible aspheric measurement capability of up to 200 waves of aspheric departure from best-fit sphere. Some aspheres, however, have thousands of waves of departure. We have recently developed Variable Optical Null (VON) technology that can null much of the aspheric departure in a subaperture. The VON is automatically configurable and is adjusted to nearly null each specific subaperture of an asphere. This ability to nearly null a local subaperture of an asphere provides a significant boost in aspheric measurement capability, enabling aspheres with up to 1000 waves of departure to be measured, without the use of dedicated null optics. We outline the basic principles of subaperture stitching and VON technology, demonstrate the extended capability provided by the VON, and present measurement results from the new Aspheric Stitching Interferometer (ASI®).

  18. Null-strut calculus. II. Dynamics

    International Nuclear Information System (INIS)

    Kheyfets, A.; LaFave, N.J.; Miller, W.A.

    1990-01-01

    In this paper, we continue from the preceding paper to develop a fully functional Regge calculus geometrodynamic algorithm from the null-strut-calculus construction. The developments discussed include (a) the identification of the Regge calculus analogue of the constraint and evolution equations on the null-strut lattice, (b) a description of the Minkowski solid geometry for the simplicial blocks of the null-strut lattice, (c) a description of the evolution algorithm for the geometrodynamic scheme and an analysis of its consistency, and (d) a presentation of the dynamical degrees of freedom for a simplicial hypersurface and the description of an initial-value prescription. To demonstrate qualitatively this new approach to geometrodynamics, we present the most simple application of null-strut calculus that we know of---the Friedmann cosmology using the three-boundary of a 600-cell simplicial polytope to model the simplicial hypersurface

  19. Null structure groups in eleven dimensions

    International Nuclear Information System (INIS)

    Cariglia, Marco; Mac Conamhna, Oisin A. P.

    2006-01-01

    We classify all the structure groups which arise as subgroups of the isotropy group (Spin(7)xR 8 )xR, of a single null Killing spinor in 11 dimensions. We construct the spaces of spinors fixed by these groups. We determine the conditions under which structure subgroups of the maximal null structure group (Spin(7)xR 8 )xR may also be embedded in SU(5), and hence the conditions under which a supersymmetric spacetime admits only null, or both timelike and null, Killing spinors. We discuss how this purely algebraic material will facilitate the direct analysis of the Killing spinor equation of 11 dimensional supergravity, and the classification of supersymmetric spacetimes therein

  20. On smoothness-asymmetric null infinities

    International Nuclear Information System (INIS)

    Valiente Kroon, Juan Antonio

    2006-01-01

    We discuss the existence of asymptotically Euclidean initial data sets for the vacuum Einstein field equations which would give rise (modulo an existence result for the evolution equations near spatial infinity) to developments with a past and a future null infinity of different smoothness. For simplicity, the analysis is restricted to the class of conformally flat, axially symmetric initial data sets. It is shown how the free parameters in the second fundamental form of the data can be used to satisfy certain obstructions to the smoothness of null infinity. The resulting initial data sets could be interpreted as those of some sort of (nonlinearly) distorted Schwarzschild black hole. Their developments would be that they admit a peeling future null infinity, but at the same time have a polyhomogeneous (non-peeling) past null infinity

  1. High-contrast Nulling Interferometry Techniques Project

    Data.gov (United States)

    National Aeronautics and Space Administration — "We are developing rotating-baseline nulling-interferometry techniques and algorithms on the single-aperture Hale and Keck telescopes at near-infrared wavelengths,...

  2. Null-plane quantization of fermions

    International Nuclear Information System (INIS)

    Mustaki, D.

    1990-01-01

    Massive Dirac fermions are canonically quantized on the null plane using the Dirac-Bergmann algorithm. The procedure is carried out in the framework of quantum electrodynamics as an illustration of a rigorous treatment of interacting fermion fields

  3. Identification of several gy4 nulls from the USDA soybean germplasm collection provides new genetic resources for the development of high-quality tofu cultivars.

    Science.gov (United States)

    Kim, Won-Seok; Ho, Heo Jae; Nelson, Randall L; Krishnan, Hari B

    2008-12-10

    Tofu, a cheese-like food made by curdling soy milk, is a major dietary staple of Asian countries. Consumption of tofu and other soy products is steadily increasing in North America due to its well-known health benefits. Soybean A(5), A(4), and B(3) peptide null lines 'Enrei' and 'Raiden' are commonly utilized in breeding programs to develop high-quality tofu cultivars. To expand the genetic diversity it is desirable to identify and utilize other A(5), A(4), and B(3) null genotypes in the development of improved tofu cultivars that are adapted to North American conditions. In this study were screened diverse soybean accessions from the USDA Soybean Germplasm Collection to identify Gy4 mutants, the locus that controls A(5), A(4), and B(3) peptide production. Analysis of total seed proteins from 485 soybean lines by SDS-PAGE enabled the identification of 38 accessions that lacked the A(5), A(4), and B(3) peptides. These accessions showed marked differences in seed size and seed coat color and represented different maturity groups ranging from 0 to IX. To ascertain the molecular basis for the lack of A(5), A(4), and B(3) peptides in the newly identified Gy4 mutants, the nucleotide sequence of a portion of the Gy4 gene was determined from eight soybean accessions representing different maturity groups. These eight Gy4 mutants revealed a single point mutation that changed the translation initiation codon ATG to ATA, resulting in the A(5), A(4), and B(3) null phenotype. The newly identified Gy4 mutants from this study will enable plant breeders to expand the genetic diversity of North American food-quality soybeans and also aid in the development of hypoallergenic soybeans.

  4. On the Penrose inequality along null hypersurfaces

    International Nuclear Information System (INIS)

    Mars, Marc; Soria, Alberto

    2016-01-01

    The null Penrose inequality, i.e. the Penrose inequality in terms of the Bondi energy, is studied by introducing a functional on surfaces and studying its properties along a null hypersurface Ω extending to past null infinity. We prove a general Penrose-type inequality which involves the limit at infinity of the Hawking energy along a specific class of geodesic foliations called Geodesic Asymptotically Bondi (GAB), which are shown to always exist. Whenever this foliation approaches large spheres, this inequality becomes the null Penrose inequality and we recover the results of Ludvigsen–Vickers (1983 J. Phys. A: Math. Gen. 16 3349–53) and Bergqvist (1997 Class. Quantum Grav. 14 2577–83). By exploiting further properties of the functional along general geodesic foliations, we introduce an approach to the null Penrose inequality called the Renormalized Area Method and find a set of two conditions which imply the validity of the null Penrose inequality. One of the conditions involves a limit at infinity and the other a restriction on the spacetime curvature along the flow. We investigate their range of applicability in two particular but interesting cases, namely the shear-free and vacuum case, where the null Penrose inequality is known to hold from the results by Sauter (2008 PhD Thesis Zürich ETH ), and the case of null shells propagating in the Minkowski spacetime. Finally, a general inequality bounding the area of the quasi-local black hole in terms of an asymptotic quantity intrinsic of Ω is derived. (paper)

  5. Latex allergy and filaggrin null mutations

    DEFF Research Database (Denmark)

    Carlsen, Berit C; Meldgaard, Michael; Hamann, Dathan

    2011-01-01

    to aeroallergens and it is possible that filaggrin null mutations also increase the risk of latex allergy. The aim of this paper was to examine the association between filaggrin null mutations and type I latex allergy. Methods Twenty latex allergic and 24 non-latex allergic dentists and dental assistants...... in the cases in this study may not have occurred through direct skin contact but through the respiratory organs via latex proteins that are absorbed in glove powder and aerosolized...

  6. OBSERVATION OF MAGNETIC RECONNECTION AT A 3D NULL POINT ASSOCIATED WITH A SOLAR ERUPTION

    International Nuclear Information System (INIS)

    Sun, J. Q.; Yang, K.; Cheng, X.; Ding, M. D.; Zhang, J.

    2016-01-01

    Magnetic null has long been recognized as a special structure serving as a preferential site for magnetic reconnection (MR). However, the direct observational study of MR at null-points is largely lacking. Here, we show the observations of MR around a magnetic null associated with an eruption that resulted in an M1.7 flare and a coronal mass ejection. The Geostationary Operational Environmental Satellites X-ray profile of the flare exhibited two peaks at ∼02:23 UT and ∼02:40 UT on 2012 November 8, respectively. Based on the imaging observations, we find that the first and also primary X-ray peak was originated from MR in the current sheet (CS) underneath the erupting magnetic flux rope (MFR). On the other hand, the second and also weaker X-ray peak was caused by MR around a null point located above the pre-eruption MFR. The interaction of the null point and the erupting MFR can be described as a two-step process. During the first step, the erupting and fast expanding MFR passed through the null point, resulting in a significant displacement of the magnetic field surrounding the null. During the second step, the displaced magnetic field started to move back, resulting in a converging inflow and subsequently the MR around the null. The null-point reconnection is a different process from the current sheet reconnection in this flare; the latter is the cause of the main peak of the flare, while the former is the cause of the secondary peak of the flare and the conspicuous high-lying cusp structure.

  7. Null alleles and sequence variations at primer binding sites of STR loci within multiplex typing systems.

    Science.gov (United States)

    Yao, Yining; Yang, Qinrui; Shao, Chengchen; Liu, Baonian; Zhou, Yuxiang; Xu, Hongmei; Zhou, Yueqin; Tang, Qiqun; Xie, Jianhui

    2018-01-01

    Rare variants are widely observed in human genome and sequence variations at primer binding sites might impair the process of PCR amplification resulting in dropouts of alleles, named as null alleles. In this study, 5 cases from routine paternity testing using PowerPlex ® 21 System for STR genotyping were considered to harbor null alleles at TH01, FGA, D5S818, D8S1179, and D16S539, respectively. The dropout of alleles was confirmed by using alternative commercial kits AGCU Expressmarker 22 PCR amplification kit and AmpFℓSTR ® . Identifiler ® Plus Kit, and sequencing results revealed a single base variation at the primer binding site of each STR locus. Results from the collection of previous reports show that null alleles at D5S818 were frequently observed in population detected by two PowerPlex ® typing systems and null alleles at D19S433 were mostly observed in Japanese population detected by two AmpFℓSTR™ typing systems. Furthermore, the most popular mutation type appeared the transition from C to T with G to A, which might have a potential relationship with DNA methylation. Altogether, these results can provide helpful information in forensic practice to the elimination of genotyping discrepancy and the development of primer sets. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Entrainment to feeding but not to light: circadian phenotype of VPAC2 receptor-null mice.

    Science.gov (United States)

    Sheward, W John; Maywood, Elizabeth S; French, Karen L; Horn, Jacqueline M; Hastings, Michael H; Seckl, Jonathan R; Holmes, Megan C; Harmar, Anthony J

    2007-04-18

    The master clock driving mammalian circadian rhythms is located in the suprachiasmatic nuclei (SCN) of the hypothalamus and entrained by daily light/dark cycles. SCN lesions abolish circadian rhythms of behavior and result in a loss of synchronized circadian rhythms of clock gene expression in peripheral organs (e.g., the liver) and of hormone secretion (e.g., corticosterone). We examined rhythms of behavior, hepatic clock gene expression, and corticosterone secretion in VPAC2 receptor-null (Vipr2-/-) mice, which lack a functional SCN clock. Unexpectedly, although Vipr2-/- mice lacked robust circadian rhythms of wheel-running activity and corticosterone secretion, hepatic clock gene expression was strongly rhythmic, but advanced in phase compared with that in wild-type mice. The timing of food availability is thought to be an important entrainment signal for circadian clocks outside the SCN. Vipr2-/- mice consumed food significantly earlier in the 24 h cycle than wild-type mice, consistent with the observed timing of peripheral rhythms of circadian gene expression. When restricted to feeding only during the daytime (RF), mice develop rhythms of activity and of corticosterone secretion in anticipation of feeding time, thought to be driven by a food-entrainable circadian oscillator, located outside the SCN. Under RF, mice of both genotypes developed food-anticipatory rhythms of activity and corticosterone secretion, and hepatic gene expression rhythms also became synchronized to the RF stimulus. Thus, food intake is an effective zeitgeber capable of coordinating circadian rhythms of behavior, peripheral clock gene expression, and hormone secretion, even in the absence of a functional SCN clock.

  9. Null Subjects in European and Brazilian Portuguese

    Directory of Open Access Journals (Sweden)

    Pilar Barbosa

    2005-12-01

    Full Text Available The goals of this paper are twofold: a to provide a structural account of the effects of the informal ‘Avoid Pronoun Principle’, proposed in Chomsky (1981: 65 for the Null Subject Languages (NSLs, and b to compare, in European and Brazilian Portuguese (EP and BP, the distribution of the third person pronouns in its full and null forms, to check whether in written corpora BP incorporates signs of the ongoing loss of the null subject, largely attested in its contemporary spoken language. The strong theoretical claim is that in the Romance non-NSLs the pre-verbal subject is sitting in Spec of IP, while in the Romance NSLs it is Clitic Left-Dislocated (or is extracted by A-bar movement if it belongs to a restricted set of non-referential quantified expressions. The paper provides quantitative evidence that BP is losing the properties associated with the Null Subject Parameter. In its qualitative analysis, it shows that the contrasts between EP and BP are easily accounted for if the two derivations are assumed and if the null subjects in the two varieties are considered to be of a different nature: a pronoun in EP and a pronominal anaphor in BP.

  10. Reduced alcohol consumption in mice lacking preprodynorphin.

    Science.gov (United States)

    Blednov, Yuri A; Walker, Danielle; Martinez, Marni; Harris, R Adron

    2006-10-01

    Many studies suggest a role for endogenous opioid peptides and their receptors in regulation of ethanol intake. It is commonly accepted that the kappa-opioid receptors and their endogenous ligands, dynorphins, produce a dysphoric state and therefore may be responsible for avoidance of alcohol. We used mutant mice lacking preprodynorphin in a variety of behavioral tests of alcohol actions. Null mutant female, but not male, mice showed significantly lower preference for alcohol and consumed lower amounts of alcohol in a two-bottle choice test as compared with wild-type littermates. In the same test, knockout mice of both sexes showed a strong reduction of preference for saccharin compared to control mice. In contrast, under conditions of limited (4 h) access (light phase of the light/dark cycle), null mutant mice did not show any differences in consumption of saccharin, but they showed significantly reduced intake of sucrose. To determine the possible cause for reduction of ethanol preference and intake, we studied other ethanol-related behaviors in mice lacking the preprodynorphin gene. There were no differences between null mutant and wild-type mice in ethanol-induced loss of righting reflex, acute ethanol withdrawal, ethanol-induced conditioned place preference, or conditioned taste aversion to ethanol. These results indicate that deletion of preprodynorphin leads to substantial reduction of alcohol intake in female mice, and suggest that this is caused by decreased orosensory reward of alcohol (sweet taste and/or palatability).

  11. Supersymmetric null-like holographic cosmologies

    International Nuclear Information System (INIS)

    Lin Fengli; Wen Wenyu

    2006-01-01

    We construct a new class of 1/4-BPS time dependent domain-wall solutions with null-like metric and dilaton in type II supergravities, which admit a null-like big bang singularity. Based on the domain-wall/QFT correspondence, these solutions are dual to 1/4-supersymmetric quantum field theories living on a boundary cosmological background with time dependent coupling constant and UV cutoff. In particular we evaluate the holographic c function for the 2-dimensional dual field theory living on the corresponding null-like cosmology. We find that this c function runs in accordance with the c-theorem as the boundary universe evolves, this means that the number of degrees of freedom is divergent at big bang and suggests the possible resolution of big bang singularity

  12. Null-strut calculus. I. Kinematics

    International Nuclear Information System (INIS)

    Kheyfets, A.; LaFave, N.J.; Miller, W.A.

    1990-01-01

    This paper describes the kinematics of null-strut calculus---a 3+1 Regge calculus approach to general relativity. We show how to model the geometry of spacetime with simplicial spacelike three-geometries (TET's) linked to ''earlier'' and ''later'' momentumlike lattice surfaces (TET * ) entirely by light rays or ''null struts.'' These three-layered lattice spacetime geometries are defined and analyzed using combinatorial formulas for the structure of polytopes. The following paper in this series describes how these three-layered spacetime lattices are used to model spacetimes in full conformity with Einstein's theory of gravity

  13. A possible association between a dysfunctional skin barrier (filaggrin null-mutation status) and diabetes: a cross-sectional study

    DEFF Research Database (Denmark)

    Thyssen, Jacob P; Linneberg, Allan; Carlsen, Berit C

    2011-01-01

    2 diabetes (p=0.073). Adjustment for age and gender resulted in significant associations for patients with type 2 diabetes (p=0.048) and subjects with self-reported diabetes (p=0.032). Conclusions Adult Danes with a filaggrin null genotype had a significantly increased prevalence of self...... populations of patients with type 1 (n=104) or 2 (n=774) diabetes were genotyped. Results In a crude data analysis, a positive association was detected between the filaggrin null genotype and, respectively, subjects from the general population who reported diabetes (p=0.04) and patients with established type......-reported diabetes. This finding was replicated when an independent sample of Danish patients with established type 2 diabetes was compared with control subjects from the general population....

  14. A Model of Oxidative Stress Management: Moderation of Carbohydrate Metabolizing Enzymes in SOD1-Null Drosophila melanogaster

    Science.gov (United States)

    Bernard, Kristine E.; Parkes, Tony L.; Merritt, Thomas J. S.

    2011-01-01

    The response to oxidative stress involves numerous genes and mutations in these genes often manifest in pleiotropic ways that presumably reflect perturbations in ROS-mediated physiology. The Drosophila melanogaster SOD1-null allele (cSODn108) is proposed to result in oxidative stress by preventing superoxide breakdown. In SOD1-null flies, oxidative stress management is thought to be reliant on the glutathione-dependent antioxidants that utilize NADPH to cycle between reduced and oxidized form. Previous studies suggest that SOD1-null Drosophila rely on lipid catabolism for energy rather than carbohydrate metabolism. We tested these connections by comparing the activity of carbohydrate metabolizing enzymes, lipid and triglyceride concentration, and steady state NADPH:NADP+ in SOD1-null and control transgenic rescue flies. We find a negative shift in the activity of carbohydrate metabolizing enzymes in SOD1-nulls and the NADP+-reducing enzymes were found to have significantly lower activity than the other enzymes assayed. Little evidence for the catabolism of lipids as preferential energy source was found, as the concentration of lipids and triglycerides were not significantly lower in SOD1-nulls compared with controls. Using a starvation assay to impact lipids and triglycerides, we found that lipids were indeed depleted in both genotypes when under starvation stress, suggesting that oxidative damage was not preventing the catabolism of lipids in SOD1-null flies. Remarkably, SOD1-nulls were also found to be relatively resistant to starvation. Age profiles of enzyme activity, triglyceride and lipid concentration indicates that the trends observed are consistent over the average lifespan of the SOD1-nulls. Based on our results, we propose a model of physiological response in which organisms under oxidative stress limit the production of ROS through the down-regulation of carbohydrate metabolism in order to moderate the products exiting the electron transport chain. PMID

  15. Fine art of computing nulling interferometer maps

    Science.gov (United States)

    Hénault, F.

    2008-07-01

    Spaceborne nulling interferometers are often characterized by means of their nulling ratio, which is defined as the deepest possible extinction of one target star supposed to harbor an extra-solar system. Herein is shown that another parameter, which is the transmitting efficiency of nearby bright fringes, is also of prime importance. More generally, "nulling maps" formed by the whole destructive and constructive fringe pattern projected on-sky, are found to be very sensitive on the design of some subsystems constituting the interferometer. In particular, we consider Spatial Filtering (SF) and Achromatic Phase Shifter (APS) devices, both required achieving planet detection and characterization. Consequences of the SF choice (pinhole or single-mode optical fiber) and APS properties (with or without induced pupil-flip) are discussed, for both monochromatic and polychromatic cases. Examples of numerical simulations are provided for single Bracewell interferometer, Angel cross and X-array configurations, demonstrating noticeable differences in the aspect of resulting nulling maps. It is concluded that both FS and APS designs exhibit variable capacities for serendipitous planet discovery.

  16. Matter sources for a null big bang

    International Nuclear Information System (INIS)

    Bronnikov, K A; Zaslavskii, O B

    2008-01-01

    We consider the properties of stress-energy tensors compatible with a null big bang, i.e., cosmological evolution starting from a Killing horizon rather than a singularity. For Kantowski-Sachs cosmologies, it is shown that if matter satisfies the null energy condition, then (i) regular cosmological evolution can only start from a Killing horizon, (ii) matter is absent at the horizon and (iii) matter can only appear in the cosmological region due to interaction with vacuum. The latter is understood phenomenologically as a fluid whose stress tensor is insensitive to boosts in a particular direction. We also argue that matter is absent in a static region beyond the horizon. All this generalizes the observations recently obtained for a mixture of dust and a vacuum fluid. If, however, we admit the existence of phantom matter, its certain special kinds (with the parameter w ≤ -3) are consistent with a null big bang without interaction with vacuum (or without vacuum fluid at all). Then in the static region there is matter with w ≥ -1/3. Alternatively, the evolution can begin from a horizon in an infinitely remote past, leading to a scenario combining the features of a null big bang and an emergent universe

  17. Instabilities and the null energy condition

    International Nuclear Information System (INIS)

    Buniy, Roman V.; Hsu, Stephen D.H.

    2006-01-01

    We show that violation of the null energy condition implies instability in a broad class of models, including gauge theories with scalar and fermionic matter as well as any perfect fluid. When applied to the dark energy, our results imply that w=p/ρ is unlikely to be less than -1. than -1

  18. Covariant quantum mechanics on a null plane

    International Nuclear Information System (INIS)

    Leutwyler, H.; Stern, J.

    1977-03-01

    Lorentz invariance implies that the null plane wave functions factorize into a kinematical part describing the motion of the system as a whole and an inner wave function that involves the specific dynamical properties of the system - in complete correspondence with the non-relativistic situation. Covariance is equivalent to an angular condition which admits non-trivial solutions

  19. Null vectors in superconformal quantum field theory

    International Nuclear Information System (INIS)

    Huang Chaoshang

    1993-01-01

    The superspace formulation of the N=1 superconformal field theory and superconformal Ward identities are used to give a precise definition of fusion. Using the fusion procedure, superconformally covariant differential equations are derived and consequently a complete and straightforward algorithm for finding null vectors in Verma modules of the Neveu-Schwarz algebra is given. (orig.)

  20. Spdef null mice lack conjunctival goblet cells and provide a model of dry eye

    NARCIS (Netherlands)

    Marko, C.K.; Menon, B.B.; Chen, G.; Whitsett, J.A.; Clevers, H.; Gipson, I.K.

    2013-01-01

    Goblet cell numbers decrease within the conjunctival epithelium in drying and cicatrizing ocular surface diseases. Factors regulating goblet cell differentiation in conjunctival epithelium are unknown. Recent data indicate that the transcription factor SAM-pointed domain epithelial-specific

  1. Spdef Null Mice Lack Conjunctival Goblet Cells and Provide a Model of Dry Eye

    OpenAIRE

    Marko, Christina K.; Menon, Balaraj B.; Chen, Gang; Whitsett, Jeffrey A.; Clevers, Hans; Gipson, Ilene K.

    2013-01-01

    Goblet cell numbers decrease within the conjunctival epithelium in drying and cicatrizing ocular surface diseases. Factors regulating goblet cell differentiation in conjunctival epithelium are unknown. Recent data indicate that the transcription factor SAM-pointed domain epithelial-specific transcription factor (Spdef) is essential for goblet cell differentiation in tracheobronchial and gastrointestinal epithelium of mice. Using Spdef−/− mice, we determined that Spdef is required for conjunct...

  2. GST M1-T1 null allele frequency patterns in geographically assorted human populations: a phylogenetic approach.

    Directory of Open Access Journals (Sweden)

    Senthilkumar Pitchalu Kasthurinaidu

    Full Text Available Genetic diversity in drug metabolism and disposition is mainly considered as the outcome of the inter-individual genetic variation in polymorphism of drug-xenobiotic metabolizing enzyme (XME. Among the XMEs, glutathione-S-transferases (GST gene loci are an important candidate for the investigation of diversity in allele frequency, as the deletion mutations in GST M1 and T1 genotypes are associated with various cancers and genetic disorders of all major Population Affiliations (PAs. Therefore, the present population based phylogenetic study was focused to uncover the frequency distribution pattern in GST M1 and T1 null genotypes among 45 Geographically Assorted Human Populations (GAHPs. The frequency distribution pattern for GST M1 and T1 null alleles have been detected in this study using the data derived from literatures representing 44 populations affiliated to Africa, Asia, Europe, South America and the genome of PA from Gujarat, a region in western India. Allele frequency counting for Gujarat PA and scattered plot analysis for geographical distribution among the PAs were performed in SPSS-21. The GST M1 and GST T1 null allele frequencies patterns of the PAs were computed in Seqboot, Gendist program of Phylip software package (3.69 versions and Unweighted Pair Group method with Arithmetic Mean in Mega-6 software. Allele frequencies from South African Xhosa tribe, East African Zimbabwe, East African Ethiopia, North African Egypt, Caucasian, South Asian Afghanistan and South Indian Andhra Pradesh have been identified as the probable seven patterns among the 45 GAHPs investigated in this study for GST M1-T1 null genotypes. The patternized null allele frequencies demonstrated in this study for the first time addresses the missing link in GST M1-T1 null allele frequencies among GAHPs.

  3. Gravitational collapse of a cylindrical null shell in vacuum

    Directory of Open Access Journals (Sweden)

    S. Khakshournia

    2008-03-01

    Full Text Available   Barrabès-Israel null shell formalism is used to study the gravitational collapse of a thin cylindrical null shell in vacuum. In general the lightlike matter shell whose history coincides with a null hypersurface is characterized by a surface energy density. In addition, a gravitational impulsive wave is present on this null hypersurface whose generators admit both the shear and expansion. In the case of imposing the cylindrical flatness the surface energy-momentum tensor of the matter shell on the null hypersurface vanishes and the null hyper- surface is just the history of the gravitational wave .

  4. Desmanthus GENOTYPES

    Directory of Open Access Journals (Sweden)

    JOSÉ HENRIQUE DE ALBUQUERQUE RANGEL

    2015-01-01

    Full Text Available Desmanthus is a genus of forage legumes with potential to improve pastures and livestock produc-tion on clay soils of dry tropical and subtropical regions such as the existing in Brazil and Australia. Despite this patterns of natural or enforced after-ripening of Desmanthus seeds have not been well established. Four year old seed banks of nine Desmanthus genotypes at James Cook University were accessed for their patterns of seed softe-ning in response to a range of temperatures. Persistent seed banks were found to exist under all of the studied ge-notypes. The largest seeds banks were found in the genotypes CPI 78373 and CPI 78382 and the smallest in the genotypes CPI’s 37143, 67643, and 83563. An increase in the percentage of softened seeds was correlated with higher temperatures, in two patterns of response: in some accessions seeds were not significantly affected by tempe-ratures below 80º C; and in others, seeds become soft when temperature rose to as little as 60 ºC. At 80 °C the heat started to depress germination. High seed production of Desmanthus associated with dependence of seeds on eleva-ted temperatures to softening can be a very important strategy for plants to survive in dry tropical regions.

  5. Apoptosis in spermatogonia irradiated P53 null mice

    International Nuclear Information System (INIS)

    Streit-Bianchi, M.; Hendry, J.H.; Roberts, S.A.; Morris, J.D.; Durgaryan, A.A.

    2007-01-01

    Complete text of publication follows. The exposure of germ cells to ionizing radiations is of concern both from high-dose therapeutic exposures and from low doses causing deleterious trans-generational mutations. P53 protein plays an important role in cellular damage and is expressed in the testis normally during meiosis, its expression being localised to the preleptotene and early/mid pachytene spermatocytes. P53 null mice, heterozygotes possessing a 129 Sv/C57BL6 genetic background and B6D2F1 mice have been irradiated to 1 and 2 Gy single doses. Fractionated exposures of 1+1 Gy at 4 hours interval were also carried out. Apoptosis induction, spermatogonia and spermatocytes survival were assessed by microscope analysis of histological samples at 4 to 96 hours after irradiation in time-course experiments. The same end-points were also assessed at 72 and 96 hours after irradiation to single doses in the region between 20cGy to 2Gy. A dose dependent level of p53 expression was observed at 4 hours after irradiation to 1 and 2 Gy which returned to normal level by 24 hours. Our data support a two process mode of apoptosis with a first wave around 12 hours followed by a second wave at 2-3 days. The first wave apoptosis is substantially reduced in p53 null mice whereas the second wave is reduced in B6D2F1 mice. The initial increase in apoptosis was delayed in some stages of the of germ cells development which were identified by the spermatids shape. Clear correlation exists between apoptosis and survival assessed in stage XI-XII Tubules 72 hours after irradiation. The data are in agreement with other data in literature indicating that irradiated spermatogonia die through apoptosis. The lack of apoptosis observed in p53 null mice results in a very high survival rate of daughter cells assessed later. Theses spermatocytes and the following progenitor cells are likely to carry mutations as most will not die in the smaller second wave of apoptosis observed 3 days after

  6. Nulling tomography with weak gravitational lensing

    International Nuclear Information System (INIS)

    Huterer, Dragan; White, Martin

    2005-01-01

    We explore several strategies of eliminating (or nulling) the small-scale information in weak lensing convergence power spectrum measurements in order to protect against undesirable effects, for example, the effects of baryonic cooling and pressure forces on the distribution of large-scale structures. We selectively throw out the small-scale information in the convergence power spectrum that is most sensitive to the unwanted bias, while trying to retain most of the sensitivity to cosmological parameters. The strategies are effective in the difficult but realistic situations when we are able to guess the form of the contaminating effect only approximately. However, we also find that the simplest scheme of simply not using information from the largest multipoles works about as well as the proposed techniques in most, although not all, realistic cases. We advocate further exploration of nulling techniques and believe that they will find important applications in the weak lensing data mining

  7. Collapse and bounce of null fluids

    OpenAIRE

    Creelman, Bradley; Booth, Ivan

    2016-01-01

    Exact solutions describing the spherical collapse of null fluids can contain regions which violate the energy conditions. Physically the violations occur when the infalling matter continues to move inwards even when non-gravitational repulsive forces become stronger than gravity. In 1991 Ori proposed a resolution for these violations: spacetime surgery should be used to replace the energy condition violating region with an outgoing solution. The matter bounces. We revisit and implement this p...

  8. Null balance type electrostatic generating voltmeters

    International Nuclear Information System (INIS)

    Mahant, A.K.; Sidhu, N.P.S.; Gupta, U.C.

    1977-01-01

    A description is given of a null balance type generating voltmeter for measuring high D.C. voltage upto about 400 kV. The paper discusses the principle of operation, design, calibration and performance of the instrument. Main advantages of the device are: (1) it does not load the high voltage source, (2) no physical connection is required with the H.T. terminal and (3) calibration is independent of the rotor's frequency and amplifier's gain. (author)

  9. Null controllability of the viscous Camassa–Holm equation with ...

    Indian Academy of Sciences (India)

    In this paper, we study the null controllability of the viscous Camassa–. Holm equation on the one-dimensional torus. By using a moving distributed control, we obtain that the system is null controllable for a given data with certain regularity. Keywords. Viscous Camassa–Holm equation; null controllability; moving control;.

  10. Clausius entropy for arbitrary bifurcate null surfaces

    International Nuclear Information System (INIS)

    Baccetti, Valentina; Visser, Matt

    2014-01-01

    Jacobson’s thermodynamic derivation of the Einstein equations was originally applied only to local Rindler horizons. But at least some parts of that construction can usefully be extended to give meaningful results for arbitrary bifurcate null surfaces. As presaged in Jacobson’s original article, this more general construction sharply brings into focus the questions: is entropy objectively ‘real’? Or is entropy in some sense subjective and observer-dependent? These innocent questions open a Pandora’s box of often inconclusive debate. A consensus opinion, though certainly not universally held, seems to be that Clausius entropy (thermodynamic entropy, defined via a Clausius relation dS=đQ/T) should be objectively real, but that the ontological status of statistical entropy (Shannon or von Neumann entropy) is much more ambiguous, and much more likely to be observer-dependent. This question is particularly pressing when it comes to understanding Bekenstein entropy (black hole entropy). To perhaps further add to the confusion, we shall argue that even the Clausius entropy can often be observer-dependent. In the current article we shall conclusively demonstrate that one can meaningfully assign a notion of Clausius entropy to arbitrary bifurcate null surfaces—effectively defining a ‘virtual Clausius entropy’ for arbitrary ‘virtual (local) causal horizons’. As an application, we see that we can implement a version of the generalized second law (GSL) for this virtual Clausius entropy. This version of GSL can be related to certain (nonstandard) integral variants of the null energy condition. Because the concepts involved are rather subtle, we take some effort in being careful and explicit in developing our framework. In future work we will apply this construction to generalize Jacobson’s derivation of the Einstein equations. (paper)

  11. Generalized frame of reference with null congruence

    International Nuclear Information System (INIS)

    Ferrarese, G.; Antonelli, R.

    2000-01-01

    The paper derives the main properties of a generalized frame of reference with a null congruence (light flux), by means of adapted non-holonomic techniques; then it studies the geometry of the space-time in terms of non-orthogonal projection: longitudinal and transverse covariant derivatives and corresponding commutation formulae, decomposition of the Riemann and gravitational tensors, lie derivatives of the Ricci rotation coefficients, transverse Bianchi identity. Application to the (absolute and relative) light flux: kinematical characteristics and screen, Sachs theorems etc. are also given

  12. Dall-Null tester for spaceborne applications

    Science.gov (United States)

    Wingler, R. L.

    1984-12-01

    This is a study to design a self correcting primary mirror system for a space telescope. The design is centered around a Dall-Null tester (a Foucault knife-edge tester with compensating lens). An indepth study of the theory of the Foucault test from Foucault's original publications to current work is presented. Also short comings of the diffraction approach are shown. The findings of a simple experiment showed the way to the correct explanation as to the workings of the test. Based on this new explanation, a computer program to find the error in the surface of the mirror from the irradiance pattern provided by the Dall-Null tester was developed. The computer program with a sample run is included in the appendixes A and B. The basic design of an adaptive optic system for a spaceborne application is also presented in the paper. This design has the desired quality of being able to correct the mirror while the telescope is in use. The equations being independent of wavelength allows for the design to be applied to systems working outside of the visible spectrum as well as the systems working in the visible.

  13. Averaged null energy condition from causality

    Science.gov (United States)

    Hartman, Thomas; Kundu, Sandipan; Tajdini, Amirhossein

    2017-07-01

    Unitary, Lorentz-invariant quantum field theories in flat spacetime obey mi-crocausality: commutators vanish at spacelike separation. For interacting theories in more than two dimensions, we show that this implies that the averaged null energy, ∫ duT uu , must be non-negative. This non-local operator appears in the operator product expansion of local operators in the lightcone limit, and therefore contributes to n-point functions. We derive a sum rule that isolates this contribution and is manifestly positive. The argument also applies to certain higher spin operators other than the stress tensor, generating an infinite family of new constraints of the form ∫ duX uuu··· u ≥ 0. These lead to new inequalities for the coupling constants of spinning operators in conformal field theory, which include as special cases (but are generally stronger than) the existing constraints from the lightcone bootstrap, deep inelastic scattering, conformal collider methods, and relative entropy. We also comment on the relation to the recent derivation of the averaged null energy condition from relative entropy, and suggest a more general connection between causality and information-theoretic inequalities in QFT.

  14. Recent developments with the visible nulling coronagraph

    Science.gov (United States)

    Hicks, Brian A.; Lyon, Richard G.; Bolcar, Matthew R.; Clampin, Mark; Petrone, Peter; Helmbrecht, Michael A.; Howard, Joseph M.; Miller, Ian J.

    2016-08-01

    A wide array of general astrophysics studies including detecting and characterizing habitable exoplanets could be enabled by a future large segmented telescope with sensitivity in the UV, optical, and infrared bands. When paired with a starshade or coronagraph, such an observatory could enable direct imaging and detailed spectroscopic observations of nearby Earth-like habitable zone planets. Over the past several years, a laboratory-based Visible Nulling Coronagraph (VNC) has evolved to reach requisite contrasts over a 1 nm bandwidth at narrow source angle separation using a segmented deformable mirror in one arm of a Mach-Zehnder layout. More recent efforts targeted broadband performance following the addition of two sets of half-wave Fresnel rhomb achromatic phase shifters (APS) with the goal of reaching 10-9 contrast, at a separation of 2λ/D, using a 40 nm (6%) bandwidth single mode fiber source. Here we present updates on the VNC broadband nulling effort, including approaches to addressing system contrast limitations.

  15. Singular Null Hypersurfaces in General Relativity

    International Nuclear Information System (INIS)

    Dray, T

    2006-01-01

    Null hypersurfaces are a mathematical consequence of the Lorentzian signature of general relativity; singularities in mathematical models usually indicate where the interesting physics takes place. This book discusses what happens when you combine these ideas. Right from the preface, this is a no-nonsense book. There are two principal approaches to singular shells, one distributional and the other 'cut and paste'; both are treated in detail. A working knowledge of GR is assumed, including familiarity with null tetrads, differential forms, and 3 + 1 decompositions. Despite my own reasonably extensive, closely related knowledge, there was material unfamiliar to me already in chapter 3, although I was reunited with some old friends in later chapters. The exposition is crisp, with a minimum of transition from chapter to chapter. In fact, my main criticism is that there is no clear statement of the organization of the book, nor is there an index. Everything is here, and the story is compelling if you know what to look for, although it is less easy to follow the story if you are not already familiar with it. But this is really a book for experts, and the authors certainly qualify, having played a significant role in developing and extending the results they describe. It is also entirely appropriate that the book is dedicated to Werner Israel, who pioneered the thin-shell approach to (non-null) singular surfaces and later championed the use of similar methods for analysing null shells. After an introductory chapter on impulsive signals, the authors show how the Bianchi identities can be used to classify spacetimes with singular null hypersurfaces. This approach, due to the authors, generalizes the framework originally proposed by Penrose. While astrophysical applications are discussed only briefly, the authors point out that detailed physical characteristics of signals from isolated sources can be determined in this manner. In particular, they describe the behaviour of

  16. Molecular bass for a malic enzyme null mutation

    International Nuclear Information System (INIS)

    Brown, M.L.; Wise, L.S.; Rubin, C.S.

    1987-01-01

    Many tissues from normal (wt) mice have cytosolic malic enzyme (ME) activity and express two mRNAs (2 and 3.1 kb) that code for a single ME polypeptide. Mod-1 null (M-n) mice lack cytosolic ME activity, but express 2.5 and 3.6 kb mRNAs that hybridize with wt ME cDNAs. To investigate the basis for the ME deficiency cDNAs corresponding to M-n ME RNA were cloned. A λgt11 library was prepared using M-n liver mRNA as a template. Wt ME cDNA probes hybridized with several recombinant phages and a 2kb insert with an atypical (non-wt) restriction pattern was subcloned in pGEM 1 and sequenced. The M-n ME cDNA contains an internal directly repeated sequence that corresponds to nts 1109-1617 in the coding region of wt ME cDNA. A restriction fragment from M-n ME cDNA that includes the first 204 bp of repeated sequence and 306 bp of contiguous 5' sequence was subcloned into pGEM 1 and used as a template for synthesizing 32 P-labeled anti-sense RNA. After hybridization with M-n liver RNA the 510 nt transcript was resistant to RNA digestion; after hybridization with wt RNA only fragments corresponding to the normally non-contiguous 204 bp and 306 bp segments of the insert were protected. Thus the partial duplication of coding sequence in M-n ME mRNA is confirmed. Analyses of intron-exon organization in the relevant regions of the wt and M-n ME genes will provide further insights into the mechanism underlying the ME null mutation

  17. Internalizing Null Extraterrestrial "Signals": An Astrobiological App for a Technological Society

    OpenAIRE

    Chaisson, Eric J.

    2014-01-01

    One of the beneficial outcomes of searching for life in the Universe is that it grants greater awareness of our own problems here on Earth. Lack of contact with alien beings to date might actually comprise a null "signal" pointing humankind toward a viable future. Astrobiology has surprising practical applications to human society; within the larger cosmological context of cosmic evolution, astrobiology clarifies the energetic essence of complex systems throughout the Universe, including tech...

  18. On the null origin of the ambitwistor string

    Energy Technology Data Exchange (ETDEWEB)

    Casali, Eduardo [Mathematical Institute, University of Oxford,Woodstock Road, Oxford, OX2 6GG (United Kingdom); Tourkine, Piotr [Department of Applied Mathematics and Theoretical Physics,Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2016-11-07

    In this paper we present the null string origin of the ambitwistor string. Classically, the null string is the tensionless limit of string theory, and so too is the ambitwistor string. Both have as constraint algebra the Galilean Conformal Algebra in two dimensions. But something interesting happens in the quantum theory since there is an ambiguity in quantizing the null string. We show that, given a particular choice of quantization scheme and a particular gauge, the null string coincides with the ambitwistor string both classically and quantum mechanically. We also show that the same holds for the spinning versions of the null string and ambitwistor string. With these results we clarify the relationship between the ambitwistor string, the null string, the usual string and the Hohm-Siegel-Zwiebach theory.

  19. The Harm Done to Reproducibility by the Culture of Null Hypothesis Significance Testing.

    Science.gov (United States)

    Lash, Timothy L

    2017-09-15

    In the last few years, stakeholders in the scientific community have raised alarms about a perceived lack of reproducibility of scientific results. In reaction, guidelines for journals have been promulgated and grant applicants have been asked to address the rigor and reproducibility of their proposed projects. Neither solution addresses a primary culprit, which is the culture of null hypothesis significance testing that dominates statistical analysis and inference. In an innovative research enterprise, selection of results for further evaluation based on null hypothesis significance testing is doomed to yield a low proportion of reproducible results and a high proportion of effects that are initially overestimated. In addition, the culture of null hypothesis significance testing discourages quantitative adjustments to account for systematic errors and quantitative incorporation of prior information. These strategies would otherwise improve reproducibility and have not been previously proposed in the widely cited literature on this topic. Without discarding the culture of null hypothesis significance testing and implementing these alternative methods for statistical analysis and inference, all other strategies for improving reproducibility will yield marginal gains at best. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Cell therapy of congenital corneal diseases with umbilical mesenchymal stem cells: lumican null mice.

    Directory of Open Access Journals (Sweden)

    Hongshan Liu

    Full Text Available BACKGROUND: Keratoplasty is the most effective treatment for corneal blindness, but suboptimal medical conditions and lack of qualified medical personnel and donated cornea often prevent the performance of corneal transplantation in developing countries. Our study aims to develop alternative treatment regimens for congenital corneal diseases of genetic mutation. METHODOLOGY/PRINCIPAL FINDINGS: Human mesenchymal stem cells isolated from neonatal umbilical cords were transplanted to treat thin and cloudy corneas of lumican null mice. Transplantation of umbilical mesenchymal stem cells significantly improved corneal transparency and increased stromal thickness of lumican null mice, but human umbilical hematopoietic stem cells failed to do the same. Further studies revealed that collagen lamellae were re-organized in corneal stroma of lumican null mice after mesenchymal stem cell transplantation. Transplanted umbilical mesenchymal stem cells survived in the mouse corneal stroma for more than 3 months with little or no graft rejection. In addition, these cells assumed a keratocyte phenotype, e.g., dendritic morphology, quiescence, expression of keratocyte unique keratan sulfated keratocan and lumican, and CD34. Moreover, umbilical mesenchymal stem cell transplantation improved host keratocyte functions, which was verified by enhanced expression of keratocan and aldehyde dehydrogenase class 3A1 in lumican null mice. CONCLUSIONS/SIGNIFICANCE: Umbilical mesenchymal stem cell transplantation is a promising treatment for congenital corneal diseases involving keratocyte dysfunction. Unlike donated corneas, umbilical mesenchymal stem cells are easily isolated, expanded, stored, and can be quickly recovered from liquid nitrogen when a patient is in urgent need.

  1. Technology Advancement of the Visible Nulling Coronagraph

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Thompson, Patrick; Bolcar, Matt; Madison, Timothy; Woodruff, Robert; Noecker, Charley; Kendrick, Steve

    2010-01-01

    The critical high contrast imaging technology for the Extrasolar Planetary Imaging Coronagraph (EPIC) mission concept is the visible nulling coronagraph (VNC). EPIC would be capable of imaging jovian planets, dust/debris disks, and potentially super-Earths and contribute to answering how bright the debris disks are for candidate stars. The contrast requirement for EPIC is 10(exp 9) contrast at 125 milli-arseconds inner working angle. To advance the VNC technology NASA/Goddard Space Flight Center, in collaboration with Lockheed-Martin, previously developed a vacuum VNC testbed, and achieved narrowband and broadband suppression of the core of the Airy disk. Recently our group was awarded a NASA Technology Development for Exoplanet Missions to achieve two milestones: (i) 10(exp 8) contrast in narrowband light, and, (ii) 10(ecp 9) contrast in broader band light; one milestone per year, and both at 2 Lambda/D inner working angle. These will be achieved with our 2nd generation testbed known as the visible nulling testbed (VNT). It contains a MEMS based hex-packed segmented deformable mirror known as the multiple mirror array (MMA) and coherent fiber bundle, i.e. a spatial filter array (SFA). The MMA is in one interferometric arm and works to set the wavefront differences between the arms to zero. Each of the MMA segments is optically mapped to a single mode fiber of the SFA, and the SFA passively cleans the sub-aperture wavefront error leaving only piston, tip and tilt error to be controlled. The piston degree of freedom on each segment is used to correct the wavefront errors, while the tip/tilt is used to simultaneously correct the amplitude errors. Thus the VNT controls both amplitude and wavefront errors with a single MMA in closed-loop in a vacuum tank at approx.20 Hz. Herein we will discuss our ongoing progress with the VNT.

  2. [Dilemma of null hypothesis in ecological hypothesis's experiment test.

    Science.gov (United States)

    Li, Ji

    2016-06-01

    Experimental test is one of the major test methods of ecological hypothesis, though there are many arguments due to null hypothesis. Quinn and Dunham (1983) analyzed the hypothesis deduction model from Platt (1964) and thus stated that there is no null hypothesis in ecology that can be strictly tested by experiments. Fisher's falsificationism and Neyman-Pearson (N-P)'s non-decisivity inhibit statistical null hypothesis from being strictly tested. Moreover, since the null hypothesis H 0 (α=1, β=0) and alternative hypothesis H 1 '(α'=1, β'=0) in ecological progresses are diffe-rent from classic physics, the ecological null hypothesis can neither be strictly tested experimentally. These dilemmas of null hypothesis could be relieved via the reduction of P value, careful selection of null hypothesis, non-centralization of non-null hypothesis, and two-tailed test. However, the statistical null hypothesis significance testing (NHST) should not to be equivalent to the causality logistical test in ecological hypothesis. Hence, the findings and conclusions about methodological studies and experimental tests based on NHST are not always logically reliable.

  3. Broadband Active Segmented Aperture and Radial Shear Nulling

    Data.gov (United States)

    National Aeronautics and Space Administration — The Visible Nulling Coronagraph (VNC) is a starlight suppression system for enabling exoplanet detectionand atmospheric measurement. Conceptual space telescope...

  4. Alterations in gene expression in mutant amyloid precursor protein transgenic mice lacking Niemann-Pick type C1 protein.

    Directory of Open Access Journals (Sweden)

    Mahua Maulik

    Full Text Available Niemann-Pick type C (NPC disease, a rare autosomal recessive disorder caused mostly by mutation in NPC1 gene, is pathologically characterized by the accumulation of free cholesterol in brain and other tissues. This is accompanied by gliosis and loss of neurons in selected brain regions, including the cerebellum. Recent studies have shown that NPC disease exhibits intriguing parallels with Alzheimer's disease, including the presence of neurofibrillary tangles and increased levels of amyloid precursor protein (APP-derived β-amyloid (Aβ peptides in vulnerable brain neurons. To evaluate the role of Aβ in NPC disease, we determined the gene expression profile in selected brain regions of our recently developed bigenic ANPC mice, generated by crossing APP transgenic (Tg mice with heterozygous Npc1-deficient mice. The ANPC mice exhibited exacerbated neuronal and glial pathology compared to other genotypes [i.e., APP-Tg, double heterozygous (Dhet, Npc1-null and wild-type mice]. Analysis of expression profiles of 86 selected genes using real-time RT-PCR arrays showed a wide-spectrum of alterations in the four genotypes compared to wild-type controls. The changes observed in APP-Tg and Dhet mice are limited to only few genes involved mostly in the regulation of cholesterol metabolism, whereas Npc1-null and ANPC mice showed alterations in the expression profiles of a number of genes regulating cholesterol homeostasis, APP metabolism, vesicular trafficking and cell death mechanism in both hippocampus and cerebellum compared to wild-type mice. Intriguingly, ANPC and Npc1-null mice, with some exceptions, exhibited similar changes, although more genes were differentially expressed in the affected cerebellum than the relatively spared hippocampus. The altered gene profiles were found to match with the corresponding protein levels. These results suggest that lack of Npc1 protein can alter the expression profile of selected transcripts as well as proteins, and

  5. Decoding noises in HIV computational genotyping.

    Science.gov (United States)

    Jia, MingRui; Shaw, Timothy; Zhang, Xing; Liu, Dong; Shen, Ye; Ezeamama, Amara E; Yang, Chunfu; Zhang, Ming

    2017-11-01

    Lack of a consistent and reliable genotyping system can critically impede HIV genomic research on pathogenesis, fitness, virulence, drug resistance, and genomic-based healthcare and treatment. At present, mis-genotyping, i.e., background noises in molecular genotyping, and its impact on epidemic surveillance is unknown. For the first time, we present a comprehensive assessment of HIV genotyping quality. HIV sequence data were retrieved from worldwide published records, and subjected to a systematic genotyping assessment pipeline. Results showed that mis-genotyped cases occurred at 4.6% globally, with some regional and high-risk population heterogeneities. Results also revealed a consistent mis-genotyping pattern in gp120 in all studied populations except the group of men who have sex with men. Our study also suggests novel virus diversities in the mis-genotyped cases. Finally, this study reemphasizes the importance of implementing a standardized genotyping pipeline to avoid genotyping disparity and to advance our understanding of virus evolution in various epidemiological settings. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. MAGNETIC NULL POINTS IN KINETIC SIMULATIONS OF SPACE PLASMAS

    International Nuclear Information System (INIS)

    Olshevsky, Vyacheslav; Innocenti, Maria Elena; Cazzola, Emanuele; Lapenta, Giovanni; Deca, Jan; Divin, Andrey; Peng, Ivy Bo; Markidis, Stefano

    2016-01-01

    We present a systematic attempt to study magnetic null points and the associated magnetic energy conversion in kinetic particle-in-cell simulations of various plasma configurations. We address three-dimensional simulations performed with the semi-implicit kinetic electromagnetic code iPic3D in different setups: variations of a Harris current sheet, dipolar and quadrupolar magnetospheres interacting with the solar wind, and a relaxing turbulent configuration with multiple null points. Spiral nulls are more likely created in space plasmas: in all our simulations except lunar magnetic anomaly (LMA) and quadrupolar mini-magnetosphere the number of spiral nulls prevails over the number of radial nulls by a factor of 3–9. We show that often magnetic nulls do not indicate the regions of intensive energy dissipation. Energy dissipation events caused by topological bifurcations at radial nulls are rather rare and short-lived. The so-called X-lines formed by the radial nulls in the Harris current sheet and LMA simulations are rather stable and do not exhibit any energy dissipation. Energy dissipation is more powerful in the vicinity of spiral nulls enclosed by magnetic flux ropes with strong currents at their axes (their cross sections resemble 2D magnetic islands). These null lines reminiscent of Z-pinches efficiently dissipate magnetic energy due to secondary instabilities such as the two-stream or kinking instability, accompanied by changes in magnetic topology. Current enhancements accompanied by spiral nulls may signal magnetic energy conversion sites in the observational data

  7. Visual and Plastic Arts in Teaching Literacy: Null Curricula?

    Science.gov (United States)

    Wakeland, Robin Gay

    2010-01-01

    Visual and plastic arts in contemporary literacy instruction equal null curricula. Studies show that painting and sculpture facilitate teaching reading and writing (literacy), yet such pedagogy has not been formally adopted into USA curriculum. An example of null curriculum can be found in late 19th - early 20th century education the USA…

  8. Euclidean null controllability of nonlinear infinite delay systems with ...

    African Journals Online (AJOL)

    Sufficient conditions for the Euclidean null controllability of non-linear delay systems with time varying multiple delays in the control and implicit derivative are derived. If the uncontrolled system is uniformly asymptotically stable and if the control system is controllable, then the non-linear infinite delay system is Euclidean null ...

  9. Null infinity and extremal horizons in AdS-CFT

    International Nuclear Information System (INIS)

    Hickling, Andrew; Wiseman, Toby; Lucietti, James

    2015-01-01

    We consider AdS gravity duals to CFT on background spacetimes with a null infinity. Null infinity on the conformal boundary may extend to an extremal horizon in the bulk. For example it does so for Poincaré–AdS, although does not for planar Schwarzschild–AdS. If null infinity does extend into an extremal horizon in the bulk, we show that the bulk near-horizon geometry is determined by the geometry of the boundary null infinity. Hence the ‘infra-red’ geometry of the bulk is fixed by the large scale behaviour of the CFT spacetime. In addition the boundary stress tensor must have a particular decay at null infinity. As an application, we argue that for CFT on asymptotically flat backgrounds, any static bulk dual containing an extremal horizon extending from the boundary null infinity, must have the near-horizon geometry of Poincaré–AdS. We also discuss a class of boundary null infinity that cannot extend to a bulk extremal horizon, although we give evidence that they can extend to an analogous null surface in the bulk which possesses an associated scale-invariant ‘near-geometry’. (paper)

  10. Logarithmic corrections to gravitational entropy and the null energy condition

    Energy Technology Data Exchange (ETDEWEB)

    Parikh, Maulik, E-mail: maulik.parikh@asu.edu; Svesko, Andrew

    2016-10-10

    Using a relation between the thermodynamics of local horizons and the null energy condition, we consider the effects of quantum corrections to the gravitational entropy. In particular, we find that the geometric form of the null energy condition is not affected by the inclusion of logarithmic corrections to the Bekenstein–Hawking entropy.

  11. Logarithmic corrections to gravitational entropy and the null energy condition

    Directory of Open Access Journals (Sweden)

    Maulik Parikh

    2016-10-01

    Full Text Available Using a relation between the thermodynamics of local horizons and the null energy condition, we consider the effects of quantum corrections to the gravitational entropy. In particular, we find that the geometric form of the null energy condition is not affected by the inclusion of logarithmic corrections to the Bekenstein–Hawking entropy.

  12. A new dynamic null model for phylogenetic community structure

    NARCIS (Netherlands)

    Pigot, Alex L; Etienne, Rampal S

    Phylogenies are increasingly applied to identify the mechanisms structuring ecological communities but progress has been hindered by a reliance on statistical null models that ignore the historical process of community assembly. Here, we address this, and develop a dynamic null model of assembly by

  13. ENERGY DISSIPATION IN MAGNETIC NULL POINTS AT KINETIC SCALES

    International Nuclear Information System (INIS)

    Olshevsky, Vyacheslav; Lapenta, Giovanni; Divin, Andrey; Eriksson, Elin; Markidis, Stefano

    2015-01-01

    We use kinetic particle-in-cell and MHD simulations supported by an observational data set to investigate magnetic reconnection in clusters of null points in space plasma. The magnetic configuration under investigation is driven by fast adiabatic flux rope compression that dissipates almost half of the initial magnetic field energy. In this phase powerful currents are excited producing secondary instabilities, and the system is brought into a state of “intermittent turbulence” within a few ion gyro-periods. Reconnection events are distributed all over the simulation domain and energy dissipation is rather volume-filling. Numerous spiral null points interconnected via their spines form null lines embedded into magnetic flux ropes; null point pairs demonstrate the signatures of torsional spine reconnection. However, energy dissipation mainly happens in the shear layers formed by adjacent flux ropes with oppositely directed currents. In these regions radial null pairs are spontaneously emerging and vanishing, associated with electron streams and small-scale current sheets. The number of spiral nulls in the simulation outweighs the number of radial nulls by a factor of 5–10, in accordance with Cluster observations in the Earth's magnetosheath. Twisted magnetic fields with embedded spiral null points might indicate the regions of major energy dissipation for future space missions such as the Magnetospheric Multiscale Mission

  14. On the Robinson theorem and shearfree geodesic null congruences

    International Nuclear Information System (INIS)

    Tafel, J.

    1985-01-01

    Null electromagnetic fields and shearfree geodesic null congruences in curved and flat spacetimes are studied. We point out some mathematical problems connected with the validity of the Robinson theorem. The problem of finding nonanalytic twisting congruences in the Minkowski space is reduced to the construction of holomorphic functions with specific boundary conditions. (orig.)

  15. An omnibus test for the global null hypothesis.

    Science.gov (United States)

    Futschik, Andreas; Taus, Thomas; Zehetmayer, Sonja

    2018-01-01

    Global hypothesis tests are a useful tool in the context of clinical trials, genetic studies, or meta-analyses, when researchers are not interested in testing individual hypotheses, but in testing whether none of the hypotheses is false. There are several possibilities how to test the global null hypothesis when the individual null hypotheses are independent. If it is assumed that many of the individual null hypotheses are false, combination tests have been recommended to maximize power. If, however, it is assumed that only one or a few null hypotheses are false, global tests based on individual test statistics are more powerful (e.g. Bonferroni or Simes test). However, usually there is no a priori knowledge on the number of false individual null hypotheses. We therefore propose an omnibus test based on cumulative sums of the transformed p-values. We show that this test yields an impressive overall performance. The proposed method is implemented in an R-package called omnibus.

  16. The Visible Nulling Coronagraph--Architecture Definition and Technology Development

    Science.gov (United States)

    Shao, Michael; Levine, B. Martin; Wallace, J. Kent; Liu, Duncan T.; Schmidtlin, Edouard; Serabyn, Eugene; Mennesson, Bertrand; Green, Joseph J.; Aguayo, Francisco; Fregoso, S. Felipe; hide

    2005-01-01

    This paper describes the advantages of visible direct detection and spectroscopy of Earth-like extrasolar planets using a nulling coronagraph instrument behind a moderately sized single aperture space telescope. Our concept synthesizes a nulling interferometer by shearing the telescope pupil, with the resultant producing a deep null. We describe nulling configurations that also include methods to mitigate stellar leakage, such as spatial filtering by a coherent array of single mode fibers, and post-starlight suppression wavefront sensing and control. With diffraction limited telescope optics and similar quality components in the optical train (lambda/20), suppression of the starlight to 1e-10 is readily achievable. We describe key features of the architecture and analysis, present latest results of laboratory measurements demonstrating achievable null depth and component development, and discuss future key technical milestones.

  17. Wormholes minimally violating the null energy condition

    Energy Technology Data Exchange (ETDEWEB)

    Bouhmadi-López, Mariam [Departamento de Física, Universidade da Beira Interior, 6200 Covilhã (Portugal); Lobo, Francisco S N; Martín-Moruno, Prado, E-mail: mariam.bouhmadi@ehu.es, E-mail: fslobo@fc.ul.pt, E-mail: pmmoruno@fc.ul.pt [Centro de Astronomia e Astrofísica da Universidade de Lisboa, Campo Grande, Edifício C8, 1749-016 Lisboa (Portugal)

    2014-11-01

    We consider novel wormhole solutions supported by a matter content that minimally violates the null energy condition. More specifically, we consider an equation of state in which the sum of the energy density and radial pressure is proportional to a constant with a value smaller than that of the inverse area characterising the system, i.e., the area of the wormhole mouth. This approach is motivated by a recently proposed cosmological event, denoted {sup t}he little sibling of the big rip{sup ,} where the Hubble rate and the scale factor blow up but the cosmic derivative of the Hubble rate does not [1]. By using the cut-and-paste approach, we match interior spherically symmetric wormhole solutions to an exterior Schwarzschild geometry, and analyse the stability of the thin-shell to linearized spherically symmetric perturbations around static solutions, by choosing suitable properties for the exotic material residing on the junction interface radius. Furthermore, we also consider an inhomogeneous generalization of the equation of state considered above and analyse the respective stability regions. In particular, we obtain a specific wormhole solution with an asymptotic behaviour corresponding to a global monopole.

  18. Energy brands lack vitality

    International Nuclear Information System (INIS)

    Godri, S.; Wilders, E.

    2004-01-01

    The three Dutch energy companies (Nuon, Essent and Eneco Energie) have relatively little brand strength. The brands are not perceived to be sufficiently different from one another and are not valued by consumers. With liberalisation imminent, this is hardly a strong starting point. How can you win over consumers if it is not clear what is on offer? In the business market, decision-makers are better placed to distinguish between brands. However, the brands lack vitality in this sector of the market too. The only consolation is that the situation is by no means exclusive to the Netherlands [nl

  19. Mechanical Forces Exacerbate Periodontal Defects in Bsp-null Mice

    Science.gov (United States)

    Soenjaya, Y.; Foster, B.L.; Nociti, F.H.; Ao, M.; Holdsworth, D.W.; Hunter, G.K.; Somerman, M.J.

    2015-01-01

    Bone sialoprotein (BSP) is an acidic phosphoprotein with collagen-binding, cell attachment, and hydroxyapatite-nucleating properties. BSP expression in mineralized tissues is upregulated at onset of mineralization. Bsp-null (Bsp-/-) mice exhibit reductions in bone mineral density, bone turnover, osteoclast activation, and impaired bone healing. Furthermore, Bsp-/- mice have marked periodontal tissue breakdown, with a lack of acellular cementum leading to periodontal ligament detachment, extensive alveolar bone and tooth root resorption, and incisor malocclusion. We hypothesized that altered mechanical stress from mastication contributes to periodontal destruction observed in Bsp-/- mice. This hypothesis was tested by comparing Bsp-/- and wild-type mice fed with standard hard pellet diet or soft powder diet. Dentoalveolar tissues were analyzed using histology and micro–computed tomography. By 8 wk of age, Bsp-/- mice exhibited molar and incisor malocclusion regardless of diet. Bsp-/- mice with hard pellet diet exhibited high incidence (30%) of severe incisor malocclusion, 10% lower body weight, 3% reduced femur length, and 30% elevated serum alkaline phosphatase activity compared to wild type. Soft powder diet reduced severe incisor malocclusion incidence to 3% in Bsp-/- mice, supporting the hypothesis that occlusal loading contributed to the malocclusion phenotype. Furthermore, Bsp-/- mice in the soft powder diet group featured normal body weight, long bone length, and serum alkaline phosphatase activity, suggesting that tooth dysfunction and malnutrition contribute to growth and skeletal defects reported in Bsp-/- mice. Bsp-/- incisors also erupt at a slower rate, which likely leads to the observed thickened dentin and enhanced mineralization of dentin and enamel toward the apical end. We propose that the decrease in eruption rate is due to a lack of acellular cementum and associated defective periodontal attachment. These data demonstrate the importance of BSP

  20. Glutathione S-Transferase M1 and T1 Null Genotype Frequency ...

    Indian Academy of Sciences (India)

    Bluebird

    2017-10-25

    Oct 25, 2017 ... A comparative analysis with different tribal as well as world ..... T1 and P1) gene polymorphisms with type 2 diabetes mellitus in north .... Houlston R. S. 2000 CYP1A1 polymorphisms and lung cancer risk: a meta-analysis.

  1. Glutathione S-transferase M1 and T1 null genotype frequency ...

    Indian Academy of Sciences (India)

    PREM CHANDRA SUTHAR

    2018-03-24

    Mar 24, 2018 ... A comparative analysis with different tribal as well as world population has also been ...... (GSTM1, T1 and P1) gene polymorphisms with type 2 diabetes mellitus .... from the Spanish Bladder Cancer Study and meta-analyses.

  2. Expression of extracellular matrix components is disrupted in the immature and adult estrogen receptor β-null mouse ovary.

    Directory of Open Access Journals (Sweden)

    Alexandra Zalewski

    Full Text Available Within the ovary, Estrogen Receptor β (ERβ is localized to the granulosa cells of growing follicles. 17β-estradiol (E2 acting via ERβ augments the actions of follicle stimulating hormone in granulosa cells, leading to granulosa cell differentiation and formation of a preovulatory follicle. Adult ERβ-null females are subfertile and possess ovaries with reduced numbers of growing follicles and corpora lutea. Because the majority of E2 production by granulosa cells occurs once puberty is reached, a role for ERβ in the ovary prior to puberty has not been well examined. We now provide evidence that lack of ERβ disrupts gene expression as early as post-natal day (PND 13, and in particular, we identify a number of genes of the extracellular matrix (ECM that are significantly higher in ERβ-null follicles than in wildtype (WT follicles. Considerable changes occur to the ECM occur during normal folliculogenesis to allow for the dramatic growth, cellular differentiation, and reorganization of the follicle from the primary to preovulatory stage. Using quantitative PCR and immunofluorescence, we now show that several ECM genes are aberrantly overexpressed in ERβ-null follicles. We find that Collagen11a1, a protein highly expressed in cartilage, is significantly higher in ERβ-null follicles than WT follicles as early as PND 13, and this heightened expression continues through PND 23-29 into adulthood. Similarly, Nidogen 2, a highly conserved basement membrane glycoprotein, is elevated in ERβ-null follicles at PND 13 into adulthood, and is elevated specifically in the ERβ-null focimatrix, a basal lamina-like matrix located between granulosa cells. Focimatrix laminin and Collagen IV expression were also higher in ERβ-null ovaries than in WT ovaries at various ages. Our findings suggest two novel observations: a that ERβ regulates granulosa cell gene expression ovary prior to puberty, and b that ERβ regulates expression of ECM components in the

  3. Tensionless branes and the null string critical dimension

    International Nuclear Information System (INIS)

    Bozhilov, P.

    1998-01-01

    BRST quantization is carried out for a model of p-branes with second class constraints. After extension of the phase space the constraint algebra coincides with the one of null string when p=1. It is shown that in this case one can or cannot obtain critical dimension for the null string, depending on the choice of the operator ordering and corresponding vacuum states. When p>1, operator orderings leading to critical dimension in the p=1 case are not allowed. Admissible orderings give no restrictions on the dimension of the embedding space-time. Finally, a generalization to supersymmetric null branes is proposed

  4. Emission and null coordinates: geometrical properties and physical construction

    International Nuclear Information System (INIS)

    Coll, Bartolome; Ferrando, Joan J; Morales-Lladosa, Juan A

    2011-01-01

    A Relativistic Positioning System is defined by four clocks (emitters) broadcasting their proper time. Then, every event reached by the signals is naturally labeled by these four times which are the emission coordinates of this event. The coordinate hypersurfaces of the emission coordinates are the future light cones based on the emitter trajectories. For this reason the emission coordinates have been also named null coordinates or light coordinates. Nevertheless, other coordinate systems used in different relativistic contexts have the own right to be named null or light coordinates. Here we analyze when one can say that a coordinate is a null coordinate and when one can say that a coordinate system is null. Moreover, we examine the physical construction and the geometrical properties of several n ull coordinate systems : the emission and the reception coordinates, the radar coordinates, and the Bondi-Sachs coordinates, among others.

  5. Relative null controllability of linear systems with multiple delays in ...

    African Journals Online (AJOL)

    varying multiple delays in state and control are developed. If the uncontrolled system is uniformly asymptotically stable, and if the linear system is controllable, then the linear system is null controllable. Journal of the Nigerian Association of ...

  6. Null canonical formalism 1, Maxwell field. [Poisson brackets, boundary conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wodkiewicz, K [Warsaw Univ. (Poland). Inst. Fizyki Teoretycznej

    1975-01-01

    The purpose of this paper is to formulate the canonical formalism on null hypersurfaces for the Maxwell electrodynamics. The set of the Poisson brackets relations for null variables of the Maxwell field is obtained. The asymptotic properties of the theory are investigated. The Poisson bracket relations for the news-functions of the Maxwell field are computed. The Hamiltonian form of the asymptotic Maxwell equations in terms of these news-functions is obtained.

  7. Null controllability of a cascade system of Schrodinger equations

    Directory of Open Access Journals (Sweden)

    Marcos Lopez-Garcia

    2016-03-01

    Full Text Available This article presents a control problem for a cascade system of two linear N-dimensional Schrodinger equations. We address the problem of null controllability by means of a control supported in a region not satisfying the classical geometrical control condition. The proof is based on the application of a Carleman estimate with degenerate weights to each one of the equations and a careful analysis of the system in order to prove null controllability with only one control force.

  8. Sequential weak continuity of null Lagrangians at the boundary

    Czech Academy of Sciences Publication Activity Database

    Kalamajska, A.; Kraemer, S.; Kružík, Martin

    2014-01-01

    Roč. 49, 3/4 (2014), s. 1263-1278 ISSN 0944-2669 R&D Projects: GA ČR GAP201/10/0357 Institutional support: RVO:67985556 Keywords : null Lagrangians * nonhomogeneous nonlinear mappings * sequential weak/in measure continuity Subject RIV: BA - General Mathematics Impact factor: 1.518, year: 2014 http://library.utia.cas.cz/separaty/2013/MTR/kruzik-sequential weak continuity of null lagrangians at the boundary.pdf

  9. On the geometry of null congruences in general relativity

    International Nuclear Information System (INIS)

    Ahsan, Zafar; Malik, N.P.

    1977-01-01

    Some theorems for the null congruences within the framework of general theory of relativity are given. These theorems are important in themselves as they illustrate the geometric meaning of the spin coefficients. The newly developed Geroch-Held-Penrose (GHP) formalism has been used throughout the investigations. The salient features of GHP formalism that are necessary for the present work are given and these techniques are applied to a pair of null congruences C(l) and C(n). (author)

  10. A parameter set for a double-null DEMO reactor

    International Nuclear Information System (INIS)

    Cooke, P.I.H.

    1987-01-01

    The present study is aimed at commenting on the reactor-relevance of the design principles and technology being proposed for NET. The authors propose that a double-null device serve as a basis for a NET-based demonstration reactor. Calculations are carried out to determine the parameter set for reactors based on the double-null NET design, and the results are presented in tabular form. (U.K.)

  11. Vortical null orbits, repulsive barriers, energy confinement in Kerr metric

    Energy Technology Data Exchange (ETDEWEB)

    Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; De Felice, F

    1978-10-01

    The complete analytical description of the null trajectories in the field of a Kerr naked singularity is given. Two peculiar phenomena are described: the existence of repulsive barriers in the r < O world and the existence of null circular bound orbits which surround the singularity in 'shells'. They distribute around the surface at r = m, which is the position of the horizon in the extreme black-hole case; this suggests that a naked singularity 'remembers' the position of the last horizon.

  12. Ambitwistor strings at null infinity and (subleading) soft limits

    International Nuclear Information System (INIS)

    Geyer, Yvonne; Lipstein, Arthur E; Mason, Lionel

    2015-01-01

    The relationship between BMS symmetries at null infinity and Weinberg's soft theorems for gravitons and photons together with their subleading extensions are developed using ambitwistor string theory. Ambitwistor space is the phase space of complex null geodesics in complexified space-time. We show how it can be canonically identified with the cotangent bundle of complexified null infinity. BMS symmetries of null infinity lift to give a Hamiltonian action on ambitwistor space, both in general dimension and in its twistorial four-dimensional representation. General vertex operators arise from Hamiltonians generating diffeomorphisms of ambitwistor space that determine the scattering from past to future null infinity. When a momentum eigenstate goes soft, the diffeomorphism defined by its leading and its subleading part are extended BMS generators realized in the world sheet conformal field theory of the ambitwistor string. More generally, this gives an explicit perturbative correspondence between the scattering of null geodesics and that of the gravitational field via ambitwistor string theory. (paper)

  13. Nav 1.8-null mice show stimulus-dependent deficits in spinal neuronal activity

    Directory of Open Access Journals (Sweden)

    Wood John N

    2006-02-01

    Full Text Available Abstract Background The voltage gated sodium channel Nav 1.8 has a highly restricted expression pattern to predominantly nociceptive peripheral sensory neurones. Behaviourally Nav 1.8-null mice show an increased acute pain threshold to noxious mechanical pressure and also deficits in inflammatory and visceral, but not neuropathic pain. Here we have made in vivo electrophysiology recordings of dorsal horn neurones in intact anaesthetised Nav 1.8-null mice, in response to a wide range of stimuli to further the understanding of the functional roles of Nav 1.8 in pain transmission from the periphery to the spinal cord. Results Nav 1.8-null mice showed marked deficits in the coding by dorsal horn neurones to mechanical, but not thermal, -evoked responses over the non-noxious and noxious range compared to littermate controls. Additionally, responses evoked to other stimulus modalities were also significantly reduced in Nav 1.8-null mice where the reduction observed to pinch > brush. The occurrence of ongoing spontaneous neuronal activity was significantly less in mice lacking Nav 1.8 compared to control. No difference was observed between groups in the evoked activity to electrical activity of the peripheral receptive field. Conclusion This study demonstrates that deletion of the sodium channel Nav 1.8 results in stimulus-dependent deficits in the dorsal horn neuronal coding to mechanical, but not thermal stimuli applied to the neuronal peripheral receptive field. This implies that Nav 1.8 is either responsible for, or associated with proteins involved in mechanosensation.

  14. A new AQP1 null allele identified in a Gypsy woman who developed an anti-CO3 during her first pregnancy.

    Science.gov (United States)

    Saison, C; Peyrard, T; Landre, C; Ballif, B A; Schlosser, K A; Dettori, I; Chicheportiche, C; Nemeth, P; Cartron, J-P; Arnaud, L

    2012-08-01

    The Colton blood group antigens are carried by the AQP1 water channel. AQP1(-/-) individuals, also known as Colton-null since they express no Colton antigens, do not suffer any apparent clinical consequence but may develop a clinically significant alloantibody (anti-CO3) induced by transfusion or pregnancy. Identification and transfusion support of Colton-null patients are highly challenging, not only due to the extreme rarity of this phenotype, the lack of appropriate reagents in most laboratories, as well as the possibility of confusing it with the recently described CO:-1,-2,3,-4 phenotype where AQP1 is present. This study investigated a new Colton-null case and evaluated three commercially available anti-AQP1s to identify Colton-null red blood cell samples. The Colton-null phenotype was investigated by standard serological techniques, AQP1 sequencing, immunoblot and flow cytometry analyses. We identified and characterized the Colton-null phenotype in a Gypsy woman who developed an anti-CO3 during her first pregnancy. After developing a simple and robust method to sequence AQP1, we showed that she was apparently homozygous for a new AQP1 null allele, AQP1 601delG, whose product is not expressed in her red blood cells. We also established the Colton specificity of three commercially available anti-AQP1s in immunoblot and/or flow cytometry analyses. This Gypsy woman represents the sixth Colton-null case characterized at the serological, genetic and biochemical levels. The validation here of new reagents and methods should facilitate the identification of Colton-null individuals. © 2012 The Author(s). Vox Sanguinis © 2012 International Society of Blood Transfusion.

  15. Different relationships between temporal phylogenetic turnover and phylogenetic similarity and in two forests were detected by a new null model.

    Science.gov (United States)

    Huang, Jian-Xiong; Zhang, Jian; Shen, Yong; Lian, Ju-yu; Cao, Hong-lin; Ye, Wan-hui; Wu, Lin-fang; Bin, Yue

    2014-01-01

    Ecologists have been monitoring community dynamics with the purpose of understanding the rates and causes of community change. However, there is a lack of monitoring of community dynamics from the perspective of phylogeny. We attempted to understand temporal phylogenetic turnover in a 50 ha tropical forest (Barro Colorado Island, BCI) and a 20 ha subtropical forest (Dinghushan in southern China, DHS). To obtain temporal phylogenetic turnover under random conditions, two null models were used. The first shuffled names of species that are widely used in community phylogenetic analyses. The second simulated demographic processes with careful consideration on the variation in dispersal ability among species and the variations in mortality both among species and among size classes. With the two models, we tested the relationships between temporal phylogenetic turnover and phylogenetic similarity at different spatial scales in the two forests. Results were more consistent with previous findings using the second null model suggesting that the second null model is more appropriate for our purposes. With the second null model, a significantly positive relationship was detected between phylogenetic turnover and phylogenetic similarity in BCI at a 10 m×10 m scale, potentially indicating phylogenetic density dependence. This relationship in DHS was significantly negative at three of five spatial scales. This could indicate abiotic filtering processes for community assembly. Using variation partitioning, we found phylogenetic similarity contributed to variation in temporal phylogenetic turnover in the DHS plot but not in BCI plot. The mechanisms for community assembly in BCI and DHS vary from phylogenetic perspective. Only the second null model detected this difference indicating the importance of choosing a proper null model.

  16. MAPK signaling pathways and HDAC3 activity are disrupted during differentiation of emerin-null myogenic progenitor cells

    Directory of Open Access Journals (Sweden)

    Carol M. Collins

    2017-04-01

    Full Text Available Mutations in the gene encoding emerin cause Emery–Dreifuss muscular dystrophy (EDMD. Emerin is an integral inner nuclear membrane protein and a component of the nuclear lamina. EDMD is characterized by skeletal muscle wasting, cardiac conduction defects and tendon contractures. The failure to regenerate skeletal muscle is predicted to contribute to the skeletal muscle pathology of EDMD. We hypothesize that muscle regeneration defects are caused by impaired muscle stem cell differentiation. Myogenic progenitors derived from emerin-null mice were used to confirm their impaired differentiation and analyze selected myogenic molecular pathways. Emerin-null progenitors were delayed in their cell cycle exit, had decreased myosin heavy chain (MyHC expression and formed fewer myotubes. Emerin binds to and activates histone deacetylase 3 (HDAC3. Here, we show that theophylline, an HDAC3-specific activator, improved myotube formation in emerin-null cells. Addition of the HDAC3-specific inhibitor RGFP966 blocked myotube formation and MyHC expression in wild-type and emerin-null myogenic progenitors, but did not affect cell cycle exit. Downregulation of emerin was previously shown to affect the p38 MAPK and ERK/MAPK pathways in C2C12 myoblast differentiation. Using a pure population of myogenic progenitors completely lacking emerin expression, we show that these pathways are also disrupted. ERK inhibition improved MyHC expression in emerin-null cells, but failed to rescue myotube formation or cell cycle exit. Inhibition of p38 MAPK prevented differentiation in both wild-type and emerin-null progenitors. These results show that each of these molecular pathways specifically regulates a particular stage of myogenic differentiation in an emerin-dependent manner. Thus, pharmacological targeting of multiple pathways acting at specific differentiation stages may be a better therapeutic approach in the future to rescue muscle regeneration in vivo.

  17. Noninvasive Genotyping and Mendelian Analysis of Microsatellites in African Savannah Elephants

    DEFF Research Database (Denmark)

    Okello, John Bosco A.; Wittemyer, G.; Rasmussen, H. B.

    2005-01-01

    mismatch error rate of 2.06%, a possible result of null alleles, mutations, genotyping errors, or inaccuracy in maternity assignment. We detected no evidence for large allele dropout, stuttering, or scoring error in the dataset and significant Hardy-Weinberg deviations at only two loci due...

  18. Resistivity at the field null of the FRC plasma

    International Nuclear Information System (INIS)

    Gerwin, R.A.

    1989-01-01

    In the absence of the major destructive instabilities, the configuration time is ultimately determined by particle and flux containment. If the profiles are ''gentle,'' then the anomalous flux-loss rate depends essentially on the anomalous resistivity at the field null. Conventional electrostatic quasi-linear models of anomalous cross-field resistive diffusivity are based upon the use of rvec E x rvec B drift velocities, and hence break down at the magnetic field null. In this paper, an electromagnetic treatment valid at the field null is developed, based upon the presence of flute-parity perturbations. An expression for anomalous resistivity at the field null in the quasi-linear approximation is derived by averaging in the ignorable direction over the random phases of the perturbations. The expression is valid for arbitrary (non-local) radial shapes of the perturbing modes (for example, the eigenfunctions need not be centered at the field null), and for an arbitrary ratio of real frequency to growth rate. The effective resistivity due to flute perturbations of the MHD type will be considered. 1 ref

  19. Evaluation of null-point detection methods on simulation data

    Science.gov (United States)

    Olshevsky, Vyacheslav; Fu, Huishan; Vaivads, Andris; Khotyaintsev, Yuri; Lapenta, Giovanni; Markidis, Stefano

    2014-05-01

    We model the measurements of artificial spacecraft that resemble the configuration of CLUSTER propagating in the particle-in-cell simulation of turbulent magnetic reconnection. The simulation domain contains multiple isolated X-type null-points, but the majority are O-type null-points. Simulations show that current pinches surrounded by twisted fields, analogous to laboratory pinches, are formed along the sequences of O-type nulls. In the simulation, the magnetic reconnection is mainly driven by the kinking of the pinches, at spatial scales of several ion inertial lentghs. We compute the locations of magnetic null-points and detect their type. When the satellites are separated by the fractions of ion inertial length, as it is for CLUSTER, they are able to locate both the isolated null-points, and the pinches. We apply the method to the real CLUSTER data and speculate how common are pinches in the magnetosphere, and whether they play a dominant role in the dissipation of magnetic energy.

  20. Visible nulling coronagraphy testbed development for exoplanet detection

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert A.; Vasudevan, Gopal; Thompson, Patrick; Chen, Andrew; Petrone, Peter; Booth, Andrew; Madison, Timothy; Bolcar, Matthew; Noecker, M. Charley; Kendrick, Stephen; Melnick, Gary; Tolls, Volker

    2010-07-01

    Three of the recently completed NASA Astrophysics Strategic Mission Concept (ASMC) studies addressed the feasibility of using a Visible Nulling Coronagraph (VNC) as the prime instrument for exoplanet science. The VNC approach is one of the few approaches that works with filled, segmented and sparse or diluted aperture telescope systems and thus spans the space of potential ASMC exoplanet missions. NASA/Goddard Space Flight Center (GSFC) has a well-established effort to develop VNC technologies and has developed an incremental sequence of VNC testbeds to advance the this approach and the technologies associated with it. Herein we report on the continued development of the vacuum Visible Nulling Coronagraph testbed (VNT). The VNT is an ultra-stable vibration isolated testbed that operates under high bandwidth closed-loop control within a vacuum chamber. It will be used to achieve an incremental sequence of three visible light nulling milestones of sequentially higher contrasts of 108, 109 and 1010 at an inner working angle of 2*λ/D and ultimately culminate in spectrally broadband (>20%) high contrast imaging. Each of the milestones, one per year, is traceable to one or more of the ASMC studies. The VNT uses a modified Mach-Zehnder nulling interferometer, modified with a modified "W" configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. Discussed will be the optical configuration laboratory results, critical technologies and the null sensing and control approach.

  1. Tolerance analysis of null lenses using an end-use system performance criterion

    Science.gov (United States)

    Rodgers, J. Michael

    2000-07-01

    An effective method of assigning tolerances to a null lens is to determine the effects of null-lens fabrication and alignment errors on the end-use system itself, not simply the null lens. This paper describes a method to assign null- lens tolerances based on their effect on any performance parameter of the end-use system.

  2. Null but not void: considerations for hypothesis testing.

    Science.gov (United States)

    Shaw, Pamela A; Proschan, Michael A

    2013-01-30

    Standard statistical theory teaches us that once the null and alternative hypotheses have been defined for a parameter, the choice of the statistical test is clear. Standard theory does not teach us how to choose the null or alternative hypothesis appropriate to the scientific question of interest. Neither does it tell us that in some cases, depending on which alternatives are realistic, we may want to define our null hypothesis differently. Problems in statistical practice are frequently not as pristinely summarized as the classic theory in our textbooks. In this article, we present examples in statistical hypothesis testing in which seemingly simple choices are in fact rich with nuance that, when given full consideration, make the choice of the right hypothesis test much less straightforward. Published 2012. This article is a US Government work and is in the public domain in the USA.

  3. sirt1-null mice develop an autoimmune-like condition

    International Nuclear Information System (INIS)

    Sequeira, Jedon; Boily, Gino; Bazinet, Stephanie; Saliba, Sarah; He Xiaohong; Jardine, Karen; Kennedy, Christopher; Staines, William; Rousseaux, Colin; Mueller, Rudi; McBurney, Michael W.

    2008-01-01

    The sirt1 gene encodes a protein deacetylase with a broad spectrum of reported substrates. Mice carrying null alleles for sirt1 are viable on outbred genetic backgrounds so we have examined them in detail to identify the biological processes that are dependent on SIRT1. Sera from adult sirt1-null mice contain antibodies that react with nuclear antigens and immune complexes become deposited in the livers and kidneys of these animals. Some of the sirt1-null animals develop a disease resembling diabetes insipidus when they approach 2 years of age although the relationship to the autoimmunity remains unclear. We interpret these observations as consistent with a role for SIRT1 in sustaining normal immune function and in this way delaying the onset of autoimmune disease

  4. Unicorns do exist: a tutorial on "proving" the null hypothesis.

    Science.gov (United States)

    Streiner, David L

    2003-12-01

    Introductory statistics classes teach us that we can never prove the null hypothesis; all we can do is reject or fail to reject it. However, there are times when it is necessary to try to prove the nonexistence of a difference between groups. This most often happens within the context of comparing a new treatment against an established one and showing that the new intervention is not inferior to the standard. This article first outlines the logic of "noninferiority" testing by differentiating between the null hypothesis (that which we are trying to nullify) and the "nill" hypothesis (there is no difference), reversing the role of the null and alternate hypotheses, and defining an interval within which groups are said to be equivalent. We then work through an example and show how to calculate sample sizes for noninferiority studies.

  5. ISCO and Principal Null Congruences in Extremal Kerr Spacetime

    International Nuclear Information System (INIS)

    Pradhan, Parthapratim

    2012-01-01

    The effective potential in universal like coordinates(U, V, θ, φ), which are smooth across the event horizon is derived and investigated the ISCO(Innermost Stable Circular Orbits) explicitly in these coordinates for extremal Kerr spacetime. Extremization of the effective potential for timelike circular orbit shows that the existence of a stable circular geodesics in the extremal spacetime for direct orbit, precisely on the event horizon in terms of the radial coordinate which coincides with the principal null geodesic congruences of the event horizon. These null geodesic congruences mold themselves to the spacetime curvature in such a way that Weyl conformal tensor and its dual are vanished, that is why they are in-fact doubly degenerate principal null congruences.

  6. Phase-space lagrangians for null spinning strings

    International Nuclear Information System (INIS)

    Barcelos-Neto, J.; Ruiz-Altaba, M.; Ramirez, C.

    1990-01-01

    The striking fact that normal-ordered null strings have the same critical dimension as their usual non-zero tension siblings can be understood from the observation that one must, in the tensionless case, keep all the conjugate momenta as independent dynamical variables, thus doubling the number of physical degrees of freedom. The fermionic momenta give rise to a second-class constraint which cannot be solved covariantly, but can be successfully incorporated into the first-class constraint algebra after gauge-fixing. The ghost contributions to the anomaly consist of two b-c (and also two β-γ systems in the supersymmetric case), of the single Virasoro sub(super)algebra for the closed null (spinning) string. In the appropriate gauge, the null (super)string is (super)chiral. (orig.)

  7. Toll-like receptor 4 mutant and null mice retain morphine-induced tolerance, hyperalgesia, and physical dependence.

    Directory of Open Access Journals (Sweden)

    Theresa Alexandra Mattioli

    Full Text Available The innate immune system modulates opioid-induced effects within the central nervous system and one target that has received considerable attention is the toll-like receptor 4 (TLR4. Here, we examined the contribution of TLR4 in the development of morphine tolerance, hyperalgesia, and physical dependence in two inbred mouse strains: C3H/HeJ mice which have a dominant negative point mutation in the Tlr4 gene rendering the receptor non-functional, and B10ScNJ mice which are TLR4 null mutants. We found that neither acute antinociceptive response to a single dose of morphine, nor the development of analgesic tolerance to repeated morphine treatment, was affected by TLR4 genotype. Likewise, opioid induced hyperalgesia and opioid physical dependence (assessed by naloxone precipitated withdrawal were not altered in TLR4 mutant or null mice. We also examined the behavioural consequence of two stereoisomers of naloxone: (- naloxone, an opioid receptor antagonist, and (+ naloxone, a purported antagonist of TLR4. Both stereoisomers of naloxone suppressed opioid induced hyperalgesia in wild-type control, TLR4 mutant, and TLR4 null mice. Collectively, our data suggest that TLR4 is not required for opioid-induced analgesic tolerance, hyperalgesia, or physical dependence.

  8. Indirect comparison of the antiviral efficacy of peginterferon alpha 2a plus ribavirin used with or without simeprevir in genotype 4 hepatitis C virus infection, where common comparator study arms are lacking: a special application of the matching adjusted indirect comparison methodology.

    Science.gov (United States)

    Van Sanden, Suzy; Pisini, Marta; Duchesne, Inge; Mehnert, Angelika; Belsey, Jonathan

    2016-01-01

    The need to assess relative efficacy in the absence of comparative clinical trials is a problem that is often encountered in economic modeling. The use of matching adjusted indirect comparison (MAIC) in this situation has been suggested. We present the results of a MAIC used to evaluate the incremental benefit offered by adding simeprevir (SMV) to standard therapy in the treatment of patients infected with genotype 4 hepatitis C virus (HCV). Individual patient data for a single arm study evaluating the use of SMV with peginterferon alfa 2a + ribavirin (PR) in genotype 4 HCV were available (RESTORE study). A systematic literature review was used to identify studies of PR alone used in the same patient group. By applying the inclusion criteria for each study in turn to the RESTORE dataset and then applying the published MAIC covariate matching algorithm, a series of pseudosamples from RESTORE were generated. After assessment of the matching outcomes, the best matched comparisons were used to derive estimates of efficacy for SMV + PR in patients equivalent to those participating in the PR trial. Five potential comparator studies were identified. After applying the matching process, two emerged as offering the greatest equivalence with the generated RESTORE pseudosamples and were used to estimate SMV + PR efficacy, expressed as the percentage of patients achieving sustained viral response (SVR). In one comparison, SVR in the SMV + PR group was 85% versus 63% for PR alone. In the second comparison, the corresponding SVRs were 77% and 44% respectively. After matching for varying baseline characteristics, both comparisons of RESTORE versus studies of PR alone yielded a benefit for SMV + PR vs PR alone in genotype 4 HCV-infected patients. The incremental gain in SVR associated with use of SMV ranged from 22% to 33%. In the absence of direct comparative studies, the MAIC gives a better perspective than simple comparison of absolute SVR from individual

  9. (AMMI) and genotype by environment interaction

    African Journals Online (AJOL)

    SARAH

    2014-04-30

    Apr 30, 2014 ... Background and justification: Lack of stable high yielding cultivars is one ... of advanced finger millet genotypes evaluated in multiple environments, and (ii) identify stable high yielding .... for interaction principal component axis (IPCA) n, γgn ..... Table 2: Analysis of variance for grain yield using AMMI model.

  10. Testing the null hypothesis: the forgotten legacy of Karl Popper?

    Science.gov (United States)

    Wilkinson, Mick

    2013-01-01

    Testing of the null hypothesis is a fundamental aspect of the scientific method and has its basis in the falsification theory of Karl Popper. Null hypothesis testing makes use of deductive reasoning to ensure that the truth of conclusions is irrefutable. In contrast, attempting to demonstrate the new facts on the basis of testing the experimental or research hypothesis makes use of inductive reasoning and is prone to the problem of the Uniformity of Nature assumption described by David Hume in the eighteenth century. Despite this issue and the well documented solution provided by Popper's falsification theory, the majority of publications are still written such that they suggest the research hypothesis is being tested. This is contrary to accepted scientific convention and possibly highlights a poor understanding of the application of conventional significance-based data analysis approaches. Our work should remain driven by conjecture and attempted falsification such that it is always the null hypothesis that is tested. The write up of our studies should make it clear that we are indeed testing the null hypothesis and conforming to the established and accepted philosophical conventions of the scientific method.

  11. Euclidean null controllability of perturbed infinite delay systems with ...

    African Journals Online (AJOL)

    Euclidean null controllability of perturbed infinite delay systems with limited control. ... Open Access DOWNLOAD FULL TEXT ... The results are established by placing conditions on the perturbation function which guarantee that, if the linear control base system is completely Euclidean controllable, then the perturbed system ...

  12. Euclidean null controllability of linear systems with delays in state ...

    African Journals Online (AJOL)

    Sufficient conditions are developed for the Euclidean controllability of linear systems with delay in state and in control. Namely, if the uncontrolled system is uniformly asymptotically stable and the control equation proper, then the control system is Euclidean null controllable. Journal of the Nigerian Association of ...

  13. Future null infinity of Robertson-Walker spacetimes

    International Nuclear Information System (INIS)

    Moreschi, O.M.

    1988-08-01

    The future null infinity for all non-contracting Robertson-Walker space time is studied systematically. A theorem is proved which establishes the expected relation between the nature of J + and the appearance or absence of cosmic event horizons. (author). 7 refs, 1 tab

  14. The Many Null Distributions of Person Fit Indices.

    Science.gov (United States)

    Molenaar, Ivo W.; Hoijtink, Herbert

    1990-01-01

    Statistical properties of person fit indices are reviewed as indicators of the extent to which a person's score pattern is in agreement with a measurement model. Distribution of a fit index and ability-free fit evaluation are discussed. The null distribution was simulated for a test of 20 items. (SLD)

  15. Spatial and null infinity via advanced and retarded conformal factors

    International Nuclear Information System (INIS)

    Hayward, Sean A.

    2003-01-01

    A new approach to space-time asymptotics is presented, refining Penrose's idea of conformal transformations with infinity represented by the conformal boundary of space-time. It is proposed that the Penrose conformal factor be a product of advanced and retarded conformal factors, which asymptotically relate physical and conformal null coordinates and vanish at future and past null infinity respectively. A refined definition of asymptotic flatness at both spatial and null infinity is given, including that the conformal boundary is locally a light cone, with spatial infinity as the vertex. It is shown how to choose the conformal factors so that this asymptotic light cone is locally a metric light cone. The theory is implemented in the spin-coefficient (or null-tetrad) formalism by a joint transformation of the spin-metric and spin-basis (or metric and tetrad). Asymptotic regularity conditions are proposed, based on the conformal boundary locally being a smoothly embedded metric light cone. These conditions ensure that the Bondi-Sachs energy-flux integrals of ingoing and outgoing gravitational radiation decay at spatial infinity such that the total radiated energy is finite, and that the Bondi-Sachs energy-momentum has a unique limit at spatial infinity, coinciding with the uniquely rendered ADM energy-momentum

  16. Red hair is the null phenotype of MC1R.

    Science.gov (United States)

    Beaumont, Kimberley A; Shekar, Sri N; Cook, Anthony L; Duffy, David L; Sturm, Richard A

    2008-08-01

    The Melanocortin-1 Receptor (MC1R) is a G-protein coupled receptor, which is responsible for production of the darker eumelanin pigment and the tanning response. The MC1R gene has many polymorphisms, some of which have been linked to variation in pigmentation phenotypes within human populations. In particular, the p.D84E, p.R151C, p.R160W and p.D294 H alleles have been strongly associated with red hair, fair skin and increased skin cancer risk. These red hair colour (RHC) variants are relatively well described and are thought to result in altered receptor function, while still retaining varying levels of signaling ability in vitro. The mouse Mc1r null phenotype is yellow fur colour, the p.R151C, p.R160W and p.D294 H alleles were able to partially rescue this phenotype, leading to the question of what the true null phenotype of MC1R would be in humans. Due to the rarity of MC1R null alleles in human populations, they have only been found in the heterozygous state until now. We report here the first case of a homozygous MC1R null individual, phenotypic analysis indicates that red hair and fair skin is found in the absence of MC1R function.

  17. On the null distribution of Bayes factors in linear regression

    Science.gov (United States)

    We show that under the null, the 2 log (Bayes factor) is asymptotically distributed as a weighted sum of chi-squared random variables with a shifted mean. This claim holds for Bayesian multi-linear regression with a family of conjugate priors, namely, the normal-inverse-gamma prior, the g-prior, and...

  18. Magnetic Reconnection at a Three-dimensional Solar Null Point

    DEFF Research Database (Denmark)

    Frederiksen, Jacob Trier; Baumann, Gisela; Galsgaard, Klaus

    2012-01-01

    Using a specific solar null point reconnection case studied by Masson et al (2009; ApJ 700, 559) we investigate the dependence of the reconnection rate on boundary driving speed, numerical resolution, type of resistivity (constant or numerical), and assumed stratification (constant density or sol...

  19. Null point of discrimination in crustacean polarisation vision.

    Science.gov (United States)

    How, Martin J; Christy, John; Roberts, Nicholas W; Marshall, N Justin

    2014-07-15

    The polarisation of light is used by many species of cephalopods and crustaceans to discriminate objects or to communicate. Most visual systems with this ability, such as that of the fiddler crab, include receptors with photopigments that are oriented horizontally and vertically relative to the outside world. Photoreceptors in such an orthogonal array are maximally sensitive to polarised light with the same fixed e-vector orientation. Using opponent neural connections, this two-channel system may produce a single value of polarisation contrast and, consequently, it may suffer from null points of discrimination. Stomatopod crustaceans use a different system for polarisation vision, comprising at least four types of polarisation-sensitive photoreceptor arranged at 0, 45, 90 and 135 deg relative to each other, in conjunction with extensive rotational eye movements. This anatomical arrangement should not suffer from equivalent null points of discrimination. To test whether these two systems were vulnerable to null points, we presented the fiddler crab Uca heteropleura and the stomatopod Haptosquilla trispinosa with polarised looming stimuli on a modified LCD monitor. The fiddler crab was less sensitive to differences in the degree of polarised light when the e-vector was at -45 deg than when the e-vector was horizontal. In comparison, stomatopods showed no difference in sensitivity between the two stimulus types. The results suggest that fiddler crabs suffer from a null point of sensitivity, while stomatopods do not. © 2014. Published by The Company of Biologists Ltd.

  20. Null Lens Assembly for X-Ray Mirror Segments

    Science.gov (United States)

    Robinson, David W.

    2011-01-01

    A document discusses a null lens assembly that allows laser interferometry of 60 deg. slumped glass mirror segments used in x-ray mirrors. The assembly consists of four lenses in precise alignment to each other, with incorporated piezoelectric nanometer stepping actuators to position the lenses in six degrees of freedom for positioning relative to each other.

  1. Self-Nulling Beam Combiner Using No External Phase Inverter

    Science.gov (United States)

    Bloemhof, Eric E.

    2010-01-01

    A self-nulling beam combiner is proposed that completely eliminates the phase inversion subsystem from the nulling interferometer, and instead uses the intrinsic phase shifts in the beam splitters. Simplifying the flight instrument in this way will be a valuable enhancement of mission reliability. The tighter tolerances on R = T (R being reflection and T being transmission coefficients) required by the self-nulling configuration actually impose no new constraints on the architecture, as two adaptive nullers must be situated between beam splitters to correct small errors in the coatings. The new feature is exploiting the natural phase shifts in beam combiners to achieve the 180 phase inversion necessary for nulling. The advantage over prior art is that an entire subsystem, the field-flipping optics, can be eliminated. For ultimate simplicity in the flight instrument, one might fabricate coatings to very high tolerances and dispense with the adaptive nullers altogether, with all their moving parts, along with the field flipper subsystem. A single adaptive nuller upstream of the beam combiner may be required to correct beam train errors (systematic noise), but in some circumstances phase chopping reduces these errors substantially, and there may be ways to further reduce the chop residuals. Though such coatings are beyond the current state of the art, the mechanical simplicity and robustness of a flight system without field flipper or adaptive nullers would perhaps justify considerable effort on coating fabrication.

  2. Visible Nulling Coronagraphy for Exo-Planetary Detection and Characterization

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Woodruff, Robert; Vasudevan, Gopal; Shao, Mike; Levine, Martin; Melnick, Gary; Tolls, Volker; Petrone, Peter; Dogoda, Peter; Duval, Julia; Ge, Jian

    Visible Nulling Coronagraphy (VNC) is the proposed method of detecting and characterizing exo-solar Jovian planets (null depth 10-9) for the proposed NASA's Extrasolar Planetary Imaging Coronagraph (EPIC) Clampin & Lyon 2004 and is an approach under evaluation for NASA's Terrestrial Planet Finder (TPF) mission. The VNC approach uses a single unobscured filled-aperture telescope and splits, via a 50:50 beamsplitter, its re-imaged pupil into two paths within a Mach-Zender interferometer. An achromatic PI phase shift is imposed onto one beam path and the two paths are laterally sheared with respect to each other. The two beams are recombined at a second 50:50 beamsplitter. The net effect is that the on axis (stellar) light is transmitted out of the bright interferometer arm while the off-axis (planetary) light is transmitted out of the nulled interferometer arm. The bright output is used for fine pointing control and coarse wavefront control. The nulled output is relayed to the science camera for science imagery and fine wavefront control. The actual transmission pattern, projected on the sky, follows a θ^2 pattern for a single shear, θ^4 for a double shear, with the spacing of the successive maxima proportional to the inverse of the relative lateral shear. Combinations of shears and spacecraft rolls build up the spatial frequency content of the sky transmission pattern in the same manner as imaging interferometer builds up the spatial frequency content of the image.

  3. Shaping Up the Practice of Null Hypothesis Significance Testing.

    Science.gov (United States)

    Wainer, Howard; Robinson, Daniel H.

    2003-01-01

    Discusses criticisms of null hypothesis significance testing (NHST), suggesting that historical use of NHST was reasonable, and current users should read Sir Ronald Fisher's applied work. Notes that modifications to NHST and interpretations of its outcomes might better suit the needs of modern science. Concludes that NHST is most often useful as…

  4. Relative controllability and null controllability of linear delay systems ...

    African Journals Online (AJOL)

    Necessary and sufficient conditions are established for the relative, absolute controllability and null controllability of the generalized linear delay system and its discrete prototype. The paper presents illuminating examples on previous controllability results by Manitius and Olbrot [7] and carries over the results of Onwuatu [8] ...

  5. A model for electron currents near a field null

    International Nuclear Information System (INIS)

    Stark, R.A.; Miley, G.H.

    1987-01-01

    The fluid approximation is invalid near a field null, since the local electron orbit size and the magnetic scale length are comparable. To model the electron currents in this region we propose a single equation of motion describing the bulk electron dynamics. The equation applies to the plasma within one thermal orbit size of the null. The region is treated as unmagnetized; electrons are accelerated by the inductive electric field and drag on ions; damping is provided by viscosity due to electrons and collisions with ions. Through variational calculations and a particle tracking code for electrons, the size of the terms in the equation of motion have been estimated. The resulting equation of motion combines with Faraday's Law to produce a governing equation which implicitly contains the self inductive field of the electrons. This governing equation predicts that viscosity prevents complete cancellation of the ion current density by the electrons in the null region. Thus electron dynamics near the field null should not prevent the formation and deepening of field reversal using neutral-beam injection

  6. A comment on the null geodesic equations in Schwarzschild geometry

    International Nuclear Information System (INIS)

    Rosa, M.A.F.; Rodrigues Junior, W.A.

    1986-01-01

    An integration of the null geodesic equations in the Schwarzschild geometry, which is valid to first order in GM/Rc 2 is presented. The solution is compared with others published in the literature and their range of validity is analysed. Some misunderstandings are also clarified. (Author) [pt

  7. A CLOSER LOOK AT (LACK OF OBVIATION PHENOMENA IN ROMANIAN SUBJUNCTIVE COMPLEMENTS

    Directory of Open Access Journals (Sweden)

    Maria Aurelia Cotfas

    2011-05-01

    Full Text Available The paper looks at Romanian subjunctive complements selected by volitional verbs and considers the interpretation of their null subjects and why – unlike the case of other Romance languages – these can co-refer with a main clause antecedent (what has been called “lack of obviation” in the literature. What we want to show (against claims made by Roussou 2001 and Landau 2004 is that null subject ca-subjunctives in Romanian do not trigger obviation (disjoint subjects and that obviation effects in such contexts can appear not because of ca, but in cases where the subject of the subjunctive complement is an overt 3rd person pronoun whose phi-features match those of the main clause subject. Supporting evidence for the different interpretation of null vs. overt pronouns comes from Reinhart’s (1999, 2000 variable binding vs. co-valuation (Rule I and Ariel’s (1991, 1994 Accessibility Theory.

  8. A closer look at (lack of obviation phenomena in Romanian subjunctive complements

    Directory of Open Access Journals (Sweden)

    Maria Aurelia Cotfas

    2011-01-01

    Full Text Available The paper looks at Romanian subjunctive complements selected by volitional verbs and considers the interpretation of their null subjects and why – unlike the case of other Romance languages – these can co-refer with a main clause antecedent (what has been called “lack of obviation” in the literature. What we want to show (against claims made by Roussou 2001 and Landau 2004 is that null subject ca-subjunctives in Romanian do not trigger obviation (disjoint subjects and that obviation effects in such contexts can appear not because of ca, but in cases where the subject of the subjunctive complement is an overt 3rd person pronoun whose phi-features match those of the main clause subject. Supporting evidence for the different interpretation of null vs. overt pronouns comes from Reinhart’s (1999, 2000 variable binding vs. co-valuation (Rule I and Ariel’s (1991, 1994 Accessibility Theory.

  9. Maxwell fields and shear-free null geodesic congruences

    International Nuclear Information System (INIS)

    Newman, Ezra T

    2004-01-01

    We study and report on the class of vacuum Maxwell fields in Minkowski space that possess a non-degenerate, diverging, principal null vector field (null eigenvector field of the Maxwell tensor) that is tangent to a shear-free null geodesics congruence. These congruences can be either surface forming (the tangent vectors being proportional to gradients) or not, i.e., the twisting congruences. In the non-twisting case, the associated Maxwell fields are precisely the Lienard-Wiechert fields, i.e., those Maxwell fields arising from an electric monopole moving on an arbitrary worldline. The null geodesic congruence is given by the generators of the light-cones with apex on the worldline. The twisting case is much richer, more interesting and far more complicated. In a twisting subcase, where our main interests lie, the following strange interpretation can be given. If we allow the real Minkowski space to be complexified so that the real Minkowski coordinates x a take complex values, i.e., x a → z a = x a + iy a with complex metric g η ab dz a dz b , the real vacuum Maxwell equations can be extended into the complex space and rewritten as curl W=i W radical, div W=0 with W=E+iB. This subcase of Maxwell fields can then be extended into the complex space so as to have as source, a complex analytic worldline, i.e., to now become complex Lienard-Wiechart fields. When viewed as real fields on the real Minkowski space (z a = x a ), they possess a real principal null vector that is shear-free but twisting and diverging. The twist is a measure of how far the complex worldline is from the real 'slice'. Most Maxwell fields in this subcase are asymptotically flat with a time-varying set of electric and magnetic moments, all depending on the complex displacements and the complex velocities

  10. Comprehensive Analysis of the 16p11.2 Deletion and Null Cntnap2 Mouse Models of Autism Spectrum Disorder.

    Directory of Open Access Journals (Sweden)

    Daniela Brunner

    Full Text Available Autism spectrum disorder comprises several neurodevelopmental conditions presenting symptoms in social communication and restricted, repetitive behaviors. A major roadblock for drug development for autism is the lack of robust behavioral signatures predictive of clinical efficacy. To address this issue, we further characterized, in a uniform and rigorous way, mouse models of autism that are of interest because of their construct validity and wide availability to the scientific community. We implemented a broad behavioral battery that included but was not restricted to core autism domains, with the goal of identifying robust, reliable phenotypes amenable for further testing. Here we describe comprehensive findings from two known mouse models of autism, obtained at different developmental stages, using a systematic behavioral test battery combining standard tests as well as novel, quantitative, computer-vision based systems. The first mouse model recapitulates a deletion in human chromosome 16p11.2, found in 1% of individuals with autism. The second mouse model harbors homozygous null mutations in Cntnap2, associated with autism and Pitt-Hopkins-like syndrome. Consistent with previous results, 16p11.2 heterozygous null mice, also known as Del(7Slx1b-Sept14Aam weighed less than wild type littermates displayed hyperactivity and no social deficits. Cntnap2 homozygous null mice were also hyperactive, froze less during testing, showed a mild gait phenotype and deficits in the three-chamber social preference test, although less robust than previously published. In the open field test with exposure to urine of an estrous female, however, the Cntnap2 null mice showed reduced vocalizations. In addition, Cntnap2 null mice performed slightly better in a cognitive procedural learning test. Although finding and replicating robust behavioral phenotypes in animal models is a challenging task, such functional readouts remain important in the development of

  11. A Comparison of Plasma Performance Between Single-Null and Double-Null Configurations During Elming H-Mode

    International Nuclear Information System (INIS)

    Petrie, T.W.; Fenstermacher, M.E.; Allen, S.L.; Carlstrom, T.N.; Gohil, P.; Groebner, R.J.; Greenfield, C.M.; Hyatt, A.W.; Lasnier, C.J.; La Haye, R.J.; Leonard, A.W.; Mahdavi, M.A.; Osborne, T.H.; Porter, G.D.; Rhodes, T.L.; Thomas, D.M.; Watkins, J.G.; West, W.P.; Wolf, N.S.

    1999-01-01

    Tokamak plasma performance generally improves with increased shaping of the plasma cross section, such as higher elongation and higher triangularity. The stronger shaping, especially higher triangularity, leads to changes in the magnetic topology of the divertor. Because there are engineering and divertor physics issues associated with changes in the details of the divertor flux geometry, especially as the configuration transitions from a single-null (SN) divertor to a marginally balanced double-null (DN) divertor, we have undertaken a systematic evaluation of the plasma characteristics as the magnetic geometry is varied, particularly with respect to (1) energy confinement, (2) the response of the plasma to deuterium gas fueling, (3) the operational density range for the ELMing H-mode, and (4) heat flux sharing by the diverters. To quantify the degree of divertor imbalance (or equivalently, to what degree the shape is double-null or single-null), we define a parameter DRSEP. DRSEP is taken as the radial distance between the upper divertor separatrix and the lower divertor separatrix, as determined at the outboard midplane. For example, if DRSEP=O, the configuration is a magnetically balanced DN; if DRSEP = +1.0 cm, the divertor configuration is biased toward the upper divertor. Three examples are shown in Fig. 1. In the following discussions, VB drift is directed toward the lower divertor

  12. Detection of long nulls in PSR B1706-16, a pulsar with large timing irregularities

    Science.gov (United States)

    Naidu, Arun; Joshi, Bhal Chandra; Manoharan, P. K.; Krishnakumar, M. A.

    2018-04-01

    Single pulse observations, characterizing in detail, the nulling behaviour of PSR B1706-16 are being reported for the first time in this paper. Our regular long duration monitoring of this pulsar reveals long nulls of 2-5 h with an overall nulling fraction of 31 ± 2 per cent. The pulsar shows two distinct phases of emission. It is usually in an active phase, characterized by pulsations interspersed with shorter nulls, with a nulling fraction of about 15 per cent, but it also rarely switches to an inactive phase, consisting of long nulls. The nulls in this pulsar are concurrent between 326.5 and 610 MHz. Profile mode changes accompanied by changes in fluctuation properties are seen in this pulsar, which switches from mode A before a null to mode B after the null. The distribution of null durations in this pulsar is bimodal. With its occasional long nulls, PSR B1706-16 joins the small group of intermediate nullers, which lie between the classical nullers and the intermittent pulsars. Similar to other intermediate nullers, PSR B1706-16 shows high timing noise, which could be due to its rare long nulls if one assumes that the slowdown rate during such nulls is different from that during the bursts.

  13. N-ethyl-N-nitrosourea-induced null mutation at the mouse Car-2 locus: An animal model for human carbonic anhydrase II deficiency syndrome

    International Nuclear Information System (INIS)

    Lewis, S.E.; Barnett, L.B.; Erickson, R.P.; Venta, P.J.; Tashian, R.E.

    1988-01-01

    Electrophoretic screening of (C57BL/6J x DBA/2J)F 1 progeny of male mice treated with N-ethyl-N-nitrosourea revealed a mouse that lacked the paternal carbonic anhydrase II (Ca II). Breeding tests showed that this trait was heritable and due to a null mutation at the Car-2 locus on chromosome 3. Like humans with the same inherited enzyme defect, animals homozygous for the new null allele are runted and have renal tubular acidosis. However, the prominent osteopetrosis found in humans with CA II deficiency could be detected even in very old homozygous null mice. A molecular analysis of the deficient mice shows that the mutant gene is not deleted and is transcribed. The CA II protein, which is normally expressed in most tissues, could not be detected by immunodiffusion analysis in any tissues of the CA II-deficient mice, suggesting a nonsense or a missense mutation at the Car-2 locus

  14. APOE Genotyping, Cardiovascular Disease

    Science.gov (United States)

    ... Resources For Health Professionals Subscribe Search APOE Genotyping, Cardiovascular Disease Send Us Your Feedback Choose Topic At a ... help understand the role of genetic factors in cardiovascular disease . However, the testing is sometimes used in clinical ...

  15. Radiosensitivity of fingermillet genotypes

    Energy Technology Data Exchange (ETDEWEB)

    Raveendran, T S; Nagarajan, C; Appadurai, R; Prasad, M N; Sundaresan, N [Tamil Nadu Agricultural Univ., Coimbatore (India)

    1984-07-01

    Varietal differences in radiosensitivity were observed in a study involving 4 genotypes of fingermillet (Eleusine coracana (Linn.) Gaertn.) subjected to gamma-irradiation. Harder seeds were found to tolerate a higher dose of the mutagen.

  16. Nonparametric Regression Estimation for Multivariate Null Recurrent Processes

    Directory of Open Access Journals (Sweden)

    Biqing Cai

    2015-04-01

    Full Text Available This paper discusses nonparametric kernel regression with the regressor being a \\(d\\-dimensional \\(\\beta\\-null recurrent process in presence of conditional heteroscedasticity. We show that the mean function estimator is consistent with convergence rate \\(\\sqrt{n(Th^{d}}\\, where \\(n(T\\ is the number of regenerations for a \\(\\beta\\-null recurrent process and the limiting distribution (with proper normalization is normal. Furthermore, we show that the two-step estimator for the volatility function is consistent. The finite sample performance of the estimate is quite reasonable when the leave-one-out cross validation method is used for bandwidth selection. We apply the proposed method to study the relationship of Federal funds rate with 3-month and 5-year T-bill rates and discover the existence of nonlinearity of the relationship. Furthermore, the in-sample and out-of-sample performance of the nonparametric model is far better than the linear model.

  17. Pair of null gravitating shells: III. Algebra of Dirac's observables

    International Nuclear Information System (INIS)

    Kouletsis, I; Hajicek, P

    2002-01-01

    The study of the two-shell system started in 'pair of null gravitating shells I and II' is continued. The pull back of the Liouville form to the constraint surface, which contains complete information about the Poisson brackets of Dirac observables, is computed in the singular double-null Eddington-Finkelstein (DNEF) gauge. The resulting formula shows that the variables conjugate to the Schwarzschild masses of the intershell spacetimes are simple combinations of the values of the DNEF coordinates on these spacetimes at the shells. The formula is valid for any number of in- and outgoing shells. After applying it to the two-shell system, the symplectic form is calculated for each component of the physical phase space; regular coordinates are found, defining it as a symplectic manifold. The symplectic transformation between the initial and final values of observables for the shell-crossing case is given

  18. Local modular Hamiltonians from the quantum null energy condition

    Science.gov (United States)

    Koeller, Jason; Leichenauer, Stefan; Levine, Adam; Shahbazi-Moghaddam, Arvin

    2018-03-01

    The vacuum modular Hamiltonian K of the Rindler wedge in any relativistic quantum field theory is given by the boost generator. Here we investigate the modular Hamiltonian for more general half-spaces which are bounded by an arbitrary smooth cut of a null plane. We derive a formula for the second derivative of the modular Hamiltonian with respect to the coordinates of the cut which schematically reads K''=Tv v . This formula can be integrated twice to obtain a simple expression for the modular Hamiltonian. The result naturally generalizes the standard expression for the Rindler modular Hamiltonian to this larger class of regions. Our primary assumptions are the quantum null energy condition—an inequality between the second derivative of the von Neumann entropy of a region and the stress tensor—and its saturation in the vacuum for these regions. We discuss the validity of these assumptions in free theories and holographic theories to all orders in 1 /N .

  19. Segmented Aperture Interferometric Nulling Testbed (SAINT) II: component systems update

    Science.gov (United States)

    Hicks, Brian A.; Bolcar, Matthew R.; Helmbrecht, Michael A.; Petrone, Peter; Burke, Elliot; Corsetti, James; Dillon, Thomas; Lea, Andrew; Pellicori, Samuel; Sheets, Teresa; Shiri, Ron; Agolli, Jack; DeVries, John; Eberhardt, Andrew; McCabe, Tyler

    2017-09-01

    This work presents updates to the coronagraph and telescope components of the Segmented Aperture Interferometric Nulling Testbed (SAINT). The project pairs an actively-controlled macro-scale segmented mirror with the Visible Nulling Coronagraph (VNC) towards demonstrating capabilities for the future space observatories needed to directly detect and characterize a significant sample of Earth-sized worlds around nearby stars in the quest for identifying those which may be habitable and possibly harbor life. Efforts to improve the VNC wavefront control optics and mechanisms towards repeating narrowband results are described. A narrative is provided for the design of new optical components aimed at enabling broadband performance. Initial work with the hardware and software interface for controlling the segmented telescope mirror is also presented.

  20. Lovelock vacua with a recurrent null vector field

    Czech Academy of Sciences Publication Activity Database

    Ortaggio, Marcello

    2018-01-01

    Roč. 97, č. 4 (2018), č. článku 044051. ISSN 2470-0010 R&D Projects: GA ČR GA13-10042S Institutional support: RVO:67985840 Keywords : Lovelock gravity * recurrent null vector field Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 4.568, year: 2016 https://journals.aps.org/prd/abstract/10.1103/PhysRevD.97.044051

  1. Spherical null geodesics of rotating Kerr black holes

    International Nuclear Information System (INIS)

    Hod, Shahar

    2013-01-01

    The non-equatorial spherical null geodesics of rotating Kerr black holes are studied analytically. Unlike the extensively studied equatorial circular orbits whose radii are known analytically, no closed-form formula exists in the literature for the radii of generic (non-equatorial) spherical geodesics. We provide here an approximate formula for the radii r ph (a/M;cosi) of these spherical null geodesics, where a/M is the dimensionless angular momentum of the black hole and cos i is an effective inclination angle (with respect to the black-hole equatorial plane) of the orbit. It is well-known that the equatorial circular geodesics of the Kerr spacetime (the prograde and the retrograde orbits with cosi=±1) are characterized by a monotonic dependence of their radii r ph (a/M;cosi=±1) on the dimensionless spin-parameter a/M of the black hole. We use here our novel analytical formula to reveal that this well-known property of the equatorial circular geodesics is actually not a generic property of the Kerr spacetime. In particular, we find that counter-rotating spherical null orbits in the range (3√(3)−√(59))/4≲cosi ph (a/M;cosi=const) on the dimensionless rotation-parameter a/M of the black hole. Furthermore, it is shown that spherical photon orbits of rapidly-rotating black holes are characterized by a critical inclination angle, cosi=√(4/7), above which the coordinate radii of the orbits approach the black-hole radius in the extremal limit. We prove that this critical inclination angle signals a transition in the physical properties of the spherical null geodesics: in particular, it separates orbits which are characterized by finite proper distances to the black-hole horizon from orbits which are characterized by infinite proper distances to the horizon.

  2. The quantum null energy condition in curved space

    Science.gov (United States)

    Fu, Zicao; Koeller, Jason; Marolf, Donald

    2017-11-01

    The quantum null energy condition (QNEC) is a conjectured bound on components (Tkk = Tab ka k^b) of the stress tensor along a null vector k a at a point p in terms of a second k-derivative of the von Neumann entropy S on one side of a null congruence N through p generated by k a . The conjecture has been established for super-renormalizeable field theories at points p that lie on a bifurcate Killing horizon with null tangent k a and for large-N holographic theories on flat space. While the Koeller-Leichenauer holographic argument clearly yields an inequality for general ( p, k^a) , more conditions are generally required for this inequality to be a useful QNEC. For d≤slant 3 , for arbitrary backgroud metric we show that the QNEC is naturally finite and independent of renormalization scheme when the expansion θ of N at the point p vanishes. This is consistent with the original QNEC conjecture which required θ and the shear σab to satisfy θ \\vert _p= \\dotθ\\vert p =0 , σab\\vert _p=0 . But for d=4, 5 more conditions than even these are required. In particular, we also require the vanishing of additional derivatives and a dominant energy condition. In the above cases the holographic argument does indeed yield a finite QNEC, though for d≥slant6 we argue these properties to fail even for weakly isolated horizons (where all derivatives of θ, σab vanish) that also satisfy a dominant energy condition. On the positive side, a corrollary to our work is that, when coupled to Einstein-Hilbert gravity, d ≤slant 3 holographic theories at large N satisfy the generalized second law (GSL) of thermodynamics at leading order in Newton’s constant G. This is the first GSL proof which does not require the quantum fields to be perturbations to a Killing horizon.

  3. Null half-supersymmetric solutions in five-dimensional supergravity

    International Nuclear Information System (INIS)

    Grover, Jai; Gutowski, Jan B.; Sabra, Wafic

    2008-01-01

    We classify half-supersymmetric solutions of gauged N = 2, D = 5 supergravity coupled to an arbitrary number of abelian vector multiplets for which all of the Killing spinors generate null Killing vectors. We show that there are four classes of solutions, and in each class we find the metric, scalars and gauge field strengths. When the scalar manifold is symmetric, the solutions correspond to a class of local near horizon geometries recently found by Kunduri and Lucietti.

  4. Yang-Mills theory in null path space

    International Nuclear Information System (INIS)

    Kent, S.L.

    1982-01-01

    A reformulation of classical GL(n,c) Yang-Mills theory is presented. The reformulation is in terms of a single matrix-valued function G on a six-dimensional subspace of the space of paths in Minkowski space, M. This subspace is defined as the null paths beginning at each point, (X/sup a/), of M and ending at future null infinity. A convenient parametrization of these paths is to give the Minkowski coordinates x/sup a/ of the starting point and the (complex) stereographic coordinates (xi, antixi) on S 2 which label the light cone generators of x/sup a/. A path is thus labeled by (x/sup a/,xi, antixi). The function G(x/sup a/,xi, antixi) is defined by the parallel propagation (with a given connection) of n linearly independent fiber vectors from x/sup a/ to null infinity along the (xi, antixi) generator. From knowledge of G(x/sup a/,xi, antixi) the connection one-form γ/sub a/ at the point x/sup a/ can be obtained is shown. Furthermore how the vacuum Yang-Mills equations can be imposed on the G is shown. This results in a rather complicated integro-differential equation for G which involves the characteristic initial data (essentially the radiation field) acting as the driving term. Two simple special cases are immediately obtainable; in the case of self-dual (or anti-self dual) fields the author obtains a simple derivation of the Sparling equation, namely delta G = -GA, while for Abelian (Maxwell) theories obtained the equation delta anti delta log G = -anti delta A-anti delta A, where A and its conjugate anti A are the characteristic free data given on null infinity. The latter equation is equivalent to the vacuum Maxwell equations

  5. Shearfree congruences of null geodesics and Killing tensors

    International Nuclear Information System (INIS)

    Dietz, W.; Ruediger, R.

    1980-01-01

    In this communication, the mutual connections between quantities that are generalizations of the notion of a a Killing vector field are investigated. A classification of these quantities in terms of a complex vector field αsub(a) is given. A common feature of all these quantities is that they imply the existence of a pair of shearfree geodetic null congruences. There are no explicit restrictions posed on the Ricci tensor. (author)

  6. Lovelock vacua with a recurrent null vector field

    Czech Academy of Sciences Publication Activity Database

    Ortaggio, Marcello

    2018-01-01

    Roč. 97, č. 4 (2018), č. článku 044051. ISSN 2470-0010 R&D Projects: GA ČR GA13-10042S Institutional support: RVO:67985840 Keywords : Lovelock gravity * recurrent null vector field Subject RIV: BA - General Mathematics OBOR OECD: Applied mathematics Impact factor: 4.568, year: 2016 https://journals. aps .org/prd/abstract/10.1103/PhysRevD.97.044051

  7. In Search of the Null: The NCSA 2003 Presidential Address

    Directory of Open Access Journals (Sweden)

    Beth Davison

    2003-10-01

    Full Text Available Sociologists usually publish articles where the results show statistically significant differences between two groups of people. Results which show the opposite are generally called 'negative findings,' and are not considered publishable. Davison argues that we really ought to be looking for and encouraging the null finding, especially when social inequality and poverty are the issue. In addition, society as a whole should be working to eliminate poverty and inequality

  8. Zero emission city. Preliminary study; Null-Emissions-Stadt. Sondierungsstudie

    Energy Technology Data Exchange (ETDEWEB)

    Diefenbach, N; Enseling, A; Werner, P; Flade, A; Greiff, R; Hennings, D; Muehlich, E; Wullkopf, U; Sturm, P; Kieslich, W; Born, R; Grossklos, M; Hatteh, R; Mueller, K; Ratschow, A; Valouch-Fornoff, C

    2002-10-01

    The idea of a 'zero emission city' is investigated by the Institut Wohnen und Umwelt on behalf of the Federal Minister of Education and Research. After describing the current situation and defining the key parameters of a 'zero emission city', settlement structures, power supply, production processes and transportation are analyzed and linked with the communal action level to obtain a framework for research, activities and actions. The study ends with recommendations for a research programme 'zero emission city'. (orig.) [German] Die von den Staedten der Industrielaender ausgehenden Emissionen stellen im Hinblick auf die globalen Belastungen wie z.B. Treibhauseffekt, Ozonabbau und Versauerung das Hauptproblem dar. Aus diesem Grunde bietet es sich an, den Gedanken der 'Null-Emissions-Stadt', der Vision einer moeglichst emissionsfreien Stadt, aufzugreifen und auf seine Tragfaehigkeit fuer innovative Handlungsmodelle forschungsstrategisch zu ueberpruefen. Das Bundesministerium fuer Bildung und Forschung hat das Institut Wohnen und Umwelt beauftragt, in einer Sondierungsstudie dieser Fragestellung nachzugehen. Nach der Festlegung der Ausgangsbedingungen und Eckpunkte der Vision 'Null-Emissions-Stadt' und der Analyse der vier Handlungsfelder Siedlungsstrukturen, Energieversorgung, Produktionsprozesse (Kreislaufwirtschaft) und Verkehr werden diese aufgegriffen und mit der kommunalen Handlungsebene verknuepft und zu einem Forschungs-, Handlungs- und moeglichen Aktionsrahmen zusammengefuegt. Die Studie schliesst mit Hinweisen fuer die Gestaltung eines Forschungsprogramms 'Null-Emissions-Stadt'. (orig.)

  9. The Quantum Focussing Conjecture and Quantum Null Energy Condition

    Science.gov (United States)

    Koeller, Jason

    Evidence has been gathering over the decades that spacetime and gravity are best understood as emergent phenomenon, especially in the context of a unified description of quantum mechanics and gravity. The Quantum Focussing Conjecture (QFC) and Quantum Null Energy Condition (QNEC) are two recently-proposed relationships between entropy and geometry, and energy and entropy, respectively, which further strengthen this idea. In this thesis, we study the QFC and the QNEC. We prove the QNEC in a variety of contexts, including free field theories on Killing horizons, holographic theories on Killing horizons, and in more general curved spacetimes. We also consider the implications of the QFC and QNEC in asymptotically flat space, where they constrain the information content of gravitational radiation arriving at null infinity, and in AdS/CFT, where they are related to other semiclassical inequalities and properties of boundary-anchored extremal area surfaces. It is shown that the assumption of validity and vacuum-state saturation of the QNEC for regions of flat space defined by smooth cuts of null planes implies a local formula for the modular Hamiltonian of these regions. We also demonstrate that the QFC as originally conjectured can be violated in generic theories in d ≥ 5, which led the way to an improved formulation subsequently suggested by Stefan Leichenauer.

  10. Zero emission city. Preliminary study; Null-Emissions-Stadt. Sondierungsstudie

    Energy Technology Data Exchange (ETDEWEB)

    Diefenbach, N.; Enseling, A.; Werner, P.; Flade, A.; Greiff, R.; Hennings, D.; Muehlich, E.; Wullkopf, U.; Sturm, P.; Kieslich, W.; Born, R.; Grossklos, M.; Hatteh, R.; Mueller, K.; Ratschow, A.; Valouch-Fornoff, C.

    2002-10-01

    The idea of a 'zero emission city' is investigated by the Institut Wohnen und Umwelt on behalf of the Federal Minister of Education and Research. After describing the current situation and defining the key parameters of a 'zero emission city', settlement structures, power supply, production processes and transportation are analyzed and linked with the communal action level to obtain a framework for research, activities and actions. The study ends with recommendations for a research programme 'zero emission city'. (orig.) [German] Die von den Staedten der Industrielaender ausgehenden Emissionen stellen im Hinblick auf die globalen Belastungen wie z.B. Treibhauseffekt, Ozonabbau und Versauerung das Hauptproblem dar. Aus diesem Grunde bietet es sich an, den Gedanken der 'Null-Emissions-Stadt', der Vision einer moeglichst emissionsfreien Stadt, aufzugreifen und auf seine Tragfaehigkeit fuer innovative Handlungsmodelle forschungsstrategisch zu ueberpruefen. Das Bundesministerium fuer Bildung und Forschung hat das Institut Wohnen und Umwelt beauftragt, in einer Sondierungsstudie dieser Fragestellung nachzugehen. Nach der Festlegung der Ausgangsbedingungen und Eckpunkte der Vision 'Null-Emissions-Stadt' und der Analyse der vier Handlungsfelder Siedlungsstrukturen, Energieversorgung, Produktionsprozesse (Kreislaufwirtschaft) und Verkehr werden diese aufgegriffen und mit der kommunalen Handlungsebene verknuepft und zu einem Forschungs-, Handlungs- und moeglichen Aktionsrahmen zusammengefuegt. Die Studie schliesst mit Hinweisen fuer die Gestaltung eines Forschungsprogramms 'Null-Emissions-Stadt'. (orig.)

  11. PERSEE: a nulling interferometer with dynamic correction of external perturbations

    Science.gov (United States)

    Jacquinod, S.; Houairi, K.; Le Duigou, J.-M.; Barillot, M.; Cassaing, F.; Réess, J.-M.; Hénault, F.; Sorrente, B.; Morinaud, G.; Amans, J.-P.; Coudé du Foresto, V.; Ollivier, M.

    2017-11-01

    Nulling interferometry is one of the direct detection methods assessed to find and characterize extrasolar planets and particularly telluric ones. Several projects such as Darwin [1;2], TPF-I [3;4], PEGASE [5;6] or FKSI [7], are currently considered. One of the main issues is the feasibility of a stable polychromatic null despite the presence of significant disturbances, induced by vibrations, atmospheric turbulence on the ground or satellite drift. Satisfying all these requirements is a great challenge and a key issue of these missions. In the context of the PEGASE mission, it was decided (in 2006), to build a laboratory demonstrator named PERSEE. It is the first laboratory setup which couples deep nulling interferometry with a free flying GNC simulator [8]. It is developed by a consortium composed of CNES, IAS, LESIA, OCA, ONERA, and TAS. In this paper, we detail the main objectives, the set-up and the function of the bench. We describe all the subsystems and we focus particularly on two key points of PERSEE: the beam combiner and the Fringe tracker.

  12. Kastor-Traschen black holes, null geodesics and conformal circles

    International Nuclear Information System (INIS)

    Casey, Stephen

    2012-01-01

    The Kastor-Traschen metric is a time-dependent solution of the Einstein-Maxwell equations with positive cosmological constant Λ which can be used to describe an arbitrary number of charged dynamical black holes. In this paper, we consider the null geodesic structure of this solution, in particular, focusing on the projection to the space of orbits of the timelike conformal retraction. It is found that these projected light rays arise as integral curves of a system of third-order ordinary differential equations. This system is not uniquely defined, however, and we use the inherent freedom to construct a new system whose integral curves coincide with the projection of distinguished null curves of Kastor-Traschen arising from a magnetic flow. We discuss our results in the one-centre case and demonstrate a link to conformal circles in the limit Λ → 0. We also show how to construct analytic expressions for the projected null geodesics of this metric by exploiting a well-known diffeomorphism between the K-T metric and extremal Reissner-Nordstrom-de Sitter. We make some remarks about the two-centre solution and demonstrate a link with the one-centre case. (paper)

  13. "Time sweet time": circadian characterization of galectin-1 null mice

    Directory of Open Access Journals (Sweden)

    Rabinovich Gabriel A

    2010-04-01

    Full Text Available Abstract Background Recent evidence suggests a two-way interaction between the immune and circadian systems. Circadian control of immune factors, as well as the effect of immunological variables on circadian rhythms, might be key elements in both physiological and pathological responses to the environment. Among these relevant factors, galectin-1 is a member of a family of evolutionarily-conserved glycan-binding proteins with both extracellular and intracellular effects, playing important roles in immune cell processes and inflammatory responses. Many of these actions have been studied through the use of mice with a null mutation in the galectin-1 (Lgals1 gene. To further analyze the role of endogenous galectin-1 in vivo, we aimed to characterize the circadian behavior of galectin-1 null (Lgals1-/- mice. Methods We analyzed wheel-running activity in light-dark conditions, constant darkness, phase responses to light pulses (LP at circadian time 15, and reentrainment to 6 hour shifts in light-dark schedule in wild-type (WT and Lgals1-/- mice. Results We found significant differences in free-running period, which was longer in mutant than in WT mice (24.02 vs 23.57 h, p alpha (14.88 vs. 12.35 circadian h, p Conclusions Given the effect of a null mutation on circadian period and entrainment, we indicate that galectin-1 could be involved in the regulation of murine circadian rhythmicity. This is the first study implicating galectin-1 in the mammalian circadian system.

  14. The Proatherogenic Effect of Chronic Nitric Oxide Synthesis Inhibition in ApoE-Null Mice Is Dependent on the Presence of PPARα

    Directory of Open Access Journals (Sweden)

    Michal Vechoropoulos

    2014-01-01

    Full Text Available Inhibition of endothelial nitric oxide synthase (eNOS accelerates atherosclerosis in ApoE-null mice by impairing the balance between angiotensin II (AII and NO. Our previous data suggested a role for PPARα in the deleterious effect of the renin-angiotensin system (RAS. We tested the hypothesis that ApoE-null mice lacking PPARα (DKO mice would be resistant to the proatherogenic effect of NOS inhibition. DKO mice fed a Western diet were immune to the 23% worsening in aortic sinus plaque area seen in the ApoE-null animals under 12 weeks of NOS inhibition with a subpressor dose of L-NAME, P=0.002. This was accompanied by a doubling of reactive oxygen species (ROS- generating aortic NADPH oxidase activity (a target of AII, which paralleled Nox1 expression and by a 10-fold excess of the proatherogenic iNOS, P<0.01. L-NAME also caused a doubling of aortic renin and angiotensinogen mRNA level in the ApoE-null mice but not in the DKO, and it upregulated eNOS in the DKO mice only. These data suggest that, in the ApoE-null mouse, PPARα contributes to the proatherogenic effect of unopposed RAS/AII action induced by L-NAME, an effect which is associated with Nox1 and iNOS induction, and is independent of blood pressure and serum lipids.

  15. Variational principle for gravity with null and non-null boundaries: a unified boundary counter-term

    Energy Technology Data Exchange (ETDEWEB)

    Parattu, Krishnamohan; Chakraborty, Sumanta; Padmanabhan, T. [IUCAA, Post Bag 4, Pune (India)

    2016-03-15

    It is common knowledge that the Einstein-Hilbert action does not furnish a well-posed variational principle. The usual solution to this problem is to add an extra boundary term to the action, called a counter-term, so that the variational principle becomes well-posed. When the boundary is spacelike or timelike, the Gibbons-Hawking-York counter-term is the most widely used. For null boundaries, we had proposed a counter-term in a previous paper. In this paper, we extend the previous analysis and propose a counter-term that can be used to eliminate variations of the ''off-the-surface'' derivatives of the metric on any boundary, regardless of its spacelike, timelike or null nature. (orig.)

  16. Left cardiac isomerism in the Sonic hedgehog null mouse.

    Science.gov (United States)

    Hildreth, Victoria; Webb, Sandra; Chaudhry, Bill; Peat, Jonathan D; Phillips, Helen M; Brown, Nigel; Anderson, Robert H; Henderson, Deborah J

    2009-06-01

    Sonic hedgehog (Shh) is a secreted morphogen necessary for the production of sidedness in the developing embryo. In this study, we describe the morphology of the atrial chambers and atrioventricular junctions of the Shh null mouse heart. We demonstrate that the essential phenotypic feature is isomerism of the left atrial appendages, in combination with an atrioventricular septal defect and a common atrioventricular junction. These malformations are known to be frequent in humans with left isomerism. To confirm the presence of left isomerism, we show that Pitx2c, a recognized determinant of morphological leftness, is expressed in the Shh null mutants on both the right and left sides of the inflow region, and on both sides of the solitary arterial trunk exiting from the heart. It has been established that derivatives of the second heart field expressing Isl1 are asymmetrically distributed in the developing normal heart. We now show that this population is reduced in the hearts from the Shh null mutants, likely contributing to the defects. To distinguish the consequences of reduced contributions from the second heart field from those of left-right patterning disturbance, we disrupted the movement of second heart field cells into the heart by expressing dominant-negative Rho kinase in the population of cells expressing Isl1. This resulted in absence of the vestibular spine, and presence of atrioventricular septal defects closely resembling those seen in the hearts from the Shh null mutants. The primary atrial septum, however, was well formed, and there was no evidence of isomerism of the atrial appendages, suggesting that these features do not relate to disruption of the contributions made by the second heart field. We demonstrate, therefore, that the Shh null mouse is a model of isomerism of the left atrial appendages, and show that the recognized associated malformations found at the venous pole of the heart in the setting of left isomerism are likely to arise from

  17. Polymorphism of proteins in selected slovak winter wheat genotypes using SDS-PAGE

    Directory of Open Access Journals (Sweden)

    Dana Miháliková

    2016-12-01

    Full Text Available Winter wheat is especially used for bread-making. The specific composition of the grain storage proteins and the representation of individual subunits determines the baking quality of wheat. The aim of this study was to analyze 15 slovak varieties of the winter wheat (Triticum aestivum L. based on protein polymorphism and to predict their technological quality. SDS-PAGE method by ISTA was used to separate glutenin protein subunits. Glutenins were separated into HMW-GS (15.13% and LMW-GS (65.89% on the basis of molecular weight in SDS-PAGE. At the locus Glu-A1 was found allele Null (53% of genotypes and allele 1 (47% of genotypes. The locus Glu-B1 was represented by the HMW-GS subunits 6+8 (33% of genotypes, 7+8 (27% of genotypes, 7+9 (40% of genotypes. At the locus Glu-D1 were detected two subunits, 2+12 (33% of genotypes and 5+10 (67% of genotypes which is correlated with good bread-making properties. The Glu – score was ranged from 4 (genotype Viglanka to 10 (genotypes Viola, Vladarka. According to the representation of individual glutenin subunits in samples, the dendrogram of genetic similarity was constructed. By the prediction of quality the results showed that the best technological quality was significant in the varieties Viola and Vladarka which are suitable for use in food processing.

  18. Sucrose fermentation by Saccharomyces cerevisiae lacking hexose transport.

    Science.gov (United States)

    Batista, Anderson S; Miletti, Luiz C; Stambuk, Boris U

    2004-01-01

    Sucrose is the major carbon source used by Saccharomyces cerevisiae during production of baker's yeast, fuel ethanol and several distilled beverages. It is generally accepted that sucrose fermentation proceeds through extracellular hydrolysis of the sugar, mediated by the periplasmic invertase, producing glucose and fructose that are transported into the cells and metabolized. In the present work we analyzed the contribution to sucrose fermentation of a poorly characterized pathway of sucrose utilization by S. cerevisiae cells, the active transport of the sugar through the plasma membrane and its intracellular hydrolysis. A yeast strain that lacks the major hexose transporters (hxt1-hxt7 and gal2) is incapable of growing on or fermenting glucose or fructose. Our results show that this hxt-null strain is still able to ferment sucrose due to direct uptake of the sugar into the cells. Deletion of the AGT1 gene, which encodes a high-affinity sucrose-H(+) symporter, rendered cells incapable of sucrose fermentation. Since sucrose is not an inducer of the permease, expression of the AGT1 must be constitutive in order to allow growth of the hxt-null strain on sucrose. The molecular characterization of active sucrose transport and fermentation by S. cerevisiae cells opens new opportunities to optimize yeasts for sugarcane-based industrial processes.

  19. Juvenile manifestation of ultrasound communication deficits in the neuroligin-4 null mutant mouse model of autism.

    Science.gov (United States)

    Ju, Anes; Hammerschmidt, Kurt; Tantra, Martesa; Krueger, Dilja; Brose, Nils; Ehrenreich, Hannelore

    2014-08-15

    Neuroligin-4 (Nlgn4) is a member of the neuroligin family of postsynaptic cell adhesion molecules. Loss-of-function mutations of NLGN4 are among the most frequent, known genetic causes of heritable autism. Adult Nlgn4 null mutant (Nlgn4(-/-)) mice are a construct valid model of human autism, with both genders displaying a remarkable autistic phenotype, including deficits in social interaction and communication as well as restricted and repetitive behaviors. In contrast to adults, autism-related abnormalities in neonatal and juvenile Nlgn4(-/-) mice have not been reported yet. The present study has been designed to systematically investigate in male and female Nlgn4(-/-) pups versus wildtype littermates (WT, Nlgn4(+/+)) developmental milestones and stimulus-induced ultrasound vocalization (USV). Neonatal development, followed daily from postnatal days (PND) 4 to 21, including physical development, neurological reflexes and neuromotor coordination, did not yield any differences between Nlgn4(-/-) and their WT littermates. USV in pups (PND8-9) in response to brief separation from their mothers revealed remarkable gender effects, and a genotype influence in females regarding latency to first call. In juveniles (PND22-23), USV monitoring upon exposure to an anesthetized female intruder mouse uncovered a clear genotype effect with reduced USV in Nlgn4(-/-) mice, and again a more prominent phenotype in females. Together, these data support an early manifestation of communication deficits in Nlgn4(-/-) mice that appear more pronounced in immature females with their overall stronger USV as compared to males. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Impaired intestinal proglucagon processing in mice lacking prohormone convertase 1

    DEFF Research Database (Denmark)

    Ugleholdt, Randi; Zhu, Xiaorong; Deacon, Carolyn F

    2003-01-01

    proglucagon processing showed marked defects. Tissue proglucagon levels in null mice were elevated, and proglucagon processing to glicentin, oxyntomodulin, and glucagon-like peptide-1 and -2 (GLP-1 and GLP-2) was markedly decreased, indicating that PC1 is essential for the processing of all the intestinal...... proglucagon cleavage sites. This includes the monobasic site R(77) and, thereby, production of mature, biologically active GLP-1. We also found elevated glucagon levels, suggesting that factors other than PC1 that are capable of processing to mature glucagon are present in the secretory granules of the L cell......The neuroendocrine prohormone convertases 1 and 2 (PC1 and PC2) are expressed in endocrine intestinal L cells and pancreatic A cells, respectively, and colocalize with proglucagon in secretory granules. Mice lacking PC2 have multiple endocrinopathies and cannot process proglucagon to mature...

  1. Vacuum Nuller Testbed Performance, Characterization and Null Control

    Science.gov (United States)

    Lyon, R. G.; Clampin, M.; Petrone, P.; Mallik, U.; Madison, T.; Bolcar, M.; Noecker, C.; Kendrick, S.; Helmbrecht, M. A.

    2011-01-01

    The Visible Nulling Coronagraph (VNC) can detect and characterize exoplanets with filled, segmented and sparse aperture telescopes, thereby spanning the choice of future internal coronagraph exoplanet missions. NASA/Goddard Space Flight Center (GSFC) has developed a Vacuum Nuller Testbed (VNT) to advance this approach, and assess and advance technologies needed to realize a VNC as a flight instrument. The VNT is an ultra-stable testbed operating at 15 Hz in vacuum. It consists of a MachZehnder nulling interferometer; modified with a "W" configuration to accommodate a hexpacked MEMS based deformable mirror (DM), coherent fiber bundle and achromatic phase shifters. The 2-output channels are imaged with a vacuum photon counting camera and conventional camera. Error-sensing and feedback to DM and delay line with control algorithms are implemented in a real-time architecture. The inherent advantage of the VNC is that it is its own interferometer and directly controls its errors by exploiting images from bright and dark channels simultaneously. Conservation of energy requires the sum total of the photon counts be conserved independent of the VNC state. Thus sensing and control bandwidth is limited by the target stars throughput, with the net effect that the higher bandwidth offloads stressing stability tolerances within the telescope. We report our recent progress with the VNT towards achieving an incremental sequence of contrast milestones of 10(exp 8) , 10(exp 9) and 10(exp 10) respectively at inner working angles approaching 2A/D. Discussed will be the optics, lab results, technologies, and null control. Shown will be evidence that the milestones have been achieved.

  2. A visualization of null geodesics for the bonnor massive dipole

    Directory of Open Access Journals (Sweden)

    G. Andree Oliva Mercado

    2015-08-01

    Full Text Available In this work we simulate null geodesics for the Bonnor massive dipole metric by implementing a symbolic-numerical algorithm in Sage and Python. This program is also capable of visualizing in 3D, in principle, the geodesics for any given metric. Geodesics are launched from a common point, collectively forming a cone of light beams, simulating a solid-angle section of a point source in front of a massive object with a magnetic field. Parallel light beams also were considered, and their bending due to the curvature of the space-time was simulated.

  3. Do electromagnetic waves always propagate along null geodesics?

    International Nuclear Information System (INIS)

    Asenjo, Felipe A; Hojman, Sergio A

    2017-01-01

    We find exact solutions to Maxwell equations written in terms of four-vector potentials in non–rotating, as well as in Gödel and Kerr spacetimes. We show that Maxwell equations can be reduced to two uncoupled second-order differential equations for combinations of the components of the four-vector potential. Exact electromagnetic waves solutions are written on given gravitational field backgrounds where they evolve. We find that in non–rotating spherical symmetric spacetimes, electromagnetic waves travel along null geodesics. However, electromagnetic waves on Gödel and Kerr spacetimes do not exhibit that behavior. (paper)

  4. Two-loop string theory on null compactifications

    International Nuclear Information System (INIS)

    Cove, Henry C.D.; Szabo, Richard J.

    2006-01-01

    We compute the two-loop contributions to the free energy in the null compactification of perturbative string theory at finite temperature. The cases of bosonic, type II and heterotic strings are all treated. The calculation exploits an explicit reductive parametrization of the moduli space of infinite-momentum frame string worldsheets in terms of branched cover instantons. Various arithmetic and physical properties of the instanton sums are described. Applications to symmetric product orbifold conformal field theories and to the matrix string theory conjecture are also briefly discussed

  5. Twisting null geodesic congruences and the Einstein-Maxwell equations

    International Nuclear Information System (INIS)

    Newman, Ezra T; Silva-Ortigoza, Gilberto

    2006-01-01

    In a recent article, we returned to the study of asymptotically flat solutions of the vacuum Einstein equations with a rather unconventional point of view. The essential observation in that work was that from a given asymptotically flat vacuum spacetime with a given Bondi shear, one can find a class of asymptotically shear-free (but, in general, twisting) null geodesic congruences where the class was uniquely given up to the arbitrary choice of a complex analytic 'worldline' in a four-dimensional complex space. By imitating certain terms in the Weyl tensor that are found in the algebraically special type II metrics, this complex worldline could be made unique and given-or assigned-the physical meaning as the complex centre of mass. Equations of motion for this case were found. The purpose of the present work is to extend those results to asymptotically flat solutions of the Einstein-Maxwell equations. Once again, in this case, we get a class of asymptotically shear-free null geodesic congruences depending on a complex worldline in the same four-dimensional complex space. However in this case there will be, in general, two distinct but uniquely chosen worldlines, one of which can be assigned as the complex centre of charge while the other could be called the complex centre of mass. Rather than investigating the situation where there are two distinct complex worldlines, we study instead the special degenerate case where the two worldlines coincide, i.e., where there is a single unique worldline. This mimics the case of algebraically special Einstein-Maxwell fields where the degenerate principle null vector of the Weyl tensor coincides with a Maxwell principle null vector. Again we obtain equations of motion for this worldline-but explicitly found here only in an approximation. Though there are ambiguities in assigning physical meaning to different terms it appears as if reliance on the Kerr and charged Kerr metrics and classical electromagnetic radiation theory helps

  6. The null-event method in computer simulation

    International Nuclear Information System (INIS)

    Lin, S.L.

    1978-01-01

    The simulation of collisions of ions moving under the influence of an external field through a neutral gas to non-zero temperatures is discussed as an example of computer models of processes in which a probe particle undergoes a series of interactions with an ensemble of other particles, such that the frequency and outcome of the events depends on internal properties of the second particles. The introduction of null events removes the need for much complicated algebra, leads to a more efficient simulation and reduces the likelihood of logical error. (Auth.)

  7. Null geodesic deviation II. Conformally flat space--times

    International Nuclear Information System (INIS)

    Peters, P.C.

    1975-01-01

    The equation of geodesic deviation is solved in conformally flat space--time in a covariant manner. The solution is given as an integral equation for general geodesics. The solution is then used to evaluate second derivatives of the world function and derivatives of the parallel propagator, which need to be known in order to find the Green's function for wave equations in curved space--time. A method of null geodesic limits of two-point functions is discussed, and used to find the scalar Green's function as an iterative series

  8. Empirical Statistical Power for Testing Multilocus Genotypic Effects under Unbalanced Designs Using a Gibbs Sampler

    Directory of Open Access Journals (Sweden)

    Chaeyoung Lee

    2012-11-01

    Full Text Available Epistasis that may explain a large portion of the phenotypic variation for complex economic traits of animals has been ignored in many genetic association studies. A Baysian method was introduced to draw inferences about multilocus genotypic effects based on their marginal posterior distributions by a Gibbs sampler. A simulation study was conducted to provide statistical powers under various unbalanced designs by using this method. Data were simulated by combined designs of number of loci, within genotype variance, and sample size in unbalanced designs with or without null combined genotype cells. Mean empirical statistical power was estimated for testing posterior mean estimate of combined genotype effect. A practical example for obtaining empirical statistical power estimates with a given sample size was provided under unbalanced designs. The empirical statistical powers would be useful for determining an optimal design when interactive associations of multiple loci with complex phenotypes were examined.

  9. The new null testing method for the special optical window

    Science.gov (United States)

    Huang, Changchun

    2009-07-01

    The high speed, high precision and wide range specifications are requirement for the modern aircraft, which the traditional hemispherical dome can't achieve now, and the novel conformal window instead can enhance the aerodynamic performance of the aircraft obviously. To reduce the aerodynamic drag and radar cross-section, the window geometry is generally aspheric in shape. As a result, the involved fabrication and testing processes are much more challenging than that of conventional optics and must be mastered before these windows and systems can be implemented at an acceptable cost and risk. Metrology is one of the critical areas required to advance the conformal window technology. But as the surface of these conformal windows is not the traditional sphere lens, the measurement method for it is infeasible with the conventional optics measurement processes. This paper we express the development of testing technology for the special conformal windows in brief, and emphatically introduces one available novel testing method- a new null testing, and here based on the theory of compensation methods, The principle of Offner's refractive null lens has been extended to test the transmission wavefront through conformal window optics and provide feedback during surface fabrication. a compensator system for the was designed for the conformal window is given which parameters are 100mm for its aperture and two parabolic surface as conformal window, the final residual wavefront error(RMS) of which is less than 1/20λ(λ=632.8nm).

  10. Pituitary null cell adenoma in a domestic llama (Lama glama).

    Science.gov (United States)

    Chalkley, M D; Kiupel, M; Draper, A C E

    2014-07-01

    Pituitary gland neoplasia has been reported rarely in camelids. A 12-year-old neutered male llama (Lama glama) presented with lethargy, inappetence and neurological signs. On physical examination, the llama was mentally dull and exhibited compulsive pacing and circling to the left. Complete blood count and serum biochemistry revealed haemoconcentration, mild hypophosphataemia, hyperglycaemia, hypercreatininaemia and hyperalbuminaemia. Humane destruction was elected due to rapid clinical deterioration and poor prognosis. Post-mortem examination revealed a pituitary macroadenoma and bilateral internal hydrocephalus. Microscopically, the pituitary tumour was composed of neoplastic chromophobic pituitary cells. Ultrastructural studies revealed similar neoplastic cells to those previously described in human null cell adenomas. Immunohistochemically, the neoplastic cells were strongly immunoreactive for neuroendocrine markers (synaptophysin and chromogranin A), but did not exhibit immunoreactivity for epithelial, mesenchymal, neuronal and all major pituitary hormone markers (adrenocorticotropic hormone, follicle stimulating hormone, growth hormone, luteinizing hormone, melanocyte-stimulating hormone, prolactin and thyroid stimulating hormone), consistent with the diagnosis of a pituitary null cell adenoma. This is the first report of pituitary neoplasia in a llama. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Randomizing growing networks with a time-respecting null model

    Science.gov (United States)

    Ren, Zhuo-Ming; Mariani, Manuel Sebastian; Zhang, Yi-Cheng; Medo, Matúš

    2018-05-01

    Complex networks are often used to represent systems that are not static but grow with time: People make new friendships, new papers are published and refer to the existing ones, and so forth. To assess the statistical significance of measurements made on such networks, we propose a randomization methodology—a time-respecting null model—that preserves both the network's degree sequence and the time evolution of individual nodes' degree values. By preserving the temporal linking patterns of the analyzed system, the proposed model is able to factor out the effect of the system's temporal patterns on its structure. We apply the model to the citation network of Physical Review scholarly papers and the citation network of US movies. The model reveals that the two data sets are strikingly different with respect to their degree-degree correlations, and we discuss the important implications of this finding on the information provided by paradigmatic node centrality metrics such as indegree and Google's PageRank. The randomization methodology proposed here can be used to assess the significance of any structural property in growing networks, which could bring new insights into the problems where null models play a critical role, such as the detection of communities and network motifs.

  12. Geometry of extended null supersymmetry in M theory

    International Nuclear Information System (INIS)

    Conamhna, Oisin A.P. Mac

    2006-01-01

    For supersymmetric spacetimes in 11 dimensions admitting a null Killing spinor, a set of explicit necessary and sufficient conditions for the existence of any number of arbitrary additional Killing spinors is derived. The necessary and sufficient conditions are comprised of algebraic relationships, linear in the spinorial components, between the spinorial components and their first derivatives, and the components of the spin connection and four-form. The integrability conditions for the Killing spinor equation are also analyzed in detail, to determine which components of the field equations are implied by arbitrary additional supersymmetries and the four-form Bianchi identity. This provides a complete formalism for the systematic and exhaustive investigation of all spacetimes with extended null supersymmetry in 11 dimensions. The formalism is employed to show that the general bosonic solution of 11 dimensional supergravity admitting a G 2 structure defined by four Killing spinors is either locally the direct product of R 1,3 with a seven-manifold of G 2 holonomy, or locally the Freund-Rubin direct product of AdS 4 with a seven-manifold of weak G 2 holonomy. In addition, all supersymmetric spacetimes admitting a (G 2 xR 7 )xR 2 structure are classified

  13. Extrasolar Planetary Imaging Coronagraph (EPIC): visible nulling cornagraph testbed results

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Melnick, Gary; Tolls, Volker; Woodruff, Robert; Vasudevan, Gopal

    2008-07-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a NASA Astrophysics Strategic Mission Concept under study for the upcoming Exoplanet Probe. EPIC's mission would be to image and characterize extrasolar giant planets, and potential super-Earths, in orbits with semi-major axes between 2 and 10 AU. EPIC will provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys and potentially some transits, determine orbital inclinations and masses, characterize the atmospheres of gas giants around A and F stars, observed the inner spatial structure and colors of inner Spitzer selected debris disks. EPIC would be launched into a heliocentric Earth trailing drift-away orbit, with a 3-year mission lifetime (5 year goal) and will revisit planets at least three times. The starlight suppression approach consists of a visible nulling coronagraph (VNC) that enables high order starlight suppression in broadband light. To demonstrate the VNC approach and advance it's technology readiness the NASA/Goddard Space Flight Center and Lockheed-Martin have developed a laboratory VNC and have demonstrated white light nulling. We will discuss our ongoing VNC work and show the latest results from the VNC testbed.

  14. Extrasolar Planetary Imaging Coronagraph: Visible Nulling Coronagraph Testbed Results

    Science.gov (United States)

    Lyon, Richard G.

    2008-01-01

    The Extrasolar Planetary Imaging Coronagraph (EPIC) is a proposed NASA Discovery mission to image and characterize extrasolar giant planets in orbits with semi-major axes between 2 and 10 AU. EPIC will provide insights into the physical nature of a variety of planets in other solar systems complimenting radial velocity (RV) and astrometric planet searches. It will detect and characterize the atmospheres of planets identified by radial velocity surveys, determine orbital inclinations and masses, characterize the atmospheres around A and F stars, observed the inner spatial structure and colors of inner Spitzer selected debris disks. EPIC would be launched to heliocentric Earth trailing drift-away orbit, with a 3-year mission lifetime ( 5 year goal) and will revisit planets at least three times at intervals of 9 months. The starlight suppression approach consists of a visible nulling coronagraph (VNC) that enables high order starlight suppression in broadband light. To demonstrate the VNC approach and advance it's technology readiness the NASA Goddard Space Flight Center and Lockheed-Martin have developed a laboratory VNC and have demonstrated white light nulling. We will discuss our ongoing VNC work and show the latest results from the VNC testbed,

  15. Non-dissipative electromagnetic media with two Lorentz null cones

    International Nuclear Information System (INIS)

    Dahl, Matias F.

    2013-01-01

    We study Maxwell’s equations on a 4-manifold where the electromagnetic medium is modeled by an antisymmetric (2/2 )-tensor with 21 real coefficients. In this setting the Fresnel surface is a fourth-order polynomial surface that describes the dynamical response of the medium in the geometric optics limit. For example, in an isotropic medium the Fresnel surface is a Lorentz null cone. The contribution of this paper is the pointwise description of all electromagnetic medium tensors κ with real coefficients that satisfy the following three conditions: (i)medium κ is invertible, (ii)medium κ is skewon-free, or non-dissipative, (iii)the Fresnel surface of κ is the union of two distinct Lorentz null cones. We show that there are only three classes of media with these properties and give explicit expressions in local coordinates for each class. - Highlights: ► We find two new electromagnetic media classes for which the Fresnel surface decomposes into two light cones. ► In a suitable setting we classify all electromagnetic media where this is the case. ► We find an electromagnetic medium tensor with three different signal speeds in one direction. ► The work is related to [5], which classifies all media with one light cone (in a suitable setting).

  16. Plate with a hole obeys the averaged null energy condition

    International Nuclear Information System (INIS)

    Graham, Noah; Olum, Ken D.

    2005-01-01

    The negative energy density of Casimir systems appears to violate general relativity energy conditions. However, one cannot test the averaged null energy condition (ANEC) using standard calculations for perfectly reflecting plates, because the null geodesic would have to pass through the plates, where the calculation breaks down. To avoid this problem, we compute the contribution to ANEC for a geodesic that passes through a hole in a single plate. We consider both Dirichlet and Neumann boundary conditions in two and three space dimensions. We use a Babinet's principle argument to reduce the problem to a complementary finite disk correction to the perfect mirror result, which we then compute using scattering theory in elliptical and spheroidal coordinates. In the Dirichlet case, we find that the positive correction due to the hole overwhelms the negative contribution of the infinite plate. In the Neumann case, where the infinite plate gives a positive contribution, the hole contribution is smaller in magnitude, so again ANEC is obeyed. These results can be extended to the case of two plates in the limits of large and small hole radii. This system thus provides another example of a situation where ANEC turns out to be obeyed when one might expect it to be violated

  17. Nutritional intervention restores muscle but not kidney phenotypes in adult calcineurin Aα null mice.

    Directory of Open Access Journals (Sweden)

    Kirsten Madsen

    Full Text Available Mice lacking the α isoform of the catalytic subunit of calcineurin (CnAα were first reported in 1996 and have been an important model to understand the role of calcineurin in the brain, immune system, bones, muscle, and kidney. Research using the mice has been limited, however, by failure to thrive and early lethality of most null pups. Work in our laboratory led to the rescue of CnAα-/- mice by supplemental feeding to compensate for a defect in salivary enzyme secretion. The data revealed that, without intervention, knockout mice suffer from severe caloric restriction. Since nutritional deprivation is known to significantly alter development, it is imperative that previous conclusions based on CnAα-/- mice are revisited to determine which aspects of the phenotype were attributable to caloric restriction versus a direct role for CnAα. In this study, we find that defects in renal development and function persist in adult CnAα-/- mice including a significant decrease in glomerular filtration rate and an increase in blood urea nitrogen levels. These data indicate that impaired renal development we previously reported was not due to caloric restriction but rather a specific role for CnAα in renal development and function. In contrast, we find that rather than being hypoglycemic, rescued mice are mildly hyperglycemic and insulin resistant. Examination of muscle fiber types shows that previously reported reductions in type I muscle fibers are no longer evident in rescued null mice. Rather, loss of CnAα likely alters insulin response due to a reduction in insulin receptor substrate-2 (IRS2 expression and signaling in muscle. This study illustrates the importance of re-examining the phenotypes of CnAα-/- mice and the advances that are now possible with the use of adult, rescued knockout animals.

  18. Evidence for complete epistasis of null mutations in murine Fanconi anemia genes Fanca and Fancg.

    Science.gov (United States)

    van de Vrugt, Henri J; Koomen, Mireille; Bakker, Sietske; Berns, Mariska A D; Cheng, Ngan Ching; van der Valk, Martin A; de Vries, Yne; Rooimans, Martin A; Oostra, Anneke B; Hoatlin, Maureen E; Te Riele, Hein; Joenje, Hans; Arwert, Fré

    2011-12-10

    Fanconi anemia (FA) is a heritable disease characterized by bone marrow failure, congenital abnormalities, and cancer predisposition. The 15 identified FA genes operate in a molecular pathway to preserve genomic integrity. Within this pathway the FA core complex operates as an ubiquitin ligase that activates the complex of FANCD2 and FANCI to coordinate DNA repair. The FA core complex is formed by at least 12 proteins. However, only the FANCL subunit displays ubiquitin ligase activity. FANCA and FANCG are members of the FA core complex for which no other functions have been described than to participate in protein interactions. In this study we generated mice with combined null alleles for Fanca and Fancg to identify extended functions for these genes by characterizing the double mutant mice and cells. Double mutant a(-/-)/g(-/-) mice were born at near Mendelian frequencies without apparent developmental abnormalities. Histological analysis of a(-/-)/g(-/-) mice revealed a Leydig cell hyperplasia and frequent vacuolization of Sertoli cells in testes, while ovaries were depleted from developing follicles and displayed an interstitial cell hyperplasia. These gonadal aberrations were associated with a compromised fertility of a(-/-)/g(-/-) males and females. During the first year of life a(-/-)/g(-/-) did not develop malignancies or bone marrow failure. At the cellular level a(-/-)/g(-/-), Fanca(-/-), and Fancg(-/-) cells proved equally compromised in DNA crosslink and homology-directed repair. Overall the phenotype of a(-/-)/g(-/-) double knockout mice and cells appeared highly similar to the phenotype of Fanca or Fancg single knockouts. The lack of an augmented phenotype suggest that null mutations in Fanca or Fancg are fully epistatic, making additional important functions outside of the FA core complex highly unlikely. 2011 Elsevier B.V. All rights reserved.

  19. Impairment of Infectivity and Immunoprotective Effect of a LYT1 Null Mutant of Trypanosoma cruzi▿

    Science.gov (United States)

    Zago, M. Paola; Barrio, Alejandra B.; Cardozo, Rubén M.; Duffy, Tomás; Schijman, Alejandro G.; Basombrío, Miguel A.

    2008-01-01

    Trypanosoma cruzi infection of host cells is a complex process in which many proteins participate but only a few of these proteins have been identified experimentally. One parasite factor likely to be involved is the protein product of LYT1, a single-copy gene cloned, sequenced, and characterized by Manning-Cela et al. (Infect. Immun. 69:3916-3923, 2001). This gene was potentially associated with infectivity, since the deletion of both LYT1 alleles in the CL Brenner strain (the wild type [WT]) resulted in a null mutant T. cruzi clone (L16) that shows an attenuated phenotype in cell culture models. The aim of this work was to characterize the infective behavior of L16 in the insect vector and murine models. The infection of adult Swiss mice with 103 trypomastigotes of both clones revealed a significant reduction in infective behavior of L16, as shown by direct parasitemia, spleen index, and quantitation of tissue parasite burden, suggesting the loss of virulence in the null mutant clone. Although L16 blood counts were almost undetectable, blood-based PCRs indicated the presence of latent and persistent infection during all of the study period and epimastigotes were reisolated from hemocultures until 12 months postinfection. Nevertheless, virulence was not restored in L16 by serial passages in mice, and reisolated parasites lacking the LYT1 gene and bearing the antibiotic resistance genes revealed the stability of the genetic manipulation. Histopathological studies showed a strong diminution in the muscle inflammatory response triggered by L16 compared to that triggered by the WT group, consistent with a lower tissue parasite load. A strong protection against a virulent challenge in both L16- and WT-infected mice was observed; however, the immunizing infection by the genetically modified parasite was highly attenuated. PMID:17938222

  20. Meterwavelength Single-pulse Polarimetric Emission Survey. III. The Phenomenon of Nulling in Pulsars

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Rahul; Mitra, Dipanjan; Melikidze, George I., E-mail: rahulbasu.astro@gmail.com [Janusz Gil Institute of Astronomy, University of Zielona Góra, ul. Szafrana 2, 65–516 Zielona Góra (Poland)

    2017-09-10

    A detailed analysis of nulling was conducted for the pulsars studied in the Meterwavelength Single-pulse Polarimetric Emission Survey. We characterized nulling in 36 pulsars including 17 pulsars where the phenomenon was reported for the first time. The most dominant nulls lasted for a short duration, less than five periods. Longer duration nulls extending to hundreds of periods were also seen in some cases. A careful analysis showed the presence of periodicities in the transition from the null to the burst states in 11 pulsars. In our earlier work, fluctuation spectrum analysis showed multiple periodicities in 6 of these 11 pulsars. We demonstrate that the longer periodicity in each case was associated with nulling. The shorter periodicities usually originate from subpulse drifting. The nulling periodicities were more aligned with the periodic amplitude modulation, indicating a possible common origin for both. The most prevalent nulls last for a single period and can be potentially explained using random variations affecting the plasma processes in the pulsar magnetosphere. On the other hand, longer-duration nulls require changes in the pair-production processes, which need an external triggering mechanism for the changes. The presence of periodic nulling puts an added constraint on the triggering mechanism, which also needs to be periodic.

  1. Mice null for the deubiquitinase USP18 spontaneously develop leiomyosarcomas

    International Nuclear Information System (INIS)

    Chinyengetere, Fadzai; Sekula, David J.; Lu, Yun; Giustini, Andrew J.; Sanglikar, Aarti; Kawakami, Masanori; Ma, Tian; Burkett, Sandra S.; Eisenberg, Burton L.; Wells, Wendy A.; Hoopes, Paul J.; Demicco, Elizabeth G.; Lazar, Alexander J; Torres, Keila E.; Memoli, Vincent; Freemantle, Sarah J.; Dmitrovsky, Ethan

    2015-01-01

    USP18 (ubiquitin-specific protease 18) removes ubiquitin-like modifier interferon stimulated gene 15 (ISG15) from conjugated proteins. USP18 null mice in a FVB/N background develop tumors as early as 2 months of age. These tumors are leiomyosarcomas and thus represent a new murine model for this disease. Heterozygous USP18 +/− FVB/N mice were bred to generate wild-type, heterozygous and homozygous cohorts. Tumors were characterized immunohistochemically and two cell lines were derived from independent tumors. Cell lines were karyotyped and their responses to restoration of USP18 activity assessed. Drug testing and tumorigenic assays were also performed. USP18 immunohistochemical staining in a large series of human leiomyosacomas was examined. USP18 −/− FVB/N mice spontaneously develop tumors predominantly on the back of the neck with most tumors evident between 6–12 months (80 % penetrance). Immunohistochemical characterization of the tumors confirmed they were leiomyosarcomas, which originate from smooth muscle. Restoration of USP18 activity in sarcoma-derived cell lines did not reduce anchorage dependent or independent growth or xenograft tumor formation demonstrating that these cells no longer require USP18 suppression for tumorigenesis. Karyotyping revealed that both tumor-derived cell lines were aneuploid with extra copies of chromosomes 3 and 15. Chromosome 15 contains the Myc locus and MYC is also amplified in human leiomyosarcomas. MYC protein levels were elevated in both murine leiomyosarcoma cell lines. Stabilized P53 protein was detected in a subset of these murine tumors, another feature of human leiomyosarcomas. Immunohistochemical analyses of USP18 in human leiomyosarcomas revealed a range of staining intensities with the highest USP18 expression in normal vascular smooth muscle. USP18 tissue array analysis of primary leiomyosarcomas from 89 patients with a clinical database revealed cases with reduced USP18 levels had a significantly

  2. Lack of Plasma Protein Hemopexin Results in Increased Duodenal Iron Uptake.

    Science.gov (United States)

    Fiorito, Veronica; Geninatti Crich, Simonetta; Silengo, Lorenzo; Aime, Silvio; Altruda, Fiorella; Tolosano, Emanuela

    2013-01-01

    The body concentration of iron is regulated by a fine equilibrium between absorption and losses of iron. Iron can be absorbed from diet as inorganic iron or as heme. Hemopexin is an acute phase protein that limits iron access to microorganisms. Moreover, it is the plasma protein with the highest binding affinity for heme and thus it mediates heme-iron recycling. Considering its involvement in iron homeostasis, it was postulated that hemopexin may play a role in the physiological absorption of inorganic iron. Hemopexin-null mice showed elevated iron deposits in enterocytes, associated with higher duodenal H-Ferritin levels and a significant increase in duodenal expression and activity of heme oxygenase. The expression of heme-iron and inorganic iron transporters was normal. The rate of iron absorption was assessed by measuring the amount of (57)Fe retained in tissues from hemopexin-null and wild-type animals after administration of an oral dose of (57)FeSO4 or of (57)Fe-labelled heme. Higher iron retention in the duodenum of hemopexin-null mice was observed as compared with normal mice. Conversely, iron transfer from enterocytes to liver and bone marrow was unaffected in hemopexin-null mice. The increased iron level in hemopexin-null duodenum can be accounted for by an increased iron uptake by enterocytes and storage in ferritins. These data indicate that the lack of hemopexin under physiological conditions leads to an enhanced duodenal iron uptake thus providing new insights to our understanding of body iron homeostasis.

  3. Triadin/Junctin double null mouse reveals a differential role for Triadin and Junctin in anchoring CASQ to the jSR and regulating Ca(2+ homeostasis.

    Directory of Open Access Journals (Sweden)

    Simona Boncompagni

    Full Text Available Triadin (Tdn and Junctin (Jct are structurally related transmembrane proteins thought to be key mediators of structural and functional interactions between calsequestrin (CASQ and ryanodine receptor (RyRs at the junctional sarcoplasmic reticulum (jSR. However, the specific contribution of each protein to the jSR architecture and to excitation-contraction (e-c coupling has not been fully established. Here, using mouse models lacking either Tdn (Tdn-null, Jct (Jct-null or both (Tdn/Jct-null, we identify Tdn as the main component of periodically located anchors connecting CASQ to the RyR-bearing jSR membrane. Both proteins proved to be important for the structural organization of jSR cisternae and retention of CASQ within them, but with different degrees of impact. Our results also suggest that the presence of CASQ is responsible for the wide lumen of the jSR cisternae. Using Ca(2+ imaging and Ca(2+ selective microelectrodes we found that changes in e-c coupling, SR Ca(2+content and resting [Ca(2+] in Jct, Tdn and Tdn/Jct-null muscles are directly correlated to the effect of each deletion on CASQ content and its organization within the jSR. These data suggest that in skeletal muscle the disruption of Tdn/CASQ link has a more profound effect on jSR architecture and myoplasmic Ca(2+ regulation than Jct/CASQ association.

  4. Interaction between gas cooking and GSTM1 null genotype in bronchial responsiveness: results from the European Community Respiratory Health Survey.

    NARCIS (Netherlands)

    Amaral, A.F.S.; Ramasamy, A.; Castro-Giner, F.; Minelli, C.; Accordini, S.; Sorheim, I.C.; Pin, I.; Kogevinas, M.; Jögi, R.; Balding, D.J.; Norbäck, D.; Verlato, G.; Olivieri, M.; Probst-Hensch, N.; Janson, C.; Zock, J.P.; Heinrich, J.; Jarvis, D.L.

    2014-01-01

    Background: Increased bronchial responsiveness is characteristic of asthma. Gas cooking, which is a major indoor source of the highly oxidant nitrogen dioxide, has been associated with respiratory symptoms and reduced lung function. However, little is known about the effect of gas cooking on

  5. Radiation Hardened NULL Convention Logic Asynchronous Circuit Design

    Directory of Open Access Journals (Sweden)

    Liang Zhou

    2015-10-01

    Full Text Available This paper proposes a radiation hardened NULL Convention Logic (NCL architecture that can recover from a single event latchup (SEL or single event upset (SEU fault without deadlock or any data loss. The proposed architecture is analytically proved to be SEL resistant, and by extension, proved to be SEU resistant. The SEL/SEU resistant version of a 3-stage full-word pipelined NCL 4 × 4 unsigned multiplier was implemented using the IBM cmrf8sf 130 nm 1.2 V process at the transistor level and simulated exhaustively with SEL fault injection to validate the proposed architectures. Compared with the original version, the SEL/SEU resilient version has 1.31× speed overhead, 2.74× area overhead, and 2.79× energy per operation overhead.

  6. The simple map for a single-null divertor tokamak

    International Nuclear Information System (INIS)

    Punjabi, A.; Verma, A.; Boozer, A.

    1996-01-01

    We present the simple map for a single-null divertor tokamak. The simple map is an area-preserving map based on the idea that magnetic field lines are a single-degree-of-freedom time-dependent Hamiltonian system, and that the basic features of such systems near the X-point are generic. We obtain the properties of this map and the resulting footprints of field lines on the divertor plate. These include the width of the stochastic layer, the edge safety factor, the area of the footprint and the amount of magnetic flux diverted. We give the safety factor profile, the average and median values of strike angles, lengths and the Liapunov exponents. We describe how the effects of magnetic perturbations can be included in the simple map. We show how the map can be applied to the problem of the determination of heat flux on the divertor plate in tokamaks. (Author)

  7. Status of the Visible Nulling Coronagraph Technology Demonstration Program

    Science.gov (United States)

    Clampin, M.; Lyon, R.

    2012-01-01

    We report on the development, sensing and control of the Vacuum Nuller Testbed to realize a Visible Nulling Coronagraphy (VNC) for exoplanet detection and characterization. The VNC is one of the few approaches that works with filled, segmented and sparse or diluted-aperture telescope systems. It thus spans a range of potential future NASA telescopes and could be flown as a separate instrument on such a future mission. NASA/Goddard Space Flight Center has an established effort to develop VNC technologies, and an incremental sequence of testbeds to advance this approach and its critical technologies. We will highlight results demonstrating the achievement of our TDEM contrast milestones, and highlight the performance of our wavefront sensing and control concept.

  8. Horizons in Matter:. Black Hole Hair Versus Null Big Bang

    Science.gov (United States)

    Bronnikov, K. A.; Zaslavskii, Oleg B.

    It is shown that only particular kinds of matter (in terms of the "radial" pressure-to-density ratio w) can coexist with Killing horizons in black hole or cosmological space-times. Thus, for arbitrary (not necessarily spherically symmetric) static black holes, admissible are vacuum matter (w = -1, i.e. the cosmological constant or its generalization with the same value of w) and matter with certain values of w between 0 and -1, in particular a gas of disordered cosmic strings (w = -1/3). If the cosmological evolution starts from a horizon (the so-called null big bang scenarios), this horizon can coexist with vacuum matter and certain kinds of phantom matter with w ≤ -3. It is concluded that normal matter in such scenarios is entirely created from vacuum.

  9. Cadmium modulates adipocyte functions in metallothionein-null mice

    Energy Technology Data Exchange (ETDEWEB)

    Kawakami, Takashige; Nishiyama, Kaori; Kadota, Yoshito; Sato, Masao; Inoue, Masahisa; Suzuki, Shinya, E-mail: suzukis@ph.bunri-u.ac.jp

    2013-11-01

    Our previous study has demonstrated that exposure to cadmium (Cd), a toxic heavy metal, causes a reduction of adipocyte size and the modulation of adipokine expression. To further investigate the significance of the Cd action, we studied the effect of Cd on the white adipose tissue (WAT) of metallothionein null (MT{sup −/−}) mice, which cannot form atoxic Cd–MT complexes and are used for evaluating Cd as free ions, and wild type (MT{sup +/+}) mice. Cd administration more significantly reduced the adipocyte size of MT{sup −/−} mice than that of MT{sup +/+} mice. Cd exposure also induced macrophage recruitment to WAT with an increase in the expression level of Ccl2 (MCP-1) in the MT{sup −/−} mice. The in vitro exposure of Cd to adipocytes induce triglyceride release into culture medium, decrease in the expression levels of genes involved in fatty acid synthesis and lipid hydrolysis at 24 h, and at 48 h increase in phosphorylation of the lipid-droplet-associated protein perilipin, which facilitates the degradation of stored lipids in adipocytes. Therefore, the reduction in adipocyte size by Cd may arise from an imbalance between lipid synthesis and lipolysis. In addition, the expression levels of leptin, adiponectin and resistin decreased in adipocytes. Taken together, exposure to Cd may induce unusually small adipocytes and modulate the expression of adipokines differently from the case of physiologically small adipocytes, and may accelerate the risk of developing insulin resistance and type 2 diabetes. - Highlights: • Cd causes a marked reduction in adipocyte size in MT-null mice. • Cd enhances macrophage migration into adipose tissue and disrupt adipokine secretion. • MT gene alleviates Cd-induced adipocyte dysfunctions. • Cd enhances the degradation of stored lipids in adipocytes, mediated by perilipin. • Cd induces unusually small adipocytes and the abnormal expression of adipokines.

  10. Dinucleotide controlled null models for comparative RNA gene prediction

    Directory of Open Access Journals (Sweden)

    Gesell Tanja

    2008-05-01

    Full Text Available Abstract Background Comparative prediction of RNA structures can be used to identify functional noncoding RNAs in genomic screens. It was shown recently by Babak et al. [BMC Bioinformatics. 8:33] that RNA gene prediction programs can be biased by the genomic dinucleotide content, in particular those programs using a thermodynamic folding model including stacking energies. As a consequence, there is need for dinucleotide-preserving control strategies to assess the significance of such predictions. While there have been randomization algorithms for single sequences for many years, the problem has remained challenging for multiple alignments and there is currently no algorithm available. Results We present a program called SISSIz that simulates multiple alignments of a given average dinucleotide content. Meeting additional requirements of an accurate null model, the randomized alignments are on average of the same sequence diversity and preserve local conservation and gap patterns. We make use of a phylogenetic substitution model that includes overlapping dependencies and site-specific rates. Using fast heuristics and a distance based approach, a tree is estimated under this model which is used to guide the simulations. The new algorithm is tested on vertebrate genomic alignments and the effect on RNA structure predictions is studied. In addition, we directly combined the new null model with the RNAalifold consensus folding algorithm giving a new variant of a thermodynamic structure based RNA gene finding program that is not biased by the dinucleotide content. Conclusion SISSIz implements an efficient algorithm to randomize multiple alignments preserving dinucleotide content. It can be used to get more accurate estimates of false positive rates of existing programs, to produce negative controls for the training of machine learning based programs, or as standalone RNA gene finding program. Other applications in comparative genomics that require

  11. Dinucleotide controlled null models for comparative RNA gene prediction.

    Science.gov (United States)

    Gesell, Tanja; Washietl, Stefan

    2008-05-27

    Comparative prediction of RNA structures can be used to identify functional noncoding RNAs in genomic screens. It was shown recently by Babak et al. [BMC Bioinformatics. 8:33] that RNA gene prediction programs can be biased by the genomic dinucleotide content, in particular those programs using a thermodynamic folding model including stacking energies. As a consequence, there is need for dinucleotide-preserving control strategies to assess the significance of such predictions. While there have been randomization algorithms for single sequences for many years, the problem has remained challenging for multiple alignments and there is currently no algorithm available. We present a program called SISSIz that simulates multiple alignments of a given average dinucleotide content. Meeting additional requirements of an accurate null model, the randomized alignments are on average of the same sequence diversity and preserve local conservation and gap patterns. We make use of a phylogenetic substitution model that includes overlapping dependencies and site-specific rates. Using fast heuristics and a distance based approach, a tree is estimated under this model which is used to guide the simulations. The new algorithm is tested on vertebrate genomic alignments and the effect on RNA structure predictions is studied. In addition, we directly combined the new null model with the RNAalifold consensus folding algorithm giving a new variant of a thermodynamic structure based RNA gene finding program that is not biased by the dinucleotide content. SISSIz implements an efficient algorithm to randomize multiple alignments preserving dinucleotide content. It can be used to get more accurate estimates of false positive rates of existing programs, to produce negative controls for the training of machine learning based programs, or as standalone RNA gene finding program. Other applications in comparative genomics that require randomization of multiple alignments can be considered. SISSIz

  12. Does horizon entropy satisfy a quantum null energy conjecture?

    Science.gov (United States)

    Fu, Zicao; Marolf, Donald

    2016-12-01

    A modern version of the idea that the area of event horizons gives 4G times an entropy is the Hubeny-Rangamani causal holographic information (CHI) proposal for holographic field theories. Given a region R of a holographic QFTs, CHI computes A/4G on a certain cut of an event horizon in the gravitational dual. The result is naturally interpreted as a coarse-grained entropy for the QFT. CHI is known to be finitely greater than the fine-grained Hubeny-Rangamani-Takayanagi (HRT) entropy when \\partial R lies on a Killing horizon of the QFT spacetime, and in this context satisfies other non-trivial properties expected of an entropy. Here we present evidence that it also satisfies the quantum null energy condition (QNEC), which bounds the second derivative of the entropy of a quantum field theory on one side of a non-expanding null surface by the flux of stress-energy across the surface. In particular, we show CHI to satisfy the QNEC in 1  +  1 holographic CFTs when evaluated in states dual to conical defects in AdS3. This surprising result further supports the idea that CHI defines a useful notion of coarse-grained holographic entropy, and suggests unprecedented bounds on the rate at which bulk horizon generators emerge from a caustic. To supplement our motivation, we include an appendix deriving a corresponding coarse-grained generalized second law for 1  +  1 holographic CFTs perturbatively coupled to dilaton gravity.

  13. 3D Solar Null Point Reconnection MHD Simulations

    Science.gov (United States)

    Baumann, G.; Galsgaard, K.; Nordlund, Å.

    2013-06-01

    Numerical MHD simulations of 3D reconnection events in the solar corona have improved enormously over the last few years, not only in resolution, but also in their complexity, enabling more and more realistic modeling. Various ways to obtain the initial magnetic field, different forms of solar atmospheric models as well as diverse driving speeds and patterns have been employed. This study considers differences between simulations with stratified and non-stratified solar atmospheres, addresses the influence of the driving speed on the plasma flow and energetics, and provides quantitative formulas for mapping electric fields and dissipation levels obtained in numerical simulations to the corresponding solar quantities. The simulations start out from a potential magnetic field containing a null-point, obtained from a Solar and Heliospheric Observatory (SOHO) Michelson Doppler Imager (MDI) magnetogram magnetogram extrapolation approximately 8 hours before a C-class flare was observed. The magnetic field is stressed with a boundary motion pattern similar to - although simpler than - horizontal motions observed by SOHO during the period preceding the flare. The general behavior is nearly independent of the driving speed, and is also very similar in stratified and non-stratified models, provided only that the boundary motions are slow enough. The boundary motions cause a build-up of current sheets, mainly in the fan-plane of the magnetic null-point, but do not result in a flare-like energy release. The additional free energy required for the flare could have been partly present in non-potential form at the initial state, with subsequent additions from magnetic flux emergence or from components of the boundary motion that were not represented by the idealized driving pattern.

  14. Surprising structures hiding in Penrose’s future null infinity

    Science.gov (United States)

    Newman, Ezra T.

    2017-07-01

    Since the late1950s, almost all discussions of asymptotically flat (Einstein-Maxwell) space-times have taken place in the context of Penrose’s null infinity, I+. In addition, almost all calculations have used the Bondi coordinate and tetrad systems. Beginning with a known asymptotically flat solution to the Einstein-Maxwell equations, we show first, that there are other natural coordinate systems, near I+, (analogous to light-cones in flat-space) that are based on (asymptotically) shear-free null geodesic congruences (analogous to the flat-space case). Using these new coordinates and their associated tetrad, we define the complex dipole moment, (the mass dipole plus i times angular momentum), from the l  =  1 harmonic coefficient of a component of the asymptotic Weyl tensor. Second, from this definition, from the Bianchi identities and from the Bondi-Sachs mass and linear momentum, we show that there exists a large number of results—identifications and dynamics—identical to those of classical mechanics and electrodynamics. They include, among many others, {P}=M{v}+..., {L}= {r} × {P} , spin, Newton’s second law with the rocket force term (\\dotM v) and radiation reaction, angular momentum conservation and others. All these relations take place in the rather mysterious H-space rather than in space-time. This leads to the enigma: ‘why do these well known relations of classical mechanics take place in H-space?’ and ‘What is the physical meaning of H-space?’

  15. Is PMI the Hypothesis or the Null Hypothesis?

    Science.gov (United States)

    Tarone, Aaron M; Sanford, Michelle R

    2017-09-01

    Over the past several decades, there have been several strident exchanges regarding whether forensic entomologists estimate the postmortem interval (PMI), minimum PMI, or something else. During that time, there has been a proliferation of terminology reflecting this concern regarding "what we do." This has been a frustrating conversation for some in the community because much of this debate appears to be centered on what assumptions are acknowledged directly and which are embedded within a list of assumptions (or ignored altogether) in the literature and in case reports. An additional component of the conversation centers on a concern that moving away from the use of certain terminology like PMI acknowledges limitations and problems that would make the application of entomology appear less useful in court-a problem for lawyers, but one that should not be problematic for scientists in the forensic entomology community, as uncertainty is part of science that should and can be presented effectively in the courtroom (e.g., population genetic concepts in forensics). Unfortunately, a consequence of the way this conversation is conducted is that even as all involved in the debate acknowledge the concerns of their colleagues, parties continue to talk past one another advocating their preferred terminology. Progress will not be made until the community recognizes that all of the terms under consideration take the form of null hypothesis statements and that thinking about "what we do" as a null hypothesis has useful legal and scientific ramifications that transcend arguments over the usage of preferred terminology. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Observation of a 3D Magnetic Null Point

    Energy Technology Data Exchange (ETDEWEB)

    Romano, P.; Falco, M. [INAF—Osservatorio Astrofisico di Catania, Via S. Sofia 78, I-95123 Catania (Italy); Guglielmino, S. L.; Murabito, M., E-mail: prom@oact.inaf.it [Dipartimento di Fisica e Astronomia—Sezione Astrofisica, Università di Catania, Via S. Sofia 78, I-95123 Catania (Italy)

    2017-03-10

    We describe high-resolution observations of a GOES B-class flare characterized by a circular ribbon at the chromospheric level, corresponding to the network at the photospheric level. We interpret the flare as a consequence of a magnetic reconnection event that occurred at a three-dimensional (3D) coronal null point located above the supergranular cell. The potential field extrapolation of the photospheric magnetic field indicates that the circular chromospheric ribbon is cospatial with the fan footpoints, while the ribbons of the inner and outer spines look like compact kernels. We found new interesting observational aspects that need to be explained by models: (1) a loop corresponding to the outer spine became brighter a few minutes before the onset of the flare; (2) the circular ribbon was formed by several adjacent compact kernels characterized by a size of 1″–2″; (3) the kernels with a stronger intensity emission were located at the outer footpoint of the darker filaments, departing radially from the center of the supergranular cell; (4) these kernels started to brighten sequentially in clockwise direction; and (5) the site of the 3D null point and the shape of the outer spine were detected by RHESSI in the low-energy channel between 6.0 and 12.0 keV. Taking into account all these features and the length scales of the magnetic systems involved in the event, we argue that the low intensity of the flare may be ascribed to the low amount of magnetic flux and to its symmetric configuration.

  17. Double gene deletion reveals the lack of cooperation between PPARα and PPARβ in skeletal muscle

    International Nuclear Information System (INIS)

    Bedu, E.; Desplanches, D.; Pequignot, J.; Bordier, B.; Desvergne, B.

    2007-01-01

    The peroxisome proliferator-activated receptors (PPARs) are involved in the regulation of most of the pathways linked to lipid metabolism. PPARα and PPARβ isotypes are known to regulate muscle fatty acid oxidation and a reciprocal compensation of their function has been proposed. Herein, we investigated muscle contractile and metabolic phenotypes in PPARα-/-, PPARβ-/-, and double PPARα-/- β-/- mice. Heart and soleus muscle analyses show that the deletion of PPARα induces a decrease of the HAD activity (β-oxidation) while soleus contractile phenotype remains unchanged. A PPARβ deletion alone has no effect. However, these mild phenotypes are not due to a reciprocal compensation of PPARβ and PPARα functions since double gene deletion PPARα-PPARβ mostly reproduces the null PPARα-mediated reduced β-oxidation, in addition to a shift from fast to slow fibers. In conclusion, PPARβ is not required for maintaining skeletal muscle metabolic activity and does not compensate the lack of PPARα in PPARα null mice

  18. Chronic Toxoplasma gondii in Nurr1-null heterozygous mice exacerbates elevated open field activity.

    Science.gov (United States)

    Eells, Jeffrey B; Varela-Stokes, Andrea; Guo-Ross, Shirley X; Kummari, Evangel; Smith, Holly M; Cox, Erin; Lindsay, David S

    2015-01-01

    Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population) and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%), genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/-) mice and wild-type (+/+) mice were evaluate using an emergence test, activity in an open field and with a novel object, response to bobcat urine and prepulse inhibition of the acoustic startle response (PPI) prior to and 6 weeks after infection with T. gondii. In the emergence test, T. gondii infection significantly decreased the amount of time spent in the cylinder. Toxoplasma gondii infection significantly elevated open field activity in both +/+ and +/- mice but this increase was significantly exacerbated in +/- mice. T. gondii infection reduced PPI in male +/- mice but this was not statistically significant. Aversion to bobcat urine was abolished by T. gondii infection in +/+ mice. In female +/- mice, aversion to bobcat urine remained after T. gondii infection while the male +/- mice showed no aversion to bobcat urine. Antibody titers of infected mice were a critical variable associated with changes in open field activity, such that an inverted U shaped relationship existed between antibody titers and the percent change in open field activity with a significant increase in activity at low and medium antibody titers but no effect at high antibody titers. These data demonstrate that the Nurr1 +/- genotype predisposes mice to T. gondii-induced alterations in behaviors that involve dopamine neurotransmission and are associated with symptoms of schizophrenia. We propose that these alterations in murine behavior were due to further exacerbation of the altered dopamine neurotransmission in Nurr1 +/- mice.

  19. Chronic Toxoplasma gondii in Nurr1-null heterozygous mice exacerbates elevated open field activity.

    Directory of Open Access Journals (Sweden)

    Jeffrey B Eells

    Full Text Available Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%, genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/- mice and wild-type (+/+ mice were evaluate using an emergence test, activity in an open field and with a novel object, response to bobcat urine and prepulse inhibition of the acoustic startle response (PPI prior to and 6 weeks after infection with T. gondii. In the emergence test, T. gondii infection significantly decreased the amount of time spent in the cylinder. Toxoplasma gondii infection significantly elevated open field activity in both +/+ and +/- mice but this increase was significantly exacerbated in +/- mice. T. gondii infection reduced PPI in male +/- mice but this was not statistically significant. Aversion to bobcat urine was abolished by T. gondii infection in +/+ mice. In female +/- mice, aversion to bobcat urine remained after T. gondii infection while the male +/- mice showed no aversion to bobcat urine. Antibody titers of infected mice were a critical variable associated with changes in open field activity, such that an inverted U shaped relationship existed between antibody titers and the percent change in open field activity with a significant increase in activity at low and medium antibody titers but no effect at high antibody titers. These data demonstrate that the Nurr1 +/- genotype predisposes mice to T. gondii-induced alterations in behaviors that involve dopamine neurotransmission and are associated with symptoms of schizophrenia. We propose that these alterations in murine behavior were due to further exacerbation of the altered dopamine neurotransmission in Nurr1 +/- mice.

  20. Genetic similarity of soybean genotypes revealed by seed protein

    Directory of Open Access Journals (Sweden)

    Nikolić Ana

    2005-01-01

    Full Text Available More accurate and complete descriptions of genotypes could help determinate future breeding strategies and facilitate introgression of new genotypes in current soybean genetic pool. The objective of this study was to characterize 20 soybean genotypes from the Maize Research Institute "Zemun Polje" collection, which have good agronomic performances, high yield, lodging and drought resistance, and low shuttering by seed proteins as biochemical markers. Seed proteins were isolated and separated by PAA electrophoresis. On the basis of the presence/absence of protein fractions coefficients of similarity were calculated as Dice and Roger and Tanamoto coefficient between pairs of genotypes. The similarity matrix was submitted for hierarchical cluster analysis of un weighted pair group using arithmetic average (UPGMA method and necessary computation were performed using NTSYS-pc program. Protein seed analysis confirmed low level of genetic diversity in soybean. The highest genetic similarity was between genotypes P9272 and Kador. According to obtained results, soybean genotypes were assigned in two larger groups and coefficients of similarity showed similar results. Because of the lack of pedigree data for analyzed genotypes, correspondence with marker data could not be determined. In plant with a narrow genetic base in their gene pool, such as soybean, protein markers may not be sufficient for characterization and study of genetic diversity.

  1. High-throughput drug screen identifies chelerythrine as a selective inducer of death in a TSC2-null setting.

    Science.gov (United States)

    Medvetz, Doug; Sun, Yang; Li, Chenggang; Khabibullin, Damir; Balan, Murugabaskar; Parkhitko, Andrey; Priolo, Carmen; Asara, John M; Pal, Soumitro; Yu, Jane; Henske, Elizabeth P

    2015-01-01

    Tuberous sclerosis complex (TSC) is an autosomal dominant syndrome associated with tumors of the brain, heart, kidney, and lung. The TSC protein complex inhibits the mammalian or mechanistic target of rapamycin complex 1 (mTORC1). Inhibitors of mTORC1, including rapamycin, induce a cytostatic response in TSC tumors, resulting in temporary disease stabilization and prompt regrowth when treatment is stopped. The lack of TSC-specific cytotoxic therapies represents an important unmet clinical need. Using a high-throughput chemical screen in TSC2-deficient, patient-derived cells, we identified a series of molecules antagonized by rapamycin and therefore selective for cells with mTORC1 hyperactivity. In particular, the cell-permeable alkaloid chelerythrine induced reactive oxygen species (ROS) and depleted glutathione (GSH) selectively in TSC2-null cells based on metabolic profiling. N-acetylcysteine or GSH cotreatment protected TSC2-null cells from chelerythrine's effects, indicating that chelerythrine-induced cell death is ROS dependent. Induction of heme-oxygenase-1 (HMOX1/HO-1) with hemin also blocked chelerythrine-induced cell death. In vivo, chelerythrine inhibited the growth of TSC2-null xenograft tumors with no evidence of systemic toxicity with daily treatment over an extended period of time. This study reports the results of a bioactive compound screen and the identification of a potential lead candidate that acts via a novel oxidative stress-dependent mechanism to selectively induce necroptosis in TSC2-deficient tumors. This study demonstrates that TSC2-deficient tumor cells are hypersensitive to oxidative stress-dependent cell death, and provide critical proof of concept that TSC2-deficient cells can be therapeutically targeted without the use of a rapalog to induce a cell death response. ©2014 American Association for Cancer Research.

  2. Qualification of a Null Lens Using Image-Based Phase Retrieval

    Science.gov (United States)

    Bolcar, Matthew R.; Aronstein, David L.; Hill, Peter C.; Smith, J. Scott; Zielinski, Thomas P.

    2012-01-01

    In measuring the figure error of an aspheric optic using a null lens, the wavefront contribution from the null lens must be independently and accurately characterized in order to isolate the optical performance of the aspheric optic alone. Various techniques can be used to characterize such a null lens, including interferometry, profilometry and image-based methods. Only image-based methods, such as phase retrieval, can measure the null-lens wavefront in situ - in single-pass, and at the same conjugates and in the same alignment state in which the null lens will ultimately be used - with no additional optical components. Due to the intended purpose of a Dull lens (e.g., to null a large aspheric wavefront with a near-equal-but-opposite spherical wavefront), characterizing a null-lens wavefront presents several challenges to image-based phase retrieval: Large wavefront slopes and high-dynamic-range data decrease the capture range of phase-retrieval algorithms, increase the requirements on the fidelity of the forward model of the optical system, and make it difficult to extract diagnostic information (e.g., the system F/#) from the image data. In this paper, we present a study of these effects on phase-retrieval algorithms in the context of a null lens used in component development for the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission. Approaches for mitigation are also discussed.

  3. An equation satisfied by the tangent to a shear-free, geodesic, null congruence

    International Nuclear Information System (INIS)

    Hogan, P.A.; Dublin Inst. for Advanced Studies

    1987-01-01

    A tensorial equation satisfied by the tangent to a shear-free geodesic, null congruence is presented. If the congruence is neither twist-free nor expansion-free then the equation defines a second, unique, null direction previously obtained, using the spinor formalism, by Somers. Some further properties of the equation are discussed. (orig.)

  4. Achilles tendons from decorin- and biglycan-null mouse models have inferior mechanical and structural properties predicted by an image-based empirical damage model.

    Science.gov (United States)

    Gordon, J A; Freedman, B R; Zuskov, A; Iozzo, R V; Birk, D E; Soslowsky, L J

    2015-07-16

    Achilles tendons are a common source of pain and injury, and their pathology may originate from aberrant structure function relationships. Small leucine rich proteoglycans (SLRPs) influence mechanical and structural properties in a tendon-specific manner. However, their roles in the Achilles tendon have not been defined. The objective of this study was to evaluate the mechanical and structural differences observed in mouse Achilles tendons lacking class I SLRPs; either decorin or biglycan. In addition, empirical modeling techniques based on mechanical and image-based measures were employed. Achilles tendons from decorin-null (Dcn(-/-)) and biglycan-null (Bgn(-/-)) C57BL/6 female mice (N=102) were used. Each tendon underwent a dynamic mechanical testing protocol including simultaneous polarized light image capture to evaluate both structural and mechanical properties of each Achilles tendon. An empirical damage model was adapted for application to genetic variation and for use with image based structural properties to predict tendon dynamic mechanical properties. We found that Achilles tendons lacking decorin and biglycan had inferior mechanical and structural properties that were age dependent; and that simple empirical models, based on previously described damage models, were predictive of Achilles tendon dynamic modulus in both decorin- and biglycan-null mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Causal null hypotheses of sustained treatment strategies: What can be tested with an instrumental variable?

    Science.gov (United States)

    Swanson, Sonja A; Labrecque, Jeremy; Hernán, Miguel A

    2018-05-02

    Sometimes instrumental variable methods are used to test whether a causal effect is null rather than to estimate the magnitude of a causal effect. However, when instrumental variable methods are applied to time-varying exposures, as in many Mendelian randomization studies, it is unclear what causal null hypothesis is tested. Here, we consider different versions of causal null hypotheses for time-varying exposures, show that the instrumental variable conditions alone are insufficient to test some of them, and describe additional assumptions that can be made to test a wider range of causal null hypotheses, including both sharp and average causal null hypotheses. Implications for interpretation and reporting of instrumental variable results are discussed.

  6. Continuous development of current sheets near and away from magnetic nulls

    International Nuclear Information System (INIS)

    Kumar, Sanjay; Bhattacharyya, R.

    2016-01-01

    The presented computations compare the strength of current sheets which develop near and away from the magnetic nulls. To ensure the spontaneous generation of current sheets, the computations are performed congruently with Parker's magnetostatic theorem. The simulations evince current sheets near two dimensional and three dimensional magnetic nulls as well as away from them. An important finding of this work is in the demonstration of comparative scaling of peak current density with numerical resolution, for these different types of current sheets. The results document current sheets near two dimensional magnetic nulls to have larger strength while exhibiting a stronger scaling than the current sheets close to three dimensional magnetic nulls or away from any magnetic null. The comparative scaling points to a scenario where the magnetic topology near a developing current sheet is important for energetics of the subsequent reconnection.

  7. The epidermis of grhl3-null mice displays altered lipid processing and cellular hyperproliferation.

    Science.gov (United States)

    Ting, Stephen B; Caddy, Jacinta; Wilanowski, Tomasz; Auden, Alana; Cunningham, John M; Elias, Peter M; Holleran, Walter M; Jane, Stephen M

    2005-04-01

    The presence of an impermeable surface barrier is an essential homeostatic mechanism in almost all living organisms. We have recently described a novel gene that is critical for the developmental instruction and repair of the integument in mammals. This gene, Grainy head-like 3 (Grhl3) is a member of a large family of transcription factors that are homologs of the Drosophila developmental gene grainy head (grh). Mice lacking Grhl3 fail to form an adequate skin barrier, and die at birth due to dehydration. These animals are also unable to repair the epidermis, exhibiting failed wound healing in both fetal and adult stages of development. These defects are due, in part, to diminished expression of a Grhl3 target gene, Transglutaminase 1 (TGase 1), which encodes a key enzyme involved in cross-linking of epidermal structural proteins and lipids into the cornified envelope (CE). Remarkably, the Drosophila grh gene plays an analogous role, regulating enzymes involved in the generation of quinones, which are essential for cross-linking structural components of the fly epidermis. In an extension of our initial analyses, we focus this report on additional defects observed in the Grhl3-null epidermis, namely defective extra-cellular lipid processing, altered lamellar lipid architecture and cellular hyperproliferation. These abnormalities suggest that Grhl3 plays diverse mechanistic roles in maintaining homeostasis in the skin.

  8. Perturbed desmosomal cadherin expression in grainy head-like 1-null mice.

    Science.gov (United States)

    Wilanowski, Tomasz; Caddy, Jacinta; Ting, Stephen B; Hislop, Nikki R; Cerruti, Loretta; Auden, Alana; Zhao, Lin-Lin; Asquith, Stephen; Ellis, Sarah; Sinclair, Rodney; Cunningham, John M; Jane, Stephen M

    2008-03-19

    In Drosophila, the grainy head (grh) gene plays a range of key developmental roles through the regulation of members of the cadherin gene family. We now report that mice lacking the grh homologue grainy head-like 1 (Grhl1) exhibit hair and skin phenotypes consistent with a reduction in expression of the genes encoding the desmosomal cadherin, desmoglein 1 (Dsg1). Grhl1-null mice show an initial delay in coat growth, and older mice exhibit hair loss as a result of poor anchoring of the hair shaft in the follicle. The mice also develop palmoplantar keratoderma, analogous to humans with DSG1 mutations. Sequence analysis, DNA binding, and chromatin immunoprecipitation experiments demonstrate that the human and mouse Dsg1 promoters are direct targets of GRHL1. Ultrastructural analysis reveals reduced numbers of abnormal desmosomes in the interfollicular epidermis. These findings establish GRHL1 as an important regulator of the Dsg1 genes in the context of hair anchorage and epidermal differentiation, and suggest that cadherin family genes are key targets of the grainy head-like genes across 700 million years of evolution.

  9. DnaSAM: Software to perform neutrality testing for large datasets with complex null models.

    Science.gov (United States)

    Eckert, Andrew J; Liechty, John D; Tearse, Brandon R; Pande, Barnaly; Neale, David B

    2010-05-01

    Patterns of DNA sequence polymorphisms can be used to understand the processes of demography and adaptation within natural populations. High-throughput generation of DNA sequence data has historically been the bottleneck with respect to data processing and experimental inference. Advances in marker technologies have largely solved this problem. Currently, the limiting step is computational, with most molecular population genetic software allowing a gene-by-gene analysis through a graphical user interface. An easy-to-use analysis program that allows both high-throughput processing of multiple sequence alignments along with the flexibility to simulate data under complex demographic scenarios is currently lacking. We introduce a new program, named DnaSAM, which allows high-throughput estimation of DNA sequence diversity and neutrality statistics from experimental data along with the ability to test those statistics via Monte Carlo coalescent simulations. These simulations are conducted using the ms program, which is able to incorporate several genetic parameters (e.g. recombination) and demographic scenarios (e.g. population bottlenecks). The output is a set of diversity and neutrality statistics with associated probability values under a user-specified null model that are stored in easy to manipulate text file. © 2009 Blackwell Publishing Ltd.

  10. Nulling interferometry for the darwin mission: laboratory demonstration experiment

    Science.gov (United States)

    Ollivier, Marc; Léger, Alain; Sekulic, Predrag; Labèque, Alain; Michel, Guy

    2017-11-01

    The DARWIN mission is a project of the European Space Agency that should allow around 2012 the search for extrasolar planets and a spectral analysis of their potential atmosphere in order to evidence gases and particularly tracers of life. The principle of the instrument is based on the Bracewell nulling interferometer. It allows high angular resolution and high dynamic range. However, this concept, proposed more than 20 years ago, has never been experimentally demonstrated in the thermal infrared with high levels of extinction. We present here a laboratory monochromatic experiment dedicated to this goal. A theoretical and numerical approach of the question highlights a strong difficulty: the need for very clean and homogeneous wavefronts, in terms of intensity, phase and polarisation distribution. A classical interferometric approach appears to be insufficient to reach our goals. We have shown theoretically then numerically that this difficulty can be surpassed if we perform an optical filtering of the interfering beams. This technique allows us to decrease strongly the optical requirements and to view very high interferometric contrast measurements with commercial optical pieces. We present here a laboratory interferometer working at 10,6 microns, and implementing several techniques of optical filtering (pinholes and single-mode waveguides), its realisation, and its first promising results. We particularly present measurements that exhibit stable visibility levels better than 99,9% that is to say extinction levels better than 1000.

  11. Constrained Null Space Component Analysis for Semiblind Source Separation Problem.

    Science.gov (United States)

    Hwang, Wen-Liang; Lu, Keng-Shih; Ho, Jinn

    2018-02-01

    The blind source separation (BSS) problem extracts unknown sources from observations of their unknown mixtures. A current trend in BSS is the semiblind approach, which incorporates prior information on sources or how the sources are mixed. The constrained independent component analysis (ICA) approach has been studied to impose constraints on the famous ICA framework. We introduced an alternative approach based on the null space component (NCA) framework and referred to the approach as the c-NCA approach. We also presented the c-NCA algorithm that uses signal-dependent semidefinite operators, which is a bilinear mapping, as signatures for operator design in the c-NCA approach. Theoretically, we showed that the source estimation of the c-NCA algorithm converges with a convergence rate dependent on the decay of the sequence, obtained by applying the estimated operators on corresponding sources. The c-NCA can be formulated as a deterministic constrained optimization method, and thus, it can take advantage of solvers developed in optimization society for solving the BSS problem. As examples, we demonstrated electroencephalogram interference rejection problems can be solved by the c-NCA with proximal splitting algorithms by incorporating a sparsity-enforcing separation model and considering the case when reference signals are available.

  12. A null relationship between media multitasking and well-being.

    Directory of Open Access Journals (Sweden)

    Shui-I Shih

    Full Text Available There is a rapidly increasing trend in media-media multitasking or MMM (using two or more media concurrently. In a recent conference, scholars from diverse disciplines expressed concerns that indulgence in MMM may compromise well-being and/or cognitive abilities. However, research on MMM's impacts is too sparse to inform the general public and policy makers whether MMM should be encouraged, managed, or minimized. The primary purpose of the present study was to develop an innovative computerized instrument--the Survey of the Previous Day (SPD--to quantify MMM as well as media-nonmedia and nonmedia-nonmedia multitasking and sole-tasking. The secondary purpose was to examine whether these indices could predict a sample of well-being related, psychosocial measures. In the SPD, participants first recalled (typed what they did during each hour of the previous day. In later parts of the SPD, participants analysed activities and their timing and duration for each hour of the previous day, while relevant recall was on display. Participants also completed the Media Use Questionnaire. The results showed non-significant relationship between tasking measures and well-being related measures. Given how little is known about the associations between MMM and well-being, the null results may offer some general reassurance to those who are apprehensive about negative impacts of MMM.

  13. A Null Relationship between Media Multitasking and Well-Being

    Science.gov (United States)

    Shih, Shui-I

    2013-01-01

    There is a rapidly increasing trend in media-media multitasking or MMM (using two or more media concurrently). In a recent conference, scholars from diverse disciplines expressed concerns that indulgence in MMM may compromise well-being and/or cognitive abilities. However, research on MMM's impacts is too sparse to inform the general public and policy makers whether MMM should be encouraged, managed, or minimized. The primary purpose of the present study was to develop an innovative computerized instrument – the Survey of the Previous Day (SPD) – to quantify MMM as well as media-nonmedia and nonmedia-nonmedia multitasking and sole-tasking. The secondary purpose was to examine whether these indices could predict a sample of well-being related, psychosocial measures. In the SPD, participants first recalled (typed) what they did during each hour of the previous day. In later parts of the SPD, participants analysed activities and their timing and duration for each hour of the previous day, while relevant recall was on display. Participants also completed the Media Use Questionnaire. The results showed non-significant relationship between tasking measures and well-being related measures. Given how little is known about the associations between MMM and well-being, the null results may offer some general reassurance to those who are apprehensive about negative impacts of MMM. PMID:23691236

  14. Conical twist fields and null polygonal Wilson loops

    Science.gov (United States)

    Castro-Alvaredo, Olalla A.; Doyon, Benjamin; Fioravanti, Davide

    2018-06-01

    Using an extension of the concept of twist field in QFT to space-time (external) symmetries, we study conical twist fields in two-dimensional integrable QFT. These create conical singularities of arbitrary excess angle. We show that, upon appropriate identification between the excess angle and the number of sheets, they have the same conformal dimension as branch-point twist fields commonly used to represent partition functions on Riemann surfaces, and that both fields have closely related form factors. However, we show that conical twist fields are truly different from branch-point twist fields. They generate different operator product expansions (short distance expansions) and form factor expansions (large distance expansions). In fact, we verify in free field theories, by re-summing form factors, that the conical twist fields operator product expansions are correctly reproduced. We propose that conical twist fields are the correct fields in order to understand null polygonal Wilson loops/gluon scattering amplitudes of planar maximally supersymmetric Yang-Mills theory.

  15. Lovelock vacua with a recurrent null vector field

    Science.gov (United States)

    Ortaggio, Marcello

    2018-02-01

    Vacuum solutions of Lovelock gravity in the presence of a recurrent null vector field (a subset of Kundt spacetimes) are studied. We first discuss the general field equations, which constrain both the base space and the profile functions. While choosing a "generic" base space puts stronger constraints on the profile, in special cases there also exist solutions containing arbitrary functions (at least for certain values of the coupling constants). These and other properties (such as the p p - waves subclass and the overlap with VSI, CSI and universal spacetimes) are subsequently analyzed in more detail in lower dimensions n =5 , 6 as well as for particular choices of the base manifold. The obtained solutions describe various classes of nonexpanding gravitational waves propagating, e.g., in Nariai-like backgrounds M2×Σn -2. An Appendix contains some results about general (i.e., not necessarily Kundt) Lovelock vacua of Riemann type III/N and of Weyl and traceless-Ricci type III/N. For example, it is pointed out that for theories admitting a triply degenerate maximally symmetric vacuum, all the (reduced) field equations are satisfied identically, giving rise to large classes of exact solutions.

  16. Screening cotton genotypes for seedling drought tolerance

    Directory of Open Access Journals (Sweden)

    Penna Julio C. Viglioni

    1998-01-01

    Full Text Available The objectives of this study were to adapt a screening method previously used to assess seedling drought tolerance in cereals for use in cotton (Gossypium hirsutum L. and to identify tolerant accessions among a wide range of genotypes. Ninety genotypes were screened in seven growth chamber experiments. Fifteen-day-old seedlings were subjected to four 4-day drought cycles, and plant survival was evaluated after each cycle. Three cycles are probably the minimum required in cotton work. Significant differences (at the 0.05 level or lower among entries were obtained in four of the seven experiments. A "confirmation test" with entries previously evaluated as "tolerant" (high survival and "susceptible" (low survival was run. A number of entries duplicated their earlier performance, but others did not, which indicates the need to reevaluate selections. Germplasms considered tolerant included: `IAC-13-1', `IAC-RM4-SM5', `Minas Sertaneja', `Acala 1517E-1' and `4521'. In general, the technique is simple, though time-consuming, with practical value for screening a large number of genotypes. Results from the screening tests generally agreed with field information. The screening procedure is suitable to select tolerant accessions from among a large number of entries in germplasm collections as a preliminary step in breeding for drought tolerance. This research also demonstrated the need to characterize the internal lack of uniformity in growth chambers to allow for adequate designs of experiments.

  17. Common genotypes of hepatitis B virus

    International Nuclear Information System (INIS)

    Idrees, M.; Khan, S.; Riazuddin, S.

    2004-01-01

    Objective: To find out the frequency of common genotypes of hepatitis-B virus (HBV). Subjects and Methods: HBV genotypes were determined in 112 HBV DNA positive sera by a simple and precise molecular genotyping system base on PCR using type-specific primers for the determination of genotypes of HBV A through H. Results: Four genotypes (A,B,C and D) out of total eight reported genotypes so far were identified. Genotypes A, B and C were predominant. HBV genotype C was the most predominant in this collection, appearing in 46 samples (41.7%). However, the genotypes of a total of 5 (4.46%) samples could not be determined with the present genotyping system. Mixed genotypes were seen in 8(7.14% HBV) isolates. Five of these were infected with genotypes A/D whereas two were with genotypes C/D. One patient was infected with 4 genotypes (A/B/C/D). Genotype A (68%) was predominant in Sindh genotype C was most predominant in North West Frontier Province (NWFP) (68.96) whereas genotype C and B were dominant in Punjab (39.65% and 25.86% respectively). Conclusion: All the four common genotypes of HBV found worldwide (A,B,C and D) were isolated. Genotype C is the predominant Genotypes B and C are predominant in Punjab and N.W.F.P. whereas genotype A is predominant in Sindh. (author)

  18. Two-year body composition analyses of long-lived GHR null mice.

    Science.gov (United States)

    Berryman, Darlene E; List, Edward O; Palmer, Amanda J; Chung, Min-Yu; Wright-Piekarski, Jacob; Lubbers, Ellen; O'Connor, Patrick; Okada, Shigeru; Kopchick, John J

    2010-01-01

    Growth hormone receptor gene-disrupted (GHR-/-) mice exhibit increased life span and adipose tissue mass. Although this obese phenotype has been reported extensively for young adult male GHR-/- mice, data for females and for other ages in either gender are lacking. Thus, the purpose of this study was to evaluate body composition longitudinally in both male and female GHR-/- mice. Results show that GHR-/- mice have a greater percent fat mass with no significant difference in absolute fat mass throughout life. Lean mass shows an opposite trend with percent lean mass not significantly different between genotypes but absolute mass reduced in GHR-/- mice. Differences in body composition are more pronounced in male than in female mice, and both genders of GHR-/- mice show specific enlargement of the subcutaneous adipose depot. Along with previously published data, these results suggest a consistent and intriguing protective effect of excess fat mass in the subcutaneous region.

  19. Shocks and currents in stratified atmospheres with a magnetic null point

    Science.gov (United States)

    Tarr, Lucas A.; Linton, Mark

    2017-08-01

    We use the resistive MHD code LARE (Arber et al 2001) to inject a compressive MHD wavepacket into a stratified atmosphere that has a single magnetic null point, as recently described in Tarr et al 2017. The 2.5D simulation represents a slice through a small ephemeral region or area of plage. The strong gradients in field strength and connectivity related to the presence of the null produce substantially different dynamics compared to the more slowly varying fields typically used in simple sunspot models. The wave-null interaction produces a fast mode shock that collapses the null into a current sheet and generates a set of outward propagating (from the null) slow mode shocks confined to field lines near each separatrix. A combination of oscillatory reconnection and shock dissipation ultimately raise the plasma's internal energy at the null and along each separatrix by 25-50% above the background. The resulting pressure gradients must be balanced by Lorentz forces, so that the final state has contact discontinuities along each separatrix and a persistent current at the null. The simulation demonstrates that fast and slow mode waves localize currents to the topologically important locations of the field, just as their Alfvenic counterparts do, and also illustrates the necessity of treating waves and reconnection as coupled phenomena.

  20. Modular Hamiltonians on the null plane and the Markov property of the vacuum state

    Science.gov (United States)

    Casini, Horacio; Testé, Eduardo; Torroba, Gonzalo

    2017-09-01

    We compute the modular Hamiltonians of regions having the future horizon lying on a null plane. For a CFT this is equivalent to regions with a boundary of arbitrary shape lying on the null cone. These Hamiltonians have a local expression on the horizon formed by integrals of the stress tensor. We prove this result in two different ways, and show that the modular Hamiltonians of these regions form an infinite dimensional Lie algebra. The corresponding group of unitary transformations moves the fields on the null surface locally along the null generators with arbitrary null line dependent velocities, but act non-locally outside the null plane. We regain this result in greater generality using more abstract tools on the algebraic quantum field theory. Finally, we show that modular Hamiltonians on the null surface satisfy a Markov property that leads to the saturation of the strong sub-additive inequality for the entropies and to the strong super-additivity of the relative entropy.

  1. HBV genotypic variability in Cuba.

    Directory of Open Access Journals (Sweden)

    Carmen L Loureiro

    Full Text Available The genetic diversity of HBV in human population is often a reflection of its genetic admixture. The aim of this study was to explore the genotypic diversity of HBV in Cuba. The S genomic region of Cuban HBV isolates was sequenced and for selected isolates the complete genome or precore-core sequence was analyzed. The most frequent genotype was A (167/250, 67%, mainly A2 (149, 60% but also A1 and one A4. A total of 77 isolates were classified as genotype D (31%, with co-circulation of several subgenotypes (56 D4, 2 D1, 5 D2, 7 D3/6 and 7 D7. Three isolates belonged to genotype E, two to H and one to B3. Complete genome sequence analysis of selected isolates confirmed the phylogenetic analysis performed with the S region. Mutations or polymorphisms in precore region were more common among genotype D compared to genotype A isolates. The HBV genotypic distribution in this Caribbean island correlates with the Y lineage genetic background of the population, where a European and African origin prevails. HBV genotypes E, B3 and H isolates might represent more recent introductions.

  2. HBV Genotypic Variability in Cuba

    Science.gov (United States)

    Loureiro, Carmen L.; Aguilar, Julio C.; Aguiar, Jorge; Muzio, Verena; Pentón, Eduardo; Garcia, Daymir; Guillen, Gerardo; Pujol, Flor H.

    2015-01-01

    The genetic diversity of HBV in human population is often a reflection of its genetic admixture. The aim of this study was to explore the genotypic diversity of HBV in Cuba. The S genomic region of Cuban HBV isolates was sequenced and for selected isolates the complete genome or precore-core sequence was analyzed. The most frequent genotype was A (167/250, 67%), mainly A2 (149, 60%) but also A1 and one A4. A total of 77 isolates were classified as genotype D (31%), with co-circulation of several subgenotypes (56 D4, 2 D1, 5 D2, 7 D3/6 and 7 D7). Three isolates belonged to genotype E, two to H and one to B3. Complete genome sequence analysis of selected isolates confirmed the phylogenetic analysis performed with the S region. Mutations or polymorphisms in precore region were more common among genotype D compared to genotype A isolates. The HBV genotypic distribution in this Caribbean island correlates with the Y lineage genetic background of the population, where a European and African origin prevails. HBV genotypes E, B3 and H isolates might represent more recent introductions. PMID:25742179

  3. Magnetoacoustic Waves in a Stratified Atmosphere with a Magnetic Null Point

    Energy Technology Data Exchange (ETDEWEB)

    Tarr, Lucas A.; Linton, Mark; Leake, James, E-mail: lucas.tarr.ctr@nrl.navy.mil [U.S. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)

    2017-03-01

    We perform nonlinear MHD simulations to study the propagation of magnetoacoustic waves from the photosphere to the low corona. We focus on a 2D system with a gravitationally stratified atmosphere and three photospheric concentrations of magnetic flux that produce a magnetic null point with a magnetic dome topology. We find that a single wavepacket introduced at the lower boundary splits into multiple secondary wavepackets. A portion of the packet refracts toward the null owing to the varying Alfvén speed. Waves incident on the equipartition contour surrounding the null, where the sound and Alfvén speeds coincide, partially transmit, reflect, and mode-convert between branches of the local dispersion relation. Approximately 15.5% of the wavepacket’s initial energy ( E {sub input}) converges on the null, mostly as a fast magnetoacoustic wave. Conversion is very efficient: 70% of the energy incident on the null is converted to slow modes propagating away from the null, 7% leaves as a fast wave, and the remaining 23% (0.036 E {sub input}) is locally dissipated. The acoustic energy leaving the null is strongly concentrated along field lines near each of the null’s four separatrices. The portion of the wavepacket that refracts toward the null, and the amount of current accumulation, depends on the vertical and horizontal wavenumbers and the centroid position of the wavepacket as it crosses the photosphere. Regions that refract toward or away from the null do not simply coincide with regions of open versus closed magnetic field or regions of particular field orientation. We also model wavepacket propagation using a WKB method and find that it agrees qualitatively, though not quantitatively, with the results of the numerical simulation.

  4. An improved null model for assessing the net effects of multiple stressors on communities.

    Science.gov (United States)

    Thompson, Patrick L; MacLennan, Megan M; Vinebrooke, Rolf D

    2018-01-01

    Ecological stressors (i.e., environmental factors outside their normal range of variation) can mediate each other through their interactions, leading to unexpected combined effects on communities. Determining whether the net effect of stressors is ecologically surprising requires comparing their cumulative impact to a null model that represents the linear combination of their individual effects (i.e., an additive expectation). However, we show that standard additive and multiplicative null models that base their predictions on the effects of single stressors on community properties (e.g., species richness or biomass) do not provide this linear expectation, leading to incorrect interpretations of antagonistic and synergistic responses by communities. We present an alternative, the compositional null model, which instead bases its predictions on the effects of stressors on individual species, and then aggregates them to the community level. Simulations demonstrate the improved ability of the compositional null model to accurately provide a linear expectation of the net effect of stressors. We simulate the response of communities to paired stressors that affect species in a purely additive fashion and compare the relative abilities of the compositional null model and two standard community property null models (additive and multiplicative) to predict these linear changes in species richness and community biomass across different combinations (both positive, negative, or opposite) and intensities of stressors. The compositional model predicts the linear effects of multiple stressors under almost all scenarios, allowing for proper classification of net effects, whereas the standard null models do not. Our findings suggest that current estimates of the prevalence of ecological surprises on communities based on community property null models are unreliable, and should be improved by integrating the responses of individual species to the community level as does our

  5. Lack of mitochondrial trifunctional protein in mice causes neonatal hypoglycemia and sudden death

    OpenAIRE

    Ibdah, Jamal A.; Paul, Hyacinth; Zhao, Yiwen; Binford, Scott; Salleng, Ken; Cline, Mark; Matern, Dietrich; Bennett, Michael J.; Rinaldo, Piero; Strauss, Arnold W.

    2001-01-01

    Mitochondrial trifunctional protein (MTP) is a hetero-octamer of four α and four β subunits that catalyzes the final three steps of mitochondrial long chain fatty acid β-oxidation. Human MTP deficiency causes Reye-like syndrome, cardiomyopathy, or sudden unexpected death. We used gene targeting to generate an MTP α subunit null allele and to produce mice that lack MTP α and β subunits. The Mtpa–/– fetuses accumulate long chain fatty acid metabolites and have low birth weight compared with the...

  6. Argonaute-2-null embryonic stem cells are retarded in self-renewal ...

    Indian Academy of Sciences (India)

    Present address: Institute of Stem Cells and Regenerative Medicine, Bangalore, India ... [Chandra Shekar P, Naim A, Partha Sarathi D and Kumar S 2011 Argonaute-2-null embryonic stem cells are retarded in self-renewal ..... Research, India.

  7. Possible Solution to Publication Bias Through Bayesian Statistics, Including Proper Null Hypothesis Testing

    NARCIS (Netherlands)

    Konijn, Elly A.; van de Schoot, Rens; Winter, Sonja D.; Ferguson, Christopher J.

    2015-01-01

    The present paper argues that an important cause of publication bias resides in traditional frequentist statistics forcing binary decisions. An alternative approach through Bayesian statistics provides various degrees of support for any hypothesis allowing balanced decisions and proper null

  8. Vacuum non-expanding horizons and shear-free null geodesic congruences

    International Nuclear Information System (INIS)

    Adamo, T M; Newman, E T

    2009-01-01

    We investigate the geometry of a particular class of null surfaces in spacetime called vacuum non-expanding horizons (NEHs). Using the spin-coefficient equation, we provide a complete description of the horizon geometry, as well as fixing a canonical choice of null tetrad and coordinates on a NEH. By looking for particular classes of null geodesic congruences which live exterior to NEHs but have the special property that their shear vanishes at the intersection with the horizon, a good cut formalism for NEHs is developed which closely mirrors asymptotic theory. In particular, we show that such null geodesic congruences are generated by arbitrary choice of a complex worldline in a complex four-dimensional space, each such choice induces a CR structure on the horizon, and a particular worldline (and hence CR structure) may be chosen by transforming to a privileged tetrad frame.

  9. ON THE NATURE OF RECONNECTION AT A SOLAR CORONAL NULL POINT ABOVE A SEPARATRIX DOME

    International Nuclear Information System (INIS)

    Pontin, D. I.; Priest, E. R.; Galsgaard, K.

    2013-01-01

    Three-dimensional magnetic null points are ubiquitous in the solar corona and in any generic mixed-polarity magnetic field. We consider magnetic reconnection at an isolated coronal null point whose fan field lines form a dome structure. Using analytical and computational models, we demonstrate several features of spine-fan reconnection at such a null, including the fact that substantial magnetic flux transfer from one region of field line connectivity to another can occur. The flux transfer occurs across the current sheet that forms around the null point during spine-fan reconnection, and there is no separator present. Also, flipping of magnetic field lines takes place in a manner similar to that observed in the quasi-separatrix layer or slip-running reconnection

  10. Are eikonal quasinormal modes linked to the unstable circular null geodesics?

    Directory of Open Access Journals (Sweden)

    R.A. Konoplya

    2017-08-01

    Full Text Available In Cardoso et al. [6] it was claimed that quasinormal modes which any stationary, spherically symmetric and asymptotically flat black hole emits in the eikonal regime are determined by the parameters of the circular null geodesic: the real and imaginary parts of the quasinormal mode are multiples of the frequency and instability timescale of the circular null geodesics respectively. We shall consider asymptotically flat black hole in the Einstein–Lovelock theory, find analytical expressions for gravitational quasinormal modes in the eikonal regime and analyze the null geodesics. Comparison of the both phenomena shows that the expected link between the null geodesics and quasinormal modes is violated in the Einstein–Lovelock theory. Nevertheless, the correspondence exists for a number of other cases and here we formulate its actual limits.

  11. Are eikonal quasinormal modes linked to the unstable circular null geodesics?

    Science.gov (United States)

    Konoplya, R. A.; Stuchlík, Z.

    2017-08-01

    In Cardoso et al. [6] it was claimed that quasinormal modes which any stationary, spherically symmetric and asymptotically flat black hole emits in the eikonal regime are determined by the parameters of the circular null geodesic: the real and imaginary parts of the quasinormal mode are multiples of the frequency and instability timescale of the circular null geodesics respectively. We shall consider asymptotically flat black hole in the Einstein-Lovelock theory, find analytical expressions for gravitational quasinormal modes in the eikonal regime and analyze the null geodesics. Comparison of the both phenomena shows that the expected link between the null geodesics and quasinormal modes is violated in the Einstein-Lovelock theory. Nevertheless, the correspondence exists for a number of other cases and here we formulate its actual limits.

  12. Vlasov Fluid stability of a 2-D plasma with a linear magnetic field null

    International Nuclear Information System (INIS)

    Kim, J.S.

    1984-01-01

    Vlasov Fluid stability of a 2-dimensional plasma near an O type magnetic null is investigated. Specifically, an elongated Z-pinch is considered, and applied to Field Reversed Configurations at Los Alamos National Laboratory by making a cylindrical approximation of the compact torus. The orbits near an elliptical O type null are found to be very complicated; the orbits are large and some are stochastic. The kinetic corrections to magnetohydrodynamics (MHD) are investigated by evaluating the expectation values of the growth rates of a Vlasov Fluid dispersion functional by using a set of trial functions based on ideal MHD. The dispersion functional involves fluid parts and orbit dependent parts. The latter involves phase integral of two time correlations. The phase integral is replaced by the time integral both for the regular and for the stochastic orbits. Two trial functions are used; one has a large displacement near the null and the other away from the null

  13. Echinococcus granulosus genotypes in Iran

    Science.gov (United States)

    Sharafi, Seyedeh Maryam; Rostami-Nejad, Mohammad; Moazeni, Mohammad; Yousefi, Morteza; Saneie, Behnam; Hosseini-Safa, Ahmad

    2014-01-01

    Hydatidosis, caused by Echinococcus granulosus is one of the most important zoonotic diseases, throughout most parts of the world. Hydatidosis is endemic in Iran and responsible for approximately 1% of admission to surgical wards. There are extensive genetic variations within E. granulosus and 10 different genotypes (G1–G10) within this parasite have been reported. Identification of strains is important for improvement of control and prevention of the disease. No new review article presented the situation of Echinococcus granulosus genotypes in Iran in the recent years; therefore in this paper we reviewed the different studies regarding Echinococcus granulosus genotypes in Iran. PMID:24834298

  14. Hypersensitivities for acetaldehyde and other agents among cancer cells null for clinically relevant Fanconi anemia genes.

    Science.gov (United States)

    Ghosh, Soma; Sur, Surojit; Yerram, Sashidhar R; Rago, Carlo; Bhunia, Anil K; Hossain, M Zulfiquer; Paun, Bogdan C; Ren, Yunzhao R; Iacobuzio-Donahue, Christine A; Azad, Nilofer A; Kern, Scott E

    2014-01-01

    Large-magnitude numerical distinctions (>10-fold) among drug responses of genetically contrasting cancers were crucial for guiding the development of some targeted therapies. Similar strategies brought epidemiological clues and prevention goals for genetic diseases. Such numerical guides, however, were incomplete or low magnitude for Fanconi anemia pathway (FANC) gene mutations relevant to cancer in FANC-mutation carriers (heterozygotes). We generated a four-gene FANC-null cancer panel, including the engineering of new PALB2/FANCN-null cancer cells by homologous recombination. A characteristic matching of FANCC-null, FANCG-null, BRCA2/FANCD1-null, and PALB2/FANCN-null phenotypes was confirmed by uniform tumor regression on single-dose cross-linker therapy in mice and by shared chemical hypersensitivities to various inter-strand cross-linking agents and γ-radiation in vitro. Some compounds, however, had contrasting magnitudes of sensitivity; a strikingly high (19- to 22-fold) hypersensitivity was seen among PALB2-null and BRCA2-null cells for the ethanol metabolite, acetaldehyde, associated with widespread chromosomal breakage at a concentration not producing breaks in parental cells. Because FANC-defective cancer cells can share or differ in their chemical sensitivities, patterns of selective hypersensitivity hold implications for the evolutionary understanding of this pathway. Clinical decisions for cancer-relevant prevention and management of FANC-mutation carriers could be modified by expanded studies of high-magnitude sensitivities. Copyright © 2014 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  15. Identification of zoonotic genotypes of Giardia duodenalis.

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    Hein Sprong

    Full Text Available Giardia duodenalis, originally regarded as a commensal organism, is the etiologic agent of giardiasis, a gastrointestinal disease of humans and animals. Giardiasis causes major public and veterinary health concerns worldwide. Transmission is either direct, through the faecal-oral route, or indirect, through ingestion of contaminated water or food. Genetic characterization of G. duodenalis isolates has revealed the existence of seven groups (assemblages A to G which differ in their host distribution. Assemblages A and B are found in humans and in many other mammals, but the role of animals in the epidemiology of human infection is still unclear, despite the fact that the zoonotic potential of Giardia was recognised by the WHO some 30 years ago. Here, we performed an extensive genetic characterization of 978 human and 1440 animal isolates, which together comprise 3886 sequences from 4 genetic loci. The data were assembled into a molecular epidemiological database developed by a European network of public and veterinary health Institutions. Genotyping was performed at different levels of resolution (single and multiple loci on the same dataset. The zoonotic potential of both assemblages A and B is evident when studied at the level of assemblages, sub-assemblages, and even at each single locus. However, when genotypes are defined using a multi-locus sequence typing scheme, only 2 multi-locus genotypes (MLG of assemblage A and none of assemblage B appear to have a zoonotic potential. Surprisingly, mixtures of genotypes in individual isolates were repeatedly observed. Possible explanations are the uptake of genetically different Giardia cysts by a host, or subsequent infection of an already infected host, likely without overt symptoms, with a different Giardia species, which may cause disease. Other explanations for mixed genotypes, particularly for assemblage B, are substantial allelic sequence heterogeneity and/or genetic recombination. Although the

  16. Null geodesics and embedding diagrams of the interior Schwarzschild--de Sitter spacetimes with uniform density

    International Nuclear Information System (INIS)

    Stuchlik, Zdenek; Hledik, Stanislav; Soltes, Jiri; Ostgaard, Erlend

    2001-01-01

    Null geodesics and embedding diagrams of central planes in the ordinary space geometry and the optical reference geometry of the interior Schwarzschild--de Sitter spacetimes with uniform density are studied. For completeness, both positive and negative values of the cosmological constant are considered. The null geodesics are restricted to the central planes of these spacetimes, and their properties can be reflected by an 'effective potential.' If the interior spacetime is extremely compact, the effective potential has a local maximum corresponding to a stable circular null geodesic around which bound null geodesics are concentrated. The upper limit on the size of the interior spacetimes containing bound null geodesics is R=3M, independently of the value of the cosmological constant. The embedding diagrams of the central planes of the ordinary geometry into three-dimensional Euclidean space are well defined for the complete interior of all spacetimes with a repulsive cosmological constant, but the planes cannot be embedded into the Euclidean space in the case of spacetimes with subcritical values of an attractive cosmological constant. On the other hand, the embedding diagrams of the optical geometry are well defined for all of the spacetimes, and the turning points of these diagrams correspond to the radii of the circular null geodesics. All the embedding diagrams, for both the ordinary and optical geometry, are smoothly matched to the corresponding embedding diagrams of the external vacuum Schwarzschild--de Sitter spacetimes

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

    Science.gov (United States)

    White, J.; Brakefield, L. K.

    2015-12-01

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

  18. The data-driven null models for information dissemination tree in social networks

    Science.gov (United States)

    Zhang, Zhiwei; Wang, Zhenyu

    2017-10-01

    For the purpose of detecting relatedness and co-occurrence between users, as well as the distribution features of nodes in spreading path of a social network, this paper explores topological characteristics of information dissemination trees (IDT) that can be employed indirectly to probe the information dissemination laws within social networks. Hence, three different null models of IDT are presented in this article, including the statistical-constrained 0-order IDT null model, the random-rewire-broken-edge 0-order IDT null model and the random-rewire-broken-edge 2-order IDT null model. These null models firstly generate the corresponding randomized copy of an actual IDT; then the extended significance profile, which is developed by adding the cascade ratio of information dissemination path, is exploited not only to evaluate degree correlation of two nodes associated with an edge, but also to assess the cascade ratio of different length of information dissemination paths. The experimental correspondences of the empirical analysis for several SinaWeibo IDTs and Twitter IDTs indicate that the IDT null models presented in this paper perform well in terms of degree correlation of nodes and dissemination path cascade ratio, which can be better to reveal the features of information dissemination and to fit the situation of real social networks.

  19. Losses at magnetic nulls in pulsed-power transmission line systems

    International Nuclear Information System (INIS)

    Mendel, C.W. Jr.; Pointon, T.D.; Savage, M.E.; Seidel, D.B.; Magne, I.; Vezinet, R.

    2006-01-01

    Pulsed-power systems operating in the terawatt regime must deal with large electron flows in vacuum transmission lines. In most parts of these transmission lines the electrons are constrained by the self-magnetic field to flow parallel to the conductors. In very low impedance systems, such as those used to drive Z-pinch radiation sources, the currents from multiple transmission lines are added together. This addition necessarily involves magnetic nulls that connect the positive and negative electrodes. The resultant local loss of magnetic insulation results in electron losses at the anode in the vicinity of the nulls. The lost current due to the magnetic null might or might not be appreciable. In some cases the lost current due to the null is not large, but is spatially localized, and may create a gas and plasma release from the anode that can lead to an excessive loss, and possibly to catastrophic damage to the hardware. In this paper we describe an analytic model that uses one geometric parameter (aside from straightforward hardware size measurements) that determines the loss to the anode, and the extent of the loss region when the driving source and load are known. The parameter can be calculated in terms of the magnetic field in the region of the null calculated when no electron flow is present. The model is compared to some experimental data, and to simulations of several different hardware geometries, including some cases with multiple nulls, and unbalanced feeds

  20. Premeiotic germ cell defect in seminiferous tubules of Atm-null testis

    International Nuclear Information System (INIS)

    Takubo, Keiyo; Hirao, Atsushi; Ohmura, Masako; Azuma, Masaki; Arai, Fumio; Nagamatsu, Go; Suda, Toshio

    2006-01-01

    Lifelong spermatogenesis is maintained by coordinated sequential processes including self-renewal of stem cells, proliferation of spermatogonial cells, meiotic division, and spermiogenesis. It has been shown that ataxia telangiectasia-mutated (ATM) is required for meiotic division of the seminiferous tubules. Here, we show that, in addition to its role in meiosis, ATM has a pivotal role in premeiotic germ cell maintenance. ATM is activated in premeiotic spermatogonial cells and the Atm-null testis shows progressive degeneration. In Atm-null testicular cells, differing from bone marrow cells of Atm-null mice, reactive oxygen species-mediated p16 Ink4a activation does not occur in Atm-null premeiotic germ cells, which suggests the involvement of different signaling pathways from bone marrow defects. Although Atm-null bone marrow undergoes p16 Ink4a -mediated cellular senescence program, Atm-null premeiotic germ cells exhibited cell cycle arrest and apoptotic elimination of premeiotic germ cells, which is different from p16 Ink4a -mediated senescence

  1. Aquaglyceroporin-null trypanosomes display glycerol transport defects and respiratory-inhibitor sensitivity.

    Directory of Open Access Journals (Sweden)

    Laura Jeacock

    2017-03-01

    Full Text Available Aquaglyceroporins (AQPs transport water and glycerol and play important roles in drug-uptake in pathogenic trypanosomatids. For example, AQP2 in the human-infectious African trypanosome, Trypanosoma brucei gambiense, is responsible for melarsoprol and pentamidine-uptake, and melarsoprol treatment-failure has been found to be due to AQP2-defects in these parasites. To further probe the roles of these transporters, we assembled a T. b. brucei strain lacking all three AQP-genes. Triple-null aqp1-2-3 T. b. brucei displayed only a very moderate growth defect in vitro, established infections in mice and recovered effectively from hypotonic-shock. The aqp1-2-3 trypanosomes did, however, display glycerol uptake and efflux defects. They failed to accumulate glycerol or to utilise glycerol as a carbon-source and displayed increased sensitivity to salicylhydroxamic acid (SHAM, octyl gallate or propyl gallate; these inhibitors of trypanosome alternative oxidase (TAO can increase intracellular glycerol to toxic levels. Notably, disruption of AQP2 alone generated cells with glycerol transport defects. Consistent with these findings, AQP2-defective, melarsoprol-resistant clinical isolates were sensitive to the TAO inhibitors, SHAM, propyl gallate and ascofuranone, relative to melarsoprol-sensitive reference strains. We conclude that African trypanosome AQPs are dispensable for viability and osmoregulation but they make important contributions to drug-uptake, glycerol-transport and respiratory-inhibitor sensitivity. We also discuss how the AQP-dependent inverse sensitivity to melarsoprol and respiratory inhibitors described here might be exploited.

  2. Long-term improvements in sensory inhibition with gestational choline supplementation linked to α7 nicotinic receptors through studies in Chrna7 null mutation mice.

    Science.gov (United States)

    Stevens, Karen E; Choo, Kevin S; Stitzel, Jerry A; Marks, Michael J; Adams, Catherine E

    2014-03-13

    Perinatal choline supplementation has produced several benefits in rodent models, from improved learning and memory to protection from the behavioral effects of fetal alcohol exposure. We have shown that supplemented choline through gestation and lactation produces long-term improvement in deficient sensory inhibition in DBA/2 mice which models a similar deficit in schizophrenia patients. The present study extends that research by feeding normal or supplemented choline diets to DBA/2 mice carrying the null mutation for the α7 nicotinic receptor gene (Chrna7). DBA/2 mice heterozygotic for Chrna7 were bred together. Dams were placed on supplemented (5 gm/kg diet) or normal (1.1 gm/kg diet) choline at mating and remained on the specific diet until offspring weaning. Thereafter, offspring were fed standard rodent chow. Adult offspring were assessed for sensory inhibition. Brains were obtained to ascertain hippocampal α7 nicotinic receptor levels. Choline-supplemented mice heterozygotic or null-mutant for Chrna7 failed to show improvement in sensory inhibition. Only wildtype choline-supplemented mice showed improvement with the effect solely through a decrease in test amplitude. This supports the hypothesis that gestational-choline supplementation is acting through the α7 nicotinic receptor to improve sensory inhibition. Although there was a significant gene-dose-related change in hippocampal α7 receptor numbers, binding studies did not reveal any choline-dose-related change in binding in any hippocampal region, the interaction being driven by a significant genotype main effect (wildtype>heterozygote>null mutant). These data parallel a human study wherein the offspring of pregnant women receiving choline supplementation during gestation, showed better sensory inhibition than offspring of women on placebo. Published by Elsevier B.V.

  3. BK polyomavirus genotypes Ia and Ib1 exhibit different biological properties in renal transplant recipients.

    Science.gov (United States)

    Varella, Rafael B; Zalona, Ana Carolina J; Diaz, Nuria C; Zalis, Mariano G; Santoro-Lopes, Guilherme

    2018-01-02

    BK polyomavirus (BKV) is an opportunist agent associated with nephropathy (BKVAN) in 1-10% of kidney transplant recipients. BKV is classified into genotypes or subgroups according to minor nucleotidic variations with unknown biological implications. Studies assessing the possible association between genotypes and the risk of BKVAN in kidney transplant patients have presented conflicting results. In these studies, genotype Ia, which is highly prevalent in Brazil, was less frequently found and, thus, comparative data on the biological properties of this genotype are lacking. In this study, BKV Ia and Ib1 genotypes were compared according to their viral load, genetic evolution (VP1 and NCCR) - in a cohort of renal transplant recipients. The patients infected with Ia (13/23; 56.5%) genotype exhibited higher viral loads in urine [>1.4 log over Ib1 (10/23; 43.5%); p=0.025]. In addition, genotype Ia was associated with diverse mutations at VP1 loops and sites under positive selection outside loops, which were totally absent in Ib1. Although the number of viremic patients was similar, the three patients who had BK nephropathy (BKVAN) were infected with Ia genotype. NCCR architecture (ww or rr) were not distinctive between Ia and Ib1 genotypes. Ia genotype, which is rare in other published BKV cohorts, presented some diverse biological properties in transplanted recipients in comparison to Ib1. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. S-phase checkpoint elements of the E2F-1 family increase radiosensitivity in fibrosarcoma cells lacking p53

    International Nuclear Information System (INIS)

    Bodis, Stephan; Pruschy, Martin; Wirbelauer, Christiane; Glanzmann, Christoph; Krek, Wilhelm

    1997-01-01

    Purpose: Correct advance of cells through the S-phase of the mammalian cell cycle depends on the timely controlled activity of the E2F-1 transcription factor by cyclin A-cdk2. We are studying the reproductive integrity and radiosensitation of isogenic mouse fibrosarcoma cells, differing only in their p53 status, after expression of E2F-1 wildtype (wt) and specific E2F-1 mutants (mt) lacking the cyclin-A-binding domain. In this tumor model system only p53 wild-type expressing tumor cells are sensitive to ionizing radiation in vitro and in vivo. Material and Methods: Either wild-type p53 or genetically engineered p53 'null' mouse embryo fibroblasts were transfected with the oncogenes E1A and ras. These otherwise isogenic fibrosarcoma cells, with a malignant phenotype and tumorigenic in nude mice, were transfected with retroviruses containing either E2F-1 wild-type or specific E2F-1 mutants lacking the cyclin-A binding domain. Reproductive integrity after E2F-1 transfection with or without ionizing radiation (RT) was tested using the clonogenic assay. Tumor cell morphology of treated cells is analyzed for cell death mechanism. Results: E2F-1 wild-type expression in fibrosarcoma cells induced a clear p53 dependent cell death. While clonogenic survival of p53 'null' tumor cells was only slightly reduced with the expression of E2F-1 wild type (survival fraction of 0.5), the clonogenic survival of p53 wild-type fibrosarcoma tumor cells was reduced by at least one logarithm (survival fraction of 0.05). However, expression of the specific E2F-1 mutant lacking the cyclin-A binding domain reduced clonogenic survival in both the p53 'null' and the p53 wild-type fibrosarcoma cells by at least 2 logarithms (survival fraction 0.01 for p53 'null' and 0.002 for p53 wild-type). The mean values of the survival fractions after 2 and 5 Gy radiation alone in p53 'null' fibrosarcoma cells (SF 2 and SF 5) were SF 2 0.7, SF 5 = 0.15, respectively. The combination of ionizing RT in the p53

  5. Efficient generation of GGTA1-null Diannan miniature pigs using TALENs combined with somatic cell nuclear transfer

    Directory of Open Access Journals (Sweden)

    Wenmin Cheng

    2016-11-01

    after 33 d of gestation for genotyping. In total, 12 live and two stillborn piglets were collected from six surrogates by either caesarean or natural birth. Sequencing analyses of the target site confirmed the homozygous GGTA1-null mutation in all fetuses and piglets, consistent with the genotype of the donor cells. Furthermore, FACS, confocal microscopy, IHC and western blotting analyses demonstrated that Gal epitopes were completely absent from the fibroblasts, kidneys and pancreas of one GTKO piglet. Conclusions TALENs combined with SCNT were successfully used to generate GTKO Diannan miniature piglets.

  6. Transforming microbial genotyping: a robotic pipeline for genotyping bacterial strains.

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    Brian O'Farrell

    Full Text Available Microbial genotyping increasingly deals with large numbers of samples, and data are commonly evaluated by unstructured approaches, such as spread-sheets. The efficiency, reliability and throughput of genotyping would benefit from the automation of manual manipulations within the context of sophisticated data storage. We developed a medium- throughput genotyping pipeline for MultiLocus Sequence Typing (MLST of bacterial pathogens. This pipeline was implemented through a combination of four automated liquid handling systems, a Laboratory Information Management System (LIMS consisting of a variety of dedicated commercial operating systems and programs, including a Sample Management System, plus numerous Python scripts. All tubes and microwell racks were bar-coded and their locations and status were recorded in the LIMS. We also created a hierarchical set of items that could be used to represent bacterial species, their products and experiments. The LIMS allowed reliable, semi-automated, traceable bacterial genotyping from initial single colony isolation and sub-cultivation through DNA extraction and normalization to PCRs, sequencing and MLST sequence trace evaluation. We also describe robotic sequencing to facilitate cherrypicking of sequence dropouts. This pipeline is user-friendly, with a throughput of 96 strains within 10 working days at a total cost of 200,000 items were processed by two to three people. Our sophisticated automated pipeline can be implemented by a small microbiology group without extensive external support, and provides a general framework for semi-automated bacterial genotyping of large numbers of samples at low cost.

  7. Influence of choice of null network on small-world parameters of structural correlation networks.

    Directory of Open Access Journals (Sweden)

    S M Hadi Hosseini

    Full Text Available In recent years, coordinated variations in brain morphology (e.g., volume, thickness have been employed as a measure of structural association between brain regions to infer large-scale structural correlation networks. Recent evidence suggests that brain networks constructed in this manner are inherently more clustered than random networks of the same size and degree. Thus, null networks constructed by randomizing topology are not a good choice for benchmarking small-world parameters of these networks. In the present report, we investigated the influence of choice of null networks on small-world parameters of gray matter correlation networks in healthy individuals and survivors of acute lymphoblastic leukemia. Three types of null networks were studied: 1 networks constructed by topology randomization (TOP, 2 networks matched to the distributional properties of the observed covariance matrix (HQS, and 3 networks generated from correlation of randomized input data (COR. The results revealed that the choice of null network not only influences the estimated small-world parameters, it also influences the results of between-group differences in small-world parameters. In addition, at higher network densities, the choice of null network influences the direction of group differences in network measures. Our data suggest that the choice of null network is quite crucial for interpretation of group differences in small-world parameters of structural correlation networks. We argue that none of the available null models is perfect for estimation of small-world parameters for correlation networks and the relative strengths and weaknesses of the selected model should be carefully considered with respect to obtained network measures.

  8. Influence of Choice of Null Network on Small-World Parameters of Structural Correlation Networks

    Science.gov (United States)

    Hosseini, S. M. Hadi; Kesler, Shelli R.

    2013-01-01

    In recent years, coordinated variations in brain morphology (e.g., volume, thickness) have been employed as a measure of structural association between brain regions to infer large-scale structural correlation networks. Recent evidence suggests that brain networks constructed in this manner are inherently more clustered than random networks of the same size and degree. Thus, null networks constructed by randomizing topology are not a good choice for benchmarking small-world parameters of these networks. In the present report, we investigated the influence of choice of null networks on small-world parameters of gray matter correlation networks in healthy individuals and survivors of acute lymphoblastic leukemia. Three types of null networks were studied: 1) networks constructed by topology randomization (TOP), 2) networks matched to the distributional properties of the observed covariance matrix (HQS), and 3) networks generated from correlation of randomized input data (COR). The results revealed that the choice of null network not only influences the estimated small-world parameters, it also influences the results of between-group differences in small-world parameters. In addition, at higher network densities, the choice of null network influences the direction of group differences in network measures. Our data suggest that the choice of null network is quite crucial for interpretation of group differences in small-world parameters of structural correlation networks. We argue that none of the available null models is perfect for estimation of small-world parameters for correlation networks and the relative strengths and weaknesses of the selected model should be carefully considered with respect to obtained network measures. PMID:23840672

  9. Abnormal Activation of BMP Signaling Causes Myopathy in Fbn2 Null Mice.

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    Gerhard Sengle

    2015-06-01

    Full Text Available Fibrillins are large extracellular macromolecules that polymerize to form the backbone structure of connective tissue microfibrils. Mutations in the gene for fibrillin-1 cause the Marfan syndrome, while mutations in the gene for fibrillin-2 cause Congenital Contractural Arachnodactyly. Both are autosomal dominant disorders, and both disorders affect musculoskeletal tissues. Here we show that Fbn2 null mice (on a 129/Sv background are born with reduced muscle mass, abnormal muscle histology, and signs of activated BMP signaling in skeletal muscle. A delay in Myosin Heavy Chain 8, a perinatal myosin, was found in Fbn2 null forelimb muscle tissue, consistent with the notion that muscle defects underlie forelimb contractures in these mice. In addition, white fat accumulated in the forelimbs during the early postnatal period. Adult Fbn2 null mice are already known to demonstrate persistent muscle weakness. Here we measured elevated creatine kinase levels in adult Fbn2 null mice, indicating ongoing cycles of muscle injury. On a C57Bl/6 background, Fbn2 null mice showed severe defects in musculature, leading to neonatal death from respiratory failure. These new findings demonstrate that loss of fibrillin-2 results in phenotypes similar to those found in congenital muscular dystrophies and that FBN2 should be considered as a candidate gene for recessive congenital muscular dystrophy. Both in vivo and in vitro evidence associated muscle abnormalities and accumulation of white fat in Fbn2 null mice with abnormally activated BMP signaling. Genetic rescue of reduced muscle mass and accumulation of white fat in Fbn2 null mice was accomplished by deleting a single allele of Bmp7. In contrast to other reports that activated BMP signaling leads to muscle hypertrophy, our findings demonstrate the exquisite sensitivity of BMP signaling to the fibrillin-2 extracellular environment during early postnatal muscle development. New evidence presented here suggests that

  10. Averaged null energy condition and difference inequalities in quantum field theory

    International Nuclear Information System (INIS)

    Yurtsever, U.

    1995-01-01

    For a large class of quantum states, all local (pointwise) energy conditions widely used in relativity are violated by the renormalized stress-energy tensor of a quantum field. In contrast, certain nonlocal positivity constraints on the quantum stress-energy tensor might hold quite generally, and this possibility has received considerable attention in recent years. In particular, it is now known that the averaged null energy condition, the condition that the null-null component of the stress-energy tensor integrated along a complete null geodesic is non-negative for all states, holds quite generally in a wide class of spacetimes for a minimally coupled scalar field. Apart from the specific class of spacetimes considered (mainly two-dimensional spacetimes and four-dimensional Minkowski space), the most significant restriction on this result is that the null geodesic over which the average is taken must be achronal. Recently, Ford and Roman have explored this restriction in two-dimensional flat spacetime, and discovered that in a flat cylindrical space, although the stress energy tensor itself fails to satisfy the averaged null energy condition (ANEC) along the (nonachronal) null geodesics, when the ''Casimir-vacuum'' contribution is subtracted from the stress-energy the resulting tensor does satisfy the ANEC inequality. Ford and Roman name this class of constraints on the quantum stress-energy tensor ''difference inequalities.'' Here I give a proof of the difference inequality for a minimally coupled massless scalar field in an arbitrary (globally hyperbolic) two-dimensional spacetime, using the same techniques as those we relied on to prove the ANEC in an earlier paper with Wald. I begin with an overview of averaged energy conditions in quantum field theory

  11. In vitro screening of potato genotypes for osmotic stress tolerance

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    Gelmesa Dandena

    2017-02-01

    Full Text Available Potato (Solanum tuberosum L. is a cool season crop which is susceptible to both drought and heat stresses. Lack of suitable varieties of the crop adapted to drought-prone areas of the lowland tropics deprives farmers living in such areas the opportunity to produce and use the crop as a source of food and income. As a step towards developing such varieties, the present research was conducted to evaluate different potato genotypes for osmotic stress tolerance under in vitro conditions and identify drought tolerant genotypes for future field evaluation. The experiment was carried out at the Leibniz University of Hannover, Germany, by inducing osmotic stress using sorbitol at two concentrations (0.1 and 0.2 M in the culture medium. A total of 43 genotypes collected from different sources (27 advanced clones from CIP, nine improved varieties, and seven farmers’ cultivars were used in a completely randomized design with four replications in two rounds. Data were collected on root and shoot growth. The results revealed that the main effects of genotype, sorbitol treatment, and their interactions significantly (P < 0.01 influenced root and shoot growthrelated traits. Under osmotic stress, all the measured root and shoot growth traits were significantly correlated. The dendrogram obtained from the unweighted pair group method with arithmetic mean allowed grouping of the genotypes into tolerant, moderately tolerant, and susceptible ones to a sorbitol concentration of 0.2 M in the culture medium. Five advanced clones (CIP304350.100, CIP304405.47, CIP392745.7, CIP388676.1, and CIP388615.22 produced shoots and rooted earlier than all other genotypes, with higher root numbers, root length, shoot and root mass under osmotic stress conditions induced by sorbitol. Some of these genotypes had been previously identified as drought-tolerant under field conditions, suggesting the capacity of the in vitro evaluation method to predict drought stress tolerant

  12. Carrageenan-Induced Colonic Inflammation Is Reduced in Bcl10 Null Mice and Increased in IL-10-Deficient Mice

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    Sumit Bhattacharyya

    2013-01-01

    Full Text Available The common food additive carrageenan is a known activator of inflammation in mammalian tissues and stimulates both the canonical and noncanonical pathways of NF-κB activation. Exposure to low concentrations of carrageenan (10 μg/mL in the water supply has produced glucose intolerance, insulin resistance, and impaired insulin signaling in C57BL/6 mice. B-cell leukemia/lymphoma 10 (Bcl10 is a mediator of inflammatory signals from Toll-like receptor (TLR 4 in myeloid and epithelial cells. Since the TLR4 signaling pathway is activated in diabetes and by carrageenan, we addressed systemic and intestinal inflammatory responses following carrageenan exposure in Bcl10 wild type, heterozygous, and null mice. Fecal calprotectin and circulating keratinocyte chemokine (KC, nuclear RelA and RelB, phospho(Thr559-NF-κB-inducing kinase (NIK, and phospho(Ser36-IκBα in the colonic epithelial cells were significantly less (P<0.001 in the carrageenan-treated Bcl10 null mice than in controls. IL-10-deficient mice exposed to carrageenan in a germ-free environment showed an increase in activation of the canonical pathway of NF-κB (RelA activation, but without increase in RelB or phospho-Bcl10, and exogenous IL-10 inhibited only the canonical pathway of NF-κB activation in cultured colonic cells. These findings demonstrate a Bcl10 requirement for maximum development of carrageenan-induced inflammation and lack of complete suppression by IL-10 of carrageenan-induced inflammation.

  13. Zero-inflated beta regression model for leaf citrus canker incidence in orange genotypes grafted onto different rootstocks

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    Oilson Alberto Gonzatto Junior

    2017-06-01

    Full Text Available Data with excess zeros are frequently found in practice, and the recommended analysis is to use models that adequately address the counting of zero observations. In this study, the Zero Inflated Beta Regression Model (BeZI was used on experimental data to describe the mean incidence of leaf citrus canker in orange groves under the influence of genotype and rootstocks of origin. Based on the model, it was possible to quantify the odds that a null observation to mean incidence comes from a particular plant according to genotype and rootstock, and estimate its expected value according to this combination. Laranja Caipira rootstock proved to be the most resistant to leaf citrus canker as well as Limão Cravo proved to be the most fragile. The Ipiguá IAC, Arapongas, EEL and Olímpia genotypes have statistically equivalent chances.

  14. Comparative metabolism of methacrylonitrile and acrylonitrile to cyanide using cytochrome P4502E1 and microsomal epoxide hydrolase-null mice

    International Nuclear Information System (INIS)

    El Hadri, L.; Chanas, B.; Ghanayem, B.I.

    2005-01-01

    Methacrylonitrile (MAN) and acrylonitrile (AN) are metabolized via glutathione (GSH) conjugation or epoxide formation. We have recently shown that CYP2E1 is essential for AN epoxidation and subsequent cyanide liberation. Current studies were designed to compare the enzymatic basis of MAN vs. AN metabolism to cyanide using wild-type (WT), CYP2E1-, and mEH-null mice. Mice received a single gavage dose of 0.047, 0.095, 0.19, or 0.38 mmol/kg of MAN or AN, and blood cyanide was measured at 1 or 3 h later. Blood cyanide levels in WT mice treated with AN or MAN were dose and time dependent. At equimolar doses, significantly higher levels of cyanide were detected in the blood of MAN- vs. AN-treated mice. Further, while significant reduction in blood cyanide levels occurred in MAN-treated CYP2E1-null vs. WT mice, AN metabolism to cyanide was largely abolished in CYP2E1-null mice. Pretreatment of mice with 1-aminobenzotriazole (ABT, CYP inhibitor) demonstrated that CYPs other than CYP2E1 also contribute to MAN metabolism to cyanide. Blood cyanide levels in mEH-null mice treated with aliphatic nitriles are generally lower than levels in similarly treated WT mice. Western blot analysis showed that expression of sEH was greater in male vs. female mice. The role of various epoxide hydrolases (EHs) in the production of cyanide from aliphatic nitriles is apparently structure and dose dependent. Regardless of genotype, significantly higher levels of cyanide were measured in the blood of male vs. female mice treated with MAN or AN. In conclusion, these data showed that (1) at equimolar doses, higher blood cyanide levels were detected in mice treated with MAN vs. AN; (2) while CYP2E1 is the only enzyme responsible for AN metabolism to cyanide, other CYPs also contribute to MAN metabolism; and (3) significantly higher levels of cyanide were measured in the blood of male vs. female treated with either nitrile. Higher blood cyanide levels in male vs. female mice and in MAN- vs. AN

  15. Vacuum Nuller Testbed (VNT) Performance, Characterization and Null Control: Progress Report

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.; Noecker, M. Charley; Kendrick, Stephen; Helmbrecht, Michael

    2011-01-01

    Herein we report on the development. sensing and control and our first results with the Vacuum Nuller Testbed to realize a Visible Nulling Coronagraph (VNC) for exoplanet coronagraphy. The VNC is one of the few approaches that works with filled. segmented and sparse or diluted-aperture telescope systems. It thus spans a range of potential future NASA telescopes and could be Hown as a separate instrument on such a future mission. NASA/Goddard Space Flight Center (GSFC) has a well-established effort to develop VNC technologies. and has developed an incremental sequence of VNC testbeds to advance this approach and the enabling technologies associated with it. We discuss the continued development of the vacuum Visible Nulling Coronagraph testbed (VNT). Tbe VNT is an ultra-stable vibration isolated testbed that operates under closed-loop control within a vacuum chamber. It will be used to achieve an incremental sequence of three visible-light nulling milestones with sequentially higher contrasts of 10(sup 8), 10(sup 9) and ideally 10(sup 10) at an inner working angle of 2*lambda/D. The VNT is based on a modified Mach-Zehnder nulling interferometer, with a "W" configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. We discuss the initial laboratory results, the optical configuration, critical technologies and the null sensing and control approach.

  16. A Null Space Control of Two Wheels Driven Mobile Manipulator Using Passivity Theory

    Science.gov (United States)

    Shibata, Tsuyoshi; Murakami, Toshiyuki

    This paper describes a control strategy of null space motion of a two wheels driven mobile manipulator. Recently, robot is utilized in various industrial fields and it is preferable for the robot manipulator to have multiple degrees of freedom motion. Several studies of kinematics for null space motion have been proposed. However stability analysis of null space motion is not enough. Furthermore, these approaches apply to stable systems, but they do not apply unstable systems. Then, in this research, base of manipulator equips with two wheels driven mobile robot. This robot is called two wheels driven mobile manipulator, which becomes unstable system. In the proposed approach, a control design of null space uses passivity based stabilizing. A proposed controller is decided so that closed-loop system of robot dynamics satisfies passivity. This is passivity based control. Then, control strategy is that stabilizing of the robot system applies to work space observer based approach and null space control while keeping end-effector position. The validity of the proposed approach is verified by simulations and experiments of two wheels driven mobile manipulator.

  17. Time asymmetric spacetimes near null and spatial infinity: I. Expansions of developments of conformally flat data

    International Nuclear Information System (INIS)

    Kroon, Juan Antonio Valiente

    2004-01-01

    The conformal Einstein equations and the representation of spatial infinity as a cylinder introduced by Friedrich are used to analyse the behaviour of the gravitational field near null and spatial infinity for the development of data which are asymptotically Euclidean, conformally flat and time asymmetric. Our analysis allows for initial data whose second fundamental form is more general than the one given by the standard Bowen-York ansatz. The conformal Einstein equations imply, upon evaluation on the cylinder at spatial infinity, a hierarchy of transport equations which can be used to calculate asymptotic expansions for the gravitational field in a recursive way. It is found that the solutions to these transport equations develop logarithmic divergences at the critical sets where null infinity meets spatial infinity. Associated with these, there is a series of quantities expressible in terms of the initial data (obstructions), which if zero, preclude the appearance of some of the logarithmic divergences. The obstructions are, in general, time asymmetric. That is, the obstructions at the intersection of future null infinity with spatial infinity are in general different from those obtained at the intersection of past null infinity with spatial infinity. The latter allows for the possibility of having spacetimes where future and past null infinity have different degrees of smoothness. Finally, it is shown that if both sets of obstructions vanish up to a certain order, then the initial data have to be asymptotically Schwarzschildean in a certain sense

  18. Vacuum nuller testbed (VNT) performance, characterization and null control: progress report

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.; Noecker, M. Charley; Kendrick, Stephen; Helmbrecht, Michael

    2011-10-01

    Herein we report on the development, sensing and control and our first results with the Vacuum Nuller Testbed to realize a Visible Nulling Coronagraph (VNC) for exoplanet coronagraphy. The VNC is one of the few approaches that works with filled, segmented and sparse or diluted-aperture telescope systems. It thus spans a range of potential future NASA telescopes and could be flown as a separate instrument on such a future mission. NASA/Goddard Space Flight Center (GSFC) has a well-established effort to develop VNC technologies, and has developed an incremental sequence of VNC testbeds to advance this approach and the enabling technologies associated with it. We discuss the continued development of the vacuum Visible Nulling Coronagraph testbed (VNT). The VNT is an ultra-stable vibration isolated testbed that operates under closed-loop control within a vacuum chamber. It will be used to achieve an incremental sequence of three visible-light nulling milestones with sequentially higher contrasts of 108, 109, and ideally 1010 at an inner working angle of 2*λ/D. The VNT is based on a modified Mach-Zehnder nulling interferometer, with a "W" configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. We discuss the initial laboratory results, the optical configuration, critical technologies and the null sensing and control approach.

  19. Current singularities at finitely compressible three-dimensional magnetic null points

    International Nuclear Information System (INIS)

    Pontin, D.I.; Craig, I.J.D.

    2005-01-01

    The formation of current singularities at line-tied two- and three-dimensional (2D and 3D, respectively) magnetic null points in a nonresistive magnetohydrodynamic environment is explored. It is shown that, despite the different separatrix structures of 2D and 3D null points, current singularities may be initiated in a formally equivalent manner. This is true no matter whether the collapse is triggered by flux imbalance within closed, line-tied null points or driven by externally imposed velocity fields in open, incompressible geometries. A Lagrangian numerical code is used to investigate the finite amplitude perturbations that lead to singular current sheets in collapsing 2D and 3D null points. The form of the singular current distribution is analyzed as a function of the spatial anisotropy of the null point, and the effects of finite gas pressure are quantified. It is pointed out that the pressure force, while never stopping the formation of the singularity, significantly alters the morphology of the current distribution as well as dramatically weakening its strength. The impact of these findings on 2D and 3D magnetic reconnection models is discussed

  20. Anti-optic-null medium: Achieving the optic-null medium effect by enclosing an air region with relatively low-anisotropy media

    Science.gov (United States)

    Sun, Fei; Liu, Yichao; He, Sailing

    2016-07-01

    A so-called anti-optic-null medium (anti-ONM), which can be utilized to cancel the optic-null medium (ONM) and create many novel optical illusions, is introduced and designed by transformation optics (TO). Optical separation illusions can be achieved with an anti-ONM. With the help of the anti-ONM, we can achieve the same optical illusions where ONM is required via a shelled structure filled with low anisotropic medium, which is easier to realize for some novel optical devices designed by TO and optical surface transformation. The special function of the anti-ONM will lead to a new way to design optical devices or simplify the material requirements. Overlapping illusions, and wave-front reshapers are designed to demonstrate the function of the proposed method.

  1. Spectratyping analysis of the islet-reactive T cell repertoire in diabetic NOD Igμnull mice after polyclonal B cell reconstitution

    Directory of Open Access Journals (Sweden)

    Sercarz Eli E

    2011-07-01

    Full Text Available Abstract Background Non Obese Diabetic mice lacking B cells (NOD.Igμnull mice do not develop diabetes despite their susceptible background. Upon reconstitution of B cells using a chimera approach, animals start developing diabetes at 20 weeks of age. Methods We have used the spectratyping technique to follow the T cell receptor (TCR V beta repertoire of NOD.Igμnull mice following B cell reconstitution. This technique provides an unbiased approach to understand the kinetics of TCR expansion. We have also analyzed the TCR repertoire of reconstituted animals receiving cyclophosphamide treatment and following tissue transplants to identify common aggressive clonotypes. Results We found that B cell reconstitution of NOD.Igμnull mice induces a polyclonal TCR repertoire in the pancreas 10 weeks later, gradually diversifying to encompass most BV families. Interestingly, these clonotypic BV expansions are mainly confined to the pancreas and are absent from pancreatic lymph nodes or spleens. Cyclophosphamide-induced diabetes at 10 weeks post-B cell reconstitution reorganized the predominant TCR repertoires by removing potential regulatory clonotypes (BV1, BV8 and BV11 and increasing the frequency of others (BV4, BV5S2, BV9, BV16-20. These same clonotypes are more frequently present in neonatal pancreatic transplants under the kidney capsule of B-cell reconstituted diabetic NOD.Igμnull mice, suggesting their higher invasiveness. Phenotypic analysis of the pancreas-infiltrating lymphocytes during diabetes onset in B cell reconstituted animals show a predominance of CD19+ B cells with a B:T lymphocyte ratio of 4:1. In contrast, in other lymphoid organs (pancreatic lymph nodes and spleens analyzed by FACS, the B:T ratio was 1:1. Lymphocytes infiltrating the pancreas secrete large amounts of IL-6 and are of Th1 phenotype after CD3-CD28 stimulation in vitro. Conclusions Diabetes in NOD.Igμnull mice appears to be caused by a polyclonal repertoire of T cell

  2. Multiple sleep alterations in mice lacking cannabinoid type 1 receptors.

    Directory of Open Access Journals (Sweden)

    Alessandro Silvani

    Full Text Available Cannabinoid type 1 (CB1 receptors are highly expressed in the brain and play a role in behavior control. Endogenous cannabinoid signaling is modulated by high-fat diet (HFD. We investigated the consequences of congenital lack of CB1 receptors on sleep in mice fed standard diet (SD and HFD. CB1 cannabinoid receptor knock-out (KO and wild-type (WT mice were fed SD or HFD for 4 months (n = 9-10 per group. Mice were instrumented with electroencephalographic (EEG and electromyographic electrodes. Recordings were performed during baseline (48 hours, sleep deprivation (gentle handling, 6 hours, sleep recovery (18 hours, and after cage switch (insomnia model paradigm, 6 hours. We found multiple significant effects of genotype on sleep. In particular, KO spent more time awake and less time in non-rapid-eye-movement sleep (NREMS and rapid-eye-movement sleep (REMS than WT during the dark (active period but not during the light (rest period, enhancing the day-night variation of wake-sleep amounts. KO had slower EEG theta rhythm during REMS. REMS homeostasis after sleep deprivation was less effective in KO than in WT. Finally, KO habituated more rapidly to the arousing effect of the cage-switch test than WT. We did not find any significant effects of diet or of diet x genotype interaction on sleep. The occurrence of multiple sleep alterations in KO indicates important roles of CB1 cannabinoid receptors in limiting arousal during the active period of the day, in sleep regulation, and in sleep EEG in mice.

  3. The null hypothesis of GSEA, and a novel statistical model for competitive gene set analysis

    DEFF Research Database (Denmark)

    Debrabant, Birgit

    2017-01-01

    MOTIVATION: Competitive gene set analysis intends to assess whether a specific set of genes is more associated with a trait than the remaining genes. However, the statistical models assumed to date to underly these methods do not enable a clear cut formulation of the competitive null hypothesis....... This is a major handicap to the interpretation of results obtained from a gene set analysis. RESULTS: This work presents a hierarchical statistical model based on the notion of dependence measures, which overcomes this problem. The two levels of the model naturally reflect the modular structure of many gene set...... analysis methods. We apply the model to show that the popular GSEA method, which recently has been claimed to test the self-contained null hypothesis, actually tests the competitive null if the weight parameter is zero. However, for this result to hold strictly, the choice of the dependence measures...

  4. A few insights into the nature of classical and quantum gravity via null-strut calculus

    International Nuclear Information System (INIS)

    Kheyfets, Arkady

    1989-01-01

    Null-strut calculus is a 3 + 1 formulation of standard Regge calculus, wherein the dynamics of 3-geometry is propagated in time along light rays, or 'null struts'. However, just as Regge calculus is a discrete and geometric tool for the description of Einstein's theory of gravitation, so too NSC offers itself as a discrete and geometric tool for the description of Einstein's spacetime as the dynamics of discrete spacelike 3-geometries in time, or discrete geometrodynamics. It has for its objectives to provide a discrete model of a 3 + 1 split of spacetime into space plus time, while in so doing to preserve and illuminate the geometric content of Einstein's theory of gravity. The feature of 'light-cone-produced duality' is central to null-strut calculus. This paper will capitalise on this feature, and will attempt to provide some insights into the nature of classical and quantum gravity. (Author)

  5. Maxwell, Yang-Mills, Weyl and eikonal fields defined by any null shear-free congruence

    Science.gov (United States)

    Kassandrov, Vladimir V.; Rizcallah, Joseph A.

    We show that (specifically scaled) equations of shear-free null geodesic congruences on the Minkowski space-time possess intrinsic self-dual, restricted gauge and algebraic structures. The complex eikonal, Weyl 2-spinor, SL(2, ℂ) Yang-Mills and complex Maxwell fields, the latter produced by integer-valued electric charges (“elementary” for the Kerr-like congruences), can all be explicitly associated with any shear-free null geodesic congruence. Using twistor variables, we derive the general solution of the equations of the shear-free null geodesic congruence (as a modification of the Kerr theorem) and analyze the corresponding “particle-like” field distributions, with bounded singularities of the associated physical fields. These can be obtained in a straightforward algebraic way and exhibit nontrivial collective dynamics simulating physical interactions.

  6. The (2, 0) superalgebra, null M-branes and Hitchin's system

    Science.gov (United States)

    Kucharski, P.; Lambert, N.; Owen, M.

    2017-10-01

    We present an interacting system of equations with sixteen supersymmetries and an SO(2) × SO(6) R-symmetry where the fields depend on two space and one null dimensions that is derived from a representation of the six-dimensional (2, 0) superalgebra. The system can be viewed as two M5-branes compactified on {S}-^1× T^2 or equivalently as M2-branes on R+× R^2 , where ± refer to null directions. We show that for a particular choice of fields the dynamics can be reduced to motion on the moduli space of solutions to the Hitchin system. We argue that this provides a description of intersecting null M2-branes and is also related by U-duality to a DLCQ description of four-dimensional maximally supersymmetric Yang-Mills.

  7. ENU mutagenesis reveals a novel phenotype of reduced limb strength in mice lacking fibrillin 2.

    Directory of Open Access Journals (Sweden)

    Gaynor Miller

    2010-02-01

    Full Text Available Fibrillins 1 (FBN1 and 2 (FBN2 are components of microfibrils, microfilaments that are present in many connective tissues, either alone or in association with elastin. Marfan's syndrome and congenital contractural arachnodactyly (CCA result from dominant mutations in the genes FBN1 and FBN2 respectively. Patients with both conditions often present with specific muscle atrophy or weakness, yet this has not been reported in the mouse models. In the case of Fbn1, this is due to perinatal lethality of the homozygous null mice making measurements of strength difficult. In the case of Fbn2, four different mutant alleles have been described in the mouse and in all cases syndactyly was reported as the defining phenotypic feature of homozygotes.As part of a large-scale N-ethyl-N-nitrosourea (ENU mutagenesis screen, we identified a mouse mutant, Mariusz, which exhibited muscle weakness along with hindlimb syndactyly. We identified an amber nonsense mutation in Fbn2 in this mouse mutant. Examination of a previously characterised Fbn2-null mutant, Fbn2(fp, identified a similar muscle weakness phenotype. The two Fbn2 mutant alleles complement each other confirming that the weakness is the result of a lack of Fbn2 activity. Skeletal muscle from mutants proved to be abnormal with higher than average numbers of fibres with centrally placed nuclei, an indicator that there are some regenerating muscle fibres. Physiological tests indicated that the mutant muscle produces significantly less maximal force, possibly as a result of the muscles being relatively smaller in Mariusz mice.These findings indicate that Fbn2 is involved in integrity of structures required for strength in limb movement. As human patients with mutations in the fibrillin genes FBN1 and FBN2 often present with muscle weakness and atrophy as a symptom, Fbn2-null mice will be a useful model for examining this aspect of the disease process further.

  8. Suppression of Langerhans cell activation is conserved amongst human papillomavirus α and β genotypes, but not a µ genotype.

    Science.gov (United States)

    Da Silva, Diane M; Movius, Carly A; Raff, Adam B; Brand, Heike E; Skeate, Joseph G; Wong, Michael K; Kast, W Martin

    2014-03-01

    Human papillomavirus (HPV) has evolved mechanisms that allow it to evade the human immune system. Studies have shown HPV-mediated suppression of activation of Langerhans cells (LC) is a key mechanism through which HPV16 evades initial immune surveillance. However, it has not been established whether high- and low-risk mucosal and cutaneous HPV genotypes share a common mechanism of immune suppression. Here, we demonstrate that LC exposed to capsids of HPV types 18, 31, 45, 11, (alpha-papillomaviruses) and HPV5 (beta-papillomavirus) similarly suppress LC activation, including lack of costimulatory molecule expression, lack of cytokine and chemokine secretion, lack of migration, and deregulated cellular signaling. In contrast, HPV1 (mu-papillomavirus) induced costimulatory molecule and cytokine upregulation, but LC migration and cellular signaling was suppressed. These results suggest that alpha and beta HPV genotypes, and partially a mu genotype, share a conserved mechanism of immune escape that enables these viruses to remain undetected in the absence of other inflammatory events. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. From GLC to double-null coordinates and illustration with static black holes

    Energy Technology Data Exchange (ETDEWEB)

    Nugier, Fabien, E-mail: fnugier@ntu.edu.tw [Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei, 10617 Taiwan (China)

    2016-09-01

    We present a system of coordinates deriving directly from the so-called Geodesic Light-Cone (GLC) coordinates and made of two null scalars intersecting on a 2-dimensional sphere parameterized by two constant angles along geodesics. These coordinates are shown to be equivalent to the well-known double-null coordinates. As GLC, they present interesting properties for cosmology and astrophysics. We discuss this latter topic for static black holes, showing simple descriptions for the metric or particles and photons trajectories. We also briefly comment on the time of flight of ultra-relativistic particles.

  10. The Segmented Aperture Interferometric Nulling Testbed (SAINT) I: overview and air-side system description

    Science.gov (United States)

    Hicks, Brian A.; Lyon, Richard G.; Petrone, Peter; Ballard, Marlin; Bolcar, Matthew R.; Bolognese, Jeff; Clampin, Mark; Dogoda, Peter; Dworzanski, Daniel; Helmbrecht, Michael A.; Koca, Corina; Shiri, Ron

    2016-07-01

    This work presents an overview of the Segmented Aperture Interferometric Nulling Testbed (SAINT), a project that will pair an actively-controlled macro-scale segmented mirror with the Visible Nulling Coronagraph (VNC). SAINT will incorporate the VNC's demonstrated wavefront sensing and control system to refine and quantify end-to-end high-contrast starlight suppression performance. This pathfinder testbed will be used as a tool to study and refine approaches to mitigating instabilities and complex diffraction expected from future large segmented aperture telescopes.

  11. Noncolocated Time-Reversal MUSIC: High-SNR Distribution of Null Spectrum

    Science.gov (United States)

    Ciuonzo, Domenico; Rossi, Pierluigi Salvo

    2017-04-01

    We derive the asymptotic distribution of the null spectrum of the well-known Multiple Signal Classification (MUSIC) in its computational Time-Reversal (TR) form. The result pertains to a single-frequency non-colocated multistatic scenario and several TR-MUSIC variants are here investigated. The analysis builds upon the 1st-order perturbation of the singular value decomposition and allows a simple characterization of null-spectrum moments (up to the 2nd order). This enables a comparison in terms of spectrums stability. Finally, a numerical analysis is provided to confirm the theoretical findings.

  12. In vivo time-gated diffuse correlation spectroscopy at quasi-null source-detector separation.

    Science.gov (United States)

    Pagliazzi, M; Sekar, S Konugolu Venkata; Di Sieno, L; Colombo, L; Durduran, T; Contini, D; Torricelli, A; Pifferi, A; Mora, A Dalla

    2018-06-01

    We demonstrate time domain diffuse correlation spectroscopy at quasi-null source-detector separation by using a fast time-gated single-photon avalanche diode without the need of time-tagging electronics. This approach allows for increased photon collection, simplified real-time instrumentation, and reduced probe dimensions. Depth discriminating, quasi-null distance measurement of blood flow in a human subject is presented. We envision the miniaturization and integration of matrices of optical sensors of increased spatial resolution and the enhancement of the contrast of local blood flow changes.

  13. A class of algebraically general solutions of the Einstein-Maxwell equations for non-null electromagnetic fields

    International Nuclear Information System (INIS)

    Tupper, B.O.J.

    1976-01-01

    In a previous article (Gen. Rel. Grav.; 6 : 345 (1975)) the Einstein-Maxwell field equations for non-null electromagnetic fields were studied under the conditions that the null tetrad is parallel-propagated along both principal null congruences. A solution with twist and shear, but no expansion, was found and was conjectured to be the only expansion-free solution. Here it is shown that this conjecture is false; the general expansion-free solution is found to be a family of space-times depending on a single constant parameter which is the ratio of the (constant) twists of the two principal null congruences. (author)

  14. FTO genotype and weight loss

    DEFF Research Database (Denmark)

    Livingstone, Katherine M; Celis-Morales, Carlos; Papandonatos, George D

    2016-01-01

    : Ovid Medline, Scopus, Embase, and Cochrane from inception to November 2015. ELIGIBILITY CRITERIA FOR STUDY SELECTION: Randomised controlled trials in overweight or obese adults reporting reduction in body mass index, body weight, or waist circumference by FTO genotype (rs9939609 or a proxy) after...

  15. FTO genotype and weight loss

    DEFF Research Database (Denmark)

    Livingstone, Katherine M; Celis-Morales, Carlos; Papandonatos, George D

    2016-01-01

    OBJECTIVE: To assess the effect of the FTO genotype on weight loss after dietary, physical activity, or drug based interventions in randomised controlled trials. DESIGN: Systematic review and random effects meta-analysis of individual participant data from randomised controlled trials. DATA SOURC...

  16. Lack of Melanopsin Is Associated with Extreme Weight Loss in Mice upon Dietary Challenge.

    Directory of Open Access Journals (Sweden)

    Didem Göz Aytürk

    Full Text Available Metabolic disorders have been established as major risk factors for ocular complications and poor vision. However, little is known about the inverse possibility that ocular disease may cause metabolic dysfunction. To test this hypothesis, we assessed the metabolic consequences of a robust dietary challenge in several mouse models suffering from retinal mutations. To this end, mice null for melanopsin (Opn4-/-, the photopigment of intrinsically photosensitive retinal ganglion cells (ipRGCs, were subjected to five weeks of a ketogenic diet. These mice lost significantly more weight than wild-type controls or mice lacking rod and cone photoreceptors (Pde6brd1/rd1. Although ipRGCs are critical for proper circadian entrainment, and circadian misalignment has been implicated in metabolic pathology, we observed no differences in entrainment between Opn4-/- and control mice. Additionally, we observed no differences in any tested metabolic parameter between these mouse strains. Further studies are required to establish the mechanism giving rise to this dramatic phenotype observed in melanopsin-null mice. We conclude that the causality between ocular disease and metabolic disorders merits further investigation due to the popularity of diets that rely on the induction of a ketogenic state. Our study is a first step toward understanding retinal pathology as a potential cause of metabolic dysfunction.

  17. EMK protein kinase-null mice: dwarfism and hypofertility associated with alterations in the somatotrope and prolactin pathways.

    Science.gov (United States)

    Bessone, S; Vidal, F; Le Bouc, Y; Epelbaum, J; Bluet-Pajot, M T; Darmon, M

    1999-10-01

    Gene trapping was used in embryonic stem (ES) cells in an attempt to inactivate genes involved in development. The Emk (ELKL motif kinase) gene has been disrupted and a mutant mouse line derived. Previous work had shown that EMK kinases, called MARK in the rat, exert a major control on microtubule stability by phosphorylating microtubule-associated proteins and that genes homologous to Emk in yeast or Caenorhabditis elegans are essential for cell and embryonic polarity. Although we found the Emk gene to be active in the preimplantation mouse embryo and then to show a widespread expression, Emk-null mice had no embryonic defect and were viable. They show an overall proportionate dwarfism and a peculiar hypofertility: homozygotes are not fertile when intercrossed, but are fertile in other types of crosses. Insulin-like growth factor I (IGF I) and IGF-binding protein 3 (IGFBP3) were reduced in the plasma of homozygotes of both sexes. A direct implication of the EMK kinase in IGF I plasmatic production is unlikely because the Emk gene does not seem to be expressed in hepatocytes. Nevertheless, GH assayed at arbitrary times in plasma did not show differences between genotypes and GH concentrations in pituitary extracts were not found to be altered in homozygotes. Our results, though, do not exclude the possibility that in the mutants the overall quantity of GH secreted daily is reduced. Our observation of a smaller size of the pituitaries of the mutants is in favor of this hypothesis. The prolactin concentration in the pituitaries was much lowered in homozygous females, but it was normal in males. The possible involvement of EMK protein kinase in hormone secretion in the pituitary and/or the hypothalamus, via the microtubule network, is discussed. Copyright 1999 Academic Press.

  18. Hepatitis C Virus: Virology and Genotypes

    KAUST Repository

    Abdelaziz, Ahmed

    2017-01-01

    Hepatitis C virus (HCV) is a major causative agent of chronic liver disease worldwide. HCV is characterized by genetic heterogeneity, with at least six genotypes identified. The geographic distribution of genotypes has shown variations in different

  19. Propagation of errors from a null balance terahertz reflectometer to a sample's relative water content

    International Nuclear Information System (INIS)

    Hadjiloucas, S; Walker, G C; Bowen, J W; Zafiropoulos, A

    2009-01-01

    The THz water content index of a sample is defined and advantages in using such metric in estimating a sample's relative water content are discussed. The errors from reflectance measurements performed at two different THz frequencies using a quasi-optical null-balance reflectometer are propagated to the errors in estimating the sample water content index.

  20. Partial null astigmatism-compensated interferometry for a concave freeform Zernike mirror

    Science.gov (United States)

    Dou, Yimeng; Yuan, Qun; Gao, Zhishan; Yin, Huimin; Chen, Lu; Yao, Yanxia; Cheng, Jinlong

    2018-06-01

    Partial null interferometry without using any null optics is proposed to measure a concave freeform Zernike mirror. Oblique incidence on the freeform mirror is used to compensate for astigmatism as the main component in its figure, and to constrain the divergence of the test beam as well. The phase demodulated from the partial nulled interferograms is divided into low-frequency phase and high-frequency phase by Zernike polynomial fitting. The low-frequency surface figure error of the freeform mirror represented by the coefficients of Zernike polynomials is reconstructed from the low-frequency phase, applying the reverse optimization reconstruction technology in the accurate model of the interferometric system. The high-frequency surface figure error of the freeform mirror is retrieved from the high-frequency phase adopting back propagating technology, according to the updated model in which the low-frequency surface figure error has been superimposed on the sag of the freeform mirror. Simulations verified that this method is capable of testing a wide variety of astigmatism-dominated freeform mirrors due to the high dynamic range. The experimental result using our proposed method for a concave freeform Zernike mirror is consistent with the null test result employing the computer-generated hologram.

  1. High Contrast Vacuum Nuller Testbed (VNT) Contrast, Performance and Null Control

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.

    2012-01-01

    Herein we report on our Visible Nulling Coronagraph high-contrast result of 109 contrast averaged over a focal planeregion extending from 14 D with the Vacuum Nuller Testbed (VNT) in a vibration isolated vacuum chamber. TheVNC is a hybrid interferometriccoronagraphic approach for exoplanet science. It operates with high Lyot stopefficiency for filled, segmented and sparse or diluted-aperture telescopes, thereby spanning the range of potential futureNASA flight telescopes. NASAGoddard Space Flight Center (GSFC) has a well-established effort to develop the VNCand its technologies, and has developed an incremental sequence of VNC testbeds to advance this approach and itsenabling technologies. These testbeds have enabled advancement of high-contrast, visible light, nulling interferometry tounprecedented levels. The VNC is based on a modified Mach-Zehnder nulling interferometer, with a W configurationto accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters.We give an overview of the VNT and discuss the high-contrast laboratory results, the optical configuration, criticaltechnologies and null sensing and control.

  2. Modelling the electromechanical interactions in a null-flux EDS Maglev system

    NARCIS (Netherlands)

    Boeij, de J.; Steinbuch, M.; Gutierrez, H.M.; Fair, H.D.

    2004-01-01

    The fundamental electromechanical interactionsin a passive null-ux EDS maglev system aremediated by the voltages induced in the levita-tion coils by the sled magnets, and by the forcesexerted on the sled as a result of the inducedcurrents. This paper presents a reliable andcompact method to

  3. Parallel-propagated frame along null geodesics in higher-dimensional black hole spacetimes

    International Nuclear Information System (INIS)

    Kubiznak, David; Frolov, Valeri P.; Connell, Patrick; Krtous, Pavel

    2009-01-01

    In [arXiv:0803.3259] the equations describing the parallel transport of orthonormal frames along timelike (spacelike) geodesics in a spacetime admitting a nondegenerate principal conformal Killing-Yano 2-form h were solved. The construction employed is based on studying the Darboux subspaces of the 2-form F obtained as a projection of h along the geodesic trajectory. In this paper we demonstrate that, although slightly modified, a similar construction is possible also in the case of null geodesics. In particular, we explicitly construct the parallel-transported frames along null geodesics in D=4, 5, 6 Kerr-NUT-(A)dS spacetimes. We further discuss the parallel transport along principal null directions in these spacetimes. Such directions coincide with the eigenvectors of the principal conformal Killing-Yano tensor. Finally, we show how to obtain a parallel-transported frame along null geodesics in the background of the 4D Plebanski-Demianski metric which admits only a conformal generalization of the Killing-Yano tensor.

  4. Diversity-Multiplexing-Nulling Trade-Off Analysis of Multiuser MIMO System for Intercell Interference Coordination

    Directory of Open Access Journals (Sweden)

    Jinwoo Kim

    2017-01-01

    Full Text Available A fundamental performance trade-off of multicell multiuser multiple-input multiple-output (MU-MIMO systems is explored for achieving intercell and intracell interference-free conditions. In particular, we analyze the three-dimensional diversity-multiplexing-nulling trade-off (DMNT among the diversity order (i.e., the slope of the error performance curve, multiplexing order (i.e., the number of users that are simultaneously served by MU-MIMO, and nulling order (i.e., the number of users with zero interference in a victim cell. This trade-off quantifies the performance of MU-MIMO in terms of its diversity and multiplexing order, while nulling the intercell interference toward the victim cell in the neighbor. First, we design a precoding matrix to mitigate both intercell and intracell interference for a linear precoding-based MU-MIMO system. Then, the trade-off relationship is obtained by analyzing the distribution of the signal-to-noise ratio (SNR at the user terminals. Furthermore, we demonstrate how DMNT can be applied to estimate the long-term throughput for each mobile station, which allows for determining the optimal number of multiplexing order and throughput loss due to the interference nulling.

  5. Exact null distributions of quadratic distribution-free statistics for two-way classification

    NARCIS (Netherlands)

    Wiel, van de M.A.

    2004-01-01

    Abstract We present new techniques for computing exact distributions of `Friedman-type¿ statistics. Representing the null distribution by a generating function allows for the use of general, not necessarily integer-valued rank scores. Moreover, we use symmetry properties of the multivariate

  6. Pattern Nulling of Linear Antenna Arrays Using Backtracking Search Optimization Algorithm

    Directory of Open Access Journals (Sweden)

    Kerim Guney

    2015-01-01

    Full Text Available An evolutionary method based on backtracking search optimization algorithm (BSA is proposed for linear antenna array pattern synthesis with prescribed nulls at interference directions. Pattern nulling is obtained by controlling only the amplitude, position, and phase of the antenna array elements. BSA is an innovative metaheuristic technique based on an iterative process. Various numerical examples of linear array patterns with the prescribed single, multiple, and wide nulls are given to illustrate the performance and flexibility of BSA. The results obtained by BSA are compared with the results of the following seventeen algorithms: particle swarm optimization (PSO, genetic algorithm (GA, modified touring ant colony algorithm (MTACO, quadratic programming method (QPM, bacterial foraging algorithm (BFA, bees algorithm (BA, clonal selection algorithm (CLONALG, plant growth simulation algorithm (PGSA, tabu search algorithm (TSA, memetic algorithm (MA, nondominated sorting GA-2 (NSGA-2, multiobjective differential evolution (MODE, decomposition with differential evolution (MOEA/D-DE, comprehensive learning PSO (CLPSO, harmony search algorithm (HSA, seeker optimization algorithm (SOA, and mean variance mapping optimization (MVMO. The simulation results show that the linear antenna array synthesis using BSA provides low side-lobe levels and deep null levels.

  7. On the geometry of null cones to infinity under curvature flux bounds

    International Nuclear Information System (INIS)

    Alexakis, Spyros; Shao, Arick

    2014-01-01

    The main objective of this paper is to control the geometry of a future outgoing truncated null cone extending smoothly toward infinity in an Einstein-vacuum spacetime. In particular, we wish to do this under minimal regularity assumptions, namely, at the (weighted) L 2 -curvature level. We show that if the curvature flux and the data on an initial sphere of the cone are sufficiently close to the corresponding values in a standard Minkowski or Schwarzschild null cone, then we can obtain quantitative bounds on the geometry of the entire infinite cone. The same bounds also imply the existence of limits at infinity, along the null cone, of naturally scaled geometric quantities. In Alexakis and Shao (2013 Bounds on the Bondi energy by a flux of curvature arXiv:1308.4170), we will apply these results in order to control various physical quantities—e.g., the Bondi energy and (linear and angular) momenta—associated with such infinite null cones in vacuum spacetimes. (paper)

  8. Altered extracellular matrix remodeling and angiogenesis in sponge granulomas of thrombospondin 2-null mice.

    Science.gov (United States)

    Kyriakides, T R; Zhu, Y H; Yang, Z; Huynh, G; Bornstein, P

    2001-10-01

    The matricellular angiogenesis inhibitor, thrombospondin (TSP) 2, has been shown to be an important modulator of wound healing and the foreign body response. Specifically, TSP2-null mice display improved healing with minimal scarring and form well-vascularized foreign body capsules. In this study we performed subcutaneous implantation of sponges and investigated the resulting angiogenic and fibrogenic responses. Histological and immunohistochemical analysis of sponges, excised at 7, 14, and 21 days after implantation, revealed significant differences between TSP2-null and wild-type mice. Most notably, TSP2-null mice exhibited increased angiogenesis and fibrotic encapsulation of the sponge. However, invasion of dense tissue was compromised, even though its overall density was increased. Furthermore, histomorphometry and biochemical assays demonstrated a significant increase in the extracellular distribution of matrix metalloproteinase (MMP) 2, but no change in the levels of active transforming growth factor-beta(1). The alterations in neovascularization, dense tissue invasion, and MMP2 in TSP2-null mice coincided with the deposition of TSP2 in the extracellular matrix of wild-type animals. These observations support the proposed role of TSP2 as a modulator of angiogenesis and matrix remodeling during tissue repair. In addition, they provide in vivo evidence for a newly proposed function of TSP2 as a modulator of extracellular MMP2 levels.

  9. A Coding of Real Null Four-Momenta into World-Sheet Coordinates

    Directory of Open Access Journals (Sweden)

    David B. Fairlie

    2009-01-01

    Full Text Available The results of minimizing the action for string-like systems on a simply connected world sheet are shown to encode the Cartesian components of real null momentum four-vectors into coordinates on the world sheet. This identification arises consistently from different approaches to the problem.

  10. A Coding of Real Null Four-Momenta into World-Sheet Co-ordinates

    OpenAIRE

    Fairlie, David B.

    2008-01-01

    The results of minimizing the action for string-like systems on a simply-connected world sheet are shown to encode the Cartesian components of real null momentum four-vectors into co-ordinates on the world sheet. This identification arises consistently from different approaches to the problem.

  11. A Panel Test of Purchasing Power Parity Under the Null of Stationarity

    OpenAIRE

    Hunter, J; Simpson, M

    2001-01-01

    Purchasing Power Parity (PPP) is tested using a sample of real exchange rate data for twelve European countries. Acknowledging that Augmented Dickey Fuller tests have low power, we apply a Panel test that considers the null of stationarity and corrects for serial dependence using a non-parametric kernel based method.

  12. Stitching interferometry of high numerical aperture cylindrical optics without using a fringe-nulling routine.

    Science.gov (United States)

    Peng, Junzheng; Wang, Qingquan; Peng, Xiang; Yu, Yingjie

    2015-11-01

    Stitching interferometry is a common method for measuring the figure error of high numerical aperture optics. However, subaperture measurement usually requires a fringe-nulling routine, thus making the stitching procedure complex and time-consuming. The challenge when measuring a surface without a fringe-nulling routine is that the rays no longer perpendicularly hit the surface. This violation of the null-test condition can lead to high fringe density and introduce high-order misalignment aberrations into the measurement result. This paper demonstrates that the high-order misalignment aberrations can be characterized by low-order misalignment aberrations; then, an efficient method is proposed to separate the high-order misalignment aberrations from subaperture data. With the proposed method, the fringe-nulling routine is not required. Instead, the subaperture data is measured under a nonzero fringe pattern. Then, all possible misalignment aberrations are removed with the proposed method. Finally, the full aperture map is acquired by connecting all subaperture data together. Experimental results showing the feasibility of the proposed procedure are presented.

  13. High contrast vacuum nuller testbed (VNT) contrast, performance, and null control

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Madison, Timothy; Bolcar, Matthew R.

    2012-09-01

    Herein we report on our Visible Nulling Coronagraph high-contrast result of 109 contrast averaged over a focal plane region extending from 1 - 4 λ/D with the Vacuum Nuller Testbed (VNT) in a vibration isolated vacuum chamber. The VNC is a hybrid interferometric/coronagraphic approach for exoplanet science. It operates with high Lyot stop efficiency for filled, segmented and sparse or diluted-aperture telescopes, thereby spanning the range of potential future NASA flight telescopes. NASA/Goddard Space Flight Center (GSFC) has a well-established effort to develop the VNC and its technologies, and has developed an incremental sequence of VNC testbeds to advance this approach and its enabling technologies. These testbeds have enabled advancement of high-contrast, visible light, nulling interferometry to unprecedented levels. The VNC is based on a modified Mach-Zehnder nulling interferometer, with a “W” configuration to accommodate a hex-packed MEMS based deformable mirror, a coherent fiber bundle and achromatic phase shifters. We give an overview of the VNT and discuss the high-contrast laboratory results, the optical configuration, critical technologies and null sensing and control.

  14. Development of IR single mode optical fibers for DARWIN-nulling interferometry

    NARCIS (Netherlands)

    Chakkalakkal Abdulla, S.M.; Cheng, L.K.; Bosch, B. van den; Dijkhuizen, N.; Nieuwland, R.A.; Gielesen, W.L.M.; Lucas, J.; Boussard-Plédel, C.; Conseil, C.; Bureau, B.; Carmo, J.P. do

    2014-01-01

    The DARWIN mission aims to detect weak infra-red emission lines from distant orbiting earth-like planets using nulling interferometry. This requires filtering of wavefront errors using single mode waveguides operating at a wavelength range of 6.5-20 μm. This article describes the optical design of

  15. The Need for Nuance in the Null Hypothesis Significance Testing Debate

    Science.gov (United States)

    Häggström, Olle

    2017-01-01

    Null hypothesis significance testing (NHST) provides an important statistical toolbox, but there are a number of ways in which it is often abused and misinterpreted, with bad consequences for the reliability and progress of science. Parts of contemporary NHST debate, especially in the psychological sciences, is reviewed, and a suggestion is made…

  16. Integrable structures and the quantization of free null initial data for gravity

    Science.gov (United States)

    Fuchs, Andreas; Reisenberger, Michael P.

    2017-09-01

    Variables for constraint free null canonical vacuum general relativity are presented which have simple Poisson brackets that facilitate quantization. Free initial data for vacuum general relativity on a pair of intersecting null hypersurfaces has been known since the 1960s. These consist of the ‘main’ data which are set on the bulk of the two null hypersurfaces, and additional ‘surface’ data set only on their intersection 2-surface. More recently the complete set of Poisson brackets of such data has been obtained. However the complexity of these brackets is an obstacle to their quantization. Part of this difficulty may be overcome using methods from the treatment of cylindrically symmetric gravity. Specializing from general to cylindrically symmetric solutions changes the Poisson algebra of the null initial data surprisingly little, but cylindrically symmetric vacuum general relativity is an integrable system, making powerful tools available. Here a transformation is constructed at the cylindrically symmetric level which maps the main initial data to new data forming a Poisson algebra for which an exact deformation quantization is known. (Although an auxiliary condition on the data has been quantized only in the asymptotically flat case, and a suitable representation of the algebra of quantum data by operators on a Hilbert space has not yet been found.) The definition of the new main data generalizes naturally to arbitrary, symmetryless gravitational fields, with the Poisson brackets retaining their simplicity. The corresponding generalization of the quantization is however ambiguous and requires further analysis.

  17. Reduced infarct size in neuroglobin-null mice after experimental stroke in vivo

    DEFF Research Database (Denmark)

    Raida, Zindy; Hundahl, Christian Ansgar; Kelsen, Jesper

    2012-01-01

    Neuroglobin is considered to be a novel important pharmacological target in combating stroke and neurodegenerative disorders, although the mechanism by which this protection is accomplished remains an enigma. We hypothesized that if neuroglobin is directly involved in neuroprotection, then perman......, then permanent cerebral ischemia would lead to larger infarct volumes in neuroglobin-null mice than in wild-type mice....

  18. Interpretation of Chinese Overt and Null Embedded Arguments by English-Speaking Learners

    Science.gov (United States)

    Zhao, Lucy Xia

    2012-01-01

    It has been proposed that external interfaces are vulnerable to residue optionality, whereas pure syntax and internal interfaces are acquirable in second language (L2) acquisition (Sorace, 2005, 2011; Sorace and Filiaci, 2006). The proposal was tested in this article through the interpretation of overt and null embedded arguments in L2 Chinese…

  19. Simple Fourier optics formalism for high-angular-resolution systems and nulling interferometry.

    Science.gov (United States)

    Hénault, François

    2010-03-01

    Reviewed are various designs of advanced, multiaperture optical systems dedicated to high-angular-resolution imaging or to the detection of exoplanets by nulling interferometry. A simple Fourier optics formalism applicable to both imaging arrays and nulling interferometers is presented, allowing their basic theoretical relationships to be derived as convolution or cross-correlation products suitable for fast and accurate computation. Several unusual designs, such as a "superresolving telescope" utilizing a mosaicking observation procedure or a free-flying, axially recombined interferometer are examined, and their performance in terms of imaging and nulling capacity are assessed. In all considered cases, it is found that the limiting parameter is the diameter of the individual telescopes. A final section devoted to nulling interferometry shows an apparent superiority of axial versus multiaxial recombining schemes. The entire study is valid only in the framework of first-order geometrical optics and scalar diffraction theory. Furthermore, it is assumed that all entrance subapertures are optically conjugated with their associated exit pupils.

  20. Hamilton-Jacobi formalism for Podolsky's electromagnetic theory on the null-plane

    Science.gov (United States)

    Bertin, M. C.; Pimentel, B. M.; Valcárcel, C. E.; Zambrano, G. E. R.

    2017-08-01

    We develop the Hamilton-Jacobi formalism for Podolsky's electromagnetic theory on the null-plane. The main goal is to build the complete set of Hamiltonian generators of the system as well as to study the canonical and gauge transformations of the theory.

  1. What Constitutes Science and Scientific Evidence: Roles of Null Hypothesis Testing

    Science.gov (United States)

    Chang, Mark

    2017-01-01

    We briefly discuss the philosophical basis of science, causality, and scientific evidence, by introducing the hidden but most fundamental principle of science: the similarity principle. The principle's use in scientific discovery is illustrated with Simpson's paradox and other examples. In discussing the value of null hypothesis statistical…

  2. THE NATURE OF FLARE RIBBONS IN CORONAL NULL-POINT TOPOLOGY

    International Nuclear Information System (INIS)

    Masson, S.; Aulanier, G.; Pariat, E.; Schrijver, C. J.

    2009-01-01

    Flare ribbons are commonly attributed to the low-altitude impact, along the footprints of separatrices or quasi-separatrix layers (QSLs), of particle beams accelerated through magnetic reconnection. If reconnection occurs at a three-dimensional coronal magnetic null point, the footprint of the dome-shaped fan surface would map a closed circular ribbon. This paper addresses the following issues: does the entire circular ribbon brighten simultaneously, as expected because all fan field lines pass through the null point? And since the spine separatrices are singular field lines, do spine-related ribbons look like compact kernels? What can we learn from these observations about current sheet formation and magnetic reconnection in a null-point topology? The present study addresses these questions by analyzing Transition Region and Coronal Explorer and Solar and Heliospheric Observatory/Michelson Doppler Imager observations of a confined flare presenting a circular ribbon. Using a potential field extrapolation, we linked the circular shape of the ribbon with the photospheric mapping of the fan field lines originating from a coronal null point. Observations show that the flare ribbon outlining the fan lines brightens sequentially along the counterclockwise direction and that the spine-related ribbons are elongated. Using the potential field extrapolation as initial condition, we conduct a low-β resistive magnetohydrodynamics simulation of this observed event. We drive the coronal evolution by line-tied diverging boundary motions, so as to emulate the observed photospheric flow pattern associated with some magnetic flux emergence. The numerical analysis allows us to explain several observed features of the confined flare. The vorticity induced in the fan by the prescribed motions causes the spines to tear apart along the fan. This leads to formation of a thin current sheet and induces null-point reconnection. We also find that the null point and its associated topological

  3. A Phenomenological Study on Lack of Motivation

    Science.gov (United States)

    Educational Research and Reviews, 2013

    2013-01-01

    The aim of this research is to point out the underlying reasons about the lack of motivation at academic activities concerning Attribution Theory. Attribution Theory trys to understand how the people answer "why" question and how they do casual explanations. This research is a qualitative based research. It used the phenomenological…

  4. Impaired cutaneous wound healing in mice lacking tetranectin

    DEFF Research Database (Denmark)

    Iba, Kousuke; Hatakeyama, Naoko; Kojima, Takashi

    2009-01-01

    disruption of the tetranectin gene to elucidate the biological function of tetranectin. In this study, we showed that wound healing was markedly delayed in tetranectin-null mice compared with wild-type mice. A single full-thickness incision was made in the dorsal skin. By 14 days after the incision......, the wounds fully healed in all wild-type mice based on the macroscopic closure; in contrast, the progress of wound healing in the tetranectin null mice appeared to be impaired. In histological analysis, wounds of wild-type mice showed complete reepithelialization and healed by 14 days after the incision....... However, those of tetranectin-null mice never showed complete reepithelialization at 14 days. At 21 days after the injury, the wound healed and was covered with an epidermis. These results supported the fact that tetranectin may play a role in the wound healing process....

  5. Reversing hypomyelination in BACE1-null mice with Akt-DD overexpression.

    Science.gov (United States)

    Hu, Xiangyou; Schlanger, Rita; He, Wanxia; Macklin, Wendy B; Yan, Riqiang

    2013-05-01

    β-Site amyloid precursor protein convertase enzyme 1 (BACE1), a type I transmembrane aspartyl protease required to cleave amyloid precursor protein for releasing a toxic amyloid peptide, also cleaves type I and type III neuregulin-1 (Nrg-1). BACE1 deficiency in mice causes hypomyelination during development and impairs remyelination if injured. In BACE1-null mice, the abolished cleavage of neuregulin-1 by BACE1 is speculated to cause reduced myelin sheath thickness in both the central nervous system and peripheral nervous system because reduced cleavage of Nrg-1 correlates with reduced Akt phosphorylation, a downstream signaling molecule of the Nrg-1/ErbB pathway. Here we tested specifically whether increasing Akt activity alone in oligodendrocytes would be sufficient to reverse the hypomyelination phenotype in BACE1-null mice. BACE1-null mice were bred with transgenic mice expressing constitutively active Akt (Akt-DD; mutations with D(308)T and D(473)S) in oligodendrocytes. Relative to littermate BACE1-null controls, BACE1(-/-)/Akt-DD mice exhibited enhanced expression of myelin basic protein and promoter of proteolipid protein. The elevated expression of myelin proteins correlated with a thicker myelin sheath in optic nerves; comparison of quantified g ratios with statistic significance was used to confirm this reversion. However, it appeared that myelin sheath thickness in the sciatic nerves was not increased in BACE1(-/-)/Akt-DD mice, as the g ratio was not significantly different from the control. Hence, increased Akt activity in BACE1-null myelinating cells only compensates for the loss of BACE1 activity in the central nervous system, which is consistent with the observation that overexpression of Akt-DD in Schwann cells did not induce hypermyelination. Our results suggest that signaling activity other than Akt may also contribute to proper myelination in peripheral nerves.

  6. Orexin Receptor Antagonism Improves Sleep and Reduces Seizures in Kcna1-null Mice.

    Science.gov (United States)

    Roundtree, Harrison M; Simeone, Timothy A; Johnson, Chaz; Matthews, Stephanie A; Samson, Kaeli K; Simeone, Kristina A

    2016-02-01

    Comorbid sleep disorders occur in approximately one-third of people with epilepsy. Seizures and sleep disorders have an interdependent relationship where the occurrence of one can exacerbate the other. Orexin, a wake-promoting neuropeptide, is associated with sleep disorder symptoms. Here, we tested the hypothesis that orexin dysregulation plays a role in the comorbid sleep disorder symptoms in the Kcna1-null mouse model of temporal lobe epilepsy. Rest-activity was assessed using infrared beam actigraphy. Sleep architecture and seizures were assessed using continuous video-electroencephalography-electromyography recordings in Kcna1-null mice treated with vehicle or the dual orexin receptor antagonist, almorexant (100 mg/kg, intraperitoneally). Orexin levels in the lateral hypothalamus/perifornical region (LH/P) and hypothalamic pathology were assessed with immunohistochemistry and oxygen polarography. Kcna1-null mice have increased latency to rapid eye movement (REM) sleep onset, sleep fragmentation, and number of wake epochs. The numbers of REM and non-REM (NREM) sleep epochs are significantly reduced in Kcna1-null mice. Severe seizures propagate to the wake-promoting LH/P where injury is apparent (indicated by astrogliosis, blood-brain barrier permeability, and impaired mitochondrial function). The number of orexin-positive neurons is increased in the LH/P compared to wild-type LH/P. Treatment with a dual orexin receptor antagonist significantly increases the number and duration of NREM sleep epochs and reduces the latency to REM sleep onset. Further, almorexant treatment reduces the incidence of severe seizures and overall seizure burden. Interestingly, we report a significant positive correlation between latency to REM onset and seizure burden in Kcna1-null mice. Dual orexin receptor antagonists may be an effective sleeping aid in epilepsy, and warrants further study on their somnogenic and ant-seizure effects in other epilepsy models. © 2016 Associated

  7. Genotype x environment interaction and optimum resource ...

    African Journals Online (AJOL)

    ... x E) interaction and to determine the optimum resource allocation for cassava yield trials. The effects of environment, genotype and G x E interaction were highly significant for all yield traits. Variations due to G x E interaction were greater than those due to genotypic differences for all yield traits. Genotype x location x year ...

  8. Isolation of two independent allyl alcohol resistant Adh-1 null mutants following selection of pollen and seeds.

    NARCIS (Netherlands)

    Wisman, E.; Ramanna, M.S.; Zabel, P.

    1993-01-01

    The Adh-1 null mutant (B15-1-8) isolated previously was used to establish conditions that allow the selection of ADH-deficient pollen grains and seeds of tomato. New Adh-1 null mutants were then selected among the progenies derived from crosses between the genetically unstable tomato lines Yvms,

  9. Increased Oocyte Degeneration and Follicular Atresia during the Estrous Cycle in Anti-Müllerian Hormone Null Mice

    NARCIS (Netherlands)

    Visser, Jenny A.; Durlinger, Alexandra L.L.; Peters, Isolde J.J.; Heuvel, Edwin R. van den; Rose, Ursula M.; Kramer, Piet; Jong, Frank H. de; Themmen, Axel P.N.

    2007-01-01

    Anti-Müllerian hormone (AMH) plays an important role in folliculogenesis. AMH null mice display an increased recruitment of primordial follicles. Nevertheless, these mice do not have proportionally more preovulatory follicles. Therefore, AMH null mice provide an interesting genetic model to study

  10. Population estimators or progeny tests: what is the best method to assess null allele frequencies at SSR loci?

    NARCIS (Netherlands)

    Oddou-Muratorio, S.; Vendramin, G.G.; Buiteveld, J.; Fady, B.

    2009-01-01

    Nuclear SSRs are notorious for having relatively high frequencies of null alleles, i.e. alleles that fail to amplify and are thus recessive and undetected in heterozygotes. In this paper, we compare two kinds of approaches for estimating null allele frequencies at seven nuclear microsatellite

  11. Genotyping-by-sequencing data of 272 crested wheatgrass (Agropyron cristatum genotypes

    Directory of Open Access Journals (Sweden)

    Pingchuan Li

    2017-12-01

    Full Text Available Crested wheatgrass [Agropyron cristatum L. (Gaertn.] is an important cool-season forage grass widely used for early spring grazing. However, the genomic resources for this non-model plant are still lacking. Our goal was to generate the first set of next generation sequencing data using the genotyping-by-sequencing technique. A total of 272 crested wheatgrass plants representing seven breeding lines, five cultivars and five geographically diverse accessions were sequenced with an Illumina MiSeq instrument. These sequence datasets were processed using different bioinformatics tools to generate contigs for diploid and tetraploid plants and SNPs for diploid plants. Together, these genomic resources form a fundamental basis for genomic studies of crested wheatgrass and other wheatgrass species. The raw reads were deposited into Sequence Read Archive (SRA database under NCBI accession SRP115373 (https://www.ncbi.nlm.nih.gov/sra?term=SRP115373 and the supplementary datasets are accessible in Figshare (10.6084/m9.figshare.5345092. Keywords: Crested wheatgrass, Genotyping-by-sequencing, Diploid, Tetraploid, Raw sequence data

  12. Genetic Divergence in Sugarcane Genotypes

    OpenAIRE

    Tahir, Mohammad; Rahman, Hidayatur; Gul, Rahmani; Ali, Amjad; Khalid, Muhammad

    2012-01-01

    To assess genetic divergence of sugarcane germplasm, an experiment comprising 25 sugarcane genotypes was conducted at Sugar Crops Research Institute (SCRI), Mardan, Khyber Pakhtunkhwa, Pakistan, in quadruple lattice design during 2008-09. Among the 14 parameters evaluated, majority exhibited significant differences while some showed nonsignificant mean squares. The initial correlation matrix revealed medium to high correlations. Principal Component Analysis (PCA) showed that there were two pr...

  13. On Bäcklund transformation and vortex filament equation for null Cartan curve in Minkowski 3-space

    Energy Technology Data Exchange (ETDEWEB)

    Grbović, Milica, E-mail: milica.grbovic@kg.ac.rs; Nešović, Emilija, E-mail: nesovickg@sbb.rs [University of Kragujevac, Faculty of Science, Department of Mathematics and Informatics (Serbia)

    2016-12-15

    In this paper we introduce Bäcklund transformation of a null Cartan curve in Minkowski 3-space as a transformation which maps a null Cartan helix to another null Cartan helix, congruent to the given one. We also give the sufficient conditions for a transformation between two null Cartan curves in the Minkowski 3-space such that these curves have equal constant torsions. By using the Da Rios vortex filament equation, based on localized induction approximation, we derive the vortex filament equation for a null Cartan curve and obtain evolution equation for it’s torsion. As an application, we show that Cartan’s frame vectors generate new solutions of the Da Rios vortex filament equation.

  14. Population genetics for 23 Y-STR loci in Tibetan in China and confirmation of DYS448 null allele.

    Science.gov (United States)

    Ye, Yi; Gao, Jingshang; Fan, Guangyao; Liao, Linchuan; Hou, Yiping

    2015-05-01

    Tibetan is one of 56 ethnic groups in China, where a level of genetic sub-structure might be expected. Although a global analysis of Y-chromosomal haplotype diversity for 23 STR loci and Y-STR databases with PPY23 kit were created with collaborative effort, there was a lack of data for Tibetan population. In this study we evaluated 248 unrelated male individuals of Chinese Tibetan living in the Tibet Autonomous Region to explore the underlying genetic structure of Tibetan populations. These samples were typed for 23 short-tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, GATAH4, DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643) by using PPY23 kit. A total of 224 different haplotypes were found. Haplotype diversity was 0.9990. Both Rst pairwise analyses and multidimensional scaling plot showed the genetic structure of Tibetan population was significantly different from some of Chinese ethnic groups and neighboring populations. There were few interesting null features at DYS448 observed by PPY23 that deserved some comment. It revealed that PPY23 marker set provided substantially stronger discriminatory power in Tibetan population. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  15. Mitotic catastrophe occurs in the absence of apoptosis in p53-null cells with a defective G1 checkpoint.

    Directory of Open Access Journals (Sweden)

    Michalis Fragkos

    Full Text Available Cell death occurring during mitosis, or mitotic catastrophe, often takes place in conjunction with apoptosis, but the conditions in which mitotic catastrophe may exhibit features of programmed cell death are still unclear. In the work presented here, we studied mitotic cell death by making use of a UV-inactivated parvovirus (adeno-associated virus; AAV that has been shown to induce a DNA damage response and subsequent death of p53-defective cells in mitosis, without affecting the integrity of the host genome. Osteosarcoma cells (U2OSp53DD that are deficient in p53 and lack the G1 cell cycle checkpoint respond to AAV infection through a transient G2 arrest. We found that the infected U2OSp53DD cells died through mitotic catastrophe with no signs of chromosome condensation or DNA fragmentation. Moreover, cell death was independent of caspases, apoptosis-inducing factor (AIF, autophagy and necroptosis. These findings were confirmed by time-lapse microscopy of cellular morphology following AAV infection. The assays used readily revealed apoptosis in other cell types when it was indeed occurring. Taken together the results indicate that in the absence of the G1 checkpoint, mitotic catastrophe occurs in these p53-null cells predominantly as a result of mechanical disruption induced by centrosome overduplication, and not as a consequence of a suicide signal.

  16. Blood group genotyping: from patient to high-throughput donor screening.

    Science.gov (United States)

    Veldhuisen, B; van der Schoot, C E; de Haas, M

    2009-10-01

    Blood group antigens, present on the cell membrane of red blood cells and platelets, can be defined either serologically or predicted based on the genotypes of genes encoding for blood group antigens. At present, the molecular basis of many antigens of the 30 blood group systems and 17 human platelet antigens is known. In many laboratories, blood group genotyping assays are routinely used for diagnostics in cases where patient red cells cannot be used for serological typing due to the presence of auto-antibodies or after recent transfusions. In addition, DNA genotyping is used to support (un)-expected serological findings. Fetal genotyping is routinely performed when there is a risk of alloimmune-mediated red cell or platelet destruction. In case of patient blood group antigen typing, it is important that a genotyping result is quickly available to support the selection of donor blood, and high-throughput of the genotyping method is not a prerequisite. In addition, genotyping of blood donors will be extremely useful to obtain donor blood with rare phenotypes, for example lacking a high-frequency antigen, and to obtain a fully typed donor database to be used for a better matching between recipient and donor to prevent adverse transfusion reactions. Serological typing of large cohorts of donors is a labour-intensive and expensive exercise and hampered by the lack of sufficient amounts of approved typing reagents for all blood group systems of interest. Currently, high-throughput genotyping based on DNA micro-arrays is a very feasible method to obtain a large pool of well-typed blood donors. Several systems for high-throughput blood group genotyping are developed and will be discussed in this review.

  17. Power calculations for likelihood ratio tests for offspring genotype risks, maternal effects, and parent-of-origin (POO) effects in the presence of missing parental genotypes when unaffected siblings are available.

    Science.gov (United States)

    Rampersaud, E; Morris, R W; Weinberg, C R; Speer, M C; Martin, E R

    2007-01-01

    Genotype-based likelihood-ratio tests (LRT) of association that examine maternal and parent-of-origin effects have been previously developed in the framework of log-linear and conditional logistic regression models. In the situation where parental genotypes are missing, the expectation-maximization (EM) algorithm has been incorporated in the log-linear approach to allow incomplete triads to contribute to the LRT. We present an extension to this model which we call the Combined_LRT that incorporates additional information from the genotypes of unaffected siblings to improve assignment of incompletely typed families to mating type categories, thereby improving inference of missing parental data. Using simulations involving a realistic array of family structures, we demonstrate the validity of the Combined_LRT under the null hypothesis of no association and provide power comparisons under varying levels of missing data and using sibling genotype data. We demonstrate the improved power of the Combined_LRT compared with the family-based association test (FBAT), another widely used association test. Lastly, we apply the Combined_LRT to a candidate gene analysis in Autism families, some of which have missing parental genotypes. We conclude that the proposed log-linear model will be an important tool for future candidate gene studies, for many complex diseases where unaffected siblings can often be ascertained and where epigenetic factors such as imprinting may play a role in disease etiology.

  18. Conceptualising the lack of health insurance coverage.

    Science.gov (United States)

    Davis, J B

    2000-01-01

    This paper examines the lack of health insurance coverage in the US as a public policy issue. It first compares the problem of health insurance coverage to the problem of unemployment to show that in terms of the numbers of individuals affected lack of health insurance is a problem comparable in importance to the problem of unemployment. Secondly, the paper discusses the methodology involved in measuring health insurance coverage, and argues that the current method of estimation of the uninsured underestimates the extent that individuals go without health insurance. Third, the paper briefly introduces Amartya Sen's functioning and capabilities framework to suggest a way of representing the extent to which individuals are uninsured. Fourth, the paper sketches a means of operationalizing the Sen representation of the uninsured in terms of the disability-adjusted life year (DALY) measure.

  19. Laura: Soybean variety lacking Kunitz trypsin inhibitor

    Directory of Open Access Journals (Sweden)

    Srebrić Mirjana

    2010-01-01

    Full Text Available Grain of conventional soybean varieties requires heat processing to break down trypsin inhibitor's activity before using as food or animal feed. At the same time, protein denaturation and other qualitative changes occur in soybean grain, especially if the temperature of heating is not controlled. Two types of trypsin inhibitor were found in soybean grain the Kunitz trypsin inhibitor and the Bowman-Birk inhibitor. Mature grain of soybean Laura is lacking Kunitz trypsin inhibitor. Grain yield of variety Laura is equal to high yielding varieties from the maturity group I, where it belongs. Lacking of Kunitz-trypsin inhibitor makes soybean grain suitable for direct feeding in adult non ruminant animals without previous thermal processing. Grain of variety Laura can be processed for a shorter period of time than conventional soybeans. This way we save energy, and preserve valuable nutritional composition of soybean grain, which is of interest in industrial processing.

  20. Communication impairments in mice lacking Shank1: reduced levels of ultrasonic vocalizations and scent marking behavior.

    Directory of Open Access Journals (Sweden)

    Markus Wöhr

    Full Text Available Autism is a neurodevelopmental disorder with a strong genetic component. Core symptoms are abnormal reciprocal social interactions, qualitative impairments in communication, and repetitive and stereotyped patterns of behavior with restricted interests. Candidate genes for autism include the SHANK gene family, as mutations in SHANK2 and SHANK3 have been detected in several autistic individuals. SHANK genes code for a family of scaffolding proteins located in the postsynaptic density of excitatory synapses. To test the hypothesis that a mutation in SHANK1 contributes to the symptoms of autism, we evaluated Shank1(-/- null mutant mice for behavioral phenotypes with relevance to autism, focusing on social communication. Ultrasonic vocalizations and the deposition of scent marks appear to be two major modes of mouse communication. Our findings revealed evidence for low levels of ultrasonic vocalizations and scent marks in Shank1(-/- mice as compared to wildtype Shank1(+/+ littermate controls. Shank1(-/- pups emitted fewer vocalizations than Shank1(+/+ pups when isolated from mother and littermates. In adulthood, genotype affected scent marking behavior in the presence of female urinary pheromones. Adult Shank1(-/- males deposited fewer scent marks in proximity to female urine than Shank1(+/+ males. Call emission in response to female urinary pheromones also differed between genotypes. Shank1(+/+ mice changed their calling pattern dependent on previous female interactions, while Shank1(-/- mice were unaffected, indicating a failure of Shank1(-/- males to learn from a social experience. The reduced levels of ultrasonic vocalizations and scent marking behavior in Shank1(-/- mice are consistent with a phenotype relevant to social communication deficits in autism.

  1. Communication Impairments in Mice Lacking Shank1: Reduced Levels of Ultrasonic Vocalizations and Scent Marking Behavior

    Science.gov (United States)

    Wöhr, Markus; Roullet, Florence I.; Hung, Albert Y.; Sheng, Morgan; Crawley, Jacqueline N.

    2011-01-01

    Autism is a neurodevelopmental disorder with a strong genetic component. Core symptoms are abnormal reciprocal social interactions, qualitative impairments in communication, and repetitive and stereotyped patterns of behavior with restricted interests. Candidate genes for autism include the SHANK gene family, as mutations in SHANK2 and SHANK3 have been detected in several autistic individuals. SHANK genes code for a family of scaffolding proteins located in the postsynaptic density of excitatory synapses. To test the hypothesis that a mutation in SHANK1 contributes to the symptoms of autism, we evaluated Shank1 −/− null mutant mice for behavioral phenotypes with relevance to autism, focusing on social communication. Ultrasonic vocalizations and the deposition of scent marks appear to be two major modes of mouse communication. Our findings revealed evidence for low levels of ultrasonic vocalizations and scent marks in Shank1 −/− mice as compared to wildtype Shank1 +/+ littermate controls. Shank1 −/− pups emitted fewer vocalizations than Shank1+/+ pups when isolated from mother and littermates. In adulthood, genotype affected scent marking behavior in the presence of female urinary pheromones. Adult Shank1 −/− males deposited fewer scent marks in proximity to female urine than Shank1+/+ males. Call emission in response to female urinary pheromones also differed between genotypes. Shank1+/+ mice changed their calling pattern dependent on previous female interactions, while Shank1 −/− mice were unaffected, indicating a failure of Shank1 −/− males to learn from a social experience. The reduced levels of ultrasonic vocalizations and scent marking behavior in Shank1 −/− mice are consistent with a phenotype relevant to social communication deficits in autism. PMID:21695253

  2. Very high resolution single pass HLA genotyping using amplicon sequencing on the 454 next generation DNA sequencers: Comparison with Sanger sequencing.

    Science.gov (United States)

    Yamamoto, F; Höglund, B; Fernandez-Vina, M; Tyan, D; Rastrou, M; Williams, T; Moonsamy, P; Goodridge, D; Anderson, M; Erlich, H A; Holcomb, C L

    2015-12-01

    Compared to Sanger sequencing, next-generation sequencing offers advantages for high resolution HLA genotyping including increased throughput, lower cost, and reduced genotype ambiguity. Here we describe an enhancement of the Roche 454 GS GType HLA genotyping assay to provide very high resolution (VHR) typing, by the addition of 8 primer pairs to the original 14, to genotype 11 HLA loci. These additional amplicons help resolve common and well-documented alleles and exclude commonly found null alleles in genotype ambiguity strings. Simplification of workflow to reduce the initial preparation effort using early pooling of amplicons or the Fluidigm Access Array™ is also described. Performance of the VHR assay was evaluated on 28 well characterized cell lines using Conexio Assign MPS software which uses genomic, rather than cDNA, reference sequence. Concordance was 98.4%; 1.6% had no genotype assignment. Of concordant calls, 53% were unambiguous. To further assess the assay, 59 clinical samples were genotyped and results compared to unambiguous allele assignments obtained by prior sequence-based typing supplemented with SSO and/or SSP. Concordance was 98.7% with 58.2% as unambiguous calls; 1.3% could not be assigned. Our results show that the amplicon-based VHR assay is robust and can replace current Sanger methodology. Together with software enhancements, it has the potential to provide even higher resolution HLA typing. Copyright © 2015. Published by Elsevier Inc.

  3. Inhibition of urethane-induced genotoxicity and cell proliferation in CYP2E1-null mice

    International Nuclear Information System (INIS)

    Hoffler, Undi; Dixon, Darlene; Peddada, Shyamal; Ghanayem, Burhan I.

    2005-01-01

    Urethane is a multi-site animal carcinogen and was classified as 'reasonably anticipated to be a human carcinogen.' Urethane is a fermentation by-product and found at appreciable levels in alcoholic beverages and foods such as bread and cheese. Recent work in this laboratory demonstrated for the first time that CYP2E1 is the principal enzyme responsible for urethane metabolism. The current studies were undertaken to assess the relationships between CYP2E1-mediated metabolism and urethane-induced genotoxicity and cell proliferation as determined by induction of micronucleated erythrocytes (MN) and expression of Ki-67, respectively, using CYP2E1-null and wild-type mice. Urethane was administered at 0 (vehicle), 1, 10, or 100 mg/kg/day (p.o.), 5 days/week for 6 weeks. A significant dose-dependent increase in MN was observed in wild-type mice; however, a slight increase was measured in the MN-polychromatic erythrocytes in CYP2E1-null mice treated with 100 mg/kg. A significant increase in the expression of Ki-67 was detected in the livers and the lungs (terminal bronchioles, alveoli, and bronchi) of wild-type mice administered 100 mg urethane/kg in comparison to controls. In contrast, CYP2E1-null mice administered this dose exhibited negligible alterations in Ki-67 expression in the livers and lungs compared to controls. Interestingly, while Ki-67 expression in the forestomach decreased in wild-type mice, it increased in CYP2E1-null mice. Subsequent comparative metabolism studies demonstrated that total urethane-derived radioactivity in the plasma, liver, and lung was significantly higher in CYP2E1-null versus wild-type mice and un-metabolized urethane constituted greater than 83% of the radioactivity in CYP2E1-null mice. Un-metabolized urethane was not detectable in the plasma, liver, and lung of wild-type mice. In conclusion, these data demonstrated that CYP2E1-mediated metabolism of urethane, presumably via epoxide formation, is necessary for the induction of

  4. Comparative proteomic analysis of normal and collagen IX null mouse cartilage reveals altered extracellular matrix composition and novel components of the collagen IX interactome.

    Science.gov (United States)

    Brachvogel, Bent; Zaucke, Frank; Dave, Keyur; Norris, Emma L; Stermann, Jacek; Dayakli, Münire; Koch, Manuel; Gorman, Jeffrey J; Bateman, John F; Wilson, Richard

    2013-05-10

    , whereas matrilin-4 was verified as a novel collagen IX-binding protein. Furthermore, changes in TGFβ-induced protein βig-h3 and fibronectin abundance were found in the collagen IX knock-out but not associated with COMP ablation, indicating specific involvement in the abnormal collagen IX null cartilage. In addition, the more widespread expression of collagen XII in the collagen IX-deficient cartilage suggests an attempted compensatory response to the absence of collagen IX. Our differential proteomic analysis of cartilage is a novel approach to identify candidate matrix protein interactions in vivo, underpinning further analysis of mutant cartilage lacking other matrix components or harboring disease-causing mutations.

  5. Accidents in radiotherapy: Lack of quality assurance?

    International Nuclear Information System (INIS)

    Novotny, J.

    1997-01-01

    About 150 radiological accidents, involving more than 3000 patients with adverse effects, 15 patient's fatalities and about 5000 staff and public exposures have been collected and analysed. Out of 67 analysed accidents in external beam therapy 22% has been caused by wrong calculation of the exposure time or monitor units, 13% by inadequate review of patient's chart, 12% by mistakes in the anatomical area to be treated. The remaining 35% can be attributed to 17 different causes. The most common mistakes in brachytherapy were wrong activities of sources used for treatment (20%), inadequate procedures for placement of sources applicators (14%), mistakes in calculating the treatment time (12%), etc. The direct and contributing causes of radiological accidents have been deduced from each event, when it was possible and categorized into 9 categories: mistakes in procedures (30%), professional mistakes (17%), communication mistakes (15%), lack of training (8.5%), interpretation mistakes (7%), lack of supervision (6%), mistakes in judgement (6%), hardware failures (5%), software and other mistakes (5.5%). Three types of direct and contributing causes responsible for almost 62% of all accidents are directly connected to the quality assurance of treatment. The lessons learnt from the accidents are related to frequencies of direct and contributing factors and show that most of the accident are caused by lack, non-application of quality assurance (QA) procedures or by underestimating of QA procedures. The international system for collection of accidents and dissemination of lessons learnt from the different accidents, proposed by IAEA, can contribute to better practice in many radiotherapy departments. Most of the accidents could have been avoided, had a comprehensive QA programme been established and properly applied in all radiotherapy departments, whatever the size. (author)

  6. Why does Colombia lack agricultural commodity futures?

    Directory of Open Access Journals (Sweden)

    Pablo Moreno-Alemay

    2015-11-01

    Full Text Available This article explores the reasons why futures contracts are not traded as an alternative to price hedging for agricultural goods in Colombia. Based on surveys, interviews and statistical analysis, this study identified that conceptual gaps in contract negotiation, lack of consensus in the agricultural sector regarding the use of financial mechanisms and the sector’s infrequent contact with Colombia’s financial institutions, are the main reasons why a futures contracts market has not emerged.

  7. Null geodesics and wave front singularities in the Gödel space-time

    Science.gov (United States)

    Kling, Thomas P.; Roebuck, Kevin; Grotzke, Eric

    2018-01-01

    We explore wave fronts of null geodesics in the Gödel metric emitted from point sources both at, and away from, the origin. For constant time wave fronts emitted by sources away from the origin, we find cusp ridges as well as blue sky metamorphoses where spatially disconnected portions of the wave front appear, connect to the main wave front, and then later break free and vanish. These blue sky metamorphoses in the constant time wave fronts highlight the non-causal features of the Gödel metric. We introduce a concept of physical distance along the null geodesics, and show that for wave fronts of constant physical distance, the reorganization of the points making up the wave front leads to the removal of cusp ridges.

  8. Luxembourg in the Early Days of the EEC: Null Player or Not?

    Directory of Open Access Journals (Sweden)

    Alexander Mayer

    2018-05-01

    Full Text Available Voters whose yes-or-no decision never makes a difference to the outcome in a simple voting game are known as “null players”. Luxembourg’s role in the Council of Ministers during the first period of the European Economic Community (EEC is often cited as a real-world case. The paper contrasts the textbook claim that Luxembourg was a null player with a more comprehensive picture of Luxembourg’s role in EEC’s voting system. The assessment of Luxembourg’s voting power is sensitive to the role played by the European Commission in the decision-making procedure and the measurement concepts underlying power evaluations.

  9. Enhanced endotoxin sensitivity in fps/fes-null mice with minimal defects in hematopoietic homeostasis.

    Science.gov (United States)

    Zirngibl, Ralph A; Senis, Yotis; Greer, Peter A

    2002-04-01

    The fps/fes proto-oncogene encodes a cytoplasmic protein tyrosine kinase implicated in growth factor and cytokine receptor signaling and thought to be essential for the survival and terminal differentiation of myeloid progenitors. Fps/Fes-null mice were healthy and fertile, displayed slightly reduced numbers of bone marrow myeloid progenitors and circulating mature myeloid cells, and were more sensitive to lipopolysaccharide (LPS). These phenotypes were rescued using a fps/fes transgene. This confirmed that Fps/Fes is involved in, but not required for, myelopoiesis and that it plays a role in regulating the innate immune response. Bone marrow-derived Fps/Fes-null macrophages showed no defects in granulocyte-macrophage colony-stimulating factor-, interleukin 6 (IL-6)-, or IL-3-induced activation of signal transducer and activator of transcription 3 (Stat3) and Stat5A or LPS-induced degradation of I kappa B or activation of p38, Jnk, Erk, or Akt.

  10. Magnetic Nulls and Super-radial Expansion in the Solar Corona

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, Sarah E.; Dalmasse, Kevin; Tomczyk, Steven; Toma, Giuliana de; Burkepile, Joan; Galloy, Michael [National Center for Atmospheric Research, 3080 Center Green Drive, Boulder, CO 80301 (United States); Rachmeler, Laurel A. [NASA Marshall Space Flight Center, Huntsville, AL 35811 (United States); Rosa, Marc L. De, E-mail: sgibson@ucar.edu [Lockheed Martin Solar and Astrophysics Laboratory, 3251 Hanover Street B/252, Palo Alto, CA 94304 (United States)

    2017-05-10

    Magnetic fields in the Sun’s outer atmosphere—the corona—control both solar-wind acceleration and the dynamics of solar eruptions. We present the first clear observational evidence of coronal magnetic nulls in off-limb linearly polarized observations of pseudostreamers, taken by the Coronal Multichannel Polarimeter (CoMP) telescope. These nulls represent regions where magnetic reconnection is likely to act as a catalyst for solar activity. CoMP linear-polarization observations also provide an independent, coronal proxy for magnetic expansion into the solar wind, a quantity often used to parameterize and predict the solar wind speed at Earth. We introduce a new method for explicitly calculating expansion factors from CoMP coronal linear-polarization observations, which does not require photospheric extrapolations. We conclude that linearly polarized light is a powerful new diagnostic of critical coronal magnetic topologies and the expanding magnetic flux tubes that channel the solar wind.

  11. Local differential geometry of null curves in conformally flat space-time

    International Nuclear Information System (INIS)

    Urbantke, H.

    1989-01-01

    The conformally invariant differential geometry of null curves in conformally flat space-times is given, using the six-vector formalism which has generalizations to higher dimensions. This is then paralleled by a twistor description, with a twofold merit: firstly, sometimes the description is easier in twistor terms, sometimes in six-vector terms, which leads to a mutual enlightenment of both; and secondly, the case of null curves in timelike pseudospheres or 2+1 Minkowski space we were only able to treat twistorially, making use of an invariant differential found by Fubini and Cech. The result is the expected one: apart from stated exceptional cases there is a conformally invariant parameter and two conformally invariant curvatures which, when specified in terms of this parameter, serve to characterize the curve up to conformal transformations. 12 refs. (Author)

  12. Bursty, Broadband Electromagnetic Waves Associated with Three-Dimensional Nulls Observed in Turbulent Magnetosheath Reconnection

    Science.gov (United States)

    Adrian, Mark L.; Wendel, D. E.

    2012-01-01

    We investigate observations of intense bursts of electromagnetic wave energy in association with the thin current layers of turbulent magnetosheath reconnection. These observed emissions - typically detected in the layers immediately outside of the current layer proper - form two distinct types: (i) broadband emissions that extend continuously to lOs of Hertz; and (ii) structured bursts of emitted energy that occur above 80-Hz, often displaying features reminiscent of absorption bands and are observed near the local minima in the magnetic field. We present detailed analyses of these intense bursts of electromagnetic energy and quantify their proximity to X-IO-nulls and magnetic spine connected null pairs, as well as their correlation - if any - to the amount of magnetic energy converted by the process of magnetic reconnection.

  13. Vacuum solutions admitting a geodesic null congruence with shear proportional to expansion

    International Nuclear Information System (INIS)

    Kupeli, A.H.

    1988-01-01

    Algebraically general, nontwisting solutions for the vacuum to vacuum generalized Kerr--Schild (GKS) transformation are obtained. These solutions admit a geodesic null congruence with shear proportional to expansion. In the Newman--Penrose formalism, if l/sup μ/ is chosen to be the null vector of the GKS transformation, this property is stated as σ = arho and Da = 0. It is assumed that a is a constant, and the background is chosen as a pp-wave solution. For generic values of a, the GKS metrics consist of the Kasner solutions. For a = +- (1 +- (2)/sup 1/2/), there are solutions with less symmetries including special cases of the Kota--Perjes and Lukacs solutions

  14. Kinetic modeling of particle acceleration in a solar null point reconnection region

    DEFF Research Database (Denmark)

    Baumann, Gisela; Haugbølle, Troels; Nordlund, Åke

    2013-01-01

    The primary focus of this paper is on the particle acceleration mechanism in solar coronal 3D reconnection null-point regions. Starting from a potential field extrapolation of a SOHO magnetogram taken on 2002 November 16, we first performed MHD simulations with horizontal motions observed by SOHO...... particles and 3.5 billion grid cells of size 17.5\\,km --- these simulations offer a new opportunity to study particle acceleration in solar-like settings....... applied to the photospheric boundary of the computational box. After a build-up of electric current in the fan-plane of the null-point, a sub-section of the evolved MHD data was used as initial and boundary conditions for a kinetic particle-in-cell model of the plasma. We find that sub...

  15. IMPROVING INTERFEROMETRIC NULL DEPTH MEASUREMENTS USING STATISTICAL DISTRIBUTIONS: THEORY AND FIRST RESULTS WITH THE PALOMAR FIBER NULLER

    International Nuclear Information System (INIS)

    Hanot, C.; Riaud, P.; Absil, O.; Mennesson, B.; Martin, S.; Liewer, K.; Loya, F.; Mawet, D.; Serabyn, E.

    2011-01-01

    A new 'self-calibrated' statistical analysis method has been developed for the reduction of nulling interferometry data. The idea is to use the statistical distributions of the fluctuating null depth and beam intensities to retrieve the astrophysical null depth (or equivalently the object's visibility) in the presence of fast atmospheric fluctuations. The approach yields an accuracy much better (about an order of magnitude) than is presently possible with standard data reduction methods, because the astrophysical null depth accuracy is no longer limited by the magnitude of the instrumental phase and intensity errors but by uncertainties on their probability distributions. This approach was tested on the sky with the two-aperture fiber nulling instrument mounted on the Palomar Hale telescope. Using our new data analysis approach alone-and no observations of calibrators-we find that error bars on the astrophysical null depth as low as a few 10 -4 can be obtained in the near-infrared, which means that null depths lower than 10 -3 can be reliably measured. This statistical analysis is not specific to our instrument and may be applicable to other interferometers.

  16. Genotyping of Canine parvovirus in western Mexico.

    Science.gov (United States)

    Pedroza-Roldán, César; Páez-Magallan, Varinia; Charles-Niño, Claudia; Elizondo-Quiroga, Darwin; De Cervantes-Mireles, Raúl Leonel; López-Amezcua, Mario Alberto

    2015-01-01

    Canine parvovirus (CPV) is one of the most common infectious agents related to high morbidity rates in dogs. In addition, the virus is associated with severe gastroenteritis, diarrhea, and vomiting, resulting in high death rates, especially in puppies and nonvaccinated dogs. To date, there are 3 variants of the virus (CPV-2a, CPV-2b, and CPV-2c) circulating worldwide. In Mexico, reports describing the viral variants circulating in dog populations are lacking. In response to this deficiency, a total of 41 fecal samples of suspected dogs were collected from October 2013 through April 2014 in the Veterinary Hospital of the University of Guadalajara in western Mexico. From these, 24 samples resulted positive by polymerase chain reaction, and the viral variant was determined by restriction fragment length polymorphism. Five positive diagnosed samples were selected for partial sequencing of the vp2 gene and codon analysis. The results demonstrated that the current dominant viral variant in Mexico is CPV-2c. The current study describes the genotyping of CPV strains, providing valuable evidence of the dominant frequency of this virus in a dog population from western Mexico. © 2014 The Author(s).

  17. Generation of recombinant European bat lyssavirus type 1 and inter-genotypic compatibility of lyssavirus genotype 1 and 5 antigenome promoters.

    Science.gov (United States)

    Orbanz, Jeannette; Finke, Stefan

    2010-10-01

    Bat lyssaviruses (Fam. Rhabdoviridae) represent a source for the infection of terrestial mammals and the development of rabies disease. Molecular differences in the replication of bat and non-bat lyssaviruses and their contribution to pathogenicity, however, are unknown. One reason for this is the lack of reverse genetics systems for bat-restricted lyssaviruses. To investigate bat lyssavirus replication and host adaptation, we developed a reverse genetics system for European bat lyssavirus type 1 (EBLV-1; genotype 5). This was achieved by co-transfection of HEK-293T cells with a full-length EBLV-1 genome cDNA and expression plasmids for EBLV-1 proteins, resulting in recombinant EBLV-1 (rEBLV-1). Replication of rEBLV-1 was comparable to that of parental virus, showing that rEBLV-1 is a valid tool to investigate EBLV-1 replication functions. In a first approach, we tested whether the terminal promoter sequences of EBLV-1 are genotype-specific. Although genotype 1 (rabies virus) minigenomes were successfully amplified by EBLV-1 helper virus, in the context of the complete virus, only the antigenome promoter (AGP) sequence of EBLV-1 was replaceable, as indicated by comparable replication of rEBLV-1 and the chimeric virus. These analyses demonstrate that the terminal AGPs of genotype 1 and genotype 5 lyssaviruses are compatible with those of the heterologous genotype.

  18. A mycobacterial smc null mutant is proficient in DNA repair and long-term survival.

    Science.gov (United States)

    Güthlein, Carolin; Wanner, Roger M; Sander, Peter; Böttger, Erik C; Springer, Burkhard

    2008-01-01

    SMC (structural maintenance of chromosomes) proteins play fundamental roles in various aspects of chromosome organization and dynamics, including repair of DNA damage. Mutant strains of Mycobacterium smegmatis and Mycobacterium tuberculosis defective in SMC were constructed. Surprisingly, inactivation of smc did not result in recognizable phenotypes in hallmark assays characteristic for the function of these genes. This is in contrast to data for smc null mutants in other species.

  19. A Mycobacterial smc Null Mutant Is Proficient in DNA Repair and Long-Term Survival▿

    OpenAIRE

    Güthlein, Carolin; Wanner, Roger M.; Sander, Peter; Böttger, Erik C.; Springer, Burkhard

    2007-01-01

    SMC (structural maintenance of chromosomes) proteins play fundamental roles in various aspects of chromosome organization and dynamics, including repair of DNA damage. Mutant strains of Mycobacterium smegmatis and Mycobacterium tuberculosis defective in SMC were constructed. Surprisingly, inactivation of smc did not result in recognizable phenotypes in hallmark assays characteristic for the function of these genes. This is in contrast to data for smc null mutants in other species.

  20. Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation

    Directory of Open Access Journals (Sweden)

    Timothy M. Adamo

    2009-09-01

    Full Text Available A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in complex Minkowski space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss by (Bondi’s integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum–conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

  1. Potential of balloon payloads for in flight validation of direct and nulling interferometry concepts

    Science.gov (United States)

    Demangeon, Olivier; Ollivier, Marc; Le Duigou, Jean-Michel; Cassaing, Frédéric; Coudé du Foresto, Vincent; Mourard, Denis; Kern, Pierre; Lam Trong, Tien; Evrard, Jean; Absil, Olivier; Defrere, Denis; Lopez, Bruno

    2010-07-01

    While the question of low cost / low science precursors is raised to validate the concepts of direct and nulling interferometry space missions, balloon payloads offer a real opportunity thanks to their relatively low cost and reduced development plan. Taking into account the flight capabilities of various balloon types, we propose in this paper, several concepts of payloads associated to their flight plan. We also discuss the pros and cons of each concepts in terms of technological and science demonstration power.

  2. Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta

    Czech Academy of Sciences Publication Activity Database

    Zahradníček, Oldřich; Horáček, I.; Tucker, A. S.

    2012-01-01

    Roč. 221, č. 3 (2012), s. 195-208 ISSN 0021-8782 R&D Projects: GA ČR(CZ) GAP305/12/1766 Grant - others:GA AV ČR(CZ) KJB601110910 Program:KJ Institutional research plan: CEZ:AV0Z50390703 Institutional support: RVO:68378041 Keywords : cusps * gecko * null generation teeth Subject RIV: EA - Cell Biology Impact factor: 2.357, year: 2012

  3. Vascular Response to Intra-arterial Injury in the Thrombospondin-1 Null Mouse

    OpenAIRE

    Budhani, Faisal; Leonard, Katherine A.; Bergdahl, Andreas; Gao, Jimin; Lawler, Jack; Davis, Elaine C.

    2007-01-01

    Thrombospondin-1 (TSP-1) is a multifunctional, extracellular matrix protein that has been implicated in the regulation of smooth muscle cell proliferation, migration and differentiation during vascular development and injury. Vascular injury in wildtype and TSP-1 null mice was carried out by insertion of a straight spring guidewire into the femoral artery via a muscular arterial branch. Blood flow was restored after the muscular branch was ligated. The injury completely denuded the endotheliu...

  4. Null strings and complex Einstein-Maxwell fields with cosmological constant

    International Nuclear Information System (INIS)

    Garcia, A.; Plebanski, J.F.; Robinson, I.

    1977-01-01

    Previous results of Plebanski and Robinson (Phys. Rev. Lett.; 37:493 (1976)) concerning left-degenerate Einstein-flat complex space-times and preliminary results concerning the electromagnetic field, are here generalized and worked out in some detail for the system of Einstein-Maxwell equations with a cosmological constant. On the assumption that there exists a congruence of totally null surfaces, the system is reduced to a pair of equations for the two unknown functions. (author)

  5. The root infinitive stage in a null subject language: Romance in the Balkans

    Directory of Open Access Journals (Sweden)

    Larisa Avram

    2007-01-01

    Full Text Available The aim of the present paper is to determine which early non-finite verbal form is the Root Infinitive analogue in Romanian, an Inflection-licensed null subject language. In particular, we investigate whether the RI-analogue is the imperative, as predicted by Salustri and Hyams’s (2003 hypothesis, or whether it is a language specific underspecified form, overused during the early stages of acquisition, as predicted by Wexler et al. (2004.

  6. Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation

    Directory of Open Access Journals (Sweden)

    Timothy M. Adamo

    2012-01-01

    Full Text Available A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in an auxiliary four-complex dimensional space, H-space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss by (Bondi's integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum--conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

  7. Likelihood of Null Effects of Large NHLBI Clinical Trials Has Increased over Time.

    Directory of Open Access Journals (Sweden)

    Robert M Kaplan

    Full Text Available We explore whether the number of null results in large National Heart Lung, and Blood Institute (NHLBI funded trials has increased over time.We identified all large NHLBI supported RCTs between 1970 and 2012 evaluating drugs or dietary supplements for the treatment or prevention of cardiovascular disease. Trials were included if direct costs >$500,000/year, participants were adult humans, and the primary outcome was cardiovascular risk, disease or death. The 55 trials meeting these criteria were coded for whether they were published prior to or after the year 2000, whether they registered in clinicaltrials.gov prior to publication, used active or placebo comparator, and whether or not the trial had industry co-sponsorship. We tabulated whether the study reported a positive, negative, or null result on the primary outcome variable and for total mortality.17 of 30 studies (57% published prior to 2000 showed a significant benefit of intervention on the primary outcome in comparison to only 2 among the 25 (8% trials published after 2000 (χ2=12.2,df= 1, p=0.0005. There has been no change in the proportion of trials that compared treatment to placebo versus active comparator. Industry co-sponsorship was unrelated to the probability of reporting a significant benefit. Pre-registration in clinical trials.gov was strongly associated with the trend toward null findings.The number NHLBI trials reporting positive results declined after the year 2000. Prospective declaration of outcomes in RCTs, and the adoption of transparent reporting standards, as required by clinicaltrials.gov, may have contributed to the trend toward null findings.

  8. Null Geodesic Congruences, Asymptotically-Flat Spacetimes and Their Physical Interpretation.

    Science.gov (United States)

    Adamo, Timothy M; Newman, Ezra T; Kozameh, Carlos

    2012-01-01

    A priori, there is nothing very special about shear-free or asymptotically shear-free null geodesic congruences. Surprisingly, however, they turn out to possess a large number of fascinating geometric properties and to be closely related, in the context of general relativity, to a variety of physically significant effects. It is the purpose of this paper to try to fully develop these issues. This work starts with a detailed exposition of the theory of shear-free and asymptotically shear-free null geodesic congruences, i.e., congruences with shear that vanishes at future conformal null infinity. A major portion of the exposition lies in the analysis of the space of regular shear-free and asymptotically shear-free null geodesic congruences. This analysis leads to the space of complex analytic curves in an auxiliary four-complex dimensional space, [Formula: see text]-space. They in turn play a dominant role in the applications. The applications center around the problem of extracting interior physical properties of an asymptotically-flat spacetime directly from the asymptotic gravitational (and Maxwell) field itself, in analogy with the determination of total charge by an integral over the Maxwell field at infinity or the identification of the interior mass (and its loss) by (Bondi's) integrals of the Weyl tensor, also at infinity. More specifically, we will see that the asymptotically shear-free congruences lead us to an asymptotic definition of the center-of-mass and its equations of motion. This includes a kinematic meaning, in terms of the center-of-mass motion, for the Bondi three-momentum. In addition, we obtain insights into intrinsic spin and, in general, angular momentum, including an angular-momentum-conservation law with well-defined flux terms. When a Maxwell field is present, the asymptotically shear-free congruences allow us to determine/define at infinity a center-of-charge world line and intrinsic magnetic dipole moment.

  9. Hypersensitivities for Acetaldehyde and Other Agents among Cancer Cells Null for Clinically Relevant Fanconi Anemia Genes

    OpenAIRE

    Ghosh, Soma; Sur, Surojit; Yerram, Sashidhar R.; Rago, Carlo; Bhunia, Anil K.; Hossain, M. Zulfiquer; Paun, Bogdan C.; Ren, Yunzhao R.; Iacobuzio-Donahue, Christine A.; Azad, Nilofer A.; Kern, Scott E.

    2014-01-01

    Large-magnitude numerical distinctions (>10-fold) among drug responses of genetically contrasting cancers were crucial for guiding the development of some targeted therapies. Similar strategies brought epidemiological clues and prevention goals for genetic diseases. Such numerical guides, however, were incomplete or low magnitude for Fanconi anemia pathway (FANC) gene mutations relevant to cancer in FANC-mutation carriers (heterozygotes). We generated a four-gene FANC-null cancer panel, inclu...

  10. Congruences of null strings in complex space-times and some Cauchy--Kovalevski-like problems

    International Nuclear Information System (INIS)

    Robinson, I.; Rozga, K.

    1984-01-01

    It is shown that a problem of construction of a local congruence of null strings is equivalent to a natural Cauchy--Kovalevski-like problem, related to an equation for a spinor field k/sub A/ defining the congruence. Initial data are specified on two-dimensional submanifolds. In left-conformally-flat spaces, the solution of that problem exists for arbitrary initial data

  11. Chronic Toxoplasma gondii in Nurr1-Null Heterozygous Mice Exacerbates Elevated Open Field Activity

    OpenAIRE

    Eells, Jeffrey B.; Varela-Stokes, Andrea; Guo-Ross, Shirley X.; Kummari, Evangel; Smith, Holly M.; Cox, Erin; Lindsay, David S.

    2015-01-01

    Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population) and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%), genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/-) mice and wild-type (+/+) mice were evaluate using an emergence test, activity in an open fie...

  12. On the dependence of energy confinement on elongation in Single Null divertor plasmas

    International Nuclear Information System (INIS)

    Weisen, H.; Martin, Y.; Moret, J. M.; Others

    2002-03-01

    An analysis of the effect of magnetic geometry on heat flux in a wide range of Single Null diverted discharge configurations with 1.5 κ ∼ 74, based on the configurations in the study. This is very close to dependences from the ITER database for discharge conditions, such as ELMy H-modes, obtained from a large number of experiments in various tokamak devices. (author)

  13. Bi-dimensional null model analysis of presence-absence binary matrices.

    Science.gov (United States)

    Strona, Giovanni; Ulrich, Werner; Gotelli, Nicholas J

    2018-01-01

    Comparing the structure of presence/absence (i.e., binary) matrices with those of randomized counterparts is a common practice in ecology. However, differences in the randomization procedures (null models) can affect the results of the comparisons, leading matrix structural patterns to appear either "random" or not. Subjectivity in the choice of one particular null model over another makes it often advisable to compare the results obtained using several different approaches. Yet, available algorithms to randomize binary matrices differ substantially in respect to the constraints they impose on the discrepancy between observed and randomized row and column marginal totals, which complicates the interpretation of contrasting patterns. This calls for new strategies both to explore intermediate scenarios of restrictiveness in-between extreme constraint assumptions, and to properly synthesize the resulting information. Here we introduce a new modeling framework based on a flexible matrix randomization algorithm (named the "Tuning Peg" algorithm) that addresses both issues. The algorithm consists of a modified swap procedure in which the discrepancy between the row and column marginal totals of the target matrix and those of its randomized counterpart can be "tuned" in a continuous way by two parameters (controlling, respectively, row and column discrepancy). We show how combining the Tuning Peg with a wise random walk procedure makes it possible to explore the complete null space embraced by existing algorithms. This exploration allows researchers to visualize matrix structural patterns in an innovative bi-dimensional landscape of significance/effect size. We demonstrate the rational and potential of our approach with a set of simulated and real matrices, showing how the simultaneous investigation of a comprehensive and continuous portion of the null space can be extremely informative, and possibly key to resolving longstanding debates in the analysis of ecological

  14. Null Geodesics and Strong Field Gravitational Lensing in a String Cloud Background

    International Nuclear Information System (INIS)

    Iftikhar, Sehrish; Sharif, M.

    2015-01-01

    This paper is devoted to studying two interesting issues of a black hole with string cloud background. Firstly, we investigate null geodesics and find unstable orbital motion of particles. Secondly, we calculate deflection angle in strong field limit. We then find positions, magnifications, and observables of relativistic images for supermassive black hole at the galactic center. We conclude that string parameter highly affects the lensing process and results turn out to be quite different from the Schwarzschild black hole

  15. Restoration of Lepr in β cells of Lepr null mice does not prevent hyperinsulinemia and hyperglycemia

    Directory of Open Access Journals (Sweden)

    Anna M. D'souza

    2017-06-01

    Full Text Available Objective: The adipose-derived hormone leptin plays an important role in regulating body weight and glucose homeostasis. Leptin receptors are expressed in the central nervous system as well as peripheral tissues involved in regulating glucose homeostasis, including insulin-producing β cells of the pancreas. Previous studies assessing the role of leptin receptors in β cells used Cre-loxP to disrupt the leptin receptor gene (Lepr in β cells, but variable results were obtained. Furthermore, recombination of Lepr was observed in the hypothalamus or exocrine pancreas, in addition to the β cells, and Lepr in non-β cells may have compensated for the loss of Lepr in β cells, thus making it difficult to assess the direct effects of Lepr in β cells. To determine the significance of Lepr exclusively in β cells, we chose to selectively restore Lepr in β cells of Lepr null mice (LeprloxTB/loxTB. Materials and methods: We used a mouse model in which endogenous expression of Lepr was disrupted by a loxP-flanked transcription blocker (LeprloxTB/loxTB, but was restored by Cre recombinase knocked into the Ins1 gene, which is specifically expressed in β cells (Ins1Cre. We bred LeprloxTB/loxTB and Ins1Cre mice to generate LeprloxTB/loxTB and LeprloxTB/loxTB Ins1Cre mice, as well as Leprwt/wt and Leprwt/wt Ins1Cre littermate mice. Male and female mice were weighed weekly between 6 and 11 weeks of age and fasting blood glucose was measured during this time. Oral glucose was administered to mice aged 7–12 weeks to assess glucose tolerance and insulin secretion. Relative β and α cell area and islet size were also assessed by immunostaining and analysis of pancreas sections of 12–14 week old mice. Results: Male and female LeprloxTB/loxTB mice, lacking whole-body expression of Lepr, had a phenotype similar to db/db mice characterized by obesity, hyperinsulinemia, glucose intolerance, and impaired glucose stimulated insulin secretion. Despite restoring

  16. On the Penrose inequality for dust null shells in the Minkowski spacetime of arbitrary dimension

    International Nuclear Information System (INIS)

    Mars, Marc; Soria, Alberto

    2012-01-01

    A particular, yet relevant, case of the Penrose inequality involves null shells propagating in the Minkowski spacetime. Despite previous claims in the literature, the validity of this inequality remains open. In this paper, we rewrite this inequality in terms of the geometry of the surface obtained by intersecting the past null cone of the original surface S with a constant time hyperplane and the 'time height' function of S over this hyperplane. We also specialize to the case when S lies in the past null cone of a point and show the validity of the corresponding inequality in any dimension (in four dimensions this inequality was proved by Tod (1985 Class. Quantum Grav. 2 L65-8). Exploiting properties of convex hypersurfaces in the Euclidean space, we write down the Penrose inequality in the Minkowski spacetime of an arbitrary dimension n + 2 as an inequality for two smooth functions on the sphere S n . We finally obtain a sufficient condition for the validity of the Penrose inequality in the four-dimensional Minkowski spacetime and show that this condition is satisfied by a large class of surfaces. (paper)

  17. A robust null hypothesis for the potential causes of megadrought in western North America

    Science.gov (United States)

    Ault, T.; St George, S.; Smerdon, J. E.; Coats, S.; Mankin, J. S.; Cruz, C. C.; Cook, B.; Stevenson, S.

    2017-12-01

    The western United States was affected by several megadroughts during the last 1200 years, most prominently during the Medieval Climate Anomaly (MCA: 800 to 1300 CE). A null hypothesis is developed to test the possibility that, given a sufficiently long period of time, these events are inevitable and occur purely as a consequence of internal climate variability. The null distribution of this hypothesis is populated by a linear inverse model (LIM) constructed from global sea-surface temperature anomalies and self-calibrated Palmer Drought Severity Index data for North America. Despite being trained only on seasonal data from the late 20th century, the LIM produces megadroughts that are comparable in their duration, spatial scale, and magnitude as the most severe events of the last 12 centuries. The null hypothesis therefore cannot be rejected with much confidence when considering these features of megadrought, meaning that similar events are possible today, even without any changes to boundary conditions. In contrast, the observed clustering of megadroughts in the MCA, as well as the change in mean hydroclimate between the MCA and the 1500-2000 period, are more likely to have been caused by either external forcing or by internal climate variability not well sampled during the latter half of the Twentieth Century. Finally, the results demonstrate the LIM is a viable tool for determining whether paleoclimate reconstructions events should be ascribed to external forcings, "out of sample" climate mechanisms, or if they are consistent with the variability observed during the recent period.

  18. Null-point titration measurements of free magnesium in stored erythrocytes

    International Nuclear Information System (INIS)

    Bock, J.L.; Yusuf, Y.; Puntillo, E.

    1987-01-01

    Free intracellular magnesium concentration (Mg/sub i/) was measured in stored human erythrocytes, using null-point titration with ionophore A23187. For cells stored 31 P NMR spectroscopy, which showed a decrease in Mg/sub i/ with storage. However, the NMR measurements are performed with no pretreatment of the cells, while the null-point method requires an initial washing step, which alters pH/sub i/ and may also alter Mg/sub i/. The titration-measured Mg/sub i/ values are still surprisingly low for long-stored cells, considering that depletion of ATP and 2,3-DPG should release bound Mg. Using the titration-measured Mg/sub i/ values along with measurements of total Mg, ATP, and 2,3-DPG, they estimate that an additional buffer contains about 47% of total Mg in cells stored 21 days. Mg/sub i/ determinations by both 31 P NMR and null-point titration thus indicate that erythrocyte Mg is largely bound to a high-capacity, low-affinity buffer whose relative importance increases during cell storage. Discrepancies between the methods require further investigation

  19. Asymptotic symmetries of Rindler space at the horizon and null infinity

    International Nuclear Information System (INIS)

    Chung, Hyeyoun

    2010-01-01

    We investigate the asymptotic symmetries of Rindler space at null infinity and at the event horizon using both systematic and ad hoc methods. We find that the approaches that yield infinite-dimensional asymptotic symmetry algebras in the case of anti-de Sitter and flat spaces only give a finite-dimensional algebra for Rindler space at null infinity. We calculate the charges corresponding to these symmetries and confirm that they are finite, conserved, and integrable, and that the algebra of charges gives a representation of the asymptotic symmetry algebra. We also use relaxed boundary conditions to find infinite-dimensional asymptotic symmetry algebras for Rindler space at null infinity and at the event horizon. We compute the charges corresponding to these symmetries and confirm that they are finite and integrable. We also determine sufficient conditions for the charges to be conserved on-shell, and for the charge algebra to give a representation of the asymptotic symmetry algebra. In all cases, we find that the central extension of the charge algebra is trivial.

  20. Percentiles of the null distribution of 2 maximum lod score tests.

    Science.gov (United States)

    Ulgen, Ayse; Yoo, Yun Joo; Gordon, Derek; Finch, Stephen J; Mendell, Nancy R

    2004-01-01

    We here consider the null distribution of the maximum lod score (LOD-M) obtained upon maximizing over transmission model parameters (penetrance values, dominance, and allele frequency) as well as the recombination fraction. Also considered is the lod score maximized over a fixed choice of genetic model parameters and recombination-fraction values set prior to the analysis (MMLS) as proposed by Hodge et al. The objective is to fit parametric distributions to MMLS and LOD-M. Our results are based on 3,600 simulations of samples of n = 100 nuclear families ascertained for having one affected member and at least one other sibling available for linkage analysis. Each null distribution is approximately a mixture p(2)(0) + (1 - p)(2)(v). The values of MMLS appear to fit the mixture 0.20(2)(0) + 0.80chi(2)(1.6). The mixture distribution 0.13(2)(0) + 0.87chi(2)(2.8). appears to describe the null distribution of LOD-M. From these results we derive a simple method for obtaining critical values of LOD-M and MMLS. Copyright 2004 S. Karger AG, Basel

  1. Genotyping in the Brazilian Criollo Horse Stud Book: resources and perspectives.

    Science.gov (United States)

    Costa, M A P; Bressel, R M C; Almeida, D B; Oliveira, P A; Bassini, L N; Moreira, C G A; Manzke, V H B; Siewerdt, F; Moreira, H L M

    2010-08-24

    The goal of this research was to evaluate the ability of the genotyping information available in the Brazilian Criollo Horse Stud Book to describe the genetic variability of the breed and the exclusion probability determined in comparative tests. Altogether, two softwares were used in the analyses of the available genotypes: Cervus 3.0.3 and Genepop 4.0. Eight microsatellite markers totaled 109 alleles, with an average of 13.6 +/- 0.6 alleles per locus. Large differences between expected and observed heterozygosity were ubiquitous (0.821 +/- 0.07 and 0.470 +/- 0.17, respectively). Although the estimated null allele frequency caused initial concern (0.284 +/- 0.199), it is likely that it was a reflection of the inbreeding coefficients found (0.432 +/- 0.184). All loci showed significant deviation from Hardy-Weinberg equilibrium, with heterozygote deficit (P < 0.0001) and genotypic linkage disequilibrium with at least one marker. The high polymorphic information content (0.798 +/- 0.088) could not warrant exclusion power for three loci (HMS7, HMS6 and HTG4) above 50% (0.491 +/- 0.158). However, combined exclusion probability reached 99.61%, a level close to ideal. The results demonstrate the excellent performance of the markers assessed in describing the genetic status of the breed and suggest the considerable ability to establish parentage.

  2. Applications of blood group genotyping

    Directory of Open Access Journals (Sweden)

    Mariza A. Mota

    2006-03-01

    Full Text Available Introduction: The determination of blood group polymorphism atthe genomic level facilitates the resolution of clinical problemsthat cannot be addressed by hemagglutination. They are useful to(a determine antigen types for which currently available antibodiesare weakly reactive; (b type patients who have been recentlytransfused; (c identify fetuses at risk for hemolytic disease of thenewborn; and (d to increase the reliability of repositories of antigennegative RBCs for transfusion. Objectives: This review assessedthe current applications of blood group genotyping in transfusionmedicine and hemolytic disease of the newborn. Search strategy:Blood group genotyping studies and reviews were searched ingeneral database (MEDLINE and references were reviewed.Selection criteria: All published data and reviews were eligible forinclusion provided they reported results for molecular basis ofblood group antigens, DNA analysis for blood group polymorphisms,determination of fetal group status and applications of blood groupgenotyping in blood transfusion. Data collection: All data werecollected based on studies and reviews of blood grouppolymorphisms and their clinical applications.

  3. Grain yield stability of early maize genotypes

    Directory of Open Access Journals (Sweden)

    Chitra Bahadur Kunwar

    2016-12-01

    Full Text Available The objective of this study was to estimate grain yield stability of early maize genotypes. Five early maize genotypes namely Pool-17, Arun1EV, Arun-4, Arun-2 and Farmer’s variety were evaluated using Randomized Complete Block Design along with three replications at four different locations namely Rampur, Rajahar, Pakhribas and Kabre districts of Nepal during summer seasons of three consecutive years from 2010 to 2012 under farmer’s fields. Genotype and genotype × environment (GGE biplot was used to identify superior genotype for grain yield and stability pattern. The genotypes Arun-1 EV and Arun-4 were better adapted for Kabre and Pakhribas where as pool-17 for Rajahar environments. The overall findings showed that Arun-1EV was more stable followed by Arun-2 therefore these two varieties can be recommended to farmers for cultivation in both environments.

  4. Lack of consensus in social systems

    Science.gov (United States)

    Benczik, I. J.; Benczik, S. Z.; Schmittmann, B.; Zia, R. K. P.

    2008-05-01

    We propose an exactly solvable model for the dynamics of voters in a two-party system. The opinion formation process is modeled on a random network of agents. The dynamical nature of interpersonal relations is also reflected in the model, as the connections in the network evolve with the dynamics of the voters. In the infinite time limit, an exact solution predicts the emergence of consensus, for arbitrary initial conditions. However, before consensus is reached, two different metastable states can persist for exponentially long times. One state reflects a perfect balancing of opinions, the other reflects a completely static situation. An estimate of the associated lifetimes suggests that lack of consensus is typical for large systems.

  5. Heterogeneous recombination among Hepatitis B virus genotypes.

    Science.gov (United States)

    Castelhano, Nadine; Araujo, Natalia M; Arenas, Miguel

    2017-10-01

    The rapid evolution of Hepatitis B virus (HBV) through both evolutionary forces, mutation and recombination, allows this virus to generate a large variety of adapted variants at both intra and inter-host levels. It can, for instance, generate drug resistance or the diverse viral genotypes that currently exist in the HBV epidemics. Concerning the latter, it is known that recombination played a major role in the emergence and genetic diversification of novel genotypes. In this regard, the quantification of viral recombination in each genotype can provide relevant information to devise expectations about the evolutionary trends of the epidemic. Here we measured the amount of this evolutionary force by estimating global and local recombination rates in >4700 HBV complete genome sequences corresponding to nine (A to I) HBV genotypes. Counterintuitively, we found that genotype E presents extremely high levels of recombination, followed by genotypes B and C. On the other hand, genotype G presents the lowest level, where recombination is almost negligible. We discuss these findings in the light of known characteristics of these genotypes. Additionally, we present a phylogenetic network to depict the evolutionary history of the studied HBV genotypes. This network clearly classified all genotypes into specific groups and indicated that diverse pairs of genotypes are derived from a common ancestor (i.e., C-I, D-E and, F-H) although still the origin of this virus presented large uncertainty. Altogether we conclude that the amount of observed recombination is heterogeneous among HBV genotypes and that this heterogeneity can influence on the future expansion of the epidemic. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Selection of common bean genotypes for the Cerrado/Pantanal ecotone via mixed models and multivariate analysis.

    Science.gov (United States)

    Corrêa, A M; Pereira, M I S; de Abreu, H K A; Sharon, T; de Melo, C L P; Ito, M A; Teodoro, P E; Bhering, L L

    2016-10-17

    The common bean, Phaseolus vulgaris, is predominantly grown on small farms and lacks accurate genotype recommendations for specific micro-regions in Brazil. This contributes to a low national average yield. The aim of this study was to use the methods of the harmonic mean of the relative performance of genetic values (HMRPGV) and the centroid, for selecting common bean genotypes with high yield, adaptability, and stability for the Cerrado/Pantanal ecotone region in Brazil. We evaluated 11 common bean genotypes in three trials carried out in the dry season in Aquidauana in 2013, 2014, and 2015. A likelihood ratio test detected a significant interaction between genotype x year, contributing 54% to the total phenotypic variation in grain yield. The three genotypes selected by the joint analysis of genotypic values in all years (Carioca Precoce, BRS Notável, and CNFC 15875) were the same as those recommended by the HMRPGV method. Using the centroid method, genotypes BRS Notável and CNFC 15875 were considered ideal genotypes based on their high stability to unfavorable environments and high responsiveness to environmental improvement. We identified a high association between the methods of adaptability and stability used in this study. However, the use of centroid method provided a more accurate and precise recommendation of the behavior of the evaluated genotypes.

  7. Multi-Segment Radius Measurement Using an Absolute Distance Meter Through a Null Assembly

    Science.gov (United States)

    Merle, Cormic; Wick, Eric; Hayden, Joseph

    2011-01-01

    This system was one of the test methods considered for measuring the radius of curvature of one or more of the 18 segmented mirrors that form the 6.5 m diameter primary mirror (PM) of the James Webb Space Telescope (JWST). The assembled telescope will be tested at cryogenic temperatures in a 17-m diameter by 27-m high vacuum chamber at the Johnson Space Center. This system uses a Leica Absolute Distance Meter (ADM), at a wavelength of 780 nm, combined with beam-steering and beam-shaping optics to make a differential distance measurement between a ring mirror on the reflective null assembly and individual PM segments. The ADM is located inside the same Pressure-Tight Enclosure (PTE) that houses the test interferometer. The PTE maintains the ADM and interferometer at ambient temperature and pressure so that they are not directly exposed to the telescope s harsh cryogenic and vacuum environment. This system takes advantage of the existing achromatic objective and reflective null assembly used by the test interferometer to direct four ADM beamlets to four PM segments through an optical path that is coincident with the interferometer beam. A mask, positioned on a linear slide, contains an array of 1.25 mm diameter circular subapertures that map to each of the 18 PM segments as well as six positions around the ring mirror. A down-collimated 4 mm ADM beam simultaneously covers 4 adjacent PM segment beamlets and one ring mirror beamlet. The radius, or spacing, of all 18 segments can be measured with the addition of two orthogonally-oriented scanning pentaprisms used to steer the ADM beam to any one of six different sub-aperture configurations at the plane of the ring mirror. The interferometer beam, at a wavelength of 687 nm, and the ADM beamlets, at a wavelength of 780 nm, pass through the objective and null so that the rays are normally incident on the parabolic PM surface. After reflecting off the PM, both the ADM and interferometer beams return to their respective

  8. Hepatitis C virus genotypes in Myanmar.

    Science.gov (United States)

    Win, Nan Nwe; Kanda, Tatsuo; Nakamoto, Shingo; Yokosuka, Osamu; Shirasawa, Hiroshi

    2016-07-21

    Myanmar is adjacent to India, Bangladesh, Thailand, Laos and China. In Myanmar, the prevalence of hepatitis C virus (HCV) infection is 2%, and HCV infection accounts for 25% of hepatocellular carcinoma. In this study, we reviewed the prevalence of HCV genotypes in Myanmar. HCV genotypes 1, 3 and 6 were observed in volunteer blood donors in and around the Myanmar city of Yangon. Although there are several reports of HCV genotype 6 and its variants in Myanmar, the distribution of the HCV genotypes has not been well documented in areas other than Yangon. Previous studies showed that treatment with peginterferon and a weight-based dose of ribavirin for 24 or 48 wk could lead to an 80%-100% sustained virological response (SVR) rates in Myanmar. Current interferon-free treatments could lead to higher SVR rates (90%-95%) in patients infected with almost all HCV genotypes other than HCV genotype 3. In an era of heavy reliance on direct-acting antivirals against HCV, there is an increasing need to measure HCV genotypes, and this need will also increase specifically in Myanmar. Current available information of HCV genotypes were mostly from Yangon and other countries than Myanmar. The prevalence of HCV genotypes in Myanmar should be determined.

  9. Hepatitis C Virus: Virology and Genotypes

    KAUST Repository

    Abdelaziz, Ahmed

    2017-12-01

    Hepatitis C virus (HCV) is a major causative agent of chronic liver disease worldwide. HCV is characterized by genetic heterogeneity, with at least six genotypes identified. The geographic distribution of genotypes has shown variations in different parts of the world over the past decade because of variations in population structure, immigration, and routes of transmission. Genotype differences are of epidemiologic interest and help the study of viral transmission dynamics to trace the source of HCV infection in a given population. HCV genotypes are also of considerable clinical importance because they affect response to antiviral therapy and represent a challenging obstacle for vaccine development.

  10. Wild-type offspring of heterozygous prolactin receptor-null female mice have maladaptive β-cell responses during pregnancy.

    Science.gov (United States)

    Huang, Carol

    2013-03-01

    Abstract  β-Cell mass increases during pregnancy in adaptation to the insulin resistance of pregnancy. This increase is accompanied by an increase in β-cell proliferation, a process that requires intact prolactin receptor (Prlr) signalling. Previously, it was found that during pregnancy, heterozygous prolactin receptor-null (Prlr(+/-)) mice had lower number of β-cells, lower serum insulin and higher blood glucose levels than wild-type (Prlr(+/+)) mice. An unexpected observation was that the glucose homeostasis of the experimental mouse depends on the genotype of her mother, such that within the Prlr(+/+) group, the Prlr(+/+) offspring derived from Prlr(+/+) mothers (Prlr(+/+(+/+))) had higher β-cell mass and lower blood glucose than those derived from Prlr(+/-) mothers (Prlr(+/+(+/-))). Pathways that are known to regulate β-cell proliferation during pregnancy include insulin receptor substrate-2, Akt, menin, the serotonin synthetic enzyme tryptophan hydroxylase-1, Forkhead box M1 and Forkhead box D3. The aim of the present study was to determine whether dysregulation in these signalling molecules in the islets could explain the maternal effect on the phenotype of the offspring. It was found that the pregnancy-induced increases in insulin receptor substrate-2 and Akt expression in the islets were attenuated in the Prlr(+/+(+/-)) mice in comparison to the Prlr(+/+(+/+)) mice. The expression of Forkhead box D3, which plays a permissive role for β-cell proliferation during pregnancy, was also lower in the Prlr(+/+(+/-)) mice. In contrast, the pregnancy-induced increases in phospho-Jak2, tryptophan hydroxylase-1 and FoxM1, as well as the pregnancy-associated reduction in menin expression, were comparable between the two groups. There was also no difference in expression levels of genes that regulate insulin synthesis and secretion (i.e. glucose transporter 2, glucokinase and pancreatic and duodenal homeobox-1) between these two groups. Taken together, these

  11. Molecular Epidemiology Study in Xuanwei: the Relationship among
Coal Type, Genotype and Lung Cancer Risk

    Directory of Open Access Journals (Sweden)

    Jihua LI

    2015-01-01

    Full Text Available Background and objective It has been proven that the lung cancer mortality rate in Xuanwei County, China was among the highest in the country and has been associated with exposure to indoor smoky coal emissions that contain high levels of polycyclic aromatic hydrocarbons. This risk may be modified by variation in genetic polymorphisms and coal subtypes. Our objective was to use molecular epidemiological techniques to investigate the relationship among genetic polymorphisms, coal subtype and lung cancer risk in Xuanwei County. Methods On the basis of two population-based case-control studies in residents of Xuanwei County, China, questionnaires covering demographic information, smoking history, family and personal medical history, and information on other variables were administered and buccal cells and sputum samples were collected separately from each subject enrolled to extract DNA. GST superfamily, AKR1C3 superfamily, OGG1 superfamily and other genotype were scanned by useing PCR method. ORs and 95%CIs were used to estimate the association between genotypes, coal subtypes and lung cancer risk factors by conditional Logistic regression using Statistical Analysis Software. Results Compared with subjects who using smokeless coal or wood, smoky coal use was statistically significantly associated with lung cancer risk (OR=7.7, 95%CI: 4.5-13.3. There was marked heterogeneity in risk estimates for specific subtypes of smoky coal. Estimates were highest for coal from the Laibin (OR=24.8, Longtan (OR=11.6 and Baoshan (OR=6.0 coal types, and lower for coal from other types; the risk within the same subtype of coal in male and female were similar. The GSTM1-null genotype, the AKR1C3 (Ex1-70C>G, OGG1 (Ex6-315C>G genotypes were closely associated with increased risk of lung cancer in Xuanwei County, and their odds ratios (95%CI were 2.3 (1.3-4.2, 1.8 (1.0-3.5 and 1.9 (1.1-3.3, respectively. Compared to subjects who with GSTM1-positive and used less than

  12. Genotypic Diversity of Escherichia coli in the Water and Soil of Tropical Watersheds in Hawaii ▿

    Science.gov (United States)

    Goto, Dustin K.; Yan, Tao

    2011-01-01

    High levels of Escherichia coli were frequently detected in tropical soils in Hawaii, which present important environmental sources of E. coli to water bodies. This study systematically examined E. coli isolates from water and soil of several watersheds in Hawaii and observed high overall genotypic diversity (35.5% unique genotypes). In the Manoa watershed, fewer than 9.3% of the observed E. coli genotypes in water and 6.6% in soil were shared between different sampling sites, suggesting the lack of dominant fecal sources in the watershed. High temporal variability of E. coli genotypes in soil was also observed, which suggests a dynamic E. coli population corresponding with the frequently observed high concentrations in tropical soils. When E. coli genotypes detected from the same sampling events were compared, limited sharing between the soil and water samples was observed in the majority of comparisons (73.5%). However, several comparisons reported up to 33.3% overlap of E. coli genotypes between soil and water, illustrating the potential for soil-water interactions under favorable environmental conditions. In addition, genotype accumulation curves for E. coli from water and soil indicated that the sampling efforts in the Manoa watershed could not exhaust the overall genotypic diversity. Comparisons of E. coli genotypes from other watersheds on Oahu, Hawaii, identified no apparent grouping according to sampling locations. The results of the present study demonstrate the complexity of using E. coli as a fecal indicator bacterium in tropical watersheds and highlight the need to differentiate environmental sources of E. coli from fecal sources in water quality monitoring. PMID:21515724

  13. The Fourier-Kelvin Stellar Interferometer (FKSI) Nulling Testbed II: Closed-loop Path Length Metrology And Control Subsystem

    Science.gov (United States)

    Frey, B. J.; Barry, R. K.; Danchi, W. C.; Hyde, T. T.; Lee, K. Y.; Martino, A. J.; Zuray, M. S.

    2006-01-01

    The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for an imaging and nulling interferometer in the near to mid-infrared spectral region (3-8 microns), and will be a scientific and technological pathfinder for upcoming missions including TPF-I/DARWIN, SPECS, and SPIRIT. At NASA's Goddard Space Flight Center, we have constructed a symmetric Mach-Zehnder nulling testbed to demonstrate techniques and algorithms that can be used to establish and maintain the 10(exp 4) null depth that will be required for such a mission. Among the challenges inherent in such a system is the ability to acquire and track the null fringe to the desired depth for timescales on the order of hours in a laboratory environment. In addition, it is desirable to achieve this stability without using conventional dithering techniques. We describe recent testbed metrology and control system developments necessary to achieve these goals and present our preliminary results.

  14. Nickel reactivity and filaggrin null mutations--evaluation of the filaggrin bypass theory in a general population

    DEFF Research Database (Denmark)

    Ross-Hansen, Katrine; Menné, Torkil; Johansen, Jeanne D

    2011-01-01

    It was recently shown that filaggrin null mutation carrier status was associated with nickel allergy and self-reported intolerance to costume jewellery. Because of the biochemical characteristics of filaggrin, it may show nickel barrier properties in the stratum corneum....

  15. Entry into Midgut Epithelial Cells is a Key Step in the Selection of Genotypes in a Nucleopolyhedrovirus

    Institute of Scientific and Technical Information of China (English)

    Gabriel Clavijo; Trevor Williams; Delia Mu(n)oz; Miguel L(o)pez-Ferber; Primitivo Caballero

    2009-01-01

    An isolate of the Spodoptera frugiperda multiple nucleopolyhedrovirus comprises a stable proportion of deletion genotypes (e.g., SfNIC-C), that lack pif1 and pif2 rendering them noninfectious per os, and that survive by complementation with a complete genotype (SfNIC-B) in coinfected cells. To determine whether selection for particular ratios of complete and deletion genotypes occurs mainly during the establishment of the primary infection in insect midgut cells or during subsequent systemic infection, we examined genotype frequencies in insects that fed on OBs comprising different co-occluded mixtures of genotypes. Dramatic changes in genotype frequencies were observed between the OB inoculum and budded virus (BV) samples taken from larvae inoculated with OBs comprising 10% SfNIC-B + 90% SfNIC-C indicating that a marked reduction of SfNIC-C genotype had occurred in the insect midgut due to the immediate elimination of all OBs that originated from cells that had been infected only by SfNIC-C. In contrast, immediate changes were not observed in OBs comprising mixtures of 50% SfNIC-B + 50% SfNIC-C or those comprising 10% SfNIC-B + 90% SfNIC-C as most of the OBs in these mixtures originated from cells that had been infected by both genotypes. Subsequent changes in genotypic frequencies during five days of systemic infection were fairly small in magnitude for all genotypic mixtures. We conclude that the prevalence of defective genotypes in the SfNIC population is likely determined by a balance between host selection against OBs produced in cells infected by SfNIC-C alone and within-host selection for fast-replicating deletion genotypes. The strength of intra-host selection is likely modulated by changes in MOI during the infection period.

  16. Evaluation of the Abbott Real Time HCV genotype II assay for Hepatitis C virus genotyping.

    Science.gov (United States)

    Sariguzel, Fatma Mutlu; Berk, Elife; Gokahmetoglu, Selma; Ercal, Baris Derya; Celik, Ilhami

    2015-01-01

    The determination of HCV genotypes and subtypes is very important for the selection of antiviral therapy and epidemiological studies. The aim of this study was to evaluate the performance of Abbott Real Time HCV Genotype II assay in HCV genotyping of HCV infected patients in Kayseri, Turkey. One hundred patients with chronic hepatitis C admitted to our hospital were evaluated between June 2012 and December 2012, HCV RNA levels were determined by the COBAS® AmpliPrep/COBAS® TaqMan® 48 HCV test. HCV genotyping was investigated by the Abbott Real Time HCV Genotype II assay. With the exception of genotype 1, subtypes of HCV genotypes could not be determined by Abbott assay. Sequencing analysis was used as the reference method. Genotypes 1, 2, 3 and 4 were observed in 70, 4, 2 and 24 of the 100 patients, respectively, by two methods. The concordance between the two systems to determine HCV major genotypes was 100%. Of 70 patients with genotype 1, 66 showed infection with subtype 1b and 4 with subtype 1a by Abbott Real Time HCV Genotype II assay. Using sequence analysis, 61 showed infection with subtype 1b and 9 with subtype 1a. In determining of HCV genotype 1 subtypes, the difference between the two methods was not statistically significant (P>0.05). HCV genotype 4 and 3 samples were found to be subtype 4d and 3a, respectively, by sequence analysis. There were four patients with genotype 2. Sequence analysis revealed that two of these patients had type 2a and the other two had type 2b. The Abbott Real Time HCV Genotype II assay yielded results consistent with sequence analysis. However, further optimization of the Abbott Real Time HCV Genotype II assay for subtype identification of HCV is required.

  17. Abnormal nociception and opiate sensitivity of STOP null mice exhibiting elevated levels of the endogenous alkaloid morphine

    Directory of Open Access Journals (Sweden)

    Aunis Dominique

    2010-12-01

    Full Text Available Abstract Background- Mice deficient for the stable tubule only peptide (STOP display altered dopaminergic neurotransmission associated with severe behavioural defects including disorganized locomotor activity. Endogenous morphine, which is present in nervous tissues and synthesized from dopamine, may contribute to these behavioral alterations since it is thought to play a role in normal and pathological neurotransmission. Results- In this study, we showed that STOP null brain structures, including cortex, hippocampus, cerebellum and spinal cord, contain high endogenous morphine amounts. The presence of elevated levels of morphine was associated with the presence of a higher density of mu opioid receptor with a higher affinity for morphine in STOP null brains. Interestingly, STOP null mice exhibited significantly lower nociceptive thresholds to thermal and mechanical stimulations. They also had abnormal behavioural responses to the administration of exogenous morphine and naloxone. Low dose of morphine (1 mg/kg, i.p. produced a significant mechanical antinociception in STOP null mice whereas it has no effect on wild-type mice. High concentration of naloxone (1 mg/kg was pronociceptive for both mice strain, a lower concentration (0.1 mg/kg was found to increase the mean mechanical nociceptive threshold only in the case of STOP null mice. Conclusions- Together, our data show that STOP null mice displayed elevated levels of endogenous morphine, as well as an increase of morphine receptor affinity and density in brain. This was correlated with hypernociception and impaired pharmacological sensitivity to mu opioid receptor ligands.

  18. Expression Profiling of Differentiating Emerin-Null Myogenic Progenitor Identifies Molecular Pathways Implicated in Their Impaired Differentiation

    Directory of Open Access Journals (Sweden)

    Ashvin Iyer

    2017-10-01

    Full Text Available Mutations in the gene encoding emerin cause Emery-Dreifuss muscular dystrophy (EDMD, a disorder causing progressive skeletal muscle wasting, irregular heart rhythms and contractures of major tendons. RNA sequencing was performed on differentiating wildtype and emerin-null myogenic progenitors to identify molecular pathways implicated in EDMD, 340 genes were uniquely differentially expressed during the transition from day 0 to day 1 in wildtype cells. 1605 genes were uniquely expressed in emerin-null cells; 1706 genes were shared among both wildtype and emerin-null cells. One thousand and forty-seven transcripts showed differential expression during the transition from day 1 to day 2. Four hundred and thirty-one transcripts showed altered expression in both wildtype and emerin-null cells. Two hundred and ninety-five transcripts were differentially expressed only in emerin-null cells and 321 transcripts were differentially expressed only in wildtype cells. DAVID, STRING and Ingenuity Pathway Analysis identified pathways implicated in impaired emerin-null differentiation, including cell signaling, cell cycle checkpoints, integrin signaling, YAP/TAZ signaling, stem cell differentiation, and multiple muscle development and myogenic differentiation pathways. Functional enrichment analysis showed biological functions associated with the growth of muscle tissue and myogenesis of skeletal muscle were inhibited. The large number of differentially expressed transcripts upon differentiation induction suggests emerin functions during transcriptional reprograming of progenitors to committed myoblasts.

  19. Connective tissue growth factor/CCN2-null mouse embryonic fibroblasts retain intact transforming growth factor-β responsiveness

    International Nuclear Information System (INIS)

    Mori, Yasuji; Hinchcliff, Monique; Wu, Minghua; Warner-Blankenship, Matthew; Lyons, Karen M.; Varga, John

    2008-01-01

    Background: The matricellular protein connective tissue growth factor (CCN2) has been implicated in pathological fibrosis, but its physiologic role remains elusive. In vitro, transforming growth factor-β (TGF-β) induces CCN2 expression in mesenchymal cells. Because CCN2 can enhance profibrotic responses elicited by TGF-β, it has been proposed that CCN2 functions as an essential downstream signaling mediator for TGF-β. To explore this notion, we characterized TGF-β-induced activation of fibroblasts from CCN2-null (CCN2 -/- ) mouse embryos. Methods: The regulation of CCN2 expression was examined in vivo in a model of fibrosis induced by bleomycin. Cellular TGF-β signal transduction and regulation of collagen gene expression were examined in CCN2 -/- MEFs by immunohistochemistry, Northern, Western and RT-PCR analysis, immunocytochemistry and transient transfection assays. Results: Bleomycin-induced skin fibrosis in the mouse was associated with substantial CCN2 up-regulation in lesional fibroblasts. Whereas in vitro proliferation rate of CCN2 -/- MEFs was markedly reduced compared to wild type MEFs, TGF-β-induced activation of the Smad pathways, including Smad2 phosphorylation, Smad2/3 and Smad4 nuclear accumulation and Smad-dependent transcriptional responses, were unaffected by loss of CCN2. The stimulation of COL1A2 and fibronectin mRNA expression and promoter activity, and of corresponding protein levels, showed comparable time and dose-response in wild type and CCN2 -/- MEFs, whereas stimulation of alpha smooth muscle actin and myofibroblast transdifferentiation showed subtle impairment in MEFs lacking CCN2. Conclusion: Whereas endogenous CCN2 plays a role in regulation of proliferation and TGF-β-induced myofibroblast transdifferentiation, it appears to be dispensable for Smad-dependent stimulation of collagen and extracellular matrix synthesis in murine embryonic fibroblasts

  20. Lack of RNase L attenuates macrophage functions.

    Directory of Open Access Journals (Sweden)

    Xin Yi

    Full Text Available Macrophages are one of the major cell types in innate immunity against microbial infection. It is believed that the expression of proinflammatory genes such as tumor necrosis factor-α (TNF-α, interleukin (IL-1β, IL-6, and cyclooxygenase-2 (Cox-2 by macrophages is also crucial for activation of both innate and adaptive immunities. RNase L is an interferon (IFN inducible enzyme which is highly expressed in macrophages. It has been demonstrated that RNase L regulates the expression of certain inflammatory genes. However, its role in macrophage function is largely unknown.Bone marrow-derived macrophages (BMMs were generated from RNase L(+/+and (-/- mice. The migration of BMMs was analyzed by using Transwell migration assays. Endocytosis and phagocytosis of macrophages were assessed by using fluorescein isothiocyanate (FITC-Dextran 40,000 and FITC-E. coli bacteria, respectively. The expression of inflammatory genes was determined by Western Blot and ELISA. The promoter activity of Cox-2 was measured by luciferase reporter assays.Lack of RNase L significantly decreased the migration of BMMs induced by M-CSF, but at a less extent by GM-CSF and chemokine C-C motif ligand-2 (CCL2. Interestingly, RNase L deficient BMMs showed a significant reduction of endocytic activity to FITC-Dextran 40,000, but no any obvious effect on their phagocytic activity to FITC-bacteria under the same condition. RNase L impacts the expression of certain genes related to cell migration and inflammation such as transforming growth factor (TGF-β, IL-1β, IL-10, CCL2 and Cox-2. Furthermore, the functional analysis of the Cox-2 promoter revealed that RNase L regulated the expression of Cox-2 in macrophages at its transcriptional level. Taken together, our findings provide direct evidence showing that RNase L contributes to innate immunity through regulating macrophage functions.

  1. Genotyping isolates of the entomopathogenic fungus Beauveria ...

    African Journals Online (AJOL)

    Multi-locus denaturing gradient gel electrophoresis (DGGE) analysis was developed to investigate the genotypes of Beauveria bassiana sensu lato. ... These results demonstrated that multi-locus DGGE is a potentially useful molecular marker for genotyping, identifying and tracking the fates of experimentally released ...

  2. Genetic relationship among Musa genotypes revealed by ...

    African Journals Online (AJOL)

    enoh

    2012-03-29

    Mar 29, 2012 ... A banana germplasm was established containing 44 Musa genotypes collected from various locations in Malaysia. To detect their genetic variation and to rule out duplicates among cultivar, microsatellite markers were used in their analysis. The microsatellite profiles of 44 Musa genotypes of various origins.

  3. Is the use of IL28B genotype justified in the era of interferon-free treatments for hepatitis C?

    Science.gov (United States)

    Kanda, Tatsuo; Nakamoto, Shingo; Yokosuka, Osamu

    2015-01-01

    In 2009, several groups reported that interleukin-28B (IL28B) genotypes are associated with the response to peginterferon plus ribavirin therapy for chronic hepatitis C virus (HCV) infection in a genome-wide association study, although the mechanism of this association is not yet well understood. However, in recent years, tremendous progress has been made in the treatment of HCV infection. In Japan, some patients infected with HCV have the IL28B major genotype, which may indicate a favorable response to interferon-including regimens; however, certain patients within this group are also interferon-intolerant or ineligible. In Japan, interferon-free 24-wk regimens of asunaprevir and daclatasvir are now available for HCV genotype 1b-infected patients who are interferon-intolerant or ineligible or previous treatment null-responders. The treatment response to interferon-free regimens appears better, regardless of IL28B genotype. Maybe other interferon-free regimens will widely be available soon. In conclusion, although some HCV-infected individuals have IL28B favorable alleles, importance of IL28B will be reduced with availability of oral interferon free regimen. PMID:26279979

  4. CD28-, CD45RA(null/dim) and natural killer-like CD8+ T cells are increased in peripheral blood of women with low-grade cervical lesions.

    Science.gov (United States)

    Pita-Lopez, Maria Luisa; Ortiz-Lazareno, Pablo Cesar; Navarro-Meza, Monica; Santoyo-Telles, Felipe; Peralta-Zaragoza, Oscar

    2014-01-01

    In response to antigen naive CD8+, T cells differentiate into effector cells, which express Natural killer (NK) receptors, lose CD28 expression, and die by apoptosis. However, in smaller quantities, the cells are retained for subsequent exposure to the same antigen. Knowledge is limited regarding whether the percentages of CD28-, Effector memory (EMRA(null/dim)), and the CD16+/CD56 + CD8+ T cells of women with low-grade cervical lesions are altered at a systemic level. We enrolled in this study women controls and women with Human papilloma virus infection (HPV-I) without associated cellular neoplastic changes and with Cervical Intraepithelial Neoplastic-I (CIN-I). Flow cytometry (FC) was performed for measurement of CD28-, memory subset, and NK-like CD8 + T cells, and IL-17, IFN-gamma, Tumor necrosis factor (TNF)-alpha, Interleukin (IL)-10, IL-6, IL-4, and IL-2. Finally, we genotyped the HPV. The CIN-I group increased the CD8 + CD28- and CD16+/56+ T cell percentage compared with that of HPV-I and controls (p levels among all groups. Increased levels of CD28-, EMRA(null/dim), and CD16+/CD56 + CD8+ T cells of peripheral blood in women with CIN-I may be associated with persistent HPV infection and could exert an influence on progression to cervical cancer.

  5. Mycobacterium tuberculosis strains of the Beijing genotype are rarely observed in tuberculosis patients in South America.

    Science.gov (United States)

    Ritacco, Viviana; López, Beatriz; Cafrune, Patricia I; Ferrazoli, Lucilaine; Suffys, Philip N; Candia, Norma; Vásquez, Lucy; Realpe, Teresa; Fernández, Jorge; Lima, Karla V; Zurita, Jeannete; Robledo, Jaime; Rossetti, Maria L; Kritski, Afranio L; Telles, Maria A; Palomino, Juan C; Heersma, Herre; van Soolingen, Dick; Kremer, Kristin; Barrera, Lucía

    2008-08-01

    The frequency of the Beijing genotype of Mycobacterium tuberculosis as a cause of tuberculosis (TB) in South America was determined by analyzing genotypes of strains isolated from patients that had been diagnosed with the disease between 1997 and 2003 in seven countries of the subcontinent. In total, 19 of the 1,202 (1.6%) TB cases carried Beijing isolates, including 11 of the 185 patients from Peru (5.9%), five of the 512 patients from Argentina (1.0%), two of the 252 Brazilian cases (0.8%), one of the 166 patients from Paraguay (0.6%) and none of the samples obtained from Chile (35), Colombia (36) and Ecuador (16). Except for two patients that were East Asian immigrants, all cases with Beijing strains were native South Americans. No association was found between carrying a strain with the Beijing genotype and having drug or multi-drug resistant disease. Our data show that presently transmission of M. tuberculosis strains of the Beijing genotype is not frequent in Latin America. In addition, the lack of association of drug resistant TB and infection with M. tuberculosis of the Beijing genotype observed presently demands efforts to define better the contribution of the virulence and lack of response to treatment to the growing spread of Beijing strains observed in other parts of the world.

  6. Mycobacterium tuberculosis strains of the Beijing genotype are rarely observed in tuberculosis patients in South America

    Directory of Open Access Journals (Sweden)

    Viviana Ritacco

    2008-08-01

    Full Text Available The frequency of the Beijing genotype of Mycobacterium tuberculosis as a cause of tuberculosis (TB in South America was determined by analyzing genotypes of strains isolated from patients that had been diagnosed with the disease between 1997 and 2003 in seven countries of the subcontinent. In total, 19 of the 1,202 (1.6% TB cases carried Beijing isolates, including 11 of the 185 patients from Peru (5.9%, five of the 512 patients from Argentina (1.0%, two of the 252 Brazilian cases (0.8%, one of the 166 patients from Paraguay (0.6% and none of the samples obtained from Chile (35, Colombia (36 and Ecuador (16. Except for two patients that were East Asian immigrants, all cases with Beijing strains were native South Americans. No association was found between carrying a strain with the Beijing genotype and having drug or multi-drug resistant disease. Our data show that presently transmission of M. tuberculosis strains of the Beijing genotype is not frequent in Latin America. In addition, the lack of association of drug resistant TB and infection with M. tuberculosis of the Beijing genotype observed presently demands efforts to define better the contribution of the virulence and lack of response to treatment to the growing spread of Beijing strains observed in other parts of the world.

  7. Numerical simulations of sheared magnetic lines at the solar null line

    Science.gov (United States)

    Kuźma, B.; Murawski, K.; Solov'ev, A.

    2015-05-01

    Aims: We perform numerical simulations of sheared magnetic lines at the magnetic null line configuration of two magnetic arcades that are settled in a gravitationally stratified and magnetically confined solar corona. Methods: We developed a general analytical model of a 2.5D solar atmospheric structure. As a particular application of this model, we adopted it for the curved magnetic field lines with an inverted Y shape that compose the null line above two magnetic arcades, which are embedded in the solar atmosphere that is specified by the realistic temperature distribution. The physical system is described by 2.5D magnetohydrodynamic equations that are numerically solved by the FLASH code. Results: The magnetic field line shearing, implemented about 200 km below the transition region, results in Alfvén and magnetoacoustic waves that are able to penetrate solar coronal regions above the magnetic null line. As a result of the coupling of these waves, partial reflection from the transition region and scattering from inhomogeneous regions the Alfvén waves experience fast attenuation on time scales comparable to their wave periods, and the physical system relaxes in time. The attenuation time grows with the large amplitude and characteristic growing time of the shearing. Conclusions: By having chosen a different magnetic flux function, the analytical model we devised can be adopted to derive equilibrium conditions for a diversity of 2.5D magnetic structures in the solar atmosphere. Movie associated to Fig. 5 is available in electronic form at http://www.aanda.org

  8. Gap junction mediated intercellular metabolite transfer in the cochlea is compromised in connexin30 null mice.

    Directory of Open Access Journals (Sweden)

    Qing Chang

    Full Text Available Connexin26 (Cx26 and connexin30 (Cx30 are two major protein subunits that co-assemble to form gap junctions (GJs in the cochlea. Mutations in either one of them are the major cause of non-syndromic prelingual deafness in humans. Because the mechanisms of cochlear pathogenesis caused by Cx mutations are unclear, we investigated effects of Cx30 null mutation on GJ-mediated ionic and metabolic coupling in the cochlea of mice. A novel flattened cochlear preparation was used to directly assess intercellular coupling in the sensory epithelium of the cochlea. Double-electrode patch clamp recordings revealed that the absence of Cx30 did not significantly change GJ conductance among the cochlear supporting cells. The preserved electrical coupling is consistent with immunolabeling data showing extensive Cx26 GJs in the cochlea of the mutant mice. In contrast, dye diffusion assays showed that the rate and extent of intercellular transfer of multiple fluorescent dyes (including a non-metabolizable D-glucose analogue, 2-NBDG among cochlear supporting cells were severely reduced in Cx30 null mice. Since the sensory epithelium in the cochlea is an avascular organ, GJ-facilitated intercellular transfer of nutrient and signaling molecules may play essential roles in cellular homeostasis. To test this possibility, NBDG was used as a tracer to study the contribution of GJs in transporting glucose into the cochlear sensory epithelium when delivered systemically. NBDG uptake in cochlear supporting cells was significantly reduced in Cx30 null mice. The decrease was also observed with GJ blockers or glucose competition, supporting the specificity of our tests. These data indicate that GJs facilitate efficient uptake of glucose in the supporting cells. This study provides the first direct experimental evidence showing that the transfer of metabolically-important molecules in cochlear supporting cells is dependent on the normal function of GJs, thereby suggesting a

  9. Null hypothesis significance tests. A mix-up of two different theories

    DEFF Research Database (Denmark)

    Schneider, Jesper Wiborg

    2015-01-01

    criticisms raised against NHST. As practiced, NHST has been characterized as a ‘null ritual’ that is overused and too often misapplied and misinterpreted. NHST is in fact a patchwork of two fundamentally different classical statistical testing models, often blended with some wishful quasi......-Bayesian interpretations. This is undoubtedly a major reason why NHST is very often misunderstood. But NHST also has intrinsic logical problems and the epistemic range of the information provided by such tests is much more limited than most researchers recognize. In this article we introduce to the scientometric community...

  10. Topology and Singularities in Cosmological Spacetimes Obeying the Null Energy Condition

    Science.gov (United States)

    Galloway, Gregory J.; Ling, Eric

    2018-06-01

    We consider globally hyperbolic spacetimes with compact Cauchy surfaces in a setting compatible with the presence of a positive cosmological constant. More specifically, for 3 + 1 dimensional spacetimes which satisfy the null energy condition and contain a future expanding compact Cauchy surface, we establish a precise connection between the topology of the Cauchy surfaces and the occurrence of past singularities. In addition to the Penrose singularity theorem, the proof makes use of some recent advances in the topology of 3-manifolds and of certain fundamental existence results for minimal surfaces.

  11. Null geodesics in black hole metrics with non-zero cosmological constant

    International Nuclear Information System (INIS)

    Stuchlik, Z.; Calvani, M.

    1990-02-01

    We study the radial motion along null geodesics in the Reissner-Nordstroem-de Sitter and Kerr-de Sitter space-times. We analyze the properties of the effective potential and we discuss circular orbits. We find that the radii of circular geodesics in the Reissner-Nordstroem-de Sitter space-time do not depend on the cosmological constant, and we explain this property using the optical reference geometry. In addition, we describe the unusual consequences of the interplay between rotation of the source and cosmological repulsion. (author). 16 refs, 8 figs

  12. Reply to "Comment on `Null weak values and the past of a quantum particle"'

    Science.gov (United States)

    Duprey, Q.; Matzkin, A.

    2018-04-01

    We discuss the preceding Comment [D. Sokolovski, preceding Comment, Phys. Rev. A 97, 046102 (2018), 10.1103/PhysRevA.97.046102] and conclude that the arguments given there against the relevance of null weak values as representing the absence of a system property are not compelling. We give an example in which the transition matrix elements that make the projector weak values vanish are the same ones that suppress detector clicks in strong measurements. Whether weak values are taken to account for the past of a quantum system or not depend on general interpretational commitments of the quantum formalism itself rather than on peculiarities of the weak measurements framework.

  13. Double null X-point operation in JET with NBI and ICRH heating

    International Nuclear Information System (INIS)

    Tubbing, B.; Bhatnagar, V.

    1989-01-01

    In this paper we report on a selection of experiments on H-modes, in 3 and 3.5MA discharges, in the double null X-point configuration. The first experiment, section 2, is an attempt to couple ICRH power to H-modes. Here we also report on a rather unique H-mode with a smaller than usual distance between plasma and limiter. The second experiment, section 3, is on H-modes in the low density, hot ion regime. (author) 5 refs., 4 figs

  14. The space-time outside a source of gravitational radiation: the axially symmetric null fluid

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, L. [Universidad Central de Venezuela, Escuela de Fisica, Facultad de Ciencias, Caracas (Venezuela, Bolivarian Republic of); Universidad de Salamanca, Instituto Universitario de Fisica Fundamental y Matematicas, Salamanca (Spain); Di Prisco, A. [Universidad Central de Venezuela, Escuela de Fisica, Facultad de Ciencias, Caracas (Venezuela, Bolivarian Republic of); Ospino, J. [Universidad de Salamanca, Departamento de Matematica Aplicada and Instituto Universitario de Fisica Fundamental y Matematicas, Salamanca (Spain)

    2016-11-15

    We carry out a study of the exterior of an axially and reflection symmetric source of gravitational radiation. The exterior of such a source is filled with a null fluid produced by the dissipative processes inherent to the emission of gravitational radiation, thereby representing a generalization of the Vaidya metric for axially and reflection symmetric space-times. The role of the vorticity, and its relationship with the presence of gravitational radiation is put in evidence. The spherically symmetric case (Vaidya) is, asymptotically, recovered within the context of the 1 + 3 formalism. (orig.)

  15. Theory of synergistic effects: Hill-type response surfaces as 'null-interaction' models for mixtures.

    Science.gov (United States)

    Schindler, Michael

    2017-08-02

    The classification of effects caused by mixtures of agents as synergistic, antagonistic or additive depends critically on the reference model of 'null interaction'. Two main approaches are currently in use, the Additive Dose (ADM) or concentration addition (CA) and the Multiplicative Survival (MSM) or independent action (IA) models. We compare several response surface models to a newly developed Hill response surface, obtained by solving a logistic partial differential equation (PDE). Assuming that a mixture of chemicals with individual Hill-type dose-response curves can be described by an n-dimensional logistic function, Hill's differential equation for pure agents is replaced by a PDE for mixtures whose solution provides Hill surfaces as 'null-interaction' models and relies neither on Bliss independence or Loewe additivity nor uses Chou's unified general theory. An n-dimensional logistic PDE decribing the Hill-type response of n-component mixtures is solved. Appropriate boundary conditions ensure the correct asymptotic behaviour. Mathematica 11 (Wolfram, Mathematica Version 11.0, 2016) is used for the mathematics and graphics presented in this article. The Hill response surface ansatz can be applied to mixtures of compounds with arbitrary Hill parameters. Restrictions which are required when deriving analytical expressions for response surfaces from other principles, are unnecessary. Many approaches based on Loewe additivity turn out be special cases of the Hill approach whose increased flexibility permits a better description of 'null-effect' responses. Missing sham-compliance of Bliss IA, known as Colby's model in agrochemistry, leads to incompatibility with the Hill surface ansatz. Examples of binary and ternary mixtures illustrate the differences between the approaches. For Hill-slopes close to one and doses below the half-maximum effect doses MSM (Colby, Bliss, Finney, Abbott) predicts synergistic effects where the Hill model indicates 'null

  16. Comments on correlation functions of large spin operators and null polygonal Wilson loops

    Energy Technology Data Exchange (ETDEWEB)

    Cardona, Carlos A., E-mail: cargicar@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), C.C. 67 - Suc. 28, 1428 Buenos Aires (Argentina); Physics Department, University of Buenos Aires, CONICET, Ciudad Universitaria, 1428 Buenos Aires (Argentina)

    2013-02-11

    We discuss the relation between correlation functions of twist-two large spin operators and expectation values of Wilson loops along light-like trajectories. After presenting some heuristic field theoretical arguments suggesting this relation, we compute the divergent part of the correlator in the limit of large 't Hooft coupling and large spins, using a semi-classical world-sheet which asymptotically looks like a GKP rotating string. We show this diverges as expected from the expectation value of a null Wilson loop, namely, as (ln{mu}{sup -2}){sup 2}, {mu} being a cut-off of the theory.

  17. The 10-D chiral null model and the relation to 4-D string solutions

    International Nuclear Information System (INIS)

    Behrndt, K.

    1994-12-01

    The chiral null model is a generalization of the fundamental string and gravitational wave background. It is an example of a conformally invariant model in all orders in α' and has unbroken supersymmetries. In a Kaluza-Klein approach we start in 10 dimensions and reduce the model down to 4 dimensions without making any restrictions. The 4-D field content is given by the metric, torsion, dilaton, a moduli field and 6 gauge fields. This model is self-dual and near the singularities asymptotically free. The relation to known IWP, Taub-NUT and rotating black hole solutions is discussed. (orig.)

  18. A critical discussion of null hypothesis significance testing and statistical power analysis within psychological research

    DEFF Research Database (Denmark)

    Jones, Allan; Sommerlund, Bo

    2007-01-01

    The uses of null hypothesis significance testing (NHST) and statistical power analysis within psychological research are critically discussed. The article looks at the problems of relying solely on NHST when dealing with small and large sample sizes. The use of power-analysis in estimating...... the potential error introduced by small and large samples is advocated. Power analysis is not recommended as a replacement to NHST but as an additional source of information about the phenomena under investigation. Moreover, the importance of conceptual analysis in relation to statistical analysis of hypothesis...

  19. Asymptotically shear-free and twist-free null geodesic congruences

    International Nuclear Information System (INIS)

    Kozameh, Carlos; Newman, Ezra T

    2007-01-01

    The Robinson-Trautman spacetime is a special case of asymptotically flat spacetimes that possess asymptotically shear-free and twist-free (surface forming) null geodesic congruences. In this paper we show that, although they are rare, a larger class of asymptotically flat spacetimes with this property does exist. In particular, we display the class of spacetimes that possess this dual property and demonstrate how these congruences can be found. In addition, we show that in each case the congruence is isolated in the sense that there are no other neighbouring congruences with this dual property

  20. High-contrast visible nulling coronagraph for segmented and arbitrary telescope apertures

    Science.gov (United States)

    Hicks, Brian A.; Lyon, Richard G.; Bolcar, Matthew R.; Clampin, Mark; Petrone, Peter

    2014-08-01

    Exoplanet coronagraphy will be driven by the telescope architectures available and thus the system designer must have available one or more suitable coronagraphic instrument choices that spans the set of telescope apertures, including filled (off-axis), obscured (e.g. with secondary mirror spiders and struts), segmented apertures, such as JWST, and interferometric apertures. In this work we present one such choice of coronagraph, known as the visible nulling coronagraph (VNC), that spans all four types of aperture and also employs differential sensing and control.

  1. Testing the null hypothesis of the nonexistence of a preseizure state

    International Nuclear Information System (INIS)

    Andrzejak, Ralph G.; Kraskov, Alexander; Mormann, Florian; Rieke, Christoph; Kreuz, Thomas; Elger, Christian E.; Lehnertz, Klaus

    2003-01-01

    A rapidly growing number of studies deals with the prediction of epileptic seizures. For this purpose, various techniques derived from linear and nonlinear time series analysis have been applied to the electroencephalogram of epilepsy patients. In none of these works, however, the performance of the seizure prediction statistics is tested against a null hypothesis, an otherwise ubiquitous concept in science. In consequence, the evaluation of the reported performance values is problematic. Here, we propose the technique of seizure time surrogates based on a Monte Carlo simulation to remedy this deficit

  2. Testing the null hypothesis of the nonexistence of a preseizure state

    Energy Technology Data Exchange (ETDEWEB)

    Andrzejak, Ralph G; Kraskov, Alexander [John-von-Neumann Institute for Computing, Forschungszentrum Juelich, 52425 Juelich (Germany); Mormann, Florian; Rieke, Christoph [Department of Epileptology, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany); Helmholtz Institut fuer Strahlen- und Kernphysik, University of Bonn, Nussallee 14-16, 53115 Bonn (Germany); Kreuz, Thomas [John-von-Neumann Institute for Computing, Forschungszentrum Juelich, 52425 Juelich (Germany); Department of Epileptology, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany); Elger, Christian E; Lehnertz, Klaus [Department of Epileptology, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn (Germany)

    2003-01-01

    A rapidly growing number of studies deals with the prediction of epileptic seizures. For this purpose, various techniques derived from linear and nonlinear time series analysis have been applied to the electroencephalogram of epilepsy patients. In none of these works, however, the performance of the seizure prediction statistics is tested against a null hypothesis, an otherwise ubiquitous concept in science. In consequence, the evaluation of the reported performance values is problematic. Here, we propose the technique of seizure time surrogates based on a Monte Carlo simulation to remedy this deficit.

  3. Comments on correlation functions of large spin operators and null polygonal Wilson loops

    International Nuclear Information System (INIS)

    Cardona, Carlos A.

    2013-01-01

    We discuss the relation between correlation functions of twist-two large spin operators and expectation values of Wilson loops along light-like trajectories. After presenting some heuristic field theoretical arguments suggesting this relation, we compute the divergent part of the correlator in the limit of large 't Hooft coupling and large spins, using a semi-classical world-sheet which asymptotically looks like a GKP rotating string. We show this diverges as expected from the expectation value of a null Wilson loop, namely, as (lnμ −2 ) 2 , μ being a cut-off of the theory.

  4. Five-dimensional null-cone structure of big bang singularity

    International Nuclear Information System (INIS)

    Lauro, S.; Schucking, E.L.

    1985-01-01

    The Friedmann model PHI of positive space curvature, vanishing pressure and cosmological constant when isometrically imbedded as a hypersurface in five-dimensional Minkowski space M 5 is globally rigid: if F(PHI) and F'(PHI) are isometric embeddings in M 5 there is a motion π of M 5 such that F'=π 0 F. The big bang singularity is the vertex of a null half-cone in M 5 . Global rigidity leads to an invariant characterization of the singularity. The structure of matter at the singularity is governed by the de Sitter group. (author)

  5. Five-dimensional null-cone structure of big bang singularity

    Energy Technology Data Exchange (ETDEWEB)

    Lauro, S.; Schucking, E.L.

    1985-04-01

    The Friedmann model PHI of positive space curvature, vanishing pressure and cosmological constant when isometrically imbedded as a hypersurface in five-dimensional Minkowski space MV is globally rigid: if F(PHI) and F'(PHI) are isometric embeddings in MV there is a motion of MV such that F'= F. The big bang singularity is the vertex of a null half-cone in MV. Global rigidity leads to an invariant characterization of the singularity. The structure of matter at the singularity is governed by the de Sitter group.

  6. Dimension shifting operators and null states in 2D conformally invariant field theories

    International Nuclear Information System (INIS)

    Gervais, J.L.

    1986-01-01

    We discuss the existence and properties of differential operators which transform covariant operators into covariant operators of different weights in two-dimensional conformally invariant field theories. We relate them to null states and the vanishing of the Kac determinant in representations of the conformal algebra, and to the existence of differential equations for Green functions of covariant operators. In this framework, we rederive the essential features of our earlier work on dual models with shifted intercept, which in euclidean space-time gives explicit solutions of the conformal bootstrap equations where all operators are marginal. (orig.)

  7. Toward fully automated genotyping: Genotyping microsatellite markers by deconvolution

    Energy Technology Data Exchange (ETDEWEB)

    Perlin, M.W.; Lancia, G.; See-Kiong, Ng [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    1995-11-01

    Dense genetic linkage maps have been constructed for the human and mouse genomes, with average densities of 2.9 cM and 0.35 cM, respectively. These genetic maps are crucial for mapping both Mendelian and complex traits and are useful in clinical genetic diagnosis. Current maps are largely comprised of abundant, easily assayed, and highly polymorphic PCR-based microsatellite markers, primarily dinucleotide (CA){sub n} repeats. One key limitation of these length polymorphisms is the PCR stutter (or slippage) artifact that introduces additional stutter bands. With two (or more) closely spaced alleles, the stutter bands overlap, and it is difficult to accurately determine the correct alleles; this stutter phenomenon has all but precluded full automation, since a human must visually inspect the allele data. We describe here novel deconvolution methods for accurate genotyping that mathematically remove PCR stutter artifact from microsatellite markers. These methods overcome the manual interpretation bottleneck and thereby enable full automation of genetic map construction and use. New functionalities, including the pooling of DNAs and the pooling of markers, are described that may greatly reduce the associated experimentation requirements. 32 refs., 5 figs., 3 tabs.

  8. Mapping the functional landscape of frequent phenylalanine hydroxylase (PAH) genotypes promotes personalised medicine in phenylketonuria.

    Science.gov (United States)

    Danecka, Marta K; Woidy, Mathias; Zschocke, Johannes; Feillet, François; Muntau, Ania C; Gersting, Søren W

    2015-03-01

    In phenylketonuria, genetic heterogeneity, frequent compound heterozygosity, and the lack of functional data for phenylalanine hydroxylase genotypes hamper reliable phenotype prediction and individualised treatment. A literature search revealed 690 different phenylalanine hydroxylase genotypes in 3066 phenylketonuria patients from Europe and the Middle East. We determined phenylalanine hydroxylase function of 30 frequent homozygous and compound heterozygous genotypes covering 55% of the study population, generated activity landscapes, and assessed the phenylalanine hydroxylase working range in the metabolic (phenylalanine) and therapeutic (tetrahydrobiopterin) space. Shared patterns in genotype-specific functional landscapes were linked to biochemical and pharmacological phenotypes, where (1) residual activity below 3.5% was associated with classical phenylketonuria unresponsive to pharmacological treatment; (2) lack of defined peak activity induced loss of response to tetrahydrobiopterin; (3) a higher cofactor need was linked to inconsistent clinical phenotypes and low rates of tetrahydrobiopterin response; and (4) residual activity above 5%, a defined peak of activity, and a normal cofactor need were associated with pharmacologically treatable mild phenotypes. In addition, we provide a web application for retrieving country-specific information on genotypes and genotype-specific phenylalanine hydroxylase function that warrants continuous extension, updates, and research on demand. The combination of genotype-specific functional analyses with biochemical, clinical, and therapeutic data of individual patients may serve as a powerful tool to enable phenotype prediction and to establish personalised medicine strategies for dietary regimens and pharmacological treatment in phenylketonuria. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  9. Comparison of Three Different Commercial Kits for the Human Papilloma Virus Genotyping.

    Science.gov (United States)

    Lim, Yong Kwan; Choi, Jee-Hye; Park, Serah; Kweon, Oh Joo; Park, Ae Ja

    2016-11-01

    High-risk type human papilloma virus (HPV) is the most important cause of cervical cancer. Recently, real-time polymerase chain reaction and reverse blot hybridization assay-based HPV DNA genotyping kits are developed. So, we compared the performances of different three HPV genotyping kits using different analytical principles and methods. Two hundred positive and 100 negative cervical swab specimens were used. DNA was extracted and all samples were tested by the MolecuTech REBA HPV-ID, Anyplex II HPV28 Detection, and HPVDNAChip. Direct sequencing was performed as a reference method for confirming high-risk HPV genotypes 16, 18, 45, 52, and 58. Although high-level agreement results were observed in negative samples, three kits showed decreased interassay agreement as screening setting in positive samples. Comparing the genotyping results, three assays showed acceptable sensitivity and specificity for the detection of HPV 16 and 18. Otherwise, various sensitivities showed in the detection of HPV 45, 52, and 58. The three assays had dissimilar performance of HPV screening capacity and exhibited moderate level of concordance in HPV genotyping. These discrepant results were unavoidable due to difference in type-specific analytical sensitivity and lack of standardization; therefore, we suggested that the efforts to standardization of HPV genotyping kits and adjusting analytical sensitivity would be important for the best clinical performance. © 2016 Wiley Periodicals, Inc.

  10. Lack of efficacy of ergocalciferol repletion

    Directory of Open Access Journals (Sweden)

    Thomas Wasser

    2012-04-01

    Full Text Available Introduction: Vitamin D has become an area of intensive scrutiny, both in medical and lay literature. However, there are limited data to suggest proper repletion regimens for those patients who have hypovitaminosis D. Consequently, various methods are used in clinical practice. The aim of this study was to assess the efficacy of various treatment strategies for hypovitaminosis D in an ambulatory internal medicine practice. Methods: A retrospective chart review between October 2005 and June 2010 of a suburban internal medicine practice was performed via query of the electronic medical record (Centricity, General Electric Healthcare, UK. Patients with a 25-hydroxyvitamin D concentration less than 32 mg/dl were identified and treated. Treatment success was defined as 25-hydroxyvitamin D concentrations greater than 32 mg/dl. Statistical analysis to assess changes in vitamin D level controlling for season, comorbidities, and demographics were used. Results: A total of 607 treatment episodes were identified, with 395 excluded due to lack of follow-up vitamin D level within 16 weeks, no treatment documented, topical treatment, doxercalciferol treatment, or non-compliance. Of the remaining patients, there were 212 treatment instances on 178 patients. Ergocalciferol 50,000 international units (IU was used most frequently (71.4% of the time.. A higher initial vitamin D level was positively associated with treatment success (adjusted odds ratio = 1.11, p=0.002. Increased doses of ergocalciferol increased the likelihood of treatment success (p=0.0011. Seasonal variation was related to posttreatment 25-hydroxyvitamin D concentration as was body mass index (BMI (p=0.003 and p=0.044. Conclusion: Pretreatment levels of 25-hydroxyvitamin D, BMI, season, and vitamin D dose are predictors of successful hypovitaminosis D treatment. Our data suggest that patients with initial 25-hydroxyvitamin D concentrations of <20 should be treated with a higher total dose of

  11. Genomic evaluations with many more genotypes

    Directory of Open Access Journals (Sweden)

    Wiggans George R

    2011-03-01

    Full Text Available Abstract Background Genomic evaluations in Holstein dairy cattle have quickly become more reliable over the last two years in many countries as more animals have been genotyped for 50,000 markers. Evaluations can also include animals genotyped with more or fewer markers using new tools such as the 777,000 or 2,900 marker chips recently introduced for cattle. Gains from more markers can be predicted using simulation, whereas strategies to use fewer markers have been compared using subsets of actual genotypes. The overall cost of selection is reduced by genotyping most animals at less than the highest density and imputing their missing genotypes using haplotypes. Algorithms to combine different densities need to be efficient because numbers of genotyped animals and markers may continue to grow quickly. Methods Genotypes for 500,000 markers were simulated for the 33,414 Holsteins that had 50,000 marker genotypes in the North American database. Another 86,465 non-genotyped ancestors were included in the pedigree file, and linkage disequilibrium was generated directly in the base population. Mixed density datasets were created by keeping 50,000 (every tenth of the markers for most animals. Missing genotypes were imputed using a combination of population haplotyping and pedigree haplotyping. Reliabilities of genomic evaluations using linear and nonlinear methods were compared. Results Differing marker sets for a large population were combined with just a few hours of computation. About 95% of paternal alleles were determined correctly, and > 95% of missing genotypes were called correctly. Reliability of breeding values was already high (84.4% with 50,000 simulated markers. The gain in reliability from increasing the number of markers to 500,000 was only 1.6%, but more than half of that gain resulted from genotyping just 1,406 young bulls at higher density. Linear genomic evaluations had reliabilities 1.5% lower than the nonlinear evaluations with 50

  12. Altered Ca2+ kinetics associated with α-actinin-3 deficiency may explain positive selection for ACTN3 null allele in human evolution.

    Directory of Open Access Journals (Sweden)

    Stewart I Head

    Full Text Available Over 1.5 billion people lack the skeletal muscle fast-twitch fibre protein α-actinin-3 due to homozygosity for a common null polymorphism (R577X in the ACTN3 gene. α-Actinin-3 deficiency is detrimental to sprint performance in elite athletes and beneficial to endurance activities. In the human genome, it is very difficult to find single-gene loss-of-function variants that bear signatures of positive selection, yet intriguingly, the ACTN3 null variant has undergone strong positive selection during recent evolution, appearing to provide a survival advantage where food resources are scarce and climate is cold. We have previously demonstrated that α-actinin-3 deficiency in the Actn3 KO mouse results in a shift in fast-twitch fibres towards oxidative metabolism, which would be more "energy efficient" in famine, and beneficial to endurance performance. Prolonged exposure to cold can also induce changes in skeletal muscle similar to those observed with endurance training, and changes in Ca2+ handling by the sarcoplasmic reticulum (SR are a key factor underlying these adaptations. On this basis, we explored the effects of α-actinin-3 deficiency on Ca2+ kinetics in single flexor digitorum brevis muscle fibres from Actn3 KO mice, using the Ca2+-sensitive dye fura-2. Compared to wild-type, fibres of Actn3 KO mice showed: (i an increased rate of decay of the twitch transient; (ii a fourfold increase in the rate of SR Ca2+ leak; (iii a threefold increase in the rate of SR Ca2+ pumping; and (iv enhanced maintenance of tetanic Ca2+ during fatigue. The SR Ca2+ pump, SERCA1, and the Ca2+-binding proteins, calsequestrin and sarcalumenin, showed markedly increased expression in muscles of KO mice. Together, these changes in Ca2+ handling in the absence of α-actinin-3 are consistent with cold acclimatisation and thermogenesis, and offer an additional explanation for the positive selection of the ACTN3 577X null allele in populations living in cold environments

  13. A European database of Fusarium graminearum and F. culmorum trichothecene genotypes

    Directory of Open Access Journals (Sweden)

    Matias ePasquali

    2016-04-01

    Full Text Available Fusarium species, particularly Fusarium graminearum and F. culmorum, are the main cause of trichothecene type B contamination in cereals. Data on the distribution of Fusarium trichothecene genotypes in cereals in Europe are scattered in time and space. Furthermore, a common core set of related variables (sampling method, host cultivar, previous crop, etc. that would allow more effective analysis of factors influencing the spatial and temporal population distribution, is lacking. Consequently, based on the available data, it is difficult to identify factors influencing chemotype distribution and spread at the European level. Here we describe the results of a collaborative integrated work which aims 1 to characterize the trichothecene genotypes of strains from three Fusarium species, collected over the period 2000-2013, and 2 to enhance the standardization of epidemiological data collection.Information on host plant, country of origin, sampling location, year of sampling and previous crop of 1147 F. graminearum, 479 F. culmorum and 3 F. cortaderiae strains obtained from 17 European countries was compiled and a map of trichothecene type B genotype distribution was plotted for each species. All information on the strains was collected in a freely accessible and updatable database (www.catalogueeu.luxmcc.lu, which will serve as a starting point for epidemiological analysis of potential spatial and temporal trichothecene genotype shifts in Europe.The analysis of the currently available European dataset showed that in F. graminearum, the predominant genotype was 15-acetyldeoxynivalenol (15-ADON (82.9%, followed by 3-acetyldeoxynivalenol (3-ADON (13.6% and nivalenol (NIV (3.5%. In F. culmorum, the prevalent genotype was 3-ADON (59.9%, while the NIV genotype accounted for the remaining 40.1%. Both geographical and temporal patterns of trichothecene genotypes distribution were identified.

  14. A near-null magnetic field affects cryptochrome-related hypocotyl growth and flowering in Arabidopsis

    Science.gov (United States)

    Xu, Chunxiao; Yin, Xiao; Lv, Yan; Wu, Changzhe; Zhang, Yuxia; Song, Tao

    2012-03-01

    The blue light receptor, cryptochrome, has been suggested to act as a magnetoreceptor based on the proposition that photochemical reactions are involved in sensing the geomagnetic field. But the effects of the geomagnetic field on cryptochrome remain unclear. Although the functions of cryptochrome have been well demonstrated for Arabidopsis, the effect of the geomagnetic field on the growth of Arabidopsis and its mechanism of action are poorly understood. We eliminated the local geomagnetic field to grow Arabidopsis in a near-null magnetic field and found that the inhibition of Arabidopsis hypocotyl growth by white light was weakened, and flowering time was delayed. The expressions of three cryptochrome-signaling-related genes, PHYB, CO and FT also changed; the transcript level of PHYB was elevated ca. 40%, and that of CO and FT was reduced ca. 40% and 50%, respectively. These data suggest that the effects of a near-null magnetic field on Arabidopsis are cryptochrome-related, which may be revealed by a modification of the active state of cryptochrome and the subsequent signaling cascade.

  15. Biological and genetic properties of the p53 null preneoplastic mammary epithelium

    Science.gov (United States)

    Medina, Daniel; Kittrell, Frances S.; Shepard, Anne; Stephens, L. Clifton; Jiang, Cheng; Lu, Junxuan; Allred, D. Craig; McCarthy, Maureen; Ullrich, Robert L.

    2002-01-01

    The absence of the tumor suppressor gene p53 confers an increased tumorigenic risk for mammary epithelial cells. In this report, we describe the biological and genetic properties of the p53 null preneoplastic mouse mammary epithelium in a p53 wild-type environment. Mammary epithelium from p53 null mice was transplanted serially into the cleared mammary fat pads of p53 wild-type BALB/c female to develop stable outgrowth lines. The outgrowth lines were transplanted for 10 generations. The outgrowths were ductal in morphology and progressed through ductal hyperplasia and ductal carcinoma in situ before invasive cancer. The preneoplastic outgrowth lines were immortal and exhibited activated telomerase activity. They are estrogen and progesterone receptor-positive, and aneuploid, and had various levels of tumorigenic potential. The biological and genetic properties of these lines are distinct from those found in most hyperplastic alveolar outgrowth lines, the form of mammary preneoplasia occurring in most traditional models of murine mammary tumorigenesis. These results indicate that the preneoplastic cell populations found in this genetically engineered model are similar in biological properties to a subset of precurser lesions found in human breast cancer and provide a unique model to identify secondary events critical for tumorigenicity and invasiveness.

  16. Nulling Data Reduction and On-Sky Performance of the Large Binocular Telescope Interferometer

    Science.gov (United States)

    Defrere, D.; Hinz, P. M.; Mennesson, B.; Hoffman, W. F.; Millan-Gabet, R.; Skemer, A. J.; Bailey, V.; Danchi, W. C.; Downy, E. C.; Durney, O.; hide

    2016-01-01

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high angular resolution and high-contrast infrared imaging (1.5-13 micrometers). In this paper, we focus on the mid-infrared (8-13 micrometers) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in 2015 March. With an interferometric baseline of 14.4 m, the LBTI nuller is specifically tuned to resolve the habitable zone of nearby main-sequence stars, where warm exozodiacal dust emission peaks. Measuring the exozodi luminosity function of nearby main-sequence stars is a key milestone to prepare for future exo-Earth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in 2015 February a calibrated null accuracy of 0.05% over a 3 hr long observing sequence on the bright nearby A3V star Beta Leo. This is equivalent to an exozodiacal disk density of 15-30 zodi for a Sun-like star located at 10 pc, depending on the adopted disk model. This result sets a new record for high-contrast mid-infrared interferometric imaging and opens a new window on the study of planetary systems.

  17. Telescopes in Near Space: Balloon Exoplanet Nulling Interferometer (BigBENI)

    Science.gov (United States)

    Lyon, Richard G.; Clampin, Mark; Petrone, Peter; Mallik, Udayan; Mauk, Robin

    2012-01-01

    A significant and often overlooked path to advancing both science and technology for direct imaging and spectroscopic characterization of exosolar planets is to fly "near space" missions, i.e. balloon borne exosolar missions. A near space balloon mission with two or more telescopes, coherently combined, is capable of achieving a subset of the mission science goals of a single large space telescope at a small fraction of the cost. Additionally such an approach advances technologies toward flight readiness for space flight. Herein we discuss the feasibility of flying two 1.2 meter telescopes, with a baseline separation of 3.6 meters, operating in visible light, on a composite boom structure coupled to a modified visible nulling coronagraph operating to achieve an inner working angle of 60 milli-arcseconds. We discuss the potential science return, atmospheric residuals at 135,000 feet, pointing control and visible nulling and evaluate the state-or-art of these technologies with regards to balloon missions.

  18. Thrombospondin 2-null mice display an altered brain foreign body response to polyvinyl alcohol sponge implants

    International Nuclear Information System (INIS)

    Tian Weiming; Kyriakides, Themis R

    2009-01-01

    Thrombospondin (TSP)-2 is a matricellular protein that participates in the processes of tissue repair and the foreign body response. In addition, TSP2 has been shown to influence synaptogenesis and recovery of the brain following stroke. In the present study we investigated the response following the implantation of polyvinyl alcohol (PVA) sponges in the brain. PVA sponges were implanted into the brain cortex of wild type and TSP2-null mice for a period of 4 and 8 weeks and the response was analyzed by histochemistry and quantitative immunohistochemistry. TSP2 expression was detected in the interstices of the sponge and co-localized with the extracellular matrix and astrocytes. PVA sponge invasion in TSP2-null mice was characterized by dense deposition of extracellular matrix and increased invasion of reactive astrocytes and macrophages/microglia. Furthermore, the angiogenic response was elevated and the detection of mouse serum albumin (MSA) in the brain cortex indicated excessive vessel leakage, suggesting that TSP2 plays a role in the repair/maintenance of the blood brain barrier. Finally, immunostaining demonstrated an increase in the levels of matrix metalloproteinase (MMP)-2 and MMP-9. Taken together, our observations support a role for TSP2 as critical determinant of the brain response to biomaterials.

  19. Optimized scheduling technique of null subcarriers for peak power control in 3GPP LTE downlink.

    Science.gov (United States)

    Cho, Soobum; Park, Sang Kyu

    2014-01-01

    Orthogonal frequency division multiple access (OFDMA) is a key multiple access technique for the long term evolution (LTE) downlink. However, high peak-to-average power ratio (PAPR) can cause the degradation of power efficiency. The well-known PAPR reduction technique, dummy sequence insertion (DSI), can be a realistic solution because of its structural simplicity. However, the large usage of subcarriers for the dummy sequences may decrease the transmitted data rate in the DSI scheme. In this paper, a novel DSI scheme is applied to the LTE system. Firstly, we obtain the null subcarriers in single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems, respectively; then, optimized dummy sequences are inserted into the obtained null subcarrier. Simulation results show that Walsh-Hadamard transform (WHT) sequence is the best for the dummy sequence and the ratio of 16 to 20 for the WHT and randomly generated sequences has the maximum PAPR reduction performance. The number of near optimal iteration is derived to prevent exhausted iterations. It is also shown that there is no bit error rate (BER) degradation with the proposed technique in LTE downlink system.

  20. The gravitational exclusion principle and null states in anti-de Sitter space

    International Nuclear Information System (INIS)

    Castro, Alejandra; Maloney, Alexander; Hartman, Thomas

    2011-01-01

    The holographic principle implies a vast reduction in the number of degrees of freedom of quantum gravity. This idea can be made precise in AdS 3 , where the the stringy or gravitational exclusion principle asserts that certain perturbative excitations are not present in the exact quantum spectrum. We show that this effect is visible directly in the bulk gravity theory: the norm of the offending linearized state is zero or negative. When the norm is negative, the theory is signalling its own breakdown as an effective field theory; this provides a perturbative bulk explanation for the stringy exclusion principle. When the norm vanishes the bulk state is null rather than physical. This implies that certain non-trivial diffeomorphisms must be regarded as gauge symmetries rather than spectrum-generating elements of the asymptotic symmetry group. This leads to subtle effects in the computation of one-loop determinants for Einstein gravity, higher spin theories and topologically massive gravity in AdS 3 . In particular, heat kernel methods do not capture the correct spectrum of a theory with null states. Communicated by S Ross

  1. Modular Hamiltonians for deformed half-spaces and the averaged null energy condition

    Science.gov (United States)

    Faulkner, Thomas; Leigh, Robert G.; Parrikar, Onkar; Wang, Huajia

    2016-09-01

    We study modular Hamiltonians corresponding to the vacuum state for deformed half-spaces in relativistic quantum field theories on {{R}}^{1,d-1} . We show that in addition to the usual boost generator, there is a contribution to the modular Hamiltonian at first order in the shape deformation, proportional to the integral of the null components of the stress tensor along the Rindler horizon. We use this fact along with monotonicity of relative entropy to prove the averaged null energy condition in Minkowski space-time. This subsequently gives a new proof of the Hofman-Maldacena bounds on the parameters appearing in CFT three-point functions. Our main technical advance involves adapting newly developed perturbative methods for calculating entanglement entropy to the problem at hand. These methods were recently used to prove certain results on the shape dependence of entanglement in CFTs and here we generalize these results to excited states and real time dynamics. We also discuss the AdS/CFT counterpart of this result, making connection with the recently proposed gravitational dual for modular Hamiltonians in holographic theories.

  2. OEDGE modeling of the DIII-D double null (CH4)-C-13 puffing experiment

    International Nuclear Information System (INIS)

    Elder, J.D.; Wampler, W.R.; McLean, A.G.; Stangeby, P.C.; Allen, S.L.; Bray, B.D.; Brooks, N.H.; Leonard, A.W.; Unterberg, Ezekial A.; Watkins, J.G.

    2011-01-01

    Unbalanced double null ELMy H-mode configurations in DIII-D are used to simulate the situation in ITER high triangularity, burning plasma magnetic equilibria, where the second X-point lies close to the top of the vacuum vessel, creating a secondary divertor region at the upper blanket modules. The measured plasma conditions in the outer secondary divertor closely duplicated those projected for ITER. (CH4)-C-13 was injected into the secondary outer divertor to simulate sputtering there. The majority of the C-13 found was in the secondary outer divertor. This material migration pattern is radically different than that observed for main wall (CH4)-C-13 injections into single null configurations where the deposition is primarily at the inner divertor. The implications for tritium codeposition resulting from sputtering at the secondary divertor in ITER are significant since release of tritium from Be co-deposits at the main wall bake temperature for ITER, 240 degrees C, is incomplete. The principal features of the measured C-13 deposition pattern have been replicated by the OEDGE interpretive code.

  3. Integrated optics for nulling interferometry in the thermal infrared: progress and recent achievements

    Science.gov (United States)

    Barillot, M.; Barthelemy, E.; Bastard, L.; Broquin, J.-E.; Hawkins, G.; Kirschner, V.; Ménard, S.; Parent, G.; Poinsot, C.; Pradel, A.; Vigreux, C.; Zhang, S.; Zhang, X.

    2017-11-01

    The search for Earth-like exoplanets, orbiting in the habitable zone of stars other than our Sun and showing biological activity, is one of the most exciting and challenging quests of the present time. Nulling interferometry from space, in the thermal infrared, appears as a promising candidate technique for the task of directly observing extra-solar planets. It has been studied for about 10 years by ESA and NASA in the framework of the Darwin and TPF-I missions respectively [1]. Nevertheless, nulling interferometry in the thermal infrared remains a technological challenge at several levels. Among them, the development of the "modal filter" function is mandatory for the filtering of the wavefronts in adequacy with the objective of rejecting the central star flux to an efficiency of about 105. Modal filtering [2] takes benefit of the capability of single-mode waveguides to transmit a single amplitude function, to eliminate virtually any perturbation of the interfering wavefronts, thus making very high rejection ratios possible. The modal filter may either be based on single-mode Integrated Optics (IO) and/or Fiber Optics. In this paper, we focus on IO, and more specifically on the progress of the on-going "Integrated Optics" activity of the European Space Agency.

  4. Cdk2-Null Mice Are Resistant to ErbB-2-Induced Mammary Tumorigenesis

    Directory of Open Access Journals (Sweden)

    Dipankar Ray

    2011-05-01

    Full Text Available The concept of targeting G1 cyclin-dependent kinases (CDKs in breast cancer treatments is supported by the fact that the genetic ablation of Cdk4 had minimal impacts on normal cell proliferation in majority of cell types, resulting in near-normal mouse development, whereas such loss of Cdk4 completely abrogated ErbB-2/neu-induced mammary tumorigenesis in mice. In most human breast cancer tissues, another G1-regulatory CDK, CDK2, is also hyperactivated by various mechanisms and is believed to be an important therapeutic target. In this report, we provide genetic evidence that CDK2 is essential for proliferation and oncogenesis of murine mammary epithelial cells. We observed that 87% of Cdk2-null mice were protected from ErbB-2-induced mammary tumorigenesis. Mouse embryonic fibroblasts isolated from Cdk2-null mouse showed resistance to various oncogene-induced transformation. Previously, we have reported that hemizygous loss of Cdc25A, the major activator of CDK2, can also protect mice from ErbB-2-induced mammary tumorigenesis [Cancer Res (2007 67(14: 6605–11]. Thus, we propose that CDC25A-CDK2 pathway is critical for the oncogenic action of ErbB-2 in mammary epithelial cells, in a manner similar to Cyclin D1/CDK4 pathway.

  5. Novel Remarks on Point Mass Sources, Firewalls, Null Singularities and Gravitational Entropy

    Science.gov (United States)

    Perelman, Carlos Castro

    2016-01-01

    A continuous family of static spherically symmetric solutions of Einstein's vacuum field equations with a spatial singularity at the origin r = 0 is found. These solutions are parametrized by a real valued parameter λ (ranging from 0 to 1) and such that the radial horizon's location is displaced continuously towards the singularity ( r = 0 ) as λ increases. In the extreme limit λ = 1, the location of the singularity and horizon merges leading to a null singularity. In this extreme case, any infalling observer hits the null singularity at the very moment he/she crosses the horizon. This fact may have important consequences for the resolution of the fire wall problem and the complementarity controversy in black holes. An heuristic argument is provided how one might avoid the Hawking particle emission process in this extreme case when the singularity and horizon merges. The field equations due to a delta-function point-mass source at r = 0 are solved and the Euclidean gravitational action corresponding to those solutions is evaluated explicitly. It is found that the Euclidean action is precisely equal to the black hole entropy (in Planck area units). This result holds in any dimensions D ≥ 3.

  6. NULLING DATA REDUCTION AND ON-SKY PERFORMANCE OF THE LARGE BINOCULAR TELESCOPE INTERFEROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Defrère, D.; Hinz, P. M.; Hoffmann, W. F.; Skemer, A. J.; Bailey, V.; Downey, E. C.; Durney, O.; Grenz, P.; McMahon, T. J.; Montoya, M.; Spalding, E.; Vaz, A.; Arbo, P.; Brusa, G. [Steward Observatory, Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Mennesson, B. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109-8099 (United States); Millan-Gabet, R. [NASA Exoplanet Science Institute, California Institute of Technology, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Danchi, W. C. [NASA Goddard Space Flight Center, Exoplanets and Stellar Astrophysics Laboratory, Code 667, Greenbelt, MD 20771 (United States); Hill, J. M. [Large Binocular Telescope Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Absil, O. [Institut d’Astrophysique et de Géophysique, Université de Liège, 19c Allée du Six Août, B-4000 Sart Tilman (Belgium); Bailey, H., E-mail: ddefrere@email.arizona.edu [Lunar and Planetary Laboratory, University of Arizona, 1541 E, University Boulevard, Tucson, AZ 85721 (United States); and others

    2016-06-20

    The Large Binocular Telescope Interferometer (LBTI) is a versatile instrument designed for high angular resolution and high-contrast infrared imaging (1.5–13 μ m). In this paper, we focus on the mid-infrared (8–13 μ m) nulling mode and present its theory of operation, data reduction, and on-sky performance as of the end of the commissioning phase in 2015 March. With an interferometric baseline of 14.4 m, the LBTI nuller is specifically tuned to resolve the habitable zone of nearby main-sequence stars, where warm exozodiacal dust emission peaks. Measuring the exozodi luminosity function of nearby main-sequence stars is a key milestone to prepare for future exo-Earth direct imaging instruments. Thanks to recent progress in wavefront control and phase stabilization, as well as in data reduction techniques, the LBTI demonstrated in 2015 February a calibrated null accuracy of 0.05% over a 3 hr long observing sequence on the bright nearby A3V star β Leo. This is equivalent to an exozodiacal disk density of 15–30 zodi for a Sun-like star located at 10 pc, depending on the adopted disk model. This result sets a new record for high-contrast mid-infrared interferometric imaging and opens a new window on the study of planetary systems.

  7. Positive, negative, or null? The effects of maternal incarceration on children's behavioral problems.

    Science.gov (United States)

    Wildeman, Christopher; Turney, Kristin

    2014-06-01

    We use data from the Fragile Families and Child Wellbeing Study to consider the effects of maternal incarceration on 21 caregiver- and teacher-reported behavioral problems among 9-year-old children. The results suggest three primary conclusions. First, children of incarcerated mothers are a disadvantaged group that exhibit high levels of caregiver- and teacher-reported behavioral problems. Second, after we adjust for selection, the effects of maternal incarceration on children's behavioral problems are consistently null (for 19 of 21 outcomes) and rarely positive (1 of 21) or negative (1 of 21), suggesting that the poor outcomes of these children are driven by disadvantages preceding maternal incarceration rather than incarceration. These effects, however, vary across race/ethnicity, with maternal incarceration diminishing caregiver-reported behavioral problems among non-Hispanic whites. Finally, in models considering both maternal and paternal incarceration, paternal incarceration is associated with more behavioral problems, which is consistent with previous research and suggests that the null effects of maternal incarceration are not artifacts of our sample or analytic decisions.

  8. Conformal gravity, the Einstein equations and spaces of complex null geodesics

    Energy Technology Data Exchange (ETDEWEB)

    Baston, R.J.; Mason, L.J.

    1987-07-01

    The aim of the paper is to give a twistorial characterisation of the field equations of conformal gravity and of Einstein spacetimes. Strong evidence is provided for a particularly concise characterisation of these equations in terms of 'formal neighbourhoods'of the space of complex null geodesics. Second-order perturbations of the metric of complexified Minkowski space are considered. These correspond to certain infinitesimal deformations of its space of complex null geodesics, PN. PN has a natural codimension one embedding into a larger space. It is shown that deformations extend automatically to the fourth-order embedding (that is, the fourth formal neighbourhood). They extend to the fifth formal neighbourhood if and only if the corresponding perturbation in the metric has vanishing Bach tensor. Finally, deformations which extend to the sixth formal neighbourhood correspond to perturbations in the metric that are conformally related to ones satisfying the Einstein equations. The authors present arguments which suggest that the results will also hold when spacetime is fully curved.

  9. Conformal gravity, the Einstein equations and spaces of complex null geodesics

    International Nuclear Information System (INIS)

    Baston, R.J.; Mason, L.J.

    1987-01-01

    The aim of the paper is to give a twistorial characterisation of the field equations of conformal gravity and of Einstein spacetimes. Strong evidence is provided for a particularly concise characterisation of these equations in terms of 'formal neighbourhoods'of the space of complex null geodesics. Second-order perturbations of the metric of complexified Minkowski space are considered. These correspond to certain infinitesimal deformations of its space of complex null geodesics, PN. PN has a natural codimension one embedding into a larger space. It is shown that deformations extend automatically to the fourth-order embedding (that is, the fourth formal neighbourhood). They extend to the fifth formal neighbourhood if and only if the corresponding perturbation in the metric has vanishing Bach tensor. Finally, deformations which extend to the sixth formal neighbourhood correspond to perturbations in the metric that are conformally related to ones satisfying the Einstein equations. The authors present arguments which suggest that the results will also hold when spacetime is fully curved. (author)

  10. Approaches for achieving broadband achromatic phase shifts for visible nulling coronagraphy

    Science.gov (United States)

    Bolcar, Matthew R.; Lyon, Richard G.

    2012-07-01

    Visible nulling coronagraphy is one of the few approaches to the direct detection and characterization of Jovian and Terrestrial exoplanets that works with segmented aperture telescopes. Jovian and Terrestrial planets require at least 10-9 and 10-10 image plane contrasts, respectively, within the spectral bandpass and thus require a nearly achromatic π-phase difference between the arms of the interferometer. An achromatic π-phase shift can be achieved by several techniques, including sequential angled thick glass plates of varying dispersive materials, distributed thin-film multilayer coatings, or techniques that leverage the polarization-dependent phase shift of total-internal reflections. Herein we describe two implementations of such techniques: sequential thick glass plates and Fresnel rhomb prisms. A viable technique must achieve the achromatic phase shift while simultaneously minimizing the intensity difference, chromatic beam spread and polarization variation between the interferometer arms. In this paper we describe the above implementations and report on the trades associated with each technique that will lead to an implementation of the most promising one in Goddard's Visible Nulling Coronagraph (VNC).

  11. Identifying the null subject: evidence from event-related brain potentials.

    Science.gov (United States)

    Demestre, J; Meltzer, S; García-Albea, J E; Vigil, A

    1999-05-01

    Event-related brain potentials (ERPs) were recorded during spoken language comprehension to study the on-line effects of gender agreement violations in controlled infinitival complements. Spanish sentences were constructed in which the complement clause contained a predicate adjective marked for syntactic gender. By manipulating the gender of the antecedent (i.e., the controller) of the implicit subject while holding constant the gender of the adjective, pairs of grammatical and ungrammatical sentences were created. The detection of such a gender agreement violation would indicate that the parser had established the coreference relation between the null subject and its antecedent. The results showed a complex biphasic ERP (i.e., an early negativity with prominence at anterior and central sites, followed by a centroparietal positivity) in the violating condition as compared to the non-violating conditions. The brain reacts to NP-adjective gender agreement violations within a few hundred milliseconds of their occurrence. The data imply that the parser has properly coindexed the null subject of an infinitive clause with its antecedent.

  12. Catastrophe in the stochastic layer due to dipole perturbation for a single-null divertor Tokamak

    International Nuclear Information System (INIS)

    Ali, H.; Watson, M.; Punjabi, A.; Boozer, A.

    1996-01-01

    We use the method of maps developed by Punjabi and Boozer to investigate the motion of magnetic field lines in stochastic scrape-off layer in the presence of dipole perturbation of a single-null divertor Tokamak. This method is based on the idea that the magnetic field line trajectories in a divertor tokamak are mathematically equivalent to a single degree of freedom, time dependent Hamiltonian System, and that the basic features of motion near a separatrix broadened by asymmetric perturbations are generic for such Hamiltonian and near-Hamiltonian systems. The magnetic topology of a single-null divertor tokamak with the effects on dipole perturbations is represented by the Symmetric Simple Map followed by Dipole Map. We have found that as the amplitude of the dipole perturbation increases, the width of the stochastic layer also increases. At some critical value of the amplitude is reached, there is a catastrophic increase in the width of stochastic layer. This may have significant implications for tokamak divertor physics

  13. Null stream analysis of Pulsar Timing Array data: localisation of resolvable gravitational wave sources

    Science.gov (United States)

    Goldstein, Janna; Veitch, John; Sesana, Alberto; Vecchio, Alberto

    2018-04-01

    Super-massive black hole binaries are expected to produce a gravitational wave (GW) signal in the nano-Hertz frequency band which may be detected by pulsar timing arrays (PTAs) in the coming years. The signal is composed of both stochastic and individually resolvable components. Here we develop a generic Bayesian method for the analysis of resolvable sources based on the construction of `null-streams' which cancel the part of the signal held in common for each pulsar (the Earth-term). For an array of N pulsars there are N - 2 independent null-streams that cancel the GW signal from a particular sky location. This method is applied to the localisation of quasi-circular binaries undergoing adiabatic inspiral. We carry out a systematic investigation of the scaling of the localisation accuracy with signal strength and number of pulsars in the PTA. Additionally, we find that source sky localisation with the International PTA data release one is vastly superior than what is achieved by its constituent regional PTAs.

  14. Seizure phenotypes, periodicity, and sleep-wake pattern of seizures in Kcna-1 null mice.

    Science.gov (United States)

    Wright, Samantha; Wallace, Eli; Hwang, Youngdeok; Maganti, Rama

    2016-02-01

    This study was undertaken to describe seizure phenotypes, natural progression, sleep-wake patterns, as well as periodicity of seizures in Kcna-1 null mutant mice. These mice were implanted with epidural electroencephalography (EEG) and electromyography (EMG) electrodes, and simultaneous video-EEG recordings were obtained while animals were individually housed under either diurnal (LD) condition or constant darkness (DD) over ten days of recording. The video-EEG data were analyzed to identify electrographic and behavioral phenotypes and natural progression and to examine the periodicity of seizures. Sleep-wake patterns were analyzed to understand the distribution and onset of seizures across the sleep-wake cycle. Four electrographically and behaviorally distinct seizure types were observed. Regardless of lighting condition that animals were housed in, Kcna-1 null mice initially expressed only a few of the most severe seizure types that progressively increased in frequency and decreased in seizure severity. In addition, a circadian periodicity was noted, with seizures peaking in the first 12h of the Zeitgeber time (ZT) cycle, regardless of lighting conditions. Interestingly, seizure onset differed between lighting conditions where more seizures arose out of sleep in LD conditions, whereas under DD conditions, the majority occurred out of the wakeful state. We suggest that this model be used to understand the circadian pattern of seizures as well as the pathophysiological implications of sleep and circadian disturbances in limbic epilepsies. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Disturbance of cardiac gene expression and cardiomyocyte structure predisposes Mecp2-null mice to arrhythmias

    Science.gov (United States)

    Hara, Munetsugu; Takahashi, Tomoyuki; Mitsumasu, Chiaki; Igata, Sachiyo; Takano, Makoto; Minami, Tomoko; Yasukawa, Hideo; Okayama, Satoko; Nakamura, Keiichiro; Okabe, Yasunori; Tanaka, Eiichiro; Takemura, Genzou; Kosai, Ken-ichiro; Yamashita, Yushiro; Matsuishi, Toyojiro

    2015-01-01

    Methyl-CpG-binding protein 2 (MeCP2) is an epigenetic regulator of gene expression that is essential for normal brain development. Mutations in MeCP2 lead to disrupted neuronal function and can cause Rett syndrome (RTT), a neurodevelopmental disorder. Previous studies reported cardiac dysfunction, including arrhythmias in both RTT patients and animal models of RTT. In addition, recent studies indicate that MeCP2 may be involved in cardiac development and dysfunction, but its role in the developing and adult heart remains unknown. In this study, we found that Mecp2-null ESCs could differentiate into cardiomyocytes, but the development and further differentiation of cardiovascular progenitors were significantly affected in MeCP2 deficiency. In addition, we revealed that loss of MeCP2 led to dysregulation of endogenous cardiac genes and myocardial structural alterations, although Mecp2-null mice did not exhibit obvious cardiac functional abnormalities. Furthermore, we detected methylation of the CpG islands in the Tbx5 locus, and showed that MeCP2 could target these sequences. Taken together, these results suggest that MeCP2 is an important regulator of the gene-expression program responsible for maintaining normal cardiac development and cardiomyocyte structure. PMID:26073556

  16. Canonical theory of spherically symmetric spacetimes with cross-streaming null dusts

    Science.gov (United States)

    Bičák, Jiří; Hájíček, Petr

    2003-11-01

    The Hamiltonian dynamics of two-component spherically symmetric null dust is studied with regard to the quantum theory of gravitational collapse. The components—the ingoing and outgoing dusts—are assumed to interact only through gravitation. Different kinds of singularities, naked or “clothed,” which can form during collapse processes are described. The general canonical formulation of the one-component null-dust dynamics by Bičák and Kuchař is restricted to the spherically symmetric case and used to construct an action for the two components. The transformation from a metric variable to the quasilocal mass is shown to simplify the mathematics. The action is reduced by a choice of gauge and the corresponding true Hamiltonian is written down. Asymptotic coordinates and energy densities of dust shells are shown to form a complete set of Dirac observables. The action of the asymptotic time translation on the observables is defined but it has been calculated explicitly only in the case of one-component dust (Vaidya metric).

  17. Developmental plasticity: re-conceiving the genotype.

    Science.gov (United States)

    Sultan, Sonia E

    2017-10-06

    In recent decades, the phenotype of an organism (i.e. its traits and behaviour) has been studied as the outcome of a developmental 'programme' coded in its genotype. This deterministic view is implicit in the Modern Synthesis approach to adaptive evolution as a sorting process among genetic variants. Studies of developmental pathways have revealed that genotypes are in fact differently expressed depending on environmental conditions. Accordingly, the genotype can be understood as a repertoire of potential developmental outcomes or norm of reaction. Reconceiving the genotype as an environmental response repertoire rather than a fixed developmental programme leads to three critical evolutionary insights. First, plastic responses to specific conditions often comprise functionally appropriate trait adjustments, resulting in an individual-level, developmental mode of adaptive variation. Second, because genotypes are differently expressed depending on the environment, the genetic diversity available to natural selection is itself environmentally contingent. Finally, environmental influences on development can extend across multiple generations via cytoplasmic and epigenetic factors transmitted to progeny individuals, altering their responses to their own, immediate environmental conditions and, in some cases, leading to inherited but non-genetic adaptations. Together, these insights suggest a more nuanced understanding of the genotype and its evolutionary role, as well as a shift in research focus to investigating the complex developmental interactions among genotypes, environments and previous environments.

  18. Calculation of null points in SPAIR, FLAIR, and STIR. Part 2. Application to pelvic diffusion-weighted imaging with SPAIR at 3T

    International Nuclear Information System (INIS)

    Kita, Miho; Kawano, Kazuhiro; Kometani, Katsuya; Kondo, Toshihiko; Shimamoto, Kazuhiro; Tanaka, Humihiro; Oda, Hideyuki; Kojima, Akihiro; Sato, Morio

    2013-01-01

    Diffusion-weighted imaging (DWI) requires adequate fat suppression because of its sensitivity to chemical shift artifacts, especially at 3 Tesla (T). We investigated the utility of calculating the inversion time of the null point (TI null ) in pelvic DWI with spectral attenuated inversion recovery (SPAIR) at 3 T for obtaining adequate fat suppression. Thirteen volunteers underwent pelvic SPAIR-DWI using various SPAIR inversion delay times (TI) at 5-ms intervals in the range of the calculated TI null ±25 ms. The degree of fat suppression was evaluated into 3 grades and was compared among the various SPAIR-TIs with the calculated TI null . In 65 cases of prostatic disease, we evaluated the ratio of adequate fat suppression obtained using the calculated TI null . We obtained adequate fat suppression in all 13 volunteers and in 61 (94%) of the 65 patients using the calculated TI null . Fat suppression was best when the calculated TI null was used (P null (P null increased. In conclusion, this method of calculating the TI null may be useful for obtaining adequate fat suppression for pelvic SPAIR-DWI at 3T. (author)

  19. Genotype X/C recombinant (putative genotype I) of hepatitis B virus is rare in Hanoi, Vietnam--genotypes B4 and C1 predominate.

    Science.gov (United States)

    Phung, Thi Bich Thuy; Alestig, Erik; Nguyen, Thanh Liem; Hannoun, Charles; Lindh, Magnus

    2010-08-01

    There are eight known genotypes of hepatitis B virus, A-H, and several subgenotypes, with rather well-defined geographic distributions. HBV genotypes were evaluated in 153 serum samples from Hanoi, Vietnam. Of the 87 samples that could be genotyped, genotype B was found in 67 (77%) and genotype C in 19 (22%). All genotype C strains were of subgenotype C1, and the majority of genotype B strains were B4, while a few were B2. The genotype X/C recombinant strain, identified previously in Swedish patients of indigenous Vietnamese origin, was found in one sample. This variant, proposed to be classified as genotype I, has been found recently also by others in Vietnam and Laos. The current study indicates that the genotype X/C recombinant may represent approximately 1% of the HBV strains circulating in Vietnam. (c) 2010 Wiley-Liss, Inc.

  20. Quantitative trait loci for a neurocranium deformity, lack of operculum, in gilthead seabream (Sparus aurata L.).

    Science.gov (United States)

    Negrín-Báez, D; Navarro, A; Afonso, J M; Toro, M A; Zamorano, M J

    2016-04-01

    Lack of operculum, a neurocranial deformity, is the most common external abnormality to be found among industrially produced gilthead seabream (Sparus aurata L.), and this entails significant financial losses. This study conducts, for the first time in this species, a quantitative trait loci (QTL) analysis of the lack of operculum. A total of 142 individuals from a paternal half-sibling family (six full-sibling families) were selected for QTL mapping. They had previously shown a highly significant association with the prevalence of lack of operculum in a segregation analysis. All the fish were genotyped for 106 microsatellite markers using a set of multiplex PCRs (ReMsa1-ReMsa13). A linear regression methodology was used for the QTL analysis. Four QTL were detected for this deformity, two of which (QTLOP1 and QTLOP2) were significant. They were located at LG (linkage group) nine and LG10 respectively. Both QTL showed a large effect (about 27%), and furthermore, the association between lack of operculum and sire allelic segregation observed was statistically significant in the QTLOP1 analysis. These results represent a significant step towards including marker-assisted selection for this deformity in genetic breeding programmes to reduce the incidence of the deformity in the species. © 2016 Stichting International Foundation for Animal Genetics.

  1. No actual measurement … was required: Maxwell and Cavendish's null method for the inverse square law of electrostatics.

    Science.gov (United States)

    Falconer, Isobel

    In 1877 James Clerk Maxwell and his student Donald MacAlister refined Henry Cavendish's 1773 null experiment demonstrating the absence of electricity inside a charged conductor. This null result was a mathematical prediction of the inverse square law of electrostatics, and both Cavendish and Maxwell took the experiment as verifying the law. However, Maxwell had already expressed absolute conviction in the law, based on results of Michael Faraday's. So, what was the value to him of repeating Cavendish's experiment? After assessing whether the law was as secure as he claimed, this paper explores its central importance to the electrical programme that Maxwell was pursuing. It traces the historical and conceptual re-orderings through which Maxwell established the law by constructing a tradition of null tests and asserting the superior accuracy of the method. Maxwell drew on his developing 'doctrine of method' to identify Cavendish's experiment as a member of a wider class of null methods. By doing so, he appealed to the null practices of telegraph engineers, diverted attention from the flawed logic of the method, and sought to localise issues around the mapping of numbers onto instrumental indications, on the grounds that 'no actual measurement … was required'. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Limit structure of future null infinity tangent-topology of the event horizon and gravitational wave tail

    International Nuclear Information System (INIS)

    Tomizawa, Shinya; Siino, Masaru

    2006-01-01

    We investigated the relation between the behaviour of gravitational waves at late time and the limit structure of future null infinity tangent which will determine the topology of the event horizon far in the future. In the present paper, we mainly consider a spacetime with two black holes. Although in most cases, the black holes coalesce and the event horizon is topologically a single sphere far in the future, there are several possibilities that the black holes never coalesce and such exact solutions as examples. In our formulation, the tangent vector of future null infinity is, under conformal embedding, related to the number of black holes far in the future through the Poincare-Hopf theorem. Under the conformal embedding, the topology of the event horizon far in the future will be affected by the geometrical structure of the future null infinity. In this paper, we relate the behaviour of Weyl curvature to this limit behaviour of the generator vector of the future null infinity. We show if Weyl curvature decays sufficiently slowly at late time in the neighbourhood of future null infinity, two black holes never coalesce

  3. Influence of GSTM1 and GSTT1 genotypes and confounding factors on the frequency of sister chromatid exchange and micronucleus among road construction workers.

    Science.gov (United States)

    Kumar, Anil; Yadav, Anita; Giri, Shiv Kumar; Dev, Kapil; Gautam, Sanjeev Kumar; Gupta, Ranjan; Aggarwal, Neeraj

    2011-07-01

    In the present study, we have investigated the influence of polymorphism of GSTM1 and GSTT1 genes and confounding factors such as age, sex, exposure duration and consumption habits on cytogenetic biomarkers. Frequency of sister chromatid exchanges (SCEs), high frequency cell (HFC) and cytokinesis blocked micronuclei (CBMN) were evaluated in peripheral blood lymphocytes of 115 occupationally exposed road construction workers and 105 unexposed individuals. The distribution of null and positive genotypes of glutathione-S transferase gene was evaluated by multiplex PCR among control and exposed subjects. An increased frequency of CBMN (7.03±2.08); SCE (6.95±1.76) and HFC (6.28±1.69) were found in exposed subjects when compared to referent (CBMN - 3.35±1.10; SCE - 4.13±1.30 and HFC - 3.98±1.56). These results were found statistically significant at p<0.05. When the effect of confounding factors on the frequency of studied biomarkers was evaluated, a strong positive interaction was found. The individuals having GSTM1 and GSTT1 null genotypes had higher frequency of CBMN, SCE and HFC. The association between GSTM1 and GSTT1 genotypes and studied biomarkers was found statistically significant at p<0.05. Our findings suggest that individuals having null type of GST are more susceptible to cytogenetic damage by occupational exposure regardless of confounding factors. There is a significant effect of polymorphism of these genes on cytogenetic biomarkers which are considered as early effects of genotoxic carcinogens. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Evolution of Dengue Virus Type 3 Genotype III in Venezuela: Diversification, Rates and Population Dynamics

    Science.gov (United States)

    2010-01-01

    Background Dengue virus (DENV) is a member of the genus Flavivirus of the family Flaviviridae. DENV are comprised of four distinct serotypes (DENV-1 through DENV-4) and each serotype can be divided in different genotypes. Currently, there is a dramatic emergence of DENV-3 genotype III in Latin America. Nevertheless, we still have an incomplete understanding of the evolutionary forces underlying the evolution of this genotype in this region of the world. In order to gain insight into the degree of genetic variability, rates and patterns of evolution of this genotype in Venezuela and the South American region, phylogenetic analysis, based on a large number (n = 119) of envelope gene sequences from DENV-3 genotype III strains isolated in Venezuela from 2001 to 2008, were performed. Results Phylogenetic analysis revealed an in situ evolution of DENV-3 genotype III following its introduction in the Latin American region, where three different genetic clusters (A to C) can be observed among the DENV-3 genotype III strains circulating in this region. Bayesian coalescent inference analyses revealed an evolutionary rate of 8.48 × 10-4 substitutions/site/year (s/s/y) for strains of cluster A, composed entirely of strains isolated in Venezuela. Amino acid substitution at position 329 of domain III of the E protein (A→V) was found in almost all E proteins from Cluster A strains. Conclusions A significant evolutionary change between DENV-3 genotype III strains that circulated in the initial years of the introduction in the continent and strains isolated in the Latin American region in recent years was observed. The presence of DENV-3 genotype III strains belonging to different clusters was observed in Venezuela, revealing several introduction events into this country. The evolutionary rate found for Cluster A strains circulating in Venezuela is similar to the others previously established for this genotype in other regions of the world. This suggests a lack of correlation

  5. Evolution of Dengue Virus Type 3 Genotype III in Venezuela: Diversification, Rates and Population Dynamics

    Directory of Open Access Journals (Sweden)

    Moratorio Gonzalo

    2010-11-01

    lack of correlation among DENV genotype III substitution rate and ecological pattern of virus spread.

  6. Molecular characterization of Echinococcus granulosus cysts in north Indian patients: identification of G1, G3, G5 and G6 genotypes.

    Directory of Open Access Journals (Sweden)

    Monika Sharma

    Full Text Available BACKGROUND: Cystic echinococcosis (CE caused by the Echinococcus granulosus, is a major public health problem worldwide, including India. The different genotypes of E. granulosus responsible for human hydatidosis have been reported from endemic areas throughout the world. However, the genetic characterization of E. granulosus infecting the human population in India is lacking. The aim of study was to ascertain the genotype(s of the parasite responsible for human hydatidosis in North India. METHODOLOGY/PRINCIPAL FINDINGS: To study the transmission patterns of E. granulosus, genotypic analysis was performed on hydatid cysts obtained from 32 cystic echinococcosis (CE patients residing in 7 different states of North India. Mitochondrial cytochrome c oxidase subunit1 (cox1 sequencing was done for molecular identification of the isolates. Most of the CE patients (30/32 were found to be infected with hydatid cyst of either G3 (53.1% or G1 (40.62% genotype and one each of G5 (cattle strain and G6 (camel strain genotype. CONCLUSIONS/SIGNIFICANCE: These findings demonstrate the zoonotic potential of G1 (sheep strain and G3 (buffalo strain genotypes of E. granulosus as these emerged as predominant genotypes infecting the humans in India. In addition to this, the present study reports the first human CE case infected with G5 genotype (cattle strain in an Asian country and presence of G6 genotype (camel strain in India. The results may have important implications in the planning of control strategies for human hydatidosis.

  7. Molecular Characterization of Echinococcus granulosus Cysts in North Indian Patients: Identification of G1, G3, G5 and G6 Genotypes

    Science.gov (United States)

    Sharma, Monika; Sehgal, Rakesh; Fomda, Bashir Ahmad; Malhotra, Anil; Malla, Nancy

    2013-01-01

    Background Cystic echinococcosis (CE) caused by the Echinococcus granulosus, is a major public health problem worldwide, including India. The different genotypes of E. granulosus responsible for human hydatidosis have been reported from endemic areas throughout the world. However, the genetic characterization of E. granulosus infecting the human population in India is lacking. The aim of study was to ascertain the genotype(s) of the parasite responsible for human hydatidosis in North India. Methodology/Principal Findings To study the transmission patterns of E. granulosus, genotypic analysis was performed on hydatid cysts obtained from 32 cystic echinococcosis (CE) patients residing in 7 different states of North India. Mitochondrial cytochrome c oxidase subunit1 (cox1) sequencing was done for molecular identification of the isolates. Most of the CE patients (30/32) were found to be infected with hydatid cyst of either G3 (53.1%) or G1 (40.62%) genotype and one each of G5 (cattle strain) and G6 (camel strain) genotype. Conclusions/Significance These findings demonstrate the zoonotic potential of G1 (sheep strain) and G3 (buffalo strain) genotypes of E. granulosus as these emerged as predominant genotypes infecting the humans in India. In addition to this, the present study reports the first human CE case infected with G5 genotype (cattle strain) in an Asian country and presence of G6 genotype (camel strain) in India. The results may have important implications in the planning of control strategies for human hydatidosis. PMID:23785531

  8. Hepatitis B virus genotypes circulating in Brazil: molecular characterization of genotype F isolates

    Directory of Open Access Journals (Sweden)

    Virgolino Helaine A

    2007-11-01

    Full Text Available Abstract Background Hepatitis B virus (HBV isolates have been classified in eight genotypes, A to H, which exhibit distinct geographical distributions. Genotypes A, D and F are predominant in Brazil, a country formed by a miscegenated population, where the proportion of individuals from Caucasian, Amerindian and African origins varies by region. Genotype F, which is the most divergent, is considered indigenous to the Americas. A systematic molecular characterization of HBV isolates from different parts of the world would be invaluable in establishing HBV evolutionary origins and dispersion patterns. A large-scale study is needed to map the region-by-region distribution of the HBV genotypes in Brazil. Results Genotyping by PCR-RFLP of 303 HBV isolates from HBsAg-positive blood donors showed that at least two of the three genotypes, A, D, and F, co-circulate in each of the five geographic regions of Brazil. No other genotypes were identified. Overall, genotype A was most prevalent (48.5%, and most of these isolates were classified as subgenotype A1 (138/153; 90.2%. Genotype D was the most common genotype in the South (84.2% and Central (47.6% regions. The prevalence of genotype F was low (13% countrywide. Nucleotide sequencing of the S gene and a phylogenetic analysis of 32 HBV genotype F isolates showed that a great majority (28/32; 87.5% belonged to subgenotype F2, cluster II. The deduced serotype of 31 of 32 F isolates was adw4. The remaining isolate showed a leucine-to-isoleucine substitution at position 127. Conclusion The presence of genotypes A, D and F, and the absence of other genotypes in a large cohort of HBV infected individuals may reflect the ethnic origins of the Brazilian population. The high prevalence of isolates from subgenotype A1 (of African origin indicates that the African influx during the colonial slavery period had a major impact on the circulation of HBV genotype A currently found in Brazil. Although most genotype F

  9. Forensic SNP genotyping with SNaPshot

    DEFF Research Database (Denmark)

    Fondevila, M; Børsting, C; Phillips, C

    2017-01-01

    to routine STR profiling, use of SNaPshot is an important part of the development of SNP sets for a wide range of forensic applications with these markers, from genotyping highly degraded DNA with very short amplicons to the introduction of SNPs to ascertain the ancestry and physical characteristics......This review explores the key factors that influence the optimization, routine use, and profile interpretation of the SNaPshot single-base extension (SBE) system applied to forensic single-nucleotide polymorphism (SNP) genotyping. Despite being a mainly complimentary DNA genotyping technique...... of an unidentified contact trace donor. However, this technology, as resourceful as it is, displays several features that depart from the usual STR genotyping far enough to demand a certain degree of expertise from the forensic analyst before tackling the complex casework on which SNaPshot application provides...

  10. HMSRP Hawaiian Monk Seal Microsatellite Genotypes

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Currently ~2,400 Hawaiian monk seal specimens have been analyzed genetically, providing genotypes at 18 microsatellite loci. These data are organized by individual,...

  11. Global distribution of novel rhinovirus genotype

    DEFF Research Database (Denmark)

    Briese, Thomas; Renwick, Neil; Venter, Marietjie

    2008-01-01

    Global surveillance for a novel rhinovirus genotype indicated its association with community outbreaks and pediatric respiratory disease in Africa, Asia, Australia, Europe, and North America. Molecular dating indicates that these viruses have been circulating for at least 250 years Udgivelsesdato...

  12. Assessment of antibiotic susceptibilities, genotypic characteristics ...

    African Journals Online (AJOL)

    Jane

    2011-09-28

    Sep 28, 2011 ... Staphylococcus aureus and Salmonella Typhimurium ... This study was designed to evaluate the antibiotic susceptibilities, genotypic characteristics and ..... Distribution of reference and virulence genes among antibiotic-sensitive S. aureus (SAS), .... environmental factors such as temperature, water activity,.

  13. Hepatitis C Virus: Viral Quasispecies and Genotypes

    Directory of Open Access Journals (Sweden)

    Kyoko Tsukiyama-Kohara

    2017-12-01

    Full Text Available Hepatitis C virus (HCV mainly replicates in the cytoplasm, where it easily establishes persistent infection, resulting in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Due to its high rate of mutation, HCV forms viral quasispecies, categorized based on the highly variable regions in the envelope protein and nonstructural 5A protein. HCV possesses seven major genotypes, among which genotype 1 is the most prevalent globally. The distribution of HCV genotypes varies based on geography, and each genotype has a different sensitivity to interferon treatment. Recently-developed direct-acting antivirals (DAAs, which target viral proteases or polymerases, mediate drastically better antiviral effects than previous therapeutics. Although treatment with DAAs has led to the development of drug-resistant HCV mutants, the most recently approved DAAs show improved pan-genomic activity, with a higher barrier to viral resistance.

  14. Hepatitis C Virus: Viral Quasispecies and Genotypes.

    Science.gov (United States)

    Tsukiyama-Kohara, Kyoko; Kohara, Michinori

    2017-12-22

    Hepatitis C virus (HCV) mainly replicates in the cytoplasm, where it easily establishes persistent infection, resulting in chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. Due to its high rate of mutation, HCV forms viral quasispecies, categorized based on the highly variable regions in the envelope protein and nonstructural 5A protein. HCV possesses seven major genotypes, among which genotype 1 is the most prevalent globally. The distribution of HCV genotypes varies based on geography, and each genotype has a different sensitivity to interferon treatment. Recently-developed direct-acting antivirals (DAAs), which target viral proteases or polymerases, mediate drastically better antiviral effects than previous therapeutics. Although treatment with DAAs has led to the development of drug-resistant HCV mutants, the most recently approved DAAs show improved pan-genomic activity, with a higher barrier to viral resistance.

  15. Early seedling development of Medicago truncatula genotypes ...

    African Journals Online (AJOL)

    adel

    2014-01-08

    Jan 8, 2014 ... heat shock proteins; ABA, abscisic acid. Page 2. Amar et al. 323. Figure 1. Seed vigor of M. truncatula genotypes under different salt stress conditions. Results are means ..... (HSPs) that accumulate during seed late maturation.

  16. Hearing impairment in genotyped Wolfram syndrome patients.

    NARCIS (Netherlands)

    Plantinga, R.F.; Pennings, R.J.E.; Huygen, P.L.M.; Bruno, R.; Eller, P.; Barrett, T.G.; Vialettes, B.; Paquis-Fluklinger, V.; Lombardo, F.; Cremers, C.W.R.J.

    2008-01-01

    OBJECTIVES: Wolfram syndrome is a progressive neurodegenerative syndrome characterized by the features "DIDMOAD" (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness). We sought to study the audiometric data of genotyped Wolfram syndrome patients with sensorineural hearing impairment.

  17. A Solution Space for a System of Null-State Partial Differential Equations: Part 2

    Science.gov (United States)

    Flores, Steven M.; Kleban, Peter

    2015-01-01

    This article is the second of four that completely and rigorously characterize a solution space for a homogeneous system of 2 N + 3 linear partial differential equations in 2 N variables that arises in conformal field theory (CFT) and multiple Schramm-Löwner evolution (SLE). The system comprises 2 N null-state equations and three conformal Ward identities which govern CFT correlation functions of 2 N one-leg boundary operators. In the first article (Flores and Kleban, Commun Math Phys, arXiv:1212.2301, 2012), we use methods of analysis and linear algebra to prove that dim , with C N the Nth Catalan number. The analysis of that article is complete except for the proof of a lemma that it invokes. The purpose of this article is to provide that proof. The lemma states that if every interval among ( x 2, x 3), ( x 3, x 4),…,( x 2 N-1, x 2 N ) is a two-leg interval of (defined in Flores and Kleban, Commun Math Phys, arXiv:1212.2301, 2012), then F vanishes. Proving this lemma by contradiction, we show that the existence of such a nonzero function implies the existence of a non-vanishing CFT two-point function involving primary operators with different conformal weights, an impossibility. This proof (which is rigorous in spite of our occasional reference to CFT) involves two different types of estimates, those that give the asymptotic behavior of F as the length of one interval vanishes, and those that give this behavior as the lengths of two intervals vanish simultaneously. We derive these estimates by using Green functions to rewrite certain null-state PDEs as integral equations, combining other null-state PDEs to obtain Schauder interior estimates, and then repeatedly integrating the integral equations with these estimates until we obtain optimal bounds. Estimates in which two interval lengths vanish simultaneously divide into two cases: two adjacent intervals and two non-adjacent intervals. The analysis of the latter case is similar to that for one vanishing

  18. Nulling interferometry: impact of exozodiacal clouds on the performance of future life-finding space missions

    Science.gov (United States)

    Defrère, D.; Absil, O.; den Hartog, R.; Hanot, C.; Stark, C.

    2010-01-01

    Context. Earth-sized planets around nearby stars are being detected for the first time by ground-based radial velocity and space-based transit surveys. This milestone is opening the path toward the definition of instruments able to directly detect the light from these planets, with the identification of bio-signatures as one of the main objectives. In that respect, both the European Space Agency (ESA) and the National Aeronautics and Space Administration (NASA) have identified nulling interferometry as one of the most promising techniques. The ability to study distant planets will however depend on the amount of exozodiacal dust in the habitable zone of the target stars. Aims: We assess the impact of exozodiacal clouds on the performance of an infrared nulling interferometer in the Emma X-array configuration. The first part of the study is dedicated to the effect of the disc brightness on the number of targets that can be surveyed and studied by spectroscopy during the mission lifetime. In the second part, we address the impact of asymmetric structures in the discs such as clumps and offset which can potentially mimic the planetary signal. Methods: We use the DarwinSIM software which was designed and validated to study the performance of space-based nulling interferometers. The software has been adapted to handle images of exozodiacal discs and to compute the corresponding demodulated signal. Results: For the nominal mission architecture with 2-m aperture telescopes, centrally symmetric exozodiacal dust discs about 100 times denser than the solar zodiacal cloud can be tolerated in order to survey at least 150 targets during the mission lifetime. Considering modeled resonant structures created by an Earth-like planet orbiting at 1 AU around a Sun-like star, we show that this tolerable dust density goes down to about 15 times the solar zodiacal density for face-on systems and decreases with the disc inclination. Conclusions: Whereas the disc brightness only affects

  19. Human PTCHD3 nulls: rare copy number and sequence variants suggest a non-essential gene

    Directory of Open Access Journals (Sweden)

    Lionel Anath C

    2011-03-01

    Full Text Available Abstract Background Copy number variations (CNVs can contribute to variable degrees of fitness and/or disease predisposition. Recent studies show that at least 1% of any given genome is copy number variable when compared to the human reference sequence assembly. Homozygous deletions (or CNV nulls that are found in the normal population are of particular interest because they may serve to define non-essential genes in human biology. Results In a genomic screen investigating CNV in Autism Spectrum Disorders (ASDs we detected a heterozygous deletion on chromosome 10p12.1, spanning the Patched-domain containing 3 (PTCHD3 gene, at a frequency of ~1.4% (6/427. This finding seemed interesting, given recent discoveries on the role of another Patched-domain containing gene (PTCHD1 in ASD. Screening of another 177 ASD probands yielded two additional heterozygous deletions bringing the frequency to 1.3% (8/604. The deletion was found at a frequency of ~0.73% (27/3,695 in combined control population from North America and Northern Europe predominately of European ancestry. Screening of the human genome diversity panel (HGDP-CEPH covering worldwide populations yielded deletions in 7/1,043 unrelated individuals and those detected were confined to individuals of European/Mediterranean/Middle Eastern ancestry. Breakpoint mapping yielded an identical 102,624 bp deletion in all cases and controls tested, suggesting a common ancestral event. Interestingly, this CNV occurs at a break of synteny between humans and mouse. Considering all data, however, no significant association of these rare PTCHD3 deletions with ASD was observed. Notwithstanding, our RNA expression studies detected PTCHD3 in several tissues, and a novel shorter isoform for PTCHD3 was characterized. Expression in transfected COS-7 cells showed PTCHD3 isoforms colocalize with calnexin in the endoplasmic reticulum. The presence of a patched (Ptc domain suggested a role for PTCHD3 in various biological

  20. Chemical changes in DMP1-null murine bone & silica based pecvd coatings for titanium implant osseoapplications

    Science.gov (United States)

    Maginot, Megen

    In order to improve clinical outcomes in bone-implant systems, a thorough understanding of both local bone chemistry and implant surface chemistry is necessary. This study consists, therefore, of two main parts: one focused on determining the nature of the changes in bone chemistry in a DMP1-null transgenic disease model and the other on the development of amorphous silica-based coatings for potential use as titanium bone implant coatings. For the study of bone mineral in the DMP1 transgenic model, which is known to have low serum phosphate levels, transgenic DMP1-null and wild type mice were fed a high phosphate diet, sacrificed, and had their long bone harvested. This bone was characterized using SEM, FTIR, microCT and XANES and compared to DMP1-null and wild type control groups to assess the therapeutic effect of high Pi levels on the phenotype and the role of DMP1 in mineralization in vivo. Findings suggest that though the high phosphate diet results in restoring serum phosphate levels, it does not completely rescue the bone mineral phenotype at an ultrastructural level and implicates DMP1 in phosphate nucleation. Since plasma enhanced chemical vapor deposition (PECVD) silica like coatings have not previously been fabricated for use in oessoapplications, the second part of this study initially focused on the characterization of novel SiOx chemistries fabricated via a chemical vapor deposition process that were designed specifically to act as bioactive coatings with a loose, hydrogenated structure. These coatings were then investigated for their potential initial stage response to bone tissue through immersion in a simulated body fluid and through the culture of MC3T3 cells on the coating surfaces. Coating surfaces were characterized by SEM, FTIR, contact angle measurements, and XANES. Coating dissolution and ionic release were also investigated by ICP-OES. Findings suggest that some SiOx chemistries may form a bioactive coating while more highly substituted

  1. Myostatin genotype regulates muscle-specific miRNA expression in mouse pectoralis muscle

    Directory of Open Access Journals (Sweden)

    Cheng Ye

    2010-11-01

    Full Text Available Abstract Background Loss of functional Myostatin results in a dramatic increase in skeletal muscle mass. It is unknown what role miRNAs play in Myostatin mediated repression of skeletal muscle mass. We hypothesized that Myostatin genotype would be associated with the differential expression of miRNAs in skeletal muscle. Findings Loss of functional Myostatin resulted in a significant increase (p .2 on miR-24 expression level. Myostatin genotype did not affect the expression level of MyoD or Myogenin (P > 0.5. Conclusions Myostatin may regulates the expression of miRNAs such as miR-133a, miR-133b, miR-1, and miR-206 in skeletal muscle as it has been observed that the expression of those miRNAs are significantly higher in myostatin null mice compared to wild type and heterozygous mice. In contrast, expression of myogenic factors such as MyoD or Myogenin has not been affected by myostatin in the muscle tissue.

  2. Existence of various human parvovirus B19 genotypes in Chinese plasma pools: genotype 1, genotype 3, putative intergenotypic recombinant variants and new genotypes.

    Science.gov (United States)

    Jia, Junting; Ma, Yuyuan; Zhao, Xiong; Huangfu, Chaoji; Zhong, Yadi; Fang, Chi; Fan, Rui; Lv, Maomin; Zhang, Jingang

    2016-09-17

    Human parvovirus B19 (B19V) is a frequent contaminant of blood and plasma-derived medicinal products. Three distinct genotypes of B19V have been identified. The distribution of the three B19V genotypes has been investigated in various regions or countries. However, in China, data on the existence of different B19V genotypes are limited. One hundred and eighteen B19V-DNA positive source plasma pool samples collected from three Chinese blood products manufacturers were analyzed. The subgenomic NS1/VP1u region junction of B19V was amplified by nested PCR. These amplified products were then cloned and subsequently sequenced. For genotyping, their phylogenetic inferences were constructed based on the NS1/VP1-unique region. Then putative recombination events were analyzed and identified. Phylogenetic analysis of 118 B19V sequences attributed 61.86 % to genotype 1a, 10.17 % to genotype 1b, and 17.80 % to genotype 3b. All the genotype 3b sequences obtained in this study grouped as a specific, closely related cluster with B19V strain D91.1. Four 1a/3b recombinants and 5 new atypical B19V variants with no recombination events were identified. There were at least 3 subtypes (1a, 1b and 3b) of B19V circulating in China. Furthermore, putative B19V 1a/3b recombinants and unclassified strains were identified as well. Such recombinant and unclassified strains may contribute to the genetic diversity of B19V and consequently complicate the B19V infection diagnosis and NAT screening. Further studies will be required to elucidate the biological significance of the recombinant and unclassified strains.

  3. Three genes for mitochondrial proteins suppress null-mutations in both Afg3 and Rca1 when over-expressed.

    Science.gov (United States)

    Rep, M; Nooy, J; Guélin, E; Grivell, L A

    1996-08-01

    The AFG3 gene of Saccharomyces cerevisiae encodes a mitochondrial inner membrane protein with ATP-dependent protease activity. To gain more insight into the function of this protein, multi-copy suppressors of an afg3-null mutation were isolated. Three genes were found that restored partial growth on non-fermentable carbon sources, all of which affect the biogenesis of respiratory competent mitochondria: PIM1(LON) encodes a matrix-localized ATP-dependent protease involved in the turnover of matrix proteins; OXA1(PET1402) encodes a putative mitochondrial inner membrane protein involved in the biogenesis of the respiratory chain; and MBA1 encodes a mitochondrial protein required for optimal respiratory growth. All three genes also suppressed a null mutation in a related gene, RCA1, as well as in the combination of afg3- and rca1-null.

  4. Generalized Robertson-Walker Space-Time Admitting Evolving Null Horizons Related to a Black Hole Event Horizon.

    Science.gov (United States)

    Duggal, K L

    2016-01-01

    A new technique is used to study a family of time-dependent null horizons, called " Evolving Null Horizons " (ENHs), of generalized Robertson-Walker (GRW) space-time [Formula: see text] such that the metric [Formula: see text] satisfies a kinematic condition. This work is different from our early papers on the same issue where we used (1 + n )-splitting space-time but only some special subcases of GRW space-time have this formalism. Also, in contrast to previous work, we have proved that each member of ENHs is totally umbilical in [Formula: see text]. Finally, we show that there exists an ENH which is always a null horizon evolving into a black hole event horizon and suggest some open problems.

  5. Popcorn genotypes resistance to fall armyworm

    Directory of Open Access Journals (Sweden)

    Nádia Cristina de Oliveira

    2018-02-01

    Full Text Available ABSTRACT: The aim of this study was to evaluate popcorn genotypes for resistance to the fall armyworm, Spodoptera frugiperda. The experiment used a completely randomized design with 30 replicates. The popcorn genotypes Aelton, Arzm 05 083, Beija-Flor, Colombiana, Composto Chico, Composto Gaúcha, Márcia, Mateus, Ufvm Barão Viçosa, Vanin, and Viviane were evaluated,along with the common maize variety Zapalote Chico. Newly hatched fall armyworm larvae were individually assessed with regard to biological development and consumption of food. The data were subjected to multivariate analyses of variance and genetic divergence among genotypes was evaluated through the clustering methods of Tocher based on generalized Mahalanobis distances and canonical variable analyses. Seven popcorn genotypes, namely, Aelton, Arzm 05 083, Composto Chico, Composto Gaúcha, Márcia, Mateus, and Viviane,were shown to form a cluster (cluster I that had antibiosis as the mechanism of resistance to the pest. Cluster I genotypes and the Zapalote Chico genotype could be used for stacking genes for antibiosis and non-preference resistance.

  6. Metal components analysis of metallothionein-III in the brain sections of metallothionein-I and metallothionein-II null mice exposed to mercury vapor with HPLC/ICP-MS

    Energy Technology Data Exchange (ETDEWEB)

    Kameo, Satomi; Nakai, Kunihiko; Kurokawa, Naoyuki; Satoh, Hiroshi [Tohoku University, Graduate School of Medicine, Aoba-ku, Sendai (Japan); Kanehisa, Tomokazu; Naganuma, Akira [Tohoku University, Graduate School of Pharmaceutical Sciences, Sendai (Japan)

    2005-04-01

    Mercury vapor is effectively absorbed via inhalation and easily passes through the blood-brain barrier; therefore, mercury poisoning with primarily central nervous system symptoms occurs. Metallothionein (MT) is a cysteine-rich metal-binding protein and plays a protective role in heavy-metal poisoning and it is associated with the metabolism of trace elements. Two MT isoforms, MT-I and MT-II, are expressed coordinately in all mammalian tissues, whereas MT-III is a brain-specific member of the MT family. MT-III binds zinc and copper physiologically and is seemed to have important neurophysiological and neuromodulatory functions. The MT functions and metal components of MTs in the brain after mercury vapor exposure are of much interest; however, until now they have not been fully examined. In this study, the influences of the lack of MT-I and MT-II on mercury accumulation in the brain and the changes of zinc and copper concentrations and metal components of MTs were examined after mercury vapor exposure by using MT-I, II null mice and 129/Sv (wild-type) mice as experimental animals. MT-I, II null mice and wild-type mice were exposed to mercury vapor or an air stream for 2 h and were killed 24 h later. The brain was dissected into the cerebral cortex, the cerebellum, and the hippocampus. The concentrations of mercury in each brain section were determined by cold vapor atomic absorption spectrometry. The concentrations of mercury, copper, and zinc in each brain section were determined by inductively coupled plasma mass spectrometry (ICP-MS). The mercury accumulated in brains after mercury vapor exposure for MT-I, II null mice and wild-type mice. The mercury levels of MT-I, II null mice in each brain section were significantly higher than those of wild-type mice after mercury vapor exposure. A significant change of zinc concentrations with the following mercury vapor exposure for MT-I, II null mice was observed only in the cerebellum analyzed by two-way analysis of

  7. Alfvén wave dynamics at the neighborhood of a 2.5D magnetic null-point

    Science.gov (United States)

    Sabri, S.; Vasheghani Farahani, S.; Ebadi, H.; Hosseinpour, M.; Fazel, Z.

    2018-05-01

    The aim of the present study is to highlight the energy transfer via the interaction of magnetohydrodynamic waves with a 2.5D magnetic null-point in a finite plasma-β regime of the solar corona. An initially symmetric Alfvén pulse at a specific distance from a magnetic null-point is kicked towards the isothermal null-point. A shock-capturing Godunov-type PLUTO code is used to solve the ideal magnetohydrodynamic set equations in the context of wave-plasma energy transfer. As the Alfvén wave propagates towards the magnetic null-point it experiences speed lowering which ends up in releasing energy along the separatrices. In this line owing to the Alfvén wave, a series of events take place that contribute towards coronal heating. Nonlinear induced waves are by products of the torsional Alfvén interaction with magnetic null-points. The energy of these induced waves which are fast magnetoacoustic (transverse) and slow magnetoacoustic (longitudinal) waves are supplied by the Alfvén wave. The nonlinearly induced density perturbations are proportional to the Alfvén wave energy loss. This supplies energy for the propagation of fast and slow magnetoacoustic waves, where in contrast to the fast wave the slow wave experiences a continuous energy increase. As such, the slow wave may transfer its energy to the medium at later times, maintaining a continuous heating mechanism at the neighborhood of a magnetic null-point.

  8. Deficient and Null Variants of SERPINA1 Are Proteotoxic in a Caenorhabditis elegans Model of α1-Antitrypsin Deficiency.

    Directory of Open Access Journals (Sweden)

    Erin E Cummings

    Full Text Available α1-antitrypsin deficiency (ATD predisposes patients to both loss-of-function (emphysema and gain-of-function (liver cirrhosis phenotypes depending on the type of mutation. Although the Z mutation (ATZ is the most prevalent cause of ATD, >120 mutant alleles have been identified. In general, these mutations are classified as deficient (<20% normal plasma levels or null (<1% normal levels alleles. The deficient alleles, like ATZ, misfold in the ER where they accumulate as toxic monomers, oligomers and aggregates. Thus, deficient alleles may predispose to both gain- and loss-of-function phenotypes. Null variants, if translated, typically yield truncated proteins that are efficiently degraded after being transiently retained in the ER. Clinically, null alleles are only associated with the loss-of-function phenotype. We recently developed a C. elegans model of ATD in order to further elucidate the mechanisms of proteotoxicity (gain-of-function phenotype induced by the aggregation-prone deficient allele, ATZ. The goal of this study was to use this C. elegans model to determine whether different types of deficient and null alleles, which differentially affect polymerization and secretion rates, correlated to any extent with proteotoxicity. Animals expressing the deficient alleles, Mmalton, Siiyama and S (ATS, showed overall toxicity comparable to that observed in patients. Interestingly, Siiyama expressing animals had smaller intracellular inclusions than ATZ yet appeared to have a greater negative effect on animal fitness. Surprisingly, the null mutants, although efficiently degraded, showed a relatively mild gain-of-function proteotoxic phenotype. However, since null variant proteins are degraded differently and do not appear to accumulate, their mechanism of proteotoxicity is likely to be different to that of polymerizing, deficient mutants. Taken together, these studies showed that C. elegans is an inexpensive tool to assess the proteotoxicity of

  9. Demonstrating Broadband Billion-to-One Contrast with the Visible Nulling Coronagraph

    Science.gov (United States)

    Hicks, Brian A.; Lyon, Richard G.; Petrone, Peter, III; Miller, Ian J.; Bolcar, Matthew R.; Clampin, Mark; Helmbrecht, Michael A.; Mallik, Udayan

    2015-01-01

    The key to broadband operation of the Visible Nulling Coronagraph (VNC) is achieving a condition of quasi- achromatic destructive interference between combined beams. Here we present efforts towards meeting this goal using Fresnel rhombs in each interferometric arm as orthogonally aligned half wave phase retarders. The milestone goal of the demonstration is to achieve 1 × 10-9 contrast at 2/D over a 40 nm bandpass centered at 633 nm. Rhombs have been designed and fabricated, and a multi-step approach to alignment using coarse positioners for each rhomb and pair has been developed to get within range of piezo stages used for fine positioning. The previously demonstrated narrowband VNC sensing and control approach that uses a segmented deformable mirror is being adapted to broadband to include fine positioning of the piezo-mounted rhombs, all demonstrated in a low-pressure environment.

  10. Inverse source problem and null controllability for multidimensional parabolic operators of Grushin type

    International Nuclear Information System (INIS)

    Beauchard, K; Cannarsa, P; Yamamoto, M

    2014-01-01

    The approach to Lipschitz stability for uniformly parabolic equations introduced by Imanuvilov and Yamamoto in 1998 based on Carleman estimates, seems hard to apply to the case of Grushin-type operators of interest to this paper. Indeed, such estimates are still missing for parabolic operators degenerating in the interior of the space domain. Nevertheless, we are able to prove Lipschitz stability results for inverse source problems for such operators, with locally distributed measurements in an arbitrary space dimension. For this purpose, we follow a mixed strategy which combines the approach due to Lebeau and Robbiano, relying on Fourier decomposition and Carleman inequalities for heat equations with non-smooth coefficients (solved by the Fourier modes). As a corollary, we obtain a direct proof of the observability of multidimensional Grushin-type parabolic equations, with locally distributed observations—which is equivalent to null controllability with locally distributed controls. (paper)

  11. Null to time-like infinity Green’s functions for asymptotic symmetries in Minkowski spacetime

    International Nuclear Information System (INIS)

    Campiglia, Miguel

    2015-01-01

    We elaborate on the Green’s functions that appeared in http://dx.doi.org/10.1007/JHEP07(2015)115http://arxiv.org/abs/1509.01406 when generalizing, from massless to massive particles, various equivalences between soft theorems and Ward identities of large gauge symmetries. We analyze these Green’s functions in considerable detail and show that they form a hierarchy of functions which describe ‘boundary to bulk’ propagators for large U(1) gauge parameters, supertranslations and sphere vector fields respectively. As a consistency check we verify that the Green’s functions associated to the large diffeomorphisms map the Poincare group at null infinity to the Poincare group at time-like infinity.

  12. Impaired insulin secretion and glucose intolerance in synaptotagmin-7 null mutant mice

    DEFF Research Database (Denmark)

    Gustavsson, Natalia; Lao, Ye; Maximov, Anton

    2008-01-01

    and insulin release. Here, we show that synaptotagmin-7 is required for the maintenance of systemic glucose tolerance and glucose-stimulated insulin secretion. Mutant mice have normal insulin sensitivity, insulin production, islet architecture and ultrastructural organization, and metabolic and calcium...... secretion in pancreatic beta-cells. Of these other synaptotagmins, synaptotagmin-7 is one of the most abundant and is present in pancreatic beta-cells. To determine whether synaptotagmin-7 regulates Ca(2+)-dependent insulin secretion, we analyzed synaptotagmin-7 null mutant mice for glucose tolerance...... responses but exhibit impaired glucose-induced insulin secretion, indicating a calcium-sensing defect during insulin-containing secretory granule exocytosis. Taken together, our findings show that synaptotagmin-7 functions as a positive regulator of insulin secretion and may serve as a calcium sensor...

  13. On null tests of time-reversal invariance in scattering and reactions

    International Nuclear Information System (INIS)

    Conzett, H.E.

    1993-01-01

    There have been suggestions in the literature, both recently and in the more distant past, that, in the lowest-order Born approximation, time-reversal (T)-odd experimental observables in certain reactions are required by T-symmetry to vanish. These observables are the final-state spin-correlation coefficient C xy in the reaction e + e - → τ + τ - and the target analysing power A oy in the inclusive process ep → eX with a polarized proton target. These assertions are in direct conflict with a theorem that states that there can be no null-test of T-symmetry in such processes; that is, T-symmetry does not require any single observable to vanish. This talk addresses the resolution of that conflict

  14. Null geodesics and shadow of a rotating black hole in extended Chern-Simons modified gravity

    International Nuclear Information System (INIS)

    Amarilla, Leonardo; Eiroa, Ernesto F.; Giribet, Gaston

    2010-01-01

    The Chern-Simons modification to general relativity in four dimensions consists of adding to the Einstein-Hilbert term a scalar field that couples to the first-class Pontryagin density. In this theory, which has attracted considerable attention recently, the Schwarzschild metric persists as an exact solution, and this is why this model resists several observational constraints. In contrast, the spinning black hole solution of the theory is not given by the Kerr metric but by a modification of it, so far only known for slow rotation and small coupling constant. In the present paper, we show that, in this approximation, the null geodesic equation can be integrated, and this allows us to investigate the shadow cast by a black hole. We discuss how, in addition to the angular momentum of the solution, the coupling to the Chern-Simons term deforms the shape of the shadow.

  15. Estimating the Proportion of True Null Hypotheses in Multiple Testing Problems

    Directory of Open Access Journals (Sweden)

    Oluyemi Oyeniran

    2016-01-01

    Full Text Available The problem of estimating the proportion, π0, of the true null hypotheses in a multiple testing problem is important in cases where large scale parallel hypotheses tests are performed independently. While the problem is a quantity of interest in its own right in applications, the estimate of π0 can be used for assessing or controlling an overall false discovery rate. In this article, we develop an innovative nonparametric maximum likelihood approach to estimate π0. The nonparametric likelihood is proposed to be restricted to multinomial models and an EM algorithm is also developed to approximate the estimate of π0. Simulation studies show that the proposed method outperforms other existing methods. Using experimental microarray datasets, we demonstrate that the new method provides satisfactory estimate in practice.

  16. Divertor target profiles and recycling studies in TCV single null lower standard discharges

    International Nuclear Information System (INIS)

    Pitts, R.A.; Nieswand, C.; Weisen, H.

    1996-05-01

    A 'standard', single null lower diverted discharge has been developed to enable continuous monitoring of the first wall conditions and to characterise the effectiveness and influence of wall conditioning in the TCV tokamak. Measurements over a period encompassing nearly 2000 ohmic discharges of varying configuration and input power show the global confinement time and main plasma impurity concentrations to be good general indicators of the first wall condition, whilst divertor target profiles demonstrate strikingly the short term beneficial effects of He glow. Good agreement, consistent with a reduction in recycling at the plates is found between the predictions of the fluid code UEDGE and the observed outer divertor profiles of T e and n e before and after He glow. (author) 5 figs., 7 refs

  17. Development of a two-dimensional skin friction balance nulling circuit using multivariable control theory

    Science.gov (United States)

    Tripp, John S.; Patek, Stephen D.

    1988-01-01

    Measurement of planar skin friction forces in aerodynamic testing currently requires installation of two perpendicularly mounted, single-axis balances; consequently, force components must be sensed at two distinct locations. A two-axis instrument developed at the Langley Research Center to overcome this disadvantage allows measurement of a two-dimensional force at one location. This paper describes a feedback-controlled nulling circuit developed for the NASA two-axis balance which, without external compensation, is inherently unstable because of its low friction mechanical design. Linear multivariable control theory is applied to an experimentally validated mathematical model of the balance to synthesize a state-variable feedback control law. Pole placement techniques and computer simulation studies are employed to select eigenvalues which provide ideal transient response with decoupled sensing dynamics.

  18. Preamble and pilot symbol design for channel estimation in OFDM systems with null subcarriers

    Directory of Open Access Journals (Sweden)

    Ohno Shuichi

    2011-01-01

    Full Text Available Abstract In this article, design of preamble for channel estimation and pilot symbols for pilot-assisted channel estimation in orthogonal frequency division multiplexing system with null subcarriers is studied. Both the preambles and pilot symbols are designed to minimize the l 2 or the l ∞ norm of the channel estimate mean-squared errors (MSE in frequency-selective environments. We use convex optimization technique to find optimal power distribution to the preamble by casting the MSE minimization problem into a semidefinite programming problem. Then, using the designed optimal preamble as an initial value, we iteratively select the placement and optimally distribute power to the selected pilot symbols. Design examples consistent with IEEE 802.11a as well as IEEE 802.16e are provided to illustrate the superior performance of our proposed method over the equi-spaced equi-powered pilot symbols and the partially equi-spaced pilot symbols.

  19. Null Geodesics and Strong Field Gravitational Lensing of Black Hole with Global Monopole

    International Nuclear Information System (INIS)

    Iftikhar, Sehrish; Sharif, M.

    2015-01-01

    We study two interesting features of a black hole with an ordinary as well as phantom global monopole. Firstly, we investigate null geodesics which imply unstable orbital motion of particles for both cases. Secondly, we evaluate deflection angle in strong field regime. We then find Einstein rings, magnifications, and observables of the relativistic images for supermassive black hole at the center of galaxy NGC4486B. We also examine time delays for different galaxies and present our results numerically. It is found that the deflection angle for ordinary/phantom global monopole is greater/smaller than that of Schwarzschild black hole. In strong field limit, the remaining properties of these black holes are quite different from the Schwarzschild black hole

  20. Calculations of transient fields in the Felix experiments at Argonne using null field integrated techniques

    International Nuclear Information System (INIS)

    Han, H.C.; Davey, K.R.; Turner, L.

    1985-08-01

    The transient eddy current problem is characteristically computationally intensive. The motivation for this research was to realize an efficient, accurate, solution technique involving small matrices via an eigenvalue approach. Such a technique is indeed realized and tested using the null field integral technique. Using smart (i.e., efficient, global) basis functions to represent unknowns in terms of a minimum number of unknowns, homogeneous eigenvectors and eigenvalues are first determined. The general excitatory response is then represented in terms of these eigenvalues/eigenvectors. Excellent results are obtained for the Argonne Felix cylinder experiments using a 4 x 4 matrix. Extension to the 3-D problem (short cylinder) is set up in terms of an 8 x 8 matrix